A portable personal cooling system for mine rescue operations

NASA Technical Reports Server (NTRS)

Webbon, B.; Williams, B.; Kirk, P.; Elkins, W.; Stein, R.

1977-01-01

Design of a portable personal cooling system to reduce physiological stress in high-temperature, high-humidity conditions is discussed. The system, based on technology used in the thermal controls of space suits, employs a combination of head and thoracic insulation and cooling through a heat sink unit. Average metabolic rates, heart rates, rectal temperature increase and sweat loss were monitored for test subjects wearing various configurations of the cooling system, as well as for a control group. The various arrangements of the cooling garment were found to provide significant physiological benefits; however, increases in heat transfer rate of the cooling unit and more effective insulation are suggested to improve the system's function.

Evaporative cooling enhanced cold storage system

DOEpatents

Carr, Peter

1991-01-01

The invention provides an evaporatively enhanced cold storage system wherein a warm air stream is cooled and the cooled air stream is thereafter passed into contact with a cold storage unit. Moisture is added to the cooled air stream prior to or during contact of the cooled air stream with the cold storage unit to effect enhanced cooling of the cold storage unit due to evaporation of all or a portion of the added moisture. Preferably at least a portion of the added moisture comprises water condensed during the cooling of the warm air stream.

Evaporative cooling enhanced cold storage system

DOEpatents

Carr, P.

1991-10-15

The invention provides an evaporatively enhanced cold storage system wherein a warm air stream is cooled and the cooled air stream is thereafter passed into contact with a cold storage unit. Moisture is added to the cooled air stream prior to or during contact of the cooled air stream with the cold storage unit to effect enhanced cooling of the cold storage unit due to evaporation of all or a portion of the added moisture. Preferably at least a portion of the added moisture comprises water condensed during the cooling of the warm air stream. 3 figures.

Performance Analysis of XCPC Powered Solar Cooling Demonstration Project

NASA Astrophysics Data System (ADS)

Widyolar, Bennett K.

A solar thermal cooling system using novel non-tracking External Compound Parabolic Concentrators (XCPC) has been built at the University of California, Merced and operated for two cooling seasons. Its performance in providing power for space cooling has been analyzed. This solar cooling system is comprised of 53.3 m2 of XCPC trough collectors which are used to power a 23 kW double effect (LiBr) absorption chiller. This is the first system that combines both XCPC and absorption chilling technologies. Performance of the system was measured in both sunny and cloudy conditions, with both clean and dirty collectors. It was found that these collectors are well suited at providing thermal power to drive absorption cooling systems and that both the coinciding of available thermal power with cooling demand and the simplicity of the XCPC collectors compared to other solar thermal collectors makes them a highly attractive candidate for cooling projects.

A simple model for closure temperature of a trace element in cooling bi-mineralic systems

NASA Astrophysics Data System (ADS)

Liang, Yan

2015-09-01

Closure temperature is defined as the lower temperature limit at which the element of interest effectively ceases diffusive exchange with its surrounding medium during cooling. Here we generalize the classic equation of Dodson (1973) for cooling mono-mineralic systems to cooling bi-mineralic aggregates by considering diffusive exchange of a trace element between the two minerals in a closed system. We present a simple analytical model that includes key parameters affecting the closure temperature of a trace element in cooling bi-mineralic systems: cooling rate, temperature-dependent diffusion coefficients for the trace element in the two minerals, temperature-dependent partition coefficient of the trace element between the two minerals, effective grain sizes of the two minerals, and volume proportions of the minerals in the system. We show that closure temperatures of a trace element in cooling bi-mineralic systems are bounded by the closure temperatures of the trace element in the two mono-mineralic systems and that our generalized model reduces to Dodson's equation when one of the mineral serves as "an effective infinite" reservoir to the other mineral. Application to closure temperatures of REE in orthopyroxene and clinopyroxene bi-mineralic systems highlights the importance of REE diffusion and partitioning in the pyroxenes as well as clinopyroxene modal abundance and grain size in the systems. Closure temperatures for REE in two-pyroxene bearing equigranular rocks are controlled primarily by diffusion in orthopyroxene unless the modal abundance of clinopyroxene is very small. This has important bearings on the interpretation of temperatures derived from the REE-in-two-pyroxene thermometer.

Experimental investigation of biomimetic self-pumping and self-adaptive transpiration cooling.

PubMed

Jiang, Pei-Xue; Huang, Gan; Zhu, Yinhai; Xu, Ruina; Liao, Zhiyuan; Lu, Taojie

2017-09-01

Transpiration cooling is an effective way to protect high heat flux walls. However, the pumps for the transpiration cooling system make the system more complex and increase the load, which is a huge challenge for practical applications. A biomimetic self-pumping transpiration cooling system was developed inspired by the process of trees transpiration that has no pumps. An experimental investigation showed that the water coolant automatically flowed from the water tank to the hot surface with a height difference of 80 mm without any pumps. A self-adaptive transpiration cooling system was then developed based on this mechanism. The system effectively cooled the hot surface with the surface temperature kept to about 373 K when the heating flame temperature was 1639 K and the heat flux was about 0.42 MW m -2 . The cooling efficiency reached 94.5%. The coolant mass flow rate adaptively increased with increasing flame heat flux from 0.24 MW m -2 to 0.42 MW m -2 while the cooled surface temperature stayed around 373 K. Schlieren pictures showed a protective steam layer on the hot surface which blocked the flame heat flux to the hot surface. The protective steam layer thickness also increased with increasing heat flux.

The efficacy of biocides and other chemical additives in cooling water systems in the control of amoebae.

PubMed

Critchley, M; Bentham, R

2009-03-01

In vitro experiments were undertaken to evaluate biocide formulations commonly used in cooling water systems against protozoa previously isolated from cooling towers. The investigations evaluated the efficacy of these formulations against amoebic cysts and trophozoites. Laboratory challenges against protozoa isolated from cooling towers using chlorine, bromine and isothiazolinone biocides showed that all were effective after 4 h. The presence of molybdate and organic phosphates resulted in longer kill times for bromine and isothiazolinones. All treatments resulted in no detectable viable protozoa after 4 h of exposure. The chemical disinfection of planktonic protozoa in cooling water systems is strongly influenced by the residence time of the formulation and less so by its active constituent. Bromine and isothiazolinone formulations may require higher dosage of concentrations than currently practiced if used in conjunction with molybdate- and phosphate-based scale/corrosion inhibitors. Cooling water systems are complex microbial ecosystems in which predator-prey relationships play a key role in the dissemination of Legionella. This study demonstrated that at recommended dosing concentrations, biocides had species-specific effects on environmental isolates of amoebae that may act as reservoirs for Legionella multiplication in cooling water systems.

Possibilities of application of the swirling flows in cooling systems of laser mirrors

NASA Astrophysics Data System (ADS)

Shanin, Yu; Chernykh, A.

2018-03-01

The paper presents analytical investigations into advanced cooling systems of the laser mirrors with heat exchange intensification by methods of ordered vortex impact on a coolant flow structure. Advantages and effectiveness of the proposed cooling systems have been estimated to reduction displacement of an optical mirror surface due to a flexure.

Study toward high-performance thermally driven air-conditioning systems

NASA Astrophysics Data System (ADS)

Miyazaki, Takahiko; Miyawaki, Jin; Ohba, Tomonori; Yoon, Seong-Ho; Saha, Bidyut Baran; Koyama, Shigeru

2017-01-01

The Adsorption heat pump is a technology for cooling and heating by using hot water as a driving heat source. It will largely contribute to energy savings when it is driven by solar thermal energy or waste heat. The system is available in the market worldwide, and there are many examples of application to heat recovery in factories and to solar cooling systems. In the present system, silica gel and zeolite are popular adsorbents in combination with water refrigerant. Our study focused on activated carbon-ethanol pair for adsorption cooling system because of the potential to compete with conventional systems in terms of coefficient of performance. In addition, activated-ethanol pair can generally produce larger cooling effect by an adsorption-desorption cycle compared with that of the conventional pairs in terms of cooling effect per unit adsorbent mass. After the potential of a commercially available activated carbon with highest level specific surface area was evaluated, we developed a new activated carbon that has the optimum pore characteristics for the purpose of solar or waste heat driven cooling systems. In this paper, comparison of refrigerants for adsorption heat pump application is presented, and a newly developed activated carbon for ethanol adsorption heat pump is introduced.

Performance characteristic of hybrid cooling system based on cooling pad and evaporator

NASA Astrophysics Data System (ADS)

Yoon, J. I.; Son, C. H.; Choi, K. H.; Kim, Y. B.; Sung, Y. H.; Roh, S. J.; Kim, Y. M.; Seol, S. H.

2018-01-01

In South Korea, most of domestic animals such as pigs and chickens might die due to thermal diseases if they are exposed to the high temperature consistently. In order to save them from the heat wave, numerous efforts have been carried out: installing a shade net, adjusting time of feeding, spraying mist and setting up a circulation fan. However, these methods have not shown significant improvements. Thus, this study proposes a hybrid cooling system combining evaporative cooler and air-conditioner in order to resolve the conventional problems caused by the high temperature in the livestock industry. The problem of cooling systems using evaporative cooling pads is that they are not effective for eliminating huge heat load due to their limited capacity. And, temperature of the supplied air cannot be low enough compared to conventional air-conditioning systems. On the other hand, conventional air-conditioning systems require relatively expensive installation cost, and high operating cost compared to evaporative cooling system. The hybrid cooling system makes up for the lack of cooling capacity of the evaporative cooler by employing the conventional air-conditioner. Additionally, temperature of supplied air can be lowered enough. In the hybrid cooling system, induced air by a fan is cooled by the evaporation of water in the cooling pad, and it is cooled again by an evaporator in the air-conditioner. Therefore, the more economical operation is possible due to additionally obtained cooling capacity from the cooling pads. Major results of experimental analysis of hybrid cooling system are as follows. The compressor power consumption of the hybrid cooling system is about 23% lower, and its COP is 17% higher than that of the conventional air-conditioners. Regarding the condition of changing ambient temperature, the total power consumption decreased by about 5% as the ambient temperature changed from 28.7°C to 31.7°C. Cooling capacity and COP also presented about 3% and 1% of minor difference at the same comparison condition.

Comprehensive Evaluation of Biological Growth Control by Chlorine-Based Biocides in Power Plant Cooling Systems Using Tertiary Effluent

PubMed Central

Chien, Shih-Hsiang; Dzombak, David A.; Vidic, Radisav D.

2013-01-01

Abstract Recent studies have shown that treated municipal wastewater can be a reliable cooling water alternative to fresh water. However, elevated nutrient concentration and microbial population in wastewater lead to aggressive biological proliferation in the cooling system. Three chlorine-based biocides were evaluated for the control of biological growth in cooling systems using tertiary treated wastewater as makeup, based on their biocidal efficiency and cost-effectiveness. Optimal chemical regimens for achieving successful biological growth control were elucidated based on batch-, bench-, and pilot-scale experiments. Biocide usage and biological activity in planktonic and sessile phases were carefully monitored to understand biological growth potential and biocidal efficiency of the three disinfectants in this particular environment. Water parameters, such as temperature, cycles of concentration, and ammonia concentration in recirculating water, critically affected the biocide performance in recirculating cooling systems. Bench-scale recirculating tests were shown to adequately predict the biocide residual required for a pilot-scale cooling system. Optimal residuals needed for proper biological growth control were 1, 2–3, and 0.5–1 mg/L as Cl2 for NaOCl, preformed NH2Cl, and ClO2, respectively. Pilot-scale tests also revealed that Legionella pneumophila was absent from these cooling systems when using the disinfectants evaluated in this study. Cost analysis showed that NaOCl is the most cost-effective for controlling biological growth in power plant recirculating cooling systems using tertiary-treated wastewater as makeup. PMID:23781129

Comprehensive Evaluation of Biological Growth Control by Chlorine-Based Biocides in Power Plant Cooling Systems Using Tertiary Effluent.

PubMed

Chien, Shih-Hsiang; Dzombak, David A; Vidic, Radisav D

2013-06-01

Recent studies have shown that treated municipal wastewater can be a reliable cooling water alternative to fresh water. However, elevated nutrient concentration and microbial population in wastewater lead to aggressive biological proliferation in the cooling system. Three chlorine-based biocides were evaluated for the control of biological growth in cooling systems using tertiary treated wastewater as makeup, based on their biocidal efficiency and cost-effectiveness. Optimal chemical regimens for achieving successful biological growth control were elucidated based on batch-, bench-, and pilot-scale experiments. Biocide usage and biological activity in planktonic and sessile phases were carefully monitored to understand biological growth potential and biocidal efficiency of the three disinfectants in this particular environment. Water parameters, such as temperature, cycles of concentration, and ammonia concentration in recirculating water, critically affected the biocide performance in recirculating cooling systems. Bench-scale recirculating tests were shown to adequately predict the biocide residual required for a pilot-scale cooling system. Optimal residuals needed for proper biological growth control were 1, 2-3, and 0.5-1 mg/L as Cl 2 for NaOCl, preformed NH 2 Cl, and ClO 2 , respectively. Pilot-scale tests also revealed that Legionella pneumophila was absent from these cooling systems when using the disinfectants evaluated in this study. Cost analysis showed that NaOCl is the most cost-effective for controlling biological growth in power plant recirculating cooling systems using tertiary-treated wastewater as makeup.

Conduction cooling systems for linear accelerator cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kephart, Robert

A conduction cooling system for linear accelerator cavities. The system conducts heat from the cavities to a refrigeration unit using at least one cavity cooler interconnected with a cooling connector. The cavity cooler and cooling connector are both made from solid material having a very high thermal conductivity of approximately 1.times.10.sup.4 W m.sup.-1 K.sup.-1 at temperatures of approximately 4 degrees K. This allows for very simple and effective conduction of waste heat from the linear accelerator cavities to the cavity cooler, along the cooling connector, and thence to the refrigeration unit.

Effect of Cooling Rates on Shape and Crystal Size Distributions of Mefenamic Acid Polymorph in Ethyl Acetate

NASA Astrophysics Data System (ADS)

Mudalip, S. K. Abdul; Adam, F.; Parveen, J.; Abu Bakar, M. R.; Amran, N.; Sulaiman, S. Z.; Che Man, R.; Arshad, Z. I. Mohd; Shaarani, S. Md.

2017-06-01

This study investigate the effect of cooling rates on mefenamic acid crystallisation in ethyl acetate. The cooling rate was varied from 0.2 to 5 °C/min. The in-line conductivity system and turbidity system were employed to detect the onset of the crystallization process. The crystals produced were analysed using optical microscopy and Fourier transform infrared spectroscopy (FTIR). It was found that the crystals produced at different cooling rates were needle-like and exhibit polymorphic form type I. However, the aspect ratio and crystal size distributions were varied with the increased of cooling rate. A high crystals aspect ratio and narrower CSD (100-900 μm) was obtained at cooling rate of 0.5 °C/min. Thus, can be suggested as the most suitable cooling rate for crystallization of mefenamic acid in ethyl acetate.

Characteristic Evaluation on Cooling Performance of Thermoelectric Modules.

PubMed

Seo, Sae Rom; Han, Seungwoo

2015-10-01

The aim of this work is to develop a performance evaluation system for thermoelectric cooling modules. We describe the design of such a system, composed of a vacuum chamber with a heat sink along with a metal block to measure the absorbed heat Qc. The system has a simpler structure than existing water-cooled or air-cooled systems. The temperature difference between the cold and hot sides of the thermoelectric module ΔT can be accurately measured without any effects due to convection, and the temperature equilibrium time is minimized compared to a water-cooled system. The evaluation system described here can be used to measure characteristic curves of Qc as a function of ΔT, as well as the current-voltage relations. High-performance thermoelectric systems can therefore be developed using optimal modules evaluated with this system.

Maximization of the Thermoelectric Cooling of a Graded Peltier Device by Analytical Heat-Equation Resolution

NASA Astrophysics Data System (ADS)

Thiébaut, E.; Goupil, C.; Pesty, F.; D'Angelo, Y.; Guegan, G.; Lecoeur, P.

2017-12-01

Increasing the maximum cooling effect of a Peltier cooler can be achieved through material and device design. The use of inhomogeneous, functionally graded materials may be adopted in order to increase maximum cooling without improvement of the Z T (figure of merit); however, these systems are usually based on the assumption that the local optimization of the Z T is the suitable criterion to increase thermoelectric performance. We solve the heat equation in a graded material and perform both analytical and numerical analysis of a graded Peltier cooler. We find a local criterion that we use to assess the possible improvement of graded materials for thermoelectric cooling. A fair improvement of the cooling effect (up to 36%) is predicted for semiconductor materials, and the best graded system for cooling is described. The influence of the equation of state of the electronic gas of the material is discussed, and the difference in term of entropy production between the graded and the classical system is also described.

Hemodynamic Responses to Head and Neck Cooling

NASA Technical Reports Server (NTRS)

Ku, Yu-Tsuan E.; Carbo, Jorge E.; Montgomery, Leslie D.; Webbon, Bruce W.

1994-01-01

Personal thermoregulatory systems which provide head and neck cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objective of this study was to measure the scalp temperature and circulatory responses during use of one commercially available thermal control system. The Life Support Systems, Inc. Mark VII portable cooling system and a liquid cooling helmet were used in this study. Two EEG electrodes and one skin temperature transducer were placed on the anterior midline of the scalp to measure the scalp blood and temperature. Blood flow was measured using a bipolar impedance rheograph. Ten subjects, seated in an upright position at normal room temperature, were tested at high, medium, moderate, moderate-low and low coolant temperatures. Scalp blood flow was recorded continuously using a computer data acquisition system with a sampling frequency of 200 Hz. Scalp temperature and cooling helmet Inlet temperature was logged periodically during the test period. This study quantifies the effect of head cooling upon scalp temperature and blood flow. These data may also be used to select operational specifications of the head cooling system for biomedical applications such as the treatment of migraine headaches, scalp cooling during chemotherapy, and cooling of multiple sclerosis patients.

On importance assessment of aging multi-state system

NASA Astrophysics Data System (ADS)

Frenkel, Ilia; Khvatskin, Lev; Lisnianski, Anatoly

2017-01-01

Modern high-tech equipment requires precise temperature control and effective cooling below the ambient temperature. Greater cooling efficiencies will allow equipment to be operated for longer periods without overheating, providing a greater return on investment and increased in availability of the equipment. This paper presents application of the Lz-transform method to importance assessment of aging multi-state water-cooling system used in one of Israeli hospitals. The water cooling system consists of 3 principal sub-systems: chillers, heat exchanger and pumps. The performance of the system and the sub-systems is measured by their produced cooling capacity. Heat exchanger is an aging component. Straightforward Markov method applied to solve this problem will require building of a system model with numerous numbers of states and solving a corresponding system of multiple differential equations. Lz-transform method, which is used for calculation of the system elements importance, drastically simplified the solution. Numerical example is presented to illustrate the described approach.

Cooling system for a nuclear reactor

DOEpatents

Amtmann, Hans H.

1982-01-01

A cooling system for a gas-cooled nuclear reactor is disclosed which includes at least one primary cooling loop adapted to pass coolant gas from the reactor core and an associated steam generator through a duct system having a main circulator therein, and at least one auxiliary cooling loop having communication with the reactor core and adapted to selectively pass coolant gas through an auxiliary heat exchanger and circulator. The main and auxiliary circulators are installed in a common vertical cavity in the reactor vessel, and a common return duct communicates with the reactor core and intersects the common cavity at a junction at which is located a flow diverter valve operative to effect coolant flow through either the primary or auxiliary cooling loops.

Sub-ambient non-evaporative fluid cooling with the sky

NASA Astrophysics Data System (ADS)

Goldstein, Eli A.; Raman, Aaswath P.; Fan, Shanhui

2017-09-01

Cooling systems consume 15% of electricity generated globally and account for 10% of global greenhouse gas emissions. With demand for cooling expected to grow tenfold by 2050, improving the efficiency of cooling systems is a critical part of the twenty-first-century energy challenge. Building upon recent demonstrations of daytime radiative sky cooling, here we demonstrate fluid cooling panels that harness radiative sky cooling to cool fluids below the air temperature with zero evaporative losses, and use almost no electricity. Over three days of testing, we show that the panels cool water up to 5 ∘C below the ambient air temperature at water flow rates of 0.2 l min-1 m-2, corresponding to an effective heat rejection flux of up to 70 W m-2. We further show through modelling that, when integrated on the condenser side of the cooling system of a two-storey office building in a hot dry climate (Las Vegas, USA), electricity consumption for cooling during the summer could be reduced by 21% (14.3 MWh).

An alternative cooling system to enhance the safety of Li-ion battery packs

NASA Astrophysics Data System (ADS)

Kizilel, Riza; Sabbah, Rami; Selman, J. Robert; Al-Hallaj, Said

A passive thermal management system is evaluated for high-power Li-ion packs under stressful or abusive conditions, and compared with a purely air-cooling mode under normal and abuse conditions. A compact and properly designed passive thermal management system utilizing phase change material (PCM) provides faster heat dissipation than active cooling during high pulse power discharges while preserving sufficiently uniform cell temperature to ensure the desirable cycle life for the pack. This study investigates how passive cooling with PCM contributes to preventing the propagation of thermal runaway in a single cell or adjacent cells due to a cell catastrophic failure. Its effectiveness is compared with that of active cooling by forced air flow or natural convection using the same compact module and pack configuration corresponding to the PCM matrix technology. The effects of nickel tabs and spacing between the cells were also studied.

RFQ (radio-frequency quadrupole) accelerator tuning system

DOEpatents

Bolie, V.W.

1988-04-12

A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in responsive to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. 3 figs., 2 tabs.

Air-Cooled Stack Freeze Tolerance Freeze Failure Modes and Freeze Tolerance Strategies for GenDriveTM Material Handling Application Systems and Stacks Final Scientific Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hancock, David, W.

2012-02-14

Air-cooled stack technology offers the potential for a simpler system architecture (versus liquid-cooled) for applications below 4 kilowatts. The combined cooling and cathode air allows for a reduction in part count and hence a lower cost solution. However, efficient heat rejection challenges escalate as power and ambient temperature increase. For applications in ambient temperatures below freezing, the air-cooled approach has additional challenges associated with not overcooling the fuel cell stack. The focus of this project was freeze tolerance while maintaining all other stack and system requirements. Through this project, Plug Power advanced the state of the art in technology formore » air-cooled PEM fuel cell stacks and related GenDrive material handling application fuel cell systems. This was accomplished through a collaborative work plan to improve freeze tolerance and mitigate freeze-thaw effect failure modes within innovative material handling equipment fuel cell systems designed for use in freezer forklift applications. Freeze tolerance remains an area where additional research and understanding can help fuel cells to become commercially viable. This project evaluated both stack level and system level solutions to improve fuel cell stack freeze tolerance. At this time, the most cost effective solutions are at the system level. The freeze mitigation strategies developed over the course of this project could be used to drive fuel cell commercialization. The fuel cell system studied in this project was Plug Power's commercially available GenDrive platform providing battery replacement for equipment in the material handling industry. The fuel cell stacks were Ballard's commercially available FCvelocity 9SSL (9SSL) liquid-cooled PEM fuel cell stack and FCvelocity 1020ACS (Mk1020) air-cooled PEM fuel cell stack.« less

IR window design for hypersonic missile seekers: thermal shock and cooling systems

NASA Astrophysics Data System (ADS)

Hingst, Uwe; Koerber, Stefan

2001-10-01

Infra-red (IR) seekers on missiles at high Mach-numbers in the lower tier air defence often suffer from degradation in performance due to aerothermodynamic effects. The kind and rate of degradation depends on the geometric design (shape) and location of the IR-window. Optimal design may reduce those effects but still misses to totally withstand the imposed thermal stresses (thermal shock). Proper thermal protection systems and/or window cooling systems will be needed. The first part of this paper deals particularly with passive IR- window design features to reduce the thermal stresses. A series of wind-tunnel testings focused on the thermal shock behavior of different IR-window shapes under critical flight conditions. The variation of typical design parameters demonstrates the available features to reduce thermal shock by passive ways. The second part presents active thermal stress reduction devices, e.g. an active cooling system. Among others the most efficient reduction of thermal heating is based on three components: A partial coverage of the IR-dome to protect most parts against heating effects, a rotating system bearing the IR-dome and a liquid spray-cooling system in the gap between the cover and the IR-dome. The hemispherical or pyramidal dome can be located either midways in the missile nose section or sideways on the structure. The liquid spray cooling system combines both, a heat exchange by fluid evaporation and a heat transfer by fluid and gas cross flow (convection), causing a low fluid consumption. Such a cooling system along with their driving parameters and the resulting analytical performance will be presented.

A comparison of 2 evaporative cooling systems on a commercial dairy farm in Saudi Arabia.

PubMed

Ortiz, X A; Smith, J F; Villar, F; Hall, L; Allen, J; Oddy, A; Al-Haddad, A; Lyle, P; Collier, R J

2015-12-01

Efficacy of 2 cooling systems (Korral Kool, KK, Korral Kool Inc., Mesa, AZ; FlipFan dairy system, FF, Schaefer Ventilation Equipment LLC, Sauk Rapids, MN) was estimated utilizing 400 multiparous Holstein dairy cows randomly assigned to 1 of 4 cooled California-style shade pens (2 shade pens per cooling system). Each shaded pen contained 100 cows (days in milk=58±39, milk production=56±18 kg/d, and lactation=3±1). Production data (milk yield and reproductive performance) were collected during 3mo (June-August, 2013) and physiological responses (core body temperature, respiration rates, surface temperatures, and resting time) were measured in June and July to estimate responses of cows to the 2 different cooling systems. Water and electricity consumption were recorded for each system. Cows in the KK system displayed slightly lower respiration rates in the month of June and lower surface temperatures in June and July. However, no differences were observed in the core body temperature of cows, resting time, feed intake, milk yield, services/cow, and conception rate between systems. The FF system used less water and electricity during this study. In conclusion, both cooling systems (KK and FF) were effective in mitigating the negative effects of heat stress on cows housed in arid environments, whereas the FF system consumed less water and electricity and did not require use of curtains on the shade structure. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Sleeve reaction chamber system

DOEpatents

Northrup, M Allen [Berkeley, CA; Beeman, Barton V [San Mateo, CA; Benett, William J [Livermore, CA; Hadley, Dean R [Manteca, CA; Landre, Phoebe [Livermore, CA; Lehew, Stacy L [Livermore, CA; Krulevitch, Peter A [Pleasanton, CA

2009-08-25

A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

The design and testing of a cooling system using mixed solid cryogen for a portable superconducting magnetic energy storage system

NASA Astrophysics Data System (ADS)

Kim, K. L.; Song, J. B.; Choi, J. H.; Kim, S. H.; Y Koh, D.; Seong, K. C.; Chang, H. M.; Lee, H. G.

2010-12-01

A cooling system that uses solid nitrogen (SN2) as an effective heat capacity enhancer was recently introduced to enhance the thermal stability of the HTS SMES. Since SN2 has a large enthalpy with minimal weight, it enables a portable system by increasing the recooling to recooling time period (RRTP). However, contact between the SN2 and HTS SMES magnet can be broken by repeated thermal disturbances (thermal 'dry-out' phenomena). Therefore, it is essential to improve thermal contact to allow full use of the heat capacity of SN2. This study evaluated the effect of using a mixture containing SN2 and a small amount of a liquid cryogen as a cooling system in the HTS SMES system. The performance of the cooling system was evaluated using the mixed cryogen and compared with that of SN2 alone. In addition, the role of liquid neon (Ne) as a heat exchanger between SN2 and the HTS SMES magnet is discussed.

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation

PubMed Central

Schmidt, Marvin; Ullrich, Johannes; Wieczorek, André; Frenzel, Jan; Eggeler, Gunther; Schütze, Andreas; Seelecke, Stefan

2016-01-01

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor compression based cooling process. Nickel-Titanium (Ni-Ti) based alloy systems, especially, show large elastocaloric effects. Furthermore, exhibit large latent heats which is a necessary material property for the development of an efficient solid-state based cooling process. A scientific test rig has been designed to investigate these processes and the elastocaloric effects in SMAs. The realized test rig enables independent control of an SMA's mechanical loading and unloading cycles, as well as conductive heat transfer between SMA cooling elements and a heat source/sink. The test rig is equipped with a comprehensive monitoring system capable of synchronized measurements of mechanical and thermal parameters. In addition to determining the process-dependent mechanical work, the system also enables measurement of thermal caloric aspects of the elastocaloric cooling effect through use of a high-performance infrared camera. This combination is of particular interest, because it allows illustrations of localization and rate effects — both important for efficient heat transfer from the medium to be cooled. The work presented describes an experimental method to identify elastocaloric material properties in different materials and sample geometries. Furthermore, the test rig is used to investigate different cooling process variations. The introduced analysis methods enable a differentiated consideration of material, process and related boundary condition influences on the process efficiency. The comparison of the experimental data with the simulation results (of a thermomechanically coupled finite element model) allows for better understanding of the underlying physics of the elastocaloric effect. In addition, the experimental results, as well as the findings based on the simulation results, are used to improve the material properties. PMID:27168093

Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation.

PubMed

Schmidt, Marvin; Ullrich, Johannes; Wieczorek, André; Frenzel, Jan; Eggeler, Gunther; Schütze, Andreas; Seelecke, Stefan

2016-05-02

Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor compression based cooling process. Nickel-Titanium (Ni-Ti) based alloy systems, especially, show large elastocaloric effects. Furthermore, exhibit large latent heats which is a necessary material property for the development of an efficient solid-state based cooling process. A scientific test rig has been designed to investigate these processes and the elastocaloric effects in SMAs. The realized test rig enables independent control of an SMA's mechanical loading and unloading cycles, as well as conductive heat transfer between SMA cooling elements and a heat source/sink. The test rig is equipped with a comprehensive monitoring system capable of synchronized measurements of mechanical and thermal parameters. In addition to determining the process-dependent mechanical work, the system also enables measurement of thermal caloric aspects of the elastocaloric cooling effect through use of a high-performance infrared camera. This combination is of particular interest, because it allows illustrations of localization and rate effects - both important for efficient heat transfer from the medium to be cooled. The work presented describes an experimental method to identify elastocaloric material properties in different materials and sample geometries. Furthermore, the test rig is used to investigate different cooling process variations. The introduced analysis methods enable a differentiated consideration of material, process and related boundary condition influences on the process efficiency. The comparison of the experimental data with the simulation results (of a thermomechanically coupled finite element model) allows for better understanding of the underlying physics of the elastocaloric effect. In addition, the experimental results, as well as the findings based on the simulation results, are used to improve the material properties.

Meta-analysis of the effects of microclimate cooling systems on human performance under thermal stressful environments: potential applications to occupational workers.

PubMed

Chan, Albert P C; Song, Wenfang; Yang, Yang

2015-01-01

This study aims to determine the appropriate microclimate cooling systems (MCSs) to reduce heat stress and improve human performance of occupational workers and their practicality in the occupational field. Meta-analysis was employed to summarize, analyze, and compare the effects of various MCSs on human performance with corresponding physiological and psychological responses, thereby providing solid suggestions for selecting suitable MCSs for occupational workers. Wearing MCSs significantly attenuated the increases in core temperature (-0.34 °C/h) and sweating rate (-0.30 L/h), and significantly improved human performance (+29.9%, effect size [EFS] = 1.1) compared with no cooling condition (CON). Cold air-cooled garments (ACG-Cs; +106.2%, EFS = 2.32) exhibited greater effects on improving human performance among various microclimate cooling garments (MCGs), followed by liquid cooling garments (LCGs; +68.1%, EFS = 1.86) and hybrid cooling garment combining air and liquid cooling (HBCG-AL; +59.1%, EFS=3.38), natural air-cooled garments (ACG-Ns; +39.9%, EFS = 1.12), and phase change material cooling garments (PCMCGs; +19.5%, EFS = 1.2). Performance improvement was observed to be positively and linearly correlated to the differences of core temperature increase rate (r = 0.65, p < 0.01) and sweating rate (r = 0.80, p < 0.001) between MCSs and CON. Considering their application in industrial settings, ACG-Cs, LCGs, and HBCG-AL are practical for work, in which workers do not move frequently, whereas ACG-Ns and PCMCGs are more applicable for the majority of occupational workers. Further enhancement of the cooling efficiency of these two cooling strategies should be initiated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental and Numerical Analysis of the Cooling Performance of Water Spraying Systems during a Fire

PubMed Central

Chen, YaoHan; Su, ChungHwei; Tseng, JoMing; Li, WunJie

2015-01-01

The water spray systems are effective protection systems in the confined or unconfined spaces to avoid the damage to building structures since the high temperature when fires occur. NFPA 15 and 502 have suggested respectively that the factories or vehicle tunnels install water spray systems to protect the machinery and structures. This study discussed the cooling effect of water spray systems in experimental and numerical analyses. The actual combustion of woods were compared with the numerical simulations. The results showed that although the flame continued, the cooling effects by water spraying process within 120 seconds were obvious. The results also indicated that the simulation results of the fifth version Fire Dynamics Simulator (FDS) overestimated the space temperature before water spraying in the case of the same water spray system. PMID:25723519

LDR cryogenics

NASA Technical Reports Server (NTRS)

Nast, T.

1988-01-01

A brief summary from the 1985 Large Deployable Reflector (LDR) Asilomar 2 workshop of the requirements for LDR cryogenic cooling is presented. The heat rates are simply the sum of the individual heat rates from the instruments. Consideration of duty cycle will have a dramatic effect on cooling requirements. There are many possible combinations of cooling techniques for each of the three temperatures zones. It is clear that much further system study is needed to determine what type of cooling system is required (He-2, hybrid or mechanical) and what size and power is required. As the instruments, along with their duty cycles and heat rates, become better defined it will be possible to better determine the optimum cooling systems.

A magnetic resonance (MR) microscopy system using a microfluidically cryo-cooled planar coil.

PubMed

Koo, Chiwan; Godley, Richard F; Park, Jaewon; McDougall, Mary P; Wright, Steven M; Han, Arum

2011-07-07

We present the development of a microfluidically cryo-cooled planar coil for magnetic resonance (MR) microscopy. Cryogenically cooling radiofrequency (RF) coils for magnetic resonance imaging (MRI) can improve the signal to noise ratio (SNR) of the experiment. Conventional cryostats typically use a vacuum gap to keep samples to be imaged, especially biological samples, at or near room temperature during cryo-cooling. This limits how close a cryo-cooled coil can be placed to the sample. At the same time, a small coil-to-sample distance significantly improves the MR imaging capability due to the limited imaging depth of planar MR microcoils. These two conflicting requirements pose challenges to the use of cryo-cooling in MR microcoils. The use of a microfluidic based cryostat for localized cryo-cooling of MR microcoils is a step towards eliminating these constraints. The system presented here consists of planar receive-only coils with integrated cryo-cooling microfluidic channels underneath, and an imaging surface on top of the planar coils separated by a thin nitrogen gas gap. Polymer microfluidic channel structures fabricated through soft lithography processes were used to flow liquid nitrogen under the coils in order to cryo-cool the planar coils to liquid nitrogen temperature (-196 °C). Two unique features of the cryo-cooling system minimize the distance between the coil and the sample: (1) the small dimension of the polymer microfluidic channel enables localized cooling of the planar coils, while minimizing thermal effects on the nearby imaging surface. (2) The imaging surface is separated from the cryo-cooled planar coil by a thin gap through which nitrogen gas flows to thermally insulate the imaging surface, keeping it above 0 °C and preventing potential damage to biological samples. The localized cooling effect was validated by simulations, bench testing, and MR imaging experiments. Using this cryo-cooled planar coil system inside a 4.7 Tesla MR system resulted in an average image SNR enhancement of 1.47 ± 0.11 times relative to similar room-temperature coils. This journal is © The Royal Society of Chemistry 2011

A Magnetic Resonance (MR) Microscopy System using a Microfluidically Cryo-Cooled Planar Coil

PubMed Central

Koo, Chiwan; Godley, Richard F.; Park, Jaewon; McDougall, Mary P.; Wright, Steven M.; Han, Arum

2011-01-01

We present the development of a microfluidically cryo-cooled planar coil for magnetic resonance (MR) microscopy. Cryogenically cooling radiofrequency (RF) coils for magnetic resonance imaging (MRI) can improve the signal to noise ratio (SNR) of the experiment. Conventional cryostats typically use a vacuum gap to keep samples to be imaged, especially biological samples, at or near room temperature during cryo-cooling. This limits how close a cryo-cooled coil can be placed to the sample. At the same time, a small coil-to-sample distance significantly improves the MR imaging capability due to the limited imaging depth of planar MR microcoils. These two conflicting requirements pose challenges to the use of cryo-cooling in MR microcoils. The use of a microfluidic based cryostat for localized cryo-cooling of MR microcoils is a step towards eliminating these constraints. The system presented here consists of planar receive-only coils with integrated cryo-cooling microfluidic channels underneath, and an imaging surface on top of the planar coils separated by a thin nitrogen gas gap. Polymer microfluidic channel structures fabricated through soft lithography processes were used to flow liquid nitrogen under the coils in order to cryo-cool the planar coils to liquid nitrogen temperature (−196°C). Two unique features of the cryo-cooling system minimize the distance between the coil and the sample: 1) The small dimension of the polymer microfluidic channel enables localized cooling of the planar coils, while minimizing thermal effects on the nearby imaging surface. 2) The imaging surface is separated from the cryo-cooled planar coil by a thin gap through which nitrogen gas flows to thermally insulate the imaging surface, keeping it above 0°C and preventing potential damage to biological samples. The localized cooling effect was validated by simulations, bench testing, and MR imaging experiments. Using this cryo-cooled planar coil system inside a 4.7 Tesla MR system resulted in an average image SNR enhancement of 1.47 ± 0.11 times relative to similar room-temperature coils. PMID:21603723

Performance and economic enhancement of cogeneration gas turbines through compressor inlet air cooling

NASA Astrophysics Data System (ADS)

Delucia, M.; Bronconi, R.; Carnevale, E.

1994-04-01

Gas turbine air cooling systems serve to raise performance to peak power levels during the hot months when high atmospheric temperatures cause reductions in net power output. This work describes the technical and economic advantages of providing a compressor inlet air cooling system to increase the gas turbine's power rating and reduce its heat rate. The pros and cons of state-of-the-art cooling technologies, i.e., absorption and compression refrigeration, with and without thermal energy storage, were examined in order to select the most suitable cooling solution. Heavy-duty gas turbine cogeneration systems with and without absorption units were modeled, as well as various industrial sectors, i.e., paper and pulp, pharmaceuticals, food processing, textiles, tanning, and building materials. The ambient temperature variations were modeled so the effects of climate could be accounted for in the simulation. The results validated the advantages of gas turbine cogeneration with absorption air cooling as compared to other systems without air cooling.

Measured performance of a 3 ton LiBr absorption water chiller and its effect on cooling system operation

NASA Technical Reports Server (NTRS)

Namkoong, D.

1976-01-01

A three ton lithium bromide absorption water chiller was tested for a number of conditions involving hot water input, chilled water, and the cooling water. The primary influences on chiller capacity were the hot water inlet temperature and the cooling water inlet temperature. One combination of these two parameters extended the output to as much as 125% of design capacity, but no combination could lower the capacity to below 60% of design. A cooling system was conceptually designed so that it could provide several modes of operation. Such flexibility is needed for any solar cooling system to be able to accommodate the varying solar energy collection and the varying building demand. It was concluded that a three-ton absorption water chiller with the kind of performance that was measured can be incorporated into a cooling system such as that proposed, to provide efficient cooling over the specified ranges of operating conditions.

Measured performance of a 3-ton LiBr absorption water chiller and its effect on cooling system operation

NASA Technical Reports Server (NTRS)

Namkoong, D.

1976-01-01

A 3-ton lithium bromide absorption water chiller was tested for a number of conditions involving hot-water input, chilled water, and the cooling water. The primary influences on chiller capacity were the hot water inlet temperature and the cooling water inlet temperature. One combination of these two parameters extended the output to as much as 125% of design capacity, but no combination could lower the capacity to below 60% of design. A cooling system was conceptually designed so that it could provide several modes of operation. Such flexibility is needed for any solar cooling system to be able to accommodate the varying solar energy collection and the varying building demand. It is concluded that a 3-ton absorption water chiller with the kind of performance that was measured can be incorporated into a cooling system such as that proposed, to provide efficient cooling over the specified ranges of operating conditions.

The effects of cooling systems on CO2-lased human enamel.

PubMed

Lian, H J; Lan, W H; Lin, C P

1996-12-01

The thermal effects on dentin during CO2 laser irradiation on human enamel were investigated. To simulate the clinical practice, two cooling methods (air and water spray) were applied immediately after laser exposure, whereas one group without cooling was served as control. Three hundred and sixty uniform tooth blocks were obtained from freshly extracted human third molars. Temperature change measurements were made via electrical thermocouple implanted within the tooth block 2 mm away from the enamel surface. Experimental treatments consisted of lasing without cooling, lasing with 0.5-ml/sec water cooling, and lasing with 15-psi air cooling. Our results indicated that (1) both air- and water-cooling groups could reduce temperature elevation significantly; (2) the larger power energy resulted in the higher temperature elevation. In conclusion, for CO2 laser irradiation on human enamel both water- and air-cooling methods may be effective on prevention of thermal damage of pulp.

Effect of Silver or Copper Nanoparticles-Dispersed Silane Coatings on Biofilm Formation in Cooling Water Systems

PubMed Central

Ogawa, Akiko; Kanematsu, Hideyuki; Sano, Katsuhiko; Sakai, Yoshiyuki; Ishida, Kunimitsu; Beech, Iwona B.; Suzuki, Osamu; Tanaka, Toshihiro

2016-01-01

Biofouling often occurs in cooling water systems, resulting in the reduction of heat exchange efficiency and corrosion of the cooling pipes, which raises the running costs. Therefore, controlling biofouling is very important. To regulate biofouling, we focus on the formation of biofilm, which is the early step of biofouling. In this study, we investigated whether silver or copper nanoparticles-dispersed silane coatings inhibited biofilm formation in cooling systems. We developed a closed laboratory biofilm reactor as a model of a cooling pipe and used seawater as a model for cooling water. Silver or copper nanoparticles-dispersed silane coating (Ag coating and Cu coating) coupons were soaked in seawater, and the seawater was circulated in the laboratory biofilm reactor for several days to create biofilms. Three-dimensional images of the surface showed that sea-island-like structures were formed on silane coatings and low concentration Cu coating, whereas nothing was formed on high concentration Cu coatings and low concentration Ag coating. The sea-island-like structures were analyzed by Raman spectroscopy to estimate the components of the biofilm. We found that both the Cu coating and Ag coating were effective methods to inhibit biofilm formation in cooling pipes. PMID:28773758

Design of conduction cooling system for a high current HTS DC reactor

NASA Astrophysics Data System (ADS)

Dao, Van Quan; Kim, Taekue; Le Tat, Thang; Sung, Haejin; Choi, Jongho; Kim, Kwangmin; Hwang, Chul-Sang; Park, Minwon; Yu, In-Keun

2017-07-01

A DC reactor using a high temperature superconducting (HTS) magnet reduces the reactor’s size, weight, flux leakage, and electrical losses. An HTS magnet needs cryogenic cooling to achieve and maintain its superconducting state. There are two methods for doing this: one is pool boiling and the other is conduction cooling. The conduction cooling method is more effective than the pool boiling method in terms of smaller size and lighter weight. This paper discusses a design of conduction cooling system for a high current, high temperature superconducting DC reactor. Dimensions of the conduction cooling system parts including HTS magnets, bobbin structures, current leads, support bars, and thermal exchangers were calculated and drawn using a 3D CAD program. A finite element method model was built for determining the optimal design parameters and analyzing the thermo-mechanical characteristics. The operating current and inductance of the reactor magnet were 1,500 A, 400 mH, respectively. The thermal load of the HTS DC reactor was analyzed for determining the cooling capacity of the cryo-cooler. The study results can be effectively utilized for the design and fabrication of a commercial HTS DC reactor.

Adiabatic cooling processes in frustrated magnetic systems with pyrochlore structure

NASA Astrophysics Data System (ADS)

Jurčišinová, E.; Jurčišin, M.

2017-11-01

We investigate in detail the process of adiabatic cooling in the framework of the exactly solvable antiferromagnetic spin-1/2 Ising model in the presence of the external magnetic field on an approximate lattice with pyrochlore structure. The behavior of the entropy of the model is studied and exact values of the residual entropies of all ground states are found. The temperature variation of the system under adiabatic (de)magnetization is investigated and the central role of the macroscopically degenerated ground states in cooling processes is explicitly demonstrated. It is shown that the model parameter space of the studied geometrically frustrated system is divided into five disjunct regions with qualitatively different processes of the adiabatic cooling. The effectiveness of the adiabatic (de)magnetization cooling in the studied model is compared to the corresponding processes in paramagnetic salts. It is shown that the processes of the adiabatic cooling in the antiferromagnetic frustrated systems are much more effective especially in nonzero external magnetic fields. It means that the frustrated magnetic materials with pyrochlore structure can be considered as very promising refrigerants mainly in the situations with nonzero final values of the magnetic field.

Adiabatic cooling processes in frustrated magnetic systems with pyrochlore structure.

PubMed

Jurčišinová, E; Jurčišin, M

2017-11-01

We investigate in detail the process of adiabatic cooling in the framework of the exactly solvable antiferromagnetic spin-1/2 Ising model in the presence of the external magnetic field on an approximate lattice with pyrochlore structure. The behavior of the entropy of the model is studied and exact values of the residual entropies of all ground states are found. The temperature variation of the system under adiabatic (de)magnetization is investigated and the central role of the macroscopically degenerated ground states in cooling processes is explicitly demonstrated. It is shown that the model parameter space of the studied geometrically frustrated system is divided into five disjunct regions with qualitatively different processes of the adiabatic cooling. The effectiveness of the adiabatic (de)magnetization cooling in the studied model is compared to the corresponding processes in paramagnetic salts. It is shown that the processes of the adiabatic cooling in the antiferromagnetic frustrated systems are much more effective especially in nonzero external magnetic fields. It means that the frustrated magnetic materials with pyrochlore structure can be considered as very promising refrigerants mainly in the situations with nonzero final values of the magnetic field.

Numerical investigations of cooling holes system role in the protection of the walls of a gas turbine combustion chamber

NASA Astrophysics Data System (ADS)

Ben Sik Ali, Ahlem; Kriaa, Wassim; Mhiri, Hatem; Bournot, Philippe

2012-05-01

Numerical simulations in a gas turbine Swirl stabilized combustor were conducted to investigate the effectiveness of a cooling system in the protection of combustor walls. The studied combustion chamber has a high degree of geometrical complexity related to the injection system as well as the cooling system based on a big distribution of small holes (about 3,390 holes) bored on the flame tube walls. Two cases were considered respectively the flame tube without and with its cooling system. The calculations were carried out using the industrial CFD code FLUENT 6.2. The various simulations made it possible to highlight the role of cooling holes in the protection of the flame tube walls against the high temperatures of the combustion products. In fact, the comparison between the results of the two studied cases demonstrated that the walls temperature can be reduced by about 800°C by the mean of cooling holes technique.

Highly porous activated carbon based adsorption cooling system employing difluoromethane and a mixture of pentafluoroethane and difluoromethane

NASA Astrophysics Data System (ADS)

Askalany, Ahmed A.; Saha, Bidyut B.

2017-01-01

This paper presents a simulation for a low-grade thermally powered two-beds adsorption cooling system employing HFC-32 and a mixture of HFC-32 and HFC-125 (HFC-410a) with activated carbon of type Maxsorb III. The present simulation model adopts experimentally measured adsorption isotherms, adsorption kinetics and isosteric heat of adsorption data. Effect of operating conditions (mass flow rate of hot water, driving heat source temperature and evaporator temperature) on the system performance has been studied in detail. The simulation results showed that the system could be powered by low-grade heat source temperature (below 85 °C). AC/HFC-32 and AC/HFC-410a adsorption cooling cycles achieved close specific cooling power and coefficient of performance values of 0.15 kW/kg and 0.3, respectively at a regeneration temperature of 90 °C along with evaporator temperature of 10 °C. The investigated semi continuous adsorption cooling system could produce a cooling power of 9 kW.

Control of mineral scale deposition in cooling systems using secondary-treated municipal wastewater.

PubMed

Li, Heng; Hsieh, Ming-Kai; Chien, Shih-Hsiang; Monnell, Jason D; Dzombak, David A; Vidic, Radisav D

2011-01-01

Secondary-treated municipal wastewater (MWW) is a promising alternative to freshwater as power plant cooling system makeup water, especially in arid regions. A prominent challenge for the successful use of MWW for cooling is potentially severe mineral deposition (scaling) on pipe surfaces. In this study, theoretical, laboratory, and field work was conducted to evaluate the mineral deposition potential of MWW and its deposition control strategies under conditions relevant to power plant cooling systems. Polymaleic acid (PMA) was found to effectively reduce scale formation when the makeup water was concentrated four times in a recirculating cooling system. It was the most effective deposition inhibitor of those studied when applied at 10 mg/L dosing level in a synthetic MWW. However, the deposition inhibition by PMA was compromised by free chlorine added for biogrowth control. Ammonia present in the wastewater suppressed the reaction of the free chlorine with PMA through the formation of chloramines. Monochloramine, an alternative to free chlorine, was found to be less reactive with PMA than free chlorine. In pilot tests, scaling control was more challenging due to the occurrence of biofouling even with effective control of suspended bacteria. Phosphorous-based corrosion inhibitors are not appropriate due to their significant loss through precipitation reactions with calcium. Chemical equilibrium modeling helped with interpretation of mineral precipitation behavior but must be used with caution for recirculating cooling systems, especially with use of MWW, where kinetic limitations and complex water chemistries often prevail. Copyright © 2010 Elsevier Ltd. All rights reserved.

RFQ accelerator tuning system

DOEpatents

Bolie, V.W.

1990-07-03

A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control signal to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in response to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. In an RFQ environment the stable temperature control enables the resonant frequency of the device to be maintained at substantially a predetermined value during transient operations. 3 figs.

RFQ accelerator tuning system

DOEpatents

Bolie, Victor W.

1990-01-01

A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control signal to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in response to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. In an RFQ environment the stable temperature control enables the resonant frequency of the device to be maintained at substantially a predetermined value during transient operations.

Effect of Impacts on the Cooling Rates of Differentiated Planetesimals

NASA Astrophysics Data System (ADS)

Lyons, R. J.; Bowling, T. J.; Ciesla, F. J.; Davison, T. M.; Collins, G. S.

2018-05-01

I have modeled planetismal impacts in the early solar system, following their formation, differentiation, and cooling. I found that small collisions can expose the core, resulting in more than an order of magnitude increase in the cooling rates.

Shaped Recess Flow Control

NASA Technical Reports Server (NTRS)

Shyam, Vikram (Inventor); Poinsatte, Philip (Inventor); Thurman, Douglas (Inventor)

2017-01-01

One or more embodiments of techniques or systems for shaped recess flow control are provided herein. A shaped recess or cavity can be formed on a surface associated with fluid flow. The shaped recess can be configured to create or induce fluid effects, temperature effects, or shedding effects that interact with a free stream or other structures. The shaped recess can be formed at an angle to a free stream flow and may be substantially "V" shaped. The shaped recess can be coupled with a cooling channel, for example. The shaped recess can be upstream or downstream from a cooling channel and aligned in a variety of manners. Due to the fluid effects, shedding effects, and temperature effects created by a shaped recess, lift-off or separation of cooling jets of cooling channels can be mitigated, thereby enhancing film cooling effectiveness.

Preliminary study of TEC application in cooling system

NASA Astrophysics Data System (ADS)

Sulaiman, A. C.; Amin, N. A. M.; Saidon, M. S.; Majid, M. S. A.; Rahman, M. T. A.; Kazim, M. N. F. M.

2017-10-01

Integration of thermoelectric cooling (TEC) within a space cooling system in the lecturer room is studied. The studied area (air conditioned surrounding) is encapsulated with wall, floor, roof, and glass window. TEC module is placed on the glass window. The prototype of the studied compartment is designed using cabin container. The type and number of TEC module are studied and the effects on the cooling performance are analyzed as it is assumed to be tested within an air conditioned lecturer room. The experimental and mathematical modeling of the cooling system developed. It is expected that the mathematical modeling derived from this study will be used to estimate the use of the number of TEC module to be integrated with air conditioner unit where possible.

Control of biological growth in recirculating cooling systems using treated secondary effluent as makeup water with monochloramine.

PubMed

Chien, Shih-Hsiang; Chowdhury, Indranil; Hsieh, Ming-Kai; Li, Heng; Dzombak, David A; Vidic, Radisav D

2012-12-01

Secondary-treated municipal wastewater, an abundant and widely distributed impaired water source, is a promising alternative water source for thermoelectric power plant cooling. However, excessive biological growth is a major challenge associated with wastewater reuse in cooling systems as it can interfere with normal system operation as well as enhance corrosion and scaling problems. Furthermore, possible emission of biological aerosols (e.g., Legionella pneumophila) with the cooling tower drift can lead to public health concerns within the zone of aerosol deposition. In this study, the effectiveness of pre-formed and in-situ-formed monochloramine was evaluated for its ability to control biological growth in recirculating cooling systems using secondary-treated municipal wastewater as the only makeup water source. Bench-scale studies were compared with pilot-scale studies for their ability to predict system behavior under realistic process conditions. Effectiveness of the continuous addition of pre-formed monochloramine and monochloramine formed in-situ through the reaction of free chlorine with ammonia in the incoming water was evaluated in terms of biocide residual and its ability to control both planktonic and sessile microbial populations. Results revealed that monochloramine can effectively control biofouling in cooling systems employing secondary-treated municipal wastewater and has advantages relative to use of free chlorine, but that bench-scale studies seriously underestimate biocide dose and residual requirements for proper control of biological growth in full-scale systems. Pre-formed monochloramine offered longer residence time and more reliable performance than in-situ-formed monochloramine due to highly variable ammonia concentration in the recirculating water caused by ammonia stripping in the cooling tower. Pilot-scale tests revealed that much lower dosing rate was required to maintain similar total chlorine residual when pre-formed monochloramine was used as compared to in-situ-formed monochloramine. Adjustment of biocide dose to maintain monochloramine residual above 3mg/L is needed to achieve successful biological growth control in recirculating cooling systems using secondary-treated municipal effluent as the only source of makeup water. Copyright © 2012 Elsevier Ltd. All rights reserved.

Turbine airfoil cooling system with cooling systems using high and low pressure cooling fluids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsh, Jan H.; Messmann, Stephen John; Scribner, Carmen Andrew

A turbine airfoil cooling system including a low pressure cooling system and a high pressure cooling system for a turbine airfoil of a gas turbine engine is disclosed. In at least one embodiment, the low pressure cooling system may be an ambient air cooling system, and the high pressure cooling system may be a compressor bleed air cooling system. In at least one embodiment, the compressor bleed air cooling system in communication with a high pressure subsystem that may be a snubber cooling system positioned within a snubber. A delivery system including a movable air supply tube may be usedmore » to separate the low and high pressure cooling subsystems. The delivery system may enable high pressure cooling air to be passed to the snubber cooling system separate from low pressure cooling fluid supplied by the low pressure cooling system to other portions of the turbine airfoil cooling system.« less

Supercritical CO2 Power Cycles: Design Considerations for Concentrating Solar Power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neises, Ty; Turchi, Craig

2014-09-01

A comparison of three supercritical CO2 Brayton cycles: the simple cycle, recompression cycle and partial-cooling cycle indicates the partial-cooling cycle is favored for use in concentrating solar power (CSP) systems. Although it displays slightly lower cycle efficiency versus the recompression cycle, the partial-cooling cycle is estimated to have lower total recuperator size, as well as a lower maximum s-CO2 temperature in the high-temperature recuperator. Both of these effects reduce recuperator cost. Furthermore, the partial-cooling cycle provides a larger temperature differential across the turbine, which translates into a smaller, more cost-effective thermal energy storage system. The temperature drop across the turbinemore » (and by extension, across a thermal storage system) for the partial-cooling cycle is estimated to be 23% to 35% larger compared to the recompression cycle of equal recuperator conductance between 5 and 15 MW/K. This reduces the size and cost of the thermal storage system. Simulations by NREL and Abengoa Solar indicate the partial-cooling cycle results in a lower LCOE compared with the recompression cycle, despite the former's slightly lower cycle efficiency. Advantages of the recompression cycle include higher thermal efficiency and potential for a smaller precooler. The overall impact favors the use of a partial-cooling cycle for CSP compared to the more commonly analyzed recompression cycle.« less

Physiological Responses to Microclimate Cooling Used By the Air Soldier Dressed at MOPP 4 in an Extreme Desert Condition: Effects of Six Configurations

DTIC Science & Technology

2012-12-01

USARIEM TECHNICAL REPORT PHYSIOLOGICAL RESPONSES TO MICROCLIMATE COOLING USED BY THE AIR SOLDIER DRESSED AT MOPP 4 IN AN...2012 2. REPORT TYPE 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Physiological Responses to Microclimate Cooling Used By the Air Soldier 5b. GRANT... Microclimate Cooling System MCG HI – Air Warrior Microclimate Cooling Garment Used in High Cooling Configuration MCG LO - Air Warrior Microclimate

Operational Characteristics of Four Commercially Available Personal Cooling Vests

NASA Technical Reports Server (NTRS)

Ku, Yu-Tsuan E.; Montgomery, Leslie D.; Lee, Hank C.; Webbon, Bruce W.; Kliss, Mark (Technical Monitor)

1997-01-01

Personal thermoregulatory systems which provide chest cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to compare the effectiveness of two passive and two active cooling vests, and to measure the body temperature and circulatory changes produced by each cooling vest configuration. The MicroClimate Systems and the Life Enhancement Tech(LET) lightweight liquid cooling vests, the Steele Vest and LET's Zipper Front Garment were used to cool the chest region of 11 male and 10 female subjects (25 to 55 yr.) in this study. Calf, forearm and finger blood flows were measured using a tetrapolar impedance rheograph. The subjects, seated in an upright position at normal room temperature (approx.21 C), were tested for 60 min. with the cooling system operated at its maximum cooling capacity. Blood flows were recorded continuously using a computer data acquisition system with a sampling frequency of 250 Hz. Oral, right and left ear temperatures and cooling system parameters were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; respiration; and an activity index were recorded continuously on a URI Inc. Biolog ambulatory monitor. In general, the male and female subjects' rectal and ear temperature responses to cooling were similar for all vest configurations tested. Oral temperatures during the recovery period were significantly (P<0.05) lower than during the control period, approx.0.2 - 0.5 C, for both men and women wearing any of the four different garments. The corresponding car temperatures were significantly (P<0.05) decreased approx.0.2 - 0.3 C by the end of the recovery period. Compared to the control period, no significant differences were found in rectal temperatures during cooling and recovery periods. These results show that all vest configurations elicit a similar thermal response in both male and female subject groups. However, subject population variance was rather large and may have masked differences between the vests. One vest may prove more effective than another for a given individual, and experience is the only means of determining this.

Auxiliary-cavity-assisted ground-state cooling of an optically levitated nanosphere in the unresolved-sideband regime

NASA Astrophysics Data System (ADS)

Feng, Jin-Shan; Tan, Lei; Gu, Huai-Qiang; Liu, Wu-Ming

2017-12-01

We theoretically analyze the ground-state cooling of an optically levitated nanosphere in the unresolved-sideband regime by introducing a coupled high-quality-factor cavity. On account of the quantum interference stemming from the presence of the coupled cavity, the spectral density of the optical force exerting on the nanosphere gets changed and then the symmetry between the heating and the cooling processes is broken. Through adjusting the detuning of a strong-dissipative cavity mode, one obtains an enhanced net cooling rate for the nanosphere. It is illustrated that the ground-state cooling can be realized in the unresolved sideband regime even if the effective optomechanical coupling is weaker than the frequency of the nanosphere, which can be understood by the picture that the effective interplay of the nanosphere and the auxiliary cavity mode brings the system back to an effective resolved regime. Besides, the coupled cavity refines the dynamical stability of the system.

Physiologic and Functional Responses of MS Patients to Body Cooling Using Commercially Available Cooling Garments

NASA Technical Reports Server (NTRS)

Ku, Yu-Tsuan E.; Montgomery, Leslie D.; Lee, Hank C.; Luna, Bernadette; Webbon, Bruce W.; Mead, Susan C. (Technical Monitor)

1999-01-01

Personal cooling systems are widely used in industrial and aerospace environments to alleviate thermal stress. Increasingly they are also used by heat sensitive multiple sclerosis (HSMS) patients to relieve symptoms and improve quality of life. There are a variety of cooling systems commercially available to the MS community. However, little information is available regarding the comparative physiological changes produced by routine operation of these various systems. The objective of this study was to document and compare the patient response to two passive cooling vests and one active cooling garment. The Life Enhancement Technology, Inc. (LET) lightweight active cooling vest with cap, the MicroClimate Systems (MCS) Change of Phase garment, and the Steele Vest were each used to cool 13 male and 13 female MS subjects (31 to 67 yr.) in this study. The subjects, seated in an upright position at normal room temperature (approximately 22 C), were tested with one of the cooling garments. Oral, fight and left ear temperatures were logged manually every 5 min. An-n, leg, chest and rectal temperatures; heart rate; and respiration were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. Each subject was given a series of subjective and objective evaluation tests before and after cooling. The LET and Steele vests test groups had similar, significant (P less than 0.01) cooling effects on oral and ear canal temperature, which decreased approximately 0.4 C, and 0.3 C, respectively. Core temperature increased (N.S.) with all three vests during cooling. The LET vest produced the coldest (P less than 0.01) skin temperature. Overall, the LET vest provided the most improvement on subjective and objective performance measures. These results show that the garment configurations tested do not elicit a similar thermal response in all MS patients. Cooling with the LET active garment configuration resulted in the lowest body temperatures for the MS subjects; cooling with the MCS vest was least effective. For functional responses, the LET test group performed better than the other two vests.

Automatic design of conformal cooling channels in injection molding tooling

NASA Astrophysics Data System (ADS)

Zhang, Yingming; Hou, Binkui; Wang, Qian; Li, Yang; Huang, Zhigao

2018-02-01

The generation of cooling system plays an important role in injection molding design. A conformal cooling system can effectively improve molding efficiency and product quality. This paper provides a generic approach for building conformal cooling channels. The centrelines of these channels are generated in two steps. First, we extract conformal loops based on geometric information of product. Second, centrelines in spiral shape are built by blending these loops. We devise algorithms to implement the entire design process. A case study verifies the feasibility of this approach.

Model validation using CFD-grade experimental database for NGNP Reactor Cavity Cooling Systems with water and air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manera, Annalisa; Corradini, Michael; Petrov, Victor

This project has been focused on the experimental and numerical investigations of the water-cooled and air-cooled Reactor Cavity Cooling System (RCCS) designs. At this aim, we have leveraged an existing experimental facility at the University of Wisconsin-Madison (UW), and we have designed and built a separate effect test facility at the University of Michigan. The experimental facility at UW has underwent several upgrades, including the installation of advanced instrumentation (i.e. wire-mesh sensors) built at the University of Michigan. These provides highresolution time-resolved measurements of the void-fraction distribution in the risers of the water-cooled RCCS facility. A phenomenological model has beenmore » developed to assess the water cooled RCCS system stability and determine the root cause behind the oscillatory behavior that occurs under normal two-phase operation. Testing under various perturbations to the water-cooled RCCS facility have resulted in changes in the stability of the integral system. In particular, the effects on stability of inlet orifices, water tank volume have and system pressure been investigated. MELCOR was used as a predictive tool when performing inlet orificing tests and was able to capture the Density Wave Oscillations (DWOs) that occurred upon reaching saturation in the risers. The experimental and numerical results have then been used to provide RCCS design recommendations. The experimental facility built at the University of Michigan was aimed at the investigation of mixing in the upper plenum of the air-cooled RCCS design. The facility has been equipped with state-of-theart high-resolution instrumentation to achieve so-called CFD grade experiments, that can be used for the validation of Computational Fluid Dynanmics (CFD) models, both RANS (Reynold-Averaged) and LES (Large Eddy Simulations). The effect of risers penetration in the upper plenum has been investigated as well.« less

The effects of regeneration temperature of the desiccant wheel on the performance of desiccant cooling cycles for greenhouse thermally insulated

NASA Astrophysics Data System (ADS)

Rjibi, Amel; Kooli, Sami; Guizani, Amenaallah

2018-05-01

The use of solar energy for cooling greenhouses in the hot period in Mediterranean climate is an important issue. Desiccant evaporative cooling (DEC) system is advantageous because it uses a low grade thermal energy and preserves the merits to be friendly environmentally technology. In this paper, a numerical investigation was carried out on a desiccant cooling system powered by air solar collectors coupled to an insulated greenhouse. The influence of the regeneration temperature on the air stream properties at every system component state point was studied. The performance of the desiccant cooling system was evaluated in terms of thermal and electric coefficient of performance. Results show that the best performance of the system (COPel = 14 and COPth = 0.94) was obtained for a 60 °C regeneration temperature and a supply flow rate ratio of 0.2. An economic analysis shows that the use of the DEC system for greenhouse cooling is attractive and profitable since the payback period is 1 years. The use of the proposed system allows saving 9396 kWh/year of electric energy compared to conventional system.

Unsteady, Cooled Turbine Simulation Using a PC-Linux Analysis System

NASA Technical Reports Server (NTRS)

List, Michael G.; Turner, Mark G.; Chen, Jen-Pimg; Remotigue, Michael G.; Veres, Joseph P.

2004-01-01

The fist stage of the high-pressure turbine (HPT) of the GE90 engine was simulated with a three-dimensional unsteady Navier-Sokes solver, MSU Turbo, which uses source terms to simulate the cooling flows. In addition to the solver, its pre-processor, GUMBO, and a post-processing and visualization tool, Turbomachinery Visual3 (TV3) were run in a Linux environment to carry out the simulation and analysis. The solver was run both with and without cooling. The introduction of cooling flow on the blade surfaces, case, and hub and its effects on both rotor-vane interaction as well the effects on the blades themselves were the principle motivations for this study. The studies of the cooling flow show the large amount of unsteadiness in the turbine and the corresponding hot streak migration phenomenon. This research on the GE90 turbomachinery has also led to a procedure for running unsteady, cooled turbine analysis on commodity PC's running the Linux operating system.

Effect of Thermoelectric Cooling (TEC) module and the water flow heatsink on Photovoltaic (PV) panel performance

NASA Astrophysics Data System (ADS)

Amelia, A. R.; Jusoh, MA; Shamira Idris, Ida

2017-11-01

Photovoltaic (PV) panel suffers in low conversion efficiency of the output performance affected by the elevated operating temperature of the PV panel. It is important to keep the PV panel to operate at low temperature. To address this issue, this paper proposes the cooling system using thermoelectric cooling (TEC) and water block heatsink for enhancing the PV panel output performance. These both types cooling system were designed located on the back side of the PV panel to cool down the operating temperature of the PV panel. To evaluate the function for the existing cooling systems, the experiment was subsequently performed for PV panel without and with different design of the cooling system in outdoor weather conditions. By comparing the experimental results, it is concluded that by the hybrid cooling system which combining TEC module and the water block heatsink could improve the output performance of the PV panel. By the reduction temperature of the PV panel by 16.04 %, the average output power of the PV panel has been boosted up from 8.59 W to 9.03 W. In short, the output power of the PV panel was enhanced by the reduction of the operating temperature of the PV panel.

Investigation of a para-ortho hydrogen reactor for application to spacecraft sensor cooling

NASA Technical Reports Server (NTRS)

Nast, T. C.

1983-01-01

The utilization of solid hydrogen in space for sensor and instrument cooling is a very efficient technique for long term cooling or for cooling at high heat rates. The solid hydrogen can provide temperatures as low as 7 to 8 K to instruments. Vapor cooling is utilized to reduce parasitic heat inputs to the 7 to 8 K stage and is effective in providing intermediate cooling for instrument components operating at higher temperatures. The use of solid hydrogen in place of helium may lead to weight reductions as large as a factor of ten and an attendent reduction in system volume. The results of an investigation of a catalytic reactor for use with a solid hydrogen cooling system is presented. Trade studies were performed on several configurations of reactor to meet the requirements of high reactor efficiency with low pressure drop. Results for the selected reactor design are presented for both liquid hydrogen systems operating at near atmospheric pressure and the solid hydrogen cooler operating as low as 1 torr.

Automatic Incubator-type Temperature Control System for Brain Hypothermia Treatment

NASA Astrophysics Data System (ADS)

Gaohua, Lu; Wakamatsu, Hidetoshi

An automatic air-cooling incubator is proposed to replace the manual water-cooling blanket to control the brain tissue temperature for brain hypothermia treatment. Its feasibility is theoretically discussed as follows: First, an adult patient with the cooling incubator is modeled as a linear dynamical patient-incubator biothermal system. The patient is represented by an 18-compartment structure and described by its state equations. The air-cooling incubator provides almost same cooling effect as the water-cooling blanket, if a light breeze of speed around 3 m/s is circulated in the incubator. Then, in order to control the brain temperature automatically, an adaptive-optimal control algorithm is adopted, while the patient-blanket therapeutic system is considered as a reference model. Finally, the brain temperature of the patient-incubator biothermal system is controlled to follow up the given reference temperature course, in which an adaptive algorithm is confirmed useful for unknown environmental change and/or metabolic rate change of the patient in the incubating system. Thus, the present work ensures the development of the automatic air-cooling incubator for a better temperature regulation of the brain hypothermia treatment in ICU.

Air conditioning system with supplemental ice storing and cooling capacity

DOEpatents

Weng, Kuo-Lianq; Weng, Kuo-Liang

1998-01-01

The present air conditioning system with ice storing and cooling capacity can generate and store ice in its pipe assembly or in an ice storage tank particularly equipped for the system, depending on the type of the air conditioning system. The system is characterized in particular in that ice can be produced and stored in the air conditioning system whereby the time of supplying cooled air can be effectively extended with the merit that the operation cycle of the on and off of the compressor can be prolonged, extending the operation lifespan of the compressor in one aspect. In another aspect, ice production and storage in great amount can be performed in an off-peak period of the electrical power consumption and the stored ice can be utilized in the peak period of the power consumption so as to provide supplemental cooling capacity for the compressor of the air conditioning system whereby the shift of peak and off-peak power consumption can be effected with ease. The present air conditioning system can lower the installation expense for an ice-storing air conditioning system and can also be applied to an old conventional air conditioning system.

Influence of Shading on Cooling Energy Demand

NASA Astrophysics Data System (ADS)

Rabczak, Sławomir; Bukowska, Maria; Proszak-Miąsik, Danuta; Nowak, Krzysztof

2017-10-01

The article presents an analysis of the building cooling load taking into account the variability of the factors affecting the size of the heat gains. In order to minimize the demand for cooling, the effect of shading elements installed on the outside on the windows and its effect on size of the cooling capacity of air conditioning system for the building has been estimated. Multivariate building cooling load calculations to determine the size of the reduction in cooling demand has derived. Determination of heat gain from the sun is laborious, but gives a result which reflects the influence of the surface transparent partitions, devices used as sunscreen and its location on the building envelope in relation to the world, as well as to the internal heat gains has great attention in obtained calculation. In this study, included in the balance sheet of solar heat gains are defined in three different shading of windows. Calculating the total demand cooling is made for variants assuming 0% shading baffles transparent, 50% shading baffles transparent external shutters at an angle of 45 °, 100% shading baffles transparent hours 12 from the N and E and from 12 from the S and W of the outer slat blinds. The calculation of the average hourly cooling load was taken into account the option assuming the hypothetical possibility of default by up to 10% of the time assumed the cooling season temperatures in the rooms. To reduce the consumption of electricity energy in the cooling system of the smallest variant identified the need for the power supply for the operation of the cooling system. Also assessed the financial benefits of the temporary default of comfort.

Analytical Modelling of the Effects of Different Gas Turbine Cooling Techniques on Engine Performance =

NASA Astrophysics Data System (ADS)

Uysal, Selcuk Can

In this research, MATLAB SimulinkRTM was used to develop a cooled engine model for industrial gas turbines and aero-engines. The model consists of uncooled on-design, mean-line turbomachinery design and a cooled off-design analysis in order to evaluate the engine performance parameters by using operating conditions, polytropic efficiencies, material information and cooling system details. The cooling analysis algorithm involves a 2nd law analysis to calculate losses from the cooling technique applied. The model is used in a sensitivity analysis that evaluates the impacts of variations in metal Biot number, thermal barrier coating Biot number, film cooling effectiveness, internal cooling effectiveness and maximum allowable blade temperature on main engine performance parameters of aero and industrial gas turbine engines. The model is subsequently used to analyze the relative performance impact of employing Anti-Vortex Film Cooling holes (AVH) by means of data obtained for these holes by Detached Eddy Simulation-CFD Techniques that are valid for engine-like turbulence intensity conditions. Cooled blade configurations with AVH and other different external cooling techniques were used in a performance comparison study. (Abstract shortened by ProQuest.).

Effect of air velocity on laying hen performance and egg quality

USDA-ARS?s Scientific Manuscript database

Increasing convective cooling can improve performance and thermal comfort of commercial poultry when weather or system design limit cooling through other means such as evaporative cooling. Previous work in young hens showed increased egg production rate as feed intake is maintained under heat stres...

A pump driving liquid cooling circuit method for the aperture of an infrared cold optical system

NASA Astrophysics Data System (ADS)

Xie, RongJian

2017-06-01

To enhance the optical recognition and wavelength filtering of an infrared cold optical system, some lens need to be maintained within a certain temperature range, which requires specific thermal management of the aperture. A 250K liquid cooling circuit designed for this purpose is introduced, and the experimental results established and operated in a vacuum environmental simulation chamber is carried out and analyzed. A practical cooling power source of radiation cooling equipment is adopted and the sun exposure heat load is imitated by array of planar membrane heaters attached on the specific designed structure of the aperture. Controlling the aperture temperature and improving the optical system performance are proved effective. Numerical optimization of the cooling circuit and simulation of the aperture are performed , and the factors affect the optical system performance in the mean time are also investigated.

A study of cooling time reduction of interferometric cryogenic gravitational wave detectors using a high-emissivity coating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakakibara, Y.; Yamamoto, K.; Chen, D.

In interferometric cryogenic gravitational wave detectors, there are plans to cool mirrors and their suspension systems (payloads) in order to reduce thermal noise, that is, one of the fundamental noise sources. Because of the large payload masses (several hundred kg in total) and their thermal isolation, a cooling time of several months is required. Our calculation shows that a high-emissivity coating (e.g. a diamond-like carbon (DLC) coating) can reduce the cooling time effectively by enhancing radiation heat transfer. Here, we have experimentally verified the effect of the DLC coating on the reduction of the cooling time.

Solid oxide fuel cell/gas turbine trigeneration system for marine applications

NASA Astrophysics Data System (ADS)

Tse, Lawrence Kar Chung; Wilkins, Steven; McGlashan, Niall; Urban, Bernhard; Martinez-Botas, Ricardo

2011-03-01

Shipping contributes 4.5% to global CO2 emissions and is not covered by the Kyoto Agreement. One method of reducing CO2 emissions on land is combined cooling heating and power (CCHP) or trigeneration, with typical combined thermal efficiencies of over 80%. Large luxury yachts are seen as an ideal entry point to the off-shore market for this developing technology considering its current high cost. This paper investigates the feasibility of combining a SOFC-GT system and an absorption heat pump (AHP) in a trigeneration system to drive the heating ventilation and air conditioning (HVAC) and electrical base-load systems. A thermodynamic model is used to simulate the system, with various configurations and cooling loads. Measurement of actual yacht performance data forms the basis of this system simulation. It is found that for the optimum configuration using a double effect absorption chiller in Ship 1, the net electric power increases by 47% relative to the electrical power available for a conventional SOFC-GT-HVAC system. This is due to more air cooled to a lower temperature by absorption cooling; hence less electrical cooling by the conventional HVAC unit is required. The overall efficiency is 12.1% for the conventional system, 34.9% for the system with BROAD single effect absorption chiller, 43.2% for the system with double effect absorption chiller. This shows that the overall efficiency of a trigeneration system is far higher when waste heat recovery happens. The desiccant wheel hardly reduces moisture from the outdoor air due to a relative low mass flow rate of fuel cell exhaust available to dehumidify a very large mass flow rate of HVAC air, Hence, desiccant wheel is not recommended for this application.

A simulation for predicting potential cooling effect on LPG-fuelled vehicles

NASA Astrophysics Data System (ADS)

Setiyo, M.; Soeparman, S.; Wahyudi, S.; Hamidi, N.

2016-03-01

Liquefied Petroleum Gas vehicles (LPG Vehicles) provide a potential cooling effect about 430 kJ/kg LPG consumption. This cooling effect is obtained from the LPG phase change from liquid to vapor in the vaporizer. In the existing system, energy to evaporate LPG is obtained from the coolant which is circulated around the vaporizer. One advantage is that the LPG (70/30 propane / butane) when expanded from 8 bar to at 1.2 bar, the temperature is less than -25 °C. These conditions provide opportunities to evaporate LPG with ambient air flow, then produce a cooling effect for cooling car's cabin. In this study, some LPG mix was investigated to determine the optimum condition. A simulation was carried out to estimate potential cooling effects of 2000 cc engine from 1000 rpm to 6000 rpm. In this case, the mass flow rate of LPG is a function of fuel consumption. The simulation result shows that the LPG (70/30 propane/butane) provide the greatest cooling effect compared with other mixtures. In conclusion, the 2000 cc engine fueled LPG at 3000 rpm provides potential cooling effect more than 1.3 kW, despite in the low engine speed (1000 rpm) only provides about 0.5 kW.

Physiologic Responses Produced by Active and Passive Personal Cooling Vests

NASA Technical Reports Server (NTRS)

Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Luna, Bernadette

2000-01-01

Personal thermoregulatory systems which provide chest cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to document and compare the subjects' response to three cooling vests in their recommended configurations. The Life Enhancement Tech (LET) lightweight active cooling vest with cap, the MicroClimate Systems Change of Phase garment (MCS), and the Steele Vest were each used to cool the chest regions of 12 male and 8 female Healthy subjects (21 to 69 yr.) in this study. The subjects, seated in an upright position at normal room temperature (approx. 22 C), were tested for 60 min. with one of the cooling garments. The LET active garment had an initial coolant fluid inlet temperature of 60 F, and was ramped down to 50 F. Oral, right and left ear canal temperatures were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; and respiration were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. For men, all three vests had similar, significant cooling effects. Decreases in the average rectal temperature, oral temperature, and ear canal temperatures were approximately 0.2 C, 0.2 C and 0.1 C, respectively. In contrast to the men, the female subjects wearing the MCS and Steel vests had similar cooling responses in which the core temperature remained elevated and oral and ear canal temperatures did not drop. The LET active garment cooled most of the female subjects in this study; rectal, oral and ear temperature decreased about 0.2 C, 0.3 C and 0.3 C, respectively. These results show that the garment configurations tested do not elicit a similar thermal response in all subjects. A gender difference is evident. The LET active garment configuration was most effective in decreasing temperatures of the female subjects; the MCS vest was least effective. For male subjects, the three vests appear to be more nearly equivalent. The active garment system under study included a cooling cap, which may account for some of the difference in response.

Measure Guideline: Ventilation Cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springer, D.; Dakin, B.; German, A.

2012-04-01

The purpose of this measure guideline on ventilation cooling is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

Nonequilibrium thermodynamics of the Markovian Mpemba effect and its inverse

PubMed Central

Raz, Oren

2017-01-01

Under certain conditions, it takes a shorter time to cool a hot system than to cool the same system initiated at a lower temperature. This phenomenon—the “Mpemba effect”—was first observed in water and has recently been reported in other systems. Whereas several detail-dependent explanations were suggested for some of these observations, no common underlying mechanism is known. Using the theoretical framework of nonequilibrium thermodynamics, we present a widely applicable mechanism for a similar effect, the Markovian Mpemba effect, derive a sufficient condition for its appearance, and demonstrate it explicitly in three paradigmatic systems: the Ising model, diffusion dynamics, and a three-state system. In addition, we predict an inverse Markovian Mpemba effect in heating: Under proper conditions, a cold system can heat up faster than the same system initiated at a higher temperature. We numerically demonstrate that this inverse effect is expected in a 1D antiferromagnet nearest-neighbors interacting Ising chain in the presence of an external magnetic field. Our results shed light on the mechanism behind anomalous heating and cooling and suggest that it should be possible to observe these in a variety of systems. PMID:28461467

Coolant effectiveness in dental cutting with air-turbine handpieces.

PubMed

Leung, Brian T W; Dyson, John E; Darvell, Brian W

2012-03-01

To establish a strategy for evaluating coolant effectiveness and to compare typical cooling conditions used in dental cutting. A test system comprising a resistive heat source and an array of four type K thermocouples was used to compare the cooling effectiveness of air alone, water stream alone, and an air-water spray, as delivered by representative air-turbine handpieces. Mean temperature change at the four sites was recorded for a range of water flow rates in the range 10 to 90 mL min(-1), with and without air, and with and without the turbine running. The thermal resistance of the system, R, was calculated as the temperature change per watt (KW(-1)). For wet cooling (water stream and air-water spray), R was 5.1 to 11.5 KW(-1), whereas for air coolant alone the range was 18.5 to 30.7 KW(-1). R for air-water spray was lower than for water stream cooling at the same flow rate. The thermal resistivity approach is a viable means of comparative testing of cooling efficacy in simulated dental cutting. It may provide a reliable means of testing handpiece nozzle design, thus enabling the development of more efficient cooling.

Solar energy system installed at the North Georgia APDC office building

NASA Technical Reports Server (NTRS)

1979-01-01

A hydronic, automatic drain-down solar heating and cooling system is described. The system provides solar heat exchange from a 2,001 square foot effective collector area and supplies 65-70 percent of the building's cooling demand, 90-95 percent of the heating demand, and domestic hot water. The acceptance test plan and results, system operation and maintenance, and predicted system performance are presented.

Energy Integrated Design of Lighting, Heating, and Cooling Systems, and Its Effect on Building Energy Requirements.

ERIC Educational Resources Information Center

Meckler, Gershon

Comments on the need for integrated design of lighting, heating, and cooling systems. In order to eliminate the penalty of refrigerating the lighting heat, minimize the building non-usable space, and optimize the total energy input, a "systems approach" is recommended. This system would employ heat-recovery techniques based on the ability of the…

Performance analysis and optimization of power plants with gas turbines

NASA Astrophysics Data System (ADS)

Besharati-Givi, Maryam

The gas turbine is one of the most important applications for power generation. The purpose of this research is performance analysis and optimization of power plants by using different design systems at different operation conditions. In this research, accurate efficiency calculation and finding optimum values of efficiency for design of chiller inlet cooling and blade cooled gas turbine are investigated. This research shows how it is possible to find the optimum design for different operation conditions, like ambient temperature, relative humidity, turbine inlet temperature, and compressor pressure ratio. The simulated designs include the chiller, with varied COP and fogging cooling for a compressor. In addition, the overall thermal efficiency is improved by adding some design systems like reheat and regenerative heating. The other goal of this research focuses on the blade-cooled gas turbine for higher turbine inlet temperature, and consequently, higher efficiency. New film cooling equations, along with changing film cooling effectiveness for optimum cooling air requirement at the first-stage blades, and an internal and trailing edge cooling for the second stage, are innovated for optimal efficiency calculation. This research sets the groundwork for using the optimum value of efficiency calculation, while using inlet cooling and blade cooling designs. In the final step, the designed systems in the gas cycles are combined with a steam cycle for performance improvement.

Effectiveness of a night radiative cooling system in different geographical latitudes

NASA Astrophysics Data System (ADS)

Tsoy, A. P.; Granovskiy, A. S.; Baranenko, A. V.; Tsoy, D. A.

2017-08-01

Growth of world energy consumption and depletion of energy resources make humanity to constantly work on the creation of the energy efficient technologies and increase usage of the alternative and renewable sources of energy. One of such alternative sources of energy is the night radiative cooling (NRC). NRC is an alternative and renewable source of energy, derived from the effective radiation of the Earth into the Space. If the given surface is located so that it looks to the night sky, then under the particular condition more energy can be generated under the effect of radiative cooling, than received from the atmosphere. As a result the temperature of the surface can be kept lower than the temperature of the ambient air. This effect can be used for creation of the refrigeration systems with the low energy consumption and as a result lower negative influence on the environment. During the research it has been identified that the possibility of the NRC usage is mostly predetermined by the specifics of the climate of the each region. In particular climate conditions the refrigeration systems working on night radiative cooling will be more effective that in others.

Microfog lubrication for aircraft engine bearings

NASA Technical Reports Server (NTRS)

Rosenlieb, J. W.

1976-01-01

An analysis and system study was performed to provide design information regarding lubricant and coolant flow rates and flow paths for effective utilization of the lubricant and coolant in a once through bearing oil mist (microfog) and coolant air system. Both static and dynamic tests were performed. Static tests were executed to evaluate and calibrate the mist supply system. A total of thirteen dynamic step speed bearing tests were performed using four different lubricants and several different mist and air supply configurations. The most effective configuration consisted of supplying the mist and the major portion of the cooling air axially through the bearing. The results of these tests have shown the feasibility of using a once through oil mist and cooling air system to lubricate and cool a high speed, high temperature aircraft engine mainshaft bearing.

Thermal conductivity anisotropy in holey silicon nanostructures and its impact on thermoelectric cooling

NASA Astrophysics Data System (ADS)

Ren, Zongqing; Lee, Jaeho

2018-01-01

Artificial nanostructures have improved prospects of thermoelectric systems by enabling selective scattering of phonons and demonstrating significant thermal conductivity reductions. While the low thermal conductivity provides necessary temperature gradients for thermoelectric conversion, the heat generation is detrimental to electronic systems where high thermal conductivity are preferred. The contrasting needs of thermal conductivity are evident in thermoelectric cooling systems, which call for a fundamental breakthrough. Here we show a silicon nanostructure with vertically etched holes, or holey silicon, uniquely combines the low thermal conductivity in the in-plane direction and the high thermal conductivity in the cross-plane direction, and that the anisotropy is ideal for lateral thermoelectric cooling. The low in-plane thermal conductivity due to substantial phonon boundary scattering in small necks sustains large temperature gradients for lateral Peltier junctions. The high cross-plane thermal conductivity due to persistent long-wavelength phonons effectively dissipates heat from a hot spot to the on-chip cooling system. Our scaling analysis based on spectral phonon properties captures the anisotropic size effects in holey silicon and predicts the thermal conductivity anisotropy ratio up to 20. Our numerical simulations demonstrate the thermoelectric cooling effectiveness of holey silicon is at least 30% greater than that of high-thermal-conductivity bulk silicon and 400% greater than that of low-thermal-conductivity chalcogenides; these results contrast with the conventional perception preferring either high or low thermal conductivity materials. The thermal conductivity anisotropy is even more favorable in laterally confined systems and will provide effective thermal management solutions for advanced electronics.

Thermal conductivity anisotropy in holey silicon nanostructures and its impact on thermoelectric cooling.

PubMed

Ren, Zongqing; Lee, Jaeho

2018-01-26

Artificial nanostructures have improved prospects of thermoelectric systems by enabling selective scattering of phonons and demonstrating significant thermal conductivity reductions. While the low thermal conductivity provides necessary temperature gradients for thermoelectric conversion, the heat generation is detrimental to electronic systems where high thermal conductivity are preferred. The contrasting needs of thermal conductivity are evident in thermoelectric cooling systems, which call for a fundamental breakthrough. Here we show a silicon nanostructure with vertically etched holes, or holey silicon, uniquely combines the low thermal conductivity in the in-plane direction and the high thermal conductivity in the cross-plane direction, and that the anisotropy is ideal for lateral thermoelectric cooling. The low in-plane thermal conductivity due to substantial phonon boundary scattering in small necks sustains large temperature gradients for lateral Peltier junctions. The high cross-plane thermal conductivity due to persistent long-wavelength phonons effectively dissipates heat from a hot spot to the on-chip cooling system. Our scaling analysis based on spectral phonon properties captures the anisotropic size effects in holey silicon and predicts the thermal conductivity anisotropy ratio up to 20. Our numerical simulations demonstrate the thermoelectric cooling effectiveness of holey silicon is at least 30% greater than that of high-thermal-conductivity bulk silicon and 400% greater than that of low-thermal-conductivity chalcogenides; these results contrast with the conventional perception preferring either high or low thermal conductivity materials. The thermal conductivity anisotropy is even more favorable in laterally confined systems and will provide effective thermal management solutions for advanced electronics.

Cooling System to Treat Exercise-Induced Hyperthermia

DTIC Science & Technology

2016-06-01

temperatures . Additionally, individual variations in sweat rates, ventilation rates, fitness levels, and oxygen consumption were not...gastrointestinal MHR maximum heart rate NASA National Aeronautics and Space Administration Tc core temperature UCHS uncompensated heat stress VO2peak peak oxygen consumption ...the effectiveness of a cooling pump based patient thermal management system supplied by Aspen Systems on lowering core body temperature

Effect of Cooling Units on the Performance of an Automotive Exhaust-Based Thermoelectric Generator

NASA Astrophysics Data System (ADS)

Su, C. Q.; Zhu, D. C.; Deng, Y. D.; Wang, Y. P.; Liu, X.

2017-05-01

Currently, automotive exhaust-based thermoelectric generators (AETEGs) are a hot topic in energy recovery. In order to investigate the influence of coolant flow rate, coolant flow direction and cooling unit arrangement in the AETEG, a thermoelectric generator (TEG) model and a related test bench are constructed. Water cooling is adopted in this study. Due to the non-uniformity of the surface temperature of the heat source, the coolant flow direction would affect the output performance of the TEG. Changing the volumetric flow rate of coolant can increase the output power of multi-modules connected in series or/and parallel as it can improve the temperature uniformity of the cooling unit. Since the temperature uniformity of the cooling unit has a strong influence on the output power, two cooling units are connected in series or parallel to research the effect of cooling unit arrangements on the maximum output power of the TEG. Experimental and theoretical analyses reveal that the net output power is generally higher with cooling units connected in parallel than cooling units connected in series in the cooling system with two cooling units.

Effect of consecutive cooling and immobilization on catecholamine metabolism in rat tissues

NASA Technical Reports Server (NTRS)

Matlina, E. S.; Waysman, S. M.; Zaydner, I. G.; Kogan, B. M.; Nozdracheva, L. V.

1979-01-01

The combined effect of two stressor stimuli--cooling and immobilization--acting successively on the sympathetic-adrenaline system was studied experimentally in rats that were cooled for 8 hours at 7 C on the first day and immobilized for 6 hours on the next day. The biochemical and histochemical methods used and the experimental technique involved are described in detail. The following conclusions were formulated: (1) the successive action of cooling and immobilization results in a stronger decrease in the adrenaline and noradrenaline content in the adrenal gland than that which could be due to a simple summation of the cooling and immobilization effects; (2) successive cooling and immobilization are followed by activation of catecholamine synthesis in the adrenal gland; and (3) 1-DOPA administration (45 mg/kg 3 times in 2 days) intraabdominally activated catecholamine synthesis in the adrenal glands in both the control and test animals.

Experimental temperature analysis of simple & hybrid earth air tunnel heat exchanger in series connection at Bikaner Rajasthan India

NASA Astrophysics Data System (ADS)

Jakhar, O. P.; Sharma, Chandra Shekhar; Kukana, Rajendra

2018-05-01

The Earth Air Tunnel Heat Exchanger System is a passive air-conditioning system which has no side effect on earth climate and produces better cooling effect and heating effect comfortable to human body. It produces heating effect in winter and cooling effect in summer with the minimum power consumption of energy as compare to other air-conditioning devices. In this research paper Temperature Analysis was done on the two systems of Earth Air Tunnel Heat Exchanger experimentally for summer cooling purpose. Both the system was installed at Mechanical Engineering Department Government Engineering College Bikaner Rajasthan India. Experimental results concludes that the Average Air Temperature Difference was found as 11.00° C and 16.27° C for the Simple and Hybrid Earth Air Tunnel Heat Exchanger in Series Connection System respectively. The Maximum Air Temperature Difference was found as 18.10° C and 23.70° C for the Simple and Hybrid Earth Air Tunnel Heat Exchanger in Series Connection System respectively. The Minimum Air Temperature Difference was found as 5.20° C and 11.70° C for the Simple and Hybrid Earth Air Tunnel Heat Exchanger in Series Connection System respectively.

Site dependent factors affecting the economic feasibility of solar powered absorption cooling

NASA Technical Reports Server (NTRS)

Bartlett, J. C.

1978-01-01

A procedure was developed to evaluate the cost effectiveness of combining an absorption cycle chiller with a solar energy system. A basic assumption of the procedure is that a solar energy system exists for meeting the heating load of the building, and that the building must be cooled. The decision to be made is to either cool the building with a conventional vapor compression cycle chiller or to use the existing solar energy system to provide a heat input to the absorption chiller. Two methods of meeting the cooling load not supplied by solar energy were considered. In the first method, heat is supplied to the absorption chiller by a boiler using fossil fuel. In the second method, the load not met by solar energy is net by a conventional vapor compression chiller. In addition, the procedure can consider waste heat as another form of auxiliary energy. Commercial applications of solar cooling with an absorption chiller were found to be more cost effective than the residential applications. In general, it was found that the larger the chiller, the more economically feasible it would be. Also, it was found that a conventional vapor compression chiller is a viable alternative for the auxiliary cooling source, especially for the larger chillers. The results of the analysis gives a relative rating of the sites considered as to their economic feasibility of solar cooling.

ECOLOGICAL EFFECTS OF AEROSOL DRIFT FROM A SALTWATER COOLING SYSTEM

EPA Science Inventory

The local terrestrial effects of salt aerosol drift from powered spray modules and a mechanical draft cooling tower at Turkey Point, Florida were evaluated through field and controlled exposure studies. Indigenous vegetation, soil and fresh water were sampled over a year long per...

Simulative method for determining the optimal operating conditions for a cooling plate for lithium-ion battery cell modules

NASA Astrophysics Data System (ADS)

Smith, Joshua; Hinterberger, Michael; Hable, Peter; Koehler, Juergen

2014-12-01

Extended battery system lifetime and reduced costs are essential to the success of electric vehicles. An effective thermal management strategy is one method of enhancing system lifetime increasing vehicle range. Vehicle-typical space restrictions favor the minimization of battery thermal management system (BTMS) size and weight, making their production and subsequent vehicle integration extremely difficult and complex. Due to these space requirements, a cooling plate as part of a water-glycerol cooling circuit is commonly implemented. This paper presents a computational fluid dynamics (CFD) model and multi-objective analysis technique for determining the thermal effect of coolant flow rate and inlet temperature in a cooling plate-at a range of vehicle operating conditions-on a battery system, thereby providing a dynamic input for one-dimensional models. Traditionally, one-dimensional vehicular thermal management system models assume a static heat input from components such as a battery system: as a result, the components are designed for a set coolant input (flow rate and inlet temperature). Such a design method is insufficient for dynamic thermal management models and control strategies, thereby compromising system efficiency. The presented approach allows for optimal BMTS design and integration in the vehicular coolant circuit.

When Newton's cooling law doesn't hold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tarnow, E.

1994-01-01

What is the fastest way to cool something If the object is macroscopic it is to lower the surrounding temperature as much as possible and let Newton's cooling law take effect. If we enter the microscopic world where quantum mechanics rules, this procedure may no longer be the best. This is shown in a simple example where we calculate the optimum cooling rate for an asymmetric two-state system.

Effects of Variable Properties in Film Cooled Turbulent Boundary Layers.

DTIC Science & Technology

1986-03-01

34 • . .. . . . ..... -.-.-.-...... ’- % A. TURBINE BLADE COOLING FUNDMENTALS For a given size gas turbine, raising the turbine entry temperature results in a...and film cooling principles as illustrated in Figure 5. Latter stages may employ internal convection cooling solely due to the lower gas temperatures...coordinate system used. Taking a differential element and applying the conservation principles of mass, momentum, and energy; the governing equations are

A lab-based study of subground passive cooling system for indoor temperature control

NASA Astrophysics Data System (ADS)

Chok, Mun-Hong; Chan, Chee-Ming

2017-11-01

Passive cooling is an alternative cooling technique which helps to reduce high energy consumption. Respectively, dredged marine soil (DMS) is either being dumped or disposed as waste materials. Dredging works had resulted high labor cost, therefore reuse DMS as to fill it along the coastal area. In this study, DMS chosen to examine the effectiveness of passive cooling system by model tests. Soil characterization were carried out according to BS1377: Part 2: 1990. Model were made into scale of 3 cm to 1 m. Heat exchange unit consists of three pipe designs namely, parallel, ramp and spiral. Preliminary tests including flow rate test and soil sample selection were done to select the best heat exchange unit to carry out the model test. Model test is classified into 2 conditions, day and night, each condition consists of 4 configurations which the temperature results are determined. The result shows that window left open and fan switched on (WO/FO) recorded the most effective cooling effects, from 29 °C to 27 °C with drop of 6.9 %.

Comparison of immersed liquid and air cooling of NASA's Airborne Information Management System

NASA Technical Reports Server (NTRS)

Hoadley, A. W.; Porter, A. J.

1992-01-01

The Airborne Information Management System (AIMS) is currently under development at NASA Dryden Flight Research Facility. The AIMS is designed as a modular system utilizing surface mounted integrated circuits in a high-density configuration. To maintain the temperature of the integrated circuits within manufacturer's specifications, the modules are to be filled with Fluorinert FC-72. Unlike ground based liquid cooled computers, the extreme range of the ambient pressures experienced by the AIMS requires the FC-72 be contained in a closed system. This forces the latent heat absorbed during the boiling to be released during the condensation that must take within the closed module system. Natural convection and/or pumping carries the heat to the outer surface of the AIMS module where the heat transfers to the ambient air. This paper will present an evaluation of the relative effectiveness of immersed liquid cooling and air cooling of the Airborne Information Management System.

Comparison of immersed liquid and air cooling of NASA's Airborne Information Management System

NASA Astrophysics Data System (ADS)

Hoadley, A. W.; Porter, A. J.

1992-07-01

The Airborne Information Management System (AIMS) is currently under development at NASA Dryden Flight Research Facility. The AIMS is designed as a modular system utilizing surface mounted integrated circuits in a high-density configuration. To maintain the temperature of the integrated circuits within manufacturer's specifications, the modules are to be filled with Fluorinert FC-72. Unlike ground based liquid cooled computers, the extreme range of the ambient pressures experienced by the AIMS requires the FC-72 be contained in a closed system. This forces the latent heat absorbed during the boiling to be released during the condensation that must take within the closed module system. Natural convection and/or pumping carries the heat to the outer surface of the AIMS module where the heat transfers to the ambient air. This paper will present an evaluation of the relative effectiveness of immersed liquid cooling and air cooling of the Airborne Information Management System.

Ultrafast giant magnetic cooling effect in ferromagnetic Co/Pt multilayers.

PubMed

Shim, Je-Ho; Ali Syed, Akbar; Kim, Chul-Hoon; Lee, Kyung Min; Park, Seung-Young; Jeong, Jong-Ryul; Kim, Dong-Hyun; Eon Kim, Dong

2017-10-06

The magnetic cooling effect originates from a large change in entropy by the forced magnetization alignment, which has long been considered to be utilized as an alternative environment-friendly cooling technology compared to conventional refrigeration. However, an ultimate timescale of the magnetic cooling effect has never been studied yet. Here, we report that a giant magnetic cooling (up to 200 K) phenomenon exists in the Co/Pt nano-multilayers on a femtosecond timescale during the photoinduced demagnetization and remagnetization, where the disordered spins are more rapidly aligned, and thus magnetically cooled, by the external magnetic field via the lattice-spin interaction in the multilayer system. These findings were obtained by the extensive analysis of time-resolved magneto-optical responses with systematic variation of laser fluence as well as external field strength and direction. Ultrafast giant magnetic cooling observed in the present study can enable a new avenue to the realization of ultrafast magnetic devices.The forced alignment of magnetic moments leads to a large change in entropy, which can be used to reduce the temperature of a material. Here, the authors show that this magnetic cooling effect occurs on a femtosecond time scale in cobalt-platinum nano-multilayers.

Crosswinds Effect on the Thermal Performance of Wet Cooling Towers Under Variable Operating Conditions

NASA Astrophysics Data System (ADS)

Chen, You Liang; Shi, Yong Feng; Hao, Jian Gang; Chang, Hao; Sun, Feng Zhong

2018-01-01

In order to quantitatively analyze the influence of the variable operating parameters on the cooling performance of natural draft wet cooling towers (NDWCTs), a hot model test system was set up with adjustable ambient temperature and humidity, circulating water flowrate and temperature. In order to apply the hot model test results to the real tower, the crosswind Froude number is defined. The results show that the crosswind has a negative effect on the thermal performance of the cooling tower, and there is a critical crosswind velocity corresponding to the lowest cooling efficiency. According to the crosswind Froude number similarity, when the ambient temperature decreases, or the circulating water flowrate and temperature increase, the cooling tower draft force will increase, and the critical crosswind velocity will increase correspondingly.

Heat transfer from an internal combustion (Otto-cycle) engine on the surface of Mars

NASA Technical Reports Server (NTRS)

Gwynne, Owen

1992-01-01

The cooling requirements for an average car sized engine (spark-ignition, V-6, four-stroke, naturally aspirated, about 200 kg, about 100 kW) were looked at for Mars. Several modes of cooling were considered, including forced convection, exhaust, radiation and closed loop systems. The primary goal was to determine the effect of the thinner Martian atmosphere on the cooling system. The results show that there was only a 6-percent difference in the cooling requirements. This difference was due mostly to the thinner atmosphere during forced convection and the heat capacity of the exhaust. A method using a single pass counter-flow heat exchanger is suggested to offset this difference in cooling requirements.

Heat transfer from an internal combustion (Otto-cycle) engine on the surface of Mars

NASA Astrophysics Data System (ADS)

Gwynne, Owen

1992-05-01

The cooling requirements for an average car sized engine (spark-ignition, V-6, four-stroke, naturally aspirated, about 200 kg, about 100 kW) were looked at for Mars. Several modes of cooling were considered, including forced convection, exhaust, radiation and closed loop systems. The primary goal was to determine the effect of the thinner Martian atmosphere on the cooling system. The results show that there was only a 6-percent difference in the cooling requirements. This difference was due mostly to the thinner atmosphere during forced convection and the heat capacity of the exhaust. A method using a single pass counter-flow heat exchanger is suggested to offset this difference in cooling requirements.

Evaluation of a Passive Heat Exchanger Based Cooling System for Fuel Cell Applications

NASA Technical Reports Server (NTRS)

Colozza, Anthony J.; Burke, Kenneth A.

2011-01-01

Fuel cell cooling is conventionally performed with an actively controlled, dedicated coolant loop that exchanges heat with a separate external cooling loop. To simplify this system the concept of directly cooling a fuel cell utilizing a coolant loop with a regenerative heat exchanger to preheat the coolant entering the fuel cell with the coolant exiting the fuel cell was analyzed. The preheating is necessary to minimize the temperature difference across the fuel cell stack. This type of coolant system would minimize the controls needed on the coolant loop and provide a mostly passive means of cooling the fuel cell. The results indicate that an operating temperature of near or greater than 70 C is achievable with a heat exchanger effectiveness of around 90 percent. Of the heat exchanger types evaluated with the same type of fluid on the hot and cold side, a counter flow type heat exchanger would be required which has the possibility of achieving the required effectiveness. The number of heat transfer units required by the heat exchanger would be around 9 or greater. Although the analysis indicates the concept is feasible, the heat exchanger design would need to be developed and optimized for a specific fuel cell operation in order to achieve the high effectiveness value required.

Pressure intelligent control strategy of Waste heat recovery system of converter vapors

NASA Astrophysics Data System (ADS)

Feng, Xugang; Wu, Zhiwei; Zhang, Jiayan; Qian, Hong

2013-01-01

The converter gas evaporative cooling system is mainly used for absorbing heat in the high temperature exhaust gas which produced by the oxygen blowing reaction. Vaporization cooling steam pressure control system of converter is a nonlinear, time-varying, lagging behind, close coupling of multivariable control object. This article based on the analysis of converter operation characteristics of evaporation cooling system, of vaporization in a production run of pipe pressure variation and disturbance factors.For the dynamic characteristics of the controlled objects,we have improved the conventional PID control scheme.In Oxygen blowing process, we make intelligent control by using fuzzy-PID cascade control method and adjusting the Lance,that it can realize the optimization of the boiler steam pressure control.By design simulation, results show that the design has a good control not only ensures drum steam pressure in the context of security, enabling efficient conversion of waste heat.And the converter of 1800 flue gas through pipes and cool and dust removal also can be cooled to about 800. Therefore the converter haze evaporative cooling system has achieved to the converter haze temperature decrease effect and enhanced to the coal gas returns-ratio.

Physiological tolerance to uncompensated heat stress in soldiers: effects of various types of body cooling systems.

PubMed

Jovanović, Dalibor; Karkalić, Radovan; Zeba, Snjezana; Pavlović, Miroslav; Radaković, Sonja S

2014-03-01

In military services, emergency situations when soldiers are exposed to a combination of nuclear, biological and chemical (NBC) contamination combined with heat stress, are frequent and complex. In these specific conditions, usage of personal body cooling systems may be effective in reducing heat stress. The present study was conducted in order to evaluate the efficiency of four various types of contemporary personal body cooling systems based on the "Phase Change Material" (PCM), and its effects on soldiers' subjective comfort and physiological performance during exertional heat stress in hot environments. Ten male soldiers were voluntarily subjected to exertional heat stress tests (EHSTs) consisted of walking on a treadmill (5.5 km/h) in hot conditions (40 degreesC) in climatic chamber, wearing NBC isolating impermeable protective suits. One of the tests was performed without any additional cooling solution (NOCOOL), and four tests were performed while using different types of cooling systems: three in a form of vests and one as underwear. Physiological strain was determined by the mean skin temperature (Tsk), tympanic temperature (Tty), and heart rate values (HR), while sweat rates (SwR) indicated changes in hydration status. In all the cases EHST induced physiological response manifested through increasing Tty, HR and SwR. Compared to NOCOOL tests, when using cooling vests, Tty and Tsk were significantly lower (on 35th min, for 0.44 +/- 0.03 and 0.49 +/- 0.05 degrees C, respectively; p < 0.05), as well as the average SwR (0.17 +/- 0.03 L/m2/h). When using underwear, the values of given parameters were not significantly different compared to NOCOOL tests. Using a body cooling system based on PCM in the form of vest under NBC protective clothes during physical activity in hot conditions, reduces sweating and alleviates heat stress manifested by increased core and skin temperatures and heart rate values. These effects directly improve heat tolerance, hydration state, decrease in the risk of heat illness, and extends the duration of soldiers' exposure to extreme conditions.

Series-parallel solar-augmented rock-bed heat pump. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sowell, E.F.; Othmer, P.W.

1979-12-31

This report deals with a system representing an alternate arrangement of the components in an air-type, heat pump augmented solar heating system. In this system, referred to as Series-Parallel, the heat pump coils are at opposite ends of the rock bed, allowing heating and cooling of the air entering and leaving the bed. This allows a number of unique modes of operation, some of which allow off-peak use of the necessary utility power. Cooling modes are also available, including off-peak cooling-effect storage, night cooling, and free cooling (economizing). The system finds applications principally in single-family residences. The study examined themore » performance of this system at three locations (Sacramento, Albuquerque, and New York) by means of a simulation model. Seasonal heating and cooling performance factors of about 3 were obtained for Albuquerque for the system integrated into a 200 m/sup 2/ residence. Design integration studies suggest an installed cost of approximately $28,000 above a conventional heat pump system using commercially available components. This high cost is largely due to solar hardware, although system complexity also adds. Availability of low-cost air type collectors may make the system attractive. The study also addresses the general problem of predictive control necessary whenever off-peak storage is employed. An algorithm is presented, along with results.« less

Influence of collector heat capacity and internal conditions of heat exchanger on cool-down process of small gas liquefier

NASA Astrophysics Data System (ADS)

Saberimoghaddam, Ali; Bahri Rasht Abadi, Mohammad Mahdi

2018-01-01

Joule-Thomson cooling systems are commonly used in gas liquefaction. In small gas liquefiers, transient cool-down time is high. Selecting suitable conditions for cooling down process leads to decrease in time and cost. In the present work, transient thermal behavior of Joule-Thomson cooling system including counter current helically coiled tube in tube heat exchanger, expansion valve, and collector was studied using experimental tests and simulations. The experiments were performed using small gas liquefier and nitrogen gas as working fluid. The heat exchanger was thermally studied by experimental data obtained from a small gas liquefier. In addition, the simulations were performed using experimental data as variable boundary conditions. A comparison was done between presented and conventional methods. The effect of collector heat capacity and convection heat transfer coefficient inside the tubes on system performance was studied using temperature profiles along the heat exchanger.

Evaluation of two cooling systems under a firefighter coverall.

PubMed

Teunissen, Lennart P J; Wang, Li-Chu; Chou, Shih-Nung; Huang, Chin-Hsien; Jou, Gwo-Tsuen; Daanen, Hein A M

2014-11-01

Firemen often suffer from heat strain. This study investigated two chest cooling systems for use under a firefighting suit. In nine male subjects, a vest with water soaked cooling pads and a vest with water perfused tubes were compared to a control condition. Subjects performed 30 min walking and 10 min recovery in hot conditions, while physiological and perceptual parameters were measured. No differences were observed in heart rate and rectal temperature, but scapular skin temperature and fluid loss were lower using the perfused vest. Thermal sensation was cooler for the perfused vest than for the other conditions, while the cool pad vest felt initially cooler than control. However, comfort and RPE scores were similar. We conclude that the cooling effect of both tested systems, mainly providing a (temporally) cooler thermal sensation, was limited and did not meet the expectations. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Recovery Act: Cedarville School District Retrofit of Heating and Cooling Systems with Geothermal Heat Pumps and Ground Source Water Loops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarrell, Mark

Cedarville School District retrofitted the heating and cooling systems in three campus areas (High School, Middle School, and Upper Elementary School) with geothermal heat pumps and ground source water loops, as a demonstration project for the effective implementation of geothermal heat pump systems and other energy efficiency and air quality improvements.

Experimental study on natural circulation precooling of cryogenic pump system with gas phase inlet reflux configuration

NASA Astrophysics Data System (ADS)

Chen, G. B.; Zhong, Y. K.; Zheng, X. L.; Li, Q. F.; Xie, X. M.; Gan, Z. H.; Huang, Y. H.; Tang, K.; Kong, B.; Qiu, L. M.

2003-12-01

A novel gas-phase inlet configuration in the natural circulation system instead of the liquid-phase inlet is introduced to cool down a cryogenic pump system from room temperature to cryogenic temperatures, effectively. The experimental apparatus is illustrated and test process is described. Heat transfer and pressure drop data during the cool-down process are recorded and portrayed. By contrast with liquid-phase inlet configuration, experimental results demonstrate that the natural circulation with the gas-phase inlet configuration is an easier and more controllable way to cool down the pump system and maintain it at cryogenic temperatures.

Microtextured Surfaces for Turbine Blade Impingement Cooling

NASA Technical Reports Server (NTRS)

Fryer, Jack

2014-01-01

Gas turbine engine technology is constantly challenged to operate at higher combustor outlet temperatures. In a modern gas turbine engine, these temperatures can exceed the blade and disk material limits by 600 F or more, necessitating both internal and film cooling schemes in addition to the use of thermal barrier coatings. Internal convective cooling is inadequate in many blade locations, and both internal and film cooling approaches can lead to significant performance penalties in the engine. Micro Cooling Concepts, Inc., has developed a turbine blade cooling concept that provides enhanced internal impingement cooling effectiveness via the use of microstructured impingement surfaces. These surfaces significantly increase the cooling capability of the impinging flow, as compared to a conventional untextured surface. This approach can be combined with microchannel cooling and external film cooling to tailor the cooling capability per the external heating profile. The cooling system then can be optimized to minimize impact on engine performance.

Multi-Megawatt Power System Trade Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Longhurst, Glen Reed; Schnitzler, Bruce Gordon; Parks, Benjamin Travis

2001-11-01

As part of a larger task, the Idaho National Engineering and Environmental Laboratory (INEEL) was tasked to perform a trade study comparing liquid-metal cooled reactors having Rankine power conversion systems with gas-cooled reactors having Brayton power conversion systems. This report summarizes the approach, the methodology, and the results of that trade study. Findings suggest that either approach has the possibility to approach the target specific mass of 3-5 kg/kWe for the power system, though it appears either will require improvements to achieve that. Higher reactor temperatures have the most potential for reducing the specific mass of gas-cooled reactors but domore » not necessarily have a similar effect for liquid-cooled Rankine systems. Fuels development will be the key to higher reactor operating temperatures. Higher temperature turbines will be important for Brayton systems. Both replacing lithium coolant in the primary circuit with gallium and replacing potassium with sodium in the power loop for liquid systems increase system specific mass. Changing the feed pump turbine to an electric motor in Rankine systems has little effect. Key technologies in reducing specific mass are high reactor and radiator operating temperatures, low radiator areal density, and low turbine/generator system masses. Turbine/generator mass tends to dominate overall power system mass for Rankine systems. Radiator mass was dominant for Brayton systems.« less

Operational Characteristics of Two Commercially Available Personal Cooling Vests

NASA Technical Reports Server (NTRS)

Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Webbon, Bruce W.; Luna, Bernadette (Technical Monitor)

1996-01-01

Personal thermoregulatory systems which provide chest cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to compare the effectiveness of two passive cooling vests, and to measure the body temperature and circulatory changes produced by each cooling vest configuration. A Life Enhancement Technologies, (LET) ice vest garment and a Steele, Inc. vest were used to cool the chest region of 11 male subjects (25 to 55 yr) in this study. Calf, forearm and finger blood flows were measured using a tetrapolar impedance rheograph. The subjects, seated in an upright position at normal room temperature (approximately 21 C) were tested for 60 min. with the cooling system operating at its maximum cooling capacity. Blood flows were recorded continuously using a computer data acquisition system with a sampling frequency of 250 Hz. Oral, right and left ear temperatures and cooling system parameters were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; respiration; and an activity index were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. No significant differences were found in either the oral or ear temperature responses to the two vests. However, the rectal and mean skin temperatures at the end of the cooling period were both significantly lower (P less than 0.05), approximately 0.2 and 1.9 C, respectively for the LET vest than for the Steele garment. These data show that different vest configurations may produce different thermal responses in healthy male subjects which should be considered in the use of these cooling garments.

Liquid over-feeding air conditioning system and method

DOEpatents

Mei, Viung C.; Chen, Fang C.

1993-01-01

A refrigeration air conditioning system utilizing a liquid over-feeding operation is described. A liquid refrigerant accumulator-heat exchanger is placed in the system to provide a heat exchange relationship between hot liquid refrigerant discharged from condenser and a relatively cool mixture of liquid and vaporous refrigerant discharged from the evaporator. This heat exchange relationship substantially sub-cools the hot liquid refrigerant which undergoes little or no evaporation across the expansion device and provides a liquid over-feeding operation through the evaporator for effectively using 100 percent of evaporator for cooling purposes and for providing the aforementioned mixture of liquid and vaporous refrigerant.

Numerical optimization of a multi-jet cooling system for the blown film extrusion

NASA Astrophysics Data System (ADS)

Janas, M.; Wortberg, J.

2015-05-01

The limiting factor for every extrusion process is the cooling. For the blown film process, this task is usually done by means of a single or dual lip air ring. Prior work has shown that two major effects are responsible for a bad heat transfer. The first one is the interaction between the jet and the ambient air. It reduces the velocity of the jet and enlarges the straight flow. The other one is the formation of a laminar boundary layer on the film surface due to the fast flowing cooling air. In this case, the boundary layer isolates the film and prevents an efficient heat transfer. To improve the heat exchange, a novel cooling approach is developed, called Multi-Jet. The new cooling system uses several slit nozzles over the whole tube formation zone for cooling the film. In contrast to a conventional system, the cooling air is guided vertically on the film surface in different heights to penetrate the boundary sublayer. Simultaneously, a housing of the tube formation zone is practically obtained to reduce the interaction with the ambient air. For the numerical optimization of the Multi-Jet system, a new procedure is developed. First, a prediction model identifies a worth considering cooling configuration. Therefore, the prediction model computes a film curve using the formulation from Zatloukal-Vlcek and the energy balance for the film temperature. Thereafter, the optimized cooling geometry is investigated in detail using a process model for the blown film extrusion that is able to compute a realistic bubble behavior depending on the cooling situation. In this paper, the Multi-Jet cooling system is numerically optimized for several different process states, like mass throughputs and blow-up ratios using one slit nozzle setting. For each process condition, the best cooling result has to be achieved. Therefore, the height of any nozzle over the tube formation zone is adjustable. The other geometrical parameters of the cooling system like the nozzle diameter or the nozzle width are fix.

Research on the operation control strategy of the cooling ceiling combined with fresh air system

NASA Astrophysics Data System (ADS)

Huang, Tao; Li, Hao

2018-03-01

The cooling ceiling combined with independent fresh air system was built by TRNSYS. And the cooling effects of the air conditioning system of an office in Beijing in a summer typical day were simulated. Based on the “variable temperature” control strategy, the operation strategy of “variable air volume auxiliary adjustment” was put forward. The variation of the indoor temperature, the indoor humidity, the temperature of supplying water and the temperature of returning water were simulated under the two control strategies. The energy consumption of system during the whole summer was compared by utilizing the two control strategies, and the indoor thermal comfort was analyzed. The optimal control strategy was proposed under the condition that the condensation on the surface of the cooling ceiling is not occurred and the indoor thermal comfort is satisfied.

The effect of atomic response time in the theory of Doppler cooling of trapped ions

NASA Astrophysics Data System (ADS)

Janacek, H.; Steane, A. M.; Lucas, D. M.; Stacey, D. N.

2018-03-01

We describe a simple approach to the problem of incorporating the response time of an atom or ion being Doppler-cooled into the theory of the cooling process. The system being cooled does not in general respond instantly to the changing laser frequencies it experiences in its rest frame, and this 'dynamic effect' can affect significantly the temperatures attainable. It is particularly important for trapped ions when there is a slow decay out of the cooling cycle requiring the use of a repumping beam. We treat the cases of trapped ions with two and three internal states, then apply the theory to ?. For this ion experimental data exist showing the ion to be cold under conditions for which heating is predicted if the dynamic effect is neglected. The present theory accounts for the observed behaviour.

Super cool X-1000 and Super cool Z-1000, two ice blockers, and their effect on vitrification/warming of mouse embryos.

PubMed

Badrzadeh, H; Najmabadi, S; Paymani, R; Macaso, T; Azadbadi, Z; Ahmady, A

2010-07-01

To evaluate the survival and blastocyst formation rates of mouse embryos after vitrification/thaw process with different ice blocker media. We used X-1000 and Z-1000 separately and mixed using V-Kim, a closed vitrification system. Mouse embryos were vitrified using ethylene glycol based medium supplemented with Super cool X-1000 and/or Super cool Z-1000. Survival rates for the control, Super cool X-1000, Super cool Z-1000, and Super cool X-1000/Z-1000 groups were 74%, 72%, 68%, and 85% respectively, with no significant difference among experimental and control groups; however, a significantly higher survival rate was noticed in the Super cool X-1000/Z-1000 group when compared with the Super cool Z-1000 group. Blastocyst formation rates for the control, Super cool X-1000, Super cool Z-1000, and Super cool X-1000/Z-1000 groups were 71%, 66%, 65%, and 72% respectively. There was no significant difference in this rate among control and experimental groups. In a closed vitrification system, addition of ice blocker Super cool X-1000 to the vitrification solution containing Super cool Z-1000 may improve the embryo survival rate. We recommend combined ice blocker usage to optimize the vitrification outcome. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Biomedical Application of Aerospace Personal Cooling Systems

NASA Technical Reports Server (NTRS)

Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Webbon, Bruce W.; Kliss, Mark (Technical Monitor)

1997-01-01

Personal thermoregulatory systems which are used by astronauts to alleviate thermal stress during extravehicular activity have been applied to the therapeutic management of multiple sclerosis. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to compare the effectiveness of two passive and two active cooling vests and to measure the body temperature and circulatory changes produced by each cooling vest configuration. The MicroClimate Systems and the Life Enhancement Tech(LET) lightweight liquid cooling vests, the Steele Vest and LET's Zipper Front Garment were used to cool the chest region of 10 male and female subjects (25 to 55 yr.) in this study. Calf, forearm and finger blood flows were measured using a tetrapolar impedance rheograph. The subjects, seated in an upright position at normal room temperature (approx.22C), were tested for 60 min. with the cooling system operated at its maximum cooling capacity. Blood flows were recorded continuously using a computer data acquisition system with a sampling frequency of 250 Hz. Oral, right and left ear temperatures and cooling system parameters were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; respiration; and an activity index were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. In general, the male and female subjects' oral and ear temperature responses to cooling were similar for all vest configurations tested. Oral temperatures during the recovery period were significantly (P<0.05) lower than during the control period, approx. 0.2 - 0.5C, for both men and women wearing any of the four different garments. The corresponding ear temperatures were significantly (P<0.05) decreased approx.0.2 - 0.4C by the end of the recovery period. Compared to the control period, no significant differences were found in rectal temperatures during cooling and recovery periods.

Experimental investigation on the effects of cooling system on surface quality in high speed milling of an aluminium alloy

NASA Astrophysics Data System (ADS)

Chirita, B.; Tampu, N. C.; Brabie, G.; Radu, M. C.

2016-08-01

Surface quality is often an important feature of industrial products, not only from the impact it has on the aesthetic aspect but also for the functional role of the parts. High quality surface increases corrosion resistance, assures a longer life cycle for the product and lowers the wear. For a machined part, surface quality is influenced by a series of factors such as the material of the part, the process type, tool geometry, cutting parameters or the cooling system. The choice of the cooling system is especially important, taking into account that the proper conditions will not only assure a superior surface quality, but will also lower the costs and reduce the environmental impact and health risks. The present study aims to investigate the performance of the cooling system and the effect of the cutting parameters on the characteristics of the surfaces resulted from high speed face milling of some parts made of Al 7050-T7451 aluminium alloy. Dry cutting conditions and minimum quantity lubrication (MQL) where used. The results were analysed using analysis of variance (ANOVA).

Controlled cooling of an electronic system for reduced energy consumption

DOE Office of Scientific and Technical Information (OSTI.GOV)

David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

Energy efficient control of a cooling system cooling an electronic system is provided. The control includes automatically determining at least one adjusted control setting for at least one adjustable cooling component of a cooling system cooling the electronic system. The automatically determining is based, at least in part, on power being consumed by the cooling system and temperature of a heat sink to which heat extracted by the cooling system is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the coolingmore » system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on one or more experimentally obtained models relating the targeted temperature and power consumption of the one or more adjustable cooling components of the cooling system.« less

A predictive model to evaluate the impact of the cooling profile on growth of psychrotrophic bacteria in raw milk from conventional and robotic milking.

PubMed

Christiansson, Anders

2017-08-01

This Research Communication explores the usefulness of predictive modelling to explain bacterial behaviour during cooling. A simple dynamic lag phase model was developed and validated. The model takes into account the effect of the cooling profile on the lag phase and growth in bulk tank milk. The time before the start of cooling was the most critical and should not exceed 1 h. The cooling rate between 30 and approximately 10 °C was the second most critical period. Cooling from 30 to 10 °C within 2 h ensured minimal growth of psychrotrophic bacteria in the milk. The cooling rate between 10 and 4 °C (the slowest phase of cooling) was of surprisingly little importance. Given a normal cooling profile to 10 °C, several hours of prolonged cooling time made practically no difference in psychrotrophic counts. This behaviour can be explained by the time/temperature dependence of the work needed by the bacteria to complete the lag phase at low temperature. For milk quality advisors, it is important to know that slow cooling below 10 °C does not result in high total counts of bacteria. In practice, slow cooling is occasionally found at farms with robotic milking. However, when comparing psychrotrophic growth in bulk milk tanks designed for robotic milking or conventional milking, the model predicted less growth for robotic milking for identical cooling profiles. It is proposed that due to the different rates of milk entering the tank, fewer bacteria will exit the lag phase during robotic milking and they will be more diluted than in conventional milking systems. At present, there is no international standard that specifies the cooling profile in robotic systems. The information on the insignificant effect of the cooling rate below 10 °C may be useful in the development of a standard.

Revisiting the climate impacts of cool roofs around the globe using an Earth system model

NASA Astrophysics Data System (ADS)

Zhang, Jiachen; Zhang, Kai; Liu, Junfeng; Ban-Weiss, George

2016-08-01

Solar reflective ‘cool roofs’ absorb less sunlight than traditional dark roofs, reducing solar heat gain, and decreasing the amount of heat transferred to the atmosphere. Widespread adoption of cool roofs could therefore reduce temperatures in urban areas, partially mitigating the urban heat island effect, and contributing to reversing the local impacts of global climate change. The impacts of cool roofs on global climate remain debated by past research and are uncertain. Using a sophisticated Earth system model, the impacts of cool roofs on climate are investigated at urban, continental, and global scales. We find that global adoption of cool roofs in urban areas reduces urban heat islands everywhere, with an annual- and global-mean decrease from 1.6 to 1.2 K. Decreases are statistically significant, except for some areas in Africa and Mexico where urban fraction is low, and some high-latitude areas during wintertime. Analysis of the surface and TOA energy budget in urban regions at continental-scale shows cool roofs causing increases in solar radiation leaving the Earth-atmosphere system in most regions around the globe, though the presence of aerosols and clouds are found to partially offset increases in upward radiation. Aerosols dampen cool roof-induced increases in upward solar radiation, ranging from 4% in the United States to 18% in more polluted China. Adoption of cool roofs also causes statistically significant reductions in surface air temperatures in urbanized regions of China (-0.11 ± 0.10 K) and the United States (-0.14 ± 0.12 K); India and Europe show statistically insignificant changes. Though past research has disagreed on whether widespread adoption of cool roofs would cool or warm global climate, these studies have lacked analysis on the statistical significance of global temperature changes. The research presented here indicates that adoption of cool roofs around the globe would lead to statistically insignificant reductions in global mean air temperature (-0.0021 ± 0.026 K). Thus, we suggest that while cool roofs are an effective tool for reducing building energy use in hot climates, urban heat islands, and regional air temperatures, their influence on global climate is likely negligible.

Revisiting the Climate Impacts of Cool Roofs around the Globe Using an Earth System Model

NASA Astrophysics Data System (ADS)

Zhang, J.; Ban-Weiss, G. A.; Zhang, K.; Liu, J.

2016-12-01

Solar reflective "cool roofs" absorb less sunlight than traditional dark roofs, reducing solar heat gain, and decreasing the amount of heat transferred to the atmosphere. Widespread adoption of cool roofs could therefore reduce temperatures in urban areas, partially mitigating the urban heat island effect, and contributing to reversing the local impacts of global climate change. The impacts of cool roofs on global climate remain debated by past research and are uncertain. Using a sophisticated Earth system model, the impacts of cool roofs on climate are investigated at urban, continental, and global scales. We find that global adoption of cool roofs in urban areas reduces urban heat islands everywhere, with an annual- and global-mean decrease from 1.6 to 1.2 K. Decreases are statistically significant, except for some areas in Africa and Mexico where urban fraction is low, and some high-latitude areas during wintertime. Analysis of the surface and TOA energy budget in urban regions at continental-scale shows cool roofs causing increases in solar radiation leaving the Earth-atmosphere system in most regions around the globe, though the presence of aerosols and clouds are found to partially offset increases in upward radiation. Aerosols dampen cool roof-induced increases in upward solar radiation, ranging from 4% in the United States to 18% in more polluted China. Adoption of cool roofs also causes statistically significant reductions in surface air temperatures in urbanized regions of China (-0.11±0.10 K) and the United States (-0.14±0.12 K); India and Europe show statistically insignificant changes. Though past research has disagreed on whether widespread adoption of cool roofs would cool or warm global climate, these studies have lacked analysis on the statistical significance of global temperature changes. The research presented here indicates that adoption of cool roofs around the globe would lead to statistically insignificant reductions in global mean air temperature (-0.0021 ± 0.026 K). Thus, we suggest that while cool roofs are an effective tool for reducing building energy use in hot climates, urban heat islands, and regional air temperatures, their influence on global climate is likely negligible.

Development of a single-phase thermosiphon for cold collection and storage of radiative cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Dongliang; Martini, Christine Elizabeth; Jiang, Siyu

A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facilitymore » was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained have demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers.« less

Fast optical cooling of a nanomechanical cantilever by a dynamical Stark-shift gate.

PubMed

Yan, Leilei; Zhang, Jian-Qi; Zhang, Shuo; Feng, Mang

2015-10-12

The efficient cooling of nanomechanical resonators is essential to exploration of quantum properties of the macroscopic or mesoscopic systems. We propose such a laser-cooling scheme for a nanomechanical cantilever, which works even for the low-frequency mechanical mode and under weak cooling lasers. The cantilever is coupled by a diamond nitrogen-vacancy center under a strong magnetic field gradient and the cooling is assisted by a dynamical Stark-shift gate. Our scheme can effectively enhance the desired cooling efficiency by avoiding the off-resonant and undesired carrier transitions, and thereby cool the cantilever down to the vicinity of the vibrational ground state in a fast fashion.

Fast optical cooling of a nanomechanical cantilever by a dynamical Stark-shift gate

PubMed Central

Yan, Leilei; Zhang, Jian-Qi; Zhang, Shuo; Feng, Mang

2015-01-01

The efficient cooling of nanomechanical resonators is essential to exploration of quantum properties of the macroscopic or mesoscopic systems. We propose such a laser-cooling scheme for a nanomechanical cantilever, which works even for the low-frequency mechanical mode and under weak cooling lasers. The cantilever is coupled by a diamond nitrogen-vacancy center under a strong magnetic field gradient and the cooling is assisted by a dynamical Stark-shift gate. Our scheme can effectively enhance the desired cooling efficiency by avoiding the off-resonant and undesired carrier transitions, and thereby cool the cantilever down to the vicinity of the vibrational ground state in a fast fashion. PMID:26455901

Stirling Air Conditioner for Compact Cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-09-01

BEETIT Project: Infinia is developing a compact air conditioner that uses an unconventional high efficient Stirling cycle system (vs. conventional vapor compression systems) to produce cool air that is energy efficient and does not rely on polluting refrigerants. The Stirling cycle system is a type of air conditioning system that uses a motor with a piston to remove heat to the outside atmosphere using a gas refrigerant. To date, Stirling systems have been expensive and have not had the right kind of heat exchanger to help cool air efficiently. Infinia is using chip cooling technology from the computer industry tomore » make improvements to the heat exchanger and improve system performance. Infinia’s air conditioner uses helium gas as refrigerant, an environmentally benign gas that does not react with other chemicals and does not burn. Infinia’s improvements to the Stirling cycle system will enable the cost-effective mass production of high-efficiency air conditioners that use no polluting refrigerants.« less

46 CFR 153.432 - Cooling systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Cooling systems. 153.432 Section 153.432 Shipping COAST... Control Systems § 153.432 Cooling systems. (a) Each cargo cooling system must have an equivalent standby... cooling system. (b) Each tankship that has a cargo tank with a required cooling system must have a manual...

46 CFR 153.432 - Cooling systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Cooling systems. 153.432 Section 153.432 Shipping COAST... Control Systems § 153.432 Cooling systems. (a) Each cargo cooling system must have an equivalent standby... cooling system. (b) Each tankship that has a cargo tank with a required cooling system must have a manual...

46 CFR 153.432 - Cooling systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Cooling systems. 153.432 Section 153.432 Shipping COAST... Control Systems § 153.432 Cooling systems. (a) Each cargo cooling system must have an equivalent standby... cooling system. (b) Each tankship that has a cargo tank with a required cooling system must have a manual...

46 CFR 153.432 - Cooling systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Cooling systems. 153.432 Section 153.432 Shipping COAST... Control Systems § 153.432 Cooling systems. (a) Each cargo cooling system must have an equivalent standby... cooling system. (b) Each tankship that has a cargo tank with a required cooling system must have a manual...

Some ideas on the choice of designs and materials for cooled mirrors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howells, M.R.

1994-12-01

This paper expresses some views on the fabrication of future synchrotron beam-line optics; more particularly the metallurgical issues in high-quality metal mirrors. A simple mirror with uniform cooling channels is first analyzed theoretically, followed by the cullular-pin-post system with complex coolant flow path. Choice of mirror material is next considered. For the most challenging situations (need for intensive cooling), the present practice is to use nickel-plated glidcop or silicon; for less severe challenges, Si carbide may be used and cooling may be direct or indirect; and for the mildest heat loads, fused silica or ulf are popular. For the highestmore » performance mirrors (extreme heat load), the glidcop developments should be continued perhaps to cellular-pin-post systems. For extreme distortion, Si is indicated and invar offers both improved performance and lower price. For less extreme challenges but still with cooling, Ni-plated metals have the cost advantage and SXA and other Al alloys can be added to glidcop and invar. For mirrors with mild cooling requirements, stainless steel would have many advantages. Once the internal cooling designs are established, they will be seen as more cost-effective and reliable than clamp-on schemes. Where no cooling is needed, Si, Si carbide, and the glasses can be used. For the future, the effect of electroless Ni layers on cooling design need study, and a way to finish nickel that is compatible with multilayers should be developed.« less

A novel personal cooling system (PCS) incorporated with phase change materials (PCMs) and ventilation fans: An investigation on its cooling efficiency.

PubMed

Lu, Yehu; Wei, Fanru; Lai, Dandan; Shi, Wen; Wang, Faming; Gao, Chuansi; Song, Guowen

2015-08-01

Personal cooling systems (PCS) have been developed to mitigate the impact of severe heat stress for humans working in hot environments. It is still a great challenge to develop PCSs that are portable, inexpensive, and effective. We studied the performance of a new hybrid PCS incorporating both ventilation fans and phase change materials (PCMs). The cooling efficiency of the newly developed PCS was investigated on a sweating manikin in two hot conditions: hot humid (HH, 34°C, 75% RH) and hot dry (HD, 34°C, 28% RH). Four test scenarios were selected: fans off with no PCMs (i.e., Fan-off, the CONTROL), fans on with no PCMs (i.e., Fan-on), fans off with fully solidified PCMs (i.e., PCM+Fan-off), and fans on with fully solidified PCMs (i.e., PCM+Fan-on). It was found that the addition of PCMs provided a 54∼78min cooling in HH condition. In contrast, the PCMs only offered a 19-39min cooling in HD condition. In both conditions, the ventilation fans greatly enhanced the evaporative heat loss compared with Fan-off. The hybrid PCS (i.e., PCM+Fan-on) provided a continuous cooling effect during the three-hour test and the average cooling rate for the whole body was around 111 and 315W in HH and HD conditions, respectively. Overall, the new hybrid PCS may be an effective means of ameliorating symptoms of heat stress in both hot-humid and hot-dry environments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coupled reactor kinetics and heat transfer model for heat pipe cooled reactors

NASA Astrophysics Data System (ADS)

Wright, Steven A.; Houts, Michael

2001-02-01

Heat pipes are often proposed as cooling system components for small fission reactors. SAFE-300 and STAR-C are two reactor concepts that use heat pipes as an integral part of the cooling system. Heat pipes have been used in reactors to cool components within radiation tests (Deverall, 1973); however, no reactor has been built or tested that uses heat pipes solely as the primary cooling system. Heat pipe cooled reactors will likely require the development of a test reactor to determine the main differences in operational behavior from forced cooled reactors. The purpose of this paper is to describe the results of a systems code capable of modeling the coupling between the reactor kinetics and heat pipe controlled heat transport. Heat transport in heat pipe reactors is complex and highly system dependent. Nevertheless, in general terms it relies on heat flowing from the fuel pins through the heat pipe, to the heat exchanger, and then ultimately into the power conversion system and heat sink. A system model is described that is capable of modeling coupled reactor kinetics phenomena, heat transfer dynamics within the fuel pins, and the transient behavior of heat pipes (including the melting of the working fluid). This paper focuses primarily on the coupling effects caused by reactor feedback and compares the observations with forced cooled reactors. A number of reactor startup transients have been modeled, and issues such as power peaking, and power-to-flow mismatches, and loading transients were examined, including the possibility of heat flow from the heat exchanger back into the reactor. This system model is envisioned as a tool to be used for screening various heat pipe cooled reactor concepts, for designing and developing test facility requirements, for use in safety evaluations, and for developing test criteria for in-pile and out-of-pile test facilities. .

Altering the cooling rate dependence of phase formation during rapid solidification in the Nd 2Fe 14B system

NASA Astrophysics Data System (ADS)

Branagan, D. J.; McCallum, R. W.

In order to evaluate the effects of additions on the solidification behavior of Nd 2Fe 14B, a stoichiometric alloy was modified with elemental additions of Ti or C and a compound addition of Ti with C. For each alloy, a series of wheel speed runs was undertaken, from which the optimum wheel speeds and optimum energy products were determined. On the BHmax versus wheel speed plots, regions were identified in order to analyze the changes with cooling rates leading to phase formation brought about by the alloy modifications. The compilation of the regional data of the modified alloys showed their effects on altering the cooling rate dependence of phase formation. It was found that the regions of properitectic iron formation, glass formation, and the optimum cooling rate can be changed by more than a factor of two through appropriate alloying additions. The effects of the alloy modifications can be visualized in a convenient fashion through the use of a model continuous cooling transformation (CCT) diagram which represents phase formation during the solidification process under continuous cooling conditions for a wide range of cooling rates from rapid solidification to equilibrium cooling.

Cycle time improvement for plastic injection moulding process by sub groove modification in conformal cooling channel

NASA Astrophysics Data System (ADS)

Kamarudin, K.; Wahab, M. S.; Batcha, M. F. M.; Shayfull, Z.; Raus, A. A.; Ahmed, Aqeel

2017-09-01

Mould designers have been struggling for the improvement of the cooling system performance, despite the fact that the cooling system complexity is physically limited by the fabrication capability of the conventional tooling methods. However, the growth of Solid Free Form Technology (SFF) allow the mould designer to develop more than just a regular conformal cooling channel. Numerous researchers demonstrate that conformal cooling channel was tremendously given significant result in the improvement of productivity and quality in the plastic injection moulding process. This paper presents the research work that applies the passive enhancement method in square shape cooling channel to enhance the efficiency of cooling performance by adding the sub groove to the cooling channel itself. Previous design that uses square shape cooling channel was improved by adding various numbers of sub groove to meet the best sub groove design that able reduced the cooling time. The effect of sub groove design on cooling time was investigated by Autodesk Modlflow Insight software. The simulation results showed that the various sub groove designs give different values to ejection time. The Design 7 showed the lowest value of ejection time with 24.3% increment. The addition of sub groove significantly increased a coolant velocity and a rate of heat transfer from molten plastic to coolant.

Corrosion inhibitors for solar heating and cooling systems

NASA Technical Reports Server (NTRS)

Humphries, T. S.; Deramus, G. E., Jr.

1977-01-01

Problems dealing with corrosion and corrosion protection of solar heating and cooling systems are discussed. A test program was conducted to find suitable and effective corrosion inhibitors for systems employing either water or antifreeze solutions for heat transfer and storage. Aluminum-mild-steel-copper-stainless steel assemblies in electrical contact were used to simulate a multimetallic system which is the type most likely to be employed. Several inhibitors show promise for this application.

Study of using microfiltration and reverse osmosis membrane technologies for reclaiming cooling water in the power industry.

PubMed

Li, J; Xu, Z Y; An, H G; Liu, L Q

2007-07-01

A study of using dual membrane technologies, microfiltration (MF) and reverse osmosis (RO), for reclaiming blowdown of the cooling tower was conducted at ZJK power plant, Hebei province, China. The study shows that the combined MF-RO system can effectively reduce water consumption in the power industry. The results indicate that MF process is capable of producing a filtrate suitable for RO treatment and achieving a silt density index (SDI) less than 2, turbidity of 0.2 NTU. The water quality of RO effluent is very good with an average conductivity of about 40 micros/cm and rejection of 98%. The product water is suitable for injection into the cooling tower to counteract with cooling water intrusion. After adopting this system, water-saving effectiveness as expressed in terms of cycles of concentration could be increased from 2.5-2.8 times to 5 times.

Effects of air velocity on laying hen production from 24 to 27 weeks under simulated evaporatively cooled conditions

USDA-ARS?s Scientific Manuscript database

Thermal conditions play a major role in production efficiency in commercial poultry production. Mitigation of thermal stress can improve productivity, but must be achieved economically. Weather and system design can limit effectiveness of evaporative cooling and increased air movement has been sho...

The Effect of Variable Gravity on the Cooling Performance of a 16-Nozzle Spray Array

DTIC Science & Technology

2008-09-01

Coolants and Capabilities [1]. spray cooling, have been studied in depth and are currently being used on various types of systems. Mudawar [1] presented many...meniscus. Surface modifications could be made to reduce this effect while enhancing overall operability. 58 Bibliography [1] Mudawar , I., “Assessment of

Optimal design variable considerations in the use of phase change materials in indirect evaporative cooling

NASA Astrophysics Data System (ADS)

Chilakapaty, Ankit Paul

The demand for sustainable, energy efficient and cost effective heating and cooling solutions is exponentially increasing with the rapid advancement of computation and information technology. Use of latent heat storage materials also known as phase change materials (PCMs) for load leveling is an innovative solution to the data center cooling demands. These materials are commercially available in the form of microcapsules dispersed in water, referred to as the microencapsulated phase change slurries and have higher heat capacity than water. The composition and physical properties of phase change slurries play significant role in energy efficiency of the cooling systems designed implementing these PCM slurries. Objective of this project is to study the effect of PCM particle size, shape and volumetric concentration on overall heat transfer potential of the cooling systems designed with PCM slurries as the heat transfer fluid (HTF). In this study uniform volume heat source model is developed for the simulation of heat transfer potential using phase change materials in the form of bulk temperature difference in a fully developed flow through a circular duct. Results indicate the heat transfer potential increases with PCM volumetric concentration with gradually diminishing returns. Also, spherical PCM particles offer greater heat transfer potential when compared to cylindrical particles. Results of this project will aid in efficient design of cooling systems based on PCM slurries.

The Influence of Various Parameters on the Success of Sensor-Controlled Scalp Cooling in Preventing Chemotherapy-Induced Alopecia.

PubMed

Schaffrin-Nabe, Dörthe; Schmitz, Inge; Josten-Nabe, Anke; von Hehn, Ulrike; Voigtmann, Rudolf

2015-01-01

The influence of systemic comorbidities on the success of scalp cooling during chemotherapy (CT) is widely unexplored. Comorbidities often require additional medication which itself can occasionally cause alopecia. This study investigates the influence of selected parameters on the efficacy of scalp cooling for the prevention of CT-induced alopecia. 226 cancer patients were treated with various CT regimens in combination with sensor-controlled scalp cooling. 136 breast cancer patients received (neo)adjuvant therapy, and 76 of these patients received epirubicine and cyclophosphamide (4× EC 3w) followed by paclitaxel (12× T w). The following parameters were prospectively investigated: chemotherapy-induced alopecia, systemic comorbidities and co-medication, nicotine abuse, hair treatment, menopausal status, and trichologic status. Scalp cooling was successful (no or not visible hair loss; common toxicity criteria 0-1) in 65% of all patients, in 65% of the 136 breast cancer patients, and in 68% of the 76 patients receiving EC/T. In this subgroup, premenopausal patients (p = 0.009) and those without systemic comorbidities (p = 0.003), without co-medication (p < 0.001) and with high hair density (p = 0.038) showed less hair loss during CT; an effect was also seen for nicotine abuse (p = 0.023). Hair length and hair treatment had no significant influence. Sensor-controlled scalp cooling represents an effective addition to supportive cancer therapy. The success of scalp cooling depends on the applied CT regimen. Parameters like menopausal status, systemic comorbidities, medication, nicotine abuse, and original hair density also influence the outcome of hair loss prevention. © 2015 S. Karger GmbH, Freiburg.

Cryogenic Selective Surface - How Cold Can We Go?

NASA Technical Reports Server (NTRS)

Youngquist, Robert; Nurge, Mark

2015-01-01

Selective surfaces have wavelength dependent emissivitya bsorption. These surfaces can be designed to reflect solar radiation, while maximizing infrared emittance, yielding a cooling effect even in sunlight. On earth cooling to -50 C below ambient has been achieved, but in space, outside of the atmosphere, theory using ideal materials has predicted a maximum cooling to 40 K! If this result holds up for real world materials and conditions, then superconducting systems and cryogenic storage can be achieved in space without active cooling. Such a result would enable long term cryogenic storage in deep space and the use of large scale superconducting systems for such applications as galactic cosmic radiation (GCR) shielding and large scale energy storage.

Experimental study of an air-cooled thermal management system for high capacity lithium-titanate batteries

NASA Astrophysics Data System (ADS)

Giuliano, Michael R.; Prasad, Ajay K.; Advani, Suresh G.

2012-10-01

Lithium-titanate batteries have become an attractive option for battery electric vehicles and hybrid electric vehicles. In order to maintain safe operating temperatures, these batteries must be actively cooled during operation. Liquid-cooled systems typically employed for this purpose are inefficient due to the parasitic power consumed by the on-board chiller unit and the coolant pump. A more efficient option would be to circulate ambient air through the battery bank and directly reject the heat to the ambient. We designed and fabricated such an air-cooled thermal management system employing metal-foam based heat exchanger plates for sufficient heat removal capacity. Experiments were conducted with Altairnano's 50 Ah cells over a range of charge-discharge cycle currents at two air flow rates. It was found that an airflow of 1100 mls-1 per cell restricts the temperature rise of the coolant air to less than 10 °C over ambient even for 200 A charge-discharge cycles. Furthermore, it was shown that the power required to drive the air through the heat exchanger was less than a conventional liquid-cooled thermal management system. The results indicate that air-cooled systems can be an effective and efficient method for the thermal management of automotive battery packs.

Modeling and Simulation of A Microchannel Cooling System for Vitrification of Cells and Tissues.

PubMed

Wang, Y; Zhou, X M; Jiang, C J; Yu, Y T

The microchannel heat exchange system has several advantages and can be used to enhance heat transfer for vitrification. To evaluate the microchannel cooling method and to analyze the effects of key parameters such as channel structure, flow rate and sample size. A computational flow dynamics model is applied to study the two-phase flow in microchannels and its related heat transfer process. The fluid-solid coupling problem is solved with a whole field solution method (i.e., flow profile in channels and temperature distribution in the system being simulated simultaneously). Simulation indicates that a cooling rate >10 4 C/min is easily achievable using the microchannel method with the high flow rate for a board range of sample sizes. Channel size and material used have significant impact on cooling performance. Computational flow dynamics is useful for optimizing the design and operation of the microchannel system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

Energy efficient control of a cooling system cooling an electronic system is provided. The control includes automatically determining at least one adjusted control setting for at least one adjustable cooling component of a cooling system cooling the electronic system. The automatically determining is based, at least in part, on power being consumed by the cooling system and temperature of a heat sink to which heat extracted by the cooling system is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the coolingmore » system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on one or more experimentally obtained models relating the targeted temperature and power consumption of the one or more adjustable cooling components of the cooling system.« less

Cryogenic system for COMET experiment at J-PARC

NASA Astrophysics Data System (ADS)

Ki, Taekyung; Yoshida, Makoto; Yang, Ye; Ogitsu, Toru; Iio, Masami; Makida, Yasuhiro; Okamura, Takahiro; Mihara, Satoshi; Nakamoto, Tatsushi; Sugano, Michinaka; Sasaki, Ken-ichi

2016-07-01

Superconducting conductors and cryogenic refrigeration are key factors in the accelerator science because they enable the production of magnets needed to control and detect the particles under study. In Japan, a system for COMET (Coherent Muon to Electron Transition), which will produce muon beam lines, is under the construction at J-PARC (Japan Proton Accelerator Research Complex). The system consists of three superconducting magnets; the first is a pion-capture solenoid, the second is a muon-transport solenoid, and the third is a detector solenoid. It is necessary to cool down the magnets efficiently using two-phase helium and maintain them securely at 4.5 K. For stable cryogenic refrigeration of the magnets, a suitable cooling method, structures, and the irradiation effect on materials should be investigated. In this paper, we focus on the development of an overall cryogenic system for cooling the capture and transport solenoids. A conduction-cooling method is considered for cooling the capture and transport solenoids because of the advantages such as the reduction of total heat load, fewer components, and simplified structure. To supply cryogenic fluids (4.5 K liquid helium and 58 K gas helium) and currents to the conduction-cooled magnets subjected to high irradiation, cryogenic components (cooling paths in the magnets, transfer tubes, and a current lead box) are developed. Based on the environment of high irradiation, the conditions (temperature and pressure) of helium in cooling paths are estimated, as well as the temperature of the capture magnet. We develop a dynamic model for quench simulation and estimate the maximum pressure in the cooling pipe when the capture magnet quenches. We conclude with a discussion of the next steps and estimated challenges for the cryogenic system.

The Onset of Thermally Unstable Cooling from the Hot Atmospheres of Giant Galaxies in Clusters: Constraints on Feedback Models

NASA Astrophysics Data System (ADS)

Hogan, M. T.; McNamara, B. R.; Pulido, F. A.; Nulsen, P. E. J.; Vantyghem, A. N.; Russell, H. R.; Edge, A. C.; Babyk, Iu.; Main, R. A.; McDonald, M.

2017-12-01

We present accurate mass and thermodynamic profiles for 57 galaxy clusters observed with the Chandra X-ray Observatory. We investigate the effects of local gravitational acceleration in central cluster galaxies, and explore the role of the local free-fall time ({t}{ff}) in thermally unstable cooling. We find that the radially averaged cooling time ({t}{cool}) is as effective an indicator of cold gas, traced through its nebular emission, as the ratio {t}{cool}/{t}{ff}. Therefore, {t}{cool} primarily governs the onset of thermally unstable cooling in hot atmospheres. The location of the minimum {t}{cool}/{t}{ff}, a thermodynamic parameter that many simulations suggest is key in driving thermal instability, is unresolved in most systems. Consequently, selection effects bias the value and reduce the observed range in measured {t}{cool}/{t}{ff} minima. The entropy profiles of cool-core clusters are characterized by broken power laws down to our resolution limit, with no indication of isentropic cores. We show, for the first time, that mass isothermality and the K\\propto {r}2/3 entropy profile slope imply a floor in {t}{cool}/{t}{ff} profiles within central galaxies. No significant departures of {t}{cool}/{t}{ff} below 10 are found. This is inconsistent with models that assume thermally unstable cooling ensues from linear perturbations at or near this threshold. We find that the inner cooling times of cluster atmospheres are resilient to active galactic nucleus (AGN)-driven change, suggesting gentle coupling between radio jets and atmospheric gas. Our analysis is consistent with models in which nonlinear perturbations, perhaps seeded by AGN-driven uplift of partially cooled material, lead to cold gas condensation.

Cryogenetically Cooled Field Effect Transistors for Low-Noise Systems

NASA Technical Reports Server (NTRS)

Wollack, Edward J.; Rabin, Douglas M. (Technical Monitor)

2002-01-01

Recent tends in the design, fabrication and use of High-Electron-Mobility-Transistors (HEMT) in low noise amplifiers are reviewed. Systems employing these devices have achieved the lowest system noise for wavelengths greater than three millimeters with relatively modest cryogenic cooling requirements in a variety of ground and space based applications. System requirements which arise in employing such devices in imaging applications are contrasted with other leading coherent detector candidates at microwave wavelengths. Fundamental and practical limitations which arise in the context of microwave application of field effect devices at cryogenic temperatures will be discussed from a component and systems point of view.

Cryogenically Cooled Field Effect Transistors for Low-Noise Systems

NASA Technical Reports Server (NTRS)

Wollack, Edward J.

2002-01-01

Recent tends in the design, fabrication and use of High-Electron-Mobility-Transistors (HEMT) in low noise amplifiers are reviewed. Systems employing these devices have achieved the lowest system noise for wavelengths greater than three millimeters with relatively modest cryogenic cooling requirements in a variety of ground and space based applications. System requirements which arise in employing such devices in imaging applications are contrasted with other leading coherent detector candidates at microwave wavelengths. Fundamental and practical limitations which arise in the context of microwave application of field effect devices at cryogenic temperatures will be discussed from a component and systems point of view.

Comparison of different cooling regimes within a shortened liquid cooling/warming garment on physiological and psychological comfort during exercise

NASA Technical Reports Server (NTRS)

Leon, Gloria R.; Koscheyev, Victor S.; Coca, Aitor; List, Nathan

2004-01-01

The aim of this study was to compare the effectiveness of different cooling regime intensities to maintain physiological and subjective comfort during physical exertion levels comparable to that engaged in during extravehicular activities (EVA) in space. We studied eight subjects (six males, two females) donned in our newly developed physiologically based shortened liquid cooling/warming garment (SLCWG). Rigorous (condition 1) and mild (condition 2) water temperature cooling regimes were compared at physical exertion levels comparable to that performed during EVA to ascertain the effectiveness of a lesser intensity of cooling in maintaining thermal comfort, thus reducing energy consumption in the portable life support system. Exercise intensity was varied across stages of the session. Finger temperature, rectal temperature, and subjective perception of overall body and hand comfort were assessed. Finger temperature was significantly higher in the rigorous cooling condition and showed a consistent increase across exercise stages, likely due to the restriction of heat extraction because of the intensive cold. In the mild cooling condition, finger temperature exhibited an overall decline with cooling, indicating greater heat extraction from the body. Rectal temperature was not significantly different between conditions, and showed a steady increase over exercise stages in both rigorous and mild cooling conditions. Ratings of overall comfort were 30% higher (more positive) and more stable in mild cooling (p<0.001). The mild cooling regime was more effective than rigorous cooling in allowing the process of heat exchange to occur, thus maintaining thermal homeostasis and subjective comfort during physical exertion.

Liquid over-feeding air conditioning system and method

DOEpatents

Mei, V.C.; Chen, F.C.

1993-09-21

A refrigeration air conditioning system utilizing a liquid over-feeding operation is described. A liquid refrigerant accumulator-heat exchanger is placed in the system to provide a heat exchange relationship between hot liquid refrigerant discharged from condenser and a relatively cool mixture of liquid and vaporous refrigerant discharged from the evaporator. This heat exchange relationship substantially sub-cools the hot liquid refrigerant which undergoes little or no evaporation across the expansion device and provides a liquid over-feeding operation through the evaporator for effectively using 100 percent of evaporator for cooling purposes and for providing the aforementioned mixture of liquid and vaporous refrigerant. 1 figure.

Experimental Investigation of Turbine Vane Heat Transfer for Alternative Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nix, Andrew Carl

The focus of this program was to experimentally investigate advanced gas turbine cooling schemes and the effects of and factors that contribute to surface deposition from particulate matter found in coal syngas exhaust flows on turbine airfoil heat transfer and film cooling, as well as to characterize surface roughness and determine the effects of surface deposition on turbine components. The program was a comprehensive, multi-disciplinary collaborative effort between aero-thermal and materials faculty researchers and the Department of Energy, National Energy Technology Laboratory (NETL). The primary technical objectives of the program were to evaluate the effects of combustion of syngas fuelsmore » on heat transfer to turbine vanes and blades in land-based power generation gas turbine engines. The primary questions to be answered by this investigation were; What are the factors that contribute to particulate deposition on film cooled gas turbine components? An experimental program was performed in a high-temperature and pressure combustion rig at the DOE NETL; What is the effect of coal syngas combustion and surface deposition on turbine airfoil film cooling? Deposition of particulate matter from the combustion gases can block film cooling holes, decreasing the flow of the film coolant and the film cooling effectiveness; How does surface deposition from coal syngas combustion affect turbine surface roughness? Increased surface roughness can increase aerodynamic losses and result in decreased turbine hot section efficiency, increasing engine fuel consumption to maintain desired power output. Convective heat transfer is also greatly affected by the surface roughness of the airfoil surface; Is there any significant effect of surface deposition or erosion on integrity of turbine airfoil thermal barrier coatings (TBC) and do surface deposits react with the TBC in any way to decrease its thermal insulating capability? Spallation and erosion of TBC is a persistent problem in modern turbine engines; and What advancements in film cooling hole geometry and design can increase effectiveness of film cooling in turbines burning high-hydrogen coal syngas due to the higher heat loads and mass flow rates of the core flow? Experimental and numerical investigations of advanced cooling geometries that can improve resistance to surface deposition were performed. The answers to these questions were investigated through experimental measurements of turbine blade surface temperature and coolant coverage (via infrared camera images and thermocouples) and time-varying surface roughness in the NETL high-pressure combustion rig with accelerated, simulated surface deposition and advanced cooling hole concepts, coupled with detailed materials analysis and characterization using conventional methods of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), 3-D Surface Topography (using a 3-D stylus profilometer). Detailed surface temperatures and cooling effectiveness could not be measured due to issues with the NETL infrared camera system. In collaboration with faculty startup funding from the principal investigator, experimental and numerical investigations were performed of an advanced film cooling hole geometry, the anti-vortex hole (AVH), focusing on improving cooling effectiveness and decreasing the counter-rotating vortex of conventional cooling holes which can entrain mainstream particulate matter to the surface. The potential benefit of this program is in gaining a fundamental understanding of how the use of alternative fuels will effect the operation of modern gas turbine engines, providing valuable data for more effective cooling designs for future turbine systems utilizing alternative fuels.« less

Experimental implementation of heat-bath algorithmic cooling using solid-state nuclear magnetic resonance.

PubMed

Baugh, J; Moussa, O; Ryan, C A; Nayak, A; Laflamme, R

2005-11-24

The counter-intuitive properties of quantum mechanics have the potential to revolutionize information processing by enabling the development of efficient algorithms with no known classical counterparts. Harnessing this power requires the development of a set of building blocks, one of which is a method to initialize the set of quantum bits (qubits) to a known state. Additionally, fresh ancillary qubits must be available during the course of computation to achieve fault tolerance. In any physical system used to implement quantum computation, one must therefore be able to selectively and dynamically remove entropy from the part of the system that is to be mapped to qubits. One such method is an 'open-system' cooling protocol in which a subset of qubits can be brought into contact with an external system of large heat capacity. Theoretical efforts have led to an implementation-independent cooling procedure, namely heat-bath algorithmic cooling. These efforts have culminated with the proposal of an optimal algorithm, the partner-pairing algorithm, which was used to compute the physical limits of heat-bath algorithmic cooling. Here we report the experimental realization of multi-step cooling of a quantum system via heat-bath algorithmic cooling. The experiment was carried out using nuclear magnetic resonance of a solid-state ensemble three-qubit system. We demonstrate the repeated repolarization of a particular qubit to an effective spin-bath temperature, and alternating logical operations within the three-qubit subspace to ultimately cool a second qubit below this temperature. Demonstration of the control necessary for these operations represents an important step forward in the manipulation of solid-state nuclear magnetic resonance qubits.

Cooling Effects of Wearer-Controlled Vaporization for Extravehicular Activity.

PubMed

Tanaka, Kunihiko; Nagao, Daiki; Okada, Kosuke; Nakamura, Koji

2017-04-01

The extravehicular activity suit currently used by the United States in space includes a liquid cooling and ventilation garment (LCVG) that controls thermal conditions. Previously, we demonstrated that self-perspiration for evaporative cooling (SPEC) garment effectively lowers skin temperature without raising humidity in the garment. However, the cooling effect is delayed until a sufficient dose of water permeates and evaporates. In the present study, we hypothesized that wearer-controlled vaporization improves the cooling effect. Six healthy subjects rode a cycle ergometer under loads of 30, 60, 90, and 120 W for durations of 3 min each. Skin temperature and humidity on the back were measured continuously. Subjects wore and tested three garments: 1) a spandex garment without any cooling device (Normal); 2) a simulated LCVG (s-LCVG) or spandex garment knitted with a vinyl tube for flowing and permeating water; and 3) a garment that allowed wearer-controlled vaporization (SPEC-W). The use of s-LCVG reduced skin temperature by 1.57 ± 0.14°C during 12 min of cooling. Wearer-controlled vaporization of the SPEC-W effectively and significantly lowered skin temperature from the start to the end of cycle exercise. This decrease was significantly larger than that achieved using s-LCVG. Humidity in the SPEC-W was significantly lower than that in s-LCVG. This preliminary study suggests that SPEC-W is effective in lowering skin temperature without raising humidity in the garment. The authors think it would be useful in improving the design of a cooling system for extravehicular activity.Tanaka K, Nagao D, Okada K, Nakamura K. Cooling effects of wearer-controlled vaporization for extravehicular activity. Aerosp Med Hum Perform. 2017; 88(4):418-422.

Numerical study of a cryogen-free vuilleumier type pulse tube cryocooler operating below 10 K

NASA Astrophysics Data System (ADS)

Wang, Y. N.; Wang, X. T.; Dai, W.; Luo, E. C.

2017-12-01

This paper presents a numerical investigation on a Vuilleumier (VM) type pulse tube cooler. Different from previous systems that use liquid nitrogen, Stirling type pre-coolers are used to provide the cooling power for the thermal compressor, which leads to a convenient cryogen-free system and offers the flexibility of changing working temperature range of the thermal compressor to obtain an optimum efficiency. Firstly, main component dimensions were optimized with lowest no-load temperature as the target. Then the dependence of system performance on average pressure, frequency, displacer displacement amplitude and thermal compressor pre-cooling temperature were studied. Finally, the effect of pre-cooling temperature on overall cooling efficiency at 5 K was studied. A highest relative Carnot efficiency of 0.82 % was predicted with an average pressure of 2.5 MPa, a frequency of 3 Hz, a displacer displacement amplitude of 6.5 mm, ambient end temperature 300 K and pre-cooling temperature 65 K, respectively.

Relationships between molecular structure and kinetic and thermodynamic controls in lipid systems. Part III. Crystallization and phase behavior of 1-palmitoyl-2,3-stearoyl-sn-glycerol (PSS) and tristearoylglycerol (SSS) binary system.

PubMed

Bouzidi, Laziz; Narine, Suresh S

2012-01-01

The phase behavior of 1-palmitoyl-2,3-distearoyl-sn-glycerol (PSS)/tristearoylglycerol (SSS) binary system was investigated in terms of polymorphism, crystallization and melting behavior, microstructure and solid fat content (SFC) using widely different constant cooling rates. Kinetic phase diagrams were experimentally determined from the DSC heating thermograms and analyzed using a thermodynamic model to account for non-ideality of mixing. The kinetic phase diagram presented a typical eutectic behavior with a eutectic point at the 0.5(PSS) mixture with a probable precipitation line from 0.5(PSS) to 1.0(PSS), regardless of the rate at which the sample was cooled. The eutectic temperature decreased only slightly with increasing cooling rate. PSS has a strong effect on the physical properties of the PSS-SSS mixtures. In fact, the overall phase behavior of the PSS-SSS binary system was determined, for a very large part, by the asymmetrical TAG. Moreover, PSS is a key driver of the high stability observed in crystal growth, polymorphism and phase development. Levels as low as 10% PSS, when cooled slowly, and 30% when cooled rapidly, were found to be sufficient to suppress the effect of thermal processing. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Novel desiccant cooling system using indirect evaporative cooler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belding, W.A.; Delmas, M.P.F.

1997-12-31

An effective desiccant cooling system must efficiently reject adsorption and carryover heat from the process airstream. Rotary heat exchangers are typically used to remove this heat in currently available desiccant equipment, but these devices can leak humid air from the regeneration side of the process into the dry process side, degrading performance. Using a different approach, high cooling capacities and coefficients of performance (COPs) have been achieved in a desiccant cooling system without a heat wheel or bulky stationary heat exchanger. Using a desiccant wheel in conjunction with a compact indirect evaporative cooler and a small air-to-air heat exchanger, amore » cooling system has been developed that eliminates the need for deep dehumidification by the desiccant wheel and at the same time provides 25% to 35% ventilation air to the conditioned space. Using a 0.68 m (27 in.) diameter by 0.2 m (8 in.) deep type 1 M desiccant wheel regenerated at 175 C (347 F), 15.0 kW (4.3 tons) of cooling were achieved with a thermal COP of 0.72. With the addition of a direct evaporative cooler, humidity control over a broad range can be offered by the system. The low desiccant wheel volume and the compact nature of the indirect evaporative coolers result in equipment with a low potential first cost, assuming economies of scale. Equipment presently under development is expected to exceed a gross cooling COP of 0.9.« less

Compressor bleed cooling fluid feed system

DOEpatents

Donahoo, Eric E; Ross, Christopher W

2014-11-25

A compressor bleed cooling fluid feed system for a turbine engine for directing cooling fluids from a compressor to a turbine airfoil cooling system to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The compressor bleed cooling fluid feed system may enable cooling fluids to be exhausted from a compressor exhaust plenum through a downstream compressor bleed collection chamber and into the turbine airfoil cooling system. As such, the suction created in the compressor exhaust plenum mitigates boundary layer growth along the inner surface while providing flow of cooling fluids to the turbine airfoils.

Effects of system size and cooling rate on the structure and properties of sodium borosilicate glasses from molecular dynamics simulations.

PubMed

Deng, Lu; Du, Jincheng

2018-01-14

Borosilicate glasses form an important glass forming system in both glass science and technologies. The structure and property changes of borosilicate glasses as a function of thermal history in terms of cooling rate during glass formation and simulation system sizes used in classical molecular dynamics (MD) simulation were investigated with recently developed composition dependent partial charge potentials. Short and medium range structural features such as boron coordination, Si and B Q n distributions, and ring size distributions were analyzed to elucidate the effects of cooling rate and simulation system size on these structure features and selected glass properties such as glass transition temperature, vibration density of states, and mechanical properties. Neutron structure factors, neutron broadened pair distribution functions, and vibrational density of states were calculated and compared with results from experiments as well as ab initio calculations to validate the structure models. The results clearly indicate that both cooling rate and system size play an important role on the structures of these glasses, mainly by affecting the 3 B and 4 B distributions and consequently properties of the glasses. It was also found that different structure features and properties converge at different sizes or cooling rates; thus convergence tests are needed in simulations of the borosilicate glasses depending on the targeted properties. The results also shed light on the complex thermal history dependence on structure and properties in borosilicate glasses and the protocols in MD simulations of these and other glass materials.

Effects of system size and cooling rate on the structure and properties of sodium borosilicate glasses from molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Deng, Lu; Du, Jincheng

2018-01-01

Borosilicate glasses form an important glass forming system in both glass science and technologies. The structure and property changes of borosilicate glasses as a function of thermal history in terms of cooling rate during glass formation and simulation system sizes used in classical molecular dynamics (MD) simulation were investigated with recently developed composition dependent partial charge potentials. Short and medium range structural features such as boron coordination, Si and B Qn distributions, and ring size distributions were analyzed to elucidate the effects of cooling rate and simulation system size on these structure features and selected glass properties such as glass transition temperature, vibration density of states, and mechanical properties. Neutron structure factors, neutron broadened pair distribution functions, and vibrational density of states were calculated and compared with results from experiments as well as ab initio calculations to validate the structure models. The results clearly indicate that both cooling rate and system size play an important role on the structures of these glasses, mainly by affecting the 3B and 4B distributions and consequently properties of the glasses. It was also found that different structure features and properties converge at different sizes or cooling rates; thus convergence tests are needed in simulations of the borosilicate glasses depending on the targeted properties. The results also shed light on the complex thermal history dependence on structure and properties in borosilicate glasses and the protocols in MD simulations of these and other glass materials.

Effect of makeup water properties on the condenser fouling in power planr cooling system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Safari, I.; Walker, M.; Abbasian, J.

2011-01-01

The thermoelectric power industry in the U.S. uses a large amount of fresh water. As available freshwater for use in thermoelectric power production becomes increasingly limited, use of nontraditional water sources is of growing interest. Utilization of nontraditional water, in cooling systems increases the potential for mineral precipitation on heat exchanger surfaces. In that regard, predicting the accelerated rate of scaling and fouling in condenser is crucial to evaluate the condenser performance. To achieve this goal, water chemistry should be incorporated in cooling system modeling and simulation. This paper addresses the effects of various makeup water properties on the coolingmore » system, namely pH and aqueous speciation, both of which are important factors affecting the fouling rate in the main condenser. Detailed modeling of the volatile species desorption (i.e. CO{sub 2} and NH{sub 3}), the formation of scale in the recirculating system, and the relationship between water quality and the corresponding fouling rates is presented.« less

AUTOMOTIVE DIESEL MAINTENACE 1. UNIT XV, I--MAINTAINING THE COOLING SYSTEM, CUMMINS DIESEL ENGINE, I--UNIT INSTALLATION--TRANSMISSION.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE FUNCTION AND MAINTENANCE OF THE DIESEL ENGINE COOLING SYSTEM AND THE PROCEDURES FOR TRANSMISSION INSTALLATION. TOPICS ARE (1) IMPORTANCE OF THE COOLING SYSTEM, (2) COOLING SYSTEM COMPONENTS, (3) EVALUATING COOLING SYSTEM FAILURES, (4) CARING FOR THE COOLING SYSTEM,…

Thermodynamic transport properties of nitrogen tetroxide in hypercritical conditions for regenerative cooling of a rocket engine. Volume 1: Tests

NASA Astrophysics Data System (ADS)

Saccoccia, Giorgio

The thermodynamical and transport properties are studied for nitrogen tetroxide (N2O4), which is utilized in hypercritical conditions as oxidants and cooling fluids in rocket propulsion with regenerative cooling systems. An equation of state was performed in the varied zone of the state diagram, taking into account the phase change and two dissociation reactions. The study of the transport properties and state effects is based on the results of the fluid molecular theory. In addition to the state effects, the simple application results obtained for a case of thermal exchange in a cooling channel was studied through the behavior of the substance.

Co nanoparticles inserted into a porous carbon amorphous matrix: the role of cooling field and temperature on the exchange bias effect.

PubMed

Fernández-García, María Paz; Gorria, Pedro; Sevilla, Marta; Fuertes, Antonio B; Boada, Roberto; Chaboy, Jesús; Aquilanti, Giuliana; Blanco, Jesús A

2011-01-21

We report unusual cooling field dependence of the exchange bias in oxide-coated cobalt nanoparticles embedded within the nanopores of a carbon matrix. The size-distribution of the nanoparticles and the exchange bias coupling observed up to about 200 K between the Co-oxide shell (∼3-4 nm) and the ferromagnetic Co-cores (∼4-6 nm) are the key to understand the magnetic properties of this system. The estimated values of the effective anisotropy constant and saturation magnetization obtained from the fit of the zero-field cooling and field cooling magnetization vs. temperature curves agree quite well with those of the bulk fcc-Co.

Evaporative cooling system for storage of fruits and vegetables - a review.

PubMed

Lal Basediya, Amrat; Samuel, D V K; Beera, Vimala

2013-06-01

Horticultural produce are stored at lower temperature because of their highly perishable nature. There are many methods to cool the environment. Hence, preserving these types of foods in their fresh form demands that the chemical, bio-chemical and physiological changes are restricted to a minimum by close control of space temperature and humidity. The high cost involved in developing cold storage or controlled atmosphere storage is a pressing problem in several developing countries. Evaporative cooling is a well-known system to be an efficient and economical means for reducing the temperature and increasing the relative humidity in an enclosure and this effect has been extensively tried for increasing the shelf life of horticultural produce in some tropical and subtropical countries. In this review paper, basic concept and principle, methods of evaporative cooling and their application for the preservation of fruits and vegetables and economy are also reported. Thus, the evaporative cooler has prospect for use for short term preservation of vegetables and fruits soon after harvest. Zero energy cooling system could be used effectively for short-duration storage of fruits and vegetables even in hilly region. It not only reduces the storage temperature but also increases the relative humidity of the storage which is essential for maintaining the freshness of the commodities.

Effects of cooling system parameters on heat transfer in PAFC stack. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali A.

1985-01-01

Analytical and experimental study for the effects of cooling system parameters on the heat transfer and temperature distribution in the electrode plates of a phosphoric acid fuel-cell has been conducted. An experimental set-up that simulates the operating conditions prevailing in a phosphoric-acid fuel-cell stack was designed and constructed. The set-up was then used to measure the overall heat transfer coefficient, the thermal contact resistance, and the electrode temperature distribution for two different cooling plate configurations. Two types of cooling plate configurations, serpentine and straight, were tested. Air, water, and oil were used as coolants. Measurements for the heat transfer coefficient and the thermal contact resistance were made for various flow rates ranging from 16 to 88 Kg/hr, and stack clamping pressure ranging from O to 3448 Kpa. The experimental results for the overall heat transfer coefficient were utilized to derive mathematical relations for the overall heat transfer coefficient as a function of stack clamping pressure and Reynolds number for the three coolants. The empirically derived formulas were incorporated in a previously developed computer program to predict electrodes temperature distribution and the performance of the stack cooling system. The results obtained were then compared with those available in the literature. The comparison showed maximum deviation of +/- 11%.

Effects of an evaporative cooling system on plasma cortisol, IGF-I, and milk production in dairy cows in a tropical environment

NASA Astrophysics Data System (ADS)

Titto, Cristiane Gonçalves; Negrão, João Alberto; Titto, Evaldo Antonio Lencioni; Canaes, Taissa de Souza; Titto, Rafael Martins; Pereira, Alfredo Manuel Franco

2013-03-01

Access to an evaporative cooling system can increase production in dairy cows because of improved thermal comfort. This study aimed to evaluate the impact of ambient temperature on thermoregulation, plasma cortisol, insulin-like growth factor 1 (IGF-I), and productive status, and to determine the efficiency of an evaporative cooling system on physiological responses under different weather patterns. A total of 28 Holstein cows were divided into two groups, one with and the other without access to a cooling system with fans and mist in the free stall. The parameters were analyzed during morning (0700 hours) and afternoon milking (1430 hours) under five different weather patterns throughout the year (fall, winter, spring, dry summer, and rainy summer). Rectal temperature (RT), body surface temperature (BS), base of tail temperature (TT), and respiratory frequency (RF) were lower in the morning ( P < 0.01). The cooling system did not affect RT, and both the groups had values below 38.56 over the year ( P = 0.11). Cortisol and IGF-I may have been influenced by the seasons, in opposite ways. Cortisol concentrations were higher in winter ( P < 0.05) and IGF-I was higher during spring-summer ( P < 0.05). The air temperature and the temperature humidity index showed positive moderate correlations to RT, BS, TT, and RF ( P < 0.001). The ambient temperature was found to have a positive correlation with the physiological variables, independent of the cooling system, but cooled animals exhibited higher milk production during spring and summer ( P < 0.01).

Effects of an evaporative cooling system on plasma cortisol, IGF-I, and milk production in dairy cows in a tropical environment.

PubMed

Titto, Cristiane Gonçalves; Negrão, João Alberto; Titto, Evaldo Antonio Lencioni; Canaes, Taissa de Souza; Titto, Rafael Martins; Pereira, Alfredo Manuel Franco

2013-03-01

Access to an evaporative cooling system can increase production in dairy cows because of improved thermal comfort. This study aimed to evaluate the impact of ambient temperature on thermoregulation, plasma cortisol, insulin-like growth factor 1 (IGF-I), and productive status, and to determine the efficiency of an evaporative cooling system on physiological responses under different weather patterns. A total of 28 Holstein cows were divided into two groups, one with and the other without access to a cooling system with fans and mist in the free stall. The parameters were analyzed during morning (0700 hours) and afternoon milking (1430 hours) under five different weather patterns throughout the year (fall, winter, spring, dry summer, and rainy summer). Rectal temperature (RT), body surface temperature (BS), base of tail temperature (TT), and respiratory frequency (RF) were lower in the morning (P < 0.01). The cooling system did not affect RT, and both the groups had values below 38.56 over the year (P = 0.11). Cortisol and IGF-I may have been influenced by the seasons, in opposite ways. Cortisol concentrations were higher in winter (P < 0.05) and IGF-I was higher during spring-summer (P < 0.05). The air temperature and the temperature humidity index showed positive moderate correlations to RT, BS, TT, and RF (P < 0.001). The ambient temperature was found to have a positive correlation with the physiological variables, independent of the cooling system, but cooled animals exhibited higher milk production during spring and summer (P < 0.01).

Split radiator design for heat rejection optimization for a waste heat recovery system

DOEpatents

Ernst, Timothy C.; Nelson, Christopher R.

2016-10-18

A cooling system provides improved heat recovery by providing a split core radiator for both engine cooling and condenser cooling for a Rankine cycle (RC). The cooling system includes a radiator having a first cooling core portion and a second cooling core portion. An engine cooling loop is fluidly connected the second cooling core portion. A condenser of an RC has a cooling loop fluidly connected to the first cooling core portion. A valve is provided between the engine cooling loop and the condenser cooling loop adjustably control the flow of coolant in the condenser cooling loop into the engine cooling loop. The cooling system includes a controller communicatively coupled to the valve and adapted to determine a load requirement for the internal combustion engine and adjust the valve in accordance with the engine load requirement.

Modeling a Transient Pressurization with Active Cooling Sizing Tool

NASA Technical Reports Server (NTRS)

Guzik, Monica C.; Plachta, David W.; Elchert, Justin P.

2011-01-01

As interest in the area of in-space zero boil-off cryogenic propellant storage develops, the need to visualize and quantify cryogen behavior during ventless tank self-pressurization and subsequent cool-down with active thermal control has become apparent. During the course of a mission, such as the launch ascent phase, there are periods that power to the active cooling system will be unavailable. In addition, because it is not feasible to install vacuum jackets on large propellant tanks, as is typically done for in-space cryogenic applications for science payloads, instances like the launch ascent heating phase are important to study. Numerous efforts have been made to characterize cryogenic tank pressurization during ventless cryogen storage without active cooling, but few tools exist to model this behavior in a user-friendly environment for general use, and none exist that quantify the marginal active cooling system size needed for power down periods to manage tank pressure response once active cooling is resumed. This paper describes the Transient pressurization with Active Cooling Tool (TACT), which is based on a ventless three-lump homogeneous thermodynamic self-pressurization model1 coupled with an active cooling system estimator. TACT has been designed to estimate the pressurization of a heated but unvented cryogenic tank, assuming an unavailable power period followed by a given cryocooler heat removal rate. By receiving input data on the tank material and geometry, propellant initial conditions, and passive and transient heating rates, a pressurization and recovery profile can be found, which establishes the time needed to return to a designated pressure. This provides the ability to understand the effect that launch ascent and unpowered mission segments have on the size of an active cooling system. A sample of the trends found show that an active cooling system sized for twice the steady state heating rate would results in a reasonable time for tank pressure recovery with ZBO of a liquid oxygen propellant tank.

Energy and environmental evaluation of combined cooling heating and power system

NASA Astrophysics Data System (ADS)

Bugaj, Andrzej

2017-11-01

The paper addresses issues involving problems of implementing combined cooling, heating and power (CCHP) system to industrial facility with well-defined demand profiles of cooling, heating and electricity. The application of CCHP system in this particular industrial facility is being evaluated by comparison with the reference system that consists of three conventional methods of energy supply: (a) electricity from external grid, (b) heat from gas-fired boilers and (c) cooling from vapour compression chillers run by electricity from the grid. The CCHP system scenario is based on the combined heat and power (CHP) plant with gas turbine-compressor arrangement and water/lithium bromide absorption chiller of a single-effect type. Those two scenarios are analysed in terms of annual primary energy usage as well as emissions of CO2. The results of the analysis show an extent of primary energy savings of the CCHP system in comparison with the reference system. Furthermore, the environmental impact of the CCHP usage, in the form of greenhouse gases emission reductions, compares quite favourably with the reference conventional option.

Active (air-cooled) vs. passive (phase change material) thermal management of high power lithium-ion packs: Limitation of temperature rise and uniformity of temperature distribution

NASA Astrophysics Data System (ADS)

Sabbah, Rami; Kizilel, R.; Selman, J. R.; Al-Hallaj, S.

The effectiveness of passive cooling by phase change materials (PCM) is compared with that of active (forced air) cooling. Numerical simulations were performed at different discharge rates, operating temperatures and ambient temperatures of a compact Li-ion battery pack suitable for plug-in hybrid electric vehicle (PHEV) propulsion. The results were also compared with experimental results. The PCM cooling mode uses a micro-composite graphite-PCM matrix surrounding the array of cells, while the active cooling mode uses air blown through the gaps between the cells in the same array. The results show that at stressful conditions, i.e. at high discharge rates and at high operating or ambient temperatures (for example 40-45 °C), air-cooling is not a proper thermal management system to keep the temperature of the cell in the desirable operating range without expending significant fan power. On the other hand, the passive cooling system is able to meet the operating range requirements under these same stressful conditions without the need for additional fan power.

Controlled cooling of an electronic system based on projected conditions

DOEpatents

David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

2016-05-17

Energy efficient control of a cooling system cooling an electronic system is provided based, in part, on projected conditions. The control includes automatically determining an adjusted control setting(s) for an adjustable cooling component(s) of the cooling system. The automatically determining is based, at least in part, on projected power consumed by the electronic system at a future time and projected temperature at the future time of a heat sink to which heat extracted is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the cooling system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on an experimentally obtained model(s) relating the targeted temperature and power consumption of the adjustable cooling component(s) of the cooling system.

Controlled cooling of an electronic system based on projected conditions

DOEpatents

David, Milnes P.; Iyengar, Madhusudan K.; Schmidt, Roger R.

2015-08-18

Energy efficient control of a cooling system cooling an electronic system is provided based, in part, on projected conditions. The control includes automatically determining an adjusted control setting(s) for an adjustable cooling component(s) of the cooling system. The automatically determining is based, at least in part, on projected power consumed by the electronic system at a future time and projected temperature at the future time of a heat sink to which heat extracted is rejected. The automatically determining operates to reduce power consumption of the cooling system and/or the electronic system while ensuring that at least one targeted temperature associated with the cooling system or the electronic system is within a desired range. The automatically determining may be based, at least in part, on an experimentally obtained model(s) relating the targeted temperature and power consumption of the adjustable cooling component(s) of the cooling system.

Passive cooling system for top entry liquid metal cooled nuclear reactors

DOEpatents

Boardman, Charles E.; Hunsbedt, Anstein; Hui, Marvin M.

1992-01-01

A liquid metal cooled nuclear fission reactor plant having a top entry loop joined satellite assembly with a passive auxiliary safety cooling system for removing residual heat resulting from fuel decay during shutdown, or heat produced during a mishap. This satellite type reactor plant is enhanced by a backup or secondary passive safety cooling system which augments the primary passive auxiliary cooling system when in operation, and replaces the primary cooling system when rendered inoperative.

Electron cooling of a bunched ion beam in a storage ring

NASA Astrophysics Data System (ADS)

Zhao, He; Mao, Lijun; Yang, Jiancheng; Xia, Jiawen; Yang, Xiaodong; Li, Jie; Tang, Meitang; Shen, Guodong; Ma, Xiaoming; Wu, Bo; Wang, Geng; Ruan, Shuang; Wang, Kedong; Dong, Ziqiang

2018-02-01

A combination of electron cooling and rf system is an effective method to compress the beam bunch length in storage rings. A simulation code based on multiparticle tracking was developed to calculate the bunched ion beam cooling process, in which the electron cooling, intrabeam scattering (IBS), ion beam space-charge field, transverse and synchrotron motion are considered. Meanwhile, bunched ion beam cooling experiments have been carried out in the main cooling storage ring (CSRm) of the Heavy Ion Research Facility in Lanzhou, to investigate the minimum bunch length obtained by the cooling method, and study the dependence of the minimum bunch length on beam and machine parameters. The experiments show comparable results to those from simulation. Based on these simulations and experiments, we established an analytical model to describe the limitation of the bunch length of the cooled ion beam. It is observed that the IBS effect is dominant for low intensity beams, and the space-charge effect is much more important for high intensity beams. Moreover, the particles will not be bunched for much higher intensity beam. The experimental results in CSRm show a good agreement with the analytical model in the IBS dominated regime. The simulation work offers us comparable results to those from the analytical model both in IBS dominated and space-charge dominated regimes.

Design concepts for the ASTROMAG cryogenic system

NASA Technical Reports Server (NTRS)

Green, M. A.; Castles, S.

1987-01-01

Described is a proposed cryogenic system used to cool the superconducting magnet for the Space Station based ASTROMAG Particle Astrophysics Facility. This 2-meter diameter superconducting magnet will be cooled using stored helium II. The paper presents a liquid helium storage concept which would permit cryogenic lifetimes of up to 3 years between refills. It is proposed that the superconducting coil be cooled using superfluid helium pumped by the thermomechanical effect. It is also proposed that the storage tank be resupplied with helium in orbit. A method for charging and discharging the magnet with minimum helium loss using split gas-cooled leads is discussed. A proposal to use a Stirling cycle cryocooler to extend the storage life of the cryostat will also be presented.

Numerical study of the thermo-flow performances of novel finned tubes for air-cooled condensers in power plant

NASA Astrophysics Data System (ADS)

Guo, Yonghong; Du, Xiaoze; Yang, Lijun

2018-02-01

Air-cooled condenser is the main equipment of the direct dry cooling system in a power plant, which rejects heat of the exhaust steam with the finned tube bundles. Therefore, the thermo-flow performances of the finned tubes have an important effect on the optimal operation of the direct dry cooling system. In this paper, the flow and heat transfer characteristics of the single row finned tubes with the conventional flat fins and novel jagged fins are investigated by numerical method. The flow and temperature fields of cooling air for the finned tubes are obtained. Moreover, the variations of the flow resistance and average convection heat transfer coefficient under different frontal velocity of air and jag number are presented. Finally, the correlating equations of the friction factor and Nusselt number versus the Reynolds number are fitted. The results show that with increasing the frontal velocity of air, the heat transfer performances of the finned tubes are enhanced but the pressure drop will increase accordingly, resulting in the average convection heat transfer coefficient and friction factor increasing. Meanwhile, with increasing the number of fin jag, the heat transfer performance is intensified. The present studies provide a reference in optimal designing for the air-cooled condenser of direct air cooling system.

Cryopreservation: Vitrification and Controlled Rate Cooling.

PubMed

Hunt, Charles J

2017-01-01

Cryopreservation is the application of low temperatures to preserve the structural and functional integrity of cells and tissues. Conventional cooling protocols allow ice to form and solute concentrations to rise during the cryopreservation process. The damage caused by the rise in solute concentration can be mitigated by the use of compounds known as cryoprotectants. Such compounds protect cells from the consequences of slow cooling injury, allowing them to be cooled at cooling rates which avoid the lethal effects of intracellular ice. An alternative to conventional cooling is vitrification. Vitrification methods incorporate cryoprotectants at sufficiently high concentrations to prevent ice crystallization so that the system forms an amorphous glass thus avoiding the damaging effects caused by conventional slow cooling. However, vitrification too can impose damaging consequences on cells as the cryoprotectant concentrations required to vitrify cells at lower cooling rates are potentially, and often, harmful. While these concentrations can be lowered to nontoxic levels, if the cells are ultra-rapidly cooled, the resulting metastable system can lead to damage through devitrification and growth of ice during subsequent storage and rewarming if not appropriately handled.The commercial and clinical application of stem cells requires robust and reproducible cryopreservation protocols and appropriate long-term, low-temperature storage conditions to provide reliable master and working cell banks. Though current Good Manufacturing Practice (cGMP) compliant methods for the derivation and banking of clinical grade pluripotent stem cells exist and stem cell lines suitable for clinical applications are available, current cryopreservation protocols, whether for vitrification or conventional slow freezing, remain suboptimal. Apart from the resultant loss of valuable product that suboptimal cryopreservation engenders, there is a danger that such processes will impose a selective pressure on the cells selecting out a nonrepresentative, freeze-resistant subpopulation. Optimizing this process requires knowledge of the fundamental processes that occur during the freezing of cellular systems, the mechanisms of damage and methods for avoiding them. This chapter draws together the knowledge of cryopreservation gained in other systems with the current state-of-the-art for embryonic and induced pluripotent stem cell preservation in an attempt to provide the background for future attempts to optimize cryopreservation protocols.

Influence of Chlorination and Choice of Materials on Fouling in Cooling Water System under Brackish Seawater Conditions

PubMed Central

Rajala, Pauliina; Bomberg, Malin; Huttunen-Saarivirta, Elina; Priha, Outi; Tausa, Mikko; Carpén, Leena

2016-01-01

Cooling systems remove heat from components and industrial equipment. Water cooling, employing natural waters, is typically used for cooling large industrial facilities, such as power plants, factories or refineries. Due to moderate temperatures, cooling water cycles are susceptible to biofouling, inorganic fouling and scaling, which may reduce heat transfer and enhance corrosion. Hypochlorite treatment or antifouling coatings are used to prevent biological fouling in these systems. In this research, we examine biofouling and materials’ degradation in a brackish seawater environment using a range of test materials, both uncoated and coated. The fouling and corrosion resistance of titanium alloy (Ti-6Al-4V), super austenitic stainless steel (254SMO) and epoxy-coated carbon steel (Intershield Inerta160) were studied in the absence and presence of hypochlorite. Our results demonstrate that biological fouling is intensive in cooling systems using brackish seawater in sub-arctic areas. The microfouling comprised a vast diversity of bacteria, archaea, fungi, algae and protozoa. Chlorination was effective against biological fouling: up to a 10–1000-fold decrease in bacterial and archaeal numbers was detected. Chlorination also changed the diversity of the biofilm-forming community. Nevertheless, our results also suggest that chlorination enhances cracking of the epoxy coating. PMID:28773597

Influence of Chlorination and Choice of Materials on Fouling in Cooling Water System under Brackish Seawater Conditions.

PubMed

Rajala, Pauliina; Bomberg, Malin; Huttunen-Saarivirta, Elina; Priha, Outi; Tausa, Mikko; Carpén, Leena

2016-06-15

Cooling systems remove heat from components and industrial equipment. Water cooling, employing natural waters, is typically used for cooling large industrial facilities, such as power plants, factories or refineries. Due to moderate temperatures, cooling water cycles are susceptible to biofouling, inorganic fouling and scaling, which may reduce heat transfer and enhance corrosion. Hypochlorite treatment or antifouling coatings are used to prevent biological fouling in these systems. In this research, we examine biofouling and materials' degradation in a brackish seawater environment using a range of test materials, both uncoated and coated. The fouling and corrosion resistance of titanium alloy (Ti-6Al-4V), super austenitic stainless steel (254SMO) and epoxy-coated carbon steel (Intershield Inerta160) were studied in the absence and presence of hypochlorite. Our results demonstrate that biological fouling is intensive in cooling systems using brackish seawater in sub-arctic areas. The microfouling comprised a vast diversity of bacteria, archaea, fungi, algae and protozoa. Chlorination was effective against biological fouling: up to a 10-1000-fold decrease in bacterial and archaeal numbers was detected. Chlorination also changed the diversity of the biofilm-forming community. Nevertheless, our results also suggest that chlorination enhances cracking of the epoxy coating.

Experimental Study on Active Cooling Systems Used for Thermal Management of High-Power Multichip Light-Emitting Diodes

PubMed Central

2014-01-01

The objective of this study was to develop suitable cooling systems for high-power multichip LEDs. To this end, three different active cooling systems were investigated to control the heat generated by the powering of high-power multichip LEDs in two different configurations (30 and 2 × 15 W). The following cooling systems were used in the study: an integrated multi-fin heat sink design with a fan, a cooling system with a thermoelectric cooler (TEC), and a heat pipe cooling device. According to the results, all three systems were observed to be sufficient for cooling high-power LEDs. Furthermore, it was observed that the integrated multifin heat sink design with a fan was the most efficient cooling system for a 30 W high-power multichip LED. The cooling system with a TEC and 46 W input power was the most efficient cooling system for 2 × 15 W high-power multichip LEDs. PMID:25162058

Performance assessment of a photonic radiative cooling system for office buildings

DOE PAGES

Wang, Weimin; Fernandez, Nick; Katipamula, Srinivas; ...

2017-11-08

Recent advances in materials have demonstrated the ability to maintain radiator surfaces at below-ambient temperatures in the presence of intense, direct sunlight. Daytime radiative cooling is promising for building applications. Here, this paper estimates the energy savings from daytime radiative cooling, specifically based on photonic materials. A photonic radiative cooling system was proposed and modeled using the whole energy simulation program EnergyPlus. A typical medium-sized office building was used for the simulation analysis. Several reference systems were established to quantify the potential of energy savings from the photonic radiative cooling system. The reference systems include a variable-air-volume (VAV) system, amore » hydronic radiant system, and a nighttime radiative cooling system. The savings analysis was made for a number of locations with different climates. Simulation results showed that the photonic radiative cooling system saved between 45% and 68% cooling electricity relative to the VAV system and between 9% and 23% relative to the nighttime radiative cooling system featured with the best coating commercially available on market. Finally, a simple economic analysis was also made to estimate the maximum acceptable incremental cost for upgrading from nighttime cooling to photonic radiative cooling.« less

Performance assessment of a photonic radiative cooling system for office buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Weimin; Fernandez, Nick; Katipamula, Srinivas

Recent advances in materials have demonstrated the ability to maintain radiator surfaces at below-ambient temperatures in the presence of intense, direct sunlight. Daytime radiative cooling is promising for building applications. Here, this paper estimates the energy savings from daytime radiative cooling, specifically based on photonic materials. A photonic radiative cooling system was proposed and modeled using the whole energy simulation program EnergyPlus. A typical medium-sized office building was used for the simulation analysis. Several reference systems were established to quantify the potential of energy savings from the photonic radiative cooling system. The reference systems include a variable-air-volume (VAV) system, amore » hydronic radiant system, and a nighttime radiative cooling system. The savings analysis was made for a number of locations with different climates. Simulation results showed that the photonic radiative cooling system saved between 45% and 68% cooling electricity relative to the VAV system and between 9% and 23% relative to the nighttime radiative cooling system featured with the best coating commercially available on market. Finally, a simple economic analysis was also made to estimate the maximum acceptable incremental cost for upgrading from nighttime cooling to photonic radiative cooling.« less

Development of ZL400 Mine Cooling Unit Using Semi-Hermetic Screw Compressor and Its Application on Local Air Conditioning in Underground Long-Wall Face

NASA Astrophysics Data System (ADS)

Chu, Zhaoxiang; Ji, Jianhu; Zhang, Xijun; Yan, Hongyuan; Dong, Haomin; Liu, Junjie

2016-12-01

Aiming at heat injuries occurring in the process of deep coal mining in China, a ZL400 mine-cooling unit employing semi-hermetic screw compressor with a cooling capacity of 400 kW is developed. This paper introduced its operating principle, structural characteristics and technical indexes. By using the self-built testing platform, some parameters for indication of its operation conditions were tested on the ground. The results show that the aforementioned cooling unit is stable in operation: cooling capacity of the unit was 420 kW underground-test conditions, while its COP (coefficient of performance) reached 3.4. To address the issue of heat injuries existing in No. 16305 U-shaped long-wall ventilation face of Jining No. 3 coal mine, a local air conditioning system was developed with ZL400 cooling unit as the system's core. The paper presented an analysis of characteristics of the air current flowing in the air-mixing and cooling mode of ZL400 cooling unit used in air intake way. Through i-d patterns we described the process of the airflow treatment, such as cooling, mixing and heating, etc. The cooling system decreased dry bulb temperature on working face by 3°C on average and 3.8°C at most, while lowered the web bulb temperature by 3.6°C on average and 4.8°C at most. At the same time, it reduced relative humidity by 5% on average and 8.6% at most. The field application of the ZL400 cooling unit had gain certain effects in air conditioning and provided support for the solution of mine heat injuries in China in terms of technology and equipment.

A simplified analytical solution for thermal response of a one-dimensional, steady state transpiration cooling system in radiative and convective environment

NASA Technical Reports Server (NTRS)

Kubota, H.

1976-01-01

A simplified analytical method for calculation of thermal response within a transpiration-cooled porous heat shield material in an intense radiative-convective heating environment is presented. The essential assumptions of the radiative and convective transfer processes in the heat shield matrix are the two-temperature approximation and the specified radiative-convective heatings of the front surface. Sample calculations for porous silica with CO2 injection are presented for some typical parameters of mass injection rate, porosity, and material thickness. The effect of these parameters on the cooling system is discussed.

Heat-pump-centered integrated community energy systems: System development summary

NASA Astrophysics Data System (ADS)

Calm, J. M.

1980-02-01

An introduction to district heating systems employing heat pumps to enable use of low temperature energy sources is presented. These systems operate as thermal utilities to provide space heating and may also supply space cooling, service water heating, and other thermal services. Otherwise wasted heat from industrial and commercial processes, natural sources including solar and geothermal heat, and heat stored on an annual cycle from summer cooling may be effectively utilized by the systems described. More than one quarter of the energy consumed in the United States is used to heat and cool buildings and to heat service water. Natural gas and oil provide approximately 83% of this energy. The systems described show potential to reduce net energy consumption for these services by 20 to 50% and to allow fuel substitution with less scarce resources not practical in smaller, individual building systems. Seven studies performed for the system development phase are summarized.

Emergency and microfog lubrication and cooling of bearings for Army helicopters

NASA Technical Reports Server (NTRS)

Rosenlieb, J. W.

1978-01-01

An analysis and system study was performed to provide design information regarding lubricant and coolant flow rates and flow paths for effective utilization of the lubricant and coolant in a once-through oil-mist (microfog) and coolant air system. A system was designed, manufactured, coupled with an existing rig and evaluation tests were performed using 46 mm bore split-inner angular-contact ball bearings under 1779N (400 lb.) thrust load. An emergency lubrication aspirator system was also manufactured and tested under lost lubricant conditions. The testing demonstrated the feasibility of using a mist oil and cooling air system to lubricate and cool a high speed helicopter engine mainshaft bearing. The testing also demonstrated the feasibility of using an emergency aspirator lubrication system as a viable survivability concept for helicopter mainshaft engine bearing for periods as long as 30 minutes.

The application of condensate water as an additional cooling media intermittently in condenser of a split air conditioning

NASA Astrophysics Data System (ADS)

Ardita, I. N.; Subagia, I. W. A.

2018-01-01

The condensate water produced by indoor a split air conditioning is usually not utilized and thrown away into the environment. The result of measurement shows that the temperature of condensate water produced by split air conditioning is quite low, that is 19-22 °C at the rate of 16-20 mL / min and it has PH balance. Under such conditions, Air Condensate produced by split air conditioning should still be recovered as an additional cooling medium on the condenser. This research will re-investigate the use of condensate water as an intermittent additional cooling of the condenser to increase the cooling capacity and performance of the air conditioning system. This research is done by experimental method whose implementation includes; designing and manufacturing of experimental equipment, mounting measuring tools, experimental data retrieval, data processing and yield analysis. The experimental results show that the use of condensate water as an intermittent additional cooling medium on split air conditioning condenser can increase the refrigeration effect about 2%, cooling capacity about 4% and 7% of COP system. Experimental results also show a decrease in power consumption in the system compressor about 3%

Liquid metal cooled nuclear reactors with passive cooling system

DOEpatents

Hunsbedt, Anstein; Fanning, Alan W.

1991-01-01

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of cooling medium flow circuits which cooperate to remove and carry heat away from the fuel core upon loss of the normal cooling flow circuit to areas external thereto.

Laboratory observations of biocide efficiency against Legionella in model cooling tower systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, W.M.; Eccles, J.; Fricker, C.

1999-07-01

The efficacy of specific oxidizing and non-oxidizing biocides was examined using a model cooling system inoculated with a microcosm containing an environmental isolate of Legionella pneumophila. The microcosm was prepared in a two-stage chemostat, which provided a consistent source of microbiological inoculum for the study. The microcosm consisted of both sessile (within biofilms) and planktonic Legionella in association with other microorganisms, including Pseudomonas species and cyst-forming ameobae. A procedure was established to successfully transfer the chemostat grown inoculum to the model cooling system and establish both sessile and planktonic forms of Legionella in the model cooling system. The greatest biocidalmore » effect for all of the biocides was observed immediately after dosing. This effect was relatively short-lived even for the slow acting biocides such isothiazolin (as 8 ppm active) where an effect was only observed over the first 12 hours. The faster acting biocides, DBNPA (as 8 ppm active) and gluteraldehyde (as 27 ppm active), did initially reduce Legionella populations but did not totally eliminate Legionella or provide lasting control. Chlorine and bromine (as 0.5--1.5 ppm free halogen), and ozone (as 0.1--0.5 ppm free reserve) reduced and controlled Legionella populations so long as a free reserve of oxidant was maintained. Legionella recovered quickly after biocide dosing, reestablishing similar levels to those observed before dosing.« less

Dry coolers and air-condensing units (Review)

NASA Astrophysics Data System (ADS)

Milman, O. O.; Anan'ev, P. A.

2016-03-01

The analysis of factors affecting the growth of shortage of freshwater is performed. The state and dynamics of the global market of dry coolers used at electric power plants are investigated. Substantial increase in number and maximum capacity of air-cooled condensers, which have been put into operation in the world in recent years, are noted. The key reasons facilitating the choice of developers of the dry coolers, in particular the independence of the location of thermal power plant from water sources, are enumerated. The main steam turbine heat removal schemes using air cooling are considered, their comparison of thermal efficiency is assessed, and the change of three important parameters, such as surface area of heat transfer, condensate pump flow, and pressure losses in the steam exhaust system, are estimated. It is shown that the most effective is the scheme of direct steam condensation in the heat-exchange tubes, but other schemes also have certain advantages. The air-cooling efficiency may be enhanced much more by using an air-cooling hybrid system: a combination of dry and wet cooling. The basic applied constructive solutions are shown: the arrangement of heat-exchange modules and the types of fans. The optimal mounting design of a fully shopassembled cooling system for heat-exchange modules is represented. Different types of heat-exchange tubes ribbing that take into account the operational features of cooling systems are shown. Heat transfer coefficients of the plants from different manufacturers are compared, and the main reasons for its decline are named. When using evaporative air cooling, it is possible to improve the efficiency of air-cooling units. The factors affecting the faultless performance of dry coolers (DC) and air-condensing units (ACU) and the ways of their elimination are described. A high velocity wind forcing reduces the efficiency of cooling systems and creates preconditions for the development of wind-driven devices. It is noted that global trends have a significant influence on the application of dry coolers in Russia, in view of the fact that some TPP have a surface condensers arrangement. The reasons that these systems are currently less efficient than the direct steam condensation in an air-cooled condenser are explained. It is shown that, in some cases, it is more reasonable to use mixing-type condensers in combination with a dry cooler. Measures for a full import substitution of steam exhaust heat removal systems are mentioned.

An experimental study on the design, performance and suitability of evaporative cooling system using different indigenous materials

NASA Astrophysics Data System (ADS)

Alam, Md. Ferdous; Sazidy, Ahmad Sharif; Kabir, Asif; Mridha, Gowtam; Litu, Nazmul Alam; Rahman, Md. Ashiqur

2017-06-01

The present study aimed to evaluate the feasibility of coconut coir pads, jute fiber pads and sackcloth pads as alternative pad materials. Experimental measurements were conducted and the experimental data were quantitative. The experimental work mainly focused on the effects of different types and thicknesses of evaporative cooling pads by using forced draft fan while changing the environmental conditions. Experiments are conducted in a specifically constructed test chamber having dimensions of 12'X8'X8', using a number of cooling pads (36"X26") with a variable thickness parameters of the evaporative cooling pads i.e., 50, 75 and 100 mm. Moreover, the experimental work involved the measurement of environmental parameters such as temperature, relative humidity, air velocity, water mass flow rate and pressure drops at different times during the day. Experiments were conducted at three different water mass flow rates (0.25 kgs-1, 0.40 kgs-1 & 0.55 kgs-1) and three different air velocities (3.6 ms-1, 4.6 ms-1& 5.6 ms-1). There was a significant difference between evaporative cooling pad types and cooling efficiency. The coconut coir pads yielded maximum cooling efficiency of 85%, whereas other pads yielded the following maximum cooling efficiency: jute fiber pads 78% and sackcloth 69% for higher air velocity and minimum mass flow rate. It is found that the maximum reduction in temperature between cooling pad inlet and outlet is 4°C with a considerable increase in humidity. With the increase of pad thickness there was an increment of cooling efficiency. The results obtained for environmental factors, indicated that there was a significant difference between environmental factors and cooling efficiency. In terms of the effect of air velocity on saturation efficiency and pressure drop, higher air velocity decreases saturation efficiency and increases pressure drop across the wetted pad for maximum flow rate. Convective heat transfer co-efficient has an almost linear relationship with air Velocity. Water consumption or evaporation rate increases with the increase in air velocity. Finally, the present study indicated that the coconut coir pads perform better than the other evaporative cooling pads and have higher potential as wetted-pad material. The outcomes of this study can provide an effective and low-cost solution in the form of evaporative cooling system, especially in an agricultural country like Bangladesh.

Passive cooling system for liquid metal cooled nuclear reactors with backup coolant flow path

DOEpatents

Hunsbedt, Anstein; Boardman, Charles E.

1993-01-01

A liquid metal cooled nuclear fission reactor plant having a passive auxiliary safety cooling system for removing residual heat resulting from fuel decay during reactor shutdown, or heat produced during a mishap. This reactor plant is enhanced by a backup or secondary passive safety cooling system which augments the primary passive auxiliary cooling system when in operation, and replaces the primary system when rendered inoperable.

Feasibility and Supply Analysis of U.S. Geothermal District Heating and Cooling System

NASA Astrophysics Data System (ADS)

He, Xiaoning

Geothermal energy is a globally distributed sustainable energy with the advantages of a stable base load energy production with a high capacity factor and zero SOx, CO, and particulates emissions. It can provide a potential solution to the depletion of fossil fuels and air pollution problems. The geothermal district heating and cooling system is one of the most common applications of geothermal energy, and consists of geothermal wells to provide hot water from a fractured geothermal reservoir, a surface energy distribution system for hot water transmission, and heating/cooling facilities to provide water and space heating as well as air conditioning for residential and commercial buildings. To gain wider recognition for the geothermal district heating and cooling (GDHC) system, the potential to develop such a system was evaluated in the western United States, and in the state of West Virginia. The geothermal resources were categorized into identified hydrothermal resources, undiscovered hydrothermal resources, near hydrothermal enhanced geothermal system (EGS), and deep EGS. Reservoir characteristics of the first three categories were estimated individually, and their thermal potential calculated. A cost model for such a system was developed for technical performance and economic analysis at each geothermally active location. A supply curve for the system was then developed, establishing the quantity and the cost of potential geothermal energy which can be used for the GDHC system. A West Virginia University (WVU) case study was performed to compare the competiveness of a geothermal energy system to the current steam based system. An Aspen Plus model was created to simulate the year-round campus heating and cooling scenario. Five cases of varying water flow rates and temperatures were simulated to find the lowest levelized cost of heat (LCOH) for the WVU case study. The model was then used to derive a levelized cost of heat as a function of the population density at a constant geothermal gradient. By use of such functions in West Virginia at a census tract level, the most promising census tracts in WV for the development of geothermal district heating and cooling systems were mapped. This study is unique in that its purpose was to utilize supply analyses for the GDHC systems and determine an appropriate economic assessment of the viability and sustainability of the systems. It was found that the market energy demand, production temperature, and project lifetime have negative effects on the levelized cost, while the drilling cost, discount rate, and capital cost have positive effects on the levelized cost by sensitivity analysis. Moreover, increasing the energy demand is the most effective way to decrease the levelized cost. The derived levelized cost function shows that for EGS based systems, the population density has a strong negative effect on the LCOH at any geothermal gradient, while the gradient only has a negative effect on the LCOH at a low population density.

Development of Personalized Radiant Cooling System for an Office Room

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khare, Vaibhav; Sharma, Anuj; Mathur, Jyotirmay

2015-01-01

The building industry nowadays is facing two major challenges increased concern for energy reduction and growing need for thermal comfort. These challenges have led many researchers to develop Radiant Cooling Systems that show a large potential for energy savings. This study aims to develop a personalized cooling system using the principle of radiant cooling integrated with conventional all-air system to achieve better thermal environment at the workspace. Personalized conditioning aims to create a microclimatic zone around a single workspace. In this way, the energy is deployed only where it is actually needed, and the individual s needs for thermal comfortmore » are fulfilled. To study the effect of air temperature along with air temperature distribution for workspace, air temperature near the vicinity of the occupant has been obtained as a result of Computational Fluid Dynamics (CFD) simulation using FLUENT. The analysis showed that personalized radiant system improves thermal environment near the workspace and allows all-air systems to work at higher thermostat temperature without compromising the thermal comfort, which in turn reduces its energy consumption.« less

Cooling During Exercise: An Overlooked Strategy for Enhancing Endurance Performance in the Heat.

PubMed

Stevens, Christopher J; Taylor, Lee; Dascombe, Ben J

2017-05-01

It is well established that endurance performance is negatively affected by environmental heat stress due to a complex interaction of physical, physiological and psychological alterations. Numerous scientific investigations have attempted to improve performance in the heat with pre-cooling (cooling prior to an exercise test), and as such this has become a well-established ergogenic practice for endurance athletes. However, the use of mid-cooling (cooling during an exercise test) has received considerably less research attention in comparison, despite recent evidence to suggest that the advantage gained from mid-cooling may outweigh that of pre-cooling. A range of mid-cooling strategies are beneficial for endurance performance in the heat, including the ingestion of cold fluids and ice slurry, both with and without menthol, as well as cooling of the neck and face region via a cooling collar or water poured on the head and face. The combination of pre-cooling and mid-cooling has also been effective, but few comparisons exist between the timing and type of such interventions. Therefore, athletes should experiment with a range of suitable mid-cooling strategies for their event during mock competition scenarios, with the aim to determine their individual tolerable limits and performance benefits. Based on current evidence, the effect of mid-cooling on core temperature appears largely irrelevant to any subsequent performance improvements, while cardiovascular, skin temperature, central nervous system function and psychophysiological factors are likely involved. Research is lacking on elite athletes, and as such it is currently unclear how this population may benefit from mid-cooling.

Measure Guideline: Ventilation Cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springer, D.; Dakin, B.; German, A.

2012-04-01

The purpose of this measure guideline is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

Integrated exhaust gas recirculation and charge cooling system

DOEpatents

Wu, Ko-Jen

2013-12-10

An intake system for an internal combustion engine comprises an exhaust driven turbocharger configured to deliver compressed intake charge, comprising exhaust gas from the exhaust system and ambient air, through an intake charge conduit and to cylinders of the internal combustion engine. An intake charge cooler is in fluid communication with the intake charge conduit. A cooling system, independent of the cooling system for the internal combustion engine, is in fluid communication with the intake charge cooler through a cooling system conduit. A coolant pump delivers a low temperature cooling medium from the cooling system to and through the intake charge cooler for the transfer of heat from the compressed intake charge thereto. A low temperature cooler receives the heated cooling medium through the cooling system conduit for the transfer or heat therefrom.

Provisioning cooling elements for chillerless data centers

DOEpatents

Chainer, Timothy J.; Parida, Pritish R.

2016-12-13

Systems and methods for cooling include one or more computing structure, an inter-structure liquid cooling system that includes valves configured to selectively provide liquid coolant to the one or more computing structures; a heat rejection system that includes one or more heat rejection units configured to cool liquid coolant; and one or more liquid-to-liquid heat exchangers that include valves configured to selectively transfer heat from liquid coolant in the inter-structure liquid cooling system to liquid coolant in the heat rejection system. Each computing structure further includes one or more liquid-cooled servers; and an intra-structure liquid cooling system that has valves configured to selectively provide liquid coolant to the one or more liquid-cooled servers.

Preliminary design package for solar heating and cooling systems

NASA Technical Reports Server (NTRS)

1978-01-01

Summarized preliminary design information on activities associated with the development, delivery and support of solar heating and cooling systems is given. These systems are for single family dwellings and commercial applications. The heating/cooling system use a reversible vapor compression heat pump that is driven in the cooling mode by a Rankine power loop, and in the heating mode by a variable speed electric motor. The heating/cooling systems differ from the heating-only systems in the arrangement of the heat pump subsystem and the addition of a cooling tower to provide the heat sink for cooling mode operation.

Analysis of Radiant Cooling System Configurations Integrated with Cooling Tower for Different Indian Climatic Zones

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathur, Jyotirmay; Bhandari, Mahabir S; Jain, Robin

Radiant cooling system has proven to be a low energy consumption system for building cooling needs. This study describes the use of cooling tower in radiant cooling system to improve the overall system efficiency. A comprehensive simulation feasibility study of the application of cooling tower in radiant cooling system was performed for the fifteen cities in different climatic zones of India. It was found that in summer, the wet bulb temperature (WBT) of the different climatic zones except warm-humid is suitable for the integration of cooling tower with radiant cooling system. In these climates, cooling tower can provide on averagemore » 24 C to 27 C water In order to achieve the energy saving potential, three different configurations of radiant cooling system have been compared in terms of energy consumption. The different configurations of the radiant cooling system integrated with cooling tower are: (1) provide chilled water to the floor, wall and ceiling mounted tubular installation. (2) provide chilled water to the wall and ceiling mounted tabular installation. In this arrangement a separate chiller has also been used to provide chilled water at 16 C to the floor mounted tubular installation. (3) provide chilled water to the wall mounted tabular installation and a separate chiller is used to provide chilled water at 16 C to the floor and ceiling mounted tabular installation. A dedicated outdoor air system is also coupled for dehumidification and ventilation in all three configurations. A conventional all-air system was simulated as a baseline to compare these configurations for assessing the energy saving potential.« less

Cost analysis of an ammonia dry cooling system with a Chicago Bridge and Iron peak shaving system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drost, M.K.; Johnson, B.M.

1980-12-01

A study was performed to determine the potential for reducing the cost associated with dry cooling by using an ammonia dry cooling system augmented with the Chicago Bridge and Iron (CP and I) peak shaving system. The cost analysis of an all-dry ammonia cooling system operating in conjunction with a peak shaving system is documented. The peak shaving system utilizes the excess cooling capability available at night to cool water to be used for supplemental cooling during the following day. The analysis consisted of determining the incremental cost of cooling for the CB and I system and comparing this costmore » to the incremental cost of cooling for both dry and wet/dry systems for a consistent set of design conditions and assumptions. The wet/dry systems were analyzed over a range of water usages. The basis of the comparisons was a cooling system designed for installations with a 650 mWe (gross) coal-fired power plant. From results of the study it was concluded that: the CB and I system shows a substantial economic advantage when compared with an all-dry cooling system; the CB and I system appears to be competitive with wet/dry cooling systems using about 2 to 3% water; and the CB and I system demonstrates a clear economic advantage when compared to both dry and wet/dry concepts for a winter peaking utility where the excess generation is assumed to displace both base-loaded coal-fired power generation and oil-fired gas turbine peaking units.« less

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT IV, MAINTAINING THE COOLING SYSTEM--DETROIT DIESEL ENGINES.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF THE DIESEL ENGINE COOLING SYSTEM. TOPICS ARE PURPOSE OF THE COOLING SYSTEM, CARE MAINTENANCE OF THE COOLING SYSTEM, COOLING SYSTEM COMPONENTS, AND TROUBLESHOOTING TIPS. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL BRANCH PROGRAMED TRAINING…

Thermal Propulsion Capture System Heat Exchanger Design

NASA Technical Reports Server (NTRS)

Richard, Evan M.

2016-01-01

One of the biggest challenges of manned spaceflight beyond low earth orbit and the moon is harmful radiation that astronauts would be exposed to on their long journey to Mars and further destinations. Using nuclear energy has the potential to be a more effective means of propulsion compared to traditional chemical engines (higher specific impulse). An upper stage nuclear engine would allow astronauts to reach their destination faster and more fuel efficiently. Testing these engines poses engineering challenges due to the need to totally capture the engine exhaust. The Thermal Propulsion Capture System is a concept for cost effectively and safely testing Nuclear Thermal Engines. Nominally, hydrogen exhausted from the engine is not radioactive, but is treated as such in case of fuel element failure. The Thermal Propulsion Capture System involves injecting liquid oxygen to convert the hydrogen exhaust into steam. The steam is then cooled and condensed into liquid water to allow for storage. The Thermal Propulsion Capture System concept for ground testing of a nuclear powered engine involves capturing the engine exhaust to be cooled and condensed before being stored. The hydrogen exhaust is injected with liquid oxygen and burned to form steam. That steam must be cooled to saturation temperatures before being condensed into liquid water. A crossflow heat exchanger using water as a working fluid will be designed to accomplish this goal. Design a cross flow heat exchanger for the Thermal Propulsion Capture System testing which: Eliminates the need for water injection cooling, Cools steam from 5800 F to saturation temperature, and Is efficient and minimizes water requirement.

Thermoregulatory responses of Holstein and Brown Swiss Heat-Stressed dairy cows to two different cooling systems

NASA Astrophysics Data System (ADS)

Correa-Calderon, Abelardo; Armstrong, Dennis; Ray, Donald; DeNise, Sue; Enns, Mark; Howison, Christine

. Thirty-seven Holstein and 26 Brown Swiss dairy cows were used to evaluate the effect of two different cooling systems on physiological and hormonal responses during the summer. A control group of cows had access only to shade (C). A second group was cooled with spray and fans (S/F) and the third group was under an evaporative cooling system called Korral Kool (KK). The maximum temperature humidity index during the trial was from 73 to 85. Rectal temperatures and respiration rates of the C group were higher (P < 0.05) than those of the S/F and KK groups in both Holstein and Brown Swiss cows. Triiodothyronine levels in milk were higher (P < 0.05) in the KK group than in the S/F and C groups, while cortisol levels were lower (P < 0.05) in the C group than in S/F and KK. There was no significant difference in the hormonal response of the two breeds. These results demonstrate that both cooling systems may be used increase the comfort of Holstein and Brown Swiss cows during summer in hot, dry climates.

Database Reorganization in Parallel Disk Arrays with I/O Service Stealing

NASA Technical Reports Server (NTRS)

Zabback, Peter; Onyuksel, Ibrahim; Scheuermann, Peter; Weikum, Gerhard

1996-01-01

We present a model for data reorganization in parallel disk systems that is geared towards load balancing in an environment with periodic access patterns. Data reorganization is performed by disk cooling, i.e. migrating files or extents from the hottest disks to the coldest ones. We develop an approximate queueing model for determining the effective arrival rates of cooling requests and discuss its use in assessing the costs versus benefits of cooling.

Advanced Design Heat PumpRadiator for EVA Suits

NASA Technical Reports Server (NTRS)

Izenson, Michael G.; Chen, Weibo; Passow, Christian; Phillips, Scott; Trevino, Luis

2009-01-01

Absorption cooling using a LiCl/water heat pump can enable lightweight and effective thermal control for EVA suits without venting water to the environment. The key components in the system are an absorber/radiator that rejects heat to space and a flexible evaporation cooling garment that absorbs heat from the crew member. This paper describes progress in the design, development, and testing of the absorber/radiator and evaporation cooling garment. New design concepts and fabrication approaches will significantly reduce the mass of the absorber/radiator. We have also identified materials and demonstrated fabrication approaches for production of a flexible evaporation cooling garment. Data from tests of the absorber/radiator s modular components have validated the design models and allowed predictions of the size and weight of a complete system.

Gearing Up for the Big Game...and More

NASA Technical Reports Server (NTRS)

2004-01-01

Bill Elkins, a member of the U.S. Space Foundation's Space Technology Hall of Fame, is using his experience in developing cooling garments for use in sports and medicine. His company, CoolSystems, has developed the Game Ready[TM] Accelerated Recovery System. Game Ready[TM] ergonomic wraps are designed to custom fit the ankle, knee, back, torso, shoulder, elbow, and wrist and provide deep tissue cooling therapy with intermittent compression to reduce pain, swelling, and tissue damage. Recharge[TM] cooling garments have been developed to lower core body temperature in people with heat-sensitive multiple sclerosis, reducing symptoms such as fatigue, decreased balance, impaired vision, and decreased endurance. The company currently is collaborating with Stanford University Medical Center's Stanford Stroke Center to investigate the effectiveness of discrete hypothermia in stroke and head trauma patients.

Development of an experimental system for characterization of high-temperature superconductors cooled by liquid hydrogen under the external magnetic field

NASA Astrophysics Data System (ADS)

Tatsumoto, H.; Shirai, Y.; Shiotsu, M.; Naruo, Y.; Kobayashi, H.; Inatani, Y.

2014-05-01

An experimental system has been developed to investigate electro-magnetic properties of high-Tc superconductors cooled by liquid hydrogen under the external magnetic field of up to 7 T. A LH2 cryostat is concentrically mounted on the inside of a LHe cryostat to cool a NbTi superconducting magnet. The experimental system is installed in an explosion-proof room. Explosion proof electrical devices are used and current leads are covered with an enclosure filled with nitrogen gas. A remote control system has been developed. Furthermore, the effects of stray magnetic field on the existing and the new devices are investigated and electro-magnetic shielding panels and enclosure made of iron were designed. It is confirmed through the cryogenic test that the experimental system meets the design requirements.

Thermal modeling of a secondary concentrator integrated with an open direct-absorption molten-salt volumetric receiver in a beam-down tower system

NASA Astrophysics Data System (ADS)

Lahlou, Radia; Armstrong, Peter; Grange, Benjamin; Almheiri, Saif; Calvet, Nicolas; Slocum, Alexander; Shamim, Tariq

2016-05-01

An upward-facing three-dimensional secondary concentrator, herein termed Final Optical Element (FOE), is designed to be used in a beam-down tower in combination with an open volumetric direct-absorption molten-salt receiver tank acting simultaneously as a thermal energy storage system. It allows reducing thermal losses from the open receiver by decreasing its aperture area while keeping minimal spillage losses. The FOE is exposed to high solar fluxes, a part of which is absorbed by its reflector material, leading to material degradation by overheating. Consequently, the FOE may require active cooling. A thermal model of the FOE under passive cooling mechanism is proposed as a first step to evaluate its sensitivity to some design parameters. Then, it will be used to evaluate the requirements for the active cooling system. The model provides insights on the FOE thermal behavior and highlights the effectiveness of a design modification on passive cooling enhancement. First prototype tests under reduced flux and with no active cooling will be used for model adjustment.

Provisioning cooling elements for chillerless data centers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chainer, Timothy J.; Parida, Pritish R.

Systems and methods for cooling include one or more computing structure, an inter-structure liquid cooling system that includes valves configured to selectively provide liquid coolant to the one or more computing structures; a heat rejection system that includes one or more heat rejection units configured to cool liquid coolant; and one or more liquid-to-liquid heat exchangers that include valves configured to selectively transfer heat from liquid coolant in the inter-structure liquid cooling system to liquid coolant in the heat rejection system. Each computing structure further includes one or more liquid-cooled servers; and an intra-structure liquid cooling system that has valvesmore » configured to selectively provide liquid coolant to the one or more liquid-cooled servers.« less

A Techno-Economic Assessment of Hybrid Cooling Systems for Coal- and Natural-Gas-Fired Power Plants with and without Carbon Capture and Storage.

PubMed

Zhai, Haibo; Rubin, Edward S

2016-04-05

Advanced cooling systems can be deployed to enhance the resilience of thermoelectric power generation systems. This study developed and applied a new power plant modeling option for a hybrid cooling system at coal- or natural-gas-fired power plants with and without amine-based carbon capture and storage (CCS) systems. The results of the plant-level analyses show that the performance and cost of hybrid cooling systems are affected by a range of environmental, technical, and economic parameters. In general, when hot periods last the entire summer, the wet unit of a hybrid cooling system needs to share about 30% of the total plant cooling load in order to minimize the overall system cost. CCS deployment can lead to a significant increase in the water use of hybrid cooling systems, depending on the level of CO2 capture. Compared to wet cooling systems, widespread applications of hybrid cooling systems can substantially reduce water use in the electric power sector with only a moderate increase in the plant-level cost of electricity generation.

Practices for Alleviating Heat Stress of Dairy Cows in Humid Continental Climates: A Literature Review

PubMed Central

Fournel, Sébastien; Ouellet, Véronique; Charbonneau, Édith

2017-01-01

Simple Summary The severity of heat stress issues on dairy cows will increase as global warming progresses. Fortunately, major advances in environmental management, including fans, misters, sprinklers, and cooled waterbeds, can attenuate the effects of thermal stress on cow health, production, and reproduction. These cooling systems were, however, tested in subtropical areas and their efficiency in northern regions is uncertain. This article assesses the potential of existing technologies to cool cows in humid continental climates through calculation of heat stress indices. Abstract Heat stress negatively affects the health and performance of dairy cows, resulting in considerable economic losses for the industry. In future years, climate change will exacerbate these losses by making the climate warmer. Physical modification of the environment is considered to be the primary means of reducing adverse effects of hot weather conditions. At present, to reduce stressful heat exposure and to cool cows, dairy farms rely on shade screens and various forms of forced convection and evaporative cooling that may include fans and misters, feed-line sprinklers, and tunnel- or cross-ventilated buildings. However, these systems have been mainly tested in subtropical areas and thus their efficiency in humid continental climates, such as in the province of Québec, Canada, is unclear. Therefore, this study reviewed the available cooling applications and assessed their potential for northern regions. Thermal stress indices such as the temperature-humidity index (THI) were used to evaluate the different cooling strategies. PMID:28468329

Cooled radiofrequency denervation for treatment of sacroiliac joint pain: two-year results from 20 cases

PubMed Central

Ho, Kok-Yuen; Hadi, Mohamed Abdul; Pasutharnchat, Koravee; Tan, Kian-Hian

2013-01-01

Background Sacroiliac joint pain is a common cause of chronic low back pain. Different techniques for radiofrequency denervation of the sacroiliac joint have been used to treat this condition. However, results have been inconsistent because the variable sensory supply to the sacroiliac joint is difficult to disrupt completely using conventional radiofrequency. Cooled radiofrequency is a novel technique that uses internally cooled radiofrequency probes to enlarge lesion size, thereby increasing the chance of completely denervating the sacroiliac joint. The objective of this study was to evaluate the efficacy of cooled radiofrequency denervation using the SInergy™ cooled radiofrequency system for sacroiliac joint pain. Methods The charts of 20 patients with chronic sacroiliac joint pain who had undergone denervation using the SInergy™ cooled radiofrequency system were reviewed at two years following the procedure. Outcome measures included the Numeric Rating Scale for pain intensity, Patient Global Impression of Change, and Global Perceived Effect for patient satisfaction. Results Fifteen of 20 patients showed a significant reduction in pain (a decrease of at least three points on the Numeric Rating Scale). Mean Numeric Rating Scale for pain decreased from 7.4 ± 1.4 to 3.1 ± 2.5, mean Patient Global Impression of Change was “improved” (1.4 ± 1.5), and Global Perceived Effect was reported to be positive in 16 patients at two years following the procedure. Conclusion Cooled radiofrequency denervation showed long-term efficacy for up to two years in the treatment of sacroiliac joint pain. PMID:23869175

Solar-Cooled Hotel in the Virgin Islands

NASA Technical Reports Server (NTRS)

Harber, H.

1982-01-01

Performance of solar cooling system is described in 21-page report. System provides cooling for public areas including ball rooms, restaurant, lounge, lobby and shops. Chilled water from solar-cooling system is also used to cool hot water from hotel's desalinization plant.

On enhancing energy harvesting performance of the photovoltaic modules using an automatic cooling system and assessing its economic benefits of mitigating greenhouse effects on the environment

NASA Astrophysics Data System (ADS)

Wang, Jen-Cheng; Liao, Min-Sheng; Lee, Yeun-Chung; Liu, Cheng-Yue; Kuo, Kun-Chang; Chou, Cheng-Ying; Huang, Chen-Kang; Jiang, Joe-Air

2018-02-01

The performance of photovoltaic (PV) modules under outdoor operation is greatly affected by their location and environmental conditions. The temperature of a PV module gradually increases as it is exposed to solar irradiation, resulting in degradation of its electrical characteristics and power generation efficiency. This study adopts wireless sensor network (WSN) technology to develop an automatic water-cooling system for PV modules in order to improve their PV power generation efficiency. A temperature estimation method is developed to quickly and accurately estimate the PV module temperatures based on weather data provided from the WSN monitoring system. Further, an estimation method is also proposed for evaluation of the electrical characteristics and output power of the PV modules, which is performed remotely via a control platform. The automatic WSN-based water-cooling mechanism is designed to avoid the PV module temperature from reaching saturation. Equipping each PV module with the WSN-based cooling system, the ambient conditions are monitored automatically so that the temperature of the PV module is controlled by sprinkling water on the panel surface. The field-test experiment results show an increase in the energy harvested by the PV modules of approximately 17.75% when using the proposed WSN-based cooling system.

Demand Shifting with Thermal Mass in Large Commercial Buildings in a California Hot Climate Zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Peng; Yin, Rongxin; Brown, Carrie

2009-06-01

The potential for using building thermal mass for load shifting and peak energy demand reduction has been demonstrated in a number of simulation, laboratory, and field studies. Previous Lawrence Berkeley National Laboratory research has demonstrated that the approach is very effective in cool and moderately warm climate conditions (California Climate Zones 2-4). However, this method had not been tested in hotter climate zones. This project studied the potential of pre-cooling the building early in the morning and increasing temperature setpoints during peak hours to reduce cooling-related demand in two typical office buildings in hotter California climates ? one in Visaliamore » (CEC Climate Zone 13) and the other in San Bernardino (CEC Climate Zone 10). The conclusion of the work to date is that pre-cooling in hotter climates has similar potential to that seen previously in cool and moderate climates. All other factors being equal, results to date indicate that pre-cooling increases the depth (kW) and duration (kWh) of the possible demand shed of a given building. The effectiveness of night pre-cooling in typical office building under hot weather conditions is very limited. However, night pre-cooling is helpful for office buildings with an undersized HVAC system. Further work is required to duplicate the tests in other typical buildings and in other hot climate zones and prove that pre-cooling is truly effective.« less

Metallographic Cooling Rates of IAB Iron Meteorites

NASA Astrophysics Data System (ADS)

Meibom, A.; Haack, H.; Jensen, S. K.; Ulff-Moller, F.; Rasmussen, K. L.

1995-09-01

Non-metals can play an important role for the diffusion-controlled growth of the Widmanstatten structure in iron meteorites. The presence of P significantly changes the diffusivity and equilibrium concentration of Ni in kamacite and taenite [1,2], and the effects of P have therefore been included in metallographic cooling rate calculations for many years. The presence of C probably increases the diffusivity of Ni in taenite up to a factor of two, which is considerably smaller than the effect of P that increases the Ni diffusivity by up to a factor of 10 [3,1]. On the other hand, C partitions strongly into taenite leaving kamacite essentially C-free (<10 micrograms/g [4]) and significantly reduces the equilibrium Ni-concentration in taenite [5]. Therefore, the effect of C should be included in metallographic cooling rate calculations of C-rich iron meteorites [6]. IAB iron meteorites have much higher bulk C-concentrations than most other iron meteorites and the metallic phases of the IAB irons were probably saturated with C soon after kamacite nucleation commenced. Since C is expected to decrease the solubility of P in taenite [7] we have based our cooling rate estimate of Toluca (IAB) on the Fe-Ni-C system rather than the Fe-Ni-P system. Previous metallographic cooling rates determined for IAB irons, including the effect of P, are low (1-10 degrees C/My [8] and 30-70 degrees C/My [9]). Fractional crystallization of S-rich cores [10, 11] and impact generated melt pools [12] have been proposed as origins of the IAB iron meteorites. Since we expect melt pools near the surface to have cooled significantly faster than the core of a differentiated parent body, the metallographic cooling rates may be used to discriminate between the two models. We have performed thermodynamic calculations on the C-saturated Fe-Ni-C-system at temperatures above 400 degrees C [13]. The results agree with earlier experimental work [5] and indicate that C, to the same degree as P, reduces the Ni concentration of taenite coexisting with kamacite. We did not extend the thermodynamic calculations below 400 degrees C due to the lack of data. Therefore, our cooling rate estimates are based on taenite lamellae wider than about 10 micrometers which are largely sensitive to the cooling rate above around 400 degrees C. Our preliminary results show a slightly better match between calculated and measured Ni mid-profile-concentrations versus total-lamella-width for Toluca (IAB) using the Fe-Ni-C system than using the Fe-Ni-P system. This difference is mainly due to a lower diffusivity of Ni in taenite in the Fe-Ni-C system. The average cooling rate obtained for Toluca using the Fe-Ni-C system is approximately a factor of 5 lower than the cooling rate obtained on the basis of the Fe-Ni-P system. However, both lie in the range 1-15 degrees C/My which is consistent with cooling rate estimates based on Pu-fission tracks in silicate inclusions of Landes and Copiapo; both IAB [13]. These relatively low cooling rate is in discordance with a melt-pool origin of the IAB iron meteorites. References: [1] Dean D. C. and Goldstein J. I. (1986) Metall. Trans., 17A, 1131-1138. [2] Romig A. D. and Goldstein J. I. (1980) Metall. Trans. A, 11A, 1151-1159. [3] Wells C. and Mehl R. F. (1941) Trans. AIME, 145, 329-339. [4] Makjanic J. et al. (1988) NIMB, B30, 466-469. [5] Romig A. D. and Goldstein J. I. (1978) Metall. Trans., 9A, 1599-1609. [6] Meibom et al. (1994) Meteoritics, 29, 501. [7] Buchwald, personal communication. [8] Rasmussen K. L. (1989) Phys. Scripta, 39, 410-416. [9] Herpfer M. A. et al., GCA, 58, 1353-1365. [10] Kracher A. (1985) Proc. LPSC 15th, in JGR, 90, C689-C698. [11] McCoy T. et al. (1993) Meteoritics, 28, 552-560. [12] Choi B.-G. et al. (1995) GCA, 59, 593-612. [13] Sundman. B., Manual to Thermo-Calc, Royal Institute of Technology, Stockholm. [14] Benkheiri et al. (1979) Icarus, 40, 497-501.

Evaluation of the effects of the Morgantown SES cooling system on spawning and nursery areas of representative important species. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polgar, T.T.; Summers, J.K.; Haire, M.S.

1979-10-01

Power plant cooling system entrainment and plume entrainment may reduce the sizes of fish, benthic and other populations through the destruction of early life stages. This document has been prepared to estimate the potential effects and impacts of entrainment by the Morgantown (PEPCO) and Possum Point (VEPCO) steam electric generating stations. Maryland water quality regulation requires the determination of entrainment effects on spawning and nursery areas of consequence for the Representative Important Species (RIS) designated within the regulation. The purpose of this evaluation is to provide information for regulatory decisions regarding the need for alternative cooling modes at existing facilities.more » Caclulation schemes are presented to estimate the individual and cumulative entrainment effects due to the operations of both the Morgantown and Possum Point facilities. Potential adult population losses due to the entrainment of early life stages were estimated for 24 RIS populations.« less

Mechano-caloric cooling device

NASA Technical Reports Server (NTRS)

Frederking, T. H. K.; Luna, Jack; Abbassi, P.; Carandang, R. M.

1989-01-01

The mechano-caloric effect is potentially useful in the He II temperature range. Aside from demonstration work, little quantification effort appears to have been known since other refrigeration possibilities have been available for some time. Successful He II use-related system examples are as follows: in space, the utilization of the latent heat of vaporization has been quite successful in vapor-liquid phase separation (VLPS) in conjunction with thermomechanical force application in plugs. In magnet cooling systems, the possibility of using the mechano-caloric cooling effect in conjunction with thermo-mechanical circulation pump schemes, has been assessed (but not quantified yet to the extent desirable). A third example is quoted in conjunction with superfluid wind tunnel studies and liquid helium tow tank for surface vessels respectively. In all of these (partially future) R and D areas, the question of refrigerator effectiveness using the mechano-caloric effect appears to be relevant, possibly in conjunction with questions of reliability and simplicity. The present work is concerned with quantification of phenomena including simplified thermodynamic cycle calculations.

Navier-Stokes Simulation of Airconditioning Facility of a Large Modem Computer Room

NASA Technical Reports Server (NTRS)

2005-01-01

NASA recently assembled one of the world's fastest operational supercomputers to meet the agency's new high performance computing needs. This large-scale system, named Columbia, consists of 20 interconnected SGI Altix 512-processor systems, for a total of 10,240 Intel Itanium-2 processors. High-fidelity CFD simulations were performed for the NASA Advanced Supercomputing (NAS) computer room at Ames Research Center. The purpose of the simulations was to assess the adequacy of the existing air handling and conditioning system and make recommendations for changes in the design of the system if needed. The simulations were performed with NASA's OVERFLOW-2 CFD code which utilizes overset structured grids. A new set of boundary conditions were developed and added to the flow solver for modeling the roomls air-conditioning and proper cooling of the equipment. Boundary condition parameters for the flow solver are based on cooler CFM (flow rate) ratings and some reasonable assumptions of flow and heat transfer data for the floor and central processing units (CPU) . The geometry modeling from blue prints and grid generation were handled by the NASA Ames software package Chimera Grid Tools (CGT). This geometric model was developed as a CGT-scripted template, which can be easily modified to accommodate any changes in shape and size of the room, locations and dimensions of the CPU racks, disk racks, coolers, power distribution units, and mass-storage system. The compute nodes are grouped in pairs of racks with an aisle in the middle. High-speed connection cables connect the racks with overhead cable trays. The cool air from the cooling units is pumped into the computer room from a sub-floor through perforated floor tiles. The CPU cooling fans draw cool air from the floor tiles, which run along the outside length of each rack, and eject warm air into the center isle between the racks. This warm air is eventually drawn into the cooling units located near the walls of the room. One major concern is that the hot air ejected to the middle isle might recirculate back into the cool rack side and cause thermal short-cycling. The simulations analyzed and addressed the following important elements of the computer room: 1) High-temperature build-up in certain regions of the room; 2) Areas of low air circulation in the room; 3) Potential short-cycling of the computer rack cooling system; 4) Effectiveness of the perforated cooling floor tiles; 5) Effect of changes in various aspects of the cooling units. Detailed flow visualization is performed to show temperature distribution, air-flow streamlines and velocities in the computer room.

Use of cooling air heat exchangers as replacements for hot section strategic materials

NASA Technical Reports Server (NTRS)

Gauntner, J. W.

1983-01-01

Because of financial and political constraints, strategic aerospace materials required for the hot section of future engines might be in short supply. As an alternative to these strategic materials, this study examines the use of a cooling air heat exchanger in combination with less advanced hot section materials. Cycle calculations are presented for future turbofan systems with overall pressure ratios to 65, bypass ratios near 13, and combustor exit temperatures to 3260 R. These calculations quantify the effect on TSFC of using a decreased materials technology in a turbofan system. The calculations show that the cooling air heat exchanger enables the feasibility of these engines.

A comparison of fuel savings in the residential and commercial sectors generated by the installation of solar heating and cooling systems under three tax credit scenarios

NASA Astrophysics Data System (ADS)

Moden, R.

An analysis of expected energy savings between 1977 and 1980 under three different solar tax credit scenarios is presented. The results were obtained through the solar heating and cooling of buildings (SHACOB) commercialization model. This simulation provides projected savings of conventional fuels through the installation of solar heating and cooling systems on buildings in the residential and commercial sectors. The three scenarios analyzed considered the tax credits contained in the Windfall Profits Tax of April 1980, the National Tax Act of November 1978, and a case where no tax credit is in effect.

Low pressure cooling seal system for a gas turbine engine

DOEpatents

Marra, John J

2014-04-01

A low pressure cooling system for a turbine engine for directing cooling fluids at low pressure, such as at ambient pressure, through at least one cooling fluid supply channel and into a cooling fluid mixing chamber positioned immediately downstream from a row of turbine blades extending radially outward from a rotor assembly to prevent ingestion of hot gases into internal aspects of the rotor assembly. The low pressure cooling system may also include at least one bleed channel that may extend through the rotor assembly and exhaust cooling fluids into the cooling fluid mixing chamber to seal a gap between rotational turbine blades and a downstream, stationary turbine component. Use of ambient pressure cooling fluids by the low pressure cooling system results in tremendous efficiencies by eliminating the need for pressurized cooling fluids for sealing this gap.

Turbine airfoil with ambient cooling system

DOEpatents

Campbell, Jr, Christian X.; Marra, John J.; Marsh, Jan H.

2016-06-07

A turbine airfoil usable in a turbine engine and having at least one ambient air cooling system is disclosed. At least a portion of the cooling system may include one or more cooling channels configured to receive ambient air at about atmospheric pressure. The ambient air cooling system may have a tip static pressure to ambient pressure ratio of at least 0.5, and in at least one embodiment, may include a tip static pressure to ambient pressure ratio of between about 0.5 and about 3.0. The cooling system may also be configured such that an under root slot chamber in the root is large to minimize supply air velocity. One or more cooling channels of the ambient air cooling system may terminate at an outlet at the tip such that the outlet is aligned with inner surfaces forming the at least one cooling channel in the airfoil to facilitate high mass flow.

MODELING THE AMBIENT CONDITION EFFECTS OF AN AIR-COOLED NATURAL CIRCULATION SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Rui; Lisowski, Darius D.; Bucknor, Matthew

The Reactor Cavity Cooling System (RCCS) is a passive safety concept under consideration for the overall safety strategy of advanced reactors such as the High Temperature Gas-Cooled Reactor (HTGR). One such variant, air-cooled RCCS, uses natural convection to drive the flow of air from outside the reactor building to remove decay heat during normal operation and accident scenarios. The Natural convection Shutdown heat removal Test Facility (NSTF) at Argonne National Laboratory (“Argonne”) is a half-scale model of the primary features of one conceptual air-cooled RCCS design. The facility was constructed to carry out highly instrumented experiments to study the performancemore » of the RCCS concept for reactor decay heat removal that relies on natural convection cooling. Parallel modeling and simulation efforts were performed to support the design, operation, and analysis of the natural convection system. Throughout the testing program, strong influences of ambient conditions were observed in the experimental data when baseline tests were repeated under the same test procedures. Thus, significant analysis efforts were devoted to gaining a better understanding of these influences and the subsequent response of the NSTF to ambient conditions. It was determined that air humidity had negligible impacts on NSTF system performance and therefore did not warrant consideration in the models. However, temperature differences between the building exterior and interior air, along with the outside wind speed, were shown to be dominant factors. Combining the stack and wind effects together, an empirical model was developed based on theoretical considerations and using experimental data to correlate zero-power system flow rates with ambient meteorological conditions. Some coefficients in the model were obtained based on best fitting the experimental data. The predictive capability of the empirical model was demonstrated by applying it to the new set of experimental data. The empirical model was also implemented in the computational models of the NSTF using both RELAP5-3D and STARCCM+ codes. Accounting for the effects of ambient conditions, simulations from both codes predicted the natural circulation flow rates very well.« less

Advanced Heat Exchangers for Dry Cooling Systems, Phase II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fortini, Arthur J.; Horwath, Joseph

Dry cooling systems are an option for industrial and utility power plants that cannot obtain permits for cooling water or where cooling water is unavailable. Currently available dry cooling systems are more expensive and less efficient than wet cooling systems, so significant improvements in efficiency are needed to make them economically viable. Previous attempts at using foams as cooling fin materials for power generating systems have focused on high thermal conductivity graphite foams made via the Oak Ridge process. Because these materials have high flow restrictions and hence low permeability with respect to air flow, their internal volume and surfacemore » area were not effectively used. Consequently, they performed poorly and offered no advantage over aluminum fins. A foam with a more open structure would provide increased permeability, enable greater airflow through the bulk material, increase the rate of heat transfer, and enable the material to outperform traditional fin structures. In this project, Ultramet designed, fabricated, and tested low flow restriction, high-efficiency foam-based heat exchangers. Calculations based on existing thermal and hydraulic data for Ultramet’s high-performance open-cell foams indicated that 65-ppi (pores per linear inch) pyrolytic graphite foam with a relative density of 15 vol%, produced by chemical vapor infiltration (CVI), would have an effectiveness significantly greater than that of a state-of-the-art Hamon/Balcke-Durr aluminum fin system and greater than that of the POCO graphite foams previously tested for the DOE National Energy Technology Laboratory. Using the same chevron design, test setup, and run conditions as were used with the Hamon/Balcke-Durr fin system and the POCO foams, Ultramet tested graphite foams with air flow velocities of 0.07–3.2 m/sec and pressure drops of 0.03–9.7 inH2O. The best-performing graphite foam architectures had air velocities in excess of 2.5 m/sec when the pressure drop was 1 inH2O. Because a foam-based system is more efficient than a fin-based system, a smaller heat exchanger installation can be used, significantly reducing the installation cost. Furthermore, because the foam-based system is physically smaller with no increase in flow restriction, less electrical power is needed to run the fans to drive the air through the condenser. The result is a decrease in both the installation and operating costs, which in turn will decrease the overall life cycle cost of the system.« less

THE COOLING REQUIREMENTS AND PROCESS SYSTEMS OF THE SOUTH AFRICAN RESEARCH REACTOR, SAFARI 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colley, J.R.

1962-12-01

The SAFARI 1 research reactor is cooled and moderated by light water. There are three process systems, a primary water system which cools the reactor core and surroundings, a pool water system, and a secondary water system which removes the heat from the primary and pool systems. The cooling requirements for the reactor core and experimental facilities are outlined, and the cooling and purification functions of the three process systems are described. (auth)

Thermal Design and Analysis of a Multi-Stage 30K Radiative Cooling System for EPIC

NASA Technical Reports Server (NTRS)

Chui, Talso; Bock, Jamie; Holmes, Warren; Raab, Jeff

2009-01-01

The Experimental Probe of Inflationary Cosmology (EPIC) is an implementation of the NASA Einstein Inflation Probe mission, to answer questions about the physics of Inflation in the early Universe by measuring the polarization of the Cosmic Microwave Background (CMB). The mission relies on a passive cooling system to cool the enclosure of a telescope to 30 K; a cryocooler then cools this enclosure to 18 K and the telescope to 4 K. Subsequently, an adiabatic demagnetization refrigerator further cools a large focal plane to approx.100 mK. For this mission, the telescope has an aperture of 1.4 m, and the spacecraft's symmetry axis is oriented approx. 45 degrees relative to the direction of the sun. The spacecraft will be spun at approx. 0.5 rpm around this axis, which then precesses on the sky at 1 rph. The passive system must both supply the necessary cooling power for the cryocooler and meet demanding temperature stability requirements. We describe the thermal design of a passive cooling system consisting of four V-groove radiators for shielding of solar radiation and cooling the telescope to 30 K. The design realizes loads of 20 and 68 mW at the 4 K and 18 K stages on the cooler, respectively. A lower cost option for reaching 40 K with three V-groove radiators is also described. The analysis includes radiation coupling between stages of the radiators and sunshields, and parasitic conduction in the bipod support, harnesses, and ADR leads. Dynamic effects are also estimated, including the very small variations in temperature due to the scan motion of the spacecraft.

Design and Control of Hydronic Radiant Cooling Systems

NASA Astrophysics Data System (ADS)

Feng, Jingjuan

Improving energy efficiency in the Heating Ventilation and Air conditioning (HVAC) systems in buildings is critical to achieve the energy reduction in the building sector, which consumes 41% of all primary energy produced in the United States, and was responsible for nearly half of U.S. CO2 emissions. Based on a report by the New Building Institute (NBI), when HVAC systems are used, about half of the zero net energy (ZNE) buildings report using a radiant cooling/heating system, often in conjunction with ground source heat pumps. Radiant systems differ from air systems in the main heat transfer mechanism used to remove heat from a space, and in their control characteristics when responding to changes in control signals and room thermal conditions. This dissertation investigates three related design and control topics: cooling load calculations, cooling capacity estimation, and control for the heavyweight radiant systems. These three issues are fundamental to the development of accurate design/modeling tools, relevant performance testing methods, and ultimately the realization of the potential energy benefits of radiant systems. Cooling load calculations are a crucial step in designing any HVAC system. In the current standards, cooling load is defined and calculated independent of HVAC system type. In this dissertation, I present research evidence that sensible zone cooling loads for radiant systems are different from cooling loads for traditional air systems. Energy simulations, in EnergyPlus, and laboratory experiments were conducted to investigate the heat transfer dynamics in spaces conditioned by radiant and air systems. The results show that the magnitude of the cooling load difference between the two systems ranges from 7-85%, and radiant systems remove heat faster than air systems. For the experimental tested conditions, 75-82% of total heat gain was removed by radiant system during the period when the heater (simulating the heat gain) was on, while for air system, 61-63% were removed. From a heat transfer perspective, the differences are mainly because the chilled surfaces directly remove part of the radiant heat gains from a zone, thereby bypassing the time-delay effect caused by the interaction of radiant heat gain with non-active thermal mass in air systems. The major conclusions based on these findings are: 1) there are important limitations in the definition of cooling load for a mixing air system described in Chapter 18 of ASHRAE Handbook of Fundamentals when applied to radiant systems; 2) due to the obvious mismatch between how radiant heat transfer is handled in traditional cooling load calculation methods compared to its central role in radiant cooling systems, this dissertation provides improvements for the current cooling load calculation method based on the Heat Balance procedure. The Radiant Time Series method is not appropriate for radiant system applications. The findings also directly apply to the selection of space heat transfer modeling algorithms that are part of all energy modeling software. Cooling capacity estimation is another critical step in a design project. The above mentioned findings and a review of the existing methods indicates that current radiant system cooling capacity estimation methods fail to take into account incident shortwave radiation generated by solar and lighting in the calculation process. This causes a significant underestimation (up to 150% for some instances) of floor cooling capacity when solar load is dominant. Building performance simulations were conducted to verify this hypothesis and quantify the impacts of solar for different design scenarios. A new simplified method was proposed to improve the predictability of the method described in ISO 11855 when solar radiation is present. The dissertation also compares the energy and comfort benefits of the model-based predictive control (MPC) method with a fine-tuned heuristic control method when applied to a heavyweight embedded surface system. A first order dynamic model of a radiant slab system was developed for implementation in model predictive controllers. A calibrated EnergyPlus model of a typical office building in California was used as a testbed for the comparison. The results indicated that MPC is able to reduce the cooling tower energy consumption by 55% and pumping power consumption by 26%, while maintaining equivalent or even better thermal comfort conditions. In summary, the dissertation work has: (1) provided clear evidence that the fundamental heat transfer mechanisms differ between radiant and air systems. These findings have important implications for the development of accurate and reliable design and energy simulation tools; (2) developed practical design methods and guidance to aid practicing engineers who are designing radiant systems; and (3) outlined future research and design tools need to advance the state-of-knowledge and design and operating guidelines for radiant systems.

Energy saving potential of a two-pipe system for simultaneous heating and cooling of office buildings

DOE PAGES

Maccarini, Alessandro; Wetter, Michael; Afshari, Alireza; ...

2016-10-31

This paper analyzes the performance of a novel two-pipe system that operates one water loop to simultaneously provide space heating and cooling with a water supply temperature of around 22 °C. To analyze the energy performance of the system, a simulation-based research was conducted. The two-pipe system was modelled using the equation-based Modelica modeling language in Dymola. A typical office building model was considered as the case study. Simulations were run for two construction sets of the building envelope and two conditions related to inter-zone air flows. To calculate energy savings, a conventional four-pipe system was modelled and used formore » comparison. The conventional system presented two separated water loops for heating and cooling with supply temperatures of 45 °C and 14 °C, respectively. Simulation results showed that the two-pipe system was able to use less energy than the four-pipe system thanks to three effects: useful heat transfer from warm to cold zones, higher free cooling potential and higher efficiency of the heat pump. In particular, the two-pipe system used approximately between 12% and 18% less total annual primary energy than the four-pipe system, depending on the simulation case considered.« less

Energy saving potential of a two-pipe system for simultaneous heating and cooling of office buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maccarini, Alessandro; Wetter, Michael; Afshari, Alireza

This paper analyzes the performance of a novel two-pipe system that operates one water loop to simultaneously provide space heating and cooling with a water supply temperature of around 22 °C. To analyze the energy performance of the system, a simulation-based research was conducted. The two-pipe system was modelled using the equation-based Modelica modeling language in Dymola. A typical office building model was considered as the case study. Simulations were run for two construction sets of the building envelope and two conditions related to inter-zone air flows. To calculate energy savings, a conventional four-pipe system was modelled and used formore » comparison. The conventional system presented two separated water loops for heating and cooling with supply temperatures of 45 °C and 14 °C, respectively. Simulation results showed that the two-pipe system was able to use less energy than the four-pipe system thanks to three effects: useful heat transfer from warm to cold zones, higher free cooling potential and higher efficiency of the heat pump. In particular, the two-pipe system used approximately between 12% and 18% less total annual primary energy than the four-pipe system, depending on the simulation case considered.« less

Spatiotemporal modeling of node temperatures in supercomputers

DOE PAGES

Storlie, Curtis Byron; Reich, Brian James; Rust, William Newton; ...

2016-06-10

Los Alamos National Laboratory (LANL) is home to many large supercomputing clusters. These clusters require an enormous amount of power (~500-2000 kW each), and most of this energy is converted into heat. Thus, cooling the components of the supercomputer becomes a critical and expensive endeavor. Recently a project was initiated to investigate the effect that changes to the cooling system in a machine room had on three large machines that were housed there. Coupled with this goal was the aim to develop a general good-practice for characterizing the effect of cooling changes and monitoring machine node temperatures in this andmore » other machine rooms. This paper focuses on the statistical approach used to quantify the effect that several cooling changes to the room had on the temperatures of the individual nodes of the computers. The largest cluster in the room has 1,600 nodes that run a variety of jobs during general use. Since extremes temperatures are important, a Normal distribution plus generalized Pareto distribution for the upper tail is used to model the marginal distribution, along with a Gaussian process copula to account for spatio-temporal dependence. A Gaussian Markov random field (GMRF) model is used to model the spatial effects on the node temperatures as the cooling changes take place. This model is then used to assess the condition of the node temperatures after each change to the room. The analysis approach was used to uncover the cause of a problematic episode of overheating nodes on one of the supercomputing clusters. Lastly, this same approach can easily be applied to monitor and investigate cooling systems at other data centers, as well.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chainer, Timothy J.; Parida, Pritish R.

Systems and methods for cooling include one or more computing structure, an inter-structure liquid cooling system that includes valves configured to selectively provide liquid coolant to the one or more computing structures; a heat rejection system that includes one or more heat rejection units configured to cool liquid coolant; and one or more liquid-to-liquid heat exchangers that include valves configured to selectively transfer heat from liquid coolant in the inter-structure liquid cooling system to liquid coolant in the heat rejection system. Each computing structure further includes one or more liquid-cooled servers; and an intra-structure liquid cooling system that has valvesmore » configured to selectively provide liquid coolant to the one or more liquid-cooled servers.« less

An Active Broad Area Cooling Model of a Cryogenic Propellant Tank with a Single Stage Reverse Turbo-Brayton Cycle Cryocooler

NASA Technical Reports Server (NTRS)

Guzik, Monica C.; Tomsik, Thomas M.

2011-01-01

As focus shifts towards long-duration space exploration missions, an increased interest in active thermal control of cryogenic propellants to achieve zero boil-off of cryogens has emerged. An active thermal control concept of considerable merit is the integration of a broad area cooling system for a cryogenic propellant tank with a combined cryocooler and circulator system that can be used to reduce or even eliminate liquid cryogen boil-off. One prospective cryocooler and circulator combination is the reverse turbo-Brayton cycle cryocooler. This system is unique in that it has the ability to both cool and circulate the coolant gas efficiently in the same loop as the broad area cooling lines, allowing for a single cooling gas loop, with the primary heat rejection occurring by way of a radiator and/or aftercooler. Currently few modeling tools exist that can size and characterize an integrated reverse turbo-Brayton cycle cryocooler in combination with a broad area cooling design. This paper addresses efforts to create such a tool to assist in gaining a broader understanding of these systems, and investigate their performance in potential space missions. The model uses conventional engineering and thermodynamic relationships to predict the preliminary design parameters, including input power requirements, pressure drops, flow rate, cycle performance, cooling lift, broad area cooler line sizing, and component operating temperatures and pressures given the cooling load operating temperature, heat rejection temperature, compressor inlet pressure, compressor rotational speed, and cryogenic tank geometry. In addition, the model allows for the preliminary design analysis of the broad area cooling tubing, to determine the effect of tube sizing on the reverse turbo-Brayton cycle system performance. At the time this paper was written, the model was verified to match existing theoretical documentation within a reasonable margin. While further experimental data is needed for full validation, this tool has already made significant steps towards giving a clearer understanding of the performance of a reverse turbo-Brayton cycle cryocooler integrated with broad area cooling technology for zero boil-off active thermal control.

Utilization of municipal wastewater for cooling in thermoelectric power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Safari, Iman; Walker, Michael E.; Hsieh, Ming-Kai

2013-09-01

A process simulation model has been developed using Aspen Plus® with the OLI (OLI System, Inc.) water chemistry model to predict water quality in the recirculating cooling loop utilizing secondary- and tertiary-treated municipal wastewater as the source of makeup water. Simulation results were compared with pilot-scale experimental data on makeup water alkalinity, loop pH, and ammonia evaporation. The effects of various parameters including makeup water quality, salt formation, NH 3 and CO 2 evaporation mass transfer coefficients, heat load, and operating temperatures were investigated. The results indicate that, although the simulation model can capture the general trends in the loopmore » pH, experimental data on the rates of salt precipitation in the system are needed for more accurate prediction of the loop pH. It was also found that stripping of ammonia and carbon dioxide in the cooling tower can influence the cooling loop pH significantly. The effects of the NH 3 mass transfer coefficient on cooling loop pH appear to be more significant at lower values (e.g., k NH3 < 4×10 -3 m/s) when the makeup water alkalinity is low (e.g., <90 mg/L as CaCO 3). The effect of the CO2 mass transfer coefficient was found to be significant only at lower alkalinity values (e.g., k CO2<4×10 -6 m/s).« less

Performance of the dark energy camera liquid nitrogen cooling system

NASA Astrophysics Data System (ADS)

Cease, H.; Alvarez, M.; Alvarez, R.; Bonati, M.; Derylo, G.; Estrada, J.; Flaugher, B.; Flores, R.; Lathrop, A.; Munoz, F.; Schmidt, R.; Schmitt, R. L.; Schultz, K.; Kuhlmann, S.; Zhao, A.

2014-01-01

The Dark Energy Camera, the Imager and its cooling system was installed onto the Blanco 4m telescope at the Cerro Tololo Inter-American Observatory in Chile in September 2012. The imager cooling system is a LN2 two-phase closed loop cryogenic cooling system. The cryogenic circulation processing is located off the telescope. Liquid nitrogen vacuum jacketed transfer lines are run up the outside of the telescope truss tubes to the imager inside the prime focus cage. The design of the cooling system along with commissioning experiences and initial cooling system performance is described. The LN2 cooling system with the DES imager was initially operated at Fermilab for testing, then shipped and tested in the Blanco Coudé room. Now the imager is operating inside the prime focus cage. It is shown that the cooling performance sufficiently cools the imager in a closed loop mode, which can operate for extended time periods without maintenance or LN2 fills.

Hot zone design for controlled growth to mitigate cracking in laser crystal growth

NASA Astrophysics Data System (ADS)

Zhang, Hui; Zheng, Lili; Fang, Haisheng

2011-03-01

Cracking is a major problem during large diameter crystal growth. The objective of this work is to design an effective hot zone for a controlled growth of Yb:S-FAP [Yb3+:Sr5(PO4)3F] laser crystal by the Czochralski technology and effective cooling that can reduce stress. Theoretical and numerical analyses are performed to study the causes of cracking, mitigate the major cracking, as well as reduce cooling time. In the current system, three locations in the crystal are prone to crack, such as the top shoulder of the crystal, the middle portion above the crucible edge, and the bottom tail portion. Based on numerical simulations, we propose a new hot zone design and cooling procedure to grow and cool large diameter crystal without cracking.

Cooling optically levitated dielectric nanoparticles via parametric feedback

NASA Astrophysics Data System (ADS)

Neukirch, Levi; Rodenburg, Brandon; Bhattacharya, Mishkatul; Vamivakas, Nick

2015-05-01

The inability to leverage resonant scattering processes involving internal degrees of freedom differentiates optical cooling experiments performed with levitated dielectric nanoparticles, from similar atomic and molecular traps. Trapping in optical cavities or the application of active feedback techniques have proven to be effective ways to circumvent this limitation. We present our nanoparticle optical cooling apparatus, which is based on parametric feedback modulation of a single-beam gradient force optical trap. This scheme allows us to achieve effective center-of-mass temperatures well below 1 kelvin for our ~ 1 ×10-18 kg particles, at modest vacuum pressures. The method provides a versatile platform, with parameter tunability not found in conventional tethered nanomechanical systems. Potential applications include investigations of nonequilibrium nanoscale thermodynamics, ultra-sensitive force metrology, and mesoscale quantum mechanics and hybrid systems. Supported by the office of Naval Research award number N000141410442.

Increasing the Efficiency of a Thermoelectric Generator Using an Evaporative Cooling System

NASA Astrophysics Data System (ADS)

Boonyasri, M.; Jamradloedluk, J.; Lertsatitthanakorn, C.; Therdyothin, A.; Soponronnarit, S.

2017-05-01

A system for reducing heat from the cold side of a thermoelectric (TE) power generator, based on the principle of evaporative cooling, is presented. An evaporative cooling system could increase the conversion efficiency of a TE generator. To this end, two sets of TE generators were constructed. Both TE generators were composed of five TE power modules. The cold and hot sides of the TE modules were fixed to rectangular fin heat sinks. The hot side heat sinks were inserted in a hot gas duct. The cold side of one set was cooled by the cooling air from a counter flow evaporative cooling system, whereas the other set was cooled by the parallel flow evaporative cooling system. The counter flow pattern had better performance than the parallel flow pattern. A comparison between the TE generator with and without an evaporative cooling system was made. Experimental results show that the power output increased by using the evaporative cooling system. This can significantly increase the TE conversion efficiency. The evaporative cooling system increased the power output of the TE generator from 22.9 W of ambient air flowing through the heat sinks to 28.6 W at the hot gas temperature of 350°C (an increase of about 24.8%). The present study shows the promising potential of using TE generators with evaporative cooling for waste heat recovery.

Radiation Pressure Cooling as a Quantum Dynamical Process

NASA Astrophysics Data System (ADS)

He, Bing; Yang, Liu; Lin, Qing; Xiao, Min

2017-06-01

One of the most fundamental problems in optomechanical cooling is how small the thermal phonon number of a mechanical oscillator can be achieved under the radiation pressure of a proper cavity field. Different from previous theoretical predictions, which were based on an optomechanical system's time-independent steady states, we treat such cooling as a dynamical process of driving the mechanical oscillator from its initial thermal state, due to its thermal equilibrium with the environment, to a stabilized quantum state of higher purity. We find that the stabilized thermal phonon number left in the end actually depends on how fast the cooling process could be. The cooling speed is decided by an effective optomechanical coupling intensity, which constitutes an essential parameter for cooling, in addition to the sideband resolution parameter that has been considered in other theoretical studies. The limiting thermal phonon number that any cooling process cannot surpass exhibits a discontinuous jump across a certain value of the parameter.

Cooling rates and intensity limitations for laser-cooled ions at relativistic energies

NASA Astrophysics Data System (ADS)

Eidam, Lewin; Boine-Frankenheim, Oliver; Winters, Danyal

2018-04-01

The ability of laser cooling for relativistic ion beams is investigated. For this purpose, the excitation of relativistic ions with a continuous wave and a pulsed laser is analyzed, utilizing the optical Bloch equations. The laser cooling force is derived in detail and its scaling with the relativistic factor γ is discussed. The cooling processes with a continuous wave and a pulsed laser system are investigated. Optimized cooling scenarios and times are obtained in order to determine the required properties of the laser and the ion beam for the planed experiments. The impact of beam intensity effects, like intrabeam scattering and space charge are analyzed. Predictions from simplified models are compared to particle-in-cell simulations and are found to be in good agreement. Finally two realistic example cases of Carbon ions in the ESR and relativistic Titanium ions in SIS100 are compared in order to discuss prospects for future laser cooling experiments.

Squeezed cooling of mechanical motion beyond the resolved-sideband limit

NASA Astrophysics Data System (ADS)

Yang, Cheng; Zhang, Lin; Zhang, Weiping

2018-04-01

Cavity optomechanics provides a unique platform for controlling micromechanical systems by means of optical fields that cross the classical-quantum boundary to achieve solid foundations for quantum technologies. Currently, optomechanical resonators have become promising candidates for the development of precisely controlled nano-motors, ultrasensitive sensors and robust quantum information processors. For all these applications, a crucial requirement is to cool the mechanical resonators down to their quantum ground states. In this paper, we present a novel cooling scheme to further cool a micromechanical resonator via the noise squeezing effect. One quadrature in such a resonator can be squeezed to induce enhanced fluctuations in the other, “heated” quadrature, which can then be used to cool the mechanical motion via conventional optomechanical coupling. Our theoretical analysis and numerical calculations demonstrate that this squeeze-and-cool mechanism offers a quick technique for deeply cooling a macroscopic mechanical resonator to an unprecedented temperature region below the zero-point fluctuations.

Environmental Assessment of 2005 Base Realignment and Closure Actions at Homestead Air Reserve Base, Florida

DTIC Science & Technology

2007-02-01

permit, there are no guidelines for storm water quality , therefore Homestead ARB established a program with the State of Florida to test and monitor... storm water quality . Heating and Cooling Systems. Because of the humid Florida climate, engineers are considering an installation-wide Utility... storm water quality , negligible effects on the storm water system would be expected as a result of the Proposed Action. Heating and Cooling

Cooling of Electric Motors Used for Propulsion on SCEPTOR

NASA Technical Reports Server (NTRS)

Christie, Robert J.; Dubois, Arthur; Derlaga, Joseph M.

2017-01-01

NASA is developing a suite of hybrid-electric propulsion technologies for aircraft. These technologies have the benefit of lower emissions, diminished noise, increased efficiency, and reduced fuel burn. These will provide lower operating costs for aircraft operators. Replacing internal combustion engines with distributed electric propulsion is a keystone of this technology suite, but presents many new problems to aircraft system designers. One of the problems is how to cool these electric motors without adding significant aerodynamic drag, cooling system weight or fan power. This paper discusses the options evaluated for cooling the motors on SCEPTOR (Scalable Convergent Electric Propulsion Technology and Operations Research): a project that will demonstrate Distributed Electric Propulsion technology in flight. Options for external and internal cooling, inlet and exhaust locations, ducting and adjustable cowling, and axial and centrifugal fans were evaluated. The final design was based on a trade between effectiveness, simplicity, robustness, mass and performance over a range of ground and flight operation environments.

Secondary fuel delivery system

DOEpatents

Parker, David M.; Cai, Weidong; Garan, Daniel W.; Harris, Arthur J.

2010-02-23

A secondary fuel delivery system for delivering a secondary stream of fuel and/or diluent to a secondary combustion zone located in the transition piece of a combustion engine, downstream of the engine primary combustion region is disclosed. The system includes a manifold formed integral to, and surrounding a portion of, the transition piece, a manifold inlet port, and a collection of injection nozzles. A flowsleeve augments fuel/diluent flow velocity and improves the system cooling effectiveness. Passive cooling elements, including effusion cooling holes located within the transition boundary and thermal-stress-dissipating gaps that resist thermal stress accumulation, provide supplemental heat dissipation in key areas. The system delivers a secondary fuel/diluent mixture to a secondary combustion zone located along the length of the transition piece, while reducing the impact of elevated vibration levels found within the transition piece and avoiding the heat dissipation difficulties often associated with traditional vibration reduction methods.

An Experimental and Numerical Investigation of Endwall Aerodynamics and Heat Transfer in a Gas Turbine Nozzle Guide Vane with Slot Film Cooling

NASA Astrophysics Data System (ADS)

Alqefl, Mahmood Hasan

In many regions of the high-pressure gas turbine, film cooling flows are used to protect the turbine components from the combustor exit hot gases. Endwalls are challenging to cool because of the complex system of secondary flows that disturb surface film coolant coverage. The secondary flow vortices wash the film coolant from the surface into the mainstream significantly decreasing cooling effectiveness. In addition to being effected by secondary flow structures, film cooling flow can also affect these structures by virtue of their momentum exchange. In addition, many studies in the literature have shown that endwall contouring affects the strength of passage secondary flows. Therefore, to develop better endwall cooling schemes, a good understanding of passage aerodynamics and heat transfer as affected by interactions of film cooling flows with secondary flows is required. This experimental and computational study presents results from a linear, stationary, two-passage cascade representing the first stage nozzle guide vane of a high-pressure gas turbine with an axisymmetrically contoured endwall. The sources of film cooling flows are upstream combustor liner coolant and endwall slot film coolant injected immediately upstream of the cascade passage inlet. The operating conditions simulate combustor exit flow features, with a high Reynolds number of 390,000 and approach flow turbulence intensity of 11% with an integral length scale of 21% of the chord length. Measurements are performed with varying slot film cooling mass flow to mainstream flow rate ratios (MFR). Aerodynamic effects are documented with five-hole probe measurements at the exit plane. Heat transfer is documented through recovery temperature measurements with a thermocouple. General secondary flow features are observed. Total pressure loss measurements show that varying the slot film cooling MFR has some effects on passage loss. Velocity vectors and vorticity distributions show a very thin, yet intense, cross-pitch flow on the contoured endwall side. Endwall adiabatic effectiveness values and coolant distribution thermal fields show minimal effects of varying slot film coolant MFR. This suggests the dominant effects of combustor liner coolant. show dominant effects of combustor liner coolant on cooling the endwall. A coolant vorticity correlation presenting the advective mixing of the coolant due to secondary flow vorticity at the exit plane is also discussed.

Optimizing Performance of a Thermal Energy Storage System

NASA Astrophysics Data System (ADS)

Subirats Soler, Monica

In this thesis, the problem of electricity demand shifting for the cooling needs of a large institution using a thermal energy storage (TES) tank is considered. The system is formed by electric chillers, cooling towers and a TES tank that can store energy for the cooling demand of most days, but not for the hottest ones. The goal is to supply all the cooling needed while minimizing the cost. This is done by shifting the cooling demand to night and early morning hours, when electricity is cheaper and due to lower temperatures, the chillers work more efficiently. This is all done with the help of the TES tank, that acts as a buffer storing chilled water. After a series of assumptions and simplifications, the cost function becomes convex and thus a minimum solution exists. However, from previous work only the chillers were considered, omitting the negative effect that other components of the system, such as cooling towers, had on the overall cost of operation. Using data from the operation of the power plant under real conditions, a method to model the whole system is presented in this thesis. In addition, the algorithm relied on the knowledge of an accurate prediction of the cooling demand, which obviously is not known in advance. A method to predict it starting from a forecasting of the temperature is presented. Finally, the algorithm can be easily modified to allow the imposition constraints that limit the maximum power use of chillers, during specific periods, in response to the overall needs of the micro-grid.

Conceptual Study on Hypersonic Turbojet Experimental Vehicle (HYTEX)

NASA Astrophysics Data System (ADS)

Taguchi, Hideyuki; Murakami, Akira; Sato, Tetsuya; Tsuchiya, Takeshi

Pre-cooled turbojet engines have been investigated aiming at realization of reusable space transportation systems and hypersonic airplanes. Evaluation methods of these engine performances have been established based on ground tests. There are some plans on the demonstration of hypersonic propulsion systems. JAXA focused on hypersonic propulsion systems as a key technology of hypersonic transport airplane. Demonstrations of Mach 5 class hypersonic technologies are stated as a development target at 2025 in the long term vision. In this study, systems analyses of hypersonic turbojet experiment (HYTEX) with Mach 5 flight capability is performed. Aerodynamic coefficients are obtained by CFD analyses and wind tunnel tests. Small Pre-cooled turbojet is fabricated and tested using liquid hydrogen as fuel. As a result, characteristics of the baseline vehicle shape is clarified, . and effects of pre-cooling are confirmed at the firing test.

Technical Note: System for evaluating local hypothermia as a radioprotector of the rectum in a small animal model.

PubMed

Hrycushko, Brian A; Bing, Chenchen; Futch, Cecil; Wodzak, Michelle; Stojadinovic, Strahinja; Medin, Paul M; Chopra, Rajiv

2017-08-01

The protective effects of induced or even accidental hypothermia on the human body are widespread with several medical uses currently under active research. In vitro experiments using human cell lines have shown hypothermia provides a radioprotective effect that becomes more pronounced at large, single-fraction doses common to stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS) treatments. This work describes the development of a system to evaluate local hypothermia for a radioprotective effect of the rat rectum during a large dose of radiation relevant to prostate SBRT. This includes the evaluation of a 3D-printed small animal rectal cooling device and the integration with a small animal irradiator. A 3-cm long, dual-lumen rectal temperature control apparatus (RTCA) was designed in SOLIDWORKS CAD for 3D printing. The RTCA was capable of recirculating flow in a device small enough for insertion into the rat rectum, with a metal support rod for strength as well as visibility during radiation treatment planning. The outer walls of the RTCA comprised of thin heat shrink plastic, achieving efficient heat transfer into adjacent tissues. Following leak-proof testing, fiber optic temperature probes were used to evaluate the temperature over time when placed adjacent to the cooling device within the rat rectum. MRI thermometry characterized the relative temperature distribution in concentric ROIs surrounding the probe. Integration with an image-guided small animal irradiator and associated treatment planning system included evaluation for imaging artifacts and effect of brass tubing on dose calculation. The rectal temperature adjacent to the cooling device decreased from body temperature to 15°C within 10-20 min from device insertion and was maintained at 15 ± 3°C during active cooling for the evaluated time of one hour. MR thermometry revealed a steep temperature gradient with increasing distance from the cooling device with the desired temperature range maintained within the surrounding few millimeters. A 3D-printed rectal cooling device was fabricated for the purpose of inducing local hypothermia in the rat rectum. The RTCA was simply integrated with an image-guided small animal irradiator and Monte Carlo-based treatment planning system to facilitate an in vivo investigation of the radioprotective effect of hypothermia for late rectal toxicity following a single large dose of radiation. © 2017 American Association of Physicists in Medicine.

Analysis of hybrid interface cooling system using air ventilation and nanofluid

NASA Astrophysics Data System (ADS)

Rani, M. F. H.; Razlan, Z. M.; Bakar, S. A.; Desa, H.; Wan, W. K.; Ibrahim, I.; Kamarrudin, N. S.; Bin-Abdun, Nazih A.

2017-09-01

The hybrid interface cooling system needs to be designed for maintaining the electric vehicle's battery cell temperature at 25°C. The hybrid interface cooling system is a combination of two individual systems, where the primary cooling system (R-134a) and the secondary cooling system (CuO + Water) will be used to absorb the heat generated by the battery cells. The ventilation system is designed using air as the medium to transfer the heat from the batteries to the refrigeration system (R-134a). Research will focus on determining the suitable compressor displacement, the heat exchanger volume and the expansion valve resistance value. The analysis for the secondary cooling system is focused on the cooling coil where low temperature nanofluid is passing through each interval of the battery cells. For analysing purposes, the thermal properties of the mixture of 50 grams, Copper (II) Oxide and the base fluid have been determined. The hybrid interface cooling system are able to achieve 57.82% increments in term of rate of heat transfer as compared to the individual refrigeration system.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XXV, I--CATERPILLAR DIESEL ENGINE COOLING SYSTEM D-8 AND 824 MODELS, II--TIRES AND TIRE HARDWARE.

ERIC Educational Resources Information Center

Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF THE DIESEL ENGINE COOLING SYSTEM AND TO PROVIDE A DESCRIPTION OF HEAVY TIRES AND WHEELS USED ON DIESEL POWERED VEHICLES. TOPICS ARE (1) THEORY OF THE COOLING SYSTEM, (2) COOLING SYSTEM COMPONENTS, (3) MAINTENANCE TIPS (COOLING SYSTEM), (4)…

Ice Thermal Storage Systems for LWR Supplemental Cooling and Peak Power Shifting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haihua Zhao; Hongbin Zhang; Phil Sharpe

2010-06-01

Availability of enough cooling water has been one of the major issues for the nuclear power plant site selection. Cooling water issues have frequently disrupted the normal operation at some nuclear power plants during heat waves and long draught. The issues become more severe due to the new round of nuclear power expansion and global warming. During hot summer days, cooling water leaving a power plant may become too hot to threaten aquatic life so that environmental regulations may force the plant to reduce power output or even temporarily to be shutdown. For new nuclear power plants to be builtmore » at areas without enough cooling water, dry cooling can be used to remove waste heat directly into the atmosphere. However, dry cooling will result in much lower thermal efficiency when the weather is hot. One potential solution for the above mentioned issues is to use ice thermal storage systems (ITS) that reduce cooling water requirements and boost the plant’s thermal efficiency in hot hours. ITS uses cheap off-peak electricity to make ice and uses those ice for supplemental cooling during peak demand time. ITS is suitable for supplemental cooling storage due to its very high energy storage density. ITS also provides a way to shift large amount of electricity from off peak time to peak time. Some gas turbine plants already use ITS to increase thermal efficiency during peak hours in summer. ITSs have also been widely used for building cooling to save energy cost. Among three cooling methods for LWR applications: once-through, wet cooling tower, and dry cooling tower, once-through cooling plants near a large water body like an ocean or a large lake and wet cooling plants can maintain the designed turbine backpressure (or condensation temperature) during 99% of the time; therefore, adding ITS to those plants will not generate large benefits. For once-through cooling plants near a limited water body like a river or a small lake, adding ITS can bring significant economic benefits and avoid forced derating and shutdown during extremely hot weather. For the new plants using dry cooling towers, adding the ice thermal storage systems can effectively reduce the efficiency loss and water consumption during hot weather so that new LWRs could be considered in regions without enough cooling water. \\ This paper presents the feasibility study of using ice thermal storage systems for LWR supplemental cooling and peak power shifting. LWR cooling issues and ITS application status will be reviewed. Two ITS application case studies will be presented and compared with alternative options: one for once-through cooling without enough cooling for short time, and the other with dry cooling. Because capital cost, especially the ice storage structure/building cost, is the major cost for ITS, two different cost estimation models are developed: one based on scaling method, and the other based on a preliminary design using Building Information Modeling (BIM), an emerging technology in Architecture/Engineering/Construction, which enables design options, performance analysis and cost estimating in the early design stage.« less

Phase Diagram of an Ethylene Glycol-Hexamethylphosphorotriamide System

NASA Astrophysics Data System (ADS)

Solonina, I. A.; Rodnikova, M. N.; Kiselev, M. R.; Khoroshilov, A. V.

2018-02-01

The phase diagram of an ethylene glycol (EG)-hexamethylphosphorotriamide (HMPT) system is studied over two wide temperature intervals (+25°C…-90°C…+40°C) and (-150°C…+40°C) by means of differential scanning calorimetry using INTERTECH DSC Q100 and METTLER TA4000 DSC instruments (Switzerland) in the DSC30 mode with variable cooling/heating rates. Substantial overcooling of the liquid phase, a glass transition, and different types of interaction are observed in the system. No thermal effects are observed in intermediate range of concentrations during the slow cooling/heating processes, and the system remains liquid until the glass transition. The presence of such a metastable phase is attributed to a sharp rise in the viscosity of the system due to different kinds of interaction between the components. HMPT: 2EG and HMPT: EG compounds with crystallization temperatures of +5 and -0.5°C, respectively, are observed upon rapid cooling and slow heating. Changes in enthalpy are calculated for all of the observed thermal effects. The distinction from the phase diagram of H2O-HMFT (literary data) is explained by the difference in the interactions between system components and by the structural differences between EG and H2O.

Design of thermal protection system for 8 foot HTST combustor

NASA Technical Reports Server (NTRS)

Moskowitz, S.

1973-01-01

The combustor in the 8-foot high temperature structures tunnel at the NASA-Langley Research Center has encountered cracking over a period of 50-250 tunnel tests within a limited range of the required operating envelope. A program was conducted which analyzed the failed combustor liner hardware and determined that the mechanism of failure was vibratory fatigue. A vibration damper system using wave springs located axially between the liner T-bar and the liner support was designed as an intermediate solution to extend the life of the current two-pass regenerative air-cooled liner. The effects of liner wall thickness, cooling air passage height, stiffener ring geometry, reflective coatings, and liner material selection were investigated for these designs. Preliminary layout design arrangements including the external water-cooling system requirements, weight estimates, installation requirements and preliminary estimates of manufacturing costs were prepared for the most promissing configurations. A state-of-the-art review of thermal barrier coatings and an evaluation of reflective coatings for the gasside surface of air-cooled liners are included.

Measurements of the effects of thermal contact resistance on steady state heat transfer in phosphoric-acid fuel cell stack

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Alkasab, Kalil A.

1991-01-01

The influence of the thermal contact resistance on the heat transfer between the electrode plates, and the cooling system plate in a phosphoric-acid fuel-cell stack was experimentally investigated. The investigation was conducted using a set-up that simulates the operating conditions prevailing in a phosphoric acid fuel-cell stack. The fuel-cell cooling system utilized three types of coolants, water, engine oil, and air, to remove excess heat generated in the cell electrode and to maintain a reasonably uniform temperature distribution in the electrode plate. The thermal contact resistance was measured as a function of pressure at the interface between the electrode plate and the cooling system plate. The interface pressure range was from 0 kPa to 3448 kPa, while the Reynolds number for the cooling limits varied from 15 to 79 for oil, 1165 to 6165 for water, and 700 to 6864 for air. Results showed that increasing the interface pressure resulted in a higher heat transfer coefficient.

Energy transfer simulation for radiantly heated and cooled enclosures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapman, K.S.; Zhang, P.

1996-11-01

This paper presents the development of a three-dimensional mathematical model to compute heat transfer within a radiantly heated or cooled room, which then calculates the mass-averaged room air temperature and the wall surface temperature distributions. The radiation formulation used in the model accommodates arbitrary placement of walls and objects within the room. The convection model utilizes Nusselt number correlations published in the open literature. The complete energy transfer model is validated by comparing calculated room temperatures to temperatures measured in a radiantly heated room. This three-dimensional model may be applied to a building to assist the heating/cooling system design engineermore » in sizing a radiant heating/cooling system. By coupling this model with a thermal comfort model, the comfort levels throughout the room can be easily and efficiently mapped for a given radiant heater/cooler location. In addition, obstacles such as airplanes, trucks, furniture, and partitions can be easily incorporated to determine their effect on the radiant heating system performance.« less

Turbine airfoil with an internal cooling system having vortex forming turbulators

DOEpatents

Lee, Ching-Pang

2014-12-30

A turbine airfoil usable in a turbine engine and having at least one cooling system is disclosed. At least a portion of the cooling system may include one or more cooling channels having a plurality of turbulators protruding from an inner surface and positioned generally nonorthogonal and nonparallel to a longitudinal axis of the airfoil cooling channel. The configuration of turbulators may create a higher internal convective cooling potential for the blade cooling passage, thereby generating a high rate of internal convective heat transfer and attendant improvement in overall cooling performance. This translates into a reduction in cooling fluid demand and better turbine performance.

Hydronic radiant cooling: Overview and preliminary performance assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feustel, H.E.

1993-05-01

A significant amount of electrical energy used to cool non-residential buildings is drawn by the fans used to transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the building by separating ventilation and thermal conditioning. Due to the physical properties of water, hydronic distribution systems can transport a given amount of thermal energy using less than 5% of the otherwise necessary fan energy. This savings alone significantly reduces the energy consumption and especially the peak power requirement This survey clearly shows advantages for radiant cooling in combination with hydronic thermal distributionmore » systems in comparison with the All-Air Systems commonly used in California. The report describes a literature survey on the system`s development, thermal comfort issues, and cooling performance. The cooling power potential and the cooling power requirement are investigated for several California climates. Peak-power requirement is compared for hydronic radiant cooling and conventional All-Air-Systems.« less

Effects of cooling interval and MnO2, TiO2, CdO, NiO additions on spheluritic willemite crystals

NASA Astrophysics Data System (ADS)

Coşkun, Nihal Derin; Uz, Veli; Issi, Ali; Genç, Soner; Çakı, Münevver

2017-01-01

Macro crystal production in crystal glaze systems is a very important topic in ceramic art and science. In this study, crystal growth was obtained in two different firing regimes. Recipes were prepared by adding MnO, TiO, NiO and CdO into the frit. The first firing regime, which is used in artistic ceramics, has a 100 °C cooling temperature interval. The second regime that has a 580 °C cooling temperature interval, was determined by DTA analysis. Then, the development of crystals was compared between these two firing regimes. According to the results, spheluritic willemite crystals up to three cm in the glazes doped MnO2 have been obtained by cooling it in a wide cooling interval. Larger willemite crystals were not formed in the narrow cooling temperature interval. It was determined that larger crystals can be produced by cooling at wide cooling temperature intervals and holding at lower temperature which involves nucleating the temperature of the crystal.

An Improved X-Band Maser System for Deep Space Network Applications

NASA Astrophysics Data System (ADS)

Britcliffe, M.; Hanson, T.; Fernandez, J.

2000-01-01

An 8450-MHz (X-band) maser system utilizing a commercial Gifford--McMahon (GM) closed-cycle cryocooler (CCR) was designed, fabricated, and demonstrated. The CCR system was used to cool a maser operating at 8450 MHz. The prototype GM CCR system meets or exceeds all Deep Space Network requirements for maser performance. The two-stage GM CCR operates at 4.2 K; for comparison, the DSN's current three-stage cryocooler, which uses a Joule--Thompson cooling stage in addition to GM cooling, operates at 4.5 K. The new CCR withstands heat loads of 1.5 W at 4.2 K as compared to 1 W at 4.5 K for the existing DSN cryocooler used for cooling masers. The measured noise temperature, T_e, of the maser used for these tests is defined at the ambient connection to the antenna feed system. The T_e measured 5.0 K at a CCR temperature of 4.5 K, about 1.5 K higher than the noise temperature of a typical DSN Block II-A X-band traveling-wave maser (TWM). Reducing the temperature of the CCR significantly lowers the maser noise temperature and increases maser gain and bandwidth. The new GM CCR gives future maser systems significant operational advantages, including reduced maintenance time and logistics requirements. The results of a demonstration of this new system are presented. Advantages of using a GM-cooled maser and the effects of the reduced CCR temperature on maser performance are discussed.

Study on heat transfer coefficients during cooling of PET bottles for food beverages

NASA Astrophysics Data System (ADS)

Liga, Antonio; Montesanto, Salvatore; Mannella, Gianluca A.; La Carrubba, Vincenzo; Brucato, Valerio; Cammalleri, Marco

2016-08-01

The heat transfer properties of different cooling systems dealing with Poly-Ethylene-Terephthalate (PET) bottles were investigated. The heat transfer coefficient (Ug) was measured in various fluid dynamic conditions. Cooling media were either air or water. It was shown that heat transfer coefficients are strongly affected by fluid dynamics conditions, and range from 10 W/m2 K to nearly 400 W/m2 K. PET bottle thickness effect on Ug was shown to become relevant under faster fluid dynamics regimes.

Experimental study of high-performance cooling system pipeline diameter and working fluid amount

NASA Astrophysics Data System (ADS)

Nemec, Patrik; Malcho, Milan; Hrabovsky, Peter; Papučík, Štefan

2016-03-01

This work deals with heat transfer resulting from the operation of power electronic components. Heat is removed from the mounting plate, which is the evaporator of the loop thermosyphon to the condenser and by natural convection is transferred to ambient. This work includes proposal of cooling device - loop thermosyphon, with its construct and follow optimization of cooling effect. Optimization proceeds by selecting the quantity of working fluid and selection of diameters vapour line and liquid line of loop thermosyphon.

Investigation of Spray Cooling Schemes for Dynamic Thermal Management

NASA Astrophysics Data System (ADS)

Yata, Vishnu Vardhan Reddy

This study aims to investigate variable flow and intermittent flow spray cooling characteristics for efficiency improvement in active two-phase thermal management systems. Variable flow spray cooling scheme requires control of pump input voltage (or speed), while intermittent flow spray cooling scheme requires control of solenoid valve duty cycle and frequency. Several testing scenarios representing dynamic heat load conditions are implemented to characterize the overall performance of variable flow and intermittent flow spray cooling cases in comparison with the reference, steady flow spray cooling case with constant flowrate, continuous spray cooling. Tests are conducted on a small-scale, closed loop spray cooling system featuring a pressure atomized spray nozzle. HFE-7100 dielectric liquid is selected as the working fluid. Two types of test samples are prepared on 10 mm x 10 mm x 2 mm copper substrates with matching size thick film resistors attached onto the opposite side, to generate heat and simulate high heat flux electronic devices. The test samples include: (i) plain, smooth surface, and (ii) microporous surface featuring 100 ?m thick copper-based coating prepared by dual stage electroplating technique. Experimental conditions involve HFE-7100 at atmospheric pressure and 30°C and 10°C subcooling. Steady flow spray cooling tests are conducted at flow rates of 2-5 ml/cm2.s, by controlling the heat flux in increasing steps, and recording the corresponding steady-state temperatures to obtain cooling curves in the form of surface superheat vs. heat flux. Variable flow and intermittent flow spray cooling tests are done at selected flowrate and subcooling conditions to investigate the effects of dynamic flow conditions on maintaining the target surface temperatures defined based on reference steady flow spray cooling performance.

Preliminary design of an alternate high-temperature turbine. A topical report for Phase II of the High-Temperature-Turbine Technology Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strough, R.I.

The feasibility of designing a convectively air-cooled turbine to operate in the environment of a 3000/sup 0/F combustor exit temperature with maximum turbine airfoil metal temperatures held to 1500/sup 0/F was established. The United Technologies-Kraftwerk Union V84.3 gas turbine design was used as the basic configuration for the design of the 3000/sup 0/F turbine. Turbine cooling requirements were determined based on the use of the modified V84.3 type silo combustor with a pattern factor of 0.1. The convective air-cooling technology levels in terms of cooling effectiveness required to satisfy the airfoil cooling requirements were identified. Cooling schemes and fabrication technologiesmore » required are discussed. Turbine airfoil cooling technology levels required for the 3000/sup 0/F engine were selected. The performance of the 3000/sup 0/F convectively air-cooled gas turbine in simple and combined cycle was calculated. The 3000/sup 0/F gas turbine combined-cycle system provides an increase in power of 61% and a decrease in heat rate of 10% compared to a similar system with a combustor exit temperature of 2210/sup 0/F and the same airflow. The development of a successful 3000/sup 0/F convectively air-cooled turbine can be accomplished with a reasonable design and fabrication development effort on the cooled turbine airfoils. Use of the convectively air-cooled turbine provides the transfer of technology from extensive aircraft engines developed programs and operating experience to industrial gas turbines. It eliminates the requirement for large investments in alternate cooling techniques tailored specifically for industrial engines which offer no additional benefits.« less

Effects of turbine cooling assumptions on performance and sizing of high-speed civil transport

NASA Technical Reports Server (NTRS)

Senick, Paul F.

1992-01-01

The analytical study presented examines the effects of varying turbine cooling assumptions on the performance of a high speed civil transport propulsion system as well as the sizing sensitivity of this aircraft to these performance variations. The propulsion concept employed in this study was a two spool, variable cycle engine with a sea level thrust of 55,000 lbf. The aircraft used for this study was a 250 passenger vehicle with a cruise Mach number of 2.4 and 5000 nautical mile range. The differences in turbine cooling assumptions were represented by varying the amount of high pressure compressor bleed air used to cool the turbines. It was found that as this cooling amount increased, engine size and weight increased, but specific fuel consumption (SFC) decreased at takeoff and climb only. Because most time is spent at cruise, the SFC advantage of the higher bleed engines seen during subsonic flight was minimized and the lower bleed, lighter engines led to the lowest takeoff gross weight vehicles. Finally, the change in aircraft takeoff gross weight versus turbine cooling level is presented.

Stimulatory effect of cooling tower biocides on amoebae.

PubMed

Srikanth, S; Berk, S G

1993-10-01

Two species of amoebae were isolated from the cooling tower of an air-conditioning system and examined for effects of exposure to four cooling tower biocides, a thiocarbamate compound, tributyltin neodecanoate mixed with quaternary ammonium compounds, another quaternary ammonium compound alone, and an isothiazolin derivative. The amoebae isolated were Acanthamoeba hatchetti and a Cochliopodium species. Two other amoeba cultures, an A. hatchetti culture and Cochliopodium bilimbosum, were obtained from the American Type Culture Collection (ATCC) and were also tested. The cooling tower isolates were more resistant to most of the biocides than the ATCC isolates were. The isothiazolin derivative was the least inhibitory to all four amoeba isolates, and tributyltin neodecanoate mixed with quaternary ammonium compounds was the most inhibitory to three of the four isolates. After exposure to lower concentrations of the biocides, including for one strain the manufacturer's recommended concentration of one biocide, the cooling tower amoeba populations increased significantly compared with unexposed controls, whereas the ATCC isolates were not stimulated at any of the concentrations tested. In some cases, concentrations which stimulated cooling tower amoebae inhibited the growth of the ATCC isolates. These results suggest that cooling tower amoebae may adapt to biocides, underscoring the need to use freshly isolated cooling tower organisms rather than organisms from culture collections for testing the efficacy of such biocides. The stimulatory effect of biocides on amoeba populations is an alarming observation, since these organisms may be reservoirs for legionellae. Biocides used to control microbial growth may actually enhance populations of host organisms for pathogenic bacteria.

Cooling Tests of an Airplane Equipped with an NACA Cowling and a Wing-duct Cooling System

NASA Technical Reports Server (NTRS)

Turner, L I , Jr; Bierman, David; Boothy, W B

1941-01-01

Cooling tests were made of a Northrop A-17A attack airplane successively equipped with a conventional.NACA cowling and with a wing-duct cooling system. The method of cooling the engine by admitting air from the propeller slipstream into wing ducts, passing it first through the accessory compartment and then over the engine from rear to front, appeared to offer possibilities for improved engine cooling, increased cooling of the accessories, and better fairing of the power-plant installation. The results showed that ground cooling for the wing duct system without cowl flap was better than for the NACA cowling with flap; ground cooling was appreciably improved by installing a cowl flap. Satisfactory temperatures were maintained in both climb and high-speed flight, but, with the use of conventional baffles, a greater quantity of cooling air appeared to be required for the wing duct system.

Revisiting the Cooling Flow Problem in Galaxies, Groups, and Clusters of Galaxies

NASA Astrophysics Data System (ADS)

McDonald, M.; Gaspari, M.; McNamara, B. R.; Tremblay, G. R.

2018-05-01

We present a study of 107 galaxies, groups, and clusters spanning ∼3 orders of magnitude in mass, ∼5 orders of magnitude in central galaxy star formation rate (SFR), ∼4 orders of magnitude in the classical cooling rate ({\\dot{M}}cool}\\equiv {M}gas}(r< {r}cool})/{t}cool}) of the intracluster medium (ICM), and ∼5 orders of magnitude in the central black hole accretion rate. For each system in this sample, we measure the ICM cooling rate, {\\dot{M}}cool}, using archival Chandra X-ray data and acquire the SFR and systematic uncertainty in the SFR by combining over 330 estimates from dozens of literature sources. With these data, we estimate the efficiency with which the ICM cools and forms stars, finding {ε }cool}\\equiv {SFR}/{\\dot{M}}cool}=1.4 % +/- 0.4% for systems with {\\dot{M}}cool}> 30 M ⊙ yr‑1. For these systems, we measure a slope in the SFR–{\\dot{M}}cool} relation greater than unity, suggesting that the systems with the strongest cool cores are also cooling more efficiently. We propose that this may be related to, on average, higher black hole accretion rates in the strongest cool cores, which could influence the total amount (saturating near the Eddington rate) and dominant mode (mechanical versus radiative) of feedback. For systems with {\\dot{M}}cool}< 30 M ⊙ yr‑1, we find that the SFR and {\\dot{M}}cool} are uncorrelated and show that this is consistent with star formation being fueled at a low (but dominant) level by recycled ISM gas in these systems. We find an intrinsic log-normal scatter in SFR at a fixed {\\dot{M}}cool} of 0.52 ± 0.06 dex (1σ rms), suggesting that cooling is tightly self-regulated over very long timescales but can vary dramatically on short timescales. There is weak evidence that this scatter may be related to the feedback mechanism, with the scatter being minimized (∼0.4 dex) for systems for which the mechanical feedback power is within a factor of two of the cooling luminosity.

Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

None,

1981-09-01

Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

Effect of Propeller on Engine Cooling System Drag and Performance

NASA Technical Reports Server (NTRS)

Katz, Joseph; Corsiglia, Victor R.; Barlow, Philip R.

1982-01-01

The pressure recovery of incoming cooling air and the drag associated with engine cooling of a typical general aviation twin-engine aircraft was Investigated experimentally. The semispan model was mounted vertically in the 40 x 80-Foot Wind Tunnel at Ames Research Center. The propeller was driven by an electric motor to provide thrust with low vibration levels for the cold-now configuration. It was found that the propeller slip-stream reduces the frontal air spillage around the blunt nacelle shape. Consequently, this slip-stream effect promotes flow reattachment at the rear section of the engine nacelle and improves inlet pressure recovery. These effects are most pronounced at high angles of attack; that is, climb condition. For the cruise condition those improvements were more moderate.

Anomalous cooling and heating - the Mpemba effect and its inverse

NASA Astrophysics Data System (ADS)

Lu, Zhiyue; Raz, Oren

Under certain conditions, it takes a shorter time to cool a hot object than to cool the same object initiated at a lower temperature. This counter-intuitive phenomenon - the 'Mpemba Effect'\\x9D, has been observed in a variety of systems. So far, no generic mechanism was suggested to explain this effect. In the theoretical framework of non-equilibrium thermodynamics, we construct a model to describe this effect and illustrates the fundamental principles behind it. In addition, we predict and demonstrate an inverse Mpemba effect: it can take a shorter time to heat a cold object than a warmer one. We derive sufficient conditions for the occurrences of both the forward and the inverse Mpemba effects, and suggest experiments to further study the non-equilibrium nature of these effects. Z.L. acknowledges financial support from the NSF under Grant DMR-1206971. O.R. acknowledges financial support from the James S. McDonnell Foundation.

The seasonal performance of a liquid-desiccant air conditioner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowenstein, A.; Novosel, D.

1995-08-01

Prior reports on liquid-desiccant systems have focused on their steady-state operation at ARI design conditions. By studying their performance during an entire cooling season, the computer modeling presented here shows that liquid-desiccant systems can have a very high seasonal coefficient of performance (COP). For a liquid-desiccant system that uses a double-effect boiler, COPs ranging from 1.44 in a humid location (Houston) to 2.24 in a dry location (Phoenix) are achieved by fully exploiting indirect evaporative cooling and providing only the minimum latent cooling needed to meet the loads on the building. This minimizes the amount of water absorbed by themore » desiccant and, hence, the amount of thermal energy needed to regenerate it. In applications where latent loads are very high, such as processing the high volumes of ventilation air required to maintain good indoor air quality, the liquid-desiccant air conditioner again has an advantage over vapor-compression equipment. In this study, a liquid-desiccant system is modeled that cools and dehumidifies only the ventilation air of an office building in Atlanta. Although processing an airstream that is only 25% of the total air delivered to the building, the liquid-desiccant system is able to meet 52% of the building`s seasonal cooling requirements and reduce the building`s peak electrical demand by about 47%.« less

Thermal management in inertial fusion energy slab amplifiers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutton, S.B.; Albrecht, G.F.

As the technology associated with the development of solid-state drivers for inertial fusion energy (IFE) has evolved, increased emphasis has been placed on the development of an efficient approach for managing the waste heat generated in the laser media. This paper addresses the technical issues associated with the gas cooling of large aperture slabs, where the laser beam propagates through the cooling fluid. It is shown that the major consequence of proper thermal management is the introduction of simple wedge, or beam steering, into the system. Achieving proper thermal management requires careful consideration of the geometry, cooling fluid characteristics, coolingmore » flow characteristics, as well as the thermal/mechanical/optical characteristics of the laser media. Particularly important are the effects of cooling rate variation and turbulent scattering on the system optical performance. Helium is shown to have an overwhelming advantage with respect to turbulent scattering losses. To mitigate cooling rate variations, the authors introduce the concept of flow conditioning. Finally, optical path length variations across the aperture are calculated. A comparison of two laser materials (S-FAP and YAG) shows the benefit of a nearly a-thermal material on optical variations in the system.« less

Use of cooling air heat exchangers as replacements for hot section strategic materials

NASA Technical Reports Server (NTRS)

Gauntner, J. W.

1983-01-01

Because of financial and political constraints, strategic aerospace materials required for the hot section of future engines might be in short supply. As an alternative to these strategic materials, this study examines the use of a cooling air heat exchanger in combination with less advanced hot section materials. Cycle calculations are presented for future turbofan systems with overall pressure ratios to 65, bypass ratios near 13, and combustor exit temperatures to 3260 R. These calculations quantify the effect on TSFC of using a decreased materials technology in a turbofan system. The calculations show that the cooling air heat exchanger enables the feasibility of these engines. Previously announced in STAR as N83-34946

How to control bio-slime in condenser cooling system water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freymark, S.

1979-08-01

A number of oxidizing and non-oxidizing biocides are currently used for biocontrol. However, yesterday's solution to slime-fouling problems may not apply today in view of tightening effluent restrictions on chlorine. Thus, selection of biocontrol compounds can not be made indiscriminately. In selecting alternative biocontrol compounds, consideration should be given not only to costs but to effectiveness of the biocide in each particular application, taking into consideration cooling water quality, type of microbiological fouling and discharge restrictions. Thoughtful selection of the biocontrol compound(s), alone or in combination with surface-active agents, is essential for maintaining maximum microbiological control in condenser cooling watermore » systems.« less

Cooling of a dwelling by nocturnal radiation

NASA Astrophysics Data System (ADS)

Fahim, Othmane; Belouaggadia, Naoual; Taqi, Mohamed; Abid, Chérifa

2018-05-01

Atmospheric transparency in the infrared, responsible for night cooling, is exploited to obtain a cooling effect. Radiative cooling to the night sky is based on the principle of infrared radiation heat loss from a surface to a body at a lower temperature. The use of the emissivity equation allowed us to evaluate its variation as a function of wavelength and temperature. A comparison of the temperature variation was made between granite and the materials most often used in the manufacture of radiant panels of hybrid systems. The results show that the temperature of Tedlar-based plates or plastics considerably decreases, and, therefore are rather promising.

40 CFR 90.307 - Engine cooling system.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine cooling system. 90.307 Section...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Emission Test Equipment Provisions § 90.307 Engine cooling system. An engine cooling system is required with sufficient capacity to...

40 CFR 90.307 - Engine cooling system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine cooling system. 90.307 Section...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Emission Test Equipment Provisions § 90.307 Engine cooling system. An engine cooling system is required with sufficient capacity to...

40 CFR 89.329 - Engine cooling system.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine cooling system. 89.329 Section...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Test Equipment Provisions § 89.329 Engine cooling system. An engine cooling system is required with sufficient capacity to...

40 CFR 91.307 - Engine cooling system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine cooling system. 91.307 Section...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Test Equipment Provisions § 91.307 Engine cooling system. An engine cooling system is required with sufficient capacity to maintain the engine at...

40 CFR 89.329 - Engine cooling system.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine cooling system. 89.329 Section...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Test Equipment Provisions § 89.329 Engine cooling system. An engine cooling system is required with sufficient capacity to...

40 CFR 89.329 - Engine cooling system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine cooling system. 89.329 Section...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Test Equipment Provisions § 89.329 Engine cooling system. An engine cooling system is required with sufficient capacity to...

40 CFR 91.307 - Engine cooling system.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine cooling system. 91.307 Section...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Test Equipment Provisions § 91.307 Engine cooling system. An engine cooling system is required with sufficient capacity to maintain the engine at...

40 CFR 90.307 - Engine cooling system.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine cooling system. 90.307 Section...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Emission Test Equipment Provisions § 90.307 Engine cooling system. An engine cooling system is required with sufficient capacity to...

40 CFR 89.329 - Engine cooling system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine cooling system. 89.329 Section...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Test Equipment Provisions § 89.329 Engine cooling system. An engine cooling system is required with sufficient capacity to...

Neutrino Processes in Neutron Stars

NASA Astrophysics Data System (ADS)

Kolomeitsev, E. E.; Voskresensky, D. N.

2010-10-01

The aim of these lectures is to introduce basic processes responsible for cooling of neutron stars and to show how to calculate the neutrino production rate in dense strongly interacting nuclear medium. The formalism is presented that treats on equal footing one-nucleon and multiple-nucleon processes and reactions with virtual bosonic modes and condensates. We demonstrate that neutrino emission from dense hadronic component in neutron stars is subject of strong modifications due to collective effects in the nuclear matter. With the most important in-medium processes incorporated in the cooling code an overall agreement with available soft X ray data can be easily achieved. With these findings the so-called “standard” and “non-standard” cooling scenarios are replaced by one general “nuclear medium cooling scenario” which relates slow and rapid neutron star coolings to the star masses (interior densities). The lectures are split in four parts. Part I: After short introduction to the neutron star cooling problem we show how to calculate neutrino reaction rates of the most efficient one-nucleon and two-nucleon processes. No medium effects are taken into account in this instance. The effects of a possible nucleon pairing are discussed. We demonstrate that the data on neutron star cooling cannot be described without inclusion of medium effects. It motivates an assumption that masses of the neutron stars are different and that neutrino reaction rates should be strongly density dependent. Part II: We introduce the Green’s function diagram technique for systems in and out of equilibrium and the optical theorem formalism. The latter allows to perform calculations of production rates with full Green’s functions including all off-mass-shell effects. We demonstrate how this formalism works within the quasiparticle approximation. Part III: The basic concepts of the nuclear Fermi liquid approach are introduced. We show how strong interaction effects can be included within the Green’s function formalism. Softening of the pion mode with an baryon density increase is explicitly incorporated. We show examples of inconsistencies in calculations without inclusion of medium effects. Then we demonstrate calculations of different reaction rates in non-superfluid nuclear matter with taking into account medium effects. Many new reaction channels are open up in the medium and should be analyzed. Part IV: We discuss the neutrino production reactions in superfluid nuclear systems. The reaction rates of processes associated with the pair breaking and formation are calculated. Special attention is focused on the gauge invariance and the exact fulfillment of the Ward identities for the vector current. Finally we present comparison of calculations of neutron star cooling performed within nuclear medium cooling scenario with the available data.

A Physiological Systems Approach to Modeling and Resetting of Mouse Thermoregulation under Heat Stress

DTIC Science & Technology

2011-09-01

represent the current treatment strategies, but there are currently no effective phar- macological treatments for HS. Despite clinical cooling thera- pies...and profound encephalopathy that presents as delirium, agitation, stupor, seizures, or coma (6). Rapid cooling therapy and fluid resuscitation...biochemical reactions on temperature is described by the van’t Hoff Q10 effect (24) with a sensitivity coefficient of 2. In addition to blood perfusion rates

Hydronic radiant cooling: Overview and preliminary performance assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feustel, H.E.

1993-05-01

A significant amount of electrical energy used to cool non-residential buildings is drawn by the fans used to transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the building by separating ventilation and thermal conditioning. Due to the physical properties of water, hydronic distribution systems can transport a given amount of thermal energy using less than 5% of the otherwise necessary fan energy. This savings alone significantly reduces the energy consumption and especially the peak power requirement This survey clearly shows advantages for radiant cooling in combination with hydronic thermal distributionmore » systems in comparison with the All-Air Systems commonly used in California. The report describes a literature survey on the system's development, thermal comfort issues, and cooling performance. The cooling power potential and the cooling power requirement are investigated for several California climates. Peak-power requirement is compared for hydronic radiant cooling and conventional All-Air-Systems.« less

Passive cooling safety system for liquid metal cooled nuclear reactors

DOEpatents

Hunsbedt, Anstein; Boardman, Charles E.; Hui, Marvin M.; Berglund, Robert C.

1991-01-01

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of partitions surrounding the reactor vessel in spaced apart relation forming intermediate areas for circulating heat transferring fluid which remove and carry away heat from the reactor vessel. The passive cooling system includes a closed primary fluid circuit through the partitions surrounding the reactor vessel and a partially adjoining secondary open fluid circuit for carrying transferred heat out into the atmosphere.

Indirect passive cooling system for liquid metal cooled nuclear reactors

DOEpatents

Hunsbedt, Anstein; Boardman, Charles E.

1990-01-01

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of partitions surrounding the reactor vessel in spaced apart relation forming intermediate areas for circulating heat transferring fluid which remove and carry away heat from the reactor vessel. The passive cooling system includes a closed primary fluid circuit through the partitions surrounding the reactor vessel and a partially adjoining secondary open fluid circuit for carrying transferred heat out into the atmosphere.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jiachen; Zhang, Kai; Liu, Junfeng

Solar reflective “cool roofs” absorb less sunlight than traditional dark roofs, reducing solar heat gain, and decreasing the amount of heat transferred to the atmosphere. Widespread adoption of cool roofs could therefore reduce temperatures in urban areas, partially mitigating the urban heat island effect, and contributing to reversing the local impacts of global climate change. The impacts of cool roofs on global climate remain debated by past research and are uncertain. Using a sophisticated Earth system model, the impacts of cool roofs on climate are investigated at urban, continental, and global scales. We find that global adoption of cool roofsmore » in urban areas reduces urban heat islands everywhere, with an annual- and global-mean decrease from 1.6 to 1.2 K. Decreases are statistically significant, except for some areas in Africa and Mexico where urban fraction is low, and some high-latitude areas during wintertime. Analysis of the surface and TOA energy budget in urban regions at continental-scale shows cool roofs causing increases in solar radiation leaving the Earth-atmosphere system in most regions around the globe, though the presence of aerosols and clouds are found to partially offset increases in upward radiation. Aerosols dampen cool roof-induced increases in upward solar radiation, ranging from 4% in the United States to 18% in more polluted China. Adoption of cool roofs also causes statistically significant reductions in surface air temperatures in urbanized regions of China (0.11±0.10 K) and the United States (0.14±0.12 K); India and Europe show statistically insignificant changes. The research presented here indicates that adoption of cool roofs around the globe would lead to statistically insignificant reductions in global mean air temperature (0.0021 ±0.026 K). This counters past research suggesting that cool roofs can reduce, or even increase global mean temperatures. Thus, we suggest that while cool roofs are an effective tool for reducing building energy use in hot climates, urban heat islands, and regional air temperatures, their influence on global climate is likely negligible.« less

Cooling Performance Analysis of ThePrimary Cooling System ReactorTRIGA-2000Bandung

NASA Astrophysics Data System (ADS)

Irianto, I. D.; Dibyo, S.; Bakhri, S.; Sunaryo, G. R.

2018-02-01

The conversion of reactor fuel type will affect the heat transfer process resulting from the reactor core to the cooling system. This conversion resulted in changes to the cooling system performance and parameters of operation and design of key components of the reactor coolant system, especially the primary cooling system. The calculation of the operating parameters of the primary cooling system of the reactor TRIGA 2000 Bandung is done using ChemCad Package 6.1.4. The calculation of the operating parameters of the cooling system is based on mass and energy balance in each coolant flow path and unit components. Output calculation is the temperature, pressure and flow rate of the coolant used in the cooling process. The results of a simulation of the performance of the primary cooling system indicate that if the primary cooling system operates with a single pump or coolant mass flow rate of 60 kg/s, it will obtain the reactor inlet and outlet temperature respectively 32.2 °C and 40.2 °C. But if it operates with two pumps with a capacity of 75% or coolant mass flow rate of 90 kg/s, the obtained reactor inlet, and outlet temperature respectively 32.9 °C and 38.2 °C. Both models are qualified as a primary coolant for the primary coolant temperature is still below the permitted limit is 49.0 °C.

Feasibility Study of Venus Surfuce Cooling Using Chemical Reactions with the Atmosphere

NASA Technical Reports Server (NTRS)

Evans, Christopher

2013-01-01

A literature search and theoretical analysis were conducted to investigate the feasibility of cooling a craft on Venus through chemical reformation of materials from the atmosphere. The core concept was to take carbon dioxide (CO2) from the Venus atmosphere and chemically reform it into simpler compounds such as carbon, oxygen, and carbon monoxide. This process is endothermic, taking energy from the surroundings to produce a cooling effect. A literature search was performed to document possible routes for achieving the desired reactions. Analyses indicated that on Venus, this concept could theoretically be used to produce cooling, but would not perform as well as a conventional heat pump. For environments other than Venus, the low theoretical performance limits general applicability of this concept, however this approach to cooling may be useful in niche applications. Analysis indicated that environments with particular atmospheric compositions and temperatures could allow a similar cooling system to operate with very good performance. This approach to cooling may also be useful where the products of reaction are also desirable, or for missions where design simplicity is valued. Conceptual designs for Venus cooling systems were developed using a modified concept, in which an expendable reactant supply would be used to promote more energetically favorable reactions with the ambient CO2, providing cooling for a more limited duration. This approach does not have the same performance issues, but the use of expendable supplies increases the mass requirements and limits the operating lifetime. This paper summarizes the findings of the literature search and corresponding analyses of the various cooling options

Feasibility Study of Venus Surface Cooling Using Chemical Reactions with the Atmosphere

NASA Technical Reports Server (NTRS)

Evans, Christopher

2013-01-01

A literature search and theoretical analysis were conducted to investigate the feasibility of cooling a craft on Venus through chemical reformation of materials from the atmosphere. The core concept was to take carbon dioxide (CO2) from the Venus atmosphere and chemically reform it into simpler compounds such as carbon, oxygen, and carbon monoxide. This process is endothermic, taking energy from the surroundings to produce a cooling effect. A literature search was performed to document possible routes for achieving the desired reactions. Analyses indicated that on Venus, this concept could theoretically be used to produce cooling, but would not perform as well as a conventional heat pump. For environments other than Venus, the low theoretical performance limits general applicability of this concept, however this approach to cooling may be useful in niche applications. Analysis indicated that environments with particular atmospheric compositions and temperatures could allow a similar cooling system to operate with very good performance. This approach to cooling may also be useful where the products of reaction are also desirable, or for missions where design simplicity is valued. Conceptual designs for Venus cooling systems were developed using a modified concept, in which an expendable reactant supply would be used to promote more energetically favorable reactions with the ambient CO2, providing cooling for a more limited duration. This approach does not have the same performance issues, but the use of expendable supplies increases the mass requirements and limits the operating lifetime. This paper summarizes the findings of the literature search and corresponding analyses of the various cooling options.

Integrated computational study of ultra-high heat flux cooling using cryogenic micro-solid nitrogen spray

NASA Astrophysics Data System (ADS)

Ishimoto, Jun; Oh, U.; Tan, Daisuke

2012-10-01

A new type of ultra-high heat flux cooling system using the atomized spray of cryogenic micro-solid nitrogen (SN2) particles produced by a superadiabatic two-fluid nozzle was developed and numerically investigated for application to next generation super computer processor thermal management. The fundamental characteristics of heat transfer and cooling performance of micro-solid nitrogen particulate spray impinging on a heated substrate were numerically investigated and experimentally measured by a new type of integrated computational-experimental technique. The employed Computational Fluid Dynamics (CFD) analysis based on the Euler-Lagrange model is focused on the cryogenic spray behavior of atomized particulate micro-solid nitrogen and also on its ultra-high heat flux cooling characteristics. Based on the numerically predicted performance, a new type of cryogenic spray cooling technique for application to a ultra-high heat power density device was developed. In the present integrated computation, it is clarified that the cryogenic micro-solid spray cooling characteristics are affected by several factors of the heat transfer process of micro-solid spray which impinges on heated surface as well as by atomization behavior of micro-solid particles. When micro-SN2 spraying cooling was used, an ultra-high cooling heat flux level was achieved during operation, a better cooling performance than that with liquid nitrogen (LN2) spray cooling. As micro-SN2 cooling has the advantage of direct latent heat transport which avoids the film boiling state, the ultra-short time scale heat transfer in a thin boundary layer is more possible than in LN2 spray. The present numerical prediction of the micro-SN2 spray cooling heat flux profile can reasonably reproduce the measurement results of cooling wall heat flux profiles. The application of micro-solid spray as a refrigerant for next generation computer processors is anticipated, and its ultra-high heat flux technology is expected to result in an extensive improvement in the effective cooling performance of large scale supercomputer systems.

The optimal operation of cooling tower systems with variable-frequency control

NASA Astrophysics Data System (ADS)

Cao, Yong; Huang, Liqing; Cui, Zhiguo; Liu, Jing

2018-02-01

This study investigates the energy performance of chiller and cooling tower systems integrated with variable-frequency control for cooling tower fans and condenser water pumps. With regard to an example chiller system serving an office building, Chiller and cooling towers models were developed to assess how different variable-frequency control methods of cooling towers fans and condenser water pumps influence the trade-off between the chiller power, pump power and fan power under various operating conditions. The matching relationship between the cooling tower fans frequency and condenser water pumps frequency at optimal energy consumption of the system is introduced to achieve optimum system performance.

Method for passive cooling liquid metal cooled nuclear reactors, and system thereof

DOEpatents

Hunsbedt, Anstein; Busboom, Herbert J.

1991-01-01

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting from fuel decay during reactor shutdown. The passive cooling system comprises a plurality of partitions surrounding the reactor vessel in spaced apart relation forming intermediate areas for circulating heat transferring fluid which remove and carry away heat from the reactor vessel.

Droplet bubbling evaporatively cools a blowfly.

PubMed

Gomes, Guilherme; Köberle, Roland; Von Zuben, Claudio J; Andrade, Denis V

2018-04-19

Terrestrial animals often use evaporative cooling to lower body temperature. Evaporation can occur from humid body surfaces or from fluids interfaced to the environment through a number of different mechanisms, such as sweating or panting. In Diptera, some flies move tidally a droplet of fluid out and then back in the buccopharyngeal cavity for a repeated number of cycles before eventually ingesting it. This is referred to as the bubbling behaviour. The droplet fluid consists of a mix of liquids from the ingested food, enzymes from the salivary glands, and antimicrobials, associated to the crop organ system, with evidence pointing to a role in liquid meal dehydration. Herein, we demonstrate that the bubbling behaviour also serves as an effective thermoregulatory mechanism to lower body temperature by means of evaporative cooling. In the blowfly, Chrysomya megacephala, infrared imaging revealed that as the droplet is extruded, evaporation lowers the fluid´s temperature, which, upon its re-ingestion, lowers the blowfly's body temperature. This effect is most prominent at the cephalic region, less in the thorax, and then in the abdomen. Bubbling frequency increases with ambient temperature, while its cooling efficiency decreases at high air humidities. Heat transfer calculations show that droplet cooling depends on a special heat-exchange dynamic, which result in the exponential activation of the cooling effect.

Mechanical effects of strong measurement: back-action noise and cooling

NASA Astrophysics Data System (ADS)

Schwab, Keith

2007-03-01

Our recent experiments show that it is now possible to prepare and measure mechanical systems with thermal occupation factors of N˜25 and perform continuous position measurements close to the limits required by the Heisenberg Uncertainty Principle (1). I will discuss our back-action measurements with nanomechanical structures strongly coupled to single electron transistors. We have been able to observe the stochastic back-action forces exerted by the SET as well as a cooling effect which has analogies to cooling in optical cavities. Furthermore, I will discuss progress using optical fields coupled to mechanical modes which show substantial cooling using the pondermotive effects of the photons impacting a flexible dielectric mirror (2). Both of these techniques pave the way to demonstrating the true quantum properties of a mechanical device: squeezed states, superposition states, and entangled states. (1) ``Quantum Measurement Backaction and Cooling Observed with a Nanomechanical Resonator,'' A. Naik, O. Buu, M.D. LaHaye, M.P. Blencowe, A.D. Armour, A.A. Clerk, K.C. Schwab, Nature 443, 193 (2006). (2) ``Self-cooling of a micro-mirror by radiation pressure,'' S. Gigan, H.R. Boehm, M. Patemostro, F. Blaser, G. Langer, J. Hertzberg, K. Schwab, D. Baeuerle, M. Aspelmeyer, A. Zeilinger, Nature 444, 67 (2006).

Quantum speed limit constraints on a nanoscale autonomous refrigerator

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Chiranjib; Misra, Avijit; Bhattacharya, Samyadeb; Pati, Arun Kumar

2018-06-01

Quantum speed limit, furnishing a lower bound on the required time for the evolution of a quantum system through the state space, imposes an ultimate natural limitation to the dynamics of physical devices. Quantum absorption refrigerators, however, have attracted a great deal of attention in the past few years. In this paper, we discuss the effects of quantum speed limit on the performance of a quantum absorption refrigerator. In particular, we show that there exists a tradeoff relation between the steady cooling rate of the refrigerator and the minimum time taken to reach the steady state. Based on this, we define a figure of merit called "bounding second order cooling rate" and show that this scales linearly with the unitary interaction strength among the constituent qubits. We also study the increase of bounding second-order cooling rate with the thermalization strength. We subsequently demonstrate that coherence in the initial three qubit system can significantly increase the bounding second-order cooling rate. We study the efficiency of the refrigerator at maximum bounding second-order cooling rate and, in a limiting case, we show that the efficiency at maximum bounding second-order cooling rate is given by a simple formula resembling the Curzon-Ahlborn relation.

Upgrade to the Birmingham Irradiation Facility

NASA Astrophysics Data System (ADS)

Dervan, P.; French, R.; Hodgson, P.; Marin-Reyes, H.; Parker, K.; Wilson, J.; Baca, M.

2015-10-01

The Birmingham Irradiation Facility was developed in 2013 at the University of Birmingham using the Medical Physics MC40 cyclotron. It can achieve High Luminosity LHC (HL-LHC) fluences of 1015 (1 MeV neutron equivalent (neq)) cm-2 in 80 s with proton beam currents of 1 μA and so can evaluate effectively the performance and durability of detector technologies and new components to be used for the HL-LHC. Irradiations of silicon sensors and passive materials can be carried out in a temperature controlled cold box which moves continuously through the homogenous beamspot. This movement is provided by a pre-configured XY-axis Cartesian robot scanning system. In 2014 the cooling system and cold box were upgraded from a recirculating glycol chiller system to a liquid nitrogen evaporative system. The new cooling system achieves a stable temperature of -50 °C in 30 min and aims to maintain sub-0 °C temperatures on the sensors during irradiations. This paper reviews the design, development, commissioning and performance of the new cooling system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Weihuan; France, David M.; Yu, Wenhua

At present, single-phase liquid, forced convection cooled heat sinks with fins are used to cool power electronics in hybrid electric vehicles (HEVs). Although use of fins in the cooling channels increases heat transfer rates considerably, a second low-temperature radiator and associated pumping system are still required in HEVs. This additional cooling system adds weight and cost while decreasing the efficiency of HEVs. With the objective of eliminating this additional low-temperature radiator and pumping system in HEVs, an alternative cooling technology, subcooled boiling in the cooling channels, was investigated in the present study. Numerical heat transfer simulations were performed using subcooledmore » boiling in the power electronics cooling channels with the coolant supplied from the existing main engine cooling system. Results show that this subcooled boiling system is capable of removing 25% more heat from the power electronics than the conventional forced convection cooling technology, or it can reduce the junction temperature of the power electronics at the current heat removal rate. With the 25% increased heat transfer option, high heat fluxes up to 250 W/cm(2) (typical for wideband-gap semiconductor applications) are possible by using the subcooled boiling system.« less

Effects of milrinone on left ventricular cardiac function during cooling in an intact animal model.

PubMed

Tveita, Torkjel; Sieck, Gary C

2012-08-01

Due to adverse effects of β-receptor agonists reported when applied during hypothermia, left ventricular (LV) cardiac effects of milrinone, a PDE3 inhibitor which mode of action is deprived the sarcolemmal β-receptor-G protein-PKA system, was tested during cooling to 15 °C. Sprague Dawley rats were instrumented to measure left ventricular (LV) pressure-volume changes using a Millar pressure-volume conductance catheter. Core temperature was reduced from 37 to 15 °C (60 min) using internal and external heat exchangers. Milrinone, or saline placebo, was given as continuous i.v. infusions for 30 min at 37 °C and during cooling. In normothermic controls continuous milrinone infusion for 90 min elevated cardiac output (CO) and stroke volume (SV) significantly. Significant differences in cardiac functional variables between the milrinone group and the saline control group during cooling to 15 °C were found: Compared to saline treated animals throughout cooling from 33 to 15 °CSV was significantly elevated in milrinone animals, the index of LV isovolumic relaxation, Tau, was significantly better preserved, and both HR and CO were significantly higher from 33 to 24 °C. Likewise, during cooling between 33 and 28 °C also LVdP/dt(max) was significantly higher in the milrinone group. Milrinone preserved LV systolic and diastolic function at a significantly higher level than in saline controls during cooling to 15 °C. In essential contrast to our previous results when using β-receptor agonists during hypothermia, the present experiment demonstrates the positive inotropic effects of milrinone on LV cardiac function during cooling to 15 °C. Copyright © 2012 Elsevier Inc. All rights reserved.

Citywide Impacts of Cool Roof and Rooftop Solar Photovoltaic Deployment on Near-Surface Air Temperature and Cooling Energy Demand

NASA Astrophysics Data System (ADS)

Salamanca, F.; Georgescu, M.; Mahalov, A.; Moustaoui, M.; Martilli, A.

2016-10-01

Assessment of mitigation strategies that combat global warming, urban heat islands (UHIs), and urban energy demand can be crucial for urban planners and energy providers, especially for hot, semi-arid urban environments where summertime cooling demands are excessive. Within this context, summertime regional impacts of cool roof and rooftop solar photovoltaic deployment on near-surface air temperature and cooling energy demand are examined for the two major USA cities of Arizona: Phoenix and Tucson. A detailed physics-based parametrization of solar photovoltaic panels is developed and implemented in a multilayer building energy model that is fully coupled to the Weather Research and Forecasting mesoscale numerical model. We conduct a suite of sensitivity experiments (with different coverage rates of cool roof and rooftop solar photovoltaic deployment) for a 10-day clear-sky extreme heat period over the Phoenix and Tucson metropolitan areas at high spatial resolution (1-km horizontal grid spacing). Results show that deployment of cool roofs and rooftop solar photovoltaic panels reduce near-surface air temperature across the diurnal cycle and decrease daily citywide cooling energy demand. During the day, cool roofs are more effective at cooling than rooftop solar photovoltaic systems, but during the night, solar panels are more efficient at reducing the UHI effect. For the maximum coverage rate deployment, cool roofs reduced daily citywide cooling energy demand by 13-14 %, while rooftop solar photovoltaic panels by 8-11 % (without considering the additional savings derived from their electricity production). The results presented here demonstrate that deployment of both roofing technologies have multiple benefits for the urban environment, while solar photovoltaic panels add additional value because they reduce the dependence on fossil fuel consumption for electricity generation.

40 CFR 125.136 - As an owner or operator of a new offshore oil and gas extraction facility, what must I collect...

Code of Federal Regulations, 2011 CFR

2011-07-01

... stresses on the source waterbody. (B) Evaluation of potential cooling water intake structure effects. This... (CONTINUED) WATER PROGRAMS CRITERIA AND STANDARDS FOR THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil and Gas Extraction Facilities...

40 CFR 125.136 - As an owner or operator of a new offshore oil and gas extraction facility, what must I collect...

Code of Federal Regulations, 2010 CFR

2010-07-01

... stresses on the source waterbody. (B) Evaluation of potential cooling water intake structure effects. This... (CONTINUED) WATER PROGRAMS CRITERIA AND STANDARDS FOR THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM Requirements Applicable to Cooling Water Intake Structures for New Offshore Oil and Gas Extraction Facilities...

Experiences in solar cooling systems

NASA Astrophysics Data System (ADS)

Ward, D. S.

The results of performance evaluations for nine solar cooling systems are presented, and reasons fow low or high net energy balances are discussed. Six of the nine systems are noted to have performed unfavorably compared to standard cooling systems due to thermal storage losses, excessive system electrical demands, inappropriate control strategies, poor system-to-load matching, and poor chiller performance. A reduction in heat losses in one residential unit increased the total system efficiency by 2.5%, while eliminating heat losses to the building interior increased the efficiency by 3.3%. The best system incorporated a lithium bromide absorption chiller and a Rankine cycle compression unit for a commercial application. Improvements in the cooling tower and fan configurations to increase the solar cooling system efficiency are indicated. Best performances are expected to occur in climates inducing high annual cooling loads.

Temperature Profiles of Different Cooling Methods in Porcine Pancreas Procurement

PubMed Central

Weegman, Brad P.; Suszynski, Thomas M.; Scott, William E.; Ferrer, Joana; Avgoustiniatos, Efstathios S.; Anazawa, Takayuki; O’Brien, Timothy D.; Rizzari, Michael D.; Karatzas, Theodore; Jie, Tun; Sutherland, David ER.; Hering, Bernhard J.; Papas, Klearchos K.

2014-01-01

Background Porcine islet xenotransplantation is a promising alternative to human islet allotransplantation. Porcine pancreas cooling needs to be optimized to reduce the warm ischemia time (WIT) following donation after cardiac death, which is associated with poorer islet isolation outcomes. Methods This study examines the effect of 4 different cooling Methods on core porcine pancreas temperature (n=24) and histopathology (n=16). All Methods involved surface cooling with crushed ice and chilled irrigation. Method A, which is the standard for porcine pancreas procurement, used only surface cooling. Method B involved an intravascular flush with cold solution through the pancreas arterial system. Method C involved an intraductal infusion with cold solution through the major pancreatic duct, and Method D combined all 3 cooling Methods. Results Surface cooling alone (Method A) gradually decreased core pancreas temperature to < 10 °C after 30 minutes. Using an intravascular flush (Method B) improved cooling during the entire duration of procurement, but incorporating an intraductal infusion (Method C) rapidly reduced core temperature 15–20 °C within the first 2 minutes of cooling. Combining all methods (Method D) was the most effective at rapidly reducing temperature and providing sustained cooling throughout the duration of procurement, although the recorded WIT was not different between Methods (p=0.36). Histological scores were different between the cooling Methods (p=0.02) and the worst with Method A. There were differences in histological scores between Methods A and C (p=0.02) and Methods A and D (p=0.02), but not between Methods C and D (p=0.95), which may highlight the importance of early cooling using an intraductal infusion. Conclusions In conclusion, surface cooling alone cannot rapidly cool large (porcine or human) pancreata. Additional cooling with an intravascular flush and intraductal infusion results in improved core porcine pancreas temperature profiles during procurement and histopathology scores. These data may also have implications on human pancreas procurement since use of an intraductal infusion is not common practice. PMID:25040217

Theoretical model for Sub-Doppler Cooling with EIT System

NASA Astrophysics Data System (ADS)

He, Peiru; Tengdin, Phoebe; Anderson, Dana; Rey, Ana Maria; Holland, Murray

2016-05-01

We propose a of sub-Doppler cooling mechanism that takes advantage of the unique spectral features and extreme dispersion generated by the so-called Electromagnetically Induced Transparency (EIT) effect, a destructive quantum interference phenomenon experienced by atoms with Lambda-shaped energy levels when illuminated by two light fields with appropriate frequencies. By detuning the probe lasers slightly from the ``dark resonance'', we observe that atoms can be significantly cooled down by the strong viscous force within the transparency window, while being just slightly heated by the diffusion caused by the small absorption near resonance. In contrast to polarization gradient cooling or EIT sideband cooling, no external magnetic field or external confining potential are required. Using a semi-classical method, analytical expressions, and numerical simulations, we demonstrate that the proposed EIT cooling method can lead to temperatures well below the Doppler limit. This work is supported by NSF and NIST.

Cooling water distribution system

DOEpatents

Orr, Richard

1994-01-01

A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using an interconnected series of radial guide elements, a plurality of circumferential collector elements and collector boxes to collect and feed the cooling water into distribution channels extending along the curved surface of the steel containment vessel. The cooling water is uniformly distributed over the curved surface by a plurality of weirs in the distribution channels.

Cooling of superconducting devices by liquid storage and refrigeration unit

DOEpatents

Laskaris, Evangelos Trifon; Urbahn, John Arthur; Steinbach, Albert Eugene

2013-08-20

A system is disclosed for cooling superconducting devices. The system includes a cryogen cooling system configured to be coupled to the superconducting device and to supply cryogen to the device. The system also includes a cryogen storage system configured to supply cryogen to the device. The system further includes flow control valving configured to selectively isolate the cryogen cooling system from the device, thereby directing a flow of cryogen to the device from the cryogen storage system.

Heat rejection system

DOEpatents

Smith, Gregory C.; Tokarz, Richard D.; Parry, Jr., Harvey L.; Braun, Daniel J.

1980-01-01

A cooling system for rejecting waste heat consists of a cooling tower incorporating a plurality of coolant tubes provided with cooling fins and each having a plurality of cooling channels therein, means for directing a heat exchange fluid from the power plant through less than the total number of cooling channels to cool the heat exchange fluid under normal ambient temperature conditions, means for directing water through the remaining cooling channels whenever the ambient temperature rises above the temperature at which dry cooling of the heat exchange fluid is sufficient and means for cooling the water.

Absorber modeling for NGCC carbon capture with aqueous piperazine.

PubMed

Zhang, Yue; Freeman, Brice; Hao, Pingjiao; Rochelle, Gary T

2016-10-20

A hybrid system combining amine scrubbing with membrane technology for carbon capture from natural gas combined cycle (NGCC) power plants is proposed in this paper. In this process, the CO 2 in the flue gas can be enriched from 4% to 18% by the membrane, and the amine scrubbing system will have lower capture costs. Aqueous piperazine (PZ) is chosen as the solvent. Different direct contact cooler (DCC) options, multiple absorber operating conditions, optimal intercooling designs, and different cooling options have been evaluated across a wide range of inlet CO 2 . Amine scrubbing without DCC is a superior design for NGCC carbon capture. Pump-around cooling at the bottom of the absorber can effectively manage the temperature of the hot flue gas, and still be effective for CO 2 absorption. The absorber gas inlet must be designed to avoid excessive localized temperature and solvent evaporation. When the inlet CO 2 increases from 4% to 18%, total absorber CAPEX decreases by 60%; another 10% of the total absorber CAPEX can be saved by eliminating the DCC. In-and-out intercooling works well for high CO 2 , while pump-around intercooling is more effective for low CO 2 . Dry cooling requires more packing and energy but appears to be technically and economically feasible if cooling water availability is limited.

Solar heating and cooling technical data and systems analysis

NASA Technical Reports Server (NTRS)

Christensen, D. L.

1976-01-01

The acquisition and processing of selected parametric data for inclusion in a computerized Data Base using the Marshall Information Retrieval and Data System (MIRADS) developed by NASA-MSFC is discussed. This data base provides extensive technical and socioeconomic information related to solar energy heating and cooling on a national scale. A broadly based research approach was used to assist in the support of program management and the application of a cost-effective program for solar energy development and demonstration.

Compliant Metal Enhanced Convection Cooled Reverse-Flow Annular Combustor

NASA Technical Reports Server (NTRS)

Paskin, Marc D.; Acosta, Waldo A.

1994-01-01

A joint Army/NASA program was conducted to design, fabricate, and test an advanced, reverse-flow, small gas turbine combustor using a compliant metal enhanced (CME) convection wall cooling concept. The objectives of this effort were to develop a design method (basic design data base and analysis) for the CME cooling technique and tben demonstrate its application to an advanced cycle, small, reverse-flow combustor with 3000 F (1922 K) burner outlet temperature (BOT). The CME concept offers significant improvements in wall cooling effectiveness resulting in a large reduction in cooling air requirements. Therefore, more air is available for control of burner outlet temperature pattern in addition to the benefit of improved efficiency, reduced emissions, and smoke levels. Rig test results demonstrated the benefits and viability of the CME concept meeting or exceeding the aerothermal performance and liner wall temperature characteristics of similar lower temperature-rise combustors, achieving 0.15 pattern factor at 3000 F (1922 K) BOT, while utilizing approximately 80 percent less cooling air than conventional, film-cooled combustion systems.

A novel head-neck cooling device for concussion injury in contact sports

PubMed Central

Wang, Huan; Wang, Bonnie; Jackson, Kevin; Miller, Claire M.; Hasadsri, Linda; Llano, Daniel; Rubin, Rachael; Zimmerman, Jarred; Johnson, Curtis; Sutton, Brad

2015-01-01

Emerging research on the long-term impact of concussions on athletes has allowed public recognition of the potentially devastating effects of these and other mild head injuries. Mild traumatic brain injury (mTBI) is a multifaceted disease for which management remains a clinical challenge. Recent pre-clinical and clinical data strongly suggest a destructive synergism between brain temperature elevation and mTBI; conversely, brain hypothermia, with its broader, pleiotropic effects, represents the most potent neuro-protectant in laboratory studies to date. Although well-established in selected clinical conditions, a systemic approach to accomplish regional hypothermia has failed to yield an effective treatment strategy in traumatic brain injury (TBI). Furthermore, although systemic hypothermia remains a potentially valid treatment strategy for moderate to severe TBIs, it is neither practical nor safe for mTBIs. Therefore, selective head-neck cooling may represent an ideal strategy to provide therapeutic benefits to the brain. Optimizing brain temperature management using a National Aeronautics and Space Administration (NASA) spacesuit spinoff head-neck cooling technology before and/or after mTBI in contact sports may represent a sensible, practical, and effective method to potentially enhance recover and minimize post-injury deficits. In this paper, we discuss and summarize the anatomical, physiological, preclinical, and clinical data concerning NASA spinoff head-neck cooling technology as a potential treatment for mTBIs, particularly in the context of contact sports. PMID:28123788

Description and cost analysis of a deluge dry/wet cooling system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiles, L.E.; Bamberger, J.A.; Braun, D.J.

1978-06-01

The use of combined dry/wet cooling systems for large base-load power plants offers the potential for significant water savings as compared to evaporatively cooled power plants and significant cost savings in comparison to dry cooled power plants. The results of a detailed engineering and cost study of one type of dry/wet cooling system are described. In the ''deluge'' dry/wet cooling method, a finned-tube heat exchanger is designed to operate in the dry mode up to a given ambient temperature. To avoid the degradation of performance for higher ambient temperatures, water (the delugeate) is distributed over a portion of the heatmore » exchanger surface to enhance the cooling process by evaporation. The deluge system used in this study is termed the HOETERV system. The HOETERV deluge system uses a horizontal-tube, vertical-plate-finned heat exchanger. The delugeate is distributed at the top of the heat exchanger and is allowed to fall by gravity in a thin film on the face of the plate fin. Ammonia is used as the indirect heat transfer medium between the turbine exhaust steam and the ambient air. Steam is condensed by boiling ammonia in a condenser/reboiler. The ammonia is condensed in the heat exchanger by inducing airflow over the plate fins. Various design parameters of the cooling system have been studied to evaluate their impact on the optimum cooling system design and the power-plant/utility-system interface. Annual water availability was the most significant design parameter. Others included site meteorology, heat exchanger configuration and air flow, number and size of towers, fan system design, and turbine operation. It was concluded from this study that the HOETERV deluge system of dry/wet cooling, using ammonia as an intermediate heat transfer medium, offers the potential for significant cost savings compared with all-dry cooling, while achieving substantially reduced water consumption as compared to an evaporatively cooled power plant. (LCL)« less

Numerical modelling of series-parallel cooling systems in power plant

NASA Astrophysics Data System (ADS)

Regucki, Paweł; Lewkowicz, Marek; Kucięba, Małgorzata

2017-11-01

The paper presents a mathematical model allowing one to study series-parallel hydraulic systems like, e.g., the cooling system of a power boiler's auxiliary devices or a closed cooling system including condensers and cooling towers. The analytical approach is based on a set of non-linear algebraic equations solved using numerical techniques. As a result of the iterative process, a set of volumetric flow rates of water through all the branches of the investigated hydraulic system is obtained. The calculations indicate the influence of changes in the pipeline's geometrical parameters on the total cooling water flow rate in the analysed installation. Such an approach makes it possible to analyse different variants of the modernization of the studied systems, as well as allowing for the indication of its critical elements. Basing on these results, an investor can choose the optimal variant of the reconstruction of the installation from the economic point of view. As examples of such a calculation, two hydraulic installations are described. One is a boiler auxiliary cooling installation including two screw ash coolers. The other is a closed cooling system consisting of cooling towers and condensers.

Phase Transformations During Cooling of Automotive Steels

NASA Astrophysics Data System (ADS)

Padgett, Matthew C.

This thesis explores the effect of cooling rate on the microstructure and phases in advanced high strength steels (AHSS). In the manufacturing of automobiles, the primary joining mechanism for steel is resistance spot welding (RSW), a process that produces a high heat input and rapid cooling in the welded metal. The effect of RSW on the microstructure of these material systems is critical to understanding their mechanical properties. A dual phase steel, DP-600, and a transformation induced plasticity bainitic-ferritic steel, TBF-1180, were studied to assess the changes to their microstructure that take place in controlled cooling environments and in uncontrolled cooling environments, i.e. resistance spot welding. Continuous cooling transformation (CCT) diagrams were developed using strip specimens of DP-600 and TBF-1180 to determine the phase transformations that occur as a function of cooling rate. The resulting phases were determined using a thermal-mechanical simulator and dilatometry, combined with light optical microscopy and hardness measurements. The resulting phases were compared with RSW specimens where cooling rate was controlled by varying the welding time for two-plate welds. Comparisons were drawn between experimental welds of DP-600 and simulations performed using a commercial welding software. The type and quantity of phases present after RSW were examined using a variety of techniques, including light optical microscopy using several etchants, hardness measurements, and x-ray diffraction (XRD).

Development and Evaluation of Active Thermal Management System for Lithium-Ion Batteries using Solid-State Thermoelectric Heat Pump and Heat Pipes with Electric Vehicular Applications

NASA Astrophysics Data System (ADS)

Parekh, Bhaumik Kamlesh

Lithium-Ion batteries have become a popular choice for use in energy storage systems in electric vehicles (EV) and Hybrid electric vehicles (HEV) because of high power and high energy density. But the use of EV and HEV in all climates demands for a battery thermal management system (BTMS) since temperature effects their performance, cycle life and, safety. Hence the BTMS plays a crucial role in the performance of EV and HEV. In this paper, three thermal management systems are studied: (a) simple aluminum as heat spreader material, (b) heat pipes as heat spreader, and (c) advanced combined solid state thermoelectric heat pump (TE) and heat pipe system; these will be subsequently referred to as Design A, B and C, respectively. A detailed description of the designs and the experimental setup is presented. The experimental procedure is divided into two broad categories: Cooling mode and Warming-up mode. Cooling mode covers the conditions when a BTMS is responsible to cool the battery pack through heat dissipation and Warming-up mode covers the conditions when the BTMS is responsible to warm the battery pack in a low temperature ambient condition, maintaining a safe operating temperature of the battery pack in both modes. The experimental procedure analyzes the thermal management system by evaluating the effect of each variable like heat sink area, battery heat generation rate, cooling air temperature, air flow rate and TE power on parameters like maximum temperature of the battery pack (T max), maximum temperature difference (DeltaT) and, heat transfer through heat sink/cooling power of TE (Q c). The results show that Design C outperforms Design A and Design B in spite of design issues which reduce its efficiency, but can still be improved to achieve better performance.

Floating Loop System For Cooling Integrated Motors And Inverters Using Hot Liquid Refrigerant

DOEpatents

Hsu, John S [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Coomer, Chester [Knoxville, TN; Marlino, Laura D [Oak Ridge, TN

2006-02-07

A floating loop vehicle component cooling and air-conditioning system having at least one compressor for compressing cool vapor refrigerant into hot vapor refrigerant; at least one condenser for condensing the hot vapor refrigerant into hot liquid refrigerant by exchanging heat with outdoor air; at least one floating loop component cooling device for evaporating the hot liquid refrigerant into hot vapor refrigerant; at least one expansion device for expanding the hot liquid refrigerant into cool liquid refrigerant; at least one air conditioning evaporator for evaporating the cool liquid refrigerant into cool vapor refrigerant by exchanging heat with indoor air; and piping for interconnecting components of the cooling and air conditioning system.

Thermal pollution consequences of the implementation of the president's energy message on increased coal utilization.

PubMed Central

Parker, F L

1979-01-01

The thermal consequences of coal utilization are most meaningfully assessed in comparison with the form of power generation replaced by coal which is most likely nuclear. The different effects are influenced by siting decisions and the intrinsic thermal efficiencies of the two fuel systems. Nuclear power plants discharge 50% more waste Rheat to the atmosphere through cooling towers or to a water body than coal-fired plants. Coal-fired plants require about 2/3 as much water as nuclear power plants. Nearly every property of water is affected nonlinearly by temperature, and biological effects may amplify these changes because protein denaturation takes place more rapidly above 30 degrees C and these high temperatures affect bactericidal and viricidal activity of chlorine compounds. Usually algal populations change from a dominance of diatoms and green algae to dominance by blue-green algae. All organisms experience elevated metabolic rates at higher temperatures which may affect total energy needs, foraging ability, reproduction, migration and susceptibility to disease. Intake structures inevitably draw many organisms into the cooling system of a power plant, but the number and kind are influenced by its location, configuration, and mode of operation. Use of water recirculation systems reduces water use and with it, the number of organisms entrained. Mechanical damage in the cooling system to small organisms is generally low, but fish and their larvae and eggs may be seriously damaged. Discharge effects may also be severe but are generally local. The near field, where there are strong shear velocities and rapid temperature changes are particularly stressful to fish, and stringent limitations on the timing and strength of discharges may be required to reduce these stresses to nondamaging levels. Off-stream cooling systems may increase cloudiness, ground fog, precipitation, temperature and local winds, but these effects generally extend no further than 1000 m even in winter. There is considerable potential for using condenser cooling water for agricultural and aquacultural purposes such as irrigation, frost protection, undersoil heating, greenhouse heating and climate control. However, over the next few decades little of this waste heat is likely to be used creatively. The thermal consequences of implementing NEP are locally serious but do not pose regional problems. Creative use of the waste heat for aquaculture, agriculture, cogeneration, and power for energy intensive industries can be a powerful means of mitigating undesirable effects. PMID:540623

Optomechanical performance of 3D-printed mirrors with embedded cooling channels and substructures

NASA Astrophysics Data System (ADS)

Mici, Joni; Rothenberg, Bradley; Brisson, Erik; Wicks, Sunny; Stubbs, David M.

2015-09-01

Advances in 3D printing technology allow for the manufacture of topologically complex parts not otherwise feasible through conventional manufacturing methods. Maturing metal and ceramic 3D printing technologies are becoming more adept at printing complex shapes, enabling topologically intricate mirror substrates. One application area that can benefit from additive manufacturing is reflective optics used in high energy laser (HEL) systems that require materials with a low coefficient of thermal expansion (CTE), high specific stiffness, and (most importantly) high thermal conductivity to effectively dissipate heat from the optical surface. Currently, the limits of conventional manufacturing dictate the topology of HEL optics to be monolithic structures that rely on passive cooling mechanisms and high reflectivity coatings to withstand laser damage. 3D printing enables the manufacture of embedded cooling channels in metallic mirror substrates to allow for (1) active cooling and (2) tunable structures. This paper describes the engineering and analysis of an actively cooled composite optical structure to demonstrate the potential of 3D printing on the improvement of optomechanical systems.

Crawl space assisted heat pump. [using stored ground heat

NASA Technical Reports Server (NTRS)

Ternes, M. P.

1980-01-01

A variety of experiments and simulations, currently being designed or underway, to determine the feasibility of conditioning the source air of an air to air heat pump using stored ground heat or cool to produce higher seasonal COP's and net energy savings are discussed. The ground would condition ambient air as it is drawn through the crawl space of a house. Tests designed to evaluate the feasibility of the concept, to determine the amount of heat or cool available from the ground, to study the effect of the system on the heating and cooling loads of the house, to study possible mechanisms which could enhance heat flow through the ground, and to determine if diurnal temperature swings are necessary to achieve successful system performance are described.

Data center cooling system

DOEpatents

Chainer, Timothy J; Dang, Hien P; Parida, Pritish R; Schultz, Mark D; Sharma, Arun

2015-03-17

A data center cooling system may include heat transfer equipment to cool a liquid coolant without vapor compression refrigeration, and the liquid coolant is used on a liquid cooled information technology equipment rack housed in the data center. The system may also include a controller-apparatus to regulate the liquid coolant flow to the liquid cooled information technology equipment rack through a range of liquid coolant flow values based upon information technology equipment temperature thresholds.

Active Cooling of Oil after Deep-frying.

PubMed

Totani, Nagao; Yasaki, Naoko; Doi, Rena; Hasegawa, Etsuko

2017-10-01

Oil used for deep-frying is often left to stand after cooking. A major concern is oxidation during standing that might be avoidable, especially in the case of oil used repeatedly for commercial deep-frying as this involves large volumes that are difficult to cool in a conventional fryer. This paper describes a method to minimize oil oxidation. French fries were deep-fried and the oil temperature decreased in a manner typical for a commercial deep-fryer. The concentration of polar compounds generated from thermally oxidized oil remarkably increased at temperature higher than 100°C but little oxidation occurred below 60°C. Heating the oil showed that the peroxide and polar compound content did not increase when the oil was actively cooled using a running water-cooled Graham-type condenser system to cool the oil from 180°C to room temperature within 30 min. When French fries were fried and the oil was then immediately cooled using the condenser, the polar compound content during cooling did not increase. Our results demonstrate that active cooling of heated oil is simple and quite effective for inhibiting oxidation.

Experimental study of hybrid interface cooling system using air ventilation and nanofluid

NASA Astrophysics Data System (ADS)

Rani, M. F. H.; Razlan, Z. M.; Bakar, S. A.; Desa, H.; Wan, W. K.; Ibrahim, I.; Kamarrudin, N. S.; Bin-Abdun, Nazih A.

2017-09-01

The hybrid interface cooling system needs to be established to chill the battery compartment of electric car and maintained its ambient temperature inside the compartment between 25°C to 35°C. The air cooling experiment has been conducted to verify the cooling capacity, compressor displacement volume, dehumidifying value and mass flow rate of refrigerant (R-410A). At the same time, liquid cooling system is analysed theoretically by comparing the performance of two types of nanofluid, i.e., CuO + Water and Al2O3 + Water, based on the heat load generated inside the compartment. In order for the result obtained to be valid and reliable, several assumptions are considered during the experimental and theoretical analysis. Results show that the efficiency of the hybrid interface cooling system is improved as compared to the individual cooling system.

System and method of active vibration control for an electro-mechanically cooled device

DOEpatents

Lavietes, Anthony D.; Mauger, Joseph; Anderson, Eric H.

2000-01-01

A system and method of active vibration control of an electro-mechanically cooled device is disclosed. A cryogenic cooling system is located within an environment. The cooling system is characterized by a vibration transfer function, which requires vibration transfer function coefficients. A vibration controller generates the vibration transfer function coefficients in response to various triggering events. The environments may differ by mounting apparatus, by proximity to vibration generating devices, or by temperature. The triggering event may be powering on the cooling system, reaching an operating temperature, or a reset action. A counterbalance responds to a drive signal generated by the vibration controller, based on the vibration signal and the vibration transfer function, which adjusts vibrations. The method first places a cryogenic cooling system within a first environment and then generates a first set of vibration transfer function coefficients, for a vibration transfer function of the cooling system. Next, the cryogenic cooling system is placed within a second environment and a second set of vibration transfer function coefficients are generated. Then, a counterbalance is driven, based on the vibration transfer function, to reduce vibrations received by a vibration sensitive element.

Exterior Insulation Implications for Heating and Cooling Systems in Cold Climates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herk, Anastasia; Poerschke, Andrew

The New York State Energy Research and Development Authority (NYSERDA) is interested in finding cost-effective solutions for deep energy retrofits (DERs) related to exterior wall insulation in a cold climate, with targets of 50% peak load reduction and 50% space conditioning energy savings. The U.S. Department of Energy Building America team, IBACOS, in collaboration with GreenHomes America, Inc. (GHA), was contracted by NYSERDA to research exterior wall insulation solutions. In addition to exterior wall insulation, the strategies included energy upgrades where needed in the attic, mechanical and ventilation systems, basement, band joist, walls, and floors. Under Building America, IBACOS ismore » studying the impact of a “thermal enclosure” DER on the sizing of the space conditioning system and the occupant comfort if the thermal capacity of the heating and cooling system is dramatically downsized without any change in the existing heating and cooling distribution system (e.g., size, tightness and supply outlet configurations).« less

Design and evaluation of active cooling systems for Mach 6 cruise vehicle wings

NASA Technical Reports Server (NTRS)

Mcconarty, W. A.; Anthony, F. M.

1971-01-01

Active cooling systems, which included transpiration, film, and convective cooling concepts, are examined. Coolants included hydrogen, helium, air, and water. Heat shields, radiation barriers, and thermal insulation are considered to reduce heat flow to the cooling systems. Wing sweep angles are varied from 0 deg to 75 deg and wing leading edge radii of 0.05 inch and 2.0 inches are examined. Structural temperatures are varied to allow comparison of aluminum alloy, titanium alloy, and superalloy structural materials. Cooled wing concepts are compared among themselves, and with the uncooled concept on the basis of structural weight, cooling system weight, and coolant weight.

A method for increasing the homogeneity of the temperature distribution during magnetic fluid hyperthermia with a Fe-Cr-Nb-B alloy in the presence of blood vessels

NASA Astrophysics Data System (ADS)

Tang, Yundong; Flesch, Rodolfo C. C.; Jin, Tao

2017-06-01

Magnetic hyperthermia ablates tumor cells by absorbing the thermal energy from magnetic nanoparticles (MNPs) under an external alternating magnetic field. The blood vessels (BVs) within tumor region can generally reduce treatment effectiveness due to the cooling effect of blood flow. This paper aims to investigate the cooling effect of BVs on the temperature field of malignant tumor regions using a complex geometric model and numerical simulation. For deriving the model, the Navier-Stokes equation for blood flow is combined with Pennes bio-heat transfer equation for human tissue. The effects on treatment temperature caused by two different BV distributions inside a mammary tumor are analyzed through numerical simulation under different conditions of flow rate considering a Fe-Cr-Nb-B alloy, which has low Curie temperature ranging from 42 °C to 45 °C. Numerical results show that the multi-vessel system has more obvious cooling effects than the single vessel one on the temperature field distribution for hyperthermia. Besides, simulation results show that the temperature field within tumor area can also be influenced by the velocity and diameter of BVs. To minimize the cooling effect, this article proposes a treatment method based on the increase of the thermal energy provided to MNPs associated with the adoption of low Curie temperature particles recently reported in literature. Results demonstrate that this approach noticeably improves the uniformity of the temperature field, and shortens the treatment time in a Fe-Cr-Nb-B system, thus reducing the side effects to the patient.

Enrichment of PCDDs/PCDFs in the cooling system of municipal solid waste incineration plants.

PubMed

Kim, Sam-Cwan; Lee, Kil-Chul; Kim, Ki-Heon; Kwon, Myung-Hee; Song, Geum-Ju

2007-01-01

This study measured the levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs), destroyed or formed in combustors and re-synthesized in cooling systems. For the proper control of PCDDs/PCDFs in municipal solid waste (MSW) incinerators, three grate-type MSW incinerators were selected, two of which had boilers, and one of which had a water spray tower (WST) as a cooling system. At the combustor outlets, dusts were in the range of 1640-4270 mg/Sm3 and PCDDs/PCDFs were in the range of 0.103-2.619 ng-TEQ/Sm3, showing the different values according to the grate structure of combustor and the flow direction of flue gas. After the flue gases passed through the cooling system, PCDDs/PCDFs at the waste heat boiler (WHB) outlets were enriched to levels that were 10.8-13.6 times higher than those at the furnace outlets, but PCDDs/PCDFs at the WST outlet was reduced to 5% of the level found at the furnace outlet. The emission patterns, such as the ratio of PCDFs to PCDDs, the ratio of gaseous-phase to particulate-phase PCDDs/PCDFs, and the compositional percentiles of each 2,3,7,8-substituted congener varied according to the types of air pollution control devices (APCDs). Reducing re-synthesis in the cooling system rather than enhancing the removal efficiencies of the APCDs seems to be more effective for lowering the levels of PCDDs/PCDFs in MSW incineration plants.

Sub-cooled liquid nitrogen cryogenic system with neon turbo-refrigerator for HTS power equipment

NASA Astrophysics Data System (ADS)

Yoshida, S.; Hirai, H.; Nara, N.; Ozaki, S.; Hirokawa, M.; Eguchi, T.; Hayashi, H.; Iwakuma, M.; Shiohara, Y.

2014-01-01

We developed a prototype sub-cooled liquid nitrogen (LN) circulation system for HTS power equipment. The system consists of a neon turbo-Brayton refrigerator with a LN sub-cooler and LN circulation pump unit. The neon refrigerator has more than 2 kW cooling power at 65 K. The LN sub-cooler is a plate-fin type heat exchanger and is installed in a refrigerator cold box. In order to carry out the system performance tests, a dummy cryostat having an electric heater was set instead of a HTS power equipment. Sub-cooled LN is delivered into the sub-cooler by the LN circulation pump and cooled within it. After the sub-cooler, sub-cooled LN goes out from the cold box to the dummy cryostat, and comes back to the pump unit. The system can control an outlet sub-cooled LN temperature by adjusting refrigerator cooling power. The refrigerator cooling power is automatically controlled by the turbo-compressor rotational speed. In the performance tests, we increased an electric heater power from 200 W to 1300 W abruptly. We confirmed the temperature fluctuation was about ±1 K. We show the cryogenic system details and performance test results in this paper.

Effects of high pressure on microstructure evolution and crystallization mechanisms during solidification of nickel

NASA Astrophysics Data System (ADS)

Zhang, Hai-Tao; Mo, Yun-Fei; Liu, Rang-Su; Tian, Ze-An; Liu, Hai-Rong; Hou, Zhao-Yang; Zhou, Li-Li; Liang, Yong-Chao; Peng, Ping

2018-03-01

To deeply understand the effects of high pressure on microstructural evolutions and crystallization mechanisms of liquid metal Ni during solidification process, MD simulation studies have been performed under 7 pressures of 0 ˜ 30 GPa, at cooling rate of 1.0 × 1011 K s-1. Adopting several microstructural analyzing methods, especially the cluster-type index method (CTIM-2) to analyze the local microstructures in the system. It is found that the pressure has important influence on the formation and evolution of microstructures, especially of the main basic clusters in the system. All the simulation systems are directly solidified into crystal structures, and the 1421, 1422, 1441 and 1661 bond-types, as well the FCC (12 0 0 0 12 0), HCP (12 0 0 0 6 6) and BCC (14 6 0 8 0 0) clusters play a key role in the microstructure transitions from liquid to crystal structures. The crystallization temperature T c is enhanced almost linearly with the increase of pressure. Highly interesting, it is found for the first time that there is an important phase transformation point from FCC to BCC structures between 20 ˜ 22.5 GPa during the solidification processes from the same initial liquid system at the same cooling rate. And the effect of increasing pressure is similar to that of decreasing cooling rate for the phase transformation of microstructures during solidification process of liquid metal Ni system, though they have different concrete effecting mechanisms.

Experimental evaluation of refrigerant mass charge and ambient air temperature effects on performance of air-conditioning systems

NASA Astrophysics Data System (ADS)

Deymi-Dashtebayaz, Mahdi; Farahnak, Mehdi; Moraffa, Mojtaba; Ghalami, Arash; Mohammadi, Nima

2018-03-01

In this paper the effects of refrigerant charge amount and ambient air temperature on performance and thermodynamic condition of refrigerating cycle in the split type air-conditioner have been investigated. Optimum mass charge is the point at which the energy efficiency ratio (EER) of refrigeration cycle becomes the maximum. Experiments have been conducted over a range of refrigerant mass charge from 540 to 840 g and a range of ambient temperature from 27 to 45 °C, in a 12,000 Btu/h split air-conditioner as case study. The various parameters have been considered to evaluate the cooling rate, energy efficiency ratio (EER), mass charge effect and thermodynamic cycle of refrigeration system with R22 refrigerant gas. Results confirmed that the lack of appropriate refrigerant mass charge causes the refrigeration system not to reach its maximum cooling capacity. The highest cooling capacity achieved was 3.2 kW (11,000 Btu/h). The optimum mass charge and corresponding EER of studied system have been obtained about 640 g and 2.5, respectively. Also, it is observed that EER decreases by 30% as ambient temperature increases from 27 °C to 45 °C. By optimization of the refrigerant mass charge in refrigerating systems, about 785 GWh per year of electric energy can be saved in Iran's residential sector.

Novel Power Electronics Three-Dimensional Heat Exchanger: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennion, K.; Cousineau, J.; Lustbader, J.

2014-08-01

Electric drive systems for vehicle propulsion enable technologies critical to meeting challenges for energy, environmental, and economic security. Enabling cost-effective electric drive systems requires reductions in inverter power semiconductor area. As critical components of the electric drive system are made smaller, heat removal becomes an increasing challenge. In this paper, we demonstrate an integrated approach to the design of thermal management systems for power semiconductors that matches the passive thermal resistance of the packaging with the active convective cooling performance of the heat exchanger. The heat exchanger concept builds on existing semiconductor thermal management improvements described in literature and patents,more » which include improved bonded interface materials, direct cooling of the semiconductor packages, and double-sided cooling. The key difference in the described concept is the achievement of high heat transfer performance with less aggressive cooling techniques by optimizing the passive and active heat transfer paths. An extruded aluminum design was selected because of its lower tooling cost, higher performance, and scalability in comparison to cast aluminum. Results demonstrated a heat flux improvement of a factor of two, and a package heat density improvement over 30%, which achieved the thermal performance targets.« less

NASA Microclimate Cooling Challenges

NASA Technical Reports Server (NTRS)

Trevino, Luis A.

2004-01-01

The purpose of this outline form presentation is to present NASA's challenges in microclimate cooling as related to the spacesuit. An overview of spacesuit flight-rated personal cooling systems is presented, which includes a brief history of cooling systems from Gemini through Space Station missions. The roles of the liquid cooling garment, thermal environment extremes, the sublimator, multi-layer insulation, and helmet visor UV and solar coatings are reviewed. A second section is presented on advanced personal cooling systems studies, which include heat acquisition studies on cooling garments, heat rejection studies on water boiler & radiators, thermal storage studies, and insulation studies. Past and present research and development and challenges are summarized for the advanced studies.

Simulated responses of terrestrial aridity to black carbon and sulfate aerosols

NASA Astrophysics Data System (ADS)

Lin, L.; Gettelman, A.; Xu, Y.; Fu, Q.

2016-01-01

Aridity index (AI), defined as the ratio of precipitation to potential evapotranspiration (PET), is a measure of the dryness of terrestrial climate. Global climate models generally project future decreases of AI (drying) associated with global warming scenarios driven by increasing greenhouse gas and declining aerosols. Given their different effects in the climate system, scattering and absorbing aerosols may affect AI differently. Here we explore the terrestrial aridity responses to anthropogenic black carbon (BC) and sulfate (SO4) aerosols with Community Earth System Model simulations. Positive BC radiative forcing decreases precipitation averaged over global land at a rate of 0.9%/°C of global mean surface temperature increase (moderate drying), while BC radiative forcing increases PET by 1.0%/°C (also drying). BC leads to a global decrease of 1.9%/°C in AI (drying). SO4 forcing is negative and causes precipitation a decrease at a rate of 6.7%/°C cooling (strong drying). PET also decreases in response to SO4 aerosol cooling by 6.3%/°C cooling (contributing to moistening). Thus, SO4 cooling leads to a small decrease in AI (drying) by 0.4%/°C cooling. Despite the opposite effects on global mean temperature, BC and SO4 both contribute to the twentieth century drying (AI decrease). Sensitivity test indicates that surface temperature and surface available energy changes dominate BC- and SO4-induced PET changes.

10 CFR Appendix B to Subpart A of... - Environmental Effect of Renewing the Operating License of a Nuclear Power Plant

Code of Federal Regulations, 2011 CFR

2011-01-01

...). Aquatic Ecology (for all plants) Refurbishment 1 SMALL. During plant shutdown and refurbishment there will... cooling ponds and is not expected to be a problem during the license renewal term. Aquatic Ecology (for...)(ii)(B). Aquatic Ecology (for plants with cooling-tower-based heat dissipation systems) Entrainment of...

Gas hydrate cool storage system

DOEpatents

Ternes, Mark P.; Kedl, Robert J.

1985-01-01

This invention is a process for formation of a gas hydrate to be used as a cool storage medium using a refrigerant in water. Mixing of the immiscible refrigerant and water is effected by addition of a surfactant and agitation. The difficult problem of subcooling during the process is overcome by using the surfactant and agitation and performance of the process significantly improves and approaches ideal.

Thermo-mechanical analysis of an internal cooling system with various configurations of a combustion liner after shell

NASA Astrophysics Data System (ADS)

Moon, Hokyu; Kim, Kyung Min; Park, Jun Su; Kim, Beom Seok; Cho, Hyung Hee

2015-12-01

The after-shell section, which is part of the gas turbine combustion liner, is exposed to the hottest combustion gas. Various cooling schemes have been applied to protect against severe thermal load. However, there is a significant discrepancy in the thermal expansion with large temperature differences, resulting in thermo-mechanical crack formation. In this study, to reduce combustion liner damage, thermo-mechanical analysis was conducted on three after-shell section configurations: inline-discrete divider wall, staggered divider wall, and swirler wall arrays. These array components are well-known heat-transfer enhancement structures in the duct. In the numerical analyses, the heat transfer characteristics, temperature and thermo-mechanical stress distribution were evaluated using finite volume method and finite element method commercial codes. As a result, we demonstrated that the temperature and the thermo-mechanical stress distribution were readily dependent on the structural array for cooling effectiveness and structural support in each modified cooling system. Compared with the reference model, the swirler wall array was most effective in diminishing the thermo-mechanical stress concentration, especially on the inner ring that is vulnerable to crack formation.

Hemodynamic and Thermal Responses to Head and Neck Cooling in Men and Women

NASA Technical Reports Server (NTRS)

Ku, Yu-Tsuan E.; Montgomery, Leslie D.; Carbo, Jorge E.; Webbon, Bruce W.

1995-01-01

Personal cooling systems are used to alleviate symptoms of multiple sclerosis and to prevent increased core temperature during daily activities. Configurations of these systems include passive ice vests and circulating liquid cooling garments (LCGs) in the forms of vests, cooling caps and combined head and neck cooling systems. However, little information is available oil the amount or heat that can be extracted from the body with these systems or the physiologic changes produced by routine operation of these systems. The objective of this study was to determine the operating characteristics and the physiologic change, produced by short term use of one commercially available thermal control system.

Prototype CoolCup cryolipolysis applicator with over 40% reduced treatment time demonstrates equivalent safety and efficacy with greater patient preference.

PubMed

Kilmer, Suzanne L

2017-01-01

Cryolipolysis is a safe, effective non-surgical procedure to reduce fat. For most cryolipolysis treatments, tissue is pulled between parallel cooling plates with a treatment duration of 60 minutes. A novel contoured cup, medium-sized applicator was developed to increase tissue contact with reduced skin tension and reduced treatment time. This prototype contoured cup was investigated with a standard cryolipolysis applicator to evaluate safety, efficacy, and patient preference. A prototype CoolCup medium-sized vacuum applicator (CoolSculpting System, ZELTIQ Aesthetics) was used to treat n = 19 subjects in the flanks. Randomly assigned, one flank received standard treatment with the CoolCore applicator (-10°C for 60 minutes). The contralateral flank received treatment from the CoolCup (-11°C for 35 minutes). The clinical study primary efficacy endpoint was 70% correct identification of baseline photographs by independent physician review. Incidence of adverse device effects was monitored. Fat layer reduction was measured by ultrasound and subject surveys were administered 12 weeks post-treatment. Equivalent efficacy was demonstrated between the CoolCore standard treatment and the prototype CoolCup. Independent review from three blinded physicians found 81% correct identification of baseline photographs for the standard treatment and 79% for the CoolCup. Ultrasound measurements indicated mean fat layer reduction of 4.38 mm for the standard treatment and 4.40 mm for the CoolCup; no statistically significant difference was found when comparing treatment efficacy of the two applicators (P = 0.96). Patient questionnaires revealed 85% preferred CoolCup because of shorter treatment duration and greater comfort. Procedural assessments revealed 45% lower pain scores for CoolCup. Immediate post-treatment clinical assessments revealed 82% less bruising. Typical side effects, such as numbness and erythema, were similar. There were no adverse events. This clinical study of a prototype medium-sized vacuum applicator with a cooled contoured surface indicates that the CoolCup produces equivalent safety and efficacy to the standard CoolCore cryolipolysis applicator. With a 42% reduction in treatment time, the procedure was found to be more comfortable because of lower vacuum skin tension and shorter treatment duration. Lasers Surg. Med. 49:63-68, 2017. © 2016 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc. © 2016 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Corrosion control when using secondary treated municipal wastewater as alternative makeup water for cooling tower systems.

PubMed

Hsieh, Ming-Kai; Li, Heng; Chien, Shih-Hsiang; Monnell, Jason D; Chowdhury, Indranil; Dzombak, David A; Vidic, Radisav D

2010-12-01

Secondary treated municipal wastewater is a promising alternative to fresh water as power plant cooling water system makeup water, especially in arid regions. Laboratory and field testing was conducted in this study to evaluate the corrosiveness of secondary treated municipal wastewater for various metals and metal alloys in cooling systems. Different corrosion control strategies were evaluated based on varied chemical treatment. Orthophosphate, which is abundant in secondary treated municipal wastewater, contributed to more than 80% precipitative removal of phosphorous-based corrosion inhibitors. Tolyltriazole worked effectively to reduce corrosion of copper (greater than 95% inhibition effectiveness). The corrosion rate of mild steel in the presence of free chlorine 1 mg/L (as Cl2) was approximately 50% higher than in the presence of monochloramine 1 mg/L (as Cl2), indicating that monochloramine is a less corrosive biocide than free chlorine. The scaling layers observed on the metal alloys contributed to corrosion inhibition, which could be seen by comparing the mild steel 21-day average corrosion rate with the last 5-day average corrosion rate, the latter being approximately 50% lower than the former.

Potential Application of a Thermoelectric Generator in Passive Cooling System of Nuclear Power Plants

NASA Astrophysics Data System (ADS)

Wang, Dongqing; Liu, Yu; Jiang, Jin; Pang, Wei; Lau, Woon Ming; Mei, Jun

2017-05-01

In the design of nuclear power plants, various natural circulation passive cooling systems are considered to remove residual heat from the reactor core in the event of a power loss and maintain the plant's safety. These passive systems rely on gravity differences of fluids, resulting from density differentials, rather than using an external power-driven system. Unfortunately, a major drawback of such systems is their weak driving force, which can negatively impact safety. In such systems, there is a temperature difference between the heat source and the heat sink, which potentially offers a natural platform for thermoelectric generator (TEG) applications. While a previous study designed and analyzed a TEG-based passive core cooling system, this paper considers TEG applications in other passive cooling systems of nuclear power plants, after which the concept of a TEG-based passive cooling system is proposed. In such a system, electricity is produced using the system's temperature differences through the TEG, and this electricity is used to further enhance the cooling process.

Solar heating and cooling system design and development

NASA Technical Reports Server (NTRS)

1978-01-01

The development of eight prototype solar heating and combined heating and cooling systems is reported. Manufacture, test, installation, maintenance, problem resolution, and monitoring the operation of prototype systems is included. Heating and cooling equipment for single family residential and commercial applications and eight operational test sites (four heating and four heating and cooling) is described.

78 FR 63516 - Initial Test Program of Emergency Core Cooling Systems for New Boiling-Water Reactors

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-24

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0134] Initial Test Program of Emergency Core Cooling....79.1, ``Initial Test Program of Emergency Core Cooling Systems for New Boiling-Water Reactors.'' This... emergency core cooling systems (ECCSs) for boiling- water reactors (BWRs) whose licenses are issued after...

Cooling System Design for PEM Fuel Cell Powered Air Vehicles

DTIC Science & Technology

2010-06-18

Research Laboratory (NRL) has developed a proton exchange membrane fuel cell ( PEMFC ) powered unmanned air vehicle (UAV) called the Ion Tiger. The Ion Tiger...to design a cooling system for the Ion Tiger and investigate cooling approaches that may be suitable for future PEMFC powered air vehicles. The...modifications) to other PEMFC systems utilizing a CHE for cooling. 18-06-2010 Memorandum Report Unmanned Air Vehicle UAV Fuel cell PEM Cooling Radiator January

BPM System for Electron Cooling in the Fermilab Recycler Ring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joireman, Paul W.; Cai, Jerry; Chase, Brian E.

2004-11-10

We report a VXI based system used to acquire and process BPM data for the electron cooling system in the Fermilab Recycler ring. The BPM system supports acquisition of data from 19 BPM locations in five different sections of the electron cooling apparatus. Beam positions for both electrons and anti-protons can be detected simultaneously with a resolution of {+-}50 {mu}m. We calibrate the system independently for each beam type at each BPM location. We describe the system components, signal processing and modes of operation used in support of the electron-cooling project and present experimental results of system performance for themore » developmental electron cooling installation at Fermilab.« less

Optimization of Cooling Water Flow Rate in Nuclear and Thermal Power Plants Based on a Mathematical Model of Cooling Systems{sup 1}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murav’ev, V. P., E-mail: murval1@mail.ru; Kochetkov, A. V.; Glazova, E. G.

A mathematical model and algorithms are proposed for automatic calculation of the optimum flow rate of cooling water in nuclear and thermal power plants with cooling systems of arbitrary complexity. An unlimited number of configuration and design variants are assumed with the possibility of obtaining a result for any computational time interval, from monthly to hourly. The structural solutions corresponding to an optimum cooling water flow rate can be used for subsequent engineering-economic evaluation of the best cooling system variant. The computerized mathematical model and algorithms make it possible to determine the availability and degree of structural changes for themore » cooling system in all stages of the life cycle of a plant.« less

Ultra-low-vibration pulse-tube cryocooler system - cooling capacity and vibration

NASA Astrophysics Data System (ADS)

Ikushima, Yuki; Li, Rui; Tomaru, Takayuki; Sato, Nobuaki; Suzuki, Toshikazu; Haruyama, Tomiyoshi; Shintomi, Takakazu; Yamamoto, Akira

2008-09-01

This report describes the development of low-vibration cooling systems with pulse-tube (PT) cryocoolers. Generally, PT cryocoolers have the advantage of lower vibrations in comparison to those of GM cryocoolers. However, cooling systems for the cryogenic laser interferometer observatory (CLIO), which is a gravitational wave detector, require an operational vibration that is sufficiently lower than that of a commercial PT cryocooler. The required specification for the vibration amplitude in cold stages is less than ±1 μm. Therefore, during the development of low-vibration cooling systems for the CLIO, we introduced advanced countermeasures for commercial PT cryocoolers. The cooling performance and the vibration amplitude were evaluated. The results revealed that 4 K and 80 K PT cooling systems with a vibration amplitude of less than ±1 μm and cooling performance of 4.5 K and 70 K at heat loads of 0.5 W and 50 W, respectively, were developed successfully.

A Refrigerated Web Camera for Photogrammetric Video Measurement inside Biomass Boilers and Combustion Analysis

PubMed Central

Porteiro, Jacobo; Riveiro, Belén; Granada, Enrique; Armesto, Julia; Eguía, Pablo; Collazo, Joaquín

2011-01-01

This paper describes a prototype instrumentation system for photogrammetric measuring of bed and ash layers, as well as for flying particle detection and pursuit using a single device (CCD) web camera. The system was designed to obtain images of the combustion process in the interior of a domestic boiler. It includes a cooling system, needed because of the high temperatures in the combustion chamber of the boiler. The cooling system was designed using CFD simulations to ensure effectiveness. This method allows more complete and real-time monitoring of the combustion process taking place inside a boiler. The information gained from this system may facilitate the optimisation of boiler processes. PMID:22319349

A refrigerated web camera for photogrammetric video measurement inside biomass boilers and combustion analysis.

PubMed

Porteiro, Jacobo; Riveiro, Belén; Granada, Enrique; Armesto, Julia; Eguía, Pablo; Collazo, Joaquín

2011-01-01

This paper describes a prototype instrumentation system for photogrammetric measuring of bed and ash layers, as well as for flying particle detection and pursuit using a single device (CCD) web camera. The system was designed to obtain images of the combustion process in the interior of a domestic boiler. It includes a cooling system, needed because of the high temperatures in the combustion chamber of the boiler. The cooling system was designed using CFD simulations to ensure effectiveness. This method allows more complete and real-time monitoring of the combustion process taking place inside a boiler. The information gained from this system may facilitate the optimisation of boiler processes.

Next-Generation Evaporative Cooling Systems for the Advanced Extravehicular Mobility Unit Portable Life Support System

NASA Technical Reports Server (NTRS)

Makinen, Janice V.; Anchondo, Ian; Bue, Grant C.; Campbell, Colin; Colunga, Aaron

2012-01-01

The development of the Advanced Extravehicular Mobility Unit (AEMU) Portable Life Support System (PLSS) is currently underway at NASA Johnson Space Center. The AEMU PLSS features two new evaporative cooling systems, the Reduced Volume Prototype Spacesuit Water Membrane Evaporator (RVP SWME), and the Auxiliary Cooling Loop (ACL). The RVP SWME is the third generation of hollow fiber SWME hardware, and like its predecessors, RVP SWME provides nominal crewmember and electronics cooling by flowing water through porous hollow fibers. Water vapor escapes through the hollow fiber pores, thereby cooling the liquid water that remains inside of the fibers. This cooled water is then recirculated to remove heat from the crewmember and PLSS electronics. Major design improvements, including a 36% reduction in volume, reduced weight, and more flight like back-pressure valve, facilitate the packaging of RVP SWME in the AEMU PLSS envelope. In addition to the RVP SWME, the Auxiliary Cooling Loop (ACL), was developed for contingency crewmember cooling. The ACL is a completely redundant, independent cooling system that consists of a small evaporative cooler--the Mini Membrane Evaporator (Mini-ME), independent pump, independent feed-water assembly and independent Liquid Cooling Garment (LCG). The Mini-ME utilizes the same hollow fiber technology featured in the RVP SWME, but is only 25% of the size of RVP SWME, providing only the necessary crewmember cooling in a contingency situation. The ACL provides a number of benefits when compared with the current EMU PLSS contingency cooling technology; contingency crewmember cooling can be provided for a longer period of time, more contingency situations can be accounted for, no reliance on a Secondary Oxygen Vessel (SOV) for contingency cooling--thereby allowing a SOV reduction in size and pressure, and the ACL can be recharged-allowing the AEMU PLSS to be reused, even after a contingency event. The development of these evaporative cooling systems will contribute to a more robust and comprehensive AEMU PLSS.

Passive wall cooling panel with phase change material as a cooling agent

NASA Astrophysics Data System (ADS)

Majid, Masni A.; Tajudin, Rasyidah Ahmad; Salleh, Norhafizah; Hamid, Noor Azlina Abd

2017-11-01

The study was carried out to the determine performance of passive wall cooling panels by using Phase Change Materials as a cooling agent. This passive cooling system used cooling agent as natural energy storage without using any HVAC system. Eight full scale passive wall cooling panels were developed with the size 1500 mm (L) × 500 mm (W) × 100 mm (T). The cooling agent such as glycerine were filled in the tube with horizontal and vertical arrangement. The passive wall cooling panels were casting by using foamed concrete with density between 1200 kg/m3 - 1500 kg/m3. The passive wall cooling panels were tested in a small house and the differences of indoor and outdoor temperature was recorded. Passive wall cooling panels with glycerine as cooling agent in vertical arrangement showed the best performance with dropped of indoor air temperature within 3°C compared to outdoor air temperature. The lowest indoor air temperature recorded was 25°C from passive wall cooling panels with glycerine in vertical arrangement. From this study, the passive wall cooling system could be applied as it was environmental friendly and less maintenance.

Water cooling system for an air-breathing hypersonic test vehicle

NASA Technical Reports Server (NTRS)

Petley, Dennis H.; Dziedzic, William M.

1993-01-01

This study provides concepts for hypersonic experimental scramjet test vehicles which have low cost and low risk. Cryogenic hydrogen is used as the fuel and coolant. Secondary water cooling systems were designed. Three concepts are shown: an all hydrogen cooling system, a secondary open loop water cooled system, and a secondary closed loop water cooled system. The open loop concept uses high pressure helium (15,000 psi) to drive water through the cooling system while maintaining the pressure in the water tank. The water flows through the turbine side of the turbopump to pump hydrogen fuel. The water is then allowed to vent. In the closed loop concept high pressure, room temperature, compressed liquid water is circulated. In flight water pressure is limited to 6000 psi by venting some of the water. Water is circulated through cooling channels via an ejector which uses high pressure gas to drive a water jet. The cooling systems are presented along with finite difference steady-state and transient analysis results. The results from this study indicate that water used as a secondary coolant can be designed to increase experimental test time, produce minimum venting of fluid and reduce overall development cost.

System design package for the solar heating and cooling central data processing system

NASA Technical Reports Server (NTRS)

1978-01-01

The central data processing system provides the resources required to assess the performance of solar heating and cooling systems installed at remote sites. These sites consist of residential, commercial, government, and educational types of buildings, and the solar heating and cooling systems can be hot-water, space heating, cooling, and combinations of these. The instrumentation data associated with these systems will vary according to the application and must be collected, processed, and presented in a form which supports continuity of performance evaluation across all applications. Overall software system requirements were established for use in the central integration facility which transforms raw data collected at remote sites into performance evaluation information for assessing the performance of solar heating and cooling systems.

Applications of the Magnetocaloric Effect in Single-Stage, Multi-Stage and Continuous Adiabatic Demagnetization Refrigerators

NASA Technical Reports Server (NTRS)

Shirron, Peter J.

2014-01-01

Adiabatic demagnetization refrigerators (ADR), based on the magnetocaloric effect, are solid-state coolers that were the first to achieve cooling well into the sub-kelvin regime. Although supplanted by more powerful dilution refrigerators in the 1960s, ADRs have experienced a revival due to the needs of the space community for cooling astronomical instruments and detectors to temperatures below 100 mK. The earliest of these were single-stage refrigerators using superfluid helium as a heat sink. Their modest cooling power (<1 µW at 60 mK[1]) was sufficient for the small (6x6) detector arrays[2], but recent advances in arraying and multiplexing technologies[3] are generating a need for higher cooling power (5-10 µW), and lower temperature (<30 mK). Single-stage ADRs have both practical and fundamental limits to their operating range, as mass grows very rapidly as the operating range is expanded. This has led to the development of new architectures that introduce multi-staging as a way to improve operating range, efficiency and cooling power. Multi-staging also enables ADRs to be configured for continuous operation, which greatly improves cooling power per unit mass. This paper reviews the current field of adiabatic demagnetization refrigeration, beginning with a description of the magnetocaloric effect and its application in single-stage systems, and then describing the challenges and capabilities of multi-stage and continuous ADRs.

Simulation study of air and water cooled photovoltaic panel using ANSYS

NASA Astrophysics Data System (ADS)

Syafiqah, Z.; Amin, N. A. M.; Irwan, Y. M.; Majid, M. S. A.; Aziz, N. A.

2017-10-01

Demand for alternative energy is growing due to decrease of fossil fuels sources. One of the promising and popular renewable energy technology is a photovoltaic (PV) technology. During the actual operation of PV cells, only around 15% of solar irradiance is converted to electricity, while the rest is converted into heat. The electrical efficiency decreases with the increment in PV panel’s temperature. This electrical energy is referring to the open-circuit voltage (Voc), short-circuit current (Isc) and output power generate. This paper examines and discusses the PV panel with water and air cooling system. The air cooling system was installed at the back of PV panel while water cooling system at front surface. The analyses of both cooling systems were done by using ANSYS CFX and PSPICE software. The highest temperature of PV panel without cooling system is 66.3 °C. There is a decrement of 19.2% and 53.2% in temperature with the air and water cooling system applied to PV panel.

Coupling Network Computing Applications in Air-cooled Turbine Blades Optimization

NASA Astrophysics Data System (ADS)

Shi, Liang; Yan, Peigang; Xie, Ming; Han, Wanjin

2018-05-01

Through establishing control parameters from blade outside to inside, the parametric design of air-cooled turbine blade based on airfoil has been implemented. On the basis of fast updating structure features and generating solid model, a complex cooling system has been created. Different flow units are modeled into a complex network topology with parallel and serial connection. Applying one-dimensional flow theory, programs have been composed to get pipeline network physical quantities along flow path, including flow rate, pressure, temperature and other parameters. These inner units parameters set as inner boundary conditions for external flow field calculation program HIT-3D by interpolation, thus to achieve full field thermal coupling simulation. Referring the studies in literatures to verify the effectiveness of pipeline network program and coupling algorithm. After that, on the basis of a modified design, and with the help of iSIGHT-FD, an optimization platform had been established. Through MIGA mechanism, the target of enhancing cooling efficiency has been reached, and the thermal stress has been effectively reduced. Research work in this paper has significance for rapid deploying the cooling structure design.

Cooling tower water conditioning study. [using ozone

NASA Technical Reports Server (NTRS)

Humphrey, M. F.; French, K. R.

1979-01-01

Successful elimination of cooling tower treatment chemicals was demonstrated. Three towers functioned for long periods of time with ozone as the only treatment for the water. The water in the systems was reused as much as 30 times (cycles of concentration) without deleterious effects to the heat exchangers. Actual system blow-down was eliminated and the only makeup water added was that required to replace the evaporation and mist entrainment losses. Minimum water savings alone are approximately 75.1 1/kg/year. Cost estimates indicate that a savings of 55 percent was obtained on the systems using ozone. A major problem experienced in the use of ozone for cooling tower applications was the difficulty of accurate concentration measurements. The ability to control the operational characteristics relies on easily and accurately determined concentration levels. Present methods of detection are subject to inaccuracies because of interfering materials and the rapid destruction of the ozone.

Heat-bath algorithmic cooling with correlated qubit-environment interactions

NASA Astrophysics Data System (ADS)

Rodríguez-Briones, Nayeli A.; Li, Jun; Peng, Xinhua; Mor, Tal; Weinstein, Yossi; Laflamme, Raymond

2017-11-01

Cooling techniques are essential to understand fundamental thermodynamic questions of the low-energy states of physical systems, furthermore they are at the core of practical applications of quantum information science. In quantum computing, this controlled preparation of highly pure quantum states is required from the state initialization of most quantum algorithms to a reliable supply of ancilla qubits that satisfy the fault-tolerance threshold for quantum error correction. Heat-bath algorithmic cooling has been shown to purify qubits by controlled redistribution of entropy and multiple contact with a bath, not only for ensemble implementations but also for technologies with strong but imperfect measurements. In this paper, we show that correlated relaxation processes between the system and environment during rethermalization when we reset hot ancilla qubits, can be exploited to enhance purification. We show that a long standing upper bound on the limits of algorithmic cooling Schulman et al (2005 Phys. Rev. Lett. 94, 120501) can be broken by exploiting these correlations. We introduce a new tool for cooling algorithms, which we call ‘state-reset’, obtained when the coupling to the environment is generalized from individual-qubits relaxation to correlated-qubit relaxation. Furthermore, we present explicit improved cooling algorithms which lead to an increase of purity beyond all the previous work, and relate our results to the Nuclear Overhauser Effect.

Heat loss through the glabrous skin surfaces of heavily insulated, heat-stressed individuals.

PubMed

Grahn, D A; Dillon, J L; Heller, H C

2009-07-01

Insulation reduces heat exchange between a body and the environment. Glabrous (nonhairy) skin surfaces (palms of the hands, soles of the feet, face, and ears) constitute a small percentage of total body surface area but contain specialized vascular structures that facilitate heat loss. We have previously reported that cooling the glabrous skin surfaces is effective in alleviating heat stress and that the application of local subatmospheric pressure enhances the effect. In this paper, we compare the effects of cooling multiple glabrous skin surfaces with and without vacuum on thermal recovery in heavily insulated heat-stressed individuals. Esophageal temperatures (T(es)) and heart rates were monitored throughout the trials. Water loss was determined from pre- and post-trial nude weights. Treadmill exercise (5.6 km/h, 9-16% slope, and 25-45 min duration) in a hot environment (41.5 degrees C, 20-30% relative humidity) while wearing insulating pants and jackets was used to induce heat stress (T(es)>or=39 degrees C). For postexercise recovery, the subjects donned additional insulation (a balaclava, winter gloves, and impermeable boot covers) and rested in the hot environment for 60 min. Postexercise cooling treatments included control (no cooling) or the application of a 10 degrees C closed water circulating system to (a) the hand(s) with or without application of a local subatmospheric pressure, (b) the face, (c) the feet, or (d) multiple glabrous skin regions. Following exercise induction of heat stress in heavily insulated subjects, the rate of recovery of T(es) was 0.4+/-0.2 degrees C/h(n=12), but with application of cooling to one hand, the rate was 0.8+/-0.3 degrees C/h(n=12), and with one hand cooling with subatmospheric pressure, the rate was 1.0+/-0.2 degrees C/h(n=12). Cooling alone yielded two responses, one resembling that of cooling with subatmospheric pressure (n=8) and one resembling that of no cooling (n=4). The effect of treating multiple surfaces was additive (no cooling, DeltaT(es)=-0.4+/-0.2 degrees C; one hand, -0.9+/-0.3 degrees C; face, -1.0+/-0.3 degrees C; two hands, -1.3+/-0.1 degrees C; two feet, -1.3+/-0.3 degrees C; and face, feet, and hands, -1.6+/-0.2 degrees C). Cooling treatments had a similar effect on water loss and final resting heart rate. In heat-stressed resting subjects, cooling the glabrous skin regions was effective in lowering T(es). Under this protocol, the application of local subatmospheric pressure did not significantly increase heat transfer per se but, presumably, increased the likelihood of an effect.

New Help for MS Patients

NASA Technical Reports Server (NTRS)

1993-01-01

The Mark VII MicroClimate Medical Personal Cooling system enables multiple sclerosis' victims, as well as cerebral palsy, spinabifida patients and others to lower their body temperatures. Although this is not a cure, cooling can produce a dramatic improvement in symptoms. The Multiple Sclerosis Association of America has placed cool suits in MS research care centers. This technology originated in the need for cooling systems in spa@esuits. "Cool Suits" are now used by hazardous materials workers, armored vehicle crews, firefighters and crop dusters. A surgical personal cooling system has also been developed for medical personnel working in hot operating room environments.

Effects of anthropogenic heat due to air-conditioning systems on an extreme high temperature event in Hong Kong

NASA Astrophysics Data System (ADS)

Wang, Y.; Li, Y.; Di Sabatino, S.; Martilli, A.; Chan, P. W.

2018-03-01

Anthropogenic heat flux is the heat generated by human activities in the urban canopy layer, which is considered the main contributor to the urban heat island (UHI). The UHI can in turn increase the use and energy consumption of air-conditioning systems. In this study, two effective methods for water-cooling air-conditioning systems in non-domestic areas, including the direct cooling system and central piped cooling towers (CPCTs), are physically based, parameterized, and implemented in a weather research and forecasting model at the city scale of Hong Kong. An extreme high temperature event (June 23-28, 2016) in the urban areas was examined, and we assessed the effects on the surface thermal environment, the interaction of sea-land breeze circulation and urban heat island circulation, boundary layer dynamics, and a possible reduction of energy consumption. The results showed that both water-cooled air-conditioning systems could reduce the 2 m air temperature by around 0.5 °C-0.8 °C during the daytime, and around 1.5 °C around 7:00-8:00 pm when the planetary boundary layer (PBL) height was confined to a few hundred meters. The CPCT contributed around 80%-90% latent heat flux and significantly increased the water vapor mixing ratio in the atmosphere by around 0.29 g kg-1 on average. The implementation of the two alternative air-conditioning systems could modify the heat and momentum of turbulence, which inhibited the evolution of the PBL height (a reduction of 100-150 m), reduced the vertical mixing, presented lower horizontal wind speed and buoyant production of turbulent kinetic energy, and reduced the strength of sea breeze and UHI circulation, which in turn affected the removal of air pollutants. Moreover, the two alternative air-conditioning systems could significantly reduce the energy consumption by around 30% during extreme high temperature events. The results of this study suggest potential UHI mitigation strategies and can be extended to other megacities to enable them to be more resilient to UHI effects.

Improving Durability of Turbine Components Through Trenched Film Cooling and Contoured Endwalls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogard, David G.; Thole, Karen A.

2014-09-30

The experimental and computational studies of the turbine endwall and vane models completed in this research program have provided a comprehensive understanding of turbine cooling with combined film cooling and TBC. To correctly simulate the cooling effects of TBC requires the use of matched Biot number models, a technique developed in our laboratories. This technique allows for the measurement of the overall cooling effectiveness which is a measure of the combined internal and external cooling for a turbine component. The overall cooling effectiveness provides an indication of the actual metal temperature that would occur at engine conditions, and is hencemore » a more powerful performance indicator than the film effectiveness parameter that is commonly used for film cooling studies. Furthermore these studies include the effects of contaminant depositions which are expected to occur when gas turbines are operated with syngas fuels. Results from the endwall studies performed at Penn State University and the vane model studies performed at the University of Texas are the first direct measurements of the combined effects of film cooling and TBC. These results show that TBC has a dominating effect on the overall cooling effectiveness, which enhances the importance of the internal cooling mechanisms, and downplays the importance of the film cooling of the external surface. The TBC was found to increase overall cooling effectiveness by a factor of two to four. When combined with TBC, the primary cooling from film cooling holes was found to be due to the convective cooling within the holes, not from the film effectiveness on the surface of the TBC. Simulations of the deposition of contaminants on the endwall and vane surfaces showed that these depositions caused a large increase in surface roughness and significant degradation of film effectiveness. However, despite these negative factors, the depositions caused only a slight decrease in the overall cooling effectiveness on the endwall, and in some cases a slight increase in overall cooling effectiveness on the vane model. This was attributed to the insulating effects of the depositions which compensated for the negative factors.« less

Advanced Liquid-Cooling Garment Using Highly Thermally Conductive Sheets

NASA Technical Reports Server (NTRS)

Ruemmele, Warren P.; Bue, Grant C.; Orndoff, Evelyne; Tang, Henry

2010-01-01

This design of the liquid-cooling garment for NASA spacesuits allows the suit to remove metabolic heat from the human body more effectively, thereby increasing comfort and performance while reducing system mass. The garment is also more flexible, with fewer restrictions on body motion, and more effectively transfers thermal energy from the crewmember s body to the external cooling unit. This improves the garment s performance in terms of the maximum environment temperature in which it can keep a crewmember comfortable. The garment uses flexible, highly thermally conductive sheet material (such as graphite), coupled with cooling water lines of improved thermal conductivity to transfer the thermal energy from the body to the liquid cooling lines more effectively. The conductive sheets can be layered differently, depending upon the heat loads, in order to provide flexibility, exceptional in-plane heat transfer, and good through-plane heat transfer. A metal foil, most likely aluminum, can be put between the graphite sheets and the external heat source/sink in order to both maximize through-plane heat transfer at the contact points, and to serve as a protection to the highly conductive sheets. Use of a wicking layer draws excess sweat away from the crewmember s skin and the use of an outer elastic fabric ensures good thermal contact of the highly conductive underlayers with the skin. This allows the current state of the art to be improved by having cooling lines that can be more widely spaced to improve suit flexibility and to reduce weight. Also, cooling liquid does not have to be as cold to achieve the same level of cooling. Specific areas on the human body can easily be targeted for greater or lesser cooling to match human physiology, a warmer external environment can be tolerated, and spatial uniformity of the cooling garment can be improved to reduce vasoconstriction limits. Elements of this innovation can be applied to other embodiments to provide effective heat transfer over a flexible and surface-conformable fashion without the limitation of fluid freeze points.

Flow control of an elongated jet in cross-flow: Film cooling effectiveness enhancement using surface dielectric barrier discharge plasma actuator

NASA Astrophysics Data System (ADS)

Audier, P.; Fénot, M.; Bénard, N.; Moreau, E.

2016-02-01

The case presented here deals with plasma flow control applied to a cross-flow configuration, more specifically to a film cooling system. The ability of a plasma dielectric barrier discharge actuator for film cooling effectiveness enhancement is investigated through an experimental set-up, including a film injection from an elongated slot into a thermally uniform cross-flow. Two-dimensional particle image velocimetry and infrared-thermography measurements are performed for three different blowing ratios of M = 0.4, 0.5, and 1. Results show that the effectiveness can be increased when the discharge is switched on, as predicted by the numerical results available in literature. Whatever the blowing ratio, the actuator induces a deflection of the jet flow towards the wall, increases its momentum, and delays its diffusion in the cross-flow.

Effect of propeller slipstream on the drag and performance of the engine cooling system for a general aviation twin-engine aircraft

NASA Technical Reports Server (NTRS)

Katz, J.; Corsiglia, V. R.; Barlow, P. R.

1980-01-01

The pressure recovery of incoming cooling air and the drag associated with engine cooling of a typical general aviation twin-engine aircraft was investigated experimentally. The semispan model was mounted vertically in the 40- by 80-Foot Wind Tunnel at Ames Research Center. The propeller was driven by an electric motor to provide thrust with low vibration levels for the cold-flow configuration. It was found that the propeller slipstream reduces the frontal air spillage around the blunt nacelle shape. Consequently, this slipstream effect promotes flow reattachment at the rear section of the engine nacelle and improves inlet pressure recovery. These effects are most pronounced at high angles of attack, that is, climb condition. For the cruise condition those improvements were more moderate.

Cooling system having reduced mass pin fins for components in a gas turbine engine

DOEpatents

Lee, Ching-Pang; Jiang, Nan; Marra, John J

2014-03-11

A cooling system having one or more pin fins with reduced mass for a gas turbine engine is disclosed. The cooling system may include one or more first surfaces defining at least a portion of the cooling system. The pin fin may extend from the surface defining the cooling system and may have a noncircular cross-section taken generally parallel to the surface and at least part of an outer surface of the cross-section forms at least a quartercircle. A downstream side of the pin fin may have a cavity to reduce mass, thereby creating a more efficient turbine airfoil.

Application of reliability-centered maintenance to boiling water reactor emergency core cooling systems fault-tree analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Y.A.; Feltus, M.A.

1995-07-01

Reliability-centered maintenance (RCM) methods are applied to boiling water reactor plant-specific emergency core cooling system probabilistic risk assessment (PRA) fault trees. The RCM is a technique that is system function-based, for improving a preventive maintenance (PM) program, which is applied on a component basis. Many PM programs are based on time-directed maintenance tasks, while RCM methods focus on component condition-directed maintenance tasks. Stroke time test data for motor-operated valves (MOVs) are used to address three aspects concerning RCM: (a) to determine if MOV stroke time testing was useful as a condition-directed PM task; (b) to determine and compare the plant-specificmore » MOV failure data from a broad RCM philosophy time period compared with a PM period and, also, compared with generic industry MOV failure data; and (c) to determine the effects and impact of the plant-specific MOV failure data on core damage frequency (CDF) and system unavailabilities for these emergency systems. The MOV stroke time test data from four emergency core cooling systems [i.e., high-pressure coolant injection (HPCI), reactor core isolation cooling (RCIC), low-pressure core spray (LPCS), and residual heat removal/low-pressure coolant injection (RHR/LPCI)] were gathered from Philadelphia Electric Company`s Peach Bottom Atomic Power Station Units 2 and 3 between 1980 and 1992. The analyses showed that MOV stroke time testing was not a predictor for eminent failure and should be considered as a go/no-go test. The failure data from the broad RCM philosophy showed an improvement compared with the PM-period failure rates in the emergency core cooling system MOVs. Also, the plant-specific MOV failure rates for both maintenance philosophies were shown to be lower than the generic industry estimates.« less

Effect of human behavior on economizer efficacy and thermal comfort in southern California

NASA Astrophysics Data System (ADS)

Lanning, TIghe Glennon

California has set a zero net-energy conservation goal for the residential sector that is to be achieved by 2020 (California Energy Commission 2011). To reduce energy consumption in the building sector, modern buildings should fundamentally incorporate sustainable performance standards, involving renewable systems, climate-specific strategies, and consideration of a variety of users. Building occupants must operate in concert with the buildings they inhabit in order to maximize the potential of the building, its systems, and their own comfort. In climates with significant diurnal temperature swings, environmental controls designed to capitalize on this should be considered to reduce cooling-related loads. One specific strategy is the air-side economizer, which uses daily outdoor temperature swings to reduce indoor temperature swings. Traditionally a similar effect could be achieved by using thermal mass to buffer indoor temperature swings through thermal lag. Economizers reduce the amount of thermal mass typically required by naturally ventilated buildings. Fans are used to force cool nighttime air deep into the building, allowing lower mass buildings to take advantage of nighttime cooling. Economizers connect to a thermostat, and when the outdoor temperature dips below a programmed set-point the economizer draws cool air from outside, flushing out the warmed interior air. This type of system can be simulated with reasonable accuracy by energy modeling programs; however, because the system is occupant-driven (as opposed to a truly passive mass-driven system) any unpredictable occupant behavior can reduce its effectiveness and create misleading simulation results. This unpredictably has helped prevent the spread of economizers in the residential market. This study investigated to what extent human behavior affected the performance of economizer-based HVAC systems, based on physical observations, environmental data collections, and energy simulations of a residential building in Los Angeles, California. Tangible measures for alleviating problems, such as user-friendly interface design and the incorporation of human behavior into energy models are recommended based on these observations.

High temperature cooling system and method

DOEpatents

Loewen, Eric P.

2006-12-12

A method for cooling a heat source, a method for preventing chemical interaction between a vessel and a cooling composition therein, and a cooling system. The method for cooling employs a containment vessel with an oxidizable interior wall. The interior wall is oxidized to form an oxide barrier layer thereon, the cooling composition is monitored for excess oxidizing agent, and a reducing agent is provided to eliminate excess oxidation. The method for preventing chemical interaction between a vessel and a cooling composition involves introducing a sufficient quantity of a reactant which is reactive with the vessel in order to produce a barrier layer therein that is non-reactive with the cooling composition. The cooling system includes a containment vessel with oxidizing agent and reducing agent delivery conveyances and a monitor of oxidation and reduction states so that proper maintenance of a vessel wall oxidation layer occurs.

Cooling Strategies for Vane Leading Edges in a Syngas Environment Including Effects of Deposition and Turbulence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ames, Forrest; Bons, Jeffrey

2014-09-30

The Department of Energy has goals to move land based gas turbine systems to alternate fuels including coal derived synthetic gas and hydrogen. Coal is the most abundant energy resource in the US and in the world and it is economically advantageous to develop power systems which can use coal. Integrated gasification combined cycles are (IGCC) expected to allow the clean use of coal derived fuels while improving the ability to capture and sequester carbon dioxide. These cycles will need to maintain or increase turbine entry temperatures to develop competitive efficiencies. The use of coal derived syngas introduces a rangemore » of potential contaminants into the hot section of the gas turbine including sulfur, iron, calcium, and various alkali metals. Depending on the effectiveness of the gas clean up processes, there exists significant likelihood that the remaining materials will become molten in the combustion process and potentially deposit on downstream turbine surfaces. Past evidence suggests that deposition will be a strong function of increasing temperature. Currently, even with the best gas cleanup processes a small level of particulate matter in the syngas is expected. Consequently, particulate deposition is expected to be an important consideration in the design of turbine components. The leading edge region of first stage vanes most often have higher deposition rates than other areas due to strong fluid acceleration and streamline curvature in the vicinity of the surface. This region remains one of the most difficult areas in a turbine nozzle to cool due to high inlet temperatures and only a small pressure ratio for cooling. The leading edge of a vane often has relatively high heat transfer coefficients and is often cooled using showerhead film cooling arrays. The throat of the first stage nozzle is another area where deposition potentially has a strongly adverse effect on turbine performance as this region meters the turbine inlet flow. Based on roughness levels found on in service vanes (Bons, et al., 2001, up to 300 microns) flow blockage in first stage turbine nozzles can easily reach 1 to 2 percent in conventional turbines. Deposition levels in syngas fueled gas turbines are expected to be even more problematic. The likelihood of significant deposition to the leading edge of vanes in a syngas environment indicates the need to examine this effect on the leading edge cooling problem. It is critical to understand the influence of leading edge geometry and turbulence on deposition rates for both internally and showerhead cooled leading edge regions. The expected level of deposition in a vane stagnation region not only significantly changes the heat transfer problem but also suggests that cooling arrays may clog. Addressing the cooling issue suggests a need to better understand stagnation region heat transfer with realistic roughness as well as the other variables affecting transport near the leading edge. Also, the question of whether leading edge regions can be cooled internally with modern cooling approaches should also be raised, thus avoiding the clogging issue. Addressing deposition in the pressure side throat region of the nozzle is another critical issue for this environment. Issues such as examining the protective effect of slot and full coverage discrete-hole film cooling on limiting deposition as well as the influence of roughness and turbulence on effectiveness should be raised. The objective of this present study is to address these technical challenges to help enable the development of high efficiency syngas tolerant gas turbine engines.« less

Nonpharmacologic Approach to Minimizing Shivering During Surface Cooling: A Proof of Principle Study1

PubMed Central

Shah, Nirav G.; Cowan, Mark J.; Pickering, Edward; Sareh, Houtan; Afshar, Majid; Fox, Dawn; Marron, Jennifer; Davis, Jennifer; Herold, Keith; Shanholtz, Carl B.; Hasday, Jeffrey D.

2012-01-01

Purpose This study had two objectives: (1) to quantify the metabolic response to physical cooling in febrile patients with Systemic Inflammatory Response Syndrome (SIRS); and (2) to provide proof for the hypothesis that the efficiency of external cooling and the subsequent shivering response are influenced by site and temperature of surface cooling pads. Methods To quantify shivering thermogenesis during surface cooling for fever, we monitored oxygen consumption (VO2) in six febrile patients with SIRS during conventional cooling with cooling blankets and ice packs. To begin to determine how location and temperature of surface cooling influences shivering, we compared 5 cooling protocols for inducing mild hypothermia in six healthy volunteers. Results In the SIRS patients, core temperature decreased 0.67°C per hour, all patients shivered, VO2 increased 57.6% and blood pressure increased 15% during cooling. In healthy subjects, cooling with the 10°C vest was most comfortable and removed heat most efficiently without shivering or VO2 increase. Cooling with combined vest and thigh pads stimulated the most shivering and highest VO2, and increased core temperature. Reducing vest temperature from 10°C to 5°C failed to increase heat removal secondary to cutaneous vasoconstriction. Capsaicin, an agonist for TRPV1 warm-sensing channels, partially reversed this effect in 5 subjects. Conclusions Our results identify the hazards of surface cooling in febrile critically ill patients and support the concept that optimization of cooling pad temperature and position may improve cooling efficiency and reduce shivering. PMID:22762936

Nonpharmacologic approach to minimizing shivering during surface cooling: a proof of principle study.

PubMed

Shah, Nirav G; Cowan, Mark J; Pickering, Edward; Sareh, Houtan; Afshar, Majid; Fox, Dawn; Marron, Jennifer; Davis, Jennifer; Herold, Keith; Shanholtz, Carl B; Hasday, Jeffrey D

2012-12-01

This study had 2 objectives: (1) to quantify the metabolic response to physical cooling in febrile patients with systemic inflammatory response syndrome (SIRS) and (2) to provide proof for the hypothesis that the efficiency of external cooling and the subsequent shivering response are influenced by site and temperature of surface cooling pads. To quantify shivering thermogenesis during surface cooling for fever, we monitored oxygen consumption (VO(2)) in 6 febrile patients with SIRS during conventional cooling with cooling blankets and ice packs. To begin to determine how location and temperature of surface cooling influence shivering, we compared 5 cooling protocols for inducing mild hypothermia in 6 healthy volunteers. In the patients with SIRS, core temperature decreased 0.67 °C per hour, all patients shivered, VO(2) increased 57.6%, and blood pressure increased 15% during cooling. In healthy subjects, cooling with the 10 °C vest was most comfortable and removed heat most efficiently without shivering or VO(2) increase. Cooling with combined vest and thigh pads stimulated the most shivering and highest VO(2) and increased core temperature. Reducing vest temperature from 10 °C to 5 °C failed to increase heat removal secondary to cutaneous vasoconstriction. Capsaicin, an agonist for the transient receptor potential cation channel subfamily V member 1 (TRPV1) warm-sensing channels, partially reversed this effect in 5 subjects. Our results identify the hazards of surface cooling in febrile critically ill patients and support the concept that optimization of cooling pad temperature and position may improve cooling efficiency and reduce shivering. Copyright © 2012 Elsevier Inc. All rights reserved.

Effect of ferrate on green algae removal.

PubMed

Kubiňáková, Emília; Híveš, Ján; Gál, Miroslav; Fašková, Andrea

2017-09-01

Green algae Cladophora aegagropila, present in cooling water of thermal power plants, causes many problems and complications, especially during summer. However, algae and its metabolites are rarely eliminated by common removal methods. In this work, the elimination efficiency of electrochemically prepared potassium ferrate(VI) on algae from cooling water was investigated. The influence of experimental parameters, such as Fe(VI) dosage, application time, pH of the system, temperature and hydrodynamics of the solution on removal efficiency, was optimized. This study demonstrates that algae C. aegagropila can be effectively removed from cooling water by ferrate. Application of ferrate(VI) at the optimized dosage and under the suitable conditions (temperature, pH) leads to 100% removal of green algae Cladophora from the system. Environmentally friendly reduction products (Fe(III)) and coagulation properties favour the application of ferrate for the treatment of water contaminated with studied microorganisms compared to other methods such as chlorination and use of permanganate, where harmful products are produced.

Box-Behnken statistical design to optimize thermal performance of energy storage systems

NASA Astrophysics Data System (ADS)

Jalalian, Iman Joz; Mohammadiun, Mohammad; Moqadam, Hamid Hashemi; Mohammadiun, Hamid

2018-05-01

Latent heat thermal storage (LHTS) is a technology that can help to reduce energy consumption for cooling applications, where the cold is stored in phase change materials (PCMs). In the present study a comprehensive theoretical and experimental investigation is performed on a LHTES system containing RT25 as phase change material (PCM). Process optimization of the experimental conditions (inlet air temperature and velocity and number of slabs) was carried out by means of Box-Behnken design (BBD) of Response surface methodology (RSM). Two parameters (cooling time and COP value) were chosen to be the responses. Both of the responses were significantly influenced by combined effect of inlet air temperature with velocity and number of slabs. Simultaneous optimization was performed on the basis of the desirability function to determine the optimal conditions for the cooling time and COP value. Maximum cooling time (186 min) and COP value (6.04) were found at optimum process conditions i.e. inlet temperature of (32.5), air velocity of (1.98) and slab number of (7).

The Origin of Molecular Clouds in Central Galaxies

NASA Astrophysics Data System (ADS)

Pulido, F. A.; McNamara, B. R.; Edge, A. C.; Hogan, M. T.; Vantyghem, A. N.; Russell, H. R.; Nulsen, P. E. J.; Babyk, I.; Salomé, P.

2018-02-01

We present an analysis of 55 central galaxies in clusters and groups with molecular gas masses and star formation rates lying between {10}8 {and} {10}11 {M}ȯ and 0.5 and 270 {M}ȯ {{yr}}-1, respectively. Molecular gas mass is correlated with star formation rate, Hα line luminosity, and central atmospheric gas density. Molecular gas is detected only when the central cooling time or entropy index of the hot atmosphere falls below ∼1 Gyr or ∼35 keV cm2, respectively, at a (resolved) radius of 10 kpc. These correlations indicate that the molecular gas condensed from hot atmospheres surrounding the central galaxies. We explore the origins of thermally unstable cooling by evaluating whether molecular gas becomes prevalent when the minimum of the cooling to free-fall time ratio ({t}{cool}/{t}{ff}) falls below ∼10. We find that (1) molecular gas-rich systems instead lie between 10< \\min ({t}{cool}/{t}{ff})< 25, where {t}{cool}/{t}{ff}=25 corresponds approximately to cooling time and entropy thresholds of 1 Gyr and 35 {keV} {{cm}}2, respectively; (2) \\min ({t}{cool}/{t}{ff}) is uncorrelated with molecular gas mass and jet power; and (3) the narrow range 10< \\min ({t}{cool}/{t}{ff})< 25 can be explained by an observational selection effect, although a real physical effect cannot be excluded. These results and the absence of isentropic cores in cluster atmospheres are in tension with models that assume thermal instability ensues from linear density perturbations in hot atmospheres when {t}{cool}/{t}{ff}≲ 10. Some of the molecular gas may instead have condensed from atmospheric gas lifted outward by buoyantly rising X-ray bubbles or by dynamically induced uplift (e.g., mergers, sloshing).

Bunch beam cooling

NASA Astrophysics Data System (ADS)

Bryzgunov, M. I.; Kamerdzhiev, V.; Li, J.; Mao, L. J.; Parkhomchuk, V. V.; Reva, V. B.; Yang, X. D.; Zhao, H.

2017-07-01

Electron cooling is used for damping both transverse and longitudinal oscillations of heavy particle. The cooling of bunch ion beam (with RF voltage on) is important part of experiments with inner target, ion collision system, stacking and RF manipulation. The short length of an ion bunch increases the peak luminosity, gives a start-time point for using of the time-of-flight methods and obtains a short extraction beam pulse. This article describes the review of last experiments with electron cooling carried out on the CSRm, CSRe (China) and COSY (Germany) storage rings. The accumulated experience may be used for the project of electron cooler on 2.5 MeV (NICA) and 0.5 MeV HIAF for obtaining high luminosity, depressing beam-beam effects and RF manipulation.

Cool in the kitchen: Radiation, conduction, and the Newton ``hot block'' experiment

NASA Astrophysics Data System (ADS)

Silverman, Mark P.; Silverman, Christopher R.

2000-02-01

Despite frequent reference to Newton's law of cooling in physics and math books, the paper in which Newton reported this law is quite obscure and rarely cited. We have managed to acquire a copy of this paper and discuss the interesting experiment that Newton did in his kitchen. Surprisingly, the paper contains no procedural details or data of any experiments measuring the rate at which a hot object cools. We have performed our own kitchen experiments to investigate the cooling of (a) the burner of an electric range and (b) a block of Styrofoam. Newton's law provides a poor model for both systems, whose th! ! ermal energy loss we can much better understand by examining closely the effects of radiation and conduction.

Evaluation of a liquid cooling garment as a component of the Launch and Entry Suit (LES)

NASA Technical Reports Server (NTRS)

Waligora, J.; Charles, J.; Fritsch, I.; Fortney, S.; Siconolfi, S.; Pepper, L.; Bagian, L.; Kumar, V.

1994-01-01

The LES is a partial pressure suit and a component of the shuttle life support system used during launch and reentry. The LES relies on gas ventilation with cabin air to provide cooling. There are conditions during nominal launch and reentry, landing, and post-landing phases when cabin temperature is elevated. Under these conditions, gas cooling may result in some discomfort and some decrement in orthostatic tolerance. There are emergency conditions involving loss of cabin ECS capability that would challenge crew thermal tolerance. The results of a series of tests are presented. These tests were conducted to assess the effectiveness of a liquid-cooled garment in alleviating thermal discomfort, orthostatic intolerance, and thermal intolerance during simulated mission phases.

Heat exchanger for coal gasification process

DOEpatents

Blasiole, George A.

1984-06-19

This invention provides a heat exchanger, particularly useful for systems requiring cooling of hot particulate solids, such as the separated fines from the product gas of a carbonaceous material gasification system. The invention allows effective cooling of a hot particulate in a particle stream (made up of hot particulate and a gas), using gravity as the motive source of the hot particulate. In a preferred form, the invention substitutes a tube structure for the single wall tube of a heat exchanger. The tube structure comprises a tube with a core disposed within, forming a cavity between the tube and the core, and vanes in the cavity which form a flow path through which the hot particulate falls. The outside of the tube is in contact with the cooling fluid of the heat exchanger.

Air Conditioning with Magnetic Refrigeration : An Efficient, Green Compact Cooling System Using Magnetic Refrigeration

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-09-01

BEETIT Project: Astronautics is developing an air conditioning system that relies on magnetic fields. Typical air conditioners use vapor compression to cool air. Vapor compression uses a liquid refrigerant to circulate within the air conditioner, absorb the heat, and pump the heat out into the external environment. Astronautics’ design uses a novel property of certain materials, called “magnetocaloric materials”, to achieve the same result as liquid refrigerants. These magnetocaloric materials essentially heat up when placed within a magnetic field and cool down when removed, effectively pumping heat out from a cooler to warmer environment. In addition, magnetic refrigeration uses nomore » ozone-depleting gases and is safer to use than conventional air conditioners which are prone to leaks.« less

Liquid-cooled clothing for hot mine rescue work

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-04-01

To prevent exhaustion caused by thermal stress, a rescuer can wear a liquid-cooled hood and vest which absorbs heat, thereby reducing the heat-induced strain on the rescuer's heart and circulatory system. Liquid coolant is continuously circulated through a self-contained system in which the coolant is chilled by a heat sink on the wearer's belt. Cooling duration is approximately 40 minutes when both the hood and vest are worn. Tests were conducted at NASA's Ames Research Center to evaluate the effectiveness of this system. When using the hood and vest with a refrigerated water supply, thermal strain on the wearer wasmore » cut in half and the heart rate was reduced by 30 to 50 beats per minute. Body temperature was significantly lowered, about 0.65/sup 0/C. This system can increase safety for rescue workers who must work in a hot environment, especially when they are not acclimated to high temperaures. Laboratory tests also were conducted using members of a mine rescue team.« less

Cooling system with compressor bleed and ambient air for gas turbine engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsh, Jan H.; Marra, John J.

A cooling system for a turbine engine for directing cooling fluids from a compressor to a turbine blade cooling fluid supply and from an ambient air source to the turbine blade cooling fluid supply to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The cooling system may include a compressor bleed conduit extending from a compressor to the turbine blade cooling fluid supply that provides cooling fluid to at least one turbine blade. The compressor bleed conduit may include an upstream section and a downstream section whereby the upstream section exhausts compressed bleed airmore » through an outlet into the downstream section through which ambient air passes. The outlet of the upstream section may be generally aligned with a flow of ambient air flowing in the downstream section. As such, the compressed air increases the flow of ambient air to the turbine blade cooling fluid supply.« less

Global cooling?

PubMed

Damon, P E; Kunen, S M

1976-08-06

The world's inhabitants, including Scientists, live primarily in the Northern Hemisphere. It is quite natural to be concerned about events that occur close to home and neglect faraway events. Hence, it is not surprising that so little attention has been given to the Southern Hemisphere. Evidence for global cooling has been based, in large part, on a severe cooling trend at high northern latitudes. This article points out that the Northern Hemisphere cooling trend appears to be out of phase with a warming trend at high latitudes in the Southern Hemisphere. The data are scanty. We cannot be sure that these temperature fluctuations are be not the result of natural causes. How it seems most likely that human activity has already significantly perturbed the atmospheric weather system. The effect of particulate matter pollution should be most severe in the highly populated and industrialized Northern Hemisphere. Because of the rapid diffusion of CO(2) molecules within the atmosphere, both hemispheres will be subject to warming due to the atmospheric (greenhouse) effect as the CO(2) content of the atmosphere builds up from the combustion of fossil fuels. Because of the differential effects of the two major sources of atmospheric pollution, the CO(2) greenhouse effect warming trend should first become evident in the Southern Hemisphere. The socioeconomic and political consequences of climate change are profound. We need an early warning system such as would be provided by a more intensive international world weather watch, particularly at high northern and southern latitudes.

How gas cools (or, apples can fall up)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-01-01

This primer on gas cooling systems explains the basics of heat exchange within a refrigeration system, the principle of reverse-cycle refrigeration, and how a gas-engine-driven heat pump can provide cooling, additional winter heating capacity, and hot water year-round. Gas cooling equipment available or under development include natural gas chillers, engine-driven chillers, and absorption chillers. In cogeneration systems, heat recovered from an engine's exhaust and coolant may be used in an absorption chiller to provide air-conditioning. Gas desiccant cooling systems may be used in buildings and businesses that are sensitive to high humidity levels.

A cryogenically cooled, multidetector spectrometer for infrared astronomy

NASA Technical Reports Server (NTRS)

Witteborn, F. C.; Bregman, J. D.

1984-01-01

A liquid helium-cooled, 24 detector grating spectrometer was developed and used for low resolution astronomical observations in the 5 to 14 micron spectral range. The instrument operated on the 91 cm Kuiper Airborne Observatory, the 3 m IRTF (Mauna Kea), the 3 m Shane telescope Observatory, the 3 m Shane telescope (Lick Observatory), and the 152 cm NASA and University of Arizona telescope. The detectors are discrete Si:Bi photoconductors with individual metal oxide semiconductor field effect transistor preamplifiers operating at 4 K. The system uses a liquid helium-cooled slit, order-sorter filter, collimator mirror, grating, and camera mirror arranged in a Czerny-Turner configuration with a cold stop added between the collimator mirror and the grating. The distances between components are chosen so that the collimator mirror images the secondary mirror of the telescope onto the cold stop, thus providing a very effective baffle. Scattered radiation is effectively reduced by using liquid helium-cooled, black baffles to divide the spectrometer into three separate compartments. The system noise-equivalent flux density, when used on the 152 cm telescope from 8 to 13 microns with a resolving power of 50, is 4.4 x 10 to the minus 17th power W/sq cm micron square root of Hz. The main applications are for measuring continuum radiation levels and solid state emission and absorption features in regions of star and planet formation.

Focal epidural cooling reduces the infarction volume of permanent middle cerebral artery occlusion in swine.

PubMed

Zhang, Lihua; Cheng, Huilin; Shi, Jixin; Chen, Jun

2007-02-01

The protective effect against ischemic stroke by systemic hypothermia is limited by the cooling rate and it has severe complications. This study was designed to evaluate the effect of SBH induced by epidural cooling on infarction volume in a swine model of PMCAO. Permanent middle cerebral artery occlusion was performed in 12 domestic swine assigned to groups A and B. In group A, the cranial and rectal temperatures were maintained at normal range (37 degrees C-39 degrees C) for 6 hours after PMCAO. In group B, cranial temperature was reduced to moderate (deep brain, <30 degrees C) and deep (brain surface, <20 degrees C) temperature and maintained at that level for 5 hours after 1 hour after PMCAO, by the epidural cooling method. All animals were euthanized 6 hours after MCAO; their brains were sectioned and stained with 2,3,5-triphenyltetrazolium chloride and their infarct volumes were calculated. The moderate and deep brain temperature (at deep brain and brain surface) can be induced by rapid epidural cooling, whereas the rectal temperature was maintained within normal range. The infarction volume after PMCAO was significantly reduced by epidural cooling compared with controls (13.73% +/- 1.82% vs 5.62% +/- 2.57%, P < .05). The present study has demonstrated, with histologic confirmation, that epidural cooling may be a useful strategy for reducing infarct volume after the onset of ischemia.

Investment appraisal of technology innovations on dairy farm electricity consumption.

PubMed

Upton, J; Murphy, M; De Boer, I J M; Groot Koerkamp, P W G; Berentsen, P B M; Shalloo, L

2015-02-01

The aim of this study was to conduct an investment appraisal for milk-cooling, water-heating, and milk-harvesting technologies on a range of farm sizes in 2 different electricity-pricing environments. This was achieved by using a model for electricity consumption on dairy farms. The model simulated the effect of 6 technology investment scenarios on the electricity consumption and electricity costs of the 3 largest electricity-consuming systems within the dairy farm (i.e., milk-cooling, water-heating, and milking machine systems). The technology investment scenarios were direct expansion milk-cooling, ice bank milk-cooling, milk precooling, solar water-heating, and variable speed drive vacuum pump-milking systems. A dairy farm profitability calculator was combined with the electricity consumption model to assess the effect of each investment scenario on the total discounted net income over a 10-yr period subsequent to the investment taking place. Included in the calculation were the initial investments, which were depreciated to zero over the 10-yr period. The return on additional investment for 5 investment scenarios compared with a base scenario was computed as the investment appraisal metric. The results of this study showed that the highest return on investment figures were realized by using a direct expansion milk-cooling system with precooling of milk to 15°C with water before milk entry to the storage tank, heating water with an electrical water-heating system, and using standard vacuum pump control on the milking system. Return on investment figures did not exceed the suggested hurdle rate of 10% for any of the ice bank scenarios, making the ice bank system reliant on a grant aid framework to reduce the initial capital investment and improve the return on investment. The solar water-heating and variable speed drive vacuum pump scenarios failed to produce positive return on investment figures on any of the 3 farm sizes considered on either the day and night tariff or the flat tariff, even when the technology costs were reduced by 40% in a sensitivity analysis of technology costs. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Temperature profiles of different cooling methods in porcine pancreas procurement.

PubMed

Weegman, Bradley P; Suszynski, Thomas M; Scott, William E; Ferrer Fábrega, Joana; Avgoustiniatos, Efstathios S; Anazawa, Takayuki; O'Brien, Timothy D; Rizzari, Michael D; Karatzas, Theodore; Jie, Tun; Sutherland, David E R; Hering, Bernhard J; Papas, Klearchos K

2014-01-01

Porcine islet xenotransplantation is a promising alternative to human islet allotransplantation. Porcine pancreas cooling needs to be optimized to reduce the warm ischemia time (WIT) following donation after cardiac death, which is associated with poorer islet isolation outcomes. This study examines the effect of four different cooling Methods on core porcine pancreas temperature (n = 24) and histopathology (n = 16). All Methods involved surface cooling with crushed ice and chilled irrigation. Method A, which is the standard for porcine pancreas procurement, used only surface cooling. Method B involved an intravascular flush with cold solution through the pancreas arterial system. Method C involved an intraductal infusion with cold solution through the major pancreatic duct, and Method D combined all three cooling Methods. Surface cooling alone (Method A) gradually decreased core pancreas temperature to <10 °C after 30 min. Using an intravascular flush (Method B) improved cooling during the entire duration of procurement, but incorporating an intraductal infusion (Method C) rapidly reduced core temperature 15-20 °C within the first 2 min of cooling. Combining all methods (Method D) was the most effective at rapidly reducing temperature and providing sustained cooling throughout the duration of procurement, although the recorded WIT was not different between Methods (P = 0.36). Histological scores were different between the cooling Methods (P = 0.02) and the worst with Method A. There were differences in histological scores between Methods A and C (P = 0.02) and Methods A and D (P = 0.02), but not between Methods C and D (P = 0.95), which may highlight the importance of early cooling using an intraductal infusion. In conclusion, surface cooling alone cannot rapidly cool large (porcine or human) pancreata. Additional cooling with an intravascular flush and intraductal infusion results in improved core porcine pancreas temperature profiles during procurement and histopathology scores. These data may also have implications on human pancreas procurement as use of an intraductal infusion is not common practice. © 2014 John Wiley & Sons A/S Published by John Wiley & Sons Ltd.

Demonstration of an efficient cooling approach for SBIRS-Low

NASA Astrophysics Data System (ADS)

Nieczkoski, S. J.; Myers, E. A.

2002-05-01

The Space Based Infrared System-Low (SBIRS-Low) segment is a near-term Air Force program for developing and deploying a constellation of low-earth orbiting observation satellites with gimbaled optics cooled to cryogenic temperatures. The optical system design and requirements present unique challenges that make conventional cooling approaches both complicated and risky. The Cryocooler Interface System (CIS) provides a remote, efficient, and interference-free means of cooling the SBIRS-Low optics. Technology Applications Inc. (TAI), through a two-phase Small Business Innovative Research (SBIR) program with Air Force Research Laboratory (AFRL), has taken the CIS from initial concept feasibility through the design, build, and test of a prototype system. This paper presents the development and demonstration testing of the prototype CIS. Prototype system testing has demonstrated the high efficiency of this cooling approach, making it an attractive option for SBIRS-Low and other sensitive optical and detector systems that require low-impact cryogenic cooling.

Viscoelastic finite element analysis of residual stresses in porcelain-veneered zirconia dental crowns.

PubMed

Kim, Jeongho; Dhital, Sukirti; Zhivago, Paul; Kaizer, Marina R; Zhang, Yu

2018-06-01

The main problem of porcelain-veneered zirconia (PVZ) dental restorations is chipping and delamination of veneering porcelain owing to the development of deleterious residual stresses during the cooling phase of veneer firing. The aim of this study is to elucidate the effects of cooling rate, thermal contraction coefficient and elastic modulus on residual stresses developed in PVZ dental crowns using viscoelastic finite element methods (VFEM). A three-dimensional VFEM model has been developed to predict residual stresses in PVZ structures using ABAQUS finite element software and user subroutines. First, the newly established model was validated with experimentally measured residual stress profiles using Vickers indentation on flat PVZ specimens. An excellent agreement between the model prediction and experimental data was found. Then, the model was used to predict residual stresses in more complex anatomically-correct crown systems. Two PVZ crown systems with different thermal contraction coefficients and porcelain moduli were studied: VM9/Y-TZP and LAVA/Y-TZP. A sequential dual-step finite element analysis was performed: heat transfer analysis and viscoelastic stress analysis. Controlled and bench convection cooling rates were simulated by applying different convective heat transfer coefficients 1.7E-5 W/mm 2 °C (controlled cooling) and 0.6E-4 W/mm 2 °C (bench cooling) on the crown surfaces exposed to the air. Rigorous viscoelastic finite element analysis revealed that controlled cooling results in lower maximum stresses in both veneer and core layers for the two PVZ systems relative to bench cooling. Better compatibility of thermal contraction coefficients between porcelain and zirconia and a lower porcelain modulus reduce residual stresses in both layers. Copyright © 2018 Elsevier Ltd. All rights reserved.

The influence of local effects on thermal sensation under non-uniform environmental conditions--gender differences in thermophysiology, thermal comfort and productivity during convective and radiant cooling.

PubMed

Schellen, L; Loomans, M G L C; de Wit, M H; Olesen, B W; van Marken Lichtenbelt, W D

2012-09-10

Applying high temperature cooling concepts, i.e. high temperature cooling (T(supply) is 16-20°C) HVAC systems, in the built environment allows the reduction in the use of (high quality) energy. However, application of high temperature cooling systems can result in whole body and local discomfort of the occupants. Non-uniform thermal conditions, which may occur due to application of high temperature cooling systems, can be responsible for discomfort. Contradictions in literature exist regarding the validity of the often used predicted mean vote (PMV) index for both genders, and the index is not intended for evaluating the discomfort due to non-uniform environmental conditions. In some cases, however, combinations of local and general discomfort factors, for example draught under warm conditions, may not be uncomfortable. The objective of this study was to investigate gender differences in thermophysiology, thermal comfort and productivity in response to thermal non-uniform environmental conditions. Twenty healthy subjects (10 males and 10 females, age 20-29 years) were exposed to two different experimental conditions: a convective cooling situation (CC) and a radiant cooling situation (RC). During the experiments physiological responses, thermal comfort and productivity were measured. The results show that under both experimental conditions the actual mean thermal sensation votes significantly differ from the PMV-index; the subjects are feeling colder than predicted. Furthermore, the females are more uncomfortable and dissatisfied compared to the males. For females, the local sensations and skin temperatures of the extremities have a significant influence on whole body thermal sensation and are therefore important to consider under non-uniform environmental conditions. Copyright © 2012 Elsevier Inc. All rights reserved.

Seminar 14 - Desiccant Enhanced Air Conditioning: Desiccant Enhanced Evaporative Air Conditioning (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozubal, E.

2013-02-01

This presentation explains how liquid desiccant based coupled with an indirect evaporative cooler can efficiently produce cool, dry air, and how a liquid desiccant membrane air conditioner can efficiently provide cooling and dehumidification without the carryover problems of previous generations of liquid desiccant systems. It provides an overview to a liquid desiccant DX air conditioner that can efficiently provide cooling and dehumidification to high latent loads without the need for reheat, explains how liquid desiccant cooling and dehumidification systems can outperform vapor compression based air conditioning systems in hot and humid climates, explains how liquid desiccant cooling and dehumidification systemsmore » work, and describes a refrigerant free liquid desiccant based cooling system.« less

Impact of cool-down conditions at Tc on the superconducting rf cavity quality factor

NASA Astrophysics Data System (ADS)

Vogt, J.-M.; Kugeler, O.; Knobloch, J.

2013-10-01

Many next-generation, high-gradient accelerator applications, from energy-recovery linacs to accelerator-driven systems (ADS) rely on continuous wave (CW) operation for which superconducting radio-frequency (SRF) systems are the enabling technology. However, while SRF cavities dissipate little power, they must be cooled by liquid helium and for many CW accelerators the complexity as well as the investment and operating costs of the cryoplant can prove to be prohibitive. We investigated ways to reduce the dynamic losses by improving the residual resistance (Rres) of niobium cavities. Both the material treatment and the magnetic shielding are known to have an impact. In addition, we found that Rres can be reduced significantly when the cool-down conditions during the superconducting phase transition of the niobium are optimized. We believe that not only do the cool-down conditions impact the level to which external magnetic flux is trapped in the cavity but also that thermoelectric currents are generated which in turn create additional flux that can be trapped. Therefore, we investigated the generation of flux and the dynamics of flux trapping and release in a simple model niobium-titanium system that mimics an SRF cavity in its helium tank. We indeed found that thermal gradients along the system during the superconducting transition can generate a thermoelectric current and magnetic flux, which subsequently can be trapped. These effects may explain the observed variation of the cavity’s Rres with cool-down conditions.

Sport fishery potential of power plant cooling ponds: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heidinger, R.C.; Lewis, W.M.

1986-10-01

This research was undertaken to determine if cooling ponds could serve as habitat for several coolwater fish species and also to evaluate the potential use of cooling ponds as nursery areas for receiving waters. The work was conducted on two cooling ponds in northern Illinois. Walleye (Stizostedion vitreum), muskellunge (Esox masquinongy), striped bass (Morone saxatilis) fingerlings, and adult threadfin shad (Dorosoma petenense) were stocked into both cooling ponds. The hybrids between the striped bass and white bass (M. chrysops) had been previously stocked into Collins Pond. Smallmouth bass (Micropterus dolomieui) fingerlings and larval striped bass and walleye were stocked inmore » Dresden Pond. Several sampling techniques including seining, electrofishing, and rotenoning were used to monitor growth and survival of stocked species. In addition, escapement of stocked and indigenous species was monitored at the Dresden Pond spillway. Walleye, muskellunge, striped bass and hybrid striped bass exhibited excellent growth in Collins Pond as did smallmouth bass in Dresden Pond. One of the primary differences between an open system (such as Dresden Pond) and a closed system (such as Collins Pond) is the potential that the open system has to serve as a fish nursery area for receiving waters. The stocking of ''coolwater'' species in a closed type system such as Collins Pond is an effective way to control and maintain selected sport species. Dresden Pond was not open to public fishing during this study, but Collins Pond developed an excellent sport fishery as a result of these stockings.« less

Effect of local cooling on short-term, intense exercise.

PubMed

Kwon, Young S; Robergs, Robert A; Schneider, Suzanne M

2013-07-01

The widespread belief that local cooling impairs short-term, strenuous exercise performance is controversial. Eighteen original investigations involving cooling before and intermittent cooling during short-term, intensive exercise are summarized in this review. Previous literature examining short-term intensive exercise and local cooling primarily has been limited to the effects on muscle performance immediately or within minutes following cold application. Most previous cooling studies used equal and longer than 10 minutes of pre-cooling, and found that cooling reduced strength, performance and endurance. Because short duration, high intensity exercise requires adequate warm-up to prepare for optimal performance, prolonged pre-cooling is not an effective method to prepare for this type of exercise. The literature related to the effect of acute local cooling immediately before short duration, high intensity isotonic exercise such as weight lifting is limited. However, local intermittent cooling during short-term, high intense exercise may provide possible beneficial effects; first, by pain reduction, caused by an "irritation effect" from hand thermal receptors which block pain sensation, or second, by a cooling effect, whereby stimulation of hand thermal receptors or a slight lowering of blood temperature might alter central fatigue.

Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moisseytsev, A.; Sienicki, J. J.; Lv, Q.

Modeling for commercially available and cost effective dry air coolers such as those manufactured by Harsco Industries has been implemented in the Argonne National Laboratory Plant Dynamics Code for system level dynamic analysis of supercritical carbon dioxide (sCO 2) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO 2 Brayton cycles with dry air cooling whereby heat is rejected directly to the atmospheric heat sink without the need for cooling towers that require makeup water for evaporative losses. It has sometimes been stated that a benefit of the sCO 2 Brayton cycle is that it enablesmore » dry air cooling implying that the Rankine steam cycle does not. A preliminary and simple examination of a Rankine superheated steam cycle and an air-cooled condenser indicates that dry air cooling can be utilized with both cycles provided that the cycle conditions are selected appropriately« less

Effect of hypersaline cooling canals on aquifer salinization

USGS Publications Warehouse

Hughes, Joseph D.; Langevin, Christian D.; Brakefield-Goswami, Linzy

2010-01-01

The combined effect of salinity and temperature on density-driven convection was evaluated in this study for a large (28 km2) cooling canal system (CCS) at a thermoelectric power plant in south Florida, USA. A two-dimensional cross-section model was used to evaluate the effects of hydraulic heterogeneities, cooling canal salinity, heat transport, and cooling canal geometry on aquifer salinization and movement of the freshwater/saltwater interface. Four different hydraulic conductivity configurations, with values ranging over several orders of magnitude, were evaluated with the model. For all of the conditions evaluated, aquifer salinization was initiated by the formation of dense, hypersaline fingers that descended downward to the bottom of the 30-m thick aquifer. Saline fingers reached the aquifer bottom in times ranging from a few days to approximately 5 years for the lowest hydraulic conductivity case. Aquifer salinization continued after saline fingers reached the aquifer bottom and coalesced by lateral movement away from the site. Model results showed that aquifer salinization was most sensitive to aquifer heterogeneity, but was also sensitive to CCS salinity, temperature, and configuration.

Thermal modeling in an engine cooling system to control coolant flow for fuel consumption improvement

NASA Astrophysics Data System (ADS)

Park, Sangki; Woo, Seungchul; Kim, Minho; Lee, Kihyung

2017-04-01

The design and evaluation of engine cooling and lubrication systems is generally based on real vehicle tests. Our goal here was to establish an engine heat balance model based on mathematical and interpretive analysis of each element of a passenger diesel engine cooling system using a 1-D numerical model. The purpose of this model is to determine ways of optimizing the cooling and lubrication components of an engine and then to apply these methods to actual cooling and lubrication systems of engines that will be developed in the future. Our model was operated under the New European Driving Cycle (NEDC) mode conditions, which represent the fuel economy evaluation mode in Europe. The flow rate of the cooling system was controlled using a control valve. Our results showed that the fuel efficiency was improved by as much as 1.23 %, cooling loss by 1.35 %, and friction loss by 2.21 % throughout NEDC modes by modification of control conditions.

Small Scale Solar Cooling Unit in Climate Conditions of Latvia: Environmental and Economical Aspects

NASA Astrophysics Data System (ADS)

Jaunzems, Dzintars; Veidenbergs, Ivars

2010-01-01

The paper contributes to the analyses from the environmental and economical point of view of small scale solar cooling system in climate conditions of Latvia. Cost analyses show that buildings with a higher cooling load and full load hours have lower costs. For high internal gains, cooling costs are around 1,7 €/kWh and 2,5 €/kWh for buildings with lower internal gains. Despite the fact that solar cooling systems have significant potential to reduce CO2 emissions due to a reduction of electricity consumption, the economic feasibility and attractiveness of solar cooling system is still low.

Asetek's Warm-Water Liquid Cooling System Yields Energy Cost Savings at

Science.gov Websites

NREL | Energy Systems Integration Facility | NREL Asetek Asetek's Warm-Water Liquid Cooling System Yields Energy Cost Savings at NREL Asetek's RackCDU liquid cooling system was installed and tested at the Energy Systems Integration Facility's (ESIF's) ultra-energy-efficient high-performance

The impact of the Morgantown power plant on the Potomac estuary: an interpretive summary of the 1972-1973 investigations. Final interpretive report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bongers, L.H.; Polgar, T.T.; Lippson, A.J.

1975-12-01

This report summarizes and interprets the findings of aquatic field studies conducted at PEPCO's Morgantown generating station. The purpose of this investigation was to determine if power plant operations would adversely affect the aquatic ecosystem of the Potomac River. The field studies, conducted in 1972 and 1973, include investigations of physical effects and of biological responses to heat, chlorination, and passage through the plants cooling system. Key cooling system operation characteristics were systematically varied while measurements were conducted. On the basis of these entrainment and site investigations, it was possible to arrive at value judgments on the significance of observedmore » plant effects. Both impingement and entrainment effects were considered in these studies.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Qu, Ming; Sun, Xiao-Guang

Separate sensible and latent cooling systems offer superior energy efficiency performance compared to conventional vapor compression air conditioning systems. In this paper we describe an innovative non-vapor compression system that uses electrochemical compressor (ECC) to pump hydrogen between 2-metal hydride reservoirs to provide the sensible cooling effect. The heat rejected during this process is used to regenerate the ionic liquid (IL) used for desiccant dehumidification. The overall system design is illustrated. The Xergy version 4C electrochemical compressor, while not designed as a high pressure system, develops in excess of 2 MPa (300 psia) and pressure ratios > 30. The projectedmore » base efficiency improvement of the electrochemical compressor is expected to be ~ 20% with higher efficiency when in low capacity mode due to being throttleable to lower capacity with improved efficiency. The IL was tailored to maximize the absorption/desorption rate of water vapor at moderate regeneration temperature. This IL, namely, [EMIm].OAc, is a hydrophilic IL with a working concentration range of 28.98% when operating between 25 75 C. The ECC metal hydride system is expected to show superior performance to typical vapor compression systems. As such, the combined efficiency gains from the use of ECC and separate and sensible cooling would offer significant potential savings to existing vapor compression cooling technology. A high efficiency Window Air Conditioner system is described based on this novel configuration. The system s schematic is provided. Models compared well with actual operating data obtained by running the prototype system. Finally, a model of an LiCl desiccant system in conjunction with the ECC-based metal hydride heat exchangers is provided.« less

Role of bacterial adhesion in the microbial ecology of biofilms in cooling tower systems.

PubMed

Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P; Packman, Aaron

2009-01-01

The fate of the three heterotrophic biofilm forming bacteria, Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. in pilot scale cooling towers was evaluated both by observing the persistence of each species in the recirculating water and the formation of biofilms on steel coupons placed in each cooling tower water reservoir. Two different cooling tower experiments were performed: a short-term study (6 days) to observe the initial bacterial colonization of the cooling tower, and a long-term study (3 months) to observe the ecological dynamics with repeated introduction of the test strains. An additional set of batch experiments (6 days) was carried out to evaluate the adhesion of each strain to steel surfaces under similar conditions to those found in the cooling tower experiments. Substantial differences were observed in the microbial communities that developed in the batch systems and cooling towers. P. aeruginosa showed a low degree of adherence to steel surfaces both in batch and in the cooling towers, but grew much faster than K. pneumoniae and Flavobacterium in mixed-species biofilms and ultimately became the dominant organism in the closed batch systems. However, the low degree of adherence caused P. aeruginosa to be rapidly washed out of the open cooling tower systems, and Flavobacterium became the dominant microorganism in the cooling towers in both the short-term and long-term experiments. These results indicate that adhesion, retention and growth on solid surfaces play important roles in the bacterial community that develops in cooling tower systems.

Role of bacterial adhesion in the microbial ecology of biofilms in cooling tower systems

PubMed Central

Liu, Yang; Zhang, Wei; Sileika, Tadas; Warta, Richard; Cianciotto, Nicholas P.; Packman, Aaron

2009-01-01

The fate of the three heterotrophic biofilm forming bacteria, Pseudomonas aeruginosa, Klebsiella pneumoniae and Flavobacterium sp. in pilot scale cooling towers was evaluated both by observing the persistence of each species in the recirculating water and the formation of biofilms on steel coupons placed in each cooling tower water reservoir. Two different cooling tower experiments were performed: a short-term study (6 days) to observe the initial bacterial colonization of the cooling tower, and a long-term study (3 months) to observe the ecological dynamics with repeated introduction of the test strains. An additional set of batch experiments (6 days) was carried out to evaluate the adhesion of each strain to steel surfaces under similar conditions to those found in the cooling tower experiments. Substantial differences were observed in the microbial communities that developed in the batch systems and cooling towers. P. aeruginosa showed a low degree of adherence to steel surfaces both in batch and in the cooling towers, but grew much faster than K. pneumoniae and Flavobacterium in mixed-species biofilms and ultimately became the dominant organism in the closed batch systems. However, the low degree of adherence caused P. aeruginosa to be rapidly washed out of the open cooling tower systems, and Flavobacterium became the dominant microorganism in the cooling towers in both the short-term and long-term experiments. These results indicate that adhesion, retention and growth on solid surfaces play important roles in the bacterial community that develops in cooling tower systems. PMID:19177226

Achieving more reliable operation of turbine generators at nuclear power plants by improving the water chemistry of the generator stator cooling system

NASA Astrophysics Data System (ADS)

Tyapkov, V. F.; Chudakova, I. Yu.; Alekseenko, O. A.

2011-08-01

Ways of improving the water chemistry used in the turbine generator stator's cooling systems at Russian nuclear power plants are considered. Data obtained from operational chemical monitoring of indicators characterizing the quality of cooling water in the turbine generator stator cooling systems of operating power units at nuclear power plants are presented.

Beneficial effects of groundwater entry into liquid-dominated geothermal systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lippmann, M.J.; Truesdell, A.H.

In all active liquid-dominated geothermal systems there is continuous circulation of mass and transfer of heat, otherwise they would slowly cool and fade away. In the natural state these systems are in dynamic equilibrium with the surrounding colder groundwater aquifers. The ascending geothermal fluids cool conductively, boil, or mix with groundwaters, and ultimately may discharge at the surface as fumaroles or hot springs. With the start of fluid production and the lowering of reservoir pressure, the natural equilibrium is disrupted and cooler groundwater tends to enter the reservoir. Improperly constructed or damaged wells, and wells located near the margins ofmore » the geothermal system, exhibit temperature reductions (and possibly scaling from mixing of chemically distinct fluids) as the cooler-water moves into the reservoir. These negative effects, especially in peripheral wells are, however, compensated by the maintenance of reservoir pressure and a reduction in reservoir boiling that might result in mineral precipitation in the formation pores and fractures. The positive effect of cold groundwater entry on the behavior of liquid-dominated system is illustrated by using simple reservoir models. The simulation results show that even though groundwater influx into the reservoir causes cooling of fluids produced from wells located near the cold-water recharge area, it also reduces pressure drawdown and boiling in the exploited zone, and sweeps the heat stored in the reservoir rocks toward production wells, thus increasing the productive life of the wells and field. 9 refs.« less

Legionella species colonization in cooling towers: risk factors and assessment of control measures.

PubMed

Mouchtouri, Varvara A; Goutziana, Georgia; Kremastinou, Jenny; Hadjichristodoulou, Christos

2010-02-01

Cooling towers can be colonized by Legionella spp, and inhalation of aerosols generated by their operation may cause Legionnaires' disease in susceptible hosts. Environmental investigations of Legionnaires' disease outbreaks linked with cooling towers have revealed poorly maintained systems, lack of control measures, and failure of system equipment. The purpose of this study was to identify Legionella-contaminated cooling towers, identify risk factors for contamination, and assess the effectiveness of control measures. A total of 96 cooling towers of public buildings were registered and inspected, and 130 samples were collected and microbiologically tested. Microbiological test results were associated with characteristics of cooling towers, water samples, inspection results, and maintenance practices. Of the total 96 cooling towers examined, 47 (48.9%) were colonized by Legionella spp, and 22 (22.9%) required remedial action. A total of 65 samples (50.0%) were positive (> or = 500 cfu L(-1)), and 30 (23%) were heavily contaminated (> or = 10(4) cfu L(-1)). Of the 69 isolates identified, 55 strains (79.7.%) were L pneumophila. Legionella colonization was positively associated with the absence of training on Legionella control (relative risk [RR] = 1.66; P = .02), absence of regular Legionella testing (RR = 2.07: P = .002), absence of sunlight protection (RR = 1.63: P = .02), with samples in which the free residual chlorine level in the water sample was < 0.5 mg/L (RR = 2.23; P = .01), and with total plate count (P =.001). Colonization was negatively associated with chemical disinfection (RR = 0.2; P = .0003) and with the presence of a risk assessment and management plan (RR = 0.12; P = .0005). A statistically significant higher age (P =.01) was found in legionellae-positive cooling towers (median, 17 years; interquartile range [IQR] =5.0 to 26.0 years) compared with noncolonized cooling towers (median age, 6 years; IQR =1.0 to 13.5 years). After the 22 legionellae-positive cooling towers were disinfected with chlorine, 2 (9%) of them remained positive for Legionella spp with a concentration > or = 1000 cfu L(-1). Cooling towers can be heavily colonized by Legionella spp and thus present a potential risk for infection. This study demonstrates the importance of a risk assessment and management plan. Water chlorination effectively reduces legionellae contamination. Proper training of cooling tower operators is paramount. Copyright 2010 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Simulations Of Laser Cooling In An Ultracold Neutral Plasma

NASA Astrophysics Data System (ADS)

Langin, Thomas; Strickler, Trevor; Pohl, Thomas; Vrinceanu, Daniel; Killian, Thomas

2016-05-01

Ultracold neutral plasmas (UNPs) generated by photoionization of laser-cooled, magneto-optically trapped neutral gases, are useful systems for studying strongly coupled plasmas. Coupling is parameterized by Γi, the ratio of the average nearest neighbor Coulomb interaction energy to the ion kinetic energy. For typical UNPs, Γi is currently limited to ~ 3 . For alkaline earth ions, higher Γi can be achieved by laser-cooling. Using Molecular Dynamics and a quantum trajectories approach, we have simulated laser-cooling of Sr+ ions interacting through a Yukawa potential. The simulations include re-pumping from two long-lived D-states, and are conducted at experimentally achievable parameters (density n = 2 e+14 m-3, size σ0 = 4 mm, Te = 19 K). Laser-cooling is shown to both reduce the temperature by a factor of 2 over relevant timescales (tens of μ s) and slow the electron thermal-pressure driven radial expansion of the UNP. We also discuss the unique aspects of laser-cooling in a highly collisional system; in particular, the effect of collisions on dark state formation due to the coupling of the P3/2 state to both the S1/2 (via the cooling transition) and the D5/2 (via a re-pump transition) states. Supported by NSF and DoE, the Air Force Office of Scientific Research, the NDSEG Program, and NIH NCRR S10RR02950, an IBM SUR Award in partnership with CISCO, Qlogic and Adaptive Computing.

Optimization analysis of the motor cooling method in semi-closed single screw refrigeration compressor

NASA Astrophysics Data System (ADS)

Wang, Z. L.; Shen, Y. F.; Wang, Z. B.; Wang, J.

2017-08-01

Semi-closed single screw refrigeration compressors (SSRC) are widely used in refrigeration and air conditioning systems owing to the advantages of simple structure, balanced forces on the rotor, high volumetric efficiency and so on. In semi-closed SSRCs, motor is often cooled by suction gas or injected refrigerant liquid. Motor cooling method will changes the suction gas temperature, this to a certain extent, is an important factor influencing the thermal dynamic performance of a compressor. Thus the effects of motor cooling method on the performance of the compressor must be studied. In this paper mathematical models of motor cooling process by using these two methods were established. Influences of motor cooling parameters such as suction gas temperature, suction gas quantity, temperature of the injected refrigerant liquid and quantity of the injected refrigerant liquid on the thermal dynamic performance of the compressor were analyzed. The performances of the compressor using these two kinds of motor cooling methods were compared. The motor cooling capacity of the injected refrigerant liquid is proved to be better than the suction gas. All analysis results obtained can be useful for optimum design of the motor cooling process to improve the efficiency and the energy efficiency of the compressor.

10 CFR Appendix A to Part 50 - General Design Criteria for Nuclear Power Plants

Code of Federal Regulations, 2012 CFR

2012-01-01

... Heat Removal 34 Emergency Core Cooling 35 Inspection of Emergency Core Cooling System 36 Testing of Emergency Core Cooling System 37 Containment Heat Removal 38 Inspection of Containment Heat Removal System 39 Testing of Containment Heat Removal System 40 Containment Atmosphere Cleanup 41 Inspection of...

10 CFR Appendix A to Part 50 - General Design Criteria for Nuclear Power Plants

Code of Federal Regulations, 2011 CFR

2011-01-01

... Heat Removal 34 Emergency Core Cooling 35 Inspection of Emergency Core Cooling System 36 Testing of Emergency Core Cooling System 37 Containment Heat Removal 38 Inspection of Containment Heat Removal System 39 Testing of Containment Heat Removal System 40 Containment Atmosphere Cleanup 41 Inspection of...

Review of Phase Change Materials Based on Energy Storage System with Applications

NASA Astrophysics Data System (ADS)

Thamaraikannn, R.; Kanimozhi, B.; Anish, M.; Jayaprabakar, J.; Saravanan, P.; Rohan Nicholas, A.

2017-05-01

The use of Different types of storage system using phase change materials (PCMs) is an effective way of storing energy and also to make advantages of heating and cooling systems are installed to maintain temperatures within the well-being zone. PCMs have been extensively used in various storage systems for heat pumps, solar engineering, and thermal control applications. The use of PCM’s for heating and cooling applications have been investigated during the past decade. There are large numbers of PCM’s, which melt and solidify at a wide range of temperatures, making them attractive in a number of applications. This paper also outline the investigation and analysis of Phase Change materials used in Different Types of storage systems with different applications.

Simulated responses of terrestrial aridity to black carbon and sulfate aerosols

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, L.; Gettelman, A.; Xu, Y.

Aridity index (AI), defined as the ratio of precipitation to potential evapotranspiration (PET), is a measure of the dryness of terrestrial climate. Global climate models generally project future decreases of AI (drying) associated with global warming scenarios driven by increasing greenhouse gas and declining aerosols. Given their different effects in the climate system, scattering and absorbing aerosols may affect AI differently. In this work, we explore the terrestrial aridity responses to anthropogenic black carbon (BC) and sulfate (SO 4) aerosols with Community Earth System Model simulations. Positive BC radiative forcing decreases precipitation averaged over global land at a rate ofmore » 0.9%/°C of global mean surface temperature increase (moderate drying), while BC radiative forcing increases PET by 1.0%/°C (also drying). BC leads to a global decrease of 1.9%/°C in AI (drying). SO 4 forcing is negative and causes precipitation a decrease at a rate of 6.7%/°C cooling (strong drying). PET also decreases in response to SO 4 aerosol cooling by 6.3%/°C cooling (contributing to moistening). Thus, SO 4 cooling leads to a small decrease in AI (drying) by 0.4%/°C cooling. Despite the opposite effects on global mean temperature, BC and SO 4 both contribute to the twentieth century drying (AI decrease). Sensitivity test indicates that surface temperature and surface available energy changes dominate BC- and SO 4-induced PET changes.« less

Simulated responses of terrestrial aridity to black carbon and sulfate aerosols

DOE PAGES

Lin, L.; Gettelman, A.; Xu, Y.; ...

2016-01-27

Aridity index (AI), defined as the ratio of precipitation to potential evapotranspiration (PET), is a measure of the dryness of terrestrial climate. Global climate models generally project future decreases of AI (drying) associated with global warming scenarios driven by increasing greenhouse gas and declining aerosols. Given their different effects in the climate system, scattering and absorbing aerosols may affect AI differently. In this work, we explore the terrestrial aridity responses to anthropogenic black carbon (BC) and sulfate (SO 4) aerosols with Community Earth System Model simulations. Positive BC radiative forcing decreases precipitation averaged over global land at a rate ofmore » 0.9%/°C of global mean surface temperature increase (moderate drying), while BC radiative forcing increases PET by 1.0%/°C (also drying). BC leads to a global decrease of 1.9%/°C in AI (drying). SO 4 forcing is negative and causes precipitation a decrease at a rate of 6.7%/°C cooling (strong drying). PET also decreases in response to SO 4 aerosol cooling by 6.3%/°C cooling (contributing to moistening). Thus, SO 4 cooling leads to a small decrease in AI (drying) by 0.4%/°C cooling. Despite the opposite effects on global mean temperature, BC and SO 4 both contribute to the twentieth century drying (AI decrease). Sensitivity test indicates that surface temperature and surface available energy changes dominate BC- and SO 4-induced PET changes.« less

Dynamic modeling of temperature change in outdoor operated tubular photobioreactors.

PubMed

Androga, Dominic Deo; Uyar, Basar; Koku, Harun; Eroglu, Inci

2017-07-01

In this study, a one-dimensional transient model was developed to analyze the temperature variation of tubular photobioreactors operated outdoors and the validity of the model was tested by comparing the predictions of the model with the experimental data. The model included the effects of convection and radiative heat exchange on the reactor temperature throughout the day. The temperatures in the reactors increased with increasing solar radiation and air temperatures, and the predicted reactor temperatures corresponded well to the measured experimental values. The heat transferred to the reactor was mainly through radiation: the radiative heat absorbed by the reactor medium, ground radiation, air radiation, and solar (direct and diffuse) radiation, while heat loss was mainly through the heat transfer to the cooling water and forced convection. The amount of heat transferred by reflected radiation and metabolic activities of the bacteria and pump work was negligible. Counter-current cooling was more effective in controlling reactor temperature than co-current cooling. The model developed identifies major heat transfer mechanisms in outdoor operated tubular photobioreactors, and accurately predicts temperature changes in these systems. This is useful in determining cooling duty under transient conditions and scaling up photobioreactors. The photobioreactor design and the thermal modeling were carried out and experimental results obtained for the case study of photofermentative hydrogen production by Rhodobacter capsulatus, but the approach is applicable to photobiological systems that are to be operated under outdoor conditions with significant cooling demands.

Simulated responses of terrestrial aridity to black carbon and sulfate aerosols: LIN: SIMULATED RESPONSES ARIDITY

DOE PAGES

Lin, L.; Gettelman, A.; Xu, Y.; ...

2016-01-27

Aridity index (AI), defined as the ratio of precipitation to potential evapotranspiration (PET), is a measure of the dryness of terrestrial climate. Global climate models generally project future decreases of AI (drying) associated with global warming scenarios driven by increasing greenhouse gas and declining aerosols. Given their different effects in the climate system, scattering and absorbing aerosols may affect AI differently. Here we explore the terrestrial aridity responses to anthropogenic black carbon (BC) and sulfate (SO4) aerosols with Community Earth System Model simulations. Positive BC radiative forcing decreases precipitation averaged over global land at a rate of 0.9%/°C of globalmore » mean surface temperature increase (moderate drying), while BC radiative forcing increases PET by 1.0%/°C (also drying). BC leads to a global decrease of 1.9%/°C in AI (drying). SO4 forcing is negative and causes precipitation a decrease at a rate of 6.7%/°C cooling (strong drying). PET also decreases in response to SO4 aerosol cooling by 6.3%/°C cooling (contributing to moistening). Thus, SO4 cooling leads to a small decrease in AI (drying) by 0.4%/°C cooling. Despite the opposite effects on global mean temperature, BC and SO4 both contribute to the twentieth century drying (AI decrease). Sensitivity test indicates that surface temperature and surface available energy changes dominate BC- and SO4-induced PET changes.« less

Effective micro-spray cooling for light-emitting diode with graphene nanoporous layers

NASA Astrophysics Data System (ADS)

Keong Lay, Kok; Yew Cheong, Brian Mun; Li Tong, Wei; Tan, Ming Kwang; Hung, Yew Mun

2017-04-01

A graphene nanoplatelet (GNP) coating is utilized as a functionalized surface in enhancing the evaporation rate of micro-spray cooling for light-emitting diodes (LEDs). In micro-spray cooling, water is atomized into micro-sized droplets to reduce the surface energy and to increase the surface area for evaporation. The GNP coating facilitates the effective filmwise evaporation through the attribute of fast water permeation. The oxygenated functional groups of GNPs provide the driving force that initiates the intercalation of water molecules through the carbon nanostructure. The water molecules slip through the frictionless passages between the hydrophobic carbon walls, resulting an effective filmwise evaporation. The enhancement of evaporation leads to an enormous temperature reduction of 61.3 °C. The performance of the LED is greatly enhanced: a maximum increase in illuminance of 25% and an extension of power rating from 9 W to 12 W can be achieved. With the application of GNP coating, the high-temperature region is eliminated while maintaining the LED surface temperature for optimal operation. This study paves the way for employing the effective hybrid spray-evaporation-nanostructure technique in the development of a compact, low-power-consumption cooling system.

Combined cooling and purification system for nuclear reactor spent fuel pit, refueling cavity, and refueling water storage tank

DOEpatents

Corletti, Michael M.; Lau, Louis K.; Schulz, Terry L.

1993-01-01

The spent fuel pit of a pressured water reactor (PWR) nuclear power plant has sufficient coolant capacity that a safety rated cooling system is not required. A non-safety rated combined cooling and purification system with redundant branches selectively provides simultaneously cooling and purification for the spent fuel pit, the refueling cavity, and the refueling water storage tank, and transfers coolant from the refueling water storage tank to the refueling cavity without it passing through the reactor core. Skimmers on the suction piping of the combined cooling and purification system eliminate the need for separate skimmer circuits with dedicated pumps.

Ground source heat pumps (GSHP) for heating and cooling in Greece

NASA Astrophysics Data System (ADS)

Dimera, Nikoletta

This report presents the results of a theoretical study about the feasibility of closed loop Ground Source Heat Pumps (GSHP) for heating and cooling in Greece in terms of their impact on the capital and running costs of the building services systems of the buildings. The main aim of carrying out this study was to investigate if the heating and cooling potential of the ground could be utilized cost efficiently to serve the buildings energy demand in the Greek region. At first, an existing implementation of a closed loop GSHP system in Greece is presented and its efficiency is discussed. The aim of doing so was to understand the way of sizing such systems and the efficiency of this technology in Greek climatic and ground conditions. In a separate part of this report, the impact of different user behaviour and of various ways of sizing a GSHP system is investigated in terms of the cost impact of the examined different options as well as of their effect on the internal health and comfort conditions. After the building simulation under different scenarios, it was concluded that the user behavior - the operation of windows mostly - can result in great savings on the annual energy bills. The conclusions of this first part of the report about the user behaviour and the way of sizing GSHP systems were utilized in the next part of it, where a GSHP system is proposed for a building currently under construction in central Greece. A simple 30-year cost analysis was used in order to estimate the performance of the proposed GSHP system in economic terms and to compare it with the conventional HVAC system commonly used in Greece. According to the results of the analysis, the capital cost of installing a GSHP system for heating and cooling in buildings in Greece appears higher than the cost of conventional HVAC systems. More specifically, the capital cost of an installation for heating including gas boilers and a cooling system based on air conditioning split units is about the half of installing a GSHP system for heating and cooling designed to serve the same loads. On the other hand, if the conventional HVAC system included cooling towers instead of A/C split units, the capital cost of such the installation raises up to double the price of the GSHP system for the same needs. However, after a 30-years period of continuous use of the systems, the money spent for installing and running the GSHP system are about the half of those that should be paid once a conventional HVAC system was preferred for the same energy demand.

Systemic effects of whole-body cooling to 35°C, 33.5°C and 30°C in a piglet perinatal asphyxia model: implications for therapeutic hypothermia

PubMed Central

Kerenyi, Aron; Kelen, Dorottya; Faulkner, Stuart D; Bainbridge, Alan; Chandrasekaran, Manigandan; Cady, Ernest B; Golay, Xavier; Robertson, Nicola J

2014-01-01

The precise temperature for optimal neuroprotection in infants with neonatal encephalopathy is unclear. Our aim was to assess systemic effects of whole-body cooling to 35°C, 33.5°C and 30°C in a piglet perinatal asphyxia model. Twenty-eight anesthetised male piglets aged <24h underwent hypoxia-ischemia and randomized to normothermia; or cooling to rectal temperature (Trec) 35°C, 33.5°C, or 30°C during 2-26 h post insult (groups n=7). Heart rate (HR), mean arterial blood pressure (MABP) and Trec were recorded continuously. Five 30°C animals had fatal cardiac arrests. During 30°C cooling HR was lower vs normothermia (p<0.001). Although MABP did not vary between groups, more fluid boluses were needed at 30°C than normothermia (p<0.02); dopamine use was higher at 30°C than normothermia and 35°C (p=0.005, p=0.02). Base deficit was increased at 30°C at 12,24 and 36h vs all other groups (p<0.05), pH was acidotic at 36h vs normothermia (p=0.04) and blood glucose higher for 30°C at 12h vs normothermia and 35°C (p<0.05). Potassium was lower at 12h in the 30°C group vs 33.5°C and 35°C groups. Cortisol was no different between groups. Cooling to 30°C led to metabolic derangement, more cardiac arrests and deaths than cooling to 33.5°C or 35°C. Inadvertent overcooling should be avoided. PMID:22314664

Relativistic turbulence with strong synchrotron and synchrotron self-Compton cooling

NASA Astrophysics Data System (ADS)

Uzdensky, D. A.

2018-07-01

Many relativistic plasma environments in high-energy astrophysics, including pulsar wind nebulae (PWN), hot accretion flows on to black holes, relativistic jets in active galactic nuclei and gamma-ray bursts, and giant radio lobes, are naturally turbulent. The plasma in these environments is often so hot that synchrotron and inverse-Compton (IC) radiative cooling becomes important. In this paper, we investigate the general thermodynamic and radiative properties (and hence the observational appearance) of an optically thin relativistically hot plasma stirred by driven magnetohydrodynamic (MHD) turbulence and cooled by radiation. We find that if the system reaches a statistical equilibrium where turbulent heating is balanced by radiative cooling, the effective electron temperature tends to attain a universal value θ = kT_e/m_e c^2 ˜ 1/√{τ _T}, where τT = neσTL ≪ 1 is the system's Thomson optical depth, essentially independent of the strength of turbulent driving and hence of the magnetic field. This is because both MHD turbulent dissipation and synchrotron cooling are proportional to the magnetic energy density. We also find that synchrotron self-Compton (SSC) cooling and perhaps a few higher order IC components are automatically comparable to synchrotron in this regime. The overall broad-band radiation spectrum then consists of several distinct components (synchrotron, SSC, etc.), well separated in photon energy (by a factor ˜ τ_T^{-1}) and roughly equal in power. The number of IC peaks is checked by Klein-Nishina effects and depends logarithmically on τT and the magnetic field. We also examine the limitations due to synchrotron self-absorption, explore applications to Crab PWN and blazar jets, and discuss links to radiative magnetic reconnection.

Regeneratively cooled transition duct with transversely buffered impingement nozzles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morrison, Jay A; Lee, Ching-Pang; Crawford, Michael E

2015-04-21

A cooling arrangement (56) having: a duct (30) configured to receive hot gases (16) from a combustor; and a flow sleeve (50) surrounding the duct and defining a cooling plenum (52) there between, wherein the flow sleeve is configured to form impingement cooling jets (70) emanating from dimples (82) in the flow sleeve effective to predominately cool the duct in an impingement cooling zone (60), and wherein the flow sleeve defines a convection cooling zone (64) effective to cool the duct solely via a cross-flow (76), the cross-flow comprising cooling fluid (72) exhausting from the impingement cooling zone. In themore » impingement cooling zone an undimpled portion (84) of the flow sleeve tapers away from the duct as the undimpled portion nears the convection cooling zone. The flow sleeve is configured to effect a greater velocity of the cross-flow in the convection cooling zone than in the impingement cooling zone.« less

Novel thermal management system using boiling cooling for high-powered lithium-ion battery packs for hybrid electric vehicles

NASA Astrophysics Data System (ADS)

Al-Zareer, Maan; Dincer, Ibrahim; Rosen, Marc A.

2017-09-01

A thermal management system is necessary to control the operating temperature of the lithium ion batteries in battery packs for electrical and hybrid electrical vehicles. This paper proposes a new battery thermal management system based on one type of phase change material for the battery packs in hybrid electrical vehicles and develops a three dimensional electrochemical thermal model. The temperature distributions of the batteries are investigated under various operating conditions for comparative evaluations. The proposed system boils liquid propane to remove the heat generated by the batteries, and the propane vapor is used to cool the part of the battery that is not covered with liquid propane. The effect on the thermal behavior of the battery pack of the height of the liquid propane inside the battery pack, relative to the height of the battery, is analyzed. The results show that the propane based thermal management system provides good cooling control of the temperature of the batteries under high and continuous charge and discharge cycles at 7.5C.

Reduction of vibration forces transmitted from a radiator cooling fan to a vehicle body

NASA Astrophysics Data System (ADS)

Lim, Jonghyuk; Sim, Woojeong; Yun, Seen; Lee, Dongkon; Chung, Jintai

2018-04-01

This article presents methods for reducing transmitted vibration forces caused by mass unbalance of the radiator cooling fan during vehicle idling. To identify the effects of mass unbalance upon the vibration characteristics, vibration signals of the fan blades were experimentally measured both with and without an added mass. For analyzing the vibration forces transmitted to the vehicle body, a dynamic simulation model was established that reflected the vibration characteristics of the actual system. This process included a method described herein for calculating the equivalent stiffness and the equivalent damping of the shroud stators and rubber mountings. The dynamic simulation model was verified by comparing its results with experimental results of the radiator cooling fan. The dynamic simulation model was used to analyze the transmitted vibration forces at the rubber mountings. Also, a measure was established to evaluate the effects of varying the design parameters upon the transmitted vibration forces. We present design guidelines based on these analyses to reduce the transmitted vibration forces of the radiator cooling fan.

Heat exchanger with auxiliary cooling system

DOEpatents

Coleman, John H.

1980-01-01

A heat exchanger with an auxiliary cooling system capable of cooling a nuclear reactor should the normal cooling mechanism become inoperable. A cooling coil is disposed around vertical heat transfer tubes that carry secondary coolant therethrough and is located in a downward flow of primary coolant that passes in heat transfer relationship with both the cooling coil and the vertical heat transfer tubes. A third coolant is pumped through the cooling coil which absorbs heat from the primary coolant which increases the downward flow of the primary coolant thereby increasing the natural circulation of the primary coolant through the nuclear reactor.

Relativistic MHD Turbulence with Synchrotron and Inverse-Compton Radiation Cooling

NASA Astrophysics Data System (ADS)

Uzdensky, Dmitri

2017-10-01

This work investigates the energetic aspects and observational appearance of driven relativistic MHD turbulence in an optically thin, relativistically hot plasma subject to strong synchrotron and synchrotron-self-Compton (SSC) radiative cooling. Steady-state balance between turbulent heating and radiative cooling is shown to lead, essentially independent of turbulent driving's strength, to a characteristic electron temperature of Te /mec2 τT- 1 / 2 , where τT << 1 is the system's Thomson optical depth. Furthermore, the SSC cooling power becomes automatically comparable to the synchrotron power. Under certain conditions, a few higher-order inverse-Compton components also become comparable to the synchrotron and SSC losses, and so the broad-band radiation spectrum of the system consists of several distinct peaks with gradually decreasing luminosity, separated by a factor of τT- 1 >> 1 from each other. The number of these spectral components is governed by synchrotron self-absorption and Klein-Nishina effects. These findings have important implications for several classes of high-energy astrophysical systems including pulsar wind nebulae and black-hole-driven accretion flows, jets, and radio-lobes. Work supported by NSF, DOE, NASA, IAS, and the Ambrose Monell Foundation.

Passive cooling system for nuclear reactor containment structure

DOEpatents

Gou, Perng-Fei; Wade, Gentry E.

1989-01-01

A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.

Intra-Abdominal Cooling System Limits Ischemia-Reperfusion Injury During Robot-Assisted Renal Transplantation.

PubMed

Meier, R P H; Piller, V; Hagen, M E; Joliat, C; Buchs, J-B; Nastasi, A; Ruttimann, R; Buchs, N C; Moll, S; Vallée, J-P; Lazeyras, F; Morel, P; Bühler, L

2018-01-01

Robot-assisted kidney transplantation is feasible; however, concerns have been raised about possible increases in warm ischemia times. We describe a novel intra-abdominal cooling system to continuously cool the kidney during the procedure. Porcine kidneys were procured by standard open technique. Groups were as follows: Robotic renal transplantation with (n = 11) and without (n = 6) continuous intra-abdominal cooling and conventional open technique with intermittent 4°C saline cooling (n = 6). Renal cortex temperature, magnetic resonance imaging, and histology were analyzed. Robotic renal transplantation required a longer anastomosis time, either with or without the cooling system, compared to the open approach (70.4 ± 17.7 min and 74.0 ± 21.5 min vs. 48.7 ± 11.2 min, p-values < 0.05). The temperature was lower in the robotic group with cooling system compared to the open approach group (6.5 ± 3.1°C vs. 22.5 ± 6.5°C; p = 0.001) or compared to the robotic group without the cooling system (28.7 ± 3.3°C; p < 0.001). Magnetic resonance imaging parenchymal heterogeneities and histologic ischemia-reperfusion lesions were more severe in the robotic group without cooling than in the cooled (open and robotic) groups. Robot-assisted kidney transplantation prolongs the warm ischemia time of the donor kidney. We developed a novel intra-abdominal cooling system that suppresses the noncontrolled rewarming of donor kidneys during the transplant procedure and prevents ischemia-reperfusion injuries. © 2017 The Authors. American Journal of Transplantation published by Wiley Periodicals, Inc. on behalf of American Society of Transplant Surgeons.

Effect of operating conditions on performance of silica gel-water air-fluidised desiccant cooler

NASA Astrophysics Data System (ADS)

Rogala, Zbigniew; Kolasiński, Piotr; Gnutek, Zbigniew

2017-11-01

Fluidised desiccant cooling is reported in the literature as an efficient way to provide cooling for air-conditioning purposes. The performance of this technology can be described by electric and thermal Coefficients of Performance (COP) and Specific Cooling Power (SCP). In this paper comprehensive theoretical study was carried out in order to assess the effect of operating conditions such as: superficial air velocity, desiccant particle diameter, bed switching time and desiccant filling height on the performance of fluidised desiccant cooler (FDC). It was concluded that FDC should be filled with as small as possible desiccant particles featuring diameters and should not be operated with shorter switching times than optimum. Moreover in order to efficiently run such systems superficial air velocities during adsorption and desorption should be similar. At last substantial effect of desiccant filling height on performance of FDC was presented.

DEVELOP A CONCENTRATED SOLAR POWER-BASED THERMAL COOLING SYSTEM VIA SIMULATION AND EXPERIMENTAL STUDIES

EPA Science Inventory

A small scale CSP-based cooling system prototype (300W cooling capacity) and the system performance simulation tool will be developed as a proof of concept. Practical issues will be identified to improve our design.

System and method for regulating EGR cooling using a Rankine cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ernst, Timothy C.; Morris, Dave

This disclosure relates to a waste heat recovery (WHR) system and method for regulating exhaust gas recirculation (EGR) cooling, and more particularly, to a Rankine cycle WHR system and method, including a recuperator bypass arrangement to regulate EGR exhaust gas cooling for engine efficiency improvement and thermal management. This disclosure describes other unique bypass arrangements for increased flexibility in the ability to regulate EGR exhaust gas cooling.

System and method for regulating EGR cooling using a rankine cycle

DOEpatents

Ernst, Timothy C.; Morris, Dave

2015-12-22

This disclosure relates to a waste heat recovery (WHR) system and method for regulating exhaust gas recirculation (EGR) cooling, and more particularly, to a Rankine cycle WHR system and method, including a recuperator bypass arrangement to regulate EGR exhaust gas cooling for engine efficiency improvement and thermal management. This disclosure describes other unique bypass arrangements for increased flexibility in the ability to regulate EGR exhaust gas cooling.

Temperature Mapping of Air Film-Cooled Thermal Barrier Coated Surfaces Using Phosphor Thermometry

NASA Technical Reports Server (NTRS)

Eldridge, Jeffrey I.

2016-01-01

While the effects of thermal barrier coating (TBC) thermal protection and air film cooling effectiveness for jet engine components are usually studied separately, their contributions to combined cooling effectiveness are interdependent and are not simply additive. Therefore, combined cooling effectiveness must be measured to achieve an optimum balance between TBC thermal protection and air film cooling. Phosphor thermometry offers several advantages for mapping temperatures of air film cooled surfaces. While infrared thermography has been typically applied to study air film cooling effectiveness, temperature accuracy depends on knowing surface emissivity (which may change) and correcting for effects of reflected radiation. Because decay time-based full-field phosphor thermometry is relatively immune to these effects, it can be applied advantageously to temperature mapping of air film-cooled TBC-coated surfaces. In this presentation, an overview will be given of efforts at NASA Glenn Research Center to perform temperature mapping of air film-cooled TBC-coated surfaces in a burner rig test environment. The effects of thermal background radiation and flame chemiluminescence on the measurements are investigated, and the strengths and limitations of this method for studying air film cooling effectiveness are discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andersson, B.

This paper will present the status of the development of district cooling systems in Scandinavia over the last 5 years. It will describe the technologies used in the systems that have been constructed as well as the options considered in different locations. It will identify the drivers for the development of the cooling business to-date, and what future drivers for a continuing development of district cooling in Sweden. To-date, approximately 25 different cities of varying sizes have completed feasibility studies to determine if district cooling is an attractive option. In a survey, that was conducted by the Swedish District Heatingmore » Association, some 25 cities expected to have district cooling systems in place by the year 2000. In Sweden, district heating systems with hot water is very common. In many cases, it is simply an addition to the current service for the district heating company to also supply district cooling to the building owners. A parallel from this can be drawn to North America where district cooling systems now are developing rapidly. I am convinced that in these cities a district heating service will be added as a natural expansion of the district cooling company`s service.« less

Evaluation of Commercial Off-the-Shelf and Government Off-the-Shelf Microclimate Cooling Systems

DTIC Science & Technology

2005-08-01

Appendix A - Request for Information (RFI) 23 Appendix B - Memorandum from Natick Soldier Center’s International Office 25 Appendix C - Cooling Power...Data Entry Forms 7 Figure 3. Evaporative Cooling Products 9 Figure 4. Passive Phase Change Product 10 Figure 5. Liquid Circulating...Microclimate Cooling System 13 Figure 6. Compressed Air Cooling Product 15 Figure 7. Vortex Tube 15 Figure 8. Active Phase

Effects of evaporative cooling on the regulation of body water and milk production in crossbred Holstein cattle in a tropical environment

NASA Astrophysics Data System (ADS)

Chaiyabutr, N.; Chanpongsang, S.; Suadsong, S.

2008-09-01

The aim of this study was to determine how evaporative cooling modifies body function with respect to water metabolism and other variables relevant to milk synthesis in crossbred cattle. The study was conducted on two groups of 0.875HF:0.125RS crossbred Holstein cattle (87.5%) housed in an open-sided barn with a tiled roof (non-cooled animals) and in a close-sided barn under an evaporative cooling system (cooled animals). The maximum ambient temperature and relative humidity for the non-cooled group were 33°C and 61%, with the corresponding values for the evaporatively cooled barn being 28°C and 84%, respectively. The temperature humidity index (THI) of under non-cooled conditions was higher ( P < 0.05) than that in the cooled barn. Rectal temperatures and respiration rates of non-cooled animals were higher ( P < 0.05) than those of cooled animals. Daily dry matter intake (DMI) of cooled animals was higher while water intakes were lower ( P < 0.05) than those of non-cooled animals. The mean absolute values of plasma volume, blood volume, and extracellular fluid (ECF) of cooled animals were significantly higher ( P < 0.05) than those of non-cooled animals throughout all stages of lactation. Milk yields of cooled animals were higher by 42%, 36% and 79% on average than those of non-cooled animals during early-, mid- and late-lactation, respectively. The decline in milk yields as lactation advances was markedly apparent in late-lactating non-cooled animals, while no significant changes in milk composition at different stages of lactation were observed in either group. Mean arterial plasma concentrations, arteriovenous concentration differences (A-V differences) and the extraction ratio across the mammary gland for acetate, glucose and triglyceride of cooled animals were not significantly different compared with values for non-cooled animals. No differences were seen in plasma hormonal levels for triiodotyronine (T3) and insulin-like growth factor-1 (IGF-1), but plasma cortisol and thyroxine (T4) levels tended to be lower in non-cooled animals. This study suggests that low cooling temperature accompanied by high humidity influences a galactopoietic effect, in part through increases in ECF, blood volume and plasma volume in association with an increase in DMI, which partitions the distribution of nutrients to the mammary gland for milk synthesis. Cooled animals were unable to maintain high milk yield as lactation advances even though a high level of body fluids was maintained during long-term cooled exposure. The decline in milk yield, coinciding with a decrease in net energy for lactation as lactation advances, could be attributed to a local change within the mammary gland.

Aquifer thermal-energy-storage costs with a seasonal-chill source

NASA Astrophysics Data System (ADS)

Brown, D. R.

1983-01-01

The cost of energy supplied by an aquifer thermal energy storage (ATES) ystem from a seasonal chill source was investigated. Costs were estimated for point demand and residential development ATES systems using the computer code AQUASTOR. AQUASTOR was developed at PNL specifically for the economic analysis of ATES systems. In this analysis the cost effect of varying a wide range of technical and economic parameters was examined. Those parameters exhibiting a substantial influence on the costs of ATES delivered chill were: system size; well flow rate; transmission distance; source temperature; well depth; and cost of capital. The effects of each parameter are discussed. Two primary constraints of ATES chill systems are the extremely low energy density of the storage fluid and the prohibitive costs of lengthly pipelines for delivering chill to residential users. This economic analysis concludes that ATES-delivered chill will not be competitive for residential cooling applications. The otherwise marginal attractiveness of ATES chill systems vanishes under the extremely low load factors characteristic of residential cooling systems. (LCL)

Improving the viability and versatility of the E × B probe with an active cooling system.

PubMed

Liu, Lihui; Cai, Guobiao; You, Fengyi; Ren, Xiang; Zheng, Hongru; He, Bijiao

2018-04-01

A thermostatic E × B probe is designed to protect the probe body from the thermal effect of the plasma plume that has a significant influence on the resolution of the probe for high-power electric thrusters. An active cooling system, which consists of a cooling panel and carbon fiber felts combined with a recycling system of liquid coolants or an open-type system of gas coolants, is employed to realize the protection of the probe. The threshold for the design parameters for the active cooling system is estimated by deriving the energy transfer of the plasma plume-probe body interaction and the energy taken away by the coolants, and the design details are explained. The diagnostics of the LIPS-300 ion thruster with a power of 3 kW and a screen-grid voltage of 1450 V was implemented by the designed thermostatic E × B probe. The measured spectra illustrate that the thermostatic E × B probe can distinguish the fractions of Xe + ions and Xe 2+ ions without areas of overlap. In addition, the temperature of the probe body was less than 306 K in the beam region of the plasma plume during the 200-min-long continuous test. A thermostatic E × B probe is useful for enhancing the viability and versatility of equipment and for reducing uneconomical and complex test procedures.

Improving the viability and versatility of the E × B probe with an active cooling system

NASA Astrophysics Data System (ADS)

Liu, Lihui; Cai, Guobiao; You, Fengyi; Ren, Xiang; Zheng, Hongru; He, Bijiao

2018-04-01

A thermostatic E × B probe is designed to protect the probe body from the thermal effect of the plasma plume that has a significant influence on the resolution of the probe for high-power electric thrusters. An active cooling system, which consists of a cooling panel and carbon fiber felts combined with a recycling system of liquid coolants or an open-type system of gas coolants, is employed to realize the protection of the probe. The threshold for the design parameters for the active cooling system is estimated by deriving the energy transfer of the plasma plume-probe body interaction and the energy taken away by the coolants, and the design details are explained. The diagnostics of the LIPS-300 ion thruster with a power of 3 kW and a screen-grid voltage of 1450 V was implemented by the designed thermostatic E × B probe. The measured spectra illustrate that the thermostatic E × B probe can distinguish the fractions of Xe+ ions and Xe2+ ions without areas of overlap. In addition, the temperature of the probe body was less than 306 K in the beam region of the plasma plume during the 200-min-long continuous test. A thermostatic E × B probe is useful for enhancing the viability and versatility of equipment and for reducing uneconomical and complex test procedures.

Hemodynamic and thermal responses to head and neck cooling in men and women

NASA Technical Reports Server (NTRS)

Ku, Y. T.; Montgomery, L. D.; Webbon, B. W.

1996-01-01

Personal cooling systems are used to alleviate symptoms of multiple sclerosis and to prevent increased core temperature during daily activities. The objective of this study was to determine the operating characteristics and the physiologic changes produced by short term use of one commercially available thermal control system. A Life Support Systems, Inc. Mark VII portable cooling system and a liquid cooling helmet were used to cool the head and neck regions of 12 female and 12 male subjects (25-55 yr) in this study. The healthy subjects, seated in an upright position at normal room temperature (approximately 21 degrees C), were tested for 30 min with the liquid cooling garment operated at its maximum cooling capacity. Electrocardiograms and scalp and intracranial blood flows were recorded periodically during each test sequence. Scalp, right and left ear, and oral temperatures and cooling system parameters were logged every 5 min. Scalp, right and left ear canal, and oral temperatures were all significantly (P <0.05) reduced by 30 min of head and neck cooling. Oral temperatures decreased approximately 0.2-0.6 degrees C after 30 min and continued to decrease further (approximately 0.1-0.2 degrees C) for a period of approximately 10 min after removal of the cooling helmet. Intracranial blood flow decreased significantly (P < 0.05) during the first 10 min of the cooling period. Both right and left ear temperatures in the women were significantly lower than those of the men during the cooling period. These data indicate that head and neck cooling may be used to reduce core temperature to that needed for symptomatic relief of both male and female multiple sclerosis patients. This study quantifies the operating characteristics of one liquid cooling garment as an example of the information needed to compare the efficiency of other garments operated under different test conditions.

Thermoelectrics in Coulomb-coupled quantum dots: Cotunneling and energy-dependent lead couplings

NASA Astrophysics Data System (ADS)

Walldorf, Nicklas; Jauho, Antti-Pekka; Kaasbjerg, Kristen

2017-09-01

We study thermoelectric effects in Coulomb-coupled quantum-dot (CCQD) systems beyond lowest-order tunneling processes and the often applied wide-band approximation. To this end, we present a master-equation (ME) approach based on a perturbative T -matrix calculation of the charge and heat tunneling rates and transport currents. Applying the method to transport through a noninteracting single-level QD, we demonstrate excellent agreement with the Landauer-Büttiker theory when higher-order (cotunneling) processes are included in the ME. Next, we study the effect of cotunneling and energy-dependent lead couplings on the heat currents in a system of two CCQDs. We find that cotunneling processes (i) can dominate the off-resonant heat currents at low temperature and bias compared to the interdot interaction, and (ii) give rise to a pronounced reduction of the cooling power achievable with the recently demonstrated Maxwell's demon cooling mechanism. Furthermore, we demonstrate that the cooling power can be boosted significantly by carefully engineering the energy dependence of the lead couplings to filter out undesired transport processes. Our findings emphasize the importance of higher-order cotunneling processes as well as engineered energy-dependent lead couplings in the optimization of the thermoelectric performance of CCQD systems.

Experimental study on internal cooling system in hard turning of HCWCI using CBN tools

NASA Astrophysics Data System (ADS)

Ravi, A. M.; Murigendrappa, S. M.

2018-04-01

In recent times, hard turning became most emerging technique in manufacturing processes, especially to cut high hard materials like high chrome white cast iron (HCWCI). Use of Cubic boron nitride (CBN), pCBN and Carbide tools are most appropriate to shear the metals but are uneconomical. Since hard turning carried out in dry condition, lowering the tool wear by minimizing tool temperature is the only solution. Study reveals, no effective cooling systems are available so for in order to enhance the tool life of the cutting tools and to improve machinability characteristics. The detrimental effect of cutting parameters on cutting temperature is generally controlled by proper selections. The objective of this paper is to develop a new cooling system to control tool tip temperature, thereby minimizing the cutting forces and the tool wear rates. The materials chosen for this work was HCWCI and cutting tools are CBN inserts. Intricate cavities were made on the periphery of the tool holder for easy flow of cold water. Taguchi techniques were adopted to carry out the experimentations. The experimental results confirm considerable reduction in the cutting forces and tool wear rates.

Overnight storage of whole blood: cooling and transporting blood at room temperature under extreme temperature conditions.

PubMed

Thibault, L; Beauséjour, A; Jacques, A; Ducas, E; Tremblay, M

2014-02-01

Many countries allow the overnight storage of whole blood (WB) at ambient temperature. Some countries, such as Canada, also require a rapid cooling of WB with an active cooling system. Given the significant operational constraints associated with current cooling systems, an alternative method for cooling and transporting WB at 20-24°C was evaluated. Phase 22 cooling packs (TCP Reliable Inc., USA) were used in combination with vacuum-insulated panel (VIP) boxes. Temperature profiles of simulated WB units were studied in extreme temperatures (-35 and 40°C). The quality of blood components prepared using Phase 22 packs and CompoCool-WB (Fresenius HemoCare, Germany) was studied. Phase 22 packs reduced the temperature of simulated WB bags from 37 to 24°C in 1·7 ± 0·2 h. Used in combination with VIP boxes, Phase 22 packs maintain the temperature of bags between 20 and 24°C for 15 and 24 h, compared to 2 and 11 h with CompoCool-WB, when exposed at -35 and 40°C, respectively. The quality of platelet concentrates and plasma was comparable, regardless of the cooling system used. For red blood cell units, per cent haemolysis on day 42 was slightly higher in products prepared after cooling with Phase 22 packs compared to CompoCool-WB (0·33 ± 0·15% vs. 0·21 ± 0·06%; P < 0·05). Phase 22 packs combined with VIP boxes are an acceptable alternative to butane-1,4-diol cooling systems. This system allows blood manufacturers to transport WB to processing facilities in a broad range of environmental conditions. © 2013 International Society of Blood Transfusion.

Coupled Cryogenic Thermal and Electrical Models for Transient Analysis of Superconducting Power Devices with Integrated Cryogenic Systems

NASA Astrophysics Data System (ADS)

Satyanarayana, S.; Indrakanti, S.; Kim, J.; Kim, C.; Pamidi, S.

2017-12-01

Benefits of an integrated high temperature superconducting (HTS) power system and the associated cryogenic systems on board an electric ship or aircraft are discussed. A versatile modelling methodology developed to assess the cryogenic thermal behavior of the integrated system with multiple HTS devices and the various potential configurations are introduced. The utility and effectiveness of the developed modelling methodology is demonstrated using a case study involving a hypothetical system including an HTS propulsion motor, an HTS generator and an HTS power cable cooled by an integrated cryogenic helium circulation system. Using the methodology, multiple configurations are studied. The required total cooling power and the ability to maintain each HTS device at the required operating temperatures are considered for each configuration and the trade-offs are discussed for each configuration. Transient analysis of temperature evolution in the cryogenic helium circulation loop in case of a system failure is carried out to arrive at the required critical response time. The analysis was also performed for a similar liquid nitrogen circulation for an isobaric condition and the cooling capacity ratio is used to compare the relative merits of the two cryogens.

Performance of Introducing Outdoor Cold Air for Cooling a Plant Production System with Artificial Light

PubMed Central

Wang, Jun; Tong, Yuxin; Yang, Qichang; Xin, Min

2016-01-01

The commercial use of a plant production system with artificial light (PPAL) is limited by its high initial construction and operation costs. The electric-energy consumed by heat pumps, applied mainly for cooling, accounts for 15–35% of the total electric-energy used in a PPAL. To reduce the electric-energy consumption, an air exchanger with low capacity (180 W) was used for cooling by introducing outdoor cold air. In this experiment, the indoor air temperature in two PPALs (floor area: 6.2 m2 each) was maintained at 25 and 20°C during photoperiod and dark period, respectively, for lettuce production. A null CO2 balance enrichment method was used in both PPALs. In one PPAL (PPALe), an air exchanger (air flow rate: 250 m3·h−1) was used along with a heat pump (cooling capacity: 3.2 kW) to maintain the indoor air temperature at the set-point. The other PPAL (PPALc) with only a heat pump (cooling capacity: 3.2 kW) was used for reference. Effects of introducing outdoor cold air on energy use efficiency, coefficient of performance (COP), electric-energy consumption for cooling and growth of lettuce were investigated. The results show that: when the air temperature difference between indoor and outdoor ranged from 20.2 to 30.0°C: (1) the average energy use efficiency of the air exchanger was 2.8 and 3.4 times greater than the COP of the heat pumps in the PPALe and PPALc, respectively; (2) hourly electric-energy consumption for cooling in the PPALe reduced by 15.8–73.7% compared with that in the PPALc; (3) daily supply of CO2 in the PPALe reduced from 0.15 to 0.04 kg compared with that in the PPALc with the outdoor air temperature ranging from −5.6 to 2.7°C; (4) no significant difference in lettuce growth was observed in both PPALs. The results indicate that using air exchanger to introduce outdoor cold air should be considered as an effective way to reduce electric-energy consumption for cooling with little effects on plant growth in a PPAL. PMID:27066012

Mobile refrigeration system for precool and warm up of superconducting magnets

NASA Astrophysics Data System (ADS)

Gandla, S. K.; Longsworth, R. C.

2017-12-01

Conservation of helium has become more important in recent years due to global shortages in supply. Magnetic resonance imaging (MRI) superconducting magnets use approximately 20% of the world’s helium reserves in liquid form to cool down and maintain operating temperatures at 4 K. This paper describes a mobile cryogenic refrigeration system, which has been developed by Sumitomo (SHI) Cryogenics of America, Inc. to conserve helium by shipping MRI magnets warm and cooling them down or servicing them on site at a medical facility. The system can cool a typical magnet from room temperature to below 40K in less than a week. The system consists of four single stage Displex®-type Gifford-McMahon (GM) expanders in a cryostat with heat exchangers integrated on the cold ends that cool the helium gas, which is circulated in a closed-loop system through the magnet by a cryogenic fan. The system is configured with heaters on the heat exchangers to effectively warm up a magnet. The system includes a scroll vacuum pump, which is used to evacuate the helium circuit with or without the magnet and turbo pump to evacuate the cryostat. Vacuum-jacketed transfer lines connect the cryostat to the magnet. The system is designed with its own controller for continuous operation of precool, warm up and evacuation processes with automatic and manual controls. The cryostat, pumps and gas controls are mounted on a dewar cart. One compressor and the system controller are mounted on a compressor and control cart, and the other three compressors are mounted on separate carts.

Solar energy for a community recreation center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libman, D.E.

1980-01-01

A 58,000 ft/sup 2/ recreation center in Shenandoah, Georgia is described. Rooftop solar collectors and reflectors serve as a basis for the active solar heating and cooling systems. The recreation center clearly demonstrates the technical feasibility of solar application in a recreation setting; economically, however, results are shown to be mixed. Although effective in the heating mode, solar cooling is considered as questionable in terms of a reasonable payoff period. A computer model predicts a payoff period of 11 years based on 1977 energy prices. The design and construction costs of the solar heating and cooling system ($726,000) was 90%more » financed by ERDA. A hockey-size ice rink and a gymnasium plus locker rooms and meeting rooms comprised the major part of the floor space. Problems encountered and operation of the facility are described. (MJJ)« less

Systemic effects of whole-body cooling to 35 °C, 33.5 °C, and 30 °C in a piglet model of perinatal asphyxia: implications for therapeutic hypothermia.

PubMed

Kerenyi, Aron; Kelen, Dorottya; Faulkner, Stuart D; Bainbridge, Alan; Chandrasekaran, Manigandan; Cady, Ernest B; Golay, Xavier; Robertson, Nicola J

2012-05-01

The precise temperature for optimal neuroprotection in infants with neonatal encephalopathy is unclear. Our aim was to assess systemic effects of whole-body cooling to 35 °C, 33.5 °C, and 30 °C in a piglet model of perinatal asphyxia. Twenty-eight anesthetized male piglets aged <24 h underwent hypoxia-ischemia (HI) and were randomized to normothermia or cooling to rectal temperature (Trec) 35 °C, 33.5 °C, or 30 °C during 2-26 h after insult (n = 7 in each group). HR, MABP, and Trec were recorded continuously. Five animals cooled to 30 °C had fatal cardiac arrests. During 30 °C cooling, heart rate (HR) was lower vs. normothermia (P < 0.001). Although mean arterial blood pressure (MABP) did not vary between groups, more fluid boluses were needed at 30 °C than at normothermia (P < 0.02); dopamine use was higher at 30 °C than at normothermia or 35 °C (P = 0.005 and P = 0.02, respectively). Base deficit was increased at 30 °C at 12, 24, and 36 h vs. all other groups (P < 0.05), pH was acidotic at 36 h vs. normothermia (P = 0.04), and blood glucose was higher for the 30 °C group at 12 h vs. the normothermia and 35 °C groups (P < 0.05). Potassium was lower at 12 h in the 30 °C group vs. the 33.5 °C and 35 °C groups. There was no difference in cortisol level between groups. Cooling to 30 °C led to metabolic derangement and more cardiac arrests and deaths than cooling to 33.5 °C or 35 °C. Inadvertent overcooling should be avoided.

Routine sampling and the control of Legionella spp. in cooling tower water systems.

PubMed

Bentham, R H

2000-10-01

Cooling water samples from 31 cooling tower systems were cultured for Legionella over a 16-week summer period. The selected systems were known to be colonized by Legionella. Mean Legionella counts and standard deviations were calculated and time series correlograms prepared for each system. The standard deviations of Legionella counts in all the systems were very large, indicating great variability in the systems over the time period. Time series analyses demonstrated that in the majority of cases there was no significant relationship between the Legionella counts in the cooling tower at time of collection and the culture result once it was available. In the majority of systems (25/28), culture results from Legionella samples taken from the same systems 2 weeks apart were not statistically related. The data suggest that determinations of health risks from cooling towers cannot be reliably based upon single or infrequent Legionella tests.

Comparison of ground-coupled solar-heat-pump systems to conventional systems for residential heating, cooling and water heating

NASA Astrophysics Data System (ADS)

Choi, M. K.; Morehouse, J. H.; Hughes, P. J.

1981-07-01

An analysis is performed of ground-coupled stand-alone and series configured solar-assisted liquid-to-air heat pump systems for residences. The year-round thermal performance of these systems for space heating, space cooling, and water heating is determined by simulation and compared against non-ground-coupled solar heat pump systems as well as conventional heating and cooling systems in three geographic locations: Washington, DC; Fort Worth, Texas; and Madison, Wisconsin. The results indicate that without tax credits a combined solar/ground-coupled heat pump system for space heating and cooling is not cost competitive with conventional systems. Its thermal performance is considerably better than non-ground-coupled solar heat pumps in Fort Worth. Though the ground-coupled stand-alone heat pump provides 51 percent of the heating and cooling load with non-purchased energy in Fort Worth, its thermal performance in Washington and Madison is poor.

Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water.

PubMed

Chien, S H; Hsieh, M K; Li, H; Monnell, J; Dzombak, D; Vidic, R

2012-02-01

Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27,000 kJ∕h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 10(4) was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m∕s), and air mass velocity (3660 kg∕h m(2)), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality.

24 CFR 3280.714 - Appliances, cooling.

Code of Federal Regulations, 2013 CFR

2013-04-01

... refrigerating systems serving any air conditioning or comfort-cooling system installed in a manufactured home... Systems § 3280.714 Appliances, cooling. (a) Every air conditioning unit or a combination air conditioning... Conditioning and Air Source Unitary Heat Pump Equipment and certified by ARI or other nationally recognized...

24 CFR 3280.714 - Appliances, cooling.

Code of Federal Regulations, 2012 CFR

2012-04-01

... refrigerating systems serving any air conditioning or comfort-cooling system installed in a manufactured home... Systems § 3280.714 Appliances, cooling. (a) Every air conditioning unit or a combination air conditioning... Conditioning and Air Source Unitary Heat Pump Equipment and certified by ARI or other nationally recognized...

30 CFR 36.47 - Tests of exhaust-gas cooling system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... water consumption, high-water level when the system sprays excess water, and low-water level when the... cooling water shall be filled with the quantity of water recommended by the applicant. No cooling air... saturation, if this temperature is lower. (d) Water consumed in cooling the exhaust gas under the test...

User's manual for the BNW-I optimization code for dry-cooled power plants. [AMCIRC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braun, D.J.; Daniel, D.J.; De Mier, W.V.

1977-01-01

This appendix provides a listing, called Program AMCIRC, of the BNW-1 optimization code for determining, for a particular size power plant, the optimum dry cooling tower design using ammonia flow in the heat exchanger tubes. The optimum design is determined by repeating the design of the cooling system over a range of design conditions in order to find the cooling system with the smallest incremental cost. This is accomplished by varying five parameters of the plant and cooling system over ranges of values. These parameters are varied systematically according to techniques that perform pattern and gradient searches. The dry coolingmore » system optimized by program AMCIRC is composed of a condenser/reboiler (condensation of steam and boiling of ammonia), piping system (transports ammonia vapor out and ammonia liquid from the dry cooling towers), and circular tower system (vertical one-pass heat exchangers situated in circular configurations with cocurrent ammonia flow in the tubes of the heat exchanger). (LCL)« less

System design package for a solar heating and cooling system installed at Akron, Ohio

NASA Technical Reports Server (NTRS)

1979-01-01

Information used to evaluate the design of a solar heating, cooling, and domestic hot water system is given. A conventional heat pump provides summer cooling items as the design data brochure, system performance specification, system hazard analysis, spare parts list, and detailed design drawings. A solar system is installed in a single-family dwelling at Akron, Ohio, and at Duffield, Virginia.

Cooling systems of the resting area in free stall dairy barn

NASA Astrophysics Data System (ADS)

Calegari, F.; Calamari, L.; Frazzi, E.

2016-04-01

A study during the summer season evaluated the effect of different cooling systems on behavioral and productive responses of Italian Friesian dairy cows kept in an experimental-free stall barn located in the Po Valley in Italy. The study involved 30 lactating dairy cows subdivided into two groups kept in two pens with external hard court paddock in each free stall. The same cooling system was applied in the feeding area in both pens. A different cooling system in the resting area was applied to the two pens: in the pen SW, the resting area was equipped with fans and misters; in the other, there was simple ventilation (SV). Breathing rate, rectal temperature, milk yield, and milk characteristics (fat, protein, and somatic cell count) were measured. Behavioral activities (standing and lying cows in the different areas, as well as the animals in the feed bunk) were recorded. Mild to moderate heat waves during the trial were observed. On average, the breathing rate was numerically greater in SV compared with SW cows (60.2 and 55.8 breath/min, respectively), and mean rectal temperature remained below 39 °C in both groups during the trial (on average 38.7 and 38.8 °C in SV and SW, respectively. During the hotter periods of the trial, the time spent lying indoor in the free stall was greater in SW (11.8 h/day) than SV (10.7 h/day). Conversely, the time spent standing indoor without feeding was greater in SV (4.3 h/day) than SW (3.8 h/day). Milk yield was slightly better maintained during hotter period in SW compared with SV and somatic cell count was also slightly greater in the former. In conclusion, the adoption of the cooling system by means of evaporative cooling also in the resting area reduces the alteration of time budget caused by heat stress.

Natural circulating passive cooling system for nuclear reactor containment structure

DOEpatents

Gou, Perng-Fei; Wade, Gentry E.

1990-01-01

A passive cooling system for the contaminant structure of a nuclear reactor plant providing protection against overpressure within the containment attributable to inadvertent leakage or rupture of the system components. The cooling system utilizes natural convection for transferring heat imbalances and enables the discharge of irradiation free thermal energy to the atmosphere for heat disposal from the system.

Passive containment cooling water distribution device

DOEpatents

Conway, Lawrence E.; Fanto, Susan V.

1994-01-01

A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using a series of radial guide elements and cascading weir boxes to collect and then distribute the cooling water into a series of distribution areas through a plurality of cascading weirs. The cooling water is then uniformly distributed over the curved surface by a plurality of weir notches in the face plate of the weir box.

Hybrid Geothermal Heat Pumps for Cooling Telecommunications Data Centers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beckers, Koenraad J; Zurmuhl, David P.; Lukawski, Maciej Z.

The technical and economic performance of geothermal heat pump (GHP) systems supplying year-round cooling to representative small data centers with cooling loads less than 500 kWth were analyzed and compared to air-source heat pumps (ASHPs). A numerical model was developed in TRNSYS software to simulate the operation of air-source and geothermal heat pumps with and without supplementary air cooled heat exchangers - dry coolers (DCs). The model was validated using data measured at an experimental geothermal system installed in Ithaca, NY, USA. The coefficient of performance (COP) and cooling capacity of the GHPs were calculated over a 20-year lifetime andmore » compared to the performance of ASHPs. The total cost of ownership (TCO) of each of the cooling systems was calculated to assess its economic performance. Both the length of the geothermal borehole heat exchangers (BHEs) and the dry cooler temperature set point were optimized to minimize the TCO of the geothermal systems. Lastly, a preliminary analysis of the performance of geothermal heat pumps for cooling dominated systems was performed for other locations including Dallas, TX, Sacramento, CA, and Minneapolis, MN.« less

Megawatt Class Nuclear Space Power Systems (MCNSPS) conceptual design and evaluation report. Volume 1: Objectives, summary results and introduction

NASA Technical Reports Server (NTRS)

Wetch, J. R.

1988-01-01

The objective was to determine which reactor, conversion, and radiator technologies would best fulfill future Megawatt Class Nuclear Space Power System Requirements. Specifically, the requirement was 10 megawatts for 5 years of full power operation and 10 years systems life on orbit. A variety of liquid metal and gas cooled reactors, static and dynamic conversion systems, and passive and dynamic radiators were considered. Four concepts were selected for more detailed study. The concepts are: a gas cooled reactor with closed cycle Brayton turbine-alternator conversion with heat pipe and pumped tube-fin heat rejection; a lithium cooled reactor with a free piston Stirling engine-linear alternator and a pumped tube-fin radiator; a lithium cooled reactor with potassium Rankine turbine-alternator and heat pipe radiator; and a lithium cooled incore thermionic static conversion reactor with a heat pipe radiator. The systems recommended for further development to meet a 10 megawatt long life requirement are the lithium cooled reactor with the K-Rankine conversion and heat pipe radiator, and the lithium cooled incore thermionic reactor with heat pipe radiator.

Liquid metal cooled nuclear reactor plant system

DOEpatents

Hunsbedt, Anstein; Boardman, Charles E.

1993-01-01

A liquid metal cooled nuclear reactor having a passive cooling system for removing residual heat resulting for fuel decay during reactor shutdown, or heat produced during a mishap. The reactor system is enhanced with sealing means for excluding external air from contact with the liquid metal coolant leaking from the reactor vessel during an accident. The invention also includes a silo structure which resists attack by leaking liquid metal coolant, and an added unique cooling means.

Development of a thermoelectric cooling apparatus for high-voltage isoelectric focusing on a cellulose acetate membrane.

PubMed

Shiba, K; Toda, T; Iijima, S; Inoue, J; Yoshida, T; Cho, H; Kimura, M

1994-10-01

To develop an isoelectric focusing apparatus using a cellulose acetate membrane (Separax EF), we have designed a thermoelectric cooling isoelectric apparatus. This apparatus has two characteristics. Firstly, the cooling system was switched to a thermoelectric cooling system from an ice-cooling system. Secondly, the chamber lid of the electrophoretic apparatus was also devised so that samples could be applied without opening the chamber lid. With this apparatus we could perform the isoelectric focusing without worrying about room temperature and humidity in the laboratory. Applying 2000 V for an extra 5 min with our module cooling system, we achieved a much higher degree of resolution with three sheets of cellulose acetate membrane (Separax EF) overlaid for simultaneous electrophoresis. Thus, three types of information could be obtained from only one electrophoretic procedure.

Seismic Design of ITER Component Cooling Water System-1 Piping

NASA Astrophysics Data System (ADS)

Singh, Aditya P.; Jadhav, Mahesh; Sharma, Lalit K.; Gupta, Dinesh K.; Patel, Nirav; Ranjan, Rakesh; Gohil, Guman; Patel, Hiren; Dangi, Jinendra; Kumar, Mohit; Kumar, A. G. A.

2017-04-01

The successful performance of ITER machine very much depends upon the effective removal of heat from the in-vessel components and other auxiliary systems during Tokamak operation. This objective will be accomplished by the design of an effective Cooling Water System (CWS). The optimized piping layout design is an important element in CWS design and is one of the major design challenges owing to the factors of large thermal expansion and seismic accelerations; considering safety, accessibility and maintainability aspects. An important sub-system of ITER CWS, Component Cooling Water System-1 (CCWS-1) has very large diameter of pipes up to DN1600 with many intersections to fulfill the process flow requirements of clients for heat removal. Pipe intersection is the weakest link in the layout due to high stress intensification factor. CCWS-1 piping up to secondary confinement isolation valves as well as in-between these isolation valves need to survive a Seismic Level-2 (SL-2) earthquake during the Tokamak operation period to ensure structural stability of the system in the Safe Shutdown Earthquake (SSE) event. This paper presents the design, qualification and optimization of layout of ITER CCWS-1 loop to withstand SSE event combined with sustained and thermal loads as per the load combinations defined by ITER and allowable limits as per ASME B31.3, This paper also highlights the Modal and Response Spectrum Analyses done to find out the natural frequency and system behavior during the seismic event.

Combined cooling and purification system for nuclear reactor spent fuel pit, refueling cavity, and refueling water storage tank

DOEpatents

Corletti, M.M.; Lau, L.K.; Schulz, T.L.

1993-12-14

The spent fuel pit of a pressured water reactor (PWR) nuclear power plant has sufficient coolant capacity that a safety rated cooling system is not required. A non-safety rated combined cooling and purification system with redundant branches selectively provides simultaneously cooling and purification for the spent fuel pit, the refueling cavity, and the refueling water storage tank, and transfers coolant from the refueling water storage tank to the refueling cavity without it passing through the reactor core. Skimmers on the suction piping of the combined cooling and purification system eliminate the need for separate skimmer circuits with dedicated pumps. 1 figures.

Effect of a personal ambient ventilation system on physiological strain during heat stress wearing a ballistic vest.

PubMed

Hadid, A; Yanovich, R; Erlich, T; Khomenok, G; Moran, D S

2008-09-01

The present study was conducted in order to evaluate whether physiological strain is alleviated by a new personal cooling system (CS) consisting of a layered vest and integrated blower that generate a flow of air. Twelve male volunteers were exposed to climatic conditions of 40 degrees C, 40%RH (40/40), and 35 degrees C, 60%RH (35/60) during a 115 min exercise routine, followed by 70 min resting recovery, while wearing a battle dress uniform (BDU) and a ballistic vest, with (COOL) or without (NOCOOL) CS. The CS was able to attenuate the physiological strain levels during exercise, when compared to identical exposures without the CS. Temperature elevation, (DeltaT (re)) after 100 min of exercise, was lower by 0.26 +/- 0.20 and 0.34 +/- 0.21 degrees C in 40/40 and 35/60, respectively, (p < 0.05). Mean skin temperature (T(sk)) was lower by 0.9 +/- 0.4 and 0.6 +/- 0.5 degrees C for 40/40 and 35/60, respectively. Heart rate (HR) was not significantly different for COOL versus NOCOOL for 40/40. At 35/60, HR was lower by 10 beats per min (bpm) (p < 0.05). Physiological strain index (PSI) was 9 and 21% lower for the 40/40 and 35/60, respectively, for COOL versus NOCOOL (p < 0.05). Heat storage (S) rates were 19 and 24% lower and sweat rates were 21 and 25% lower for the 40/40 and 35/60, respectively, for COOL versus NOCOOL (p < 0.05). However, the CS was not effective in alleviating physiological strain during resting recovery with no difference in T (re) cooling rate, S, or HR drop rate between groups over resting recovery periods. The CS tested in this study was found to be an effective tool for lowering physiological strain while exercising but not during resting recovery. Therefore, the CS should be further developed in order to achieve greater attenuation of the thermal strain during exercise and improve effectiveness during rest. Overall, it has the potential to be useful for both military and sports personnel.

Electronic cooling design and test validation

NASA Astrophysics Data System (ADS)

Murtha, W. B.

1983-07-01

An analytical computer model has been used to design a counterflow air-cooled heat exchanger according to the cooling, structural and geometric requirements of a U.S. Navy shipboard electronics cabinet, emphasizing high reliability performance through the maintenance of electronic component junction temperatures lower than 110 C. Environmental testing of the design obtained has verified that the analytical predictions were conservative. Model correlation to the test data furnishes an upgraded capability for the evaluation of tactical effects, and has established a two-orders of magnitude growth potential for increased electronics capabilities through enhanced heat dissipation. Electronics cabinets of this type are destined for use with Vertical Launching System-type combatant vessel magazines.

Hot gas path component cooling system

DOEpatents

Lacy, Benjamin Paul; Bunker, Ronald Scott; Itzel, Gary Michael

2014-02-18

A cooling system for a hot gas path component is disclosed. The cooling system may include a component layer and a cover layer. The component layer may include a first inner surface and a second outer surface. The second outer surface may define a plurality of channels. The component layer may further define a plurality of passages extending generally between the first inner surface and the second outer surface. Each of the plurality of channels may be fluidly connected to at least one of the plurality of passages. The cover layer may be situated adjacent the second outer surface of the component layer. The plurality of passages may be configured to flow a cooling medium to the plurality of channels and provide impingement cooling to the cover layer. The plurality of channels may be configured to flow cooling medium therethrough, cooling the cover layer.

Temperature distribution of laser crystal in end-pumped DPSSL

NASA Astrophysics Data System (ADS)

Zheng, Yibo; Jia, Liping; Zhang, Lei; Wen, Jihua; Kang, Junjian

2009-11-01

The temperature distribution in different cooling system was studied. A thermal distribution model of laser crystal was established. Based on the calculation, the temperature distribution and deformation of ND:YVO4 crystal in different cooling system were obtained. When the pumping power is 2 W and the radius of pumping beams is 320μm, the temperature distribution and end face distortion of the laser crystal are lowest by using side directly hydrocooling method. The study shows that, the side directly hydrocooling method is a more efficient method to control the crystal temperature distribution and reduce the thermal effect.

Biofouling reduction in recirculating cooling systems through biofiltration of process water.

PubMed

Meesters, K P H; Van Groenestijn, J W; Gerritse, J

2003-02-01

Biofouling is a serious problem in industrial recirculating cooling systems. It damages equipment, through biocorrosion, and causes clogging and increased energy consumption, through decreased heat transfer. In this research a fixed-bed biofilter was developed which removed assimilable organic carbon (AOC) from process water, thus limiting the major substrate for the growth of biofouling. The biofilter was tested in a laboratory model recirculating cooling water system, including a heat exchanger and a cooling tower. A second identical model system without a biofilter served as a reference. Both installations were challenged with organic carbon (sucrose and yeast extract) to provoke biofouling. The biofilter improved the quality of the recirculating cooling water by reducing the AOC content, the ATP concentration, bacterial numbers (30-40 fold) and the turbidity (OD660). The process of biofouling in the heat exchangers, the process water pipelines and the cooling towers, was monitored by protein increase, heat transfer resistance, and chlorine demanded for maintenance. This revealed that biofouling was lower in the system with the biofilter compared to the reference installation. It was concluded that AOC removal through biofiltration provides an attractive, environmental-friendly means to reduce biofouling in industrial cooling systems.

Nuclear Power and the Environment.

ERIC Educational Resources Information Center

Dukert, Joseph M.

Described are the major environmental effects resulting from the production of electricity by nuclear power plants. Discussed are effects of waste heat, radioactivity, radioactive waste elimination, costs, and future prospects. Included are diagrams illustrating cooling tower operation, effects of thermal discharge into water systems, radioactive…

Transient Three-Dimensional Analysis of Nozzle Side Load in Regeneratively Cooled Engines

NASA Technical Reports Server (NTRS)

Wang, Ten-See

2005-01-01

Three-dimensional numerical investigations on the start-up side load physics for a regeneratively cooled, high-aspect-ratio nozzle were performed. The objectives of this study are to identify the three-dimensional side load physics and to compute the associated aerodynamic side load using an anchored computational methodology. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and a transient inlet condition based on an engine system simulation. Computations were performed for both the adiabatic and cooled walls in order to understand the effect of boundary conditions. Finite-rate chemistry was used throughout the study so that combustion effect is always included. The results show that three types of shock evolution are responsible for side loads: generation of combustion wave; transitions among free-shock separation, restricted-shock separation, and simultaneous free-shock and restricted shock separations; along with oscillation of shocks across the lip. Wall boundary conditions drastically affect the computed side load physics: the adiabatic nozzle prefers free-shock separation while the cooled nozzle favors restricted-shock separation, resulting in higher peak side load for the cooled nozzle than that of the adiabatic nozzle. By comparing the computed physics with those of test observations, it is concluded that cooled wall is a more realistic boundary condition, and the oscillation of the restricted-shock separation flow pattern across the lip along with its associated tangential shock motion are the dominant side load physics for a regeneratively cooled, high aspect-ratio rocket engine.

Integrated application of combined cooling, heating and power poly-generation PV radiant panel system of zero energy buildings

NASA Astrophysics Data System (ADS)

Yin, Baoquan

2018-02-01

A new type of combined cooling, heating and power of photovoltaic radiant panel (PV/R) module was proposed, and applied in the zero energy buildings in this paper. The energy system of this building is composed of PV/R module, low temperature difference terminal, energy storage, multi-source heat pump, energy balance control system. Radiant panel is attached on the backside of the PV module for cooling the PV, which is called PV/R module. During the daytime, the PV module was cooled down with the radiant panel, as the temperature coefficient influence, the power efficiency was increased by 8% to 14%, the radiant panel solar heat collecting efficiency was about 45%. Through the nocturnal radiant cooling, the PV/R cooling capacity could be 50 W/m2. For the multifunction energy device, the system shows the versatility during the heating, cooling and power used of building utilization all year round.

Optimization and Simulation of Plastic Injection Process using Genetic Algorithm and Moldflow

NASA Astrophysics Data System (ADS)

Martowibowo, Sigit Yoewono; Kaswadi, Agung

2017-03-01

The use of plastic-based products is continuously increasing. The increasing demands for thinner products, lower production costs, yet higher product quality has triggered an increase in the number of research projects on plastic molding processes. An important branch of such research is focused on mold cooling system. Conventional cooling systems are most widely used because they are easy to make by using conventional machining processes. However, the non-uniform cooling processes are considered as one of their weaknesses. Apart from the conventional systems, there are also conformal cooling systems that are designed for faster and more uniform plastic mold cooling. In this study, the conformal cooling system is applied for the production of bowl-shaped product made of PP AZ564. Optimization is conducted to initiate machine setup parameters, namely, the melting temperature, injection pressure, holding pressure and holding time. The genetic algorithm method and Moldflow were used to optimize the injection process parameters at a minimum cycle time. It is found that, an optimum injection molding processes could be obtained by setting the parameters to the following values: T M = 180 °C; P inj = 20 MPa; P hold = 16 MPa and t hold = 8 s, with a cycle time of 14.11 s. Experiments using the conformal cooling system yielded an average cycle time of 14.19 s. The studied conformal cooling system yielded a volumetric shrinkage of 5.61% and the wall shear stress was found at 0.17 MPa. The difference between the cycle time obtained through simulations and experiments using the conformal cooling system was insignificant (below 1%). Thus, combining process parameters optimization and simulations by using genetic algorithm method with Moldflow can be considered as valid.

Counter-extrapolation method for conjugate interfaces in computational heat and mass transfer.

PubMed

Le, Guigao; Oulaid, Othmane; Zhang, Junfeng

2015-03-01

In this paper a conjugate interface method is developed by performing extrapolations along the normal direction. Compared to other existing conjugate models, our method has several technical advantages, including the simple and straightforward algorithm, accurate representation of the interface geometry, applicability to any interface-lattice relative orientation, and availability of the normal gradient. The model is validated by simulating the steady and unsteady convection-diffusion system with a flat interface and the steady diffusion system with a circular interface, and good agreement is observed when comparing the lattice Boltzmann results with respective analytical solutions. A more general system with unsteady convection-diffusion process and a curved interface, i.e., the cooling process of a hot cylinder in a cold flow, is also simulated as an example to illustrate the practical usefulness of our model, and the effects of the cylinder heat capacity and thermal diffusivity on the cooling process are examined. Results show that the cylinder with a larger heat capacity can release more heat energy into the fluid and the cylinder temperature cools down slower, while the enhanced heat conduction inside the cylinder can facilitate the cooling process of the system. Although these findings appear obvious from physical principles, the confirming results demonstrates the application potential of our method in more complex systems. In addition, the basic idea and algorithm of the counter-extrapolation procedure presented here can be readily extended to other lattice Boltzmann models and even other computational technologies for heat and mass transfer systems.