Experimental evaluation of cooling efficiency of the high performance cooling device

NASA Astrophysics Data System (ADS)

Nemec, Patrik; Malcho, Milan

2016-06-01

This work deal with experimental evaluation of cooling efficiency of cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description of cooling device, working principle of cooling device, construction of cooling device. Experimental part describe the measuring method of device cooling efficiency evaluation. The work results are presented in graphic visualization of temperature dependence of the contact area surface between cooling device evaporator and electronic components on the loaded heat of electronic components in range from 250 to 740 W and temperature dependence of the loop thermosiphon condenser surface on the loaded heat of electronic components in range from 250 to 740 W.

Method of energy load management using PCM for heating and cooling of buildings

DOEpatents

Stovall, T.K.; Tomlinson, J.J.

1996-03-26

A method is described for energy load management for the heating and cooling of a building. The method involves utilizing a wallboard as a portion of the building, the wallboard containing about 5 to about 30 wt.% phase change material such that melting of the phase change material occurs during a rise in temperature within the building to remove heat from the air, and a solidification of the phase change material occurs during a lowering of the temperature to dispense heat into the air. At the beginning of either of these cooling or heating cycles, the phase change material is preferably ``fully charged``. In preferred installations one type of wallboard is used on the interior surfaces of exterior walls, and another type as the surface on interior walls. The particular PCM is chosen for the desired wall and room temperature of these locations. In addition, load management is achieved by using PCM-containing wallboards that form cavities of the building such that the cavities can be used for the air handling duct and plenum system of the building. Enhanced load management is achieved by using a thermostat with reduced dead band of about the upper half of a normal dead band of over three degrees. In some applications, air circulation at a rate greater than normal convection provides additional comfort. 7 figs.

Method of energy load management using PCM for heating and cooling of buildings

DOEpatents

Stovall, Therese K.; Tomlinson, John J.

1996-01-01

A method of energy load management for the heating and cooling of a building. The method involves utilizing a wallboard as a portion of the building, the wallboard containing about 5 to about 30 wt. % a phase change material such that melting of the phase change material occurs during a rise in temperature within the building to remove heat from the air, and a solidification of the phase change material occurs during a lowering of the temperature to dispense heat into the air. At the beginning of either of these cooling or heating cycles, the phase change material is preferably "fully charged". In preferred installations one type of wallboard is used on the interior surfaces of exterior walls, and another type as the surface on interior walls. The particular PCM is chosen for the desired wall and room temperature of these locations. In addition, load management is achieved by using PCM-containing wallboard that form cavities of the building such that the cavities can be used for the air handling duct and plenum system of the building. Enhanced load management is achieved by using a thermostat with reduced dead band of about the upper half of a normal dead band of over three degree. In some applications, air circulation at a rate greater than normal convection provides additional comfort.

Method of energy load management using PCM for heating and cooling of buildings

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

Stovall, T.K.; Tomlinson, J.J.

1996-03-26

A method is described for energy load management for the heating and cooling of a building. The method involves utilizing a wallboard as a portion of the building, the wallboard containing about 5 to about 30 wt.% phase change material such that melting of the phase change material occurs during a rise in temperature within the building to remove heat from the air, and a solidification of the phase change material occurs during a lowering of the temperature to dispense heat into the air. At the beginning of either of these cooling or heating cycles, the phase change material ismore » preferably ``fully charged``. In preferred installations one type of wallboard is used on the interior surfaces of exterior walls, and another type as the surface on interior walls. The particular PCM is chosen for the desired wall and room temperature of these locations. In addition, load management is achieved by using PCM-containing wallboards that form cavities of the building such that the cavities can be used for the air handling duct and plenum system of the building. Enhanced load management is achieved by using a thermostat with reduced dead band of about the upper half of a normal dead band of over three degrees. In some applications, air circulation at a rate greater than normal convection provides additional comfort. 7 figs.« less

Decommissioning of magnox Ltd fuel cooling pond facilities in the UK

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

Bertoncini, Carlo

2013-07-01

Magnox reactors were the first generation of nuclear power stations built in the UK; ten sites in total, of which, nine had wet fuel routes with cooling ponds. Five ponds are currently in a decommissioning phase; this paper will focus primarily on Hunterston-A (HNA) Site and the central programme of work which governs its management. During its operation, the Cartridge Cooling Pond at HNA was used to receive the spent fuel discharged from the Site's two reactors, it was then stored for cooling purposes prior to dispatch off site. The current decommissioning phase focusses on draining the 6500 m{sup 3}more » pond. Due to the Site's limited caesium removal facilities, a stand-alone effluent treatment plant was constructed to improve abatement and reduce the pond activity from 200 to 0.7 Bq/ml (β). This was necessary due to increased environmental standards introduced since the site had ceased generation ten years previously. Early characterisation and experience from other sites concluded that if the pond were to be drained without any treatment to the walls, doses to the Operators, during subsequent decommissioning works, would routinely be in excess of 1 mSv.hr{sup -1}(γ). An opportunity was realised within the Ponds Programme that if the surface layer of the pond walls were to be removed during drain-down, ambient dose rates would be reduced by a factor of 10; this would allow for more cost-effective decommissioning options in the future. Ultrahigh pressure water jetting was tested and proved to yield a ∼95% total-activity reduction on treated surfaces. Challenges were overcome in providing safe and secure access to Decommissioning Operators to perform this operation by means of floating platforms on the surface of the pond. As strategies to clear facilities to exemption levels are becoming both cost prohibitive and not reasonably practicable, work is now underway in the Programme to determine the optimum condition for entry into long-term quiescent storage

Transient Load Following and Control Analysis of Advanced S-CO2 Power Conversion with Dry Air Cooling

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

Moisseytsev, Anton; Sienicki, James J.

2016-01-01

Supercritical carbon dioxide (S-CO2) Brayton cycles are under development as advanced energy converters for advanced nuclear reactors, especially the Sodium-Cooled Fast Reactor (SFR). The use of dry air cooling for direct heat rejection to the atmosphere ultimate heat sink is increasingly becoming a requirement in many regions due to restrictions on water use. The transient load following and control behavior of an SFR with an S-CO2 cycle power converter utilizing dry air cooling have been investigated. With extension and adjustment of the previously existing control strategy for direct water cooling, S-CO2 cycle power converters can also be used for loadmore » following operation in regions where dry air cooling is a requirement« less

Dielectric-loaded waveguide circulator for cryogenically cooled and cascaded maser waveguide structures

NASA Technical Reports Server (NTRS)

Clauss, R. C.; Quinn, R. B. (Inventor)

1980-01-01

A dielectrically loaded four port waveguide circulator is used with a reflected wave maser connected to a second port between first and third ports to form one of a plurality of cascaded maser waveguide structures. The fourth port is connected to a waveguide loaded with microwave energy absorbing material. The third (output signal) port of one maser waveguide structure is connected by a waveguide loaded with dielectric material to the first (input) port of an adjacent maser waveguide structure, and the second port is connected to a reflected wave maser by a matching transformer which passes the signal to be amplified into and out of the reflected wavemaser and blocks pumping energy in the reflected wave maser from entering the circulator. A number of cascaded maser waveguide structures are thus housed in a relatively small volume of conductive material placed within a cryogenically cooled magnet assembly.

Can storage reduce electricity consumption? A general equation for the grid-wide efficiency impact of using cooling thermal energy storage for load shifting

NASA Astrophysics Data System (ADS)

Deetjen, Thomas A.; Reimers, Andrew S.; Webber, Michael E.

2018-02-01

This study estimates changes in grid-wide, energy consumption caused by load shifting via cooling thermal energy storage (CTES) in the building sector. It develops a general equation for relating generator fleet fuel consumption to building cooling demand as a function of ambient temperature, relative humidity, transmission and distribution current, and baseline power plant efficiency. The results present a graphical sensitivity analysis that can be used to estimate how shifting load from cooling demand to cooling storage could affect overall, grid-wide, energy consumption. In particular, because power plants, air conditioners and transmission systems all have higher efficiencies at cooler ambient temperatures, it is possible to identify operating conditions such that CTES increases system efficiency rather than decreasing it as is typical for conventional storage approaches. A case study of the Dallas-Fort Worth metro area in Texas, USA shows that using CTES to shift daytime cooling load to nighttime cooling storage can reduce annual, system-wide, primary fuel consumption by 17.6 MWh for each MWh of installed CTES capacity. The study concludes that, under the right circumstances, cooling thermal energy storage can reduce grid-wide energy consumption, challenging the perception of energy storage as a net energy consumer.

Heat load studies of a water-cooled minichannel monochromator for synchrotron x-ray beams

NASA Astrophysics Data System (ADS)

Freund, Andreas K.; Arthur, John R.; Zhang, Lin

1997-12-01

We fabricated a water-cooled silicon monochromator crystal with small channels for the special case of a double-crystal fixed-exit monochromator design where the beam walks across the crystal when the x-ray energy is changed. The two parts of the cooled device were assembled using a new technique based on low melting point solder. The bending of the system produced by this technique could be perfectly compensated by mechanical counter-bending. Heat load tests of the monochromator in a synchrotron beam of 75 W total power, 3 mm high and 15 mm wide, generated by a multipole wiggler at SSRL, showed that the thermal slope error of the crystal is 1 arcsec/40 W power, in full agreement with finite element analysis. The cooling scheme is adequate for bending magnet beamlines at the ESRF and present wiggler beamlines at the SSRL.

Effects of micro electric current load during cooling of plant tissues on intracellular ice crystal formation behavior and pH.

PubMed

Ninagawa, Takako; Kawamura, Yukio; Konishi, Tadashi; Narumi, Akira

2016-08-01

Cryopreservation techniques are expected to evolve further to preserve biomaterials and foods in a fresh state for extended periods of time. Long-term cryopreservation of living materials such as food and biological tissue is generally achieved by freezing; thus, intracellular freezing occurs. Intracellular freezing injures the cells and leads to cell death. Therefore, a dream cryopreservation technique would preserve the living materials without internal ice crystal formation at a temperature low enough to prevent bacterial activity. This study was performed to investigate the effect of micro electrical current loading during cooling as a new cryopreservation technique. The behavior of intracellular ice crystal formation in plant tissues with or without an electric current load was evaluated using the degree of supercooling, degree of cell deformation, and grain size and growing rate of intracellular ice crystal. Moreover, the transition of intracellular pH during plant tissue cooling with or without electric current loading was also examined using the fluorescence intensity ratio to comprehend cell activity at lower temperatures. The results indicated that micro electric current load did not only decrease the degree of cell deformation and grain size of intracellular ice crystal but also reduced the decline in intracellular pH due to temperature lowering, compared with tissues subjected to the same cooling rate without an electric current load. Thus, the effect of electric current load on cryopreservation and the potential of a new cryopreservation technique using electric current load were discussed based on these results. Copyright © 2016 Elsevier Inc. All rights reserved.

High resolution in-line analyses of precipitation at two UK ground locations, and possible relevance to convective cooling at cloud level.

NASA Astrophysics Data System (ADS)

Durham, Brian

2015-04-01

Wet deposition of many molecular pollutants can be simulated `sufficiently well' by a simple meteorological model, including the poorly soluble ozone (Tost et al, 2007, 2754). Carbon dioxide (CO2) has a Henry constant similar to that of ozone, but perhaps because its boundary layer presence is three orders of magnitude greater than ozone it has been widely assumed to be immune to significant cleansing by scavenging and deposition. In 2009 this `elephant' was approached (cautiously!) at the first of two UK locations using high time-resolution analyses of delivered rainwater, and some initial observations seem relevant to the `organised convection' theme of the present session. Six variables are measured every second, averaged every 60 seconds, including: conductivity; acidity ([H3O+] = 10 ^-pH ) and; stripped CO2 (by NDIRS). Convective precipitation typically delivers significantly more CO2 than predicted from Henry's Law, is supersaturated on arrival and shows a characteristic `spiky' profile against time. In assessing the above, this paper revisits eighty years of measurements of the Henry's Law equilibrium for the CO2/water system at partial pressures less than 1 atmosphere, and (more recently) low-pressure solubility at temperatures down to 4°C (Carroll, Slupski and Mather, 1991, 1203; Faraday Discuss. 2013, 167, 462-3). The observed solute load and supersaturation would become plausible if the reported upturn in solubility between 20°C and 4°C continued into the super-cooled zone. In a cloud, super-cooling will arise under convection when condensing droplets are chilled by adiabatic expansion of the carrier air. Droplets will increase in molar volume by up to 2.5% at -34°C (the temperature of spontaneous ice nucleation, Hare and Sorensen, 1987), offering a physical framework for the observed characteristics, and the possibility that `spikiness' reflects the degree of organisation of convection.

Building and environmental factors that influence bacterial and fungal loading on air conditioning cooling coils.

PubMed

Bakker, A; Siegel, J A; Mendell, M J; Peccia, J

2018-05-30

We investigated bacterial and fungal concentrations on cooling coils of commercial AC units and quantified associations between microbial loads and AC unit or building operational parameters. A field campaign was conducted to sample 25 AC units in the humid, subtropical climate of Southern CT, USA and 15 AC units in the hot-summer Mediterranean climate of Sacramento, CA, USA. Median concentrations (with interquartile range) of bacteria and fungi on the cooling coils were 1.2 × 10 7 (5.1 × 10 6 -3.9 × 10 7 ) cells/m 2 and 7.6 × 10 5 (5.6 × 10 4 -4.4 × 10 6 ) spore equivalents (SE)/m 2 , respectively. Concentrations varied among units with median unit concentrations ranging three orders of magnitude for bacteria and seven orders of magnitude for fungi. Controlled comparisons and multivariable regressions indicate that dominant factors associated with AC coil loading include the nominal efficiency of upstream filters (P = .008 for bacteria and P < .001 for fungi) and coil moisture, which was reflected in fungal loading differences between top and bottom halves of the AC coils in Southern CT (P = .05) and the dew points of the two climates considered (P = .04). Environmental and building characteristics explained 42% (P < .001) of bacterial concentration variability and 66% (P < .001) of fungal concentration variability among samples. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Cooling system for superconducting magnet

DOEpatents

Gamble, Bruce B.; Sidi-Yekhlef, Ahmed

1998-01-01

A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir.

Cooling system for superconducting magnet

DOEpatents

Gamble, B.B.; Sidi-Yekhlef, A.

1998-12-15

A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir. 3 figs.

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.

Defining the market for gas cooling--

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

Brodrick, J.R.; Patel, R.

1990-01-01

This paper looks at the market prospects for emerging gas cooling technologies. Many factors are found influence market decisions, and a number of factors have been set aside for reasons of conservatism and expediency. By considering some of these motivators, a fuller understanding of the market is made. Relative to this information, the potential success of gas cooling systems are estimated. Three gas cooling systems are evaluated as possible approaches for base-loaded and peak-loaded commercial buildings. Other system concepts may be appropriate.

Stratospheric Cooling and Arctic Ozone Recovery

NASA Technical Reports Server (NTRS)

Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.

1998-01-01

We present sensitivity studies using the AER( box model for an idealized parcel in the lower stratosphere at 70 N during winter/spring with different assumed stratospheric coolings and chlorine loadings. Our calculations show that stratospheric cooling could further deplete ozone via increased polar stratospheric cloud (PSC) formation and retard its expected recovery even with the projected chlorine loading decrease. We introduce the concept of chlorine-cooling equivalent and show that a 1 K cooling could provide the same local ozone depletion as an increase of chlorine by 0.4-0.7 ppbv for the scenarios considered. Thus, sustained stratospheric cooling could further reduce Arctic ozone content and delay the anticipated ozone recovery in the Northern Hemisphere even with the realization of the Montreal Protocol and its Amendments.

Stratospheric Cooling and Arctic Ozone Recovery

NASA Technical Reports Server (NTRS)

Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriquez, Jose M.

1998-01-01

We present sensitivity studies using the AER box model for an idealized parcel in the lower stratosphere at 70 deg N during winter/spring with different assumed stratospheric cooling and chlorine loadings. Our calculations show that stratospheric cooling could further deplete ozone via increased polar stratospheric cloud (PSC) formation and retard its expected recovery even with the projected chlorine loading decrease. We introduce the concept of chlorine-cooling equivalent and show that a 1 K Cooling could provide the same local ozone depletion as an increase of chlorine by 0.4-0.7 ppbv for the scenarios considered. Thus, sustained stratospheric cooling could further reduce Arctic ozone content and delay the anticipated ozone recovery in the Northern Hemisphere even with the realization of the Montreal Protocol and its Amendments.

Performance comparison of single-stage mixed-refrigerant Joule-Thomson cycle and reverse Brayton cycle for cooling 80 to 120 K temperature-distributed heat loads

NASA Astrophysics Data System (ADS)

Wang, H. C.; Chen, G. F.; Gong, M. Q.; Li, X.

2017-12-01

Thermodynamic performance comparison of single-stage mixed-refrigerant Joule-Thomson cycle (MJTR) and pure refrigerant reverse Brayton cycle (RBC) for cooling 80 to 120 K temperature-distributed heat loads was conducted in this paper. Nitrogen under various liquefaction pressures was employed as the heat load. The research was conducted under nonideal conditions by exergy analysis methods. Exergy efficiency and volumetric cooling capacity are two main evaluation parameters. Exergy loss distribution in each process of refrigeration cycle was also investigated. The exergy efficiency and volumetric cooling capacity of MJTR were obviously superior to RBC in 90 to 120 K temperature zone, but still inferior to RBC at 80 K. The performance degradation of MJTR was caused by two main reasons: The high fraction of neon resulted in large entropy generation and exergy loss in throttling process. Larger duty and WLMTD lead to larger exergy losses in recuperator.

The Damaging Effects of Earthquake Excitation on Concrete Cooling Towers

NASA Astrophysics Data System (ADS)

Abedi-Nik, Farhad; Sabouri-Ghomi, Saeid

2008-07-01

Reinforced concrete cooling towers of hyperbolic shell configuration find widespread application in utilities engaged in the production of electric power. In design of critical civil infrastructure of this type, it is imperative to consider all the possible loading conditions that the cooling tower may experience, an important loading condition in many countries is that of the earthquake excitation, whose influence on the integrity and stability of cooling towers is profound. Previous researches have shown that the columns supporting a cooling tower are sensitive to earthquake forces, as they are heavily loaded elements that do not possess high ductility, and understanding the behavior of columns under earthquake excitation is vital in structural design because they provide the load path for the self weight of the tower shell. This paper presents the results of a finite element investigation of a representative "dry" cooling tower, using realistic horizontal and vertical acceleration data obtained from the recent and widely-reported Tabas, Naghan and Bam earthquakes in Iran. The results of both linear and nonlinear analyses are reported in the paper, the locations of plastic hinges within the supporting columns are identified and the ramifications of the plastic hinges on the stability of the cooling tower are assessed. It is concluded that for the (typical) cooling tower configuration analyzed, the columns that are instrumental in providing a load path are influenced greatly by earthquake loading, and for the earthquake data used in this study the representative cooling tower would be rendered unstable and would collapse under the earthquake forces considered.

The Damaging Effects of Earthquake Excitation on Concrete Cooling Towers

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

Abedi-Nik, Farhad; Sabouri-Ghomi, Saeid

2008-07-08

Reinforced concrete cooling towers of hyperbolic shell configuration find widespread application in utilities engaged in the production of electric power. In design of critical civil infrastructure of this type, it is imperative to consider all the possible loading conditions that the cooling tower may experience, an important loading condition in many countries is that of the earthquake excitation, whose influence on the integrity and stability of cooling towers is profound. Previous researches have shown that the columns supporting a cooling tower are sensitive to earthquake forces, as they are heavily loaded elements that do not possess high ductility, and understandingmore » the behavior of columns under earthquake excitation is vital in structural design because they provide the load path for the self weight of the tower shell. This paper presents the results of a finite element investigation of a representative 'dry' cooling tower, using realistic horizontal and vertical acceleration data obtained from the recent and widely-reported Tabas, Naghan and Bam earthquakes in Iran. The results of both linear and nonlinear analyses are reported in the paper, the locations of plastic hinges within the supporting columns are identified and the ramifications of the plastic hinges on the stability of the cooling tower are assessed. It is concluded that for the (typical) cooling tower configuration analyzed, the columns that are instrumental in providing a load path are influenced greatly by earthquake loading, and for the earthquake data used in this study the representative cooling tower would be rendered unstable and would collapse under the earthquake forces considered.« less

Solar thermal heating and cooling. A bibliography with abstracts

NASA Technical Reports Server (NTRS)

Arenson, M.

1979-01-01

This bibliographic series cites and abstracts the literature and technical papers on the heating and cooling of buildings with solar thermal energy. Over 650 citations are arranged in the following categories: space heating and cooling systems; space heating and cooling models; building energy conservation; architectural considerations, thermal load computations; thermal load measurements, domestic hot water, solar and atmospheric radiation, swimming pools; and economics.

Calculation of the Thermal Resistance of a Heat Distributer in the Cooling System of a Heat-Loaded Element

NASA Astrophysics Data System (ADS)

Vasil'ev, E. N.

2018-04-01

Numerical simulation is performed for heat transfer in a heat distributer of a thermoelectric cooling system, which is located between the heat-loaded element and the thermoelectric module, for matching their sizes and for heat flux equalization. The dependences of the characteristic values of temperature and thermal resistance of the copper and aluminum heat distributer on its thickness and on the size of the heatloaded element. Comparative analysis is carried out for determining the effect of the thermal conductivity of the material and geometrical parameters on the heat resistance. The optimal thickness of the heat distributer depending on the size of the heat-loaded element is determined.

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.

Solar heating and cooling system installed at Leavenworth, Kansas

NASA Technical Reports Server (NTRS)

1980-01-01

A solar heating and cooling is described which is designed to furnish 90 percent of the overall heating load, 70 percent of the cooling load and 100 percent of the domestic hot water load. The building has two floors with a total of 12,000 square feet gross area. The system has 120 flat-plate liquid solar panels with a net area of 2,200 square feet. Five 3 ton Arkla solar assisted absorption units provide the cooling, in conjunction with a 3,000 gallon chilled water storage tank. Two 3,000 gallon storage tanks are provided with one designated for summer use, whereas both tanks are utilized during winter.

Stratospheric Cooling and Arctic Ozone Recovery. Appendix L

NASA Technical Reports Server (NTRS)

Danilin, Michael Y.; Sze, Nien-Dak; Ko, Malcolm K. W.; Rodriguez, Jose M.; Tabazadeh, Azadeh

1998-01-01

We present sensitivity studies using the AER box model for an idealized parcel in the lower stratosphere at 70 deg N during winter/spring with different assumed stratospheric cooling and chlorine loadings. Our calculations show that stratospheric cooling could further deplete ozone via increased polar stratospheric cloud (PSC) formation and retard its expected recovery even with the projected chlorine loading decrease. We introduce the concept of chlorine-cooling equivalent and show that a 1 K cooling could provide the same local ozone depletion as an increase of chlorine by 0.4 - 0.7 ppbv for the scenarios considered. Thus, sustained stratospheric cooling could further reduce Arctic ozone content and delay the anticipated ozone recovery in the Northern Hemisphere even with the realization of the Montreal Protocol and its Amendments.

Failure study of helium-cooled tungsten divertor plasma-facing units tested at DEMO relevant steady-state heat loads

NASA Astrophysics Data System (ADS)

Ritz, G.; Hirai, T.; Norajitra, P.; Reiser, J.; Giniyatulin, R.; Makhankov, A.; Mazul, I.; Pintsuk, G.; Linke, J.

2009-12-01

Tungsten was selected as armor material for the helium-cooled divertor in future DEMO-type fusion reactors and fusion power plants. After realizing the design and testing of them under cyclic thermal loads of up to ~14 MW m-2, the tungsten divertor plasma-facing units were examined by metallography; they revealed failures such as cracks at the thermal loaded and as-machined surfaces, as well as degradation of the brazing layers. Furthermore, in order to optimize the machining processes, the quality of tungsten surfaces prepared by turning, milling and using a diamond cutting wheel were examined. This paper presents a metallographic examination of the tungsten plasma-facing units as well as technical studies and the characterization on machining of tungsten and alternative brazing joints.

Systematic optimization of laser cooling of dysprosium

NASA Astrophysics Data System (ADS)

Mühlbauer, Florian; Petersen, Niels; Baumgärtner, Carina; Maske, Lena; Windpassinger, Patrick

2018-06-01

We report on an apparatus for cooling and trapping of neutral dysprosium. We characterize and optimize the performance of our Zeeman slower and 2D molasses cooling of the atomic beam by means of Doppler spectroscopy on a 136 kHz broad transition at 626 nm. Furthermore, we demonstrate the characterization and optimization procedure for the loading phase of a magneto-optical trap (MOT) by increasing the effective laser linewidth by sideband modulation. After optimization of the MOT compression phase, we cool and trap up to 10^9 atoms within 3 seconds in the MOT at temperatures of 9 μK and phase space densities of 1.7 \\cdot 10^{-5}, which constitutes an ideal starting point for loading the atoms into an optical dipole trap and for subsequent forced evaporative cooling.

Phase change based cooling for high burst mode heat loads with temperature regulation above the phase change temperature

DOEpatents

The United States of America as represented by the United States Department of Energy

2009-12-15

An apparatus and method for transferring thermal energy from a heat load is disclosed. In particular, use of a phase change material and specific flow designs enables cooling with temperature regulation well above the fusion temperature of the phase change material for medium and high heat loads from devices operated intermittently (in burst mode). Exemplary heat loads include burst mode lasers and laser diodes, flight avionics, and high power space instruments. Thermal energy is transferred from the heat load to liquid phase change material from a phase change material reservoir. The liquid phase change material is split into two flows. Thermal energy is transferred from the first flow via a phase change material heat sink. The second flow bypasses the phase change material heat sink and joins with liquid phase change material exiting from the phase change material heat sink. The combined liquid phase change material is returned to the liquid phase change material reservoir. The ratio of bypass flow to flow into the phase change material heat sink can be varied to adjust the temperature of the liquid phase change material returned to the liquid phase change material reservoir. Varying the flowrate and temperature of the liquid phase change material presented to the heat load determines the magnitude of thermal energy transferred from the heat load.

District heating and cooling feasibility study, Dunkirk, New York

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

Not Available

The objective of this project is to perform a preliminary investigation of the technical and economic feasibility of implementing a district heating and cooling (DHC) system in the City of Dunkirk, New York. The study was conducted by first defining a heating and cooling (HC) load service area. Then, questionnaires were sent to prospective DHC customers. After reviewing the owners responses, large consumers of energy were interviewed for more detail of their HC systems, including site visits, to determine possibilities of retrofitting their systems to district heating and cooling. Peak HC loads for the buildings were estimated by Burns andmore » Roe's in-house computer programs. Based on the peak loads, certain customers were determined for suitability as anchor customers. Various options using cogeneration were investigated for possible HC sources. Equipment for HC sources and HC loads were sized and their associated costs estimated. Finally, economic analyses were performed. The conclusion is that it is technically and economically feasible to implement a district heating and cooling system in the City of Dunkirk. 14 figs., 15 tabs.« less

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

A fuselage/tank structure study for actively cooled hypersonic cruise vehicles: Active cooling system analysis

NASA Technical Reports Server (NTRS)

Stone, J. E.

1975-01-01

The effects of fuselage cross section and structural arrangement on the performance of actively cooled hypersonic cruise vehicles are investigated. An active cooling system which maintains the aircraft's entire surface area at temperatures below 394 K at Mach 6 is developed along with a hydrogen fuel tankage thermal protection system. Thermodynamic characteristics of the actively cooled thermal protection systems established are summarized. Design heat loads and coolant flowrate requirements are defined for each major structural section and for the total system. Cooling system weights are summarized at the major component level. Conclusions and recommendations are included.

Solar-heated and cooled savings and loan building-1-Leavenworth, Kanasas

NASA Technical Reports Server (NTRS)

1981-01-01

Report describes heating and cooling system which furnishes 90 percent of annual heating load, 70 percent of cooling load, and all hot water for two-story building. Roof-mounted flat-plate collectors allow three distinct flow rates and are oriented south for optimum energy collection. Building contains fully automated temperature controls is divided into five temperature-load zones, each with independent heat pump.

Back to the Basics: Cooling with Ice.

ERIC Educational Resources Information Center

Estes, R. C.

1979-01-01

A new high school shifts an electrical demand charge load by using an icemaker during nonoperating hours to provide chilled water for producing cool air. A review resulted in a computer being placed in the design to control the electrical demand charge load in addition to spreading the load. (Author/MLF)

First wall structural analysis of the aqueous self-cooled blanket concept

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

O'Brien, D.A.; Steiner, D.; Embrechts, M.J.

1986-11-01

A recently proposed blanket concept using water coolant with dissolved lithium compounds for breeding employs water cooled first walls. Water cooled first walls for blankets have also been proposed for some solid breeder blankets. Design options for water cooled first walls are examined in this paper. Four geometries and three materials are analyzed for water coolant at 300/sup 0/C and 13.8 MPa (2000 psi). Maximum neutron wall loads (with surface heat loads being 25% of neutron wall load) are determined for each geometry and material combination. Of the materials studied, only vanadium alloy is found to be capable of withstandingmore » high wall loads (>10MW/m/sup 2/ neutron and >2.5 MW/m/sup 2/ heat).« less

Optimization of thermoelectric cooling regimes for heat-loaded elements taking into account the thermal resistance of the heat-spreading system

NASA Astrophysics Data System (ADS)

Vasil'ev, E. N.

2017-09-01

A mathematical model has been proposed for analyzing and optimizing thermoelectric cooling regimes for heat-loaded elements of engineering and electronic devices. The model based on analytic relations employs the working characteristics of thermoelectric modules as the initial data and makes it possible to determine the temperature regime and the optimal values of the feed current for the modules taking into account the thermal resistance of the heat-spreading system.

Optoelectrical Cooling of Formaldehyde to Sub-Millikelvin Temperatures

NASA Astrophysics Data System (ADS)

Zeppenfeld, Martin

2016-05-01

Due to their strong long-range dipole-dipole interactions and large number of internal states, polar molecules cooled to ultracold temperatures enable fascinating applications ranging from ultracold chemistry to investigation of dipolar quantum gases. However, realizing a simple and general technique to cool molecules to ultracold temperatures, akin to laser cooling of atoms, has been a formidable challenge. We present results for opto-electrical Sisyphus cooling applied to formaldehyde (H2 CO). In this generally applicable cooling scheme, molecules repeatedly move up and down electric field gradients of a trapping potential in different rotational states to efficiently extract kinetic energy. A total of about 300,000 molecules are thereby cooled by a factor of 1000 to 400uK, resulting in a record-large ensemble of ultracold molecules. In addition to cooling of the motional degrees of freedom, optical pumping via a vibrational transition allows us to control the internal rotational state. We thereby achieve a purity of over 80% of formaldehyde molecules in a single rotational M-sublevel. Our experiment provides an excellent starting point for precision spectroscopy and investigation of ultracold collisions.

Influence of the ambient temperature on the cooling efficiency of the high performance cooling device with thermosiphon effect

NASA Astrophysics Data System (ADS)

Nemec, Patrik; Malcho, Milan

2018-06-01

This work deal with experimental measurement and calculation cooling efficiency of the cooling device working with a heat pipe technology. The referred device in the article is cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description, working principle and construction of cooling device. The main factor affected the dissipation of high heat flux from electronic elements through the cooling device to the surrounding is condenser construction, its capacity and option of heat removal. Experimental part describe the measuring method cooling efficiency of the cooling device depending on ambient temperature in range -20 to 40°C and at heat load of electronic components 750 W. Measured results are compared with results calculation based on physical phenomena of boiling, condensation and natural convection heat transfer.

Solar heating and cooling: Technical data and systems analysis

NASA Technical Reports Server (NTRS)

Christensen, D. L.

1975-01-01

The solar energy research is reported including climatic data, architectural data, heating and cooling equipment, thermal loads, and economic data. Lists of data sources presented include: selected data sources for solar energy heating and cooling; bibliography of solar energy, and other energy sources; sources for manufacturing and sales, solar energy collectors; and solar energy heating and cooling projects.

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.

Study of thermosiphon cooling scheme for the production solenoid of the Mu2e experiment at Fermilab

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

Dhanaraj, N.; Kashikhin, V.; Peterson, T.

2014-01-29

A thermosiphon cooling scheme is envisioned for the Production Solenoid of the Mu2e experiment at Fermi National Accelerator Laboratory. The thermosiphon cooling is achieved by indirect cooling with helium at 4.7 K. The siphon tubes are welded to the solenoid outer structure. The anticipated heat loads in the solenoid is presented as well as the cooling scheme design. A thermal model using ANSYS to simulate the temperature gradient is presented. The thermal analysis also makes provisions for including the heat load generated in the coils and structures by the secondary radiation simulated using the MARS 15 code. The impact ofmore » the heat loads from supports on the solenoid cooling is studied. The thermosiphon cooling scheme is also validated using pertinent correlations to study flow reversals and the cooling regime.« less

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

Optimation of cooled shields in insulations

NASA Technical Reports Server (NTRS)

Chato, J. C.; Khodadadi, J. M.; Seyed-Yagoobi, J.

1984-01-01

A method to optimize the location, temperature, and heat dissipation rate of each cooled shield inside an insulation layer was developed. The method is based on the minimization of the entropy production rate which is proportional to the heat leak across the insulation. It is shown that the maximum number of shields to be used in most practical applications is three. However, cooled shields are useful only at low values of the overall, cold wall to hot wall absolute temperature ratio. The performance of the insulation system is relatively insensitive to deviations from the optimum values of the temperature and location of the cooling shields. Design curves for rapid estimates of the locations and temperatures of cooling shields in various types of insulations, and an equation for calculating the cooling loads for the shields are presented.

Cooling the dark energy camera instrument

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

Schmitt, R.L.; Cease, H.; /Fermilab

2008-06-01

DECam, camera for the Dark Energy Survey (DES), is undergoing general design and component testing. For an overview see DePoy, et al in these proceedings. For a description of the imager, see Cease, et al in these proceedings. The CCD instrument will be mounted at the prime focus of the CTIO Blanco 4m telescope. The instrument temperature will be 173K with a heat load of 113W. In similar applications, cooling CCD instruments at the prime focus has been accomplished by three general methods. Liquid nitrogen reservoirs have been constructed to operate in any orientation, pulse tube cryocoolers have been usedmore » when tilt angles are limited and Joule-Thompson or Stirling cryocoolers have been used with smaller heat loads. Gifford-MacMahon cooling has been used at the Cassegrain but not at the prime focus. For DES, the combined requirements of high heat load, temperature stability, low vibration, operation in any orientation, liquid nitrogen cost and limited space available led to the design of a pumped, closed loop, circulating nitrogen system. At zenith the instrument will be twelve meters above the pump/cryocooler station. This cooling system expected to have a 10,000 hour maintenance interval. This paper will describe the engineering basis including the thermal model, unbalanced forces, cooldown time, the single and two-phase flow model.« less

Mouse Embryo Cryopreservation by Rapid Cooling.

PubMed

Shaw, Jillian

2018-05-01

Embryo cryopreservation has been used to archive mouse strains. Protocols have evolved over this time and now vary considerably in terms of cryoprotectant solution, cooling and warming rates, methods to add and remove cryoprotectant, container or carrier type, volume of cryoprotectant, the stage of preimplantation development, and the use of additional treatments such as blastocyst puncture and microinjection. The rapid cooling methods use concentrated solutions of cryoprotectants to reduce the water content of the cell before cooling commences, thus preventing the formation of ice crystals. Embryos are equilibrated with the cryoprotectants, loaded into a carrier, and then rapidly cooled (e.g., by being plunged directly into LN 2 or onto a surface cooled in LN 2 ). The rapid cooling methods eliminate the need for controlled-rate freezers and seeding procedures. However, they are much more sensitive to minor variations when performing the steps. The rapid-cooling protocol described here is suitable for use with plastic insemination straws. Because it uses relatively large volumes, it is less technically demanding than some other methods that use minivolume devices. © 2018 Cold Spring Harbor Laboratory Press.

Debris trap in a turbine cooling system

DOEpatents

Wilson, Ian David

2002-01-01

In a turbine having a rotor and a plurality of stages, each stage comprising a row of buckets mounted on the rotor for rotation therewith; and wherein the buckets of at least one of the stages are cooled by steam, the improvement comprising at least one axially extending cooling steam supply conduit communicating with an at least partially annular steam supply manifold; one or more axially extending cooling steam feed tubes connected to the manifold at a location radially outwardly of the cooling steam supply conduit, the feed tubes arranged to supply cooling steam to the buckets of at least one of the plurality of stages; the manifold extending radially beyond the feed tubes to thereby create a debris trap region for collecting debris under centrifugal loading caused by rotation of the rotor.

Evaporative Cooling in a Holographic Atom Trap

NASA Technical Reports Server (NTRS)

Newell, Raymond

2003-01-01

We present progress on evaporative cooling of Rb-87 atoms in our Holographic Atom Trap (HAT). The HAT is formed by the interference of five intersecting YAG laser beams: atoms are loaded from a vapor-cell MOT into the bright fringes of the interference pattern through the dipole force. The interference pattern is composed of Talbot fringes along the direction of propagation of the YAG beams, prior to evaporative cooling each Talbot fringe contains 300,000 atoms at 50 micro-K and peak densities of 2 x 10(exp 14)/cu cm. Evaporative cooling is achieved through adiabatically decreasing the intensity of the YAG laser. We present data and calculations covering a range of HAT geometries and cooling procedures.

Optimization of cooling strategy and seeding by FBRM analysis of batch crystallization

NASA Astrophysics Data System (ADS)

Zhang, Dejiang; Liu, Lande; Xu, Shijie; Du, Shichao; Dong, Weibing; Gong, Junbo

2018-03-01

A method is presented for optimizing the cooling strategy and seed loading simultaneously. Focused beam reflectance measurement (FBRM) was used to determine the approximating optimal cooling profile. Using these results in conjunction with constant growth rate assumption, modified Mullin-Nyvlt trajectory could be calculated. This trajectory could suppress secondary nucleation and has the potential to control product's polymorph distribution. Comparing with linear and two step cooling, modified Mullin-Nyvlt trajectory have a larger size distribution and a better morphology. Based on the calculating results, the optimized seed loading policy was also developed. This policy could be useful for guiding the batch crystallization process.

Influence of the cooling degree upon performances of internal combustion engine

NASA Astrophysics Data System (ADS)

Grǎdinariu, Andrei Cristian; Mihai, Ioan

2016-12-01

Up to present, air cooling systems still raise several unsolved problems due to conditions imposed by the environment in terms of temperature and pollution levels. The present paper investigates the impact of the engine cooling degree upon its performances, as important specific power is desired for as low as possible fuel consumption. A technical solution advanced by the authors[1], consists of constructing a bi-flux compressor, which can enhance the engine's performances. The bi-flux axial compressor accomplishes two major functions, that is it cools down the engine and it also turbocharges it. The present paper investigates the temperature changes corresponding to the fresh load, during the use of a bi-flux axial compressor. This compressor is economically simple, compact, and offers an optimal response at low rotational speeds of the engine, when two compression steps are used. The influence of the relative coefficient of air temperature drop upon working agent temperature at the intercooler exit is also investigated in the present work. The variation of the thermal load coefficient by report to the working agent temperature is also investigated during engine cooling. The variation of the average combustion temperature is analyzed in correlation to the thermal load coefficient and the temperatures of the working fluid at its exit from the cooling system. An exergetic analysis was conducted upon the influence of the cooling degree on the motor fluid and the gases resulted from the combustion process.

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.

The integration of liquid cryogen cooling and cryocoolers withsuperconducting electronic systems

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

Green, Michael A.

2003-07-09

The need for cryogenic cooling has been a critical issuethat has kept superconducting electronic devices from reaching the marketplace. Even though the performance of many of the superconductingcircuits is superior to silicon electronics, the requirement forcryogenic cooling has put the superconducting devices at a seriousdisadvantage. This report discusses the process of refrigeratingsuperconducting devices with cryogenic liquids and small cryocoolers.Three types of cryocoolers are compared for vibration, efficiency, andreliability. The connection of a cryocooler to the load is discussed. Acomparison of using flexible copper straps to carry the heat load andusing heat pipe is shown. The type of instrumentation needed formonitoringmore » and controlling the cooling is discussed.« less

Heat dissipation in water-cooled reflectors

NASA Technical Reports Server (NTRS)

Kozai, Toyoki

1994-01-01

The energy balance of a lamp varies with the thermal and optical characteristics of the reflector. The photosynthetic radiation efficiency of lamps, defined as input power divided by photosynthetically active radiation (PAR, 400-700 nm) emitted from the lamp ranges between 0.17 and 0.26. The rest of the energy input is wasted as longwave (3000 nm and over) and non-PAR shortwave radiation (from 700 nm to 3000 nm), convective, and conductive heat from the lamp, reflector, and ballast, and simply for increasing the cooling load. Furthermore, some portion of the PAR is uselessly absorbed by the inner walls, shelves, vessels, etc. and some portion of the PAR received by the plantlets is converted into sensible and latent heat. More than 98% of the energy input is probably converted into heat, with only less than 2% of the energy input being converted into chemical energy as carbohydrates by photosynthesis. Therefore, it is essential to reduce the generation of heat in the culture room in order to reduce the cooling load. Through use of a water-cooled reflector, the generation of convective and conductive heat and longwave radiation from the reflector can be reduced, without reduction of PAR.

Daily Air Temperature and Electricity Load in Spain.

NASA Astrophysics Data System (ADS)

Valor, Enric; Meneu, Vicente; Caselles, Vicente

2001-08-01

Weather has a significant impact on different sectors of the economy. One of the most sensitive is the electricity market, because power demand is linked to several weather variables, mainly the air temperature. This work analyzes the relationship between electricity load and daily air temperature in Spain, using a population-weighted temperature index. The electricity demand shows a significant trend due to socioeconomic factors, in addition to daily and monthly seasonal effects that have been taken into account to isolate the weather influence on electricity load. The results indicate that the relationship is nonlinear, showing a `comfort interval' of ±3°C around 18°C and two saturation points beyond which the electricity load no longer increases. The analysis has also revealed that the sensitivity of electricity load to daily air temperature has increased along time, in a higher degree for summer than for winter, although the sensitivity in the cold season is always more significant than in the warm season. Two different temperature-derived variables that allow a better characterization of the observed relationship have been used: the heating and cooling degree-days. The regression of electricity data on them defines the heating and cooling demand functions, which show correlation coefficients of 0.79 and 0.87, and predicts electricity load with standard errors of estimate of ±4% and ±2%, respectively. The maximum elasticity of electricity demand is observed at 7 cooling degree-days and 9 heating degree-days, and the saturation points are reached at 11 cooling degree-days and 13 heating degree-days, respectively. These results are helpful in modeling electricity load behavior for predictive purposes.

Contrastive analysis of cooling performance between a high-level water collecting cooling tower and a typical cooling tower

NASA Astrophysics Data System (ADS)

Wang, Miao; Wang, Jin; Wang, Jiajin; Shi, Cheng

2018-02-01

A three-dimensional (3D) numerical model is established and validated for cooling performance optimization between a high-level water collecting natural draft wet cooling tower (HNDWCT) and a usual natural draft wet cooling tower (UNDWCT) under the actual operation condition at Wanzhou power plant, Chongqing, China. User defined functions (UDFs) of source terms are composed and loaded into the spray, fill and rain zones. Considering the conditions of impact on three kinds of corrugated fills (Double-oblique wave, Two-way wave and S wave) and four kinds of fill height (1.25 m, 1.5 m, 1.75 m and 2 m), numerical simulation of cooling performance are analysed. The results demonstrate that the S wave has the highest cooling efficiency in three fills for both towers, indicating that fill characteristics are crucial to cooling performance. Moreover, the cooling performance of the HNDWCT is far superior to that of the UNDWCT with fill height increases of 1.75 m and above, because the air mass flow rate in the fill zone of the HNDWCT improves more than that in the UNDWCT, as a result of the rain zone resistance declining sharply for the HNDWCT. In addition, the mass and heat transfer capacity of the HNDWCT is better in the tower centre zone than in the outer zone near the tower wall under a uniform fill layout. This behaviour is inverted for the UNDWCT, perhaps because the high-level collection devices play the role of flow guiding in the inner zone. Therefore, when non-uniform fill layout optimization is applied to the HNDWCT, the inner zone increases in height from 1.75 m to 2 m, the outer zone reduces in height from 1.75 m to 1.5 m, and the outlet water temperature declines approximately 0.4 K compared to that of the uniform layout.

High-Performance Computing Data Center Cooling System Energy Efficiency |

Science.gov Websites

approaches involve a cooling distribution unit (CDU) (2), which interfaces with the facility cooling loop and to the energy recovery water (ERW) loop (5), which is a closed-loop system. There are three heat rejection options for this IT load: When possible, heat energy from the energy recovery loop is transferred

Effectiveness of eugenol sedation to reduce the metabolic rates of cool and warm water fish at high loading densities

USGS Publications Warehouse

Cupp, Aaron R.; Hartleb, Christopher F.; Fredricks, Kim T.; Gaikowski, Mark P.

2016-01-01

Effects of eugenol (AQUI-S®20E, 10% active eugenol) sedation on cool water, yellow perch Perca flavescens (Mitchill), and warm water, Nile tilapia Oreochromis niloticus L. fish metabolic rates were assessed. Both species were exposed to 0, 10, 20 and 30 mg L−1 eugenol using static respirometry. In 17°C water and loading densities of 60, 120 and 240 g L−1, yellow perch controls (0 mg L−1 eugenol) had metabolic rates of 329.6–400.0 mg O2 kg−1 h−1, while yellow perch exposed to 20 and 30 mg L−1 eugenol had significantly reduced metabolic rates of 258.4–325.6 and 189.1–271.0 mg O2 kg−1 h−1 respectively. Nile tilapia exposed to 30 mg L−1 eugenol had a significantly reduced metabolic rate (424.5 ± 42.3 mg O2 kg−1 h−1) relative to the 0 mg L−1 eugenol control (546.6 ± 53.5 mg O2 kg−1 h−1) at a loading density of 120 g L−1 in 22°C water. No significant differences in metabolic rates for Nile tilapia were found at 240 or 360 g L−1 loading densities when exposed to eugenol. Results suggest that eugenol sedation may benefit yellow perch welfare at high densities (e.g. live transport) due to a reduction in metabolic rates, while further research is needed to assess the benefits of eugenol sedation on Nile tilapia at high loading densities.

Glycaemic index and glycaemic load values of cereal products and weight-management meals available in the UK.

PubMed

Henry, C Jeya K; Lightowler, Helen J; Dodwell, Lis M; Wynne, Jacqueline M

2007-07-01

There is currently an increased global interest in the published glycaemic index (GI) values of foods. The aim of the present work was to supplement a previous study on the glycaemic response of 140 foods available in the UK by studying a further forty-four foods. One hundred and twenty-two healthy subjects, with a mean age of 32.4 (sd 11.4) years and a mean BMI of 23.6 (sd 3.6) kg/m2, were recruited to the study. Subjects were served equivalent available carbohydrate amounts (50 or 30 g) of test foods (cereal products and weight-management meals) and a standard food (glucose) on separate occasions. Capillary blood glucose was measured from finger-prick samples in fasted subjects (0 min) and at 15, 30, 45, 60, 90 and 120 min after starting to eat each test food. For each test food, the GI value was determined, and the glycaemic load was calculated as the product of the GI and the amount of available carbohydrate in a reference serving size. The GI values of the foods tested ranged from 23 to 83. Of the forty-four foods tested, thirty-three were classified as low-GI, eight as medium-GI and three as high-GI foods. Most GI values of the foods tested compared well with previously published values for similar foods. In summary, this study provides reliable GI and glycaemic load values for a range of foods, further advancing our understanding of the glycaemic response of different foods. The data reported here make an important addition to published GI values.

AIR COOLED NEUTRONIC REACTOR

DOEpatents

Fermi, E.; Szilard, L.

1958-05-27

A nuclear reactor of the air-cooled, graphite moderated type is described. The active core consists of a cubicle mass of graphite, approximately 25 feet in each dimension, having horizontal channels of square cross section extending between two of the opposite faces, a plurality of cylindrical uranium slugs disposed in end to end abutting relationship within said channels providing a space in the channels through which air may be circulated, and a cadmium control rod extending within a channel provided in the moderator. Suitable shielding is provlded around the core, as are also provided a fuel element loading and discharge means, and a means to circulate air through the coolant channels through the fuel charels to cool the reactor.

Thermal performance of phase change wallboard for residential cooling application

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

Feustel, H.E.; Stetiu, C.

1997-04-01

Cooling of residential California buildings contributes significantly to electrical consumption and peak power demand mainly due to very poor load factors in milder climates. Thermal mass can be utilized to reduce the peak-power demand, downsize the cooling systems, and/or switch to low-energy cooling sources. Large thermal storage devices have been used in the past to overcome the shortcomings of alternative cooling sources, or to avoid high demand charges. The manufacturing of phase change material (PCM) implemented in gypsum board, plaster or other wall-covering material, would permit the thermal storage to become part of the building structure. PCMs have two importantmore » advantages as storage media: they can offer an order-of-magnitude increase in thermal storage capacity, and their discharge is almost isothermal. This allows the storage of high amounts of energy without significantly changing the temperature of the room envelope. As heat storage takes place inside the building, where the loads occur, rather than externally, additional transport energy is not required. RADCOOL, a thermal building simulation program based on the finite difference approach, was used to numerically evaluate the latent storage performance of treated wallboard. Extended storage capacity obtained by using double PCM-wallboard is able to keep the room temperatures close to the upper comfort limits without using mechanical cooling. Simulation results for a living room with high internal loads and weather data for Sunnyvale, California, show significant reduction of room air temperature when heat can be stored in PCM-treated wallboards.« less

The updated algorithm of the Energy Consumption Program (ECP): A computer model simulating heating and cooling energy loads in buildings

NASA Technical Reports Server (NTRS)

Lansing, F. L.; Strain, D. M.; Chai, V. W.; Higgins, S.

1979-01-01

The energy Comsumption Computer Program was developed to simulate building heating and cooling loads and compute thermal and electric energy consumption and cost. This article reports on the new additional algorithms and modifications made in an effort to widen the areas of application. The program structure was rewritten accordingly to refine and advance the building model and to further reduce the processing time and cost. The program is noted for its very low cost and ease of use compared to other available codes. The accuracy of computations is not sacrificed however, since the results are expected to lie within + or - 10% of actual energy meter readings.

Evaluation by Rocket Combustor of C/C Composite Cooled Structure Using Metallic Cooling Tubes

NASA Astrophysics Data System (ADS)

Takegoshi, Masao; Ono, Fumiei; Ueda, Shuichi; Saito, Toshihito; Hayasaka, Osamu

In this study, the cooling performance of a C/C composite material structure with metallic cooling tubes fixed by elastic force without chemical bonding was evaluated experimentally using combustion gas in a rocket combustor. The C/C composite chamber was covered by a stainless steel outer shell to maintain its airtightness. Gaseous hydrogen as a fuel and gaseous oxygen as an oxidizer were used for the heating test. The surface of these C/C composites was maintained below 1500 K when the combustion gas temperature was about 2800 K and the heat flux to the combustion chamber wall was about 9 MW/m2. No thermal damage was observed on the stainless steel tubes that were in contact with the C/C composite materials. The results of the heating test showed that such a metallic tube-cooled C/C composite structure is able to control the surface temperature as a cooling structure (also as a heat exchanger) as well as indicated the possibility of reducing the amount of coolant even if the thermal load to the engine is high. Thus, application of this metallic tube-cooled C/C composite structure to reusable engines such as a rocket-ramjet combined-cycle engine is expected.

Analysis and comparison of wall cooling schemes for advanced gas turbine applications

NASA Technical Reports Server (NTRS)

Colladay, R. S.

1972-01-01

The relative performance of (1) counterflow film cooling, (2) parallel-flow film cooling, (3) convection cooling, (4) adiabatic film cooling, (5) transpiration cooling, and (6) full-coverage film cooling was investigated for heat loading conditions expected in future gas turbine engines. Assumed in the analysis were hot-gas conditions of 2200 K (3500 F) recovery temperature, 5 to 40 atmospheres total pressure, and 0.6 gas Mach number and a cooling air supply temperature of 811 K (1000 F). The first three cooling methods involve film cooling from slots. Counterflow and parallel flow describe the direction of convection cooling air along the inside surface of the wall relative to the main gas flow direction. The importance of utilizing the heat sink available in the coolant for convection cooling prior to film injection is illustrated.

Investigating the use of paired Uk'37 and TEX86 measurements to reconstruct past sea surface and subsurface (thermocline) temperatures (Invited)

NASA Astrophysics Data System (ADS)

Castaneda, I. S.; Urann, B.; Phu, V.

2013-12-01

Two organic geochemical temperature proxies widely applied to marine sediments are the Uk'37 Index, based on long-chain alkenones produced by haptophyte algae, and TEX86, based on isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs), produced by Thaumarchaeota. At some locations, temperature reconstructions based on Uk'37 and TEX86 are in agreement within the calibration errors of each proxy, while at other sites absolute Uk'37 and TEX86 reconstructed temperatures differ but both proxies reveal similar overall trends (e.g. Caley et al., 2011). In contrast, at other locations Uk'37 and TEX86 temperature reconstructions from the same samples yield dramatically different overall trends. Differences observed between Uk'37 and TEX86 temperature reconstructions have been attributed to a variety of factors including seasonal production biases, differences in preservation and lateral transport, and differences related to the depth habitat of the source organisms. An increasing number of studies have provided evidence that TEX86 likely reflects a subsurface water temperature in certain areas of the world's oceans and have used paired Uk'37 and TEX86 measurements to simultaneously examine sea surface and subsurface (in some cases thermocline) temperature variability (e.g. Lopes dos Santos et al., 2010; Rommerskirchen et al., 2011; Li et al., 2013). In the tropical N Atlantic, a distinctive signature of Atlantic Meridional Overturning Circulation (AMOC) slowdown is anticorrelated variation between surface and subsurface water temperatures (e.g. Chang et al., 2008; Zhang et al., 2007) where sea surface temperature (SST) cooling is accompanied by shallow subsurface warming (e.g. Chang et al., 2008). Lopes dos Santos et al. (2010) examined a site in the tropical NE Atlantic where they showed that in the modern Uk'37 reflects SST while TEXH86 likely reflects a thermocline temperature. The authors noted several periods during the past 200 kyr when surface cooling and

Passive Cooling of Body Armor

NASA Astrophysics Data System (ADS)

Holtz, Ronald; Matic, Peter; Mott, David

2013-03-01

Warfighter performance can be adversely affected by heat load and weight of equipment. Current tactical vest designs are good insulators and lack ventilation, thus do not provide effective management of metabolic heat generated. NRL has undertaken a systematic study of tactical vest thermal management, leading to physics-based strategies that provide improved cooling without undesirable consequences such as added weight, added electrical power requirements, or compromised protection. The approach is based on evaporative cooling of sweat produced by the wearer of the vest, in an air flow provided by ambient wind or ambulatory motion of the wearer. Using an approach including thermodynamic analysis, computational fluid dynamics modeling, air flow measurements of model ventilated vest architectures, and studies of the influence of fabric aerodynamic drag characteristics, materials and geometry were identified that optimize passive cooling of tactical vests. Specific architectural features of the vest design allow for optimal ventilation patterns, and selection of fabrics for vest construction optimize evaporation rates while reducing air flow resistance. Cooling rates consistent with the theoretical and modeling predictions were verified experimentally for 3D mockups.

Cooling atomic ions with visible and infra-red light

NASA Astrophysics Data System (ADS)

Lindenfelser, F.; Marinelli, M.; Negnevitsky, V.; Ragg, S.; Home, J. P.

2017-06-01

We demonstrate the ability to load, cool and detect singly charged calcium ions in a surface electrode trap using only visible and infrared lasers for the trapped-ion control. As opposed to the standard methods of cooling using dipole-allowed transitions, we combine power broadening of a quadrupole transition at 729 nm with quenching of the upper level using a dipole allowed transition at 854 nm. By observing the resulting 393 nm fluorescence we are able to perform background-free detection of the ion. We show that this system can be used to smoothly transition between the Doppler cooling and sideband cooling regimes, and verify theoretical predictions throughout this range. We achieve scattering rates which reliably allow recooling after collision events and allow ions to be loaded from a thermal atomic beam. This work is compatible with recent advances in optical waveguides, and thus opens a path in current technologies for large-scale quantum information processing. In situations where dielectric materials are placed close to trapped ions, it carries the additional advantage of using wavelengths which do not lead to significant charging, which should facilitate high rate optical interfaces between remotely held ions.

Radiative, actively cooled panel tests results

NASA Technical Reports Server (NTRS)

Shore, C. P.; Nowak, R. J.; Sharpe, E. L.

1978-01-01

The radiative, actively cooled panel designed to withstand a uniform incident heat flux of 136 kW/sq m to a 444 K surface temperature was evaluated. The test program consisted of preliminary static thermal mechanical loading and aerothermal flow tests. Test results are briefly discussed.

Climate Control Load Reduction Strategies for Electric Drive Vehicles in Warm Weather

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

Jeffers, M. A.; Chaney, L.; Rugh, J. P.

Passenger compartment climate control is one of the largest auxiliary loads on a vehicle. Like conventional vehicles, electric vehicles (EVs) require climate control to maintain occupant comfort and safety, but cabin heating and air conditioning have a negative impact on driving range for all electric vehicles. Range reduction caused by climate control and other factors is a barrier to widespread adoption of EVs. Reducing the thermal loads on the climate control system will extend driving range, thereby reducing consumer range anxiety and increasing the market penetration of EVs. Researchers at the National Renewable Energy Laboratory have investigated strategies for vehiclemore » climate control load reduction, with special attention toward EVs. Outdoor vehicle thermal testing was conducted on two 2012 Ford Focus Electric vehicles to evaluate thermal management strategies for warm weather, including solar load reduction and cabin pre-ventilation. An advanced thermal test manikin was used to assess a zonal approach to climate control. In addition, vehicle thermal analysis was used to support testing by exploring thermal load reduction strategies, evaluating occupant thermal comfort, and calculating EV range impacts. Through stationary cooling tests and vehicle simulations, a zonal cooling configuration demonstrated range improvement of 6%-15%, depending on the drive cycle. A combined cooling configuration that incorporated thermal load reduction and zonal cooling strategies showed up to 33% improvement in EV range.« less

46 CFR 154.411 - Cargo tank thermal loads.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Cargo tank thermal loads. 154.411 Section 154.411... Containment Systems § 154.411 Cargo tank thermal loads. For the calculations required under § 154.406(a)(4... thermal loads for the cooling down periods of cargo tanks for design temperatures lower than −55 °C (−67...

46 CFR 154.411 - Cargo tank thermal loads.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo tank thermal loads. 154.411 Section 154.411... Containment Systems § 154.411 Cargo tank thermal loads. For the calculations required under § 154.406(a)(4... thermal loads for the cooling down periods of cargo tanks for design temperatures lower than −55 °C (−67...

Cooling devices and methods for use with electric submersible pumps

DOEpatents

Jankowski, Todd A; Hill, Dallas D

2014-12-02

Cooling devices for use with electric submersible pump motors include a refrigerator attached to the end of the electric submersible pump motor with the evaporator heat exchanger accepting all or a portion of the heat load from the motor. The cooling device can be a self-contained bolt-on unit, so that minimal design changes to existing motors are required.

Cooling devices and methods for use with electric submersible pumps

DOEpatents

Jankowski, Todd A.; Hill, Dallas D.

2016-07-19

Cooling devices for use with electric submersible pump motors include a refrigerator attached to the end of the electric submersible pump motor with the evaporator heat exchanger accepting all or a portion of the heat load from the motor. The cooling device can be a self-contained bolt-on unit, so that minimal design changes to existing motors are required.

Constructed wetlands in UK urban surface drainage systems.

PubMed

Shutes, B; Ellis, J B; Revitt, D M; Scholes, L N L

2005-01-01

This paper presents the outcome of an inventory of planted wetland systems in the UK which are classified according to land use type and are all examples of sustainable drainage systems. The introduction of constructed wetlands to treat surface runoff essentially followed a 1997 Environment Agency for England and Wales report advocating the use of "soft engineered" facilities including wetlands in the context of sustainable development and Agenda 21. Subsequently published reports by the UK Construction Industry Research and Information Association (CIRIA) have promoted the potential benefits to both developer and the community of adopting constructed wetlands and other vegetated systems as a sustainable drainage approach. In addition, the UK Environment Agency and Highways Agency (HA) have recently published their own design criteria and requirements for vegetative control and treatment of road runoff. A case study of the design and performance of a constructed wetland system for the treatment of road runoff is discussed. The performance of these systems will be assessed in terms of their design criteria, runoff loadings as well as vegetation and structure maintenance procedures. The differing design approaches in guidance documents published in the UK by the Environment Agency, CIRIA and HA will also be evaluated.

Estimating the CO2 mitigation potential of horizontal Ground Source Heat Pumps in the UK

NASA Astrophysics Data System (ADS)

Garcia-Gonzalez, R.; Verhoef, A.; Vidale, P. L.; Gan, G.; Chong, A.; Clark, D.

2012-04-01

By 2020, the UK will need to generate 15% of its energy from renewables to meet our contribution to the EU renewable energy target. Heating and cooling systems of buildings account for 30%-50% of the global energy consumption; thus, alternative low-carbon technologies such as horizontal Ground Couple Heat Pumps (GCHPs) can contribute to the reduction of anthropogenic CO2 emissions. Horizontal GCHPs currently represent a small fraction of the total energy generation in the UK. However, the fact that semi-detached and detached dwellings represent approximately 40% of the total housing stocks in the UK could make the widespread implementation of this technology particularly attractive in the UK and so could significantly increase its renewable energy generation potential. Using a simulation model, we analysed the dynamic interactions between the environment, the horizontal GCHP heat exchanger and typical UK dwellings, as well as their combined effect on heat pump performance and CO2 mitigation potential. For this purpose, a land surface model (JULES, Joint UK Land Environment Simulator), which calculates coupled soil heat and water fluxes, was combined with a heat extraction model. The analyses took into account the spatio-temporal variability of soil properties (thermal and hydraulic) and meteorological variables, as well as different horizontal GCHP configurations and a variety of building loads and heat demands. Sensitivity tests were performed for four sites in the UK with different climate and soil properties. Our results show that an installation depth of 1.0m would give us higher heat extractions rates, however it would be preferable to install the pipes slightly deeper to avoid the seasonal influence of variable meteorological conditions. A value of 1.5m for the spacing between coils (S) for a slinky configuration type is recommended to avoid thermal disturbances between neighbouring coils. We also found that for larger values of the spacing between the coils

Study of active cooling for supersonic transports

NASA Technical Reports Server (NTRS)

Brewer, G. D.; Morris, R. E.

1975-01-01

The potential benefits of using the fuel heat sink of hydrogen fueled supersonic transports for cooling large portions of the aircraft wing and fuselage are examined. The heat transfer would be accomplished by using an intermediate fluid such as an ethylene glycol-water solution. Some of the advantages of the system are: (1) reduced costs by using aluminum in place of titanium, (2) reduced cabin heat loads, and (3) more favorable environmental conditions for the aircraft systems. A liquid hydrogen fueled, Mach 2.7 supersonic transport aircraft design was used for the reference uncooled vehicle. The cooled aircraft designs were analyzed to determine their heat sink capability, the extent and location of feasible cooled surfaces, and the coolant passage size and spacing.

Evaporative cooling of the dipolar hydroxyl radical.

PubMed

Stuhl, Benjamin K; Hummon, Matthew T; Yeo, Mark; Quéméner, Goulven; Bohn, John L; Ye, Jun

2012-12-20

Atomic physics was revolutionized by the development of forced evaporative cooling, which led directly to the observation of Bose-Einstein condensation, quantum-degenerate Fermi gases and ultracold optical lattice simulations of condensed-matter phenomena. More recently, substantial progress has been made in the production of cold molecular gases. Their permanent electric dipole moment is expected to generate systems with varied and controllable phases, dynamics and chemistry. However, although advances have been made in both direct cooling and cold-association techniques, evaporative cooling has not been achieved so far. This is due to unfavourable ratios of elastic to inelastic scattering and impractically slow thermalization rates in the available trapped species. Here we report the observation of microwave-forced evaporative cooling of neutral hydroxyl (OH(•)) molecules loaded from a Stark-decelerated beam into an extremely high-gradient magnetic quadrupole trap. We demonstrate cooling by at least one order of magnitude in temperature, and a corresponding increase in phase-space density by three orders of magnitude, limited only by the low-temperature sensitivity of our spectroscopic thermometry technique. With evaporative cooling and a sufficiently large initial population, much colder temperatures are possible; even a quantum-degenerate gas of this dipolar radical (or anything else it can sympathetically cool) may be within reach.

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

Thermal Design of Vapor Cooling of Flight Vehicle Structures Using LH2 Boil-Off

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen; Zoeckler, Joseph

2015-01-01

Using hydrogen boil-off vapor to cool the structure of a flight vehicle cryogenic upper stage can reduce heat loads to the stage and increase the usable propellant in the stage or extend the life of the stage. The hydrogen vapor can be used to absorb incoming heat as it increases in temperature before being vented overboard. In theory, the amount of heat leaking into the hydrogen tank from the structure will be reduced if the structure is cooled using the propellant boil-off vapor. However, the amount of boil-off vapor available to be used for cooling and the reduction in heat leak to the propellant tank are dependent to each other. The amount of heat leak reduction to the LH2 tank also depends on the total heat load on the stage and the vapor cooling configurations.

Fail-safe system for activity cooled supersonic and hypersonic aircraft. [using liquid hydrogen fuel

NASA Technical Reports Server (NTRS)

Jones, R. A.; Braswell, D. O.; Richie, C. B.

1975-01-01

A fail-safe-system concept was studied as an alternative to a redundant active cooling system for supersonic and hypersonic aircraft which use the heat sink of liquid-hydrogen fuel for cooling the aircraft structure. This concept consists of an abort maneuver by the aircraft and a passive thermal protection system (TPS) for the aircraft skin. The abort manuever provides a low-heat-load descent from normal cruise speed to a lower speed at which cooling is unnecessary, and the passive TPS allows the aircraft skin to absorb the abort heat load without exceeding critical skin temperature. On the basis of results obtained, it appears that this fail-safe-system concept warrants further consideration, inasmuch as a fail-safe system could possibly replace a redundant active cooling system with no increase in weight and would offer other potential advantages.

Plasma Wind Tunnel Testing of Electron Transpiration Cooling Concept

DTIC Science & Technology

2017-02-28

AFRL-AFOSR-UK-TR-2017-0012 Plasma Wind Tunnel Testing of Electron Transpiration Cooling Concept Olivier Chazot INSTITUT VON KARMAN DE DYNAMIQUE DES...28-02-2017 2. REPORT TYPE Final 3. DATES COVERED (From - To) 01 Dec 2015 to 30 Nov 2016 4. TITLE AND SUBTITLE Plasma Wind Tunnel Testing of Electron ...Aeronautics and Aerospace Department B-1640 Rhode Saint Genèse Belgium Internal Ref: ARR 1605 February 2017 Plasma Wind Tunnel Testing of Electron

Flexible Residential Test Facility: Impact of Infiltration and Ventilation on Measured Cooling Season Energy and Moisture Levels

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

Parker, Danny S.; Cummings, Jamie E.; Vieira, Robin K.

Air infiltration and ventilation in residential buildings is a very large part of the heating loads, but empirical data regarding the impact on space cooling has been lacking. Moreover, there has been little data on how building tightness might relate to building interior moisture levels in homes in a hot and humid climate. To address this need, BA-PIRC has conducted research to assess the moisture and cooling load impacts of airtightness and mechanical ventilation in two identical laboratory homes in the hot-humid climate over the cooling season.

Re-employment, job quality, health and allostatic load biomarkers: prospective evidence from the UK Household Longitudinal Study

PubMed Central

Chandola, Tarani; Zhang, Nan

2018-01-01

Abstract Background There is little evidence on whether becoming re-employed in poor quality work is better for health and well-being than remaining unemployed. We examined associations of job transition with health and chronic stress-related biomarkers among a population-representative cohort of unemployed British adults. Methods A prospective cohort of 1116 eligible participants aged 35 to 75 years, who were unemployed at wave 1 (2009/10) of the UK Household Longitudinal Study, were followed up at waves 2 (2010/11) and 3 (2011/12) for allostatic load biomarkers and self-reported health. Negative binomial and multiple regression models estimated the association between job adversity and these outcomes. Results Compared with adults who remained unemployed, formerly unemployed adults who transitioned into poor quality jobs had higher levels of overall allostatic load (0.51, 0.32–0.71), log HbA1c (0.06, <0.001–0.12), log triglycerides (0.39, 0.22–0.56), log C-reactive protein (0.45, 0.16–0.75), log fibrinogen (0.09, 0.01–0.17) and total cholesterol to high-density lipoprotein (HDL) ratio (1.38, 0.88–1.88). Moreover, physically healthier respondents at wave 1 were more likely to transition into good quality and poor quality jobs after 1 year than those who remained unemployed. Conclusions Formerly unemployed adults who transitioned into poor quality work had greater adverse levels of biomarkers compared with their peers who remained unemployed. The selection of healthier unemployed adults into these poor quality or stressful jobs was unlikely to explain their elevated levels of chronic stress-related biomarkers. Job quality cannot be disregarded from the employment success of the unemployed, and may have important implications for their health and well-being. PMID:29024973

Macrophyte Community Response to Nitrogen Loading and ...

EPA Pesticide Factsheets

Empirical determination of nutrient loading thresholds that negatively impact seagrass communities have been elusive due to the multitude of factors involved. Using a mesocosm system that simulated Pacific Northwest estuaries, we evaluated macrophyte metrics across gradients of NO3 loading (0, 1.5, 3 and 6x ambient) and temperature (10 and 20 °C). Macroalgal growth, biomass, and C:N responded positively to increased NO3 load and floating algal mats developed at 20 ºC. Zostera japonica metrics, including C:N, responded more to temperature than to NO3 loading. Z. marina biomass exhibited a negative temperature effect and in some cases a negative NO3 effect, while growth rate increased with temperature. Shoot survival decreased at 20 ºC but was not influenced by NO3 loading. Wasting disease index exhibited a significant temperature by NO3 interaction consistent with increased disease susceptibility. Community shifts observed were consistent with the nutrient loading hypothesis at 20 ºC, but there was no evidence of other eutrophication symptoms due to the short residence time. The Nutrient Pollution Index tracked the NO3 gradient at 10 ºC but exhibited no response at 20 ºC. We suggest that systems characterized by cool temperatures, high NO3 loads, and short residence time may be resilient to many symptoms of eutrophication. Estuarine systems characterized by cool temperatures, high nutrient loads and rapid flushing may be resilient to some symptoms

Comparison of simulated and experimental results of temperature distribution in a closed two-phase thermosyphon cooling system

NASA Astrophysics Data System (ADS)

Shaanika, E.; Yamaguchi, K.; Miki, M.; Ida, T.; Izumi, M.; Murase, Y.; Oryu, T.; Yanamoto, T.

2017-12-01

Superconducting generators offer numerous advantages over conventional generators of the same rating. They are lighter, smaller and more efficient. Amongst a host of methods for cooling HTS machinery, thermosyphon-based cooling systems have been employed due to their high heat transfer rate and near-isothermal operating characteristics associated with them. To use them optimally, it is essential to study thermal characteristics of these cryogenic thermosyphons. To this end, a stand-alone neon thermosyphon cooling system with a topology resembling an HTS rotating machine was studied. Heat load tests were conducted on the neon thermosyphon cooling system by applying a series of heat loads to the evaporator at different filling ratios. The temperature at selected points of evaporator, adiabatic tube and condenser as well as total heat leak were measured. A further study involving a computer thermal model was conducted to gain further insight into the estimated temperature distribution of thermosyphon components and heat leak of the cooling system. The model employed boundary conditions from data of heat load tests. This work presents a comparison between estimated (by model) and experimental (measured) temperature distribution in a two-phase cryogenic thermosyphon cooling system. The simulation results of temperature distribution and heat leak compared generally well with experimental data.

Effects of cooling rate on particle rearrangement statistics: Rapidly cooled glasses are more ductile and less reversible.

PubMed

Fan, Meng; Wang, Minglei; Zhang, Kai; Liu, Yanhui; Schroers, Jan; Shattuck, Mark D; O'Hern, Corey S

2017-02-01

Amorphous solids, such as metallic, polymeric, and colloidal glasses, display complex spatiotemporal response to applied deformations. In contrast to crystalline solids, during loading, amorphous solids exhibit a smooth crossover from elastic response to plastic flow. In this study, we investigate the mechanical response of binary Lennard-Jones glasses to athermal, quasistatic pure shear as a function of the cooling rate used to prepare them. We find several key results concerning the connection between strain-induced particle rearrangements and mechanical response. We show that the energy loss per strain dU_{loss}/dγ caused by particle rearrangements for more rapidly cooled glasses is larger than that for slowly cooled glasses. We also find that the cumulative energy loss U_{loss} can be used to predict the ductility of glasses even in the putative linear regime of stress versus strain. U_{loss} increases (and the ratio of shear to bulk moduli decreases) with increasing cooling rate, indicating enhanced ductility. In addition, we characterized the degree of reversibility of particle motion during a single shear cycle. We find that irreversible particle motion occurs even in the linear regime of stress versus strain. However, slowly cooled glasses, which undergo smaller rearrangements, are more reversible during a single shear cycle than rapidly cooled glasses. Thus, we show that more ductile glasses are also less reversible.

Solar Heating and Cooling of Buildings (Phase O). Volume 1: Executive Summary.

ERIC Educational Resources Information Center

TRW Systems Group, Redondo Beach, CA.

The purpose of this study was to establish the technical and economic feasibility of using solar energy for the heating and cooling of buildings. Five selected building types in 14 selected cities were used to determine loads for space heating, space cooling and dehumidification, and domestic service hot water heating. Relying on existing and…

Estimation of the residual bromine concentration after disinfection of cooling water by statistical evaluation.

PubMed

Megalopoulos, Fivos A; Ochsenkuehn-Petropoulou, Maria T

2015-01-01

A statistical model based on multiple linear regression is developed, to estimate the bromine residual that can be expected after the bromination of cooling water. Make-up water sampled from a power plant in the Greek territory was used for the creation of the various cooling water matrices under investigation. The amount of bromine fed to the circuit, as well as other important operational parameters such as concentration at the cooling tower, temperature, organic load and contact time are taken as the independent variables. It is found that the highest contribution to the model's predictive ability comes from cooling water's organic load concentration, followed by the amount of bromine fed to the circuit, the water's mean temperature, the duration of the bromination period and finally its conductivity. Comparison of the model results with the experimental data confirms its ability to predict residual bromine given specific bromination conditions.

Pressure Available for Cooling with Cowling Flaps

NASA Technical Reports Server (NTRS)

Stickle, George W; Naiman, Irven; Crigler, John L

1941-01-01

Report presents the results of a full-scale investigation conducted in the NACA 20-foot tunnel to determine the pressure difference available for cooling with cowling flaps. The flaps were applied to an exit slot of smooth contour at 0 degree flap angle. Flap angles of 0 degree, 15 degrees, and 30 degrees were tested. Two propellers were used; propeller c which has conventional round blade shanks and propeller f which has airfoil sections extending closer to the hub. The pressure available for cooling is shown to be a direct function of the thrust disk-loading coefficient of the propeller.

Evaluation of solar gain through skylights for inclusion in the SP53 residential building loads data base

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

Hanford, J.W.; Huang, Y.J.

The energy performance of skylights is similar to that of windows in admitting solar heat gain, while at the same time providing a pathway for convective and conductive heat transfer through the building envelope. Since skylights are typically installed at angles ranging from 0{degrees} to 45{degrees}, and differ from windows in both their construction and operation, their conductive and convective heat gains or losses, as well as solar heat gain, will differ for the same rough opening and thermal characteristics. The objective of this work is to quantify the impact of solar gain through skylights on building heating and coolingmore » loads in 45 climates, and to develop a method for including these data into the SP53 residential loads data base previously developed by LBL in support of DOE`s Automated Residential Energy Standard (ARES) program. The authors used the DOE-2.1C program to simulate the heating and cooling loads of a prototypical residential building while varying the size and solar characteristics of skylights and windows. The results are presented as Skylight Solar Loads, which are the contribution of solar gains through skylights to the overall building heating and cooling loads, and as Skylight Solar Load Ratios, which are the ratios of skylight solar loads to those for windows with the same orientation. The study shows that skylight solar loads are larger than those for windows in both heating and cooling. Skylight solar cooling loads are from three to four times greater than those for windows regardless of the skylight tilt, except for those facing north. These cooling loads are largest for south-facing skylights at a tilt angle of approximately 20{degrees}, and drop off at higher tilts and other orientations.« less

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.

Active cooling of microvascular composites for battery packaging

NASA Astrophysics Data System (ADS)

Pety, Stephen J.; Chia, Patrick X. L.; Carrington, Stephen M.; White, Scott R.

2017-10-01

Batteries in electric vehicles (EVs) require a packaging system that provides both thermal regulation and crash protection. A novel packaging scheme is presented that uses active cooling of microvascular carbon fiber reinforced composites to accomplish this multifunctional objective. Microvascular carbon fiber/epoxy composite panels were fabricated and their cooling performance assessed over a range of thermal loads and experimental conditions. Tests were performed for different values of coolant flow rate, channel spacing, panel thermal conductivity, and applied heat flux. More efficient cooling occurs when the coolant flow rate is increased, channel spacing is reduced, and thermal conductivity of the host composite is increased. Computational fluid dynamics (CFD) simulations were also performed and correlate well with the experimental data. CFD simulations of a typical EV battery pack confirm that microvascular composite panels can adequately cool battery cells generating 500 W m-2 heat flux below 40 °C.

Cooling the Origins Space Telescope

NASA Technical Reports Server (NTRS)

Dipirro, M.; Canavan, E.; Fantano, L.

2017-01-01

The NASA Astrophysics Division has commissioned 4 studies for consideration by the 2020 Decadal Survey to be the next flagship mission following WFIRST (Wide Field Infrared Survey Telescope). One of the four studies is the Origins Space Telescope (OST), which will cover wavelengths from 6 microns to 600 microns. To perform at the level of the zodiacal, galactic, and cosmic background, the telescope must be cooled to 4 degrees Kelvin. 4 degrees Kelvin multi-stage mechanical cryocoolers will be employed along with a multilayer sunshield/thermal shield to achieve this temperature with a manageable parasitic heat load. Current state-of-the-art cryocoolers can achieve close to 4 degrees Kelvin, providing about 50 megawatts of cooling at 4 degrees Kelvin with an input power of 500 watts. Multiple coolers at this power level will be used in parallel. These coolers also provide extra cooling power at intermediate temperature stages of 15-20 degrees Kelvin and 50-70 degrees Kelvin . This upper stage cooling will be used to limit the heat conducted to 4 degrees Kelvin . The multi-layer sunshield will limit the radiated thermal energy to the 4 degrees Kelvin volume. This paper will describe the architecture of the cryogenic system for OST along with preliminary thermal models.

Personal cooling in hot workings

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

Tuck, M.A.

1999-07-01

The number of mines experiencing climatic difficulties worldwide is increasing. In a large number of cases these climatic difficulties are confined to working areas only or to specific locations within working areas. Thus the problem in these mines can be described as highly localized, due to a large extent not to high rock temperatures but due to machine heat loads and low airflow rates. Under such situations conventional means of controlling the climate can be inapplicable and/or uneconomic. One possible means of achieving the required level of climatic control, to ensure worker health and safety whilst achieving economic gains, ismore » to adopt a system of active man cooling. This is the reverse of normal control techniques where the cooling power of the ventilating air is enhanced in some way. Current methods of active man cooling include ice jackets and various umbilical cord type systems. These have numerous drawbacks, such as limited useful exposure times and limitations to worker mobility. The paper suggests an alternative method of active man cooling than those currently available and reviews the design criteria for such a garment. The range of application of such a garment is discussed, under both normal and emergency situations.« less

Field-Based Pre-Cooling for On-Court Tennis Conditioning Training in the Heat

PubMed Central

Duffield, Rob; Bird, Stephen P.; Ballard, Robert J.

2011-01-01

The present study investigated the effects of pre-cooling for on- court, tennis-specific conditioning training in the heat. Eight highly-trained tennis players performed two on-court conditioning sessions in 35°C, 55% Relative Humidity. Sessions were randomised, involved either a pre-cooling or control session, and consisted of 30-min of court- based, tennis movement drills. Pre-cooling involved 20-min of an ice-vest and cold towels to the head/neck and legs, followed by warm-up in a cold compression garment. On-court movement distance was recorded by 1Hz Global Positioning Satellite (GPS) devices, while core temperature, heart rate and perceptual exertion and thermal stress were also recorded throughout the session. Additionally, mass and lower-body peak power during repeated counter-movement jumps were measured before and after each session. No significant performance differences were evident between conditions, although a moderate-large effect (d = 0.7-1.0; p > 0.05) was evident for total (2989 ± 256 v 2870 ± 159m) and high-intensity (805 ± 340 v 629 ± 265m) distance covered following pre-cooling. Further, no significant differences were evident between conditions for rise in core temperature (1.9 ± 0.4 v 2. 2 ± 0.4°C; d > 0.9; p > 0.05), although a significantly smaller change in mass (0.9 ± 0.3 v 1. 3 ± 0.3kg; p < 0.05) was present following pre-cooling. Perceived thermal stress and exertion were significantly lower (d > 1.0; p < 0.05) during the cooling session. Finally, lower-body peak power did not differ between conditions before or after training (d < 0.3; p > 0.05). Conclusions: Despite trends for lowered physiological load and increased distances covered following cooling, the observed responses were not significantly different or as explicit as previously reported laboratory-based pre-cooling research. Key points Pre-cooling did not significantly enhance training performance or reduce physiological load for tennis training in the heat

A Robust Cooling Platform for NIS Junction Refrigeration and sub-Kelvin Cryogenic Systems

NASA Astrophysics Data System (ADS)

Wilson, B.; Atlas, M.; Lowell, P.; Moyerman, S.; Stebor, N.; Ullom, J.; Keating, B.

2014-08-01

Recent advances in Normal metal-insulator-superconductor (NIS) tunnel junctions (Clark et al. Appl Phys Lett 86: 173508, 2005, Appl Phys Lett 84: 4, 2004) have proven these devices to be a viable technology for sub-Kelvin refrigeration. NIS junction coolers, coupled to a separate cold stage, provide a flexible platform for cooling a wide range of user-supplied payloads. Recently, a stage was cooled from 290 to 256 mK (Lowell et al. Appl Phys Lett 102: 082601 2013), but further mechanical and electrical improvements are necessary for the stage to reach its full potential. We have designed and built a new Kevlar suspended cooling platform for NIS junction refrigeration that is both lightweight and well thermally isolated; the calculated parasitic loading is pW from 300 to 100 mK. The platform is structurally rigid with a measured deflection of 25 m under a 2.5 kg load and has an integrated mechanical heat switch driven by a superconducting stepper motor with thermal conductivity G W/K at 300 mK. An integrated radiation shield limits thermal loading and a modular platform accommodates enough junctions to provide nanowatts of continuous cooling power. The compact stage size of 7.6 cm 8.6 cm 4.8 cm and overall radiation shield size of 8.9 cm 10.0 cm 7.0 cm along with minimal electrical power requirements allow easy integration into a range of cryostats. We present the design, construction, and performance of this cooling platform as well as projections for coupling to arrays of NIS junctions and other future applications.

Helical muon beam cooling channel engineering design

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

Johnson, Rolland

The Helical Cooling Channel (HCC) achieves effective ionization cooling of the six-dimensional (6d) phase space of a muon beam by means of a series of 21st century inventions. In the HCC, hydrogen-pressurized RF cavities enable high RF gradients in strong external magnetic fields. The theory of the HCC, which requires a magnetic field with solenoid, helical dipole, and helical quadrupole components, demonstrates that dispersion in the gaseous hydrogen energy absorber provides effective emittance exchange to enable longitudinal ionization cooling. The 10-year development of a practical implementation of a muon-beam cooling device has involved a series of technical innovations and experimentsmore » that imply that an HCC of less than 300 m length can cool the 6d emittance of a muon beam by six orders of magnitude. We describe the design and construction plans for a prototype HCC module based on oxygen-doped hydrogen-pressurized RF cavities that are loaded with dielectric, fed by magnetrons, and operate in a superconducting helical solenoid magnet. The first phase of this project saw the development of a conceptual design for the integration of 805 MHz RF cavities into a 10 T Nb 3Sn-based HS test section. Two very novel ideas are required to realize the design. The first idea is the use of dielectric inserts in the RF cavities to make them smaller for a given frequency so that the cavities and associated plumbing easily fit inside the magnet cryostat. Calculations indicate that heat loads will be tolerable, while RF breakdown of the dielectric inserts will be suppressed by the pressurized hydrogen gas. The second new idea is the use of a multi-layer Nb 3Sn helical solenoid. The technology demonstrations for the two aforementioned key components of a 10T, 805 MHz HCC were begun in this project. The work load in the Fermilab Technical Division made it difficult to test a multi-layer Nb 3Sn solenoid as originally planned. Instead, a complementary project was approved

MEMS Device Being Developed for Active Cooling and Temperature Control

NASA Technical Reports Server (NTRS)

Moran, Matthew E.

2001-01-01

High-capacity cooling options remain limited for many small-scale applications such as microelectronic components, miniature sensors, and microsystems. A microelectromechanical system (MEMS) is currently under development at the NASA Glenn Research Center to meet this need. It uses a thermodynamic cycle to provide cooling or heating directly to a thermally loaded surface. The device can be used strictly in the cooling mode, or it can be switched between cooling and heating modes in milliseconds for precise temperature control. Fabrication and assembly are accomplished by wet etching and wafer bonding techniques routinely used in the semiconductor processing industry. Benefits of the MEMS cooler include scalability to fractions of a millimeter, modularity for increased capacity and staging to low temperatures, simple interfaces and limited failure modes, and minimal induced vibration.

Solar heating and cooling demonstration project at the Florida solar energy center

NASA Technical Reports Server (NTRS)

1980-01-01

The retrofitted solar heating and cooling system installed at the Florida Solar Energy Center is described. The system was designed to supply approximately 70 percent of the annual cooling and 100 percent of the heating load. The project provides unique high temperature, nonimaging, nontracking, evacuated tube collectors. The design of the system was kept simple and employs five hydronic loops. They are energy collection, chilled water production, space cooling, space heating and energy rejection. Information is provided on the system's acceptance test results operation, controls, hardware and installation, including detailed drawings.

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.

Grazing management effects on sediment, phosphorus, and pathogen loading of streams in cool-season grass pastures.

PubMed

Schwarte, Kirk A; Russell, James R; Kovar, John L; Morrical, Daniel G; Ensley, Steven M; Yoon, Kyoung-Jin; Cornick, Nancy A; Cho, Yong Il

2011-01-01

Erosion and runoff from pastures may lead to degradation of surface water. A 2-yr grazing study was conducted to quantify the effects of grazing management on sediment, phosphorus (P), and pathogen loading of streams in cool-season grass pastures. Six adjoining 12.1-ha pastures bisected by a stream in central Iowa were divided into three treatments: continuous stocking with unrestricted stream access (CSU), continuous stocking with restricted stream access (CSR), and rotational stocking (RS). Rainfall simulations on stream banks resulted in greater ( < 0.10) proportions of applied precipitation and amounts of sediment and P transported in runoff from bare sites than from vegetated sites across grazing treatments. Similar differences were observed comparing vegetated sites in CSU and RS pastures with vegetated sites in CSR pastures. Bovine enterovirus was shed by an average of 24.3% of cows during the study period and was collected in the runoff of 8.3 and 16.7% of runoff simulations on bare sites in CSU pastures in June and October of 2008, respectively, and from 8.3% of runoff simulations on vegetated sites in CSU pastures in April 2009. Fecal pathogens (bovine coronavirus [BCV], bovine rotavirus group A, and O157:H7) shed or detected in runoff were almost nonexistent; only BCV was detected in feces of one cow in August of 2008. Erosion of cut-banks was the greatest contributor of sediment and P loading to the stream; contributions from surface runoff and grazing animals were considerably less and were minimized by grazing management practices that reduced congregation of cattle by pasture streams. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Transient Three-Dimensional Analysis of Nozzle Side Load in Regeneratively Cooled Engines

NASA Technical Reports Server (NTRS)

ng, Ten-See

2005-01-01

Nozzle side loads are potentially detrimental to the integrity and life of almost all launch vehicles. the lack of a detailed prediction capability results in reducing life and increased weight for reusable nozzle systems. A clear understanding of the mechanism that contribute to side loads during engine startup, shutdown, and steady-state operations must be established. A CFD based predictive tool must be developed to aid the understanding of side load physics and development of future reusable engine.

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.

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

Strong Electron Self-Cooling in the Cold-Electron Bolometers Designed for CMB Measurements

NASA Astrophysics Data System (ADS)

Kuzmin, L. S.; Pankratov, A. L.; Gordeeva, A. V.; Zbrozhek, V. O.; Revin, L. S.; Shamporov, V. A.; Masi, S.; de Bernardis, P.

2018-03-01

We have realized cold-electron bolometers (CEB) with direct electron self-cooling of the nanoabsorber by SIN (Superconductor-Insulator-Normal metal) tunnel junctions. This electron self-cooling acts as a strong negative electrothermal feedback, improving noise and dynamic properties. Due to this cooling the photon-noise-limited operation of CEBs was realized in array of bolometers developed for the 345 GHz channel of the OLIMPO Balloon Telescope in the power range from 10 pW to 20 pW at phonon temperature Tph =310 mK. The negative electrothermal feedback in CEB is analogous to TES but instead of artificial heating we use cooling of the absorber. The high efficiency of the electron self-cooling to Te =100 mK without power load and to Te=160 mK under power load is achieved by: - a very small volume of the nanoabsorber (0.02 μm3) and a large area of the SIN tunnel junctions, - effective removal of hot quasiparticles by arranging double stock at both sides of the junctions and close position of the normal metal traps, - self-protection of the 2D array of CEBs against interferences by dividing them between N series CEBs (for voltage interferences) and M parallel CEBs (for current interferences), - suppression of Andreev reflection by a thin layer of Fe in the AlFe absorber. As a result even under high power load the CEBs are working at electron temperature Te less than Tph . To our knowledge, there is no analogue in the bolometers technology in the world for bolometers working at electron temperature colder than phonon temperature.

Gas hydrate cool storage system

DOEpatents

Ternes, M.P.; Kedl, R.J.

1984-09-12

The invention presented relates to the development of a process utilizing a gas hydrate as a cool storage medium for alleviating electric load demands during peak usage periods. Several objectives of the invention are mentioned concerning the formation of the gas hydrate as storage material in a thermal energy storage system within a heat pump cycle system. The gas hydrate was formed using a refrigerant in water and an example with R-12 refrigerant is included. (BCS)

Residential load management system

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

Uhr, C.W.

1986-03-01

The MAX load management system marketed by the UHR Corporation is described. The system completely replaces conventional heating, cooling, and hot water equipment. It is designed to reduce significantly the home's peak demand during the electric utility's system-wide peak load periods while at the same time maintain the homeowner's comfort. The integration of microprocessor, thermal storage, and heat pump technologies allows for broad flexibility in terms of tailoring the system to a specific electric utility's needs. Twelve pilot systems installed in Northern Virginia outside of Washington, DC have been operational since early 1985. The test results to date have confirmedmore » both the system's load management capability and its comfort improvement characteristics. The fundamental characteristics and hardware for the system are described. 9 figures.« less

Fabrication of cooled radial turbine rotor

NASA Technical Reports Server (NTRS)

Hammer, A. N.; Aigret, G. G.; Psichogios, T. P.; Rodgers, C.

1986-01-01

A design and fabrication program was conducted to evaluate a unique concept for constructing a cooled, high temperature radial turbine rotor. This concept, called split blade fabrication was developed as an alternative to internal ceramic coring. In this technique, the internal cooling cavity is created without flow dividers or any other detail by a solid (and therefore stronger) ceramic plate which can be more firmly anchored within the casting shell mold than can conventional detailed ceramic cores. Casting is conducted in the conventional manner, except that the finished product, instead of having finished internal cooling passages, is now a split blade. The internal details of the blade are created separately together with a carrier sheet. The inserts are superalloy. Both are produced by essentially the same software such that they are a net fit. The carrier assemblies are loaded into the split blade and the edges sealed by welding. The entire wheel is Hot Isostatic Pressed (HIPed), braze bonding the internal details to the inside of the blades. During this program, two wheels were successfully produced by the split blade fabrication technique.

Site-specific investigations on aquifer thermal energy storage for space and process cooling

NASA Astrophysics Data System (ADS)

Brown, D. R.

1991-08-01

The Pacific Northwest Laboratory (PNL) has completed three preliminary site-specific feasibility studies that investigated aquifer thermal energy storage (ATES) for reducing space and process cooling costs. Chilled water stored in an ATES system could be used to meet all or part of the process and/or space cooling loads at the three facilities investigated. Seasonal or diurnal chill ATES systems could be significantly less expensive than a conventional electrically-driven, load-following chiller system at one of the three sites, depending on the cooling water loop return temperature and presumed future electricity escalation rate. For the other two sites investigated, a chill ATES system would be economically competitive with conventional chillers if onsite aquifer characteristics were improved. Well flow rates at one of the sites were adequate, but the expected thermal recovery efficiency was too low. The reverse of this situation was found at the other site, where the thermal recovery efficiency was expected to be adequate, but well flow rates were too low.

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

An Introduction to ESERO-UK, the UK Space Education Office

ERIC Educational Resources Information Center

Clements, Allan; Mather, Edward

2012-01-01

This article introduces the UK branch of the European Space Education Resource Office (ESERO-UK), also known as the UK Space Education Office. It is a teaching project designed to use space to enthuse primary and secondary students to study science, technology, engineering and mathematics (STEM) subjects. The office is funded by the European Space…

Novel Cooling Strategies for Military Training and Operations.

PubMed

Lee, Jason K W; Kenefick, Robert W; Cheuvront, Samuel N

2015-11-01

The deleterious effects of environmental heat stress, combined with high metabolic loads and protective clothing and equipment of the modern Warfighter, impose severe heat strain, impair task performance, and increase risk of heat illness, thereby reducing the chance for mission success. Despite the implementation of heat-risk mitigation procedures over the past decades, task performance still suffers and exertional heat illness remains a major military problem. We review 3 novel heat mitigation strategies that may be implemented in the training or operational environment to reduce heat strain and the risk of exertional heat illness. These strategies include ingestion of ice slurry, arm immersion cooling, and microclimate cooling. Each of these strategies is suitable for use in different scenarios and the choice of cooling strategy is contingent on the requirements, circumstances, and constraints of the training and operational scenario. Ingestion of ice slurry and arm immersion cooling are practical strategies that may be implemented during training scenarios; ice slurry can be ingested before and during exercise, whereas arm immersion cooling can be administered after exercise-heat exposure. In the operational environment, existing microclimate cooling can be implemented with retrofitted vehicles and as an unmounted system, and it has the potential for use in many military occupational scenarios. This review will discuss the efficacy, limitations, and practical considerations for field implementation of each strategy.

Effects of a New Cooling Technology on Physical Performance in US Air Force Military Personnel.

PubMed

O'Hara, Reginald; Vojta, Christopher; Henry, Amy; Caldwell, Lydia; Wade, Molly; Swanton, Stacie; Linderman, Jon K; Ordway, Jason

2016-01-01

Heat-related illness is a critical factor for military personnel operating in hyperthermic environments. Heat illness can alter cognitive and physical performance during sustained operations missions. Therefore, the primary purpose of this investigation was to determine the effects of a novel cooling shirt on core body temperature in highly trained US Air Force personnel. Twelve trained (at least 80th percentile for aerobic fitness according to the American College of Sports Medicine, at least 90% on the US Air Force fitness test), male Air Force participants (mean values: age, 25 ± 2.8 years; height, 178 ± 7.9cm; body weight 78 ± 9.6kg; maximal oxygen uptake, 57 ± 1.9mL/kg/ min; and body fat, 10% ± 0.03%) completed this study. Subjects performed a 70-minute weighted treadmill walking test and 10-minute, 22.7kg sandbag shuttle test under two conditions: (1) "loaded" (shirt with cooling inserts) and (2) "unloaded" (shirt with no cooling inserts). Core body temperature, exercise heart rate, capillary blood lactate, and ratings of perceived exertion were recorded. Core body temperature was lower (ρ = .001) during the 70-minute treadmill walking test in the loaded condition. Peak core temperature during the 70-minute walking test was also significantly lower (ρ = .038) in the loaded condition. This lightweight (471g), passive cooling technology offers multiple hours of sustained cooling and reduced core and peak body temperature during a 70-minute, 22.7kg weighted-vest walking test. 2016.

Evaluating Moisture Control of Variable-Capacity Heat Pumps in Mechanically Ventilated, Low-Load Homes in Climate Zone 2A

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

Martin, Eric; Withers, Chuck; McIlvaine, Janet

The well-sealed, highly insulated building enclosures constructed by today's home building industry coupled with efficient lighting and appliances are achieving significantly reduced heating and cooling loads. These low-load homes can present a challenge when selecting appropriate space-conditioning equipment. Conventional, fixed-capacity heating and cooling equipment is often oversized for small homes, causing increased first costs and operating costs. Even if fixed-capacity equipment can be properly specified for peak loads, it remains oversized for use during much of the year. During these part-load cooling hours, oversized equipment meets the target dry-bulb temperatures very quickly, often without sufficient opportunity for moisture control. Themore » problem becomes more acute for high-performance houses in humid climates when meeting ASHRAE Standard 62.2 recommendations for wholehouse mechanical ventilation.« less

Transient Three-Dimensional Analysis of Side Load in Liquid Rocket Engine Nozzles

NASA Technical Reports Server (NTRS)

Wang, Ten-See

2004-01-01

Three-dimensional numerical investigations on the nozzle start-up side load physics were performed. The objective of this study is 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, and pressure-based computational fluid dynamics formulation, and a simulated inlet condition based on a system calculation. Finite-rate chemistry was used throughout the study so that combustion effect is always included, and the effect of wall cooling on side load physics is studied. The side load physics captured include the afterburning wave, transition from free- shock to restricted-shock separation, and lip Lambda shock oscillation. With the adiabatic nozzle, free-shock separation reappears after the transition from free-shock separation to restricted-shock separation, and the subsequent flow pattern of the simultaneous free-shock and restricted-shock separations creates a very asymmetric Mach disk flow. With the cooled nozzle, the more symmetric restricted-shock separation persisted throughout the start-up transient after the transition, leading to an overall lower side load than that of the adiabatic nozzle. The tepee structures corresponding to the maximum side load were addressed.

Effect of density and weight of load on the energy cost of carrying loads by donkeys and ponies.

PubMed

Pearson, R A; Dijkman, J T; Krecek, R C; Wright, P

1998-02-01

Two experiments were designed to compare the energy used in carrying loads by donkeys and ponies. In the first experiment 3 donkeys and 3 ponies were compared on treadmills in the UK. Density of load (lead shot or straw) had no significant effect on the energy cost of carrying loads; however, the energy cost of carrying a load decreased significantly (p < 0.001) as the weight of the load increased (in donkeys 6.44, 4.35 and 3.03 J/kg load/m, in ponies 5.82, 3.75 and 3.68 J/kg load/m, for loads of 13, 20 and 27 kg/100 kg liveweight (M) respectively). Differences between species were not significant. In the second experiment energy expenditures were determined in 3 donkeys carrying loads equivalent to 40 kg/100 kg M over gently undulating gravel tracks in Tunisia. Energy costs of carrying the load were 2.34 (SE 0.07) J/kg load/m. The results of both experiments showed that provided the load is balanced, density does not significantly affect the energy cost of carrying; however, as the load increased then the unit energy cost of carrying it decreased. This suggest that it is more efficient in terms of energy used to carry loads equivalent to 27 to 40 kg/100 kg M than it is to carry lighter loads to less than 20 kg/100 kg M.

Non-Evaporative Cooling via Inelastic Collisions in an Optical Trap

DTIC Science & Technology

2013-02-28

Simultaneous loading of 85 Rb and 87 Rb into an optical trap from a Magneto - optic Trap (MOT) As was mentioned in the previous section, when both...potential in an 85 Rb magneto - optical trap , Phys. Rev. A 83, 033419 (2011) I.D Ultracold plasma response to few-cycle rf pulses As will be detailed in...ultracold atoms of each isotope were cooled into overlapping Magneto - optic Traps (MOTs). From there, the atoms were then loaded into a Far-off

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 the beam screen cooling for the Future Circular Collider of hadron beams

NASA Astrophysics Data System (ADS)

Kotnig, C.; Tavian, L.

2015-12-01

Following recommendations of the recent update of the European strategy in particle physics, CERN has undertaken an international study of possible future circular colliders beyond the LHC. This study considers an option for a very high energy (100 TeV) hadron-hadron collider located in a quasi-circular underground tunnel having a circumference of 80 to 100 km. The synchrotron radiation emitted by the high-energy hadron beam increases by more than two orders of magnitude compared to the LHC. To reduce the entropic load on the superconducting magnets’ refrigeration system, beam screens are indispensable to extract the heat load at a higher temperature level. After illustrating the decisive constraints of the beam screen's refrigeration design, this paper presents a preliminary design of the length of a continuous cooling loop comparing helium and neon, for different cooling channel geometries with emphasis on the cooling length limitations and the exergetic efficiency.

Simulation of cooling efficiency via miniaturised channels in multilayer LTCC for power electronics

NASA Astrophysics Data System (ADS)

Pietrikova, Alena; Girasek, Tomas; Lukacs, Peter; Welker, Tilo; Müller, Jens

2017-03-01

The aim of this paper is detailed investigation of thermal resistance, flow analysis and distribution of coolant as well as thermal distribution inside multilayer LTCC substrates with embedded channels for power electronic devices by simulation software. For this reason four various structures of internal channels in the multilayer LTCC substrates were designed and simulated. The impact of the volume flow, structures of channels, and power loss of chip was simulated, calculated and analyzed by using the simulation software Mentor Graphics FloEFDTM. The structure, size and location of channels have the significant impact on thermal resistance, pressure of coolant as well as the effectivity of cooling power components (chips) that can be placed on the top of LTCC substrate. The main contribution of this paper is thermal analyze, optimization and impact of 4 various cooling channels embedded in LTCC multilayer structure. Paper investigate, the effect of volume flow in cooling channels for achieving the least thermal resistance of LTCC substrate that is loaded by power thermal chips. Paper shows on the impact of the first chips thermal load on the second chip as well as. This possible new technology could ensure in the case of practical realization effective cooling and increasing reliability of high power modules.

Performance of the Conduction-Cooled LDX Levitation Coil

NASA Astrophysics Data System (ADS)

Michael, P. C.; Schultz, J. H.; Smith, B. A.; Titus, P. H.; Radovinsky, A.; Zhukovsky, A.; Hwang, K. P.; Naumovich, G. J.; Camille, R. J.

2004-06-01

The Levitated Dipole Experiment (LDX) was developed to study plasma confinement in a dipole magnetic field. Plasma is confined in the magnetic field of a 680-kg Nb3Sn Floating Coil (F-coil) that is electromagnetically supported at the center of a 5-m diameter by 3-m tall vacuum chamber. The Levitation Coil (L-coil) is a 2800-turn, double pancake winding that supports the weight of the F-coil and controls its vertical position within the vacuum chamber. The use of high-temperature superconductor (HTS) Bi-2223 for the L-coil minimizes the electrical and cooling power needed for levitation. The L-coil winding pack and support plate are suspended within the L-coil cryostat and cooled by conduction to a single-stage cryocooler rated for 25-W heat load at approximately 20 K. The coil current leads consist of conduction-cooled copper running from room temperature to 80 K and a pair of commercially-available, 150-A HTS leads. An automatically filled liquid-nitrogen reservoir provides cooling for the coil's radiation shield and for the leads' 80-K heat stations. This paper discusses the L-coil system design and its observed cryogenic performance.

Flow directing means for air-cooled transformers

DOEpatents

Jallouk, Philip A.

1977-01-01

This invention relates to improvements in systems for force-cooling transformers of the kind in which an outer helical winding and an insulation barrier nested therein form an axially extending annular passage for cooling-fluid flow. In one form of the invention a tubular shroud is positioned about the helical winding to define an axially extending annular chamber for cooling-fluid flow. The chamber has a width in the range of from about 4 to 25 times that of the axially extending passage. Two baffles extend inward from the shroud to define with the helical winding two annular flow channels having hydraulic diameters smaller than that of the chamber. The inlet to the chamber is designed with a hydraulic diameter approximating that of the coolant-entrance end of the above-mentioned annular passage. As so modified, transformers of the kind described can be operated at significantly higher load levels without exceeding safe operating temperatures. In some instances the invention permits continuous operation at 200% of the nameplate rating.

Study on load forecasting to data centers of high power density based on power usage effectiveness

NASA Astrophysics Data System (ADS)

Zhou, C. C.; Zhang, F.; Yuan, Z.; Zhou, L. M.; Wang, F. M.; Li, W.; Yang, J. H.

2016-08-01

There is usually considerable energy consumption in data centers. Load forecasting to data centers is in favor of formulating regional load density indexes and of great benefit to getting regional spatial load forecasting more accurately. The building structure and the other influential factors, i.e. equipment, geographic and climatic conditions, are considered for the data centers, and a method to forecast the load of the data centers based on power usage effectiveness is proposed. The cooling capacity of a data center and the index of the power usage effectiveness are used to forecast the power load of the data center in the method. The cooling capacity is obtained by calculating the heat load of the data center. The index is estimated using the group decision-making method of mixed language information. An example is given to prove the applicability and accuracy of this method.

Cycle Design of Reverse Brayton Cryocooler for HTS Cable Cooling Using Exergy Analysis

NASA Astrophysics Data System (ADS)

Gupta, Sudeep Kumar; Ghosh, Parthasarathi

2017-02-01

The reliability and price of cryogenic refrigeration play an important role in the successful commercialization of High Temperature Superconducting (HTS) cables. For cooling HTS cable, sub-cooled liquid nitrogen (LN2) circulation system is used. One of the options to maintain LN2 in its sub-cooled state is by providing refrigeration with the help of Reverse Brayton Cryo-cooler (RBC). The refrigeration requirement is 10 kW for continuously sub-cooling LN2 from 72 K to 65 K for cooling 1 km length of HTS cable [1]. In this paper, a parametric evaluation of RBC for sub-cooling LN2 has been performed using helium as a process fluid. Exergy approach has been adopted for this analysis. A commercial process simulator, Aspen HYSYS® V8.6 has been used for this purpose. The critical components have been identified and their exergy destruction and exergy efficiency have been obtained for a given heat load condition.

Thermal deformation of cryogenically cooled silicon crystals under intense X-ray beams: measurement and finite-element predictions of the surface shape

PubMed Central

Zhang, Lin; Sánchez del Río, Manuel; Monaco, Giulio; Detlefs, Carsten; Roth, Thomas; Chumakov, Aleksandr I.; Glatzel, Pieter

2013-01-01

X-ray crystal monochromators exposed to white-beam X-rays in third-generation synchrotron light sources are subject to thermal deformations that must be minimized using an adequate cooling system. A new approach was used to measure the crystal shape profile and slope of several cryogenically cooled (liquid nitrogen) silicon monochromators as a function of beam power in situ and under heat load. The method utilizes multiple angular scans across the Bragg peak (rocking curve) at various vertical positions of a narrow-gap slit downstream from the monochromator. When increasing the beam power, the surface of the liquid-nitrogen-cooled silicon crystal deforms from a concave shape at low heat load to a convex shape at high heat load, passing through an approximately flat shape at intermediate heat load. Finite-element analysis is used to calculate the crystal thermal deformations. The simulated crystal profiles and slopes are in excellent agreement with experiments. The parameters used in simulations, such as material properties, absorbed power distribution on the crystal and cooling boundary conditions, are described in detail as they are fundamental for obtaining accurate results. PMID:23765298

The Impact of Vocal Cool-down Exercises: A Subjective Study of Singers' and Listeners' Perceptions.

PubMed

Ragan, Kari

2016-11-01

Using subjective measures, this study investigated singers' and listeners' perceptions of changes in voice condition after vocal cool-down exercises. A single-subject crossover was designed to evaluate whether there were discernible differences in either singer or listener perceptions from pre (no vocal cool downs) to post (with cool downs) test. Subjective questionnaires were completed throughout the study. Twenty classically trained female singers documented self-ratings and perceptual judgments through the Evaluation of the Ability to Sing Easily survey, the Singing Voice Handicap Index, and Self-Perceptual Questionnaires after a 60-minute voice load. Recordings were made and assessed by four expert listeners. The assessed data from the Singing Voice Handicap Index, the Evaluation of the Ability to Sing Easily, and Daily Perceptual Questionnaires show 68%, 67%, and 74% of singers reported improvement, respectively. However, because of significant variability in the underlying scores, the amount of improvement was not deemed to be statistically significant. Expert listeners correctly identified the cool-down week 46% of the time. Singers strongly perceived positive impact from the cool-down exercises on both their speaking and singing voices. Even though the objective data were statistically insignificant, the singers' subjective data clearly indicates a perceived sense of vocal well-being after utilizing the vocal cool-down protocol. The variability in the daily life of a singer (eg, stress, menses, reflux, vocal load, and vocal hygiene) makes it difficult to objectively quantify the impact of vocal cool downs. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Mechanical design of experimental apparatus for FIREX cryo-target cooling

NASA Astrophysics Data System (ADS)

Iwamoto, A.; Norimatsu, T.; Nakai, M.; Sakagami, H.; Fujioka, S.; Shiraga, H.; Azechi, H.

2016-05-01

Mechanical design of an experimental apparatus for FIREX cryo-target cooling is described. Gaseous helium (GHe) sealing system at a cryogenic environment is an important issue for laser fusion experiments. The dedicated loading system was designed for a metal gasket. We take U-TIGHTSEAL® (Usui Kokusai Sangyo Kaisha. Ltd.) with an indium plated copper jacket as an example. According to its specification, a linear load of 110 N/m along its circumference is the optimum compression; however a lower load would still maintain helium (He) leak below the required level. Its sealing performance was investigated systematically. Our system demanded 27 N/mm of the load to keep He leak tightness in a cryogenic environment. Once leak tightness was obtained, it could be reduced to 9.5 N/mm.

Lubrication and cooling for high speed gears

NASA Technical Reports Server (NTRS)

Townsend, D. P.

1985-01-01

The problems and failures occurring with the operation of high speed gears are discussed. The gearing losses associated with high speed gearing such as tooth mesh friction, bearing friction, churning, and windage are discussed with various ways shown to help reduce these losses and thereby improve efficiency. Several different methods of oil jet lubrication for high speed gearing are given such as into mesh, out of mesh, and radial jet lubrication. The experiments and analytical results for the various methods of oil jet lubrication are shown with the strengths and weaknesses of each method discussed. The analytical and experimental results of gear lubrication and cooling at various test conditions are presented. These results show the very definite need of improved methods of gear cooling at high speed and high load conditions.

A 1.8K refrigeration cryostat with 100 hours continuous cooling

NASA Astrophysics Data System (ADS)

Xu, Dong; Li, Jian; Huang, Rongjin; Li, Laifeng

2017-02-01

A refrigeration cryostat has been developed to produce continuous cooling to a sample below 1.8 K over 100 hours by using a cryocooler. A two-stage 4K G-M cryocooler is used to liquefy helium gas from evacuated vapor and cylinder helium bottle which can be replaced during the cooling process. The liquid helium transfer into superfluid helium in a Joule-Thomson valve in connection with a 1000 m3/h pumping unit. The pressure of evacuated helium vapor is controlled by air bag and valves. A copper decompression chamber, which is designed as a cooling station to control the superfluid helium, is used to cool the sample attached on it uniformly. The sample connects to the copper chamber in cryostat with screw thread. The cryostat can reach the temperature of 1.7 K without load and the continuous working time is more than 100 hours.

The Effectiveness of Trace DNA Profiling-A Comparison Between a U.S. and a U.K. Law Enforcement Jurisdiction.

PubMed

Bond, John W; Weart, Jocelyn R

2017-05-01

Recovery, profiling, and speculative searching of trace DNA (not attributable to a body fluid/cell type) over a twelve-month period in a U.S. Crime Laboratory and U.K. police force are compared. Results show greater numbers of U.S. firearm-related items submitted for analysis compared with the U.K., where greatest numbers were submitted from burglary or vehicle offenses. U.S. multiple recovery techniques (double swabbing) occurred mainly during laboratory examination, whereas the majority of U.K. multiple recovery techniques occurred at the scene. No statistical difference was observed for useful profiles from single or multiple recovery. Database loading of interpretable profiles was most successful for U.K. items related to burglary or vehicle offenses. Database associations (matches) represented 7.0% of all U.S. items and 13.1% of all U.K. items. The U.K. strategy for burglary and vehicle examination demonstrated that careful selection of both items and sampling techniques is crucial to obtaining the observed results. © 2016 American Academy of Forensic Sciences.

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.

Development of a self-managed loaded exercise programme for rotator cuff tendinopathy.

PubMed

Littlewood, Chris; Malliaras, Peter; Mawson, Sue; May, Stephen; Walters, Stephen

2013-12-01

This paper describes a self-managed loaded exercise programme which has been designed to address the pain and disability associated with rotator cuff tendinopathy. The intervention has been developed with reference to current self-management theory and with reference to the emerging benefit of loaded exercise for tendinopathy. This self-managed loaded exercise programme is being evaluated within the mixed methods SELF study (ISRCTN 84709751) which includes a pragmatic randomised controlled trial conducted within the UK National Health Service. Copyright © 2012 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Design Concepts for Cooled Ceramic Matrix Composite Turbine Vanes

NASA Technical Reports Server (NTRS)

Boyle, Robert

2014-01-01

This project demonstrated that higher temperature capabilities of ceramic matrix composites (CMCs) can be used to reduce emissions and improve fuel consumption in gas turbine engines. The work involved closely coupling aerothermal and structural analyses for the first-stage vane of a high-pressure turbine (HPT). These vanes are actively cooled, typically using film cooling. Ceramic materials have structural and thermal properties different from conventional metals used for the first-stage HPT vane. This project identified vane configurations that satisfy CMC structural strength and life constraints while maintaining vane aerodynamic efficiency and reducing vane cooling to improve engine performance and reduce emissions. The project examined modifications to vane internal configurations to achieve the desired objectives. Thermal and pressure stresses are equally important, and both were analyzed using an ANSYS® structural analysis. Three-dimensional fluid and heat transfer analyses were used to determine vane aerodynamic performance and heat load distributions.

Cryogenic performance of a conduction-cooling splittable quadrupole magnet for ILC cryomodules

NASA Astrophysics Data System (ADS)

Kimura, N.; Andreev, N.; Kashikhin, V. S.; Kerby, J.; Takahashi, M.; Tartaglia, M. A.; Tosaka, T.; Yamamoto, A.

2014-01-01

A conduction-cooled splittable superconducting quadrupole magnet was designed and fabricated at Fermilab for use in cryomodules of the International Linear Collider (ILC) type, in which the magnet was to be assembled around the beam tube to avoid contaminating the ultraclean superconducting radio frequency cavity volume. This quadrupole was first tested in a liquid helium bath environment at Fermilab, where its quench and magnetic properties were characterized. Because the device is to be cooled by conduction when installed in cryomodules, a separate test with a conduction-cooled configuration was planned at KEK and Fermilab. The magnet was converted to a conduction-cooled configuration by adding conduction-cooling passages made of high-purity aluminum. Efforts to convert and refabricate the magnet into a cryostat equipped with a double-stage pulse-tube-type cryocooler began in 2011, and a thermal performance test, including a magnet excitation test of up to 30 A, was conducted at KEK. In this test, the magnet with the conduction-cooled configuration was successfully cooled to 4 K within 190 h, with an acceptable heat load of less than 1 W at 4 K. It was also confirmed that the conduction-cooled splittable superconducting quadrupole magnet was practical for use in ILC-type cryomodules.

PLAB and UK graduates' performance on MRCP(UK) and MRCGP examinations: data linkage study.

PubMed

McManus, I C; Wakeford, Richard

2014-04-17

To assess whether international medical graduates passing the two examinations set by the Professional and Linguistic Assessments Board (PLAB1 and PLAB2) of the General Medical Council (GMC) are equivalent to UK graduates at the end of the first foundation year of medical training (F1), as the GMC requires, and if not, to assess what changes in the PLAB pass marks might produce equivalence. Data linkage of GMC PLAB performance data with data from the Royal Colleges of Physicians and the Royal College of General Practitioners on performance of PLAB graduates and UK graduates at the MRCP(UK) and MRCGP examinations. Doctors in training for internal medicine or general practice in the United Kingdom. 7829, 5135, and 4387 PLAB graduates on their first attempt at MRCP(UK) Part 1, Part 2, and PACES assessments from 2001 to 2012 compared with 18,532, 14,094, and 14,376 UK graduates taking the same assessments; 3160 PLAB1 graduates making their first attempt at the MRCGP AKT during 2007-12 compared with 14,235 UK graduates; and 1411 PLAB2 graduates making their first attempt at the MRCGP CSA during 2010-12 compared with 6935 UK graduates. Performance at MRCP(UK) Part 1, Part 2, and PACES assessments, and MRCGP AKT and CSA assessments in relation to performance on PLAB1 and PLAB2 assessments, as well as to International English Language Testing System (IELTS) scores. MRCP(UK), MRCGP, and PLAB results were analysed as marks relative to the pass mark at the first attempt. PLAB1 marks were a valid predictor of MRCP(UK) Part 1, MRCP(UK) Part 2, and MRCGP AKT (r=0.521, 0.390, and 0.490; all P<0.001). PLAB2 marks correlated with MRCP(UK) PACES and MRCGP CSA (r=0.274, 0.321; both P<0.001). PLAB graduates had significantly lower MRCP(UK) and MRCGP assessments (Glass's Δ=0.94, 0.91, 1.40, 1.01, and 1.82 for MRCP(UK) Part 1, Part 2, and PACES and MRCGP AKT and CSA), and were more likely to fail assessments and to progress more slowly than UK medical graduates. IELTS scores correlated

PLAB and UK graduates’ performance on MRCP(UK) and MRCGP examinations: data linkage study

PubMed Central

Wakeford, Richard

2014-01-01

Objectives To assess whether international medical graduates passing the two examinations set by the Professional and Linguistic Assessments Board (PLAB1 and PLAB2) of the General Medical Council (GMC) are equivalent to UK graduates at the end of the first foundation year of medical training (F1), as the GMC requires, and if not, to assess what changes in the PLAB pass marks might produce equivalence. Design Data linkage of GMC PLAB performance data with data from the Royal Colleges of Physicians and the Royal College of General Practitioners on performance of PLAB graduates and UK graduates at the MRCP(UK) and MRCGP examinations. Setting Doctors in training for internal medicine or general practice in the United Kingdom. Participants 7829, 5135, and 4387 PLAB graduates on their first attempt at MRCP(UK) Part 1, Part 2, and PACES assessments from 2001 to 2012 compared with 18 532, 14 094, and 14 376 UK graduates taking the same assessments; 3160 PLAB1 graduates making their first attempt at the MRCGP AKT during 2007-12 compared with 14 235 UK graduates; and 1411 PLAB2 graduates making their first attempt at the MRCGP CSA during 2010-12 compared with 6935 UK graduates. Main outcome measures Performance at MRCP(UK) Part 1, Part 2, and PACES assessments, and MRCGP AKT and CSA assessments in relation to performance on PLAB1 and PLAB2 assessments, as well as to International English Language Testing System (IELTS) scores. MRCP(UK), MRCGP, and PLAB results were analysed as marks relative to the pass mark at the first attempt. Results PLAB1 marks were a valid predictor of MRCP(UK) Part 1, MRCP(UK) Part 2, and MRCGP AKT (r=0.521, 0.390, and 0.490; all P<0.001). PLAB2 marks correlated with MRCP(UK) PACES and MRCGP CSA (r=0.274, 0.321; both P<0.001). PLAB graduates had significantly lower MRCP(UK) and MRCGP assessments (Glass’s Δ=0.94, 0.91, 1.40, 1.01, and 1.82 for MRCP(UK) Part 1, Part 2, and PACES and MRCGP AKT and CSA), and were more likely to fail assessments

Chance UK

ERIC Educational Resources Information Center

McGrath, Gracia

2003-01-01

Chance UK is a unique charity in the UK that specialises in mentoring programmes for primary schoolchildren with behavioural problems. It was founded in 1995 by a policeman, Chief Superintendent Paul Mathias, who believed that by stepping in early, young children with behavioural difficulties could be given the chance to develop the necessary…

Microbial analysis of meatballs cooled with vacuum and conventional cooling.

PubMed

Ozturk, Hande Mutlu; Ozturk, Harun Kemal; Koçar, Gunnur

2017-08-01

Vacuum cooling is a rapid evaporative cooling technique and can be used for pre-cooling of leafy vegetables, mushroom, bakery, fishery, sauces, cooked food, meat and particulate foods. The aim of this study was to apply the vacuum cooling and the conventional cooling techniques for the cooling of the meatball and to show the vacuum pressure effect on the cooling time, the temperature decrease and microbial growth rate. The results of the vacuum cooling and the conventional cooling (cooling in the refrigerator) were compared with each other for different temperatures. The study shows that the conventional cooling was much slower than the vacuum cooling. Moreover, the microbial growth rate of the vacuum cooling was extremely low compared with the conventional cooling. Thus, the lowest microbial growth occurred at 0.7 kPa and the highest microbial growth was observed at 1.5 kPa for the vacuum cooling. The mass loss ratio for the conventional cooling and vacuum cooling was about 5 and 9% respectively.

Aero-Thermo-Structural Design Optimization of Internally Cooled Turbine Blades

NASA Technical Reports Server (NTRS)

Dulikravich, G. S.; Martin, T. J.; Dennis, B. H.; Lee, E.; Han, Z.-X.

1999-01-01

A set of robust and computationally affordable inverse shape design and automatic constrained optimization tools have been developed for the improved performance of internally cooled gas turbine blades. The design methods are applicable to the aerodynamics, heat transfer, and thermoelasticity aspects of the turbine blade. Maximum use of the existing proven disciplinary analysis codes is possible with this design approach. Preliminary computational results demonstrate possibilities to design blades with minimized total pressure loss and maximized aerodynamic loading. At the same time, these blades are capable of sustaining significantly higher inlet hot gas temperatures while requiring remarkably lower coolant mass flow rates. These results suggest that it is possible to design internally cooled turbine blades that will cost less to manufacture, will have longer life span, and will perform as good, if not better than, film cooled turbine blades.

Experimental parametric study of servers cooling management in data centers buildings

NASA Astrophysics Data System (ADS)

Nada, S. A.; Elfeky, K. E.; Attia, Ali M. A.; Alshaer, W. G.

2017-06-01

A parametric study of air flow and cooling management of data centers servers is experimentally conducted for different design conditions. A physical scale model of data center accommodating one rack of four servers was designed and constructed for testing purposes. Front and rear rack and server's temperatures distributions and supply/return heat indices (SHI/RHI) are used to evaluate data center thermal performance. Experiments were conducted to parametrically study the effects of perforated tiles opening ratio, servers power load variation and rack power density. The results showed that (1) perforated tile of 25% opening ratio provides the best results among the other opening ratios, (2) optimum benefit of cold air in servers cooling is obtained at uniformly power loading of servers (3) increasing power density decrease air re-circulation but increase air bypass and servers temperature. The present results are compared with previous experimental and CFD results and fair agreement was found.

Subcontracted activities related to TES for building heating and cooling

NASA Technical Reports Server (NTRS)

Martin, J.

1980-01-01

The subcontract program elements related to thermal energy storage for building heating and cooling systems are outlined. The following factors are included: subcontracts in the utility load management application area; life and stability testing of packaged low cost energy storage materials; and development of thermal energy storage systems for residential space cooling. Resistance storage heater component development, demonstration of storage heater systems for residential applications, and simulation and evaluation of latent heat thermal energy storage (heat pump systems) are also discussed. Application of thermal energy storage for solar application and twin cities district heating are covered including an application analysis and technology assessment of thermal energy storage.

Cooling performance and evaluation of automotive refrigeration system for a passenger car

NASA Astrophysics Data System (ADS)

Prajitno, Deendarlianto, Majid, Akmal Irfan; Mardani, Mahardeka Dhias; Wicaksono, Wendi; Kamal, Samsul; Purwanto, Teguh Pudji; Fauzun

2016-06-01

A new design of automotive refrigeration system for a passenger car was proposed. To ensure less energy consumption and optimal thermal comfort, the performance of the system were evaluated. This current research was aimed to evaluate the refrigeration characteristics of the system for several types of cooling load. In this present study, a four-passenger wagon car with 1500 cc gasoline engine that equipped by a belt driven compressor (BDC) was used as the tested vehicle. To represent the tropical condition, a set of lamps and wind sources are installed around the vehicle. The blower capacity inside a car is varied from 0.015 m/s to 0.027 m/s and the compressor speed is varied at variable 820, 1400, and 2100 rpm at a set temperature of 22°C. A set of thermocouples that combined by data logger were used to measure the temperature distribution. The system uses R-134a as the refrigerant. In order to determine the cooling capacity of the vehicle, two conditions were presented: without passengers and full load conditions. As the results, cooling capacity from any possible heating sources and transient characteristics of temperature in both systems for the cabin, engine, compressor, and condenser are presented in this work. As the load increases, the outlet temperature of evaporator also increases due to the increase of condensed air. This phenomenon also causes the increase of compressor work and compression ratio which associated to the addition of specific volume in compressor inlet.

Heat transfer optimization for air-mist cooling between a stack of parallel plates

NASA Astrophysics Data System (ADS)

Issa, Roy J.

2010-06-01

A theoretical model is developed to predict the upper limit heat transfer between a stack of parallel plates subject to multiphase cooling by air-mist flow. The model predicts the optimal separation distance between the plates based on the development of the boundary layers for small and large separation distances, and for dilute mist conditions. Simulation results show the optimal separation distance to be strongly dependent on the liquid-to-air mass flow rate loading ratio, and reach a limit for a critical loading. For these dilute spray conditions, complete evaporation of the droplets takes place. Simulation results also show the optimal separation distance decreases with the increase in the mist flow rate. The proposed theoretical model shall lead to a better understanding of the design of fins spacing in heat exchangers where multiphase spray cooling is used.

UK-trained junior doctors' intentions to work in UK medicine: questionnaire surveys, three years after graduation

PubMed Central

Surman, Geraldine; Goldacre, Michael J

2017-01-01

Objective To report on the career intentions, three years after qualification, of 12 national cohorts of UK-trained doctors who qualified between 1974 and 2012, and, specifically, to compare recent UK medical graduates’ intentions to work in medicine in the UK with earlier graduates. Design Questionnaire surveys of cohorts of UK medical graduates defined by year of graduation. Setting UK. Participants 30,272 UK medical graduates. Main outcome measures Stated level of intention to pursue a long-term career in medicine in the UK. Results The response rate was 62% (30,272/48,927). We examined responses to the question ‘Apart from temporary visits abroad, do you intend to practise medicine in the United Kingdom for the foreseeable future?' Of doctors from UK homes, 90% had specified that they would ‘definitely or probably’ practise medicine in the UK in the surveys of 1977–1986, 81% in 1996–2011 and 64% in 2015. Those who said that they would probably or definitely not practise medicine in the UK comprised 5% in 1977–1986, 8% in 1996–2011 and 15% in 2015. Most who were not definite about a future career in UK medicine indicated that they would wish to practise medicine outside the UK rather than to leave medicine. Conclusions The wish to remain in UK medical practice in the 2015 survey was unprecedentedly low in this unique series of 40 years of surveys. PMID:29116902

UK-trained junior doctors' intentions to work in UK medicine: questionnaire surveys, three years after graduation.

PubMed

Surman, Geraldine; Goldacre, Michael J; Lambert, Trevor W

2017-12-01

Objective To report on the career intentions, three years after qualification, of 12 national cohorts of UK-trained doctors who qualified between 1974 and 2012, and, specifically, to compare recent UK medical graduates' intentions to work in medicine in the UK with earlier graduates. Design Questionnaire surveys of cohorts of UK medical graduates defined by year of graduation. Setting UK. Participants 30,272 UK medical graduates. Main outcome measures Stated level of intention to pursue a long-term career in medicine in the UK. Results The response rate was 62% (30,272/48,927). We examined responses to the question ' Apart from temporary visits abroad, do you intend to practise medicine in the United Kingdom for the foreseeable future?' Of doctors from UK homes, 90% had specified that they would 'definitely or probably' practise medicine in the UK in the surveys of 1977-1986, 81% in 1996-2011 and 64% in 2015. Those who said that they would probably or definitely not practise medicine in the UK comprised 5% in 1977-1986, 8% in 1996-2011 and 15% in 2015. Most who were not definite about a future career in UK medicine indicated that they would wish to practise medicine outside the UK rather than to leave medicine. Conclusions The wish to remain in UK medical practice in the 2015 survey was unprecedentedly low in this unique series of 40 years of surveys.

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.

Loads Providing Ancillary Services: Review of InternationalExperience-- Technical Appendix: Market Descriptions

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

Grayson Heffner, Charles Goldman, Kintner-Meyer, M; Kirby, Brendan

2007-05-01

In this study, we examine the arrangements for andexperiences of end-use loads providing ancillary services (AS) in fiveelectricity markets: Australia, the United Kingdom (UK), the Nordicmarket, and the ERCOT and PJM markets in the United States. Our objectivein undertaking this review of international experience was to identifyspecific approaches or market designs that have enabled customer loads toeffectively deliver various ancillary services (AS) products. We hopethat this report will contribute to the ongoing discussion in the U.S.and elsewhere regarding what institutional and technical developments areneeded to ensure that customer loads can meaningfully participate in allwholesale electricity markets.

GreenChill Store Certification Protocol for Sub-Cooling Contained on Racks Separate from Refrigeration Equipment

EPA Pesticide Factsheets

Document describes the protocol used to determine the total load and refrigerant charge of stores that have placed all sub-cooling on a rack separate from all other commercial refrigeration equipment.

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.

Promoting SETI in the UK

NASA Astrophysics Data System (ADS)

Penny, Alan

2013-10-01

MEETING REPORT What does the UK presently do in the search for extraterrestrial intelligence and what are the plans for the future? Alan Penny reports on a meeting of UK academics active in SETI, held as sessions in the recent National Astronomy Meeting in Scotland - and the formation of the UK SETI Research Network to promote UK academic work.

Loading Mode and Environment Effects on Surface Profile Characteristics of Martensite Plates in Cu-Based SMAs

NASA Astrophysics Data System (ADS)

Suru, Marius-Gabriel; Paraschiv, Adrian-Liviu; Lohan, Nicoleta Monica; Pricop, Bogdan; Ozkal, Burak; Bujoreanu, Leandru-Gheorghe

2014-07-01

The present work reports the influence of the loading mode provided during training under constant stress, in bending, applied to lamellar specimens of Cu-Zn-Al shape memory alloys (SMAs). During training, the specimens were bent by a load fastened at their free end, while being martensitic at room temperature and they lifted the load by one-way effect (1WE), during heating up to austenitic field. On cooling to martensite field, the lower concave surface of bent specimens was compressed, and during heating it was elongated, being subjected to a series of tension-compression cycles, during heating-cooling, respectively. Conversely, the upper convex surface of bent specimens was elongated during cooling and compressed during heating, being subjected to compression-tension cycles. Furthermore, 2WE-trained actuators were tested by means of a hydraulic installation where, this time heating-cooling cycles were performed in oil conditions. Considering that the lower concave surface of the specimens was kept in compressed state, while the upper convex surface was kept in elongated state, the study reveals the influence of the two loading modes and environments on the width of martensite plates of the specimens trained under various numbers of cycles. In this purpose, Cu-Zn-Al specimens, trained under 100-300-500 cycles, were prepared and analyzed by atomic force microscopy (AFM) as well as optical and scanning electron microscopy (OM and SEM, respectively). The analysis also included AFM micrographs corroborated with statistical evaluations in order to reveal the effects of loading mode (tension or compression) in different environmental conditions of the specimens, on the surface profile characteristics of martensite plates, revealed by electropolishing.

The production of black carbon during managed burning of UK peatlands: could managed burning of peatlands lead to enhanced carbon storage?

NASA Astrophysics Data System (ADS)

Clay, G.; Worrall, F.

2008-12-01

Peatlands are the UK's largest single terrestrial carbon store with carbon stored in UK peatlands than in forests of Britain and France combined. Unlike most northern peatlands in the peat soils of the UK are heavily managed for recreation and agriculture and due to their proximity to major centres of population are under more anthropogenic pressure than most peatlands. A typical management strategy on UK upland peats is the use of managed fire to restrict vegetation. Fires are used upon a 10-25 year rotation and are described as "cool" as they are designed to remove the crown of the vegetation without scorching the litter layer or the underlying soil. In this case the fire destroys primary productivity and limits litter production but produces char. Char is a low volume, highly refractory, high carbon content product while litter is a high volume, decomposable, lower carbon content product. Therefore, the question is if there are fire conditions under which the production of char causes more carbon to be stored in the peat than would have been stored if no fire management had been employed. This study combines field studies of recent managed burns and wildfires along with detailed vegetation studies from a long term monitoring site in order to assess litter, biomass and black carbon production. In the laboratory experimental burns were undertaken in order to assess the amount and controls upon char production and the carbon content of that char. Results of field and laboratory observations are used to model carbon accumulation under a series of fire management scenarios and the modelling shows that cools burns at long rotations could lead to higher carbon storage than if no fire had occurred, further in several cases more carbon accumulation occurred even if less depth of peat was generated.

Home drinking in the UK: trends and causes.

PubMed

Foster, John H; Ferguson, Colin S

2012-01-01

To explore the trend in the UK to consume alcohol at home rather than at licensed premises. A Medline search entering the terms 'home drinking', 'alcohol' and 'adult' covering the period 2000-2011 yielded 48 articles, of which 6 met the criteria to be included in the review. Grey literature including survey and market research data were reviewed. In the UK, since 1970 there has been trend for beer to be consumed at home more often than in licensed premises and that the overall trend towards greater home drinking has increased since 2000. The main reasons given are convenience, cost, safety, autonomy and stress relief. There has also been an increase in the practice known as 'pre-loading' (drinking before going out). Adults who drink mainly at home report that they are aware that they run a risk of higher overall alcohol consumption but tend to play down the possibility that increased consumption may lead to longer-term harm. Home drinking trends may have long-term public health consequences. Greater understanding of the drivers of this trend will help policy-makers to respond to these societal changes.

Comparing Social Stories™ to Cool versus Not Cool

ERIC Educational Resources Information Center

Leaf, Justin B.; Mitchell, Erin; Townley-Cochran, Donna; McEachin, John; Taubman, Mitchell; Leaf, Ronald

2016-01-01

In this study we compared the cool versus not cool procedure to Social Stories™ for teaching various social behaviors to one individual diagnosed with autism spectrum disorder. The researchers randomly assigned three social skills to the cool versus not cool procedure and three social skills to the Social Stories™ procedure. Naturalistic probes…

Solar-powered Rankine heat pump for heating and cooling

NASA Technical Reports Server (NTRS)

Rousseau, J.

1978-01-01

The design, operation and performance of a familyy of solar heating and cooling systems are discussed. The systems feature a reversible heat pump operating with R-11 as the working fluid and using a motor-driven centrifugal compressor. In the cooling mode, solar energy provides the heat source for a Rankine power loop. The system is operational with heat source temperatures ranging from 155 to 220 F; the estimated coefficient of performance is 0.7. In the heating mode, the vapor-cycle heat pump processes solar energy collected at low temperatures (40 to 80 F). The speed of the compressor can be adjusted so that the heat pump capacity matches the load, allowing a seasonal coefficient of performance of about 8 to be attained.

The design of an air-cooled metallic high temperature radial turbine

NASA Technical Reports Server (NTRS)

Snyder, Philip H.; Roelke, Richard J.

1988-01-01

Recent trends in small advanced gas turbine engines call for higher turbine inlet temperatures. Advances in radial turbine technology have opened the way for a cooled metallic radial turbine capable of withstanding turbine inlet temperatures of 2500 F while meeting the challenge of high efficiency in this small flow size range. In response to this need, a small air-cooled radial turbine has been designed utilizing internal blade coolant passages. The coolant flow passage design is uniquely tailored to simultaneously meet rotor cooling needs and rotor fabrication constraints. The rotor flow-path design seeks to realize improved aerodynamic blade loading characteristics and high efficiency while satisfying rotor life requirements. An up-scaled version of the final engine rotor is currently under fabrication and, after instrumentation, will be tested in the warm turbine test facility at the NASA Lewis Research Center.

Film cooling for a closed loop cooled airfoil

DOEpatents

Burdgick, Steven Sebastian; Yu, Yufeng Phillip; Itzel, Gary Michael

2003-01-01

Turbine stator vane segments have radially inner and outer walls with vanes extending therebetween. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. At least one film cooling hole is defined through a wall of at least one of the cavities for flow communication between an interior of the cavity and an exterior of the vane. The film cooling hole(s) are defined adjacent a potential low LCF life region, so that cooling medium that bleeds out through the film cooling hole(s) reduces a thermal gradient in a vicinity thereof, thereby the increase the LCF life of that region.

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.

Fast cool-down coaxial pulse tube microcooler

NASA Astrophysics Data System (ADS)

Nast, T.; Olson, J. R.; Champagne, P.; Roth, E.; Kaldas, G.; Saito, E.; Loung, V.; McCay, B. S.; Kenton, A. C.; Dobbins, C. L.

2016-09-01

We report the development and initial testing of the Lockheed Martin first-article, single-stage, compact, coaxial, Fast Cooldown Pulse Tube Microcryocooler (FC-PTM). The new cryocooler supports cooling requirements for emerging large, high operating temperature (105-150K) infrared focal plane array sensors with nominal cooling loads of 300 mW @105K @293K ambient. This is a sequel development that builds on our inline and coaxial pulse tube microcryocoolers reported at CEC 20137, ICC188,9, and CEC201510. The new FC-PTM and the prior units all share our long life space technology attributes, which typically have 10 year life requirements1. The new prototype microcryocooler builds on the previous development by incorporating cold head design improvements in two key areas: 1) reduced cool-down time and 2) novel repackaging that greatly reduces envelope. The new coldhead and Dewar were significantly redesigned from the earlier versions in order to achieve a cooldown time of 2-3 minutes- a projected requirement for tactical applications. A design approach was devised to reduce the cold head length from 115mm to 55mm, while at the same time reducing cooldown time. We present new FC-PTM performance test measurements with comparisons to our previous pulse-tube microcryocooler measurements and design predictions. The FC-PTM exhibits attractive small size, volume, weight, power and cost (SWaP-C) features with sufficient cooling capacity over required ambient conditions that apply to an increasing variety of space and tactical applications.

Design and Implementation of a Thermal Load Reduction System in a Hyundai PHEV

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

Kreutzer, Cory J; Rugh, John P

Increased market penetration of electric drive vehicles (EDVs) requires overcoming a number of hurdles including limited vehicle range and the elevated cost of EDVs as compared to conventional vehicles. Climate control loads have a significant impact on range, cutting it by over 50% in both cooling and heating conditions. In order to minimize the impact of climate control on EDV range, the National Renewable Energy Laboratory has partnered with Hyundai America and key industry partners to quantify the performance of thermal load reduction technologies on a Hyundai Sonata PHEV. Technologies that impact vehicle cabin heating in cold weather conditions andmore » cabin cooling in warm weather conditions were evaluated. Tests included thermal transient and steady-state periods for all technologies, including the development of a new test methodology to evaluate the performance of occupant thermal conditioning. Heated surfaces and increased insulation demonstrated significant reductions in energy use from steady-state heating, including a 29% - 59% reduction from heated surfaces. Solar control glass packages demonstrated significant reductions in energy use for both transient and steady-state cooling, with up to a 42% reduction in transient and 12.8% reduction in steady-state energy use for the packages evaluated. Technologies that demonstrated significant climate control load reduction were selected for incorporation into a complete thermal load reduction package. The complete package is set to be evaluated in the second phase of the ongoing project.« less

Space Cooling in North America: Market Overview and Future Impacts

DOE PAGES

Baxter, Van D; Khowailed, Gannate; Sikes, Karen; ...

2015-01-01

The North American space cooling market, particularly in the United States, is experiencing shifts in regulatory regimes, population patterns, economic conditions, and consumer preferences-all catalyzed further by rapid technological innovation. Taken together these factors may result in a slight reduction in air conditioning shipments in the short term, however the longer term trends indicate a continuing increase in the number of air conditioning systems in the U.S. markets. These increases will be greatest in the warmer and more humid (e.g. higher load demand) regions. This will result in increasing pressure on the U.S. electricity supply system to meet the energymore » peak and consumption demands for building space cooling.« less

Cooling circuit for steam and air-cooled turbine nozzle stage

DOEpatents

Itzel, Gary Michael; Yu, Yufeng

2002-01-01

The turbine vane segment includes inner and outer walls with a vane extending therebetween. The vane includes leading and trailing edge cavities and intermediate cavities. An impingement plate is spaced from the outer wall to impingement-cool the outer wall. Post-impingement cooling air flows through holes in the outer wall to form a thin air-cooling film along the outer wall. Cooling air is supplied an insert sleeve with openings in the leading edge cavity for impingement-cooling the leading edge. Holes through the leading edge afford thin-film cooling about the leading edge. Cooling air is provided the trailing edge cavity and passes through holes in the side walls of the vane for thin-film cooling of the trailing edge. Steam flows through a pair of intermediate cavities for impingement-cooling of the side walls. Post-impingement steam flows to the inner wall for impingement-cooling of the inner wall and returns the post-impingement cooling steam through inserts in other intermediate cavities for impingement-cooling the side walls of the vane.

Serial cooling of a combustor for a gas turbine engine

DOEpatents

Abreu, Mario E.; Kielczyk, Janusz J.

2001-01-01

A combustor for a gas turbine engine uses compressed air to cool a combustor liner and uses at least a portion of the same compressed air for combustion air. A flow diverting mechanism regulates compressed air flow entering a combustion air plenum feeding combustion air to a plurality of fuel nozzles. The flow diverting mechanism adjusts combustion air according to engine loading.

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

Design study of a laser-cooled infrared sensor

DOE PAGES

Hehlen, Markus Peter; Boncher, William Lawrence; Love, Steven Paul

2015-03-10

The performance of a solid-state optical refrigerator is the result of a complex interplay of numerous optical and thermal parameters. We present a first preliminary study of an optical cryocooler using ray-tracing techniques. A numerical optimization identified a non-resonant cavity with astigmatism. This geometry offered more efficient pump absorption by the YLF:10%Yb laser-cooling crystal compared to non-resonant cavities without astigmatism that have been pursued experimentally so far. Ray tracing simulations indicate that ~80% of the incident pump light can absorbed for temperatures down to ~100 K. Calculations of heat loads, cooling power, and net payload heat lift are presented. Theymore » show that it is possible to cool a payload to a range of 90–100 K while producing a net payload heat lift of 80 mW and 300 mW when pumping a YLF:10%Yb crystal with 20 W and 50 W at 1020 nm, respectively. This performance is suited to cool HgCdTe infrared detectors that are used for sensing in the 8–12 μm atmospheric window. While the detector noise would be ~6× greater at 100 K than at 77 K, the laser refrigerator would introduce no vibrations and thus eliminate sources of microphonic noise that are limiting the performance of current systems.« less

Postexercise Cooling Rates in 2 Cooling Jackets

PubMed Central

Brade, Carly; Dawson, Brian; Wallman, Karen; Polglaze, Ted

2010-01-01

Abstract Context: Cooling jackets are a common method for removing stored heat accumulated during exercise. To date, the efficiency and practicality of different types of cooling jackets have received minimal investigation. Objective: To examine whether a cooling jacket containing a phase-change material (PC17) results in more rapid postexercise cooling than a gel cooling jacket and a no-jacket (control) condition. Design: Randomized, counterbalanced design with 3 experimental conditions. Setting: Participants exercised at 75% V̇o2max workload in a hot climate chamber (temperature  =  35.0 ± 1.4°C, relative humidity  =  52 ± 4%) for 30 minutes, followed by postexercise cooling for 30 minutes in cool laboratory conditions (ambient temperature  =  24.9 ± 1.8°C, relative humidity  =  39% ± 10%). Patients or Other Participants: Twelve physically active men (age  =  21.3 ± 1.1 years, height  =  182.7 ± 7.1 cm, body mass  =  76.2 ± 9.5 kg, sum of 6 skinfolds  =  50.5 ± 6.9 mm, body surface area  =  1.98 ± 0.14 m2, V̇o2max  =  49.0 ± 7.0 mL·kg−1·min−1) participated. Intervention(s): Three experimental conditions, consisting of a PC17 jacket, a gel jacket, and no jacket. Main Outcome Measure(s): Core temperature (TC), mean skin temperature (TSk), and TC cooling rate (°C/min). Results: Mean peak TC postexercise was 38.49 ± 0.42°C, 38.57 ± 0.41°C, and 38.55 ± 0.40°C for the PC17 jacket, gel jacket, and control conditions, respectively. No differences were observed in peak TC cooling rates among the PC17 jacket (0.038 ± 0.007°C/min), gel jacket (0.040 ± 0.009°C/min), and control (0.034 ± 0.010°C/min, P > .05) conditions. Between trials, no differences were calculated for mean TSk cooling. Conclusions: Similar cooling rates for all 3 conditions indicate that there is no benefit associated with wearing the PC17 or gel jacket. PMID:20210620

Cooled Ceramic Composite Panel Tested Successfully in Rocket Combustion Facility

NASA Technical Reports Server (NTRS)

Jaskowiak, Martha H.

2003-01-01

Regeneratively cooled ceramic matrix composite (CMC) structures are being considered for use along the walls of the hot-flow paths of rocket-based or turbine-based combined-cycle propulsion systems. They offer the combined benefits of substantial weight savings, higher operating temperatures, and reduced coolant requirements in comparison to components designed with traditional metals. These cooled structures, which use the fuel as the coolant, require materials that can survive aggressive thermal, mechanical, acoustic, and aerodynamic loads while acting as heat exchangers, which can improve the efficiency of the engine. A team effort between the NASA Glenn Research Center, the NASA Marshall Space Flight Center, and various industrial partners has led to the design, development, and fabrication of several types of regeneratively cooled panels. The concepts for these panels range from ultra-lightweight designs that rely only on CMC tubes for coolant containment to more maintainable designs that incorporate metal coolant containment tubes to allow for the rapid assembly or disassembly of the heat exchanger. One of the cooled panels based on an all-CMC design was successfully tested in the rocket combustion facility at Glenn. Testing of the remaining four panels is underway.

Cooling of the North Atlantic by Saharan Dust

NASA Technical Reports Server (NTRS)

Lau, K. M.; Kim, K. M.

2007-01-01

Using aerosol optical depth, sea surface temperature, top-of-the-atmosphere solar radiation flux, and oceanic mixed-layer depth from diverse data sources that include NASA satellites, NCEP reanalysis, in situ observations, as well as long-term dust records from Barbados, we examine the possible relationships between Saharan dust and Atlantic sea surface temperature. Results show that the estimated anomalous cooling pattern of the Atlantic during June 2006 relative to June 2005 due to attenuation of surface solar radiation by Saharan dust remarkably resemble observations, accounting for approximately 30-40% of the observed change in sea surface temperature. Historical data analysis show that there is a robust negative correlation between atmospheric dust loading and Atlantic SST consistent with the notion that increased (decreased) Saharan dust is associated with cooling (warming) of the Atlantic during the early hurricane season (July- August-September).

Micro-scale heat-exchangers for Joule-Thomson cooling.

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

Gross, Andrew John

2014-01-01

This project focused on developing a micro-scale counter flow heat exchangers for Joule-Thomson cooling with the potential for both chip and wafer scale integration. This project is differentiated from previous work by focusing on planar, thin film micromachining instead of bulk materials. A process will be developed for fabricating all the devices mentioned above, allowing for highly integrated micro heat exchangers. The use of thin film dielectrics provides thermal isolation, increasing efficiency of the coolers compared to designs based on bulk materials, and it will allow for wafer-scale fabrication and integration. The process is intended to implement a CFHX asmore » part of a Joule-Thomson cooling system for applications with heat loads less than 1mW. This report presents simulation results and investigation of a fabrication process for such devices.« less

Thirty Years of Near Room Temperature Magnetic Cooling: Where we are Today and Future Prospects

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

K.A. Gschneidner, Jr; V.K. Pecharsky'

2008-05-01

The seminal study by Brown in 1976 showed that it was possible to use the magnetocaloric effect to produce a substantial cooling effect near room temperature. About 15 years later Green et al. built a device which actually cooled a load other than the magnetocaloric material itself and the heat exchange fluid. The major breakthrough, however, occurred in 1997 when the Ames Laboratory/Astronautics proof-of-principle refrigerator showed that magnetic refrigeration was competitive with conventional gas compression cooling. Since then, over 25 magnetic cooling units have been built and tested throughout the world. The current status of near room temperature magnetic coolingmore » is reviewed, including a discussion of the major problems facing commercialization and potential solutions thereof. The future outlook for this revolutionary technology is discussed.« less

Integrative Analysis of Desert Dust Size and Abundance Suggests Less Dust Climate Cooling

NASA Technical Reports Server (NTRS)

Kok, Jasper F.; Ridley, David A.; Zhou, Qing; Miller, Ron L.; Zhao, Chun; Heald, Colette L.; Ward, Daniel S.; Albani, Samuel; Haustein, Karsten

2017-01-01

Desert dust aerosols affect Earths global energy balance through interactions with radiation, clouds, and ecosystems. But the magnitudes of these effects are so uncertain that it remains unclear whether atmospheric dust has a net warming or cooling effect on global climate. Consequently, it is still uncertain whether large changes in atmospheric dust loading over the past century have slowed or accelerated anthropogenic climate change, and the climate impact of possible future alterations in dust loading is similarly disputed. Here we use an integrative analysis of dust aerosol sizes and abundance to constrain the climatic impact of dust through direct interactions with radiation. Using a combination of observational, experimental, and model data, we find that atmospheric dust is substantially coarser than represented in current climate models. Since coarse dust warms global climate, the dust direct radiative effect (DRE) is likely less cooling than the 0.4 W m superscript 2 estimated by models in a current ensemble. We constrain the dust DRE to -0.20 (-0.48 to +0.20) W m superscript 2, which suggests that the dust DRE produces only about half the cooling that current models estimate, and raises the possibility that dust DRE is actually net warming the planet.

Theoretical analysis and experimental investigation on performance of the thermal shield of accelerator cryomodules by thermo-siphon cooling of liquid nitrogen

NASA Astrophysics Data System (ADS)

Datta, T. S.; Kar, S.; Kumar, M.; Choudhury, A.; Chacko, J.; Antony, J.; Babu, S.; Sahu, S. K.

2015-12-01

Five beam line cryomodules with total 27 superconducting Radio Frequency (RF) cavities are installed and commissioned at IUAC to enhance the energy of heavy ion from 15 UD Pelletron. To reduce the heat load at 4.2 K, liquid nitrogen (LN2) cooled intermediate thermal shield is used for all these cryomodules. For three linac cryomodules, concept of forced flow LN2 cooling is used and for superbuncher and rebuncher, thermo-siphon cooling is incorporated. It is noticed that the shield temperature of superbuncher varies from 90 K to 110 K with respect to liquid nitrogen level. The temperature difference can't be explained by using the basic concept of thermo-siphon with the heat load on up flow line. A simple thermo-siphon experimental set up is developed to simulate the thermal shield temperature profile. Mass flow rate of liquid nitrogen is measured with different heat load on up flow line for different liquid levels. It is noticed that small amount of heat load on down flow line have a significant effect on mass flow rate. The present paper will be investigating the data generated from the thermosiphon experimental set up and a theoretical analysis will be presented here to validate the measured temperature profile of the cryomodule shield.

Control of hydrocarbon emissions from gasoline loading by refrigeration systems. Final report Dec 80-Apr 81

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

Battye, W.; Brown, P.; Misenheimer, D.

1981-07-01

The report gives results of a study of the capabilities of refrigeration systems, operated at three temperatures, to control volatile organic compound (VOC) emissions from truck loading at bulk gasoline terminals. Achievable VOC emission rates were calculated for refrigeration systems cooling various gasoline/air mixtures to -62 C, -73 C, and -84 C by estimating vapor/liquid equilibrium compositions for VOC/air mixtures. Emission rates were calculated for inlet streams containing vapors from low- and high-volatility gasolines at concentrations of 15, 30, and 50% by volume (22.5, 45, and 75% measured as propane). Predicted VOC emission rates for systems cooling various inlet streamsmore » to -62 C ranged from 48 to 59 mg VOC/liter of gasoline loaded. Predicted VOC were 21 to 28 mg/l loaded for systems operating at -73 C and 8.7 to 12 mg/l loaded for systems operating at -84 C. Compressor electrical requirements and relative capital costs for systems operating at the above temperatures were estimated for model systems using the results of a computer simulation. Compressor electrical requirements ranged from 0.11 to 0.45 Whr/l loaded, depending on the inlet VOC concentration and the outlet temperature. The capital cost to build a system designed to cool vapors to -84 C is estimated to be about 9% higher than for a system designed to operate at -73 C.« less

Reduced cooling following future volcanic eruptions

NASA Astrophysics Data System (ADS)

Hopcroft, Peter O.; Kandlbauer, Jessy; Valdes, Paul J.; Sparks, R. Stephen J.

2017-11-01

Volcanic eruptions are an important influence on decadal to centennial climate variability. Large eruptions lead to the formation of a stratospheric sulphate aerosol layer which can cause short-term global cooling. This response is modulated by feedback processes in the earth system, but the influence from future warming has not been assessed before. Using earth system model simulations we find that the eruption-induced cooling is significantly weaker in the future state. This is predominantly due to an increase in planetary albedo caused by increased tropospheric aerosol loading with a contribution from associated changes in cloud properties. The increased albedo of the troposphere reduces the effective volcanic aerosol radiative forcing. Reduced sea-ice coverage and hence feedbacks also contribute over high-latitudes, and an enhanced winter warming signal emerges in the future eruption ensemble. These findings show that the eruption response is a complex function of the environmental conditions, which has implications for the role of eruptions in climate variability in the future and potentially in the past.

Scalable loading of a two-dimensional trapped-ion array

PubMed Central

Bruzewicz, Colin D.; McConnell, Robert; Chiaverini, John; Sage, Jeremy M.

2016-01-01

Two-dimensional arrays of trapped-ion qubits are attractive platforms for scalable quantum information processing. Sufficiently rapid reloading capable of sustaining a large array, however, remains a significant challenge. Here with the use of a continuous flux of pre-cooled neutral atoms from a remotely located source, we achieve fast loading of a single ion per site while maintaining long trap lifetimes and without disturbing the coherence of an ion quantum bit in an adjacent site. This demonstration satisfies all major criteria necessary for loading and reloading extensive two-dimensional arrays, as will be required for large-scale quantum information processing. Moreover, the already high loading rate can be increased by loading ions in parallel with only a concomitant increase in photo-ionization laser power and no need for additional atomic flux. PMID:27677357

Low-Load Space Conditioning Needs Assessment

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

Puttagunta, Srikanth

Heating, ventilating, and air-conditioning (HVAC) equipment must be right-sized to ensure energy performance and comfort. With limited low-load options in the HVAC market, many new-construction housing units are being fitted with oversized equipment that creates system efficiency, comfort, and cost penalties. To bridge the gap between currently available HVAC equipment that is oversized or inefficient and the rising demand for low-load HVAC equipment in the marketplace, HVAC equipment manufacturers need to be fully aware of the needs of the multifamily building and attached single-family (duplex and townhouse) home market. Over the past decade, Steven Winter Associates, Inc. (SWA) has providedmore » certification and consulting services for hundreds of housing projects and has accrued a large pool of data that describe multifamily and attached single-family home characteristics. The U.S. Department of Energy’s Building America research team Consortium for Advanced Residential Buildings (CARB) compiled and analyzed these data to outline the characteristics of low-load dwellings such as the heating and cooling design loads.« less

The effect of alcohol blends on the performance of an air cooled Rotary Trochoidal Engine

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

Gutman, M.; Iuster, I.

Results obtained from tests on an air cooled Rotary Trochoidal Engine fueled with a gasoline-alcohol mixture, without modification of the carburetor, are presented in this paper. The tests were performed with one and two spark plugs. Amongst the obtained results, lower thermal load, better economy and improvement in cycling uniformity when running with two spark plugs were observed. The observed reduction in the rotor housing wall temperature and in the oil sump temperature presents particular advantages for an air cooled engine.

The effect of alcohol blends on the performance of an air cooled rotary trochoidal engine

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

Gutman, M.; Iuster, I.

Results obtained from tests on an air cooled Rotary Trochoidal Engine fueled with a gasoline-alcohol mixture, without modification of the carburetor, are presented in this paper. The tests were performed with one and two spark plugs. Amongst the obtained results, lower thermal load, better economy and improvement in cycling uniformity when running with two spark plugs were observed. The observed reduction in the rotor housing wall temperature and in the oil sump temperature presents particular advantages for an air cooled engine.

Modelling future impacts of air pollution using the multi-scale UK Integrated Assessment Model (UKIAM).

PubMed

Oxley, Tim; Dore, Anthony J; ApSimon, Helen; Hall, Jane; Kryza, Maciej

2013-11-01

Integrated assessment modelling has evolved to support policy development in relation to air pollutants and greenhouse gases by providing integrated simulation tools able to produce quick and realistic representations of emission scenarios and their environmental impacts without the need to re-run complex atmospheric dispersion models. The UK Integrated Assessment Model (UKIAM) has been developed to investigate strategies for reducing UK emissions by bringing together information on projected UK emissions of SO2, NOx, NH3, PM10 and PM2.5, atmospheric dispersion, criteria for protection of ecosystems, urban air quality and human health, and data on potential abatement measures to reduce emissions, which may subsequently be linked to associated analyses of costs and benefits. We describe the multi-scale model structure ranging from continental to roadside, UK emission sources, atmospheric dispersion of emissions, implementation of abatement measures, integration with European-scale modelling, and environmental impacts. The model generates outputs from a national perspective which are used to evaluate alternative strategies in relation to emissions, deposition patterns, air quality metrics and ecosystem critical load exceedance. We present a selection of scenarios in relation to the 2020 Business-As-Usual projections and identify potential further reductions beyond those currently being planned. © 2013.

Comparative study of control strategies for hybrid GSHP system in the cooling dominated climate

DOE PAGES

Wang, Shaojie; Liu, Xiaobing; Gates, Steve

2015-01-06

The ground source heat pump (GSHP) system is one of the most energy efficient HVAC technologies in the current market. However, the heat imbalance may degrade the ability of the ground loop heat exchanger (GLHX) to absorb or reject heat. The hybrid GSHP system, which combines a geothermal well field with a supplemental boiler or cooling tower, can balance the loads imposed on the ground loop heat exchangers to minimize its size while retaining superior energy efficiency. This paper presents a recent simulation-based study with an intention to compare multiple common control strategies used in hybrid GSHP systems, including fixedmore » setpoint, outside air reset, load reset, and wetbulb reset. A small office in Oklahoma City conditioned by a hybrid GSHP system was simulated with the latest version of eQUEST 3.7 [1]. In the end, the simulation results reveal that the hybrid GSHP system has the excellent capability to meet the cooling and heating setpoints during the occupied hours, balance thermal loads on the ground loop, as well as improve the thermal comfort of the occupants with the reduced size well field.« less

Micro-environmental control for efficient local cooling

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

Kong, Meng; Dang, Thong Q.; Zhang, Jianshun

Micro-environment is hereby defined as the air space and environment around a person that directly impacts his/her thermal sensation. Most existing HVAC systems condition the air of the entire room including the unoccupied space, which leaves a big potential to save energy. This study aims at evaluating the performance of three existing air terminal devices (ATDs) to locally remove enough heat from the micro-environment to manage the thermal balance so as not to sacrifice thermal comfort when the ambient unoccupied space temperature is increased by 2.2 °C from 23.9 °C to 26.1 °C in the summer to reduce the externalmore » cooling load. A computational fluid dynamics (CFD) model was developed, validated by full-scale chamber tests and applied to evaluate different configurations of the ATDs for local cooling. Results show that the predicted performance agreed well with the measurements, and the selected ATD, with only 50 W cooling power, was always able to remove a sufficient amount of heat from the microenvironment in a room of raised temperature, when the manikin was moved inside a semicircle movement range. The cooling performance of the jet was increased more by increasing the supply air flow rate than reducing the supply temperature and was highly dependent on the shooting angle. Finally, the heat flux from the manikin surface is very sensitive to the surface temperature and furniture placement, and proper specification of the surface temperature is crucial for the CFD simulation to match the measured results.« less

Micro-environmental control for efficient local cooling

DOE PAGES

Kong, Meng; Dang, Thong Q.; Zhang, Jianshun; ...

2017-06-01

Micro-environment is hereby defined as the air space and environment around a person that directly impacts his/her thermal sensation. Most existing HVAC systems condition the air of the entire room including the unoccupied space, which leaves a big potential to save energy. This study aims at evaluating the performance of three existing air terminal devices (ATDs) to locally remove enough heat from the micro-environment to manage the thermal balance so as not to sacrifice thermal comfort when the ambient unoccupied space temperature is increased by 2.2 °C from 23.9 °C to 26.1 °C in the summer to reduce the externalmore » cooling load. A computational fluid dynamics (CFD) model was developed, validated by full-scale chamber tests and applied to evaluate different configurations of the ATDs for local cooling. Results show that the predicted performance agreed well with the measurements, and the selected ATD, with only 50 W cooling power, was always able to remove a sufficient amount of heat from the microenvironment in a room of raised temperature, when the manikin was moved inside a semicircle movement range. The cooling performance of the jet was increased more by increasing the supply air flow rate than reducing the supply temperature and was highly dependent on the shooting angle. Finally, the heat flux from the manikin surface is very sensitive to the surface temperature and furniture placement, and proper specification of the surface temperature is crucial for the CFD simulation to match the measured results.« less

Heat pipe cooling system with sensible heat sink

NASA Technical Reports Server (NTRS)

Silverstein, Calvin C.

1988-01-01

A heat pipe cooling system which employs a sensible heat sink is discussed. With this type of system, incident aerodynamic heat is transported via a heat pipe from the stagnation region to the heat sink and absorbed by raising the temperature of the heat sink material. The use of a sensible heat sink can be advantageous for situations where the total mission heat load is limited, as it is during re-entry, and a suitable radiation sink is not available.

Design Evaluation Using Finite Element Analysis of Cooled Silicon Nitride Plates for a Turbine Blade Application

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Baaklini, George Y.; Bhatt, Ramakrishna T.

2001-01-01

Two- and three-dimensional finite element analyses were performed on uncoated and thermal barrier coated (TBC) silicon nitride plates with and without internal cooling by air. Steady-state heat-transfer analyses were done to optimize the size and the geometry of the cooling channels to reduce thermal stresses, and to evaluate the thermal environment experienced by the plate during burner rig testing. The limited experimental data available were used to model the thermal profile exerted by the flame on the plate. Thermal stress analyses were performed to assess the stress response due to thermal loading. Contours for the temperature and the representative stresses for the plates were generated and presented for different cooling hole sizes and shapes. Analysis indicates that the TBC experienced higher stresses, and the temperature gradient was much reduced when the plate was internally cooled by air. The advantages and disadvantages of several cooling channel layouts were evaluated.

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

Calder Hall Cooling Tower Demolition: Landmark Milestone for Decommissioning at Sellafield

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

Williamson, E.J.

2008-07-01

September 2007 saw a very visible change to the Sellafield site following the culmination of a major decommissioning project; the demolition of the four Calder Hall cooling towers. A key part of the UK's nuclear industrial heritage, Calder Hall, the world's first commercial nuclear power station, was opened by Her Majesty Queen Elizabeth II in October 1953 and continued to generate electricity until its closure in 2003. Following the decision to decommission the Calder Hall site, explosive demolition was identified as the safest and most cost effective route for the removal of the towers. The technique, involving the placement ofmore » explosive in 60% of the circumference of both shell and legs, is a tried and tested method which had already been used successfully in more than 200 cooling towers in the UK in the last 30 years. The location and composition of the four 88 metre high towers also created additional challenges. Situated only 40 metres away from the UK's only nuclear Fuel Handling Plant, as well as other sensitive structures on the Sellafield site, the project had to address the impact of a number of key areas, including dust, ground vibration and air over pressure, to ensure that the demolition could be carried out safely and without significant impact on other operational areas on the site. At the same time, the towers had to be prepared for demolition in a way that minimised the amounts of radioactive or hazardous waste materials arising. This paper follows the four year journey from the initial decision to demolish the towers right through to the demolition itself as well as the clean up of the site post demolition. It will also consider the massive programme of work necessary not only to carry out the physical work safely but also to gain regulatory confidence and stakeholder support to carry out the project successfully. In summary: The demolition of the four Calder Hall cooling towers was a highly visible symbol of the changes that are

The experimental program for high pressure gas filled radio frequency cavities for muon cooling channels

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

Freemire, B.; Chung, M.; Hanlet, P. M.

An intense beam of muons is needed to provide a luminosity on the order of 10 34 cm -2s -1 for a multi-TeV collider. Because muons produced by colliding a multi-MW proton beam with a target made of carbon or mercury have a large phase space, significant six dimensional cooling is required. Through ionization cooling—the only cooling method that works within the lifetime of the muon—and emittance exchange, the desired emittances for a Higgs Factory or higher energy collider are attainable. A cooling channel utilizing gas filled radio frequency cavities has been designed to deliver the requisite cool muon beam.more » Technology development of these RF cavities has progressed from breakdown studies, through beam tests, to dielectric loaded and reentrant cavity designs. The results of these experiments are summarized.« less

The experimental program for high pressure gas filled radio frequency cavities for muon cooling channels

DOE PAGES

Freemire, B.; Chung, M.; Hanlet, P. M.; ...

2018-01-30

An intense beam of muons is needed to provide a luminosity on the order of 10 34 cm -2s -1 for a multi-TeV collider. Because muons produced by colliding a multi-MW proton beam with a target made of carbon or mercury have a large phase space, significant six dimensional cooling is required. Through ionization cooling—the only cooling method that works within the lifetime of the muon—and emittance exchange, the desired emittances for a Higgs Factory or higher energy collider are attainable. A cooling channel utilizing gas filled radio frequency cavities has been designed to deliver the requisite cool muon beam.more » Technology development of these RF cavities has progressed from breakdown studies, through beam tests, to dielectric loaded and reentrant cavity designs. The results of these experiments are summarized.« less

Small Spacecraft Active Thermal Control: Micro-Vascular Composites Enable Small Satellite Cooling

NASA Technical Reports Server (NTRS)

Ghosh, Alexander

2016-01-01

The Small Spacecraft Integrated Power System with Active Thermal Control project endeavors to achieve active thermal control for small spacecraft in a practical and lightweight structure by circulating a coolant through embedded micro-vascular channels in deployable composite panels. Typically, small spacecraft rely on small body mounted passive radiators to discard heat. This limits cooling capacity and leads to the necessity to design for limited mission operations. These restrictions severely limit the ability of the system to dissipate large amounts of heat from radios, propulsion systems, etc. An actively pumped cooling system combined with a large deployable radiator brings two key advantages over the state of the art for small spacecraft: capacity and flexibility. The use of a large deployable radiator increases the surface area of the spacecraft and allows the radiation surface to be pointed in a direction allowing the most cooling, drastically increasing cooling capacity. With active coolant circulation, throttling of the coolant flow can enable high heat transfer rates during periods of increased heat load, or isolate the radiator during periods of low heat dissipation.

Simulation of a 20-ton LiBr/H{sub 2}O absorption cooling system

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

Wardono, B.; Nelson, R.M.

The possibility of using solar energy as the main heat input for cooling systems has led to several studies of available cooling technologies that use solar energy. The results show that double-effect absorption cooling systems give relatively high performance. To further study absorption cooling systems, a computer code was developed for a double-effect lithium bromide/water (LiBr/H{sub 2}O) absorption system. To evaluate the performance, two objective functions were developed including the coefficient of performance (COP) and the system cost. Based on the system cost, an optimization to find the minimum cost was performed to determine the nominal heat transfer areas ofmore » each heat exchanger. The nominal values of other system variables, such as the mass flow rates and inlet temperatures of the hot water, cooling water, and chilled water, are specified as commonly used values for commercial machines. The results of the optimization show that there are optimum heat transfer areas. In this study, hot water is used as the main energy input. Using a constant load of 20 tons cooling capacity, the effects of various variables including the heat transfer ares, mass flow rates, and inlet temperatures of hot water, cooling water, and chilled water are presented.« less

Sustained Load Crack Growth in Inconel 718 Under Non-Isothermal Conditions.

DTIC Science & Technology

1983-12-01

AD- R136 925 SUSTINED LOAD CRCK GROWTH IN INCONEL 7±8 UNDER / NON-ISOTHERM L ONDITIONS(U) IR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF...thermocouples. This unit provides pre-programmed independent control of the four heat- Iing lamps. It also turns the cooling system on and off at the appropri...relationship between them. The microcomputer controls temperature as a function of time. The system is capable of heating and cooling a specimen at a rate of 8C

Design and implementation of a multiaxial loading capability during heating on an engineering neutron diffractometer.

PubMed

Benafan, O; Padula, S A; Skorpenske, H D; An, K; Vaidyanathan, R

2014-10-01

A gripping capability was designed, implemented, and tested for in situ neutron diffraction measurements during multiaxial loading and heating on the VULCAN engineering materials diffractometer at the spallation neutron source at Oak Ridge National Laboratory. The proposed capability allowed for the acquisition of neutron spectra during tension, compression, torsion, and/or complex loading paths at elevated temperatures. The design consisted of age-hardened, Inconel(®) 718 grips with direct attachment to the existing MTS load frame having axial and torsional capacities of 100 kN and 400 N·m, respectively. Internal cooling passages were incorporated into the gripping system for fast cooling rates during high temperature experiments up to ∼1000 K. The specimen mounting couplers combined a threaded and hexed end-connection for ease of sample installation/removal without introducing any unwanted loads. Instrumentation of this capability is documented in this work along with various performance parameters. The gripping system was utilized to investigate deformation in NiTi shape memory alloys under various loading/control modes (e.g., isothermal, isobaric, and cyclic), and preliminary results are presented. The measurements facilitated the quantification of the texture, internal strain, and phase fraction evolution in NiTi shape memory alloys under various loading/control modes.

Design and implementation of a multiaxial loading capability during heating on an engineering neutron diffractometer

NASA Astrophysics Data System (ADS)

Benafan, O.; Padula, S. A.; Skorpenske, H. D.; An, K.; Vaidyanathan, R.

2014-10-01

A gripping capability was designed, implemented, and tested for in situ neutron diffraction measurements during multiaxial loading and heating on the VULCAN engineering materials diffractometer at the spallation neutron source at Oak Ridge National Laboratory. The proposed capability allowed for the acquisition of neutron spectra during tension, compression, torsion, and/or complex loading paths at elevated temperatures. The design consisted of age-hardened, Inconel® 718 grips with direct attachment to the existing MTS load frame having axial and torsional capacities of 100 kN and 400 N.m, respectively. Internal cooling passages were incorporated into the gripping system for fast cooling rates during high temperature experiments up to ˜1000 K. The specimen mounting couplers combined a threaded and hexed end-connection for ease of sample installation/removal without introducing any unwanted loads. Instrumentation of this capability is documented in this work along with various performance parameters. The gripping system was utilized to investigate deformation in NiTi shape memory alloys under various loading/control modes (e.g., isothermal, isobaric, and cyclic), and preliminary results are presented. The measurements facilitated the quantification of the texture, internal strain, and phase fraction evolution in NiTi shape memory alloys under various loading/control modes.

Experimental evaluation of an adaptive Joule–Thomson cooling system including silicon-microfabricated heat exchanger and microvalve components

PubMed Central

Zhu, Weibin; Park, Jong M.; White, Michael J.; Nellis, Gregory F.; Gianchandani, Yogesh B.

2011-01-01

This article reports the evaluation of a Joule–Thomson (JT) cooling system that combines two custom micromachined components—a Si/glass-stack recuperative heat exchanger and a piezoelectrically actuated expansion microvalve. With the microvalve controlling the flow rate, this system can modulate cooling to accommodate varying refrigeration loads. The perforated plate Si/glass heat exchanger is fabricated with a stack of alternating silicon plates and Pyrex glass spacers. The microvalve utilizes a lead zirconate titanate actuator to push a Si micromachined valve seat against a glass plate, thus modulating the flow passing through the gap between the valve seat and the glass plate. The fabricated heat exchanger has a footprint of 1×1 cm2 and a length of 35 mm. The size of the micromachined piezoelectrically actuated valve is about 1×1×1 cm3. In JT cooling tests, the temperature of the system was successfully controlled by adjusting the input voltage of the microvalve. When the valve was fully opened (at an input voltage of −30 V), the system cooled down to a temperature as low as 254.5 K at 430 kPa pressure difference between inlet and outlet at steady state and 234 K at 710 kPa in a transient state. The system provided cooling powers of 75 mW at 255 K and 150 mW at 258 K. Parasitic heat loads at 255 K are estimated at approximately 700 mW. PMID:21552354

Cooling Flows

NASA Astrophysics Data System (ADS)

Fabian, A.; Murdin, P.

2000-11-01

A subsonic cooling flow occurs when the hot gaseous atmosphere of a galaxy, group or cluster of galaxies cools slowly. Such atmospheres occur as a result of gas having fallen into the DARK MATTER well of the object and heated by gravitational energy release. A dominant cooling process is the emission of radiation by the gas. As cooling proceeds the gas sinks further in the potential well, giving ...

Analytical and experimental studies of heat pipe radiation cooling of hypersonic propulsion systems

NASA Technical Reports Server (NTRS)

Martin, R. A.; Merrigan, M. A.; Elder, M. G.; Sena, J. T.; Keddy, E. S.; Silverstein, C. C.

1992-01-01

Analytical and experimental studies were completed to assess the feasibility of using high-temperature heat pipes to cool hypersonic engine components. This new approach involves using heat pipes to transport heat away from the combustor, nozzle, or inlet regions, and to reject it to the environment by thermal radiation from an external heat pipe nacelle. For propulsion systems using heat pipe radiation cooling (HPRC), it is possible to continue to use hydrocarbon fuels into the Mach 4 to Mach 6 speed range, thereby enhancing the economic attractiveness of commercial or military hypersonic flight. In the second-phase feasibility program recently completed, it is found that heat loads produced by considering both convection and radiation heat transfer from the combustion gas can be handled with HPRC design modifications. The application of thermal insulation to ramburner and nozzle walls was also found to reduce the heat load by about one-half and to reduce peak HPRC system temperatures to below 2700 F. In addition, the operation of HPRC at cruise conditions of around Mach 4.5 and at an altitude of 90,000 ft lowers the peak hot-section temperatures to around 2800 F. An HPRC heat pipe was successfully fabricated and tested at Mach 5 conditions of heat flux, heat load, and temperature.

Design and Test of Wendelstein 7-X Water-Cooled Divertor Scraper

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

Boscary, J.; Greuner, Henri; Ehrke, Gunnar

Heat load calculations have indicated the possible overloading of the ends of the water-cooled divertor facing the pumping gap beyond their technological limit. The intention of the scraper is the interception of some of the plasma fluxes both upstream and downstream before they reach the divertor surface. The scraper is divided into six modules of four plasma facing components (PFCs); each module has four PFCs hydraulically connected in series by two water boxes (inlet and outlet). A full-scale prototype of one module has been manufactured. Development activities have been carried out to connect the water boxes to the cooling pipesmore » of the PFCs by tungsten inert gas internal orbital welding. This prototype was successfully tested in the GLADIS facility with 17 MW/m2 for 500 cycles. The results of these activities have confirmed the possible technological basis for a fabrication of the water-cooled scraper.« less

Report on Lincoln Electric System gas turbine inlet air cooling. Final report

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

Ebeling, J.A.; Buecker, B.J.; Kitchen, B.J.

1993-12-01

As a result of increased electric power demand, the Lincoln Electric System (LES) of Lincoln, Nebraska (USA) decided to upgrade the generating capacity of their system. Based on capacity addition studies, the utility elected to improve performance of a GE MS7001B combustion turbine located at their Rokeby station. The turbine is used to meet summer-time peak loads, and as is common among combustion turbines, capacity declines as ambient air temperature rises. To improve the turbine capacity, LES decided to employ the proven technique of inlet air cooling, but with a novel approach: off-peak ice generation to be used for peak-loadmore » air cooling. EPRI contributed design concept definition and preliminary engineering. The American Public Power Association provided co-funding. Burns & McDonnell Engineering Company, under contract to Lincoln Electric System, provided detailed design and construction documents. LES managed the construction, start-up, and testing of the cooling system. This report describes the technical basis for the cooling system design, and it discusses combustion turbine performance, project economics, and potential system improvements. Control logic and P&ID drawings are also included. The inlet air cooling system has been available since the fall of 1991. When in use, the cooling system has increased turbine capacity by up to 17% at a cost of less than $200 per increased kilowatt of generation.« less

Cooling for SC devices of test cryomodule for ADS Injector II at IMP

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

Wang, L.; Wang, S. Y.; Sun, S.

2014-01-29

The superconducting half-wave resonance cavities connected in series with superconducting solenoids will be applied to the Injector II of the Accelerator Driven Sub-critical System (ADS) to be built at the Modern Physics Institute, China. A test system has been developed for the purpose of performance test of the HWR cavities as well as validating the relevant technique for cooling the cavity and the solenoids together. It mainly comprises a cryogenic valve box (TVB), a test cryomodule (TCM1) and transfer lines. The TCM1 includes one HWR cavity, two superconducting solenoids, one cold BPM and their cooling system. The design of themore » TCM1 cryostat was carried out by the Shanghai Institute of Applied Physics (SINAP), CAS. Both the cavity and the solenoids will work at 4.4 K by bath cooling. The fast cooling down for the cavity from around 100 K to 120 K is required to avoid degrading of the cavity performance. After cool down and before energization, the solenoids should be warmed up to above 10 K and re-cooled down for the purpose of degaussing. The TCM1 can not only be cooled by using the dewar-filling system, but also operated by the refrigerator system. For the purpose of reducing the heat loads to the cold mass at 4 K from room temperature, thermal radiation shields cooled by liquid nitrogen flowing in tubing were employed. This paper presents the design details of cooling circuits and thermal shields of the TCM1 as well as related calculations and analyses.« less

Cooling for SC devices of test cryomodule for ADS Injector II at IMP

NASA Astrophysics Data System (ADS)

Wang, L.; Wang, S. Y.; Sun, S.; Guo, X. L.; Wang, S. H.; Liu, Y. Y.

2014-01-01

The superconducting half-wave resonance cavities connected in series with superconducting solenoids will be applied to the Injector II of the Accelerator Driven Sub-critical System (ADS) to be built at the Modern Physics Institute, China. A test system has been developed for the purpose of performance test of the HWR cavities as well as validating the relevant technique for cooling the cavity and the solenoids together. It mainly comprises a cryogenic valve box (TVB), a test cryomodule (TCM1) and transfer lines. The TCM1 includes one HWR cavity, two superconducting solenoids, one cold BPM and their cooling system. The design of the TCM1 cryostat was carried out by the Shanghai Institute of Applied Physics (SINAP), CAS. Both the cavity and the solenoids will work at 4.4 K by bath cooling. The fast cooling down for the cavity from around 100 K to 120 K is required to avoid degrading of the cavity performance. After cool down and before energization, the solenoids should be warmed up to above 10 K and re-cooled down for the purpose of degaussing. The TCM1 can not only be cooled by using the dewar-filling system, but also operated by the refrigerator system. For the purpose of reducing the heat loads to the cold mass at 4 K from room temperature, thermal radiation shields cooled by liquid nitrogen flowing in tubing were employed. This paper presents the design details of cooling circuits and thermal shields of the TCM1 as well as related calculations and analyses.

Continuous Cooling from 10 K to 4 K Using a Toroidal ADR

NASA Technical Reports Server (NTRS)

DiPirro, Michael J.; Canavan, Edgar R.; Shirron, Peter J.; Tuttle, James G.

2003-01-01

Future large infrared space telescopes will require cooling to 4K to achieve background limited performance for submillimeter wavelengths. These observatories will require lifetimes of many years and will have relatively large cooling requirements making stored helium dewars impractical. We have designed and are building an adiabatic demagnetization refrigerator (ADR) for use in cooling relatively large loads (10- 100 mW) at 4K and rejecting that heat to a cryocooler operating at 1 OK. Cryocoolers below 1 OK have poor thermodynamic efficiency and ADRs can operate in this temperature range with an efficiency of 75% of Carnot or better. Overall, this can save as much as 2/3 of the input power required to operate a 4K cryocooler. The ADR magnet consists of 8 short coils wired in series and arranged in a toroid to provide self shielding of its magnetic field. This will save mass (about 30% of the mass or about 1.5 kg in our small version, higher percentages in higher cooling power, larger versions) that would have been used for passive or active shields in an ordinary solenoid. The toroid has a 100 mm outer diameter and will produce an approximately 3T average field. In the initial demonstration model the toroid coils will be wound with ordinary NbTi wire and operated at 4K. A second version will then use Nb3Sn wire to provide complete 10K operation. As a refrigerant for this temperature range we will use either GdLiF4 or GdF3 crystals, pending tests of these crystals' cooling capacity per field and thermal conductance. Preliminary indications are that these materials are superior to GGG. We will use gas gap heat switches to alternately connect the toroid to the cold load and the warm heat sink. A small continuous stage will maintain the cold end at 4K while the main toroid is recycled.

Development and fabrication of an advanced liquid cooling garment

NASA Technical Reports Server (NTRS)

Leith, J. R.; Hixon, C. W.

1976-01-01

The elastomeric film fin/tube concept which was developed is a composite of polyurethane film, fine expanded silver mesh, a serpentine pattern polyurethane transport tubing and an integral comfort liner, all bonded via adhesive application and vacuum-bagged for final cure. As demonstrated by thermal analysis, the composite garment material is capable of removing a 293 watt (1000 BTU/hr) metabolic load through a head and torso cooling area of .46 sq m (5 sq ft) with tube spacing of slightly under one inch. A total of 60 test elements, each .15m x .15m (6 in. x 6 in.) were fabricated in support of the liquid cooling garment concept development. In parallel with the fabrication of these elements a continuing series of laboratory tests to support the fabrication techniques was carried out. The elements and supporting tests are described.

Development of a thermal and structural analysis procedure for cooled radial turbines

NASA Technical Reports Server (NTRS)

Kumar, Ganesh N.; Deanna, Russell G.

1988-01-01

A procedure for computing the rotor temperature and stress distributions in a cooled radial turbine is considered. Existing codes for modeling the external mainstream flow and the internal cooling flow are used to compute boundary conditions for the heat transfer and stress analyses. An inviscid, quasi three-dimensional code computes the external free stream velocity. The external velocity is then used in a boundary layer analysis to compute the external heat transfer coefficients. Coolant temperatures are computed by a viscous one-dimensional internal flow code for the momentum and energy equation. These boundary conditions are input to a three-dimensional heat conduction code for calculation of rotor temperatures. The rotor stress distribution may be determined for the given thermal, pressure and centrifugal loading. The procedure is applied to a cooled radial turbine which will be tested at the NASA Lewis Research Center. Representative results from this case are included.

Development of a thermal and structural analysis procedure for cooled radial turbines

NASA Technical Reports Server (NTRS)

Kumar, Ganesh N.; Deanna, Russell G.

1988-01-01

A procedure for computing the rotor temperature and stress distributions in a cooled radial turbine are considered. Existing codes for modeling the external mainstream flow and the internal cooling flow are used to compute boundary conditions for the heat transfer and stress analysis. The inviscid, quasi three dimensional code computes the external free stream velocity. The external velocity is then used in a boundary layer analysis to compute the external heat transfer coefficients. Coolant temperatures are computed by a viscous three dimensional internal flow cade for the momentum and energy equation. These boundary conditions are input to a three dimensional heat conduction code for the calculation of rotor temperatures. The rotor stress distribution may be determined for the given thermal, pressure and centrifugal loading. The procedure is applied to a cooled radial turbine which will be tested at the NASA Lewis Research Center. Representative results are given.

Carbon loading of alveolar macrophages in adults and children exposed to biomass smoke particles.

PubMed

Kulkarni, Neeta S; Prudon, Benjamin; Panditi, Sri L; Abebe, Yekoye; Grigg, Jonathan

2005-06-01

Exposure to carbonaceous particles from biomass burning is associated with increased respiratory morbidity in both women and children in the developing world. However, the amount of carbon reaching lower airway cells has not been determined in these populations. Alveolar macrophages (AM) remove inhaled particulate matter (PM), and are implicated in the pathogenesis of PM-induced lung disease. In this study, we aimed to compare AM carbon loading in women and children exposed to biomass PM in Gondar, Ethiopia, with individuals exposed to fossil-fuel PM in the developed world (Leicester, UK). To achieve these aims, we sampled AM from Ethiopian mothers and children, and from UK adults and children using induced sputum (IS). AM were imaged under light microscopy, and the total two-dimensional surface area of carbon within each AM determined by image analysis. AM containing carbon were detected in all subjects. The total surface area of carbon per AM was higher in Ethiopian women (n=10) compared with UK adults (n=10, median 9.19 vs. 0.71 microm2/AM, p=0.0002). Similarly, the total surface area of carbon per AM was higher in Ethiopian children (n=10) compared with UK children (n=10, 3.32 vs. 0.44 microm2/AM, p=0.0002). However, loading in Ethiopian children was lower than paired maternal levels (3.32 vs. 9.19 microm2/AM, p=0.011). We conclude that analysis of AM obtained by induced sputum is a practical way of quantifying natural exposure of the lower airway to carbonaceous particles from the burning of biomass fuels.

An Hybrid liquid nitrogen system to cool a large detector

NASA Astrophysics Data System (ADS)

l'Allemand, J. L. Lizon a.

2017-12-01

OmegaCAM is a wide field camera housing a mosaic of 32 CCD detectors. For the optimal trade-off between dark current, sensitivity, and cosmetics, these detectors need to be operated at a temperature of about 155 K. The detectors mosaic with a total area of 630 cm2 directly facing the Dewar entrance window, is exposed to a considerable radiation heat load. This can only be achieved with a high-performing cooling system. In addition this system has to be operated at the moving focal plane of a telescope. The paper describes the cooling system, which is build such that it makes the most efficient use of the cooling power of the liquid nitrogen. This is obtained by forcing the nitrogen through a series of well designed and strategically distributed heat exchangers. Results and performance of the system recorded during the laboratory system testing are reported as well. In addition to the cryogenic performance, the document reports also about the overall performance of the instrument including long term vacuum behavior.

Have women born outside the U.K. driven the rise in U.K. births since 2001?

PubMed

Tromans, Nicola; Natamba, Eva; Jefferie, Julie

2009-01-01

The number of births in the U.K. has increased each year since 2001. This article examines the demographic drivers underlying this rise, assessing the contribution of U.K. born and foreign born women. It brings together key information from across the U.K. to provide a coherent picture of childbearing trends among U.K. born and foreign born women since 2001. Geographical variations in the proportion of births to foreign born women are also explored at the local authority level.

Sterilization by Cooling in Isochoric Conditions: The Case of Escherichia coli

PubMed Central

Salinas-Almaguer, Samuel; Angulo-Sherman, Abril; Sierra-Valdez, Francisco Javier; Mercado-Uribe, Hilda

2015-01-01

High hydrostatic pressure (HHP) affects the structure, metabolism and survival of micro-organisms including bacteria. For this reason HHP is a promising treatment in the food industry. The aim of this work is to evaluate the effect of high pressure, under isochoric cooling conditions, on Escherichia coli, where such high pressure develops due to the fact water cannot expand. We combine survival curves obtained by spectrophotometry and images of atomic force microscopy in this study. Our results show that cooling at -20 and -30°C leads to a partial destruction of a Escherichia coli population. However, cooling at -15°C causes a total extermination of bacteria. This intriguing result is explained by the phase diagram of water. In the first case, the simultaneous formation of ice III and ice Ih crystals provides a safe environment for bacteria. In the second case (-15°C) Escherichia coli remains in a metastable and amorphous free-of-crystals liquid subjected to high pressure. Our work is the first experimental study carried out to inactivate Escherichia coli under isochoric cooling conditions. Unlike HHP, which is based on the application of an external load to augment the pressure, this technique only requires cooling. The method could be used for annihilation of other Escherichia coli strains and perhaps other micro-organisms. PMID:26480032

Numerical Investigations of the Influence of Unsteady Vane Trailing Edge Shock Wave on Film Cooling Effectiveness of Rotor Blade Leading Edge

NASA Astrophysics Data System (ADS)

Wang, Yufeng; Cai, Le; Wang, Songtao; Zhou, Xun

2018-04-01

Unsteady numerical simulations of a high-load transonic turbine stage have been carried out to study the influences of vane trailing edge outer-extending shockwave on rotor blade leading edge film cooling performance. The turbine stage used in this paper is composed of a vane section and a rotor one which are both near the root section of a transonic high-load turbine stage. The Mach number is 0.94 at vane outlet, and the relative Mach number is above 1.10 at rotor outlet. Various positions and oblique angles of film cooling holes were investigated in this research. Results show that the cooling efficiency on the blade surface of rotor near leading edge is significantly affected by vane trailing edge outer-extending shockwave in some cases. In the cases that film holes are close to leading edge, cooling performance suffers more from the sweeping vane trailing edge outer-extending shockwave. In addition, coolant flow ejected from oblique film holes is harder to separate from the blade surface of rotor, and can cover more blade area even under the effects of sweeping vane trailing edge shockwave. As a result, oblique film holes can provide better film cooling performance than vertical film holes do near the leading edge on turbine blade which is swept by shockwaves.

Optimizing X-ray mirror thermal performance using matched profile cooling

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

Zhang, Lin; Cocco, Daniele; Kelez, Nicholas

2015-08-07

To cover a large photon energy range, the length of an X-ray mirror is often longer than the beam footprint length for much of the applicable energy range. To limit thermal deformation of such a water-cooled X-ray mirror, a technique using side cooling with a cooled length shorter than the beam footprint length is proposed. This cooling length can be optimized by using finite-element analysis. For the Kirkpatrick–Baez (KB) mirrors at LCLS-II, the thermal deformation can be reduced by a factor of up to 30, compared with full-length cooling. Furthermore, a second, alternative technique, based on a similar principle ismore » presented: using a long, single-length cooling block on each side of the mirror and adding electric heaters between the cooling blocks and the mirror substrate. The electric heaters consist of a number of cells, located along the mirror length. The total effective length of the electric heater can then be adjusted by choosing which cells to energize, using electric power supplies. The residual height error can be minimized to 0.02 nm RMS by using optimal heater parameters (length and power density). Compared with a case without heaters, this residual height error is reduced by a factor of up to 45. The residual height error in the LCLS-II KB mirrors, due to free-electron laser beam heat load, can be reduced by a factor of ~11belowthe requirement. The proposed techniques are also effective in reducing thermal slope errors and are, therefore, applicable to white beam mirrors in synchrotron radiation beamlines.« less

Innovative UK Approaches to Acquisition Management

DTIC Science & Technology

2009-05-01

Financial and Operational Imperatives Size of UK armed forces UK Industry ? Political influence PFI / PPP Increased Scrutiny - NAO “ Commercialisation “ of the...acquisition KNOWLEDGE (EXPERIENCE – Lessons learned) KNOWLEDGE (Training) KNOWLEDGE ( Education ) OPTIMAL OPERATIONAL PERFORMANCE Operational Capability UK

Role and Determinants of Adherence to Off-loading in Diabetic Foot Ulcer Healing: A Prospective Investigation.

PubMed

Crews, Ryan T; Shen, Biing-Jiun; Campbell, Laura; Lamont, Peter J; Boulton, Andrew J M; Peyrot, Mark; Kirsner, Robert S; Vileikyte, Loretta

2016-08-01

Studies indicate that off-loading adherence is low in patients with diabetic foot ulcers (DFUs), which may subsequently delay healing. However, there is little empirical evidence for this relationship or the factors that influence adherence. This prospective, multicenter, international study of 79 (46 from the U.K. and 33 the U.S.) persons with type 2 diabetes and plantar DFUs assessed the association between off-loading adherence and DFU healing over a 6-week period. Additionally, potential demographic, disease, and psychological determinants of adherence were examined. DFUs were off-loaded with a removable device (77% a removable cast walker). Off-loading adherence was assessed objectively by activity monitors. Patient-reported measures included Hospital Anxiety and Depression Scale (HADS), Neuropathy and Foot Ulcer Quality of Life (NeuroQoL) instrument, and Revised Illness Perception Questionnaire (IPQ-R). Off-loading adherence was monitored for 35 ± 10 days, and devices were used during 59 ± 22% of subjects' activity. In multivariate analyses, smaller baseline DFU size, U.K. study site, and better off-loading adherence predicted smaller DFU size at 6 weeks (P < 0.05). Better off-loading adherence was, in turn, predicted by larger and more severe baseline DFUs, more severe neuropathy, and NeuroQoL foot pain (P < 0.05). In contrast, greater NeuroQoL postural instability predicted worse off-loading adherence (P < 0.001). HADS and IPQ-R measures were not significantly associated with off-loading adherence. Off-loading adherence is associated with the amount of DFU healing that occurs, while postural instability is a powerful predictor of nonadherence. Clinicians should take this neuropathic symptom into consideration when selecting an off-loading device, as off-loading-induced postural instability may further contribute to nonadherence. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is

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.

Effectiveness of Cool Roof Coatings with Ceramic Particles

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

Brehob, Ellen G; Desjarlais, Andre Omer; Atchley, Jerald Allen

2011-01-01

reducing the cooling load cost and not incurring a large heating penalty cost) and suggests solar reflectivity is the significant characteristic for selecting cool roof coatings.« less

Study of fail-safe abort system for an actively cooled hypersonic aircraft, volume 2

NASA Technical Reports Server (NTRS)

Peeples, M. E.; Herring, R. L.

1976-01-01

Conceptual designs of a fail-safe abort system for hydrogen fueled actively cooled high speed aircraft are examined. The fail-safe concept depends on basically three factors: (1) a reliable method of detecting a failure or malfunction in the active cooling system, (2) the optimization of abort trajectories which minimize the descent heat load to the aircraft, and (3) fail-safe thermostructural concepts to minimize both the weight and the maximum temperature the structure will reach during descent. These factors are examined and promising approaches are evaluated based on weight, reliability, ease of manufacture and cost.

High-Altitude Flight Cooling Investigation of a Radial Air-Cooled Engine

NASA Technical Reports Server (NTRS)

Manganiello, Eugene J; Valerino, Michael F; Bell, E Barton

1947-01-01

An investigation of the cooling of an 18-cylinder, twin-row, radial, air-cooled engine in a high-performance pursuit airplane has been conducted for variable engine and flight conditions at altitudes ranging from 5000 to 35,000 feet in order to provide a basis for predicting high-altitude cooling performance from sea-level or low altitude experimental results. The engine cooling data obtained were analyzed by the usual NACA cooling-correlation method wherein cylinder-head and cylinder-barrel temperatures are related to the pertinent engine and cooling-air variables. A theoretical analysis was made of the effect on engine cooling of the change of density of the cooling air across the engine (the compressibility effect), which becomes of increasing importance as altitude is increased. Good agreement was obtained between the results of the theoretical analysis and the experimental data.

Positron cooling of antiprotons: precursor of recombination

NASA Astrophysics Data System (ADS)

Tan, J. N.; Estrada, J.; Yesley, P.; Bowden, N.; Oxley, P.; Storry, C.; Wessels, M.; Tan, J.; Gabrielse, G.; Oelert, W.; Scheppers, G.; Gronzonka, D.; Sefsick, T.; Fermann, H.; Zmeskal, H.; Breunlich, W.; Kalinowsky, H.; Wesdorp, C.

2001-05-01

The quest for cold antihydrogen, interrupted with the shut-down of LEAR, resumed with the operation of the newest antiproton decelerator (AD) at CERN.[See G.Gabrielse,Adv. in AMO Physics,vol.45,pp.1-38(2001).] Antiprotons injected into the AD with 2.75 GeV of kinetic energy slow to 5.31 MeV before extraction into the ATRAP apparatus, built for antihydrogen recombination experiments. Antiprotons extracted from the AD and positrons emitted from a 112 mCi ^22Na source are simultaneously accumulated in the ultra-high vacuum and 6 T field of a prototype Penning trap incorporating a miniature rotatable electrode. Preloaded electrons are used to thermalize ~ 10^5 antiprotons with the LHe-cooled trap (4.2K). Over 10^6 positrons/hr can be loaded with a new mechanism involving Rydberg positronium. After accumulation, the positrons are moved through the rotatable electrode into close proximity with the antiprotons to study their interactions. We report the first observation of positron cooling of antiprotons in a nested trap configuration suited for three-body recombination and other mechanisms.

Transpiration-Cooled Spacecraft-Insulation-Repair Fasteners

NASA Technical Reports Server (NTRS)

Camarda, Charles J.; Pettit, Donald R.; Glass, David; Scotti, Stephen J.; Vaughn, Wallace Lee; Rawal, Suraj

2012-01-01

Transpiration-cooled fasteners are proposed that operate like an open-loop heat pipe (self-tapping screws, bolts, and spikes) for use in on-orbit repair of thermal- insulation of a space shuttle or other spacecraft. By limiting the temperature rise of such a fastener and of the adjacent repair material and thermal protection system, the transpiration cooling would contribute to the ability of the repair to retain its strength and integrity in the high-heat-flux, oxidizing environment of reentry into the atmosphere of the Earth. A typical fastener according to the proposal would include a hollow refractory-metal, refractory-composite, or ceramic screw or bolt, the central cavity of which would be occupied by a porous refractory- metal or ceramic plug that would act as both a reservoir and a wick for a transpirant liquid. The plug dimensions, the plug material, and the sizes of the pores would be chosen in conjunction with the transpirant liquid so that (1) capillary pumping could be relied upon to transport the liquid to the heated surface, where the liquid would be vaporized, and (2) the amount of liquid would suffice for protecting against the anticipated heat flux and integrated heat load.

Numerical analysis on cooling performance of counterflowing jet over aerodisked blunt body

NASA Astrophysics Data System (ADS)

Barzegar Gerdroodbary, M.

2014-09-01

This study investigates a combined technique of both an active flow control concept that uses counterflowing jets and an aerodisk spike as a new method to significantly modify external flowfields and heat reduction in a hypersonic flow around a nose cone. The coolant gas (Carbon Dioxide and Helium) is chosen to inject from the tip of the nose cone to cool the recirculation region. The gases are considered to be ideal, and the computational domain is axisymmetric. The analysis shows that the counterflowing jet has significant effects on the flowfield and reduces the heat load over the nose cone. The Helium jet is found to have a relatively more effective cooling performance.

Report on primate supply for biomedical scientific work in the UK. EUPREN UK Working Party.

PubMed

Owen, S; Thomas, C; West, P; Wolfensohn, S; Wood, M

1997-10-01

A Working Party of the UK group of European Primate Resources Network (EUPREN) considered primate supply for scientific work in the UK. Through a questionnaire, which achieved a very good response, it obtained details of primate use, sources and breeding in the UK and it put forward options to ensure that animal welfare is the best possible whilst ensuring continued supply. The questionnaire showed that contract research laboratories and pharmaceutical companies use about 80% of the 4233 primates used annually at the moment, with the rest accounted for by academic establishments and public sector laboratories. Fifty-four per cent are cynomolgus macaques (Macaca fascicularis), of which nearly 90% are captive-bred outside the European Union (EU), the remainder being bred in the UK. Nearly 90% of cynomolgus macaques are used by only five institutions. Thirty-seven per cent of primates used are marmosets (Callithrix jacchus jacchus), all of which are bred in the UK. Most of the rest are rhesus macaques (Macaca mulatta), about half of which are captive-bred outside the EU, the other half being bred in the UK. Overall primate use has increased from about 3000 per year in 1990 and users predict that requirements for all species except baboons (Papio sp.) will be maintained or increase. Marmoset breeding in the UK is already closely matched to use, and it could be increased reasonably easily if necessary. Some of the existing breeding centres of macaques in the UK would be prepared to consider expanding to supply others, although investment and imported breeding stock would be needed and it is likely that a large investment would be needed to breed a significant fraction of the macaque use in the UK. A further problem is that the users of only about 10% of the cynomolgus macaques said that they could replace this species by rhesus macaques, which are easier to breed in the UK. The questionnaire showed that much of the use of macaques would be transferred to other countries

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.

Restaurant Food Cooling Practices†

PubMed Central

BROWN, LAURA GREEN; RIPLEY, DANNY; BLADE, HENRY; REIMANN, DAVE; EVERSTINE, KAREN; NICHOLAS, DAVE; EGAN, JESSICA; KOKTAVY, NICOLE; QUILLIAM, DANIELA N.

2017-01-01

Improper food cooling practices are a significant cause of foodborne illness, yet little is known about restaurant food cooling practices. This study was conducted to examine food cooling practices in restaurants. Specifically, the study assesses the frequency with which restaurants meet U.S. Food and Drug Administration (FDA) recommendations aimed at reducing pathogen proliferation during food cooling. Members of the Centers for Disease Control and Prevention’s Environmental Health Specialists Network collected data on food cooling practices in 420 restaurants. The data collected indicate that many restaurants are not meeting FDA recommendations concerning cooling. Although most restaurant kitchen managers report that they have formal cooling processes (86%) and provide training to food workers on proper cooling (91%), many managers said that they do not have tested and verified cooling processes (39%), do not monitor time or temperature during cooling processes (41%), or do not calibrate thermometers used for monitoring temperatures (15%). Indeed, 86% of managers reported cooling processes that did not incorporate all FDA-recommended components. Additionally, restaurants do not always follow recommendations concerning specific cooling methods, such as refrigerating cooling food at shallow depths, ventilating cooling food, providing open-air space around the tops and sides of cooling food containers, and refraining from stacking cooling food containers on top of each other. Data from this study could be used by food safety programs and the restaurant industry to target training and intervention efforts concerning cooling practices. These efforts should focus on the most frequent poor cooling practices, as identified by this study. PMID:23212014

Restaurant food cooling practices.

PubMed

Brown, Laura Green; Ripley, Danny; Blade, Henry; Reimann, Dave; Everstine, Karen; Nicholas, Dave; Egan, Jessica; Koktavy, Nicole; Quilliam, Daniela N

2012-12-01

Improper food cooling practices are a significant cause of foodborne illness, yet little is known about restaurant food cooling practices. This study was conducted to examine food cooling practices in restaurants. Specifically, the study assesses the frequency with which restaurants meet U.S. Food and Drug Administration (FDA) recommendations aimed at reducing pathogen proliferation during food cooling. Members of the Centers for Disease Control and Prevention's Environmental Health Specialists Network collected data on food cooling practices in 420 restaurants. The data collected indicate that many restaurants are not meeting FDA recommendations concerning cooling. Although most restaurant kitchen managers report that they have formal cooling processes (86%) and provide training to food workers on proper cooling (91%), many managers said that they do not have tested and verified cooling processes (39%), do not monitor time or temperature during cooling processes (41%), or do not calibrate thermometers used for monitoring temperatures (15%). Indeed, 86% of managers reported cooling processes that did not incorporate all FDA-recommended components. Additionally, restaurants do not always follow recommendations concerning specific cooling methods, such as refrigerating cooling food at shallow depths, ventilating cooling food, providing open-air space around the tops and sides of cooling food containers, and refraining from stacking cooling food containers on top of each other. Data from this study could be used by food safety programs and the restaurant industry to target training and intervention efforts concerning cooling practices. These efforts should focus on the most frequent poor cooling practices, as identified by this study.

Parametric study of the lubrication of thrust loaded 120-mm bore ball bearings to 3 million DN

NASA Technical Reports Server (NTRS)

Signer, H.; Bamberger, E. N.; Zaretsky, E. V.

1973-01-01

A parametric study was performed with 120-mm bore angular-contact ball bearings under varying thrust loads, bearing and lubricant temperatures, and cooling and lubricant flow rates. Contact angles were nominally 20 and 24 deg with bearing speeds to 3 million DN. Endurance tests were run at 3 million DN and a temperature of 492 K (425 F) with 10 bearings having a nominal 24 deg contact angle at a thrust load of 22241 N (5000 lb). Bearing operating temperature, differences in temperatures between the inner and outer races, and bearing power consumption can be tuned to any desirable operating requirement by varying 4 parameters. These parameters are outer-race cooling, inner-race cooling, lubricant flow to the inner race, and oil inlet temperature. Preliminary endurance tests at 3 million DN and 492 K (425 F) indicate that long term bearing operation can be achieved with a high degree of reliability.

Changes needed to medicine in the UK before senior UK-trained doctors, working outside the UK, will return: questionnaire surveys undertaken between 2004 and 2015.

PubMed

Lambert, Trevor W; Smith, Fay; Goldacre, Michael J

2017-12-01

To report the changes to UK medicine which doctors who have emigrated tell us would increase their likelihood of returning to a career in UK medicine. Questionnaire survey. UK-trained medical graduates. Questionnaires were sent 11 years after graduation to 7158 doctors who qualified in 1993 and 1996 in the UK: 4763 questionnaires were returned. Questionnaires were sent 17 and 19 years after graduation to the same cohorts: 4554 questionnaires were returned. Comments from doctors working abroad about changes needed to UK medicine before they would return. Eleven years after graduation, 290 (6%) of respondents were working in medicine abroad; 277 (6%) were doing so 17/19 years after graduation. Eleven years after graduation, 53% of doctors working abroad indicated that they did not intend to return, and 71% did so 17/19 years after graduation. These respondents reported a number of changes which would need to be made to UK medicine in order to increase the likelihood of them returning. The most frequently mentioned changes cited concerned 'politics/management/funding', 'pay/pension', 'posts/security/opportunities', 'working conditions/hours', and 'factors outside medicine'. Policy attention to factors including funding, pay, management and particularly the clinical-political interface, working hours, and work-life balance may pay dividends for all, both in terms of persuading some established doctors to return and, perhaps more importantly, encouraging other, younger doctors to believe that the UK and the National Health Service can offer them a satisfying and rewarding career.

Accceleration of Fatigue Tests of Polymer Composite Materials by Using High-Frequency Loadings

NASA Astrophysics Data System (ADS)

Apinis, R.

2004-03-01

The possibility of using high-frequency loading in fatigue tests of polymer composite materials is discussed. A review of studies on the use of high-frequency loading of organic-, carbon-, and glass-fiber-reinforced plastics is presented. The results obtained are compared with those found in conventional low-frequency loadings. A rig for fatigue tests of rigid materials at loading frequencies to 500 Hz is described, and results for an LM-L1 unidirectional glass-fiber plastic in loadings with frequencies of 17 and 400 Hz are given. These results confirm that it is possible to accelerate the fatigue testing of polymer composite materials by considerably increasing the loading frequency. The necessary condition for using this method is an intense cooling of specimens to prevent them from vibration heating.

Integration of active and passive cool roof system for attic temperature reduction

NASA Astrophysics Data System (ADS)

Yew, Ming Chian; Yew, Ming Kun; Saw, Lip Huat; Durairaj, Rajkumar

2017-04-01

The aim of this project is to study the capability of cool roof system in the reduction of heat transmission through metal roof into an attic. The cool roof system is designed in active and passive methods to reduce the thermal loads imposed to a building. Two main features are introduced to this cool roof system, which is thermal insulation coating (TIC) and moving air cavity (MAC) that served as active and passive manner, respectively. For MAC, two designs are introduced. Normal MAC is fabricated by six aluminium tubes whereby each aluminium tube is made up by sticking up of five aluminium cans. While improved MAC is also made by six aluminium tubes whereby each aluminium tube is custom made from steel rods and aluminium foils. MAC provides ventilation and heat reflection under the metal roof before the heat transfer into attic. It also coupled with three solar powered fans to increase heat flow inside the channel. The cool roof that incorporated TIC, MAC with solar powered fans and opened attic inlet showed a significant improvement with a reduction of up to 14 °C in the attic temperature compared to conventional roof 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.

Advanced Carbon Materials Center Established At UK

Science.gov Websites

UK Home Academics Athletics Medical Center Research Site Index Search UK University Master ] [research at UK] Advanced Carbon Materials Center Established At UK The tiny but mighty nanotube will continue to be the subject of several research projects at the University of Kentucky, thanks in part to a

Does Short-Duration Heat Exposure at a Matched Cardiovascular Intensity Improve Intermittent-Running Performance in a Cool Environment?

PubMed

Philp, Calvin P; Buchheit, Martin; Kitic, Cecilia M; Minson, Christopher T; Fell, James W

2017-07-01

To investigate whether a 5-d cycling training block in the heat (35°C) in Australian Rules footballers was superior to exercising at the same relative intensity in cool conditions (15°C) for improving intermittent-running performance in a cool environment (<18°C). Using a parallel-group design, 12 semiprofessional football players performed 5 d of cycling exercise (70% heart-rate reserve [HRR] for 45 min [5 × 50-min sessions in total]) in a hot (HEAT, 35°C ± 1°C, 56% ± 9% RH) or cool environment (COOL, 15°C ± 3°C, 81% ± 10% RH). A 30-15 Intermittent Fitness Test to assess intermittent running performance (V IFT ) was conducted in a cool environment (17°C ± 2°C, 58 ± 5% RH) before and twice after (1 and 3 d) the intervention. There was a likely small increase in V IFT in each group (HEAT, 0.5 ± 0.3 km/h, 1.5 ± 0.8 × smallest worthwhile change [SWC]; COOL, 0.4 ± 0.4 km/h, 1.6 ± 1.2 × SWC) 3 d postintervention, with no difference in change between the groups (0.5% ± 1.9%, 0.4 ± 1.4 × SWC). Cycle power output during the intervention was almost certainly lower in the HEAT group (HEAT 1.8 ± 0.2 W/kg vs COOL 2.5 ± 0.3 W/kg, -21.7 ± 3.2 × SWC, 100/0/0). When cardiovascularexercise intensity is matched (ie, 70% HRR) between environmental conditions, there is no additional performance benefit from short-duration moderate-intensity heat exposure (5 × 50 min) for semiprofessional footballers exercising in cool conditions. However, the similar positive adaptations may occur in HEAT with 30% lower mechanical load, which may be of interest for load management during intense training or rehabilitation phases.

Film cooling air pocket in a closed loop cooled airfoil

DOEpatents

Yu, Yufeng Phillip; Itzel, Gary Michael; Osgood, Sarah Jane; Bagepalli, Radhakrishna; Webbon, Waylon Willard; Burdgick, Steven Sebastian

2002-01-01

Turbine stator vane segments have radially inner and outer walls with vanes extending between them. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. To provide for air film cooing of select portions of the airfoil outer surface, at least one air pocket is defined on a wall of at least one of the cavities. Each air pocket is substantially closed with respect to the cooling medium in the cavity and cooling air pumped to the air pocket flows through outlet apertures in the wall of the airfoil to cool the same.

Changes needed to medicine in the UK before senior UK-trained doctors, working outside the UK, will return: questionnaire surveys undertaken between 2004 and 2015

PubMed Central

Lambert, Trevor W; Goldacre, Michael J

2017-01-01

Objective To report the changes to UK medicine which doctors who have emigrated tell us would increase their likelihood of returning to a career in UK medicine. Design Questionnaire survey. Setting UK-trained medical graduates. Participants Questionnaires were sent 11 years after graduation to 7158 doctors who qualified in 1993 and 1996 in the UK: 4763 questionnaires were returned. Questionnaires were sent 17 and 19 years after graduation to the same cohorts: 4554 questionnaires were returned. Main outcome measures Comments from doctors working abroad about changes needed to UK medicine before they would return. Results Eleven years after graduation, 290 (6%) of respondents were working in medicine abroad; 277 (6%) were doing so 17/19 years after graduation. Eleven years after graduation, 53% of doctors working abroad indicated that they did not intend to return, and 71% did so 17/19 years after graduation. These respondents reported a number of changes which would need to be made to UK medicine in order to increase the likelihood of them returning. The most frequently mentioned changes cited concerned ‘politics/management/funding’, ‘pay/pension’, ‘posts/security/opportunities’, ‘working conditions/hours’, and ‘factors outside medicine’. Conclusions Policy attention to factors including funding, pay, management and particularly the clinical–political interface, working hours, and work–life balance may pay dividends for all, both in terms of persuading some established doctors to return and, perhaps more importantly, encouraging other, younger doctors to believe that the UK and the National Health Service can offer them a satisfying and rewarding career. PMID:29230305

Albion: the UK 3rd generation high-performance thermal imaging programme

NASA Astrophysics Data System (ADS)

McEwen, R. K.; Lupton, M.; Lawrence, M.; Knowles, P.; Wilson, M.; Dennis, P. N. J.; Gordon, N. T.; Lees, D. J.; Parsons, J. F.

2007-04-01

The first generation of high performance thermal imaging sensors in the UK was based on two axis opto-mechanical scanning systems and small (4-16 element) arrays of the SPRITE detector, developed during the 1970s. Almost two decades later, a 2nd Generation system, STAIRS C was introduced, based on single axis scanning and a long linear array of approximately 3000 elements. The UK has now begun the industrialisation of 3 rd Generation High Performance Thermal Imaging under a programme known as "Albion". Three new high performance cadmium mercury telluride arrays are being manufactured. The CMT material is grown by MOVPE on low cost substrates and bump bonded to the silicon read out circuit (ROIC). To maintain low production costs, all three detectors are designed to fit with existing standard Integrated Detector Cooling Assemblies (IDCAs). The two largest focal planes are conventional devices operating in the MWIR and LWIR spectral bands. A smaller format LWIR device is also described which has a smart ROIC, enabling much longer stare times than are feasible with conventional pixel circuits, thus achieving very high sensitivity. A new reference surface technology for thermal imaging sensors is described, based on Negative Luminescence (NL), which offers several advantages over conventional peltier references, improving the quality of the Non-Uniformity Correction (NUC) algorithms.

Closed circuit steam cooled turbine shroud and method for steam cooling turbine shroud

DOEpatents

Burdgick, Steven Sebastian; Sexton, Brendan Francis; Kellock, Iain Robertson

2002-01-01

A turbine shroud cooling cavity is partitioned to define a plurality of cooling chambers for sequentially receiving cooling steam and impingement cooling of the radially inner wall of the shoud. An impingement baffle is provided in each cooling chamber for receiving the cooling media from a cooling media inlet in the case of the first chamber or from the immediately upstream chamber in the case of the second through fourth chambers and includes a plurality of impingement holes for effecting the impingement cooling of the shroud inner wall.

Adaption of the LHC cold mass cooling system to the requirements of the Future Circular Collider (FCC)

NASA Astrophysics Data System (ADS)

Kotnig, C.; Tavian, L.; Brenn, G.

2017-12-01

The cooling of the superconducting magnet cold masses with superfluid helium (He II) is a well-established concept successfully in operation for years in the LHC. Consequently, its application for the cooling of FCC magnets is an obvious option. The 12-kW heat loads distributed over 10-km long sectors not only require an adaption of the magnet bayonet heat exchangers but also present new challenges to the cryogenic plants, the distribution system and the control strategy. This paper recalls the basic LHC cooling concept with superfluid helium and defines the main parameters for the adaption to the FCC requirements. Pressure drop and hydrostatic head are developed in the distribution and pumping systems; their impact on the magnet temperature profile and the corresponding cooling efficiency is presented and compared for different distribution and pumping schemes.

SMA foil-based elastocaloric cooling: from material behavior to device engineering

NASA Astrophysics Data System (ADS)

Bruederlin, F.; Ossmer, H.; Wendler, F.; Miyazaki, S.; Kohl, M.

2017-10-01

The elastocaloric effect associated with the stress-induced first order phase transformation in pseudoelastic shape memory alloy (SMA) films and foils is of special interest for cooling applications on a miniature scale enabling fast heat transfer and high cycling frequencies as well as tunable transformation temperatures. The focus is on TiNi-based materials having the potential to meet the various challenges associated with elastocaloric cooling including large adiabatic temperature change and ultra-low fatigue. The evolution of strain and temperature bands during tensile load cycling is investigated with respect to strain and strain-rate by in situ digital image correlation and infrared thermography with a spatial resolution in the order of 25 µm. Major design issues and challenges in fabrication of SMA film-based elastocaloric cooling devices are discussed including the efficiency of heat transfer as well as force recovery to enhance the coefficient of performance (COP) on the system level. Advanced demonstrators show a temperature span of 13 °C after 30 s, while the COP of the overall device reaches almost 10% of Carnot efficiency.

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. .

Optimal load scheduling in commercial and residential microgrids

NASA Astrophysics Data System (ADS)

Ganji Tanha, Mohammad Mahdi

Residential and commercial electricity customers use more than two third of the total energy consumed in the United States, representing a significant resource of demand response. Price-based demand response, which is in response to changes in electricity prices, represents the adjustments in load through optimal load scheduling (OLS). In this study, an efficient model for OLS is developed for residential and commercial microgrids which include aggregated loads in single-units and communal loads. Single unit loads which include fixed, adjustable and shiftable loads are controllable by the unit occupants. Communal loads which include pool pumps, elevators and central heating/cooling systems are shared among the units. In order to optimally schedule residential and commercial loads, a community-based optimal load scheduling (CBOLS) is proposed in this thesis. The CBOLS schedule considers hourly market prices, occupants' comfort level, and microgrid operation constraints. The CBOLS' objective in residential and commercial microgrids is the constrained minimization of the total cost of supplying the aggregator load, defined as the microgrid load minus the microgrid generation. This problem is represented by a large-scale mixed-integer optimization for supplying single-unit and communal loads. The Lagrangian relaxation methodology is used to relax the linking communal load constraint and decompose the independent single-unit functions into subproblems which can be solved in parallel. The optimal solution is acceptable if the aggregator load limit and the duality gap are within the bounds. If any of the proposed criteria is not satisfied, the Lagrangian multiplier will be updated and a new optimal load schedule will be regenerated until both constraints are satisfied. The proposed method is applied to several case studies and the results are presented for the Galvin Center load on the 16th floor of the IIT Tower in Chicago.

Algae inhibition experiment and load characteristics of the algae solution

NASA Astrophysics Data System (ADS)

Xiong, L.; Gao, J. X.; Zhang, Y. X.; Yang, Z. K.; Zhang, D. Q.; He, W.

2016-08-01

It is necessary to inhibit microbial growth in an industrial cooling water system. This paper has developed a Monopolar/Bipolar polarity high voltage pulser with load adaptability for an algal experimental study. The load characteristics of the Chlorella pyrenoidosa solution were examined, and it was found that the solution load is resistive. The resistance is related to the plate area, concentration, and temperature of the solution. Furthermore, the pulser's treatment actually inhibits the algae cell growth. This article also explores the influence of various parameters of electric pulses on the algal effect. After the experiment, the optimum pulse parameters were determined to be an electric field intensity of 750 V/cm, a pulse width per second of 120μs, and monopolar polarity.

Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving.

PubMed

Li, Jiaming; de Melo, Leonardo F; Luo, Le

2017-03-30

We present a cooling method for a cold Fermi gas by parametrically driving atomic motions in a crossed-beam optical dipole trap (ODT). Our method employs the anharmonicity of the ODT, in which the hotter atoms at the edge of the trap feel the anharmonic components of the trapping potential, while the colder atoms in the center of the trap feel the harmonic one. By modulating the trap depth with frequencies that are resonant with the anharmonic components, we selectively excite the hotter atoms out of the trap while keeping the colder atoms in the trap, generating parametric cooling. This experimental protocol starts with a magneto-optical trap (MOT) that is loaded by a Zeeman slower. The precooled atoms in the MOT are then transferred to an ODT, and a bias magnetic field is applied to create an interacting Fermi gas. We then lower the trapping potential to prepare a cold Fermi gas near the degenerate temperature. After that, we sweep the magnetic field to the noninteracting regime of the Fermi gas, in which the parametric cooling can be manifested by modulating the intensity of the optical trapping beams. We find that the parametric cooling effect strongly depends on the modulation frequencies and amplitudes. With the optimized frequency and amplitude, we measure the dependence of the cloud energy on the modulation time. We observe that the cloud energy is changed in an anisotropic way, where the energy of the axial direction is significantly reduced by parametric driving. The cooling effect is limited to the axial direction because the dominant anharmonicity of the crossed-beam ODT is along the axial direction. Finally, we propose to extend this protocol for the trapping potentials of large anharmonicity in all directions, which provides a promising scheme for cooling quantum gases using external driving.

Microelectromechanical System (MEMS) Device Being Developed for Active Cooling and Temperature Control

NASA Technical Reports Server (NTRS)

Beach, Duane E.

2003-01-01

High-capacity cooling options remain limited for many small-scale applications such as microelectronic components, miniature sensors, and microsystems. A microelectromechanical system (MEMS) using a Stirling thermodynamic cycle to provide cooling or heating directly to a thermally loaded surface is being developed at the NASA Glenn Research Center to meet this need. The device can be used strictly in the cooling mode or can be switched between cooling and heating modes in milliseconds for precise temperature control. Fabrication and assembly employ techniques routinely used in the semiconductor processing industry. Benefits of the MEMS cooler include scalability to fractions of a millimeter, modularity for increased capacity and staging to low temperatures, simple interfaces, limited failure modes, and minimal induced vibration. The MEMS cooler has potential applications across a broad range of industries such as the biomedical, computer, automotive, and aerospace industries. The basic capabilities it provides can be categorized into four key areas: 1) Extended environmental temperature range in harsh environments; 2) Lower operating temperatures for electronics and other components; 3) Precision spatial and temporal thermal control for temperature-sensitive devices; and 4) The enabling of microsystem devices that require active cooling and/or temperature control. The rapidly expanding capabilities of semiconductor processing in general, and microsystems packaging in particular, present a new opportunity to extend Stirling-cycle cooling to the MEMS domain. The comparatively high capacity and efficiency possible with a MEMS Stirling cooler provides a level of active cooling that is impossible at the microscale with current state-of-the-art techniques. The MEMS cooler technology builds on decades of research at Glenn on Stirling-cycle machines, and capitalizes on Glenn s emerging microsystems capabilities.

UK Announces Intention to Join ESO

NASA Astrophysics Data System (ADS)

2000-11-01

Summary The Particle Physics and Astronomy Research Council (PPARC) , the UK's strategic science investment agency, today announced that the government of the United Kingdom is making funds available that provide a baseline for this country to join the European Southern Observatory (ESO) . The ESO Director General, Dr. Catherine Cesarsky , and the ESO Community warmly welcome this move towards fuller integration in European astronomy. "With the UK as a potential member country of ESO, our joint opportunities for front-line research and technology will grow significantly", she said. "This announcement is a clear sign of confidence in ESO's abilities, most recently demonstrated with the construction and operation of the unique Very Large Telescope (VLT) on Paranal. Together we will look forward with confidence towards new, exciting projects in ground-based astronomy." It was decided earlier this year to place the 4-m UK Visible and Infrared Survey Telescope (VISTA) at Paranal, cf. ESO Press Release 03/00. Following negotiations between ESO and PPARC, a detailed proposal for the associated UK/ESO Agreement with the various entry modalities will now be presented to the ESO Council for approval. Before this Agreement can enter into force, the ESO Convention and associated protocols must also be ratified by the UK Parliament. Research and key technologies According to the PPARC press release, increased funding for science, announced by the UK government today, will enable UK astronomers to prepare for the next generation of telescopes and expand their current telescope portfolio through membership of the European Southern Observatory (ESO). The uplift to its baseline budget will enable PPARC to enter into final negotiations for UK membership of the ESO. This will ensure that UK astronomers, together with their colleagues in the ESO member states, are actively involved in global scale preparations for the next generation of astronomy facilities. among these are ALMA

Superlattice-based thin-film thermoelectric modules with high cooling fluxes

PubMed Central

Bulman, Gary; Barletta, Phil; Lewis, Jay; Baldasaro, Nicholas; Manno, Michael; Bar-Cohen, Avram; Yang, Bao

2016-01-01

In present-day high-performance electronic components, the generated heat loads result in unacceptably high junction temperatures and reduced component lifetimes. Thermoelectric modules can, in principle, enhance heat removal and reduce the temperatures of such electronic devices. However, state-of-the-art bulk thermoelectric modules have a maximum cooling flux qmax of only about 10 W cm−2, while state-of-the art commercial thin-film modules have a qmax <100 W cm−2. Such flux values are insufficient for thermal management of modern high-power devices. Here we show that cooling fluxes of 258 W cm−2 can be achieved in thin-film Bi2Te3-based superlattice thermoelectric modules. These devices utilize a p-type Sb2Te3/Bi2Te3 superlattice and n-type δ-doped Bi2Te3−xSex, both of which are grown heteroepitaxially using metalorganic chemical vapour deposition. We anticipate that the demonstration of these high-cooling-flux modules will have far-reaching impacts in diverse applications, such as advanced computer processors, radio-frequency power devices, quantum cascade lasers and DNA micro-arrays. PMID:26757675

Acoustic and Thermal Testing of an Integrated Multilayer Insulation and Broad Area Cooling Shield System

NASA Technical Reports Server (NTRS)

Wood, Jessica J.; Foster, Lee W.

2013-01-01

A Multilayer Insulation (MLI) and Broad Area Cooling (BAC) shield thermal control system shows promise for long-duration storage of cryogenic propellant. The NASA Cryogenic Propellant Storage and Transfer (CPST) project is investigating the thermal and structural performance of this tank-applied integrated system. The MLI/BAC Shield Acoustic and Thermal Test was performed to evaluate the MLI/BAC shield's structural performance by subjecting it to worst-case launch acoustic loads. Identical thermal tests using Liquid Nitrogen (LN2) were performed before and after the acoustic test. The data from these tests was compared to determine if any degradation occurred in the thermal performance of the system as a result of exposure to the acoustic loads. The thermal test series consisted of two primary components: a passive boil-off test to evaluate the MLI performance and an active cooling test to evaluate the integrated MLI/BAC shield system with chilled vapor circulating through the BAC shield tubes. The acoustic test used loads closely matching the worst-case envelope of all launch vehicles currently under consideration for CPST. Acoustic test results yielded reasonable responses for the given load. The thermal test matrix was completed prior to the acoustic test and successfully repeated after the acoustic test. Data was compared and yielded near identical results, indicating that the MLI/BAC shield configuration tested in this series is an option for structurally implementing this thermal control system concept.

Selecting a Control Strategy for Plug and Process Loads

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

Lobato, C.; Sheppy, M.; Brackney, L.

2012-09-01

Plug and Process Loads (PPLs) are building loads that are not related to general lighting, heating, ventilation, cooling, and water heating, and typically do not provide comfort to the building occupants. PPLs in commercial buildings account for almost 5% of U.S. primary energy consumption. On an individual building level, they account for approximately 25% of the total electrical load in a minimally code-compliant commercial building, and can exceed 50% in an ultra-high efficiency building such as the National Renewable Energy Laboratory's (NREL) Research Support Facility (RSF) (Lobato et al. 2010). Minimizing these loads is a primary challenge in the designmore » and operation of an energy-efficient building. A complex array of technologies that measure and manage PPLs has emerged in the marketplace. Some fall short of manufacturer performance claims, however. NREL has been actively engaged in developing an evaluation and selection process for PPLs control, and is using this process to evaluate a range of technologies for active PPLs management that will cap RSF plug loads. Using a control strategy to match plug load use to users' required job functions is a huge untapped potential for energy savings.« less

To cool, but not too cool: that is the question--immersion cooling for hyperthermia.

PubMed

Taylor, Nigel A S; Caldwell, Joanne N; Van den Heuvel, Anne M J; Patterson, Mark J

2008-11-01

Patient cooling time can impact upon the prognosis of heat illness. Although ice-cold-water immersion will rapidly extract heat, access to ice or cold water may be limited in hot climates. Indeed, some have concerns regarding the sudden cold-water immersion of hyperthermic individuals, whereas others believe that cutaneous vasoconstriction may reduce convective heat transfer from the core. It was hypothesized that warmer immersion temperatures, which induce less powerful vasoconstriction, may still facilitate rapid cooling in hyperthermic individuals. Eight males participated in three trials and were heated to an esophageal temperature of 39.5 degrees C by exercising in the heat (36 degrees C, 50% relative humidity) while wearing a water-perfusion garment (40 degrees C). Subjects were cooled using each of the following methods: air (20-22 degrees C), cold-water immersion (14 degrees C), and temperate-water immersion (26 degrees C). The time to reach an esophageal temperature of 37.5 degrees C averaged 22.81 min (air), 2.16 min (cold), and 2.91 min (temperate). Whereas each of the between-trial comparisons was statistically significant (P < 0.05), cooling in temperate water took only marginally longer than that in cold water, and one cannot imagine that the 45-s cooling time difference would have any meaningful physiological or clinical implications. It is assumed that this rapid heat loss was due to a less powerful peripheral vasoconstrictor response, with central heat being more rapidly transported to the skin surface for dissipation. Although the core-to-water thermal gradient was much smaller with temperate-water cooling, greater skin and deeper tissue blood flows would support a superior convective heat delivery. Thus, a sustained physiological mechanism (blood flow) appears to have countered a less powerful thermal gradient, resulting in clinically insignificant differences in heat extraction between the cold and temperate cooling trials.

Long Term Large Scale river nutrient changes across the UK

NASA Astrophysics Data System (ADS)

Bell, Victoria; Naden, Pam; Tipping, Ed; Davies, Helen; Davies, Jessica; Dragosits, Ulli; Muhammed, Shibu; Quinton, John; Stuart, Marianne; Whitmore, Andy; Wu, Lianhai

2017-04-01

During recent decades and centuries, pools and fluxes of Carbon, Nitrogen and Phosphorus (C, N and P) in UK rivers and ecosystems have been transformed by the spread and fertiliser-based intensification of agriculture (necessary to sustain human populations), by atmospheric pollution, by human waste (rising in line with population growth), and now by climate change. The principal objective of the UK's NERC-funded Macronutrients LTLS research project has been to account for observable terrestrial and aquatic pools, concentrations and fluxes of C, N and P on the basis of past inputs, biotic and abiotic interactions, and transport processes. More specifically, over the last 200 years, what have been the temporal responses of plant and soil nutrient pools in different UK catchments to nutrient enrichment, and what have been the consequent effects on nutrient transfers from land to the atmosphere, freshwaters and estuaries? The work described here addresses the second question by providing an integrated quantitative description of the interlinked land and water pools and annual fluxes of C, N and P for UK catchments over time. A national-scale modelling environment has been developed, combining simple physically-based gridded models that can be parameterised using recent observations before application to long timescales. The LTLS Integrated Model (LTLS-IM) uses readily-available driving data (climate, land-use, nutrient inputs, topography), and model estimates of both terrestrial and freshwater nutrient loads have been compared with measurements from sites across the UK. Here, the focus is on the freshwater nutrient component of the LTLS-IM, but the terrestrial nutrient inputs required for this are provided by models of nutrient processes in semi-natural and agricultural systems, and from simple models of nutrients arising from human waste. In the freshwater model, lateral routing of dissolved and particulate nutrients and within-river processing such as

Short-term cooling increases serum triglycerides and small high-density lipoprotein levels in humans.

PubMed

Hoeke, Geerte; Nahon, Kimberly J; Bakker, Leontine E H; Norkauer, Sabine S C; Dinnes, Donna L M; Kockx, Maaike; Lichtenstein, Laeticia; Drettwan, Diana; Reifel-Miller, Anne; Coskun, Tamer; Pagel, Philipp; Romijn, Fred P H T M; Cobbaert, Christa M; Jazet, Ingrid M; Martinez, Laurent O; Kritharides, Leonard; Berbée, Jimmy F P; Boon, Mariëtte R; Rensen, Patrick C N

Cold exposure and β3-adrenergic receptor agonism, which both activate brown adipose tissue, markedly influence lipoprotein metabolism by enhancing lipoprotein lipase-mediated catabolism of triglyceride-rich lipoproteins and increasing plasma high-density lipoprotein (HDL) levels and functionality in mice. However, the effect of short-term cooling on human lipid and lipoprotein metabolism remained largely elusive. The objective was to assess the effect of short-term cooling on the serum lipoprotein profile and HDL functionality in men. Body mass index-matched young, lean men were exposed to a personalized cooling protocol for 2 hours. Before and after cooling, serum samples were collected for analysis of lipids and lipoprotein composition by 1 H-nuclear magnetic resonance. Adenosine triphosphate-binding cassette A1 (ABCA1)-mediated cholesterol efflux capacity of HDL was measured using [ 3 H]cholesterol-loaded ABCA1-transfected Chinese hamster ovary cells. Short-term cooling increased serum levels of free fatty acids, triglycerides, and cholesterol. Cooling increased the concentration of large very low-density lipoprotein (VLDL) particles accompanied by increased mean size of VLDL particles. In addition, cooling enhanced the concentration of small LDL and small HDL particles as well as the cholesterol levels within these particles. The increase in small HDL was accompanied by increased ABCA1-dependent cholesterol efflux in vitro. Our data show that short-term cooling increases the concentration of large VLDL particles and increases the generation of small LDL and HDL particles. We interpret that cooling increases VLDL production and turnover, which results in formation of surface remnants that form small HDL particles that attract cellular cholesterol. Copyright © 2017 National Lipid Association. Published by Elsevier Inc. All rights reserved.

Load leveling on industrial refrigeration systems

NASA Astrophysics Data System (ADS)

Bierenbaum, H. S.; Kraus, A. D.

1982-01-01

A computer model was constructed of a brewery with a 2000 horsepower compressor/refrigeration system. The various conservation and load management options were simulated using the validated model. The savings available for implementing the most promising options were verified by trials in the brewery. Result show that an optimized methodology for implementing load leveling and energy conservation consisted of: (1) adjusting (or tuning) refrigeration systems controller variables to minimize unnecessary compressor starts, (2) The primary refrigeration system operating parameters, compressor suction pressure, and discharge pressure are carefully controlled (modulated) to satisfy product quality constraints (as well as in-process material cooling rates and temperature levels) and energy evaluating the energy cost savings associated with reject heat recovery, and (4) a decision is made to implement the reject heat recovery system based on a cost/benefits analysis.

Heat protection behaviour in the UK: results of an online survey after the 2013 heatwave.

PubMed

Khare, Swarna; Hajat, Shakoor; Kovats, Sari; Lefevre, Carmen E; de Bruin, Wändi Bruine; Dessai, Suraje; Bone, Angie

2015-09-10

The Heatwave Plan for England provides guidance for personal and home protection measures during heatwaves. Although studies in the USA, Australia and Europe have surveyed heat-related behaviours during heatwaves, few have been conducted in the UK. This study assesses personal and housing (at-home) behaviour and housing characteristics of the UK population during the 2013 heatwave. This paper analyses data from 1497 respondents of an online survey on heat protection measures and behaviour. Participants were asked questions about their behaviour during the 2013 heatwave, the characteristics of their current housing as well as about any negative health outcomes experienced due to the hot weather. We used multinomial logit regression to analyse personal and home heat protection behaviour and logistic regression to analyse characteristics of participants' current home (installed air conditioner, curtains etc.). We stratified the outcomes by age, sex, ethnicity, income, education and regional location. In 2013, for all heat-related illness (except tiredness), a higher proportion of those in the younger age groups reported symptoms compared with those in the older age groups. Women, higher income groups and those with higher education levels were found to be more likely to report always/often taking personal heat protective measures. The elderly were less likely to take some personal and home protective measures but were more likely to live in insulated homes and open windows at night to keep their home cool. Our study has found a high level of awareness of the actions to take during heatwaves in the UK, and has identified important demographic indicators of sections of the UK population that might benefit from additional or more targeted information. The health agencies should attempt to provide better information about heatwaves to those vulnerable (elderly, those at risk living in London, low income earners) or identify any barriers that might be preventing them from

Numerical Simulation of Wall Heat Load in Combustor Flow

NASA Astrophysics Data System (ADS)

Panara, D.; Hase, M.; Krebs, W.; Noll, B.

2007-09-01

Due to the major mechanism of NOx generation, there is generally a temperature trade off between improved cycle efficiency, material constraints and low NOx emission. The cycle efficiency is proportional to the highest cycle temperature, but unfortunately also the NOx production increases with increasing combustion temperature. For this reason, the modern combustion chamber design has been oriented towards lean premixed combustion system and more and more attention must be focused on the cooling air management. The challenge is to ensure sufficiently low temperature of the combustion liner with very low amount of film or effusion cooling air. Correct numerical prediction of temperature fields and wall heat load are therefore of critical interest in the modern combustion chamber design. Moreover, lean combustion technology has shown the appearance of thermo-acoustic instabilities which have to be taken into account in the simulation and, more in general, in the design of reliable combustion systems. In this framework, the present investigation addresses the capability of a commercial multiphysics code (ANSYS CFX) to correctly predict the wall heat load and the core flow temperature field in a scaled power generation combustion chamber with a simplified ceramic liner. Comparison are made with the experimental results from the ITS test rig at the University of Karlsruhe [1] and with a previous numerical campaign from [2]. In addition the effect of flow unsteadyness on the wall heat load is discussed showing some limitations of the traditional steady state flow thermal design.

The effect of transmitted HIV-1 drug resistance on pre-therapy viral load.

PubMed

Harrison, Linda; Castro, Hannah; Cane, Patricia; Pillay, Deenan; Booth, Clare; Phillips, Andrew; Geretti, Anna Maria; Dunn, David

2010-07-31

Reduced replication capacity of viruses expressing drug resistant mutations implies that patients with transmitted drug resistance (TDR) could have lower HIV RNA viral load than those infected with wild-type virus. We performed analysis using data from the UK HIV Drug Resistance Database and the UK CHIC study. Eligible patients had a resistance test performed between 1997 and 2007 while naive to antiretroviral therapy, were 16 years or older, and had a viral load and CD4 cell count measurement within 6 months of this test. Models were adjusted for CD4 cell count, viral subtype, ethnicity, risk group, sex, age, calendar year, clinical centre, and viral load assay. Of a total of 7994 patients included, 709 (9%) had TDR: 604 (85%) had resistance to one drug class only [350 nucleos(t)ide reverse transcriptase inhibitors (NRTIs), 164 non-nucleos(t)ide reverse transcriptase inhibitors (NNRTIs), 90 protease inhibitors (PIs)], 77 (11%) to two classes (42 NRTIs/NNRTIs, 31 NRTIs/PIs, 4 NNRTIs/PIs), and 28 (4%) had resistance to all three classes. The overall mean (SD) viral load at the time of resistance testing was 4.60 (0.82) log(10) copies/ml, and did not differ by class of TDR. However, patients harbouring M184V/I (n = 61) had a significantly lower viral load [adjusted mean difference -0.33 log10 copies/ml (95% CI -0.54 to -0.11), 53% lower (95% CI 22 to 71%), P = 0.002] compared to wild-type virus. Our study provides clear evidence of an in-vivo fitness cost associated with the M184V/I mutation independent of drug effects which select for this mutation. This was not observed for any other mutation, but true effects may have been obscured by reversion of initially resistant viruses to wild-type.

Performance Evaluation of a Thermal Load Reduction System in a Hyundai Sonata PHEV

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

Kreutzer, Cory J; Rugh, John P; Titov, Eugene V

Increased adoption of electric-drive vehicles (EDVs) requires overcoming hurdles including limited vehicle range. Vehicle cabin heating and cooling demand for occupant climate control requires energy from the main battery and has been shown to significantly degrade vehicle range. During peak cooling and heating conditions, climate control can require as much or more energy as propulsion. As part of an ongoing project, NREL and project partners Hyundai America Technical Center, Inc. (HATCI), Gentherm , Pittsburgh Glass Works (PGW), PPG Industries, Sekisui, 3M, and Hanon Systems developed a thermal load reduction system in order to reduce the range penalty associated with electricmore » vehicle climate control. Solar reflective paint, solar control glass, heated and cooled/ventilated seats, heated surfaces, and heated windshield with door demisters were integrated into a Hyundai Sonata plug-in hybrid electric vehicle (PHEV). Cold weather field-testing was conducted in Fairbanks, Alaska while warm weather testing was conducted in Death Valley, California to assess the system performance in comparison to the baseline production vehicle. In addition, environmental chamber testing at peak heating and cooling conditions was performed to assess the performance of the system in standardized conditions compared to the baseline. Experimental results are presented in this paper providing quantitative data to automobile manufacturers on the impact of climate control thermal load reduction technologies to increase the advanced thermal technology adoption and market penetration of electric drive vehicles.« less

Experimental Characterization and Modeling of Thermal Contact Resistance of Electric Machine Stator-to-Cooling Jacket Interface Under Interference Fit Loading

DOE PAGES

Cousineau, Justine Emily; Bennion, Kevin S.; Chieduko, Victor; ...

2018-05-08

Cooling of electric machines is a key to increasing power density and improving reliability. This paper focuses on the design of a machine using a cooling jacket wrapped around the stator. The thermal contact resistance (TCR) between the electric machine stator and cooling jacket is a significant factor in overall performance and is not well characterized. This interface is typically an interference fit subject to compressive pressure exceeding 5 MPa. An experimental investigation of this interface was carried out using a thermal transmittance setup using pressures between 5 and 10 MPa. Furthermore, the results were compared to currently available modelsmore » for contact resistance, and one model was adapted for prediction of TCR in future motor designs.« less

Experimental Characterization and Modeling of Thermal Contact Resistance of Electric Machine Stator-to-Cooling Jacket Interface Under Interference Fit Loading

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

Cousineau, Justine Emily; Bennion, Kevin S.; Chieduko, Victor

Cooling of electric machines is a key to increasing power density and improving reliability. This paper focuses on the design of a machine using a cooling jacket wrapped around the stator. The thermal contact resistance (TCR) between the electric machine stator and cooling jacket is a significant factor in overall performance and is not well characterized. This interface is typically an interference fit subject to compressive pressure exceeding 5 MPa. An experimental investigation of this interface was carried out using a thermal transmittance setup using pressures between 5 and 10 MPa. Furthermore, the results were compared to currently available modelsmore » for contact resistance, and one model was adapted for prediction of TCR in future motor designs.« less

Cooling of Gas Turbines. 2; Effectiveness of Rim Cooling of Blades

NASA Technical Reports Server (NTRS)

Wolfenstein, Lincoln; Meyer, Gene L.; McCarthy, John S.

1945-01-01

An analysis of rim cooling, which cools the blade by condition alone, was conducted. Gas temperatures ranged from 1300 degrees to 1900 degrees F and rim temperatures from 0 degrees to 1000 degrees F below gas temperatures. Results show that gas temperature increases up to 200 degrees F are permissible provided that the blades are cooled by 400 degrees to 500 degrees F below the gas temperature. Relatively small amounts of blade cooling, at constant gas temperature, give large increases in blade life. Dependence of rim cooling on heat-transfer coefficient, blade dimensions, and thermal conductivity is determined by a single parameter.

Building heating and cooling applications thermal energy storage program overview

NASA Technical Reports Server (NTRS)

Eissenberg, D. M.

1980-01-01

Thermal energy storage technology and development of building heating and cooling applications in the residential and commercial sectors is outlined. Three elements are identified to undergo an applications assessment, technology development, and demonstration. Emphasis is given to utility load management thermal energy system application where the stress is on the 'customer side of the meter'. Thermal storage subsystems for space conditioning and conservation means of increased thermal mass within the building envelope and by means of low-grade waste heat recovery are covered.

Physics with Cold Molecules Using Buffer Gas Cooling: Precision Measurement, Collisions, and Laser Cooling

NASA Astrophysics Data System (ADS)

Hutzler, Nicholas R.; Doyle, John M.

2014-06-01

Cryogenic buffer gas cooled beams and cells can be used to study many species, from atoms and polar molecules to biomolecules. We report on recent applications of this technique to improve the limit on the electron electric dipole moment [1], load polar molecules into a magnetic trap through optical pumping [2], perform chirally sensitive microwave spectroscopy on polyatomic molecules [3], progress towards magneto-optical trapping of polar molecules [4], and studies of atom-molecule sticking [5]. [1] The ACME Collaboration: J. Baron et al., Science 343, p. 269 (2014) [2] B. Hemmerling et al., arXiv:1310.2669, to appear in Phys. Rev. Lett. [3] D. Patterson, M. Schnell, & J. M. Doyle, Nature 497, p. 475 (2013) [4] H. Lu et al., arXiv:1310.3239, to appear in New. J. Phys. [5] J. Piskorski et al., under preparation

The UK population: how does it compare?

PubMed

Matheson, Jil

2010-01-01

This is the fourth demographic report for the UK, providing an overview of the latest statistics on the population. This year's article compares the UK with other European countries and a range of nations from around the world. Statistical comparisons are made for fertility, mortality, ageing, migration and population density. The UK has an ageing population, but one that is not ageing as rapidly as some other countries such as Germany, Italy and Japan. Although life expectation in the UK is improving in line with most western European countries, relatively high levels of fertility ensure that the proportion of the population that is young remains high. Around one in ten residents of the UK are foreign born, a lower proportion than many developed countries. UK population density has increased steadily and is the fourth highest in the EU.

Solar heating and cooling technical data and systems analysis

NASA Technical Reports Server (NTRS)

Christensen, D. L.

1976-01-01

The accomplishments of a project to study solar heating and air conditioning are outlined. Presentation materials (data packages, slides, charts, and visual aids) were developed. Bibliographies and source materials on materials and coatings, solar water heaters, systems analysis computer models, solar collectors and solar projects were developed. Detailed MIRADS computer formats for primary data parameters were developed and updated. The following data were included: climatic, architectural, topography, heating and cooling equipment, thermal loads, and economics. Data sources in each of these areas were identified as well as solar radiation data stations and instruments.

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.

Transient analysis and energy optimization of solar heating and cooling systems in various configurations

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

Calise, F.; Dentice d'Accadia, M.; Palombo, A.

2010-03-15

In this paper, a transient simulation model of solar-assisted heating and cooling systems (SHC) is presented. A detailed case study is also discussed, in which three different configurations are considered. In all cases, the SHC system is based on the coupling of evacuated solar collectors with a single-stage LiBr-H{sub 2}O absorption chiller, and a gas-fired boiler is also included for auxiliary heating, only during the winter season. In the first configuration, the cooling capacity of the absorption chiller and the solar collector area are designed on the basis of the maximum cooling load, and an electric chiller is used asmore » the auxiliary cooling system. The second layout is similar to the first one, but, in this case, the absorption chiller and the solar collector area are sized in order to balance only a fraction of the maximum cooling load. Finally, in the third configuration, there is no electric chiller, and the auxiliary gas-fired boiler is also used in summer to feed the absorption chiller, in case of scarce solar irradiation. The simulation model was developed using the TRNSYS software, and included the analysis of the dynamic behaviour of the building in which the SHC systems were supposed to be installed. The building was simulated using a single-lumped capacitance model. An economic model was also developed, in order to assess the operating and capital costs of the systems under analysis. Furthermore, a mixed heuristic-deterministic optimization algorithm was implemented, in order to determine the set of the synthesis/design variables that maximize the energy efficiency of each configuration under analysis. The results of the case study were analyzed on monthly and weekly basis, paying special attention to the energy and monetary flows of the standard and optimized configurations. The results are encouraging as for the potential of energy saving. On the contrary, the SHC systems appear still far from the economic profitability: however, this is

An investigation of the accuracy of the Merkel equation for evaporative cooling tower calculations. Waste heat management

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

Yadigaroglu, G.; Pastor, E.J.

1974-01-01

The exact differential equations governing heat and mass transfer and air flow in an evaporative, natural-draft cooling tower are presented. The Merkel equation is then derived starting from this exact formulation and showing all the approximations involved. The Merkel formulation lumps the sensible and the latent heat transfer together and considers a single enthalpy-difference driving force for the total heat transfer. The effect of the approximations inherent in the Merkel equation is investigated and analyzed by a series of parametric numerical calculations of cooling tower performance under various ambient conditions and load conditions.

Fuel and Core Design Options to Overcome the Heavy Metal Loading Limit and Improve Performance and Safety of Liquid Salt Cooled Reactors

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

Petrovic, Bojan; Maldonado, Ivan

2016-04-14

The research performed in this project addressed the issue of low heavy metal loading and the resulting reduced cycle length with increased refueling frequency, inherent to all FHR designs with solid, non-movable fuel based on TRISO particles. Studies performed here focused on AHTR type of reactor design with plate (“plank”) fuel. Proposal to FY12 NEUP entitled “Fuel and Core Design Options to Overcome the Heavy Metal Loading Limit and Improve Performance and Safety of Liquid Salt Cooled Reactors” was selected for award, and the 3-year project started in August 2012. A 4-month NCE was granted and the project completed onmore » December 31, 2015. The project was performed by Georgia Tech (Prof. Bojan Petrovic, PI) and University of Tennessee (Prof. Ivan Maldonado, Co-PI), with a total funding of $758,000 over 3 years. In addition to two Co-PIs, the project directly engaged 6 graduate students (at doctoral or MS level) and 2 postdoctoral researchers. Additionally, through senior design projects and graduate advanced design projects, another 23 undergraduate and 12 graduate students were exposed to and trained in the salt reactor technology. We see this as one of the important indicators of the project’s success and effectiveness. In the process, 1 journal article was published (with 3 journal articles in preparation), together with 8 peer-reviewed full conference papers, 8 peer-reviewed extended abstracts, as well as 1 doctoral dissertation and 2 master theses. The work included both development of models and methodologies needed to adequately analyze this type of reactor, fuel, and its fuel cycle, as well as extensive analyses and optimization of the fuel and core design.« less

Cooled-Spool Piston Compressor

NASA Technical Reports Server (NTRS)

Morris, Brian G.

1994-01-01

Proposed cooled-spool piston compressor driven by hydraulic power and features internal cooling of piston by flowing hydraulic fluid to limit temperature of compressed gas. Provides sufficient cooling for higher compression ratios or reactive gases. Unlike conventional piston compressors, all parts of compressed gas lie at all times within relatively short distance of cooled surface so that gas cooled more effectively.

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

Radial turbine cooling

NASA Technical Reports Server (NTRS)

Roelke, Richard J.

1992-01-01

The technology of high temperature cooled radial turbines is reviewed. Aerodynamic performance considerations are described. Heat transfer and structural analysis are addressed, and in doing so the following topics are covered: cooling considerations, hot side convection, coolant side convection, and rotor mechanical analysis. Cooled rotor concepts and fabrication are described, and the following are covered in this context: internally cooled rotor, hot isostatic pressure bonded rotor, laminated rotor, split blade rotor, and the NASA radial turbine program.

Cooling circuit for and method of cooling a gas turbine bucket

DOEpatents

Jacala, Ariel C. P.

2002-01-01

A closed internal cooling circuit for a gas turbine bucket includes axial supply and return passages in the dovetail of the bucket. A first radial outward supply passage provides cooling medium to and along a passageway adjacent the leading edge and then through serpentine arranged passageways within the airfoil to a chamber adjacent the airfoil tip. A second radial passage crosses over the radial return passage for supplying cooling medium to and along a pair of passageways along the trailing edge of the airfoil section. The last passageway of the serpentine passageways and the pair of passageways communicate one with the other in the chamber for returning spent cooling medium radially inwardly along divided return passageways to the return passage. In this manner, both the leading and trailing edges are cooled using the highest pressure, lowest temperature cooling medium.

The effect of heat transfer mode on heart rate responses and hysteresis during heating and cooling in the estuarine crocodile Crocodylus porosus.

PubMed

Franklin, Craig E; Seebacher, Frank

2003-04-01

The effect of heating and cooling on heart rate in the estuarine crocodile Crocodylus porosus was studied in response to different heat transfer mechanisms and heat loads. Three heating treatments were investigated. C. porosus were: (1) exposed to a radiant heat source under dry conditions; (2) heated via radiant energy while half-submerged in flowing water at 23 degrees C and (3) heated via convective transfer by increasing water temperature from 23 degrees C to 35 degrees C. Cooling was achieved in all treatments by removing the heat source and with C. porosus half-submerged in flowing water at 23 degrees C. In all treatments, the heart rate of C. porosus increased markedly in response to heating and decreased rapidly with the removal of the heat source. Heart rate during heating was significantly faster than during cooling at any given body temperature, i.e. there was a significant heart rate hysteresis. There were two identifiable responses to heating and cooling. During the initial stages of applying or removing the heat source, there was a dramatic increase or decrease in heart rate ('rapid response'), respectively, indicating a possible cardiac reflex. This rapid change in heart rate with only a small change or no change in body temperature (<0.5 degrees C) resulted in Q(10) values greater than 4000, calling into question the usefulness of this measure on heart rate during the initial stages of heating and cooling. In the later phases of heating and cooling, heart rate changed with body temperature, with Q(10) values of 2-3. The magnitude of the heart rate response differed between treatments, with radiant heating during submergence eliciting the smallest response. The heart rate of C. porosus outside of the 'rapid response' periods was found to be a function of the heat load experienced at the animal surface, as well as on the mode of heat transfer. Heart rate increased or decreased rapidly when C. porosus experienced large positive (above 25 W) or negative

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

Comments on ionization cooling channels

DOE PAGES

Neuffer, David

2017-09-25

Ionization cooling channels with a wide variety of characteristics and cooling properties are being developed. These channels can produce cooling performances that are largely consistent with the linear ionization cooling theory developed previously. In this study, we review ionization cooling theory, discuss its application to presently developing cooling channels, and discuss criteria for optimizing cooling.

Comments on ionization cooling channels

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

Neuffer, David

Ionization cooling channels with a wide variety of characteristics and cooling properties are being developed. These channels can produce cooling performances that are largely consistent with the linear ionization cooling theory developed previously. In this study, we review ionization cooling theory, discuss its application to presently developing cooling channels, and discuss criteria for optimizing cooling.

Thermal investigation of an internally cooled strut injector for scramjet application at moderate and hot gas conditions

NASA Astrophysics Data System (ADS)

Dröske, Nils C.; Förster, Felix J.; Weigand, Bernhard; von Wolfersdorf, Jens

2017-03-01

In this paper, we present a combined experimental and numerical approach to assess the thermal loads and the cooling mechanism of an internally cooled strut injector for a supersonic combustion ramjet. Infrared measurements of the injector surface are conducted at a moderate external flow temperature. In addition, the main flow field is investigated with the LITA technique. Main features of the cooling mechanism are identified based on experimental data. However, a full evaluation can only be obtained using a complex, conjugate CFD simulation, which couples the external and internal flow fields to the heat conduction inside the injector body. Furthermore, numerical simulations are also presented for hot gas conditions corresponding to combustion experiments. Both hydrogen, which would be used as fuel for flight tests, and air are considered as coolants. While the main features of the cooling mechanism will be shown to remain unchanged, the combustor wall temperature is found to have a significant influence on the cooling. This emphasizes the importance and the usefulness of such complex conjugate numerical simulations.

Venus Surface Power and Cooling System Design

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Mellott, Kenneth D.

2004-01-01

A radioisotope power and cooling system is designed to provide electrical power for the a probe operating on the surface of Venus. Most foreseeable electronics devices and sensors simply cannot operate at the 450 C ambient surface temperature of Venus. Because the mission duration is substantially long and the use of thermal mass to maintain an operable temperature range is likely impractical, some type of active refrigeration may be required to keep certain components at a temperature below ambient. The fundamental cooling requirements are comprised of the cold sink temperature, the hot sink temperature, and the amount of heat to be removed. In this instance, it is anticipated that electronics would have a nominal operating temperature of 300 C. Due to the highly thermal convective nature of the high-density atmosphere, the hot sink temperature was assumed to be 50 C, which provided a 500 C temperature of the cooler's heat rejecter to the ambient atmosphere. The majority of the heat load on the cooler is from the high temperature ambient surface environment on Venus. Assuming 5 cm radial thickness of ceramic blanket insulation, the ambient heat load was estimated at approximately 77 watts. With an estimated quantity of 10 watts of heat generation from electronics and sensors, and to accommodate some level of uncertainty, the total heat load requirement was rounded up to an even 100 watts. For the radioisotope Stirling power converter configuration designed, the Sage model predicts a thermodynamic power output capacity of 478.1 watts, which slightly exceeds the required 469.1 watts. The hot sink temperature is 1200 C, and the cold sink temperature is 500 C. The required heat input is 1740 watts. This gives a thermodynamic efficiency of 27.48 %. The maximum theoretically obtainable efficiency is 47.52 %. It is estimated that the mechanical efficiency of the power converter design is on the order of 85 %, based on experimental measurements taken from 500 watt power

Flow distribution analysis on the cooling tube network of ITER thermal shield

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

Nam, Kwanwoo; Chung, Wooho; Noh, Chang Hyun

2014-01-29

Thermal shield (TS) is to be installed between the vacuum vessel or the cryostat and the magnets in ITER tokamak to reduce the thermal radiation load to the magnets operating at 4.2K. The TS is cooled by pressurized helium gas at the inlet temperature of 80K. The cooling tube is welded on the TS panel surface and the composed flow network of the TS cooling tubes is complex. The flow rate in each panel should be matched to the thermal design value for effective radiation shielding. This paper presents one dimensional analysis on the flow distribution of cooling tube networkmore » for the ITER TS. The hydraulic cooling tube network is modeled by an electrical analogy. Only the cooling tube on the TS surface and its connecting pipe from the manifold are considered in the analysis model. Considering the frictional factor and the local loss in the cooling tube, the hydraulic resistance is expressed as a linear function with respect to mass flow rate. Sub-circuits in the TS are analyzed separately because each circuit is controlled by its own control valve independently. It is found that flow rates in some panels are insufficient compared with the design values. In order to improve the flow distribution, two kinds of design modifications are proposed. The first one is to connect the tubes of the adjacent panels. This will increase the resistance of the tube on the panel where the flow rate is excessive. The other design suggestion is that an orifice is installed at the exit of tube routing where the flow rate is to be reduced. The analysis for the design suggestions shows that the flow mal-distribution is improved significantly.« less

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.

Cooling characteristics of air cooled radial turbine blades

NASA Astrophysics Data System (ADS)

Sato, T.; Takeishi, K.; Matsuura, M.; Miyauchi, J.

The cooling design and the cooling characteristics of air cooled radial turbine wheels, which are designed for use with the gas generator turbine for the 400 horse power truck gas turbine engine, are presented. A high temperature and high speed test was performed under aerodynamically similar conditions to that of the prototype engine in order to confirm the metal temperature of the newly developed integrated casting wheels constructed of the superalloys INCO 713C. The test results compared with the analytical value, which was established on the basis of the results of the heat transfer test and the water flow test, are discussed.

Cool Vest

NASA Technical Reports Server (NTRS)

1982-01-01

ILC, Dover Division's lightweight cooling garment, called Cool Vest was designed to eliminate the harmful effects of heat stress; increases tolerance time in hot environments by almost 300 percent. Made of urethane-coated nylon used in Apollo, it works to keep the body cool, circulating chilled water throughout the lining by means of a small battery-powered pump. A pocket houses the pump, battery and the coolant which can be ice or a frozen gel, a valve control allows temperature regulation. One version is self-contained and portable for unrestrained movement, another has an umbilical line attached to an external source of coolant, such as standard tap water, when extended mobility is not required. It is reported from customers that the Cool Vest pays for itself in increased productivity in very high temperatures.

Residential Variable-Capacity Heat Pumps Sized to Heating Loads

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

Munk, Jeffrey D.; Jackson, Roderick K.; Odukomaiya, Adewale

2014-01-01

Variable capacity heat pumps are an emerging technology offering significant energy savings potential and improved efficiency. With conventional single-speed systems, it is important to appropriately size heat pumps for the cooling load as over-sizing would result in cycling and insufficient latent capacity required for humidity control. These appropriately sized systems are often under-sized for the heating load and require inefficient supplemental electric resistance heat to meet the heating demand. Variable capacity heat pumps address these shortcomings by providing an opportunity to intentionally size systems for the dominant heating season load without adverse effects of cycling or insufficient dehumidification in themore » cooling season. This intentionally-sized system could result in significant energy savings in the heating season, as the need for inefficient supplemental electric resistance heat is drastically reduced. This is a continuation of a study evaluating the energy consumption of variable capacity heat pumps installed in two unoccupied research homes in Farragut, a suburb of Knoxville, Tennessee. In this particular study, space conditioning systems are intentionally sized for the heating season loads to provide an opportunity to understand and evaluate the impact this would have on electric resistance heat use and dehumidification. The results and conclusions drawn through this research are valid and specific for portions of the Southeastern and Midwestern United States falling in the mixed-humid climate zone. While other regions in the U.S. do not experience this type of climate, this work provides a basis for, and can help understand the implications of other climate zones on residential space conditioning energy consumption. The data presented here will provide a framework for fine tuning residential building EnergyPlus models that are being developed.« less

Hybrid radiator cooling system

DOEpatents

France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

2016-03-15

A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

Analysis of the Thermal Loads on the KSTAR Cryogenic System

NASA Astrophysics Data System (ADS)

Kim, Y. S.; Oh, Y. K.; Kim, W. C.; Park, Y. M.; Lee, Y. J.; Jin, S. B.; Sa, J. W.; Choi, C. H.; Cho, K. W.; Bak, J. S.; Lee, G. S.

2004-06-01

A large-scale helium refrigeration system is one of the key components for the KSTAR (Korea Superconducting Tokamak Advanced Research) device. In the design of the refrigeration system, an estimation of the thermal loads on the cold mass is an important issue according to the operation scenario. The cold mass of the KSTAR device is about 250 tons including 30 superconducting (SC) coils and the magnet structure. In addition to the static thermal loads, pulsed thermal loads to the refrigeration system have been considered in the operation stage. The main pulsed thermal loads on magnet system are AC losses in the SC coils and eddy current losses in the magnet structure that depend on the magnetic field variation rate. The nuclear radiation loss due to plasma pulse operation is also considered. The designed cooling capacity of the refrigeration system is estimated to be about 9 kW at 4.5 K isothermal. In this paper, calculation of the various kinds of thermal loads on KSTAR cryogenic system and design of the large-scale helium refrigeration system are presented.

Local cooling reduces skin ischemia under surface pressure in rats: an assessment by wavelet analysis of laser Doppler blood flow oscillations.

PubMed

Jan, Yih-Kuen; Lee, Bernard; Liao, Fuyuan; Foreman, Robert D

2012-10-01

The objectives of this study were to investigate the effects of local cooling on skin blood flow response to prolonged surface pressure and to identify associated physiological controls mediating these responses using the wavelet analysis of blood flow oscillations in rats. Twelve Sprague-Dawley rats were randomly assigned to three protocols, including pressure with local cooling (Δt = -10 °C), pressure with local heating (Δt = 10 °C) and pressure without temperature changes. Pressure of 700 mmHg was applied to the right trochanter area of rats for 3 h. Skin blood flow was measured using laser Doppler flowmetry. The 3 h loading period was divided into non-overlapping 30 min epochs for the analysis of the changes of skin blood flow oscillations using wavelet spectral analysis. The wavelet amplitudes and powers of three frequencies (metabolic, neurogenic and myogenic) of skin blood flow oscillations were calculated. The results showed that after an initial loading period of 30 min, skin blood flow continually decreased under the conditions of pressure with heating and of pressure without temperature changes, but maintained stable under the condition of pressure with cooling. Wavelet analysis revealed that stable skin blood flow under pressure with cooling was attributed to changes in the metabolic and myogenic frequencies. This study demonstrates that local cooling may be useful for reducing ischemia of weight-bearing soft tissues that prevents pressure ulcers.

Local cooling reduces skin ischemia under surface pressure in rats: an assessment by wavelet analysis of laser Doppler blood flow oscillations

PubMed Central

Jan, Yih-Kuen; Lee, Bernard; Liao, Fuyuan; Foreman, Robert D.

2012-01-01

The objectives of this study were to investigate the effects of local cooling on skin blood flow response to prolonged surface pressure and to identify associated physiological controls mediating these responses using wavelet analysis of blood flow oscillations in rats. Twelve Sprague Dawley rats were randomly assigned into three protocols, including pressure with local cooling (Δt= −10°C), pressure with local heating (Δt= 10°C), and pressure without temperature changes. Pressure of 700 mmHg was applied to the right trochanter area of rats for 3 hours. Skin blood flow was measured using laser Doppler flowmetry. The 3-hour loading period was divided into non-overlapping 30 min epochs for analysis of the changes of skin blood flow oscillations using wavelet spectral analysis. The wavelet amplitudes and powers of three frequencies (metabolic, neurogenic and myogenic) of skin blood flow oscillations were calculated. The results showed that after an initial loading period of 30 min, skin blood flow continually decreased in the conditions of pressure with heating and of pressure without temperature changes, but maintained stable in the condition of pressure with cooling. Wavelet analysis revealed that stable skin blood flow under pressure with cooling was attributed to changes in the metabolic and myogenic frequencies. This study demonstrates that local cooling may be useful for reducing ischemia of weight-bearing soft tissues that prevents pressure ulcers. PMID:23010955

Thermal Load Considerations for Detonative Combustion-Based Gas Turbine Engines

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.; Perkins, H. Douglas

2004-01-01

An analysis was conducted to assess methods for, and performance implications of, cooling the passages (tubes) of a pulse detonation-based combustor conceptually installed in the core of a gas turbine engine typical of regional aircraft. Temperature-limited material stress criteria were developed from common-sense engineering practice, and available material properties. Validated, one-dimensional, numerical simulations were then used to explore a variety of cooling methods and establish whether or not they met the established criteria. Simulation output data from successful schemes were averaged and used in a cycle-deck engine simulation in order to assess the impact of the cooling method on overall performance. Results were compared to both a baseline engine equipped with a constant-pressure combustor and to one equipped with an idealized detonative combustor. Major findings indicate that thermal loads in these devices are large, but potentially manageable. However, the impact on performance can be substantial. Nearly one half of the ideally possible specific fuel consumption (SFC) reduction is lost due to cooling of the tubes. Details of the analysis are described, limitations are presented, and implications are discussed.

Closed Form Equations for the Preliminary Design of a Heat-Pipe-Cooled Leading Edge

NASA Technical Reports Server (NTRS)

Glass, David E.

1998-01-01

A set of closed form equations for the preliminary evaluation and design of a heat-pipe-cooled leading edge is presented. The set of equations can provide a leading-edge designer with a quick evaluation of the feasibility of using heat-pipe cooling. The heat pipes can be embedded in a metallic or composite structure. The maximum heat flux, total integrated heat load, and thermal properties of the structure and heat-pipe container are required input. The heat-pipe operating temperature, maximum surface temperature, heat-pipe length, and heat pipe-spacing can be estimated. Results using the design equations compared well with those from a 3-D finite element analysis for both a large and small radius leading edge.

Cooled Water Production System,

DTIC Science & Technology

The invention refers to the field of air conditioning and regards an apparatus for obtaining cooled water . The purpose of the invention is to develop...such a system for obtaining cooled water which would permit the maximum use of the cooling effect of the water -cooling tower.

Passive cooling and heating program at Oak Ridge National Laboratory for FY-1981

NASA Astrophysics Data System (ADS)

Shapira, H. B.; Kaplan, S. I.; Chester, C. V.

Construction was completed of an earth-sheltered, passively solar heated office-dormitory, the Joint Institute for Heavy Ion Research, designed at ORNL. Instrumentation of the building was designed, procured, and installed. Building performance will be monitored and compared with predictions of the DOE-2 code. A study of the incorporation of vegetation on architecture was conducted by the Harvard School of Design. A final report was issued which is a prototype handbook for the use of vegetation to reduce cooling loads in structures. An experiment to reduce the cooling requirement of mobile homes by shading with fast-growing vines was begun: a maintenance-oriented trellis was constructed and vines were planted. An RFP for the production of a prototype set of reflective insulating blinds was issued.

Cool Cities, Cool Planet (LBNL Science at the Theater)

ScienceCinema

Rosenfeld, Arthur; Pomerantz, Melvin; Levinson, Ronnen

2018-06-14

Science at the Theater: Berkeley Lab scientists discuss how cool roofs can cool your building, your city ... and our planet. Arthur Rosenfeld, Professor of Physics Emeritus at UC Berkeley, founded the Berkeley Lab Center for Building Science in 1974. He served on the California Energy Commission from 2000 to 2010 and is commonly referred to as California's godfather of energy efficiency. Melvin Pomerantz is a member of the Heat Island Group at Berkeley Lab. Trained as a physicist at UC Berkeley, he specializes in research on making cooler pavements and evaluating their effects. Ronnen Levinson is a staff scientist at Berkeley Lab and the acting leader of its Heat Island Group. He has developed cool roofing and paving materials and helped bring cool roof requirements into building energy efficiency standards.

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.

Tarp-Assisted Cooling as a Method of Whole-Body Cooling in Hyperthermic Individuals.

PubMed

Hosokawa, Yuri; Adams, William M; Belval, Luke N; Vandermark, Lesley W; Casa, Douglas J

2017-03-01

We investigated the efficacy of tarp-assisted cooling as a body cooling modality. Participants exercised on a motorized treadmill in hot conditions (ambient temperature 39.5°C [103.1°F], SD 3.1°C [5.58°F]; relative humidity 38.1% [SD 6.7%]) until they reached exercise-induced hyperthermia. After exercise, participants were cooled with either partial immersion using a tarp-assisted cooling method (water temperature 9.20°C [48.56°F], SD 2.81°C [5.06°F]) or passive cooling in a climatic chamber. There were no differences in exercise duration (mean difference=0.10 minutes; 95% CI -5.98 to 6.17 minutes or end exercise rectal temperature (mean difference=0.10°C [0.18°F]; 95% CI -0.05°C to 0.25°C [-0.09°F to 0.45°F] between tarp-assisted cooling (48.47 minutes [SD 8.27 minutes]; rectal temperature 39.73°C [103.51°F], SD 0.27°C [0.49°F]) and passive cooling (48.37 minutes [SD 7.10 minutes]; 39.63°C [103.33°F], SD 0.40°C [0.72°F]). Cooling time to rectal temperature 38.25°C (100.85°F) was significantly faster in tarp-assisted cooling (10.30 minutes [SD 1.33 minutes]) than passive cooling (42.78 [SD 5.87 minutes]). Cooling rates for tarp-assisted cooling and passive cooling were 0.17°C/min (0.31°F/min), SD 0.07°C/min (0.13°F/min) and 0.04°C/min (0.07°F/min), SD 0.01°C/min (0.02°F/min), respectively (mean difference=0.13°C [0.23°F]; 95% CI 0.09°C to 0.17°C [0.16°F to 0.31°F]. No sex differences were observed in tarp-assisted cooling rates (men 0.17°C/min [0.31°F/min], SD 0.07°C/min [0.13°F/min]; women 0.16°C/min [0.29°F/min], SD 0.07°C/min [0.13°F/min]; mean difference=0.02°C/min [0.04°F/min]; 95% CI -0.06°C/min to 0.10°C/min [-0.11°F/min to 0.18°F/min]). Women (0.04°C/min [0.07°F/min], SD 0.01°C/min [0.02°F/min]) had greater cooling rates than men (0.03°C/min [0.05°F/min], SD 0.01°C/min [0.02°F/min]) in passive cooling, with negligible clinical effect (mean difference=0.01°C/min [0.02°F/min]; 95% CI 0.001�

Cool Flame Quenching

NASA Technical Reports Server (NTRS)

Pearlman, Howard; Chapek, Richard

2001-01-01

Cool flame quenching distances are generally presumed to be larger than those associated with hot flames, because the quenching distance scales with the inverse of the flame propagation speed, and cool flame propagation speeds are often times slower than those associated with hot flames. To date, this presumption has never been put to a rigorous test, because unstirred, non-isothermal cool flame studies on Earth are complicated by natural convection. Moreover, the critical Peclet number (Pe) for quenching of cool flames has never been established and may not be the same as that associated with wall quenching due to conduction heat loss in hot flames, Pe approx. = 40-60. The objectives of this ground-based study are to: (1) better understand the role of conduction heat loss and species diffusion on cool flame quenching (i.e., Lewis number effects), (2) determine cool flame quenching distances (i.e, critical Peclet number, Pe) for different experimental parameters and vessel surface pretreatments, and (3) understand the mechanisms that govern the quenching distances in premixtures that support cool flames as well as hot flames induced by spark-ignition. Objective (3) poses a unique fire safety hazard if conditions exist where cool flame quenching distances are smaller than those associated with hot flames. For example, a significant, yet unexplored risk, can occur if a multi-stage ignition (a cool flame that transitions to a hot flame) occurs in a vessel size that is smaller than that associated with the hot quenching distance. To accomplish the above objectives, a variety of hydrocarbon-air mixtures will be tested in a static reactor at elevated temperature in the laboratory (1g). In addition, reactions with chemical induction times that are sufficiently short will be tested aboard NASA's KC-135 microgravity (mu-g) aircraft. The mu-g results will be compared to a numerical model that includes species diffusion, heat conduction, and a skeletal kinetic mechanism

Advanced Refrigerant-Based Cooling Technologies for Information and Communication Infrastructure (ARCTIC)

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

Salamon, Todd

2012-12-13

. Results of a 100 kW prototype data center installation of the refrigerant-based modular cooling technology were dramatic in terms of energy efficiency and the ability to cool high-heat-density equipment. The prototype data center installation consisted of 10 racks each loaded with 10 kW of high-heat-density IT equipment with the racks arranged in a standard hot-aisle/cold-aisle configuration with standard cabinet spacing. A typical chilled-water CRAC unit would require approximately 16 kW to cool such a heat load. In contrast, the refrigerant-based modular cooling technology required only 2.3 kW of power for the refrigerant pump and shelf-level fans, a reduction of 85 percent. Differences in hot-aisle and cold-aisle temperature were also substantially reduced, mitigating many issues that arise in purely air-based cooling systems, such as mixing of hot and cold air streams, or from placing high-heat-density equipment in close proximity. The technology is also such that it is able to retro-fit live equipment without service interruption, which is particularly important to the large installed ICT customer base, thereby providing a means of mitigating reliability and performance concerns during the installation, training and validation phases of product integration. Moreover, the refrigerant used in our approach, R134a, is a widely-used, non-toxic dielectric liquid which, unlike water, is non-conducting and non-corrosive and will not damage electronics in the case of a leak a triple-play win over alternative water-based liquid coolant technologies. Finally, through use of a pumped refrigerant, pressures are modest (~60 psi), and toxic lubricants and oils are not required, in contrast to compressorized refrigerant systems another environmental win. Project Activities - The ARCTIC project goal was to further develop and dramatically accelerate the commercialization of this game-changing, refrigerant-based, liquid-cooling technology and achieve a revolutionary increase in energy

Turbine blade cooling

DOEpatents

Staub, Fred Wolf; Willett, Fred Thomas

1999-07-20

A turbine rotor blade comprises a shank portion, a tip portion and an airfoil. The airfoil has a pressure side wall and a suction side wall that are interconnected by a plurality of partition sidewalls, defining an internal cooling passageway within the airfoil. The internal cooling passageway includes at least one radial outflow passageway to direct a cooling medium flow from the shank portion towards the tip portion and at least one radial inflow passageway to direct a cooling medium flow from the tip portion towards the shank portion. A number of mixing ribs are disposed on the partition sidewalls within the radial outflow passageways so as to enhance the thermal mixing of the cooling medium flow, thereby producing improved heat transfer over a broad range of the Buoyancy number.

Turbine blade cooling

DOEpatents

Staub, Fred Wolf; Willett, Fred Thomas

2000-01-01

A turbine rotor blade comprises a shank portion, a tip portion and an airfoil. The airfoil has a pressure side wall and a suction side wall that are interconnected by a plurality of partition sidewalls, defining an internal cooling passageway within the airfoil. The internal cooling passageway includes at least one radial outflow passageway to direct a cooling medium flow from the shank portion towards the tip portion and at least one radial inflow passageway to direct a cooling medium flow from the tip portion towards the shank portion. A number of mixing ribs are disposed on the partition sidewalls within the radial outflow passageways so as to enhance the thermal mixing of the cooling medium flow, thereby producing improved heat transfer over a broad range of the Buoyancy number.

Turbine blade cooling

DOEpatents

Staub, F.W.; Willett, F.T.

1999-07-20

A turbine rotor blade comprises a shank portion, a tip portion and an airfoil. The airfoil has a pressure side wall and a suction side wall that are interconnected by a plurality of partition sidewalls, defining an internal cooling passageway within the airfoil. The internal cooling passageway includes at least one radial outflow passageway to direct a cooling medium flow from the shank portion towards the tip portion and at least one radial inflow passageway to direct a cooling medium flow from the tip portion towards the shank portion. A number of mixing ribs are disposed on the partition sidewalls within the radial outflow passageways so as to enhance the thermal mixing of the cooling medium flow, thereby producing improved heat transfer over a broad range of the Buoyancy number. 13 figs.

The UK Nitrate Time Bomb (Invited)

NASA Astrophysics Data System (ADS)

Ward, R.; Wang, L.; Stuart, M.; Bloomfield, J.; Gooddy, D.; Lewis, M.; McKenzie, A.

2013-12-01

The developed world has benefitted enormously from the intensification of agriculture and the increased availability and use of synthetic fertilizers during the last century. However there has also been unintended adverse impact on the natural environment (water and ecosystems) with nitrate the most significant cause of water pollution and ecosystem damage . Many countries have introduced controls on nitrate, e.g. the European Union's Water Framework and Nitrate Directives, but despite this are continuing to see a serious decline in water quality. The purpose of our research is to investigate and quantify the importance of the unsaturated (vadose) zone pathway and groundwater in contributing to the decline. Understanding nutrient behaviour in the sub-surface environment and, in particular, the time lag between action and improvement is critical to effective management and remediation of nutrient pollution. A readily-transferable process-based model has been used to predict temporal loading of nitrate at the water table across the UK. A time-varying nitrate input function has been developed based on nitrate usage since 1925. Depth to the water table has been calculated from groundwater levels based on regional-scale observations in-filled by interpolated river base levels and vertical unsaturated zone velocities estimated from hydrogeological properties and mapping. The model has been validated using the results of more than 300 unsaturated zone nitrate profiles. Results show that for about 60% of the Chalk - the principal aquifer in the UK - peak nitrate input has yet to reach the water table and concentrations will continue to rise over the next 60 years. The implications are hugely significant especially where environmental objectives must be achieved in much shorter timescales. Current environmental and regulatory management strategies rarely take lag times into account and as a result will be poorly informed, leading to inappropriate controls and conflicts

Supporting UK adaptation: building services for the next set of UK climate projections

NASA Astrophysics Data System (ADS)

Fung, Fai; Lowe, Jason

2016-04-01

As part of the Climate Change Act 2008, the UK Government sets out a national adaptation programme to address the risks and opportunities identified in a national climate change risk assessment (CCRA) every five years. The last risk assessment in 2012 was based on the probabilistic projections for the UK published in 2009 (UKCP09). The second risk assessment will also use information from UKCP09 alongside other evidence on climate projections. However, developments in the science of climate projeciton, and evolving user needs (based partly on what has been learnt about the diverse user requirements of the UK adaptation community from the seven years of delivering and managing UKCP09 products, market research and the peer-reviewed literature) suggest now is an appropriate time to update the projections and how they are delivered. A new set of UK climate projections are now being produced to upgrade UKCP09 to reflect the latest developments in climate science, the first phase of which will be delivered in 2018 to support the third CCRA. A major component of the work is the building of a tailored service to support users of the new projections during their development and to involve users in key decisions so that the projections are of most use. We will set out the plan for the new climate projections that seek to address the evolving user need. We will also present a framework which aims to (i) facilitate the dialogue between users, boundary organisations and producers, reflecting their different decision-making roles (ii) produce scientifically robust, user-relevant climate information (iii) provide the building blocks for developing further climate services to support adaptation activities in the UK.

Reconstruction of Last Glacial Tropical SST Anomalies from Mg/Ca and UK37' to Constrain Climate Sensitivity

NASA Astrophysics Data System (ADS)

Lea, D. W.; de Garidel-Thoron, T.; Bard, E. G.; Kienast, M.

2016-12-01

Proxy paleoclimate data provides an important constrain on climate sensitivity. The tropics have been identified as a region which primarily responds to greenhouse gas forcing (GHF). The SENSETROP (Sensitivity of the Tropics) group has identified the LGM, HS1 and HS2 as key time windows to test the hypothesis that SST anomalies recorded by two geochemical paleothermometers, Mg/Ca and UK37', can be used to establish tropical climate response and, via the magnitude and spatial pattern of these anomalies, provide robust comparisons to the output of general circulation models. This work is a logical extension of prior efforts such as CLIMAP and MARGO, which largely relied on faunal SST proxies that are affected by other factors such as productivity or water column structure. With this goal in mind we have developed the SENSETROP database of published and unpublished Mg/Ca and UK37' data from low latitude (30° N to 30° S) marine cores spanning the last glacial cycle. The database contains 78 Mg/Ca records and 40 UK37' records, distributed between the tropical ocean basins: 49 in the Pacific Ocean, 32 in the Indian Ocean, and 27 in the Atlantic Ocean. Most of the cores are confined to the ocean margins. All of the data come from well dated records that include radiocarbon. As a test of the database, we determined the average SST anomaly during the LGM, 19,000-23,000 yr BP, relative to the late Holocene, 0-4,000 yr BP, from select records that contain at least 4 SST points in each time window for which the SDs < 0.75 °C. For G. ruber (all morphotypes) Mg/Ca, the recorded anomaly from 23 cores is -2.6 ± 0.6 °C, based on >1100 individual determinations. For UK37', the recorded anomaly for 14 cores is -2.4 ± 0.9 °C, based on >400 individual determinations. Agreement between these two independent proxies increases confidence in the LGM cooling level. The new results from the SENSETROP database show a strong level of homogeneity throughout the tropics, with slightly ( 0

Durability of viral suppression with first-line antiretroviral therapy in patients with HIV in the UK: an observational cohort study.

PubMed

O'Connor, Jemma; Smith, Colette; Lampe, Fiona C; Johnson, Margaret A; Chadwick, David R; Nelson, Mark; Dunn, David; Winston, Alan; Post, Frank A; Sabin, Caroline; Phillips, Andrew N

2017-07-01

The length of time that people with HIV on antiretroviral therapy (ART) with viral load suppression will be able to continue before developing viral rebound is unknown. We aimed to investigate the rate of first viral rebound in people that have achieved initial suppression with ART, to determine factors associated with viral rebound, and to use these estimates to predict long-term durability of viral suppression. The UK Collaborative HIV Cohort (UK CHIC) Study is an ongoing multicentre cohort study that brings together in a standardised format data on people with HIV attending clinics around the UK. We included participants who started ART with three or more drugs and who had achieved viral suppression (≤50 copies per mL) by 9 months after the start of ART (baseline). Viral rebound was defined as the first single viral load of more than 200 copies per mL or treatment interruption (for ≥1 month). We investigated factors associated with viral rebound with Poisson regression. These results were used to calculate the rate of viral rebound according to several key factors, including age, calendar year at start of ART, and time since baseline. Of the 16 101 people included, 4519 had a first viral rebound over 58 038 person-years (7·8 per 100 person-years, 95% CI 7·6-8·0). Of the 4519 viral rebounds, 3105 (69%) were defined by measurement of a single viral load of more than 200 copies per mL, and 1414 (31%) by a documented treatment interruption. The rate of first viral rebound declined substantially over time until 7 years from baseline. The other factors associated with viral rebound were current age at follow-up and calendar year at ART initiation (p<0·0001) and HIV risk group (p<0·0001); higher pre-ART CD4 count (p=0·0008) and pre-ART viral load (p=0·0003) were associated with viral rebound in the multivariate analysis only. For 1322 (29%) of the 3105 people with observed viral rebound, the next viral load value after rebound was 50 copies per mL or

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.

Neutronics Analysis of Water-Cooled Ceramic Breeder Blanket for CFETR

NASA Astrophysics Data System (ADS)

Zhu, Qingjun; Li, Jia; Liu, Songlin

2016-07-01

In order to investigate the nuclear response to the water-cooled ceramic breeder blanket models for CFETR, a detailed 3D neutronics model with 22.5° torus sector was developed based on the integrated geometry of CFETR, including heterogeneous WCCB blanket models, shield, divertor, vacuum vessel, toroidal and poloidal magnets, and ports. Using the Monte Carlo N-Particle Transport Code MCNP5 and IAEA Fusion Evaluated Nuclear Data Library FENDL2.1, the neutronics analyses were performed. The neutron wall loading, tritium breeding ratio, the nuclear heating, neutron-induced atomic displacement damage, and gas production were determined. The results indicate that the global TBR of no less than 1.2 will be a big challenge for the water-cooled ceramic breeder blanket for CFETR. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB108004, 2014GB122000, and 2014GB119000), and National Natural Science Foundation of China (No. 11175207)

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.

Impact of Paint Color on Rest Period Climate Control Loads in Long-Haul Trucks: Preprint

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

Lustbader, J.; Kreutzer, C.; Jeffers, M.

Cab climate conditioning is one of the primary reasons for operating the main engine in a long-haul truck during driver rest periods. In the United States, sleeper cab trucks use approximately 667 million gallons of fuel annually for rest period idling. The U.S. Department of Energy's National Renewable Energy Laboratory's (NREL) CoolCab Project works closely with industry to design efficient thermal management systems for long-haul trucks that minimize engine idling and fuel use while maintaining occupant comfort. Heat transfer to the vehicle interior from opaque exterior surfaces is one of the major heat pathways that contribute to air conditioning loadsmore » during long-haul truck daytime rest period idling. To quantify the impact of paint color and the opportunity for advanced paints, NREL collaborated with Volvo Group North America, PPG Industries, and Dometic Environmental Corporation. Initial screening simulations using CoolCalc, NREL's rapid HVAC load estimation tool, showed promising air-conditioning load reductions due to paint color selection. Tests conducted at NREL's Vehicle Testing and Integration Facility using long-haul truck cab sections, 'test bucks,' showed a 31.1% of maximum possible reduction in rise over ambient temperature and a 20.8% reduction in daily electric air conditioning energy use by switching from black to white paint. Additionally, changing from blue to an advanced color-matched solar reflective blue paint resulted in a 7.3% reduction in daily electric air conditioning energy use for weather conditions tested in Colorado. National-level modeling results using weather data from major U.S. cities indicated that the increase in heating loads due to lighter paint colors is much smaller than the reduction in cooling loads.« less

Study of a fail-safe abort system for an actively cooled hypersonic aircraft. Volume 1: Technical summary

NASA Technical Reports Server (NTRS)

Pirello, C. J.; Herring, R. L.

1976-01-01

Conceptual designs of a fail-safe abort system for hydrogen fueled actively cooled high speed aircraft are examined. The fail-safe concept depends on basically three factors: (1) a reliable method of detecting a failure or malfunction in the active cooling system, (2) the optimization of abort trajectories which minimize the descent heat load to the aircraft, and (3) fail-safe thermostructural concepts to minimize both the weight and the maximum temperature the structure will reach during descent. These factors are examined and promising approaches are evaluated based on weight, reliability, ease of manufacture and cost.

Calibration system with cryogenically-cooled loads for cosmic microwave background polarization detectors.

PubMed

Hasegawa, M; Tajima, O; Chinone, Y; Hazumi, M; Ishidoshiro, K; Nagai, M

2011-05-01

We present a novel system to calibrate millimeter-wave polarimeters for cosmic microwave background (CMB) polarization measurements. This technique is an extension of the conventional metal mirror rotation approach, however, it employs cryogenically-cooled blackbody absorbers. The primary advantage of this system is that it can generate a slightly polarized signal (∼100 mK) in the laboratory; this is at a similar level to that measured by ground-based CMB polarization experiments observing a ∼10 K sky. It is important to reproduce the observing condition in the laboratory for reliable characterization of polarimeters before deployment. In this paper, we present the design and principle of the system and demonstrate its use with a coherent-type polarimeter used for an actual CMB polarization experiment. This technique can also be applied to incoherent-type polarimeters and it is very promising for the next-generation CMB polarization experiments.

Experimental investigations on active cooling thermal protection structure of hydrocarbon-fueled scramjet combustor in arc heated facility

NASA Astrophysics Data System (ADS)

Jianqiang, Tu; Jinlong, Peng; Xianning, Yang; Lianzhong, Chen

2016-10-01

The active cooling thermal protection technology is the efficient method to resolve the long-duration work and reusable problems of hydrocarbon-fueled scramjet combustor, where worst thermo-mechanical loads occur. The fuel is passed through coolant channels adjacent to the heated surfaces to absorb heat from the heating exchanger panels, prior to injection into the combustor. The heating exchanger both cooled down the wall temperature of the combustor wall and heats and cracks the hydrocarbon fuel inside the panel to permit an easier combustion and satisfying combustion efficiency. The subscale active cooling metallic panels, with dimensions of 100×100 mm and different coolant channel sizes, have been tested under typical combustion thermal environment produced by arc heated Turbulent Flow Duct (TFD). The heat exchange ability of different coolant channel sizes has been obtained. The big-scale active cooling metallic panel, with dimensions of 100 × 750 mm and the coolant channel sizes of better heating exchange performance, has been made and tested in the big-scale arc heated TFD facility. The test results show that the local superheated ablation is easy to happen for the cooling fuel assigned asymmetrically in the bigscale active cooling metallic panel, and the cooling fuel rate can reduce 8%˜10% after spraying the Thermal Barrier Coating (TBC) in the heating surface.

One of possible variants of the organization for recycling lubricate cooling of technological means for small businesses

NASA Astrophysics Data System (ADS)

Rusica, I.; Toca, A.; Stingaci, I.; Scaticailov, S.; Scaticailov, I.; Marinescu, O.; Kosenko, P.

2016-11-01

In the paper we analyze the application lubricate cooling technological environment in the processing of various materials in the past century greatly have increased cutting speed and respectively, has increased productivity [1]. Today, none of production in which anyway is used metal cutting machines of all types (milling, turning, grinding, drilling, etc.) is not without lubricant cooling technological liquid which in turn are designed to reduce cutting force and the load on metal cutting machine tools and machined parts in order to increase durability machine tools and reduce errors of processing details and also in resource energy saving. When using lubricate cooling technological environment reduces the temperature in the cutting zone resulting in higher tool life and the preservation of the surface structure being treated reducing wear of metal parts of the machine. Typically, lubricant cooling process fluids is used without replacing as long as possible not yet beginning to negatively affect the quality of process. However life expectancy lubricate cooling technological environment is limited. According to existing normative acts every kind of lubricate cooling technological environment through certain time must be deleted by from the system and subjected to a recycling. Lubricate cooling technological environment must be disposed of for the following reasons: occurs the microbial and the mechanical pollution cutting fluid, free oil impairs operational characteristics cutting fluid and increases consumption.

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.

The medline UK filter: development and validation of a geographic search filter to retrieve research about the UK from OVID medline.

PubMed

Ayiku, Lynda; Levay, Paul; Hudson, Tom; Craven, Jenny; Barrett, Elizabeth; Finnegan, Amy; Adams, Rachel

2017-07-13

A validated geographic search filter for the retrieval of research about the United Kingdom (UK) from bibliographic databases had not previously been published. To develop and validate a geographic search filter to retrieve research about the UK from OVID medline with high recall and precision. Three gold standard sets of references were generated using the relative recall method. The sets contained references to studies about the UK which had informed National Institute for Health and Care Excellence (NICE) guidance. The first and second sets were used to develop and refine the medline UK filter. The third set was used to validate the filter. Recall, precision and number-needed-to-read (NNR) were calculated using a case study. The validated medline UK filter demonstrated 87.6% relative recall against the third gold standard set. In the case study, the medline UK filter demonstrated 100% recall, 11.4% precision and a NNR of nine. A validated geographic search filter to retrieve research about the UK with high recall and precision has been developed. The medline UK filter can be applied to systematic literature searches in OVID medline for topics with a UK focus. © 2017 Crown copyright. Health Information and Libraries Journal © 2017 Health Libraries GroupThis article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

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.

Heat-driven liquid metal cooling device for the thermal management of a computer chip

NASA Astrophysics Data System (ADS)

Ma, Kun-Quan; Liu, Jing

2007-08-01

The tremendous heat generated in a computer chip or very large scale integrated circuit raises many challenging issues to be solved. Recently, liquid metal with a low melting point was established as the most conductive coolant for efficiently cooling the computer chip. Here, by making full use of the double merits of the liquid metal, i.e. superior heat transfer performance and electromagnetically drivable ability, we demonstrate for the first time the liquid-cooling concept for the thermal management of a computer chip using waste heat to power the thermoelectric generator (TEG) and thus the flow of the liquid metal. Such a device consumes no external net energy, which warrants it a self-supporting and completely silent liquid-cooling module. Experiments on devices driven by one or two stage TEGs indicate that a dramatic temperature drop on the simulating chip has been realized without the aid of any fans. The higher the heat load, the larger will be the temperature decrease caused by the cooling device. Further, the two TEGs will generate a larger current if a copper plate is sandwiched between them to enhance heat dissipation there. This new method is expected to be significant in future thermal management of a desk or notebook computer, where both efficient cooling and extremely low energy consumption are of major concern.

Cooling of Gas Turbines. 2; Effectiveness of Rim Cooling of Blades

NASA Technical Reports Server (NTRS)

Wolfenstein, Lincoln; Meyer, Gene L.; McCarthy, John S.

1947-01-01

An analysis is presented of rim cooling of gas-turbine blades; that is, reducing the temperature at the base of the blade (wheel rim), which cools the blade by conduction alone. Formulas for temperature and stress distributions along the blade are derived and, by the use of experimental stress-rupture data for a typical blade alloy, a relation is established between blade life (time for rupture), operating speed, and amount of rim cooling for several gas temperatures. The effect of blade parameter combining the effects of blade dimensions, blade thermal conductivity, and heat-transfer coefficient is determined. The effect of radiation on the results is approximated. The gas temperatures ranged from 1300F to 1900F and the rim temperature, from 0F to 1000F below the gas temperature. This report is concerned only with blades of uniform cross section, but the conclusions drawn are generally applicable to most modern turbine blades. For a typical rim-cooled blade, gas temperature increases are limited to about 200F for 500F of cooling of the blade base below gas temperature, and additional cooling brings progressively smaller increases. In order to obtain large increases in thermal conductivity or very large decreases in heat-transfer coefficient or blade length or necessary. The increases in gas temperature allowable with rim cooling are particularly small for turbines of large dimensions and high specific mass flows. For a given effective gas temperature, substantial increases in blade life, however, are possible with relatively small amounts of rim cooling.

Numerical and Experimental Investigation on the Performance of a Thermoelectric Cooling Automotive Seat

NASA Astrophysics Data System (ADS)

Su, Chuqi; Dong, Wenbin; Deng, Yadong; Wang, Yiping; Liu, Xun

2017-11-01

Heating, ventilating and air conditioning (HVAC) is the most significant auxiliary load in vehicles and largely increases extra emissions. Therefore, thermoelectric cooling automotive seat, a relatively new technology, is used in an attempt to reduce HVAC consumption and improve thermal comfort. In this study, three design schemes of the thermoelectric cooler (TEC) are proposed. Then the numerical simulation is used to analyze their heat transfer performance, and evaluate the improvement of the seat cooling in terms of the occupant back thermal comfort. Moreover, an experiment is conducted to validate the accuracy of the simulation results. The experimental results show that: (1) an average reduction in air temperature of 4°C in 60 s is obtained; (2) the temperature of the occupant's back drops from 33.5°C to 25.7°C in cooperation with the HVAC system; (3) back thermal comfort is greatly improved. As expected, the thermoelectric cooling automotive seat is able to provide an improvement in the occupant's thermal comfort at a reduced energy consumption rate, which makes it promising for vehicular application.

Numerical and Experimental Investigation on the Performance of a Thermoelectric Cooling Automotive Seat

NASA Astrophysics Data System (ADS)

Su, Chuqi; Dong, Wenbin; Deng, Yadong; Wang, Yiping; Liu, Xun

2018-06-01

Heating, ventilating and air conditioning (HVAC) is the most significant auxiliary load in vehicles and largely increases extra emissions. Therefore, thermoelectric cooling automotive seat, a relatively new technology, is used in an attempt to reduce HVAC consumption and improve thermal comfort. In this study, three design schemes of the thermoelectric cooler (TEC) are proposed. Then the numerical simulation is used to analyze their heat transfer performance, and evaluate the improvement of the seat cooling in terms of the occupant back thermal comfort. Moreover, an experiment is conducted to validate the accuracy of the simulation results. The experimental results show that: (1) an average reduction in air temperature of 4°C in 60 s is obtained; (2) the temperature of the occupant's back drops from 33.5°C to 25.7°C in cooperation with the HVAC system; (3) back thermal comfort is greatly improved. As expected, the thermoelectric cooling automotive seat is able to provide an improvement in the occupant's thermal comfort at a reduced energy consumption rate, which makes it promising for vehicular application.

Performative building envelope design correlated to solar radiation and cooling energy consumption

NASA Astrophysics Data System (ADS)

Jacky, Thiodore; Santoni

2017-11-01

Climate change as an ongoing anthropogenic environmental challenge is predominantly caused by an amplification in the amount of greenhouse gases (GHGs), notably carbon dioxide (CO2) in building sector. Global CO2 emissions are emitted from HVAC (Heating, Ventilation, and Air Conditioning) occupation to provide thermal comfort in building. In fact, the amount of energy used for cooling or heating building is implication of building envelope design. Building envelope acts as interface layer of heat transfer between outdoor environment and the interior of a building. It appears as wall, window, roof and external shading device. This paper examines performance of various design strategy on building envelope to limit solar radiation and reduce cooling loads in tropical climate. The design strategies are considering orientation, window to wall ratio, material properties, and external shading device. This research applied simulation method using Autodesk Ecotect to investigate simultaneously between variations of wall and window ratio, shading device composition and the implication to the amount of solar radiation, cooling energy consumption. Comparative analysis on the data will determine logical variation between opening and shading device composition and cooling energy consumption. Optimizing the building envelope design is crucial strategy for reducing CO2 emissions and long-term energy reduction in building sector. Simulation technology as feedback loop will lead to better performative building envelope.

The Geomatics.org.UK Project

ERIC Educational Resources Information Center

Bramald, Tom; Powell, Jonathan

2006-01-01

In this article, the authors describe how pupils can benefit from some unusual and exciting free resources of geomatics.org.uk. Geomatics.org.uk is a project that provides free resources to support teaching and learning in a variety of subjects including maths and geography, often in a cross-curricular way. Via the project website, it is possible,…

The analysis of the process in the cooling tower with the low efficiency

NASA Astrophysics Data System (ADS)

Badriev, A. I.; Sharifullin, V. N.

2017-11-01

We put quite a difficult task maintaining a temperature drop to 11-12 degrees at thermal power plants to ensure the required depth of cooling of vacuum in the condenser, cooling towers. This requirement is achieved with the reducing of the hydraulic load with the low efficiency of the apparatus. The task analysis process in this unit and identify the causes of his poor performance was put in the work. One of the possible reasons may be the heterogeneity of the process in the volume of the apparatus. Therefore, it was decided to investigate experimentally the distribution of the irrigation water and the air flow in the cross section of industrial cooling towers. As a result, we found a significant uneven distribution of flows of water and air in the volume of the apparatus. We have shown theoretically that the uneven distribution of irrigation leads to a significant decrease in the efficiency of evaporation in the cooling tower. The velocity distribution of the air as the tower sections, and inside sections are interesting. The obtained experimental data allowed to establish the internal communication: the effects of the distributions of the density of irrigation in sections of the apparatus for the distribution of changes of the temperature and the air velocity. The obtained results allowed to formulate a methodology for determining process problems and to develop actions on increase of the efficiency of the cooling tower.

Simulation of plasma loading of high-pressure RF cavities

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

Yu, K.; Samulyak, R.; Yonehara, K.

2018-01-11

Muon beam-induced plasma loading of radio-frequency (RF) cavities filled with high pressure hydrogen gas with 1% dry air dopant has been studied via numerical simulations. The electromagnetic code SPACE, that resolves relevant atomic physics processes, including ionization by the muon beam, electron attachment to dopant molecules, and electron-ion and ion-ion recombination, has been used. Simulations studies have also been performed in the range of parameters typical for practical muon cooling channels.

Simulation of plasma loading of high-pressure RF cavities

NASA Astrophysics Data System (ADS)

Yu, K.; Samulyak, R.; Yonehara, K.; Freemire, B.

2018-01-01

Muon beam-induced plasma loading of radio-frequency (RF) cavities filled with high pressure hydrogen gas with 1% dry air dopant has been studied via numerical simulations. The electromagnetic code SPACE, that resolves relevant atomic physics processes, including ionization by the muon beam, electron attachment to dopant molecules, and electron-ion and ion-ion recombination, has been used. Simulations studies have been performed in the range of parameters typical for practical muon cooling channels.

The Pawsey Supercomputer geothermal cooling project

NASA Astrophysics Data System (ADS)

Regenauer-Lieb, K.; Horowitz, F.; Western Australian Geothermal Centre Of Excellence, T.

2010-12-01

The Australian Government has funded the Pawsey supercomputer in Perth, Western Australia, providing computational infrastructure intended to support the future operations of the Australian Square Kilometre Array radiotelescope and to boost next-generation computational geosciences in Australia. Supplementary funds have been directed to the development of a geothermal exploration well to research the potential for direct heat use applications at the Pawsey Centre site. Cooling the Pawsey supercomputer may be achieved by geothermal heat exchange rather than by conventional electrical power cooling, thus reducing the carbon footprint of the Pawsey Centre and demonstrating an innovative green technology that is widely applicable in industry and urban centres across the world. The exploration well is scheduled to be completed in 2013, with drilling due to commence in the third quarter of 2011. One year is allocated to finalizing the design of the exploration, monitoring and research well. Success in the geothermal exploration and research program will result in an industrial-scale geothermal cooling facility at the Pawsey Centre, and will provide a world-class student training environment in geothermal energy systems. A similar system is partially funded and in advanced planning to provide base-load air-conditioning for the main campus of the University of Western Australia. Both systems are expected to draw ~80-95 degrees C water from aquifers lying between 2000 and 3000 meters depth from naturally permeable rocks of the Perth sedimentary basin. The geothermal water will be run through absorption chilling devices, which only require heat (as opposed to mechanical work) to power a chilled water stream adequate to meet the cooling requirements. Once the heat has been removed from the geothermal water, licensing issues require the water to be re-injected back into the aquifer system. These systems are intended to demonstrate the feasibility of powering large-scale air

Turbomachine rotor with improved cooling

DOEpatents

Hultgren, Kent Goran; McLaurin, Leroy Dixon; Bertsch, Oran Leroy; Lowe, Perry Eugene

1998-01-01

A gas turbine rotor has an essentially closed loop cooling air scheme in which cooling air drawn from the compressor discharge air that is supplied to the combustion chamber is further compressed, cooled, and then directed to the aft end of the turbine rotor. Downstream seal rings attached to the downstream face of each rotor disc direct the cooling air over the downstream disc face, thereby cooling it, and then to cooling air passages formed in the rotating blades. Upstream seal rings attached to the upstream face of each disc direct the heated cooling air away from the blade root while keeping the disc thermally isolated from the heated cooling air. From each upstream seal ring, the heated cooling air flows through passages in the upstream discs and is then combined and returned to the combustion chamber from which it was drawn.

Innovative discharge geometries for diffusion-cooled gas lasers

NASA Astrophysics Data System (ADS)

Lapucci, Antonio

2004-09-01

Large area, narrow discharge gap, diffusion cooled gas lasers are nowadays a well established technology for the construction of industrial laser sources. Successful examples exist both with the slab (Rofin-Sinar) or coaxial (Trumpf) geometry. The main physical properties and the associated technical problems of the transverse large area RF discharge, adopted for the excitation of high power diffusion cooled gas lasers, are reviewed here. The main problems of this technology are related to the maintenance of a uniform and stable plasma excitation between closely spaced large-area electrodes at high power-density loading. Some practical solutions such as distributed resonance of the discharge channel proved successful in the case of square or rectangular cross-sections but hardly applicable to geometries such as that of coaxial electrodes. In this paper we present some solutions, adopted by our group, for the development of slab and annular CO2 lasers and for CO2 laser arrays with linear or circular symmetry. We will also briefly mention the difficulties encountered in the extraction of a good quality beam from an active medium with such a cross section. A problem that has also seen some interesting solutions.

Passive cooling and heating program at Oak Ridge National Laboratory for FY-1981

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

Shapira, H.B.; Kaplan, S.I.; Chester, C.V.

1981-01-01

Construction was completed of an earth-sheltered, passively solar heated office-dormitory, the Joint Institute for Heavy Ion Research, designed at ORNL. Instrumentation of the building was designed, procured, and installed. Building performance will be monitored and compared with predictions of the DOE-2 code. A study of the incorporation of vegetation on architecture was conducted by the Harvard School of Design. A final report was issued which is a prototype handbook for the use of vegetation to reduce cooling loads in structures. An experiment to reduce the cooling requirement of mobile homes by shading with fast-growing vines was begun: a maintenance-oriented trellismore » was constructed and vines were planted. An RFP for the production of a prototype set of reflective insulating blinds was issued.« less

Design of a low parasitic inductance SiC power module with double-sided cooling

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

Yang, Fei; Liang, Zhenxian; Wang, Fei

In this paper, a low-parasitic inductance SiC power module with double-sided cooling is designed and compared with a baseline double-sided cooled module. With the unique 3D layout utilizing vertical interconnection, the power loop inductance is effectively reduced without sacrificing the thermal performance. Both simulations and experiments are carried out to validate the design. Q3D simulation results show a power loop inductance of 1.63 nH, verified by the experiment, indicating more than 60% reduction of power loop inductance compared with the baseline module. With 0Ω external gate resistance turn-off at 600V, the voltage overshoot is less than 9% of the busmore » voltage at a load of 44.6A.« less

Gas turbine cooling system

DOEpatents

Bancalari, Eduardo E.

2001-01-01

A gas turbine engine (10) having a closed-loop cooling circuit (39) for transferring heat from the hot turbine section (16) to the compressed air (24) produced by the compressor section (12). The closed-loop cooling system (39) includes a heat exchanger (40) disposed in the flow path of the compressed air (24) between the outlet of the compressor section (12) and the inlet of the combustor (14). A cooling fluid (50) may be driven by a pump (52) located outside of the engine casing (53) or a pump (54) mounted on the rotor shaft (17). The cooling circuit (39) may include an orifice (60) for causing the cooling fluid (50) to change from a liquid state to a gaseous state, thereby increasing the heat transfer capacity of the cooling circuit (39).

Development of SMA Actuated Morphing Airfoil for Wind Turbine Load Alleviation

NASA Astrophysics Data System (ADS)

Karakalas, A.; Machairas, T.; Solomou, A.; Riziotis, V.; Saravanos, D.

Wind turbine rotor upscaling has entered a range of rotor diameters where the blade structure cannot sustain the increased aerodynamic loads without novel load alleviation concepts. Research on load alleviation using morphing blade sections is presented. Antagonistic shape memory alloy (SMA) actuators are implemented to deflect the section trailing edge (TE) to target shapes and target time-series relating TE movement with changes in lift coefficient. Challenges encountered by the complex thermomechanical response of morphing section and the enhancement of SMA transient response to achieve frequencies meaningful for aerodynamic load alleviation are addressed. Using a recently developed finite element for SMA actuators [1], actuator configurations are considered for fast cooling and heating cycles. Numerical results quantify the attained ranges of TE angle movement, the moving time period and the developed stresses. Estimations of the attained variations of lift coefficient vs. time are also presented to assess the performance of the morphing section.

Transpiring Cooling of a Scram-Jet Engine Combustion Chamber

NASA Technical Reports Server (NTRS)

Choi, Sang H.; Scotti, Stephen J.; Song, Kyo D.; Ries,Heidi

1997-01-01

The peak cold-wall heating rate generated in a combustion chamber of a scram-jet engine can exceed 2000 Btu/sq ft sec (approx. 2344 W/sq cm). Therefore, a very effective heat dissipation mechanism is required to sustain such a high heating load. This research focused on the transpiration cooling mechanism that appears to be a promising approach to remove a large amount of heat from the engine wall. The transpiration cooling mechanism has two aspects. First, initial computations suggest that there is a reduction, as much as 75%, in the heat flux incident on the combustion chamber wall due to the transpirant modifying the combustor boundary layer. Secondly, the heat reaching the combustor wall is removed from the structure in a very effective manner by the transpirant. It is the second of these two mechanisms that is investigated experimentally in the subject paper. A transpiration cooling experiment using a radiant heating method, that provided a heat flux as high as 200 Btu/sq ft sec ( approx. 234 W/sq cm) on the surface of a specimen, was performed. The experiment utilized an arc-lamp facility (60-kW radiant power output) to provide a uniform heat flux to a test specimen. For safety reasons, helium gas was used as the transpirant in the experiments. The specimens were 1.9-cm diameter sintered, powdered-stainless-steel tubes of various porosities and a 2.54cm square tube with perforated multi-layered walls. A 15-cm portion of each specimen was heated. The cooling effectivenes and efficiencies by transpiration for each specimen were obtained using the experimental results. During the testing, various test specimens displayed a choking phenomenon in which the transpirant flow was limited as the heat flux was increased. The paper includes a preliminary analysis of the transpiration cooling mechanism and a scaling conversion study that translates the results from helium tests into the case when a hydrogen medium is used.

Curved film cooling admission tube

NASA Astrophysics Data System (ADS)

Graham, R. W.; Papell, S. S.

1980-10-01

Effective film cooling to protect a wall surface from a hot fluid which impinges on or flows along the surface is provided. A film of cooling fluid having increased area is provided by changing the direction of a stream of cooling fluid through an angle of from 135 deg. to 165 deg. before injecting it through the wall into the hot flowing gas. The 1, cooling fluid is injected from an orifice through a wall into a hot flowing gas at an angle to form a cooling fluid film. Cooling fluid is supplied to the orifice from a cooling fluid source via a turbulence control passageway having a curved portion between two straight portions. The angle through which the direction of the cooling fluid is turned results in less mixing of the cooling fluid with the hot gas, thereby substantially increasing the length of the film in a downstream direction.

Curved film cooling admission tube

NASA Technical Reports Server (NTRS)

Graham, R. W.; Papell, S. S. (Inventor)

1980-01-01

Effective film cooling to protect a wall surface from a hot fluid which impinges on or flows along the surface is provided. A film of cooling fluid having increased area is provided by changing the direction of a stream of cooling fluid through an angle of from 135 deg. to 165 deg. before injecting it through the wall into the hot flowing gas. The 1, cooling fluid is injected from an orifice through a wall into a hot flowing gas at an angle to form a cooling fluid film. Cooling fluid is supplied to the orifice from a cooling fluid source via a turbulence control passageway having a curved portion between two straight portions. The angle through which the direction of the cooling fluid is turned results in less mixing of the cooling fluid with the hot gas, thereby substantially increasing the length of the film in a downstream direction.

Turbomachine rotor with improved cooling

DOEpatents

Hultgren, K.G.; McLaurin, L.D.; Bertsch, O.L.; Lowe, P.E.

1998-05-26

A gas turbine rotor has an essentially closed loop cooling air scheme in which cooling air drawn from the compressor discharge air that is supplied to the combustion chamber is further compressed, cooled, and then directed to the aft end of the turbine rotor. Downstream seal rings attached to the downstream face of each rotor disc direct the cooling air over the downstream disc face, thereby cooling it, and then to cooling air passages formed in the rotating blades. Upstream seal rings attached to the upstream face of each disc direct the heated cooling air away from the blade root while keeping the disc thermally isolated from the heated cooling air. From each upstream seal ring, the heated cooling air flows through passages in the upstream discs and is then combined and returned to the combustion chamber from which it was drawn. 5 figs.

Cool Shelter

ERIC Educational Resources Information Center

Praeger, Charles E.

2005-01-01

Amid climbing energy costs and tightening budgets, administrators at school districts, colleges and universities are looking for all avenues of potential savings while promoting sustainable communities. Cool metal roofing can save schools money and promote sustainable design at the same time. Cool metal roofing keeps the sun's heat from collecting…

Experimental feasibility study of radial injection cooling of three-pad radial air foil bearings

NASA Astrophysics Data System (ADS)

Shrestha, Suman K.

referenced to the rotor surface speed for radial injection cooling. The mass flow rates for the radial injection were 0.032, 0.0432, 0.054 and 0.068 Kg/min, which result in average injection speed of 150, 200, 250 and 300% of rotor surface speed. Several thermocouples were attached at various circumferential directions of the bearing sleeve, two plenums, bearing holder and ball bearing housings to collect the temperature data of the bearing at 30krpm under 10lb of load. Both axial cooling and radial injection are effective cooling mechanism and effectiveness of both cooling methods is directly proportional to the total mass flow rates. However, axial cooling is slightly more efficient in controlling the average temperature of the bearing sleeve, but results in higher thermal gradient of the shaft along the axial direction and also higher thermal gradient of the bearing sleeve along the circumferential direction compared to the radial injection cooling. The smaller thermal gradient of the radial injection cooling is due to the direct cooling effect of the shaft by impinging jets. While the axial cooling has an effect on only the bearing, the radial injection has a cooling effect on both the bearing sleeve and shaft. It is considered the radial injection cooling needs to be further optimized in terms of number of injection holes and their locations.

High-heat-load monochromator options for the RIXS beamline at the APS with the MBA lattice

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

Liu, Zunping, E-mail: zpliu@anl.gov; Gog, Thomas, E-mail: gog@aps.anl.gov; Stoupin, Stanislav A.

2016-07-27

With the MBA lattice for APS-Upgrade, tuning curves of 2.6 cm period undulators meet the source requirements for the RIXS beamline. The high-heat-load monochromator (HHLM) is the first optical white beam component. There are four options for the HHLM such as diamond monochromators with refrigerant of either water or liquid nitrogen (LN{sub 2}), and silicon monochromators of either direct or indirect cooling system. Their performances are evaluated at energy 11.215 keV (Ir L-III edge). The cryo-cooled diamond monochromator has similar performance as the water-cooled diamond monochromator because GaIn of the Cu-GaIn-diamond interface becomes solid. The cryo-cooled silicon monochromators perform better,more » not only in terms of surface slope error due to thermal deformation, but also in terms of thermal capacity.« less

Simulation and Experimental Study of Metal Organic Frameworks Used in Adsorption Cooling

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

Jenks, Jeromy J.; Motkuri, Radha K.; TeGrotenhuis, Ward

2016-10-11

Metal-organic frameworks (MOFs) have recently attracted enormous interest over the past few years in energy storage and gas separation, yet there have been few reports for adsorption cooling applications. Adsorption cooling technology is an established alternative to mechanical vapor compression refrigeration systems and is an excellent alternative in industrial environments where waste heat is available. We explored the use of MOFs that have very high mass loading and relatively low heats of adsorption, with certain combinations of refrigerants to demonstrate a new type of highly efficient adsorption chiller. Computational fluid dynamics combined with a system level lumped-parameter model have beenmore » used to project size and performance for chillers with a cooling capacity ranging from a few kW to several thousand kW. These systems rely on stacked micro/mini-scale architectures to enhance heat and mass transfer. Recent computational studies of an adsorption chiller based on MOFs suggests that a thermally-driven coefficient of performance greater than one may be possible, which would represent a fundamental breakthrough in performance of adsorption chiller technology. Presented herein are computational and experimental results for hydrophyilic and fluorophilic MOFs.« less

Renewable Heating and Cooling

EPA Pesticide Factsheets

Find information on the benefits of renewable heating and cooling technologies that can be used in place of conventional heating and cooling technologies for common applications such as water heating, space heating, space cooling and process heat.

Cooling of gas turbines IX : cooling effects from use of ceramic coatings on water-cooled turbine blades

NASA Technical Reports Server (NTRS)

Brown, W Byron; Livingood, John N B

1948-01-01

The hottest part of a turbine blade is likely to be the trailing portion. When the blades are cooled and when water is used as the coolant, the cooling passages are placed as close as possible to the trailing edge in order to cool this portion. In some cases, however, the trailing portion of the blade is so narrow, for aerodynamic reasons, that water passages cannot be located very near the trailing edge. Because ceramic coatings offer the possibility of protection for the trailing part of such narrow blades, a theoretical study has been made of the cooling effect of a ceramic coating on: (1) the blade-metal temperature when the gas temperature is unchanged, and (2) the gas temperature when the metal temperature is unchanged. Comparison is also made between the changes in the blade or gas temperatures produced by ceramic coatings and the changes produced by moving the cooling passages nearer the trailing edge. This comparison was made to provide a standard for evaluating the gains obtainable with ceramic coatings as compared to those obtainable by constructing the turbine blade in such a manner that water passages could be located very near the trailing edge.

Renewable Heating And Cooling

EPA Pesticide Factsheets

Renewable heating and cooling is a set of alternative resources and technologies that can be used in place of conventional heating and cooling technologies for common applications such as water heating, space heating, space cooling and process heat.

Non-intrusive cooling system

DOEpatents

Morrison, Edward F.; Bergman, John W.

2001-05-22

A readily replaceable heat exchange cooling jacket for applying fluid to a system conduit pipe. The cooling jacket comprises at least two members, separable into upper and lower portions. A chamber is formed between the conduit pipe and cooling jacket once the members are positioned about the pipe. The upper portion includes a fluid spray means positioned above the pipe and the bottom portion includes a fluid removal means. The heat exchange cooling jacket is adaptable with a drain tank, a heat exchanger, a pump and other standard equipment to provide a system for removing heat from a pipe. A method to remove heat from a pipe, includes the steps of enclosing a portion of the pipe with a jacket to form a chamber between an outside surface of the pipe and the cooling jacket; spraying cooling fluid at low pressure from an upper portion of the cooling jacket, allowing the fluid to flow downwardly by gravity along the surface of the pipe toward a bottom portion of the chamber; and removing the fluid at the bottom portion of the chamber.

A Si/Glass Bulk-Micromachined Cryogenic Heat Exchanger for High Heat Loads: Fabrication, Test, and Application Results.

PubMed

Zhu, Weibin; White, Michael J; Nellis, Gregory F; Klein, Sanford A; Gianchandani, Yogesh B

2010-02-01

This paper reports on a micromachined Si/glass stack recuperative heat exchanger with in situ temperature sensors. Numerous high-conductivity silicon plates with integrated platinum resistance temperature detectors (Pt RTDs) are stacked, alternating with low-conductivity Pyrex spacers. The device has a 1 x 1-cm(2) footprint and a length of up to 3.5 cm. It is intended for use in Joule-Thomson (J-T) coolers and can sustain pressure exceeding 1 MPa. Tests at cold-end inlet temperatures of 237 K-252 K show that the heat exchanger effectiveness is 0.9 with 0.039-g/s helium mass flow rate. The integrated Pt RTDs present a linear response of 0.26%-0.30%/K over an operational range of 205 K-296 K but remain usable at lower temperatures. In self-cooling tests with ethane as the working fluid, a J-T system with the heat exchanger drops 76.1 K below the inlet temperature, achieving 218.7 K for a pressure of 835.8 kPa. The system reaches 200 K in transient state; further cooling is limited by impurities that freeze within the flow stream. In J-T self-cooling tests with an external heat load, the system reaches 239 K while providing 1 W of cooling. In all cases, there is an additional parasitic heat load estimated at 300-500 mW.

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.

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.

Performance of the supercritical helium cooling loop for the JET divertor cryopump

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

Obert, W.; Mayaux, C.; Barth, K.

1996-12-31

A supercritical helium cooling loop for the two JET divertor cryopumps has been tested, commissioned and is operational practically uninterrupted for over one year. Operation experience under a number of different boundary and transient conditions have been obtained. The flow of the supercritical helium (6 g/s, 2.7 bar) is driven by the main compressor of the JET helium refrigerator passing a heat exchanger where it is subcooled to 4.1 K before entering the two cryopumps which are an assembly of two 60 m long and 20 mm diameter corrugated stainless steel tubes. By using a dedicated cold ejector which ismore » driven by the main flow and where the expansion from 12 bar to 2.7 bar takes place increases the flow of supercritical helium up to {approximately}17 g/s. The steady state thermal load to the cooling loop of the cryopump is < 80 W but during transient conditions in particular due to nuclear heating in the active phase of JET considerably higher transient heat loads can be accepted by the loop. Details about the steady state and transient thermal conditions as well as the cooldown and warm up behavior of the loop and the interaction of the supercritical loop with the operation of other plant equipment will be discussed in the paper.« less

Paediatric home care in the UK.

PubMed Central

Tatman, M A; Woodroffe, C

1993-01-01

Paediatric home care services in the UK were ascertained in 1991 and 1992. Respondents from 209 (97%) UK health districts and boards identified 62 general and 124 specialist paediatric home care services by January 1993, 15% having opened in the previous year. Of all UK children, 30% lived in a district with a general home care service. Five health regions had only specialist services. Districts differed widely in the availability of home care for different disorders. The home care services were small, general services employing a mean (SD) of 2.5 (1.6) whole time equivalent (WTE) nurses, and specialist services 1.3 (0.8) WTE nurses. Few services were available 24 hours a day. Funding arrangements were diverse and some services had difficulties in obtaining consumables and equipment for home use. Despite rapid growth there remains considerable scope for the development of paediatric home care throughout the UK. PMID:8285782

Transformation-Induced Diffraction Peak Broadening During Bainitic and Martensitic Transformations Under Small External Loads in a Quenched and Tempered High Strength Steel

NASA Astrophysics Data System (ADS)

Dutta, R. K.; Huizenga, R. M.; Amirthalingam, M.; Hermans, M. J. M.; King, A.; Richardson, I. M.

2013-09-01

In situ phase transformation behavior of a high strength S690QL1 steel during continuous cooling under different mechanical loading conditions has been used to investigate the effect of small external loads on the transformation-induced plasticity during bainitic and martensitic transformations. The results show that during phase transformations, the untransformed austenite undergoes plastic deformation, thereby retarding further transformation to bainite/martensite. This occurs independent of external load.

The Returns to UK Degrees for Foreign-Educated Graduates

ERIC Educational Resources Information Center

Valbuena, Javier; Zhu, Yu

2018-01-01

Exploiting information on foreign qualifications for the first time, we estimate the returns to obtaining UK higher degrees for foreign graduates who migrated to the UK in their 20s. Accounting for direct measures of foreign and UK qualifications and country-of-origin fixed effects, we find substantial returns to obtaining UK (higher) degrees on…

Data-based mechanistic modeling of dissolved organic carbon load through storms using continuous 15-minute resolution observations within UK upland watersheds

NASA Astrophysics Data System (ADS)

Jones, T.; Chappell, N. A.

2013-12-01

Few watershed modeling studies have addressed DOC dynamics through storm hydrographs (notable exceptions include Boyer et al., 1997 Hydrol Process; Jutras et al., 2011 Ecol Model; Xu et al., 2012 Water Resour Res). In part this has been a consequence of an incomplete understanding of the biogeochemical processes leading to DOC export to streams (Neff & Asner, 2001, Ecosystems) & an insufficient frequency of DOC monitoring to capture sometimes complex time-varying relationships between DOC & storm hydrographs (Kirchner et al., 2004, Hydrol Process). We present the results of a new & ongoing UK study that integrates two components - 1/ New observations of DOC concentrations (& derived load) continuously monitored at 15 minute intervals through multiple seasons for replicated watersheds; & 2/ A dynamic modeling technique that is able to quantify storage-decay effects, plus hysteretic, nonlinear, lagged & non-stationary relationships between DOC & controlling variables (including rainfall, streamflow, temperature & specific biogeochemical variables e.g., pH, nitrate). DOC concentration is being monitored continuously using the latest generation of UV spectrophotometers (i.e. S::CAN spectro::lysers) with in situ calibrations to laboratory analyzed DOC. The controlling variables are recorded simultaneously at the same stream stations. The watersheds selected for study are among the most intensively studied basins in the UK uplands, namely the Plynlimon & Llyn Brianne experimental basins. All contain areas of organic soils, with three having improved grasslands & three conifer afforested. The dynamic response characteristics (DRCs) that describe detailed DOC behaviour through sequences of storms are simulated using the latest identification routines for continuous time transfer function (CT-TF) models within the Matlab-based CAPTAIN toolbox (some incorporating nonlinear components). To our knowledge this is the first application of CT-TFs to modelling DOC processes

Laser cooling of molecular anions.

PubMed

Yzombard, Pauline; Hamamda, Mehdi; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

2015-05-29

We propose a scheme for laser cooling of negatively charged molecules. We briefly summarize the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C_{2}^{-}, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photodetachment process is present, as well as Doppler laser cooling of trapped C_{2}^{-}, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources, and antimatter physics.

Cooled railplug

DOEpatents

Weldon, W.F.

1996-05-07

The railplug is a plasma ignitor capable of injecting a high energy plasma jet into a combustion chamber of an internal combustion engine or continuous combustion system. An improved railplug is provided which has dual coaxial chambers (either internal or external to the center electrode) that provide for forced convective cooling of the electrodes using the normal pressure changes occurring in an internal combustion engine. This convective cooling reduces the temperature of the hot spot associated with the plasma initiation point, particularly in coaxial railplug configurations, and extends the useful life of the railplug. The convective cooling technique may also be employed in a railplug having parallel dual rails using dual, coaxial chambers. 10 figs.

Cooling Vest

NASA Technical Reports Server (NTRS)

1983-01-01

Because quadriplegics are unable to perspire below the level of spinal injury, they cannot tolerate heat stress. A cooling vest developed by Ames Research Center and Upjohn Company allows them to participate in outdoor activities. The vest is an adaptation of Ames technology for thermal control garments used to remove excess body heat of astronauts. The vest consists of a series of corrugated channels through which cooled water circulates. Its two outer layers are urethane coated nylon, and there is an inner layer which incorporates the corrugated channels. It can be worn as a backpack or affixed to a wheelchair. The unit includes a rechargeable battery, mini-pump, two quart reservoir and heat sink to cool the water.

Cooled railplug

DOEpatents

Weldon, William F.

1996-01-01

The railplug is a plasma ignitor capable of injecting a high energy plasma jet into a combustion chamber of an internal combustion engine or continuous combustion system. An improved railplug is provided which has dual coaxial chambers (either internal or external to the center electrode) that provide for forced convective cooling of the electrodes using the normal pressure changes occurring in an internal combustion engine. This convective cooling reduces the temperature of the hot spot associated with the plasma initiation point, particularly in coaxial railplug configurations, and extends the useful life of the railplug. The convective cooling technique may also be employed in a railplug having parallel dual rails using dual, coaxial chambers.

Nutrient cycles in agricultural systems at sub-catchment scale within the UK and China

NASA Astrophysics Data System (ADS)

Bellarby, Jessica; Surridge, Ben; Haygarth, Philip M.; Lai, Xin; Zhang, Guilong; Song, Xiaolong; Zhou, Jianbin; Meng, Fanqiao; Shen, Jianbo; Rahn, Clive; Smith, Laurence; Burke, Sean

2015-04-01

Diffuse water pollution from agriculture (DWPA) represents a significant challenge in both the UK and China. The UK has developed policies and practices which seek to mitigate DWPA, yet the risks and adverse impacts of DWPA remain widespread. In contrast, China's past priorities have largely focussed on food security, with an emphasis on increasing food production through high fertiliser application rates with little attention being paid to enhanced nutrient export from land to water and to air. This has contributed to severe environmental problems which are only now beginning to be recognised and addressed. We have prepared nutrient balances (phosphorus and nitrogen) in contrasting agricultural production systems at sub-catchment scale within China and the UK. These draw from a variety of sources ranging from general yearly statistics collected by the respective government to farm surveys. Our aim is to use the resulting nutrient balances to underpin the sharing of knowledge and innovation to mitigate DWPA in both nations. In the UK, the case studies focus on the three Demonstration Test Catchment locations, covering a range of livestock and arable production systems across England. Here, the high frequency monitoring of phosphorus river loads enables the cross-validation of the simple nutrient budget approaches applied in this study. In China, our case studies span kiwi orchard, fruit and vegetable solar greenhouse systems, double cropped rice-wheat and wheat-maize production systems. Substantial differences in nutrient stocks and flows exist between individual production systems both across and within the two countries. These differences will be expressed along the source-mobilisation-delivery-impact continuum that underpins our budgets for both phosphorus and nitrogen. We will present the phosphorus cycles of some case studies and highlight their challenges and relevance at sub-catchment scale. Based on our nutrient budgets, general recommendations can be

Stacking with stochastic cooling

NASA Astrophysics Data System (ADS)

Caspers, Fritz; Möhl, Dieter

2004-10-01

Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 105 the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some considerations to the 'azimuthal' schemes.

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

Testing and Optimizing a Stove-Powered Thermoelectric Generator with Fan Cooling.

PubMed

Zheng, Youqu; Hu, Jiangen; Li, Guoneng; Zhu, Lingyun; Guo, Wenwen

2018-06-07

In order to provide heat and electricity under emergency conditions in off-grid areas, a stove-powered thermoelectric generator (STEG) was designed and optimized. No battery was incorporated, ensuring it would work anytime, anywhere, as long as combustible materials were provided. The startup performance, power load feature and thermoelectric (TE) efficiency were investigated in detail. Furthermore, the heat-conducting plate thickness, cooling fan selection, heat sink dimension and TE module configuration were optimized. The heat flow method was employed to determine the TE efficiency, which was compared to the predicted data. Results showed that the STEG can supply clean-and-warm air (625 W) and electricity (8.25 W at 5 V) continuously at a temperature difference of 148 °C, and the corresponding TE efficiency was measured to be 2.31%. Optimization showed that the choice of heat-conducting plate thickness, heat sink dimensions and cooling fan were inter-dependent, and the TE module configuration affected both the startup process and the power output.

Toward Cooling Uniformity: Investigation of Spiral, Sweeping Holes, and Unconventional Cooling Paradigms

NASA Technical Reports Server (NTRS)

Shyam, Vikram; Thurman, Douglas R.; Poinsatte, Philip E.; Ameri, Ali A.; Culley, Dennis E.

2018-01-01

Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. Ways to quantify the efficacy of novel cooling holes that are asymmetric, not uniformly spaced or that show variation from hole to hole are presented. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and square holes. A patent-pending spiral hole design showed the highest potential of the nondiffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing ratios of 1.0, 1.5, 2.0, and 2.5 at a density ratio of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS. A section on ideas for future work is included that addresses issues of quantifying cooling uniformity and provides some ideas for changing the way we think about cooling such as changing the direction of cooling or coupling acoustic devices to cooling holes to regulate frequency.

Cooling Duct Analysis for Transpiration/Film Cooled Liquid Propellant Rocket Engines

NASA Technical Reports Server (NTRS)

Micklow, Gerald J.

1996-01-01

The development of a low cost space transportation system requires that the propulsion system be reusable, have long life, with good performance and use low cost propellants. Improved performance can be achieved by operating the engine at higher pressure and temperature levels than previous designs. Increasing the chamber pressure and temperature, however, will increase wall heating rates. This necessitates the need for active cooling methods such as film cooling or transpiration cooling. But active cooling can reduce the net thrust of the engine and add considerably to the design complexity. Recently, a metal drawing process has been patented where it is possible to fabricate plates with very small holes with high uniformity with a closely specified porosity. Such a metal plate could be used for an inexpensive transpiration/film cooled liner to meet the demands of advanced reusable rocket engines, if coolant mass flow rates could be controlled to satisfy wall cooling requirements and performance. The present study investigates the possibility of controlling the coolant mass flow rate through the porous material by simple non-active fluid dynamic means. The coolant will be supplied to the porous material by series of constant geometry slots machined on the exterior of the engine.

Plug-Load Control and Behavioral Change Research in GSA Office Buildings

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

Metzger, I.; Cutler, D.; Sheppy, M.

2012-10-01

The U.S. General Services Administration (GSA) owns and leases over 354 million square feet (ft2) of space in over 9,600 buildings [1]. GSA is a leader among federal agencies in aggressively pursuing energy efficiency (EE) opportunities for its facilities and installing renewable energy (RE) systems to provide heating, cooling, and power to these facilities. According to several energy assessments of GSA's buildings conducted by the National Renewable Energy Laboratory (NREL), plug-loads account for approximately 21% of the total electricity consumed within a standard GSA Region 3 office building. This study aims to provide insight on how to effectively manage plug-loadmore » energy consumption and attain higher energy and cost savings for plug-loads. As GSA improves the efficiency of its building stock, plug-loads will become an even greater portion of its energy footprint.« less

SSTL UK-DMC SLIM-6 data quality assessment

USGS Publications Warehouse

Chander, G.; Saunier, S.; Choate, M.J.; Scaramuzza, P.L.

2009-01-01

Satellite data from the Surrey Satellite Technology Limited (SSTL) United Kingdom (UK) Disaster Monitoring Constellation (DMC) were assessed for geometric and radiometric quality. The UK-DMC Surrey Linear Imager 6 (SLIM-6) sensor has a 32-m spatial resolution and a ground swath width of 640 km. The UK-DMC SLIM-6 design consists of a three-band imager with green, red, and near-infrared bands that are set to similar bandpass as Landsat bands 2, 3, and 4. The UK-DMC data consisted of imagery registered to Landsat orthorectified imagery produced from the GeoCover program. Relief displacements within the UK-DMC SLIM-6 imagery were accounted for by using global 1-km digital elevation models available through the Global Land One-km Base Elevation (GLOBE) Project. Positional accuracy and relative band-to-band accuracy were measured. Positional accuracy of the UK-DMC SLIM-6 imagery was assessed by measuring the imagery against digital orthophoto quadrangles (DOQs), which are designed to meet national map accuracy standards at 1 : 24 000 scales; this corresponds to a horizontal root-mean-square accuracy of about 6 m. The UK-DMC SLIM-6 images were typically registered to within 1.0-1.5 pixels to the DOQ mosaic images. Several radiometric artifacts like striping, coherent noise, and flat detector were discovered and studied. Indications are that the SSTL UK-DMC SLIM-6 data have few artifacts and calibration challenges, and these can be adjusted or corrected via calibration and processing algorithms. The cross-calibration of the UK-DMC SLIM-6 and Landsat 7 Enhanced Thematic Mapper Plus was performed using image statistics derived from large common areas observed by the two sensors.

Water cooled steam jet

DOEpatents

Wagner, Jr., Edward P.

1999-01-01

A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed therebetween. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock.

Water cooled steam jet

DOEpatents

Wagner, E.P. Jr.

1999-01-12

A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed there between. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock. 2 figs.

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.

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.

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

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

High-power closed-cycle 4He cryostat with top-loading sample exchange

NASA Astrophysics Data System (ADS)

Piegsa, F. M.; van den Brandt, B.; Kirch, K.

2017-10-01

We report on the development of a versatile cryogen-free laboratory cryostat based upon a commercial pulse tube cryocooler. It provides enough cooling power for continuous recondensation of circulating 4He gas at a condensation pressure of approximately 250 mbar. Moreover, the cryostat allows for exchange of different cryostat-inserts as well as fast and easy ;wet; top-loading of samples directly into the 1 K pot with a turn-over time of less than 75 min. Starting from room temperature and using a 4He cryostat-insert, a base temperature of 1.0 K is reached within approximately seven hours and a cooling power of 250 mW is established at 1.24 K.

Performance of Air-cooled Engine Cylinders Using Blower Cooling

NASA Technical Reports Server (NTRS)

Schey, Oscar W; Ellerbrock, Herman H , Jr

1936-01-01

An investigation was made to obtain information on the minimum quantity of air and power required to cool conventional air cooled cylinders at various operating conditions when using a blower. The results of these tests show that the minimum power required for satisfactory cooling with an overall blower efficiency of 100 percent varied from 2 to 6 percent of the engine power depending on the operating conditions. The shape of the jacket had a large effect on the cylinder temperatures. Increasing the air speed over the front of the cylinder by keeping the greater part of the circumference of the cylinder covered by the jacket reduced the temperatures over the entire cylinder.

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.

Evaporatively cooled chiller for solar air conditioning systems design and field test

NASA Astrophysics Data System (ADS)

Merrick, R. H.; Murray, J. G.

1984-06-01

Design changes to improve reliability, part load performance, and manufacturability characteristics of the chiller are focused upon. Low heat flux was achieved by large transfer area allows scale formation without being a thermal barrier: 80 mils = 1 deg. The scaling rate is minimized by keeping surface temperatures below 100 F and a generous water recirculation flow rate. By integrating the cooling tower function into the chiller itself parasitic power consumption was reduced 35%. This system also provided the winter freeze protection without the specific manual shut down procedures required by separate water cooled units and their towers. The severe reduction in cumulative coefficient of performance (COP) due to cycling conditions has been substantially reduced using the spin down control scheme. The major disappointment was the failure to develop a satisfactory inexpensive protective coating. Hot dip galvanizing was demonstrated to be effective but costly, partially due to transportation expense.

Low-cycle fatigue analysis of a cooled copper combustion chamber

NASA Technical Reports Server (NTRS)

Miller, R. W.

1974-01-01

A three-dimensional finite element elastoplastic strain analysis was performed for the throat section of regeneratively cooled rocket engine combustion chamber. The analysis included thermal and pressure loads, and the effects of temperature dependent material properties, to determine the strain range corresponding to the engine operating cycle. The strain range was used in conjunction with OFHC copper isothermal fatigue test data to predict engine low-cycle fatigue life. The analysis was performed for chamber configuration and operating conditions corresponding to a hydrogen-oxygen chamber which was fatigue tested to failure at the NASA Lewis Research Center.

Yahoo! Compute Coop (YCC). A Next-Generation Passive Cooling Design for Data Centers

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

Robison, AD; Page, Christina; Lytle, Bob

The purpose of the Yahoo! Compute Coop (YCC) project is to research, design, build and implement a greenfield "efficient data factory" and to specifically demonstrate that the YCC concept is feasible for large facilities housing tens of thousands of heat-producing computing servers. The project scope for the Yahoo! Compute Coop technology includes: - Analyzing and implementing ways in which to drastically decrease energy consumption and waste output. - Analyzing the laws of thermodynamics and implementing naturally occurring environmental effects in order to maximize the "free-cooling" for large data center facilities. "Free cooling" is the direct usage of outside air tomore » cool the servers vs. traditional "mechanical cooling" which is supplied by chillers or other Dx units. - Redesigning and simplifying building materials and methods. - Shortening and simplifying build-to-operate schedules while at the same time reducing initial build and operating costs. Selected for its favorable climate, the greenfield project site is located in Lockport, NY. Construction on the 9.0 MW critical load data center facility began in May 2009, with the fully operational facility deployed in September 2010. The relatively low initial build cost, compatibility with current server and network models, and the efficient use of power and water are all key features that make it a highly compatible and globally implementable design innovation for the data center industry. Yahoo! Compute Coop technology is designed to achieve 99.98% uptime availability. This integrated building design allows for free cooling 99% of the year via the building's unique shape and orientation, as well as server physical configuration.« less

DEVELOPMENT OF A SOFTWARE DESIGN TOOL FOR HYBRID SOLAR-GEOTHERMAL HEAT PUMP SYSTEMS IN HEATING- AND COOLING-DOMINATED BUILDINGS

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

Yavuzturk, C. C.; Chiasson, A. D.; Filburn, T. P.

This project provides an easy-to-use, menu-driven, software tool for designing hybrid solar-geothermal heat pump systems (GHP) for both heating- and cooling-dominated buildings. No such design tool currently exists. In heating-dominated buildings, the design approach takes advantage of glazed solar collectors to effectively balance the annual thermal loads on the ground with renewable solar energy. In cooling-dominated climates, the design approach takes advantage of relatively low-cost, unglazed solar collectors as the heat rejecting component. The primary benefit of hybrid GHPs is the reduced initial cost of the ground heat exchanger (GHX). Furthermore, solar thermal collectors can be used to balance themore » ground loads over the annual cycle, thus making the GHX fully sustainable; in heating-dominated buildings, the hybrid energy source (i.e., solar) is renewable, in contrast to a typical fossil fuel boiler or electric resistance as the hybrid component; in cooling-dominated buildings, use of unglazed solar collectors as a heat rejecter allows for passive heat rejection, in contrast to a cooling tower that consumes a significant amount of energy to operate, and hybrid GHPs can expand the market by allowing reduced GHX footprint in both heating- and cooling-dominated climates. The design tool allows for the straight-forward design of innovative GHP systems that currently pose a significant design challenge. The project lays the foundations for proper and reliable design of hybrid GHP systems, overcoming a series of difficult and cumbersome steps without the use of a system simulation approach, and without an automated optimization scheme. As new technologies and design concepts emerge, sophisticated design tools and methodologies must accompany them and be made usable for practitioners. Lack of reliable design tools results in reluctance of practitioners to implement more complex systems. A menu-driven software tool for the design of hybrid solar GHP systems

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

A small scale remote cooling system for a superconducting cyclotron magnet

NASA Astrophysics Data System (ADS)

Haug, F.; Berkowitz Zamorra, D.; Michels, M.; Gomez Bosch, R.; Schmid, J.; Striebel, A.; Krueger, A.; Diez, M.; Jakob, M.; Keh, M.; Herberger, W.; Oesterle, D.

2017-02-01

Through a technology transfer program CERN is involved in the R&D of a compact superconducting cyclotron for future clinical radioisotope production, a project led by the Spanish research institute CIEMAT. For the remote cooling of the LTc superconducting magnet operating at 4.5 K, CERN has designed a small scale refrigeration system, the Cryogenic Supply System (CSS). This refrigeration system consists of a commercial two-stage 1.5 W @ 4.2 K GM cryocooler and a separate forced flow circuit. The forced flow circuit extracts the cooling power of the first and the second stage cold tips, respectively. Both units are installed in a common vacuum vessel and, at the final configuration, a low loss transfer line will provide the link to the magnet cryostat for the cooling of the thermal shield with helium at 40 K and the two superconducting coils with two-phase helium at 4.5 K. Currently the CSS is in the testing phase at CERN in stand-alone mode without the magnet and the transfer line. We have added a “validation unit” housed in the vacuum vessel of the CSS representing the thermo-hydraulic part of the cyclotron magnet. It is equipped with electrical heaters which allow the simulation of the thermal loads of the magnet cryostat. A cooling power of 1.4 W at 4.5 K and 25 W at the thermal shield temperature level has been measured. The data produced confirm the design principle of the CSS which could be validated.

Cold perception and cutaneous microvascular response to local cooling at different cooling temperatures.

PubMed

Music, Mark; Finderle, Zarko; Cankar, Ksenija

2011-05-01

The aim of the present study was to investigate the effect of quantitatively measured cold perception (CP) thresholds on microcirculatory response to local cooling as measured by direct and indirect response of laser-Doppler (LD) flux during local cooling at different temperatures. The CP thresholds were measured in 18 healthy males using the Marstock method (thermode placed on the thenar). The direct (at the cooling site) and indirect (on contralateral hand) LD flux responses were recorded during immersion of the hand in a water bath at 20°C, 15°C, and 10°C. The cold perception threshold correlated (linear regression analysis, Pearson correlation) with the indirect LD flux response at cooling temperatures 20°C (r=0.782, p<0.01) and 15°C (r=0.605, p<0.01). In contrast, there was no correlation between the CP threshold and the indirect LD flux response during cooling in water at 10°C. The results demonstrate that during local cooling, depending on the cooling temperature used, cold perception threshold influences indirect LD flux response. Copyright © 2011 Elsevier Inc. All rights reserved.

Modelling reduction of urban heat load in Vienna by modifying surface properties of roofs

NASA Astrophysics Data System (ADS)

Žuvela-Aloise, Maja; Andre, Konrad; Schwaiger, Hannes; Bird, David Neil; Gallaun, Heinz

2018-02-01

The study examines the potential of urban roofs to reduce the urban heat island (UHI) effect by changing their reflectivity and implementing vegetation (green roofs) using the example of the City of Vienna. The urban modelling simulations are performed based on high-resolution orography and land use data, climatological observations, surface albedo values from satellite imagery and registry of the green roof potential in Vienna. The modelling results show that a moderate increase in reflectivity of roofs (up to 0.45) reduces the mean summer temperatures in the densely built-up environment by approximately 0.25 °C. Applying high reflectivity materials (roof albedo up to 0.7) leads to average cooling in densely built-up area of approximately 0.5 °C. The green roofs yield a heat load reduction in similar order of magnitude as the high reflectivity materials. However, only 45 % of roof area in Vienna is suitable for greening and the green roof potential mostly applies to industrial areas in city outskirts and is therefore not sufficient for substantial reduction of the UHI effect, particularly in the city centre which has the highest heat load. The strongest cooling effect can be achieved by combining the green roofs with high reflectivity materials. In this case, using 50 or 100 % of the green roof potential and applying high reflectivity materials on the remaining surfaces have a similar cooling effect.

Science education reforms in the UK.

PubMed

2012-10-01

As children return to school at the end of the summer in the UK, planned reforms aim to increase their science and maths literacy. A comprehensive foundation in these essential subjects is necessary to ensure that the UK remains at the forefront of science and technology for decades to come.

Flightweight radiantly and actively cooled panel: Thermal and structural performance

NASA Technical Reports Server (NTRS)

Shore, C. P.; Nowak, R. J.; Kelly, H. N.

1982-01-01

A 2- by 4-ft flightweight panel was subjected to thermal/structural tests representative of design flight conditions for a Mach 6.7 transport and to off-design conditions simulating flight maneuvers and cooling system failures. The panel utilized Rene 41 heat shields backed by a thin layer of insulation to radiate away most of the 12 Btu/ft2-sec incident heating. A solution of ethylene glycol in water circulating through tubes in an aluminum-honeycomb-sandwich panel absorbed the remainder of the incident heating (0.8 Btu/sq ft-sec). The panel successfully withstood (1) 46.7 hr of radiant heating which included 53 thermal cycles and 5000 cycles of uniaxial inplane loading of + or - 1200 lfb/in; (2) simulated 2g-maneuver heating conditions and simulated cooling system failures without excessive temperatures on the structural panel; and (3) the extensive thermal/structural tests and the aerothermal tests reported in NASA TP-1595 without significant damage to the structural panel, coolant leaks, or hot-gas ingress to the structural panel.

Kilowatt-level direct-'refractive index matching liquid'-cooled Nd:YLF thin disk laser resonator.

PubMed

Ye, Zhibin; Liu, Chong; Tu, Bo; Wang, Ke; Gao, Qingsong; Tang, Chun; Cai, Zhen

2016-01-25

A direct-liquid-cooled Nd:YLF thin disk laser resonator is presented, which features the use of refractive index matching liquid (RIML) as coolant. Highly uniform pump intensity distribution with rectangular shape is realized by using metallic planar waveguides. Much attention has been paid on the design of the gain module, including how to achieve excellent cooling ability with multi-channel coolers and how to choose the doping levels of the crystals for realizing well-distributed pump absorption. The flow velocity of the coolant is found to be a key parameter for laser performance and optimized to keep it in laminar flow status for dissipating unwanted heat load. A single channel device is used to measure the convective heat transfer coefficient (CHTC) at different flow velocities. Accordingly, the thermal stress in the disk is analyzed numerically and the maximum permissible thermal load is estimated. Experimentally, with ten pieces of a-cut Nd:YLF thin disks of different doping levels, a linear polarized laser with an average output power of 1120 W is achieved at the pump power of 5202 W, corresponding to an optical-optical efficiency of 21.5%, and a slope efficiency of 30.8%. Furthermore, the wavefront aberration of the gain module is measured to be quite weak, with a peak to valley (PV) value of 4.0 μm when it is pumped at 5202 W, which enables the feasibility of its application in an unstable resonator. To the best of our knowledge, this is the first demonstration of kilowatt-level direct-'refractive index matching liquid'-cooled Nd:YLF thin disk laser resonator.

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.

Liquid-Cooled Garment

NASA Technical Reports Server (NTRS)

1977-01-01

A liquid-cooled bra, offshoot of Apollo moon suit technology, aids the cancer-detection technique known as infrared thermography. Water flowing through tubes in the bra cools the skin surface to improve resolution of thermograph image.

Cooling Water Intakes

EPA Pesticide Factsheets

Industries use large volumes of water for cooling. The water intakes pull large numbers of fish and other organisms into the cooling systems. EPA issues regulations on intake structures in order to minimize adverse environmental impacts.

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.

Airfoil, platform, and cooling passage measurements on a rotating transonic high-pressure turbine

NASA Astrophysics Data System (ADS)

Nickol, Jeremy B.

compressibility effects within the cooling holes which are not present in low speed experiments. Another major focus of this work is on the forward purge cavity and rotor and stator inner endwalls. Pressure and heat transfer measurements are taken at several locations, and compared as both forward and aft purge flow rates are varied. It is seen that increases in forward purge rates result in a flow blockage and greater pressure on the endwalls both up and downstream of the cavity. Thus, even in locations where the coolant does not directly cover the metal surface, it can have a significant impact on the local pressure loading and heat transfer rate. The heat transfer on the platform further downstream, however, is unchanged by variations in purge flow rates.

Laminated turbine vane design and fabrication. [utilizing film cooling as a cooling system

NASA Technical Reports Server (NTRS)

Hess, W. G.

1979-01-01

A turbine vane and associated endwalls designed for advanced gas turbine engine conditions are described. The vane design combines the methods of convection cooling and selective areas of full coverage film cooling. The film cooling technique is utilized on the leading edge, pressure side, and endwall regions. The turbine vane involves the fabrication of airfoils from a stack of laminates with cooling passages photoetched on the surface. Cold flow calibration tests, a thermal analysis, and a stress analysis were performed on the turbine vanes.

Liquid cooled garments

NASA Technical Reports Server (NTRS)

1975-01-01

Liquid cooled garments employed in several applications in which severe heat is encountered are discussed. In particular, the use of the garments to replace air line cooling units in a variety of industrial processing situations is discussed.

Hydronic rooftop cooling systems

DOEpatents

Bourne, Richard C [Davis, CA; Lee, Brian Eric [Monterey, CA; Berman, Mark J [Davis, CA

2008-01-29

A roof top cooling unit has an evaporative cooling section that includes at least one evaporative module that pre-cools ventilation air and water; a condenser; a water reservoir and pump that captures and re-circulates water within the evaporative modules; a fan that exhausts air from the building and the evaporative modules and systems that refill and drain the water reservoir. The cooling unit also has a refrigerant section that includes a compressor, an expansion device, evaporator and condenser heat exchangers, and connecting refrigerant piping. Supply air components include a blower, an air filter, a cooling and/or heating coil to condition air for supply to the building, and optional dampers that, in designs that supply less than 100% outdoor air to the building, control the mixture of return and ventilation air.

Air-Cooled Turbine Blades with Tip Cap For Improved Leading-Edge Cooling

NASA Technical Reports Server (NTRS)

Calvert, Howard F.; Meyer, Andre J., Jr.; Morgan, William C.

1959-01-01

An investigation was conducted in a modified turbojet engine to determine the cooling characteristics of the semistrut corrugated air- cooled turbine blade and to compare and evaluate a leading-edge tip cap as a means for improving the leading-edge cooling characteristics of cooled turbine blades. Temperature data were obtained from uncapped air-cooled blades (blade A), cooled blades with the leading-edge tip area capped (blade B), and blades with slanted corrugations in addition to leading-edge tip caps (blade C). All data are for rated engine speed and turbine-inlet temperature (1660 F). A comparison of temperature data from blades A and B showed a leading-edge temperature reduction of about 130 F that could be attributed to the use of tip caps. Even better leading-edge cooling was obtained with blade C. Blade C also operated with the smallest chordwise temperature gradients of the blades tested, but tip-capped blade B operated with the lowest average chordwise temperature. According to a correlation of the experimental data, all three blade types 0 could operate satisfactorily with a turbine-inlet temperature of 2000 F and a coolant flow of 3 percent of engine mass flow or less, with an average chordwise temperature limit of 1400 F. Within the range of coolant flows investigated, however, only blade C could maintain a leading-edge temperature of 1400 F for a turbine-inlet temperature of 2000 F.

The future of learning disabilities nursing in the UK.

PubMed

Clapham, Anthony

2014-07-02

This article appraises the report Strengthening the Commitment, which is a UK-wide review of learning disabilities nursing by the UK's four chief nursing officers. Strengthening the Commitment has strategic importance in reviewing progress in the care of people with learning disabilities in the UK. It also has a role in helping to guide future strategies and initiatives addressing the continuing health inequalities experienced by people with learning disabilities throughout the UK.

Grade Inflation in UK Higher Education

ERIC Educational Resources Information Center

Bachan, Ray

2017-01-01

This paper examines the continual increase in the proportion of "good" honour degrees awarded by UK universities since the mid-2000s. This trend has brought with it the charge of "grade inflation" that may reflect falling standards in UK higher education. This issue has been raised in the national press and in government which…

Experimental investigation of temperature rise in bone drilling with cooling: A comparison between modes of without cooling, internal gas cooling, and external liquid cooling.

PubMed

Shakouri, Ehsan; Haghighi Hassanalideh, Hossein; Gholampour, Seifollah

2018-01-01

Bone fracture occurs due to accident, aging, and disease. For the treatment of bone fractures, it is essential that the bones are kept fixed in the right place. In complex fractures, internal fixation or external methods are used to fix the fracture position. In order to immobilize the fracture position and connect the holder equipment to it, bone drilling is required. During the drilling of the bone, the required forces to chip formation could cause an increase in the temperature. If the resulting temperature increases to 47 °C, it causes thermal necrosis of the bone. Thermal necrosis decreases bone strength in the hole and, subsequently, due to incomplete immobilization of bone, fracture repair is not performed correctly. In this study, attempts have been made to compare local temperature increases in different processes of bone drilling. This comparison has been done between drilling without cooling, drilling with gas cooling, and liquid cooling on bovine femur. Drilling tests with gas coolant using direct injection of CO 2 and N 2 gases were carried out by internal coolant drill bit. The results showed that with the use of gas coolant, the elevation of temperature has limited to 6 °C and the thermal necrosis is prevented. Maximum temperature rise reached in drilling without cooling was 56 °C, using gas and liquid coolant, a maximum temperature elevation of 43 °C and 42 °C have been obtained, respectively. This resulted in decreased possibility of thermal necrosis of bone in drilling with gas and liquid cooling. However, the results showed that the values obtained with the drilling method with direct gas cooling are independent of the rotational speed of drill.

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.

Evaluation of advanced cooling therapy's esophageal cooling device for core temperature control.

PubMed

Naiman, Melissa; Shanley, Patrick; Garrett, Frank; Kulstad, Erik

2016-05-01

Managing core temperature is critical to patient outcomes in a wide range of clinical scenarios. Previous devices designed to perform temperature management required a trade-off between invasiveness and temperature modulation efficiency. The Esophageal Cooling Device, made by Advanced Cooling Therapy (Chicago, IL), was developed to optimize warming and cooling efficiency through an easy and low risk procedure that leverages heat transfer through convection and conduction. Clinical data from cardiac arrest, fever, and critical burn patients indicate that the Esophageal Cooling Device performs very well both in terms of temperature modulation (cooling rates of approximately 1.3°C/hour, warming of up to 0.5°C/hour) and maintaining temperature stability (variation around goal temperature ± 0.3°C). Physicians have reported that device performance is comparable to the performance of intravascular temperature management techniques and superior to the performance of surface devices, while avoiding the downsides associated with both.

Water-Cooled Optical Thermometer

NASA Technical Reports Server (NTRS)

Menna, A. A.

1987-01-01

Water-cooled optical probe measures temperature of nearby radiating object. Intended primarily for use in silicon-growing furnace for measuring and controlling temperatures of silicon ribbon, meniscus, cartridge surfaces, heaters, or other parts. Cooling water and flushing gas cool fiber-optic probe and keep it clean. Fiber passes thermal radiation from observed surface to measuring instrument.

Hypersonic aerospace vehicle leading edge cooling using heat pipe, transpiration and film cooling techniques

NASA Astrophysics Data System (ADS)

Modlin, James Michael

An investigation was conducted to study the feasibility of cooling hypersonic vehicle leading edge structures exposed to severe aerodynamic surface heat fluxes using a combination of liquid metal heat pipes and surface mass transfer cooling techniques. A generalized, transient, finite difference based hypersonic leading edge cooling model was developed that incorporated these effects and was demonstrated on an assumed aerospace plane-type wing leading edge section and a SCRAMJET engine inlet leading edge section. The hypersonic leading edge cooling model was developed using an existing, experimentally verified heat pipe model. Two applications of the hypersonic leading edge cooling model were examined. An assumed aerospace plane-type wing leading edge section exposed to a severe laminar, hypersonic aerodynamic surface heat flux was studied. A second application of the hypersonic leading edge cooling model was conducted on an assumed one-quarter inch nose diameter SCRAMJET engine inlet leading edge section exposed to both a transient laminar, hypersonic aerodynamic surface heat flux and a type 4 shock interference surface heat flux. The investigation led to the conclusion that cooling leading edge structures exposed to severe hypersonic flight environments using a combination of liquid metal heat pipe, surface transpiration, and film cooling methods appeared feasible.

Design and Implementation of a Thermal Load Reduction System for a Hyundai Sonata PHEV for Improved Range

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

Rugh, John P; Kreutzer, Cory J; Scott, Matthew

Increased adoption of electric-drive vehicles requires overcoming hurdles including limited vehicle range. Vehicle cabin heating and cooling demand for occupant climate control requires energy from the main battery and has been shown to significantly degrade vehicle range. During peak cooling and heating conditions, climate control can require as much as or more energy than propulsion. As part of an ongoing project, the National Renewable Energy Laboratory and project partners Hyundai America Technical Center, Inc., Gentherm, Pittsburgh Glass Works, PPG Industries, Sekisui, 3 M, and Hanon Systems developed a thermal load reduction system to reduce the range penalty associated with electricmore » vehicle climate control. Solar reflective paint, solar control glass, heated and cooled/ventilated seats, heated surfaces, and a heated windshield with door demisters were integrated into a Hyundai Sonata plug-in hybrid electric vehicle. Cold weather field-testing was conducted in Fairbanks, Alaska, and warm weather testing was conducted in Death Valley, California, to assess the system performance in comparison to the baseline production vehicle. In addition, environmental chamber testing at peak heating and cooling conditions was performed to assess the performance of the system in standardized conditions compared to the baseline. Experimental results are presented in this paper, providing quantitative data to automobile manufacturers on the impact of climate control thermal load reduction technologies to increase the advanced thermal technology adoption and market penetration of electric drive vehicles.« less

A Si/Glass Bulk-Micromachined Cryogenic Heat Exchanger for High Heat Loads: Fabrication, Test, and Application Results

PubMed Central

Zhu, Weibin; White, Michael J.; Nellis, Gregory F.; Klein, Sanford A.; Gianchandani, Yogesh B.

2010-01-01

This paper reports on a micromachined Si/glass stack recuperative heat exchanger with in situ temperature sensors. Numerous high-conductivity silicon plates with integrated platinum resistance temperature detectors (Pt RTDs) are stacked, alternating with low-conductivity Pyrex spacers. The device has a 1 × 1-cm2 footprint and a length of up to 3.5 cm. It is intended for use in Joule–Thomson (J–T) coolers and can sustain pressure exceeding 1 MPa. Tests at cold-end inlet temperatures of 237 K–252 K show that the heat exchanger effectiveness is 0.9 with 0.039-g/s helium mass flow rate. The integrated Pt RTDs present a linear response of 0.26%–0.30%/K over an operational range of 205 K–296 K but remain usable at lower temperatures. In self-cooling tests with ethane as the working fluid, a J–T system with the heat exchanger drops 76.1 K below the inlet temperature, achieving 218.7 K for a pressure of 835.8 kPa. The system reaches 200 K in transient state; further cooling is limited by impurities that freeze within the flow stream. In J–T self-cooling tests with an external heat load, the system reaches 239 K while providing 1 W of cooling. In all cases, there is an additional parasitic heat load estimated at 300–500 mW. PMID:20490284

NREL, LiquidCool Solutions Partner on Energy-Efficient Cooling for

Science.gov Websites

denser and generate more heat. Liquid cooling, including the LiquidCool Solutions technology, offers a more energy-efficient solution that also allows for effective reuse of the heat rejected by the water, depending on the coolant temperature and heat exchanger specifications. These water temperatures

Growing up with perinatal HIV: changes in clinical outcomes before and after transfer to adult care in the UK

PubMed Central

Judd, Ali; Collins, Intira Jeannie; Parrott, Francesca; Hill, Teresa; Jose, Sophie; Ford, Deborah; Asad, Hibo; Gibb, Diana M.; Sabin, Caroline

2017-01-01

Abstract Introduction: With improved survival, adolescents with perinatal HIV (PHIV) are transitioning from paediatric to adult care, but there are few published data on clinical outcomes post-transfer. Using linked data from patients in the national UK/Ireland paediatric cohort (CHIPS) and an adult UK cohort of outpatient clinics (UK CHIC), we describe mortality and changes in immunological status post-transfer. Methods: Participants in CHIPS aged ≥13 years by the end of 2013 were linked to the UK CHIC database. Mixed effects models explored changes in CD4 count before and after transfer, including interactions between time and variables where interaction p < 0.05. Results: Of 1,215 paediatric participants aged ≥13 years, 271 (22%) had linked data in UK CHIC. One hundred and forty-six (53%) were female, median age at last visit in paediatric care was 17 [interquartile range, IQR 16,18] years, median duration in paediatric care was 11.8 [6.6,15.5] years, and in adult care was 2.9 [1.5,5.9] years. At last visit in paediatric care, 74% (n = 200) were on ART, increasing to 84% (n = 228, p = 0.001) at last visit in adult care. In the 12 months before leaving paediatric care, 92 (47%) had two consecutive viral loads >400 copies/mL or one viral load >10,000 copies/mL, and likewise 102 (52%) in the 12 months post-transfer (p = 0.79). Seven (3%) people died in adult care. In multivariable analysis, CD4 declined as patients approached transition with a greater decline in those with higher nadir CD4 count (mean rates of decline of 3, 13, 15, 30 cells/mm3 per year for those with nadir CD4 < 100, 100–199, 200–299 and ≥300 cells/mm3, respectively). Post-transition, CD4 continued to decline in some groups (e.g. black males, −20 (−34, −5) cells/mm3 per year post transition, p = 0.007)) while it improved in others. Overall CD4 was higher with later year of birth (14 (7, 21) cells/mm3 per later year). There was no effect of age at transfer or

Data-Driven Residential Load Modeling and Validation in GridLAB-D

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

Gotseff, Peter; Lundstrom, Blake

Accurately characterizing the impacts of high penetrations of distributed energy resources (DER) on the electric distribution system has driven modeling methods from traditional static snap shots, often representing a critical point in time (e.g., summer peak load), to quasi-static time series (QSTS) simulations capturing all the effects of variable DER, associated controls and hence, impacts on the distribution system over a given time period. Unfortunately, the high time resolution DER source and load data required for model inputs is often scarce or non-existent. This paper presents work performed within the GridLAB-D model environment to synthesize, calibrate, and validate 1-second residentialmore » load models based on measured transformer loads and physics-based models suitable for QSTS electric distribution system modeling. The modeling and validation approach taken was to create a typical GridLAB-D model home that, when replicated to represent multiple diverse houses on a single transformer, creates a statistically similar load to a measured load for a given weather input. The model homes are constructed to represent the range of actual homes on an instrumented transformer: square footage, thermal integrity, heating and cooling system definition as well as realistic occupancy schedules. House model calibration and validation was performed using the distribution transformer load data and corresponding weather. The modeled loads were found to be similar to the measured loads for four evaluation metrics: 1) daily average energy, 2) daily average and standard deviation of power, 3) power spectral density, and 4) load shape.« less

MEIC electron cooling program

DOE PAGES

Derbenev, Yaroslav S.; Zhang, Yuhong

2014-12-01

Cooling of proton and ion beams is essential for achieving high luminosities (up to above 10 34 cm -2s -1) for MEIC, a Medium energy Electron-Ion Collider envisioned at JLab [1] for advanced nuclear science research. In the present conceptual design, we utilize the conventional election cooling method and adopted a multi-staged cooling scheme for reduction of and maintaining low beam emittances [2,3,4]. Two electron cooling facilities are required to support the scheme: one is a low energy (up to 2 MeV) DC cooler installed in the MEIC ion pre-booster (with the proton kinetic energy up to 3 GeV); themore » other is a high electron energy (up to 55 MeV) cooler in the collider ring (with the proton kinetic energy from 25 to 100 GeV). The high energy cooler, which is based on the ERL technology and a circulator ring, utilizes a bunched electron beam to cool bunched proton or ion beams. To complete the MEIC cooling concept and a technical design of the ERL cooler as well as to develop supporting technologies, an R&D program has been initiated at Jefferson Lab and significant progresses have been made since then. In this study, we present a brief description of the cooler design and a summary of the progress in this cooling R&D.« less

The risk of hydraulic fracturing on public health in the UK and the UK's fracking legislation.

PubMed

Reap, Elisabeth

2015-01-01

Hydraulic fracturing to extract natural gas from shale rock is a new, rapidly expanding industry in the United States (US). However, there is concern that these operations could be having large negative impacts such as groundwater contamination, increased air pollution and seismic events. The United Kingdom (UK) is looking at the potential for emulating the success of 'shale gas' in the US. Differences in population density and geological conditions mean that the public health impacts recorded in the US cannot be directly extrapolated to the UK. There is limited academic literature available but findings suggest that the UK government is not fully recognising the inherent risks of hydraulic fracturing exposed by this literature. Government reports suggest a reliance on engineering solutions and better practice to overcome problems found in the US when evidence suggests that there are inherent risks and impacts that cannot be eliminated. This study applies US results to approximate the impact of one exposure pathway, inhalation of hydrocarbons by the public from operational air emissions over the 30 year lifetime of a well and finds that 7.2 extra cancer cases from exposure to air contamination would be expected in the UK if all test sites, approved test sites and test sites awaiting approval as of January 2015 went on to extract gas. In conclusion, limited assessment of the public health implications of hydraulic fracturing operations is available but the UK government appears to not be applying the precautionary principle to potentially significant legislation.

Heat Load Sharing in a Capillary Pumped Loop with Multiple Evaporators and Multiple Condensers

NASA Technical Reports Server (NTRS)

Ku, Jentung

2005-01-01

This paper describes the heat load sharing function among multiple parallel evaporators in a capillary pumped loop (CPL). In the normal mode of operation, the evaporators cool the instruments by absorbing the waste heat. When an instruments is turned off, the attached evaporator can keep it warm by receiving heat from other evaporators serving the operating instruments. This is referred to as heat load sharing. A theoretical basis of heat load sharing is given first. The fact that the wicks in the powered evaporators will develop capillary pressure to force the generated vapor to flow to cold locations where the pressure is lower leads to the conclusion that heat load sharing is an inherent function of a CPL with multiple evaporators. Heat load sharing has been verified with many CPLs in ground tests. Experimental results of the Capillary Pumped Loop 3 (CAPL 3) Flight Experiment are presented in this paper. Factors that affect the amount of heat being shared are discussed. Some constraints of heat load sharing are also addressed.

Effectiveness-weighted control of cooling system components

DOEpatents

Campbell, Levi A.; Chu, Richard C.; David, Milnes P.; Ellsworth Jr., Michael J.; Iyengar, Madhusudan K.; Schmidt, Roger R.; Simmons, Robert E.

2015-12-22

Energy efficient control of cooling system cooling of an electronic system is provided based, in part, on weighted cooling effectiveness of the components. The control includes automatically determining speed control settings for multiple adjustable cooling components of the cooling system. The automatically determining is based, at least in part, on weighted cooling effectiveness of the components of the cooling system, and the determining operates to limit power consumption of at least the cooling system, while ensuring that a target temperature associated with at least one of the cooling system or the electronic system is within a desired range by provisioning, based on the weighted cooling effectiveness, a desired target temperature change among the multiple adjustable cooling components of the cooling system. The provisioning includes provisioning applied power to the multiple adjustable cooling components via, at least in part, the determined control settings.

Nighttime Infrared radiative cooling and opacity inferred by REMS Ground Temperature Sensor Measurements

NASA Astrophysics Data System (ADS)

Martín-Torres, Javier; Paz Zorzano, María; Pla-García, Jorge; Rafkin, Scot; Lepinette, Alain; Sebastián, Eduardo; Gómez-Elvira, Javier; REMS Team

2013-04-01

Due to the low density of the Martian atmosphere, the temperature of the surface is controlled primarily by solar heating, and infrared cooling to the atmosphere and space, rather than heat exchange with the atmosphere. In the absence of solar radiation the infrared (IR) cooling, and then the nighttime surface temperatures, are directly controlled by soil termal inertia and atmospheric optical thickness (τ) at infrared wavelengths. Under non-wind conditions, and assuming no processes involving latent heat changes in the surface, for a particular site where the rover stands the main parameter controlling the IR cooling will be τ. The minimal ground temperature values at a fixed position may thus be used to detect local variations in the total dust/aerosols/cloud tickness. The Ground Temperature Sensor (GTS) and Air Temperature Sensor (ATS) in the Rover Environmental Monitoring Station (REMS) on board the Mars Science Laboratory (MSL) Curiosity rover provides hourly ground and air temperature measurements respectively. During the first 100 sols of operation of the rover, within the area of low thermal inertia, the minimal nightime ground temperatures reached values between 180 K and 190 K. For this season the expected frost point temperature is 200 K. Variations of up to 10 K have been observed associated with dust loading at Gale at the onset of the dust season. We will use these measurements together with line-by-line radiative transfer simulations using the Full Transfer By Optimized LINe-by-line (FUTBOLIN) code [Martín-Torres and Mlynczak, 2005] to estimate the IR atmospheric opacity and then dust/cloud coverage over the rover during the course of the MSL mission. Monitoring the dust loading and IR nightime cooling evolution during the dust season will allow for a better understanding of the influence of the atmosphere on the ground temperature and provide ground truth to models and orbiter measurements. References Martín-Torres, F. J. and M. G. Mlynczak

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.

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...

Auto-DR and Pre-cooling of Buildings at Tri-City Corporate Center

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

Yin, Rongxin; Xu, Peng; Kiliccote, Sila

2008-11-01

Over the several past years, Lawrence Berkeley National Laboratory (LBNL) has conducted field tests for different pre-cooling strategies in different commercial buildings within California. The test results indicated that pre-cooling strategies were effective in reducing electric demand in these buildings during peak periods. This project studied how to optimize pre-cooling strategies for eleven buildings in the Tri-City Corporate Center, San Bernardino, California with the assistance of a building energy simulation tool -- the Demand Response Quick Assessment Tool (DRQAT) developed by LBNL's Demand Response Research Center funded by the California Energy Commission's Public Interest Energy Research (PIER) Program. From themore » simulation results of these eleven buildings, optimal pre-cooling and temperature reset strategies were developed. The study shows that after refining and calibrating initial models with measured data, the accuracy of the models can be greatly improved and the models can be used to predict load reductions for automated demand response (Auto-DR) events. This study summarizes the optimization experience of the procedure to develop and calibrate building models in DRQAT. In order to confirm the actual effect of demand response strategies, the simulation results were compared to the field test data. The results indicated that the optimal demand response strategies worked well for all buildings in the Tri-City Corporate Center. This study also compares DRQAT with other building energy simulation tools (eQUEST and BEST). The comparison indicate that eQUEST and BEST underestimate the actual demand shed of the pre-cooling strategies due to a flaw in DOE2's simulation engine for treating wall thermal mass. DRQAT is a more accurate tool in predicting thermal mass effects of DR events.« less

Experimental study on the cool storage performance of super absorbent polymers for cool storage clothes

NASA Astrophysics Data System (ADS)

Li, Shidong; Mo, Caisong; Wang, Junze; Zheng, Jingfu; Tian, Ruhong

2017-11-01

In this paper, a kind of cool storage clothes which can cool the human body in high temperature condition is put forward. super absorbent polymers was selected as a cold storage material, through at the normal and extreme environment simulation, the cold storage materials were prepared with different composition, and their performance was tested. Test results show that:under normal temperature conditions, the 1:50 concentration of super absorbent polymers continued to release the longest cooling time, compared with pure water, cooling time extended 43 minutes by about 30%; under the condition of 37°C, the 1:100 concentration of super absorbent polymers continued to release the longest cooling time, compared with pure water, cooling time extended 105 minutes by about 50%.

Laser cooling by adiabatic transfer

NASA Astrophysics Data System (ADS)

Norcia, Matthew; Cline, Julia; Bartolotta, John; Holland, Murray; Thompson, James

2017-04-01

We have demonstrated a new method of laser cooling applicable to particles with narrow linewidth optical transitions. This simple and robust cooling mechanism uses a frequency-swept laser to adiabatically transfer atoms between internal and motional states. The role of spontaneous emission is reduced (though is still critical) compared to Doppler cooling. This allows us to achieve greater slowing forces than would be possible with Doppler cooling, and may make this an appealing technique for cooling molecules. In this talk, I will present a demonstration of this technique in a cold strontium system. DARPA QUASAR, NIST, NSF PFC.

Activated Carbon-hydrogen based Continuous Sorption Cooling in Single Adsorbent Bed with LN2 Heat Sink

NASA Astrophysics Data System (ADS)

Koley, Susmita; Ghosh, Indranil

Quick and periodic inflow-outflow of adsorbate in an adsorbent column createsa differential temperature between the two ends of it, allowing for the generation of continuous sorption cooling in a single adsorbent tube. The concept has been proven experimentally and theoretically for near room temperature applications using activated carbon-nitrogen. The feasibility of generating continuous solid sorption cooling in a single adsorbent tube in the cryogenic domainhas been studied theoretically with a different adsorbent-adsorbate pair, namely, activated carbon-hydrogen. Precooling of gaseous hydrogen (before it enters the adsorbent column) and removal of the heat of adsorption has been achieved using liquid nitrogen. Theoretical estimation shows nearly 20 K temperature difference between the two ends under no load condition. Finally, parametric variations have been performed.

Power electronics cooling apparatus

DOEpatents

Sanger, Philip Albert; Lindberg, Frank A.; Garcen, Walter

2000-01-01

A semiconductor cooling arrangement wherein a semiconductor is affixed to a thermally and electrically conducting carrier such as by brazing. The coefficient of thermal expansion of the semiconductor and carrier are closely matched to one another so that during operation they will not be overstressed mechanically due to thermal cycling. Electrical connection is made to the semiconductor and carrier, and a porous metal heat exchanger is thermally connected to the carrier. The heat exchanger is positioned within an electrically insulating cooling assembly having cooling oil flowing therethrough. The arrangement is particularly well adapted for the cooling of high power switching elements in a power bridge.

Passive containment cooling system

DOEpatents

Conway, Lawrence E.; Stewart, William A.

1991-01-01

A containment cooling system utilizes a naturally induced air flow and a gravity flow of water over the containment shell which encloses a reactor core to cool reactor core decay heat in two stages. When core decay heat is greatest, the water and air flow combine to provide adequate evaporative cooling as heat from within the containment is transferred to the water flowing over the same. The water is heated by heat transfer and then evaporated and removed by the air flow. After an initial period of about three to four days when core decay heat is greatest, air flow alone is sufficient to cool the containment.

Lattice design and expected performance of the Muon Ionization Cooling Experiment demonstration of ionization cooling

NASA Astrophysics Data System (ADS)

Bogomilov, M.; Tsenov, R.; Vankova-Kirilova, G.; Song, Y.; Tang, J.; Li, Z.; Bertoni, R.; Bonesini, M.; Chignoli, F.; Mazza, R.; Palladino, V.; de Bari, A.; Cecchet, G.; Orestano, D.; Tortora, L.; Kuno, Y.; Ishimoto, S.; Filthaut, F.; Jokovic, D.; Maletic, D.; Savic, M.; Hansen, O. M.; Ramberger, S.; Vretenar, M.; Asfandiyarov, R.; Blondel, A.; Drielsma, F.; Karadzhov, Y.; Charnley, G.; Collomb, N.; Dumbell, K.; Gallagher, A.; Grant, A.; Griffiths, S.; Hartnett, T.; Martlew, B.; Moss, A.; Muir, A.; Mullacrane, I.; Oates, A.; Owens, P.; Stokes, G.; Warburton, P.; White, C.; Adams, D.; Anderson, R. J.; Barclay, P.; Bayliss, V.; Boehm, J.; Bradshaw, T. W.; Courthold, M.; Francis, V.; Fry, L.; Hayler, T.; Hills, M.; Lintern, A.; Macwaters, C.; Nichols, A.; Preece, R.; Ricciardi, S.; Rogers, C.; Stanley, T.; Tarrant, J.; Tucker, M.; Wilson, A.; Watson, S.; Bayes, R.; Nugent, J. C.; Soler, F. J. P.; Gamet, R.; Barber, G.; Blackmore, V. J.; Colling, D.; Dobbs, A.; Dornan, P.; Hunt, C.; Kurup, A.; Lagrange, J.-B.; Long, K.; Martyniak, J.; Middleton, S.; Pasternak, J.; Uchida, M. A.; Cobb, J. H.; Lau, W.; Booth, C. N.; Hodgson, P.; Langlands, J.; Overton, E.; Robinson, M.; Smith, P. J.; Wilbur, S.; Dick, A. J.; Ronald, K.; Whyte, C. G.; Young, A. R.; Boyd, S.; Franchini, P.; Greis, J. R.; Pidcott, C.; Taylor, I.; Gardener, R. B. S.; Kyberd, P.; Nebrensky, J. J.; Palmer, M.; Witte, H.; Bross, A. D.; Bowring, D.; Liu, A.; Neuffer, D.; Popovic, M.; Rubinov, P.; DeMello, A.; Gourlay, S.; Li, D.; Prestemon, S.; Virostek, S.; Freemire, B.; Hanlet, P.; Kaplan, D. M.; Mohayai, T. A.; Rajaram, D.; Snopok, P.; Suezaki, V.; Torun, Y.; Onel, Y.; Cremaldi, L. M.; Sanders, D. A.; Summers, D. J.; Hanson, G. G.; Heidt, C.; MICE Collaboration

2017-06-01

Muon beams of low emittance provide the basis for the intense, well-characterized neutrino beams necessary to elucidate the physics of flavor at a neutrino factory and to provide lepton-antilepton collisions at energies of up to several TeV at a muon collider. The international Muon Ionization Cooling Experiment (MICE) aims to demonstrate ionization cooling, the technique by which it is proposed to reduce the phase-space volume occupied by the muon beam at such facilities. In an ionization-cooling channel, the muon beam passes through a material in which it loses energy. The energy lost is then replaced using rf cavities. The combined effect of energy loss and reacceleration is to reduce the transverse emittance of the beam (transverse cooling). A major revision of the scope of the project was carried out over the summer of 2014. The revised experiment can deliver a demonstration of ionization cooling. The design of the cooling demonstration experiment will be described together with its predicted cooling performance.

Tank Applied Testing of Load-Bearing Multilayer Insulation (LB-MLI)

NASA Technical Reports Server (NTRS)

Johnson, Wesley L.; Valenzuela, Juan G.; Feller, Jerr; Plachta, Dave

2014-01-01

The development of long duration orbital cryogenic storage systems will require the reduction of heat loads into the storage tank. In the case of liquid hydrogen, complete elimination of the heat load at 20 K is currently impractical due to the limitations in lift available on flight cryocoolers. In order to reduce the heat load, without having to remove heat at 20 K, the concept of Reduced Boil-Off uses cooled shields within the insulation system at approximately 90 K. The development of Load-Bearing Multilayer Insulation (LB-MLI) allowed the 90 K shield with tubing and cryocooler attachments to be suspended within the MLI and still be structurally stable. Coupon testing both thermally and structurally were performed to verify that the LB-MLI should work at the tank applied level. Then tank applied thermal and structural (acoustic) testing was performed to demonstrate the functionality of the LB-MLI as a structural insulation system. The LB-MLI showed no degradation of thermal performance due to the acoustic testing and showed excellent thermal performance when integrated with a 90 K class cryocooler on a liquid hydrogen tank.

Tank Applied Testing of Load-Bearing Multilayer Insulation (LB-MLI)

NASA Technical Reports Server (NTRS)

Johnson, Wesley L.; Valenzuela, Juan G.; Feller, Jeffrey R.; Plachta, David W.

2014-01-01