Solar Energy: Home Heating.

ERIC Educational Resources Information Center

Knapp, Henry H., III

This module on home heating is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies. The module…

Lunar Surface Stirling Power Systems Using Isotope Heat Sources

NASA Technical Reports Server (NTRS)

Schmitz, Paul C.; Penswick, L. Barry; Shaltens, Richard K.

2010-01-01

For many years, NASA has used the decay of plutonium-238 (Pu-238) (in the form of the General Purpose Heat Source (GPHS)) as a heat source for Radioisotope Thermoelectric Generators (RTGs), which have provided electrical power for many NASA missions. While RTGs have an impressive reliability record for the missions in which they have been used, their relatively low thermal to electric conversion efficiency and the scarcity of plutonium-238 (Pu-238) has led NASA to consider other power conversion technologies. NASA is considering returning both robotic and human missions to the lunar surface and, because of the long lunar nights (14.75 Earth days), isotope power systems are an attractive candidate to generate electrical power. NASA is currently developing the Advanced Stirling Radioisotope Generator (ASRG) as a candidate higher efficiency power system that produces greater than 160 W with two GPHS modules at the beginning of life (BOL) (32% efficiency). The ASRG uses the same Pu-238 GPHS modules, which are used in RTG, but by coupling them to a Stirling convertor provides a four-fold reduction in the number of GPHS modules. This study considers the use of americium-241 (Am-241) as a substitute for the Pu-238 in Stirling- convertor-based Radioisotope Power Systems (RPS) for power levels from tens of watts to 5 kWe. The Am-241 is used as a substitute for the Pu-238 in GPHS modules. Depending on power level, different Stirling heat input and removal systems are modeled. It was found that substituting Am-241 GPHS modules into the ASRG reduces power output by about one-fifth while maintaining approximately the same system mass. In order to obtain the nominal 160 W of electrical output of the Pu-238 ASRG requires 10 Am-241 GPHS modules. Higher power systems require changing from conductive coupling heat input and removal from the Stirling convertor to either pumped loops or heat pipes. Liquid metal pumped loops are considered as the primary heat transportation on the hot end and water pumped loop/heat pipe radiator is considered for the heat rejection side for power levels above 1 kWe.

Atmosphere-entry behavior of a modular, disk-shaped, isotope heat source.

NASA Technical Reports Server (NTRS)

Vorreiter, J. W.; Pitts, W. C.; Stine, H. A.; Burns, J. J.

1973-01-01

The authors have studied the entry and impact behavior of an isotope heat source for space nuclear power that disassembles into a number of modules which would enter the earth's atmosphere separately if a flight aborted. These modules are disk-shaped units, each with its own reentry heat shield and protective impact container. In normal operation, the disk modules are stacked inside the generator, but during a reentry abort they separate and fly as individual units of low ballistic coefficient. Flight tests at hypersonic speeds have confirmed that a stack of disks will separate and assume a flat-forward mode of flight. Free-fall tests of single disks have demonstrated a nominal impact velocity of 30 m/sec at sea level for a practical range of ballistic coefficients.

Thermoelectric generator having a resiliently mounted removable thermoelectric module

DOEpatents

Purdy, David L.; Shapiro, Zalman M.; Hursen, Thomas F.; Maurer, Gerould W.

1976-11-02

An electrical generator having an Isotopic Heat Capsule including radioactive fuel rod 21 as a primary heat source and Thermoelectric Modules 41 and 43 as converters. The Biological Shield for the Capsule is suspended from Spiders at each end each consisting of pretensioned rods 237 and 239 defining planes at right angles to each other. The Modules are mounted in cups 171 of transition members 173 of a heat rejection Fin Assembly whose fins 195 and 197 extend from both sides of the transition member 173 for effective cooling.

Investigation of Ionospheric Turbulence and Whistler Wave Interactions with Space Plasmas

DTIC Science & Technology

2012-11-21

an oscillating LOS velocity with the same periodicity as the heating modulation pattern. A set of Fourier periodogram from the MUIR LOS velocity...scale ionospheric turbulence are discussed separately, viz., (a) anomalous heat source-induced acoustic gravity waves (AGW), and (b) HF radio wave...ionospheric ducts, acoustic gravity waves (AGWs), anomalous heat sources, inner and outer radiation belts, L parameter, whistler wave interactions

Integrated application of combined cooling, heating and power poly-generation PV radiant panel system of zero energy buildings

NASA Astrophysics Data System (ADS)

Yin, Baoquan

2018-02-01

A new type of combined cooling, heating and power of photovoltaic radiant panel (PV/R) module was proposed, and applied in the zero energy buildings in this paper. The energy system of this building is composed of PV/R module, low temperature difference terminal, energy storage, multi-source heat pump, energy balance control system. Radiant panel is attached on the backside of the PV module for cooling the PV, which is called PV/R module. During the daytime, the PV module was cooled down with the radiant panel, as the temperature coefficient influence, the power efficiency was increased by 8% to 14%, the radiant panel solar heat collecting efficiency was about 45%. Through the nocturnal radiant cooling, the PV/R cooling capacity could be 50 W/m2. For the multifunction energy device, the system shows the versatility during the heating, cooling and power used of building utilization all year round.

General-Purpose Heat Source Safety Verification Test Program: Edge-on flyer plate tests

NASA Astrophysics Data System (ADS)

George, T. G.

1987-03-01

The radioisotope thermoelectric generator (RTG) that will supply power for the Galileo and Ulysses space missions contains 18 General-Purpose Heat Source (GPHS) modules. The GPHS modules provide power by transmitting the heat of Pu-238 alpha-decay to an array of thermoelectric elements. Each module contains four Pu-238O2-fueled clads and generates 250 W(t). Because the possibility of a launch vehicle explosion always exists, and because such an explosion could generate a field of high-energy fragments, the fueled clads within each GPHS module must survive fragment impact. The edge-on flyer plate tests were included in the Safety Verification Test series to provide information on the module/clad response to the impact of high-energy plate fragments. The test results indicate that the edge-on impact of a 3.2-mm-thick, aluminum-alloy (2219-T87) plate traveling at 915 m/s causes the complete release of fuel from capsules contained within a bare GPHS module, and that the threshold velocity sufficient to cause the breach of a bare, simulant-fueled clad impacted by a 3.5-mm-thick, aluminum-alloy (5052-TO) plate is approximately 140 m/s.

Technical Feasibility Evaluation on The Use of A Peltier Thermoelectric Module to Recover Automobile Exhaust Heat

NASA Astrophysics Data System (ADS)

Sugiartha, N.; Sastra Negara, P.

2018-01-01

A thermoelectric module composes of integrated p-n semiconductors as hot and cold side junctions and uses Seebeck effect between them to function as a thermoelectric generator (TEG) to directly convert heat into electrical power. Exhaust heat from engines as otherwise wasted to the atmosphere is one of the heat sources freely available to drive the TEG. This paper evaluates technical feasibility on the use of a Peltier thermoelectric module for energy recovery application of such kind of waste heat. An experimental apparatus has been setup to simulate real conditions of automobile engine exhaust piping system. It includes a square section aluminium ducting, an aluminium fin heat sink and a TEC1 12706 thermoelectric module. A heater and a cooling fan are employed to simulate hot exhaust gas and ambient air flows, respectively. Electrical loading is controlled by resistors. Dependent variables measured during the test are cold and hot side temperatures, open and loaded circuit output voltages and electrical current. The test results revealed a promising application of the Peltier thermoelectric module for the engine exhaust heat recovery, though the loaded output power produced and loaded output voltage are still far lower than the commercially thermoelectric module originally purposed for the TEG application.

Characterization of a high performance ultra-thin heat pipe cooling module for mobile hand held electronic devices

NASA Astrophysics Data System (ADS)

Ahamed, Mohammad Shahed; Saito, Yuji; Mashiko, Koichi; Mochizuki, Masataka

2017-11-01

In recent years, heat pipes have been widely used in various hand held mobile electronic devices such as smart phones, tablet PCs, digital cameras. With the development of technology these devices have different user friendly features and applications; which require very high clock speeds of the processor. In general, a high clock speed generates a lot of heat, which needs to be spreaded or removed to eliminate the hot spot on the processor surface. However, it is a challenging task to achieve proper cooling of such electronic devices mentioned above because of their confined spaces and concentrated heat sources. Regarding this challenge, we introduced an ultra-thin heat pipe; this heat pipe consists of a special fiber wick structure named as "Center Fiber Wick" which can provide sufficient vapor space on the both sides of the wick structure. We also developed a cooling module that uses this kind of ultra-thin heat pipe to eliminate the hot spot issue. This cooling module consists of an ultra-thin heat pipe and a metal plate. By changing the width, the flattened thickness and the effective length of the ultra-thin heat pipe, several experiments have been conducted to characterize the thermal properties of the developed cooling module. In addition, other experiments were also conducted to determine the effects of changes in the number of heat pipes in a single module. Characterization and comparison of the module have also been conducted both experimentally and theoretically.

Virtual welding equipment for simulation of GMAW processes with integration of power source regulation

NASA Astrophysics Data System (ADS)

Reisgen, Uwe; Schleser, Markus; Mokrov, Oleg; Zabirov, Alexander

2011-06-01

A two dimensional transient numerical analysis and computational module for simulation of electrical and thermal characteristics during electrode melting and metal transfer involved in Gas-Metal-Arc-Welding (GMAW) processes is presented. Solution of non-linear transient heat transfer equation is carried out using a control volume finite difference technique. The computational module also includes controlling and regulation algorithms of industrial welding power sources. The simulation results are the current and voltage waveforms, mean voltage drops at different parts of circuit, total electric power, cathode, anode and arc powers and arc length. We describe application of the model for normal process (constant voltage) and for pulsed processes with U/I and I/I-modulation modes. The comparisons with experimental waveforms of current and voltage show that the model predicts current, voltage and electric power with a high accuracy. The model is used in simulation package SimWeld for calculation of heat flux into the work-piece and the weld seam formation. From the calculated heat flux and weld pool sizes, an equivalent volumetric heat source according to Goldak model, can be generated. The method was implemented and investigated with the simulation software SimWeld developed by the ISF at RWTH Aachen University.

Study of the collector/heat pipe cooled externally configured thermionic diode

NASA Technical Reports Server (NTRS)

1973-01-01

A collector/heat pipe cooled, externally configured (heated) thermionic diode module was designed for use in a laboratory test to demonstrate the applicability of this concept as the fuel element/converter module of an in-core thermionic electric power source. During the course of the program, this module evolved from a simple experimental mock-up into an advanced unit which was more reactor prototypical. Detailed analysis of all diode components led to their engineering design, fabrication, and assembly, with the exception of the collector/heat pipe. While several designs of high power annular wicked heat pipes were fabricated and tested, each exhibited unexpected performance difficulties. It was concluded that the basic cause of these problems was the formation of crud which interfered with the liquid flow in the annular passage of the evaporator region.

Numerical study on the thermal management system of a liquid metal battery module

NASA Astrophysics Data System (ADS)

Guo, Zhenlin; Xu, Cheng; Li, Wei; Zhu, Fangfang; Li, Haomiao; Wang, Kangli; Cheng, Shijie; Jiang, Kai

2018-07-01

Liquid metal battery (LMB), with three-liquid-layer structure and high operating temperature (300-700 °C), is a newly emerging technology for large scale energy storage applications. A thermal management system is critical to achieve satisfied LMB performance and extend the life of batteries. In this work, an improved coupling model composing of a 3D heat-transfer model and a 1D electrochemical model is developed for the thermal analysis of a Li||Sb-Sn LMBs module (5.5 kWh). Key results including transient values, the contribution ratio of heat sources, temperature homogeneity and distribution, as well as the energy efficiency of the battery module, are presented. Based on the coupling model, the changeable-power-heating mode, sand filling material and vacuum insulation are further proposed to achieve the high energy efficiency and optimal performance of the LMBs module. Moreover, the LMBs module can achieve "self-heating" when operated at 0.2 C charge/discharge, under the vacuum insulation (0.01 W m-1 K-1 thermal conductivity, 100 mm thickness), requiring no external heating to keep the batteries at operating temperature.

Infrasound induced instability by modulation of condensation process in the atmosphere.

PubMed

Naugolnykh, Konstantin; Rybak, Samuil

2008-12-01

A sound wave in supersaturated water vapor can modulate both the process of heat release caused by condensation, and subsequently, as a result, the resonance interaction of sound with the modulated heat release provides sound amplification. High-intensity atmospheric perturbations such as cyclones and thunderstorms generate infrasound, which is detectable at large distances from the source. The wave-condensation instability can lead to variation in the level of infrasound radiation by a developing cyclone, and this can be as a precursor of these intense atmospheric events.

World Energy Projection System Plus Model Documentation: District Heat Module

EIA Publications

2017-01-01

This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) District Heat Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

CADDIS Volume 2. Sources, Stressors and Responses: Temperature - Figure 1. Major Heat Flux Processes in Streams

EPA Pesticide Factsheets

Introduction to the temperature module, when to list temperature as a candidate cause, ways to measure temperature, simple and detailed conceptual diagrams for temperature, temperature module references and literature reviews.

Lunar Surface Stirling Power Systems Using Am-241

NASA Technical Reports Server (NTRS)

Schmitz, Paul C.; Penswick, L. Barry; Shaltens, Richard K.

2009-01-01

For many years NASA has used the decay of Pu-238 (in the form of the General Purpose Heat Source (GPHS)) as a heat source for Radioisotope Thermoelectric Generators (RTG), which have provided electrical power for many NASA missions. While RTG's have an impressive reliability record for the missions in which they have been used, their relatively low thermal to electric conversion efficiency (-5% efficiency) and the scarcity of Plutoinium-238 (Pu-238) has led NASA to consider other power conversion technologies. NASA is considering returning both robotic and human missions to the lunar surface and, because of the long lunar nights (14 earth days) isotope power systems are an attractive candidate to generate electrical power. NASA is currently developing the Advanced Stirling Radioisotope Generator (ASRG) as a candidate higher efficiency power system that produces greater than 160 watts with 2 GPHS modules at the beginning of life (BOL) (-30% efficiency). The ASRG uses the same Pu-238 GPHS modules, which are used in RTG, but by coupling them to a Stirling convertor provides a 4-fold reduction in the number of GPHS modules. This study considers the use of Americium 241 (Am-241) as a substitute for the Pu-238 in Stirling convertor based Radioisotope Power Systems (RPS) for power levels from 1 O's of watts to 5 kWe. The Am-241 is used as a replacement for the Pu-238 in GPHS modules. Depending on power level, different Stirling heat input and removal systems are modeled. It was found that substituting Am-241 GPHS modules into the ASRG reduces power output by about 1/5 while maintaining approximately the same system mass. In order to obtain the nominal 160 watts electrical output of the Pu-238 ASRG requires 10 Am-241 GPHS modules. Higher power systems require changing from conductive coupling heat input and removal from the Stirling convertor to either pumped loops or heat pipes. Liquid metal pumped loops are considered as the primary heat transportation on the hot end and water pumped loop/heat pipe radiator is considered for the heat rejection side for power levels above 1 kWe.

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

Rice, C Keith; Uselton, Robert B.; Shen, Bo

A residential-sized dual air-source integrated heat pump (AS-IHP) concept is under development in partnership between ORNL and a manufacturer. The concept design consists of a two-stage air-source heat pump (ASHP) coupled on the air distribution side with a separate novel water heating/dehumidification (WH/DH) module. The motivation for this unusual equipment combination is the forecast trend for home sensible loads to be reduced more than latent loads. Integration of water heating with a space dehumidification cycle addresses humidity control while performing double-duty. This approach can be applied to retrofit/upgrade applications as well as new construction. A WH/DH module capable of ~1.47more » L/h water removal and ~2 kW water heating capacity was assembled by the manufacturer. A heat pump system model was used to guide the controls design; lab testing was conducted and used to calibrate the models. Performance maps were generated and used in a TRNSYS sub-hourly simulation to predict annual performance in a well-insulated house. Annual HVAC/WH energy savings of ~35% are predicted in cold and hot-humid U.S. climates compared to a minimum efficiency baseline.« less

Method and apparatus for aerosol particle absorption spectroscopy

DOEpatents

Campillo, Anthony J.; Lin, Horn-Bond

1983-11-15

A method and apparatus for determining the absorption spectra, and other properties, of aerosol particles. A heating beam source provides a beam of electromagnetic energy which is scanned through the region of the spectrum which is of interest. Particles exposed to the heating beam which have absorption bands within the band width of the heating beam absorb energy from the beam. The particles are also illuminated by light of a wave length such that the light is scattered by the particles. The absorption spectra of the particles can thus be determined from an analysis of the scattered light since the absorption of energy by the particles will affect the way the light is scattered. Preferably the heating beam is modulated to simplify the analysis of the scattered light. In one embodiment the heating beam is intensity modulated so that the scattered light will also be intensity modulated when the particles absorb energy. In another embodiment the heating beam passes through an interferometer and the scattered light reflects the Fourier Transform of the absorption spectra.

Effects of different excitation waveforms on detection and characterisation of delamination in PV modules by active infrared thermography

NASA Astrophysics Data System (ADS)

Sinha, Archana; Gupta, Rajesh

2017-10-01

Delamination significantly affects the performance and reliability of photovoltaic (PV) modules. Recently, an active infrared thermography approach using step heating has been exploited for the detection and characterisation of delamination in PV modules. However, step heating takes longer observation time and causes overheating problems. This paper presents the effects of different thermal excitation waveforms namely rectangular, half-sine and short pulse, on the detection and characterisation of delamination in PV module by experiments and simulations. For simulation, a 3-dimensional electro-thermal model of heat conduction, based on resistance-capacitance network approach, has been exploited to study the variation in maximum thermal contrast and peak contrast time with the delamination thickness and heating parameters. Results show that the rectangular waveform provides better detection of delamination due to higher absolute contrast, while the half-sine waveform allows better characterisation of delamination in the PV modules with low-cost and low-power heat source. The high-energy short pulse enabled quick visualisation of delamination, but has limited practical implementation. The advantages and limitations of each waveform have been highlighted to assess the specific requirement for appropriate choice in the non-destructive thermographic inspection of delamination in PV modules at the manufacturing units or outdoor fields.

A Novel Approach to Thermal Design of Solar Modules: Selective-Spectral and Radiative Cooling

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

Sun, Xingshu; Dubey, Rajiv; Chattopadhyay, Shashwata

2016-11-21

For commercial solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20-30 degrees C higher than the ambient. In the long run, extreme self-heating may erode efficiency and shorten lifetime, thereby, dramatically reducing the total energy output by almost ~10% Therefore, it is critically important to develop effective and practical cooling methods to combat PV self-heating. In this paper, we explore two fundamental sources of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical and thermal properties of the solar module to eliminatemore » the parasitic absorption (selective-spectral cooling) and enhance the thermal emission to the cold cosmos (radiative cooling). The proposed technique should cool the module by ~10 degrees C, to be reflected in significant long-term energy gain (~ 3% to 8% over 25 years) for PV systems under different climatic conditions.« less

Multi Station Frequency Response and Polarization of ELF/VLF Signals Generated via Ionospheric Modification

NASA Astrophysics Data System (ADS)

Maxworth, Ashanthi; Golkowski, Mark; University of Colorado Denver Team

2013-10-01

ELF/VLF wave generation via HF modulated ionospheric heating has been practiced for many years as a unique way to generate waves in the ELF/VLF band (3 Hz - 30 kHz). This paper presents experimental results and associated theoretical modeling from work performed at the High Frequency Active Auroral Research Program (HAARP) facility in Alaska, USA. An experiment was designed to investigate the modulation frequency dependence of the generated ELF/VLF signal amplitudes and polarization at multiple sites at distances of 37 km, 50 km and 99 km from the facility. While no difference is observed for X mode versus O mode modulation of the heating wave, it is found that ELF/VLF amplitude and polarization as a function of modulated ELF/VLF frequency is different for each site. An ionospheric heating code is used to determine the primary current sources leading to the observations.

Numerical study of the generation and propagation of ultralow-frequency waves by artificial ionospheric F region modulation at different latitudes

NASA Astrophysics Data System (ADS)

Xu, Xiang; Zhou, Chen; Shi, Run; Ni, Binbin; Zhao, Zhengyu; Zhang, Yuannong

2016-09-01

Powerful high-frequency (HF) radio waves can be used to efficiently modify the upper-ionospheric plasmas of the F region. The pressure gradient induced by modulated electron heating at ultralow-frequency (ULF) drives a local oscillating diamagnetic ring current source perpendicular to the ambient magnetic field, which can act as an antenna radiating ULF waves. In this paper, utilizing the HF heating model and the model of ULF wave generation and propagation, we investigate the effects of both the background ionospheric profiles at different latitudes in the daytime and nighttime ionosphere and the modulation frequency on the process of the HF modulated heating and the subsequent generation and propagation of artificial ULF waves. Firstly, based on a relation among the radiation efficiency of the ring current source, the size of the spatial distribution of the modulated electron temperature and the wavelength of ULF waves, we discuss the possibility of the effects of the background ionospheric parameters and the modulation frequency. Then the numerical simulations with both models are performed to demonstrate the prediction. Six different background parameters are used in the simulation, and they are from the International Reference Ionosphere (IRI-2012) model and the neutral atmosphere model (NRLMSISE-00), including the High Frequency Active Auroral Research Program (HAARP; 62.39° N, 145.15° W), Wuhan (30.52° N, 114.32° E) and Jicamarca (11.95° S, 76.87° W) at 02:00 and 14:00 LT. A modulation frequency sweep is also used in the simulation. Finally, by analyzing the numerical results, we come to the following conclusions: in the nighttime ionosphere, the size of the spatial distribution of the modulated electron temperature and the ground magnitude of the magnetic field of ULF wave are larger, while the propagation loss due to Joule heating is smaller compared to the daytime ionosphere; the amplitude of the electron temperature oscillation decreases with latitude in the daytime ionosphere, while it increases with latitude in the nighttime ionosphere; both the electron temperature oscillation amplitude and the ground ULF wave magnitude decreases as the modulation frequency increases; when the electron temperature oscillation is fixed as input, the radiation efficiency of the ring current source is higher in the nighttime ionosphere than in the daytime ionosphere.

Vibration Method for Tracking the Resonant Mode and Impedance of a Microwave Cavity

NASA Technical Reports Server (NTRS)

Barmatz, M.; Iny, O.; Yiin, T.; Khan, I.

1995-01-01

A vibration technique his been developed to continuously maintain mode resonance and impedance much between a constant frequency magnetron source and resonant cavity. This method uses a vibrating metal rod to modulate the volume of the cavity in a manner equivalent to modulating an adjustable plunger. A similar vibrating metal rod attached to a stub tuner modulates the waveguide volume between the source and cavity. A phase sensitive detection scheme determines the optimum position of the adjustable plunger and stub turner during processing. The improved power transfer during the heating of a 99.8% pure alumina rod was demonstrated using this new technique. Temperature-time and reflected power-time heating curves are presented for the cases of no tracking, impedance tracker only, mode tracker only and simultaneous impedance and mode tracking. Controlled internal melting of an alumina rod near 2000 C using both tracking units was also demonstrated.

Design and performance of radioisotope space power systems based on OSC multitube AMTEC converter designs

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

Schock, A.; Noravian, H.; Or, C.

1997-12-31

This paper extends the analytical procedure described in another paper in these proceedings to analyze a variety of compact and light-weight OSC-designed radioisotope-heated generators. Those generators employed General Purpose Heat Source (GPHS) modules and a converter containing sixteen AMTEC cells of OSC`s revised five-tube design with enhanced cell wall reflectivity described in a companion paper in these proceedings. OSC found that the performance of the generator is primarily a function of the thermal insulation between the outside of the generator`s 16 cells and the inside of its wall. After examining a variety of insulation options, it was found that themore » generator`s performance is optimized by employing a hybrid insulation system, in which the space between the cells is filled with fibrous Min-K insulation, and the generator walls are lined with tapered (i.e., graded-length) multifoil insulation. The OSC design results in a very compact generator, with eight AMTEC cells on each end of the heat source stack. The choice of the five-tube cells makes it possible to expand the BASE tube diameter without increasing the cell diameter. This is important because the eight cells mate well with the stacked GPHS modules. The OSC generator design includes a compliant heat source support and preload arrangement, to hold the heat source modules together during launch, and to maintain thermal contact conductance at the generator`s interfaces despite creep relaxation of its housing. The BOM and EOM (up to 15 years) performances of the revised generators were analyzed for two and three GPHS modules, both for fresh fuel and for aged fuel left over from a spare RTG (Radioisotope Thermoelectric Generator) fueled in 1982. The resulting power outputs were compared with JPL`s latest EOM power demand goals for the Pluto Express and Europa Orbiter missions, and with the generic goals of DOE`s Advanced Radioisotope Power System (ARPS) study. The OSC AMTEC designs yielded system efficiencies three to four times as high as present-generation RTGs.« less

ULF Generation by Modulated Ionospheric Heating

NASA Astrophysics Data System (ADS)

Chang, C.; Labenski, J.; Wallace, T.; Papadopoulos, K.

2013-12-01

Modulated ionospheric heating experiments designed to generate ULF waves using the HAARP heater have been conducted since 2007. Artificial ULF waves in the Pc1 frequency range were observed from space and by ground induction magnetometers located in the vicinity of the heater as well as at long distances. Two distinct generation mechanisms of artificial ULF waves were identified. The first was electroject modulation under geomagnetically disturbed conditions. The second was pressure modulation in the E and F regions of the ionosphere under quiet conditions. Ground detections of ULF waves near the heater included both Shear Alfven waves and Magnetosonic waves generated by electrojet and/or pressure modulations. Distant ULF detections involved Magnetosonic wave propagation in the Alfvenic duct with pressure modulation as the most likely source. Summary of our observations and theoretical interpretations will be presented at the meeting. We would like to acknowledge the support provided by the staff at the HAARP facility during our ULF experiments.

Compact thermoelectric converter systems technology

NASA Technical Reports Server (NTRS)

1973-01-01

A schematic of the developed tubular thermoelectric module is shown. It consists of alternate washers of n- and p-type lead telluride, separated by thin natural mica washers. Electrical continuity within the circuit is accomplished by cylindrical conductor rings located at the I.D. and O.D. of the lead telluride washers. The conductor rings are also separated by the same mica which separate the lead telluride washers. The result is a radially serpentine current path along the length of the module. The circuit is isolated from the structural claddings by thin sleeves of boron nitride. Circuit containment and heat transfer surfaces are provided by the inner and outer cladding, heat being transferred from a heat source at the inner clad, conducted radially outward through the lead telluride to the outer clad where the waste heat is removed by a heat rejection system.

Results of a First Generation Propellant Energy Source Module Testing: Non-Nuclear Testing of Fission System

NASA Technical Reports Server (NTRS)

VanDyke, Melissa; Godfroy, Tom; Houts, Mike; Dickens, Ricky; Dobson, Chris; Pederson, Kevin; Reid, Bob

1999-01-01

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on the Module Unfueled Thermal- hydraulic Test (MUTT) article has been performed at the Marshall Space Flight Center. This paper discusses the results of these experiments to date, and describes the additional testing that will be performed. Recommendations related to the design of testable space fission power and propulsion systems are made.

Electrical Energy Harvesting from Thermal Energy with Converged Infrared Light

NASA Astrophysics Data System (ADS)

Goh, S. Y.; Kok, S. L.

2017-06-01

Photovoltaics (PV) cell is a common energy harvester that had been used to harvest solar energy and convert it into electrical energy. However, the vast energy from the spectrum of sunlight is not fully harvested. Therefore, thermoelectric (TE) module that harvest electrical energy from heat is being proposed in this paper. Generally, the part of the sunlight spectrum that induce heat is in the spectrum band of infrared (IR). For the experimental set-up in this paper, infrared (IR) light bulb was being used to simulate the IR spectrum band of the sunlight. In order to maximize the heat energy collection, a convex lens was being used to converge the IR light and therefore focused the heat on an aluminium sheet and heat sink which was placed on top of the hot side of the TE module. The distance between convex lens and IR light bulb is varying in between 10cm and 55cm and the reading was taken at an interval of 5cm. Firstly, the temperature of the IR light and converged IR light were recorded and plotted in graph. The graph showed that the temperature of the converged IR light bulb is higher than the IR light bulb. Lastly, the voltage and power output of the TE module with different heat source was compared. The output voltage and power of the TE module increased inverse proportional to the distance between IR light bulb and TE module.

Observations of disk-shaped bodies in free flight at terminal velocity

NASA Technical Reports Server (NTRS)

Vorreiter, J. W.; Tate, D. L.

1973-01-01

Ten disk-shaped models of a proposed nuclear heat source module were released from an aircraft and observed by radar. The initial launch attitude, spin rate, and mass of the models were varied. Significant differences were observed in the mode of flight and terminal velocity among models of different mass and launch attitudes. The data were analyzed to yield lift and drag coefficients as a function of Reynolds number. The total sea-level velocity of the models was found to be well correlated as a function of mass per unit frontal area. The demonstrated terminal velocity of the modular disk heat source, about 27 m/sec for this specific design, is only 33% of that of existing heat source designs.

Method and apparatus for millimeter-wave detection of thermal waves for materials evaluation

DOEpatents

Gopalsami, Nachappa; Raptis, Apostolos C.

1991-01-01

A method and apparatus for generating thermal waves in a sample and for measuring thermal inhomogeneities at subsurface levels using millimeter-wave radiometry. An intensity modulated heating source is oriented toward a narrow spot on the surface of a material sample and thermal radiation in a narrow volume of material around the spot is monitored using a millimeter-wave radiometer; the radiometer scans the sample point-by-point and a computer stores and displays in-phase and quadrature phase components of thermal radiations for each point on the scan. Alternatively, an intensity modulated heating source is oriented toward a relatively large surface area in a material sample and variations in thermal radiation within the full field of an antenna array are obtained using an aperture synthesis radiometer technique.

High Frequency Resolution TOA Analysis for ELF/VLFWave Generation Experiments at HAARP

NASA Astrophysics Data System (ADS)

Ruddle, J. D.; Moore, R. C.

2014-12-01

Modulated HF heating of the ionosphere in the presence of natural ionospheric current sources has been used as a method to generate electromagnetic ELF/VLF waves since the 1970's. In the ~1-5 kHz band, the amplitude and phase of the received ELF/VLF signal depends on the amplitude and phase of the conductivity modulation generated throughout the HF-heated ionospheric body, as well as on the signal propagation parameters (i.e., the attenuation and phase constants) between each of the current sources and the receiver. Recent signal processing advances have produced an accurate ELF/VLF time-of-arrival (TOA) analysis technique that differentiates line-of-sight and ionospherically-reflected signal components, determining the amplitude and phase of each component observed at the receiver. This TOA method requires a wide bandwidth (> 2.5 kHz) and therefore is relatively insensitive to the frequency-dependent nature of ELF/VLF wave propagation. In this paper, we present an improved ELF/VLF TOA method that is capable of providing high frequency resolution. The new analysis technique is applied to experimental observations of ELF/VLF signals generated by modulated heating at HAARP. We present measurements of the amplitude and phase of the received ELF/VLF signal as a function of frequency and compare the results with the predictions of an HF heating model.

Maximum Potential of the Car Cabin Temperature in the Outdoor Parking Conditions as a Source of Energy in Thermoelectric Generator

NASA Astrophysics Data System (ADS)

Sunawar, A.; Garniwa, I.

2017-03-01

Cars using the principle of converting heat energy into mechanical energy, but a lot of wasted heat energy not entirely transformed into mechanical energy, studies have been conducted that converts the heat energy into electrical energy using the principle thermoelectrically. However, there are many other energies that can be harnessed from the car, such as when the car is parked in the sun or driving in the heat of the sun, the temperature in the cabin can reach 80 degrees Celsius. The heat can be harmful to humans and the children immediately into the vehicle, as well as for the goods stored in the cabin if it contains toxins can evaporate because of the heat and dangerous. The danger can be prevented by reducing the heat in the cabin and transform into other forms of energy such as electricity. By providing a temperature difference of 40 degrees on the cold side of the module can be acquired electricity thermoelectrically up to 0.17W for one of its module, if it is made a module block the energy produced is enough to lower the temperature and charge batteries for further cooling. This study will use experiment method to get the maximum drop in temperature in the car cabin

Miniaturized radioisotope solid state power sources

NASA Astrophysics Data System (ADS)

Fleurial, J.-P.; Snyder, G. J.; Patel, J.; Herman, J. A.; Caillat, T.; Nesmith, B.; Kolawa, E. A.

2000-01-01

Electrical power requirements for the next generation of deep space missions cover a wide range from the kilowatt to the milliwatt. Several of these missions call for the development of compact, low weight, long life, rugged power sources capable of delivering a few milliwatts up to a couple of watts while operating in harsh environments. Advanced solid state thermoelectric microdevices combined with radioisotope heat sources and energy storage devices such as capacitors are ideally suited for these applications. By making use of macroscopic film technology, microgenrators operating across relatively small temperature differences can be conceptualized for a variety of high heat flux or low heat flux heat source configurations. Moreover, by shrinking the size of the thermoelements and increasing their number to several thousands in a single structure, these devices can generate high voltages even at low power outputs that are more compatible with electronic components. Because the miniaturization of state-of-the-art thermoelectric module technology based on Bi2Te3 alloys is limited due to mechanical and manufacturing constraints, we are developing novel microdevices using integrated-circuit type fabrication processes, electrochemical deposition techniques and high thermal conductivity substrate materials. One power source concept is based on several thermoelectric microgenerator modules that are tightly integrated with a 1.1W Radioisotope Heater Unit. Such a system could deliver up to 50mW of electrical power in a small lightweight package of approximately 50 to 60g and 30cm3. An even higher degree of miniaturization and high specific power values (mW/mm3) can be obtained when considering the potential use of radioisotope materials for an alpha-voltaic or a hybrid thermoelectric/alpha-voltaic power source. Some of the technical challenges associated with these concepts are discussed in this paper. .

Ultrafast Modulation and Switching of Quantum-Well Lasers using Terahertz Fields

NASA Technical Reports Server (NTRS)

Ning, Cun-Zheng; Hughes, S.; Citrin, D.; Saini, Subhash (Technical Monitor)

1998-01-01

Modulation and switching of semiconductor lasers are important for laser-based information technology. Typically the speed of modulation and switching is limited by interband processes such as stimulated and spontaneous recombinations which occur on a nanosecond time scale. This is why the diode laser modulation has been restricted to tens of GHz. Modulation at higher speed is highly desirable as the information technology enters into the so-called tera-era. In this paper, we study the possibility of utilizing THz-field-induced plasma heating to modulate quantum-well lasers. This is a timely study since, with the advancement of THz solid-state sources and free-electron lasers, THz physics and related technology is currently coming out of its infancy. The investigation of interplaying THz and optical fields is also of intruiging fundamental interest. First, we introduce theoretical plasma heating results for the quantum-well optical amplifier in the presense of an intense half-cycle THz pulse. The heated carrier distributions are then utilized to calculate the THz-pulse-induced change in refractive index and gain profile. Since the electron-hole-plasma is heated using intraband transitions, we circumvent the usual complications due to an overall change in density, and the nonlinear recovery is governed solely by the carrier-LO-phonon interactions, typically 5 ps for a complete recovery. This procedure implies THz and sub-THz switching and recovery rates, respectively; using either gain modulation or index modulation. Plasma heating via steady-state THz fields is also studied. Finally, numerical simulation of a coupled set of equations to investigate the THz modulation based on a simplified model for quantum-well lasers is presented. Our results show that a semiconductor laser can be modulated at up to 1 THz with little distortion with a THz field amplitude at the order of a few kV/cm. Laser responses to a change in THz frequency will be shown. Constraints, practicalities, and applications will be discussed.

Estimation and harvesting of human heat power for wearable electronic devices

NASA Astrophysics Data System (ADS)

Dziurdzia, P.; Brzozowski, I.; Bratek, P.; Gelmuda, W.; Kos, A.

2016-01-01

The paper deals with the issue of self-powered wearable electronic devices that are capable of harvesting free available energy dissipated by the user in the form of human heat. The free energy source is intended to be used as a secondary power source supporting primary battery in a sensor bracelet. The main scope of the article is a presentation of the concept for a measuring setup used to quantitative estimation of heat power sources in different locations over the human body area. The crucial role in the measurements of the human heat plays a thermoelectric module working in the open circuit mode. The results obtained during practical tests are confronted with the requirements of the dedicated thermoelectric generator. A prototype design of a human warmth energy harvester with an ultra-low power DC-DC converter based on the LTC3108 circuit is analysed.

FPGA Techniques Based New Hybrid Modulation Strategies for Voltage Source Inverters

PubMed Central

Sudha, L. U.; Baskaran, J.; Elankurisil, S. A.

2015-01-01

This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switching and carrier based pulse width modulation methods. Thus, the harmonic pollution in the power system will be reduced and the power quality will be augmented with better harmonic profile for a target fundamental output voltage. The proposed modulation strategies are simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor. The feasibility of these modulation strategies is authenticated through simulation and experimental results. PMID:25821852

Advanced Soldier Thermoelectric Power System for Power Generation from Battlefield Heat Sources

DTIC Science & Technology

2010-09-01

Figure 6.10 TE Module with Microtherm Added Around & Between Legs ............................................................... 57  Figure 6.11 Short... Microtherm ® insulation, 2.6 (W) of heater power was required to maintain a temperature of 400 ºC. This is an indication of the losses in the system...side of the module to the cold plate.  Pour in Microtherm to insulate the module.  Make sure to clean all insulation from the hot side electrodes

Influence of heat and vibration on the movement of the northern fowl mite (Acari: Macronyssidae).

PubMed

Owen, Jeb P; Mullens, Bradley A

2004-09-01

Heat and vibration are common host-generated cues that ectoparasites use to orient to hosts. Three experiments evaluated effects of heat and vibration on the movement of northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago). Individual arrested mites in an isolation chamber always initiated movement (walking) after substrate vibration (7.8-min walking duration), but only initiated movement 50% of the time (2.8-min walking duration) upon exposure to a 3 degrees C heat fluctuation. Heat fluctuation in combination with vibration extended the period of activity by approximately 50% (11.6-min walking duration) compared with activity initiated by vibration alone. Mites with longer time off-host moved for shorter durations. In a choice test, individual mites consistently moved closer to a 35 degrees C heat source 1 or 6 mm away, but not to a heat source 11 mm away. In a circular arena, mites were able to orient accurately to a 35 degrees C heat source and reached the arena edge almost 4 times faster (11.2 s) than mites without a heat source (41.2 s). These results suggest that northern fowl mite is capable of directed thermo-orientation, as well as modulation of activity depending on the type of sensory information perceived. The adaptive significance of this orientation for a "permanent" ectoparasite is discussed.

Ground and Satellite Observations of ULF Waves Artificially Produced by HAARP

NASA Astrophysics Data System (ADS)

Chang, C.; Labenski, J.; Shroff, H.; Doxas, I.; Papadopoulos, D.; Milikh, G.; Parrot, M.

2008-12-01

Modulated ionospheric heating at ULF frequencies using the HAARP heater was performed from April 28 to May 3, 2008 (http://www.haarp.alaska.edu). Simultaneous ground-based ULF measurements were made locally at Gakona, AK and at Lake Ozette, WA that is 2000 km away. The ground-based results showed that ULF amplitudes measured at Gakona are mostly proportional to the electrojet strength above HAARP, indicating electrojet modulation to be the source of the local ULF waves. However, the timing of ULF events recorded at Lake Ozette did not correlated with the electrojet strength at Gakona, indicating that modulation of F region pressure is the more likely source for distant ULF waves. These observations are consistent with the theoretical understanding that ULF waves generated by current modulation are shear Alfven waves propagating along the magnetic field line, thus at high latitude their observations are limited to the vicinity of the heated spot. On the other hand, propagation of ULF waves at significant lateral distances requires generation of magnetosonic waves since they are the only mode that propagates isotropically and can thus couple efficiently in the Alfvenic duct. In addition to ground-based observations, the DEMETER satellite also provided space measurements of the heating effects during its passes over HAARP. The DEMETER results showed direct detection of HAARP ULF waves at 0.1 Hz. Moreover, density dips were observed every time HAARP was operated at CW mode, which provides clear evidence of duct formation by direct HF heating at F peak. Details of these results will be presented at the meeting. We would like to acknowledge the support provided by the HAARP facility during our ULF experiments.

Thermoelectric Exhaust Heat Recovery with Heat Pipe-Based Thermal Control

NASA Astrophysics Data System (ADS)

Brito, F. P.; Martins, Jorge; Hançer, Esra; Antunes, Nuno; Gonçalves, L. M.

2015-06-01

Heat pipe (HP)-based heat exchangers can be used for very low resistance heat transfer between a hot and a cold source. Their operating temperature depends solely on the boiling point of their working fluid, so it is possible to control the heat transfer temperature if the pressure of the HP can be adjusted. This is the case of the variable conductance HPs (VCHP). This solution makes VCHPs ideal for the passive control of thermoelectric generator (TEG) temperature levels. The present work assesses, both theoretically and experimentally, the merit of the aforementioned approach. A thermal and electrical model of a TEG with VCHP assist is proposed. Experimental results obtained with a proof of concept prototype attached to a small single-cylinder engine are presented and used to validate the model. It was found that the HP heat exchanger indeed enables the TEG to operate at a constant, optimal temperature in a passive and safe way, and with a minimal overall thermal resistance, under part load, it effectively reduces the active module area without deprecating the temperature level of the active modules.

Thermal imaging of spin Peltier effect

NASA Astrophysics Data System (ADS)

Daimon, Shunsuke; Iguchi, Ryo; Hioki, Tomosato; Saitoh, Eiji; Uchida, Ken-Ichi

2016-12-01

The Peltier effect modulates the temperature of a junction comprising two different conductors in response to charge currents across the junction, which is used in solid-state heat pumps and temperature controllers in electronics. Recently, in spintronics, a spin counterpart of the Peltier effect was observed. The `spin Peltier effect' modulates the temperature of a magnetic junction in response to spin currents. Here we report thermal imaging of the spin Peltier effect; using active thermography technique, we visualize the temperature modulation induced by spin currents injected into a magnetic insulator from an adjacent metal. The thermal images reveal characteristic distribution of spin-current-induced heat sources, resulting in the temperature change confined only in the vicinity of the metal/insulator interface. This finding allows us to estimate the actual magnitude of the temperature modulation induced by the spin Peltier effect, which is more than one order of magnitude greater than previously believed.

Safety assessment of near infrared light emitting diodes for diffuse optical measurements

PubMed Central

Bozkurt, Alper; Onaral, Banu

2004-01-01

Background Near infrared (NIR) light has been used widely to monitor important hemodynamic parameters in tissue non-invasively. Pulse oximetry, near infrared spectroscopy, and diffuse optical tomography are examples of such NIR light-based applications. These and other similar applications employ either lasers or light emitting diodes (LED) as the source of the NIR light. Although the hazards of laser sources have been addressed in regulations, the risk of LED sources in such applications is still unknown. Methods Temperature increase of the human skin caused by near infrared LED has been measured by means of in-vivo and in-vitro experiments. Effects of the conducted and radiated heat in the temperature increase have been analyzed separately. Results Elevations in skin temperature up to 10°C have been observed. The effect of radiated heat due to NIR absorption is low – less than 0.5°C – since emitted light power is comparable to the NIR part of sunlight. The conducted heat due to semiconductor junction of the LED can cause temperature increases up to 9°C. It has been shown that adjusting operational parameters by amplitude modulating or time multiplexing the LED decreases the temperature increase of the skin significantly. Conclusion In this study, we demonstrate that the major risk source of the LED in direct contact with skin is the conducted heat of the LED semiconductor junction, which may cause serious skin burns. Adjusting operational parameters by amplitude modulating or time multiplexing the LED can keep the LED within safe temperature ranges. PMID:15035670

Realistic Development and Testing of Fission System at a Non-Nuclear Testing Facility

NASA Technical Reports Server (NTRS)

Godfroy, Tom; VanDyke, Melissa; Dickens, Ricky; Pedersen, Kevin; Lenard, Roger; Houts, Mike

2000-01-01

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on a module has been performed at the Marshall Space Flight Center in the Propellant Energy Source Testbed (PEST). This paper discusses the experimental facilities and equipment used for performing resistance heated tests. Recommendations are made for improving non-nuclear test facilities and equipment for simulated testing of nuclear systems.

Realistic development and testing of fission systems at a non-nuclear testing facility

NASA Astrophysics Data System (ADS)

Godfroy, Tom; van Dyke, Melissa; Dickens, Ricky; Pedersen, Kevin; Lenard, Roger; Houts, Mike

2000-01-01

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on a module has been performed at the Marshall Space Flight Center in the Propellant Energy Source Testbed (PEST). This paper discusses the experimental facilities and equipment used for performing resistance heated tests. Recommendations are made for improving non-nuclear test facilities and equipment for simulated testing of nuclear systems. .

A general circulation model study of the solar and QBO modulation of the stratospheric circulation during the northern hemisphere winter

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

Kodera, Kunihiko; Chiba, Masaru; Shibata, Kiyotaka

1991-07-01

A general circulation model has been used to study the modulation of north-polar temperatures during winter by both solar activity and the equatorial quasi-biennial oscillation (QBO). The variation of solar activity was simulated by changing the heating rate due to the absorption of ultraviolet (UV) radiation by ozone, while the QBO zonal wind fields were reproduced by incorporating zonal-momentum sources in the equatorial stratosphere. A total of 10 experiments were conducted by changing the heating rate from 70 to 110% for each of the simulated QBO easterly and westerly cases. The results of the numerical experiments show modulation effects similarmore » to those found by Labitzke (1987) in the 30-mb temperatures at the North Pole.« less

Direct and quantitative broadband absorptance spectroscopy with multilayer cantilever probes

DOEpatents

Hsu, Wei-Chun; Tong, Jonathan Kien-Kwok; Liao, Bolin; Chen, Gang

2015-04-21

A system for measuring the absorption spectrum of a sample is provided that includes a broadband light source that produces broadband light defined within a range of an absorptance spectrum. An interferometer modulates the intensity of the broadband light source for a range of modulation frequencies. A bi-layer cantilever probe arm is thermally connected to a sample arm having at most two layers of materials. The broadband light modulated by the interferometer is directed towards the sample and absorbed by the sample and converted into heat, which causes a temperature rise and bending of the bi-layer cantilever probe arm. A detector mechanism measures and records the deflection of the probe arm so as to obtain the absorptance spectrum of the sample.

Investigation of the radiation properties of magnetospheric ELF waves induced by modulated ionospheric heating

NASA Astrophysics Data System (ADS)

Wang, Feng; Ni, Binbin; Zhao, Zhengyu; Zhao, Shufan; Zhao, Guangxin; Wang, Min

2017-05-01

Electromagnetic extremely low frequency (ELF) waves play an important role in modulating the Earth's radiation belt electron dynamics. High-frequency (HF) modulated heating of the ionosphere acts as a viable means to generate artificial ELF waves. The artificial ELF waves can reside in two different plasma regions in geo-space by propagating in the ionosphere and penetrating into the magnetosphere. As a consequence, the entire trajectory of ELF wave propagation should be considered to carefully analyze the wave radiation properties resulting from modulated ionospheric heating. We adopt a model of full wave solution to evaluate the Poynting vector of the ELF radiation field in the ionosphere, which can reflect the propagation characteristics of the radiated ELF waves along the background magnetic field and provide the initial condition of waves for ray tracing in the magnetosphere. The results indicate that the induced ELF wave energy forms a collimated beam and the center of the ELF radiation shifts obviously with respect to the ambient magnetic field with the radiation power inversely proportional to the wave frequency. The intensity of ELF wave radiation also shows a weak correlation with the size of the radiation source or its geographical location. Furthermore, the combination of ELF propagation in the ionosphere and magnetosphere is proposed on basis of the characteristics of the ELF radiation field from the upper ionospheric boundary and ray tracing simulations are implemented to reasonably calculate magnetospheric ray paths of ELF waves induced by modulated ionospheric heating.

Development of a Self-contained Heat Rejection Module (SHRM), phase 1

NASA Technical Reports Server (NTRS)

Fleming, M. L.

1976-01-01

The laboratory prototype test hardware and testing of the Self-Contained Heat Rejection Module are discussed. The purpose of the test was to provide operational and design experience for application to a flight prototype design. It also provided test evaluation of several of the actual components which were to be used in the flight prototype hardware. Several changes were made in the flight prototype design due to these tests including simpler line routing, relocation of remote operated valves to a position upstream of the expansion valves, and shock mounting of the compressor. The concept of heat rejection control by compressor speed reduction was verified and the liquid receiver, accumulator, remote control valves, oil separator and power source were demonstrated as acceptable. A procedure for mode changes between pumped fluid and vapor compression was developed.

Analysis of the energy efficiency of the implementation power electric generated modules in the CHS

NASA Astrophysics Data System (ADS)

Sukhikh, A. A.; Milyutin, V. A.; Lvova, A. M.

2017-11-01

Application on the Central heat source (CHS) local generation of electricity is primarily aimed at solving problems of own needs of electric energy that not only guarantees the independence of the work of the CHS from external electrical networks, but will prevent the stop of heat supply of consumers and defrosting heating networks in case of accidents in electrical networks caused by natural or anthropogenic factors. Open the prospects of electric power supply stand-alone objects, such commercial or industrial objects on the territory of a particular neighborhood.

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

Yazawa, Kazuaki; Shakouri, Ali

The energy conversion efficiency of today’s thermoelectric generators is significantly lower than that of conventional mechanical engines. Almost all of the existing research is focused on materials to improve the conversion efficiency. Here we propose a general framework to study the cost-efficiency trade-off for thermoelectric power generation. A key factor is the optimization of thermoelectric modules together with their heat source and heat sinks. Full electrical and thermal co-optimization yield a simple analytical expression for optimum design. Based on this model, power output per unit mass can be maximized. We show that the fractional area coverage of thermoelectric elements inmore » a module could play a significant role in reducing the cost of power generation systems.« less

Free-piston Stirling Engine system considerations for various space power applications

NASA Technical Reports Server (NTRS)

Dochat, George R.; Dhar, Manmohan

1991-01-01

Free-Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSE can be coupled with many potential heat sources (radioisotope, solar, or nuclear reactor), various heat input systems (pumped loop, heat pipe), heat rejection (pumped loop or heat pipe), and various power management and distribution systems (ac, dc, high or low voltage, and fixed or variable load). This paper reviews potential space missions that can be met using free-piston Stirling engines and discusses options of various system integration approaches. This paper briefly outlines the program and recent progress.

Design and construction of Thermoelectric Footwear Heating System for illness feet.

PubMed

Işik, Hakan

2005-12-01

In this study, a Thermoelectric Footwear Heating System is developed to use in cold weather conditions. The temperature is controlled by an analog electronic control system. Thermoelectric module is used to heat the bottom of the foot. A negative temperature coefficient (NTC) temperature sensor is used to sense the temperature and the temperature is controlled by an electronic circuit proportionally. A 3.5 V, 5000 mAh rechargeable battery is used as the power source. The temperature range of the system is between +15 degrees C and +50 degrees C. Developed footwear heating system is tested against various temperature conditions, and offer better results in the case of heating the illness feet.

Microturbine and Thermoelectric Generator Combined System: A Case Study.

PubMed

Miozzo, Alvise; Boldrini, Stefano; Ferrario, Alberto; Fabrizio, Monica

2017-03-01

Waste heat recovery is one of the suitable industrial applications of thermoelectrics. Thermoelectric generators (TEG) are used, commonly, only for low-mid size power generation systems. The low efficiency of thermoelectric modules generally does not encourage their combination with high power and temperature sources, such as gas turbines. Nevertheless, the particular features of thermoelectric technology (no moving parts, scalability, reliability, low maintenance costs) are attractive for many applications. In this work, the feasibility of the integration of a TE generator into a cogeneration system is evaluated. The cogeneration system consists of a microturbine and heat exchangers for the production of electrical and thermal energy. The aim is to improve electric power generation by using TE modules and the “free” thermal energy supplied by the cogeneration system, through the exhaust pipe of the microturbine. Three different solutions for waste heat recovery from the exhausts gas are evaluated, from the fluid dynamics and heat transfer point of view, to find out a suitable design strategy for a combined power generation system.

Cost-efficiency trade-off and the design of thermoelectric power generators.

PubMed

Yazawa, Kazuaki; Shakouri, Ali

2011-09-01

The energy conversion efficiency of today's thermoelectric generators is significantly lower than that of conventional mechanical engines. Almost all of the existing research is focused on materials to improve the conversion efficiency. Here we propose a general framework to study the cost-efficiency trade-off for thermoelectric power generation. A key factor is the optimization of thermoelectric modules together with their heat source and heat sinks. Full electrical and thermal co-optimization yield a simple analytical expression for optimum design. Based on this model, power output per unit mass can be maximized. We show that the fractional area coverage of thermoelectric elements in a module could play a significant role in reducing the cost of power generation systems.

Phase-Change Heat-Storage Module

NASA Technical Reports Server (NTRS)

Mulligan, James C.

1989-01-01

Heat-storage module accommodates momentary heating or cooling overload in pumped-liquid heat-transfer system. Large heat-storage capacity of module provided by heat of fusion of material that freezes at or near temperature desired to maintain object to be heated or cooled. Module involves relatively small penalties in weight, cost, and size and more than compensates by enabling design of rest of system to handle only average load. Latent heat of fusion of phase-change material provides large heat-storage capacity in small volume.

Energy harvesting using TEG and PV cell for low power application

NASA Astrophysics Data System (ADS)

Tawil, Siti Nooraya Mohd; Zainal, Mohd Zulkarnain

2018-02-01

A thermoelectric generator (TEG) module and photovoltaic cell (PV) were utilized to harvest energy from temperature gradients of heat sources from ambient heat and light of sun. The output of TEG and PV were connected to a power management circuit consist of step-up dc-dc converter in order to increase the output voltage to supply a low power application such as wireless communication module and the photovoltaic cell for charging an energy storage element in order to switch on a fan for cooling system of the thermoelectric generator. A switch is used as a selector to choose the input of source either from photovoltaic cell or thermoelectric generator to switch on DC-DC step-up converter. In order to turn on the DC-DC step-up converter, the input must be greater than 3V. The energy harvesting was designed so that it can be used continuously and portable anywhere. Multiple sources used in this energy harvesting system is to ensure the system can work in whatever condition either in good weather or not good condition of weather. This energy harvesting system has the potential to be used in military operation and environment that require sustainability of energy resources.

Novel Heat Controller for Thermogenerators Working on Uncontrolled Stoves

NASA Astrophysics Data System (ADS)

Juanicó, Luis E.; Rinalde, Fabián; Taglialavore, Eduardo; Molina, Marcelo

2013-07-01

This paper describes the development of a thermogenerator designed for uncontrolled firewood household stoves. It was built on BiTe thermoelectric (TE) modules, and it uses a water pot as a cooling device that also serves as a hot water source. An original heat controller was developed; it has low thermal resistance ( R) during low-power operation, but its R can be continuously increased according to the stove temperature so that the TE never overheats while its power generation is optimized.

Advanced Soldier Thermoelectric Power System for Power Generation from Battlefield Heat Sources

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

Hendricks, Terry J.; Hogan, Tim; Case, Eldon D.

2010-09-01

The U.S. military uses large amounts of fuel during deployments and battlefield operations. This project sought to develop a lightweight, small form-factor, soldier-portable advanced thermoelectric (TE) system prototype to recover and convert waste heat from various deployed military equipment (i.e., diesel generators/engines, incinerators, vehicles, and potentially mobile kitchens), with the ultimate purpose of producing power for soldier battery charging, advanced capacitor charging, and other battlefield power applications. The technical approach employed microchannel technology, a unique “power panel” approach to heat exchange/TE system integration, and newly-characterized LAST (lead-antimony-silver-telluride) and LASTT (lead-antimony-silver-tin-telluride) TE materials segmented with bismuth telluride TE materials in designingmore » a segmented-element TE power module and system. This project researched never-before-addressed system integration challenges (thermal expansion, thermal diffusion, electrical interconnection, thermal and electrical interfaces) of designing thin “power panels” consisting of alternating layers of thin, microchannel heat exchangers (hot and cold) sandwiching thin, segmented-element TE power generators. The TE properties, structurally properties, and thermal fatigue behavior of LAST and LASTT materials were developed and characterized such that the first segmented-element TE modules using LAST / LASTT materials were fabricated and tested at hot-side temperatures = 400 °C and cold-side temperatures = 40 °C. LAST / LASTT materials were successfully segmented with bismuth telluride and electrically interconnected with diffusion barrier materials and copper strapping within the module electrical circuit. A TE system design was developed to produce 1.5-1.6 kW of electrical energy using these new TE modules from the exhaust waste heat of 60-kW Tactical Quiet Generators as demonstration vehicles.« less

Optimizing an ELF/VLF Phased Array at HAARP

NASA Astrophysics Data System (ADS)

Fujimaru, S.; Moore, R. C.

2013-12-01

The goal of this study is to maximize the amplitude of 1-5 kHz ELF/VLF waves generated by ionospheric HF heating and measured at a ground-based ELF/VLF receiver. The optimization makes use of experimental observations performed during ELF/VLF wave generation experiments at the High-frequency Active Auroral Research Program (HAARP) Observatory in Gakona, Alaska. During these experiments, the amplitude, phase, and propagation delay of the ELF/VLF waves were carefully measured. The HF beam was aimed at 15 degrees zenith angle in 8 different azimuthal directions, equally spaced in a circle, while broadcasting a 3.25 MHz (X-mode) signal that was amplitude modulated (square wave) with a linear frequency-time chirp between 1 and 5 kHz. The experimental observations are used to provide reference amplitudes, phases, and propagation delays for ELF/VLF waves generated at these specific locations. The presented optimization accounts for the trade-off between duty cycle, heated area, and the distributed nature of the source region in order to construct a "most efficient" phased array. The amplitudes and phases generated by modulated heating at each location are combined in post-processing to find an optimal combination of duty cycle, heating location, and heating order.

Model documentation report: Commercial Sector Demand Module of the National Energy Modeling System

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

NONE

1998-01-01

This report documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Commercial Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated through the synthesis and scenario development based on these components. The NEMS Commercial Sector Demand Module is a simulation tool based upon economic and engineering relationships that models commercial sector energy demands at the nine Census Division level of detail for eleven distinct categories of commercial buildings. Commercial equipment selections are performed for the major fuels of electricity, natural gas,more » and distillate fuel, for the major services of space heating, space cooling, water heating, ventilation, cooking, refrigeration, and lighting. The algorithm also models demand for the minor fuels of residual oil, liquefied petroleum gas, steam coal, motor gasoline, and kerosene, the renewable fuel sources of wood and municipal solid waste, and the minor services of office equipment. Section 2 of this report discusses the purpose of the model, detailing its objectives, primary input and output quantities, and the relationship of the Commercial Module to the other modules of the NEMS system. Section 3 of the report describes the rationale behind the model design, providing insights into further assumptions utilized in the model development process to this point. Section 3 also reviews alternative commercial sector modeling methodologies drawn from existing literature, providing a comparison to the chosen approach. Section 4 details the model structure, using graphics and text to illustrate model flows and key computations.« less

Chemical methodology as a source of small-molecule checkpoint inhibitors and heat shock protein 70 (Hsp70) modulators.

PubMed

Huryn, Donna M; Brodsky, Jeffrey L; Brummond, Kay M; Chambers, Peter G; Eyer, Benjamin; Ireland, Alex W; Kawasumi, Masaoki; Laporte, Matthew G; Lloyd, Kayla; Manteau, Baptiste; Nghiem, Paul; Quade, Bettina; Seguin, Sandlin P; Wipf, Peter

2011-04-26

Unique chemical methodology enables the synthesis of innovative and diverse scaffolds and chemotypes and allows access to previously unexplored "chemical space." Compound collections based on such new synthetic methods can provide small-molecule probes of proteins and/or pathways whose functions are not fully understood. We describe the identification, characterization, and evolution of two such probes. In one example, a pathway-based screen for DNA damage checkpoint inhibitors identified a compound, MARPIN (ATM and ATR pathway inhibitor) that sensitizes p53-deficient cells to DNA-damaging agents. Modification of the small molecule and generation of an immobilized probe were used to selectively bind putative protein target(s) responsible for the observed activity. The second example describes a focused library approach that relied on tandem multicomponent reaction methodologies to afford a series of modulators of the heat shock protein 70 (Hsp70) molecular chaperone. The synthesis of libraries based on the structure of MAL3-101 generated a collection of chemotypes, each modulating Hsp70 function, but exhibiting divergent pharmacological activities. For example, probes that compromise the replication of a disease-associated polyomavirus were identified. These projects highlight the importance of chemical methodology development as a source of small-molecule probes and as a drug discovery starting point.

Chemical methodology as a source of small-molecule checkpoint inhibitors and heat shock protein 70 (Hsp70) modulators

PubMed Central

Huryn, Donna M.; Brodsky, Jeffrey L.; Brummond, Kay M.; Chambers, Peter G.; Eyer, Benjamin; Ireland, Alex W.; Kawasumi, Masaoki; LaPorte, Matthew G.; Lloyd, Kayla; Manteau, Baptiste; Nghiem, Paul; Quade, Bettina; Seguin, Sandlin P.; Wipf, Peter

2011-01-01

Unique chemical methodology enables the synthesis of innovative and diverse scaffolds and chemotypes and allows access to previously unexplored “chemical space.” Compound collections based on such new synthetic methods can provide small-molecule probes of proteins and/or pathways whose functions are not fully understood. We describe the identification, characterization, and evolution of two such probes. In one example, a pathway-based screen for DNA damage checkpoint inhibitors identified a compound, MARPIN (ATM and ATR pathway inhibitor) that sensitizes p53-deficient cells to DNA-damaging agents. Modification of the small molecule and generation of an immobilized probe were used to selectively bind putative protein target(s) responsible for the observed activity. The second example describes a focused library approach that relied on tandem multicomponent reaction methodologies to afford a series of modulators of the heat shock protein 70 (Hsp70) molecular chaperone. The synthesis of libraries based on the structure of MAL3-101 generated a collection of chemotypes, each modulating Hsp70 function, but exhibiting divergent pharmacological activities. For example, probes that compromise the replication of a disease-associated polyomavirus were identified. These projects highlight the importance of chemical methodology development as a source of small-molecule probes and as a drug discovery starting point. PMID:21502524

Variable Conductance Heat Pipe Cooling of Stirling Convertor and General Purpose Heat Source

NASA Technical Reports Server (NTRS)

Tarau, Calin; Schwendeman, Carl; Anderson William G.; Cornell, Peggy A.; Schifer, Nicholas A.

2013-01-01

In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 degC temperature increase from the nominal vapor temperature. The 19 degC temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental results from integrating the VCHP with an operating Stirling convertor and describes the methodology used to achieve their successful combined operation.

Micro-Thermoelectric Generation Modules Fabricated with Low-Cost Mechanical Machining Processes

NASA Astrophysics Data System (ADS)

Liu, Dawei; Jin, A. J.; Peng, Wenbo; Li, Qiming; Gao, Hu; Zhu, Lianjun; Li, Fu; Zhu, Zhixiang

2017-05-01

Micro/small-scale thermoelectric generation modules are able to produce continuous, noise-free and reliable electricity power using low temperature differences that widely exist in nature or industry. These advantages bring them great application prospects in the fields of remote monitoring, microelectronics/micro-electromechanical systems (MEMS), medical apparatus and smart management system, which often require a power source free of maintenance and vibration. In this work, a prototypical thermoelectric module (12 mm × 12 mm × 0.8 mm) with 15 pairs of micro-scale thermoelectric legs (0.2 mm in width and 0.6 mm in height for each leg) is fabricated using a low-cost mechanical machining process. In this process, cutting and polishing are the main methods for the preparation of thermoelectric pairs from commercial polycrystalline materials and for the fabrication of electrode patterns. The as-fabricated module is tested for its power generation properties with the hot side heated by an electrical heater and the cold side by cold air. With the heater temperature of 375 K, the thermoelectric potential is about 9.1 mV, the short circuit current is about 14.5 mA, and the maximum output power is about 32.8 μW. The finite element method is applied to analyze the heat transfer of the module during our test. The temperature difference and heat flux are simulated, according to which the output powers at different temperatures are calculated, and the result is relatively consistent compared to the test results.

Synergy between fast-ion transport by core MHD and test blanket module fields in DIII-D experiments

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

Heidbrink, W. W.; Austin, M. E.; Collins, C. S.

2015-07-21

We measured fast-ion transport caused by the combination of MHD and a mock-up test-blanket module (TBM) coil in the DIII-D tokamak. The primary diagnostic is an infrared camera that measures the heat flux on the tiles surrounding the coil. The combined effects of the TBM and four other potential sources of transport are studied: neoclassical tearing modes, Alfvén eigenmodes, sawteeth, and applied resonant magnetic perturbation fields for the control of edge localized modes. A definitive synergistic effect is observed at sawtooth crashes where, in the presence of the TBM, the localized heat flux at a burst increases from 0.36 ±0.27more » to 2.6 ±0.5 MW/m -2.« less

Specification for strontium-90 500-watt(e) radioisotopic thermoelectric generator

NASA Astrophysics Data System (ADS)

Hammel, T.; Himes, J.; Lieberman, A.; McGrew, J. W.; Owings, D.; Schumann, F.

1983-04-01

A conceptual design for a demonstration 500-watt(e) radioisotopic thermoelectric generator (RTG) was created. The design effort was divided into two tasks, viz., create a design specification for a capsule strenth member that utilizes a standard Strontium 90 fluoride filled WESF inner liner, and create a conceptual design for a 500-watt(e) RTG. The strength member specification was designed to survive an external pressure of 24,500 psi and meet the requirements of special form radioisotope heat sources. Therefore the capsule is if desired, licensed for domestic and international transport. The design for the RTG features a radioisotopic heat source, an array of nine capsules in a tungsten biological shield, four current technology series connected thermoelectric conversion modules, low conductivity thermal insulation, and a passive finned housing radiator for waste heat dissipation. The preliminary RTG specification formulated previous to contract award was met or exceeded.

Design, fabrication, and testing of energy-harvesting thermoelectric generator

NASA Astrophysics Data System (ADS)

Jovanovic, Velimir; Ghamaty, Saeid

2006-03-01

An energy-harvesting thermoelectric generator (TEG) is being developed to provide power for wireless sensors used in health monitoring of Navy machinery. TEGs are solid-state devices that convert heat directly into electricity without any moving parts. In this application, the TEGs utilize the heat transfer between shipboard waste heat sources and the ambient air to generate electricity. In order to satisfy the required small design volume of less than one cubic inch, Hi-Z is using its innovative thin-film Quantum Well (QW) thermoelectric technology that will provide a factor of four increase in efficiency and a large reduction in the device volume over the currently used bulk Bi IITe 3 based thermoelectics. QWs are nanostructured multi-layer films. These wireless sensors can be used to detect cracks, corrosion, impact damage, and temperature and vibration excursions as part of the Condition Based Maintenance (CBM) of the Navy ship machinery. The CBM of the ship machinery can be significantly improved by automating the process with the use of self-powered wireless sensors. These power-harvesting TEGs can be used to replace batteries as electrical power sources and to eliminate power cables and data lines. The first QW TEG module was fabricated and initial tests were successful. It is planned to conduct performance tests the entire prototype QW TEG device (consisting of the TEG module, housing, thermal insulation and the heat sink) in a simulated thermal environment of a Navy ship.

Wireless power using magnetic resonance coupling for neural sensing applications

NASA Astrophysics Data System (ADS)

Yoon, Hargsoon; Kim, Hyunjung; Choi, Sang H.; Sanford, Larry D.; Geddis, Demetris; Lee, Kunik; Kim, Jaehwan; Song, Kyo D.

2012-04-01

Various wireless power transfer systems based on electromagnetic coupling have been investigated and applied in many biomedical applications including functional electrical stimulation systems and physiological sensing in humans and animals. By integrating wireless power transfer modules with wireless communication devices, electronic systems can deliver data and control system operation in untethered freely-moving conditions without requiring access through the skin, a potential source of infection. In this presentation, we will discuss a wireless power transfer module using magnetic resonance coupling that is specifically designed for neural sensing systems and in-vivo animal models. This research presents simple experimental set-ups and circuit models of magnetic resonance coupling modules and discusses advantages and concerns involved in positioning and sizing of source and receiver coils compared to conventional inductive coupling devices. Furthermore, the potential concern of tissue heating in the brain during operation of the wireless power transfer systems will also be addressed.

Concentrator hot-spot testing, phase 1

NASA Technical Reports Server (NTRS)

Gonzalez, C. C.

1987-01-01

Results of a study to determine the hot-spot susceptibility of concentrator cells, to provide a hot-spot qualification test for concentrator modules, and to provide guidelines for reducing hot-spot susceptibility are presented. Hot-spot heating occurs in a photovoltaic module when the short-circuit current of a cell is lower than the string operating current forcing the cell into reverse bias with a concurrent power dissipation. Although the basis for the concentrator module hot-spot qualification test is the test developed for flat-plate modules, issues, such as providing cell illumination, introduce additional complexities into the testing procedure. The same general guidelines apply for protecting concentrator modules from hot-spot stressing as apply to flat-plate modules. Therefore, recommendations are made on the number of bypass diodes required per given number of series cells per module or source circuit. In addition, a new method for determining the cell temperature in the laboratory or in the field is discussed.

Heat-Pipe-Associated Localized Thermoelectric Power Generation System

NASA Astrophysics Data System (ADS)

Kim, Pan-Jo; Rhi, Seok-Ho; Lee, Kye-Bock; Hwang, Hyun-Chang; Lee, Ji-Su; Jang, Ju-Chan; Lee, Wook-Hyun; Lee, Ki-Woo

2014-06-01

The present study focused on how to improve the maximum power output of a thermoelectric generator (TEG) system and move heat to any suitable space using a TEG associated with a loop thermosyphon (loop-type heat pipe). An experimental study was carried out to investigate the power output, the temperature difference of the thermoelectric module (TEM), and the heat transfer performance associated with the characteristic of the researched heat pipe. Currently, internal combustion engines lose more than 35% of their fuel energy as recyclable heat in the exhaust gas, but it is not easy to recycle waste heat using TEGs because of the limited space in vehicles. There are various advantages to use of TEGs over other power sources, such as the absence of moving parts, a long lifetime, and a compact system configuration. The present study presents a novel TEG concept to transfer heat from the heat source to the sink. This technology can transfer waste heat to any location. This simple and novel design for a TEG can be applied to future hybrid cars. The present TEG system with a heat pipe can transfer heat and generate power of around 1.8 V with T TEM = 58°C. The heat transfer performance of a loop-type heat pipe with various working fluids was investigated, with water at high heat flux (90 W) and 0.05% TiO2 nanofluid at low heat flux (30 W to 70 W) showing the best performance in terms of power generation. The heat pipe can transfer the heat to any location where the TEM is installed.

Numerical study of mixed convection heat transfer enhancement in a channel with active flow modulation

NASA Astrophysics Data System (ADS)

Billah, Md. Mamun; Khan, Md Imran; Rahman, Mohammed Mizanur; Alam, Muntasir; Saha, Sumon; Hasan, Mohammad Nasim

2017-06-01

A numerical study of steady two dimensional mixed convention heat transfer phenomena in a rectangular channel with active flow modulation is carried out in this investigation. The flow in the channel is modulated via a rotating cylinder placed at the center of the channel. In this study the top wall of the channel is subjected to an isothermal low temperature while a discrete isoflux heater is positioned on the lower wall. The fluid flow under investigation is assumed to have a Prandtl number of 0.71 while the Reynolds No. and the Grashof No. are varied in wide range for four different situations such as: i) plain channel with no cylinder, ii) channel with stationary cylinder, iii) channel with clockwise rotating cylinder and iv) channel with counter clockwise rotating cylinder. The results obtained in this study are presented in terms of the distribution of streamlines, isotherms in the channel while the heat transfer process from the heat source is evaluated in terms of the local Nusselt number, average Nusselt number. The outcomes of this study also indicate that the results are strongly dependent on the type of configuration and direction of rotation of the cylinder and that the average Nusselt number value rises with an increase in Reynolds and Grashof numbers but the correlation between these parameters at higher values of Reynolds and Grashof numbers becomes weak.

Conceptual Trade Study of General Purpose Heat Source Powered Stirling Converter Configurations

NASA Technical Reports Server (NTRS)

Turpin, J. B.

2007-01-01

This Technical Manual describes a parametric study of general purpose heat source (GPHS) powered Stirling converter configurations. This study was performed in support of MSFC s efforts to establish the capability to perform non-nuclear system level testing and integration of radioisotope power systems. Six different GPHS stack configurations at a total of three different power levels (80, 250, and 500 W(sub e) were analyzed. The thermal profiles of the integrated GPHS modules (for each configuration) were calculated to determine maximum temperatures for comparison to allowable material limits. Temperature profiles for off-nominal power conditions were also assessed in order to better understand how power demands from the Stirling engine impact the performance of a given configuration.

Indoor unit for electric heat pump

DOEpatents

Draper, R.; Lackey, R.S.; Fagan, T.J. Jr.; Veyo, S.E.; Humphrey, J.R.

1984-05-22

An indoor unit for an electric heat pump is provided in modular form including a refrigeration module, an air mover module, and a resistance heat package module, the refrigeration module including all of the indoor refrigerant circuit components including the compressor in a space adjacent the heat exchanger, the modules being adapted to be connected to air flow communication in several different ways as shown to accommodate placement of the unit in various orientations. 9 figs.

Modeling the photoacoustic signal during the porous silicon formation

NASA Astrophysics Data System (ADS)

Ramirez-Gutierrez, C. F.; Castaño-Yepes, J. D.; Rodriguez-García, M. E.

2017-01-01

Within this work, the kinetics of the growing stage of porous silicon (PS) during the etching process was studied using the photoacoustic technique. A p-type Si with low resistivity was used as a substrate. An extension of the Rosencwaig and Gersho model is proposed in order to analyze the temporary changes that take place in the amplitude of the photoacoustic signal during the PS growth. The solution of the heat equation takes into account the modulated laser beam, the changes in the reflectance of the PS-backing heterostructure, the electrochemical reaction, and the Joule effect as thermal sources. The model includes the time-dependence of the sample thickness during the electrochemical etching of PS. The changes in the reflectance are identified as the laser reflections in the internal layers of the system. The reflectance is modeled by an additional sinusoidal-monochromatic light source and its modulated frequency is related to the velocity of the PS growth. The chemical reaction and the DC components of the heat sources are taken as an average value from the experimental data. The theoretical results are in agreement with the experimental data and hence provided a method to determine variables of the PS growth, such as the etching velocity and the thickness of the porous layer during the growing process.

Electrical performance analysis and economic evaluation of combined biomass cook stove thermoelectric (BITE) generator.

PubMed

Lertsatitthanakorn, C

2007-05-01

The use of biomass cook stoves is widespread in the domestic sector of developing countries, but the stoves are not efficient. To advance the versatility of the cook stove, we investigated the feasibility of adding a commercial thermoelectric (TE) module made of bismuth-telluride based materials to the stove's side wall, thereby creating a thermoelectric generator system that utilizes a proportion of the stove's waste heat. The system, a biomass cook stove thermoelectric generator (BITE), consists of a commercial TE module (Taihuaxing model TEP1-1264-3.4), a metal sheet wall which acts as one side of the stove's structure and serves as the hot side of the TE module, and a rectangular fin heat sink at the cold side of the TE module. An experimental set-up was built to evaluate the conversion efficiency at various temperature ranges. The experimental set-up revealed that the electrical power output and the conversion efficiency depended on the temperature difference between the cold and hot sides of the TE module. At a temperature difference of approximately 150 degrees C, the unit achieved a power output of 2.4W. The conversion efficiency of 3.2% was enough to drive a low power incandescent light bulb or a small portable radio. A theoretical model approximated the power output at low temperature ranges. An economic analysis indicated that the payback period tends to be very short when compared with the cost of the same power supplied by batteries. Therefore, the generator design formulated here could be used in the domestic sector. The system is not intended to compete with primary power sources but serves adequately as an emergency or backup source of power.

Non-linear lumped model circuit of capacitively coupled plasmas at the intermediate radio-frequencies

NASA Astrophysics Data System (ADS)

Shihab, Mohammed

2018-06-01

The discharge dynamics in geometrically asymmetric capacitively coupled plasmas are investigated via a lumped model circuit. A realistic reactor configuration is assumed. A single and two separate RF voltage sources are considered. One of the driven frequencies (the higher frequency) has been adjusted to excite a plasma series resonance, while the second frequency (the lower frequency) is in the range of the ion plasma frequency. Increasing the plasma pressure in the low pressure regime (≤ 100mTorr) is found to diminish the amplitude of the self-excited harmonics of the discharge current, however, the net result is enhancing the plasma heating. The modulation of the ion density with the lower driving frequency affect the plasma heating considerably. The net effect depends on the amplitude and the phase of the ion modulation.

Optical Sensor of Thermal Gas Flow Based on Fiber Bragg Grating.

PubMed

Jiang, Xu; Wang, Keda; Li, Junqing; Zhan, Hui; Song, Zhenan; Che, Guohang; Lyu, Guohui

2017-02-15

This paper aims at solving the problem of explosion proof in measurement of thermal gas flow using electronic sensor by presenting a new type of flow sensor by optical fiber heating. A measuring unit based on fiber Bragg grating (FBG) for fluid temperature and a unit for heat dissipation are designed to replace the traditional electronic sensors. The light in C band from the amplified spontaneous emission (ASE) light source is split, with one part used to heat the absorbing coating and the other part used in the signal processing unit. In the heating unit, an absorbing coating is introduced to replace the traditional resistance heating module to minimize the risk of explosion. The measurement results demonstrate a fine consistency between the flow and temperature difference in simulation. The method to enhance the measurement resolution of flow is also discussed.

Numerical modeling of the thermoelectric cooler with a complementary equation for heat circulation in air gaps

NASA Astrophysics Data System (ADS)

Fang, En; Wu, Xiaojie; Yu, Yuesen; Xiu, Junrui

2017-03-01

In this paper, a numerical model is developed by combining thermodynamics with heat transfer theory. Taking inner and external multi-irreversibility into account, it is with a complementary equation for heat circulation in air gaps of a steady cooling system with commercial thermoelectric modules operating in refrigeration mode. With two modes concerned, the equation presents the heat flowing through air gaps which forms heat circulations between both sides of thermoelectric coolers (TECs). In numerical modelling, a TEC is separated as two temperature controlled constant heat flux reservoirs in a thermal resistance network. In order to obtain the parameter values, an experimental apparatus with a commercial thermoelectric cooler was built to characterize the performance of a TEC with heat source and sink assembly. At constant power dissipation, steady temperatures of heat source and both sides of the thermoelectric cooler were compared with those in a standard numerical model. The method displayed that the relationship between Φf and the ratio Φ_{c}'/Φ_{c} was linear as expected. Then, for verifying the accuracy of proposed numerical model, the data in another system were recorded. It is evident that the experimental results are in good agreement with simulation(proposed model) data at different heat transfer rates. The error is small and mainly results from the instabilities of thermal resistances with temperature change and heat flux, heat loss of the device vertical surfaces and measurements.

Indoor unit for electric heat pump

DOEpatents

Draper, Robert; Lackey, Robert S.; Fagan, Jr., Thomas J.; Veyo, Stephen E.; Humphrey, Joseph R.

1984-01-01

An indoor unit for an electric heat pump is provided in modular form including a refrigeration module 10, an air mover module 12, and a resistance heat package module 14, the refrigeration module including all of the indoor refrigerant circuit components including the compressor 36 in a space adjacent the heat exchanger 28, the modules being adapted to be connected to air flow communication in several different ways as shown in FIGS. 4-7 to accommodate placement of the unit in various orientations.

Plasma Heating and Ultrafast Semiconductor Laser Modulation Through a Terahertz Heating Field

NASA Technical Reports Server (NTRS)

Li, Jian-Zhong; Ning, C. Z.

2000-01-01

Electron-hole plasma heating and ultrafast modulation in a semiconductor laser under a terahertz electrical field are investigated using a set of hydrodynamic equations derived from the semiconductor Bloch equations. The self-consistent treatment of lasing and heating processes leads to the prediction of a strong saturation and degradation of modulation depth even at moderate terahertz field intensity. This saturation places a severe limit to bandwidth achievable with such scheme in ultrafast modulation. Strategies for increasing modulation depth are discussed.

Water and Health. What We Take from our Environment. Science and Technology Education in Philippine Society.

ERIC Educational Resources Information Center

Philippines Univ., Quezon City. Inst. for Science and Mathematics Education Development.

Information about the relationship between water and health is provided in this module. Topics considered include: (1) the various uses of water; (2) water demand of individuals in certain communities; (3) water sources; (4) water cycle; (5) pure water; (6) water pollution, focusing on pollution resulting from heat, chemicals, radioactive…

Hot-spot qualification testing of concentrator modules

NASA Technical Reports Server (NTRS)

Gonzalez, C. C.; Sugimura, R. S.; Ross, R. G., Jr.

1987-01-01

Results of a study to determine the hot-spot susceptibility of concentrator cells, to provide a hot-spot qualification test for concentrator modules, and to provide guidelines for reducing hot-spot susceptibility are presented. Hot-spot heating occurs in a photovoltaic module when the short-circuit current of a cell is lower than the string operating current, forcing the cell into reverse bias with a concurrent power dissipation. Although the basis for the concentrator-module hot-spot qualification test is the test developed for flat-plate modules, issues such as providing cell illumination introduce additional complexities into the testing procedure. The results indicate that the same general guidelines apply to protecting concentrator modules from hot-spot stressing as apply to flat-plate modules, and recommendations are made on the number of bypass diodes required per given number of series cells per module or source circuit. A method for determining the cell temperature in the laboratory or in the field is discussed.

Lattice Boltzmann simulations of heat transfer in fully developed periodic incompressible flows

NASA Astrophysics Data System (ADS)

Wang, Zimeng; Shang, Helen; Zhang, Junfeng

2017-06-01

Flow and heat transfer in periodic structures are of great interest for many applications. In this paper, we carefully examine the periodic features of fully developed periodic incompressible thermal flows, and incorporate them in the lattice Boltzmann method (LBM) for flow and heat transfer simulations. Two numerical approaches, the distribution modification (DM) approach and the source term (ST) approach, are proposed; and they can both be used for periodic thermal flows with constant wall temperature (CWT) and surface heat flux boundary conditions. However, the DM approach might be more efficient, especially for CWT systems since the ST approach requires calculations of the streamwise temperature gradient at all lattice nodes. Several example simulations are conducted, including flows through flat and wavy channels and flows through a square array with circular cylinders. Results are compared to analytical solutions, previous studies, and our own LBM calculations using different simulation techniques (i.e., the one-module simulation vs. the two-module simulation, and the DM approach vs. the ST approach) with good agreement. These simple, however, representative simulations demonstrate the accuracy and usefulness of our proposed LBM methods for future thermal periodic flow simulations.

Evaluation of fiber reinforced polymers using active infrared thermography system with thermoelectric cooling modules

NASA Astrophysics Data System (ADS)

Chady, Tomasz; Gorący, Krzysztof

2018-04-01

Active infrared thermography is increasingly used for nondestructive testing of various materials. Properties of this method are creating a unique possibility to utilize it for inspection of composites. In the case of active thermography, an external energy source is usually used to induce a thermal contrast inside tested objects. The conventional heating methods (like halogen lamps or flash lamps) are utilized for this purpose. In this study, we propose to use a cooling unit. The proposed system consists of a thermal imaging infrared camera, which is used to observe the surface of the inspected specimen and a specially designed cooling unit with thermoelectric modules (the Peltier modules).

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 (below -15 W) heat loads, respectively, in all treatments. For heat loads between -15 W and 20 W, the increase in heart rate was smaller for the 'unnatural' heating by convection in water compared with either treatment using radiant heating. Our data indicate that changes in heart rate constitute a thermoregulatory mechanism that is modulated in response to the thermal environment occupied by the animal, but that heart rate during heating and cooling is, in part, controlled independently of body temperature.

From Modules to a Generator: An Integrated Heat Exchanger Concept for Car Applications of a Thermoelectric Generator

NASA Astrophysics Data System (ADS)

Bosch, Henry

2016-03-01

A heat exchanger concept for a thermoelectric generator with integrated planar modules for passenger car applications is introduced. The module housings, made of deep drawn stainless steel sheet metal, are brazed onto the exhaust gas channel to achieve an optimal heat transfer on the hot side of the modules. The cooling side consists of winding fluid channels, which are mounted directly onto the cold side of the modules. Only a thin foil separates the cooling media from the modules for an almost direct heat contact on the cooling side. Thermoelectric generators with up to 20 modules made of PbTe and Bi2Te3, respectively, are manufactured and tested on a hot gas generator to investigate electrical power output and performance of the thermoelectric generator. The proof of concept of the light weight heat exchanger design made of sheet metal with integrated modules is positively accomplished.

Electronic modules easily separated from heat sink

NASA Technical Reports Server (NTRS)

1965-01-01

Metal heat sink and electronic modules bonded to a thermal bridge can be easily cleaved for removal of the modules for replacement or repair. A thin film of grease between a fluorocarbon polymer film on the metal heat sink and an adhesive film on the modules acts as the cleavage plane.

Exciting Alfven Waves using Modulated Electron Heating by High Power Microwaves

NASA Astrophysics Data System (ADS)

Wang, Yuhou; Gekelman, Walter; Pribyl, Patrick; van Compernolle, Bart; Papadopoulos, Konstantinos

2014-10-01

Experiments exploring the physics of ionospheric modification with intense perpendicular propagating waves (k-> ⊥B->0) on the Large Plasma Device (LaPD) at UCLA have been upgraded with the addition of a high power rapidly pulsed microwave source. The plasma is irradiated with ten pulses (250 kW X-band) near the upper-hybrid frequency. The pulses are modulated at a frequency of a fraction (0.1-1.0) of fci (ion cyclotron frequency). Based on a previous single-pulse experiment, the modulated electron heating may drive a large amplitude shear Alfvén wave (f

Study of light-absorbing crystal birefringence and electrical modulation mechanisms for coupled thermal-optical effects.

PubMed

Zhou, Ji; He, Zhihong; Ma, Yu; Dong, Shikui

2014-09-20

This paper discusses Gaussian laser transmission in double-refraction crystal whose incident light wavelength is within its absorption wave band. Two scenarios for coupled radiation and heat conduction are considered: one is provided with an applied external electric field, the other is not. A circular heat source with a Gaussian energy distribution is introduced to present the crystal's light-absorption process. The electromagnetic field frequency domain analysis equation and energy equation are solved to simulate the phenomenon by using the finite element method. It focuses on the influence of different values such as wavelength, incident light intensity, heat transfer coefficient, ambient temperature, crystal thickness, and applied electric field strength. The results show that the refraction index of polarized light increases with the increase of crystal temperature. It decreases as the strength of the applied electric field increases if it is positive. The mechanism of electrical modulation for the thermo-optical effect is used to keep the polarized light's index of refraction constant in our simulation. The quantitative relation between thermal boundary condition and strength of applied electric field during electrical modulation is determined. Numerical results indicate a possible approach to removing adverse thermal effects such as depolarization and wavefront distortion, which are caused by thermal deposition during linear laser absorption.

High-Performance Silicon-Germanium-Based Thermoelectric Modules for Gas Exhaust Energy Scavenging

NASA Astrophysics Data System (ADS)

Romanjek, K.; Vesin, S.; Aixala, L.; Baffie, T.; Bernard-Granger, G.; Dufourcq, J.

2015-06-01

Some of the energy used in transportation and industry is lost as heat, often at high-temperatures, during conversion processes. Thermoelectricity enables direct conversion of heat into electricity, and is an alternative to the waste-heat-recovery technology currently used, for example turbines and other types of thermodynamic cycling. The performance of thermoelectric (TE) materials and modules has improved continuously in recent decades. In the high-temperature range ( T hot side > 500°C), silicon-germanium (SiGe) alloys are among the best TE materials reported in the literature. These materials are based on non-toxic elements. The Thermoelectrics Laboratory at CEA (Commissariat à l'Energie Atomique et aux Energies Alternatives) has synthesized n and p-type SiGe pellets, manufactured TE modules, and integrated these into thermoelectric generators (TEG) which were tested on a dedicated bench with hot air as the source of heat. SiGe TE samples of diameter 60 mm were created by spark-plasma sintering. For n-type SiGe doped with phosphorus the peak thermoelectric figure of merit reached ZT = 1.0 at 700°C whereas for p-type SiGe doped with boron the peak was ZT = 0.75 at 700°C. Thus, state-of-the-art conversion efficiency was obtained while also achieving higher production throughput capacity than for competing processes. A standard deviation <4% in the electrical resistance of batches of ten pellets of both types was indicative of high reproducibility. A silver-paste-based brazing technique was used to assemble the TE elements into modules. This assembly technique afforded low and repeatable electrical contact resistance (<3 nΩ m2). A test bench was developed for measuring the performance of TE modules at high temperatures (up to 600°C), and thirty 20 mm × 20 mm TE modules were produced and tested. The results revealed the performance was reproducible, with power output reaching 1.9 ± 0.2 W for a 370 degree temperature difference. When the temperature difference was increased to 500°C, electrical power output increased to >3.6 W. An air-water heat exchanger was developed and 30 TE modules were clamped and connected electrically. The TEG was tested under vacuum on a hot-air test bench. The measured output power was 45 W for an air flow of 16 g/s at 750°C. The hot surface of the TE module reached 550°C under these conditions. Silicon-germanium TE modules can survive such temperatures, in contrast with commercial modules based on bismuth telluride, which are limited to 400°C.

Motorcycle waste heat energy harvesting

NASA Astrophysics Data System (ADS)

Schlichting, Alexander D.; Anton, Steven R.; Inman, Daniel J.

2008-03-01

Environmental concerns coupled with the depletion of fuel sources has led to research on ethanol, fuel cells, and even generating electricity from vibrations. Much of the research in these areas is stalling due to expensive or environmentally contaminating processes, however recent breakthroughs in materials and production has created a surge in research on waste heat energy harvesting devices. The thermoelectric generators (TEGs) used in waste heat energy harvesting are governed by the Thermoelectric, or Seebeck, effect, generating electricity from a temperature gradient. Some research to date has featured platforms such as heavy duty diesel trucks, model airplanes, and automobiles, attempting to either eliminate heavy batteries or the alternator. A motorcycle is another platform that possesses some very promising characteristics for waste heat energy harvesting, mainly because the exhaust pipes are exposed to significant amounts of air flow. A 1995 Kawasaki Ninja 250R was used for these trials. The module used in these experiments, the Melcor HT3-12-30, produced an average of 0.4694 W from an average temperature gradient of 48.73 °C. The mathematical model created from the Thermoelectric effect equation and the mean Seebeck coefficient displayed by the module produced an average error from the experimental data of 1.75%. Although the module proved insufficient to practically eliminate the alternator on a standard motorcycle, the temperature data gathered as well as the examination of a simple, yet accurate, model represent significant steps in the process of creating a TEG capable of doing so.

Applications of thermoelectric modules on heat flow detection.

PubMed

Leephakpreeda, Thananchai

2012-03-01

This paper presents quantitative analysis and practical scenarios of implementation of the thermoelectric module for heat flow detection. Mathematical models of the thermoelectric effects are derived to describe the heat flow from/to the detected media. It is observed that the amount of the heat flow through the thermoelectric module proportionally induces the conduction heat owing to the temperature difference between the hot side and the cold side of the thermoelectric module. In turn, the Seebeck effect takes place in the thermoelectric module where the temperature difference is converted to the electric voltage. Hence, the heat flow from/to the detected media can be observed from both the amount and the polarity of the voltage across the thermoelectric module. Two experiments are demonstrated for viability of the proposed technique by the measurements of the heat flux through the building wall and thermal radiation from the outdoor environment during daytime. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Heating Structures Derived from Satellite

NASA Technical Reports Server (NTRS)

Tao, W.-K.; Adler, R.; Haddad, Z.; Hou, A.; Kakar, R.; Krishnamurti, T. N.; Kummerow, C.; Lang, S.; Meneghini, R.; Olson, W.

2004-01-01

Rainfall is a key link in the hydrologic cycle and is a primary heat source for the atmosphere. The vertical distribution of latent-heat release, which is accompanied by rainfall, modulates the large-scale circulations of the tropics and in turn can impact midlatitude weather. This latent heat release is a consequence of phase changes between vapor, liquid, and solid water. The Tropical Rainfall Measuring Mission (TRMM), a joint U.S./Japan space project, was launched in November 1997. It provides an accurate measurement of rainfall over the global tropics which can be used to estimate the four-dimensional structure of latent heating over the global tropics. The distributions of rainfall and inferred heating can be used to advance our understanding of the global energy and water cycle. This paper describes several different algorithms for estimating latent heating using TRMM observations. The strengths and weaknesses of each algorithm as well as the heating products are also discussed. The validation of heating products will be exhibited. Finally, the application of this heating information to global circulation and climate models is presented.

Anomalous electron heating effects on the E region ionosphere in TIEGCM

NASA Astrophysics Data System (ADS)

Liu, Jing; Wang, Wenbin; Oppenheim, Meers; Dimant, Yakov; Wiltberger, Michael; Merkin, Slava

2016-03-01

We have recently implemented a new module that includes both the anomalous electron heating and the electron-neutral cooling rate correction associated with the Farley-Buneman Instability (FBI) in the thermosphere-ionosphere electrodynamics global circulation model (TIEGCM). This implementation provides, for the first time, a modeling capability to describe macroscopic effects of the FBI on the ionosphere and thermosphere in the context of a first-principle, self-consistent model. The added heating sources primarily operate between 100 and 130 km altitude, and their magnitudes often exceed auroral precipitation heating in the TIEGCM. The induced changes in E region electron temperature in the auroral oval and polar cap by the FBI are remarkable with a maximum Te approaching 2200 K. This is about 4 times larger than the TIEGCM run without FBI heating. This investigation demonstrates how researchers can add the important effects of the FBI to magnetosphere-ionosphere-thermosphere models and simulators.

Use of .sup.3 He.sup.30 + ICRF minority heating to simulate alpha particle heating

DOEpatents

Post, Jr., Douglass E.; Hwang, David Q.; Hovey, Jane

1986-04-22

Neutron activation due to high levels of neutron production in a first heated deuterium-tritium plasma is substantially reduced by using Ion Cyclotron Resonance Frequency (ICRF) heating of energetic .sup.3 He.sup.++ ions in a second deuterium-.sup.3 He.sup.++ plasma which exhibit an energy distribution and density similar to that of alpha particles in fusion reactor experiments to simulate fusion alpha particle heating in the first plasma. The majority of the fast .sup.3 He.sup.++ ions and their slowing down spectrum can be studied using either a modulated hydrogen beam source for producing excited states of He.sup.+ in combination with spectrometers or double charge exchange with a high energy neutral lithium beam and charged particle detectors at the plasma edge. The maintenance problems thus associated with neutron activation are substantially reduced permitting energetic alpha particle behavior to be studied in near term large fusion experiments.

Harmattan, Saharan heat low, and West African monsoon circulation: modulations on the Saharan dust outflow towards the North Atlantic

NASA Astrophysics Data System (ADS)

Schepanski, Kerstin; Heinold, Bernd; Tegen, Ina

2017-09-01

The outflow of dust from the northern African continent towards the North Atlantic is stimulated by the atmospheric circulation over North Africa, which modulates the spatio-temporal distribution of dust source activation and consequently the entrainment of mineral dust into the boundary layer, as well as the transport of dust out of the source regions. The atmospheric circulation over the North African dust source regions, predominantly the Sahara and the Sahel, is characterized by three major circulation regimes: (1) the harmattan (trade winds), (2) the Saharan heat low (SHL), and (3) the West African monsoon circulation. The strength of the individual regimes controls the Saharan dust outflow by affecting the spatio-temporal distribution of dust emission, transport pathways, and deposition fluxes.This study aims at investigating the atmospheric circulation pattern over North Africa with regard to its role favouring dust emission and dust export towards the tropical North Atlantic. The focus of the study is on summer 2013 (June to August), during which the SALTRACE (Saharan Aerosol Long-range TRansport and Aerosol-Cloud interaction Experiment) field campaign also took place. It involves satellite observations by the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) flying on board the geostationary Meteosat Second Generation (MSG) satellite, which are analysed and used to infer a data set of active dust sources. The spatio-temporal distribution of dust source activation frequencies (DSAFs) allows for linking the diurnal cycle of dust source activations to dominant meteorological controls on dust emission. In summer, Saharan dust source activations clearly differ from dust source activations over the Sahel regarding the time of day when dust emission begins. The Sahara is dominated by morning dust source activations predominantly driven by the breakdown of the nocturnal low-level jet. In contrast, dust source activations in the Sahel are predominantly activated during the second half of the day, when downdrafts associated with deep moist convection are the major atmospheric driver. Complementary to the satellite-based analysis on dust source activations and implications from their diurnal cycle, simulations on atmosphere and dust life cycle were performed using the mesoscale atmosphere-dust model system COSMO-MUSCAT (COSMO: COnsortium for Small-scale MOdelling; MUSCAT: MUltiScale Chemistry Aerosol Transport Model). Fields from this simulation were analysed regarding the variability of the harmattan, the Saharan heat low, and the monsoon circulation as well as their impact on the variability of the Saharan dust outflow towards the North Atlantic. This study illustrates the complexity of the interaction among the three major circulation regimes and their modulation of the North African dust outflow. Enhanced westward dust fluxes frequently appear following a phase characterized by a deep SHL. Ultimately, findings from this study contribute to the quantification of the interannual variability of the atmospheric dust burden.

Solar dynamic power module design

NASA Technical Reports Server (NTRS)

Secunde, Richard R.; Labus, Thomas L.; Lovely, Ronald G.

1989-01-01

Studies have shown that use of solar dynamic (SD) power for the growth eras of the Space Station Freedom program will result in life cycle cost savings when compared to power supplied by photovoltaic sources. In the SD power module, a concentrator collects and focuses solar energy into a heat receiver which has integral thermal energy storage. A power conversion unit (PCU) based on the closed Brayton thermodynamic cycle removes thermal energy from the receiver and converts that energy to electrical energy. Since the closed Brayton cycle is a single phase gas cycle, the conversion hardware (heat exchangers, turbine, compressor, etc.) can be designed for operation in low earth orbit, and tested with confidence in test facilities on earth before launch into space. The concentrator subassemblies will be aligned and the receiver/PCU/radiator combination completely assembled and charged with gas and cooling liquid on earth before launch to, and assembly on orbit.

Parametric System Model for a Stirling Radioisotope Generator

NASA Technical Reports Server (NTRS)

Schmitz, Paul C.

2015-01-01

A Parametric System Model (PSM) was created in order to explore conceptual designs, the impact of component changes and power level on the performance of the Stirling Radioisotope Generator (SRG). Using the General Purpose Heat Source (GPHS approximately 250 Wth) modules as the thermal building block from which a SRG is conceptualized, trade studies are performed to understand the importance of individual component scaling on isotope usage. Mathematical relationships based on heat and power throughput, temperature, mass, and volume were developed for each of the required subsystems. The PSM uses these relationships to perform component- and system-level trades.

Parametric System Model for a Stirling Radioisotope Generator

NASA Technical Reports Server (NTRS)

Schmitz, Paul C.

2014-01-01

A Parametric System Model (PSM) was created in order to explore conceptual designs, the impact of component changes and power level on the performance of Stirling Radioisotope Generator (SRG). Using the General Purpose Heat Source (GPHS approximately 250 watt thermal) modules as the thermal building block around which a SRG is conceptualized, trade studies are performed to understand the importance of individual component scaling on isotope usage. Mathematical relationships based on heat and power throughput, temperature, mass and volume were developed for each of the required subsystems. The PSM uses these relationships to perform component and system level trades.

Recommended design and fabrication sequence of AMTEC test assembly

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

Schock, A.; Kumar, V.; Noravian, H.

1998-01-01

A series of previous OSC papers described: 1) a novel methodology for the coupled thermal, fluid flow, and electrical analysis of multitube AMTEC (Alkali Metal Thermal-to-Electric Conversion) cells; 2) the application of that methodology to determine the effect of numerous design variations on the cell{close_quote}s performance, leading to selection and performance characterization of an OSC-recommended cell design; and 3) the design, analysis, and characterization of an OSC-generated power system design combining sixteen of the above AMTEC cells with two or three GPHS (General Purpose Heat Source) radioisotope heat source modules, and the applicability of those power systems to future spacemore » missions ({ital e.g.} Pluto Express and Europa Orbiter) under consideration by NASA. The OSC system design studies demonstrated the critical importance of the thermal insulation subsystem, and culminated in a design in which the eight AMTEC cells on each end of the heat source stack are embedded in Min-K fibrous insulation, and the Min-K and the GPHS modules are surrounded by graded-length Mo multifoil insulation. The present paper depicts the OSC-recommended AMTEC cell and generator designs, and identifies the need for an electrically heated (scaled-down but otherwise prototypic) test assembly for the experimental validation of the generator{close_quote}s system performance predictions. It then describes the design of an OSC-recommended test assembly consisting of an electrical heater enclosed in a graphite box to simulate the radioisotope heat source, four series-connected prototypic AMTEC cells of the OSC-recommended configuration, and a prototypic hybrid insulation package consisting of Min-K and graded-length Mo multifoils. Finally, the paper describes and illustrates an OSC-recommended detailed fabrication sequence and procedure for the above cell and test assembly. That fabrication procedure is being implemented by AMPS, Inc. with the support of DOE{close_quote}s Oak Ridge and Mound Laboratories, and the Air Force Phillips Laboratory (AFPL) will test the performance of the assembly over a range of input thermal powers and output voltages. The experimentally measured performance will be compared with the results of OSC analyses of the same insulated test assembly over the same range of operating parameters. {copyright} {ital 1998 American Institute of Physics.}« less

Solar dynamic power for Space Station Freedom

NASA Technical Reports Server (NTRS)

Labus, Thomas L.; Secunde, Richard R.; Lovely, Ronald G.

1989-01-01

The Space Station Freedom Program is presently planned to consist of two phases. At the completion of Phase 1, Freedom's manned base will consist of a transverse boom with attached manned modules and 75 kW of available electric power supplied by photovoltaic (PV) power sources. In Phase 2, electric power available to the manned base will be increased to 125 kW by the addition of two solar dynamic (SD) power modules, one at each end of the transverse boom. Power for manned base growth beyond Phase 2 will be supplied by additional SD modules. Studies show that SD power for the growth eras will result in life cycle cost savings of $3 to $4 billion when compared to PV-supplied power. In the SD power modules for Space Station Freedom, an offset parabolic concentrator collects and focuses solar energy into a heat receiver. To allow full power operation over the entire orbit, the receiver includes integral thermal energy storage by means of the heat of fusion of a salt mixture. Thermal energy is removed from the receiver and converted to electrical energy by a power conversion unit (PCU) which includes a closed brayton cycle (CBC) heat engine and an alternator. The receiver/PCU/radiator combination will be completely assembled and charged with gas and cooling fluid on earth before launch to orbit. The concentrator subassemblies will be pre-aligned and stowed in the orbiter bay before launch. On orbit, the receiver/PCU/radiator assembly will be installed as a unit. The pre-aligned concentrator panels will then be latched together and the total concentrator attached to the receiver/PCU/radiator by the astronauts. After final electric connections are made and checkout is complete, the SD power module will be ready for operation.

Solar dynamic power for space station freedom

NASA Technical Reports Server (NTRS)

Labus, Thomas L.; Secunde, Richard R.; Lovely, Ronald G.

1989-01-01

The Space Station Freedom Program is presently planned to consist of two phases. At the completion of Phase 1, Freedom's manned base will consist of a transverse boom with attached manned modules and 75 kW of available electric power supplied by photovoltaic (PV) power sources. In Phase 2, electric power available to the manned base will be increased to 125 kW by the addition of two solar dynamic (SD) power modules, one at each end of the transverse boom. Power for manned base growth beyond Phase 2 will be supplied by additional SD modules. Studies show that SD power for the growth eras will result in life cycle cost savings of $3 to $4 billion when compared to PV-supplied power. In the SD power modules for Space Station Freedom, an offset parabolic concentrator collects and focuses solar energy into a heat receiver. To allow full power operation over the entire orbit, the receiver includes integral thermal energy storage by means of the heat of fusion of a salt mixture. Thermal energy is removed from the receiver and converted to electrical energy by a power conversion unit (PCU) which includes a closed brayton cycle (CBC) heat engine and an alternator. The receiver/PCU/radiator combination will be completely assembled and charged with gas and cooling fluid on Earth before launch to orbit. The concentrator subassemblies will be pre-aligned and stowed in the orbiter bay before launch. On orbit, the receiver/PCU/radiator assembly will be installed as a unit. The pre-aligned concentrator panels will then be latched together and the total concentrator attached to the receiver/PCU/radiator by the astronauts. After final electric connections are made and checkout is complete, the SD power module will be ready for operation.

Incorporating Cutting Edge Scientific Results from the Margins-Geoprisms Program into the Undergraduate Curriculum: The Subduction Factory

NASA Astrophysics Data System (ADS)

Penniston-Dorland, S.; Stern, R. J.; Edwards, B. R.; Kincaid, C. R.

2014-12-01

The NSF-MARGINS Program funded a decade of research on continental margin processes. The NSF-GeoPRISMS Mini-lesson Project, funded by NSF-TUES, is designed to integrate fundamental results from the MARGINS program into open-source college-level curriculum. Three Subduction Factory (SubFac) mini-lessons were developed as part of this project. These include hands-on examinations of data sets representing 3 key components of the subduction zone system: 1) Heat transfer in the subducted slab; 2) Metamorphic processes happening at the plate interface; and 3) Typical magmatic products of arc systems above subduction zones. Module 1: "Slab Temperatures Control Melting in Subduction Zones, What Controls Slab Temperature?" allows students to work in groups using beads rolling down slopes as an analog for the mathematics of heat flow. Using this hands-on, exploration-based approach, students develop an intuition for the mathematics of heatflow and learn about heat conduction and advection in the subduction zone environment. Module 2: "Subduction zone metamorphism" introduces students to the metamorphic rocks that form as the subducted slab descends and the mineral reactions that characterize subduction-related metamorphism. This module includes a suite of metamorphic rocks available for instructors to use in a lab, and exercises in which students compare pressure-temperature estimates obtained from metamorphic rocks to predictions from thermal models. Module 3: "Central American Arc Volcanoes, Petrology and Geochemistry" introduces students to basic concepts in igneous petrology using the Central American volcanic arc, a MARGINS Subduction Factory focus site, as an example. The module relates data from two different volcanoes - basaltic Cerro Negro (Nicaragua) and andesitic Ilopango (El Salvador) including hand sample observations and major element geochemistry - to explore processes of mantle and crustal melting and differentiation in arc volcanism.

Modulated heat pulse propagation and partial transport barriers in chaotic magnetic fields

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

Castillo-Negrete, Diego del; Blazevski, Daniel

2016-04-15

Direct numerical simulations of the time dependent parallel heat transport equation modeling heat pulses driven by power modulation in three-dimensional chaotic magnetic fields are presented. The numerical method is based on the Fourier formulation of a Lagrangian-Green's function method that provides an accurate and efficient technique for the solution of the parallel heat transport equation in the presence of harmonic power modulation. The numerical results presented provide conclusive evidence that even in the absence of magnetic flux surfaces, chaotic magnetic field configurations with intermediate levels of stochasticity exhibit transport barriers to modulated heat pulse propagation. In particular, high-order islands andmore » remnants of destroyed flux surfaces (Cantori) act as partial barriers that slow down or even stop the propagation of heat waves at places where the magnetic field connection length exhibits a strong gradient. Results on modulated heat pulse propagation in fully stochastic fields and across magnetic islands are also presented. In qualitative agreement with recent experiments in large helical device and DIII-D, it is shown that the elliptic (O) and hyperbolic (X) points of magnetic islands have a direct impact on the spatio-temporal dependence of the amplitude of modulated heat pulses.« less

A leading edge heating array and a flat surface heating array: Final design. [for testing the thermal protection system of the space shuttle

NASA Technical Reports Server (NTRS)

1975-01-01

A heating array is described for testing full-scale sections of the leading edge and lower fuselage surfaces of the shuttle. The heating array was designed to provide a tool for development and acceptance testing of leading edge segments and large flat sections of the main body thermal protection system. The array was designed using a variable length module concept to meet test requirements using interchangeable components from one test configuration in another configuration. Heat generating modules and heat absorbing modules were employed to achieve the thermal gradient around the leading edge. A support was developed to hold the modules to form an envelope around a variety of leading edges; to supply coolant to each module; the support structure and to hold the modules in the flat surface heater configuration. An optical pyrometer system mounted within the array was designed to monitor specimen surface temperatures without altering the test article's surface.

Sodium Variable Conductance Heat Pipe for Radioisotope Stirling Systems

NASA Technical Reports Server (NTRS)

Tarau, Calin; Anderson, William G.; Walker, Kara

2009-01-01

In a Stirling radioisotope system, heat must continually be removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the converter stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, and also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) has been designed to allow multiple stops and restarts of the Stirling convertor in an Advanced Stirling Radioisotope Generator (ASRG). When the Stirling convertor is turned off, the VCHP will activate when the temperatures rises 30 C above the setpoint temperature. A prototype VCHP with sodium as the working fluid was fabricated and tested in both gravity aided and against gravity conditions for a nominal heater head temperature of 790 C. The results show very good agreement with the predictions and validate the model. The gas front was located at the exit of the reservoir when heater head temperature was 790 C while cooling was ON, simulating an operating Advanced Stirling Converter (ASC). When cooling stopped, the temperature increased by 30 C, allowing the gas front to move past the radiator, which transferred the heat to the case. After resuming the cooling flow, the front returned at the initial location turning OFF the VCHP. The against gravity working conditions showed a colder reservoir and faster transients.

Modeling a Thermoelectric Generator Applied to Diesel Automotive Heat Recovery

NASA Astrophysics Data System (ADS)

Espinosa, N.; Lazard, M.; Aixala, L.; Scherrer, H.

2010-09-01

Thermoelectric generators (TEGs) are outstanding devices for automotive waste heat recovery. Their packaging, lack of moving parts, and direct heat to electrical conversion are the main benefits. Usually, TEGs are modeled with a constant hot-source temperature. However, energy in exhaust gases is limited, thus leading to a temperature decrease as heat is recovered. Therefore thermoelectric properties change along the TEG, affecting performance. A thermoelectric generator composed of Mg2Si/Zn4Sb3 for high temperatures followed by Bi2Te3 for low temperatures has been modeled using engineering equation solver (EES) software. The model uses the finite-difference method with a strip-fins convective heat transfer coefficient. It has been validated on a commercial module with well-known properties. The thermoelectric connection and the number of thermoelements have been addressed as well as the optimum proportion of high-temperature material for a given thermoelectric heat exchanger. TEG output power has been estimated for a typical commercial vehicle at 90°C coolant temperature.

Silicon Carbide (SiC) Device and Module Reliability, Performance of a Loop Heat Pipe Subjected to a Phase-Coupled Heat Input to an Acceleration Field

DTIC Science & Technology

2016-05-01

AFRL-RQ-WP-TR-2016-0108 SILICON CARBIDE (SiC) DEVICE AND MODULE RELIABILITY Performance of a Loop Heat Pipe Subjected to a Phase-Coupled... Heat Input to an Acceleration Field Kirk L. Yerkes (AFRL/RQQI) and James D. Scofield (AFRL/RQQE) Flight Systems Integration Branch (AFRL/RQQI...CARBIDE (SiC) DEVICE AND MODULE RELIABILITY Performance of a Loop Heat Pipe Subjected to a Phase-Coupled Heat Input to an Acceleration Field 5a

A heat flux modulator from carbon nanotubes.

PubMed

Jiang, Shaohui; Zhang, Guang; Xia, Dan; Liu, Changhong; Fan, Shoushan

2015-08-28

For a heat flux modulator, the most difficult problem is that the main carriers named 'phonons' have little response to external fields. Of the existing studies on heat flux modulators, most were theoretical work and the materials systems for the theoretical calculations were artificial lattices. In this paper, we made a heat modulator with ultrathin buckypaper which was made of multi-layer carbon nanotube sheets overlapped together, and achieved an on/off ratio whose value was 1.41 using an pendent block in experiments without special optimizations. When the temperatures of the two sides were of appropriate values, we could even see a negative heat flux. Intuitively, the heat flux was tuned by the gap between the buckypaper and the pendent gate, and we observed that there was heat transferred to the pendent block. The structure of the modulator is similar to a CNT transistor with a contactless gate, hence this type of micromodulator will be easy to manufacture in the future.

Analysis of a Temperature-Controlled Exhaust Thermoelectric Generator During a Driving Cycle

NASA Astrophysics Data System (ADS)

Brito, F. P.; Alves, A.; Pires, J. M.; Martins, L. B.; Martins, J.; Oliveira, J.; Teixeira, J.; Goncalves, L. M.; Hall, M. J.

2016-03-01

Thermoelectric generators can be used in automotive exhaust energy recovery. As car engines operate under wide variable loads, it is a challenge to design a system for operating efficiently under these variable conditions. This means being able to avoid excessive thermal dilution under low engine loads and being able to operate under high load, high temperature events without the need to deflect the exhaust gases with bypass systems. The authors have previously proposed a thermoelectric generator (TEG) concept with temperature control based on the operating principle of the variable conductance heat pipe/thermosiphon. This strategy allows the TEG modules’ hot face to work under constant, optimized temperature. The variable engine load will only affect the number of modules exposed to the heat source, not the heat transfer temperature. This prevents module overheating under high engine loads and avoids thermal dilution under low engine loads. The present work assesses the merit of the aforementioned approach by analysing the generator output during driving cycles simulated with an energy model of a light vehicle. For the baseline evaporator and condenser configuration, the driving cycle averaged electrical power outputs were approximately 320 W and 550 W for the type-approval Worldwide harmonized light vehicles test procedure Class 3 driving cycle and for a real-world highway driving cycle, respectively.

Architectural innovation foresight of thermoelectric generator charger integrated portable power supply for portable consumer electronic device in metropolitan market: The case study of Thailand

NASA Astrophysics Data System (ADS)

Maolikul, S.; Kiatgamolchai, S.; Chavarnakul, T.

2012-06-01

In the context of information and communication technology (ICT) trend for worldwide individuals, social life becomes digital and portable consumer electronic devices (PCED) powered by conventional power supply from batteries have been evolving through miniaturization and various function integration. Thermoelectric generators (TEG) were hypothesized for its potential role of battery charger to serve the shining PCED market. Hence, this paper, mainly focusing at the metropolitan market in Thailand, aimed to conduct architectural innovation foresight and to develop scenarios on potential exploitation approach of PCED battery power supply with TEG charger converting power from ambient heat source adjacent to individual's daily life. After technical review and assessment for TEG potential and battery aspect, the business research was conducted to analyze PCED consumer behavior for their PCED utilization pattern, power supply lack problems, and encountering heat sources/sinks in 3 modes: daily life, work, and leisure hobbies. Based on the secondary data analysis from literature and National Statistical Office of Thailand, quantitative analysis was applied using the cluster probability sampling methodology, statistically, with the sample size of 400 at 0.05 level of significance. In addition, the qualitative analysis was conducted to emphasize the rationale of consumer's behavior using in-depth qualitative interview. Scenario planning technique was also used to generate technological and market trend foresight. Innovation field and potential scenario for matching technology with market was proposed in this paper. The ingredient for successful commercialization of battery power supply with TEG charger for PCED market consists of 5 factors as follows: (1) PCED characteristic, (2) potential ambient heat sources/sinks, (3) battery module, (4) power management module, and the final jigsaw (5) characteristic and adequate arrangement of TEG modules. The foresight outcome for the potential innovations represents a case study in the pilot commercialization of TEG technology for some interesting niche markets in metropolitan area of Thailand, and, thus, can be the clue for product development related to TEG for market-driven application in other similar requirement conditions and contexts as well.

Examination of a Thermally Viable Structure for an Unconventional Uni-Leg Mg2Si Thermoelectric Power Generator

NASA Astrophysics Data System (ADS)

Sakamoto, Tatsuya; Iida, Tsutomu; Taguchi, Yutaka; Kurosaki, Shota; Hayatsu, Yusuke; Nishio, Keishi; Kogo, Yasuo; Takanashi, Yoshifumi

2012-06-01

We have fabricated an unconventional uni-leg structure thermoelectric generator (TEG) element using quad thermoelectric (TE) chips of Sb-doped n-Mg2Si, which were prepared by a plasma-activated sintering process. The power curve characteristics, the effect of aging up to 500 h, and the thermal gradients at several points on the module were investigated. The observed maximum output power with the heat source at 975 K and the heat sink at 345 K was 341 mW, from which the Δ T for the TE chip was calculated to be about 333 K. In aging testing in air ambient, a remarkable feature of the results was that there was no notable change from the initial resistance of the TEG module for as long as 500 h. The thermal distribution for the fabricated uni-leg TEG element was analyzed by finite-element modeling using ANSYS software. To tune the calculation parameters of ANSYS, such as the thermal conductance properties of the corresponding coupled materials in the module, precise measurements of the temperature at various probe points on the module were made. Then, meticulous verification between the measured temperature values and the results calculated by ANSYS was carried out to optimize the parameters.

Passive thermosyphon solar heating and cooling module with supplementary heating

NASA Technical Reports Server (NTRS)

1977-01-01

A collection of three quarterly reports from Sigma Research, Inc., covering progress and status from January through September 1977 are presented. Three heat exchangers are developed for use in a solar heating and cooling system for installation into single-family dwellings. Each exchanger consists of one heating and cooling module and one submerged electric water heating element.

Energy Efficiency and Performance Limiting Effects in Thermo-Osmotic Energy Conversion from Low-Grade Heat.

PubMed

Straub, Anthony P; Elimelech, Menachem

2017-11-07

Low-grade heat energy from sources below 100 °C is available in massive quantities around the world, but cannot be converted to electricity effectively using existing technologies due to variability in the heat output and the small temperature difference between the source and environment. The recently developed thermo-osmotic energy conversion (TOEC) process has the potential to harvest energy from low-grade heat sources by using a temperature difference to create a pressurized liquid flux across a membrane, which can be converted to mechanical work via a turbine. In this study, we perform the first analysis of energy efficiency and the expected performance of the TOEC technology, focusing on systems utilizing hydrophobic porous vapor-gap membranes and water as a working fluid. We begin by developing a framework to analyze realistic mass and heat transport in the process, probing the impact of various membrane parameters and system operating conditions. Our analysis reveals that an optimized system can achieve heat-to-electricity energy conversion efficiencies up to 4.1% (34% of the Carnot efficiency) with hot and cold working temperatures of 60 and 20 °C, respectively, and an operating pressure of 5 MPa (50 bar). Lower energy efficiencies, however, will occur in systems operating with high power densities (>5 W/m 2 ) and with finite-sized heat exchangers. We identify that the most important membrane properties for achieving high performance are an asymmetric pore structure, high pressure resistance, a high porosity, and a thickness of 30 to 100 μm. We also quantify the benefits in performance from utilizing deaerated water streams, strong hydrodynamic mixing in the membrane module, and high heat exchanger efficiencies. Overall, our study demonstrates the promise of full-scale TOEC systems to extract energy from low-grade heat and identifies key factors for performance optimization moving forward.

Precipitation Processes Derived from TRMM Satellite Data, Cloud Resolving Model and Field Campaigns

NASA Technical Reports Server (NTRS)

Tao, W.-K.; Lang, S.; Simpson, J.; Meneghini, R.; Halverson, J.; Johnson, R.; Adler, R.; Einaudi, Franco (Technical Monitor)

2001-01-01

Rainfall is a key link in the hydrologic cycle and is a primary heat source for the atmosphere. The vertical distribution of latent-heat release, which is accompanied by rainfall, modulates the large-scale circulations of the tropics and in turn can impact midlatitude weather. This latent heat release is a consequence of phase changes between vapor, liquid. and solid water. Present large-scale weather and climate models can simulate cloud latent heat release only crudely thus reducing their confidence in predictions on both global and regional scales. In this paper, NASA Tropical Rainfall Measuring (TRMM) precipitation radar (PR) derived rainfall information and the Goddard Convective and Stratiform Heating (CSH) algorithm used to estimate the four-dimensional structure of global monthly latent heating and rainfall profiles over the global tropics from December 1997 to October 2000. Rainfall latent heating and radar reflectively structure between ENSO (1997-1998 winter) and non-ENSO (1998-1999 winter) periods are examined and compared. The seasonal variation of heating over various geographic locations (i.e. Indian ocean vs west Pacific; Africa vs S. America) are also analyzed. In addition, the relationship between rainfall latent heating maximum heating level), radar reflectively and SST are examined.

Heat loss analysis-based design of a 12 MW wind power generator module having an HTS flux pump exciter

NASA Astrophysics Data System (ADS)

Sung, Hae-Jin; Go, Byeong-Soo; Jiang, Zhenan; Park, Minwon; Yu, In-Keun

2016-11-01

The development of an effective high-temperature superconducting (HTS) generator is currently a research focus; however, the reduction of heat loss of a large-scale HTS generator is a challenge. This study deals with a heat loss analysis-based design of a 12 MW wind power generator module having an HTS flux pump exciter. The generator module consists of an HTS rotor of the generator and an HTS flux pump exciter. The specifications of the module were described, and the detailed configuration of the module was illustrated. For the heat loss analysis of the module, the excitation loss of the flux pump exciter, eddy current loss of all of the structures in the module, radiation loss, and conduction loss of an HTS coil supporter were assessed using a 3D finite elements method program. In the case of the conduction loss, different types of the supporters were compared to find out the supporter of the lowest conduction loss in the module. The heat loss analysis results of the module were reflected in the design of the generator module and discussed in detail. The results will be applied to the design of large-scale superconducting generators for wind turbines including a cooling system.

Metallurgy and Heat Treating. Welding Module 7. Instructor's Guide.

ERIC Educational Resources Information Center

Missouri Univ., Columbia. Instructional Materials Lab.

This guide is intended to assist vocational educators in teaching a three-unit module in metallurgy and heat treating. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The basic principles of metallurgy and heat treatment and techniques for…

Rugged microelectronic module package supports circuitry on heat sink

NASA Technical Reports Server (NTRS)

Johnson, A. L.

1966-01-01

Rugged module package for thin film hybrid microcircuits incorporated a rigid, thermally conductive support structure, which serves as a heat sink, and a lead wire block in which T-shaped electrical connectors are potted. It protects the circuitry from shock and vibration loads, dissipates internal heat, and simplifies electrical connections between adjacent modules.

Three-Dimensional Finite-Element Simulation for a Thermoelectric Generator Module

NASA Astrophysics Data System (ADS)

Hu, Xiaokai; Takazawa, Hiroyuki; Nagase, Kazuo; Ohta, Michihiro; Yamamoto, Atsushi

2015-10-01

A three-dimensional closed-circuit numerical model of a thermoelectric generator (TEG) module has been constructed with COMSOL® Multiphysics to verify a module test system. The Seebeck, Peltier, and Thomson effects and Joule heating are included in the thermoelectric conversion model. The TEG model is employed to simulate the operation of a 16-leg TEG module based on bismuth telluride with temperature-dependent material properties. The module is mounted on a test platform, and simulated by combining the heat conduction process and thermoelectric conversion process. Simulation results are obtained for the terminal voltage, output power, heat flow, and efficiency as functions of the electric current; the results are compared with measurement data. The Joule and Thomson heats in all the thermoelectric legs, as functions of the electric current, are calculated by finite-element volume integration over the entire legs. The Peltier heat being pumped at the hot side and released at the cold side of the module are also presented in relation to the electric current. The energy balance relations between heat and electricity are verified to support the simulation.

TRMM Latent Heating Retrieval and Comparisons with Field Campaigns and Large-Scale Analyses

NASA Technical Reports Server (NTRS)

Tao, Wei-Kuo; Takayabu, Yukuri; Lang, S.; Shige, S.; Olson, W.; Hou, A.; Jiang, X.; Zhang, C.; Lau, W.; Krishnamurti, T.;

Thermal stress response of General Purpose Heat Source (GPHS) aeroshell material

NASA Technical Reports Server (NTRS)

Grinberg, I. M.; Hulbert, L. E.; Luce, R. G.

1980-01-01

A thermal stress test was conducted to determine the ability of the GPHS aeroshell 3 D FWPF material to maintain physical integrity when exposed to a severe heat flux such as would occur from prompt reentry of GPHS modules. The test was performed in the Giant Planetary Facility at NASA's Ames Research Center. Good agreement was obtained between the theoretical and experimental results for both temperature and strain time histories. No physical damage was observed in the test specimen. These results provide initial corroboration both of the analysis techniques and that the GPHS reentry member will survive the reentry thermal stress levels expected.

Low exhaust temperature electrically heated particulate matter filter system

DOEpatents

Gonze, Eugene V [Pinckney, MI; Paratore, Jr., Michael J.; Bhatia, Garima [Bangalore, IN

2012-02-14

A system includes a particulate matter (PM) filter, a sensor, a heating element, and a control module. The PM filter includes with an upstream end that receives exhaust gas, a downstream end and multiple zones. The sensor detects a temperature of the exhaust gas. The control module controls current to the heating element to convection heat one of the zones and initiate a regeneration process. The control module selectively increases current to the heating element relative to a reference regeneration current level when the temperature is less than a predetermined temperature.

Ash reduction system using electrically heated particulate matter filter

DOEpatents

Gonze, Eugene V [Pinckney, MI; Paratore, Jr., Michael J; He, Yongsheng [Sterling Heights, MI

2011-08-16

A control system for reducing ash comprises a temperature estimator module that estimates a temperature of an electrically heated particulate matter (PM) filter. A temperature and position estimator module estimates a position and temperature of an oxidation wave within the electrically heated PM filter. An ash reduction control module adjusts at least one of exhaust flow, fuel and oxygen levels in the electrically heated PM filter to adjust a position of the oxidation wave within the electrically heated PM filter based on the oxidation wave temperature and position.

NaK Variable Conductance Heat Pipe for Radioisotope Stirling Systems

NASA Technical Reports Server (NTRS)

Tarau, Calin; Anderson, William G.; Walker, Kara

2008-01-01

In a Stirling radioisotope power system, heat must continually be removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides most of this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending use of that convertor for the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) was designed to allow multiple stops and restarts of the Stirling convertor. In the design of the VCHP for the Advanced Stirling Radioisotope Generator, the VCHP reservoir temperature can vary between 40 and 120 C. While sodium, potassium, or cesium could be used as the working fluid, their melting temperatures are above the minimum reservoir temperature, allowing working fluid to freeze in the reservoir. In contrast, the melting point of NaK is -12 C, so NaK can't freeze in the reservoir. One potential problem with NaK as a working fluid is that previous tests with NaK heat pipes have shown that NaK heat pipes can develop temperature non-uniformities in the evaporator due to NaK's binary composition. A NaK heat pipe was fabricated to measure the temperature non-uniformities in a scale model of the VCHP for the Stirling Radioisotope system. The temperature profiles in the evaporator and condenser were measured as a function of operating temperature and power. The largest delta T across the condenser was 2S C. However, the condenser delta T decreased to 16 C for the 775 C vapor temperature at the highest heat flux applied, 7.21 W/ square cm. This decrease with increasing heat flux was caused by the increased mixing of the sodium and potassium in the vapor. This temperature differential is similar to the temperature variation in this ASRG heat transfer interface without a heat pipe, so NaK can be used as the VCHP working fluid.

Performance of a thermionic converter module utilizing emitter and collector heat pipes

NASA Technical Reports Server (NTRS)

Kroeger, E. W.; Morris, J. F.; Miskolczy, G.; Lieb, D. P.; Goodale, D. B.

1978-01-01

A thermionic converter module simulating a configuration for an out-of-core thermionic nuclear reactor was designed, fabricated, and tested. The module consists of three cylindrical thermionic converters. The tungsten emitter of the converter is heated by a tungsten, lithium heat pipe. The emitter heat pipes are immersed in a furnace, insulated by MULTI-FOIL thermal insulation, and heated by tungsten radiation filaments. The performance of each thermionic converter was characterized before assembly into the module. Dynamic voltage, current curves were taken using a 60 Hz sweep and computerized data acquisition over a range of emitter, collector, and cesium-reservoir temperatures. An output power of 215 W was observed at an emitter temperature of 1750 K and a collector temperature of 855 K for a two diode module. With a three diode module, an output power of 270 W was observed at an average emitter temperature of 1800 K and a Collector temperature of 875 K.

Modular Isotopic Thermoelectric Generator

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

Schock, Alfred

1981-01-01

Advanced RTG concepts utilizing improved thermoelectric materials and converter concepts are under study at Fairchild for DOE. The design described here is based on DOE's newly developed radioisotope heat source, and on an improved silicon-germanium material and multicouple converter module under development at Syncal. Fairchild's assignment was to combine the above into an attractive power system for use in space, and to assess the specific power and other attributes of that design.

Microtube strip heat exchanger

NASA Astrophysics Data System (ADS)

Doty, F. D.

1990-12-01

Doty Scientific (DSI) believes their microtube-strip heat exchanger will contribute significantly to the following: (1) the closed Brayton cycles being pursued at MIT, NASA, and elsewhere; (2) reverse Brayton cycle cryocoolers, currently being investigated by NASA for space missions, being applied to MRI superconducting magnets; and (3) high-efficiency cryogenic gas separation schemes for CO2 removal from exhaust stacks. The goal of this current study is to show the potential for substantial progress in high-effectiveness, low-cost, gas-to-gas heat exchangers for diverse applications at temperatures from below 100 K to above 1000 K. To date, the highest effectiveness measured is about 98 percent and relative pressure drops below 0.1 percent with a specific conductance of about 45 W/kgK are reported. During the pre-award period DSI built and tested a 3-module heat exchanger bank using 103-tube microtube strip (MTS) modules. To add to their analytical capabilities, DSI has acquired computational fluid dynamics (CFD) software. This report describes the pre-award work and the status of the ten tasks of the current project, which are: analyze flow distribution and thermal stresses within individual modules; design a heat exchanger bank of ten modules with 400 microtube per module; obtain production quality tubestrip die and AISI 304 tubestrips; obtain production quality microtubing; construct revised MTS heat exchanger; construct dies and fixtures for prototype heat exchanger; construct 100 MTS modules; assemble 8 to 10 prototype MTS heat exchangers; test prototype MTS heat exchanger; and verify test through independent means.

Hysteresis and fast timescales in transport relations of toroidal plasmas

NASA Astrophysics Data System (ADS)

Itoh, K.; Itoh, S.-I.; Ida, K.; Inagaki, S.; Kamada, Y.; Kamiya, K.; Dong, J. Q.; Hidalgo, C.; Evans, T.; Ko, W. H.; Park, H.; Tokuzawa, T.; Kubo, S.; Kobayashi, T.; Kosuga, Y.; Sasaki, M.; Yun, G. S.; Song, S. D.; Kasuya, N.; Nagashima, Y.; Moon, C.; Yoshinuma, M.; Makino, R.; Tsujimura, T.; Tsuchiya, H.; Stroth, U.

2017-10-01

This article assesses current understanding of hysteresis in transport relations, and its impact on the field. The rapid changes of fluxes compared to slow changes of plasma parameters are overviewed for both core and edge plasmas. The modulation ECH experiment is explained, in which the heating power cycles on-and-off periodically, revealing hysteresis and fast changes in the gradient-flux relation. The key finding is that hystereses were observed simultaneously in both the the gradient-flux and gradient-fluctuation relations. Hysteresis with rapid timescale exists in the channels of energy, electron and impurity densities, and plausibly in momentum. Advanced methods of data analysis are explained. Transport hysteresis can be studied by observing the higher harmonics of temperature perturbation δ Tm in heating modulation experiments. The hysteresis introduces the term δ Tm , which depends on the harmonic number m in an algebraic manner (not exponential decay). Next, the causes of hysteresis and its fast timescale are discussed. The nonlocal-in-space coupling works here, but does not suffice. One mechanism for ‘the heating heats turbulence’ is that the external source S in phase space for heating has its fluctuation in turbulent plasma. This coupling can induce the direct input of heating power into fluctuations. The height of the jump in transport hysteresis is smaller for heavier hydrogen isotopes, and could be one of the origins of isotope effects on confinement. Finally, the impacts of transport hysteresis on the control system are assessed. Control systems must be designed so as to protect the system from sudden plasma loss.

Optical Coating Performance and Thermal Structure Design for Heat Reflectors of JWST Electronic Control Unit

NASA Technical Reports Server (NTRS)

Quijada, Manuel A.; Threat, Felix; Garrison, Matt; Perrygo, Chuck; Bousquet, Robert; Rashford, Robert

2008-01-01

The James Webb Space Telescope (JWST) consists of an infrared-optimized Optical Telescope Element (OTE) that is cooled down to 40 degrees Kelvin. A second adjacent component to the OTE is the Integrated Science Instrument Module, or ISIM. This module includes the electronic compartment, which provides the mounting surfaces and ambient thermally controlled environment for the instrument control electronics. Dissipating the 200 watts generated from the ISIM structure away from the OTE is of paramount importance so that the spacecraft's own heat does not interfere with the infrared light detected from distant cosmic sources. This technical challenge is overcome by a thermal subsystem unit that provides passive cooling to the ISIM control electronics. The proposed design of this thermal radiator consists of a lightweight structure made out of composite materials and low-emittance metal coatings. In this paper, we will present characterizations of the coating emittance, bidirectional reflectance, and mechanical structure design that will affect the performance of this passive cooling system.

Thermoelectric Generation Using Counter-Flows of Ideal Fluids

NASA Astrophysics Data System (ADS)

Meng, Xiangning; Lu, Baiyi; Zhu, Miaoyong; Suzuki, Ryosuke O.

2017-08-01

Thermoelectric (TE) performance of a three-dimensional (3-D) TE module is examined by exposing it between a pair of counter-flows of ideal fluids. The ideal fluids are thermal sources of TE module flow in the opposite direction at the same flow rate and generate temperature differences on the hot and cold surfaces due to their different temperatures at the channel inlet. TE performance caused by different inlet temperatures of thermal fluids are numerically analyzed by using the finite-volume method on 3-D meshed physical models and then compared with those using a constant boundary temperature. The results show that voltage and current of the TE module increase gradually from a beginning moment to a steady flow and reach a stable value. The stable values increase with inlet temperature of the hot fluid when the inlet temperature of cold fluid is fixed. However, the time to get to the stable values is almost consistent for all the temperature differences. Moreover, the trend of TE performance using a fluid flow boundary is similar to that of using a constant boundary temperature. Furthermore, 3-D contours of fluid pressure, temperature, enthalpy, electromotive force, current density and heat flux are exhibited in order to clarify the influence of counter-flows of ideal fluids on TE generation. The current density and heat flux homogeneously distribute on an entire TE module, thus indicating that the counter-flows of thermal fluids have high potential to bring about fine performance for TE modules.

Development of a thermal storage module using modified anhydrous sodium hydroxide

NASA Technical Reports Server (NTRS)

Rice, R. E.; Rowny, P. E.

1980-01-01

The laboratory scale testing of a modified anhydrous NaOH latent heat storage concept for small solar thermal power systems such as total energy systems utilizing organic Rankine systems is discussed. A diagnostic test on the thermal energy storage module and an investigation of alternative heat transfer fluids and heat exchange concepts are specifically addressed. A previously developed computer simulation model is modified to predict the performance of the module in a solar total energy system environment. In addition, the computer model is expanded to investigate parametrically the incorporation of a second heat exchange inside the module which will vaporize and superheat the Rankine cycle power fluid.

Assembly of opto-electronic module with improved heat sink

DOEpatents

Chan, Benson; Fortier, Paul Francis; Freitag, Ladd William; Galli, Gary T.; Guindon, Francois; Johnson, Glen Walden; Letourneau, Martial; Sherman, John H.; Tetreault, Real

2004-11-23

A heat sink for a transceiver optoelectronic module including dual direct heat paths and a structure which encloses a number of chips having a central web which electrically isolates transmitter and receiver chips from each other. A retainer for an optical coupler having a port into which epoxy is poured. An overmolded base for an optoelectronic module having epoxy flow controller members built thereon. Assembly methods for an optoelectronic module including gap setting and variation of a TAB bonding process.

Amorphous-silicon module hot-spot testing

NASA Technical Reports Server (NTRS)

Gonzalez, C. C.

1985-01-01

Hot spot heating occurs when cell short-circuit current is lower than string operating current. Amorphous cell hot spot are tested to develop the techniques required for performing reverse bias testing of amorphous cells. Also, to quantify the response of amorphous cells to reverse biasing. Guidelines are developed from testing for reducing hot spot susceptibility of amorphous modules and to develop a qualification test for hot spot testing of amorphous modules. It is concluded that amorphous cells undergo hot spot heating similarly to crystalline cells. Comparison of results obtained with submodules versus actual modules indicate heating levels lower in actual modules. Module design must address hot spot testing and hot spot qualification test conducted on modules showed no instabilities and minor cell erosion.

Thermoelectric heat exchange element

DOEpatents

Callas, James J.; Taher, Mahmoud A.

2007-08-14

A thermoelectric heat exchange module includes a first substrate including a heat receptive side and a heat donative side and a series of undulatory pleats. The module may also include a thermoelectric material layer having a ZT value of 1.0 or more disposed on at least one of the heat receptive side and the heat donative side, and an electrical contact may be in electrical communication with the thermoelectric material layer.

Preliminary design package for maxi-therm heat exchanger module

NASA Technical Reports Server (NTRS)

1978-01-01

Heat exchangers were developed for use in a solar heating and cooling system installed in a single family dwelling. Each of the three exchangers consisted of a heating and cooling module and a submersed electric water heating element. Information necessary to evaluate the preliminary design of the heat exchanger is presented in terms of the development and verification plans, performance specifications, installation and maintenance, and hazard analysis.

Modulated heat pulse propagation and partial transport barriers in chaotic magnetic fields

DOE PAGES

del-Castillo-Negrete, Diego; Blazevski, Daniel

2016-04-01

Direct numerical simulations of the time dependent parallel heat transport equation modeling heat pulses driven by power modulation in 3-dimensional chaotic magnetic fields are presented. The numerical method is based on the Fourier formulation of a Lagrangian-Green's function method that provides an accurate and efficient technique for the solution of the parallel heat transport equation in the presence of harmonic power modulation. The numerical results presented provide conclusive evidence that even in the absence of magnetic flux surfaces, chaotic magnetic field configurations with intermediate levels of stochasticity exhibit transport barriers to modulated heat pulse propagation. In particular, high-order islands and remnants of destroyed flux surfaces (Cantori) act as partial barriers that slow down or even stop the propagation of heat waves at places where the magnetic field connection length exhibits a strong gradient. The key parameter ismore » $$\\gamma=\\sqrt{\\omega/2 \\chi_\\parallel}$$ that determines the length scale, $$1/\\gamma$$, of the heat wave penetration along the magnetic field line. For large perturbation frequencies, $$\\omega \\gg 1$$, or small parallel thermal conductivities, $$\\chi_\\parallel \\ll 1$$, parallel heat transport is strongly damped and the magnetic field partial barriers act as robust barriers where the heat wave amplitude vanishes and its phase speed slows down to a halt. On the other hand, in the limit of small $$\\gamma$$, parallel heat transport is largely unimpeded, global transport is observed and the radial amplitude and phase speed of the heat wave remain finite. Results on modulated heat pulse propagation in fully stochastic fields and across magnetic islands are also presented. In qualitative agreement with recent experiments in LHD and DIII-D, it is shown that the elliptic (O) and hyperbolic (X) points of magnetic islands have a direct impact on the spatio-temporal dependence of the amplitude and the time delay of modulated heat pulses.« less

Power Generation Evaluated on a Bismuth Telluride Unicouple Module

NASA Astrophysics Data System (ADS)

Hu, Xiaokai; Nagase, Kazuo; Jood, Priyanka; Ohta, Michihiro; Yamamoto, Atsushi

2015-06-01

The power generated by a thermoelectric unicouple module made of Bi2Te3 alloy was evaluated by use of a newly developed instrument. An electrical load was connected to the module, and the terminal voltage and output power of the module were obtained by altering electric current. Water flow was used to cool the cold side of the module and for heat flow measurement, by monitoring inlet and outlet temperatures. When the electric current was increased, heat flow was enhanced as a result of the Peltier effect and Joule heating. Voltage, power, heat flow, and efficiency as functions of current were determined for hot-side temperatures from 50 to 220°C. Maximum power output and peak conversion efficiency could thus be easily derived for each temperature.

Power Generator with Thermo-Differential Modules

NASA Technical Reports Server (NTRS)

Saiz, John R.; Nguyen, James

2010-01-01

A thermoelectric power generator consists of an oven box and a solar cooker/solar reflector unit. The solar reflector concentrates sunlight into heat and transfers the heat into the oven box via a heat pipe. The oven box unit is surrounded by five thermoelectric modules and is located at the bottom end of the solar reflector. When the heat is pumped into one side of the thermoelectric module and ejected from the opposite side at ambient temperatures, an electrical current is produced. Typical temperature accumulation in the solar reflector is approximately 200 C (392 F). The heat pipe then transfers heat into the oven box with a loss of about 40 percent. At the ambient temperature of about 20 C (68 F), the temperature differential is about 100 C (180 F) apart. Each thermoelectric module, generates about 6 watts of power. One oven box with five thermoelectric modules produces about 30 watts. The system provides power for unattended instruments in remote areas, such as space colonies and space vehicles, and in polar and other remote regions on Earth.

A compact self-flowing lithium system for use in an industrial neutron source

NASA Astrophysics Data System (ADS)

Kalathiparambil, Kishor Kumar; Szott, Matthew; Jurczyk, Brian; Ahn, Chisung; Ruzic, David

2016-10-01

A compact trench module to flow liquid lithium in closed loops for handling high heat and particle flux have been fabricated and tested at UIUC. The module was designed to demonstrate the proof of concept in utilizing liquid metals for two principal objectives: i) as self-healing low Z plasma facing components, which is expected to solve the issues facing the current high Z components and ii) using flowing lithium as an MeV-level neutron source. A continuously flowing lithium loop ensures a fresh lithium interface and also accommodate a higher concentration of D, enabling advanced D-Li reactions without using any radioactive tritium. Such a system is expected to have a base yield of 10e7 n/s. For both the applications, the key success factor of the module is attaining the necessary high flow velocity of the lithium especially over the impact area, which will be the disruptive plasma events in fusion reactors and the incident ion beam for the neutron beam source. This was achieved by the efficient shaping of the trenches to exploit the nozzle effect in liquid flow. The compactness of the module, which can also be scaled as desired, was fulfilled by the use of high Tc permanent magnets and air cooled channels attained the necessary temperature gradient for driving the lithium. The design considerations and parameters, experimental arrangements involving lithium filling and attaining flow, data and results obtained will be elaborated. DOE SBIR project DE-SC0013861.

Electro-statically controllable graphene local heater

NASA Astrophysics Data System (ADS)

Wang, Hui-Shan; Deng, Lian-Wen; Li, Lei; Sun, Qiu-Juan; Xie, Hong; Wang, Hao-Min

2018-03-01

We report on current-induced thermal power investigation of graphene nanostructure for potential local-heating applications. It is found that the efficiency of heating can be greatly improved if graphene is patterned into structures with narrow width and long channel. In a narrow graphene-ribbon, the Joule heating power exhibits an obvious dependence on the back-gate voltage. By monitoring Raman spectra, the temperature of graphene-ribbon can be determined. The temperature of graphene-ribbon is modulated by the electric field effect when the sample is sourced with a relatively high current. Project supported by the National Key R&D Program of China (Grant No. 2017YFF0206106), the Chinese Academy of Sciences (Grant No. XDB04040300), the National Natural Science Foundation of China (Grant No. 51772317), and the Science and Technology Commission of Shanghai Municipality, China (Grant No. 16ZR1442700).

Extended development of a sodium hydroxide thermal energy storage module

NASA Technical Reports Server (NTRS)

Rice, R. E.; Rowny, P. E.; Cohen, B. M.

1980-01-01

The post-test evaluation of a single heat exchanger sodium hydroxide thermal energy storage module for use in solar electric generation is reported. Chemical analyses of the storage medium used in the experimental model are presented. The experimental verification of the module performance using an alternate heat transfer fluid, Caloria HT-43, is described. Based on these results, a design analysis of a dual heat exchanger concept within the storage module is presented. A computer model and a reference design for the dual system (storage working fluid/power cycle working fluid) were completed. The dual system is estimated to have a capital cost of approximately one half that of the single heat exchanger concept.

Environmental testing of CIS based modules

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

Willett, D.

1995-11-01

This report describes environmental testing of Siemen`s CIS modules. Charts and diagrams are presented on data concerning: temporary power loss of laminated mini-modules; the 50 thermal cycle test; the 10 humidity freeze cycle test; results after 1000 hours of exposure to damp heat; and interconnect test structures in damp heat testing. It is concluded that moisture ingress causes permanent increases in the series resistance of modules, and that improved packaging is needed for better high humidity reliability. Also, dry dark heat caused temporary power losses which were recovered in sunlight.

Installation package maxi-therm S-101 heating module

NASA Technical Reports Server (NTRS)

1977-01-01

The installation, operation and maintenance of the Maxi-Therm S-101 Thermosypnon Heating Module is described. The Maxi-Therm S-101 is a packaged unit, complete with air filter, blower, electrical controls, and a thermosyphon liquid to air heat exchanger. It is intended for use in residential solar heating systems and can utilize off-peak electrical power.

Energy-Storage Modules for Active Solar Heating and Cooling

NASA Technical Reports Server (NTRS)

Parker, J. C.

1982-01-01

34 page report describes a melting salt hydrate that stores 12 times as much heat as rocks and other heavy materials. Energy is stored mostly as latent heat; that is, heat that can be stored and recovered without any significant change in temperature. Report also describes development, evaluation and testing of permanently sealed modules containing salt hydrate mixture.

Pika: A snow science simulation tool built using the open-source framework MOOSE

NASA Astrophysics Data System (ADS)

Slaughter, A.; Johnson, M.

2017-12-01

The Department of Energy (DOE) is currently investing millions of dollars annually into various modeling and simulation tools for all aspects of nuclear energy. An important part of this effort includes developing applications based on the open-source Multiphysics Object Oriented Simulation Environment (MOOSE; mooseframework.org) from Idaho National Laboratory (INL).Thanks to the efforts of the DOE and outside collaborators, MOOSE currently contains a large set of physics modules, including phase-field, level set, heat conduction, tensor mechanics, Navier-Stokes, fracture and crack propagation (via the extended finite-element method), flow in porous media, and others. The heat conduction, tensor mechanics, and phase-field modules, in particular, are well-suited for snow science problems. Pika--an open-source MOOSE-based application--is capable of simulating both 3D, coupled nonlinear continuum heat transfer and large-deformation mechanics applications (such as settlement) and phase-field based micro-structure applications. Additionally, these types of problems may be coupled tightly in a single solve or across length and time scales using a loosely coupled Picard iteration approach. In addition to the wide range of physics capabilities, MOOSE-based applications also inherit an extensible testing framework, graphical user interface, and documentation system; tools that allow MOOSE and other applications to adhere to nuclear software quality standards. The snow science community can learn from the nuclear industry and harness the existing effort to build simulation tools that are open, modular, and share a common framework. In particular, MOOSE-based multiphysics solvers are inherently parallel, dimension agnostic, adaptive in time and space, fully coupled, and capable of interacting with other applications. The snow science community should build on existing tools to enable collaboration between researchers and practitioners throughout the world, and advance the state-of-the-art in line with other scientific research efforts.

Dynamical heat transport amplification in a far-field thermal transistor of VO{sub 2} excited with a laser of modulated intensity

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

Ordonez-Miranda, Jose, E-mail: jose.ordonez@cnrs.pprime.fr; Ezzahri, Younès; Drevillon, Jérémie

2016-05-28

Far-field radiative heat transport in a thermal transistor made up of a vanadium dioxide base excited with a laser of modulated intensity is analytically studied and optimized. This is done by solving the equation of energy conservation for the steady-state and modulated components of the temperature and heat fluxes that the base exchanges with the collector and emitter. The thermal bistability of VO{sub 2} is used to find an explicit condition on the laser intensity required to maximize these heat fluxes to values higher than the incident flux. For a 1 μm-thick base heated with a modulation frequency of 0.5 Hz, itmore » is shown that both the DC and AC components of the heat fluxes are about 4 times the laser intensity, while the AC temperature remains an order of magnitude smaller than the DC one at around 343 K. Higher AC heat fluxes are obtained for thinner bases and/or lower frequencies. Furthermore, we find that out of the bistability temperatures associated with the dielectric-to-metal and metal-to-dielectric transitions of VO{sub 2}, the amplification of the collector-to-base and base-to-emitter heat fluxes is still possible, but at modulation frequencies lower than 0.1 Hz.« less

Heat Pipe-Assisted Thermoelectric Power Generation Technology for Waste Heat Recovery

NASA Astrophysics Data System (ADS)

Jang, Ju-Chan; Chi, Ri-Guang; Rhi, Seok-Ho; Lee, Kye-Bock; Hwang, Hyun-Chang; Lee, Ji-Su; Lee, Wook-Hyun

2015-06-01

Currently, large amounts of thermal energy dissipated from automobiles are emitted through hot exhaust pipes. This has resulted in the need for a new efficient recycling method to recover energy from waste hot exhaust gas. The present experimental study investigated how to improve the power output of a thermoelectric generator (TEG) system assisted by a wickless loop heat pipe (loop thermosyphon) under the limited space of the exhaust gas pipeline. The present study shows a novel loop-type heat pipe-assisted TEG concept to be applied to hybrid vehicles. The operating temperature of a TEG's hot side surface should be as high as possible to maximize the Seebeck effect. The present study shows a novel TEG concept of transferring heat from the source to the sink. This technology can transfer waste heat to any local place with a loop-type heat pipe. The present TEG system with a heat pipe can transfer heat and generate an electromotive force power of around 1.3 V in the case of 170°C hot exhaust gas. Two thermoelectric modules (TEMs) for a conductive block model and four Bi2Te3 TEMs with a heat pipe-assisted model were installed in the condenser section. Heat flows to the condenser section from the evaporator section connected to the exhaust pipe. This novel TEG system with a heat pipe can be placed in any location on an automobile.

Membrane module assembly

DOEpatents

Kaschemekat, Jurgen

1994-01-01

A membrane module assembly adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation.

Performance of OSC's initial Amtec generator design, and comparison with JPL's Europa Orbiter goals

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

Schock, A.; Noravian, H.; Or, C.

1998-07-01

The procedure for the analysis (with overpotential correction) of multitube AMTEC (Alkali Metal Thermal-to-Electrical Conversion) cells described in Paper IECEC 98-243 was applied to a wide range of multicell radioisotope space power systems. System design options consisting of one or two generators, each with 2, 3, or 4 stacked GPHS (General Purpose Heat Source) modules, identical to those used on previous NASA missions, were analyzed and performance-mapped. The initial generators analyzed by OSC had 8 AMTEC cells on each end of the heat source stack, with five beta-alumina solid electrolyte (BASE) tubes per cell. The heat source and converters inmore » the Orbital generator designs are embedded in a thermal insulation system consisting of Min-K fibrous insulation surrounded by graded-length molybdenum multifoils. Detailed analyses in previous Orbital studies found that such an insulation system could reduce extraneous heat losses to about 10%. For the above design options, the present paper presents the system mass and performance (i.e., the EOM system efficiency and power output and the BOM evaporator and clad temperatures) for a wide range of heat inputs and load voltages, and compares the results with JPL's preliminary goals for the Europa Orbiter mission to be launched in November 2003. The analytical results showed that the initial 16-cell generator designs resulted in either excessive evaporator and clad temperatures and/or insufficient power outputs to meet the JPL-specified mission goals. The computed performance of modified OSC generators with different numbers of AMTEC cells, cell diameters, cell lengths, cell materials, BASE tube lengths, and number of tubes per cell are described in Paper IECEC.98.245 in these proceedings.« less

Designing and Testing Energy Harvesters Suitable for Renewable Power Sources

NASA Astrophysics Data System (ADS)

Synkiewicz, B.; Guzdek, P.; Piekarski, J.; Zaraska, K.

2016-01-01

Energy harvesters convert waste power (heat, light and vibration) directly to electric power . Fast progress in their technology, design and areas of application (e.g. “Internet of Things”) has been observed recently. Their effectiveness is steadily growing which makes their application to powering sensor networks with wireless data transfer reasonable. The main advantage is the independence from wired power sources, which is especially important for monitoring state of environmental parameters. In this paper we describe the design and realization of a gas sensor monitoring CO level (powered by TEG) and two, designed an constructed in ITE, autonomous power supply modules powered by modern photovoltaic cells.

Sodium VCHP with Carbon-Carbon Radiator for Radioisotope Stirling Systems

NASA Astrophysics Data System (ADS)

Tarau, Calin; Anderson, William G.; Miller, William O.; Ramirez, Rogelio

2010-01-01

In a Stirling radioisotope system, heat must continually be removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling converter normally provides this cooling. If the Stirling convertor stops in the current system the insulation is designed to spoil, preventing damage to the GPHS at the cost of an earlier termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to allow multiple stops and restarts of the Stirling convertor. A sodium VCHP with a Haynes 230 envelope was designed and fabricated for the Advanced Stirling Radioisotope Generator (ASRG), with a baseline 850° C heater head temperature. When the Stirling convertor is stopped, the heat from the GPHS is rejected to the Cold Side Adapter Flange using a low-mass, carbon-carbon radiator. The VCHP is designed to activate with a AT of 30° C. The 880° C temperature when the Stirling convertor is stopped is high enough to avoid risking standard ASRG operation, but low enough to save most of the heater head life. The VCHP has low mass and low thermal losses for normal operation. The design has been modified from an earlier, stainless steel prototype with a nickel radiator. In addition to replacing the nickel radiator with a low mass carbon-carbon radiator, the radiator location has been moved from the ASRG case to the cold side adapter flange. This flange already removes two-thirds of the heat during normal operation, so it is optimized to transfer heat to the case. The VCHP was successfully tested with a turn-on ΔT of 30° C in three orientations: horizontal, gravity-aided, and against gravity.

Spectrally Selective Mirrors with Combined Optical and Thermal Benefit for Photovoltaic Module Thermal Management

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

Slauch, Ian M.; Deceglie, Michael G.; Silverman, Timothy J.

Waste heat generated during daytime operation of a solar module will raise its temperature and reduce cell efficiency. In addition to thermalization and carrier recombination, one major source of excess heat in modules is the parasitic absorption of light with sub-bandgap energy. Parasitic absorption can be prevented if sub-bandgap radiation is reflected away from the module. We report on the design considerations and projected changes to module energy yield for photonic reflectors capable of reflecting a portion of sub-bandgap radiation while maintaining or improving transmission of light with energy greater than the semiconductor bandgap. Using a previously developed, self-consistent opto-electro-thermalmore » finite-element simulation, we calculate the total additional energy generated by a module, including various photonic reflectors, and decompose these benefits into thermal and optical effects. We show that the greatest total energy yield improvement comes from photonic mirrors designed for the outside of the glass, but that mirrors placed between the glass and the encapsulant can have significant thermal benefit. We then show that optimal photonic mirror design requires consideration of all angles of incidence, despite unequal amounts of radiation arriving at each angle. We find that optimized photonic mirrors will be omnidirectional in the sense that they have beneficial performance, regardless of the angle of incidence of radiation. By fulfilling these criteria, photonic mirrors can be used at different geographic locations or different tilt angles than their original optimization conditions with only marginal changes in performance. We show designs that improve energy output in Golden, Colorado by 3.7% over a full year. This work demonstrates the importance of considering real-world irradiance and weather conditions when designing optical structures for solar applications.« less

Spectrally Selective Mirrors with Combined Optical and Thermal Benefit for Photovoltaic Module Thermal Management

DOE PAGES

Slauch, Ian M.; Deceglie, Michael G.; Silverman, Timothy J.; ...

2018-03-02

Waste heat generated during daytime operation of a solar module will raise its temperature and reduce cell efficiency. In addition to thermalization and carrier recombination, one major source of excess heat in modules is the parasitic absorption of light with sub-bandgap energy. Parasitic absorption can be prevented if sub-bandgap radiation is reflected away from the module. We report on the design considerations and projected changes to module energy yield for photonic reflectors capable of reflecting a portion of sub-bandgap radiation while maintaining or improving transmission of light with energy greater than the semiconductor bandgap. Using a previously developed, self-consistent opto-electro-thermalmore » finite-element simulation, we calculate the total additional energy generated by a module, including various photonic reflectors, and decompose these benefits into thermal and optical effects. We show that the greatest total energy yield improvement comes from photonic mirrors designed for the outside of the glass, but that mirrors placed between the glass and the encapsulant can have significant thermal benefit. We then show that optimal photonic mirror design requires consideration of all angles of incidence, despite unequal amounts of radiation arriving at each angle. We find that optimized photonic mirrors will be omnidirectional in the sense that they have beneficial performance, regardless of the angle of incidence of radiation. By fulfilling these criteria, photonic mirrors can be used at different geographic locations or different tilt angles than their original optimization conditions with only marginal changes in performance. We show designs that improve energy output in Golden, Colorado by 3.7% over a full year. This work demonstrates the importance of considering real-world irradiance and weather conditions when designing optical structures for solar applications.« less

SHIPPING CONTAINER FOR RADIOACTIVE MATERIAL

DOEpatents

Nachbar, H.D.; Biggs, B.B.; Tariello, P.J.; George, K.O.

1963-01-15

A shipping container is described for transponting a large number of radioactive nuclear fuel element modules which produce a substantial amount of heat. The container comprises a primary pressure vessel and shield, and a rotatable head having an access port that can be indexed with module holders in the container. In order to remove heat generated in the fuel eleme nts, a heat exchanger is arranged within the container and in contact with a heat exchange fluid therein. The heat exchanger communicates with additional external heat exchangers, which dissipate heat to the atmosphere. (AEC)

Sodium Heat Pipe Module Processing For the SAFE-100 Reactor Concept

NASA Technical Reports Server (NTRS)

Martin, James; Salvail, Pat

2003-01-01

To support development and hardware-based testing of various space reactor concepts, the Early Flight Fission-Test Facility (EFF-TF) team established a specialized glove box unit with ancillary systems to handle/process alkali metals. Recently, these systems have been commissioned with sodium supporting the fill of stainless steel heat pipe modules for use with a 100 kW thermal heat pipe reactor design. As part of this effort, procedures were developed and refined to govern each segment of the process covering: fill, leak check, vacuum processing, weld closeout, and final "wet in". A series of 316 stainless steel modules, used as precursors to the actual 321 stainless steel modules, were filled with 35 +/- 1 grams of sodium using a known volume canister to control the dispensed mass. Each module was leak checked to less than10(exp -10) std cc/sec helium and vacuum conditioned at 250 C to assist in the removal of trapped gases. A welding procedure was developed to close out the fill stem preventing external gases from entering the evacuated module. Finally the completed modules were vacuum fired at 750 C allowing the sodium to fully wet the internal surface and wick structure of the heat pipe module.

Sodium Heat Pipe Module Processing For the SAFE-100 Reactor Concept

NASA Astrophysics Data System (ADS)

Martin, James; Salvail, Pat

2004-02-01

To support development and hardware-based testing of various space reactor concepts, the Early Flight Fission-Test Facility (EFF-TF) team established a specialized glove box unit with ancillary systems to handle/process alkali metals. Recently, these systems have been commissioned with sodium supporting the fill of stainless steel heat pipe modules for use with a 100 kW thermal heat pipe reactor design. As part of this effort, procedures were developed and refined to govern each segment of the process covering: fill, leak check, vacuum processing, weld closeout, and final ``wet in''. A series of 316 stainless steel modules, used as precursors to the actual 321 stainless steel modules, were filled with 35 +/-1 grams of sodium using a known volume canister to control the dispensed mass. Each module was leak checked to <10-10 std cc/sec helium and vacuum conditioned at 250 °C to assist in the removal of trapped gases. A welding procedure was developed to close out the fill stem preventing external gases from entering the evacuated module. Finally the completed modules were vacuum fired at 750 °C allowing the sodium to fully wet the internal surface and wick structure of the heat pipe module.

Design and fabrication of a high temperature leading edge heating array, phase 1

NASA Technical Reports Server (NTRS)

1972-01-01

Progress during a Phase 1 program to design a high temperature heating array is reported for environmentally testing full-scale shuttle leading edges (30 inch span, 6 to 15 inch radius) at flight heating rates and pressures. Heat transfer analyses of the heating array, individual modules, and the shuttle leading edge were performed, which influenced the array design, and the design, fabrication, and testing of a prototype heater module.

A process model for the heat-affected zone microstructure evolution in duplex stainless steel weldments: Part II. Application to electron beam welding

NASA Astrophysics Data System (ADS)

Hemmer, H.; Grong, Ø.; Klokkehaug, S.

2000-03-01

In the present investigation, a process model for electron beam (EB) welding of different grades of duplex stainless steels (i.e. SAF 2205 and 2507) has been developed. A number of attractive features are built into the original finite element code, including (1) a separate module for prediction of the penetration depth and distribution of the heat source into the plate, (2) adaptive refinement of the three-dimensional (3-D) element mesh for quick and reliable solution of the differential heat flow equation, and (3) special subroutines for calculation of the heat-affected zone (HAZ) microstructure evolution. The process model has been validated by comparison with experimental data obtained from in situ thermocouple measurements and optical microscope examinations. Subsequently, its aptness to alloy design and optimization of welding conditions for duplex stainless steels is illustrated in different numerical examples and case studies pertaining to EB welding of tubular joints.

Experimental evidence of body centered cubic iron in Earth's core

NASA Astrophysics Data System (ADS)

Hrubiak, R.; Meng, Y.; Shen, G.

2017-12-01

The Earth's core is mainly composed of iron. While seismic evidence has shown a liquid outer core and a solid inner core, the crystalline nature of the solid iron at the core condition remains debated, largely due to the difficulties in experimental determination of exact polymorphs at corresponding pressure-temperature conditions. We have examined crystal structures of iron up to 220 GPa and 6000 K with x-ray diffraction using a double-sided laser heating system at HPCAT, Advanced Photon Source. The iron sample is confined in a small chamber surrounded by single crystal MgO. The laser power can be modulated together with temperature measurements. The modulated heating of iron in an MgO single crystal matrix allows for microstructure analysis during heating and after the sample is quenched. We present experimental evidence of a body-centered-cubic (BCC) iron from about 100 GPa and 3000 K to at least 220 GPa and 4000 K. The observed BCC phase may be consistent with a theoretically predicted BCC phase that is dynamically stable in similar pressure-temperature conditions [1]. We will discuss the stability region of the BCC phase and the melting curve of iron and their implications in the nature of the Earth's inner core. References: A. B. Belonoshko et al., Nat. Geosci., 1-6 (2017).

Thermoelectric Oxide Modules (TOMs) for the Direct Conversion of Simulated Solar Radiation into Electrical Energy

PubMed Central

Tomeš, Petr; Trottmann, Matthias; Suter, Clemens; Aguirre, Myriam Heidi; Steinfeld, Aldo; Haueter, Philipp; Weidenkaff, Anke

2010-01-01

The direct conversion of concentrated high temperature solar heat into electrical energy was demonstrated with a series of four–leg thermoelectric oxide modules (TOM). These temperature stable modules were not yet optimized for high efficiency conversion, but served as proof-of-principle for high temperature conversion. They were constructed by connecting two p- (La1.98Sr0.02CuO4) and two n-type (CaMn0.98Nb0.02O3) thermoelements electrically in series and thermally in parallel. The temperature gradient ΔT was applied by a High–Flux Solar Simulator source (HFSS) which generates a spectrum similar to solar radiation. The influence of the graphite layer coated on the hot side of the Al2O3 substrate compared to the uncoated surface on ΔT, Pmax and η was studied in detail. The measurements show an almost linear temperature profile along the thermoelectric legs. The maximum output power of 88.8 mW was reached for a TOM with leg length of 5 mm at ΔT = 622 K. The highest conversion efficiency η was found for a heat flux of 4–8 W cm-2 and the dependence of η on the leg length was investigated.

Thermal control system. [removing waste heat from industrial process spacecraft

NASA Technical Reports Server (NTRS)

Hewitt, D. R. (Inventor)

1983-01-01

The temperature of an exothermic process plant carried aboard an Earth orbiting spacecraft is regulated using a number of curved radiator panels accurately positioned in a circular arrangement to form an open receptacle. A module containing the process is insertable into the receptacle. Heat exchangers having broad exterior surfaces extending axially above the circumference of the module fit within arcuate spacings between adjacent radiator panels. Banks of variable conductance heat pipes partially embedded within and thermally coupled to the radiator panels extend across the spacings and are thermally coupled to broad exterior surfaces of the heat exchangers by flanges. Temperature sensors monitor the temperature of process fluid flowing from the module through the heat exchanges. Thermal conduction between the heat exchangers and the radiator panels is regulated by heating a control fluid within the heat pipes to vary the effective thermal length of the heat pipes in inverse proportion to changes in the temperature of the process fluid.

Magnetically Modulated Heat Transport in a Global Simulation of Solar Magneto-convection

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

Cossette, Jean-Francois; Charbonneau, Paul; Smolarkiewicz, Piotr K.

We present results from a global MHD simulation of solar convection in which the heat transported by convective flows varies in-phase with the total magnetic energy. The purely random initial magnetic field specified in this experiment develops into a well-organized large-scale antisymmetric component undergoing hemispherically synchronized polarity reversals on a 40 year period. A key feature of the simulation is the use of a Newtonian cooling term in the entropy equation to maintain a convectively unstable stratification and drive convection, as opposed to the specification of heating and cooling terms at the bottom and top boundaries. When taken together, themore » solar-like magnetic cycle and the convective heat flux signature suggest that a cyclic modulation of the large-scale heat-carrying convective flows could be operating inside the real Sun. We carry out an analysis of the entropy and momentum equations to uncover the physical mechanism responsible for the enhanced heat transport. The analysis suggests that the modulation is caused by a magnetic tension imbalance inside upflows and downflows, which perturbs their respective contributions to heat transport in such a way as to enhance the total convective heat flux at cycle maximum. Potential consequences of the heat transport modulation for solar irradiance variability are briefly discussed.« less

Modulation of surface structure and catalytic properties of cerium oxide nanoparticles by thermal and microwave synthesis techniques

NASA Astrophysics Data System (ADS)

He, Jian; Zhou, Lan; Liu, Jie; Yang, Lu; Zou, Ling; Xiang, Junyu; Dong, Shiwu; Yang, Xiaochao

2017-04-01

Cerium oxide nanoparticles (CNPs) have been intensively explored for biomedical applications in recent few years due to the versatile enzyme mimetic activities of the nanoparticles. However, the control of CNPs quality through the optimization of synthesis conditions remains largely unexplored as most of the previous studies only focus on utilizing the catalytic activities of the nanoparticles. In the present study, CNPs with size about 5 nm were synthesized by thermal decomposition method using traditional convective heating and recently developed microwave irradiation as heating source. The quality of CNPs synthesized by the two heating manner was evaluated. The CNPs synthesized by convective heating were slightly smaller than that synthesized by microwave irradiation heating. The cores of the CNPs synthesized by the two heating manner have similar crystal structure. While the surface subtle structures of the CNPs synthesized by two heating manner were different. The CNPs synthesized by microwave irradiation have more surface reactive hot spot than that synthesized by convective heating as the nanoparticles responded more actively to the redox environment variation. This difference resulted in the higher superoxide dismutase (SOD) mimetic activity of CNPs synthesized by microwave irradiation heating than that of the convective heating. Preliminary experiments indicated that the CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress due to the higher SOD mimetic activity of the nanoparticles.

TRANSP: status and planning

NASA Astrophysics Data System (ADS)

Andre, R.; Carlsson, J.; Gorelenkova, M.; Jardin, S.; Kaye, S.; Poli, F.; Yuan, X.

2016-10-01

TRANSP is an integrated interpretive and predictive transport analysis tool that incorporates state of the art heating/current drive sources and transport models. The treatments and transport solvers are becoming increasingly sophisticated and comprehensive. For instance, the ISOLVER component provides a free boundary equilibrium solution, while the PT- SOLVER transport solver is especially suited for stiff transport models such as TGLF. TRANSP incorporates high fidelity heating and current drive source models, such as NUBEAM for neutral beam injection, the beam tracing code TORBEAM for EC, TORIC for ICRF, the ray tracing TORAY and GENRAY for EC. The implementation of selected components makes efficient use of MPI for speed up of code calculations. Recently the GENRAY-CQL3D solver for modeling of LH heating and current drive has been implemented and currently being extended to multiple antennas, to allow modeling of EAST discharges. Also, GENRAY+CQL3D is being extended to the use of EC/EBW and of HHFW for NSTX-U. This poster will describe present uses of the code worldwide, as well as plans for upgrading the physics modules and code framework. Work supported by the US Department of Energy under DE-AC02-CH0911466.

APT Blanket Thermal Analyses of Top Horizontal Row 1 Modules

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

Shadday, M.A.

1999-09-20

The Accelerator Production of Tritium (APT) cavity flood system (CFS) is designed to be the primary safeguard for the integrity of the blanket modules during loss of coolant accidents (LOCAs). For certain large break LOCAs the CFS also provides backup for the residual heat removal systems (RHRs) in cooling the target assemblies. In the unlikely event that the internal flow passages in a blanket module or target assembly dryout, decay heat in the metal structures will be dissipated to the CFS through the module or assembly walls (i.e., rung outer walls). The target assemblies consist of tungsten targets encased inmore » steel conduits, and they can safely sustain high metal temperatures. Under internally dry conditions, the cavity flood fluid will cool the target assemblies with vigorous nucleate boiling on the external surfaces. However, the metal structures in the blanket modules consist of lead cladded in aluminum, and they have a long-term exposure temperature limit currently set to 150 degrees C. Simultaneous LOCAs in both the target and blanket heat removal systems (HRS) could result in dryout of the target ladders, as well as the horizontal blanket modules above the target. The cavity flood coolant would boil on the outside surfaces of the target ladder rungs, and the resultant steam could reduce the effectiveness of convection heat transfer from the blanket modules to the cavity flood coolant. A two-part analysis was conducted to ascertain if the cavity flood system can adequately cool the blanket modules above the targets, even when boiling is occurring on the outer surfaces of the target ladder rungs. The first part of the analysis was to model transient thermal conduction in the front top horizontal row 1 module (i.e. top horizontal modules nearest the incoming beam), while varying parametrically the convection heat transfer coefficient (htc) for the external surfaces exposed to the cavity flood flow. This part of the analysis demonstrated that the module could adequately conduct heat to the outer module surfaces, given reasonable values for the convection heat transfer coefficients. The second part of the analysis consisted of two-phase flow modeling of the natural circulation of the cavity flood fluid past the top modules. Slots in the top shield allow the cavity flood fluid to circulate. The required width for these slots, to prevent steam from backing up and blanketing the outer surfaces of the top modules, was determined.« less

Light-intensity modulator withstands high heat fluxes

NASA Technical Reports Server (NTRS)

Maples, H. G.; Strass, H. K.

1966-01-01

Mechanism modulates and controls the intensity of luminous radiation in light beams associated with high-intensity heat flux. This modulator incorporates two fluid-cooled, externally grooved, contracting metal cylinders which when rotated about their longitudinal axes present a circular aperture of varying size depending on the degree of rotation.

Membrane module assembly

DOEpatents

Kaschemekat, J.

1994-03-15

A membrane module assembly is described which is adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation. 2 figures.

Sodium Based Heat Pipe Modules for Space Reactor Concepts: Stainless Steel SAFE-100 Core

NASA Technical Reports Server (NTRS)

Martin, James J.; Reid, Robert S.

2004-01-01

A heat pipe cooled reactor is one of several candidate reactor cores being considered for advanced space power and propulsion systems to support future space exploration applications. Long life heat pipe modules, with designs verified through a combination of theoretical analysis and experimental lifetime evaluations, would be necessary to establish the viability of any of these candidates, including the heat pipe reactor option. A hardware-based program was initiated to establish the infrastructure necessary to build heat pipe modules. This effort, initiated by Los Alamos National Laboratory and referred to as the Safe Affordable Fission Engine (SAFE) project, set out to fabricate and perform non-nuclear testing on a modular heat pipe reactor prototype that can provide 100 kilowatt from the core to an energy conversion system at 700 C. Prototypic heat pipe hardware was designed, fabricated, filled, closed-out and acceptance tested.

All-optical, thermo-optical path length modulation based on the vanadium-doped fibers.

PubMed

Matjasec, Ziga; Campelj, Stanislav; Donlagic, Denis

2013-05-20

This paper presents an all-fiber, fully-optically controlled, optical-path length modulator based on highly absorbing optical fiber. The modulator utilizes a high-power 980 nm pump diode and a short section of vanadium-co-doped single mode fiber that is heated through absorption and a non-radiative relaxation process. The achievable path length modulation range primarily depends on the pump's power and the convective heat-transfer coefficient of the surrounding gas, while the time response primarily depends on the heated fiber's diameter. An absolute optical length change in excess of 500 µm and a time-constant as short as 11 ms, were demonstrated experimentally. The all-fiber design allows for an electrically-passive and remote operation of the modulator. The presented modulator could find use within various fiber-optics systems that require optical (remote) path length control or modulation.

Acoustic signal recovery by thermal demodulation

NASA Astrophysics Data System (ADS)

Boullosa, R. R.; Santillán, Arturo O.

2006-10-01

One operating mode of recently developed thermoacoustic transducers is as an audio speaker that uses an input superimposed on a direct current; as a result, the audio signal occurs at the same frequency as the input signal. To extend the potential applications of these kinds of sources, the authors propose an alternative driving mode in which a simple thermoacoustic device, consisting of a metal film over a substrate and a heat sink, is excited with a high frequency sinusoid that is amplitude modulated by a lower frequency signal. They show that the modulating signal is recovered in the radiated waves due to a mechanism that is inherent to this type of thermoacoustic process. If the frequency of the carrier is higher than 30kHz and any modulating signal (the one of interest) is in the audio frequency range, only this signal will be heard. Thus, the thermoacoustic device operates as an audio-band, self-demodulating speaker.

Thermal management and light extraction in multi-chip and high-voltage LEDs by cup-shaped copper heat spreader technology

NASA Astrophysics Data System (ADS)

Horng, Ray-Hua; Hu, Hung-Lieh; Tang, Li-Shen; Ou, Sin-Liang

2013-03-01

For LEDs with original structure and copper heat spreader, the highest surface temperatures of 3×3 array LEDs modules were 52.6 and 42.67 °C (with 1050 mA injection current), while the highest surface temperatures of 4×4 array LEDs modules were 58.55 and 48.85 °C (with 1400 mA injection current), respectively. As the 5×5 array LEDs modules with original structure and copper heat spreader were fabricated, the highest surface temperatures at 1750 mA injection current were 68.51 and 56.73 °C, respectively. The thermal resistance of optimal LEDs array module with copper heat spreader on heat sink using compound solder is reduced obviously. On the other hand, the output powers of 3×3, 4×4 and 5×5 array LEDs modules with original structure were 3621.7, 6346.3 and 9760.4 mW at injection currents of 1050, 1400 and 1750 mA, respectively. Meanwhile, the output powers of these samples with copper heat spreader can be improved to 4098.5, 7150.3 and 10919.6 mW, respectively. The optical and thermal characteristics of array LEDs module have been improved significantly using the cup-shaped copper structure. Furthermore, various types of epoxy-packaged LEDs with cup-shaped structure were also fabricated. It is found that the light extraction efficiency of LED with semicircle package has 55% improvement as compared to that of LED with flat package. The cup-shaped copper structure was contacted directly with sapphire to enhance heat dissipation. In addition to efficient heat dissipation, the light extraction of the lateral emitting in high-power LEDs can be improved.

Effect of inert cover gas on performance of radioisotope Stirling space power system

NASA Astrophysics Data System (ADS)

Carpenter, R.; Kumar, V.; Or, C.; Schock, A.

2001-02-01

This paper describes an updated Orbital design of a radioisotope Stirling power system and its predicted performance at the beginning and end of a six-year mission to the Jovian moon Europa. The design is based on General Purpose Heat Source (GPHS) modules identical to those previously developed and safety-qualified by the Department of Energy (DOE) which were successfully launched on missions to Jupiter and Saturn by the Jet Propulsion Laboratory (JPL). In each generator, the heat produced by the decay of the Pu-238 isotope is converted to electric power by two free-piston Stirling engines and linear alternators developed by Stirling Technology Company (STC), and their rejected waste heat is transported to radiators by heat pipes. The principal difference between the proposed system design and previous Orbital designs (Or et al., 2000) is the thermal insulation between the heat source and the generator's housing. Previous designs had employed multifoil insulation, whereas the design described here employs Min-K-1800 thermal insulation. Such insulation had been successfully used by Teledyne and GE in earlier RTGs (Radioisotope Thermoelectric Generators). Although Min-K is a much poorer insulator than multifoil in vacuum and requires a substantially greater thickness for equivalent performance, it offers compensating advantages. Specifically it makes it possible to adjust the generator's BOM temperatures by filling its interior volume with inert cover gas. This makes it possible to meet the generator's BOM and EOM performance goals without exceeding its allowable temperature at the beginning of the mission. .

An On-Site Thermoelectric Cooling Device for Cryotherapy and Control of Skin Blood Flow

PubMed Central

Mejia, Natalia; Dedow, Karl; Nguy, Lindsey; Sullivan, Patrick; Khoshnevis, Sepideh; Diller, Kenneth R.

2015-01-01

Cryotherapy involves the surface application of low temperatures to enhance the healing of soft tissue injuries. Typical devices embody a remote source of chilled water that is pumped through a circulation bladder placed on the treatment site. In contrast, the present device uses thermoelectric refrigeration modules to bring the cooling source directly to the tissue to be treated, thereby achieving significant improvements in control of therapeutic temperature while having a reduced size and weight. A prototype system was applied to test an oscillating cooling and heating protocol for efficacy in regulating skin blood perfusion in the treatment area. Data on 12 human subjects indicate that thermoelectric coolers (TECs) delivered significant and sustainable changes in perfusion for both heating (increase by (±SE) 173.0 ± 66.0%, P < 0.005) and cooling (decrease by (±SE) 57.7 ± 4.2%, P < 0.0005), thus supporting the feasibility of a TEC-based device for cryotherapy with local temperature regulation. PMID:26421089

An On-Site Thermoelectric Cooling Device for Cryotherapy and Control of Skin Blood Flow.

PubMed

Mejia, Natalia; Dedow, Karl; Nguy, Lindsey; Sullivan, Patrick; Khoshnevis, Sepideh; Diller, Kenneth R

2015-12-01

Cryotherapy involves the surface application of low temperatures to enhance the healing of soft tissue injuries. Typical devices embody a remote source of chilled water that is pumped through a circulation bladder placed on the treatment site. In contrast, the present device uses thermoelectric refrigeration modules to bring the cooling source directly to the tissue to be treated, thereby achieving significant improvements in control of therapeutic temperature while having a reduced size and weight. A prototype system was applied to test an oscillating cooling and heating protocol for efficacy in regulating skin blood perfusion in the treatment area. Data on 12 human subjects indicate that thermoelectric coolers (TECs) delivered significant and sustainable changes in perfusion for both heating (increase by (±SE) 173.0 ± 66.0%, P < 0.005) and cooling (decrease by (±SE) 57.7 ± 4.2%, P < 0.0005), thus supporting the feasibility of a TEC-based device for cryotherapy with local temperature regulation.

Initial observations of cavitation-induced erosion of liquid metal spallation target vessels at the Spallation Neutron Source

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

McClintock, David A; Riemer, Bernie; Ferguson, Phillip D

2012-01-01

During operation of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory the mechanical properties of the AISI 316L target module are altered by high-energy neutron and proton radiation. The interior surfaces of the target vessel are also damaged by cavitation-induced erosion, which results from repetitive rapid heating of the liquid mercury by high-energy proton beam pulses. Until recently no observations of cavitation-induced erosion were possible for conditions prototypical to the SNS. Post irradiation examination (PIE) of the first and second operational SNS targets was performed to gain insight into the radiation-induced changes in mechanical properties of the 316Lmore » target material and the extent of cavitation-induced erosion to the target vessel inner surfaces. Observations of cavitation-induced erosion of the first and second operational SNS target modules are presented here, including images of the target vessel interiors and specimens removed from the target beam-entrance regions.« less

Fabrication of Bi–Sb–Te Thermoelectric by Cold-Pressed Sintering for Motorcycle Exhaust.

PubMed

Kao, Mu-Jung; Chen, Ming-Jing

2017-04-01

This study was conducted on the Bi–Sb–Te thermoelectric material which is cold-pressed Sintering under 750 Mpa to make square thermoelectric pairs with size 8.2 mm × 8.2 mm and thicknesses 0.8 mm and 1.5 mm. The zone melting method was used to acquire P-type thermoelectric material Bi0.4Sb1.6Te3 and N-type thermoelectric material Bi2Te2.5Se0.5. At temperature 383 K, the measured Seebeck coefficient of Bi0.4Sb1.6Te3 is 222 μV/K, and its thermoelectric figure of merit ZT is 1.35. At temperature 400 K, the measured Seebeck coefficient of Bi2Te2.5Se0.5 is 210 μV/K, and its thermoelectric figure of merit ZT is 1.13. Using Solder paste Sn42Bi58 and copper electrode plate are in series connection with 16 pieces of P/N thermoelectric material to form thermoelectric modules. The thermoelectric module is actually pasted on the motorcycle waste heat source to be evaluated the performance, making the cold-end temperature dissipation heat can enhance the temperature difference between it so as to increase the output power. Increasing the leg thickness of thermoelectric module and making the about 35 °C temperature-difference of those can obviously enhance the performance of in terms of its voltage, its thermoelectric figure of merit ZT and output power of the thermoelectric modules.

[Analysis of gene expression pattern in peripheral blood leukocytes during experimental heat wave].

PubMed

Feoktistova, E S; Skamrov, A V; Goryunova, L E; Khaspekov, G L; Osyaeva, M K; Rodnenkov, O V; Beabealashvilli, R Sh

2017-03-01

The conditions of Moscow 2010 summer heat wave were simulated in an accommodation module. Six healthy men aged from 22 to 46 years stayed in the module for 30 days. Measurements of gene expression in peripheral blood leukocytes before, during and 3 day after simulated heat wave were performed using qRT-PCR. We observed a shift in the expression level of certain genes after heat exposure for a long time, and rapid return to the initial level, when volunteers leaved the accommodation module. Eight genes were chosen to form the "heat expression signature". EGR2, EGR3 were upregulated in all six volunteers, EGR1, SIRT1, CYP51A1, MAPK9, BAG5, MNDA were upregulated in 5 volunteers.

Latent Heating from TRMM Satellite Measurements

NASA Technical Reports Server (NTRS)

Tao, W.-K.; Smith, E.; Olson, W.

2005-01-01

Rainfall production is a fundamental process within the Earth;s hydrological cycle because it represents both a principal forcing term in surface water budgets, and its energetics corollary, latent heating, is the principal source of atmospheric diabatic heating. Latent heat release itself is a consequence of phase changes between the vapor, liquid, and frozen states of water. The properties of the vertical distribution of latent heat release modulate large-scale meridional and zonal circulations with the Tropics - as well as modify the energetic efficiencies of mid-latitude weather systems. This paper highlights the retrieval of observatory, which was launched in November 1997 as a joint American-Japanese space endeavor. Since then, TRMM measurements have been providing an accurate four-dimensional amount of rainfall over the global Tropics and sub-tropics - information which can be used to estimate the spacetime structure of latent heating across the Earth's low latitudes. A set of algorithm methodologies has and continues to be developed to estimate latent heating based on rain rate profile retrievals obtained from TRMM measurements. These algorithms are briefly described followed by a discussion of the foremost latent heating products that can be generate from them. The investigation then provides an overview of how TRMM-derived latent heating information is currently being used in conjunction with global weather and climate models, concluding with remarks intended to stimulate further research on latent heating retrieval from satellites.

Multi-megawatt millimeter-wave source for plasma heating and control

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

Hirshfield, J.L.; Wang, C.; Ganguly, A.K.

1995-12-31

Results of a feasibility study are summarized for multi-megawatt mm-wavelength gyroharmonic converters for plasma heating applications. Output power in these devices is extracted at a high harmonic of the modulation frequency of a spatiotemporally gyrating electron beam prepared using cyclotron autoresonance acceleration. An example is described in which an output of 2.2 MW at 148.5 GHz is predicted at the 13th harmonic of an 8 MW 11.424 GHz CARA, after including waveguide ohmic wall losses. Achievement of this performance requires a high quality 200 kV, 16 A luminar pencil beam injected into CARA, and effective suppression of competing output modes;more » means to realize these requirements are discussed.« less

An electronic cryoprobe for cryosurgery using heat pipes and thermoelectric coolers: a preliminary report.

PubMed

Hamilton, A; Hu, J

1993-01-01

A hand-held fully electrically powered and programmable cryoprobe for general-purpose cryosurgery and cryotherapy has been developed. By combining the technologies of thermoelectric cooling and heat pipes, the temperature at the tip of the probe can easily reach -50 to -60 degrees C. It can hold below -40 degrees C when it cools a load of 10 W at the tip. Previous efforts developing cryoprobes made of thermoelectric modules have been hindered by the inherent characteristics of commercially available thermoelectric coolers: low efficiency, size and inflexible shape and very sensitive to heat intensity and thermal insulation. Matching thermoelectrics with heat pipes uses the advantages of both technologies. In the cryoprobe the heat pipe is used to focus and transport the cooling power of multi-thermoelectric modules. The heat flux for the thermoelectric modules is reduced and their efficiencies are increased. The transport of heat by a heat pipe also allows flexible access to treated spots of patients.

In-Band and Out-of-Band VLF Scattering by Modulated D-region Heating at the Arecibo Observatory

NASA Astrophysics Data System (ADS)

Burch, H.; Moore, R. C.

2017-12-01

The HF heating facility at the Arecibo Observatory is able to create an artificial disturbance in the D-region ionosphere through HF heating, a phenomenon which has been well documented at HAARP. Very Low Frequency (VLF, 3-30 kHz) waves radiated by Navy transmitters propagate around the globe in the Earth-Ionosphere waveguide and scatter from this artificially disturbed region. We investigated this effect at the Arecibo Observatory during the July 2017 HF heating campaign using an amplitude-modulated HF signal at modulation frequencies from below 1 Hz to approximately 5 kHz. VLF receivers stationed in Puerto Rico measured the amplitude and phase of propagating VLF transmitter signals under HF-heated and ambient ionospheric conditions. We interpret the scattered VLF signals in the context of an ionospheric HF heating model that has been successfully used to interpret the results of HAARP experiments for a number of years. We present initial results regarding the generation and detection of nonlinear mixing components at the VLF transmitter frequency +/- the HF modulation frequency.

Multiple Restart Testing of a Stainless Steel Sodium Heat Pipe Module

NASA Astrophysics Data System (ADS)

Martin, James; Mireles, Omar; Reid, Robert

2005-02-01

A heat pipe cooled reactor is one of several candidate reactor concepts being considered for space power and propulsion systems to support future space exploration activities. Long life heat pipe modules, with concepts verified through a combination of theoretical analysis and experimental evaluations, would be necessary to establish the viability of this option. A number of stainless steel/sodium heat pipe modules have been designed and fabricated to support experimental testing of a Safe Affordable Fission Engine (SAFE) project, a 100-kWt core design pursued jointly by the Marshall Space Flight Center and the Los Alamos National Laboratory. One of the SAFE heat pipe modules was successfully subjected to over 200 restarts, examining the behavior of multiple passive freeze/thaw operations. Typical operation included a 1-hour startup to an average evaporator temperature of 1000 K followed by a 15-minute hold at temperature. Nominal maximum input power to the evaporator (measured at the power supply) during the hold period was 1.9 kW, with approximately 1.6 kW calculated as the axial power transfer to the condenser (the 300W difference was lost to environment at the evaporator surface). Between heating cycles the module was cooled to less than 325 K, returning the sodium to a frozen state in preparation for the next startup cycle.

Multiple Restart Testing of a Stainless Steel Sodium Heat Pipe Module

NASA Technical Reports Server (NTRS)

Martin, James; Mireles, Omar; Reid, Robert

2005-01-01

A heat pipe cooled reactor is one of several candidate reactor cores being considered for space power and propulsion systems to support future space exploration activities. Long life heat pipe modules. with designs verified through a combination of theoretical analysis and experimental evaluations. would be necessary to establish the viability of this option. A hardware-based program was initiated to begin experimental testing of components to verify compliance of proposed designs. To this end, a number of stainless steel/sodium heat pipe modules have been designed and fabricated to support experimental testing of a Safe Affordable Fission Engine (SAFE) project, a 100-kWt core design pursued jointly by the Marshall Space Flight Center and the Los Alamos National Laboratory. One of the SAFE heat pipe modules was successfully subjected to over 200 restarts. examining the behavior of multiple passive freeze/thaw operations. Typical operation included a 1-hour startup to an average evaporator temperature of 1000 K followed by a 15 minute hold at temperature. Nominal maximum input power during the hold period was 1.9 kW. Between heating cycles the module was cooled to less than 325 K, returning the sodium to a frozen state in preparation fop the next startup cycle.

Engineering evaluation of a sodium hydroxide thermal energy storage module

NASA Technical Reports Server (NTRS)

Perdue, D. G.; Gordon, L. H.

1980-01-01

An engineering evaluation of thermal energy storage prototypes was performed in order to assess the development status of latent heat storage media. The testing and the evaluation of a prototype sodium hydroxide module is described. This module stored off-peak electrical energy as heat for later conversion to domestic hot water needs.

Students' Design of Experiments: An Inquiry Module on the Conduction of Heat

ERIC Educational Resources Information Center

Hatzikraniotis, E.; Kallery, M.; Molohidis, A.; Psillos, D.

2010-01-01

This article examines secondary students' design of experiments after engagement in an innovative and inquiry-oriented module on heat transfer. The module consists of an integration of hands-on experiments, simulated experiments and microscopic model simulations, includes a structured series of guided investigative tasks and was implemented for a…

Experimental Validation of Source Temperature Modulation Via a Thermal Switch in Thermal Energy Harvesting (Preprint)

DTIC Science & Technology

2007-12-01

International Journal of Exergy , Vol. 2, No. 2, 2005, pp. 120-145. 8Hoyos, G.E., Rao, K.R., and Jerger, D., “Fast Transient Response of Novel...DATES COVERED (From - To) December 2007 Journal Article Preprint 31 July 2005 – 31 July 2007 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 4...distribution unlimited. 13. SUPPLEMENTARY NOTES Journal article submitted to the Journal of Thermophysics and Heat Transfer. The U.S. Government is joint

Method and apparatus for active control of combustion rate through modulation of heat transfer from the combustion chamber wall

DOEpatents

Roberts, Jr., Charles E.; Chadwell, Christopher J.

2004-09-21

The flame propagation rate resulting from a combustion event in the combustion chamber of an internal combustion engine is controlled by modulation of the heat transfer from the combustion flame to the combustion chamber walls. In one embodiment, heat transfer from the combustion flame to the combustion chamber walls is mechanically modulated by a movable member that is inserted into, or withdrawn from, the combustion chamber thereby changing the shape of the combustion chamber and the combustion chamber wall surface area. In another embodiment, heat transfer from the combustion flame to the combustion chamber walls is modulated by cooling the surface of a portion of the combustion chamber wall that is in close proximity to the area of the combustion chamber where flame speed control is desired.

Experimental Study of Thermal Energy Storage Characteristics using Heat Pipe with Nano-Enhanced Phase Change Materials

NASA Astrophysics Data System (ADS)

Krishna, Jogi; Kishore, P. S.; Brusly Solomon, A.

2017-08-01

The paper presents experimental investigations to evaluate thermal performance of heat pipe using Nano Enhanced Phase Change Material (NEPCM) as an energy storage material (ESM) for electronic cooling applications. Water, Tricosane and nano enhanced Tricosane are used as energy storage materials, operating at different heating powers (13W, 18W and 23W) and fan speeds (3.4V and 5V) in the PCM cooling module. Three different volume percentages (0.5%, 1% and 2%) of Nano particles (Al2O3) are mixed with Tricosane which is the primary PCM. This experiment is conducted to study the temperature distributions of evaporator, condenser and PCM during the heating as well as cooling. The cooling module with heat pipe and nano enhanced Tricosane as energy storage material found to save higher fan power consumption compared to the cooling module that utilities only a heat pipe.

Computational and theoretical investigation of Mars's atmospheric impact on the descent module "Exomars-2018" under aerodynamic deceleration

NASA Astrophysics Data System (ADS)

Golomazov, M. M.; Ivankov, A. A.

2016-12-01

Methods for calculating the aerodynamic impact of the Martian atmosphere on the descent module "Exomars-2018" intended for solving the problem of heat protection of the descent module during aerodynamic deceleration are presented. The results of the investigation are also given. The flow field and radiative and convective heat exchange are calculated along the trajectory of the descent module until parachute system activation.

Pattern-free thermal modulator via thermal radiation between Van der Waals materials

NASA Astrophysics Data System (ADS)

Liu, Xianglei; Shen, Jiadong; Xuan, Yimin

2017-10-01

Modulating heat flux provides a platform for a plethora of emerging devices such as thermal diodes, thermal transistors, and thermal memories. Here, a pattern-free noncontact thermal modulator is proposed based on the mechanical rotation between two Van der Waals films with optical axes parallel to the surfaces. A modulation contrast can reach a value higher than 5 for hexagonal Boron Nitride (hBN) films separated by a nanoscale gap distance. The dominant radiative heat exchange comes from the excitation of both Type I and Type II hyperbolic surface phonon polaritons (HSPhPs) at the vacuum-hBN interface for different orientations, while the large modulation contrast is mainly attributed to the mismatching Type I HSPhPs induced by rotation. This work opens the possibility to design cheap thermal modulators without relying on nanofabrication techniques, and paves the way to apply natural Van der Waals materials in manipulating heat currents in an active way.

SPACECRAFT (S/C)-012 - COMMAND MODULE (CM) - HEAT SHIELD INSTALLATION

NASA Image and Video Library

1966-04-18

S66-41851 (1966) --- High angle view of Spacecraft 012 Command Module, looking toward -Z axis, during preparation for installation of the crew compartment heat shield, showing mechanics working on aft bay.

An approach to design a 90Sr radioisotope thermoelectric generator using analytical and Monte Carlo methods with ANSYS, COMSOL, and MCNP.

PubMed

Khajepour, Abolhasan; Rahmani, Faezeh

2017-01-01

In this study, a 90 Sr radioisotope thermoelectric generator (RTG) with power of milliWatt was designed to operate in the determined temperature (300-312K). For this purpose, the combination of analytical and Monte Carlo methods with ANSYS and COMSOL software as well as the MCNP code was used. This designed RTG contains 90 Sr as a radioisotope heat source (RHS) and 127 coupled thermoelectric modules (TEMs) based on bismuth telluride. Kapton (2.45mm in thickness) and Cryotherm sheets (0.78mm in thickness) were selected as the thermal insulators of the RHS, as well as a stainless steel container was used as a generator chamber. The initial design of the RHS geometry was performed according to the amount of radioactive material (strontium titanate) as well as the heat transfer calculations and mechanical strength considerations. According to the Monte Carlo simulation performed by the MCNP code, approximately 0.35 kCi of 90 Sr is sufficient to generate heat power in the RHS. To determine the optimal design of the RTG, the distribution of temperature as well as the dissipated heat and input power to the module were calculated in different parts of the generator using the ANSYS software. Output voltage according to temperature distribution on TEM was calculated using COMSOL. Optimization of the dimension of the RHS and heat insulator was performed to adapt the average temperature of the hot plate of TEM to the determined hot temperature value. This designed RTG generates 8mW in power with an efficiency of 1%. This proposed approach of combination method can be used for the precise design of various types of RTGs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nonlinear convective flows in a two-layer system under the action of spatial temperature modulation of heat release/consumption at the interface

NASA Astrophysics Data System (ADS)

Simanovskii, Ilya B.; Viviani, Antonio; Dubois, Frank

2018-06-01

An influence of a spatial temperature modulation of the interfacial heat release/consumption on nonlinear convective flows in the 47v2 silicone oil - water system, is studied. Rigid heat-insulated lateral walls, corresponding to the case of closed cavities, have been considered. Transitions between the flows with different spatial structures, have been investigated. It is shown that the spatial modulation can change the sequence of bifurcations and lead to the appearance of specific steady and oscillatory flows in the system.

A Radiation Transfer Solver for Athena Using Short Characteristics

NASA Astrophysics Data System (ADS)

Davis, Shane W.; Stone, James M.; Jiang, Yan-Fei

2012-03-01

We describe the implementation of a module for the Athena magnetohydrodynamics (MHD) code that solves the time-independent, multi-frequency radiative transfer (RT) equation on multidimensional Cartesian simulation domains, including scattering and non-local thermodynamic equilibrium (LTE) effects. The module is based on well known and well tested algorithms developed for modeling stellar atmospheres, including the method of short characteristics to solve the RT equation, accelerated Lambda iteration to handle scattering and non-LTE effects, and parallelization via domain decomposition. The module serves several purposes: it can be used to generate spectra and images, to compute a variable Eddington tensor (VET) for full radiation MHD simulations, and to calculate the heating and cooling source terms in the MHD equations in flows where radiation pressure is small compared with gas pressure. For the latter case, the module is combined with the standard MHD integrators using operator splitting: we describe this approach in detail, including a new constraint on the time step for stability due to radiation diffusion modes. Implementation of the VET method for radiation pressure dominated flows is described in a companion paper. We present results from a suite of test problems for both the RT solver itself and for dynamical problems that include radiative heating and cooling. These tests demonstrate that the radiative transfer solution is accurate and confirm that the operator split method is stable, convergent, and efficient for problems of interest. We demonstrate there is no need to adopt ad hoc assumptions of questionable accuracy to solve RT problems in concert with MHD: the computational cost for our general-purpose module for simple (e.g., LTE gray) problems can be comparable to or less than a single time step of Athena's MHD integrators, and only few times more expensive than that for more general (non-LTE) problems.

Status of the ion sources developments for the Spiral2 project at GANILa)

NASA Astrophysics Data System (ADS)

Lehérissier, P.; Bajeat, O.; Barué, C.; Canet, C.; Dubois, M.; Dupuis, M.; Flambard, J. L.; Frigot, R.; Jardin, P.; Leboucher, C.; Lemagnen, F.; Maunoury, L.; Osmond, B.; Pacquet, J. Y.; Pichard, A.; Thuillier, T.; Peaucelle, C.

2012-02-01

The SPIRAL 2 facility is now under construction and will deliver either stable or radioactive ion beams. First tests of nickel beam production have been performed at GANIL with a new version of the large capacity oven, and a calcium beam has been produced on the heavy ion low energy beam transport line of SPIRAL 2, installed at LPSC Grenoble. For the production of radioactive beams, several target/ion-source systems (TISSs) are under development at GANIL as the 2.45 GHz electron cyclotron resonance ion source, the surface ionization source, and the oven prototype for heating the uranium carbide target up to 2000 °C. The existing test bench has been upgraded for these developments and a new one, dedicated for the validation of the TISS before mounting in the production module, is under design. Results and current status of these activities are presented.

A Thermoelectric Energy Harvesting System for Powering Wireless Sensors in Nuclear Power Plants

NASA Astrophysics Data System (ADS)

Chen, Jie; Klein, Jackson; Wu, Yongjia; Xing, Shaoxu; Flammang, Robert; Heibel, Michael; Zuo, Lei

2016-10-01

Safety is the most important issue in the development of nuclear energy. This paper reports experimental studies of a thermoelectric energy harvesting system designed for integration in a nuclear power plant capable of performing in radiation rich environments and producing enough power to run wireless sensors meant to increase plant safety. Furthermore, the system, which utilizes wasted heat present in coolant system piping, has the unique ability to provide power in both normal and accidental situations, to run the sensors without the need for external power. Two energy harvesting prototypes were designed utilizing a heat pipe for heat transfer. The first can supply a maximum power of 2.25 W using two Bi2Te3 thermoelectric modules of 2.79cm (1.1") × 2.79 cm (1.1”), in a source temperature near 250 °C. A second design was put forward to extend the application in higher-temperature primary loops, in which one PbTe-Bi2Te3 hybrid TEG module of 5.6cm (2.2") × 5.6 cm (2.2") can provide a power of 3.0 W when the hot side temperature reaches 340 °C. In addition to the energy harvester, wireless communication circuits were developed along with an integrated power management circuit for wireless data transmission. A high intensity gamma radiation experiment was conducted during which each component was irradiated. A total dose of 200 kGy±10% (20M rads) was applied to the first prototype in order to approximate the expected lifetime accumulation for one implemented thermoelectric generator. Results showed that thermoelectric modules used in the prototype had no reduction in voltage output throughout irradiation. Throughout the experiment the harvester system witnessed a small voltage drop in open circuit voltage attributed to a reduction in heat pipe performance from radiation exposure. We also acquired a baseline radiation survivability level for non-hardened, non-shielded electronics of 102 Gy.

Modular Stirling Radioisotope Generator

NASA Technical Reports Server (NTRS)

Schmitz, Paul C.; Mason, Lee S.; Schifer, Nicholas A.

2016-01-01

High-efficiency radioisotope power generators will play an important role in future NASA space exploration missions. Stirling Radioisotope Generators (SRGs) have been identified as a candidate generator technology capable of providing mission designers with an efficient, high-specific-power electrical generator. SRGs high conversion efficiency has the potential to extend the limited Pu-238 supply when compared with current Radioisotope Thermoelectric Generators (RTGs). Due to budgetary constraints, the Advanced Stirling Radioisotope Generator (ASRG) was canceled in the fall of 2013. Over the past year a joint study by NASA and the Department of Energy (DOE) called the Nuclear Power Assessment Study (NPAS) recommended that Stirling technologies continue to be explored. During the mission studies of the NPAS, spare SRGs were sometimes required to meet mission power system reliability requirements. This led to an additional mass penalty and increased isotope consumption levied on certain SRG-based missions. In an attempt to remove the spare power system, a new generator architecture is considered, which could increase the reliability of a Stirling generator and provide a more fault-tolerant power system. This new generator called the Modular Stirling Radioisotope Generator (MSRG) employs multiple parallel Stirling convertor/controller strings, all of which share the heat from the General Purpose Heat Source (GPHS) modules. For this design, generators utilizing one to eight GPHS modules were analyzed, which provided about 50 to 450 W of direct current (DC) to the spacecraft, respectively. Four Stirling convertors are arranged around each GPHS module resulting in from 4 to 32 Stirling/controller strings. The convertors are balanced either individually or in pairs, and are radiatively coupled to the GPHS modules. Heat is rejected through the housing/radiator, which is similar in construction to the ASRG. Mass and power analysis for these systems indicate that specific power may be slightly lower than the ASRG and similar to the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). However, the reliability should be significantly increased compared to ASRG.

Modular Stirling Radioisotope Generator

NASA Technical Reports Server (NTRS)

Schmitz, Paul C.; Mason, Lee S.; Schifer, Nicholas A.

2015-01-01

High efficiency radioisotope power generators will play an important role in future NASA space exploration missions. Stirling Radioisotope Generators (SRG) have been identified as a candidate generator technology capable of providing mission designers with an efficient, high specific power electrical generator. SRGs high conversion efficiency has the potential to extend the limited Pu-238 supply when compared with current Radioisotope Thermoelectric Generators (RTG). Due to budgetary constraints, the Advanced Stirling Radioisotope Generator (ASRG) was canceled in the fall of 2013. Over the past year a joint study by NASA and DOE called the Nuclear Power Assessment Study (NPAS) recommended that Stirling technologies continue to be explored. During the mission studies of the NPAS, spare SRGs were sometimes required to meet mission power system reliability requirements. This led to an additional mass penalty and increased isotope consumption levied on certain SRG-based missions. In an attempt to remove the spare power system, a new generator architecture is considered which could increase the reliability of a Stirling generator and provide a more fault-tolerant power system. This new generator called the Modular Stirling Radioisotope Generator (MSRG) employs multiple parallel Stirling convertor/controller strings, all of which share the heat from the General Purpose Heat Source (GPHS) modules. For this design, generators utilizing one to eight GPHS modules were analyzed, which provide about 50 to 450 watts DC to the spacecraft, respectively. Four Stirling convertors are arranged around each GPHS module resulting in from 4 to 32 Stirling/controller strings. The convertors are balanced either individually or in pairs, and are radiatively coupled to the GPHS modules. Heat is rejected through the housing/radiator which is similar in construction to the ASRG. Mass and power analysis for these systems indicate that specific power may be slightly lower than the ASRG and similar to the MMRTG. However, the reliability should be significantly increased compared to ASRG.

Microtube strip heat exchanger

NASA Astrophysics Data System (ADS)

Doty, F. D.

1991-07-01

During the last quarter, Doty Scientific, Inc. (DSI) continued to make progress on the microtube strip (MTS) heat exchanger. The DSI completed a heat exchanger stress analysis of the ten-module heat exchanger bank; and performed a shell-side flow inhomogeneity analysis of the three-module heat exchanger bank. The company produced 50 tubestrips using an in-house CNC milling machine and began pressing them onto tube arrays. The DSI revised some of the tooling required to encapsulate a tube array and press tubestrips into the array to improve some of the prototype tooling.

Photovoltaic module bypass diode encapsulation

NASA Technical Reports Server (NTRS)

Shepard, N. J., Jr.

1983-01-01

The design and processing techniques necessary to incorporate bypass diodes within the module encapsulant are presented. The Semicon PN junction diode cells were selected. Diode junction to heat spreader thermal resistance measurements, performed on a variety of mounted diode chip types and sizes, have yielded values which are consistently below 1 deg C per watt, but show some instability when thermally cycled over the temperature range from -40 to 150 deg C. Three representative experimental modules, each incorporating integral bypass diode/heat spreader assemblies of various sizes, were designed. Thermal testing of these modules enabled the formulation of a recommended heat spreader plate sizing relationship. The production cost of three encapsulated bypass diode/heat spreader assemblies were compared with similarly rated externally mounted packaged diodes. It is concluded that, when proper designed and installed, these bypass diode devices will improve the overall reliability of a terrestrial array over a 20 year design lifetime.

Stability Analysis and Internal Heating Effect on Oscillatory Convection in a Viscoelastic Fluid Saturated Porous Medium Under Gravity Modulation

NASA Astrophysics Data System (ADS)

Bhadauria, B. S.; Singh, M. K.; Singh, A.; Singh, B. K.; Kiran, P.

2016-12-01

In this paper, we investigate the combined effect of internal heating and time periodic gravity modulation in a viscoelastic fluid saturated porous medium by reducing the problem into a complex non-autonomous Ginzgburg-Landau equation. Weak nonlinear stability analysis has been performed by using power series expansion in terms of the amplitude of gravity modulation, which is assumed to be small. The Nusselt number is obtained in terms of the amplitude for oscillatory mode of convection. The influence of viscoelastic parameters on heat transfer has been discussed. Gravity modulation is found to have a destabilizing effect at low frequencies and a stabilizing effect at high frequencies. Finally, it is found that overstability advances the onset of convection, more with internal heating. The conditions for which the complex Ginzgburg-Landau equation undergoes Hopf bifurcation and the amplitude equation undergoes supercritical pitchfork bifurcation are studied.

Automated Heat-Flux-Calibration Facility

NASA Technical Reports Server (NTRS)

Liebert, Curt H.; Weikle, Donald H.

1989-01-01

Computer control speeds operation of equipment and processing of measurements. New heat-flux-calibration facility developed at Lewis Research Center. Used for fast-transient heat-transfer testing, durability testing, and calibration of heat-flux gauges. Calibrations performed at constant or transient heat fluxes ranging from 1 to 6 MW/m2 and at temperatures ranging from 80 K to melting temperatures of most materials. Facility developed because there is need to build and calibrate very-small heat-flux gauges for Space Shuttle main engine (SSME).Includes lamp head attached to side of service module, an argon-gas-recirculation module, reflector, heat exchanger, and high-speed positioning system. This type of automated heat-flux calibration facility installed in industrial plants for onsite calibration of heat-flux gauges measuring fluxes of heat in advanced gas-turbine and rocket engines.

Introduction to Heating, Ventilation and Air Conditioning (HVAC). Introduction to Construction Series. Instructor Edition.

ERIC Educational Resources Information Center

Associated General Contractors of America, Washington, DC.

This module on introductory heating, ventilating, and air conditioning (HVAC) is one of a series of modules designed to teach basic skills necessary for entry-level employment in this field. The module contains four instructional units that cover the following topics: (1) HVAC materials; (2) HVAC tools; (3) HVAC layout; and (4) HVAC basic skills.…

Solar thermal power systems point-focusing distributed receiver technology project. Volume 2: Detailed report

NASA Technical Reports Server (NTRS)

1980-01-01

The accomplishments of the Point-Focusing Distributed Receiver Technology Project during fiscal year 1979 are detailed. Present studies involve designs of modular units that collect and concentrate solar energy via highly reflective, parabolic-shaped dishes. The concentrated energy is then converted to heat in a working fluid, such as hot gas. In modules designed to produce heat for industrial applications, a flexible line conveys the heated fluid from the module to a heat transfer network. In modules designed to produce electricity the fluid carries the heat directly to an engine in a power conversion unit located at the focus of the concentrator. The engine is mechanically linked to an electric generator. A Brayton-cycle engine is currently being developed as the most promising electrical energy converter to meet near-future needs.

Non-diffusive ignition of a gaseous reactive mixture following time-resolved, spatially distributed energy deposition

NASA Astrophysics Data System (ADS)

Kassoy, D. R.

2014-01-01

Systematic asymptotic methods are applied to the compressible conservation and state equations for a reactive gas, including transport terms, to develop a rational thermomechanical formulation for the ignition of a chemical reaction following time-resolved, spatially distributed thermal energy addition from an external source into a finite volume of gas. A multi-parameter asymptotic analysis is developed for a wide range of energy deposition levels relative to the initial internal energy in the volume when the heating timescale is short compared to the characteristic acoustic timescale of the volume. Below a quantitatively defined threshold for energy addition, a nearly constant volume heating process occurs, with a small but finite internal gas expansion Mach number. Very little added thermal energy is converted to kinetic energy. The gas expelled from the boundary of the hot, high-pressure spot is the source of mechanical disturbances (acoustic and shock waves) that propagate away into the neighbouring unheated gas. When the energy addition reaches the threshold value, the heating process is fully compressible with a substantial internal gas expansion Mach number, the source of blast waves propagating into the unheated environmental gas. This case corresponds to an extremely large non-dimensional hot-spot temperature and pressure. If the former is sufficiently large, a high activation energy chemical reaction is initiated on the short heating timescale. This phenomenon is in contrast to that for more modest levels of energy addition, where a thermal explosion occurs only after the familiar extended ignition delay period for a classical high activation reaction. Transport effects, modulated by an asymptotically small Knudsen number, are shown to be negligible unless a local gradient in temperature, concentration or velocity is exceptionally large.

Numerical investigation of the thermal and electrical performances for combined solar photovoltaic/thermal (PV/T) modules based on internally extruded fin flow channel

NASA Astrophysics Data System (ADS)

Deng, Y. C.; Li, Q. P.; Wang, G. J.

2017-11-01

A solar photovoltaic/thermal (PV/T) module based on internally extruded fin flow channel was investigated numerically in this paper. First of all, the structures of the thin plate heat exchanger and the PV/T module were presented. Then, a numerical model of the PV/T module considering solar irradiation, fluid flow and heat transfer was developed to analyze the performance of the module. Finally, the steady electrical and thermal efficiencies of the PV/T module at different inlet water temperatures and mass flow rates were achieved. These numerical results supply theory basis for practical application of the PV/T module.

Effect of Inert Cover Gas on Performance of Radioisotope Stirling Space Power System

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

Carpenter, Robert; Kumar, V; Ore, C

2001-01-01

This paper describes an updated Orbital design of a radioisotope Stirling power system and its predicted performance at the beginning and end of a six-year mission to the Jovian moon Europa. The design is based on General Purpose Heat Source (GPHS) modules identical to those previously developed and safety-qualified by the Department of Energy (DOE) which were successfully launched to Jupiter and Saturn by the Jet Propulsion Laboratory (JPL). In each generator, the heat produced by the decay of the Pu-238 isotope is converted to electric power by two free-piston Stirling engines and linear alternators developed by Stirling Technology Companymore » (STC), and their rejected waste heat is transported to radiators by heat pipes. The principal difference between the proposed system design and previous Orbital designs (Or et al. 2000) is the thermal insulation between the heat source and the generator's housing. Previous designs had employed multifoil insulation, whereas the design described here employs Min-K-1800 thermal insulation. Such insulation had been successfully used by Teledyne and GE in earlier RTGs (Radioisotope Thermoelectric Generators). Although Min-K is a much poorer insulator than multifoil in vacuum and requires a substantially greater thickness for equivalent performance, it offers compensating advantages. Specifically it makes it possible to adjust the generator's BOM temperatures by filling its interior volume with inert cover gas. This makes it possible to meet the generator's BOM and EOM performance goals without exceeding its allowable temperature at the beginning of the mission.« less

Hyperthyroidism increases the uncoupled ATPase activity and heat production by the sarcoplasmic reticulum Ca2+-ATPase.

PubMed

Arruda, Ana Paula; Da-Silva, Wagner S; Carvalho, Denise P; De Meis, Leopoldo

2003-11-01

The sarcoplasmic reticulum Ca2+-ATPase is able to modulate the distribution of energy released during ATP hydrolysis, so that a portion of energy is used for Ca2+ transport (coupled ATPase activity) and a portion is converted into heat (uncoupled ATPase activity). In this report it is shown that T4 administration to rabbits promotes an increase in the rates of both the uncoupled ATPase activity and heat production in sarcoplasmic reticulum vesicles, and that the degree of activation varies depending on the muscle type used. In white muscles hyperthyroidism promotes a 0.8-fold increase of the uncoupled ATPase activity and in red muscle a 4-fold increase. The yield of vesicles from hyperthyroid muscles is 3-4-fold larger than that obtained from normal muscles; thus the rate of heat production by the Ca2+-ATPase expressed in terms of g of muscle in hyperthyroidism is increased by a factor of 3.6 in white muscles and 12.0 in red muscles. The data presented suggest that the Ca2+-ATPase uncoupled activity may represent one of the heat sources that contributes to the enhanced thermogenesis noted in hyperthyroidism.

Molecular wires acting as quantum heat ratchets.

PubMed

Zhan, Fei; Li, Nianbei; Kohler, Sigmund; Hänggi, Peter

2009-12-01

We explore heat transfer in molecular junctions between two leads in the absence of a finite net thermal bias. The application of an unbiased time-periodic temperature modulation of the leads entails a dynamical breaking of reflection symmetry, such that a directed heat current may emerge (ratchet effect). In particular, we consider two cases of adiabatically slow driving, namely, (i) periodic temperature modulation of only one lead and (ii) temperature modulation of both leads with an ac driving that contains a second harmonic, thus, generating harmonic mixing. Both scenarios yield sizable directed heat currents, which should be detectable with present techniques. Adding a static thermal bias allows one to compute the heat current-thermal load characteristics, which includes the ratchet effect of negative thermal bias with positive-valued heat flow against the thermal bias, up to the thermal stop load. The ratchet heat flow in turn generates also an electric current. An applied electric stop voltage, yielding effective zero electric current flow, then mimics a solely heat-ratchet-induced thermopower ("ratchet Seebeck effect"), although no net thermal bias is acting. Moreover, we find that the relative phase between the two harmonics in scenario (ii) enables steering the net heat current into a direction of choice.

NCC: A Multidisciplinary Design/Analysis Tool for Combustion Systems

NASA Technical Reports Server (NTRS)

Liu, Nan-Suey; Quealy, Angela

1999-01-01

A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Lewis Research Center (LeRC), and Pratt & Whitney (P&W). This development team operates under the guidance of the NCC steering committee. The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration.

Diffusion of radon through concrete block walls: A significant source of indoor radon

USGS Publications Warehouse

Lively, R.S.; Goldberg, L.F.

1999-01-01

Basement modules located in southern Minnesota have been the site of continuous radon and environmental measurements during heating seasons since 1993. Concentrations of radon within the basement modules ranged from 70 Bq.m-3 to over 4000 Bq.m-3 between November to April during the three measurement periods. In the soil gas for the same times, concentrations of radon ranged between 25,000 and 70,000 Bq.m-3. Levels of radon within the basement modules changed by factors of five or more within 24 h, in concert with pressure gradients of 4 to 20 Pa that developed between the basement modules and their surroundings. Diffusion is identified as the principal method by which radon is transferred into and out of the basement modules, and appears to be relatively independent of insulating materials and vapour retarders. The variability of radon and correlations with differential pressure gradients may be related to air currents in the block walls and soil that interrupt radon diffusing inward. This yields a net decrease of radon in the basement modules by decay and outward diffusion. Levels of radon within the basement modules increase when the pressure differential is zero and air flow ceases, allowing diffusion gradients to be re-established. Radon levels in both the soil and the basement modules then increase until an equilibrium is achieved.

Start-up Characteristics of Swallow-tailed Axial-grooved Heat Pipe under the conditions of Multiple Heat Sources

NASA Astrophysics Data System (ADS)

Zhang, Renping

2017-12-01

A mathematical model was developed for predicting start-up characteristics of Swallow-tailed Axial-grooved Heat Pipe under the conditions of Multiple Heat Sources. The effects of heat capacitance of heat source, liquid-vapour interfacial evaporation-condensation heat transfer, shear stress at the interface was considered in current model. The interfacial evaporating mass flow rate is based on the kinetic analysis. Time variations of evaporating mass rate, wall temperature and liquid velocity are studied from the start-up to steady state. The calculated results show that wall temperature demonstrates step transition at the junction between the heat source and non-existent heat source on the evaporator. The liquid velocity changes drastically at the evaporator section, however, it has slight variation at the evaporator section without heat source. When the effect of heat source is ignored, the numerical temperature demonstrates a quicker response. With the consideration of capacitance of the heat source, the data obtained from the proposed model agree well with the experimental results.

Manned space flight nuclear system safety. Volume 4: Space shuttle nuclear system transportation. Part 1: Space shuttle nuclear safety

NASA Technical Reports Server (NTRS)

1972-01-01

An analysis of the nuclear safety aspects (design and operational considerations) in the transport of nuclear payloads to and from earth orbit by the space shuttle is presented. Three representative nuclear payloads used in the study were: (1) the zirconium hydride reactor Brayton power module, (2) the large isotope Brayton power system and (3) small isotopic heat sources which can be a part of an upper stage or part of a logistics module. Reference data on the space shuttle and nuclear payloads are presented in an appendix. Safety oriented design and operational requirements were identified to integrate the nuclear payloads in the shuttle mission. Contingency situations were discussed and operations and design features were recommended to minimize the nuclear hazards. The study indicates the safety, design and operational advantages in the use of a nuclear payload transfer module. The transfer module can provide many of the safety related support functions (blast and fragmentation protection, environmental control, payload ejection) minimizing the direct impact on the shuttle.

Development of data acquisition and over-current protection systems for a suppressor-grid current with a neutral-beam ion source

NASA Astrophysics Data System (ADS)

Wei, LIU; Chundong, HU; Sheng, LIU; Shihua, SONG; Jinxin, WANG; Yan, WANG; Yuanzhe, ZHAO; Lizhen, LIANG

2017-12-01

Neutral beam injection is one of the effective auxiliary heating methods in magnetic-confinement-fusion experiments. In order to acquire the suppressor-grid current signal and avoid the grid being damaged by overheating, a data acquisition and over-current protection system based on the PXI (PCI eXtensions for Instrumentation) platform has been developed. The system consists of a current sensor, data acquisition module and over-current protection module. In the data acquisition module, the acquired data of one shot will be transferred in isolation and saved in a data-storage server in a txt file. It can also be recalled using NBWave for future analysis. The over-current protection module contains two modes: remote and local. This gives it the function of setting a threshold voltage remotely and locally, and the forbidden time of over-current protection also can be set by a host PC in remote mode. Experimental results demonstrate that the data acquisition and over-current protection system has the advantages of setting forbidden time and isolation transmission.

Device and method for relativistic electron beam heating of a high-density plasma to drive fast liners

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner which is generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner.

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.

Retrieval of Latent Heating from TRMM Measurements

NASA Technical Reports Server (NTRS)

Tao, W.-K.; Smith, E. A.; Adler, R. F.; Hou, A. Y.; Meneghini, R.; Simpson, J.; Haddad, Z. S.; Iguchi, T.; Satoh, S.; Kakar, R.;

System design of the Pioneer Venus spacecraft. Volume 5: Probe vehicle studies

NASA Technical Reports Server (NTRS)

Nolte, L. J.; Stephenson, D. S.

1973-01-01

A summary of the key issues and studies conducted for the Pioneer Venus spacecraft and the resulting probe designs are presented. The key deceleration module issues are aerodynamic configuration and heat shield material selection. The design and development of the pressure vessel module are explained. Thermal control and science integration of the pressure vessel module are explained. The deceleration module heat shield, parachute and separation/despin are reported. The Thor/Delta and Atlas/Centaur baseline descriptions are provided.

A 3D TCAD simulation of a thermoelectric module configured for thermoelectric power generation, cooling and heating

NASA Astrophysics Data System (ADS)

Gould, C. A.; Shammas, N. Y. A.; Grainger, S.; Taylor, I.; Simpson, K.

2012-06-01

This paper documents the 3D modeling and simulation of a three couple thermoelectric module using the Synopsys Technology Computer Aided Design (TCAD) semiconductor simulation software. Simulation results are presented for thermoelectric power generation, cooling and heating, and successfully demonstrate the basic thermoelectric principles. The 3D TCAD simulation model of a three couple thermoelectric module can be used in the future to evaluate different thermoelectric materials, device structures, and improve the efficiency and performance of thermoelectric modules.

Engineering aspects of a thermal control subsystem for the 25 kW power module

NASA Technical Reports Server (NTRS)

Schroeder, P. E.

1979-01-01

The paper presents the key trade study results, analysis results, and the recommended thermal control approach for the 25 kW power module defined by NASA. Power conversion inefficiencies and component heat dissipation results in a minimum heat rejection requirement of 9 kW to maintain the power module equipment at desired temperature levels. Additionally, some cooling capacity should be provided for user payloads in the sortie and free-flying modes. The baseline thermal control subsystem includes a dual-loop-pumped Freon-21 coolant with the heat rejected from deployable existing orbiter radiators. Thermal analysis included an assessment of spacecraft orientations, radiator shapes and locations, and comparison of hybrid heat pipe and all liquid panels.

Modification of the Mathematical Model of the Thermoelectric Module of a Thermostating Coating

NASA Astrophysics Data System (ADS)

Zarubin, V. S.; Kuvyrkin, G. N.; Savel'eva, I. Yu.

2017-03-01

A modification has been made of the previously constructed mathematical model of a fragment of a flat thermostating coating including a thermoelectric module based on the variation formulation of the stationary problem of heat conduction in an inhomogeneous solid body. With the use of the Fourier finite integral transform the dependences have been obtained for calculating the temperature distribution in the heat insulating layer in the vicinity of the thermoelectric element and commutating conductors. This enabled us to refine one of the diagnostic variables of the model — the total heat resistance of the heat insulator between commutating plates and conductors of the thermoelectric module influencing the energy characteristics of the thermostating coating under investigation.

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

Baxter, Van D.; Rice, C. Keith; Munk, Jeffrey D.

Between October 2007 and September 2017, Oak Ridge National Laboratory (ORNL) and Lennox Industries, Inc. (Lennox) engaged in a Cooperative Research and Development Agreement (CRADA) to develop an air-source integrated heat pump (AS-IHP) system for the US residential market. The Lennox AS-IHP concept consisted of a high-efficiency air-source heat pump (ASHP) for space heating and cooling services and a separate heat pump water heater/dehumidifier (WH/DH) module for domestic water heating and dehumidification (DH) services. A key feature of this system approach with the separate WH/DH is capability to pretreat (i.e., dehumidify) ventilation air and dedicated whole-house DH independent of themore » ASHP. Two generations of laboratory prototype WH/DH units were designed, fabricated, and lab tested. Performance maps for the system were developed using the latest research version of the US Department of Energy/ORNL heat pump design model (Rice 1992; Rice and Jackson 2005; Shen et al. 2012) as calibrated against the lab test data. These maps served as the input to TRNSYS (Solar Energy Laboratory et al. 2010) to predict annual performance relative to a baseline suite of equipment meeting minimum efficiency standards in effect in 2006 (i.e., a combination of an ASHP with a seasonal energy efficiency ratio (SEER) of 13 and resistance water heater with an energy factor (EF) of 0.9). Predicted total annual energy savings (based on use of a two-speed ASHP and the second-generation WH/DH prototype for the AS-IHP), while providing space conditioning, water heating, and dehumidification for a tight, well-insulated 2600 ft2 (242 m2) house at three US locations, ranged from 33 to 36%, averaging 35%, relative to the baseline system. The lowest savings were seen at the cold-climate Chicago location. Predicted energy use for water heating was reduced by about 50 to 60% relative to a resistance WH.« less

Model documentation renewable fuels module of the National Energy Modeling System

NASA Astrophysics Data System (ADS)

1995-06-01

This report documents the objectives, analytical approach, and design of the National Energy Modeling System (NEMS) Renewable Fuels Module (RFM) as it relates to the production of the 1995 Annual Energy Outlook (AEO95) forecasts. The report catalogs and describes modeling assumptions, computational methodologies, data inputs, and parameter estimation techniques. A number of offline analyses used in lieu of RFM modeling components are also described. The RFM consists of six analytical submodules that represent each of the major renewable energy resources -- wood, municipal solid waste (MSW), solar energy, wind energy, geothermal energy, and alcohol fuels. The RFM also reads in hydroelectric facility capacities and capacity factors from a data file for use by the NEMS Electricity Market Module (EMM). The purpose of the RFM is to define the technological, cost, and resource size characteristics of renewable energy technologies. These characteristics are used to compute a levelized cost to be competed against other similarly derived costs from other energy sources and technologies. The competition of these energy sources over the NEMS time horizon determines the market penetration of these renewable energy technologies. The characteristics include available energy capacity, capital costs, fixed operating costs, variable operating costs, capacity factor, heat rate, construction lead time, and fuel product price.

Comparison of performance of high-power mid-IR QCL modules in actively and passively cooled mode

NASA Astrophysics Data System (ADS)

Münzhuber, F.; Denzel, H.; Tholl, H. D.

2017-10-01

We report on the effects of active and passive cooling on the performance of high power mid-IR QCL modules (λ ≈ 3.9 μm) in quasi-cw mode. In active cooling mode, a thermo-electrical cooler attached with its hot side to a heat sink of constant temperature, a local thermometer in close proximity to the QCL chip (epi-down mounted) as well as a control unit has been used for temperature control of the QCL submount. In contrast, the passive cooling was performed by attaching the QCL module solely to the heat sink. Electro-optical light-current- (L-I-) curves are measured in a quasi-cw mode, from which efficiencies can be deduced. Waiving of the active cooling elements results in a drop of the maximum intensity of less than 5 %, compared to the case wherein the temperature of the submount is stabilized to the temperature of the heat sink. The application of a model of electro-optical performance to the data shows good agreement and captures the relevant observations. We further determine the heat resistance of the module and demonstrate that the system performance is not limited by the packaging of the module, but rather by the heat dissipation on the QCL chip itself.

Io: Intensive Heating and Degassing, Rising and Falling Stripes In Crossing Wavy Patterns Do Not Require Molten Interior

NASA Astrophysics Data System (ADS)

Kochemasov, G.

"Orbits make structures". This fundamental concept unfolded in four theorems of the wave planetary tectonics [1] simply means that Keplerian non-circular orbits imply inertia forces which make planetary bodies oscillate and produce structures. Many examples of regular wave woven structures on surfaces of planets (and asteroids and comets - Borrelli !) and satellites prove it. Theorem 3 ("Celestial bodies are granular "[1]) connects a size of tectonic granulation with an orbital frequency. But what to do with satellites having more orbits than planets ? Here acts the wave modulation pro- cess. A low frequency modulates a high frequency producing lower and higher side frequencies. Actually we explained ubiquitous tectonic dichotomy (Theorem 1, [1]) by modulation of all frequencies in the Solar System (SS) by the very low galactic frequency of the SS. In this case we considered the lower side frequency. But at the opposite side there are the higher side frequencies which fall into a range of radio- and microwave frequencies so typical for bodies of the SS [2]. These higher side frequen- cies depend on a body's radius and its orbital frequency. For example, the Io orbital frequency is modulated by the Jupiter orbital frequency and by the galactic orbital frequency of the SS (1/12 years and ~1/200 000 000 years). The Io circumsolar fre- quency (together with Jupiter) is also modulated by the galactic frequency. So, there are three higher side frequencies for Io to which correspond three wavelengths: 4.62 km (Io orbits Jupiter),68 cm (Io's circumsolar orbit in the galactic orbit), 0.276 mm (Io's circumjovian orbit in the galactic orbit). For smaller and faster Amalthea these wave oscillations are: 93.2 m - 4.88 cm - 0.0056 mm. So "microwave stove" heating might be an appreciable source of heating for Io as well as for Amalthea (also anoma- lously heated body) [3]. Very variable Io's surface and very short wave (upto 10 m) crossing patterns are already observed. Io's 5 micron outbursts are reported [4]. They could be produced by the heated Io's body. Surprisingly, 5 micron (0.0056 mm) oscil- 1 lations we calculate for Amalthea. The 2002 y. meeting "Galileo" with Amalthea will bring additional information. References: [1] Kochemasov G.G.(1999) Theorems of wave planetary tectonics // Geophys. Res. Abstr., v.1, #3, 700; [2] Kochemasov G.G. (2001) Vernadsky-Brown 34th microsymp. Topics in comparative planetology. Abstr., Moscow, (CD-ROM); [3] Kochemasov G.G. (1997) Ibid. 26th, 58-59; [4]Sinton W.M. (1980) Astrophys.J., v. 235, #1, 149-151. 2

Modeling of a Stacked Power Module for Parasitic Inductance Extraction

DTIC Science & Technology

2017-09-15

issues of heat dissipation, reliability, and parasitic inductance. An improved packaging approach has been proposed to simultaneously address each of...and mechanical attachments. The power devices in the resulting module design are stacked between copper layers with an integrated heat sink. By...stacking devices, the module’s parasitic inductance should be reduced, with concurrent improvement of reliability and heat dissipation, in comparison to

Technical Report on DOMICE Simulation Model

DTIC Science & Technology

2012-04-01

Branch GPS Global Positioning System HHO home heating oil LCA Lake Carriers’ Association MAR USCG Domestic Icebreaking Mission Analysis...cargo types considered in the module. The module groups the four types of cargo into two broader categories, namely, Home Heating Oil ( HHO ) shipments...or Non- HHO shipments. Table 11. Cargo types. Types of Cargo Cargo Group Dry Bulk Non- HHO Liquid Bulk Perishable / Food Home Heating Oil HHO

Getting Down to Business: Air Conditioning and Heating Service, Module 36. [Student Guide]. Entrepreneurship Training Components.

ERIC Educational Resources Information Center

Sanderson, Barbara

This module on owning and operating an air conditioning and heating service is one of 36 in a series on entrepreneurship. The introduction tells the student what topics will be covered and suggests other modules to read in related occupations. Each unit includes student goals, a case study, and a discussion of the unit subject matter. Learning…

Heat Transfer Processes for the Thermal Energy Balance of Organisms. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

ERIC Educational Resources Information Center

Stevenson, R. D.

This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module describes heat transfer processes involved in the exchange of heat…

Diaphragm Stirling engine heat-actuated heat pump development

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

Ackermann, R.A.; Swenson, P.

1981-01-01

The objective of this program is to develop and demonstrate the performance of a diaphragm Stirling engine heat-actuated heat pump power module. The power module, consisting of a free displacer, resonant Stirling engine, hydraulic transmission, and resonant Rankine refrigerant (F-22) compressor, embodies several innovative concepts in free-piston Stirling engine heat pump design that will advance the state of the art of this technology. Progress is reported in three areas of the program. First, a compressor/engine matching analysis and a stability analysis have shown that the power module, which is representative of a two-degree-of-freedom resonant system, will operate stably over themore » full range of heat pump conditions. Second, a compressor design has evolved that has met criteria for performance and cost; and third, tests employing a hydraulic simulator test rig has shown that the transmission losses are less than had been predicted, and that properly designed and fabricated diaphragms can attain long life.« less

SAFSIM theory manual: A computer program for the engineering simulation of flow systems

NASA Astrophysics Data System (ADS)

Dobranich, Dean

1993-12-01

SAFSIM (System Analysis Flow SIMulator) is a FORTRAN computer program for simulating the integrated performance of complex flow systems. SAFSIM provides sufficient versatility to allow the engineering simulation of almost any system, from a backyard sprinkler system to a clustered nuclear reactor propulsion system. In addition to versatility, speed and robustness are primary SAFSIM development goals. SAFSIM contains three basic physics modules: (1) a fluid mechanics module with flow network capability; (2) a structure heat transfer module with multiple convection and radiation exchange surface capability; and (3) a point reactor dynamics module with reactivity feedback and decay heat capability. Any or all of the physics modules can be implemented, as the problem dictates. SAFSIM can be used for compressible and incompressible, single-phase, multicomponent flow systems. Both the fluid mechanics and structure heat transfer modules employ a one-dimensional finite element modeling approach. This document contains a description of the theory incorporated in SAFSIM, including the governing equations, the numerical methods, and the overall system solution strategies.

Loop Heat Pipe Operation Using Heat Source Temperature for Set Point Control

NASA Technical Reports Server (NTRS)

Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

2011-01-01

The LHP operating temperature is governed by the saturation temperature of its reservoir. Controlling the reservoir saturation temperature is commonly accomplished by cold biasing the reservoir and using electrical heaters to provide the required control power. Using this method, the loop operating temperature can be controlled within +/- 0.5K. However, because of the thermal resistance that exists between the heat source and the LHP evaporator, the heat source temperature will vary with its heat output even if LHP operating temperature is kept constant. Since maintaining a constant heat source temperature is of most interest, a question often raised is whether the heat source temperature can be used for LHP set point temperature control. A test program with a miniature LHP has been carried out to investigate the effects on the LHP operation when the control temperature sensor is placed on the heat source instead of the reservoir. In these tests, the LHP reservoir is cold-biased and is heated by a control heater. Tests results show that it is feasible to use the heat source temperature for feedback control of the LHP operation. Using this method, the heat source temperature can be maintained within a tight range for moderate and high powers. At low powers, however, temperature oscillations may occur due to interactions among the reservoir control heater power, the heat source mass, and the heat output from the heat source. In addition, the heat source temperature could temporarily deviate from its set point during fast thermal transients. The implication is that more sophisticated feedback control algorithms need to be implemented for LHP transient operation when the heat source temperature is used for feedback control.

Phase-coherent engineering of electronic heat currents with a Josephson modulator

NASA Astrophysics Data System (ADS)

Fornieri, Antonio; Blanc, Christophe; Bosisio, Riccardo; D'Ambrosio, Sophie; Giazotto, Francesco

In this contribution we report the realization of the first balanced Josephson heat modulator designed to offer full control at the nanoscale over the phase-coherent component of electronic thermal currents. The ability to master the amount of heat transferred through two tunnel-coupled superconductors by tuning their phase difference is the core of coherent caloritronics, and is expected to be a key tool in a number of nanoscience fields, including solid state cooling, thermal isolation, radiation detection, quantum information and thermal logic. Our device provides magnetic-flux-dependent temperature modulations up to 40 mK in amplitude with a maximum of the flux-to-temperature transfer coefficient reaching 200 mK per flux quantum at a bath temperature of 25 mK. Foremost, it demonstrates the exact correspondence in the phase-engineering of charge and heat currents, breaking ground for advanced caloritronic nanodevices such as thermal splitters, heat pumps and time-dependent electronic engines.

Refractory Metal Heat Pipe Life Test - Test Plan and Standard Operating Procedures

NASA Technical Reports Server (NTRS)

Martin, J. J.; Reid, R. S.

2010-01-01

Refractory metal heat pipes developed during this project shall be subjected to various operating conditions to evaluate life-limiting corrosion factors. To accomplish this objective, various parameters shall be investigated, including the effect of temperature and mass fluence on long-term corrosion rate. The test series will begin with a performance test of one module to evaluate its performance and to establish the temperature and power settings for the remaining modules. The performance test will be followed by round-the-clock testing of 16 heat pipes. All heat pipes shall be nondestructively inspected at 6-month intervals. At longer intervals, specific modules will be destructively evaluated. Both the nondestructive and destructive evaluations shall be coordinated with Los Alamos National Laboratory. During the processing, setup, and testing of the heat pipes, standard operating procedures shall be developed. Initial procedures are listed here and, as hardware is developed, will be updated, incorporating findings and lessons learned.

Near-chip compliant layer for reducing perimeter stress during assembly process

DOEpatents

Schultz, Mark D.; Takken, Todd E.; Tian, Shurong; Yao, Yuan

2018-03-20

A heat source (single semiconductor chip or group of closely spaced semiconductor chips of similar height) is provided on a first side of a substrate, which substrate has on said first side a support member comprising a compressible material. A heat removal component, oriented at an angle to said heat source, is brought into proximity of said heat source such that said heat removal component contacts said support member prior to contacting said heat source. Said heat removal component is assembled to said heat source such that said support member at least partially absorbs global inequality of force that would otherwise be applied to said heat source, absent said support member comprising said compressible material.

Near-chip compliant layer for reducing perimeter stress during assembly process

DOEpatents

Schultz, Mark D.; Takken, Todd E.; Tian, Shurong; Yao, Yuan

2017-02-14

A heat source (single semiconductor chip or group of closely spaced semiconductor chips of similar height) is provided on a first side of a substrate, which substrate has on said first side a support member comprising a compressible material. A heat removal component, oriented at an angle to said heat source, is brought into proximity of said heat source such that said heat removal component contacts said support member prior to contacting said heat source. Said heat removal component is assembled to said heat source such that said support member at least partially absorbs global inequality of force that would otherwise be applied to said heat source, absent said support member comprising said compressible material.

X-Ray and Optical Study of the Gamma-ray Source 3FGL J0838.8–2829: Identification of a Candidate Millisecond Pulsar Binary and an Asynchronous Polar

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

Halpern, Jules P.; Bogdanov, Slavko; Thorstensen, John R., E-mail: jules@astro.columbia.edu

2017-04-01

We observed the field of the Fermi source 3FGL J0838.8−2829 in optical and X-rays, initially motivated by the cataclysmic variable (CV) 1RXS J083842.1−282723 that lies within its error circle. Several X-ray sources first classified as CVs have turned out to be γ -ray emitting millisecond pulsars (MSPs). We find that 1RXS J083842.1−282723 is in fact an unusual CV, a stream-fed asynchronous polar in which accretion switches between magnetic poles (that are ≈120° apart) when the accretion rate is at minimum. High-amplitude X-ray modulation at periods of 94.8 ± 0.4 minutes and 14.7 ± 1.2 hr are seen. The former appearsmore » to be the spin period, while the latter is inferred to be one-third of the beat period between the spin and the orbit, implying an orbital period of 98.3 ± 0.5 minutes. We also measure an optical emission-line spectroscopic period of 98.413 ± 0.004 minutes, which is consistent with the orbital period inferred from the X-rays. In any case, this system is unlikely to be the γ -ray source. Instead, we find a fainter variable X-ray and optical source, XMMU J083850.38−282756.8, that is modulated on a timescale of hours in addition to exhibiting occasional sharp flares. It resembles the black widow or redback pulsars that have been discovered as counterparts of Fermi sources, with the optical modulation due to heating of the photosphere of a low-mass companion star by, in this case, an as-yet undetected MSP. We propose XMMU J083850.38−282756.8 as the MSP counterpart of 3FGL J0838.8−2829.« less

Thermal Conductivity of Single-Walled Carbon Nanotube with Internal Heat Source Studied by Molecular Dynamics Simulation

NASA Astrophysics Data System (ADS)

Li, Yuan-Wei; Cao, Bing-Yang

2013-12-01

The thermal conductivity of (5, 5) single-walled carbon nanotubes (SWNTs) with an internal heat source is investigated by using nonequilibrium molecular dynamics (NEMD) simulation incorporating uniform heat source and heat source-and-sink schemes. Compared with SWNTs without an internal heat source, i.e., by a fixed-temperature difference scheme, the thermal conductivity of SWNTs with an internal heat source is much lower, by as much as half in some cases, though it still increases with an increase of the tube length. Based on the theory of phonon dynamics, a function called the phonon free path distribution is defined to develop a simple one-dimensional heat conduction model considering an internal heat source, which can explain diffusive-ballistic heat transport in carbon nanotubes well.

Micro-Scalable Thermal Control Device

NASA Technical Reports Server (NTRS)

Moran, Matthew E. (Inventor)

2002-01-01

A microscalable thermal control module consists of a Stirling cycle cooler that can be manipulated to operate at a selected temperature within the heating and cooling range of the module. The microscalable thermal control module is particularly suited for controlling the temperature of devices that must be maintained at precise temperatures. It is particularly suited for controlling the temperature of devices that need to be alternately heated or cooled. The module contains upper and lower opposing diaphragms, with a regenerator region containing a plurality of regenerators interposed between the diaphragms. Gaps exist on each side of each diaphragm to permit it to oscillate freely. The gap on the interior side one diaphragm is in fluid connection with the gap on the interior side of the other diaphragm through regenerators. As the diaphragms oscillate working gas is forced through the regenerators. The surface area of each regenerator is sufficiently large to effectively transfer thermal energy to and from the working gas as it is passed through them. The phase and amplitude of the oscillations can be manipulated electronically to control the steady state temperature of the active thermal control surface, and to switch the operation of the module from cooling to heating, or vice versa. The ability of the microscalable thermal control module to heat and cool may be enhanced by operating a plurality of modules in series, in parallel, or in connection through a shared bottom layer.

Stark cell optoacoustic detection of constituent gases in sample

NASA Technical Reports Server (NTRS)

Margolis, J. S.; Shumate, M. S. (Inventor)

1980-01-01

An optoacoustic detector for gas analysis is implemented with Stark effect cell modulation for switching a beam in and out of coincidence with a spectral line of a constituent gas in order to eliminate the heating effect of laser energy in the cell as a source of background noise. By using a multiline laser, and linearly sweeping the DC bias voltage while exciting the cell with a multiline laser, it is possible to obtain a spectrum from which to determine the combinations of excited constituents and determine their concentrations in parts per million.

Ground-based observations and simulation of ionospheric VLF source in experiments on modification of the polar ionosphere

NASA Astrophysics Data System (ADS)

Lebed', O. M.; Fedorenko, Yu. V.; Blagoveshchenskaya, N. F.; Larchenko, A. V.; Grigor'ev, V. F.; Pil'gaev, S. V.

2017-11-01

The phase velocities of TE and TEM waves at frequencies of 1017 and 3017 Hz, as well as the effect of precipitations during auroras on the velocities, are estimated in the Earth-ionosphere waveguide on the basis of observations of electromagnetic fields of an ionospheric source in experiments on modification of the lower ionosphere by a modulated high-power short-wave signals performed by the Arctic and Antarctic Research Institute (AARI) at the EISCAT/Heating test bench in October 2016. Probable electron density profiles in the plane-stratified ionosphere are retrieved from the numerical solution of a wave equation, which are used for the calculation of the phase velocities close to measured ones.

Thermoelectric Generation Of Current - Theoretical And Experimental Analysis

NASA Astrophysics Data System (ADS)

Ruciński, Adam; Rusowicz, Artur

2017-12-01

This paper provides some information about thermoelectric technology. Some new materials with improved figures of merit are presented. These materials in Peltier modules make it possible to generate electric current thanks to a temperature difference. The paper indicates possible applications of thermoelectric modules as interesting tools for using various waste heat sources. Some zero-dimensional equations describing the conditions of electric power generation are given. Also, operating parameters of Peltier modules, such as voltage and electric current, are analyzed. The paper shows chosen characteristics of power generation parameters. Then, an experimental stand for ongoing research and experimental measurements are described. The authors consider the resistance of a receiver placed in the electric circuit with thermoelectric elements. Finally, both the analysis of experimental results and conclusions drawn from theoretical findings are presented. Voltage generation of about 1.5 to 2.5 V for the temperature difference from 65 to 85 K was observed when a bismuth telluride thermoelectric couple (traditionally used in cooling technology) was used.

Digitally controlled chirped pulse laser for sub-terahertz-range fiber structure interrogation.

PubMed

Chen, Zhen; Hefferman, Gerald; Wei, Tao

2017-03-01

This Letter reports a sweep velocity-locked laser pulse generator controlled using a digital phase-locked loop (DPLL) circuit. This design is used for the interrogation of sub-terahertz-range fiber structures for sensing applications that require real-time data collection with millimeter-level spatial resolution. A distributed feedback laser was employed to generate chirped laser pulses via injection current modulation. A DPLL circuit was developed to lock the optical frequency sweep velocity. A high-quality linearly chirped laser pulse with a frequency excursion of 117.69 GHz at an optical communication band was demonstrated. The system was further adopted to interrogate a continuously distributed sub-terahertz-range fiber structure (sub-THz-fs) for sensing applications. A strain test was conducted in which the sub-THz-fs showed a linear response to longitudinal strain change with predicted sensitivity. Additionally, temperature testing was conducted in which a heat source was used to generate a temperature distribution along the fiber structure to demonstrate its distributed sensing capability. A Gaussian temperature profile was measured using the described system and tracked in real time, as the heat source was moved.

Thermal diffusivity measurement of GaAs/AlGaAs thin-film structures

NASA Astrophysics Data System (ADS)

Chen, G.; Tien, C. L.; Wu, X.; Smith, J. S.

1994-05-01

This work develops a new measurement technique that determines the thermal diffusivity of thin films in both parallel and perpendicular directions, and presents experimental results on the thermal diffusivity of GaAs/AlGaAs-based thin-film structures. In the experiment, a modulated laser source heats up the sample and a fast-response temperature sensor patterned directly on the sample picks up the thermal response. From the phase delay between the heating source and the temperature sensor, the thermal diffusivity in either the parallel or perpendicular direction is obtained depending on the experimental configuration. The experiment is performed on a molecular-beam-epitaxy grown vertical-cavity surface-emitting laser (VCSEL) structure. The substrates of the samples are etched away to eliminate the effects of the interface between the film and the substrate. The results show that the thermal diffusivity of the VCSEL structure is 5-7 times smaller than that of its corresponding bulk media. The experiments also provide evidence on the anisotropy of thermal diffusivity caused solely by the effects of interfaces and boundaries of thin films.

New and future heat pump technologies

NASA Astrophysics Data System (ADS)

Creswick, F. A.

It is not possible to say for sure what future heat pumps will look like, but there are some interesting possibilities. In the next five years, we are likely to see US heat pumps with two kinds of innovations: capacity modulation and charge control. Capacity modulation will be accomplished by variable-speed compressor motors. The objective of charge control is to keep the refrigerant charge in the system where it belongs for best performance; there are probably many ways to accomplish this. Charge control will improve efficiency and durability; capacity modulation will further improve efficiency and comfort. The Stirling cycle heat pump has several interesting advantages, but it is farther out in time. At present, we don't know how to make it as efficient as the conventional vapor-compression heat pump. Electric utility people should be aware that major advances are being made in gas-fired heat pumps which could provide strong competition in the future. However, even a gas-fired heat pump has a substantial auxiliary electric power requirement. The resources needed to develop advanced heat pumps are substantial and foreign competition will be intense. It will be important for utilities, manufacturers, and the federal government to work in close cooperation.

Venus Mobile Explorer with RPS for Active Cooling: A Feasibility Study

NASA Technical Reports Server (NTRS)

Leifer, Stephanie D.; Green, Jacklyn R.; Balint, Tibor S.; Manvi, Ram

2009-01-01

We present our findings from a study to evaluate the feasibility of a radioisotope power system (RPS) combined with active cooling to enable a long-duration Venus surface mission. On-board power with active cooling technology featured prominently in both the National Research Council's Decadal Survey and in the 2006 NASA Solar System Exploration Roadmap as mission-enabling for the exploration of Venus. Power and cooling system options were reviewed and the most promising concepts modeled to develop an assessment tool for Venus mission planners considering a variety of future potential missions to Venus, including a Venus Mobile Explorer (either a balloon or rover concept), a long-lived Venus static lander, or a Venus Geophysical Network. The concepts modeled were based on the integration of General Purpose Heat Source (GPHS) modules with different types of Stirling cycle heat engines for power and cooling. Unlike prior investigations which reported on single point design concepts, this assessment tool allows the user to generate either a point design or parametric curves of approximate power and cooling system mass, power level, and number of GPHS modules needed for a "black box" payload housed in a spherical pressure vessel.

Device and method for electron beam heating of a high density plasma

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high density plasma in a small localized region. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target plasma is ionized prior to application of the electron beam by means of a laser or other preionization source. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region within the high density plasma target.

Radiation source

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the relativistic electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region of the high-density plasma target.

Orion Service Module Reaction Control System Plume Impingement Analysis Using PLIMP/RAMP2

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen J.; Gati, Frank; Yuko, James R.; Motil, Brian J.; Lumpkin, Forrest E.

2009-01-01

The Orion Crew Exploration Vehicle Service Module Reaction Control System engine plume impingement was computed using the plume impingement program (PLIMP). PLIMP uses the plume solution from RAMP2, which is the refined version of the reacting and multiphase program (RAMP) code. The heating rate and pressure (force and moment) on surfaces or components of the Service Module were computed. The RAMP2 solution of the flow field inside the engine and the plume was compared with those computed using GASP, a computational fluid dynamics code, showing reasonable agreement. The computed heating rate and pressure using PLIMP were compared with the Reaction Control System plume model (RPM) solution and the plume impingement dynamics (PIDYN) solution. RPM uses the GASP-based plume solution, whereas PIDYN uses the SCARF plume solution. Three sets of the heating rate and pressure solutions agree well. Further thermal analysis on the avionic ring of the Service Module showed that thermal protection is necessary because of significant heating from the plume.

Thermal equilibrium control by frequent bang-bang modulation.

PubMed

Yang, Cheng-Xi; Wang, Xiang-Bin

2010-05-01

In this paper, we investigate the non-Markovian heat transfer between a weakly damped harmonic oscillator (system) and a thermal bath. When the system is initially in a thermal state and not correlated with the environment, the mean energy of the system always first increases, then oscillates, and finally reaches equilibrium with the bath, no matter what the initial temperature of the system is. Moreover, the heat transfer between the system and the bath can be controlled by fast bang-bang modulation. This modulation does work on the system, and temporarily inverts the direction of heat flow. In this case, the common sense that heat always transfers from hot to cold does not hold any more. At the long time scale, a new dynamic equilibrium is established between the system and the bath. At this equilibrium, the energy of the system can be either higher or lower than its normal equilibrium value. A comprehensive analysis of the relationship between the dynamic equilibrium and the parameters of the modulation as well as the environment is presented.

Nonreciprocal Thermal Material by Spatiotemporal Modulation

NASA Astrophysics Data System (ADS)

Torrent, Daniel; Poncelet, Olivier; Batsale, Jean-Chirstophe

2018-03-01

The thermal properties of a material with a spatiotemporal modulation, in the form of a traveling wave, in both the thermal conductivity and the specific heat capacity are studied. It is found that these materials behave as materials with an internal convectionlike term that provides them with nonreciprocal properties, in the sense that the heat flux has different properties when it propagates in the same direction or in the opposite one to the modulation of the parameters. An effective medium description is presented which accurately describes the modulated material, and numerical simulations support this description and verify the nonreciprocal properties of the material. It is found that these materials are promising candidates for the design of thermal diodes and other advanced devices for the control of the heat flow at all scales.

Indoor and outdoor weathering of PV-modules

NASA Astrophysics Data System (ADS)

Koehl, Michael; Heck, Markus; Philipp, Daniel; Weiss, Karl-Anders; Ferrara, Claudio; Herrmann, Werner

2008-08-01

Manufacturers of PV-modules usually give a warranty for at least 20 years. There is still only little knowledge about the lifetime of newly developed modules, however. How do they cope with snow, desert-climate or tropical humidity? In order to answer this question the Fraunhofer-Institute for Solar Energy Systems and TUV Rheinland have installed different outdoor exposure sites where modules have to stand extreme climates: high temperatures with high differences between day and night in the Negev desert at Israel, snow, wind and changing irradiation in the German Alps, and high humidity at warm temperatures at Indonesia. Commercial modules from industrial partners as well as innovative modules with different combinations of encapsulants and back-sheets were exposed. UV-irradiation, solar-irradiation, ambient- and module temperatures, ambient humidity and wind speed is measured and collected at a central server in Germany. These data are the basis for the calculation of integral loads for the comparison of different climatic regions and for an estimation of the service life, an exciting field of work since decades. Results from the evaluation of the monitoring during the fist 12 months of exposure are compared. Fluorescent lamps are chosen for accelerated UV-testing, since they simulate the UV-irradiation of the sun well while emitting less thermal radiation than Xenon-lamps. The UV-source is designed for use in climatic cabinets for damp-heat testing with UV.

Strain-induced modulation of near-field radiative transfer.

PubMed

Ghanekar, Alok; Ricci, Matthew; Tian, Yanpei; Gregory, Otto; Zheng, Yi

2018-06-11

In this theoretical study, we present a near-field thermal modulator that exhibits change in radiative heat transfer when subjected to mechanical stress/strain. The device has two terminals at different temperatures separated by vacuum: one fixed and one stretchable. The stretchable side contains one-dimensional grating. When subjected to mechanical strain, the effective optical properties of the stretchable side are affected upon deformation of the grating. This results in modulation of surface waves across the interfaces influencing near-field radiative heat transfer. We show that for a separation of 100 nm, it is possible to achieve 25% change in radiative heat transfer for a strain of 10%.

NASA's Global Climate Change Education (GCCE) Program: New modules

NASA Astrophysics Data System (ADS)

Witiw, M. R.; Myers, R. J.; Schwerin, T. G.

2010-12-01

In existence for over 10 years, the Earth System Science Educational Alliance (ESSEA) through the Institute of Global Environmental Strategies (IGES) has developed a series of modules on Earth system science topics. To date, over 80 educational modules have been developed. The primary purpose of these modules is to provide graduate courses for teacher education. A typical course designed for teachers typically consists of from three to five content modules and a primer on problem-based learning. Each module is designed to take three weeks in a normal university semester. Course delivery methods vary. Some courses are completed totally online. Others are presented in the classroom. Still others are delivered using a hybrid method which combines classroom meetings with online delivery of content. Although originally designed for teachers and education students, recent changes, provide a format for general education students to use these module. In 2009, under NASA’s Global Climate Change Education (GCCE) initiative, IGES was tasked to develop 16 new modules addressing the topic of climate change. Two of the modules recently developed under this program address the topics of sunspots and thermal islands. Sunspots is a problem-based learning module where students are provided resources and sample investigations related to sunspots. The history of sunspot observations, the structure of sunspots and the possible role sunspots may have in Earth’s climate are explored. Students are then asked to determine what effects a continued minimum in sunspot activity may have on the climate system. In Thermal Islands, the topic of urban heat islands is addressed. How heat islands are produced and the role of urban heat islands in exacerbating heat waves are two of the topics covered in the resources. In this problem-based learning module, students are asked to think of mitigating strategies for these thermal islands as Earth’s urban population grows over the next 50 years. These modules were successfully piloted with undergraduate students at Seattle Pacific University.

Thermoelectric System Absorbing Waste Heat from a Steel Ladle

NASA Astrophysics Data System (ADS)

Lu, Baiyi; Meng, Xiangning; Zhu, Miaoyong; Suzuki, Ryosuke O.

2018-06-01

China's iron and steel industry has made great progress in energy savings and emission reductions with the application of many waste heat recovery technologies. However, most of the medium and low temperature waste heat and radiant waste heat has not been effectively utilized. This paper proposes a thermoelectric system that generates electricity by absorbing the radiant heat from the surface of steel ladles in a steel plant. The thermoelectric behavior of modules in this system is analyzed by a numerical simulation method. The effects of external resistance and module structure on thermoelectric performance are also discussed in the temperature range of the wall surface of a steel ladle. The results show that the wall temperature has a significant influence on the thermoelectric behavior of the module, so its uniformity and stability should be considered in practical application. The ratio of the optimum external resistance to the internal resistance of the thermoelectric module is in the range of 1.6-2.0, which indicates the importance of external load optimization for a given thermoelectric system. In addition, the output power and the conversion efficiency of the module can be significantly improved by increasing the length of the thermoelectric legs and adopting a double-layer structure. Finally, through the optimization of external resistance and structure, the power output can reach 83-304 W/m2. This system is shown to be a promising approach for energy recovery.

Conceptual design of a thermal control system for an inflatable lunar habitat module

NASA Technical Reports Server (NTRS)

Gadkari, Ketan; Goyal, Sanjay K.; Vanniasinkam, Joseph

1991-01-01

NASA is considering the establishment of a manned lunar base within the next few decades. To house and protect the crew from the harsh lunar environment, a habitat is required. A proposed habitat is an spherical, inflatable module. Heat generated in the module must be rejected to maintain a temperature suitable for human habitation. This report presents a conceptual design of a thermal control system for an inflatable lunar module. The design solution includes heat acquisition, heat transport, and heat rejection subsystems. The report discusses alternative designs and design solutions for each of the three subsystems mentioned above. Alternative subsystems for heat acquisition include a single water-loop, a single air-loop, and a double water-loop. The vapor compression cycle, vapor absorption cycle, and metal hydride absorption cycle are the three alternative transport subsystems. Alternative rejection subsystems include flat plate radiators, the liquid droplet radiator, and reflux boiler radiators. Feasibility studies on alternatives of each subsystem showed that the single water-loop, the vapor compression cycle, and the reflux boiler radiator were the most feasible alternatives. The design team combined the three subsystems to come up with an overall system design. Methods of controlling the system to adapt it for varying conditions within the module and in the environment are presented. Finally, the report gives conclusions and recommendations for further study of thermal control systems for lunar applications.

Thermoelectric System Absorbing Waste Heat from a Steel Ladle

NASA Astrophysics Data System (ADS)

Lu, Baiyi; Meng, Xiangning; Zhu, Miaoyong; Suzuki, Ryosuke O.

2018-01-01

China's iron and steel industry has made great progress in energy savings and emission reductions with the application of many waste heat recovery technologies. However, most of the medium and low temperature waste heat and radiant waste heat has not been effectively utilized. This paper proposes a thermoelectric system that generates electricity by absorbing the radiant heat from the surface of steel ladles in a steel plant. The thermoelectric behavior of modules in this system is analyzed by a numerical simulation method. The effects of external resistance and module structure on thermoelectric performance are also discussed in the temperature range of the wall surface of a steel ladle. The results show that the wall temperature has a significant influence on the thermoelectric behavior of the module, so its uniformity and stability should be considered in practical application. The ratio of the optimum external resistance to the internal resistance of the thermoelectric module is in the range of 1.6-2.0, which indicates the importance of external load optimization for a given thermoelectric system. In addition, the output power and the conversion efficiency of the module can be significantly improved by increasing the length of the thermoelectric legs and adopting a double-layer structure. Finally, through the optimization of external resistance and structure, the power output can reach 83-304 W/m2. This system is shown to be a promising approach for energy recovery.

Heat-Responsive Photosynthetic and Signaling Pathways in Plants: Insight from Proteomics.

PubMed

Wang, Xiaoli; Xu, Chenxi; Cai, Xiaofeng; Wang, Quanhua; Dai, Shaojun

2017-10-20

Heat stress is a major abiotic stress posing a serious threat to plants. Heat-responsive mechanisms in plants are complicated and fine-tuned. Heat signaling transduction and photosynthesis are highly sensitive. Therefore, a thorough understanding of the molecular mechanism in heat stressed-signaling transduction and photosynthesis is necessary to protect crop yield. Current high-throughput proteomics investigations provide more useful information for underlying heat-responsive signaling pathways and photosynthesis modulation in plants. Several signaling components, such as guanosine triphosphate (GTP)-binding protein, nucleoside diphosphate kinase, annexin, and brassinosteroid-insensitive I-kinase domain interacting protein 114, were proposed to be important in heat signaling transduction. Moreover, diverse protein patterns of photosynthetic proteins imply that the modulations of stomatal CO₂ exchange, photosystem II, Calvin cycle, ATP synthesis, and chlorophyll biosynthesis are crucial for plant heat tolerance.

Latent Heating from TRMM Satellite Measurements

NASA Technical Reports Server (NTRS)

Tao, Wei-Kuo; Smith, E. A.; Adler, R.; Haddad, Z.; Hou, A.; Iguchi, T.; Kakar, R.; Krishnamurti, T.; Kummerow, C.; Lang, S.

2004-01-01

Rainfall production is the fundamental variable within the Earth's hydrological cycle because it is both the principal forcing term in surface water budgets and its energetics corollary, latent heating, is the principal source of atmospheric diabatic heating. Latent heat release itself is a consequence of phase changes between the vapor, liquid, and frozen states of water. The properties of the vertical distribution of latent heat release modulate large-scale meridional and zonal circulations within the tropics - as well as modifying the energetic efficiencies of midlatitude weather systems. This paper focuses on the retrieval of latent heat release from satellite measurements generated by the Tropical Rainfall Measuring Mission (TRMM) satellite observatory, which was launched in November 1997 as a joint American-Japanese space endeavor. Since then, TRMM measurements have been providing an accurate four-dimensional account of rainfall over the global tropics and sub-tropics, information which can be used to estimate the space-time structure of latent heating across the Earth's low latitudes. The paper examines how the observed TRMM distribution of rainfall has advanced an understanding of the global water and energy cycle and its consequent relationship to the atmospheric general circulation and climate via latent heat release. A set of algorithm methodologies that are being used to estimate latent heating based on rain rate retrievals from the TRMM observations are described. The characteristics of these algorithms and the latent heating products that can be generated from them are also described, along with validation analyses of the heating products themselves. Finally, the investigation provides an overview of how TRMM-derived latent heating information is currently being used in conjunction with global weather and climate models, concluding with remarks intended to stimulate further research on latent heating retrieval from satellites.

Development of a three-dimensional core dynamics analysis program for commercial boiling water reactors

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

Bessho, Yasunori; Yokomizo, Osamu; Yoshimoto, Yuichiro

1997-03-01

Development and qualification results are described for a three-dimensional, time-domain core dynamics analysis program for commercial boiling water reactors (BWRs). The program allows analysis of the reactor core with a detailed mesh division, which eliminates calculational ambiguity in the nuclear-thermal-hydraulic stability analysis caused by reactor core regional division. During development, emphasis was placed on high calculational speed and large memory size as attained by the latest supercomputer technology. The program consists of six major modules, namely a core neutronics module, a fuel heat conduction/transfer module, a fuel channel thermal-hydraulic module, an upper plenum/separator module, a feedwater/recirculation flow module, and amore » control system module. Its core neutronics module is based on the modified one-group neutron kinetics equation with the prompt jump approximation and with six delayed neutron precursor groups. The module is used to analyze one fuel bundle of the reactor core with one mesh (region). The fuel heat conduction/transfer module solves the one-dimensional heat conduction equation in the radial direction with ten nodes in the fuel pin. The fuel channel thermal-hydraulic module is based on separated three-equation, two-phase flow equations with the drift flux correlation, and it analyzes one fuel bundle of the reactor core with one channel to evaluate flow redistribution between channels precisely. Thermal margin is evaluated by using the GEXL correlation, for example, in the module.« less

RTG Waste Heat System for the Cassini Propulsion Module

NASA Technical Reports Server (NTRS)

Mireles, V.; Stultz, J.

1994-01-01

This paper describes the thermal design for the propulsion module subsystem (PMS), and presents the results from the radioisotope thermoelectric generator (RTG) waste heat thermal test, and it summarizes the adjustment techniques and their relative effectiveness; it also shows the resulting predicted PMS flight temperatures relative to the requirements.

Sequencing-based gene network analysis provides a core set of gene resource for understanding thermal adaptation in Zhikong scallop Chlamys farreri.

PubMed

Fu, X; Sun, Y; Wang, J; Xing, Q; Zou, J; Li, R; Wang, Z; Wang, S; Hu, X; Zhang, L; Bao, Z

2014-01-01

Marine organisms are commonly exposed to variable environmental conditions, and many of them are under threat from increased sea temperatures caused by global climate change. Generating transcriptomic resources under different stress conditions are crucial for understanding molecular mechanisms underlying thermal adaptation. In this study, we conducted transcriptome-wide gene expression profiling of the scallop Chlamys farreri challenged by acute and chronic heat stress. Of the 13 953 unique tags, more than 850 were significantly differentially expressed at each time point after acute heat stress, which was more than the number of tags differentially expressed (320-350) under chronic heat stress. To obtain a systemic view of gene expression alterations during thermal stress, a weighted gene coexpression network was constructed. Six modules were identified as acute heat stress-responsive modules. Among them, four modules involved in apoptosis regulation, mRNA binding, mitochondrial envelope formation and oxidation reduction were downregulated. The remaining two modules were upregulated. One was enriched with chaperone and the other with microsatellite sequences, whose coexpression may originate from a transcription factor binding site. These results indicated that C. farreri triggered several cellular processes to acclimate to elevated temperature. No modules responded to chronic heat stress, suggesting that the scallops might have acclimated to elevated temperature within 3 days. This study represents the first sequencing-based gene network analysis in a nonmodel aquatic species and provides valuable gene resources for the study of thermal adaptation, which should assist in the development of heat-tolerant scallop lines for aquaculture. © 2013 John Wiley & Sons Ltd.

Temperature modulation with an esophageal heat transfer device - a pediatric swine model study.

PubMed

Kulstad, Erik B; Naiman, Melissa; Shanley, Patrick; Garrett, Frank; Haryu, Todd; Waller, Donald; Azarafrooz, Farshid; Courtney, Daniel Mark

2015-01-01

An increasing number of conditions appear to benefit from control and modulation of temperature, but available techniques to control temperature often have limitations, particularly in smaller patients with high surface to mass ratios. We aimed to evaluate a new method of temperature modulation with an esophageal heat transfer device in a pediatric swine model, hypothesizing that clinically significant modulation in temperature (both increases and decreases of more than 1°C) would be possible. Three female Yorkshire swine averaging 23 kg were anesthetized with inhalational isoflurane prior to placement of the esophageal device, which was powered by a commercially available heat exchanger. Swine temperature was measured rectally and cooling and warming were performed by selecting the appropriate external heat exchanger mode. Temperature was recorded over time in order to calculate rates of temperature change. Histopathology of esophageal tissue was performed after study completion. Average swine baseline temperature was 38.3°C. Swine #1 exhibited a cooling rate of 3.5°C/hr; however, passive cooling may have contributed to this rate. External warming blankets maintained thermal equilibrium in swine #2 and #3, demonstrating maximum temperature decrease of 1.7°C/hr. Warming rates averaged 0.29°C/hr. Histopathologic analysis of esophageal tissue showed no adverse effects. An esophageal heat transfer device successfully modulated the temperature in a pediatric swine model. This approach to temperature modulation may offer a useful new modality to control temperature in conditions warranting temperature management (such as maintenance of normothermia, induction of hypothermia, fever control, or malignant hyperthermia).

Simulation Analysis of Tilted Polyhedron-Shaped Thermoelectric Elements

NASA Astrophysics Data System (ADS)

Meng, Xiangning; Suzuki, Ryosuke O.

2015-06-01

The generation of thermoelectricity is considered a promising approach to harness the waste heat generated in industries, automobiles, gas fields, and other man-made processes. The waste heat can be converted to electricity via a thermoelectric (TE) generator. In this light, the generator performance depends on the geometric configuration of its constituent elements as well as their material properties. Our previous work reported TE behaviors for modules consisting of parallelogram-shaped elements, because elements with tilted laminate structures provide increased mechanical stability and efficient heat-transferring ability from the hot surface to the cold surface. Here, we study TE elements in the shape of a polyhedron that is obtained by mechanically truncating the edges of a parallelogram element in order to further enhance the generator performance and reduce TE material usage. The TE performance of the modules consisting of these polyhedron elements is numerically simulated by using the finite-volume method. The output power, voltage, and current of the polyhedral TE module are greater than those of the parallelogram-element module. The polyhedron shape positively affects heat transfer and the flow of electric charges in the light of increasing the efficiency of conversion from heat to electricity. By varying the shape of the truncated portions, we determine the optimal shape that enables homogeneous heat flux distribution and slow diffusion of thermal energy to obtain the better efficiency of conversion of heat into electricity. We believe that the findings of our study can significantly contribute to the design policy in TE generation.

Solar thermoelectric cooling using closed loop heat exchangers with macro channels

NASA Astrophysics Data System (ADS)

Atta, Raghied M.

2017-07-01

In this paper we describe the design, analysis and experimental study of an advanced coolant air conditioning system which cools or warms airflow using thermoelectric (TE) devices powered by solar cells. Both faces of the TE devices are directly connected to closed-loop highly efficient channels plates with macro scale channels and liquid-to-air heat exchangers. The hot side of the system consists of a pump that moves a coolant through the hot face of the TE modules, a radiator that drives heat away into the air, and a fan that transfer the heat over the radiator by forced convection. The cold side of the system consists also of a pump that moves coolant through the cold face of the TE modules, a radiator that drives cold away into the air, and a fan that blows cold air off the radiator. The system was integrated with solar panels, tested and its thermal performance was assessed. The experimental results verify the possibility of heating or cooling air using TE modules with a relatively high coefficient of performance (COP). The system was able to cool a closed space of 30 m3 by 14 °C below ambient within 90 min. The maximum COP of the whole system was 0.72 when the TE modules were running at 11.2 Å and 12 V. This improvement in the system COP over the air cooled heat sink is due to the improvement of the system heat exchange by means of channels plates.

ELF/VLF Wave Generation and Scattering from Modulated Heating of the Ionosphere at Arecibo Observatory

NASA Astrophysics Data System (ADS)

Maxworth, A. S.; Golkowski, M.; McCormick, J.; Cohen, M.; Hosseini, P.; Bittle, J.

2017-12-01

The recently completed ionospheric heater at Arecibo Observatory is used for modulated HF (5 or 8 MHz) heating of the ionosphere, to generate ELF/VLF (3 Hz - 30 kHz) waves. Observation of ramp and tone signals at frequencies from hundreds of Hz to several kHz at multiple receivers confirms the ability of the heater to modulate D region currents and create an ELF/VLF antenna in the ionosphere. Observed ELF/VLF signal amplitudes are lower than for similar experiments performed at high latitudes at the HAARP and Tromso facilities, for a variety of reasons including the reduced natural currents at mid latitudes, and the lower HF power of the Arecibo heater. The heating of the overhead ionosphere is also observed to change the Earth-ionosphere waveguide propagation characteristics as is evident from simultaneous observations of lightning induced sferics and VLF transmitter signals that propagate under the heated region. The active heating of the ionosphere modifies the reflection of incident VLF (3-30 kHz) waves. We present initial observations of HF heating of the D-region and resulting ELF/VLF wave generation.

Performance Analysis of Thermoelectric Modules Consisting of Square Truncated Pyramid Elements Under Constant Heat Flux

NASA Astrophysics Data System (ADS)

Oki, Sae; Natsui, Shungo; Suzuki, Ryosuke O.

2018-01-01

System design of a thermoelectric (TE) power generation module is pursued in order to improve the TE performance. Square truncated pyramid shaped P-N pairs of TE elements are connected electronically in series in the open space between two flat insulator boards. The performance of the TE module consisting of 2-paired elements is numerically simulated using commercial software and original TE programs. Assuming that the heat radiating into the hot surface is regulated, i.e., the amount of heat from the hot surface to the cold one is steadily constant, as it happens for solar radiation heating, the performance is significantly improved by changing the shape and the alignment pattern of the elements. When the angle θ between the edge and the base is smaller than 72°, and when the cold surface is kept at a constant temperature, two patterns in particular, amongst the 17 studied, show the largest TE power and efficiency. In comparison to other geometries, the smarter square truncated pyramid shape can provide higher performance using a large cold bath and constant heat transfer by heat radiation.

Performance Analysis of Thermoelectric Modules Consisting of Square Truncated Pyramid Elements Under Constant Heat Flux

NASA Astrophysics Data System (ADS)

Oki, Sae; Natsui, Shungo; Suzuki, Ryosuke O.

2018-06-01

System design of a thermoelectric (TE) power generation module is pursued in order to improve the TE performance. Square truncated pyramid shaped P-N pairs of TE elements are connected electronically in series in the open space between two flat insulator boards. The performance of the TE module consisting of 2-paired elements is numerically simulated using commercial software and original TE programs. Assuming that the heat radiating into the hot surface is regulated, i.e., the amount of heat from the hot surface to the cold one is steadily constant, as it happens for solar radiation heating, the performance is significantly improved by changing the shape and the alignment pattern of the elements. When the angle θ between the edge and the base is smaller than 72°, and when the cold surface is kept at a constant temperature, two patterns in particular, amongst the 17 studied, show the largest TE power and efficiency. In comparison to other geometries, the smarter square truncated pyramid shape can provide higher performance using a large cold bath and constant heat transfer by heat radiation.

Conversion efficiency of skutterudite-based thermoelectric modules.

PubMed

Salvador, James R; Cho, Jung Y; Ye, Zuxin; Moczygemba, Joshua E; Thompson, Alan J; Sharp, Jeffrey W; Koenig, Jan D; Maloney, Ryan; Thompson, Travis; Sakamoto, Jeffrey; Wang, Hsin; Wereszczak, Andrew A

2014-06-28

Presently, the only commercially available power generating thermoelectric (TE) modules are based on bismuth telluride (Bi2Te3) alloys and are limited to a hot side temperature of 250 °C due to the melting point of the solder interconnects and/or generally poor power generation performance above this point. For the purposes of demonstrating a TE generator or TEG with higher temperature capability, we selected skutterudite based materials to carry forward with module fabrication because these materials have adequate TE performance and are mechanically robust. We have previously reported the electrical power output for a 32 couple skutterudite TE module, a module that is type identical to ones used in a high temperature capable TEG prototype. The purpose of this previous work was to establish the expected power output of the modules as a function of varying hot and cold side temperatures. Recent upgrades to the TE module measurement system built at the Fraunhofer Institute for Physical Measurement Techniques allow for the assessment of not only the power output, as previously described, but also the thermal to electrical energy conversion efficiency. Here we report the power output and conversion efficiency of a 32 couple, high temperature skutterudite module at varying applied loading pressures and with different interface materials between the module and the heat source and sink of the test system. We demonstrate a 7% conversion efficiency at the module level when a temperature difference of 460 °C is established. Extrapolated values indicate that 7.5% is achievable when proper thermal interfaces and loading pressures are used.

Variable pressure power cycle and control system

DOEpatents

Goldsberry, Fred L.

1984-11-27

A variable pressure power cycle and control system that is adjustable to a variable heat source is disclosed. The power cycle adjusts itself to the heat source so that a minimal temperature difference is maintained between the heat source fluid and the power cycle working fluid, thereby substantially matching the thermodynamic envelope of the power cycle to the thermodynamic envelope of the heat source. Adjustments are made by sensing the inlet temperature of the heat source fluid and then setting a superheated vapor temperature and pressure to achieve a minimum temperature difference between the heat source fluid and the working fluid.

Latent Heating Retrievals Using the TRMM Precipitation Radar: A Multi-Seasonal Study

NASA Technical Reports Server (NTRS)

Tao, Wei-Kuo; Lang, S.; Meneghini, R.; Halverson, J.; Johnson, R.; Simpson, J.; Einaudi, Franco (Technical Monitor)

2001-01-01

Rainfall is a key link in the hydrologic cycle and is a primary heat source for the atmosphere. The vertical distribution of latent heat release, which is accompanied by rainfall, modulates the large-scale circulations of the tropics and in turn can impact midlatitude weather. This latent heat release is a consequence of phase changes between vapor, liquid, and solid water. Present largescale weather and climate models can simulate latent heat release only crudely, thus reducing their confidence in predictions on both global and regional scales. This paper represents the first attempt to use NASA Tropical Rainfall Measuring Mission (TRMM) rainfall information to estimate the four-dimensional structure of global monthly latent heating profiles over the global tropics from December 1997 to October 2000. The Goddard Convective-Stratiform. Heating (CSH) algorithm and TRMM precipitation radar data are used for this study. We will examine and compare the latent heating structures between 1997-1998 (winter) ENSO and 1998-2000 (non-ENSO). We will also examine over the tropics. The seasonal variation of heating over various geographic locations (i.e., oceanic vs continental; Indian oceans vs west Pacific; Africa vs S. America) will be also examined and compared. In addition, we will examine the relationship between latent heating (max heating level) and SST. The period of interest also coincides with several TRMM field campaigns that recently occurred over the South China Sea in 1998 (SCSMEX), Brazil in 1999 (TRMM-LBA), and in the central Pacific in 1999 (KWAJEX). Sounding diagnosed Q1 budgets from these experiments could provide a means of validating the retrieved profiles of latent heating from the CSH algorithm.

Variable temperature seat climate control system

DOEpatents

Karunasiri, Tissa R.; Gallup, David F.; Noles, David R.; Gregory, Christian T.

1997-05-06

A temperature climate control system comprises a variable temperature seat, at least one heat pump, at least one heat pump temperature sensor, and a controller. Each heat pump comprises a number of Peltier thermoelectric modules for temperature conditioning the air in a main heat exchanger and a main exchanger fan for passing the conditioned air from the main exchanger to the variable temperature seat. The Peltier modules and each main fan may be manually adjusted via a control switch or a control signal. Additionally, the temperature climate control system may comprise a number of additional temperature sensors to monitor the temperature of the ambient air surrounding the occupant as well as the temperature of the conditioned air directed to the occupant. The controller is configured to automatically regulate the operation of the Peltier modules and/or each main fan according to a temperature climate control logic designed both to maximize occupant comfort during normal operation, and minimize possible equipment damage, occupant discomfort, or occupant injury in the event of a heat pump malfunction.

Non-contact method for characterization of small size thermoelectric modules.

PubMed

Manno, Michael; Yang, Bao; Bar-Cohen, Avram

2015-08-01

Conventional techniques for characterization of thermoelectric performance require bringing measurement equipment into direct contact with the thermoelectric device, which is increasingly error prone as device size decreases. Therefore, the novel work presented here describes a non-contact technique, capable of accurately measuring the maximum ΔT and maximum heat pumping of mini to micro sized thin film thermoelectric coolers. The non-contact characterization method eliminates the measurement errors associated with using thermocouples and traditional heat flux sensors to test small samples and large heat fluxes. Using the non-contact approach, an infrared camera, rather than thermocouples, measures the temperature of the hot and cold sides of the device to determine the device ΔT and a laser is used to heat to the cold side of the thermoelectric module to characterize its heat pumping capacity. As a demonstration of the general applicability of the non-contact characterization technique, testing of a thin film thermoelectric module is presented and the results agree well with those published in the literature.

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

Sun, Xingshu; Silverman, Timothy J.; Zhou, Zhiguang

For commercial one-sun solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20-30 °C higher than the ambient. In the long term, extreme self-heating erodes efficiency and shortens lifetime, thereby dramatically reducing the total energy output. Therefore, it is critically important to develop effective and practical (and preferably passive) cooling methods to reduce operating temperature of photovoltaic (PV) modules. In this paper, we explore two fundamental (but often overlooked) origins of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical properties of themore » solar module to eliminate parasitic absorption (selective-spectral cooling) and enhance thermal emission (radiative cooling). Comprehensive opto-electro-thermal simulation shows that the proposed techniques would cool one-sun terrestrial solar modules up to 10 °C. As a result, this self-cooling would substantially extend the lifetime for solar modules, with corresponding increase in energy yields and reduced levelized cost of electricity.« less

Developing instrumentation to characterize thermoelectric generator modules.

PubMed

Liu, Dawei; Li, Qiming; Peng, Wenbo; Zhu, Lianjun; Gao, Hu; Meng, Qingsen; Jin, A J

2015-03-01

Based on the law of physics, known as "Seebeck effect," a thermoelectric generator (TEG) produces electricity when the temperature differential is applied across the TEG. This article reports a precision method in characterizing TEG modules. A precision instrument is constructed to study thermoelectric conversion in terms of output power and efficiency of TEG modules. The maximum allowable TEG module size is 150 mm, and the preferred size is from 30 mm to 60 mm. During measurements, the highest hot side temperature is 500 °C and the cold side temperature can be adjusted from room temperature to 100 °C. A mechanical structure is developed to control the pressure and parallelism of the clamping force of the TEG on both its hot and cold sides. A heat flux measurement module is installed at its cold side, and the heat flux through TEGs can be measured in position. Finally, the energy conversion efficiency of TEGs is calculated from experimental data of both an output power and a heat flux.

Computational evaluation of amplitude modulation for enhanced magnetic nanoparticle hyperthermia.

PubMed

Soetaert, Frederik; Dupré, Luc; Ivkov, Robert; Crevecoeur, Guillaume

2015-10-01

Magnetic nanoparticles (MNPs) can interact with alternating magnetic fields (AMFs) to deposit localized energy for hyperthermia treatment of cancer. Hyperthermia is useful in the context of multimodality treatments with radiation or chemotherapy to enhance disease control without increased toxicity. The unique attributes of heat deposition and transfer with MNPs have generated considerable attention and have been the focus of extensive investigations to elucidate mechanisms and optimize performance. Three-dimensional (3D) simulations are often conducted with the finite element method (FEM) using the Pennes' bioheat equation. In the current study, the Pennes' equation was modified to include a thermal damage-dependent perfusion profile to improve model predictions with respect to known physiological responses to tissue heating. A normal distribution of MNPs in a model liver tumor was combined with empirical nanoparticle heating data to calculate tumor temperature distributions and resulting survival fraction of cancer cells. In addition, calculated spatiotemporal temperature changes were compared among magnetic field amplitude modulations of a base 150-kHz sinusoidal waveform, specifically, no modulation, sinusoidal, rectangular, and triangular modulation. Complex relationships were observed between nanoparticle heating and cancer tissue damage when amplitude modulation and damage-related perfusion profiles were varied. These results are tantalizing and motivate further exploration of amplitude modulation as a means to enhance efficiency of and overcome technical challenges associated with magnetic nanoparticle hyperthermia (MNH).

Optimized Heat Pipe Backup Cooling System Tested with a Stirling Convertor

NASA Technical Reports Server (NTRS)

Schwendeman, Carl L.; Tarau, Calin; Schifer, Nicholas A.; Anderson, William G.; Garner, Scott

2016-01-01

In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal variable conductance heat pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor by bypassing the heat during stops. In a previous NASA Small Business Innovation Research (SBIR) Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for the Stirling RPS. In 2012, one of these VCHPs was successfully tested at NASA Glenn Research Center with a Stirling convertor as an Advanced Stirling Radioisotope Generator (ASRG) backup cooling system. The prototype; however, was not optimized and did not reflect the final heat rejection path. ACT through further funding has developed a semioptimized prototype with the finalized heat path for testing at Glenn with a Stirling convertor. The semioptimized system features a two-phase radiator and is significantly smaller and lighter than the prior prototype to reflect a higher level of flight readiness. The VCHP is designed to activate and remove heat from the GPHS during stoppage with a small temperature increase from the nominal vapor temperature. This small temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the multilayer insulation (MLI). The VCHP passively allows the Stirling convertor to be turned off multiple times during a mission with potentially unlimited off durations. Having the ability to turn the Stirling off allows for the Stirling to be reset and reduces vibrations on the platform during sensitive measurements or procedures. This paper presents the design of the VCHP and its test results with a Stirling convertor at Glenn. Tests were carried for multiple on and off cycles to demonstrate repeatability. The impacts associated with the addition of the VCHP to the system are also addressed in terms of mass and additional heat losses due to the presence of the VCHP.

Thermal and other tests of photovoltaic modules performed in natural sunlight

NASA Technical Reports Server (NTRS)

Stultz, J. W.

1978-01-01

The bulk of the testing was the characterization of twenty-nine modules according to their nominal operating cell temperature (NOCT) and the effect on NOCT of changes in module design, various residential roof mounting configurations, and dirt accumulation. Other tests, often performed parallel with the NOCT measurements, evaluated the improvement in electrical performance by cooling the modules with water and by channeling the waste heat into a phase change material (wax). Electrical degradation resulting from the natural marriage of photovoltaic and solar water heating modules was also demonstrated. Cost effectiveness of each of these techniques are evaluated in light of the LSA cost goal of $0.50 per watt.

Scaling behavior of the thermal conductivity of width-modulated nanowires and nanofilms for heat transfer control at the nanoscale.

PubMed

Zianni, Xanthippi; Jean, Valentin; Termentzidis, Konstantinos; Lacroix, David

2014-11-21

We report on scaling behavior of the thermal conductivity of width-modulated nanowires and nanofilms that have been studied with the phonon Monte Carlo technique. It has been found that the reduction of the thermal conductivity scales with the nanostructure transmissivity, a property entirely determined by the modulation geometry, irrespectively of the material choice. Tuning of the thermal conductivity is possible by the nanostructure width-modulation without strict limitations for the modulation profile. In addition, a very significant constriction thermal resistance due to width-discontinuity has been identified, in analogy to the contact thermal resistance between two dissimilar materials. The constriction thermal resistance also scales with the modulated nanostructure transmissivity. Our conclusions are generic indicating that a wide range of materials can be used for the modulated nanostructures. Direct heat flow control can be provided by designing the nanostructure width-modulation.

Carbothermic reduction with parallel heat sources

DOEpatents

Troup, Robert L.; Stevenson, David T.

1984-12-04

Disclosed are apparatus and method of carbothermic direct reduction for producing an aluminum alloy from a raw material mix including aluminum oxide, silicon oxide, and carbon wherein parallel heat sources are provided by a combustion heat source and by an electrical heat source at essentially the same position in the reactor, e.g., such as at the same horizontal level in the path of a gravity-fed moving bed in a vertical reactor. The present invention includes providing at least 79% of the heat energy required in the process by the electrical heat source.

Loop Heat Pipe Operation Using Heat Source Temperature for Set Point Control

NASA Technical Reports Server (NTRS)

Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

2011-01-01

Loop heat pipes (LHPs) have been used for thermal control of several NASA and commercial orbiting spacecraft. The LHP operating temperature is governed by the saturation temperature of its compensation chamber (CC). Most LHPs use the CC temperature for feedback control of its operating temperature. There exists a thermal resistance between the heat source to be cooled by the LHP and the LHP's CC. Even if the CC set point temperature is controlled precisely, the heat source temperature will still vary with its heat output. For most applications, controlling the heat source temperature is of most interest. A logical question to ask is: "Can the heat source temperature be used for feedback control of the LHP operation?" A test program has been implemented to answer the above question. Objective is to investigate the LHP performance using the CC temperature and the heat source temperature for feedback control

Versatile Desktop Experiment Module (DEMo) on Heat Transfer

ERIC Educational Resources Information Center

Minerick, Adrienne R.

2010-01-01

This paper outlines a new Desktop Experiment Module (DEMo) engineered for a chemical engineering junior-level Heat Transfer course. This new DEMo learning tool is versatile, fairly inexpensive, and portable such that it can be positioned on student desks throughout a classroom. The DEMo system can illustrate conduction of various materials,…

Obtaining Heat Stress Measurements. Module 15. Vocational Education Training in Environmental Health Sciences.

ERIC Educational Resources Information Center

Consumer Dynamics Inc., Rockville, MD.

This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on obtaining heat stress measurements. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming and describing the…

Orion Service Module Reaction Control System Plume Impingement Analysis Using PLIMP/RAMP2

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen; Lumpkin, Forrest E., III; Gati, Frank; Yuko, James R.; Motil, Brian J.

2009-01-01

The Orion Crew Exploration Vehicle Service Module Reaction Control System engine plume impingement was computed using the plume impingement program (PLIMP). PLIMP uses the plume solution from RAMP2, which is the refined version of the reacting and multiphase program (RAMP) code. The heating rate and pressure (force and moment) on surfaces or components of the Service Module were computed. The RAMP2 solution of the flow field inside the engine and the plume was compared with those computed using GASP, a computational fluid dynamics code, showing reasonable agreement. The computed heating rate and pressure using PLIMP were compared with the Reaction Control System plume model (RPM) solution and the plume impingement dynamics (PIDYN) solution. RPM uses the GASP-based plume solution, whereas PIDYN uses the SCARF plume solution. Three sets of the heating rate and pressure solutions agree well. Further thermal analysis on the avionic ring of the Service Module was performed using MSC Patran/Pthermal. The obtained temperature results showed that thermal protection is necessary because of significant heating from the plume.

Hydride compressor

DOEpatents

Powell, James R.; Salzano, Francis J.

1978-01-01

Method of producing high energy pressurized gas working fluid power from a low energy, low temperature heat source, wherein the compression energy is gained by using the low energy heat source to desorb hydrogen gas from a metal hydride bed and the desorbed hydrogen for producing power is recycled to the bed, where it is re-adsorbed, with the recycling being powered by the low energy heat source. In one embodiment, the adsorption-desorption cycle provides a chemical compressor that is powered by the low energy heat source, and the compressor is connected to a regenerative gas turbine having a high energy, high temperature heat source with the recycling being powered by the low energy heat source.

Dual source heat pump

DOEpatents

Ecker, Amir L.; Pietsch, Joseph A.

1982-01-01

What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid provides energy for defrosting the second heat exchanger when operating in the air source mode and also provides a alternate source of heat.

Excitation of earth-ionosphere waveguide in the ELF and lower VLF bands by modulated ionospheric current. Technical report

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

Field, E.C.; Bloom, R.M.

1993-05-21

In this report the authors use the principal of reciprocity in conjunction with a full-wave propagation code to calculate ground-level fields excited by ionospheric currents modulated at frequencies between 50 and 100 Hz with HF heaters. Their results show the dependence on source orientation, altitude, and dimension and therefore pertain to experiments using the HIPAS or HAARP ionospheric heaters. In the end-fire mode, the waveguide excitation efficiency of an ELF HED in the ionosphere is up to 20 dB greater than for a ground-based antenna, provided its altitude does not exceed 80-to-90 km. The highest efficiency occurs for a sourcemore » altitude of around 70 km; if that altitude is raised to 100 km, the efficiency drops by about 20 dB in the day and 10 dB at night. That efficiency does not account for the greater conductivity modulation that might be achieved at altitudes greater than 70 km, however. The trade-off between the altitude dependencies of the excitation efficiency and maximum achievable modulation depends on the ERP of the HF heater, the optimum altitude increasing with increasing ERP. For HIPAS the best modulation altitude is around 70 km, whereas for HAARP there might be marginal value in modulating at attitudes as high as 100 Km. Ionospheric modification, Ionospheric currents, Ionospheric heating.« less

30 CFR 56.4500 - Heat sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Heat sources. 56.4500 Section 56.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 56.4500 Heat sources. Heat sources capable of producing combustion...

30 CFR 57.4500 - Heat sources.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Heat sources. 57.4500 Section 57.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 57.4500 Heat sources. Heat sources capable of producing combustion...

30 CFR 57.4500 - Heat sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Heat sources. 57.4500 Section 57.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 57.4500 Heat sources. Heat sources capable of producing combustion...

30 CFR 57.4500 - Heat sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Heat sources. 57.4500 Section 57.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 57.4500 Heat sources. Heat sources capable of producing combustion...

30 CFR 56.4500 - Heat sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Heat sources. 56.4500 Section 56.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 56.4500 Heat sources. Heat sources capable of producing combustion...

30 CFR 56.4500 - Heat sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Heat sources. 56.4500 Section 56.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 56.4500 Heat sources. Heat sources capable of producing combustion...

30 CFR 57.4500 - Heat sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Heat sources. 57.4500 Section 57.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 57.4500 Heat sources. Heat sources capable of producing combustion...

30 CFR 56.4500 - Heat sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Heat sources. 56.4500 Section 56.4500 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Installation/construction/maintenance § 56.4500 Heat sources. Heat sources capable of producing combustion...

Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

NASA Technical Reports Server (NTRS)

Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

2013-01-01

In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 C temperature increase from the nominal vapor temperature. The 19 C temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental results from integrating the VCHP with an operating Stirling convertor and describes the methodology used to achieve their successful combined operation.

Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

NASA Technical Reports Server (NTRS)

Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

2013-01-01

In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 degC temperature increase from the nominal vapor temperature. The 19 degC temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental results from integrating the VCHP with an operating Stirling convertor and describes the methodology used to achieve their successful combined operation.

Passive rejection of heat from an isotope heat source through an open door

NASA Technical Reports Server (NTRS)

Burns, R. K.

1971-01-01

The isotope heat-source design for a Brayton power system includes a door in the thermal insulation through which the heat can be passively rejected to space when the power system is not operating. The results of an analysis to predict the heat-source surface temperature and the heat-source heat-exchanger temperature during passive heat rejection as a function of insulation door opening angle are presented. They show that for a door opening angle greater than 20 deg, the temperatures are less than the steady-state temperatures during power system operation.

Mini-Brayton heat source assembly design study. Volume 2: Titan 3C mission. [minimum weight modifications

NASA Technical Reports Server (NTRS)

1973-01-01

Major conclusions of the space shuttle heat source assembly study are reported that project a minimum weight design for a Titan 3 C synchronous orbit mission; requirements to recover the heat source in orbit are eliminated. This concept permits location of the heat source end enclosure supports and heat source assembly support housing in a low temperature region external to the insulation enclosure and considers titanium and beryllium alloys for these support elements. A high melting insulation blanket consisting of nickel foil coated with zirconia, or of gold foil separated with glass fiber layers, is selected to provide emergency cooling in the range 2000 to 2700 F to prevent the isotope heat source from reaching unsafe temperatures. A graphic view of the baseline heat source assembly is included.

Regenerable non-venting cooler for protective suit

NASA Technical Reports Server (NTRS)

Roebelen, Jr., George J. (Inventor); Bayes, Stephen A. (Inventor)

1992-01-01

A life support back pack 14 for use during extravehicular activity in space incorporates a cooling apparatus 20 comprised of five panels 22 each of which include in layered fashion a LCG coolant heat exchange coil 32, a heat distribution plate 42, and a heat dissipation module 50A or 50B having an outer radiator surface 52. Each module 50A houses a first phase change material 55A, for example hexadecane paraffin, and each module 50B houses a second phase change material 55B, for example tetradecane paraffin, which has a phase change temperature which is less than the phase change temperature of the first phase change material 55A. The cooling apparatus 20 is equipped with a coolant heat exchange circuit provided with mode selection valves 84 and 86 which are operated by a controller 88 to selectively direct the LCG coolant to be cooled through the cooling apparatus in one of three operating modes.

Reconstruction of high temporal resolution Thomson scattering data during a modulated electron cyclotron resonance heating using conditional averaging

NASA Astrophysics Data System (ADS)

Kobayashi, T.; Ida, K.; Itoh, K.; Yoshinuma, M.; Moon, C.; Inagaki, S.; Yamada, I.; Funaba, H.; Yasuhara, R.; Tsuchiya, H.; Ohdachi, S.; Yoshimura, Y.; Igami, H.; Shimozuma, T.; Kubo, S.; Tsujimura, T. I.

2016-04-01

This paper provides a software application of the sampling scope concept for fusion research. The time evolution of Thomson scattering data is reconstructed with a high temporal resolution during a modulated electron cyclotron resonance heating (MECH) phase. The amplitude profile and the delay time profile of the heat pulse propagation are obtained from the reconstructed signal for discharges having on-axis and off-axis MECH depositions. The results are found to be consistent with the MECH deposition.

A User-Friendly Software Package for HIFU Simulation

NASA Astrophysics Data System (ADS)

Soneson, Joshua E.

2009-04-01

A freely-distributed, MATLAB (The Mathworks, Inc., Natick, MA)-based software package for simulating axisymmetric high-intensity focused ultrasound (HIFU) beams and their heating effects is discussed. The package (HIFU_Simulator) consists of a propagation module which solves the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation and a heating module which solves Pennes' bioheat transfer (BHT) equation. The pressure, intensity, heating rate, temperature, and thermal dose fields are computed, plotted, the output is released to the MATLAB workspace for further user analysis or postprocessing.

Thermoelectric generator for motor vehicle

DOEpatents

Bass, John C.

1997-04-29

A thermoelectric generator for producing electric power for a motor vehicle from the heat of the exhaust gasses produced by the engine of the motor vehicle. The exhaust gasses pass through a finned heat transfer support structure which has seat positions on its outside surface for the positioning of thermoelectric modules. A good contact cylinder provides a framework from which a spring force can be applied to the thermoelectric modules to hold them in good contact on their seats on the surface of the heat transfer support structure.

Reconstruction of high temporal resolution Thomson scattering data during a modulated electron cyclotron resonance heating using conditional averaging

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

Kobayashi, T., E-mail: kobayashi.tatsuya@LHD.nifs.ac.jp; Yoshinuma, M.; Ohdachi, S.

2016-04-15

This paper provides a software application of the sampling scope concept for fusion research. The time evolution of Thomson scattering data is reconstructed with a high temporal resolution during a modulated electron cyclotron resonance heating (MECH) phase. The amplitude profile and the delay time profile of the heat pulse propagation are obtained from the reconstructed signal for discharges having on-axis and off-axis MECH depositions. The results are found to be consistent with the MECH deposition.

Reconstruction of high temporal resolution Thomson scattering data during a modulated electron cyclotron resonance heating using conditional averaging.

PubMed

Kobayashi, T; Ida, K; Itoh, K; Yoshinuma, M; Moon, C; Inagaki, S; Yamada, I; Funaba, H; Yasuhara, R; Tsuchiya, H; Ohdachi, S; Yoshimura, Y; Igami, H; Shimozuma, T; Kubo, S; Tsujimura, T I

2016-04-01

This paper provides a software application of the sampling scope concept for fusion research. The time evolution of Thomson scattering data is reconstructed with a high temporal resolution during a modulated electron cyclotron resonance heating (MECH) phase. The amplitude profile and the delay time profile of the heat pulse propagation are obtained from the reconstructed signal for discharges having on-axis and off-axis MECH depositions. The results are found to be consistent with the MECH deposition.

Progress towards an Optimization Methodology for Combustion-Driven Portable Thermoelectric Power Generation Systems

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

Krishnan, Shankar; Karri, Naveen K.; Gogna, Pawan K.

2012-03-13

Enormous military and commercial interests exist in developing quiet, lightweight, and compact thermoelectric (TE) power generation systems. This paper investigates design integration and analysis of an advanced TE power generation system implementing JP-8 fueled combustion and thermal recuperation. Design and development of a portable TE power system using a JP-8 combustor as a high temperature heat source and optimal process flows depend on efficient heat generation, transfer, and recovery within the system are explored. Design optimization of the system required considering the combustion system efficiency and TE conversion efficiency simultaneously. The combustor performance and TE sub-system performance were coupled directlymore » through exhaust temperatures, fuel and air mass flow rates, heat exchanger performance, subsequent hot-side temperatures, and cold-side cooling techniques and temperatures. Systematic investigation of this system relied on accurate thermodynamic modeling of complex, high-temperature combustion processes concomitantly with detailed thermoelectric converter thermal/mechanical modeling. To this end, this work reports on design integration of systemlevel process flow simulations using commercial software CHEMCADTM with in-house thermoelectric converter and module optimization, and heat exchanger analyses using COMSOLTM software. High-performance, high-temperature TE materials and segmented TE element designs are incorporated in coupled design analyses to achieve predicted TE subsystem level conversion efficiencies exceeding 10%. These TE advances are integrated with a high performance microtechnology combustion reactor based on recent advances at the Pacific Northwest National Laboratory (PNNL). Predictions from this coupled simulation established a basis for optimal selection of fuel and air flow rates, thermoelectric module design and operating conditions, and microtechnology heat-exchanger design criteria. This paper will discuss this simulation process that leads directly to system efficiency power maps defining potentially available optimal system operating conditions and regimes. This coupled simulation approach enables pathways for integrated use of high-performance combustor components, high performance TE devices, and microtechnologies to produce a compact, lightweight, combustion driven TE power system prototype that operates on common fuels.« less

Studies on the temperature distribution of a thick film transcutaneous oxygen sensor and its thermal influences on oxygen measurement.

PubMed

Lam, Liza; Bilek, Jaromir; Atkinson, John

2006-11-01

The partial pressures of gases, namely oxygen and carbon dioxide, in the arterial blood are important parameters for doctors to determine the respiratory conditions of patients. Currently in practice, there are a number of ways to measure these parameters, one of which is transcutaneous blood gas monitoring. This technique is a popular noninvasive measurement method for obtaining fast and relatively accurate responses. In this investigation, thick film technology has been employed to develop an amperometric oxygen sensor which consists of a heating module to elevate the temperature at the skin surface to transcutaneous levels. The heating module includes a heating element and its temperature is regulated by a temperature control circuit. Using an infrared camera, the transient and steady-state temperature distributions as well as the stability of the heating element have been analysed. The influence of temperature on the oxygen sensing module is also studied. In addition, a three-dimensional theoretical model is established to evaluate the thermal response of the sensor and subsequently compared with the results from the practical prototype. With this model, the design stages can be simplified and future heating modules for transcutaneous sensors could be generated and improved more easily and effectively.

Heat Shock Partially Dissociates the Overlapping Modules of the Yeast Protein-Protein Interaction Network: A Systems Level Model of Adaptation

PubMed Central

Mihalik, Ágoston; Csermely, Peter

2011-01-01

Network analysis became a powerful tool giving new insights to the understanding of cellular behavior. Heat shock, the archetype of stress responses, is a well-characterized and simple model of cellular dynamics. S. cerevisiae is an appropriate model organism, since both its protein-protein interaction network (interactome) and stress response at the gene expression level have been well characterized. However, the analysis of the reorganization of the yeast interactome during stress has not been investigated yet. We calculated the changes of the interaction-weights of the yeast interactome from the changes of mRNA expression levels upon heat shock. The major finding of our study is that heat shock induced a significant decrease in both the overlaps and connections of yeast interactome modules. In agreement with this the weighted diameter of the yeast interactome had a 4.9-fold increase in heat shock. Several key proteins of the heat shock response became centers of heat shock-induced local communities, as well as bridges providing a residual connection of modules after heat shock. The observed changes resemble to a ‘stratus-cumulus’ type transition of the interactome structure, since the unstressed yeast interactome had a globally connected organization, similar to that of stratus clouds, whereas the heat shocked interactome had a multifocal organization, similar to that of cumulus clouds. Our results showed that heat shock induces a partial disintegration of the global organization of the yeast interactome. This change may be rather general occurring in many types of stresses. Moreover, other complex systems, such as single proteins, social networks and ecosystems may also decrease their inter-modular links, thus develop more compact modules, and display a partial disintegration of their global structure in the initial phase of crisis. Thus, our work may provide a model of a general, system-level adaptation mechanism to environmental changes. PMID:22022244

A RADIATION TRANSFER SOLVER FOR ATHENA USING SHORT CHARACTERISTICS

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

Davis, Shane W.; Stone, James M.; Jiang Yanfei

2012-03-01

We describe the implementation of a module for the Athena magnetohydrodynamics (MHD) code that solves the time-independent, multi-frequency radiative transfer (RT) equation on multidimensional Cartesian simulation domains, including scattering and non-local thermodynamic equilibrium (LTE) effects. The module is based on well known and well tested algorithms developed for modeling stellar atmospheres, including the method of short characteristics to solve the RT equation, accelerated Lambda iteration to handle scattering and non-LTE effects, and parallelization via domain decomposition. The module serves several purposes: it can be used to generate spectra and images, to compute a variable Eddington tensor (VET) for full radiationmore » MHD simulations, and to calculate the heating and cooling source terms in the MHD equations in flows where radiation pressure is small compared with gas pressure. For the latter case, the module is combined with the standard MHD integrators using operator splitting: we describe this approach in detail, including a new constraint on the time step for stability due to radiation diffusion modes. Implementation of the VET method for radiation pressure dominated flows is described in a companion paper. We present results from a suite of test problems for both the RT solver itself and for dynamical problems that include radiative heating and cooling. These tests demonstrate that the radiative transfer solution is accurate and confirm that the operator split method is stable, convergent, and efficient for problems of interest. We demonstrate there is no need to adopt ad hoc assumptions of questionable accuracy to solve RT problems in concert with MHD: the computational cost for our general-purpose module for simple (e.g., LTE gray) problems can be comparable to or less than a single time step of Athena's MHD integrators, and only few times more expensive than that for more general (non-LTE) problems.« less

Updated neutronics analyses of a water cooled ceramic breeder blanket for the CFETR

NASA Astrophysics Data System (ADS)

Xiaokang, ZHANG; Songlin, LIU; Xia, LI; Qingjun, ZHU; Jia, LI

2017-11-01

The water cooled ceramic breeder (WCCB) blanket employing pressurized water as a coolant is one of the breeding blanket candidates for the China Fusion Engineering Test Reactor (CFETR). Some updating of neutronics analyses was needed, because there were changes in the neutronics performance of the blanket as several significant modifications and improvements have been adopted for the WCCB blanket, including the optimization of radial build-up and customized structure for each blanket module. A 22.5 degree toroidal symmetrical torus sector 3D neutronics model containing the updated design of the WCCB blanket modules was developed for the neutronics analyses. The tritium breeding capability, nuclear heating power, radiation damage, and decay heat were calculated by the MCNP and FISPACT code. The results show that the packing factor and 6Li enrichment of the breeder should both be no less than 0.8 to ensure tritium self-sufficiency. The nuclear heating power of the blanket under 200 MW fusion power reaches 201.23 MW. The displacement per atom per full power year (FPY) of the plasma-facing component and first wall reach 0.90 and 2.60, respectively. The peak H production rate reaches 150.79 appm/FPY and the peak He production reaches 29.09 appm/FPY in blanket module #3. The total decay heat of the blanket modules is 2.64 MW at 1 s after shutdown and the average decay heat density can reach 11.09 kW m-3 at that time. The decay heat density of the blanket modules slowly decreases to lower than 10 W m-3 in more than ten years.

Combining CFD simulations with blockoriented heatflow-network model for prediction of photovoltaic energy-production

NASA Astrophysics Data System (ADS)

Haber, I. E.; Farkas, I.

2011-01-01

The exterior factors which influencing the working circumstances of photovoltaic modules are the irradiation, the optical air layer (Air Mass - AM), the irradiation angle, the environmental temperature and the cooling effect of the wind. The efficiency of photovoltaic (PV) devices is inversely proportional to the cell temperature and therefore the mounting of the PV modules can have a big affect on the cooling, due to wind flow-around and naturally convection. The construction of the modules could be described by a heatflow-network model, and that can define the equation which determines the cells temperature. An equation like this can be solved as a block oriented model with hybrid-analogue simulator such as Matlab-Simulink. In view of the flow field and the heat transfer, witch was calculated numerically, the heat transfer coefficients can be determined. Five inflow rates were set up for both pitched and flat roof cases, to let the trend of the heat transfer coefficient know, while these functions can be used for the Matlab/Simulink model. To model the free convection flows, the Boussinesq-approximation were used, integrated into the Navier-Stokes equations and the energy equation. It has been found that under a constant solar heat gain, the air velocity around the modules and behind the pitched-roof mounted module is increasing, proportionately to the wind velocities, and as result the heat transfer coefficient increases linearly, and can be described by a function in both cases. To the block based model the meteorological parameters and the results of the CFD simulations as single functions were attached. The final aim was to make a model that could be used for planning photovoltaic systems, and define their accurate performance for better sizing of an array of modules.

Dynamical and statistical phenomena of circulation and heat transfer in periodically forced rotating turbulent Rayleigh-Bénard convection

NASA Astrophysics Data System (ADS)

Sterl, Sebastian; Li, Hui-Min; Zhong, Jin-Qiang

2016-12-01

In this paper, we present results from an experimental study into turbulent Rayleigh-Bénard convection forced externally by periodically modulated unidirectional rotation rates. We find that the azimuthal rotation velocity θ ˙(t ) and thermal amplitude δ (t ) of the large-scale circulation (LSC) are modulated by the forcing, exhibiting a variety of dynamics including increasing phase delays and a resonant peak in the amplitude of θ ˙(t ) . We also focus on the influence of modulated rotation rates on the frequency of occurrence η of stochastic cessation or reorientation events, and on the interplay between such events and the periodically modulated response of θ ˙(t ) . Here we identify a mechanism by which η can be amplified by the modulated response, and these normally stochastic events can occur with high regularity. We provide a modeling framework that explains the observed amplitude and phase responses, and we extend this approach to make predictions for the occurrence of cessation events and the probability distributions of θ ˙(t ) and δ (t ) during different phases of a modulation cycle, based on an adiabatic approach that treats each phase separately. Last, we show that such periodic forcing has consequences beyond influencing LSC dynamics, by investigating how it can modify the heat transport even under conditions where the Ekman pumping effect is predominant and strong enhancement of heat transport occurs. We identify phase and amplitude responses of the heat transport, and we show how increased modulations influence the average Nusselt number.

Scanning thermal probe microscope method for the determination of thermal diffusivity of nanocomposite thin films

NASA Astrophysics Data System (ADS)

Varandani, Deepak; Agarwal, Khushboo; Brugger, Juergen; Mehta, Bodh Raj

2016-08-01

A commercial scanning thermal microscope has been upgraded to facilitate its use in estimating the radial thermal diffusivity of thin films close to room temperature. The modified setup includes a microcontroller driven microhotplate coupled with a Bluetooth module for wireless control. The microcontroller board (Arduino Leonardo) is used to generate a bias of suitable voltage amplitude and pulse duration which is applied across the microhotplate contact pads. A corresponding heat pulse from the Pt heating element (1 mm2) embedded within the microhotplate is delivered to the lower surface of the thin film (25 mm2) deposited over it. The large difference in the dimensions of the heating source and the thin film surface causes heat to flow radially outwards on the top surface of the latter. The decay of this radial heat wave as it flows outwards is recorded by the scanning thermal microscope in terms of temperature-time (T-t) profiles at varying positions around the central heating zone. A fitting procedure is suggested to extract the thermal diffusivity value from the array of T-t profiles. The efficacy of the above setup has been established by evaluating the thermal diffusivities of Bi2Te3 and Bi2Te3:Si thin film samples. Further, with only minor alterations in design the capabilities of the above setup can be extended to estimate the axial thermal diffusivity and specific heat of thin films, as a function of temperature.

Thermal Interface Evaluation of Heat Transfer from a Pumped Loop to Titanium-Water Thermosyphons

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.; Sanzi, James L.; Gibson, Marc A.; Sechkar, Edward A.

2009-01-01

Titanium-water thermosyphons are being considered for use in the heat rejection system for lunar outpost fission surface power. Key to their use is heat transfer between a closed loop heat source and the heat pipe evaporators. This work describes laboratory testing of several interfaces that were evaluated for their thermal performance characteristics, in the temperature range of 350 to 400 K, utilizing a water closed loop heat source and multiple thermosyphon evaporator geometries. A gas gap calorimeter was used to measure heat flow at steady state. Thermocouples in the closed loop heat source and on the evaporator were used to measure thermal conductance. The interfaces were in two generic categories, those immersed in the water closed loop heat source and those clamped to the water closed loop heat source with differing thermal conductive agents. In general, immersed evaporators showed better overall performance than their clamped counterparts. Selected clamped evaporator geometries offered promise.

Safe atmosphere entry of an isotope heat source with a single stable trim attitude at hypersonic speeds

NASA Technical Reports Server (NTRS)

Levy, L. L., Jr.; Burns, R. K.

1972-01-01

A theoretical investigation has been made to design an isotope heat source capable of satisfying the conflicting thermal requirements of steady-state operation and atmosphere entry. The isotope heat source must transfer heat efficiently to a heat exchange during normal operation with a power system in space, and in the event of a mission abort, it must survive the thermal environment of atmosphere entry and ground impact without releasing radioactive material. A successful design requires a compatible integration of the internal components of the heat source with the external aerodynamic shape. To this end, configurational, aerodynamic, motion, and thermal analyses were coupled and iterated during atmosphere entries at suborbital through superorbital velocities at very shallow and very steep entry angles. Results indicate that both thermal requirements can be satisfied by a heat source which has a single stable aerodynamic orientation at hypersonic speeds. For such a design, the insulation material required to adequately protect the isotope fuel from entry heating need extend only half way around the fuel capsule on the aerodynamically stable (wind-ward) side of the heat source. Thus, a low-thermal-resistance, conducting heat path is provided on the opposite side of the heat source through which heat can be transferred to an adjacent heat exchanger during normal operation without exceeding specified temperature limits.

The Arabidopsis polyamine transporter LHR1/PUT3 modulates heat responsive gene expression by enhancing mRNA stability.

PubMed

Shen, Yun; Ruan, Qingxia; Chai, Haoxi; Yuan, Yongze; Yang, Wannian; Chen, Junping; Xin, Zhanguo; Shi, Huazhong

2016-12-01

Polyamines involve in gene regulation by interacting with and modulating the functions of various anionic macromolecules such as DNA, RNA and proteins. In this study, we identified an important function of the polyamine transporter LHR1 (LOWER EXPRESSION OF HEAT RESPONSIVE GENE1) in heat-inducible gene expression in Arabidopsis thaliana. The lhr1 mutant was isolated through a forward genetic screening for altered expression of the luciferase reporter gene driven by the promoter from the heat-inducible gene AtHSP18.2. The lhr1 mutant showed reduced induction of the luciferase gene in response to heat stress and was more sensitive to high temperature than the wild type. Map-based cloning identified that the LHR1 gene encodes the polyamine transporter PUT3 (POLYAMINE UPTAKE TRANSPORTER 3) localized in the plasma membrane. The LHR1/PUT3 is required for the uptake of extracellular polyamines and plays an important role in stabilizing the mRNAs of several crucial heat stress responsive genes under high temperature. Genome-wide gene expression analysis using RNA-seq identified an array of differentially expressed genes, among which the transcript levels of some of the heat shock protein genes significantly reduced in response to prolonged heat stress in the lhr1 mutant. Our findings revealed an important heat stress response and tolerance mechanism involving polyamine influx which modulates mRNA stability of heat-inducible genes under heat stress conditions. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Geothermal Energy: Resource and Utilization. A Teaching Module.

ERIC Educational Resources Information Center

Nguyen, Van Thanh

The search for new energy resources as alternatives to fossil fuels have generated new interest in the heat of the earth itself. New geothermal areas with a variety of characteristics are being explored, as are new ways of extracting work from naturally heated steam and hot water. Some of this effort is discussed in this three-part module. Five…

The Power Transistor: A Module on Heat Transfer. Tech Physics Series.

ERIC Educational Resources Information Center

Technical Education Research Center, Cambridge, MA.

This module is intended to provide an understanding of the principles related to heat transfer. The objectives are designed to enable the learner to select and install a device for measuring the temperature of a power transistor, determine power ratings, measure the transient response for a power level and its final equilibrium temperature. Other…

Integrated exhaust and electrically heated particulate filter regeneration systems

DOEpatents

Gonze, Eugene V.; Paratore, Jr., Michael J.

2013-01-08

A system includes a particulate matter (PM) filter that includes multiple zones. An electrical heater includes heater segments that are associated with respective ones of the zones. The electrical heater is arranged upstream from and proximate with the PM filter. A post-fuel injection system injects fuel into at least one of a cylinder of an engine and an exhaust system. A control module is configured to operate in a first mode that includes activating the electrical heater to heat exhaust of the engine. The control module is also configured to operate in a second mode that includes activating the post-injection system to heat the exhaust. The control module selectively operates in at least one of the first mode and the second mode.

Self-contained heat rejection module for future spacecraft

NASA Technical Reports Server (NTRS)

Fleming, M. L.; Williams, J. L.; Baskett, J. D.; Leach, J. W.

1975-01-01

This paper discusses development of a Self-Contained Heat Rejection Module (SHRM) which can be used on a wide variety of future spacecraft launched by the space shuttle orbiter. The SHRM contains radiators which are deployed by a scissor-mechanism and the flow equipment including pumps, accumulator, by-pass valves, and controllers necessary to reject heat from those radiators. Heat transfer between SHRM and the parent vehicle is effected by a contact heat exchanger. This device provides heat transfer between two separate flow loops through a mechanical connection. This approach reduces the time required to attach the SHRM to the payload, and increases the reliability of the SHRM flow loop since breaking into the fluid system in the field is not required. The SHRM concept also includes a refrigeration system to increase heat rejection capacity in adverse environments, or to provide for a lower return temperature, down to -23 C.

Dynamic Modulation of Radiative Heat Transfer beyond the Blackbody Limit.

PubMed

Ito, Kota; Nishikawa, Kazutaka; Miura, Atsushi; Toshiyoshi, Hiroshi; Iizuka, Hideo

2017-07-12

Dynamic control of electromagnetic heat transfer without changing mechanical configuration opens possibilities in intelligent thermal management in nanoscale systems. We confirmed by experiment that the radiative heat transfer is dynamically modulated beyond the blackbody limit. The near-field electromagnetic heat exchange mediated by phonon-polariton is controlled by the metal-insulator transition of tungsten-doped vanadium dioxide. The functionalized heat flux is transferred over an area of 1.6 cm 2 across a 370 nm gap, which is maintained by the microfabricated spacers and applied pressure. The uniformity of the gap is validated by optical interferometry, and the measured heat transfer is well modeled as the sum of the radiative and the parasitic conductive components. The presented methodology to form a nanometric gap with functional heat flux paves the way to the smart thermal management in various scenes ranging from highly integrated systems to macroscopic apparatus.

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

21 CFR 872.6475 - Heat source for bleaching teeth.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Heat source for bleaching teeth. 872.6475 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6475 Heat source for bleaching teeth. (a) Identification. A heat source for bleaching teeth is an AC-powered device that consists of a...

A capital cost comparison of commercial ground-source heat pump systems

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

Rafferty, K.

1994-06-01

The purpose of the report is to compare capital costs associated with the three designs of ground source heat pumps. Specifically, the costs considered are those associated with the heat source/heat sink or ground source portion of the system. In order to standardize the heat rejection over the three designs, it was assumed that the heat pump loop would operate at a temperature range of 85{degree} (to the heat pumps) to 95{degree} (from the heat pumps) under peak conditions. The assumption of constant loop temperature conditions for all three permits an apples-to-apples comparison of the alternatives.

Integrated optical transceiver with electronically controlled optical beamsteering

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

Davids, Paul; DeRose, Christopher; Tauke-Pedretti, Anna

A beam-steering optical transceiver is provided. The transceiver includes one or more modules, each comprising an antenna chip and a control chip bonded to the antenna chip. Each antenna chip has a feeder waveguide, a plurality of row waveguides that tap off from the feeder waveguide, and a plurality of metallic nanoantenna elements arranged in a two-dimensional array of rows and columns such that each row overlies one of the row waveguides. Each antenna chip also includes a plurality of independently addressable thermo-optical phase shifters, each configured to produce a thermo-optical phase shift in a respective row. Each antenna chipmore » also has, for each row, a row-wise heating circuit configured to produce a respective thermo-optic phase shift at each nanoantenna element along its row. The control chip includes controllable current sources for the independently addressable thermo-optical phase shifters and the row-wise heating circuits.« less

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

Fan, Jiwen; Rosenfeld, Daniel; Zhang, Yuwei

Aerosol-cloud interaction remains the largest uncertainty in climate projections. Ultrafine aerosol particles (UAP; size <50nm) are considered too small to serve as cloud condensation nuclei conventionally. However, this study provides observational evidence to accompany insights from numerical simulations to support that deep convective clouds (DCCs) over Amazon have strong capability of nucleating UAP from an urban source and forming greater numbers of droplets, because fast drop coalescence in these DCCs reduces drop surface area available for condensation, leading to high vapor supersaturation. The additional droplets subsequently decrease supersaturation and release more condensational latent heating, a dominant contributor to convection intensification,more » whereas enhanced latent heat from ice-related processes plays a secondary role. Therefore, the addition of anthropogenic UAP may play a much greater role in modulating clouds than previously believed over the Amazon region and possibly in other relatively pristine regions such as maritime and forest locations.« less

Computer modeling of thermoelectric generator performance

NASA Technical Reports Server (NTRS)

Chmielewski, A. B.; Shields, V.

1982-01-01

Features of the DEGRA 2 computer code for simulating the operations of a spacecraft thermoelectric generator are described. The code models the physical processes occurring during operation. Input variables include the thermoelectric couple geometry and composition, the thermoelectric materials' properties, interfaces and insulation in the thermopile, the heat source characteristics, mission trajectory, and generator electrical requirements. Time steps can be specified and sublimation of the leg and hot shoe is accounted for, as are shorts between legs. Calculations are performed for conduction, Peltier, Thomson, and Joule heating, the cold junction can be adjusted for solar radition, and the legs of the thermoelectric couple are segmented to enhance the approximation accuracy. A trial run covering 18 couple modules yielded data with 0.3% accuracy with regard to test data. The model has been successful with selenide materials, SiGe, and SiN4, with output of all critical operational variables.

An ion source module for the Beijing Radioactive Ion-beam Facility

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

Cui, B., E-mail: cui@ciae.ac.cn; Huang, Q.; Tang, B.

2014-02-15

An ion source module is developed for Beijing Radioactive Ion-beam Facility. The ion source module is designed to meet the requirements of remote handling. The connection and disconnection of the electricity, cooling and vacuum between the module and peripheral units can be executed without on-site manual work. The primary test of the target ion source has been carried out and a Li{sup +} beam has been extracted. Details of the ion source module and its primary test results are described.

Flexible, FEP-Teflon covered solar cell module development

NASA Technical Reports Server (NTRS)

Rauschenbach, H. S.; Cannady, M. D.

1976-01-01

Techniques and equipment were developed for the large scale, low-cost fabrication of lightweight, roll-up and fold-up, FEP-Teflon encapsulated solar cell modules. Modules were fabricated by interconnecting solderless single-crystal silicon solar cells and heat laminating them at approximately 300 C between layers of optically clear FEP and to a loadbearing Kapton substrate sheet. Modules were fabricated from both conventional and wraparound contact solar cells. A heat seal technique was developed for mechanically interconnecting modules into an array. The electrical interconnections for both roll-up and fold-up arrays were also developed. The use of parallel-gap resistance welding, ultrasonic bonding, and thermocompression bonding processes for attaching interconnects to solar cells were investigated. Parallel-gap welding was found to be best suited for interconnecting the solderless solar cells into modules. Details of the fabrication equipment, fabrication processes, module and interconnect designs, environmental test equipment, and test results are presented.

Microwave Imaging with Infrared 2-D Lock-in Amplifier

NASA Astrophysics Data System (ADS)

Chiyo, Noritaka; Arai, Mizuki; Tanaka, Yasuhiro; Nishikata, Atsuhiro; Maeno, Takashi

We have developed a 3-D electromagnetic field measurement system using 2-D lock-in amplifier. This system uses an amplitude modulated electromagnetic wave source to heat a resistive screen. A very small change of temperature on a screen illuminated with the modulated electromagnetic wave is measured using an infrared thermograph camera. In this paper, we attempted to apply our system to microwave imaging. By placing conductor patches in front of the resistive screen and illuminating with microwave, the shape of each conductor was clearly observed as the temperature difference image of the screen. In this way, the conductor pattern inside the non-contact type IC card could be visualized. Moreover, we could observe the temperature difference image reflecting the shape of a Konnyaku (a gelatinous food made from devil's-tonge starch) or a dried fishbone, both as non-conducting material resembling human body. These results proved that our method is applicable to microwave see-through imaging.

Modulated electron cyclotron drift instability in a high-power pulsed magnetron discharge.

PubMed

Tsikata, Sedina; Minea, Tiberiu

2015-05-08

The electron cyclotron drift instability, implicated in electron heating and anomalous transport, is detected in the plasma of a planar magnetron. Electron density fluctuations associated with the mode are identified via an adapted coherent Thomson scattering diagnostic, under direct current and high-power pulsed magnetron operation. Time-resolved analysis of the mode amplitude reveals that the instability, found at MHz frequencies and millimeter scales, also exhibits a kHz-scale modulation consistent with the observation of larger-scale plasma density nonuniformities, such as the rotating spoke. Sharply collimated axial fluctuations observed at the magnetron axis are consistent with the presence of escaping electrons in a region where the magnetic and electric fields are antiparallel. These results distinguish aspects of magnetron physics from other plasma sources of similar geometry, such as the Hall thruster, and broaden the scope of instabilities which may be considered to dictate magnetron plasma features.

Thermal analysis of a conceptual design for a 250 We GPHS/FPSE space power system

NASA Technical Reports Server (NTRS)

Mccomas, Thomas J.; Dugan, Edward T.

1991-01-01

A thermal analysis has been performed for a 250-We space nuclear power system which combines the US Department of Energy's general purpose heat source (GPHS) modules with a state-of-the-art free-piston Stirling engine (FPSE). The focus of the analysis is on the temperature of the indium fuel clad within the GPHS modules. The thermal analysis results indicate fuel clad temperatures slightly higher than the design goal temperature of 1573 K. The results are considered favorable due to numerous conservative assumptions used. To demonstrate the effects of the conservatism, a brief sensitivity analysis is performed in which a few of the key system parameters are varied to determine their effect on the fuel clad temperatures. It is shown that thermal analysis of a more detailed thermal mode should yield fuel clad temperatures below 1573 K.

Maisotsenko cycle applications in multi-stage ejector recycling module for chemical production

NASA Astrophysics Data System (ADS)

Levchenko, D. O.; Artyukhov, A. E.; Yurko, I. V.

2017-08-01

The article is devoted to the theoretical bases of multistage (multi-level) utilization modules as part of chemical plants (on the example of the technological line for obtaining nitrogen fertilizers). The possibility of recycling production waste (ammonia vapors, dust and substandard nitrogen fertilizers) using ejection devices and waste heat using Maisotsenko cycle technology (Maisotsenko heat and mass exchanger (HMX), Maisotsenko power cycles and recuperators, etc.) is substantiated. The principle of operation of studied recycling module and prospects for its implementation are presented. An improved technological scheme for obtaining granular fertilizers and granules with porous structure with multistage (multi-level) recycling module is proposed.

Handling Nonlinearities in ELF/VLF Generation Using Modulated Heating at HAARP

NASA Astrophysics Data System (ADS)

Jin, G.; Spasojevic, M.; Cohen, M.; Inan, U. S.

2011-12-01

George Jin Maria Spasojevic Morris Cohen Umran Inan Stanford University Modulated HF heating of the D-region ionosphere near the auroral electrojet can generate extremely low frequency (ELF) waves in the kilohertz range. This process is nonlinear and generates harmonics at integer multiples of the ELF modulation frequency. The nonlinear distortion has implications for any communications applications since the harmonics contain a substantial fraction of the signal power and use up bandwidth. We examine two techniques for handling the nonlinearity. First we modulate the HF heating with a non-sinusoidal envelope designed to create a sinusoidal change in the Hall conductivity at a particular altitude in the ionosphere to minimize any generated harmonics. The modulation waveform is generated by inverting a numerical HF heating model, starting from the desired conductivity time series, and obtaining the HF power envelope that will result in that conductivity. The second technique attempts to use the energy in the harmonics to improve bit error rates when digital modulation is applied to the ELF carrier. In conventional quadrature phase-shift keying (QPSK), where a ELF carrier is phase-shifted by 0°, 90°, 180°, and 270° in order to transmit a pair of bits, the even harmonics cannot distinguish between the four possible shifts. By using different phase values, all the energy in the harmonics can contribute to determining the phase of the carrier and thus improve the bit error rate.

Dry coolers and air-condensing units (Review)

NASA Astrophysics Data System (ADS)

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

2016-03-01

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

Evaluation of the heat transfer module (FAHT) of Failure Analysis Nonlinear Thermal And Structural Integrated Code (FANTASTIC)

NASA Technical Reports Server (NTRS)

Keyhani, Majid

1989-01-01

The heat transfer module of FANTASTIC Code (FAHT) is studied and evaluated to the extend possible during the ten weeks duration of this project. A brief background of the previous studies is given and the governing equations as modeled in FAHT are discussed. FAHT's capabilities and limitations based on these equations and its coding methodology are explained in detail. It is established that with improper choice of element size and time step FAHT's temperature field prediction at some nodes will be below the initial condition. The source of this unrealistic temperature prediction is identified and a procedure is proposed for avoiding this phenomenon. It is further shown that the proposed procedure will converge to an accurate prediction upon mesh refinement. Unfortunately due to lack of time FAHT's ability to accurately account for pyrolysis and surface ablation has not been verified. Therefore, at the present time it can be stated with confidence that FAHT can accurately predict the temperature field for a transient multi-dimensional, orthotropic material with directional dependence, variable property, with nonlinear boundary condition. Such a prediction will provide an upper limit for the temperature field in an ablating decomposing nozzle liner. The pore pressure field, however, will not be known.

Frequency swept microwaves for hyperfine decoupling and time domain dynamic nuclear polarization

PubMed Central

Hoff, Daniel E.M.; Albert, Brice J.; Saliba, Edward P.; Scott, Faith J.; Choi, Eric J.; Mardini, Michael; Barnes, Alexander B.

2015-01-01

Hyperfine decoupling and pulsed dynamic nuclear polarization (DNP) are promising techniques to improve high field DNP NMR. We explore experimental and theoretical considerations to implement them with magic angle spinning (MAS). Microwave field simulations using the high frequency structural simulator (HFSS) software suite are performed to characterize the inhomogeneous phase independent microwave field throughout a 198 GHz MAS DNP probe. Our calculations show that a microwave power input of 17 W is required to generate an average EPR nutation frequency of 0.84 MHz. We also present a detailed calculation of microwave heating from the HFSS parameters and find that 7.1% of the incident microwave power contributes to dielectric sample heating. Voltage tunable gyrotron oscillators are proposed as a class of frequency agile microwave sources to generate microwave frequency sweeps required for the frequency modulated cross effect, electron spin inversions, and hyperfine decoupling. Electron spin inversions of stable organic radicals are simulated with SPINEVOLUTION using the inhomogeneous microwave fields calculated by HFSS. We calculate an electron spin inversion efficiency of 56% at a spinning frequency of 5 kHz. Finally, we demonstrate gyrotron acceleration potentials required to generate swept microwave frequency profiles for the frequency modulated cross effect and electron spin inversions. PMID:26482131

Thermally multiplexed polymerase chain reaction.

PubMed

Phaneuf, Christopher R; Pak, Nikita; Saunders, D Curtis; Holst, Gregory L; Birjiniuk, Joav; Nagpal, Nikita; Culpepper, Stephen; Popler, Emily; Shane, Andi L; Jerris, Robert; Forest, Craig R

2015-07-01

Amplification of multiple unique genetic targets using the polymerase chain reaction (PCR) is commonly required in molecular biology laboratories. Such reactions are typically performed either serially or by multiplex PCR. Serial reactions are time consuming, and multiplex PCR, while powerful and widely used, can be prone to amplification bias, PCR drift, and primer-primer interactions. We present a new thermocycling method, termed thermal multiplexing, in which a single heat source is uniformly distributed and selectively modulated for independent temperature control of an array of PCR reactions. Thermal multiplexing allows amplification of multiple targets simultaneously-each reaction segregated and performed at optimal conditions. We demonstrate the method using a microfluidic system consisting of an infrared laser thermocycler, a polymer microchip featuring 1 μl, oil-encapsulated reactions, and closed-loop pulse-width modulation control. Heat transfer modeling is used to characterize thermal performance limitations of the system. We validate the model and perform two reactions simultaneously with widely varying annealing temperatures (48 °C and 68 °C), demonstrating excellent amplification. In addition, to demonstrate microfluidic infrared PCR using clinical specimens, we successfully amplified and detected both influenza A and B from human nasopharyngeal swabs. Thermal multiplexing is scalable and applicable to challenges such as pathogen detection where patients presenting non-specific symptoms need to be efficiently screened across a viral or bacterial panel.

Frequency swept microwaves for hyperfine decoupling and time domain dynamic nuclear polarization.

PubMed

Hoff, Daniel E M; Albert, Brice J; Saliba, Edward P; Scott, Faith J; Choi, Eric J; Mardini, Michael; Barnes, Alexander B

2015-11-01

Hyperfine decoupling and pulsed dynamic nuclear polarization (DNP) are promising techniques to improve high field DNP NMR. We explore experimental and theoretical considerations to implement them with magic angle spinning (MAS). Microwave field simulations using the high frequency structural simulator (HFSS) software suite are performed to characterize the inhomogeneous phase independent microwave field throughout a 198GHz MAS DNP probe. Our calculations show that a microwave power input of 17W is required to generate an average EPR nutation frequency of 0.84MHz. We also present a detailed calculation of microwave heating from the HFSS parameters and find that 7.1% of the incident microwave power contributes to dielectric sample heating. Voltage tunable gyrotron oscillators are proposed as a class of frequency agile microwave sources to generate microwave frequency sweeps required for the frequency modulated cross effect, electron spin inversions, and hyperfine decoupling. Electron spin inversions of stable organic radicals are simulated with SPINEVOLUTION using the inhomogeneous microwave fields calculated by HFSS. We calculate an electron spin inversion efficiency of 56% at a spinning frequency of 5kHz. Finally, we demonstrate gyrotron acceleration potentials required to generate swept microwave frequency profiles for the frequency modulated cross effect and electron spin inversions. Copyright © 2015 Elsevier Inc. All rights reserved.

Inductively heated particulate matter filter regeneration control system

DOEpatents

Gonze, Eugene V; Paratore Jr., Michael J; Kirby, Kevin W; Phelps, Amanda; Gregoire, Daniel J

2012-10-23

A system includes a particulate matter (PM) filter with an upstream end for receiving exhaust gas, a downstream end and zones. The system also includes a heating element. A control module selectively activates the heating element to inductively heat one of the zones.

Generation and Upper Atmospheric Propagation of Acoustic Gravity Waves according to Numerical Modeling and Radio Tomography

NASA Astrophysics Data System (ADS)

Vorontsov, Artem; Andreeva, Elena; Nesterov, Ivan; Padokhin, Artem; Kurbatov, Grigory

2016-04-01

The acoustic-gravity waves (AGW) in the upper atmosphere and ionosphere can be generated by a variety of the phenomena in the near-Earth environment and atmosphere as well as by some perturbations of the Earth's ground or ocean surface. For instance, the role of the AGW sources can be played by the earthquakes, explosions, thermal heating, seisches, tsunami waves. We present the examples of AGWs excited by the tsunami waves traveling in the ocean, by seisches, and by ionospheric heating by the high-power radio wave. In the last case, the gravity waves are caused by the pulsed modulation of the heating wave. The AGW propagation in the upper atmosphere induces the variations and irregularities in the electron density distribution of the ionosphere, whose structure can be efficiently reconstructed by the method of the ionospheric radio tomography (RT) based on the data from the global navigational satellite systems (GNSS). The input data for RT diagnostics are composed of the 150/400 MHz radio signals from the low-orbiting (LO) satellites and 1.2-1.5 GHz radio signals from the high-orbiting (HO) satellites with their orbits at ~1000 and ~20000 km above the ground, respectively. These data enable ionospheric imaging on different spatiotemporal scales with different spatiotemporal resolution and coverage, which is suitable, inter alia, for tracking the waves and wave-like features in the ionosphere. In particular, we demonstrate the maps of the ionospheric responses to the tornado at Moore (Oklahoma, USA) of May 20, 2013, which are reconstructed from the HO data. We present the examples of LORT images containing the waves and wavelike disturbances associated with various sources (e.g., auroral precipitation and high-power heating of the ionosphere). We also discuss the results of modeling the AGW generation by the surface and volumetric sources. The millihertz AGW from these sources initiate the ionospheric perturbation with a typical scale of a few hundred km at the heights corresponding to the middle atmosphere and ionosphere. The results of numerical modeling based on the solution of the equation of geophysical hydrodynamics agree with the observations.

Minimal universal quantum heat machine.

PubMed

Gelbwaser-Klimovsky, D; Alicki, R; Kurizki, G

2013-01-01

In traditional thermodynamics the Carnot cycle yields the ideal performance bound of heat engines and refrigerators. We propose and analyze a minimal model of a heat machine that can play a similar role in quantum regimes. The minimal model consists of a single two-level system with periodically modulated energy splitting that is permanently, weakly, coupled to two spectrally separated heat baths at different temperatures. The equation of motion allows us to compute the stationary power and heat currents in the machine consistent with the second law of thermodynamics. This dual-purpose machine can act as either an engine or a refrigerator (heat pump) depending on the modulation rate. In both modes of operation, the maximal Carnot efficiency is reached at zero power. We study the conditions for finite-time optimal performance for several variants of the model. Possible realizations of the model are discussed.

Nanoscale phase engineering of thermal transport with a Josephson heat modulator.

PubMed

Fornieri, Antonio; Blanc, Christophe; Bosisio, Riccardo; D'Ambrosio, Sophie; Giazotto, Francesco

2016-03-01

Macroscopic quantum phase coherence has one of its pivotal expressions in the Josephson effect, which manifests itself both in charge and energy transport. The ability to master the amount of heat transferred through two tunnel-coupled superconductors by tuning their phase difference is the core of coherent caloritronics, and is expected to be a key tool in a number of nanoscience fields, including solid-state cooling, thermal isolation, radiation detection, quantum information and thermal logic. Here, we show the realization of the first balanced Josephson heat modulator designed to offer full control at the nanoscale over the phase-coherent component of thermal currents. Our device provides magnetic-flux-dependent temperature modulations up to 40 mK in amplitude with a maximum of the flux-to-temperature transfer coefficient reaching 200 mK per flux quantum at a bath temperature of 25 mK. Foremost, it demonstrates the exact correspondence in the phase engineering of charge and heat currents, breaking ground for advanced caloritronic nanodevices such as thermal splitters, heat pumps and time-dependent electronic engines.

Thermal buffering of receivers for parabolic dish solar thermal power plants

NASA Technical Reports Server (NTRS)

Manvi, R.; Fujita, T.; Gajanana, B. C.; Marcus, C. J.

1980-01-01

A parabolic dish solar thermal power plant comprises a field of parabolic dish power modules where each module is composed of a two-axis tracking parabolic dish concentrator which reflects sunlight (insolation) into the aperture of a cavity receiver at the focal point of the dish. The heat generated by the solar flux entering the receiver is removed by a heat transfer fluid. In the dish power module, this heat is used to drive a small heat engine/generator assembly which is directly connected to the cavity receiver at the focal point. A computer analysis is performed to assess the thermal buffering characteristics of receivers containing sensible and latent heat thermal energy storage. Parametric variations of the thermal inertia of the integrated receiver-buffer storage systems coupled with different fluid flow rate control strategies are carried out to delineate the effect of buffer storage, the transient response of the receiver-storage systems and corresponding fluid outlet temperature. It is concluded that addition of phase change buffer storage will substantially improve system operational characteristics during periods of rapidly fluctuating insolation due to cloud passage.

Nanoscale phase engineering of thermal transport with a Josephson heat modulator

NASA Astrophysics Data System (ADS)

Fornieri, Antonio; Blanc, Christophe; Bosisio, Riccardo; D'Ambrosio, Sophie; Giazotto, Francesco

2016-03-01

Macroscopic quantum phase coherence has one of its pivotal expressions in the Josephson effect, which manifests itself both in charge and energy transport. The ability to master the amount of heat transferred through two tunnel-coupled superconductors by tuning their phase difference is the core of coherent caloritronics, and is expected to be a key tool in a number of nanoscience fields, including solid-state cooling, thermal isolation, radiation detection, quantum information and thermal logic. Here, we show the realization of the first balanced Josephson heat modulator designed to offer full control at the nanoscale over the phase-coherent component of thermal currents. Our device provides magnetic-flux-dependent temperature modulations up to 40 mK in amplitude with a maximum of the flux-to-temperature transfer coefficient reaching 200 mK per flux quantum at a bath temperature of 25 mK. Foremost, it demonstrates the exact correspondence in the phase engineering of charge and heat currents, breaking ground for advanced caloritronic nanodevices such as thermal splitters, heat pumps and time-dependent electronic engines.

Solar Thermoelectricity via Advanced Latent Heat Storage

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

Olsen, Michele L.; Rea, J.; Glatzmaier, Greg C.

2016-05-31

We report on a new modular, dispatchable, and cost-effective solar electricity-generating technology. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) integrates several state-of-the-art technologies to provide electricity on demand. In the envisioned STEALS system, concentrated sunlight is converted to heat at a solar absorber. The heat is then delivered to either a thermoelectric (TE) module for direct electricity generation, or to charge a phase change material for thermal energy storage, enabling subsequent generation during off-sun hours, or both for simultaneous electricity production and energy storage. The key to making STEALS a dispatchable technology lies in the development of a 'thermalmore » valve,' which controls when heat is allowed to flow through the TE module, thus controlling when electricity is generated. The current project addresses each of the three major subcomponents, (i) the TE module, (ii) the thermal energy storage system, and (iii) the thermal valve. The project also includes system-level and techno- economic modeling of the envisioned integrated system and will culminate in the demonstration of a laboratory-scale STEALS prototype capable of generating 3kWe.« less

Solar thermoelectricity via advanced latent heat storage

NASA Astrophysics Data System (ADS)

Olsen, M. L.; Rea, J.; Glatzmaier, G. C.; Hardin, C.; Oshman, C.; Vaughn, J.; Roark, T.; Raade, J. W.; Bradshaw, R. W.; Sharp, J.; Avery, A. D.; Bobela, D.; Bonner, R.; Weigand, R.; Campo, D.; Parilla, P. A.; Siegel, N. P.; Toberer, E. S.; Ginley, D. S.

2016-05-01

We report on a new modular, dispatchable, and cost-effective solar electricity-generating technology. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) integrates several state-of-the-art technologies to provide electricity on demand. In the envisioned STEALS system, concentrated sunlight is converted to heat at a solar absorber. The heat is then delivered to either a thermoelectric (TE) module for direct electricity generation, or to charge a phase change material for thermal energy storage, enabling subsequent generation during off-sun hours, or both for simultaneous electricity production and energy storage. The key to making STEALS a dispatchable technology lies in the development of a "thermal valve," which controls when heat is allowed to flow through the TE module, thus controlling when electricity is generated. The current project addresses each of the three major subcomponents, (i) the TE module, (ii) the thermal energy storage system, and (iii) the thermal valve. The project also includes system-level and techno- economic modeling of the envisioned integrated system and will culminate in the demonstration of a laboratory-scale STEALS prototype capable of generating 3kWe.

Selective chemical detection by energy modulation of sensors

DOEpatents

Stetter, J.R.; Otagawa, T.

1985-05-20

A portable instrument for use in the field in detecting, identifying, and quantifying a component of a sampled fluid includes a sensor which chemically reacts with the component of interest or a derivative thereof, an electrical heating filament for heating the sample before it is applied to the sensor, and modulating means for continuously varying the temperature of the filament (and hence the reaction rate) between two values sufficient to produce the chemical reaction. In response to this thermal modulation, the sensor produces a modulated output signal, the modulation of which is a function of the activation energy of the chemical reaction, which activation energy is specific to the particular component of interest and its concentration. Microprocessor means compares the modulated output signal with standard responses for a plurality of components to identify and quantify the particular component of interest. 4 figs.

Optics-based approach to thermal management of photovoltaics: Selective-spectral and radiative cooling

DOE PAGES

Sun, Xingshu; Silverman, Timothy J.; Zhou, Zhiguang; ...

2017-01-20

For commercial one-sun solar modules, up to 80% of the incoming sunlight may be dissipated as heat, potentially raising the temperature 20-30 °C higher than the ambient. In the long term, extreme self-heating erodes efficiency and shortens lifetime, thereby dramatically reducing the total energy output. Therefore, it is critically important to develop effective and practical (and preferably passive) cooling methods to reduce operating temperature of photovoltaic (PV) modules. In this paper, we explore two fundamental (but often overlooked) origins of PV self-heating, namely, sub-bandgap absorption and imperfect thermal radiation. The analysis suggests that we redesign the optical properties of themore » solar module to eliminate parasitic absorption (selective-spectral cooling) and enhance thermal emission (radiative cooling). Comprehensive opto-electro-thermal simulation shows that the proposed techniques would cool one-sun terrestrial solar modules up to 10 °C. As a result, this self-cooling would substantially extend the lifetime for solar modules, with corresponding increase in energy yields and reduced levelized cost of electricity.« less

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.

Recommended OSC design and analysis of AMTEC power system for outer-planet missions

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

Schock, A.; Noravian, H.; Or, C.

1999-01-01

The paper describes OSC designs and analyses of AMTEC cells and radioisotope power systems for possible application to NASA{close_quote}s Europa Orbiter and Pluto Kuiper Express missions, and compares their predicted performance with JPL{close_quote}s preliminary mission goals. The latest cell and generator designs presented here were the culmination of studies covering a wide variety of generator configurations and operating parameters. The many steps and rationale leading to OSC{close_quote}s design evolution and materials selection were discussed in earlier publications and will not be repeated here except for a description of OSC{close_quote}s latest design, including a recent heat source support scheme and cellmore » configuration that have not been described in previous publications. As shown, that heat source support scheme eliminates all contact between the heat source and the AMTEC (Alkali Metal Thermal-to-Electrical Conversion) cells, which simplifies the generator{close_quote}s structural design as well as its fabrication and assembly procedure. An additional purpose of the paper is to describe a revised cell design and fabrication procedure which represent a major departure from previous OSC designs. Previous cells had a uniform diameter, but in the revised design the cell wall beyond the BASE tubes has a greatly reduced diameter. The paper presents analytical performance predictions which show that the revised ({open_quotes}chimney{close_quotes}) cell design yields substantially higher efficiencies than the previous (cylindrical) design. This makes it possible to meet and substantially exceed the JPL-stipulated EOM power goal with four instead of six General Purpose Heat Source (GPHS) modules, resulting in a one-third reduction in the heat source mass, cost, and fuel requirements. OSC{close_quote}s performance predictions were based on its techniques for the coupled thermal, electrical, and fluid flow analyses of AMTEC generators. Those analytical techniques have been partially validated by tests of prototypic test assemblies designed by OSC, built by AMPS, and tested by AFRL. The analytical results indicate that the OSC power system design, operating within the stipulated evaporator and clad temperature limits and well within its mass goals, can yield EOM power outputs and system efficiencies that substantially exceed the JPL-specified goals for the Europa and Pluto missions. However, those results only account for radioisotope decay. Other degradation mechanisms are still under study, and their short-and long-term effects must be quantified and understood before final conclusions about the adequacy and competitiveness of the AMTEC system can be drawn. {copyright} {ital 1999 American Institute of Physics.}« less

Manufacturing development for the SAFE 100 kW core

NASA Astrophysics Data System (ADS)

Carter, Robert; Roman, Jose; Salvail, Pat

2002-01-01

In stark contrast to what is sometimes considered the norm in traditional manufacturing processes, engineers at the Marshall Space Flight Center (MSFC) arc in the practice of altering the standard in an effort to realize other potential methods in core manufacturing. While remaining within the bounds of the materials database, we are researching into core manufacturing techniques that may have been overlooked in the past due to funding and/or time constraints. To augment proven core fabrication capabilities we are pursuing plating processes as another possible method for core build-up and assembly. Although brazing and a proprietary HIP cycle are used for module assembly (proven track record for stability and endurance), it is prudent to pursue secondary or backup methods of module and core assembly. For this reason heat tube manufacture and module assembly by means of plating is being investigated. Potentially, the plating processes will give engineers the ability to manufacture replacement modules for any module that might fail to perform nominally, and to assemble/disassemble a complete core in much less time than would be required for the conventional Braze-HIP process. Another area of improvement in core manufacturing capabilities is the installation of a sodium and lithium liquid metal heat pipe fill machine. This, along with the ability to Electron Beam Weld heat pipe seals and wet-in the pipes in the necessary vacuum atmosphere, will eliminate the need to ship potentially hazardous components outside for processing. In addition to developing core manufacturing techniques, the SAFE manufacturing team has been evaluating the thermal heat transfer characteristics, and manufacturability of several heat exchanger design concepts. .

Heat pump system

DOEpatents

Swenson, Paul F.; Moore, Paul B.

1979-01-01

An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchangers and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.

Heat pump system

DOEpatents

Swenson, Paul F.; Moore, Paul B.

1982-01-01

An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchanges and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.

Pervaporation process and assembly

DOEpatents

Wynn, Nicholas P.; Huang, Yu; Aldajani, Tiem; Fulton, Donald A.

2010-07-20

The invention is a pervaporation process and pervaporation equipment, using a series of membrane modules, and including inter-module reheating of the feed solution under treatment. The inter-module heating is achieved within the tube or vessel in which the modules are housed, thereby avoiding the need to repeatedly extract the feed solution from the membrane module train.

Pervaporation assembly

DOEpatents

Wynn, Nicholas P [Redwood City, CA; Huang, Yu [Palo Alto, CA; Aldajani, Tiem [San Jose, CA; Fulton, Donald A [Fairfield, CA

2012-02-28

The invention is a pervaporation process and pervaporation equipment, using a series of membrane modules, and including inter-module reheating of the feed solution under treatment. The inter-module heating is achieved within the tube or vessel in which the modules are housed, thereby avoiding the need to repeatedly extract the feed solution from the membrane module train.

Power-Stepped HF Cross Modulation Experiments at HAARP

NASA Astrophysics Data System (ADS)

Greene, S.; Moore, R. C.; Langston, J. S.

2013-12-01

High frequency (HF) cross modulation experiments are a well established means for probing the HF-modified characteristics of the D-region ionosphere. In this paper, we apply experimental observations of HF cross-modulation to the related problem of ELF/VLF wave generation. HF cross-modulation measurements are used to evaluate the efficiency of ionospheric conductivity modulation during power-stepped modulated HF heating experiments. The results are compared to previously published dependencies of ELF/VLF wave amplitude on HF peak power. The experiments were performed during the March 2013 campaign at the High Frequency Active Auroral Research Program (HAARP) Observatory. HAARP was operated in a dual-beam transmission format: the first beam heated the ionosphere using sinusoidal amplitude modulation while the second beam broadcast a series of low-power probe pulses. The peak power of the modulating beam was incremented in 1-dB steps. We compare the minimum and maximum cross-modulation effect and the amplitude of the resulting cross-modulation waveform to the expected power-law dependence of ELF/VLF wave amplitude on HF power.

Heat source reconstruction from noisy temperature fields using an optimised derivative Gaussian filter

NASA Astrophysics Data System (ADS)

Delpueyo, D.; Balandraud, X.; Grédiac, M.

2013-09-01

The aim of this paper is to present a post-processing technique based on a derivative Gaussian filter to reconstruct heat source fields from temperature fields measured by infrared thermography. Heat sources can be deduced from temperature variations thanks to the heat diffusion equation. Filtering and differentiating are key-issues which are closely related here because the temperature fields which are processed are unavoidably noisy. We focus here only on the diffusion term because it is the most difficult term to estimate in the procedure, the reason being that it involves spatial second derivatives (a Laplacian for isotropic materials). This quantity can be reasonably estimated using a convolution of the temperature variation fields with second derivatives of a Gaussian function. The study is first based on synthetic temperature variation fields corrupted by added noise. The filter is optimised in order to reconstruct at best the heat source fields. The influence of both the dimension and the level of a localised heat source is discussed. Obtained results are also compared with another type of processing based on an averaging filter. The second part of this study presents an application to experimental temperature fields measured with an infrared camera on a thin plate in aluminium alloy. Heat sources are generated with an electric heating patch glued on the specimen surface. Heat source fields reconstructed from measured temperature fields are compared with the imposed heat sources. Obtained results illustrate the relevancy of the derivative Gaussian filter to reliably extract heat sources from noisy temperature fields for the experimental thermomechanics of materials.

Heat Balance of a Sheep in the Sun. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

ERIC Educational Resources Information Center

Hatheway, W. H.

These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. Specifically, this module develops a method for calculating the exchange of heat between an…

Electrically heated particulate filter diagnostic systems and methods

DOEpatents

Gonze, Eugene V [Pinckney, MI

2009-09-29

A system that diagnoses regeneration of an electrically heated particulate filter is provided. The system generally includes a grid module that diagnoses a fault of the grid based on at least one of a current signal and a voltage signal. A diagnostic module at least one of sets a fault status and generates a warning signal based on the fault of the grid.

Solar heating and cooling system design and development

NASA Technical Reports Server (NTRS)

1978-01-01

Application surveys and performance studies were conducted to determine a solar heating and hot water configuration that could be used in a variety of applications, and to identify subsystem modules that could be utilized in a building block fashion to adapt hardware items to single and multi-family residential and commercial systems. Topics discussed include: subsystem development for the solar collectors, controls, other components, energy management module, and the heating system configuration test. Operational tests conducted at an Illinois farmhouse, and a YWCA in Spokane, Washington are discussed.

Boeing CST-100 Starliner Base Heat Shield Installation

NASA Image and Video Library

2018-03-15

On March 15, the base heat shield for Boeing’s CST-100 Starliner was freshly installed on the bottom of Spacecraft 1 in the High Bay of the Commercial Crew and Cargo Processing Facility at Kennedy Space Center. This is the spacecraft that will fly during the Pad Abort Test. The next step involves installation of the back shells and forward heat shield, and then the crew module will be mated to the service module for a fit check. Finally, the vehicle will head out to White Sands Missile Range in New Mexico for testing.

Using Paraffin PCM to Make Optical Communication Type of Payloads Thermally Self-Sufficient for Operation in Orion Crew Module

NASA Technical Reports Server (NTRS)

Choi, Michael K.

2016-01-01

An innovative concept of using paraffin phase change material with a melting point of 28 C to make Optical Communication type of payload thermally self-sufficient for operation in the Orion Crew Module is presented. It stores the waste heat of the payload and permits it to operate for about one hour by maintaining its temperature within the maximum operating limit. It overcomes the problem of relying on the availability of cold plate heat sink in the Orion Crew Module.

Inverted Three-Junction Tandem Thermophotovoltaic Modules

NASA Technical Reports Server (NTRS)

Wojtczuk, Steven

2012-01-01

An InGaAs-based three-junction (3J) tandem thermophotovoltaic (TPV) cell has been investigated to utilize more of the blackbody spectrum (from a 1,100 C general purpose heat source GPHS) efficiently. The tandem consists of three vertically stacked subcells, a 0.74-eV InGaAs cell, a 0.6- eV InGaAs cell, and a 0.55-eV InGaAs cell, as well as two interconnecting tunnel junctions. A greater than 20% TPV system efficiency was achieved by another group with a 1,040 C blackbody using a single-bandgap 0.6- eV InGaAs cell MIM (monolithic interconnected module) (30 lateral junctions) that delivered about 12 V/30 or 0.4 V/junction. It is expected that a three-bandgap tandem MIM will eventually have about 3 this voltage (1.15 V) and about half the current. A 4 A/cm2 would be generated by a single-bandgap 0.6-V InGaAs MIM, as opposed to the 2 A/cm2 available from the same spectrum when split among the three series-connected junctions in the tandem stack. This would then be about a 50% increase (3xVoc, 0.5xIsc) in output power if the proposed tandem replaced the single- bandgap MIM. The advantage of the innovation, if successful, would be a 50% increase in power conversion efficiency from radioisotope heat sources using existing thermophotovoltaics. Up to 50% more power would be generated for radioisotope GPHS deep space missions. This type of InGaAs multijunction stack could be used with terrestrial concentrator solar cells to increase efficiency from 41 to 45% or more.

Multi-Purpose Logistics Module (MPLM) Cargo Heat Exchanger

NASA Technical Reports Server (NTRS)

Zampiceni, John J.; Harper, Lon T.

2002-01-01

This paper describes the New Shuttle Orbiter's Multi- Purpose Logistics Modulo (MPLM) Cargo Heat Exchanger (HX) and associated MPLM cooling system. This paper presents Heat Exchanger (HX) design and performance characteristics of the system.

Silicon Heat Pipe Array

NASA Technical Reports Server (NTRS)

Yee, Karl Y.; Ganapathi, Gani B.; Sunada, Eric T.; Bae, Youngsam; Miller, Jennifer R.; Beinsford, Daniel F.

2013-01-01

Improved methods of heat dissipation are required for modern, high-power density electronic systems. As increased functionality is progressively compacted into decreasing volumes, this need will be exacerbated. High-performance chip power is predicted to increase monotonically and rapidly with time. Systems utilizing these chips are currently reliant upon decades of old cooling technology. Heat pipes offer a solution to this problem. Heat pipes are passive, self-contained, two-phase heat dissipation devices. Heat conducted into the device through a wick structure converts the working fluid into a vapor, which then releases the heat via condensation after being transported away from the heat source. Heat pipes have high thermal conductivities, are inexpensive, and have been utilized in previous space missions. However, the cylindrical geometry of commercial heat pipes is a poor fit to the planar geometries of microelectronic assemblies, the copper that commercial heat pipes are typically constructed of is a poor CTE (coefficient of thermal expansion) match to the semiconductor die utilized in these assemblies, and the functionality and reliability of heat pipes in general is strongly dependent on the orientation of the assembly with respect to the gravity vector. What is needed is a planar, semiconductor-based heat pipe array that can be used for cooling of generic MCM (multichip module) assemblies that can also function in all orientations. Such a structure would not only have applications in the cooling of space electronics, but would have commercial applications as well (e.g. cooling of microprocessors and high-power laser diodes). This technology is an improvement over existing heat pipe designs due to the finer porosity of the wick, which enhances capillary pumping pressure, resulting in greater effective thermal conductivity and performance in any orientation with respect to the gravity vector. In addition, it is constructed of silicon, and thus is better suited for the cooling of semiconductor devices.

Remote sensing of mesospheric dust layers using active modulation of PMWE by high-power radio-waves

NASA Astrophysics Data System (ADS)

Cohen, M.; Zhang, X.; Cohen, M.; Mahmoudian, A.; Scales, W.; Kosch, M. J.; M Farahani, M.; Mohebalhojeh, A.

2016-12-01

So-called polar mesospheric winter echoes (PMWE) are radar echoes observed during winter at altitudes around 50-80 km and are much weaker than their PMSE (Polar Mesospheric Summer Echoes) counterpart. Unlike PMSE, PMWE are less studied and understood. Breaking of gravity waves and the associated turbulence are proposed as the major source for PMWE echoes. The action of neutral turbulence alone does not appear to give a good explanation for PMWE. PMWE is also attributed to Bragg scatter from electron irregularities which result from charging of free electrons onto sub-visible particles. The temporal behavior of PMWE response to HF pump heating can be employed to diagnose the charged dust layer. Specifically, the rise and fall time of radar echo strength as well as relaxation and recovery time after heater turn-on and off are distinct parameters that are a function of radar frequency. This work presents the first study of the modulation of PMWE by artificial radiowave heating using computational modeling and experimental observation in different radar frequency bands. Variation of dust plasma parameters associated with PMWE such as dust radius, dust density, recombination rate, electron- and dust-neutral collision frequencies, photo-detachment current and electron temperature enhancement ratio are included. Computational results derived from different sets of parameters are considered and compared with recent observations at EISCAT using 224 MHz and 56 MHz radars. The agreement between the model results and the observations show the high potential of remote sensing of dust and plasma parameters associated with PMWE. Measurement of Te/Ti using ISR and simultaneous observations in two frequency bands may lead to a more accurate estimation of dust density and radius. The enhancement of backscattered signal in the HF band during PMWE heating is predicted for the first time. The required background dust-plasma parameters as well as heater power (Te/Ti) for the observation of turn-on overshoot are investigated. It has been shown that the similarity of the temporal evolution of radar echoes in HF band and average charge on the dust particles can be used to study the fundamental physics associated with the dust charging in the PMWE source region. The possibilities of perusing PMWE heating experiments at HAARP will be discussed.

Thermal Modeling of a Hybrid Thermoelectric Solar Collector with a Compound Parabolic Concentrator

NASA Astrophysics Data System (ADS)

Lertsatitthanakorn, C.; Jamradloedluk, J.; Rungsiyopas, M.

2013-07-01

In this study radiant light from the sun is used by a hybrid thermoelectric (TE) solar collector and a compound parabolic concentrator (CPC) to generate electricity and thermal energy. The hybrid TE solar collector system described in this report is composed of transparent glass, an air gap, an absorber plate, TE modules, a heat sink to cool the water, and a storage tank. Incident solar radiation falls on the CPC, which directs and reflects the radiation to heat up the absorber plate, creating a temperature difference across the TE modules. The water, which absorbs heat from the hot TE modules, flows through the heat sink to release its heat. The results show that the electrical power output and the conversion efficiency depend on the temperature difference between the hot and cold sides of the TE modules. A maximum power output of 1.03 W and a conversion efficiency of 0.6% were obtained when the temperature difference was 12°C. The thermal efficiency increased as the water flow rate increased. The maximum thermal efficiency achieved was 43.3%, corresponding to a water flow rate of 0.24 kg/s. These experimental results verify that using a TE solar collector with a CPC to produce both electrical power and thermal energy seems to be feasible. The thermal model and calculation method can be applied for performance prediction.

Device and method for imploding a microsphere with a fast liner

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner to drive the fast liner to implode a microsphere.

Loop Heat Pipe Transient Behavior Using Heat Source Temperature for Set Point Control with Thermoelectric Converter on Reservoir

NASA Technical Reports Server (NTRS)

Ku, Jentung; Paiva, Kleber; Mantelli, Marcia

2011-01-01

The LHP operating temperature is governed by the saturation temperature of its reservoir. Controlling the reservoir saturation temperature is commonly done by cold biasing the reservoir and using electrical heaters to provide the required control power. With this method, the loop operating temperature can be controlled within 0.5K or better. However, because the thermal resistance that exists between the heat source and the LHP evaporator, the heat source temperature will vary with its heat output even if the LHP operating temperature is kept constant. Since maintaining a constant heat source temperature is of most interest, a question often raised is whether the heat source temperature can be used for LHP set point temperature control. A test program with a miniature LHP was carried out to investigate the effects on the LHP operation when the control temperature sensor was placed on the heat source instead of the reservoir. In these tests, the LHP reservoir was cold-biased and was heated by a control heater. Test results show that it was feasible to use the heat source temperature for feedback control of the LHP operation. In particular, when a thermoelectric converter was used as the reservoir control heater, the heat source temperature could be maintained within a tight range using a proportional-integral-derivative or on/off control algorithm. Moreover, because the TEC could provide both heating and cooling to the reservoir, temperature oscillations during fast transients such as loop startup could be eliminated or substantially reduced when compared to using an electrical heater as the control heater.

Energy saving analysis on mine-water source heat pump in a residential district of Henan province, central China

NASA Astrophysics Data System (ADS)

Wang, Hong; Duan, Huanlin; Chen, Aidong

2018-02-01

In this paper, the mine-water source heat pump system is proposed in residential buildings of a mining community. The coefficient of performance (COP) and the efficiency of exergy are analyzed. The results show that the COP and exergy efficiency of the mine-water source heat pump are improved, the exergy efficiency of mine-water source heat pump is more than 10% higher than that of the air source heat pump.The electric power conservation measure of “peak load shifting” is also emphasized in this article. It shows that itis a very considerable cost in the electric saving by adopting the trough period electricity to produce hot water. Due to the proper temperature of mine water, the mine-watersource heat pump unit is more efficient and stable in performance, which further shows the advantage of mine-water source heat pump in energy saving and environmental protection. It provides reference to the design of similar heat pump system as well.

Error field measurement, correction and heat flux balancing on Wendelstein 7-X

DOE PAGES

Lazerson, Samuel A.; Otte, Matthias; Jakubowski, Marcin; ...

2017-03-10

The measurement and correction of error fields in Wendelstein 7-X (W7-X) is critical to long pulse high beta operation, as small error fields may cause overloading of divertor plates in some configurations. Accordingly, as part of a broad collaborative effort, the detection and correction of error fields on the W7-X experiment has been performed using the trim coil system in conjunction with the flux surface mapping diagnostic and high resolution infrared camera. In the early commissioning phase of the experiment, the trim coils were used to open an n/m = 1/2 island chain in a specially designed magnetic configuration. Themore » flux surfacing mapping diagnostic was then able to directly image the magnetic topology of the experiment, allowing the inference of a small similar to 4 cm intrinsic island chain. The suspected main sources of the error field, slight misalignment and deformations of the superconducting coils, are then confirmed through experimental modeling using the detailed measurements of the coil positions. Observations of the limiters temperatures in module 5 shows a clear dependence of the limiter heat flux pattern as the perturbing fields are rotated. Plasma experiments without applied correcting fields show a significant asymmetry in neutral pressure (centered in module 4) and light emission (visible, H-alpha, CII, and CIII). Such pressure asymmetry is associated with plasma-wall (limiter) interaction asymmetries between the modules. Application of trim coil fields with n = 1 waveform correct the imbalance. Confirmation of the error fields allows the assessment of magnetic fields which resonate with the n/m = 5/5 island chain.« less

Proposal of experimental setup on boiling two-phase flow on-orbit experiments onboard Japanese experiment module "KIBO"

NASA Astrophysics Data System (ADS)

Baba, S.; Sakai, T.; Sawada, K.; Kubota, C.; Wada, Y.; Shinmoto, Y.; Ohta, H.; Asano, H.; Kawanami, O.; Suzuki, K.; Imai, R.; Kawasaki, H.; Fujii, K.; Takayanagi, M.; Yoda, S.

2011-12-01

Boiling is one of the efficient modes of heat transfer due to phase change, and is regarded as promising means to be applied for the thermal management systems handling a large amount of waste heat under high heat flux. However, gravity effects on the two-phase flow phenomena and corresponding heat transfer characteristics have not been clarified in detail. The experiments onboard Japanese Experiment Module "KIBO" in International Space Station on boiling two-phase flow under microgravity conditions are proposed to clarify both of heat transfer and flow characteristics under microgravity conditions. To verify the feasibility of ISS experiments on boiling two-phase flow, the Bread Board Model is assembled and its performance and the function of components installed in a test loop are examined.

Alkali Metal Handling Practices at NASA MSFC

NASA Technical Reports Server (NTRS)

Salvail, Patrick G.; Carter, Robert R.

2002-01-01

NASA Marshall Space Flight Center (MSFC) is NASA s principle propulsion development center. Research and development is coordinated and carried out on not only the existing transportation systems, but also those that may be flown in the near future. Heat pipe cooled fast fission cores are among several concepts being considered for the Nuclear Systems Initiative. Marshall Space Flight Center has developed a capability to handle high-purity alkali metals for use in heat pipes or liquid metal heat transfer loops. This capability is a low budget prototype of an alkali metal handling system that would allow the production of flight qualified heat pipe modules or alkali metal loops. The processing approach used to introduce pure alkali metal into heat pipe modules and other test articles are described in this paper.

An infrared-driven flexible pyroelectric generator for non-contact energy harvester

NASA Astrophysics Data System (ADS)

Zhao, Tingting; Jiang, Weitao; Liu, Hongzhong; Niu, Dong; Li, Xin; Liu, Weihua; Li, Xuan; Chen, Bangdao; Shi, Yongsheng; Yin, Lei; Lu, Bingheng

2016-04-01

In recent years, energy harvesting technologies, which can scavenge many kinds of energies from our living environment to power micro/nanodevices, have attracted increasing attention. However, remote energy transmission, flexibility and electric waveform controllability remain the key challenges for wireless power supply by an energy harvester. In this paper, we design a new infrared-driven non-contact pyroelectric generator for harvesting heat energy, which avoids direct contact between the pyroelectric generator and heat source and realizes remote energy transfer exploiting the photothermal and penetrability of infrared light. The output voltage (under the input impedance of 100 MOhm) and short-circuit current of the pyroelectric generator consisting of a CNT/PVDF/CNT layer (20 mm × 5 mm × 100 μm) can be as large as 1.2 V and 9 nA, respectively, under a 1.45 W cm-2 near-infrared laser (808 nm). We also demonstrate the means by which the pyroelectric generator can modulate square waveforms with controllable periods through irradiation frequency, which is essential for signal sources and medical stimulators. The overshoot of square waveforms are in a range of 9.0%-13.1% with a rise time of 120 ms. The prepared pyroelectric generator can light a liquid crystal display (LCD) in a vacuum chamber from outside. This work paves the way for non-contact energy harvesting for some particular occasions where near-field energy control is not available.In recent years, energy harvesting technologies, which can scavenge many kinds of energies from our living environment to power micro/nanodevices, have attracted increasing attention. However, remote energy transmission, flexibility and electric waveform controllability remain the key challenges for wireless power supply by an energy harvester. In this paper, we design a new infrared-driven non-contact pyroelectric generator for harvesting heat energy, which avoids direct contact between the pyroelectric generator and heat source and realizes remote energy transfer exploiting the photothermal and penetrability of infrared light. The output voltage (under the input impedance of 100 MOhm) and short-circuit current of the pyroelectric generator consisting of a CNT/PVDF/CNT layer (20 mm × 5 mm × 100 μm) can be as large as 1.2 V and 9 nA, respectively, under a 1.45 W cm-2 near-infrared laser (808 nm). We also demonstrate the means by which the pyroelectric generator can modulate square waveforms with controllable periods through irradiation frequency, which is essential for signal sources and medical stimulators. The overshoot of square waveforms are in a range of 9.0%-13.1% with a rise time of 120 ms. The prepared pyroelectric generator can light a liquid crystal display (LCD) in a vacuum chamber from outside. This work paves the way for non-contact energy harvesting for some particular occasions where near-field energy control is not available. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr09290f

Parallel-plate heat pipe apparatus having a shaped wick structure

DOEpatents

Rightley, Michael J.; Adkins, Douglas R.; Mulhall, James J.; Robino, Charles V.; Reece, Mark; Smith, Paul M.; Tigges, Chris P.

2004-12-07

A parallel-plate heat pipe is disclosed that utilizes a plurality of evaporator regions at locations where heat sources (e.g. semiconductor chips) are to be provided. A plurality of curvilinear capillary grooves are formed on one or both major inner surfaces of the heat pipe to provide an independent flow of a liquid working fluid to the evaporator regions to optimize heat removal from different-size heat sources and to mitigate the possibility of heat-source shadowing. The parallel-plate heat pipe has applications for heat removal from high-density microelectronics and laptop computers.

Convective heat transfer in a porous enclosure saturated by nanofluid with different heat sources

NASA Astrophysics Data System (ADS)

Muthtamilselvan, M.; Sureshkumar, S.

2018-03-01

The present study is proposed to investigate the effects of various lengths and different locations of the heater on the left sidewall in a square lid-driven porous cavity filled with nanofluid. A higher temperature is maintained on the left wall where three different lengths and three different locations of the heat source are considered for the analysis. The right wall is kept at a lower temperature while the top and bottom walls, and the remaining portions of the heated wall are adiabatic. The governing equations are solved by finite volume method. The results show that among the different lengths of the heat source, an enhancement in the heat transfer rate is observed only for the length LH = 1/3 of the heat source. In the case of location of the heat source, the overall heat transfer rate is increased when the heat source is located at the top of the hot wall. For Ri = 1 and 0.01, a better heat transfer rate is obtained when the heat source is placed at the top of the hot wall whereas for Ri = 100, it occurs when the heating portion is at the middle of the hot wall. As the solid volume fraction increases, the viscosity of the fluid is increased, which causes a reduction in the flow intensity. An addition of nanoparticles in the base fluid enhances the overall heat transfer rate significantly for all Da considered. The permeability of the porous medium plays a major role in convection of nanofluid than porosity. A high heat transfer rate (57.26%) is attained for Da = 10-1 and χ = 0.06.

Computational inverse methods of heat source in fatigue damage problems

NASA Astrophysics Data System (ADS)

Chen, Aizhou; Li, Yuan; Yan, Bo

2018-04-01

Fatigue dissipation energy is the research focus in field of fatigue damage at present. It is a new idea to solve the problem of calculating fatigue dissipation energy by introducing inverse method of heat source into parameter identification of fatigue dissipation energy model. This paper introduces the research advances on computational inverse method of heat source and regularization technique to solve inverse problem, as well as the existing heat source solution method in fatigue process, prospects inverse method of heat source applying in fatigue damage field, lays the foundation for further improving the effectiveness of fatigue dissipation energy rapid prediction.

Modular heat exchanger

DOEpatents

Culver, Donald W.

1978-01-01

A heat exchanger for use in nuclear reactors includes a heat exchange tube bundle formed from similar modules each having a hexagonal shroud containing a large number of thermally conductive tubes which are connected with inlet and outlet headers at opposite ends of each module, the respective headers being adapted for interconnection with suitable inlet and outlet manifold means. In order to adapt the heat exchanger for operation in a high temperature and high pressure environment and to provide access to all tube ports at opposite ends of the tube bundle, a spherical tube sheet is arranged in sealed relation across the chamber with an elongated duct extending outwardly therefrom to provide manifold means for interconnection with the opposite end of the tube bundle.

Optimization of power generating thermoelectric modules utilizing LNG cold energy

NASA Astrophysics Data System (ADS)

Jeong, Eun Soo

2017-12-01

A theoretical investigation to optimize thermoelectric modules, which convert LNG cold energy into electrical power, is performed using a novel one-dimensional analytic model. In the model the optimum thermoelement length and external load resistance, which maximize the energy conversion ratio, are determined by the heat supplied to the cold heat reservoir, the hot and cold side temperatures, the thermal and electrical contact resistances and the properties of thermoelectric materials. The effects of the thermal and electrical contact resistances and the heat supplied to the cold heat reservoir on the maximum energy conversion ratio, the optimum thermoelement length and the optimum external load resistance are shown.

Space Power Free-Piston Stirling Engine Scaling Study

NASA Technical Reports Server (NTRS)

Jones, D.

1989-01-01

The design feasibility study is documented of a single cylinder, free piston Stirling engine/linear alternator (FPSE/LA) power module generating 150 kW-electric (kW sub e), and the determination of the module's maximum feasible power level. The power module configuration was specified to be a single cylinder (single piston, single displacer) FPSE/LA, with tuning capacitors if required. The design requirements were as follows: (1) Maximum electrical power output; (2) Power module thermal efficiency equal to or greater than 20 percent at a specific mass of 5 to 8 kg/kW(sub e); (3) Heater wall temperature/cooler wall temperature = 1050 K/525 K; (4) Sodium heat-pipe heat transport system, pumped loop NaK (sodium-potassium eutectic mixture) rejection system; (5) Maximum power module vibration amplitude = 0.0038 cm; and (6) Design life = 7 years (60,000 hr). The results show that a single cylinder FPSE/LA is capable of meeting program goals and has attractive scaling attributes over the power range from 25 to 150 kW(sub e). Scaling beyond the 150 kW(sub e) power level, the power module efficiency falls and the power module specific mass reaches 10 kg/kW(sub e) at a power output of 500 kW(sub e). A discussion of scaling rules for the engine, alternator, and heat transport systems is presented, along with a detailed description of the conceptual design of a 150 kW(sub e) power module that meets the requirements. Included is a discussion of the design of a dynamic balance system. A parametric study of power module performance conducted over the power output range of 25 to 150 kW(sub e) for temperature ratios of 1.7, 2.0, 2.5, and 3.0 is presented and discussed. The results show that as the temperature ratio decreases, the efficiency falls and specific mass increases. At a temperature ratio of 1.7, the 150 kW(sub e) power module cannot satisfy both efficiency and specific mass goals. As the power level increases from 25 to 150 kW(sub e) at a fixed temperature ratio, power module efficiency is seen to increase slightly, but at the expense of increased specific mass. An empirical equation relating power module thermal efficiency as a function of power module specific mass, power output, and temperature ratio is developed. Alternative configurations to the single cylinder, direct coupled linear alternator approach are also evaluated, but are shown to have technical drawbacks that lessen their attractiveness. The dynamic balance assembly mass (moving mass and structure) represents 20 to 30 percent of the total single cylinder power module mass. Joining two modules in a balanced opposed configuration eliminates the need for the balancer, and a hot end junction can be made without significant addition of structural mass. Recommendations are made for evaluation of advanced heat pipe concepts, tests of radial flow heat exchangers, and evaluation of high temperature alternator materials.

Power-Stepped HF Cross-Modulation Experiments: Simulations and Experimental Observations

NASA Astrophysics Data System (ADS)

Greene, S.; Moore, R. C.

2014-12-01

High frequency (HF) cross modulation experiments are a well established means for probing the HF-modified characteristics of the D-region ionosphere. The interaction between the heating wave and the probing pulse depends on the ambient and modified conditions of the D-region ionosphere. Cross-modulation observations are employed as a measure of the HF-modified refractive index. We employ an optimized version of Fejer's method that we developed during previous experiments. Experiments were performed in March 2013 at the High Frequency Active Auroral Research Program (HAARP) observatory in Gakona, Alaska. During these experiments, the power of the HF heating signal incrementally increased in order to determine the dependence of cross-modulation on HF power. We found that a simple power law relationship does not hold at high power levels, similar to previous ELF/VLF wave generation experiments. In this paper, we critically compare these experimental observations with the predictions of a numerical ionospheric HF heating model and demonstrate close agreement.

Spatial Manipulation of Heat Flow by Surface Boundaries at the Nanoscale

NASA Astrophysics Data System (ADS)

Malhotra, Abhinav; Maldovan, Martin

The precise manipulation of phonon transport properties is central to controlling thermal transport in semiconductor nanostructures. The physical understanding, prediction, and control of thermal phonon heat spectra and thermal conductivity accumulation functions - which establish the proportion of heat transported by phonons with different frequencies and mean-free-paths - has attracted significant attention in recent years. In this talk, we advance the possibilities of manipulating heat by spatially modulating thermal transport in nanostructures. We show that phonon scattering at interfaces impacts the most preferred physical pathway used by heat energy flow in thermal transport in nanostructures. The role of introducing boundaries with different surface conditions on resultant thermal flux is presented and methodologies to enhance these spatial modulations are discussed. This talk aims to advance the fundamental understanding on the nature of heat transport at nanoscale with potential applications in multiple research areas ranging from energy materials to optoelectronics.

A review on hyperthermia via nanoparticle-mediated therapy.

PubMed

Sohail, Ayesha; Ahmad, Zaki; Bég, O Anwar; Arshad, Sarmad; Sherin, Lubna

2017-05-01

Hyperthermia treatment, generated by magnetic nanoparticles (MNPs) is promising since it is tumour-focused, minimally invasive and uniform. The most unique feature of magnetic nanoparticles is its reaction and modulation by a magnetic force basically responsible for enabling its potential as heating mediators for cancer therapy. In magnetic nanoparticle hyperthermia, a tumour is preferentially loaded with systemically administered nanoparticles with high-absorption cross-section for transduction of an extrinsic energy source to heat. To maximize the energy deposited in the tumour while limiting the exposure to healthy tissues, the heating is achieved by exposing the region of tissue containing magnetic nanoparticles to an alternating magnetic field. The magnetic nanoparticles dissipate heat from relaxation losses thereby heating localized tissue above normal physiological ranges. Besides thermal efficiency, the biocompatibility of magnetite nanoparticles assisted its deployment as efficient drug carrier for targeted therapeutic regimes. In the present article, we provide a state-of-the-art review focused on progress in nanoparticle induced hyperthermia treatments that have several potential advantages over both global and local hyperthermia treatments achieved without nanoparticles. Green bio-nanotechnology has attracted substantial attention and has demonstrable abilities to improve cancer therapy. Furthermore, we have listed the challenges associated with this treatment along with future prospective that could attract the interest of biomedical engineers, biomaterials scientists, medical researchers and pharmacological research groups. Copyright © 2017 Société Française du Cancer. All rights reserved.

Radioisotopic heat source

DOEpatents

Sayell, E.H.

1973-10-23

A radioisotopic heat source is described which includes a core of heat productive, radioisotopic material, an impact resistant layer of graphite surrounding said core, and a shell of iridium metal intermediate the core and the impact layer. The source may also include a compliant mat of iridium between the core and the iridium shell, as well as an outer covering of iridium metal about the entire heat source. (Official Gazette)

Potential-Induced Degradation-Delamination Mode in Crystalline Silicon Modules: Preprint

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

Hacke, Peter L; Kempe, Michael D; Wohlgemuth, John

A test sequence producing potential-induced degradation-delamination (PID-d) in crystalline silicon modules has been tested and found comparable under visual inspection to cell/encapsulant delamination seen in some fielded modules. Four commercial modules were put through this sequence, 85 degrees C, 85%, 1000 h damp heat, followed by an intensive PID stress sequence of 72 degrees C, 95% RH, and -1000 V, with the module face grounded using a metal foil. The 60 cell c-Si modules exhibiting the highest current transfer (4.4 center dot 10-4 A) exhibited PID-d at the first inspection after 156 h of PID stress. Effects promoting PID-d aremore » reduced adhesion caused by damp heat, sodium migration further reducing adhesion to the cells, and gaseous products of electrochemical reactions driven by the applied system voltage. A new work item proposal for an IEC test standard to evaluate for PID-d is anticipated.« less

Processing of whey modulates proliferative and immune functions in intestinal epithelial cells.

PubMed

Nguyen, Duc Ninh; Sangild, Per T; Li, Yanqi; Bering, Stine B; Chatterton, Dereck E W

2016-02-01

Whey protein concentrate (WPC) is often subjected to heat treatment during industrial processing, resulting in protein denaturation and loss of protein bioactivity. We hypothesized that WPC samples subjected to different degrees of thermal processing are associated with different levels of bioactive proteins and effects on proliferation and immune response in intestinal epithelial cells (IEC). The results showed that low-heat-treated WPC had elevated levels of lactoferrin and transforming growth factor-β2 compared with that of standard WPC. The level of aggregates depended on the source of whey, with the lowest level being found in WPC derived from acid whey. Following acid activation, WPC from acid whey enhanced IEC proliferation compared with WPC from sweet whey or nonactivated WPC. Low-heat-treated WPC from acid whey induced greater secretion of IL-8 in IEC than either standard WPC from acid whey or low-heat-treated WPC from sweet whey. Following acid activation (to activate growth factors), low-heat-treated WPC from sweet whey induced higher IL-8 levels in IEC compared with standard WPC from sweet whey. In conclusion, higher levels of bioactive proteins in low-heat-treated WPC, especially from acid whey, may enhance proliferation and cytokine responses of IEC. These considerations could be important to maintain optimal bioactivity of infant formulas, including their maturational and immunological effects on the developing intestine. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Thermal Management Optimization of a Thermoelectric-Integrated Methanol Evaporator Using a Compact CFD Modeling Approach

NASA Astrophysics Data System (ADS)

Gao, Xin; Chen, Min; Snyder, G. Jeffrey; Andreasen, Søren Juhl; Kær, Søren Knudsen

2013-07-01

To better manage the magnitude and direction of the heat flux in an exchanger-based methanol evaporator of a fuel cell system, thermoelectric (TE) modules can be deployed as TE heat flux regulators (TERs). The performance of the TE-integrated evaporator is strongly influenced by its heat exchange structure. The structure transfers the fuel cell exhaust heat to the evaporation chamber to evaporate the methanol, where TE modules are installed in between to facilitate the heat regulation. In this work, firstly, a numerical study is conducted to determine the working currents and working modes of the TERs under the system working condition fluctuations and during the system cold start. A three-dimensional evaporator model is generated in ANSYS FLUENT® by combining a compact TE model with various heat exchange structure geometries. The compact TE model can dramatically improve the computational efficiency, and uses a different material property acquisition method based on module manufacturers' datasheets. Secondly, a simulation study is carried out on the novel evaporator to minimize its thermal resistance and to assess the evaporator pressure drop. The factors studied include the type of fins in the heat exchange structure, the thickness of the fins, the axial conduction penalty, etc. Results show that the TE-integrated evaporator can work more efficiently and smoothly during both load fluctuations and system cold start, offering superior performance.

GhMAP3K65, a Cotton Raf-Like MAP3K Gene, Enhances Susceptibility to Pathogen Infection and Heat Stress by Negatively Modulating Growth and Development in Transgenic Nicotiana benthamiana.

PubMed

Zhai, Na; Jia, Haihong; Liu, Dongdong; Liu, Shuchang; Ma, Manli; Guo, Xingqi; Li, Han

2017-11-21

Mitogen-activated protein kinase kinase kinases (MAP3Ks), the top components of MAPK cascades, modulate many biological processes, such as growth, development and various environmental stresses. Nevertheless, the roles of MAP3Ks remain poorly understood in cotton. In this study, GhMAP3K65 was identified in cotton, and its transcription was inducible by pathogen infection, heat stress, and multiple signalling molecules. Silencing of GhMAP3K65 enhanced resistance to pathogen infection and heat stress in cotton. In contrast, overexpression of GhMAP3K65 enhanced susceptibility to pathogen infection and heat stress in transgenic Nicotiana benthamiana . The expression of defence-associated genes was activated in transgenic N. benthamiana plants after pathogen infection and heat stress, indicating that GhMAP3K65 positively regulates plant defence responses. Nevertheless, transgenic N. benthamiana plants impaired lignin biosynthesis and stomatal immunity in their leaves and repressed vitality of their root systems. In addition, the expression of lignin biosynthesis genes and lignin content were inhibited after pathogen infection and heat stress. Collectively, these results demonstrate that GhMAP3K65 enhances susceptibility to pathogen infection and heat stress by negatively modulating growth and development in transgenic N. benthamiana plants.

Optimum load distribution between heat sources based on the Cournot model

NASA Astrophysics Data System (ADS)

Penkovskii, A. V.; Stennikov, V. A.; Khamisov, O. V.

2015-08-01

One of the widespread models of the heat supply of consumers, which is represented in the "Single buyer" format, is considered. The methodological base proposed for its description and investigation presents the use of principles of the theory of games, basic propositions of microeconomics, and models and methods of the theory of hydraulic circuits. The original mathematical model of the heat supply system operating under conditions of the "Single buyer" organizational structure provides the derivation of a solution satisfying the market Nash equilibrium. The distinctive feature of the developed mathematical model is that, along with problems solved traditionally within the bounds of bilateral relations of heat energy sources-heat consumer, it considers a network component with its inherent physicotechnical properties of the heat network and business factors connected with costs of the production and transportation of heat energy. This approach gives the possibility to determine optimum levels of load of heat energy sources. These levels provide the given heat energy demand of consumers subject to the maximum profit earning of heat energy sources and the fulfillment of conditions for formation of minimum heat network costs for a specified time. The practical realization of the search of market equilibrium is considered by the example of a heat supply system with two heat energy sources operating on integrated heat networks. The mathematical approach to the solution search is represented in the graphical form and illustrates computations based on the stepwise iteration procedure for optimization of levels of loading of heat energy sources (groping procedure by Cournot) with the corresponding computation of the heat energy price for consumers.

Heating device for semiconductor wafers

DOEpatents

Vosen, Steven R.

1999-01-01

An apparatus for heat treating semiconductor wafers is disclosed. The apparatus includes a heating device which contains an assembly of light energy sources for emitting light energy onto a wafer. In particular, the light energy sources are positioned such that many different radial heating zones are created on a wafer being heated. For instance, in one embodiment, the light energy sources form a spiral configuration. In an alternative embodiment, the light energy sources appear to be randomly dispersed with respect to each other so that no discernable pattern is present. In a third alternative embodiment of the present invention, the light energy sources form concentric rings. Tuning light sources are then placed in between the concentric rings of light.

Heating device for semiconductor wafers

DOEpatents

Vosen, S.R.

1999-07-27

An apparatus for heat treating semiconductor wafers is disclosed. The apparatus includes a heating device which contains an assembly of light energy sources for emitting light energy onto a wafer. In particular, the light energy sources are positioned such that many different radial heating zones are created on a wafer being heated. For instance, in one embodiment, the light energy sources form a spiral configuration. In an alternative embodiment, the light energy sources appear to be randomly dispersed with respect to each other so that no discernible pattern is present. In a third alternative embodiment of the present invention, the light energy sources form concentric rings. Tuning light sources are then placed in between the concentric rings of light. 4 figs.

Neutronic calculation of fast reactors by the EUCLID/V1 integrated code

NASA Astrophysics Data System (ADS)

Koltashev, D. A.; Stakhanova, A. A.

2017-01-01

This article considers neutronic calculation of a fast-neutron lead-cooled reactor BREST-OD-300 by the EUCLID/V1 integrated code. The main goal of development and application of integrated codes is a nuclear power plant safety justification. EUCLID/V1 is integrated code designed for coupled neutronics, thermomechanical and thermohydraulic fast reactor calculations under normal and abnormal operating conditions. EUCLID/V1 code is being developed in the Nuclear Safety Institute of the Russian Academy of Sciences. The integrated code has a modular structure and consists of three main modules: thermohydraulic module HYDRA-IBRAE/LM/V1, thermomechanical module BERKUT and neutronic module DN3D. In addition, the integrated code includes databases with fuel, coolant and structural materials properties. Neutronic module DN3D provides full-scale simulation of neutronic processes in fast reactors. Heat sources distribution, control rods movement, reactivity level changes and other processes can be simulated. Neutron transport equation in multigroup diffusion approximation is solved. This paper contains some calculations implemented as a part of EUCLID/V1 code validation. A fast-neutron lead-cooled reactor BREST-OD-300 transient simulation (fuel assembly floating, decompression of passive feedback system channel) and cross-validation with MCU-FR code results are presented in this paper. The calculations demonstrate EUCLID/V1 code application for BREST-OD-300 simulating and safety justification.

Thermo-plasmonics: playing with temperature at the nanoscale (Conference Presentation)

NASA Astrophysics Data System (ADS)

Alabastri, Alessandro; Malerba, Mario; Calandrini, Eugenio; Toma, Andrea; Proietti Zaccaria, Remo

2017-02-01

The electro-magnetic field generated within and around dissipative nano-structures upon light radiation is intimately associated to the formation of localized heat sources. In turn, this phenomenon determines localized temperature variations, effect which can be exploited for applications such as photocatalysis [1], nanochemistry [2] or sensor devices [3]. Here we show how the geometrical characteristics of plasmonic nano-structures can indeed be used to modulate the temperature response. The idea is that when metallic structures interact with an electromagnetic field they heat up due to Joule effect. The corresponding temperature variation modifies the optical response of the structure [4,5] and thus its heating process. The key finding is that, depending on the structures geometry, absorption efficiency can either increase or decrease with temperature. Since absorption relates to the thermal energy dissipation and thus to temperature increase, the mechanism leads to positive or negative loops. Consequently, not only an error would be made by neglecting the role of temperature, but it would be not even possible to know, a priori, if the error is towards higher or lower absorption values. Our model can be utilized to study opto-thermal phenomena when high temperature or high intensity sources are employed. [1] M. Honda et al., Appl. Phys. Lett. 104, 061108 (2014) [2] G. Baffou et al., Chem. Soc. Rev. 43, 3898 (2014) [3] S. Ozdemir et al., J. Lightwave Tech. 21, 805 (2003) [4] A. Alabastri et al., ACS Photonics 2, 115 (2015) [5] A. Alabastri et al., Materials 6, 4879 (2013)

Solar electricity and solar fuels

NASA Astrophysics Data System (ADS)

Spiers, David J.

1989-04-01

The nature of solar radiation and its variation with location is described. The distribution of energy in the solar spectrum places immediate limits on the theoretical efficiency of conversion processes, since practical absorbers cannot convert all wavelengths received to useful energy. The principles of solar energy conversion methods are described. Absorption of solar energy can give rise to direct electrical generation, heating, or chemical change. Electrical generation from sunlight can be achieved by photovoltaic systems directly or by thermal systems which use solar heat to drive a heat engine and generator. The technology used and under research for promising ways of producing electricity or fuel from solar energy is described. Photovoltaic technology is established today for remote area, small power applications, and photovoltaic module sales alone are over 100 million dollars per year at present. The photovoltaic market has grown steadily since the mid-1970's, as prices have fallen continuously. Future energy options are briefly described. The merits of a sustainable energy economy, based on renewable energy resources, including solar energy, are emphasized, as this seems to provide the only hope of eliminating the problems caused by the build-up of atmospheric carbon dioxide, acid rain pollution and nuclear waste disposal. There is no doubt that clean fuels which were derived from solar energy and either did not involve carbon dioxide and used atmospheric carbon dioxide as the source dioxide as the source of carbon would be a worthy ideal. Methods described could one day achieve this.

Spatial and temporal control of thermal waves by using DMDs for interference based crack detection

NASA Astrophysics Data System (ADS)

Thiel, Erik; Kreutzbruck, Marc; Ziegler, Mathias

2016-02-01

Active Thermography is a well-established non-destructive testing method and used to detect cracks, voids or material inhomogeneities. It is based on applying thermal energy to a samples' surface whereas inner defects alter the nonstationary heat flow. Conventional excitation of a sample is hereby done spatially, either planar (e.g. using a lamp) or local (e.g. using a focused laser) and temporally, either pulsed or periodical. In this work we combine a high power laser with a Digital Micromirror Device (DMD) allowing us to merge all degrees of freedom to a spatially and temporally controlled heat source. This enables us to exploit the possibilities of coherent thermal wave shaping. Exciting periodically while controlling at the same time phase and amplitude of the illumination source induces - via absorption at the sample's surface - a defined thermal wave propagation through a sample. That means thermal waves can be controlled almost like acoustical or optical waves. However, in contrast to optical or acoustical waves, thermal waves are highly damped due to the diffusive character of the thermal heat flow and therefore limited in penetration depth in relation to the achievable resolution. Nevertheless, the coherence length of thermal waves can be chosen in the mmrange for modulation frequencies below 10 Hz which is perfectly met by DMD technology. This approach gives us the opportunity to transfer known technologies from wave shaping techniques to thermography methods. We will present experiments on spatial and temporal wave shaping, demonstrating interference based crack detection.

Real-time temperature feedback for nanoparticles based tumor thermal treatment (Conference Presentation)

NASA Astrophysics Data System (ADS)

Steinberg, Idan; Tamir, Gil; Gannot, Israel

2017-02-01

Systemic hyperthermia therapy exploits the fact that cancer cells are more sensitive to elevated temperatures than healthy tissue. Systemic application of hyperthermia externally usually leads to low efficiency treatment. Recently, our group and others have proposed an antibody conjugated magnetic nanoparticles (MNPs) approach to overcome the limitation of systemic hyperthermia. MNPs can bind specifically to the tumor sites, thus delivering internal highly effective targeted hyperthermia. However, such internal mechanism requires more complicated controls and monitoring. This current work presents a deep tissue temperature monitoring method to control hyperthermia effectiveness and minimize collateral damage to surrounding tissues. A low-frequency narrowband modulation of the RF field used for MNP heating leads to the generation of diffused thermal waves which propagate to the tissue surface and captured by a thermal camera. A Fourier domain, analytical heat transfer model is used for temperature monitoring algorithm. The ill-posed thermal inverse problem is solved efficiently by iterating over the source power until both the amplitude and phase match the recorded thermal image sequence. The narrow bandwidth thermal stimulation enables acquiring deep signals with high SNR. We show that thermal transverse resolution improves as the stimulation frequency increases even slightly above DC, enabling better heat source transverse separation and margin identification in the case of distributed tumors. These results can be used as a part of an overall image and treat system for efficient detection of tumors, manipulation of MNPs and monitoring MNP based hyperthermia.

A Simulation Study on a Thermoelectric Generator for Waste Heat Recovery from a Marine Engine

NASA Astrophysics Data System (ADS)

Ji, Dongxu; Tseng, King Jet; Wei, Zhongbao; Zheng, Yun; Romagnoli, Alessandro

2017-05-01

In this study, a marine engine has been evaluated for waste heat recovery (WHR) using thermoelectric generators (TEG). The feasibility of Mg2Sn0.75Ge0.25, Cu2Se, and Cu1.98Se as potential thermoelectric (TE) material were investigated. A straight fin heat exchanger is used to enhance the heat transfer between the hot exhaust gas and TE modules. To facility the analysis, a system level thermal resistance model is built and validated with experiments. After the model is validated, a small marine engine with rated power of 1.7-3 MW is taken as baseline model and it is found that around 2-4 KW electrical power can be extracted from exhaust gas by the TEG at varying design and operating parameters. The back pressure effect induced by the heat exchanger is also considered in this study. Finally, a parameter study is conducted regarding the impact of the TE module height on the output power. It is shown that the height of the TE leg could play a significant role in the module geometry design, and that the optimal height varies between 1 mm and 2 mm under different heat exchangers and exhaust gas flow rates.

Lozier Corporation Workplace Literacy Modules. Alabama Partnership for Training.

ERIC Educational Resources Information Center

Alabama State Dept. of Education, Montgomery.

This packet contains 10 learning modules developed for new employees at the Lozier Corporation, as well as a facilitator's manual for teaching the modules. The modules cover the following topics: (1) introduction; (2) Lozier history; (3) personal protective equipment, heat stress and back injuries, and evacuation and housekeeping; (4) bloodborne…

Method and apparatus for fuel gas moisturization and heating

DOEpatents

Ranasinghe, Jatila; Smith, Raub Warfield

2002-01-01

Fuel gas is saturated with water heated with a heat recovery steam generator heat source. The heat source is preferably a water heating section downstream of the lower pressure evaporator to provide better temperature matching between the hot and cold heat exchange streams in that portion of the heat recovery steam generator. The increased gas mass flow due to the addition of moisture results in increased power output from the gas and steam turbines. Fuel gas saturation is followed by superheating the fuel, preferably with bottom cycle heat sources, resulting in a larger thermal efficiency gain compared to current fuel heating methods. There is a gain in power output compared to no fuel heating, even when heating the fuel to above the LP steam temperature.

A high reliability module with thermoelectric device by molding technology for M2M wireless sensor network

NASA Astrophysics Data System (ADS)

Nakagawa, K.; Tanaka, T.; Suzuki, T.

2015-10-01

This paper presents the fabrication of a new energy harvesting module that uses a thermoelectric device (TED) by using molding technology. Through molding technology, the TED and circuit board can be properly protected and a heat-radiating fin structure can be simultaneously constructed. The output voltage per heater temperature of the TED module at 20 °C ambient temperature is 8 mV K-1, similar to the result with the aluminum heat sink which is almost the same fin size as the TED module. The accelerated environmental tests are performed on a damp heat test, which is an aging test under high temperature and high humidity, highly accelerated temperature, and humidity stress test (HAST) for the purpose of evaluating the electrical reliability in harsh environments, cold test and thermal cycle test to evaluate degrading characteristics by cycling through two temperatures. All test results indicate that the TED and circuit board can be properly protected from harsh temperature and humidity by using molding technology because the output voltage of after-tested modules is reduced by less than 5%. This study presents a novel fabrication method for a high reliability TED-installed module appropriate for Machine to Machine wireless sensor networks.

Reducing Operating Temperature in Photovoltaic Modules

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

Silverman, Timothy J.; Deceglie, Michael G.; Subedi, Indra

Reducing the operating temperature of photovoltaic modules increases their efficiency and lifetime. This can be achieved by reducing the production of waste heat or by improving the rejection of waste heat. We tested, using a combination of simulation and experiment, several thermal modifications in each category. To predict operating temperature and energy yield changes in response to changes to the module, we implemented a physics-based transient simulation framework based almost entirely on measured properties. The most effective thermal modifications reduced the production of waste heat by reflecting unusable light from the cell or the module. Consistent with previous results andmore » verified in this work through year-long simulations, the ideal reflector resulted in an annual irradiance-weighted temperature reduction of 3.8 K for crystalline silicon (c-Si). Our results illustrate that more realistic reflector concepts must balance detrimental optical effects with the intended thermal effects to realize the optimal energy production advantage. Methods improving thermal conductivity or back-side emissivity showed only modest improvements of less than 1 K. We also studied a GaAs module, which uses high-efficiency and high-subbandgap reflectivity to operate at an annual irradiance-weighted temperature 12 K cooler than that of a c-Si module under the same conditions.« less

Reducing Operating Temperature in Photovoltaic Modules

DOE PAGES

Silverman, Timothy J.; Deceglie, Michael G.; Subedi, Indra; ...

2018-01-09

Reducing the operating temperature of photovoltaic modules increases their efficiency and lifetime. This can be achieved by reducing the production of waste heat or by improving the rejection of waste heat. We tested, using a combination of simulation and experiment, several thermal modifications in each category. To predict operating temperature and energy yield changes in response to changes to the module, we implemented a physics-based transient simulation framework based almost entirely on measured properties. The most effective thermal modifications reduced the production of waste heat by reflecting unusable light from the cell or the module. Consistent with previous results andmore » verified in this work through year-long simulations, the ideal reflector resulted in an annual irradiance-weighted temperature reduction of 3.8 K for crystalline silicon (c-Si). Our results illustrate that more realistic reflector concepts must balance detrimental optical effects with the intended thermal effects to realize the optimal energy production advantage. Methods improving thermal conductivity or back-side emissivity showed only modest improvements of less than 1 K. We also studied a GaAs module, which uses high-efficiency and high-subbandgap reflectivity to operate at an annual irradiance-weighted temperature 12 K cooler than that of a c-Si module under the same conditions.« less

Thermal diffusivity measurement in thin metallic filaments using the mirage method with multiple probe beams and a digital camera

NASA Astrophysics Data System (ADS)

Vargas, E.; Cifuentes, A.; Alvarado, S.; Cabrera, H.; Delgado, O.; Calderón, A.; Marín, E.

2018-02-01

Photothermal beam deflection is a well-established technique for measuring thermal diffusivity. In this technique, a pump laser beam generates temperature variations on the surface of the sample to be studied. These variations transfer heat to the surrounding medium, which may be air or any other fluid. The medium in turn experiences a change in the refractive index, which will be proportional to the temperature field on the sample surface when the distance to this surface is small. A probe laser beam will suffer a deflection due to the refractive index periodical changes, which is usually monitored by means of a quadrant photodetector or a similar device aided by lock-in amplification. A linear relationship that arises in this technique is that given by the phase lag of the thermal wave as a function of the distance to a punctual heat source when unidimensional heat diffusion can be guaranteed. This relationship is useful in the calculation of the sample's thermal diffusivity, which can be obtained straightforwardly by the so-called slope method, if the pump beam modulation frequency is well-known. The measurement procedure requires the experimenter to displace the probe beam at a given distance from the heat source, measure the phase lag at that offset, and repeat this for as many points as desired. This process can be quite lengthy in dependence of the number points. In this paper, we propose a detection scheme, which overcomes this limitation and simplifies the experimental setup using a digital camera that substitutes all detection hardware utilizing motion detection techniques and software digital signal lock-in post-processing. In this work, the method is demonstrated using thin metallic filaments as samples.

Thermal diffusivity measurement in thin metallic filaments using the mirage method with multiple probe beams and a digital camera.

PubMed

Vargas, E; Cifuentes, A; Alvarado, S; Cabrera, H; Delgado, O; Calderón, A; Marín, E

2018-02-01

Photothermal beam deflection is a well-established technique for measuring thermal diffusivity. In this technique, a pump laser beam generates temperature variations on the surface of the sample to be studied. These variations transfer heat to the surrounding medium, which may be air or any other fluid. The medium in turn experiences a change in the refractive index, which will be proportional to the temperature field on the sample surface when the distance to this surface is small. A probe laser beam will suffer a deflection due to the refractive index periodical changes, which is usually monitored by means of a quadrant photodetector or a similar device aided by lock-in amplification. A linear relationship that arises in this technique is that given by the phase lag of the thermal wave as a function of the distance to a punctual heat source when unidimensional heat diffusion can be guaranteed. This relationship is useful in the calculation of the sample's thermal diffusivity, which can be obtained straightforwardly by the so-called slope method, if the pump beam modulation frequency is well-known. The measurement procedure requires the experimenter to displace the probe beam at a given distance from the heat source, measure the phase lag at that offset, and repeat this for as many points as desired. This process can be quite lengthy in dependence of the number points. In this paper, we propose a detection scheme, which overcomes this limitation and simplifies the experimental setup using a digital camera that substitutes all detection hardware utilizing motion detection techniques and software digital signal lock-in post-processing. In this work, the method is demonstrated using thin metallic filaments as samples.

Changes in concentration, composition and source contribution of atmospheric organic aerosols by shifting coal to natural gas in Urumqi

NASA Astrophysics Data System (ADS)

Ren, Yanqin; Wang, Gehui; Wu, Can; Wang, Jiayuan; Li, Jianjun; Zhang, Lu; Han, Yanni; Liu, Lang; Cao, Cong; Cao, Junji; He, Qing; Liu, Xinchun

2017-01-01

Size-segregated aerosols were collected in Urumqi, a megacity in northwest China, during two heating seasons, i.e., before (heating season І: January-March 2012) and after (heating season II: January-March 2014) the project "shifting coal to natural gas", and determined for n-alkanes, PAHs and oxygenated PAHs to investigate the impact of replacement of coal by natural gas on organic aerosols in the urban atmosphere. Our results showed that compared to those in heating season I concentrations of n-alkanes, PAHs and OPAHs decreased by 74%, 74% and 82% in heating season II, respectively. Source apportionment analysis suggested that coal combustion, traffic emission and biomass burning are the major sources of the determined organics during the heating seasons in Urumqi. Traffic emission is the main source for n-alkanes in the city. Coal combustion is the dominant source of PAHs and OPAHs in heating season І, but traffic emission becomes their major source in heating season ІI. Relative contributions of coal combustion to n-alkanes, PAHs and OPAHs in Urumqi decreased from 21 to 75% in heating season I to 4.0-21% in heating season II due to the replacement of coal with natural gas for house heating. Health risk assessment further indicated that compared with that in heating season I the number of lung cancer related to PAHs exposure in Urumqi decreased by 73% during heating season II due to the project implementation. Our results suggest that replacing coal by clean energy sources for house heating will significantly mitigate air pollution and improve human health in China.

Parametric Optimization of Thermoelectric Generators for Waste Heat Recovery

NASA Astrophysics Data System (ADS)

Huang, Shouyuan; Xu, Xianfan

2016-10-01

This paper presents a methodology for design optimization of thermoelectric-based waste heat recovery systems called thermoelectric generators (TEGs). The aim is to maximize the power output from thermoelectrics which are used as add-on modules to an existing gas-phase heat exchanger, without negative impacts, e.g., maintaining a minimum heat dissipation rate from the hot side. A numerical model is proposed for TEG coupled heat transfer and electrical power output. This finite-volume-based model simulates different types of heat exchangers, i.e., counter-flow and cross-flow, for TEGs. Multiple-filled skutterudites and bismuth-telluride-based thermoelectric modules (TEMs) are applied, respectively, in higher and lower temperature regions. The response surface methodology is implemented to determine the optimized TEG size along and across the flow direction and the height of thermoelectric couple legs, and to analyze their covariance and relative sensitivity. A genetic algorithm is employed to verify the globality of the optimum. The presented method will be generally useful for optimizing heat-exchanger-based TEG performance.

Sleeve reaction chamber system

DOEpatents

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

2009-08-25

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

Preliminary evaluation of a space AMTEC power conversion system

NASA Technical Reports Server (NTRS)

Crowley, Christopher J.; Sievers, Robert K.

1991-01-01

As original evaluation of a space solar energy source coupled with Alkali Metal Thermoelectric Conversion (AMTEC) is presented here. This study indicates that an AMTEC system would have 30 percent of the mass of a photovoltaic system and 70 percent of the mass of a Stirling cycle system at the 35-kWe level of power generation modules typical of the baseline for the U.S. Space Station. The operating temperatures and sodium heat pipe components for solar receiver/TES hardware (currently being developed by NASA) integrate well with AMTEC power conversion. AMTEC is therefore an attractive alternative specifically for space solar power generation.

10 CFR 431.92 - Definitions concerning commercial air conditioners and heat pumps.

Code of Federal Regulations, 2010 CFR

2010-01-01

... wall, and that is industrial equipment. It includes a prime source of refrigeration, separable outdoor... refrigeration as its prime heat source, that has a supplementary heat source available, with the choice of hot... water, or gas, but may not include reverse cycle refrigeration as a heating means. Single package...

10 CFR 431.92 - Definitions concerning commercial air conditioners and heat pumps.

Code of Federal Regulations, 2011 CFR

2011-01-01

... wall, and that is industrial equipment. It includes a prime source of refrigeration, separable outdoor... refrigeration as its prime heat source, that has a supplementary heat source available, with the choice of hot... water, or gas, but may not include reverse cycle refrigeration as a heating means. Single package...

10 CFR 431.92 - Definitions concerning commercial air conditioners and heat pumps.

Code of Federal Regulations, 2012 CFR

2012-01-01

... mounting through the wall, and that is industrial equipment. It includes a prime source of refrigeration... utilizes reverse cycle refrigeration as its prime heat source, that has a supplementary heat source..., hot water, or gas, but may not include reverse cycle refrigeration as a heating means. Single package...

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

Kim, G.-H.; Pesaran, A.; Smith, K.

The objectives of this paper are: (1) continue to explore thermal abuse behaviors of Li-ion cells and modules that are affected by local conditions of heat and materials; (2) use the 3D Li-ion battery thermal abuse 'reaction' model developed for cells to explore the impact of the location of internal short, its heating rate, and thermal properties of the cell; (3) continue to understand the mechanisms and interactions between heat transfer and chemical reactions during thermal runaway for Li-ion cells and modules; and (4) explore the use of the developed methodology to support the design of abuse-tolerant Li-ion battery systems.

Applicability of tungsten/EUROFER blanket module for the DEMO first wall

NASA Astrophysics Data System (ADS)

Igitkhanov, Yu.; Bazylev, B.; Landman, I.; Boccaccini, L.

2013-07-01

In this paper we analyse a sandwich-type blanket configuration of W/EUROFER for DEMO first wall under steady-state normal operation and off-normal conditions, such as vertical displacements and runaway electrons. The heat deposition and consequent erosion of the tungsten armour is modelled under condition of helium cooling of the first wall blanket module and by taking into account the conversion of the magnetic energy stored in the runaway electron current into heat through the ohmic dissipation of the return current induced in the metallic armour structure. It is shown that under steady-state DEMO operation the first wall sandwich type module will tolerate heat loads up to ˜14 MW/m2. It will also sustain the off-normal events, apart from the hot vertical displacement events, which will melt the tungsten armour surface.

Determination of hot-spot susceptibility of multistring photovoltaic modules in a central-station application

NASA Technical Reports Server (NTRS)

Gonzalez, C. C.; Weaver, R. W.; Ross, R. G., Jr.; Spencer, R.; Arnett, J. C.

1984-01-01

Part of the effort of the Jet Propulsion Laboratory (JPL) Flat-Plate Solar Array Project (FSA) includes a program to improve module and array reliability. A collaborative activity with industry dealing with the problem of hot-spot heating due to the shadowing of photovoltaic cells in modules and arrays containing several paralleled cell strings is described. The use of multiparallel strings in large central-station arrays introduces the likelihood of unequal current sharing and increased heating levels. Test results that relate power dissipated, current imbalance, cross-strapping frequency, and shadow configuration to hot-spot heating levels are presented. Recommendations for circuit design configurations appropriate to central-station applications that reduce the risk of hot-spot problems are offered. Guidelines are provided for developing hot-spot tests for arrays when current imbalance is a threat.

International Space Station (ISS) Soyuz Vehicle Descent Module Evaluation of Thermal Protection System (TPS) Penetration Characteristics

NASA Technical Reports Server (NTRS)

Davis, Bruce A.; Christiansen, Eric L.; Lear, Dana M.; Prior, Tom

2013-01-01

The descent module (DM) of the ISS Soyuz vehicle is covered by thermal protection system (TPS) materials that provide protection from heating conditions experienced during reentry. Damage and penetration of these materials by micrometeoroid and orbital debris (MMOD) impacts could result in loss of vehicle during return phases of the mission. The descent module heat shield has relatively thick TPS and is protected by the instrument-service module. The TPS materials on the conical sides of the descent module (referred to as backshell in this test plan) are exposed to more MMOD impacts and are relatively thin compared to the heat shield. This test program provides hypervelocity impact (HVI) data on materials similar in composition and density to the Soyuz TPS on the backshell of the vehicle. Data from this test program was used to update ballistic limit equations used in Soyuz TPS penetration risk assessments. The impact testing was coordinated by the NASA Johnson Space Center (JSC) Hypervelocity Impact Technology (HVIT) Group [1] in Houston, Texas. The HVI testing was conducted at the NASA-JSC White Sands Hypervelocity Impact Test Facility (WSTF) at Las Cruces, New Mexico. Figure

Overview of the NCC

NASA Technical Reports Server (NTRS)

Liu, Nan-Suey

2001-01-01

A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between then NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Glenn Research Center (LeRC), and Pratt & Whitney (P&W). The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration. The development of the NCC beta version was essentially completed in June 1998. Technical details of the NCC elements are given in the Reference List. Elements such as the baseline flow solver, turbulence module, and the chemistry module, have been extensively validated; and their parallel performance on large-scale parallel systems has been evaluated and optimized. However the scalar PDF module and the Spray module, as well as their coupling with the baseline flow solver, were developed in a small-scale distributed computing environment. As a result, the validation of the NCC beta version as a whole was quite limited. Current effort has been focused on the validation of the integrated code and the evaluation/optimization of its overall performance on large-scale parallel systems.

Heat source reconstruction from noisy temperature fields using a gradient anisotropic diffusion filter

NASA Astrophysics Data System (ADS)

Beitone, C.; Balandraud, X.; Delpueyo, D.; Grédiac, M.

2017-01-01

This paper presents a post-processing technique for noisy temperature maps based on a gradient anisotropic diffusion (GAD) filter in the context of heat source reconstruction. The aim is to reconstruct heat source maps from temperature maps measured using infrared (IR) thermography. Synthetic temperature fields corrupted by added noise are first considered. The GAD filter, which relies on a diffusion process, is optimized to retrieve as well as possible a heat source concentration in a two-dimensional plate. The influence of the dimensions and the intensity of the heat source concentration are discussed. The results obtained are also compared with two other types of filters: averaging filter and Gaussian derivative filter. The second part of this study presents an application for experimental temperature maps measured with an IR camera. The results demonstrate the relevancy of the GAD filter in extracting heat sources from noisy temperature fields.

Sound source localization identification accuracy: Envelope dependencies.

PubMed

Yost, William A

2017-07-01

Sound source localization accuracy as measured in an identification procedure in a front azimuth sound field was studied for click trains, modulated noises, and a modulated tonal carrier. Sound source localization accuracy was determined as a function of the number of clicks in a 64 Hz click train and click rate for a 500 ms duration click train. The clicks were either broadband or high-pass filtered. Sound source localization accuracy was also measured for a single broadband filtered click and compared to a similar broadband filtered, short-duration noise. Sound source localization accuracy was determined as a function of sinusoidal amplitude modulation and the "transposed" process of modulation of filtered noises and a 4 kHz tone. Different rates (16 to 512 Hz) of modulation (including unmodulated conditions) were used. Providing modulation for filtered click stimuli, filtered noises, and the 4 kHz tone had, at most, a very small effect on sound source localization accuracy. These data suggest that amplitude modulation, while providing information about interaural time differences in headphone studies, does not have much influence on sound source localization accuracy in a sound field.

Orion Heat Shield

NASA Image and Video Library

2015-05-06

ENGINEERS FROM AMES RESEARCH CENTER AND MARSHALL SPACE FLIGHT CENTER REMOVE AVCOAT SEGMENTS FROM THE SURFACE OF THE ORION HEAT SHIELD, THE PROTECTIVE SHELL DESIGNED TO HELP THE NEXT GENERATION CREW MODULE WITHSTAND THE HEAT OF ATMOSPHERIC REENTRY. THE HEAT SHIELD FLEW TO SPACE DURING THE EFT-1 FULL SCALL FLIGHT TEST OF ORION IN DECEMBER 2014

Thermal Design, Analysis, and Testing of the Quench Module Insert Bread Board

NASA Technical Reports Server (NTRS)

Breeding, Shawn; Khodabandeh, Julia

2002-01-01

Contents include the following: Quench Module Insert (QMI) science requirements. QMI interfaces. QMI design layout. QMI thermal analysis and design methodology. QMI bread board testing and instrumentation approach. QMI thermal probe design parameters. Design features for gradient measurement. Design features for heated zone measurements. Thermal gradient analysis results. Heated zone analysis results. Bread board thermal probe layout. QMI bread board correlation and performance. Summary and conclusions.

Development of a self contained heat rejection module, phase 2 and 3

NASA Technical Reports Server (NTRS)

Fleming, M. L.

1976-01-01

The fabrication and testing of a prototype deployable radiator system is described. Vapor compression with a conventional aircraft compressor yielded a net heat rejection effect at high environments while returning low temperature (10 F and 35 F) conditioned fluid to the payload thermal control system. The system is compatible with shuttle orbiter payloads, free flying experiment modules launched from the shuttle, or by another launch vehicle.

California heat waves: their spatial evolution, variation, and coastal modulation by low clouds

NASA Astrophysics Data System (ADS)

Clemesha, Rachel E. S.; Guirguis, Kristen; Gershunov, Alexander; Small, Ivory J.; Tardy, Alexander

2018-06-01

We examine the spatial and temporal evolution of heat waves through California and consider one of the key modulating factors of summertime coastal climate—coastal low cloudiness (CLC). Heat waves are defined relative to daytime maximum temperature (Tmax) anomalies after removing local seasonality and capture unseasonably warm events during May—September. California is home to several diverse climate regions and characteristics of extreme heat events are also variable throughout these regions. Heat wave events tend to be shorter, but more anomalously intense along the coast. Heat waves typically impact both coastal and inland regions, although there is more propensity towards coastally trapped events. Most heat waves with a strong impact across regions start at the coast, proceed inland, and weaken at the coast before letting up inland. Typically, the beginning of coastal heat waves are associated with a loss of CLC, followed by a strong rebound of CLC starting close to the peak in heat wave intensity. The degree to which an inland heat wave is expressed at the coast is associated with the presence of these low clouds. Inland heat waves that have very little expression at the coast tend to have CLC present and an elevated inversion base height compared with other heat waves.

Stationary Engineers Apprenticeship. Related Training Modules. 13.1-13.7 Pumps.

ERIC Educational Resources Information Center

Lane Community Coll., Eugene, OR.

This learning module, one in a series of 20 related training modules for apprentice stationary engineers, deals with pumps. Addressed in the individual instructional packages included in the module are the following topics: types, classifications, and applications of pumps; pump construction; procedures for calculating pump heat and pump flow;…

Millwright Apprenticeship. Related Training Modules. 10.1-10.5 Combustion.

ERIC Educational Resources Information Center

Lane Community Coll., Eugene, OR.

This packet, part of the instructional materials for the Oregon apprenticeship program for millwright training, contains five modules covering combustion. The modules provide information on the following topics: the combustion process, types of fuel, air and fuel gases, heat transfer, and combustion in wood. Each module consists of a goal,…

Stationary Engineers Apprenticeship. Related Training Modules. 16.1-16.5 Combustion.

ERIC Educational Resources Information Center

Lane Community Coll., Eugene, OR.

This learning module, one in a series of 20 related training modules for apprentice stationary engineers, deals with combustion. Addressed in the individual instructional packages included in the module are the following topics: the combustion process, types of fuel, air and flue gases, heat transfer during combustion, and wood combustion. Each…

Fitness-related differences in the rate of whole-body evaporative heat loss in exercising men are heat-load dependent.

PubMed

Lamarche, Dallon T; Notley, Sean R; Louie, Jeffrey C; Poirier, Martin P; Kenny, Glen P

2018-01-01

What is the central question of this study? Aerobic fitness modulates heat loss, but the heat-load threshold at which fitness-related differences in heat loss occur in young healthy men remains unclear. What is the main finding and its importance? We demonstrate using direct calorimetry that aerobic fitness modulates heat loss in a heat-load-dependent manner, with fitness-related differences occurring between young men who have low and high fitness when the heat load is ∼≥500 W. Although aerobic fitness has been known for some time to modulate heat loss, our findings define the precise heat-load threshold at which fitness-related differences occur. The effect of aerobic fitness (defined as rate of peak oxygen consumption) on heat loss during exercise is thought to be related to the level of heat stress. However, it remains unclear at what combined exercise and environmental (net) heat-load threshold these fitness-related differences occur. To identify this, we assessed whole-body heat exchange (dry and evaporative) by direct calorimetry in young (22 ± 3 years) men matched for physical characteristics with low (Low-fit; 39.8 ± 2.5 ml O 2  kg -1  min -1 ), moderate (Mod-fit; 50.9 ± 1.2 ml O 2  kg -1  min -1 ) and high aerobic fitness (High-fit; 62.0 ± 4.4 ml O 2  kg -1  min -1 ; each n = 8), during three 30 min bouts of cycling in dry heat (40°C, 12% relative humidity) at increasing rates of metabolic heat production of 300 (Ex1), 400 (Ex2) and 500 W (Ex3), each followed by a 15 min recovery period. Each group was exposed to a similar net heat load (metabolic plus ∼100 W dry heat gain; P = 0.83) during each exercise bout [∼400 (Ex1), ∼500 (Ex2) and ∼600 W (Ex3); P < 0.01]. Although evaporative heat loss was similar between groups during Ex1 (P = 0.33), evaporative heat loss was greater in the High-fit (Ex2, 466 ± 21 W; Ex3, 557 ± 26 W) compared with the Low-fit group (Ex2, 439 ± 22 W; Ex3, 511 ± 20 W) during Ex2 and Ex3 (P ≤ 0.03). Conversely, evaporative heat loss for the Mod-fit group did not differ from either the High-fit or Low-fit group during all exercise bouts (P ≥ 0.09). We demonstrate that aerobic fitness modulates heat loss in a heat-load-dependent manner, such that young, highly fit men display greater heat-loss capacity only at heat loads ∼≥500 W compared with their lesser trained counterparts. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Energy Conservation Curriculum for Secondary and Post-Secondary Students. Module 6: Hot Water Heating Conservation Opportunities.

ERIC Educational Resources Information Center

Navarro Coll., Corsicana, TX.

This module is the sixth in a series of eleven modules in an energy conservation curriculum for secondary and postsecondary vocational students. It is designed for use by itself or as part of a sequence of four modules on understanding utilities (see also modules 3, 5, and 7). The objective of this module is to train students in the recognition,…

Solid state lighting devices and methods with rotary cooling structures

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

Koplow, Jeffrey P.

Solid state lighting devices and methods for heat dissipation with rotary cooling structures are described. An example solid state lighting device includes a solid state light source, a rotating heat transfer structure in thermal contact with the solid state light source, and a mounting assembly having a stationary portion. The mounting assembly may be rotatably coupled to the heat transfer structure such that at least a portion of the mounting assembly remains stationary while the heat transfer structure is rotating. Examples of methods for dissipating heat from electrical devices, such as solid state lighting sources are also described. Heat dissipationmore » methods may include providing electrical power to a solid state light source mounted to and in thermal contact with a heat transfer structure, and rotating the heat transfer structure through a surrounding medium.« less

Method for welding an article and terminating the weldment within the perimeter of the article

NASA Technical Reports Server (NTRS)

Snyder, John H. (Inventor); Smashey, Russell W. (Inventor); Boerger, Eric J. (Inventor); Borne, Bruce L. (Inventor)

2000-01-01

An article is welded, as in weld repair of a defect, by positioning a weld lift-off block at a location on the surface of the article adjacent to the intended location of the end of the weldment on the surface of the article. The weld lift-off block has a wedge shape including a base contacting the surface of the article, and an upper face angled upwardly from the base from a base leading edge. A weld pool is formed on the surface of the article by directly heating the surface of the article using a heat source. The heat source is moved relative to the surface of the article and onto the upper surface of the weld lift-off block by crossing the leading edge of the wedge, without discontinuing the direct heating of the article by the heat source. The heating of the article with the heat source is discontinued only after the heat source is directly heating the upper face of the weld lift-off block, and not the article.

Contact Force Compensated Thermal Stimulators for Holistic Haptic Interfaces.

PubMed

Sim, Jai Kyoung; Cho, Young-Ho

2016-05-01

We present a contact force compensated thermal stimulator that can provide a consistent tempera- ture sensation on the human skin independent of the contact force between the thermal stimulator and the skin. Previous passive thermal stimulators were not capable of providing a consistent tem- perature on the human skin even when using identical heat source voltage due to an inconsistency of the heat conduction, which changes due to the force-dependent thermal contact resistance. We propose a force-based feedback method that monitors the contact force and controls the heat source voltage according to this contact force, thus providing consistent temperature on the skin. We composed a heat circuit model equivalent to the skin heat-transfer rate as it is changed by the contact forces; we obtained the optimal voltage condition for the constant skin heat-transfer rate independent of the contact force using a numerical estimation simulation tool. Then, in the experiment, we heated real human skin at the obtained heat source voltage condition, and investigated the skin heat transfer-rate by measuring the skin temperature at various times at different levels of contact force. In the numerical estimation results, the skin heat-transfer rate for the contact forces showed a linear profile in the contact force range of 1-3 N; from this profile we obtained the voltage equation for heat source control. In the experimental study, we adjusted the heat source voltage according to the contact force based on the obtained equation. As a result, without the heat source voltage control for the contact forces, the coefficients of variation (CV) of the skin heat-transfer rate in the contact force range of 1-3 N was found to be 11.9%. On the other hand, with the heat source voltage control for the contact forces, the CV of the skin heat-transfer rate in the contact force range of 1-3 N was found to be barely 2.0%, which indicate an 83.2% improvement in consistency compared to the skin heat-transfer rate without the heat source voltage control. The present technique provides a consistent temperature sensation on the human skin independent of the body movement environment; therefore, it has high potential for use in holistic haptic interfaces that have thermal displays.

Status of the Development of Low Cost Radiator for Surface Fission Power - II

NASA Technical Reports Server (NTRS)

Tarau, Calin; Maxwell, Taylor; Anderson, William G.; Wagner, Corey; Wrosch, Matthew; Briggs, Maxwell H.

2016-01-01

NASA Glenn Research Center (GRC) is developing fission power system technology for future Lunar and Martian surface power applications. The systems are envisioned in the 10 to 100kWe range and have an anticipated design life of 8 to 15 years with no maintenance. NASA GRC is currently setting up a 55 kWe non-nuclear system ground test in thermal-vacuum to validate technologies required to transfer reactor heat, convert the heat into electricity, reject waste heat, process the electrical output, and demonstrate overall system performance. The paper reports on the development of the heat pipe radiator to reject the waste heat from the Stirling convertors. Reducing the radiator mass, size, and cost is essential to the success of the program. To meet these goals, Advanced Cooling Technologies, Inc. (ACT) and Vanguard Space Technologies, Inc. (VST) are developing a single facesheet radiator with heat pipes directly bonded to the facesheet. The facesheet material is a graphite fiber reinforced composite (GFRC) and the heat pipes are titanium/water Variable Conductance Heat Pipes (VCHPs). By directly bonding a single facesheet to the heat pipes, several heavy and expensive components can be eliminated from the traditional radiator design such as, POCO"TM" foam saddles, aluminum honeycomb, and a second facesheet. As mentioned in previous papers by the authors, the final design of the waste heat radiator is described as being modular with independent GFRC panels for each heat pipe. The present paper reports on test results for a single radiator module as well as a radiator cluster consisting of eight integral modules. These tests were carried out in both ambient and vacuum conditions. While the vacuum testing of the single radiator module was performed in the ACT's vacuum chamber, the vacuum testing of the eight heat pipe radiator cluster took place in NASA GRC's vacuum chamber to accommodate the larger size of the cluster. The results for both articles show good agreement with the predictions and are presented in the paper.

Advanced radioisotope heat source for Stirling Engines

NASA Astrophysics Data System (ADS)

Dobry, T. J.; Walberg, G.

2001-02-01

The heat exchanger on a Stirling Engine requires a thermal energy transfer from a heat source to the engine through a very limited area on the heater head circumference. Designing an effective means to assure maximum transfer efficiency is challenging. A single General Purpose Heat Source (GPHS), which has been qualified for space operations, would satisfy thermal requirements for a single Stirling Engine that would produce 55 electrical watts. However, it is not efficient to transfer its thermal energy to the engine heat exchanger from its rectangular geometry. This paper describes a conceptual design of a heat source to improve energy transfer for Stirling Engines that may be deployed to power instrumentation on space missions. .

A solar receiver-storage modular cascade based on porous ceramic structures for hybrid sensible/thermochemical solar energy storage

NASA Astrophysics Data System (ADS)

Agrafiotis, Christos; de Oliveira, Lamark; Roeb, Martin; Sattler, Christian

2016-05-01

The current state-of-the-art solar heat storage concept in air-operated Solar Tower Power Plants is to store the solar energy provided during on-sun operation as sensible heat in porous solid materials that operate as recuperators during off-sun operation. The technology is operationally simple; however its storage capacity is limited to 1.5 hours. An idea for extending this capacity is to render this storage concept from "purely" sensible to "hybrid" sensible/ thermochemical one, via coating the porous heat exchange modules with oxides of multivalent metals for which their reduction/oxidation reactions are accompanied by significant heat effects, or by manufacturing them entirely of such oxides. In this way solar heat produced during on-sun operation can be used (in addition to sensibly heating the porous solid) to power the endothermic reduction of the oxide from its state with the higher metal valence to that of the lower; the thermal energy can be entirely recovered by the reverse exothermic oxidation reaction (in addition to sensible heat) during off-sun operation. Such sensible and thermochemical storage concepts were tested on a solar-irradiated receiver- heat storage module cascade for the first time. Parametric studies performed so far involved the comparison of three different SiC-based receivers with respect to their capability of supplying solar-heated air at temperatures sufficient for the reduction of the oxides, the effect of air flow rate on the temperatures achieved within the storage module, as well as the comparison of different porous storage media made of cordierite with respect to their sensible storage capacity.

Tunable heat transfer with smart nanofluids.

PubMed

Bernardin, Michele; Comitani, Federico; Vailati, Alberto

2012-06-01

Strongly thermophilic nanofluids are able to transfer either small or large quantities of heat when subjected to a stable temperature difference. We investigate the bistability diagram of the heat transferred by this class of nanofluids. We show that bistability can be exploited to obtain a controlled switching between a conductive and a convective regime of heat transfer, so as to achieve a controlled modulation of the heat flux.

Intracellular and extracellular expression of the major inducible 70kDa heat shock protein in experimental ischemia-reperfusion injury of the spinal cord.

PubMed

Awad, Hamdy; Suntres, Zacharias; Heijmans, John; Smeak, Daniel; Bergdall-Costell, Valerie; Christofi, Fievos L; Magro, Cynthia; Oglesbee, Michael

2008-08-01

Inflammatory responses exacerbate ischemia-reperfusion (IR) injury of spinal cord, although understanding of mediators is incomplete. The major inducible 70kDa heat shock protein (hsp70) is induced by ischemia and extracellular hsp70 (e-hsp70) can modulate inflammatory responses, but there is no published information regarding e-hsp70 levels in the cerebrospinal fluid (CSF) or serum as part of any neurological disease state save trauma. The present work addresses this deficiency by examining e-hsp70 in serum and CSF of dogs in an experimental model of spinal cord IR injury. IR injury of spinal cord caused hind limb paraplegia within 2-3 h that was correlated to lumbosacral poliomalacia with T cell infiltrates at 3 d post-ischemia. In this context, we showed a 5.2-fold elevation of e-hsp70 in CSF that was induced by ischemia and was sustained for the following 3 d observation interval. Plasma e-hsp70 levels were unaffected by IR injury, indicating e-hsp70 release from within the central nervous system. A putative source of this e-hsp70 was ependymal cells in the ischemic penumbra, based upon elevated i-hsp70 levels detected within these cells. Results warrant further investigation of e-hsp70's potential to modulate spinal cord IR injury.

Influence of convection at outer ceramic surfaces on the characterization of thermoelectric modules by impedance spectroscopy

NASA Astrophysics Data System (ADS)

Beltrán-Pitarch, Braulio; García-Cañadas, Jorge

2018-02-01

Impedance spectroscopy is a useful method for the characterization of thermoelectric (TE) modules. It can determine with high accuracy the module's dimensionless figure of merit (zT) as well as the average TE properties of the module's thermoelements. Interpretation of impedance results requires the use of a theoretical model (equivalent circuit), which provides the desired device parameters after a fitting is performed to the experimental results. Here, we extend the currently available equivalent circuit, only valid for adiabatic conditions, to account for the effect of convection at the outer surface of the module ceramic plates, which is the part of the device where convection is more prominent. This is performed by solving the heat equation in the frequency domain including convection heat losses. As a result, a new element (convection resistance) appears in the developed equivalent circuit, which starts to influence at mid-low frequencies, causing a decrease of the typically observed semicircle in the impedance spectrum. If this effect is not taken into account, an underestimation of the zT occurs when measurements are performed under room conditions. The theoretical model is validated by experimental measurements performed in a commercial module with and without vacuum. Interestingly, the use of the new equivalent circuit allows the determination of the convection heat transfer coefficient (h), if the module's Seebeck coefficient is known, and an impedance measurement in vacuum is performed, opening up the possibility to develop TE modules as h sensors. On the other hand, if h is known, all the properties of the module (zT, ohmic (internal) resistance, average Seebeck coefficient and average thermal conductivity of the thermoelements and thermal conductivity of the ceramics) can be obtained from one impedance measurement in vacuum and another measurement under room conditions.

Fitness-related differences in the rate of whole-body total heat loss in exercising young healthy women are heat-load dependent.

PubMed

Lamarche, Dallon T; Notley, Sean R; Poirier, Martin P; Kenny, Glen P

2018-03-01

What is the central question of this study? Aerobic fitness modulates heat loss, albeit the heat load at which fitness-related differences occur in young healthy women remains unclear. What is the main finding and its importance? We demonstrate using direct calorimetry that fitness modulates heat loss in a heat-load dependent manner, with differences occurring between young women of low and high fitness and matched physical characteristics when the metabolic heat load is at least 400 W in hot, dry conditions. Although fitness has been known for some time to modulate heat loss, our findings define the metabolic heat load at which fitness-related differences occur. Aerobic fitness has recently been shown to alter heat loss capacity in a heat-load dependent manner in young men. However, given that sex-related differences in heat loss capacity exist, it is unclear whether this response is consistent in women. We therefore assessed whole-body total heat loss in young (21 ± 3 years old) healthy women matched for physical characteristics, but with low (low-fit; 35.8 ± 4.5 ml O 2  kg -1  min -1 ) or high aerobic fitness (high-fit; 53.1 ± 5.1 ml O 2  kg -1  min -1 ; both n = 8; indexed by peak oxygen consumption), during three 30 min bouts of cycling performed at increasing rates of metabolic heat production of 250 (Ex1), 325 (Ex2) and 400 W (Ex3), each separated by a 15 min recovery, in hot, dry conditions (40°C, 11% relative humidity). Whole-body total heat loss (evaporative ± dry heat exchange) and metabolic heat production were measured using direct and indirect calorimetry, respectively. Body heat content was measured as the temporal summation of heat production and loss. Total heat loss did not differ during Ex1 (low-fit, 215 ± 16 W; high-fit, 231 ± 20 W; P > 0.05) and Ex2 (low-fit, 278 ± 15 W; high-fit, 301 ± 20 W; P > 0.05), but was lower in the low-fit (316 ± 21 W) compared with the high-fit women (359 ± 32 W) during Ex3 (P < 0.01). Consequently, the low-fit group stored 1.3-fold more heat (429 ± 61 kJ) throughout the three exercise bouts relative to the high-fit group (330 ± 113 kJ; P < 0.05). We show that aerobic fitness independently modulates heat loss capacity during exercise in hot, dry conditions in women separated by a peak oxygen consumption of ∼17 ml O 2  kg -1  min -1 starting at a metabolic heat load of 400 W. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Optical arc sensor using energy harvesting power source

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

Choi, Kyoo Nam, E-mail: knchoi@inu.ac.kr; Rho, Hee Hyuk, E-mail: rdoubleh0902@inu.ac.kr

Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arcmore » energy levels, with a resolution below 17 J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.« less

Optical arc sensor using energy harvesting power source

NASA Astrophysics Data System (ADS)

Choi, Kyoo Nam; Rho, Hee Hyuk

2016-06-01

Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

Energy performance of semi-transparent PV modules for applications in buildings

NASA Astrophysics Data System (ADS)

Fung, Yu Yan

Owing to the increasing awareness on energy conservation and environmental protection, building-integrated photovoltaic (BIPV) has been developed rapidly in the past decade. A number of research studies have been conducted on the energy performance of BIPV systems. However, most of the previous studies focused on the systems that incorporated with opaque type PV modules, little attention has been devoted to semi-transparent type PV modules, which have been commonly integrated in modern architectures. This thesis aims at evaluating the energy performance of the semi-transparent BIPV modules, including heat gains to the indoor environment, power generation from the PV modules and daylight utilization. Solar radiation intensity on PV module's surfaces is an essential parameter for assessing energy performance of the PV modules. Different slope solar radiation models are analyzed and compared. The model that best suits Hong Kong situations is selected for the further development of the energy performance of the BIPV modules. The optimum orientation and tilted angle are determined in the analysis. In addition to the solar radiation models, a detailed investigation on the heat gain through the semi-transparent BIPV modules is carried out in this study. A one-dimensional transient heat transfer model, the SPVHG model, for evaluating the thermal performance of the semi-transparent BIPV modules is developed. The SPVHG model considers in detail the energy that is transmitted, absorbed and reflected in each element of the BIPV modules such as solar cells and glass layers. A computer program of the model is written accordingly. By applying the SPVHG model, the heat gain through the semi-transparent BIPV module of any thickness can be determined for any solar irradiance level. The annual performance can also be assessed by inputting annual weather data to the model. In order to verify the SPVHG model, laboratory tests have been carried out on semi-transparent BIPV modules. A well-insulated calorimeter box and an adjustable steady-state type solar simulator which can provide up to 1600 W/m2 have been used in the tests. Energy that transmitted through the semi-transparent BIPV modules and entered the calorimeter box was evaluated. It was found that the experimental results and the simulated results support each other. The SPVHG model is validated and can be used for further studies. Other than heat transfer, power production and the daylight utilization are also the vital parts in the energy performance assessment of the semi-transparent BIPV module for applications in building facades. Power generation models of both opaque and semi-transparent BIPV modules are investigated in this study. In order to test the validity of the power generation model, measurements on a BIPV system of an existing building are carried out. The measurement results reveal a good validity of the power generation model. Only a minor modification to the model is required. The daylight utilization is evaluated by using an indoor illuminance model. The model estimates the mean internal illuminance on the working plane of a room when there is both sunlight and skylight. Consequently, the power saving due to the daylight utilization can be determined. By using the SPVHG model together with the power generation model and the indoor illuminance model, the energy performance, in terms of electricity benefit, of building facades that incorporated with semi-transparent BIPV modules is evaluated. Different scenarios are studied by changing various parameters such as the window to wall ratios, thickness and efficiency of the solar cells. The results show that the solar cells within the semi-transparent BIPV modules significantly reduce the solar heat gain and thus reduce the power consumption of air-conditioning systems. Taking into account the impacts of PV electricity generation and daylight utilization, the optimum solar cell area ratio in the PV modules varies from 0.7 to 0.9 for different window-to-wall ratios of the building facade. The largest net electricity benefit of the BIPV facade under the simulation conditions is around 120 kWh/m 2. The SPVHG model developed in this study is a precise model for calculating the amount of heat gains through the semi-transparent BIPV modules. By considering also the power generation and daylight utilization, the electricity benefit of different BIPV facade configurations can be simulated. This information should help engineers predict the cooling load due to the BIPV facade and thus review their designs for energy efficiency optimization. On the whole, the results of this study provide valuable reference to local engineers, designers and professionals for efficient BIPV facade applications.

Modeling and Simulation of the ITER First Wall/Blanket Primary Heat Transfer System

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

Ying, Alice; Popov, Emilian L

2011-01-01

ITER inductive power operation is modeled and simulated using a thermal-hydraulics system code (RELAP5) integrated with a 3-D CFD (SC-Tetra) code. The Primary Heat Transfer System (PHTS) functions are predicted together with the main parameters operational ranges. The control algorithm strategy and derivation are summarized as well. The First Wall and Blanket modules are the primary components of PHTS, used to remove the major part of the thermal heat from the plasma. The modules represent a set of flow channels in solid metal structure that serve to absorb the radiation heat and nuclear heating from the fusion reactions and tomore » provide shield for the vacuum vessel. The blanket modules are water cooled. The cooling is forced convective with constant blanket inlet temperature and mass flow rate. Three independent water loops supply coolant to the three blanket sectors. The main equipment of each loop consists of a pump, a steam pressurizer and a heat exchanger. A major feature of ITER is the pulsed operation. The plasma does not burn continuously, but on intervals with large periods of no power between them. This specific feature causes design challenges to accommodate the thermal expansion of the coolant during the pulse period and requires active temperature control to maintain a constant blanket inlet temperature.« less

Integrating Phase-Change Materials into Automotive Thermoelectric Generators

NASA Astrophysics Data System (ADS)

Klein Altstedde, Mirko; Rinderknecht, Frank; Friedrich, Horst

2014-06-01

Because the heat emitted by conventional combustion-engine vehicles during operation has highly transient properties, automotive thermoelectric generators (TEG) are intended for a particular operating state (design point). This, however, leads to two problems. First, whenever the combustion engine runs at low load, the maximum operating temperature cannot be properly utilised; second, a combustion engine at high load requires partial diversion of exhaust gas away from the TEG to protect the thermoelectric modules. An attractive means of stabilising dynamic exhaust behaviour (thereby keeping the TEG operating status at the design point for as long as possible) is use of latent heat storage, also known as phase-change materials (PCM). By positioning PCM between module and exhaust heat conduit, and choosing a material with a phase-change temperature matching the module's optimum operating temperature, it can be used as heat storage. This paper presents results obtained during examination of the effect of integration of latent heat storage on the potential of automotive TEG to convert exhaust heat. The research resulted in the development of a concept based on the initial integration idea, followed by proof of concept by use of a specially created prototype. In addition, the potential amount of energy obtained by use of a PCM-equipped TEG was calculated. The simulations indicated a significant increase in electrical energy was obtained in the selected test cycle.

Photonic Applications Using Electrooptic Optical Signal Processors

DTIC Science & Technology

2011-11-16

analog-to-digital conversion using a continuous wave multiwavelength source and phase modulation Author(s): Bortnik, B.J.; Fetterman, H.R. Source... multiwavelength source and phase modulation Bartosz J. Bortnik* and Harold R. Fetterman Department of Electrical Engineering, University of California Los...utilizing a cw multiwavelength source and phase modulation instead of a mode-locked laser is presented. The output of the cw multiwave- length source

Sub-picowatt/kelvin resistive thermometry for probing nanoscale thermal transport.

PubMed

Zheng, Jianlin; Wingert, Matthew C; Dechaumphai, Edward; Chen, Renkun

2013-11-01

Advanced instrumentation in thermometry holds the key for experimentally probing fundamental heat transfer physics. However, instrumentation with simultaneously high thermometry resolution and low parasitic heat conduction is still not available today. Here we report a resistive thermometry scheme with ~50 μK temperature resolution and ~0.25 pW/K thermal conductance resolution, which is achieved through schemes using both modulated heating and common mode noise rejection. The suspended devices used herein have been specifically designed to possess short thermal time constants and minimal attenuation effects associated with the modulated heating current. Furthermore, we have systematically characterized the parasitic background heat conductance, which is shown to be significantly reduced using the new device design and can be effectively eliminated using a "canceling" scheme. Our results pave the way for probing fundamental nanoscale thermal transport processes using a general scheme based on resistive thermometry.

The possibility of developing hybrid PV/T solar system

NASA Astrophysics Data System (ADS)

Dobrnjac, M.; Zivkovic, P.; Babic, V.

2017-05-01

An alternative and cost-effective solution to developing integrated PV system is to use hybrid photovoltaic/thermal (PV/T) solar system. The temperature of PV modules increases due to the absorbed solar radiation that is not converted into electricity, causing a decrease in their efficiency. In hybrid PV/T solar systems the reduction of PV module temperature can be combined with a useful fluid heating. In this paper we present the possibility of developing a new hybrid PV/T solar system. Hybrid PV/T system can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We developed PV/T prototype consisted of commercial PV module and thermal panel with our original solution of aluminium absorber with special geometric shapes. The main advantages of our combined PV/T system are: removing of heat from the PV panel; extending the lifetime of photovoltaic cells; excess of the removing heat from PV part is used to heat the fluid in the thermal part of the panel; the possibility of using on the roof and facade constructions because less weight.

Transient thermal characteristics of high-temperature SiC power module enhanced with Al-bump technology

NASA Astrophysics Data System (ADS)

Tanisawa, Hidekazu; Kato, Fumiki; Koui, Kenichi; Sato, Shinji; Watanabe, Kinuyo; Takahashi, Hiroki; Murakami, Yoshinori; Sato, Hiroshi

2018-04-01

In this paper, we demonstrate a mounting technology that improves the tolerance to transient power loss by adding a heat capacity near the device. Silicon carbide (SiC) power devices can operate at high temperatures, up to 250 °C, at which silicon (Si) power devices cannot. Therefore, it is possible to allow a large temperature difference between the device and ambient air. Thus, the size of a power converter equipped with an SiC power module is reduced by simplifying the cooling system. The temperature of the power module is important not only in the steady state, but in transient loads as well. Therefore, we developed the Al-bump flip-chip mounting technology to increase heat capacity near the device. With this proposed structure, the heat capacity per device increased by 1.7% compared with the total heat capacity of the conventional structure using wire bonding. The reduction in transient thermal impedance is observed from 0.003 to 3 s, and we confirmed that the transient thermal impedance is reduced very efficiently by 15% at the maximum, compared with the conventional structure.

A thermal control approach for a solar electric propulsion thrust subsystem

NASA Technical Reports Server (NTRS)

Maloy, J. E.; Oglebay, J. C.

1979-01-01

A thrust subsystem thermal control design is defined for a Solar Electric Propulsion System (SEPS) proposed for the comet Halley Flyby/comet Tempel 2 rendezvous mission. A 114 node analytic model, developed and coded on the systems improved numerical differencing analyzer program, was employed. A description of the resulting thrust subsystem thermal design is presented as well as a description of the analytic model and comparisons of the predicted temperature profiles for various SEPS thermal configurations that were generated using this model. It was concluded that: (1) a BIMOD engine system thermal design can be autonomous; (2) an independent thrust subsystem thermal design is feasible; (3) the interface module electronics temperatures can be controlled by a passive radiator and supplementary heaters; (4) maintaining heat pipes above the freezing point would require an additional 322 watts of supplementary heating power for the situation where no thrusters are operating; (5) insulation is required around the power processors, and between the interface module and the avionics module, as well as in those areas which may be subjected to solar heating; and (6) insulation behind the heat pipe radiators is not necessary.

Development and Results of a First Generation Least Expensive Approach to Fission: Module Tests and Results

NASA Technical Reports Server (NTRS)

Houts, Mike; Godfroy, Tom; Pederson, Kevin; Sena, J. Tom; VanDyke, Melissa; Dickens, Ricky; Reid, Bob J.; Martin, Jim

2000-01-01

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on the Module Unfueled Thermal-hydraulic Test (MUTT) article has been performed at the Marshall Space Flight Center. This paper discusses the results of these experiments and identifies future tests to be performed.

Smart Materials and Structures-Smart Wing. Volumes 1, 2, 3 and 4

DTIC Science & Technology

1998-12-01

repeatable fashion when heat is applied. Therefore, once the pre-twist is successfully applied and the tube is installed in the model, heating the...modules were operated and calibrated online by the PSI 8400 Control System. Because the transducer modules are extremely sensitive to temperature, a...again substantiates that adaptive features tend to support each other, though not necessarily in a completely linear fashion , and essentially provide a

The development of a high-capacity instrument module heat transport system, appendixes

NASA Technical Reports Server (NTRS)

1981-01-01

Data sheets provide temperature requirements for 82 individual instruments that are under development or planned for grouping on a space platform or pallet. The scientific objectives of these instrument packages are related to solar physics, space plasma physics, astronomy, high energy astrophysics, resources observations, environmental observations, materials processing, and life sciences. System specifications are given for a high capacity instrument module heat transport system to be used with future payloads.

Recovery - Apollo Spacecraft (S/C)-017

NASA Image and Video Library

1967-11-09

S67-49423 (9 Nov. 1967) --- The Apollo Spacecraft 017 Command Module, with flotation collar still attached, is hoisted aboard the USS Bennington, prime recovery ship for the Apollo 4 (Spacecraft 017/Saturn 501) unmanned, Earth-orbital space mission. The Command Module splashed down at 3:37 p.m. (EST), Nov. 9, 1967, 934 nautical miles northwest of Honolulu, Hawaii, in the mid-Pacific Ocean. Note charred heat shield caused by extreme heat of reentry.

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

NASA Technical Reports Server (NTRS)

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

1992-01-01

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

Spatial light modulator array with heat minimization and image enhancement features

DOEpatents

Jain, Kanti [Briarcliff Manor, NY; Sweatt, William C [Albuquerque, NM; Zemel, Marc [New Rochelle, NY

2007-01-30

An enhanced spatial light modulator (ESLM) array, a microelectronics patterning system and a projection display system using such an ESLM for heat-minimization and resolution enhancement during imaging, and the method for fabricating such an ESLM array. The ESLM array includes, in each individual pixel element, a small pixel mirror (reflective region) and a much larger pixel surround. Each pixel surround includes diffraction-grating regions and resolution-enhancement regions. During imaging, a selected pixel mirror reflects a selected-pixel beamlet into the capture angle of a projection lens, while the diffraction grating of the pixel surround redirects heat-producing unused radiation away from the projection lens. The resolution-enhancement regions of selected pixels provide phase shifts that increase effective modulation-transfer function in imaging. All of the non-selected pixel surrounds redirect all radiation energy away from the projection lens. All elements of the ESLM are fabricated by deposition, patterning, etching and other microelectronic process technologies.

Modeling of solar polygeneration plant

NASA Astrophysics Data System (ADS)

Leiva, Roberto; Escobar, Rodrigo; Cardemil, José

2017-06-01

In this work, a exergoeconomic analysis of the joint production of electricity, fresh water, cooling and process heat for a simulated concentrated solar power (CSP) based on parabolic trough collector (PTC) with thermal energy storage (TES) and backup energy system (BS), a multi-effect distillation (MED) module, a refrigeration absorption module, and process heat module is carried out. Polygeneration plant is simulated in northern Chile in Crucero with a yearly total DNI of 3,389 kWh/m2/year. The methodology includes designing and modeling a polygeneration plant and applying exergoeconomic evaluations and calculating levelized cost. Solar polygeneration plant is simulated hourly, in a typical meteorological year, for different solar multiple and hour of storage. This study reveals that the total exergy cost rate of products (sum of exergy cost rate of electricity, water, cooling and heat process) is an alternative method to optimize a solar polygeneration plant.

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

NASA Astrophysics Data System (ADS)

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

1992-07-01

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

Experimental Studies on the Flammability and Fire Hazards of Photovoltaic Modules

PubMed Central

Yang, Hong-Yun; Zhou, Xiao-Dong; Yang, Li-Zhong; Zhang, Tao-Lin

2015-01-01

Many of the photovoltaic (PV) systems on buildings are of sufficiently high voltages, with potential to cause or promote fires. However, research about photovoltaic fires is insufficient. This paper focuses on the flammability and fire hazards of photovoltaic modules. Bench-scale experiments based on polycrystalline silicon PV modules have been conducted using a cone calorimeter. Several parameters including ignition time (tig), mass loss, heat release rate (HRR), carbon monoxide (CO) and carbon dioxide (CO2) concentration, were investigated. The fire behaviours, fire hazards and toxicity of gases released by PV modules are assessed based on experimental results. The results show that PV modules under tests are inflammable with the critical heat flux of 26 kW/m2. This work will lead to better understanding on photovoltaic fires and how to help authorities determine the appropriate fire safety provisions for controlling photovoltaic fires. PMID:28793434

Experimental Studies on the Flammability and Fire Hazards of Photovoltaic Modules.

PubMed

Yang, Hong-Yun; Zhou, Xiao-Dong; Yang, Li-Zhong; Zhang, Tao-Lin

2015-07-09

Many of the photovoltaic (PV) systems on buildings are of sufficiently high voltages, with potential to cause or promote fires. However, research about photovoltaic fires is insufficient. This paper focuses on the flammability and fire hazards of photovoltaic modules. Bench-scale experiments based on polycrystalline silicon PV modules have been conducted using a cone calorimeter. Several parameters including ignition time ( t ig ), mass loss, heat release rate (HRR), carbon monoxide (CO) and carbon dioxide (CO₂) concentration, were investigated. The fire behaviours, fire hazards and toxicity of gases released by PV modules are assessed based on experimental results. The results show that PV modules under tests are inflammable with the critical heat flux of 26 kW/m². This work will lead to better understanding on photovoltaic fires and how to help authorities determine the appropriate fire safety provisions for controlling photovoltaic fires.

A neural network controller for hydronic heating systems of solar buildings.

PubMed

Argiriou, Athanassios A; Bellas-Velidis, Ioannis; Kummert, Michaël; André, Philippe

2004-04-01

An artificial neural network (ANN)-based controller for hydronic heating plants of buildings is presented. The controller has forecasting capabilities: it includes a meteorological module, forecasting the ambient temperature and solar irradiance, an indoor temperature predictor module, a supply temperature predictor module and an optimizing module for the water supply temperature. All ANN modules are based on the Feed Forward Back Propagation (FFBP) model. The operation of the controller has been tested experimentally, on a real-scale office building during real operating conditions. The operation results were compared to those of a conventional controller. The performance was also assessed via numerical simulation. The detailed thermal simulation tool for solar systems and buildings TRNSYS was used. Both experimental and numerical results showed that the expected percentage of energy savings with respect to a conventional controller is of about 15% under North European weather conditions.

A new regime of nanoscale thermal transport: Collective diffusion increases dissipation efficiency

DOE PAGES

Hoogeboom-Pot, Kathleen M.; Hernandez-Charpak, Jorge N.; Gu, Xiaokun; ...

2015-03-23

Understanding thermal transport from nanoscale heat sources is important for a fundamental description of energy flow in materials, as well as for many technological applications including thermal management in nanoelectronics and optoelectronics, thermoelectric devices, nanoenhanced photovoltaics, and nanoparticle-mediated thermal therapies. Thermal transport at the nanoscale is fundamentally different from that at the macroscale and is determined by the distribution of carrier mean free paths and energy dispersion in a material, the length scales of the heat sources, and the distance over which heat is transported. Past work has shown that Fourier’s law for heat conduction dramatically overpredicts the rate ofmore » heat dissipation from heat sources with dimensions smaller than the mean free path of the dominant heat-carrying phonons. In this work, we uncover a new regime of nanoscale thermal transport that dominates when the separation between nanoscale heat sources is small compared with the dominant phonon mean free paths. Surprisingly, the interaction of phonons originating from neighboring heat sources enables more efficient diffusive-like heat dissipation, even from nanoscale heat sources much smaller than the dominant phonon mean free paths. This finding suggests that thermal management in nanoscale systems including integrated circuits might not be as challenging as previously projected. In conclusion, we demonstrate a unique capability to extract differential conductivity as a function of phonon mean free path in materials, allowing the first (to our knowledge) experimental validation of predictions from the recently developed first-principles calculations.« less

A new regime of nanoscale thermal transport: Collective diffusion increases dissipation efficiency

NASA Astrophysics Data System (ADS)

Hoogeboom-Pot, Kathleen M.; Hernandez-Charpak, Jorge N.; Gu, Xiaokun; Frazer, Travis D.; Anderson, Erik H.; Chao, Weilun; Falcone, Roger W.; Yang, Ronggui; Murnane, Margaret M.; Kapteyn, Henry C.; Nardi, Damiano

2015-04-01

Understanding thermal transport from nanoscale heat sources is important for a fundamental description of energy flow in materials, as well as for many technological applications including thermal management in nanoelectronics and optoelectronics, thermoelectric devices, nanoenhanced photovoltaics, and nanoparticle-mediated thermal therapies. Thermal transport at the nanoscale is fundamentally different from that at the macroscale and is determined by the distribution of carrier mean free paths and energy dispersion in a material, the length scales of the heat sources, and the distance over which heat is transported. Past work has shown that Fourier's law for heat conduction dramatically overpredicts the rate of heat dissipation from heat sources with dimensions smaller than the mean free path of the dominant heat-carrying phonons. In this work, we uncover a new regime of nanoscale thermal transport that dominates when the separation between nanoscale heat sources is small compared with the dominant phonon mean free paths. Surprisingly, the interaction of phonons originating from neighboring heat sources enables more efficient diffusive-like heat dissipation, even from nanoscale heat sources much smaller than the dominant phonon mean free paths. This finding suggests that thermal management in nanoscale systems including integrated circuits might not be as challenging as previously projected. Finally, we demonstrate a unique capability to extract differential conductivity as a function of phonon mean free path in materials, allowing the first (to our knowledge) experimental validation of predictions from the recently developed first-principles calculations.

Advanced thermal energy management: A thermal test bed and heat pipe simulation

NASA Technical Reports Server (NTRS)

Barile, Ronald G.

1986-01-01

Work initiated on a common-module thermal test simulation was continued, and a second project on heat pipe simulation was begun. The test bed, constructed from surplus Skylab equipment, was modeled and solved for various thermal load and flow conditions. Low thermal load caused the radiator fluid, Coolanol 25, to thicken due to its temperature avoided by using a regenerator-heat-exchanger. Other possible solutions modeled include a radiator heater and shunting heat from the central thermal bus to the radiator. Also, module air temperature can become excessive with high avionics load. A second preoject concerning advanced heat pipe concepts was initiated. A program was written which calculates fluid physical properties, liquid and vapor pressure in the evaporator and condenser, fluid flow rates, and thermal flux. The program is directed to evaluating newer heat pipe wicks and geometries, especially water in an artery surrounded by six vapor channels. Effects of temperature, groove and slot dimensions, and wick properties are reported.

Unifying quantum heat transfer in a nonequilibrium spin-boson model with full counting statistics

NASA Astrophysics Data System (ADS)

Wang, Chen; Ren, Jie; Cao, Jianshu

2017-02-01

To study the full counting statistics of quantum heat transfer in a driven nonequilibrium spin-boson model, we develop a generalized nonequilibrium polaron-transformed Redfield equation with an auxiliary counting field. This enables us to study the impact of qubit-bath coupling ranging from weak to strong regimes. Without external modulations, we observe maximal values of both steady-state heat flux and noise power in moderate coupling regimes, below which we find that these two transport quantities are enhanced by the finite-qubit-energy bias. With external modulations, the geometric-phase-induced heat flux shows a monotonic decrease upon increasing the qubit-bath coupling at zero qubit energy bias (without bias). While under the finite-qubit-energy bias (with bias), the geometric-phase-induced heat flux exhibits an interesting reversal behavior in the strong coupling regime. Our results unify the seemingly contradictory results in weak and strong qubit-bath coupling regimes and provide detailed dissections for the quantum fluctuation of nonequilibrium heat transfer.

Orion Heat Shield Foam Blocks Prefitting

NASA Image and Video Library

2016-10-24

Tile blocks have been prefitted around the heat shield for the Orion crew module inside the Neil Armstrong Operations and Checkout Building high bay at NASA's Kennedy Space Center in Florida. The heat shield is one of the most critical elements of Orion and protects it and the future astronauts inside from searing temperatures experienced during reentry through Earth's atmosphere when they return home. For Exploration Mission-1, the top layer of Orion's heat shield that is primarily responsible for helping the crew module endure reentry heat will be composed of approximately 180 blocks, which are made of an ablative material called Avcoat designed to wear away as it heats up. Orion is being prepared for its flight on the agency's Space Launch System for Exploration Mission-1 in late 2018. Orion is the exploration spacecraft designed to carry astronauts to destinations not yet explored by humans, including an asteroid and NASA's Journey to Mars. It will have emergency abort capability, sustain the crew during space travel and provide safe re-entry from deep space return velocities.

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.

Thermal modulation for gas chromatography

NASA Technical Reports Server (NTRS)

Waite, J. Hunter (Inventor); Libardoni, Mark (Inventor); Stewart, Kristine (Inventor); Block, Bruce P. (Inventor); Sacks, Richard D. (Inventor); Hasselbrink, Ernest F. (Inventor)

2007-01-01

A thermal modulator device for gas chromatography and associated methods. The thermal modulator device includes a recirculating fluid cooling member, an electrically conductive capillary in direct thermal contact with the cooling member, and a power supply electrically coupled to the capillary and operable for controlled resistive heating of the capillary. The capillary can include more than one separate thermally modulated sections.

Heating and Air Conditioning. Auto Mechanics Curriculum Guide Module 9. Instructor's Guide.

ERIC Educational Resources Information Center

Hevel, David

This unit of instruction is one of a series of modules in the Missouri Auto Mechanics Curriculum Guide. The module's format was developed for competency-based teaching and testing. The module contains 11 units, each of which contains the following components: a competency profile, objective sheets, references, notes to the instructor, lesson…

Thermal Design to Meet Stringent Temperature Gradient/Stability Requirements of SWIFT BAT Detectors

NASA Technical Reports Server (NTRS)

Choi, Michael K.

2000-01-01

The Burst Alert Telescope (BAT) is an instrument on the National Aeronautics and Space Administration (NASA) SWIFT spacecraft. It is designed to detect gamma ray burst over a broad region of the sky and quickly align the telescopes on the spacecraft to the gamma ray source. The thermal requirements for the BAT detector arrays are very stringent. The maximum allowable temperature gradient of the 256 cadmium zinc telluride (CZT) detectors is PC. Also, the maximum allowable rate of temperature change of the ASICs of the 256 Detector Modules (DMs) is PC on any time scale. The total power dissipation of the DMs and Block Command & Data Handling (BCDH) is 180 W. This paper presents a thermal design that uses constant conductance heat pipes (CCHPs) to minimize the temperature gradient of the DMs, and loop heat pipes (LHPs) to transport the waste heat to the radiator. The LHPs vary the effective thermal conductance from the DMs to the radiator to minimize heater power to meet the heater power budget, and to improve the temperature stability. The DMs are cold biased, and active heater control is used to meet the temperature gradient and stability requirements.

Thermal modulation for gas chromatography

NASA Technical Reports Server (NTRS)

Block, Bruce P. (Inventor); Libardoni, Mark (Inventor); Stewart, Kristine (Inventor); Sacks, Richard D. (Inventor); Hasselbrink, Ernest F. (Inventor); Waite, J. Hunter (Inventor)

2007-01-01

A thermal modulator device for gas chromatography and associated methods. The thermal modulator device includes a cooling member, an electrically conductive capillary in direct thermal contact with the cooling member, and a power supply electrically coupled to the capillary and operable for controlled resistive heating of the capillary.

Thermal Performance Benchmarking: Annual Report

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

Feng, Xuhui

In FY16, the thermal performance of the 2014 Honda Accord Hybrid power electronics thermal management systems were benchmarked. Both experiments and numerical simulation were utilized to thoroughly study the thermal resistances and temperature distribution in the power module. Experimental results obtained from the water-ethylene glycol tests provided the junction-to-liquid thermal resistance. The finite element analysis (FEA) and computational fluid dynamics (CFD) models were found to yield a good match with experimental results. Both experimental and modeling results demonstrate that the passive stack is the dominant thermal resistance for both the motor and power electronics systems. The 2014 Accord power electronicsmore » systems yield steady-state thermal resistance values around 42- 50 mm to the 2nd power K/W, depending on the flow rates. At a typical flow rate of 10 liters per minute, the thermal resistance of the Accord system was found to be about 44 percent lower than that of the 2012 Nissan LEAF system that was benchmarked in FY15. The main reason for the difference is that the Accord power module used a metalized-ceramic substrate and eliminated the thermal interface material layers. FEA models were developed to study the transient performance of 2012 Nissan LEAF, 2014 Accord, and two other systems that feature conventional power module designs. The simulation results indicate that the 2012 LEAF power module has lowest thermal impedance at a time scale less than one second. This is probably due to moving low thermally conductive materials further away from the heat source and enhancing the heat spreading effect from the copper-molybdenum plate close to the insulated gate bipolar transistors. When approaching steady state, the Honda system shows lower thermal impedance. Measurement results of the thermal resistance of the 2015 BMW i3 power electronic system indicate that the i3 insulated gate bipolar transistor module has significantly lower junction-to-liquid thermal resistance as compared to the other systems. At a flow rate of 12 liters per minute, the thermal resistance of the i3 systems is only 30 percent of the Accord system and 15 percent of the LEAF system.« less

radEq Add-On Module for CFD Solver Loci-CHEM

NASA Technical Reports Server (NTRS)

McCloud, Peter

2013-01-01

Loci-CHEM to be applied to flow velocities where surface radiation due to heating from compression and friction becomes significant. The module adds a radiation equilibrium boundary condition to the computational fluid dynamics (CFD) code to produce accurate results. The module expanded the upper limit for accurate CFD solutions of Loci-CHEM from Mach 4 to Mach 10 based on Space Shuttle Orbiter Re-Entry trajectories. Loci-CHEM already has a very promising architecture and performance, but absence of radiation equilibrium boundary condition limited the application of Loci-CHEM to below Mach 4. The immediate advantage of the add-on module is that it allows Loci-CHEM to work with supersonic flows up to Mach 10. This transformed Loci-CHEM from a rocket engine- heritage CFD code with general subsonic and low-supersonic applications, to an aeroheating code with hypersonic applications. The follow-on advantage of the module is that it is a building block for additional add-on modules that will solve for the heating generated at Mach numbers higher than 10.

Thermoelectric generators incorporating phase-change materials for waste heat recovery from engine exhaust

DOEpatents

Meisner, Gregory P; Yang, Jihui

2014-02-11

Thermoelectric devices, intended for placement in the exhaust of a hydrocarbon fuelled combustion device and particularly suited for use in the exhaust gas stream of an internal combustion engine propelling a vehicle, are described. Exhaust gas passing through the device is in thermal communication with one side of a thermoelectric module while the other side of the thermoelectric module is in thermal communication with a lower temperature environment. The heat extracted from the exhaust gasses is converted to electrical energy by the thermoelectric module. The performance of the generator is enhanced by thermally coupling the hot and cold junctions of the thermoelectric modules to phase-change materials which transform at a temperature compatible with the preferred operating temperatures of the thermoelectric modules. In a second embodiment, a plurality of thermoelectric modules, each with a preferred operating temperature and each with a uniquely-matched phase-change material may be used to compensate for the progressive lowering of the exhaust gas temperature as it traverses the length of the exhaust pipe.

Reduction of conditioned pain modulation in humans by naltrexone: an exploratory study of the effects of pain catastrophizing

PubMed Central

Goodin, Burel; Kindler, Lindsay L.; Caudle, Robert M.; Edwards, Robert R.; Gravenstein, Nikolaus; Riley, Joseph L.; Fillingim, Roger B.

2013-01-01

The current study tested the hypothesis that conditioned pain modulation is mediated by the release of endogenous opioids with a placebo-controlled (sugar pill) study of naltrexone (50 mg) in 33 healthy volunteers over two counter-balanced sessions. Pain modulation consisted of rating of heat pain (palm) during concurrent cold water immersion (foot). Compared to baseline heat pain ratings, concurrent foot immersion lowered pain intensity ratings, which suggests an inhibitory effect, was reduced with naltrexone, suggesting at least partial dependence of inhibition on endogenous opioids. An exploratory analysis revealed that individual differences in catastrophizing moderated the effects of naltrexone; endogenous opioid blockade abolished modulation in subjects lower in catastrophizing while modulation was unaffected by naltrexone among high catastrophizers. The results suggest a role of endogenous opioids in endogenous analgesia, but hint that multiple systems might contribute to conditioned pain modulation, and that these systems might be differentially activated as a function of individual differences in responses to pain. PMID:22534819

Absorption sensor for CO in combustion gases using 2.3 µm tunable diode lasers

NASA Astrophysics Data System (ADS)

Chao, X.; Jeffries, J. B.; Hanson, R. K.

2009-11-01

Tunable diode laser absorption spectroscopy of CO was studied in the controlled laboratory environments of a heated cell and a combustion exhaust rig. Two absorption lines, R(10) and R(11) in the first overtone band of CO near 2.3 µm, were selected from a HITRAN simulation to minimize interference from water vapor at a representative combustion exhaust temperature (~1200 K). The linestrengths and collision broadening coefficients for these lines were measured in a heated static cell. This database was then used in a comparative study of direct absorption and wavelength-modulation absorption. CO concentration measurements using scanned-wavelength direct absorption (DA) and wavelength modulation with the second-harmonic signal normalized by the first-harmonic signal (WMS-2f/1f) all agreed with those measured by a conventional gas sampling analyzer over the range from <10 ppm to 2.3%. As expected, water vapor was found to be the dominant source of background interference for CO detection in combustion flows at high temperatures. Water absorption was measured to a high spectral resolution within the wavelength region 4295-4301 cm-1 at 1100 K, and shown to produce <10 ppm level interference for CO detection in combustion exhausts at temperatures up to 1200 K. We found that the WMS-2f/1f strategy avoids the need for WMS calibration measurements but requires characterization of the wavelength and injection-current intensity modulation of the specific diode laser. We conclude that WMS-2f/1f using the selected R(10) or R(11) transitions in the CO overtone band holds good promise for sensitive in situ detection of ppm-level CO in combustion flows, with high resistance to interference absorption from H2O.

Development of Flow Boiling and Condensation Experiment on the International Space Station- Normal and Low Gravity Flow Boiling Experiment Development and Test Results

NASA Technical Reports Server (NTRS)

Nahra, Henry K.; Hall, Nancy R.; Hasan, Mohammad M.; Wagner, James D.; May, Rochelle L.; Mackey, Jeffrey R.; Kolacz, John S.; Butcher, Robert L.; Frankenfield, Bruce J.; Mudawar, Issam;

Pyrolysis reactor and fluidized bed combustion chamber

DOEpatents

Green, Norman W.

1981-01-06

A solid carbonaceous material is pyrolyzed in a descending flow pyrolysis reactor in the presence of a particulate source of heat to yield a particulate carbon containing solid residue. The particulate source of heat is obtained by educting with a gaseous source of oxygen the particulate carbon containing solid residue from a fluidized bed into a first combustion zone coupled to a second combustion zone. A source of oxygen is introduced into the second combustion zone to oxidize carbon monoxide formed in the first combustion zone to heat the solid residue to the temperature of the particulate source of heat.

Buoyancy Effects in Strongly-Pulsed, Turbulent Diffusion Flames

NASA Technical Reports Server (NTRS)

Hermanson, J. C.; Johari, H.; Ghaem-Maghami, E.; Stocker, D. P.; Hegde, U. G.

2004-01-01

The objective of this experiment is to better understand the combustion behavior of pulsed, turbulent diffusion flames by conducting experiments in microgravity. The fuel jet is fully-modulated (i.e., completely shut off between pulses) by an externally controlled valve system leading to enhanced fuel/air mixing compared to acoustically excited or partially-modulated jets. Experiments are conducted both in laboratories at UW and WPI and in the GRC 2.2s Drop Tower. A single fuel nozzle with diameter d = 2 mm is centered in a combustor 20 20 cm in cross section and 67 cm in height. The gaseous fuel flow (ethylene or a 50/50 ethylene/nitrogen mixture by volume) is fully-modulated by a fast-response solenoid valve with injection times from tau = 4 to tau = 300 ms. The nominal Reynolds number based on the fuel velocity during injection, U(sub jet), is 5,000. A slow oxidizer co-flow properly ventilates the flame and an electrically heated wire loop serves as a continuous ignition source. Diagnostic techniques include video imaging, fine-wire thermocouples and thermopile radiometers, and gas sampling and standard emissions instruments (the last in the laboratory only).