Testing and performance simulation of an air- cooled thermoelectric module
Tubular compact air cooled thermoelectric module endurance and performance tests and computer simulation for space reactor power system
Merrifield, D. V.↗
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Current Pulses Momentarily Enhance Thermoelectric Cooling
The rates of cooling afforded by thermoelectric (Peltier) devices can be increased for short times by applying pulses of electric current greater than the currents that yield maximum steady-state cooling. It has been proposed to utilize such momentary enhancements of cooling in applications in which diode lasers and other semiconductor devices are required to operate for times of the order of milliseconds at temperatures too low to be easily obtainable in the steady state. In a typical contemplated application, a semiconductor device would be in contact with the final (coldest) somewhat taller stage of a multistage thermoelectric cooler. Steady current would be applied to the stages to produce steady cooling. Pulsed current would then be applied, enhancing the cooling of the top stage momentarily. The principles of operation are straightforward: In a thermoelectric device, the cooling occurs only at a junction at one end of the thermoelectric legs, at a rate proportional to the applied current. However, Joule heating occurs throughout the device at a rate proportional to the current squared. Hence, in the steady state, the steady temperature difference that the device can sustain increases with current only to the point beyond which the Joule heating dominates. If a pulse of current greater than the optimum current (the current for maximum steady cooling) is applied, then the junction becomes momentarily cooled below its lowest steady temperature until thermal conduction brings the resulting pulse of Joule heat to the junction and thereby heats the junction above its lowest steady temperature. A theoretical and experimental study of such transient thermoelectric cooling followed by transient Joule heating in response to current pulses has been performed. The figure presents results from one of the experiments. The study established the essential parameters that characterize the pulse cooling effect, including the minimum temperature achieved, the maximum temperature overshoot, the time to reach minimum temperature, the time while cooled, and the time between pulses. It was found that at large pulse amplitude, the amount of pulse supercooling is about a fourth of the maximum steady-state temperature difference. For the particular thermoelectric device used in one set of the experiments, the practical optimum pulse amplitude was found to be about 3 times the optimum steady-state current. In a further experiment, a pulse cooler was integrated into a small commercial thermoelectric threestage cooler and found to provide several degrees of additional cooling for a time long enough to operate a semiconductor laser in a gas sensor.
Snyder, G. Jeffrey↗
Improved thermoelectrically cooled quartz crystal microbalance
Design changes in the thermoelectrically-cooled quartz microbalance, which is used to monitor surface contamination in space simulation chambers, is described in terms of its extended temperature range, increased temperature control, mass sensitivity, and cooling power. The mass sensor uses 20 MHz quartz crystals having a sensitivity of 8.8 x 10 to the minus tenth power g/sq cm - Hz. The crystals are optically polished, metal plated, and overplated with magnesium fluoride to simulate an optical surface. The microbalance temperature circuitry is designed to readout and control surface temperature between 100 C and minus 59 C to plus or minus 0.5 C, and readout only temperature between minus 60 C and minus 199 C using auxiliary liquid nitrogen cooling. Data is included on the measurement of oil contamination of surfaces as a function of temperature in space simulation chambers.
D. McKeown↗
Improved Thermoelectrically Cooled Laser-Diode Assemblies
Cooling decreases wavelength and increases efficiency and lifetime. Two improved thermoelectrically cooled laser-diode assemblies incorporate commercial laser diodes providing combination of both high wavelength stability and broad wavelength tuning which are broadly tunable, highly stable devices for injection seeding of pulsed, high-power tunable alexandrite lasers used in lidar remote sensing of water vapor at wavelengths in vicinity of 727 nanometers. Provide temperature control needed to take advantage of tunability of commercial AlGaAs laser diodes in present injection-seeding application.
Glesne, Thomas R.↗
Half-Heusler alloys as emerging high power density thermoelectric cooling materials
Abstract To achieve optimal thermoelectric performance, it is crucial to manipulate the scattering processes within materials to decouple the transport of phonons and electrons. In half-Heusler (hH) compounds, selective defect reduction can significantly improve performance due to the weak electron-acoustic phonon interaction. This study utilized Sb-pressure controlled annealing process to modulate the microstructure and point defects of Nb 0.55 Ta 0.40 Ti 0.05 FeSb compound, resulting in a 100% increase in carrier mobility and a maximum power factor of 78 µW cm −1 K −2 , approaching the theoretical prediction for NbFeSb single crystal. This approach yielded the highest average zT of ~0.86 among hH in the temperature range of 300-873 K. The use of this material led to a 210% enhancement in cooling power density compared to Bi 2 Te 3 -based devices and a conversion efficiency of 12%. These results demonstrate a promising strategy for optimizing hH materials for near-room-temperature thermoelectric applications.
36 MATERIALS SCIENCE↗
Study of thermoelectric cooling of electronic equipment Final report
Thermoelectric coolers for electronic equipment
Source record↗
Thermoelectrically cooled cloud physics expansion chamber
The design and fabrication of a thermoelectric chiller for use in chilling a liquid reservoir is described. Acceptance test results establish the accuracy of the thermal model and predict the unit performance under various conditions required by the overall spacelab program.
Buist, R. J.↗
Thermoelectrically-cooled quartz microbalance
Temperature of microbalance can be maintained at ambient temperature or held at some other desired temperature. Microbalance has tow-stage thermoelectric device that controls temperature of quartz crystal. Heat can be pumped to or from balance by Peltier effect.
Mckeown, D.↗
Thermoelectrically-cooled variable-temperature probe
Variable-temperature probe for electron spectroscopy requires no cryogenic liquids or resistance heating elements. Device consists of heat sink, probe tip, and nickel-plated copper body which resists oxidation and transfers heat efficiently between tip and heat sink.
Kelso, R. M.↗
Lunar stone saw
This project addresses the problem of cutting lunar stones into blocks to be used to construct shelters to protect personnel and equipment from harmful solar radiation. This plant will manufacture 6 in x 1 ft x 2 ft blocks and will be located near the south pole to allow it to be in the shade at all times. This design uses a computer controlled robot, a boulder handler that uses hydraulics for movement, a computer system that used 3-D vision to determine the size of boulders, a polycrystalline diamond tipped saw blade that utilizes radiation for cooling, and a solar tower to collect solar energy. Only two electric motors are used in this plant because of the heavy weight of electric motors and the problem of cooling them. These two motors will be cooled by thermoelectric cooling. All other motors and actuators are to be hydraulic. The architectural design for the building as well as the conceptual design of the machines for cutting the blocks are described.
Clark, Tom↗
Thermoelectric Devices Cool, Power Electronics
Nextreme Thermal Solutions Inc., based in Research Triangle Park, North Carolina, licensed thermoelectric technology from NASA s Jet Propulsion Laboratory. This has allowed the company to develop cutting edge, thin-film thermoelectric coolers that effective remove heat generated by increasingly powerful and tightly packed microchip components. These solid-state coolers are ideal solutions for applications like microprocessors, laser diodes, LEDs, and even potentially for cooling the human body. Nextreme s NASA technology has also enabled the invention of thermoelectric generators capable of powering technologies like medical implants and wireless sensor networks.
Source record↗
Radioisotope thermoelectric generator cooling in the Shuttle bay
The paper describes a Shuttle-integrated radioisotope thermoelectric generator (RTG) that consists primarily of a pump package and plumbing connected directly to the Shuttle payload heat exchanger. The RTG utilizes on-board water evaporative cooling capability, which is normally used for ascent, entry, and for supplementing the radiators. Attention is given to the RTG cooling concepts which include: (1) an active thermal cooling system (ATCS), where two Freon-21 loops operate simultaneously to transport heat from the Orbiter subsystem and payloads through liquid-to-liquid heat exchangers and pin-fin coldplates to four heat sinks, and (2) an atmosphere revitalization system (ARS) which provides for thermal, pressure, and contaminate control of the crew cabin and its equipment. The use of a payload heat exchanger to reduce weight, cost and complexity associated with an independent cooling system was investigated in detail.
Stimpson, L. D.↗
Cooling radioisotope thermoelectric generators in the Shuttle
Radioisotope thermoelectric generators (RTG) to be used on future spacecraft and launched by the Shuttle must be cooled from the time they are installed and enclosed until the spacecraft is deployed from the Shuttle. A special Cooling Kit maintains their temperature well below critical by circulating water through the coils soldered to them and through a heat exchanger that boils water and externally discharges the resulting steam. The RTG Cooling Kit, including its support frame, if fully charged with about 64 kg of evaporation water, will increase the Shuttle launch mass by about 200 kg.
Norman, R. M.↗
Development of improved thermoelectric mater- ials for spacecraft applications final summary report, 29 jun. 1964 - 29 jun. 1965
Thermoelectric materials for spacecraft applications - optimization of bismuth-antimony alloys and ag-sb-fe-te-se system alloys for thermoelectric cooling in space environment
THERMOELECTRIC COOLING↗
Large area space qualified thermoelectrically (TE) cooled HgCdTe MW photovoltaic detectors for the Halogen Occultation Experiment (HALOE)
Large-area, HgCdTe MW photovoltaic detectors have been developed for the NASA-HALOE instrument scheduled for operation on the Upper Atmospheric Research Satellite. The photodiodes will be TE-cooled and were designed to operate in the 5.1-5.4 micron band at 185 K to measure nitric oxide concentrations in the atmosphere. The active area required 15 micron thick devices and a full backside common contact. Reflections from the backside contact doubled the effective thickness of the detectors. Optical interference from reflections was eliminated with a dual layer front surface A/R coating. Bakeout reliability was optimized by having Au metallization for both n and p interconnects. Detailed performance data and a model for the optical stack are presented.
Norton, P. W.↗
Cooling device featuring thermoelectric and diamond materials for temperature control of heat-dissipating devices
A cooling device for lowering the temperature of a heat-dissipating device. The cooling device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with the heat-dissipating device. During operation, heat flows from the heat-dissipating device into the heat-conducting substrate, where it is spread out over a relatively large area. A thermoelectric cooling material (e.g., a Bi.sub.2 Te.sub.3 -based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. Application of electrical power to the thermoelectric material drives the thermoelectric material to pump heat into a second heat-conducting substrate which, in turn, is attached to a heat sink.
Vandersande, Ian W.↗
Design and testing of an aerospace dew point hygrometer Final report
Thermoelectrically cooled miniature dew point hygrometer system for spacecraft instrumentation systems
THERMOELECTRIC COOLING↗
Thermocooling of GMR Sensors
A thermoelectrically cooled GMR sensor having a first thermoelectric layer with an array of nanowires, wherein the nanowires include a diameter of about 1 nanometer to about 1000 nanometers. A plurality of alternating layers of magnetic and nonmagnetic material are positioned over and extend the nanowires to form a GMR assembly. A second thermoelectric layer is positioned over the GMR assembly and extends the nanowires, such that the nanowires have a length of between about 100 nanometers and about 500 microns. Conductors are placed in contact with the first and second thermoelectric layers for connecting the thermoelectric layers to a voltage source.
Davis, Despina↗