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1

Development of Next Generation Segmented Thermoelectric Radioisotope Power Systems  

NASA Astrophysics Data System (ADS)

Radioisotope thermoelectric generators have been used for space-based applications since 1961 with a total of 22 space missions that have successfully used RTGs for electrical power production. The key advantages of radioisotope thermoelectric generators (RTGs) are their long life, robustness, compact size, and high reliability. Thermoelectric converters are easily scalable, and possess a linear current-voltage curve, making power generation easy to control via a shunt regulator and shunt radiator. They produce no noise, vibration or torque during operation. These properties have made RTGs ideally suitable for autonomous missions in the extreme environments of outer space and on planetary surfaces. More advanced radioisotope power systems (RPS) with higher specific power (W/kg) and/or power output are desirable for future NASA missions, including the Europa Geophysical Orbiter mission. For the past few years, the Jet Propulsion Laboratory (JPL) has been developing more efficient thermoelectric materials and has demonstrated significant increases in the conversion efficiency of high temperature thermocouples, up to 14% when operated across a 975K to 300K temperature differential. In collaboration with NASA Glenn Research Center, universities (USC and UNM), Ceramic and Metal Composites Corporation and industrial partners, JPL is now planning to lead the research and development of advanced thermoelectric technology for integration into the next generations of RPS. Preliminary studies indicate that this technology has the potential for improving the RPS specific power by more than 50% over the current state-of-the-art multi-mission RTG being built for the Mars Science Laboratory mission. A second generation advanced RPS is projected at more than doubling the specific power.

Fleurial, J.; Caillat, T.; Ewell, R. C.

2005-12-01

2

Development and optimization of a stove-powered thermoelectric generator  

NASA Astrophysics Data System (ADS)

Almost a third of the world's population still lacks access to electricity. Most of these people use biomass stoves for cooking which produce significant amounts of wasted thermal energy, but no electricity. Less than 1% of this energy in the form of electricity would be adequate for basic tasks such as lighting and communications. However, an affordable and reliable means of accomplishing this is currently nonexistent. The goal of this work is to develop a thermoelectric generator to convert a small amount of wasted heat into electricity. Although this concept has been around for decades, previous attempts have failed due to insufficient analysis of the system as a whole, leading to ineffective and costly designs. In this work, a complete design process is undertaken including concept generation, prototype testing, field testing, and redesign/optimization. Detailed component models are constructed and integrated to create a full system model. The model encompasses the stove operation, thermoelectric module, heat sinks, charging system and battery. A 3000 cycle endurance test was also conducted to evaluate the effects of operating temperature, module quality, and thermal interface quality on the generator's reliability, lifetime and cost effectiveness. The results from this testing are integrated into the system model to determine the lowest system cost in $/Watt over a five year period. Through this work the concept of a stove-based thermoelectric generator is shown to be technologically and economically feasible. In addition, a methodology is developed for optimizing the system for specific regional stove usage habits.

Mastbergen, Dan

3

Modular Isotopic Thermoelectric Generator  

SciTech Connect

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 a 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. The resultant design is highly modular, consisting of standard RTG slices, each producing ~24 watts at the desired output voltage of 28 volt. Thus, the design could be adapted to various space missions over a wide range of power levels, with little or no redesign. Each RTG slice consists of a 250-watt heat source module, eight multicouple thermoelectric modules, and standard sections of insulator, housing, radiator fins, and electrical circuit. The design makes it possible to check each thermoelectric module for electrical performance, thermal contact, leaktightness, and performance stability, after the generator is fully assembled; and to replace any deficient modules without disassembling the generator or perturbing the others. The RTG end sections provide the spring-loaded supports required to hold the free-standing heat source stack together during launch vibration. Details analysis indicates that the design offers a substantial improvement in specific power over the present generator of RTGs, using the same heat source modules. There are three copies in the file.

Schock, Alfred

1981-04-03

4

Solar thermoelectric generators  

NASA Technical Reports Server (NTRS)

The methods, the findings and the conclusions of a study for the design of a Solar Thermoelectric Generator (STG) intended for use as a power source for a spacecraft orbiting the planet Mercury are discussed. Several state-of-the-art thermoelectric technologies in the intended application were considered. The design of various STG configurations based on the thermoelectric technology selected from among the various technologies was examined in detail and a recommended STG design was derived. The performance characteristics of the selected STG technology and associated design were studied in detail as a function of the orbital characteristics of the STG in Mercury and throughout the orbit of Mercury around the sun.

1977-01-01

5

Superconducting thermoelectric generator  

DOEpatents

Thermoelectricity is produced by applying a temperature differential to dissimilar electrically conducting or semiconducting materials, thereby producing a voltage that is proportional to the temperature difference. Thermoelectric generators use this effect to directly convert heat into electricity; however, presently-known generators have low efficiencies due to the production of high currents which in turn cause large resistive heating losses. Some thermoelectric generators operate at efficiencies between 4% and 7% in the 800{degrees} to 1200{degrees}C range. According to its major aspects and bradly stated, the present invention is an apparatus and method for producing electricity from heat. In particular, the invention is a thermoelectric generator that juxtaposes a superconducting material and a semiconducting material - so that the superconducting and the semiconducting materials touch - to convert heat energy into electrical energy without resistive losses in the temperature range below the critical temperature of the superconducting material. Preferably, an array of superconducting material is encased in one of several possible configurations within a second material having a high thermal conductivity, preferably a semiconductor, to form a thermoelectric generator.

Metzger, J.D.; El-Genk, M.S.

1994-01-01

6

Superconducting thermoelectric generator  

DOEpatents

An apparatus and method for producing electricity from heat. The present invention is a thermoelectric generator that uses materials with substantially no electrical resistance, often called superconductors, to efficiently convert heat into electrical energy without resistive losses. Preferably, an array of superconducting elements is encased within a second material with a high thermal conductivity. The second material is preferably a semiconductor. Alternatively, the superconducting material can be doped on a base semiconducting material, or the superconducting material and the semiconducting material can exist as alternating, interleaved layers of waferlike materials. A temperature gradient imposed across the boundary of the two materials establishes an electrical potential related to the magnitude of the temperature gradient. The superconducting material carries the resulting electrical current at zero resistivity, thereby eliminating resistive losses. The elimination of resistive losses significantly increases the conversion efficiency of the thermoelectric device.

Metzger, J.D.; El-Genk, M.S.

1996-01-01

7

A portable solar thermoelectric generator  

Microsoft Academic Search

A new design, locally manufactured, solar powered thermoelectric generator is proposed. The system consists of two subsystems, namely; the solar collector and the thermoelectric module. The solar collector is an elliptic paraboloia dish 1.2 m in diameter which consists of twenty segments assembled together. The dish is carried on a simple stand which enables manual tracking of the Sun. The

Sofrata

1983-01-01

8

Thermoelectric power generation for battery charging  

SciTech Connect

Thermoelectric generators use the Seebeck effect to produce electrical power from a temperature difference caused by heat energy flow. In this paper the principle of using thermoelectrically converted heat energy for powering portable electronic equipment or charging its battery has been investigated for a lap-top computer. The thermoelectric battery charger developed, consists of a thermoelectric battery charger developed, consists of a thermoelectric converter system, powered from butane gas, and a dc-to-dc boost up converter. Both the sub-assemblies are designed using computer models and constructed. The unit produces an output power of 5 watts which doubles the life of the lap-top computer`s internal batteries.

Rahman, M. [Bangladesh Univ. of Engineering and Technology, Dhaka (Bangladesh); Shuttleworth, R. [Univ. of Manchester (United Kingdom). Electrical Engineering Lab.

1995-12-31

9

Thermoelectric generator for motor vehicle  

SciTech Connect

A thermoelectric generator is described for producing electric power for a motor vehicle from the heat of the exhaust gases produced by the engine of the motor vehicle. The exhaust gases 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. 8 figs.

Bass, J.C.

1997-04-29

10

Thermoelectric generator for motor vehicle  

DOEpatents

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.

Bass, John C. (6121 La Pintra Dr., La Jolla, CA 92037)

1997-04-29

11

Thermoelectric Energy Conversion: Future Directions and Technology Development Needs  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews the process of thermoelectric energy conversion along with key technology needs and challenges. The topics include: 1) The Case for Thermoelectrics; 2) Advances in Thermoelectrics: Investment Needed; 3) Current U.S. Investment (FY07); 4) Increasing Thermoelectric Materials Conversion Efficiency Key Science Needs and Challenges; 5) Developing Advanced TE Components & Systems Key Technology Needs and Challenges; 6) Thermoelectrics; 7) 200W Class Lightweight Portable Thermoelectric Generator; 8) Hybrid Absorption Cooling/TE Power Cogeneration System; 9) Major Opportunities in Energy Industry; 10) Automobile Waste Heat Recovery; 11) Thermoelectrics at JPL; 12) Recent Advances at JPL in Thermoelectric Converter Component Technologies; 13) Thermoelectrics Background on Power Generation and Cooling Operational Modes; 14) Thermoelectric Power Generation; and 15) Thermoelectric Cooling.

Fleurial, Jean-Pierre

2007-01-01

12

SNAP-III--THERMOELECTRIC GENERATOR ENVIRONMENTAL TEST  

Microsoft Academic Search

The effects of simulated space vehicle vibration, acceleration and shock ;\\u000a on the operation and efficiency of a SNAP-III thermoelectric generator are ;\\u000a described. The test specifications were developed by Jet Propulsion Laboratories ;\\u000a for the third stage and payload of the Vega Vehicle. (auth)

1959-01-01

13

Design and optimization of compatible, segmented thermoelectric generators  

NASA Technical Reports Server (NTRS)

The thermoelectric compatiblity factor is used to rationally select materials for a segmented thermoelectric generator. the thermoelectric potential is used for the exact analytic expressions for materials with temperature dependent thermoelectric properties.

Snyder, G. Jeffrey

2003-01-01

14

Development of a New Generation of High-Temperature Thermoelectric Unicouples for Space Applications  

NASA Technical Reports Server (NTRS)

RTG's have enabled surface and deep space missions since 1961: a) 26 flight missions without any RTG failures; and b) Mission durations in excess of 25 years. Future NASA missions require RTG s with high specific power and high efficiency, while retaining long life (> 14 years) and high reliability, (i.e. 6-8 W/kg, 10-15% efficiency). JPL in partnership with NASA-GRC, NASA-MSFC, DOE, Universities and Industry is developing advanced thermoelectric materials and converters to meet future NASA needs.

Caillat, Thierry; Gogna, P.; Sakamoto, J.; Jewell, A.; Cheng, J.; Blair, R.; Fleurial, J. -P.; Ewell, R.

2006-01-01

15

Lead telluride as a thermoelectric material for thermoelectric power generation  

NASA Astrophysics Data System (ADS)

The specialized applications of thermoelectric generators are very successful and have motivated a search for materials with an improved figure of merit Z, and also for materials which operate at elevated temperatures. Lead telluride, PbTe, is an intermediate thermoelectric power generator. Its maximum operating temperature is 900 K. PbTe has a high melting point, good chemical stability, low vapor pressure and good chemical strength in addition to high figure of merit Z. Recently, research in thermoelectricity aims to obtain new improved materials for autonomous sources of electrical power in specialized medical, terrestial and space applications and to obtain an unconventional energy source after the oil crises of 1974. Although the efficiency of thermoelectric generators is rather low, typically ?5%, the other advantages, such as compactness, silent, reliability, long life, and long period of operation without attention, led to a wide range of applications. PbTe thermoelectric generators have been widely used by the US army, in space crafts to provide onboard power, and in pacemakers batteries. The general physical properties of lead telluride and factors affecting the figure of merit have been reviewed. Various possibilities of improving the figure of merit of the material have been given, including effect of grain size on reducing the lattice thermal conductivity ?L. Comparison of some transport properties of lead telluride with other thermoelectric materials and procedures of preparing compacts with transport properties very close to the single crystal values from PbTe powder by cold and hot-pressing techniques are discussed.

Dughaish, Z. H.

2002-09-01

16

Design optimization of thermoelectric devices for solar power generation  

Microsoft Academic Search

We present an improved theoretical model of a thermoelectric device which has been developed for geometrical optimization of the thermoelectric element legs and prediction of the performance of an optimum device in power generation mode. In contrast to the currently available methods, this model takes into account the effect of all the parameters contributing to the heat transfer process associated

S. A. Omer; D. G. Infield

1998-01-01

17

Improvements to solar thermoelectric generators through device design  

E-print Network

A solar thermoelectric generator (STEG) is a device which converts sunlight into electricity through the thermoelectric effect. A STEG is nominally formed when a thermoelectric generator (TEG), a type of solid state heat ...

Weinstein, Lee A. (Lee Adragon)

2013-01-01

18

Development of a radioisotope heat source for the two-watt radioisotope thermoelectric generator  

NASA Astrophysics Data System (ADS)

Described is a radioisotope heat source for the Two-Watt Radioisotope Thermoelectric Generator (RTG) which is being considered for possible application by the U.S. Navy and for other Department of Defense applications. The heat source thermal energy (75 Wt) is produced from the alpha decay of plutonium-238 which is in the form of high-fired plutonium dioxide. The capsule is non-vented and consists of three domed cylindrical components each closed with a corresponding sealed end cap. Surrounding the fuel is the liner component, which is fabricated from a tantalum-based alloy, T-111. Also fabricated from T-111 is the next component, the strength member, which serves to meet pressure and impact criteria. The outermost component, or clad, is the oxidation- and corrosion-resistant nickel-based alloy, Hastelloy S. This paper defines the design considerations, details the hardware fabrication and welding processes, discusses the addition of yttrium to the fuel to reduce liner embrittlement, and describes the testing that has been conducted or is planned to assure that there is fuel containment not only during the heat source operational life, but also in case of an accident environment.

Howell, Edwin I.; McNeil, Dennis C.; Amos, Wayne R.

1992-01-01

19

Solar thermoelectrics for small scale power generation  

E-print Network

In the past two decades, there has been a surge in the research of new thermoelectric (TE) materials, driven party by the need for clean and sustainable power generation technology. Utilizing the Seebeck effect, the ...

Amatya, Reja

2012-01-01

20

Modeling of concentrating solar thermoelectric generators  

E-print Network

The conversion of solar power into electricity is dominated by non-concentrating photovoltaics and concentrating solar thermal systems. Recently, it has been shown that solar thermoelectric generators (STEGs) are a viable ...

Ren, Zhifeng

21

Theoretical efficiency of solar thermoelectric energy generators  

E-print Network

This paper investigates the theoretical efficiency of solar thermoelectric generators (STEGs). A model is established including thermal concentration in addition to optical concentration. Based on the model, the maximum ...

Chen, Gang

22

Development and Demonstration of a Modeling Framework for Assessing the Efficacy of Using Mine Water for Thermoelectric Power Generation  

SciTech Connect

Thermoelectric power plants use large volumes of water for condenser cooling and other plant operations. Traditionally, this water has been withdrawn from the cleanest water available in streams and rivers. However, as demand for electrical power increases it places increasing demands on freshwater resources resulting in conflicts with other off stream water users. In July 2002, NETL and the Governor of Pennsylvania called for the use of water from abandoned mines to replace our reliance on the diminishing and sometimes over allocated surface water resource. In previous studies the National Mine Land Reclamation Center (NMLRC) at West Virginia University has demonstrated that mine water has the potential to reduce the capital cost of acquiring cooling water while at the same time improving the efficiency of the cooling process due to the constant water temperatures associated with deep mine discharges. The objectives of this project were to develop and demonstrate a user-friendly computer based design aid for assessing the costs, technical and regulatory aspects and potential environmental benefits for using mine water for thermoelectric generation. The framework provides a systematic process for evaluating the hydrologic, chemical, engineering and environmental factors to be considered in using mine water as an alternative to traditional freshwater supply. A field investigation and case study was conducted for the proposed 300 MW Beech Hollow Power Plant located in Champion, Pennsylvania. The field study based on previous research conducted by NMLRC identified mine water sources sufficient to reliably supply the 2-3,000gpm water supply requirement of Beech Hollow. A water collection, transportation and treatment system was designed around this facility. Using this case study a computer based design aid applicable to large industrial water users was developed utilizing water collection and handling principals derived in the field investigation and during previous studies of mine water and power plant cooling. Visual basic software was used to create general information/evaluation modules for a range of power plant water needs that were tested/verified against the Beech Hollow project. The program allows for consideration of blending mine water as needed as well as considering potential thermal and environmental benefits that can be derived from using constant temperature mine water. Users input mine water flow, quality, distance to source, elevations to determine collection, transport and treatment system design criteria. The program also evaluates low flow volumes and sustainable yields for various sources. All modules have been integrated into a seamless user friendly computer design aid and user's manual for evaluating the capital and operating costs of mine water use. The framework will facilitate the use of mine water for thermoelectric generation, reduce demand on freshwater resources and result in environmental benefits from reduced emissions and abated mine discharges.

None

2010-03-01

23

Thermoelectric power generation for hybrid-electric vehicle auxiliary power  

NASA Astrophysics Data System (ADS)

The plug-in hybrid-electric vehicle (PHEV) concept allows for a moderate driving range in electric mode but uses an onboard range extender to capitalize on the high energy density of fuels using a combustion-based generator, typically using an internal combustion engine. An alternative being developed here is a combustion-based thermoelectric generator in order to develop systems technologies which capitalize on the high power density and inherent benefits of solid-state thermoelectric power generation. This thermoelectric power unit may find application in many military, industrial, and consumer applications including range extension for PHEVs. In this research, a baseline prototype was constructed using a novel multi-fuel atomizer with diesel fuel, a conventional thermoelectric heat exchange configuration, and a commercially available bismuth telluride module (maximum 225°C). This prototype successfully demonstrated the viability of diesel fuel for thermoelectric power generation, provided a baseline performance for evaluating future improvements, provided the mechanism to develop simulation and analysis tools and methods, and highlighted areas requiring development. The improvements in heat transfer efficiency using catalytic combustion were evaluated, the system was redesigned to operate at temperatures around 500 °C, and the performance of advanced high temperature thermoelectric modules was examined.

Headings, Leon M.; Washington, Gregory N.; Midlam-Mohler, Shawn; Heremans, Joseph P.

2009-03-01

24

Compatibility of segmented thermoelectric generators  

NASA Technical Reports Server (NTRS)

It is well known that power generation efficiency improves when materials with appropriate properties are combined either in a cascaded or segmented fashion across a temperature gradient. Past methods for determining materials used in segmentation weremainly concerned with materials that have the highest figure of merit in the temperature range. However, the example of SiGe segmented with Bi2Te3 and/or various skutterudites shows a marked decline in device efficiency even though SiGe has the highest figure of merit in the temperature range. The origin of the incompatibility of SiGe with other thermoelectric materials leads to a general definition of compatibility and intrinsic efficiency. The compatibility factor derived as = (Jl+zr - 1) a is a function of only intrinsic material properties and temperature, which is represented by a ratio of current to conduction heat. For maximum efficiency the compatibility factor should not change with temperature both within a single material, and in the segmented leg as a whole. This leads to a measure of compatibility not only between segments, but also within a segment. General temperature trends show that materials are more self compatible at higher temperatures, and segmentation is more difficult across a larger -T. The compatibility factor can be used as a quantitative guide for deciding whether a material is better suited for segmentation orcascading. Analysis of compatibility factors and intrinsic efficiency for optimal segmentation are discussed, with intent to predict optimal material properties, temperature interfaces, and/or currentheat ratios.

Snyder, J.; Ursell, T.

2002-01-01

25

Thermoelectric power generation in a thermoacoustic refrigerator  

Microsoft Academic Search

Commercially available solid-state thermoelectric devices may be used for their electrical power generation capabilities when coupled to a thermoacoustic refrigerator or heat pump. General performance characteristics as well as bulk thermal conductivity for a selection of thermoelectric elements was first found by using a two-plate apparatus to maintain a constant temperature difference across the element. Further studies of an element’s

W. V. Slaton; J. C. H. Zeegers

2006-01-01

26

Method of operating a thermoelectric generator  

SciTech Connect

A method for operating a thermoelectric generator supplying a variable-load component includes commanding the variable-load component to operate at a first output and determining a first load current and a first load voltage to the variable-load component while operating at the commanded first output. The method also includes commanding the variable-load component to operate at a second output and determining a second load current and a second load voltage to the variable-load component while operating at the commanded second output. The method includes calculating a maximum power output of the thermoelectric generator from the determined first load current and voltage and the determined second load current and voltage, and commanding the variable-load component to operate at a third output. The commanded third output is configured to draw the calculated maximum power output from the thermoelectric generator.

Reynolds, Michael G; Cowgill, Joshua D

2013-11-05

27

Microfabricated thermoelectric power-generation devices  

NASA Technical Reports Server (NTRS)

A device for generating power to run an electronic component. The device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with a high temperature region. During operation, heat flows from the high temperature region into the heat-conducting substrate, from which the heat flows into the electrical power generator. A thermoelectric material (e.g., a BiTe alloy-based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. A low temperature region is located on the side of the thermoelectric material opposite that of the high temperature region. The thermal gradient generates electrical power and drives an electrical component.

Fleurial, Jean-Pierre (Inventor); Ryan, Margaret A. (Inventor); Borshchevsky, Alex (Inventor); Phillips, Wayne (Inventor); Kolawa, Elizabeth A. (Inventor); Snyder, G. Jeffrey (Inventor); Caillat, Thierry (Inventor); Kascich, Thorsten (Inventor); Mueller, Peter (Inventor)

2004-01-01

28

Modeling of solar thermal selective surfaces and thermoelectric generators  

E-print Network

A thermoelectric generator is a solid-state device that converts a heat flux into electrical power via the Seebeck effect. When a thermoelectric generator is inserted between a solar-absorbing surface and a heat sink, a ...

McEnaney, Kenneth

2010-01-01

29

General-purpose heat source: Research and development program, radioisotope thermoelectric generator/thin fragment impact test  

SciTech Connect

The general-purpose heat source provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system. The results of this test indicated that impact by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the converter housing, failure of one fueled clad, and release of a small quantity of fuel.

Reimus, M.A.H.; Hinckley, J.E.

1996-11-01

30

Development of segmented thermoelectric multicouple converter technology  

NASA Technical Reports Server (NTRS)

The Jet Propulsion Laboratory (JPL), Pratt & Whitney Rocketdyne, and Teledyne Energy Systems, Inc., have teamed together under JPL leadership to develop the next generation of advanced thermoelectric space reactor power conversion systems. The program goals are to develop the technologies needed to achieve a space nuclear power system specific mass goal of less than 30 kg/kW at the 100 kW power level with a greater than 15 year lifetime.

Fleurial, Jean-Pierre; Johnson, Kenneth; Sakamoto, Jeff; Huang, Chen-Kuo; Snyder, Jeff; Mondt, Jack; Blair, Richard; Frye, Patrick; Stapfer, Gerhard; Caillat, Thierry; Determan, William; Heshmatpour, Ben; Brooks, Michael; Tuttle, Karen

2006-01-01

31

Compatibility of Segments of Thermoelectric Generators  

NASA Technical Reports Server (NTRS)

A method of calculating (usually for the purpose of maximizing) the power-conversion efficiency of a segmented thermoelectric generator is based on equations derived from the fundamental equations of thermoelectricity. Because it is directly traceable to first principles, the method provides physical explanations in addition to predictions of phenomena involved in segmentation. In comparison with the finite-element method used heretofore to predict (without being able to explain) the behavior of a segmented thermoelectric generator, this method is much simpler to implement in practice: in particular, the efficiency of a segmented thermoelectric generator can be estimated by evaluating equations using only hand-held calculator with this method. In addition, the method provides for determination of cascading ratios. The concept of cascading is illustrated in the figure and the definition of the cascading ratio is defined in the figure caption. An important aspect of the method is its approach to the issue of compatibility among segments, in combination with introduction of the concept of compatibility within a segment. Prior approaches involved the use of only averaged material properties. Two materials in direct contact could be examined for compatibility with each other, but there was no general framework for analysis of compatibility. The present method establishes such a framework. The mathematical derivation of the method begins with the definition of reduced efficiency of a thermoelectric generator as the ratio between (1) its thermal-to-electric power-conversion efficiency and (2) its Carnot efficiency (the maximum efficiency theoretically attainable, given its hot- and cold-side temperatures). The derivation involves calculation of the reduced efficiency of a model thermoelectric generator for which the hot-side temperature is only infinitesimally greater than the cold-side temperature. The derivation includes consideration of the ratio (u) between the electric current and heat-conduction power and leads to the concept of compatibility factor (s) for a given thermoelectric material, defined as the value of u that maximizes the reduced efficiency of the aforementioned model thermoelectric generator.

Snyder, G. Jeffrey; Ursell, Tristan

2009-01-01

32

Molybdenum oxide electrodes for thermoelectric generators  

DOEpatents

The invention is directed to a composite article suitable for use in thermoelectric generators. The article comprises a thin film comprising molybdenum oxide as an electrode deposited by physical deposition techniques onto solid electrolyte. The invention is also directed to the method of making same.

Schmatz, Duane J. (Dearborn Heights, MI)

1989-01-01

33

Thermoelectric unicouple used for power generation  

NASA Technical Reports Server (NTRS)

A high-efficiency thermoelectric unicouple is used for power generation. The unicouple is formed with a plurality of legs, each leg formed of a plurality of segments. The legs are formed in a way that equalizes certain aspects of the different segments. Different materials are also described.

Caillat, Thierry (Inventor); Zoltan, Andrew (Inventor); Zoltan, Leslie (Inventor); Snyder, Jeffrey (Inventor)

2004-01-01

34

Modular Isotopic Thermoelectric Generator (MITG) Design and Development, Part A-E. Original was presented at 1983 Intersociety Energy Conversion Engineering Conference (IECEC)  

SciTech Connect

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 a 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. The resultant design is highly modular, consisting of standard RTG slices, each producing 24 watts at the desired output voltage of 28 volt. Thus, the design could be adapted to various space missions over a wide range of power levels, with little or no redesign. Each RTG slice consists of a 250-watt heat source module, eight multicouple thermoelectric modules, and standard sections of insulator, housing, radiator fins, and electrical circuit. The design makes it possible to check each thermoelectric module for electrical performance, thermal contact, leaktightness, and performance stability, after the generator is fully assembled; and to replace any deficient modules without disassembling the generator or perturbing the others. The RTG end sections provide the spring-loaded supports required to hold the free-standing heat source stack together during launch vibration. Detailed analysis indicates that the present generation of RTGs, using the same heat source modules. There is a duplicate copy of this document. OSTI has a copy of this paper.

Schock, A.

1983-04-29

35

Thermoelectric Power Generation Allison Duh and Joel Dungan  

E-print Network

Thermoelectric Power Generation Allison Duh and Joel Dungan May 15, 2013 #12;Introduction A thermoelectric generator (TEG) is a device that converts heat energy directly into electrical energy. Thermoelectric systems capitalize on semiconductor charge carriers excited by a temperature difference to convert

Lavaei, Javad

36

Thermophotovoltaic and thermoelectric portable power generators  

NASA Astrophysics Data System (ADS)

The quest for developing clean, quiet, and portable high energy density, and ultra-compact power sources continues. Although batteries offer a well known solution, limits on the chemistry developed to date constrain the energy density to 0.2 kWh/kg, whereas many hydrocarbon fuels have energy densities closer to 13 kWh/kg. The fundamental challenge remains: how efficiently and robustly can these widely available chemical fuels be converted into electricity in a millimeter to centimeter scale systems? Here we explore two promising technologies for high energy density power generators: thermophotovoltaics (TPV) and thermoelectrics (TE). These heat to electricity conversion processes are appealing because they are fully static leading to quiet and robust operation, allow for multifuel operation due to the ease of generating heat, and offer high power densities. We will present some previous work done in the TPV and TE fields. In addition we will outline the common technological barriers facing both approaches, as well as outline the main differences. Performance for state of the art research generators will be compared as well as projections for future practically achievable systems. A viable TPV or TE power source for a ten watt for one week mission can be built from a <10% efficient device which is achievable with current state of the art technology such as photonic crystals or advanced TE materials.

Chan, Walker R.; Waits, Christopher M.; Joannopoulos, John D.; Celanovic, Ivan

2014-06-01

37

Multi-mission radioisotope thermoelectric generator (MMRTG) program overview  

Microsoft Academic Search

Future NASA missions require safe, reliable, long-lived power systems for surface exploration of planetary bodies such as Mars as well as exploration of the solar system in the vacuum of space beyond Earth orbit. To address this need, the Department of Energy and NASA have initiated the development of radioisotope power systems, including the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). In

Fred Ritz; C. E. Peterson

2004-01-01

38

Water impacts on thermoelectric power generation.  

E-print Network

??The energy-water nexus represents a complex system of correlated resources, with particular relevance to thermoelectric power plants. Since thermoelectric power plants typically depend on water… (more)

Stillwell, Ashlynn Suzanne

2013-01-01

39

Thermoelectric materials development. Final report  

SciTech Connect

A systematic search for advanced thermoelectric materials was initiated at JPL several years ago to evaluate candidate materials which includes consideration of the following property attributes: (1) semiconducting properties; (2) large Seebeck coefficient; (3) high carrier mobility and high electrical conductivity; (4) low lattice thermal conductivity; and (5) chemical stability and low vapor pressure. Through this candidate screening process, JPL identified several families of materials as promising candidates for improved thermoelectric materials including the skutterudite family. There are several programs supporting various phases of the effort on these materials. As part of an ongoing effort to develop skutterudite materials with lower thermal conductivity values, several solid solutions and filled skutterudite materials were investigated under the effort sponsored by DOE. The efforts have primarily focused on: (1) study of existence and properties of solid solutions between the binary compounds CoSb{sub 3} and IrSb{sub 3}, and RuSb{sub 2}Te, and (2) CeFe{sub 4{minus}x}Sb{sub 12} based filled compositions. For the solid solutions, the lattice thermal conductivity reduction was expected to be reduced by the introduction of the Te and Ru atoms while in the case of CeFe{sub 4{minus}x}Ru{sub x}Sb{sub 12} based filled compositions. For the solid solutions, the lattice thermal conductivity reduction was expected to be reduced by the introduction of the Te and Ru atoms while in the case of CeFe{sub 4{minus}x}Ru{sub x}Sb{sub 12} filled compositions, the reduction would be caused by the rattling of Ce atoms located in the empty voids of the skutterudite structure and the substitution of Fe for Ru. The details of the sample preparation and characterization of their thermoelectric properties are reported in this report.

Fleurial, J.P.; Caillat, T.; Borshchevsky, A.

1998-09-01

40

Thermoelectric Generation Using Waste Heat in Steel Works  

NASA Astrophysics Data System (ADS)

The steelmaking industry in Japan has significantly reduced its energy use for the past several decades and has kept the highest energy efficiency in the world. However, the steelmaking industry is strongly required to develop new technologies for further energy conservation in view of energy security, high and volatile energy prices, and climate change. One of the key technologies to achieve the requirement is waste heat recovery. This paper describes the thermoelectric generation (TEG) system using the waste heat in the steelmaking process. In this system, the TEG unit, which consists of 16 thermoelectric modules made of Bi-Te thermoelectric materials, generates the electrical power directly by converting the radiant heat released from hot steel products. Each thermoelectric module, whose size is 50 mm × 50 mm × 4.2 mm, generates 18 W when the hot-side temperature is 523 K and the cold-side is 303 K. Therefore, the output of the TEG unit is over 250 W. The performance and the durability of the system have been investigated under various operating conditions in steel works. The results of the verification tests in the JFE steel Corporation's continuous casting line will be discussed.

Kuroki, Takashi; Kabeya, Kazuhisa; Makino, Kazuya; Kajihara, Takeshi; Kaibe, Hiromasa; Hachiuma, Hirokuni; Matsuno, Hidetoshi; Fujibayashi, Akio

2014-06-01

41

Test and evaluation of the Navy half-watt RTG. [Radioisotope Thermoelectric Generator  

NASA Technical Reports Server (NTRS)

The radioisotope thermoelectric generator (RTG) considered is to provide a continuous minimum power output of 0.5 watt at 6.0 to 8.5 volts for a minimum period of 15 years. The mechanical-electrical evaluation phase discussed involved the conduction of shock and vibration tests. The thermochemical-physical evaluation phase consisted of an analysis of the materials and the development of a thermal model. The thermoelectric evaluation phase included the accelerated testing of the thermoelectric modules.

Rosell, F. E., Jr.; Lane, S. D.; Eggers, P. E.; Gawthrop, W. E.; Rouklove, P. G.; Truscello, V. C.

1976-01-01

42

Self-Contained Thermoelectric Generator for Cell Phones  

NASA Astrophysics Data System (ADS)

Results of research and development of a 1 W thermoelectric generator for cell phones are presented. A physical model of the generator with catalytic combustion of gas fuel is proposed. A computer simulation method is used to determine the optimal parameters of the thermopile, catalytic heat source, and microgenerator heat rejection system whereby the efficiency of gas combustion heat conversion into electrical energy is a factor of two higher compared with existing analogs. The generator design is described, and results of experimental research on its parameters and the charging rate of cell phone batteries with capacity of 900 mA h to 1600 mA h are given. In the self-contained operating mode of various low-power devices, the elaborated thermoelectric generator with a catalytic heat source is an alternative to traditional sources of chemical energy.

Anatychuk, L. I.; Mykhailovsky, V. Ya.; Strutynska, L. T.

2011-05-01

43

Thermoelectric power generation systems recovering heat from combustible solid waste in Japan  

Microsoft Academic Search

The status and future prospects on the development of thermoelectric power generation systems utilizing heat from the municipal solid waste in Japan are reviewed in this paper. Two ongoing research and development programs related to this application in Japan are briefly introduced. The characteristics of heat from the solid waste processing system lead to the peculiar concept of thermoelectric power

Takenobu Kajikawa

1996-01-01

44

Thermoelectric material development. Final report  

SciTech Connect

A search was made for improved TE materials that could have higher efficiency than state-of-the-art SiGe alloys used in Radioisotope Thermoelectric Generators. A new family of materials having the skutterudite structure was identified (cubic space group Im3, formula (Fe, Co, Ni)As{sub 3}). Properties of n-type IrSb{sub 3}, CoSb{sub 3}, and their solid solutions were investigated. Pt, Te, Tl, and In were used as dopants. The thermal conductivity was reduced by about 70% for the solid solutions vs the binary compounds. A maximum ZT of about 0.36 was measured on Co-rich solid solutions which is 160% improved over that of the binary compounds.

Vandersande, J.W.; Allevato, C.; Caillat, T.

1994-10-01

45

Fabrication of Advanced Thermoelectric Materials by Hierarchical Nanovoid Generation  

NASA Technical Reports Server (NTRS)

A novel method to prepare an advanced thermoelectric material has hierarchical structures embedded with nanometer-sized voids which are key to enhancement of the thermoelectric performance. Solution-based thin film deposition technique enables preparation of stable film of thermoelectric material and void generator (voigen). A subsequent thermal process creates hierarchical nanovoid structure inside the thermoelectric material. Potential application areas of this advanced thermoelectric material with nanovoid structure are commercial applications (electronics cooling), medical and scientific applications (biological analysis device, medical imaging systems), telecommunications, and defense and military applications (night vision equipments).

Choi, Sang Hyouk (Inventor); Park, Yeonjoon (Inventor); Chu, Sang-Hyon (Inventor); Elliott, James R. (Inventor); King, Glen C. (Inventor); Kim, Jae-Woo (Inventor); Lillehei, Peter T. (Inventor); Stoakley, Diane M. (Inventor)

2011-01-01

46

Modeling of concentrating solar thermoelectric generators  

NASA Astrophysics Data System (ADS)

The conversion of solar power into electricity is dominated by non-concentrating photovoltaics and concentrating solar thermal systems. Recently, it has been shown that solar thermoelectric generators (STEGs) are a viable alternative in the non-concentrating regime. This paper addresses the possibility of STEGs being used as the power block in concentrating solar power systems. STEG power blocks have no moving parts, they are scalable, and they eliminate the need for an external traditional thermomechanical generator, such as a steam turbine or Stirling engine. Using existing skutterudite and bismuth telluride materials, concentrating STEGs can have efficiencies exceeding 10% based on a geometric optical concentration ratio of 45.

McEnaney, Kenneth; Kraemer, Daniel; Ren, Zhifeng; Chen, Gang

2011-10-01

47

CFD modeling of thermoelectric generators in automotive EGR-coolers  

NASA Astrophysics Data System (ADS)

A large amount of the waste heat in the exhaust gases from diesel engines is removed in the exhaust gas recirculation (EGR) cooler. Introducing a thermoelectric generator (TEG) in an EGR cooler requires a completely new design of the heat exchanger. To accomplish that a model of the TEG-EGR system is required. In this work, a transient 3D CFD model for simulation of gas flow, heat transfer and power generation has been developed. This model allows critical design parameters in the TEG-EGR to be identified and design requirements for the systems to be specified. Besides the prediction of Seebeck, Peltier, Thomson and Joule effects, the simulations also give detailed insight to the temperature gradients in the gas-phase and inside the thermoelectric (TE) elements. The model is a very valuable tool to identify bottlenecks, improve design, select optimal TE materials and operating conditions. The results show that the greatest heat transfer resistance is located in the gas phase and it is critical to reduce this in order to achieve a large temperature difference over the thermoelectric elements without compromising on the maximum allowable pressure drop in the system. Further results from an investigation of the thermoelectric performance during a vehicle test cycle is presented.

Högblom, Olle; Andersson, Ronnie

2012-06-01

48

Analysis of waste-heat thermoelectric power generators  

Microsoft Academic Search

A real thermoelectric power generator utilizing waste heat is proposed. The generator is treated as an external and internal irreversible heat engine. The specific power output of the generator is analyzed and compared with that of the Carnot, endoreversible and external reversible thermoelectric heat engines.

Chih Wu

1996-01-01

49

Prototype Combined Heater/Thermoelectric Power Generator for Remote Applications  

NASA Astrophysics Data System (ADS)

This study presents a prototype thermoelectric generator (TEG) developed for remote applications in villages that are not connected to the electrical power grid. For ecological and economic reasons, there is growing interest in harvesting waste heat from biomass stoves to produce some electricity. Because regular maintenance is not required, TEGs are an attractive choice for small-scale power generation in inaccessible areas. The prototype developed in our laboratory is especially designed to be implemented in stoves that are also used for domestic hot water heating. The aim of this system is to provide a few watts to householders, so they have the ability to charge cellular phones and radios, and to get some light at night. A complete prototype TEG using commercial (bismuth telluride) thermoelectric modules has been built, including system integration with an electric DC/DC converter. The DC/DC converter has a maximum power point tracker (MPPT) driven by an MC9SO8 microcontroller, which optimizes the electrical energy stored in a valve-regulated lead-acid battery. Physical models were used to study the behavior of the thermoelectric system and to optimize the performance of the MPPT. Experiments using a hot gas generator to simulate the exhaust of the combustion chamber of a stove are used to evaluate the system. Additionally, potential uses of such generators are presented.

Champier, D.; Favarel, C.; Bédécarrats, J. P.; Kousksou, T.; Rozis, J. F.

2013-07-01

50

Autonomous Underwater Vehicle Thermoelectric Power Generation  

NASA Astrophysics Data System (ADS)

Autonomous underwater vehicles (AUVs) are a vital part of the oceanographer's toolbox, allowing long-term measurements across a range of ocean depths of a number of ocean properties such as salinity, fluorescence, and temperature profile. Buoyancy-based gliding, rather than direct propulsion, dramatically reduces AUV power consumption and allows long-duration missions on the order of months rather than hours or days, allowing large distances to be analyzed or many successive analyses of a certain area without the need for retrieval. Recent versions of these gliders have seen the buoyancy variation system change from electrically powered to thermally powered using phase-change materials, however a significant battery pack is still required to power communications and sensors, with power consumption in the region of 250 mW. The authors propose a novel application of a thermoelectric generation system, utilizing the depth-related variation in oceanic temperature. A thermal energy store provides a temperature differential across which a thermoelectric device can generate from repeated dives, with the primary purpose of extending mission range. The system is modeled in Simulink to analyze the effect of variation in design parameters. The system proves capable of generating all required power for a modern AUV.

Buckle, J. R.; Knox, A.; Siviter, J.; Montecucco, A.

2013-07-01

51

Microscreen radiation shield for thermoelectric generator  

DOEpatents

The present invention provides a microscreen radiation shield which reduces radiative heat losses in thermoelectric generators such as sodium heat engines without reducing the efficiency of operation of such devices. The radiation shield is adapted to be interposed between a reaction zone and a means for condensing an alkali metal vapor in a thermoelectric generator for converting heat energy directly to electrical energy. The radiation shield acts to reflect infrared radiation emanating from the reaction zone back toward the reaction zone while permitting the passage of the alkali metal vapor to the condensing means. The radiation shield includes a woven wire mesh screen or a metal foil having a plurality of orifices formed therein. The orifices in the foil and the spacing between the wires in the mesh is such that radiant heat is reflected back toward the reaction zone in the interior of the generator, while the much smaller diameter alkali metal atoms such as sodium pass directly through the orifices or along the metal surfaces of the shield and through the orifices with little or no impedance.

Hunt, Thomas K. (Ann Arbor, MI); Novak, Robert F. (Farmington Hills, MI); McBride, James R. (Ypsilanti, MI)

1990-01-01

52

Thermoelectric Analysis for Helical Power Generation Systems  

NASA Astrophysics Data System (ADS)

The performance of a three-dimensional helical thermoelectric generation (TEG) system is examined by exposing it to a temperature difference with hot and cold sources. The helical paths for the two thermal fluids give the TEG device the potential to efficiently convert thermal energy. The characteristic performance of the helical system is numerically analyzed by using the finite-volume method in a compact system. The helical system is compared with a straight system in which all the thermoelectric (TE) elements present equivalent geometry. The difference in the TE performance between the two systems is not significant when the TE surfaces are maintained at constant temperatures. Both the electromotive force and the current in the TEG system increase linearly with the temperature difference ? T applied at the two module surfaces. The current preferentially flows through a main path determined by the geometry of the TE element. The merits of the helical design are its compactness, space saving, and smooth fluid flow due to gravity, compared with the straight system.

Meng, Xiangning; Fujisaka, Takeyuki; Suzuki, Ryosuke O.

2014-06-01

53

Thermoelectric module construction for low temperature gradient power generation  

Microsoft Academic Search

Energy related carbon dioxide emissions are the largest contributors to greenhouse gasses [1]. Thermoelectric power generation that exploits natural temperature differences between the air and earth can be a zero-emission replacement to small stand-alone power sources. Maximizing the temperature drop across the module is crucial to achieving optimal output power. An equation relating output power to thermoelectric module parameters is

Y. Meydbray; R. Singh; Ali Shakouri

2005-01-01

54

Fiber optic signal amplifier using thermoelectric power generation  

DOEpatents

A remote fiber optic signal amplifier for use as a repeater/amplifier, such as in transoceanic communications, powered by a Pu.sub.238 or Sr.sub.90 thermoelectric generator. The amplifier comprises a unit with connections on the receiving and sending sides of the communications system, and an erbium-doped fiber amplifier connecting each sending fiber to each receiving fiber. The thermoelectric generator, preferably a Pu.sub.238 or Sr.sub.90 thermoelectric generator delivers power to the amplifiers through a regulator. The heat exchange surfaces of the thermoelectric generator are made of materials resistant to corrosion and biological growth and are directly exposed to the outside, such as the ocean water in transoceanic communications.

Hart, Mark M. (Aiken, SC)

1995-01-01

55

A power conditioning system for radioisotope thermoelectric generator energy sources  

NASA Technical Reports Server (NTRS)

The use of radioisotope thermoelectric generators (RTG) as the primary source of energy in unmanned spacecraft is discussed. RTG output control, power conditioning system requirements, the electrical design, and circuit performance are also discussed.

Gillis, J. A., Jr.

1974-01-01

56

Fiber optic signal amplifier using thermoelectric power generation  

DOEpatents

A remote fiber optic signal amplifier for use as a repeater/amplifier, such as in transoceanic communication, powered by a Pu{sub 238} or Sr{sub 90} thermoelectric generator. The amplifier comprises a unit with connections on the receiving and sending sides of the communications system, and an erbium-doped fiber amplifier connecting each sending fiber to each receiving fiber. The thermoelectric generator, preferably a Pu{sub 238} or Sr{sub 90} thermoelectric generator delivers power to the amplifiers through a regulator. The heat exchange surfaces of the thermoelectric generator are made of material resistant to corrosion and biological growth and are directly exposed to the outside, such as the ocean water in transoceanic communications.

Hart, M.M.

1993-01-01

57

Fiber optic signal amplifier using thermoelectric power generation  

DOEpatents

A remote fiber optic signal amplifier for use as a repeater/amplifier, such as in transoceanic communications, powered by a Pu{sub 238} or Sr{sub 90} thermoelectric generator. The amplifier comprises a unit with connections on the receiving and sending sides of the communications system, and an erbium-doped fiber amplifier connecting each sending fiber to each receiving fiber. The thermoelectric generator, preferably a Pu{sub 238} or Sr{sub 90} thermoelectric generator delivers power to the amplifiers through a regulator. The heat exchange surfaces of the thermoelectric generator are made of materials resistant to corrosion and biological growth and are directly exposed to the outside, such as the ocean water in transoceanic communications. 2 figs.

Hart, M.M.

1995-04-18

58

High-density thermoelectric power generation and nanoscale thermal metrology  

E-print Network

Thermoelectric power generation has been around for over 50 years but has seen very little large scale implementation due to the inherently low efficiencies and powers available from known materials. Recent material advances ...

Mayer, Peter (Peter Matthew), 1978-

2007-01-01

59

Modeling of thin-film solar thermoelectric generators  

E-print Network

Recent advances in solar thermoelectric generator (STEG) performance have raised their prospect as a potential technology to convert solar energy into electricity. This paper presents an analysis of thin-film STEGs. ...

Weinstein, Lee Adragon

60

Thermoelectric generator and method for the fabrication thereof  

DOEpatents

A thermoelectric generator using semiconductor elements for responding to a temperature gradient to produce electrical energy with all of the semiconductor elements being of the same type is disclosed. A continuous process for forming substrates on which the semiconductor elements and superstrates are deposited and a process for forming the semiconductor elements on the substrates are also disclosed. The substrates with the semiconductor elements thereon are combined with superstrates to form modules for use as thermoelectric generators.

Benson, D.K.; Tracy, C.E.

1984-08-01

61

Thermoelectric generator and method for the fabrication thereof  

DOEpatents

A thermoelectric generator using semiconductor elements for responding to a temperature gradient to produce electrical energy with all of the semiconductor elements being of the same type is disclosed. A continuous process for forming substrates on which the semiconductor elements and superstrates are deposited and a process for forming the semiconductor elements on the substrates are also disclosed. The substrates with the semiconductor elements thereon are combined with superstrates to form modules for use thermoelectric generators.

Benson, David K. (Golden, CO); Tracy, C. Edwin (Golden, CO)

1987-01-01

62

An overview of the Radioisotope Thermoelectric Generator Transporation System Program  

SciTech Connect

Radioisotope Thermoelectric Generators (RTG) convert the heat generated by radioactive decay to electricity using thermocouples. RTGs have a long operating life, are reasonably lightweight, and require little or no maintenance once assembled and tested. These factors make RTGs particularly attractive for use in spacecraft However, because RTGs contain significant quantities of radioactive materials, normally plutonium-238 and its decay products, they must be transported in packages built in accordance with Title 10, Code of Federal Regulations, Part 71. The US Department of Energy assigned the Radioisotope Thermoelectric Generator Transportation System (RTGTS) Program to Westinghouse Hanford Company in 1988 to develop a system meeting the regulatory requirements. The program objective was to develop a transportation system that would fully comply with 10 CFR 71 while protecting RTGs from adverse environmental conditions during normal conditions of transport (e.g., shock and heat). The RTGTS is scheduled for completion in December 1996 and will be available to support the National Aeronautics and Space Administrations Cassini mission to Saturn in October 1997. This paper provides an overview of the RTGTS and discusses the hardware being produced. Additionally, various program management innovations mandated by recent ma or changes in the US Department of Energy structure and resources will be outlined.

McCoy, J.C.

1995-10-01

63

Estimation of Thermoelectric Generator Performance by Finite Element Modeling  

NASA Astrophysics Data System (ADS)

Prediction of thermoelectric performance parameters by numerical methods is an inherent part of thermoelectric generator (TEG) development and allows for time- and cost-saving assessment of material combinations and variations of crucial design parameters (e.g., shape, pellet length, and thermal coupling). Considering the complexity of a TEG system and its numerous affecting factors, the clarity and the flexibility of a mathematical treatment comes to the fore. Comfortable tools are provided by commercial finite element modeling (FEM) software offering powerful geometry interfaces, mesh generators, solvers, and postprocessing options. We describe the level of development and the simulation results of a three dimensional (3D) TEG FEM. Using ANSYS 11.0, we implemented and simulated a TEG module geometry under various conditions. Comparative analytical one dimensional (1D) results and a direct comparison with inhouse-developed TEG simulation software show the consistency of results. Several pellet aspect ratios and contact property configurations (thermal/electrical interface resistance) were evaluated for their impact on the TEG performance as well as parasitic effects such as convection, radiation, and conductive heat bypass. The scenarios considered revealed the highest efficiency decay for convectionally loaded setups (up to 4.8%pts), followed by the impacts of contact resistances (up to 4.8%pts), by radiation (up to 0.56%pts), and by thermal conduction of a solid filling material within the voids of the module construction (up to 0.14%pts).

Ziolkowski, P.; Poinas, P.; Leszczynski, J.; Karpinski, G.; Müller, E.

2010-09-01

64

Tests and evaluation of multihundred watt thermoelectric generators at JPL  

NASA Technical Reports Server (NTRS)

The multihundred watt (MHW) thermoelectric generator, based on silicon-germanium thermoelectric technology, delivers a nominal power output of 150 watts with an efficiency of about 6%. The two Voyager space probes each use three such generators assembled in tandem on a boom. A total of seven MHW type thermoelectric generators were tested at JPL in support of the Voyager project. The tests consisted of: (1) parametric evaluation of the electrical characteristics of the devices over a wide range of output voltage for different values of input power, different operating ambients (air, vacuum), and different internal environments (argon, helium, xenon, mixture of these gases, and vacuum) at different pressures to allow evaluation of the influences of both gas and pressure on the performance of the generator; (2) tests to determine the transient behavior of the generators; and (3) operation of the generator in conjunction with the Voyager spacecraft.

Rouklove, P.

1977-01-01

65

RTGs - The powering of Ulysses. [Radio-isotope Thermoelectric Generator  

NASA Technical Reports Server (NTRS)

The radio-isotope thermoelectric generator (RTG) for Ulysses' electronic supply is described noting that lack of sufficient sunlight renders usual solar cell power generation ineffective due to increased distance from sun. The history of the RTG in the U.S.A. is reviewed citing the first RTG launch in 1961 with an electrical output of 2.7 W and the improved Ulysses RTG, which provides 285 W at mission beginning and 250 W at mission end. The RTG concept is discussed including the most recent RTG technology developed by the DOE, the General Purpose Heat Source RTG (GPHS-RTG). The system relies upon heat generated by radioactive decay using radioactive plutonium-238, which is converted directly to energy using the Seebeck method.

Mastal, E. F.; Campbell, R. W.

1990-01-01

66

High-Temperature High-Efficiency Solar Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

Inspired by recent high-efficiency thermoelectric modules, we consider thermoelectrics for terrestrial applications in concentrated solar thermoelectric generators (STEGs). The STEG is modeled as two subsystems: a TEG, and a solar absorber that efficiently captures the concentrated sunlight and limits radiative losses from the system. The TEG subsystem is modeled using thermoelectric compatibility theory; this model does not constrain the material properties to be constant with temperature. Considering a three-stage TEG based on current record modules, this model suggests that 18% efficiency could be experimentally expected with a temperature gradient of 1000°C to 100°C. Achieving 15% overall STEG efficiency thus requires an absorber efficiency above 85%, and we consider two methods to achieve this: solar-selective absorbers and thermally insulating cavities. When the TEG and absorber subsystem models are combined, we expect that the STEG modeled here could achieve 15% efficiency with optical concentration between 250 and 300 suns.

Baranowski, Lauryn L.; Warren, Emily L.; Toberer, Eric S.

2014-06-01

67

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

NASA Astrophysics Data System (ADS)

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.

Jovanovic, Velimir; Ghamaty, Saeid

2006-03-01

68

Interferometric Analysis of Thermomechanical Deformations in Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

In thermoelectric applications, optimized thermal contacts are essential to enable efficient and homogeneous flow of heat currents. Thermomechanical stresses may lead to surface deformation, which alters the thermal contact. As a result, the heat current density is reduced and no longer homogeneous. Also an undesired temperature gradient perpendicular to the heat flow develops, and hence this temperature gradient again causes thermomechanical stresses. The described thermomechanical problems are particularly important in applications where high operating temperatures and hence large temperature differences are used. Also, system durability is a crucial aspect, especially in applications where thermal cycles occur (i.e., in the field of waste heat regeneration of car combustion engines). We describe a measuring technique to detect and evaluate the influence of these deformations. To analyze the surface and external points of contact of a thermoelectric generator (TEG), a measurement setup based on speckle interferometry is used. Temperature gradients as well as small surface deflections in the ?m range have to be measured simultaneously. Therefore, an optical as well as a thermography camera are used to create a holistic image of the deformation and to analyze the influence of this deformation on the TEG structure.

Morschel, Marlis; Bastian, Georg

2013-07-01

69

A Thermoelectric Generation System and Its Power Electronics Stage  

NASA Astrophysics Data System (ADS)

The electricity produced by a thermoelectric generator (TEG) must satisfy the requirements of specific loads given the signal level, stability, and power performance. In the design of such systems, one major challenge involves the interactions between the thermoelectric power source and the power stage and signal-conditioning circuits of the load, including DC-DC conversion, the maximum power point tracking (MPPT) controller, and other power management controllers. In this paper, a survey of existing power electronics designs for TEG systems is presented first. Second, a flat, wall-like TEG system consisting of 32 modules is experimentally optimized, and the improved power parameters are tested. Power-conditioning circuitry based on an interleaved boost DC-DC converter is then developed for the TEG system in terms of the tested power specification. The power electronics design features a combined control scheme with an MPPT and a constant output voltage as well as the low-voltage and high-current output characteristics of the TEG system. The experimental results of the TEG system with the power electronics stage and with purely resistive loads are compared. The comparisons verify the feasibility and effectiveness of the proposed design. Finally, the thermal-electric coupling effects caused by current-related heat source terms, such as the Peltier effect etc., are reported and discussed, and the potential influence on the power electronics design due to such coupling is analyzed.

Gao, Junling; Sun, Kai; Ni, Longxian; Chen, Min; Kang, Zhengdong; Zhang, Li; Xing, Yan; Zhang, Jianzhong

2012-06-01

70

A COMBUSTION-BASED MEMS THERMOELECTRIC POWER GENERATOR  

Microsoft Academic Search

SUMMARY A thermoelectric generator with integrated catalytic combustion has been microfabricated and successfully tested. The device consists of a high-temperature silicon-germanium thermopile supported on a thermally insulating silicon nitride membrane. Heat is supplied by catalytic combustion of fuels on the underside of the membrane. Power output has been generated from on- chip autothermal combustion of hydrogen, ammonia and butane, with

Samuel B. Schaevitz; Aleksander J. Franz; Klavs F. Jensen; Martin A. Schmidt

2001-01-01

71

Miniaturized thermoelectric generators based on poly-Si and poly-SiGe surface micromachining  

Microsoft Academic Search

We report on miniaturized thermoelectric generators (TEGs) which are being developed to convert waste heat into a few microwatts of electrical power, sufficient to supply microelectronic circuitry. A BiCMOS realization using standard materials is favored to make these generators amenable to low cost applications. In order to optimize our device, the design and the material properties have been studied. The

M. Strasser; R. Aigner; M. Franosch; G. Wachutka

2002-01-01

72

Thermoelectric generator fabricated via laser-induced forward transfer M.Feinaeugle1  

E-print Network

Thermoelectric generator fabricated via laser-induced forward transfer M.Feinaeugle1 , C.L. Sones1 of a thermoelectric generator with the rapid, lithography-less technique of laser-induced forward transfer (LIFT on one substrate. The design of the proposed thermoelectric generator was selected to demonstrate

73

Emitted radiation characteristics of plutonium dioxide radioisotope thermoelectric generators  

NASA Technical Reports Server (NTRS)

The nuclear and emitted radiation characteristics of the radioisotope elements and impurities in commercial grade plutonium dioxide are presented in detail. The development of the methods of analysis are presented. Radioisotope thermoelectric generators (RTG) of 1575, 3468 and 5679 thermal watts are characterized with respect to neutron and gamma photon source strength as well as spatial and number flux distribution. The results are presented as a function of detector position and light element contamination concentration for fuel age ranging from 'fresh' to 18 years. The data may be used to obtain results for given O-18 and Pu-236 concentrations. The neutron and gamma photon flux and dose calculations compare favorably with reported experimental values for SNAP-27.

Gingo, P. J.; Steyn, J. J.

1971-01-01

74

Small-Scale Pellet Boiler with Thermoelectric Generator  

Microsoft Academic Search

Pellet boilers need auxiliary electrical power to provide CO2 -balanced heat in a comfortable and environment-friendly way. The idea is to produce this and some extra electricity within the furnace in order to save resources and to gain operation reliability and independency. Thermoelectric generators (TEGs) allow direct conversion of heat to electrical power. They have the advantage of a long

Wilhelm Moser; Gunther Friedl; Walter Haslinger; Hermann Hofbauer

2006-01-01

75

Molybdenum-platinum-oxide electrodes for thermoelectric generators  

DOEpatents

The invention is directed to a composite article suitable for use in thermoelectric generators. The article comprises a solid electrolyte carrying a thin film comprising molybdenum-platinum-oxide as an electrode deposited by physical deposition techniques. The invention is also directed to the method of making same.

Schmatz, Duane J. (Dearborn Heights, MI)

1990-01-01

76

Micromachined CMOS thermoelectric generators as on-chip power supply  

Microsoft Academic Search

As the power consumption of a large number of microelectronic devices has been continuously reduced in recent years, power supply units of a few microwatts have become sufficient for their operation. Our improved micro-scale thermoelectric generator (?-TEG) is based on polysilicon surface micromachining and is designed to convert waste heat into electrical power. Since this device is compatible with standard

M. Strasser; R. Aigner; C. Lauterbach; T. F. Sturm; M. Franosch; G. Wachutka

2004-01-01

77

Advanced Subcritical Assistance Radioisotope Thermoelectric Generator: An Imperative Solution for the Future of NASA Exploration  

NASA Astrophysics Data System (ADS)

A new generation of radioisotope thermoelectrical generator is proposed for very long space exploration missions. The Advanced Subcritical Assistance Radioisotope Thermoelectric Generator (ASA-RTG) amplify the power from natural decay of pu-238 by a small subcritical multiplication produced from the small neutron background generated from (?, n) reactions between the ? particles from Pu-238 and beryllium, lithium or other low-Z isotope, extracting the maximum advantage and performance from the precious ? disintegration, and then of the very scarce pu-238. The process is self controlled by the natural decay of Pu-238 with the progressive reduction of the power output (RTG) and additionally and simultaneously compensate by the natural decay of a neutronic poisson which increase simultaneously the subcritical multiplication resulting in a contrary effect, i.e., causing an increase in the power. ASA-RTG is not in conflict with previous RTG, and could fit within the type of Radioisotope Thermoelectric Generator developed for NASA space missions as the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) and the Advanced Stirling Radioisotope Generator (ASRG).

Arias, F. J.

78

A prototype micro-thermoelectric power generator for micro-electromechanical systems  

NASA Astrophysics Data System (ADS)

A prototype micro-thermoelectric power generator (micro-TEG) system based on micro-combustion concept has been developed and presented here. The system consists of Bismuth-Telluride based thermoelectric modules mounted on a 0.5 cm3 volume microcombustor. The hot combustion gases from the microcombustor are allowed to flow in reverse direction through a heating cup to maximize the heat transfer from hot combustion products to thermoelectric modules. The system delivers a maximum power of 2.35 W with a fuel (propane) flow rate of 3.98 g/h. Maximum power is achieved at a voltage of 4.34 V, current 0.54 A with a maximum conversion efficiency of 4.58%. The system generates electric power with an improvement of over 83% in energy conversion efficiency over existing micro-TEG systems.

Yadav, Shambhoo; Sharma, Pooja; Yamasani, Prathima; Minaev, S.; Kumar, Sudarshan

2014-03-01

79

Experimental investigation on thermoelectric generator of micro hybrid power source  

NASA Astrophysics Data System (ADS)

The micro power system, which is composed of photovoltaic solar cell, heat conductor, thermoelectric generator (TEG) module and fin heat sink has been developed in our laboratory. A photovoltaic silicon solar cell of the P-N junction type is sensitive to radiant energy of wavelength from 5,000 Å to 12,000 Å. Radiation under and within this range is converted not only into electric energy but also into heat energy. The wavelength longer than this range is also converted into heat energy, which degrades the conversion efficiency of the solar cell. TEG produces electrical power from temperature difference via Seebeck effect that can be put under the solar cell to absorb the heat. The heat energy can be converted into electrical power. It was found that when TEG surface area was 150mm×60mm, it could generate 0.24V output voltage and 4.18mA short circuit at ambient temperature varying between 5-10°C at winter. It also could generate 1.3V output voltage and 16mA short circuit at ambient temperature varying between 30-36°C at summer. In fact we can use a dc-dc boost up converter to enlarge the output voltage to meet the requirements of wireless sensor network nodes or its recharging battery. It will be an alternative power source for many portable electronic types of equipment.

Shang, Yonghong; Li, Yanqiu; Yu, Hongyun; Sun, Hongguang; Su, Bo

2007-12-01

80

Development of Thermoelectric Devices for Structural Composites.  

E-print Network

??The study presented in this thesis covers a multiple methods for manufacturing thermoelectric structural composites for waste heat energy harvesting efficiently. Various attempts to fabricate… (more)

Nattiyatharil Panachaveettil, Oonnittan Jacob

2011-01-01

81

Evaluation of High Step-Up Power Electronics Stages in Thermoelectric Generator Systems  

NASA Astrophysics Data System (ADS)

To develop practical thermoelectric generator (TEG) systems, especially radioisotope thermoelectric power supplies for deep-space exploration, a power conditioning stage with high step-up gain is indispensable. This stage is used to step up the low output voltage of thermoelectric generators to the required high level. Furthermore, maximum power point tracking control for TEG modules needs to be implemented into the power electronics stages. In this paper, the temperature-dependent electrical characteristics of a thermoelectric generator are analyzed in depth. Three typical high step-up power converters suitable for TEG applications are discussed: an interleaved boost converter, a boost converter with a coupled inductor, and an interleaved boost converter with an auxiliary transformer. A general comparison of the three high step-up converters is conducted to study the step-up gain, conversion efficiency, and input current ripples. The interleaved boost converter with an auxiliary transformer is found to be the most suitable topology for TEG applications, which is verified by experiments.

Sun, Kai; Ni, Longxian; Chen, Min; Wu, Hongfei; Xing, Yan; Rosendahl, Lasse

2013-07-01

82

High-efficiency photovoltaic technology including thermoelectric generation  

NASA Astrophysics Data System (ADS)

Nowadays, photovoltaic solar energy is a clean and reliable source for producing electric power. Most photovoltaic systems have been designed and built up for use in applications with low power requirements. The efficiency of solar cells is quite low, obtaining best results in monocrystalline silicon structures, with an efficiency of about 18%. When temperature rises, photovoltaic cell efficiency decreases, given that the short-circuit current is slightly increased, and the open-circuit voltage, fill factor and power output are reduced. To ensure that this does not affect performance, this paper describes how to interconnect photovoltaic and thermoelectric technology into a single structure. The temperature gradient in the solar panel is used to supply thermoelectric cells, which generate electricity, achieving a positive contribution to the total balance of the complete system.

Fisac, Miguel; Villasevil, Francesc X.; López, Antonio M.

2014-04-01

83

Optimal working conditions for thermoelectric generators with realistic thermal coupling  

E-print Network

We study how maximum output power can be obtained from a thermoelectric generator(TEG) with nonideal heat exchangers. We demonstrate with an analytic approach based on a force-flux formalism that the sole improvement of the intrinsic characteristics of thermoelectric modules including the enhancement of the figure of merit is of limited interest: the constraints imposed by the working conditions of the TEG must be considered on the same footing. Introducing an effective thermal conductance we derive the conditions which permit maximization of both efficiency and power production of the TEG dissipatively coupled to heat reservoirs. Thermal impedance matching must be accounted for as well as electrical impedance matching in order to maximize the output power. Our calculations also show that the thermal impedance does not only depend on the thermal conductivity at zero electrical current: it also depends on the TEG figure of merit. Our analysis thus yields both electrical and thermal conditions permitting optima...

Apertet, Y; Glavatskaya, O; Goupil, C; Lecoeur, P

2011-01-01

84

Temporal Evolution of Water Use for Thermoelectric Generation  

NASA Astrophysics Data System (ADS)

The long lifespan of power plants (30 - 50 yr) results in the current power plant fleet representing a legacy of past variations in fuel availability and costs, water availability and water rights, and advances in technologies, such as combined cycle plants, which impact trends in water consumption. The objective of this study was to reconstruct past water consumption and withdrawal of thermoelectric generation based on data on controls, including fuel types, generator technologies, and cooling systems, using Texas as a case study and comparing with the US. Fuel sources in Texas varied over time, from predominantly natural gas in the 1960s and early 1970s to coal and nuclear sources following the 1973 oil embargo and more recently to large increases in natural gas generation (85% increase 1998 - 2004) in response to hydraulic fracturing and low natural gas prices. The dominant generator technology in Texas was steam turbines until the early 1990s; however, combined cycle plants markedly increased in the late 1990s (400% increase 1998 - 2004). Proliferation of cooling ponds in Texas, mostly in the 1970s and 1980s (340% increase) reflects availability of large quantities of unappropriated surface water and increases in water rights permitting during this time and lower cost and higher cooling efficiency of ponds relative to wet cooling towers. Water consumption for thermoelectricity in Texas in 2010 totaled ~0.53 km3 (0.43 million acre feet, maf), accounting for ~4% of total state water consumption. High water withdrawals (32.3 km3, 26.2 maf) mostly reflect circulation between cooling ponds and power plants. About a third of the water withdrawals is not required for cooling and reflects circulation by idling plants being used as peaking plants. Controls on water consumption include (1) generator technology/thermal efficiency and (2) cooling system resulting in statewide consumption for natural gas combined cycle generators with mostly cooling towers being 60% lower than that of traditional coal, nuclear, or natural gas steam turbine generators with mostly cooling ponds. The primary control on water withdrawals is cooling system, with ~ two orders of magnitude lower withdrawals for cooling towers relative to once-through ponds statewide. Increases in natural gas combined cycle plants with cooling towers in response to high production of low-cost natural gas has greatly reduced water demand for thermoelectric cooling since 2000. A similar approach will be applied to thermoelectric generation throughout the US using information on fuel sources, generator technologies and cooling systems to better understand current water use for thermoelectric generation based on the legacy of past drivers and long lifespans of power plants. Understanding the historical evolution of water needs for thermoelectricity should allow us to better project future water needs.

Reedy, R. C.; Scanlon, B. R.

2013-12-01

85

Design and Numerical Simulation of a Symbiotic Thermoelectric Power Generation System Fed by a Low-Grade Heat Source  

NASA Astrophysics Data System (ADS)

All liquid heating systems, including solar thermal collectors and fossil-fueled heaters, are designed to convert low-temperature liquid to high-temperature liquid. In the presence of low- and high-temperature fluids, temperature differences can be created across thermoelectric devices to produce electricity so that the heat dissipated from the hot side of a thermoelectric device will be absorbed by the cold liquid and this preheated liquid enters the heating cycle and increases the efficiency of the heater. Consequently, because of the avoidance of waste heat on the thermoelectric hot side, the efficiency of heat-to-electricity conversion with this configuration is better than that of conventional thermoelectric power generation systems. This research aims to design and analyze a thermoelectric power generation system based on the concept described above and using a low-grade heat source. This system may be used to generate electricity either in direct conjunction with any renewable energy source which produces hot water (solar thermal collectors) or using waste hot water from industry. The concept of this system is designated "ELEGANT," an acronym from "Efficient Liquid-based Electricity Generation Apparatus iNside Thermoelectrics." The first design of ELEGANT comprised three rectangular aluminum channels, used to conduct warm and cold fluids over the surfaces of several commercially available thermoelectric generator (TEG) modules sandwiched between the channels. In this study, an ELEGANT with 24 TEG modules, referred to as ELEGANT-24, has been designed. Twenty-four modules was the best match to the specific geometry of the proposed ELEGANT. The thermoelectric modules in ELEGANT-24 were electrically connected in series, and the maximum output power was modeled. A numerical model has been developed, which provides steady-state forecasts of the electrical output of ELEGANT-24 for different inlet fluid temperatures.

Faraji, Amir Yadollah; Singh, Randeep; Mochizuki, Masataka; Akbarzadeh, Aliakbar

2014-06-01

86

High Efficiency Thermoelectric Generators Using New Very High Performance Materials  

NASA Astrophysics Data System (ADS)

Extensive theoretical and experimental studies have resulted in reasonable performance improvements (from an average ZT of 0.62 up to 0.75) of the state of the art high temperature SiGe thermoelectric materials in the last 5 years. However, significantly higher material conversion efficiencies are needed to make thermoelectrics competitive and economically attractive. A new approach that looks at radically different compounds and alloys was recently started at JPL and a new family of materials with great potential has been discovered. A real breakthrough was achieved when maximum ZT values of 2.0 were obtained to date on one of these materials in the 300-400C temperature range. Initial analysis of various experimental tests have confirmed its good mechanical and physico-chemical properties. Substantial increases in conversion efficiency and specific power are predicted (60-90%) by incorporating this new material into state of the art space nuclear power systems such as Radioisotope Thermoelectric Generators (RTG).

Fleurial, Jean-Pierre; Ewell, Richard; Caillat, Thierry; Vandersande, Jan

1994-07-01

87

New materials and devices for thermoelectric applications  

Microsoft Academic Search

New high efficiency thermoelectric materials with ZT values substantially larger than 1.0 have been recently developed. The successful development of a segmented thermoelectric generator utilizing a combination of state-of-the-art thermoelectric materials and these novel thermoelectric materials could result in a high thermal-to-electric materials conversion efficiency over 19%. This is because the new thermoelectric materials have a higher average ZT value

Jean-Pierre Fleurial; Alex Borshchevsky; Thierry Caillat; R. Ewell

1997-01-01

88

System and method to improve the power output and longetivity of a radioisotope thermoelectric generator  

DOEpatents

By using the helium generated by the alpha emissions of a thermoelectric generator during space travel for cooling, the thermal degradation of the thermoelectric generator can be slowed. Slowing degradation allows missions to be longer with little additional expense or payload.

Mowery, Jr., Alfred L. (Potomac, MD)

1993-01-01

89

System and method to improve the power output and longetivity of a radioisotope thermoelectric generator  

SciTech Connect

By using the helium generated by the alpha emissions of a thermoelectric generator during space travel for cooling the thermal degradation of the thermoelectric generator can be slowed. Slowing degradation allows missions to be longer with little additional expense or payload.

Mowery, A.L. Jr.

1992-12-31

90

Modular Analysis of Automobile Exhaust Thermoelectric Power Generation System  

NASA Astrophysics Data System (ADS)

In this paper, an automobile exhaust thermoelectric power generation system is packaged into a model with its own operating principles. The inputs are the engine speed and power, and the output is the power generated by the system. The model is divided into two submodels. One is the inlet temperature submodel, and the other is the power generation submodel. An experimental data modeling method is adopted to construct the inlet temperature submodel, and a theoretical modeling method is adopted to construct the power generation submodel. After modeling, simulation is conducted under various engine operating conditions to determine the variation of the power generated by the system. Finally, the model is embedded into a Honda Insight vehicle model to explore the energy-saving effect of the system on the vehicle under Economic Commission for Europe and cyc-constant_60 driving cycles.

Deng, Y. D.; Zhang, Y.; Su, C. Q.

2014-10-01

91

Fabrication of Flat Plate Solar Thermoelectric Generator Panels for Near-Earth Orbits  

Microsoft Academic Search

A practical thermomechanical configurational design was developed for flat plate thermoelectric generator unit couples (approximately 1 inch by 1 inch) and panels (approximately 3 inches by 3 inches). An account of the techniques used in fabricating these solar energy conversion devices is given. Resulting unit couples provide 3 watts\\/ft2 with a weight factor of 30 watts\\/lb for the couple and

F. K. Eggleston; N. Fuschillo

1965-01-01

92

A Thermoelectric Generator Using Porous Si Thermal Isolation  

PubMed Central

In this paper we report on a thermoelectric generator (TEG) using thermal isolation provided by a thick porous Si layer locally formed on the Si wafer and thermocouples composed of p-doped polycrystalline Si/Al. The “hot” contacts of the thermocouples lie on the porous Si layer, while the “cold” contacts lie on bulk crystalline Si. A housing was also designed and fabricated in order to transfer any external temperature change on the “hot” contacts of the thermocouples, the “cold” contacts being isolated from the “hot” contacts by a thick resist layer. The fabrication of the sensing element (Si die) is fully compatible with batch Si processing. The output power of the thermoelectric generator depends on the porous Si isolation layer thickness, porosity, structure and morphology. For a mesoporous Si layer of 60% porosity and a macroscopic temperature differential of 10 K, an output power of 0.39 ?W/cm2 was measured for a 50 ?m thick porous Si layer. PMID:24152923

Hourdakis, Emmanouel; Nassiopoulou, Androula G.

2013-01-01

93

Optimized working conditions for a thermoelectric generator as a topping cycle for gas turbines  

NASA Astrophysics Data System (ADS)

This paper presents a model for a theoretical maximum efficiency of a thermoelectric generator integrated with a Brayton-cycle engine. The thermoelectric cycle is presented in two configurations as a topping cycle and a preheating topping cycle. For the topping cycle configuration, the thermoelectric generator receives heat from a high-temperature heat source and produces electrical work before rejecting heat to a Brayton cycle. For the preheating topping cycle, the rejected heat from the thermoelectric generator partially heats the compressed working fluid of the Brayton cycle before a secondary heater delivers heat to the working fluid directly from the heat source. The thermoelectric topping cycle efficiency increases as the temperature difference between the hot- and cold-side increases; however, this limits the heat transfer possible to the Brayton cycle, which in turn reduces power generation from the Brayton cycle. This model identifies the optimum operating parameters of the thermoelectric and Brayton cycles to obtain the maximum thermal efficiency of the combined cycle. In both configurations, efficiency gains are larger at low-temperature Brayton cycles. Although a thermoelectric generator (TEG) topping cycle enhances efficiency for a low temperature turbine, efficiency cannot exceed a high temperature gas turbine. Using a TEG topping cycle is limited to cases when space or price for a high temperature turbine cannot be justified. A design to achieve the preheating thermoelectric topping cycle is also presented.

Brady Knowles, C.; Lee, Hohyun

2012-10-01

94

Characteristics of ? thin-film thermoelectric devices for power generation  

NASA Astrophysics Data System (ADS)

The characteristics of flash-deposited 0957-0233/8/6/013/img6 and 0957-0233/8/6/013/img7 thin-film thermoelectric generators are described. The overall Seebeck coefficient for a single couple in the generator (0957-0233/8/6/013/img6 forming the n-type thermoelement and 0957-0233/8/6/013/img9 forming the p-type element) is 0957-0233/8/6/013/img10. This value approaches the figures presented for these materials in bulk form. The results demonstrate how the parameters of the generator can be altered in order to maximize generation efficiency. For example, doubling the cross sectional area of the thermoelement can result in a two-fold increase in the output power. Extrapolation of the results indicates that a generator of dimensions 0957-0233/8/6/013/img11 can provide a voltage source sufficiently powerful to drive a microelectronic circuit (namely 3 - 5 V at about 0957-0233/8/6/013/img12). Hence, potentially, the generator could be used in place of a battery unit in small-scale generation applications, where a source of waste heat is available.

Kiely, J. H.; Lee, Dong-Hi

1997-06-01

95

Development Status and Plans of the Advanced Thermoelectric Converter (ATEC) Project  

NASA Technical Reports Server (NTRS)

Advances in thermoelectric materials with high ZT in mid-90's, revived interest in advanced thermoelectric materials at DOE, DOD and NASA NASA. JPL, in collaboration with Universities, identified promising high temperature thermoelectric materials for potential use in next generation RTGs nder DOD and NASA funding (1995 to 2005). Based on these advances the ATEC project was initiated in January 2006 to develop an advanced converter by 2010 (10-12% couple efficiency). ATEC is a technology maturation project with an off-ramp to a proposed Advanced RTG (ARTG) providing 6-8 W/kg and 8-10% system efficiency to support potential future SMD missions as early as 2017. In addition, work is continuing on advancing the TE materials technology to support development of an RTG with 12-14 W/kg and 15 to 20% efficiency by 2020.

Ewell, Richard; Caillat, Thierry

2008-01-01

96

High efficiency thermoelectric power generation using Zintl-type materials  

NASA Technical Reports Server (NTRS)

The invention disclosed herein relates to thermoelectrically-active p-type Zintl phase materials as well as devices utilizing such compounds. Such thermoelectric materials and devices may be used to convert thermal energy into electrical energy, or use electrical energy to produce heat or refrigeration. Embodiments of the invention relate to p-type thermoelectric materials related to the compound Yb.sub.14MnSb.sub.11.

Snyder, G. Jeffrey (Inventor); Gascoin, Franck (Inventor); Brown, Shawna (Inventor); Kauzlarich, Susan (Inventor)

2010-01-01

97

Fabrication and characterization of CMOS-MEMS thermoelectric micro generators.  

PubMed

This work presents a thermoelectric micro generator fabricated by the commercial 0.35 ?m complementary metal oxide semiconductor (CMOS) process and the post-CMOS process. The micro generator is composed of 24 thermocouples in series. Each thermocouple is constructed by p-type and n-type polysilicon strips. The output power of the generator depends on the temperature difference between the hot and cold parts in the thermocouples. In order to prevent heat-receiving in the cold part in the thermocouples, the cold part is covered with a silicon dioxide layer with low thermal conductivity to insulate the heat source. The hot part of the thermocouples is suspended and connected to an aluminum plate, to increases the heat-receiving area in the hot part. The generator requires a post-CMOS process to release the suspended structures. The post-CMOS process uses an anisotropic dry etching to remove the oxide sacrificial layer and an isotropic dry etching to etch the silicon substrate. Experimental results show that the micro generator has an output voltage of 67 ?V at the temperature difference of 1 K. PMID:22205869

Kao, Pin-Hsu; Shih, Po-Jen; Dai, Ching-Liang; Liu, Mao-Chen

2010-01-01

98

A Thermoelectric Generator Using Engine Coolant for Light-Duty Internal Combustion Engine-Powered Vehicles  

NASA Astrophysics Data System (ADS)

We proposed and fabricated a thermoelectric generator (TEG) using the engine water coolant of passenger vehicles. The experimental results revealed that the maximum output power from the proposed thermoelectric generator was ~75 W, the calculated thermoelectric module efficiency of the TEG was ~2.1%, and the overall efficiency of electric power generation from the waste heat of the engine coolant was ~0.3% in the driving mode at 80 km/h. The conventional radiator can thus be replaced by the proposed TEG without additional devices or redesign of the engine water cooling system of the existing radiator.

Kim, Shiho; Park, Soonseo; Kim, Sunkook; Rhi, Seok-Ho

2011-05-01

99

Complex thermoelectric materials  

Microsoft Academic Search

Thermoelectric materials, which can generate electricity from waste heat or be used as solid-state Peltier coolers, could play an important role in a global sustainable energy solution. Such a development is contingent on identifying materials with higher thermoelectric efficiency than available at present, which is a challenge owing to the conflicting combination of material traits that are required. Nevertheless, because

Eric S. Toberer; G. Jeffrey Snyder

2008-01-01

100

Study of a thermoelectric system equipped with a maximum power point tracker for stand-alone electric generation.  

NASA Astrophysics Data System (ADS)

According to the International Energy Agency, 1.4 billion people are without electricity in the poorest countries and 2.5 billion people rely on biomass to meet their energy needs for cooking in developing countries. The use of cooking stoves equipped with small thermoelectric generator to provide electricity for basic needs (LED, cell phone and radio charging device) is probably a solution for houses far from the power grid. The cost of connecting every house with a landline is a lot higher than dropping thermoelectric generator in each house. Thermoelectric generators have very low efficiency but for isolated houses, they might become really competitive. Our laboratory works in collaboration with plane`te-bois (a non governmental organization) which has developed energy-efficient multifunction (cooking and hot water) stoves based on traditional stoves designs. A prototype of a thermoelectric generator (Bismuth Telluride) has been designed to convert a small part of the energy heating the sanitary water into electricity. This generator can produce up to 10 watts on an adapted load. Storing this energy in a battery is necessary as the cooking stove only works a few hours each day. As the working point of the stove varies a lot during the use it is also necessary to regulate the electrical power. An electric DC DC converter has been developed with a maximum power point tracker (MPPT) in order to have a good efficiency of the electronic part of the thermoelectric generator. The theoretical efficiency of the MMPT converter is discussed. First results obtained with a hot gas generator simulating the exhaust of the combustion chamber of a cooking stove are presented in the paper.

Favarel, C.; Champier, D.; Bédécarrats, J. P.; Kousksou, T.; Strub, F.

2012-06-01

101

Heat exchanger design for thermoelectric electricity generation from low temperature flue gas streams  

E-print Network

An air-to-oil heat exchanger was modeled and optimized for use in a system utilizing a thermoelectric generator to convert low grade waste heat in flue gas streams to electricity. The NTU-effectiveness method, exergy, and ...

Latcham, Jacob G. (Jacob Greco)

2009-01-01

102

On the Use of Thermoelectric (TE) Applications Based on Commercial Modules: The Case of TE Generator and TE Cooler  

Microsoft Academic Search

In recent years, thermoelectricity sees rapidly increasing usages in applications like portable refrigerators, beverage coolers, electronic component coolers etc. when used as Thermoelectric Cooler (TEC), and Thermoelectric Generators (TEG) which make use of the Seebeck effect in semiconductors for the direct conversion of heat into electrical energy and is of particular interest for systems of highest reliability or for waste

K. Zorbas; E. Hatzikraniotis; K. M. Paraskevopoulos; Th. Kyratsi

2010-01-01

103

New approaches to interfacing thermoelectric generators to the load bus in a nuclear space vehicle  

E-print Network

NEW APPROACHES TO INTERFACING THERMOELECTRIC GENERATORS TO THE LOAD BUS IN A NUCLEAR SPACE VEHICLE A Thesis PAUL LEROY BROHLIN Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1988 Major Subject: Electrical Engineering NEW APPROACHES TO INTERFACING THERMOELECTRIC GENERATORS TO THE LOAD BUS IN A NUCLEAR SPACE VEHICLE A Thesis PAUL LEROY BROHLIN Approved as to style and content by...

Brohlin, Paul LeRoy

2012-06-07

104

Wearable thermoelectric generator for harvesting human body heat energy  

NASA Astrophysics Data System (ADS)

This paper presents the realization of a wearable thermoelectric generator (TEG) in fabric for use in clothing. A TEG was fabricated by dispenser printing of Bi0.5Sb1.5Te3 and Bi2Se0.3Te2.7 in a polymer-based fabric. The prototype consisted of 12 thermocouples connected by conductive thread over an area of 6 × 25 mm2. The device generated a power of 224 nW for a temperature difference of 15 K. When the TEG was used on the human body, the measured output power was 224 nW in an ambient temperature of 5 °C. The power of the TEG was affected by the movement of the wearer. A higher voltage was maintained while walking than in a stationary state. In addition, the device did not deform after it was bent and stretched several times. The prospect of using the TEG in clothing applications was confirmed under realistic conditions.

Kim, Min-Ki; Kim, Myoung-Soo; Lee, Seok; Kim, Chulki; Kim, Yong-Jun

2014-10-01

105

Transitioning to Zero Freshwater Withdrawal for Thermoelectric Generation  

NASA Astrophysics Data System (ADS)

The electricity sector is the largest withdrawer of freshwater in the United States. The primary demand for water from the electricity sector is for cooling thermoelectric power plants. Droughts and potential changes in water resources resulting from climate change pose important risks to thermoelectric power production in the United States. Power plants can minimize risk in a variety of ways. One method of reducing risk is to move away from dependency on freshwater resources. Here a scoping level analysis is performed to identify the technical tradeoffs and initial cost estimates for retrofitting all existing steam-powered generation to achieve zero freshwater withdrawal. Specifically, the conversion of existing freshwater-cooled plants to dry cooling or a wet cooling system utilizing non-potable water is considered. The least cost alternative is determined for each of the 1,178 freshwater using power plants in the United States. The use of non-potable water resources, such as municipal wastewater and shallow brackish groundwater, is considered based on the availability and proximity of those resources to the power plant, as well as the costs to transport and treat those resources to an acceptable level. The projected increase in levelized cost of electricity due to power plant retrofits ranges roughly from 0.20 to 20/MWh with a median value of 3.53/MWh. With a wholesale price of electricity running about 35/MWh, many retrofits could be accomplished at levels that would add less than 10% to current power plant generation expenses. Such retrofits could alleviate power plant vulnerabilities to thermal discharge limits in times of drought (particularly in the East) and would save 3.2 Mm3/d of freshwater consumption in watersheds with limited water availability (principally in the West). The estimated impact of retrofits on wastewater and brackish water supply is minimal requiring only a fraction of the available resource. Total parasitic energy requirements to achieve zero freshwater withdrawal are estimated at 140 million MWh or roughly 4.5% of the initial production from the retrofitted plants.

Macknick, J.; Tidwell, V. C.; Zemlick, K. M.; Sanchez, J.; Woldeyesus, T.

2013-12-01

106

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

PubMed

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. PMID:21793542

Yazawa, Kazuaki; Shakouri, Ali

2011-09-01

107

Oxide based thermoelectric materials for large scale power generation  

E-print Network

The thermoelectric (TE) devices are based on the Seebeck and Peltier effects, which describe the conversion between temperature gradient and electricity. The effectiveness of the material performance can be described by ...

Song, Yang, M. Eng. Massachusetts Institute of Technology

2008-01-01

108

Thermal vacuum life test facility for radioisotope thermoelectric generators  

SciTech Connect

In the late 1970's, the Department of Energy (DOE) assigned Monsanto Research Corporation, Mound Facility, now operated by EG G Mound Applied Technologies, the responsibility for assembling and testing General Purpose Heat Source (GPHS) radioisotope thermoelectric generators (RTGs). Assembled and tested were five RTGs, which included four flight units and one non-flight qualification unit. Figure 1 shows the RTG, which was designed by General Electric AstroSpace Division (GE/ASD) to produce 285 W of electrical power. A detailed description of the processes for RTG assembly and testing is presented by Amos and Goebel (1989). The RTG performance data are described by Bennett, et al. (1986). The flight units will provide electrical power for the National Aeronautics and Space Administration's (NASA) Galileo mission to Jupiter (two RTGs) and the joint NASA/European Space Agency (ESA) Ulysses mission to study the polar regions of the sun (one RTG). The remaining flight unit will serve as the spare for both missions, and a non-flight qualification unit was assembled and tested to ensure that performance criteria were adequately met. 4 refs., 3 figs.

Deaton, R.L.; Goebel, C.J.; Amos, W.R.

1990-01-01

109

Individual Module Maximum Power Point Tracking for Thermoelectric Generator Systems  

NASA Astrophysics Data System (ADS)

In a thermoelectric generator (TEG) system the DC/DC converter is under the control of a maximum power point tracker which ensures that the TEG system outputs the maximum possible power to the load. However, if the conditions, e.g., temperature, health, etc., of the TEG modules are different, each TEG module will not produce its maximum power. If each TEG module is controlled individually, each TEG module can be operated at its maximum power point and the TEG system output power will therefore be higher. In this work a power converter based on noninverting buck-boost converters capable of handling four TEG modules is presented. It is shown that, when each module in the TEG system is operated under individual maximum power point tracking, the system output power for this specific application can be increased by up to 8.4% relative to the situation when the modules are connected in series and 16.7% relative to the situation when the modules are connected in parallel.

Vadstrup, Casper; Schaltz, Erik; Chen, Min

2013-07-01

110

Truck co-generation system based on combustion heated thermoelectric conversion  

SciTech Connect

Among the micro-co-generation systems using direct conversion of combustion heat into electricity (thermionic, thermoelectric converters) and fuel cells with an electric power of up to several kW, only the thermoelectric co-generation systems have a demonstrated life-time of up to 10 years. This is one of the most important factors making these systems a more likely commercialization candidate. The report deals with a conceptual design of a combustion heated thermoelectric cogeneration system to be applied in vehicles (truck, trailer, yacht, etc.). The authors named these systems the Thermoelectric Transport Co-generation Systems (TTCS). The report is concerned with one example of these systems--the Thermoelectric Truck Co-generation System (TT-kCS) designed to support the lives of both the driver and the car, when operating in the northern regions. In particular, the TT-kCS should provide the start-up of the cold engine of a truck at an ambient temperature of down to 50 C below zero and create comfortable conditions for a driver during the long-term halts and in emergency situations. The estimates made for a standard truck with an engine of 210 HP employed in Russia showed that the TT-kCS should generate {approximately}600 W of electrical power and {approximately}18 kW of heat. The report deals with two options for the thermoelectric converter design: one of them using the planar geometry of thermoelectric batteries, and the other one using a radial-cylindrical thermoelectric battery configuration. The economic feasibility of the TT-kCS application is based on a considerable reduction in fuel consumption of the TT-kCS equipped truck as compared to that of a conventional truck when the engine is idling. Another advantage is the prolongation of the engine`s service life.

Meleta, Ye.A.; Yarygin, V.I.; Klepikov, V.V. [State Scientific Center of Russian Federation, Obninsk (Russian Federation). Inst. of Physics and Power Engineering; Wolff, L.R. [Energy Conversion Systems B.V., Eindhoven (Netherlands)

1997-12-31

111

Micro/Nano Fabricated Solid-State Thermoelectric Generator Devices for Integrated High Voltage Power Sources  

NASA Astrophysics Data System (ADS)

Deep space missions have a strong need for compact, high power density, reliable and long life electrical power generation and storage under extreme temperature conditions. Except for electrochemical batteries and solar cells, there are currently no available miniaturized power sources. Conventional power generators devices become inefficient in extreme environments (such as encountered in Mars, Venus or outer planet missions) and rechargeable energy storage devices can only be operated in a narrow temperature range thereby limiting mission duration. The planned development of much smaller spacecrafts incorporating a variety of micro/nanodevices and miniature vehicles will require novel, reliable power technologies. It is also expected that such micro power sources could have a wide range of terrestrial applications, in particular when the limited lifetime and environmental limitations of batteries are key factors. Advanced solid-state thermoelectric combined with radioisotope or waste heat sources and low profile energy storage devices are ideally suited for these applications. The Jet Propulsion Laboratory has been actively pursuing the development of thermoelectric micro/nanodevices that can be fabricated using a combination of electrochemical deposition and integrated circuit processing techniques. Some of the technical challenges associated with these micro/nanodevice concepts, their expected level of performance and experimental fabrication and testing results to date are presented and discussed.

Fleurial, J.-P.; Ryan, M. A.; Snyder, G. J.; Huang, C.-K.; Whitacre, J. F.; Patel, J.; Lim, J.; Borshchevsky, A.

2002-01-01

112

Object-Oriented Modeling of an Energy Harvesting System Based on Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

This paper deals with the modeling of an energy harvesting system based on thermoelectric generators (TEG), and the validation of the model by means of a test bench. TEGs are capable to improve the overall energy efficiency of energy systems, e.g. combustion engines or heating systems, by using the remaining waste heat to generate electrical power. Previously, a component-oriented model of the TEG itself was developed in Modelica® language. With this model any TEG can be described and simulated given the material properties and the physical dimension. Now, this model was extended by the surrounding components to a complete model of a thermoelectric energy harvesting system. In addition to the TEG, the model contains the cooling system, the heat source, and the power electronics. To validate the simulation model, a test bench was built and installed on an oil-fired household heating system. The paper reports results of the measurements and discusses the validity of the developed simulation models. Furthermore, the efficiency of the proposed energy harvesting system is derived and possible improvements based on design variations tested in the simulation model are proposed.

Nesarajah, Marco; Frey, Georg

113

Some issues of history and prospects of thermoelectricity  

NASA Astrophysics Data System (ADS)

This work analyzes the approaches that had led to the discovery of thermoelectricity and a generalized approach in the description of thermoelectric power conversion based on the induction of thermoelectric currents. Possibilities of thermal generators contribution to ``green'' technologies, in particular, to waste heat recovery from heat engines are analyzed. Tellurium problem and the ways of tackling it are considered. Attention is focused on the efficiency of computer methods for designing thermoelectric devices. The outlook for progress of thermoelectricity in measuring technique is considered. The information on the organizations and specialists in thermoelectricity is provided. The necessity of purposeful training specialists in thermoelectricity for its more successful development is emphasized.

Anatychuk, L.

2012-06-01

114

Micro/nanofabricated solid-state thermoelectric generator devices for integrated high voltage power sources  

NASA Technical Reports Server (NTRS)

The Jet Propulsion Laboratory has been actively pursuing the development of thermoelectric micro/nanodevices that can be fabricated using a combination of electrochemical deposition and integrated circuit processing techniques.

Fleurial, J. P.; Snyder, G. J.; Patel, J.; Huang, C. K.; Ryan, M. A.; Averback, R.; Chen, G.; Hill, C.

2002-01-01

115

Thermoelectric MEMS generators as a power supply for a body area network  

Microsoft Academic Search

Miniaturized and cost-effective thermoelectric generators (TEG) scavenging energy from environment could potentially provide power autonomy to consumer electronic products operating at low power. For example, TEG mounted in a wristwatch have been used to generate electricity from human heat. The key point of IMEC's research in this field is the realization of a body area network, consisting of a set

V. Leonov; P. Fiorini; S. Sedky; T. Torfs; C. Van Hoof

2005-01-01

116

Flexible and lightweight thermoelectric generators composed of carbon nanotube-polystyrene composites printed on film substrate  

NASA Astrophysics Data System (ADS)

A flexible thermoelectric generator (TEG) was fabricated on a polyethylene naphthalate film substrate using a printing process. The thermoelectric material used in this study, a composite material consisting of carbon nanotubes (CNTs) and polystyrene, contained approximately 35 vol. % of voids. Because of the reduction in the density of the CNT-polystyrene composite caused by the voids, the TEG was remarkably lightweight (weight per unit area: ?15.1 mg/cm2). The TEG generated approximately 55 mW/m2 of power at a temperature difference of 70 °C.

Suemori, Kouji; Hoshino, Satoshi; Kamata, Toshihide

2013-10-01

117

A compendium of the radioisotope thermoelectric generator transportation system and recent programmatic changes  

SciTech Connect

Because RTGs contain significant quantities of radioactive materials, usually plutonium-238 and its decay products, they must be transported in packages built in accordance with 10 CFR 71 (1994). To meet these regulatory requirements, US DOE commissioned Westinghouse Hanford Co. in 1988 to develop a Radioisotope Thermoelectric Generator Transportation System (RTGTS) that would fully comply while protecting RTGs from adverse environmental conditions during normal transport conditions (eg, mainly shock and heat). RTGTS is scheduled for completion Dec. 1996 and will be available to support NASA`s Cassini mission to Saturn in Oct. 1997. This paper provides an overview of the RTGTS project, discusses the hardware being produced, and summarizes various programmatic and management innovations required by recent changes at DOE.

Becker, D.L.; McCoy, J.C.

1996-03-01

118

Certification testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container  

SciTech Connect

The Heat Source/Radioisotopic Thermoelectric Generator shipping counter is a Type B packaging currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to normal and hypothetical accident environments defined in Title 10 of the Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this packaging design. This report documents the testing portion of the design verification. Six tests were conducted on a prototype package: a water spray test, a 4-foot normal conditions drop test, a 30-foot drop test, a 40-inch puncture test, a 30-minute thermal test, and an 8-hour immersion test.

Bronowski, D.R.; Madsen, M.M.

1991-09-01

119

Structural testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container  

SciTech Connect

The Heat Source/Radioisotopic Thermoelectric Generator shipping container is a Type B packaging design currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to the normal and hypothetical accident environments defined in Title 10 Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this package design. This report documents the test program portion of the design verification, using several prototype packages. Four types of testing were performed: 30-foot hypothetical accident condition drop tests in three orientations, 40-inch hypothetical accident condition puncture tests in five orientations, a 21 psi external overpressure test, and a normal conditions of transport test consisting of a water spray and a 4 foot drop test. 18 refs., 104 figs., 13 tabs.

Bronowski, D.R.; Madsen, M.M.

1991-06-01

120

Controls on water use for thermoelectric generation: case study Texas, US.  

PubMed

Large-scale U.S. dependence on thermoelectric (steam electric) generation requiring water for cooling underscores the need to understand controls on this water use. The study objective was to quantify water consumption and withdrawal for thermoelectric generation, identifying controls, using Texas as a case study. Water consumption for thermoelectricity in Texas in 2010 totaled ?0.43 million acre feet (maf; 0.53 km(3)), accounting for ?4% of total state water consumption. High water withdrawals (26.2 maf, 32.3 km(3)) mostly reflect circulation between ponds and power plants, with only two-thirds of this water required for cooling. Controls on water consumption include (1) generator technology/thermal efficiency and (2) cooling system, resulting in statewide consumption intensity for natural gas combined cycle generators with mostly cooling towers (0.19 gal/kWh) being 63% lower than that of traditional coal, nuclear, or natural gas steam turbine generators with mostly cooling ponds (0.52 gal/kWh). The primary control on water withdrawals is cooling system, with ?2 orders of magnitude lower withdrawals for cooling towers relative to once-through ponds statewide. Increases in natural gas combined cycle plants with cooling towers in response to high production of low-cost natural gas has greatly reduced water demand for thermoelectric cooling since 2000. PMID:23937226

Scanlon, Bridget R; Reedy, Robert C; Duncan, Ian; Mullican, William F; Young, Michael

2013-10-01

121

Design, Modeling, Fabrication, and Evaluation of Thermoelectric Generators with Hot-Wire Chemical Vapor Deposited Polysilicon as Thermoelement Material  

NASA Astrophysics Data System (ADS)

This paper presents the design, modeling, fabrication, and evaluation of thermoelectric generators (TEGs) with p-type polysilicon deposited by hot-wire chemical vapor deposition (HWCVD) as thermoelement material. A thermal model is developed based on energy balance and heat transfer equations using lumped thermal conductances. Several test structures were fabricated to allow characterization of the boron-doped polysilicon material deposited by HWCVD. The film was found to be electrically active without any post-deposition annealing. Based on the tests performed on the test structures, it is determined that the Seebeck coefficient, thermal conductivity, and electrical resistivity of the HWCVD polysilicon are 113 ?V/K, 126 W/mK, and 3.58 × 10-5 ? m, respectively. Results from laser tests performed on the fabricated TEG are in good agreement with the thermal model. The temperature values derived from the thermal model are within 2.8% of the measured temperature values. For a 1-W laser input, an open-circuit voltage and output power of 247 mV and 347 nW, respectively, were generated. This translates to a temperature difference of 63°C across the thermoelements. This paper demonstrates that HWCVD, which is a cost-effective way of producing solar cells, can also be applied in the production of TEGs. By establishing that HWCVD polysilicon can be an effective thermoelectric material, further work on developing photovoltaic-thermoelectric (PV-TE) hybrid microsystems that are cost-effective and better performing can be explored.

de Leon, Maria Theresa; Tarazona, Antulio; Chong, Harold; Kraft, Michael

2014-11-01

122

Design, Modeling, Fabrication, and Evaluation of Thermoelectric Generators with Hot-Wire Chemical Vapor Deposited Polysilicon as Thermoelement Material  

NASA Astrophysics Data System (ADS)

This paper presents the design, modeling, fabrication, and evaluation of thermoelectric generators (TEGs) with p-type polysilicon deposited by hot-wire chemical vapor deposition (HWCVD) as thermoelement material. A thermal model is developed based on energy balance and heat transfer equations using lumped thermal conductances. Several test structures were fabricated to allow characterization of the boron-doped polysilicon material deposited by HWCVD. The film was found to be electrically active without any post-deposition annealing. Based on the tests performed on the test structures, it is determined that the Seebeck coefficient, thermal conductivity, and electrical resistivity of the HWCVD polysilicon are 113 ?V/K, 126 W/mK, and 3.58 × 10-5 ? m, respectively. Results from laser tests performed on the fabricated TEG are in good agreement with the thermal model. The temperature values derived from the thermal model are within 2.8% of the measured temperature values. For a 1-W laser input, an open-circuit voltage and output power of 247 mV and 347 nW, respectively, were generated. This translates to a temperature difference of 63°C across the thermoelements. This paper demonstrates that HWCVD, which is a cost-effective way of producing solar cells, can also be applied in the production of TEGs. By establishing that HWCVD polysilicon can be an effective thermoelectric material, further work on developing photovoltaic-thermoelectric (PV-TE) hybrid microsystems that are cost-effective and better performing can be explored.

de Leon, Maria Theresa; Tarazona, Antulio; Chong, Harold; Kraft, Michael

2014-08-01

123

Operational readiness review plan for the radioisotope thermoelectric generator materials production tasks  

Microsoft Academic Search

In October 1989, a Space Shuttle lifted off from Cape Kennedy carrying the spacecraft Galileo on its mission to Jupiter. In November 1990, a second spacecraft, Ulysses, will be launched from Cape Kennedy with a mission to study the polar regions of the sun. The prime source of power for both spacecraft is a series of radioisotope thermoelectric generators (RTG's),

R. H. Cooper; M. M. Martin; C. R. Riggs; R. L. Beatty; E. K. Ohriner; R. N. Escher

1990-01-01

124

Thermoelectric generator and solid-state battery for stand-alone microsystems  

Microsoft Academic Search

This paper presents a thermoelectric (TE) generator and a solid-state battery for powering microsystems. Prototypes of TE generators were fabricated and characterized. The TE generator is a planar microstructure based on thin films of n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3), which were deposited using co-evaporation. The measurements on selected samples of Bi2Te3 and Sb2Te3 thin films indicated

J. P. Carmo; J. F. Ribeiro; M. F. Silva; L. M. Goncalves; J. H. Correia

2010-01-01

125

Novel thermoelectric materials development, existing and potential applications, and commercialization routes  

E-print Network

Thermoelectrics (TE) are devices which can convert heat in the form of a temperature gradient into electricity, or alternatively generate and absorb heat when an electrical current is run through them. It was established ...

Bertreau, Philippe

2006-01-01

126

Low power thermoelectric generator-self-sufficient energy supply for micro systems  

Microsoft Academic Search

New micro and sensor systems are being rapidly developed for their application in all technology events in future. The energy consumption of systems incorporated the latest technical advances decreases permanently to the range of only ?W. For the applications in this low power range (a few 10 ?W), DTS has developed a new self-sufficient power supply the low power thermoelectric

Matthias Stordeur; Ingo Stark

1997-01-01

127

Thermoelectric Power Generation Utilizing the Waste Heat from a Biomass Boiler  

NASA Astrophysics Data System (ADS)

The objective of the presented work is to test the possibility of using thermoelectric power to convert flue gas waste heat from a small-scale domestic pellet boiler, and to assess the influence of a thermoelectric generator on its function. A prototype of the generator, able to be connected to an existing device, was designed, constructed, and tested. The performance of the generator as well as the impact of the generator on the operation of the boiler was investigated under various operating conditions. The boiler gained auxiliary power and could become a combined heat and power unit allowing self-sufficient operation. The created unit represents an independent source of electricity with effective use of fuel.

Brazdil, Marian; Pospisil, Jiri

2013-07-01

128

Complex oxides useful for thermoelectric energy conversion  

DOEpatents

The invention provides for a thermoelectric system comprising a substrate comprising a first complex oxide, wherein the substrate is optionally embedded with a second complex oxide. The thermoelectric system can be used for thermoelectric power generation or thermoelectric cooling.

Majumdar, Arunava (Orinda, CA); Ramesh, Ramamoorthy (Moraga, CA); Yu, Choongho (College Station, TX); Scullin, Matthew L. (Berkeley, CA); Huijben, Mark (Enschede, NL)

2012-07-17

129

Magnesium and Manganese Silicides For Efficient And Low Cost Thermo-Electric Power Generation  

SciTech Connect

Thermoelectric Power Generation (TEPG) is the most efficient and commercially deployable power generation technology for harvesting wasted heat from such things as automobile exhausts, industrial furnaces, and incinerators, and converting it into usable electrical power. We investigated the materials magnesium silicide (Mg2Si) and manganese silicide (MnSi) for TEG. MgSi2 and MnSi are environmentally friendly, have constituent elements that are abundant in the earth's crust, non-toxic, lighter and cheaper. In Phase I, we successfully produced Mg2Si and MnSi material with good TE properties. We developed a novel technique to synthesize Mg2Si with good crystalline quality, which is normally very difficult due to high Mg vapor pressure and its corrosive nature. We produced n-type Mg2Si and p-type MnSi nanocomposite pellets using FAST. Measurements of resistivity and voltage under a temperature gradient indicated a Seebeck coefficient of roughly 120 V/K on average per leg, which is quite respectable. Results indicated however, that issues related to bonding resulted in high resistivity contacts. Determining a bonding process and bonding material that can provide ohmic contact from room temperature to the operating temperature is an essential part of successful device fabrication. Work continues in the development of a process for reproducibly obtaining low resistance electrical contacts.

Trivedi, Sudhir B. [Brimrose Technology Corporation; Kutcher, Susan W. [Brimrose Technology Corporation; Rosemeier, Cory A. [Brimrose Technology Corporation; Mayers, David [Brimrose Technology Corporation; Singh, Jogender [Pennsylvania State University

2013-12-02

130

THERMOELECTRIC GENERATION OF CHARGE IMBALANCE AT A SUPERCONDUCTOR-NORMAL METAL INTERFACE  

SciTech Connect

The thermoelectric voltage produced across a superconductor-normal metal-superconductor (SNS) sandwich by an applied heat current has been measured in Pb-Cu-PbBi and In-Al-Sn as a function of temperature. The observed divergence of the thermoelectric voltage near T{sub c} is attributed to a charge imbalance region decaying into the superconductor from the NS interface over the quasiparticle diffusion length {lambda}{sub Q*}. The charge imbalance is generated by thermoelectrically driven quasiparticle currents in the superconductor. It contributes a voltage per unit heat power given by V{sub s}/P = {lambda}{sub Q*}S/{kappa}A, where A is the sample cross-sectional area, and S and {kappa} are the thermopower and the thermal conductivity of quasiparticles in the superconductor. For Pb and In, we find the measured thermopower in the superconducting state to be slowly-varying with temperature near T{sub c} and consistent in magnitude with normal state values. This result is in agreement with theoretical predictions of thermoelectric effects in superconductors but contrary to previous experimental results obtained by other methods.

Van Harlingen, D.J.

1981-01-01

131

Thermoelectric generation of charge imbalance at a superconductor-normal metal interface  

SciTech Connect

The thermoelectric voltage produced across a superconductor--normal--metal--superconductor (SNS) sandwich by an applied heat current has been measured in Pb--Cu--PbBi and In--Al--Sn as a function of temperature. The observed divergence of the thermoelectric voltage near T/sub c/ is attributed to a charge imbalance region decaying into the superconductor from the NS interface over the quasiparticle diffusion length lambda/sub Q/ +- . The charge imbalance is generated by thermoelectrically driven quasiparticle currents in the super-conductor. It contributes a voltage per unit heat power given by V/sub s//P = lambda/sub Q/ +- S//sub kappa/A, where A is the sample cross-sectional area, and S and kappa are the thermopower and the thermal conductivity of quasiparticles in the super conductor. For Pb and In, we find the measured thermopower in the super-conducting state to be slowly varying with temperature near T/sub c/ and consistent in magnitude with normal state values. This results is in agreement with theoretical predictions of thermoelectric effects in superconductors but contrary to previous experimental results obtained by other methods.

Van Harlingen, D.J.

1981-07-01

132

Reply to the Comment on "Optimal working conditions for thermoelectric generators with realistic thermal coupling" by S. Su et al  

E-print Network

We reply to the comment made by Su et al. on "Optimal working conditions for thermoelectric generators with realistic thermal coupling". In particular we justify the efficiency definition used in the main paper.

Apertet, Y; Glavatskaya, O; Goupil, C; Lecoeur, P; 10.1209/0295-5075/101/68008

2013-01-01

133

Thermoelectric Devices Cool, Power Electronics  

NASA Technical Reports Server (NTRS)

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.

2009-01-01

134

Freshwater Availability and Constraints on Thermoelectric Power Generation in the Southeast U.S.  

SciTech Connect

There is a myriad of uses to which our country's freshwater supply is currently committed. Together with increasing quantities of consumption, there are growing constraints on water availability. In our future there will be two elements of consumption at the forefront of concern: availability and efficiency. Availability of freshwater is the most important of these and is the subject of this report. To use water efficiently, we must first have it. Efficiency is key to ensuring availability for future needs. As population grows and economic and technology demands increase - especially for thermoelectric power - needs for freshwater will also increase. Thus, using our limited supplies of freshwater must be done as efficiently as possible. Thermoelectric generating industry is the largest user of our nation's water resources, including fresh, surface, ground, and saline water. Saline water use accounts for approximately 30% of thermoelectric use, while the remaining 70% is from freshwater sources. The U.S. Geological Survey (USGS) estimates that thermoelectric generation accounts for roughly 136,000 million gallons per day (MGD), or 39% of freshwater withdrawals. This ranks slightly behind agricultural irrigation as the top source of freshwater withdrawals in the U.S. in 2000. For Americans to preserve their standard of living and maintain a thriving economy it is essential that greater attention be paid to freshwater availability in efforts to meet energy demands - particularly for electric power. According to projections by the Energy Information Administration's (EIA) Annual Energy Outlook 2006 (AEO 2006) anticipated growth of thermoelectric generating capacity will be 22% between 2005 and 2030. In the 2007 Report, EIA estimates that capacity to grow from approximately 709 GW in 2005 to 862 GW in 20303. These large increases in generating capacity will result in increased water demands by thermoelectric power plants and greater competition over water between the energy sector and domestic, commercial, agricultural, industrial, and instream use sectors. The implications of these increased demands have not been adequately researched. This report is a preliminary effort to explore these implications. In addition, since this report was completed in draft form in 2007, there have been several updates and important issues brought to bear on water for energy that should be mentioned. Uncertainties include drought and climate change impacts. Policies such as commitments to Coal-to-Liquids (CTL) quotas; Ethanol production requirements; Carbon Capture and Storage (CCS) mandates; increasing nuclear power plant construction; valuing carbon and carbon dioxide emissions all have significant implications on water use and on the need for water in the power sector by 2025.

David Feldman; Amanda Slough; Gary Garrett

2008-06-01

135

Over-the-road shock and vibration testing of the radioisotope thermoelectric generator transportation system  

SciTech Connect

Radioisotope Thermoelectric Generators (RTG) convert heat generated by radioactive decay into electricity through the use of thermocouples. The RTGs have a long operating life, are reasonably lightweight, and require little or no maintenance, which make them particularly attractive for use in spacecraft. However, because RTGs contain significant quantities of radioactive materials, normally plutonium-238 and its decay products, they must be transported in packages built in accordance with Title 10, Code of Federal Regulations, Part 71 (10 CFR 71). To meet these regulations, a RTG Transportation System (RTGTS) that fully complies with 10 CFR 71 has been developed, which protects RTGs from adverse environmental conditions during normal conditions of transport (e.g., shock, vibration, and heat). To ensure the protection of RTGs from shock and vibration loadings during transport, extensive over-the-road testing was conducted on the RTG`S to obtain real-time recordings of accelerations of the air-ride suspension system trailer floor, packaging, and support structure. This paper provides an overview of the RTG`S, a discussion of the shock and vibration testing, and a comparison of the test results to the specified shock response spectra and power spectral density acceleration criteria.

Becker, D.L.

1997-05-01

136

Mass Properties Testing and Evaluation for the Multi-Mission Radioisotope Thermoelectric Generator  

Microsoft Academic Search

Mass properties (MP) measurements were performed for the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), serial number (S\\/N) 0X730401, the power system designated for the Mars Science Laboratory (MSL) mission. Measurements were made using new mounting fixtures at the mass properties testing station in the Idaho National Laboratory (INL) Space and Security Power Systems Facility (SSPSF). The objective of making mass properties

Felicione; Frank S

2009-01-01

137

New Technology for Microfabrication and Testing of a Thermoelectric Device for Generating Mobile Electrical Power  

NASA Technical Reports Server (NTRS)

We report the results of fabrication and testing of a thermoelectric power generation module. The module was fabricated using a new "flip-chip" module assembly technique that is scalable and modular. This technique results in a low value of contact resistivity ( < or = 10(exp 5) Ohms-sq cm). It can be used to leverage new advances in thin-film and nanostructured materials for the fabrication of new miniature thermoelectric devices. It may also enable monolithic integration of large devices or tandem arrays of devices on flexible or curved surfaces. Under mild testing, a power of 22 mW/sq cm was obtained from small (<100 K) temperature differences. At higher, more realistic temperature differences, approx.500 K, where the efficiency of these materials greatly improves, this power density would scale to between 0.5 and 1 Watt/cm2. These results highlight the excellent potential for the generation and scavenging of electrical power of practical and usable magnitude for remote applications using thermoelectric power generation technologies.

Prasad, Narashimha S.; Taylor, Patrick J.; Trivedi, Sudhir B.; Kutcher, Susan

2010-01-01

138

Influence of thermal environment on optimal working conditions of thermoelectric generators  

NASA Astrophysics Data System (ADS)

Optimization analysis of thermoelectric generators operation is of importance both for practical applications and theoretical considerations. Depending on the desired goal, two different strategies are possible to achieve high performance: through optimization one may seek either power output maximization or conversion efficiency maximization. Recent literature reveals the persistent flawed notion that these two optimal working conditions may be achieved simultaneously. In this article, we lift all source of confusion by correctly posing the problem and solving it. We assume and discuss two possibilities for the environment of the generator to govern its operation: constant incoming heat flux, and constant temperature difference between the heat reservoirs. We demonstrate that, while power and efficiency are maximized simultaneously if the first assumption is considered, this is not possible with the second assumption. This latter corresponds to the seminal analyses of Ioffe who put forth and stressed the importance of the thermoelectric figure of merit ZT. We also provide a simple procedure to determine the different optimal design parameters of a thermoelectric generator connected to heat reservoirs through thermal contacts with a finite and fixed thermal conductance.

Apertet, Y.; Ouerdane, H.; Goupil, C.; Lecoeur, Ph.

2014-10-01

139

Design of a Compact, Portable Test System for Thermoelectric Power Generator Modules  

NASA Astrophysics Data System (ADS)

Measurement of fundamental parameters of a thermoelectric generator (TEG) module, including efficiency, internal electrical resistance, thermal resistance, power output, Seebeck coefficient, and figure of merit ( Z), is necessary in order to design a thermoelectric-based power generation system. This paper presents a new design for a compact, standalone, portable test system that enables measurement of the main parameters of a TEG over a wide range of temperature differences and compression pressures for a 40 mm × 40 mm specimen. The Seebeck coefficient and figure of merit can also be calculated from the information obtained. In the proposed system, the temperature of each side of the TEG can be set at the desired temperature—the hot side as high as 380°C and the cold side as low as 5°C, with 0.5°C accuracy—utilizing an electrical heating system and a thermoelectric-based compact chilling system. Heating and cooling procedures are under control of two proportional-integral-derivative (PID) temperature controllers. Using a monitored pressure mechanism, the TEG specimen is compressed between a pair of hot and cold aluminum cubes, which maintain the temperature difference across the two sides of the TEG. The compressive load can be varied from 0 kPa to 800 kPa. External electrical loading is applied in the form of a direct-current (DC) electronic load. Data collection and processing are through an Agilent 34972A data logger, a computer, and BenchLink software, with results available as computer output. The input power comes from a 240-V general-purpose power point, and the only sound-generating component is a 4-W cooling fan. Total calculated uncertainty in results is approximately 7%. Comparison between experimental data and the manufacturer's published datasheet for a commercially available specimen shows good agreement. These results obtained from a preliminary experimental setup serve as a good guide for the design of a fully automatic portable test system for operational thermoelectric modules.

Faraji, Amir Yadollah; Akbarzadeh, Aliakbar

2013-07-01

140

Unified theory for inhomogeneous thermoelectric generators and coolers including multistage devices.  

PubMed

A novel generalized Lagrange multiplier method for functional optimization with inclusion of subsidiary conditions is presented and applied to the optimization of material distributions in thermoelectric converters. Multistaged devices are considered within the same formalism by inclusion of position-dependent electric current in the legs leading to a modified thermoelectric equation. Previous analytical solutions for maximized efficiencies for generators and coolers obtained by Sherman [J. Appl. Phys. 31, 1 (1960)], Snyder [Phys. Rev. B 86, 045202 (2012)], and Seifert et al. [Phys. Status Solidi A 207, 760 (2010)] by a method of local optimization of reduced efficiencies are recovered by independent proof. The outstanding maximization problems for generated electric power and cooling power can be solved swiftly numerically by solution of a differential equation-system obtained within the new formalism. As far as suitable materials are available, the inhomogeneous TE converters can have increased performance by use of purely temperature-dependent material properties in the thermoelectric legs or by use of purely spatial variation of material properties or by a combination of both. It turns out that the optimization domain is larger for the second kind of device which can, thus, outperform the first kind of device. PMID:23214902

Gerstenmaier, York Christian; Wachutka, Gerhard

2012-11-01

141

Analysis of the inadvertent reentry of the Cassini Spacecraft's Radioisotope Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

A rigorous multi-discipline approach has been developed to compute the aero/thermal/structural response of the Cassini Spacecraft's G_eneral P_urpose H_eat S_ource (GPHS) modules in the unlikely event of accidental reentry of the spacecraft during its Earth gravity-assist maneuver. A new r_eacting, a_blating, c_hemical e_quilibrium/nonequilibrium with r_adiation (RACER) full Navier-Stokes code is applied, along with an in-depth, transient-heating code, a nonlinear structural analysis code, and a six-degree-of-freedom flight-dynamics code. Attention is focused on the GPHS modules that would breakaway from the R_adioisotope T_hermoelectric G_enerators (RTGs) at high altitude. In addition, detailed analyses are performed to determine the survival/failure of the Graphite Impact Shells that would be released if the GPHS fails. The reentry velocity of the GPHS module (20 km/sec) is higher than any previously analyzed Earth reentry trajectory.

Daywitt, James E.; Bhutta, Bilal A.; Vacek, Daniel J.; Letts, William R.; Tobery, E. Wayne

1999-01-01

142

Nanocomposites as thermoelectric materials  

E-print Network

Thermoelectric materials have attractive applications in electric power generation and solid-state cooling. The performance of a thermoelectric device depends on the dimensionless figure of merit (ZT) of the material, ...

Hao, Qing

2010-01-01

143

Development of a solar receiver for a high-efficiency thermionic\\/thermoelectric conversion system  

Microsoft Academic Search

Solar energy is one of the most promising energy resources on Earth and in space, because it is clean and inexhaustible. Therefore, we have been developing a solar-powered high-efficiency thermionic\\/thermoelectric conversion system which combines a thermionic converter (TIC) with a thermoelectric converter (TEC) to use thermal energy efficiently and to achieve high efficiency conversion. The TIC emitter must uniformly heat

H. Naito; Y. Kohsaka; D. Cooke; H. Arashi

1996-01-01

144

Environmental, health and safety assessment of decommissioning radioisotope thermoelectric generators (RTGs) in northwest Russia.  

PubMed

This paper presents findings from public health and environmental assessment work that has been conducted as part of a joint Norwegian-Russian project to decommission radioisotope thermoelectric generators (RTG) in northwest Russia. RTGs utilise heat energy from radioactive isotopes, in this case 90Sr and its daughter nuclide 90Y, to generate electricity as a power source. Different accident scenarios based on the decommissioning process for RTGs are assessed in terms of possible radiation effects to humans and the environment. Doses to humans and biota under the worst-case scenario were lower than threshold limits given in ICRP and IAEA literature. PMID:17768331

Standring, W J F; Dowdall, M; Sneve, M; Selnaes, Ø G; Amundsen, I

2007-09-01

145

Irreversibilities and efficiency at maximum power of heat engines: illustrative case of a thermoelectric generator  

E-print Network

Thermoelectric generators are particularly suitable to investigate the irreversible processes which govern the coupled transport of matter and heat in solid-state systems. We study the efficiency at maximum power in the strong coupling regime, where the thermal flux is proportionnal to the electrical current inside the generator. We demonstrate that depending on the source of irreversibility we obtain either the Curzon-Ahlborn efficiency for external dissipation or a universal efficiency at maximum power for internal dissipation. A continuous change between these two extremes is evidenced. Effects of dissymetry of thermal contact conductance are also investigated.

Apertet, Y; Goupil, C; Lecoeur, Ph

2011-01-01

146

Development of High-efficiency Thermoelectric Materials for Vehicle Waste Heat Utililization  

SciTech Connect

The goals of this . CRADA are: 1) Investigation of atomistic structure and nucleation of nanoprecipitates in (PbTe){sub I-x}(AgSbTe2){sub x} (LAST) system; and 2) Development of non-equilibrium synthesis of thermoelectric materials for waste heat recovery. We have made significant accomplishment in both areas. We studied the structure of LAST materials using high resolution imaging, nanoelectron diffraction, energy dispersive spectrum, arid electron energy loss spectrum, and observed a range of nanoparticles The results, published in J. of Applied Physics, provide quantitative structure information about nanoparticles, that is essential for the understanding of the origin of the high thermoelectric performance in this class of materials. We coordinated non-equilibrium synthesis and characterization of thermoelectric materials for waste heat recovery application. Our results, published in J. of Electronic Materials, show enhanced thermoelectric figure of merit and robust mechanical properties in bulk . filled skutterudites.

Li, Qiang

2009-04-30

147

Techno-Economic Feasibility of Highly Efficient Cost-Effective Thermoelectric-SOFC Hybrid Power Generation Systems  

Microsoft Academic Search

Solid oxide fuel cell (SOFC) systems have the potential to generate exhaust gas streams of high temperature, ranging from 400 to 800 C. These high temperature gas streams can be used for additional power generation with bottoming cycle technologies to achieve higher system power efficiency. One of the potential candidate bottoming cycles is power generation by means of thermoelectric (TE)

Jifeng Zhang; Jean Yamanis

2007-01-01

148

Consideration of Thermoelectric Power Generation by Using Hot Spring Thermal Energy or Industrial Waste Heat  

NASA Astrophysics Data System (ADS)

Today, we face some significant environmental and energy problems such as global warming, urban heat island, and the precarious balance of world oil supply and demand. However, we have not yet found a satisfactory solution to these problems. Waste heat recovery is considered to be one of the best solutions because it can improve energy efficiency by converting heat exhausted from plants and machinery to electric power. This technology would also prevent atmospheric temperature increases caused by waste heat, and decrease fossil fuel consumption by recovering heat energy, thus also reducing CO2 emissions. The system proposed in this research generates electric power by providing waste heat or unharnessed thermal energy to built-in thermoelectric modules that can convert heat into electric power. Waste heat can be recovered from many places, including machinery in industrial plants, piping in electric power plants, waste incineration plants, and so on. Some natural heat sources such as hot springs and solar heat can also be used for this thermoelectric generation system. The generated power is expected to be supplied to auxiliary machinery around the heat source, stored as an emergency power supply, and so on. The attributes of this system are (1) direct power generation using hot springs or waste heat; (2) 24-h stable power generation; (3) stand-alone power system with no noise and no vibration; and (4) easy maintenance attributed to its simple structure with no moving parts. In order to maximize energy use efficiency, the temperature difference between both sides of the thermoelectric (TE) modules built into the system need to be kept as large as possible. This means it is important to reduce thermal resistance between TE modules and heat source. Moreover, the system's efficiency greatly depends on the base temperature of the heat sources and the material of the system's TE modules. Therefore, in order to make this system practical and efficient, it is necessary to choose the heat source first and then design the most appropriate structure for the source by applying analytical methods. This report describes how to design a prototype of a thermoelectric power generator using the analytical approach and the results of performance evaluation tests carried out in the field.

Sasaki, Keiichi; Horikawa, Daisuke; Goto, Koichi

2014-05-01

149

Energy Harvesting Thermoelectric Generators Manufactured Using the Complementary Metal Oxide Semiconductor Process  

PubMed Central

This paper presents the fabrication and characterization of energy harvesting thermoelectric micro generators using the commercial complementary metal oxide semiconductor (CMOS) process. The micro generator consists of 33 thermocouples in series. Thermocouple materials are p-type and n-type polysilicon since they have a large Seebeck coefficient difference. The output power of the micro generator depends on the temperature difference in the hot and cold parts of the thermocouples. In order to increase this temperature difference, the hot part of the thermocouples is suspended to reduce heat-sinking. The micro generator needs a post-CMOS process to release the suspended structures of hot part, which the post-process includes an anisotropic dry etching to etch the sacrificial oxide layer and an isotropic dry etching to remove the silicon substrate. Experiments show that the output power of the micro generator is 9.4 ?W at a temperature difference of 15 K. PMID:23396193

Yang, Ming-Zhi; Wu, Chyan-Chyi; Dai, Ching-Liang; Tsai, Wen-Jung

2013-01-01

150

Optimization Strategies for a Portable Thermoelectric Vaccine Refrigeration System in Developing Communities  

NASA Astrophysics Data System (ADS)

The traditional approach to determine an optimum current for thermoelectric cooling assumes that a refrigeration chamber is insulated and has no thermal resistance to a thermoelectric module. As a result, minimum temperature occurs when Peltier cooling matches with parasitic heat transfer and Joule heating. In practical application, minimum temperature happens when heat addition from the environment is matched with heat extracted by a thermoelectric module, and the optimum current differs from that anticipated by the traditional approach. Hence, consideration for insulation and thermal resistances via thermoelectric module should be made to achieve desirable cooling performance/refrigeration temperature. This paper presents a modeling approach to determine the optimum current as well as the optimum geometry to power a small thermoelectric vaccine delivery system for developing communities under the World Health Organization requirements. The model is derived from three energy conservation equations for temperatures at both ends of the thermoelectric materials within a module, as well as the refrigeration chamber temperature. A prototype was built and demonstrated a minimum temperature of 3.4°C. With optimized module geometry, the system is estimated to reduce power consumption by over 50% while achieving twice the temperature difference.

Ohara, B.; Sitar, R.; Soares, J.; Novisoff, P.; Nunez-Perez, A.; Lee, H.

2014-11-01

151

Influence of an Optimized Thermoelectric Generator on the Back Pressure of the Subsequent Exhaust Gas System of a Vehicle  

NASA Astrophysics Data System (ADS)

Numerous research projects in automotive engineering focus on the industrialization of the thermoelectric generator (TEG). The development and the implementation of thermoelectric systems into the vehicle environment are commonly supported by virtual design activities. In this paper a customized simulation architecture is presented that includes almost all vehicle parts which are influenced by the TEG (overall system simulation) but is nevertheless capable of real-time use. Moreover, an optimized planar TEG with minimum nominal power output of about 580 W and pressure loss at nominal conditions of 10 mbar, synthesized using the overall system simulation, and the overall system simulation itself are used to answer a generally neglected question: What influence does the position of a TEG have on the back pressure of the subsequent exhaust gas system of the vehicle? It is found that the influence of the TEG on the muffler is low, but the catalytic converter is strongly influenced. It is shown that the TEG can reduce the back pressure of an exhaust gas system so much that its overall back pressure is less than the back pressure of a standard exhaust gas system.

Kühn, Roland; Koeppen, Olaf; Kitte, Jens

2014-06-01

152

Transport and handling of radioisotope thermoelectric generators at Westinghouse Hanford Company  

NASA Astrophysics Data System (ADS)

Westinghouse Hnaford Company is converting part of the Fuels and Materials Examination Facility, located at the Hanford Site in southeastern Washington State, to fuel and test radioisotope thermoelectric generators. The facility is referred to as the Radioisotope Power Systems Facility (RPSF). Historically, this activity has been performed at EG&G Mound Applied Technologies Inc. in Miamisburg, Ohio. Transportation and handling of the generator within the RPSF will be facilitated by the re-design of the Mound system to reduce the number of steps and therefore reduce operator dose. The overall handling concept has been retained and, wherever possible, the original design has been maintained. Changes reflect a simplified design, reducing the number of parts and a consistent interface between the generator to both the testing equipment and the transport cart. The new system design also improves operator efficiency and reduces operating costs.

Alderman, Carol J.

1992-01-01

153

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

SciTech Connect

A conceptual design for a demonstration 500-watt(e) radioisotopic thermoelectric generator has been created for the Department of Energy. The design effort was divided into two tasks, viz., create a design specification for a capsule strength member that utilizes a standard Strontium-90 fluoride-filled WESF inner liner, and create a conceptual design for a 500-watt(e) RTG. Both tasks have been accomplished. 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 can, if desired, be 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 has been met or exceeded. The power source will generate the required power for the required service period at 28 volts dc with a conversion efficiency of 8%, provided the existing in-pool capsules at WESF meet the assumed thermal-inventory requirements.

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

1983-04-01

154

Device for use in a furnace exhaust stream for thermoelectric generation  

DOEpatents

A device for generating voltage or electrical current includes an inner elongated member mounted in an outer elongated member, and a plurality of thermoelectric modules mounted in the space between the inner and the outer members. The outer and/or inner elongated members each include a plurality of passages to move a temperature altering medium through the members so that the device can be used in high temperature environments, e.g. the exhaust system of an oxygen fired glass melting furnace. The modules are designed to include a biasing member and/or other arrangements to compensate for differences in thermal expansion between the first and the second members. In this manner, the modules remain in contact with the first and second members. The voltage generated by the modules can be used to power electrical loads.

Polcyn, Adam D.

2013-06-11

155

Thermoelectric Generators 1. Thermoelectric generator  

E-print Network

) p n p n n p p p n Positive (+) Negative (-) Heat Absorbed Heat Rejected Electrical Conductor (copper. In 1834, Jean Peltier discovered the reverse process that the passage of an electric current through two points of a current-carrying conductor, heat is either absorbed or liberated depending

Lee, Ho Sung

156

Highly Efficient Multilayer Thermoelectric Devices  

NASA Technical Reports Server (NTRS)

Multilayer thermoelectric devices now at the prototype stage of development exhibit a combination of desirable characteristics, including high figures of merit and high performance/cost ratios. These devices are capable of producing temperature differences of the order of 50 K in operation at or near room temperature. A solvent-free batch process for mass production of these state-of-the-art thermoelectric devices has also been developed. Like prior thermoelectric devices, the present ones have commercial potential mainly by virtue of their utility as means of controlled cooling (and/or, in some cases, heating) of sensors, integrated circuits, and temperature-critical components of scientific instruments. The advantages of thermoelectric devices for such uses include no need for circulating working fluids through or within the devices, generation of little if any noise, and high reliability. The disadvantages of prior thermoelectric devices include high power consumption and relatively low coefficients of performance. The present development program was undertaken in the hope of reducing the magnitudes of the aforementioned disadvantages and, especially, obtaining higher figures of merit for operation at and near room temperature. Accomplishments of the program thus far include development of an algorithm to estimate the heat extracted by, and the maximum temperature drop produced by, a thermoelectric device; solution of the problem of exchange of heat between a thermoelectric cooler and a water-cooled copper block; retrofitting of a vacuum chamber for depositing materials by sputtering; design of masks; and fabrication of multilayer thermoelectric devices of two different designs, denoted I and II. For both the I and II designs, the thicknesses of layers are of the order of nanometers. In devices of design I, nonconsecutive semiconductor layers are electrically connected in series. Devices of design II contain superlattices comprising alternating electron-acceptor (p)-doped and electron-donor (n)-doped, nanometer- thick semiconductor layers.

Boufelfel, Ali

2006-01-01

157

Thermoelectric Devices: Solid-State Refrigerators and Electrical Generators in the Classroom  

NASA Astrophysics Data System (ADS)

Thermoelectric devices are solid-state devices that convert thermal energy from a temperature gradient into electrical energy (the Seebeck effect) or convert electrical energy into a temperature gradient (the Peltier effect). The first application is used most notably in spacecraft power generation systems (for example, in Voyager I and II) and in thermocouples for temperature measurement, while the second application is largely used in specialized cooling applications. Both applications can be demonstrated in the lecture hall to illustrate thermodynamic principles in a compelling manner. They also provide insight into the workings of a high-tech system that is achieving more widespread consumer use. The most visible consumer use of thermoelectric devices utilizing the Peltier effect is in portable electric food coolers/warmers that plug into an automobile cigarette lighter. Conventional cooling systems such as those used in refrigerators utilize a compressor and a working fluid to transfer heat. Thermal energy is absorbed and released as the working fluid undergoes expansion and compression and changes phase from liquid to vapor and back, respectively (1). Semiconductor thermoelectric coolers (also known as Peltier coolers) offer several advantages over conventional systems. They are entirely solid-state devices, with no moving parts; this makes them rugged, reliable, and quiet. They use no ozone-depleting chlorofluorocarbons, potentially offering a more environmentally responsible alternative to conventional refrigeration. They can be extremely compact, much more so than compressor-based systems. Precise temperature control (< ±0.1 °C) can be achieved with Peltier coolers. However, their efficiency is low compared to conventional refrigerators. Thus, they are used in niche applications where their unique advantages outweigh their low efficiency. Although some large-scale applications have been considered (on submarines and surface vessels), Peltier coolers are generally used in applications where small size is needed and the cooling demands are not too great, such as for cooling electronic components. Apparatus Acquiring and Preparing a Thermoelectric Module A thermoelectric cooling module can be obtained by purchasing and disassembling a portable food cooler, (e.g., Coleman or Igloo brands). These are available at many department stores. If several model sizes are available, buy the least expensive: all contain thermoelectric modules that are suitable for demonstration purposes. Portable food coolers can be bought for less than 90. These will probably include the cooler and a power cord, fitted with a cigarette lighter adapter for 12-V automotive use. For classroom demonstrations a power supply will be needed; these can usually be purchased at the same place as the portable food cooler for about 30. Disassembling an Igloo KoolMate series Kool Rider 6-quart Thermoelectric Roadster reveals that the cooling system is entirely contained in the cooler lid. A number of screws have to be removed to access the thermoelectric module. The module comes equipped with finned aluminum heat sinks attached to both sides; one of these has to be detached in order to remove the module from the lid. The heat sink is then reattached to the module, as shown in Figure 1. Figure 1. Thermoelectric module with attached heat sinks, from a disassembled portable food cooler. The smaller heat sink provides cooling to the cooler's interior in normal operation. A small fan is used to circulate air over the heat sinks. Note that the module itself is very small compared to the attached hardware. The module itself is approximately 3 cm by 3 cm and a few millimeters thick. Electrical connections for the module are simply a red and a black wire. The lid also contains a small fan used to circulate air over the heat sinks for more efficient heat transfer. This module runs on 12 volts dc and draws from 3.0 to 4.2 amps. Power can be provided from a car battery or from a suitable ac-to-dc converter, such as the Igloo KoolMate ac/dc converter. The conver

Winder, Edmund J.; Ellis, Arthur B.; Lisensky, George C.

1996-10-01

158

Solution to the 1-D unsteady heat conduction equation with internal Joule heat generation for thermoelectric devices  

Microsoft Academic Search

Thermoelectric devices are semiconductor devices which are capable of either generating a voltage when placed in between a temperature gradient, exploiting the Seebeck effect, or producing a temperature gradient when powered by electricity, exploiting the Peltier effect. The devices are usually employed in environments with time-varying temperature differences and input\\/output powers. Therefore it becomes important to understand the behaviour of

A. Montecucco; J. R. Buckle; A. R. Knox

159

On the Use of Thermoelectric (TE) Applications Based on Commercial Modules: The Case of TE Generator and TE Cooler  

NASA Astrophysics Data System (ADS)

In recent years, thermoelectricity sees rapidly increasing usages in applications like portable refrigerators, beverage coolers, electronic component coolers etc. when used as Thermoelectric Cooler (TEC), and Thermoelectric Generators (TEG) which make use of the Seebeck effect in semiconductors for the direct conversion of heat into electrical energy and is of particular interest for systems of highest reliability or for waste heat recovery. In this work, we examine the performance of commercially available TEC and TEG. A prototype TEC-refrigerator has been designed, modeled and constructed for in-car applications. Additionally, a TEG was made, in order to measure the gained power and efficiency. Furthermore, a TEG module was tested on a small size car (Toyota Starlet, 1300 cc), in order to measure the gained power and efficiency for various engine loads. With the use of a modeling approach, we evaluated the thermal contact resistances and their influence on the final device efficiency.

Zorbas, K.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Kyratsi, Th.

2010-01-01

160

Semiconducting large bandgap oxides as potential thermoelectric materials for high-temperature power generation?  

NASA Astrophysics Data System (ADS)

Semiconducting large bandgap oxides are considered as interesting candidates for high-temperature thermoelectric power generation (700-1,200 °C) due to their stability, lack of toxicity and low cost, but so far they have not reached sufficient performance for extended application. In this review, we summarize recent progress on thermoelectric oxides, analyze concepts for tuning semiconductor thermoelectric properties with view of their applicability to oxides and determine key drivers and limitations for electrical and thermal transport properties in oxides based on our own experimental work and literature results. For our experimental assessment, we have selected representative multicomponent oxides that range from materials with highly symmetric crystal structure (SrTiO3 perovskite) over oxides with large densities of planar crystallographic defects (Ti n O2 n-1 Magnéli phases with a single type of shear plane, NbO x block structures with intersecting shear planes and WO3- x with more defective block and channel structures) to layered superstructures (Ca3Co4O9 and double perovskites) and also include a wide range of their composites with a variety of second phases. Crystallographic or microstructural features of these oxides are in 0.3-2 nm size range, so that oxide phonons can efficiently interact with them. We explore in our experiments the effects of doping, grain size, crystallographic defects, superstructures, second phases, texturing and (to a limited extend) processing on electric conductivity, Seebeck coefficient, thermal conductivity and figure of merit. Jonker and lattice-versus-electrical conductivity plots are used to compare specific materials and material families and extract levers for future improvement of oxide thermoelectrics. We show in our work that oxygen vacancy doping (reduction) is a more powerful driver for improving the power factor for SrTiO3, TiO2 and NbO x than heterovalent doping. Based on our Seebeck-conductivity plots, we derived a set of highest achievable power factors. We met these best values in our own experiments for our titanium oxide- and niobium oxide-based materials. For strontium titanate-based materials, the estimated highest power factor was not reached; further material improvement is possible and can be reached for materials with higher carrier densities. Our results show that periodic crystallographic defects and superstructures are most efficient in reducing the lattice thermal conductivity in oxides, followed by hetero- and homovalent doping. Due to the small phonon mean free path in oxides, grain boundary scattering in nanoceramics or materials with nanodispersions is much less efficient. We investigated the impact of texturing in Ca3Co4O9 ceramics on thermoelectric performance; we did not find any improvement in the overall in-plane performance of a textured ceramic compared to the corresponding random ceramic.

Backhaus-Ricoult, M.; Rustad, J.; Moore, L.; Smith, C.; Brown, J.

2014-08-01

161

Development and Evolution of Nanostructure in Bulk Thermoelectric Pb-Te-Sb Alloys  

E-print Network

Development and Evolution of Nanostructure in Bulk Thermoelectric Pb-Te-Sb Alloys TERUYUKI IKEDA,1 been conventional, simple semicon- ductors. Examples include bismuth telluride alloys, lead telluride at several temperatures to examine the time evolution of fraction transformed and inter- lamellar spacing

162

Waste Heat Recovery from a Marine Waste Incinerator Using a Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

A marine waste incinerator has been evaluated for waste heat harvesting using thermoelectric generators (TEG). The application has been evaluated using mathematical modeling to optimize the heat exchanger and some vital design parameters of the TEG. The calculation shows that it is possible to extract 58 kWel at a price of 6.6 US/W from an 850-kWth incinerator when optimizing for maximum power. However, minimizing the cost, it is possible to get 25 kWel at a price of 2.5 US/W. A trade-off between the two targets leads to a combination that gives 38 kWel at a price of 2.7 US/W.

Kristiansen, N. R.; Snyder, G. J.; Nielsen, H. K.; Rosendahl, L.

2012-06-01

163

Method of controlling temperature of a thermoelectric generator in an exhaust system  

SciTech Connect

A method of controlling the temperature of a thermoelectric generator (TEG) in an exhaust system of an engine is provided. The method includes determining the temperature of the heated side of the TEG, determining exhaust gas flow rate through the TEG, and determining the exhaust gas temperature through the TEG. A rate of change in temperature of the heated side of the TEG is predicted based on the determined temperature, the determined exhaust gas flow rate, and the determined exhaust gas temperature through the TEG. Using the predicted rate of change of temperature of the heated side, exhaust gas flow rate through the TEG is calculated that will result in a maximum temperature of the heated side of the TEG less than a predetermined critical temperature given the predicted rate of change in temperature of the heated side of the TEG. A corresponding apparatus is provided.

Prior, Gregory P; Reynolds, Michael G; Cowgill, Joshua D

2013-05-21

164

Quality Assurance Plan for Heat Source/Radioisotope Thermoelectric Generator Programs  

SciTech Connect

The purpose of this document is to serve as the Quality Assurance Plan for Heat Source/Radioisotope Thermoelectric Generator (HS/RTG) programs performed at EG&G Mound Applied Technologies. As such, it identifies and describes the systems and activities in place to support the requirements contained in DOE Order 5700.6C as reflected in MD-10334, Mound Quality Policy and Responsibilities and the DOE/RPSD supplement, OSA/PQAR-1, Programmatic Quality Assurance Requirements for Space and Terrestrial Nuclear Power Systems. Unique program requirements, including additions, modifications, and exceptions to these quality requirements, are contained in the appendices of this plan. Additional appendices will be added as new programs and activities are added to Mound's HS/RTG mission assignment.

Gabriel, D. M.; Miller, G. D.; Bohne, W. A.

1995-03-16

165

Mo(3)Sb(7-x)Te(x) for Thermoelectric Power Generation  

NASA Technical Reports Server (NTRS)

Compounds having compositions of Mo(3)Sb(7-x)Te(x) (where x = 1.5 or 1.6) have been investigated as candidate thermoelectric materials. These compounds are members of a class of semiconductors that includes previously known thermoelectric materials. All of these compounds have complex crystalline and electronic structures. Through selection of chemical compositions and processing conditions, it may be possible to alter the structures to enhance or optimize thermoelectric properties.

Snyder, G. Jeffrey; Gascoin, Frank S.; Rasmussen, Julia

2009-01-01

166

Nanowire Thermoelectric Devices  

NASA Technical Reports Server (NTRS)

Nanowire thermoelectric devices, now under development, are intended to take miniaturization a step beyond the prior state of the art to exploit the potential advantages afforded by shrinking some device features to approximately molecular dimensions (of the order of 10 nm). The development of nanowire-based thermoelectric devices could lead to novel power-generating, cooling, and sensing devices that operate at relatively low currents and high voltages. Recent work on the theory of thermoelectric devices has led to the expectation that the performance of such a device could be enhanced if the diameter of the wires could be reduced to a point where quantum confinement effects increase charge-carrier mobility (thereby increasing the Seebeck coefficient) and reduce thermal conductivity. In addition, even in the absence of these effects, the large aspect ratios (length of the order of tens of microns diameter of the order of tens of nanometers) of nanowires would be conducive to the maintenance of large temperature differences at small heat fluxes. The predicted net effect of reducing diameters to the order of tens of nanometers would be to increase its efficiency by a factor of .3. Nanowires made of thermoelectric materials and devices that comprise arrays of such nanowires can be fabricated by electrochemical growth of the thermoelectric materials in templates that contain suitably dimensioned pores (10 to 100 nm in diameter and 1 to 100 microns long). The nanowires can then be contacted in bundles to form devices that look similar to conventional thermoelectric devices, except that a production version may contain nearly a billion elements (wires) per square centimeter, instead of fewer than a hundred as in a conventional bulk thermoelectric device or fewer than 100,000 as in a microdevice. It is not yet possible to form contacts with individual nanowires. Therefore, in fabricating a nanowire thermoelectric device, one forms contacts on nanowires in bundles of the order of 10-microns wide. The fill factor for the cross-section of a typical bundle is about 1/2. Nanowires have been grown in alumina templates with pore diameters of 100 and 40 nm.

Borshchevsky, Alexander; Fleurial, Jean-Pierre; Herman, Jennifer; Ryan, Margaret

2005-01-01

167

Multi-Mission Radioisotope Thermoelectric Generator Heat Exchangers for the Mars Science Laboratory Rover  

NASA Technical Reports Server (NTRS)

The addition of the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) to the Mars Science Laboratory (MSL) Rover requires an advanced thermal control system that is able to both recover and reject the waste heat from the MMRTG as needed in order to maintain the onboard electronics at benign temperatures despite the extreme and widely varying environmental conditions experienced both on the way to Mars and on the Martian surface. Based on the previously successful Mars landed mission thermal control schemes, a mechanically pumped fluid loop (MPFL) architecture was selected as the most robust and efficient means for meeting the MSL thermal requirements. The MSL heat recovery and rejection system (HRS) is comprised of two Freon (CFC-11) MPFLs that interact closely with one another to provide comprehensive thermal management throughout all mission phases. The first loop, called the Rover HRS (RHRS), consists of a set of pumps, thermal control valves, and heat exchangers (HXs) that enables the transport of heat from the MMRTG to the rover electronics during cold conditions or from the electronics straight to the environment for immediate heat rejection during warm conditions. The second loop, called the Cruise HRS (CHRS), is thermally coupled to the RHRS during the cruise to Mars, and provides a means for dissipating the waste heat more directly from the MMRTG as well as from both the cruise stage and rover avionics by promoting circulation to the cruise stage radiators. A multifunctional structure was developed that is capable of both collecting waste heat from the MMRTG and rejecting the waste heat to the surrounding environment. It consists of a pair of honeycomb core sandwich panels with HRS tubes bonded to both sides. Two similar HX assemblies were designed to surround the MMRTG on the aft end of the rover. Heat acquisition is accomplished on the interior (MMRTG facing) surface of each HX while heat rejection is accomplished on the exterior surface of each HX. Since these two surfaces need to be at very different temperatures in order for the fluid loops to perform efficiently, they need to be thermally isolated from one another. The HXs were therefore designed for high in-plane thermal conductivity and extremely low through-thickness thermal conductivity by using aluminum facesheets and aerogel as insulation inside a composite honeycomb core. Complex assemblies of hand-welded and uniquely bent aluminum tubes are bonded onto each side of the HX panels, and are specifically designed to be easily mated and demated to the rest of the RHRS in order to ease the integration effort.

Mastropietro, A. J.; Beatty, John S.; Kelly, Frank P.; Bhandari, Pradeep; Bame, David P.; Liu, Yuanming; Birux, Gajanana C.; Miller, Jennifer R.; Pauken, Michael T.; Illsley, Peter M.

2012-01-01

168

Long term thermoelectric module testing system  

NASA Astrophysics Data System (ADS)

Thermoelectric generators can be used for converting waste heat into electric power. Significant interest in developing new materials in recent years has led to the discovery of several promising thermoelectrics, however, there can be considerable challenges in developing the materials into working devices. Testing and feedback is needed at each step to gain valuable information for identification of difficulties, quality of the materials and modules, repeatability in fabrication, and longevity of the devices. This paper describes a long-term module testing system for monitoring the output power of a module over extended testing times. To evaluate the system, we have tested commercially available thermoelectric modules over a one month time period.

D'Angelo, Jonathan; Hogan, Timothy

2009-10-01

169

PUBLISHED ONLINE: 1 MAY 2011 | DOI: 10.1038/NMAT3013 High-performance flat-panel solar thermoelectric  

E-print Network

thermoelectric generators with high thermal concentration Daniel Kraemer1 , Bed Poudel2 , Hsien-Ping Feng1 , J and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar

Huang, Jianyu

170

Comparison power generation by using thermoelectric modules between cooling module and power module for low temperature application  

Microsoft Academic Search

The paper presents comparison thermoelectric power generation between cooling and power modules. In order to investigate which type of TE module is suitable for the power generation at low temperature of hot side of TE, four TE modules were considered: two TE cooling modules (TE model TEC1-12708 and MT2-1.-127) and two TE power modules (TE model TEP1-1264-3.4 and TEG1-1260-5.1) for

S. Maneewan; B. Zeghmati

2007-01-01

171

The potential impacts of climate-change policy on freshwater use in thermoelectric power generation  

E-print Network

a price on carbon would change the mix of power plants and the amount of water they withdraw and consume System and water-use factors for thermoelectric power plants derived from electric utility data compiled The greatest use of water withdrawals in the United States is for thermoelectric power plants. The U

Jackson, Robert B.

172

A miniaturized mW thermoelectric generator for nw objectives: continuous, autonomous, reliable power for decades.  

SciTech Connect

We have built and tested a miniaturized, thermoelectric power source that can provide in excess of 450 {micro}W of power in a system size of 4.3cc, for a power density of 107 {micro}W/cc, which is denser than any system of this size previously reported. The system operates on 150mW of thermal input, which for this system was simulated with a resistive heater, but in application would be provided by a 0.4g source of {sup 238}Pu located at the center of the device. Output power from this device, while optimized for efficiency, was not optimized for form of the power output, and so the maximum power was delivered at only 41mV. An upconverter to 2.7V was developed concurrently with the power source to bring the voltage up to a usable level for microelectronics.

Aselage, Terrence Lee; Siegal, Michael P.; Whalen, Scott; Frederick, Scott K.; Apblett, Christopher Alan; Moorman, Matthew Wallace

2006-10-01

173

Near-term thermoelectric nuclear power options for SEI missions  

NASA Technical Reports Server (NTRS)

Three different types of thermoelectric nuclear space power systems are discussed. First, the general purpose heat source Radioisotope Thermoelectric Generator (RTG), which was qualified and flown on Galileo/Ulysses and is in development for Cassini, is discussed. Second, the modular RTG, which is undergoing life verification, is discussed. Finally, the SP-100 is discussed. The information is presented in viewgraph form.

Peterson, Jerry R.

1992-01-01

174

Near-term thermoelectric nuclear power options for SEI missions  

NASA Astrophysics Data System (ADS)

Three different types of thermoelectric nuclear space power systems are discussed. First, the general purpose heat source Radioisotope Thermoelectric Generator (RTG), which was qualified and flown on Galileo/Ulysses and is in development for Cassini, is discussed. Second, the modular RTG, which is undergoing life verification, is discussed. Finally, the SP-100 is discussed. The information is presented in viewgraph form.

Peterson, Jerry R.

175

Fabrication of High-Temperature-Stable Thermoelectric Generator Modules Based on Nanocrystalline Silicon  

NASA Astrophysics Data System (ADS)

High-temperature-stable thermoelectric generator modules (TGMs) based on nanocrystalline silicon have been fabricated, characterized by the Harman technique, and measured in a generator test facility at the German Aerospace Center. Starting with highly doped p- and n-type silicon nanoparticles from a scalable gas-phase process, nanocrystalline bulk silicon was obtained using a current-activated sintering technique. Electrochemical plating methods were employed to metalize the nanocrystalline silicon. The specific electrical contact resistance ? c of the semiconductor-metal interface was characterized by a transfer length method. Values as low as ? c < 1 × 10-6 ? cm2 were measured. The device figure of merit of a TGM with 64 legs was approximately ZT = 0.13 at 600°C as measured by the Harman technique. Using a generator test facility, the maximum electrical power output of a TGM with 100 legs was measured to be roughly 1 W at hot-side temperature of 600°C and cold-side temperature of 300°C.

Kessler, V.; Dehnen, M.; Chavez, R.; Engenhorst, M.; Stoetzel, J.; Petermann, N.; Hesse, K.; Huelser, T.; Spree, M.; Stiewe, C.; Ziolkowski, P.; Schierning, G.; Schmechel, R.

2014-05-01

176

Techno-Economic Feasibility of Highly Efficient Cost-Effective Thermoelectric-SOFC Hybrid Power Generation Systems  

SciTech Connect

Solid oxide fuel cell (SOFC) systems have the potential to generate exhaust gas streams of high temperature, ranging from 400 to 800 C. These high temperature gas streams can be used for additional power generation with bottoming cycle technologies to achieve higher system power efficiency. One of the potential candidate bottoming cycles is power generation by means of thermoelectric (TE) devices, which have the inherent advantages of low noise, low maintenance and long life. This study was to analyze the feasibility of combining coal gas based SOFC and TE through system performance and cost techno-economic modeling in the context of multi-MW power plants, with 200 kW SOFC-TE module as building blocks. System and component concepts were generated for combining SOFC and TE covering electro-thermo-chemical system integration, power conditioning system (PCS) and component designs. SOFC cost and performance models previously developed at United Technologies Research Center were modified and used in overall system analysis. The TE model was validated and provided by BSST. The optimum system in terms of energy conversion efficiency was found to be a pressurized SOFC-TE, with system efficiency of 65.3% and cost of $390/kW of manufacturing cost. The pressurization ratio was approximately 4 and the assumed ZT of the TE was 2.5. System and component specifications were generated based on the modeling study. The major technology and cost barriers for maturing the system include pressurized SOFC stack using coal gas, the high temperature recycle blowers, and system control design. Finally, a 4-step development roadmap is proposed for future technology development, the first step being a 1 kW proof-of-concept demonstration unit.

Jifeng Zhang; Jean Yamanis

2007-09-30

177

Thermoelectric power generator module of 1616 Bi2Te3 and 0.6% ErAs:,,InGaAs...1-x,,InAlAs...x segmented elements  

E-print Network

Thermoelectric power generator module of 16Ã?16 Bi2Te3 and 0.6% ErAs:,,InGaAs...1-x; published online 26 August 2009 We report the fabrication and characterization of thermoelectric power temperature was at 610 K. The thermoelectric properties of InGaAs 1-x InAlAs x were characterized from 300 up

Bowers, John

178

Measurements and Standards for Thermoelectric Materials  

E-print Network

Measurements and Standards for Thermoelectric Materials CERAMICS Our goal is to develop standard, electrical conductivity, thermal conductivity) for thin film and bulk thermoelectric materials to enable approach will facilitate comparison of thermoelectric data between leading laboratories, and accelerate

179

High-Temperature Performance of Stacked Silicon Nanowires for Thermoelectric Power Generation  

NASA Astrophysics Data System (ADS)

Deep reactive-ion etching at cryogenic temperatures (cryo-DRIE) has been used to produce arrays of silicon nanowires (NWs) for thermoelectric (TE) power generation devices. Using cryo-DRIE, we were able to fabricate NWs of large aspect ratios (up to 32) using a photoresist mask. Roughening of the NW sidewalls occurred, which has been recognized as beneficial for low thermal conductivity. Generated NWs, which were 7 ?m in length and 220 nm to 270 nm in diameter, were robust enough to be stacked with a bulk silicon chip as a common top contact to the NWs. Mechanical support of the NW array, which can be created by filling the free space between the NWs using silicon oxide or polyimide, was not required. The Seebeck voltage, measured across multiple stacks of up to 16 bulk silicon dies, revealed negligible thermal interface resistance. With stacked silicon NWs, we observed Seebeck voltages that were an order of magnitude higher than those observed for bulk silicon. Degradation of the TE performance of silicon NWs was not observed for temperatures up to 470°C and temperature gradients up to 170 K.

Stranz, Andrej; Waag, Andreas; Peiner, Erwin

2013-07-01

180

Top-Down Silicon Nanowire-Based Thermoelectric Generator: Design and Characterization  

NASA Astrophysics Data System (ADS)

A silicon nanowire (SiNW) array-based thermoelectric generator (TEG) was assembled and characterized. The SiNW array had pitch of 400 nm, and SiNW diameter and height of <100 nm and ~1 ?m, respectively. The SiNW array was formed using a top-down approach: deep-ultraviolet (UV) lithography and dry reactive-ion etching. Specific groups of SiNWs were doped n- and p-type using ion implantation, and air gaps between the SiNWs were filled with silicon dioxide (SiO2). The bottom and top electrodes were formed using a nickel silicidation process and aluminum metallization, respectively. Temperature difference across the TEG was generated with a heater and a commercial Peltier cooler. A maximum open-circuit voltage of 2.7 mV was measured for a temperature difference of 95 K across the whole experimental setup, corresponding to power output of 4.6 nW. For further improvement, we proposed the use of polyimide as a filler material to replace SiO2. Polyimide, with a rated thermal conductivity value one order of magnitude lower than that of SiO2, resulted in a larger measured thermal resistance when used as a filler material in a SiNW array. This advantage may be instrumental in future performance improvement of SiNW TEGs.

Li, Y.; Buddharaju, K.; Singh, N.; Lee, S. J.

2012-06-01

181

PDMS/Kapton interface plasma treatment effects on the polymeric package for a wearable thermoelectric generator.  

PubMed

The present work highlights the progress in the field of polymeric package reliability engineering for a flexible thermoelectric generator realized by thin-film technology on a Kapton substrate. The effects of different plasma treatments on the mechanical performance at the interface of a poly(dimethylsiloxane) (PDMS)/Kapton assembly were investigated. To increase the package mechanical stability of the realized wearable power source, the Kapton surface wettability after plasma exposure was investigated by static contact-angle measurements using deionized water and PDMS as test liquids. In fact, the well-known weak adhesion between PDMS and Kapton can lead to a delamination of the package with an unrecoverable damage of the generator. The plasma effect on the adhesion performances was evaluated by the scratch-test method. The best result was obtained by performing a nitrogen plasma treatment at a radio-frequency power of 20 W and a gas flow of 20 sccm, with a measured critical load of 1.45 N, which is 2.6 times greater than the value measured on an untreated Kapton substrate and 1.9 times greater than the one measured using a commercial primer. PMID:23829424

Francioso, Luca; De Pascali, Chiara; Bartali, Ruben; Morganti, Elisa; Lorenzelli, Leandro; Siciliano, Pietro; Laidani, Nadhira

2013-07-24

182

Aggregated modeling and control of a boost-buck cascade converter for maximum power point tracking of a thermoelectric generator  

Microsoft Academic Search

For a wide output voltage ranged thermoelectric generator, it is necessary to have a DC-DC converter that allows voltage boost and buck functions. In this paper, a boost-buck cascade DC-DC converter is adopted to allow input voltage range from near 0 V to 25 V and output voltage range from 12.3 V to 16.5 V, needed for vehicle battery charging.

Rae-Young Kim; Jih-Sheng Lai

2008-01-01

183

Thermoelectric generation of charge imbalance at a superconductor-normal metal interface  

Microsoft Academic Search

The thermoelectric voltage produced across a superconductor--normal--metal--superconductor (SNS) sandwich by an applied heat current has been measured in Pb--Cu--PbBi and In--Al--Sn as a function of temperature. The observed divergence of the thermoelectric voltage near T\\/sub c\\/ is attributed to a charge imbalance region decaying into the superconductor from the NS interface over the quasiparticle diffusion length lambda\\/sub Q\\/ +- .

Van Harlingen

1981-01-01

184

Thermoelectric generation of charge imbalance at a superconductor-normal metal interface  

Microsoft Academic Search

The thermoelectric voltage produced across a superconductor-normal metal-superconductor (SNS) sandwich by an applied heat current has been measured in Pb-Cu-PbBi and In-Al-Sn as a function of temperature. The observed divergence of the thermoelectric voltage near Tc is attributed to a charge imbalance region decaying into the superconductor from the NS interface over the quasiparticle diffusion length ?Q*. The charge imbalance

D. J. Harlingen

1981-01-01

185

Electron-beam processing of kilogram quantities of iridium for radioisotope thermoelectric generator applications  

SciTech Connect

Iridium alloys are used as fuel-cladding materials in radioisotope thermoelectric generators (RTGs). Hardware produced at the Oak Ridge National Laboratory (ORNL) has been used in Voyagers I and 2, Galilee, and Ulysses spacecraft. An integral part of the production of iridium-sheet metal involves electron-beam (EB) processing. These processes include the degassing of powder-pressed compacts followed by multiple meltings in order to purify 500-g buttons of Ir-0.3% W alloy. Starting in 1972 and continuing into 1992, our laboratory EB processing was Performed (ca. 1970) in a 60-kW (20 kV at 3 A), two-gun system. In 1991, a new 150-kW EB gun facility was installed to complement the older unit. This paper describes how the newly installed system was qualified for production of RTG developmental work is discussed that will potentially improve the existing process by utilizing the capabilities of the new EB system.

Huxford, T.J.; Ohriner, E.K.

1992-01-01

186

Electron-beam processing of kilogram quantities of iridium for radioisotope thermoelectric generator applications  

SciTech Connect

Iridium alloys are used as fuel-cladding materials in radioisotope thermoelectric generators (RTGs). Hardware produced at the Oak Ridge National Laboratory (ORNL) has been used in Voyagers I and 2, Galilee, and Ulysses spacecraft. An integral part of the production of iridium-sheet metal involves electron-beam (EB) processing. These processes include the degassing of powder-pressed compacts followed by multiple meltings in order to purify 500-g buttons of Ir-0.3% W alloy. Starting in 1972 and continuing into 1992, our laboratory EB processing was Performed (ca. 1970) in a 60-kW (20 kV at 3 A), two-gun system. In 1991, a new 150-kW EB gun facility was installed to complement the older unit. This paper describes how the newly installed system was qualified for production of RTG developmental work is discussed that will potentially improve the existing process by utilizing the capabilities of the new EB system.

Huxford, T.J.; Ohriner, E.K.

1992-12-31

187

Thermoelectric generator testing and RTG degradation mechanisms evaluation. Progress report No. 36  

SciTech Connect

The n-type selenide legs after 15,000 hours continue to show reasonable agreement with the 3M Co. published thermal conductivity data. In the ingradient testing after 16,500 hours the 3 surviving n-legs (out of 5) show serious degradation in power to load. Weight loss and thermoelectricity property measurements on the first samples of material produced by G.E. continue to correspond to the results previously obtained on R.C.A. material from the MHW program. The remaining MHW generator on test, Q1-A, has accumulated 23,679 hours and performance remains stable. The 18 couple modules S/N-1 and -3 previously tested at RCA show no significant change in operation during the current JPL testing. A comparison of LES 8/9 RTG's with an improved version of DEGRA is shown. No changes in the trends of degradation of LES 8 and 9 and the Voyager RTGs have been observed.

Lockwood, A.; Shields, V.

1980-07-01

188

POTENTIAL THERMOELECTRIC APPLICATIONS IN DIESEL VEHICLES  

SciTech Connect

Novel thermodynamic cycles developed by BSST provide improvements by factors of approximately 2 in cooling, heating and power generation efficiency of solid-state thermoelectric systems. The currently available BSST technology is being evaluated in automotive development programs for important new applications. Thermoelectric materials are likely to become available that further increase performance by a comparable factor. These major advancements should allow the use of thermoelectric systems in new applications that have the prospect of contributing to emissions reduction, fuel economy, and improved user comfort. Potential applications of thermoelectrics in diesel vehicles are identified and discussed. As a case in point, the history and status of the Climate Controlled Seat (CCS) system from Amerigon, the parent of BSST, is presented. CCS is the most successful and highest production volume thermoelectric system in vehicles today. As a second example, the results of recent analyses on electric power generation from vehicle waste heat are discussed. Conclusions are drawn as to the practicality of waste power generation systems that incorporate BSST's thermodynamic cycle and advanced thermoelectric materials.

Crane, D

2003-08-24

189

Research on a power management system for thermoelectric generators to drive wireless sensors on a spindle unit.  

PubMed

Thermoelectric energy harvesting is emerging as a promising alternative energy source to drive wireless sensors in mechanical systems. Typically, the waste heat from spindle units in machine tools creates potential for thermoelectric generation. However, the problem of low and fluctuant ambient temperature differences in spindle units limits the application of thermoelectric generation to drive a wireless sensor. This study is devoted to presenting a transformer-based power management system and its associated control strategy to make the wireless sensor work stably at different speeds of the spindle. The charging/discharging time of capacitors is optimized through this energy-harvesting strategy. A rotating spindle platform is set up to test the performance of the power management system at different speeds. The experimental results show that a longer sampling cycle time will increase the stability of the wireless sensor. The experiments also prove that utilizing the optimal time can make the power management system work more effectively compared with other systems using the same sample cycle. PMID:25033189

Li, Sheng; Yao, Xinhua; Fu, Jianzhong

2014-01-01

190

Research on a Power Management System for Thermoelectric Generators to Drive Wireless Sensors on a Spindle Unit  

PubMed Central

Thermoelectric energy harvesting is emerging as a promising alternative energy source to drive wireless sensors in mechanical systems. Typically, the waste heat from spindle units in machine tools creates potential for thermoelectric generation. However, the problem of low and fluctuant ambient temperature differences in spindle units limits the application of thermoelectric generation to drive a wireless sensor. This study is devoted to presenting a transformer-based power management system and its associated control strategy to make the wireless sensor work stably at different speeds of the spindle. The charging/discharging time of capacitors is optimized through this energy-harvesting strategy. A rotating spindle platform is set up to test the performance of the power management system at different speeds. The experimental results show that a longer sampling cycle time will increase the stability of the wireless sensor. The experiments also prove that utilizing the optimal time can make the power management system work more effectively compared with other systems using the same sample cycle. PMID:25033189

Li, Sheng; Yao, Xinhua; Fu, Jianzhong

2014-01-01

191

Research on the Compatibility of the Cooling Unit in an Automotive Exhaust-based Thermoelectric Generator and Engine Cooling System  

NASA Astrophysics Data System (ADS)

The temperature difference between the hot and cold sides of thermoelectric modules is a key factor affecting the conversion efficiency of an automotive exhaust-based thermoelectric generator (TEG). In the work discussed in this paper the compatibility of TEG cooling unit and engine cooling system was studied on the basis of the heat transfer characteristics of the TEG. A new engine-cooling system in which a TEG cooling unit was inserted was simulated at high power and high vehicle speed, and at high power and low vehicle speed, to obtain temperatures and flow rates of critical inlets and outlets. The results show that coolant temperature exceeds its boiling point at high power and low vehicle speed, so the new system cannot meet cooling requirements under these conditions. Measures for improvement to optimize the cooling system are proposed, and provide a basis for future research.

Deng, Y. D.; Liu, X.; Chen, S.; Xing, H. B.; Su, C. Q.

2014-06-01

192

Experiments and Simulations on a Heat Exchanger of an Automotive Exhaust Thermoelectric Generation System Under Coupling Conditions  

NASA Astrophysics Data System (ADS)

The present experimental and computational study investigates an exhaust gas waste heat recovery system for vehicles, using thermoelectric modules and a heat exchanger to produce electric power. It proposes a new plane heat exchanger of a thermoelectric generation (TEG) system, producing electricity from a limited hot surface area. To investigate the new plane heat exchanger, we make a coupling condition of heat-flow and flow-solid coupling analysis on it to obtain the temperature, heat, and pressure field of the heat exchanger, and compared it with the old heat exchanger. These fields couple together to solve the multi-field coupling of the flow, solid, and heat, and then the simulation result is compared with the test bench experiment of TEG, providing a theoretical and experimental basis for the present exhaust gas waste heat recovery system.

Liu, X.; Yu, C. G.; Chen, S.; Wang, Y. P.; Su, C. Q.

2014-06-01

193

Using thermoelectric nuclear power generators in spacecraft power-generation propulsion complexes  

Microsoft Academic Search

Power-generation and propulsion complexes for spacecraft, universal space platforms (US) which combine a power unit and high- and low-thrust propulsion unions, make it possible to efficiently solve problems involved in creating satellite communication systems, environmental monitoring systems, industrial technology platforms, interorbital shuttles, etc. Electrical power consumed by prospective spacecraft designed for communication or environmental monitoring may be as high as

P. V. Andreev; A. Ya. Galkin; G. M. Gryaznov

1994-01-01

194

Cooling, Heating, Generating Power, and Recovering Waste Heat with Thermoelectric Systems  

NASA Astrophysics Data System (ADS)

Thermoelectric materials are solid-state energy converters whose combination of thermal, electrical, and semiconducting properties allows them to be used to convert waste heat into electricity or electrical power directly into cooling and heating. These materials can be competitive with fluid-based systems, such as two-phase air-conditioning compressors or heat pumps, or used in smaller-scale applications such as in automobile seats, night-vision systems, and electrical-enclosure cooling. More widespread use of thermoelectrics requires not only improving the intrinsic energy-conversion efficiency of the materials but also implementing recent advancements in system architecture. These principles are illustrated with several proven and potential applications of thermoelectrics.

Bell, Lon E.

2008-09-01

195

Stresa, Italy, 26-28 April 2006 ENERGY CONVERSION USING NEW THERMOELECTRIC GENERATOR  

E-print Network

components. First Bi and Sb micro-devices on silicon glass substrate have been manufactured with an area of 1 thermoelectric materials (TE) are here bismuth and antimony. Both Bi and Sb are semimetals, that is We use a four inches glass substrate. 42 chips and 6 test areas are distributed on it. Fig.1. shows

Paris-Sud XI, Université de

196

MeV Si ion modifications on the thermoelectric generators from Si/Si + Ge superlattice nano-layered films  

NASA Astrophysics Data System (ADS)

The performance of thermoelectric materials and devices is characterized by a dimensionless figure of merit, ZT = S2?T/K, where, S and ? denote, respectively, the Seebeck coefficient and electrical conductivity, T is the absolute temperature in Kelvin and K represents the thermal conductivity. The figure of merit may be improved by means of raising either S or ? or by lowering K. In our laboratory, we have fabricated and characterized the performance of a large variety of thermoelectric generators (TEG). Two TEG groups comprised of 50 and 100 alternating layers of Si/Si + Ge multi-nanolayered superlattice films have been fabricated and thoroughly characterized. Ion beam assisted deposition (IBAD) was utilized to assemble the alternating sandwiched layers, resulting in total thickness of 300 nm and 317 nm for 50 and 100 layer devices, respectively. Rutherford Backscattering Spectroscopy (RBS) was employed in order to monitor the precise quantity of Si and Ge utilized in the construction of specific multilayer thin films. The material layers were subsequently impregnated with quantum dots and/or quantum clusters, in order to concurrently reduce the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and raise the cross plane electrical conductivity. The quantum dots/clusters were implanted via the 5 MeV Si ion bombardment which was performed using a Pelletron high energy ion beam accelerator. We have achieved remarkable results for the thermoelectric and optical properties of the Si/Si + Ge multilayer thin film TEG systems. We have demonstrated that with optimal setting of the 5 MeV Si ion beam bombardment fluences, one can fabricate TEG systems with figures of merits substantially higher than the values previously reported.

Budak, S.; Heidary, K.; Johnson, R. B.; Colon, T.; Muntele, C.; Ila, D.

2014-08-01

197

Laboratory development TPV generator  

SciTech Connect

A laboratory model of a TPV generator in the kilowatt range was developed and tested. It was based on methane/oxygen combustion and a spectrally matched selective emitter/collector pair (ytterbia emitter-silicon PV cell). The system demonstrated a power output of 2.4 kilowatts at an overall efficiency of 4.5{percent} without recuperation of heat from the exhaust gases. Key aspects of the effort include: (1) process development and fabrication of mechanically strong selective emitter ceramic textile materials; (2) design of a stirred reactor emitter/burner capable of handling up to 175,000 Btu/hr fuel flows; (3) support to the developer of the production silicon concentrator cells capable of withstanding TPV environments; (4) assessing the apparent temperature exponent of selective emitters; and (5) determining that the remaining generator efficiency improvements are readily defined combustion engineering problems that do not necessitate breakthrough technology. The fiber matrix selective emitter ceramic textile (felt) was fabricated by a relic process with the final heat-treatment controlling the grain growth in the porous ceramic fiber matrix. This textile formed a cylindrical cavity for a stirred reactor. The ideal stirred reactor is characterized by constant temperature combustion resulting in a uniform reactor temperature. This results in a uniform radiant emission from the emitter. As a result of significant developments in the porous emitter matrix technology, a TPV generator burner/emitter was developed that produced kilowatts of radiant energy. {copyright} {ital 1996 American Institute of Physics.}

Holmquist, G.A.; Wong, E.M. [Quantum Group, Inc., 11211 Sorrento Valley Road, San Diego, California 92121 (United States); Waldman, C.H. [Consultant, P.O. Box 231157, Encinitas, California 92023-1157 (United States)

1996-02-01

198

PV-hybrid and thermoelectric collectors  

Microsoft Academic Search

Two different principles of thermoelectric cogeneration solar collectors have been realized and investigated. Concerning the first principle, the thermoelectric collector (TEC) delivers electricity indirectly by first producing heat and subsequently generating electricity by means of a thermoelectric generator. Concerning the second principle, the photovoltaic-hybrid collector (PVHC) uses photovoltaic cells, which are cooled by a liquid heat-transfer medium. The characteristics of

Gunter Rockendorf; Roland Sillmann; Lars Podlowski; Bernd Litzenburger

1999-01-01

199

Comparison of the Various Methodologies for Estimating Thermoelectric Power Generation Water Withdrawals and Their Effect on Water-Use Trends from 1985-2010 in the United States  

NASA Astrophysics Data System (ADS)

The U.S Geological Survey (USGS) has estimated thermoelectric water withdrawals at 5-year intervals since 1950, and consumptive use from 1950 to 1995. Changes in water demand for cooling water, a significant part of the thermoelectric water use, has important implications for water availability to meet future energy demand, especially at the local level. USGS data show total water withdrawals peaked in 1980, declined in 1985, and have remained relatively stable through 2005. Total water use has been dominated by thermoelectric withdrawals since 1965. USGS estimates through 2005 have been primarily based on compiling self-reported data by powerplant operators to State water regulatory agencies and to the Department of Energy-Energy Information Administration (EIA). The reported data from these sources have often been inconsistent because techniques for measuring or estimating the main water flows are not standardized; and, incomplete because reporting thresholds for water withdrawals vary from State-to-State. EIA only requires the reporting of water use from powerplants that are 100 megawatts or more. Some withdrawals have also been estimated with a gallon per kilowatt-hour coefficient and powerplant net electric generation; however, coefficients were mostly based on reported data, and although the coefficients accounted for differences in cooling systems, fuel type, and flue gas desulfurization and other factors, the coefficients are averages and have not accounted for either weather or climatic conditions. The USGS National Water Use Information Program (NWUIP) developed consistent estimates of water withdrawals and water consumption based on linked heat and water budgets for the entire fleet of 1,284 active water-using powerplants for 2010. In 2010, 802 powerplants reported water-use data to EIA. The linked heat and water budget calculates condenser duty for a powerplant, and estimated water withdrawal is a function of condenser duty and change in temperature in the cooling water. Condenser duty is the amount of waste heat delivered to the cooling system through the condenser. The modeled water withdrawal results were expressed as a single value for each powerplant along with a minimum and maximum that bracketed a thermodynamically reasonable range of values. This range also provided a quality assurance check for other self-reported operator or coefficient derived water withdrawal estimates for a powerplant. To varying degrees, the USGS modeled results differed from the self-reported operator values used by most USGS State offices for the 2010 national compilation. Importantly, these two USGS nationally-generated sets of 2010 withdrawal values show a notable shift in the relatively stable thermoelectric water-use trend from 1985 to 2005. To understand the shift in the 2010 thermoelectric withdrawal estimates, the methodologies were analyzed by comparing EIA reported data for 1985, 1990, 1995, 2000, and 2005 to USGS national compilation estimates for the same years. Further, 2010 self-reported water withdrawal data from EIA, the USGS national compilation data, and USGS model results were also compared.

Hutson, S.

2013-12-01

200

Determination of Thermoelectric Module Efficiency A Survey  

SciTech Connect

The development of thermoelectrics (TE) for energy conversion is in the transition phase from laboratory research to device development. There is an increasing demand to accurately determine the module efficiency, especially for the power generation mode. For many thermoelectrics, the figure of merit, ZT, of the material sometimes cannot be fully realized at the device level. Reliable efficiency testing of thermoelectric modules is important to assess the device ZT and provide the end-users with realistic values on how much power can be generated under specific conditions. We conducted a general survey of efficiency testing devices and their performance. The results indicated the lack of industry standards and test procedures. This study included a commercial test system and several laboratory systems. Most systems are based on the heat flow meter method and some are based on the Harman method. They are usually reproducible in evaluating thermoelectric modules. However, cross-checking among different systems often showed large errors that are likely caused by unaccounted heat loss and thermal resistance. Efficiency testing is an important area for the thermoelectric community to focus on. A follow-up international standardization effort is planned.

Wang, Hsin [ORNL; McCarty, Robin [Marlow Industries, Inc; Salvador, James R. [GM R& D and Planning, Warren, Michigan; Yamamoto, Atsushi [AIST, Japan; Konig, Jan [Fraunhofer-Institute, Freiburg, Germany

2014-01-01

201

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

NASA Astrophysics Data System (ADS)

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 ? 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.

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

2012-06-01

202

Load following characteristics of SiGe/GaP thermoelectric generators and their response to external heating  

SciTech Connect

This paper discusses the load following characteristics of SiGe/GaP thermoelectric (TE) generators during both steady-state and transient changes of the external load. It also investigates the performance of TE generators as they are subjected to an external heating at their cold shoes. Results show that TE generators are load following within a narrow range of external load values and that external heating impairs their performance. The load following behavior of TE generators was found to be independent of the rate of changing the external load (steady state or ramp). For a constant hot shoe temperature, external heating of the TE generators caused their cold shoe temperature to rise and consequently increased the rate of heat rejection by radiation and decreased the electric power output. Because of the enhancement in the heat rejection by radiation during the external heating of the TE generators, a large heating rate is required for the generators to cease operation. The tolerance of TE generators to external heating can effectively be increased by initially raising the TE cold shoe temperature.

El-Genk, M.S.; Seo, J.T.; Buksa, J.J.

1987-03-01

203

Printable thermoelectric devices and conductive patterns for medical applications  

NASA Astrophysics Data System (ADS)

Remote point-of-care is expected to revolutionize the modern medical practice, and many efforts have been made for the development of wireless health monitoring systems for continuously detecting the physiological signals of patients. To make the remote point-of-care generally accepted and widely used, it is necessary to develop cost-effective and durable wireless health monitoring systems. Printing technique will be helpful for the fabrication of high-quality and low-cost medical devices and systems because it allows high-resolution and high-speed fabrication, low material consumption and nano-sized patterning on both flexible and rigid substrates. Furthermore, application of thermoelectric generators can replace conventional batteries as the power sources for wireless health monitoring systems because thermoelectric generators can convert the wasted heat or the heat from nature into electricity which is required for the operation of the wireless health monitoring systems. In this research, we propose the concept of printable thermoelectric devices and conductive patterns for the realization of more portable and cost-effective medical devices. To print thermoelectric generators and conductive patterns on substrates, printing inks with special characteristics should be developed. For the development of thermoelectric inks, nano-structured thermoelectric materials are synthesized and characterized; and for the development of conductive inks, two kinds of surface treated carbon nanotubes are used as active materials.

Lee, Jungmin; Kim, Hyunjung; Chen, Linfeng; Choi, Sang H.; Varadan, Vijay K.

2012-10-01

204

Organic thermoelectric materials: emerging green energy materials converting heat to electricity directly and efficiently.  

PubMed

The abundance of solar thermal energy and the widespread demands for waste heat recovery make thermoelectric generators (TEGs) very attractive in harvesting low-cost energy resources. Meanwhile, thermoelectric refrigeration is promising for local cooling and niche applications. In this context there is currently a growing interest in developing organic thermoelectric materials which are flexible, cost-effective, eco-friendly and potentially energy-efficient. In particular, the past several years have witnessed remarkable progress in organic thermoelectric materials and devices. In this review, thermoelectric properties of conducting polymers and small molecules are summarized, with recent progresses in materials, measurements and devices highlighted. Prospects and suggestions for future research efforts are also presented. The organic thermoelectric materials are emerging candidates for green energy conversion. PMID:24687930

Zhang, Qian; Sun, Yimeng; Xu, Wei; Zhu, Daoben

2014-10-01

205

Nanocomposites for thermoelectric power generation: rare-earth metal monoantimonide nanostructures embedded in InGaSb and InSbAs ternary alloys  

NASA Astrophysics Data System (ADS)

Thermoelectric figure of merit (ZT) depends on three material properties; electrical conductivity, thermal conductivity, and Seebeck coefficient. Maximizing ZT simply requires that electrical conductivity and Seebeck coefficient be high to reduce Joule heating and to increase energy conversion efficiency while thermal conductivity needs to be low to maintain temperature gradient across a thermoelectric material. Unfortunately these three material properties are closely correlated each other in homogeneous bulk semiconductors. Recent demonstrations that employ various semiconductor materials tuned at the nanometer-scale (nanomaterials) have shown great promise in advancing thermoelectrics. Among a wide range of nanomaterials, we focus on "nanocomposites" in which semimetallic nanostructures are epitaxially embedded in a ternary compound semiconductor matrix to attempt tuning the three material properties independently. We demonstrated co-deposition of erbium monoantimonide (ErSb) and In1-xGaxSb or InSb1-yAsy ternary alloy to form nanometer-scale semimetallic ErSb structures within these ternary alloys "nanocomposite" using low-pressure metal organic chemical vapor deposition. The grown nanocomposites were structurally and thermoelectrically analyzed to assess their potential for advanced thermoelectric power generation.

Norris, Kate J.; Onishi, Takehiro; Lohn, Andrew J.; Padgaonkar, Nitish; Wong, Vernon; Coleman, Elane; Tompa, Gary S.; Kobayashi, Nobuhiko P.

2011-10-01

206

Thermoelectric micro devices: current state, recent developments and future aspects for technological progress and applications  

Microsoft Academic Search

Due to their unique expected properties thermoelectric microdevices, thermogenerators as well as Peltier coolers, are of high demand for different applications namely for telecommunication purposes. Thus worldwide efforts are undertaken to expand the technology for thermoelectric devices into the field of typical microsystem technologies including aspects of advanced low dimensional high ZT materials. Favourite material systems are up to now

H. Bottner

2002-01-01

207

Thermoelectric Conversion of Waste Heat to Electricity in an IC Engine Powered Vehicle  

SciTech Connect

The thermoelectric generator shorting system provides the capability to monitor and short-out individual thermoelectric couples in the event of failure. This makes the series configured thermoelectric generator robust to individual thermoelectric couple failure. Open circuit detection of the thermoelectric couples and the associated short control is a key technique to ensure normal functionality of the TE generator under failure of individual TE couples. This report describes a five-year effort whose goal was the understanding the issues related to the development of a thermoelectric energy recovery device for a Class-8 truck. Likely materials and important issues related to the utility of this generator were identified. Several prototype generators were constructed and demonstrated. The generators developed demonstrated several new concepts including advanced insulation, couple bypass technology and the first implementation of skutterudite thermoelectric material in a generator design. Additional work will be required to bring this system to fruition. However, such generators offer the possibility of converting energy that is otherwise wasted to useful electric power. Uur studies indicate that this can be accomplished in a cost-effective manner for this application.

None

2012-01-31

208

Development of High Efficiency Segmented Thermoelectric Unicouples T. Caillat, J. -P. Fleurial, G. J. Snyder, and A. Borshchevsky  

E-print Network

Propulsion Laboratory (JPL) under the sponsorship of the U. S. Defense Advanced Research Projects Agency efficient, segmented thermoelectric unicouples incorporating advanced thermoelectric materials with superior have been measured. Introduction A segmented thermoelectric unicouple incorporating advanced

209

Selection and Evaluation of Thermal Interface Materials for Reduction of the Thermal Contact Resistance of Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

A variety of thermal interface materials (TIMs) were investigated to find a suitable TIM for improving the performance of thermoelectric power generators (TEGs) operating in the medium-temperature range (600-900 K). The thermal resistance at the thermal interface between which the TIM was inserted was evaluated. The TIMs were chosen on the basis of their thermal stability when used with TEGs operating at medium temperatures, their electrical insulating properties, their thermal conductivity, and their thickness. The results suggest that the boron nitride (BN)-based ceramic coating, Whity Paint, and the polyurethane-based sheet, TSU700-H, are suitable TIMs for the heat source and heat sink sides, respectively, of the TEG. Use of these effectively enhances TEG performance because they reduce the thermal contact resistance at the thermal interface.

Sakamoto, Tatsuya; Iida, Tsutomu; Sekiguchi, Takeshi; Taguchi, Yutaka; Hirayama, Naomi; Nishio, Keishi; Takanashi, Yoshifumi

2014-10-01

210

Advanced Thermoelectric Materials for Efficient Waste Heat Recovery in Process Industries  

SciTech Connect

The overall objective of the project was to integrate advanced thermoelectric materials into a power generation device that could convert waste heat from an industrial process to electricity with an efficiency approaching 20%. Advanced thermoelectric materials were developed with figure-of-merit ZT of 1.5 at 275 degrees C. These materials were not successfully integrated into a power generation device. However, waste heat recovery was demonstrated from an industrial process (the combustion exhaust gas stream of an oxyfuel-fired flat glass melting furnace) using a commercially available (5% efficiency) thermoelectric generator coupled to a heat pipe. It was concluded that significant improvements both in thermoelectric material figure-of-merit and in cost-effective methods for capturing heat would be required to make thermoelectric waste heat recovery viable for widespread industrial application.

Adam Polcyn; Moe Khaleel

2009-01-06

211

Thermopower Study of GaN-Based Materials for Next-Generation Thermoelectric Devices and Applications  

NASA Astrophysics Data System (ADS)

III-nitride InGaN-based solar cells have gained importance because their band gap can potentially cover most of the solar spectrum, spanning 0.7 eV to 3.4 eV. However, to use these materials to harvest additional energy, other properties such as their thermoelectric properties should be exploited. In this work, the Seebeck coefficient and the electrical conductivity of three InGaN alloys with various indium concentrations and Gd-doped GaN (GaN:Gd) were measured, and the power factor was calculated. We report a Seebeck value of ˜209 ?V/K for Gd-doped GaN.

Hurwitz, Elisa N.; Asghar, Muhammad; Melton, Andrew; Kucukgok, Bahadir; Su, Liqin; Orocz, Mateusz; Jamil, Muhammad; Lu, Na; Ferguson, Ian T.

2011-05-01

212

Silicon nanowires as efficient thermoelectric materials  

Microsoft Academic Search

Thermoelectric materials interconvert thermal gradients and electric fields for power generation or for refrigeration. Thermoelectrics currently find only niche applications because of their limited efficiency, which is measured by the dimensionless parameter ZT-a function of the Seebeck coefficient or thermoelectric power, and of the electrical and thermal conductivities. Maximizing ZT is challenging because optimizing one physical parameter often adversely affects

Akram I. Boukai; Yuri Bunimovich; Jamil Tahir-Kheli; Jen-Kan Yu; William A. Goddard III; James R. Heath

2008-01-01

213

Multilayer thermoelectric films: A strategy for the enhancement of ZT  

SciTech Connect

The relative efficiency of a thermoelectric material is measured in terms of a dimensionless figure of merit, ZT. Although all known thermoelectric materials are believed to have ZT {le} 1, recent theoretical results predict that thermoelectric devices fabricated as two-dimensional quantum wells (2D QWs) could have ZT {ge} 3. Multilayers with the dimensions of 2D QWs have been synthesized by alternately sputtering Bi{sub 0.9}Sb{sub 0.1} and PbTe{sub 0.8}Se{sub 0.2} onto a moving substrate from a pair of magnetron sources. These materials have been synthesized to test the thermoelectric quantum-well concept and gain insight into relevant transport mechanisms. This work focuses primarily on the scientific issues involved in producing the materials necessary to examine the possibility of enhancing ZT using quantum confinement. The techniques needed to measure the relevant electrical parameters of thermoelectric thin films are developed in this paper. Ultimately, if a quantum well enhancement of thermoelectrics is experimentally observed, devices based on this technology could be used to greatly expand the role of thermoelectrics in power generation and refrigeration.

Wadgner, A.V.; Foreman, R.J.; Summers, L.J.; Barbee, T.W. Jr.; Farmer, J.C.

1995-03-01

214

Shockwave consolidation of nanostructured thermoelectric materials  

NASA Astrophysics Data System (ADS)

Nanotechnology based thermoelectric materials are considered attractive for developing highly efficient thermoelectric devices. Nano-structured thermoelectric materials are predicted to offer higher ZT over bulk materials by reducing thermal conductivity and increasing electrical conductivity. Consolidation of nano-structured powders into dense materials without losing nanostructure is essential towards practical device development. Using the gas atomization process, amorphous nano-structured powders were produced. Shockwave consolidation is accomplished by surrounding the nanopowder-containing tube with explosives and then detonated. The resulting shock wave causes rapid fusing of the powders without the melt and subsequent grain growth. We have been successful in generating consolidated nanostructured bismuth telluride alloy powders by using shockwave technique. Using these consolidated materials, several types of thermoelectric power generator devices have been developed. Shockwave consolidation is anticipated to generate large quantities of nanostructred materials expeditiously and cost effectively. In this paper, the technique of shockwave consolidation will be presented followed by Seebeck Coefficient and thermal conductivity measurements of consolidated materials. Preliminary results indicate a substantial increase in electrical conductivity due to shockwave consolidation technique.

Prasad, Narasimha S.; Taylor, Patrick; Nemir, David

2014-09-01

215

Thermoelectric Devices Advance Thermal Management  

NASA Technical Reports Server (NTRS)

Thermoelectric (TE) devices heat, cool, and generate electricity when a temperature differential is provided between the two module faces. In cooperation with NASA, Chico, California-based United States Thermoelectric Consortium Inc. (USTC) built a gas emissions analyzer (GEA) for combustion research. The GEA precipitated hydrocarbon particles, preventing contamination that would hinder precise rocket fuel analysis. The USTC research and design team uses patent-pending dimple, pin-fin, microchannel and microjet structures to develop and design heat dissipation devices on the mini-scale level, which not only guarantee high performance of products, but also scale device size from 1 centimeter to 10 centimeters. USTC continues to integrate the benefits of TE devices in its current line of thermal management solutions and has found the accessibility of NASA technical research to be a valuable, sustainable resource that has continued to positively influence its product design and manufacturing

2007-01-01

216

Thermoelectric module  

DOEpatents

A thermoelectric module containing lead telluride as the thermoelectric mrial is encapsulated as tightly as possible in a stainless steel canister to provide minimum void volume in the canister. The lead telluride thermoelectric elements are pressure-contacted to a tungsten hot strap and metallurgically bonded at the cold junction to iron shoes with a barrier layer of tin telluride between the iron shoe and the p-type lead telluride element.

Kortier, William E. (Columbus, OH); Mueller, John J. (Columbus, OH); Eggers, Philip E. (Columbus, OH)

1980-07-08

217

Thermoelectric-Driven Autonomous Sensors for a Biomass Power Plant  

NASA Astrophysics Data System (ADS)

This work presents the design and development of a thermoelectric generator intended to harness waste heat in a biomass power plant, and generate electric power to operate sensors and the required electronics for wireless communication. The first objective of the work is to design the optimum thermoelectric generator to harness heat from a hot surface, and generate electric power to operate a flowmeter and a wireless transmitter. The process is conducted by using a computational model, presented in previous papers, to determine the final design that meets the requirements of electric power consumption and number of transmissions per minute. Finally, the thermoelectric generator is simulated to evaluate its performance. The final device transmits information every 5 s. Moreover, it is completely autonomous and can be easily installed, since no electric wires are required.

Rodríguez, A.; Astrain, D.; Martínez, A.; Gubía, E.; Sorbet, F. J.

2013-07-01

218

Development of a thermoelectric one-man cooler for use by NASA astronauts  

SciTech Connect

This paper presents the development of a one-man thermoelectric (TE) cooling unit designed for use by NASA astronauts while they are wearing a protective suit during the launch and reentry phases of space shuttle missions. The unit was designed to provide a low-cooling level of 340 Btu/hour in a 75{degree}F environment and a high-cooling level of 480 Btu/hour in a 95{degree}F environment. The unit has an envelope 8 inches wide by 11 inches high by 4.5 inches deep. The TE unit was designed to optimize space and power consumption while providing adequate cooling. The operation of the TE cooling unit requires {similar_to}1.2 amps of 28 VDC power in the low power mode and {similar_to}3.0 amps of 28 VDC power in the high power mode. Two of these units have flown on several shuttle missions this year and are scheduled for continued use on future missions. The response to the TE unit`s performance has been very positive from the shuttle crew. Additional units are being fabricated to keep the shuttle crew members cooled while final development is under way. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Heenan, P.; Mathiprakasam, B.; DeMott, D. [Midwest Research Institute, Kansas City, Missouri 64110 (United States)

1994-08-10

219

Hybrid Solid Oxide Fuel Cell and Thermoelectric Generator for Maximum Power Output in Micro-CHP Systems  

NASA Astrophysics Data System (ADS)

One of the most obvious early market applications for thermoelectric generators (TEG) is decentralized micro combined heat and power (CHP) installations of 0.5 kWe to 5 kWe based on fuel cell technology. Through the use of TEG technology for waste heat recovery it is possible to increase the electricity production in micro-CHP systems by more than 15%, corresponding to system electrical efficiency increases of some 4 to 5 percentage points. This will make fuel cell-based micro-CHP systems very competitive and profitable and will also open opportunities in a number of other potential business and market segments which are not yet quantified. This paper quantifies a micro-CHP system based on a solid oxide fuel cell (SOFC) and a high-performance TE generator. Based on a 3 kW fuel input, the hybrid SOFC implementation boosts electrical output from 945 W to 1085 W, with 1794 W available for heating purposes.

Rosendahl, L. A.; Mortensen, Paw V.; Enkeshafi, Ali A.

2011-05-01

220

Determination of Thermoelectric Module Efficiency: A Survey  

NASA Astrophysics Data System (ADS)

The development of thermoelectrics (TE) for energy conversion is in the transition phase from laboratory research to device development. There is an increasing demand to accurately determine the module efficiency, especially for the power generation mode. For many TE, the figure of merit, ZT, of the material sometimes cannot be fully realized at the device level. Reliable efficiency testing of thermoelectric modules is important to assess the device ZT and provide end-users with realistic values for how much power can be generated under specific conditions. We conducted a general survey of efficiency testing devices and their performance. The results indicated a lack of industry standards and test procedures. This study included a commercial test system and several laboratory systems. Most systems are based on the heat flow meter method, and some are based on the Harman method. They are usually reproducible in evaluating thermoelectric modules. However, different systems often showed large differences that are likely caused by uncertain heat loss and thermal resistance. Efficiency testing is an important capability for the thermoelectric community to improve. A follow-up international standardization effort is planned.

Wang, Hsin; McCarty, Robin; Salvador, James R.; Yamamoto, Atsushi; König, Jan

2014-06-01

221

Modeling the thermoelectric properties of bulk and nanocomposite thermoelectric materials  

E-print Network

Thermoelectric materials are materials which are capable of converting heat directly into electricity. They have long been used in specialized fields where high reliability is needed, such as space power generation. Recently, ...

Minnich, Austin (Austin Jerome)

2008-01-01

222

A Power Conditioning Stage Based on Analog-Circuit MPPT Control and a Superbuck Converter for Thermoelectric Generators in Spacecraft Power Systems  

NASA Astrophysics Data System (ADS)

A thermoelectric generator (TEG) is a very important kind of power supply for spacecraft, especially for deep-space missions, due to its long lifetime and high reliability. To develop a practical TEG power supply for spacecraft, a power conditioning stage is indispensable, being employed to convert the varying output voltage of the TEG modules to a definite voltage for feeding batteries or loads. To enhance the system reliability, a power conditioning stage based on analog-circuit maximum-power-point tracking (MPPT) control and a superbuck converter is proposed in this paper. The input of this power conditioning stage is connected to the output of the TEG modules, and the output of this stage is connected to the battery and loads. The superbuck converter is employed as the main circuit, featuring low input current ripples and high conversion efficiency. Since for spacecraft power systems reliable operation is the key target for control circuits, a reset-set flip-flop-based analog circuit is used as the basic control circuit to implement MPPT, being much simpler than digital control circuits and offering higher reliability. Experiments have verified the feasibility and effectiveness of the proposed power conditioning stage. The results show the advantages of the proposed stage, such as maximum utilization of TEG power, small input ripples, and good stability.

Sun, Kai; Wu, Hongfei; Cai, Yan; Xing, Yan

2014-06-01

223

An air-breathing, portable thermoelectric power generator based on a microfabricated silicon combustor  

E-print Network

The global consumer demand for portable electronic devices is increasing. The emphasis on reducing size and weight has put increased pressure on the power density of available power storage and generation options, which ...

Marton, Christopher Henry

2011-01-01

224

Thermal Expansion Studies of Selected High-Temperature Thermoelectric Materials  

NASA Astrophysics Data System (ADS)

Radioisotope thermoelectric generators (RTGs) generate electrical power by converting the heat released from the nuclear decay of radioactive isotopes (typically plutonium-238) into electricity using a thermoelectric converter. RTGs have been successfully used to power a number of space missions and have demonstrated their reliability over an extended period of time (tens of years) and are compact, rugged, radiation resistant, scalable, and produce no noise, vibration or torque during operation. System conversion efficiency for state-of-practice RTGs is about 6% and specific power ?5.1 W/kg. A higher specific power would result in more onboard power for the same RTG mass, or less RTG mass for the same onboard power. The Jet Propulsion Laboratory has been leading, under the advanced thermoelectric converter (ATEC) project, the development of new high-temperature thermoelectric materials and components for integration into advanced, more efficient RTGs. Thermoelectric materials investigated to date include skutterudites, the Yb14MnSb11 compound, and SiGe alloys. The development of long-lived thermoelectric couples based on some of these materials has been initiated and is assisted by a thermomechanical stress analysis to ensure that all stresses under both fabrication and operation conditions will be within yield limits for those materials. Several physical parameters are needed as input to this analysis. Among those parameters, the coefficient of thermal expansion (CTE) is critically important. Thermal expansion coefficient measurements of several thermoelectric materials under consideration for ATEC are described in this paper. The stress response at the interfaces in material stacks subjected to changes in temperature is discussed, drawing on work from the literature and project-specific tools developed here. The degree of CTE mismatch and the associated effect on the formation of stress is highlighted.

Ravi, Vilupanur; Firdosy, Samad; Caillat, Thierry; Brandon, Erik; van der Walde, Keith; Maricic, Lina; Sayir, Ali

2009-07-01

225

Application of thermoelectric cooling to electronic equipment: a review and analysis  

Microsoft Academic Search

This paper provides a review of thermoelectric cooling and its application to the cooling of electronic equipment. A background discussion of thermoelectric cooling is provided briefly citing early history, current developments, and the defining thermoelectric heat pumping equations. Several examples are provided of early IBM applications of thermoelectric cooling. An analysis to assess thermoelectric cooling enhancement in terms of increases

R. E. Simons; R. C. Chu

2000-01-01

226

Advanced Radioisotope Power Systems Segmented Thermoelectric Research  

NASA Technical Reports Server (NTRS)

Flight times are long; - Need power systems with >15 years life. Mass is at an absolute premium; - Need power systems with high specific power and scalability. 3 orders of magnitude reduction in solar irradiance from Earth to Pluto. Nuclear power sources preferable. The Overall objective is to develop low mass, high efficiency, low-cost Advanced Radioisotope Power System with double the Specific Power and Efficiency over state-of-the-art Radioisotope Thermoelectric Generators (RTGs).

Caillat, Thierry

2004-01-01

227

Test System for Thermoelectric Modules and Materials  

NASA Astrophysics Data System (ADS)

We present a design for a complex measuring device that enables its user to assess the parameters of power-generating thermoelectric modules (TEMs) (or bulk thermoelectric materials) under a wide range of temperatures ( T cold = 25°C to 90°C, T hot < 450°C) and mechanical loading ( P = 0 N to 104 N). The proposed instrument is able to monitor the temperature and electrical output of the TEM, the actual heat flow through the module, and its mechanical load, which can be varied during the measurement. Key components of our testing setup are (i) a measuring chamber where the TEM/material is compressed between thermally shielded heating blocks equipped with a mechanical loading system and water-cooled copper-based cooler, (ii) an electrical load system, (iii) a type K thermocouple array connected to a data acquisition computer, and (iv) a thermostatic water-based cooling system with electronically controlled flow rate and temperature of cooling water. Our testing setup represents a useful tool able to assess, e.g., the thermoelectric parameters of newly developed TEMs and materials or to evaluate the thermoelectric parameters of commercially available modules and materials for comparison with values declared by the manufacturer.

Hejtmánek, J.; Knížek, K.; Švejda, V.; Horna, P.; Sikora, M.

2014-10-01

228

Nano-materials Enabled Thermoelectricity from Window Glasses  

PubMed Central

With a projection of nearly doubling up the world population by 2050, we need wide variety of renewable and clean energy sources to meet the increased energy demand. Solar energy is considered as the leading promising alternate energy source with the pertinent challenge of off sunshine period and uneven worldwide distribution of usable sun light. Although thermoelectricity is considered as a reasonable renewable energy from wasted heat, its mass scale usage is yet to be developed. Here we show, large scale integration of nano-manufactured pellets of thermoelectric nano-materials, embedded into window glasses to generate thermoelectricity using the temperature difference between hot outside and cool inside. For the first time, this work offers an opportunity to potentially generate 304 watts of usable power from 9 m2 window at a 20°C temperature gradient. If a natural temperature gradient exists, this can serve as a sustainable energy source for green building technology. PMID:23150789

Inayat, Salman B.; Rader, Kelly R.; Hussain, Muhammad M.

2012-01-01

229

Nano-materials Enabled Thermoelectricity from Window Glasses  

NASA Astrophysics Data System (ADS)

With a projection of nearly doubling up the world population by 2050, we need wide variety of renewable and clean energy sources to meet the increased energy demand. Solar energy is considered as the leading promising alternate energy source with the pertinent challenge of off sunshine period and uneven worldwide distribution of usable sun light. Although thermoelectricity is considered as a reasonable renewable energy from wasted heat, its mass scale usage is yet to be developed. Here we show, large scale integration of nano-manufactured pellets of thermoelectric nano-materials, embedded into window glasses to generate thermoelectricity using the temperature difference between hot outside and cool inside. For the first time, this work offers an opportunity to potentially generate 304 watts of usable power from 9 m2 window at a 20°C temperature gradient. If a natural temperature gradient exists, this can serve as a sustainable energy source for green building technology.

Inayat, Salman B.; Rader, Kelly R.; Hussain, Muhammad M.

2012-11-01

230

Band engineering of thermoelectric materials.  

PubMed

Lead chalcogenides have long been used for space-based and thermoelectric remote power generation applications, but recent discoveries have revealed a much greater potential for these materials. This renaissance of interest combined with the need for increased energy efficiency has led to active consideration of thermoelectrics for practical waste heat recovery systems-such as the conversion of car exhaust heat into electricity. The simple high symmetry NaCl-type cubic structure, leads to several properties desirable for thermoelectricity, such as high valley degeneracy for high electrical conductivity and phonon anharmonicity for low thermal conductivity. The rich capabilities for both band structure and microstructure engineering enable a variety of approaches for achieving high thermoelectric performance in lead chalcogenides. This Review focuses on manipulation of the electronic and atomic structural features which makes up the thermoelectric quality factor. While these strategies are well demonstrated in lead chalcogenides, the principles used are equally applicable to most good thermoelectric materials that could enable improvement of thermoelectric devices from niche applications into the mainstream of energy technologies. PMID:23074043

Pei, Yanzhong; Wang, Heng; Snyder, G J

2012-12-01

231

Thermoelectric generator testing and RTG degradation mechanisms evaluation. Progress report No. 35  

SciTech Connect

The n-type selenide legs after 14,000 hours continue to show reasonable agreement with the 3M Co. published data. In the ingradient testing after 14,700 hours the n-legs show serious degradation in power to load. Weight loss measurements on the first samples of material produced by G.E. match the results previously obtained on R.C.A. material from the MHW program. The remaining MHW generator on test Q1-A has accumulated 22,519 hours and performance remains stable. The 18 couple modules S/N-1 and -3 previously tested at RCA show no significant change in operation during the current JPL testing. No changes in the trends of degradation of LES 8 and 9 and the Voyager RTGs have been observed.

Lockwood, A.; Shields, V.

1980-05-01

232

Program of thermoelectric generator testing and RTG degradation mechanisms evaluation. Progress report No. 38  

SciTech Connect

The n-type gadolinium selenide legs after 17,500 hours continue to show reasonable agreement with the 3M Co. published thermal conductivity data. Weight loss for both coated and uncoated Si-Ge material produced by G.E. are reported. No significant discrepancies with the results previously obtained on R.C.A. material from the MHW program have been found. Thermal conductivity measurements are also in agreement. The remaining MHW generator on test, Q1-A, has accumulated 26,800 hours and performance remains stable. The performance of the 18 couple modules S/N-1, S/N-2, and S/N-3 to date is summarized. Telemetry data indicate no changes in the trends of degradation of LES 8 and 9 and the Voyager RTGs.

Lockwood, A.; Shields, V.

1980-11-01

233

Thermoelectric generator testing and RTG degradation mechanisms evaluation. Progress report No. 37  

SciTech Connect

The n-type selenide legs after 16,500 hours continue to show reasonable agreement with the 3M Co. published thermal conductivity data. In the ingradient testing after 17,000 hours the 3 surviving n-legs (out of 5) show serious degradation in power to load. Small scale ratcheting has been observed on the four p-legs but no large scale effects. Weight loss for both coated and uncoated material produced by G.E. are reported. No significant discrepancies with the results previously obtained on R.C.A. material from the MHW program have been found. Thermal conductivity measurements are also in agreement. The remaining MHW generator on test, Q1-A, has accumulated 25,600 hours and performance remains stable. The 18 couple modules S/N-1 and -3 previously tested at RCA show no significant change in operation during the current JPL testing. No changes in the trends of degradation of LES 8 and 9 and the Voyager RTGs have been observed.

Lockwood, A.; Shields, V.

1980-09-01

234

Compact Thermoelectric Converter Systems Technology.  

National Technical Information Service (NTIS)

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 conducto...

1973-01-01

235

Materials for thermoelectric energy conversion  

NASA Technical Reports Server (NTRS)

The field of thermoelectric energy conversion is reviewed from both a theoretical and an experimental standpoint. The basic theory is introduced and the thermodynamic and solid state views are compared. An overview of the development of thermoelectric materials is presented with particular emphasis being placed on the most recent developments in high-temperature semiconductors. A number of possible device applications are discussed and the successful use and suitability of these devices for space power is manifest.

Wood, C.

1988-01-01

236

Thermionic Energy Conversion (TEC) topping thermoelectrics  

NASA Technical Reports Server (NTRS)

Performance expectations for thermionic and thermoelectric energy conversion systems are reviewed. It is noted that internal radiation effects diminish thermoelectric figures of merit significantly at 1000 K and substantially at 2000 K; the effective thermal conductivity contribution of intrathermoelectric radiative dissipation increases with the third power of temperature. It is argued that a consideration of thermoelectric power generation with high temperature heat sources should include utilization of thermionic energy conversion (TEC) topping thermoelectrics. However TEC alone or TEC topping more efficient conversion systems like steam or gas turbines, combined cycles, or Stirling engines would be more desirable generally.

Morris, J. F.

1981-01-01

237

Development of bismuth tellurium selenide nanoparticles for thermoelectric applications via a chemical synthetic process  

SciTech Connect

Research highlights: {yields} We synthesized a Bi{sub 2}Te{sub y}Se{sub 3-y} nano-compound via a chemical synthetic process. {yields} The compound was sintered to achieve an average grain size of about 300 nm. {yields} The resulting sintered body showed very low thermal conductivity. It is likely caused by the vigorous phonon scattering of the nano-sized grains. -- Abstract: Bismuth tellurium selenide (Bi{sub 2}Te{sub y}Se{sub 3-y}) nanoparticles for thermoelectric applications are successfully prepared via a water-based chemical reaction under atmospheric conditions. The nanostructured compound is prepared using a complexing agent (ethylenediaminetetraacetic acid) and a reducing agent (ascorbic acid) to stabilize the bismuth precursor (Bi(NO{sub 3}){sub 3}) in water and to favor the reaction with reduced sources of tellurium and selenium. The resulting powder is smaller than ca. 100 nm and has a crystalline structure corresponding to the rhombohedral Bi{sub 2}Te{sub 2.7}Se{sub 0.3}. The nanocrystalline powder is sintered via a spark plasma sintering process to obtain a sintered body composed of nano-sized grains. Important transport properties of the sintered body are measured to calculate its most important characteristic, the thermoelectric performance. The results demonstrate a relationship between the nanostructure of the sintered body and its thermal conductivity.

Kim, Cham [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of) [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of); Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Pohang 790-784 (Korea, Republic of); Kim, Dong Hwan; Han, Yoon Soo [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of)] [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of); Chung, Jong Shik [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Pohang 790-784 (Korea, Republic of)] [Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), San 31 Hyoja-dong, Pohang 790-784 (Korea, Republic of); Park, SangHa [Daegu Machinery Institute of Components and Materials (DMI), 12 Horim-dong, Dalseo-gu, Daegu 704-240 (Korea, Republic of)] [Daegu Machinery Institute of Components and Materials (DMI), 12 Horim-dong, Dalseo-gu, Daegu 704-240 (Korea, Republic of); Park, Soonheum [Department of Nanomaterial Chemistry, Dongguk University, Seokjang-dong, Gyeongju, Gyeongbuk 780-714 (Korea, Republic of)] [Department of Nanomaterial Chemistry, Dongguk University, Seokjang-dong, Gyeongju, Gyeongbuk 780-714 (Korea, Republic of); Kim, Hoyoung, E-mail: hoykim@dgist.ac.kr [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of)] [Daegu Gyeongbuk Institute of Science and Technology (DGIST), 711-623 Hosan-dong, Dalseo-gu, Daegu 704-230 (Korea, Republic of)

2011-03-15

238

Thermoelectric power generator module of 16x16 Bi{sub 2}Te{sub 3} and 0.6%ErAs:(InGaAs){sub 1-x}(InAlAs){sub x} segmented elements  

SciTech Connect

We report the fabrication and characterization of thermoelectric power generator modules of 16x16 segmented elements consisting of 0.8 mm thick Bi{sub 2}Te{sub 3} and 50 {mu}m thick ErAs:(InGaAs){sub 1-x}(InAlAs){sub x} with 0.6% ErAs by volume. An output power up to 6.3 W was measured when the heat source temperature was at 610 K. The thermoelectric properties of (InGaAs){sub 1-x}(InAlAs){sub x} were characterized from 300 up to 830 K. The finite element modeling shows that the performance of the generator modules can further be enhanced by improving the thermoelectric properties of the element materials, and reducing the electrical and thermal parasitic losses.

Zeng Gehong; Bahk, Je-Hyeong; Bowers, John E. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); Lu Hong; Gossard, Arthur C. [Department of Materials, University of California, Santa Barbara, California 93106 (United States); Singer, Suzanne L.; Majumdar, Arun [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States); Bian, Zhixi; Zebarjadi, Mona; Shakouri, Ali [Department of Electrical Engineering, University of California, Santa Cruz, California 95064 (United States)

2009-08-24

239

Oxygen Generation Assembly Technology Development  

NASA Technical Reports Server (NTRS)

Hamilton Standard Space Systems International (HSSI) is under contract to NASA Marshall Space Flight Center (MSFC) to develop an Oxygen Generation Assembly (OGA) for the International Space Station (ISS). The International Space Station Oxygen Generation Assembly (OGA) electrolyzes potable water from the Water Recovery System (WRS) to provide gaseous oxygen to the Space Station module atmosphere. The OGA produces oxygen for metabolic consumption by crew and biological specimens. The OGA also replenishes oxygen lost by experiment ingestion, airlock depressurization, CO2 venting, and leakage. As a byproduct, gaseous hydrogen is generated. The hydrogen will be supplied at a specified pressure range above ambient to support future utilization. Initially, the hydrogen will be vented overboard to space vacuum. This paper describes the OGA integration into the ISS Node 3. It details the development history supporting the design and describes the OGA System characteristics and its physical layout.

Bagdigian, Robert; Cloud, Dale

1999-01-01

240

34th Intersociety Energy Conversion Engineering Conference p. 2567 (1999) A New High Efficiency Segmented Thermoelectric  

E-print Network

Segmented Thermoelectric Unicouple T. Caillat, J.- P. Fleurial, G. J. Snyder, A. Zoltan, D. Zoltan, and A to operate thermoelectric generator devices over large temperature gradients and also to maximize the thermoelectric performance of the materials used to build the devices. However, no single thermoelectric material

241

Fabrication of Lanthanum Telluride 14-1-11 Zintl High-Temperature Thermoelectric Couple  

NASA Technical Reports Server (NTRS)

The development of more efficient thermoelectric couple technology capable of operating with high-grade heat sources up to 1,275 K is key to improving the performance of radioisotope thermoelectric generators. Lanthanum telluride La3-xTe4 and 14-1-11 Zintls (Yb14MnSb11) have been identified as very promising materials. The fabrication of advanced high-temperature thermoelectric couples requires the joining of several dissimilar materials, typically including a number of diffusion bonding and brazing steps, to achieve a device capable of operating at elevated temperatures across a large temperature differential (up to 900 K). A thermoelectric couple typically comprises a heat collector/ exchanger, metallic interconnects on both hot and cold sides, n-type and ptype conductivity thermoelectric elements, and cold-side hardware to connect to the cold-side heat rejection and provide electrical connections. Differences in the physical, mechanical, and chemical properties of the materials that make up the thermoelectric couple, especially differences in the coefficients of thermal expansion (CTE), result in undesirable interfacial stresses that can lead to mechanical failure of the device. The problem is further complicated by the fact that the thermoelectric materials under consideration have large CTE values, are brittle, and cracks can propagate through them with minimal resistance. The inherent challenge of bonding brittle, high-thermal-expansion thermoelectric materials to a hot shoe material that is thick enough to carry the requisite electrical current was overcome. A critical advantage over prior art is that this device was constructed using all diffusion bonds and a minimum number of assembly steps. The fabrication process and the materials used are described in the following steps: (1) Applying a thin refractory metal foil to both sides of lanthanum telluride. To fabricate the n-type leg of the advanced thermoelectric couple, the pre-synthesized lanthanum telluride coupon was diffusion bonded to the metal foil using a thin adhesion layer. (2) Repeating a similar process for the 14-1-11 Zintl p-type leg of the advanced thermoelectric couple. (3) Bonding thick CTE-matched metal plates on the metallized lanthanum telluride and Yb14MnSb11 to form the hot and cold sides of the thermoelectric couple. The calculated conversion efficiency of such an advanced couple would be about 10.5 percent, about 35 percent better than heritage radioisotope thermoelectric technology that relies on Si-Ge alloys. In addition, unlike Si-Ge alloys, these materials can be combined with many other thermoelectric materials optimized for operation at lower temperatures to achieve conversion efficiency in excess of 15 percent (a factor of 2 increase over heritage technology).

Ravi, Vilupanur A.; Li, Billy Chun-Yip; Fleurial, Pierre; Star, Kurt

2010-01-01

242

An Innovative System for the Efficient and Effective Treatment of Non-Traditional Waters for Reuse in Thermoelectric Power Generation  

SciTech Connect

This study assessed opportunities for improving water quality associated with coal-fired power generation including the use of non-traditional waters for cooling, innovative technology for recovering and reusing water within power plants, novel approaches for the removal of trace inorganic compounds from ash pond effluents, and novel approaches for removing biocides from cooling tower blowdown. This research evaluated specifically designed pilot-scale constructed wetland systems for treatment of targeted constituents in non-traditional waters for reuse in thermoelectric power generation and other purposes. The overall objective of this project was to decrease targeted constituents in non-traditional waters to achieve reuse criteria or discharge limitations established by the National Pollutant Discharge Elimination System (NPDES) and Clean Water Act (CWA). The six original project objectives were completed, and results are presented in this final technical report. These objectives included identification of targeted constituents for treatment in four non-traditional water sources, determination of reuse or discharge criteria for treatment, design of constructed wetland treatment systems for these non-traditional waters, and measurement of treatment of targeted constituents in non-traditional waters, as well as determination of the suitability of the treated non-traditional waters for reuse or discharge to receiving aquatic systems. The four non-traditional waters used to accomplish these objectives were ash basin water, cooling water, flue gas desulfurization (FGD) water, and produced water. The contaminants of concern identified in ash basin waters were arsenic, chromium, copper, mercury, selenium, and zinc. Contaminants of concern in cooling waters included free oxidants (chlorine, bromine, and peroxides), copper, lead, zinc, pH, and total dissolved solids. FGD waters contained contaminants of concern including arsenic, boron, chlorides, selenium, mercury, chemical oxygen demand (COD), and zinc. Similar to FGD waters, produced waters contained contaminants of concern that are predominantly inorganic (arsenic, cadmium, chlorides, chromium, copper, lead, mercury, nickel, sulfide, zinc, total dissolved solids), but also contained some organics (benzene, PAHs, toluene, total organic carbon, total suspended solids, and oil and grease). Constituents of concern that may cause chemical scaling, biofouling and corrosion, such as pH, hardness and ionic strength, and nutrients (P, K, and N) may also be found in all four non-traditional waters. NPDES permits were obtained for these non-traditional waters and these permit limits are summarized in tabular format within this report. These limits were used to establish treatment goals for this research along with toxicity values for Ceriodaphnia dubia, water quality criteria established by the US EPA, irrigation standards established by the United States Department of Agriculture (USDA), and reuse standards focused on minimization of damage to the power plant by treated waters. Constructed wetland treatment systems were designed for each non-traditional water source based on published literature reviews regarding remediation of the constituents of concern, biogeochemistry of the specific contaminants, and previous research. During this study, 4 non-traditional waters, which included ash basin water, cooling water, FGD water and produced water (PW) were obtained or simulated to measure constructed wetland treatment system performance. Based on data collected from FGD experiments, pilot-scale constructed wetland treatment systems can decrease aqueous concentrations of elements of concern (As, B, Hg, N, and Se). Percent removal was specific for each element, including ranges of 40.1% to 77.7% for As, 77.6% to 97.8% for Hg, 43.9% to 88.8% for N, and no measureable removal to 84.6% for Se. Other constituents of interest in final outflow samples should have aqueous characteristics sufficient for discharge, with the exception of chlorides (<2000 mg/L). Based on total dissolved solids, co-

John Rodgers; James Castle

2008-08-31

243

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)

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.

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

2012-06-01

244

Lunar Base Thermoelectric Power Station Study  

NASA Astrophysics Data System (ADS)

Under NASA's Project Prometheus, the Nuclear Space Power Systems Program, the Jet Propulsion Laboratory, Pratt & Whitney Rocketdyne, and Teledyne Energy Systems have teamed with a number of universities, under the Segmented Thermoelectric Multicouple Converter (STMC) Task, to develop the next generation of advanced thermoelectric converters for space reactor power systems. Work on the STMC converter assembly has progressed to the point where the lower temperature stage of the segmented multicouple converter assembly is ready for laboratory testing, and promising candidates for the upper stage materials have been identified and their properties are being characterized. One aspect of the program involves mission application studies to help define the potential benefits from the use of these STMC technologies for designated NASA missions such as a lunar base power station where kilowatts of power would be required to maintain a permanent manned presence on the surface of the moon. A modular 50 kWe thermoelectric power station concept was developed to address a specific set of requirements developed for this particular mission concept. Previous lunar lander concepts had proposed the use of lunar regolith as in-situ radiation shielding material for a reactor power station with a one kilometer exclusion zone radius to minimize astronaut radiation dose rate levels. In the present concept, we will examine the benefits and requirements for a hermetically-sealed reactor thermoelectric power station module suspended within a man-made lunar surface cavity. The concept appears to maximize the shielding capabilities of the lunar regolith while minimizing its handling requirements. Both thermal and nuclear radiation levels from operation of the station, at its 100-m exclusion zone radius, were evaluated and found to be acceptable. Site preparation activities are reviewed as well as transport issues for this concept. The goal of the study was to review the entire life cycle of the unit to assess its technical problems and technology needs in all areas to support the development, deployment, operation and disposal of the unit.

Determan, William; Frye, Patrick; Mondt, Jack; Fleurial, Jean-Pierre; Johnson, Ken; Stapfer, Gerhard; Brooks, Michael; Heshmatpour, Ben

2006-01-01

245

Lunar base thermoelectric power station study  

NASA Technical Reports Server (NTRS)

Under NASA's Project Prometheus, the Nuclear Systems Program, the Jet Propulsion Laboratory, Pratt & Whitney Rocketdyne, and Teledyne Energy Systems have teamed with a number of universities, under the Segmented Thermoelectric Multicouple Converter (STMC) program, to develop the next generation of advanced thermoelectric converters for space reactor power systems. Work on the STMC converter assembly has progressed to the point where the lower temperature stage of the segmented multicouple converter assembly is ready for laboratory testing and the upper stage materials have been identified and their properties are being characterized. One aspect of the program involves mission application studies to help define the potential benefits from the use of these STMC technologies for designated NASA missions such as the lunar base power station where kilowatts of power are required to maintain a permanent manned presence on the surface of the moon. A modular 50 kWe thermoelectric power station concept was developed to address a specific set of requirements developed for this mission. Previous lunar lander concepts had proposed the use of lunar regolith as in-situ radiation shielding material for a reactor power station with a one kilometer exclusion zone radius to minimize astronaut radiation dose rate levels. In the present concept, we will examine the benefits and requirements for a hermetically-sealed reactor thermoelectric power station module suspended within a man-made lunar surface cavity. The concept appears to maximize the shielding capabilities of the lunar regolith while minimizing its handling requirements. Both thermal and nuclear radiation levels from operation of the station, at its 100-m exclusion zone radius, were evaluated and found to be acceptable. Site preparation activities are reviewed and well as transport issues for this concept. The goal of the study was to review the entire life cycle of the unit to assess its technical problems and technology needs in all areas to support the development, deployment, operation and disposal of the unit.

Determan, William; Frye, Patrick; Mondt, Jack; Fleurial, Jean-Pierre; Johnson, Ken; Stapfer, G.; Brooks, Michael D.; Heshmatpour, Ben

2006-01-01

246

CEC-500-2010-FS-018 Automotive Thermoelectric  

E-print Network

CEC-500-2010-FS-018 Automotive Thermoelectric HVAC Development and Demonstration Project thermoelectric cooling would significantly reduce the demand for petroleum and provide a clean alternative will develop and demonstrate an operational and economically-viable thermoelectric Heating Ventilation and Air

247

Multistage thermoelectric micro coolers  

Microsoft Academic Search

Multistage thermoelectric coolers have been used for a long time because they offer a larger temperature difference than single stage thermoelectric coolers. MEMS technology leads to the possibility to fabricate multistage thermoelectric micro coolers in batches without much increase in complexity compared to single stage cooler fabrication. In this paper, we discuss the design of multistage thermoelectric coolers to optimize

Ronggui Yang; C. Gang; G. J. Snyder; J.-P. Fleurial

2002-01-01

248

Applied Mathematical Sciences, Vol. 4, 2010, no. 11, 505 -514 Efficiency of Inhomogeneous Thermoelectric  

E-print Network

Thermoelectric Generators Hong Zhou Department of Applied Mathematics Naval Postgraduate School, Monterey, CA thermoelectric generators. The effects of different physical parameters on the efficiency of a generator of a thermoelectric generator is insensitive to both the electrical resistivity and thermal conductivity. However

Zhou, Hong

249

Nanostructured Thermoelectric Materials: From Superlattices to Nanocomposites Ronggui Yang1  

E-print Network

Nanostructured Thermoelectric Materials: From Superlattices to Nanocomposites Ronggui Yang1 conductivity led to a large increase in the thermoelectric figure of merit in several superlattice systems. Materials with a large thermoelectric figure of merit can be used to develop efficient solid-state devices

Chen, Gang

250

Update to the safety program for the general-purpose heat source radioisotope thermoelectric generators for the Galileo and Ulysses missions  

NASA Technical Reports Server (NTRS)

With the rescheduling of the Galileo and Ulysses launches and the use of new upper stages following the Challenger accident, the aerospace nuclear safety program for the general-purpose heat source radioisotope thermoelectric generators (GPHS-RTGs) was extended to accommodate the new mission scenarios. As in the original safety program, the objectives were to determine the response of the GPHS-RTG to the various postulated accident environments and to determine the risk (if any) associated with these postulated accidents. The extended GPHS-RTG safety program was successfully completed in sufficient time to prepare an updated Final Safety Analysis Report (FSAR) with revisions for the October 1989 launch of the Galileo spacecraft.

Bennett, Gary L.; Bradshaw, C. T.; Englehart, Richard W.; Bartram, Bart W.; Cull, Theresa A.; Zocher, Roy W.; Eck, Marshall B.; Mukunda, Meera; Brenza, Peter T.; Chan, Chris C.

1992-01-01

251

Life Testing of Yb14MnSb11 for High Performance Thermoelectric Couples  

NASA Technical Reports Server (NTRS)

The goal of this study is to verify the long term stability of Yb14MnSb11 for high performance thermoelectric (TE) couples. Three main requirements need to be satisfied to ensure the long term stability of thermoelectric couples: 1) stable thermoelectric properties, 2) stable bonding interfaces, and 3) adequate sublimation suppression. The efficiency of the couple is primarily based on the thermoelectric properties of the materials selected for the couple. Therefore, these TE properties should exhibit minimal degradation during the operating period of the thermoelectric couples. The stability of the bonding is quantified by low contact resistances of the couple interfaces. In order to ensure high efficiency, the contact resistances of the bonding interfaces should be negligible. Sublimation suppression is important because the majority of thermoelectric materials used for power generation have peak figures of merit at temperatures where sublimation rates are high. Controlling sublimation is also essential to preserve the efficiency of the couple. During the course of this research, three different life tests were performed with Yb14MnSb11 coupons. TE properties of Yb14MnSb11 exhibited no degradation after 6 months of aging at 1273K, and the electrical contact resistance between a thin metallization layer and the Yb14MnSb11 remained negligible after 1500hr aging at 1273K. A sublimation suppression layer for Yb14MnSb11 was developed and demonstrated for more than 18 months with coupon testing at 1273K. These life test data indicate that thermoelectric elements based on Yb14MnSb11 are a promising technology for use in future high performance thermoelectric power generating couples.

Paik, Jong-Ah; Brandon, Erik; Caillat, Thierry; Ewell, Richard; Fleurial, Jean-Pierre

2011-01-01

252

A study of nanoscale thermoelectric oxides: From fabrication to characterization  

NASA Astrophysics Data System (ADS)

Around 90% of the energy human beings used is generated by heat engines with typical efficiencies of 30˜40%. This means over 400 EJ (4e20 J) heat is dissipated into the environment every year. Thermoelectric materials, which can offer the most straightforward conversion between thermal and electrical energy is an ideal candidate to harvest these unclaimed energy. The primary bottleneck of the wide application of thermoelectric materials is their relatively low conversion efficiency. Previous research shows their convert efficiency can be improved by reducing their dimension to nanoscale. Thermoelectric oxides are promising candidates for the applicable nanoscale thermoelectric materials because they do not have the oxidization problem which troubles traditional thermoelectric materials in nanoscale. In this work, the benefit of reducing the size of thermoelectric oxides is studied, particularly the changing of Seebeck coefficient and the thermal conductivity of the thermoelectric oxides when their size are reduced to nanoscale. Firstly, the fabrication process of La0.95Sr0.05CoO 3 thermoelectric oxide nanofilm and nanofibers were developed. The fabricated samples were verified by XRD and SEM. Then a special MEMS device was developed and used to measure the Seebeck coefficient of the prepared nanofilm and nanofiber. The measured results are 350 microV/K and 650 microV/K respectively, which proved the potential of increasing the Seebeck coefficient of thermoelectric oxides by reducing their size to nanoscale. In order to measure the thermal conductivity of these thermoelectric oxide nanostructures, another special MEMS device was developed. The thermal conductivity of a carbon nanofiber was measured and compared with previously reported data to verify this MEMS device, and a detailed error analysis was also offered. The analysis showed that the precision of the device was in a 17˜35% range depending on different test samples. This precision is high enough for the study of thermoelectric oxides' thermal conductivities in nanoscale. Finally, a new procedure that can load the nanofibers prepared by electrospinning onto the tester was developed. La0.95Sr0.05CoO 3 nanofibers with different diameters were loaded onto the second MEMS device and their thermal conductivities were measured. The thermal conductivity of La0.95Sr0.05CoO3 nanofiber with the diameter of 105 nm was 27% of that of La0.95Sr0.05CoO3 nanofiber with the diameter of 290 nm. The decrease of the thermal conductivity of La0.95Sr0.05CoO3 nanofibers with the decrease of their diameters demonstrates that reducing the size of thermoelectric oxides to nanoscale can reduce their thermal conductivity as well.

Xu, Weihe

253

Transport Properties of Bulk Thermoelectrics An International Round-Robin Study, Part I: Seebeck Coefficient and Electrical Resistivity  

SciTech Connect

Recent research and development of high temperature thermoelectric materials has demonstrated great potential of converting automobile exhaust heat directly into electricity. Thermoelectrics based on classic bismuth telluride have also started to impact the automotive industry by enhancing air conditioning efficiency and integrated cabin climate control. In addition to engineering challenges of making reliable and efficient devices to withstand thermal and mechanical cycling, the remaining issues in thermoelectric power generation and refrigeration are mostly materials related. The figure-of-merit, ZT, still needs to improve from the current value of 1.0 - 1.5 to above 2 to be competitive to other alternative technologies. In the meantime, the thermoelectric community could greatly benefit from the development of international test standards, improved test methods and better characterization tools. Internationally, thermoelectrics have been recognized by many countries as an important area for improving energy efficiency. The International Energy Agency (IEA) group under the implementing agreement for Advanced Materials for Transportation (AMT) identified thermoelectric materials as an important area in 2009. This paper is Part I of the international round-robin testing of transport properties of bulk thermoelectrics. The main focuses in Part I are on two electronic transport properties: Seebeck coefficient and electrical resistivity.

Wang, Hsin [ORNL; Porter, Wallace D [ORNL; Bottner, Harold [Fraunhofer-Institute, Freiburg, Germany; Konig, Jan [Fraunhofer-Institute, Freiburg, Germany; Chen, Lidong [Chinese Academy of Sciences; Bai, Shengqiang [Chinese Academy of Sciences; Tritt, Terry M. [Clemson University; Mayolett, Alex [Corning, Inc; Senawiratne, Jayantha [Corning, Inc; Smith, Charlene [Corning, Inc; Harris, Fred [ZT-Plus; Gilbert, Partricia [Marlow Industries, Inc; Sharp, Jeff [Marlow Industries, Inc; Lo, Jason [CANMET - Materials Technology Laboratory, Natural Resources of Canada; Keinke, Holger [University of Waterloo, Canada; Kiss, Laszlo I. [University of Quebec at Chicoutimi

2013-01-01

254

Convergence of electronic bands for high performance bulk thermoelectrics.  

PubMed

Thermoelectric generators, which directly convert heat into electricity, have long been relegated to use in space-based or other niche applications, but are now being actively considered for a variety of practical waste heat recovery systems-such as the conversion of car exhaust heat into electricity. Although these devices can be very reliable and compact, the thermoelectric materials themselves are relatively inefficient: to facilitate widespread application, it will be desirable to identify or develop materials that have an intensive thermoelectric materials figure of merit, zT, above 1.5 (ref. 1). Many different concepts have been used in the search for new materials with high thermoelectric efficiency, such as the use of nanostructuring to reduce phonon thermal conductivity, which has led to the investigation of a variety of complex material systems. In this vein, it is well known that a high valley degeneracy (typically ?6 for known thermoelectrics) in the electronic bands is conducive to high zT, and this in turn has stimulated attempts to engineer such degeneracy by adopting low-dimensional nanostructures. Here we demonstrate that it is possible to direct the convergence of many valleys in a bulk material by tuning the doping and composition. By this route, we achieve a convergence of at least 12 valleys in doped PbTe(1-x)Se(x) alloys, leading to an extraordinary zT value of 1.8 at about 850 kelvin. Band engineering to converge the valence (or conduction) bands to achieve high valley degeneracy should be a general strategy in the search for and improvement of bulk thermoelectric materials, because it simultaneously leads to a high Seebeck coefficient and high electrical conductivity. PMID:21544143

Pei, Yanzhong; Shi, Xiaoya; LaLonde, Aaron; Wang, Heng; Chen, Lidong; Snyder, G Jeffrey

2011-05-01

255

Theory of the Thermoelectric Power of Semiconductors  

Microsoft Academic Search

The usual theory of thermoelectric power fails to account for the marked rise in this quantity which has been found recently for some semiconductors as the temperature is lowered below room temperature. This paper develops the recently suggested explanation that the thermoelectric power Q is the sum of the usual electronic term Qe, resulting from the spontaneous tendency of the

Conyers Herring

1954-01-01

256

A design method of thermoelectric cooler  

Microsoft Academic Search

A system design method of thermoelectric cooler is developed in the present study. The design calculation utilizes the performance curve of the thermoelectric module that is determined experimentally. An automatic test apparatus was designed and built to illustrate the testing. The performance test results of the module are used to determine the physical properties and derive an empirical relation for

B. J Huang; C. J Chin; C. L Duang

2000-01-01

257

Heat Transfer in Thermoelectric Materials and Devices  

E-print Network

Solid-state thermoelectric devices are currently used in applications ranging from thermocouple sensors to power generators in space missions, to portable air-conditioners and refrigerators. With the ever-rising demand ...

Tian, Zhiting

258

Review of nanostructured devices for thermoelectric applications  

PubMed Central

Summary A big research effort is currently dedicated to the development of thermoelectric devices capable of a direct thermal-to-electrical energy conversion, aiming at efficiencies as high as possible. These devices are very attractive for many applications in the fields of energy recovery and green energy harvesting. In this paper, after a quick summary of the fundamental principles of thermoelectricity, the main characteristics of materials needed for high efficiency thermoelectric conversion will be discussed, and a quick review of the most promising materials currently under development will be given. This review paper will put a particular emphasis on nanostructured silicon, which represents a valid compromise between good thermoelectric properties on one side and material availability, sustainability, technological feasibility on the other side. The most important bottom-up and top-down nanofabrication techniques for large area silicon nanowire arrays, to be used for high efficiency thermoelectric devices, will be presented and discussed. PMID:25247111

2014-01-01

259

Development of Advanced Stirling Radioisotope Generator for Space Exploration  

NASA Astrophysics Data System (ADS)

Under the joint sponsorship of the Department of Energy and NASA, a radioisotope power system utilizing Stirling power conversion technology is being developed for potential future space missions. The higher conversion efficiency of the Stirling cycle compared with that of Radioisotope Thermoelectric Generators (RTGs) used in previous missions (Viking, Pioneer, Voyager, Galileo, Ulysses, Cassini, and New Horizons) offers the advantage of a four-fold reduction in PuO2 fuel, thereby saving cost and reducing radiation exposure to support personnel. With the advancement of state-of-the-art Stirling technology development under the NASA Research Announcement (NRA) project, the Stirling Radioisotope Generator program has evolved to incorporate the advanced Stirling convertor (ASC), provided by Sunpower, into an engineering unit. Due to the reduced envelope and lighter mass of the ASC compared to the previous Stirling convertor, the specific power of the flight generator is projected to increase from 3.5 We/kg to 7 We/kg, along with a 25% reduction in generator length. Modifications are being made to the ASC design to incorporate features for thermal, mechanical, and electrical integration with the engineering unit. These include the heat collector for hot end interface, cold-side flange for waste heat removal and structural attachment, and piston position sensor for ASC control and power factor correction. A single-fault tolerant, active power factor correction controller is used to synchronize the Stirling convertors, condition the electrical power from AC to DC, and to control the ASCs to maintain operation within temperature and piston stroke limits. Development activities at Sunpower and NASA Glenn Research Center (GRC) are also being conducted on the ASC to demonstrate the capability for long life, high reliability, and flight qualification needed for use in future missions.

Chan, Jack; Wood, J. Gary; Schreiber, Jeffrey G.

2007-01-01

260

Silicon-Based Thermoelectrics: Harvesting Low Quality Heat Using Economically Printed Flexible Nanostructured Stacked Thermoelectric Junctions  

SciTech Connect

Broad Funding Opportunity Announcement Project: UIUC is experimenting with silicon-based materials to develop flexible thermoelectric devices—which convert heat into energy—that can be mass-produced at low cost. A thermoelectric device, which resembles a computer chip, creates electricity when a different temperature is applied to each of its sides. Existing commercial thermoelectric devices contain the element tellurium, which limits production levels because tellurium has become increasingly rare. UIUC is replacing this material with microscopic silicon wires that are considerably cheaper and could be equally effective. Improvements in thermoelectric device production could return enough wasted heat to add up to 23% to our current annual electricity production.

None

2010-03-01

261

Thermoelectric materials and devices  

NASA Technical Reports Server (NTRS)

New thermoelectric materials comprise highly [111]-oriented twinned group IV alloys on the basal plane of trigonal substrates, which exhibit a high thermoelectric figure of merit and good material performance, and devices made with these materials.

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor); Talcott, Noel A. (Inventor)

2011-01-01

262

Thermoelectric Temperature Control  

E-print Network

NOTE 201TM TECHNICAL Optimizing Thermoelectric Temperature Control Systems #12;2 May 1995 92-040000A © 1995 Wavelength Electronics, Inc. Thermoelectric coolers (TECs) are used in a variety understanding of thermal management techniques and carefully select the thermoelectric module, temperature

Saffman, Mark

263

Thermoelectric and Thermionic Conversion Technology  

NASA Technical Reports Server (NTRS)

Applied research and technology efforts in thermoelectric and thermionic programs were recommended that will enable space power systems for the nation's future space missions. Specifically it was argued that the effort in thermoelectric materials technology be broadened with the objective of obtaining a material with a Figure of Merit greater than 1.0 x 10(-3)/K for hot junction temperatures of 1100 to 1500 K. The recommended effort in thermionics is to pursue technology programs that will result in an understanding and lifetime prediction methodologies for fuel-emitter and sheath-insulator behavior as a function of operating time and temperature. Also it is recommended that an effort be initiated that combines the thermoelectric, thermionic and power electronic technologies into a program to develop the technology for high temperature, high radiation resistant, and high current electronic switches.

Mondt, J. F.; Ambrus, J. H.

1984-01-01

264

A thermoelectric converter for energy supply  

Microsoft Academic Search

A thermoelectric power generator in silicon technology is used for the energy supply of low power systems. An application is described generating an electrical power of 1.5 ?W with a temperature difference of 10°C. With the generated electrical power it is possible to operate a small preamplifier and a sensor control system. For complexer applications a generator with a power

H Glosch; M Ashauer; U Pfeiffer; W Lang

1999-01-01

265

Thermoelectric properties of cobalt antimonide>-based skutterudites  

Microsoft Academic Search

Solid state cooling and power generation based on thermoelectric principles are regarded as one of the technologies with the potential of solving the current energy crisis. Thermoelectric devices could be widely used in waste heat recovery, small scale power generation and refrigeration. It has no moving parts and is environmental friendly. The limitation to its application is due to its

Jian Yang

2010-01-01

266

Enhanced thermoelectric performance of rough silicon nanowires  

Microsoft Academic Search

Approximately 90 per cent of the world's power is generated by heat engines that use fossil fuel combustion as a heat source and typically operate at 30-40 per cent efficiency, such that roughly 15terawatts of heat is lost to the environment. Thermoelectric modules could potentially convert part of this low-grade waste heat to electricity. Their efficiency depends on the thermoelectric

Allon I. Hochbaum; Raul Diaz Delgado; Wenjie Liang; Erik C. Garnett; Mark Najarian; Arun Majumdar; Peidong Yang

2008-01-01

267

Stresa, Italy, 26-28 April 2006 THERMOELECTRIC AND MICROBATTERY HYBRID SYSTEM WITH ITS POWER  

E-print Network

developed. It consists in hybriding an energy storage system (thin film solid state battery change depending on the outside conditions) and required by the thin film solid state battery conversion and energy storage. A hybrid system comprising a thermoelectric generator, a thin film solid state

Paris-Sud XI, Université de

268

Thermoelectric standardisation - Reference materials and characterisation  

NASA Astrophysics Data System (ADS)

Thermoelectric materials for working temperatures between 300 K and 1000 K become continuously more important for energy recuperation applications. The efficiency is determined by the transport properties (electrical and thermal conductivity and Seebeck coefficient), which form the known thermoelectric figure of merit ZT. The thorough determination of ZT represents the basis for the assessment of thermoelectric materials research. Due to different continuing difficulties measurement errors distinctly higher than 15% can be observed repeatedly, which is still too high for an industrial benchmark and deficient for many scientific investigations and technological developments. Against this background a project was launched in 2011 together with the Fraunhofer Institute of Physical Measurement Techniques (IPM, Freiburg), the Department Temperature of the Physikalisch-Technische Bundesanstalt (PTB, Berlin) and the company Netzsch Gerätebau GbmH (Selb). The aim of the project "Thermoelectric Standardisation" (TEST) is to minimise the measurement uncertainties and to develop traceable, high-accurate thermoelectric characterisation techniques and thermoelectric reference materials for the mentioned temperature range. Here we initially present the project to the thermoelectric society and want to give a survey on the planned activities and the current status of the contributions of the German Aerospace Center (DLR, Cologne).

Ziolkowski, P.; Blaschkewitz, P.; Stiewe, C.; Karpinski, G.; Müller, E.

2012-06-01

269

Experimental Study and Optimization of Thermoelectricity-Driven Autonomous Sensors for the Chimney of a Biomass Power Plant  

NASA Astrophysics Data System (ADS)

In the work discussed in this paper a thermoelectric generator was developed to harness waste heat from the exhaust gas of a boiler in a biomass power plant and thus generate electric power to operate a flowmeter installed in the chimney, to make it autonomous. The main objective was to conduct an experimental study to optimize a previous design obtained after computational work based on a simulation model for thermoelectric generators. First, several places inside and outside the chimney were considered as sites for the thermoelectricity-driven autonomous sensor. Second, the thermoelectric generator was built and tested to assess the effect of the cold-side heat exchanger on the electric power, power consumption by the flowmeter, and transmission frequency. These tests provided the best configuration for the heat exchanger, which met the transmission requirements for different working conditions. The final design is able to transmit every second and requires neither batteries nor electric wires. It is a promising application in the field of thermoelectric generation.

Rodríguez, A.; Astrain, D.; Martínez, A.; Aranguren, P.

2014-06-01

270

Device testing and characterization of thermoelectric nanocomposites  

E-print Network

It has become evident in recent years that developing clean, sustainable energy technologies will be one of the world's greatest challenges in the 21st century. Thermoelectric materials can potentially make a contribution ...

Muto, Andrew (Andrew Jerome)

2008-01-01

271

Thermoelectric Powered Wireless Sensors for Dry-Cask Storage  

NASA Astrophysics Data System (ADS)

This study focuses on the development of self-powered wireless sensors. These sensors can be used to measure key parameters in extreme environments; e.g., temperature monitoring for spent nuclear fuel during dry-cask storage. This study has developed a design methodology for these self-powered monitoring systems. The main elements that constitute this work consist of selecting and testing a power source for the wireless sensor, determination of the attenuation of the wireless signal, and testing the wireless sensor circuitry in an extreme environment. OrigenArp determined the decay heat and gamma/neutron source strength of the spent fuel throughout the service life of the dry-cask. A first principles analysis modeled the temperatures inside the dry-cask. A finite-element heat transfer code calculated the temperature distribution of the thermoelectric and heat sink. The temperature distributions determine the power produced by the thermoelectric. It was experimentally verified that a thermoelectric generator (HZ-14) with a DC/DC converter (Linear Technology LTC3108EDE) can power a transceiver (EmbedRF) at condition which represent prototypical conditions throughout and beyond the service life of the dry-cask. The wireless sensor is required to broadcast with enough power to overcome the attenuation from the dry-cask. It will be important to minimize the attenuation of the signal in order to broadcast with a small transmission power. To investigate the signal transmission through the dry-cask, CST Microwave Studio was used to determine the scattering parameter S2,1 for a horizontal dry-cask. Important parameters that can influence the transmission of the signal are antenna orientation, antenna placement, and transmission frequency. The thermoelectric generator, DC/DC converter, and transceiver were exposed to 60Co gamma radiation (exposure rate170.3 Rad/min) at the University of Wisconsin Medical Radiation Research Center. The effects of gamma radiation on the thermoelectric voltage, DC/DC converter voltage, relative signal strength indicator, and counter number were measured and compared. The analysis estimates that a thermoelectric generator can produce enough power for a wireless sensor to function and transmit data from inside the dry-cask throughout its service life and beyond. Some of the electronics for the wireless sensor need to be properly protected to ensure it will function in an extreme environment.

Carstens, Thomas Alan

272

Estimating Thermoelectric Water Use  

NASA Astrophysics Data System (ADS)

In 2009, the Government Accountability Office recommended that the U.S. Geological Survey (USGS) and Department of Energy-Energy Information Administration, (DOE-EIA) jointly improve their thermoelectric water-use estimates. Since then, the annual mandatory reporting forms returned by powerplant operators to DOE-EIA have been revised twice to improve the water data. At the same time, the USGS began improving estimation of withdrawal and consumption. Because of the variation in amount and quality of water-use data across powerplants, the USGS adopted a hierarchy of methods for estimating water withdrawal and consumptive use for the approximately 1,300 water-using powerplants in the thermoelectric sector. About 800 of these powerplants have generation and cooling data, and the remaining 500 have generation data only, or sparse data. The preferred method is to accept DOE-EIA data following validation. This is the traditional USGS method and the best method if all operators follow best practices for measurement and reporting. However, in 2010, fewer than 200 powerplants reported thermodynamically realistic values of both withdrawal and consumption. Secondly, water use was estimated using linked heat and water budgets for the first group of 800 plants, and for some of the other 500 powerplants where data were sufficient for at least partial modeling using plant characteristics, electric generation, and fuel use. Thermodynamics, environmental conditions, and characteristics of the plant and cooling system constrain both the amount of heat discharged to the environment and the share of this heat that drives evaporation. Heat and water budgets were used to define reasonable estimates of withdrawal and consumption, including likely upper and lower thermodynamic limits. These results were used to validate the reported values at the 800 plants with water-use data, and reported values were replaced by budget estimates at most of these plants. Thirdly, at plants without valid reported water use or sufficient information to construct linked heat and water budgets, water use was estimated from net generation using average values of withdrawal and consumption per megawatt-hour (MWh). Plants with valid reported data or complete budgets were grouped by their mix of generation types and cooling types. Generation-weighted averages were calculated for each group. Because of the large variation in cooling systems, these coefficient-based estimates are imprecise at individual plants. Other investigators have derived very different coefficients for these groups, probably because they censored the data differently. Variable powerplant characteristics create a wide range in both withdrawal and consumption, even at superficially similar plants. Neither statistical estimates nor budget estimates provide precise values of water use at individual plants. Most thermoelectric water use is withdrawal for once-through cooling, and withdrawal per MWh is determined by a balance between economic and environmental concerns, constrained within very broad limits by thermodynamics. Therefore, only accurate measurement and reporting of water use has the potential to determine thermoelectric water use at watershed and local scales.

Hutson, S. S.

2012-12-01

273

Leadership Development Programs and Generational Differences.  

E-print Network

??This study examines differences and similarities across distinct generational groups in order to understand the components and delivery methods of effective leadership development programs. 159… (more)

Smolter, Valerie

2011-01-01

274

Maximum cooling temperature and uniform efficiency criterion for inhomogeneous thermoelectric materials  

E-print Network

as that in the power generation.9 However, the global opti- mization of thermoelectric cooling is even more difficultMaximum cooling temperature and uniform efficiency criterion for inhomogeneous thermoelectric cooling temperature of a uniform thermoelectric material is limited by its dimensionless figure of merit

Wang, Hongyun

275

Thin-film thermoelectric devices with high room-temperature figures of merit  

Microsoft Academic Search

Thermoelectric materials are of interest for applications as heat pumps and power generators. The performance of thermoelectric devices is quantified by a figure of merit, ZT, where Z is a measure of a material's thermoelectric properties and T is the absolute temperature. A material with a figure of merit of around unity was first reported over four decades ago, but

Rama Venkatasubramanian; Edward Siivola; Thomas Colpitts; Brooks O'Quinn

2001-01-01

276

Studying Thermoelectric Oxides using High-Resolution Scanning Transmission Electron Figure 4: a) Atomic resolution Z-  

E-print Network

Studying Thermoelectric Oxides using High-Resolution Scanning Transmission Electron Microscopy 0 the environmental impact, and deliver energy continuously, such as thermo-electric power generation, have often been overlooked. Thermo-electric (TE) power applications offer a potentially cheap, pollution- and maintenance

Ben-Arie, Jezekiel

277

www.ceramics.org | American Ceramic Society Bulletin, Vol. 91, No. 334 thermoelectric  

E-print Network

www.ceramics.org | American Ceramic Society Bulletin, Vol. 91, No. 334 Modeling thermoelectric. Thermoelectric devices have the advantage of containing no moving parts, making them quiet, durable and reliable that thermoelectric devic- es can compete with traditional refrigeration and power generation technologies.1

McGaughey, Alan

278

Stirling Convertor Technologies Being Developed for a Stirling Radioisotope Generator  

NASA Technical Reports Server (NTRS)

The Department of Energy, Lockheed Martin, Stirling Technology Company (STC), and the NASA Glenn Research Center are developing a high-efficiency Stirling Radioisotope Generator (SRG) for NASA space science missions. The SRG is being developed for multimission use, including providing electric power for unmanned Mars rovers and deep space missions. On Mars, rovers with SRGs would be used for missions that might not be able to use photovoltaic power systems, such as exploration at high Martian latitudes and missions of long duration. The projected SRG system efficiency of 23 percent will reduce the required amount of radioisotope by a factor of 4 or more in comparison to currently used Radioisotope Thermoelectric Generators. The Department of Energy recently named Lockheed Martin as the system integration contractor. Lockheed Martin has begun to develop the SRG engineering unit under contract to the Department of Energy, and has contract options to develop the qualification unit and the first flight units. The developers expect the SRG to produce about 114 Wdc at the beginning of mission, using two opposed Stirling convertors and two General Purpose Heat Source modules. STC previously developed the Stirling convertor under contract to the Department of Energy and is now providing further development as a subcontractor to Lockheed Martin. Glenn is conducting an in-house technology project to assist in developing the convertor for space qualification and mission implementation. A key milestone was recently reached with the accumulation of 12 000 hr of long-term aging on two types of neodymium-iron boron permanent magnets. These tests are characterizing any possible aging in the strength or demagnetization resistance of the magnets used in the linear alternator. Preparations are underway for a thermal/vacuum system demonstration and unattended operation during endurance testing of the 55-We Technology Demonstration Convertors. In addition, Glenn is developing a charging system for the convertors to ensure clean fills of the helium working fluid and to monitor levels of any possible contaminants at different test intervals. Possible oxidation effects depend on the level of any oxygen contamination-regenerator materials and displacer radiation shields are now being evaluated for possible oxidation effects.

Thieme, Lanny G.

2003-01-01

279

Development of improved thermoelectric materials for space nuclear power systems. Sixth technical progress report, March 1985  

SciTech Connect

The program consists of two main tasks encompassing (1) the development of an improved SiGe alloy and (2) the development of an as yet unspecified advanced material intended to have superior performance characteristics when compared to SiGe alloys. Significant progress was made toward the goal of producing a SiGe based material with an improved figure-of-merit during this reporting period. In these studies, a quantitative evaluation of the characteristics which produce the low thermal conductivities observed in SiGe alloys is being developed. Specific areas of emphasis include the effects of grain size, charge carrier and GaP concentrations. An alternate method for alloying with GaP was evaluated in which the GaP was added to SiGe during the melting operation.

Not Available

1985-01-01

280

Construction of a High Temperature Teg Measurement System for the Evaluation of Thermoelectric Oxide Modules  

NASA Astrophysics Data System (ADS)

A dedicated test stand was developed and built to characterize the efficiency, power output and open circuit voltage of various thermoelectric generators (TEGs) based on tellurides, heusler compounds and thermoelectric oxides. The test stand allows measurements of TEGs of sizes up to 4 cm × 4 cm at hot side temperatures up to 1150 K in different atmospheres. Special care was taken about the heat flux measurement by precise measurement of the temperature distribution within the reference block. In order to demonstrate the functionality of the test stand thermoelectric oxide modules (TOM) were built from n-type perovskite-type manganates and p-type cuprates. The modules were tested regarding their stability, maximum power output and efficiency at temperatures up to 1100 K. The TOMs withstand large temperature gradients and operated in ambient air yielding high power densities.

Populoh, S.; Trottmann, M.; Brunko, O. C.; Thiel, P.; Weidenkaff, A.

2013-10-01

281

Thermoelectric microdevice fabricated by a MEMS-like electrochemical process  

NASA Technical Reports Server (NTRS)

Microelectromechanical systems (MEMS) are the basis of many rapidly growing technologies, because they combine miniature sensors and actuators with communications and electronics at low cost. Commercial MEMS fabrication processes are limited to silicon-based materials or two-dimensional structures. Here we show an inexpensive, electrochemical technique to build MEMS-like structures that contain several different metals and semiconductors with three-dimensional bridging structures. We demonstrate this technique by building a working microthermoelectric device. Using repeated exposure and development of multiple photoresist layers, several different metals and thermoelectric materials are fabricated in a three-dimensional structure. A device containing 126 n-type and p-type (Bi, Sb)2Te3 thermoelectric elements, 20 microm tall and 60 microm in diameter with bridging metal interconnects, was fabricated and cooling demonstrated. Such a device should be of technological importance for precise thermal control when operating as a cooler, and for portable power when operating as a micro power generator.

Snyder, G. Jeffrey; Lim, James R.; Huang, Chen-Kuo; Fleurial, Jean-Pierre

2003-01-01

282

Thermoelectric recovery of waste heat-case studies  

Microsoft Academic Search

The use of waste heat as an energy source for thermoelectric generation largely removes the constraint for the wide scale application of this technology imposed by its relatively low conversion efficiency (typically about 5%). Paradoxically, in some parasitic applications, a low conversion efficiency can be viewed as a distinct advantage. However, commercially available thermoelectric modules are designed primarily for refrigerating

M. D. Rowe; Gao Min; S. G. K. Williams; A. Aoune; K. Matsuura; V. L. Kuznetsov; Li Wen Fu

1997-01-01

283

Physical, Mechanical, and Structural Properties of Highly Efficient Nanostructured n- and p-Silicides for Practical Thermoelectric Applications  

NASA Astrophysics Data System (ADS)

Cost-effective highly efficient nanostructured n-type Mg2Si1- x Sn x and p-type higher manganese silicide (HMS) compositions were prepared for the development of practical waste heat generators for automotive and marine thermoelectric applications, in the frame of the European Commission (EC)-funded PowerDriver project. The physical, mechanical, and structural properties were fully characterized as part of a database-generation exercise required for the thermoelectric converter design. A combination of high maximal ZT values of ˜0.6 and ˜1.1 for the HMS and Mg2Si1- x Sn x compositions, respectively, and adequate mechanical properties was obtained.

Gelbstein, Yaniv; Tunbridge, Jonathan; Dixon, Richard; Reece, Mike J.; Ning, Huanpo; Gilchrist, Robert; Summers, Richard; Agote, Iñigo; Lagos, Miguel A.; Simpson, Kevin; Rouaud, Cedric; Feulner, Peter; Rivera, Sergio; Torrecillas, Ramon; Husband, Mark; Crossley, Julian; Robinson, Ivan

2014-06-01

284

Development of a Thermal Conductivity Measurement System Using the 3 ? Method and Application to Thermoelectric Particles  

NASA Astrophysics Data System (ADS)

For this study, we developed a thermal conductivity, ?, measurement system using 3 ? method. We checked the system accuracy by measuring ? for a glass substrate (1737; Corning). Conventional evaporated aluminum wire and ink-jet printed silver wire were used as sensor wires. The system realized a ? measurement of glass within 10 % error. We estimated ? of aggregated p-type (Bi1- x Sb x )2Te3 particles using a two heat flow model. The estimated thermal conductivity of the sample ? sample are 0.06-0.27 WK-1 m-1, which is smaller than the bulk value.

Nishino, Shunsuke; Koyano, Mikio; Suekuni, Koichiro; Ohdaira, Keisuke

2014-06-01

285

Development and Evolution of Nanostructure in Bulk Thermoelectric Pb-Te-Sb Alloys  

NASA Astrophysics Data System (ADS)

Motivated by reports of exceptionally high zT > 2 in thin film superlattices or “quantum well” materials with nanometer sized features, we have undertaken a study of composite materials with nanoscale features that promise to provide similar structures in bulk material. Nanometer scale layers of PbTe and Sb2Te3 with periodicities of 180 nm to 950 nm form when quenched eutectic PbTe-Sb2Te3 melt, crystallizing as Pb2Sb6Te11, subsequently annealed. The lamellar spacing depends on the temperature and time of the anneal. The mechanism for the development of the nanostructures is probed by examining the fraction of material transformed as a function of anneal time. Preliminary analysis of the shape factor exponent reveals that the transformation to the nanostructured lamellae bears similarities to the thickening of very large plates. The coarsening of the lamellar spacing is also examined as a function of time and temperature.

Ikeda, Teruyuki; Ravi, Vilupanur A.; Collins, Lauren A.; Haile, Sossina M.; Snyder, G. Jeffrey

2007-07-01

286

Thermoelectric single-photon detector  

NASA Astrophysics Data System (ADS)

The ability to detect a single photon is the ultimate level of sensitivity in the measurement of optical radiation. Sensors capable of detecting single photons and determining their energy have many scientific and technological applications. Kondo-enhanced Seebeck effect cryogenic detectors are based on thermoelectric heat-to-voltage conversion and voltage readout. We evaluate the prospects of CeB6 and (La,Ce)B6 hexaboride crystals for their application as a sensitive element in this type of detectors. We conclude that such detectors can register a single UV photon, have a fast count rate (up to 45 MHz) and a high spectral resolution of 0.1 eV. We calculate the electric potential generated along the thermoelectric sensor upon registering a UV single photon.

Kuzanyan, A. A.; Petrosyan, V. A.; Kuzanyan, A. S.

2012-03-01

287

Miniature Radioisotope Thermoelectric Power Cubes  

NASA Technical Reports Server (NTRS)

Cube-shaped thermoelectric devices energized by a particles from radioactive decay of Cm-244 have been proposed as long-lived sources of power. These power cubes are intended especially for incorporation into electronic circuits that must operate in dark, extremely cold locations (e.g., polar locations or deep underwater on Earth, or in deep interplanetary space). Unlike conventional radioisotope thermoelectric generators used heretofore as central power sources in some spacecraft, the proposed power cubes would be small enough (volumes would range between 0.1 and 0.2 cm3) to play the roles of batteries that are parts of, and dedicated to, individual electronic-circuit packages. Unlike electrochemical batteries, these power cubes would perform well at low temperatures. They would also last much longer: given that the half-life of Cm-244 is 18 years, a power cube could remain adequate as a power source for years, depending on the power demand in its particular application.

Patel, Jagdish U.; Fleurial, Jean-Pierre; Snyder, G. Jeffrey; Caillat, Thierry

2004-01-01

288

Development of Low-Cost Remote-Control Generators Based on BiTe Thermoelectric Modules  

NASA Astrophysics Data System (ADS)

This paper presents a new thermogenerator based on moderate-temperature (up to 175°C) BiTe modules available on the open market. Despite this handicap relative to commercial thermogenerators based on high-temperature proprietary-technology PbBi modules (up to 560°C), this new design may become economically competitive due to its innovative thermal sink. Our thermal sink is based on a free-convection water loop built with standard tubing and household hot-water radiators, leading to a more practical, modular design. So, the specific cost of about 55,000 USD/kW obtained for this 120-W prototype is improved to 33,000 USD/kW for a 1-kW unit, which represents about half the price of commercial thermogenerators. Moreover, considering recently launched BiTe modules (that withstand up to 320°C), our proposition could have an even more favorable outlook.

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

2013-07-01

289

Performance of Novel Thermoelectric Cooling Module Depending on Geometrical Factors  

NASA Astrophysics Data System (ADS)

A geometrical shape factor was investigated for optimum thermoelectric performance of a thermoelectric module using finite element analysis. The cooling power, electrical energy consumption, and coefficient of performance were analyzed using simulation with different current values passing through the thermoelectric elements for varying temperature differences between the two sides. A dramatic increase in cooling power density was obtained, since it was inversely proportional to the length of the thermoelectric legs. An artificial neural network model for each thermoelectric property was also developed using input-output relations. The models including the shape factor showed good predictive capability and agreement with simulation results. The correlation of the models was found to be 99%, and the overall prediction error was in the range of 1.5% and 1.0%, which is within acceptable limits. A thermoelectric module was produced based on the numerical results and was shown to be a promising device for use in cooling systems.

Derebasi, Naim; Eltez, Muhammed; Guldiken, Fikret; Sever, Aziz; Kallis, Klaus; Kilic, Halil; Ozmutlu, Emin N.

2014-11-01

290

Thermoelectricity in atom-sized junctions at room temperatures  

PubMed Central

Atomic and molecular junctions are an emerging class of thermoelectric materials that exploit quantum confinement effects to obtain an enhanced figure of merit. An important feature in such nanoscale systems is that the electron and heat transport become highly sensitive to the atomic configurations. Here we report the characterization of geometry-sensitive thermoelectricity in atom-sized junctions at room temperatures. We measured the electrical conductance and thermoelectric power of gold nanocontacts simultaneously down to the single atom size. We found junction conductance dependent thermoelectric voltage oscillations with period 2e2/h. We also observed quantum suppression of thermovoltage fluctuations in fully-transparent contacts. These quantum confinement effects appeared only statistically due to the geometry-sensitive nature of thermoelectricity in the atom-sized junctions. The present method can be applied to various nanomaterials including single-molecules or nanoparticles and thus may be used as a useful platform for developing low-dimensional thermoelectric building blocks. PMID:24270238

Tsutsui, Makusu; Morikawa, Takanori; Arima, Akihide; Taniguchi, Masateru

2013-01-01

291

Review of solar thermoelectric energy conversion and analysis of a two cover flat-plate solar collector  

E-print Network

The process of solar thermoelectric energy conversion was explored through a review of thermoelectric energy generation and solar collectors. Existing forms of flat plate collectors and solar concentrators were surveyed. ...

Hasan, Atiya

2007-01-01

292

Progress report No. 41 for a program of thermoelectric generator testing and RTG degradation-mechanisms evaluation  

SciTech Connect

Sublimation tests conducted on Si/sub 3/N/sub 4/ coated SiGe (78%-22%) legs and SiMo hot shoes produced by G.E. were continued during this reporting period. The present test time for the SiGe legs is 1623 hours, while that for the SiMo hot-shoes is 1028 hours. No unexpected results have been observed. G.E.'s conjecture that the coatings on the SiGe legs which we presently have on test are faulty is confirmed, as this material has displayed coating failure on all n-doped samples at 1150/sup 0/C with failures beginning to show at 1100/sup 0/C. No coating failures have been observed on the hot shoes on test. Thermal conductivity tests conducted on SiGe (78% to 22%) material were extended to over 6000 hours with excellent agreement with MHW results. Testing of the 4 couple module PR-1 has been conducted for over 2,000 hours with similar agreement with past MHW tests. Testing of the Q1-A generator is continuing. The present test time is 33,632 hours. The performance of the generator remains smooth and continuous. Testing of the S/N-1 and S/N-3 eighteen couple modules has been extended to 35,105 hours and 32,403 hours, respectively. As with the Q1-A generator, the performance of these modules remains steady and smooth. Comparisons between computer predictions and the actual performance of the RTGs aboard the Voyager I and II spacecrafts has been extended to approximately four years. The agreement with prediction, in both cases, is within 0.5 percent. The corresponding comparisons for the LES-8 and LES-9 RTGs are for over five years with the same excellent agreement.

Shields, V.

1981-09-01

293

Characterizing the thermal efficiency of thermoelectric modules  

E-print Network

An experimental setup was designed and utilized to measure the thermoelectric properties as functions of temperature of a commercially available, bismuth telluride thermoelectric module. Thermoelectric modules are solid ...

Phillips, Samuel S

2009-01-01

294

Development of Flexible Micro-Thermo-electrochemical Generators Based on Ionic Liquids  

NASA Astrophysics Data System (ADS)

The unfavourable relationship between electrical and thermal conductivity limits the choice of solid-state materials for thermoelectric generators (TEG). Among ionic liquids (IOL), it appears that a large variety of thermoelectric (TE) materials with promising high Seebeck coefficients have potential for development. Furthermore, the novel solid-on-liquid deposition technology (SOLID) allows the encapsulation of liquid TE materials to create new, highly integrated TEG devices. Following this vision, this paper studies a large number of IOLs looking at TE-relevant parameters such as thermal and electrical conductivity, Seebeck coefficient and temperature-dependent viscosity. We show that positive and negative Seebeck coefficients can be obtained, depending on the molecular structure and the viscosity of the IOL. The properties of single-junction TEGs are presented in terms of I- V characteristics correlated with the IOL properties. We prove that the limiting effect of conversion efficiency is the current density that can be extracted from a device rather than the Seebeck coefficient.

Uhl, Stefanie; Laux, Edith; Journot, Tony; Jeandupeux, Laure; Charmet, Jérôme; Keppner, Herbert

2014-10-01

295

Developments of terahertz wave generation technologies  

NASA Astrophysics Data System (ADS)

Recent developments of terahertz wave generation devices utilizing lattice and molecular vibration are introduced. They are semiconductor Raman laser and amplifier, parametric generation of terahertz wave using phonon-polaritons in semiconductors and dielectrics, together with electronic devices: TUNNETT diode and ISIT. Future important applications will be in the field of medicine, biology, and pharmacy.

Suto, Ken; Nishizawa, Jun-Ichi

2004-05-01

296

Photo-controllable thermoelectric properties with reversibility and photo-thermoelectric effects of tungsten trioxide accompanied by its photochromic phenomenon  

NASA Astrophysics Data System (ADS)

The addition of photo-controllable properties to tungsten trioxide (WO3) is of interest for developing practical applications of WO3 as well as for interpreting such phenomena from scientific viewpoints. Here, a sputtered crystalline WO3 thin film generated thermoelectric power due to ultraviolet (UV) light-induced band-gap excitation and was accompanied by a photochromic reaction resulting from generating W5+ ions. The thermoelectric properties (electrical conductivity (?) and Seebeck coefficient (S)) and coloration of WO3 could be reversibly switched by alternating the external stimulus between UV light irradiation and dark storage. After irradiating the film with UV light, ? increased, whereas the absolute value of S decreased, and the photochromic (coloration) reaction was detected. Notably, the opposite behavior was exhibited by WO3 after dark storage, and this reversible cycle could be repeated at least three times. Moreover, photo-thermoelectric effects (photo-conductive effect (photo-conductivity, ?photo) and photo-Seebeck effect (photo-Seebeck coefficient, Sphoto)) were also detected in response to visible-light irradiation of the colored WO3 thin films. Under visible-light irradiation, ?photo and the absolute value of Sphoto increased and decreased, respectively. These effects are likely attributable to the excitation of electrons from the mid-gap visible light absorption band (W5+ state) to the conduction band of WO3. Our findings demonstrate that the simultaneous, reversible switching of multiple properties of WO3 thin film is achieved by the application of an external stimulus and that this material exhibits photo-thermoelectric effects when irradiated with visible-light.

Azuma, Chiori; Kawano, Takuto; Kakemoto, Hirofumi; Irie, Hiroshi

2014-11-01

297

A Regulatory Perspective on the Decommissioning of Some of the Largest Single Radioactive Sources - Radioisotope Thermoelectric Generators  

Microsoft Academic Search

• to make an analysis of accumulated experience in supervising safety during RTG decommissioning and in mitigating consequences of any incidents and accidents which may occur in the course of the ongoing RTG decommissioning in Russia. It may result in extension of the scope of applicability of the Methodological Guide developed under the previous regulatory project as regards the \\

Malgorzata K. Sneve

298

Crystal Lattice Controlled SiGe Thermoelectric Materials with High Figure of Merit  

NASA Technical Reports Server (NTRS)

Direct energy conversion between thermal and electrical energy, based on thermoelectric (TE) effect, has the potential to recover waste heat and convert it to provide clean electric power. The energy conversion efficiency is related to the thermoelectric figure of merit ZT expressed as ZT=S(exp 2)(sigma)T/Kappa, T is temperature, S is the Seebeck coefficient, sigma is conductance and Kappa is thermal conductivity. For a lower thermal conductivity Kappa and high power factor (S(exp 2)(sigma)), our current strategy is the development of rhombohedrally strained single crystalline SiGe materials that are highly [111]-oriented twinned. The development of a SiGe "twin lattice structure (TLS)" plays a key role in phonon scattering. The TLS increases the electrical conductivity and decreases thermal conductivity due to phonon scattering at stacking faults generated from the 60 X rotated primary twin structure. To develop high performance materials, the substrate temperature, chamber working pressure, and DC sputtering power are controlled for the aligned growth production of SiGe layer and TLS on a c-plane sapphire. Additionally, a new elevated temperature thermoelectric characterization system, that measures the thermal diffusivity and Seebeck effect nondestructively, was developed. The material properties were characterized at various temperatures and optimized process conditions were experimentally determined. The present paper encompasses the technical discussions toward the development of thermoelectric materials and the measurement techniques.

Kim, Hyun-Jung; Park, Yeonjoon; King, Glen C.; Lee, Kunik; Choi, Sang H.

2010-01-01

299

Progress report No. 39 for a program of thermoelectric-generator testing and RTG degradation-mechanisms evaluation  

SciTech Connect

Two neodymium selenide n-type legs and two new p-type Cu-Se legs have been set up for testing. Weight loss measurements for coated Si-Ge material produced by G.E. are reported. The coating on the n-type Si-Ge legs and the n-type side of the Si-Mo hot shoes has disappeared. The coating on the p-type side of the Si-Mo hot shoes has almost completely degraded. It is unlikely that the G.E. coatings have ever been effective. Thermal conductivity measurements are in agreement. The remaining MHW generator on test, Q1-A, has accumulated 28,600 hours and performance remains stable. The performance of the 18 couple modules remains stable. The S/N-1 module has accumulated 30,000 hours and the S/N-3 module has reached 27,300 hours. Telemetry data indicate no changes in the trends of degradation of LES 8 and 9 and the Voyager RTGs.

Lockwood, A.; Shields, V.

1981-01-01

300

High temperature thermoelectric characterization of III-V semiconductor thin films by oxide bonding  

E-print Network

Page 1 High temperature thermoelectric characterization of III-V semiconductor thin films by oxide bonding technique is developed for high temperature thermoelectric characterization of the thin film III-W-N diffusion barrier. A thermoelectric material, thin film ErAs:InGaAlAs metal/semiconductor nanocomposite

Bowers, John

301

Ultrasonic examination techniques for multicouple thermoelectric subcomponents and assemblies: Status report  

SciTech Connect

Since the early 1960s, the United States has been using radioisotope thermoelectric generators (RTGs), developed by the US Department of Energy and its predecessors, for a variety of environments including space. A recent concept in building RTGs uses modular components to allow for an advanced, lighter space mission generator that provides scaled power level outputs. The scalability feature of the modular isotopic thermoelectric generator (MITG) represents a major advance over earlier RTG designs. However, special problems are encountered in applying nondestructive testing methods because of the miniature size of parts that require inspection. This report describes the status of ultrasonic inspection methods being developed to examine the subcomponents and assemblies of the; MITG. The principal emphasis has been to evaluate various bonds between subcomponents using ultrasonic techniques that employ focused search units and a pulse-echo method.

Cook, K.V.; McClung, R.W.; Simpson, W.A. Jr.; Cunningham, R.A. Jr.

1986-09-01

302

Thermoelectric properties of mesoscopic superconductors  

SciTech Connect

We develop a general framework for describing thermoelectric effects in phase-coherent superconducting structures. Formulas for the electrical conductance, thermal conductance, thermopower, and Peltier coefficient are obtained and their various symmetries discussed. Numerical results for both dirty and clean Andreev interferometers are presented. We predict that giant oscillations of the thermal conductance can occur, even when oscillations in the electrical conductance are negligibly small. Results for clean, two-dimensional systems with a single superconducting inclusion are also presented, which show that normal-state oscillations arising from quasiparticle boundary scattering are suppressed by the onset of superconductivity. In contrast, for a clean system with no normal-state boundary scattering, switching on superconductivity induces oscillations in off-diagonal thermoelectric coefficients. {copyright} {ital 1996 The American Physical Society.}

Claughton, N.R.; Lambert, C.J. [School of Physics and Chemistry, Lancaster University, Lancaster, LA14YB (England)] [School of Physics and Chemistry, Lancaster University, Lancaster, LA14YB (England)

1996-03-01

303

Development of steam generator vessel database  

Microsoft Academic Search

The purpose of this project was to collect publicly-available information on Steam Generator (SG) vessel integrity, abstract and summarize the information, and develop a database that could be used for identification of trends. The database developed includes information on 256 SGs (27 of them replacements for originally-installed SGs) in 75 operating Pressurized Water Reactor plants in the United States. The

R. K. Mattu; J. Lauderdale

1992-01-01

304

Fourth-generation photovoltaic concentrator system development  

SciTech Connect

In 1991, under a contract with Sandia for the Concentrator Initiative, the ENTECH team initiated the design and development of a fourth-generation concentrator module. In 1992, Sandia also contracted with ENTECH to develop a new control and drive system for the ENTECH array. This report documents the design and development work performed under both contracts. Manufacturing processes for the new module were developed at the same time under a complementary PVMaT contract with the National Renewable Energy Laboratory. Two 100-kW power plants were deployed in 1995 in Texas using the newly developed fourth-generation concentrator technology, one at the CSW Solar Park near Ft. Davis and one at TUE Energy Park in Dallas. Technology developed under the Sandia contracts has made a successful transition from the laboratory to the production line to the field.

O`Neill, M.J.; McDanal, A.J. [ENTECH, Inc., Dallas-Fort Worth Airport, TX (United States)

1995-10-01

305

Thermoelectric materials evaluation program spring design to minimize load relaxation  

SciTech Connect

The recommended spring material for use in thermoelectric modules is either Inconel x or Elgiloy based on their excellent performance and availability. The stress level for generator applications is 75,000 psi. (FS)

Grimm, F.R.

1980-03-31

306

Effects of MeV Si ions bombardment on the thermoelectric generator from SiO 2/SiO 2 + Cu and SiO 2/SiO 2 + Au nanolayered multilayer films  

NASA Astrophysics Data System (ADS)

The defects and disorder in the thin films caused by MeV ions bombardment and the grain boundaries of these nanoscale clusters increase phonon scattering and increase the chance of an inelastic interaction and phonon annihilation. We prepared the thermoelectric generator devices from 100 alternating layers of SiO 2/SiO 2 + Cu multi-nano layered superlattice films at the total thickness of 382 nm and 50 alternating layers of SiO 2/SiO 2 + Au multi-nano layered superlattice films at the total thickness of 147 nm using the physical vapor deposition (PVD). Rutherford Backscattering Spectrometry (RBS) and RUMP simulation have been used to determine the stoichiometry of the elements of SiO 2, Cu and Au in the multilayer films and the thickness of the grown multi-layer films. The 5 MeV Si ions bombardments have been performed using the AAMU-Center for Irradiation of Materials (CIM) Pelletron ion beam accelerator to make quantum (nano) dots and/or quantum (quantum) clusters in the multilayered superlattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardments we have measured Seebeck coefficient, cross-plane electrical conductivity, and thermal conductivity in the cross-plane geometry for different fluences.

Budak, S.; Chacha, J.; Smith, C.; Pugh, M.; Colon, T.; Heidary, K.; Johnson, R. B.; Ila, D.

2011-12-01

307

In-Line Thermoelectric Module  

SciTech Connect

A thermoelectric module with a plurality of electricity generating units each having a first end and a second end, the units being arranged first end to second end along an-in-line axis. Each unit includes first and second elements each made of a thermoelectric material, an electrically conductive hot member arranged to heat one side of the first element, and an electrically conductive cold member arranged to cool another side of the first element and to cool one side of the second element. The hot member, the first element, the cold member and the second element are supported in a fixture, are electrically connected respectively to provide an electricity generating unit, and are arranged respectively in positions along the in-line axis. The individual components of each generating unit and the respective generating units are clamped in their in-line positions by a loading bolt at one end of the fixture and a stop wall at the other end of the fixture. The hot members may have a T-shape and the cold members an hourglass shape to facilitate heat transfer. The direction of heat transfer through the hot members may be perpendicular to the direction of heat transfer through the cold members, and both of these heat transfer directions maybe perpendicular to the direction-of current flow through the module.

Pento, Robert; Marks, James E.; Staffanson, Clifford D.

1998-07-28

308

Investigation of prototype thermoelectric domestic-ventilator  

Microsoft Academic Search

Applications of thermoelectrics had been enlarged from conventional single refrigeration or generation to waste heat recovery with tough energy consumption of the world. With improvement of living standard more and more domestic air-conditioners are used in Chinese families now. Percentage of power consumption of domestic air-conditioner caused by heat load of fresh air supply increased after SARS, which could be

Tao Li; Guangfa Tang; Guangcai Gong; Guangqiang Zhang; Nianping Li; Lin Zhang

2009-01-01

309

Increasing Thermoelectric Generation Water Use  

E-print Network

rights reserved. Water Is a Critical Resource · Fast growing demand for clean, fresh water · Increased/change · Western US especially vulnerable to water shortages · Water availability impacts ­ Electricity supply;7© 2007 Electric Power Research Institute, Inc. All rights reserved. Strategies to increase fresh water

Keller, Arturo A.

310

Bipolar thermoelectric devices  

E-print Network

The work presented here is a theoretical and experimental study of heat production and transport in bipolar electrical devices, with detailed treatment of thermoelectric effects. Both homojunction and heterojunction devices ...

Pipe, Kevin P. (Kevin Patrick), 1976-

2004-01-01

311

Endoderm Generates Endothelial Cells during Liver Development  

PubMed Central

Summary Organogenesis requires expansion of the embryonic vascular plexus that migrates into developing organs through a process called angiogenesis. Mesodermal progenitors are thought to derive endothelial cells (ECs) that contribute to both embryonic vasculogenesis and the subsequent organ angiogenesis. Here, we demonstrate that during development of the liver, which is an endoderm derivative, a subset of ECs is generated from FOXA2+ endoderm-derived fetal hepatoblast progenitor cells expressing KDR (VEGFR2/FLK-1). Using human and mouse embryonic stem cell models, we demonstrate that KDR+FOXA2+ endoderm cells developing in hepatic differentiation cultures generate functional ECs. This introduces the concept that ECs originate not exclusively from mesoderm but also from endoderm, supported in Foxa2 lineage-tracing mouse embryos by the identification of FOXA2+ cell-derived CD31+ ECs that integrate the vascular network of developing fetal livers. PMID:25358784

Goldman, Orit; Han, Songyan; Hamou, Wissam; Jodon de Villeroche, Vanina; Uzan, Georges; Lickert, Heiko; Gouon-Evans, Valerie

2014-01-01

312

Endoderm Generates Endothelial Cells during Liver Development.  

PubMed

Organogenesis requires expansion of the embryonic vascular plexus that migrates into developing organs through a process called angiogenesis. Mesodermal progenitors are thought to derive endothelial cells (ECs) that contribute to both embryonic vasculogenesis and the subsequent organ angiogenesis. Here, we demonstrate that during development of the liver, which is an endoderm derivative, a subset of ECs is generated from FOXA2+ endoderm-derived fetal hepatoblast progenitor cells expressing KDR (VEGFR2/FLK-1). Using human and mouse embryonic stem cell models, we demonstrate that KDR+FOXA2+ endoderm cells developing in hepatic differentiation cultures generate functional ECs. This introduces the concept that ECs originate not exclusively from mesoderm but also from endoderm, supported in Foxa2 lineage-tracing mouse embryos by the identification of FOXA2+ cell-derived CD31+ ECs that integrate the vascular network of developing fetal livers. PMID:25358784

Goldman, Orit; Han, Songyan; Hamou, Wissam; Jodon de Villeroche, Vanina; Uzan, Georges; Lickert, Heiko; Gouon-Evans, Valerie

2014-10-14

313

Development of a nitrogen generation system  

NASA Technical Reports Server (NTRS)

An eight-stage nitrogen generation module was developed. The design integrated a hydrazine catalytic dissociator, three ammonia dissociation stages and four palladium/silver hydrogen separator stages. Alternating ammonia dissociation and hydrogen separation stages are used to remove hydrogen and ammonia formed in the dissociation of hydrazine which results in negligible ammonia and hydrogen concentrations in the product nitrogen stream. An engineering breadboard nitrogen supply subsystem was also developed. It was developed as an integratable subsystem for a central spacecraft air revitalization system. The subsystem consists of the hydrazine storage and feed mechanism, the nitrogen generation module, the peripheral mechanical and electrical components required to control and monitor subsystem performance, and the instrumentation required to interface with other subsystems of an air revitalization system. The breadboard nitrogen supply subsystem was integrated and tested with a one-person capacity experimental air revitalization system. The integration, checkout and testing was successfully accomplished.

Heppner, D. B.; Marshall, R. D.; Powell, J. D., III; Schubert, F. H.

1980-01-01

314

Development of a NASA standard gas generator  

NASA Technical Reports Server (NTRS)

The goals of the NASA Standard Gas Generator (NSGG) Program are to create a NASA standard gas generating cartridge, characterize its performance, and make it readily available to users. A cartridge within the same envelope as the NASA Standard Initiator (NSI) has the greatest potential use. This potential use is described in viewgraph form. Our approach for NSGG development and qualification was planned to be conducted in several phases. Test methods were developed to evaluate output performance for a variety of potential applications. A feasibility study using modified NSI's was accomplished. Preliminary and final development will be conducted with a delta qualification to evaluate the effects of manufacturing lots and environments. Feasibility study results, feasibility study conclusions, and future plans are presented.

Bement, Laurence J.; Karp, Harold; Schimmel, Morry L.

1993-01-01

315

Development of W-Ta generator  

NASA Technical Reports Server (NTRS)

This research program was used to further develop the existing W-Ta generator and to evaluate alternative adsorbents, preferably inorganic materials, as supports for the generator. During the first half year, combinations of non-complexing eluents and a variety of adsorbents, both inorganic and organic, were evaluated. Some of these adsorbents were synthetic, such as chelate resins that could be specific for tungsten. In the second half of the year, the stress was mainly on the use of complexing eluents because of the high affinity of hydrous oxides for tantalum, on the synthesis of chelate resins and on the use novel techniques (electrolytic) to solve the tantalum-adsorption problem.

1981-01-01

316

Thermoelectric Properties of Selenides Spinels  

NASA Technical Reports Server (NTRS)

Many compounds with the spinel structure type have been analyzed for their thermoelectric properties. Published data was used to augment experimental results presented here to select promising thermoelectric spinels.

Snyder, G.; Caillat, T.; Fleurial, J-P.

2000-01-01

317

Highly efficient functional GexPb1-xTe based thermoelectric alloys.  

PubMed

Methods for enhancement of the direct thermal to electrical energy conversion efficiency, upon development of advanced thermoelectric materials, are constantly investigated mainly for efficient implementation of thermoelectric devices in automotive vehicles, for converting the waste heat generated in such engines into useful electrical power and thereby reduction of the fuel consumption and CO2 emission levels. It was recently shown that GeTe based compounds and specifically GeTe-PbTe rich alloys are efficient p-type thermoelectric compositions. In the current research, Bi2Te3 doping and PbTe alloying effects in GexPb1-xTe alloys, subjected to phase separation reactions, were investigated for identifying the phase separation potential for enhancement of the thermoelectric properties beyond a pure alloying effect. All of the investigated compositions exhibit maximal dimensionless figure of merit, ZT, values beyond 1, with the extraordinary value of 2.1 found for the 5% Bi2Te3 doped-Ge0.87Pb0.13Te composition, considered as among the highest ever reported. PMID:25133859

Gelbstein, Yaniv; Davidow, Joseph

2014-10-01

318

New developments in PHOKHARA Monte Carlo generator  

E-print Network

The present status of the physics program, which led to the development of the Monte Carlo event generator PHOKHARA is described. The possibility of using the radiative return method in various aspects of hadronic physics, from the measurement of the hadronic cross section, to detailed investigations of the hadronic dynamics is emphasized. New results are presented showing how to measure baryon form factors using the knowledge of their spin in baryon-antibaryon production with subsequent decay.

Henryk Czyz; Agnieszka Grzelinska; Agnieszka Wapienik

2007-10-23

319

Laboratory development of fourth generation sulphlex binders  

E-print Network

the resistance of the newly developed binder to low temperature fatigue and fracture behavior reflected in the previous generations of Sulphlexes. The cost effectiveness of earlier Sulphlex formulations was hampered by the necessity to use high priced chemical... of fine particles of crystalline sulfur predominantly in the rhombic form. It has a purity of 100 % with a chemical structure of S, . The dicyclopentadiene (DCPD) was composed of an 80 % polyester grade and 20 % reactive codimer. A Diels-Alder reaction...

Menon, Vivek Narayan

2012-06-07

320

Thermoelectric Control Of Temperatures Of Pressure Sensors  

NASA Technical Reports Server (NTRS)

Prototype controlled-temperature enclosure containing thermoelectric devices developed to house electronically scanned array of pressure sensors. Enclosure needed because (1) temperatures of transducers in sensors must be maintained at specified set point to ensure proper operation and calibration and (2) sensors sometimes used to measure pressure in hostile environments (wind tunnels in original application) that are hotter or colder than set point. Thus, depending on temperature of pressure-measurement environment, thermoelectric devices in enclosure used to heat or cool transducers to keep them at set point.

Burkett, Cecil G., Jr.; West, James W.; Hutchinson, Mark A.; Lawrence, Robert M.; Crum, James R.

1995-01-01

321

High-temperature thermoelectric properties of Na(Co0.91, Ni0.09)2O4 fabricated by solution combustion method for power generation.  

PubMed

High-quality nano-sized Na(Co0.91Ni0.09)2O4 powders, i.e., 27 nm in average size, were synthesized by the solution combustion route. The magnitude of the electrical conductivity, the Seebeck coefficient, and the power factor for Na(Co0.91Ni0.09)2O4 depended strongly on the fuel used and followed the order of aspartic acid > glutamic acid > alanine > glycine. The order of the thermoelectric characteristics was consistent with that of the density of Na(Co0.91Ni0.09)2O4. The maximal power factor (1.06 x 10(-3) Wm(-1) K(-2)) was achieved for aspartic acid-processed Na(Co0.91 Ni0.09)2O4 twice-sintered at 800 degrees C. We believe that the solution combustion route was highly effective for fabricating high-efficiency thermoelectric materials. PMID:22849182

Park, K; Choi, J W

2012-04-01

322

Potential impact of ZT = 4 thermoelectric materials on solar thermal energy conversion technologies.  

PubMed

State-of-the-art methodologies for the conversion of solar thermal power to electricity are based on conventional electromagnetic induction techniques. If appropriate ZT = 4 thermoelectric materials were available, it is likely that conversion efficiencies of 30-40% could be achieved. The availability of all solid state electricity generation would be a long awaited development in part because of the elimination of moving parts. This paper presents a preliminary examination of the potential performance of ZT = 4 power generators in comparison with Stirling engines taking into account specific mass, volume and cost as well as system reliability. High-performance thermoelectrics appear to have distinct advantages over magnetic induction technologies. PMID:20196558

Xie, Ming; Gruen, Dieter M

2010-11-18

323

Overview of thermoelectrics for thermal to electrical energy conversion  

NASA Astrophysics Data System (ADS)

The last twenty years have seen a resurgence of interest in thermoelectricity as a means for the utilization of waste heat for both power generation and cooling applications after thirty years of inactivity in this research field. New ideas were introduced and progress with the thermoelectric process was made. Recently a new wave of ideas has appeared together with a second wave of new activity.

Dresselhaus, Mildred

2013-03-01

324

18 CFR 801.12 - Electric power generation.  

Code of Federal Regulations, 2011 CFR

...generation of electric power at hydro, pumped storage, and thermoelectric generating stations. Increased demands for electric...considerable potential for additional pumped storage and thermoelectric generation. The direct and indirect effects of...

2011-04-01

325

18 CFR 801.12 - Electric power generation.  

Code of Federal Regulations, 2012 CFR

...generation of electric power at hydro, pumped storage, and thermoelectric generating stations. Increased demands for electric...considerable potential for additional pumped storage and thermoelectric generation. The direct and indirect effects of...

2012-04-01

326

18 CFR 801.12 - Electric power generation.  

...generation of electric power at hydro, pumped storage, and thermoelectric generating stations. Increased demands for electric...considerable potential for additional pumped storage and thermoelectric generation. The direct and indirect effects of...

2014-04-01

327

18 CFR 801.12 - Electric power generation.  

Code of Federal Regulations, 2013 CFR

...generation of electric power at hydro, pumped storage, and thermoelectric generating stations. Increased demands for electric...considerable potential for additional pumped storage and thermoelectric generation. The direct and indirect effects of...

2013-04-01

328

Thermoelectrically cooled water trap  

DOEpatents

A water trap system based on a thermoelectric cooling device is employed to remove a major fraction of the water from air samples, prior to analysis of these samples for chemical composition, by a variety of analytical techniques where water vapor interferes with the measurement process. These analytical techniques include infrared spectroscopy, mass spectrometry, ion mobility spectrometry and gas chromatography. The thermoelectric system for trapping water present in air samples can substantially improve detection sensitivity in these analytical techniques when it is necessary to measure trace analytes with concentrations in the ppm (parts per million) or ppb (parts per billion) partial pressure range. The thermoelectric trap design is compact and amenable to use in a portable gas monitoring instrumentation.

Micheels, Ronald H. (Concord, MA)

2006-02-21

329

Development of NO Generator for Medical Applications  

NASA Astrophysics Data System (ADS)

Since NO was identified as effective in treatments involving endothelium-derived relaxing factor in 1987, inhalation of NO (iNO) has been widely used in the medical treatment of acute respiratory distress syndrome, acute lung injury, high blood pressure, and other related illnesses. Current iNO systems usually include a gas cylinder of N2 with a high concentration of NO. This system has an inherent risk of generating nitric dioxide (NO2) if leaked NO mixes with air. NO2 is thought to be toxic to the lungs. Therefore, a system that does not include storage of NO is very desirable for administering iNO. In this paper, Prototype of On-site NO generator, which includes a discharge reactor, a NO2-NO catalyst, a charcoal and a particle filter, is developed for animal experiments.

Namihira, Takao; Wang, Douyan; Katsuki, Sunao; Akiyama, Hidenori; Okamoto, Kazufumi

330

SNAP-8 electrical generating system development program  

NASA Technical Reports Server (NTRS)

The SNAP-8 program has developed the technology base for one class of multikilowatt dynamic space power systems. Electrical power is generated by a turbine-alternator in a mercury Rankine-cycle loop to which heat is transferred and removed by means of sodium-potassium eutectic alloy subsystems. Final system overall criteria include a five-year operating life, restartability, man rating, and deliverable power in the 90 kWe range. The basic technology was demonstrated by more than 400,000 hours of major component endurance testing and numerous startup and shutdown cycles. A test system, comprised of developed components, delivered up to 35 kWe for a period exceeding 12,000 hours. The SNAP-8 system baseline is considered to have achieved a level of technology suitable for final application development for long-term multikilowatt space missions.

1971-01-01

331

Substrate effects on the thermoelectric properties of Co-sputtered Bi-Te thin films for micro-thermoelectric devices  

NASA Astrophysics Data System (ADS)

Among the various thermoelectric materials, bismuth-tellurium (Bi-Te)-based materials are known to have excellent thermoelectric performance near room temperature and are widely used in the thermoelectric industry as thin films for thermoelectric coolers and generators. In this study, thermoelectric Bi-Te thin films, deposited on various substrates such as SiO2 wafers, glass, and sapphire, were fabricated by RF magnetron co-sputtering. The microstructural, electrical, and thermoelectric properties of n-type Bi-Te thin films were investigated. Based on the results of this study, we concluded that the surface roughness and the crystalline structure of the substrate influenced the grain size, crystallinity, and thermoelectric and electrical properties of the Bi-Te thin films. The Bi-Te film deposited on SiO2 had a power factor of 2.96 mW/K2·m without post-annealing. Previous studies have reported power factors of ˜3.0 mW/K2·m for n-type films after annealing.

Lee, Hee-Jung; Han, Seungwoo; Lee, Kwang Eun; Park, Hyun Sung; Kim, Min-Su

2012-11-01

332

Cooling performance of integrated thermoelectric microcooler  

Microsoft Academic Search

A theoretical model for calculating the cooling performance of an integrated thermoelectric microcooler (ITM), which takes into account the effects of substrate thermal bypass, convection and radiation heat loads and electrical and thermal contact resistances, is developed based on a recently proposed device configuration. The model is used to obtain the optimum thermoelement length for achieving maximum cooling performance of

Gao Min; D. M. Rowe

1999-01-01

333

Computer optimization of reactor-thermoelectric space power systems  

NASA Technical Reports Server (NTRS)

A computer simulation and optimization code that has been developed for nuclear space power systems is described. The results of using this code to analyze two reactor-thermoelectric systems are presented.

Maag, W. L.; Finnegan, P. M.; Fishbach, L. H.

1973-01-01

334

Proposal for a phase-coherent thermoelectric transistor  

E-print Network

Identifying materials and devices which offer efficient thermoelectric effects at low temperature is a major obstacle for the development of thermal management strategies for low-temperature electronic systems. Superconductors cannot offer a...

Giazotto, F.; Robinson, J. W. A.; Moodera, J. S.; Bergeret, F. S.

2014-01-01

335

Thermoelectric property studies on carbon-60 doped P-type Bismuth(0.5)Antimony(1.5)Tellurium(3)  

NASA Astrophysics Data System (ADS)

Solid state cooling and power generation based on thermoelectric principles are regarded as one of the technologies with the potential of solving the current energy crisis. Thermoelectric devices could be widely used in waste heat recovery, small scale power generation and refrigeration. It has no moving parts and is environmental friendly. The limitation to its application is due to its low efficiency. Most of the current commercialized thermoelectric materials have a figure of merit (ZT) around 1. The performance of these materials depends on the dimensionless figure-of-merit ZT (= S2sigma T/ kappa), where S is the Seebeck coefficient; sigma is the electrical conductivity; kappa is the thermal conductivity; S2sigma is the power factor and T is the absolute temperature. In recent years, many studies have shown a significant enhancement of figure of merit by utilizing a nanostructuring approach to reduce the thermal conductivity by scattering ph onons more effectively than electrons. The research shows how using a low-cost and mass-production ball milling and hot press compaction nanocomposite process, can improve the power factor by 50% using a temperature range of 60 °C to 80 °C in p-type nanostructured Bi.5Sb1.5Te3 bulk alloys. Further research was developed by using the aforementioned novel approach for cost and time effectiveness by doping C60 to nanocomposite Bi.5Sb1.5Te 3 alloy to improve the figure of merit of thermoelectric materials. The improvement is mainly because of fullerene molecules that provide thermal phonon blocking and particular charge transfer in the nanocomposite. The molecules act as electron traps, and thus decrease the density of free electrons in n-type semiconductors and generate holes in p-type materials. These high performance materials have been investigated to get high efficiency from thermoelectric devices for waste heat recovery, power generation, and cooling applications.

Vemishetti, Aravindkumar

336

Refractory semiconductors for high temperature thermoelectric energy conversion  

NASA Astrophysics Data System (ADS)

Thermoelectric energy conversion utilizing nuclear heat sources has been employed for several decades to generate power for deep space probes. In the past, lead telluride and, more recently, silicon-germanium alloys have been the prime choices as thermoelectric materials for this application. Currently, a number of refractory semiconductors are under investigation at the Jet Propulsion Laboratory in order to produce power sources of higher conversion efficiency and, thus, lower mass per unit of power output. Included among these materials are improved Si-Ge alloys, rare earth compounds and boron-rich borides. The criteria used to select thermoelectric materials, in general, and the above materials, in particular, will be discussed. The current state of the art and the accomplishments to date in thermoelectric materials research will be reviewed.

Wood, Charles

337

Low dimensional thermoelectrics  

Microsoft Academic Search

Enhanced ZT has been predicted theoretically for low dimensional electronic systems under appropriate experimental conditions. Enhanced ZT has been observed experimentally within 2D quantum wells of PbTe, and good agreement between theory and experiment has been obtained. The advantages of low dimensional systems for thermoelectric applications are described, and prospects for further enhancement of ZT are discussed

M. S. Dresselhaus; T. Koga; X. Sun; S. B. Cronin; K. Wang; G. Chen

1997-01-01

338

Thermoelectric Phenomena, Materials, Devices, and Applications  

NASA Astrophysics Data System (ADS)

Thermoelectric materials, which can generate electricity from waste heat or be used as solid-state Peltier coolers, could play an important role in a global sustainable energy solution. However, advanced materials with improved conversion efficiency are required for widespread implementation. Improving thermoelectric efficiency requires reconciling competing electronic and thermal transport properties - a material must have both a large carrier effective mass and mobility and low lattice thermal conductivity. Historically, this has been achieved through engineering carrier scattering rates. This talk will focus on new approaches that achieve these conflicting properties through modifications of the electron and phonon band structures. Example materials such as Yb14MnSb11 and Ba8Ga16Ge30 will be discussed and pathways towards further material improvements will be highlighted. Such tailored control of transport properties will be vital to realize the next generation of energy materials.

Toberer, Eric

2013-03-01

339

Enhancement of automotive exhaust heat recovery by thermoelectric devices  

SciTech Connect

In an effort to improve automobile fuel economy, an experimental study is undertaken to explore practical aspects of implementing thermoelectric devices for exhaust gas energy recovery. A highly instrumented apparatus consisting of a hot (exhaust gas) and a cold (coolant liquid) side rectangular ducts enclosing the thermoelectric elements has been built. Measurements of thermoelectric voltage output and flow and surface temperatures were acquired and analyzed to investigate the power generation and heat transfer properties of the apparatus. Effects of inserting aluminum wool packing material inside the hot side duct on augmentation of heat transfer from the gas stream to duct walls were studied. Data were collected for both the unpacked and packed cases to allow for detection of packing influence on flow and surface temperatures. Effects of gas and coolant inlet temperatures as well as gas flow rate on the thermoelectric power output were examined. The results indicate that thermoelectric power production is increased at higher gas inlet temperature or flow rate. However, thermoelectric power generation decreases with a higher coolant temperature as a consequence of the reduced hot-cold side temperature differential. For the hot-side duct, a large temperature gradient exists between the gas and solid surface temperature due to poor heat transfer through the gaseous medium. Adding the packing material inside the exhaust duct enhanced heat transfer and hence raised hot-side duct surface temperatures and thermoelectric power compared to the unpacked duct, particularly where the gas-to-surface temperature differential is highest. Therefore it is recommended that packing of exhaust duct becomes common practice in thermoelectric waste energy harvesting applications.

Ibrahim, Essam [Alabama A& M University, Normal; Szybist, James P [ORNL; Parks, II, James E [ORNL

2010-01-01

340

Large-scale Ocean-based or Geothermal Power Plants by Thermoelectric Effects  

E-print Network

Heat resources of small temperature difference are easily accessible, free and unlimited on earth. Thermoelectric effects provide the technology for converting these heat resources directly into electricity. We present designs of electricity generators based on thermoelectric effects and using heat resources of small temperature difference, e.g., ocean water at different depths and geothermal sources, and conclude that large-scale power plants based on thermoelectric effects are feasible and economically competitive. The key observation is that the power factor of thermoelectric materials, unlike the figure of merit, can be improved by orders of magnitude upon laminating good conductors and good thermoelectric materials. The predicted large-scale power plants based on thermoelectric effects, if validated, will have a global economic and social impact for its scalability, and the renewability, free and unlimited supply of heat resources of small temperature difference on earth.

Liu, Liping

2012-01-01

341

Brush-Type Connectors for Thermoelectric Elements  

NASA Technical Reports Server (NTRS)

Wire brushes used to connect positive and negative legs of semiconductor thermoelectric generators to power leads and heat sources and sinks. Brushes are flexible thermal and electrical conductors that readily accommodate expansion and contraction of legs with changing temperature. Thus, direct conductive coupling between heat source and sink allowed, in contrast to older and less efficient method of having to couple radiatively to accommodate thermal expansion.

Wood, C.

1986-01-01

342

The thermoelectric properties of molecular junctions can now be investigated with scanning tunnelling microscopy. Such experiments provide insights into charge transport in single  

E-print Network

The thermoelectric properties of molecular junctions can now be investigated with scanning . They used a scanning tunnelling microscope (STM) to investigate thermoelectricity -- the voltage generated that thermoelectric measurements by STM provide a solution to this problem MOLECULAR ELECTRONICS Charges feel the heat

Heller, Eric

343

Thermoelectric properties of porous silicon  

NASA Astrophysics Data System (ADS)

We have studied the thermoelectric properties of porous silicon, a nanostructured, yet single-crystalline form of silicon. Using electrochemical etching, liquid-phase doping, and high-temperature passivation, we show that porous Si can be fabricated such that it has thermoelectric properties superior to bulk Si, for both n- and p-type doping. Hall measurements reveal that the charge carrier mobility is reduced compared to the bulk material which presently limits the increase in thermoelectric efficiency.

de Boor, J.; Kim, D. S.; Ao, X.; Becker, M.; Hinsche, N. F.; Mertig, I.; Zahn, P.; Schmidt, V.

2012-06-01

344

Field Ion Source Development for Neutron Generators  

SciTech Connect

An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption ({approx}20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with {approx}10,000 tip arrays have achieved deuterium ion currents of {approx}50 nA. Neutron production by field ionization has yielded {approx}10{sup 2} n/s from {approx}1 mm{sup 2} of array area using the deuterium-deuterium fusion reaction at 90 kV.

B. Bargsten Johnson; P. R. Schwoebel; C. E. Holland; P. J. Resnick; K. L. Hertz; D. L. Chichester

2012-01-01

345

Powering a Cat Warmer Using Thin-Film Thermoelectric Conversion of Microprocessor  

E-print Network

OF THERMOELECTRIC GENERATION First Waste Heat Recovery from Kerosene Lamp SiGe Nanowires 1822 Cardiac 1970s 2000Powering a Cat Warmer Using ¾� ¿ Thin-Film Thermoelectric Conversion of Microprocessor Waste Heat- tracting waste heat from a high-end microprocessor, converting the heat to electricity using thin

Yang, Junfeng

346

Solar micro-energy harvesting based on thermoelectric and latent heat effects. Part I: Theoretical analysis  

Microsoft Academic Search

This article presents a new method of harvesting ambient renewable micro-energy by using both thermoelectric and latent heat effects. We designed a prototype work unit made of phase change material (PCM) and a thermoelectric generator (TEG) and used a numerical method to inspect system performance. Special attention was paid to the implementation of ambient loading (including solar radiation, temperature variation

Amen Agbossou; Qi Zhang; Gael Sebald; Daniel Guyomar

2010-01-01

347

Thermoelectric automotive waste heat energy recovery using maximum power point tracking  

Microsoft Academic Search

This paper proposes and implements a thermoelectric waste heat energy recovery system for internal combustion engine automobiles, including gasoline vehicles and hybrid electric vehicles. The key is to directly convert the heat energy from automotive waste heat to electrical energy using a thermoelectric generator, which is then regulated by a DC–DC ?uk converter to charge a battery using maximum power

Chuang Yu; K. T. Chau

2009-01-01

348

Encapsulated Thermoelectric Modules for Advanced Thermoelectric Systems  

NASA Astrophysics Data System (ADS)

An encapsulated thermoelectric (TE) module consists of a vacuum-tight stainless-steel container in which an SiGe or BiTe TE module is encapsulated. This construction enables maximum performance and durability because: the thermal expansion mismatch between the hot and cold sides of the container can be accommodated by a sliding sheet in the container; the TE module inside is always kept in a vacuum environment, therefore no oxidation can occur; and the pressure difference between the inside and outside of the container reduces thermal contact resistance inside the container. Our encapsulated SiGe module features higher operating temperature—up to 650°C for both hot and cold sides. Other high-temperature modules and conventional BiTe modules, including both-sides and one-side skeleton types, have been encapsulated. Several variants of the encapsulated module are available. Encapsulated thermoelectric modules with integrated coolers contain cooling panels through which water can pass. If the module hot side is heated by a radiating heat source (radiation coupling) or convection of a hot gas or fluid (convection coupling), no pressing force on the module is necessary. It therefore features minimum contact resistance with the cooling duct, because no pressure is applied, maximum TE power, and minimum installation cost. Another, larger, variant is a quadruple flexible container in which four modules (each of maximum size 40 mm × 40 mm) are encapsulated. These encapsulated modules were used in a powder metallurgy furnace and were in use for more than 3000 h. Application to cryogenic temperatures simulating the liquid nitrogen gas vaporizer has been also attempted.

Kambe, Mitsuru; Jinushi, Takahiro; Ishijima, Zenzo

2014-06-01

349

Skutterudites: Thermoelectric Materials for Automotive Applications?  

NASA Astrophysics Data System (ADS)

The power output of a thermoelectric generator (TEG) was investigated under engine partial-load operation based on measured exhaust gas temperatures and mass flow rates. Materials with properties required for highend temperature TE couples (>500°C) were evaluated. Various possible material combinations for p- and n-legs of these couples as well as the conflicting targets of high efficiency and low cost as required for automotive mass production are discussed. New skutterudite materials for both p- and n-legs as identified during a joint research project are presented, which can help to overcome this conflict. Efficiencies >10% were achieved with these new materials, which have potentially twofold lower production costs than telluride-based materials due to the price of their elements. Some potential for improvement in efficiency and costs has been identified by developing highly integrated TEG units, specifically designed for automotive applications. These initial results of the material development and the evaluation of different integration concepts will be applied in a subsequent step for the fabrication of a pilot number of TEG modules/units.

Salzgeber, K.; Prenninger, P.; Grytsiv, A.; Rogl, P.; Bauer, E.

2010-09-01

350

Geographic, technologic, and economic analysis of using reclaimed water for thermoelectric power plant cooling.  

PubMed

Use of reclaimed water-municipal wastewater treatment plant effluent-in nonpotable applications can be a sustainable and efficient water management strategy. One such nonpotable application is at thermoelectric power plants since these facilities require cooling, often using large volumes of freshwater. To evaluate the geographic, technologic, and economic feasibility of using reclaimed water to cool thermoelectric power plants, we developed a spatially resolved model of existing power plants. Our model integrates data on power plant and municipal wastewater treatment plant operations into a combined geographic information systems and optimization approach to evaluate the feasibility of cooling system retrofits. We applied this broadly applicable methodology to 125 power plants in Texas as a test case. Results show that sufficient reclaimed water resources exist within 25 miles of 92 power plants (representing 61% of capacity and 50% of generation in our sample), with most of these facilities meeting both short-term and long-term water conservation cost goals. This retrofit analysis indicates that reclaimed water could be a suitable cooling water source for thermoelectric power plants, thereby mitigating some of the freshwater impacts of electricity generation. PMID:24625241

Stillwell, Ashlynn S; Webber, Michael E

2014-04-15

351

Rare earth thermoelectrics  

SciTech Connect

The author reviews the thermoelectric properties of metallic compounds which contain rare-earth atoms. They are the group of metals with the largest value ever reported of the Seebeck coefficient. An increase by 50% of the Seebeck would make these compounds useful for thermoelectric devices. The largest Seebeck coefficient is found for compounds of cerium (e.g., CePd{sub 3}) and ytterbium (e.g., YbAl{sub 3}). Theoretical predictions are in agreement with the maximum observed Seebeck. The author discusses the theoretical model which has been used to calculate the Seebeck coefficient. He is solving this model for other configurations (4f){sup n} of rare-earth ground states.

Mahan, G.D.

1997-09-01

352

Next-Generation Ion Propulsion Being Developed  

NASA Technical Reports Server (NTRS)

The NASA Glenn Research Center ion-propulsion program addresses the need for high specific-impulse systems and technology across a broad range of mission applications and power levels. One activity is the development of the next-generation ion-propulsion system as a follow-on to the successful Deep Space 1 system. The system is envisioned to incorporate a lightweight ion engine that can operate over 1 to 10 kW, with a 550-kg propellant throughput capacity. The engine concept under development has a 40-cm beam diameter, twice the effective area of the Deep Space 1 engine. It incorporates mechanical features and operating conditions to maximize the design heritage established by the Deep Space 1 engine, while incorporating new technology where warranted to extend the power and throughput capability. Prototype versions of the engine have been fabricated and are under test at NASA, with an engineering model version in manufacturing. Preliminary performance data for the prototype engine have been documented over 1.1- to 7.3-kW input power. At 7.3 kW, the engine efficiency is 0.68, at 3615-sec specific impulse. Critical component temperatures, including those of the discharge cathode assembly and magnets, have been documented and are within established limits, with significant margins relative to the Deep Space 1 engine. The 1- to 10-kW ion thruster approach described here was found to provide the needed power and performance improvement to enable important NASA missions. The Integrated In-Space Transportation Planning (IISTP) studies compared many potential technologies for various NASA, Government, and commercial missions. These studies indicated that a high-power ion propulsion system is the most important technology for development because of its outstanding performance versus perceived development and recurring costs for interplanetary solar electric propulsion missions. One of the best applications of a highpower electric propulsion system was as an integral part of a solar electric propulsion (SEP) stage to send a payload to outer planet targets. The IISTP studies showed that either trip time or launch vehicle class could be significantly reduced when compared with state-of-the-art systems.

Patterson, Michael J.; Soulas, George C.; Foster, John E.; Haag, Thomas W.; Pinero, Luis R.; Rawlin, Vincent K.; Doehne, S. Michelle

2001-01-01

353

Direct measurements of thermoelectric properties of thin films and nanostructures  

NASA Astrophysics Data System (ADS)

Dwindling energy reserves have created an urgent need for alternative energy sources. Measurement and development of new thermoelectric materials offer an opportunity to recycle the waste heat from energy consumption, transforming it into a viable energy source. Efforts to maximize the dimensionless figure-of-merit ZT rely on accurate and effective measurement techniques. The aim of this poster is to present the design of thermal isolation structures and the thermopower measurements made using these structures on thermoelectric thin films. The unique design of the micromachined structures allows us to make simultaneous measurements of thermopower ? and thermal conductivity k to calculate ZT. We will present the measurement platform design and results from our first measurements on devices with established thermoelectric properties. Finally we will discuss the growth of our first doped amorphous silicon thin films and their potential as an efficient new class of thermoelectric materials.

Sultan, Rubina; Avery, Azure; Zink, Barry

2008-10-01

354

Thermoelectric power enhancement by way of flow impedance for fixed thermal input conditions  

NASA Astrophysics Data System (ADS)

Liquid-to-liquid thermoelectric generators are now being considered for the purpose of converting low cost heat to electricity for local energy uses. The importance in investigating their system efficiency lies in the fact that the generator's purpose is to maintain a heat source and a heat sink for its embedded thermoelectric modules. Of particular importance is the generator's ability to maintain an asymmetric thermal field across its embedded modules since this mechanism partially dictates the devices' thermal to electric conversion efficiency. Indeed, since the modules' semiconductor materials' ability to generate an electromotive force is dependent on the quality of the thermal dipole across the material, gains in thermoelectric generator energy conversion efficiency are made possible with thermal system management. In an effort to improve the system conversion efficiency of a liquid-to-liquid thermoelectric generator (TEG), the present work builds upon recent advancements in TEG inner pipe flow optimisation by investigating the thermoelectric power enhancement brought upon by flow impeding panel inserts in a thermoelectric generator's flow channels for fixed thermal input conditions and with respect to varying insert panel densities. The pumping penalty associated with the flow impedance is measured in order to present and to discuss the net thermoelectric power enhancement.

Amaral, Calil; Brandão, Caio; Sempels, Éric V.; Lesage, Frédéric J.

2014-12-01

355

Development of Organic Ice Nuclei Generators for Weather Modification.  

National Technical Information Service (NTIS)

The development of prototypes of ground and airborne organic smoke generators is addressed. The center of the program reported here involves the development of three kinds of organic ice nuclei generators. Two supporting studies, one on the performance of...

N. Fukuta, M. N. Plooster, J. A. Armstrong, A. Gorove, J. R. Butz

1977-01-01

356

Focus on thermoelectric effects in nanostructures  

NASA Astrophysics Data System (ADS)

The field of nanoscale thermoelectrics began with a clear motivation for better performances of waste heat recovery processes by lowering the system dimensionality. Although this original inspiration still drives many recent developments, the field has also evolved to address fundamental questions on charge and energy transport across quantum conductors in the presence of both voltage and temperature differences. This ‘focus on’ collection provides new perspectives in the field and reports on the latest developments, both theoretically and experimentally.

Sánchez, David; Linke, Heiner

2014-11-01

357

Thermoelectric waste heat recovery from an M1 Abrams tank  

NASA Astrophysics Data System (ADS)

The addition of advanced sensors, targeting systems and electronic countermeasures to military vehicles has created a strategic need for additional electric power. By incorporating a thermoelectric (TE) waste heat recovery system to convert available exhaust heat to electricity, increased electric power needs can be met without reducing the energy efficiency of the vehicle. This approach allows existing vehicles to be upgraded without requiring a complete re-design of the engine and powertrain to support the integration of advanced electronic sensors and systems that keep the performance at the state of the art level. RTI has partnered with General Dynamics Land Systems and Creare, Inc. under an Army Research Lab program to develop a thermoelectric exhaust waste heat recovery system for the M1 Abrams tank. We have designed a reduced-scale system that was retrofitted to the tank and generated 80W of electric power on the vehicle operating on a test track by capturing a portion of the exhaust heat from the Honeywell/Lycoming AGT-1500 gas turbine engine.

Stokes, C. David; Thomas, Peter M.; Baldasaro, Nicholas G.; Mantini, Michael J.; Venkatasubramanian, Rama; Barton, Michael D.; Cardine, Christopher V.; Walker, Grayson W.

2012-06-01

358

Total thermoelectric-power withdrawals Freshwater thermoelectric-power withdrawals Saline-water thermoelectric-power withdrawals  

E-print Network

Total thermoelectric-power withdrawals Freshwater thermoelectric-power withdrawals Saline-water thermoelectric-power withdrawals Louisiana New Hampshire Florida Idaho Washington Oregon Nevada California New,000 9,000 to 13,000 Thermoelectric-power withdrawals by water quality and State, 2005. Estimated Use

359

Weight Penalty Incurred in Thermoelectric Recovery of Automobile Exhaust Heat  

NASA Astrophysics Data System (ADS)

Thermoelectric recovery of automobile waste exhaust heat has been identified as having potential for reducing fuel consumption and environmentally unfriendly emissions. Around 35% of combustion energy is discharged as heat through the exhaust system, at temperatures which depend upon the engine's operation and range from 800°C to 900°C at the outlet port to less than 50°C at the tail-pipe. Beneficial reduction in fuel consumption of 5% to 10% is widely quoted in the literature. However, comparison between claims is difficult due to nonuniformity of driving conditions. In this paper the available waste exhaust heat energy produced by a 1.5 L family car when undergoing the new European drive cycle was measured and the potential thermoelectric output estimated. The work required to power the vehicle through the drive cycle was also determined and used to evaluate key parameters. This enabled an estimate to be made of the engine efficiency and additional work required by the engine to meet the load of a thermoelectric generating system. It is concluded that incorporating a thermoelectric generator would attract a penalty of around 12 W/kg. Employing thermoelectric modules fabricated from low-density material such as magnesium silicide would considerably reduce the generator weight penalty.

Rowe, D. M.; Smith, J.; Thomas, G.; Min, G.

2011-05-01

360

Revisiting Feynman's ratchet with thermoelectric transport theory.  

PubMed

We show how the formalism used for thermoelectric transport may be adapted to Smoluchowski's seminal thought experiment, also known as Feynman's ratchet and pawl system. Our analysis rests on the notion of useful flux, which for a thermoelectric system is the electrical current and for Feynman's ratchet is the effective jump frequency. Our approach yields original insight into the derivation and analysis of the system's properties. In particular we define an entropy per tooth in analogy with the entropy per carrier or Seebeck coefficient, and we derive the analog to Kelvin's second relation for Feynman's ratchet. Owing to the formal similarity between the heat fluxes balance equations for a thermoelectric generator (TEG) and those for Feynman's ratchet, we introduce a distribution parameter ? that quantifies the amount of heat that flows through the cold and hot sides of both heat engines. While it is well established that ? = 1/2 for a TEG, it is equal to 1 for Feynman's ratchet. This implies that no heat may be rejected in the cold reservoir for the latter case. Further, the analysis of the efficiency at maximum power shows that the so-called Feynman efficiency corresponds to that of an exoreversible engine, with ? = 1. Then, turning to the nonlinear regime, we generalize the approach based on the convection picture and introduce two different types of resistance to distinguish the dynamical behavior of the considered system from its ability to dissipate energy. We finally put forth the strong similarity between the original Feynman ratchet and a mesoscopic thermoelectric generator with a single conducting channel. PMID:25122257

Apertet, Y; Ouerdane, H; Goupil, C; Lecoeur, Ph

2014-07-01

361

Thermoelectric Properties of Bismuth and Silicon Nanowires  

NASA Astrophysics Data System (ADS)

Thermoelectric materials convert temperature differences into electricity and vice versa. Such materials utilize the Seebeck effect for power generation and the Peltier effect for refrigeration. In the Seebeck effect, a temperature gradient across a material causes the diffusion of charged carriers across that gradient, thus creating a voltage difference between the hot and cold ends of the material. Conversely, the Peltier effect explains the fact that when current flows through a material a temperature gradient arises because the charged carriers exchange thermal energy at the contacts. Thermoelectrics perform these functions without moving parts and they do not pollute. This makes them highly reliable and more importantly attractive as renewable energy sources, especially at a time when global warming is a growing concern. However, thermoelectrics find only limited use because of their poor efficiency. The efficiency of a thermoelectric material is determined by the dimensionless figure of merit, ZT = S2k T, where S is the thermoelectric power, defined as the thermoelectric voltage, V, produced per degree temperature difference S = dVdT , sigma is the electrical conductivity, kappa is the thermal conductivity, and T is the temperature. To maximize ZT, S must be large so that a small temperature difference can create a large voltage, sigma must be large in order to minimize joule heating losses, and kappa must be small to reduce heat leakage and maintain a temperature difference. Maximizing ZT is challenging because optimizing one physical parameter often adversely affects another. The best commercially available thermoelectric devices are alloys of Bi2Te3 and have a ZT of 1 which corresponds to a cannot efficiency of ˜10%. My research has focused on achieving efficient thermoelectric performance from the single component systems of bismuth and silicon nanowires. Bismuth nanowires are predicted to undergo a semi-metal to semiconductor transition below a size of 50 nm which should increase the thermopower and thus ZT. Limited experimental evidence by other groups has been acquired to support this claim. Through electric field gating measurements and by tuning the nanowire size, we have shown that no such transition occurs. Instead, surface states dominate the electric transport at a size smaller than 50 nm and bismuth remains a semimetal. Bulk silicon is a poor thermoelectric due to its large thermal conductivity. However, silicon nanowires may have a dramatically reduced thermal conductivity. By varying the nanowire size and impurity doping levels, ZT values representing an approximately 100-fold improvement over bulk silicon are achieved over a broad temperature range, including a ZT ˜ 1 at 200K. Independent measurements of S, sigma, and kappa, combined with theory, indicate that the improved efficiency originates from phonon effects. The thermal conductivity is reduced and the thermopower is enhanced. These results are expected to apply to other classes of semiconductor nanomaterials.

Boukai, Akram Issam

362

Riverine ecosystem services and the thermoelectric sector: strategic issues facing the Northeastern United States  

NASA Astrophysics Data System (ADS)

Major strategic issues facing the global thermoelectric sector include environmental regulation, climate change and increasing electricity demand. We have addressed such issues by modeling thermoelectric generation in the Northeastern United States that is reliant on cooling under five sensitivity tests to evaluate losses/gains in power production, thermal pollution and suitable aquatic habitat, comparing the contemporary baseline (2000-2010) with potential future states. Integral to the analysis, we developed a methodology to quantify river water availability for cooling, which we define as an ecosystem service. Projected climate conditions reduce river water available for efficient power plant operations and the river's capacity to absorb waste heat, causing a loss of regional thermoelectric generation (RTG) (2.5%) in some summers that, compared to the contemporary baseline, is equal to the summertime electricity consumption of 1.3 million Northeastern US homes. Vulnerabilities to warm temperatures and thermal pollution can be alleviated through the use of more efficient natural gas (NG) power plants that have a reduced reliance on cooling water. Conversion of once-through (OT) to cooling tower (CT) systems and the Clean Water Act (CWA) temperature limit regulation, both of which reduce efficiencies at the single plant level, show potential to yield beneficial increases in RTG. This is achieved by obviating the need for large volumes of river water, thereby reducing plant-to-plant interferences through lowering the impact of upstream thermal pollution and preserving a minimum standard of cooling water. The results and methodology framework presented here, which can be extrapolated to other regional assessments with contrasting climates and thermoelectric profiles, can identify opportunities and support decision-making to achieve more efficient energy systems and riverine ecosystem protection.

Miara, A.; Vorosmarty, C. J.; Stewart, R.; Wollheim, W. M.; Rosenzweig, B.

2013-12-01

363

High performance thermoelectric nanocomposite device  

SciTech Connect

A thermoelectric device includes a nanocomposite material with nanowires of at least one thermoelectric material having a predetermined figure of merit, the nanowires being formed in a porous substrate having a low thermal conductivity and having an average pore diameter ranging from about 4 nm to about 300 nm.

Yang, Jihui (Lakeshore, CA); Snyder, Dexter D. (Birmingham, MI)

2011-10-25

364

Quantum interference in thermoelectric molecular junctions: A toy model perspective  

NASA Astrophysics Data System (ADS)

Quantum interference (QI) phenomena between electronic states in molecular circuits offer a new opportunity to design new types of molecular devices such as molecular sensors, interferometers, and thermoelectric devices. Controlling the QI effect is a key challenge for such applications. For the development of single molecular devices employing QI effects, a systematic study of the relationship between electronic structure and the quantum interference is needed. In order to uncover the essential topological requirements for the appearance of QI effects and the relationship between the QI-affected line shape of the transmission spectra and the electronic structures, we consider a homogeneous toy model where all on-site energies are identical and model four types of molecular junctions due to their topological connectivities. We systematically analyze their transmission spectra, density of states, and thermoelectric properties. Even without the degree of freedom for on-site energies an asymmetric Fano peak could be realized in the homogeneous systems with the cyclic configuration. We also calculate the thermoelectric properties of the model systems with and without fluctuation of on-site energies. Even under the fluctuation of the on-site energies, the finite thermoelectrics are preserved for the Fano resonance, thus cyclic configuration is promising for thermoelectric applications. This result also suggests the possibility to detect the cyclic configuration in the homogeneous systems and the presence of the QI features from thermoelectric measurements.

Nozaki, Daijiro; Avdoshenko, Stas M.; Sevinçli, Hâldun; Cuniberti, Gianaurelio

2014-08-01

365

Understanding of the contact of nanostructured thermoelectric n-type Bi[subscript 2]Te[subscript 2.7]Se[subscript 0.3] legs for power generation applications  

E-print Network

Traditional processes of making contacts (metallization layer) onto bulk crystalline Bi2Te3-based materials do not work for nanostructured thermoelectric materials either because of weak bonding strength or an unstable ...

Liu, Weishu

366

Development of microthermoelectric generators using integrated suspending bridge-type polysilicon thin-film thermopiles  

NASA Astrophysics Data System (ADS)

We describe the development of novel suspension bridge-type microthermoelectric generators (?-TEGs) having 64,000 to 147,000 serial-connected thermocouples in a 1-centimeter-square chip area using surface micromachining techniques. Each microthermocouple is constructed by a pair of n/p bridge-type polysilicon thin-film thermolegs and a pair of cold- and hot-side Cr/Au metal planes. Under a controlled fixed temperature difference between the cold/hot sides, the open-circuit voltage and the output power of the proposed ?-TEGs are simulated by commercial software (ANSYS). The influences of thermocouple thermo-leg dimensions and number of thermocouples on the thermoelectric characteristics of presented ?-TEGs are investigated. The implemented suspension bridge-type thermopile has a 2.5-?m-height air-gap separation from substrate and its fabrication yield is higher than 75% in the laboratory environment. The measured maximum temperature difference between the cold/hot sides of the proposed ?-TEGs is about 1.29°C, a maximum open-circuit voltage of 4.64 V/cm2 and output power of 0.65 ?W/cm2 can be obtained.

Huang, I.-Yu; Chen, Guan-Ming; Wu, Ting-Yi

2013-01-01

367

Cascaded Thermoelectric Conversion-Advanced Radioisotope Power Systems (CTC-ARPSs)  

NASA Astrophysics Data System (ADS)

Conceptual designs of Advanced Radioisotope Power System (ARPS) with Cascaded Thermoelectric Converters (CTCs) are developed and optimized for maximum efficiency operation for End-Of Mission (EOM) electrical power of at least 100 We. These power systems each employs four General Purpose Heat Source (GPHS) bricks generating 1000 Wth at Beginning-of-Life (BOL) and 32 Cascaded Thermoelectric Modules (CTMs). Each CTM consists of a top and a bottom array of thermoelectric unicouples, which are thermally, but not electrically, coupled. The top and bottom arrays of the CTMs are connected electrically in series in two parallel strings with the same nominal voltage of > 28 VDC. The SiGe unicouples in the top array of the CTMs are optimized for nominal hot shoe temperature of 1273 K and constant cold shoe temperature of either 780 K or 980 K, depending on the thermoelectric materials of the unicouples in the bottom array. For a SiGe cold junction temperature of 780 K, the unicouples in the bottom array have p-legs of TAGS-85 and n-legs of 2N-PbTe and operate at constant hot junction temperature of 765 K and nominal cold junction temperature of 476.4 K. When the SiGe cold junction temperature is 980 K, the unicouples in the bottom arrays of CTMs have p-legs of CeFe3.5Co0.5Sb12 or CeFe3.5Co0.5Sb12 and Zn4Sb3, segments and n-legs of CoSb3 and operate at constant hot junction temperature of 965 K and nominal cold junction temperatures of 446.5 K or 493.5 K, respectively. The CTC-ARPSs have a nominal efficiency of 10.82% - 10.85% and generate BOL power of 108 We. This system efficiency is ~ 80% higher than that of State-of-the-Art (SOA) Radioisotope Thermoelectric Generators (RTGs), requiring 7 GHPS bricks and generating 105 We at BOL. The CTC-ARPSs have specific powers of 8.2 We/kg to 8.8 We/kg, which are 71% to 83% higher, respectively, than that of the SOA-RTGs, and use ~ 43% less 238PuO2 fuel.

El-Genk, Mohamed S.; Saber, Hamed H.

2004-02-01

368

Dimensional Analysis of Thermoelectric Modules Under Constant Heat Flux  

NASA Astrophysics Data System (ADS)

Thermoelectric power generation is examined in the case of radiative heating. A constant heat flux is assumed in addition to consideration of the Seebeck effect, Peltier effect, and Joule heating with temperature-dependent material properties. Numerical evaluations are conducted using a combination of the finite-volume method and an original simultaneous solver for the heat transfer, thermoelectric, and electric transportation phenomena. Comparison with experimental results shows that the new solver could work well in the numerical calculations. The calculations predict that the Seebeck effect becomes larger for longer thermoelectric elements because of the larger temperature difference. The heat transfer to the cold surface is critical to determine the junction temperatures under a constant heat flux from the hot surface. The negative contribution from Peltier cooling and heating can be minimized when the current is smaller for longer elements. Therefore, a thicker TE module can generate more electric power even under a constant heat flux.

Suzuki, Ryosuke O.; Fujisaka, Takeyuki; Ito, Keita O.; Meng, Xiangning; Sui, Hong-Tao

2014-08-01

369

A high-efficiency thermoelectric converter for space applications  

SciTech Connect

This paper presents a concept for using high-temperature superconducting materials in thermoelectric generators (SCTE) to produce electricity at conversion efficiencies approaching 50% of the Carrot efficiency. The SCTE generator is applicable to systems operating in temperature ranges of high-temperature superconducting materials and thus would be a low-grade converter. Operating in cryogenic temperature ranges provides the advantage of inherently increasing the limits of the Carrot efficiency. Potential applications are for systems operating in space where the ambient temperatures are in the cryogenic temperature range. The advantage of using high-temperature superconducting material in a thermoelectric converter is that it would significantly reduce or eliminate the Joule heating losses in a thermoelectric element. This paper investigates the system aspects and the material requirements of the SCTE converter concept, and presents a conceptual design and an application for a space power system.

Metzger, J.D. [Westinghouse Savannah River Co., Aiken, SC (United States); El-Genk, M.S. [New Mexico Univ., Albuquerque, NM (United States). Inst. for Space Nuclear Power Studies

1990-12-31

370

A high-efficiency thermoelectric converter for space applications  

SciTech Connect

This paper presents a concept for using high-temperature superconducting materials in thermoelectric generators (SCTE) to produce electricity at conversion efficiencies approaching 50% of the Carrot efficiency. The SCTE generator is applicable to systems operating in temperature ranges of high-temperature superconducting materials and thus would be a low-grade converter. Operating in cryogenic temperature ranges provides the advantage of inherently increasing the limits of the Carrot efficiency. Potential applications are for systems operating in space where the ambient temperatures are in the cryogenic temperature range. The advantage of using high-temperature superconducting material in a thermoelectric converter is that it would significantly reduce or eliminate the Joule heating losses in a thermoelectric element. This paper investigates the system aspects and the material requirements of the SCTE converter concept, and presents a conceptual design and an application for a space power system.

Metzger, J.D. (Westinghouse Savannah River Co., Aiken, SC (United States)); El-Genk, M.S. (New Mexico Univ., Albuquerque, NM (United States). Inst. for Space Nuclear Power Studies)

1990-01-01

371

Decoupling interrelated parameters for designing high performance thermoelectric materials.  

PubMed

The world's supply of fossil fuels is quickly being exhausted, and the impact of their overuse is contributing to both climate change and global political unrest. In order to help solve these escalating problems, scientists must find a way to either replace combustion engines or reduce their use. Thermoelectric materials have attracted widespread research interest because of their potential applications as clean and renewable energy sources. They are reliable, lightweight, robust, and environmentally friendly and can reversibly convert between heat and electricity. However, after decades of development, the energy conversion efficiency of thermoelectric devices has been hovering around 10%. This is far below the theoretical predictions, mainly due to the interdependence and coupling between electrical and thermal parameters, which are strongly interrelated through the electronic structure of the materials. Therefore, any strategy that balances or decouples these parameters, in addition to optimizing the materials' intrinsic electronic structure, should be critical to the development of thermoelectric technology. In this Account, we discuss our recently developed strategies to decouple thermoelectric parameters for the synergistic optimization of electrical and thermal transport. We first highlight the phase transition, which is accompanied by an abrupt change of electrical transport, such as with a metal-insulator and semiconductor-superionic conductor transition. This should be a universal and effective strategy to optimize the thermoelectric performance, which takes advantage of modulated electronic structure and critical scattering across phase transitions to decouple the power factor and thermal conductivity. We propose that solid-solution homojunction nanoplates with disordered lattices are promising thermoelectric materials to meet the "phonon glass electron crystal" approach. The formation of a solid solution, coupled with homojunctions, allows for synergistically enhanced thermoelectric properties. This occurs through a significant reduction of thermal conductivity, without the deterioration of thermopower and electrical conductivity. In addition, we introduce the concept of spin entropy in wide band gap semiconductor nanocrystals, which acts to fully disentangle the otherwise interconnected quantities for synergistically optimized thermoelectric performance. Finally, we discuss a new concept we developed that is based on an ultrathin-nanosheet composite that we fabricated from ultrathin nanosheets of atomic thickness. These retain the original strong two-dimensional electron gas (2DEG) and allow for decoupled optimization of the three thermoelectric parameters, which improves thermoelectric performance. PMID:24517646

Xiao, Chong; Li, Zhou; Li, Kun; Huang, Pengcheng; Xie, Yi

2014-04-15

372

Thermoelectric AC power sensor by CMOS technology  

Microsoft Academic Search

The authors report the development of a thermoelectric AC power sensor (thermoconverter) realized by industrial CMOS IC technology in combination with postprocessing micromachining. The sensor is based on a polysilicon heating resistor and a polysilicon\\/aluminum thermopile integrated on an oxide microbridge. The thermopile sensitivity is 9.9 mV\\/mW and the burn-out power of the sensor is 50 mW. The time constant

Dominik Jaeggi; Henry Baltes; David Moser

1992-01-01

373

Modeling Energy Recovery Using Thermoelectric Conversion Integrated with an Organic Rankine Bottoming Cycle  

SciTech Connect

Hot engine exhaust represents a resource that is often rejected to the environment without further utilization. This resource is most prevalent in the transportation sector, but stationary engine-generator systems also typically do not utilize this resource. Engine exhaust is a source of high grade thermal energy that can potentially be utilized by various approaches to produce electricity or to drive heating and cooling systems. This paper describes a model system that employs thermoelectric conversion as a topping cycle integrated with an organic Rankine bottoming cycle for waste heat utilization. This approach is being developed to fully utilize the thermal energy contained in hot exhaust streams. The model is composed of a high temperature heat exchanger which extracts thermal energy for driving the thermoelectric conversion elements. However, substantial sensible heat remains in the exhaust stream after emerging from the heat exchanger. The model incorporates a closely integrated bottoming cycle to utilize this remaining thermal energy in the exhaust stream. The model has many interacting parameters that define combined system quantities such as overall output power, efficiency, and total energy utilization factors. In addition, the model identifies a maximum power operating point for the system. That is, the model can identify the optimal amount of heat to remove from the exhaust flow to run through the thermoelectric elements. Removing too much or too little heat from the exhaust stream in this stage will reduce overall cycle performance. The model has been developed such that heat exchanger UAh values, thermal resistances, ZT values, and multiple thermoelectric elements can be investigated in the context of system operation. The model also has the ability to simultaneously determine the effect of each cycle design parameter on the performance of the overall system, thus giving the ability to utilize as much waste heat as possible. Key analysis results are presented showing the impact of critical design parameters on power output, system performance and inter-relationships between design parameters in governing performance.

Miller, Erik W.; Hendricks, Terry J.; Peterson, Richard B.

2009-07-01

374

Development of an automatic block generation algorithm  

NASA Technical Reports Server (NTRS)

A method for automatic multiblock grid generation is described. The method combines the modified advancing front method as a predictor with an elliptic scheme as a corrector. It advances a collection of cells by one cell height in the outward direction using modified advancing front method, and then corrects newly-obtained cell positions by solving elliptic equations. This predictor-corrector type scheme is repeatedly applied until the field of interest is filled with hexahedral grid cells. Given the configuration surface grid, the scheme produces block layouts as well as grid cells with overall smoothness as its output. The method saves human-time and reduces the burden on the user in generating grids for general 3D configurations. It is used to generate multiblock grids for wings in their high-lift configuration.

Eberhardt, Scott; Kim, Byoungsoo

1995-01-01

375

Superlattices in thermoelectric applications  

SciTech Connect

The electrical conductivity, thermopower and the electronic contribution to the thermal conductivity of a superlattice, are calculated with the electric field and the thermal gradient applied parallel to the interfaces. Tunneling between quantum wells is included. The broadening of the lowest subband when the period of the superlattice is decreased produces a reduction of the thermoelectric figure of merit. However, we found that a moderate increase of the figure of merit may be expected for intermediate values of the period, due to the enhancement of the density of states produced by the superlattice structure. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Sofo, J.O.; Mahan, G.D. [Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6030 (United States)]|[Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996-1200 (United States)

1994-08-10

376

Superlattices in thermoelectric applications  

SciTech Connect

The electrical conductivity, thermopower and the electronic contribution to the thermal conductivity of a superlattice, are calculated with the electric field and the thermal gradient applied parallel to the interfaces. Tunneling between quantum wells is included. The broadening of the lowest subband when the period of the superlattice is decreased produces a reduction of the thermoelectric figure of merit. However, we found that a moderate increase of the figure of merit may be expected for intermediate values of the period, due to the enhancement of the density of states produced by the superlattice structure.

Sofo, J.O.; Mahan, G.D. [Oak Ridge National Lab., TN (United States)]|[Tennessee Univ., Knoxville, TN (United States). Dept. of Physics and Astronomy

1994-08-01

377

Withdrawal and consumption of water by thermoelectric power plants in the United States, 2010  

USGS Publications Warehouse

Estimates of water use at thermoelectric plants were developed by the U.S. Geological Survey based on linked heat and water budgets, and complement reported thermoelectric water withdrawals and consumption. The heat- and water-budget models produced withdrawal and consumption estimates, including thermodynamically plausible ranges of minimum and maximum withdrawal and consumption, for 1,290 water-using plants in the United States for 2010. Total estimated withdrawal for 2010 was about 129 billion gallons per day (Bgal/d), and total estimated consumption was about 3.5 Bgal/d. In contrast, total withdrawal reported by the U.S. Department of Energy, Energy Information Administration (EIA), was about 24 percent higher than the modeled estimates, and total EIA-reported consumption was about 8 percent lower. Most thermoelectric generation in 2010 was not associated with thermodynamically plausible EIA-reported values of both withdrawal and consumption. An analysis of 2005 and 2010 EIA-reported water use indicated that withdrawal and consumption declined 18 percent and 34 percent, respectively. Alternative water types (types other than freshwater) accounted for approximately 25 percent of all withdrawals in 2010, most of which occurred at plants with once-through cooling systems using saline and brackish tidal waters. Differences among withdrawal and consumption coefficients based on EIA-reported water use for 2005 and 2010 and heat-budget model results for 2010 reveal opportunities for improving consistency and accuracy of reporting of water-use information at the plant scale.

Diehl, Timothy H.; Harris, Melissa A.

2014-01-01

378

Generation and transmission improvements in developing countries  

Microsoft Academic Search

This paper discusses new realities in power development in developing countries as seen by the United Nations, The World Energy Council, Asia, Latin America, and Africa. At the outset, technical assistance given by the United Nations for global sustainability projects is summarised. Power system expansion and interconnection in China, greenhouse gas emission reduction in Egypt, and integrated development of the

T. J. Hammons; M. Willingham; K. N. Mak; M. Da Silva; M. Morozowski; B. K. Blyden

1999-01-01

379

Thermoelectric integrated membrane evaporation water recovery technology  

NASA Technical Reports Server (NTRS)

The recently developed Thermoelectric Integrated Membrane Evaporation Subsystem (TIMES) offers a highly competitive approach to water recovery from waste fluids for future on-orbit stations such as the Space Operations Center. Low power, compactness and gravity insensitive operation are featured in this vacuum distillation subsystem that combines a hollow fiber membrane evaporator with a thermoelectric heat pump. The hollow fiber elements provide positive liquid/gas phase control with no moving parts other than pumps and an accumulator, thus solving problems inherent in other reclamation subsystem designs. In an extensive test program, over 850 hours of operation were accumulated during which time high quality product water was recovered from both urine and wash water at an average steady state production rate of 2.2 pounds per hour.

Roebelen, G. J., Jr.; Winkler, H. E.; Dehner, G. F.

1982-01-01

380

Temperature-dependent elastic moduli of lead telluride-based thermoelectric materials  

SciTech Connect

This study provides the first measurements of the temperature dependence of Young's modulus and Poisson's ratio for Ag-, Sb-, Sn-, and S- doped PbTe thermoelectric materials between room temperature and 723 K. Specimens cut from both cast ingots and hot pressed billets were included in the study. A critical potential application of these materials is as thermoelectric generators, producing electrical energy from waste heat. Knowledge of the elastic moduli as a function of temperature is essential for the design of thermoelectric generators since both analytical and Finite Element stress calculations require knowledge of the temperature-dependence of these properties.

Ren, Fei [Michigan State University, East Lansing; Case, Eldon D [Michigan State University, East Lansing; Ni, Jennifer E. [Michigan State University, East Lansing; Timm, Edward J [Michigan State University, East Lansing; Lara-Curzio, Edgar [ORNL; Trejo, Rosa M [ORNL; Lin, Chia-Her [Michigan State University, East Lansing; Kanatzidis, Mercouri G. [Northwestern University, Evanston

2009-01-01

381

Study of solar-assisted thermoelectric technology for automobile air conditioning  

Microsoft Academic Search

An analytical study was conducted to determine the feasibility of employing solar energy assisted thermoelectric (TE) cooling technology in automobile air conditioners. The study addressed two key issues -- power requirements and availability of thermoelectric materials. In this paper a mathematical model was developed to predict the performance of TE air conditioners and to analyze power consumption. Results show that

V. C. Mei; F. C. Chen; B. Mathiprakasam; P. Heenan

1993-01-01

382

Thermoelectric Microdevice Fabrication Process and Evaluation at the Jet Propulsion Laboratory (JPL)  

E-print Network

Thermoelectric Microdevice Fabrication Process and Evaluation at the Jet Propulsion Laboratory (JPL Laboratory/California Institute of Technology 4800 Oak Grove Drive, Pasadena, CA 91109 USA James.R.Lim@jpl Group at JPL, we have developed a unique fabrication method for a thermoelectric microdevice

383

Thermoelectric device characterization and solar thermoelectric system modeling  

E-print Network

Recent years have witnessed a trend of rising electricity costs and an emphasis on energy efficiency. Thermoelectric (TE) devices can be used either as heat pumps for localized environmental control or heat engines to ...

Muto, Andrew (Andrew Jerome)

2011-01-01

384

Next Generation LOCAD-PTS Cartridge Development  

NASA Technical Reports Server (NTRS)

Future astrobiology exploration missions will require rapid, point-of-use techniques for surface science experiments and contamination monitoring. The Lab-On-a-Chip Application Development (LOCAD) team is developing operational instruments that advance spaceflight technologies to molecular-based methods. Currently, LOCAD-Portable Test System (PTS) is quantifying levels of the bacterial molecule endotoxin onboard the Internatioal Space Station. Future research and development will focus on more sensitive molecular techniques that expand the number of compounds detected to include beta-glucan from fungal cell walls.

Morris, H.; Nutter, D.; Weite, E.; Wells, M.; Maule, J.; Damon, M.; Monaco, L.; Steele, A.; Wainwright, N.

2008-01-01

385

Thermoelectric properties in gallium telluride-gallium antimonide vacancy compounds  

NASA Astrophysics Data System (ADS)

Thermoelectric materials with high figure of merit, which requires large Seebeck coefficient, large electrical conductivity and low thermal conductivity, are of great importance in solid state cooling and power generation. Solid solution formation is one effective method to achieve low thermal conductivity by phonon scattering due to mass and strain field fluctuation. This type of scattering is maximized in structures containing vacancies. The thermoelectric properties of the vacancy compounds of Ga2Te3-GaSb are studied in this research. We find that the lattice thermal conductivity is reduced by over an order of magnitude with the addition of only very moderate amounts of Ga2Te3. Additionally, both the carrier type and concentration can be modified with the addition of Ga2Te 3. While the vacancy structure induced by the addition of Ga2Te 3 to GaSb can effectively reduce phonon conductivity, carrier mobility is also degraded. Thus the optimized thermoelectric properties require careful control of the vacancy content in these solid solutions. The effect of preparation methods on thermoelectric properties of these solid solutions has also been studied. The influence of extrinsic doping and isoelectronic substitution on thermoelectric performance of Ga2Te3-GaSb is also discussed in this work.

Yang, Hao

386

Generation and transmission improvements in developing countries  

SciTech Connect

This paper discusses new realities in Power Development in Developing Countries as seen by the United Nations, The World Energy Council, Asia, Latin America, and Africa. At the outset, technical assistance given by the United Nations for global sustainability projects is summarized. Power system expansion and interconnection in China, greenhouse gas emission reduction in Egypt, and integrated development of the Arab-Mediterranean Regional and environmental considerations are among the projects that are highlighted. The pressing need of Developing Countries as seen by the World Energy Council to meet energy needs without prejudice to the environment where technological advances in the production, delivery and utilization of electrical energy are central to resolving conflicts between energy and the environment is then discussed. The paper goes on to discuss power system planning in deregulated environments where the Brazilian experience is highlighted. Global dynamics and potential for an integrated African Grid is then examined. Concepts associated with the growing interest in renewable resources in Central and East Africa for domestic, continental and international utilization are synthesized. Current and future energy development proposals are discussed with emphasis on operational reliability as a basis for potential large system design. Given are generalized representations to illustrate hydroelectric potential of the Central and East African regions and the kind of centralized pool that could be developed as a result. Other studies which include the Africa-Europe and Zaire-Egypt initiatives are also discussed.

Hammons, T.J.; Willingham, M.; Mak, K.N.; Da Silva, M.; Morozowski, M.; Blyden, B.K.

1999-09-01

387

Synthesis and Characterization of New Ceramic Thermoelectrics Implemented in a Thermoelectric Oxide Module  

NASA Astrophysics Data System (ADS)

Novel thermoelectric oxides were developed, produced, and characterized to demonstrate their promising thermoelectric conversion potential in a thermoelectric converter. Four-leg thermoelectric oxide modules were fabricated by combining p- and n-type oxide thermoelements made of pressed polycrystalline GdCo0.95Ni0.05O3 and CaMn0.98Nb0.02O3, respectively. In these modules, the p- and n-type thermoelements were connected electrically in series and thermally in parallel. The materials were joined by electrical contacts consisting of a Ag/CuO composite material. Fairly good thermal contacts were ensured by pressing the thermoelements between alumina substrates. Cross-sections of the alumina/Ag-CuO mixture/thermoelement interface were investigated by scanning electron microscopy. The temperature distribution across the module was monitored using K-type thermocouples and a micro-infrared (IR) camera. The open-circuit voltage and the load voltages of the module were measured up to a temperature difference of ? T = 500 K while keeping the temperature of the cold side at 300 K. The output power and internal resistance were calculated. The characteristics of the module evaluated from electrical measurements were compared with respective values of the p- and n-type leg materials. An output power of 0.04 W at ? T = 500 K led to a power density of ~0.125 W/cm3, where the volume of thermoelectric material was determined by a cross-section of 4 mm × 4 mm and a leg length of 5 mm.

Tomeš, P.; Robert, R.; Trottmann, M.; Bocher, L.; Aguirre, M. H.; Bitschi, A.; Hejtmánek, J.; Weidenkaff, A.

2010-09-01

388

Phase transformation and thermoelectric properties of bismuth-telluride nanowires  

E-print Network

materials, which can generate electricity while under a temperature gradient, have attracted much attention be used for a wide range of low-dimensional structures. Technologies for converting waste heat into useful electricity have become an important research topic in recent years.1­5 For this purpose, thermoelectric

Wu, Junqiao

389

Thermoelectrics, an environmentally-friendly source of electrical power  

Microsoft Academic Search

A thermoelectric generator is a unique heat engine in which charge carriers serve as the working fluid. It has no moving parts, is silent in operation and very reliable. However, its relatively low efficiency (typically around 5%) has restricted its use to specialised medical, military and space applications where cost is not a main consideration. During the past 10 years

D. M. Rowe

1999-01-01

390

Nonlinear thermoelectric response of quantum dots  

NASA Astrophysics Data System (ADS)

The thermoelectric transport properties of nanostructured devices continue to attract attention from theorists and experimentalist alike as the spatial confinement allows for a controlled approach to transport properties of correlated matter. Most of the existing work, however, focuses on thermoelectric transport in the linear regime despite the fact that the nonlinear conductance of correlated quantum dots has been studied in some detail throughout the last decade. To go beyond the linear response regime, we use a recently developed scheme [1], to address the low-energy behavior near the strong-coupling fixed point at finite bias voltage and finite temperature drop at the quantum dot. We test the reliability of the method against the numerical renormalization group [2] and determine the charge, energy, and heat current through the nanostructure. This allows us to determine the nonlinear transport coefficients, the entropy production, and the fate of the Wiedemann-Franz law in the non-thermal steady-state [3].[4pt] [1] E. Munoz et al, arXiv:1111.4076.[0pt] [2] L. Merker et al, in preparation.[0pt] [3] S. Kirchner, F. Zamani, and E. Munoz, in ``New Materials for Thermoelectric Applications: Theory and Experiment,'' Springer (2012).

Kirchner, Stefan; Zamani, Farzaneh; Munoz, Enrique; Merker, Lukas; Costi, Theo

2013-03-01

391

Thermal and thermoelectric properties of graphene.  

PubMed

The subject of thermal transport at the mesoscopic scale and in low-dimensional systems is interesting for both fundamental research and practical applications. As the first example of truly two-dimensional materials, graphene has exceptionally high thermal conductivity, and thus provides an ideal platform for the research. Here we review recent studies on thermal and thermoelectric properties of graphene, with an emphasis on experimental progresses. A general physical picture based on the Landauer transport formalism is introduced to understand underlying mechanisms. We show that the superior thermal conductivity of graphene is contributed not only by large ballistic thermal conductance but also by very long phonon mean free path (MFP). The long phonon MFP, explained by the low-dimensional nature and high sample purity of graphene, results in important isotope effects and size effects on thermal conduction. In terms of various scattering mechanisms in graphene, several approaches are suggested to control thermal conductivity. Among them, introducing rough boundaries and weakly-coupled interfaces are promising ways to suppress thermal conduction effectively. We also discuss the Seebeck effect of graphene. Graphene itself might not be a good thermoelectric material. However, the concepts developed by graphene research might be applied to improve thermoelectric performance of other materials. PMID:24610791

Xu, Yong; Li, Zuanyi; Duan, Wenhui

2014-06-12

392

Career Development in Generation X. Myths and Realities.  

ERIC Educational Resources Information Center

Several myths relate to the question of whether Generation X, the population cohort following the Baby Boomers, has different values, work ethics, and attitudes toward work and career development. The first myth is that individuals in Generation X are slackers, lacking career drive and ambition. The reality is that Generation X may just view the…

Lankard, Bettina A.

393

Thermoelectric properties of nanoporous Ge  

E-print Network

We computed thermoelectric properties of nanoporous Ge (np-Ge) with aligned pores along the [001] direction through a combined classical molecular dynamics and first-principles electronic structure approach. A significant ...

Lee, Joo-Hyoung

394

Bondability of Mg2Si element to Ni electrode using Al for thermoelectric modules  

NASA Astrophysics Data System (ADS)

The purpose of this study has been to develop a low cost bonding technique for thermoelectric Mg2Si/Si-Ge modules that provides reliable bonding. Aluminum was chosen as an alternative material to conventional silver alloy braze because of its cost advantage and bondability. The shear strength of an aluminum joint between a Mg2Si element and nickel electrode was 19 MPa. The generation capacity of a prototype Mg2Si/Si-Ge twin couple module was about 20% higher than that of a conventional Si-Ge/Si-Ge twin couple module at 923 K (?T = 620 K).

Tohei, Tomotake; Fujiwara, Shinichi; Jinushi, Takahiro; Ishijima, Zenzo

2014-08-01

395

Thermoelectricity from wasted heat of integrated circuits  

NASA Astrophysics Data System (ADS)

We demonstrate that waste heat from integrated circuits especially computer microprocessors can be recycled as valuable electricity to power up a portion of the circuitry or other important accessories such as on-chip cooling modules, etc. This gives a positive spin to a negative effect of ever increasing heat dissipation associated with increased power consumption aligned with shrinking down trend of transistor dimension. This concept can also be used as an important vehicle for self-powered systems-on-chip. We provide theoretical analysis supported by simulation data followed by experimental verification of on-chip thermoelectricity generation from dissipated (otherwise wasted) heat of a microprocessor.

Fahad, Hossain; Hasan, Md.; Li, Guodong; Hussain, Muhammad

2013-06-01

396

ZERO EMISSION POWER GENERATION TECHNOLOGY DEVELOPMENT  

SciTech Connect

Clean Energy Systems (CES) was previously funded by DOE's ''Vision 21'' program. This program provided a proof-of-concept demonstration that CES' novel gas generator (combustor) enabled production of electrical power from fossil fuels without pollution. CES has used current DOE funding for additional design study exercises which established the utility of the CES-cycle for retrofitting existing power plants for zero-emission operations and for incorporation in zero-emission, ''green field'' power plant concepts. DOE funding also helped define the suitability of existing steam turbine designs for use in the CES-cycle and explored the use of aero-derivative turbines for advanced power plant designs. This work is of interest to the California Energy Commission (CEC) and the Norwegian Ministry of Petroleum & Energy. California's air quality districts have significant non-attainment areas in which CES technology can help. CEC is currently funding a CES-cycle technology demonstration near Bakersfield, CA. The Norwegian government is supporting conceptual studies for a proposed 40 MW zero-emission power plant in Stavager, Norway which would use the CES-cycle. The latter project is called Zero-Emission Norwegian Gas (ZENG). In summary, current engineering studies: (1) supported engineering design of plant subsystems applicable for use with CES-cycle zero-emission power plants, and (2) documented the suitability and availability of steam turbines for use in CES-cycle power plants, with particular relevance to the Norwegian ZENG Project.

Ronald Bischoff; Stephen Doyle

2005-01-20

397

Technological assessment for developing new wind power generation systems  

Microsoft Academic Search

This paper describes the technological assessment employed in the development of new wind power generation systems, which facilitate stable, controllable energy supply systems in a diversified and competitive energy market. The concept of a new wind power generation system is presented and possible solutions to technical problems for the development of new wind power systems are discussed.

Guohong Wu; T. Minakawa; M. Goto; Y. Tada

2005-01-01

398

A continuum theory of thermoelectric bodies and effective properties of thermoelectric composites  

E-print Network

A continuum theory of thermoelectric bodies and effective properties of thermoelectric composites Science, 2012. Contents 1 Introduction 2 2 A continuum model for thermoelectric bodies 4 2.1 Experimental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 A constitutive model for thermoelectric materials . . . . . . . . . . . . . . . . . . . . 6 2

Liu, Liping

399

Developing the Next Generation of Geoscientists  

NASA Astrophysics Data System (ADS)

The Monitoring Seasons Through Global Learning Communities (Seasons and Biomes), an inquiry- and project- based program, works with K-12 teachers and their students worldwide to increase awareness and understanding of the Earth as a system, and the science process. Seasons and Biomes is one of four GLOBE (Global learning and Observations to Benefit the Environment, www.globe.gov) earth system science projects. Seasons and Biomes engage students in ongoing research investigations as way of learning science. We do this by conducting for teachers, professional development workshops that incorporate science content, best teaching practices (that include inquiry, integrating science with math, language and art, authentic assessments, concept mapping), a model for student scientific research, and an earth system science approach. Teachers learn and practice standardized measurement protocols developed by GLOBE in the following areas of investigations: atmosphere, hydrology, soils, phenology and land cover/biology, as well as those developed by Seasons and Biomes on ice seasonality (freeze-up and break-up of rivers and lakes), active layer/depth of soil freezing (frost tube), mosquitoes (larvae abundance and identification of mosquito vectors for malaria and dengue fever) and plant invasive species. They also learn how to enter data as well as access data on the GLOBE website. Teachers in turn teach and work with their students in doing authentic science, contribute data to ongoing research as well as conduct their own studies. During the workshops we also provide guidance and opportunity for early career scientists to share their research, work with teachers and mentor them as well as to develop measurement protocols pertinent to their research. Similarly we work with GLOBE Alumni, students who were in the GLOBE program when they were in primary and/or secondary schools and have graduated from college, yet are still very much inspired and dedicated to working with teachers and their students in conducting GLOBE activities and investigations. We offer the Seasons and Biomes PD workshops together with classroom implementation as University of Alaska course that teachers take for continuing education credits, for qualifying in core content areas of science or towards a graduate degree. Classes, small groups as well as individual students have conducted investigations and presented them at local, national and international science fairs, symposiums and conferences in addition to contributing observations/measurements to ongoing earth science investigations. Some teachers have also presented their work at national and international conferences. More than 1400 educators and scientists from 50 countries have participated in Seasons and Biomes reaching over 21,000 students. Results of program pre- and post-tests, teacher assessments as well as evidence submitted by teachers on student learning strongly suggest an increase in understanding of earth system science and the science process.

Sparrow, E. B.; Kopplin, M. R.

2012-12-01

400

Thermoelectric energy conversion using nanostructured materials  

E-print Network

High performance thermoelectric materials in a wide range of temperatures are essential to broaden the application spectrum of thermoelectric devices. This paper presents experiments on the power and efficiency characteristics ...

Chen, Gang

401

Investigation of thermoelectric properties of chalcogenide semiconductors from first principles  

NASA Astrophysics Data System (ADS)

In recent years, thermoelectric (TE) materials have attracted increasing interest due to their potential use in energy harvesting and conserving applications. A particular research effort has been focused on developing new materials with high ZT values, which are essential for TEs to be commercially applicable in refrigeration and waste heat recovery. Several promising bulk semiconductors have been reported by researchers so far. However, no satisfactorily high ZT value has been obtained. In a recent publication, [E. J. Skoug et al., Appl. Phys. Lett. 96, 181905 (2010)] reported very low lattice thermal conductivity on chalcogenide semiconductors and pointed out their potential for thermoelectricity. Following their findings, transport properties of these materials and some other promising bulk semiconductors, Bi2 Te3, SrTiO3, and Cu2 ZnSnSe4, were systematically analyzed using density functional and Boltzmann transport theories. In order to assess their capacity as thermoelectrics, a simple measure: `maximum' thermoelectric figure of merit, ZTm, was predicted at experimentally amenable doping levels. Results with higher ZTm values were obtained when compared to the current state of bulk thermoelectric materials. However, it is also found that reaching required ZT values for commonplace device applications with either these chalcogenides or the other semiconductors reported in our study is highly unlikely.

Sevik, C.; ?a??n, T.

2011-06-01

402

La 1?x Ca x MnO3 semiconducting nanostructures: morphology and thermoelectric properties  

PubMed Central

Semiconducting metallic oxides, especially perosvkite materials, are great candidates for thermoelectric applications due to several advantages over traditionally metallic alloys such as low production costs and high chemical stability at high temperatures. Nanostructuration can be the key to develop highly efficient thermoelectric materials. In this work, La 1?x Ca x MnO3 perosvkite nanostructures with Ca as a dopant have been synthesized by the hydrothermal method to be used in thermoelectric applications at room temperature. Several heat treatments have been made in all samples, leading to a change in their morphology and thermoelectric properties. The best thermoelectric efficiency has been obtained for a Ca content of x=0.5. The electrical conductivity and Seebeck coefficient are strongly related to the calcium content.

2014-01-01

403

Influence of electrical current variance and thermal resistances on optimum working conditions and geometry for thermoelectric energy harvesting  

NASA Astrophysics Data System (ADS)

Recent reports on enhanced thermoelectric figure of merits based on nanoscale effects have revived interest in potential applications of thermoelectric modules for waste heat recovery and distributed power generation. However, studies of optimized working conditions have not been thoroughly investigated. The majority of the previous studies on optimum load resistance for maximum power output or maximum efficiency assume temperatures at the ends of thermoelectric materials are known and constant. In reality, temperature should be determined by the energy conservation equations, which are functions of the load resistance, as well as the thermal resistances of the heat source, heat sink, and contact pads. This work exploits a numerical method to determine the actual temperature of thermoelectric materials, and optimum working conditions for thermoelectric energy harvesting are presented. The proposed model considers the effect of thermal resistances between a thermoelectric module and heat reservoirs, and the electrical current variation with respect to load resistance. The optimum condition for load resistance ratio was observed to occur at larger values than those obtained from traditional optimization work. Additionally, optimum geometry for a thermoelectric module is suggested for energy harvesting methods, where forced convection or oversized heat sinks cannot be used. Experimental results obtained from a commercial thermoelectric module are also presented to validate the proposed model. This work forms a basis to predict optimum working conditions in various thermoelectric energy harvesting applications.

Gomez, Miguel; Reid, Rachel; Ohara, Brandon; Lee, Hohyun

2013-05-01

404

On thermoelectric and pyroelectric energy harvesting  

Microsoft Academic Search

This paper deals with small-power energy harvesting from heat. It can be achieved using both thermoelectric and pyroelectric effects. In the first case, temperature gradients are necessary. The main difficulty of thermoelectric energy harvesting is imposing a large temperature gradient. This requires huge heat flows because of the limited surface heat exchanges and the large heat conductivity of thermoelectric materials.

Gael Sebald; Daniel Guyomar; Amen Agbossou

2009-01-01

405

Enhanced thermoelectric performance of rough silicon nanowires  

E-print Network

LETTERS Enhanced thermoelectric performance of rough silicon nanowires Allon I. Hochbaum1 *, Renkun, such that roughly 15 terawatts of heat is lost to the environment. Thermoelectric modules could potentially convert part of this low-grade waste heat to electricity. Their efficiency depends on the thermoelectric figure

Yang, Peidong

406

AbstractAbstract Improving efficiency of thermoelectric  

E-print Network

AbstractAbstract · Improving efficiency of thermoelectric energy conversion devices is a major-classical transport models used to predict ZT can effectively predict thermoelectric performance of bulk materials method proposed to couple quantum and scattering effects to predict thermoelectric performance. · NEGF

Walker, D. Greg

407

Thermoelectric phenomena via an interacting particle system  

E-print Network

Thermoelectric phenomena via an interacting particle system Christian Maes and Maarten H. van for thermoelectric phenomena in terms of an interacting particle system, a lattice electron gas dynamics, a standard reference is [1]. We present an interacting particle system for the standard thermoelectric

Maes, Christian

408

Projet TESEER Thermoelectric micro Energy Source  

E-print Network

Projet TESEER Thermoelectric micro Energy Source Enhanced by Electromagnetic Radiation Participants of silicon to be used as a hot-spot for a thermoelectric element. Applications also exists for PV cells) Thermoelectric micro Energy Source Enhanced by Electromagnetic Radiation Objectifs Le projet TESEER consiste

Baudoin, Geneviève

409

Spin-current-driven thermoelectric coating.  

PubMed

Energy harvesting technologies, which generate electricity from environmental energy, have been attracting great interest because of their potential to power ubiquitously deployed sensor networks and mobile electronics. Of these technologies, thermoelectric (TE) conversion is a particularly promising candidate, because it can directly generate electricity from the thermal energy that is available in various places. Here we show a novel TE concept based on the spin Seebeck effect, called 'spin-thermoelectric (STE) coating', which is characterized by a simple film structure, convenient scaling capability, and easy fabrication. The STE coating, with a 60-nm-thick bismuth-substituted yttrium iron garnet (Bi:YIG) film, is applied by means of a highly efficient process on a non-magnetic substrate. Notably, spin-current-driven TE conversion is successfully demonstrated under a temperature gradient perpendicular to such an ultrathin STE-coating layer (amounting to only 0.01% of the total sample thickness). We also show that the STE coating is applicable even on glass surfaces with amorphous structures. Such a versatile implementation of the TE function may pave the way for novel applications making full use of omnipresent heat. PMID:22706614

Kirihara, Akihiro; Uchida, Ken-ichi; Kajiwara, Yosuke; Ishida, Masahiko; Nakamura, Yasunobu; Manako, Takashi; Saitoh, Eiji; Yorozu, Shinichi

2012-08-01

410

Impact of novel thermoelectric materials on automotive applications  

NASA Astrophysics Data System (ADS)

Despite the fact that thermoelectric (TE) devices are compact, quiet, rugged, stable and very reliable, thermoelectrics have found only niche applications because they are also inefficient (less that 5% conversion efficiency is typical) and costly. The key to more widespread acceptance of thermoelectric is the development of materials that are capable of higher conversion efficiency, but other fundamental materials parameters play a role not less important to open to large applications and markets. In particular the automotive sector requires low materials density, materials made from widely-available pure elements with very large supply chains, non-toxicity of elements and potential compliance with REACH and RoHS obligations and low raw material cost combined with low manufacturing costs. The impact of novel TE materials on automotive application will be described focusing on promising nano magnesium silicide and skutterudites.

Brignone, Mauro; Ziggiotti, Alessandro

2012-06-01

411

Effect of Heat Exchanger Material and Fouling on Thermoelectric Exhaust Heat Recovery  

SciTech Connect

This study is conducted in an effort to better understand and improve the performance of thermoelectric heat recovery systems for automotive use. For this purpose an experimental investigation of thermoelectrics in contact with clean and fouled heat exchangers of different materials is performed. The thermoelectric devices are tested on a bench-scale thermoelectric heat recovery apparatus that simulates automotive exhaust. The thermoelectric apparatus consists of a series of thermoelectric generators contacting a hot-side and a cold-side heat exchanger. The thermoelectric devices are tested with two different hot-side heat exchanger materials, stainless steel and aluminum, and at a range of simulated exhaust gas flowrates (40 to 150 slpm), exhaust gas temperatures (240 C and 280 C), and coolant-side temperatures (40 C and 80 C). It is observed that for higher exhaust gas flowrates, thermoelectric power output increases while overall system efficiency decreases. Degradation of the effectiveness of the EGR-type heat exchangers over a period of driving is also simulated by exposing the heat exchangers to diesel engine exhaust under thermophoretic conditions to form a deposit layer. For the fouled EGR-type heat exchangers, power output and system efficiency is observed to be significantly lower for all conditions tested. The study found, however, that heat exchanger material is the dominant factor in the ability of the system to convert heat to electricity with thermoelectric generators. This finding is thought to be unique to the heat exchangers used for this study, and not a universal trend for all system configurations.

Love, Norman [University of Texas, El Paso; Szybist, James P [ORNL; Sluder, Scott [ORNL

2011-01-01

412

Development and Test of a Prototype 100MVA Superconducting Generator  

SciTech Connect

In 2002, General Electric and the US Department of Energy (DOE) entered into a cooperative agreement for the development of a commercialized 100 MVA generator using high temperature superconductors (HTS) in the field winding. The intent of the program was to: • Identify and develop technologies that would be needed for such a generator. • Develop conceptual designs for generators with ratings of 100 MVA and higher using HTS technology. • Perform proof of concept tests at the 1.5 MW level for GE’s proprietary warm iron rotor HTS generator concept. • Design, build, and test a prototype of a commercially viable 100 MVA generator that could be placed on the power grid. This report summarizes work performed during the program and is provided as one of the final program deliverables.

Fogarty, James M.; Bray, James W.

2007-05-25

413

Improved Thermoelectric Devices: Advanced Semiconductor Materials for Thermoelectric Devices  

SciTech Connect

Broad Funding Opportunity Announcement Project: Phononic Devices is working to recapture waste heat and convert it into usable electric power. To do this, the company is using thermoelectric devices, which are made from advanced semiconductor materials that convert heat into electricity or actively remove heat for refrigeration and cooling purposes. Thermoelectric devices resemble computer chips, and they manage heat by manipulating the direction of electrons at the nanoscale. These devices aren’t new, but they are currently too inefficient and expensive for widespread use. Phononic Devices is using a high-performance, cost-effective thermoelectric design that will improve the device’s efficiency and enable electronics manufacturers to more easily integrate them into their products.

None

2009-12-11

414

Numerical modeling of the transient behavior of a thermoelectric Electromagnetic Self-Induced Pump  

E-print Network

CHAPTERII THEORY OF PUMP OPERATION Pump and the system Thermoelectric voltage equation development . Back emf voltage equation development Magnetic field model development Pump head equation development Loop pressure drop calculations CHAPTER III... OF FIGURES Figure Page System flow schematic TEMSIP isomeric view Thermoelectric material with compliant pads TEMSIP cross section 10 Magnetic field in TEMSIP 12 Back emf illustration 15 Circuit diagram of electric current flow in the pump channel...

Djordjevic, Vladimir

2012-06-07

415

A study on thermoelectric properties of nanostructured bulk materials  

Microsoft Academic Search

Solid-state cooling and power generation based on thermoelectric effects are attractive for a wide range of applications in power generation, waste heat recovery, air-conditioning, and refrigeration. There have been persistent efforts on improving figure of merit (ZT) since 1950's, but the ZTs of dominant commercial bulk materials have been remained at ˜1. To improve ZT to a higher value, we

Bed Poudel

2007-01-01

416

Developments and trends in three-dimensional mesh generation  

NASA Technical Reports Server (NTRS)

An intense research effort over the last few years has produced several competing and apparently diverse methods for generating meshes. Recent progress is reviewed and the central themes are emphasized which form a solid foundation for future developments in mesh generation.

Baker, Timothy J.

1989-01-01

417

Fabrication of thermoelectric wire-matrix composites using electrodeposition  

NASA Astrophysics Data System (ADS)

Thermoelectric materials have potential applications in a wide range of heating and cooling systems. Thermoelectric coolers, for example, are small, lightweight, and silent. They have no moving parts or fluids. What hinders a broader use of thermoelectric materials is their inefficiency when compared to compressor based systems. Theoretical studies have shown that there is a possible enhancement in thermoelectric properties through quantum confinement of the material. Recent studies have attempted to show this enhancement through the fabrication of multilayers, quantum wires and coupled quantum dots. In this study, the fabrication of thermoelectric wire-matrix composites is attempted. Porous anodic aluminum oxide was chosen as the matrix material because of its high porosity, its uniform pore diameter, its low thermal conductivity, and its compatibility with current thermoelectric device structures. CoSb 3 was chosen as the wire material because of its potential to show an enhancement in thermoelectric properties above bulk values at diameters greater than other commonly used thermoelectric materials. Electrodeposition was chosen as the method of fabrication, as it best allowed for infiltration of wire material into the matrix. It was found, however, that cobalt and antimony could not be electrodeposited into the porous matrix from the same bath. Therefore a two bath, multilayer approach was used to fabricate wires, using a post anneal to form the CoSb3 phase. The formation of CoSb3 was demonstrated by depositing alternating layers of cobalt from a CoS0 47H2O bath and antimony from an Sb2O3 bath. Both baths were aqueous and contained a supporting electrolyte of citric acid and potassium citrate. Depositing the antimony layer for 22 times the duration of the cobalt deposition gave the correct stoichiometry in the multilayers. To form CoSb3, the multilayers were annealed in an antimony ambient at temperatures greater than 575°C. The post annealing was found to induce a shape change in the wires which appeared to have a sinusoidally varying radius with periodicity approximately equal to the multilayer period. This periodicity is not in a range where Rayleigh breakup would occur. Instead, there exists an 8.7% volume contraction on converting elemental cobalt and antimony to CoSb3. It is this contraction that is proposed as the cause of the observed wire breakup. Since periodicity and void fraction are both at the control of the experimentalist, different structures could be generated---from uniformly sized nanoparticles to continuous bead arrays. These structures are likely to exhibit unusual thermal and electrical transport behavior, which will have to be measured in the future.

Behnke, Joseph Frederick

418

INTRODUCTION The generation of polarity during metazoan development  

E-print Network

of development. Mutations in the gene lin-44 of the nematode Caenorhab- ditis elegans reverse both the relativeINTRODUCTION The generation of polarity during metazoan development requires the formation., 1992). During the development of the single-celled embryo of Drosophila melanogaster, anteroposterior

Kaufman, Glennis A.

419

Thermoelectric materials with filled skutterudite structure for thermoelectric devices  

NASA Technical Reports Server (NTRS)

A class of thermoelectric compounds based on the skutterudite structure with heavy filling atoms in the empty octants and substituting transition metals and main-group atoms. High Seebeck coefficients and low thermal conductivities are achieved in combination with large electrical conductivities in these filled skutterudites for large ZT values. Substituting and filling methods are disclosed to synthesize skutterudite compositions with desired thermoelectric properties. A melting and/or sintering process in combination with powder metallurgy techniques is used to fabricate these new materials.

Fleurial, Jean-Pierre (Inventor); Borshchevsky, Alex (Inventor); Caillat, Thierry (Inventor); Morelli, Donald T. (Inventor); Meisner, Gregory P. (Inventor)

2000-01-01

420

Thermoelectric materials with filled skutterudite structure for thermoelectric devices  

NASA Technical Reports Server (NTRS)

A class of thermoelectric compounds based on the skutterudite structure with heavy filling atoms in the empty octants and substituting transition metals and main-group atoms. High Seebeck coefficients and low thermal conductivities are achieved in combination with large electrical conductivities in these filled skutterudites for large ZT values. Substituting and filling methods are disclosed to synthesize skutterudite compositions with desired thermoelectric properties. A melting and/or sintering process in combination with powder metallurgy techniques is used to fabricate these new materials.

Fleurial, Jean-Pierre (Inventor); Borshchevsky, Alex (Inventor); Caillat, Thierry (Inventor); Morelli, Donald T. (Inventor); Meisner, Gregory P. (Inventor)

2002-01-01

421

Sublimation measurements and analysis of high temperature thermoelectric materials and devices  

NASA Technical Reports Server (NTRS)

High temperature thermoelectric device sublimation effects are compared for rare earth sulfides, selenides, and state-of-the-art Si-Ge alloys. Although rare earth calcogenides can potentially exhibit superior sublimation characteristics, the state-of-the-art Si-Ge alloy with silicon nitride sublimation-inhibitive coating has been tested to 1000 C. Attention is given to the ceramic electrolyte cells, forming within electrical and thermal insulation, which affect leakage conductance measurements in Si-Ge thermoelectric generators.

Shields, V.; Noon, L.

1983-01-01

422

Reliable contact fabrication on nanostructured Bi2Te3-based thermoelectric materials.  

PubMed

A cost-effective and reliable Ni-Au contact on nanostructured Bi2Te3-based alloys for a solar thermoelectric generator (STEG) is reported. The use of MPS SAMs creates a strong covalent binding and more nucleation sites with even distribution for electroplating contact electrodes on nanostructured thermoelectric materials. A reliable high-performance flat-panel STEG can be obtained by using this new method. PMID:23531997

Feng, Shien-Ping; Chang, Ya-Huei; Yang, Jian; Poudel, Bed; Yu, Bo; Ren, Zhifeng; Chen, Gang

2013-05-14

423

Thermoelectric effect in molecular electronics  

E-print Network

We provide a theoretical estimate of the thermoelectric current and voltage over a Phenyldithiol molecule. We also show that the thermoelectric voltage is (1) easy to analyze, (2) insensitive to the detailed coupling to the contacts, (3) large enough to be measured and (4) give valuable information, which is not readily accessible through other experiments, on the location of the Fermi energy relative to the molecular levels. The location of the Fermi-energy is poorly understood and controversial even though it is a central factor in determining the nature of conduction (n- or p-type). We also note that the thermoelectric voltage measured over Guanine molecules with an STM by Poler et al., indicate conduction through the HOMO level, i.e., p-type conduction.

M. Paulsson; S. Datta

2003-01-14

424

Thermoelectric refrigerator having improved temperature stabilization means  

DOEpatents

A control system for thermoelectric refrigerators is disclosed. The thermoelectric refrigerator includes at least one thermoelectric element that undergoes a first order change at a predetermined critical temperature. The element functions as a thermoelectric refrigerator element above the critical temperature, but discontinuously ceases to function as a thermoelectric refrigerator element below the critical temperature. One example of such an arrangement includes thermoelectric refrigerator elements which are superconductors. The transition temperature of one of the superconductor elements is selected as the temperature control point of the refrigerator. When the refrigerator attempts to cool below the point, the metals become superconductors losing their ability to perform as a thermoelectric refrigerator. An extremely accurate, first-order control is realized.

Falco, Charles M. (Woodridge, IL)

1982-01-01

425

Thermoelectric effects in Kondo-correlated quantum dots  

Microsoft Academic Search

In this letter we study thermoelectric effects in ultra-small quantum dots. We study the behaviour of the thermopower, Peltier coefficient and thermal conductance both in the sequential tunneling regime and in the regime where Kondo correlations develop. Both cases of linear response and non-equilibrium induced by strong temperature gradients are considered. The thermopower is a very sensitive tool to detect

Daniel Boese; Rosario Fazio

2001-01-01

426

Synthesis and thermoelectric properties of CoP(sub 3)  

NASA Technical Reports Server (NTRS)

In an effort to expand the range of operation for highly efficient, segmented thermoelectric unicouples currently being developed at JPL, skutterudite phosphides are being investigated as potential high temperature segments to supplement antimonide segments that limit the use of these unicouples at a hot-side temperature of about 873-973 K.

Shields, V. B.; Caillet, T.

2002-01-01

427

Fundamental study on alkali metal thermoelectric converter  

NASA Astrophysics Data System (ADS)

The alkali metal thermoelectric converter (AMTEC), which utilizes the sodium ion conducting beta-double prime-alumina, is a device for directly converting heat energy to electric energy. It is characterized by high conversion efficiencies of 20 to 40 percent, high power densities of 1 W/sq cm, no moving parts, low maintenance requirements, high durability, and efficiency independent of size. Because of these merits, AMTEC is one of the most promising candidates for dispersed small-scale power stations, remote power stations, and aerospace power systems. In this paper, the results of theoretical and experimental studies on AMTEC power generating characteristics, internal electrical resistances of single cells, and system analysis of AMTEC power-generating systems are reported.

Masuda, Toshihisa

1989-11-01

428

A Model for Predicting Thermoelectric Properties of Bi2Te3  

NASA Technical Reports Server (NTRS)

A parameterized orthogonal tight-binding mathematical model of the quantum electronic structure of the bismuth telluride molecule has been devised for use in conjunction with a semiclassical transport model in predicting the thermoelectric properties of doped bismuth telluride. This model is expected to be useful in designing and analyzing Bi2Te3 thermoelectric devices, including ones that contain such nano - structures as quantum wells and wires. In addition, the understanding gained in the use of this model can be expected to lead to the development of better models that could be useful for developing other thermoelectric materials and devices having enhanced thermoelectric properties. Bi2Te3 is one of the best bulk thermoelectric materials and is widely used in commercial thermoelectric devices. Most prior theoretical studies of the thermoelectric properties of Bi2Te3 have involved either continuum models or ab-initio models. Continuum models are computationally very efficient, but do not account for atomic-level effects. Ab-initio models are atomistic by definition, but do not scale well in that computation times increase excessively with increasing numbers of atoms. The present tight-binding model bridges the gap between the well-scalable but non-atomistic continuum models and the atomistic but poorly scalable ab-initio models: The present tight-binding model is atomistic, yet also computationally efficient because of the reduced (relative to an ab-initio model) number of basis orbitals and flexible parameterization of the Hamiltonian.

Lee, Seungwon; VonAllmen, Paul

2009-01-01

429

Design and assembly of nanostructured complex metal oxide materials for the construction of batteries and thermoelectric devices  

NASA Astrophysics Data System (ADS)

Thermoelectric devices and lithium-ion batteries are among the fastest growing energy technologies. Thermoelectric devices generate energy from waste heat, whereas lithium-ion batteries store energy for use in commercial applications. Two different topics are bound with a common thread in this thesis - nanotechnology! In fact, nanostructuring is a more preferred term for the approach I have taken herein. Another commonality between these two topics is the material system I have used to prove my hypotheses - complex metal oxides. Complex metal oxides can be used for both energy generation and storage as they are stable at high temperatures, are benign and inexpensive, and are chemically stable. . Nevertheless, complex metal oxide-based materials have drawbacks when they are used in thermoelectric devices. Since they have high thermal conductivities and low power factors, they have lower thermoelectric figures of merit (ZT). This affects their performance as thermoelectric materials. Nanostructuring can solve this critical problem as thermal conductivity, electrical conductivity and Seebeck coefficient become quasi-independent of each other under these conditions. However, oxide-based materials have proven to be greatly recalcitrant to forming nanostructures when traditional synthetic methods such as solid-state reactions have been employed. Solid-state reactions usually proceed at extremely high temperatures that are not particularly conducive to forming nanostructures. The first part of this thesis presents novel solution-based synthetic methods that were developed in order to produce novel nanostructured complex metal oxides. Typical structures include nanowires. The second part of this thesis extends this methodology to study the effect of nanostructuring on the thermal conductivity of strontium titanate (SrTiO3), a promising high temperature thermoelectric material. Ultrathin nanowires of SrTiO3 were synthesized using a novel hydrothermal reaction. These ultrathin nanowires were compressed into a `nanostructured' bulk pellet through spark plasma sintering. The thermal conductivity measured on the nanostructur