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1

Design and development of thermoelectric generator  

NASA Astrophysics Data System (ADS)

In this paper we discuss the fabrication, working and characteristics of a thermoelectric generator made up of p and n type semiconductor materials. The device consists of Fe0.2Co3.8Sb11.5Te0.5 (zT = 1.04 at 818 K) as the n-type and Zn4Sb3 (zT=0.8 at 550 K) as the p-type material synthesized by vacuum hot press method. Carbon paste has been used to join the semiconductor legs to metal (Molybdenum) electrodes to reduce the contact resistance. The multi-couple (4 legs) generator results a maximum output power of 1.083 mW at a temperature difference of 240 K between the hot and cold sides. In this investigation, an I-V characteristic, maximum output power of the thermoelectric module is presented. The efficiency of thermoelectric module is obtained as ? = 0.273 %.

Prem Kumar, D. S.; Mahajan, Ishan Vardhan; Anbalagan, R.; Mallik, Ramesh Chandra

2014-04-01

2

Manportable Thermoelectric Generator.  

National Technical Information Service (NTIS)

The report describes the design, fabrication, and test of the 120 Watt Manportable Thermoelectric Generator (exploratory development model). This portable device is comprised of five functional subsystems: thermoelectric converter, liquid fuel burner, ele...

K. Magnuson E. Pitcher P. Stroom

1974-01-01

3

Thermoelectric Generator  

NASA Technical Reports Server (NTRS)

Small modular alkali metal thermoelectric generator with no moving parts directly converts heat to electrical energy with efficiency of 20 to 40 percent. Unit uses closed regenerative electrochemical concentration cell based on sodium-ion conductor beta alumina.

Cole, T.

1985-01-01

4

Progress in the development of high efficiency segmented thermoelectric generators  

NASA Astrophysics Data System (ADS)

The integration of new more efficient thermoelectric materials developed at the Jet Propulsion Laboratory into a new high performance segmented thermoelectric generator has been reported earlier. Progress in the development of this new segmented thermoelectric generator is reported in this paper. This generator would operate over a large temperature difference (300-973 K) and uses novel segmented legs based on a combination of state-of-the-art thermoelectric materials and p-type Zn4-xCdxSb3 alloys, p-type CeFe4Sb12-based alloys and n-type CoSb3-based alloys. An increase in the thermoelectric materials conversion efficiency of about 60% is expected compared to Bi2Te3- and PbTe-based generators. A computer program was written to optimize the thermal efficiency of the device. The optimal geometry, power output, efficiency and other properties of the generator were calculated and are presented. In addition results of bonding studies between Zn4Sb3 and Bi0.4Sb1.6Te3 are reported and discussed.

Caillat, T.; Fleurial, J.-P.; Snyder, G. J.; Zoltan, A.; Zoltan, D.; Borshchevsky, A.

1999-01-01

5

Radioisotope thermoelectric generator transportation system subsystem 143 software development plan  

NASA Astrophysics Data System (ADS)

This plan describes the activities to be performed and the controls to be applied to the process of specifying, developing, and qualifying the data acquisition software for the Radioisotope Thermoelectric Generator (RTG) Transportation System Subsystem 143 Instrumentation and Data Acquisition System (IDAS). This plan will serve as a software quality assurance plan, a verification and validation (V and V) plan, and a configuration management plan.

King, D. A.

1994-11-01

6

Thermally cascaded thermoelectric generator  

NASA Technical Reports Server (NTRS)

High efficiency thermoelectric generator utilizes a high-temperature thermoelectric material in thermal series with a low-temperature material. A thermally cascaded generator increases system efficiency.

Flaherty, R.

1970-01-01

7

Advanced Thermoelectric Materials for Radioisotope Thermoelectric Generators  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the progress and processes involved in creating new and advanced thermoelectric materials to be used in the design of new radioiootope thermoelectric generators (RTGs). In a program with Department of Energy, NASA is working to develop the next generation of RTGs, that will provide significant benefits for deep space missions that NASA will perform. These RTG's are planned to be capable of delivering up to 17% system efficiency and over 12 W/kg specific power. The thermoelectric materials being developed are an important step in this process.

Caillat, Thierry; Hunag, C.-K.; Cheng, S.; Chi, S. C.; Gogna, P.; Paik, J.; Ravi, V.; Firdosy, S.; Ewell, R.

2008-01-01

8

Thermoelectric Coolers and Generators.  

National Technical Information Service (NTIS)

The book discusses questions concerning the theory, design, rating, and use of thermoelectric coolers and generators. It shows the influence of the special features of thermoelectric processes in combination with electrotechnical and heat engineering proc...

I. V. Zorin Z. Y. Zorina

1975-01-01

9

Thermoelectric power generation for battery charging  

Microsoft Academic Search

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 converter system, powered from butane

Mahmudur Rahman; Roger Shuttleworth

1995-01-01

10

Recent developments in thermoelectric materials  

Microsoft Academic Search

The increased activity in attempts to develop improved thermoelectric semiconductors for use in the direct conversion of heat into electrical energy results mostly from research sponsorship by the US Military and NASA. Thermoelectric generators have no moving parts and are difficult to detect by visual, aural or thermal infrared means. Fossil multifuelled thermoelectric generators are the leading candidates for replacing

D. M. Rowe

1986-01-01

11

Solar Thermoelectric Generators.  

National Technical Information Service (NTIS)

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 techno...

1977-01-01

12

Development and testing of a domestic woodstove thermoelectric generator with natural convection cooling  

Microsoft Academic Search

A thermoelectric generator was fitted to the side of a domestic woodstove. The generator was driven using one or more thermoelectric modules designed to give significant power at a reasonable cost. The thermoelectric generator was air cooled by natural convection using a commercially available heat sink. Testing was undertaken under a controlled woodstove firing rate and temperatures, and open circuit

Rida Y. Nuwayhid; Alan Shihadeh; Nesreen Ghaddar

2005-01-01

13

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

14

120 watt thermoelectric generator  

Microsoft Academic Search

The Manpack, a 120-W portable liquid-fueled thermoelectric generator, consists of a thermoelectric converter, multiliquid fuel combustor, forced-air cooling, and electronic microprocessor control. The Manpack can operate continuously for 8 hours (with the operation capacity extendable by the use of an auxiliary fuel connection), has an operational range of -40 C to +50 C, and an adjustable output of 24 to

Daryl K. Marling

1986-01-01

15

Development of a High Efficiency Thermoelectric Unicouple for Power Generation Applications  

NASA Technical Reports Server (NTRS)

To achieve high thermal-to-electric energy conversion efficiency, it is desirable to operate thermoelectric generator devices over large temperature gradients and also to maximize the performance of the thermoelectric materials used to build the devices.

Caillat, T.; Fleurial, J-P.; Synder, G.; Zoltan, A.; Zoltan, D.; Borshchevsky, A.

1999-01-01

16

Modular Isotopic Thermoelectric Generator.  

National Technical Information Service (NTIS)

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 mater...

A. Schock

2011-01-01

17

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

18

Development of advanced thermoelectric materials  

NASA Technical Reports Server (NTRS)

The development of an advanced thermoelectric material for radioisotope thermoelectric generator (RTG) applications is reported. A number of materials were explored. The bulk of the effort, however, was devoted to improving silicon germanium alloys by the addition of gallium phosphide, the synthesis and evaluation of lanthanum chrome sulfide and the formulation of various mixtures of lanthanum sulfide and chrome sulfide. It is found that each of these materials exhibits promise as a thermoelectric material.

1984-01-01

19

Ground Power Thermoelectric Generator Investigation.  

National Technical Information Service (NTIS)

This report describes the development work on high power density thermoelectric elements and encompasses thermoelectric element design and analysis, element development and fabrication, and element operation. The element design and analysis portion of the...

R. Magladry T. H. Cox L. J. Gagola H. M. Kreitz M. N. Ross

1966-01-01

20

Development of a high efficiency thermoelectric unicouple for power generation applications  

Microsoft Academic Search

To achieve high thermal-to-electric energy conversion efficiency, it is desirable to operate thermoelectric generator devices over large temperature gradients and also to maximize the performance of the thermoelectric materials used to build the devices. However, no single thermoelectric material is suitable for use over a very wide range of temperatures (~300-1000 K). It is therefore necessary to use different materials

T. Caillat; J.-P. Fleurial; G. N. Snyder; A. Zoltan; D. Zoltan; A. Borshchevsky

1999-01-01

21

Ground Power Thermoelectric Generator Module.  

National Technical Information Service (NTIS)

The report describes the recent work on high power density thermoelectric elements and encompasses thermoelectric design and analysis, element development and fabrication and element operations. Sixty-two elements were fabricated and tested and 59 were an...

G. Zindler R. Magladry

1967-01-01

22

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, John D. (Eaton's Neck, NY); El-Genk, Mohamed S. (Albuquerque, NM)

1998-01-01

23

Superconducting thermoelectric generator  

DOEpatents

An apparatus and method for producing electricity from heat is disclosed. 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. 4 figs.

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

1998-05-05

24

Recent concepts in thermoelectric power generation  

Microsoft Academic Search

The development of economic thermoelectric generators for waste heat recovery has become an increasing research focus over the past a few years. Traditionally, attempts to improve their economic viability have concentrated primarily on improving the conversion efficiency by increasing the figure-of-merit of thermoelectric materials, with only marginal successes. This paper explores the possibilities and implications of alternative approaches in an

Gao Min; D. M. Rowe

2002-01-01

25

Thermodynamic analysis of thermoelectric generator  

SciTech Connect

The aim of this research has been to investigate the role of the second law in thermoelectric phenomena. Considering the thermoelectric generator as a heat engine cycle process, the Kelvin relations for the thermoelectric circuit are derived from the energy balance and from the second law without using reversibility or equilibrium assumptions. A new formula has been derived for the thermal efficiency of the thermoelectric generator, also taking into account Thomson heat. An equation for maximum efficiency is derived and a representative numerical example of this equation is presented.

Lampinen, M.J. (Helsinki University of Technology, Department of Energy Engineering, Otakaari 4, SF-02150 Espoo, Finland (FI))

1991-04-15

26

The Next Generation Thermoelectric Materials  

NASA Astrophysics Data System (ADS)

Recently there been renewed interest in materials for thermoelectric refrigeration and power generation applications.^1, 2 Many new materials and new classes of materials are being investigated for potential thermoelectric applications. An introduction to thermoelectric refrigeration and power generation, the advantages and disadvantages and potential applications will be discussed. An overview of some of the current thermoelectric materials under investigation and the criteria for selection of new materials will be given. To be promising as a thermoelectric material, a material must have a high Seebeck coefficient, ?, high electrical conductivity, ?, and a low thermal conductivity, ?. These parameters go into the material's dimensionless figure of merit ZT = ? ^2?T/?. Our research at Clemson is focused on a number of new materials, quasicrystals and pentatelluride materials, which show promise for thermoelectrics and these systems will be briefly discussed. Demonstrations of thermoelectric devices will be shown and discussed. 1.) Thermoelectric Materials: New Directions and Approaches, MRS Volumes 478 and 545, edited by Terry M. Tritt et. al. 2.) G. Mahan, B. Sales and J. Sharp, Physics Today, March 50, 42, 1997

Tritt, Terry M.

1999-11-01

27

Status and future prospects on the development of thermoelectric power generation systems utilizing combustion heat from municipal solid waste  

Microsoft Academic Search

The characteristics of combustion heat from the municipal solid waste are fitted for a large-scale application of thermoelectric power generation potentially. The status and future prospects of thermoelectric power generation systems to recover electricity from this heat source in Japan are reviewed and discussed. Experimental results on three different types of small-scale (500 W class) thermoelectric power generation systems installed

T. Kajikawa

1997-01-01

28

100 Watt Thermoelectric Generator.  

National Technical Information Service (NTIS)

A number of modifications were made on the thermoelectric couple design. These modifications were prompted by the module power output performance obtained during the last quarter. A number of modules incorporating the previous design were operated for ext...

H. P. Van Heyst O. H. Schade

1965-01-01

29

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

30

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

31

Thermoelectric Generator for a Stationary Diesel Plant  

NASA Astrophysics Data System (ADS)

This paper describes the development and testing of a thermoelectric generator (TEG) using the exhaust heat of a 50-kW stationary diesel power plant. The generator consists of six units that represent primary generators for each diesel engine cylinder. Each primary generator comprises five sections with gas heat exchangers, thermoelectric modules, and liquid heat exchangers. The sections were optimized for the exhaust gas operating temperatures. The generator electric power was 2.1 kW at rated power of 2.2 kW, corresponding to 4.4% of the diesel plant electric power.

Anatychuk, L. I.; Rozver, Yu. Yu.; Velichuk, D. D.

2011-05-01

32

Thermoelectric power generation system optimization studies  

NASA Astrophysics Data System (ADS)

A significant amount of energy we consume each year is rejected as waste heat to the ambient. Conservative estimates place the quantity of energy wasted at about 70%. Converting the waste heat into electrical power would be convenient and effective for a number of primary and secondary applications. A viable solution for converting waste heat into electrical energy is to use thermoelectric power conversion. Thermoelectric power generation is based on solid state technology with no moving parts and works on the principle of Seebeck effect. In this work a thermoelectric generator (TEG) system simulator was developed to perform various parametric and system optimization studies. Optimization studies were performed to determine the effect of system size, exhaust and coolant ow conditions, and thermoelectric material on the net gains produced by the TEG system and on the optimum TEG system design. A sports utility vehicle was used as a case study for the application of TEG in mobile systems.

Karri, Madhav A.

33

Economic Radioisotope Thermoelectric Generator (RTG) Study. Volume II. Development Plan. Final Report.  

National Technical Information Service (NTIS)

The objectives of this study were: (1) to develop and evaluate an ERTG design for a high power, Curium-244 fueled system based on the tubular thermoelectric module technology; (2) to prepare a program plan for the development of a flight qualified ERTG; a...

1973-01-01

34

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

Microsoft Academic Search

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

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

1992-01-01

35

Modelling heat exchangers for thermoelectric generators  

Microsoft Academic Search

In order to further studies on thermoelectric generators, an analysis of the influence of fluid flow rate, heat exchanger geometry, fluid properties and inlet temperatures on the power supplied by the thermoelectric generator has been done. Different expressions and graphs showing this influence are shown in this paper, in order to give some practical guidelines for the thermoelectric generators design.

J. Esarte; G. Min; D. M. Rowe

2001-01-01

36

Thermoelectric Generators on Living Beings  

Microsoft Academic Search

Unobtrusive scavenging of the heat dissipated by living beings through using thermoelectric generators (TEGs) on their skin is discussed in general. Targeting at such application of TEGs on man the measured relevant thermal features of human beings are reported next. As pointed out in the paper, the specific matching conditions of a TEG with the ambient should be satisfied to

V. Leonov; R. J. M. Vullers

37

Power generation of a thermoelectric generator with phase change materials  

NASA Astrophysics Data System (ADS)

In this paper, a thermoelectric generator that embeds phase change materials for wasted heat energy harvesting is proposed. The proposed thermoelectric generator embeds phase change materials in its device structure. The phase change materials store large amounts of heat energy using the latent heat of fusion. When the heat source contacts the thermoelectric generator, dissipated heat from the heat source is stored in the phase change materials. When the heat source is removed from the thermoelectric generator, the output power of the thermoelectric generator slowly decreases, while the output power of conventional thermoelectric generators decreases rapidly without the heat source. The additional air layer in the proposed thermoelectric generator disturbs the heat dissipation from the phase change materials, so the thermoelectric generator can maintain the power generation for longer without a heat source. The experimental results for the thermoelectric generator fabricated clearly show the latent heat effect of the phase change materials and the embedded air layer.

Jo, Sung-Eun; Kim, Myoung-Soo; Kim, Min-Ki; Kim, Yong-Jun

2013-11-01

38

Safety monitoring system for radioisotope thermoelectric generators  

NASA Technical Reports Server (NTRS)

System alerts personnel of hazards which may develop while they are performing tests on radioisotope thermoelectric generator (RTG). Remedial action is initiated to minimize damage. Five operating conditions are monitored: hot junction temperature, cold junction temperature, thermal shroud coolant flow, vacuum in test chamber, and alpha radiation.

Zoltan, A.

1973-01-01

39

Optimal operation of thermoelectric cooler driven by solar thermoelectric generator  

Microsoft Academic Search

The possibility of using a solar thermoelectric generator (TEG) to drive a small thermoelectric cooler (TEC) is studied in the present work. The study includes the theory of both the TEG and the TEC, giving special consideration to determination of the number of TEG modules required to power the TEC to achieve the best performance of the TEG–TEC system all

N. M. Khattab; E. T. El Shenawy

2006-01-01

40

Development of the data base for a degradation model of a selenide RTG. [Radioisotope Thermoelectric Generator  

NASA Technical Reports Server (NTRS)

The paper is concerned with the evaluation of the materials used in a selenide radioisotope thermoelectric generator (RTG). These materials are composed of n-type gadolinium selenide and n-type copper selenide. A three-fold evaluation approach is being used: (1) the study of the rate of change of the thermal conductivity of the material, (2) the investigation of the long-term stability of the material's Seebeck voltage and electrical resistivity under current and temperature gradient conditions, and (3) determination of the physical behavior and compatibility of the material with surrounding insulation at elevated temperatures. Programmatically, the third category of characteristic evaluation is being emphasized.

Stapfer, G.; Truscello, V. C.

1977-01-01

41

Thermoelectric cooling and power generation  

PubMed

In a typical thermoelectric device, a junction is formed from two different conducting materials, one containing positive charge carriers (holes) and the other negative charge carriers (electrons). When an electric current is passed in the appropriate direction through the junction, both types of charge carriers move away from the junction and convey heat away, thus cooling the junction. Similarly, a heat source at the junction causes carriers to flow away from the junction, making an electrical generator. Such devices have the advantage of containing no moving parts, but low efficiencies have limited their use to specialty applications, such as cooling laser diodes. The principles of thermoelectric devices are reviewed and strategies for increasing the efficiency of novel materials are explored. Improved materials would not only help to cool advanced electronics but could also provide energy benefits in refrigeration and when using waste heat to generate electrical power. PMID:10426986

DiSalvo

1999-07-30

42

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

43

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

44

Lead telluride as a thermoelectric material for thermoelectric power generation  

Microsoft Academic Search

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 900K. PbTe has a high melting point, good chemical stability, low vapor pressure and

Z. H. Dughaish

2002-01-01

45

Thermoelectric materials development  

NASA Technical Reports Server (NTRS)

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. 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 CoSb3 and IrSb3, and RuSb2Te, and (2) CeFe(4-x)Sb12 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(4-x)Ru(x)Sb12 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(4-x)Ru(x)Sb12 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.

1998-01-01

46

Thermoelectric generator apparatus and operation method  

SciTech Connect

A method of operating a thermoelectric generator includes: cyclically producing increasing then decreasing temperature differences in the thermoelectric material of the generator; and generating a cyclically increasing then decreasing electrical generator output signal, in response to such temperature differences, to transmit electrical power generated by the generator from the generator. Part of the thermoelectric material reaches temperatures substantially above the melting temperature of the material. The thermoelectric material of the generator forms a part of a closed electrical loop about a transformer core so that the inductor voltage for the loop serves as the output signal of the generator. A thermoelectric generator, which can be driven by the described method of operation, incorporates fins into a thermopile to conduct heat toward or away from the alternating spaces between adjacent layers of different types of thermoelectric material. The fins extend from between adjacent layers, so that they can also conduct electrical current between such layers, perpendicularly to the direction of stacking of the layers. The exhaust from an internal combustion engine can be employed to drive the thermoelectric generator, and, also, to act as a driver for a thermoelectric generator in accordance with the method of operation initially described.

Lowther, F.E.

1984-07-31

47

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

48

Radioisotope thermoelectric generators for implanted pacemakers  

Microsoft Academic Search

This paper discusses the development and application of long-life lithium batteries and the problems associated with miniature radioisotope thermoelectric generators (RITEG) with service lives of 10 years or longer. On eof the main problems encountered when devising a radioisotope heat source (RHS) for an RITEG is to obtain biomedical ²³⁸PuOâ with a specific neutron yield of 3.10³-4.10³ (g \\/SUP .\\/

A. A. Pustovalov; V. P. Shapovalov; A. V. Bovin; V. I. Fedorets

1986-01-01

49

Development of a Thermal Buffering Device to Cope with Temperature Fluctuations for a Thermoelectric Power Generator  

NASA Astrophysics Data System (ADS)

To stabilize the heat input to a thermoelectric generator (TEG) and protect it from large temperature fluctuations, a thermal buffering device (TBD) was fabricated and examined using a typical Bi-Te TEG module and a brand-new Mg2Si TEG module. The TBD comprises two adjoining heat storage containers, each containing different alloys, which can be optimized for the temperature range of the TEG. The combination of two alloys in series diminishes the thermal fluctuations, stabilizing the heat input to the TEG module. This is achieved by having two metallic materials with large enthalpies of fusion that can be placed between the heat source and the TEG. The combination of the two alloys can be optimized for the temperature ranges of Bi-Te, Pb-Te, or Co-Sb. For the Bi-Te TEG, 15Al-85Zn and 30Sn-70Zn alloys were used for the heat source side and the TEG side, respectively. The corresponding alloys for the Mg2Si TEG were 20Ni-80Al and 7Si-93Al. With the use of a TBD, the Bi-Te TEG exhibited no notable damage even in the rather high temperature range beyond ˜573 K. For the Mg2Si TEG, no operational damage of the Mg2Si TEG module was observed even with a temperature of 1020 K.

Mizuno, Kuniaki; Sawada, Kazunori; Nemoto, Takashi; Iida, Tsutomu

2012-06-01

50

Thermal analysis of thermoelectric power generator; Including thermal stresses  

NASA Astrophysics Data System (ADS)

In recent years, the energy demand is increasing leads to use and utilization of clean energy becomes target of countries all over the world. Thermoelectric generator is one type of clean energy generators which is a solid-state device that converts heat energy into electrical energy through the Seebeck effect. With availability of, heat from different sources such as solar energy and waste energy from systems, thermoelectric research becomes important research topic and researchers investigates efficient means of generating electricity from thermoelectric generators. One of the important problems with a thermoelectric is development of high thermal stresses due to formation of temperature gradient across the thermoelectric generator. High thermal stress causes device failure through cracks or fractures and these short comings may reduce the efficiency or totally fail the device. In this thesis work, thermodynamic efficiency and thermal stresses developed in thermoelectric generator are analyzed numerically. The bismuth telluride (Bi2Te3) properties are used in simulation. Stress levels in thermoelectric device pins are computed for various pin geometric configurations. MASTER.

Al-Merbati, Abdulrahman Salman

51

Approach to the Practical Use of Thermoelectric Power Generation  

NASA Astrophysics Data System (ADS)

The results of research and development in the Japanese national project “Development for Advanced Thermoelectric Conversion Systems” are summarized, and the approaches to practical use of advanced thermoelectric modules and power generation systems are presented. The 5-year national project was successfully completed in March 2007. Three kinds of high- efficiency cascaded thermoelectric modules and two kinds of innovative Bi-Te thermoelectric modules were successfully developed. Heat cycle tests for three types of modules were also completed. Moreover, four types of advanced thermoelectric power generation systems were experimentally demonstrated for recovery of waste heat from the industrial and private sectors. In order to proceed further, thermoelectric power generation systems using practical heat sources were followed after installation of the developed modules. In parallel, various approaches for practical use by private companies, as well as plans for the next-phase project by the National Institute of Advanced Industrial Science and Technology (AIST) and the Engineering Advancement Association (ENAA), were also followed. The scenarios to proceed to the commercial phase of thermoelectric power generation are discussed on the basis of the results of the national project.

Kajikawa, Takenobu

2009-07-01

52

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

53

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

54

Power Conditioner with Variable Switching Control for Thermoelectric Generator Systems  

NASA Astrophysics Data System (ADS)

A thermoelectric (TE) power conditioner maintaining high efficiency over a wide input power range has been developed. Variable switching frequency operation is shown to give an improvement in efficient operating range. The input range showing more than 90% conversion efficiency is expanded to more than 25% by introducing a low-power controller circuit and variable switching frequency control. The TE power conditioner showed excellent response against a change in thermoelectric generator (TEG) output and load, making it suitable for automotive applications.

Nagayoshi, Hiroshi; Maiwa, Hiroshi; Kajikawa, Takenobu

2013-07-01

55

Module Design Method in Thermoelectric Generation System with Environmental Load Evaluation  

NASA Astrophysics Data System (ADS)

This paper describes a method to design a thermoelectric module in the thermoelectric generation system with an environmental load evaluation. We analyzed an energy ratio defined as the electrical output over the equivalent electrical input and life cycle CO2 emissions for each module design in the thermoelectric generation system. It was found that the optimum module design could be decided uniquely by the evaluation of the energy ratio or life CO2 emissions in the thermoelectric generation system. And by applying the optimum module design in the system, the thermoelectric generation system with a low environmental load could be designed and developed.

Hori, Yasuhiko; Ito, Tetsuo

56

Computer modeling of thermoelectric generator performance  

NASA Technical Reports Server (NTRS)

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

Chmielewski, A. B.; Shields, V.

1982-01-01

57

Thermoelectric generator cooling system and method of control  

DOEpatents

An apparatus is provided that includes a thermoelectric generator and an exhaust gas system operatively connected to the thermoelectric generator to heat a portion of the thermoelectric generator with exhaust gas flow through the thermoelectric generator. A coolant system is operatively connected to the thermoelectric generator to cool another portion of the thermoelectric generator with coolant flow through the thermoelectric generator. At least one valve is controllable to cause the coolant flow through the thermoelectric generator in a direction that opposes a direction of the exhaust gas flow under a first set of operating conditions and to cause the coolant flow through the thermoelectric generator in the direction of exhaust gas flow under a second set of operating conditions.

Prior, Gregory P; Meisner, Gregory P; Glassford, Daniel B

2012-10-16

58

Graded and stacked thermoelectric generators—numerical description and maximisation of output power  

Microsoft Academic Search

Large temperature differences applied to thermoelectric generators require that the variations of all material properties with temperature are included in a numerical description of their performance. A finite element algorithm is developed to calculate the temperature field in a thermoelectric device and concomitantly its thermoelectric performance under operation conditions. Spatially varying the composition of material or the doping concentration allows

L. Helmers; E. Müller; J. Schilz; W. A. Kaysser

1998-01-01

59

Thermoelectric power generator with intermediate loop  

DOEpatents

A thermoelectric power generator is disclosed for use to generate electrical power from heat, typically waste heat. An intermediate heat transfer loop forms a part of the system to permit added control and adjustability in the system. This allows the thermoelectric power generator to more effectively and efficiently generate power in the face of dynamically varying temperatures and heat flux conditions, such as where the heat source is the exhaust of an automobile, or any other heat source with dynamic temperature and heat flux conditions.

Bel,; Lon E. (Altadena, CA); Crane, Douglas Todd (Pasadena, CA)

2009-10-27

60

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)

2002-01-01

61

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

62

General-purpose heat source: Research and development program. Radioisotope thermoelectric generator impact tests: RTG-1 and RTG-2  

SciTech Connect

The General-Purpose Heat Source (GPHS) 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. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure.

Reimus, M.A.H.; Hinckley, J.E.; George, T.G.

1996-07-01

63

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

64

Solar PV-thermoelectric generator hybrid system: case studies  

Microsoft Academic Search

A solar photovoltaic (PV) thermoelectric generator (TEG) hybrid system combines the economics of a solar photovoltaic system with the reliability and heating capability of a thermoelectric generator system. The solar system provides power during seasons with abundant sunshine while the thermoelectric generator system provides power and heat as required during seasons with insufficient solar insolation or during extended periods of

G. Moore; W. Peterson

1988-01-01

65

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

66

The thermoelectric generator test program at JPL.  

NASA Technical Reports Server (NTRS)

Discussion of the test results and analysis performed on data obtained from eight thermoelectric generators exhibiting a total combined operating time of about 21 years. Three (3) SNAP-19 type generators are discussed. Generator SN-20, the engineering model of the units presently operating on the Nimbus S/C, has been in operation for over 4 years and has shown drastic degradation after losing the internal cover gas. Generator SN-21, with more than four years of operating time, is operated in an air environment. The performance of this generator appears predictable and stable. For the last 2 years of operation generator degradation has been negligible. Generator SN-31, which utilizes the TAGS material for the P thermoelectric leg, is similar in design to the units to be used on the Pioneer S/C and has operated for over two years in an all-argon atmosphere.

Stapfer, G.; Rouklove, P.

1972-01-01

67

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

68

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

69

Titanium nitride 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 of titanium nitride as an electrode deposited onto solid electrolyte. The invention is also directed to the method of making same.

Novak, Robert F. (Farmington Hills, MI); Schmatz, Duane J. (Dearborn Heights, MI); Hunt, Thomas K. (Ann Arbor, MI)

1987-12-22

70

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

71

Electrical performance of skutterudites solar thermoelectric generators  

Microsoft Academic Search

The paper focuses on the electrical performance of skutterudites based solar thermoelectric generators (STG). Basics of STG mathematical modeling are reported. Two STG concepts, namely the flat plate model with identical collector and radiator areas and the STG configuration with concentrators have been considered. Their performance is assessed for different solar intensities. The idea is to understand how such systems

B. Lenoir; A. Dauscher; P. Poinas; H. Scherrer; L. Vikhor

2003-01-01

72

Experimental study on low-temperature waste heat thermoelectric generator  

Microsoft Academic Search

In order to further studies on thermoelectric generation, an experimental thermoelectric generator unit incorporating the commercially available thermoelectric modules with the parallel-plate heat exchanger has been constructed. The experiments are carried out to examine the influences of the main operating conditions, the hot and cold fluid inlet temperatures, flow rates and the load resistance, on the power output and conversion

Xing Niu; Jianlin Yu; Shuzhong Wang

2009-01-01

73

Heat Transfer Enhancement in Thermoelectric Power Generation  

Microsoft Academic Search

Heat transfer plays an important role in thermoelectric (TE) power generation because the higher the heat-transfer rate from the hot to the cold side of the TE material, the higher is the generation of electric power. However, high heat-transfer rate is difficult to achieve compactly when the hot and\\/or the cold sources are maintained by a flow of gas such

Shih-yung Hu

2009-01-01

74

Xenon filled silicon germanium thermoelectric generators  

NASA Technical Reports Server (NTRS)

An analysis is presented that shows the desirability and feasibility of using a xenon fill in the initial stages of operation of a silicon-germanium radioisotope thermoelectric generator to be used in outer-planetary exploration. The xenon cover gas offers protection against oxidation and against material sublimation, and allows the generator to deliver required power throughout the prelaunch and launch phases. The protective mechanisms afforded by the xenon cover gas and the mechanization of a xenon supply system are also discussed.

Dewinter, F.

1972-01-01

75

Solar Thermoelectric Generator for Micropower Applications  

NASA Astrophysics Data System (ADS)

Solar thermoelectric generators (STG) using cheap parabolic concentrators with high- ZT modules can be a cost-effective alternative to solar photovoltaics for micropower generation. A thermodynamic analysis is presented for predicting the thermal-to-electrical conversion efficiency for the generator. With solar concentration of 66× suns, a system efficiency of 3% was measured for a commercial Bi2Te3 module with output power of 1.8 W. Using novel thermoelectric materials such as n-type ErAs:(InGaAs)1- x (InAlAs) x and p-type (AgSbTe) x (PbSnTe)1- x , a conversion efficiency of 5.6% can be achieved for a STG at 120× suns.

Amatya, R.; Ram, R. J.

2010-09-01

76

Solar thermoelectric power generation for Mercury orbiter missions  

NASA Technical Reports Server (NTRS)

Mercury orbiter mission study results have shown that conventional silicon solar cell array technology is not adequate to produce power because of expected temperatures which range from -90 C to +285 C in about 50 minutes for 16 sun eclipses/day. The solar thermoelectric generator (STG), which requires relatively high temperatures, is being developed as a replacement power source. Several thermoelectric technologies (i.e., lead telluride alloys, bismuth telluride, selenide, and silicon-germanium alloys have been examined for their suitability. Solar concentrator configurations (i.e., flat plate, Fresnel lens, mini-cone, and Cassegrain types) were also studied as candidates for increasing incident radiation during Mercury orbital operations. Detailed results are presented, and show that an STG design based on the use of silicon-germanium alloy thermoelectric material and using high-voltage thermopiles with individual miniconical concentrators presents the optimum combination of technology and configuration for minimizing power source mass.

Swerdling, M.; Raag, V.

1979-01-01

77

Detailed Modeling and Irreversible Transfer Process Analysis of a Multi-Element Thermoelectric Generator System  

NASA Astrophysics Data System (ADS)

Thermoelectric (TE) power generation technology, due to its several advantages, is becoming a noteworthy research direction. Many researchers conduct their performance analysis and optimization of TE devices and related applications based on the generalized thermoelectric energy balance equations. These generalized TE equations involve the internal irreversibility of Joule heating inside the thermoelectric device and heat leakage through the thermoelectric couple leg. However, it is assumed that the thermoelectric generator (TEG) is thermally isolated from the surroundings except for the heat flows at the cold and hot junctions. Since the thermoelectric generator is a multi-element device in practice, being composed of many fundamental TE couple legs, the effect of heat transfer between the TE couple leg and the ambient environment is not negligible. In this paper, based on basic theories of thermoelectric power generation and thermal science, detailed modeling of a thermoelectric generator taking account of the phenomenon of energy loss from the TE couple leg is reported. The revised generalized thermoelectric energy balance equations considering the effect of heat transfer between the TE couple leg and the ambient environment have been derived. Furthermore, characteristics of a multi-element thermoelectric generator with irreversibility have been investigated on the basis of the new derived TE equations. In the present investigation, second-law-based thermodynamic analysis (exergy analysis) has been applied to the irreversible heat transfer process in particular. It is found that the existence of the irreversible heat convection process causes a large loss of heat exergy in the TEG system, and using thermoelectric generators for low-grade waste heat recovery has promising potential. The results of irreversibility analysis, especially irreversible effects on generator system performance, based on the system model established in detail have guiding significance for the development and application of thermoelectric generators, particularly for the design and optimization of TE modules.

Xiao, Heng; Gou, Xiaolong; Yang, Suwen

2011-05-01

78

New Physical Model for Thermoelectric Generators  

Microsoft Academic Search

In this paper we describe a new analytical physical model for thermoelectric generators (TEGs). The model includes the Thomson\\u000a effect, the Peltier heat, a parameterization of the Joule heat, as well as all thermal and electrical resistances. Geometry\\u000a optimization and investigations of the influence of Peltier heat and the heat source, as well as heat sink conditions and\\u000a the load

Michael Freunek; Monika Müller; Tolgay Ungan; William Walker; Leonhard M. Reindl

2009-01-01

79

Optimization of a combined thermionic–thermoelectric generator  

Microsoft Academic Search

A combined thermionic–thermoelectric generator is proposed in this paper. The thermoelectric generator makes use of the rejected heat from the anode of the thermionic generator, and produces additional electrical power. The combined generator system has both improved efficiency and power output. Optimization analysis of the combined generator is presented in this work.

X. C Xuan; D Li

2003-01-01

80

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

81

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

82

Towards a nanostructured thermoelectric generator using ion-track lithography  

Microsoft Academic Search

This paper presents the process development towards a new generation of nanostructured thermoelectric generators for power harvesting from small temperature gradients by using a combination of traditional silicon microfabrication techniques, electroplating and submicron ion-track nanolithography. Polyimide nanotemplates with pore diameters ranging from 30 nm to 120 nm were fabricated. Preliminary results from the fabrication of poly(methyl methacrylate) (PMMA)-nanostructured templates are

E. Koukharenko; X. Li; I. Nandhakumar; N. Frety; S. P. Beeby; D. Cox; M. J. Tudor; B. Schiedt; C. Trautmann; A. Bertsch; N. M. White

2008-01-01

83

Towards a nanostructured thermoelectric generator using ion-track lithography  

NASA Astrophysics Data System (ADS)

This paper presents the process development towards a new generation of nanostructured thermoelectric generators for power harvesting from small temperature gradients by using a combination of traditional silicon microfabrication techniques, electroplating and submicron ion-track nanolithography. Polyimide nanotemplates with pore diameters ranging from 30 nm to 120 nm were fabricated. Preliminary results from the fabrication of poly(methyl methacrylate) (PMMA)-nanostructured templates are reported. Bi2Te3 nanowires (80 and 120 nm diameters) were electroplated into polyimide ion-track nanotemplates. Bi2Te3 nanowires of a R3 m structure, with preferential orientation in (1 1 0) crystallographic plans, were electroplated. The chemical composition of Bi2Te3 with nearly stoichiometric composition (Bi2.31Te3) was obtained. Homogeneity profiles of the chemical composition were obtained. A fine-grained observed microstructure (6-10 nm) and (1 1 0) crystalline orientation were obtained, which is extremely promising for improving the thermoelectric material properties. The thermoelectric properties of the Bi2Te3-electroplated thin films (Seebeck coefficient ?) and electrical resistivity of the Bi2Te3 bundle nanowires were found to be -52 µV K-1 and ~14 M? cm, respectively. Polyimide (Kapton foil) and PMMA 950 photoresists were promising materials for the realization of a nanostructured thermoelectric generator on flexible and rigid substrates, respectively.

Koukharenko, E.; Li, X.; Nandhakumar, I.; Frety, N.; Beeby, S. P.; Cox, D.; Tudor, M. J.; Schiedt, B.; Trautmann, C.; Bertsch, A.; White, N. M.

2008-10-01

84

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

85

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

86

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

87

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

88

Compensation of voltage drops in solid-state switches used with thermoelectric generators  

NASA Technical Reports Server (NTRS)

Seebeck effect solid state switch was developed eliminating thermoelectric generator switch voltage drops. Semiconductor switches were fabricated from materials with large Seebeck coefficients, arranged such that Seebeck potential is generated with such polarity that current flow is aided.

Shimada, K.

1972-01-01

89

300 Watt Portable Thermoelectric Generator.  

National Technical Information Service (NTIS)

Two 5 couple modules were constructed and put on life test. A 9-couple module of the design which will be used in the generator was constructed and tested. Thermal experiments on cold-end heat transfer were completed and couple hardware design was finaliz...

R. D. Carlton

1965-01-01

90

Compatibility of segmented thermoelectric generators  

Microsoft Academic Search

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 were mainly concerned with materials that have the highest figure of merit in the temperature range. However, the example of SiGe segmented with Bi2Te3 and\\/or

T. S. Ursell; G. J. Snyder

2002-01-01

91

Case study on thermoelectric generation system utilizing the exhaust gas of interal-combustion power plant  

Microsoft Academic Search

This paper discusses the effects of element length, installation of fins and exhaust gas flow rate on the power output and the conversion efficiency of a thermoelectric generation system using the exhaust gas of an internal combustion plant. The thermoelectric module consists of bismuth-tellurium based thermoelectric elements, electrodes, insulators, etc. A thermoelectric generation system consists of thermoelectric generation modules sandwiched

T. Furue; T. Hayashida; Y. Imaizumi; T. Inoue; K. Nagao; A. Nagai; I. Fujii; T. Sakurai

1998-01-01

92

Cooling radioisotope thermoelectric generators in the Shuttle  

NASA Technical Reports Server (NTRS)

Radioisotope thermoelectric generators (RTG) to be used on future spacecraft and launched by the Shuttle must be cooled from the time they are installed and enclosed until the spacecraft is deployed from the Shuttle. A special Cooling Kit maintains their temperature well below critical by circulating water through the coils soldered to them and through a heat exchanger that boils water and externally discharges the resulting steam. The RTG Cooling Kit, including its support frame, if fully charged with about 64 kg of evaporation water, will increase the Shuttle launch mass by about 200 kg.

Norman, R. M.

1978-01-01

93

Thermoelectric Generators using Solar Thermal Energy in Heated Road Pavement  

Microsoft Academic Search

The temperature of road pavement rises up to 70degC in summer due to the effect of the solar radiation. The authors have developed a pavement-cooling system using thermoelectric generator. Heat in the pavement is collected as heated water in a heat collection tube installed in the pavement. River water near the road is used as a coolant. Electric power is

M. Hasebe; Y. Kamikawa; S. Meiarashi

2006-01-01

94

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

95

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

96

Optimization of Heat Sink–Limited Thermoelectric Generators  

Microsoft Academic Search

Many recent advances in thermoelectrics have focused on the nanoscale engineering of materials for higher figure of merit (Z). A thermoelectric generator using these thin-film materials can present new challenges due to its inherently large temperature gradient, but also correspondingly larger generated power if the heat can be managed. In such cases performance is expected to be limited as much

P. M. Mayer; R. J. Ram

2006-01-01

97

Thermoelectric materials development. Final report.  

National Technical Information Service (NTIS)

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 coefficien...

J. P. Fleurial T. Caillat A. Borshchevsky

1998-01-01

98

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

99

End-on radioisotope thermoelectric generator impact tests  

SciTech Connect

The General-Purpose Heat Source (GPHS) 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). The modular GPHS design was developed to address both survivability during launch abort and return from orbit. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure.

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

1997-01-01

100

Optimal design of small ?T thermoelectric generation systems  

Microsoft Academic Search

Thermoelectric generation systems for utilizing waste heat and ambient temperature swings have been proposed that would involve temperature differences on the order of 1–10 K. The inherently low thermodynamic efficiency of such systems requires that a relatively large amount of heat pass through the system for a given rate of electricity production. The coupled design of the thermoelectric module and

James W. Stevens

2001-01-01

101

Thermoelectric materials development. Final report  

Microsoft Academic Search

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

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

1998-01-01

102

Thermoelectric Power Generation System Using Waste Heat from Biomass Drying  

NASA Astrophysics Data System (ADS)

This paper looks at thermoelectric power generation from waste heat from a biomass drier. In this study, the researchers selected four thermoelectric modules: two thermoelectric cooling modules (Model A: MT2-1,6-127 and Model B: TEC1-12708) and two thermoelectric power generation modules (Model C: TEP1-1264-3.4 and Model D: TEG1-1260-5.1) for testing at temperatures between 25°C and 230°C. Test results indicated that the thermoelectric TEC1-12708 could generate a maximum power output of 1 W/module and TEP1-1264-3.4, TEG1-1260-5.1, and MT2-1,6-127 could generate 1.07 W/module, 0.88 W/module, and 0.76 W/module, respectively. Therefore, the thermoelectric cooling of TEC1-12708 was appropriate to use for thermoelectric power generation from waste heat. The experiments used four ventilation fans (6 W, 2.50 m3/s) and 12 thermoelectric modules which were installed in the back of a charcoal brazier. The experiments were conducted and tested in conditions of recycling 100%, 75%, 50%, and 25% of outlet air. Testing results identified that the temperatures of the drying room were 81°C, 76°C, 70°C, and 64°C, respectively. The power generation system could generate about 22.4 W (14 V, 1.6 A) with an air flow of 9.62 m3/s. The thermoelectric module can convert 4.08% of the heat energy to electrical energy.

Maneewan, S.; Chindaruksa, S.

2009-07-01

103

A new type of low power thermoelectric micro-generator fabricated by nanowire array thermoelectric material  

Microsoft Academic Search

A new type of thermoelectric micro-generator, which is composed of n-type and p-type Bi2Te3 nanowire array thermoelectric materials, is designed to be energy source for miniaturized solid-state devices such as MEMS, micro-electrical system and even “system on a chip”. The nanowire arrays are fabricated by electrochemical deposition of Bi2Te3 into the nano-pores of alumina template. The measurements showed that the

Wei Wang; Falong Jia; Qinghua Huang; Jianzhong Zhang

2005-01-01

104

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

105

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

106

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

107

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

NASA Technical Reports Server (NTRS)

Thermoelectric (TE) power generation is an increasingly important power generation technology. Major advantages include: no moving parts, low-weight, modularity, covertness/silence, high power density, low amortized cost, and long service life with minimum or no required maintenance. Despite low efficiency of power generation, there are many specialized needs for electrical power that TE technologies can uniquely and successfully address. Recent advances in thermoelectric materials technology have rekindled acute interest in thermoelectric power generation. We have developed single crystalline n- and p- type PbTe crystals and are also, developing PbTe bulk nanocomposites using PbTe nano powders and emerging filed assisted sintering technology (FAST). We will discuss the materials requirements for efficient thermoelectric power generation using waste heat at intermediate temperature range (6500 to 8500 K). We will present our recent results on production of n- and p- type PbTe crystals and their thermoelectric characterization. Relative characteristics and performance of PbTe bulk single crystals and nano composites for thermoelectric power generation will be discussed.

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

2012-01-01

108

Segmented Thermoelectric Multicouple Converter Technology Development  

NASA Astrophysics Data System (ADS)

The primary objectives of the segmented thermoelectric multicouple converter (STMC) technology development effort are: to define a conceptual design for a passive, low mass (3000 kg), long life (15 years) thermoelectric advanced Space Reactor Power System that provides 100kWe 400 Volt dc power for a 6000 volt dc electric propulsion system, to prepare a preliminary design of the power conversion system and to prepare technology development plan to advance power conversion system technology to TRL 6. The SRPS consists of a heat pipe cooled reactor radiatively couple to high efficiency solid-state segmented thermoelectric multicouple converters which are conductively coupled to a low mass heat pipe radiator. The SRPS conceptual design as well as the Power Conversion System preliminary design is complete and their description reported in this paper.

Mondt, Jack; Johnson, Ken; Fleurial, Jean-Pierre; El Genk, Mohamed; Frye, Patrick; Determan, Bill

2005-02-01

109

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

110

INVESTIGATION OF GAS PRESSURE BUILDUP IN THERMOELECTRIC SNAP GENERATORS  

Microsoft Academic Search

The program for investigating gas pressure buildup in thermoelectric ;\\u000a generators was initiated in February 1963 and continued through December 1963. ;\\u000a The program objectives were to determine the source(s) of internal gas pressure ;\\u000a increase in SNAP thermoelectric generators, establish methods of alleviating or ;\\u000a eliminating the condition, and conduct a proof-of-principle test on an ;\\u000a electrically heated 60-watt

W. A. McDonald; J. McGrew

1964-01-01

111

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

112

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

113

Development and applications of solar-based thermoelectric technologies  

Microsoft Academic Search

In this paper a survey of solar-based driven thermoelectric technologies and their applications is presented. Initially, a brief analysis of the environmental problems related to the use of conventional technologies and energy sources is presented and the benefits offered by thermoelectric technologies and renewable energy systems are outlined. The development history of solar-based thermoelectric technologies is introduced together with the

Hongxia Xi; Lingai Luo; Gilles Fraisse

2007-01-01

114

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

115

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 Bi2Te3 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

2006-04-01

116

Performance of cryogenic thermoelectric generators in LNG cold energy utilization  

Microsoft Academic Search

The cold energy of liquefied natural gas (LNG) is generally wasted when the LNG is extracted for utilization. This paper proposes cryogenic thermoelectric generators to recover this cold energy. The theoretical performance of the generator has been analyzed. An analytical method and numerical method of calculation of the optimum parameters of the generator have been demonstrated.

Wei Sun; Peng Hu; Zeshao Chen; Lei Jia

2005-01-01

117

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

118

Integrating Phase-Change Materials into Automotive Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

Because the heat emitted by conventional combustion-engine vehicles during operation has highly transient properties, automotive thermoelectric generators (TEG) are intended for a particular operating state (design point). This, however, leads to two problems. First, whenever the combustion engine runs at low load, the maximum operating temperature cannot be properly utilised; second, a combustion engine at high load requires partial diversion of exhaust gas away from the TEG to protect the thermoelectric modules. An attractive means of stabilising dynamic exhaust behaviour (thereby keeping the TEG operating status at the design point for as long as possible) is use of latent heat storage, also known as phase-change materials (PCM). By positioning PCM between module and exhaust heat conduit, and choosing a material with a phase-change temperature matching the module's optimum operating temperature, it can be used as heat storage. This paper presents results obtained during examination of the effect of integration of latent heat storage on the potential of automotive TEG to convert exhaust heat. The research resulted in the development of a concept based on the initial integration idea, followed by proof of concept by use of a specially created prototype. In addition, the potential amount of energy obtained by use of a PCM-equipped TEG was calculated. The simulations indicated a significant increase in electrical energy was obtained in the selected test cycle.

Klein Altstedde, Mirko; Rinderknecht, Frank; Friedrich, Horst

2014-06-01

119

Effect of heat transfer on the performance of thermoelectric generators  

Microsoft Academic Search

The power output and efficiency expressions for thermoelectric (semiconductor) generators which is composed of multi-elements are derived with considerations of heat transfer irreversibility in the heat exchangers between the generator and the heat reservoirs. Numerical examples are provided. The effects of heat transfer and the number of elements on the performance are analyzed.

Lingen Chen; Jianzheng Gong; Fengrui Sun; Chih Wu

2002-01-01

120

A Novel Photo-Thermoelectric Generator Integrating Dye-sensitized Solar Cells with Thermoelectric Modules  

NASA Astrophysics Data System (ADS)

In this study, we adopt two different morphologies of self-made nano-TiO2 powder to prepare a double-layer photoelectrode for dye-sensitized solar cells (DSSCs). Further, DSSC module and thermoelectric generator (TEG) coated with nano-Cu thin film were integrated with a novel photo-thermoelectric generator. For the fabrication of photoelectric conversion modules, TiO2 nanoparticles (H200) fabricated by the hydrothermal method and the powder of TiO2 nanofluid prepared by the submerged arc nanofluid synthesis system (SANSS) were utilized to prepare a double-layer thin film using a surgical blade as the photoelectrode of DSSCs. And then, commercial nano-Cu powder was coated on two sides of TEG to fabricate thermoelectric conversion module by surgical blade. Nano-Cu thin film, as the medium of thermal conductivity, can effectively transfer heat produced by sunlight on the surface of DSSC to the two sides of TEG. Finally, the two modules were combined into the optical thermoelectric generator. The overall experiment utilizes the intensity of 100 mW/cm2 illumination of simulated sunlight, which can produce 4.97 mW/cm2, an increase of 2.87% output compared with merely employing the DSSCs.

Ho Chang,; Mu-Jung Kao,; Kouhsiu David Huang,; Sih-Li Chen,; Zhi-Rong Yu,

2010-06-01

121

Prospects for SiGe thermoelectric generators  

NASA Astrophysics Data System (ADS)

Thermoelectric materials are one potential technology that could be used for energy harvesting. Here we report results from nanoscale Ge/SiGe heterostructure materials grown on Si substrates designed to enhance the thermoelectric performance over bulk materials at room temperature. The materials and devices are aimed at integrated energy harvesters for autonomous sensing applications. We report Seebeck coefficients up to 279.5 ± 1.2 ?V/K at room temperature with electrical conductivities of 77,200 S/m which produce a high power factor of 6.02 ± 0.05 mW m-1 K-2 and a ZT of 0.135 ± 0.074 at room temperature. Methods for microfabricating modules will be described along with the first demonstration of power output from flip-chip bonded SiGe legs.

Samarelli, A.; Ferre Llin, L.; Cecchi, S.; Frigerio, J.; Chrastina, D.; Isella, G.; Müller Gubler, E.; Etzelstorfer, T.; Stangl, J.; Zhang, Y.; Weaver, J. M. R.; Dobson, P. S.; Paul, D. J.

2014-08-01

122

Enhancement in Performance of the Tubular Thermoelectric Generator (TTEG)  

NASA Astrophysics Data System (ADS)

For use in a tubular thermoelectric generator (TTEG), we fabricated tubular Bi0.5Sb1.5Te3/Ni composite using a melt-spinning technique combined with the spark plasma sintering (SPS) process. With this method, powder sintering, joining of two different materials, and tubular shaping can be achieved simultaneously. The tilted laminate structure which is crucial for the transverse thermoelectric effect was successfully achieved in the sample after SPS densification. The sintered samples showed better mechanical stability and thermoelectric properties compared with the previously studied melt-cast sample. We confirmed larger open-circuit voltage of 240 mV and generating power of 2.5 W with a 100-mm-long TTEG under the small temperature difference of 83 K, and the corresponding power density for a unit heat transfer surface area was approximately 800 W m-2.

Sakai, Akihiro; Kanno, Tsutomu; Takahashi, Kouhei; Tamaki, Hiromasa; Adachi, Hideaki; Yamada, Yuka

2013-07-01

123

Modeling a Thermoelectric Generator Applied to Diesel Automotive Heat Recovery  

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

124

A numerical model for thermoelectric generator with the parallel-plate heat exchanger  

Microsoft Academic Search

This paper presents a numerical model to predict the performance of thermoelectric generator with the parallel-plate heat exchanger. The model is based on an elemental approach and exhibits its feature in analyzing the temperature change in a thermoelectric generator and concomitantly its performance under operation conditions. The numerical simulated examples are demonstrated for the thermoelectric generator of parallel flow type

Jianlin Yu; Hua Zhao

2007-01-01

125

A microprocessor-based controller for a thermoelectric generator  

NASA Astrophysics Data System (ADS)

The design of the microprocessor-based electronic controller that is being developed for the 100-W portable G-78/G thermoelectric generator (TEG) is described. The central processing unit of the controller is capable of exercising control over most of the TEG's hardware functions, as well as receiving performance data for evaluating and adjusting the TEG operation. During all operating phases of the software (the turn-on, the ignition and warm-up sequences, the power-keeping and load-management phases, and the turn-off) the controller is constantly monitoring the status of the TEG. The controller performance can be altered by editing the program, rather than changing hardware design.

Glenn, G. Douglas

126

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

127

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. Franosh; G. Wachutka

2003-01-01

128

Calculation of thermoelectric power generation performance using finite element analysis  

Microsoft Academic Search

Recent papers have covered the merits of using finite elements to calculate the thermoelectric device performance for steady-state conditions. Likewise, papers have covered the use of finite elements to model transient cooling conditions. It remains then to model power generation performance with finite elements and compare that model with various other modeling techniques. This Analysis was based on a single

Paul G. Lau; Richard J. Buist

1997-01-01

129

Power performance of US space radioisotope thermoelectric generators  

Microsoft Academic Search

Since 1961, the United States has flown 41 radioisotope thermoelectric generators (RTGs) and one reactor to provide power for 25 space power systems. Thirty-eight of these nuclear power sources on 22 space systems are still in space or on other planetary bodies. This paper summarizes the design and power performance of each of the basic RTG types that have been

Gary L. Bennett; E. A. Skrabek

1996-01-01

130

Thermoelectric generator utilizing boiling-condensation (experiment and modeling)  

Microsoft Academic Search

A thermoelectric generator utilizing boiling and condensation of thermal medium circulating between a boiler and condensers was proposed in this study. Fuluorinert (FC5312) was used as the thermal medium (working fluid). A vertical tube type boiler with an outside forced convective heat transfer and an inside natural convective boiling was chosen. In order to increase the hot side temperature of

Ren Cai Chu; Kanichi KADOTANI; Toshiya SHINTANI; Toshinobu TANIMURA; Tsutomu HATANAKA; S. Nishio

2003-01-01

131

Thermoelectric-generator with linear phenomenological heat-transfer law  

Microsoft Academic Search

The performance of multi-element thermoelectric-generators, assuming heat-transfer irreversibilities which obey the linear phenomenological heat-transfer law Q?(?T?1), is studied in this paper by combining finite-time thermodynamics with non-equilibrium thermodynamics. The performance characteristics of the output power, efficiency and working electrical-current are described by numerical examples.

Lingen Chen; Fengrui Sun; Chih Wu

2005-01-01

132

Experimental demonstration of thermal management using thermoelectric generation  

Microsoft Academic Search

It has been well established that thermal management of electronic equipment is a critical need for the continued success of the microelectronics industry. Portable electronic devices, such as notebook computers and cellular telephones, require that the thermal solution be small, light, and energy efficient. Small-scale thermoelectric (TE) modules can be used to generate electricity from the waste heat of the

Gary L. Solbrekken; Kazuaki Yazawa; Avram Bar-Cohen

2004-01-01

133

Achieving Maximum Power in Thermoelectric Generation with Simple Power Electronics  

NASA Astrophysics Data System (ADS)

A thermoelectric generator typically delivers a relatively low power output, and hence it is of great practical importance to determine a design and operating condition close to those which can provide the maximum attainable power. To maintain a favorable condition for the maximum power output, power electronics circuits are usually applied. One of the simplest methods is to control the operating voltage at half the open-circuit voltage, assuming that the typical impedance-matching condition, in which the load and internal resistances are matched, yields the maximum power output. However, recent investigations have shown that, when external thermal resistances exist between the thermoelectric modules and thermal reservoirs, the impedance-matching condition is not identical to the condition for the maximum power output. In this article, it is argued that, although the impedance-matching condition is not the condition for maximum power output, the maximum power is still achievable when the operating voltage is kept at half the open-circuit voltage. More precisely, it is shown that the typical V- I curve for thermoelectric generators must show approximately linear behavior, which justifies the use of a simple strategy in thermoelectric power generation applications. The conditions for the validity of the approximation are mathematically discussed, supported by a few examples. Experimental evidence at room temperature is also provided.

Youn, Nari; Lee, Hohyun; Wee, Daehyun; Gomez, Miguel; Reid, Rachel; Ohara, Brandon

2014-06-01

134

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

135

Program of Thermoelectric Generator Testing and Rtg Degradation Mechanisms Evaluation. Progress Report No. 14.  

National Technical Information Service (NTIS)

Progress during September and October 1975 in the development and evaluation of thermoelectric generators for use with radioisotope heat sources is reported. Information is included on the operation of Si sub 3 N sub 4 -coated SiGe legs in vacuum and in C...

1975-01-01

136

Thermoelectric power generation: Converting low-grade heat into electricity  

Microsoft Academic Search

This article describes some of the fundamental aspects of thermoelectric power generation, which employs low-temperature heat\\u000a sources to create electricity. The focus is on a potential system design and viable thermocouple materials. Regarding generator\\u000a design, a system is proposed that uses forcedair circulation and a multistage heat-exchanger to efficiently convert the heat\\u000a content of a low-grade heat source into useful

K. Ono; R. O. Suzuki

1998-01-01

137

Wearable Thermoelectric Generators for Body-Powered Devices  

Microsoft Academic Search

This paper presents a discussion on energy scavenging for wearable devices in conjunction with human body properties. Motivation,\\u000a analysis of the relevant properties of the human body, and results of optimization of a thermopile and a thermoelectric generator\\u000a for wearable and portable devices are presented. The theoretical limit for power generation on human beings is evaluated and\\u000a confirmed by experimental

V. Leonov; R. J. M. Vullers

2009-01-01

138

Thermoelectric Generators Pp-6074()/U and Pp-6075()/U.  

National Technical Information Service (NTIS)

The report describes engineering development studies on 10 Ampere, PP-6074( )/U, and 20 Ampere, PP-6075( )/U, 28 volt d.c. power sources of the thermoelectric type to ascertain the validity of the mechanical design and to determine physical and electrical...

G. E. Guazzoni R. T. Nichols

1968-01-01

139

Design concepts of solar thermoelectric generators in space applications  

NASA Technical Reports Server (NTRS)

Several thermoelectric technologies have been examined as to their suitability for use in a solar thermoelectric generator (STG) as a nonpropulsive power source for space applications. The results show that of all the presently available thermoelectric technologies, i.e., lead telluride, bismuth telluride, selenide, and silicon-germanium alloys, the latter type provides the optimum STG. Detailed results are presented on the performance and configurational characteristics of various silicon-germanium alloy STGs, including the performance of such STGs as a function of time in a Mercury orbit and the orbit of Mercury around the sun. It is shown that an STG design based on the use of silicon germanium alloy thermoelectric material, using multiple high voltage thermopiles with individual solar concentrators, presents the optimum combination of technology and configuration for minimizing power source mass. Additional concepts studied and discussed are the flat plate individual thermopile type and single concentrator compact thermopile type. The STG possesses an attractive potential for this application and represents a useful addition to the family of power sources for consideration in various space applications.

Raag, V.; Hankins, L.; Swerdling, M.

1978-01-01

140

Analytical predictions of RTG power degradation. [Radioisotope Thermoelectric Generator  

NASA Technical Reports Server (NTRS)

The DEGRA computer code that is based on a mathematical model which predicts performance and time-temperature dependent degradation of a radioisotope thermoelectric generator is discussed. The computer code has been used to predict performance and generator degradation for the selenide Ground Demonstration Unit (GDS-1) and the generator used in the Galileo Project. Results of parametric studies of load voltage vs generator output are examined as well as the I-V curve and the resulting predicted power vs voltage. The paper also discusses the increased capability features contained in DEGRA2 and future plans for expanding the computer code performance.

Noon, E. L.; Raag, V.

1979-01-01

141

Potential applications of advanced thermoelectrics in the automobile industry  

Microsoft Academic Search

Several proposed applications of thermoelectric devices in the automobile industry are reviewed. These are: exhaust gas thermoelectric generator; air conditioning (thermoelectric cooling); and microelectronics cooling using thin-film thermoelectrics. The key to the realization of these technologies is the continued development of new materials with increased thermoelectric efficiency

D. T. Morelli

1996-01-01

142

Computer program for the transient analysis of radioisotope thermoelectric generators.  

NASA Technical Reports Server (NTRS)

A computer program is described which represents a comprehensive analytical tool providing the capability for predicting the output power and temperature profile of an arbitrary radioisotope thermoelectric generator (RTG) design in the presence of time-dependent operating conditions. The approach taken involves the merging of three existing computer programs - namely, an RTG weight optimization design program, a thermoelectric analysis program, and a nodal heat-transfer computer program. A total of seven transient conditions are included in the computer program as the principal transients affecting long- and short-term performance characteristics of RTGs. This computer program is unique in that it designs an optimum RTG, generates a thermal model or analog and performs heat-transfer analysis of the RTG under user-specified transient conditions.

Eggers, P. E.; Ridihalgh, J. L.

1972-01-01

143

High-energy density miniature thermoelectric generator using catalytic combustion  

Microsoft Academic Search

This paper describes the components and system of a thermoelectric (TE) generator with a catalytic butane combustor. The combustion chamber with a size of 8 mm×8 mm×0.4 mm is etched in a 0.65-mm-thick silicon substrate, and bonded to both sides of a 0.77-mm-thick glass substrate with a thin-film ignition heater. A set of 34 couples of BiTe TE elements, each

Kazushi Yoshida; Shuji Tanaka; Shigeaki Tomonari; Daisuke Satoh; Masayoshi Esashi

2006-01-01

144

Integration of dye-sensitized solar cells, thermoelectric modules and electrical storage loop system to constitute a novel photothermoelectric generator.  

PubMed

This study self-develops a novel type of photothermoelectric power generation modules. Dye-sensitized solar cells (DSSCs) serve as the photoelectric conversion system and a copper (Cu) heat-transfer nanofilm coating on both sides of the thermoelectric generator (TEG) acts as a thermoelectric conversion system. Thus module assembly absorbs light and generates electricity by DSSCs, and also recycles waste heat and generates power by the TEG. In addition, a set of pulsating heat pipes (PHP) filled with Cu nanofluid is placed on the cooling side to increase cooling effects and enhance the power generation efficiency. Results show that when the heat source of thermoelectric modules reaches 90 degrees C, TEG power output is increased by 85.7%. Besides, after thermoelectric modules are heated by additional heat source at 80 degrees C, the electrical energy generated by them can let a NiMH cell (1.25 V) be sufficiently charged in about 30 minutes. When photothermoelectric modules is illumined by simulated light, the temperature difference of two sides of TEG can reach 7 degrees C and the thermoelectric conversion efficiency is 2.17%. Furthermore, the power output of the thermoelectric modules is 11.48 mW/cm2, enhancing 1.4 % compared to merely using DSSCs module. PMID:22962827

Chang, Ho; Yu, Zhi-Rong

2012-08-01

145

Performance of the 1 kW thermoelectric generator for diesel engines  

SciTech Connect

Hi-Z Technology, Inc. (Hi-Z) has been developing a 1 kW thermoelectric generator for class eight Diesel truck engines under U.S. Department of Energy and California Energy Commission funding since 1992. The purpose of this generator is to replace the currently used shaft-driven alternator by converting part of the waste heat in the engine`s exhaust directly to electricity. The preliminary design of this generator was reported at the 1992 meeting of the XI-ICT in Arlington, Texas. This paper will report on the final mechanical, thermal and thermoelectric design of this generator. The generator uses seventy-two of Hi-Z`s 13 Watt bismuth-telluride thermoelectric modules for energy conversion. The number of modules and their arrangement has remained constant through the program. The 1 kW generator was tested on several engines during the development process. Many of the design features were changed during this development as more information was obtained. We have only recently reached our design goal of 1 kW output. The output parameters of the generator are reported. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Bass, J.C.; Elsner, N.B.; Leavitt, F.A. [Hi-Z Technology, Inc (??)

1994-08-10

146

Real-time monitoring during transportation of a radioisotope thermoelectric generator (RTG) using the radioisotope thermoelectric generator transportation system (RTGTS)  

SciTech Connect

The Radioisotopic Thermoelectric Generators (RTGs) that will be used to support the Cassini mission will be transported in the Radioisotope Thermoelectric Generator Transportation System (RTGTS). To ensure that the RTGs will not be affected during transportation, all parameters that could adversely affect RTG's performance must be monitored. The Instrumentation and Data Acquisition System (IDAS) for the RTGTS displays, monitors, and records all critical packaging and trailer system parameters. The IDAS also monitors the package temperature control system, RTG package shock and vibration data, and diesel fuel levels for the diesel fuel tanks. The IDAS alarms if any of these parameters reach an out-of-limit condition. This paper discusses the real-time monitoring during transportation of the Cassini RTGs using the RTGTS IDAS.

Pugh, Barry K. [EG and G Mound Applied Technologies P.O. Box 3000 Miamisburg, Ohio 45343-3000 (United States)

1997-01-10

147

Real-time monitoring during transportation of a radioisotope thermoelectric generator (RTG) using the radioisotope thermoelectric generator transportation system (RTGTS)  

SciTech Connect

The Radioisotopic Thermoelectric Generators (RTGs) that will be used to support the Cassini mission will be transported in the Radioisotope Thermoelectric Generator Transportation System (RTGTS). To ensure that the RTGs will not be affected during transportation, all parameters that could adversely affect RTG{close_quote}s performance must be monitored. The Instrumentation and Data Acquisition System (IDAS) for the RTGTS displays, monitors, and records all critical packaging and trailer system parameters. The IDAS also monitors the package temperature control system, RTG package shock and vibration data, and diesel fuel levels for the diesel fuel tanks. The IDAS alarms if any of these parameters reach an out-of-limit condition. This paper discusses the real-time monitoring during transportation of the Cassini RTGs using the RTGTS IDAS. {copyright} {ital 1997 American Institute of Physics.}

Pugh, B.K. [EGG Mound Applied Technologies P.O. Box 3000 Miamisburg, Ohio45343-3000 (United States)

1997-01-01

148

Performance of the 1 kW thermoelectric generator for diesel engines  

Microsoft Academic Search

Hi-Z Technology, Inc. (Hi-Z) has been developing a 1 kW thermoelectric generator for class eight Diesel truck engines under U.S. Department of Energy and California Energy Commission funding since 1992. The purpose of this generator is to replace the currently used shaft-driven alternator by converting part of the waste heat in the engine’s exhaust directly to electricity. The preliminary design

J. C. Bass; N. B. Elsner; F. A. Leavitt

1994-01-01

149

Synthesis and pressure tuning of thermoelectric materials  

Microsoft Academic Search

Imagine a device with no moving parts that could be used for efficient refrigeration or electric power generation. Thermoelectric devices with these characteristics could be realized if materials with improved thermoelectric efficiencies, quantified by the thermoelectric figure of merit, ZT, were developed. There are currently many niche applications for thermoelectrics; however, no materials are yet known to exhibit values of

Deborah A. Polvani

2000-01-01

150

Radioisotope thermoelectric generator/thin fragment impact test  

SciTech Connect

The General-Purpose Heat Source (GPHS) 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 (PMS). The results of this test indicated that impact of the RTG by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the convertor housing, failure of one fueled clad, and release of a small quantity of fuel.

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

1998-12-31

151

Acoustic Optimization of Automotive Exhaust Heat Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

The potential for thermoelectric exhaust heat recovery in vehicles has been increasing with recent advances in the efficiency of thermoelectric generators (TEGs). This study analyzes the acoustic attenuation performance of exhaust-based TEGs. The acoustic characteristics of two different thermal designs of exhaust gas heat exchanger in TEGs are discussed in terms of transmission loss and acoustic insertion loss. GT-Power simulations and bench tests on a dynamometer with a high-performance production engine are carried out. Results indicate that the acoustic attenuation of TEGs could be determined and optimized. In addition, the feasibility of integration of exhaust-based TEGs and engine mufflers into the exhaust line is tested, which can help to reduce space and improve vehicle integration.

Su, C. Q.; Ye, B. Q.; Guo, X.; Hui, P.

2012-06-01

152

Thin Thermoelectric Generator System for Body Energy Harvesting  

NASA Astrophysics Data System (ADS)

Wearable thermoelectric generators (TEGs) harvest thermal energy generated by the body to generate useful electricity. The performance of these systems is limited by (1) the small working temperature differential between the body and ambient, (2) the desire to use natural air convection cooling on the cold side of the generator, and (3) the requirement for thin, lightweight systems that are comfortable for long-term use. Our work has focused on the design of the heat transfer system as part of the overall thermoelectric (TE) system. In particular, the small heat transfer coefficient for natural air convection results in a module thermal impedance that is smaller than that of the heat sink. In this heat-sink-limited regime, the thermal resistance of the generator should be optimized to match that of the heat sink to achieve the best performance. In addition, we have designed flat (1 mm thickness) copper heat spreaders to realize performance surpassing splayed pin heat sinks. Two-dimensional (2-D) heat spreading exploits the large surface area available in a wristband and allows patterned copper to efficiently cool the TE. A direct current (DC)/DC converter is integrated on the wristband. The system generates up to 28.5 ?W/cm2 before the converter and 8.6 ?W/cm2 after the converter, with 30% efficiency. It generates output of 4.15 V with overall thickness under 5 mm.

Settaluri, Krishna T.; Lo, Hsinyi; Ram, Rajeev J.

2012-06-01

153

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

2013-12-01

154

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

155

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

156

A study of commercial thermoelectric generation in a processing plant of combustible solid waste  

Microsoft Academic Search

This paper presents the applicability of a commercially available thermoelectric generator for waste heat recovery in a processing plant of combustible solid waste. Oil heat transfer medium is utilized for heating the commercially available thermoelectric generator employed in this study so that the generator can be operated at a much lower pressure than that using water. Low pressure operation is

A. Tsuyoshi; S. Kagawa; M. Sakamoto; K. Matsuura

1997-01-01

157

System and method to improve the power output and longevity 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. 1 figures.

Mowery, A.L. Jr.

1993-09-21

158

A General Model for the Electric Power and Energy Efficiency of a Solar Thermoelectric Generator  

Microsoft Academic Search

A general model for the electric power and energy efficiency of a solar thermoelectric generator is discussed, considering\\u000a the influences of the input energy, the thermal conductivity, the absorptivity and emissivity of the heat collector, and the\\u000a cooling water. The influences of these factors on the performance of the thermoelectric device are discussed, considering\\u000a the thermoelectric generator as a whole,

Yonghua Cai; Jinsheng Xiao; Wenyu Zhao; Xinfeng Tang; Qingjie Zhang

2011-01-01

159

Preliminary design of a miniature thermoelectric generator  

NASA Astrophysics Data System (ADS)

The U.S. Marine Corps has need for power sources in the 500 Watt area. These sources should be highly reliable, small, lightweight, signal suppressed, and be able to use liquid fuels, preferably Diesel, as the energy source. The desire to burn Diesel stems from the Armed Services desire to use Diesel as their main fuel source. Other fuels such as gasoline create a logistic problem and therefore, is to be avoided if at all possible. There are currently no known power supplies of this type commercially available on the open market. The Diesel motor generator sets that are available have higher power outputs and typically have a rather low mean-time before failure (MTBF). Earlier contact with Army personnel indicate that the MTBF of small portable Diesel motor/generator sets were about 175 hours. Similar experience has been reported by the U.S. Coast Guard in both their Major Aids to Navigation, Major ATON, and their Weather Data Buoys.

Bass, John C.

1994-04-01

160

A General Model for the Electric Power and Energy Efficiency of a Solar Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

A general model for the electric power and energy efficiency of a solar thermoelectric generator is discussed, considering the influences of the input energy, the thermal conductivity, the absorptivity and emissivity of the heat collector, and the cooling water. The influences of these factors on the performance of the thermoelectric device are discussed, considering the thermoelectric generator as a whole, including the heat collector, the thermoelectric device, and the cooling. Results show that high input energy, and high absorptivity and low emissivity of the heat collector, are helpful for obtaining a high-performance thermoelectric generator. A high thermal transfer coefficient of the cooling water can increase the temperature difference across the thermoelectric device but results in greater accessory power requirements if increased further.

Cai, Yonghua; Xiao, Jinsheng; Zhao, Wenyu; Tang, Xinfeng; Zhang, Qingjie

2011-05-01

161

Power Delivery from an Actual Thermoelectric Generation System  

NASA Astrophysics Data System (ADS)

Similar to photovoltaic (PV) and fuel cells, thermoelectric generators (TEGs) supply direct-current (DC) power, essentially requiring DC/alternating current (AC) conversion for delivery as electricity into the grid network. Use of PVs is already well established through power conditioning systems (PCSs) that enable DC/AC conversion with maximum-power-point tracking, which enables commercial use by customers. From the economic, legal, and regulatory perspectives, a commercial PCS for PVs should also be available for TEGs, preferably as is or with just simple adjustment. Herein, we report use of a PV PCS with an actual TEG. The results are analyzed, and proper application for TEGs is proposed.

Kaibe, Hiromasa; Kajihara, Takeshi; Nagano, Kouji; Makino, Kazuya; Hachiuma, Hirokuni; Natsuume, Daisuke

2014-06-01

162

Proposed strontium radiosotope thermoelectric generator fuel encapsulation facility  

NASA Astrophysics Data System (ADS)

The proposed Fuel Encapsulation Facility is a fully equipped facility for processing and encapsulating strontium Radioisotope Thermoelectric Generator (RTG) fuel from presently available Waste Encapsulation and Storage Facility (WESF) capsules. The facility location is on the second building level below ground of the Fuels and Materials Examination Facility (FMEF), Cells 142, 143, and 145. Capsules containing strontium fluoride (SrF2) would be received from the WESF in Cell 145 and transferred to the three adjacent cells for processing and encapsulation into the final RTG fuel configuration.

Adkins, Harold E.

1993-01-01

163

Proposed strontium radiosotope thermoelectric generator fuel encapsulation facility  

SciTech Connect

The proposed Fuel Encapsulation Facility is a fully equipped facility for processing and encapsulating strontium Radioisotope Thermoelectric Generator (RTG) fuel from presently available Waste Encapsulation and Storage Facility (WESF) capsules. The facility location is on the second building level below ground of the Fuels and Materials Examination Facility (FMEF), Cells 142, 143, and 145. Capsules containing strontium fluoride (SrF[sub 2]) would be received from the WESF in Cell 145 and transferred to the three adjacent cells for processing and encapsulation into the final RTG fuel configuration.

Adkins, H.E. (Westinghouse Hanford Company, P.O. Box 1970, Mail Stop N1-42, Richland, Washington 99352 (United States))

1993-01-10

164

Design of a low-input-voltage converter for thermoelectric generator  

Microsoft Academic Search

Low-grade exhaust heat is used to provide a reliable and independent power source for instrumentation circuitry by means of a thermoelectric generator (TEG). A design of a self-starting DC-DC power converter is developed and optimized for very-low-input voltages (below 300 mV) in order to allow operation at temperature differences of 20°C and less. A prototype is built, and the results

John M. Damaschke

1997-01-01

165

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

Microsoft Academic Search

The U.S. military uses large amounts of fuel during deployments and battlefield operations. This project sought to develop a lightweight, small form-factor, soldier-portable advanced thermoelectric (TE) system prototype to recover and convert waste heat from various deployed military equipment (i.e., diesel generators\\/engines, incinerators, vehicles, and potentially mobile kitchens), with the ultimate purpose of producing power for soldier battery charging, advanced

Terry J. Hendricks; Tim Hogan; Eldon D. Case; Charles J. Cauchy

2010-01-01

166

Powering wireless sensors: Microtechnology-based large-area thermoelectric generator for mass applications  

Microsoft Academic Search

In a thermoelectric generator (TEG), hundreds of individual couples of two thermoelectrically dissimilar materials are electrically connected in series, but thermally in parallel within a given heat flux. Thus, the devices generate a few 10s of mW and may, for example, be used in wireless sensor applications. Apart from highly integrated costly batch fabricated micro TEGs for niche applications, commercially

G. Pasold; P. Etlin; M. Hahn; U. Muster; V. Nersessian; D. Bonfrate; R. Buser; M. Cucinelli; M. Gutsche; M. Kehl; N. Zach; R. Hazelden

2011-01-01

167

Monolithic oxide-metal composite thermoelectric generators for energy harvesting  

NASA Astrophysics Data System (ADS)

Monolithic oxide-metal composite thermoelectric generators (TEGs) were fabricated using multilayer co-fired ceramic technology. These devices consisted of Ni0.9Mo0.1 and La0.035Sr0.965TiO3 as p- and n-type thermoelectric materials, and Y0.03Zr0.97O2 was used as an insulator, sandwiched between p- and n-type layers. To co-fire dissimilar materials, p-type layers contained 20 wt. % La0.035Sr0.965TiO3; thus, these were oxide-metal composite layers. The fabricated device had 50 pairs of p-i-n junctions of 5.9 mm × 7.0 mm × 2.6 mm. The calculated maximum value of the electric power output from the device was 450 mW/cm2 at ?T = 360 K. Furthermore, this device generated 100 ?W at ?T = 10 K and operated a radio frequency (RF) transmitter circuit module assumed to be a sensor network system.

Funahashi, Shuichi; Nakamura, Takanori; Kageyama, Keisuke; Ieki, Hideharu

2011-06-01

168

Production of alloys of bismuth telluride for solar thermoelectric generators  

NASA Astrophysics Data System (ADS)

A simple and inexpensive method is described for the preparation of sintered thermoelements for use up to about 200 C, i.e., within the temperature range that is accessible using nontracking solar collectors. The method involves selecting the raw materials, weighing the constituents and melting the ingots, grinding and grading the powders, cold-pressing the thermoelements, sintering, and evaluating the thermoelectric properties. It is shown that p-type Bi(0.5)Sb(1.5)Te(3) containing 0.05% atomic Pb, and n-type B(2)Te(2.7)Se(0.3) containing 0.2% atomic S are most suitable for operation between 30 and 170 C (i.e., at a mean temperature of 100 C). The Seebeck coefficient, electrical conductivity, and figure of merit are measured between 15 and 200 C using apparatus based on Harman's technique (1958), account being taken of radiation losses. It is shown that even though the thermoelements are porous, their thermoelectric figures of merit compare well with the values obtained with hot-pressed material of higher density. Thermoelements prepared by the method described have been fitted into a solar generator which has been operated for six months without any signs of aging.

Durst, T.; Goldsmid, H. J.; Harris, L. B.

1981-08-01

169

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

170

Thermoelectric materials 1998 -- The next generation materials for small-scale refrigeration and power generation applications  

SciTech Connect

Thermoelectric materials are used in a wide variety of applications related to small-scale solid-state refrigeration or power generation. Over the past 30 years, alloys based on the Bi-Te compounds (refrigeration) [(Bi[sub 1[minus]x]Sb[sub x])[sub 2] (Te[sub 1[minus]x]Se[sub x])[sub 3

Tritt, T.M. (ed.) (Clemson Univ., SC (United States)); Kanatzidis, M.G. (ed.) (Michigan State Univ., East Lansing, MI (United States)); Mahan, G.D. (ed.) (Univ. of Tennessee, Knoxville, TN (United States)); Lyon, H.B. Jr. (ed.) (Marlow Industries, Dallas, TX (United States))

1999-01-01

171

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

172

Heat-Pipe-Associated Localized Thermoelectric Power Generation System  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

173

Heat-Pipe-Associated Localized Thermoelectric Power Generation System  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

174

Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part I: Numerical Modeling and Baseline Model Analysis  

NASA Astrophysics Data System (ADS)

A numerical model has been developed to simulate coupled thermal and electrical energy transfer processes in a thermoelectric generator (TEG) designed for automotive waste heat recovery systems. This model is capable of computing the overall heat transferred, the electrical power output, and the associated pressure drop for given inlet conditions of the exhaust gas and the available TEG volume. Multiple-filled skutterudites and conventional bismuth telluride are considered for thermoelectric modules (TEMs) for conversion of waste heat from exhaust into usable electrical power. Heat transfer between the hot exhaust gas and the hot side of the TEMs is enhanced with the use of a plate-fin heat exchanger integrated within the TEG and using liquid coolant on the cold side. The TEG is discretized along the exhaust flow direction using a finite-volume method. Each control volume is modeled as a thermal resistance network which consists of integrated submodels including a heat exchanger and a thermoelectric device. The pressure drop along the TEG is calculated using standard pressure loss correlations and viscous drag models. The model is validated to preserve global energy balances and is applied to analyze a prototype TEG with data provided by General Motors. Detailed results are provided for local and global heat transfer and electric power generation. In the companion paper, the model is then applied to consider various TEG topologies using skutterudite and bismuth telluride TEMs.

Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.; Meisner, Gregory P.

2013-04-01

175

Radioisotope thermoelectric generator cooling in the Shuttle bay  

NASA Technical Reports Server (NTRS)

The paper describes a Shuttle-integrated radioisotope thermoelectric generator (RTG) that consists primarily of a pump package and plumbing connected directly to the Shuttle payload heat exchanger. The RTG utilizes on-board water evaporative cooling capability, which is normally used for ascent, entry, and for supplementing the radiators. Attention is given to the RTG cooling concepts which include: (1) an active thermal cooling system (ATCS), where two Freon-21 loops operate simultaneously to transport heat from the Orbiter subsystem and payloads through liquid-to-liquid heat exchangers and pin-fin coldplates to four heat sinks, and (2) an atmosphere revitalization system (ARS) which provides for thermal, pressure, and contaminate control of the crew cabin and its equipment. The use of a payload heat exchanger to reduce weight, cost and complexity associated with an independent cooling system was investigated in detail.

Stimpson, L. D.; Levine, D. I.

1979-01-01

176

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

177

Si Thermoelectric Power Generator with an Unconventional Structure  

NASA Astrophysics Data System (ADS)

We examine the mechanical stability of an unconventional Mg2Si thermoelectric generator (TEG) structure. In this structure, the angle ? between the thermoelectric (TE) chips and the heat sink is less than 90°. We examined the tolerance to an external force of various Mg2Si TEG structures using a finite-element method (FEM) with the ANSYS code. The output power of the TEGs was also measured. First, for the FEM analysis, the mechanical properties of sintered Mg2Si TE chips, such as the bending strength and Young's modulus, were measured. Then, two-dimensional (2D) TEG models with various values of ? (90°, 75°, 60°, 45°, 30°, 15°, and 0°) were constructed in ANSYS. The x and y axes were defined as being in the horizontal and vertical directions of the substrate, respectively. In the analysis, the maximum tensile stress in the chip when a constant load was applied to the TEG model in the x direction was determined. Based on the analytical results, an appropriate structure was selected and a module fabricated. For the TEG fabrication, eight TE chips, each with dimensions of 3 mm × 3 mm × 10 mm and consisting of Sb-doped n-Mg2Si prepared by a plasma-activated sintering process, were assembled such that two chips were connected in parallel, and four pairs of these were connected in series on a footprint of 46 mm × 12 mm. The measured power generation characteristics and temperature distribution with temperature differences between 873 K and 373 K are discussed.

Sakamoto, Tatsuya; Iida, Tsutomu; Ohno, Yota; Ishikawa, Masashi; Kogo, Yasuo; Hirayama, Naomi; Arai, Koya; Nakamura, Takashi; Nishio, Keishi; Takanashi, Yoshifumi

2014-06-01

178

Fabrication and Characterization of CMOS-MEMS Thermoelectric Micro Generators  

PubMed Central

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.

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

2010-01-01

179

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

180

Enhanced efficiency of solar-driven thermoelectric generator with femtosecond laser-textured metals.  

PubMed

Through femtosecond laser irradiation, we produce in this work a unique type of surface nanostructure on Al that have enhanced absorption at UV and visible but a relatively small emissivity in infrared. By integrating this laser-treated Al to a solar-driven thermoelectric generator, we show that the thermoelectric generator integrated with the femtosecond laser-treated Al foil generates a significantly higher power than the ones without. Our study shows that our technique can dramatically enhance the efficiency of solar-driven thermoelectric devices that may lead to a leap forward in solar energy harnessing. PMID:21747551

Hwang, Taek Yong; Vorobyev, A Y; Guo, Chunlei

2011-07-01

181

Thermoelectric Alloys and Devices for Radioisotope Space Power Systems: State of the Art and Current Developments  

SciTech Connect

Lead telluride and silicon germanium type alloys have served over the past several decades as the preferred thermoelectric conversion materials for U. S. radioisotope thermoelectric generator (RTG) power systems for planetary deep space exploration missions. The Pioneer missions to Jupiter and Jupiter/Saturn and the Viking Mars Lander missions employed TAGS-2N (lead and germanium telluride derivatives) power conversion devices. Since 1976, silicon germanium (SiGe) alloys, incorporated into the unicouple device, have evolved as the thermoelectric materials of choice for U. S. RTG powered space missions. These include the U. S. Air Force Lincoln Experimental Satellites 8 & 9 for communications, in 1976, followed in 1977 by the National Aeronautics and Space Administration Voyager 1 and 2 planetary missions. In 1989, advanced SiGe RTGs were used to power the Galileo exploration of Jupiter and, in 1990, will be used to power the Ulysses investigation of the Sun. In addition, SiGe technology has been chosen to provide RTG power for the 1995 Comet Rendezvous and Asteroid Flyby mission and the 1996 Cassini Saturn orbiter mission. Summaries of the flight performance data for these systems are presented.; Current U. S. Department of Energy thermoelectric development activities include (1) the development of conversion devices based on hi-density, close packed couple arrays and (2) the development of improved performance silicon germanium type thermoelectric materials. The silicon germanium type "multicouple", being developed in conjunction with the Modular RTG program, is discussed in a companion paper. A lead telluride type close-packed module, discussed herein, offers the promise of withstanding high velocity impacts and, thus, is a candidate for a Mars Penetrator application.; Recent projects sponsored by the U. S. Department of Energy, including the Improved Thermoelectric Materials and Modular Radioisotope Thermoelectric Generator programs, have shown that improvements in silicon germanium thermoelectric energy conversion capabilities of at least 50 percent can be achieved by tailoring the characteristics of the silicon germanium alloy materials and devices. This paper compares the properties and characteristics of the SiGe alloys now being developed with those used in the operational space power system.

Barnett, W.; Dick, P.; Beaudry, B.; Gorsuch, P.; Skrabek, E.

1989-01-01

182

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

183

Thermoelectric and Hybrid Generators in Wearable Devices and Clothes  

Microsoft Academic Search

This paper discusses the necessity and ways of replacing batteries in BSNs and other wearable devices with energy scavengers. The stresses are made on thermoelectric energy converters of human body heat into electrical power and on rules of their designing. The reasons for and possible ways of hybridizing wearable thermoelectric converters with photovoltaic cells are discussed, too. The examples of

Vladimir Leonov; Chris Van Hoof; Ruud J. M. Vullers

2009-01-01

184

Modeling, experimental study on the heat transfer characteristics of thermoelectric generator  

NASA Astrophysics Data System (ADS)

This paper investigates the heat transfer characteristics of a thermoelectric generator. The influence of heat dissipation intensity to the sub-thermal resistances distribution is experimentally studied. Based on the thermal network analysis and finite time thermodynamics, an analytical model including all thermal resistances (in both thermocouples and external heat exchangers) is developed to predict the performance of the generator. The results show that the computed values of output power agree well with the experimental values. The heat transfer enhancement on the generator cold side greatly reduces the cold side temperature and thermal resistance, and obviously improves the output power. Compare with air natural convection cooling, the main thermal resistance changes from the resistance between the fins and the ambient to the thermal contact resistances between the generator and the heat sink at the conditions of forced convection and water cooling. This study may be guide the optimization of generator structure.

Zhou, Ze-Guang; Zhu, Dong-Sheng; Wu, Hong-Xia; Zhang, Hong-Sheng

2013-02-01

185

Power-Generation Performance and Durability of a Skutterudite Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

By using a p-type (La, Ba, Ga, Ti)1(Fe, Co)4Sb12 skutterudite with a dimensionless figure of merit, ZT, = 0.75 at 500°C and an n-type (Yb, Ca, Al, Ga, In)0.7(Co, Fe)4Sb12 skutterudite with ZT = 1.0 at 500°C, we fabricated a thermoelectric power-generation module capable of working at high temperatures (up to 600°C). When its hot and cold sides were at 600°C and 30°C, respectively, the power output of a 50 mm × 50 mm × 7.6 mm skutterudite module was 34 W and its thermoelectric conversion efficiency was 8%. In a durability test with the module's hot and cold sides continuously maintained at 600°C and 80°C, respectively, for 8000 h, power generation first decreased by approximately 6% in the initial 300 h then remained constant.

Ochi, T.; Nie, G.; Suzuki, S.; Kikuchi, M.; Ito, S.; Guo, J. Q.

2014-06-01

186

Small-size BiTe Thermopiles and a Thermoelectric Generator for Wearable Sensor Nodes  

Microsoft Academic Search

A wearable wireless sensor is fabricated for measuring the power generated by an embedded wrist thermoelectric generator in real life at different ambient conditions. Small thermopiles with a state-of-the-art aspect ratio of 8.9 of the BiTe thermoelectric legs with a lateral size of 0.15 mm have been fabricated in an industrial process. Composing the thermopiles into four stages gives an

V. Leonov; T. Torfs; N. V. Kukhar; C. Van Hoof; R. J. M. Vullers

187

Terahertz generation and picosecond photo-thermoelectric currents in graphene  

NASA Astrophysics Data System (ADS)

We demonstrate that THz radiation is generated in optically pumped bilayer graphene. The electro-magnetic radiation is detected via a time-domain THz spectroscopy utilizing coplanar metal stripline circuits in combination with an on-chip pump/probe scheme [1]. The striplines act as highly sensitive near-field antennae with a bandwidth of up to 1 THz. Our ultrafast experiments further clarify the optoelectronic mechanisms contributing to the photocurrent generation at graphene-metal interfaces. We verify that both built-in electric fields, similar to those in semiconductor-metal interfaces, and a photo-thermoelectric effect give rise to the photocurrent at graphene-metal interfaces at different time scales. We particularly discuss how the picosecond photocurrents in monolayer graphene depend on the geometry and the thermal coupling of the devices to the environment [2]. We acknowledge the very fruitful cooperation with L. Prechtel, S. Manus, D. Schuh, W. Wegscheider, L. Song, and P. Ajayan.[4pt] [1] L. Prechtel, L. Song, P. Ajayan, D. Schuh, W. Wegscheider, A.W. Holleitner, Nature Communications 3, 646 (2012).[0pt] [2] A. Brenneis et al. (2013).

Holleitner, Alexander

2013-03-01

188

A Power And Thermal System with Thermoelectric Generators At 930 C For Solar Probe Inside 0.1 AU  

NASA Technical Reports Server (NTRS)

The Power System for Solar Probe is required to provide an electrical power of 100 W to 200 W over a wide range of radial distances from the Sun. The distance varies from 5.2 AU (i.e., Jupiter gravity assist orbit) and 4 solar radii. The solar intensity varies by nearly 5 orders of magnitude. Radioactive Thermoelectric Generator (RTG) is one way to meet the power requirement. However, the use of an RTG presents a politically expensive risk for the mission. An alternative is a totally non-nuclear and intrinsically conservative method, which uses mostly developed technologies. This paper presents an innovative concept, which uses thermoelectric generators with a high temperature cooling system to meet the power requirement inside 0. 1 AU. In this concept, Silicon Germanium (SiGe)/Gallium Phosphorus (GaP) thermoelectric generators use the infrared radiation from the spacecraft primary heat shield as an energy source, and a liquid sodium high temperature cooling system to maintain the SiGe/GaP thermoelectric generators at 1200 K. It allows a routine access by interplanetary probes to the innermost regions of the heliosphere, which is prudent to the scientific community.

Choi, Michael K.; Powers, Edward I. (Technical Monitor)

2001-01-01

189

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

190

Model for Increasing the Power Obtained from a Thermoelectric Generator Module  

NASA Astrophysics Data System (ADS)

We have developed a model for finding the most efficient way of increasing the power obtained from a thermoelectric generator (TEG) module with a variety of operating conditions and limitations. The model is based on both thermoelectric principles and thermal resistance circuits, because a TEG converts heat into electricity consistent with these two theories. It is essential to take into account thermal contact resistance when estimating power generation. Thermal contact resistance causes overestimation of the measured temperature difference between the hot and cold sides of a TEG in calculation of the theoretical power generated, i.e. the theoretical power is larger than the experimental power. The ratio of the experimental open-loop voltage to the measured temperature difference, the effective Seebeck coefficient, can be used to estimate the thermal contact resistance in the model. The ratio of the effective Seebeck coefficient to the theoretical Seebeck coefficient, the Seebeck coefficient ratio, represents the contact conditions. From this ratio, a relationship between performance and different variables can be developed. The measured power generated by a TEG module (TMH400302055; Wise Life Technology, Taiwan) is consistent with the result obtained by use of the model; the relative deviation is 10%. Use of this model to evaluate the most efficient means of increasing the generated power reveals that the TEG module generates 0.14 W when the temperature difference is 25°C and the Seebeck coefficient ratio is 0.4. Several methods can be used triple the amount of power generated. For example, increasing the temperature difference to 43°C generates 0.41 W power; improving the Seebeck coefficient ratio to 0.65 increases the power to 0.39 W; simultaneously increasing the temperature difference to 34°C and improving the Seebeck coefficient ratio to 0.5 increases the power to 0.41 W. Choice of the appropriate method depends on the limitations of system, the cost, and the environment.

Huang, Gia-Yeh; Hsu, Cheng-Ting; Yao, Da-Jeng

2014-06-01

191

Thermal--Photovoltaic Hybrid Solar Generator Using Thin-Film Thermoelectric Modules  

NASA Astrophysics Data System (ADS)

We fabricated thin-film thermoelectric modules for thermal--photovoltaic hybrid solar generator. Bi0.5Sb1.5Te3 (p-type) and Bi2Te2.7Se0.3 (n-type) thermoelectric thin films were deposited by radio-frequency magnetron sputtering method and patterned to form plane-type thermoelectric modules using lift-off technique. The hybrid module consisted of the thin-film thermoelectric module, a photovoltaic module, a hot mirror, and a near-infrared (NIR) focusing lens. NIR light, which does not contribute to photovoltaic conversion, was separated from solar light using the hot mirror. When the NIR light was focused onto the hot side of the thermoelectric module by the lens, the open voltage generated by the thin-film thermoelectric generator was 78 mV. The total open voltage of the thermal--photovoltaic hybrid generator increased by 1.3% compared to that of the photovoltaic module alone.

Mizoshiri, Mizue; Mikami, Masashi; Ozaki, Kimihiro

2012-06-01

192

Optimization and fabrication of thick flexible polymer based micro thermoelectric generator  

Microsoft Academic Search

We present a novel polymer based wafer level fabrication process for micro thermoelectric generators (?TEGs) for the application on non-planar surfaces. The generators are fabricated by subsequent electrochemical deposition (ECD) of Cu and Ni in a 190-?m thick flexible polymer mold formed by photolithographic (PL) patterning of SU-8. First generators were tested and characterized. The TEG generated a power of

Wulf Glatz; Simon Muntwyler; Christofer Hierold

2006-01-01

193

High-performance flat-panel solar thermoelectric generators with high thermal concentration  

NASA Astrophysics Data System (ADS)

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1?kW?m-2) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity.

Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J. Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

2011-07-01

194

Marine Thermoelectric Devices and Installations.  

National Technical Information Service (NTIS)

Contents: Marine thermoelectric plant operating conditions and principles of regulation (Thermoelectric generator operating conditions and characteristics, Principles of regulation of marine thermoelectric units); Prospects for the use of thermoelectric d...

Y. G. Manasyan

1970-01-01

195

Technical issues surrounding continued supply of the radiosotope thermoelectric generators for NASA programs  

SciTech Connect

The world's first [open quotes]atomic battery[close quotes] was developed in the 1950s under the Atomic Energy Commission's Space Nuclear Auxiliary Power program. A radioisotope thermoelectric generator (RTG) was unveiled for the first time in President Eisenhower's office on January 16, 1959. The new device utilized the natural decay heat of a radioactive isotope, converting the heat directly into electricity via thermoelectrics. The RTGs are compact, long-lived power sources. They have been designed to produce electricity in the 1- to 300-W range and have reliably operated for up to 27 yr, making them ideal for powering satellite electronics, especially for unmanned, deep-space exploration. Proposed generators of greater efficiency that could provide power in the 1- to 10-kW(electric) range would couple a dynamic converter to the isotopic heat source. Both are fueled with [sup 238]Pu, a transuranic isotope with a relatively short half-life of 87.7 yr. Plutonium-238 also has a very high decay heat (0.567 W/g), which enhances thermoelectric conversion. Historically, the US Department of Energy (DOE) has produced the [sup 238]Pu fuel in conjunction with defense materials production programs, minimizing unit costs. However, current changes in US defense requirements will phase out or eliminate the operation of facilities that have traditionally produced the [sup 238]Pu fuel for RTGS. The DOE is evaluating several options for future [sup 238]Pu supply, including continued domestic production, as well as the purchase of foreign fuel to meet the National Aeronautics and Space Administration (NASA) mission requirements at the most economical cost.

Cook, B.A. (Department of Energy, Germantown, MD (United States)); Hales, J.W. (Westinghouse Hanford Co., Richland, WA (United States))

1993-01-01

196

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

197

Screen printed flexible Bi2Te3-Sb2Te3 based thermoelectric generator  

NASA Astrophysics Data System (ADS)

This paper reports the fabrication and testing of Bismuth Tellurium (Bi2Te3) - Antimony Tellurium (Sb2Te3) based thermocouples using screen printing technology. In this study, screen printable thermoelectric pastes were developed and the transport properties of cured material were measured. The dimension of each planer thermoleg is 39.3 mm × 3 mm with a thickness of 67 ?m for Bi2Te3 leg and 62 ?m for Sb2Te3 leg. A single thermocouple with this dimension can generate a voltage of 6 mV and a peak output power of 48 nW at a temperature difference of 20°C. The calculated Seebeck coefficient of a single thermocouple is in the range of 262 - 282 ?V/K. The Seebeck coefficient at room temperature were measured to be -134 - -119 ?V/K and 128 - 134 ?V/K for Bi2Te3 and Sb2Te3 respectively. This work demonstrates that the low-cost screen printing technology and low-temperature materials are promising for the fabrication of flexible thermoelectric generators (TEGs).

Cao, Zhuo; Koukharenko, E.; Tudor, M. J.; Torah, R. N.; Beeby, S. P.

2013-12-01

198

Comparison of DC-DC-converter architectures of power management circuits for thermoelectric generators  

Microsoft Academic Search

Future wireless sensor nodes will, for certain applications, require only a few microwatts of energy. Micro-machined thermoelectric generators can produce such amount of electrical energy, but variations in the generated power and voltage make a power management circuit necessary to generate a suitable power supply for the sensor node. This paper compares 2 options for such a circuit. We present

I. Doms; Merken; C. Van Hoof

2007-01-01

199

Design and testing of a locally made loop-type thermosyphonic heat sink for stove-top thermoelectric generators  

Microsoft Academic Search

The performance of a thermoelectric generator, among other aspects, depends on the use of an effective heat sink. While forced cooling using either air or water (or other coolants) is efficient, it is parasitic on the generated power and\\/or bulky and inconvenient. Heat pipes are known to be highly effective heat transport devices. Coupled to a thermoelectric generator, these can

R. Y. Nuwayhid; R. Hamade

2005-01-01

200

Developments in thermoelectrically cooled PIN and CZT detectors  

SciTech Connect

A compact, high-energy-resolution X-ray and gamma-ray spectroscopy system has been developed using thermoelectrically cooled detectors to combine excellent energy resolution and convenient operation. A Si PIN diode is used for low-energy X rays, while a Cd{sub 1{minus}x}Zn{sub x}Te (CZT) detector is used for higher-energy photons. Cooling is totally transparent to the user, so the system operates as a room temperature system, although the detector itself is cooled for improved performance. The heart of the XR-100 is a hybrid package containing the thermoelectrically cooled detector and feedback components. The detectors are used with a charge-sensitive preamplifier and a seven-pole quasi-triangular shaper with active baseline restoration, pileup rejection, and rise-time discrimination.

Redus, R.H.; Pantazis, J.A.; Huber, A.C.

1998-12-31

201

Development of Thick-Film Thermoelectric Microcoolers Using Electrochemical Deposition  

NASA Technical Reports Server (NTRS)

Advanced thermoelectric microdevices integrated into thermal management packages and low power, electrical source systems are of interest for a variety of space and terrestrial applications. By shrinking the size of the thermoelements, or legs, of these devices, it becomes possible to handle much higher heat fluxes, as well as operate at much lower currents and higher voltages that are more compatible with electronic components. The miniaturization of state-of-the-art thermoelectric module technology based on Bi2Te3 alloys is limited due to mechanical and manufacturing constraints for both leg dimensions (100-200 gm thick minimum) and the number of legs (100-200 legs maximum). We are investigating the development of novel microdevices combining high thermal conductivity substrate materials such as diamond, thin film metallization and patterning technology, and electrochemical deposition of thick thermoelectric films. It is anticipated that thermoelectric microcoolers with thousands of thermocouples and capable of pumping more than 200 W/sq cm over a 30 to 60 K temperature difference can be fabricated. In this paper, we report on our progress in developing an electrochemical deposition process for obtaining 10-50 microns thick films of Bi2Te3 and its solid solutions. Results presented here indicate that good quality n-type Bi2Te3, n-type Bi2Te(2.95)Se(0.05) and p-type Bi(0.5)Sb(1.5)Te3 thick films can be deposited by this technique. Some details about the fabrication of the miniature thermoelements are also described.

Fleurial, J.-P.; Borshchevsky, A.; Ryan, M. A.; Phillips, W. M.; Snyder, J. G.; Caillat, T.; Kolawa, E. A.; Herman, J. A.; Mueller, P.; Nicolet, M.

2000-01-01

202

Regime characteristics of a solar thermoelectric generator and comparison of experimental and calculated data  

SciTech Connect

Experiments undertaken to verify predicted solar thermoelectric generator performance are described. The powder metallurgy process for production of Bi-Te-Se-negative and Bi-Te-Sb positive legs of the thermoelectric generator is reviewed, as is the fabrication of the generator. Illuminance, varied according to flux data from the Azerbaidzhan SSR, was provided by a searchlight with a focal-spot maximum heat of 300 C. Volt-ampere characteristics of the thermopiles were determined for various temperature differentials, and the efficiencies were calculated. Both capacity and efficiency were found to rise linearly with increasing temperature. Performances determined from simulation of three actual 12-hour periods agreed well with predicted values.

Movsumov, E.A.; Bairamov, A.M.

1980-01-01

203

Small size Pu238-based radionuclide thermoelectric generators - Status, applications and prospects of use  

NASA Astrophysics Data System (ADS)

Pu238O2 based radionuclide heat source (RHS) structures of heating capacity ranging from 0.1 W to 100 W have been developed. The reliability of these structures has been evaluated with a large number of comprehensive tests. Data for the RHS are given. Prospects for the development of small-size radionuclide thermoelectric generators (RTGs) of electric power ranging from 10-3 to 10 W, using the RHS, are identified. For small-size RTGs developed in the USSR, power capacity ranges from 50 to 100 kWh/kg, exceeding the power capacity of lithium cells by a factor of 200 at the minimum. Applications of RTGs of up to 10 W electric power are believed to be promising as cheap and ecologically clean sources of electric energy.

Pustovalov, A. A.; Lazarenko, Iu. V.; Shapovalov, V. P.

204

Problems of designing radioisotope thermoelectric power generators with a service life of decades for use in outer space exploration vehicles  

NASA Astrophysics Data System (ADS)

The present work deals with the feasibility of developing a radioisotope thermoelectric power generator (RTPG) capable of operating unattended in outer space over a period of several decades, among other things, on the basis of chemical compounds that occur in meteoric matter. The possibilities for solving problems related to the production of three-dimensional materials and to thermoelement interconnections are discussed. The implementation of nanotechnology will allow one to achieve an increase in the efficiency of a RTPG by 15% and higher.

Prilepo, Yu. P.; Pustovalov, A. A.; Sinyavskiy, V. V.; Sudak, N. M.; Yatsenko, O. B.

2012-12-01

205

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

Microsoft Academic Search

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

1997-01-01

206

Efficiency determination and general characterization of thermoelectric generators using an absolute measurement of the heat flow  

Microsoft Academic Search

An apparatus for measuring the conversion efficiency ? and several further key properties of thermoelectric generators is presented. To achieve highest reliability and accuracy the crucial determination of the thermal energy that is supplied to the generator is done by an absolute method, i.e. by measuring the electrical power that is dissipated in a thermally guarded resistive heater. The accuracy

L Rauscher; S Fujimoto; H T Kaibe; S Sano

2005-01-01

207

Thermoelectric power generator design and selection from TE cooling module specifications  

Microsoft Academic Search

There are many applications where thermoelectric (TE) coolers can be used effectively as power generators. In fact, where temperatures are less than 500 K, TE cooling modules are the best choice for power generation, whether it be from a cost or performance standpoint. The literature available on this subject is scarce and very limited in scope. This paper describes the

Richard J. Buist; Paul G. Lau

1997-01-01

208

State of the Art of Thermoelectric Generators Based on Heat Recovered from the Exhaust Gases of Automobiles  

Microsoft Academic Search

The recovering of heat from exhaust gases in automobiles is a typical application of electricity generation using thermoelectricity. This paper is focused on reviewing the main characteristics and evolution of the different investigations performed over the last three decades concerning the use of thermoelectric generation using the heat from the exhaust gases produced in the combustion process of an automobile.

Jorge Vázquez; Miguel A. Sanz-Bobi; Rafael Palacios; Antonio Arenas; Alberto Aguilera

209

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

210

A local selection criterion for the composition of graded thermoelectric generators  

SciTech Connect

We present a procedure that locally determines the composition (from a given set of available materials) of a segmented or graded thermoelectric generator leg in order to maximize its output power to a matched load. The method is based on a new interpretation of the electrical output relation, which is organized to resemble a differential output power along the device coordinate. The procedure is applied to calculate the segment length and output power of a segmented bismuth-telluride/iron-disilicide based thermoelectric generator leg. {copyright} {ital 1998 American Institute of Physics.}

Schilz, J.; Helmers, L.; Mueller, W.E.; Niino, M. [National Aerospace Laboratory (NAL), Kakuda Research Center, Koganezawa 1, Kimigaya, Kakuda-City, Miyagi-Pref. 981-15 (Japan)] [National Aerospace Laboratory (NAL), Kakuda Research Center, Koganezawa 1, Kimigaya, Kakuda-City, Miyagi-Pref. 981-15 (Japan)

1998-01-01

211

Exhaust gas bypass valve control for thermoelectric generator  

DOEpatents

A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

Reynolds, Michael G; Yang, Jihui; Meisner, Greogry P.; Stabler, Francis R.; De Bock, Hendrik Pieter (Peter) Jacobus; Anderson, Todd Alan

2012-09-04

212

A Thermoelectric Generator Concept Using a p-n Junction: Experimental Proof of Principle  

NASA Astrophysics Data System (ADS)

Conventional thermoelectric generators (TEGs) use single p- and n-doped legs for thermoelectric energy harvesting. We explore a concept using thermoelectric p- n junctions made from densified silicon nanoparticles. The nanoparticle powder was synthesized in a microwave plasma reactor using silane, diborane, and phosphine as precursors. To achieve a bulk sample with a p- n junction, a layer of boron-doped nanoparticle powder was stacked on a layer of phosphorus-doped powder and compacted by current-activated pressure- assisted densification. To use the p- n structure as a TEG, a temperature gradient was applied along the p- n junction. It is expected that this temperature gradient leads to electron-hole pair generation and separation in the junction, and diffusion of the charge carriers. A reference method was used to characterize the open-circuit voltage of the p- n junction TEG.

Becker, André; Chavez, Ruben; Petermann, Nils; Schierning, Gabi; Schmechel, Roland

2013-07-01

213

Complex thermoelectric materials.  

PubMed

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 of modern synthesis and characterization techniques, particularly for nanoscale materials, a new era of complex thermoelectric materials is approaching. We review recent advances in the field, highlighting the strategies used to improve the thermopower and reduce the thermal conductivity. PMID:18219332

Snyder, G Jeffrey; Toberer, Eric S

2008-02-01

214

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

215

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

216

A prototype on-line work procedure system for radioisotope thermoelectric generator production  

SciTech Connect

An on-line system to manage work procedures is being developed to support radioisotope thermoelectric generator (RTG) assembly and testing in a new production facility. This system implements production work procedures as interactive electronic documents executed at the work site with no intermediate printed form. It provides good control of the creation and application of work procedures and provides active assistance to the worker in performing them and in documenting the results. An extensive prototype of this system is being evaluated to ensure that it will have all the necessary features and that it will fit the user's needs and expectations. This effort has involved the Radioisotope Power Systems Facility (RPSF) operations organization and technology transfer between Westinghouse Hanford Company (Westinghouse Hanford) and EG G Mound Applied Technologies Inc. (Mound) at the US Department of Energy (DOE) Mound Site. 1 ref.

Kiebel, G.R.

1991-09-01

217

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

218

Controls on Water Use for Thermoelectric Generation: Case Study Texas, U.S.  

PubMed Central

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 km3), accounting for ?4% of total state water consumption. High water withdrawals (26.2 maf, 32.3 km3) 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.

2013-01-01

219

Preliminary Safety Analysis Report and Design Review of the 2 KW(e) Radioisotope Thermoelectric Generator.  

National Technical Information Service (NTIS)

A Preliminary Safety Analysis Report (PSAR) and Design Review have been conducted for the 2 KW(e) Radioisotope Thermoelectric Generator (RTG). The objective of the PSAR was to appraise the risk to public health and safety resulting from the handling, tran...

1975-01-01

220

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

National Technical Information Service (NTIS)

We report the results of the fabrication and testing of a thermoelectric power generation module. The module was fabricated using a new flip-chip module assembly technique that is scalable, modular, and results in a low value of contact resistivity (less ...

B. Geil B. Morgan N. K. Dhar P. J. Taylor

2008-01-01

221

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

National Technical Information Service (NTIS)

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 resist...

N. S. Prasad P. J. Taylor S. Kutcher S. B. Trivedi

2010-01-01

222

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

Microsoft Academic Search

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

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

1996-01-01

223

A Seamless Mode Transfer Maximum Power Point Tracking Controller for Thermoelectric Generator Applications  

Microsoft Academic Search

A boost-cascaded-with-buck converter based power conditioning system employing a seamless mode transfer maximum power point tracking controller is proposed to maximize energy production of a thermoelectric generator while balancing the vehicle battery charging, alternator output power, and vehicle load. When a maximum power point exceeds a load demand, the proposed controller switches to a power matching mode seamlessly by a

Rae-Young Kim; Jih-Sheng Lai

2007-01-01

224

Design and fabrication of MEMS thermoelectric generators with high temperature efficiency  

Microsoft Academic Search

For MEMS devices with power consumption in the range of micro-watts, thermal energy harvesting becomes a viable candidate for power supply. This paper describes a multipurpose platform to fabricate thermoelectric generators in a combined surface and bulk micromachining process. The thermocouples are deposited by thin-film processes with high integration density on the wafer surface. To provide a large thermal contact

Till Huesgen; Peter Woias; Norbert Kockmann

2008-01-01

225

Suitability of a thermoelectric power generator for implantable medical electronic devices  

Microsoft Academic Search

Embedding a thermoelectric generator (TEG) in a biological body is a promising way to supply electronic power in the long term for an implantable medical device (IMD). The unique merit of this method lies in its direct utilization of the temperature difference intrinsically existing throughout the whole biological body. However, little is known about the practicability of such a power

Yang Yang; Xiao-Juan Wei; Jing Liu

2007-01-01

226

Design, Fabrication, and Characterization of CMOS MEMS-Based Thermoelectric Power Generators  

Microsoft Academic Search

This paper presents the design, modeling, fabrication, and characterization of CMOS microelectromechanical-systems-based thermoelectric power generators (TPGs) to convert waste heat into a few microwatts of electrical power. Phosphorus and boron heavily doped polysilicon thin films are patterned and electrically connected to consist thermopiles in the TPGs. To optimize heat flux, the thermal legs are embedded between the top and bottom

Jin Xie; Chengkuo Lee; Hanhua Feng

2010-01-01

227

Extending the Useful Life of Radioisotope Thermoelectric Generators Through Active Power Control.  

National Technical Information Service (NTIS)

The useful lift time of a Radioisotope Thermoelectric Generator (RTG) may be significantly extended by use of a 'mobile-shunt' power conditioning system in preference to the more common shunt-dissipative type. A mobile-shunt regulator has been designed wh...

A. Cherdak, B. Raab, D. Rousta

2012-01-01

228

Capacitive Power Management Circuit for Micropower Thermoelectric Generators With a 1.4 A Controller  

Microsoft Academic Search

Power autonomy is an important requirement for wireless sensor nodes. Thermoelectric generators can produce sufficient power for low power applications. Due to varying temperature, a power management circuit will be required. This paper presents such a power management circuit, realized in the AMIS I3T80 CMOS technology. It contains a Dickson charge pump with a variable number of stages as a

Inge Doms; Patrick Merken; Chris Van Hoof; Robert P. Mertens

2009-01-01

229

Using a Water Lens for Light Concentration in Thermoelectric Generation  

NASA Astrophysics Data System (ADS)

A water lens is employed to concentrate sunlight on the surface of a thermoelectric module in order to heat it. This water lens can change its shape flexibly and is adjustable to solar altitudes. The lens shape and light path were simulated for the cases when the light is incident at an angle to the water surface, parallel to the central axis of the half-cylindrical water lens, and when the light is focused on a plate. A condensing ratio larger than 70 is achieved when the incident light is closer to the normal of the water surface and if the optimal lens shape is maintained.

Ito, Keita O.; Sui, Hongtao; Hakozaki, Hidetoshi; Kinoshita, Hiroshi; Suzuki, Ryosuke O.

2014-06-01

230

Vaporization and compatibility of SiGe radioisotope thermoelectric generators.  

NASA Technical Reports Server (NTRS)

The limiting operating temperatures of SiGe thermoelectrics designed for extended operation are set by sublimation process of the elements and by considerations of their compatibility with the surrounding insulating elements. Mass spectrometric Knudsen cell and Langmuir vaporization modes of operation have been utilized in the study of the equilibrium vapor species and in the time evaluation of the sublimation process. Isothermal high-vacuum (1 ntorr) anneals of samples have extended observations to long-time spans. The time variations follow the formation of surface depletion layers due to disproportional rates of sublimation of the various species.

Staley, H. G.; Rovner, L. H.; Snowden, D.; Elsner, N. B.

1972-01-01

231

Mathematic simulation on power generation by roll cake type of thermoelectric tubes  

NASA Astrophysics Data System (ADS)

Analytical expression of electric power was deduced in case of the large-scale thermoelectric device that consists of the multiple cylindrical tubes like roll cake exposed to two thermal fluids. The output powers of the four arrangements were mathematically solved from heat transfer theory. The maximum output power of roll-cake module was practically the largest for the system of the counter flow with a single thermoelectric tube (V1C system), but 1/4 of the ideal output power (V1II system). The multiplication of thermoelectric tubes can shorten significantly the device length, although the output power decreases only a little. For example, the double vortical tubes (V2CC system) can generate 95.7% output power by 38.5% diameter, compared with the single tube (V1C system).

Suzuki, Ryosuke O.; Tanaka, Daisuke

232

Design and thermal analysis of a two stage solar concentrator for combined heat and thermoelectric power generation  

Microsoft Academic Search

A design procedure and thermal performance analysis of a two stage solar energy concentrator suited to combined heat and thermoelectric power generation are presented. The concentrator is comprised of a primary one axis parabolic trough concentrator and a second stage compound parabolic concentrator mounted at the focus of the primary. The thermoelectric device is attached to the absorber plate at

Siddig A. Omer; David G. Infield

2000-01-01

233

Thin-Film Thermoelectric Module for Power Generator Applications Using a Screen-Printing Method  

NASA Astrophysics Data System (ADS)

A new process for fabricating a low-cost thermoelectric module using a screen-printing method has been developed. Thermoelectric properties of screen-printed ZnSb films were investigated in an effort to develop a thermoelectric module with low cost per watt. The screen-printed Zn x Sb1- x films showed a low carrier concentration and high Seebeck coefficient when x was in the range of 0.5 to 0.57 and the annealing temperature was kept below 550°C. When the annealing temperature was higher than 550°C, the carrier concentration of the Zn x Sb1- x films reached that of a metal, leading to a decrease of the Seebeck coefficient. In the present experiment, the optimized carrier concentration of screen-printed ZnSb was 7 × 1018/cm3. The output voltage and power density of the ZnSb film were 10 mV and 0.17 mW/cm2, respectively, at ? T = 50 K. A thermoelectric module was produced using the proposed screen-printing approach with ZnSb and CoSb3 as p-type and n-type thermoelectric materials, respectively, and copper as the pad metal.

Lee, Heon-Bok; Yang, Hyun Jeong; We, Ju Hyung; Kim, Kukjoo; Choi, Kyung Cheol; Cho, Byung Jin

2011-05-01

234

Branched and interconnected bismuth telluride nanowire arrays for thermoelectric power generation  

NASA Astrophysics Data System (ADS)

Thermoelectric generators can be used to extract waste heat energy and convert it into usable electrical energy. For decades, the thermoelectric figure of merit (ZT), which is a function of the Seebeck coefficient, electrical conductivity and thermal conductivity, has been limited to values of about 1 for practical bulk thermoelectric materials because in bulk thermoelectric materials, the parameters of ZT are interdependent. The challenge is to find materials whose thermal and electrical properties can be altered independently. Recent progress shows that in advanced bulk materials and low dimensional systems, the electrical and thermal parameters can be modulated independently allowing us to attain ZT values >1. In principle, the nanowire topology allows manipulation of the power factor in addition to reduction in thermal conductivity by increased phonon scattering from free surfaces. The focus of this work is the fabrication of nanowire arrays that can be used to form a thermoelectric device in order to exploit the benefits offered by nanowires and increase the figure of merit of the device. Emphasis is placed on resolving challenges faced during fabrication of templates as well as the nanowires, and to achieve scalable synthesis at low cost, comparable to bulk, while retaining nanoscale control of composition. 300-350 mum thick, Branched Porous Anodic Alumina (BPAA) templates were fabricated for subsequent electrodeposition of bismuth telluride nanowires. The nanowires of diameter ˜100nm, length exceeding 100mum were fabricated using potentiostatic pulsed electrodeposition (2s-6s pulses) providing good filling factors and uniform deposition. The Bi2Te3 nanowire core was annealed in Se to form a Bi2(Se,Te)3 shell, after equilibration of point defects by annealing in a Te vapor overpressure. This structure is designed to scatter long-wavelength phonons, lowering the thermal conductivity, while electrostatically repelling electrons from the free surfaces to reduce defect scattering and enhance mobility. Thus, it is anticipated that the resulting material may exhibit enhanced ZT, forming the n-type leg of a bulk thermoelectric device.

Tewari, Pranati

235

Economic Radioisotope Thermoelectric Generator (RTG) Study. Volume I. ERTG Design. Final Report.  

National Technical Information Service (NTIS)

The objectives of this study were: (1) to develop and evaluate an ERTG design for a high power, Curium-244 fueled system based on the tubular thermoelectric module technology; (2) to prepare a program plan for the development of a flight qualified ERTG; a...

1973-01-01

236

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

237

Hardware Implementation of Maximum Power Point Tracking for Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

This work describes the practical implementation of two maximum power point tracking (MPPT) algorithms, namely those of perturb and observe, and extremum seeking control. The proprietary dSPACE system is used to perform hardware in the loop (HIL) simulation whereby the two control algorithms are implemented using the MATLAB/Simulink (Mathworks, Natick, MA) software environment in order to control a synchronous buck-boost converter connected to two commercial thermoelectric modules. The process of performing HIL simulation using dSPACE is discussed, and a comparison between experimental and simulated results is highlighted. The experimental results demonstrate the validity of the two MPPT algorithms, and in conclusion the benefits and limitations of real-time implementation of MPPT controllers using dSPACE are discussed.

Maganga, Othman; Phillip, Navneesh; Burnham, Keith J.; Montecucco, Andrea; Siviter, Jonathan; Knox, Andrew; Simpson, Kevin

2014-06-01

238

Hardware Implementation of Maximum Power Point Tracking for Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

This work describes the practical implementation of two maximum power point tracking (MPPT) algorithms, namely those of perturb and observe, and extremum seeking control. The proprietary dSPACE system is used to perform hardware in the loop (HIL) simulation whereby the two control algorithms are implemented using the MATLAB/Simulink (Mathworks, Natick, MA) software environment in order to control a synchronous buck-boost converter connected to two commercial thermoelectric modules. The process of performing HIL simulation using dSPACE is discussed, and a comparison between experimental and simulated results is highlighted. The experimental results demonstrate the validity of the two MPPT algorithms, and in conclusion the benefits and limitations of real-time implementation of MPPT controllers using dSPACE are discussed.

Maganga, Othman; Phillip, Navneesh; Burnham, Keith J.; Montecucco, Andrea; Siviter, Jonathan; Knox, Andrew; Simpson, Kevin

2014-02-01

239

Thermoelectric Power Generator Design for Maximum Power: It's All About ZT  

NASA Astrophysics Data System (ADS)

There is a significant amount of literature that discusses thermoelectric power generator (TEG) design, but much of it overly simplifies the design space and therefore the results have limited use in designing real-life systems. This paper develops a more comprehensive model of the thermal and electrical interactions of a TEG in a system with known hot-side and cold-side thermal resistances and corresponding constant system temperature differential. Two design scenarios are investigated for common TEG system applications. In one method, the power from a TEG is maximized for a given electrical load, simulating a case where the TEG is electrically in series with a known load such as a fan. In the second design scenario, the power from a TEG is maximized for a given electrical load resistance ratio, n (the ratio between the external load resistance and the internal TEG resistance), simulating an application where the TEG is electrically in series with a load-matching converter. An interesting conclusion from this work is that, in the first design scenario, the electrical load resistance ratio, n, that maximizes TEG power occurs at ?{1 + ZT} (where ZT is the thermoelectric figure of merit) instead of 1 as reported previously in literature. Equally interesting is that, if you define an analogous thermal resistance ratio, m' (representing the ratio between the TEG thermal resistance at open-circuit conditions and the system thermal resistance), the maximum power in both design scenarios occurs at ?{1 + ZT} instead of the commonly cited value of 1. Furthermore, results are presented for real-life designs that incorporate electrical and thermal losses common to realistic TEG systems such as electrical contact resistance and thermal bypass around the TEG due to sealing.

McCarty, R.

2013-07-01

240

Low cost stove-top thermoelectric generator for regions with unreliable electricity supply  

Microsoft Academic Search

During the winter months in regions where constant electric power supply cannot be relied upon, power may be derived parasitically from heating stoves. A proportion of heat from these 20–50 kW wood or diesel-heated stoves may be utilized to drive a thermoelectric generator (TEG) consisting of several commercially available low-cost modules. These are Peltier modules operating in a power generating

R. Y. Nuwayhid; D. M. Rowe; G. Min

2003-01-01

241

(Bi,Sb) 2(Te,Se) 3-based thin film thermoelectric generators  

Microsoft Academic Search

Microwatt power at relatively high voltage (order of volt) was produced by (Bi,Sb)2(Te,Se)3-based thin film thermoelectric generators (TFTEGs). The generators were composed of several layers of plate-modules. Each plate-module contained 15 p\\/n couples and was connected electrically in series or in parallel. Maximum output power varied with the square of the temperature difference. Output voltage and current were controlled by

Il-Ho Kim

2000-01-01

242

Performance optimization of a two-stage semiconductor thermoelectric-generator  

Microsoft Academic Search

A model of a two-stage semiconductor thermoelectric-generator with external heat-transfer is built. Performance of the generator, assuming Newton’s heat-transfer law applies, is analyzed using a combination of finite-time thermodynamics and non-equilibrium thermodynamics. The analytical equations about the power output versus the working electrical current, and the thermal efficiency versus working electrical-current are derived. For a fixed total heat-transfer surface-area for

Lingen Chen; Jun Li; Fengrui Sun; Chih Wu

2005-01-01

243

Capacitive Power-Management Circuit for Micropower Thermoelectric Generators with a 2.1?W Controller  

Microsoft Academic Search

Energy scavenging is an emerging method to power energy-autonomous wireless sensor systems by converting ambient environmental energy into electrical energy. Miniature as well as micro-machined thermoelectric generators (TEG) can become a suitable compact power supply for both on-the-body and industrial sensors. To minimize the overall size of the power supply, the generator has to work at its maximum power point.

I. Doms; P. Merken; R. P. Mertens; C. Van Hoof

2008-01-01

244

Coin-size coiled-up polymer foil thermoelectric power generator for wearable electronics  

Microsoft Academic Search

A coiled-up thermoelectric micro power generator is presented using metal films sputtered on a thin polyimide foil. The principle of coiling-up yields higher voltages at a smaller generator area. Design optimizations were made for maximum long-term power output using the human body as heat source. It is shown that for low-power electronics like a wrist-watch even simple materials are sufficient

J. Weber; K. Potje-Kamloth; F. Haase; P. Detemple; F. Völklein; T. Doll

2006-01-01

245

Modeling of a Thermoelectric Generator for Thermal Energy Regeneration in Automobiles  

NASA Astrophysics Data System (ADS)

In the field of passenger transportation a reduction of the consumption of fossil fuels has to be achieved by any measures. Advanced designs of internal combustion engine have the potential to reduce CO2 emissions, but still suffer from low efficiencies in the range from 33% to 44%. Recuperation of waste heat can be achieved with thermoelectric generators (TEGs) that convert heat directly into electric energy, thus offering a less complicated setup as compared with thermodynamic cycle processes. During a specific driving cycle of a car, the heat currents and temperature levels of the exhaust gas are dynamic quantities. To optimize a thermoelectric recuperation system fully, various parameters have to be tested, for example, the electric and thermal conductivities of the TEG and consequently the heat absorbed and rejected from the system, the generated electrical power, and the system efficiency. A Simulink model consisting of a package for dynamic calculation of energy management in a vehicle, coupled with a model of the thermoelectric generator system placed on the exhaust system, determines the drive-cycle-dependent efficiency of the heat recovery system, thus calculating the efficiency gain of the vehicle. The simulation also shows the temperature drop at the heat exchanger along the direction of the exhaust flow and hence the variation of the voltage drop of consecutively arranged TEG modules. The connection between the temperature distribution and the optimal electrical circuitry of the TEG modules constituting the entire thermoelectric recuperation system can then be examined. The simulation results are compared with data obtained from laboratory experiments. We discuss error bars and the accuracy of the simulation results for practical thermoelectric systems embedded in cars.

Tatarinov, Dimitri; Koppers, M.; Bastian, G.; Schramm, D.

2013-07-01

246

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

247

Printed Se-Doped MA n-Type Bi2Te3 Thick-Film Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

In this work, we highlight new materials processing developments and fabrication techniques for dispenser-printed thick-film single-element thermoelectric generators (TEG). Printed deposition techniques allow for low-cost and scalable manufacturing of microscale energy devices. This work focuses on synthesis of unique composite thermoelectric systems optimized for low-temperature applications. We also demonstrate device fabrication techniques for high-density arrays of high-aspect-ratio planar single-element TEGs. Mechanical alloyed (MA) n-type Bi2Te3 powders were prepared by taking pure elemental Bi and Te in 36:64 molar ratio and using Se as an additive. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to characterize the as-milled powders to confirm the Bi2Te3 phase formation and particle size below 50 ?m. Thermoelectric properties of the composites were measured from room temperature to 100°C. We achieved a dimensionless figure of merit ( ZT) of 0.17 at 300 K for MA n-type Bi2Te3-epoxy composites with 2 wt.% Se additive. A 20 single-leg TEG prototype with 5 mm × 400 ?m × 120 ?m printed element dimensions was fabricated on a polyimide substrate with evaporated gold contacts. The prototype device produced a power output of 1.6 ?W at 40 ?A and 40 mV voltage for a temperature difference of 20°C.

Madan, Deepa; Chen, Alic; Wright, Paul K.; Evans, James W.

2012-06-01

248

Modeling and Simulations on the Intramural Thermoelectric Generator of Lower-Re-fluid  

NASA Astrophysics Data System (ADS)

The thermoelectric conversion with lower Renault number (Re) fluid, such as waste heat from industry boiler, and engine's circled cooling water, which can be designed as intramural generator structure. In this research, a thermoelectric project analysis model and the description of an intensified system are presented, its generator with the aligned or staggered platoon structure has strengthened heat-transfer property, and the heat convection coefficient ratio has increased times than plain tube; For the fluid kinetic energy's loss is influenced by the whirlpool, the pressure difference is several hundred Pa level which changes along with geometric parameters of transform components; what's more, heat transfer area increase distinctly under the same generator volume, which has built the foundation for the enhancement output electric power.

Zhang, Zheng; Zheng, Ding; Chen, Yushan

249

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

250

Use of Photothermally Generated Seebeck Voltage for Thermal Characterization of Thermoelectric Materials  

NASA Astrophysics Data System (ADS)

A simple and accurate experimental procedure to measure simultaneously the thermal properties (conductivity, diffusivity, and effusivity) of thermoelectric (TE) materials using their Seebeck voltage is proposed. The technique is based on analysis of a periodically oscillating thermoelectric signal generated from a TE material when it is thermally excited using an intensity-modulated laser source. A self-normalization procedure is implemented in the presented method using TE signals generated by changing the laser heating from one side to another of the TE material. Experiments are done on a polyaniline carbon nanohybrid (6.6 wt.% carbon nanotubes), yielding a thermal conductivity of 1.106 ± 0.001 W/m-K. The results are compared with the results from photothermal infrared radiometry experiments.

Kuriakose, Maju; Depriester, Michael; King, Roch Chan Yu; Roussel, Frédérick; Sahraoui, Abdelhak Hadj

2014-06-01

251

Enhanced performance of dispenser printed MA n-type Bi?Te? composite thermoelectric generators.  

PubMed

This work presents performance advancements of dispenser printed composite thermoelectric materials and devices. Dispenser printed thick films allow for low-cost and scalable manufacturing of microscale energy harvesting devices. A maximum ZT value of 0.31 has been achieved for mechanically alloyed (MA) n-type Bi?Te?-epoxy composite films with 1 wt % Se cured at 350 °C. The enhancement of ZT is a result of increase in the electrical conductivity through the addition of Se, which ultimately lowers the sintering temperature (350 °C). A 62 single-leg thermoelectric generator (TEG) prototype with 5 mm ×700 ?m × 120 ?m printed element dimensions was fabricated on a custom designed polyimide substrate with thick metal contacts. The prototype device produced a power output of 25 ?W at 0.23 mA current and 109 mV voltage for a temperature difference of 20 °C, which is sufficient for low power generation for autonomous microsystem applications. PMID:23130550

Madan, Deepa; Wang, Zuoqian; Chen, Alic; Juang, Rei-Cheng; Keist, Jay; Wright, Paul K; Evans, Jim W

2012-11-01

252

Realization of a wearable miniaturized thermoelectric generator for human body applications  

Microsoft Academic Search

This paper presents the realization of a full-fledged wearable miniaturized thermoelectric generator (TEG) specifically engineered for human body applications. It is based on a surface micromachined poly-SiGe thermopile. In view of the adverse thermal environment on human body, special attention is paid to the optimal design for the individual thermocouple, for the thermopile featured with a rim structure standing out

Ziyang Wang; Vladimir Leonov; Paolo Fiorini; Chris Van Hoof

2009-01-01

253

A Seamless Mode Transfer Maximum Power Point Tracking Controller For Thermoelectric Generator Applications  

Microsoft Academic Search

A boost-cascaded-with-buck converter-based power conditioning system employing a seamless mode transfer maximum power point tracking controller is proposed to maximize energy production of a thermoelectric generator while balancing a vehicle battery, alternator output power, and vehicle load. When a vehicle battery is fully charged, the proposed controller switches to a power matching mode seamlessly by a dual loop control system,

Rae-Young Kim; Jih-Sheng Lai

2008-01-01

254

Conflict between internal combustion engine and thermoelectric generator during waste heat recovery in cars  

NASA Astrophysics Data System (ADS)

It is shown that an internal combustion engine and a thermoelectric generator (TEG) arranged on the exhaust pipe of this engine come into the conflict of thermal machines that is related to using the same energy resource. The conflict grows with increasing useful electric power W e of the TEG, which leads to the limitation of both the maximum TEG output power ( W {e/max}) and the possibility of waste heat recovery in cars.

Korzhuev, M. A.

2011-02-01

255

Thermoelectric-Generator-Based DC-DC Conversion Networks for Automotive Applications  

NASA Astrophysics Data System (ADS)

Maximizing electrical energy generation through waste heat recovery is one of the modern research questions within automotive applications of thermoelectric (TE) technologies. This paper proposes a novel concept of distributed multisection multilevel DC-DC conversion networks based on thermoelectric generators (TEGs) for automotive applications. The concept incorporates a bottom-up design approach to collect, convert, and manage vehicle waste heat efficiently. Several state-of-the-art thermoelectric materials are analyzed for the purpose of power generation at each waste heat harvesting location on a vehicle. Optimal materials and TE couple configurations are suggested. Moreover, a comparison of prevailing DC-DC conversion techniques was made with respect to applications at each conversion level within the network. Furthermore, higher-level design considerations are discussed according to system specifications. Finally, a case study is performed to compare the performance of the proposed network and a traditional single-stage system. The results show that the proposed network enhances the system conversion efficiency by up to 400%.

Li, Molan; Xu, Shaohui; Chen, Qiang; Zheng, Li-Rong

2011-05-01

256

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

257

New technology for microfabrication and testing of a thermoelectric device for generating mobile electrical power  

NASA Astrophysics Data System (ADS)

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 ( <= 105 ?-cm2 ). 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/cm2 was obtained from small (<100 K) temperature differences. At higher, more realistic temperature differences, ~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, Narasimha S.; Taylor, Patrick J.; Trivedi, Sudhir B.; Kutcher, Susan W.

2010-08-01

258

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

SciTech Connect

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

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

2010-09-01

259

General purpose heat source radioisotope thermoelectric generator. Book 2: Accident analysis, appendices  

NASA Astrophysics Data System (ADS)

The purpose is to document the accident scenarios and failure probabilities defined by NASA for the Space Transportation System (the Shuttle Data Book NSTS-08116 and supporting documentation) and used in the Ulysses Mission Safety Status Report (SSR). NASA utilized a systematic approach to identify the credible accident scenarios that might pose a threat to the radioisotope thermoelectric generator (RTG). First, the Shuttle system was divided into the following seven elements: (1) Launch Support Equipment (LSE); (2) Payload; (3) Orbiter; (4) External Tank (ET); (5) Solid Rocket Boosters (SRB); (6) Space Shuttle Main Engines (SSME); and (7) Range Safety System (RSS). Each element was further divided into its major components, and these components were then subdivided until all known failure modes were identified. The approach used to develop the different accident scenarios was to divide the mission into phases and subphases as necessary. The phases were keyed to specific events that resulted in significant changes in vehicle configuration and/or in the potential consequences to the RTG. After the phases were defined, the accident scenarios for each phase were analyzed by developing detailed fault trees for each of the seven major systems as applicable.

1990-01-01

260

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

261

Analysis of Thermoelectric Generator Performance by Use of Simulations and Experiments  

NASA Astrophysics Data System (ADS)

A method that enables accurate determination of contact resistances in thermoelectric generators and which gives detailed insight into how these reduce module performance is presented in this paper. To understand the importance taking thermal and electrical contact resistances into account in analysis of thermoelectric generators, full-scale modules were studied. Contact resistances were determined by means of non-linear regression analysis on the basis of results from 3D finite element simulations and experiments in a setup in which heat flow, voltage, and current were measured. Statistical evaluation showed that the model and the identified contact resistances enabled excellent prediction of performance over the entire range of operating conditions. It was shown that if contact resistances were not included in the analysis the simulations significantly over-predicted both heat flow and electric power output, and it was concluded that contact resistance should always be included in module simulations. The method presented in this paper gives detailed insight into how thermoelectric modules perform in general, and also enables prediction of potential improvement in module performance by reduction of contact resistances.

Högblom, Olle; Andersson, Ronnie

2014-06-01

262

Thin-Film Thermoelectric Modules for Power Generation Using Focused Solar Light  

NASA Astrophysics Data System (ADS)

We demonstrated the fabrication of thin-film thermoelectric generators and evaluated their generation properties using solar light as a thermal source. Thin-film elements of Bi0.5Sb1.5Te3 ( p-type) and Bi2Te2.7Se0.3 ( n-type), which were patterned using the lift-off technique, were deposited on glass substrates using radiofrequency magnetron sputtering. After annealing at 300°C, the average Seebeck coefficients of p- and n-type films were 150 ?V/K and -104 ?V/K, respectively, at 50°C to 75°C. A cylindrical lens was used to focus solar light to a line shape onto the hot side of the thin-film thermoelectric module with 15 p- n junctions. The minimum width of line-shaped solar light was 0.8 mm with solar concentration of 12.5 suns. We studied the properties of thermoelectric modules with different-sized p- n junctions on the hot side, and obtained maximum open voltage and power values of 140 mV and 0.7 ?W, respectively, for a module with 0.5-mm p- n junctions. The conversion efficiency was 8.75 × 10-4%, which was approximately equal to the value estimated by the finite-element method.

Mizoshiri, Mizue; Mikami, Masashi; Ozaki, Kimihiro; Kobayashi, Keizo

2012-06-01

263

Unified theory for inhomogeneous thermoelectric generators and coolers including multistage devices  

NASA Astrophysics Data System (ADS)

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.JAPIAU0021-897910.1063/1.1735380 31, 1 (1960)], Snyder [Phys. Rev. B1098-012110.1103/PhysRevB.86.045202 86, 045202 (2012)], and Seifert [Phys. Status Solidi APSSABA0031-896510.1002/pssa.200925460 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.

Gerstenmaier, York Christian; Wachutka, Gerhard

2012-11-01

264

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

265

Implementation of Thermoelectric Generators in Airliners for Powering Battery-Free Wireless Sensor Networks  

NASA Astrophysics Data System (ADS)

In recent years, wireless sensor networks (WSN) have been considered for various aeronautical applications to perform sensing, data processing and wireless transmission of information, without the need to add extra wiring. However, each node of these networks needs to be self-powered. Considering the critical drawbacks associated with the use of electrochemical energy sources such as narrow operating temperature range and limited lifetime, environmental energy capture allows an alternative solution for long-term, deploy and forget, WSN. In this context, thermoelectricity is a method of choice considering the implementation context. In this paper, we present hands-on experience related to on-going implementations of thermoelectric generators (TEG) in airliners. In a first part, we will explain the reasons justifying the choice of ambient energy capture to power WSN in an aircraft. Then, we will derive the general requirements applying to the functional use of TEG. Finally, in the last section, we will illustrate the above issues through practical implementations.

Dilhac, Jean-Marie; Monthéard, Romain; Bafleur, Marise; Boitier, Vincent; Durand-Estèbe, Paul; Tounsi, Patrick

2014-04-01

266

Implementation of Thermoelectric Generators in Airliners for Powering Battery-Free Wireless Sensor Networks  

NASA Astrophysics Data System (ADS)

In recent years, wireless sensor networks (WSN) have been considered for various aeronautical applications to perform sensing, data processing and wireless transmission of information, without the need to add extra wiring. However, each node of these networks needs to be self-powered. Considering the critical drawbacks associated with the use of electrochemical energy sources such as narrow operating temperature range and limited lifetime, environmental energy capture allows an alternative solution for long-term, deploy and forget, WSN. In this context, thermoelectricity is a method of choice considering the implementation context. In this paper, we present hands-on experience related to on-going implementations of thermoelectric generators (TEG) in airliners. In a first part, we will explain the reasons justifying the choice of ambient energy capture to power WSN in an aircraft. Then, we will derive the general requirements applying to the functional use of TEG. Finally, in the last section, we will illustrate the above issues through practical implementations.

Dilhac, Jean-Marie; Monthéard, Romain; Bafleur, Marise; Boitier, Vincent; Durand-Estèbe, Paul; Tounsi, Patrick

2014-06-01

267

Mathematic simulation on power generation by roll cake type of thermoelectric double cylinders  

NASA Astrophysics Data System (ADS)

Analytical expression of electric power was deduced in case of the large-scale thermoelectric device that consists of the cylindrical double tubes like roll cake and is exposed to the two thermal fluids. The output powers of 16 systems were mathematically described by the simultaneous equations based on heat exchange. The temperature profiles in the device depend on the flow directions of hot and cold fluids, but the flow directions did not change the output power. Resultantly, eight sets of solutions for the output power were deduced. The maximum output power was the largest in the two systems (V2CC-I and V2CC-II system), where two fluids flow in counter directions and one of the fluids goes into the system from the inside of the inner cylinder. These chosen systems can generate the thermoelectric power equivalent with the single cylinder system (V1C system) using only 36% material of V1C.

Suzuki, Ryosuke O.

268

n-Si-p-Si1-xGex nanowire arrays for thermoelectric power generation  

NASA Astrophysics Data System (ADS)

The output power of a discrete assembly of n-Si-p-Si1-xGex (0 ? x ? 0.4) thermoelectric generators is measured as a function of load resistance. The influence of Ge content and nanowire structures on the performance of thermoelectric devices is evaluated in measurements around room temperature. The nanowire arrays are etched using a metal induced local oxidation and etching process, based on self-assembled Ag nanoparticles and HF. The use of nanowires and SiGe with dimensions smaller than 30 ?m, is beneficial for an improvement of, at least, a factor of 10 in the output power. However, better performance improvements can be obtained by optimising the thermal and electrical contact resistances at the interfaces. Optimisation of the electrical contact results in a performance boost by a factor of 25.

Xu, Bin; Li, Chuanbo; Myronov, Maksym; Fobelets, Kristel

2013-05-01

269

Thermal Optimization of the Heat Exchanger in the Vehicular Waste-Heat Thermoelectric Generations  

NASA Astrophysics Data System (ADS)

The potential for vehicular exhaust-based thermoelectric generations (ETEGs) has been increasing with recent advances in the efficiency of thermoelectric materials. This study analyzes the thermal performance of the exhaust gas tanks in ETEGs. The thermal characteristics of the exhaust gas tanks with different internal structures and thicknesses are discussed in terms of the interface temperature and the thermal uniformity. The methods of computational fluid dynamics simulations and infrared experiments on a high- performance production engine with a dynamometer are carried out. Results indicate that the exhaust gas tank, the internal structure of which is the "fishbone" shape and the interior thickness of which is 12 mm, obtains a relatively optimal thermal performance, which can really help improve the overall efficiency of the ETEGs.

Su, C. Q.; Zhan, W. W.; Shen, S.

2012-06-01

270

Thermal Optimization of the Heat Exchanger in an Automotive Exhaust-Based Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

Recent advances in thermoelectric technologies have made exhaust-based thermoelectric generators (TEGs) promising to recover waste heat. The thermal performance of the heat exchanger in exhaust-based TEGs is studied in this work. In terms of interface temperature and thermal uniformity, the thermal characteristics of heat exchangers with different internal structures, lengths, and materials are discussed. Following computational fluid dynamics simulations, infrared experiments are carried out on a high-performance production engine with a dynamometer. Simulation and experimental results show that a plate-shaped heat exchanger made of brass with fishbone-shaped internal structure and length of 600 mm achieves a relatively ideal thermal performance, which is practically helpful to enhance the thermal performance of the TEG.

Deng, Y. D.; Liu, X.; Chen, S.; Tong, N. Q.

2013-07-01

271

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

NASA Astrophysics Data System (ADS)

There is enormous military and commercial interest in developing quiet, lightweight, and compact thermoelectric (TE) power generation systems. This paper investigates design integration and analysis of an advanced TE power generation system implementing JP-8 fueled combustion and thermal recuperation. In the design and development of this portable TE power system using a JP-8 combustor as a high-temperature heat source, optimal process flows depend on efficient heat generation, transfer, and recovery within the system. The combustor performance and TE subsystem performance were coupled directly through combustor exhaust temperatures, fuel and air mass flow rates, heat exchanger performance, subsequent hot-side temperatures, and cold-side cooling techniques and temperatures. Systematic investigation and design optimization of this TE power system relied on accurate thermodynamic modeling of complex, high-temperature combustion processes concomitantly with detailed TE converter thermal/mechanical modeling. To this end, this paper reports integration of system-level process flow simulations using CHEMCAD™ commercial software with in-house TE converter and module optimization, and heat exchanger analyses using COMSOL™ software. High-performance, high-temperature TE materials and segmented TE element designs are incorporated in coupled design analyses to achieve predicted TE subsystem-level conversion efficiencies exceeding 10%. These TE advances are integrated with a high-performance microtechnology combustion reactor based on recent advances at Pacific Northwest National Laboratory (PNNL). Predictions from this coupled simulation approach lead directly to system efficiency-power maps defining potentially available optimal system operating conditions and regimes. Further, it is shown that, for a given fuel flow rate, there exists a combination of recuperative effectiveness and hot-side heat exchanger effectiveness that provides a higher specific power output from the TE modules. This coupled simulation approach enables pathways for integrated use of high-performance combustor components, high-performance TE devices, and microtechnologies to produce a compact, lightweight, combustion-driven TE power system prototype that operates on common fuels.

Krishnan, Shankar; Karri, Naveen K.; Gogna, Pawan K.; Chase, Jordan R.; Fleurial, Jean-Pierre; Hendricks, Terry J.

2012-06-01

272

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

273

Engineering assessment of TEG and TEG/FC technology growth potential. Phase I. Engineering assessment of existing thermoelectric generator technology. Final report Jun-Sep 81  

SciTech Connect

An analysis of the likely conformance of current thermoelectric generators to the Army SLEEP ROC is provided. A feasibility analysis of the thermoelectric generator as a means of providing electricity, heating and cooling to a typical mobile teletype terminal is given. Findings relative to the thermoelectric generator as a candidate for the SLEEP ROC and as a primary energy source for a teletype terminal are given.

Lee, W.D.; Long, R.G.

1981-09-01

274

Solar thermoelectric refrigerator  

Microsoft Academic Search

It is shown that a thermoelectric generator, which draws its heat from the sun, is a particularly suitable source of electrical power for the operation of a thermoelectric refrigerator. The theory of the combined thermoelectric generator and refrigerator is derived and the ratio of the numbers of thermocouples needed for the two devices is determined. It is found that this

G. J. Vella; L. B. Harris; H. J. Goldsmid

1976-01-01

275

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

276

Titanium Disilicide as High-Temperature Contact Material for Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

Thermoelectric devices can be used to capture electric power from waste heat in a variety of applications. The theoretical efficiency rises with the temperature difference across the thermoelectric generator (TEG). Therefore, we have investigated contact materials to maximize the thermal stability of a TEG. A promising candidate is titanium disilicide (TiSi2), which has been well known as a contact material in silicon technology for some time, having low resistivity and thermal stability up to 1150 K. A demonstrator using highly doped silicon as the thermoelectric material has been integrated. A p- and an n-type wafer were oxidized and bonded. After cutting the wafer into pieces, a 200-nm-thick titanium layer was sputtered onto the edges. After a 750°C rapid thermal annealing step, the TEG legs were connected by a highly conductive TiSi2 layer. A TEG with 12 thermal couples was integrated, and its joint resistance was found to be 4.2 ?. Hence, we have successfully demonstrated a functional high-temperature contact for TEGs up to at least 900 K. Nevertheless, the actual thermal stability will be even higher. The process could be transfered to other substrates by using amorphous silicon deposited by plasma-enhanced chemical vapor deposition.

Assion, F.; Schönhoff, M.; Hilleringmann, U.

2013-07-01

277

Pressure Tuning of Thermoelectric Materials  

Microsoft Academic Search

\\u000a It is widely believed that significant improvements in the performance of thermoelectric materials are possible.1,2 The development of such improved materials could lead to revolutionary advances in many important technologies, such as refrigeration,\\u000a electric power generation, and cooling of both superconducting and conventional electronic components.2,3 Because device efficiency depends critically on the product of the thermoelectric figure of merit, Z,

T. J. Scheidemantel; J. V. Badding

278

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

279

Detailed mathematical models of a radioisotope thermoelectric generator.  

NASA Technical Reports Server (NTRS)

Two new models for the design and performance analysis of RTG's are outlined in this paper. The first model assumes a small-signal transient-type calculational sequence that permits the separation of steady-state operation of the generator from its dynamic behavior. The second model uses a numerical (finite difference) solution of the performance equations of the RTG. Both models enable the investigation of transient and steady-state performance of RTG's. Simplifying assumptions have been kept to a minimum in the new RTG models and these models enable the inclusion of generator end losses, axial temperature gradients and heat interchange between thermoelements and thermal insulation in RTG performance calculations in a self-consistent manner.

Dewinter, F.; Raag, V.

1972-01-01

280

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.

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

2013-01-01

281

Thermoelectric power conversion in space  

NASA Technical Reports Server (NTRS)

A radiatively-heated multicouple for use in the next generation of radioisotope thermoelectric generator (RTG) will employ 20 individual couples within a single cell, so that 40 n- and p-semiconductor legs will be interconnected in series. At the hot end of the RTG, the legs will be electrically interconnected using silicon molybdenum; on the cold side, the legs are interconnected by tungsten. The entire cell is then mechanically attached to a radiator, which conducts heat away and radiates it into space. Deep-space applications will use RTGs developed for vacuum operation; thermoelectric converter power systems using a unicouple configuration have flown on such missions as Pioneers 10 and 11, which used lead telluride thermoelectric converters, and Voyagers I and II, which used silicon germanium-based thermoelectrics.

Awaya, Henry I.; Ewell, Richard; Nesmith, Bill; Vandersande, James

1990-01-01

282

Radioisotope Thermoelectric Generators Based on Segmented BiTe/PbTe-BiTe/TAGS/PbSnTe  

NASA Astrophysics Data System (ADS)

This paper reports on Phase 1 of a multifaceted effort to develop a more efficient radioisotope thermoelectric generator (RTG) for future NASA missions. The conversion efficiency goal is 10% or higher at a power level of 20 watt or higher. The thermoelectric (T/E) efficiency achievable with present T/E materials is about 8% for favorable temperatures. Thermoelectric converter designs, T/E material properties, and T/E couple thermal and electrical performance were investigated in Phase 1 of this program to find paths to improve conversion efficiency. T/E properties can be improved by optimizing the composition of the materials and by improving the micro structural characteristics such as homogeneity, grain size, and phases present. T/E couple performance can be improved by reducing the electrical and thermal contact resistances of the couple and within the segmented T/E elements. Performance and reliability improvements can be achieved by reducing the thermo-mechanical stresses, improving the quality of the bonds and interfaces, minimizing the number of required bonds, and reducing the degradation rates of both the T/E materials and the bonds. This paper focuses on one portion of the activity, i.e., the design of a small converter. In the converter design effort, a prototypic 20-watt device, suitable for use with a single general-purpose heat source (GPHS), was built using an optimized converter design of segmented thermoelectric elements of heritage composition. The 20-watt prototype achieved the power predicted for the test conditions. The chosen couple design used segmented BiTe/PbTe for the n-type element and BiTe/TAGS/PbSnTe, for the p-type T/E element. Use of the BiTe segment exploits the opportunity of the small RTG to operate at lower heat rejection temperatures and results in much higher conversion efficiency, the main objective of the NASA program. Long term data on similarly segmented couples at Teledyne together with the 20-watt module test results confirm that a small RTE based on a single GPHS and heritage materials can now reach a high readiness level, without need of material improvement. It is also anticipated that a more efficient version will be developed in the future that will also incorporate the material and process improvements identified in this phase.

McAlonan, Malachy; Patel, Kalpesh; Cummer, Keith

2006-01-01

283

Radioisotope thermoelectric generator package o-ring seal material validation testing  

NASA Astrophysics Data System (ADS)

The Radioisotope Thermoelectric Generator Package O-Ring Seal Material Validation Test was conducted to validate the use of the Butyl material as a primary seal throughout the required temperature range. Three tests were performed at (I) 233 K (-40 °F), (2) a specified operating temperature, and (3) 244 K (-20 °F) before returning to room temperature. Helium leak tests were performed at each test point to determine seal performance. The two major test objectives were to establish that butyl rubber material would maintain its integrity under various conditions and within specified parameters and to evaluate changes in material properties.

Adkins, Harold E.; Ferrell, Patrick C.; Knight, Ronald C.

1995-01-01

284

(Design, fabricate, and provide engineering support for radiosotope thermoelectric generators for NASA's CRHF AND CASSINI missions)  

SciTech Connect

The technical progress achieved during the period 11 January through 31 March 1991 on Contract DE-AC03-91SF18852.000 Radioisotope Thermoelectric Generators and ancillary activities is described. The system contract consists of the following tasks: (1) Spacecraft Integration and Liaison; (2) Engineering Support; (3) Safety; (4) Qualify Unicouple Fabrication; (5) ETG Fabrication, Assembly and Test; (6) GSE; (7) RTG Shipping and Launch Support; (8) Designs, Reviews, and Mission Applications; (9) Project Management, Quality Assurance and Reliability; and (H) CAGO Acquisition (Capital Funds). The progress achieved is broken down into these tasks. 1 tab.

Not Available

1991-01-01

285

Development of Improved Thermoelectric Cooling Materials for Ground Air Conditioners.  

National Technical Information Service (NTIS)

The extent of the single-phase region near the AgSbTe2 composition in the Ag-Sb- Te ternary system was estimated, and preliminary evaluation was made of the thermoelectric properties of alloys in this region. The highest room-temperature figure of merit o...

E. H. Lougher E. P. Stambaugh R. Simon W. D. Lemke R. J. Buist

1967-01-01

286

Cost-Performance Analysis and Optimization of Fuel-Burning Thermoelectric Power Generators  

NASA Astrophysics Data System (ADS)

Energy cost analysis and optimization of thermoelectric (TE) power generators burning fossil fuel show a lower initial cost compared with commercialized micro gas turbines but higher operating cost per energy due to moderate efficiency. The quantitative benefit of the thermoelectric system on a price-per-energy (/J) basis lies in its scalability, especially at a smaller scale (<10 kW), where mechanical thermodynamic systems are inefficient. This study is based on propane as a chemical energy source for combustion. The produced heat generates electric power. Unlike waste heat recovery systems, the maximum power output from the TE generator is not necessarily equal to the economic optimum (lowest /kWh). The lowest cost is achieved when the TE module is optimized between the maximum power output and the maximum efficiency, dependent on the fuel price and operation time duration. The initial investment (/W) for TE systems is much lower than for micro gas turbines when considering a low fractional area for the TE elements, e.g., 5% to 10% inside the module. Although the initial cost of the TE system is much less, the micro gas turbine has a lower energy price for longer-term operation due to its higher efficiency. For very long-term operation, operating cost dominates, thus efficiency and material ZT become the key cost factors.

Yazawa, Kazuaki; Shakouri, Ali

2013-07-01

287

Radioisotope thermoelectric generator load and unload sequence from the licensed hardware package system and the trailer system  

SciTech Connect

The Radioisotope Thermoelectric Generator Transportation System, designated as System 100, comprises four major systems. The four major systems are designated as the Packaging System (System 120), Trailer System (System 140), Operations and Ancillary Equipment System (System 160), including the Radioisotope Thermoelectric Generator Transportation System packaging is licensed (regularoty) hardware, certified by the U.S. Department of Energy to be in accordance with Title 10, {ital Code} {ital of} {ital Federal} {ital Regulations}, Part 71 (10 CFR 71). System 140, System 160, and System 180 are nonlicensed (nonregulatory) hardware. This paper focuses on the required interfaces and sequencing of events required by these systems and the shipping and receiving facilities in preparation of the Radioisotope Thermoelectric Generator for space flight. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}

Reilly, M.A. [Westinghouse Hanford Company, P.O. Box 1970, MSIN N1-25, Richland, Washington 99352 (United States)

1995-01-20

288

Program Final Report - Develop Thermoelectric Technology for Automotive Waste Heat Recovery  

SciTech Connect

We conducted a vehicle analysis to assess the feasibility of thermoelectric technology for waste heat recovery and conversion to useful electrical power and found that eliminating the 500 W of electrical power generated by the alternator corresponded to about a 7% increase in fuel economy (FE) for a small car and about 6% for a full size truck. Electric power targets of 300 W were established for city and highway driving cycles for this project. We obtained critical vehicle level information for these driving cycles that enabled a high-level design and performance analysis of radiator and exhaust gas thermoelectric subsystems for several potential vehicle platforms, and we identified the location and geometric envelopes of the radiator and exhaust gas thermoelectric subsystems. Based on this analysis, we selected the Chevrolet Suburban as the most suitable demonstration vehicle for this project. Our modeling and thermal analysis assessment of a radiator-based thermoelectric generator (TEG), however, revealed severe practical limitations. Specifically the small temperature difference of 100°C or less between the engine coolant and ambient air results in a low Carnot conversion efficiency, and thermal resistance associated with air convection would reduce this conversion efficiency even further. We therefore decided not to pursue a radiator-based waste heat recovery system and focused only on the exhaust gas. Our overall approach was to combine science and engineering: (1) existing and newly developed TE materials were carefully selected and characterized by the material researcher members of our team, and most of the material property results were validated by our research partners, and (2) system engineers worked closely with vehicle engineers to ensure that accurate vehicle-level information was used for developing subsystem models and designs, and the subsystem output was analyzed for potential fuel economy gains. We incorporated material, module, subsystem, and integration costs into the material selection criteria in order to balance various materials, module and subsystem design, and vehicle integration options. Our work on advanced TE materials development and on TEG system design, assembly, vehicle integration, and testing proceeded in parallel efforts. Results from our two preliminary prototype TEGs using only Bi-Te TE modules allowed us to solve various mechanical challenges and to finalize and fine tune aspects of the design and implementation. Our materials research effort led us to quickly abandon work on PbTe and focus on the skutterudite materials due to their superior mechanical performance and suitability at automotive exhaust gas operating temperatures. We synthesized a sufficiently large quantity of skutterudite material for module fabrication for our third and final prototype. Our TEG#3 is the first of its kind to contain state-of-the-art skutterudite-based TE modules to be installed and tested on a production vehicle. The design, which consisted of 24 skutterudite modules and 18 Bi-Te modules, attempted to optimize electrical power generation by using these two kinds of TE modules that have their peak performance temperatures matched to the actual temperature profile of the TEG during operation. The performance of TEG#3 was limited by the maximum temperature allowable for the Bi-Te TE modules located in the colder end of the TEG, resulting in the operating temperature for the skutterudite modules to be considerably below optimum. We measured the power output for (1) the complete TEG (25 Watts) and (2) an individual TE module series string (1/3 of the TEG) operated at a 60°C higher temperature (19 Watts). We estimate that under optimum operating temperature conditions, TEG#3 will generate about 235 Watts. With additional improvements in thermal and electrical interfaces, temperature homogeneity, and power conditioning, we estimate TEG#3 could deliver a power output of about 425 Watts.

Gregory Meisner

2011-08-31

289

Reversible Thermoelectric Nanomaterials  

Microsoft Academic Search

Irreversible effects in thermoelectric materials limit their efficiency and economy for applications in power generation and refrigeration. While electron transport is unavoidably irreversible in bulk materials, here we derive conditions under which reversible diffusive electron transport can be achieved in nanostructured thermoelectric materials. We provide a fundamental thermodynamic explanation for why the optimum density of states in a thermoelectric material

T. E. Humphrey; H. Linke

2005-01-01

290

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

291

Integrating Phase-Change Materials into Automotive Thermoelectric Generators - An Experimental Examination and Analysis of Energetic Potential Through Numerical Simulation  

NASA Astrophysics Data System (ADS)

Because the heat emitted by conventional combustion-engine vehicles during operation has highly transient properties, automotive thermoelectric generators (TEG) are intended for a particular operating state (design point). This, however, leads to two problems. First, whenever the combustion engine runs at low load, the maximum operating temperature cannot be properly utilised; second, a combustion engine at high load requires partial diversion of exhaust gas away from the TEG to protect the thermoelectric modules. An attractive means of stabilising dynamic exhaust behaviour (thereby keeping the TEG operating status at the design point for as long as possible) is use of latent heat storage, also known as phase-change materials (PCM). By positioning PCM between module and exhaust heat conduit, and choosing a material with a phase-change temperature matching the module's optimum operating temperature, it can be used as heat storage. This paper presents results obtained during examination of the effect of integration of latent heat storage on the potential of automotive TEG to convert exhaust heat. The research resulted in the development of a concept based on the initial integration idea, followed by proof of concept by use of a specially created prototype. In addition, the potential amount of energy obtained by use of a PCM-equipped TEG was calculated. The simulations indicated a significant increase in electrical energy was obtained in the selected test cycle.

Klein Altstedde, Mirko; Rinderknecht, Frank; Friedrich, Horst

2014-01-01

292

Fabrication and characterization of bismuth–telluride-based alloy thin film thermoelectric generators by flash evaporation method  

Microsoft Academic Search

Bismuth–telluride-based alloy thin film thermoelectric generators are fabricated by a flash evaporation method. We prepare Bi0.4Te3.0Sb1.6 (p-type) and Bi2.0Te2.7Se0.3 (n-type) powders for the fabrication of the flash evaporated thin films. The overall size of the thin film thermoelectric generators, which consist of seven pairs of legs connected by aluminum electrodes, is 20mm by 15mm. Each leg is 15mm long, 1mm

M. Takashiri; T. Shirakawa; K. Miyazaki; H. Tsukamoto

2007-01-01

293

Columnar thermoelectric elements of linked spheres for miniature electric generation modules  

NASA Astrophysics Data System (ADS)

Thermoelectric elements that were formed from vertically aligned microspheres were fabricated from 500-µm monosized spherical particles of Fe2VAl alloys with a particle assembly that used pulsed current micro-welding. P-n pairs of the elements consisting of three particles generated relatively large temperature differences ?T despite being 1.5 mm tall. At ?T = 19 K, the five pairs generated a voltage of 21 mV and a maximum generation power of 40 µW, which converted to 0.21 V/cm2 voltage per unit area and 0.4 mW/cm2 power density, respectively. Moreover, we demonstrated the feasibility of building a massive array with 100 elements.

Takagi, Kenta; Ozaki, Kimihiro; Kawaguchi, Yasuhiro; Yumi, Hideki

2012-05-01

294

Thermoelectric Power Generation System for Future Hybrid Vehicles Using Hot Exhaust Gas  

NASA Astrophysics Data System (ADS)

The present experimental and computational study investigates a new exhaust gas waste heat recovery system for hybrid vehicles, using a thermoelectric module (TEM) and heat pipes to produce electric power. It proposes a new thermoelectric generation (TEG) system, working with heat pipes to produce electricity from a limited hot surface area. The current TEG system is directly connected to the exhaust pipe, and the amount of electricity generated by the TEMs is directly proportional to their heated area. Current exhaust pipes fail to offer a sufficiently large hot surface area for the high-efficiency waste heat recovery required. To overcome this, a new TEG system has been designed to have an enlarged hot surface area by the addition of ten heat pipes, which act as highly efficient heat transfer devices and can transmit the heat to many TEMs. As designed, this new waste heat recovery system produces a maximum 350 W when the hot exhaust gas heats the evaporator surface of the heat pipe to 170°C; this promises great possibilities for application of this technology in future energy-efficient hybrid vehicles.

Kim, Sun-Kook; Won, Byeong-Cheol; Rhi, Seok-Ho; Kim, Shi-Ho; Yoo, Jeong-Ho; Jang, Ju-Chan

2011-05-01

295

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

296

Perfect thermal spin filter and pure spin thermoelectric generator based on a laterally coupled double quantum-dot array  

NASA Astrophysics Data System (ADS)

We report a proposal to realize a perfect thermal spin filter and a pure spin thermoelectric generator based on a laterally coupled double quantum-dot (DQD) array. It is found that the thermal conductance spectrum of the system presents a well-defined adiabatic band with very steep edges due to Fano antiresonance. Considering a Zeeman splitting, highly to 100% thermospin-polarized windows appear in the spin-splitting thermal conductance, which makes this DQD array applicable as a perfect thermal spin filter. Moreover, under some appropriate conditions, the charge thermopower is zero while the spin thermopower is not, indicating it can be used as a pure spin thermoelectric generator. More important, to achieve these thermoelectric characteristics, the DQD array does not need a very large chain length.

Fu, Hua-Hua; Yao, Kai-Lun

2013-09-01

297

High efficiency segmented thermoelectric unicouples  

NASA Astrophysics Data System (ADS)

Highly efficient, segmented thermoelectric unicouple incorporating advanced thermoelectric materials with superior thermoelectric figures of merit are currently being developed at the Jet Propulsion Laboratory (JPL). These segmented unicouples incorporate a combination of state-of-the-art thermoelectric materials based on Bi2Te3 and novel p-type Zn4Sb3, p-type CeFe4Sb12-based alloys and n-type CoSb3-based alloys developed at JPL. They can be integrated into thermoelectric power generation modules which could be used for a variety of applications making use of waste heat recovery and also potentially in Radioisotope Power Systems (RPSs) that are needed for several NASA missions planned over the next few years. These missions call for electrical power requirements ranging from 20 to 200 watts and 6 to 15 years mission duration. The resulting RPSs would not only have a high specific power (~8 We/kg) that is about twice that of the state-of-the-art Radioisotope Thermoelectric Generators (RTGs), but also a higher overall efficiency (>14%), halving the 238 PuO2 needed for a given electric power requirement. These advanced RPSs would couple the novel, segmented thermoelectric unicouples (STUs) to one or several standard General Purpose Heat Source (GPHS) modules (or bricks), depending on the electric power requirements. The advanced STUs would operate at a hot side temperature of about 1000 K, alleviating some of the concerns associated with the high temperature operation of current GPHS-RTGs (~1300 K), and at a cold side temperature of ~400 K. The latest developments in the fabrication and testing of the advanced segmented thermoelectric unicouples are presented and discussed. .

Caillat, Thierry; Borshchevsky, Alex; Snyder, Jeff; Fleurial, Jean-Pierre

2001-02-01

298

The long-term performance degradation of a radioisotope thermoelectric generator using silicon germanium  

NASA Technical Reports Server (NTRS)

The successful utilization of a radioisotope thermoelectric generator (RTG) as the power source for spaceflight missions requires that the performance of such an RTG be predictable throughout the mission. Several mechanisms occur within the generator which tend to degrade the performance as a function of operating time. The impact which these mechanisms have on the available output power of an RTG depends primarily on such factors as time, temperature and self-limiting effects. The relative magnitudes, rates and temperature dependency of these various degradation mechanisms have been investigated separately by coupon experiments as well as 4-couple and 18-couple module experiments. This paper discusses the different individual mechanisms and summarizes their combined influence on the performance of an RTG. Also presented as part of the RTG long-term performance characteristics is the sensitivity of the available RTG output power to variations of the individual degradation mechanisms thus identifying the areas of greatest concern for a successful long-term mission.

Stapfer, G.; Truscello, V. C.

1976-01-01

299

Synthetic thermoelectric materials comprising phononic crystals  

DOEpatents

Synthetic thermoelectric materials comprising phononic crystals can simultaneously have a large Seebeck coefficient, high electrical conductivity, and low thermal conductivity. Such synthetic thermoelectric materials can enable improved thermoelectric devices, such as thermoelectric generators and coolers, with improved performance. Such synthetic thermoelectric materials and devices can be fabricated using techniques that are compatible with standard microelectronics.

El-Kady, Ihab F; Olsson, Roy H; Hopkins, Patrick; Reinke, Charles; Kim, Bongsang

2013-08-13

300

Thermoelectric Conversion with Ion Conductors.  

National Technical Information Service (NTIS)

A theoretical and experimental investigation of an oxygen thermoelectric generator based on oxygen ion-conducting solid electrolyte was carried out. In this thermoelectric generator concept, oxygen is electrochemically expanded at a higher temperature T a...

A. V. Joshi

1990-01-01

301

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

302

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

303

Progress Towards a Micromachined Thermoelectric Generator using PbTe and PbSnSeTe Thin Films.  

National Technical Information Service (NTIS)

This paper presents etching techniques and metal contact resistance studies for vapor-deposited PbTe and PbSnSeTe films to enable micromachining of thermoelectric (TE) generators within integrated MEMS devices (e.g. micro heat engines, microcombustors). F...

C. D. Meyer D. P. Arnold I. Boniche N. K. Dhar P. J. Taylor

2006-01-01

304

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

305

Silicon-germanium alloys as high-temperature thermoelectric materials  

Microsoft Academic Search

The preparation and properties of silicon-germanium alloys are reviewed. Attention is given to recent developments in their technology and their potential for further improvement as high temperature thermoelectric materials is assessed. Topics discussed include basic concepts and thermoelectric phenomena, thermoelements and silicon-germanium generators, and silicon-germanium alloy preparation. Also considered are some general considerations of the thermoelectric figure of merit.

C. M. Bhandari; D. M. Rowe

1980-01-01

306

Universal thermoelectric unit  

SciTech Connect

The problems of energy supply of low power electric devices very often can be solved with thermoelectric generator even with low coefficient of performance, when other electric energy sources are not convenient. The problems of thermoelectric and construction choice for such generators are discussed in the paper. A series of domestic thermoelectric generators was designed by the authors. The work is based on designing an universal thermoelectric unit---a battery which consist of ten thermoelements. The coefficient of performance of the unit is about 4%. Any thermoelectric generator can be made as a combination of these units. Principal opportunity of production such thermoelectric generators on industrial scale was proved. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Fedorov, M.I.; Engalychev, A.E.; Zaitsev, V.K.; Kaliazin, A.E.; Solomkin, F.Y. [A. F. Ioffe Physical-Technical Institute, Politekhnicheskaya 26, St. Petersburg, 194021 (Russian Federation)

1994-08-10

307

Thermoelectric Outer Planets Spacecraft (TOPS) electronic packaging and cabling development summary report  

NASA Technical Reports Server (NTRS)

Electronic packaging and cabling activities performed in support of the Thermoelectric Outer Planets Spacecraft (TOPS) Advanced Systems Technology (AST) project are detailed. It describes new electronic compartment, electronic assembly, and module concepts, and a new high-density, planar interconnection technique called discrete multilayer (DML). Development and qualification of high density cabling techniques, using small gage wire and microminiature connectors, are also reported.

Dawe, R. H.; Arnett, J. C.

1974-01-01

308

Effective thermal conductivity in thermoelectric materials  

NASA Astrophysics Data System (ADS)

Thermoelectric generators (TEGs) are solid state heat engines that generate electricity from a temperature gradient. Optimizing these devices for maximum power production can be difficult due to the many heat transport mechanisms occurring simultaneously within the TEG. In this paper, we develop a model for heat transport in thermoelectric materials in which an ``effective thermal conductivity'' (?eff) encompasses both the one dimensional steady-state Fourier conduction and the heat generation/consumption due to secondary thermoelectric effects. This model is especially powerful in that the value of ?eff does not depend upon the operating conditions of the TEG but rather on the transport properties of the TE materials themselves. We analyze a variety of thermoelectric materials and generator designs using this concept and demonstrate that ?eff predicts the heat fluxes within these devices to 5% of the exact value.

Baranowski, Lauryn L.; Jeffrey Snyder, G.; Toberer, Eric S.

2013-05-01

309

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

DOEpatents

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

310

Variable cooling circuit for thermoelectric generator and engine and method of control  

DOEpatents

An apparatus is provided that includes an engine, an exhaust system, and a thermoelectric generator (TEG) operatively connected to the exhaust system and configured to allow exhaust gas flow therethrough. A first radiator is operatively connected to the engine. An openable and closable engine valve is configured to open to permit coolant to circulate through the engine and the first radiator when coolant temperature is greater than a predetermined minimum coolant temperature. A first and a second valve are controllable to route cooling fluid from the TEG to the engine through coolant passages under a first set of operating conditions to establish a first cooling circuit, and from the TEG to a second radiator through at least some other coolant passages under a second set of operating conditions to establish a second cooling circuit. A method of controlling a cooling circuit is also provided.

Prior, Gregory P

2012-10-30

311

The application of solar thermoelectric generators in near-sun missions  

NASA Technical Reports Server (NTRS)

Future planetary near-sun missions, such as those studied for low-altitude Mercury Orbiters, introduce challenges in the selection of appropriate power sources. Study results have shown that conventional silicon solar array technology is not adequate to produce power because of expected temperatures which range from -90 C to +285 C in about 40 to 50 minutes for 16 sun eclipses/day. The solar thermoelectric generator (STG), which requires relatively high temperatures, is being considered as a replacement power source. The complete STG consists of a solar concentrator and multiple thermopiles, each containing numerous thermocouples and thermal insulation material. Articulation of the STG design configurations is required at 0.45 AU to acquire maximum incident radiation and at 0.3 AU to reduce the higher incident radiation. STG thermal input to the spacecraft as it orbits Mercury (including sun eclipses) is insignificant.

Raag, V.; Hankins, L.; Swerdling, M.; Ivanoff, R.

1978-01-01

312

Spin-on-doping for output power improvement of silicon nanowire array based thermoelectric power generators  

NASA Astrophysics Data System (ADS)

The output power of a silicon nanowire array (NWA)-bulk thermoelectric power generator (TEG) with Cu contacts is improved by spin-on-doping (SOD). The Si NWAs used in this work are fabricated via metal assisted chemical etching (MACE) of 0.01-0.02 ? cm resistivity n- and p-type bulk, converting ˜4% of the bulk thickness into NWs. The MACE process is adapted to ensure crystalline NWs. Current-voltage and Seebeck voltage-temperature measurements show that while SOD mainly influences the contact resistance in bulk, it influences both contact resistance and power factor in NWA-bulk based TEGs. According to our experiments, using Si NWAs in combination with SOD increases the output power by an order of 3 under the same heating power due to an increased power factor, decreased thermal conductivity of the NWA and reduced Si-Cu contact resistance.

Xu, B.; Fobelets, K.

2014-06-01

313

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

314

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

315

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

316

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

317

Nanoengineered Materials for Thermoelectric Energy Conversion  

NASA Astrophysics Data System (ADS)

In this chapter we review recent advances in nanoengineered materials for thermoelectric energy conversion. We start by a brief overview of the fundamental interactions between heat and electricity, i.e., thermoelectric effects. A key requirement to improve the energy conversion efficiency is to increase the Seebeck coefficient (S) and the electrical conductivity (? ), while reducing the thermal conductivity (?). Nanostructures make it possible to modify the fundamental trade-offs between the bulk material properties through the changes in the density of states and interface effects on the electron and phonon transport. We will review recent experimental and theoretical results on superlattice and quantum dot thermoelectrics, nanowires, thin-film microrefrigerators, and solid-state thermionic power generation devices. In the latter case, the latest experimental results for semimetal rare-earth nanoparticles in a III-V semiconductor matrix as well as nitride metal/semiconductor multilayers will be discussed. We will briefly describe recent developments in nonlinear thermoelectrics, as well as electrically pumped optical refrigeration and graded thermoelectric materials. It is important to note that, while the material thermoelectric figure of merit (Z = S2? /? ) is a key parameter to optimize, one has to consider the whole system in an energy conversion application, and system optimization sometimes places other constraints on the materials.We will also review challenges in the experimental characterization of thin film thermoelectric materials. Finally, we will assess the potential of some of the more exotic techniques such as thermotunneling and bipolar thermoelectric effects.

Shakouri, Ali; Zebarjadi, Mona

318

Drought Vulnerability of Thermoelectric Generation using Texas as a Case Study  

NASA Astrophysics Data System (ADS)

Increasing extent, frequency, and intensity of droughts raises concerns about the vulnerability of thermoelectricity generation to water-shortages. In this study we evaluated the impact of the 2011 flash drought in Texas on electricity demand and water supply for power plants. The impacts of the drought were greater in sub-humid east Texas than in semiarid west Texas because most power plants are pre-adapted to low water availability in west Texas. This comparison between sub-humid and semiarid regions in Texas serves as a proxy for climatic differences between the eastern and western US. High temperatures with ?100 days of triple digit temperatures raised annual electricity demands/generation by 6% and peak demands in August by 4% relative to 2010. The corresponding water demands/consumption for 2011 for thermoelectric generation was increased by ~10% relative to 2010. While electricity demand only increased slightly during the drought, water supply decreased markedly with statewide reservoir storage at record lows (58% of capacity). Reductions in reservoir storage would suggest that power plants should be vulnerable to water shortages; however, data show that power plants subjected to water shortages were flexible enough to adapt by switching to less water-intensive technologies. Some power plants switched from once-through cooling to cooling towers with more than an order of magnitude reduction in water withdrawals whereas others switched from steam turbines to combustion turbines (no cooling water requirements) when both were available. Recent increases in natural gas production by an order of magnitude and use in combined cycle plants enhances the robustness of the power-plant fleet to drought by reducing water consumption (~1/3rd of that for steam turbines), allowing plants to operate with (combined cycle generator) or without (combustion turbine generator) water, and as base-load or peaking plants to complement increasing wind generation. Drought vulnerability of the power plant fleet can be further enhanced by reducing demand and/or increasing supplies of water (e.g. use of nontraditional water sources: municipal waste water or brackish water) and increasing supplies of electricity. Our ability to cope with projected increases in droughts would be greatly improved by joint management of water and electricity.

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

2013-12-01

319

High-throughput screening of thermoelectric oxides and power generation modules consisting of oxide unicouples  

NASA Astrophysics Data System (ADS)

A high-throughput screening technique has been developed and utilized in the discovery of a new n-type oxide possessing good thermoelectric properties. With this technique, 1000 samples can be prepared via a sol-gel method and their Seebeck coefficient (S) evaluated all within a day. For evaluation of S, a 'Seebeck tester' consisting of two pairs of thermocouples, a heater and a voltage meter, was developed. S values measured using the Seebeck tester more or less coincide with those using a conventional method. The validity of this technique was proven by Ca-Co-O and Na-Co-O systems. Screening ternary systems consisting of 3d transition metals using this technique showed LaNiO3 to possess the desired n-type properties. Electrical resistivity (?) of this oxide is favourably quite low; however, S is as low as -25 µV K-1 at high temperature. To enhance the thermoelectric properties of LaNiO3, high-throughput screening was employed to examine candidates from the metal ternary systems La1-xM1xNiO3 and LaNi1-xM2xO3. Bi substitution in the La1-xM1xNiO3 systems and Cu substitution in the LaNi1-xM2xO3 systems were found to be effective for improvement of S and ?, respectively. A thermoelectric unicouple composed of p-type Ca3Co4O9 (Co-349) and n-type LaNiO3 (Ni-113) bulks was constructed. Open-circuit voltage (Vo) of the unicouple reaches 100 mV at 1073 K on the hot side (TH) with a temperature difference (?T) of 500 K in air. Resistance of the unicouple (RI) is 26 m? at 1073 K in air and increases with increase in temperature. The Vo values are consistent with those calculated using S values for each oxide leg. Maximum power (Pmax), which was evaluated using the formula Pmax = V2o/4RI, is 94 mW at 1073 K (?T = 500 K) and increases with temperature. This value corresponds to a volume power density of 660 mW cm-3.

Funahashi, R.; Mikami, M.; Urata, S.; Kitawaki, M.; Kouuchi, T.; Mizuno, K.

2005-01-01

320

Comparison of maximum power point control methods for thermoelectric power generator  

Microsoft Academic Search

This paper describes the comparison of operating point control methods such as maximum power point tracking control (MPPT) and a constant voltage control applied to the thermoelectric devices. To experimentally evaluate the power control methods, a one-chip micro controller controlled DC-DC converter was inserted between the thermoelectric module and a load. The derived power from the module by constant voltage

H. Nagayoshi; T. Kajikawa; T. Sugiyama

2002-01-01

321

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

322

Nanostructured silicon for thermoelectric  

NASA Astrophysics Data System (ADS)

Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3? method will be shown.

Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

2011-05-01

323

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

324

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

NASA Astrophysics Data System (ADS)

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 a Seebeck coefficient in the range of 90-250 µV K-1 and an in-plane electrical resistivity in the range of 7-17 µ? m. The measurements also showed TE figures-of-merit, ZT, at room temperatures (T = 300 K) of 0.97 and 0.56, for thin films of Bi2Te3 and Sb2Te3, respectively (equivalent to a power factor, PF, of 4.87 mW K-2 m-1 and 2.81 mW K-2 m-1). The solid-state battery is based on thin films of: an anode of tin dioxide (SnO2), an electrolyte of lithium phosphorus oxynitride (LixPOyNz, known as LiPON) and a cathode of lithium cobaltate (LiCoO2, known as LiCO), which were deposited using the reactive RF (radio-frequency) sputtering. The deposition and characterization results of these thin-films layers are also reported in this paper.

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

2010-08-01

325

Two-Dimensional Thermal Resistance Analysis of a Waste Heat Recovery System with Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

In this study, it is shown that two-dimensional (2D) thermal resistance analysis is a rapid and simple method to predict the power generated from a waste heat recovery system with thermoelectric generators (TEGs). Performance prediction is an important part of system design, generally being simulated by numerical methods with high accuracy but long computational duration. Use of the presented analysis saves much time relative to such numerical methods. The simple 2D model of the waste heat recovery system comprises three parts: a recovery chamber, the TEGs, and a cooling system. A fin-structured duct serves as a heat recovery chamber, to which were attached the hot sides of two TEGs; the cold sides were attached to a cooling system. The TEG module and duct had the same width. In the 2D analysis, unknown temperatures are located at the centroid of each cell into which the system is divided. The relations among the unknown temperatures of the cells are based on the principle of energy conservation and the definition of thermal resistance. The temperatures of the waste hot gas at the inlet and of the ambient fluid are known. With these boundary conditions, the unknown temperatures in the system become solvable, and the power generated by the TEGs can be predicted. Meanwhile, a three-dimensional (3D) model of the system was simulated in FloTHERM 9.2. The 3D numerical solution matched the solution of the 2D analysis within 10%.

Huang, Gia-Yeh; Yao, Da-Jeng

2013-07-01

326

Power Generation Characteristics of Mg2Si Uni-Leg Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

Mg2Si thermoelectric (TE) elements were fabricated by a plasma-activated sintering method using a commercial polycrystalline n-type Mg2Si source produced by the Union Material Co., Ltd. This material typically has a ZT value of ˜0.6. A monobloc plasma-activated sintering technique was used to form Ni electrodes on the TE elements. The dimensions of a single element were 4.0 mm × 4.0 mm × 10 mm, and these were used to construct a TE module comprising nine elements connected in series. To reduce the electrical and thermal contact resistance of the module, each part of the module, i.e., the elements, terminals, and insulating plates, was joined using a Ag-based brazing alloy. In addition, to maintain the temperature difference between the top and bottom of the module, a thermal insulation board was installed in it. The observed values of open-circuit voltage ( V OC) and output power ( P) of a uni-leg structure module were 594 mV and 543 mW, respectively, at a maximum ? T = 500 K.

Nemoto, T.; Iida, T.; Sato, J.; Sakamoto, T.; Nakajima, T.; Takanashi, Y.

2012-06-01

327

Optimized thermoelectrics for energy harvesting applications  

Microsoft Academic Search

Bismuth telluride thermoelectric (TE) technology is well established in many small scale cooling applications including picnic boxes, auto seats, telecommunications lasers, military smart munitions and satellite applications. Applications using thermoelectric generators (TEGs) operating in reverse, for generating power from small ambient temperature differences are much less mature and not as well understood. Traditional bulk thermoelectric devices and thin film thermoelectric

Jim Bierschenk

2008-01-01

328

Synthesis of Nanocomposites with Improved Thermoelectric Properties  

Microsoft Academic Search

Bulk thermoelectric materials are of interest for commercial application in both power generation and Peltier refrigeration.\\u000a Various synthesis approaches have been developed by our group for high performance bulk thermoelectric materials, such as\\u000a solvo- or hydrothermal synthesis for nanopowders, hot-pressing, and spark plasma sintering for nanostructured bulk materials,\\u000a and rapid solidification for metal silicides. In this article we report some

X. B. Zhao; S. H. Yang; Y. Q. Cao; J. L. Mi; Q. Zhang; T. J. Zhu

2009-01-01

329

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

330

Evaluation of Power Conditioning Architectures for Energy Production Enhancement in Thermoelectric Generator Systems  

NASA Astrophysics Data System (ADS)

A large-scale thermoelectric generator (TEG) system has an unbalanced temperature distribution among the TEG modules, which leads to power mismatch among the modules and decreases the power output of the TEG system. To maximize the power output and minimize the power conversion loss, a centralized-distributed hybrid power conditioning architecture is presented, analyzed, and evaluated for a TEG system. The novel architecture is a combination of a conventional centralized architecture and a fully distributed architecture. By using the proposed architecture, most of the harvested power is processed by the centralized stage while only the mismatched power among the TEG modules is processed by the distributed stages. As a result, accurate and distributed maximum-power-point tracking (MPPT) for each TEG module and single-stage power conversion between the modules and load can be achieved. It offers the benefit of implementing high MPPT efficiency and high conversion efficiency simultaneously. A 50-W TEG system composed of two TEG modules is built and tested. Experimental results show that the proposed hybrid power conditioning architecture generates up to 5% more energy for a temperature difference between the two modules of only 10°C.

Wu, Hongfei; Sun, Kai; Chen, Min; Xing, Yan

2014-06-01

331

Integration of Thermoelectric Generators and Wood Stove to Produce Heat, Hot Water, and Electrical Power  

NASA Astrophysics Data System (ADS)

Traditional fire stoves are characterized by low efficiency. In this experimental study, the combustion chamber of the stove is augmented by two devices. An electric fan can increase the air-to-fuel ratio in order to increase the system's efficiency and decrease air pollution by providing complete combustion of wood. In addition, thermoelectric generators (TEGs) produce power that can be used to satisfy all basic needs. In this study, a water-based cooling system is designed to increase the efficiency of the TEGs and also produce hot water for residential use. Through a range of tests, an average of 7.9 W was achieved by a commercial TEG with substrate area of 56 mm × 56 mm, which can produce 14.7 W output power at the maximum matched load. The total power generated by the stove is 166 W. Also, in this study a reasonable ratio of fuel to time is described for residential use. The presented prototype is designed to fulfill the basic needs of domestic electricity, hot water, and essential heat for warming the room and cooking.

Goudarzi, A. M.; Mazandarani, P.; Panahi, R.; Behsaz, H.; Rezania, A.; Rosendahl, L. A.

2013-07-01

332

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

333

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

Microsoft Academic Search

One of the most obvious early market applications for thermoelectric generators (TEG) is decentralized micro combined heat\\u000a and power (CHP) installations of 0.5 kWe to 5 kWe based on fuel cell technology. Through the use of TEG technology for waste\\u000a heat recovery it is possible to increase the electricity production in micro-CHP systems by more than 15%, corresponding to\\u000a system electrical efficiency

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

2011-01-01

334

Fabrication and power generation characteristics of p-NaCo2O4\\/n-ZnO oxide thermoelectric modules  

Microsoft Academic Search

A prototype of thermoelectric module using oxide materials has been successfully fabricated, and the power generation characteristics have been examined in the high temperature region around 773 K (500 degC). Twelve couples of sintered p-NaCo2O4 and n-ZnO materials were connected via silver conducting strips with a planer arrangement jointed by using a diffusion welding technique under 16 MPa at 1023

T. Souma; M. Ohtaki; M. Shigeno; Y. Ohba; N. Nakamura; T. Shimozaki

2006-01-01

335

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

336

Study of Complete Thermoelectric Generator Behavior Including Water-to-Ambient Heat Dissipation on the Cold Side  

NASA Astrophysics Data System (ADS)

Reduction of the thermal resistances of the heat exchangers of a thermoelectric generation (TEG) system leads to a significant increase in TEG efficiency. For the cold side of a thermoelectric module (TEM), a wide range of heat exchangers have been studied, from simple finned dissipators to more complex water (water-glycol) heat exchangers. As the Nusselt number is much higher in water heat exchangers than in conventional air finned dissipators, the convective thermal resistances are better. However, to conclude which heat exchanger leads to higher efficiencies, it is necessary to include the whole system involved in the heat dissipation, i.e., the TEM-to-water heat exchanger, the water-to-ambient heat exchanger, as well as the required pumps and fans. This paper presents a dynamic computational model able to simulate the complete behavior of a TEG, including both heat exchangers. The model uses the heat transfer and hydraulic equations to compute the TEM-to-water and water-to-ambient thermal resistances, along with the resistance of the hot-side heat exchanger at different operating conditions. Likewise, the model includes all the thermoelectric effects with temperature-dependent properties. The model calculates the net power generation for different configurations, providing a methodology to design and optimize the heat exchange in order to maximize the net power generation for a wide variety of TEGs.

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

2014-06-01

337

Thermal Effect of Ceramic Substrate on Heat Distribution in Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

In thermoelectric generators (TEG), poor system design and load matching, which make the system less efficient, have been limiting factors in achieving high conversion efficiency. In this work, to consider the effect of the inlet plenum arrangement and the laminar coolant flow temperature variation in the heat sink, a parallel microchannel heat sink is applied to a real TEG. The focus of this study is a discussion of the temperature difference variation between the cold/hot sides of the TEG legs versus the variation of the thermal conductivity of the ceramic substrate and the thickness of the substrate on the hot side. While the imposed heat flux on the TEG is homogeneously constant, different pressure drops are applied along the microchannel heat sink. The three-dimensional governing equations for the fluid flow and heat transfer are solved using the finite-volume method. The results show that the temperature difference is affected remarkably by the pressure drops in the heat sink, the thermal conductivity of the ceramic substrate, and the thickness of the substrate on the hot side.

Rezania, A.; Rosendahl, L. A.

2012-06-01

338

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

339

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

340

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

PubMed

Energy conversion efficiency at maximum output power, which embodies the essential characteristics of heat engines, is the main focus of the present work. The so-called Curzon and Ahlborn efficiency ?(CA) is commonly believed to be an absolute reference for real heat engines; however, a different but general expression for the case of stochastic heat engines, ?(SS), was recently found and then extended to low-dissipation engines. The discrepancy between ?(CA) and ?(SS) is here analyzed considering different irreversibility sources of heat engines, of both internal and external types. To this end, we choose a thermoelectric generator operating in the strong-coupling regime as a physical system to qualitatively and quantitatively study the impact of the nature of irreversibility on the efficiency at maximum output power. In the limit of pure external dissipation, we obtain ?(CA), while ?(SS) corresponds to the case of pure internal dissipation. A continuous transition between from one extreme to the other, which may be operated by tuning the different sources of irreversibility, also is evidenced. PMID:22587047

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

2012-03-01

341

Computational modeling of Radioisotope Thermoelectric Generators (RTG) for interplanetary and deep space travel  

NASA Astrophysics Data System (ADS)

This research project is part of Narsis Nejat Master of Science thesis project that it is done at Shiraz University. The goals of this research are to make a computer model to evaluate the thermal power, electrical power, amount of emitted/absorbed dose, and amount of emitted/absorbed dose rate for static Radioisotope Thermoelectric Generators (RTG)s that is include a comprehensive study of the types of RTG systems and in particular RTG’s fuel resulting from both natural and artificial isotopes, calculation of the permissible dose radioisotope selected from the above, and conceptual design modeling and comparison between several NASA made RTGs with the project computer model pointing out the strong and weakness points for using this model in nuclear industries for simulation. The heat is being converted to electricity by two major methods in RTGs: static conversion and dynamic conversion. The model that is created for this project is for RTGs that heat is being converted to electricity statically. The model approximates good results as being compared with SNAP-3, SNAP-19, MHW, and GPHS RTGs in terms of electrical power, efficiency, specific power, and types of the mission and amount of fuel mass that is required to accomplish the mission.

Nejat, Cyrus; Nejat, Narsis; Nejat, Najmeh

2014-06-01

342

Thermoelectric generating system attached to a carburizing furnace at Komatsu Ltd., Awazu Plant  

NASA Astrophysics Data System (ADS)

At the end of October 2009, KELK Ltd. started a field test of the thermoelectric generation system at a carburizing furnace of Komatsu Ltd., Awazu Plant. Residual carburizing gas based on CO, H2 and N2 is burned resulting that 20-30 kW range of flame constantly heats up the hot side of TEG. A single unit of TEG consists of 16 of the Bi-Te thermo-modules, each of which has a size of 50 × 50 × 4.2 mm3 and can generate 24W under the circumstance of 280 °C and 30 °C of hot side and cold side temperature, respectively [1]. 16 modules are separated into 4 groups and they are connected electrically depending on design concept, namely in case of focusing on reliability, parallel connection are used and in case of on simplicity and high-voltage transmission, series connection is preferably employed. The module is being life-time tested at various conditions. For instance, 10,000 of heat cycling under the hot side temperature between 250 and 50 °C with a constant cold side temperature at 30 °C gives within a few percent degrade. Both buck-and booster-type DC/DC converters controlled by one chip computer were set up and Maximum Power Point Tracking (MPPT) was well facilitated to search for the maximum output power depending on the hot and cold temperature. The electric output power from the 16 modules is summed up to charge 4 lead storage batteries (12V-65Ah) and then through DC/AC inverters electricity goes to LED light tubes inside the factory. 214 W can be generated and 180 W is delivered to the batteries.

Kaibe, H.; Makino, K.; Kajihara, T.; Fujimoto, S.; Hachiuma, H.

2012-06-01

343

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

344

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

345

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.

2014-01-01

346

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

347

Recent advances on thermoelectric materials  

Microsoft Academic Search

By converting waste heat into electricity through the thermoelectric power of solids without producing greenhouse gas emissions,\\u000a thermoelectric generators could be an important part of the solution to today’s energy challenge. There has been a resurgence\\u000a in the search for new materials for advanced thermoelectric energy conversion applications. In this paper, we will review\\u000a recent efforts on improving thermoelectric efficiency.

Jin-Cheng Zheng

2008-01-01

348

Correlated thermoelectrics  

NASA Astrophysics Data System (ADS)

In the first part of these lecture notes we introduce the phenomenological equations for describing the heat and charge transport in thermoelectric samples. We discuss the solution obtained for various boundary conditions that are appropriate for the homogeneous and inhomogeneous thermoelectrics. In the second part we develop the formalism for a linear-response many-body description of the transport properties of correlated electrons. By properly determining the local heat-current operator we show that the Jonson-Mahan theorem applies to the Hamiltonians that are commonly used for the intermetallic compounds with Cerium, Europium and Ytterbium ions, so the various thermal-transport coefficient integrands are related by powers of frequency. We illustrate how to use this formalism by calculating the thermoelectric properties of the periodic Anderson model and, then, show that these results explain the experimental data on heavy fermions and valence fluctuators. Finally, we calculate the thermoelectric properties of the Falicov-Kimball model and use the results to explain the anomalous features of the intermetallic compounds in which one observes the valence-change transition.

Zlati?, V.

2008-05-01

349

Thermoelectrical Energy Recovery from the Exhaust of a Light Truck.  

National Technical Information Service (NTIS)

A team formed by Clarkson University is engaged in a project to design, build, model, test, and develop a plan to commercialize a thermoelectric generator (TEG) system for recovering energy from the exhaust of light trucks and passenger cars.

M. A. Karri E. F. Thacher B. T. Helenbrook M. S. Compeau

2003-01-01

350

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

351

A New High Efficiency Segmented Thermoelectric Unicouple  

NASA Technical Reports Server (NTRS)

To achieve high thermal-to-electric energy conversion efficiency, it is desirable 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 is suitable for use over a very wide range of temperatures (approx. 300 - 1000 K). It is therefore necessary to use different materials in each temperature range where they possess optimum performance. This can be achieved in two ways: 1) multistage thermoelectric generators where each stage operates over a fixed temperature difference and is electrically insulated but thermally in contact with the other stages and 2) segmented generators where the p- and n-legs are formed of different segments joined in series. The concept of integrating new thermoelectric materials developed at the Jet Propulsion Laboratory (JPL) into a segmented thermoelectric generator has been presented in detail in earlier publications . This new generator is expected to operate over a 300-973 K temperature difference and will use novel segmented legs based on a combination of state-of-the-art thermoelectric materials and novel p-type Zn4Sb3, p-type CeFe4Sb12-based alloys and n-type CoSb3-based alloys. An increase in the conversion efficiency of about 60% is expected compared to conventional Bi2Te3- and PbTe-based generators. We present in this paper the latest experimental results from the bonding studies between the different segments of the p-legs, n-legs, and p-leg to n-leg interconnect. Evaluation of the bond quality was done by measuring the contact resistance across the joints as well as by detailed microstructure investigations to reveal any potential interdiffusion. Among the materials investigated as inter-layers between the different segments of the legs, Pd-Ag joining alloys have been found to provide mechanically stable and low electrical resistance bonds.

Caillat, T.; Fleurial, J.-P.; Snyder, G. J.; Zoltan, A.; Zoltan, D.; Borshchevsky, A.

2000-01-01

352

Performance analysis and validation of thermoelectric energy harvesters  

NASA Astrophysics Data System (ADS)

An analytical electrothermal model is developed and validated using experimental measurements. This model is based on known equations of the thermoelectric theory by accounting for the influence of the temperature on the internal properties of thermoelectric generators. General expressions for the internal properties of thermoelectric generators for different ranges of temperatures are determined. The validation of the model shows that representing the variations of the electrical internal resistance and Seebeck coefficient by linear and quadratic analytic expressions, respectively, as a function of the hot-side temperature is satisfactory. The results show the importance of including the effects of the temperature on the properties of the thermoelectric generator. This is especially true because the maximum generated power is realized when the load resistance is set equal to the internal resistance. The model is used to determine characteristic curves for optimal performance of these generators under different operating hot-side temperatures and temperature differences.

Abdelkefi, A.; Alothman, A.; Hajj, M. R.

2013-09-01

353

Mathematical simulation of thermoelectric power generation with the multi-panels  

Microsoft Academic Search

Electric power was estimated in case of the large-scale flat thermoelectric panels exposed to two thermal fluids. The output powers of the proposed 15 systems were analytically deduced from heat transfer theory, and written by non-dimensional functions to reflect the characteristics of system design. The maximum output was the largest in the ideal isothermal systems. In the other realistic systems,

Ryosuke O. Suzuki; Daisuke Tanaka

2003-01-01

354

Mathematic simulation on thermoelectric power generation with cylindrical multi-tubes  

Microsoft Academic Search

Analytical expression of electric power was deduced in case of the large-scale cylindrical thermoelectric tubes exposed to two thermal fluids. The output powers of the proposed six geometrical arrangements were mathematically solved from heat transfer theory, and compared with the flat panel systems. The maximum output was the largest in the ideally cooled systems. In the other realistic systems, it

Ryosuke O. Suzuki; Daisuke Tanaka

2003-01-01

355

Next-Generation Thermo-Electric Digital Time Delay Device. Replacement for Current Pyrotechnic Delay Cartridges.  

National Technical Information Service (NTIS)

What is the digital time delay or DTD. (1) A new thermo-electric device which can directly replace many existing pyrotechnic time delay cartridges. (2) Requires no external source of power and does not contain batteries. (3) Provides order of magnitude im...

D. Harrington K. Hicks

2005-01-01

356

Design and development of a thermoelectric cogeneration device integrated in autonomous gas heaters  

NASA Astrophysics Data System (ADS)

An autonomous heat-radiating gas heater for commercial outdoor environments has been selected as a test case for implementing cogeneration in autonomous gas heaters and stoves, permitting its installation and operation without the need of a connection to the electrical network. A thermoelectric generator (TEG) was selected for this purpose[1], designed for converting an amount of the produced heat into electrical power for auxiliary (ventilation, battery recharge) or ancillary functions (high efficiency LED illumination). The design approach, the layout and structure of the TEG are discussed, as well as the constraints for its integration in the existing gas heater. Design features and main components are examined: hot side heat collector for capturing heat from the flame; thermoelectric module (TEGM) technology and model selection; natural convection heat radiator at cold side; analysis and optimization of the thermal chain; TEG's assembly and its design as a whole. A prototype has been built and tested, its functional behavior has been modeled through multi-physics numerical simulation[2] to allow for further optimization and extrapolation of the results towards larger and/or more complex designs. A patent application has been issued jointly by the authors, covering the design hereinafter described.

Codecasa, Matteo P.; Fanciulli, Carlo; Gaddi, Roberto; Passaretti, Francesca

2012-06-01

357

THERMOELECTRIC POWER HARVESTING SYSTEMS  

EPA Science Inventory

Energy production based on fossil fuels negatively impacts the environment and is not sustainable. Recent advances in the area of nanotechnology have lead to improved performance of direct energy conversion devices such as thermoelectric generators. However, these efforts have...

358

Recent Advances in the Development of Skutterudites as Efficient Power Conversion Thermoelectrics  

NASA Astrophysics Data System (ADS)

Ever increasing demand for fossil fuels contrasting with their gradually depleted reserves, coupled with the fact that, on average, 60% of energy in industrial processes turns into heat dictate a new energy strategy relying more on renewable energy sources and recovery of waste industrial heat. Thermoelectric (TE) conversion can play a meaningful role in this new paradigm provided more efficient TE materials can be identified and developed. How efficiently a material converts heat into electricity (or, conversely, electricity into a heat pump) by purely solid state means is judged by the thermoelectric figure of merit defined as ZT = (S^2?T)/?, where S, ?, ?, and T stand for the Seebeck coefficient, electrical conductivity, thermal conductivity, and the absolute temperature, respectively. During the past dozen or so years, the worldwide search has brought to light several novel and prospective TE materials. Among them, perhaps the most promising for mid-temperature (500K-900K) energy conversion are cubic, open structure materials called skutterudites. In this talk I describe their structure and relate it to transport properties that govern efficient TE conversion. Nanometer-scale inclusions in a bulk matrix have recently been vigorously explored as a means of enhancing scattering of heat-carrying phonons as well as attempting to enhance the Seebeck coefficient by carrier confinement. I discuss criteria the nanostructure should satisfy in order to improve the figure of merit and illustrate the concepts on skutterudite nanocomposite structures grown recently by highly non-equilibrium processes. Finally, I discuss virtues of skutterudites as power conversion thermoelectrics in the recovery of waste heat in automotive operations.

Uher, Ctirad

2011-04-01

359

Program for the development of a thermoelectric battery operated by a ²³⁸Pu source for pacemakers  

Microsoft Academic Search

The Italian firm SORIN has undertaken a program for the development of a ; radioisotope battery, fueled with²³⁸ Pu which could be used for powering a ; cardiac pacemaker with a lifetime of about ten years. The design criteria for ; the battery, based on thermoelectric conversion, are described. The results ; obtained on the way to develop a model

B. Chinaglia; F. Vercellotti

1972-01-01

360

Thermoelectric generation and related properties of conventional type module based on SiGe alloy  

Microsoft Academic Search

A conventional type thermoelectric module based on Si2Ge has been made for power use. The module consists of 10 pairs of p- and n-type Si2Ge elements in which B and P were doped (~1020 cm-3) respectively. The elements electrically connected in series using Mo electrodes are sandwiched between AIN plates. Each plate is 20 mm×44 mm in area, and the

Masakazu KOBAYASHI; Keiko IKOMA; Kenji FURUYA; Kazuhiko SHINOHARA; Hiroshi TAKAO; Makoto MIYOSHI; Yuichiro IMANISHI; Tetsuo WATANABE

1996-01-01

361

Fabrication of a thermoelectric generator on a polymer-coated substrate via laser-induced forward transfer of chalcogenide thin films  

NASA Astrophysics Data System (ADS)

We have demonstrated the fabrication of a thermoelectric energy harvesting device via laser-induced forward transfer of intact solid thin films. Thermoelectric chalcogenide materials, namely bismuth telluride (Bi2Te3), bismuth selenide (Bi2Se3) and bismuth antimony telluride (Bi0.5Sb1.5Te3), were sequentially printed using a nanosecond excimer laser onto an elastomeric polydimethylsiloxane-coated glass substrate to form thermocouples connected in series creating a thermoelectric generator. The resulting generator Seebeck coefficient and series resistance per leg pair were measured to be 0.17 mV K-1 and 10 k? respectively. It was shown that laser-induced forward transfer allows device fabrication from inorganic semiconductor compounds on inexpensive elastic polymer substrates and demonstrates the ability to print materials with pre-defined thermoelectric properties. This allows the rapid manufacturing of a complete thermoelectric device on mm2-areas with ?m-scale precision, without the need of further lithographic steps.

Feinaeugle, M.; Sones, C. L.; Koukharenko, E.; Eason, R. W.

2013-11-01

362

Thin Films for Thermoelectric Applications  

NASA Astrophysics Data System (ADS)

The introduction of nanotechnology opened new horizons previously unattainable by thermoelectric devices. The nano-scale phenomena began to be exploited through techniques of thin-film depositions to increase the efficiency of thermoelectric films. This chapter reviews the fundamentals of the phenomenon of thermoelectricity and its evolution since it was discovered in 1822. This chapter also reviews the thermoelectric devices, the macro to nano devices, describing the most used techniques of physical vapor depositions to deposit thermoelectric thin-films. A custom made deposition chamber for depositing thermoelectric thin films by the thermal co-evaporation technique, where construction issues and specifications are discussed, is then presented. All the steps for obtaining a thermoelectric generator in flexible substrate with the custom deposition chamber (to incorporate in thermoelectric microsystems) are described. The aim of thermoelectric microsystem relays is to introduce an energy harvesting application to power wireless sensor networks (WSN) or biomedical devices. The scanning probe measuring system for characterization of the thermoelectric thin films are also described in this chapter. Finally, a few of the prototypes of thermoelectric thin films (made of bismuth and antimony tellurides, {Bi}2{Te}3, and {Sb}2{Te}3, respectively) obtained by co-evaporation (using the custom made deposition chamber) and characterized for quality assessment are dealt with. All the issues involved in the co-evaporation and characterization are objects of analysis in this chapter.

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

363

Thermoelectric Outer Planets Spacecraft (TOPS)  

NASA Technical Reports Server (NTRS)

The research and advanced development work is reported on a ballistic-mode, outer planet spacecraft using radioisotope thermoelectric generator (RTG) power. The Thermoelectric Outer Planet Spacecraft (TOPS) project was established to provide the advanced systems technology that would allow the realistic estimates of performance, cost, reliability, and scheduling that are required for an actual flight mission. A system design of the complete RTG-powered outer planet spacecraft was made; major technical innovations of certain hardware elements were designed, developed, and tested; and reliability and quality assurance concepts were developed for long-life requirements. At the conclusion of its active phase, the TOPS Project reached its principal objectives: a development and experience base was established for project definition, and for estimating cost, performance, and reliability; an understanding of system and subsystem capabilities for successful outer planets missions was achieved. The system design answered long-life requirements with massive redundancy, controlled by on-board analysis of spacecraft performance data.

1973-01-01

364

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

365

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

366

High performance n-type (Bi,Sb)2(Te,Se)3 for low temperature thermoelectric generator  

NASA Astrophysics Data System (ADS)

Starting with elemental chunks of bismuth, antimony, tellurium and selenium, densified bulk materials (Bi0.95Sb0.05)2(Te1-xSex)3 (x = 0.10, 0.13, 0.15 and 0.17) were prepared by melt spinning subsequently combined with a spark plasma sintering process. The prepared bulk materials display fine grain size and numerous layered structures with a size of 10-100 nm; moreover, details of the composition difference and phase difference cannot be observed. Measurements of electrical conductivity, Seebeck coefficient and thermal conductivity have been performed in the temperature range 300-500 K, and it is found that the thermoelectric properties are significantly affected by the content of selenium. All the prepared samples show higher ratios of electrical conductivity and total thermal conductivity compared with state-of-the-art commercial zone melted materials, mainly a large reduction in lattice thermal conductivity, which is more beneficial to the concept of 'electron crystal phonon glass'. Subsequently, the resulting thermoelectric figure of merit ZT value reaches a maximum of 1.0 at 460 K for the n-type (Bi0.95Sb0.05)2(Te0.85Se0.15)3 bulk material. Compared with traditional zone melted materials, the peak ZTs move towards a higher temperature and this study demonstrates the possibility of preparing materials with high performance, which can be applied for low temperature power generation or multi-stage devices.

Wang, Shanyu; Xie, Wenjie; Li, Han; Tang, Xinfeng

2010-08-01

367

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

368

Tailoring effective thermoelectric tensors and high-density power generation in a tubular Bi0.5Sb1.5Te3/Ni composite with cylindrical anisotropy  

NASA Astrophysics Data System (ADS)

Transverse thermoelectric responses in heterogeneous composites made of periodically laminated Bi0.5Sb1.5Te3/Ni in a tubular shape were investigated. Numerical calculations quantitatively clarify the relationship between geometrical parameters and effective thermoelectric tensors. In the present tubular heterogeneous composites, the temperature gradient across the radial direction yields a transverse voltage along the axial direction due to the unnatural cylindrical anisotropy. The tubular configuration allows for direct and efficient heat transfer from fluid heat sources. A high-density power generation of 417 W m-2 was achieved under the small temperature difference of 83 K.

Kanno, Tsutomu; Sakai, Akihiro; Takahashi, Kouhei; Omote, Atsushi; Adachi, Hideaki; Yamada, Yuka

2012-07-01

369

A 1 kWel thermoelectric stack for geothermal power generation - Modeling and geometrical optimization  

NASA Astrophysics Data System (ADS)

A thermoelectric stack composed of arrays of Bi-Te alloy thermoelectric converter (TEC) modules is considered for geothermal heat conversion. The TEC modules consist of Al2O3 plates with surface 30×30 mm2 and 127 p-type (Bi0.2Sb0.8)2Te3 and n-type Bi2(Te0.96Se0.04)3 thermoelement pairs, each having a cross-section of 1.05×1.05 mm2, and with a figure-of-merit of 1 and a heat-to-electricity conversion efficiency of ~5%. A heat transfer model is formulated to couple conduction in the thermoelements with convection between the Al2O3 plates and the water flow in counter-flow channel configuration. The calculated open-circuit voltages are compared to those resulting from the mean temperature differences across the TEC modules computed by CFD. The investigated parameters are: hot water inlet and outlet temperatures (373 - 413 K and 323 - 363 K, respectively), stack length (300 - 1500 mm), thermoelement length (1 - 4 mm) and hot channel heights (0.2 - 2 mm). The heat transfer model is then applied to optimize a 1 kWel stack with hot water inlet at 393 K and outlet at 353 K for either maximum heat-to-electricity conversion efficiency of 2.9% or minimum size of 0.0044 m3.

Suter, C.; Jovanovic, Z.; Steinfeld, A.

2012-06-01

370

Thermoelectric Materials  

NASA Astrophysics Data System (ADS)

Mg2(Si,Sn) compounds are promising candidate low-cost, lightweight, nontoxic thermoelectric materials made from abundant elements and are suited for power generation applications in the intermediate temperature range of 600 K to 800 K. Knowledge on the transport and mechanical properties of Mg2(Si,Sn) compounds is essential to the design of Mg2(Si,Sn)-based thermoelectric devices. In this work, such materials were synthesized using the molten-salt sealing method and were powder processed, followed by pulsed electric sintering densification. A set of Mg2.08Si0.4- x Sn0.6Sb x (0 ? x ? 0.072) compounds were investigated, and a peak ZT of 1.50 was obtained at 716 K in Mg2.08Si0.364Sn0.6Sb0.036. The high ZT is attributed to a high electrical conductivity in these samples, possibly caused by a magnesium deficiency in the final product. The mechanical response of the material to stresses is a function of the elastic moduli. The temperature-dependent Young's modulus, shear modulus, bulk modulus, Poisson's ratio, acoustic wave speeds, and acoustic Debye temperature of the undoped Mg2(Si,Sn) compounds were measured using resonant ultrasound spectroscopy from 295 K to 603 K. In addition, the hardness and fracture toughness were measured at room temperature.

Gao, Peng; Berkun, Isil; Schmidt, Robert D.; Luzenski, Matthew F.; Lu, Xu; Bordon Sarac, Patricia; Case, Eldon D.; Hogan, Timothy P.

2014-06-01

371

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

2014-05-01

372

Maximum Power Point Tracking Controller for Thermoelectric Generators with Peak Gain Control of Boost DC-DC Converters  

NASA Astrophysics Data System (ADS)

An analog maximum power point tracking (MPPT) circuit for a thermoelectric generator (TEG) is proposed. We show that the peak point of the voltage conversion gain of a boost DC-DC converter with an input voltage source having an internal resistor is the maximum power point of the TEG. The key characteristic of the proposed MPPT controller is that the duty ratio of the input clock pulse to the boost DC-DC converter shifts toward the maximum power point of the TEG by seeking the peak gain point of the boost DC-DC converters. The proposed MPPT technique provides a simple and useful analog MPPT solution, without employing digital microcontroller units.

Park, Jungyong; Kim, Shiho

2012-06-01

373

Sublimation behavior of silicon nitride /Si3N4/ coated silicon germanium /SiGe/ unicouples. [for Radioisotope Thermoelectric Generators  

NASA Technical Reports Server (NTRS)

For the Multi-Hundred Watt (MHW) Radioisotope Thermoelectric Generator (RTG), the silicon germanium unicouples are coated with silicon nitride to minimize degradation mechanisms which are directly attributable to material sublimation effects. A program is under way to determine the effective vapor suppression of this coating as a function of temperature and gas environment. The results of weight loss experiments, using Si3N4 coated hot shoes (SiMo), operating over a temperature range from 900 C to 1200 C, are analyzed and discussed. These experiments were conducted both in high vacuum and at different pressures of carbon monoxide (CO) to determine its effect on the coating. Although the results show a favorable vapor suppression at all operating temperatures, the pressure of the CO and the thickness of the coating have a decided effect on the useful lifetime of the coating.

Stapfer, G.; Truscello, V. C.

1975-01-01

374

Electron transport in erbium arsenide:indium gallium(aluminum)arsenide metal/semiconductor nanocomposites for thermoelectric power generation  

NASA Astrophysics Data System (ADS)

Electron transport in thin film ErAs:InGa(Al)As metal/semiconductor nanocomposite materials grown by molecular beam epitaxy is investigated experimentally and theoretically for efficient thermoelectric power generation. Thermoelectric properties such as the Seebeck coefficient, the electrical conductivity, and the thermal conductivity are measured for the various compositions of the material up to 840 K. A special sample preparation method is proposed to protect the thin films from damage and/or decomposition, and prevent the parasitic substrate conduction effect during the high temperature measurements. The sample preparation method includes surface passivation, high temperature metallization with a diffusion barrier, and the covalent oxide bonding technique for substrate removal. The experimental results for the nanocomposite materials are analyzed using the Boltzmann transport equation under the relaxation time approximation. The scattering characteristics of free electrons in the InGa(Al)As is defined by four major scattering mechanisms such as the polar optical phonon scattering, the ionized impurity scattering, the alloy scattering, and the acoustic phonon deformation potential scattering. Combining these scattering mechanisms, the electron transport model successfully fits the temperature-dependent thermoelectric properties of Si-doped InGaAlAs materials, and predicts the figure of merits at various doping levels in various Al compositions. The nanoparticle-electron interaction is modeled as a momentum scattering for free electrons caused by the electrostatic potential perturbation around nanoparticles and the band offset at the interface. The ErAs nanoparticles are assumed to be semi-metals that can donate electrons to the matrix, and positively charged after the charge transfer to build up the screened coulomb potential outside them. The nanoparticle scattering rate is calculated for this potential profile using the partial wave method, and used to analyze the enhancement of the Seebeck coefficient. Finally, the experimental results for the various compositions of the ErAs:InGa(Al)As nanocomposites are fit using the electron transport model and the nanoparticle scattering. It is shown that nanoparticle scattering can enhance the power factor via energy-dependent electron scattering in ErAs:InGaAs system. The figure of merit for the 0.6% ErAs:(InGaAs)0.8(InAlAs) 0.2 lattice matched to InP is measured to be 1.3 at 800 K, and the theory predicts that it can reach 1.9 at 1000 K.

Bahk, Je-Hyeong

375

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

376

Thermoelectric properties of silicon nanostructures  

Microsoft Academic Search

Semiconductor nanostructures are promising candidates for efficient thermoelectric energy conversion, with applications in solid-state refrigeration and power generation. The design of efficient semiconductor thermocouples requires a thorough understanding of both charge and heat transport; therefore, thermoelectricity in silicon-based nanostructures requires that both electronic and thermal transport be treated on an equal footing. In this paper, we present semiclassical simulation of

Zlatan Aksamija; Irena Knezevic

2010-01-01

377

Maximum Utilization of Thermoelectric Materials  

Microsoft Academic Search

This paper covers the derivation of the factors related to the most effective use of thermoelectric materials for cooling and power generation. It is shown theoretically and verified experimentally that device performance is maintained constant independent of the amount of thermoelectric material used. A practical limit in this weight reduction exists, and is shown to be dependent upon the quality

James P. Burgess; Neal P. Milligan

1964-01-01

378

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

379

Ecologically pure thermoelectric climatic systems  

Microsoft Academic Search

Ecologically pure thermoelectric climatic systems are designed for use as industrial, household, automobile and railway air conditioners. In this paper we present the characteristics of developed basic thermoelectric units (BTUs), that are used for assembling climatic systems of any power. One of the most prospective basic thermoelectric units has the following characteristics: dimensions-250×160×160 mm, flow of cooled air-4 m 3

A. Guliaev; A. Holopkin

1998-01-01

380

Solar thermolectric generator based on skutterudites  

NASA Astrophysics Data System (ADS)

A numerical simulation based on the optimal control theory was developed to assess the performances, dimensions and weight characteristics of skutterudite-based solar thermoelectric generators (STG) for satellite missions at distances close to the Sun. It is shown that the STG designs based on these advanced thermoelectric materials are potentially attractive for this type of application and could advantageously replace the standard power sources such as the solar (cells) panel or the radioisotope thermoelectric generators.

Scherrer, H.; Vikhor, L.; Lenoir, B.; Dauscher, A.; Poinas, P.

381

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

382

Modal Analysis and Study of the Vibration Characteristics of the Thermoelectric Modules of Vehicle Exhaust Power-Generation Systems  

NASA Astrophysics Data System (ADS)

Thermoelectric (TE) materials and modules are important components of vehicle exhaust power-generation systems. The road and the engine, the main sources of vibration of TE modules, have substantial effects on the vibration characteristics of TE modules. In this work, modal analysis and the vibration characteristics of TE modules were investigated in detail. On the basis of the TE modules and their service environment, simulations for modal analysis were performed by use of the finite-element method, and the natural frequencies and mode shapes of the TE modules were obtained. The numerical results were used to compare the natural frequencies of TE modules under different contact stiffness with the range of excitation frequencies of road and engine, in an attempt to prevent severe resonance. The effects on the vibration characteristics of geometric dimensions, service temperature, and thermal stress of the TE modules are also discussed in detail. The results reveal the vibration characteristics of the TE modules and provide theoretical guidance for structure optimization in the design of vehicle exhaust power-generation systems.

Chen, Gang; Mu, Yu; Zhai, Pengcheng; Yu, Rui; Li, Guodong; Zhang, Qingjie

2014-06-01

383

Thermoelectric cooler  

Microsoft Academic Search

This patent describes a thermoelectric cooler, comprising: a storage compartment for the storage of items therein, at least one, separate, detached coupling pad fabricated of thermoconductive material, means for attaching the coupling pad onto the storage compartment, a thermoelectric module secured to the pad with the cold face of the module against the pad; and means mounting a heat exchanger

Beitner

1986-01-01

384

Present state of R&D on thermoelectric technology in Japan  

Microsoft Academic Search

Thermoelectric technology, in particular, thermoelectric power generation technology, has been recognized as one of the major energy conservation technologies in Japan. Recent outstanding results on the thermoelectric performance for various kinds of thermoelectric materials such as layered Co-based oxides, filled skutterudites etc. show a good potential for achieving high ZT values. These results encouraged and accelerated R&D activities of thermoelectric

T. Kajikawa

2001-01-01

385

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

386

PEROVSKITE-TYPE THERMOELECTRIC OXIDES AND OXYNITRIDES  

Microsoft Academic Search

Direct and efficient thermoelectric conversion of solar or geothermal waste heat into electricity requires the development of p- and n-type thermoelectrics with similar materials properties. Perovskite-type transition metal- oxides and oxynitrides are investigated as potential candidates for thermoelectric devices operating at high temperatures as they can possess large positive as well as large negative thermopower depending on their composition. Cobaltates,

A. Weidenkaff; R. Robert; L. Bocher; P. Tomes; M. Trottmann; M. H. Aguirre

387

High-accuracy direct ZT and intrinsic properties measurement of thermoelectric couple devices  

NASA Astrophysics Data System (ADS)

Advances in thermoelectric materials in recent years have led to significant improvements in thermoelectric device performance and thus, give rise to many new potential applications. In order to optimize a thermoelectric device for specific applications and to accurately predict its performance ideally the material's figure of merit ZT as well as the individual intrinsic properties (Seebeck coefficient, electrical resistivity, and thermal conductivity) should be known with high accuracy. For that matter, we developed two experimental methods in which the first directly obtains the ZT and the second directly measures the individual intrinsic leg properties of the same p/n-type thermoelectric couple device. This has the advantage that all material properties are measured in the same sample direction after the thermoelectric legs have been mounted in the final device. Therefore, possible effects from crystal anisotropy and from the device fabrication process are accounted for. The Seebeck coefficients, electrical resistivities, and thermal conductivities are measured with differential methods to minimize measurement uncertainties to below 3%. The thermoelectric couple ZT is directly measured with a differential Harman method which is in excellent agreement with the calculated ZT from the individual leg properties. The errors in both the directly measured and calculated thermoelectric couple ZT are below 5% which is significantly lower than typical uncertainties using commercial methods. Thus, the developed technique is ideal for characterizing assembled couple devices and individual thermoelectric materials and enables accurate device optimization and performance predictions. We demonstrate the methods by measuring a p/n-type thermoelectric couple device assembled from commercial bulk thermoelectric Bi2Te3 elements in the temperature range of 30 °C-150 °C and discuss the performance of the couple thermoelectric generator in terms of its efficiency and materials' self-compatibility.

Kraemer, D.; Chen, G.

2014-04-01

388

High-accuracy direct ZT and intrinsic properties measurement of thermoelectric couple devices.  

PubMed

Advances in thermoelectric materials in recent years have led to significant improvements in thermoelectric device performance and thus, give rise to many new potential applications. In order to optimize a thermoelectric device for specific applications and to accurately predict its performance ideally the material's figure of merit ZT as well as the individual intrinsic properties (Seebeck coefficient, electrical resistivity, and thermal conductivity) should be known with high accuracy. For that matter, we developed two experimental methods in which the first directly obtains the ZT and the second directly measures the individual intrinsic leg properties of the same p/n-type thermoelectric couple device. This has the advantage that all material properties are measured in the same sample direction after the thermoelectric legs have been mounted in the final device. Therefore, possible effects from crystal anisotropy and from the device fabrication process are accounted for. The Seebeck coefficients, electrical resistivities, and thermal conductivities are measured with differential methods to minimize measurement uncertainties to below 3%. The thermoelectric couple ZT is directly measured with a differential Harman method which is in excellent agreement with the calculated ZT from the individual leg properties. The errors in both the directly measured and calculated thermoelectric couple ZT are below 5% which is significantly lower than typical uncertainties using commercial methods. Thus, the developed technique is ideal for characterizing assembled couple devices and individual thermoelectric materials and enables accurate device optimization and performance predictions. We demonstrate the methods by measuring a p/n-type thermoelectric couple device assembled from commercial bulk thermoelectric Bi2Te3 elements in the temperature range of 30?°C-150?°C and discuss the performance of the couple thermoelectric generator in terms of its efficiency and materials' self-compatibility. PMID:24784659

Kraemer, D; Chen, G

2014-04-01

389

Advanced Thermoelectric Materials for Efficient Waste Heat Recovery in Process Industries  

Microsoft Academic Search

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

Adam Polcyn; Moe Khaleel

2009-01-01

390

Local structure study of new thermoelectric materials  

NASA Astrophysics Data System (ADS)

The atomic pair distribution function (PDF) technique is used to study the local structure of new thermoelectric materials. The PDF is obtained via Fourier transformation of powder total scattering data including the important local structural information in the diffuse scattering intensities underneath, and in-between, the Bragg peaks. Having long been used to study liquids and amorphous materials, the PDF technique has been recently successfully applied to highly crystalline materials owing to the advances in modern X-ray and neutron sources and computing power. Devices based on the thermoelectric effect hold promise for solid-state cooling and power generation but developments in materials properties are required for widespread application. Recently, the importance of nanometer-scale structures has been recognized for improving the thermoelectric properties of materials. In this work we couple the power of the PDF method for giving nano-scale structural information with the need to characterize nanostructure in a number of promising novel thermoelectric materials. Promising Nanoclusters are found to exist in the PbTe based materials with unusual thermoelectric properties. For two series of material AgPb mSbTem+2 and (PbTe)1- x(PbS)x we verify the bulk nature of such nanoclusters and also determine the average chemical composition and nature of these nanoclusters. Traces of nanoclusters are also found in Ag 1-xSnSb1+xTe 3 series materials. This information is important in the effort to understand the relationship between the existence of nanoclusters and the exceptional thermoelectric properties.

Lin, He

391

An Introduction to System-Level, Steady-State and Transient Modeling and Optimization of High-Power-Density Thermoelectric Generator Devices Made of Segmented Thermoelectric Elements  

NASA Astrophysics Data System (ADS)

High-power-density, segmented, thermoelectric (TE) elements have been intimately integrated into heat exchangers, eliminating many of the loss mechanisms of conventional TE assemblies, including the ceramic electrical isolation layer. Numerical models comprising simultaneously solved, nonlinear, energy balance equations have been created to simulate these novel architectures. Both steady-state and transient models have been created in a MATLAB/Simulink environment. The models predict data from experiments in various configurations and applications over a broad range of temperature, flow, and current conditions for power produced, efficiency, and a variety of other important outputs. Using the validated models, devices and systems are optimized using advanced multiparameter optimization techniques. Devices optimized for particular steady-state operating conditions can then be dynamically simulated in a transient operating model. The transient model can simulate a variety of operating conditions including automotive and truck drive cycles.

Crane, D. T.

2011-05-01

392

New Composite Thermoelectric Materials for Macro-size Applications (APS Colloquium, 2008)  

ScienceCinema

A review will be given of several important recent advances in both thermoelectrics research and industrial thermoelectric applications, which have attracted much attention, increasing incentives for developing advanced materials appropriate for large-scale applications of thermoelectric devices. One promising strategy is the development of materials with a dense packing of random nanostructures as a route for the sacle-up of thermoelectrics applications. The concepts involved in designing composite materials containing nanostructures for thermoelectric applications will be discussed in general terms. Specific application is made to the Bi{sub 2}Te{sub 3} nanocomposite system for use in power generation. Also emphasized are the scientific advantages of the nanocomposite approach for the simultaneous increase in the power factor and decrease of the thermal conductivity, along with the practical advantages of having bulk samples for property measurements and device applications. A straightforward path is identified for the scale-up of thermoelectric materials synthesis containing nanostructured constituents for use in thermoelectric applications. We end with some vision of where the field of thermoelectrics is now heading.

393

GPHS-RTG system explosion test direct course experiment 5000. [General Purpose Heat Source-Radioisotope Thermoelectric Generator  

SciTech Connect

The General Purpose Heat Source-Radioisotope Thermoelectric Generator (GPHS-RTG) has been designed and is being built to provide electrical power for spacecrafts to be launched on the Space Shuttle. The objective of the RTG System Explosion Test was to expose a mock-up of the GPHS-RTG with a simulated heat source to the overpressure and impulse representative of a potential upper magnitude explosion of the Space Shuttle. The test was designed so that the heat source module would experience an overpressure at which the survival of the fuel element cladding would be expected to be marginal. Thus, the mock-up was placed where the predicted incident overpressure would be 1300 psi. The mock-up was mounted in an orientation representative of the launch configuration on the spacecraft to be used on the NASA Galileo Mission. The incident overpressure measured was in the range of 1400 to 2100 psi. The mock-up and simulated heat source were destroyed and only very small fragments were recovered. This damage is believed to have resulted from a combination of the overpressure and impact by very high velocity fragments from the ANFO sphere. Post-test analysis indicated that extreme working of the iridium clad material occurred, indicative of intensive impulsive loading on the metal.

Not Available

1984-03-01

394

The design of a source to simulate the gamma-ray spectrum emitted by a radioisotope thermoelectric generator  

NASA Technical Reports Server (NTRS)

A simulated source was designed to duplicate the gamma spectrum of a uniform cylindrical 2200-watt Pu02 radioisotope thermoelectric generator containing 81% Pu-238 and 1.2 ppm Pu-236. Gamma rays from the decay of Pu-238, Am-241, Pu-239, and the 0-18(alpha,n)Ne-21 reaction were catalogued in broad energy groups. Two 46- and one 22-mc Th-228 sources provided simulation at various times in the life of the fuel capsule up to 18 years, which covers the time span of an outer planet mission. Emission from Th-228 represents the overwhelming contribution of the gamma spectrum after the first few years. The sources, in the form of 13-inch rods, were placed in a concentric hole in a cylinder of depleted uranium, which provided shielding equivalent to the self-shielding of the fuel capsule. The thickness of the U-238 cylinder (0.55cm) was determined by Monte Carlo calculations to insure that the spectrum emerging from the simulated source matched that of the fuel capsule.

Reier, M.

1972-01-01

395

Thermoelectric thin film thermal coating systems  

NASA Technical Reports Server (NTRS)

Derivation of the fluid loop temperature profile for a model with thermoelectric devices (TED) attached is developed as a function of position, incident radiation intensity, input fluid loop temperature and TED current. The associated temperature of the radiator is also developed so that the temperature difference across the TED can be determined for each position. The temperature difference is used in determining optimum operating conditions and available generated electrical power.

Harpster, J. W.; Bulman, W. E.; Middleton, A. E.; Swinehart, P. R.; Braun, F. D.

1973-01-01

396

Thermoelectric system  

DOEpatents

In one particular embodiment, an internal combustion engine is provided. The engine comprises a block, a head, a piston, a combustion chamber defined by the block, the piston, and the head, and at least one thermoelectric device positioned between the combustion chamber and the head. In this particular embodiment, the thermoelectric device is in direct contact with the combustion chamber. In another particular embodiment, a cylinder head configured to sit atop a cylinder bank of an internal combustion engine is provided. The cylinder head comprises a cooling channel configured to receive cooling fluid, valve seats configured for receiving intake and exhaust valves, and thermoelectric devices positioned around the valve seats.

Reiners, Eric A. (Washington, IL) [Washington, IL; Taher, Mahmoud A. (Peoria, IL) [Peoria, IL; Fei, Dong (Peoria, IL) [Peoria, IL; McGilvray, Andrew N. (East Peoria, IL) [East Peoria, IL

2007-10-30

397

High-performance dispenser printed MA p-type Bi(0.5)Sb(1.5)Te(3) flexible thermoelectric generators for powering wireless sensor networks.  

PubMed

This work presents a novel method to synthesize p-type composite thermoelectric materials to print scalable thermoelectric generator (TEG) devices in a cost-effective way. A maximum ZT of 0.2 was achieved for mechanically alloyed (MA) p-type Bi0.5Sb1.5Te3 (8 wt % extra Te additive)-epoxy composite films cured at 250 °C. A 50% increase in Seebeck coefficient as a result of adding 8 wt % extra Te in stoichiometric Bi0.5Sb1.5Te3 contributed to the increase in ZT. To demonstrate cost-effective and scalable manufacturing, we fabricated a sixty element thermoelectric generator prototype with 5.0 mm × 600 ?m × 120 ?m printed dimensions on a custom designed polyimide substrate with thick metal contacts. The prototype TEG device produced a power output of 20.5 ?W at 0.15 mA and 130 mV for a temperature difference of 20 K resulting in a device areal power density of 152 ?W/cm(2). This power is sufficient for low power applications such as wireless sensor network (WSN) devices. PMID:24160841

Madan, Deepa; Wang, Zuoqian; Chen, Alic; Wright, Paul K; Evans, James W

2013-11-27

398

Development of superconducting AC generator  

SciTech Connect

A 50 MVA superconducting (AC) generator with a superconducting field winding was manufactured and tested. Conceptual design of a 1000 MW superconducting generator was carried out. Key components of the superconducting field winding, cryogenic multi-cylindrical rotor, helium cooling system and airgap armature winding were required to operate without problems for a long time. This paper describes test results for the 50 MVA generator and design results of the 1000 MW generator. Furthermore, a technical overview of superconducting generator development is made on the basis of these results.

Maki, N.; Yamaguchi, K.; Takahashi, M.; Shiobara, R.

1988-03-01

399

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

400

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

Microsoft Academic Search

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

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

2002-01-01

401

Development of a Laser Flash Apparatus for Thermal Diffusivity Measurement on Small Pieces Thermoelectric Materials  

Microsoft Academic Search

A laser flash apparatus has been improved to measure thermal diffusivities of small samples with diameter of 3 mm. To obtain high s\\/n ratio, background signal has been reduced by improving sample stage. To increase signal intensity for metallic samples, incident beam has been converged. On the other hand, for thermoelectric materials, incident beam intensity has been reduced by optical

C. H. Lee; T. Ohta; H. Takazawa; K. Ueno; C. Sekine; I. Shirotani

402

Creep properties of forged 2219 T6 aluminum alloy shell of general-purpose heat source-radioisotope thermoelectric generator  

SciTech Connect

The shell (2219 T6 aluminum forging) of the General Purpose Heat Source-Radioisotope Thermoelectric Generator was designed to retain the generator under sufficient elastic stress to secure it during space flight. A major concern was the extent to which the elastic stress would relax by creep. To determine acceptability of the shell construction material, the following proof tests simulating service were performed: 600 h of testing at 270/sup 0/C under 24.1 MPa stress followed by 10,000 h of storage at 177/sup 0/C under 55.1 MPa, both on the ground; and 10,000 h of flight in space at 270/sup 0/C under 34.4 MPa stress. Additionally, systematic creep testing was performed at 177 and 260/sup 0/C to establish creep design curves. The creep tests performed at 177/sup 0/C revealed comparatively large amounts of primary creep followed by small amounts of secondary creep. The early creep is believed to be abetted by unstable substructures that are annealed out during testing at this temperature. The creep tests performed at 270/sup 0/C showed normal primary creep followed by large amounts of secondary creep. Duplicate proof tests simulating the ground exposure conditions gave results that were in good agreement. The proof test simulating space flight at 270/sup 0/C gave 0.11% primary creep followed by 0.59% secondary creep. About 10% of the second-stage creep was caused by four or five instantaneous strains, which began at the 4500-h mark. One or two of these strain bursts, occurred in each of several other tests at 177 and 260/sup 0/C but were assessed as very moderate in magnitude. The effect is attributable to a slightly microsegregated condition remaining from the original cast structure.

Hammond, J.P.

1981-12-01

403

From local force-flux relationships to internal dissipations and their impact on heat engine performance: The illustrative case of a thermoelectric generator  

NASA Astrophysics Data System (ADS)

We present an in-depth analysis of the sometimes understated role of the principle of energy conservation in linear irreversible thermodynamics. Our case study is that of a thermoelectric generator (TEG), which is a heat engine of choice in irreversible thermodynamics, owing to the coupling between the electrical and heat fluxes. We show why Onsager's reciprocal relations must be considered locally and how internal dissipative processes emerge from the extension of these relations to a global scale: The linear behavior of a heat engine at the local scale is associated with a dissipation process that must partake in the global energy balance. We discuss the consequences of internal dissipations on the so-called efficiency at maximum power, in the light of our comparative analyses of exoreversibility and endoreversibility on the one hand and of two classes of heat engines, autonomous and periodically driven, on the other hand. Finally, basing our analysis on energy conservation, we also discuss recent works which claim the possibility to overcome the traditional boundaries on efficiency imposed by finite-time thermodynamics in thermoelectric systems with broken time-reversal symmetry; this we do by introducing a “thermal” thermopower and an “electrical” thermopower which permits an analysis of the thermoelectric response of the TEG considering a possible dissymmetry between the electrical/thermal and the thermal/electrical couplings.

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

2013-08-01

404

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

405

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.

2014-03-01

406

Novel thermoelectric materials  

Microsoft Academic Search

Several new approaches to the design of improved thermoelectric materials have stimulated a resurgence of interest in this very old field. Within the past two years materials have been developed that validated one or more of these new ideas. Perhaps the most significant development is the concept and realization of materials that conduct electricity like a crystalline solid but heat

Brian C Sales

1997-01-01

407

Thermoelectric efficiency and compatibility.  

PubMed

The intensive reduced efficiency eta(r) is derived for thermoelectric power generation (in one dimension) from intensive fields and currents, giving eta(r)=(E x J) divided by (- inverted Delta)T x J(S). The overall efficiency is derivable from a thermodynamic state function, Phi=1 divided by u + alphaT, where we introduce u=J divided by kappa (inverted Delta)T as the relative current density. The method simplifies the computation and clarifies the physics behind thermoelectric devices by revealing a new materials property s=(sqrt[1+zT]-1) divided by (alphaT), which we call the compatibility factor. Materials with dissimilar compatibility factors cannot be combined by segmentation into an efficient thermoelectric generator because of constraints imposed on u. Thus, control of the compatibility factor s is, in addition to z, essential for efficient operation of a thermoelectric device, and thus will facilitate rational materials selection, device design, and the engineering of functionally graded materials. PMID:14611561

Snyder, G Jeffrey; Ursell, Tristan S

2003-10-01

408

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

409

Nano-materials enabled thermoelectricity from window glasses.  

PubMed

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 m(2) 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

410

Development of a preprototype thermoelectric integrated membrane evaporation subsystem for water recovery  

NASA Technical Reports Server (NTRS)

A three-man urine water recovery preprototype subsystem using a new concept to provide efficient potable water recovery from waste fluids on extended duration space flights has been designed, fabricated, and tested. Low power, compactness, and gravity insensitive operation are featured in this vacuum distillation subsystem that combines a hollow fiber polysulfone membrane evaporator with a thermoelectric heat pump. Application and integration of these key elements have solved problems inherent in previous reclamation subsystem designs. The hollow fiber elements provide positive liquid/gas phase control with no moving parts other than a waste liquid recirculation pump and a product water withdrawal pump. Tubular membranes provide structural integrity, improving on previous flat sheet membrane designs. A thermoelectric heat pump provides latent energy recovery.

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

1980-01-01

411

Thermoelectric properties of silicon nanostructures  

Microsoft Academic Search

Semiconductor nanostructures are promising candidates for efficient thermoelectric energy conversion, with applications in\\u000a solid-state refrigeration and power generation. The design of efficient semiconductor thermocouples requires a thorough understanding\\u000a of both charge and heat transport; therefore, thermoelectricity in silicon-based nanostructures requires that both electronic\\u000a and thermal transport be treated on an equal footing. In this paper, we present semiclassical simulation of

Z. Aksamija; I. Knezevic

2010-01-01

412

Design and Implementation of a New Thermoelectric-Photovoltaic Hybrid Energy System for Hybrid Electric Vehicles  

Microsoft Academic Search

In this article, a new thermoelectric-photovoltaic hybrid energy system is proposed for hybrid electric vehicles. The key is to newly develop the multiple-input single-ended primary inductor converter to simultaneously regulate the thermoelectric and photovoltaic generators in such a way that the total output power can be maximized. Both design and implementation of the proposed system are discussed. Experimental results are

Xiaodong Zhang; K. T. Chau

2011-01-01

413

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

414

Thermoelectric micro power generator utilizing self-standing polysilicon-metal thermopile  

Microsoft Academic Search

A prototype self-standing polysilicon-metal junction thermopile has been developed. In order to realize ideal higher thermal isolation, a thermopile without a membrane and having self-standing structure is proposed. The hot and cold contacts in the proposed thermopile are reversible. The thermocouple is composed of an n-type polysilicon and an Au junction. The thermopile was fabricated by MICS (Micromachine Integrated Chip

Toshiyuki Toriyama; M. Yajima; S. Sugiyama

2001-01-01

415

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

416

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

417

Thermoelectric refrigerator  

NASA Technical Reports Server (NTRS)

A refrigerator is provided which combines the benefits of superinsulation materials with thermoelectric devices and phase change materials to provide an environmentally benign system that is energy efficient and can maintain relatively uniform temperatures for extended periods of time with relatively low electrical power requirements. The refrigerator includes a thermoelectric assembly having a thermoelectric device with a hot sink and a cold sink. The superinsulation materials include a plurality of vacuum panels. The refrigerator is formed from an enclosed structure having a door. The vacuum panels may be contained within the walls of the enclosed structure and the door. By mounting the thermoelectric assembly on the door, the manufacturer of the enclosed structure is simplified and the overall R rating of the refrigerator increased. Also an electrical motor and propellers may be mounted on the door to assist in the circulation of air to improve the efficiency of the cold sink and the hot sink. A propeller and/or impeller is preferably mounted within the refrigerator to assist in establishing the desired air circulation flow path.

Park, Brian V. (Inventor); Smith, Jr., Malcolm C. (Inventor); McGrath, Ralph D. (Inventor); Gilley, Michael D. (Inventor); Criscuolo, Lance (Inventor); Nelson, John L. (Inventor)

1996-01-01

418

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

419

Thermoelectric properties and electrode bonding performance for metal silicides  

Microsoft Academic Search

Thermoelectric properties of metal silicides and their electrode bonding performance have been examined. Metal silicides such as chromium silicide, magnesium silicide and so on are environmentally friendly and abundant. These characters are very much important for thermoelectric power generation application. The thermoelectric properties of these materials made by the hot-press sintering method followed with spark plasma sintering method make them

T. Kajikawa; T. Sugiyama; M. Serizawa; K. Kamio; M. Koike; T. Ohta; M. Omori

2001-01-01

420

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

421

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

422

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

423

New Approaches to Thermoelectric Materials  

Microsoft Academic Search

A deeper understanding of the parameters that affect the dimensionless figure of merit, the development of new concepts and\\u000a the use of innovative synthesis techniques has recently led to systems with better thermoelectric performances. Here we present\\u000a part of the work that has been recently performed in our groups in order to get new and improved thermoelectric systems. Two\\u000a new

A. P. Gonçalves; E. B. Lopes; E. Alves; N. P. Barradas; N. Franco; O. Rouleau; C. Godart

2009-01-01

424

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

425

Zintl phases for thermoelectric devices.  

PubMed

By converting waste heat into electricity and improving the efficiency of refrigeration systems, thermoelectric devices could play a significant role in solving today's energy problems. Increasing the thermoelectric efficiency (as measured by the thermoelectric material's figure-of-merit, zT) is critical to the development of this technology. Complex Zintl phases, in particular, make ideal candidates for thermoelectric materials because the necessary "electron-crystal, phonon-glass" properties can be engineered with an understanding of the Zintl chemistry. A recent example is the discovery that Yb(14)MnSb(11), a transition metal Zintl compound, has twice the zT as the material currently in use at NASA. This perspective outlines a strategy to discover new high zT materials in Zintl phases, and presents results pointing towards the success of this approach. PMID:17514328

Kauzlarich, Susan M; Brown, Shawna R; Snyder, G Jeffrey

2007-06-01

426

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

427

A High Resolution Dynamic Technique of Thermoelectric Power Measurements  

Microsoft Academic Search

A new technique, principally applicable to metals and alloys, has been developed for high resolution absolute thermoelectric power (TEP) and differential thermoelectric power measurements. It utilizes two continuously monitoring dc nanovolt amplifiers, one for the sample couple thermoelectric voltage and the other for a thermocouple voltage proportional to temperature differences developed across the samples. The outputs of these amplifiers are

Donald R. Zrudsky; Alan B. Showalter

1973-01-01

428

Detection of Thermal Radiation, Sensing of Heat Flux, and Recovery of Waste Heat by the Transverse Thermoelectric Effect  

NASA Astrophysics Data System (ADS)

The transverse thermoelectric effect is unique in that an output voltage can be extracted in the direction perpendicular to the input temperature gradient. This paper describes how this transverse feature can be exploited to realize simple and promising configurations of thermoelectric devices. For detection of thermal radiation, two-dimensional imaging has been demonstrated by a fabricated sensor array of tilt-oriented Ca x CoO2 epitaxial thin film. We have also developed a serpentine heat flux sensor made of multilayered Bi/Cu, and Bi0.5Sb1.5Te3/Ni tubular thermoelectric devices for power generation. The fabrication processes and test results are presented.

Kanno, Tsutomu; Takahashi, Kouhei; Sakai, Akihiro; Tamaki, Hiromasa; Kusada, Hideo; Yamada, Yuka

2014-06-01

429

Fabrication of Multilayer-Type Mn-Si Thermoelectric Device  

NASA Astrophysics Data System (ADS)

This research aims to develop a direct-contact manganese silicon p/ n multilayer-type thermoelectric power generation block. p-type MnSi1.74 and n-type Mn0.7Fe0.3Si1.68 ball-milled powders with diameter of about 10 ?m or less were mixed with polyvinyl butyl alcohol diluted with methylbenzene at pigment volume concentration of approximately 70%. The doctor-blade method produced 45- ?m-thick p- and n-type pigment plates. The insulator, i.e., powdered glass, was mixed with cellulose to form insulator slurry. Lamination of manganese silicide pigment layers and screen-printed insulator layers was carried out to fabricate multilayer direct-contact thermoelectric devices. Hot pressing and spark plasma sintering were carried out at 450°C and 900°C, respectively. Four to 30 thermoelectric (TE) p/ n pairs were fabricated in a 10 mm × 10 mm × 10 mm sintered TE block. The maximum output was 11.7 mW/cm2 at a temperature difference between 20°C and 700°C, which was about 1/85 of the ideal power generation estimated from the thermoelectric data of the bulk MnSi1.74 and Mn0.7Fe0.3Si1.68 materials. A power generation test using an engine test bench was also carried out.

Kajitani, T.; Ueno, T.; Miyazaki, Y.; Hayashi, K.; Fujiwara, T.; Ihara, R.; Nakamura, T.; Takakura, M.

2014-06-01

430

Thermoelectric Cooling Through Thermoelectric Materials  

Microsoft Academic Search

\\u000a Thermoelectric (TE) cooling has been used for thermal management of high-power-dissipating electrical components, with silent,\\u000a compact, reliable, and durable characteristics and being modulated to maintain a fixed temperature. However, TE coolers currently\\u000a in use have a coefficient of performance (COP) of only about 0.5. This is quite a low value compared with COPs of other cooling\\u000a approaches such as air

Xingcun Colin Tong

431

Combustion synthesis of thermoelectric oxides  

NASA Astrophysics Data System (ADS)

Thermoelectric materials can be used to convert temperature difference applied across them to a electrical energy. They can be used to recover waste heat and reuse it. Two thermoelectric materials, calcium cobaltate (Ca 1.24Co1.62O3.86) and yttrium cuprate (YCuO 2) were synthesized by two different types of combustion synthesis, Self-propagating High-temperature Synthesis (SHS) and thermal explosion. Combustion synthesis is more time and energy efficient than conventional methods of preparation of thermoelectric oxides. This work shows that combustion synthesis is a viable alternative for synthesis of thermoelectric oxides with comparable characteristics and thermoelectric performance to compounds prepared by traditional syntheses. Thermoelectric properties of calcium cobaltate were evaluated and compared to data published in recent literature. A finite element model of SHS is also developed. It can be used to study the reaction process of the synthesis in detail and can predict results of experiments. The model was validated by comparison with experimental observations.

Selig, Jiri

432

High Performance Thermoelectric Materials Using Solution Phase Synthesis of Narrow Bandgap Core/Shell Quantum Dots Deposited Into Colloidal Crystal Thin Films.  

National Technical Information Service (NTIS)

Thermoelectrics is the science and technology associated with thermoelectric converters, that is, the generation of electrical power based on the Seebeck effect and refrigeration by the Peltier effect. The attractive features of thermoelectric devices are...

2005-01-01

433

Temperature-entropy formulation of thermoelectric thermodynamic cycles.  

PubMed

A temperature-entropy formulation is derived for thermoelectric devices. Thermoelectric chiller and generator cycles can then be cast in the same irreversible thermodynamics framework commonly applied to conventional large-scale cooling and power generation equipment, including a transparent identification of the principal energy flows and performance bottlenecks (dissipation). Distinct differences in chiller versus generator mode are highlighted and illustrated with data from commercial thermoelectric units. PMID:12059651

Chua, H T; Ng, K C; Xuan, X C; Yap, C; Gordon, Jeffrey M

2002-05-01

434

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

435

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

436

Development of a Flexible Thermopile Power Generator Utilizing BiTe-Cu Thin Films  

NASA Astrophysics Data System (ADS)

In this paper, a thermoelectric generator with a flexible structure is presented. The thermoelectric generator consists of 1625 thermocouples made from two materials, i.e. n-type BiTe and Cu thin films, on a flexible polyimide sheet by utilizing micromachining technology. The prototype of the flexible thermoelectric generator has dimensions of 100mm × 80mm × 3mm (length × width × thickness). Theoretical calculations show an output voltage of 317mV/K and a power of 7.8?W/K2. Preliminary experimental results measured on the test thermocouple samples show an average Seebeck voltage of 58.8?V/K per one thermocouple was obtained. This thermoelectric generator structure can be bent flexibly, so it can be used on both flat and cylindrical surfaces, e.g. on the skin of human body.

Dao, Dzung Viet; Miyaoka, Akihiro; Sugiyama, Susumu; Ueno, Hiroshi; Itoigawa, Kouichi

437

Development of Advanced Stirling Radioisotope Generator for Space Exploration  

NASA Technical Reports Server (NTRS)

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 hig