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1

100 Watt Thermoelectric Generator Development.  

National Technical Information Service (NTIS)

The objective of the thermoelectric program conducted at the U. S. Electronics Command is to develop a silent thermoelectric generator using logistically available hydrocarbon fuels. A report is given of the results of evaluation of tests made on the Expl...

A. Herchakowski

1966-01-01

2

Progress in the development of high efficiency segmented thermoelectric generators  

Microsoft Academic Search

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

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

1999-01-01

3

Development of Next Generation Segmented Thermoelectric Radioisotope Power Systems  

Microsoft Academic Search

Radioisotope thermoelectric generators have been used for space-based applications since 1961 with a total of 22 space missions that have successfully used RTGs for electrical power production. The key advantages of radioisotope thermoelectric generators (RTGs) are their long life, robustness, compact size, and high reliability. Thermoelectric converters are easily scalable, and possess a linear current-voltage curve, making power generation easy

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

2005-01-01

4

Thermoelectric generator  

DOEpatents

A thermoelectric generator having a rigid coupling or stack'' between the heat source and the hot strap joining the thermoelements is described. The stack includes a member of an insulating material, such as ceramic, for electrically isolating the thermoelements from the heat source, and a pair of members of a ductile material, such as gold, one each on each side of the insulating member, to absorb thermal differential expansion stresses in the stack. (Official Gazette)

Pryslak, N.E.

1974-02-26

5

Development of Next Generation Segmented Thermoelectric Radioisotope Power Systems  

NASA Astrophysics Data System (ADS)

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

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

2005-12-01

6

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

7

Development and optimization of a stove-powered thermoelectric generator  

NASA Astrophysics Data System (ADS)

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

Mastbergen, Dan

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

Component for thermoelectric generator  

DOEpatents

In a thermoelectric generator, a component comprises a ceramic insulator, having over limited areas thereof, each area corresponding to a terminal end of thermoelectric wires, a coating of a first metal which adheres to the insulator, and an electrical thermoelectric junction including a second metal which wets said first metal and adheres to said terminal ends but does not wet said insulator, and a cloth composed of electrically insulating threads interlaced with thermoelectric wires.

Purdy, David L. (Indiana, PA)

1977-01-01

10

Development of PbTe material for advanced thermoelectric power generation  

NASA Astrophysics Data System (ADS)

In this paper, development of single crystalline n- and p- type PbTe crystals and PbTe bulk nanocomposites using PbTe nano powders and emerging field assisted sintering technology (FAST) are discussed. Materials requirements for efficient thermoelectric power generation using waste heat at intermediate temperature range (6500 to 8500 K) will be discussed. Recent results on production of n- and p- type PbTe crystals and their thermoelectric characterization will be presented. Relative characteristics and performance of PbTe bulk single crystals and nano composites for thermoelectric power generation will be discussed.

Prasad, Narasimha S.; Trivedi, Sudhir B.; Palosz, Witold; Rosemeier, Robert; Rosemeier, Cory; Kutcher, Susan; Mayers, David; Taylor, Patrick J.; Maddux, Jay; Singh, Jogender

2012-05-01

11

Modular Isotopic Thermoelectric Generator  

SciTech Connect

Advanced RTG concepts utilizing improved thermoelectric materials and converter concepts are under study at Fairchild for DOE. The design described here is based on DOE's newly developed radioisotope heat source, and on an improved silicon-germanium material and a multicouple converter module under development at Syncal. Fairchild's assignment was to combine the above into an attractive power system for use in space, and to assess the specific power and other attributes of that design. The resultant design is highly modular, consisting of standard RTG slices, each producing ~24 watts at the desired output voltage of 28 volt. Thus, the design could be adapted to various space missions over a wide range of power levels, with little or no redesign. Each RTG slice consists of a 250-watt heat source module, eight multicouple thermoelectric modules, and standard sections of insulator, housing, radiator fins, and electrical circuit. The design makes it possible to check each thermoelectric module for electrical performance, thermal contact, leaktightness, and performance stability, after the generator is fully assembled; and to replace any deficient modules without disassembling the generator or perturbing the others. The RTG end sections provide the spring-loaded supports required to hold the free-standing heat source stack together during launch vibration. Details analysis indicates that the design offers a substantial improvement in specific power over the present generator of RTGs, using the same heat source modules. There are three copies in the file.

Schock, Alfred

1981-04-03

12

Materials for Vehicular Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

The specific operating conditions of thermoelectric generators in vehicles determine the requirements for thermoelectric materials used in them. The present work analyzes which materials are the most suitable for solving the task of heat recovery from internal combustion engines. Requirements for such materials and optimization of thermoelectric modules on their basis are formulated. The most important of them include specific cost, efficiency, cyclic stability, service life, and optimal operating temperature range. Thermoelectric materials were prepared, and on their basis a series of generator thermoelectric modules created to optimize all of the above parameters for operation in vehicular thermoelectric generators.

Anatychuk, L. I.; Kuz, R. V.

2012-06-01

13

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

14

Modular Isotopic Thermoelectric Generator  

SciTech Connect

Advanced RTG concepts utilizing improved thermoelectric materials and converter concepts are under study at Fairchild for DOE. The design described here is based on DOE's newly developed radioisotope heat source, and on an improved silicon-germanium material and 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.

Schock, Alfred

1981-01-01

15

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

16

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

17

Alkali metal thermoelectric generator  

SciTech Connect

This patent describes a thermoelectric generator. It comprises a sealed heated chamber with one wall portion being a first side of a wall constructed of a selectively porous material through which only ions of a working fluid can migrate; a first capillary wick structure located in the interior of the heated chamber and in contact with a wall of the heated chamber at a heat source and at the wall portion of selectively porous material; a second capillary wick structure located within the interior of the heated chamber and in contact with a wall of the heated chamber at a heat source; a sealed second chamber with one wall portion being the second side of the same wall of selectively porous material as is in the heated chamber and another wall which is cooled; a third capillary wick structure located in the interior of the second chamber and in contact with the cooled wall of the second chamber; a capillary structure fluid return path interconnecting the second capillary wick structure within the heated chamber and the third capillary wick structure within the second chamber; a first electrical connector attached to the heated chamber and in electrical contact with a working fluid on the wall of porous material in the heated chamber; a second electrical connector attached to the second chamber and in electrical contact with a working fluid on the wall of porous material in the cooled chamber; a quantity of liquifiable and vaporizable working fluid which is ionized by heating and of which only the ions can migrate through the wall portion of porous material; and at least one heat source applying heat to the heated chamber.

Ernst, D.M.

1989-08-15

18

Thermoelectric development at Hi-Z technology  

Microsoft Academic Search

An improved thermoelectric generator (TEG) for the heavy duty class eight diesel trucks is under development at Hi-Z Technology. The current TEG is equipped with the improved HZ-14 thermoelectric module, which features better mechanical properties as well as higher electric power output. Also, the modules are held in place more securely. The TEG is comprised of 72 TE modules, which

Aleksandr S. Kushch; John C. Bass; Saeid Ghamaty; N. B. Eisner

2001-01-01

19

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

20

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

21

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

22

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

23

Radioisotope thermoelectric generators for implanted pacemakers  

SciTech Connect

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 /sup 238/PuO/sub 2/ with a specific neutron yield of 3.10/sup 3/-4.10/sup 3/ (g /SUP ./ sec)/sup -1/, equivalent to metallic Pu 238, and with a content of gamma impurities sufficient to ensure a permissible exposure a permissible exposure does rate (EDR) of a mixture of neutron and gamma radiation. After carrying out the isotope exchange and purifying the initial sample of its gamma impurity elements, the authors obtain biomedical Pu 238 satisfying the indicated requirements king suitable for use in the power packs of medical devices. Taking the indicated specifications into account, the Ritm-1o and gamma radioisotope heat sources were designed, built, tested in models and under natural conditions, and then into production as radioisotope thermoelectric generators designed to power the electronic circuits of implanted pacemakers. The Ritm-MT and Gemma radioisotope thermoelectric generators described are basic units, which can be used as self-contained power supplies for electronic equipment with power requirements in the micromilliwatt range.

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

1986-08-01

24

Radioisotope thermoelectric generator reliability and safety  

SciTech Connect

There are numerous occasions when a planetary mission requires energy in remote areas of the solar system. Anytime power is required much beyond Mars or the Asteroid Belts, solar power is not an option. The radioisotope thermoelectric generator (RTG) was developed for such a mission requirement. It is a relatively small and lightweight power source that can produce power under adverse conditions. Just this type of source has become the backbone of the power system for far outer plant exploration. Voyagers I and II are utilizing RTGs, which will soon power the Galileo spacecraft to Jupiter and the Ulysses spacecraft to study the solar poles. The paper discusses RTG operation including thermoelectric design, converter design, general-purpose heat source; RTG reliability including design, testing, experience, and launch approval; and RTG safety issues and methods of ensuring safety.

Campbell, R.; Klein, J.

1989-01-01

25

Dispenser printed composite thermoelectric thick films for thermoelectric generator applications  

NASA Astrophysics Data System (ADS)

This paper describes novel processes for preparing thermoelectric composite materials compatible with thick film dispenser printing fabrication processes. Optimization of process parameters to improve thermoelectric properties is introduced. We explore the use of n-type Bi2Te3 and p-type Sb2Te3 materials to achieve properties suitable for use in low cost high aspect ratio microscale thermoelectric generators. Printable thermoelectric inks consisted of dispersed semiconductor powders in an epoxy resin system. Thick films were printed on glass substrates and cured at temperatures ranging from 150 to 350 °C. The best achievable power factors for n-type Bi2Te3-epoxy and p-type Sb2Te3-epoxy composite films were 1.5×10-4 W/m K2 and 8.4×10-4 W/m K2, respectively. Figure of merit (ZT) values for n-type Bi2Te3-epoxy and p-type Sb2Te3-epoxy composites were 0.16 and 0.41, respectively, which are much higher than previously reported ZT values for composite thermoelectric materials.

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

2011-02-01

26

Thermoelectric power generation for hybrid-electric vehicle auxiliary power  

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

27

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

28

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.

Bell, Lon E; Crane, Douglas Todd

2013-05-21

29

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

30

Relation Between Electric Power and Temperature Difference for Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

The thermoelectric generation is the direct energy conversion method from heat to electric power. The conversion method is a very useful utilization of waste energy because of its possibility using a thermal energy below 423K. This research objective is to establish the thermoelectric technology on an optimum system design method and efficiency, and cost effective thermoelectric element in order to extract the maximum electric power from a wasted hot water. This paper is considered in manufacturing a thermoelectric generator and manufacturing of thermoelectric generator with 32 thermoelectric modules. It was also found that the electric voltage of thermoelectric generator with 32 modules slowly changed along temperature differences and the maximum power of thermoelectric generator using thermoelectric generating modules can be defined as temperature function.

Woo, Byung Chul; Lee, Hee Woong

31

USING THERMOELECTRIC GENERATORS TO INCREASE ENGINE FUEL EFFICIENCY  

Microsoft Academic Search

Thermoelectric generators capture the excess exhaust heat generated by a combustion engine and convert the heat into electricity. The main goal is that thermoelectric generators will increase fuel efficiency in automobiles. A thermoelectric generator is made up of a series of metal pipes covered with a semiconductor. The pipes are heated and the electrons from the side that is heated

Jerald Daniels

32

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

Microsoft Academic Search

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

Velimir Jovanovic; Saeid Ghamaty

2006-01-01

33

Thermoelectric generator having a resiliently mounted removable thermoelectric module  

DOEpatents

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

Purdy, David L. (Indiana, PA); Shapiro, Zalman M. (Pittsburgh, PA); Hursen, Thomas F. (Monroeville, PA); Maurer, Gerould W. (Apollo, PA)

1976-11-02

34

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

SciTech Connect

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

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

1996-11-01

35

New thermoelectric materials and devices for terrestrial power generators  

NASA Astrophysics Data System (ADS)

The development of new, more efficient, materials and devices is the key to expand the range of applications of thermoelectric generators. New potential terrestrial applications have been recently described in the literature. There exists a wide range of heat source temperatures for these applications, from low grade waste heat, at 320-350K, up to 80 to 1100K, such as in the heat recovery from a processing plant of combustible solid waste. The automobile industry has also recently developed a strong interest in a waste exhaust heat recovery power source operating in the 375-775K temperature range to supplement or replace the alternator and thus decrease fuel consumption. Because of the relatively small temperature drop across the generator and of the generator mass requirements, it is estimated that values of 1.5 to 2.0 are needed for the dimensionless thermoelectric figure of merit, ZT, in order to develop an economically viable system. Of course, there are other factors besides ZT when considering the potential use of thermoelectrics. For example, most commercial applications also require that the materials have also to be cheap enough, or environmentally friendly to make the thermoelectric power generation a viable option. Due to the need for reductions in the mass, cost and volume of radioisotope thermoelectric generators (RTGs) used to power spacecrafts for deep space missions, a search for new advanced materials with ZT values substantially higher than state-of-the-art Si0.8Ge0.2 alloys (ZTSiGe Å 0.65 from 575 to 1275K) was initiated a few years ago at the Jet Propulsion Laboratory. Recent results on novel materials have demonstrated that ZT values significantly larger than 1.0 could be obtained in the 475 to 975K temperature range. These materials are excellent candidates to be used in terrestrial thermoelectric power generators using waste heat or liquid fuels.

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

1997-01-01

36

Internal convection in thermoelectric generator models  

NASA Astrophysics Data System (ADS)

Coupling between heat and electrical currents is at the heart of thermoelectric processes. In a thermoelectric system this may be seen, from a thermal viewpoint, as an additional thermal flux linked to the appearance of an electrical current. Since this additional flux is associated with the global displacement of charge carriers in the system, it can be qualified as convective in opposition to the conductive part related to both phonon transport and heat transport by electrons under open circuit condition as, e.g., in the Wiedemann-Franz relation. In this article we demonstrate that considering the convective part of the thermal flux allows both new insight into the thermoelectric energy conversion and the derivation of the maximum power condition for generators with realistic thermal coupling.

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

2012-11-01

37

Solar hybrid systems with thermoelectric generators  

Microsoft Academic Search

The possibility of using of thermoelectric generators in solar hybrid systems has been investigated. Four systems were examined, one working without radiation concentration, of the traditional PV\\/Thermal geometry, but with TEGs between the solar cells and heat extractor, and three other using concentrators, namely: concentrator – TEG ? heat extractor, concentrator ? PV cell ? TEG ? heat extractor, and

E. A. Chávez-Urbiola; Yu. V. Vorobiev; L. P. Bulat

38

Thin-film thermoelectric generator element characterization  

Microsoft Academic Search

A thermoelectric power generator using thin-film materials presents many challenges due to its inherently large temperature gradient and correspondingly large power density. We present measurements of generated power density from BiTe-based thin-film and thick-film single-element devices (Marlow) in a variety of different element lengths (150-1500 micron) with an experimental setup capable of generating a large temperature difference (>300 K) across

Peter Mayer; Rajeev J. Ram

2005-01-01

39

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

40

Multi-mission radioisotope thermoelectric generator (MMRTG) program overview  

Microsoft Academic Search

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

Fred Ritz; C. E. Peterson

2004-01-01

41

Power-flattening techniques for radioisotopic thermoelectric generators. Final report  

SciTech Connect

The objective of this program was to investigation of a novel means of reducing the potential ecologic hazards that may be associated with radiosotopic thermoelectric generators (RTG's). A number of short-lived isotopes have lower toxicities and are more ecologically acceptable than the Plutonium 238 used at present. In addition, the shorter half lives significantly reduce the time period during which isotope encapsulation must be assured (approximately 10 half lives). The technical approach involves the use of a gas-controlled heat pipe to maintain a nearly constant heat input to the thermoelectric converter in spite of the decay profile of a short-lived isotopic heat source. Excess thermal power available early in life, is automatically shorted around the thermoelectric module by way of the heat pipe. A development model of a gas-controlled heat pipe capable of performing the required task was constructed and tested during this program.

Eastman, G.Y.

1984-07-01

42

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

43

Effect of heat transfer on the performance of thermoelectric generator-driven thermoelectric refrigerator system  

NASA Astrophysics Data System (ADS)

A model of thermoelectric generator-driven thermoelectric refrigerator with external heat transfer is proposed. The performance of the combined thermoelectric refrigerator device obeying Newton's heat transfer law is analyzed using the combination of finite time thermodynamics and non-equilibrium thermodynamics. Two analytical formulae for cooling load vs. working electrical current, and the coefficient of performance (COP) vs. working electrical current, are derived. For a fixed total heat transfer surface area of four heat exchangers, the allocations of the heat transfer surface area among the four heat exchangers are optimized for maximizing the cooling load and the coefficient of performance (COP) of the combined thermoelectric refrigerator device. For a fixed total number of thermoelectric elements, the ratio of number of thermoelectric elements of the generator to the total number of thermoelectric elements is also optimized for maximizing both the cooling load and the COP of the combined thermoelectric refrigerator device. The influences of thermoelectric element allocation and heat transfer area allocation are analyzed by detailed numerical examples. Optimum working electrical current for maximum cooling load and COP at different total number of thermoelectric elements and different total heat transfer area are obtained, respectively.

Chen, Lingen; Meng, Fankai; Sun, Fengrui

2012-01-01

44

Thermoelectric material development. Final report  

SciTech Connect

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

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

1994-10-01

45

CFD modeling of thermoelectric generators in automotive EGR-coolers  

NASA Astrophysics Data System (ADS)

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

Högblom, Olle; Andersson, Ronnie

2012-06-01

46

Potential for Usage of Thermoelectric Generators on Ships  

NASA Astrophysics Data System (ADS)

The useful waste heat potential for a bulk carrier has been evaluated as a preliminary step towards developing a thermoelectric generator (TEG) waste heat recovery system for ships. A medium-sized bulk carrier produces 6.2 MW of waste heat, and the most promising usable sources for the TEG are shown herein to be the exhausts from the main engine and the sludge oil incinerator.

Kristiansen, N. R.; Nielsen, H. K.

2010-09-01

47

Autonomous Underwater Vehicle Thermoelectric Power Generation  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

48

Thermal and power generating performances of thermoelectric energy recovery modules  

Microsoft Academic Search

This paper seeks to demonstrate the performance of a thermoelectric energy recovery module (TERM). The TERM aims to convert the waste heat from power amplifier (PA) transistors into the useful power. The TERM contains a thermoelectric generator (TEG), a heat spreader, and a heat sink. A first order prototype of the TERM is generated and used as a test vehicle.

Kyoung Joon Kim

2010-01-01

49

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

National Technical Information Service (NTIS)

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 containmen...

D. R. Bronowski M. M. Madsen

1991-01-01

50

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.

2013-10-01

51

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

52

Thermoelectric module construction for low temperature gradient power generation  

Microsoft Academic Search

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

Y. Meydbray; R. Singh; Ali Shakouri

2005-01-01

53

Parametric thermal analysis of the performance of a thermoelectric generator  

NASA Astrophysics Data System (ADS)

A parametric analysis is presented for the performance of a thermoelectric generator based on its operating conditions. The mathematical model, consisting of non linear equations, is made dimensionless to allow the characteristic parameters to be evidenced. The proposed parameterization lends generality to the results obtained. In particular the relationships have been investigated between the temperature difference inside the thermoelectric cell and that on the outside of the generator, and the effect of the outer thermal resistances of the generator on the working conditions. These parameters have a significant effect on the efficiency and therefore on the optimization of the operating conditions of the thermoelectric generator.

Casano, G.; Piva, S.

2012-11-01

54

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

55

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

56

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

Microsoft Academic Search

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

Schock

1983-01-01

57

Recent Developments in Semiconductor Thermoelectric Physics and Materials  

NASA Astrophysics Data System (ADS)

Recent advances in semiconductor thermoelectric physics and materials are reviewed. A key requirement to improve the energy conversion efficiency is to increase the Seebeck coefficient (S) and the electrical conductivity (?) while reducing the electronic and lattice contributions to thermal conductivity (?e + ?L). Some new physical concepts and nanostructures make it possible to modify the trade-offs between the bulk material properties through changes in the density of states, scattering rates, and interface effects on electron and phonon transport. We review recent experimental and theoretical results on nanostructured materials of various dimensions: superlattices, nanowires, nanodots, and solid-state thermionic power generation devices. Most of the recent success has been in the reduction of lattice thermal conductivity with the concurrent maintenance of good electrical conductivity. Several theoretical and experimental results to improve the thermoelectric power factor (S2?) and to reduce the Lorenz number (?/?e) are presented. We briefly describe recent developments in nonlinear thermoelectrics, as well as the generalization of the Bergman theorem for composite materials. Although the material thermoelectric figure of merit Z [=S2?/(?e + ?L)] is a key parameter to optimize, one has to consider the whole system in an energy conversion application. A rarely discussed but important efficiency/cost trade-off for thermoelectric power generation is briefly reviewed, and research directions for the development of low-cost thermoelectric materials are identified. Finally, we highlight the importance of the figure of merit, Z, beyond macroscale energy conversion applications in describing the microscopic coupling between charge and energy transport in materials.

Shakouri, Ali

2011-08-01

58

Thermoelectric generator and method for the fabrication thereof  

SciTech Connect

A method is described for fabricating a thermoelectric generator comprising the steps of: forming substrates with a thermally conductive and electrically conductive metallic plate on at least one surface of each substrate; forming at least one thin thermoelectric semiconductor element on the plates of some of the substrates to form a first thermal and electrical junction at the interface of the substrate plate and the thermoelectric semiconductor element on the substrates; using others of the substrates as superstrates and connecting the plate of each superstrate to the side of the thermoelectric semiconductor element opposite the substrate to form a second thermal and electrical junction at the interface of each superstrate plate and the respective thermoelectric semiconductor. Modules are formed with each module comprising the thin thermoelectric semiconductor element located between a substrate and a superstrate; and using modules to form a thermoelectric generator by arranging the modules so that one junction of each module is positioned adjacent and in thermal contact with a hot fluid carrying conduit and the other junction of each module is positioned adjacent and in thermal contact with a cold fluid carrying conduit.

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

1987-03-17

59

An overview of the Radioisotope Thermoelectric Generator Transportation System Program  

SciTech Connect

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

McCoy, J.C.; Becker, D.L. [Westinghouse Hanford Company, P.O. Box 1970, Richland, Washington 99352 (United States)

1996-03-01

60

An overview of the Radioisotope Thermoelectric Generator Transporation System Program  

SciTech Connect

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

McCoy, J.C.

1995-10-01

61

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

62

Investigation of Maximum Power Point Tracking for Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

In this paper, a thermoelectric generator (TEG) model is developed as a tool for investigating optimized maximum power point tracking (MPPT) algorithms for TEG systems within automotive exhaust heat energy recovery applications. The model comprises three main subsystems that make up the TEG system: the heat exchanger, thermoelectric material, and power conditioning unit (PCU). In this study, two MPPT algorithms known as the perturb and observe (P&O) algorithm and extremum seeking control (ESC) are investigated. A synchronous buck-boost converter is implemented as the preferred DC-DC converter topology, and together with the MPPT algorithm completes the PCU architecture. The process of developing the subsystems is discussed, and the advantage of using the MPPT controller is demonstrated. The simulation results demonstrate that the ESC algorithm implemented in combination with a synchronous buck-boost converter achieves favorable power outputs for TEG systems. The appropriateness is by virtue of greater responsiveness to changes in the system's thermal conditions and hence the electrical potential difference generated in comparison with the P&O algorithm. The MATLAB/Simulink environment is used for simulation of the TEG system and comparison of the investigated control strategies.

Phillip, Navneesh; Maganga, Othman; Burnham, Keith J.; Ellis, Mark A.; Robinson, Simon; Dunn, Julian; Rouaud, Cedric

2013-07-01

63

Simulations for the Development of Thermoelectric Measurements  

NASA Astrophysics Data System (ADS)

In thermoelectricity, continuum theoretical equations are usually used for the calculation of the characteristics and performance of thermoelectric elements, modules or devices as a function of external parameters (material, geometry, temperatures, current, flow, load, etc.). An increasing number of commercial software packages aimed at applications, such as COMSOL and ANSYS, contain vkernels using direct thermoelectric coupling. Application of these numerical tools also allows analysis of physical measurement conditions and can lead to specifically adapted methods for developing special test equipment required for the determination of TE material and module properties. System-theoretical and simulation-based considerations of favorable geometries are taken into account to create draft sketches in the development of such measurement systems. Particular consideration is given to the development of transient measurement methods, which have great advantages compared with the conventional static methods in terms of the measurement duration required. In this paper the benefits of using numerical tools in designing measurement facilities are shown using two examples. The first is the determination of geometric correction factors in four-point probe measurement of electrical conductivity, whereas the second example is focused on the so-called combined thermoelectric measurement (CTEM) system, where all thermoelectric material properties (Seebeck coefficient, electrical and thermal conductivity, and Harman measurement of zT) are measured in a combined way. Here, we want to highlight especially the measurement of thermal conductivity in a transient mode. Factors influencing the measurement results such as coupling to the environment due to radiation, heat losses via the mounting of the probe head, as well as contact resistance between the sample and sample holder are illustrated, analyzed, and discussed. By employing the results of the simulations, we have developed an improved sample head that allows for measurements over a larger temperature interval with enhanced accuracy.

Zabrocki, Knud; Ziolkowski, Pawel; Dasgupta, Titas; de Boor, Johannes; Müller, Eckhard

2013-07-01

64

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

65

Radiation Environments and Exposure Considerations for the Multi-Mission Radioisotope Thermoelectric Generator  

Microsoft Academic Search

The Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) is the next generation (RTG) being developed by DOE to provide reliable, long-life electric power for NASA's planetary exploration programs. The MMRTG is being developed by Pratt & Whitney Rocketdyne and Teledyne Energy Systems Incorporated (TESI) for use on currently planned and projected flyby, orbital and planet landing missions. This is a significant departure

William M. Kelly; Nora M. Low; Andrew Zillmer; Gregory A. Johnson; Eugene Normand

2006-01-01

66

SNAP15A Radioisotope Thermoelectric Generator  

Microsoft Academic Search

In the output power range below one electrical watt, the combination of an isotope heat source with a metallic thermoelectric converter yields characteristics that are superior to systems employing other kinds of energy sources or conversion methods. When the output power is to be delivered at a high impedance, the metallic thermocouple shows a substantial advantage over the semiconductor thermocouples.

R. J. Campana

1966-01-01

67

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

68

Clean Diesel Engine Component Improvement Program Diesel Truck Thermoelectric Generator  

SciTech Connect

Hi-Z Technology, Inc. (Hi-Z) is currently developing four different auxiliary generator designs that are used to convert a portion (5 to 20%) of the waste heat from vehicle engines exhaust directly to electricity. The four designs range from 200 Watts to 10 kW. The furthest along is the 1 kW Diesel Truck Thermoelectric Generator (DTTEG) for heavy duty Class 8 Diesel trucks, which, under this program, has been subjected to 543,000 equivalent miles of bouncing and jarring on PACCARâ??s test track. Test experience on an earlier version of the DTTEG on the same track showed the need for design modifications incorporated in DTTEG Mod 2, such as a heavy duty shock mounting system and reinforcement of the electrical leads mounting system, the thermocouple mounting system and the thermoelectric module restraints. The conclusion of the 543,000 mile test also pointed the way for an upgrading to heavy duty hose or flex connections for the internal coolant connections for the TEG, and consideration of a separate lower temperature cooling loop with its own radiator. Fuel savings of up to $750 per year and a three to five year payback are believed to be possible with the 5 % efficiency modules. The economics are expected to improve considerably to approach a two year payback when the 5 kW to 10 kW generators make it to the market in a few years with a higher efficiency (20%) thermoelectric module system called Quantum Wells, which are currently under development by Hi-Z. Ultimately, as automation takes over to reduce material and labor costs in the high volume production of QW modules, a one year payback for the 5 kW to10 kW generator appears possible. This was one of the stated goals at the beginning of the project. At some future point in time, with the DTTEG becoming standard equipment on all trucks and automobiles, fuel savings from the 25% conversion of exhaust heat to useable electricity nationwide equates to a 10% reduction in the 12 to 15 million barrels per day of imported oil, that much less air pollution, and an equivalent reduction in the trade deficit, which is expected to lower the inflation rate.

N.B. Elsner; J.C. Bass; S. Ghamaty; D. Krommenhoek; A. Kushch; D. Snowden; S. Marchetti

2005-03-31

69

A Thermoelectric Generation System and Its Power Electronics Stage  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

70

An overview of the Radioisotope Thermoelectric Generator Transporation System Program  

Microsoft Academic Search

Radioisotope Thermoelectric Generators (RTG) convert the heat generated by radioactive decay to electricity using thermocouples. RTGs have a long operating life, are reasonably lightweight, and require little or no maintenance once assembled and tested. These factors make RTGs particularly attractive for use in spacecraft However, because RTGs contain significant quantities of radioactive materials, normally plutonium-238 and its decay products, they

McCoy

1995-01-01

71

Design, Fabrication and testing of quantum well thermoelectric generator  

Microsoft Academic Search

A prototype energy-harvesting thermoelectric generator (TEG) is being designed, fabricated and tested to provide power for wireless sensors used in health monitoring of Navy ship machinery. TEGs utilize the heat transfer between shipboard waste heat sources and the ambient air to generate electricity directly and without any moving parts. In order to satisfy the required small design volume of 16.4

Velimir Jovanovic; Saeid Ghamaty; Norbert B. Elsner

2006-01-01

72

Thermoelectric generator hidden in a shirt with a fabric radiator  

NASA Astrophysics Data System (ADS)

Integration of thermopiles in garments has been performed in this work in different ways. It is shown that textile has a minor effect on power generation, which enables completely hidden and unobtrusive energy harvester. A one-milliwatt thermoelectric generator is then integrated between two layers of a shirt and its characteristics are reported.

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

2012-06-01

73

Study on iron disilicide thermoelectric generator  

NASA Astrophysics Data System (ADS)

A theoretical study is done on the thermoelectric material iron disilicide. The N type is doped with cobalt, the P type can either be doped Al or Mn. A small prototype is built enabling heat flux measurements. The efficiencies were measured for the KOMATSU couples which have Al doped P typed logs. The unit produced with 18 couples 0.75 watts. The efficiency of a couple alone (ration of electrical power by thermal power through the couple) is around 1 percent.

Stockholm, John G.; Scherrer, Hubert; Schlicklin, Philippe

1988-06-01

74

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

75

Radioisotope thermoelectric generator licensed hardware package and certification tests  

Microsoft Academic Search

This paper presents the Licensed Hardware package and the Certification Test portions of the Radioisotope Thermoelectric Generator Transportation System. This package has been designed to meet those portions of the Code of Federal Regulations (10 CFR 71) relating to 'Type B' shipments of radioactive materials. The detailed information for the anticipated license is presented in the safety analysis report for

L. H. Goldmann; H. S. Averette

1994-01-01

76

Progress Towards Maximizing the Performance of a Thermoelectric Power Generator  

Microsoft Academic Search

This paper describes the design, modeling, initial build and testing of a novel thermoelectric power generator (TPG), incorporating state of the art material technology with optimized thermal management. A numerical model simulates the operation of the device and facilitates its design. Advanced multi-parameter, gradient-based optimization techniques are used to better understand the interactions between various design variables and parameters in

D. T. Crane; L. E. Bell

2006-01-01

77

Analytical thermal model validation for Cassini radioisotope thermoelectric generator  

Microsoft Academic Search

The Saturn-bound Cassini spacecraft is designed to rely, without precedent, on the waste heat from its three radioisotope thermoelectric generators (RTGs) to warm the propulsion module subsystem, and the RTG end dome temperature is a key determining factor of the amount of waste heat delivered. A previously validated SINDA thermal model of the RTG was the sole guide to understanding

Edward L Lin

1997-01-01

78

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

2013-10-01

79

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

NASA Astrophysics Data System (ADS)

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

Arias, F. J.

80

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

81

Tests of General Instrument Corporation Model G1OC-X Thermoelectric Generator.  

National Technical Information Service (NTIS)

The thermoelectric power supply was developed for use in unmanned aids to navigation. The Model 1 G1OC-X has a rated output from the voltage converter of 7 watts. It is an air-cooled, propane-fueled generator which uses bismuth telluride thermocouples and...

1965-01-01

82

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

83

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

84

Proof-of-principle test for thermoelectric generator for diesel engines; Final report  

SciTech Connect

In September of 1987, the principals of what is now Hi-Z TECHNOLOGY, INC. applied to the National Bureau of Standards (now National Institute of Standards and Technology, NIST) under the Energy Related Inventions Program. The invention was entitled ``Thermoelectric Generator for Diesel Engines.`` The National Institute of Standards and Technology evaluated the invention and on January 12, 1989 forwarded Recommendation Number 455 to the Department of Energy (DOE). This recommendation informed the DOE that the invention had been selected for recommendation by the NIST for possible funding by the DOE. Following the recommendation of the NIST, the DOE contacted Hi-Z to work out a development program for the generator. A contract for a grant to design, fabricate, and test a Proof-of-Principle exhaust powered thermoelectric generator for Diesel engines was signed October 19, 1989. Hi-Z provided the thermoelectric modules used in the generator as their contribution to the project. The purpose of this Grant Program was to design, build, and test a small-scale, Proof-of-Principle thermoelectric generator for a Diesel engine. 15 figs., 1 tab.

NONE

1991-07-26

85

Thermoelectric energy converter for generation of electricity from low-grade heat  

Microsoft Academic Search

A thermoelectric energy conversion device which includes a plurality of thermoelectric elements is described. A hot liquid is supplied to one side of each element and a cold liquid is supplied to the other side of each element. The thermoelectric generator may be utilized to produce power from low-grade heat sources such as ocean thermal gradients, solar ponds, and low-grade

T. S. Jayadev; D. K. Benson

1980-01-01

86

Radiation Environments and Exposure Considerations for the Multi-Mission Radioisotope Thermoelectric Generator  

Microsoft Academic Search

The Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) is the next generation (RTG) being developed by DOE to provide reliable, long-life electric power for NASA’s planetary exploration programs. The MMRTG is being developed by Pratt & Whitney Rocketdyne and Teledyne Energy Systems Incorporated (TESI) for use on currently planned and projected flyby, orbital and planet landing missions. This is a significant departure

William M. Kelly; Nora M. Low; Andrew Zillmer; Gregory A. Johnson; Eugene Normand

2006-01-01

87

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

88

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

89

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

90

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

91

Radioisotope thermoelectric generator/thin fragment impact test  

NASA Astrophysics Data System (ADS)

The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of 238Pu 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 converter housing, failure of one fueled clad, and release of a small quantity of fuel.

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

1998-01-01

92

Multi-Watt Small Radioisotope Thermoelectric Generator Conceptual Design Study  

NASA Astrophysics Data System (ADS)

A need has been identified for a small, light-weight, reliable power source using a radioisotope heat source, to power the next generation of NASA's small surface rovers and exploration probes. Unit performance, development costs, and technical risk are key criteria to be used to select the best design approach. Because safety can be a major program cost and schedule driver, RTG designs should utilize the DOE radioisotope safety program's data base to the maximum extent possible. Other aspects important to the conceptual design include: 1) a multi-mission capable design for atmospheric and vacuum environments, 2) a module size based on one GPHS Step 2 module, 3) use of flight proven thermoelectric converter technologies, 4) a long service lifetime of up to 14 years, 5) maximize unit specific power consistent with all other requirements, and 6) be ready by 2013. Another critical aspect of the design is the thermal integration of the RTG with the rover or probe's heat rejection subsystem and the descent vehicle's heat rejection subsystem. This paper describes two multi-watt RTG design concepts and their integration with a MER-class rover.

Determan, William R.; Otting, William; Frye, Patrick; Abelson, Robert; Ewell, Richard; Miyake, Bob; Synder, Jeff

2007-01-01

93

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.

2011-12-01

94

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

Microsoft Academic Search

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

F. K. Eggleston; N. Fuschillo

1965-01-01

95

Milliwatt-Power Radioisotope Thermoelectric Generator (RTG) Based on Plutonium-238  

NASA Astrophysics Data System (ADS)

Results of design and experimental studies aimed at developing a milliwatt-power radioisotope thermoelectric generator (RTG) based on plutonium-238 for space power are considered and analyzed. Milliwatt-power RTGs based on plutonium-238 are completely self-contained electric power sources offering a long proven service lifetime (>15 years) and high reliability. Such electric power sources find application both for space exploration and in terrestrial equipment, especially with the advance of microsystem technologies.

Gusev, V. V.; Pustovalov, A. A.; Rybkin, N. N.; Anatychuk, L. I.; Demchuk, B. N.; Ludchak, I. Yu.

2011-05-01

96

Heat transfer design and proof tests of a radioisotope thermoelectric generator  

Microsoft Academic Search

The object was to design, build, and test the heat rejection portions of a large 2-kw(e) radioisotope thermoelectric generator (RTG). The design was optimized to produce the lowest practicable temperatures at the cold junction of a large number of thermoelectric heat-to-electricity conversion elements. The geometry was largely defined by the size, shape, and required number of thermoelectric elements and by

E. J. Beck

1974-01-01

97

A thermoelectric generator using porous si thermal isolation.  

PubMed

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

Hourdakis, Emmanouel; Nassiopoulou, Androula G

2013-10-10

98

A Novel Optimization Method for the Electric Topology of Thermoelectric Modules Used in an Automobile Exhaust Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

Based on Bi2Te3 thermoelectric modules, a kind of automobile exhaust thermoelectric generator (AETEG) with a single-column cold-source structure was designed. To enhance its net power and efficiency, the output performance of all the thermoelectric modules was tested with a temperature monitoring unit and voltage monitoring unit, and modeled using a back-propagation (BP) neural network based on various hot-source temperatures, cold-source temperatures, load currents, and contact pressures according to the temperature distribution of the designed heat exchanger and cooling system. Then, their electric topology (series or parallel hybrid) was optimized using a genetic algorithm to achieve the maximum peak power of the AETEG. From the experimental results, compared with when all the thermoelectric modules were connected only in series or parallel at random, it is concluded that the AETEG performance is evidently affected by the electric topology of all the single thermoelectric modules. The optimized AETEG output power is greatly superior to the other two investigated designs, validating the proposed optimized electric topology as both feasible and practical.

Quan, Rui; Tang, Xinfeng; Quan, Shuhai; Huang, Liang

2013-07-01

99

A Novel Optimization Method for the Electric Topology of Thermoelectric Modules Used in an Automobile Exhaust Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

Based on Bi2Te3 thermoelectric modules, a kind of automobile exhaust thermoelectric generator (AETEG) with a single-column cold-source structure was designed. To enhance its net power and efficiency, the output performance of all the thermoelectric modules was tested with a temperature monitoring unit and voltage monitoring unit, and modeled using a back-propagation (BP) neural network based on various hot-source temperatures, cold-source temperatures, load currents, and contact pressures according to the temperature distribution of the designed heat exchanger and cooling system. Then, their electric topology (series or parallel hybrid) was optimized using a genetic algorithm to achieve the maximum peak power of the AETEG. From the experimental results, compared with when all the thermoelectric modules were connected only in series or parallel at random, it is concluded that the AETEG performance is evidently affected by the electric topology of all the single thermoelectric modules. The optimized AETEG output power is greatly superior to the other two investigated designs, validating the proposed optimized electric topology as both feasible and practical.

Quan, Rui; Tang, Xinfeng; Quan, Shuhai; Huang, Liang

2012-10-01

100

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

101

A portable thermoelectric-power-generating module composed of oxide devices  

NASA Astrophysics Data System (ADS)

High power density is a strong point of thermoelectric generation. Exploitation of this salient characteristic would make thermoelectric modules promising candidates for mobile power applications. Here we show how power can be generated using a small thermoelectric module composed of 140 pairs of oxide thermoelectric unicouples. The module weighs 19.8 g and its dimensions are 53 mm long, 32 mm wide, and 5.0 mm thick. The hot-pressed thermoelectric oxide bulk materials used were connected with a Ag paste, incorporating oxide powder, and Ag electrodes. The module's open circuit voltage increases with increasing hot-side temperature (TH) and reaches 4.5 V at a TH of 1072 K in air. No deterioration in output power was seen when power generation was carried out ten times at a TH of 723 K with intermediate cooling to room temperature. The module was successfully used to charge a lithium-ion battery in a mobile phone.

Funahashi, R.; Mikami, M.; Mihara, T.; Urata, S.; Ando, N.

2006-03-01

102

Radioisotope Thermoelectric Generator Options for Pluto Fast Flyby Mission  

NASA Astrophysics Data System (ADS)

A small spacecraft design for the Pluto Fast Flyby (PFF) mission is under study by the Jet Propulsion Laboratory (PL) for the National Aeronautics and Space Administration (NASA), for a possible launch as early as 1998. JPL's 1992 baseline design calls for a power source able to furnish an energy output of 3963 kWh and a power output of 69 Watts(e) at the end of the 9.2-year mission. Satisfying those demands is made difficult because NASA management has set a goal of reducing the spacecraft mass from a baseline value of 166 kg to ~110 kg, which implies a mass goal of less than 10 kg for the power source. To support the ongoing NASA/JPL studies, the Department of Energy's Office of Special Applications (DOE/OSA) commissioned Fairchild Space to prepare and analyze conceptual designs of radioisotope power systems for the PFF mission. Thus far, a total of eight options employing essentially the same radioisotope heat source modules were designed and subjected to thermal, electrical, structural, and mass analyses by Fairchild. Five of these - employing thermoelectric converters - are described in the present paper, and three - employing free-piston Stirling converters - are described in the companion paper presented next. The system masses of the thermoelectric options ranged from 19.3 kg to 10.2 kg. In general, the options requiring least development are the heaviest, and the lighter options require more development with greater programmatic risk.

Schock, Alfred

1994-07-01

103

Effects of Fluid Directions on Heat Exchange in Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

Thermal fluids can transport heat to the large surface of a thermoelectric (TE) panel from hot and/or cold sources. The TE power thus obtainable was precisely evaluated using numerical calculations based on fluid dynamics and heat transfer. The commercial software FLUENT was coupled with a TE model for this purpose. The fluid velocity distribution and the temperature profiles in the fluids and TE modules were calculated in two-dimensional space. The electromotive force was then evaluated for counter-flow and split-flow models to show the effect of a stagnation point. Friction along the fluid surface along a long, flat path was larger than that along a short path split into two parts. The power required to circulate the fluids along the flow path is not negligible and should be considered in TE generation system design.

Suzuki, Ryosuke O.; Sasaki, Yuto; Fujisaka, Takeyuki; Chen, Min

2012-06-01

104

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

105

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

106

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

107

Development of Thermoelectric Water Heating/Cooling Devices.  

National Technical Information Service (NTIS)

A simple, safe, and reliable thermoelectric device for heating or cooling potable water for use in military vehicles was developed. the unit is capable of cooling water to 60 F in ambient temperatures up to 130 F and heating to 150 F in ambient temperatur...

B. Mathipraksam

1985-01-01

108

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

Microsoft Academic Search

Maximizing electrical energy generation through waste heat recovery is one of the modern research questions within automotive\\u000a applications of thermoelectric (TE) technologies. This paper proposes a novel concept of distributed multisection multilevel\\u000a DC–DC conversion networks based on thermoelectric generators (TEGs) for automotive applications. The concept incorporates\\u000a a bottom-up design approach to collect, convert, and manage vehicle waste heat efficiently. Several

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

2011-01-01

109

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

110

Development of a thermoelectric ice maker of fingers incorporated into a static domestic refrigerator  

Microsoft Academic Search

A domestic refrigerator wich incorporates in its interior a device to make ice cubes using thermoelectric technology has been developed. For its design a computational model has been implemented. This model solves both thermoelectric and heat transfer equations including the phase change equations. The inputs are the thermoelectric parameters as a function of the temperature and the boundary conditions: (room

J. G. Vián; D. Astrain; A. Rodríguez

111

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

112

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

PubMed

The energy conversion efficiency of today's thermoelectric generators is significantly lower than that of conventional mechanical engines. Almost all of the existing research is focused on materials to improve the conversion efficiency. Here we propose a general framework to study the cost-efficiency trade-off for thermoelectric power generation. A key factor is the optimization of thermoelectric modules together with their heat source and heat sinks. Full electrical and thermal co-optimization yield a simple analytical expression for optimum design. Based on this model, power output per unit mass can be maximized. We show that the fractional area coverage of thermoelectric elements in a module could play a significant role in reducing the cost of power generation systems. PMID:21793542

Yazawa, Kazuaki; Shakouri, Ali

2011-08-05

113

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

114

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

PubMed

The use of biomass cook stoves is widespread in the domestic sector of developing countries, but the stoves are not efficient. To advance the versatility of the cook stove, we investigated the feasibility of adding a commercial thermoelectric (TE) module made of bismuth-telluride based materials to the stove's side wall, thereby creating a thermoelectric generator system that utilizes a proportion of the stove's waste heat. The system, a biomass cook stove thermoelectric generator (BITE), consists of a commercial TE module (Taihuaxing model TEP1-1264-3.4), a metal sheet wall which acts as one side of the stove's structure and serves as the hot side of the TE module, and a rectangular fin heat sink at the cold side of the TE module. An experimental set-up was built to evaluate the conversion efficiency at various temperature ranges. The experimental set-up revealed that the electrical power output and the conversion efficiency depended on the temperature difference between the cold and hot sides of the TE module. At a temperature difference of approximately 150 degrees C, the unit achieved a power output of 2.4W. The conversion efficiency of 3.2% was enough to drive a low power incandescent light bulb or a small portable radio. A theoretical model approximated the power output at low temperature ranges. An economic analysis indicated that the payback period tends to be very short when compared with the cost of the same power supplied by batteries. Therefore, the generator design formulated here could be used in the domestic sector. The system is not intended to compete with primary power sources but serves adequately as an emergency or backup source of power. PMID:16904888

Lertsatitthanakorn, C

2006-08-14

115

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

2013-04-01

116

Thermal vacuum life test facility for radioisotope thermoelectric generators  

NASA Astrophysics Data System (ADS)

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

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

117

Optimization of the thermal regime of thermoelectric generators in waste heat recovery applications  

Microsoft Academic Search

A thermoelectric generator is a device which directly converts heat to electricity. These generators have been receiving renewed interest in a wide range of applications such as domestic wood heating, remote area power generation, automotive applications and power supply in interplanetary space flights. Applied as waste-heat recovery systems (WHRS), these generators can reduce fuel consumption and greenhouse gases such as

Jihad G. Haidar; Jamil I. Ghojel

2002-01-01

118

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

119

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

PubMed

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. PMID:21532584

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

2011-05-01

120

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

Microsoft Academic Search

The present experimental and computational study investigates a new exhaust gas waste heat recovery system for hybrid vehicles,\\u000a using a thermoelectric module (TEM) and heat pipes to produce electric power. It proposes a new thermoelectric generation\\u000a (TEG) system, working with heat pipes to produce electricity from a limited hot surface area. The current TEG system is directly\\u000a connected to the

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

2011-01-01

121

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

NASA Astrophysics Data System (ADS)

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

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

2002-01-01

122

Special Applications RTG Technology Program: Thermoelectric module development summary report  

SciTech Connect

The primary objective of the Special Applications thermoelectric module development program is to design, develop and demonstrate the performance of a module which provides a significant thermoelectric conversion efficiency improvement over available technology for low power, relatively high voltage RTGS intended for terrestrial applications. ``Low power`` can be construed as an RTG power output of 10 watts or less, and ``high voltage`` can be considered as a load voltage of 5 volts or greater. In particular, the effort is to improve the system efficiency characteristic of the state-of-the-art bismuth telluride-based RTG system (e.g., Five-Watt RTG and Half-Watt RTG), typically 3 to 4%, to the range of 6% or better. This increase in efficiency will also permit reductions in the weight and size of RTGs in the low power range.

Brittain, W.M.

1988-09-01

123

Skutterudite Thermoelectric Generator for Electrical Power Generation from Automotive Waste Heat  

NASA Astrophysics Data System (ADS)

Filled skutterudites are state-of-the- art thermoelectric (TE) materials for electrical power generation from waste heat. They have suitable intrinsic transport properties as measured by the thermoelectric figure of merit ZT = S^2?T/? (S = Seebeck coefficient, ? = electrical conductivity, T = temperature, and ? = thermal conductivity) and good mechanical strength for operation at vehicle exhaust gas temperatures of >550 C. We have demonstrated TE electrical power generation on a production test vehicle equipped with a fully functional prototype TE generator (TEG). It was assembled with TE modules fabricated from filled skutterudites synthesized at GM. Our results and analysis show that improvement in total power generated can be achieved by enhanced thermal and electrical interfaces and contacts. A substantial T decrease along the exhaust gas flow results in a large variation of voltage, current, and power output for each TE module depending on its position in the module array. Total TEG output power depends directly on the position-dependent T profile via the temperature dependence of both ZT and Carnot efficiency. Total TEG power output also depends on how the modules are connected in parallel or series combinations because mismatch in output voltage and/or internal resistance among the modules degrades the performance of the entire array. Uniform T profiles and consistent TE module internal resistances improve overall TEG performance.

Meisner, Gregory

2012-02-01

124

Thermoelectric generator placed on the human body: system modeling and energy conversion improvements  

NASA Astrophysics Data System (ADS)

This paper focuses on the production of electricity using a thermoelectric generator placed on the human body connected to a dc-dc converter. The small difference in temperature between the hot heat source (e.g. the human body, Tb = 37 °C) and the cold heat source (e.g. ambient air, Ta = 22 °C), associated with a poor quality thermal coupling (mainly with the cold source), leads to a very low temperature gradient at the thermoelectric generator terminals and hence low productivity. Under these use conditions, the present article proposes an analysis of various ways to improve productivity given a surface capture system. Furthermore, we demonstrated, in this particular context, that maximizing the recovered electric power proves to be a different problem from that of maximizing efficiency, e.g. the figure of merit Z. We therefore define a new factor ZE, depending on the physical characteristics of thermoelectric materials, that maximizes electric power in the particular case where the thermal coupling is poor. Finally, this study highlights the benefit of sub-optimization of the power extracted from the thermoelectric generator to further improve efficiency of the overall system. We show that, given the conversion efficiency of the dc-dc converter, the maximum power point of the overall system is no more reached when the output voltage of the thermoelectric generator is equal to half of its electromotive force.

Lossec, M.; Multon, B.; Ben Ahmed, H.; Goupil, C.

2010-10-01

125

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

126

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

Microsoft Academic Search

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

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

2005-01-01

127

A Digital Coreless Maximum Power Point Tracking Circuit for Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

This paper describes a maximum power point tracking (MPPT) circuit for thermoelectric generators (TEG) without a digital controller unit. The proposed method uses an analog tracking circuit that samples the half point of the open-circuit voltage without a digital signal processor (DSP) or microcontroller unit for calculating the peak power point using iterative methods. The simulation results revealed that the MPPT circuit, which employs a boost-cascaded-with-buck converter, handled rapid variation of temperature and abrupt changes of load current; this method enables stable operation with high power transfer efficiency. The proposed MPPT technique is a useful analog MPPT solution for thermoelectric generators.

Kim, Shiho; Cho, Sungkyu; Kim, Namjae; Baatar, Nyambayar; Kwon, Jangwoo

2011-05-01

128

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)

1998-01-01

129

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

130

Exhaust gas bypass valve control for thermoelectric generator  

SciTech Connect

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

131

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

132

The General-Purpose Heat Source Radioisotope Thermoelectric Generator: A Truly General-Purpose Space RTG  

NASA Astrophysics Data System (ADS)

The General-Purpose Heat Source Radioisotope Thermoelectric Generator (GPHS-RTG) was developed for the originally planned International Solar Polar Mission (ISPM). [ISPM would later, with the elimination of the NASA spacecraft, become the Ulysses mission.] At 300 We beginning-of-life (BOL) power, the GPHS-RTG was the most powerful RTG with the highest specific power (5.3 We/kg) of any space RTG. These improved performance attributes of the GPHS-RTG made it attractive for use on the Galileo mission. Subsequently, the GPHS-RTG was selected to power the Cassini spacecraft, which is currently orbiting Saturn, and the New Horizons spacecraft which is on its way to Pluto. Truly, the GPHS-RTG is a ``general-purpose'' space RTG.

Bennett, Gary L.; Lombardo, James J.; Hemler, Richard J.; Silverman, Gil; Whitmore, C. W.; Amos, Wayne R.; Johnson, E. W.; Zocher, Roy W.; Hagan, James C.; Englehart, Richard W.

2008-01-01

133

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

134

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

135

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

PubMed

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

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

2013-09-16

136

A Four-Quadrant Operation Diagram for Thermoelectric Modules in Heating-Cooling Mode and Generating Mode  

NASA Astrophysics Data System (ADS)

The operation of a thermoelectric module in heating-cooling mode, generating mode, and regenerating mode can be discussed in terms of power, cooling load, and current. A direct current machine in motoring mode and generating mode and an induction motor in motoring mode and regenerating mode are analogous to thermoelectric modules. Therefore, the first objective of this work is to present the four-quadrant (4-Q) operation diagram and the 4-Q equivalent circuits of thermoelectric modules in heating-cooling mode and generating mode. The second objective is to present the cooling and regenerating curves of a thermoelectric module in cooling mode and regenerating mode. The curves are composed from the cooling powers and the generating powers, the input and output current, the thermal resistance of the heat exchanger, and the different temperatures that exist between the hot and cold sides of the thermoelectric module. The methodology used to present the data involved drawing analogies between the mechanical system, the electrical system, and the thermal system; an experimental setup was also used. The experimental setup was built to test a thermoelectric module (TE2) in cooling mode and regenerating mode under conditions in which it was necessary to control the different temperatures on the hot and cold sides of TE2. Two thermoelectric modules were used to control the temperature. The cold side was controlled by a thermoelectric module labeled TE1, whereas the hot side was controlled by a second thermoelectric module labeled TE3. The results include the power, the cooling load, and the current of the thermoelectric module, which are analogous to the torque, the power, the speed, and the slip speed of a direct current machine and an induction motor. This 4-Q operation diagram, the 4-Q equivalent circuits, and the cooling and regenerating curves of the thermoelectric module can be used to analyze the bidirectional current and to select appropriate operating conditions in the cooling and regenerating modes.

Chimchavee, W.

2011-05-01

137

Thermoelectric generator placed on the human body: system modeling and energy conversion improvements  

Microsoft Academic Search

This paper focuses on the production of electricity using a thermoelectric generator placed on the human body connected to a dc-dc converter. The small difference in temperature between the hot heat source (e.g. the human body, Tb = 37 °C) and the cold heat source (e.g. ambient air, Ta = 22 °C), associated with a poor quality thermal coupling (mainly

M. Lossec; B. Multon; H. Ben Ahmed; C. Goupil

2010-01-01

138

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

139

[Radioisotope thermoelectric generators and ancillary activities]. Monthly technical progress report, 1 April--28 April 1996  

SciTech Connect

Tehnical progress achieved during this period on radioisotope thermoelectric generators is described under the following tasks: engineering support, safety analysis, qualified unicouple fabrication, ETG fabrication/assembly/test, RTG shipping/launch support, design/review/mission applications, and project management/quality assurance/reliability.

NONE

1996-06-01

140

Analysis of heat losses and ways to improve the efficiency of solar-array thermoelectric generators  

Microsoft Academic Search

Ways to improve the efficiency of solar thermoelectric generators by reducing heat losses are discussed. Different heat transfer conditions are examined: single and double layer glass coatings, selective coatings on the collector, ordinary and vacuum-type heat insulation, and air and water cooling.

I. I. Kokhova; Iu. N. Malevskii; A. I. Tsvetkov

1980-01-01

141

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

142

Liquid Hydrocarbon-Fueled Thermo-Electric Generator with Counter-Flow Type Regenerative Heat Exchanger.  

National Technical Information Service (NTIS)

An air-to-air heat exchanger, comprising an array of stainless steel tubings arranged in a three-fold pass, is connected to the outlet of the combustion chamber of a liquid hydrocarbon-fueled, thermoelectric generator. Air enters the heat exchanger at the...

G. Guazzoni A. Herchakowski

1980-01-01

143

Clean Diesel Engine Component Improvement Program. Diesel Truck Thermoelectric Generator.  

National Technical Information Service (NTIS)

Hi-Z Technology, Inc. (Hi-Z) is currently developing four different auxiliary generator designs that are used to convert a portion (5 to 20%) of the waste heat from vehicle engines exhaust directly to electricity. The four designs range from 200 Watts to ...

A. Kushch D. Krommenhoek D. Snowden J. C. Bass N. B. Elsner S. Ghamaty S. Marchetti

2005-01-01

144

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

145

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

2013-04-01

146

Oxide-based thermoelectric power generation module using p-type Ca 3Co 4O 9 and n-type (ZnO) 7In 2O 3 legs  

Microsoft Academic Search

This study presents the fabrication of an oxide-based thermoelectric power generation module using layer-structured p-type Ca3Co4O9 and n-type (ZnO)7In2O3 legs. The potential for development and effective use of high power density thermoelectric generation system is investigated in terms of its power per area, the temperature conditions, and the number of p–n couples. The significance of the manufacturing factors including contact

Soon-Mok Choi; Kyu-Hyoung Lee; Chang-Hyun Lim; Won-Seon Seo

2011-01-01

147

Recent developments in nanostructured thermoelectric materials and devices  

Microsoft Academic Search

Thermal management is a critical issue for microelectronic and microphotonic devices. The efficiency of actual thermoelectric devices is determined by the thermoelectric figure of merit Z. Because Z has unit of inverse temperature, nondimensional figure-of-merit ZT that appears often in device analysis is commonly used. The best ZT materials are found in heavily doped semiconductors which has ZT ? 1.

Ronggui Yang; Gang Chen

2004-01-01

148

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

SciTech Connect

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

David Feldman; Amanda Slough; Gary Garrett

2008-06-01

149

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

SciTech Connect

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

Becker, D.L.

1997-05-01

150

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

151

Quality Assurance Plan for Heat Source\\/Radioisotope Thermoelectric Generator Programs  

Microsoft Academic Search

The purpose of this document is to serve as the Quality Assurance Plan for Heat Source\\/Radioisotope Thermoelectric Generator (HS\\/RTG) programs performed at EG&G Mound Applied Technologies. As such, it identifies and describes the systems and activities in place to support the requirements contained in DOE Order 5700.6C as reflected in MD-10334, Mound Quality Policy and Responsibilities and the DOE\\/RPSD supplement,

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

1995-01-01

152

Liquid hydrocarbon-fueled thermo-electric generator with counter-flow type regenerative heat exchanger  

Microsoft Academic Search

An air-to-air heat exchanger, comprising an array of stainless steel tubings arranged in a three-fold pass, is connected to the outlet of the combustion chamber of a liquid hydrocarbon-fueled, thermoelectric generator. Air enters the heat exchanger at the ambient temperature and is pre-heated up to 500°C at the same time, the temperature of the gases leaving the combustion chamber is

G. Guazzoni; A. Herchakowski

1980-01-01

153

Analysis of thermoelectric water use in the United States  

NASA Astrophysics Data System (ADS)

Compared with many other countries, the United States is relatively well endowed with water resources. Despite this abundance, water adequacy has emerged as one of America's primary resource issues. Thermoelectric power generation is the largest offstream water user in the United States. In spite of its large amount of water use and other associated adverse environmental impacts, fewer water use studies have been conducted for thermoelectric generation than for other water use sectors. Consequently, there is little understanding of the determinants of thermoelectric water use and the magnitude of their effects on water usage rates. The major objective of this study is to identify the main determinants of thermoelectric water use and quantify their impacts using multiple regression techniques. Multiple regression models have been developed at two levels: state level and plant level. State level thermoelectric water use data were obtained from the U.S. Geological Survey. The agency has been collecting state-level thermoelectric water use since 1960 at a five-year interval. Plant level thermoelectric water use data were obtained from the Department of Energy that has been conducting surveys on steam thermoelectric power plant operations including their water uses. Models on both thermoelectric withdrawals and consumptive use have been developed. The developed models have shown that thermoelectricity generation, types of cooling facilities, fuel types, generation types, operation conditions, and water sources can significantly influence the amount of thermoelectric water use. The developed thermoelectric water use models are used to forecast future thermoelectric withdrawals. The models predict increases of more than 25 bgd in thermoelectric withdrawals between 2000 and 2025, even when the national average unit thermoelectric withdrawals are projected to continue decreasing from 25.7 gallons/KWh in 1995 to 16.6 gallons/KWh in 2025. The main reason for this is the National Energy Modeling System (NEMS)'s projections of large increase in thermoelectricity generation from 2694.4 BKWh in 1995 to 5073.5 BKWh in 2025. However, analysis of thermoelectric water use has revealed much variability in unit thermoelectric withdrawals in each type of power plant. The potential to increase water use efficiency in thermoelectric power generation may reverse the trend of increases in thermoelectric withdrawals.

Yang, Xiaoying

154

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

155

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

2012-11-05

156

Power flattening techniques for radioisotopic thermoelectric generators. Interim report 1 December 1983-16 March 1984  

SciTech Connect

The objective of this program is the investigation of a novel means of reducing the potential ecologic hazards that may be associated with radioisotopic thermoelectric generators (RTG's). A number of short lived isotopes have lower toxicities and are more ecologically acceptable than the Plutonium 238 used at present. In addition, the shorter half lives significantly reduce the time period during which isotope encapsulation must be assured (approx. 10 half lives). The technical approach involves the use of a gas controlled heat pipe to maintain a nearly constant heat input to the thermoelectric converter in spite of the decay profile of a short live heat pipe-RTG system is expected to operate over at least two isotope half lives (4:1 turndown ratio), supplying a thermoelectric module with the heat required to generate one watt of electricity. The end product of the program is a proof of principle heat pipe demonstrating the desired heat transport and turndown capability. The program has three items of work: Survey of Technology Base; Design of Proof of Principle Heat Pipe; Heat Pipe Fabrication and Test.

Eastman, G.Y.

1984-03-11

157

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

158

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

NASA Astrophysics Data System (ADS)

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

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

1983-04-01

159

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

160

Development of a thermoelectric refrigerator with two-phase thermosyphons and capillary lift  

Microsoft Academic Search

A thermoelectric domestic refrigerator has been developed, with a single compartment of 0.225m3, for food preservation at 5°C. The cooling system is made up of two equal thermoelectric devices, each composed of a Peltier module (50W) with its hot side in contact with a two-phase and natural convection thermosyphon (TSV) and a two-phase and capillary lift thermosyphon (TPM), in contact

J. G. Vián; D. Astrain

2009-01-01

161

Radioisotope thermoelectric generator licensed hardware package and certification tests  

Microsoft Academic Search

This paper presents the Licensed Hardware package and the Certification Test portions of the Radioisitope Themoelectric Generator Transportation System. This package has been designed to meet those portions of the Code of Federal Regulations (10 CFR 71) relating to ‘‘Type B’’ shipments of radioactive materials. The licensed hardware is now in the U. S. Department of Energy licensing process that

Louis H. Goldmann; Henry S. Averette

1995-01-01

162

Energy harvesting thermoelectric generators manufactured using the complementary metal oxide semiconductor process.  

PubMed

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 mW at a temperature difference of 15 K. PMID:23396193

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

2013-02-08

163

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

164

Polyimide/PDMS flexible thermoelectric generator for ambient assisted living applications  

NASA Astrophysics Data System (ADS)

Present work proposed design, finite element tools simulation and prototype fabrication of a low cost energy autonomous, maintenance free, flexible and wearable micro thermoelectric generator (?TEG), finalized to power very low consumption electronics Ambient Assisted Living (AAL) applications. The prototype, integrating an array of 100 thin films thermocouples of Sb2Te3 and Bi2Te3, generates, at 40 °C, an open circuit output voltage of 430 mV and an electrical output power up to 32 nW with matched load. In real operation conditions of prototype, which are believed to be very close to a thermal gradient of 15°C, the device generates an open circuit output voltage of about 160 mV, with an electrical output power up to 4.18 nW. In this work we proposed design, thermal simulation and fabrication of a preliminary flexible and wearable micro thermoelectric generator (?TEG), finalized to power very low consumption electronics for Ambient Assisted Living (AAL) applications. Presented simulations show the performances of different fabrication solution for the PDMS/Kapton packages, considering flat and sloped walls approach for thermal gradient enhancement.

Francioso, L.; de Pascali, C.; Farella, I.; Martucci, C.; Cretì, P.; Siciliano, P.

2011-05-01

165

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

166

(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

167

Environmental assessment of decommissioning radioisotope thermoelectric generators (RTG) in northwest Russia  

SciTech Connect

This article presents some results from assessment work conducted as part of a joint Norwegian-Russian project to decommission radioisotope thermoelectric generators (RTG) in Northwest Russia. Potential worst case accident scenarios, based on the decommissioning procedures for RTGs, were assessed to study possible radiation effects to the environment. Close contact with exposed RTG sources will result in detrimental health effects. However, doses to marine biota from ingestion of radioactivity under the worst-case marine scenario studied were lower than threshold limits given in IAEA literature. (authors)

Hosseini, A.; Standring, W.J.F.; Brown, J.E.; Dowdall, M.; Amundsen, I.B. [Norwegian Radiation Protection Authority, PO Box 55, N-1332 Oesteraes (Norway)

2007-07-01

168

Radioisotope Thermoelectric Generator Package O-Ring Seal Material Validation Testing  

SciTech Connect

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 (1) 233 K ({minus}40 {degrees}F), (2) a specified operating temperature, and (3) 244 K ({minus}20 {degrees}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, H.E.; Ferrell, P.C.; Knight, R.C.

1994-09-30

169

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

170

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

2013-10-01

171

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

172

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

173

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

174

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

175

Thermoelectric converter modeling in nuclear space power conversion and regulation  

Microsoft Academic Search

Thermoelectric converters are being used on low power planetary spacecraft. The same type of conversion was considered for Ground Engineering System development of nuclear power generation under the SP-100 program for high power earth orbiting spacecraft. Here, the baseline design is aimed at generating power, using a nuclear reactor to produce heat, a thermoelectric converter to produce electricity, a power

S. R. Yadavalli

1986-01-01

176

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

177

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

178

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

179

Device for use in a furnace exhaust stream for thermoelectric generation  

DOEpatents

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

Polcyn, Adam D.

2013-06-11

180

Radioisotope Thermoelectric Generator Transporation System licensed hardware second certification test series and package shock mount system test  

Microsoft Academic Search

This paper presents a summary of two separate drop test a e performed in support of the Radioisotope Thermoelectric Generator (RTG) Transportation System (RTGTS). The first portion of this paper presents the second series of drop testing required to demonstrate that the RTG package design meets the requirements of Title 10, Code of Federal Regulations, ``Part 71`` (10 CFR 71).

P. C. Ferrell; D. A. Moody

1995-01-01

181

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

182

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

183

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

184

Quality Assurance Plan for Heat Source/Radioisotope Thermoelectric Generator Programs  

SciTech Connect

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

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

1995-03-16

185

Radioisotope thermoelectric generator package o-ring seal material validation testing  

SciTech Connect

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 ({minus}40 {degree}F), (2) a specified operating temperature, and (3) 244 K ({minus}20 {degree}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. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}

Adkins, H.E.; Ferrell, P.C.; Knight, R.C. [Westinghouse Hanford Company, P. O. Box 1970, MSIN N1-25, Richland, Washington 99352 (United States)

1995-01-20

186

High-temperature thermoelectric transport at small scales: Thermal generation, transport and recombination of minority carriers  

PubMed Central

Thermoelectric transport in semiconductors is usually considered under small thermal gradients and when it is dominated by the role of the majority carriers. Not much is known about effects that arise under the large thermal gradients that can be established in high-temperature, small-scale electronic devices. Here, we report a surprisingly large asymmetry in self-heating of symmetric highly doped silicon microwires with the hottest region shifted along the direction of minority carrier flow. We show that at sufficiently high temperatures and strong thermal gradients (~1?K/nm), energy transport by generation, transport and recombination of minority carriers along these structures becomes very significant and overcomes convective energy transport by majority carriers in the opposite direction. These results are important for high-temperature nanoelectronics such as emerging phase-change memory devices which also employ highly doped semiconducting materials and in which local temperatures reach ~1000?K and thermal gradients reach ~10–100?K/nm.

Bakan, Gokhan; Khan, Niaz; Silva, Helena; Gokirmak, Ali

2013-01-01

187

Development and experimental validation of a computational model in order to simulate ice cube production in a thermoelectric ice-maker  

Microsoft Academic Search

We have developed a computational model which allows the simulation of a thermoelectric device to make ice cubes in a vapour compression domestic fridge. This model solves both the thermoelectric and heat transfer equations, including the phase change equations in the ice cube production.The inputs of the model are: the thermoelectric parameters as a function of the temperature; dimensions; material

A. Rodríguez; J. G. Vián; D. Astrain

2009-01-01

188

Design and operation of an inert gas facility for thermoelectric generator storage  

SciTech Connect

While the flight hardware is protected by design from the harsh environments of space, its in-air storage often requires special protection from contaminants such as dust, moisture and other gases. One of these components, the radioisotope thermoelectric generator (RTG) which powers the missions, was deemed particularly vulnerable to pre-launch aging because the generators remain operational at core temperatures in excess of 1000 degrees centigrade throughout the storage period. Any oxygen permitted to enter the devices will react with thermally hot components, preferentially with molybdenum in the insulating foils, and with graphites to form CO/CO{sub 2} gases which are corrosive to the thermopile. It was important therefore to minimize the amount of oxygen which could enter, by either limiting the effective in-leakage areas on the generators themselves, or by reducing the relative amount of oxygen within the environment around the generators, or both. With the generators already assembled and procedures in place to assure minimal in-leakage in handling, the approach of choice was to provide a storage environment which contains significantly less oxygen than normal air. 2 refs.

Goebel, C.J.

1990-01-01

189

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

Microsoft Academic Search

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

S. Maneewan; B. Zeghmati

2007-01-01

190

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

SciTech Connect

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

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

2006-10-01

191

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

192

A 42-V Electrical and Hybrid Driving System Based on a Vehicular Waste-Heat Thermoelectric Generator  

NASA Astrophysics Data System (ADS)

A 42-V powernet has been recognized as the next generation of vehicle electrical systems, and the waste-heat thermoelectric generator is becoming the future of vehicular energy conservation and emission reduction technologies. In this paper, effective utilization of vehicular waste-heat energy is proposed by introducing an electrical and hybrid driving system, which is an assemblage of a waste-heat thermoelectric generator, a 42-V powernet, and an integrated starter and generator (ISG). A vehicle model and the submodels for the new system have been built on the ADVISOR platform based on MATLAB/Simulink, and the dynamic performance of the vehicle model tested using the Economic Commission for Europe-Europe Urban Dynamometer Cycle driving cycle. The simulation results indicate that application of a 42-V waste-heat thermoelectric vehicle could be an integrated approach for fuel economy improvement and emission reduction, compared with a conventional internal combustion engine vehicle and an ISG-type 42-V vehicle.

Deng, Y. D.; Fan, W.; Ling, K.; Su, C. Q.

2012-06-01

193

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

2013-10-01

194

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

2013-07-05

195

POTENTIAL THERMOELECTRIC APPLICATIONS IN DIESEL VEHICLES  

SciTech Connect

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

Crane, D

2003-08-24

196

Subsea thermoelectric generators. 1- 10-watt peltier effect prototypes - a step towards autonomous electrical control units at subsea wellheads  

SciTech Connect

Offshore oil production activities require the operation of underwater hydraulic or electric equipment. The high cost of acquisition and installation of umbilical cables to supply power is leading to the development of independently powered cableless equipment, connected to the surface by the transmission and reception of control signals through the water. As a first step toward these autonomous wellhead control systems, the authors designed and successfully tested in laboratory conditions a thermoelectric generator able to supply at least 10 watts of electric power, extracting it from the temperature difference between the oil and the surrounding water. Hydraulic pumps and pressure accumulators, control electronics, and valve actuators for wellhead control units are all technically solved problems, even for seafloors as deep as 1,000 meters. However, an autonomous underwater wellhead control unit can only be conceived if an energy source is available at the seafloor. The development of a reliable and compact power source is indeed a fundamental step towards autonomous wet Christmas tree valve actuators.

Weid, J.P. von der; Silva, J.A.P. da; Gama, A.L.; Sant'Anna, A.C.

1994-05-01

197

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

SciTech Connect

Solar energy is one of the most promising energy resources on Earth and in space, because it is clean and inexhaustible. Therefore, we have been developing a solar-powered high-efficiency thermionic-thermoelectric conversion system which combines a thermionic converter (TIC) with a thermoelectric converter (TEC) to use thermal energy efficiently and to achieve high efficiency conversion. The TIC emitter must uniformly heat up to 1800 K. The TIC emitter can be heated using thermal radiation from a solar receiver maintained at a high temperature by concentrated solar irradiation. A cylindrical cavity-type solar receiver constructed from graphite was designed and heated in a vacuum by using the solar concentrator at Tohoku University. The maximum temperature of the solar receiver enclosed by a molybdenum cup reached 1965 K, which was sufficiently high to heat a TIC emitter using thermal radiation from the receiver. 4 refs., 6 figs., 1 tab.

Naito, H.; Kohsaka, Y.; Cooke, D.; Arashi, H. [Tohoku Univ., Aramaki (Japan)

1996-10-01

198

High-temperature thermoelectric transport at small scales: Thermal generation, transport and recombination of minority carriers.  

PubMed

Thermoelectric transport in semiconductors is usually considered under small thermal gradients and when it is dominated by the role of the majority carriers. Not much is known about effects that arise under the large thermal gradients that can be established in high-temperature, small-scale electronic devices. Here, we report a surprisingly large asymmetry in self-heating of symmetric highly doped silicon microwires with the hottest region shifted along the direction of minority carrier flow. We show that at sufficiently high temperatures and strong thermal gradients (~1?K/nm), energy transport by generation, transport and recombination of minority carriers along these structures becomes very significant and overcomes convective energy transport by majority carriers in the opposite direction. These results are important for high-temperature nanoelectronics such as emerging phase-change memory devices which also employ highly doped semiconducting materials and in which local temperatures reach ~1000?K and thermal gradients reach ~10-100?K/nm. PMID:24056703

Bakan, Gokhan; Khan, Niaz; Silva, Helena; Gokirmak, Ali

2013-09-23

199

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

200

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

201

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

SciTech Connect

In October 1989, a US shuttle lifted off from Cape Kennedy carrying the spacecraft Galileo on its mission to Jupiter. In November 1990, a second spacecraft, Ulysses, will be launched from Cape Kennedy with a mission to study the polar regions of the sun. The prime source of power for both spacecraft is a series of radioisotope thermoelectric generators (RTGs), which use plutonium oxide (plutonia) as a heat source. Several of the key components in this power system are required to ensure the safety of both the public and the environment and were manufactured at Oak Ridge National Laboratory (ORNL) in the 1980 to 1983 period. For these two missions, Martin Marietta Energy Systems, Inc. (Energy Systems), will provide an iridium-alloy component used to contain the plutonia heat source and a carbon-composite material that serves as a thermal insulator. ORNL alone will continue to fabricate the carbon-composite material. Because of the importance to DOE that Energy Systems deliver these high-quality components on time, performance of an Operational Readiness Review (ORR) of these manufacturing activities is necessary. Energy Systems Policy GP-24 entitled Operational Readiness Process'' describes the formal and comprehensive process by which appropriate Energy Systems activities are to be reviewed to ensure their readiness. This Energy System policy is aimed at reducing the risks associated with mission success and requires a management-approved readiness plan'' to be issued. This document is the readiness plan for the RTG materials production tasks. 6 refs., 11 figs., 1 tab.

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

1990-04-19

202

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

SciTech Connect

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

Lockwood, A.; Shields, V.

1980-07-01

203

A New Test Rig for Accurate Nonparametric Measurement and Characterization of Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

Thermoelectric generators (TEGs) are increasingly employed in large-scale applications, therefore accurate performance data are necessary to permit precise designs and simulations. However, there is still no standardized method to test the electrical and thermal performance of TEGs. This paper presents an innovative test system to assess device performance in the "real world." The fixture allows the hot temperature to be increased up to 800°C with minimal thermal losses and thermal shock; the clamping load can be adjusted up to 5 kN, and the temperatures are sensed by thermocouples placed directly on the TEG's surfaces. A computer program controls all the instruments in order to minimize errors and to aid accurate measurement and test repeatability. The test rig can measure four TEGs simultaneously, each one individually controlled and heated by a maximum electrical power of 2 kW. This allows testing of the effects of series and parallel connection of TEGs under mismatched conditions, e.g., dimensions, clamping force, temperature, etc. The test rig can be employed both as a performance evaluator and as a quality control unit, due to the ability to provide nonparametric testing of four TEGs concurrently. It can also be used to rapidly characterize devices of different dimensions at the same time.

Montecucco, Andrea; Buckle, James; Siviter, Jonathan; Knox, Andrew R.

2013-03-01

204

A New Test Rig for Accurate Nonparametric Measurement and Characterization of Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

Thermoelectric generators (TEGs) are increasingly employed in large-scale applications, therefore accurate performance data are necessary to permit precise designs and simulations. However, there is still no standardized method to test the electrical and thermal performance of TEGs. This paper presents an innovative test system to assess device performance in the "real world." The fixture allows the hot temperature to be increased up to 800°C with minimal thermal losses and thermal shock; the clamping load can be adjusted up to 5 kN, and the temperatures are sensed by thermocouples placed directly on the TEG's surfaces. A computer program controls all the instruments in order to minimize errors and to aid accurate measurement and test repeatability. The test rig can measure four TEGs simultaneously, each one individually controlled and heated by a maximum electrical power of 2 kW. This allows testing of the effects of series and parallel connection of TEGs under mismatched conditions, e.g., dimensions, clamping force, temperature, etc. The test rig can be employed both as a performance evaluator and as a quality control unit, due to the ability to provide nonparametric testing of four TEGs concurrently. It can also be used to rapidly characterize devices of different dimensions at the same time.

Montecucco, Andrea; Buckle, James; Siviter, Jonathan; Knox, Andrew R.

2013-07-01

205

Thermoelectric converter  

DOEpatents

This invention relates in general to thermoelectric units and more particularly to a tubular thermoelectric unit which includes an array of tandemly arranged radially tapered annular thermoelectric pellets having insulation material of a lower density than the thermoelectric pellets positioned between each pellet. (Official Gazette)

Kim, C.K.

1974-02-26

206

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

207

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...

208

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

209

KOVEC studies of radioisotope thermoelectric generator response (In connection with possible NASA space shuttle accident explosion scenarios)  

SciTech Connect

The Department of Energy (DOE) commissioned a study leading to a final report (NUS-4543, Report of the Shuttle Transportation System (STS) Explosion Working Group (EWG), June 8, 1984), concerned with PuO/sub 2/ dispersal should the NASA space shuttle explode during the proposed Galileo and ISPN launches planned for 1986. At DOE's request, LLNL furnished appendices that describe hydrocode KOVEC calculations of potential damage to the Radioisotope Thermoelectric Generators, fueled by PuO/sub 2/, should certain explosion scenarios occur. These appendices are contained in this report.

Walton, J.; Weston, A.; Lee, E.

1984-06-26

210

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

211

Energy and environmental optimization in thermoelectrical generating processes—application of a carbon dioxide capture system  

Microsoft Academic Search

Increased thermodynamic efficiency coupled with reduced impact on the environment are fundamental aims in the generation and rational use of energy if a contribution is to be made towards sustainable development on both a local and worldwide scale. Technological developments over recent years in the field of thermal electricity generation, together with research and technologies emerging from environmentally friendly systems,

Ismael García; J. V. M Zorraquino

2002-01-01

212

High Temperature Integrated Thermoelectric Ststem and Materials  

SciTech Connect

The final goal of this project is to produce, by the end of Phase II, an all ceramic high temperature thermoelectric module. Such a module design integrates oxide ceramic n-type, oxide ceramic p-type materials as thermoelectric legs and oxide ceramic conductive material as metalizing connection between n-type and p-type legs. The benefits of this all ceramic module are that it can function at higher temperatures (> 700 C), it is mechanically and functionally more reliable and it can be scaled up to production at lower cost. With this all ceramic module, millions of dollars in savings or in new opportunities recovering waste heat from high temperature processes could be made available. A very attractive application will be to convert exhaust heat from a vehicle to reusable electric energy by a thermoelectric generator (TEG). Phase I activities were focused on evaluating potential n-type and p-type oxide compositions as the thermoelectric legs. More than 40 oxide ceramic powder compositions were made and studied in the laboratory. The compositions were divided into 6 groups representing different material systems. Basic ceramic properties and thermoelectric properties of discs sintered from these powders were measured. Powders with different particles sizes were made to evaluate the effects of particle size reduction on thermoelectric properties. Several powders were submitted to a leading thermoelectric company for complete thermoelectric evaluation. Initial evaluation showed that when samples were sintered by conventional method, they had reasonable values of Seebeck coefficient but very low values of electrical conductivity. Therefore, their power factors (PF) and figure of merits (ZT) were too low to be useful for high temperature thermoelectric applications. An unconventional sintering method, Spark Plasma Sintering (SPS) was determined to produce better thermoelectric properties. Particle size reduction of powders also was found to have some positive benefits. Two composition systems, specifically 1.0 SrO - 0.8 x 1.03 TiO2 - 0.2 x 1.03 NbO2.5 and 0.97 TiO2 - 0.03 NbO2.5, have been identified as good base line compositions for n-type thermoelectric compositions in future module design. Tests of these materials at an outside company were promising using that company's processing and material expertise. There was no unique p-type thermoelectric compositions identified in phase I work other than several current cobaltite materials. Ca3Co4O9 will be the primary p-type material for the future module design until alternative materials are developed. BaTiO3 and rare earth titanate based dielectric compositions show both p-type and n-type behavior even though their electrical conductivities were very low. Further research and development of these materials for thermoelectric applications is planned in the future. A preliminary modeling and optimization of a thermoelectric generator (TEG) that uses the n-type 1.0 SrO - 1.03 x 0.8 TiO2 - 1.03 x 0.2 NbO2.5 was performed. Future work will combine development of ceramic powders and manufacturing expertise at TAM, development of SPS at TAM or a partner organization, and thermoelectric material/module testing, modeling, optimization, production at several partner organizations.

Mike S. H. Chu

2011-06-06

213

MeV Si ion beam modification effects on the thermoelectric generator from Er 0.1Fe 1.9SbGe 0.4 thin film  

Microsoft Academic Search

Effective thermoelectric materials and devices have a low thermal conductivity and a high electrical conductivity. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT. The purpose of this study is to improve the figure of merit of the single layer of Er0.1Fe1.9SbGe0.4 thin film used as thermoelectric generators. We have deposited the

S. Budak; S. Guner; C. Muntele; D. Ila

2009-01-01

214

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

215

Thermoelectric power conversion in space  

SciTech Connect

This paper discusses how thermoelectric power conversion systems have a broad potential for applicability to a large number of different classes of space missions. As research continues on thermoelectric materials, the potential for significantly improved performance is good. With research also occurring in the power conversion field to improve configurations and specific designs, thermoelectric power conversion continues to show great promise for near- and long-term space missions. The next generation of radioisotope thermoelectric generators will use a radiatively heated multicouple that incorporates 20 individual couples within a single cell.

Awaya, H.I.; Ewell, R.; Nesmith, B.; Vandersande, J. (Jet Propulsion Lab., California Institute of Technology, Pasadena, CA (US))

1990-09-01

216

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

217

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

SciTech Connect

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

None

2012-01-31

218

Thermoelectric harvesting of low temperature natural/waste heat  

NASA Astrophysics Data System (ADS)

Apart from specialized space requirements current development in applications of thermoelectric generation mainly relate to reducing harmful carbon emissions and decreasing costly fuel consumption through the recovery of exhaust heat from fossil fuel powered engines and emissions from industrial utilities. Focus on these applications is to the detriment of the wider exploitations of thermoelectrics with other sources of heat energy, and in particular natural occurring and waste low temperature heat, receiving little, if any, attention. In this presentation thermoelectric generation applications, both potential and real in harvesting low temperature waste/natural heat are reviewed. The use of thermoelectrics to harvest solar energy, ocean thermal energy, geothermal heat and waste heat are discussed and their credibility as future large-scale sources of electrical power assessed.

Rowe, David Michael

2012-06-01

219

Advanced Thermoelectric Materials for Efficient Waste Heat Recovery in Process Industries  

SciTech Connect

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

Adam Polcyn; Moe Khaleel

2009-01-06

220

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

221

Multilayer thermoelectric films: A strategy for the enhancement of ZT  

SciTech Connect

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

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

1995-03-01

222

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

223

Nano-Engineered Thermoelectric Coating.  

National Technical Information Service (NTIS)

A nano-engineering approach has been developed for the synthesis of the thermoelectric composite materials. A possible way for enhancing ZT is to incorporate thermoelectric materials, e.g., Skutterudite, into the nano-sized pores of three-dimensional peri...

M. Toprak Y. Zhang M. Muhammed

2000-01-01

224

Thermoelectric energy conversion using nanostructured materials  

NASA Astrophysics Data System (ADS)

High performance thermoelectric materials in a wide range of temperatures are essential to broaden the application spectrum of thermoelectric devices. This paper presents experiments on the power and efficiency characteristics of lowand mid-temperature thermoelectric materials. We show that as long as an appreciable temperature difference can be created over a short thermoelectric leg, good power output can be achieved. For a mid-temperature n-type doped skutterudite material an efficiency of over 11% at a temperature difference of 600 °C could be achieved. Besides the improvement of thermoelectric materials, device optimization is a crucial factor for efficient heat-to-electric power conversion and one of the key challenges is how to create a large temperature across a thermoelectric generator especially in the case of a dilute incident heat flux. For the solar application of thermoelectrics we investigated the concept of large thermal heat flux concentration to optimize the operating temperature for highest solar thermoelectric generator efficiency. A solar-to-electric power conversion efficiency of ~5% could be demonstrated. Solar thermoelectric generators with a large thermal concentration which minimizes the amount of thermoelectric nanostrucutured bulk material shows great potential to enable cost-effective electrical power generation from the sun.

Chen, Gang; Kraemer, Daniel; Muto, Andrew; McEnaney, Kenneth; Feng, Hsien-Ping; Liu, Wei-Shu; Zhang, Qian; Yu, Bo; Ren, Zhifeng

2011-05-01

225

Thermoelectric material development. Quarterly technical progress report, January 1, 1995--March 31, 1995  

SciTech Connect

We have found that there is a limited range of solid solutions between the skutterudite compounds CoSb{sub 3} and RuSb{sub 2}Te (about 5% on each side). For the system (RuSb{sub 2}Te){sub x}(CoSb{sub 3}){sub 1-x}, preliminary results obtained on one n-type sample on the CoSb{sub 3}-rich side show that these alloys have good thermoelectric properties and a maximum ZT of about 0.89 was obtained at about 600 C. More experiments will be started to investigate the possibility of a broader range of miscibility in this system which would allow an even further decrease in the lattice thermal conductivity, resulting in better thermoelectric properties. IrSb{sub 3} and RuSb{sub 2}Te form a complete range of solid solutions. Hot-pressed samples in this system have shown p-type conductivity. The thermoelectric properties of these p-type alloys have been measured and results have shown that their potential for thermoelectric applications is limited mainly because of the relatively low Seebeck coefficient values for p-type materials. Efforts will be directed on preparing n-type samples of the same alloys by doping with various dopants such as Ni and Pd.

Vandersande, J.W.; Caillat, T.

1995-07-01

226

TOPICAL REVIEW: Development of novel thermoelectric materials by reduction of lattice thermal conductivity  

NASA Astrophysics Data System (ADS)

Thermal conductivity is one of the key parameters in the figure of merit of thermoelectric materials. Over the past decade, most progress in thermoelectric materials has been made by reducing their thermal conductivity while preserving their electrical properties. The phonon scattering mechanisms involved in these strategies are reviewed here and divided into three groups, including (i) disorder or distortion of unit cells, (ii) resonant scattering by localized rattling atoms and (iii) interface scattering. In addition, we propose construction of a 'natural superlattice' in thermoelectric materials by intercalating an MX layer into the van der Waals gap of a layered TX2 structure which has a general formula of (MX)1+x(TX2)n (M=Pb, Bi, Sn, Sb or a rare earth element; T=Ti, V, Cr, Nb or Ta; X=S or Se and n=1, 2, 3). We demonstrate that one of the intercalation compounds (SnS)1.2(TiS2)2 has better thermoelectric properties compared with pure TiS2 in the direction parallel to the layers, as the electron mobility is maintained while the phonon transport is significantly suppressed owing to the reduction in the transverse phonon velocities.

Wan, Chunlei; Wang, Yifeng; Wang, Ning; Norimatsu, Wataru; Kusunoki, Michiko; Koumoto, Kunihito

2010-08-01

227

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

228

Hertizian Generator Development.  

National Technical Information Service (NTIS)

The report summarizes the results of a one-year theoretical and experimental study of the frozen wave Hertzian concept for electromagnetic wave generation. The bulk of the effort was devoted to the switch problem, in particular, switch synchronization. Se...

D. Bailey S. D. Houston

1973-01-01

229

Radioisotope Thermoelectric Generator Transporation System licensed hardware second certification test series and package shock mount system test  

SciTech Connect

This paper presents a summary of two separate drop test a e performed in support of the Radioisotope Thermoelectric Generator (RTG) Transportation System (RTGTS). The first portion of this paper presents the second series of drop testing required to demonstrate that the RTG package design meets the requirements of Title 10, Code of Federal Regulations, ``Part 71`` (10 CFR 71). Results of the first test series, performed in July 1994, demonstrated that some design changes were necessary. The package design was modified to improve test performance and the design changes were incorporated into the Safety Analysis Report for Packaging (SARP). The second full-size certification test article (CTA-2) incorporated the modified design and was tested at the US Department of Energy`s (DOE) Hanford Site near Richland, Washington. With the successful completion of the test series, and pending DOE Office of Facility Safety Analysis approval of the SARP, a certificate of compliance will be issued for the RTG package allowing its use. The second portion of this paper presents the design and testing of the RTG Package Mount System. The RTG package mount was designed to protect the RTG from excessive vibration during transport, provide shock protection during on/off loading, and provide a mechanism for moving the RTG package with a forklift. Military Standard (MIL-STD) 810E, Transit Drop Procedure (DOE 1989), was used to verify that the shock limiting system limited accelerations in excess of 15 G`s at frequencies below 150 Hz. Results of the package mount drop tests indicate that an impact force of 15 G`s was not exceeded in any test from a free drop height of 457 mm (18 in.).

Ferrell, P.C.; Moody, D.A.

1995-10-01

230

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

231

Application of quantum well-like thermocouple to thermoelectric energy harvester by BiCMOS process  

Microsoft Academic Search

This work aims at improving the energy harvester performance by using low-dimensional thermoelectric materials. A micro-thermoelectric generator (?TEG) with quantum well-like thermocouples is developed by state-of-the-art CMOS (Complementary metal-oxide semiconductor) process. A relaxation-time model is applied to analyze the characteristic length of silicon germanium quantum well, and a thermal model is also applied to calculate the thermocouple size for optimal

S. M. Yang; M. Cong; T. Lee

2011-01-01

232

New micro thermoelectric devices based on bismuth telluride-type thin solid films  

Microsoft Academic Search

The sputtering technology for deposition of thermoelectric effective bismuth telluride-type material thin films on foils including pattern generation by photolithography was developed by D.T.S. The properties as electrical conductivity, thermoelectric power and the power factor of such p- and n-type films are presented and the advantages of the thin film technology are explained in relation to the bulk material manufacturing.

Ingo Stark; Matthias Stordeur

1999-01-01

233

THERMOELECTRICAL ENERGY RECOVERY FROM THE EXHAUST OF A LIGHT TRUCK  

Microsoft Academic Search

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. Clarkson University is responsible for project management, vehicle interface design, system modeling, and commercialization plan. Hi-Z Technology, Inc. (sub-contractor to Clarkson)

M Karri; E Thacher; B Helenbrook; M Compeau; A Kushch; N Elsner; M Bhatti; J O Brien; F Stabler

2003-01-01

234

Thermoelectric energy scavenging from waste heat of power amplifier transistors  

Microsoft Academic Search

A thermoelectric (TE) energy scavenging technique is proposed to recover energy from the waste heat of power amplifier (PA) transistors. Explored are optimized pellet geometries for maximum efficiency and performance of TE power generation scavenging energy under various parametric conditions. A fully-coupled TE model is developed and integrates TE physics with heat transfer physics. The TE model is exercised to

Kyoung Joon Kim; Marc Hodes

2009-01-01

235

Vibration Testing of the Pluto/New Horizons Radioisotope Thermoelectric Generator  

SciTech Connect

The Radioisotopic Thermal Generator (RTG) for the Pluto/New Horizons spacecraft was subjected to a flight dynamic acceptance test to demonstrate that it would perform successfully following launch. Seven RTGs of this type had been assembled and tested at Mound, Ohio from 1984 to 1997. This paper chronicles major events in establishing a new vibration test laboratory at the Idaho National Laboratory and the nineteen days of dynamic testing.

Charles D. Griffin

2006-06-01

236

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

Microsoft Academic Search

Bismuth tellurium selenide (Bi2TeySe3?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(NO3)3) in water and to favor the reaction with reduced sources of tellurium and selenium. The resulting powder is

Cham Kim; Dong Hwan Kim; Yoon Soo Han; Jong Shik Chung; SangHa Park; Hoyoung Kim

2011-01-01

237

Nanostructured thermoelectrics: the new paradigm?  

SciTech Connect

This review discusses recent developments and current research in bulk thermoelectric materials in which nanostructuring is a key aspect affecting thermoelectric performance. Systems based on PbTe, AgPb{sub m}SbTe{sub 2+m}, NaPb{sub m}SbTe{sub 2+m}, Bi{sub 2}Te{sub 3}, and Si are given particular emphasis. To date the dramatic enhancements in figure of merit in bulk nanostructured materials come from very large reductions in lattice thermal conductivity rather than improvement in power factors. A discussion of future possible strategies is aimed at enhancing the thermoelectric figure of merit of these materials.

Kanatzidis, M. G. (Materials Science Division); (Northwestern Univ.)

2010-01-01

238

Conversion system overview assessment. Volume 1: solar thermoelectrics  

SciTech Connect

An assessment of thermoelectrics for solar energy conversion is given. There is significant potential for solar thermoelectrics in solar technologies where collector costs are low; e.g., Ocean Thermal Energy Conversion (OTEC) and solar ponds. Reports of two studies by manufacturers assessing the cost of thermoelectric generators in large scale production are included in the appendix and several new concepts thermoelectric systems are presented. (WHK)

Jayadev, T. S.; Henderson, J.; Finegold, J.; Benson, D.

1979-08-01

239

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

Microsoft Academic Search

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

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

1999-01-01

240

Analysis of the inadvertent reentry of the Cassini Spacecraft{close_quote}s Radioisotope Thermoelectric Generators  

SciTech Connect

A rigorous multi-discipline approach has been developed to compute the aero/thermal/structural response of the Cassini Spacecraft{close_quote}s G{underscore}eneral P{underscore}urpose H{underscore}eat S{underscore}ource (GPHS) modules in the unlikely event of accidental reentry of the spacecraft during its Earth gravity-assist maneuver. A new r{underscore}eacting, a{underscore}blating, c{underscore}hemical e{underscore}quilibrium/nonequilibrium with r{underscore}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{underscore}adioisotope T{underscore}hermoelectric G{underscore}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. {copyright} {ital 1999 American Institute of Physics.}

Tobery, E.W. [Lockheed Martin Astronautics, King of Prussia, Pennsylvania 19406 (United States); Bhutta, B.A. [AeroTechnologies, Inc, Yorktown, Virginia 23692 (United States)] [Analysis of the inadvertent reentry of the Cassini Spacecrafts Radioisotope Thermoelectric Generators

1999-01-01

241

Nanostructured Oxides and Sulfides for Thermoelectrics  

NASA Astrophysics Data System (ADS)

Thermoelectric power generation can be applied to various heat sources, both waste heat and renewable energy, to harvest electricity. Even though each heat source is of a small scale, it would lead to a great deal of energy saving if they are combined and collected, and it would greatly contribute to reducing carbon dioxide emission. We have been engaged in developing novel thermoelectric materials to be used for energy saving and environmental protection and are currently developing nanostructured ceramics for thermoelectric conversion. We have demonstrated a quantum confinement effect giving rise to two dimensional electron gas (2DEG) in a 2D superlattice, STO/STO:Nb (STO: strontium titanate), which could generate giant thermopower while keeping high electrical conductivity. One unit-cell thick Nb-doped well layer was estimated to show ZT=2.4 at 300K. Then, a "synergistic nanostructuring" concept incorporating 2DEG grain boundaries as well as nanosizing of grains has been applied to our STO material and 3D superlattice ceramics was designed and proposed. It was verified by numerical simulation that this 3D superlattice ceramics should be capable of showing ZT=1.0 at 300K which is comparable to or even higher than that of conventional bismuth telluride-based thermoelectrics. We have recently proposed titanium disulfide-based misfit-layered compounds as novel TE materials. Insertion of misfit-layers into the van der Waals gaps in layer-structured titanium disulfide thus forming a natural superlattice gives rise to internal nanointerfaces and dramatically reduces its lattice thermal conductivity. ZT value reaches 0.37 at 673 K even without optimization of electronic properties. Our challenge to further increase ZT by controlling their electronic system and superlattice structures will be presented.

Koumoto, Kunihito

2011-03-01

242

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

243

Lunar Base Thermoelectric Power Station Study  

NASA Astrophysics Data System (ADS)

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

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

2006-01-01

244

THERMO-ELECTRIC GENERATOR  

DOEpatents

The conversion of heat energy into electrical energy by a small compact device is descrtbed. Where the heat energy is supplied by a radioactive material and thermopIIes convert the heat to electrical energy. The particular battery construction includes two insulating discs with conductive rods disposed between them to form a circular cage. In the center of the cage is disposed a cup in which the sealed radioactive source is located. Each thermopile is formed by connecting wires from two adjacent rods to a potnt on an annular ring fastened to the outside of the cup, the ring having insulation on its surface to prevent electrica1 contact with the thermopiles. One advantage of this battery construction is that the radioactive source may be inserted after the device is fabricated, reducing the radiation hazard to personnel assembling the battery.

Jordan, K.C.

1958-07-22

245

Modeling thermoelectric transport in organic materials.  

PubMed

Thermoelectric energy converters can directly convert heat to electricity using semiconducting materials via the Seebeck effect and electricity to heat via the Peltier effect. Their efficiency depends on the dimensionless thermoelectric figure of merit of the material, which is defined as zT = S(2)?T/? with S, ?, ?, and T being the Seebeck coefficient, electrical conductivity, thermal conductivity, and absolute temperature respectively. Organic materials for thermoelectric applications have attracted great attention. In this review, we present our recent progress made in developing theories and computational schemes to predict the thermoelectric figure of merit at the first-principles level. The methods have been applied to model thermoelectric transport in closely-packed molecular crystals and one-dimensional conducting polymer chains. The physical insight gained in these studies will help in the design of efficient organic thermoelectric materials. PMID:23086525

Wang, Dong; Shi, Wen; Chen, Jianming; Xi, Jinyang; Shuai, Zhigang

2012-10-19

246

Multistage thermoelectric micro coolers  

Microsoft Academic Search

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

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

2002-01-01

247

Molten gallium flux synthesis of known thermoelectric and novel magnetic inorganic clathrate compounds: Improving thermoelectric performance  

NASA Astrophysics Data System (ADS)

Molten gallium metal has been used as a solvent to grow large single crystals of known inorganic thermoelectric clathrates Sr8Ga 16Ge30, Ba8Ga16Ge30, and Ba8Ga16Si30. X-ray diffraction, thermal analysis, electron microprobe, Glow Discharge Mass Spectrometry, temperature dependent electrical conductivity and Seebeck coefficient measurements characterized the single crystals. The Thermoelectric performance was shown to be heavily dependent on the synthetic conditions including container choice, thermal history and impurity concentration. Inorganic Clathrates have attracted intense interest in last several years as potential new materials for thermoelectric devices. If a small to moderate increase in thermoelectric performance over the currently used materials is realized, substantial environmental and technological gains could be achieved. Since thermoelectric refrigeration modules require no moving parts or heat exchange gas (freon) they offer significant advantages over conventional refrigeration technology that tends to fail due to the finite lifetime of the pumping equipment. High temperature devices are also extremely useful for power generation in harsh unforgiving environments where excess heat is available. The thermoelectric performance, primarily at room temperature, of these compounds was found to be heavily dependent on the synthetic procedures used to obtain them. A flux growth procedure was developed to overcome the problems of the traditional melt-quench-anneal solid-state chemical approach. This procedure yielded large single crystals of the Sr8Ga16Ge 30, Ba8Ga16Ge30 and Ba8Ga 16Si30 compounds which ready facilitated their chemical and electronic study. Finally, an outlook on the application of these compounds as thermoelectric devices is given. Application of the flux method to other systems was also successful in the discovery of two new inorganic clathrate compounds: type IV Eu4Ga 8Ge16 and type V Yb8Ga16Ge14. The Eu4Ga8Ge16 compound was found to be antiferromagnetic with a Tc of 8 K. The compound was investigated by orientated single crystal magnetic susceptibility, heat capacity, Mossbauer spectroscopy and polarized magnetic neutron diffraction. The compound exhibited a nearest-neighbor 1-dimensional ferromagnetic interaction in an overall 3-dimensional ordered antiferromagnetic state. Spin-flop experiments were used to extract the antiferromagnetic exchange coupling constant. The adherence to the Zintl concept was investigated by Mossbauer spectroscopy.

Bryan, John Daniel

248

Thermoelectric property studies on lead chalcogenides, double-filled cobalt tri-antimonide and rare earth-ruthenium-germanium  

Microsoft Academic Search

Motivated by the energy applications of thermoelectrics (TE) such as power generation and refrigeration, my research goal is to develop novel materials with high dimensionless figure-of-merit ZT. Thermoelectric materials are characterized over a broad temperature range from 2 K to 800 K. According to the definition of ZT (=S2sigmaT\\/kappa where S is the Seebeck coefficient, sigma the electrical conductivity, kappa

Huijun Kong

2008-01-01

249

Modeling of on-membrane thermoelectric power supplies  

Microsoft Academic Search

The geometry of on-membrane thermoelectric power supplies has been optimized to obtain the highest useful electric power for a given heating power. Assuming the use of materials with moderate thermoelectric performances, an analytical one-dimensional model has been developed to find the optimum thermoelectric film thickness and leg length together with the best heat source configuration. The optimal geometry of these

A. Jacquot; G. Chen; H. Scherrer; A. Dauscher; B. Lenoir

2004-01-01

250

Oxide Thermoelectrics  

SciTech Connect

Thermoelectricity in oxides, especially NaxCoO2 and related materials, is discussed from the point of view of first principles calculations and Boltzmann transport theory. The electronic structure of this material is exceptional in that it has a combination of very narrow bands and strong hybridization between metal d states and ligand p states. As shown within the framework of conventional Boltzmann transport theory, this leads to high Seebeck coefficients even at metallic carrier densities. This suggests a strategy of searching for other narrow band oxides that can be doped metallic with mobile carriers. Some possible avenues for finding such materials are suggested.

Singh, David J [ORNL

2008-01-01

251

Thermoelectric properties of Ca(1-x-y)Dy(x)CeyMnO3 for power generation.  

PubMed

The sintered Ca(1-x-y)Dy(x)CeyMnO3 bodies were a single phase with a perovskite structure without any impurity phases. The calculated crystallite sizes of the Ca(1-x-y)Dy(x)CeyMnO3 were in the range of 43.3 to 63.3 nm. The composition significantly affected their microstructural and thermoelectric characteristics. The doped Dy led to both an increase in the electrical conductivity as well as the absolute value of the Seebeck coefficient, resulting in an enhanced power factor. The highest power factor (5.1 x 10(-4) Wm(-1) K(-2)) was obtained for Ca(0.8)Dy(0.2)MnO3 at 800 degrees C. In this study, we systematically discussed the thermoelectric properties of the Ca(1-x-y)Dy(x)CeyMnO3, with respect to the substitution of Dy and/or Ce for Ca. PMID:22103151

Park, K; Lee, G W; Jung, J; Kim, S-J; Lim, Y-S; Choi, S-M; Seo, W-S

2011-08-01

252

Thermoelectric Magnetohydrodynamic Stirring of Liquid Metals  

NASA Astrophysics Data System (ADS)

The direct observation of a thermoelectric magnetohydrodynamic (TEMHD) flow has been achieved and is reported here. The origin of the flow is identified based on a series of qualitative tests and corresponds, quantitatively, with a swirling flow TEMHD model. A theory for determining the dominant driver of a free-surface flow, TEMHD or thermocapillary (TC), is found to be consistent with the experimental results. The use of the analytical form for an open geometry develops a new dimensionless parameter describing the ratio of TEMHD to TC generated flows.

Jaworski, M. A.; Gray, T. K.; Antonelli, M.; Kim, J. J.; Lau, C. Y.; Lee, M. B.; Neumann, M. J.; Xu, W.; Ruzic, D. N.

2010-03-01

253

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

SciTech Connect

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

None

2010-03-01

254

Materials for High-Temperature Thermoelectric Conversion.  

National Technical Information Service (NTIS)

The development of materials for high temperature thermoelectric energy conversion devices was investigated. The development of new criteria for the selection of materials which is based on understanding of the fundamental principles governing the behavio...

R. S. Feigelson D. Elwell B. Auld

1984-01-01

255

Development of Advanced Stirling Radioisotope Generator for Space Exploration  

NASA Astrophysics Data System (ADS)

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

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

2007-01-01

256

Preparation of Ring-Shaped Thermoelectric Legs from PbTe Powders for Tubular Thermoelectric Modules  

NASA Astrophysics Data System (ADS)

Waste heat recovery—for example, in automotive applications—is a major field for thermoelectric research and future application. Commercially available thermoelectric modules are based on planar structures, whereas tubular modules may have advantages for integration and performance in the field of automotive waste heat recovery. One major drawback of tubular generator designs is the necessity for ring-shaped legs made from thermoelectric material. Cutting these geometries from sintered tablets leads to considerable loss of thermoelectric material and therefore high cost. Direct sintering of ring-shaped legs or tubes of thermoelectric material is a solution to this problem. However, sintering such rings with high homogeneity and density faces some difficulties related to the mechanical properties of typical thermoelectric materials such as lead telluride (PbTe)—particularly brittleness and high coefficient of thermal expansion. This work shows a process for production of thermoelectric rings made of p- and n-doped PbTe. Long tubes of PbTe have been sintered in a current-assisted sintering process with specially designed sintering molds, coated with a diffusion barrier, and finally cut into ring-shaped slices. To demonstrate the technology, a tubular thermoelectric module has been assembled using these PbTe rings.

Schmitz, Andreas; Stiewe, Christian; Müller, Eckhard

2013-07-01

257

French Steam Generator Design Developments.  

National Technical Information Service (NTIS)

From the outset of the French nuclear power program, a significant R and D effort has been invested in improvement of the design and operation of Pressurized Water Reactors including a special committment to improving steam generators. The steam generator...

R. Ginier J. L. Campan M. Pontier A. Leridon A. Remond

1986-01-01

258

Materials for high-temperature thermoelectric conversion  

NASA Astrophysics Data System (ADS)

The development of materials for high temperature thermoelectric energy conversion devices was investigated. The development of new criteria for the selection of materials which is based on understanding of the fundamental principles governing the behavior of high temperature thermoelectric materials is discussed. The synthesis and characterization of promising new materials and the growth of single crystals to eliminate possible problems associated with grain boundaries and other defects in polycrystalline materials are outlined.

Feigelson, R. S.; Elwell, D.; Auld, B. A.

1984-04-01

259

Impact of In Situ Generated Ag2Te Nanoparticles on the Microstructure and Thermoelectric Properties of AgSbTe2 Compounds  

NASA Astrophysics Data System (ADS)

A series of ternary (Ag2Te) x (Sb2Te3)100- x ( x = 44 to 54) bulk materials with in situ generated Ag2Te nanoparticles were prepared from high-purity elements by combining the melt-quench technique with the spark plasma sintering technique. The influence of the Ag2Te nanoparticles on the thermoelectric transport properties, and the mechanism of nanoparticle formation were investigated. With increasing x, the concentration of the Ag2Te nanoparticles increased monotonically, but their diameter remained nearly unchanged. Due to the possible carrier energy filtering effect caused by the Ag2Te nanoparticle inclusions, the Seebeck coefficient of the sample with x = 50 was two times higher than that of the sample prepared by the melting method. Moreover, notable scattering of mid-to-long wavelength phonons arising from the evenly distributed Ag2Te nanoparticles led to a large reduction of the lattice thermal conductivity. All these effects led to the enhancement of the ZT value of the x = 50 sample (AgSbTe2) compared with the single-phase sample ( x = 44).

Du, B.; Xu, J.; Zhang, W.; Tang, X.

2011-05-01

260

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

261

Thermoelectric heat exchange element  

DOEpatents

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

Callas, James J. (Peoria, IL); Taher, Mahmoud A. (Peoria, IL)

2007-08-14

262

Natural mineral tetrahedrite as a direct source of thermoelectric materials.  

PubMed

We show that a simple powder processing procedure using natural mineral tetrahedrite, the most widespread sulfosalt on earth, provides a low cost, high throughput means of producing thermoelectric materials with high conversion efficiency. These earth-abundant thermoelectrics can open the door to many new and inexpensive power generation opportunities. PMID:23503421

Lu, Xu; Morelli, Donald T

2013-03-18

263

The Effects of Thermoelectric Film Thickness on Performance of In-Plane Thermoelectric Modules  

NASA Astrophysics Data System (ADS)

We fabricated in-plane thermoelectric modules (4 mm × 4 mm) on a 4- ?m-thick substrate using a vacuum deposition process through a shadow mask. In this study, a thermoelectric p- n pair was established using multilayered films of p and n thermoelectric thin films and an insulator film with a hole at the center. The output power was 58 nW at 443 K using the multilayered microgenerator. We discuss the effects of device thickness on the efficiency of the microgenerator to increase the output electric power. We evaluated the output power of the in-plane thermoelectric generator with a substrate using a one-dimensional heat conduction model, and it was found to depend on the thickness of the thermoelectric film. If the thermoelectric film is very thin, the power factor is more important than the nondimensional figure of merit, ZT. Metal thin films with high power factor are more efficient than semiconductors with low power factors even though their thermal conductivities are high. When the thermoelectric thin film is thick, ZT should be higher for larger output power of the device.

Yamamoto, Akihiro; Hagino, Harutoshi; Hashimoto, Yoshihiro; Miyazaki, Koji

2012-06-01

264

MeV Si ion beam modification effects on the thermoelectric generator from Er0.1Fe1.9SbGe0.4 thin film  

NASA Astrophysics Data System (ADS)

Effective thermoelectric materials and devices have a low thermal conductivity and a high electrical conductivity. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT. The purpose of this study is to improve the figure of merit of the single layer of Er0.1Fe1.9SbGe0.4 thin film used as thermoelectric generators. We have deposited the monolayer of Er0.1Fe1.9SbGe0.4 thin film on silicon and silica substrates with thickness of 302 nm using ion beam assisted deposition (IBAD). Rutherford backscattering spectrometry (RBS) was used to determine the total film thickness and stoichiometry. The MeV Si ion bombardments were performed on single layer of Er0.1Fe1.9SbGe0.4 thin films at five different fluences between 5 × 1013-5 × 1015 ions/cm2.The defect and disorder in the lattice caused by ion beam modification and the grain boundaries of these nanoscale clusters increase phonon scattering and increase the chance of annihilation of the phonon. The increase of the electron density of states in the miniband of the quantum dot structure formed by bombardment also increases the Seebeck coefficient and the electrical conductivity. We measured the thermoelectric efficiency of the fabricated device by measuring the cross plane thermal conductivity by the 3rd harmonic (3?) method, the cross plane Seebeck coefficient, and the electrical conductivity using the Van Der Pauw method before and after the MeV ion bombardments.

Budak, S.; Guner, S.; Muntele, C.; Ila, D.

2009-05-01

265

Semiclassical model for thermoelectric transport in nanocomposites  

NASA Astrophysics Data System (ADS)

Nanocomposites (NCs) has recently been proposed and experimentally demonstrated to be potentially high-efficiency thermoelectric materials by reducing the thermal conductivity through phonon-interface scattering and possibly by increasing the Seebeck coefficient through energy-selective carrier scattering (low-energy filtering) or quantum-size effect of electrons. In this paper, we develop a Boltzmann transport equation based semiclassical electron transport model to describe the thermoelectric transport processes in semiconductor NCs. This model considers multiband transport of electrons and holes with both the intrinsic carrier scatterings and the carrier-interface scattering. A relaxation-time model is developed for carrier-interface scattering. After fitting the model with bulk thermoelectric alloys that gives reasonable material input parameters for bulk alloys, which are close to handbook values, the model is further validated by comparing the modeled thermoelectric properties with recently reported measurement values of thermoelectric properties in high efficiency NCs. The model is then applied to predict thermoelectric properties of both the particle-host-type and the particle-particle-type semiconductor NCs such as the p -type (BiySb2-yTe3)-(Bi0.5Sb1.5Te3) NCs and the n -type (Mg2SiyGe1-y)-(Mg2Si0.6Ge0.4) NCs. The dependence of thermoelectric transport coefficients on the size of nanoconstituent, doping concentration and temperature are studied. Our study could shed some light to optimally design high-efficiency thermoelectric NCs which could contribute to solar-thermal utilization or waste heat recovery.

Zhou, Jun; Li, Xiaobo; Chen, Gang; Yang, Ronggui

2010-09-01

266

Design and Development of Multi-Purpose CCD Camera System with Thermoelectric Cooling: Hardware  

NASA Astrophysics Data System (ADS)

We designed and developed a multi-purpose CCD camera system for three kinds of CCDs; KAF-0401E(768×512), KAF-1602E(1536×1024), KAF-3200E(2184×1472) made by KODAK Co.. The system supports fast USB port as well as parallel port for data I/O and control signal. The packing is based on two stage circuit boards for size reduction and contains built-in filter wheel. Basic hardware components include clock pattern circuit, A/D conversion circuit, CCD data flow control circuit, and CCD temperature control unit. The CCD temperature can be controlled with accuracy of approximately 0.4° C in the max. range of temperature, ? 33° C. This CCD camera system has with readout noise 6 e^{-}, and system gain 5 e^{-}/ADU. A total of 10 CCD camera systems were produced and our tests show that all of them show passable performance.

Kang, Y.-W.; Byun, Y. I.; Rhee, J. H.; Oh, S. H.; Kim, D. K.

2007-12-01

267

Thermoelectric Phenomena, Materials, and Applications  

NASA Astrophysics Data System (ADS)

Over the past 10-15 years, there have been significant advances in the scientific understanding as well as in the performance of thermoelectric (TE) materials. TE materials can be incorporated into power generation devices that are designed to convert waste heat into useful electrical energy. These TE materials can also be used in solid-state refrigeration devices for cooling applications. The conversion of waste heat into electrical energy will certainly play a role in our current challenge for alternative energy technologies to reduce our dependence on fossil fuels and to reduce greenhouse gas emissions. This article provides an overview of the various TE phenomena and discusses some of the primary TE materials that are currently being investigated. Several of the key parameters and terminology are defined and discussed along with an overview of some of the current and emerging technologies. The phonon glass-electron crystal approach to new TE materials for developing new materials is presented along with the role of solid-state crystal chemistry and the criteria for higher-performance TE materials. This article discusses TE phenomena, the selection criteria for higher-performance materials, and a few key materials.

Tritt, Terry M.

2011-08-01

268

A Design and Development of Multi-Purpose CCD Camera System with Thermoelectric Cooling: Software  

NASA Astrophysics Data System (ADS)

We present a software which we developed for the multi-purpose CCD camera. This software can be used on the all 3 types of CCD - KAF-0401E (768×512), KAF-1602E (15367times;1024), KAF-3200E (2184×1472) made in KODAK Co.. For the efficient CCD camera control, the software is operated with two independent processes of the CCD control program and the temperature/shutter operation program. This software is designed to fully automatic operation as well as manually operation under LINUX system, and is controled by LINUX user signal procedure. We plan to use this software for all sky survey system and also night sky monitoring and sky observation. As our results, the read-out time of each CCD are about 15sec, 64sec, 134sec for KAF-0401E, KAF-1602E, KAF-3200E., because these time are limited by the data transmission speed of parallel port. For larger format CCD, the data transmission is required more high speed. we are considering this control software to one using USB port for high speed data transmission.

Oh, S. H.; Kang, Y. W.; Byun, Y. I.

2007-12-01

269

Dental Alloy Sorting By the Thermoelectric Method  

PubMed Central

Objectives: A nondestructive, rapid, and practical method of dental alloy sorting is desirable. In this study, the hypothesis to be tested is that dental alloys show significantly different and high thermoelectric power values, on the basis of which alloy sorting is possible. Methods: Six silver-colored commercial dental casting alloys are used in this study: two silver alloys, one gold-silver-palladium alloy, one cobalt-chromium alloy, one nickel-chromium alloy, and one titanium alloy. The thermoelectric power of their castings was determined against constantan using a simple apparatus developed in a previous study. Linear least square fitting was applied to the measured thermal-EMF-temperature curve to determine the thermoelectric power for the temperature ranges of 298–303 K (temperature difference ?t = 5 K), 298–308 K (?t=10 K), 298–313 K (?t=15 K), and 298–318 K (?t=20 K). The results were analyzed using one-way ANOVA and by the Scheffé’s test at a significance level of ?=0.01. Results: When the temperature difference was 10 K or less, the difference in the thermoelectric powers of the alloys was not always statistically significant. However, when the temperature difference was 15 K or more, the thermoelectric powers of the six alloys differed significantly. Conclusions: The results indicated the feasibility of rapid sorting of specific dental alloys by the thermoelectric method, provided a sufficiently large temperature difference is achieved.

Kikuchi, Masafumi

2010-01-01

270

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

271

Phenomenological equation transport model of the stability of p-type (Cu,Ag)âSe as a thermoelectric material  

Microsoft Academic Search

To aid in understanding the behavior of (Cu,Ag)âSe thermoelectric generators, a set of phenomenological equations, which account for thermal fluxes, currents, and copper fluxes (particularly as a neutral species), was developed. A thermodynamic data base for describing copper chemical potentials across the phase existence range of Cu\\/sub (2-x)\\/Se is presented. 6 refs.

J. H. Norman; J. Chin; N. B. Elsner

1981-01-01

272

Generation of an amorphous phase on surface of LiF by thermoelectric effect and its crystallization  

NASA Astrophysics Data System (ADS)

Influence of an electric field and simultaneous heating on a condition of {0 overbar 35}, {110} and {111} crystal surfaces of LiF was investigated. It was shown that the effect resulted in structural changes shown as a jelly uncertain form formations. Generation of the amorphous phase was caused by the change of stoichiometry and accumulation of a charge in superficial layers. Fast growth of crystals is a result of photoeffect. Crystallization of neoplasm at seasoning in full darkness is caused by a relaxation of a volumetric charge and restoration of stoichiometric structure.

Feodorov, Victor A.; Sterelukhin, Andrei A.; Karyev, Leonid G.

2005-04-01

273

Open porous foam oxide thermoelectric elements for hot gases and liquid environments  

Microsoft Academic Search

The development of open porous foams from a variety of substances such as polymers, metals and ceramics has led to many interesting applications of the porous structures. The large open porosity and high surface area of foams from oxide thermoelectric materials could also bring about new thermoelectric module designs. Currently, thermoelectric modules with bulk elements are mostly designed to extract

E. Sudhakar Reddy; J. G. Noudem; C. Goupil

2007-01-01

274

THERMOELECTRIC NUCLEAR FUEL ELEMENT. Third Quarterly Progress Report January 10, 1960  

Microsoft Academic Search

Thermoelectric materials were prepared for irradiation and fabrication ; studies, and techniques were developed for the preparation of some uranium-; bearing thermoelectric materials. Additional apparatus was set up to handle an ; increase in samples requiring measurements of Seebeck coefficient, resistivity, ; and thermal conductivity of thermoelectric materials being processed in the ; various phases of the project. Results are

G. R. Kilp; A. Biancheria; P. V. Mitchell; S. W. Sandberg

1960-01-01

275

Sustainable Development and Future Generations  

Microsoft Academic Search

This paper argues, mainly on thebasis of Rawls's savings principle,Wissenburg's restraint principle, Passmore'schains of love, and De-Shalit'stransgenerational communities, for a doubleinterpretation of sustainable development as aprinciple of intergenerational justice and afuture-oriented green ideal. This doubleinterpretation (1) embraces the restraintprinciple and the argument that no individualcan claim an unconditional right to destroyenvironmental goods as a baseline that couldjustify directive strategies for

Volkert Beekman

2004-01-01

276

Subsea thermoelectric generators. 1- 10-watt peltier effect prototypes - a step towards autonomous electrical control units at subsea wellheads  

Microsoft Academic Search

Offshore oil production activities require the operation of underwater hydraulic or electric equipment. The high cost of acquisition and installation of umbilical cables to supply power is leading to the development of independently powered cableless equipment, connected to the surface by the transmission and reception of control signals through the water. As a first step toward these autonomous wellhead control

J. P. von der Weid; J. A. P. da Silva; A. L. Gama; A. C. SantAnna

1994-01-01

277

100 Watt Thermoelectric Power System for Buoy Applications.  

National Technical Information Service (NTIS)

During this reporting period the preliminary design of the thermoelectric generator, electric control, fuel piping and air ducting has been finalized and the information is in drafting. The mechanical design of the control unit was changed to incorporate ...

1964-01-01

278

In-line thermoelectric module  

DOEpatents

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

Pento, Robert (Algonquin, IL); Marks, James E. (Glenville, NY); Staffanson, Clifford D. (S. Glens Falls, NY)

2000-01-01

279

In-line thermoelectric module  

SciTech Connect

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

Pento, R.; Marks, J.E.; Staffanson, C.D.

2000-02-01

280

In-Line Thermoelectric Module  

DOEpatents

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

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

1998-07-28

281

Advanced high temperature thermoelectrics for space power  

SciTech Connect

Nuclear-electric propulsion is under consideration for future outer planet missions. A minimum generator capacity of 100 KWe is required. Preliminary results from a spacecraft system study show that an optimum hot junction temperature is in the range of 1500 K for advanced nuclear reactor technology combined with thermoelectric conversion. 7 refs.

Lockwood, A.; Ewell, R.; Wood, C.

1981-01-01

282

Towards a Microbial Thermoelectric Cell  

PubMed Central

Microbial growth is an exothermic process. Biotechnological industries produce large amounts of heat, usually considered an undesirable by-product. In this work, we report the construction and characterization of the first microbial thermoelectric cell (MTC), in which the metabolic heat produced by a thermally insulated microbial culture is partially converted into electricity through a thermoelectric device optimized for low ?T values. A temperature of 41°C and net electric voltage of around 250–600 mV was achieved with 1.7 L baker’s yeast culture. This is the first time microbial metabolic energy has been converted into electricity with an ad hoc thermoelectric device. These results might contribute towards developing a novel strategy to harvest excess heat in the biotechnology industry, in processes such as ethanol fermentation, auto thermal aerobic digestion (ATAD) or bioremediation, which could be coupled with MTCs in a single unit to produce electricity as a valuable by-product of the primary biotechnological product. Additionally, we propose that small portable MTCs could be conceived and inoculated with suitable thermophilic of hyperthermophilic starter cultures and used for powering small electric devices.

Rodriguez-Barreiro, Raul; Abendroth, Christian; Vilanova, Cristina; Moya, Andres; Porcar, Manuel

2013-01-01

283

Development of the Power Sources for the Ulysses and Galileo Missions.  

National Technical Information Service (NTIS)

The development of the Radioisotope Thermoelectric Generator (RTG) to be used on the Ulysses and Galileo missions is described. This RTG, designed to provide a minimum of 285 We at the beginning of the mission, builds upon the successful thermoelectric te...

G. L. Bennett C. W. Whitmore W. R. Amos

1989-01-01

284

Fourth-generation photovoltaic concentrator system development  

Microsoft Academic Search

In 1991, under a contract with Sandia for the Concentrator Initiative, the ENTECH team initiated the design and development of a fourth-generation concentrator module. In 1992, Sandia also contracted with ENTECH to develop a new control and drive system for the ENTECH array. This report documents the design and development work performed under both contracts. Manufacturing processes for the new

A. J. McDanal

1995-01-01

285

New developments in Generator Services project  

NASA Astrophysics Data System (ADS)

The LOG Generator Services project provides validated, LOG compliant Monte Carlo generators code for both the theoretical and experimental communities at the LHC. In this paper we present the recent developments and the future plans of the project. We report on the current status of the generators repository, the new Autotools-based build system, as well as the new installation tools to create mirrors of the repository. We discuss new developments in testing and physics validation procedures in particular the use of HepMC Analysis Tool, as well as the Rivet validation tool. We also present a new activity, enlarging the scope of the Generator Services project, it is the involvement in the tuning of the Monte Carlo generators. This work, being essential for the understanding of the future LHC data, is now starting with the involvement of all the LHC experiments.

Karneyeu, A.; Kirsanov, M.; Konstantinov, D.; Pokorski, W.; Ribon, A.; Ryabov, A.; Zenin, O.

2011-12-01

286

Atomically thick bismuth selenide freestanding single layers achieving enhanced thermoelectric energy harvesting.  

PubMed

Thermoelectric materials can realize significant energy savings by generating electricity from untapped waste heat. However, the coupling of the thermoelectric parameters unfortunately limits their efficiency and practical applications. Here, a single-layer-based (SLB) composite fabricated from atomically thick single layers was proposed to optimize the thermoelectric parameters fully. Freestanding five-atom-thick Bi(2)Se(3) single layers were first synthesized via a scalable interaction/exfoliation strategy. As revealed by X-ray absorption fine structure spectroscopy and first-principles calculations, surface distortion gives them excellent structural stability and a much increased density of states, resulting in a 2-fold higher electrical conductivity relative to the bulk material. Also, the surface disorder and numerous interfaces in the Bi(2)Se(3) SLB composite allow for effective phonon scattering and decreased thermal conductivity, while the 2D electron gas and energy filtering effect increase the Seebeck coefficient, resulting in an 8-fold higher figure of merit (ZT) relative to the bulk material. This work develops a facile strategy for synthesizing atomically thick single layers and demonstrates their superior ability to optimize the thermoelectric energy harvesting. PMID:23214984

Sun, Yongfu; Cheng, Hao; Gao, Shan; Liu, Qinghua; Sun, Zhihu; Xiao, Chong; Wu, Changzheng; Wei, Shiqiang; Xie, Yi

2012-12-11

287

Direct Evaluation of the Figure of Merit of Thermoelectric Devices by Guarded Hot Plate Method  

NASA Astrophysics Data System (ADS)

An apparatus for the evaluation of the figure of merit (\\mathit{ZT}) of thermoelectric devices has been developed and \\mathit{ZT} values have been estimated for a thermoelectric device. The most challenging problem in \\mathit{ZT} value evaluation in this apparatus was measuring the thermal conductivity of the devices precisely. We have solved the problem by introducing a primary thermal conductivity measurement technique, a guarded hot plate method, which makes it possible to obtain directly and simultaneously four physical parameters related to the \\mathit{ZT}, namely the thermal conductivity, electrical conductivity, Seebeck coefficient, and absolute temperature. The \\mathit{ZT} evaluation was performed by a single scan of the temperature difference between the top and bottom surfaces of the device. We also addressed the thermoelectric properties and the power generation efficiency of a commercial thermoelectric device. The evaluation uncertainty of the \\mathit{ZT} value was assessed to secure reliability of the apparatus and was found to be 3.59%.

Kwon, Su Yong; Kim, Yong-Gyoo; Lee, Sanghyun; Kim, Jong Chul

2013-03-01

288

Revisiting some chalcogenides for thermoelectricity  

NASA Astrophysics Data System (ADS)

Thermoelectric materials that are efficient well above ambient temperature are needed to convert waste-heat into electricity. Many thermoelectric oxides were investigated for this purpose, but their power factor (PF) values were too small (˜10-4 W m-1 K-2) to yield a satisfactory figure of merit zT. Changing the anions from O2- to S2- and then to Se2- is a way to increase the covalency. In this review, some examples of sulfides (binary Cr-S or derived from layered TiS2) and an example of selenides, AgCrSe2, have been selected to illustrate the characteristic features of their physical properties. The comparison of the only two semiconducting binary chromium sulfides and of a layered AgCrSe2 selenide shows that the PF values are also in the same order of magnitude as those of transition metal oxides. In contrast, the PF values of the layered sulfides TiS2 and Cu0.1TiS2 are higher, reaching ˜10-3 W m-1 K-2. Apparently the magnetism related to the Cr-S network is detrimental for the PF when compared to the d0 character of the Ti4+ based sulfides. Finally, the very low PF in AgCrSe2 (PF = 2.25 × 10-4 W m1 K-2 at 700 K) is compensated by a very low thermal conductivity (? = 0.2 W m-1 K-1 from the measured Cp) leading to the highest zT value among the reviewed compounds (zT700K = 0.8). The existence of a glassy-like state for the Ag+ cations above 475 K is believed to be responsible for this result. This result demonstrates that the phonon engineering in open frameworks is a very interesting way to generate efficient thermoelectric materials.

Maignan, Antoine; Guilmeau, Emmanuel; Gascoin, Franck; Bréard, Yohann; Hardy, Vincent

2012-10-01

289

Fourth-generation photovoltaic concentrator system development  

SciTech Connect

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

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

1995-10-01

290

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

PubMed

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

Xie, Ming; Gruen, Dieter M

2010-03-02

291

Development of an Mg2Si Unileg Thermoelectric Module Using Durable Sb-Doped Mg2Si Legs  

NASA Astrophysics Data System (ADS)

Mg2Si unileg structure thermoelectric (TE) modules, which are composed only of n-type Mg2Si legs, were fabricated using Sb-doped Mg2Si. The Mg2Si TE legs used in our module were fabricated by a plasma-activated sintering method using material produced from molten commercial doped polycrystalline Mg2Si, and, at the same time, nickel electrodes were formed on the Mg2Si using a monobloc plasma-activated sintering technique. The source material used for our legs has a ZT value of 0.77 at 862 K. The TE modules, which have dimensions of 21 mm × 30 mm × 16 mm, were composed of ten legs that were connected in series electrically using nickel terminals, and the dimensions of a single leg were 4.0 mm × 4.0 mm × 10 mm. From evaluations of the measured output characteristics of the modules, it appeared that the electrical resistance of the wiring that is used to connect each leg considerably affects the power output of the unileg module. Thus, we attempted to reduce the wiring resistance of the module and fabricated a module using copper terminals. The observed values of the open-circuit voltage and output power of the Sb-doped Mg2Si unileg module were 496 mV and 1211 mW at ?T = 531 K (hot side: 873 K; cool side: 342 K).

Nemoto, Takashi; Iida, Tsutomu; Sato, Junichi; Sakamoto, Tatsuya; Hirayama, Naomi; Nakajima, Tadao; Takanashi, Yoshihumi

2013-04-01

292

Development of an Mg2Si Unileg Thermoelectric Module Using Durable Sb-Doped Mg2Si Legs  

NASA Astrophysics Data System (ADS)

Mg2Si unileg structure thermoelectric (TE) modules, which are composed only of n-type Mg2Si legs, were fabricated using Sb-doped Mg2Si. The Mg2Si TE legs used in our module were fabricated by a plasma-activated sintering method using material produced from molten commercial doped polycrystalline Mg2Si, and, at the same time, nickel electrodes were formed on the Mg2Si using a monobloc plasma-activated sintering technique. The source material used for our legs has a ZT value of 0.77 at 862 K. The TE modules, which have dimensions of 21 mm × 30 mm × 16 mm, were composed of ten legs that were connected in series electrically using nickel terminals, and the dimensions of a single leg were 4.0 mm × 4.0 mm × 10 mm. From evaluations of the measured output characteristics of the modules, it appeared that the electrical resistance of the wiring that is used to connect each leg considerably affects the power output of the unileg module. Thus, we attempted to reduce the wiring resistance of the module and fabricated a module using copper terminals. The observed values of the open-circuit voltage and output power of the Sb-doped Mg2Si unileg module were 496 mV and 1211 mW at ? T = 531 K (hot side: 873 K; cool side: 342 K).

Nemoto, Takashi; Iida, Tsutomu; Sato, Junichi; Sakamoto, Tatsuya; Hirayama, Naomi; Nakajima, Tadao; Takanashi, Yoshihumi

2013-07-01

293

Research and Development Directed Toward the Development of Gas Generators.  

National Technical Information Service (NTIS)

The purpose of this project is to develop improved gas generators to activate zinc-silver oxide batteries employing the Signal Corps metal-tube electrolytereservoir activating system. The results of the propellant investigation indicated that one commerci...

F. Schumacher D. Fyfe

1965-01-01

294

Development of a Downhole Steam Generator System.  

National Technical Information Service (NTIS)

This report describes the development of a downhole steam generator system for use in enhanced oil recovery. The system is composed of four major components: A state-of-the-art review indicated that advances in technology would be necessary in two areas (...

1984-01-01

295

Development of Tungsten-Tantalum Generator.  

National Technical Information Service (NTIS)

The purpose of this project was to develop a useable tungsten (W)/tantalum (Ta) generator. Ta-178 is formed following the decay of its parent, W-178 (half-life: 21.7d) and has a half life of 9.3 minutes in turn yielding stable Hf-178. The decay of the par...

A. Leblanc J. Babich S. G. Jhingran

1985-01-01

296

Refractory Materials for High-Temperature Thermoelectric Energy Conversion.  

National Technical Information Service (NTIS)

Theoretical work of two decades ago adequately explained the transport behavior and effectively guided the development of thermoelectric materials of high conversion efficiencies of conventional semiconductors (e.g., SiGe alloys). The more significant con...

C. Wood D. Emin

1983-01-01

297

Multilayered carbon nanotube/polymer composite based thermoelectric fabrics.  

PubMed

Thermoelectrics are materials capable of the solid-state conversion between thermal and electrical energy. Carbon nanotube/polymer composite thin films are known to exhibit thermoelectric effects, however, have a low figure of merit (ZT) of 0.02. In this work, we demonstrate individual composite films of multiwalled carbon nanotubes (MWNT)/polyvinylidene fluoride (PVDF) that are layered into multiple element modules that resemble a felt fabric. The thermoelectric voltage generated by these fabrics is the sum of contributions from each layer, resulting in increased power output. Since these fabrics have the potential to be cheaper, lighter, and more easily processed than the commonly used thermoelectric bismuth telluride, the overall performance of the fabric shows promise as a realistic alternative in a number of applications such as portable lightweight electronics. PMID:22316286

Hewitt, Corey A; Kaiser, Alan B; Roth, Siegmar; Craps, Matt; Czerw, Richard; Carroll, David L

2012-02-16

298

Nanoscale heat transfer and thermoelectrics for alternative energy  

NASA Astrophysics Data System (ADS)

In the area of alternative energy, thermoelectrics have experienced an unprecedented growth in popularity because of their ability to convert waste heat into electricity. Wired in reverse, thermoelectrics can act as refrigeration devices, where they are promising because they are small in size and lightweight, have no moving parts, and have rapid on/off cycles. However, due to their low efficiencies bulk thermoelectrics have historically been a niche market. Only in the last decade has thermoelectric efficiency exceeded ˜20% due to fabrication of nanostructured materials. Nanoscale materials have this advantage because electronic and acoustic confinement effects can greatly increase thermoelectric efficiency beyond bulk values. In this talk, I will introduce our work in the area of nanoscale heat transfer with the goal of more efficient thermoelectrics. I will discuss our experiments and methods to study acoustic confinement in nanostructures and present some of our new nanostructured thermoelectric materials. To study acoustic confinement we are building a nanoscale phonon spectrometer. The instrument can excite phonon modes in nanostructures in the ˜100s of GHz. Ballistic phonons from the generator are used to probe acoustic confinement and surface scattering effects. Transmission studies using this device will help optimize materials and morphologies for more efficient nanomaterial-based thermoelectrics. For materials, our group has synthesized nano-layer superlattices of NaxCoO2. Sodium cobaltate was recently discovered to have a high Seebeck coeficent and is being studied as an oxide thermoelectric material. The thickness of our nano-layers ranges from 5 nm to 300 nm while the lengths can be varied between 10 ?m and 4 mm. Typical aspect ratios are 40 nm: 4 mm, or 1:100,000. Thermoelectric characterization of samples with tilted multiple-grains along the measurement axis indicate a thermoelectric efficiency on par with current polycrystalline samples. Due to phonon confinement in nano-structures, it is expected that the thermoelectric efficiency of these sheets will be much higher than that of single crystalline Na0.7CoO2, when the nanosheets have single grains along the heat transport path.

Robinson, Richard

2011-03-01

299

Investigations on an oriented cooling design for thermoelectric cogenerations  

NASA Astrophysics Data System (ADS)

In thermoelectric application, it is widely known that the material limitation has still been the chief barrier of lifting its application to a higher level. Continuous efforts are extensively being made in developing novel material structures and constructions for thermoelectric modules with higher conversion efficiency. However, the overall system efficiency, which is one of the major parameters that most of the engineer and users care about, is not only ruled by the properties of applied thermoelectric materials, but also decided by the design of heat exchangers used on both sides of thermoelectric modules. Focusing on the cooling capacity and hydraulic characteristics of heat exchanger, this paper introduces an oriented cooling method for the domestic thermoelectric cogeneration, which delivers system efficiency up to 80%. This purpose-oriented cooling plate is designed for thermoelectric cogeneration for the residential houses installed with boiler or other heating facilities with a considerable amount of unused heat. The design enables Thermoelectric Cogeneration System (TCS) to be flexibly integrated into the existing hydraulic system. The mathematical model for the cooling plate has been established for a well understanding at the theoretical level. The performance of cooling plate has been investigated in a series of experimental studies which have been conducted under different coolant inlet velocity and temperature. The economic operating zone in which a good system performance could be achieved has been discussed and identified for the current configuration.

Zheng, X. F.; Liu, C. X.; Yan, Y. Y.

2012-11-01

300

Energy Harvesting for Electronics with Thermoelectric Devices using Nanoscale Materials  

Microsoft Academic Search

Significant developments have occurred in the last few years in the area of nanoscale thermoelectric materials using superlattices and self-assembled quantum-dots. Thin-film thermoelectric (TE) devices employing these materials have been developed for many applications including energy harvesting. Thin-film TE devices, for a 1 mm3 of converter volume, are available that can produce well over 775 muW\\/mm3 with an external DeltaT

R. Venkatasubramanian; C. Watkins; D. Stokes; J. Posthill; C. Caylor

2007-01-01

301

Thermoelectric Terminology in Metrology and Standards.  

National Technical Information Service (NTIS)

In metrology and standards, thermoelectricity is most often associated with thermometry. Therefore, this paper emphasizes thermoelectricity in thermometry and it focuses on the Seebeck effect. Yet, the thermoelectric terminology applies generally to all t...

R. P. Reed

1989-01-01

302

Enhancement of automotive exhaust heat recovery by thermoelectric devices  

SciTech Connect

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

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

2010-01-01

303

Thermoelectric Phenomena, Materials, Devices, and Applications  

NASA Astrophysics Data System (ADS)

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

Toberer, Eric

2013-03-01

304

Landauer approach to thermoelectrics  

NASA Astrophysics Data System (ADS)

Many efforts have been made to search for materials that maximize the thermoelectric (TE) figure of merit, ZT, but for decades, the improvement has been limited because of the interdependent material parameters that determine ZT. Recently, several breakthroughs have been reported by applying nanotechnology. To further enhance ZT, a clear understanding of electronic and thermal transport is necessary. The objectives of this thesis are: 1) to evaluate the electronic and thermal performance with a Landauer approach using full band electronic bandstructure and a full dispersion description of phonons, 2) to show how the Landauer treatment gives new insights to the understanding of thermoelectrics, and 3) to discuss possibilities for enhancing TE performance. We first present a Landauer approach for computing TE parameters using a full band electronic bandstructure. The full band results are related to the more common effective mass formalism. Next, a full dispersion description of phonons is used to calculate the thermal conductivities of bulk and thin films using a Landauer approach. It is shown that simplified dispersion models for phonons should be used with caution and that the Landauer approach provides a relatively simple (but accurate) technique to treat phonon transport from the ballistic to diffusive regimes. We also address the question of how to engineer the electronic structure to enhance the performance of a thermoelectric material by re-visiting from a Landauer perspective the question of what bandstructure produces the best thermoelectric device performance. Next, we explore the possibilities of increasing ZT through multi-barrier structures, quantum engineered graphene and molecules, high valley degeneracy, or by distorting the density-of-states. Finally, we shift our attention to nanocomposite thermoelectric materials and discuss a new approach to model nanocomposite TE devices. Using polycrystalline graphene as a testbed of our model, we study how grain boundaries affect the electronic performance of large-area polycrystalline graphene and propose the new approach of `percolation-doping by nanowires' to beat the transparency-conductivity constraints.

Jeong, Changwook

305

Thermoelectric powered wireless sensors for spent fuel monitoring  

SciTech Connect

This paper describes using thermoelectric generators to power wireless sensors to monitor spent nuclear fuel during dry-cask storage. OrigenArp was used to determine the decay heat of the spent fuel at different times during the service life of the dry-cask. The Engineering Equation Solver computer program modeled the temperatures inside the spent fuel storage facility during its service life. The temperature distribution in a thermoelectric generator and heat sink was calculated using the computer program Finite Element Heat Transfer. From these temperature distributions the power produced by the thermoelectric generator was determined as a function of the service life of the dry-cask. In addition, an estimation of the path loss experienced by the wireless signal can be made based on materials and thickness of the structure. Once the path loss is known, the transmission power and thermoelectric generator power requirements can be determined. This analysis estimates that a thermoelectric generator can produce enough power for a sensor to function and transmit data from inside the dry-cask throughout its service life. (authors)

Carstens, T.; Corradini, M.; Blanchard, J. [Dept. of Engineering Physics, Univ. of Wisconsin-Madison, Madison, WI 53706 (United States); Ma, Z. [Dept. of Electrical and Computer Engineering, Univ. of Wisconsin-Madison, Madison, WI 53706 (United States)

2011-07-01

306

Thermal Shunts in Thermoelectric Energy Scavengers  

Microsoft Academic Search

The necessity for an additional component in thermoelectric generators and low-dimensional thermopiles for improving the efficiency\\u000a of energy scavengers is discussed. Energy scavengers usually work at a small temperature difference and high thermal resistance\\u000a of the heat source and sink, i.e., of the environment. The name “thermal shunt” is given to this component because, firstly,\\u000a it is connected thermally in

V. Leonov

2009-01-01

307

Thermoelectric automotive waste heat energy recovery using maximum power point tracking  

Microsoft Academic Search

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

Chuang Yu; K. T. Chau

2009-01-01

308

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

PubMed

A hand-held fully electrically powered and programmable cryoprobe for general-purpose cryosurgery and cryotherapy has been developed. By combining the technologies of thermoelectric cooling and heat pipes, the temperature at the tip of the probe can easily reach -50 to -60 degrees C. It can hold below -40 degrees C when it cools a load of 10 W at the tip. Previous efforts developing cryoprobes made of thermoelectric modules have been hindered by the inherent characteristics of commercially available thermoelectric coolers: low efficiency, size and inflexible shape and very sensitive to heat intensity and thermal insulation. Matching thermoelectrics with heat pipes uses the advantages of both technologies. In the cryoprobe the heat pipe is used to focus and transport the cooling power of multi-thermoelectric modules. The heat flux for the thermoelectric modules is reduced and their efficiencies are increased. The transport of heat by a heat pipe also allows flexible access to treated spots of patients. PMID:8263903

Hamilton, A; Hu, J

309

Thermoelectric device for treatment of radiculitis and spinal massage  

NASA Astrophysics Data System (ADS)

Results of development of a thermoelectric device that enables controlled cyclic temperature impact on the damaged area of human organism are presented. Unlike the existing medical devices employing direct supply current for thermoelectric module, the present device controls supply current according to time dependence of temperature change assigned by doctor. It is established that such a device is an efficient means of therapy at herniation of intervertebral disks with marked radiculitis and tunicary syndromes, at meningitis, other spinal diseases and back traumas.

Anatychuk, L. I.; Kobylyansky, R. R.

2012-06-01

310

Prenatal development of central rhythm generation.  

PubMed

Foetal breathing in mice results from prenatal activity of the two coupled hindbrain oscillators considered to be responsible for respiratory rhythm generation after birth: the pre-Bötzinger complex (preBötC) is active shortly before the onset of foetal breathing; the parafacial respiratory group (e-pF in embryo) starts activity one day earlier. Transcription factors have been identified that are essential to specify neural progenitors and lineages forming each of these oscillators during early development of the neural tube: Hoxa1, Egr2 (Krox20), Phox2b, Lbx1 and Atoh1 for the e-pF; Dbx1 and Evx1 for the preBötC which eventually grow contralateral axons requiring expression of Robo3. Inactivation of the genes encoding these factors leads to mis-specification of these neurons and distinct breathing abnormalities: apneic patterns and loss of central chemosensitivity for the e-pF (central congenital hypoventilation syndrome, CCHS, in humans), complete loss of breathing for the preBötC, right-left desynchronized breathing in Robo3 mutants. Mutations affecting development in more rostral (pontine) respiratory territories change the shape of the inspiratory drive without affecting the rhythm. Other (primordial) embryonic oscillators start in the mouse three days before the e-pF, to generate low frequency (LF) rhythms that are probably required for activity-dependent development of neurones at embryonic stages; in the foetus, however, they are actively silenced to avoid detrimental interaction with the on-going respiratory rhythm. Altogether, these observations provide a strong support to the previously proposed hypothesis that the functional organization of the respiratory generator is specified at early stages of development and is dual in nature, comprising two serially non-homologous oscillators. PMID:21527363

Champagnat, Jean; Morin-Surun, Marie-Pierre; Bouvier, Julien; Thoby-Brisson, Muriel; Fortin, Gilles

2011-04-16

311

Future development of large superconducting generators  

SciTech Connect

Large superconducting generators are being developed worldwide. The use of superconductors to reduce the electrical power dissipation in power equipment has been a technological possibility ever since the discovery of superconductivity, even though their use in power equipment remained an impractical dream for a long time. However, scientific and technological progress in superconductivity and cryogenics has brought this dream much closer to reality. Results obtained so far establish the technical feasibility of these machines. Analytical developments have been providing a sound basis for the design of superconducting machines and results of these design studies have shown improvements in power density of up to a factor of 10 higher than the power density for conventional machines. This paper describes the recently completed USA programs, the current foreign and USA programs, and then proposes a USA development program to maintain leadership in the field.

Singh, S.K.; Mole, C.J.

1989-03-01

312

Theoretical investigations of the thermoelectrically induced magnetic field in thermoelectric metal materials characterization  

NASA Astrophysics Data System (ADS)

The objective of this study is to demonstrate that the thermoelectric coupling inherent in metal materials can be exploited as a viable mean in characterizing material imperfections in a noncontacting way. These include, but not limited to, inclusions, inhomogeneity, and anisotropy. Essentially all existing thermoelectric techniques are based on the well-know Seebeck effect that is used in thermocouples to measure temperature at the junction of two different conductors. These conventional techniques are solely sensitive to intrinsic material variations regardless of the shape and surface quality of the specimen to be inspected. However, they require a very good metallic contact between the specimen and the reference electrode; therefore the detectability of small material variations and imperfections is limited by the presence of the imperfect contact. On the other hand, the new noncontacting thermoelectric method uses the surrounding intact material as the reference electrode; thus provides perfect interface between the region to be tested and the surrounding material. The first part of this work deals with infinitely extended media and develops theoretical models to predict the thermoelectric magnetic field around the material imperfections. The already available results for conical inclusion geometries are extended to present more complicated-geometry inclusions. The effects of the shape and orientation of the inclusion on the signal magnitude were investigated. Furthermore, the presence of the material anisotropy is introduced and modeled. Results are obtained for the case of holes and inclusions in infinitely extended media. Like most other methods used in nondestructive evaluation, the detection sensitivity of the noncontacting thermoelectric method is limited by unwanted background signal that interferes with, and often, conceals the flaw signal to be detected. The second part of this work is devoted to model such background signal in finite-size specimens. Two sources of the thermoelectric background signal are considered, namely, material inhomogeneity and anisotropy. The predictions of the analytical models resemble the experimental results recorded in the literature.

Faidi, Waseem Ibrahim

313

The thermodynamics of reversible thermoelectric nanomaterials  

NASA Astrophysics Data System (ADS)

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 via the same physical mechanism utilized in the three-level amplifier (thermally pumped laser) and idealized thermophotovoltaic and thermionic devices. From a broader physical perspective, the most interesting aspect of this work is that it suggests that all of the above-mentioned solid-state devices may be unified as a single `type' of heat engine which achieves reversibility when heat transfer via particle exchange between reservoirs is isentropic (but non-isothermal), in contrast to heat engines such as Carnot, Otto or Brayton cycles, which achieve reversibility when heat transfer between the working gas and heat reservoirs is isothermal.

Humphrey, Tammy; Linke, Heiner

2005-03-01

314

Development of a downhole steam generator system  

SciTech Connect

This report describes the development of a downhole steam generator system for use in enhanced oil recovery. The system is composed of four major components: A state-of-the-art review indicated that advances in technology would be necessary in two areas (high pressure combustion and high temperature packer seals) in order to fabricate a field-worthy system. As a result, two tasks were undertaken which resulted in the development of a novel ceramic-lined combustor and a unique all-metal packer. These elements were incorporated into an overall system design. Key system components were built and tested in the laboratory. The program culminated in a successful simulated downhole test of the entire system, less tube string, at Sandia National Laboratories. 5 references, 41 figures, 9 tables.

Not Available

1984-04-01

315

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

NASA Astrophysics Data System (ADS)

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

Miara, Ariel; Vörösmarty, Charles J.; Stewart, Robert J.; Wollheim, Wilfred M.; Rosenzweig, Bernice

2013-06-01

316

An inconvenient truth about thermoelectrics.  

PubMed

Despite recent advances, thermoelectric energy conversion will never be as efficient as steam engines. That means thermoelectrics will remain limited to applications served poorly or not at all by existing technology. Bad news for thermoelectricians, but the climate crisis requires that we face bad news head on. PMID:19165205

Vining, Cronin B

2009-02-01

317

Thermoelectric strategy for consumer applications  

Microsoft Academic Search

It is possible to increase the thermoelectric market in the consumer segment as much as 50 to 100 times the existing size even with today's level of technology. There are three important things for it, which are very inexpensive to do. First of all, thermoelectric experts should enlighten people in an application oriented manner. Most experts always talk about only

H. Watanabe

1998-01-01

318

Method for thin film thermoelectric module fabrication  

US Patent & Trademark Office Database

Methods of fabrication of a thermoelectric module from thin film thermoelectric material are disclosed. In general, a thin film thermoelectric module is fabricated by first forming an N-type thin film thermoelectric material layer and one or more metallization layers on a substrate. The one or more metallization layers and the N-type thin film thermoelectric material layer are etched to form a number of N-type thermoelectric material legs. A first electrode assembly is then bonded to a first portion of the N-type thermoelectric material legs, and the first electrode assembly including the first portion of the N-type thermoelectric material legs is removed from the substrate. In a similar manner, a second electrode assembly is bonded to a first portion of a number of P-type thermoelectric material legs. The first and second electrode assemblies are then bonded using a flip-chip bonding process to complete the fabrication of the thermoelectric module.

2012-07-10

319

Scalable Silicon Nanostructuring for Thermoelectric Applications  

NASA Astrophysics Data System (ADS)

The current limitations of commercially available thermoelectric (TE) generators include their incompatibility with human body applications due to the toxicity of commonly used alloys and possible future shortage of raw materials (Bi-Sb-Te and Se). In this respect, exploiting silicon as an environmentally friendly candidate for thermoelectric applications is a promising alternative since it is an abundant, ecofriendly semiconductor for which there already exists an infrastructure for low-cost and high-yield processing. Contrary to the existing approaches, where n/ p-legs were either heavily doped to an optimal carrier concentration of 1019 cm-3 or morphologically modified by increasing their roughness, in this work improved thermoelectric performance was achieved in smooth silicon nanostructures with low doping concentration (1.5 × 1015 cm-3). Scalable, highly reproducible e-beam lithographies, which are compatible with nanoimprint and followed by deep reactive-ion etching (DRIE), were employed to produce arrays of regularly spaced nanopillars of 400 nm height with diameters varying from 140 nm to 300 nm. A potential Seebeck microprobe (PSM) was used to measure the Seebeck coefficients of such nanostructures. This resulted in values ranging from -75 ?V/K to -120 ?V/K for n-type and 100 ?V/K to 140 ?V/K for p-type, which are significant improvements over previously reported data.

Koukharenko, E.; Boden, S. A.; Platzek, D.; Bagnall, D. M.; White, N. M.

2013-07-01

320

Hybrid thermoelectric solar collector design and analysis  

NASA Astrophysics Data System (ADS)

A flat-plate solar collector is conceived where energy cascades through thermoelectric power modules generating direct-current electricity. The intent of this work was to choose a collector configuration and to perform a steady-state thermal performance assessment. A set of energy balance equations were written and solved numerically for the purpose of optimizing collector thermal and electrical performance. The collector design involves finned columns of thermoelectric modules imbedded in the absorber plate (hot junction) over a parallel array of vertical tubes. The thermoelectric power output is limited by the small hot-junction/cold-junction temperature difference which can be maintained under steady-state conditions. The electric power per unit tube pass area is found to have a maximum as a function of a geometric parameter, while electric power is maximized with respect to an electric resistance ratio. Although the electric power efficiency is small, results indicate that there is sufficient electric power production to drive a coolant circulator, suggesting the potential for a stand-alone system.

Roberts, A. S., Jr.; Shaheen, K. E.

1982-11-01

321

Active superconductive generator development 400 horsepower generator design  

NASA Astrophysics Data System (ADS)

A superconductive acyclic generator has been designed and constructed using the unique current-carrying capabilities of superconducting wire in the field winding to produce a very high flux density in the rotor region. This, along with the use of liquid-metal current collectors in lieu of conventional brushes has yielded a very high power density machine designed to operate at gas turbine speeds. The nominal 300-kilowatt generator is 0.66 meter long and 0.46 meter in diameter (26 x 18 inches) and is designed to operate at 19,500 revolutions per minute. Extrapolation of the design analyses indicates no barriers to operation up to 750 kilowatts. Efficiencies of 98% are estimated over the practical operating range.

Stevens, H. O.; Cannell, M. J.

1981-10-01

322

KIVA-I Extended Duration MHD Generator Development.  

National Technical Information Service (NTIS)

An extended duration magnetohydrodynamic (MHD) generator system was developed. This system consists of the MHD combustor, nozzle, generator channel, diffuser, high speed data acquisition system and high voltage converter. Two steady-state generator channe...

H. W. Hehn J. K. Lytle L. W. Buechler R. A. Nimmo R. V. Shanklin

1975-01-01

323

Development of an independent type of hybrid power generation system  

Microsoft Academic Search

In this paper, the optimum control technology of an independent type of hybrid power system with wind and solar power generation, which enables a stable power supply to the loads, proposed and developed. This system comprises wind power generation inverter, solar power generation inverter, bidirectional inverter for storage batteries, and engine generator. Each inverter is connected with engine generator in

T. Hirose; H. Matsuo; Y. Ishizuka

2009-01-01

324

Study of solar-assisted thermoelectric technology for automobile air conditioning  

Microsoft Academic Search

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

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

1993-01-01

325

Application of bismuth-telluride thermoelectrics in driving DNA amplification and sequencing reactions  

Microsoft Academic Search

Recently, a new application for low-temperature thermoelectric modules has emerged in the fields of biology and medicine. Laboratory instruments that thermally cycle small biological samples for purposes of DNA amplification are now common in research laboratories throughout the world, and instruments based upon several different technologies have been developed. Market forces are increasing showing that thermoelectrics are very well suited

John Hansen; Michael Nussbaum

1996-01-01

326

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

327

Development of respiratory rhythm generation in ectothermic vertebrates  

Microsoft Academic Search

Compared with birds and mammals, very little is known about the development and regulation of respiratory rhythm generation in ectothermic vertebrates. The development and regulation of respiratory rhythm generation in ectothermic vertebrates (fish, amphibians and reptiles) should provide insight into the evolution of these mechanisms. One useful model for examining the development of respiratory rhythm generation in ectothermic vertebrates has

Michael S. Hedrick

2005-01-01

328

Thermoelectric imaging of structural disorder in epitaxial graphene  

NASA Astrophysics Data System (ADS)

Heat is a familiar form of energy transported from a hot side to a colder side of an object, but not a notion associated with microscopic measurements of electronic properties. A temperature difference within a material causes charge carriers, electrons or holes to diffuse along the temperature gradient inducing a thermoelectric voltage. Here we show that local thermoelectric measurements can yield high-sensitivity imaging of structural disorder on the atomic and nanometre scales. The thermopower measurement acts to amplify the variations in the local density of states at the Fermi level, giving high differential contrast in thermoelectric signals. Using this imaging technique, we uncovered point defects in the first layer of epitaxial graphene, which generate soliton-like domain-wall line patterns separating regions of the different interlayer stacking of the second graphene layer.

Cho, Sanghee; Kang, Stephen Dongmin; Kim, Wondong; Lee, Eui-Sup; Woo, Sung-Jae; Kong, Ki-Jeong; Kim, Ilyou; Kim, Hyeong-Do; Zhang, Tong; Stroscio, Joseph A.; Kim, Yong-Hyun; Lyeo, Ho-Ki

2013-10-01

329

Thermal System Interactions in Optimizing Advanced Thermoelectric Energy Recovery Systems  

SciTech Connect

Energy recovery is gaining importance in various transportation and industrial process applications because of rising energy costs and geopolitical uncertainties impacting basic energy supplies. Various advanced thermoelectric (TE) materials have properties that are inherently advantageous for particular TE energy recovery applications. Skutterudites, 0- and 1-dimensional quantum-well materials, and thin-film superlattice materials are providing enhanced opportunities for advanced TE energy recovery in transportation and industrial processes. This work demonstrates: 1) the potential for advanced thermoelectric systems in vehicle energy recovery, and 2) the inherently complex interaction between thermal system performance and thermoelectric device optimization in energy recovery. Potential power generation at specific exhaust temperature levels and for various heat exchanger performance levels are presented showing the current design sensitivities using different TE material sets. Mathematical relationships inherently linking optimum TE design variables and the thermal systems design (i.e., heat exchangers and required mass flow rates) are also investigated and characterized.

Hendricks, Terry J.

2007-12-01

330

Thermal System Interactions in Optimizing Advanced Thermoelectric Energy Recovery Systems  

SciTech Connect

Energy recovery is gaining importance in various transportation and industrial process applications because of rising energy costs and geopolitical uncertainties impacting basic energy supplies. Various advanced thermoelectric (TE) materials have properties that are inherently advantageous for particular TE energy recovery applications. Skutterudites, 0- and 1-dimensional quantum-well materials, and thin-film superlattice materials are providing enhanced opportunities for advanced TE energy recovery in transportation and industrial processes. This work demonstrates: 1) the potential for advanced thermoelectric systems in vehicle energy recovery, and 2) the inherently complex interaction between thermal system performance and thermoelectric device optimization in energy recovery. Potential power generation at specific exhaust temperature levels and for various heat exchanger performance levels is presented showing the current design sensitivities using different TE material sets. Mathematical relationships inherently linking optimum TE design variables and the thermal systems design (i.e., heat exchangers and required mass flow rates) are also investigated and characterized.

Hendricks, Terry J.

2007-09-01

331

Thermoelectric imaging of structural disorder in epitaxial graphene.  

PubMed

Heat is a familiar form of energy transported from a hot side to a colder side of an object, but not a notion associated with microscopic measurements of electronic properties. A temperature difference within a material causes charge carriers, electrons or holes to diffuse along the temperature gradient inducing a thermoelectric voltage. Here we show that local thermoelectric measurements can yield high-sensitivity imaging of structural disorder on the atomic and nanometre scales. The thermopower measurement acts to amplify the variations in the local density of states at the Fermi level, giving high differential contrast in thermoelectric signals. Using this imaging technique, we uncovered point defects in the first layer of epitaxial graphene, which generate soliton-like domain-wall line patterns separating regions of the different interlayer stacking of the second graphene layer. PMID:23852400

Cho, Sanghee; Kang, Stephen Dongmin; Kim, Wondong; Lee, Eui-Sup; Woo, Sung-Jae; Kong, Ki-Jeong; Kim, Ilyou; Kim, Hyeong-Do; Zhang, Tong; Stroscio, Joseph A; Kim, Yong-Hyun; Lyeo, Ho-Ki

2013-07-14

332

Slow imbalance relaxation and thermoelectric transport in graphene  

Microsoft Academic Search

We compute the electronic component (kappa) of the thermal conductivity and the thermoelectric power (alpha) of monolayer graphene, within the hydrodynamic regime, taking into account the slow rate of carrier population imbalance relaxation. Interband electron-hole generation and recombination processes are inefficient due to the non-decaying nature of the relativistic energy spectrum. As a result, a population imbalance of the conduction

Igor Aleiner; Matthew Foster

2009-01-01

333

Nonlinear thermoelectric response of quantum dots  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

334

Thermoelectric effects in silicene nanoribbons  

NASA Astrophysics Data System (ADS)

Transport and thermoelectric coefficients (including also spin thermopower) of silicene nanoribbons with zigzag edges are investigated by ab initio numerical methods. Local spin density of such nanoribbons reveals edge magnetism. As in graphene, one finds antiferromagnetic and ferromagnetic ordering, with spin polarization at one edge antiparallel or parallel to that at the other edge, respectively. Thermoelectric properties, especially the Seebeck coefficient, significantly depend on the electronic band structure and are enhanced when the Fermi level is in the energy gap. However, the thermoelectric efficiency is significantly reduced when the phonon contribution to the heat conductance is included. This phonon contribution has been calculated numerically by two different methods. Transition from antiferromagnetic to ferromagnetic states leads to a large magnetoresistance as well as to a considerable magnetothermopower. Thermoelectric parameters in the antiparallel configuration, when spin polarization in the left part of the nanoribbon is opposite to that in the right part, are also analyzed.

Zberecki, K.; Wierzbicki, M.; Barna?, J.; Swirkowicz, R.

2013-09-01

335

Effective medium theory for thermoelectrics  

NASA Astrophysics Data System (ADS)

We report on the application of effective medium theory to binary compound thermoelectric materials. We find a range of parameters for the conductivity and thermopower of the constituent elements such that the compound has an enhanced power factor. The results of effective medium theory are compared to full numerical simulations of an ensemble of disordered systems, and good qualitative agreement is found between the two calculations. The effect of various tailored geometries are explored in the direct numerical solution of the compound thermoelectrics.

Haney, Paul

2011-03-01

336

Development of Inductive Storage Pulsed Power Generators.  

National Technical Information Service (NTIS)

A pulse generator, Pawn, has been assembled at the Naval Research Laboratory. It uses inductive energy storage and opening switch power conditioning techniques with high energy density capacitors as the primary energy store. The capacitor bank stores 1 MJ...

R. J. Commisso J. R. Boller G. Cooperstein R. D. Ford P. J. Goodrich

1988-01-01

337

Surface Plasmon Coupled Nonequilibrium Thermoelectric Devices.  

National Technical Information Service (NTIS)

A surface-plasmon-coupled thermoelectric apparatus includes a first surface-plasmon substrate and a thermoelectric substrate electrically coupled to a plurality of electrodes. The substrates are electrically isolated from each other, and a first face of t...

G. Chen R. Yang A. Narayanaswamy

2004-01-01

338

Thermoelectric Power Source PP-6075( )/U.  

National Technical Information Service (NTIS)

The report describes the final design of the PP-6075(XE-2)/U Thermoelectric Power Source, which is comprised of five major functional subsystems: thermoelectric converter, liquid fuel burner, electronic circuitry, fuel system, and cooling system. Three en...

P. Stroom T. Nystrom K. Magnuson E. Pitcher

1972-01-01

339

N-type thermoelectric recycled carbon fibre sheet with electrochemically deposited Bi2Te3  

NASA Astrophysics Data System (ADS)

An N-type thermoelectric recycled carbon fibre sheet with bismuth telluride coating has been successfully synthesised through an electro-deposition technique. The Seebeck coefficient and electrical properties of the combined recycled carbon fibre sheet and bismuth telluride films are reported. Classification of the crystal structure, surface morphology and the elemental composition of the resulting deposits are methodically characterised by XRD, SEM and EDX. Cyclic voltammetry is also carried out in nitric acid solutions to investigate the right range of deposition potential. The synthesis N-type thermoelectric sheet has a highest attainable Seebeck coefficient of -54 ?V K-1 and an electrical resistivity of 8.9×10-5 ? m. The results show slight differences in morphologies and thermoelectric properties for the films deposited at varying deposition potential. The increase in thermoelectrical properties of the recycled carbon fibre is in line with the development of using coated recycled fibre for thermoelectrical applications.

Pang, E. J. X.; Pickering, S. J.; Chan, A.; Wong, K. H.; Lau, P. L.

2012-09-01

340

N-type thermoelectric recycled carbon fibre sheet with electrochemically deposited Bi2Te3  

NASA Astrophysics Data System (ADS)

An N-type thermoelectric recycled carbon fibre sheet with bismuth telluride coating has been successfully synthesised through an electrodeposition technique. The Seebeck coefficient and electrical properties of the combined recycled carbon fibre sheet and bismuth telluride films are reported. Classification of the crystal structure, surface morphology and the elemental composition of the resulting deposits are methodically characterised by XRD, SEM and EDX correspondingly. Cyclic voltammetry is also carried out in nitric acid solutions to investigate the right range of deposition potential. An N-type thermoelectric sheet was successfully synthesised with the highest attainable Seebeck coefficient of -54 ?V/k with an electrical resistivity of 8.9 × 10-5 ohm m. The results shows slight differences in morphologies and thermoelectric properties for the films deposited at varying deposition potential. The increase in thermoelectrical properties of the recycled carbon fibre is in line with the development of using coated recycled fibre for thermoelectrical applications.

Pang, E. J. X.; Pickering, S. J.; Chan, A.; Wong, K. H.

2012-06-01

341

Developments of the generative topographic mapping  

Microsoft Academic Search

The Generative Topographic Mapping (GTM) model was introduced by 7) as a probabilistic re-formulation of the self-organizing map (SOM). It oers a number of advantages compared with the standard SOM, and has already been used in a variety of applications. In this paper we report on several extensions of the GTM, including an incremental version of the EM algorithm for

Christopher M. Bishop; Markus Svensén; Christopher K. I. Williams

1998-01-01

342

Recent developments of large electrolytic hydrogen generators  

Microsoft Academic Search

The paper examines the electrolytic-hydrogen market and electrolyzers, with particular reference to general plant description, module design, auxiliary design, and basic material costs. A new design of Teledyne's Electra Cell alkaline electrolysis hydrogen generators is discussed. A major conclusion is that the highest efficiency cell may not produce the least expensive hydrogen.

J. B. Laskin; R. D. Feldwick

1976-01-01

343

Second-generation heliostat development. Final report  

SciTech Connect

The detailed design of the second-generation heliostat is presented with the supportive analyses. Component and system test data are given. The preliminary design of the manufacturing plant is described. Costs to manufacture, transport, install and maintain 50,000 heliostats per year in 50-MWe fields are projected. Cost estimates are made on a worst-case basis. (LEW)

Not Available

1981-04-01

344

Second-Generation Heliostat Development. Volume 1. Detailed Design Report.  

National Technical Information Service (NTIS)

The results of a second-generation heliostat development program completed to date are presented. This includes a presentation of the detailed design of the second-generation heliostat with the supportive analyses and component test data; preliminary desi...

L. P. Oldham

1980-01-01

345

III-nitride nanostructures for energy generation  

NASA Astrophysics Data System (ADS)

Recent developments of III-nitride materials and devices for energy applications such as photovoltaic, thermoelectric, and hydrogen generation are discussed. Although there are only few reports on InGaN based solar cells, some superior properties of this material including radiation tolerance and tunable band gap overlapping with solar spectrum considered it as a suitable candidate for space based and multijuction solar cell. Design and characterization, of InGaN based efficient p-MQW-n solar cells are presented. For the thermopower generation, we discuss the potential of InGaN alloys as thermoelectric material. Good thermoelectric materials possess low thermal conductivity and high Seebeck coefficient with high electrical conductivity. The thermal conductivity about two orders less than that of GaN and thermoelectric figure of merit as good as that of SiGe alloys are measured in In0.36Ga0.64N alloy. Our results indicate that InGaN alloys can be used to convert heat energy directly into electrical energy. Generation of hydrogen by splitting of water using InGaN alloy electrodes and solar energy via photoeletrochemical effect is also discussed.

Pantha, B. N.; Lin, J. Y.; Jiang, H. X.

2010-01-01

346

ZERO EMISSION POWER GENERATION TECHNOLOGY DEVELOPMENT  

Microsoft Academic Search

Clean Energy Systems (CES) was previously funded by DOE's ''Vision 21'' program. This program provided a proof-of-concept demonstration that CES' novel gas generator (combustor) enabled production of electrical power from fossil fuels without pollution. CES has used current DOE funding for additional design study exercises which established the utility of the CES-cycle for retrofitting existing power plants for zero-emission operations

Ronald Bischoff; Stephen Doyle

2005-01-01

347

Second-generation heliostat development. Final report  

SciTech Connect

The design, manufacture, testing and cost analysis of the second generation heliostat are described in volume I. Volume II consists of appendices of supporting material. These include the drawing tree for the heliostat, structural data of the rack assembly, drive mechanism, and mirror assemblies, tests and results, a trade study on the pedestal foundation design, cost analysis worksheets, study of an edge-support mirror module, and a study of a single-motor, differential brake heliostat drive mechanism. (LEW)

Not Available

1981-04-01

348

Second-generation heliostat development, volume 2  

NASA Astrophysics Data System (ADS)

The design, manufacture, testing and cost analysis of the second generation heliostat are described. The following topics are discussed: the drawing tree for the heliostat; structural data of the rack assembly; drive mechanism and mirror assemblies, tests and results; a trade study on the pedestal foundation design; cost analysis worksheets; study of an edge support mirror module; and a study of a single motor, differential brake heliostat drive mechanism.

1981-04-01

349

Thermoelectric Power of MnSi  

Microsoft Academic Search

The thermoelectric power of MnSi was measured from liquid He temperature to room temperature. The tangential line of thermoelectric power in the high-temperature region above TN is found not to pass the origin, in disagreement with Mott's expression. This observation is discussed in connection with the spin fluctuation in the sample, and a new expression of the thermoelectric power taking

Junji Sakurai; Yoshinori Yamamoto; Yukitomo Komura

1988-01-01

350

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

SciTech Connect

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

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

2011-01-01

351

Nanostructured thermoelectrics : big efficiency gains from small features.  

SciTech Connect

The field of thermoelectrics has progressed enormously and is now growing steadily because of recently demonstrated advances and strong global demand for cost-effective, pollution-free forms of energy conversion. Rapid growth and exciting innovative breakthroughs in the field over the last 10-15 years have occurred in large part due to a new fundamental focus on nanostructured materials. As a result of the greatly increased research activity in this field, a substantial amount of new data - especially related to materials - have been generated. Although this has led to stronger insight and understanding of thermoelectric principles, it has also resulted in misconceptions and misunderstanding about some fundamental issues. This article sets out to summarize and clarify the current understanding in this field; explain the underpinnings of breakthroughs reported in the past decade; and provide a critical review of various concepts and experimental results related to nanostructured thermoelectrics. We believe recent achievements in the field augur great possibilities for thermoelectric power generation and cooling, and discuss future paths forward that build on these exciting nanostructuring concepts.

Vineis, C. J.; Shakouri, A.; Majumdar, A.; Kanatzidis, M. G.; Materials Science Division; Northwestern Univ.; Univ.of California at Santa Cruz; Univ. of California at Berkeley

2010-01-01

352

Phase transformation and thermoelectric properties of bismuth-telluride nanowires.  

PubMed

Thermoelectric materials have attracted much attention due to the current interest in energy conversion and recent advancements in nano-engineering. A simple approach to synthesize BiTe and Bi2Te3 micro/nanowires was developed by combining solution chemistry reactions and catalyst-free vapor-solid growth. A pathway to transform the as-grown BiTe nanostructures into Bi2Te3 can be identified through the Bi-Te phase diagram. Structural characterization of these products was identified using standard microscopy practices. Meanwhile, thermoelectric properties of individual Bi-Te compound micro/nanowires were determined by the suspended microdevice technique. This approach provides an applicable route to synthesize advanced high performance thermoelectric materials in quantities and can be used for a wide range of low-dimensional structures. PMID:23619552

Hsin, Cheng-Lun; Wingert, Matthew; Huang, Chun-Wei; Guo, Hua; Shih, Ten-Jen; Suh, Joonki; Wang, Kevin; Wu, Junqiao; Wu, Wen-Wei; Chen, Renkun

2013-04-25

353

Electron-beam activated thermal sputtering of thermoelectric materials.  

SciTech Connect

Thermoelectricity and Seebeck effect have long been observed and validated in bulk materials. With the development of advanced tools of materials characterization, here we report the first observation of such an effect in the nanometer scale: in situ directional sputtering of several thermoelectric materials inside electron microscopes. The temperature gradient introduced by the electron beam creates a voltage-drop across the samples, which enhances spontaneous sputtering of specimen ions. The sputtering occurs along a preferential direction determined by the direction of the temperature gradient. A large number of nanoparticles form and accumulate away from the beam location as a result. The sputtering and re-crystallization are found to occur at temperatures far below the melting points of bulk materials. The sputtering occurs even when a liquid nitrogen cooling holder is used to keep the overall temperature at -170 C. This unique phenomenon that occurred in the nanometer scale may provide useful clues to understanding the mechanism of thermoelectric effect.

Wu, J.; He, J.; Han, M-K.; Sootsman, J. R.; Girard, S.; Arachchige, I. U.; Kanatzidis, M. G.; Dravid, V. P. (Materials Science Division); (Northwestern Univ.)

2011-08-01

354

On-chip hot spot cooling using silicon thermoelectric microcoolers  

NASA Astrophysics Data System (ADS)

Thermal management of microprocessors has become an increasing challenge in recent years because of localized high flux hot spots which cannot be effectively removed by conventional cooling techniques. This paper describes the use of the silicon chip itself as a thermoelectric cooler to suppress the hot spot temperature. A three-dimensional analytical thermal model of the silicon chip, including localized thermoelectric cooling, thermoelectric heating, silicon Joule heating, hot spot heating, background heating, and conductive/convective cooling on the back of the silicon chip, is developed and used to predict the on-chip hot spot cooling performance. The effects of hot spot size, hot spot heat flux, silicon chip thickness, microcooler size, doping concentration in the silicon, and parasitic Joule heating from electric contact resistance on the cooling of on-chip hot spots, are investigated in detail.

Wang, Peng; Bar-Cohen, Avram

2007-08-01

355

Universal scaling relations for the thermoelectric power factor of nanostructures  

NASA Astrophysics Data System (ADS)

Computational models for the transport properties of nanostructured thermoelectric materials predicted vast improvements in the thermoelectric power factor (PF) values over bulk due to discretization of the electron density-of-states function as the result of confinement. We have developed a model that bridges bulk and nanostructure PF data. The model is analyzed in the framework of the relaxation time approximation, considering different scattering mechanisms. The model shows that the PF of nanowires in fact falls below the bulk value for most of the experimentally-accessible size range. Under the constant relaxation time approximation, universal scaling relations are obtained for all single-carrier semiconductors.

Cornett, Jane E.; Rabin, Oded

2012-05-01

356

Thermoelectric transport in topological insulators  

NASA Astrophysics Data System (ADS)

Thermoelectric transport in topological insulators (TIs) is theoretically studied. TIs have gapless edge states in two dimensions, and do surface states in three dimensions. Both of the states have backscattering-free nature, and they remain gapless in the presence of nonmagnetic impurities. In particular, the edge states in two-dimensional TIs form perfect conducting channels. In this study, we calculate system-size dependence of thermoelectric properties in two-dimensional TIs, and evaluate the inelastic scattering length of the edge states by phonons, which affects the thermoelectric properties sensitively. We also study thermoelectric transport in three-dimensional (3D) TIs and compare with two dimensions. In both two- and three-dimensional TIs, there is a competition between the surface/edge and bulk transports in the thermoelectric phenomena. The surface transport in 3D TIs is relatively weak compared with the bulk transport due to impurities. Furthermore, we also study gapped 3D TIs in thin slab geometry and show large values of the figure of merit in the gapped system. This result is consistent with the previous work.

Takahashi, Ryuji; Murakami, Shuichi

2012-12-01

357

Fabrication of thermoelectric wire-matrix composites using electrodeposition  

NASA Astrophysics Data System (ADS)

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

Behnke, Joseph Frederick

358

Phase transformation and thermoelectric properties of bismuth-telluride nanowires  

NASA Astrophysics Data System (ADS)

Thermoelectric materials have attracted much attention due to the current interest in energy conversion and recent advancements in nano-engineering. A simple approach to synthesize BiTe and Bi2Te3 micro/nanowires was developed by combining solution chemistry reactions and catalyst-free vapor-solid growth. A pathway to transform the as-grown BiTe nanostructures into Bi2Te3 can be identified through the Bi-Te phase diagram. Structural characterization of these products was identified using standard microscopy practices. Meanwhile, thermoelectric properties of individual Bi-Te compound micro/nanowires were determined by the suspended microdevice technique. This approach provides an applicable route to synthesize advanced high performance thermoelectric materials in quantities and can be used for a wide range of low-dimensional structures.Thermoelectric materials have attracted much attention due to the current interest in energy conversion and recent advancements in nano-engineering. A simple approach to synthesize BiTe and Bi2Te3 micro/nanowires was developed by combining solution chemistry reactions and catalyst-free vapor-solid growth. A pathway to transform the as-grown BiTe nanostructures into Bi2Te3 can be identified through the Bi-Te phase diagram. Structural characterization of these products was identified using standard microscopy practices. Meanwhile, thermoelectric properties of individual Bi-Te compound micro/nanowires were determined by the suspended microdevice technique. This approach provides an applicable route to synthesize advanced high performance thermoelectric materials in quantities and can be used for a wide range of low-dimensional structures. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr00876b

Hsin, Cheng-Lun; Wingert, Matthew; Huang, Chun-Wei; Guo, Hua; Shih, Ten-Jen; Suh, Joonki; Wang, Kevin; Wu, Junqiao; Wu, Wen-Wei; Chen, Renkun

2013-05-01

359

Development of new generation spherical ultrasonic motor  

Microsoft Academic Search

We have successfully developed a new kind of spherical motor with two degree of freedom by ultrasonic vibration: it has ø45 rotor; the maximum speed is 30 rpm, the maximum output torque reaches 0.7 kgf cm, the maximum positioning error is less than 0.3 mm. In order to control this new motor, we have developed a new dynamic model by

Toyama Shigeki; Zhang Guoqiang; Miyoshi Osamu

1996-01-01

360

Reliable contact fabrication on nanostructured Bi2Te3-based thermoelectric materials.  

PubMed

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

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

2013-03-27

361

Feasibility survey of thermoelectric conversion technology using semiconductors  

NASA Astrophysics Data System (ADS)

The paper takes notice to thermoelectric conversion technology using semiconductors and investigates it in a wide range from high temperature to low temperature to study its feasibility. It is found that in Bi-Te alloy elements applicable to a temperature range of around 200(degree)C, some are over 3.5(times)10(sup -3)K(sup -1) in performance index, and performance of the element can be practically improved in the near future. The thermoelectric power generation system using waste heat from the fuel cell power plant, which is 5-6% in conversion efficiency, can generate output more than 100kW and is expected to improve by approximately 1% in plant overall efficiency. The construction cost, however, is around 1.6-1.9 million yen/kW. The thermoelectric power generation plant which is modeled on No.2 generator of Hatchobaru geothermal power plant can generate electric output of 10-12.5MW, which is smaller than that of the conventional geothermal power generation. The construction cost is around 3.2-4.1 million yen/kW. Even if advantage of the system in running cost is considered, attractive systematization seems to be difficult.

1993-03-01

362

Imaging radiometers employing linear thermoelectric arrays  

NASA Astrophysics Data System (ADS)

Infrared Solutions, Inc. has developed a family of radiometers which employ silicon microstructure uncooled linear thermoelectric arrays, prepared by Honeywell Technology Center. Included in the family is a handheld imaging radiometer for predictive and preventive maintenance having a frame time of 1.4 sec, a linescanner radiometer for monitoring of industrial web process, an imaging radiometer for monitoring stationary industrial processes such as a die casting, and a linescanner radiometer for monitoring the temperature distribution of railcar wheels on trains moving at speeds up to 80 mph.

McManus, Timothy; Mickelson, Steve

1999-07-01

363

Developing Generative Leadership through Emergent Learning  

Microsoft Academic Search

This thesis is the current synthesis of a deep exploration of the foundations of collaborative, transformational learning within organizations. I begin with a basic assumption which informs all the thinking that unfolds throughout this thesis: the sustainability of our organizations, and quite possibly the survival of our species, is dependent not on the leadership and the development of a chosen

Justin Sherman

1996-01-01

364

LMFBR steam generator materials development at Westinghouse  

Microsoft Academic Search

The impact of Materials and Processes (M and P) development activities at the Nuclear Components Division - Breeder Reactor Components Project of Westinghouse are described. Nine specific M and P programs have been performed over the past five years and the conclusions drawn from each are summarized herein. These engineering activities could be classified as component design, fabrication and testing

M. A. Hebbar; C. E. Sessions

1982-01-01

365

LMFBR steam generator materials development at Westinghouse  

Microsoft Academic Search

The impact of Materials and Processes (M and P) development activities at the Nuclear Components Division - Breeder Reactor Components Project of Westinghouse are described. Nine specific M and P programs have been performed over the past five years and the conclusions drawn from each are summarized herein. These engineering activities could be classified as component design, fabrication, and testing

M. A. Hebbar; C. E. Sessions

1983-01-01

366

ZERO EMISSION POWER GENERATION TECHNOLOGY DEVELOPMENT  

SciTech Connect

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

Ronald Bischoff; Stephen Doyle

2005-01-20

367

Thermoelectric refrigerator having improved temperature stabilization means  

DOEpatents

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

Falco, Charles M. (Woodridge, IL)

1982-01-01

368

Thermoelectric performance of granular semiconductors.  

SciTech Connect

We study the effects of doping and confinement on the thermoelectric properties of nanocrystalline semiconductors. We calculate the thermopower and figure of merit for temperatures less than the charging energy. For weakly coupled semiconducting grains it is shown that the figure of merit is optimized for grain sizes of order 5 nm for typical materials, and that its value can be larger than one. Using the similarities between granular semiconductors and electron or Coulomb glasses allows for a quantitative description of inhomogeneous semiconducting thermoelectrics.

Glatz, A.; Beloborodov, I. S.; Materials Science Division; California State Univ.

2009-01-01

369

An automotive thermoelectric-photovoltaic hybrid energy system  

Microsoft Academic Search

In recent years, there has been active research on exhaust gas waste heat energy recovery for automobiles. Meanwhile, the use of solar energy is also proposed to promote on-board renewable energy and hence to improve their fuel economy. In this paper, a new thermoelectric-photovoltaic hybrid energy system is proposed and implemented for automobiles. The key is to newly develop the

Xiaodong Zhang; K. T. Chau; C. C. Chan; Shuang Gao

2010-01-01

370

MEDEA II two-pulse generator development  

SciTech Connect

This article discusses improvements in the efficiency, output power, and operational flexibility of MEDEA II, a double-pulse electron beam accelerator at McDonnell Douglas Research Laboratories. A modified charging circuit, based on the triple-resonance pulse transformer concept, was implemented on both of MEDEA II's two stages. The output switches were modified to increase maximum output voltages, and a new, second output switch with asymmetric breakdown characteristics was developed. To avoid degradation of the second-pulse output waveform at the diode, a keep-alive circuit was installed. The effects of diode closure on double-pulse operation are also discussed.

Bieniosek, F.M.; Honig, J.; Theby, E.A. (McDonnell Douglas Research Laboratories, P. O. Box 516, St. Louis, Missouri 63166 (USA))

1990-06-01

371

Development of Thermocouple Generators for Small-Caliber Munitions Fuze. Phase I.  

National Technical Information Service (NTIS)

An analytical study has been performed to assess the feasibility of using aerodynamically heated thermoelectric convertors to power RF proximity fuzes. The collective results of this study indicate that such a thermoelectric power supply is feasible for u...

P. E. Eggers

1975-01-01

372

Complex half-Heusler phases as high temperature thermoelectric materials  

NASA Astrophysics Data System (ADS)

The potential of n-type MNiSn and p-type MCoSb (M=Ti, Zr, Hf) half-Heusler phases, as thermoelectric elements, for high temperature power generation applications is explored. Chapter 1 describes the background and theory behind the thermoelectric effects and physical characteristics common to promising thermoelectric materials. Chapter 2 is a review of half-Heusler alloys and their value as thermoelectric materials. In chapter 3, a description of material synthesis and thermoelectric properties characterization techniques is given. The effects of compositional changes on the thermoelectric properties of MNiSn alloys are studied and analyzed in chapter 4. In this system, Sb doping at the Sn site is shown to partially mitigate the compensated behavior observed in these materials, resulting in an increase of both the figure of merit, ZT, and the temperature at which ZT is maximized. The effects of alloying at the M and Ni sites, which modifies the band structure, resulting in changes in the electronic transport properties, and introduces phonon scattering centers, thereby decreasing the lattice thermal conductivity, are reported. In addition to the benefits of increased alloying at the M site, on the thermal conductivity and thermoelectric transport properties, chapter 5 also presents an examination of Sn substitution on the Sb sublattice of MCoSb. This substitution is shown to transition these materials from semimetals to robust n-type and p-type thermoelectric materials. The significant lack of p-type thermoelectric materials, which operated at temperature above 700°C, make these materials appealing for study. In chapter 6, the effect of alloy and boundary scattering on the high temperature lattice thermal conductivity is also studied and analyzed. Alloy scattering at high temperature is analyzed using the Klemens-Callaway model, while a model for boundary scattering from grains, is adapted from the work of Sharp, Poon, and Goldsmid. These models are found to be effective tools for prediction of the high temperature lattice thermal conductivity and are used to explain the anomalous upturn observed in the lattice thermal conductivity at temperatures above 900K. It is found from these models and experiment that the effectiveness of alloy and boundary scattering, for reduction of the thermal conductivity, is diminished at elevated temperatures. Thus, it is necessary to explore other phonon scattering mechanisms that can further reduce the lattice thermal conductivity while maintaining the promising electronic transport properties of these materials. The thermoelectric figure of merit for select Sb-doped MNiSn alloys are found to reach ZT?0.8 at T?800°C, while the not-yet-optimized MCoSb phases realize ZT?0.5 at 1000K (measured) and ZT?0.6 at 1100K (extrapolated). These values meet or exceed the industry benchmarks for high temperature thermoelectric materials, set by SiGe alloys.

Culp, Slade Roland

373

Thermoelectrically Controlled Spin-Switch  

Microsoft Academic Search

The search for novel spintronic devices brings about new ways to control switching in magnetic thin-films. In this work we experimentally demonstrate a device based on thermoelectrically controlled exchange coupling. The read out signal from a giant magnetoresistance element is controlled by exchange coupling through a weakly ferromagnetic Ni-Cu alloy. This exchange coupling is shown to vary strongly with changes

S. Andersson; V. Korenivski

2010-01-01

374

IRCCD cooled with thermoelectric cooler  

Microsoft Academic Search

For a low cost approach, thermoelectric coolers have often been thought of because of their solid state structure offering low fabrication cost and zero maintenance for cooling down detectors sensitive in the 3 to 5 micrometers spectral band. The performance of such detection assemblies is highly dependent on the achievable cold temperature due to the contribution of dark current in

Louis-Pascal Angebault; Nicolas Gerin; Pierre Maze; Michel Vuillermet

1994-01-01

375

Development and Test of a Prototype 100MVA Superconducting Generator  

SciTech Connect

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

Fogarty, James M.; Bray, James W.

2007-05-25

376

Development of a Cantilever Beam Generator Employing Vibration Energy Harvesting  

Microsoft Academic Search

This paper details the development of a generator based upon a cantilever beam inertial mass system which harvests energy from ambient environmental vibrations. The paper compares the predicted results from Finite Element Analysis (FEA) of the mechanical behaviour and magnetic field simulations and experimental results from a generator. Several design changes were implemented to maximise the conversion of magnetic energy

R. N. Torah; S. P. Beeby; M. J. Tudor; T. O'Donnell; S. Roy

377

Next-generation digital camera integration and software development issues  

Microsoft Academic Search

This paper investigates the complexities associated with the development of next generation digital cameras due to requirements in connectivity and interoperability. Each successive generation of digital camera improves drastically in cost, performance, resolution, image quality and interoperability features. This is being accomplished by advancements in a number of areas: research, silicon, standards, etc. As the capabilities of these cameras increase,

Shyam Venkataraman; Richard Hecht; Ken Peters

1998-01-01

378

Second-generation heliostat development. Volume 1: Detailed design report  

Microsoft Academic Search

The results of a second generation heliostat development program are presented. This includes: (1) a presentation of the detailed design of the second generation heliostat with the supportive analyses and component test data; (2) preliminary design of the manufacturing plant; and (3) the projected cost to manufacture, transport, install, and maintain 50,000 heliostats per year installed in 50 MWe fields.

L. P. Oldham

1980-01-01

379

A new thermoelectric alloy for cooling applications  

NASA Astrophysics Data System (ADS)

In the last twenty years no improvements in bulk materials has been achieved for cooling in the thermoelectrics industry that has surpassed the cooling capabilities of the alloys developed at RCA by Yim and Rosi. In that work they achieved a DeltaT of 77.6K from room temperature. This work focuses on the development of a new n-type and improving the p-type alloy from the Bisb2Tesb3-Sbsb2Tesb3-Sbsb2Sesb3 pseudo-ternary alloy system. Improvements in the alloy have allowed the construction of a cooling device that achieves a DeltaT of 79.2K. In bulk material growth the highest figure of merit material, Z, for room temperature cooling applications is a p-type material (Bisb2Tesb3)sb{25}(Sbsb2Tesb3)sb{72}(Sbsb2Sesb3)sb3 that has a Z = 3.6× 10sp{-3}/K and an n-type material (Bisb2Tesb3)sb{90}(Sbsb2Tesb3)sb5(Sbsb2Sesb3)sb5 with a Z = 3.2× 10sp{-3}/K developed at the University of Virginia. The present work improves on these results by developing a new n-type material (Bisb2Tesb3)sb{70}(Sbsb2Tesb3)sb{25}(Sbsb2Sesb2)sb5 with a Z = 3.4× 10sp{-3}/K. The improvement in this new alloy is due to a lower thermal conductivity with equivalent electrical properties to the old n-type alloy (Bisb2Tesb3)sb{90}(Sbsb2Tesb3)sb5(Sbsb2Sesb3)sb5. The temperature dependent properties from 250K-400K of the three alloys with various dopant concentrations was measured to study temperature effects on the thermoelectric properties. Studies were also conducted on ohmic contacts, including measuring the contact resistivity size and the resistivity of the solder. The contact resistivity is an effect that is critical to device performance in small modules. This work also found that the dopant material is relevant to the overall thermoelectric properties of the alloy. In the p-type material (Bisb2Tesb3)sb{25}(Sbsb2Tesb3)sb{72}(Sbsb2Sesb3)sb3 the figure of merit was lowered when SbIsb3 was used instead of Te as a compensator of excess holes. This effect was not apparent in the new n-type alloy (Bisb2Tesb3)sb{70}(Sbsb2Tesb3)sb{25}(Sbsb2Sesb3)sb5. Using the measured temperature dependent properties an improved finite difference model was constructed to evaluate the thermoelectric material. This model improved upon previous models by including the Thomson coefficient and resistance due to the contacts and the metal junctions. This model predicted the maximum cooling of the given thermoelectric material to within 3K of the actual device. Older models based on material parameters either overestimated the cooling by 5K or underestimated it by 3.5K.

Ettenberg, Martin Harris

380

Research and development of fuel cell generation technology  

NASA Astrophysics Data System (ADS)

Low-temperature, low-pressure phosporic-acid fuel-cell power generation systems are being developed, as are matrix and paste electrolyte type molten-carbonate fuel-cell pilots plants. System analyses are also reported.

1985-04-01

381

Thermoelectric infrared imager and automotive applications  

NASA Astrophysics Data System (ADS)

This paper describes a newly developed thermoelectric infrared imager having a 48 X 32 element thermoelectric focal plane array (FPA) and an experimental vehicle featuring a blind spot pedestrian warning system, which employs four infrared imagers. The imager measures 100 mm in width, 60 mm in height and 80 mm in depth, weighs 400 g, and has an overall field of view (FOV) of 40 deg X 20 deg. The power consumption of the imager is 3 W. The pedestrian detection program is stored in a CPU chip on a printed circuit board (PCB). The FPA provides high responsivity of 2,100 V/W, a time constant of 25 msec, and a low cost potential. Each element has external dimensions of 190 micrometer X 190 micrometer, and consists of six pairs of thermocouples and an Au-black absorber that is precisely patterned by low-pressure evaporation and lift-off technologies. The experimental vehicle is called the Nissan ASV-2 (Advanced Safety Vehicle-2), which incorporates a wide range of integrated technologies aimed at reducing traffic accidents. The blind spot pedestrian warning system alerts the driver to the presence of a pedestrian in a blind spot by detecting the infrared radiation emitted from the person's body. This system also prevents the vehicle from moving in the direction of the pedestrian.

Hirota, Masaki; Satou, Fuminori; Saito, Masanori; Kishi, Youichi; Nakajima, Yasushi; Uchiyama, Makato

2001-10-01

382

Study on iron disilicide thermoelectric generator  

NASA Astrophysics Data System (ADS)

The first objective of the experimental work is to verify the characteristics of commercially available material. The Japanese company Komatsu Electronics Ltd., sells U-Shaped couples of FeSi2. Twenty-four couples are now in our laboratory. Each leg of the couple is made of one type (N or P) of material and the junction is placed directly into a flame. Being almost impossible to measure the hot junction temperature in the flame and to evaluate the heat flux going through the material between hot and cold junctions, we have designed an experimental assembly, suited to measure these values. The main problem is to obtain a good thermal contact for the hot junctions. If not, there is an important temperature drop between the hot source and the hot junction of the couple leading to wrong values of the characteristics.

Anderson, Gerald

1987-11-01

383

Thermoelectric generator with hinged assembly for fins  

DOEpatents

A cylindrical casing has a central shielded capsule of radioisotope fuel. A plurality of thermonuclear modules are axially arranged with their hot junctions resiliently pressed toward the shield and with their cold junctions adjacent a transition member having fins radiating heat to the environment. For each module, the assembly of transition member and fins is hinged to the casing for swinging to permit access to and removal of such module. A ceramic plate having gold layers on opposite faces prevents diffusion bonding of the hot junction to the shield.

Purdy, David L. (Indiana, PA); Shapiro, Zalman M. (Pittsburgh, PA); Hursen, Thomas F. (Pittsburgh, PA); Maurer, Gerould W. (Apollo, PA)

1976-11-02

384

LMFBR steam generator development: duplex bayonet tube steam generator. Volume II  

Microsoft Academic Search

This report represents the culmination of work performed in fulfillment ;\\u000a of ERDA Contract AT(11-1)-2426, Task Agreement 2, in which alternate steam ;\\u000a generator designs were developed and studied. The basic bayonet tube generator ;\\u000a design previously developed by C-E under AEC Contract AT(11-1)-3031 was expanded ;\\u000a by incorporating duplex heat transfer tubes to enhance the unit's overall safety ;

DeFur

1975-01-01

385

Lossless hybridization between photovoltaic and thermoelectric devices  

NASA Astrophysics Data System (ADS)

The optimal hybridization of photovoltaic (PV) and thermoelectric (TE) devices has long been considered ideal for the efficient harnessing solar energy. Our hybrid approach uses full spectrum solar energy via lossless coupling between PV and TE devices while collecting waste energy from thermalization and transmission losses from PV devices. Achieving lossless coupling makes the power output from the hybrid device equal to the sum of the maximum power outputs produced separately from individual PV and TE devices. TE devices need to have low internal resistances enough to convey photo-generated currents without sacrificing the PV fill factor. Concomitantly, a large number of p-n legs are preferred to drive a high Seebeck voltage in TE. Our simple method of attaching a TE device to a PV device has greatly improved the conversion efficiency and power output of the PV device (~30% at a 15°C temperature gradient across a TE device).

Park, Kwang-Tae; Shin, Sun-Mi; Tazebay, Abdullah S.; Um, Han-Don; Jung, Jin-Young; Jee, Sang-Won; Oh, Min-Wook; Park, Su-Dong; Yoo, Bongyoung; Yu, Choongho; Lee, Jung-Ho

2013-07-01

386

Combustion Synthesis of Doped Thermoelectric Oxides  

SciTech Connect

Self-propagating high-temperature synthesis (SHS) was used to prepare silver doped calcium cobaltates (Ca1.24- xAgxCo1.62O3.86, x = 0.03 - 0.12) powders. SHS is a simple and economic process to synthesize ceramic materials with minimum energy requirements. The heat generated by the SHS reaction can sustain the propagation of the reaction front and convert reactants to desired products. The effect of doping level on thermoelectric properties was investigated in this study. Results show the substitution of calcium by silver decreases the thermal conductivity significantly. XRD and surface area measurements show synthesized powders are phase pure and have large specific surface areas.

Selig, Jiri [Lamar University; Lin, Sidney [Lamar University; Lin, Hua-Tay [ORNL; Johnson, D Ray [ORNL

2012-01-01

387

Efficiency of thermoelectric recuperators of the exhaust gas energy of internal combustion engines  

NASA Astrophysics Data System (ADS)

Results of computer simulation of thermoelectric generators (TEG) using the exhaust heat of internal combustion engines are presented. Sectionalized generator schematics whereby maximum efficiency is achieved for cases of real temperature dependences of the most suitable thermoelectric materials are considered. A model optimized for minimum cost is considered as well. Results of experimental research on generator that employs exhaust heat from heat and electricity cogeneration plant with a diesel engine are presented. Computer simulation is verified by the test results. The outlook for application of such heat recuperators in stationary plants is considered.

Anatychuk, L. I.; Kuz, R. V.; Rozver, Yu. Yu.

2012-06-01

388

In-Situ Growth of Yb2O3 Layer for Sublimation Suppression for Yb14MnSb11 Thermoelectric Material for Space Power Applications.  

National Technical Information Service (NTIS)

The compound Yb14MnSb11 is a p-type thermoelectric material of interest to the National Aeronautics and Space Administration (NASA) as a candidate replacement for the state-of-the-art Si-Ge used in current radioisotope thermoelectric generators (RTGs). Id...

E. J. Opila J. A. Nesbitt M. V. Nathal

2012-01-01

389

Thermoelectric materials and chalcogenide compounds  

US Patent & Trademark Office Database

A thermoelectric material is disclosed. The thermoelectric material is represented by the following formula; (A.sub.1-aA'.sub.a).sub.4-x(B.sub.1-bB'.sub.b).sub.3-y. A is a Group XIII element and A' may be a Group XIII element, a Group XIV element, a rare earth element, a transition metal, or combinations thereof. A and A' are different from each other. B may be S, Se, Te and B' may be a Groups XIV, XV, XVI or combinations thereof. B and B' are different from each other. a is equal to or larger than 0 and less than 1. b is equal to or larger than 0 and less than 1. x is between -1 and 1 and wherein y is between -1 and 1.

Rhyee; Jong-soo (Suwon-si, KR); Lee; Sang-mock (Yongin-si, KR)

2012-10-30

390

Fabrication of Nanocomposite Thermoelectric Materials by a Pulsed Laser Deposition Method  

NASA Astrophysics Data System (ADS)

We applied a pulsed laser deposition (PLD) technique to fabricate nanocomposite half-Heusler thermoelectrics by employing two different methods: a dry process and a wet process. First, we tried to obtain nanosized thermoelectric particles by using PLD in a liquid solvent. Nanosized (<100 nm) spherical and crystalline half-Heusler particles containing Ti, Zr, Hf, Ni, and Sn elements were obtained by this method, showing good controllability of stoichiometry. The key is to select a solvent that prevents oxidation. Second, the dry PLD process was employed to coat the thermoelectric powder with metal oxides. To this end, we developed a PLD coating apparatus. After sintering the coated powder using the spark plasma sintering (SPS) technique, we confirmed that a nanosized layer of the metal oxides was uniformly formed at the grain boundaries of the half-Heusler matrix. With these two examples, the capability of the PLD techniques to fabricate well-controlled nanocomposite thermoelectric materials is demonstrated.

Matsubara, Masato; Azuma, Hirozumi; Asahi, Ryoji

2011-05-01

391

Thermoelectric power of metallic Rb3C60: phonon-drag and carrier diffusion contributions  

NASA Astrophysics Data System (ADS)

Thermoelectric power ( S) of Rb3C60 fullerides in the metallic phase is theoretically estimated. We first develop a Hamiltonian model that incorporates the scattering rates within the relaxation time approximation to estimate the phonon-drag thermoelectric power ( S ph drag) incorporating the scattering of phonons with defects, electrons as carriers, grain boundaries, and phonon-phonon interactions. As a next step, Mott expression within parabolic band approximation is used to analyze the electron diffusive thermoelectric power ( S c diff) using Fermi energy as electron parameter, and S c diff shows a linear temperature dependence. The S ph drag is nonzero in both normal and superconducting states. Its behavior is determined by competition among the several operating scattering rates for heat carriers and a balance between diffusive carrier and phonon-drag contributions. Acoustic phonons are effectively scattered by various scatterers for the thermoelectric power. S infers a change in slope above transition temperature and becomes almost linear above 70 K.

Varshney, Dinesh; Singh, Namita

2012-11-01

392

Thermoelectric power of metallic Rb3C60: phonon-drag and carrier diffusion contributions  

NASA Astrophysics Data System (ADS)

Thermoelectric power ( S) of Rb3C60 fullerides in the metallic phase is theoretically estimated. We first develop a Hamiltonian model that incorporates the scattering rates within the relaxation time approximation to estimate the phonon-drag thermoelectric power ( S ph drag) incorporating the scattering of phonons with defects, electrons as carriers, grain boundaries, and phonon-phonon interactions. As a next step, Mott expression within parabolic band approximation is used to analyze the electron diffusive thermoelectric power ( S c diff) using Fermi energy as electron parameter, and S c diff shows a linear temperature dependence. The S ph drag is nonzero in both normal and superconducting states. Its behavior is determined by competition among the several operating scattering rates for heat carriers and a balance between diffusive carrier and phonon-drag contributions. Acoustic phonons are effectively scattered by various scatterers for the thermoelectric power. S infers a change in slope above transition temperature and becomes almost linear above 70 K.

Varshney, Dinesh; Singh, Namita

2012-12-01

393

Interfacial effects on thermoelectric functions  

Microsoft Academic Search

We investigated the effects of added oxide to FeSi2 on thermoelectric properties in order to improve the figure of merit. The oxide was not suggested to chemically react with\\u000a the mother material (FeSi2), where the oxide materials existed in the grain boundaries. The oxide addition played a role to reduce thermal conductivity\\u000a and possessed electrical resistivity as well as non

S. Mochizuki; S. Sugihara; T. Nakamura; H. Akimoto

2001-01-01

394

Thermoelectric refrigerator for gas analyzer  

Microsoft Academic Search

The authors describe a thermoelectric refrigerator for an air analyzer which cools an airstream by 24-30.4 K for a flow rate of 0.3 m³\\/h and a power consumption of less than or equal to 33.2 W. The setup time is 45 minutes. This refrigerator makes it possible to increase the average temperature of the heat-absorbing junction of the thermopile and

G. V. Bochin; V. I. Butyrskii; L. N. Karaseva

1987-01-01

395

Summary of DEEP STEAM Downhole Steam Generator Development Activities.  

National Technical Information Service (NTIS)

In this paper the concept and goals of the DOE program, DEEP STEAM, as related to the development of a downhole steam generator for deep heavy oil recovery will be discussed. Additionally, the past, present and future activities of the development program...

A. B. Donaldson A. J. Mulac R. L. Fox

1981-01-01

396

The paradox of gifted leadership: developing the generation of leaders  

Microsoft Academic Search

Purpose – The purpose of this paper is to highlight the paradox of gifted leadership – namely that executives who are gifted in leading their organizations may not be able to develop leaders under them – creating a challenge in developing the next generation of leaders. Design\\/methodology\\/approach – To help confront this paradox the paper highlights insights for how executives

Pete Hammett

2008-01-01

397

Analysis of fault generation caused by stress during software development  

Microsoft Academic Search

The effects of stress on fault generation in both structured and functional design methodologies during software development were quantitatively determined through a controlled experiment. Two teams developed the same software program under the same stressed conditions, except for design methodologies. The degree of stress was measured by inner metrics we proposed. The results of the analysis show that (1) the

Tsuneo Furuyama; Yoshio Arai; Kazuhiko Iio

1997-01-01

398

Inspirational leadership: involving senior leaders in developing the next generation  

Microsoft Academic Search

Purpose – The purpose of this paper is to share the successful experience of Lilly Research Laboratories (LRL) in engaging senior leaders in developing the next generation of leaders. Design\\/methodology\\/approach – The paper describes the principles and approach used by LRL. It provides a straightforward description of the major leadership development programs with a more detailed description of a course

Jack Harris; B. Kim Barnes

2006-01-01

399

SOFRADIR second-generation IRFPA technology: recent developments  

Microsoft Academic Search

Sofradir has developed a series of products by using the second generation IRFPA technology developed by the French research laboratory Lir with the support of the French MoD. This technology is based on the use of MCT photovoltaic diodes coupled to silicon readout circuit thanks to indium bump technique. The maturity is so good that producibility of such high performance,

Jean-Pierre Chatard

1994-01-01

400

Comparison of different pressing techniques for the preparation of n-type silicon-germanium thermoelectric alloys  

SciTech Connect

Improvements to state-of-the-art Si{sub 80}Ge{sub 20} thermoelectric alloys have been observed in laboratory-scale samples by the powder metallurgy techniques of mechanical alloying and hot pressing. Incorporating these improvements in large scale compacts for the production of thermoelectric generator elements is the next step in achieving higher efficiency RTGs. This paper discusses consolidation of large quantities of mechanically alloyed powders into production size compacts. Differences in thermoelectric properties are noted between the compacts prepared by the standard technique of hot uniaxial pressing and hot isostatic pressing. Most significant is the difference in carrier concentration between the alloys prepared by the two consolidation techniques.

Harringa, J.L.; Cook, B.A.

1996-06-01

401

Thermoelectric Properties of Graphene Ribbons  

NASA Astrophysics Data System (ADS)

Several theoretical and experimental studies have been recently concerned with electric and thermal transport in graphene layers and ribbons, where propagation of electrons [1] and phonons [2] seems to be dominated by a ballistic mechanism. Of particular interest in this context is the identification and characterization of thermoelectric effects [3], which represent a promising alternative for energy recovery in technological applications. In the present work, the effect of the electron- phonon interaction over a predominantly ballistic transport mechanism in graphene ribbons is studied in the context of thermoelectricity. Theoretical estimations of the thermopower S, and the corresponding figure of merit ZT, are presented for this system as a function of temperature. [4pt] [1] K. Saito, J. Nakamura, and A. Natori, "Ballistic thermal conductance of a graphene sheet," Phys. Rev. B 76, 115409 (2007).[0pt] [2] E. Munoz, J. Lu, and B. I. Yakobson, "Ballistic thermal conductance of graphene ribbons," Nano Lett. 10, 1652 (2010).[0pt] [3] Y. Ouyang and J. Guo, "A theoretical study on thermoelectric properties of graphene nanoribbons," Appl. Phys. Lett. 94, 263107 (2009).

Munoz, Enrique

2011-03-01

402

Development of the fuel cell power generation technology, 2  

NASA Astrophysics Data System (ADS)

NEDO arranged results of the research on the development of the fuel cell power generation technology during fiscal 1981 to 1987. During 1981 to 1983, research and development were made on a dispersed generation type fuel cell power generation system using phosphoric acid fuel cells (low temperature/pressure type) and a thermal power plant substitution type fuel cell power generation system (high temperature/pressure type). During 1984 to 1986, in addition to the above, research was made on a total system of phosphoric acid fuel cells, trial operation of a molten carbonate fuel cell power plant (matrix electrolyte method, paste electrolyte method) and a total system. In 1987, as to molten carbonate fuel cells, researches were made on stacks and a peripheral system, support, and a total system. As a comprehensive technology development of phosphoric acid fuel cells, researches were made on a fuel cell power generation system for isolated island use and a fuel cell power generation system for business use.

1994-02-01

403

A study on thermoelectric properties of nanostructured bulk materials  

NASA Astrophysics Data System (ADS)

Solid-state cooling and power generation based on thermoelectric effects are attractive for a wide range of applications in power generation, waste heat recovery, air-conditioning, and refrigeration. There have been persistent efforts on improving figure of merit (ZT) since 1950's, but the ZTs of dominant commercial bulk materials have been remained at ˜1. To improve ZT to a higher value, we have been pursuing an approach based on random nanostructures, based on the idea that the thermal conductivity reduction that is responsible for ZT enhancement in superlattices can be realized in such nanostructures. In this dissertation I will discuss synthesis and characterization of various nanopowders prepared by chemical as well as high-energy ball milling methods. The solid dense samples from nanopowders were prepared by direct current induced hot press (DC hot press) technique. The thermoelectric properties of the hot pressed samples have been studied in detail. In our study, ZT values of ˜1.4 and ˜1.2 have been achieved in bulk p- and n-type bismuth telluride alloys respectively. More importantly, in the range of 20--250°C, ZT is above 0.8 with a peak ZT of 1.4 at 100°C in p-type sample, which makes it not only very useful for cooling but also very efficient for power generation with hot side close to 250°C, an efficiency not attainable before due to a reduction in ZT to below 0.25 at that temperature. Power generation efficiency and cooling performance using our hot-pressed samples show better performance than the commercially available samples of these materials. These bulk materials were made by DC hot press technique using nanopowders prepared by high energy ball milling. Microstructure studies and theoretical analysis indicated that the improvement mainly comes from a lower phonon contribution to thermal conductivity due to increased boundaries and defect states. Lead telluride, lead selenide and their alloys using a similar approach have also been studied. In p- and n-type alloys of PbSnTe and AgPbSbTe, ZTs higher than the state-of-the-art PbTe alloys are obtained. The discovery points a new direction to achieve higher ZT in other thermoelectric bulk materials, which we believe will change the thermoelectric energy conversion technology landscape. With the data we obtained, it is clear that a nanoparticle based thermoelectric materials hold significant promise. We already have demonstrated enhanced ZT values in various nanostructured materials and demonstrated the feasibility of the approach. We believe that continued investigation in this area should let us achieve superlattice-like figures of merit, based on these results.

Poudel, Bed

404

Heat reflecting tape for thermoelectric converter  

DOEpatents

Threads are interlaced with thermoelectric wires to provide a woven cloth in tape form, there being an intermediate layer of heat radiation reflecting material (e.g., aluminum foil) insulated electrically from said wires, which are of opposite thermoelectric polarity and connected as a plurality of thermocouples.

Purdy, David L. (Indiana, PA)

1977-01-01

405

Thermoelectric effect on electroosmotic flow in microchannel  

Microsoft Academic Search

The present work reports the thermoelectric effect on electroosmotic flow (EOF) in microchannel. The thermoelectric (TE) effect on EOF was analyzed and the switch process of fluids controlled by TE unit was numerically simulated. The mathematical model was established that is composed with electrokinetics fluid, liquid-solid phase transition, and heat transfer. The microfluidic chip with the integrated TE unit was

Zheng Xu; Xiao-yu Yu; Li-qun Du; Lun-lei Yang; Chong Liu; Li-ding Wang

2009-01-01

406

Influence of dimensionality on thermoelectric device performance  

Microsoft Academic Search

The role of dimensionality on the electronic performance of thermoelectric devices is clarified using the Landauer formalism, which shows that the thermoelectric coefficients are related to the transmission, T(E), and how the conducting channels, M(E), are distributed in energy. The Landauer formalism applies from the ballistic to diffusive limits and provides a clear way to compare performance in different dimensions.

Raseong Kim; Supriyo Datta; Mark S. Lundstrom

2009-01-01

407

State of the art in solar thermoelectric power plant research  

NASA Astrophysics Data System (ADS)

World wide research efforts to develop multi-MW solar central receiver thermoelectric power plants are outlined, noting that only this form of solar energy, coupled with storage, permits adjusting output to meet loads. Among the systems described, which are all heliostat-tower configurations, are the 500 kWe SSPS-CRS of the IEA located in southern Spain, the Eurelios station producing 1 MWe on Sicily, and the 1 MWe CESA-1 plant at Tabernas, Spain. Descriptions are also given of the 1 MWe installation at Nio, Japan, the Themis project in France with an output of 2000-2500 MWe, the Soviet CES-5 5 MWe power plant in Lenino on the shore of the Sea of Azov, and the 10 MWe Solar-1 project in Barstow, CA. The systems employ hot air, steam, sodium, or fused salt as heat exchanger fluids, and are being tested for use in producing grid-quality electricity, industrial heat, combustible liquids, and to repower fossil-fuel fed generator cycles.

Etievant, C.

408

Thermoelectricity in Self-Contained Heating and Boiler Systems  

NASA Astrophysics Data System (ADS)

The use of thermoelectric generators (TEGs) in heating systems enables autonomous supply of power to automatic safety devices, creation of optimized gas mixtures, and automation and precise temperature control of exhaust gas and heat carriers. It is particularly important to make heating systems independent of the district electric grid. Results of research and development efforts on a TEG for supplying power to electric devices of self-contained heating and boiler systems are presented. A TEG physical model is proposed, and results of computer simulation and optimization of its basic power and design parameters are given. Two TEG design variants (single and double sided) are considered. Their advantages and shortcomings are discussed. On the basis of theoretical calculations, a prototype TEG for a 10.5-kW boiler is built. At water heating system temperatures from 35°C to 80°C, the TEG electric power is 50 W to 65 W, which is used to supply a circulation pump for forced liquid heat carrier delivery (30 W to 40 W) and a fan for removal of fuel combustion products from the boiler’s smoke chamber (5 W to 7 W).

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

2010-09-01

409

Thermoelectric properties of electrolessly etched silicon nanowire arrays  

NASA Astrophysics Data System (ADS)

Patterning silicon as nanowires with roughened sidewalls enhances the thermoelectric figure-of-merit ZT by order of magnitude compared to the bulk at 300 K [1]. The enhancement is mainly achieved by the remarkable reduction in the thermal conductivity below 5 W/mK at 300 K with only a negligible effect on the power factor of these nanowires. While the focus remained on understanding the implications of surface disorder on the thermal conductivity, the phonon transport effects on the Seebeck coefficient of these wires remains largely unexplored. We developed an electroless etching technique to generate nanowire arrays (NWAs) with controlled surface roughness, morphology, porosity and doping [2]. We conduct the simultaneous device-level measurements of the Seebeck coefficient and thermal conductivity of the NWAs using frequency domain techniques. We observe that nano-structuring quenches the phonon drag [3] in NWAs thereby reducing the Seebeck coefficient by ˜25% compared to the bulk at degenerate doping levels. Further, we observe that the sidewall roughness greater than 3 nm roughness height lowers the thermal conductivity 75% below the Casimir limit [4] with 10% - 15% increase in Seebeck coefficient. The porous NWAs show thermal conductivity close to the amorphous limit of Si with enhancement in the Seebeck coefficient primarily due to the carrier depletion. References: [1] A. I. Hochbaum et al, Nature 451, 163-167 (2008). [2] K. Balasundaram et. al., Nanotechnology 23, 305304 (2012). [3] C. Herring, Phys. Rev. 96, 1163 (1954). [4] H. G. B. Casimir, Physica 5, 495 (1938).

Sadhu, Jyothi; Tian, Hongxiang; Ma, Jun; Valavala, Krishna; Singh, Piyush; Sinha, Sanjiv

2013-03-01

410

Thermoelectric power source utilizing ambient energy harvesting for remote sensing and transmitting  

SciTech Connect

A method and apparatus for providing electrical energy to an electrical device wherein the electrical energy is originally generated from temperature differences in an environment having a first and a second temperature region. A thermoelectric device having a first side and a second side wherein the first side is in communication with a means for transmitting ambient thermal energy collected or rejected in the first temperature region and the second side is in communication with the second temperature region thereby producing a temperature gradient across the thermoelectric device and in turn generating an electrical current.

DeSteese, John G

2010-11-16

411

Thermal Conductivity Measurements of Bulk Thermoelectric Materials (Prop. 2004-067)  

SciTech Connect

Thermal conductivity is an important material property of the bulk thermoelectrics. To improve ZT a reduced thermal conductivity is always desired. However, there is no standard material for thermoelectrics and the test results, even on the same material, often show significant scatter. The scatter in thermal conductivity made reported ZT values uncertain and sometime unrepeatable. One of the reasons for the uncertainty is due to the microstructure differences resulting from sintering, heat treatment and other processing parameters. They selected commonly used bulk thermoelectric materials and conducted thermal conductivity measurements using the laser flash diffusivity and differential scanning calorimeter (DSC) systems. Thermal conductivity was measured as a function of temperature of temperature from room temperature to 500 K and back to room temperature. The effect of thermal cycling on the bulk thermoelectric was studied. Comnbined with measurements on electrical resistivity and Seebeck coefficient, they show the use of a ZT map in selecting thermoelectrics. The commercial bulk material showed very good consistency and reliability compared to other bulk materials. The goal is to develop a thermal transport properties database for the bulk thermoelectrics and make the information available to the research community and industry.

Wang, Hsin [ORNL; Porter, Wallace D [ORNL; Sharp, J [Marlow Industries, Inc

2006-01-01

412

Development of droplet generator for liquid droplet radiator  

NASA Astrophysics Data System (ADS)

A single-nozzle liquid droplet generator was fabricated and tested as part of a program aimed at the development of a liquid droplet generator for the liquid droplet radiator (LDR). The droplet generator uses diffusion pump oil as the working fluid. The pressurized oil is squirted from an orifice in the form of a liquid jet which is perturbed by an electrically driven oscillating piezoceramic disk. The growing oscillations eventually break up the liquid jet, and the droplets are formed with the same frequency as the oscillation. Results of vacuum chamber tests of the droplet generator indicate that the droplet velocity, droplet diameter, and the spacing between adjacent droplets satisfy the LDR design requirements.

Hosokawa, Shunsuke; Kawada, Masakuni; Iwasaki, Akira; Kudo, Isao

413

[Next generation sequencing technologies (NGST) -- development and applications].  

PubMed

In the past ten years the development of next generation sequencing technologies brought a new era in the field of quick and efficient DNA sequencing. In our study we give an overview of the methodological achievements from Sanger's chain-termination sequencing in 1975 to those allowing real-time DNA sequencing today. Sequencing methods that utilize clonal amplicons for parallel multistrand sequencing comprise the basics of currently available next generation sequencing techniques. Nowadays next generation sequencing is mainly used for basic research in functional genomics, providing quintessential information in the meta-analyses of data from signal transduction pathways, onthologies, proteomics and metabolomics. Although next generation sequencing is yet sparsely used in clinical practice, cardiology, oncology and epidemiology already show an immense need for the additional knowledge obtained by this new technology. The main barrier of its spread is the lack of standardization of analysis evaluation methods, which obscure objective assessment of the results. PMID:21177232

Mihály, Zsuzsanna; Gyorffy, Balázs

2011-01-01

414

Atomic-level cotrol of the thermoelectric properties in polytypoid nanowires  

SciTech Connect

Thermoelectric materials have generated interest as a means of increasing the efficiency of power generation through the scavenging of waste heat. Materials containing nanometer-sized structural and compositional features can exhibit enhanced thermoelectric performance due to the decoupling of certain electrical and thermal properties, but the extent to which these features can be controlled is often limited. Here we report a simple synthesis of M{sub 2}O{sub 3}(ZnO){sub n} (M = In, Ga, Fe) nanowires with controllable polytypoid structures, where the nanostructured features are tuned by adjusting the amount of metal precursor. After the introduction of nanometer-scale features (individual atomic layers and alloying), thermal and electrical measurements on single In{sub 2-x}Ga{sub x}O3(ZnO){sub n} nanowires reveal a simultaneous improvement in all contributing factors to the thermoelectric figure of merit, indicating successful modification of the nanowire transport properties.

Andrews, Sean C.; Fardy, Melissa A.; Moore, Michael C.; Aloni, Shaoul; Zhang, Minjuan; Radmilovic, Velimir; Yang, Peidong

2010-10-23

415

Development of a renewable hybrid power generation system  

Microsoft Academic Search

A renewable hybrid power generation system is proposed. The motivation for the system is that grid power is often unreliable, limited or even nonexistent remote\\/rural areas such as forward operating bases and schools and hospitals in developing countries. The challenge of this system is to provide a reliable, cost-effective power management system that is scalable and uses renewable energy sources.

Chi Cheung; K. Bengtson; M. Moser; A. Wu; B. Parrilla; C. Mastrangelo

2009-01-01

416

Development and Design of a Dynamic Multimedia Item Generation Mechanism  

ERIC Educational Resources Information Center

This research applies multimedia technology to design a dynamic item generation method that can adaptively adjust the difficulty level of items according to the level of the testee. The method is based on interactive testing software developed by Flash Actionscript, and provides a testing solution for users by automatically distributing items of…

Weng, Ting-Sheng

2012-01-01

417

Development and Design of a Dynamic Multimedia Item Generation Mechanism  

ERIC Educational Resources Information Center

|This research applies multimedia technology to design a dynamic item generation method that can adaptively adjust the difficulty level of items according to the level of the testee. The method is based on interactive testing software developed by Flash Actionscript, and provides a testing solution for users by automatically distributing items of…

Weng, Ting-Sheng

2012-01-01

418

Improving international assistance for renewable electricity generation in developing countries  

Microsoft Academic Search

Shifting electricity generation away from dependence on fossil fuels appears to be a necessary component of any global strategy for stabilizing atmospheric COâ concentrations. While achieving such a shift is important among all countries, several developing countries with high rates of economic growth are now heavily dependent on fossil fuels (particularly coal) for power production. Renewable electric technologies (from solar,

Kozloff

1995-01-01

419

Development of LMFBR Steam-Generator Leak-Protection Systems.  

National Technical Information Service (NTIS)

Leak protection for Liquid Metal Fast Breeder Reactor steam generators is an important economic factor in the shutdown, repair and restart of a plant. Development of leak protection systems in the US has concentrated on four areas: (1) chemical (H sub 2 a...

P. M. Magee E. E. Gerrels D. A. Greene J. McKee

1977-01-01

420

Some aspects of materials development for sodium heated steam generators  

Microsoft Academic Search

A development program was undertaken to support the materials selection for steam generator piping and IHX which are to be used in Liquid Metal Fast Breeder Reactors (LMFBR). Four major topics were reviewed, describing the results obtained as well as the direction of future tests. These topics are: carbon transport in sodium, effect of carbon loss\\/gain upon materials in the

P. Roy; C. N. Spalaris

1980-01-01

421

Some Aspects of Materials Development for Sodium Heated Steam Generators.  

National Technical Information Service (NTIS)

A development program was undertaken to support the materials selection for steam generator piping and IHX which are to be used in Liquid Metal Fast Breeder Reactors (LMFBR). Four major topics were reviewed, describing the results obtained as well as the ...

P. Roy C. N. Spalaris

1980-01-01

422

Synthesis and properties of sodium cobalt oxide thermoelectric materials  

Microsoft Academic Search

Since the unexpected good thermoelectric (TE) properties of the transition-metal oxide NaCo2O4 was reported by Terasaki in 1997, extensive research has been conducted on this promising TE material. In this study, the plate-like NaCo2O4 crystals were synthesized by the typical NaCl flux method. Also, via the novel low temperature flux method we developed, the Na-deficient NaxCo2O4 platelets with size up

Xiaofeng Tang

2005-01-01

423

QUANTUM WELL THERMOELECTRICS FOR CONVERTING WASTE HEAT TO ELECTRICITY  

SciTech Connect

New thermoelectric materials using Quantum Well (QW) technology are expected to increase the energy conversion efficiency to more than 25% from the present 5%, which will allow for the low cost conversion of waste heat into electricity. Hi-Z Technology, Inc. has been developing QW technology over the past six years. It will use Caterpillar, Inc., a leader in the manufacture of large scale industrial equipment, for verification and life testing of the QW films and modules. Other members of the team are Pacific Northwest National Laboratory, who will sputter large area QW films. The Scope of Work is to develop QW materials from their present proof-of-principle technology status to a pre-production level over a proposed three year period. This work will entail fabricating the QW films through a sputtering process of 50 {micro}m thick multi layered films and depositing them on 12 inch diameter, 5 {micro}m thick Si substrates. The goal in this project is to produce a basic 10-20 watt module that can be used to build up any size generator such as: a 5-10 kW Auxiliary Power Unit (APU), a multi kW Waste Heat Recovery Generator (WHRG) for a class 8 truck or as small as a 10-20 watt unit that would fit on a daily used wood fired stove and allow some of the estimated 2-3 billion people on earth, who have no electricity, to recharge batteries (such as a cell phone) or directly power radios, TVs, computers and other low powered devices.

Saeid Ghamaty; Sal Marchetti

2005-03-03

424

QUANTUM WELL THERMOELECTRICS FOR CONVERTING WASTE HEAT TO ELECTRICITY  

SciTech Connect

New thermoelectric materials using Quantum Well (QW) technology are expected to increase the energy conversion efficiency to more than 25% from the present 5%, which will allow for the low cost conversion of waste heat into electricity. Hi-Z Technology, Inc. has been developing QW technology over the past six years. It will use Caterpillar, Inc., a leader in the manufacture of large scale industrial equipment, for verification and life testing of the QW films and modules. Other members of the team are Pacific Northwest National Laboratory, who will sputter large area QW films. The Scope of Work is to develop QW materials from their present proof-of-principle technology status to a pre-production level over a proposed three year period. This work will entail fabricating the QW films through a sputtering process of 50 {micro}m thick multi layered films and depositing them on 12 inch diameter, 5 {micro}m thick Si substrates. The goal in this project is to produce a basic 10-20 watt module that can be used to build up any size generator such as: a 5-10 kW Auxiliary Power Unit (APU), a multi kW Waste Heat Recovery Generator (WHRG) for a class 8 truck or as small as a 10-20 watt unit that would fit on a daily used wood fired stove and allow some of the estimated 2-3 billion people on earth, who have no electricity, to recharge batteries (such as a cell phone) or directly power radios, TVs, computers and other low powered devices.

Saeid Ghamaty; Sal Marchetti

2004-05-10

425

QUANTUM WELL THERMOELECTRICS FOR CONVERTING WASTE HEAT TO ELECTRICITY  

SciTech Connect

New thermoelectric materials using Quantum Well (QW) technology are expected to increase the energy conversion efficiency to more than 25% from the present 5%, which will allow for the low cost conversion of waste heat into electricity. Hi-Z Technology, Inc. has been developing QW technology over the past six years. It will use Caterpillar, Inc., a leader in the manufacture of large scale industrial equipment, for verification and life testing of the QW films and modules. Other members of the team are Pacific Northwest National Laboratory, who will sputter large area QW films. The Scope of Work is to develop QW materials from their present proof-of-principle technology status to a pre-production level over a proposed three year period. This work will entail fabricating the QW films through a sputtering process of 50 {micro}m thick multi layered films and depositing them on 12 inch diameter, 5 {micro}m thick Si substrates. The goal in this project is to produce a basic 10-20 watt module that can be used to build up any size generator such as: a 5-10 kW Auxiliary Power Unit (APU), a multi kW Waste Heat Recovery Generator (WHRG) for a class 8 truck or as small as a 10-20 watt unit that would fit on a daily used wood fired stove and allow some of the estimated 2-3 billion people on earth, who have no electricity, to recharge batteries (such as a cell phone) or directly power radios, TVs, computers and other low powered devices.

Saeid Ghamaty; Sal Marchetti

2004-07-30

426

Thermoelectric effects in nanoscale junctions.  

PubMed

Despite its intrinsic nonequilibrium origin, thermoelectricity in nanoscale systems is usually described within a static scattering approach which disregards the dynamical interaction with the thermal baths that maintain energy flow. Using the theory of open quantum systems, we show instead that unexpected properties, such as a resonant structure and large sign sensitivity, emerge if the nonequilibrium nature of this problem is considered. Our approach also allows us to define and study a local temperature, which shows hot spots and oscillations along the system according to the coupling of the latter to the electrodes. This demonstrates that Fourier's lawa paradigm of statistical mechanicsis generally violated in nanoscale junctions. PMID:19072125

Dubi, Yonatan; Di Ventra, Massimiliano

2009-01-01

427

Thermoelectric power in carbon nanotubes  

SciTech Connect

The theoretical results for the temperature dependence of the thermoelectric power of graphite and semimetal carbon nanotubes are reported. In the calculations, the cylindrical superatomic range structure of nanotubes is taken into account. The Boltzmann equation and the {pi}-electron model of semimetal carbon nanotubes are used. The basic parameters of the calculation are the concentration of electrons, the Fermi energy, and the energy of the local level associated with the cylindrical structure of carbon nanotubes. The theoretical results are compared with the available experimental data.

Mavrinskiy, A. V., E-mail: mavrinsky@gmail.com; Baitinger, E. M. [Chelyabinsk State Pedagogical University (Russian Federation)

2009-04-15

428

Development of a new generation of optical slope measuring profiler  

SciTech Connect

We overview the results of a broad US collaboration, including all DOE synchrotron labs (ALS, APS, BNL, NSLS-II, LLNL, LCLS), major industrial vendors of x-ray optics (InSync, Inc., SSG Precision Optronics-Tinsley, Inc., Optimax Systems, Inc.), and with active participation of HBZ-BESSY-II optics group, on development of a new generation slope measuring profiler -- the optical slope measuring system (OSMS). The desired surface slope measurement accuracy of the instrument is<50 nrad (absolute) that is adequate to the current and foreseeable future needs for metrology of x-ray optics for the next generation of light sources.

Yashchuk, Valeriy V.; Takacs, Peter Z.; McKinney, Wayne R.; Assoufid, Lahsen

2010-07-09

429

Second-generation heliostat development. Volume 1: Detailed design report  

NASA Astrophysics Data System (ADS)

The results of a second generation heliostat development program are presented. This includes: (1) a presentation of the detailed design of the second generation heliostat with the supportive analyses and component test data; (2) preliminary design of the manufacturing plant; and (3) the projected cost to manufacture, transport, install, and maintain 50,000 heliostats per year installed in 50 MWe fields. The heliostat is the mass production design. Due to the absence of mass production tooling, the prototype heliostats have some differences from the mass production heliostats. These differences are described at the component level.

Oldham, L. P.

1980-09-01

430

Noncontacting thermoelectric detection of material imperfections in metals  

SciTech Connect

This project was aimed at developing a new noncontacting thermoelectric method for nondestructive detection of material imperfections in metals. The method is based on magnetic sensing of local thermoelectric currents around imperfections when a temperature gradient is established throughout a conducting specimen by external heating and cooling. The surrounding intact material serves as the reference electrode therefore the detection sensitivity could be very high if a sufficiently sensitive magnetometer is used in the measurements. This self-referencing, noncontacting, nondestructive inspection technique offers the following distinct advantages over conventional methods: high sensitivity to subtle variations in material properties, unique insensitivity to the size, shape, and other geometrical features of the specimen, noncontacting nature with a substantial stand-off distance, and the ability to probe relatively deep into the material. The potential applications of this method cover a very wide range from detection metallic inclusions and segregations, inhomogeneities, and tight cracks to characterization of hardening, embrittlement, fatigue, texture, and residual stresses.

Peter B. Nagy; Adnan H. Nayfeh; Waseem I. Faidi; Hector Carreon; Balachander Lakshminaraya; Feng Yu; Bassam Abu-Nabah

2005-06-17

431

Study of thermoelectric technology for automobile air conditioning  

SciTech Connect

An analytical study was conducted to determine the feasibility of employing thermoelectric (TE) cooling technology in automobile air conditioners. The study addressed two key issues -- power requirements and availability of thermoelectric materials. In this paper, a mathematical model was developed to predict the performance of TE air conditioners and to analyze power consumption. Results show that the power required to deliver a cooling capacity of 4 kW (13,80 Btu/h) in a 38{degree}C (100{degree}F) environment will be 9.5 kW electric. Current TE modules suitable for air conditioning are made of bismuth telluride. The element tellurium is expected to be in short supply if TE cooling is widely implemented for auto air conditioning; some options available in this regard were studied and presented in this paper.

Mathiprakasam, B.; Heenan, P. (Midwest Research Inst., Kansas City, MO (United States)); Mei, V.C.; Chen, F.C. (Oak Ridge National Lab., TN (United States))

1991-01-01

432

Berry-phase effect in anomalous thermoelectric transport.  

PubMed

We develop a theory of the Berry-phase effect in anomalous transport in ferromagnets driven by statistical forces such as the gradient of temperature or chemical potential. Here a charge Hall current arises from the Berry-phase correction to the orbital magnetization rather than from the anomalous velocity, which does not exist in the absence of a mechanical force. A finite-temperature formula for the orbital magnetization is derived, which enables us to provide an explicit expression for the off-diagonal thermoelectric conductivity, to establish the Mott relation between the anomalous Nernst and Hall effects, and to reaffirm the Onsager relations between reciprocal thermoelectric conductivities. A first-principles evaluation of our expression is carried out for the material CuCr(2)Se(4-x)Br(x), obtaining quantitative agreement with a recent experiment. PMID:16907470

Xiao, Di; Yao, Yugui; Fang, Zhong; Niu, Qian

2006-07-14

433

Berry-Phase Effect in Anomalous Thermoelectric Transport  

NASA Astrophysics Data System (ADS)

We develop a theory of the Berry-phase effect in anomalous transport in ferromagnets driven by statistical forces such as the gradient of temperature or chemical potential. Here a charge Hall current arises from the Berry-phase correction to the orbital magnetization rather than from the anomalous velocity, which does not exist in the absence of a mechanical force. A finite-temperature formula for the orbital magnetization is derived, which enables us to provide an explicit expression for the off-diagonal thermoelectric conductivity, to establish the Mott relation between the anomalous Nernst and Hall effects, and to reaffirm the Onsager relations between reciprocal thermoelectric conductivities. A first-principles evaluation of our expression is carried out for the material CuCr2Se4-xBrx, obtaining quantitative agreement with a recent experiment.

Xiao, Di; Yao, Yugui; Fang, Zhong; Niu, Qian

2006-07-01

434

An apparatus for concurrent measurement of thermoelectric material parameters  

NASA Astrophysics Data System (ADS)

We describe an apparatus which concurrently and independently measures the parameters determining thermoelectric material conversion efficiency: the Seebeck coefficient, thermal conductivity, and electrical resistivity. The apparatus is designed to characterize thermoelectric materials which are technologically relevant for waste heat energy conversion, and may operate from room temperature to 400 °C. It is configured so the heat flux is axially confined along two boron nitride rods of known thermal conductance. The Seebeck coefficient and thermal conductivity are obtained in steady-state using a differential technique, while the electrical resistivity is obtained using a four-point lock-in amplification method. Measurements on the newly developed NIST Seebeck standard reference material are presented in the temperature range from 50 °C to 250 °C.

Kallaher, R. L.; Latham, C. A.; Sharifi, F.

2013-01-01

435

Copper-based diamond-like ternary semiconductors for thermoelectric applications  

NASA Astrophysics Data System (ADS)

Heightened global concern over greenhouse gas emissions has led to an increased demand for clean energy conversion technologies. Thermoelectric materials convert directly between thermal and electrical energy and can increase the efficiency of existing processes via waste heat recovery and solid-state climate control applications. The conversion efficiency of available thermoelectric materials and the devices comprised of them is unfortunately quite low, and thus new materials must be developed in order for thermoelectrics to keep pace with competing technologies. One approach to increasing the conversion efficiency of a given material is to decrease its lattice thermal conductivity, which has traditionally been accomplished by introducing phonon scattering centers into the material. These scattering centers also tend to degrade electronic transport in the material, thereby minimizing the overall effect on the thermoelectric performance. The purpose of this work is to develop materials with inherently low lattice thermal conductivity such that no extrinsic modifications are required. A novel approach in which complex ternary semiconductors are derived from well-known binary or elemental semiconductors is employed to identify candidate materials. Ternary diamond-like compounds, namely Cu2SnSe 3 and Cu3SbSe4, are synthesized, characterized, and optimized for thermoelectric applications. It is found that sample-to-sample variations in hole concentration limits the plausibility of Cu2SnSe3 as a thermoelectric material. Cu3SbSe 4 is found to be a promising material that can achieve thermoelectric performance comparable to state-of-the-art materials when optimized. This work uncovers anomalous thermal conductivity in several Cu-Sb-Se ternary compounds, which is used to develop a set of guidelines relating crystal structure to inherently low lattice thermal conductivity.

Skoug, Eric John

436

A comparison of thermoelectric phenomena in diverse alloy systems  

SciTech Connect

The study of thermoelectric phenomena in solids provides a wealth of opportunity for exploration of the complex interrelationships between structure, processing, and properties of materials. As thermoelectricity implies some type of coupled thermal and electrical behavior, it is expected that a basic understanding of transport behavior in materials is the goal of such a study. However, transport properties such as electrical resistivity and thermal diffusivity cannot be fully understood and interpreted without first developing an understanding of the material's preparation and its underlying structure. It is the objective of this dissertation to critically examine a number of diverse systems in order to develop a broad perspective on how structure-processing-property relationships differ from system to system, and to discover the common parameters upon which any good thermoelectric material is based. The alloy systems examined in this work include silicon-germanium, zinc oxide, complex intermetallic compounds such as the half-Heusler MNiSn, where M = Ti, Zr, or Hf, and rare earth chalcogenides.

Cook, Bruce

1999-01-01

437

Diaphragm Pressure Wave Generator Developments at Industrial Research Ltd  

NASA Astrophysics Data System (ADS)

Industrial Research Ltd (IRL) have been developing a unique diaphragm based pressure wave generator technology for pulse tube and Stirling cryocoolers. Our system uses a metal diaphragm to separate the clean cryocooler gas circuit from a conventionally lubricated mechanical driver, thus producing a clean pressure wave with a long life drive that does not require the precision manufacture and associated costs of large linear motors. The first successful diaphragm pressure wave generator produced 3.2 kW of acoustic power at an electro-acoustic efficiency of 72% with a swept volume of 200 ml and a prototype has now accumulated over 2500 hours running. This paper describes recent developments in the technology. To explore scaling, a small diaphragm pressure wave generator with a swept volume of 20 ml has been constructed and has delivered 454 W of acoustic power at an electro-acoustic efficiency of 60%. Improvements have been made to the hydraulic force amplifier mechanism for driving the diaphragms resulting in a cheaper and lighter mechanism than the mechanical linkage originally used. To meet a customer's specific requirements, the 200 ml pressure wave generator's stroke was extended to achieve 240 ml of swept volume thereby increasing its acoustic power delivery to 4.1 kW without compromising efficiency.

Caughley, A. J.; Emery, N.; Glasson, N. D.

2010-04-01

438

Thermoelectric conversion for space nuclear power  

SciTech Connect

A lightweight, high performance nuclear reactor power system can offer significant advantages for many space missions. Conceptual design has been completed for the SP-100, a system which utilizes many thermoelectric converters and is capable of delivering 100 kilowatts of electrical power. A reference design, using thermoelectric materials with an average figure of merit of 1.0 X 10/sup -3/K/sup -1/ and a reactor heat pipe temperature of 1500 K, is presented which has a mass of 2280 kg not including contingency. The sensitivity of system mass to changes in the configuration and thermoelectric material properties are presented.

Ewell, R.; Stapfer, G.

1982-08-01

439

Advanced heat source development for static and dynamic radioisotope space power systems  

Microsoft Academic Search

An advanced radioisotope heat source development for spacecraft power ; systems using thermoelectric generators or Brayton, Rankine, or Stirling power ; cycles is described. In the past, the majority of heat sources developed and ; launched have been comprised of one or two capsules containing the total fuel ; inventory in a single reentry heat shield. The new technology in

F. A. Schumann; W. E. Osmeyer

1975-01-01

440

Development of second-generation PFB combustion plants  

SciTech Connect

Research is being conducted under United States Department of Energy (USDOE) Contract DE-AC21-86MC21023 to develop a new type of coal-fueled plant for electric power generation. This new type of plant--called an Advanced or Second-generation Pressurized Fluidized Bed Combustion (APFBC) plant--offers the promise of efficiencies greater than 45 percent (HHV), with both emissions and a cost of electricity that are significantly lower than conventional pulverized-coal-fired plants with scrubbers. This paper summarizes the pilot-plant R&D work being conducted to develop this new type of plant and discusses a proposed design that should reduce demonstration-plant risks and costs.

Robertson, A.; Domeracki, W.; Horazak, D. [and others

1995-12-31

441

Progress in second-generation HTS wire development and manufacturing  

Microsoft Academic Search

2007 has marked yet another year of continued rapid progress in developing and manufacturing high-performance, long-length second-generation (2G) HTS wires at high speeds. Using ion beam assisted deposition (IBAD) MgO and associated buffer sputtering processes, SuperPower has now exceeded piece lengths of 1000m of fully buffered tape reproducibly with excellent in-plane texture of 6–7 degrees and uniformity of about 2%.

V. Selvamanickam; Y. Chen; X. Xiong; Y. Xie; X. Zhang; A. Rar; M. Martchevskii; R. Schmidt; K. Lenseth; J. Herrin

2008-01-01

442

Development of a technological base for a solar steam generator  

SciTech Connect

The purpose of this program is to develop a technological base from which cost effective solar industrial steam generation systems could be designed. A specific goal of the program were to design and then build a heat pipe/GE TC-300 solar collector. Further objectives, which were added later in the program, included design and testing of an unfired boiler and reconstruction of the system using U-tubes in lieu of heat pipes in the collectors.

Thomas, W.E. Jr.

1981-01-01

443

The next generation high data rate VCSEL development at SEDU  

NASA Astrophysics Data System (ADS)

In May of 2012, Emcore's VCSEL FAB and VCSEL based transceiver business joined Sumitomo Electric Device Innovations USA (SEDU). After this change of ownership, our high speed VCSEL development effort continues. In this paper, we will report the progress we made in the past year in our 25Gbps to 28Gbps VCSEL. This next generation device is targeted for EDR, 32GFC as well as other optical interconnect applications.

Xie, Chuan; Li, Neinyi; Huang, Shenghong; Liu, Chiyu; Wang, Li; Jackson, Kenneth P.

2013-03-01

444

Magnetic and Thermoelectric Properties of Boron-Rich Solids  

NASA Astrophysics Data System (ADS)

Boron forms various compounds with metal atoms occupying voids in the boron framework. As a synthesis method it has been found that the addition of small amounts of third elements like carbon, nitrogen, and silicon can result in the formation of novel and varied rare earth boron cluster structures. A wide variation of 1D, 2D, and 3D magnetic behavior with unexpectedly strong magnetic interactions has been discovered in rare earth boron icosahedra compounds which are magnetically dilute, f-electron insulators. As an intriguing phenomenon, the B12 icosahedra cluster, which is a building block of the structure, has been indicated to function as a novel mediator of magnetic interaction. These phenomena are borides. Attractive high temperature thermoelectric properties are also emerging in borides. Attractive high temperature thermoelectric properties are also emerging in this group of compounds, which is striking due to the great potential of utilizing waste heat. Recent developments on the long awaited n-type counterpart to boron carbide, the homologous series of RE-B-C(N) compounds, REB17CN, REB22C2N, and REB28.5C4, will be presented together with those of p-type REB44Si2. General new ways to improve the thermoelectric properties are also discussed. For example, seeding with highly electrically co