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Sample records for thermoelectric generator development

  1. Developing instrumentation to characterize thermoelectric generator modules

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  2. Developing instrumentation to characterize thermoelectric generator modules.

    PubMed

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

    2015-03-01

    Based on the law of physics, known as "Seebeck effect," a thermoelectric generator (TEG) produces electricity when the temperature differential is applied across the TEG. This article reports a precision method in characterizing TEG modules. A precision instrument is constructed to study thermoelectric conversion in terms of output power and efficiency of TEG modules. The maximum allowable TEG module size is 150 mm, and the preferred size is from 30 mm to 60 mm. During measurements, the highest hot side temperature is 500 °C and the cold side temperature can be adjusted from room temperature to 100 °C. A mechanical structure is developed to control the pressure and parallelism of the clamping force of the TEG on both its hot and cold sides. A heat flux measurement module is installed at its cold side, and the heat flux through TEGs can be measured in position. Finally, the energy conversion efficiency of TEGs is calculated from experimental data of both an output power and a heat flux. PMID:25832254

  3. Design and development of thermoelectric generator

    SciTech Connect

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

    2014-04-24

    In this paper we discuss the fabrication, working and characteristics of a thermoelectric generator made up of p and n type semiconductor materials. The device consists of Fe{sub 0.2}Co{sub 3.8}Sb{sub 11.5}Te{sub 0.5} (zT = 1.04 at 818 K) as the n-type and Zn4Sb3 (zT=0.8 at 550 K) as the p-type material synthesized by vacuum hot press method. Carbon paste has been used to join the semiconductor legs to metal (Molybdenum) electrodes to reduce the contact resistance. The multi-couple (4 legs) generator results a maximum output power of 1.083 mW at a temperature difference of 240 K between the hot and cold sides. In this investigation, an I-V characteristic, maximum output power of the thermoelectric module is presented. The efficiency of thermoelectric module is obtained as η = 0.273 %.

  4. Thermoelectric Generator

    NASA Technical Reports Server (NTRS)

    Cole, T.

    1985-01-01

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

  5. Thermoelectric Materials Development for Low Temperature Geothermal Power Generation

    DOE Data Explorer

    Tim Hansen

    2016-01-29

    Data includes characterization results for novel thermoelectric materials developed specifically for power generation from low temperature geothermal brines. Materials characterization data includes material density, thickness, resistance, Seebeck coefficient. This research was carried out by Novus Energy Partners in Cooperation with Southern Research Institute for a Department of Energy Sponsored Project.

  6. Thermoelectric generator

    DOEpatents

    Pryslak, N.E.

    1974-02-26

    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)

  7. Development of Next Generation Segmented Thermoelectric Radioisotope Power Systems

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

    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.

  8. Radioisotope thermoelectric generator transportation system subsystem 143 software development plan

    NASA Astrophysics Data System (ADS)

    King, D. A.

    1994-11-01

    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.

  9. Radioisotope thermoelectric generator transportation system subsystem 143 software development plan

    SciTech Connect

    King, D.A.

    1994-11-10

    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.

  10. Development and optimization of a stove-powered thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Mastbergen, Dan

    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.

  11. Thermally cascaded thermoelectric generator

    NASA Technical Reports Server (NTRS)

    Flaherty, R.

    1970-01-01

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

  12. Thermoelectric generator

    SciTech Connect

    Shakun, W.; Bearden, J.H.; Henderson, D.R.

    1988-03-29

    A thermoelectric generator unit is described comprising: a hot side heat exchanger including a plate having extruded retention posts projecting from one surface of the plate, and fins adapted for contact with a heating source. The fins are positioned between two of the retention posts. Retention rods are inserted between the retention posts and the base of the fins to retain the fin in thermal contact with the plate surface upon insertion of the retention rod between the engaging surface of the post and the corresponding fin. Thermoelectric semi-conductor modules are in thermal contact with the opposite side of the hot side heat exchanger plate from the contact with the fins. The modules are arranged in a grid pattern so that heat flow is directed into each of the modules from the hot side heat exchanger. The modules are connected electrically so as to combine their electrical output; and a cold side heat exchanger is in thermal contact with the modules acting as a heat sink on the opposite side of the module from the hot side heat exchanger plate so as to produce a thermal gradient across the modules.

  13. Advanced Thermoelectric Materials for Radioisotope Thermoelectric Generators

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  14. Component for thermoelectric generator

    DOEpatents

    Purdy, David L.

    1977-01-01

    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.

  15. Hybrid thermoelectric piezoelectric generator

    NASA Astrophysics Data System (ADS)

    Montgomery, D. S.; Hewitt, C. A.; Carroll, D. L.

    2016-06-01

    This work presents an integration of flexible thermoelectric and piezoelectric materials into a single device structure. This device architecture overcomes several prohibitive issues facing the combination of traditional thermoelectric and piezoelectric generators, while optimizing performance of the combined power output. The structure design uses a carbon nanotube/polymer thin film as a flexible thermoelectric generator that doubles as an electrode on a piezoelectric generator made of poly(vinylidene fluoride). An example 2 × 2 array of devices is shown to generate 89% of the maximum thermoelectric power, and provide 5.3 times more piezoelectric voltage when compared with a traditional device.

  16. The design, development, fabrication and testing of a 100 watt skutterudite thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Lyle, Matthew

    Thermoelectric technology is a method of renewable, alternative energy that utilizes the Seebeck effect to convert some of the thermal energy in a temperature gradient to electricity. The optimal temperature range for skutterudite thermoelectric devices is around 650°C, making them ideal for high temperature applications. At this temperature range, the skutterudite thermoelectrics have a device-level conversion efficiency of about 9% [1]. As these devices are still in the development stage, testing that simulates real-world conditions is necessary to assess the feasibility of implementing skutterudite thermoelectric technology with current processes. A standardized procedure to test the skutterudite thermoelectric devices has been established to reduce variability in device fabrication and generator assembly. This procedure includes a measurement and tracking system to aid in establishing relationships between component properties and thermoelectric performance. In addition, a technology has been developed to electrically bypass any failed devices to preserve overall power generation. Results indicate that additional efforts are needed to address the high level of thermal stresses the devices experience during operation. Several methods to reduce thermal stresses and investigate potential stressors are proposed. In addition, the successful performance of the electrical bypass technology suggests that it is indeed a viable method of bypassing individual devices for experimental tests. Additional testing and improvements can be made as necessary to implement this technology in the envisioned 1 kW skutterudite thermoelectric generator.

  17. Modular Isotopic Thermoelectric Generator

    SciTech Connect

    Schock, Alfred

    1981-04-03

    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.

  18. Solar thermoelectric generator

    DOEpatents

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

    2016-05-03

    Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. A novel detailed balance model for STEGs is provided and applied to both state-of-the-art and idealized materials. STEGs can produce electricity by using sunlight to heat one side of a thermoelectric generator. While concentrated sunlight can be used to achieve extremely high temperatures (and thus improved generator efficiency), the solar absorber also emits a significant amount of black body radiation. This emitted light is the dominant loss mechanism in these generators. In this invention, we propose a solution to this problem that eliminates virtually all of the emitted black body radiation. This enables solar thermoelectric generators to operate at higher efficiency and achieve said efficient with lower levels of optical concentration. The solution is suitable for both single and dual axis solar thermoelectric generators.

  19. Solar thermoelectric generators

    NASA Technical Reports Server (NTRS)

    1977-01-01

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

  20. Development of a High Efficiency Thermoelectric Unicouple for Power Generation Applications

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  1. Superconducting thermoelectric generator

    DOEpatents

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

    1994-01-01

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

  2. Modular isotopic thermoelectric generator

    SciTech Connect

    Schock, A.

    1981-01-01

    Advanced RTG concepts utilizing improved thermoelectric materials and converter concepts are under study at Fairchild for DOE. The design described is based on DOE's newly developed radioisotope heat source, and on an improved silicon-germanium material and a multicouple converter module under development. 14 refs.

  3. Development of advanced thermoelectric materials

    NASA Technical Reports Server (NTRS)

    1984-01-01

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

  4. Superconducting thermoelectric generator

    SciTech Connect

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

    1998-05-05

    An apparatus and method for producing electricity from heat is disclosed. The present invention is a thermoelectric generator that uses materials with substantially no electrical resistance, often called superconductors, to efficiently convert heat into electrical energy without resistive losses. Preferably, an array of superconducting elements is encased within a second material with a high thermal conductivity. The second material is preferably a semiconductor. Alternatively, the superconducting material can be doped on a base semiconducting material, or the superconducting material and the semiconducting material can exist as alternating, interleaved layers of waferlike materials. A temperature gradient imposed across the boundary of the two materials establishes an electrical potential related to the magnitude of the temperature gradient. The superconducting material carries the resulting electrical current at zero resistivity, thereby eliminating resistive losses. The elimination of resistive losses significantly increases the conversion efficiency of the thermoelectric device. 4 figs.

  5. Superconducting thermoelectric generator

    SciTech Connect

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

    1996-01-01

    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.

  6. Superconducting thermoelectric generator

    DOEpatents

    Metzger, John D.; El-Genk, Mohamed S.

    1998-01-01

    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.

  7. Modular Isotopic Thermoelectric Generator

    SciTech Connect

    Schock, Alfred

    1981-01-01

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

  8. Towards Improved Thermoelectric Generator Materials

    NASA Astrophysics Data System (ADS)

    Julian Goldsmid, H.

    2016-07-01

    Over recent years, new thermoelectric materials have been developed with values for the dimensionless figure of merit, zT, substantially greater than unity. This has opened up the possibility of many new applications, particularly those involving the utilisation of waste heat. However, further improvements are necessary if thermoelectric generation is to have a significant impact on the world's energy problems. It is well known that zT for a single energy band can be related to the Fermi energy and a parameter (μ/λ L) (m*/m)3/2, where μ is the carrier mobility, m*/m is the ratio of the carrier effective mass to the mass of a free electron and λ L is the lattice thermal conductivity. However, even when this parameter tends towards infinity, zT does not become much greater than 1 unless the Fermi level lies within the energy gap, far from the appropriate band edge. Thus, the magnitude of the energy gap is becoming of increasing importance. The two-fold requirements of a high value of (μ/λ L) (m*/m)3/2 and a sufficiently large energy gap are discussed. It is also shown that the likelihood of the required conditions being met at elevated temperatures can be predicted from low-temperature observations. It is, of course, much more difficult to make accurate determinations of the thermoelectric properties at higher temperatures.

  9. Thermoelectric generator for motor vehicle

    DOEpatents

    Bass, John C.

    1997-04-29

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

  10. Thermoelectric power generation system optimization studies

    NASA Astrophysics Data System (ADS)

    Karri, Madhav A.

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

  11. Thermoelectric Energy Conversion: Future Directions and Technology Development Needs

    NASA Technical Reports Server (NTRS)

    Fleurial, Jean-Pierre

    2007-01-01

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

  12. Research and Development for Thermoelectric Generation Technology Using Waste Heat from Steelmaking Process

    NASA Astrophysics Data System (ADS)

    Kuroki, Takashi; Murai, Ryota; Makino, Kazuya; Nagano, Kouji; Kajihara, Takeshi; Kaibe, Hiromasa; Hachiuma, Hirokuni; Matsuno, Hidetoshi

    2015-06-01

    In Japan, integrated steelworks have greatly lowered their energy use over the past few decades through investment in energy-efficient processes and facilities, maintaining the highest energy efficiency in the world. However, in view of energy security, the steelmaking industry is strongly required to develop new technologies for further energy saving. Waste heat recovery can be one of the key technologies to meet this requirement. To recover waste heat, particularly radiant heat from steel products which has not been used efficiently yet, thermoelectric generation (TEG) is one of the most effective technologies, being able to convert heat directly into electric power. JFE Steel Corporation (JFE) implemented a 10-kW-class grid-connected TEG system for JFE's continuous casting line with KELK Ltd. (KELK), and started verification tests to generate electric power using radiant heat from continuous casting slab at the end of fiscal year 2012. The TEG system has 56 TEG units, each containing 16 TEG modules. This paper describes the performance and durability of the TEG system, which has been investigated under various operating conditions at the continuous casting line.

  13. Design Calculations for Thermoelectric Generators

    NASA Technical Reports Server (NTRS)

    Zeldin, B.

    1983-01-01

    Nine simplified analytic models based on average properties accurately predict heat rates for silicon/germanium thermoelectric generators. Solutions from simplified models were compared with those obtained using sophisticated numerical analysis. Maximum errors in calculated heat rate range from about 4 percent to about 0.2 percent. Models also used to calculate power delivered to load and thermodynamic efficiency.

  14. Thermoelectric Development at Hi-Z Technology

    SciTech Connect

    Kushch, Aleksandr S.; Bass, John C.; Ghamaty, Saeid; Elsner, Norbert B.; Bergstrand, Richard A.; Furrow, David; Melvin, Mike

    2002-08-25

    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.

  15. Safety monitoring system for radioisotope thermoelectric generators

    NASA Technical Reports Server (NTRS)

    Zoltan, A.

    1973-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Stapfer, G.; Truscello, V. C.

    1977-01-01

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

  17. Thermoelectric cooling and power generation

    PubMed

    DiSalvo

    1999-07-30

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

  18. Design and optimization of compatible, segmented thermoelectric generators

    NASA Technical Reports Server (NTRS)

    Snyder, G. Jeffrey

    2003-01-01

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

  19. Designing, building, and testing a solar thermoelectric generation, STEG, for energy delivery to remote residential areas in developing regions

    NASA Astrophysics Data System (ADS)

    Moumouni, Yacouba

    New alternatives and inventive renewable energy techniques which encompass both generation and power management solutions are fundamental for meeting remote residential energy supply and demand today, especially if the grid is quasi-inexistent. Solar thermoelectric generators can be a cost-effective alternative to photovoltaics for a remote residential household power supply. A complete solar thermoelectric energy harvesting system is presented for energy delivery to remote residential areas in developing regions. To this end, the entire system was built, modeled, and then validated with LTspice simulator software via thermal-to-electrical analogy schemes. Valuable data in conjunction with two novel LTspice circuits were obtained, showing the achievability of analyzing transient heat transfer with the Spice simulator. Hence, the proposed study begins with a comprehensive method of extracting thermal parameters that appear in thermoelectric modules. A step-by-step procedure was developed and followed to succinctly extract parameters, such as the Seebeck coefficient, electrical conductivity, thermal resistance, and thermal conductivity needed to model the system. Data extracted from datasheet, material properties, and geometries were successfully utilized to compute the thermal capacities and resistances necessary to perform the analogy. In addition, temperature variations of the intrinsic internal parameters were accounted for in this process for accuracy purposes. The steps that it takes to simulate any thermo-electrical system with the LTspice simulator are thoroughly explained in this work. As a consequence, an improved Spice model for a thermoelectric generator is proposed. Experimental results were compiled in the form of a lookup table and then fed into the Spice simulator using the piecewise linear (PWL) command in order to validate the model. Experimental results show that a temperature differential of 13.43°C was achievable whereas the simulation indicates

  20. Thermoelectric materials development

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

    A systematic search for advanced thermoelectric materials was initiated at JPL several years ago to evaluate candidate materials which includes consideration of the following property attributes: (1) semiconducting properties; (2) large Seebeck coefficient; (3) high carrier mobility and high electrical conductivity; (4) low lattice thermal conductivity; and (5) chemical stability and low vapor pressure. Through this candidate screening process, JPL identified several families of materials as promising candidates for improved thermoelectric materials including the skutterudite family. As part of an ongoing effort to develop skutterudite materials with lower thermal conductivity values, several solid solutions and filled skutterudite materials were investigated under the effort sponsored by DOE. The efforts have primarily focused on: (1) study of existence and properties of solid solutions between the binary compounds CoSb3 and IrSb3, and RuSb2Te, and (2) CeFe(4-x)Sb12 based filled compositions. For the solid solutions, the lattice thermal conductivity reduction was expected to be reduced by the introduction of the Te and Ru atoms while in the case of CeFe(4-x)Ru(x)Sb12 based filled compositions. For the solid solutions, the lattice thermal conductivity reduction was expected to be reduced by the introduction of the Te and Ru atoms while in the case of CeFe(4-x)Ru(x)Sb12 filled compositions, the reduction would be caused by the rattling of Ce atoms located in the empty voids of the skutterudite structure and the substitution of Fe for Ru. The details of the sample preparation and characterization of their thermoelectric properties are reported in this report.

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

    NASA Astrophysics Data System (ADS)

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

    1992-01-01

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

  2. Thermal analysis of thermoelectric power generator; Including thermal stresses

    NASA Astrophysics Data System (ADS)

    Al-Merbati, Abdulrahman Salman

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

  3. Radioisotope thermoelectric generator reliability and safety

    SciTech Connect

    Campbell, R.; Klein, J.

    1989-01-01

    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.

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

    SciTech Connect

    2010-03-01

    Thermoelectric power plants use large volumes of water for condenser cooling and other plant operations. Traditionally, this water has been withdrawn from the cleanest water available in streams and rivers. However, as demand for electrical power increases it places increasing demands on freshwater resources resulting in conflicts with other off stream water users. In July 2002, NETL and the Governor of Pennsylvania called for the use of water from abandoned mines to replace our reliance on the diminishing and sometimes over allocated surface water resource. In previous studies the National Mine Land Reclamation Center (NMLRC) at West Virginia University has demonstrated that mine water has the potential to reduce the capital cost of acquiring cooling water while at the same time improving the efficiency of the cooling process due to the constant water temperatures associated with deep mine discharges. The objectives of this project were to develop and demonstrate a user-friendly computer based design aid for assessing the costs, technical and regulatory aspects and potential environmental benefits for using mine water for thermoelectric generation. The framework provides a systematic process for evaluating the hydrologic, chemical, engineering and environmental factors to be considered in using mine water as an alternative to traditional freshwater supply. A field investigation and case study was conducted for the proposed 300 MW Beech Hollow Power Plant located in Champion, Pennsylvania. The field study based on previous research conducted by NMLRC identified mine water sources sufficient to reliably supply the 2-3,000gpm water supply requirement of Beech Hollow. A water collection, transportation and treatment system was designed around this facility. Using this case study a computer based design aid applicable to large industrial water users was developed utilizing water collection and handling principals derived in the field investigation and during previous

  5. Thermoelectric power generation for hybrid-electric vehicle auxiliary power

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

    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.

  6. Compatibility of segmented thermoelectric generators

    NASA Technical Reports Server (NTRS)

    Snyder, J.; Ursell, T.

    2002-01-01

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

  7. Performance testing of thermoelectric generators at JPL

    NASA Technical Reports Server (NTRS)

    Rouklove, P.; Truscello, V.

    1974-01-01

    Results of life tests of thermoelectric generators ranging in output power from 800 microwatts to 170 watts. Emphasis is placed on the results obtained from tests of three advanced prototypes - a high-performance generator, a transit-type generator, and a ring converter. In addition, the results of life tests of a number of generators representing Nimbus, Pioneer, and Viking technology are presented.

  8. Heat Management in Thermoelectric Power Generators.

    PubMed

    Zebarjadi, M

    2016-01-01

    Thermoelectric power generators are used to convert heat into electricity. Like any other heat engine, the performance of a thermoelectric generator increases as the temperature difference on the sides increases. It is generally assumed that as more heat is forced through the thermoelectric legs, their performance increases. Therefore, insulations are typically used to minimize the heat losses and to confine the heat transport through the thermoelectric legs. In this paper we show that to some extend it is beneficial to purposely open heat loss channels in order to establish a larger temperature gradient and therefore to increase the overall efficiency and achieve larger electric power output. We define a modified Biot number (Bi) as an indicator of requirements for sidewall insulation. We show cooling from sidewalls increases the efficiency for Bi values less than one, and decreases the efficiency for Bi values larger than one. PMID:27033717

  9. Heat Management in Thermoelectric Power Generators

    NASA Astrophysics Data System (ADS)

    Zebarjadi, M.

    2016-04-01

    Thermoelectric power generators are used to convert heat into electricity. Like any other heat engine, the performance of a thermoelectric generator increases as the temperature difference on the sides increases. It is generally assumed that as more heat is forced through the thermoelectric legs, their performance increases. Therefore, insulations are typically used to minimize the heat losses and to confine the heat transport through the thermoelectric legs. In this paper we show that to some extend it is beneficial to purposely open heat loss channels in order to establish a larger temperature gradient and therefore to increase the overall efficiency and achieve larger electric power output. We define a modified Biot number (Bi) as an indicator of requirements for sidewall insulation. We show cooling from sidewalls increases the efficiency for Bi values less than one, and decreases the efficiency for Bi values larger than one.

  10. Computer modeling of thermoelectric generator performance

    NASA Technical Reports Server (NTRS)

    Chmielewski, A. B.; Shields, V.

    1982-01-01

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

  11. Heat Management in Thermoelectric Power Generators

    PubMed Central

    Zebarjadi, M.

    2016-01-01

    Thermoelectric power generators are used to convert heat into electricity. Like any other heat engine, the performance of a thermoelectric generator increases as the temperature difference on the sides increases. It is generally assumed that as more heat is forced through the thermoelectric legs, their performance increases. Therefore, insulations are typically used to minimize the heat losses and to confine the heat transport through the thermoelectric legs. In this paper we show that to some extend it is beneficial to purposely open heat loss channels in order to establish a larger temperature gradient and therefore to increase the overall efficiency and achieve larger electric power output. We define a modified Biot number (Bi) as an indicator of requirements for sidewall insulation. We show cooling from sidewalls increases the efficiency for Bi values less than one, and decreases the efficiency for Bi values larger than one. PMID:27033717

  12. Thermoelectric generator cooling system and method of control

    SciTech Connect

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

    2012-10-16

    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.

  13. Polymer Thermoelectric Generators: Device Considerations

    NASA Astrophysics Data System (ADS)

    Yee, Shannon

    2014-03-01

    Recent control of the transport properties in polymers has encouraged the development of polymer thermoelectric (TE) devices. Polymer TEs are thought to be less expensive and more scalable than their inorganic counterparts. The cost of the raw material is less and polymer TEs can leverage the large areal manufacturing technique established by the plastics industry. Additionally, while the overall ZT of polymer TEs appears attractive, individual polymer properties have a very different scale than their inorganic counterparts (i.e., the thermal conductivity and electrical conductivity are approximately one and two orders of magnitude smaller, respectively). Furthermore, the majority of TE measurements on polymers have been limited to thin-films where traditional TE materials are measured in bulk. So why should it be expected that polymer TE devices resemble traditional TE devices? Given the uniqueness of polymers, different device architectures are proposed that can leverage the unique strengths of polymer films. It will be shown that by logically considering device requirements, new polymer TE devices have non-linear features that are more attractive than linear inorganic TE devices. This leads to very different device optimizations that favor polymer TEs.

  14. Thermoelectric fabrics: toward power generating clothing.

    PubMed

    Du, Yong; Cai, Kefeng; Chen, Song; Wang, Hongxia; Shen, Shirley Z; Donelson, Richard; Lin, Tong

    2015-01-01

    Herein, we demonstrate that a flexible, air-permeable, thermoelectric (TE) power generator can be prepared by applying a TE polymer (e.g. poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)) coated commercial fabric and subsequently by linking the coated strips with a conductive connection (e.g. using fine metal wires). The poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) coated fabric shows very stable TE properties from 300 K to 390 K. The fabric device can generate a TE voltage output (V) of 4.3 mV at a temperature difference (ΔT) of 75.2 K. The potential for using fabric TE devices to harvest body temperature energy has been discussed. Fabric-based TE devices may be useful for the development of new power generating clothing and self-powered wearable electronics. PMID:25804132

  15. Thermoelectric Fabrics: Toward Power Generating Clothing

    NASA Astrophysics Data System (ADS)

    Du, Yong; Cai, Kefeng; Chen, Song; Wang, Hongxia; Shen, Shirley Z.; Donelson, Richard; Lin, Tong

    2015-03-01

    Herein, we demonstrate that a flexible, air-permeable, thermoelectric (TE) power generator can be prepared by applying a TE polymer (e.g. poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)) coated commercial fabric and subsequently by linking the coated strips with a conductive connection (e.g. using fine metal wires). The poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) coated fabric shows very stable TE properties from 300 K to 390 K. The fabric device can generate a TE voltage output (V) of 4.3 mV at a temperature difference (ΔT) of 75.2 K. The potential for using fabric TE devices to harvest body temperature energy has been discussed. Fabric-based TE devices may be useful for the development of new power generating clothing and self-powered wearable electronics.

  16. Thermoelectric Fabrics: Toward Power Generating Clothing

    PubMed Central

    Du, Yong; Cai, Kefeng; Chen, Song; Wang, Hongxia; Shen, Shirley Z.; Donelson, Richard; Lin, Tong

    2015-01-01

    Herein, we demonstrate that a flexible, air-permeable, thermoelectric (TE) power generator can be prepared by applying a TE polymer (e.g. poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)) coated commercial fabric and subsequently by linking the coated strips with a conductive connection (e.g. using fine metal wires). The poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) coated fabric shows very stable TE properties from 300 K to 390 K. The fabric device can generate a TE voltage output (V) of 4.3 mV at a temperature difference (ΔT) of 75.2 K. The potential for using fabric TE devices to harvest body temperature energy has been discussed. Fabric-based TE devices may be useful for the development of new power generating clothing and self-powered wearable electronics. PMID:25804132

  17. Thermoelectric power generator with intermediate loop

    SciTech Connect

    Bell, Lon E; Crane, Douglas Todd

    2013-05-21

    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.

  18. Thermoelectric power generator with intermediate loop

    DOEpatents

    Bel,; Lon E.; Crane, Douglas Todd

    2009-10-27

    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.

  19. Microfabricated thermoelectric power-generation devices

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  20. Method of operating a thermoelectric generator

    SciTech Connect

    Reynolds, Michael G; Cowgill, Joshua D

    2013-11-05

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

  1. Microfabricated thermoelectric power-generation devices

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    SciTech Connect

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

    1996-07-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure.

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

    SciTech Connect

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

    1996-11-01

    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.

  4. Thermoelectric generator having a resiliently mounted removable thermoelectric module

    DOEpatents

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

    1976-11-02

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

  5. Compatibility of Segments of Thermoelectric Generators

    NASA Technical Reports Server (NTRS)

    Snyder, G. Jeffrey; Ursell, Tristan

    2009-01-01

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

  6. The thermoelectric generator test program at JPL.

    NASA Technical Reports Server (NTRS)

    Stapfer, G.; Rouklove, P.

    1972-01-01

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

  7. Safe radioisotope thermoelectric generators and heat sources for space applications

    NASA Astrophysics Data System (ADS)

    O'Brien, R. C.; Ambrosi, R. M.; Bannister, N. P.; Howe, S. D.; Atkinson, H. V.

    2008-07-01

    Several isotopes are examined as alternatives to 238Pu that is traditionally used in radioisotope thermoelectric generators (RTGs) and heating units (RHUs). The radioisotopes discussed include 241Am, 208Po, 210Po, and 90Sr. The aim of this study is to facilitate the design of an RTG with a minimal radiation dose rate and mass including any required shielding. Applications of interest are primarily space and planetary exploration. In order to evaluate the properties of the alternative radioisotopes a Monte Carlo model was developed to examine the radiation protection aspect of the study. The thermodynamics of the power generation process is examined and possible materials for the housing and encapsulation of the radioisotopes are proposed. In this study we also present a historical review of radioisotope thermoelectric generators (RTGs) and the thermoelectric conversion mechanism in order to provide a direct comparison with the performance of our proposed alternative isotope systems.

  8. Thermoelectric unicouple used for power generation

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  9. Molybdenum oxide electrodes for thermoelectric generators

    DOEpatents

    Schmatz, Duane J.

    1989-01-01

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

  10. Titanium nitride electrodes for thermoelectric generators

    DOEpatents

    Novak, Robert F.; Schmatz, Duane J.; Hunt, Thomas K.

    1987-12-22

    The invention is directed to a composite article suitable for use in thermoelectric generators. The article comprises a thin film of titanium nitride as an electrode deposited onto solid electrolyte. The invention is also directed to the method of making same.

  11. Development of segmented thermoelectric multicouple converter technology

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  12. Novel Fabrication Process for Micro Thermoelectric Generators (μTEGs)

    NASA Astrophysics Data System (ADS)

    Pelz, U.; Jaklin, J.; Rostek, R.; Kröner, M.; Woias, P.

    2015-12-01

    A cost effective bottom-up process for the fabrication of micro thermoelectric generators (μTEGs) was developed. It is based on a novel fabrication method involving a selectively sacrificial photoresist for the sequential galvanostatic electrodeposition of thermoelectric materials. The use of an industrial pick and placer (P&P) for dispensing the second photoresist allows for accurate and flexible μTEG designs. The process makes use of Ordyl® as a negative dry film photoresist template and sequential lamination steps for shaping all thermoelectric legs and contacts. All structures of the μTEG are generated in one photoresist multi-layer - this represents the most significant advantage of the process. The process uses a minimum of clean room processing for the preparation of pre-structured substrates for electrodeposition and therefore provides a cost-effective, highly flexible fabrication platform for research and development.

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

    SciTech Connect

    Schock, A.

    1983-04-29

    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.

  14. Development of Thermoelectric Self-Powered Heating Equipment

    NASA Astrophysics Data System (ADS)

    Qiu, K.; Hayden, A. C. S.

    2011-05-01

    In this work, a self-powered residential heating system was developed using thermoelectric generation technology. A full-size prototype was designed, constructed, and tested, in which Bi2Te3-based thermoelectric modules were incorporated into a gas-fired heating boiler. Up to 161 W of electricity is generated by the thermoelectric modules. This is sufficient to power all the electrical components of the residential heating equipment including pump, fan, blower, valves, and control panel. In this way, the heating system can operate entirely on fuel combustion and does not need externally generated electricity. The performance of the thermoelectric devices has been investigated in the integrated heating system under various operating conditions. The energy system's advantages include simplicity, low noise, clean operation, and low maintenance. The thermoelectric self-powered heating system could provide the consumer with heating system reliability and a reduction in electric power consumption.

  15. Thermophotovoltaic and thermoelectric portable power generators

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  16. Xenon Filled Silicon Germanium Thermoelectric Generators

    NASA Technical Reports Server (NTRS)

    Dewinter, F.

    1972-01-01

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

  17. Fabrication Process for Micro Thermoelectric Generators ( μTEGs)

    NASA Astrophysics Data System (ADS)

    Pelz, U.; Jaklin, J.; Rostek, R.; Thoma, F.; Kröner, M.; Woias, P.

    2016-03-01

    An innovative micro thermoelectric generator ( μTEG) fabrication process has been developed. Two selectively dissolvable photoresists and galvanostatic electrodeposition are used to grow p- and n-type thermoelectric materials as well as the upper and lower contacts of the μTEGs onto a single substrate. Two particular features of the process are the usage of a multilamination technique to create structures for legs and contacts, as well as an industrial pick and placer (P&P), which allows dispensing of a second, selectively dissolvable, photoresist to protect certain areas during material deposition. This allows sequential electrochemical deposition of two different thermoelectric materials on a single substrate, without further costly and time-consuming process steps. The process therefore provides a highly flexible fabrication platform for research and development.

  18. Solar thermoelectric power generation for Mercury orbiter missions

    NASA Technical Reports Server (NTRS)

    Swerdling, M.; Raag, V.

    1979-01-01

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

  19. Performance evaluation of an automotive thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Dubitsky, Andrei O.

    Around 40% of the total fuel energy in typical internal combustion engines (ICEs) is rejected to the environment in the form of exhaust gas waste heat. Efficient recovery of this waste heat in automobiles can promise a fuel economy improvement of 5%. The thermal energy can be harvested through thermoelectric generators (TEGs) utilizing the Seebeck effect. In the present work, a versatile test bench has been designed and built in order to simulate conditions found on test vehicles. This allows experimental performance evaluation and model validation of automotive thermoelectric generators. An electrically heated exhaust gas circuit and a circulator based coolant loop enable integrated system testing of hot and cold side heat exchangers, thermoelectric modules (TEMs), and thermal interface materials at various scales. A transient thermal model of the coolant loop was created in order to design a system which can maintain constant coolant temperature under variable heat input. Additionally, as electrical heaters cannot match the transient response of an ICE, modelling was completed in order to design a relaxed exhaust flow and temperature history utilizing the system thermal lag. This profile reduced required heating power and gas flow rates by over 50%. The test bench was used to evaluate a DOE/GM initial prototype automotive TEG and validate analytical performance models. The maximum electrical power generation was found to be 54 W with a thermal conversion efficiency of 1.8%. It has been found that thermal interface management is critical for achieving maximum system performance, with novel designs being considered for further improvement.

  20. Milliwatt thermoelectric generator for space applications

    NASA Astrophysics Data System (ADS)

    Allen, Daniel T.; Bass, John C.; Elsner, Norbert B.; Ghamaty, Saeid; Morris, Charles C.

    2000-01-01

    A small thermoelectric generator is being developed for general use in space, and in particular for any of several proposed Mars atmospheric probes and surface landers that may be launched in the 2003 to 2006 time period. The design is based on using an existing 1 watt radioisotope heater unit as the generator heat source. That is the Light-Weight Radioisotope Heater Unit (RHU) which has already been used to provide heating alone on numerous spacecraft, including the 1997 Pathfinder/Sojourner Mars lander. Important technical issues that need to be addressed in the detailed design are the mechanical integrity of the overall power supply in consideration of the impact of landing on Mars and the subsequent performance of the thermal insulation around the heat source, which is critical to delivering the output power. The power supply is intended to meet a 20-year operational lifetime. Hi-Z is developing milliwatt modules that make use of micro fabrication techniques. For this generator modules are being fabricated that produce approximately 40 milliwatts at a T-hot of 250 °C and a T-cold of 25 °C. The module is composed of an 18×18 array of 0.38 mm (0.015'') square×22.9 mm(0.900'') long N and P elements. The modules use bismuth-telluride based alloys that are fine grain metallurgy prepared materials that can endure the demanding fabrication techniques. The paper describes the design status to date, and it presents the analytical approach, the testing program plan and a manufacturing schedule that is needed to meet the launch dates being considered. Electrical performance and life test data for the modules is also presented. .

  1. Thermoelectric Generation Using Waste Heat in Steel Works

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  2. Thermoelectric Development at Hi-Z Technology

    SciTech Connect

    Kushch, Aleksandr

    2001-08-05

    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 are capable of producing 1kW of electrical power at 30 V DC during nominal engine operation. Currently the upgraded generator has completed testing in a test cell and starting from August 2001 will be tested on a Diesel truck under typical road and environmental conditions. It is expected that the TEG will be able to supplement the existing shaft driven alternator, resulting in significant fuel saving, generating additional power required by the truck's accessories. The electronic and thermal properties of bulk materials are altered when they are incorporated into quantum wells. Two-dimensional quantum wells have been synthesized by alternating layers of B4C and B9C in one system and alternating layers of Si and Si0.8Ge0.2 in another system. Such nanostructures are being investigated as candidate thermoelectric materials with high figures of merit (Z). The predicted enhancement is attributed to the confined motion of charge carriers and phonons in the two dimensions and separating them from the ion scattering centers. Multilayer quantum well materials development continues with the fabrication of thicker films, evaluation of various substrates to minimize bypass heat loss, and bonding techniques to minimize high contact resistance. Quantum well thermoelectric devices with N-type Si/Si0.8Ge0.2 and P-type B4C/B9C have been fabricated from these films. The test results generated continue to indicate that much higher thermoelectric efficiencies can be achieved in the quantum wells compared to the bulk

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  4. Modeling of concentrating solar thermoelectric generators

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  5. Fabrication of Advanced Thermoelectric Materials by Hierarchical Nanovoid Generation

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1972-01-01

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

  7. Thermoelectric materials development. Final report

    SciTech Connect

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

    1998-09-01

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

  8. CFD modeling of thermoelectric generators in automotive EGR-coolers

    NASA Astrophysics Data System (ADS)

    Högblom, Olle; Andersson, Ronnie

    2012-06-01

    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.

  9. Multiphysics Simulation in the Development of Thermoelectric Energy Harvesting Systems

    NASA Astrophysics Data System (ADS)

    Nesarajah, Marco; Frey, Georg

    2016-03-01

    This contribution presents a model-based development process for thermoelectric energy harvesting systems. Such systems convert thermal energy into electrical energy and produce enough energy to supply low-power devices. Realizations require three main challenges to be solved: to guarantee optimal thermal connection of the thermoelectric generators, to find a good design for the energy harvesting system, and to find an optimal electrical connection. Therefore, a development process is presented here. The process is divided into different steps and supports the developer in finding an optimal thermoelectric energy harvesting system for a given heat source and given objectives (technical and economical). During the process, several steps are supported by simulation models. Based on developed model libraries in Modelica®/Dymola®, thermal, thermoelectrical, electrical, and control components can be modeled, integrated into different variants, and verified step by step before the system is physically built and finally validated. The process is illustrated by an example through all the steps.

  10. Radioisotope thermoelectric generator transport trailer system

    NASA Astrophysics Data System (ADS)

    Ard, Kevin E.; King, David A.; Leigh, Harley; Satoh, Juli A.

    1995-01-01

    The Radioisotope Thermoelectric Generator (RTG) Transportation System, designated as System 100, comprises four major systems. The four major systems are designated as the Packaging System (System 120), Trailer System (System 140), Operations and Ancillary Equipment System (System 160), and Shipping and Receiving Facility Transport System (System 180). Packaging System (System 120), including the RTG packaging is licensed (regulatory) hardware; it is certified by the U.S. Department of Energy to be in accordance with Title 10, Code of Federal Regulations, Part 71 (10 CFR 71). System 140, System 160, and System 180 are nonlicensed (nonregulatory) hardware.

  11. Radioisotope thermoelectric generator transport trailer system

    SciTech Connect

    Ard, K.E.; King, D.A.; Leigh, H.; Satoh, J.A.

    1995-01-20

    The Radioisotope Thermoelectric Generator (RTG) Transportation System, designated as System 100, comprises four major systems. The four major systems are designated as the Packaging System (System 120), Trailer System (System 140), Operations and Ancillary Equipment System (System 160), and Shipping and Receiving Facility Transport System (System 180). Packaging System (System 120), including the RTG packaging is licensed (regulatory) hardware; it is certified by the U.S. Department of Energy to be in accordance with Title 10, {ital Code} {ital of} {ital Federal} {ital Regulations}, Part 71 (10 CFR 71). System 140, System 160, and System 180 are nonlicensed (nonregulatory) hardware. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}

  12. Cooling radioisotope thermoelectric generators in the Shuttle

    NASA Technical Reports Server (NTRS)

    Norman, R. M.

    1978-01-01

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

  13. Microscreen radiation shield for thermoelectric generator

    DOEpatents

    Hunt, Thomas K.; Novak, Robert F.; McBride, James R.

    1990-01-01

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

  14. Prototype Combined Heater/Thermoelectric Power Generator for Remote Applications

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  15. Integration of 2-Dimensional Materials for Thermoelectric Power Generation

    NASA Astrophysics Data System (ADS)

    Alsaffar, Fadhel; Al Hussain, Abdulrahman; Amer, Moh. R.; Center of Exclence for Green Nanotechnologies Collaboration; Department of Electrical Engineering (UCLA) Collaboration

    Recent developments in nanomaterial research have significantly progressed the performance of thermoelectric devices. Theoretical investigations of the thermoelectic properties of 2-Dimentional monolayers demonstrate a high figure of merit (ZT) .. Here, we investigate the integration of these 2-Dimensional materials for power generation applications using solar heat. We show that using black phosphorus monolayer (phosphorene) as the p-type material, and Molybdenum disulfide (MoS2) monolayers as the n-type material, we get an effective figure of merit (ZT) at least (1.5) with a conversion efficiency of 13% at 280oC. Our results suggest that the integration of various 2-Dimensional materials is a promising approach for commercial thermoelectric power generation applications.

  16. The Feasibility of a Current-Source Thermoelectric Power Generator and Its Corresponding Structure Design

    NASA Astrophysics Data System (ADS)

    Wu, Guangxi; Yu, Xiong

    2015-06-01

    Traditional thermoelectric power generators consist of thermoelectric elements connected electrically in series and thermally in parallel. Current flowing inside the thermoelectric power generator is conventionally considered to be driven by the Seebeck effect-induced electric field and the output voltage-induced reverse electric field. This paper proposes a more comprehensive model that implies that current is also driven by chemical potential and carrier density variation. Therefore, the thermoelectric power generator can be treated as a current-source power supplier when the current driven by carrier density variation dominates. This paper performs holistic finite element implementation of the new holistic model where a thermoelectric power generator unit behaves like a current-source while the working temperature conditions maintain stability. This result validates that the thermoelectric element shows the behaviors of a current-source power supply under certain conditions. This discovery brings a new perspective on the behaviors of thermoelectric elements, which potentially will lead to the development of novel thermoelectric power generator design.

  17. Development of Thermoelectric Fibers for Miniature Thermoelectric Devices

    NASA Astrophysics Data System (ADS)

    Ren, Fei; Menchhofer, Paul; Kiggans, James; Wang, Hsin

    2016-03-01

    Miniature thermoelectric (TE) devices may be used in a variety of applications such as power sources of small sensors, temperature regulation of precision electronics, etc. Reducing the size of TE elements may also enable design of novel devices with unique form factor and higher device efficiency. Current industrial practice of fabricating TE devices usually involves mechanical removal processes that not only lead to material loss but also limit the geometry of the TE elements. In this project, we explored a powder-processing method for the fabrication of TE fibers with large length-to-area ratio, which could be potentially used for miniature TE devices. Powders were milled from Bi2Te3-based bulk materials and then mixed with a thermoplastic resin dissolved in an organic solvent. Through an extrusion process, flexible, continuous fibers with sub-millimeter diameters were formed. The polymer phase was then removed by sintering. Sintered fibers exhibited similar Seebeck coefficients to the bulk materials. However, their electrical resistivity was much higher, which might be related to the residual porosity and grain boundary contamination. Prototype miniature uni-couples fabricated from these fibers showed a linear I- V behavior and could generate millivolt voltages and output power in the nano-watt range. Further development of these TE fibers requires improvement in their electrical conductivities, which needs a better understanding of the causes that lead to the low conductivity in the sintered fibers.

  18. Development of thermoelectric fibers for miniature thermoelectric devices

    DOE PAGESBeta

    Ren, Fei; Menchhofer, Paul A.; Kiggans, Jr., James O.; Wang, Hsin

    2016-09-23

    Miniature thermoelectric (TE) devices may be used in a variety of applications such as power sources of small sensors, temperature regulation of precision electronics, etc. Reducing the size of TE elements may also enable design of novel devices with unique form factor and higher device efficiency. Current industrial practice of fabricating TE devices usually involves mechanical removal processes that not only lead to material loss but also limit the geometry of the TE elements. In this project, we explored a powder-processing method for the fabrication of TE fibers with large length-to-area ratio, which could be potentially used for miniature TEmore » devices. Powders were milled from Bi2Te3-based bulk materials and then mixed with a thermoplastic resin dissolved in an organic solvent. Through an extrusion process, flexible, continuous fibers with sub-millimeter diameters were formed. The polymer phase was then removed by sintering. Sintered fibers exhibited similar Seebeck coefficients to the bulk materials. Moreover, their electrical resistivity was much higher, which might be related to the residual porosity and grain boundary contamination. Prototype miniature uni-couples fabricated from these fibers showed a linear I-V behavior and could generate millivolt voltages and output power in the nano-watt range. Further development of these TE fibers requires improvement in their electrical conductivities, which needs a better understanding of the causes that lead to the low conductivity in the sintered fibers.« less

  19. Transient Thermoelectric Generator: An Active Load Story

    NASA Astrophysics Data System (ADS)

    Stockholm, J. G.; Goupil, C.; Maussion, P.; Ouerdane, H.

    2015-06-01

    Under stationary conditions, the optimization of maximum power output and efficiency of thermoelectric generators (TEG) is a well-known subject. Use of a finite-time thermodynamics (FTT) approach to the description of TEGs has demonstrated that there exists a closed feedback effect between the output electrical load value and the entering heat current. From the practical point of view, this effect is strongly evidenced by the use of direct current (DC-to-DC) converters as active loads. Both transient conditions and FTT contribute to a complex landscape of the optimization of the power and efficiencies of a TEG. It has been claimed that the use of inductive load may lead to a strong enhancement of the efficiency, and the frequency response of a TEG as a band-pass filter has also been recently reported. We consider these results using a classical linear Onsager approach of a TEG operating under transient conditions. We show that a trans-admittance may be defined as a coupling element between the input and the output, leading to the observed electric-to-thermal feedback. We discuss recent experiments on a TEG connected to an active load, which is reported to boast an efficiency exceeding the usual stationary DC thermoelectric efficiency.

  20. End-on radioisotope thermoelectric generator impact tests

    NASA Astrophysics Data System (ADS)

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

    1997-01-01

    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). 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.

  1. End-on radioisotope thermoelectric generator impact tests

    SciTech Connect

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

    1997-01-01

    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. {copyright} {ital 1997 American Institute of Physics.}

  2. End-on radioisotope thermoelectric generator impact tests

    SciTech Connect

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

    1997-01-01

    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.

  3. Fiber optic signal amplifier using thermoelectric power generation

    DOEpatents

    Hart, M.M.

    1995-04-18

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

  4. Fiber optic signal amplifier using thermoelectric power generation

    DOEpatents

    Hart, M.M.

    1993-01-01

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

  5. Fiber optic signal amplifier using thermoelectric power generation

    DOEpatents

    Hart, Mark M.

    1995-01-01

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

  6. A power conditioning system for radioisotope thermoelectric generator energy sources

    NASA Technical Reports Server (NTRS)

    Gillis, J. A., Jr.

    1974-01-01

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

  7. Thermoelectric generator and method for the fabrication thereof

    DOEpatents

    Benson, David K.; Tracy, C. Edwin

    1987-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  9. Experimental Investigation on Effect of Adhesives on Thermoelectric Generator Performance

    NASA Astrophysics Data System (ADS)

    Singh, Baljit; Remeli, Muhammad Fairuz; Chet, Ding Lai; Oberoi, Amandeep; Date, Abhijit; Akbarzadeh, Aliakbar

    2015-06-01

    Thermoelectric generators (TEGs) convert heat energy into electricity. Currently, these devices are attached to heat exchangers by means of mechanical devices such as clamps or fixtures with nuts and bolts. These mechanical devices are not suitable for use in harsh environments due to problems with rusting and maintenance. To eliminate the need for such mechanical devices, various kinds of adhesives used to attach thermoelectric generators to heat exchangers are investigated experimentally in this work. These adhesives have been selected based on their thermal properties and also their stability to work in harsh environments to avoid damage to the integrity of the attachment over long periods of time. Stainless-steel plates were attached to a thermoelectric generator using the adhesives. The introduction of the adhesive as a means of attachment for thermoelectric generators contributes to increase the thermal resistance to heat transfer across the TEG. The adhesive layers increased the thermal resistance of the thermoelectric generator by 16% to 109%. This work examines the effect of the adhesives on the thermal performance and power output of a single thermoelectric generator for various heat inputs.

  10. Thermal Design of a Thermoelectric Micro-Generator

    NASA Astrophysics Data System (ADS)

    Hama, S.; Yabuki, T.; Tranchant, L.; Miyazaki, K.

    2015-12-01

    In this study, we fabricated micro thermoelectric power generator using freestanding film substrate, and we evaluated the performance of the generator from the standpoint of thermoelectric performance and thermal design. We fabricated a SiNx free-standing film substrate about 5 μm thick on Si wafer, using MEMS processes. Then, we prepared for both p and n type of bismuth telluride thermoelectric thin films by using a coaxial type vacuum arc evaporation method, and annealed for one hour at 573 K. As an electrode, Cu was deposited using a vacuum deposition method. We fabricated the thermoelectric power generator of 5 mm × 5 mm using a shadow mask for the patterning. The fabricated generator can create temperature difference of 22.3 K due to its high thermal resistance of the structure when the heat source temperature is 373 K. The exergy of the thermoelectric device is up to 7%. Therefore, the generator can convert about 0.4% of thermal energy into electric energy, even though the material performance is low with ZT = 0.28. The conversion efficiency is much higher than that of the conventional Π type thermoelectric module. It was possible to get higher performance by the thermal design, which is a more simple way than an improvement of ZT.

  11. An overview of the Radioisotope Thermoelectric Generator Transportation System Program

    SciTech Connect

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

    1996-03-01

    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.}

  12. An overview of the Radioisotope Thermoelectric Generator Transportation System Program

    NASA Astrophysics Data System (ADS)

    McCoy, John C.; Becker, David L.

    1996-03-01

    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'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.

  13. An overview of the Radioisotope Thermoelectric Generator Transporation System Program

    SciTech Connect

    McCoy, J.C.

    1995-10-01

    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.

  14. Critical Concentration Ratio for Solar Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    ur Rehman, Naveed; Siddiqui, Mubashir Ali

    2016-06-01

    A correlation for determining the critical concentration ratio (CCR) of solar concentrated thermoelectric generators (SCTEGs) has been established, and the significance of the contributing parameters is discussed in detail. For any SCTEG, higher concentration ratio leads to higher temperatures at the hot side of modules. However, the maximum value of this temperature for safe operation is limited by the material properties of the modules and should be considered as an important design constraint. Taking into account this limitation, the CCR can be defined as the maximum concentration ratio usable for a particular SCTEG. The established correlation is based on factors associated with the material and geometric properties of modules, thermal characteristics of the receiver, installation site attributes, and thermal and electrical operating conditions. To reduce the number of terms in the correlation, these factors are combined to form dimensionless groups by applying the Buckingham Pi theorem. A correlation model containing these groups is proposed and fit to a dataset obtained by simulating a thermodynamic (physical) model over sampled values acquired by applying the Latin hypercube sampling (LHS) technique over a realistic distribution of factors. The coefficient of determination and relative error are found to be 97% and ±20%, respectively. The correlation is validated by comparing the predicted results with literature values. In addition, the significance and effects of the Pi groups on the CCR are evaluated and thoroughly discussed. This study will lead to a wide range of opportunities regarding design and optimization of SCTEGs.

  15. Estimation of Thermoelectric Generator Performance by Finite Element Modeling

    NASA Astrophysics Data System (ADS)

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

    2010-09-01

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

  16. Thermoelectric power generator for variable thermal power source

    SciTech Connect

    Bell, Lon E; Crane, Douglas Todd

    2015-04-14

    Traditional power generation systems using thermoelectric power generators are designed to operate most efficiently for a single operating condition. The present invention provides a power generation system in which the characteristics of the thermoelectrics, the flow of the thermal power, and the operational characteristics of the power generator are monitored and controlled such that higher operation efficiencies and/or higher output powers can be maintained with variably thermal power input. Such a system is particularly beneficial in variable thermal power source systems, such as recovering power from the waste heat generated in the exhaust of combustion engines.

  17. Tests and evaluation of multihundred watt thermoelectric generators at JPL

    NASA Technical Reports Server (NTRS)

    Rouklove, P.

    1977-01-01

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

  18. Design and analysis of solar thermoelectric power generation system

    NASA Astrophysics Data System (ADS)

    Vatcharasathien, Narong; Hirunlabh, Jongjit; Khedari, Joseph; Daguenet, Michel

    2005-09-01

    This article reports on the design and performance analysis of a solar thermoelectric power generation plant (STEPG). The system considers both truncated compound parabolic collectors (CPCs) with a flat receiver and conventional flat-plate collectors, thermoelectric (TE) cooling and power generator modules and appropriate connecting pipes and control devices. The design tool uses TRNSYS IIsibat-15 program with a new component we developed for the TE modules. The main input data of the system are the specifications of TE module, the maximum hot side temperature of TE modules, and the desired power output. Examples of the design using truncated CPC and flat-plate collectors are reported and discussed for various slope angle and half-acceptance angle of CPC. To minimize system cost, seasonal adjustment of the slope angle between 0° and 30° was considered, which could give relatively high power output under Bangkok ambient condition. Two small-scale STEPGs were built. One of them uses electrical heater, whereas the other used a CPC with locally made aluminum foil reflector. Measured data showed reasonable agreement with the model outputs. TE cooling modules were found to be more appropriate. Therefore, the TRNSYS software and the developed TE component offer an extremely powerful tool for the design and performance analysis of STEPG plant.

  19. Investigation of Maximum Power Point Tracking for Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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.

  20. Nanostructured Bulk Thermoelectric Generator for Efficient Power Harvesting for Self-powered Sensor Networks

    SciTech Connect

    Zhang, Yanliang; Butt, Darryl; Agarwal, Vivek

    2015-07-01

    The objective of this Nuclear Energy Enabling Technology research project is to develop high-efficiency and reliable thermoelectric generators for self-powered wireless sensors nodes utilizing thermal energy from nuclear plant or fuel cycle. The power harvesting technology has crosscutting significance to address critical technology gaps in monitoring nuclear plants and fuel cycle. The outcomes of the project will lead to significant advancement in sensors and instrumentation technology, reducing cost, improving monitoring reliability and therefore enhancing safety. The self-powered wireless sensor networks could support the long-term safe and economical operation of all the reactor designs and fuel cycle concepts, as well as spent fuel storage and many other nuclear science and engineering applications. The research is based on recent breakthroughs in high-performance nanostructured bulk (nanobulk) thermoelectric materials that enable high-efficiency direct heat-to-electricity conversion over a wide temperature range. The nanobulk thermoelectric materials that the research team at Boise State University and University of Houston has developed yield up to a 50% increase in the thermoelectric figure of merit, ZT, compared with state-of-the-art bulk counterparts. This report focuses on the selection of optimal thermoelectric materials for this project. The team has performed extensive study on two thermoelectric materials systems, i.e. the half-Heusler materials, and the Bismuth-Telluride materials. The report contains our recent research results on the fabrication, characterization and thermoelectric property measurements of these two materials.

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  2. All dispenser printed flexible 3D structured thermoelectric generators

    NASA Astrophysics Data System (ADS)

    Cao, Z.; Shi, J. J.; Torah, R. N.; Tudor, M. J.; Beeby, S. P.

    2015-12-01

    This work presents a vertically fabricated 3D thermoelectric generator (TEG) by dispenser printing on flexible polyimide substrate. This direct-write technology only involves printing of electrodes, thermoelectric active materials and structure material, which needs no masks to transfer the patterns onto the substrate. The dimension for single thermoelectric element is 2 mm × 2 mm × 0.5 mm while the distance between adjacent cubes is 1.2 mm. The polymer structure layer was used to support the electrodes which are printed to connect the top ends of the thermoelectric material and ensure the flexibility as well. The advantages and the limitations of the dispenser printed 3D TEGs will also be evaluated in this paper. The proposed method is potential to be a low-cost and scalable fabrication solution for TEGs.

  3. High-Temperature High-Efficiency Solar Thermoelectric Generators

    SciTech Connect

    Baranowski, LL; Warren, EL; Toberer, ES

    2014-03-01

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

  4. Use of thermoelectric generator for water flow metering

    NASA Astrophysics Data System (ADS)

    Alothman, Abdulmohsen A.; Zakaria, Mohamed Y.; Hajj, Muhammad R.; Masri, Sami F.

    2016-07-01

    We propose using a thermoelectric generator as a flow meter without requiring additional components. We do so by relating the power generated from the flow of hot water in a pipe to the flow rate. The results show that the steady state values of the power and voltage are more or less independent of the flow rate. On the other hand, the peak power varies significantly with the flow rate. As such, we develop through data analysis a relation between the nondimensional harvested peak power and the Reynolds number. Different sets of experiments are performed to assess the dependence of the developed relation on the boundary conditions. An equation governing this relation is obtained. The proposed approach provides a self-powered monitoring device for quantifying flow rates in pipes conveying hot water.

  5. Performance testing of thermoelectric generators at JPL. [for space applications

    NASA Technical Reports Server (NTRS)

    Rouklove, P.; Truscello, V. C.

    1975-01-01

    Several thermoelectric generators, ranging in output power from 170 watts to microwatts, are undergoing testing at JPL. They represent a wide range of technologies using advanced PbTe, SiGe and cascaded PbTe and BiTe thermoelectric materials. Several of these generators are of an advanced concept while others are representative of the Nimbus, Transit, Viking and the multi-hundred-watt (MHW) technology. Of interest is the behavior of generators which have been tested for times in excess of 60,000 hours.

  6. Simulations for the Development of Thermoelectric Measurements

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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

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

    SciTech Connect

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

    2005-03-16

    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 PACCAR'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

  8. Integrating Phase-Change Materials into Automotive Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  9. Thermoelectric efficiency of (1 - x)(GeTe) x(Bi2Se0.2Te2.8) and implementation into highly performing thermoelectric power generators.

    PubMed

    Koenig, J; Winkler, M; Dankwort, T; Hansen, A-L; Pernau, H-F; Duppel, V; Jaegle, M; Bartholomé, K; Kienle, L; Bensch, W

    2015-02-14

    Here we report for the first time on a complete simulation assisted "material to module" development of a high performance thermoelectric generator (TEG) based on the combination of a phase change material and established thermoelectrics yielding the compositions (1 - x)(GeTe) x(Bi(2)Se(0.2)Te(2.8)). For the generator design our approach for benchmarking thermoelectric materials is demonstrated which is not restricted to the determination of the intrinsically imprecise ZT value but includes the implementation of the material into a TEG. This approach is enabling a much more reliable benchmarking of thermoelectric materials for TEG application. Furthermore we analyzed the microstructure and performance close to in-operandi conditions for two different compositions in order to demonstrate the sensitivity of the material against processing and thermal cycling. For x = 0.038 the microstructure of the as-prepared material remains unchanged, consequently, excellent and stable thermoelectric performance as prerequisites for TEG production was obtained. For x = 0.063 we observed strain phenomena for the pristine state which are released by the formation of planar defects after thermal cycling. Consequently the thermoelectric performance degrades significantly. These findings highlight a complication for deriving the correlation of microstructure and properties of thermoelectric materials in general. PMID:25559337

  10. Modeling a Thermoelectric Generator Applied to Diesel Automotive Heat Recovery

    NASA Astrophysics Data System (ADS)

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

    2010-09-01

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

  11. Thermodynamic studies and maximum power point tracking in thermoelectric generator-thermoelectric cooler combined system

    NASA Astrophysics Data System (ADS)

    Manikandan, S.; Kaushik, S. C.

    2015-04-01

    Thermoelectric generator (TEG) operated thermoelectric cooler (TEC) is a highly compatible combination for low-cooling power application. The conventional TEG-TEC combined systems have low operating efficiency and low cooling power because maximum power output from the TEG is not fully utilized. This paper proposes and analyses the combined system with maximum power point tracking technique (MPPT) to maximize the cooling power and overall efficiency. This paper also presents the effect of TEG, TEC source temperature and the effect of heat transfer area in the performance of the combined system. The thermodynamic models of the combined system are developed in MATLAB simulink environment with temperature dependent material properties and analysed for variable operating temperatures. It has been found that, in the irreversible thermodynamic model of the combined system with MPPT, when the hot and cold side of TEG and TEC are kept at a temperature difference of 150 K and 10 K respectively, the power output of TEG increases from 20.49 W to 43.92 W, cooling power of TEC increases from 32.66 W to 46.51 W and the overall combined system efficiency increases from 2.606% to 4.375% respectively when compared with the irreversible combined system without MPPT. The characteristics improvements obtained by this practice in the combined system for the above mentioned operating conditions is also true for other range of operating temperatures. It is also been observed that the external irreversibilities decreases the cooling power and the overall system efficiency of the combined system by 36.49% and by 16.9% respectively.

  12. Emitted radiation characteristics of plutonium dioxide radioisotope thermoelectric generators

    NASA Technical Reports Server (NTRS)

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

    1971-01-01

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

  13. Parametric Optimization of Thermoelectric Generators for Waste Heat Recovery

    NASA Astrophysics Data System (ADS)

    Huang, Shouyuan; Xu, Xianfan

    2016-06-01

    This paper presents a methodology for design optimization of thermoelectric-based waste heat recovery systems called thermoelectric generators (TEGs). The aim is to maximize the power output from thermoelectrics which are used as add-on modules to an existing gas-phase heat exchanger, without negative impacts, e.g., maintaining a minimum heat dissipation rate from the hot side. A numerical model is proposed for TEG coupled heat transfer and electrical power output. This finite-volume-based model simulates different types of heat exchangers, i.e., counter-flow and cross-flow, for TEGs. Multiple-filled skutterudites and bismuth-telluride-based thermoelectric modules (TEMs) are applied, respectively, in higher and lower temperature regions. The response surface methodology is implemented to determine the optimized TEG size along and across the flow direction and the height of thermoelectric couple legs, and to analyze their covariance and relative sensitivity. A genetic algorithm is employed to verify the globality of the optimum. The presented method will be generally useful for optimizing heat-exchanger-based TEG performance.

  14. Molybdenum-platinum-oxide electrodes for thermoelectric generators

    DOEpatents

    Schmatz, Duane J.

    1990-01-01

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

  15. Engineering development testing of the GPHS-RTG converter. [General Purpose Heat Source-Radioisotope Thermoelectric Generator

    SciTech Connect

    Cockfield, R.D.

    1981-01-01

    The GPHS-RTG will provide electrical power for the Galileo orbiter and for the two spacecraft of the International Solar Polar Mission. The GPHS-RTG consists of two primary assemblies: the General Purpose Heat Source, and the converter. This paper deals only with the converter, and highlights engineering tests that provide support for its design development.

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

    NASA Astrophysics Data System (ADS)

    Arias, F. J.

    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 (α, n) reactions between the α particles from Pu-238 and beryllium, lithium or other low-Z isotope, extracting the maximum advantage and performance from the precious α 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).

  17. Increasing the Efficiency of the Multi-mission Radioisotope Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Holgate, Tim C.; Bennett, Russell; Hammel, Tom; Caillat, Thierry; Keyser, Steve; Sievers, Bob

    2015-06-01

    The National Aeronautics and Space Administration's Mars Science Laboratory terrestrial rover, Curiosity, has recently completed its first Martian year (687 Earth days) during which it has provided a wealth of information and insight into the red planet's atmosphere and geology. The success of this mission was made possible in part by the reliable electrical power provided by its onboard thermoelectric power source—the multi-mission radioisotope thermoelectric generator (MMRTG). In an effort to increase the output power and efficiency of these generators, a newly designed enhanced MMRTG (eMMRTG) that will utilize the more efficient skutterudite-based thermoelectric materials has been conceptualized and modeled, and is now being developed. A discussion of the motivations, modeling results and key design factors are presented and discussed.

  18. Long term tests of a SNAP-19 thermoelectric generator.

    NASA Technical Reports Server (NTRS)

    Rouklove, P.; Truscello, V.

    1972-01-01

    Results of tests performed on a SNAP 19 thermoelectric generator, SN-20. The SN-20 generator was tested for approximately 37,000 hours using electrical heating to simulate the heat released by isotope decay. After 27,000 hours of operation the output power from the generator decreased to approximately 1/3 of the beginning of life value while the internal resistance increased by a factor of 5. Analysis of the test results, confirmed by preliminary metallographic examination, indicated that the output power degradation was the result of excessive sublimation of the thermoelectric material and loss of the hot junction bond due to the depletion of the internal cover gas. This also resulted in excessive junction temperatures. Comparison is made with the behavior observed from the two flight generators and a tentative conclusion is advanced as to the reason for their failure.

  19. Pyroshock Testing of the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG)

    NASA Technical Reports Server (NTRS)

    Woerner, David; Fleurial, Jean-Pierre; Bennett, Russell; Hammel, Tom; Otting, William

    2013-01-01

    The Mars Science Laboratory (MSL) Multi-Mission Radioisotope Thermoelectric Generator, or MMRTG, was developed by the Department Of Energy to a set of requirements from multiple NASA mission concepts. Those concepts included deep space missions to the outer planets as well as missions to Mars. The synthesis of that diverse set of requirements addressed functional as well as environmental requirements.

  20. Electric energy production by particle thermionic-thermoelectric power generators

    NASA Technical Reports Server (NTRS)

    Oettinger, P. E.

    1980-01-01

    Thermionic-thermoelectric power generators, composed of a thin layer of porous, low work function material separating a heated emitter electrode and a cooler collector electrode, have extremely large Seebeck coefficients of over 2 mV/K and can provide significant output power. Preliminary experiments with 20-micron thick (Ba Sr Ca)O coatings, limited by evaporative loss to temperatures below 1400 K, have yielded short circuit current densities of 500 mA/sq cm and power densities of 60 mW/ sq cm. Substantially more output is expected with cesium-coated refractory oxide particle coatings operating at higher temperatures. Practical generators will have thermal-to-electrical efficiencies of 10 to 20%. Further increases can be gained by cascading these high-temperature devices with lower temperature conventional thermoelectric generators.

  1. Design concepts of solar thermoelectric generators in space applications

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  2. Thermoelectric Generator Used in Fire-Alarm Temperature Sensing

    NASA Astrophysics Data System (ADS)

    Wu, Wenchang; Du, Zhengliang; Cui, Jiaolin; Shi, Zhongtao; Deng, Yuan

    2015-06-01

    Here we present a thermoelectric (TE) generator used in fire-alarm temperature sensing. The TE module, a core component of this generator, has a sandwich-like structure consisting of a Cu/Sn95Ag5/coated Ni/sprayed Ni/TE/sprayed Ni/coated Ni/Sn95Ag5/Cu multilayer that exhibits a low internal resistance of 5.5 Ω to 5.9 Ω and a contact resistance of 0.51 Ω to 0.91 Ω at room temperature (RT), enabling the TE generator to attain an open-circuit voltage ( V op) of 1.50 V at RT and 2.97 V at ~90°C. Moreover, its maximum output power ( p max) was estimated to be 11.6 mW and 428.7 mW, respectively, for a temperature difference (Δ T) of 9.3°C and 52.9°C. These values are comparable to those for the bulk TE generator developed by Thermonamic. According to these figures, we obtain corresponding power densities of ~7.25 × 103 nW/mm2 and 2.68 × 105 nW/mm2, respectively. Although there is still much room to improve the performance of the generator when the source temperature rises above 90°C, the output voltages and maximum output powers attained in the current testing conditions are large enough to drive small electronic devices such as fire-alarm systems etc. Therefore, it is believed that the fabrication technology and designed structure of the generator are appropriate for such applications.

  3. Analytical predictions of RTG power degradation. [Radioisotope Thermoelectric Generator

    NASA Technical Reports Server (NTRS)

    Noon, E. L.; Raag, V.

    1979-01-01

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

  4. Computer program for the transient analysis of radioisotope thermoelectric generators.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  5. Optimization of Cooling Unit Design for Automotive Exhaust-Based Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    Su, C. Q.; Xu, M.; Wang, W. S.; Deng, Y. D.; Liu, X.; Tang, Z. B.

    2015-06-01

    Integrating a thermoelectric cooler (TEC) into the engine cooling system has various advantages including reducing additional mechanical parts, and saving energy and space for automotive applications. Based on performance parameters of the engine and thermoelectric modules, three different TEC configurations called plate-shape, stripe-shape, and diamond-shape are constructed with development of simulations of the different TECs and the performance of the circulating coolant. Based on these simulations, the velocity, pressure, and temperature fields of the coolant are obtained for further research. Besides, the temperature of the TEC and the output power of the thermoelectric generator (TEG) are acquired experimentally. Comparing the working performance of the different TECs, the simulation and experimental results show that the TEG using the diamond-shaped TEC achieves a relatively ideal performance. Finally, some measures are proposed to improve the cooling system, providing guidelines for future research.

  6. Aspects of Protonic Ionic Liquid as Electrolyte in Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    Laux, Edith; Uhl, Stefanie; Journot, Tony; Brossard, Julien; Jeandupeux, Laure; Keppner, Herbert

    2016-04-01

    The Seebeck coefficient (S E) or thermopower and power output have been measured in a series of 16 ionic liquids (ILs). Thermoelectric current extraction is assisted by a dissolved redox couple (I2/LiI) added to the IL. The experiments were carried out in a thermoelectric cell where the IL is packaged between two electrodes. A large range of Seebeck coefficients and power outputs could be observed. The highest S E was measured for protonic ILs, reaching a value of 968 μV/K. Moreover, the maximal power output of an IL-based thermoelectric generator and the polarity of its electrodes depend on the concentration of the redox-active species in the IL. The power output of the generator increased continuously with the redox concentration up to a maximum value (at 0.4 mol/L) but decayed for higher concentrations. We showed that an IL with high S E [linked to open-circuit voltage (V OC)] does not necessarily lead to high power output; rather, it is carrier transport and extraction that determine the generator power. Surprisingly, the carrier extraction is not highest at the maximum electrode temperature difference; the power output observed for a given electrode temperature difference can be further increased by heating up the cold electrode in spite of the consequent reduction in the total temperature difference between the electrodes.

  7. Aspects of Protonic Ionic Liquid as Electrolyte in Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    Laux, Edith; Uhl, Stefanie; Journot, Tony; Brossard, Julien; Jeandupeux, Laure; Keppner, Herbert

    2016-07-01

    The Seebeck coefficient ( S E) or thermopower and power output have been measured in a series of 16 ionic liquids (ILs). Thermoelectric current extraction is assisted by a dissolved redox couple (I2/LiI) added to the IL. The experiments were carried out in a thermoelectric cell where the IL is packaged between two electrodes. A large range of Seebeck coefficients and power outputs could be observed. The highest S E was measured for protonic ILs, reaching a value of 968 μV/K. Moreover, the maximal power output of an IL-based thermoelectric generator and the polarity of its electrodes depend on the concentration of the redox-active species in the IL. The power output of the generator increased continuously with the redox concentration up to a maximum value (at 0.4 mol/L) but decayed for higher concentrations. We showed that an IL with high S E [linked to open-circuit voltage ( V OC)] does not necessarily lead to high power output; rather, it is carrier transport and extraction that determine the generator power. Surprisingly, the carrier extraction is not highest at the maximum electrode temperature difference; the power output observed for a given electrode temperature difference can be further increased by heating up the cold electrode in spite of the consequent reduction in the total temperature difference between the electrodes.

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

    PubMed

    Chang, Ho; Yu, Zhi-Rong

    2012-08-01

    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

  9. Progress in the Development of Segmented Thermoelectric Unicouples at the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    A new verison of a segmented thermoelectric unicouple incorporating advanced thermoelectric materials with superior thermoelectric figures of merit has been recetly proposed and is currently under development at the Jet Propulsion Laboratory (JPL).

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

    SciTech Connect

    Pugh, B.K.

    1997-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Pugh, Barry K.

    1997-01-01

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

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

    SciTech Connect

    Pugh, Barry K.

    1997-01-10

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

  13. Performance of the 1 kW thermoelectric generator for diesel engines

    NASA Astrophysics Data System (ADS)

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

    1994-08-01

    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.

  14. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

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

    1998-01-15

    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 converter housing, failure of one fueled clad, and release of a small quantity of fuel.

  15. Radioisotope thermoelectric generator/thin fragment impact test

    NASA Astrophysics Data System (ADS)

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

    1998-01-01

    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.

  16. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

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

    1998-01-01

    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 converter housing, failure of one fueled clad, and release of a small quantity of fuel. {copyright} {ital 1998 American Institute of Physics.}

  17. High-efficiency photovoltaic technology including thermoelectric generation

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  18. Acoustic Optimization of Automotive Exhaust Heat Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  19. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

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

    1998-12-31

    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.

  20. Anisotropic thermoelectric behavior in armchair and zigzag mono- and fewlayer MoS2 in thermoelectric generator applications.

    PubMed

    Arab, Abbas; Li, Qiliang

    2015-01-01

    In this work, we have studied thermoelectric properties of monolayer and fewlayer MoS2 in both armchair and zigzag orientations. Density functional theory (DFT) using non-equilibrium Green's function (NEGF) method has been implemented to calculate the transmission spectra of mono- and fewlayer MoS2 in armchair and zigzag directions. Phonon transmission spectra are calculated based on parameterization of Stillinger-Weber potential. Thermoelectric figure of merit, ZT, is calculated using these electronic and phonon transmission spectra. In general, a thermoelectric generator is composed of thermocouples made of both n-type and p-type legs. Based on our calculations, monolayer MoS2 in armchair orientation is found to have the highest ZT value for both p-type and n-type legs compared to all other armchair and zigzag structures. We have proposed a thermoelectric generator based on monolayer MoS2 in armchair orientation. Moreover, we have studied the effect of various dopant species on thermoelectric current of our proposed generator. Further, we have compared output current of our proposed generator with those of Silicon thin films. Results indicate that thermoelectric current of MoS2 armchair monolayer is several orders of magnitude higher than that of Silicon thin films. PMID:26333948

  1. Anisotropic thermoelectric behavior in armchair and zigzag mono- and fewlayer MoS2 in thermoelectric generator applications

    NASA Astrophysics Data System (ADS)

    Arab, Abbas; Li, Qiliang

    2015-09-01

    In this work, we have studied thermoelectric properties of monolayer and fewlayer MoS2 in both armchair and zigzag orientations. Density functional theory (DFT) using non-equilibrium Green’s function (NEGF) method has been implemented to calculate the transmission spectra of mono- and fewlayer MoS2 in armchair and zigzag directions. Phonon transmission spectra are calculated based on parameterization of Stillinger-Weber potential. Thermoelectric figure of merit, ZT, is calculated using these electronic and phonon transmission spectra. In general, a thermoelectric generator is composed of thermocouples made of both n-type and p-type legs. Based on our calculations, monolayer MoS2 in armchair orientation is found to have the highest ZT value for both p-type and n-type legs compared to all other armchair and zigzag structures. We have proposed a thermoelectric generator based on monolayer MoS2 in armchair orientation. Moreover, we have studied the effect of various dopant species on thermoelectric current of our proposed generator. Further, we have compared output current of our proposed generator with those of Silicon thin films. Results indicate that thermoelectric current of MoS2 armchair monolayer is several orders of magnitude higher than that of Silicon thin films.

  2. Anisotropic thermoelectric behavior in armchair and zigzag mono- and fewlayer MoS2 in thermoelectric generator applications

    PubMed Central

    Arab, Abbas; Li, Qiliang

    2015-01-01

    In this work, we have studied thermoelectric properties of monolayer and fewlayer MoS2 in both armchair and zigzag orientations. Density functional theory (DFT) using non-equilibrium Green’s function (NEGF) method has been implemented to calculate the transmission spectra of mono- and fewlayer MoS2 in armchair and zigzag directions. Phonon transmission spectra are calculated based on parameterization of Stillinger-Weber potential. Thermoelectric figure of merit, ZT, is calculated using these electronic and phonon transmission spectra. In general, a thermoelectric generator is composed of thermocouples made of both n-type and p-type legs. Based on our calculations, monolayer MoS2 in armchair orientation is found to have the highest ZT value for both p-type and n-type legs compared to all other armchair and zigzag structures. We have proposed a thermoelectric generator based on monolayer MoS2 in armchair orientation. Moreover, we have studied the effect of various dopant species on thermoelectric current of our proposed generator. Further, we have compared output current of our proposed generator with those of Silicon thin films. Results indicate that thermoelectric current of MoS2 armchair monolayer is several orders of magnitude higher than that of Silicon thin films. PMID:26333948

  3. Multi-Watt Small Radioisotope Thermoelectric Generator Conceptual Design Study

    NASA Astrophysics Data System (ADS)

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

    2007-01-01

    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.

  4. Analytical thermal model validation for Cassini radioisotope thermoelectric generator

    SciTech Connect

    Lin, E.I.

    1997-12-31

    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 its complex thermal behavior, but displayed large discrepancies against some initial thermal development test data. A careful revalidation effort led to significant modifications and adjustments of the model, which result in a doubling of the radiative heat transfer from the heat source support assemblies to the end domes and bring up the end dome and flange temperature predictions to within 2 C of the pertinent test data. The increased inboard end dome temperature has a considerable impact on thermal control of the spacecraft central body. The validation process offers an example of physically-driven analytical model calibration with test data from not only an electrical simulator but also a nuclear-fueled flight unit, and has established the end dome temperatures of a flight RTG where no in-flight or ground-test data existed before.

  5. Temporal Evolution of Water Use for Thermoelectric Generation

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  6. High Efficiency Thermoelectric Generators Using New Very High Performance Materials

    NASA Astrophysics Data System (ADS)

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

    1994-07-01

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

  7. Close-packed-array (CPA) thermoelectric module development status

    NASA Astrophysics Data System (ADS)

    Brittain, Wayne M.

    The technical approach for modifying the current two-watt radioisotope thermoelectric generator (RTG) thermoelectric module to expand its applicability to more severe terrestrial applications and planetary space missions is to increase the operating temperature capability of the current design as well as reconfigure the minicouple array into a more densely packed CPA arrangement with the objective of increasing the module dynamic loading capability while minimizing size and weight. Use of the CPA technology will result in approximately a factor of five reduction in the area of the thermoelectric module cross section from the current minicouple packing density exemplified by the two-watt module.

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

    SciTech Connect

    Mowery, A.L. Jr.

    1992-12-31

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

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

    DOEpatents

    Mowery, Jr., Alfred L.

    1993-01-01

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

  10. Preliminary design of a miniature thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Bass, John C.

    1994-04-01

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

  11. Power generation from thermoelectric system-embedded Plexiglas for green building technology

    NASA Astrophysics Data System (ADS)

    Inayat, Salman Bin; Hussain, Muhammad Mustafa

    2013-08-01

    Thermoelectric materials embedded through or inside exterior glass windows can act as a viable source of supplemental power in geographic locations where hot weather dominates. This thermoelectricity is generated because of the thermal difference between the high temperature outside and the relatively cold temperature inside. Using physical vapor deposition process, we experimentally verify this concept by embedding bismuth telluride and antimony telluride through the 5 mm Plexiglas to demonstrate 10 nW of thermopower generation with a temperature gradient of 21 °C. Albeit tiny at this point with non-optimized design and development, this concept can be extended for relatively large-scale power generation as an additional power supply for green building technology.

  12. Voltage-Current Curves to Characterize Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    McCarty, Robin; Piper, Robert

    2015-06-01

    There are many ways to experimentally characterize thermoelectric generator (TEG) performance, but most methods provide an incomplete picture. The authors propose using voltage-current ( V- I) curves generated at two different thermal conditions to provide an estimation of maximum power, optimum efficiency, ZT of the device, and thermal resistance due to ceramics and thermal interface materials on the outside of the thermoelectric material (HSR). The two thermal conditions are both steady state, electrically open in one case and electrically shorted in the other, and the heat flow into the device is adjusted to keep the hot-side and cold-side temperatures of the exterior of the module the same in both thermal conditions. The V- I curves are generated from four data points by instantaneously changing the external electrical load such that the TEG does not have time to respond thermally. After these two V- I curves are generated, the performance at any electrical condition can be predicted for the given hot-side and cold-side device temperatures. The authors present experimental data for a bismuth telluride (Bi2Te3) device as verification of this characterization method.

  13. Radioisotope Thermoelectric Generators (RTGs) for Lunar Exploration

    NASA Astrophysics Data System (ADS)

    Woerner, D. F.

    2014-10-01

    A Multi-Mission RTG (MMRTG) is powering the Curiosity rover and was designed as a compact, rugged power source capable of landing on other bodies. NASA is considering development of an enhanced MMRTG and Advanced RTG. More info presented here.

  14. Procurement of a fully licensed radioisotope thermoelectric generator transportation system

    SciTech Connect

    Adkins, H.E.; Bearden, T.E.

    1990-10-01

    A fully licensed transportation system for Radioisotope Thermoelectric Generators and Light-Weight Radioisotope Heater Units is currently being designed and built. The system will comply with all applicable US Department of Transportation regulations without the use of a DOE Alternative.'' The US Department of Transportation has special double containment'' requirements for plutonium. The system packaging uses a doubly contained bell jar'' concept. A refrigerated trailer is used for cooling the high-heat payloads. The same packaging is used for both high- and low-heat payloads. The system is scheduled to be available for use by mid-1992. 4 refs., 4 figs., 2 tabs.

  15. Proposed strontium radiosotope thermoelectric generator fuel encapsulation facility

    SciTech Connect

    Adkins, H.E. )

    1993-01-10

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

  16. Power Delivery from an Actual Thermoelectric Generation System

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

    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.

  18. Wearable and flexible thermoelectric generator with enhanced package

    NASA Astrophysics Data System (ADS)

    Francioso, L.; De Pascali, C.; Taurino, A.; Siciliano, P.; De Risi, A.

    2013-05-01

    Present work shows recent progresses in thin film-based flexible and wearable thermoelectric generator (TEG), finalized to support energy scavenging and local storage for low consumption electronics in Ambient Assisted Living (AAL) applications and buildings integration. The proposed TEG is able to recover energy from heat dispersed into the environment converting a thermal gradient to an effective electrical energy available to power ultra-low consumption devices. A low cost fabrication process based on planar thin-film technology was optimized to scale down the TEG dimensions to micrometer range. The prototype integrates 2778 thermocouples of sputtered Sb2Te3 and Bi2Te3 thin films (1 μm thick) on an area of 25 cm2. The electrical properties of thermoelectric materials were investigated by Van der Pauw measurements. Transfer Length Method (TLM) analysis was performed on three different multi-layer contact schemes in order to select the best solution to use for the definition of the contact pads realized on each section of the thermoelectric array configuration to allow electrical testing of single production areas. Kapton polyimide film was used as flexible substrate in order to add comfortable lightweight and better wearability to the device. The realized TEG is able to autonomously recover the thermal gradient useful to thermoelectric generation thanks to an appropriate package designed and optimized by a thermal analysis based on finite element method (FEM). The proposed package solution consists in coupling the module realized onto Kapton foil to a PDMS layer opportunely molded to thermally insulate TEG cold junctions and enhance the thermal gradient useful for the energy scavenging. Simulations results were compared to experimental tests performed by a thermal infrared camera, in order to evaluate the real performance of the designed package. First tests conducted on the realized TEG indicate that the prototype is able to recover about 5°C between hot and

  19. Design Considerations For A Small Scale Radioisotope Thermoelectric Generator System For European Spacecrafts

    NASA Astrophysics Data System (ADS)

    Deacon, Trevor

    2011-10-01

    Photovoltaic cells are the dominant source of primary power for the majority of current space missions particularly those in earth orbits, where adequate power can be generated using solar arrays. The use of solar arrays may not be advantageous for other missions currently being planned by Europe, for example ultra low solar flux missions to the outer planets. Radioisotope thermoelectric generators (RTGs) offer one solution to this problem. The reported developments are the result of an ESA-funded study, led by the University of Leicester with the Fraunhofer Institute and Astrium Ltd. The study investigated the design of a small-scale RTG in the 1 We to 50 We (electrical output power) range, for Mars and deep space environments, although this paper focuses mainly on the 5 We to 50 We range. This paper will review the fundamentals of thermoelectrics and cover the key design elements of a small scale multi-mission RTG system.

  20. Monolithic oxide-metal composite thermoelectric generators for energy harvesting

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

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

  1. A thermoelectric generator using porous Si thermal isolation.

    PubMed

    Hourdakis, Emmanouel; Nassiopoulou, Androula G

    2013-01-01

    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 μW/cm2 was measured for a 50 μm thick porous Si layer. PMID:24152923

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

    DOEpatents

    Jayadev, T.S.; Benson, D.K.

    1980-05-27

    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 geothermal resources. (WHK)

  3. Influence of nonlinear effects on the efficiency of a thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Rogolino, P.; Sellitto, A.; Cimmelli, V. A.

    2015-10-01

    We propose a nonlinear model for thermoelectric coupling which is based on the thermomass theory for heat conduction. We show that in this model, the second Kelvin relation and the classical Onsager relations are no longer satisfied simultaneously, namely, if one holds, then the other one breaks down, and viceversa. As a function of the different breaking, we evaluate the efficiency of a thermoelectric generator. The influence of the electric-charge gradient on the efficiency of thermoelectric coupling is investigated as well.

  4. A facility to remotely assemble radioisotope thermoelectric generators

    SciTech Connect

    Engstrom, J.W.; Goldmann, L.H.; Truitt, R.W.

    1992-07-01

    Radioisotope Thermoelectric Generators (RTGs) are electrical power sources that use heat from decaying radioisotopes to directly generate electrical power. The RTG assembly process is performed in an inert atmosphere inside a large glovebox, which is surrounded by radiation shielding to reduce exposure to neutron and gamma radiation from the radioisotope heat source. In the past, allowable dose rate limits have allowed direct, manual assembly methods; however, current dose rate limits require a thicker radiation shielding that makes direct, manual assembly infeasible. To minimize RTG assembly process modifications, telerobotic systems are being investigated to perform remote assembly tasks. Telerobotic systems duplicate human arm motion and incorporate force feedback sensitivity to handle objects and tools in a human-like manner. A telerobotic system with two arms and a three-dimensional (3-D) vision system can be used to perform remote RTG assembly tasks inside gloveboxes and cells using unmodified, normal hand tools.

  5. A facility to remotely assemble radioisotope thermoelectric generators

    NASA Astrophysics Data System (ADS)

    Engstrom, John W.; Goldmann, Louis H.; Truitt, Ross W.

    1993-01-01

    Radioisotope Thermoelectric Generators (RTGs) are electrical power sources that use heat from decaying radioisotopes to directly generate electrical power. The RTG assembly process is performed in an inert atmosphere inside a large glovebox, which is surrounded by radiation shielding to reduce exposure to neutron and gamma radiation from the radioisotope heat source. In the past, allowable dose rate limits have allowed direct, manual assembly methods; however, current dose rate limits require a thicker radiation shielding that makes direct, manual assembly infeasible. To minimize RTG assembly process modifications, telerobotic systems are being investigated to perform remote assembly tasks. Telerobotic systems duplicate human arm motion and incorporate force feedback sensitivity to handle objects and tools in a human-like manner. A telerobotic system with two arms and a three-dimensional (3-D) vision system can be used to perform remote RTG assembly tasks inside gloveboxes and cells using unmodified, normal hand tools.

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

    SciTech Connect

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

    2012-03-13

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

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

    NASA Astrophysics Data System (ADS)

    Brady Knowles, C.; Lee, Hohyun

    2012-10-01

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

  8. Heat-Pipe-Associated Localized Thermoelectric Power Generation System

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  9. Thermoelectric generators as self-oscillating heat engines

    NASA Astrophysics Data System (ADS)

    Alicki, Robert

    2016-02-01

    In a previous paper [1] a model of a solar cell was proposed in which the non-periodic source of energy—photon flux—drives the collective periodic motion of electrons in a form of plasma oscillation. Subsequently, plasma oscillations are rectified by the p-n junction diode into dc (work). This approach makes a solar cell similar to standard macroscopic heat motors or turbines which always contain two heat baths, the working medium and the periodically moving piston or rotor. Here, a very similar model is proposed in order to describe the operation principles of thermoelectric generators based either on bimetallic or semiconductor p-n junctions. Again plasma oscillation corresponds to a piston and sunlight is replaced by a hot bath. The mathematical formalism is based on the Markovian master equations which can be derived in a rigorous way from the underlying Hamiltonian models and are consistent with the laws of thermodynamics.

  10. On the Placement of Thermoelectric Generators in Automobiles

    NASA Astrophysics Data System (ADS)

    Korzhuev, M. A.; Katin, I. V.

    2010-09-01

    The placement of thermoelectric generators (TEGs) in vehicles is analyzed, taking into account the interaction of the TEG with the internal combustion engine (ICE). Alternative locations of the TEG directly in the ICE, on the exhaust pipe, and on the cooling system are considered. In all three cases there is a conflict between the two thermal machines, which reduces the total efficiency of the thermodynamic (ICE + TEG) system. It is shown that the cause of the conflict is the low efficiency of the TEG ( η TEG < 0.05) compared with that of the ICE ( η TEG < 0.4); this conflict increases with the net power W e and decreases with increasing η TEG. For this reason, attainable values of W e, as well as waste heat recovery in cars by the TEG, are significantly limited. Also, some problems of finding materials for automotive TEGs and ways to suppress the parasitic Thomson effect in TEG legs are discussed.

  11. Radioisotope thermoelectric generator cooling in the Shuttle bay

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  12. Oligoyne Molecular Junctions for Efficient Room Temperature Thermoelectric Power Generation.

    PubMed

    Sadeghi, Hatef; Sangtarash, Sara; Lambert, Colin J

    2015-11-11

    Understanding phonon transport at a molecular scale is fundamental to the development of high-performance thermoelectric materials for the conversion of waste heat into electricity. We have studied phonon and electron transport in alkane and oligoyne chains of various lengths and find that, due to the more rigid nature of the latter, the phonon thermal conductances of oligoynes are counterintuitively lower than that of the corresponding alkanes. The thermal conductance of oligoynes decreases monotonically with increasing length, whereas the thermal conductance of alkanes initially increases with length and then decreases. This difference in behavior arises from phonon filtering by the gold electrodes and disappears when higher-Debye-frequency electrodes are used. Consequently a molecule that better transmits higher-frequency phonon modes, combined with a low-Debye-frequency electrode that filters high-energy phonons is a viable strategy for suppressing phonon transmission through the molecular junctions. The low thermal conductance of oligoynes, combined with their higher thermopower and higher electrical conductance lead to a maximum thermoelectric figure of merit of ZT = 1.4, which is several orders of magnitude higher than that of alkanes. PMID:26458053

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  14. Si Thermoelectric Power Generator with an Unconventional Structure

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  15. High efficiency thermoelectric power generation using Zintl-type materials

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  16. Development of advanced thermoelectric materials, phase A

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Work performed on the chemical system characterized by chrome sulfide, chrome selenide, lanthanum selenide, and lanthanum sulfide is described. Most materials within the chemical systems possess the requisites for attractive thermoelectric materials. The preparation of the alloys is discussed. Graphs show the Seebeck coefficient, electrical resistivity, and thermal conductivity of various materials within the chemical systems. The results of selected doping are included.

  17. Fabrication and characterization of CMOS-MEMS thermoelectric micro generators.

    PubMed

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

    2010-01-01

    This work presents a thermoelectric micro generator fabricated by the commercial 0.35 μm 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 μV at the temperature difference of 1 K. PMID:22205869

  18. Fabrication and Characterization of CMOS-MEMS Thermoelectric Micro Generators

    PubMed Central

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

    2010-01-01

    This work presents a thermoelectric micro generator fabricated by the commercial 0.35 μm 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 μV at the temperature difference of 1 K. PMID:22205869

  19. An oxide-based thermoelectric generator: Transversal thermoelectric strip-device

    NASA Astrophysics Data System (ADS)

    Teichert, S.; Bochmann, A.; Reimann, T.; Schulz, T.; Dreßler, C.; Töpfer, J.

    2015-07-01

    A special design of an oxide-based transversal thermoelectric device utilizing thermoelectric oxides in combination with a ceramic multilayer technology is proposed. Metal strips within the ceramic matrix replace the tilted stack of alternating layers used in artificial anisotropic transversal thermoelectric devices. Numerical three-dimensional simulations of both device types reveal better thermoelectric performance data for the device with metal stripes. A monolithic transversal strip-device based on the material combination La1.97Sr0.03CuO4/Ag6Pd1 was prepared and electrically characterized. A maximum power output of 4.0 mW was determined at ΔT = 225 K for the monolithic device. The observed results are in remarkable agreement with three-dimensional numerical simulations utilizing the transport parameters of the two materials and the geometry data of the device.

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

    PubMed

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

    2011-07-01

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

  1. Nonequilibrium Thermoelectrics: Low-Cost, High-Performance Materials for Cooling and Power Generation

    SciTech Connect

    Li, Q.

    2011-05-18

    Thermoelectric materials can be made into coolers (TECs) that use electricity to develop a temperature difference, cooling something, or generators (TEGs) that convert heat directly to electricity. One application of TEGs is to place them in a waste heat stream to recuperate some of the power being lost and putting it to use more profitably. To be effective thermoelectrics, however, materials must have both high electrical conductivity and low thermal conductivity, a combination rarely found in nature. Materials selection and processing has led to the development of several systems with a figure of merit, ZT, of nearly unity. By using non-equilibrium techniques, we have fabricated higher efficiency thermoelectric materials. The process involves creating an amorphous material through melt spinning and then sintering it with either spark plasma or a hot press for as little as two minutes. This results in a 100% dense material with an extremely fine grain structure. The grain boundaries appear to retard phonons resulting in a reduced thermal conductivity while the electrons move through the material relatively unchecked. The techniques used are low-cost and scaleable to support industrial manufacturing.

  2. Thermoelectric Generators for the Integration into Automotive Exhaust Systems for Passenger Cars and Commercial Vehicles

    NASA Astrophysics Data System (ADS)

    Frobenius, Fabian; Gaiser, Gerd; Rusche, Ulrich; Weller, Bernd

    2016-03-01

    A special thermoelectric generator system design and the setup of a thermoelectric generator for the integration into the exhaust line of combustion engine-driven vehicles are described. A prototype setup for passenger cars and the effects on the measured power output are shown. Measurement results using this setup show the potential and the limitations of a setup based on thermoelectric modules commercially available today. In a second step, a short outline of the detailed mathematical modeling of the thermoelectric generator and simulation studies based on this model are presented. By this means, it can be shown by which measures an improvement of the system power output can be achieved—even if today's modules are used. Furthermore, simulation studies show how the exhaust gas conditions of diesel- and Otto-engines significantly affect the requirements on thermoelectric materials as well as the potential and the design of the thermoelectric generator. In a further step, the design and the setup of a thermoelectric generator for an application in a commercial vehicle are presented. This thermoelectric generator is designed to be integrated into the exhaust aftertreatment box of the vehicle. Experimental results with this setup are performed and presented. The results show that thermoelectric generators can become an interesting technology for exhaust waste heat recovery due to the fact that they comprise non-moving parts. However, the efficiency of the modules commercially available today is still far from what is required. Hence, modules made of new materials known from laboratory samples are urgently required. With regard to future CO2 regulations, a large market opportunity for modules with a high efficiency can be expected.

  3. Search and Development of High Performance Thermoelectric Materials: A Controlled Approach

    NASA Technical Reports Server (NTRS)

    Fleurial, J. -P.

    1995-01-01

    The paper discusses some of the lessons learned in research and development of high performance thermoelectric materials. Discussion is on optimizing existing thermoelectric materials and considerations for development of new materials.

  4. Engineering Scoping Study of Thermoelectric Generator Systems for Industrial Waste Heat Recovery

    SciTech Connect

    Hendricks, Terry; Choate, William T.

    2006-11-01

    This report evaluates thermoelectric generator (TEG) systems with the intent to: 1) examine industrial processes in order to identify and quantify industrial waste heat sources that could potentially use TEGs; 2) describe the operating environment that a TEG would encounter in selected industrial processes and quantify the anticipated TEG system performance; 3) identify cost, design and/or engineering performance requirements that will be needed for TEGs to operate in the selected industrial processes; and 4) identify the research, development and deployment needed to overcome the limitations that discourage the development and use of TEGs for recovery of industrial waste heat.

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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.

  6. A high-output-voltage micro-thermoelectric generator having high-aspect-ratio structure

    NASA Astrophysics Data System (ADS)

    Kouma, N.; Nishino, T.; Tsuboi, O.

    2013-11-01

    A high-output-voltage micro-thermoelectric generator (µTEG) has been developed by fabricating thermocouples having a high aspect ratio (HAR) with a high integration density. They have been made by a novel and simple fabrication method, in which thermoelectric nanopowders are filled in a photosensitive glass mold by using aerosol deposition. It is followed by hot isostatic pressing to improve the thermoelectric property. This method has the possibility of increasing the aspect ratio of thermocouples drastically while increasing their toughness. We have fabricated thermocouples with an aspect ratio of 3.5 and a high integration density of 620 TCs cm-2. Their Seebeck coefficient and electrical resistivity are 290 µV K-1 and 1.5 mΩ cm, respectively, which make them as good as the thermocouples fabricated by hot pressing. By using the method, we have fabricated a µTEG chip having an area of 25 mm2 in which 56 thermocouples are arranged in an area of 9 mm2. The µTEG reaches a thermal resistance of 17.1 K W-1, output voltage efficiency of 0.16 V cm-2 K-1 and output power efficiency of 9.3 µW cm-2 K-2. These HAR thermocouples have an advantage for energy harvesting from a human body because they can result in a high temperature difference because of their high thermal resistance.

  7. Exploring packaging strategies of nano-embedded thermoelectric generators

    NASA Astrophysics Data System (ADS)

    Singha, Aniket; Mahanti, Subhendra D.; Muralidharan, Bhaskaran

    2015-10-01

    Embedding nanostructures within a bulk matrix is an important practical approach towards the electronic engineering of high performance thermoelectric systems. For power generation applications, it ideally combines the efficiency benefit offered by low dimensional systems along with the high power output advantage offered by bulk systems. In this work, we uncover a few crucial details about how to embed nanowires and nanoflakes in a bulk matrix so that an overall advantage over pure bulk may be achieved. First and foremost, we point out that a performance degradation with respect to bulk is inevitable as the nanostructure transitions to a multi moded one. It is then shown that a nano embedded system of suitable cross-section offers a power density advantage over a wide range of efficiencies at higher packing fractions, and this range gradually narrows down to the high efficiency regime, as the packing fraction is reduced. Finally, we introduce a metric - the advantage factor, to elucidate quantitatively, the enhancement in the power density offered via nano-embedding at a given efficiency. In the end, we explore the maximum effective width of nano-embedding which serves as a reference in designing generators in the efficiency range of interest.

  8. Long term behavior of silicon germanium thermoelectric generators

    NASA Technical Reports Server (NTRS)

    Shields, V.

    1981-01-01

    Results of tests of the long term performance of SiGe radioisotope thermoelectric generators (RTG) are presented. Three modules were monitored for 17,000-32,300 hr at hot junction temperatures of 1,085, 1,055, and 1,000 C; coating the unicouples with a 12,000 A thick layer of Si3N4 protected the modules from Si sublimation. Output degraded less than 0.3-0.4%/1,000 hr over the testing period. Life tests on a multihundredwatt (MHW) SiGe generator with 312 couples at a hot shoe temperature of 1,040 C dealt with power of 150 W at 30 V, with 0.5%/1,000 hr performance degradation. Si deposition on the insulation was found to enhance electrical conductance until a saturation point was reached. Disassembly of a test module after 16,750 hr revealed a Mo build-up, SiN4 coating deterioration, and Ti diffustion from the hot shoe to cooler regions of the junction. The presence of an Al2O3 insulator was recognized as preventing coating loss. Performance records from the Voyager and Les-8 satellites' RTG's are compared and show similar, 0.25%/1,000 hr degradation rates; RTG storage is judged to be feasible and the tests lead to projections of a 600,000 hr lifetime for a SiGe RTG.

  9. Exploring packaging strategies of nano-embedded thermoelectric generators

    SciTech Connect

    Singha, Aniket; Muralidharan, Bhaskaran; Mahanti, Subhendra D.

    2015-10-15

    Embedding nanostructures within a bulk matrix is an important practical approach towards the electronic engineering of high performance thermoelectric systems. For power generation applications, it ideally combines the efficiency benefit offered by low dimensional systems along with the high power output advantage offered by bulk systems. In this work, we uncover a few crucial details about how to embed nanowires and nanoflakes in a bulk matrix so that an overall advantage over pure bulk may be achieved. First and foremost, we point out that a performance degradation with respect to bulk is inevitable as the nanostructure transitions to a multi moded one. It is then shown that a nano embedded system of suitable cross-section offers a power density advantage over a wide range of efficiencies at higher packing fractions, and this range gradually narrows down to the high efficiency regime, as the packing fraction is reduced. Finally, we introduce a metric - the advantage factor, to elucidate quantitatively, the enhancement in the power density offered via nano-embedding at a given efficiency. In the end, we explore the maximum effective width of nano-embedding which serves as a reference in designing generators in the efficiency range of interest.

  10. Wearable thermoelectric generator for harvesting human body heat energy

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    SciTech Connect

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

    1989-01-01

    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

  12. Transitioning to Zero Freshwater Withdrawal for Thermoelectric Generation

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  13. Work plan for the fabrication of the radioisotope thermoelectric generator transportation system package mounting

    SciTech Connect

    Satoh, J.A.

    1994-11-09

    The Radioisotope Thermoelectric Generator (RTG) has available a dedicated system for the transportation of RTG payloads. The RTG Transportation System (System 100) is comprised of four systems; the Package (System 120), the Semi-trailer (System 140), the Gas Management (System 160), and the Facility Transport (System 180). This document provides guidelines on the fabrication, technical requirements, and quality assurance of the Package Mounting (Subsystem 145), part of System 140. The description follows the Development Control Requirements of WHC-CM-6-1, EP 2.4, Rev. 3.

  14. High-Performance Thermoelectric Semiconductors

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    Figures of merit almost double current state-of-art thermoelectric materials. IrSb3 is semiconductor found to exhibit exceptional thermoelectric properties. CoSb3 and RhSb3 have same skutterudite crystallographic structure as IrSb3, and exhibit exceptional transport properties expected to contribute to high thermoelectric performance. These three compounds form solid solutions. Combination of properties offers potential for development of new high-performance thermoelectric materials for more efficient thermoelectric power generators, coolers, and detectors.

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

    PubMed

    Yazawa, Kazuaki; Shakouri, Ali

    2011-09-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  17. Thermal vacuum life test facility for radioisotope thermoelectric generators

    SciTech Connect

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

    1990-01-01

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

  18. Thermal vacuum life test facility for radioisotope thermoelectric generators

    NASA Astrophysics Data System (ADS)

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

    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.

  19. Design of a polymer thermoelectric generator using radial architecture

    NASA Astrophysics Data System (ADS)

    Menon, Akanksha K.; Yee, Shannon K.

    2016-02-01

    Thermoelectric generators (TEGs) are solid-state heat engines consisting of p-type and n-type semiconductors that convert heat into electricity via the Seebeck effect. Conducting polymers are a viable alternative with intrinsic advantages over their inorganic counterparts, since they are abundant, flexible as thick-films, and have reduced manufacturing costs due to solution processing. Furthermore, polymers have an inherently low thermal conductivity, thus affording them the option of forgoing some heat exchanger costs. Current examples of polymer TE devices have been limited to traditional flat-plate geometries with power densities on the μW/cm2 scale, where their potential is not fully realized. Herein, we report a novel radial device architecture and model the improved performance of polymer-based TEG based on this architecture. Our radial architecture accommodates a fluid as the heat source and can operate under natural convection alone due to heat spreading. Analytical heat transfer and electrical models are presented that optimize the device for maximum power density, and for the first time we obtain the geometry matching condition that maximizes the efficiency. We predict high power densities of ˜1 mW/cm2 using state-of-the-art polymer TEs subjected to a temperature difference of 100 K, which is nearly 1000× higher than polymer flat-plate architectures reported in literature.

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

    PubMed

    Lertsatitthanakorn, C

    2007-05-01

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

  1. Truck co-generation system based on combustion heated thermoelectric conversion

    SciTech Connect

    Meleta, Ye.A.; Yarygin, V.I.; Klepikov, V.V.; Wolff, L.R.

    1997-12-31

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

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

    PubMed

    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

    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

  3. Residential Solar Combined Heat and Power Generation using Solar Thermoelectric Generation

    NASA Astrophysics Data System (ADS)

    Ohara, B.; Wagner, M.; Kunkle, C.; Watson, P.; Williams, R.; Donohoe, R.; Ugarte, K.; Wilmoth, R.; Chong, M. Zachary; Lee, H.

    2015-06-01

    Recent reports on improved efficiencies of solar thermoelectric generation (STEG) systems have generated interest in STEGs as a competitive power generation system. In this paper, the design of a combined cooling and power utilizing concentrated solar power is discussed. Solar radiation is concentrated into a receiver connected to thermoelectric modules, which are used as a topping cycle to generate power and high grade heat necessary to run an absorption chiller. Modeling of the overall system is discussed with experimental data to validate modeling results. A numerical modeling approach is presented which considers temperature variation of the source and sink temperatures and is used to maximize combined efficiency. A system is built with a demonstrated combined efficiency of 32% in actual working conditions with power generation of 3.1 W. Modeling results fell within 3% of the experimental results verifying the approach. An optimization study is performed on the mirror concentration ration and number of modules for thermal load matching and is shown to improve power generation to 26.8 W.

  4. Thermoelectric generators incorporating phase-change materials for waste heat recovery from engine exhaust

    SciTech Connect

    Meisner, Gregory P; Yang, Jihui

    2014-02-11

    Thermoelectric devices, intended for placement in the exhaust of a hydrocarbon fuelled combustion device and particularly suited for use in the exhaust gas stream of an internal combustion engine propelling a vehicle, are described. Exhaust gas passing through the device is in thermal communication with one side of a thermoelectric module while the other side of the thermoelectric module is in thermal communication with a lower temperature environment. The heat extracted from the exhaust gasses is converted to electrical energy by the thermoelectric module. The performance of the generator is enhanced by thermally coupling the hot and cold junctions of the thermoelectric modules to phase-change materials which transform at a temperature compatible with the preferred operating temperatures of the thermoelectric modules. In a second embodiment, a plurality of thermoelectric modules, each with a preferred operating temperature and each with a uniquely-matched phase-change material may be used to compensate for the progressive lowering of the exhaust gas temperature as it traverses the length of the exhaust pipe.

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

    NASA Astrophysics Data System (ADS)

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

    2002-01-01

    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.

  6. Evaluation of Thermoelectric Generators by I-V Curves

    NASA Astrophysics Data System (ADS)

    Min, Gao; Singh, Tanuj; Garcia-Canadas, Jorge; Ellor, Robert

    2016-03-01

    A recent theoretical study proposes a new way to evaluate thermoelectric devices by measuring two I-V curves—one obtained under a constant temperature difference and the other obtained for a constant thermal input. We report an experimental demonstration of the feasibility of this novel technique. A measurement system was designed and constructed, which enables both types of I-V curves to be obtained automatically. The effective ZT values of a thermoelectric module were determined using this system and compared with those measured by an impedance spectroscopy technique. The results confirm the validity of the proposed technique. In addition, the capability of measuring ZT under a large temperature difference was also investigated. The results show that the ZTs obtained for a large temperature difference are significantly smaller than those for a small temperature difference, providing insights into the design and operation of thermoelectric modules in realistic applications.

  7. Performance testing of thermoelectric generators including Voyager and LES 8/9 flight results

    NASA Technical Reports Server (NTRS)

    Garvey, L.; Stapfer, G.

    1979-01-01

    Several thermoelectric generators ranging in output power from 0.5 to 155 W have been completed or are undergoing testing at JPL. These generators represent a wide range of technologies, using Bi2Te3, PbTe and SiGe thermoelectric materials. Several of these generators are of a developmental type, such as HPG S/N2, and others are representative of Transit and Multi-Hundred Watt (MHW) Technology. Representative flight performance data of LES 8/9 and Voyager RTG's are presented and compared with the DEGRA computer program based on the data observed from tests of SiGe couples, modules and MHW generators.

  8. Fabrication of Miniature Thermoelectric Generators Using Bulk Materials

    NASA Astrophysics Data System (ADS)

    Joo, Sung-Jae; Ryu, Byungki; Min, Bok-Ki; Lee, Ji-Eun; Kim, Bong-Seo; Park, Su-Dong; Lee, Hee-Woong

    2016-05-01

    Miniature thermoelectric modules (TEMs) are required for micro power generation as well as local cooling, and they should have small size and high performance. However, conventional bulk TEMs generally have in-plane dimensions of a few centimeters, and empty space between the legs for electrical isolation makes efficient miniaturization difficult. In this study, a miniature TEM with footprint of about 0.35 cm2 and leg height of 0.97 mm was fabricated by reducing the dimensions of the legs and attaching them together to form a closely packed assembly, without using microelectromechanical processes. First, Bi0.4Sb1.6Te3 (BST) and Bi2Te2.7Se0.3 (BTS) ingots were made by ball milling and spark plasma sintering, and the ingots were cut into thin plates. These BST and BTS plates were then attached alternately using polyimide tapes, and the attached plates were sliced vertically to produce thin sheets. This process was repeated once again to make chessboard-like assemblies having 20 p-n pairs in an area of 0.35 cm2, and electrical contacts were formed by Ni sputtering and Ag paste coating. Finally, thermally conductive silicone pads (~500 μm) were attached on both sides of the assembly using electrically insulating interface thermal tapes (˜180 μm). The maximum output power (P max) from the miniature module was about 28 μW and 2.0 mW for temperature difference (ΔT) of 5.6°C and 50.5°C, respectively. Reducing the contact resistance was considered to be the key to increase the output power.

  9. Fabrication of Miniature Thermoelectric Generators Using Bulk Materials

    NASA Astrophysics Data System (ADS)

    Joo, Sung-Jae; Ryu, Byungki; Min, Bok-Ki; Lee, Ji-Eun; Kim, Bong-Seo; Park, Su-Dong; Lee, Hee-Woong

    2016-07-01

    Miniature thermoelectric modules (TEMs) are required for micro power generation as well as local cooling, and they should have small size and high performance. However, conventional bulk TEMs generally have in-plane dimensions of a few centimeters, and empty space between the legs for electrical isolation makes efficient miniaturization difficult. In this study, a miniature TEM with footprint of about 0.35 cm2 and leg height of 0.97 mm was fabricated by reducing the dimensions of the legs and attaching them together to form a closely packed assembly, without using microelectromechanical processes. First, Bi0.4Sb1.6Te3 (BST) and Bi2Te2.7Se0.3 (BTS) ingots were made by ball milling and spark plasma sintering, and the ingots were cut into thin plates. These BST and BTS plates were then attached alternately using polyimide tapes, and the attached plates were sliced vertically to produce thin sheets. This process was repeated once again to make chessboard-like assemblies having 20 p- n pairs in an area of 0.35 cm2, and electrical contacts were formed by Ni sputtering and Ag paste coating. Finally, thermally conductive silicone pads (~500 μm) were attached on both sides of the assembly using electrically insulating interface thermal tapes (˜180 μm). The maximum output power ( P max) from the miniature module was about 28 μW and 2.0 mW for temperature difference (Δ T) of 5.6°C and 50.5°C, respectively. Reducing the contact resistance was considered to be the key to increase the output power.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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.

  11. Skutterudite Thermoelectric Generator for Electrical Power Generation from Automotive Waste Heat

    NASA Astrophysics Data System (ADS)

    Meisner, Gregory

    2012-02-01

    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^2σT/κ (S = Seebeck coefficient, σ = electrical conductivity, T = temperature, and κ = 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.

  12. Maximum Power Point Tracking with Dichotomy and Gradient Method for Automobile Exhaust Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    Fang, W.; Quan, S. H.; Xie, C. J.; Tang, X. F.; Wang, L. L.; Huang, L.

    2016-03-01

    In this study, a direct-current/direct-current (DC/DC) converter with maximum power point tracking (MPPT) is developed to down-convert the high voltage DC output from a thermoelectric generator to the lower voltage required to charge batteries. To improve the tracking accuracy and speed of the converter, a novel MPPT control scheme characterized by an aggregated dichotomy and gradient (ADG) method is proposed. In the first stage, the dichotomy algorithm is used as a fast search method to find the approximate region of the maximum power point. The gradient method is then applied for rapid and accurate tracking of the maximum power point. To validate the proposed MPPT method, a test bench composed of an automobile exhaust thermoelectric generator was constructed for harvesting the automotive exhaust heat energy. Steady-state and transient tracking experiments under five different load conditions were carried out using a DC/DC converter with the proposed ADG and with three traditional methods. The experimental results show that the ADG method can track the maximum power within 140 ms with a 1.1% error rate when the engine operates at 3300 rpm@71 NM, which is superior to the performance of the single dichotomy method, the single gradient method and the perturbation and observation method from the viewpoint of improved tracking accuracy and speed.

  13. Unileg Thermoelectric Generator Design for Oxide Thermoelectrics and Generalization of the Unileg Design Using an Idealized Metal

    NASA Astrophysics Data System (ADS)

    Wijesekara, Waruna; Rosendahl, Lasse; Brown, David R.; Snyder, G. Jeffrey

    2015-06-01

    The unileg thermoelectric generator (U-TEG) is an increasingly popular concept in the design of thermoelectric generators (TEGs). In this study, an oxide U-TEG design for high-temperature applications is introduced. For the unicouple TEG design, Ca3Co4O9 and Al-doped ZnO are used as the p- and n-leg thermoelectric materials, respectively. For the U-TEG design, constantan and Ca3Co4O9 are employed as conductor and semiconductor, respectively. The reduced current approach (RCA) technique is used to design the unicouple TEG and U-TEG in order to obtain the optimal area ratio. When both the unicouple TEG and U-TEG were subjected to a heat flux of 20 W/cm2, the volumetric power density was 0.18 W/cm3 and 0.44 W/cm3, respectively. Thermal shorting between the hot and cold sides of the generator through the highly thermally conducting conductor, which is one of the major drawbacks of the U-TEG, is overcome by using the optimal area ratio for conductor and semiconductor given by the RCA. The results are further confirmed by finite-element analysis using COMSOL Multiphysics software. Furthermore, the U-TEG design is generalized by using an idealized metal with zero Seebeck coefficient. Even though the idealized metal has no impact on the power output of the U-TEG and all the power in the system is generated by the semiconductor, the U-TEG design succeeded in producing a higher volumetric power density than the unicouple TEG design.

  14. Analysis of an Increase in the Efficiency of a Spark Ignition Engine Through the Application of an Automotive Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Merkisz, Jerzy; Fuc, Pawel; Lijewski, Piotr; Ziolkowski, Andrzej; Galant, Marta; Siedlecki, Maciej

    2016-05-01

    We have analyzed the increase of the overall efficiency of a spark ignition engine through energy recovery following the application of an automotive thermoelectric generator (ATEG) of our own design. The design of the generator was developed following emission investigations during vehicle driving under city traffic conditions. The measurement points were defined by actual operation conditions (engine speed and load), subsequently reproduced on an engine dynamometer. Both the vehicle used in the on-road tests and the engine dynamometer were fit with the same, downsized spark ignition engine (with high effective power-to-displacement ratio). The thermodynamic parameters of the exhaust gases (temperature and exhaust gas mass flow) were measured on the engine testbed, along with the fuel consumption and electric current generated by the thermoelectric modules. On this basis, the power of the ATEG and its impact on overall engine efficiency were determined.

  15. Analysis of an Increase in the Efficiency of a Spark Ignition Engine Through the Application of an Automotive Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Merkisz, Jerzy; Fuc, Pawel; Lijewski, Piotr; Ziolkowski, Andrzej; Galant, Marta; Siedlecki, Maciej

    2016-08-01

    We have analyzed the increase of the overall efficiency of a spark ignition engine through energy recovery following the application of an automotive thermoelectric generator (ATEG) of our own design. The design of the generator was developed following emission investigations during vehicle driving under city traffic conditions. The measurement points were defined by actual operation conditions (engine speed and load), subsequently reproduced on an engine dynamometer. Both the vehicle used in the on-road tests and the engine dynamometer were fit with the same, downsized spark ignition engine (with high effective power-to-displacement ratio). The thermodynamic parameters of the exhaust gases (temperature and exhaust gas mass flow) were measured on the engine testbed, along with the fuel consumption and electric current generated by the thermoelectric modules. On this basis, the power of the ATEG and its impact on overall engine efficiency were determined.

  16. Special Applications RTG Technology Program: Thermoelectric module development summary report

    SciTech Connect

    Brittain, W.M.

    1988-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

    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.

  18. Close-packed-array (CPA) thermoelectric module development status

    SciTech Connect

    Brittain, W.M. )

    1991-01-05

    Prior effort on the U.S. Department of Energy-sponsored Special Applications Radioisotope Thermoelectric Generator (RTG) Technology Program and Two-Watt RTG Program has focused on terrestrial applications where the RTG will be exposed to relatively low temperature thermal environments (subsea). Thus, effort has been oriented towards design optimization at cold junction temperatures in the 10 to 93 {degree}C (50 to 200 {degree}F) range. However, for other more severe design environments (such as space applications where a high heat rejection radiator temperature in the 177 to 204 {degree}C (350 to 400 {degree}F) range is required to minimize RTG size and weight, and high g shock/vibration capability is necessary) a modified thermoelectric module design is dictated. In order to minimize the RTG system size and weight, and to increase the mechanical strength of the thermoelectric module to withstand increased dynamic loads, a close-packed-array (CPA) module configuration is desirable. The monolithic nature of such a module generally results in greater shear and compression load capability than free-standing individual couples. A CPA module is especially attractive for terrestrial and space applications where severe structural loads will be imposed such as airborne deployment or planetary landers and penetrators.

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

    NASA Astrophysics Data System (ADS)

    Bosch, Henry

    2016-03-01

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

  20. Close-packed-array (CPA) thermoelectric module development status

    NASA Astrophysics Data System (ADS)

    Brittain, Wayne M.

    1991-01-01

    Prior effort on the U.S. Department of Energy-sponsored Special Applications Radioisotope Thermoelectric Generator (RTG) Technology Program and Two-Watt RTG Program has focused on terrestrial applications where the RTG will be exposed to relatively low temperature thermal environments (subsea). Thus, effort has been oriented towards design optimization at cold junction temperatures in the 10 to 93 °C (50 to 200 °F) range. However, for other more severe design environments (such as space applications where a high heat rejection radiator temperature in the 177 to 204 °C (350 to 400 °F) range is required to minimize RTG size and weight, and high g shock/vibration capability is necessary) a modified thermoelectric module design is dictated. In order to minimize the RTG system size and weight, and to increase the mechanical strength of the thermoelectric module to withstand increased dynamic loads, a close-packed-array (CPA) module configuration is desirable. The monolithic nature of such a module generally results in greater shear and compression load capability than free-standing individual couples. A CPA module is especially attractive for terrestrial and space applications where severe structural loads will be imposed such as airborne deployment or planetary landers and penetrators. An additional benefit of the CPA module is the potential for obtaining higher output voltage and increased circuit redundancy. The CPA module construction will permit fabrication and installation of smaller cross section thermoelectric minicouples due to the enhanced structural configuration. This is an important factor for small size, low power, high voltage terrestrial and space RTSs as well as modularity considerations in higher power space RTGs where circuit redundancy as well as high voltage are desirable.

  1. Power-Generation Performance and Durability of a Skutterudite Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  2. Development of Thick-Film Thermoelectric Microcoolers Using Electrochemical Deposition

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  3. A Digital Coreless Maximum Power Point Tracking Circuit for Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Suemori, Kouji; Hoshino, Satoshi; Kamata, Toshihide

    2013-10-01

    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.

  5. Thermoelectricity Generation and Electron-Magnon Scattering in a Natural Chalcopyrite Mineral from a Deep-Sea Hydrothermal Vent.

    PubMed

    Ang, Ran; Khan, Atta Ullah; Tsujii, Naohito; Takai, Ken; Nakamura, Ryuhei; Mori, Takao

    2015-10-26

    Current high-performance thermoelectric materials require elaborate doping and synthesis procedures, particularly in regard to the artificial structure, and the underlying thermoelectric mechanisms are still poorly understood. Here, we report that a natural chalcopyrite mineral, Cu1+x Fe1-x S2 , obtained from a deep-sea hydrothermal vent can directly generate thermoelectricity. The resistivity displayed an excellent semiconducting character, and a large thermoelectric power and high power factor were found in the low x region. Notably, electron-magnon scattering and a large effective mass was detected in this region, thus suggesting that the strong coupling of doped carriers and antiferromagnetic spins resulted in the natural enhancement of thermoelectric properties during mineralization reactions. The present findings demonstrate the feasibility of thermoelectric energy generation and electron/hole carrier modulation with natural materials that are abundant in the Earth's crust. PMID:26332260

  6. Exhaust gas bypass valve control for thermoelectric generator

    SciTech Connect

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

    2012-09-04

    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.

  7. Structurally complex Zintl compounds for high temperature thermoelectric power generation

    NASA Astrophysics Data System (ADS)

    Zevalkink, Alexandra; Pomrehn, Gregory; Gibbs, Zachary; Snyder, Jeffrey

    2014-03-01

    Zintl phases, characterized by covalently-bonded substructures surrounded by highly electropositive cations, exhibit many of the characteristics desired for thermoelectric applications. Recently, we demonstrated promising thermoelectric performance (zT values between 0.4 and 0.9) in a class of Zintl antimonides that share a common structural motif: anionic moieties resembling infinite chains of linked tetrahedra. These compounds (A5M2 Sb6 and A3 M Sb3 compounds where A = Ca or Sr and M = Al, Ga and In) crystallize as four distinct, but closely related chain-forming structure types. Their large unit cells lead to exceptionally low lattice thermal conductivity due to the containment of heat in low velocity optical phonon modes. Here, we show that chemical substitutions on the A and M sites can be used to control the electronic and thermal transport properties and optimize the thermoelectric figure of merit. Doping with alio-valent elements allows for rational control of the carrier concentration, while isoelectronic substitutions can be used to fine-tune the intrinsic properties. A combination of Density Functional calculations and classical transport models was used to explain the experimentally observed transport properties of these compounds.

  8. Model of Heat Exchangers for Waste Heat Recovery from Diesel Engine Exhaust for Thermoelectric Power Generation

    NASA Astrophysics Data System (ADS)

    Baker, Chad; Vuppuluri, Prem; Shi, Li; Hall, Matthew

    2012-06-01

    The performance and operating characteristics of a hypothetical thermoelectric generator system designed to extract waste heat from the exhaust of a medium-duty turbocharged diesel engine were modeled. The finite-difference model consisted of two integrated submodels: a heat exchanger model and a thermoelectric device model. The heat exchanger model specified a rectangular cross-sectional geometry with liquid coolant on the cold side, and accounted for the difference between the heat transfer rate from the exhaust and that to the coolant. With the spatial variation of the thermoelectric properties accounted for, the thermoelectric device model calculated the hot-side and cold-side heat flux for the temperature boundary conditions given for the thermoelectric elements, iterating until temperature and heat flux boundary conditions satisfied the convection conditions for both exhaust and coolant, and heat transfer in the thermoelectric device. A downhill simplex method was used to optimize the parameters that affected the electrical power output, including the thermoelectric leg height, thermoelectric n-type to p-type leg area ratio, thermoelectric leg area to void area ratio, load electrical resistance, exhaust duct height, coolant duct height, fin spacing in the exhaust duct, location in the engine exhaust system, and number of flow paths within the constrained package volume. The calculation results showed that the configuration with 32 straight fins was optimal across the 30-cm-wide duct for the case of a single duct with total height of 5.5 cm. In addition, three counterflow parallel ducts or flow paths were found to be an optimum number for the given size constraint of 5.5 cm total height, and parallel ducts with counterflow were a better configuration than serpentine flow. Based on the reported thermoelectric properties of MnSi1.75 and Mg2Si0.5Sn0.5, the maximum net electrical power achieved for the three parallel flow paths in a counterflow arrangement was 1

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

    SciTech Connect

    Kiebel, G.R.

    1991-09-01

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

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

    SciTech Connect

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

    1996-03-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    SciTech Connect

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

    1991-06-01

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

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

    SciTech Connect

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

    1991-09-01

    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.

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

    PubMed

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

    2013-10-01

    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

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

    PubMed Central

    2013-01-01

    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. PMID:23937226

  16. Thermoelectrics: Carbon nanotubes get high

    NASA Astrophysics Data System (ADS)

    Crispin, Xavier

    2016-04-01

    Waste heat can be converted to electricity by thermoelectric generators, but their development is hindered by the lack of cheap materials with good thermoelectric properties. Now, carbon-nanotube-based materials are shown to have improved properties when purified to contain only semiconducting species and then doped.

  17. Vaporization and compatibility of SiGe radioisotope thermoelectric generators.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  18. Experimental Investigation of a Temperature-Controlled Car Seat Powered by an Exhaust Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Du, H.; Wang, Y. P.; Yuan, X. H.; Deng, Y. D.; Su, C. Q.

    2016-03-01

    To improve the riding comfort and rational utilization of the electrical energy captured by an automotive thermoelectric generator (ATEG), a temperature-controlled car seat was constructed to adjust the temperature of the car seat surface. Powered by the ATEG and the battery, the seat-embedded air conditioner can improve the riding comfort using a thermoelectric device to adjust the surface temperature of the seat, with an air duct to regulate the cold side and hot side of the thermoelectric device. The performance of the thermoelectric cooler (TEC) and theoretical analysis on the optimum state of the TEC device are put forward. To verify the rationality of the air duct design and to ensure sufficient air supply, the velocity field of the air duct system was obtained by means of the finite element method. To validate the reliability of the numerical simulation, the air velocity around the thermoelectric device was measured by a wind speed transmitter. The performance of the temperature-controlled car seat has been validated and is in good agreement with bench tests and real vehicle tests.

  19. Hybrid Thermoelectric-Photovoltaic Generators in Wireless Electroencephalography Diadem and Electrocardiography Shirt

    NASA Astrophysics Data System (ADS)

    Leonov, Vladimir; Torfs, Tom; Vullers, Ruud J. M.; van Hoof, Chris

    2010-09-01

    Hybrid wearable energy harvesters consisting of a thermoelectric generator (TEG) and photovoltaic (PV) cells are used in this work for powering two autonomous medical devices: an electroencephalography (EEG) system and an electrocardiography (ECG) system in a shirt. Two alternative solutions for powering the systems have been implemented. In the battery-free EEG diadem, PV cells cover the outer surface of radiators used in a TEG. In the ECG shirt, thermoelectric modules are the main power supply that constantly recharges a battery, while PV cells are used mainly to provide standby power, i.e., when the shirt is not worn. Both devices are maintenance free for their entire service life.

  20. Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part II: Parametric Evaluation and Topological Studies

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    A comprehensive numerical model has been proposed to model thermoelectric generators (TEGs) for automotive waste heat recovery. Details of the model and results from the analysis of General Motors' prototype TEG were described in part I of the study. In part II of this study, parametric evaluations are considered to assess the influence of heat exchanger, geometry, and thermoelectric module configurations to achieve optimization of the baseline model. The computational tool is also adapted to model other topologies such as transverse and circular configurations (hexagonal and cylindrical) maintaining the same volume as the baseline TEG. Performance analysis of these different topologies and parameters is presented and compared with the baseline design.

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

    SciTech Connect

    1996-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Chimchavee, W.

    2011-05-01

    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

  3. Hardware Implementation of Maximum Power Point Tracking for Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  4. High-power thermoelectric generators based on nanostructured silicon

    NASA Astrophysics Data System (ADS)

    Pennelli, G.; Macucci, M.

    2016-05-01

    The low thermal conductivity of silicon nanowires and nanostructures opens interesting opportunities for energy harvesting through the direct, high-efficiency, conversion of waste heat into electrical power. We present solutions for the fabrication and interconnection of a high number of suspended silicon nanostructures, within CMOS compatible top-down processes. Mechanical stability and thermoelectric properties of these devices will be analysed by means of finite element simulations, and opportunities for practical applications will be discussed. It will be shown that, despite the reduced dimensions needed for a strong suppression of thermal conductivity, a considerable amount of electrical power can be delivered to the load as a result of the presence of many interconnected devices on the same chip.

  5. Thermoelectric Power Generation Utilizing the Waste Heat from a Biomass Boiler

    NASA Astrophysics Data System (ADS)

    Brazdil, Marian; Pospisil, Jiri

    2013-07-01

    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.

  6. Studies on Effective Utilization of SOFC Exhaust Heat Using Thermoelectric Power Generation Technology

    NASA Astrophysics Data System (ADS)

    Terayama, Takeshi; Nagata, Susumu; Tanaka, Yohei; Momma, Akihiko; Kato, Tohru; Kunii, Masaru; Yamamoto, Atsushi

    2013-07-01

    Solid oxide fuel cells (SOFCs) are being researched around the world. In Japan, a compact SOFC system with rated alternative current (AC) power of 700 W has become available on the market, since the base load electricity demand for a standard home is said to be less than 700 W AC. To improve the generating efficiency of SOFC systems in the 700-W class, we focused on thermoelectric generation (TEG) technology, since there are a lot of temperature gradients in the system. Analysis based on simulations indicated the possibility of introducing thermoelectric generation at the air preheater, steam generator, and exhaust outlet. Among these options, incorporating a TEG heat exchanger comprising multiple CoSb3/SiGe-based TEG modules into the air preheater had potential to produce additional output of 37.5 W and an improvement in generating efficiency from 46% to 48.5%. Furthermore, by introducing thermoelectric generation at the other two locations, an increase in maximum output of more than 50 W and generating efficiency of 50% can be anticipated.

  7. Modeling of a Thermoelectric Generator for Thermal Energy Regeneration in Automobiles

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  8. Development of a Platform for Simulating and Optimizing Thermoelectric Energy Systems

    NASA Astrophysics Data System (ADS)

    Kreuder, John J.

    Thermoelectrics are solid state devices that can convert thermal energy directly into electrical energy. They have historically been used only in niche applications because of their relatively low efficiencies. With the advent of nanotechnology and improved manufacturing processes thermoelectric materials have become less costly and more efficient As next generation thermoelectric materials become available there is a need for industries to quickly and cost effectively seek out feasible applications for thermoelectric heat recovery platforms. Determining the technical and economic feasibility of such systems requires a model that predicts performance at the system level. Current models focus on specific system applications or neglect the rest of the system altogether, focusing on only module design and not an entire energy system. To assist in screening and optimizing entire energy systems using thermoelectrics, a novel software tool, Thermoelectric Power System Simulator (TEPSS), is developed for system level simulation and optimization of heat recovery systems. The platform is designed for use with a generic energy system so that most types of thermoelectric heat recovery applications can be modeled. TEPSS is based on object-oriented programming in MATLABRTM. A modular, shell based architecture is developed to carry out concept generation, system simulation and optimization. Systems are defined according to the components and interconnectivity specified by the user. An iterative solution process based on Newton's Method is employed to determine the system's steady state so that an objective function representing the cost of the system can be evaluated at the operating point. An optimization algorithm from MATLAB's Optimization Toolbox uses sequential quadratic programming to minimize this objective function with respect to a set of user specified design variables and constraints. During this iterative process many independent system simulations are executed and

  9. Development of n-type cobaltocene-encapsulated carbon nanotubes with remarkable thermoelectric property

    PubMed Central

    Fukumaru, Takahiro; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2015-01-01

    Direct conversion from heat to electricity is one of the important technologies for a sustainable society since large quantities of energy are wasted as heat. We report the development of a single-walled carbon nanotube (SWNT)-based high conversion efficiency, air-stable and flexible thermoelectric material. We prepared cobaltocene-encapsulated SWNTs (denoted CoCp2@SWNTs) and revealed that the material showed a negative-type (n-type) semiconducting behaviour (Seebeck coefficient: −41.8 μV K−1 at 320 K). The CoCp2@SWNT film was found to show a high electrical conductivity (43,200 S m−1 at 320 K) and large power factor (75.4 μW m−1 K−2) and the performance was remarkably stable under atmospheric conditions over a wide range of temperatures. The thermoelectric figure of merit (ZT) value of the CoCp2@SWNT film (0.157 at 320 K) was highest among the reported n-type organic thermoelectric materials due to the large power factor and low thermal conductivity (0.15 W m−1 K−1). These characteristics of the n-type CoCp2@SWNTs allowed us to fabricate a p-n type thermoelectric device by combination with an empty SWNT-based p-type film. The fabricated device exhibited a highly efficient power generation close to the calculated values even without any air-protective coating due to the high stability of the SWNT-based materials under atmospheric conditions. PMID:25608478

  10. Development of CCD Imaging System Using Thermoelectric Cooling Method

    NASA Astrophysics Data System (ADS)

    Park, Youngsik; Lee, Ho Jin; Han, Wonyong; Nam, Uk-Won; Lee, Yong-Sam

    2000-06-01

    We developed low light CCD imaging system using thermoelectric cooling method collaboration with a company to design a commercial model. It consists of Kodak KAF-0401E (768x512 pixels) CCD chip,thermoelectric module manufactured by Thermotek. This TEC system can reach an operative temperature of -25deg. We employed an Uniblitz VS25S shutter and it has capability a minimum exposure time 80ms. The system components are an interface card using a Korea Astronomy Observatory (hereafter KAO) ISA bus controller, image acquisition with AD9816 chip, that is 12bit video processor. The performance test with this imaging system showed good operation within the initial specification of our design. It shows a dark current less than 0.4e-/pixel/sec at a temperature of -10deg, a linearity 99.9+/-0.1%, gain 4.24e-adu, and system noise is 25.3e- (rms). For low temperature CCD operation, we designed a TEC, which uses a one-stage peltier module and forced air heat exchanger. This TEC imaging system enables accurate photometry (+/-0.01mag) even though the CCD is not at 'conventional' cryogenic temperatures (140K). The system can be a useful instrument for any other imaging applications. Finally, with this system, we obtained several images of astronomical objects for system performance tests.

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

    SciTech Connect

    Van Harlingen, D. J.

    1981-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

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

    SciTech Connect

    Trivedi, Sudhir B.; Kutcher, Susan W.; Rosemeier, Cory A.; Mayers, David; Singh, Jogender

    2013-12-02

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

  14. Complex oxides useful for thermoelectric energy conversion

    SciTech Connect

    Majumdar, Arunava; Ramesh, Ramamoorthy; Yu, Choongho; Scullin, Matthew L.; Huijben, Mark

    2012-07-17

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

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

    SciTech Connect

    David Feldman; Amanda Slough; Gary Garrett

    2008-06-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

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

    SciTech Connect

    Becker, D.L.

    1997-05-01

    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.

  18. Computational Analysis of a Thermoelectric Generator for Waste-Heat Harvesting in Wearable Systems

    NASA Astrophysics Data System (ADS)

    Kossyvakis, D. N.; Vassiliadis, S. G.; Vossou, C. G.; Mangiorou, E. E.; Potirakis, S. M.; Hristoforou, E. V.

    2016-03-01

    Over recent decades, a constantly growing interest in the field of portable electronic devices has been observed. Recent developments in the scientific areas of integrated circuits and sensing technologies have enabled realization and design of lightweight low-power wearable sensing systems that can be of great use, especially for continuous health monitoring and performance recording applications. However, to facilitate wide penetration of such systems into the market, the issue of ensuring their seamless and reliable power supply still remains a major concern. In this work, the performance of a thermoelectric generator, able to exploit the temperature difference established between the human body and the environment, has been examined computationally using ANSYS 14.0 finite-element modeling (FEM) software, as a means for providing the necessary power to various portable electronic systems. The performance variation imposed due to different thermoelement geometries has been estimated to identify the most appropriate solution for the considered application. Furthermore, different ambient temperature and heat exchange conditions between the cold side of the generator and the environment have been investigated. The computational analysis indicated that power output in the order of 1.8 mW can be obtained by a 100-cm2 system, if specific design criteria can be fulfilled.

  19. Thermoelectric thin film power generators: self-sustaining power supply for smart systems

    NASA Astrophysics Data System (ADS)

    Nurnus, Joachim

    2009-05-01

    Micropelt develops and markets the world's smallest thermoelectric power generation devices. Due to the silicon-wafer based MEMS-like production process elements with a total thickness of 1 mm and a footprint from less than 1 mm² to 25 mm2 can be realized. The fabrication process is based on standard semiconductor equipment and processes. Therefore ramp-up schemes and economies-of-scale close to those of common chip devices apply to Micropelt products. Micropelt thermogenerators produce much higher output voltages than conventional bulk devices which is due to the fact that their micro-structuring technology produces near 8000 p-n thermo-couples per square centimeter, while conventional thermogenerators typically have less than 10 such thermo-couples on the same area. Consequently Micropelt generators are well suited as the core of an integrated power supply for energy-autonomous miniaturized smart systems with average power consumptions of a few Milliwatts. Micropelt Engineering has proven readiness of their devices for use in a multitude of wireless sensor and micro systems, including smart actuators In this paper we will first introduce the Micropelt technology and further discuss energy harvesting opportunities for novel low power devices and wireless applications based on given waste heat reservoirs.

  20. Computational Analysis of a Thermoelectric Generator for Waste-Heat Harvesting in Wearable Systems

    NASA Astrophysics Data System (ADS)

    Kossyvakis, D. N.; Vassiliadis, S. G.; Vossou, C. G.; Mangiorou, E. E.; Potirakis, S. M.; Hristoforou, E. V.

    2016-06-01

    Over recent decades, a constantly growing interest in the field of portable electronic devices has been observed. Recent developments in the scientific areas of integrated circuits and sensing technologies have enabled realization and design of lightweight low-power wearable sensing systems that can be of great use, especially for continuous health monitoring and performance recording applications. However, to facilitate wide penetration of such systems into the market, the issue of ensuring their seamless and reliable power supply still remains a major concern. In this work, the performance of a thermoelectric generator, able to exploit the temperature difference established between the human body and the environment, has been examined computationally using ANSYS 14.0 finite-element modeling (FEM) software, as a means for providing the necessary power to various portable electronic systems. The performance variation imposed due to different thermoelement geometries has been estimated to identify the most appropriate solution for the considered application. Furthermore, different ambient temperature and heat exchange conditions between the cold side of the generator and the environment have been investigated. The computational analysis indicated that power output in the order of 1.8 mW can be obtained by a 100-cm2 system, if specific design criteria can be fulfilled.

  1. Microcombustor-thermoelectric power generator for 10-50 watt applications

    NASA Astrophysics Data System (ADS)

    Marshall, Daniel S.; Cho, Steve T.

    2010-04-01

    Fuel-based portable power systems, including combustion and fuel cell systems, take advantage of the 80x higher energy density of fuel over lithium battery technologies and offer the potential for much higher energy density power sources - especially for long-duration applications, such as unattended sensors. Miniaturization of fuel-based systems poses significant challenges, including processing of fuel in small channels, catalyst poisoning, and coke and soot formation. Recent advances in micro-miniature combustors in the 200Watt thermal range have enabled the development of small power sources that use the chemical energy of heavy fuel to drive thermal-to-electric converters for portable applications. CUBE Technology has developed compact Micro-Furnace combustors that efficiently deliver high-quality heat to optimized thermal-to-electric power converters, such as advanced thermoelectric power modules and Stirling motors, for portable power generation at the 10-50Watt scale. Key innovations include a compact gas-gas recuperator, innovative heavy fuel processing, coke- & soot-free operation, and combustor optimization for low balance-of-plant power use while operating at full throttle. This combustor enables the development of robust, high energy density, miniature power sources for portable applications.

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  3. Influence of thermal environment on optimal working conditions of thermoelectric generators

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    SciTech Connect

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

    2010-09-01

    The U.S. military uses large amounts of fuel during deployments and battlefield operations. This project sought to develop a lightweight, small form-factor, soldier-portable advanced thermoelectric (TE) system prototype to recover and convert waste heat from various deployed military equipment (i.e., diesel generators/engines, incinerators, vehicles, and potentially mobile kitchens), with the ultimate purpose of producing power for soldier battery charging, advanced capacitor charging, and other battlefield power applications. The technical approach employed microchannel technology, a unique “power panel” approach to heat exchange/TE system integration, and newly-characterized LAST (lead-antimony-silver-telluride) and LASTT (lead-antimony-silver-tin-telluride) TE materials segmented with bismuth telluride TE materials in 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.

  5. Thermoelectric Devices Cool, Power Electronics

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Nextreme Thermal Solutions Inc., based in Research Triangle Park, North Carolina, licensed thermoelectric technology from NASA s Jet Propulsion Laboratory. This has allowed the company to develop cutting edge, thin-film thermoelectric coolers that effective remove heat generated by increasingly powerful and tightly packed microchip components. These solid-state coolers are ideal solutions for applications like microprocessors, laser diodes, LEDs, and even potentially for cooling the human body. Nextreme s NASA technology has also enabled the invention of thermoelectric generators capable of powering technologies like medical implants and wireless sensor networks.

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

    NASA Astrophysics Data System (ADS)

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

    1983-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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

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

    SciTech Connect

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

    1981-09-01

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

  12. A Comprehensive 3D Finite Element Model of a Thermoelectric Module Used in a Power Generator: A Transient Performance Perspective

    NASA Astrophysics Data System (ADS)

    Wu, Guangxi; Yu, Xiong

    2015-06-01

    Thermoelectric power generator has potential for small-scale and distributed power generation because of its high durability and scalability. It is very important to realize that the transient behavior of thermoelectric modules (TEM) affects a thermoelectric generator's response to dynamic working environments. Traditionally, researchers have used simplified models to describe the behavior of thermoelectric modules. In this paper we propose a comprehensive mathematical model that considers the effect of variations of chemical potential and carrier density, which are ignored by traditional models. Finite element models based on this new model are used to simulate the transient behavior of a thermoelectric module subjected to rapid changes in boundary temperature or working load. Simulation results show that transition times of thermoelectric modules affected by temperature change are much longer than those of modules affected by changes in electrical load resistance. Sudden changes in working temperature cause voltage overshoot of the TEM output, which, however, is not observed in responses to sudden changes of load resistance. Comparisons also show there are significant differences between the behavior of TEM predicted by use of this new comprehensive model and that predicted by use of traditional models, particularly for the high-temperature intrinsic ionization region and the low-temperature weak ionization region. This implies that chemical potential and carrier density variations, which are taken into account by this new model but ignored by traditional models, have major effects on the performance of TEM.

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

    PubMed

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

    2007-09-01

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

  14. Development of a System for Thermoelectric Heat Recovery from Stationary Industrial Processes

    NASA Astrophysics Data System (ADS)

    Ebling, D. G.; Krumm, A.; Pfeiffelmann, B.; Gottschald, J.; Bruchmann, J.; Benim, A. C.; Adam, M.; Labs, R.; Herbertz, R. R.; Stunz, A.

    2016-05-01

    The hot forming process of steel requires temperatures of up to 1300°C. Usually, the invested energy is lost to the environment by the subsequent cooling of the forged parts to room temperature. Thermoelectric systems are able to recover this wasted heat by converting the heat into electrical energy and feeding it into the power grid. The proposed thermoelectric system covers an absorption surface of half a square meter, and it is equipped with 50 Bismuth-Telluride based thermoelectric generators, five cold plates, and five inverters. Measurements were performed under production conditions of the industrial environment of the forging process. The heat distribution and temperature profiles are measured and modeled based on the prevailing production conditions and geometric boundary conditions. Under quasi-stationary conditions, the thermoelectric system absorbs a heat radiation of 14.8 kW and feeds electrical power of 388 W into the power grid. The discussed model predicts the measured values with slight deviations.

  15. Development of a System for Thermoelectric Heat Recovery from Stationary Industrial Processes

    NASA Astrophysics Data System (ADS)

    Ebling, D. G.; Krumm, A.; Pfeiffelmann, B.; Gottschald, J.; Bruchmann, J.; Benim, A. C.; Adam, M.; Labs, R.; Herbertz, R. R.; Stunz, A.

    2016-07-01

    The hot forming process of steel requires temperatures of up to 1300°C. Usually, the invested energy is lost to the environment by the subsequent cooling of the forged parts to room temperature. Thermoelectric systems are able to recover this wasted heat by converting the heat into electrical energy and feeding it into the power grid. The proposed thermoelectric system covers an absorption surface of half a square meter, and it is equipped with 50 Bismuth-Telluride based thermoelectric generators, five cold plates, and five inverters. Measurements were performed under production conditions of the industrial environment of the forging process. The heat distribution and temperature profiles are measured and modeled based on the prevailing production conditions and geometric boundary conditions. Under quasi-stationary conditions, the thermoelectric system absorbs a heat radiation of 14.8 kW and feeds electrical power of 388 W into the power grid. The discussed model predicts the measured values with slight deviations.

  16. Cost Scaling of a Real-World Exhaust Waste Heat Recovery Thermoelectric Generator: A Deeper Dive

    NASA Astrophysics Data System (ADS)

    Hendricks, Terry J.; Yee, Shannon; LeBlanc, Saniya

    2016-03-01

    Cost is equally important to power density or efficiency for the adoption of waste heat recovery thermoelectric generators (TEG) in many transportation and industrial energy recovery applications. In many cases, the system design that minimizes cost (e.g., the /W value) can be very different than the design that maximizes the system's efficiency or power density, and it is important to understand the relationship between those designs to optimize TEG performance-cost compromises. Expanding on recent cost analysis work and using more detailed system modeling, an enhanced cost scaling analysis of a waste heat recovery TEG with more detailed, coupled treatment of the heat exchangers has been performed. In this analysis, the effect of the heat lost to the environment and updated relationships between the hot-side and cold-side conductances that maximize power output are considered. This coupled thermal and thermoelectric (TE) treatment of the exhaust waste heat recovery TEG yields modified cost scaling and design optimization equations, which are now strongly dependent on the heat leakage fraction, exhaust mass flow rate, and heat exchanger effectiveness. This work shows that heat exchanger costs most often dominate the overall TE system costs, that it is extremely difficult to escape this regime, and in order to achieve TE system costs of 1/W it is necessary to achieve heat exchanger costs of 1/(W/K). Minimum TE system costs per watt generally coincide with maximum power points, but preferred TE design regimes are identified where there is little cost penalty for moving into regions of higher efficiency and slightly lower power outputs. These regimes are closely tied to previously identified low cost design regimes. This work shows that the optimum fill factor F opt minimizing system costs decreases as heat losses increase, and increases as exhaust mass flow rate and heat exchanger effectiveness increase. These findings have profound implications on the design and

  17. The Universal Influence of Contact Resistance on the Efficiency of a Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Bjørk, Rasmus

    2015-08-01

    The influence of electrical and thermal contact resistance on the efficiency of a segmented thermoelectric generator is investigated. We consider 12 different segmented p-legs and 12 different segmented n-legs, using eight different p-type and eight different n-type thermoelectric materials. For all systems, a universal influence of both the electrical and thermal contact resistance is observed on the leg's efficiency, when the systems are analyzed in terms of the contribution of the contact resistance to the total resistance of the leg. The results are compared with the analytical model of Min and Rowe. In order for the efficiency not to decrease by more than 20%, the contact electrical resistance should be less than 30% of the total leg resistance for zero thermal contact resistance, while the thermal contact resistance should be less than 20% for zero electrical contact resistance. The universal behavior also allowed the maximum tolerable contact resistance for a segmented system to be found, i.e., the resistance at which a leg of only the high-temperature thermoelectric material has the same efficiency as the segmented leg with a contact resistance at the interface. If, e.g., segmentation increases the efficiency by 30%, then an electrical contact resistance of 30% or a thermal contact resistance of 20% can be tolerated.

  18. Analysis of thermoelectric water use in the United States

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoying

    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

  19. A Low-Cost Production Method of FeSi2 Power Generation Thermoelectric Modules

    NASA Astrophysics Data System (ADS)

    Inoue, Hiroyuki; Kobayashi, Takahide; Kato, Masahiko; Yoneda, Seiji

    2016-03-01

    A method is proposed to reduce the production cost of power generation thermoelectric modules. FeSi2 is employed as the thermoelectric material because of its low cost, low environmental load, and oxidation resistance. The raw materials were prepared in the composition of Fe0.96Si2.1Co0.04 for n-type and Fe0.92Si2.1Mn0.08 for p-type, which were added with 0.5 wt.% Cu as the starting materials. They were sintered without pressure at 1446 K to be formed into elements. The Seebeck coefficient and resistivity at room temperature were determined to be -182 μV/K and 0.13 mΩm for n-type, and 338 μV/K and 1.13 mΩm for p-type, respectively. The brazing conditions of the direct joining between the element and the solder were examined. Pastes of BNi-6, BNi-7 or TB-608T were tried as the solder. TB-608T was useable for metallizing of insulation substrates and joining of thermoelectric elements in order to manufacture thermoelectric modules. The joining strength was determined to be 50 MPa between the alumina plate and the elements. No mechanical failure was observed in the modules after repetition of 10 or more exposures to a heat source of 670 K. No change was found in the internal resistance. The present production method will provide modules with high durability and low production cost, which will enable high-power multi-stage cascade modules at a reasonable cost.

  20. Study on the Characteristics of an Alkali-Metal Thermoelectric Power Generation System

    NASA Astrophysics Data System (ADS)

    Lee, Wook-Hyun; Hwang, Hyun-Chang; Lee, Ji-Su; Kim, Pan-Jo; Lim, Sang-Hyuk; Rhi, Seok-Ho; Lee, Kye-Bock; Lee, Ki-Woo

    2015-10-01

    In the present study, a numerical simulation and experimental studies of an alkali-metal thermoelectric energy converter (AMTEC) system were carried out. The present, unique AMTEC model consists of an evaporator, a β-alumina solid electrolyte (BASE) tube, a condenser, and an artery cable wick. The key points for operation of the present AMTEC were 1100 K in the evaporator and 600 K in the condenser. A numerical model based on sodium-saturated porous wicks was developed and shown to be able to simulate the AMTEC system. The simulation results show that the AMTEC system can generate up to 100 W with a given design. The AMTEC system developed in the present work and used in the practical investigations could generate an electromotive force of 7 V. Artery wick and evaporator wick structures were simulated for the optimum design. Both sodium-saturated wicks were affected by numerous variables, such as the input heat power, cooling temperature, sodium mass flow rate, and capillary-driven fluid flow. Based on an effective thermal conductivity model, the presented simulation could successfully predict the system performance. Based on the numerical simulation, the AMTEC system operates with efficiency near 10% to 15%. In the case of an improved BASE design, the system could reach efficiency of over 30%. The system was designed for 0.6 V power, 25 A current, and 100 W power input. In addition, in this study, the temperature effects in each part of the AMTEC system were analyzed using a heat transfer model in porous media to apply to the computational fluid dynamics at a predetermined temperature condition for the design of a 100-W AMTEC prototype. It was found that a current density of 0.5 A/cm2 to 0.9 A/cm2 for the BASE is suitable when the temperatures of the evaporator section and condenser section are 1100 K and 600 K, respectively.

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

    SciTech Connect

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

    2006-01-20

    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 and 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 from the design philosophy of the past which was to match specific mission requirements to RTG design capabilities. Undefined mission requirements provide a challenge to system designers by forcing them to put a design envelope around 'all possible missions'. These multi-mission requirements include internal and external radiation sources. Internal sources include the particles ejected by decaying Pu-238 and its daughters plus particles resulting from the interaction of these particles with other MMRTG materials. External sources include the full spectrum of charged particle radiation surrounding planets with magnetic fields and the surfaces of extraterrestrial objects not shielded by magnetic fields. The paper presents the results of investigations into the environments outlined above and the impact of radiation exposure on potential materials to be used on MMRTG and ground support personnel. Mission requirements were also reviewed to evaluate total integrated dose and to project potential shielding requirements for materials. Much of the information on mission shielding requirements was provided by NASA's Jet Propulsion Laboratory. The primary result is an ionizing radiation design curve which indicates the limits to which a particular mission can take the MMRTG in terms of ionizing radiation exposure. Estimates of personnel radiation exposure during ground handling are also provided.

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

    NASA Astrophysics Data System (ADS)

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

    2006-01-01

    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 from the design philosophy of the past which was to match specific mission requirements to RTG design capabilities. Undefined mission requirements provide a challenge to system designers by forcing them to put a design envelope around ``all possible missions''. These multi-mission requirements include internal and external radiation sources. Internal sources include the particles ejected by decaying Pu-238 and its daughters plus particles resulting from the interaction of these particles with other MMRTG materials. External sources include the full spectrum of charged particle radiation surrounding planets with magnetic fields and the surfaces of extraterrestrial objects not shielded by magnetic fields. The paper presents the results of investigations into the environments outlined above and the impact of radiation exposure on potential materials to be used on MMRTG and ground support personnel. Mission requirements were also reviewed to evaluate total integrated dose and to project potential shielding requirements for materials. Much of the information on mission shielding requirements was provided by NASA's Jet Propulsion Laboratory. The primary result is an ionizing radiation design curve which indicates the limits to which a particular mission can take the MMRTG in terms of ionizing radiation exposure. Estimates of personnel radiation exposure during ground handling are also provided.

  3. Development of a Thermoelectric Module Suitable for Vehicles and Based on CoSb3 Manufactured Close to Production

    NASA Astrophysics Data System (ADS)

    Klein Altstedde, Mirko; Sottong, Reinhard; Freitag, Oliver; Kober, Martin; Dreißigacker, Volker; Zabrocki, Knud; Szabo, Patric

    2015-06-01

    Despite the ongoing electrification of vehicle propulsion systems, vehicles with combustion engines will continue to bear the brunt of passenger services worldwide for the next few decades. As a result, the German Aerospace Center Institute of Vehicle Concepts, the Institute of Materials Research and the Institute of Technical Thermodynamics have focused on utilising the exhaust heat of internal combustion engines by means of thermoelectric generators (TEGs). Their primary goal is the development of cost-efficient TEGs with long-term stability and maximised energy yield. In addition to the overall TEG system design, the development of long-term stable, efficient thermoelectric modules (TEMs) for high-temperature applications is a great challenge. This paper presents the results of internal development work and reveals an expedient module design for use in TEGs suitable for vehicles. The TEM requirements identified, which were obtained by means of experiments on the test vehicle and test bench, are described first. Doped semiconductor materials were produced and characterised by production methods capable of being scaled up in order to represent series application. The results in terms of thermoelectric properties (Seebeck coefficient, electrical conductivity and thermal conductivity) were used for the simulative design of a thermoelectric module using a constant-property model and with the aid of FEM calculations. Thermomechanical calculations of material stability were carried out in addition to the TEM's thermodynamic and thermoelectric design. The film sequence within the module represented a special challenge. Multilayer films facilitated adaptation of the thermal and mechanical properties of plasma-sprayed films. A joint which dispenses with solder additives was also possible using multilayer films. The research resulted in a functionally-optimised module design, which was enhanced for use in motor vehicles using process flexibility and close

  4. Detailed mathematical models of a radioisotope thermoelectric generator.

    NASA Technical Reports Server (NTRS)

    Dewinter, F.; Raag, V.

    1972-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Sasaki, Keiichi; Horikawa, Daisuke; Goto, Koichi

    2015-01-01

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

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

    PubMed

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

    2013-01-01

    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

  7. Climate change impacts on thermoelectric-power generation in the United States

    NASA Astrophysics Data System (ADS)

    Liu, L.

    2015-12-01

    Thermoelectric-power generation accounts for more than 70% of the total electricity generation in the United States, which requires large amounts of water for cooling purposes. Water withdrawals for thermoelectric-power generation accounted for 45% of total water use in the United States in 2010. Across the country, water demand from power plants is increasing due to pressures from growing populations and other needs, and is straining existing water resources. Moreover, temperature exceedance in receiving waters has increasingly caused power plants shut downs across parts of the country. Thermoelectric power is vulnerable to climate change owing to the combined effects of lower summer river flows and higher receiving water temperatures. In addition, the efficiency of production is reduced as air temperature rises, which propagates to more unfulfilled power demand during peak seasons. Therefore, a holistic modeling framework of water-energy-climate for the contiguous U.S. is presented here to quantify thermal output from power plants and estimate water use and energy production fluctuations due to ambient climate as well as environmental regulations. The model is calibrated on a plant-by-plant basis for year 2010 and 2011 using the available power plant inventory from the Energy Information Administration (EIA). Simulations were carried out for years 2012 and 2013, and results show moderate improvements in capturing thermal output variabilities after calibration. Future power plant operations under scenarios featuring different climate and regulatory settings were investigated. Results demonstrate the interplay among water, energy and climate, and that future changes in climate and socioeconomics significantly affect power plant operations, which may provide insights to climate change mitigation considerations and energy decisions.

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

    SciTech Connect

    Li, Qiang

    2009-04-30

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

  9. Modular Radioisotope Thermoelectric Generator (RTG) Program. Final technical report

    SciTech Connect

    Not Available

    1992-12-31

    Section 2.0 of this report summarizes the MOD-RTG reference flight design, and Section 3.0 discusses the Ground Demonstration System design. Multicouple technology development is discussed in Section 4.0, and Section 5.0 lists all published technical papers prepared during the course of the contract.

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

    SciTech Connect

    Hosseini, A.; Standring, W.J.F.; Brown, J.E.; Dowdall, M.; Amundsen, I.B.

    2007-07-01

    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)

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

    NASA Astrophysics Data System (ADS)

    McAlonan, Malachy; Patel, Kalpesh; Cummer, Keith

    2006-01-01

    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

  12. Potential improvements in SiGe radioisotope thermoelectric generator performance

    SciTech Connect

    Mowery, A.L.

    1999-01-01

    In accordance with NASA{close_quote}s slogan: {open_quotes}Better, Cheaper, Faster,{close_quotes} this paper will address potential improvements to SiGe RTG technology to make them Better. RTGs are doubtless cheaper than {open_quotes}paper designs{close_quotes} which are better and cheaper until development, performance and safety test costs are considered. RTGs have the advantage of being fully developed and tested in the rigors of space for over twenty years. Further, unless a new system can be accelerated tested, as were the RTGs, they cannot be deployed reliably unless a number of systems have succeeded for test periods exceeding the mission lifetime. Two potential developments are discussed that can improve the basic RTG performance by 10 to 40{sup +}{percent} depending on the mission profile. These improvements could be demonstrated in years. Accelerated testing could also be performed in this period to preserve existing RTG reliability. Data from a qualification tested RTG will be displayed, while not definitive, to support the conclusions. Finally, it is anticipated that other investigators will be encouraged to suggest further modifications to the basic RTG design to improve its performance. {copyright} {ital 1999 American Institute of Physics.}

  13. Potential improvements in SiGe radioisotope thermoelectric generator performance

    NASA Astrophysics Data System (ADS)

    Mowery, Alfred L.

    1999-01-01

    In accordance with NASA's slogan: ``Better, Cheaper, Faster,'' this paper will address potential improvements to SiGe RTG technology to make them Better. RTGs are doubtless cheaper than ``paper designs'' which are better and cheaper until development, performance and safety test costs are considered. RTGs have the advantage of being fully developed and tested in the rigors of space for over twenty years. Further, unless a new system can be accelerated tested, as were the RTGs, they cannot be deployed reliably unless a number of systems have succeeded for test periods exceeding the mission lifetime. Two potential developments are discussed that can improve the basic RTG performance by 10 to 40+% depending on the mission profile. These improvements could be demonstrated in years. Accelerated testing could also be performed in this period to preserve existing RTG reliability. Data from a qualification tested RTG will be displayed, while not definitive, to support the conclusions. Finally, it is anticipated that other investigators will be encouraged to suggest further modifications to the basic RTG design to improve its performance.

  14. Numerical Modeling of Year-Round Performance of a Solar Parabolic Dish Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Muthu, G.; Shanmugam, S.; Veerappan, AR.

    2015-08-01

    This paper presents the year-round performance of a solar parabolic dish thermoelectric generator under different values of operating parameters such as ambient temperature, wind velocity, direct normal irradiation, and water inlet temperature to the heat sink. The solar thermoelectric generator (TEG) is examined for an Indian location of Tiruchirappalli. The electrical power output and TEG efficiency are maximum during the months of April and August, while they are minimum during the month of December. It is found that the monthly average hot-side temperature of the TEG varies from 556.53 K to 592.68 K and the cold-side temperature of the TEG varies from 413.21 K to 438.91 K. When the hot-side temperature reaches the optimum value, the conversion efficiency is reduced, although the power increases. A TEG model is useful to find the temperature of the junctions for different operating parameter values and predict the performance of the TEG at any time. A small standalone power-generating system using this technology is a promising option.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

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

    NASA Astrophysics Data System (ADS)

    Yazawa, Kazuaki; Shakouri, Ali

    2013-07-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Faraji, Amir Yadollah; Akbarzadeh, Aliakbar

    2013-07-01

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

  18. Thermoelectric power conversion in space

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Kühn, Roland; Koeppen, Olaf; Kitte, Jens

    2014-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  2. Enhanced performance of dispenser printed MA n-type Bi₂Te₃ composite thermoelectric generators.

    PubMed

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

    2012-11-01

    This work presents performance advancements of dispenser printed composite thermoelectric materials and devices. Dispenser printed thick films allow for low-cost and scalable manufacturing of microscale energy harvesting devices. A maximum ZT value of 0.31 has been achieved for mechanically alloyed (MA) n-type Bi₂Te₃-epoxy composite films with 1 wt % Se cured at 350 °C. The enhancement of ZT is a result of increase in the electrical conductivity through the addition of Se, which ultimately lowers the sintering temperature (350 °C). A 62 single-leg thermoelectric generator (TEG) prototype with 5 mm ×700 μm × 120 μm printed element dimensions was fabricated on a custom designed polyimide substrate with thick metal contacts. The prototype device produced a power output of 25 μW at 0.23 mA current and 109 mV voltage for a temperature difference of 20 °C, which is sufficient for low power generation for autonomous microsystem applications. PMID:23130550

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

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

    SciTech Connect

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

    1983-04-01

    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.

  5. Spin-current-driven thermoelectric generation based on interfacial spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Yagmur, A.; Karube, S.; Uchida, K.; Kondou, K.; Iguchi, R.; Kikkawa, T.; Otani, Y.; Saitoh, E.

    2016-06-01

    The longitudinal spin Seebeck effect (SSE) in Bi2O3/Cu/yttrium-iron-garnet (YIG) devices has been investigated. When an out-of-plane temperature gradient is applied to the Bi2O3/Cu/YIG device, a spin current is generated across the Cu/YIG interface via the SSE and then converted into electric voltage due to the spin-orbit coupling at the Bi2O3/Cu interface. The sign of the SSE voltage in the Bi2O3/Cu/YIG devices is opposite to that induced by the conventional inverse spin Hall effect in Pt/YIG devices. The SSE voltage in the Bi2O3/Cu/YIG devices disappears in the absence of the Bi2O3 layer and its thermoelectric conversion efficiency is independent of the Cu thickness, indicating the important role of the Bi2O3/Cu interface. This result demonstrates that not only the bulk inverse spin Hall effect but also the spin-orbit coupling near the interface can be used for SSE-based thermoelectric generation.

  6. Facile Preparation of Highly Conductive Metal Oxides by Self-Combustion for Solution-Processed Thermoelectric Generators.

    PubMed

    Kang, Young Hun; Jang, Kwang-Suk; Lee, Changjin; Cho, Song Yun

    2016-03-01

    Highly conductive indium zinc oxide (IZO) thin films were successfully fabricated via a self-combustion reaction for application in solution-processed thermoelectric devices. Self-combustion efficiently facilitates the conversion of soluble precursors into metal oxides by lowering the required annealing temperature of oxide films, which leads to considerable enhancement of the electrical conductivity of IZO thin films. Such enhanced electrical conductivity induced by exothermic heat from a combustion reaction consequently yields high performance IZO thermoelectric films. In addition, the effect of the composition ratio of In to Zn precursors on the electrical and thermoelectric properties of the IZO thin films was investigated. IZO thin films with a composition ratio of In:Zn = 6:2 at the low annealing temperature of 350 °C showed an enhanced electrical conductivity, Seebeck coefficient, and power factor of 327 S cm(-1), 50.6 μV K(-1), and 83.8 μW m(-1) K(-2), respectively. Moreover, the IZO thin film prepared at an even lower temperature of 300 °C retained a large power factor of 78.7 μW m(-1) K(-2) with an electrical conductivity of 168 S cm(-1). Using the combustive IZO precursor, a thermoelectric generator consisting of 15 legs was fabricated by a printing process. The thermoelectric array generated a thermoelectric voltage of 4.95 mV at a low temperature difference (5 °C). We suggest that the highly conductive IZO thin films by self-combustion may be utilized for fabricating n-type flexible printed thermoelectric devices. PMID:26856774

  7. The Influence of a Dispersion Cone on the Temperature Distribution in the Heat Exchanger of a Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    MusiaŁ, M.; Borcuch, M.; Wojciechowski, K.

    2016-03-01

    This paper presents the results of a numerical simulation of heat distribution in the heat exchanger of a prototype thermoelectric generator constructed and examined in the Thermoelectric Research Laboratory in AGH University, Cracow, Poland. The area of interest was to prepare a numerical model and determine the influence of a dispersion cone on the temperature distribution along the heat exchanger. The role of a dispersion element is to mix the air stream to improve the flow between the internal heat exchanger's fins in order to enhance heat exchange. The estimation of power output parameters and exchanger efficiency has been performed in order to assess the cone impact for three selected air inlet temperatures. The results show that the presence of the cone increases the efficiency of the thermoelectric generator by at least 25%.

  8. Effect of the Sequence of the Thermoelectric Generator and the Three-Way Catalytic Converter on Exhaust Gas Conversion Efficiency

    NASA Astrophysics Data System (ADS)

    Su, Chuqi; Tong, Naiqiang; Xu, Yuman; Chen, Shan; Liu, Xun

    2013-07-01

    The potential for thermoelectric exhaust heat recovery in vehicles has increased with recent improvements in the efficiency of thermoelectric generators (TEGs). The problem with using thermoelectric generators for vehicle applications is whether the device is compatible with the original vehicle exhaust system, which determines the quality of the exhaust gas treatment and the realization of energy conservation and emission reduction. Based on ANSYS CFX simulation analysis of the impact of two positional relationships between the TEG and three-way catalytic converter in the exhaust system on the working efficiency of both elements, it is concluded that the layout with the front three-way catalytic converter has an advantage over the other layout mode under current conditions. New ideas for an improvement program are proposed to provide the basis for further research.

  9. Solar thermoelectric generators fabricated on a silicon-on-insulator substrate

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    Solar thermal power generation is an attractive electricity generation technology as it is environment-friendly, has the potential for increased efficiency, and has high reliability. The design, modelling, and evaluation of solar thermoelectric generators (STEGs) fabricated on a silicon-on-insulator substrate are presented in this paper. Solar concentration is achieved by using a focusing lens to concentrate solar input onto the membrane of the STEG. A thermal model is developed based on energy balance and heat transfer equations using lumped thermal conductances. This thermal model is shown to be in good agreement with actual measurement results. For a 1 W laser input with a spot size of 1 mm, a maximum open-circuit voltage of 3.06 V is obtained, which translates to a temperature difference of 226 °C across the thermoelements and delivers 25 µW of output power under matched load conditions. Based on solar simulator measurements, a maximum TEG voltage of 803 mV was achieved by using a 50.8 mm diameter plano-convex lens to focus solar input to a TEG with a length of 1000 µm, width of 15 µm, membrane diameter of 3 mm, and 114 thermocouples. This translates to a temperature difference of 18 °C across the thermoelements and an output power under matched load conditions of 431 nW. This paper demonstrates that by utilizing a solar concentrator to focus solar radiation onto the hot junction of a TEG, the temperature difference across the device is increased; subsequently improving the TEG’s efficiency. By using materials that are compatible with standard CMOS and MEMS processes, integration of solar-driven TEGs with on-chip electronics is seen to be a viable way of solar energy harvesting where the resulting microscale system is envisioned to have promising applications in on-board power sources, sensor networks, and autonomous microsystems.

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

    SciTech Connect

    Gregory Meisner

    2011-08-31

    We conducted a vehicle analysis to assess the feasibility of thermoelectric technology for waste heat recovery and conversion to useful electrical power and found that eliminating the 500 W of electrical power generated by the alternator corresponded to about a 7% increase in fuel economy (FE) for a small car and about 6% for a full size truck. Electric power targets of 300 W were established for city and highway driving cycles for this project. We obtained critical vehicle level information for these driving cycles that enabled a high-level design and performance analysis of radiator and exhaust gas thermoelectric subsystems for several potential vehicle platforms, and we identified the location and geometric envelopes of the radiator and exhaust gas thermoelectric subsystems. Based on this analysis, we selected the Chevrolet Suburban as the most suitable demonstration vehicle for this project. Our modeling and thermal analysis assessment of a radiator-based thermoelectric generator (TEG), however, revealed severe practical limitations. Specifically the small temperature difference of 100°C or less between the engine coolant and ambient air results in a low Carnot conversion efficiency, and thermal resistance associated with air convection would reduce this conversion efficiency even further. We therefore decided not to pursue a radiator-based waste heat recovery system and focused only on the exhaust gas. Our overall approach was to combine science and engineering: (1) existing and newly developed TE materials were carefully selected and characterized by the material researcher members of our team, and most of the material property results were validated by our research partners, and (2) system engineers worked closely with vehicle engineers to ensure that accurate vehicle-level information was used for developing subsystem models and designs, and the subsystem output was analyzed for potential fuel economy gains. We incorporated material, module, subsystem

  11. Device for use in a furnace exhaust stream for thermoelectric generation

    DOEpatents

    Polcyn, Adam D.

    2013-06-11

    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.

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

    NASA Technical Reports Server (NTRS)

    Stapfer, G.; Truscello, V. C.

    1976-01-01

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

  13. Thermoelectric Power Generation from Lanthanum Strontium Titanium Oxide at Room Temperature through the Addition of Graphene.

    PubMed

    Lin, Yue; Norman, Colin; Srivastava, Deepanshu; Azough, Feridoon; Wang, Li; Robbins, Mark; Simpson, Kevin; Freer, Robert; Kinloch, Ian A

    2015-07-29

    The applications of strontium titanium oxide based thermoelectric materials are currently limited by their high operating temperatures of >700 °C. Herein, we show that the thermal operating window of lanthanum strontium titanium oxide (LSTO) can be reduced to room temperature by the addition of a small amount of graphene. This increase in operating performance will enable future applications such as generators in vehicles and other sectors. The LSTO composites incorporated one percent or less of graphene and were sintered under an argon/hydrogen atmosphere. The resultant materials were reduced and possessed a multiphase structure with nanosized grains. The thermal conductivity of the nanocomposites decreased upon the addition of graphene, whereas the electrical conductivity and power factor both increased significantly. These factors, together with a moderate Seebeck coefficient, meant that a high power factor of ∼2500 μWm(-1)K(-2) was reached at room temperature at a loading of 0.6 wt % graphene. The highest thermoelectric figure of merit (ZT) was achieved when 0.6 wt % graphene was added (ZT = 0.42 at room temperature and 0.36 at 750 °C), with >280% enhancement compared to that of pure LSTO. A preliminary 7-couple device was produced using bismuth strontium cobalt oxide/graphene-LSTO pucks. This device had a Seebeck coefficient of ∼1500 μV/K and an open voltage of 600 mV at a mean temperature of 219 °C. PMID:26095083

  14. Analysis of the Effect of Module Thickness Reduction on Thermoelectric Generator Output

    NASA Astrophysics Data System (ADS)

    Brito, F. P.; Figueiredo, L.; Rocha, L. A.; Cruz, A. P.; Goncalves, L. M.; Martins, J.; Hall, M. J.

    2016-03-01

    Conventional thermoelectric generators (TEGs) used in applications such as exhaust heat recovery are typically limited in terms of power density due to their low efficiency. Additionally, they are generally costly due to the bulk use of rare-earth elements such as tellurium. If less material could be used for the same output, then the power density and the overall cost per kilowatt (kW) of electricity produced could drop significantly, making TEGs a more attractive solution for energy harvesting of waste heat. The present work assesses the effect of reducing the amount of thermoelectric (TE) material used (namely by reducing the module thickness) on the electrical output of conventional bismuth telluride TEGs. Commercial simulation packages (ANSYS CFX and thermal-electric) and bespoke models were used to simulate the TEGs at various degrees of detail. Effects such as variation of the thermal and electrical contact resistance and the component thickness and the effect of using an element supporting matrix (e.g., eggcrate) instead of having air conduction in void areas have been assessed. It was found that indeed it is possible to reduce the use of bulk TE material while retaining power output levels equivalent to thicker modules. However, effects such as thermal contact resistance were found to become increasingly important as the active TE material thickness was decreased.

  15. Efficiency Study of a Commercial Thermoelectric Power Generator (TEG) Under Thermal Cycling

    NASA Astrophysics Data System (ADS)

    Hatzikraniotis, E.; Zorbas, K. T.; Samaras, I.; Kyratsi, Th.; Paraskevopoulos, K. M.

    2010-09-01

    Thermoelectric generators (TEGs) make use of the Seebeck effect in semiconductors for the direct conversion of heat to electrical energy. The possible use of a device consisting of numerous TEG modules for waste heat recovery from an internal combustion (IC) engine could considerably help worldwide efforts towards energy saving. However, commercially available TEGs operate at temperatures much lower than the actual operating temperature range in the exhaust pipe of an automobile, which could cause structural failure of the thermoelectric elements. Furthermore, continuous thermal cycling could lead to reduced efficiency and lifetime of the TEG. In this work we investigate the long-term performance and stability of a commercially available TEG under temperature and power cycling. The module was subjected to sequential hot-side heating (at 200°C) and cooling for long times (3000 h) in order to measure changes in the TEG’s performance. A reduction in Seebeck coefficient and an increase in resistivity were observed. Alternating-current (AC) impedance measurements and scanning electron microscope (SEM) observations were performed on the module, and results are presented and discussed.

  16. Thermoelectric Polymers and their Elastic Aerogels.

    PubMed

    Khan, Zia Ullah; Edberg, Jesper; Hamedi, Mahiar Max; Gabrielsson, Roger; Granberg, Hjalmar; Wågberg, Lars; Engquist, Isak; Berggren, Magnus; Crispin, Xavier

    2016-06-01

    Electronically conducting polymers constitute an emerging class of materials for novel electronics, such as printed electronics and flexible electronics. Their properties have been further diversified to introduce elasticity, which has opened new possibility for "stretchable" electronics. Recent discoveries demonstrate that conducting polymers have thermoelectric properties with a low thermal conductivity, as well as tunable Seebeck coefficients - which is achieved by modulating their electrical conductivity via simple redox reactions. Using these thermoelectric properties, all-organic flexible thermoelectric devices, such as temperature sensors, heat flux sensors, and thermoelectric generators, are being developed. In this article we discuss the combination of the two emerging fields: stretchable electronics and polymer thermoelectrics. The combination of elastic and thermoelectric properties seems to be unique for conducting polymers, and difficult to achieve with inorganic thermoelectric materials. We introduce the basic concepts, and state of the art knowledge, about the thermoelectric properties of conducting polymers, and illustrate the use of elastic thermoelectric conducting polymer aerogels that could be employed as temperature and pressure sensors in an electronic-skin. PMID:26836440

  17. Development of Thermoelectric and Permanent Magnet Nanoparticles for Clean Energy Applications

    NASA Astrophysics Data System (ADS)

    Nguyen, Phi-Khanh

    The global trend towards energy efficiency and environmental sustainability has generated a strong demand for clean energy technologies. Among the many energy solutions, the work in this dissertation contributes to two strategic goals: the reduction of fuel consumption in the transportation sector, and the increase of domestic wind power capacity. The key barriers to achieving these goals are materials challenges. Automobiles can be made more efficient by thermoelectric conversion of waste heat from the engine into electricity that can be used to power electrical components in the vehicle. Vehicles can forego petroleum fuel altogether by using electric or hybrid motors. Unfortunately, the conversion efficiency of current thermoelectric technology is too low to be considered economically feasible, and the permanent magnets used in electric vehicle motors and wind turbine generators require critical rare-earth elements that are economically unstable (often referred to as the "rare-earth crisis"). In order to combat these challenges, a "spark erosion" technique was utilized for producing nanoparticles that improve thermoelectric efficiency and contribute to the development of electromotors that do not require rare-earths. In Chapter 2 of this dissertation, I describe the utilization of spark erosion for producing high-quality thermoelectric nanoparticles at a remarkably high rate and with enhanced thermoelectric properties. The technique was employed to synthesize p-type bismuth-antimony telluride (BST) and n-type skutterudite nanoparticles, using a relatively small laboratory apparatus, with low energy consumption. The compacted BST nanocomposite samples made from these nanoparticles exhibit a well-defined, 20--50 nm size nanograin microstructure, and show an enhanced Figure of merit, ZT, of 1.36 at 360 K due to a reduction in lattice thermal conductivity. The skutterudite nanocomposites also show reduced thermal conductivity but still require enhancement in the

  18. Resolving thermoelectric "paradox" in superconductors.

    PubMed

    Shelly, Connor D; Matrozova, Ekaterina A; Petrashov, Victor T

    2016-02-01

    For almost a century, thermoelectricity in superconductors has been one of the most intriguing topics in physics. During its early stages in the 1920s, the mere existence of thermoelectric effects in superconductors was questioned. In 1944, it was demonstrated that the effects may occur in inhomogeneous superconductors. Theoretical breakthrough followed in the 1970s, when the generation of a measurable thermoelectric magnetic flux in superconducting loops was predicted; however, a major crisis developed when experiments showed puzzling discrepancies with the theory. Moreover, different experiments were inconsistent with each other. This led to a stalemate in bringing theory and experiment into agreement. With this work, we resolve this stalemate, thus solving this long-standing "paradox," and open prospects for exploration of novel thermoelectric phenomena predicted recently. PMID:26933688

  19. Infrared and thermoelectric power generation in thin atomic layer deposited Nb-doped TiO{sub 2} films

    SciTech Connect

    Mann, Harkirat S.; Lang, Brian N.; Schwab, Yosyp; Scarel, Giovanna; Niemelä, Janne-Petteri; Karppinen, Maarit

    2015-01-15

    Infrared radiation is used to radiatively transfer heat to a nanometric power generator (NPG) device with a thermoelectric Nb-doped TiO{sub 2} film deposited by atomic layer deposition (ALD) as the active element, onto a borosilicate glass substrate. The linear rise of the produced voltage with respect to the temperature difference between the “hot” and “cold” junctions, typical of the Seebeck effect, is missing. The discovery of the violation of the Seebeck effect in NPG devices combined with the ability of ALD to tune thermoelectric thin film properties could be exploited to increase the efficiency of these devices for energy harvesting purposes.

  20. Numerical and Experimental Investigation for Heat Transfer Enhancement by Dimpled Surface Heat Exchanger in Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Wang, Yiping; Li, Shuai; Yang, Xue; Deng, Yadong; Su, Chuqi

    2016-03-01

    For vehicle thermoelectric exhaust energy recovery, the temperature difference between the heat exchanger and the coolant has a strong influence on the electric power generation, and ribs are often employed to enhance the heat transfer of the heat exchanger. However, the introduction of ribs will result in a large unwanted pressure drop in the exhaust system which is unfavorable for the engine's efficiency. Therefore, how to enhance the heat transfer and control the pressure drop in the exhaust system is quite important for thermoelectric generators (TEG). In the current study, a symmetrical arrangement of dimpled surfaces staggered in the upper and lower surfaces of the heat exchanger was proposed to augment heat transfer rates with minimal pressure drop penalties. The turbulent flow characteristics and heat transfer performance of turbulent flow over the dimpled surface in a flat heat exchanger was investigated by numerical simulation and temperature measurements. The heat transfer capacity in terms of Nusselt number and the pressure loss in terms of Fanning friction factors of the exchanger were compared with those of the flat plate. The pressure loss and heat transfer characteristics of dimples with a depth-to-diameter ratio ( h/D) at 0.2 were investigated. Finally, a quite good heat transfer performance with minimal pressure drop heat exchanger in a vehicle TEG was obtained. And based on the area-averaged surface temperature of the heat exchanger and the Seeback effect, the power generation can be improved by about 15% at Re = 25,000 compared to a heat exchanger with a flat surface.

  1. Synthetic thermoelectric materials comprising phononic crystals

    SciTech Connect

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

    2013-08-13

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    Semiconducting large bandgap oxides are considered as interesting candidates for high-temperature thermoelectric power generation (700-1,200 °C) due to their stability, lack of toxicity and low cost, but so far they have not reached sufficient performance for extended application. In this review, we summarize recent progress on thermoelectric oxides, analyze concepts for tuning semiconductor thermoelectric properties with view of their applicability to oxides and determine key drivers and limitations for electrical and thermal transport properties in oxides based on our own experimental work and literature results. For our experimental assessment, we have selected representative multicomponent oxides that range from materials with highly symmetric crystal structure (SrTiO3 perovskite) over oxides with large densities of planar crystallographic defects (Ti n O2 n-1 Magnéli phases with a single type of shear plane, NbO x block structures with intersecting shear planes and WO3- x with more defective block and channel structures) to layered superstructures (Ca3Co4O9 and double perovskites) and also include a wide range of their composites with a variety of second phases. Crystallographic or microstructural features of these oxides are in 0.3-2 nm size range, so that oxide phonons can efficiently interact with them. We explore in our experiments the effects of doping, grain size, crystallographic defects, superstructures, second phases, texturing and (to a limited extend) processing on electric conductivity, Seebeck coefficient, thermal conductivity and figure of merit. Jonker and lattice-versus-electrical conductivity plots are used to compare specific materials and material families and extract levers for future improvement of oxide thermoelectrics. We show in our work that oxygen vacancy doping (reduction) is a more powerful driver for improving the power factor for SrTiO3, TiO2 and NbO x than heterovalent doping. Based on our Seebeck-conductivity plots, we derived

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

    SciTech Connect

    Xu, B. Fobelets, K.

    2014-06-07

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

  4. Quality Assurance Plan for Heat Source/Radioisotope Thermoelectric Generator Programs

    SciTech Connect

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

    1995-03-16

    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.

  5. The application of solar thermoelectric generators in near-sun missions

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  6. SNAP 19 Viking RTG flight configuration and integration testing. [Radioisotope Thermoelectric Generator

    NASA Technical Reports Server (NTRS)

    Brittain, W. M.; Christenbury, S. T.

    1974-01-01

    The Viking-75 mission environments and lander interface requirements which influence the design of the RTG (radioisotope thermoelectric generator), as well as RTG-related constraints are discussed. The baseline RTG design evolved from these considerations is presented with particular emphasis on the design features which make the Viking RTG unique. These features include a gas management system employing a separate gas reservoir to maintain the RTG hot junction and heat source temperatures within a desired range throughout the various mission phases, as well as a specially profiled housing/radiator assembly which facilitates both ground cooling of the RTGs prior to launch and thermal control of the lander after landing. Also presented is the expected RTG electrical performance when subjected to the various mission environments/requirements, such as 'power-up' operations in Mars orbit just prior to the entry, and thermal cycling on the Martian surface after landing.

  7. The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system

    NASA Astrophysics Data System (ADS)

    Bjørk, R.; Nielsen, K. K.

    2015-10-01

    The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system is examined using an analytical model for four different types of commercial PVs and a commercial bismuth telluride TEG. The TEG is applied directly on the back of the PV, so that the two devices have the same temperature. The PVs considered are crystalline Si (c-Si), amorphous Si (a-Si), copper indium gallium (di)selenide (CIGS) and cadmium telluride (CdTe) cells. The degradation of PV performance with temperature is shown to dominate the increase in power produced by the TEG, due to the low efficiency of the TEG. For c-Si, CIGS and CdTe PV cells the combined system produces a lower power and has a lower efficiency than the PV alone, whereas for an a-Si cell the total system performance may be slightly increased by the TEG.

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

    DOEpatents

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

    2013-05-21

    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.

  9. RTG's for space exploration at the end of the 20th century. [radioisotope thermoelectric generators

    NASA Technical Reports Server (NTRS)

    Chmielewski, Art

    1989-01-01

    The use of radioisotope thermoelectric generators (RTGs) as energy conversion devices for spacecraft designed for weak-sunlight environments is discussed. The two upcoming missions Galileo and Ulysses will both use general-purpose heat source RTGs. Two other missions that are planned for the mid-nineties and will carry RTGs onboard are the comet rendezvous asteroid flyby and Cassini. Another mission that might become a program start in the last decade of the 20th century is Solarprobe, which is most likely to use modular RTGs. Several other missions that are in different planning stages that are in need of RTGs to meet their power requirements are the Mars rover sample return, planetary (Mars) penetrators, microspacecraft, and the Mars Egg. All of these missions are discssed, stressing their RTG requirements.

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

    DOEpatents

    Prior, Gregory P

    2012-10-30

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

  11. Highly Efficient Multilayer Thermoelectric Devices

    NASA Technical Reports Server (NTRS)

    Boufelfel, Ali

    2006-01-01

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

  12. Development and Testing of an Integrated Sandia Cooler Thermoelectric Device (SCTD).

    SciTech Connect

    Johnson, Terry A.; Staats, Wayne Lawrence,; Leick, Michael Thomas; Zimmerman, Mark D.; Radermacher, Reinhard; Martin, Cara; Nasuta, Dennis; Kalinowski, Paul; Hoffman, William

    2014-12-01

    This report describes a FY14 effort to develop an integrated Sandia Cooler T hermoelectric D evice (SCTD) . The project included a review of feasible thermoelectric (TE) cooling applications, baseline performance testing of an existing TE device, analysis and design development of an integrated SCTD assembly, and performance measurement and validation of the integrated SCTD prototype.

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    The addition of the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) to the Mars Science Laboratory (MSL) Rover requires an advanced thermal control system that is able to both recover and reject the waste heat from the MMRTG as needed in order to maintain the onboard electronics at benign temperatures despite the extreme and widely varying environmental conditions experienced both on the way to Mars and on the Martian surface. Based on the previously successful Mars landed mission thermal control schemes, a mechanically pumped fluid loop (MPFL) architecture was selected as the most robust and efficient means for meeting the MSL thermal requirements. The MSL heat recovery and rejection system (HRS) is comprised of two Freon (CFC-11) MPFLs that interact closely with one another to provide comprehensive thermal management throughout all mission phases. The first loop, called the Rover HRS (RHRS), consists of a set of pumps, thermal control valves, and heat exchangers (HXs) that enables the transport of heat from the MMRTG to the rover electronics during cold conditions or from the electronics straight to the environment for immediate heat rejection during warm conditions. The second loop, called the Cruise HRS (CHRS), is thermally coupled to the RHRS during the cruise to Mars, and provides a means for dissipating the waste heat more directly from the MMRTG as well as from both the cruise stage and rover avionics by promoting circulation to the cruise stage radiators. A multifunctional structure was developed that is capable of both collecting waste heat from the MMRTG and rejecting the waste heat to the surrounding environment. It consists of a pair of honeycomb core sandwich panels with HRS tubes bonded to both sides. Two similar HX assemblies were designed to surround the MMRTG on the aft end of the rover. Heat acquisition is accomplished on the interior (MMRTG facing) surface of each HX while heat rejection is accomplished on the exterior surface of

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

    SciTech Connect

    Goebel, C.J.

    1990-01-01

    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.

  16. Universal thermoelectric unit

    SciTech Connect

    Fedorov, M.I.; Engalychev, A.E.; Zaitsev, V.K.; Kaliazin, A.E.; Solomkin, F.Y.

    1994-08-10

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

  17. Development of a prototype thermoelectric space cooling system using phase change material to improve the performance

    NASA Astrophysics Data System (ADS)

    Zhao, Dongliang

    The thermoelectric cooling system has advantages over conventional vapor compression cooling devices, including compact in size, light in weight, high reliability, no mechanical moving parts, no refrigerant, being powered by direct current, and easily switching between cooling and heating modes. However, it has been long suffering from its relatively high cost and low energy efficiency, which has restricted its usage to niche applications, such as space missions, portable cooling devices, scientific and medical equipment, where coefficient of performance (COP) is not as important as reliability, energy availability, and quiet operation environment. Enhancement of thermoelectric cooling system performance generally relies on two methods: improving thermoelectric material efficiency and through thermoelectric cooling system thermal design. This research has been focused on the latter one. A prototype thermoelectric cooling system integrated with phase change material (PCM) thermal energy storage unit for space cooling has been developed. The PCM thermal storage unit used for cold storage at night, functions as the thermoelectric cooling system's heat sink during daytime's cooling period and provides relatively lower hot side temperature for the thermoelectric cooling system. The experimental test of the prototype system in a reduced-scale chamber has realized an average cooling COP of 0.87, with the maximum value of 1.22. Another comparison test for efficacy of PCM thermal storage unit shows that 35.3% electrical energy has been saved from using PCM for the thermoelectric cooling system. In general, PCM faces difficulty of poor thermal conductivity at both solid and liquid phases. This system implemented a finned inner tube to increase heat transfer during PCM charging (melting) process that directly impacts thermoelectric system's performance. A simulation tool for the entire system has been developed including mathematical models for a single thermoelectric module

  18. Drought Vulnerability of Thermoelectric Generation using Texas as a Case Study

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  19. Effective thermal conductivity in thermoelectric materials

    SciTech Connect

    Baranowski, LL; Snyder, GJ; Toberer, ES

    2013-05-28

    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" (kappa(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 kappa(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 kappa(eff) predicts the heat fluxes within these devices to 5% of the exact value. (C) 2013 AIP Publishing LLC.

  20. Effective thermal conductivity in thermoelectric materials

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    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" (κeff) 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 κeff 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 κeff predicts the heat fluxes within these devices to 5% of the exact value.

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

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  2. Nanowire Thermoelectric Devices

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

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

    SciTech Connect

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

    2006-10-01

    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.

  4. Room-Temperature Fabrication of a Flexible Thermoelectric Generator Using a Dry-Spray Deposition System

    NASA Astrophysics Data System (ADS)

    Song, Dae-Seob; Choi, Jung-Oh; Ahn, Sung-Hoon

    2016-04-01

    We present a flexible thermoelectric (TE) generator with titanium dioxide (TiO2), antimony (Sb), and tellurium (Te) powders fabricated by a nanoparticle deposition system (NPDS). NPDS is a novel low-energy consumption dry-spray method that enables the deposition of inorganic materials on substrates at room temperature and under low vacuum. TiO2 nanopowders were dispersed on a TE powder for improved adhesion between TE films and the substrate. Film morphologies were investigated using field-emission scanning electron microscopy, and the phase structure was analyzed by x-ray diffraction. A TE leg, deposited with 3 wt.% TiO2 content, had the largest Seebeck coefficient of approximately 160 μV/K. The prototype TE generator consisted of 16 TE legs linked by silver interconnects over an area of 20 mm × 60 mm. The prototype produced a voltage of 48.91 mV and a maximum power output of 0.18 μW from a temperature gradient of 20 K. The values are comparable to that of conventional methods. These results suggest that flexible TE generators can be fabricated by energy efficient methods, although internal and contact resistances must be decreased.

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

    SciTech Connect

    Jifeng Zhang; Jean Yamanis

    2007-09-30

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

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

    PubMed

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

    2013-07-24

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

  9. Power Generation and Peltier Refrigeration by a Tubular π-Type Thermoelectric Module

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    A tubular configuration is a practical form of thermoelectric (TE) device to generate electric power from fluid heat sources as well as to control the temperature of fluid media by Peltier effect. Here, we report the realization of a tubular π-type TE module which enables both power generation and Peltier refrigeration. The tubular module was obtained by stacking ring-shaped constituents in the axial direction, followed by simultaneous spark plasma sintering and joining processes. The experimentally-observed maximum power-density and efficiency are 0.9 kW/m2 and 2.2%, respectively, when a small temperature difference (Δ T) of 85 K was maintained using hot and cold water. Peltier refrigeration of the tube outer surface is also demonstrated. The obtained maximum Δ T and the cooling power density are Δ T = 49 K and 32.6 kW/m2, respectively. The present results indicate the high feasibility of this tube as a fluid-mediated practical TE module.

  10. Refraction-Assisted Solar Thermoelectric Generator based on Phase-Change Lens.

    PubMed

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

    2016-01-01

    Solar thermoelectric generators (STEGs), which are used for various applications, (particularly small size electronic devices), have optical concentration systems for high energy conversion efficiency. In this study, a refraction-assisted STEG (R-STEG) is designed based on phase-change materials. As the phase-change material (PCM) changes phase from solid to liquid, its refractive index and transmittance also change, resulting in changes in the refraction of the sunlight transmitted through it, and concentration of solar energy in the phase-change lens. This innovative design facilitates double focusing the solar energy through the optical lens and a phase-change lens. This mechanism resulted in the peak energy conversion efficiencies of the R-STEG being 60% and 86% higher than those of the typical STEG at solar intensities of 1 kW m(-2) and 1.5 kW m(-2), respectively. In addition, the energy stored in PCM can help to generate steady electrical energy when the solar energy was removed. This work presents significant progress regarding the optical characteristic of PCM and optical concentration systems of STEGs. PMID:27283350

  11. Refraction-Assisted Solar Thermoelectric Generator based on Phase-Change Lens

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    Solar thermoelectric generators (STEGs), which are used for various applications, (particularly small size electronic devices), have optical concentration systems for high energy conversion efficiency. In this study, a refraction-assisted STEG (R-STEG) is designed based on phase-change materials. As the phase-change material (PCM) changes phase from solid to liquid, its refractive index and transmittance also change, resulting in changes in the refraction of the sunlight transmitted through it, and concentration of solar energy in the phase-change lens. This innovative design facilitates double focusing the solar energy through the optical lens and a phase-change lens. This mechanism resulted in the peak energy conversion efficiencies of the R-STEG being 60% and 86% higher than those of the typical STEG at solar intensities of 1 kW m‑2 and 1.5 kW m‑2, respectively. In addition, the energy stored in PCM can help to generate steady electrical energy when the solar energy was removed. This work presents significant progress regarding the optical characteristic of PCM and optical concentration systems of STEGs.

  12. Refraction-Assisted Solar Thermoelectric Generator based on Phase-Change Lens

    PubMed Central

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

    2016-01-01

    Solar thermoelectric generators (STEGs), which are used for various applications, (particularly small size electronic devices), have optical concentration systems for high energy conversion efficiency. In this study, a refraction-assisted STEG (R-STEG) is designed based on phase-change materials. As the phase-change material (PCM) changes phase from solid to liquid, its refractive index and transmittance also change, resulting in changes in the refraction of the sunlight transmitted through it, and concentration of solar energy in the phase-change lens. This innovative design facilitates double focusing the solar energy through the optical lens and a phase-change lens. This mechanism resulted in the peak energy conversion efficiencies of the R-STEG being 60% and 86% higher than those of the typical STEG at solar intensities of 1 kW m−2 and 1.5 kW m−2, respectively. In addition, the energy stored in PCM can help to generate steady electrical energy when the solar energy was removed. This work presents significant progress regarding the optical characteristic of PCM and optical concentration systems of STEGs. PMID:27283350

  13. Near-term thermoelectric nuclear power options for SEI missions

    NASA Technical Reports Server (NTRS)

    Peterson, Jerry R.

    1992-01-01

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

  14. Disposition of Radioisotope Thermoelectric Generators Currently Located at the Oak Ridge National Laboratory - 12232

    SciTech Connect

    Glenn, J.; Patterson, J.; DeRoos, K.; Patterson, J.E.; Mitchell, K.G.

    2012-07-01

    Under the American Recovery and Reinvestment Act (ARRA), the U.S. Department of Energy (DOE) awarded SEC Federal Services Corporation (SEC) a 34-building demolition and disposal (D and D) project at the Oak Ridge National Laboratory (ORNL) that included the disposition of six Strontium (Sr-90) powered Radioisotope Thermoelectric Generators (RTGs) stored outside of ORNL Building 3517. Disposition of the RTGs is very complex both in terms of complying with disposal facility waste acceptance criteria (WAC) and U.S. Department of Transportation (DOT) requirements for packaging and transportation in commerce. Two of the RTGs contain elemental mercury which requires them to be Land Disposal Restrictions (LDR) compliant prior to disposal. In addition, all of the RTGs exceed the Class C waste concentration limits under Nuclear Regulatory Commission (NRC) Waste Classification Guidelines. In order to meet the LDR requirements and Nevada National Security Site (NNSS) WAC, a site specific treatability variance for mercury was submitted to the U.S. Environmental Protection Agency (EPA) to allow macro-encapsulation to be an acceptable treatment standard for elemental mercury. By identifying and confirming the design configuration of the mercury containing RTGs, the SEC team proved that the current configuration met the macro-encapsulation standard of 40 Code of Federal Regulations (CFR) 268.45. The SEC Team also worked with NNSS to demonstrate that all radioisotope considerations are compliant with the NNSS low-level waste (LLW) disposal facility performance assessment and WAC. Lastly, the SEC team determined that the GE2000 Type B cask met the necessary size, weight, and thermal loading requirements for five of the six RTGs. The sixth RTG (BUP-500) required a one-time DOT shipment exemption request due to the RTG's large size. The DOT exemption justification for the BUP-500 relies on the inherent robust construction and material make-up of the BUP- 500 RTG. DOE-ORO, SEC, and

  15. A shielded storage and processing facility for radioisotope thermoelectric generator heat source production

    NASA Astrophysics Data System (ADS)

    Sherrell, Dennis L.

    1993-01-01

    A shielded storage rack has been installed as part of the Radioisotope Power Systems Facility (RPSF) at the U.S. Department of Energy's (DOE) Hanford Site in Washington State. The RPSF is designed to replace an existing facility at DOE's Mound Site near Dayton, Ohio, where General Purpose Heat Source (GPHS) modules are currently assembled and installed into Radioisotope Thermoelectric Generators (RTG). The overall design goal of the RPSF is to increase annual production throughput, while at the same time reducing annual radiation exposure to personnel. The shield rack design successfully achieved this goal for the Module Reduction and Monitoring Facility (MRMF), which processes and stores assembled GPHS modules, prior to their installation into RTGs. The shield rack design is simple and effective, with the result that background radiation levels within Hanford's MRMF room are calculated at just over three percent of those typically experienced during operation of the existing MRMF at Mound, despite the fact that Hanford's calculations assume five times the GPHS inventory of that assumed for Mound.

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

    NASA Astrophysics Data System (ADS)

    Nejat, Cyrus; Nejat, Narsis; Nejat, Najmeh

    2014-06-01

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

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

    PubMed

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

    2012-03-01

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

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

    SciTech Connect

    Lockwood, A.; Shields, V.

    1980-07-01

    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.

  19. Simulation and Optimization of the Heat Exchanger for Automotive Exhaust-Based Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    Su, C. Q.; Huang, C.; Deng, Y. D.; Wang, Y. P.; Chu, P. Q.; Zheng, S. J.

    2016-03-01

    In order to enhance the exhaust waste heat recovery efficiency of the automotive exhaust-based thermoelectric generator (TEG) system, a three-segment heat exchanger with folded-shaped internal structure for the TEG system is investigated in this study. As the major effect factors of the performance for the TEG system, surface temperature, and thermal uniformity of the heat exchanger are analyzed in this research, pressure drop along the heat exchanger is also considered. Based on computational fluid dynamics simulations and temperature distribution, the pressure drop along the heat exchanger is obtained. By considering variable length and thickness of folded plates in each segment of the heat exchanger, response surface methodology and optimization by a multi-objective genetic algorithm is applied for surface temperature, thermal uniformity, and pressure drop for the folded-shaped heat exchanger. An optimum design based on the optimization is proposed to improve the overall performance of the TEG system. The performance of the optimized heat exchanger in different engine conditions is discussed.

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

    SciTech Connect

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

    1990-04-19

    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.

  1. A shielded storage and processing facility for radioisotope thermoelectric generator heat source production

    SciTech Connect

    Sherrell, D.L.

    1992-06-01

    This report discusses a shielded storage rack which has been installed as part of the Radioisotope Power Systems Facility (RPSF) at the US Department of Energy's (DOE) Hanford Site in Washington State. The RPSF is designed to replace an existing facility at DOE's Mound Site near Dayton, Ohio, where General Purpose Heat Source (GPHS) modules are currently assembled and installed into Radioisotope Thermoelectric Generators (RTG). The overall design goal of the RPSF is to increase annual production throughput, while at the same time reducing annual radiation exposure to personnel. The shield rack design successfully achieved this goal for the Module Reduction and Monitoring Facility (MRMF), which process and stores assembled GPHS modules, prior to their installation into RTGS. The shield rack design is simple and effective, with the result that background radiation levels within Hanford's MRMF room are calculated at just over three percent of those typically experienced during operation of the existing MRMF at Mound, despite the fact that Hanford's calculations assume five times the GPHS inventory of that assumed for Mound.

  2. A shielded storage and processing facility for radioisotope thermoelectric generator heat source production

    SciTech Connect

    Sherrell, D.L.

    1992-06-01

    This report discusses a shielded storage rack which has been installed as part of the Radioisotope Power Systems Facility (RPSF) at the US Department of Energy`s (DOE) Hanford Site in Washington State. The RPSF is designed to replace an existing facility at DOE`s Mound Site near Dayton, Ohio, where General Purpose Heat Source (GPHS) modules are currently assembled and installed into Radioisotope Thermoelectric Generators (RTG). The overall design goal of the RPSF is to increase annual production throughput, while at the same time reducing annual radiation exposure to personnel. The shield rack design successfully achieved this goal for the Module Reduction and Monitoring Facility (MRMF), which process and stores assembled GPHS modules, prior to their installation into RTGS. The shield rack design is simple and effective, with the result that background radiation levels within Hanford`s MRMF room are calculated at just over three percent of those typically experienced during operation of the existing MRMF at Mound, despite the fact that Hanford`s calculations assume five times the GPHS inventory of that assumed for Mound.

  3. Multi-Objective Optimization Design for Cooling Unit of Automotive Exhaust-Based Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    Qiang, J. W.; Yu, C. G.; Deng, Y. D.; Su, C. Q.; Wang, Y. P.; Yuan, X. H.

    2016-03-01

    In order to improve the performance of cooling units for automotive thermoelectric generators, a study is carried out to optimize the cold side and the fin distributions arranged on its inner faces. Based on the experimental measurements and numerical simulations, a response surface model of different internal structures is built to analyze the heat transfer and pressure drop characteristics of fluid flow in the cooling unit. For the fin distributions, five independent variables including height, length, thickness, space and distance from walls are considered. An experimental study design incorporating the central composite design method is used to assess the influence of fin distributions on the temperature field and the pressure drop in the cooling units. The archive-based micro genetic algorithm (AMGA) is used for multi-objective optimization to analyze the sensitivity of the design variables and to build a database from which to construct the surrogate model. Finally, improvement measures are proposed for optimization of the cooling system and guidelines are provided for future research.

  4. Operational Readiness Review Plan for the Radioisotope Thermoelectric Generator Materials Production Tasks

    DOE R&D Accomplishments Database

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

    1990-04-19

    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.

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

    SciTech Connect

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

    1992-01-01

    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.

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

    SciTech Connect

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

    1992-12-31

    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.

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

    NASA Astrophysics Data System (ADS)

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

    1996-10-01

    Thermoelectric devices are solid-state devices that convert thermal energy from a temperature gradient into electrical energy (the Seebeck effect) or convert electrical energy into a temperature gradient (the Peltier effect). The first application is used most notably in spacecraft power generation systems (for example, in Voyager I and II) and in thermocouples for temperature measurement, while the second application is largely used in specialized cooling applications. Both applications can be demonstrated in the lecture hall to illustrate thermodynamic principles in a compelling manner. They also provide insight into the workings of a high-tech system that is achieving more widespread consumer use. The most visible consumer use of thermoelectric devices utilizing the Peltier effect is in portable electric food coolers/warmers that plug into an automobile cigarette lighter. Conventional cooling systems such as those used in refrigerators utilize a compressor and a working fluid to transfer heat. Thermal energy is absorbed and released as the working fluid undergoes expansion and compression and changes phase from liquid to vapor and back, respectively (1). Semiconductor thermoelectric coolers (also known as Peltier coolers) offer several advantages over conventional systems. They are entirely solid-state devices, with no moving parts; this makes them rugged, reliable, and quiet. They use no ozone-depleting chlorofluorocarbons, potentially offering a more environmentally responsible alternative to conventional refrigeration. They can be extremely compact, much more so than compressor-based systems. Precise temperature control (< ±0.1 °C) can be achieved with Peltier coolers. However, their efficiency is low compared to conventional refrigerators. Thus, they are used in niche applications where their unique advantages outweigh their low efficiency. Although some large-scale applications have been considered (on submarines and surface vessels), Peltier coolers are

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    This paper presents a thermoelectric (TE) generator and a solid-state battery for powering microsystems. Prototypes of TE generators were fabricated and characterized. The TE generator is a planar microstructure based on thin films of n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3), which were deposited using co-evaporation. The measurements on selected samples of Bi2Te3 and Sb2Te3 thin films indicated a Seebeck coefficient in the range of 90-250 µV K-1 and an in-plane electrical resistivity in the range of 7-17 µΩ m. The measurements also showed TE figures-of-merit, ZT, at room temperatures (T = 300 K) of 0.97 and 0.56, for thin films of Bi2Te3 and Sb2Te3, respectively (equivalent to a power factor, PF, of 4.87 mW K-2 m-1 and 2.81 mW K-2 m-1). The solid-state battery is based on thin films of: an anode of tin dioxide (SnO2), an electrolyte of lithium phosphorus oxynitride (LixPOyNz, known as LiPON) and a cathode of lithium cobaltate (LiCoO2, known as LiCO), which were deposited using the reactive RF (radio-frequency) sputtering. The deposition and characterization results of these thin-films layers are also reported in this paper.

  10. Development of a portable power system with meso-scale vortex combustor and thermo-electric device

    NASA Astrophysics Data System (ADS)

    Shimokuri, D.; Hara, T.; Ishizuka, S.

    2014-11-01

    In this study, a small scale power generation system with a meso-scale vortex combustor has been developed. The system was consisted of a couple of thermo-electric device and a heat medium. The medium was made of duralumin, 40 × 40 × 20 mm and 52 g weight, and the vortex combustion chamber of 7 mm inner diameter was embedded in it. It was found that a stable flame could be established in the narrow 7 mm channel even the mean axial velocity reached 1.2 m/s. And furthermore, the vortex flow significantly enhanced the heat transfer from the burned gas to combustion chamber, and as a result, the medium was heated to 300°C quickly (within 5 minutes) by the combustion of propane / air mixture for 145W input energy. The system could successfully generate 1.98 W (4.3 V and 0.46 A), which corresponded to the energy conversion rate of 0.7 % per unit thermo-electric device.

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

    PubMed Central

    Li, Sheng; Yao, Xinhua; Fu, Jianzhong

    2014-01-01

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

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

    PubMed

    Li, Sheng; Yao, Xinhua; Fu, Jianzhong

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  14. Transient thermoelectric supercooling: Isosceles current pulses from a response surface perspective and the performance effects of pulse cooling a heat generating mass

    NASA Astrophysics Data System (ADS)

    Piggott, Alfred J., III

    With increased public interest in protecting the environment, scientists and engineers aim to improve energy conversion efficiency. Thermoelectrics offer many advantages as thermal management technology. When compared to vapor compression refrigeration, above approximately 200 to 600 watts, cost in dollars per watt as well as COP are not advantageous for thermoelectrics. The goal of this work was to determine if optimized pulse supercooling operation could improve cooling capacity or efficiency of a thermoelectric device. The basis of this research is a thermal-electrical analogy based modeling study using SPICE. Two models were developed. The first model, a standalone thermocouple with no attached mass to be cooled. The second, a system that includes a module attached to a heat generating mass. With the thermocouple study, a new approach of generating response surfaces with characteristic parameters was applied. The current pulse height and pulse on-time was identified for maximizing Net Transient Advantage, a newly defined metric. The corresponding pulse height and pulse on-time was utilized for the system model. Along with the traditional steady state starting current of Imax, Iopt was employed. The pulse shape was an isosceles triangle. For the system model, metrics new to pulse cooling were Qc, power consumption and COP. The effects of optimized current pulses were studied by changing system variables. Further studies explored time spacing between pulses and temperature distribution in the thermoelement. It was found net Q c over an entire pulse event can be improved over Imax steady operation but not over steady I opt operation. Qc can be improved over Iopt operation but only during the early part of the pulse event. COP is reduced in transient pulse operation due to the different time constants of Qc and Pin. In some cases lower performance interface materials allow more Qc and better COP during transient operation than higher performance interface materials

  15. Optimal design of an atmospheric water generator (AWG) based on thermo-electric cooler (TEC) for drought in rural area

    NASA Astrophysics Data System (ADS)

    Suryaningsih, Sri; Nurhilal, Otong

    2016-02-01

    Drinking water availability is a major issue in some rural area in Indonesia during the summer season due to lack of rainfall, which peoples in this area have to fetch the water a few kilometers away from home. The Atmospheric Water Generator (AWG) is one of the alternative solution for fresh water recovery from atmosphere which is directly condensed the moisture content of water vapor from the air. This paper presents the method to develop a prototype of an AWG based on Thermo-electric cooler (TEC) that used 12 Volt DC, hence its suitability for using renewable energy resource. Computational Fluid Dynamics (CFD) is utilized to optimize the design process in the flow region only, it's not suitable for recent CFD software to use in Multi physics, because inaccuracy, cost and time saving. Some parameters such as temperature, moisture content, air flow, pressure, form of air flow channel and the water productivity per unit input of energy are to be considered. The result is presented as an experimental prototype of an AWG based on TEC and compared with other conventional commercial products.

  16. POTENTIAL THERMOELECTRIC APPLICATIONS IN DIESEL VEHICLES

    SciTech Connect

    Crane, D

    2003-08-24

    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.

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

    SciTech Connect

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

    1996-10-01

    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.

  18. Thermoelectric generators from SiO2/SiO2 + Ge nanolayer thin films modified by MeV Si ions

    NASA Astrophysics Data System (ADS)

    Budak, S.; Gulduren, E.; Allen, B.; Cole, J.; Lassiter, J.; Colon, T.; Muntele, C.; Alim, M. A.; Bhattacharjee, S.; Johnson, R. B.

    2015-01-01

    We prepared thermoelectric generator devices from 100 alternating layers of SiO2/SiO2 + Ge superlattice thin films using Magnetron DC/RF Sputtering. Rutherford Backscattering Spectrometry (RBS) and RUMP simulation software package were used to determine the proportions of Si and Ge in the grown multilayer films and the thickness of the grown multi-layer films. 5 MeV Si ion bombardments were performed using the AAMU-Pelletron ion beam accelerator, to form quantum clusters in the multi-layer superlattice thin films, in order to tailor the thermoelectrical and optical properties. We characterized the fabricated thermoelectric devices using cross-plane Seebeck coefficient, van der Pauw resistivity, mobility, density (carrier concentration), Hall Effect coefficient, Raman, Fluorescence, Photoluminescence, Atomic Force Microscopy (AFM) and Impedance analyzing measurements. Some suitable high energy ion fluences and thermal annealings caused some remarkable thermoelectrical and optical changes in the fabricated multilayer thin film systems.

  19. Optimization of Fin Distribution to Improve the Temperature Uniformity of a Heat Exchanger in a Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Wang, Yiping; Wu, Cheng; Tang, Zebo; Yang, Xue; Deng, Yadong; Su, Chuqi

    2015-06-01

    Thermoelectric generators (TEGs) are currently a topic of interest for energy recovery in vehicles. By applying TEGs to the outside surface of the exhaust tailpipe, a small amount of electrical power can be generated because of the temperature difference between the hot exhaust gases and the automobile coolant. The amount of power is anticipated to be a few hundred watts based on the expected temperature difference and the properties of the thermoelectric materials used in TEGs. It is well know that, for thermoelectric exhaust energy recovery, the temperature uniformity of the heat exchangers has a strong influence on the electric power generation. In the current research, the temperature uniformity of a heat exchanger was improved by optimizing the fin distribution to maximize the electric power generated for a given vehicle TEG. A computational fluid dynamics (CFD) model of the heat exchanger was constructed to assess the influence of different fin distributions on the temperature uniformity and the pressure drop in the exhaust system. For the fin distributions, four factors were considered: the length of, spacing between, angle of, and thickness of the fins. Based on these four factors, a design of experiments study using the orthogonal experimental method was conducted to analyze the sensitivity to the design variables and build a database to set up a surrogate model using the Kriging response surface method. A multi-island genetic algorithm was used to optimize the fin distribution based on this surrogate model. To validate the accuracy of the CFD model, a generic heat exchanger module was manufactured and a related testbed constructed, then the temperature distribution on the surface of the exchanger was measured to compare with the results obtained by CFD.

  20. Research In Thermoelectric Materials

    NASA Technical Reports Server (NTRS)

    Wood, Charles

    1989-01-01

    Report reviews current research in thermoelectric materials with view towards development of materials of greater energy-conversion efficiency. Emphasis on effort to understand and manipulate microstructure to increase thermoelectric figure of merit, Z. Thermoelectric properties of three broad categories of materials discussed. First category includes alloys of group IV elements like silicon and germanium. Second category is rare-earth chalcogenides. Third category includes narrow-band semiconductors, especially boron carbides.

  1. Resolving thermoelectric “paradox” in superconductors

    PubMed Central

    Shelly, Connor D.; Matrozova, Ekaterina A.; Petrashov, Victor T.

    2016-01-01

    For almost a century, thermoelectricity in superconductors has been one of the most intriguing topics in physics. During its early stages in the 1920s, the mere existence of thermoelectric effects in superconductors was questioned. In 1944, it was demonstrated that the effects may occur in inhomogeneous superconductors. Theoretical breakthrough followed in the 1970s, when the generation of a measurable thermoelectric magnetic flux in superconducting loops was predicted; however, a major crisis developed when experiments showed puzzling discrepancies with the theory. Moreover, different experiments were inconsistent with each other. This led to a stalemate in bringing theory and experiment into agreement. With this work, we resolve this stalemate, thus solving this long-standing “paradox,” and open prospects for exploration of novel thermoelectric phenomena predicted recently. PMID:26933688

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

    SciTech Connect

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

    1984-06-26

    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.

  3. A New High Efficiency Segmented Thermoelectric Unicouple

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    To achieve high thermal-to-electric energy conversion efficiency, it is desirable to operate thermoelectric generator devices over large temperature gradients and also to maximize the thermoelectric performance of the materials used to build the devices. However, no single thermoelectric material is suitable for use over a very wide range of temperatures (approx. 300 - 1000 K). It is therefore necessary to use different materials in each temperature range where they possess optimum performance. This can be achieved in two ways: 1) multistage thermoelectric generators where each stage operates over a fixed temperature difference and is electrically insulated but thermally in contact with the other stages and 2) segmented generators where the p- and n-legs are formed of different segments joined in series. The concept of integrating new thermoelectric materials developed at the Jet Propulsion Laboratory (JPL) into a segmented thermoelectric generator has been presented in detail in earlier publications . This new generator is expected to operate over a 300-973 K temperature difference and will use novel segmented legs based on a combination of state-of-the-art thermoelectric materials and novel p-type Zn4Sb3, p-type CeFe4Sb12-based alloys and n-type CoSb3-based alloys. An increase in the conversion efficiency of about 60% is expected compared to conventional Bi2Te3- and PbTe-based generators. We present in this paper the latest experimental results from the bonding studies between the different segments of the p-legs, n-legs, and p-leg to n-leg interconnect. Evaluation of the bond quality was done by measuring the contact resistance across the joints as well as by detailed microstructure investigations to reveal any potential interdiffusion. Among the materials investigated as inter-layers between the different segments of the legs, Pd-Ag joining alloys have been found to provide mechanically stable and low electrical resistance bonds.

  4. Thermoelectric converter

    DOEpatents

    Kim, C.K.

    1974-02-26

    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)

  5. Laboratory development TPV generator

    SciTech Connect

    Holmquist, G.A.; Wong, E.M.; Waldman, C.H.

    1996-02-01

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

  6. Third generation infrared system calibration using dual band thermoelectric thermal reference sources and test systems to calibrate uncooled IRFPAs

    NASA Astrophysics Data System (ADS)

    Finfrock, David K.; Kolander, William L.

    2008-04-01

    As dual band, 3rd generation FLIR systems progress from the research lab into the field, supporting technologies must also advance. This paper describes advances in Thermoelectric Thermal Reference Sources (TTRS) from single band (3 to 5 or 8 to 12 microns) to dual band in one assembly (3 to 5 and 8 to 12 microns). It will describe the optical, system, electrical, and mechanical parameters of dual band TTRS units. It provides IR system design engineers with the critical parameters of dual band TTRS units to aid in their design process. TTRS assemblies provide a temperature controllable radiometrically uniform surface. When viewed by theFLIR system detectors, the TTRS enables the system electronics to perform gain and offset calibration as well as DC restoration for each pixel's preamp Some of the parameters for 3rd Generation FLIR system TTRS units included in this paper will be: Emissivity of BB surfaces. Apparent thermal radiometric uniformity. How this is predicted and measured. Window material wavelength transmission (Hermetically sealed units only). TTRS emitter surface temperatures as a function of heat sink temperatures. Trade-off between uniformity, power consumption, and transient performance. Power consumption, Thermal interfaces and required heat sinking Types and accuracy of Temperature sensors mounted on emitter surface. Also included in this paper is a description of a Thermoelectric Black Body Test Apparatus that can be used to generate temperature coefficients needed to "burn" Proms for uncooled IRFPAs during their production and burn in processing.

  7. High Efficiency Thermoelectric Materials and Devices

    NASA Technical Reports Server (NTRS)

    Kochergin, Vladimir (Inventor)

    2013-01-01

    Growth of thermoelectric materials in the form of quantum well super-lattices on three-dimensionally structured substrates provide the means to achieve high conversion efficiency of the thermoelectric module combined with inexpensiveness of fabrication and compatibility with large scale production. Thermoelectric devices utilizing thermoelectric materials in the form of quantum well semiconductor super-lattices grown on three-dimensionally structured substrates provide improved thermoelectric characteristics that can be used for power generation, cooling and other applications..

  8. Achieving Maximum Power from Thermoelectric Generators with Maximum-Power-Point-Tracking Circuits Composed of a Boost-Cascaded-with-Buck Converter

    NASA Astrophysics Data System (ADS)

    Park, Hyunbin; Sim, Minseob; Kim, Shiho

    2015-06-01

    We propose a way of achieving maximum power and power-transfer efficiency from thermoelectric generators by optimized selection of maximum-power-point-tracking (MPPT) circuits composed of a boost-cascaded-with-buck converter. We investigated the effect of switch resistance on the MPPT performance of thermoelectric generators. The on-resistances of the switches affect the decrease in the conversion gain and reduce the maximum output power obtainable. Although the incremental values of the switch resistances are small, the resulting difference in the maximum duty ratio between the input and output powers is significant. For an MPPT controller composed of a boost converter with a practical nonideal switch, we need to monitor the output power instead of the input power to track the maximum power point of the thermoelectric generator. We provide a design strategy for MPPT controllers by considering the compromise in which a decrease in switch resistance causes an increase in the parasitic capacitance of the switch.

  9. n-type thermoelectric material Mg2Sn0.75Ge0.25 for high power generation

    PubMed Central

    Liu, Weishu; Kim, Hee Seok; Chen, Shuo; Jie, Qing; Lv, Bing; Yao, Mengliang; Ren, Zhensong; Opeil, Cyril P.; Wilson, Stephen; Chu, Ching-Wu; Ren, Zhifeng

    2015-01-01

    Thermoelectric power generation is one of the most promising techniques to use the huge amount of waste heat and solar energy. Traditionally, high thermoelectric figure-of-merit, ZT, has been the only parameter pursued for high conversion efficiency. Here, we emphasize that a high power factor (PF) is equivalently important for high power generation, in addition to high efficiency. A new n-type Mg2Sn-based material, Mg2Sn0.75Ge0.25, is a good example to meet the dual requirements in efficiency and output power. It was found that Mg2Sn0.75Ge0.25 has an average ZT of 0.9 and PF of 52 μW⋅cm−1⋅K−2 over the temperature range of 25–450 °C, a peak ZT of 1.4 at 450 °C, and peak PF of 55 μW⋅cm−1⋅K−2 at 350 °C. By using the energy balance of one-dimensional heat flow equation, leg efficiency and output power were calculated with Th = 400 °C and Tc = 50 °C to be of 10.5% and 6.6 W⋅cm−2 under a temperature gradient of 150 °C⋅mm−1, respectively. PMID:25733845

  10. New Composite Thermoelectric Materials for Macro-size Applications

    ScienceCinema

    Dresselhaus, Mildred [MIT, Cambridge, Massachusetts, United States

    2010-01-08

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

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

    SciTech Connect

    Felicione, Frank S.

    2009-12-01

    Mass properties (MP) measurements were performed for the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), serial number (S/N) 0X730401, the power system designated for the Mars Science Laboratory (MSL) mission. Measurements were made using new mounting fixtures at the mass properties testing station in the Idaho National Laboratory (INL) Space and Security Power Systems Facility (SSPSF). The objective of making mass properties measurements was to determine the generator’s flight configured mass and center of mass or center of gravity (CG). Using an extremely accurate platform scale, the mass of the as-tested generator was determined to be 100.117 ± 0.007 lb. Weight accuracy was determined by checking the platform scale with calibrated weights immediately prior to weighing the MMRTG.a CG measurement accuracy was assessed by surrogate testing using an inert mass standard for which the CG could be readily determined analytically. Repeated testing using the mass standard enabled the basic measurement precision of the system to be quantified in terms of a physical confidence interval about the measured CG position. However, repetitious testing with the MMRTG itself was not performed in deference to the gamma and neutron radiation dose to operators and the damage potential to the flight unit from extra handling operations. Since the mass standard had been specially designed to have a total weight and CG location that closely matched the MMRTG, the uncertainties determined from its testing were assigned to the MMRTG as well. On this basis, and at the 99% confidence level, a statistical analysis found the direct, as-measured MMRTG-MSL CG to be located at 10.816 ± 0.0011 in. measured perpendicular from the plane of the lower surface of the generator’s mounting lugs (Z direction), and offset from the generator’s long axis centerline in the X and Y directions by 0.0968 ± 0.0040 in. and 0.0276 ± 0.0026 in., respectively. These uncertainties are based

  12. Solution synthesis of telluride-based nano-barbell structures coated with PEDOT:PSS for spray-printed thermoelectric generators

    NASA Astrophysics Data System (ADS)

    Bae, Eun Jin; Kang, Young Hun; Jang, Kwang-Suk; Lee, Changjin; Cho, Song Yun

    2016-05-01

    Solution-processable telluride-based heterostructures coated with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (Te-Bi2Te3/PEDOT:PSS) were synthesized through a solution-phase reaction at low temperatures. The water-based synthesis yielded PEDOT:PSS-coated Te-Bi2Te3 nano-barbell structures with a high Seebeck coefficient that can be stably dispersed in water. These hybrid solutions were deposited onto a substrate by the spray-printing method to prepare thermoelectric generators. The thermoelectric properties of the Te-Bi2Te3/PEDOT:PSS hybrid films were significantly enhanced by a simple acid treatment due to the increased electrical conductivity, and the power factor of those materials can be effectively tuned over a wide range depending on the acid concentration of the treatment. The power factors of the synthesized Te-Bi2Te3/PEDOT:PSS hybrids were optimized to 60.05 μW m-1 K-2 with a Seebeck coefficient of 93.63 μV K-1 and an electrical conductivity of 69.99 S cm-1. The flexible thermoelectric generator fabricated by spray-printing Te-Bi2Te3/PEDOT:PSS hybrid solutions showed an open-circuit voltage of 1.54 mV with six legs at ΔT = 10 °C. This approach presents the potential for realizing printing-processable hybrid thermoelectric materials for application in flexible thermoelectric generators.Solution-processable telluride-based heterostructures coated with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (Te-Bi2Te3/PEDOT:PSS) were synthesized through a solution-phase reaction at low temperatures. The water-based synthesis yielded PEDOT:PSS-coated Te-Bi2Te3 nano-barbell structures with a high Seebeck coefficient that can be stably dispersed in water. These hybrid solutions were deposited onto a substrate by the spray-printing method to prepare thermoelectric generators. The thermoelectric properties of the Te-Bi2Te3/PEDOT:PSS hybrid films were significantly enhanced by a simple acid treatment due to the increased electrical conductivity, and

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

    NASA Astrophysics Data System (ADS)

    Hutson, S.

    2013-12-01

    The U.S Geological Survey (USGS) has estimated thermoelectric water withdrawals at 5-year intervals since 1950, and consumptive use from 1950 to 1995. Changes in water demand for cooling water, a significant part of the thermoelectric water use, has important implications for water availability to meet future energy demand, especially at the local level. USGS data show total water withdrawals peaked in 1980, declined in 1985, and have remained relatively stable through 2005. Total water use has been dominated by thermoelectric withdrawals since 1965. USGS estimates through 2005 have been primarily based on compiling self-reported data by powerplant operators to State water regulatory agencies and to the Department of Energy-Energy Information Administration (EIA). The reported data from these sources have often been inconsistent because techniques for measuring or estimating the main water flows are not standardized; and, incomplete because reporting thresholds for water withdrawals vary from State-to-State. EIA only requires the reporting of water use from powerplants that are 100 megawatts or more. Some withdrawals have also been estimated with a gallon per kilowatt-hour coefficient and powerplant net electric generation; however, coefficients were mostly based on reported data, and although the coefficients accounted for differences in cooling systems, fuel type, and flue gas desulfurization and other factors, the coefficients are averages and have not accounted for either weather or climatic conditions. The USGS National Water Use Information Program (NWUIP) developed consistent estimates of water withdrawals and water consumption based on linked heat and water budgets for the entire fleet of 1,284 active water-using powerplants for 2010. In 2010, 802 powerplants reported water-use data to EIA. The linked heat and water budget calculates condenser duty for a powerplant, and estimated water withdrawal is a function of condenser duty and change in temperature in

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  15. Research on Integration of an Automotive Exhaust-Based Thermoelectric Generator and a Three-Way Catalytic Converter

    NASA Astrophysics Data System (ADS)

    Deng, Y. D.; Chen, Y. L.; Chen, S.; Xianyu, W. D.; Su, C. Q.

    2015-06-01

    A key research topic related to thermoelectric generators (TEGs) for automotive applications is to improve their compatibility with the original vehicle exhaust system, which determines the quality of the exhaust gas treatment and the realization of energy conservation and emission reduction. A new TEG integrated with a three-way catalytic converter (CTEG) by reshaping the converter as the heat exchanger is proposed. A heat-flux coupling simulation model of the integrated TEG is established at the light-off stage of the original three-way catalytic converter (TWC). Temperature distribution maps of the integrated heat exchanger, thermoelectric modules, and cooling-water tank are obtained to present the process of energy flow among the parts of the CTEG. Based on the simulation results, the output power of the CTEG is calculated by a mathematical model. A minimum output power of 31.93 W can be obtained by conversion when the TWC starts working at steady conditions. Theoretically, this case study demonstrates the great potential for use of CTEGs in vehicles.

  16. High Temperature Integrated Thermoelectric Ststem and Materials

    SciTech Connect

    Mike S. H. Chu

    2011-06-06

    . 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.

  17. Thermoelectric Outer Planets Spacecraft (TOPS)

    NASA Technical Reports Server (NTRS)

    1973-01-01

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

  18. The design of Cu-doped ZnO thermoelectric module (simulation study)

    NASA Astrophysics Data System (ADS)

    Hadi, Syamsul; Suratwan, Agus; Kurniawan, Agus; Budiana, Eko Prasetya; Suyitno

    2016-03-01

    The p-type semiconductor of Cu-doped ZnO-based thermoelectric material has already been synthesized and studied as an energy harvester. The next challenge is manufacturing the thermoelectric module in the development of thermoelectric as an eco-friendly material in the future. This research aims to investigate the effect of thermoelectric geometric design on the electrical output power and voltage and to recommend the most appropriate thermoelectric geometric design. The design of thermoelectric generator (TEG) includes the determinations of dimension (width, length, and height), number of modules, and semiconductor materials. The simulation used the coupled-field analysis of ANSYS APDL 14.5 in the steady state condition. The p- and n- type thermoelectric material used Cu-doped ZnO and Al-doped ZnO, respectively. The width of element and the number of thermoelectric module were varied to obtain a thermoelectric design, which produces the largest current, power, and voltage. The result of research shows that the t hermoelectric generator with the element widths of 0.94 mm, 1.125 mm, 1.05 mm, and 1.2 mm generates the largest power output and voltage, namely: 0.32 W and 0.89 V, 0.38 W and 0.98 V, 0.45 W and 1.06 V, and 0.52 W and 1.13 V, respectively.

  19. Thermal Cycling Behavior of Zinc Antimonide Thin Films for High Temperature Thermoelectric Power Generation Applications.

    PubMed

    Shim, Hyung Cheoul; Woo, Chang-Su; Han, Seungwoo

    2015-08-19

    The zinc antimonide compound ZnxSby is one of the most efficient thermoelectric materials known at high temperatures due to its exceptional low thermal conductivity. For this reason, it continues to be the focus of active research, especially regarding its glass-like atomic structure. However, before practical use in actual surroundings, such as near a vehicle manifold, it is imperative to analyze the thermal reliability of these materials. Herein, we present the thermal cycling behavior of ZnxSby thin films in nitrogen (N2) purged or ambient atmosphere. ZnxSby thin films were prepared by cosputtering and reached a power factor of 1.39 mW m(-1) K(-2) at 321 °C. We found maximum power factor values gradually decreased in N2 atmosphere due to increasing resistivity with repeated cycling, whereas the specimen in air kept its performance. X-ray diffraction and electron microscopy observations revealed that fluidity of Zn atoms leads to nanoprecipitates, porous morphologies, and even growth of a coating layer or fiber structures on the surface of ZnxSby after repetitive heating and cooling cycles. With this in mind, our results indicate that proper encapsulation of the ZnxSby surface would reduce these unwanted side reactions and the resulting degradation of thermoelectric performance. PMID:26226167

  20. Thermal Test of an Improved Platform for Silicon Nanowire-Based Thermoelectric Micro-generators

    NASA Astrophysics Data System (ADS)

    Calaza, C.; Fonseca, L.; Salleras, M.; Donmez, I.; Tarancón, A.; Morata, A.; Santos, J. D.; Gadea, G.

    2016-03-01

    This work reports on an improved design intended to enhance the thermal isolation between the hot and cold parts of a silicon-based thermoelectric microgenerator. Micromachining techniques and silicon on insulator substrates are used to obtain a suspended silicon platform surrounded by a bulk silicon rim, in which arrays of bottom-up silicon nanowires are integrated later on to join both parts with a thermoelectric active material. In previous designs the platform was linked to the rim by means of bulk silicon bridges, used as mechanical support and holder for the electrical connections. Such supports severely reduce platform thermal isolation and penalise the functional area due to the need of longer supports. A new technological route is planned to obtain low thermal conductance supports, making use of a particular geometrical design and a wet bulk micromachining process to selectively remove silicon shaping a thin dielectric membrane. Thermal conductance measurements have been performed to analyse the influence of the different design parameters of the suspended platform (support type, bridge/membrane length, separation between platform and silicon rim,) on overall thermal isolation. A thermal conductance reduction from 1.82 mW/K to 1.03 mW/K, has been obtained on tested devices by changing the support type, even though its length has been halved.

  1. Determination of Thermoelectric Module Efficiency A Survey

    SciTech Connect

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

    2014-01-01

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

  2. Printable thermoelectric devices and conductive patterns for medical applications

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

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

    PubMed

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

    2014-10-29

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    NASA Technical Reports Server (NTRS)

    Stapfer, G.; Truscello, V. C.

    1975-01-01

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

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

    SciTech Connect

    2012-01-31

    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.

  7. Thermoelectric harvesting of low temperature natural/waste heat

    NASA Astrophysics Data System (ADS)

    Rowe, David Michael

    2012-06-01

    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.

  8. Long term thermoelectric module testing system.

    PubMed

    D'Angelo, Jonathan; Hogan, Timothy

    2009-10-01

    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. PMID:19895086

  9. Advanced Thermoelectric Materials for Efficient Waste Heat Recovery in Process Industries

    SciTech Connect

    Adam Polcyn; Moe Khaleel

    2009-01-06

    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.

  10. Thermoelectric Power-Generation Characteristics of PEDOT:PSS Thin-Film Devices with Different Thicknesses on Polyimide Substrates

    NASA Astrophysics Data System (ADS)

    Anno, Hiroaki; Nishinaka, Takahiko; Hokazono, Masahiro; Oshima, Nobuaki; Toshima, Naoki

    2015-06-01

    We fabricated cast films of complexes of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid (PEDOT:PSS) at various thicknesses, t = 3-20 μm, on flexible polyimide substrates, and studied their thermoelectric properties. We also fabricated in-plane film devices consisting of five couples of PEDOT:PSS and Ag electrodes, measuring their output power characteristics as a function of film thickness. The Seebeck coefficient and electrical conductivity of a PEDOT:PSS film with a thickness of ˜20 μm on a polyimide substrate were ˜15 μV/K and 500 S/cm, respectively, near room temperature. As the film thickness decreased from ˜10 μm to 3 μm, the electrical conductivity increased remarkably to 1200 S/cm, while the Seebeck coefficient remained almost constant with film thickness. The maximum electric power for an in-plane PEDOT:PSS film device with a thickness of 10 μm was 1.3 μW at Δ T = 100 K. Its open-circuit voltage was 7.3 mV, and its internal resistance was 11 Ω. The measured power-generation characteristics of the film device agreed with values estimated from the dependence of thermoelectric properties on film thickness for PEDOT:PSS films on polyimide substrates. Assuming single PEDOT:PSS legs, defined as the direction of heat transport, we estimated the expected electrical power density at Δ T = 100 K as ˜650 μW/cm2 for a film thickness t = 10 μm, and 1400 μW/cm2 for t = 3 μm.

  11. Mg2(Si,Sn)-based thermoelectric materials and devices

    NASA Astrophysics Data System (ADS)

    Gao, Peng

    Thermoelectric effects are phenomena found in materials that can achieve direct conversion between heat flow and electricity. One important application of thermoelectric effects is thermoelectric generators, which can generate electricity when a temperature gradient is applied. Thermoelectric generators make use of various sources of heat and it is considered a promising solution for waste heat recovery. The conversion efficiency of thermoelectric generators depends on the materials used in the devices. Significant improvement in the performance of thermoelectric materials has been made in the past few decades. However, most of the good thermoelectric materials being investigated have limitations, such as the high materials cost, high materials density and toxicity of the constituent elements. The Mg2(Si,Sn)-based materials studied in this work are promising candidates for thermoelectric generators in the mid-temperature range and have drawn increasing research interest in recent years because these materials are high performance thermoelectrics that are low cost, low-density and non-toxic. In this work, systematic studies were performed on the Mg2(Si,Sn) thermoelectric materials. Thermal phase stability was studied for different compositions of Mg2Si1-xSnx and Mg2Si0.4Sn 0.6 was used as base material for further optimization. Both n-type and p-type samples were obtained by doping the materials with different elements. Peak ZT ˜ 1.5 for the n-type and ZT ˜ 0.7 for the p-type materials were obtained, both of which are among the best reported results so far. Experimental work was also done to study the techniques to develop the Mg2Si 0.4Sn0.6 materials into working devices. Different electrode materials were tested in bonding experiment for this compound, and copper was found to be the best electrode material for Mg2Si 0.4Sn0.6. Preliminary work was done to demonstrate the possibility of fabricating a Mg2Si0.4Sn0.6-based thermoelectric generator and the result is

  12. Multilayer thermoelectric films: A strategy for the enhancement of ZT

    SciTech Connect

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

    1995-03-01

    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.

  13. Shockwave Consolidation of Nanostructured Thermoelectric Materials

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  14. Thermoelectric Devices Advance Thermal Management

    NASA Technical Reports Server (NTRS)

    2007-01-01

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

  15. On the Challenges of Reducing Contact Resistances in Thermoelectric Generators Based on Half-Heusler Alloys

    NASA Astrophysics Data System (ADS)

    Ngan, Pham Hoang; Van Nong, Ngo; Hung, Le Thanh; Balke, Benjamin; Han, Li; Hedegaard, Ellen Marie Jensen; Linderoth, Søren; Pryds, Nini

    2016-01-01

    A method using fast hot pressing to join half-Heusler (HH) thermoelectric materials directly to an electrical current collector (Ag electrode) without using a third filler material is introduced. The compositions of the HH alloys used are Hf0.5Zr0.5CoSn0.2Sb0.8 and Ti0.6Hf0.4NiSn for p- and n-type, respectively. Using this method, the quality of the HH-electrode contacts is improved due to their low electrical contact resistance and less reaction-diffusion layer. The microstructure and chemical composition of the joints were examined using a scanning electron microscope equipped with energy-dispersive x-ray analysis. The electrical characteristics of the interfaces at the contacts were studied based on electrical contact resistance and Seebeck scanning microprobe measurements. In this paper, we show that joining the HH to a Ag electrode directly using fast hot pressing resulted in lower contact resistance and better performance compared with the method of using active brazing filler alloy.

  16. Methods of synthesizing thermoelectric materials

    DOEpatents

    Ren, Zhifeng; Chen, Shuo; Liu, Wei-Shu; Wang, Hengzhi; Wang, Hui; Yu, Bo; Chen, Gang

    2016-04-05

    Methods for synthesis of thermoelectric materials are disclosed. In some embodiments, a method of fabricating a thermoelectric material includes generating a plurality of nanoparticles from a starting material comprising one or more chalcogens and one or more transition metals; and consolidating the nanoparticles under elevated pressure and temperature, wherein the nanoparticles are heated and cooled at a controlled rate.

  17. Thermoelectric module

    DOEpatents

    Kortier, William E.; Mueller, John J.; Eggers, Philip E.

    1980-07-08

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  19. Thermoelectric-Driven Autonomous Sensors for a Biomass Power Plant

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  20. Numerical Examination of the Performance of a Thermoelectric Cooler with Peltier Heating and Cooling

    NASA Astrophysics Data System (ADS)

    Kim, Chang Nyung; Kim, Jeongho

    2015-10-01

    There has recently been much progress in the development of materials with higher thermoelectric performance, leading to the design of thermoelectric devices for generation of electricity and for heating or cooling. Local heating can be achieved by current flow through an electric resistance, and local heating and cooling can be performed by Peltier heating and cooling. In this study, we developed computer software that can be used to predict the Seebeck and Peltier effects for thermoelectric devices. The temperature, electric potential, heat flow, electric current, and coefficient of performance were determined, with the objective of investigating the Peltier effect in a thermoelectric device. In addition to Peltier heating and cooling, Joule and Thomson heating were quantitatively evaluated for the thermoelectric device.

  1. Modelling of segmented high-performance thermoelectric generators with effects of thermal radiation, electrical and thermal contact resistances

    NASA Astrophysics Data System (ADS)

    Ouyang, Zhongliang; Li, Dawen

    2016-04-01

    In this study, segmented thermoelectric generators (TEGs) have been simulated with various state-of-the-art TE materials spanning a wide temperature range, from 300 K up to 1000 K. The results reveal that by combining the current best p-type TE materials, BiSbTe, MgAgSb, K-doped PbTeS and SnSe with the strongest n-type TE materials, Cu-Doped BiTeSe, AgPbSbTe and SiGe to build segmented legs, TE modules could achieve efficiencies of up to 17.0% and 20.9% at ΔT = 500 K and ΔT = 700 K, respectively, and a high output power densities of over 2.1 Watt cm‑2 at the temperature difference of 700 K. Moreover, we demonstrate that successful segmentation requires a smooth change of compatibility factor s from one end of the TEG leg to the other, even if s values of two ends differ by more than a factor of 2. The influence of the thermal radiation, electrical and thermal contact effects have also been studied. Although considered potentially detrimental to the TEG performance, these effects, if well-regulated, do not prevent segmentation of the current best TE materials from being a prospective way to construct high performance TEGs with greatly enhanced efficiency and output power density.

  2. Maximum power output and load matching of a phosphoric acid fuel cell-thermoelectric generator hybrid system

    NASA Astrophysics Data System (ADS)

    Chen, Xiaohang; Wang, Yuan; Cai, Ling; Zhou, Yinghui

    2015-10-01

    Based on the current models of phosphoric acid fuel cells (PAFCs) and thermoelectric generators (TGs), a new hybrid system is proposed, in which the effects of multi-irreversibilities resulting from the activation, concentration, and ohmic overpotentials in the PAFC, Joule heat and heat leak in the TG, finite-rate heat transfer between the TG and the heat reservoirs, and heat leak from the PAFC to the environment are taken into account. Expressions for the power output and efficiency of the PAFC, TG, and hybrid system are analytically derived and directly used to discuss the performance characteristics of the hybrid system. The optimal relationship between the electric currents in the PAFC and TG is obtained. The maximum power output is numerically calculated. It is found that the maximum power output density of the hybrid system will increase about 150 Wm-2, compared with that of a single PAFC. The problem how to optimally match the load resistances of two subsystems is discussed. Some significant results for practical hybrid systems are obtained.

  3. Modelling of segmented high-performance thermoelectric generators with effects of thermal radiation, electrical and thermal contact resistances

    PubMed Central

    Ouyang, Zhongliang; Li, Dawen

    2016-01-01

    In this study, segmented thermoelectric generators (TEGs) have been simulated with various state-of-the-art TE materials spanning a wide temperature range, from 300 K up to 1000 K. The results reveal that by combining the current best p-type TE materials, BiSbTe, MgAgSb, K-doped PbTeS and SnSe with the strongest n-type TE materials, Cu-Doped BiTeSe, AgPbSbTe and SiGe to build segmented legs, TE modules could achieve efficiencies of up to 17.0% and 20.9% at ΔT = 500 K and ΔT = 700 K, respectively, and a high output power densities of over 2.1 Watt cm−2 at the temperature difference of 700 K. Moreover, we demonstrate that successful segmentation requires a smooth change of compatibility factor s from one end of the TEG leg to the other, even if s values of two ends differ by more than a factor of 2. The influence of the thermal radiation, electrical and thermal contact effects have also been studied. Although considered potentially detrimental to the TEG performance, these effects, if well-regulated, do not prevent segmentation of the current best TE materials from being a prospective way to construct high performance TEGs with greatly enhanced efficiency and output power density. PMID:27052592

  4. Efficient and Robust Thermoelectric Power Generation Device Using Hot-Pressed Metal Contacts on Nanostructured Half-Heusler Alloys

    NASA Astrophysics Data System (ADS)

    Joshi, Giri; Poudel, Bed

    2016-06-01

    We report an efficient thermoelectric device with power density of 8.9 W/cm2 and efficiency of 8.9% at 678°C temperature difference using hot-pressed titanium metal contact layers on nanostructured half-Heusler materials. The high power density and efficiency are due to the efficient nanostructured materials and very low contact resistance of ~1 μΩ cm2 between the titanium layer and half-Heusler material. Moreover, the bonding strength between the titanium and half-Heusler is more than 50 MPa, significantly higher compared with conventional contact metallization methods. The low contact resistance and high bonding strength are due to thin-layer diffusion of titanium (<100 μm) into the half-Heusler at high temperature (>600°C). The low contact resistance and high bonding strength result in a stable and efficient power generation device with great potential for use in recovery of waste heat, e.g., in automotive and industrial applications.

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

    NASA Technical Reports Server (NTRS)

    Reier, M.

    1972-01-01

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

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

    SciTech Connect

    Not Available

    1984-03-01

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

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

    NASA Astrophysics Data System (ADS)

    Crane, D. T.

    2011-05-01

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

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

    SciTech Connect

    Heenan, P.; Mathiprakasam, B.; DeMott, D.

    1994-08-10

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

  9. Coupled improvement between thermoelectric and piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Montgomery, David; Hewitt, Corey; Dun, Chaochao; Carroll, David

    A novel coupling effect in a thermoelectric and piezoelectric meta-structure is discussed. Thermo-piezoelectric generators (TPEGs) exhibit a synergistic effect that amplifies output voltage, and has been observed to increase piezoelectric voltages over 500% of initial values a time dependent thermoelectric/pyroelectric effect. The resulting improvement in voltage has been observed in carbon nanotubes as well as inorganics such as two-dimensional Bismuth Selenide platelets and Telluride nanorods thin-film thermoelectrics. TPEGs are built by integrating insulating layers of polyvinylidene fluoride (PVDF) piezoelectric films between flexible thin film p-type and n-type thermoelectrics. The physical phenomena arising in the interaction between thermoelectric and piezoelectrics is discussed and a model is presented to quantify the expected coupling voltage as a function of stress, thermal gradient, and different thermoelectric materials. TPEG are ideal to capture waste heat and vibrational energy while creating larger voltages and minimizing space when compared with similar thermoelectric or piezoelectric generators.

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

    PubMed

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

    2013-11-27

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

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

    PubMed

    Kraemer, D; Chen, G

    2014-04-01

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

  12. Power-Generation Characteristics After Vibration and Thermal Stresses of Thermoelectric Unicouples with CoSb3/Ti/Mo(Cu) Interfaces

    NASA Astrophysics Data System (ADS)

    Bae, Kwang Ho; Choi, Soon-Mok; Kim, Kyung-Hun; Choi, Hyoung-Seuk; Seo, Won-Seon; Kim, Il-Ho; Lee, Soonil; Hwang, Hae Jin

    2015-06-01

    Reliability tests for thermoelectric unicouples were carried out to investigate the adhesion properties of CoSb3/Ti/Mo(Cu) interfaces. The n-type In0.25 Co3.95Ni0.05Sb12 and p-type In0.25Co3FeSb12 bulks were prepared for fabricating a thermoelectric unicouple (one p- n couple) by an induction melting and a spark plasma sintering process. Mo-Cu alloy was selected as an electrode for the unicouples due to its high melting temperature and proper work function value. Many thermoelectric unicouples with the CoSb3/Ti/Mo(Cu) interfaces were fabricated with the proper brazing materials by means of a repeated firing process. Reliability of the unicouples with the interfaces was evaluated by a vibration test and a thermal cycling test. After the thermal cycling and vibration tests, the power-generation characteristics of the unicouples were compared with the unicouples before the tests. Even after the vibration test, electrical power with a power density of 0.5 W/cm2 was generated. The Ti-interlayer is considered as a possible candidate for making a reliable unicouple with high adhesion strength. With the thermal cycling test, the resistance of the unicouple increased and the electrical power from the unicouple decreased. A failure mode by the thermal cycling test was ascribed to a complex effect of micro-cracks originated from the thermal stress and oxidation problem of the thermoelectric materials; that is, a thick oxide layer more than 300 μm was detected after a high-temperature durability test of n-type In0.25Co3.95Ni0.05Sb12 material at 773 K in air for 7 days.

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

    SciTech Connect

    Hammond, J.P.

    1981-12-01

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

  14. Thermoelectric and spin-caloritronic coolers: from basics to recent developments

    NASA Astrophysics Data System (ADS)

    Heremans, Joseph P.; Jin, Hyungyu

    2016-03-01

    Solid-state coolers have no moving parts, and are therefore compact, vibration-free, inherently durable, and scalable to low power levels. Unfortunately, they have a low coefficient of performance. The materials characteristic that sets this efficiency in solid-state coolers is the thermoelectric figure of merit, zT. This article reviews the factors limiting zT in conventional thermoelectric devices, then outlines modern approaches to increasing zT. It describes a new solid-state energy conversion technology, the spin-Seebeck effect (SSE). New concepts are outlined that combine classical thermoelectric and SSE physics. By exploiting the spin degree of freedom, we hope to increase the performance of solid-state coolers.

  15. Thermodynamics of Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Doak, Jeff W.

    One challenge facing society is the responsible use of our energy resources. Increasing the efficiency of energy generation provides one path to solving this challenge. One commonality among most current energy generation methods is that waste heat is generated during the generation process. Thermoelectrics can provide a solution to increasing the efficiency of power generation and automotive systems by converting waste heat directly to electricity. The current barrier to implementation of thermoelectric systems is the low efficiencies of underlying thermoelectric materials. The efficiency of a thermoelectric material depends on the electronic and thermal transport properties of the material; a good thermoelectric material should be an electronic conductor and a thermal insulator, traits which generally oppose one another. The thermal properties of a thermoelectric material can be improved by forming nanoscale precipitates with the material which scatter phonons, reducing the thermal conductivity. The electronic properties of a thermoelectric material can be improved by doping the material to increase the electronic conductivity or by alloying the material to favorably alter its band structure. The ability of these chemical modifications to affect the thermoelectric efficiency of material are ultimately governed by the chemical thermodynamics of the system. PbTe is a prototypical thermoelectric material: Alloying PbTe with PbS (or other materials) creates nanostructures which scatter phonons and reduce the lattice thermal conductivity. Doping PbTe with Na increases the hole concentration, increasing the electronic conductivity. In this work, we investigate the thermodynamics of PbTe and similar systems using first principles to understand the underlying mechanisms controlling the formation of nanostructures and the amount of doping allowed in these systems. In this work we: 1) investigate the thermodynamics of pseudo-binary alloys of IV--VI systems to identify the

  16. Thermoelectric system

    DOEpatents

    Reiners, Eric A.; Taher, Mahmoud A.; Fei, Dong; McGilvray, Andrew N.

    2007-10-30

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

  17. Measuring Thermoelectric Properties Automatically

    NASA Technical Reports Server (NTRS)

    Chmielewski, A.; Wood, C.

    1986-01-01

    Microcomputer-controlled system speeds up measurements of Hall voltage, Seebeck coefficient, and thermal diffusivity in semiconductor compounds for thermoelectric-generator applications. With microcomputer system, large data base of these parameters gathered over wide temperature range. Microcomputer increases measurement accuracy, improves operator productivity, and reduces test time.

  18. 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...

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

    PubMed

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

    2013-08-01

    We present an in-depth analysis of the sometimes understated role of the principle of energy conservation in linear irreversible thermodynamics. Our case study is that of a thermoelectric generator (TEG), which is a heat engine of choice in irreversible thermodynamics, owing to the coupling between the electrical and heat fluxes. We show why Onsager's reciprocal relations must be considered locally and how internal dissipative processes emerge from the extension of these relations to a global scale: The linear behavior of a heat engine at the local scale is associated with a dissipation process that must partake in the global energy balance. We discuss the consequences of internal dissipations on the so-called efficiency at maximum power, in the light of our comparative analyses of exoreversibility and endoreversibility on the one hand and of two classes of heat engines, autonomous and periodically driven, on the other hand. Finally, basing our analysis on energy conservation, we also discuss recent works which claim the possibility to overcome the traditional boundaries on efficiency imposed by finite-time thermodynamics in thermoelectric systems with broken time-reversal symmetry; this we do by introducing a "thermal" thermopower and an "electrical" thermopower which permits an analysis of the thermoelectric response of the TEG considering a possible dissymmetry between the electrical/thermal and the thermal/electrical couplings. PMID:24032805

  20. Monolayer MoS2 Nanoribbons as a Promising Material for Both n-type and p-type Legs in Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    Arab, A.; Davydov, A. V.; Papaconstantopoulos, D. A.; Li, Q.

    2016-06-01

    First-principles calculations have been performed to study the thermoelectric properties of monolayer MoS2 armchair nanoribbons (ACNRs). The electronic behavior of nanoribbons is dominated by the presence of edge states that are dependent on the number of zigzag chains across the nanoribbon. In addition, it is found that the phonon thermal conductance of monolayer MoS2 ACNRs is smaller than monolayer films due to phonon edge scattering. This effect is more pronounced in narrower nanoribbons, which leads to a higher ZT value compared to a monolayer MoS2 sheet. The effects of sulfur vacancy and edge roughness on the thermoelectric properties of MoS2 ACNRs have also been studied. We found that edge roughness decreased ZT values compared to those of perfect nanoribbons, as its impact on electrical conductance is more severe than on phonon thermal conductance. Sulfur vacancy, however, improved ZT in some subbands. It is shown that ZT values as high as 4 for electron-doped and 3 for hole-doped nanoribbons can be achieved at T = 500 K. The ability to achieve high ZT values for both p-type and n-type nanoribbons makes monolayer MoS2 ACNR a promising candidate for future solid-state thermoelectric generators.

  1. Semimetal/semiconductor nanocomposites for thermoelectrics.

    PubMed

    Lu, Hong; Burke, Peter G; Gossard, Arthur C; Zeng, Gehong; Ramu, Ashok T; Bahk, Je-Hyeong; Bowers, John E

    2011-05-24

    In this work, we present research on semimetal-semiconductor nanocomposites grown by molecular beam epitaxy (MBE) for thermoelectric applications. We study several different III-V semiconductors embedded with semimetallic rare earth-group V (RE-V) compounds, but focus is given here to ErSb:In(x)Ga(1−x)Sb as a promising p-type thermoelectric material. Nanostructures of RE-V compounds are formed and embedded within the III-V semiconductor matrix. By co-doping the nanocomposites with the appropriate dopants, both n-type and p-type materials have been made for thermoelectric applications. The thermoelectric properties have been engineered for enhanced thermoelectric device performance. Segmented thermoelectric power generator modules using 50 μ m thick Er-containing nanocomposites have been fabricated and measured. Research on different rare earth elements for thermoelectrics is discussed. PMID:21751469

  2. Semimetal/Semiconductor Nanocomposites for Thermoelectrics

    SciTech Connect

    Lu, Hong; Burke, Peter G.; Gossard, Arthur C.; Zeng, Gehong; Ramu, Ashok T.; Bahk, Je-Hyeong; Bowers, John E.

    2011-04-15

    In this work, we present research on semimetal-semiconductor nanocomposites grown by molecular beam epitaxy (MBE) for thermoelectric applications. We study several different III-V semiconductors embedded with semimetallic rare earth-group V (RE-V) compounds, but focus is given here to ErSb:InxGa1-xSb as a promising p-type thermoelectric material. Nano­structures of RE-V compounds are formed and embedded within the III-V semiconductor matrix. By codoping the nanocomposites with the appropriate dopants, both n-type and p-type materials have been made for thermoelectric applications. The thermoelectric properties have been engineered for enhanced thermoelectric device performance. Segmented thermoelectric power generator modules using 50 μm thick Er-containing nanocomposites have been fabricated and measured. Research on different rare earth elements for thermoelectrics is discussed.

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

    SciTech Connect

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

    1995-10-01

    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.).

  4. Radioisotope Thermoelectric Generator Transportation System licensed hardware second certification test series and package shock mount system test

    NASA Astrophysics Data System (ADS)

    Ferrell, Patrick C.; Moody, Donald A.

    1996-03-01

    This paper presents a summary of two separate drop test activities that were 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 U.S. 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.).

  5. Radioisotope Thermoelectric Generator Transportation System licensed hardware second certification test series and package shock mount system test

    SciTech Connect

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

    1996-03-01

    This paper presents a summary of two separate drop test activities that were 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 {ital Title} 10, {ital Code} {ital of} {ital Federal} {ital Regulations}, {open_quote}{open_quote}Part 71{close_quote}{close_quote} (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 U.S. Department of Energy{close_quote}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, {ital Transit} {ital Drop} {ital Procedure} (DOE 1989), was used to verify that the shock limiting system limited accelerations in excess of 15 G{close_quote}s at frequencies below 150 Hz. Results of the package mount drop tests indicate that an impact force of 15 G{close_quote}s was not exceeded in any test from a free drop height of 457 mm (18 in.). {copyright} {ital 1996 American Institute of Physics.}

  6. Thermoelectric Products

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Instead of bulky coils and compressors used in conventional refrigeration systems, UST design engineers drew on thermo-electric technology. UST's precision temperature chambers (PTC's) feature small thermoelectric modules that measure not much more than 1 square inch and operate on unique phenomenon of heat exchange. When electric current flows through specialized metallic crystals, heat is produced; when current direction is reversed cooling is produced.

  7. Revisiting an idea of G D Botto: a solar thermoelectric generator

    NASA Astrophysics Data System (ADS)

    DeLuca, R.; Ganci, S.; Zozzaro, P.

    2008-11-01

    In an experiment performed by G D Botto in 1833 it was shown that it was possible to produce hydrogen gas by hydrolysis by means of an electromotive force obtained by connecting in series more than 100 thermocouples heated by a flame of burning alcohol. In the system we study, we adopt the same basic idea for an electro-thermal converter, by assuming that concentrated solar radiation heats N thermocouples in series to generate an electromotive force f0.

  8. Vibration Testing of the Pluto/New Horizons Radioisotope Thermoelectric Generator

    SciTech Connect

    Charles D. Griffin

    2006-06-01

    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.

  9. Bottom-up silicon nanowire-based thermoelectric microgenerators

    NASA Astrophysics Data System (ADS)

    Dávila, D.; Huber, R.; Hierold, C.

    2015-12-01

    In this work, bottom-up intrinsic crystalline Si nanowire arrays in combination with top-down microfabrication techniques and a vertical device architecture have been proposed to develop an all-silicon nanostructured thermoelectric generator. To fabricate this device, a suitable vertical integration of Si NWs on patterned microstructures, which define the thermoelectric legs of the generator, has been achieved by bonding top and bottom silicon structures through nanowires. The process has been proven to be a feasible approach that employs a regrowth process of the nanowires for bonding purposes.

  10. Thermal Expansion Studies of Selected High-Temperature Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

  11. Thermal Expansion Studies of Selected High Temperature Thermoelectric Materials

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  12. Inverse Problems of Thermoelectricity

    NASA Astrophysics Data System (ADS)

    Anatychuk, L. I.; Luste, O. J.; Kuz, R. V.; Strutinsky, M. N.

    2011-05-01

    Classical thermoelectricity is based on the use of the Seebeck and Thomson effects that occur in the near-contact areas between n- and p-type materials. A conceptually different approach to thermoelectric power converter design that is based on the law of thermoelectric induction of currents is also known. The efficiency of this approach has already been demonstrated by its first applications. More than 10 basically new types of thermoelements were discovered with properties that cannot be achieved by thermocouple power converters. Therefore, further development of this concept is of practical interest. This paper provides a classification and theory for solving the inverse problems of thermoelectricity that form the basis for devising new thermoelement types. Computer methods for their solution for anisotropic and inhomogeneous media are elaborated. Regularities related to thermoelectric current excitation in anisotropic and inhomogeneous media are established. The possibility of obtaining eddy currents of a particular configuration through control of the temperature field and material parameters for the creation of new thermo- element types is demonstrated for three-dimensional (3D) models of anisotropic and inhomogeneous media.

  13. Advanced Radioisotope Power Systems Segmented Thermoelectric Research

    NASA Technical Reports Server (NTRS)

    Caillat, Thierry

    2004-01-01

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

  14. Smart pavement sensor based on thermoelectricity power

    NASA Astrophysics Data System (ADS)

    Yu, Xiong; Zhang, Bin; Tao, Junliang; Liu, Zhen

    2010-04-01

    The aging infrastructure requires a proactive strategy to ensure their functionality and performance. Innovative sensors are needed to develop infrastructures that are intelligent and adaptive. A power supply strategy is among the crucial components to reduce the instrument cost and to ensure the long term function of these embedded sensors. This paper introduces the results of a preliminary study on using thermo-electricity generation to power sensors. This presents an innovative strategy for long term monitoring of pavement performance.

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

    SciTech Connect

    Lockwood, A.; Shields, V.

    1980-11-01

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

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

    SciTech Connect

    Lockwood, A.; Shields, V.

    1980-05-01

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

  17. Test System for Thermoelectric Modules and Materials

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  18. Power-Generation Performance of a π-Structured Thermoelectric Module Containing Mg2Si and MnSi1.73

    NASA Astrophysics Data System (ADS)

    Nakamura, Tomoyuki; Hatakeyama, Kazuya; Minowa, Masahiro; Mito, Youhiko; Arai, Koya; Iida, Tsutomu; Nishio, Keishi

    2015-10-01

    In recent years, environmental problems, for example global warming and depletion of energy resources, have become serious. Thermoelectric power generation has attracted attention as a means of reducing the effects of such problems. Thermoelectric conversion technology can convert thermal energy directly into electrical energy. Therefore, exhaust heat can be converted into electrical energy. Moreover, it is a clean method of power generation that does not discharge CO2 gas when the electricity is generated. The purpose of this study was to fabricate a thermoelectric (TE) module that can be used at mid-range temperatures of 573-873 K. The component materials selected were Mg2Si as n-type semiconductor and MnSi1.73 as p-type semiconductor. These compounds are non-toxic, environmentally benign, lightweight, and relatively abundant compared with other TE compounds. Ag paste was used to join the components. To prevent diffusion of Ag at the interface of the components and the electrodes, the top and bottom of the components were coated with Ni. The TE module was composed of 12 pairs of elements and Ag seats were used for the electrodes. The dimensions of both p and n-type components were 5.0 mm × 5.0 mm × 6.3 mm. Module size was 36.5 mm × 36.0 mm × 7.0 mm, and alumina was used as substrate. The module was inserted between hot and cold plates, in air, and output power was measured. The open circuit voltage and the maximum output power were 1.6 V and 5.6 W, respectively, at Δ T = 548°C (hot side 587°C; cold side 39°C), and the output power density estimated from these results was 4.4 kW/m2.

  19. Thermoelectric efficiency and compatibility.

    PubMed

    Snyder, G Jeffrey; Ursell, Tristan S

    2003-10-01

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

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

    SciTech Connect

    Lockwood, A.; Shields, V.

    1980-09-01

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

  1. Thermal and Thermoelectric Transport in Thin Films and Nanostructures

    NASA Astrophysics Data System (ADS)

    Zink, B. L.; Sultan, R.; Avery, A. D.

    2009-03-01

    Interest in increasing efficiency of energy generation continues to spur the development of new thermoelectric materials. Though bulk materials hold the most promise for large-scale energy generation, many groups continue to explore increasing the thermoelectric figure-of-merit by taking advantage of techniques for creating nanostructured materials such as multilayered thin films and nanowires. These systems could prove to have high figures-of-merit and be important for integrating energy harvesting and/or cooling with micro- or nanoscale devices ``on chip.'' Though many promising systems have been identified, measuring their fundamental thermal transport often remains a major challenge. In this talk, we briefly describe our recent advances in measuring in-plane thermal transport, thermopower and electrical conductivity on thin-films or nanolithographically patterned systems. Our technique allows great flexibility for studying the thermoelectric properties of a wide range of materials, from amorphous semiconductors to semi-metallic nanowires.

  2. Nano-materials enabled thermoelectricity from window glasses.

    PubMed

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

    2012-01-01

    With a projection of nearly doubling up the world population by 2050, we need wide variety of renewable and clean energy sources to meet the increased energy demand. Solar energy is considered as the leading promising alternate energy source with the pertinent challenge of off sunshine period and uneven worldwide distribution of usable sun light. Although thermoelectricity is considered as a reasonable renewable energy from wasted heat, its mass scale usage is yet to be developed. Here we show, large scale integration of nano-manufactured pellets of thermoelectric nano-materials, embedded into window glasses to generate thermoelectricity using the temperature difference between hot outside and cool inside. For the first time, this work offers an opportunity to potentially generate 304 watts of usable power from 9 m(2) window at a 20°C temperature gradient. If a natural temperature gradient exists, this can serve as a sustainable energy source for green building technology. PMID:23150789

  3. Nano-materials Enabled Thermoelectricity from Window Glasses

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

  4. Band engineering of thermoelectric materials.

    PubMed

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

    2012-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

  6. Development and Investigation of the Method for Compensating Thermoelectric Inhomogeneity Error

    NASA Astrophysics Data System (ADS)

    Jun, Su; Kochan, Orest; Kochan, Volodymyr; Wang, Chunzhi

    2016-01-01

    The method proposed in this paper is one of the best methods for neutralizing the impact of error due to acquired thermoelectric inhomogeneity of thermocouples' electrodes. This method's main idea is stabilization of temperature along the thermoelectrodes of the thermocouple that measures temperature of an object. The description of a furnace design that provides a stable temperature field, as well as the methods for controlling the temperature field profile, together with their experimental evidence, is also provided.

  7. Synthetic Development of Metal Silicide Nanowires for Thermoelectric and Spintronic Applications

    NASA Astrophysics Data System (ADS)

    Higgins, Jeremy Michael

    2011-12-01

    Nanomaterials, including nanowires (NWs), are a new class of materials with the potential to lead to major changes in many aspects of human society. Innumerable applications for nanomaterials are envisioned or are being realized now. However, such new functionalities are and will continue to be predicated on our ability to precisely synthesize nanomaterials, a skill yet undeveloped in a majority of chemical systems. Metal silicides are a class of refractory intermetallic compounds composed of abundant elements with widely varying properties that are currently employed in a large range of technological applications. In this thesis, I describe my exploration of metal silicide NWs, particularly those in the Mn-Si binary system, in order to develop rational synthetic strategies for accessing binary and ternary silicide NWs and characterize their potential for thermoelectric and spintronic applications. Chapter 1 develops a common set of ideas and a common language before reviewing the current "state of the art" in silicide NW synthesis, exploring a number of the mysteries still surrounding silicide NW synthesis, and presenting silicide NW applications. Chapter 2 depicts the use of Mn(CO) 5SiCl3 as the vapor phase precursor to synthesize higher manganese silicide NWs (also known as HMS, MnSi˜1.7 MnSi2--x) for the first time, the identification of the NW subphase as Mn19Si33, and conductivity measurement on HMS NWs revealing bulk-like behavior. Chapter 3 describes employing MnCl 2 as the precursor for the first successful synthesis of MnSi NWs and transverse magnetoresistance measurements on these MnSi NWs to observe the signatures of helimagnetism in NWs for the first time. Chapter 4 is a systematic examination of silicide NW synthesis by single source precursor chemical vapor deposition, highlighting the complex interplay of substrate diffusion and vapor phase reactivity giving rise to material incorporation in silicide NWs. Chapter 5 details the direct reaction of Mn

  8. Development of ethenetetrathiolate hybrid thermoelectric materials consisting of cellulose acetate and semiconductor nanomaterials

    NASA Astrophysics Data System (ADS)

    Asano, Hitoshi; Sakura, Naoko; Oshima, Keisuke; Shiraishi, Yukihide; Toshima, Naoki

    2016-02-01

    We investigated novel organic/inorganic hybrid thermoelectric materials prepared using several metal-polymer complexes, binders (insulating polymers), and inorganic semiconductor nanomaterials. It was found that the three-component hybrid thermoelectric materials, which consisted of nanodispersed poly(nickel 1,1,2,2-ethenetetrathiolate) (Ni-PETT), cellulose acetate (CA), and carbon nanotubes (CNTs), showed high thermoelectric performance. Ni-PETT had a large negative Seebeck coefficient of -42 µV K-1 and was an n-type semiconducting polymer complex. Ni-PETT sufficiently dispersed p-type CNTs in N-methyl-2-pyrrolidone. The charge transfer interaction between Ni-PETT and CNTs could provide a strong contact. Good films could be obtained by using CA as a binder. In addition, the electrical conductivity of the three-component hybrid films was increased by methanol treatment. The Seebeck coefficient, electrical conductivity, and power factor of Ni-PETT/CA/CNT films normalized on the basis of the CNT mass were 1.9, 5.2, and 2.8 times higher than those of the CNT sheets.

  9. Thermoelectric characterization and fabrication of nanostructured p-type Bi0.5Sb1.5Te3 and n-type Bi2Te3 thin film thermoelectric energy generator with an in-plane planar structure

    NASA Astrophysics Data System (ADS)

    Park, No-Won; Park, Tae-Hyun; Ahn, Jay-Young; Kang, So-Hyeon; Lee, Won-Yong; Yoon, Young-Gui; Yoon, Soon-Gil; Lee, Sang-Kwon

    2016-06-01

    This paper presents in-plane bismuth-telluride-based thermoelectric (TE) energy generators fabricated using metal-shadow and radio-frequency sputtering methods at room temperature. The TE energy generators consist of four couples of 300-nm-thick nanostructured Bi2Te3 (n-BT) and Bi0.5Sb1.5Te3 (p-BST) thin films used as n-type and p-type materials, respectively, on a Si substrate for the p/n junctions of the TE energy generators. Furthermore, the effect of annealing treatment of both n-BT and p-BST thin films on the electrical and TE properties as well as the TE performance of the TE energy generators is discussed. By varying the temperature between the hot and cold junction legs of the n-BT/p-BST in-plane TE energy generators annealed at 200 °C, the maximum output voltage and power are determined to be ˜3.6 mV and ˜1.1 nW, respectively, at a temperature difference of 50 K. The output powers increased by ˜590% compared to that of the as-grown TE generator at a temperature difference of 90 K. This improvement in the TE performance is attributed to the enhancement of the electrical conductivity after heat treatment. From a numerical simulation conducted using a commercial software (COMSOL), we are confident that it plays a crucial role in determining the dimension (i.e., thickness of each leg) and material properties of both n-BT and p-BST materials of the in-plane TE energy generators.

  10. Thermoelectric Generators from AgBiTe and AgSbTe Thin Films Modified by High-Energy Beam

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    The ternary chalcogenides AgBiTe2 and AgSbTe2 belong to the family of semiconductors with disordered NaCl cubic structure in which Ag and Sb occupy metal sublattices. Both compounds are very interesting due to their thermoelectric properties. We have grown single-layer AgBiTe and AgSbTe thin films on silicon (Si) and fused silica (Suprasil) substrates using electron beam deposition. High-energy (MeV) Si-ion bombardment was performed on the thin-film samples at five different fluences between 5 × 1013 ions/cm2 and 7 × 1015 ions/cm2. We have measured the thermoelectric efficiency (figure of merit, ZT) of the fabricated thermoelectric devices by measuring the cross-plane thermal conductivity using the third-harmonic (3 ω) method, the cross-plane Seebeck coefficient, and the in-plane electrical conductivity using the van der Pauw method before and after MeV Si-ion bombardment. Rutherford backscattering spectrometry and the Rutherford Universal Manipulation Program (RUMP) simulation package were used to analyze the elemental composition and thickness of the deposited materials on the substrates. The RUMP simulation gave thicknesses for the AgBiTe and AgSbTe thin films of 270 nm and 188 nm, respectively. The figure of merit for AgBiTe started to decrease from the value of 0.37 for the virgin sample after bombardment. We saw similar decreasing behavior for the AgSbTe thin-film system. The figure of merit for AgSbTe started to decrease from the value of 0.88 for the virgin sample after bombardment. MeV Si-ion bombardment caused changes in the thermoelectric properties of the thin films.

  11. Water, Power, and Stress: Impacts of Thermoelectric Power Generation on Water Basins in the Coterminous U.S

    NASA Astrophysics Data System (ADS)

    Madden, N. T.; Averyt, K.; Huber-lee, A. T.; Levental, S.; Lewis, A.

    2011-12-01

    Thermoelectric power cooling represents the highest anthropogenic demand for water in the coterminous United States, accounting for over 41% of all freshwater taken from the environment. In watersheds where multiple power plants require water for cooling, these demands can significantly stress local water resources. Our study uses the Water Supply Stress Index, or WaSSI, to calculate the ratio of water demand to water supply for 2,106 8-digit hydrologic units nationwide (Sun et al. 2008). Water demand is determined by withdrawals from seven major user categories (commercial, domestic, industrial, irrigation, livestock, mining, thermoelectric), while supply is the sum of a) surface water supply; b) groundwater supply, based on historic rates of groundwater withdrawal; and c) return flows from major water users, including cities, agriculture and power plants. Water imported from other basins is not taken into account. To identify the basins where thermoelectric water use adds significantly to the water burden, we calculate the WaSSI for each basin nationwide, both with and without power-plant water use included. We find that power plants substantially exacerbate water stress in 44 basins, primarily located in California, the Great Lakes, the South Atlantic-Gulf, and the Colorado River. Our current work explores various indicators of stress in these "hotspots", in terms of water availability, increased water temperatures, and potential impacts to aquatic species.

  12. THERMO-ELECTRIC GENERATOR

    DOEpatents

    Jordan, K.C.

    1958-07-22

    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.

  13. Promising thermoelectric properties of phosphorenes.

    PubMed

    Sevik, Cem; Sevinçli, Hâldun

    2016-09-01

    Electronic, phononic, and thermoelectric transport properties of single layer black- and blue-phosphorene structures are investigated with first-principles based ballistic electron and phonon transport calculations employing hybrid functionals. The maximum values of room temperature thermoelectric figure of merit, ZT corresponding to armchair and zigzag directions of black-phosphorene, ∼0.5 and ∼0.25, are calculated as rather smaller than those obtained with first-principles based semiclassical Boltzmann transport theory calculations. On the other hand, the maximum value of room temperature ZT of blue-phosphorene is predicted to be substantially high and remarkable values as high as 2.5 are obtained for elevated temperatures. Besides the fact that these figures are obtained at the ballistic limit, our findings mark the strong possibility of high thermoelectric performance of blue-phosphorene in new generation thermoelectric applications. PMID:27455173

  14. Promising thermoelectric properties of phosphorenes

    NASA Astrophysics Data System (ADS)

    Sevik, Cem; Sevinçli, Hâldun

    2016-09-01

    Electronic, phononic, and thermoelectric transport properties of single layer black- and blue-phosphorene structures are investigated with first-principles based ballistic electron and phonon transport calculations employing hybrid functionals. The maximum values of room temperature thermoelectric figure of merit, ZT corresponding to armchair and zigzag directions of black-phosphorene, ∼0.5 and ∼0.25, are calculated as rather smaller than those obtained with first-principles based semiclassical Boltzmann transport theory calculations. On the other hand, the maximum value of room temperature ZT of blue-phosphorene is predicted to be substantially high and remarkable values as high as 2.5 are obtained for elevated temperatures. Besides the fact that these figures are obtained at the ballistic limit, our findings mark the strong possibility of high thermoelectric performance of blue-phosphorene in new generation thermoelectric applications.

  15. 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

    Zeng Gehong; Bahk, Je-Hyeong; Bowers, John E.; Lu Hong; Gossard, Arthur C.; Singer, Suzanne L.; Majumdar, Arun; Bian, Zhixi; Zebarjadi, Mona; Shakouri, Ali

    2009-08-24

    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.

  16. A Monolithic Oxide-Based Transversal Thermoelectric Energy Harvester

    NASA Astrophysics Data System (ADS)

    Teichert, S.; Bochmann, A.; Reimann, T.; Schulz, T.; Dreßler, C.; Udich, S.; Töpfer, J.

    2016-03-01

    We report the fabrication and properties of a monolithic transversal thermoelectric energy harvester based on the combination of a thermoelectric oxide and a metal. The fabrication of the device is done with a ceramic multilayer technology using printing and co-firing processes. Five transversal devices were combined to a meander-like thermoelectric generator. Electrical measurements and finite element calculations were performed to characterize the resulting thermoelectric generator. A maximum experimental electrical power output of 30.2 mW at a temperature difference of {Δ }T = 208 K was found. The prepared monolithic thermoelectric generator provides at {Δ }T = 35 K sufficient energy to drive a simple electronic sensor application.

  17. Thermoelectric refrigerator

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  18. New materials and devices for thermoelectric applications

    SciTech Connect

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

    1997-12-31

    The development of new, more efficient materials and devices is the key to expanding the range of application of thermoelectric generators and coolers. In the last couple of years, efforts to discover breakthrough thermoelectric materials have intensified, in particular in the US. Recent results on novel materials have already demonstrated that dimensionless figure of merit ZT values 40 to 50% larger than 1.0, the current limit, could be obtained in the 475 to 950 K temperature range. New terrestrial power generation 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 325--350 K, up to 850 to 1,100 K, 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--750 K temperature range to supplement or replace the alternator and thus decrease fuel consumption. Based on results achieved to date at the Jet Propulsion Laboratory (JPL) on novel materials, the performance of an advanced segmented generator design operating in a large 300--945 K temperature gradient is predicted to achieve about 15% conversion efficiency. This would be a very substantial improvement over state-of-the-art (SOA) thermoelectric power converters. Such a terrestrial power generator could be using waste heat or liquid fuels as a heat source. High performance radioisotope generators (RTG) are still of interest for deep space missions but the shift towards small, light spacecraft has developed a need for advanced power sources in the watt to milliwatt range. The powerstick concept would provide a study, compact, lightweight and low cost answer to this need. The development of thin film thermoelectric devices also offer attractive possibilities. The combination of semiconductor technology, thermoelectric films and high thermal

  19. Thermionic Energy Conversion (TEC) topping thermoelectrics

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1981-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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