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Sample records for solar thermoelectric generator

  1. 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.

  2. 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.

  3. Solar thermoelectric generators: Pushing the efficiency up

    NASA Astrophysics Data System (ADS)

    Toberer, Eric

    2016-11-01

    Concentrated thermoelectric generators convert solar energy to electricity, but historically their conversion efficiency has lagged behind their potential. Now, full system efficiencies of 7.4% are achieved by segmentation of two thermoelectric materials and a spectrally selective surface.

  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. Critical Concentration Ratio for Solar Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

    ur Rehman, Naveed; Siddiqui, Mubashir Ali

    2016-10-01

    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.

  6. 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.

  7. High-Temperature High-Efficiency Solar Thermoelectric Generators

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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 1000°C to 100°C. Achieving 15% overall STEG efficiency thus requires an absorber efficiency above 85%, and we consider two methods to achieve this: solar-selective absorbers and thermally insulating cavities. When the TEG and absorber subsystem models are combined, we expect that the STEG modeled here could achieve 15% efficiency with optical concentration between 250 and 300 suns.

  8. 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.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

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

  11. Performance Model and Sensitivity Analysis for a Solar Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Rehman, Naveed Ur; Siddiqui, Mubashir Ali

    2017-01-01

    In this paper, a regression model for evaluating the performance of solar concentrated thermoelectric generators (SCTEGs) is established and the significance of contributing parameters is discussed in detail. The model is based on several natural, design and operational parameters of the system, including the thermoelectric generator (TEG) module and its intrinsic material properties, the connected electrical load, concentrator attributes, heat transfer coefficients, solar flux, and ambient temperature. The model is developed by fitting a response curve, using the least-squares method, to the results. The sample points for the model were obtained by simulating a thermodynamic model, also developed in this paper, over a range of values of input variables. These samples were generated employing the Latin hypercube sampling (LHS) technique using a realistic distribution of parameters. The coefficient of determination was found to be 99.2%. The proposed model is validated by comparing the predicted results with those in the published literature. In addition, based on the elasticity for parameters in the model, sensitivity analysis was performed and the effects of parameters on the performance of SCTEGs are discussed in detail. This research will contribute to the design and performance evaluation of any SCTEG system for a variety of applications.

  12. Performance Model and Sensitivity Analysis for a Solar Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Rehman, Naveed Ur; Siddiqui, Mubashir Ali

    2017-03-01

    In this paper, a regression model for evaluating the performance of solar concentrated thermoelectric generators (SCTEGs) is established and the significance of contributing parameters is discussed in detail. The model is based on several natural, design and operational parameters of the system, including the thermoelectric generator (TEG) module and its intrinsic material properties, the connected electrical load, concentrator attributes, heat transfer coefficients, solar flux, and ambient temperature. The model is developed by fitting a response curve, using the least-squares method, to the results. The sample points for the model were obtained by simulating a thermodynamic model, also developed in this paper, over a range of values of input variables. These samples were generated employing the Latin hypercube sampling (LHS) technique using a realistic distribution of parameters. The coefficient of determination was found to be 99.2%. The proposed model is validated by comparing the predicted results with those in the published literature. In addition, based on the elasticity for parameters in the model, sensitivity analysis was performed and the effects of parameters on the performance of SCTEGs are discussed in detail. This research will contribute to the design and performance evaluation of any SCTEG system for a variety of applications.

  13. 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.

  14. 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)

  15. 300 WATT PORTABLE THERMOELECTRIC GENERATOR.

    DTIC Science & Technology

    THERMOELECTRICITY, POWER SUPPLIES), (* GENERATORS , THERMOELECTRICITY), (*ELECTRIC POWER PRODUCTION, THERMOELECTRICITY), PORTABLE EQUIPMENT, THERMOCOUPLES, ENERGY CONVERSION, HEAT EXCHANGERS, WIRING DIAGRAMS

  16. Preliminary characterization of ST2G: Solar thermionic-thermoelectric generator for concentrating systems

    NASA Astrophysics Data System (ADS)

    Bellucci, Alessandro; Calvani, Paolo; Cappelli, Emilia; Orlando, Stefano; Sciti, Diletta; Yogev, Ronen; Kribus, Abraham; Trucchi, Daniele M.

    2015-06-01

    An innovative conversion module (CM) for concentrating solar power applications, named ST2G (Solar Thermionic-Thermoelectric Generator), has been developed and fabricated. The new technology is based on a solid-state converter that works at temperatures up to 1000 °C and exploits a double conversion stage: a thermionic stage and a thermoelectric one, connected thermally in series. Potentially, the CM could reach a combined solar energy-to-electrical efficiency larger than 30%, producing also additional thermal energy to be exploited as a co-generation. Different prototypes have been fabricated and the discussion on the technological key-points has been reported, relating them to the physical requirements necessary for an efficient conversion mechanism. The preliminary results obtained at a lab-level are here discussed, indicating low electrical power output, but also how to increase the performance by solving the identified issues.

  17. 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

    2011-05-01

    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.

  18. Concentrating solar thermoelectric generators with a peak efficiency of 7.4%

    NASA Astrophysics Data System (ADS)

    Kraemer, Daniel; Jie, Qing; McEnaney, Kenneth; Cao, Feng; Liu, Weishu; Weinstein, Lee A.; Loomis, James; Ren, Zhifeng; Chen, Gang

    2016-11-01

    Concentrating solar power normally employs mechanical heat engines and is thus only used in large-scale power plants; however, it is compatible with inexpensive thermal storage, enabling electricity dispatchability. Concentrating solar thermoelectric generators (STEGs) have the advantage of replacing the mechanical power block with a solid-state heat engine based on the Seebeck effect, simplifying the system. The highest reported efficiency of STEGs so far is 5.2%. Here, we report experimental measurements of STEGs with a peak efficiency of 9.6% at an optically concentrated normal solar irradiance of 211 kW m-2, and a system efficiency of 7.4% after considering optical concentration losses. The performance improvement is achieved by the use of segmented thermoelectric legs, a high-temperature spectrally selective solar absorber enabling stable vacuum operation with absorber temperatures up to 600 ∘C, and combining optical and thermal concentration. Our work suggests that concentrating STEGs have the potential to become a promising alternative solar energy technology.

  19. 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.

  20. 100 WATT THERMOELECTRIC GENERATOR.

    DTIC Science & Technology

    GENERATORS , *ENERGY CONVERSION, HEAT EXCHANGERS, THERMOELECTRICITY, THERMOCOUPLES, BLOWERS, MODULES(ELECTRONICS), SILICON ALLOYS, GERMANIUM ALLOYS, COMBUSTION, GASOLINE, VAPORIZATION, FUELS, LEAD COMPOUNDS.

  1. 100 WATT THERMOELECTRIC GENERATOR.

    DTIC Science & Technology

    GENERATORS , THERMOELECTRICITY, THERMOCOUPLES, HEATERS, HEAT TRANSFER, ENERGY CONVERSION, GASOLINE, VOLTAGE REGULATORS, HEAT EXCHANGERS, LIFE EXPECTANCY(SERVICE LIFE), STARTING, PERFORMANCE(ENGINEERING).

  2. Experimental Analysis of Thermoelectric Heat Exchanger for Power Generation from Salinity Gradient Solar Pond Using Low-Grade Heat

    NASA Astrophysics Data System (ADS)

    Singh, Baljit; Baharin, Nuraida `Aadilia; Remeli, Muhammad Fairuz; Oberoi, Amandeep; Date, Abhijit; Akbarzadeh, Aliakbar

    2016-10-01

    Salinity gradient solar ponds act as an integrated thermal solar energy collector and storage system. The temperature difference between the upper convective zone and the lower convective zone of a salinity gradient solar pond can be in the range of 40-60°C. The temperature at the bottom of the pond can reach up to 90°C. Low-grade heat (<100°C) from solar ponds is currently converted into electricity by organic Rankine cycle engines. Thermoelectric generators can operate at very low temperature differences and can be a good candidate to replace organic Rankine cycle engines for power generation from salinity gradient solar ponds. The temperature difference in a solar pond can be used to power thermoelectric generators for electricity production. This paper presents an experimental investigation of a thermoelectric generators heat exchanger system designed to be powered by the hot water from the lower convective zone of a solar pond, and cold water from the upper convective zone of a solar pond. The results obtained have indicated significant prospects of such a system to generate power from low-grade heat for remote area power supply systems.

  3. 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.

  4. 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

    2016-06-10

    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.

  5. 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

  6. Experimental and theoretical analysis of a hybrid solar thermoelectric generator with forced convection cooling

    NASA Astrophysics Data System (ADS)

    Sundarraj, Pradeepkumar; Taylor, Robert A.; Banerjee, Debosmita; Maity, Dipak; Sinha Roy, Susanta

    2017-01-01

    Hybrid solar thermoelectric generators (HSTEGs) have garnered significant research attention recently due to their potential ability to cogenerate heat and electricity. In this paper, theoretical and experimental investigations of the electrical and thermal performance of a HSTEG system are reported. In order to validate the theoretical model, a laboratory scale HSTEG system (based on forced convection cooling) is developed. The HSTEG consists of six thermoelectric generator modules, an electrical heater, and a stainless steel cooling block. Our experimental analysis shows that the HSTEG is capable of producing a maximum electrical power output of 4.7 W, an electrical efficiency of 1.2% and thermal efficiency of 61% for an average temperature difference of 92 °C across the TEG modules with a heater power input of 382 W. These experimental results of the HSTEG system are found to be in good agreement with the theoretical prediction. This experimental/theoretical analysis can also serve as a guide for evaluating the performance of the HSTEG system with forced convection cooling.

  7. 300 WATT PORTABLE THERMOELECTRIC GENERATOR.

    DTIC Science & Technology

    GENERATORS , *ELECTRIC POWER PRODUCTION, POWER SUPPLIES, THERMOELECTRICITY, THERMOELECTRICITY, PORTABLE EQUIPMENT, THERMOCOUPLES, ENERGY CONVERSION, LIFE EXPECTANCY(SERVICE LIFE), HEAT TRANSFER, VOLTAGE REGULATORS.

  8. 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.

  9. 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.

  10. Concentrated Solar Thermoelectric Power

    SciTech Connect

    Chen, Gang; Ren, Zhifeng

    2015-07-09

    The goal of this project is to demonstrate in the lab that solar thermoelectric generators (STEGs) can exceed 10% solar-to-electricity efficiency, and STEGs can be integrated with phase-change materials (PCM) for thermal storage, providing operation beyond daylight hours. This project achieved significant progress in many tasks necessary to achieving the overall project goals. An accurate Themoelectric Generator (TEG) model was developed, which included realistic treatment of contact materials, contact resistances and radiative losses. In terms of fabricating physical TEGs, high performance contact materials for skutterudite TE segments were developed, along with brazing and soldering methods to assemble segmented TEGs. Accurate measurement systems for determining device performance (in addition to just TE material performance) were built for this project and used to characterize our TEGs. From the optical components’ side, a spectrally selective cermet surface was developed with high solar absorptance and low thermal emittance, with thermal stability at high temperature. A measurement technique was also developed to determine absorptance and total hemispherical emittance at high temperature, and was used to characterize the fabricated spectrally selective surfaces. In addition, a novel reflective cavity was designed to reduce radiative absorber losses and achieve high receiver efficiency at low concentration ratios. A prototype cavity demonstrated that large reductions in radiative losses were possible through this technique. For the overall concentrating STEG system, a number of devices were fabricated and tested in a custom built test platform to characterize their efficiency performance. Additionally, testing was performed with integration of PCM thermal storage, and the storage time of the lab scale system was evaluated. Our latest testing results showed a STEG efficiency of 9.6%, indicating promising potential for high performance concentrated STEGs.

  11. 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.

  12. GROUND POWER THERMOELECTRIC GENERATOR INVESTIGATION.

    DTIC Science & Technology

    GENERATORS), (*THERMOELECTRICITY, SEEBECK EFFECT , MANUFACTURING, MATERIALS, TELLURIUM, STRESSES, COPPER, STAINLESS STEEL, ELECTRON BEAM WELDING, TITANIUM, POWER, TEMPERATURE, LEAD COMPOUNDS, TELLURIDES.

  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. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Solar thermoelectricity via advanced latent heat storage

    NASA Astrophysics Data System (ADS)

    Olsen, M. L.; Rea, J.; Glatzmaier, G. C.; Hardin, C.; Oshman, C.; Vaughn, J.; Roark, T.; Raade, J. W.; Bradshaw, R. W.; Sharp, J.; Avery, A. D.; Bobela, D.; Bonner, R.; Weigand, R.; Campo, D.; Parilla, P. A.; Siegel, N. P.; Toberer, E. S.; Ginley, D. S.

    2016-05-01

    We report on a new modular, dispatchable, and cost-effective solar electricity-generating technology. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) integrates several state-of-the-art technologies to provide electricity on demand. In the envisioned STEALS system, concentrated sunlight is converted to heat at a solar absorber. The heat is then delivered to either a thermoelectric (TE) module for direct electricity generation, or to charge a phase change material for thermal energy storage, enabling subsequent generation during off-sun hours, or both for simultaneous electricity production and energy storage. The key to making STEALS a dispatchable technology lies in the development of a "thermal valve," which controls when heat is allowed to flow through the TE module, thus controlling when electricity is generated. The current project addresses each of the three major subcomponents, (i) the TE module, (ii) the thermal energy storage system, and (iii) the thermal valve. The project also includes system-level and techno- economic modeling of the envisioned integrated system and will culminate in the demonstration of a laboratory-scale STEALS prototype capable of generating 3kWe.

  4. Solar Thermoelectricity via Advanced Latent Heat Storage

    SciTech Connect

    Olsen, Michele L.; Rea, J.; Glatzmaier, Greg C.; Hardin, C.; Oshman, C.; Vaughn, J.; Roark, T.; Raade, J. W.; Bradshaw, R. W.; Sharp, J.; Avery, Azure D.; Bobela, David; Bonner, R.; Weigand, R.; Campo, D.; Parilla, Philip A.; Siegel, N. P.; Toberer, Eric S.; Ginley, David S.

    2016-05-31

    We report on a new modular, dispatchable, and cost-effective solar electricity-generating technology. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) integrates several state-of-the-art technologies to provide electricity on demand. In the envisioned STEALS system, concentrated sunlight is converted to heat at a solar absorber. The heat is then delivered to either a thermoelectric (TE) module for direct electricity generation, or to charge a phase change material for thermal energy storage, enabling subsequent generation during off-sun hours, or both for simultaneous electricity production and energy storage. The key to making STEALS a dispatchable technology lies in the development of a 'thermal valve,' which controls when heat is allowed to flow through the TE module, thus controlling when electricity is generated. The current project addresses each of the three major subcomponents, (i) the TE module, (ii) the thermal energy storage system, and (iii) the thermal valve. The project also includes system-level and techno- economic modeling of the envisioned integrated system and will culminate in the demonstration of a laboratory-scale STEALS prototype capable of generating 3kWe.

  5. Development of Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric Cryocooling Devices

    DTIC Science & Technology

    2015-05-12

    nanofabrication to develop nanostructured thermoelectric (TE) materials for application in high-efficiency thermoelectric power generators and solid...Distribution Unlimited Final Report: Development of Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric...Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric Cryocooling Devices Report Title The research

  6. PHOTOVOLTAIC AND THERMOELECTRIC SOLAR ENERGY CONVERSION USING THIN FILMS,

    DTIC Science & Technology

    Solar energy conversion by the use of thin films in photovoltaic and thermoelectric devices is discussed. Experimental work is presented on the fabrication of a thin film cadmium sulfide cell which utilizes the photovoltaic effect. A theoretical investigation is made of the temperature differences obtainable in space by using thin, light-weight plastic sheets, and the use of such plastics for thermoelectric generators is discussed. Temperature differences of several hundred centrigrade degrees can be obtained. (Author)

  7. Hybrid thermoelectric solar collector design and analysis

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  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 Design in Dynamic Thermoelectric Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Kiziroglou, M. E.; Becker, Th; Wright, S. W.; Yeatman, E. M.; Evans, J. W.; Wright, P. K.

    2016-11-01

    This paper reports an analysis of thermoelectric generator design for dynamic thermoelectric harvesting. In such devices, the available energy for a given temperature cycle is finite and determined by the heat storage unit capacity. It is shown by simulation and experimentally that specific thermoelectric generator designs can increase the energy output, by optimizing the balance between heat leakage and dynamic response delay. A 3D printed, doublewall heat storage unit is developed for the experiments. Output energy of 30 J from 7.5 gr of phase change material, from a temperature cycle between ± 22 °C is demonstrated, enough to supply typical duty-cycled wireless sensor platforms. These results may serve as guidelines for the design and fabrication of dynamic thermoelectric harvesters for applications involving environments with moderate temperature fluctuations.

  10. Catalytic converter with thermoelectric generator

    SciTech Connect

    Parise, R.J.

    1998-07-01

    The unique design of an electrically heated catalyst (EHC) and the inclusion of an ECO valve in the exhaust of an internal combustion engine will meet the strict new emission requirements, especially at vehicle cold start, adopted by several states in this country as well as in Europe and Japan. The catalytic converter (CC) has been a most useful tool in pollution abatement for the automobile. But the emission requirements are becoming more stringent and, along with other improvements, the CC must be improved to meet these new standards. Coupled with the ECO valve, the EHC can meet these new emission limits. In an internal combustion engine vehicle (ICEV), approximately 80% of the energy consumed leaves the vehicle as waste heat: out the tail pipe, through the radiator, or convected/radiated off the engine. Included with the waste heat out the tail pipe are the products of combustion which must meet strict emission requirements. The design of a new CC is presented here. This is an automobile CC that has the capability of producing electrical power and reducing the quantity of emissions at vehicle cold start, the Thermoelectric Catalytic Power Generator. The CC utilizes the energy of the exothermic reactions that take place in the catalysis substrate to produce electrical energy with a thermoelectric generator. On vehicle cold start, the thermoelectric generator is used as a heat pump to heat the catalyst substrate to reduce the time to catalyst light-off. Thus an electrically heated catalyst (EHC) will be used to augment the abatement of tail pipe emissions. Included with the EHC in the exhaust stream of the automobile is the ECO valve. This valve restricts the flow of pollutants out the tail pipe of the vehicle for a specified amount of time until the EHC comes up to operating temperature. Then the ECO valve opens and allows the full exhaust, now treated by the EHC, to leave the vehicle.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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)

  16. Thermoelectric power generator with intermediate loop

    DOEpatents

    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.

  17. 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.

  18. Survey of Thermoelectric and Solar Technologies as Alternative Energy Solutions

    DTIC Science & Technology

    2012-02-01

    the AlGaAs layers on the carrier transport properties , the n-i-p structures should be regrown on p-type GaAs substrates rather than beryllium (Be...thermoelectric power generation, enabling full diurnal operation. This report discusses measurements of the properties and efficiency of a...10 Figure 10. I-V characteristics of solar cells with and without an AlGaAs layer (left) a p-i-n

  19. 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.

  20. High Efficiency Thermoelectric Generator: Integration

    DTIC Science & Technology

    2011-02-25

    included: − material barriers such as thermal blankets, glass bubbles and aerogels , − encapsulation with high molecular weight gases (e.g. Xenon... aerogels impregnated with radiation scattering particles (investigated at the thermoelectric group in the NASA Jet Propulsion Laboratory). Thrust

  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. 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.

  3. 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.

  4. Design and development of thermoelectric generator

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  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. 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.

  7. 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.

  8. Thermoelectric Generators used as Cryogenic Heat Engines

    NASA Astrophysics Data System (ADS)

    Smith, D. E.; Ordonez, C. A.

    1997-03-01

    A future experiment is being planned at the University of North Texas to design, build, and test a cryogenic heat engine(C. A. Ordonez, Am. J. Phys. 64), 479 (1996). suitable as an electric-vehicle power system. The power system shall then be installed in a demonstration vehicle. This will be a next-generation vehicle following the current project described in the accompanying poster, ``Experimental Car Which Uses Liquid Nitrogen as Its Fuel" by M. E. Parker et al. The cryogenic heat engine electric vehicle power system will incorporate both a thermoelectric generator and an ambient-temperature turbine or pneumatic-motor/generator. The thermoelectric generator shall use liquid nitrogen (under pressure) as its cold reservoir. Energy is produced with the thermoelectric generator by using the liquid/gas phase change to absorb heat. At the present time a study is being carried out to determine the efficiency of thermoelectric devices which are used as cryogenic heat engines. Initial data is being taken using frozen H_2O and CO2 as cold reservoirs. The results of the study shall be presented.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Fiber-based flexible thermoelectric power generator

    NASA Astrophysics Data System (ADS)

    Yadav, A.; Pipe, K. P.; Shtein, M.

    Flexible thermoelectric power generators fabricated by evaporating thin films on flexible fiber substrates are demonstrated to be feasible candidates for waste heat recovery. An open circuit voltage of 19.6 μV K per thermocouple junction is measured for Ni-Ag thin films, and a maximum power of 2 nW for 7 couples at Δ T = 6.6 K is measured. Heat transfer analysis is used to project performance for several other material systems, with a predicted power output of 1 μW per couple for Bi 2Te 3/Sb 2Te 3-based fiber coatings with a hot junction temperature of 100 °C. Considering the performance of woven thermoelectric cloths or fiber composites, relevant properties and dimensions of individual thermoelectric fibers are optimized.

  14. Solar Generator

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The Vanguard I dish-Stirling module program, initiated in 1982, produced the Vanguard I module, a commercial prototype erected by the Advanco Corporation. The module, which automatically tracks the sun, combines JPL mirrored concentrator technology, an advanced Stirling Solar II engine/generator, a low cost microprocessor-controlled parabolic dish. Vanguard I has a 28% sunlight to electricity conversion efficiency. If tests continue to prove the system effective, Advanco will construct a generating plant to sell electricity to local utilities. An agreement has also been signed with McDonnell Douglas to manufacture a similar module.

  15. Radioisotope thermoelectric generators for implanted pacemakers

    SciTech Connect

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

    1986-08-01

    This paper discusses the development and application of long-life lithium batteries and the problems associated with miniature radioisotope thermoelectric generators (RITEG) with service lives of 10 years or longer. On eof the main problems encountered when devising a radioisotope heat source (RHS) for an RITEG is to obtain biomedical /sup 238/PuO/sub 2/ with a specific neutron yield of 3.10/sup 3/-4.10/sup 3/ (g /SUP ./ sec)/sup -1/, equivalent to metallic Pu 238, and with a content of gamma impurities sufficient to ensure a permissible exposure a permissible exposure does rate (EDR) of a mixture of neutron and gamma radiation. After carrying out the isotope exchange and purifying the initial sample of its gamma impurity elements, the authors obtain biomedical Pu 238 satisfying the indicated requirements king suitable for use in the power packs of medical devices. Taking the indicated specifications into account, the Ritm-1o and gamma radioisotope heat sources were designed, built, tested in models and under natural conditions, and then into production as radioisotope thermoelectric generators designed to power the electronic circuits of implanted pacemakers. The Ritm-MT and Gemma radioisotope thermoelectric generators described are basic units, which can be used as self-contained power supplies for electronic equipment with power requirements in the micromilliwatt range.

  16. 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.

  17. Potential health risks from postulated accidents involving the Pu-238 RTG (radioisotope thermoelectric generator) on the Ulysses solar exploration mission

    SciTech Connect

    Goldman, M. ); Nelson, R.C. ); Bollinger, L. ); Hoover, M.D. . Inhalation Toxicology Research Inst.); Templeton, W. ); Anspaugh, L. (Lawren

    1990-11-02

    Potential radiation impacts from launch of the Ulysses solar exploration experiment were evaluated using eight postulated accident scenarios. Lifetime individual dose estimates rarely exceeded 1 mrem. Most of the potential health effects would come from inhalation exposures immediately after an accident, rather than from ingestion of contaminated food or water, or from inhalation of resuspended plutonium from contaminated ground. For local Florida accidents (that is, during the first minute after launch), an average source term accident was estimated to cause a total added cancer risk of up to 0.2 deaths. For accidents at later times after launch, a worldwide cancer risk of up to three cases was calculated (with a four in a million probability). Upper bound estimates were calculated to be about 10 times higher. 83 refs.

  18. 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 %.

  19. 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).

  20. Autonomous Underwater Vehicle Thermoelectric Power Generation

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  1. 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.

  2. 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

  3. 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.

  4. Feasibility Study on the Use of a Solar Thermoelectric Cogenerator Comprising a Thermoelectric Module and Evacuated Tubular Collector with Parabolic Trough Concentrator

    NASA Astrophysics Data System (ADS)

    Miao, L.; Zhang, M.; Tanemura, S.; Tanaka, T.; Kang, Y. P.; Xu, G.

    2012-06-01

    We have designed a new solar thermoelectric cogeneration system consisting of an evacuated tubular solar collector (ETSC) with a parabolic trough concentrator (PTC) and thermoelectric modules (TEMs) to supply both thermal energy and electricity. The main design concepts are (1) the hot side of the TEM is bonded to the solar selective absorber installed in an evacuated glass tube, (2) the cold side of the TEM is also bonded to the heat sink, and (3) the outer circulated water is heated by residual solar energy after TEM generation. We present an example solar thermal simulation based on energy balance and heat transfer as used in solar engineering to predict the electrical conversion efficiency and solar thermal conversion efficiency for different values of parameters such as the solar insolation, concentration ratio, and TEM ZT values.

  5. 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.

  6. Structural design and manufacture of high packing density micro-thermoelectric power generators using thermoelectric films

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Jin, Yi-Teng; Zhu, Yan-Bing; Liao, Xia; Xu, Han; Li, Huan; Gao, Jian-Ping

    2011-05-01

    A new micro-thermoelectric power generator module with high packing density of film thermoelectric legs has been proposed, in which a large number of p-type and n-type thin-film thermoelectric legs are electrically connected in series. A theoretical model has been established to simulate the output voltage and power of the proposed module, and the results shows that much higher output voltage and output power can be obtained simply by integrating more film thermoelectric components. Based on the proposed module, a micro-thermoelectric power generator containing 160 film thermocouples is fabricated with a size of 25mm (length) × 4mm (width) × 1mm (thickness). Its open-circuit voltage, maximum output power and corresponding power density at a temperature difference of 20K are 630mV, 35.73μW and 357.3μW·cm-3, respectively.

  7. 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.

  8. 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.

  9. The potential impact of ZT=4 thermoelectric materials on solar thermal energy conversion technologies.

    SciTech Connect

    Xie, M.; Gruen, D. M.; Materials Science Division; Michigan Technological Univ.

    2010-03-02

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

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

    PubMed

    Xie, Ming; Gruen, Dieter M

    2010-11-18

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

  11. Experimental Performance of a Solar Thermoelectric Cogenerator Comprising Thermoelectric Modules and Parabolic Trough Concentrator without Evacuated Tube

    NASA Astrophysics Data System (ADS)

    Miao, L.; Kang, Y. P.; Li, C.; Tanemura, S.; Wan, C. L.; Iwamoto, Y.; Shen, Y.; Lin, H.

    2015-06-01

    A prototype practical solar-thermoelectric cogenerator composed of (1) a primary component of a pile of solar-selective absorber (SSA) slab, thermoelectric (TE) modules, and a depressed water flow tube (multichannel cooling heat sink, MCS), and (2) a parabolic trough concentrator with aperture area of 2m × 2m and east-west focal axis was constructed. Its cogeneration performance under the best climatic and solar insolation conditions in Guangzhou, China was tested. For simplicity, the evacuated glass tube to cover the primary component was eliminated from the system. Six Bi2Te3 TE modules were arranged in series, directly bonded to the rear surface of the solar absorber slab. The hot-side temperature of the TE module reached up to 152°C. The experimentally obtained instantaneous results for the solar to electrical conversion efficiency, heat exchange coefficient of the MCS, and overall system efficiency under the best environmental and solar insolation conditions were about 1.14%, 56.1%, and 49.5%, respectively. To justify these values, an equivalent thermal network diagram based on a single-temperature-node heat transfer model representing the respective system components was used to analyze the thermal transfer and losses of the system. Finally, electrical power of 18° W was generated, with 2 L/min of hot water at 37°C being produced and stored in the insulated container.

  12. Optimal Number of Thermoelectric Couples in a Heat Pipe Assisted Thermoelectric Generator for Waste Heat Recovery

    NASA Astrophysics Data System (ADS)

    Liu, Tongjun; Wang, Tongcai; Luan, Weiling; Cao, Qimin

    2017-01-01

    Waste heat recovery through thermoelectric generators is a promising way to improve energy conversion efficiency. This paper proposes a type of heat pipe assisted thermoelectric generator (HP-TEG) system. The expandable evaporator and condenser surface of the heat pipe facilitates the intensive assembly of thermoelectric (TE) modules to compose a compact device. Compared with a conventional layer structure thermoelectric generator, this system is feasible for the installment of more TE couples, thus increasing power output. To investigate the performance of the HP-TEG and the optimal number of TE couples, a theoretical model was presented and verified by experiment results. Further theoretical analysis results showed the performance of the HP-TEG could be further improved by optimizing the parameters, including the inlet air temperature, the thermal resistance of the heating section, and thermal resistance of the cooling structure. Moreover, applying a proper number of TE couples is important to acquire the best power output performance.

  13. Solar energy conversion with tunable plasmonic nanostructures for thermoelectric devices.

    PubMed

    Xiong, Yujie; Long, Ran; Liu, Dong; Zhong, Xiaolan; Wang, Chengming; Li, Zhi-Yuan; Xie, Yi

    2012-08-07

    The photothermal effect in localized surface plasmon resonance (LSPR) should be fully utilized when integrating plasmonics into solar technologies for improved light absorption. In this communication, we demonstrate that the photothermal effect of silver nanostructures can provide a heat source for thermoelectric devices for the first time. The plasmonic band of silver nanostructures can be facilely manoeuvred by tailoring their shapes, enabling them to interact with photons in different spectral ranges for the efficient utilization of solar light. It is anticipated that this concept can be extended to design a photovoltaic-thermoelectric tandem cell structure with plasmonics as mediation for light harvesting.

  14. Thermoelectric Power Generation System Using Waste Heat from Biomass Drying

    NASA Astrophysics Data System (ADS)

    Maneewan, S.; Chindaruksa, S.

    2009-07-01

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

  15. State of the art in solar thermoelectric power plant research

    NASA Astrophysics Data System (ADS)

    Etievant, C.

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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Thermoelectric generator and method for the fabrication thereof

    DOEpatents

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

    1984-08-01

    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 as thermoelectric generators.

  1. Solar energy conversion with tunable plasmonic nanostructures for thermoelectric devices

    NASA Astrophysics Data System (ADS)

    Xiong, Yujie; Long, Ran; Liu, Dong; Zhong, Xiaolan; Wang, Chengming; Li, Zhi-Yuan; Xie, Yi

    2012-07-01

    The photothermal effect in localized surface plasmon resonance (LSPR) should be fully utilized when integrating plasmonics into solar technologies for improved light absorption. In this communication, we demonstrate that the photothermal effect of silver nanostructures can provide a heat source for thermoelectric devices for the first time. The plasmonic band of silver nanostructures can be facilely manoeuvred by tailoring their shapes, enabling them to interact with photons in different spectral ranges for the efficient utilization of solar light. It is anticipated that this concept can be extended to design a photovoltaic-thermoelectric tandem cell structure with plasmonics as mediation for light harvesting.The photothermal effect in localized surface plasmon resonance (LSPR) should be fully utilized when integrating plasmonics into solar technologies for improved light absorption. In this communication, we demonstrate that the photothermal effect of silver nanostructures can provide a heat source for thermoelectric devices for the first time. The plasmonic band of silver nanostructures can be facilely manoeuvred by tailoring their shapes, enabling them to interact with photons in different spectral ranges for the efficient utilization of solar light. It is anticipated that this concept can be extended to design a photovoltaic-thermoelectric tandem cell structure with plasmonics as mediation for light harvesting. Electronic supplementary information (ESI) available: Detailed experimental procedures. See DOI: 10.1039/c2nr30208j

  2. 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.

  3. 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.

  4. 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.

  5. Thermoelectric power generator for variable thermal power source

    DOEpatents

    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.

  6. Power Conditioner with Variable Switching Control for Thermoelectric Generator Systems

    NASA Astrophysics Data System (ADS)

    Nagayoshi, Hiroshi; Maiwa, Hiroshi; Kajikawa, Takenobu

    2013-07-01

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

  7. Portable Power Generation via Integrated Catalytic Microcombustion-Thermoelectric Devices

    DTIC Science & Technology

    2004-12-01

    PORTABLE POWER GENERATION VIA INTEGRATED CATALYTIC MICROCOMBUSTION-THERMOELECTRIC DEVICES D. G. Norton, K. W. Voit, T. Brüggemann, and D. G...resulting in electrical power generation from catalytic microcombustion with a thermal efficiency of ~1%. 1. INTRODUCTION Advances in soldier...environmental burdens. Power generation utilizing hydrocarbons offers a promising alternative to traditional batteries. The energy density of

  8. Theoretical Approach to Predict the Performance of Thermoelectric Generator Modules

    NASA Astrophysics Data System (ADS)

    Elarusi, Abdulmunaem H.; Fagehi, Hassan; Lee, Hosung; Attar, Alaa

    2017-02-01

    The aim of this work was to examine the validity of the thermoelectric modules' performance predicted by formulating the effective thermoelectric material properties. The three maximum parameters (output power, current, and efficiency) are defined in terms of the average temperature of the thermoelectric generator (TEG). These three maximum parameters, which are either taken from commercial TEG modules or measurements for particular operating conditions, are used to define the effective material properties (Seebeck coefficient, thermal conductivity, and electrical resistivity). The commercial performance curves provided by the manufacturer were compared with the results obtained here by the effective material properties with the simple standard thermoelectric equations. It has been found that this technique predicts the performance of four commercial thermoelectric modules with fair to good accuracy. The characteristics of the TEGs were represented using the normalized charts constructed by formulating the parameters as a fraction of over the maximum parameters. The normalized charts would be universal for any given TEG module once the thermoelectric material is known.

  9. New thermoelectric materials and devices for terrestrial power generators

    NASA Astrophysics Data System (ADS)

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

    1997-01-01

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

  10. 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.

  11. Parametric Optimization of Thermoelectric Generators for Waste Heat Recovery

    NASA Astrophysics Data System (ADS)

    Huang, Shouyuan; Xu, Xianfan

    2016-10-01

    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.

  12. Performance Analysis of a Thermoelectric Solar Collector Integrated with a Heat Pump

    NASA Astrophysics Data System (ADS)

    Lertsatitthanakorn, C.; Jamradloedluk, J.; Rungsiyopas, M.; Therdyothin, A.; Soponronnarit, S.

    2013-07-01

    A novel heat pump system is proposed. A thermoelectric solar collector was coupled to a solar-assisted heat pump (TESC-HP) to work as an evaporator. The cooling effect of the system's refrigerant allowed the cold side of the system's thermoelectric modules to work at lower temperature, improving the conversion efficiency. The TESC-HP system mainly consisted of transparent glass, an air gap, an absorber plate that acted as a direct expansion-type collector/evaporator, an R-134a piston-type hermetic compressor, a water-cooled plate-type condenser, thermoelectric modules, and a water storage tank. Test results indicated that the TESC-HP has better coefficient of performance (COP) and conversion efficiency than the separate units. For the meteorological conditions in Mahasarakham, the COP of the TESC-HP system can reach 5.48 when the average temperature of 100 L of water is increased from 28°C to 40°C in 60 min with average ambient temperature of 32.5°C and average solar intensity of 815 W/m2, whereas the conversion efficiency of the TE power generator was around 2.03%.

  13. 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.

  14. Thermoelectric Materials Development for Low Temperature Geothermal Power Generation

    SciTech Connect

    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.

  15. Thermochemical solar hydrogen generation.

    PubMed

    Licht, Stuart

    2005-10-07

    Solar direct, indirect and hybrid thermochemical processes are presented for the generation of hydrogen and compared to alternate solar hydrogen processes. A hybrid solar thermal/electrochemical process combines efficient photovoltaics and concentrated excess sub-bandgap heat into highly efficient elevated temperature solar electrolysis of water and generation of H2 fuel utilizing the thermodynamic temperature induced decrease of E(H2O) with increasing temperature. Theory and experiment is presented for this process using semiconductor bandgap restrictions and combining photodriven charge transfer, with excess sub-bandgap insolation to lower the water potential, and their combination into highly efficient solar generation of H2 is attainable. Fundamental water thermodynamics and solar photosensitizer constraints determine solar energy to hydrogen fuel conversion efficiencies in the 50% range over a wide range of insolation, temperature, pressure and photosensitizer bandgap conditions.

  16. 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.

  17. 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.

  18. 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.

  19. Solar fuels generator

    DOEpatents

    Lewis, Nathan S.; Spurgeon, Joshua M.

    2016-10-25

    The solar fuels generator includes an ionically conductive separator between a gaseous first phase and a second phase. A photoanode uses one or more components of the first phase to generate cations during operation of the solar fuels generator. A cation conduit is positioned provides a pathway along which the cations travel from the photoanode to the separator. The separator conducts the cations. A second solid cation conduit conducts the cations from the separator to a photocathode.

  20. 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.

  1. 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.

  2. 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.

  3. Performance Study of a Double-Pass Thermoelectric Solar Air Collector with Flat-Plate Reflectors

    NASA Astrophysics Data System (ADS)

    Lertsatitthanakorn, C.; Rungsiyopas, M.; Therdyothin, A.; Soponronnarit, S.

    2012-06-01

    In this paper the results of the influence of flat-plate reflectors made of aluminum foil on the performance of a double-pass thermoelectric (TE) solar air collector are presented. The proposed TE solar collector with reflectors was composed of transparent glass, an air gap, an absorber plate, TE modules, a rectangular fin heat sink, and two flat-plate reflectors. The flat-plate reflectors were placed on two sides of the TE solar collector (east and west directions). The TE solar collector was installed on a one-axis sun-tracking system to obtain high solar radiation. Direct and reflected incident solar radiation heats up the absorber plate so that a temperature difference is created across the TE modules to generate a direct current. Only a small part of the absorbed solar radiation is converted to electricity, while the rest increases the temperature of the absorber plate. Ambient air flows through the heat sink located in the lower channel to gain heat. The heated air then flows to the upper channel, where it receives additional heating from the absorber plate. Improvements to the thermal energy and electrical power outputs of the system can be achieved by the use of the double-pass collector system with reflectors and TE technology. It was found that the optimum position of the reflectors is 60°, which gave significantly higher thermal energy and electrical power outputs compared with the TE solar collector without reflectors.

  4. 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.

  5. 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.

  6. 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.

  7. Improving power density and efficiency of miniature radioisotopic thermoelectric generators

    NASA Astrophysics Data System (ADS)

    Whalen, Scott A.; Apblett, Christopher A.; Aselage, Terrence L.

    We have built and tested a prototype miniaturized thermoelectric power source that generates 450 μW of electrical power in a system volume of 4.3 cm 3. The measured power density of 104 μW cm -3 exceeds that of any previously reported thermoelectric power system of equivalent size. This improvement was achieved by implementing a novel thermopile design in which wagon wheel-shaped thermoelectric elements contact the entire circumference of the heat source whereas traditional approaches utilize only one heat source surface. The thermopile consists of 22 wagon wheel-shaped elements (11 P-N thermocouples) fabricated from 215-μm thick bismuth-telluride wafers having ZT = 0.97 at 30 °C. The power source operates on a 150 mW thermal input provided by an electrical resistance heater that simulates a capsule containing 0.4 g of 238PuO 2 located at the center of the device. Our primary research objective was to develop and demonstrate a prototype thermopile and radioisotopic thermoelectric generator (RTG) architecture with improved power density at small scales. Output power from this device, while optimized for efficiency, was not optimized for output voltage, and the maximum power was delivered at 41 mV. We also discuss modifications to our prototype design that result in significantly improved voltage and power. Numerical predictions show that a power output of 1.4 mW, power density of 329 μW cm -3, and voltage of 362 mV, is possible in the same package size.

  8. 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.

  9. 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

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

    PubMed

    Arab, Abbas; Li, Qiliang

    2015-09-03

    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.

  11. Usage of Multi-Mission Radioisotope Thermoelectric Generators (MMRTGs) for Future Potential Missions

    NASA Technical Reports Server (NTRS)

    Zakrajsek, June F.; Cairns-Gallimore, Dirk; Otting, Bill; Johnson, Steve; Woerner, Dave

    2016-01-01

    The goal of NASAs Radioisotope Power Systems (RPS) Program is to make RPS ready and available to support the exploration of the solar system in environments where the use of conventional solar or chemical power generation is impractical or impossible to meet the needs of the missions. To meet this goal, the RPS Program, working closely with the Department of Energy, performs mission and system studies (such as the recently released Nuclear Power Assessment Study), evaluates the readiness of promising technologies to infuse in future generators, assesses the sustainment of key RPS capabilities and knowledge, forecasts and tracks the Programs budgetary needs, and disseminates current information about RPS to the community of potential users. This presentation focuses on the needs of the mission community and provides users a better understanding of how to integrate the MMRTG (Multi-Mission Radioisotope Thermoelectric Generator).

  12. Solar Fuel Generator

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor); West, William C. (Inventor)

    2017-01-01

    The disclosure provides conductive membranes for water splitting and solar fuel generation. The membranes comprise an embedded semiconductive/photoactive material and an oxygen or hydrogen evolution catalyst. Also provided are chassis and cassettes containing the membranes for use in fuel generation.

  13. Solar fuel generator

    DOEpatents

    Lewis, Nathan S.; West, William C.

    2017-01-17

    The disclosure provides conductive membranes for water splitting and solar fuel generation. The membranes comprise an embedded semiconductive/photoactive material and an oxygen or hydrogen evolution catalyst. Also provided are chassis and cassettes containing the membranes for use in fuel generation.

  14. 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

  15. 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.

  16. 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.

  17. Modular Analysis of Automobile Exhaust Thermoelectric Power Generation System

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  18. Flexible thermoelectric generator for ambient assisted living wearable biometric sensors

    NASA Astrophysics Data System (ADS)

    Francioso, L.; De Pascali, C.; Farella, I.; Martucci, C.; Cretì, P.; Siciliano, P.; Perrone, A.

    2011-03-01

    In this work we proposed design, fabrication and functional characterization of a very low cost energy autonomous, maintenance free, flexible and wearable micro thermoelectric generator (μTEG), finalized to power very low consumption electronics ambient assisted living (AAL) applications. The prototype, integrating an array of 100 thin films thermocouples of Sb2Te3 and Bi2Te3, generates, at 40 °C, an open circuit output voltage of 430 mV and an electrical output power up to 32 nW with matched load. In real operation conditions of prototype, which are believed to be very close to a thermal gradient of 15 °C, the device generates an open circuit output voltage of about 160 mV, with an electrical output power up to 4.18 nW. In the first part of work, deposition investigation Sb2Te3 and Bi2Te3 thin films alloys on Kapton HN polyimide foil by RF magnetron co-sputtering technique is discussed. Deposition parameters have been optimized to gain perfect stoichiometric ratio and high thermoelectric power factor; fabricated thermogenerator has been tested at low gradient conditioned to evaluate applications like human skin wearable power generator for ambient assisted living applications.

  19. 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.

  20. 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.

  1. 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.}

  2. 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.

  3. 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.

  4. Optimized Characterization of Thermoelectric Generators for Automotive Application

    NASA Astrophysics Data System (ADS)

    Tatarinov, Dimitri; Wallig, Daniel; Bastian, Georg

    2012-06-01

    New developments in the field of thermoelectric materials bring the prospect of consumer devices for recovery of some of the waste heat from internal combustion engines closer to reality. Efficiency improvements are expected due to the development of high-temperature thermoelectric generators (TEG). In contrast to already established radioisotope thermoelectric generators, the temperature difference in automotive systems is not constant, and this imposes a set of specific requirements on the TEG system components. In particular, the behavior of the TEGs and interface materials used to link the heat flow from the heat source through the TEG to the heat sink must be examined. Due to the usage patterns of automobiles, the TEG will be subject to cyclic thermal loads, which leads to module degradation. Additionally, the automotive TEG will be exposed to an inhomogeneous temperature distribution, leading to inhomogeneous mechanical loads and reduced system efficiency. Therefore, a characterization rig is required to allow determination of the electrical, thermal, and mechanical properties of such high-temperature TEG systems. This paper describes a measurement setup using controlled adjustment of cold-side and warm-side temperatures as well as controlled feed-in of electrical power for evaluation of TEGs for application in vehicles with combustion engines. The temperature profile in the setup can be varied to simulate any vehicle usage pattern, such as the European standard driving cycle, allowing the power yield of the TEGs to be evaluated for the chosen cycle. The spatially resolved temperature distribution of a TEG system can be examined by thermal imaging. Hotspots or cracks on thermocouples of the TEGs and the thermal resistance of thermal interface materials can also be examined using this technology. The construction of the setup is briefly explained, followed by detailed discussion of the experimental results.

  5. 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

  6. Simulation, design and fabrication of a planar micro thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Pelegrini, S.; Adami, A.; Collini, C.; Conci, P.; Lorenzelli, L.; Pasa, A. A.

    2013-05-01

    This study describes the design, simulation, and micro fabrication of a micro thermoelectric generator (μTEG) based on planar technology using constantan (CuNi) and copper (Cu) thermocouples deposited electrochemically (ECD) on silicon substrate. The present thin film technology can be manufactured into large area and also on flexible substrate with low cost of production and can be used to exploit waste heat from equipments or hot surfaces in general. In the current implementation, the silicon structure has been designed and optimized with analytical models and FE simulations in order to exploit the different thermal conductivity of silicon and air gaps to produce the maximum temperature difference on a planar surface. The results showed that a temperature difference of 10K across the structure creates a temperature difference of 5.3K on the thermocouples, thus providing an efficiency of thermal distribution up to 55%, depending on the heat convection at the surface. Efficiency of module has been experimentally tested under different working condition, showing the dependence of module output on the external heat exchange (natural and forced convection). Maximum generated potential at 6m/s airflow is 5.7V/m2 K and thermoelectric efficiency is 1.9μW K-2 m-2.

  7. 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.

  8. Hybrid photovoltaic-thermoelectric system for concentrated solar energy conversion: Experimental realization and modeling

    NASA Astrophysics Data System (ADS)

    Beeri, Ofer; Rotem, Oded; Hazan, Eden; Katz, Eugene A.; Braun, Avi; Gelbstein, Yaniv

    2015-09-01

    An experimental demonstration of the combined photovoltaic (PV) and thermoelectric conversion of concentrated sunlight (with concentration factor, X, up to ˜300) into electricity is presented. The hybrid system is based on a multi-junction PV cell and a thermoelectric generator (TEG). The latter increases the electric power of the system and dissipates some of the excessive heat. For X ≤ 200, the system's maximal efficiency, ˜32%, was mostly due to the contribution from the PV cell. With increasing X and system temperature, the PV cell's efficiency decreased while that of the TEG increased. Accordingly, the direct electrical contribution of the TEG started to dominate in the total system power, reaching ˜20% at X ≈ 290. Using a simple steady state finite element modeling, the cooling effect of the TEG on the hybrid system's efficiency was proved to be even more significant than its direct electrical contribution for high solar concentrations. As a result, the total efficiency contribution of the TEG reached ˜40% at X ≈ 200. This suggests a new system optimization concept that takes into account the PV cell's temperature dependence and the trade-off between the direct electrical generation and cooling capabilities of the TEG. It is shown that the hybrid system has a real potential to exceed 50% total efficiency by using more advanced PV cells and TE materials.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Metal-Semiconductor Nanocomposites for High Efficiency Thermoelectric Power Generation

    DTIC Science & Technology

    2013-12-07

    the modified phonon and alloy scattering parameters in the modeling to explain the thermoelectric properties of this material. For example, we...near future. 2. Cross-plane thermoelectric properties of perovskite oxide metal/semiconductor superlattices ( Purdue /UCSC) The cross-plane...It therefore became critical that Purdue optimize this characterization technique to extract material properties which show the potential of metal

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. Cost-Efficiency Trade-off and the Design of Thermoelectric Power Generators

    SciTech Connect

    Yazawa, Kazuaki; Shakouri, Ali

    2011-07-27

    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.

  9. 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.

  10. Solar thermal electricity generation

    NASA Astrophysics Data System (ADS)

    Gasemagha, Khairy Ramadan

    1993-01-01

    This report presents the results of modeling the thermal performance and economic feasibility of large (utility scale) and small solar thermal power plants for electricity generation. A number of solar concepts for power systems applications have been investigated. Each concept has been analyzed over a range of plant power ratings from 1 MW(sub e) to 300 MW(sub e) and over a range of capacity factors from a no-storage case (capacity factor of about 0.25 to 0.30) up to intermediate load capacity factors in the range of 0.46 to 0.60. The solar plant's economic viability is investigated by examining the effect of various parameters on the plant costs (both capital and O & M) and the levelized energy costs (LEC). The cost components are reported in six categories: collectors, energy transport, energy storage, energy conversion, balance of plant, and indirect/contingency costs. Concentrator and receiver costs are included in the collector category. Thermal and electric energy transport costs are included in the energy transport category. Costs for the thermal or electric storage are included in the energy storage category; energy conversion costs are included in the energy conversion category. The balance of plant cost category comprises the structures, land, service facilities, power conditioning, instrumentation and controls, and spare part costs. The indirect/contingency category consists of the indirect construction and the contingency costs. The concepts included in the study are (1) molten salt cavity central receiver with salt storage (PFCR/R-C-Salt); (2) molten salt external central receiver with salt storage (PFCR/R-E-Salt); (3) sodium external central receiver with sodium storage (PFCR/RE-Na); (4) sodium external central receiver with salt storage (PFCR/R-E-Na/Salt); (5) water/steam external central receiver with oil/rock storage (PFCR/R-E-W/S); (6) parabolic dish with stirling engine conversion and lead acid battery storage (PFDR/SLAB); (7) parabolic dish

  11. 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.

  12. Individual Module Maximum Power Point Tracking for Thermoelectric Generator Systems

    NASA Astrophysics Data System (ADS)

    Vadstrup, Casper; Schaltz, Erik; Chen, Min

    2013-07-01

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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Nanowire mesh solar fuels generator

    DOEpatents

    Yang, Peidong; Chan, Candace; Sun, Jianwei; Liu, Bin

    2016-05-24

    This disclosure provides systems, methods, and apparatus related to a nanowire mesh solar fuels generator. In one aspect, a nanowire mesh solar fuels generator includes (1) a photoanode configured to perform water oxidation and (2) a photocathode configured to perform water reduction. The photocathode is in electrical contact with the photoanode. The photoanode may include a high surface area network of photoanode nanowires. The photocathode may include a high surface area network of photocathode nanowires. In some embodiments, the nanowire mesh solar fuels generator may include an ion conductive polymer infiltrating the photoanode and the photocathode in the region where the photocathode is in electrical contact with the photoanode.

  19. Solar Thermal Electricity Generating System

    NASA Astrophysics Data System (ADS)

    Mishra, Sambeet; Tripathy, Pratyasha

    2012-08-01

    A Solar Thermal Electricity generating system also known as Solar Thermal Power plant is an emerging renewable energy technology, where we generate the thermal energy by concentrating and converting the direct solar radiationat medium/high temperature (300∫C ñ 800∫C). The resulting thermal energy is then used in a thermodynamic cycleto produce electricity, by running a heat engine, which turns a generator to make electricity. Solar thermal power is currently paving the way for the most cost-effective solar technology on a large scale and is heading to establish a cleaner, pollution free and secured future. Photovoltaic (PV) and solar thermal technologies are two main ways of generating energy from the sun, which is considered the inexhaustible source of energy. PV converts sunlight directly into electricity whereas in Solar thermal technology, heat from the sun's rays is concentrated to heat a fluid, whose steam powers a generator that produces electricity. It is similar to the way fossil fuel-burning power plants work except that the steam is produced by the collected heat rather than from the combustion of fossil fuels. In order to generate electricity, five major varieties of solar thermal technologies used are:* Parabolic Trough Solar Electric Generating System (SEGS).* Central Receiver Power Plant.* Solar Chimney Power Plant.* Dish Sterling System.* Solar Pond Power Plant.Most parts of India,Asia experiences a clear sunny weather for about 250 to 300 days a year, because of its location in the equatorial sun belt of the earth, receiving fairly large amount of radiation as compared to many parts of the world especially Japan, Europe and the US where development and deployment of solar technologies is maximum.Whether accompanied with this benefit or not, usually we have to concentrate the solar radiation in order to compensate for the attenuation of solar radiation in its way to earthís surface, which results in from 63,2 GW/m2 at the Sun to 1 kW/m2 at

  20. Solar power generation and distribution

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The production of electricity from solar energy is discussed. The economics of the proposed generation and distribution systems are analyzed. The use of photovoltaics for converting solar energy to home heating is proposed. The problems of energy distribution are analyzed from the standpoint of equipment costs and complexity.

  1. 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.

  2. The influence of Thomson effect on the maximum power output and maximum efficiency of a thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Chen, Jincan; Yan, Zijun; Wu, Liqing

    1996-06-01

    Considering a thermoelectric generator as a heat engine cycle, the general differential equations of the temperature field inside thermoelectric elements are established by means of nonequilibrium thermodynamics. These equations are used to study the influence of heat leak, Joule's heat, and Thomson heat on the performance of the thermoelectric generator. New expressions are derived for the power output and the efficiency of the thermoelectric generator. The maximum power output is calculated and the optimal matching condition of load is determined. The maximum efficiency is discussed by a representative numerical example. The aim of this research is to provide some novel conclusions and redress some errors existing in a related investigation.

  3. 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.

  4. A thermo-electric system using concentrated solar energy with photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Wong, K.-F. V.; Dorney, S.

    The work reported here is a preliminary study of a thermo-electric system using concentrated solar radiation with photovoltaic cells. The system incorporated a novel concentrating system with the designed purpose of utilizing those portions of the solar spectrum that the silicon solar cells were not responsive to. The experimental set-up consisted of a 3.8 cm diameter glass tube, 76.2 cm long with the glass silicon cells positioned at equal intervals on its underside. Fresnel lenses were placed so that the incoming solar radiation was concentrated onto the silicon cells. The glass tube was filled with water which absorbed energy from the solar radiation before it reached the cells. The water had its temperature raised nine degrees Fahrenheit while also allowing the solar cells to produce approximately 0.05 watt. This results in an efficiency of around 35 percent. The results obtained are preliminary, and represent typical conditions in south Florida.

  5. 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.

  6. Space Station Freedom solar dynamic power generation

    NASA Technical Reports Server (NTRS)

    Springer, T.; Friefeld, Jerry M.

    1990-01-01

    Viewgraphs on Space Station Freedom solar dynamic power generation are presented. Topics covered include: prime contract activity; key solar dynamic power module requirements; solar dynamic heat receiver technology; and solar concentrator advanced development.

  7. 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.

  8. Selecting the optimum method of heat transfer intensification to improve efficiency of thermoelectric generator

    NASA Astrophysics Data System (ADS)

    Leontyev, A. I.; Onishchenko, D. O.; Arutyunyan, G. A.

    2016-09-01

    The relevance of applying the methods of energy recovery from exhaust gases is substantiated. The principle of operation of a thermoelectric generator is described, the variant of its design is proposed, and the efficiency of various design methods of heat exchange intensification is compared. Designs are compared with a baseline configuration without heat transfer intensifiers in terms of coefficients of gas dynamic resistance ξ/ξ0 and the ratio of dimensionless criteria Nu/Nu0. The results of comparative analysis have proved the applicability of the methods of heat exchange intensification in the design of thermoelectric generators of various vehicles.

  9. 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.

  10. 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.

  11. 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).

  12. 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.

  13. Independent Power Generation in a Modern Electrical Substation Based on Thermoelectric Technology

    NASA Astrophysics Data System (ADS)

    Li, Z. M.; Zhao, Y. Q.; Liu, W.; Wei, B.; Qiu, M.; Lai, X. K.

    2016-10-01

    Because of many types of electrical equipment with high power in substations, the potentiality of energy conservation is quite large. From this viewpoint, thermoelectric materials may be chosen to produce electrical energy using the waste heat produced in substations. Hence, a thermoelectric generation system which can recycle the waste heat from electric transformers was proposed to improve the energy efficiency and reduce the burden of the oil cooling system. An experimental prototype was fabricated to perform the experiment and to verify the feasibility. The experimental results showed that the output power could achieve 16 W from waste heat of 900 W, and that the power conversion efficiency was approximately 1.8%. Therefore, power generation is feasible by using the waste heat from the transformers based on thermoelectric technology.

  14. 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.

  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. 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.

  17. Solar Power Generation Development

    SciTech Connect

    Robert L. Johnson Jr.; Gary E. Carver

    2011-10-28

    This project centered on creating a solar cell prototype enabling significant reductions in module cost and increases in module efficiency. Low cost was addressed by using plentiful organic materials that only comprise 16% of the total module cost, and by leveraging building integrated PV concepts that reduce the cost of key module components to zero. High efficiency was addressed by implementing multiband organic PV, low cost spectral splitting, and possibly integrating photovoltaic and photothermal mechanisms. This research has contributed to the design of multiband organic PV, and the sealing of organic PV cells. If one assumes that the aggregate multiband efficiency can reach 12%, projected cost would be $0.97/W. If the sealing technology enables 10 to 20 year lifetimes, the LCOE will match that of domestic coal. The final report describes progress towards these goals.

  18. Utility Solar Generation Valuation Methods

    SciTech Connect

    Hansen, Thomas N.; Dion, Phillip J.

    2009-06-30

    Tucson Electric Power (TEP) developed, tested and verified the results of a new and appropriate method for accurately evaluating the capacity credit of time variant solar generating sources and reviewed new methods to appropriately and fairly evaluate the value of solar generation to electric utilities. The project also reviewed general integrated approaches for adequately compensating owners of solar generation for their benefits to utilities. However, given the limited funding support and time duration of this project combined with the significant differences between utilities regarding rate structures, solar resource availability and coincidence of solar generation with peak load periods, it is well beyond the scope of this project to develop specific rate, rebate, and interconnection approaches to capture utility benefits for all possible utilities. The project developed computer software based evaluation method models to compare solar generation production data measured in very short term time increments called Sample Intervals over a typical utility Dispatch Cycle during an Evaluation Period against utility system load data. Ten second resolution generation production data from the SGSSS and actual one minute resolution TEP system load data for 2006 and 2007, along with data from the Pennington Street Garage 60 kW DC capacity solar unit installed in downtown Tucson will be applied to the model for testing and verification of the evaluation method. Data was provided by other utilities, but critical time periods of data were missing making results derived from that data inaccurate. The algorithms are based on previous analysis and review of specific 2005 and 2006 SGSSS production data. The model was built, tested and verified by in house TEP personnel. For this phase of the project, TEP communicated with, shared solar production data with and collaborated on the development of solar generation valuation tools with other utilities, including Arizona Public

  19. New Materials for High Temperature Thermoelectric Power Generation

    SciTech Connect

    Kauzlarich, Susan

    2016-02-03

    The scope of this proposal was to develop two new high ZT materials with enhanced properties for the n- and p-leg of a thermoelectric device capable of operating at a maximum temperature of 1275 K and to demonstrate the efficiency in a working device. Nanostructured composites and new materials based on n– and p–type nanostructured Si1-xGex (ZT1273K ~ 1) and the recently discovered p–type high temperature Zintl phase material, Yb14MnSb11 (ZT1273K ~1) were developed and tested in a working device.

  20. 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.

  1. 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.

  2. 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.

  3. [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.

  4. 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.

  5. 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

  6. 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.

  7. Enhanced Flexible Thermoelectric Generators Based on Oxide-Metal Composite Materials

    NASA Astrophysics Data System (ADS)

    Geppert, Benjamin; Brittner, Artur; Helmich, Lailah; Bittner, Michael; Feldhoff, Armin

    2017-04-01

    The thermoelectric performance of flexible thermoelectric generator stripes was investigated in terms of different material combinations. The thermoelectric generators were constructed using Cu-Ni-Mn alloy as n-type legs while varying the p-type leg material by including a metallic silver phase and an oxidic copper phase. For the synthesis of Ca_3Co_4O9/CuO/Ag ceramic-based composite materials, silver and the copper were added to the sol-gel batches in the form of nitrates. For both additional elements, the isothermal specific electronic conductivity increases with increasing amounts of Ag and CuO in the samples. The amounts for Ag and Cu were 0 mol.%, 2 mol.%, 5 mol.%, 10 mol.%, and 20 mol.%. The phases were confirmed by x-ray diffraction. Furthermore, secondary electron microscopy including energy dispersive x-ray spectroscopy were processed in the scanning electron microscope and the transmission electron microscope. For each p-type material, the data for the thermoelectric parameters, isothermal specific electronic conductivity σ and the Seebeck coefficient α, were determined. The p-type material with a content of 5 mol.% Ag and Cu exhibited a local maximum of the power factor and led to the generator with the highest electric power output P_el.

  8. 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.

  9. Solar thermal power generation. A bibliography with abstracts

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Bibliographies and abstracts are cited under the following topics: (1) energy overviews; (2) solar overviews; (3) conservation; (4) economics, law; (5) thermal power; (6) thermionic, thermoelectric; (7) ocean; (8) wind power; (9) biomass and photochemical; and (10) large photovoltaics.

  10. 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

  11. Simple Experiments on the Use of Solar Energy

    ERIC Educational Resources Information Center

    Vella, G. J.; Goldsmid, H. J.

    1976-01-01

    Describes 5 solar energy experiments that can be used in secondary school: flat-plate collector, solar thermoelectric generator, simple concentrators, solar cell, and natural storage of solar energy. (MLH)

  12. 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.

  13. 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.

  14. Performance Study of Thermoelectric Solar-Assisted Heat Pump with Reflectors

    NASA Astrophysics Data System (ADS)

    Lertsatitthanakorn, C.; Soponronnarit, S.; Jamradloedluk, J.; Rungsiyopas, M.; Sarachitti, R.

    2014-06-01

    The simultaneous conversion of solar radiation into thermal and electrical energy in a thermoelectric (TE) solar-assisted heat pump is, for the purposes of this study, referred to as hybrid conversion. To capture more thermal and electrical energy, flat-plate reflectors have been mounted on a TE solar collector. To obtain higher solar radiation intensity on the TE solar collector, the position of the reflectors has been changed and the optimal position of the reflectors determined by both experimental measurements and numerical calculation so as to obtain maximal concentration of solar radiation intensity. The calculated values have been found to be in good agreement with measured ones. Improvements to the thermal energy and electrical power outputs of the system can be achieved by the use of the TE solar-assisted heat pump with reflectors. For the optimum position of the reflectors, the coefficient of performance (COP) of the system formed from a TE solar collector integrated with a heat pump (TESC-HP) was 5.60. The power output and conversion efficiency of the TE modules can reach 10.09 W and 2.40%, respectively, being improved by 34.5% and 18.2%, respectively, compared with the TESC-HP without reflectors.

  15. RAPID COMMUNICATION: Novel high performance small-scale thermoelectric power generation employing regenerative combustion systems

    NASA Astrophysics Data System (ADS)

    Weinberg, F. J.; Rowe, D. M.; Min, G.

    2002-07-01

    Hydrocarbon fuels have specific energy contents some two orders of magnitude greater than any electrical storage device. They therefore proffer an ideal source in the universal quest for compact, lightweight, long-lasting alternatives for batteries to power the ever-proliferating electronic devices. The motivation lies in the need to power, for example, equipment for infantry troops, for weather stations and buoys in polar regions which need to signal their readings intermittently to passing satellites, unattended over long periods, and many others. Fuel cells, converters based on miniaturized gas turbines, and other systems under intensive study, give rise to diverse practical difficulties. Thermoelectric devices are robust, durable and have no moving parts, but tend to be exceedingly inefficient. We propose regenerative combustion systems which mitigate this impediment and are likely to make high performance small-scale thermoelectric power generation applicable in practice. The efficiency of a thermoelectric generating system using preheat when operated between ambient and 1200 K is calculated to exceed the efficiency of the best present day thermoelectric conversion system by more than 20%.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    Zhang, Zheng; Zheng, Ding; Chen, Yushan

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

  18. Micro-Thermoelectric Generation Modules Fabricated with Low-Cost Mechanical Machining Processes

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    Micro/small-scale thermoelectric generation modules are able to produce continuous, noise-free and reliable electricity power using low temperature differences that widely exist in nature or industry. These advantages bring them great application prospects in the fields of remote monitoring, microelectronics/micro-electromechanical systems (MEMS), medical apparatus and smart management system, which often require a power source free of maintenance and vibration. In this work, a prototypical thermoelectric module (12 mm × 12 mm × 0.8 mm) with 15 pairs of micro-scale thermoelectric legs (0.2 mm in width and 0.6 mm in height for each leg) is fabricated using a low-cost mechanical machining process. In this process, cutting and polishing are the main methods for the preparation of thermoelectric pairs from commercial polycrystalline materials and for the fabrication of electrode patterns. The as-fabricated module is tested for its power generation properties with the hot side heated by an electrical heater and the cold side by cold air. With the heater temperature of 375 K, the thermoelectric potential is about 9.1 mV, the short circuit current is about 14.5 mA, and the maximum output power is about 32.8 μW. The finite element method is applied to analyze the heat transfer of the module during our test. The temperature difference and heat flux are simulated, according to which the output powers at different temperatures are calculated, and the result is relatively consistent compared to the test results.

  19. 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.

  20. Complex oxides useful for thermoelectric energy conversion

    DOEpatents

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

    2012-07-17

    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.

  1. 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

  2. Thermoelectric Materials at 300k.

    DTIC Science & Technology

    Thermoelectric power generation, *Peltier effect, *Semiconductors, Thermoelectricity, Seebeck effect , Tellurides, Selenides, Antimonides, Thermal conductivity, Air conditioning equipment, Bismuth compounds, Band theory of solids

  3. Integration of Research for an Exhaust Thermoelectric Generator and the Outer Flow Field of a Car

    NASA Astrophysics Data System (ADS)

    Jiang, T.; Su, C. Q.; Deng, Y. D.; Wang, Y. P.

    2016-11-01

    The exhaust thermoelectric generator (TEG) can generate electric power from a car engine's waste heat. It is important to maintain a sufficient temperature difference across the thermoelectric modules. The radiator is connected to the cooling units of the thermoelectric modules and used to take away the heat from the TEG system. This paper focuses on the research for the integration of a TEG radiator and the flow field of the car chassis, aiming to cool the radiator by the high speed flow around the chassis. What is more, the TEG radiator is designed as a spoiler to optimize the flow field around the car chassis and even reduce the aerodynamic drag. Concentrating on the flow pressure of the radiator and the aerodynamic drag force, a sedan model with eight different schemes of radiator configurations are studied by computational fluid dynamics simulation. Finally, the simulation results indicate that a reasonable radiator configuration can not only generate high flow pressure to improve the cooling performance, which provides a better support for the TEG system, but also acts as a spoiler to reduce the aerodynamic drag force.

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  5. 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.

  6. Solar driven liquid metal MHD power generator

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Hohl, F. (Inventor)

    1983-01-01

    A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled.

  7. Marine Thermoelectric Devices and Installations,

    DTIC Science & Technology

    thermoelectric devices and units as marine sources of electric power, Prospects for the use of thermoelectric generators in main ship propulsion plants, Electric propulsion complexes for marine thermoelectric plants).

  8. Flexible screen printed thick film thermoelectric generator with reduced material resistivity

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    This work presents a flexible thick-film Bismuth Tellurium/Antimony Tellurium (BiTe/SbTe) thermoelectric generator (TEG) with reduced material resistivity fabricated by screen printing technology. Cold isostatic pressing (CIP) was introduced to lower the resistivity of the printed thermoelectric materials. The Seebeck coefficient (α) and the resistivity (ρ) of printed materials were measured as a function of applied pressure. A prototype TEG with 8 thermocouples was fabricated on flexible polyimide substrate. The dimension of a single printed element was 20 mm × 2 mm × 78.4 pm. The coiled-up prototype produced a voltage of 36.4 mV and a maximum power of 40.3 nW from a temperature gradient of 20 °C.

  9. Annular screen printed thermoelectric generators for ultra-low-power sensor applications

    NASA Astrophysics Data System (ADS)

    Gima, Z. T.; Gururangan, K.; Evans, J.; Wright, P.

    2016-11-01

    We report on the materials preparation and device fabrication for screen printed Bi2Te3/Bi0.5Sb1.5Te3 annular thermoelectric generators (TEGs) for use in ultra-low-power sensor applications. At a 20K temperature gradient, test couples — n- & p-type 1 cm2 squares connected electrically in series with printed Ag traces — demonstrated an average power of 0.068nW at 26nA and 2.6mV. The material preparation leverages mechanical alloying for both the n- and p-type materials in order to reduce electrical resistivity and increase device power output. Screen printed thermoelectric elements were found to have substantial challenges with mechanical failure due to cracking and delamination. This work specifically describes these challenges and corresponding mitigation strategies for screen printing the TEG slurries.

  10. 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.

  11. Geometry Optimization of a Segmented Thermoelectric Generator Based on Multi-parameter and Nonlinear Optimization Method

    NASA Astrophysics Data System (ADS)

    Cai, Lanlan; Li, Peng; Luo, Qi; Zhai, Pengcheng; Zhang, Qingjie

    2017-01-01

    As no single thermoelectric material has presented a high figure-of-merit (ZT) over a very wide temperature range, segmented thermoelectric generators (STEGs), where the p- and n-legs are formed of different thermoelectric material segments joined in series, have been developed to improve the performance of thermoelectric generators. A crucial but difficult problem in a STEG design is to determine the optimal values of the geometrical parameters, like the relative lengths of each segment and the cross-sectional area ratio of the n- and p-legs. Herein, a multi-parameter and nonlinear optimization method, based on the Improved Powell Algorithm in conjunction with the discrete numerical model, was implemented to solve the STEG's geometrical optimization problem. The multi-parameter optimal results were validated by comparison with the optimal outcomes obtained from the single-parameter optimization method. Finally, the effect of the hot- and cold-junction temperatures on the geometry optimization was investigated. Results show that the optimal geometry parameters for maximizing the specific output power of a STEG are different from those for maximizing the conversion efficiency. Data also suggest that the optimal geometry parameters and the interfacial temperatures of the adjacent segments optimized for maximum specific output power or conversion efficiency vary with changing hot- and cold-junction temperatures. Through the geometry optimization, the CoSb3/Bi2Te3-based STEG can obtain a maximum specific output power up to 1725.3 W/kg and a maximum efficiency of 13.4% when operating at a hot-junction temperature of 823 K and a cold-junction temperature of 298 K.

  12. Geometry Optimization of a Segmented Thermoelectric Generator Based on Multi-parameter and Nonlinear Optimization Method

    NASA Astrophysics Data System (ADS)

    Cai, Lanlan; Li, Peng; Luo, Qi; Zhai, Pengcheng; Zhang, Qingjie

    2017-03-01

    As no single thermoelectric material has presented a high figure-of-merit (ZT) over a very wide temperature range, segmented thermoelectric generators (STEGs), where the p- and n-legs are formed of different thermoelectric material segments joined in series, have been developed to improve the performance of thermoelectric generators. A crucial but difficult problem in a STEG design is to determine the optimal values of the geometrical parameters, like the relative lengths of each segment and the cross-sectional area ratio of the n- and p-legs. Herein, a multi-parameter and nonlinear optimization method, based on the Improved Powell Algorithm in conjunction with the discrete numerical model, was implemented to solve the STEG's geometrical optimization problem. The multi-parameter optimal results were validated by comparison with the optimal outcomes obtained from the single-parameter optimization method. Finally, the effect of the hot- and cold-junction temperatures on the geometry optimization was investigated. Results show that the optimal geometry parameters for maximizing the specific output power of a STEG are different from those for maximizing the conversion efficiency. Data also suggest that the optimal geometry parameters and the interfacial temperatures of the adjacent segments optimized for maximum specific output power or conversion efficiency vary with changing hot- and cold-junction temperatures. Through the geometry optimization, the CoSb3/Bi2Te3-based STEG can obtain a maximum specific output power up to 1725.3 W/kg and a maximum efficiency of 13.4% when operating at a hot-junction temperature of 823 K and a cold-junction temperature of 298 K.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  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. 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.

  19. Solar-driven liquid metal magnetohydrodynamic generator

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Hohl, F.

    1981-01-01

    A solar oven heated by concentrated solar radiation as the heat source of a liquid metal magnetohydrodynamic (LMMHD) power generation system is proposed. The design allows the production of electric power in space, as well as on Earth, at high rates of efficiency. Two types of the solar oven suitable for the system are discussed.

  20. Fuel Economy Improvement by Utilizing Thermoelectric Generator in Heavy-Duty Vehicle

    NASA Astrophysics Data System (ADS)

    Deng, Y. D.; Hu, T.; Su, C. Q.; Yuan, X. H.

    2016-10-01

    Recent advances in thermoelectric technology have made exhaust-based thermoelectric generators (TEGs) promising for recovery of waste heat. Utilization of exhaust-based TEGs in heavy-duty vehicles was studied in this work. Given that the generated power is limited, the alternator is still indispensable. To improve the fuel economy, the generated electricity must be integrated into the automotive electrical system and consumed by electrical loads. Therefore, two feasible ways of integrating the generated electricity into the automotive electrical system are discussed: one in which the original alternator works only under certain conditions, i.e., the "thermostat" strategy, and another in which a smaller alternator is adopted and works together with the TEG, i.e., the "cooperative work" strategy. The overall performance and efficiency are obtained through simulation analysis. The simulation results show that both methods can improve the fuel economy, but the former provides better results. Moreover, if the electrical loads can be properly modified, the fuel economy is further improved. These simulation results lay a solid foundation for application of TEGs in vehicles in the future.

  1. Polyimide/PDMS flexible thermoelectric generator for ambient assisted living applications

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

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

  2. 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.

  3. Band alignment measurements at heterojunction interfaces in layered thin film solar cells & thermoelectrics

    NASA Astrophysics Data System (ADS)

    Fang, Fang

    2011-12-01

    Public awareness of the increasing energy crisis and the related serious environmental concerns has led to a significantly growing demand for alternative clean and renewable energy resources. Thin film are widely applied in multiple renewable energy devices owing to the reduced amount of raw materials and increase flexibility of choosing from low-cost candidates, which translates directly into reduced capital cost. This is a key driving force to make renewable technology competitive in the energy market. This thesis is focused on the measurement of energy level alignments at interfaces of thin film structures for renewable energy applications. There are two primary foci: II -VI semiconductor ZnSe/ZnTe thin film solar cells and Bi2Te3/Sb2Te3 thin film structures for thermoelectric applications. In both cases, the electronic structure and energy band alignment at interfaces usually controls the carrier transport behavior and determines the quality of the device. High-resolution photoemission spectroscopy (lab-based XPS & synchrotron-based UPS) was used to investigate the chemical and electronic properties of epitaxial Bi2Te3 and Sb2Te3 thin films, in order to validate the anticipated band alignment at interfaces in Bi 2Te3/Sb2Te3 superlattices as one favoring electron-transmission. A simple, thorough two-step treatment of a chemical etching in dilute hydrochloric acid solution and a subsequent annealing at ˜150°C under ultra-high vacuum environment is established to remove the surface oxides completely. It is an essential step to ensure the measurements on electronic states are acquired on stoichimetric, oxide-free clean surface of Bi 2Te3 and Sb2Te3 films. The direct measurement of valence band offsets (VBO) at a real Sb 2Te3/Bi2Te3 interface is designed based on the Kraut model; a special stacking film structure is prepared intentionally: sufficiently thin Sb2Te3 film on top of Bi2Te 3 that photoelectrons from both of them are collected simultaneously. From a

  4. Eco green flexible hybrid photovoltaic-thermoelectric solar cells with nanoimprint technology and roll-to-roll manufacturing

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Choi, Sang H.

    2010-04-01

    This paper explores the technical and commercial feasibility of nanotechnology based, high-efficiency, photovoltaic-thermoelectric hybrid solar cells as an environmentally-friendly, renewable energy source for residential and commercial buildings. To convert as much as possible of the usable photovoltaic (58% of the Energy Density) and thermoelectric (42% of the Energy Density) solar spectrum into electricity, a hybrid multilayer system is presented which comprises of 1) carbon nanotube (CNT) embedded in conducting polymers such as P3HT (poly(3-hexylthiophene) or P3OT (poly3-octylthiophene), 2) 3D gold nanostructures exhibiting plasmonic resonances for energy conversion, 3) nanoantenna architecture to capture IR energy, 4) a composite of Bi2Te3, SiGe nanocrystals and Au nanoshells as thermoelectric energy conversion layer, 5) configuration of the above items engineered in the form of meta-material designs that by virtue of their 3D structures ensure that incident light is neither reflected nor transmitted, but is rather all absorbed, 6) a multilayer arrangement of the above layers in a fractal architecture to capture all the wavelengths from 200 to 3000 nm8 and the matching electronic interface for each layer. The roll-to-roll manufacturing method presented will enable economical large-scale production of solar panels. This potentially transformational technology has the ability to replace the Si solar cell technology by reducing costs from 0.18/KWh to 0.003/KWh while introducing a more environmentally-friendly manufacturing process.

  5. Radioisotope Thermoelectric Generator Package O-Ring Seal Material Validation Testing

    SciTech Connect

    Adkins, H.E.; Ferrell, P.C.; Knight, R.C.

    1994-09-30

    The Radioisotope Thermoelectric Generator Package O-Ring Seal Material Validation Test was conducted to validate the use of the Butyl material as a primary seal throughout the required temperature range. Three tests were performed at (1) 233 K ({minus}40 {degrees}F), (2) a specified operating temperature, and (3) 244 K ({minus}20 {degrees}F) before returning to room temperature. Helium leak tests were performed at each test point to determine seal performance. The two major test objectives were to establish that butyl rubber material would maintain its integrity under various conditions and within specified parameters and to evaluate changes in material properties.

  6. 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.

  7. 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.

  8. 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)

  9. 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.

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

    SciTech Connect

    Not Available

    1991-01-01

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

  11. 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.

  12. 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

  13. Solar thermoelectric cooling using closed loop heat exchangers with macro channels

    NASA Astrophysics Data System (ADS)

    Atta, Raghied M.

    2017-01-01

    In this paper we describe the design, analysis and experimental study of an advanced coolant air conditioning system which cools or warms airflow using thermoelectric (TE) devices powered by solar cells. Both faces of the TE devices are directly connected to closed-loop highly efficient channels plates with macro scale channels and liquid-to-air heat exchangers. The hot side of the system consists of a pump that moves a coolant through the hot face of the TE modules, a radiator that drives heat away into the air, and a fan that transfer the heat over the radiator by forced convection. The cold side of the system consists also of a pump that moves coolant through the cold face of the TE modules, a radiator that drives cold away into the air, and a fan that blows cold air off the radiator. The system was integrated with solar panels, tested and its thermal performance was assessed. The experimental results verify the possibility of heating or cooling air using TE modules with a relatively high coefficient of performance (COP). The system was able to cool a closed space of 30 m3 by 14 °C below ambient within 90 min. The maximum COP of the whole system was 0.72 when the TE modules were running at 11.2 Å and 12 V. This improvement in the system COP over the air cooled heat sink is due to the improvement of the system heat exchange by means of channels plates.

  14. Performance parameters and numerical model of thermoelectric generator dedicated for energy harvesting from flue gases

    NASA Astrophysics Data System (ADS)

    Borcuch, M.; Musiał, M.; Gumuła, S.; Wojciechowski, K. T.

    2016-09-01

    The paper presents results of preliminary studies of thermoelectric generator (TEG) dedicated for waste heat harvesting from flue gases. Investigation includes numerical analysis for estimating power losses due to pressure drop in the installation with the TEG and experimental tests for obtaining electrical parameters and operation conditions, such as casing temperatures and the temperature difference between the inlet and the outlet. Proposed prototype has been equipped with the pin fins for increase the heat transfer. Results indicates that power losses are negligible in comparison with generated electrical power. The heat exchanger's interior demands to be modified to enhance the efficiency by increasing temperatures on the external surfaces of the hot-side heat exchanger (HHX). Further research will focus on numerical analysis of the influence of geometry modifications on the thermal and flow parameters of the TEG resulting in the increase of generated power and efficiency.

  15. 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

    2016-03-02

    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.

  16. CMOS MEMS-based thermoelectric generator with an efficient heat dissipation path

    NASA Astrophysics Data System (ADS)

    Yu, Xiao; Wang, Yuchen; Liu, Yanxiang; Li, Tie; Zhou, Hong; Gao, Xiuli; Feng, Fei; Roinila, Tomi; Wang, Yuelin

    2012-10-01

    This paper presents a CMOS MEMS-based thermoelectric energy generator (TEG) device with an efficient heat dissipation path. For present CMOS MEMS-based thermoelectric generator devices, the output performance is greatly limited by the high thermal-contact resistance in the system. For the device proposed in the work, the silicon substrate is etched into two comb-shaped blocks thermally isolated from each other, which form the hot and cold sides. Thin-film-based thermal legs are densely located between the two blocks along the winding split line. Low internal thermal-contact resistance is achieved with the symmetrical thermal structure. When the TEG device is embedded between the heat source and heat sink, the heat loss can be well controlled with flat thermal-contact pads of the device. For a full device with 900 n/p-polysilicon thermocouples, the measured open-circuit voltage reaches as high as 146 mV K-1, and the power factor reaches almost five times higher value compared to the previously reported results. A test system integrated with a single device presents an open-circuit voltage of 110 mV K-1 when forcibly cooled by a Peltier cooler, or 26 mV K-1 when cooled by ambient air.

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

    NASA Astrophysics Data System (ADS)

    Nesarajah, Marco; Frey, Georg

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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Investigation of Counter-Flow in a Heat Pipe-Thermoelectric Generator (HPTEG)

    NASA Astrophysics Data System (ADS)

    Remeli, Muhammad Fairuz; Singh, Baljit; Affandi, Nor Dalila Nor; Ding, Lai Chet; Date, Abhijit; Akbarzadeh, Aliakbar

    2016-12-01

    This study explores a method of generating electricity while recovering waste heat through the integration of heat pipes and thermoelectric generators (i.e. HPTEG system). The simultaneous waste heat recovery and power generation processes are achieved without the use of any moving parts. The HPTEG system consists of bismuth telluride thermoelectric generators (TEG), which are sandwiched between two finned pipes to achieve a temperature gradient across the TEG for electricity generation. A counter-flow heat exchanger was built using two separate air ducts. The air ducts were thermally coupled using the HPTEG modules. The evaporator section of the heat pipe absorbed the waste heat in a hot air duct. The heat was then transferred across the TEG surfaces. The condenser section of the HPTEG collected the excess heat from the TEG cold side before releasing it to the cold air duct. A 2-kW electrical heater was installed in the hot air duct to simulate the exhaust gas. An air blower was installed at the inlet of each duct to direct the flow of air into the ducts. A theoretical model was developed for predicting the performance of the HPTEG system using the effectiveness-number of transfer units method. The developed model was able to predict the thermal and electrical output of the HPTEG, along with the rate of heat transfer. The results showed that by increasing the cold air velocity, the effectiveness of the heat exchanger was able to be increased from approximately 52% to 58%. As a consequence of the improved heat transfer, maximum power output of 4.3 W was obtained.

  4. Solar steam generation by heat localization.

    PubMed

    Ghasemi, Hadi; Ni, George; Marconnet, Amy Marie; Loomis, James; Yerci, Selcuk; Miljkovic, Nenad; Chen, Gang

    2014-07-21

    Currently, steam generation using solar energy is based on heating bulk liquid to high temperatures. This approach requires either costly high optical concentrations leading to heat loss by the hot bulk liquid and heated surfaces or vacuum. New solar receiver concepts such as porous volumetric receivers or nanofluids have been proposed to decrease these losses. Here we report development of an approach and corresponding material structure for solar steam generation while maintaining low optical concentration and keeping the bulk liquid at low temperature with no vacuum. We achieve solar thermal efficiency up to 85% at only 10 kW m(-2). This high performance results from four structure characteristics: absorbing in the solar spectrum, thermally insulating, hydrophilic and interconnected pores. The structure concentrates thermal energy and fluid flow where needed for phase change and minimizes dissipated energy. This new structure provides a novel approach to harvesting solar energy for a broad range of phase-change applications.

  5. Solar steam generation by heat localization

    NASA Astrophysics Data System (ADS)

    Ghasemi, Hadi; Ni, George; Marconnet, Amy Marie; Loomis, James; Yerci, Selcuk; Miljkovic, Nenad; Chen, Gang

    2014-07-01

    Currently, steam generation using solar energy is based on heating bulk liquid to high temperatures. This approach requires either costly high optical concentrations leading to heat loss by the hot bulk liquid and heated surfaces or vacuum. New solar receiver concepts such as porous volumetric receivers or nanofluids have been proposed to decrease these losses. Here we report development of an approach and corresponding material structure for solar steam generation while maintaining low optical concentration and keeping the bulk liquid at low temperature with no vacuum. We achieve solar thermal efficiency up to 85% at only 10 kW m-2. This high performance results from four structure characteristics: absorbing in the solar spectrum, thermally insulating, hydrophilic and interconnected pores. The structure concentrates thermal energy and fluid flow where needed for phase change and minimizes dissipated energy. This new structure provides a novel approach to harvesting solar energy for a broad range of phase-change applications.

  6. Combination of PVA with Graphene to Improve the Seebeck Coefficient for Thermoelectric Generator Applications

    NASA Astrophysics Data System (ADS)

    Mahmoud, L.; Abdul Samad, Y.; Alhawari, M.; Mohammad, B.; Liao, K.; Ismail, M.

    2015-01-01

    Ultrasensitive thermoelectric (TE) materials are essential for the next generation of self-powered electronic devices. In this work, a graphene-based TE generator was fabricated. For 50 to 1000 graphene layers the average Seebeck coefficient was 90 μV/K. We also report improvement of the Seebeck coefficient by use of a hybrid material containing 10% poly(vinyl alcohol) (PVA) and 90% graphene oxide prepared and tested under the same conditions. The results show that the Seebeck coefficient is improved by an average of 30% compared with graphene alone. Because the fabrication process is facile, scalable, and cost effective, it could also be applicable to other fields of science and engineering.

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

    SciTech Connect

    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.

  8. 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.

  9. 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.

  10. 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.

  11. A Simulation Study on a Thermoelectric Generator for Waste Heat Recovery from a Marine Engine

    NASA Astrophysics Data System (ADS)

    Ji, Dongxu; Tseng, King Jet; Wei, Zhongbao; Zheng, Yun; Romagnoli, Alessandro

    2016-10-01

    In this study, a marine engine has been evaluated for waste heat recovery (WHR) using thermoelectric generators (TEG). The feasibility of Mg2Sn0.75Ge0.25, Cu2Se, and Cu1.98Se as potential thermoelectric (TE) material were investigated. A straight fin heat exchanger is used to enhance the heat transfer between the hot exhaust gas and TE modules. To facility the analysis, a system level thermal resistance model is built and validated with experiments. After the model is validated, a small marine engine with rated power of 1.7-3 MW is taken as baseline model and it is found that around 2-4 KW electrical power can be extracted from exhaust gas by the TEG at varying design and operating parameters. The back pressure effect induced by the heat exchanger is also considered in this study. Finally, a parameter study is conducted regarding the impact of the TE module height on the output power. It is shown that the height of the TE leg could play a significant role in the module geometry design, and that the optimal height varies between 1 mm and 2 mm under different heat exchangers and exhaust gas flow rates.

  12. 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.

  13. 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.

  14. In-situ nanostructure generation and evolution within a bulk thermoelectric material to reduce lattice thermal conductivity

    SciTech Connect

    Girard, Steven; He, Jiaqing; Li, Chang-Peng; Moses, Steven; Wang, Guoyu Y.; Uher, Ctirad; Dravid, Vinayak; Kanatzidis, Mercouri G.

    2010-07-26

    We show experimentally the direct reduction in lattice thermal conductivity as a result of in situ nanostructure generation within a thermoelectric material. Solid solution alloys of the high-performance thermoelectric PbTe-PbS 8% can be synthesized through rapid cooling and subsequent high-temperature activation that induces a spontaneous nucleation and growth of PbS nanocrystals. The emergence of coherent PbS nanostructures reduces the lattice thermal conductivity from ~1 to ~0.4 W/mK between 400 and 500 K.

  15. Increasing the Efficiency of a Thermoelectric Generator Using an Evaporative Cooling System

    NASA Astrophysics Data System (ADS)

    Boonyasri, M.; Jamradloedluk, J.; Lertsatitthanakorn, C.; Therdyothin, A.; Soponronnarit, S.

    2016-11-01

    A system for reducing heat from the cold side of a thermoelectric (TE) power generator, based on the principle of evaporative cooling, is presented. An evaporative cooling system could increase the conversion efficiency of a TE generator. To this end, two sets of TE generators were constructed. Both TE generators were composed of five TE power modules. The cold and hot sides of the TE modules were fixed to rectangular fin heat sinks. The hot side heat sinks were inserted in a hot gas duct. The cold side of one set was cooled by the cooling air from a counter flow evaporative cooling system, whereas the other set was cooled by the parallel flow evaporative cooling system. The counter flow pattern had better performance than the parallel flow pattern. A comparison between the TE generator with and without an evaporative cooling system was made. Experimental results show that the power output increased by using the evaporative cooling system. This can significantly increase the TE conversion efficiency. The evaporative cooling system increased the power output of the TE generator from 22.9 W of ambient air flowing through the heat sinks to 28.6 W at the hot gas temperature of 350°C (an increase of about 24.8%). The present study shows the promising potential of using TE generators with evaporative cooling for waste heat recovery.

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

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

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

  17. 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.

  18. Synthetic thermoelectric materials comprising phononic crystals

    DOEpatents

    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.

  19. Solar generation of the fullerenes

    SciTech Connect

    Chibante, L.P.F.; Thess, A.; Alford, J.M.; Diener, M.D.; Smalley, R.E. )

    1993-08-26

    Fullerenes have been produced efficiently by direct vaporization of carbon in focused sunlight. Large-scale solar furnace implementations of this simple process may be uniquely capable of producing fullerenes and doped fullerenes in large amounts while avoiding the yield-limiting problems encountered with carbon arcs or plasmas. Evidence is presented that the worst of these problems is photochemical destruction of the fullerenes in the light from the arc. Solar furnaces can mitigate this problem both by avoiding the intense ultraviolet radiation associated with arcs and by preventing clustering of the carbon vapor until it passes into a relatively dark cluster formation and annealing zone. 21 refs., 4 figs.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Machine-Thermal Coupling Stresses Analysis of the Fin-Type Structural Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Zhang, Zheng; Yue, Hao; Chen, Dongbo; Qin, Delei; Chen, Zijian

    2017-02-01

    The design structure and heat-transfer mechanism of a thermoelectric generator (TEG) determine its body temperature state. Thermal stress and thermal deformation generated by the temperature variation directly affect the stress state of thermoelectric modules (TEMs). Therefore, the rated temperature and pressing force of TEMs are important parameters in TEG design. Here, the relationships between structural of a fin-type TEG (FTEG) and these parameters are studied by modeling and "machine-thermal" coupling simulation. An indirect calculation method is adopted in the coupling simulation. First, numerical heat transfer calculations of a three-dimensional FTEG model are conducted according to an orthogonal simulation table. The influences of structural parameters for heat transfer in the channel and outer fin temperature distribution are analyzed. The optimal structural parameters are obtained and used to simulate temperature field of the outer fins. Second, taking the thermal calculation results as the initial condition, the thermal-solid coupling calculation is adopted. The thermal stresses of outer fin, mechanical force of spring-angle pressing mechanism, and clamping force on a TEM are analyzed. The simulation results show that the heat transfer area of the inner fin and the physical parameters of the metal materials are the keys to determining the FTEG temperature field. The pressing mechanism's mechanical force can be reduced by reducing the outer fin angle. In addition, a corrugated cooling water pipe, which has cooling and spring functionality, is conducive to establishing an adaptable clamping force to avoid the TEMs being crushed by the thermal stresses in the body.

  10. 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}.

  11. 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

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

    NASA Astrophysics Data System (ADS)

    McCarty, R.

    2013-07-01

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

  13. A Hybrid Maximum Power Point Tracking Method for Automobile Exhaust Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Quan, Rui; Zhou, Wei; Yang, Guangyou; Quan, Shuhai

    2016-08-01

    To make full use of the maximum output power of automobile exhaust thermoelectric generator (AETEG) based on Bi2Te3 thermoelectric modules (TEMs), taking into account the advantages and disadvantages of existing maximum power point tracking methods, and according to the output characteristics of TEMs, a hybrid maximum power point tracking method combining perturb and observe (P&O) algorithm, quadratic interpolation and constant voltage tracking method was put forward in this paper. Firstly, it searched the maximum power point with P&O algorithms and a quadratic interpolation method, then, it forced the AETEG to work at its maximum power point with constant voltage tracking. A synchronous buck converter and controller were implemented in the electric bus of the AETEG applied in a military sports utility vehicle, and the whole system was modeled and simulated with a MATLAB/Simulink environment. Simulation results demonstrate that the maximum output power of the AETEG based on the proposed hybrid method is increased by about 3.0% and 3.7% compared with that using only the P&O algorithm and the quadratic interpolation method, respectively. The shorter tracking time is only 1.4 s, which is reduced by half compared with that of the P&O algorithm and quadratic interpolation method, respectively. The experimental results demonstrate that the tracked maximum power is approximately equal to the real value using the proposed hybrid method,and it can preferentially deal with the voltage fluctuation of the AETEG with only P&O algorithm, and resolve the issue that its working point can barely be adjusted only with constant voltage tracking when the operation conditions change.

  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

    2016-08-01

    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.

  15. Analysis of Thermal Power Generation Capacity for a Skutterudite-Based Thermoelectric Functional Structure

    NASA Astrophysics Data System (ADS)

    Sun, Yajing; Chen, Gang; Bai, Guanghui; Yang, Xuqiu; Li, Peng; Zhai, Pengcheng

    2016-10-01

    Due to military or other requirements for hypersonic aircraft, the energy supply devices with the advantages of small size and light weight are urgently needed. Compared with the traditional energy supply method, the skutterudite-based thermoelectric (TE) functional structure is expected to generate electrical energy with a smaller structural space in the hypersonic aircraft. This paper mainly focuses on the responded thermal and electrical characteristics of the skutterudite-based TE functional structure (TEFS) under strong heat flux loads. We conduct TE simulations on the transient model of the TEFS with consideration of the heat flux loads and thermal radiation in the hot end and the cooling effect of the phase change material (PCM) in the cold end. We investigate several influential factors on the power generation capacity, such as the phase transition temperature of the PCM, the heat flux loads, the thickness of the TE materials and the thermal conductivity of the frame materials. The results show that better power generation capacity can be achieved with thicker TE materials, lower phase transition temperature and suitable thermal conductivity of the frame materials.

  16. 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.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    Stranz, Andrej; Waag, Andreas; Peiner, Erwin

    2013-07-01

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

  19. 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.

  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. 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.

  2. 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.

  3. Thermoelectric Nanowire Arrays Response to Illumination

    NASA Astrophysics Data System (ADS)

    Huber, Tito; Scott, Reum; Johnson, Scott; Brower, Tina; Nikolaeva, Albina; Konopko, Leonid

    Bismuth nanowire arrays configured on devices where they are capped with a transparent indium tin oxide electrode generate electric power when exposed to light. The arrays feature poor optical reflectivity and, possibly, light trapping. We show experimental results that indicate that the arrays respond to illumination owing to the thermoelectric conversion of heat absorbed at the surface. The unique features of the energy pathway are manifested through a strong temporal and photon wavelength dependence of the photoresponse. Energy conversion in thermoelectrics with light trapping surfaces is a path to fast infrared light detection and across-the-spectrum solar energy harvesting.

  4. Fully Electrical Modeling of Thermoelectric Generators with Contact Thermal Resistance Under Different Operating Conditions

    NASA Astrophysics Data System (ADS)

    Siouane, Saima; Jovanović, Slaviša; Poure, Philippe

    2017-01-01

    The Seebeck effect is used in thermoelectric generators (TEGs) to supply electronic circuits by converting the waste thermal into electrical energy. This generated electrical power is directly proportional to the temperature difference between the TEG module's hot and cold sides. Depending on the applications, TEGs can be used either under constant temperature gradient between heat reservoirs or constant heat flow conditions. Moreover, the generated electrical power of a TEG depends not only on these operating conditions, but also on the contact thermal resistance. The influence of the contact thermal resistance on the generated electrical power have already been extensively reported in the literature. However, as reported in Park et al. (Energy Convers Manag 86:233, 2014) and Montecucco and Knox (IEEE Trans Power Electron 30:828, 2015), while designing TEG-powered circuit and systems, a TEG module is mostly modeled with a Thévenin equivalent circuit whose resistance is constant and voltage proportional to the temperature gradient applied to the TEG's terminals. This widely used simplified electrical TEG model is inaccurate and not suitable under constant heat flow conditions or when the contact thermal resistance is considered. Moreover, it does not provide realistic behaviour corresponding to the physical phenomena taking place in a TEG. Therefore, from the circuit designer's point of view, faithful and fully electrical TEG models under different operating conditions are needed. Such models are mainly necessary to design and evaluate the power conditioning electronic stages and the maximum power point tracking algorithms of a TEG power supply. In this study, these fully electrical models with the contact thermal resistance taken into account are presented and the analytical expressions of the Thévenin equivalent circuit parameters are provided.

  5. 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

  6. Potential Application of a Thermoelectric Generator in Passive Cooling System of Nuclear Power Plants

    NASA Astrophysics Data System (ADS)

    Wang, Dongqing; Liu, Yu; Jiang, Jin; Pang, Wei; Lau, Woon Ming; Mei, Jun

    2016-12-01

    In the design of nuclear power plants, various natural circulation passive cooling systems are considered to remove residual heat from the reactor core in the event of a power loss and maintain the plant's safety. These passive systems rely on gravity differences of fluids, resulting from density differentials, rather than using an external power-driven system. Unfortunately, a major drawback of such systems is their weak driving force, which can negatively impact safety. In such systems, there is a temperature difference between the heat source and the heat sink, which potentially offers a natural platform for thermoelectric generator (TEG) applications. While a previous study designed and analyzed a TEG-based passive core cooling system, this paper considers TEG applications in other passive cooling systems of nuclear power plants, after which the concept of a TEG-based passive cooling system is proposed. In such a system, electricity is produced using the system's temperature differences through the TEG, and this electricity is used to further enhance the cooling process.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Multi-parameter Optimization of a Thermoelectric Power Generator and Its Working Conditions

    NASA Astrophysics Data System (ADS)

    Zhang, T.

    2017-01-01

    The global optimal working conditions and optimal couple design for thermoelectric (TE) generators with realistic thermal coupling between the heat reservoirs and the TE couple were studied in the current work. The heat fluxes enforced by the heat reservoirs at the hot and the cold junctions of the TE couple were used in combination with parameter normalization to obtain a single cubic algebraic equation relating the temperature differences between the TE couple junctions and between the heat reservoirs, through the electric load resistance ratio, the reservoir thermal conductance ratio, the reservoir thermal conductance to the TE couple thermal conductance ratio, the Thomson to Seebeck coefficient ratio, and the figure of merit ( Z) of the material based on the linear TE transport equations and their solutions. A broad reservoir thermal conductance ranging between 0.01 W/K and 100 W/K and TE element length ranging from 10-7 m to 10-3 m were explored to find the global optimal systems. The global optimal parameters related to the working conditions, i.e., reservoir thermal conductance ratio and electric load resistance ratio, and the optimal design parameter related to the TE couple were determined for a given TE material. These results demonstrated that the internal and external electric resistance, the thermal resistance between the reservoirs, the thermal resistance between the reservoir and the TE couple, and the optimal thermoelement length have to be well coordinated to obtain optimal power production.

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

    NASA Astrophysics Data System (ADS)

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

    1990-04-01

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

  14. 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.

  15. 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.

  16. Flexible thermoelectric generator with efficient vertical to lateral heat path films

    NASA Astrophysics Data System (ADS)

    Nishino, T.; Suzuki, T.

    2017-03-01

    This paper presents a flexible thermoelectric generator (TEG) with heat path films, which efficiently convert vertical temperature difference (ΔT) into lateral ΔT for thermocouple (TC). The heat path film consists of copper-filled-vias with low thermal resistance and polymer films with high thermal resistance. They were made in two fabrication steps. The first used a flexible printed circuit board with high density copper-filled-vias, while the second saw the deposition of thin film TCs. The combination offers flexibility of application due to its thinness, mass production potential, and low energy heat loss in the device. We demonstrated 54 TCs cm‑2 in a 25 cm2 flexible TEG using Bi2Te3- and Nickel-based TCs respectively. The experimental data were in good accordance with a model which was calculated using the finite element method. The prototype flexible TEGs indicated that the proposed structure converted 84% heat flow from vertical into lateral ΔT in each TC, which was two times higher than the non-heat path film. They produced voltage of 11 mV/K/cm2 and power output of 0.1 µW/K/cm2 respectively. These flexible TEGs are ideally suited for harvesting from waste heat emitted from objects with large wavy areas because of their low weight, low cost and high efficiency conversion with flexibility.

  17. 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.

  18. 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

  19. 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.

  20. 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.

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

    PubMed

    Li, Sheng; Yao, Xinhua; Fu, Jianzhong

    2014-07-16

    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.

  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. 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.

  5. 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.

  6. 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.

  7. Monolithically self-assembled organic active materials integrated with thermoelectric for large spectrum solar harvesting system (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Busani, Tito L.; Lavrova, Olga; Erdman, Matthew; Martinez, Julio; Dawson, Noel M.

    2015-10-01

    We designed and studied a radial junction composed by a photovoltaic and thermoelectric array based on ZnO and CdTe nanowires surrounded by an absorbing organic self assembled in order to efficiently convert UV-visible and IR energy into electricity. The hot anode of n-type ZnO nanowires was fabricated using a thermal process on pre-seeded layer and results to be crystalline with a transmittance up to 92 % and a bandgap of ~ 3.32 eV. Conductivity measurements reveal diode-like behavior for the ZnO nanowires. The organic layer was deposited between the anode and cathode at room temperature The organic layer is composed of oppositely charged porphyrin metal (Zn(II) and Sn(IV)(OH)2) derivatives that are separately water soluble, but when combined form a virtually insoluble solid. The electron donor/acceptor properties (energy levels, band gaps) of the solid can be controlled by the choice of metals and the nature of the peripheral substituent groups of the porphyrin ring. A defect free sub nanometer deposition was achieved using a layer-by-layer deposition onto both ZnO and Bi2Te3 nanowires. The highly thermoelectric structure, which acts as a cold cathode, is composed of p-type Bi2Te3 nanowires with a thermoelectric efficiency (ZT) between ~0.7 to 1, values that are twice that expected for bulk Bi2Te3. Optoelectronic and structural properties shows that with 6 nm of organic layer it is possible to form a 3% efficient solar device with an enhanced thermo electric effected with a temperature gradient of 300 C.

  8. A New Generation of Standard Solar Models

    NASA Astrophysics Data System (ADS)

    Vinyoles, Núria; Serenelli, Aldo M.; Villante, Francesco L.; Basu, Sarbani; Bergström, Johannes; Gonzalez-Garcia, M. C.; Maltoni, Michele; Peña-Garay, Carlos; Song, Ningqiang

    2017-02-01

    We compute a new generation of standard solar models (SSMs) that includes recent updates on some important nuclear reaction rates and a more consistent treatment of the equation of state. Models also include a novel and flexible treatment of opacity uncertainties based on opacity kernels, required in light of recent theoretical and experimental works on radiative opacity. Two large sets of SSMs, each based on a different canonical set of solar abundances with high and low metallicity (Z), are computed to determine model uncertainties and correlations among different observables. We present detailed comparisons of high- and low-Z models against different ensembles of solar observables, including solar neutrinos, surface helium abundance, depth of the convective envelope, and sound speed profile. A global comparison, including all observables, yields a p-value of 2.7σ for the high-Z model and 4.7σ for the low-Z one. When the sound speed differences in the narrow region of 0.65< r/{R}ȯ < 0.70 are excluded from the analysis, results are 0.9σ and 3.0σ for high- and low-Z models respectively. These results show that high-Z models agree well with solar data but have a systematic problem right below the bottom of the convective envelope linked to steepness of molecular weight and temperature gradients, and that low-Z models lead to a much more general disagreement with solar data. We also show that, while simple parametrizations of opacity uncertainties can strongly alleviate the solar abundance problem, they are insufficient to substantially improve the agreement of SSMs with helioseismic data beyond that obtained for high-Z models due to the intrinsic correlations of theoretical predictions.

  9. Photocurrent generation in nanostructured organic solar cells.

    PubMed

    Yang, Fan; Forrest, Stephen R

    2008-05-01

    Photocurrent generation in nanostructured organic solar cells is simulated using a dynamical Monte Carlo model that includes the generation and transport properties of both excitons and free charges. Incorporating both optical and electrical properties, we study the influence of the heterojunction nanostructure (e.g., planar vs bulk junctions) on donor-acceptor organic solar cell efficiencies based on the archetype materials copper phthalocyanine (CuPc) and C(60). Structures considered are planar and planar-mixed heterojunctions, homogeneous and phase-separated donor-acceptor (DA) mixtures, idealized structures composed of DA pillars, and nanocrystalline DA networks. The thickness dependence of absorption, exciton diffusion, and carrier collection efficiencies is studied for different morphologies, yielding results similar to those experimentally observed. The influences of charge mobility and exciton diffusion length are studied, and optimal device thicknesses are proposed for various structures. Simulations show that, with currently available materials, nanocrystalline network solar cells optimize both exciton diffusion and carrier collection, thus providing for highly efficient solar energy conversion. Estimations of achievable energy conversion efficiencies are made for the various nanostructures based on current simulations used in conjunction with experimentally obtained fill factors and open-circuit voltages for conventional small molecular weight materials combinations.

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  11. Next Generation Solar Collectors for CSP

    SciTech Connect

    Molnar, Attila; Charles, Ruth

    2014-07-31

    The intent of “Next Generation Solar Collectors for CSP” program was to develop key technology elements for collectors in Phase 1 (Budget Period 1), design these elements in Phase 2 (Budget Period 2) and to deploy and test the final collector in Phase 3 (Budget Period 3). 3M and DOE mutually agreed to terminate the program at the end of Budget Period 1, primarily due to timeline issues. However, significant advancements were achieved in developing a next generation reflective material and panel that has the potential to significantly improve the efficiency of CSP systems.

  12. 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.

  13. Photocatalytic Solar Fuel Generation on Semiconductor Nanocrystals

    NASA Astrophysics Data System (ADS)

    Feldmann, Jochen

    2015-03-01

    I will review our scientific work on photocatalytic solar fuel generation utilizing colloidal semiconductor nanocrystals decorated with catalytic metal clusters. In particular, nanocrystals made of CdS, TiO2 and organo-metal halide perovskites will be discussed. Key issues are the role of hole scavangers (M. Berr et al., Appl. Phys. Lett. 100, 223903 (2012)), the size and density of catalytic clusters (M. Berr et al.: Appl. Phys. Lett. 97, 093108 (2010) and Nano Letters 12, 5903 (2012) , and dependencies on external parameters such as pH (T. Simon et al., Nature Mat. 13, 1013 (2014)). Financially supported by the Bavarian Research Cluster ``Solar Technologies Go Hybrid: SolTech''.

  14. 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.

  15. 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)

  16. Dynamic Test Bed Analysis of Gas Energy Balance for a Diesel Exhaust System Fit with a Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Fuc, Pawel; Lijewski, Piotr; Ziolkowski, Andrzej; Dobrzyński, Michal

    2017-02-01

    Analysis of the energy balance for an exhaust system of a diesel engine fit with an automotive thermoelectric generator (ATEG) of our own design has been carried out. A special measurement system and dedicated software were developed to measure the power generated by the modules. The research object was a 1.3-l small diesel engine with power output of 66 kW. The tests were carried out on a dynamic engine test bed that allows reproduction of an actual driving cycle expressed as a function V = f(t), simulating drivetrain (clutch, transmission) operating characteristics, vehicle geometrical parameters, and driver behavior. Measurements of exhaust gas thermodynamic parameters (temperature, pressure, and mass flow) as well as the voltage and current generated by the thermoelectric modules were performed during tests of our own design. Based on the results obtained, the flow of exhaust gas energy in the entire exhaust system was determined along with the ATEG power output. The ideal area of the exhaust system for location of the ATEG was defined to ensure the highest thermal energy recovery efficiency.

  17. 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..

  18. 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.

  19. 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

  20. Enhanced Electron Collection in Perovskite Solar Cells Employing Thermoelectric NaCo2 O4 /TiO2 Coaxial Nanofibers.

    PubMed

    Liu, Tao; Wang, Cheng; Hou, Juan; Zhang, Chuanbo; Chen, Haijun; He, Hongcai; Wang, Ning; Wu, Hui; Cao, Guozhong

    2016-10-01

    Thermoelectric NaCo2 O4 /TiO2 coaxial nanofibers are prepared and distributed in the perovskite solar cells. Under illumination, p-type NaCo2 O4 can convert unwanted heat to thermal voltage, and thus promote the electron extraction and transport with the action of electrostatic force. These advantages collectively contribute to an overall power conversion efficiency improvement of ≈20% (15.14% vs 12.65%).

  1. Implementation of optimum solar electricity generating system

    NASA Astrophysics Data System (ADS)

    Singh, Balbir Singh Mahinder; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep; Karim, Samsul Ariffin A.

    2014-10-01

    Under the 10th Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

  2. Implementation of optimum solar electricity generating system

    SciTech Connect

    Singh, Balbir Singh Mahinder Karim, Samsul Ariffin A.; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep

    2014-10-24

    Under the 10{sup th} Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  4. 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

  5. Goldstone Solar System Radar Waveform Generator

    NASA Technical Reports Server (NTRS)

    Quirk, Kevin J.; Patawaran, Ferze D.; Nguyen, Danh H.; Nguyen, Huy

    2012-01-01

    Due to distances and relative motions among the transmitter, target object, and receiver, the time-base between any transmitted and received signal will undergo distortion. Pre-distortion of the transmitted signal to compensate for this time-base distortion allows reception of an undistorted signal. In most radar applications, an arbitrary waveform generator (AWG) would be used to store the pre-calculated waveform and then play back this waveform during transmission. The Goldstone Solar System Radar (GSSR), however, has transmission durations that exceed the available memory storage of such a device. A waveform generator capable of real-time pre-distortion of a radar waveform to a given time-base distortion function is needed. To pre-distort the transmitted signal, both the baseband radar waveform and the RF carrier must be modified. In the GSSR, this occurs at the up-conversion mixing stage to an intermediate frequency (IF). A programmable oscillator (PO) is used to generate the IF along with a time-varying phase component that matches the time-base distortion of the RF carrier. This serves as the IF input to the waveform generator where it is mixed with a baseband radar waveform whose time-base has been distorted to match the given time-base distortion function producing the modulated IF output. An error control feedback loop is used to precisely control the time-base distortion of the baseband waveform, allowing its real-time generation. The waveform generator produces IF modulated radar waveforms whose time-base has been pre-distorted to match a given arbitrary function. The following waveforms are supported: continuous wave (CW), frequency hopped (FH), binary phase code (BPC), and linear frequency modulation (LFM). The waveform generator takes as input an IF with a time varying phase component that matches the time-base distortion of the carrier. The waveform generator supports interconnection with deep-space network (DSN) timing and frequency standards, and

  6. Elemental Diffusion and Service Performance of Bi2Te3-Based Thermoelectric Generation Modules with Flexible Connection Electrodes

    NASA Astrophysics Data System (ADS)

    Jiang, Chengpeng; Fan, Xi'an; Rong, Zhenzhou; Zhang, Chengcheng; Li, Guangqiang; Feng, Bo; Hu, Jie; Xiang, Qiusheng

    2017-02-01

    In this work, the elemental diffusion and service performance of Bi2Te3-based thermoelectric generation (TEG) modules with flexible Al electrodes were evaluated at a temperature difference of 240°C and a cold junction temperature of 50°C. The results indicated that while the maximum output power ( P max) and open circuit voltage ( U 0) first increased rapidly and then decreased gradually with service time, the dynamic inner-resistance ( R i) showed the opposite trend. Obvious defects and elemental diffusion across the interfaces were observed and resulted in the performance degradation of the TEG modules. The Ni barrier layer with a thickness of 8-10 μm could not effectively restrain the elemental diffusion for the TEG applications at the high operating temperatures. Al was not suitable as the electrode material for the Bi2Te3-based TEG modules due to its ready absorption of Se from the n-type thermoelectric legs. Encouragingly, we found that the Al electrode could restrain the diffusion of the other elements such as Bi, Te, Sb, Cu, Ni, and I. These results provided insight into the improvement of the service performance of the TEG modules.

  7. 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.

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

    SciTech Connect

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

    1987-03-01

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

  9. Generation of solar magnetic fields. I. II

    NASA Astrophysics Data System (ADS)

    Parker, E. N.

    Attention is given to those magnetic field properties which allow the fields to destroy themselves rapidly, thereby producing solar, stellar and geomagnetic activity. Magnetic fields actively figure in the production of flares, plages, eruptions and streamers. The existence of magnetic fields in other stars is inferred from the X-rays that can be observed to radiate from them. In the second part of this paper, the discussion in the first part of the generation of magnetic fields from the motion of conducting fluids is further developed through the proposal of the 'short, sudden' idealization, and quick bursts of turbulence during which any degree of twisting and rotation can be accomplished are introduced. After these quick bursts of motion, the fluid is held motionless so that small scale irregularities subside, leaving a smooth, average and large scale state. This cycle is repeated at time intervals tau, producing the dynamo equations for the mean vector potential.

  10. 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

  11. The F1 Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) : a Power Subsystem Enabler for the Mars Science Laboratory (MSL) Mission

    NASA Technical Reports Server (NTRS)

    Jones, Loren; Moreno, Victor; Zimmerman, Robert

    2013-01-01

    The Mars Science Laboratory (MSL) spacecraft carrying the Curiosity rover launched from Cape Canaveral Air Force Station (CCAFS) on November 26, 2011. Following an 8.5-month cruise and after a successful Entry, Descent and Landing (EDL) phase, the Curiosity rover arrived at the surface of Mars on August 6, 2012 UTC. At the core of the Curiosity rover power subsystem is the F1 Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) supplied by the Department of Energy. Integration of the F1 MMRTG into the MSL spacecraft has provided the first opportunity to architect a power subsystem that also included a Solar Array (during the cruise phase of the mission and up to the initial stage of the EDL phase) and secondary Li-ion batteries for operation during the planned one Martian year surface phase of the mission. This paper describes the F1 MMRTG functional features as an enabler of the MSL mission and as a novel component of the MSL power subsystem architecture.

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  13. Automatic generation and analysis of solar cell IV curves

    DOEpatents

    Kraft, Steven M.; Jones, Jason C.

    2014-06-03

    A photovoltaic system includes multiple strings of solar panels and a device presenting a DC load to the strings of solar panels. Output currents of the strings of solar panels may be sensed and provided to a computer that generates current-voltage (IV) curves of the strings of solar panels. Output voltages of the string of solar panels may be sensed at the string or at the device presenting the DC load. The DC load may be varied. Output currents of the strings of solar panels responsive to the variation of the DC load are sensed to generate IV curves of the strings of solar panels. IV curves may be compared and analyzed to evaluate performance of and detect problems with a string of solar panels.

  14. High Temperature Thermoelectric Materials for Waste Heat Regeneration

    DTIC Science & Technology

    2013-01-01

    producing such technologies as solar (photovoltaic and solar heating ), geothermal , biomass, and wind energy production. Unfortunately, these still...R.; Carr, D.W.G.; Jones, L. Thermoelectrics: From Space Power Systems to Terrestrial Waste Heat Recovery Appications. in 2011 Thermoelectrics...High Temperature Thermoelectric Materials for Waste Heat Regeneration by Horacio Nochetto, Patrick Taylor, and Jay R. Maddux ARL-TR-6311

  15. Solvothermal Synthesis of Tetrahedrite: Speeding Up the Process of Thermoelectric Material Generation.

    PubMed

    James, Derak J; Lu, Xu; Morelli, Donald T; Brock, Stephanie L

    2015-10-28

    Derivatives of synthetic tetrahedrite, Cu12Sb4S13, are receiving increasing attention in the thermoelectric community due to their exploitation of plentiful, relatively nontoxic elements, combined with a thermoelectric performance that rivals that of PbTe-based compounds. However, traditional synthetic methods require weeks of annealing at high temperatures (450-600 °C) and periodic regrinding of the samples. Here we report a solvothermal method to produce tetrahedrite that requires only 1 day of heating at a relatively low temperature (155 °C). This allows preparation of multiple samples at once and is potentially scalable. The solvothermal material described herein demonstrates a dimensionless figure of merit (ZT) vs temperature curve comparable to that of solid-state tetrahedrite, achieving the same ZT of 0.63 at ∼720 K. As with the materials from solid-state synthesis, products from this rapid solvothermal synthesis can be improved by mixing in a 1:1 molar ratio with the Zn-containing natural mineral, tennantite, to achieve 0.9 mol equiv of Zn. This leads to a 36% increase in ZT at ∼720 K for solvothermal tetrahedrite, to 0.85.

  16. 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.

  17. 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.

  18. 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.

  19. Nano-materials Enabled Thermoelectricity from Window Glasses

    PubMed Central

    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 m2 window at a 20°C temperature gradient. If a natural temperature gradient exists, this can serve as a sustainable energy source for green building technology. PMID:23150789

  20. 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.

  1. 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

  2. Thermoelectric-pyroelectric hybrid energy generation from thermopower waves in core-shell structured carbon nanotube-PZT nanocomposites

    NASA Astrophysics Data System (ADS)

    Yeo, Taehan; Hwang, Hayoung; Shin, Dongjoon; Seo, Byungseok; Choi, Wonjoon

    2017-02-01

    There is an urgent need to develop a suitable energy source owing to the rapid development of various innovative devices using micro-nanotechnology. The thermopower wave (TW), which produces a high specific power during the combustion of solid fuel inside micro-nanostructure materials, is a unique energy source for unusual platforms that cannot use conventional energy sources. Here, we report on the significant enhancement of hybrid energy generation of pyroelectrics and thermoelectrics from TWs in carbon nanotube (CNT)-PZT (lead zirconate titanate, P(Z0.5-T0.5)) composites for the first time. Conventional TWs use only charge carrier transport driven by the temperature gradient along the core materials to produce voltage. In this study, a core-shell structure of CNTs-PZTs was prepared to utilize both the temperature gradient along the core material (thermoelectrics) and the dynamic change in the temperature of the shell structure (pyroelectrics) induced by TWs. The dual mechanism of energy generation in CNT-PZT composites amplified the average peak and duration of the voltage up to 403 mV and 612 ms, respectively, by a factor of 2 and 60 times those for the composites without a PZT layer. Furthermore, dynamic voltage measurements and structural analysis in repetitive TWs confirmed that CNT-PZT composites maintain the original performance in multiple TWs, which improves the reusability of materials. The advanced TWs obtained by the application of a PZT layer as a pyroelectric material contributes to the extension of the usable energy portion as well as the development of TW-based operating devices.

  3. Thermoelectric-pyroelectric hybrid energy generation from thermopower waves in core-shell structured carbon nanotube-PZT nanocomposites.

    PubMed

    Yeo, Taehan; Hwang, Hayoung; Shin, Dongjoon; Seo, Byungseok; Choi, Wonjoon

    2017-02-10

    There is an urgent need to develop a suitable energy source owing to the rapid development of various innovative devices using micro-nanotechnology. The thermopower wave (TW), which produces a high specific power during the combustion of solid fuel inside micro-nanostructure materials, is a unique energy source for unusual platforms that cannot use conventional energy sources. Here, we report on the significant enhancement of hybrid energy generation of pyroelectrics and thermoelectrics from TWs in carbon nanotube (CNT)-PZT (lead zirconate titanate, P(Z0.5-T0.5)) composites for the first time. Conventional TWs use only charge carrier transport driven by the temperature gradient along the core materials to produce voltage. In this study, a core-shell structure of CNTs-PZTs was prepared to utilize both the temperature gradient along the core material (thermoelectrics) and the dynamic change in the temperature of the shell structure (pyroelectrics) induced by TWs. The dual mechanism of energy generation in CNT-PZT composites amplified the average peak and duration of the voltage up to 403 mV and 612 ms, respectively, by a factor of 2 and 60 times those for the composites without a PZT layer. Furthermore, dynamic voltage measurements and structural analysis in repetitive TWs confirmed that CNT-PZT composites maintain the original performance in multiple TWs, which improves the reusability of materials. The advanced TWs obtained by the application of a PZT layer as a pyroelectric material contributes to the extension of the usable energy portion as well as the development of TW-based operating devices.

  4. 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.

  5. 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.

  6. Application of field-modulated generator systems to dispersed solar thermal electric generation

    NASA Technical Reports Server (NTRS)

    Ramakumar, R.

    1979-01-01

    The state-of-the-art of field modulated generation system (FMGS) is presented, and the application of FMGS to dispersed solar thermal electric generation is discussed. The control and monitoring requirements for solar generation system are defined. A comparison is presented between the FMGS approach and other options and the technological development needs are discussed.

  7. Concepts for central solar electric power generation

    NASA Technical Reports Server (NTRS)

    Kintigh, J. K.

    1974-01-01

    The investigation reported was conducted to select the best conceptual design of a power plant for the dynamic conversion of solar heat to electricity. Conversion of thermal energy to electricity was to be an accomplished with conventional turbomachinery. Questions of site selection are discussed along with solar energy collection systems, aspects of candidate system definition, and reference systems.

  8. Energetic electrons generated during solar flares

    NASA Astrophysics Data System (ADS)

    Mann, Gottfried

    2015-12-01

    > electrons are accelerated up to energies beyond 30 keV is one of the open questions in solar physics. A flare is considered as the manifestation of magnetic reconnection in the solar corona. Which mechanisms lead to the production of energetic electrons in the magnetic reconnection region is discussed in this paper. Two of them are described in more detail.

  9. Optimization of Heat Exchangers with Dimpled Surfaces to Improve the Performance in Thermoelectric Generators Using a Kriging Model

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    Thermoelectric generators (TEGs) have become a topic of interest for vehicle exhaust energy recovery. Electrical power generation is deeply influenced by temperature differences, temperature uniformity and topological structures of TEGs. When the dimpled surfaces are adopted in heat exchangers, the heat transfer rates can be augmented with a minimal pressure drop. However, the temperature distribution shows a large gradient along the flow direction which has adverse effects on the power generation. In the current study, the heat exchanger performance was studied in a computational fluid dynamics (CFD) model. The dimple depth, dimple print diameter, and channel height were chosen as design variables. The objective function was defined as a combination of average temperature, temperature uniformity and pressure loss. The optimal Latin hypercube method was used to determine the experiment points as a method of design of the experiment in order to analyze the sensitivity of the design variables. A Kriging surrogate model was built and verified according to the database resulting from the CFD simulation. A multi-island genetic algorithm was used to optimize the structure in the heat exchanger based on the surrogate model. The results showed that the average temperature of the heat exchanger was most sensitive to the dimple depth. The pressure loss and temperature uniformity were most sensitive to the parameter of channel rear height, h 2. With an optimal design of channel structure, the temperature uniformity can be greatly improved compared with the initial exchanger, and the additional pressure loss also increased.

  10. Solar-hydrogen generation and solar concentration (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Chinello, Enrico; Modestino, Miguel A.; Schüttauf, Jan-Willem; Lambelet, David; Delfino, Antonio; Dominé, Didier; Faes, Antonin; Despeisse, Matthieu; Bailat, Julien; Psaltis, Demetri; Fernandez Rivas, David; Ballif, Christophe; Moser, Christophe

    2016-09-01

    We successfully demonstrated and reported the highest solar-to-hydrogen efficiency with crystalline silicon cells and Earth-abundant electrocatalysts under unconcentrated solar radiation. The combination of hetero-junction silicon cells and a 3D printed Platinum/Iridium-Oxide electrolyzer has been proven to work continuously for more than 24 hours in neutral environment, with a stable 13.5% solar-to-fuel efficiency. Since the hydrogen economy is expected to expand to a global scale, we demonstrated the same efficiency with an Earth-abundant electrolyzer based on Nickel in a basic medium. In both cases, electrolyzer and photovoltaic cells have been specifically sized for their characteristic curves to intersect at a stable operating point. This is foreseen to guarantee constant operation over the device lifetime without performance degradation. The next step is to lower the production cost of hydrogen by making use of medium range solar concentration. It permits to limit the photoabsorbing area, shown to be the cost-driver component. We have recently modeled a self-tracking solar concentrator, able to capture sunlight within the acceptance angle range +/-45°, implementing 3 custom lenses. The design allows a fully static device, avoiding the external tracker that was necessary in a previously demonstrated +/-16° angular range concentrator. We will show two self-tracking methods. The first one relies on thermal expansion whereas the second method relies on microfluidics.

  11. High voltage solar cell power generating system

    NASA Technical Reports Server (NTRS)

    Levy, E., Jr.; Opjorden, R. W.; Hoffman, A. C.

    1974-01-01

    A laboratory solar power system regulated by on-panel switches has been delivered for operating high power (3 kW), high voltage (15,000 volt) loads (communication tubes, ion thrusters). The modular system consists of 26 solar arrays, each with an integral light source and cooling system. A typical array contains 2,560 series-connected cells. Each light source consists of twenty 500-watt tungsten iodide lamps providing plus or minus 5 percent uniformity at one solar constant. An array temperature of less than 40 C is achieved using an infrared filter, a water-cooled plate, a vacuum hold-down system, and air flushing.

  12. 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.

  13. 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.

  14. 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.

  15. Eastern Renewable Generation Integration Study Solar Dataset (Presentation)

    SciTech Connect

    Hummon, M.

    2014-04-01

    The National Renewable Energy Laboratory produced solar power production data for the Eastern Renewable Generation Integration Study (ERGIS) including "real time" 5-minute interval data, "four hour ahead forecast" 60-minute interval data, and "day-ahead forecast" 60-minute interval data for the year 2006. This presentation provides a brief overview of the three solar power datasets.

  16. 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.

  17. 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.

  18. Design and Performance of 20 Watts Portable Solar Generator

    NASA Astrophysics Data System (ADS)

    Majid, Z. A. Abdul; Hazali, N.; Hanafiah, M. A. K. M.; Abdullah, A. A.; Ismail, A. F.; Ruslan, M. H.; Sopian, K.; Mohd Azmi, M. S.

    2012-09-01

    A new portable solar generator has been developed to generate electricity. It has the potential to replace petrol generator, widely used by peddlers at night markets (pasar malam). Conventional generators are heavy, oily, have high maintenance and use fossil fuel to generate electricity. The solar generator can generate 20 Watts of electricity. This amount of power can supply up to 96 hours of electricity for the purpose of lighting and running small electrical appliances. The power output is (alternating current) AC current using 150 Watts inverter with 200 Watts surge, suitable for all commercial single phase electric appliances. Solar charge controller is used to maximize the charging rate and to protect the battery. The system has low maintenance whereby the batteries need to be changed every three to four years, depending on the usage. The main concepts of portable solar generator are to reduce installation cost and to introduce a compact design of an optimal energy sizing system. The materials used to develop the solar generator can be easily obtained from local markets, thus reducing the cost of developing the system and making it suitable for commercialization.

  19. Solar Power System Design for the Solar Probe+ Mission

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Schmitz, Paul C.; Kinnison, James; Fraeman, Martin; Roufberg, Lew; Vernon, Steve; Wirzburger, Melissa

    2008-01-01

    Solar Probe+ is an ambitious mission proposed to the solar corona, designed to make a perihelion approach of 9 solar radii from the surface of the sun. The high temperature, high solar flux environment makes this mission a significant challenge for power system design. This paper summarizes the power system conceptual design for the solar probe mission. Power supplies considered included nuclear, solar thermoelectric generation, solar dynamic generation using Stirling engines, and solar photovoltaic generation. The solar probe mission ranges from a starting distance from the sun of 1 AU, to a minimum distance of about 9.5 solar radii, or 0.044 AU, from the center of the sun. During the mission, the solar intensity ranges from one to about 510 times AM0. This requires power systems that can operate over nearly three orders of magnitude of incident intensity.

  20. Solar-Driven Liquid-Metal MHD Generator

    NASA Technical Reports Server (NTRS)

    Hohl, F.; Lee, J. H.

    1982-01-01

    Liquid-metal magnetohydrodynamic (MHD) power generator with solar oven as its heat source has potential to produce electric power in space and on Earth at high efficiency. Generator focuses radiation from Sun to heat driving gas that pushes liquid metal past magnetic coil. Power is extracted directly from electric currents set up in conducting liquid. Using solar energy as fuel can save considerable costs and payload weight, compared to previous systems.

  1. 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.

  2. Solar-fuel generation: Towards practical implementation

    NASA Astrophysics Data System (ADS)

    Dahl, Søren; Chorkendorff, Ib

    2012-02-01

    Limiting reliance on non-renewable fossil fuels inevitably depends on a more efficient utilization of solar energy. Materials scientists discuss the most viable approaches to produce high-energy-density fuels from sunlight that can be implemented in existing infrastructures.

  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. 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.

  5. Modelling of segmented high-performance thermoelectric generators with effects of thermal radiation, electrical and thermal contact resistances.

    PubMed

    Ouyang, Zhongliang; Li, Dawen

    2016-04-07

    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.

  6. 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

    2016-12-01

    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.

  7. 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.

  8. 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.

  9. Rankine engine solar power generation. I - Performance and economic analysis

    NASA Technical Reports Server (NTRS)

    Gossler, A. A.; Orrock, J. E.

    1981-01-01

    Results of a computer simulation of the performance of a solar flat plate collector powered electrical generation system are presented. The simulation was configured to include locations in New Mexico, North Dakota, Tennessee, and Massachusetts, and considered a water-based heat-transfer fluid collector system with storage. The collectors also powered a Rankine-cycle boiler filled with a low temperature working fluid. The generator was considered to be run only when excess solar heat and full storage would otherwise require heat purging through the collectors. All power was directed into the utility grid. The solar powered generator unit addition was found to be dependent on site location and collector area, and reduced the effective solar cost with collector areas greater than 400-670 sq m. The sites were economically ranked, best to worst: New Mexico, North Dakota, Massachusetts, and Tennessee.

  10. 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.

  11. 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.

  12. Solar powered pump with electrical generator

    SciTech Connect

    Golben, P.M.

    1989-12-05

    This patent describes a pumping apparatus. It comprises: a solar collector, a heat exchange circuit including a circulating pump for moving a heat exchange fluid between the solar collector and a compressed gas engine for operation thereof, the compressed gas engine provided with a hydriable metal and hydrogen arranged operatively in a sealed loop to drive a master piston, a magnetic coupler for coupling the master piston to a slave well pump piston for conjoined motion therewith, the well pump piston arranged operatively for pumping a liquid, means for passing the liquid in noncontact heat exchange relationship with the hydriable metal for cooling thereof so that it can resorb hydrogen gas, a rack connected to the well pump piston and connected to drive a pinion gear which in turn is connected to run a permanent magnet motor to charge a storage battery which in turn is connected to power the circulating pump.

  13. Generation of solar spectrum by using LEDs

    NASA Astrophysics Data System (ADS)

    Lu, Pengzhi; Yang, Hua; Pei, Yanrong; Li, Jing; Xue, Bin; Wang, Junxi; Li, Jinmin

    2016-09-01

    Light emitting diode (LED) has been recognized as an applicable light source for indoor and outdoor lighting, city beautifying, landscape facilities, and municipal engineering etc. Conventional LED has superior characteristics such as long life time, low power consumption, high contrast, and wide viewing angle. Recently, LED with high color-rendering index and special spectral characteristics has received more and more attention. This paper is intended to report a solar spectrum simulated by multichip LED light source. The typical solar spectrum of 5500k released by CIE was simulated as a reference. Four types of LEDs with different spectral power distributions would be used in the LED light source, which included a 430nm LED, a 480nm LED, a 500nm LED and a white LED. In order to obtain better simulation results, the white LED was achieved by a 450nm LED chip with the mixture of phosphor. The phosphor combination was prepared by mixing green phosphor, yellow phosphor and red phosphor in a certain proportion. The multichip LED light source could provide a high fidelity spectral match with the typical solar spectrum of 5500k by adjusting injection current to each device. The luminous flux, CIE chromaticity coordinate x, y, CCT, and Ra were 104.7 lm, 0.3337, 0.3681, 5460K, and 88.6, respectively. Because of high color-rendering index and highly match to the solar spectrum, the multichip LED light source is a competitive candidate for applications where special spectral is required, such as colorimetric measurements, visual inspection, gemstone identification and agriculture.

  14. Solar Energy Systems for Lunar Oxygen Generation

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Heller, Richard S.; Wong, Wayne A.; Hepp, Aloysius F.

    2010-01-01

    An evaluation of several solar concentrator-based systems for producing oxygen from lunar regolith was performed. The systems utilize a solar concentrator mirror to provide thermal energy for the oxygen production process. Thermal energy to power a Stirling heat engine and photovoltaics are compared for the production of electricity. The electricity produced is utilized to operate the equipment needed in the oxygen production process. The initial oxygen production method utilized in the analysis is hydrogen reduction of ilmenite. Utilizing this method of oxygen production a baseline system design was produced. This baseline system had an oxygen production rate of 0.6 kg/hr with a concentrator mirror size of 5 m. Variations were performed on the baseline design to show how changes in the system size and process (rate) affected the oxygen production rate. An evaluation of the power requirements for a carbothermal lunar regolith reduction reactor has also been conducted. The reactor had a total power requirement between 8,320 to 9,961 W when producing 1000 kg/year of oxygen. The solar concentrator used to provide the thermal power (over 82 percent of the total energy requirement) would have a diameter of less than 4 m.

  15. 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.

  16. Solar energy thermally powered electrical generating system

    NASA Technical Reports Server (NTRS)

    Owens, William R. (Inventor)

    1989-01-01

    A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

  17. 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.

  18. 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.

  19. Spectroscopic measurements of solar wind generation

    NASA Technical Reports Server (NTRS)

    Kohl, J. L.; Withbroe, G. L.; Zapata, C. A.; Noci, G.

    1983-01-01

    Spectroscopically observable quantities are described which are sensitive to the primary plasma parameters of the solar wind's source region. The method is discussed in which those observable quantities are used as constraints in the construction of empirical models of various coronal structures. Simulated observations are used to examine the fractional contributions to observed spectral intensities from coronal structures of interest which co-exist with other coronal structures along simulated lines-of-sight. The sensitivity of spectroscopic observables to the physical parameters within each of those structures is discussed.

  20. Modeling and analysis of solar distributed generation

    NASA Astrophysics Data System (ADS)

    Ortiz Rivera, Eduardo Ivan

    Recent changes in the global economy are creating a big impact in our daily life. The price of oil is increasing and the number of reserves are less every day. Also, dramatic demographic changes are impacting the viability of the electric infrastructure and ultimately the economic future of the industry. These are some of the reasons that many countries are looking for alternative energy to produce electric energy. The most common form of green energy in our daily life is solar energy. To convert solar energy into electrical energy is required solar panels, dc-dc converters, power control, sensors, and inverters. In this work, a photovoltaic module, PVM, model using the electrical characteristics provided by the manufacturer data sheet is presented for power system applications. Experimental results from testing are showed, verifying the proposed PVM model. Also in this work, three maximum power point tracker, MPPT, algorithms would be presented to obtain the maximum power from a PVM. The first MPPT algorithm is a method based on the Rolle's and Lagrange's Theorems and can provide at least an approximate answer to a family of transcendental functions that cannot be solved using differential calculus. The second MPPT algorithm is based on the approximation of the proposed PVM model using fractional polynomials where the shape, boundary conditions and performance of the proposed PVM model are satisfied. The third MPPT algorithm is based in the determination of the optimal duty cycle for a dc-dc converter and the previous knowledge of the load or load matching conditions. Also, four algorithms to calculate the effective irradiance level and temperature over a photovoltaic module are presented in this work. The main reasons to develop these algorithms are for monitoring climate conditions, the elimination of temperature and solar irradiance sensors, reductions in cost for a photovoltaic inverter system, and development of new algorithms to be integrated with maximum

  1. Thermal analysis of solar biomass hybrid co-generation plants

    NASA Astrophysics Data System (ADS)

    Kaushika, N. D.; Mishra, Anuradha; Chakravarty, M. N.

    2005-12-01

    This article describes a co-generation plant based on the biogas being produced from the waste of distillery plant and highlights the possible configuration in which the plant can be hybridized with auxiliary solar energy source having the advantage of using financial incentives in several countries. In hybridization, the solar heat is used for heating the boiler feed water. The solar heat-generating unit consists of line focus parabolic trough collector, heat transportation system and heat delivery unit such as heat exchanger. The simulation model of heat and mass transfer processes in the solar field as well as the balance of the system is developed to investigate the technological feasibility of the concept in terms of plant yield and matching of subsystems.

  2. Solar generated quasi-biennial geomagnetic variation

    NASA Technical Reports Server (NTRS)

    Sugiura, M.; Poros, D. J.

    1977-01-01

    The existence of highly correlated quasi-biennial variations in the geomagnetic field and in solar activity is demonstrated. The analysis uses a numerical filter technique applied to monthly averages of the geomagnetic horizontal component and of the Zurich relative sunspot number. Striking correlations are found between the quasi-biennial geomagnetic variations determined from several magnetic observatories located at widely different longitudes, indicating a worldwide nature of the obtained variation. The correlation coefficient between the filtered Dst index and the filtered relative sunspot number is found to be -0.79 at confidence level greater than 99% with a time-lag of 4 months, with solar activity preceding the Dst variation. The correlation between the unfiltered data of Dst and of the sunspot number is also high with a similar time-lag. Such a timelag has not been discussed in the literature, and a further study is required to establish the mode of sun-earth relationship that gives this time delay.

  3. 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.

  4. 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.

    2016-10-01

    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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Solar thermal organic rankine cycle for micro-generation

    NASA Astrophysics Data System (ADS)

    Alkahli, N. A.; Abdullah, H.; Darus, A. N.; Jalaludin, A. F.

    2012-06-01

    The conceptual design of an Organic Rankine Cycle (ORC) driven by solar thermal energy is developed for the decentralized production of electricity of up to 50 kW. Conventional Rankine Cycle uses water as the working fluid whereas ORC uses organic compound as the working fluid and it is particularly suitable for low temperature applications. The ORC and the solar collector will be sized according to the solar flux distribution in the Republic of Yemen for the required power output of 50 kW. This will be a micro power generation system that consists of two cycles, the solar thermal cycle that harness solar energy and the power cycle, which is the ORC that generates electricity. As for the solar thermal cycle, heat transfer fluid (HTF) circulates the cycle while absorbing thermal energy from the sun through a parabolic trough collector and then storing it in a thermal storage to increase system efficiency and maintains system operation during low radiation. The heat is then transferred to the organic fluid in the ORC via a heat exchanger. The organic fluids to be used and analyzed in the ORC are hydrocarbons R600a and R290.

  11. Multiple Exciton Generation for Highly Efficient Solar Cells

    NASA Astrophysics Data System (ADS)

    Nozik, Arthur

    2007-03-01

    In order to utilize solar power for the production of electricity and fuel on a massive scale, it will be necessary to develop solar photon conversion systems that have an appropriate combination of high efficiency and low capital cost (/m^2). One new potential approach to high solar cell efficiency is to utilize the unique properties of semiconductor quantum dot nanostructures to control the relaxation dynamics of photogenerated carriers to produce either enhanced photocurrent through efficient multiple exciton generation (MEG) or enhanced photopotential through hot electron transport and transfer processes. To achieve these desirable effects it is necessary to understand and control the dynamics of electron relaxation, cooling, multiple exciton generation , transport, and interfacial electron transfer of the photogenerated carriers with fs to ns time resolution. We have been studying these fundamental dynamics in bulk and nanoscale semiconductors (quantum dots, quantum wires, and quantum wells) using femtosecond transient absorption, photoluminescence, and THz spectroscopy. This work will be summarized and recent advances in creating multiple excitons from a single photon will be discussed, including a unique model to explain efficient MEG based on the coherent superposition of multiple excitonic states. Various possible configurations for quantum dot solar cells that could produce ultra-high conversion efficiencies for the production of electricity, as well as for producing solar fuels (for example, hydrogen from water splitting), will be discussed, along with associated thermodynamic calculations that show the increase in the maximum theoretical gain in solar photon conversion efficiency for both electricity and fuel production.

  12. Solar powered Stirling cycle electrical generator

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.

    1991-01-01

    Under NASA's Civil Space Technology Initiative (CSTI), the NASA Lewis Research Center is developing the technology needed for free-piston Stirling engines as a candidate power source for space systems in the late 1990's and into the next century. Space power requirements include high efficiency, very long life, high reliability, and low vibration. Furthermore, system weight and operating temperature are important. The free-piston Stirling engine has the potential for a highly reliable engine with long life because it has only a few moving parts, non-contacting gas bearings, and can be hermetically sealed. These attributes of the free-piston Stirling engine also make it a viable candidate for terrestrial applications. In cooperation with the Department of Energy, system designs are currently being completed that feature the free-piston Stirling engine for terrestrial applications. Industry teams were assembled and are currently completing designs for two Advanced Stirling Conversion Systems utilizing technology being developed under the NASA CSTI Program. These systems, when coupled with a parabolic mirror to collect the solar energy, are capable of producing about 25 kW of electricity to a utility grid. Industry has identified a niche market for dish Stirling systems for worldwide remote power application. They believe that these niche markets may play a major role in the introduction of Stirling products into the commercial market.

  13. DAPHNE: Energy Generation and storage, using Solar Sails

    NASA Astrophysics Data System (ADS)

    Argelagós Palau, Ana Maria; Savio Bradford, Brandon

    Space travel is still in it's adolescent stages. Having embarked beyond the limit of our atmosphere for a mere 50 years, it is easy to imagine how much is yet to be discovered, in other solar systems and our own. One of the main factors that slow us down is the need for Energy. Long distance space travel requires a lot of energy, both for propulsion and operations alike. The principle of solar sails shows that the momentum of solar energy can be used beneficially, as can be seen in NASA's Sun-Jammer project. So, why not generate energy from this system? The DAPHNE system will utilize the simple principle of wind mills that is used here on Earth; using the force created by Solar wind to rotate an axle that in turn, generates energy. And this mill can be used to recharge spacecraft that need to fly further than it's own initial energy system will allow. Another benefit to developing this system is the fact that it is an alternative to nuclear energy generation for space, that a lot of modern research is being done on. The DAPHNE system can be considered a solution to long term propellant storage in space for interplanetary and interstellar travel. This paper proposes the design of an energy recharge technology, we called DAPHNE, which will utilize Nanotechnology, using solar sails to generate and store energy for future long-distance space craft to dock with, recharge and continue on their journey/mission. Examples of spacecraft in development that might benefit from a recharging station are the LISA Pathfinder, terrestrial exploration missions and eventually, the long interstellar missions that will be launched in the distant future. Thereby, allowing mankind to push the boundaries of our solar system and accelerate our ability to know what's out there. This technology would help the future generations of Space researchers move further than we can.

  14. Treatment of Solar Generation in Electric Utility Resource Planning

    SciTech Connect

    Sterling, J.; McLaren, J.; Taylor, M.; Cory, K.

    2013-10-01

    Today's utility planners have a different market and economic context than their predecessors, including planning for the growth of renewable energy. State and federal support policies, solar photovoltaic (PV) price declines, and the introduction of new business models for solar PV 'ownership' are leading to increasing interest in solar technologies (especially PV); however, solar introduces myriad new variables into the utility resource planning decision. Most, but not all, utility planners have less experience analyzing solar than conventional generation as part of capacity planning, portfolio evaluation, and resource procurement decisions. To begin to build this knowledge, utility staff expressed interest in one effort: utility exchanges regarding data, methods, challenges, and solutions for incorporating solar in the planning process. Through interviews and a questionnaire, this report aims to begin this exchange of information and capture utility-provided information about: 1) how various utilities approach long-range resource planning; 2) methods and tools utilities use to conduct resource planning; and, 3) how solar technologies are considered in the resource planning process.

  15. Holographic window for solar power generation

    NASA Astrophysics Data System (ADS)

    Kasezawa, Toshihiro; Horimai, Hideyoshi; Tabuchi, Hiroshi; Shimura, Tsutomu

    2016-12-01

    A new photovoltaic generation unit based on the application of holographic technologies called a Holo-Window is proposed in this work. The basic principle and the optical configuration used for the basic experimental unit are described. Suitable fabrication technology for a hologram with the broadband spectrum required to provide the appropriate sunlight capture capability is then discussed. Finally, a laboratory-prototype Holo-Window unit was developed and its performance was evaluated.

  16. Solar electricity supply isolines of generation capacity and storage.

    PubMed

    Grossmann, Wolf; Grossmann, Iris; Steininger, Karl W

    2015-03-24

    The recent sharp drop in the cost of photovoltaic (PV) electricity generation accompanied by globally rapidly increasing investment in PV plants calls for new planning and management tools for large-scale distributed solar networks. Of major importance are methods to overcome intermittency of solar electricity, i.e., to provide dispatchable electricity at minimal costs. We find that pairs of electricity generation capacity G and storage S that give dispatchable electricity and are minimal with respect to S for a given G exhibit a smooth relationship of mutual substitutability between G and S. These isolines between G and S support the solving of several tasks, including the optimal sizing of generation capacity and storage, optimal siting of solar parks, optimal connections of solar parks across time zones for minimizing intermittency, and management of storage in situations of far below average insolation to provide dispatchable electricity. G-S isolines allow determining the cost-optimal pair (G,S) as a function of the cost ratio of G and S. G-S isolines provide a method for evaluating the effect of geographic spread and time zone coverage on costs of solar electricity.

  17. Modelling solar irradiance from HRV images of Meteosat Second Generation

    NASA Astrophysics Data System (ADS)

    Cony, Marco; Zarzalejo, Luis; Polo, Jesús; Marchante, Ruth; Martín, Luis

    2010-05-01

    Knowledge of solar radiation at the earth's surface is a need in designing any solar energy application. In particular both photovoltaic and solar thermal systems required high accurate data of solar radiation components. Nowadays the use of satellite images as input to models for deriving solar irradiance time series is accepted as a reliable methodology with good accuracy. In this sense, there are several models aimed at this objective. Among them it can be pointed out the Heliosat-2 method, based upon the first generation of Meteosat satellites, which has been broadly used. Taken this approach as reference a modified model was proposed including additional independent variables to the cloud index, such as the moments of the cloud index distribution and the air mass. This model was successfully assessed with about 30 ground data sites in Spain showing a good response. However, since 2006 the Meteosat Second Generation (MSG) is observing the earth-atmosphere system centred in zero longitude. This new satellite generation has improved technical characteristics compared to the former one, particularly those focused on radiometric, spectral, spatial and time resolutions. This work is aimed at describing the work to accommodate the former model based on Heliosat-2 to operate with the MSG images and characteristics. A comparison with the old model will be made in the overlapping period, 2006, and an assessment with available ground data will also be performed as well.

  18. Solar electricity supply isolines of generation capacity and storage

    PubMed Central

    Grossmann, Wolf; Grossmann, Iris; Steininger, Karl W.

    2015-01-01

    The recent sharp drop in the cost of photovoltaic (PV) electricity generation accompanied by globally rapidly increasing investment in PV plants calls for new planning and management tools for large-scale distributed solar networks. Of major importance are methods to overcome intermittency of solar electricity, i.e., to provide dispatchable electricity at minimal costs. We find that pairs of electricity generation capacity G and storage S that give dispatchable electricity and are minimal with respect to S for a given G exhibit a smooth relationship of mutual substitutability between G and S. These isolines between G and S support the solving of several tasks, including the optimal sizing of generation capacity and storage, optimal siting of solar parks, optimal connections of solar parks across time zones for minimizing intermittency, and management of storage in situations of far below average insolation to provide dispatchable electricity. G−S isolines allow determining the cost-optimal pair (G,S) as a function of the cost ratio of G and S. G−S isolines provide a method for evaluating the effect of geographic spread and time zone coverage on costs of solar electricity. PMID:25755261

  19. 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.

  20. 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.

  1. 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.

  2. Optimal Solar PV Arrays Integration for Distributed Generation

    SciTech Connect

    Omitaomu, Olufemi A; Li, Xueping

    2012-01-01

    Solar photovoltaic (PV) systems hold great potential for distributed energy generation by installing PV panels on rooftops of residential and commercial buildings. Yet challenges arise along with the variability and non-dispatchability of the PV systems that affect the stability of the grid and the economics of the PV system. This paper investigates the integration of PV arrays for distributed generation applications by identifying a combination of buildings that will maximize solar energy output and minimize system variability. Particularly, we propose mean-variance optimization models to choose suitable rooftops for PV integration based on Markowitz mean-variance portfolio selection model. We further introduce quantity and cardinality constraints to result in a mixed integer quadratic programming problem. Case studies based on real data are presented. An efficient frontier is obtained for sample data that allows decision makers to choose a desired solar energy generation level with a comfortable variability tolerance level. Sensitivity analysis is conducted to show the tradeoffs between solar PV energy generation potential and variability.

  3. 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.

  4. 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.

  5. Thermoelectric instability induced by single pulses and alternating currents in second-generation superconducting tapes

    NASA Astrophysics Data System (ADS)

    Degtyarenko, P. N.; Dul'kin, I. N.; Fisher, L. M.; Kalinov, A. V.; Voloshin, I. F.; Yampol'skii, V. A.

    2011-02-01

    We have studied current flow instabilities in a second-generation superconducting tapes and the transition of the tapes into the resistive state. Contrary to the usual quasisteady instability regimes, here we consider the adiabatic case in which the sample is heated rapidly. Two kinds of measurements of the current-voltage characteristics (CVC) have been made, specifically, with excitation of the tape by a single sinusoidal current pulse I (t)=I0sin(ωt) at different amplitudes I0 and by a continuous ac current. The main results were obtained for current amplitudes I0 exceeding the critical current Ic. We find that the dynamic CVC are essentially reversible for low amplitudes, whereas they become irreversible and acquire an N-shape for higher current amplitudes. The dynamic CVC change radically if the dissipated energy attains a threshold value Wth roughly equal to 5mJ/cm for our tapes. When this energy is reached, the tape undergoes a transition to the resistive state owing to formation of normal domains. The development of the instability with steady ac currents was studied at relatively small amplitudes such that the energy dissipated per half cycle is much lower than Wth. Even in this case, a tape undergoes a transition to the resistive state because of energy accumulation (heat pumping). With this pumping, the transition takes place after a definite number of ac cycles, when the total accumulated energy reaches the same threshold value Wth. The specific features of the dynamic CVC are interpreted qualitatively, with the appearance of resistive domains taken into account. Estimates based on the CVC agree well with our experimental data. These results can be useful in the design of superconducting fault current limiters.

  6. 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

  7. Band engineering of thermoelectric materials.

    PubMed

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

    2012-12-04

    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.

  8. Advanced Thermophotovoltaic Cells Modeling, Optimized for Use in Radioisotope Thermoelectric Generators (RTGs) for Mars and Deep Space Missions

    DTIC Science & Technology

    2004-06-01

    GaSb Solar Cell................................................................................................58 Figure 31. GaSb Solar Cell I - V Characteristics...61 Figure 34. InGaAs Solar Cell I - V Characteristics .............................................................61 Figure 35...curve of the cell. Figure 8. Current in a Solar Cell [After Ref. 5] Figure 9 shows an example of a solar cell I - V curve. The points on this

  9. Integrated photoelectrochemical energy storage: solar hydrogen generation and supercapacitor.

    PubMed

    Xia, Xinhui; Luo, Jingshan; Zeng, Zhiyuan; Guan, Cao; Zhang, Yongqi; Tu, Jiangping; Zhang, Hua; Fan, Hong Jin

    2012-01-01

    Current solar energy harvest and storage are so far realized by independent technologies (such as solar cell and batteries), by which only a fraction of solar energy is utilized. It is highly desirable to improve the utilization efficiency of solar energy. Here, we construct an integrated photoelectrochemical device with simultaneous supercapacitor and hydrogen evolution functions based on TiO(2)/transition metal hydroxides/oxides core/shell nanorod arrays. The feasibility of solar-driven pseudocapacitance is clearly demonstrated, and the charge/discharge is indicated by reversible color changes (photochromism). In such an integrated device, the photogenerated electrons are utilized for H(2) generation and holes for pseudocapacitive charging, so that both the reductive and oxidative energies are captured and converted. Specific capacitances of 482 F g(-1) at 0.5 A g(-1) and 287 F g(-1) at 1 A g(-1) are obtained with TiO(2)/Ni(OH)(2) nanorod arrays. This study provides a new research strategy for integrated pseudocapacitor and solar energy application.

  10. 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

  11. Dispersed solar thermal generation employing parabolic dish-electric transport with field modulated generator systems

    NASA Technical Reports Server (NTRS)

    Ramakumar, R.; Bahrami, K.

    1981-01-01

    This paper discusses the application of field modulated generator systems (FMGS) to dispersed solar-thermal-electric generation from a parabolic dish field with electric transport. Each solar generation unit is rated at 15 kWe and the power generated by an array of such units is electrically collected for insertion into an existing utility grid. Such an approach appears to be most suitable when the heat engine rotational speeds are high (greater than 6000 r/min) and, in particular, if they are operated in the variable speed mode and if utility-grade a.c. is required for direct insertion into the grid without an intermediate electric energy storage and reconversion system. Predictions of overall efficiencies based on conservative efficiency figures for the FMGS are in the range of 25 per cent and should be encouraging to those involved in the development of cost-effective dispersed solar thermal power systems.

  12. Lossless hybridization between photovoltaic and thermoelectric devices.

    PubMed

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

    2013-01-01

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

  13. Lossless hybridization between photovoltaic and thermoelectric devices

    PubMed Central

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

    2013-01-01

    The optimal hybridization of photovoltaic (PV) and thermoelectric (TE) devices has long been considered ideal for the efficient harnessing solar energy. Our hybrid approach uses full spectrum solar energy via lossless coupling between PV and TE devices while collecting waste energy from thermalization and transmission losses from PV devices. Achieving lossless coupling makes the power output from the hybrid device equal to the sum of the maximum power outputs produced separately from individual PV and TE devices. TE devices need to have low internal resistances enough to convey photo-generated currents without sacrificing the PV fill factor. Concomitantly, a large number of p-n legs are preferred to drive a high Seebeck voltage in TE. Our simple method of attaching a TE device to a PV device has greatly improved the conversion efficiency and power output of the PV device (~30% at a 15°C temperature gradient across a TE device). PMID:23820973

  14. Power Generator with Thermo-Differential Modules

    NASA Technical Reports Server (NTRS)

    Saiz, John R.; Nguyen, James

    2010-01-01

    A thermoelectric power generator consists of an oven box and a solar cooker/solar reflector unit. The solar reflector concentrates sunlight into heat and transfers the heat into the oven box via a heat pipe. The oven box unit is surrounded by five thermoelectric modules and is located at the bottom end of the solar reflector. When the heat is pumped into one side of the thermoelectric module and ejected from the opposite side at ambient temperatures, an electrical current is produced. Typical temperature accumulation in the solar reflector is approximately 200 C (392 F). The heat pipe then transfers heat into the oven box with a loss of about 40 percent. At the ambient temperature of about 20 C (68 F), the temperature differential is about 100 C (180 F) apart. Each thermoelectric module, generates about 6 watts of power. One oven box with five thermoelectric modules produces about 30 watts. The system provides power for unattended instruments in remote areas, such as space colonies and space vehicles, and in polar and other remote regions on Earth.

  15. 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.

  16. Graphene-Based Photocatalysts for Solar-Fuel Generation.

    PubMed

    Xiang, Quanjun; Cheng, Bei; Yu, Jiaguo

    2015-09-21

    The production of solar fuel through photocatalytic water splitting and CO2 reduction using photocatalysts has attracted considerable attention owing to the global energy shortage and growing environmental problems. During the past few years, many studies have demonstrated that graphene can markedly enhance the efficiency of photocatalysts for solar-fuel generation because of its unique 2D conjugated structure and electronic properties. Herein we summarize the recent advances in the application of graphene-based photocatalysts for solar-fuel production, including CO2 reduction to hydrocarbon fuel and water splitting to H2. A brief overview of the fundamental principles for splitting of water and reduction of CO2 is given. The different roles of graphene in these graphene-based photocatalysts for improving photocatalytic performance are discussed. Finally, the perspectives on the challenges and opportunities for future research in this promising area are also presented.

  17. SOLAR WIND STRAHL BROADENING BY SELF-GENERATED PLASMA WAVES

    SciTech Connect

    Pavan, J.; Gaelzer, R.; Vinas, A. F.; Yoon, P. H.; Ziebell, L. F. E-mail: rudi@ufpel.edu.br E-mail: yoonp@umd.edu

    2013-06-01

    This Letter reports on the results of numerical simulations which may provide a possible explanation for the strahl broadening during quiet solar conditions. The relevant processes involved in the broadening are due to kinetic quasi-linear wave-particle interaction. Making use of static analytical electron distribution in an inhomogeneous field, it is found that self-generated electrostatic waves at the plasma frequency, i.e., Langmuir waves, are capable of scattering the strahl component, resulting in energy and pitch-angle diffusion that broadens its velocity distribution significantly. The present theoretical results provide an alternative or complementary explanation to the usual whistler diffusion scenario, suggesting that self-induced electrostatic waves at the plasma frequency might play a key role in broadening the solar wind strahl during quiet solar conditions.

  18. Solar Wind Strahl Broadening by Self-Generated Plasma Waves

    NASA Technical Reports Server (NTRS)

    Pavan, J.; Vinas, A. F.; Yoon, P. H.; Ziebell, L. F.; Gaelzer, R.

    2013-01-01

    This Letter reports on the results of numerical simulations which may provide a possible explanation for the strahl broadening during quiet solar conditions. The relevant processes involved in the broadening are due to kinetic quasi-linear wave-particle interaction. Making use of static analytical electron distribution in an inhomogeneous field, it is found that self-generated electrostatic waves at the plasma frequency, i.e., Langmuir waves, are capable of scattering the strahl component, resulting in energy and pitch-angle diffusion that broadens its velocity distribution significantly. The present theoretical results provide an alternative or complementary explanation to the usual whistler diffusion scenario, suggesting that self-induced electrostatic waves at the plasma frequency might play a key role in broadening the solar wind strahl during quiet solar conditions.

  19. 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.

  20. Connection between solar activity cycles and grand minima generation

    NASA Astrophysics Data System (ADS)

    Vecchio, A.; Lepreti, F.; Laurenza, M.; Alberti, T.; Carbone, V.

    2017-03-01

    Aims: The revised dataset of sunspot and group numbers (released by WDC-SILSO) and the sunspot number reconstruction based on dendrochronologically dated radiocarbon concentrations have been analyzed to provide a deeper characterization of the solar activity main periodicities and to investigate the role of the Gleissberg and Suess cycles in the grand minima occurrence. Methods: Empirical mode decomposition (EMD) has been used to isolate the time behavior of the different solar activity periodicities. A general consistency among the results from all the analyzed datasets verifies the reliability of the EMD approach. Results: The analysis on the revised sunspot data indicates that the highest energy content is associated with the Schwabe cycle. In correspondence with the grand minima (Maunder and Dalton), the frequency of this cycle changes to longer timescales of 14 yr. The Gleissberg and Suess cycles, with timescales of 60-120 yr and 200-300 yr, respectively, represent the most energetic contribution to sunspot number reconstruction records and are both found to be characterized by multiple scales of oscillation. The grand minima generation and the origin of the two expected distinct types of grand minima, Maunder and longer Spörer-like, are naturally explained through the EMD approach. We found that the grand minima sequence is produced by the coupling between Gleissberg and Suess cycles, the latter being responsible for the most intense and longest Spörer-like minima (with typical duration longer than 80 yr). Finally, we identified a non-solar component, characterized by a very long scale oscillation of 7000 yr, and the Hallstatt cycle ( 2000 yr), likely due to the solar activity. Conclusions: These results provide new observational constraints on the properties of the solar cycle periodicities, the grand minima generation, and thus the long-term behavior of the solar dynamo.

  1. 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.

  2. 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.

  3. Dynamic conversion of solar generated heat to electricity

    NASA Technical Reports Server (NTRS)

    Powell, J. C.; Fourakis, E.; Hammer, J. M.; Smith, G. A.; Grosskreutz, J. C.; Mcbride, E.

    1974-01-01

    The effort undertaken during this program led to the selection of the water-superheated steam (850 psig/900 F) crescent central receiver as the preferred concept from among 11 candidate systems across the technological spectrum of the dynamic conversion of solar generated heat to electricity. The solar power plant designs were investigated in the range of plant capacities from 100 to 1000 Mw(e). The investigations considered the impacts of plant size, collector design, feed-water temperature ratio, heat rejection equipment, ground cover, and location on solar power technical and economic feasibility. For the distributed receiver systems, the optimization studies showed that plant capacities less than 100 Mw(e) may be best. Although the size of central receiver concepts was not parametrically investigated, all indications are that the optimal plant capacity for central receiver systems will be in the range from 50 to 200 Mw(e). Solar thermal power plant site selection criteria and methodology were also established and used to evaluate potentially suitable sites. The result of this effort was to identify a site south of Inyokern, California, as typically suitable for a solar thermal power plant. The criteria used in the selection process included insolation and climatological characteristics, topography, and seismic history as well as water availability.

  4. Post-flight investigation programmes of recently retrieved solar generators

    NASA Technical Reports Server (NTRS)

    Grelach, Lothar

    1994-01-01

    In 1993 two ESA solar power generators were successfully retrieved from space: EURECA with its 10 panel rigid array in August, after 11 months in a 500 km orbit, and one of the two flexible Hubble Space Telescope (HST) arrays in December, after almost 4 years in a 600 km orbit. Both solar generators are undergoing separate post-flight investigation programs (PFIP). These programs cover investigations of all solar array (SA) components and mechanisms. Since both programs have much in common, most of the component and material investigations are the same. Extremely valuable information on numerous essential subjects, such as atomic oxygen, radiation, meteoroid and space debris environment resulting damage, low cycle fatigue, material degradation, etc. are expected to be obtained for both types of arrays. We will also be able to explain and understand the anomalies experienced on both solar arrays in orbit. The paper will outline both post-flight investigation programs and will concentrate on reporting the first results and findings.

  5. 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.

  6. An approach to design a (90)Sr radioisotope thermoelectric generator using analytical and Monte Carlo methods with ANSYS, COMSOL, and MCNP.

    PubMed

    Khajepour, Abolhasan; Rahmani, Faezeh

    2017-01-01

    In this study, a (90)Sr radioisotope thermoelectric generator (RTG) with power of milliWatt was designed to operate in the determined temperature (300-312K). For this purpose, the combination of analytical and Monte Carlo methods with ANSYS and COMSOL software as well as the MCNP code was used. This designed RTG contains (90)Sr as a radioisotope heat source (RHS) and 127 coupled thermoelectric modules (TEMs) based on bismuth telluride. Kapton (2.45mm in thickness) and Cryotherm sheets (0.78mm in thickness) were selected as the thermal insulators of the RHS, as well as a stainless steel container was used as a generator chamber. The initial design of the RHS geometry was performed according to the amount of radioactive material (strontium titanate) as well as the heat transfer calculations and mechanical strength considerations. According to the Monte Carlo simulation performed by the MCNP code, approximately 0.35 kCi of (90)Sr is sufficient to generate heat power in the RHS. To determine the optimal design of the RTG, the distribution of temperature as well as the dissipated heat and input power to the module were calculated in different parts of the generator using the ANSYS software. Output voltage according to temperature distribution on TEM was calculated using COMSOL. Optimization of the dimension of the RHS and heat insulator was performed to adapt the average temperature of the hot plate of TEM to the determined hot temperature value. This designed RTG generates 8mW in power with an efficiency of 1%. This proposed approach of combination method can be used for the precise design of various types of RTGs.

  7. 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.

  8. High temperature thermoelectrics

    SciTech Connect

    Moczygemba, Joshua E.; Biershcenk, James L.; Sharp, Jeffrey W.

    2014-09-23

    In accordance with one embodiment of the present disclosure, a thermoelectric device includes a plurality of thermoelectric elements that each include a diffusion barrier. The diffusion barrier includes a refractory metal. The thermoelectric device also includes a plurality of conductors coupled to the plurality of thermoelectric elements. The plurality of conductors include aluminum. In addition, the thermoelectric device includes at least one plate coupled to the plurality of thermoelectric elements using a braze. The braze includes aluminum.

  9. Stabilization of Thermoelectric Properties of the Cu/Bi0.48Sb1.52Te3 Composite for Advantageous Power Generation

    NASA Astrophysics Data System (ADS)

    Xie, Dewen; Xu, Jingtao; Liu, Zhu; Liu, Guoqiang; Shao, Hezhu; Tan, Xiaojian; Jiang, Haochuan; Jiang, Jun

    2016-09-01

    Bi2Te3 thermoelectric materials have been developed for refrigeration around room temperature. But the ZT values decrease quickly above 400 K, which need to be improved for applications in power generation. In the present work, P-type Cu/BiSbTe alloys have been prepared via a zone melting method followed by spark plasma sintering. Due to the effects of Cu powders, the as-prepared materials exhibit a shift of the peak Seebeck coefficient value towards higher temperature and suppressed lattice thermal conductivity with increasing Cu powders. A peak ZT value as high as 0.87 has been obtained around 500 K in the BiSbTe alloy with 1 wt.% Cu powder addition, and the ZT values stabilize above 0.8 from 375 K to 550 K. This high and stable value for BiSbTe alloys at such a high temperature is very attractive for its application in power generation devices.

  10. Generation of a Solar Wind Ensemble for Space Weather Forecasting

    NASA Astrophysics Data System (ADS)

    Hassan, E.; Morley, S.; Steinberg, J. T.

    2015-12-01

    Knowing the upstream solar wind conditions is essential in forecasting the variations in the geomangetic field and the status of the Earth's ionosphere. Most data-driven simulations or data-assimilation codes, used for space weather forecasting, are based on the solar wind measurements at 1 AU, or more specifically at the first Lagrangian orbit (L1), such as observations from the Advanced Composition Explorer (ACE). However, L1 measurements may not represent the solar wind conditions just outside the magnetosphere. As a result, time-series measurements from L1 by themselves are not adequate to run simulations to derive probabilistic forecasts of the magnetosphere and ionosphere. To obtain confidence levels and uncertainty estimates, a solar wind ensemble data set is desirable. Therefore we used three years of measurements atACE advected using the flat delay method to the Interplanetary Monitoring Platform (IMP8) spacecraft location. Then, we compared both measurements to establish Kernel Density Estimation (KDE) functions for IMP8 measurements based on ACE measurements. In addition, we used a 4-categorization scheme to sort the incoming solar wind into ejecta, coronal-hole-origin, sector-reversal-regions, and streamer-belt-origin categories at both ACE and IMP8. We established the KDE functions for each category and compared with the uncategorized KDE functions. The location of the IMP8 spacecraft allows us to use these KDE functions to generate ensemble of solar wind data close to Earth's magnetopause. The ensemble can then be used to forecast the state of the geomagnetic field and the ionosphere.

  11. Nanostructures having high performance thermoelectric properties

    DOEpatents

    Yang, Peidong; Majumdar, Arunava; Hochbaum, Allon I; Chen, Renkun; Delgado, Raul Diaz

    2014-05-20

    The invention provides for a nanostructure, or an array of such nanostructures, each comprising a rough surface, and a doped or undoped semiconductor. The nanostructure is an one-dimensional (1-D) nanostructure, such a nanowire, or a two-dimensional (2-D) nanostructure. The nanostructure can be placed between two electrodes and used for thermoelectric power generation or thermoelectric cooling.

  12. 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.

  13. Nanostructures having high performance thermoelectric properties

    DOEpatents

    Yang, Peidong; Majumdar, Arunava; Hochbaum, Allon I.; Chen, Renkun; Delgado, Raul Diaz

    2015-12-22

    The invention provides for a nanostructure, or an array of such nanostructures, each comprising a rough surface, and a doped or undoped semiconductor. The nanostructure is an one-dimensional (1-D) nanostructure, such a nanowire, or a two-dimensional (2-D) nanostructure. The nanostructure can be placed between two electrodes and used for thermoelectric power generation or thermoelectric cooling.

  14. The Generation of Lighting in the Solar Nebula

    NASA Technical Reports Server (NTRS)

    Cuzzi, Jeffrey; Desch, S. J.; DeVincenzi, Donald (Technical Monitor)

    1998-01-01

    The process that melted and formed the chondrules, mm-sized glassy beads within meteorites, has not been conclusively identified. Origin by lightning in the solar nebula is consistent with many features of chondrules, but no viable model of lightning has yet been advanced. We present a model demonstrating how lightning could be generated in the solar nebula which differs from previous models in three important aspects. First, we identify a new', powerful charging mechanism that is based on the differences in contact potentials between particles of different composition, a form of triboelectric charging. In the presence of fine silicate grains and fine iron metal grains, large silicate particles (the chondrules) can acquire charges of +10(exp 5) e. Second, we assume that the chondrule precursor particles are selectively concentrated in clumps 1 - 100 km in size by the turbulent concentration mechanism described by Cuzzi et al. (1996). The concentration of these highly charged particles into clumps, in a background of negatively charged metal grains, is what generates the strong electric fields. Third, we make refinements in the estimates of the breakdown electric field and the ionization rate. We calculate that electric fields large enough to trigger breakdown easily could have existed over regions large enough (approx. 100km) to generate very large discharges of electrical energy (approx. 10(exp 16)erg). The discharges would have been sufficiently energetic and frequent to have formed the chondrules. We place constraints on the generation of lightning and conclude that it could not be generated if the abundance of Al-26 in chondrules was as high as the level in the CAls. This conclusion is consistent with isotopic analyses of chondrules. This possibly implies that Al-26 was non-uniformly distributed in the solar nebula or that the chondrules formed several Myr after the CAIs.

  15. Solar Electric Generating System II finite element analysis

    SciTech Connect

    Dohner, J.L.; Anderson, J.R.

    1994-04-01

    On June 2, 1992, Landers` earthquake struck the Solar Electric Generating System II, located in Daggett, California. The 30 megawatt power station, operated by the Daggett Leasing Corporation (DLC), suffered substantial damage due to structural failures in the solar farm. These failures consisted of the separation of sliding joints supporting a distribution of parabolic glass mirrors. At separation, the mirrors fell to the ground and broke. It was the desire of the DLC and the Solar Thermal Design Assistance Center (STDAC) of Sandia National Laboratories (SNL) and to redesign these joints so that, in the event of future quakes, costly breakage will be avoided. To accomplish this task, drawings of collector components were developed by the STDAC, from which a detailed finite element computer model of a solar collector was produced. This nonlinear dynamic model, which consisted of over 8,560 degrees of freedom, underwent model reduction to form a low order nonlinear dynamic model containing only 40 degrees of freedom. This model was then used as a design tool to estimate joint dynamics. Using this design tool, joint configurations were modified, and an acceptable joint redesign determined. The results of this analysis showed that the implementation of metal stops welded to support shafts for the purpose of preventing joint separation is a suitable joint redesign. Moreover, it was found that, for quakes of Landers` magnitude, mirror breakage due to enhanced vibration in the trough assembly is unlikely.

  16. Engineering Assessment of TEG and TEG/FC Technology Growth Potential. Phase I. Engineering Assessment of Existing Thermoelectric Generator Technology.

    DTIC Science & Technology

    1981-09-01

    based on demonstrated and predicted performance of the current 500-watt TEG units, we find that the 500-watt TEG meets the SLEEP ROC except that...kW applications, we find that the TEG will meet the SLEEP ROC except that: • | • The 10-kW AC unit will exceed the 650 pounds weight require...Instruments, Inc., (201) 388-3500. 14. T. M. Pinnel , "Feasibility Test of a Thermoelectric Power Source PP-6075," USA Airborne Communication and

  17. High-throughput Z T predictions of nanoporous bulk materials as next-generation thermoelectric materials: A material genome approach

    NASA Astrophysics Data System (ADS)

    Hao, Qing; Xu, Dongchao; Lu, Na; Zhao, Hongbo

    2016-05-01

    The advancement of computational tools for material property predictions enables a broad search of novel materials for various energy-related applications. However, challenges still exist in accurately predicting the mean free paths of electrons and phonons in a high-throughput frame for thermoelectric property predictions, which largely hinders the computation-driven material search for novel materials. In this work, this need is eliminated under the limit of reduced nanostructure size within a bulk material, in which these mean free paths are restricted by the nanostructure size. A criterion for Z T evaluation is proposed for general nanoporous bulk materials and is demonstrated with representative oxides.

  18. 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

  19. Solar generator performance with load matching to water electrolysis

    NASA Astrophysics Data System (ADS)

    Freudenberg, K.

    1982-08-01

    A 7 W generator, based on monocrystalline silicon solar cells, was directly wired to an electronic load, simulating the current-voltage characteristic of an advanced water electrolyzer. System performance was monitored from January 15 to July 7, 1980. Measurements included current and voltage at the load and at the point of maximum power output, global irradiance and ambient temperature. Solar generator efficiency ranged from 7.5% to 11.5%. A large spread of + or - 1% in instantaneous generator efficiency was observed at identical values of global irradiance and ambient temperature. The dependence of the average generator efficiency on global irradiance and ambient temperature is given by a simple relation to an accuracy of + or - 0.2%. Load matching was optimized for high global irradiance at high ambient temperature. Averaged over the half year, period losses by nonideal load matching amounted to only 8.9%. Assuming an ideal current efficiency of the simulated water electrolyzer, the overall efficiency of hydrogen production was 8.0%.

  20. 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.

  1. Tax barriers to solar central receiver generation technology

    SciTech Connect

    Jenkins, A.F.; Reilly, H.E.

    1994-12-31

    Tax loads and required revenues are estimated for current and future solar central receiver and gas-fired plants competing in the same market. An economic measure of tax equity is used to evaluate the equity of the tax loads under past and present tax codes. The same measure is used to devise a tax strategy which produces the following two types of equitable taxation: (1) the two plants carry nearly equal tax loads, and (2) local, state and federal governments receive the same distribution of revenues from the solar plant as from the gas-fired plant `Me results show that central receivers (and likely other capital-intensive technologies) carry higher tax loads compared to competing gasfired generation, that tax loads are highly correlated with competitiveness, and that equitable taxation is feasible within the boundaries of the study.

  2. Development of a low cost, portable solar hydrogen generation device

    NASA Astrophysics Data System (ADS)

    Rose, Kyle; Aggarwal, M. D.; Batra, Ashok; Wingo, Dennis

    2014-10-01

    Hydrogen is a clean energy source that is environmentally friendly and safe. It is well known that electrolysis is a common method used to produce hydrogen. Other high cost methods for hydrogen production can be countered by the development of this low cost pulse width modulated circuit, using direct current provided by naturally existing solar energy as a power source. Efforts are being made in the scientific community to produce a low cost, portable, solar hydrogen generating device for a number of clean energy applications such as fuel cells and energy storage. Proof of concept has already been tested in the laboratory and a small prototype system is being designed and fabricated in the workshop at Alabama A&M University. Our results of this study and details of the electronic circuit and the prototype are presented.

  3. Maximum Potential of the Car Cabin Temperature in the Outdoor Parking Conditions as a Source of Energy in Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Sunawar, A.; Garniwa, I.

    2017-03-01

    Cars using the principle of converting heat energy into mechanical energy, but a lot of wasted heat energy not entirely transformed into mechanical energy, studies have been conducted that converts the heat energy into electrical energy using the principle thermoelectrically. However, there are many other energies that can be harnessed from the car, such as when the car is parked in the sun or driving in the heat of the sun, the temperature in the cabin can reach 80 degrees Celsius. The heat can be harmful to humans and the children immediately into the vehicle, as well as for the goods stored in the cabin if it contains toxins can evaporate because of the heat and dangerous. The danger can be prevented by reducing the heat in the cabin and transform into other forms of energy such as electricity. By providing a temperature difference of 40 degrees on the cold side of the module can be acquired electricity thermoelectrically up to 0.17W for one of its module, if it is made a module block the energy produced is enough to lower the temperature and charge batteries for further cooling. This study will use experiment method to get the maximum drop in temperature in the car cabin

  4. Economic considerations of utilizing small wind generators

    NASA Technical Reports Server (NTRS)

    Dodge, R.

    1973-01-01

    The economic feasibility of small wind generators is compared to that of solar cells, primary batteries, thermoelectric generators, and engine generators. It is shown that small wind generator plants offer an attractive alternative to primary battery systems and constantly running engines to generate power in remote areas. The limitation is an annual average wind velocity of at least 9 to 10 mph. Presently available units are most useful in the average load range of 10 to 1000 watts.

  5. High-Efficiency, Multijunction Solar Cells for Large-Scale Solar Electricity Generation

    NASA Astrophysics Data System (ADS)

    Kurtz, Sarah

    2006-03-01

    A solar cell with an infinite number of materials (matched to the solar spectrum) has a theoretical efficiency limit of 68%. If sunlight is concentrated, this limit increases to about 87%. These theoretical limits are calculated using basic physics and are independent of the details of the materials. In practice, the challenge of achieving high efficiency depends on identifying materials that can effectively use the solar spectrum. Impressive progress has been made with the current efficiency record being 39%. Today's solar market is also showing impressive progress, but is still hindered by high prices. One strategy for reducing cost is to use lenses or mirrors to focus the light on small solar cells. In this case, the system cost is dominated by the cost of the relatively inexpensive optics. The value of the optics increases with the efficiency of the solar cell. Thus, a concentrator system made with 35%- 40%-efficient solar cells is expected to deliver 50% more power at a similar cost when compare with a system using 25%-efficient cells. Today's markets are showing an opportunity for large concentrator systems that didn't exist 5-10 years ago. Efficiencies may soon pass 40% and ultimately may reach 50%, providing a pathway to improved performance and decreased cost. Many companies are currently investigating this technology for large-scale electricity generation. The presentation will cover the basic physics and more practical considerations to achieving high efficiency as well as describing the current status of the concentrator industry. This work has been authored by an employee of the Midwest Research Institute under Contract No. DE- AC36-99GO10337 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow

  6. Multiple exciton generation in nanocrystalline solar cells (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Boehm, Marcus; Davis, Nathaniel; Greenham, Neil C.

    2016-09-01

    Multiple exciton generation (MEG) - a process in which multiple charge-carrier pairs are generated from a single optical excitation - is a promising way to improve the photocurrent in photovoltaic devices and offers the potential of breaking the Shockley-Queisser limit. It remains, however, challenging to harvest charge-carrier pairs generated by MEG in working solar cells. Initial yields of additional carrier pairs may be reduced due to ultra-fast intraband relaxation processes, which compete with MEG at early times. Quantum dots of materials, which display reduced carrier cooling rates (e.g. PbTe)[1] or one-dimensional nanostructures (e.g. nano rods)[2] which accelerate the carrier multiplication process are therefore promising candidates to increase the impact of MEG in photovoltaic devices. Here we show that both theorised strategies can lead to solar cells, which produce extractable charge carrier pairs with an external quantum efficiency above 120%, and we estimate an internal quantum efficiency exceeding 150%. Resolving the charge carrier kinetics on the ultra-fast timescale with pump-probe transient absorption and pump-push-photocurrent measurements, we identify a delayed cooling effect above the experimentally- determined threshold energy for MEG[1].

  7. Prospects of Graphene as a Potential Carrier-Transport Material in Third-Generation Solar Cells.

    PubMed

    Chowdhury, Towhid H; Islam, Ashraful; Mahmud Hasan, A K; Terdi, M Asri Mat; Arunakumari, M; Prakash Singh, Surya; Alam, Md Khorshed; Bedja, Idriss M; Hafidz Ruslan, Mohd; Sopian, Kamaruzzaman; Amin, Nowshad; Akhtaruzzaman, Md

    2016-04-01

    Third-generation solar cells are understood to be the pathway to overcoming the issues and drawbacks of the existing solar cell technologies. Since the introduction of graphene in solar cells, it has been providing attractive properties for the next generation of solar cells. Currently, there are more theoretical predictions rather than practical recognitions in third-generation solar cells. Some of the potential of graphene has been explored in organic photovoltaics (OPVs) and dye-sensitized solar cells (DSSCs), but it has yet to be fully comprehended in the recent third-generation inorganic-organic hybrid perovskite solar cells. In this review, the diverse role of graphene in third-generation OPVs and DSSCs will be deliberated to provide an insight on the prospects and challenges of graphene in inorganic-organic hybrid perovskite solar cells.

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

    SciTech Connect

    John Rodgers; James Castle

    2008-08-31

    This study assessed opportunities for improving water quality associated with coal-fired power generation including the use of non-traditional waters for cooling, innovative technology for recovering and reusing water within power plants, novel approaches for the removal of trace inorganic compounds from ash pond effluents, and novel approaches for removing biocides from cooling tower blowdown. This research evaluated specifically designed pilot-scale constructed wetland systems for treatment of targeted constituents in non-traditional waters for reuse in thermoelectric power generation and other purposes. The overall objective of this project was to decrease targeted constituents in non-traditional waters to achieve reuse criteria or discharge limitations established by the National Pollutant Discharge Elimination System (NPDES) and Clean Water Act (CWA). The six original project objectives were completed, and results are presented in this final technical report. These objectives included identification of targeted constituents for treatment in four non-traditional water sources, determination of reuse or discharge criteria for treatment, design of constructed wetland treatment systems for these non-traditional waters, and measurement of treatment of targeted constituents in non-traditional waters, as well as determination of the suitability of the treated non-traditional waters for reuse or discharge to receiving aquatic systems. The four non-traditional waters used to accomplish these objectives were ash basin water, cooling water, flue gas desulfurization (FGD) water, and produced water. The contaminants of concern identified in ash basin waters were arsenic, chromium, copper, mercury, selenium, and zinc. Contaminants of concern in cooling waters included free oxidants (chlorine, bromine, and peroxides), copper, lead, zinc, pH, and total dissolved solids. FGD waters contained contaminants of concern including arsenic, boron, chlorides, selenium, mercury

  9. Phase transition enhanced thermoelectric figure-of-merit in copper chalcogenides

    NASA Astrophysics Data System (ADS)

    Brown, David R.; Day, Tristan; Borup, Kasper A.; Christensen, Sebastian; Iversen, Bo B.; Snyder, G. Jeffrey

    2013-11-01

    While thermoelectric materials can be used for solid state cooling, waste heat recovery, and solar electricity generation, low values of the thermoelectric figure of merit, zT, have led to an efficiency too low for widespread use. Thermoelectric effects are characterized by the Seebeck coefficient or thermopower, which is related to the entropy associated with charge transport. For example, coupling spin entropy with the presence of charge carriers has enabled the enhancement of zT in cobalt oxides. We demonstrate that the coupling of a continuous phase transition to carrier transport in Cu2Se over a broad (360-410 K) temperature range results in a dramatic peak in thermopower, an increase in phonon and electron scattering, and a corresponding doubling of zT (to 0.7 at 406 K), and a similar but larger increase over a wider temperature range in the zT of Cu1.97Ag.03Se (almost 1.0 at 400 K). The use of structural entropy for enhanced thermopower could lead to new engineering approaches for thermoelectric materials with high zT and new green applications for thermoelectrics.

  10. Phase transition enhanced thermoelectric figure-of-merit in copper chalcogenides

    SciTech Connect

    Brown, David R.; Day, Tristan; Snyder, G. Jeffrey; Borup, Kasper A.; Christensen, Sebastian; Iversen, Bo B.

    2013-11-01

    While thermoelectric materials can be used for solid state cooling, waste heat recovery, and solar electricity generation, low values of the thermoelectric figure of merit, zT, have led to an efficiency too low for widespread use. Thermoelectric effects are characterized by the Seebeck coefficient or thermopower, which is related to the entropy associated with charge transport. For example, coupling spin entropy with the presence of charge carriers has enabled the enhancement of zT in cobalt oxides. We demonstrate that the coupling of a continuous phase transition to carrier transport in Cu{sub 2}Se over a broad (360–410 K) temperature range results in a dramatic peak in thermopower, an increase in phonon and electron scattering, and a corresponding doubling of zT (to 0.7 at 406 K), and a similar but larger increase over a wider temperature range in the zT of Cu{sub 1.97}Ag{sub .03}Se (almost 1.0 at 400 K). The use of structural entropy for enhanced thermopower could lead to new engineering approaches for thermoelectric materials with high zT and new green applications for thermoelectrics.

  11. First generation solar adaptive optics system for 1-m New Vacuum Solar Telescope at Fuxian Solar Observatory

    NASA Astrophysics Data System (ADS)

    Rao, Chang-Hui; Zhu, Lei; Rao, Xue-Jun; Zhang, Lan-Qiang; Bao, Hua; Ma, Xue-An; Gu, Nai-Ting; Guan, Chun-Lin; Chen, Dong-Hong; Wang, Cheng; Lin, Jun; Jin, Zen-Yu; Liu, Zhong

    2016-02-01

    The first generation solar adaptive optics (AO) system, which consists of a fine tracking loop with a tip-tilt mirror (TTM) and a correlation tracker, and a high-order correction loop with a 37-element deformable mirror (DM), a correlating Shack-Hartmann (SH) wavefront sensor (WFS) based on the absolute difference algorithm and a real time controller (RTC), has been developed and installed at the 1-m New Vacuum Solar Telescope (NVST) that is part of Fuxian Solar Observatory (FSO). Compared with the 37-element solar AO system developed for the 26-cm Solar Fine Structure Telescope, administered by Yunnan Astronomical Observatories, this AO system has two updates: one is the subaperture arrangement of the WFS changed from square to hexagon; the other is the high speed camera of the WFS and the corresponding real time controller. The WFS can be operated at a frame rate of 2100 Hz and the error correction bandwidth can exceed 100 Hz. After AO correction, the averaged residual image motion and the averaged RMS wavefront error are reduced to 0.06″ and 45 nm, respectively. The results of on-sky testing observations demonstrate better contrast and finer structures of the images taken with AO than those without AO.

  12. Measurements on a shock wave generated by a solar flare

    NASA Astrophysics Data System (ADS)

    Maxwell, A.; Dryer, M.

    1982-11-01

    Shock waves generated by intense solar flares may be driven by a large amount of ejected mass, about 5 x 10 to the 16th g, and the total energy involved may be of the order of 10 to the 32nd erg. The shocks may have initial velocities of the order of 2,000 km/s and, in their exodus through the corona, may be accompanied by fast-moving optical transients, the emission of highly characteristic radio signatures and the acceleration of particles to quasi-relativistic velocities. Here, a review is presented of data on a high-velocity shock generated by a flare on 18 August 1979, 1400 UT, and comments are provided on some previously deduced velocities for the shock. Attention is given to a model, based on current computer programs to account for the overall characteristics of the shock as it propagated through the corona and the interplanetary plasma.

  13. Measurements on a shock wave generated by a solar flare

    NASA Technical Reports Server (NTRS)

    Maxwell, A.; Dryer, M.

    1982-01-01

    Shock waves generated by intense solar flares may be driven by a large amount of ejected mass, about 5 x 10 to the 16th g, and the total energy involved may be of the order of 10 to the 32nd erg. The shocks may have initial velocities of the order of 2,000 km/s and, in their exodus through the corona, may be accompanied by fast-moving optical transients, the emission of highly characteristic radio signatures and the acceleration of particles to quasi-relativistic velocities. Here, a review is presented of data on a high-velocity shock generated by a flare on 18 August 1979, 1400 UT, and comments are provided on some previously deduced velocities for the shock. Attention is given to a model, based on current computer programs to account for the overall characteristics of the shock as it propagated through the corona and the interplanetary plasma.

  14. Alumina Paste Sublimation Suppression Barrier for Thermoelectric Device

    NASA Technical Reports Server (NTRS)

    Paik, Jong-Ah (Inventor); Caillat, Thierry (Inventor)

    2014-01-01

    Alumina as a sublimation suppression barrier for a Zintl thermoelectric material in a thermoelectric power generation device operating at high temperature, e.g. at or above 1000K, is disclosed. The Zintl thermoelectric material may comprise Yb.sub.14MnSb.sub.11. The alumina may be applied as an adhesive paste dried and cured on a substantially oxide free surface of the Zintl thermoelectric material and polished to a final thickness. The sublimation suppression barrier may be finalized by baking out the alumina layer on the Zintl thermoelectric material until it becomes substantially clogged with ytterbia.

  15. Feasibility Investigation for a Solar Power Generation Facility

    NASA Technical Reports Server (NTRS)

    Nathan, Lakshmi

    2010-01-01

    The Energy Policy Act of 2005 states that by fiscal year 2013, at least 7.5% of the energy consumed by the government must be renewable energy. In an effort to help meet this goal, Johnson Space Center (JSC) is considering installing a solar power generation facility. The purpose of this project is to conduct a feasibility investigation for such a facility. Because Kennedy Space Center (KSC) has a solar power generation facility, the first step in this investigation is to learn about KSC's facility and obtain information on how it was constructed. After collecting this information, the following must be determined: the amount of power desired, the size of the facility, potential locations for it, and estimated construction and maintenance costs. Contacts with JSC's energy provider must also be established to determine if a partnership would be agreeable to both parties. Lastly, all of this data must be analyzed to decide whether or not JSC should construct the facility. The results from analyzing the data collected indicate that a 200 kW facility would provide enough energy to meet 1% of JSC's energy demand. This facility would require less than 1 acre of land. In the map below, potential locations are shown in green. The solar power facility is projected to cost $2 M. So far, the information collected indicates that such a facility could be constructed. The next steps in this investigation include contacting JSC's energy provider, CenterPoint Energy, to discuss entering a partnership; developing a life cycle cost analysis to determine payback time; developing more detailed plans; and securing funding.

  16. Oxide Thermoelectrics

    SciTech Connect

    Singh, David J

    2008-01-01

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

  17. Considerations for the next generation of solar telescopes: A systems approach to solar physics

    NASA Astrophysics Data System (ADS)

    Title, A.

    2010-06-01

    The exciting new high resolution images from the one meter Sunrise balloon telescope and the first images from the 1.6 meter Big Bear telescope together with the continuing data from the 1 meter Swedish Solar Observatory demonstrate the promise of the new generation of multimeter solar telescopes. While the promise of the new generation of telescopes is great the technical challenges to build them will require the efforts of a significant fraction of the solar community. In this talk I will emphasize the need for an integrated systems approach to the development of the telescope, its instruments, its software, and its operations and management structures. The experience of several decades of space mission has taught us a great deal about the value of planning mission development from the definition of the primary scientific objectives to the delivery of the data to the science community. Much of these lessons learned, often painfully, should provide guidance to those in developing the new telescope systems.

  18. LIGHTWEIGHT HIGH-POWER THERMOELECTRIC MODULE DEVELOPMENT.

    DTIC Science & Technology

    ELECTRIC POWER PRODUCTION), *GENERATORS), (*THERMOCOUPLES, (*MODULES(ELECTRONICS), THERMOCOUPLES), (*THERMOELECTRICITY, HEAT, ENERGY CONVERSION, SEEBECK EFFECT , BONDED JOINTS, SILICON ALLOYS, GERMANIUM ALLOYS, LEAD ALLOYS, TELLURIUM ALLOYS, METALLOGRAPHY, SPACECRAFT COMPONENTS, MANUFACTURING.

  19. Polymer composites for thermoelectric applications.

    PubMed

    McGrail, Brendan T; Sehirlioglu, Alp; Pentzer, Emily

    2015-02-02

    This review covers recently reported polymer composites that show a thermoelectric (TE) effect and thus have potential application as thermoelectric generators and Peltier coolers. The growing need for CO2-minimizing energy sources and thermal management systems makes the development of new TE materials a key challenge for researchers across many fields, particularly in light of the scarcity or toxicity of traditional inorganic TE materials based on Te and Pb. Recent reports of composites with inorganic and organic additives in conjugated and insulating polymer matrices are covered, as well as the techniques needed to fully characterize their TE properties.

  20. Computational design of materials for solar hydrogen generation

    NASA Astrophysics Data System (ADS)

    Umezawa, Naoto

    Photocatalysis has a great potential for the production of hydrogen from aquerous solution under solar light. In this talk, two different approaches toward the computational materials desing for solar hydrogen generation will be presented. Tin (Sn), which has two major oxidation states, Sn2+ and Sn4+, is abundant on the earth's crust. Recently, visible-light responsive photocatalytc H2 evolution reaction was identified over a mixed valence tin oxide Sn3O4. We have carried out crystal structure prediction for mixed valence tin oxides in different atomic compositions under ambient pressure condition using advanced computational methods based on the evolutionary crystal-structure search and density-functional theory. The predicted novel crystal structures realize the desirable band gaps and band edge positions for H2 evolution under visible light irradiation. It is concluded that multivalent tin oxides have a great potential as an abundant, cheap and environmentally-benign solar-energy conversion photofunctional materials. Transition metal doping is effective for sensitizing SrTiO3 under visible light. We have theoretically investigated the roles of the doped Cr in STO based on hybrid density-functional calculations. Cr atoms are preferably substituting for Ti under any equilibrium growth conditions. The lower oxidation state Cr3+, which is stabilized under an n-type condition of STO, is found to be advantageous for the photocatalytic performance. It is firther predicted that lanthanum is the best codopant for stabilizing the favorable oxidation state, Cr3+. The prediction was validated by our experiments that La and Cr co-doped STO shows the best performance among examined samples. This work was supported by the Japan Science and Technology Agency (JST) Precursory Research for Embryonic Science and Technology (PRESTO) and International Research Fellow program of Japan Society for the Promotion of Science (JSPS) through project P14207.

  1. Generating potassium abundance variations in the Solar Nebula

    NASA Astrophysics Data System (ADS)

    Hubbard, Alexander

    2016-08-01

    An intriguing aspect of chondritic meteorites is that they are complementary: while their separate components have wildly varying abundances, bulk chondrites have nearly solar composition. This implies that the nearly solar reservoirs in which chondrites were born were in turn assembled from sub-reservoirs of differing compositions that birthed the different components. We focus on explaining the potassium abundance variations between chondrules even within a single chondrite, while maintaining the observed CI 41K to 39K ratios. This requires physically separating potassium and chondrules while the temperature is high enough for K to be in the gas phase. We examine several mechanisms which could drive the dust through gas and show that to do so locally would have required long (sub-orbital to many orbits) time scales; with shortest potassium depletion time-scales occurring in a scenario where chondrules formed high above the mid-plane and settled out of the evaporated potassium. While orbital time-scales are at odds with laboratory chondrule cooling rate estimates, any other model for the origin for the potassium abundance variation has to wrestle with the severe logistical difficulty of generating a plethora of correlated reservoirs which varied strongly in their potassium abundances, but not in their potassium isotope ratios.

  2. Assessment of Wind/Solar Co-located Generation in Texas

    SciTech Connect

    Wiese, Steven M

    2009-07-20

    This paper evaluates the opportunity to load co-located wind and solar generation capacity onto a constrained transmission system while engendering only minimal losses. It quantifies the economic and energy opportunities and costs associated with pursuing this strategy in two Texas locations one in west Texas and the other in south Texas. The study builds upon previous work published by the American Solar Energy Society (ASES) which illuminated the potential benefits of negative correlation of wind and solar generation in some locations by quantifying the economic and energy losses which would arise from deployment of solar generation in areas with existing wind generation and constrained transmission capacity. Clean Energy Associates (CEA) obtained and incorporated wind and solar resource data and the Electric Reliability Council of Texas (ERCOT)) load and price data into a model which evaluates varying levels of solar thermal, solar photovoltaic (PV) and wind capacity against an assumed transmission capacity limit at each of the two locations.

  3. On the generation of Alfven waves in the solar photosphere

    NASA Astrophysics Data System (ADS)

    Tsap, Yuriy; Stepanov, Alexander; Kopylova, Yulia

    The influence of collisions between neutrals and ions on the energy flux of Alfven waves in the weakly ionized plasma based on the three-fluid equations is considered. As distinguished from Vranjes et al. (2008) and Soler et al. (2013) it has been shown that amplitudes of Alfven waves that are generated in the solar photosphere do not depend on the ionization ratio and the initial conditions for ions, if the wave frequency is much less that the effective frequency of collisions between ions and neutral atoms. This is explained by the strong coupling due to ion-neutral collisions and the magnetic field freezing-in effect. Alfven waves can be effectively excited in the photosphere of the Sun by the convective motions.

  4. Broad Spectrum Photoelectrochemical Diodes for Solar Hydrogen Generation

    SciTech Connect

    Grimes, Craig A.

    2014-11-26

    Under program auspices we have investigated material chemistries suitable for the solar generation of hydrogen by water photoelectrolysis. We have built upon, and extended, our knowledge base on the synthesis and application of TiO2 nanotube arrays, a material architecture that appears ideal for water photoelectrolysis. To date we have optimized, refined, and greatly extended synthesis techniques suitable for achieving highly ordered TiO2 nanotube arrays of given length, wall thickness, pore diameter, and tube-to-tube spacing for use in water photoelectrolysis. We have built upon this knowledge based to achieve visible light responsive, photocorrosion stable n-type and p-type ternary oxide nanotube arrays for use in photoelectrochemical diodes.

  5. Solar salt pond potential site survey for electrical power generation

    NASA Technical Reports Server (NTRS)

    Hurick, M. G.

    1982-01-01

    A solar salt gradient pond acts as a passive heat sink or thermal battery in which energy can be recovered through the conversion of thermal energy into electrical energy. Here, a condensation of a larger report that focused on the identification of potential salt gradient pond sites in the United States using in-situ resources is presented. It is shown that there are at least 24 states that lie in a primary or secondary potential site category. Fourteen states are assigned as primary states and ten are assigned as secondary. The division is subjectively based on the severity of winter weather. The most promising states are those that lie in the southern half of the country. When the primary and secondary category states are combined with the other states that may be able to support a pond, a total of 38 states exhibit the possibility of supporting power generation sites of various size.

  6. Performance tests and efficiency analysis of Solar Invictus 53S - A parabolic dish solar collector for direct steam generation

    NASA Astrophysics Data System (ADS)

    Jamil, Umer; Ali, Wajahat

    2016-05-01

    This paper presents the results of performance tests conducted on Solar Invictus 53S `system'; an economically effective solar steam generation solution designed and developed by ZED Solar Ltd. The system consists of a dual axis tracking parabolic solar dish and bespoke cavity type receiver, which works as a Once Through Solar Steam Generator `OTSSG' mounted at the focal point of the dish. The overall performance and efficiency of the system depends primarily on the optical efficiency of the solar dish and thermal efficiency of the OTSSG. Optical testing performed include `on sun' tests using CCD camera images and `burn plate' testing to evaluate the sunspot for size and quality. The intercept factor was calculated using a colour look-back method to determine the percentage of solar rays focused into the receiver. Solar dish tracking stability tests were carried out at different times of day to account for varying dish elevation angles and positions, movement of the sunspot centroid was recorded and logged using a CCD camera. Finally the overall performance and net solar to steam efficiency of the system was calculated by experimentally measuring the output steam parameters at varying Direct Normal Insolation (DNI) levels at ZED Solar's test facility in Lahore, Pakistan. Thermal losses from OTSSG were calculated using the known optical efficiency and measured changes in output steam enthalpy.

  7. Analyzing the Impact of Solar Power on Multi-Hourly Thermal Generator Ramping

    SciTech Connect

    Rosenkranz, Joshua-Benedict; Brancucci Martinez-Anido, Carlo; Hodge, Bri-Mathias

    2016-04-08

    Solar power generation, unlike conventional forms of electricity generation, has higher variability and uncertainty in its output because solar plant output is strongly impacted by weather. As the penetration rate of solar capacity increases, grid operators are increasingly concerned about accommodating the increased variability and uncertainty that solar power provides. This paper illustrates the impacts of increasing solar power penetration on the ramping of conventional electricity generators by simulating the operation of the Independent System Operator -- New England power system. A production cost model was used to simulate the power system under five different scenarios, one without solar power and four with increasing solar power penetrations up to 18%, in terms of annual energy. The impact of solar power is analyzed on six different temporal intervals, including hourly and multi-hourly (2- to 6-hour) ramping. The results show how the integration of solar power increases the 1- to 6-hour ramping events of the net load (electric load minus solar power). The study also analyzes the impact of solar power on the distribution of multi-hourly ramping events of fossil-fueled generators and shows increasing 1- to 6-hour ramping events for all different generators. Generators with higher ramp rates such as gas and oil turbine and internal combustion engine generators increased their ramping events by 200% to 280%. For other generator types--including gas combined-cycle generators, coal steam turbine generators, and gas and oil steam turbine generators--more and higher ramping events occurred as well for higher solar power penetration levels.

  8. Evaluation of solar thermal storage for base load electricity generation

    NASA Astrophysics Data System (ADS)

    Adinberg, R.

    2012-10-01

    In order to stabilize solar electric power production during the day and prolong the daily operating cycle for several hours in the nighttime, solar thermal power plants have the options of using either or both solar thermal storage and fossil fuel hybridization. The share of solar energy in the annual electricity production capacity of hybrid solar-fossil power plants without energy storage is only about 20%. As it follows from the computer simulations performed for base load electricity demand, a solar annual capacity as high as 70% can be attained by use of a reasonably large thermal storage capacity of 22 full load operating hours. In this study, the overall power system performance is analyzed with emphasis on energy storage characteristics promoting a high level of sustainability for solar termal electricity production. The basic system parameters, including thermal storage capacity, solar collector size, and annual average daily discharge time, are presented and discussed.

  9. Bulk dimensional nanocomposites for thermoelectric applications

    DOEpatents

    Nolas, George S

    2014-06-24

    Thermoelectric elements may be used for heat sensors, heat pumps, and thermoelectric generators. A quantum-dot or nano-scale grain size polycrystalline material the effects of size-quantization are present inside the nanocrystals. A thermoelectric element composed of densified Groups IV-VI material, such as calcogenide-based materials are doped with metal or chalcogenide to form interference barriers form along grains. The dopant used is either silver or sodium. These chalcogenide materials form nanoparticles of highly crystal grains, and may specifically be between 1- and 100 nm. The compound is densified by spark plasma sintering.

  10. Thermoelectric materials and devices

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  11. A review on the fabrication of polymer-based thermoelectric materials and fabrication methods.

    PubMed

    Kamarudin, Muhammad Akmal; Sahamir, Shahrir Razey; Datta, Robi Shankar; Long, Bui Duc; Mohd Sabri, Mohd Faizul; Mohd Said, Suhana

    2013-11-12

    Thermoelectricity, by converting heat energy directly into useable electricity, offers a promising technology to convert heat from solar energy and to recover waste heat from industrial sectors and automobile exhausts. In recent years, most of the efforts have been done on improving the thermoelectric efficiency using different approaches, that is, nanostructuring, doping, molecular rattling, and nanocomposite formation. The applications of thermoelectric polymers at low temperatures, especially conducting polymers, have shown various advantages such as easy and low cost of fabrication, light weight, and flexibility. In this review, we will focus on exploring new types of polymers and the effects of different structures, concentrations, and molecular weight on thermoelectric properties. Various strategies to improve the performance of thermoelectric materials will be discussed. In addition, a discussion on the fabrication of thermoelectric devices, especially suited to polymers, will also be given. Finally, we provide the challenge and the future of thermoelectric polymers, especially thermoelectric hybrid model.

  12. A Review on the Fabrication of Polymer-Based Thermoelectric Materials and Fabrication Methods

    PubMed Central

    Kamarudin, Muhammad Akmal; Sahamir, Shahrir Razey; Datta, Robi Shankar; Long, Bui Duc; Mohd Sabri, Mohd Faizul; Mohd Said, Suhana

    2013-01-01

    Thermoelectricity, by converting heat energy directly into useable electricity, offers a promising technology to convert heat from solar energy and to recover waste heat from industrial sectors and automobile exhausts. In recent years, most of the efforts have been done on improving the thermoelectric efficiency using different approaches, that is, nanostructuring, doping, molecular rattling, and nanocomposite formation. The applications of thermoelectric polymers at low temperatures, especially conducting polymers, have shown various advantages such as easy and low cost of fabrication, light weight, and flexibility. In this review, we will focus on exploring new types of polymers and the effects of different structures, concentrations, and molecular weight on thermoelectric properties. Various strategies to improve the performance of thermoelectric materials will be discussed. In addition, a discussion on the fabrication of thermoelectric devices, especially suited to polymers, will also be given. Finally, we provide the challenge and the future of thermoelectric polymers, especially thermoelectric hybrid model. PMID:24324378

  13. High energy neutron and gamma-radiation generated during the solar flares

    NASA Technical Reports Server (NTRS)

    Kocharov, G. E.; Mandzhavidze, N. Z.

    1985-01-01

    The problem of high energy neutrons and gamma rays generation in the solar conditions is considered. It is shown that due to a peculiarity of generation and propagation of neutrons corresponding solar flares should be localized at high helio-longitudes.

  14. Radioisotope Power System Delivery, Ground Support and Nuclear Safety Implementation: Use of the Multi-Mission Radioisotope Thermoelectric Generator for the NASA's Mars Science Laboratory

    SciTech Connect

    S.G. Johnson; K.L. Lively; C.C. Dwight

    2014-07-01

    Radioisotope power systems have been used for over 50 years to enable missions in remote or hostile environments. They are a convenient means of supplying a few milliwatts up to a few hundred watts of useable, long-term electrical power. With regard to use of a radioisotope power system, the transportation, ground support and implementation of nuclear safety protocols in the field is a complex process that requires clear identification of needed technical and regulatory requirements. The appropriate care must be taken to provide high quality treatment of the item to be moved so it arrives in a condition to fulfill its missions in space. Similarly it must be transported and managed in a manner compliant with requirements for shipment and handling of special nuclear material. This presentation describes transportation, ground support operations and implementation of nuclear safety and security protocols for a radioisotope power system using recent experience involving the Multi-Mission Radioisotope Thermoelectric Generator for National Aeronautics and Space Administration’s Mars Science Laboratory, which launched in November of 2011.

  15. Thermoelectric Study of Copper Selenide

    NASA Astrophysics Data System (ADS)

    Yao, Mengliang; Liu, Weishu; Ren, Zhifeng; Opeil, Cyril

    2014-03-01

    Nanostructuring has been shown to be an effective approach in reducing lattice thermal conductivity and improving the figure of merit of thermoelectric materials. Copper selenide is a layered structure material, which has a low thermal conductivity and p-type Seebeck coefficient at low temperatures. We have evaluated several hot-pressed, nanostructured copper selenide samples with different dopants for their thermoelectric properties. The phenomenon of the charge-density wave observed in the nanocomposite, resistivity, Seebeck, thermal conductivity and carrier mobility will be discussed. Funding for this research was provided by the Solid State Solar - Thermal Energy Conversion Center (S3TEC), an Energy Frontier Research Center sponsored by the DOE, Office of Basic Energy Science, Award No. DE-SC0001299/ DE-FG02-09ER46577.

  16. Robust and Low-cost Flame-Treated Wood for High-Performance Solar Steam Generation.

    PubMed

    Xue, Guobin; Liu, Kang; Chen, Qian; Yang, Peihua; Li, Jia; Ding, Tianpeng; Duan, Jiangjiang; Qi, Bei; Zhou, Jun

    2017-04-12

    Solar-enabled steam generation has attracted increasing interests in recent years for its potential applications in power generation, desalination and wastewater treatment etc. Latest researches have reported many strategies to promote the efficiency by employing absorbers based on carbon materials or plasmonic metal nanoparticles with well-defined pores. In this work, we report that natural wood can be utilized as an ideal solar absorber after a simple flame treatment. With ultra-high solar absorbance (~99%), low thermal conductivity (0.33 W m-1 K-1), good hydrophilicity, the flame-treated wood can localize the solar-heating at the evaporation surface and enable a solar thermal efficiency of ~72% under a solar intensity of 1 kW m-2, which demonstrating a renewable, scalable, low-cost and robust material for solar steam applications.

  17. Novel Transition Metal Compounds with Promising Thermoelectric Properties

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    Progress in the search for new high temperature thermoelectric materials at the Jet Propulsion Laboratory is reviewed. Novel transition metal compounds were selected as potential new high performance thermoelectric materials and criteria of selection are presented and discussed. Samples of these new compounds were prepared at JPL by a variety of techniques. Encouraging experimental results obtained on several of these compounds are reported and show that they have the potential to be the next generation of thermoelectric materials.

  18. 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.

  19. Evaluation of glare at the Ivanpah Solar Electric Generating System

    DOE PAGES

    Ho, C. K.; Sims, C. A.; Christian, J. M.

    2015-06-05

    The Ivanpah Solar Electric Generating System (ISEGS), located on I-15 about 40 miles (60 km) south of Las Vegas, NV, consists of three power towers 459 ft (140 m) tall and over 170,000 reflective heliostats with a rated capacity of 390 MW. In addition, reports of glare from the plant have been submitted by pilots and air traffic controllers and recorded by the Aviation Safety Reporting System and the California Energy Commission since 2013. Aerial and ground-based surveys of the glare were conducted in April, 2014, to identify the cause and to quantify the irradiance and potential ocular impacts ofmore » the glare. Results showed that the intense glare viewed from the airspace above ISEGS was caused by heliostats in standby mode that were aimed to the side of the receiver. Evaluation of the glare showed that the retinal irradiance and subtended source angle of the glare from the heliostats in standby were sufficient to cause significant ocular impact (potential for after-image) up to a distance of ~6 miles (10 km), but the values were below the threshold for permanent eye damage. Glare from the receivers had a low potential for after-image at all ground-based monitoring locations outside of the site boundaries. A Letter to Airmen has been issued by the Federal Aviation Administration to notify pilots of the potential glare hazards. Additional measures to mitigate the potential impacts of glare from ISGES are also presented and discussed.« less

  20. Evaluation of Glare at the Ivanpah Solar Electric Generating System

    SciTech Connect

    Ho, Clifford K.; Sims, Cianan; Christian, Joshua Mark

    2014-07-01

    The Ivanpah Solar Electric Generating System (ISEGS), located on I - 15 about 40 miles (60 km) south of Las Vegas, NV, consists of three power towers 459 ft (140 m) tall and over 170,000 reflective heliostats with a rated capacity of 390 MW. Reports of glare from the plant have been submitted by pilots and air traffic controllers and recorded by the Aviation Safety Reporting System and the California Energy Commission since 2013. Aerial and ground - based surveys of the glare were conducted in April, 2014, to identify the cause and to quantify the irradiance and potential ocular impact s of the glare . Results showed that the intense glare viewed from the airspace above ISEGS was caused by he liostats in standby mode that were aimed to the side of the receiver. Evaluation of the glare showed that the retinal irradiance and subtended source angle of the glare from the heliostats in standby were sufficient to cause significant ocular impact (pot ential for after - image) up to a distance of %7E6 miles (10 km), but the values were below the threshold for permanent eye damage . Glare from the receivers had a low potential for after - image at all ground - based monitoring locations outside of the site bound aries. A Letter to Airmen has been issued by the Federal Aviation Administration to notify pilots of the potential glare hazards. Additional measures to mitigate the potential impacts of glare from ISGES are also presented and discussed. This page intentionally left blank