SEARCH · Search NASA

Results for “Electrically heated Thermoelectric Generator”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4

All sources NASA NTRS DOE OSTI

NASA NTRS1988

Direct conversion technology

The overall objective of the Direct Conversion Technology task is to develop an experimentally verified technology base for promising direct thermal-to-electric energy conversion systems that have potential application for energy conservation in the end-use sectors. This report contains progress of research on the Alkali Metal Thermal-to-Electric Converter (AMTEC), and on the Two-Phase Liquid-Metal MHD Electrical Generator (LMMHD) for the period January 1988 through December 1988. Research on these concepts was initiated during October 1987. In addition, status reviews and assessments are presented for thermomagnetic converter concepts and for thermoelastic converters (Nitinol heat engines). Reports prepared on previous occasions contain discussions on the following other direct conversion concepts: thermoelectric, pyroelectric, thermionic thermophotovoltaic and thermoacoustic; and also, more complete discussions of AMTEC and LMMHD systems. A tabulated summary of the various systems which have been reviewed thus far has been prepared. Some of the important technical research needs are listed and a schematic of each system is shown.

Massier, P. F.↗

NASA NTRS2008

Simulating the Gradually Deteriorating Performance of an RTG

Degra (now in version 3) is a computer program that simulates the performance of a radioisotope thermoelectric generator (RTG) over its lifetime. Degra is provided with a graphical user interface that is used to edit input parameters that describe the initial state of the RTG and the time-varying loads and environment to which it will be exposed. Performance is computed by modeling the flows of heat from the radioactive source and through the thermocouples, also allowing for losses, to determine the temperature drop across the thermocouples. This temperature drop is used to determine the open-circuit voltage, electrical resistance, and thermal conductance of the thermocouples. Output power can then be computed by relating the open-circuit voltage and the electrical resistance of the thermocouples to a specified time-varying load voltage. Degra accounts for the gradual deterioration of performance attributable primarily to decay of the radioactive source and secondarily to gradual deterioration of the thermoelectric material. To provide guidance to an RTG designer, given a minimum of input, Degra computes the dimensions, masses, and thermal conductances of important internal structures as well as the overall external dimensions and total mass.

Wood, Eric G.↗

NASA NTRS2014

Non-Cooled Power System for Venus Lander

The Planetary Science Decadal Survey of 2013-2022 stated that the exploration of Venus is of significant interest. Studying the seismic activity of the planet is of particular importance because the findings can be compared to the seismic activity of Earth. Further, the geological and atmospheric properties of Venus will shed light into the past and future of Earth. This paper presents a radioisotope power system (RPS) design for a small low-power Venus lander. The feasibility of the new power system is then compared to that of primary batteries. A requirement for the power source system is to avoid moving parts in order to not interfere with the primary objective of the mission - to collect data about the seismic activity of Venus using a seismometer. The target mission duration of the lander is 117 days, a significant leap from Venera 13, the longest-lived lander on the surface of Venus, which survived for 2 hours. One major assumption for this mission design is that the power source system will not provide cooling to the other components of the lander. This assumption is based on high-temperature electronics technology that will enable the electronics and components of the lander to operate at Venus surface temperature. For the proposed RPS, a customized General Purpose Heat Source Radioisotope Thermoelectric Generator (GPHSRTG) is designed and analyzed. The GPHS-RTG is chosen primarily because it has no moving parts and it is capable of operating for long duration missions on the order of years. This power system is modeled as a spherical structure for a fundamental thermal analysis. The total mass and electrical output of the system are calculated to be 24 kilograms and 26 Watts, respectively. An alternative design for a battery-based power system uses Sodium Sulfur batteries. To deliver a similar electrical output for 117 days, the battery mass is calculated to be 234 kilograms. Reducing mission duration or power required will reduce the required battery mass. Finally, the advantages and disadvantages of both power systems with regard to science return, risk, and cost are briefly compared. The design of the radioisotope power system is considerably riskier because it is novel and would require additional years of further refinement, manufacturing, safety analysis, and testing that the primary batteries do not need. However, the lifetime of the radioisotope power system makes its science return more promising.

planetary↗

NASA NTRS1992

Solar probe power systems concepts

Some of the design options under consideration for providing on-board electric power for the Solar Probe Mission are discussed. Five spacecraft configurations were evaluated with slightly different power demands and volumetric constraints on the power system. This resulted in three different baseline power system designs to satisfy the five spacecraft configurations. These three current baseline power system designs use modified general-purpose heat source (GPHS) radioisotope thermoelectric generators (RTGs) similar to those launched on the Galileo and Ulysses spacecraft. The modular RTG currently under development and testing is a potential advanced alternative to the current baseline GPHS-RTG technology design.

Nesmith, Bill J.↗

NASA NTRS1989

Preliminary assessment of rover power systems for the Mars Rover Sample Return Mission

Four isotope power system concepts were presented and compared on a common basis for application to on-board electrical prime power for an autonomous planetary rover vehicle. A representative design point corresponding to the Mars Rover Sample Return (MRSR) preliminary mission requirements (500 W) was selected for comparison purposes. All systems concepts utilize the General Purpose Heat Source (GPHS) isotope heat source developed by DOE. Two of the concepts employ thermoelectric (TE) conversion: one using the GPHS Radioisotope Thermoelectric Generator (RTG) used as a reference case, the other using an advanced RTG with improved thermoelectric materials. The other two concepts employed are dynamic isotope power systems (DIPS): one using a closed Brayton cycle (CBC) turboalternator, and the other using a free piston Stirling cycle engine/linear alternator (FPSE) with integrated heat source/heater head. Near term technology levels have been assumed for concept characterization using component technology figure-of-merit values taken from the published literature. For example, the CBC characterization draws from the historical test database accumulated from space Brayton cycle subsystems and components from the NASA B engine through the mini-Brayton rotating unit. TE system performance is estimated from Voyager/multihundred Watt (MHW)-RTG flight experience through Mod-RTG performance estimates considering recent advances in TE materials under the DOD/DOE/NASA SP-100 and NASA Committee on Scientific and Technological Information programs. The Stirling DIPS system is characterized from scaled-down Space Power Demonstrator Engine (SPDE) data using the GPHS directly incorporated into the heater head. The characterization/comparison results presented here differ from previous comparison of isotope power (made for Low Earth Orbit (LEO) applications) because of the elevated background temperature on the Martian surface compared to LEO, and the higher sensitivity of dynamic systems to elevated sink temperature. The mass advantage of dynamic systems is significantly reduced for this application due to Mars' elevated background temperature.

Bents, David J.↗

NASA NTRS1989

Preliminary assessment of rover power systems for the Mars Rover Sample Return Mission

Four isotope power system concepts were presented and compared on a common basis for application to on-board electrical prime power for an autonomous planetary rover vehicle. A representative design point corresponding to the Mars Rover Sample Return (MRSR) preliminary mission requirements (500 W) was selected for comparison purposes. All systems concepts utilize the General Purpose Heat Source (GPHS) isotope heat source developed by DOE. Two of the concepts employ thermoelectric (TE) conversion: one using the GPHS Radioisotope Thermoelectric Generator (RTG) used as a reference case, the other using an advanced RTG with improved thermoelectric materials. The other two concepts employed are dynamic isotope power systems (DIPS): one using a closed Brayton cycle (CBC) turboalternator, and the other using a free piston Stirling cycle engine/linear alternator (FPSE) with integrated heat source/heater head. Near-term technology levels have been assumed for concept characterization using component technology figure-of-merit values taken from the published literature. For example, the CBC characterization draws from the historical test database accumulated from space Brayton cycle subsystems and components from the NASA B engine through the mini-Brayton rotating unit. TE system performance is estimated from Voyager/multihundred Watt (MHW)-RTG flight experience through Mod-RTG performance estimates considering recent advances in TE materials under the DOD/DOE/NASA SP-100 and NASA Committee on Scientific and Technological Information programs. The Stirling DIPS system is characterized from scaled-down Space Power Demonstrator Engine (SPDE) data using the GPHS directly incorporated into the heater head. The characterization/comparison results presented here differ from previous comparison of isotope power (made for LEO applications) because of the elevated background temperature on the Martian surface compared to LEO, and the higher sensitivity of dynamic systems to elevated s

Bents, D. J.↗

NASA NTRS2007

Ice-Penetrating Robot for Scientific Exploration

The cryo-hydro integrated robotic penetrator system (CHIRPS) is a partially developed instrumentation system that includes a probe designed to deeply penetrate the European ice sheet in a search for signs of life. The CHIRPS could also be used on Earth for similar exploration of the polar ice caps especially at Lake Vostok in Antarctica. The CHIRPS probe advances downward by a combination of simple melting of ice (typically for upper, non-compacted layers of an ice sheet) or by a combination of melting of ice and pumping of meltwater (typically, for deeper, compacted layers). The heat and electric power for melting, pumping, and operating all of the onboard instrumentation and electronic circuitry are supplied by radioisotope power sources (RPSs) and thermoelectric converters energized by the RPSs. The instrumentation and electronic circuitry includes miniature guidance and control sensors and an advanced autonomous control system that has fault-management capabilities. The CHIRPS probe is about 1 m long and 15 cm in diameter. The RPSs generate a total thermal power of 1.8 kW. Initially, as this power melts the surrounding ice, a meltwater jacket about 1 mm thick forms around the probe. The center of gravity of the probe is well forward (down), so that the probe is vertically stabilized like a pendulum. Heat is circulated to the nose by means of miniature pumps and heat pipes. The probe melts ice to advance in a step-wise manner: Heat is applied to the nose to open up a melt void, then heat is applied to the side to allow the probe to slip down into the melt void. The melt void behind the probe is allowed to re-freeze. Four quadrant heaters on the nose and another four quadrant heaters on the rear (upper) surface of the probe are individually controllable for steering: Turning on two adjacent nose heaters on the nose and two adjacent heaters on the opposite side at the rear causes melt voids to form on opposing sides, such that the probe descends at an angle from vertical. This steering capability can be used to avoid debris trapped in the ice or to maneuver closer to a trapped object of scientific interest.

Zimmerman, Wayne↗

NASA NTRS2001

Stirling Radioisotope Power System as an Alternative for NASAs Deep Space Missions

The NASA Glenn Research Center (GRC) and the Department of Energy (DOE) are developing a free-piston Stirling convertor for a Stirling Radioisotope Power System (SRPS) to provide on-board electric power for future NASA deep space missions. The SRPS currently being developed provides about 100 watts and reduces the amount of radioisotope fuel by a factor of four over conventional Radioisotope Thermoelectric Generators (RTG). The present SRPS design has a specific power of approximately 4 W/kg which is comparable to an RTG. GRC estimates for advanced versions of the SRPS with improved heat source integration, lightweight Stirling convertors, composite radiators, and chip-packaged controllers improves the specific mass to about 8 W/kg. Additional information is contained in the original extended abstract.

Shaltens, R. K.↗

NASA NTRS2012

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

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

Prasad, Narasimha S.↗

NASA NTRS2005

An Overview and Status of NASA's Radioisotope Power Conversion Technology NRA

NASA's Advanced Radioisotope Power Systems (RPS) development program is developing next generation radioisotope power conversion technologies that will enable future missions that have requirements that can not be met by either photovoltaic systems or by current Radioisotope Power System (RPS) technology. The Advanced Power Conversion Research and Technology project of the Advanced RPS development program is funding research and technology activities through the NASA Research Announcement (NRA) 02- OSS-01, "Research Opportunities in Space Science 2002" entitled "Radioisotope Power Conversion Technology" (RPCT), 13 August 2002. The objective of the RPCT NRA is to advance the development of radioisotope power conversion technologies to provide significant improvements over the state-of-practice General Purpose Heat Source/Radioisotope Thermoelectric Generator by providing significantly higher efficiency to reduce the number of radioisotope fuel modules, and increase specific power (watts/kilogram). Other Advanced RPS goals include safety, long-life, reliability, scalability, multi-mission capability, resistance to radiation, and minimal interference with the scientific payload. These advances would enable a factor of 2 to 4 decrease in the amount of fuel required to generate electrical power. The RPCT NRA selected advanced RPS power conversion technology research and development proposals in the following three areas: innovative RPS power conversion research, RPS power conversion technology development in a nominal 100We scale; and, milliwatt/multi-watt RPS (mWRPS) power conversion research. Ten RPCT NRA contracts were awarded in 2003 in the areas of Brayton, Stirling, thermoelectric (TE), and thermophotovoltaic (TPV) power conversion technologies. This paper will provide an overview of the RPCT NRA, and a brief summary of accomplishments over the first 18 months but focusing on advancements made over the last 6 months.

Anderson, David J.↗

NASA NTRSDate not supplied

A Comparison of Radioisotope and Solar Array/Battery Power Systems in the Solar System

Radioisotope Power Systems (RPS) are an invaluable resource for the exploration of our solar system. Providing both heat and electricity, spacecraft using RPS can operate where its impractical to use solar array and/or battery systems because of either limited solar illumination or mission durations which make a standalone battery impractical. This paper highlights the performance advantages which may come from using a RPS compared with a solar array/battery system. Included in this paper is an overview of the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), the Next-Generation RTG (NGRTG) and Dynamic Radioisotope System (DRPS). State-the-Art (SOA) performance of solar arrays and batteries is discussed. Finally, a comparison of both solar cell/battery systems compare with RPS are made at a variety of locations, both orbital and on the surface of some planets and their moons within our solar system.

Paul C Schmitz↗

NASA NTRSDate not supplied

A Comparison of Radioisotope and Solar Array/Battery Power Systems in the Solar System

Paul C Schmitz↗

NASA NTRSDate not supplied

A Comparison of Radioisotope and Solar Array/Battery Power Systems in the Solar System

Paul Schmitz↗

NASA NTRS2021

Thermoelectric System Economics - The Apex: New Paradigms in Manufacturing and Interface Performance Relationships Driving System Cost Optimizations

Thermoelectric energy recovery systems require cost-optimized designs with high thermal and thermoelectric (TE) performance to surmount common commercialization barriers controlling the acceptance of thermoelectric generator (TEG) systems. Recent work has addressed this requirement with new analytic tools and paradigms that allow integrated TEG cost-performance analysis and optimization. New work herein has identified the existence of optimized TE element design (i.e., TE element length) for minimizing TEG cost and provides design guidelines associated with critical thermal and electrical contact resistance effects and TE manufacturing sensitivities. Once optimum hot-side heat flux criteria are satisfied, this work highlights the tradeoffs between interface resistance effects and manufacturing cost effects in determining optimum-cost TE element lengths, and then quantifies the increase in optimum-cost TE lengths as manufacturing costs become more sensitive to TE element lengths. Optimized TE element design criteria and key non-dimensional design parameters (i.e., [𝐶′′′LTE/𝐶′′], [TE/con], [con/(TE,aveLTE)]) driving the design are presented and explained showing the interdependencies between manufacturing cost parameters and thermal and electrical interface impacts on integrated TE cost-performance analysis and design. Comprehensive TEG system cost-performance relationships clearly demonstrate the two parameters that most greatly impact the TEG system cost are heat exchanger costs ($/(W/K)) and TE hot side heat flux. Reducing heat exhanger cost from $1/(W/K) to $0.5/(W/K) can decrease TEG system cost by $2/W to $4/W depending on TE hot side heat fluxes from 4-10 W/cm2. The impact of TE hot side heat flux on TEG system cost is larger; reducing TE system cost by factors of 2-4 as TE hot side heat flux increases from 4 W/cm2 to high levels around 18 W/cm2. The levels of thermal contact resistance and electrical contact resistance required to even approach the critical TEG system cost level of $1/W are characterized by con = 1.0 x 10-10 -m2 and r = 0.1, respectively. This not only lowers TEG costs, but it also makes the TEG system costs less sensitive to TE manufacturing dependences on TE element length. New design paradigms and relationships create holistic, integrated TE performance-cost models that enhance understanding of crucial interrelationships between component costs, TE design parameters and material properties, heat exchanger design parameters, interfacial heat flux, and now thermal and electrical interface effects in minimizing TEG system costs.

Hendricks, Terry J.↗

NASA NTRS2005

NASA Radioisotope Power Conversion Technology NRA Overview

The focus of the National Aeronautics and Space Administration s (NASA) Radioisotope Power Systems (RPS) Development program is aimed at developing nuclear power and technologies that would improve the effectiveness of space science missions. The Radioisotope Power Conversion Technology (RPCT) NASA Research Announcement (NRA) is an important mechanism through which research and technology activities are supported in the Advanced Power Conversion Research and Technology project of the Advanced Radioisotope Power Systems Development program. The purpose of the RPCT NRA is to advance the development of radioisotope power conversion technologies to provide higher efficiencies and specific powers than existing systems. These advances would enable a factor of 2 to 4 decrease in the amount of fuel and a reduction of waste heat required to generate electrical power, and thus could result in more cost effective science missions for NASA. The RPCT NRA selected advanced RPS power conversion technology research and development proposals in the following three areas: innovative RPS power conversion research, RPS power conversion technology development in a nominal 100We scale; and, milliwatt/multi-watt RPS (mWRPS) power conversion research. Ten RPCT NRA contracts were awarded in 2003 in the areas of Brayton, Stirling, thermoelectric (TE), and thermophotovoltaic (TPV) power conversion technologies. This paper will provide an overview of the RPCT NRA, a summary of the power conversion technologies approaches being pursued, and a brief digest of first year accomplishments.

Anderson, David J.↗

NASA NTRS2011

A Small Fission Power System for NASA Planetary Science Missions

In March 2010, the Decadal Survey Giant Planets Panel (GPP) requested a short-turnaround study to evaluate the feasibility of a small Fission Power System (FPS) for future unspecified National Aeronautics and Space Administration (NASA) science missions. FPS technology was considered a potential option for power levels that might not be achievable with radioisotope power systems. A study plan was generated and a joint NASA and Department of Energy (DOE) study team was formed. The team developed a set of notional requirements that included 1-kW electrical output, 15-year design life, and 2020 launch availability. After completing a short round of concept screening studies, the team selected a single concept for concentrated study and analysis. The selected concept is a solid block uranium-molybdenum reactor core with heat pipe cooling and distributed thermoelectric power converters directly coupled to aluminum radiator fins. This paper presents the preliminary configuration, mass summary, and proposed development program.

Mason, Lee↗

NASA NTRS2005

NASA Radioisotope Power Conversion Technology NRA Overview

The focus of the National Aeronautics and Space Administration's (NASA) Radioisotope Power Systems (RPS) Development program is aimed at developing nuclear power and technologies that would improve the effectiveness of space science missions. The Radioisotope Power Conversion Technology (RPCT) NASA Research Announcement (NRA) is an important mechanism through which research and technology activities are supported in the Advanced Power Conversion Research and Technology project of the Advanced Radioisotope Power Systems Development program. The purpose of the RPCT NRA is to advance the development of radioisotope power conversion technologies to provide higher efficiencies and specific powers than existing systems. These advances would enable a factor of two to four decrease in the amount of fuel and a reduction of waste heat required to generate electrical power, and thus could result in more cost effective science missions for NASA. The RPCT NRA selected advanced RPS power conversion technology research and development proposals in the following three areas: innovative RPS power conversion research, RPS power conversion technology development in a nominal 100 W(sub e) scale; and, milliwatt/multi-watt RPS (mWRPS) power conversion research. Ten RPCT NRA contracts were awarded in 2003 in the areas of Brayton, Stirling, thermoelectric (TE), and thermophotovoltaic (TPV) power conversion technologies. This paper will provide an overview of the RPCT NRA, a summary of the power conversion technologies approaches being pursued, and a brief digest of first year accomplishments.

Anderson, David J.↗

NASA NTRS1987

Speculations on future opportunities to evolve Brayton powerplants aboard the space station

The Space Station provides a unique, low risk environment in which to evolve new capabilities. In this way, the Space Station will grow in capacity, in its range of capabilities, and its economy of operation as a laboratory and as a center for space operations. The Brayton cycle using a mixture of He and Xe as its working fluid is examined herein. Using a Brayton powerplant to supply the station's increasing demands for both electric power and heat has the potential to gradually evolve higher and higher performance by exploiting already evolved materials (Ta alloy and molten-Li heat storage), its peak cycle temperature rising ultimately to 1500 K. Adapting the station to exploit long tethers (200 to 300 km) could yield increases in payloads to LEO, to GEO, and to distant destinations in the solar system. Such tethering of the Space Station would not only require additional power for electric propulsion but also would so increase nuclear safety that nuclear powerplants might provide this power. From an 8000 kWt SP-100 reactor, thermoelectric power generation could produce 300 kWe, or adapted solar-Brayton cycle, 2400 to 2800 kWe.

English, Robert E.↗