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Sample records for 110-watt stirling radioisotope

  1. Final Results for the GRC Supporting Technology Development Project for the 110-Watt Stirling Radioisotope Generator (SRG110)

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.

    2007-01-01

    From 1999-2006, the NASA Glenn Research Center (GRC) supported the development of a high-efficiency, nominal 110-We Stirling Radioisotope Generator (SRG110) for potential use on NASA missions, including deep space missions, Mars rovers, and lunar applications. Lockheed Martin (LM) was the system integrator for the SRG110, under contract to the Department of Energy (DOE). Infinia Corporation (formerly Stirling Technology Company) developed the Stirling convertor, first as a contractor to DOE and then under subcontract to LM. The SRG110 development has been redirected, and recent program changes have been made to significantly increase the specific power of the generator. System development of an Advanced Stirling Radioisotope Generator (ASRG) has now begun, using a lightweight, advanced convertor from Sunpower, Inc. This paper summarizes the results of the supporting technology effort that GRC completed for the SRG110. GRC tasks included convertor extended-duration testing in air and thermal vacuum environments, heater head life assessment, materials studies, permanent magnet aging characterization, linear alternator evaluations, structural dynamics testing, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) characterization, organic materials evaluations, reliability studies, and development of an end-to-end system dynamic model. Related efforts are now continuing in many of these areas to support ASRG development.

  2. Final Results for the GRC Supporting Technology Development Project for the 110-Watt Stirling Radioisotope Generator (SRG110)

    NASA Astrophysics Data System (ADS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.

    2007-01-01

    From 1999-2006, the NASA Glenn Research Center (GRC) supported the development of a high-efficiency, nominal 110-We Stirling Radioisotope Generator (SRG110) for potential use on NASA missions, including deep space missions. Mars rovers, and lunar applications. Lockheed Martin (LM) was the system integrator for the SRG110, under contact to the Department of Energy (DOE). Infinia Corporation (formerly Stirling Technology Company) developed the Stirling converter. First as a contractor to DOE and then under subcontract to LM. The SRG110 development has been redirected, and recent program changes have been made to significantly increase the specific power of the generator. System development of an Advanced Stirling Radioisotope Generator (ASRG) has now begun, using a lightweight, advanced converter from Sunpower, Inc. This paper summarizes the results of the supporting technology effort that GRC completed for the SRG110. GRC tasks included converter extended-duration testing in air and thermal vacuum environments, heater head life assessment, materials studies, permanent magnet aging characterization, linear alternator evaluations, structural dynamics testing, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) characterization, organic materials evaluations, reliability studies, and development of an end-to-end system dynamic model. Related efforts are now continuing in many of these areas to support ASRG development.

  3. Final Results for the GRC Supporting Technology Development Project for the 110-Watt Stirling Radioisotope Generator (SRG110)

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.

    2007-01-01

    From 1999 to 2006, the NASA Glenn Research Center (GRC) supported the development of a high-efficiency, nominal 110-We Stirling Radioisotope Generator (SRG110) for potential use on NASA missions, including deep space missions, Mars rovers, and lunar applications. Lockheed Martin (LM) was the system integrator for the SRG110, under contract to the Department of Energy (DOE). Infinia Corporation (formerly Stirling Technology Company) developed the Stirling convertor, first as a contractor to DOE and then under subcontract to LM. The SRG110 development has been redirected, and recent program changes have been made to significantly increase the specific power of the generator. System development of an Advanced Stirling Radioisotope Generator (ASRG) has now begun, using a lightweight, advanced convertor from Sunpower, Inc. This paper summarizes the results of the supporting technology effort that GRC completed for the SRG110. GRC tasks included convertor extended-duration testing in air and thermal vacuum environments, heater head life assessment, materials studies, permanent magnet aging characterization, linear alternator evaluations, structural dynamics testing, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) characterization, organic materials evaluations, reliability studies, and development of an end-to-end system dynamic model. Related efforts are now continuing in many of these areas to support ASRG development.

  4. Modular Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Mason, Lee S.; Schifer, Nicholas A.

    2016-01-01

    High-efficiency radioisotope power generators will play an important role in future NASA space exploration missions. Stirling Radioisotope Generators (SRGs) have been identified as a candidate generator technology capable of providing mission designers with an efficient, high-specific-power electrical generator. SRGs high conversion efficiency has the potential to extend the limited Pu-238 supply when compared with current Radioisotope Thermoelectric Generators (RTGs). Due to budgetary constraints, the Advanced Stirling Radioisotope Generator (ASRG) was canceled in the fall of 2013. Over the past year a joint study by NASA and the Department of Energy (DOE) called the Nuclear Power Assessment Study (NPAS) recommended that Stirling technologies continue to be explored. During the mission studies of the NPAS, spare SRGs were sometimes required to meet mission power system reliability requirements. This led to an additional mass penalty and increased isotope consumption levied on certain SRG-based missions. In an attempt to remove the spare power system, a new generator architecture is considered, which could increase the reliability of a Stirling generator and provide a more fault-tolerant power system. This new generator called the Modular Stirling Radioisotope Generator (MSRG) employs multiple parallel Stirling convertor/controller strings, all of which share the heat from the General Purpose Heat Source (GPHS) modules. For this design, generators utilizing one to eight GPHS modules were analyzed, which provided about 50 to 450 W of direct current (DC) to the spacecraft, respectively. Four Stirling convertors are arranged around each GPHS module resulting in from 4 to 32 Stirling/controller strings. The convertors are balanced either individually or in pairs, and are radiatively coupled to the GPHS modules. Heat is rejected through the housing/radiator, which is similar in construction to the ASRG. Mass and power analysis for these systems indicate that specific

  5. Modular Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Mason, Lee S.; Schifer, Nicholas A.

    2015-01-01

    High efficiency radioisotope power generators will play an important role in future NASA space exploration missions. Stirling Radioisotope Generators (SRG) have been identified as a candidate generator technology capable of providing mission designers with an efficient, high specific power electrical generator. SRGs high conversion efficiency has the potential to extend the limited Pu-238 supply when compared with current Radioisotope Thermoelectric Generators (RTG). Due to budgetary constraints, the Advanced Stirling Radioisotope Generator (ASRG) was canceled in the fall of 2013. Over the past year a joint study by NASA and DOE called the Nuclear Power Assessment Study (NPAS) recommended that Stirling technologies continue to be explored. During the mission studies of the NPAS, spare SRGs were sometimes required to meet mission power system reliability requirements. This led to an additional mass penalty and increased isotope consumption levied on certain SRG-based missions. In an attempt to remove the spare power system, a new generator architecture is considered which could increase the reliability of a Stirling generator and provide a more fault-tolerant power system. This new generator called the Modular Stirling Radioisotope Generator (MSRG) employs multiple parallel Stirling convertor/controller strings, all of which share the heat from the General Purpose Heat Source (GPHS) modules. For this design, generators utilizing one to eight GPHS modules were analyzed, which provide about 50 to 450 watts DC to the spacecraft, respectively. Four Stirling convertors are arranged around each GPHS module resulting in from 4 to 32 Stirling/controller strings. The convertors are balanced either individually or in pairs, and are radiatively coupled to the GPHS modules. Heat is rejected through the housing/radiator which is similar in construction to the ASRG. Mass and power analysis for these systems indicate that specific power may be slightly lower than the ASRG and

  6. Reliability Issues in Stirling Radioisotope Power Systems

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin R.; Schreiber, Jeffrey G.

    2004-01-01

    Stirling power conversion is a potential candidate for use in a Radioisotope Power System (RPS) for space science missions because it offers a multifold increase in the conversion efficiency of heat to electric power and reduced requirement of radioactive material. Reliability of an RPS that utilizes Stirling power conversion technology is important in order to ascertain long term successful performance. Owing to long life time requirement (14 years), it is difficult to perform long-term tests that encompass all the uncertainties involved in the design variables of components and subsystems comprising the RPS. The requirement for uninterrupted performance reliability and related issues are discussed, and some of the critical areas of concern are identified. An overview of the current on-going efforts to understand component life, design variables at the component and system levels, and related sources and nature of uncertainties are also discussed. Current status of the 110 watt Stirling Radioisotope Generator (SRG110) reliability efforts is described. Additionally, an approach showing the use of past experience on other successfully used power systems to develop a reliability plan for the SRG110 design is outlined.

  7. Reliability Issues in Stirling Radioisotope Power Systems

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey; Shah, Ashwin

    2005-01-01

    Stirling power conversion is a potential candidate for use in a Radioisotope Power System (RPS) for space science missions because it offers a multifold increase in the conversion efficiency of heat to electric power and reduced requirement of radioactive material. Reliability of an RPS that utilizes Stirling power conversion technology is important in order to ascertain long term successful performance. Owing to long life time requirement (14 years), it is difficult to perform long-term tests that encompass all the uncertainties involved in the design variables of components and subsystems comprising the RPS. The requirement for uninterrupted performance reliability and related issues are discussed, and some of the critical areas of concern are identified. An overview of the current on-going efforts to understand component life, design variables at the component and system levels, and related sources and nature of uncertainties are also discussed. Current status of the 110 watt Stirling Radioisotope Generator (SRG110) reliability efforts is described. Additionally, an approach showing the use of past experience on other successfully used power systems to develop a reliability plan for the SRG110 design is outlined.

  8. Development of a Multi-bus, Multi-source Reconfigurable Stirling Radioisotope Power System Test Bed

    NASA Technical Reports Server (NTRS)

    Coleman, Anthony S.

    2004-01-01

    The National Aeronautics and Space Administration (NASA) has typically used Radioisotope Thermoelectric Generators (RTG) as their source of electric power for deep space missions. A more efficient and potentially more cost effective alternative to the RTG, the high efficiency 110 watt Stirling Radioisotope Generator 110 (SRG110) is being developed by the Department of Energy (DOE), Lockheed Martin (LM), Stirling Technology Company (STC) and NASA Glenn Research Center (GRC). The SRG110 consists of two Stirling convertors (Stirling Engine and Linear Alternator) in a dual-opposed configuration, and two General Purpose Heat Source (GPHS) modules. Although Stirling convertors have been successfully operated as a power source for the utility grid and as a stand-alone portable generator, demonstration of the technology required to interconnect two Stirling convertors for a spacecraft power system has not been attempted. NASA GRC is developing a Power System Test Bed (PSTB) to evaluate the performance of a Stirling convertor in an integrated electrical power system application. This paper will describe the status of the PSTB and on-going activities pertaining to the PSTB in the NASA Thermal-Energy Conversion Branch of the Power and On-Board Propulsion Technology Division.

  9. Advanced Stirling Radioisotope Generator Life Certification Plan

    NASA Technical Reports Server (NTRS)

    Rusick, Jeffrey J.; Zampino, Edward J.

    2013-01-01

    An Advanced Stirling Radioisotope Generator (ASRG) power supply is being developed by the Department of Energy (DOE) in partnership with NASA for potential future deep space science missions. Unlike previous radioisotope power supplies for space exploration, such as the passive MMRTG used recently on the Mars Curiosity rover, the ASRG is an active dynamic power supply with moving Stirling engine mechanical components. Due to the long life requirement of 17 years and the dynamic nature of the Stirling engine, the ASRG project faced some unique challenges trying to establish full confidence that the power supply will function reliably over the mission life. These unique challenges resulted in the development of an overall life certification plan that emphasizes long-term Stirling engine test and inspection when analysis is not practical. The ASRG life certification plan developed is described.

  10. Status of the NASA Stirling Radioisotope Project

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    2007-01-01

    Free-piston Stirling power conversion has been considered a candidate for radioisotope power systems for space for more than a decade. Prior to the free-piston Stirling architecture, systems were designed with kinematic Stirling engines that used linkages and rotary alternators to convert heat to electricity. These systems were able to achieve long life by lightly loading the linkages; however, the live was nonetheless limited. When the free-piston configuration was initially proposed, it was thought to be attractive due to the relatively high conversion efficiency, acceptable mass, and the potential for long life and high reliability based on wear-free operation. These features have consistently been recognized by teams that have studied technology options for radioisotope space power systems. Since free-piston Stirling power conversion was first considered for space power applications, there have been major advances in three general areas of development: hardware that has demonstrated long-life and reliability, the success achieved by Stirling cryocoolers in space, and the overall developmental maturity of the technology for both space and terrestrial applications. Based on these advances, free-piston Stirling convertors are currently being developed for space power, and for a number of terrestrial applications. They commonly operate with the power, efficiency, life, and reliability as intended, and much of the development now centers on system integration. This paper will summarize the accomplishments of free-piston Stirling power conversion technology over the past decade, review the status of development with regard to space power, and discuss the challenges that remain.

  11. Stirling Convertor Technologies Being Developed for a Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.

    2003-01-01

    The Department of Energy, Lockheed Martin, Stirling Technology Company (STC), and the NASA Glenn Research Center are developing a high-efficiency Stirling Radioisotope Generator (SRG) for NASA space science missions. The SRG is being developed for multimission use, including providing electric power for unmanned Mars rovers and deep space missions. On Mars, rovers with SRGs would be used for missions that might not be able to use photovoltaic power systems, such as exploration at high Martian latitudes and missions of long duration. The projected SRG system efficiency of 23 percent will reduce the required amount of radioisotope by a factor of 4 or more in comparison to currently used Radioisotope Thermoelectric Generators. The Department of Energy recently named Lockheed Martin as the system integration contractor. Lockheed Martin has begun to develop the SRG engineering unit under contract to the Department of Energy, and has contract options to develop the qualification unit and the first flight units. The developers expect the SRG to produce about 114 Wdc at the beginning of mission, using two opposed Stirling convertors and two General Purpose Heat Source modules. STC previously developed the Stirling convertor under contract to the Department of Energy and is now providing further development as a subcontractor to Lockheed Martin. Glenn is conducting an in-house technology project to assist in developing the convertor for space qualification and mission implementation. A key milestone was recently reached with the accumulation of 12 000 hr of long-term aging on two types of neodymium-iron boron permanent magnets. These tests are characterizing any possible aging in the strength or demagnetization resistance of the magnets used in the linear alternator. Preparations are underway for a thermal/vacuum system demonstration and unattended operation during endurance testing of the 55-We Technology Demonstration Convertors. In addition, Glenn is developing a

  12. Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

    NASA Technical Reports Server (NTRS)

    Wang, Xiao-Yen J.; Fabanich, William Anthony; Schmitz, Paul C.

    2014-01-01

    This presentation describes the capabilities of three-dimensional thermal power model of advanced stirling radioisotope generator (ASRG). The performance of the ASRG is presented for different scenario, such as Venus flyby with or without the auxiliary cooling system.

  13. Reliability of Radioisotope Stirling Convertor Linear Alternator

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin; Korovaichuk, Igor; Geng, Steven M.; Schreiber, Jeffrey G.

    2006-01-01

    Onboard radioisotope power systems being developed and planned for NASA s deep-space missions would require reliable design lifetimes of up to 14 years. Critical components and materials of Stirling convertors have been undergoing extensive testing and evaluation in support of a reliable performance for the specified life span. Of significant importance to the successful development of the Stirling convertor is the design of a lightweight and highly efficient linear alternator. Alternator performance could vary due to small deviations in the permanent magnet properties, operating temperature, and component geometries. Durability prediction and reliability of the alternator may be affected by these deviations from nominal design conditions. Therefore, it is important to evaluate the effect of these uncertainties in predicting the reliability of the linear alternator performance. This paper presents a study in which a reliability-based methodology is used to assess alternator performance. The response surface characterizing the induced open-circuit voltage performance is constructed using 3-D finite element magnetic analysis. Fast probability integration method is used to determine the probability of the desired performance and its sensitivity to the alternator design parameters.

  14. Sodium Variable Conductance Heat Pipe for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Anderson, William G.; Walker, Kara

    2009-01-01

    In a Stirling radioisotope system, heat must continually be removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the converter stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, and also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) has been designed to allow multiple stops and restarts of the Stirling convertor in an Advanced Stirling Radioisotope Generator (ASRG). When the Stirling convertor is turned off, the VCHP will activate when the temperatures rises 30 C above the setpoint temperature. A prototype VCHP with sodium as the working fluid was fabricated and tested in both gravity aided and against gravity conditions for a nominal heater head temperature of 790 C. The results show very good agreement with the predictions and validate the model. The gas front was located at the exit of the reservoir when heater head temperature was 790 C while cooling was ON, simulating an operating Advanced Stirling Converter (ASC). When cooling stopped, the temperature increased by 30 C, allowing the gas front to move past the radiator, which transferred the heat to the case. After resuming the cooling flow, the front returned at the initial location turning OFF the VCHP. The against gravity working conditions showed a colder reservoir and faster transients.

  15. Development of Advanced Stirling Radioisotope Generator for Space Exploration

    NASA Astrophysics Data System (ADS)

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

    2007-01-01

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

  16. Development of Advanced Stirling Radioisotope Generator for Space Exploration

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  17. High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Walker, Kara L.; Anderson, William G.

    2009-01-01

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling convertor. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140 C while the heat losses caused by the addition of the VCHP are 1.8 W.

  18. Advanced radioisotope heat source for Stirling Engines

    NASA Astrophysics Data System (ADS)

    Dobry, T. J.; Walberg, G.

    2001-02-01

    The heat exchanger on a Stirling Engine requires a thermal energy transfer from a heat source to the engine through a very limited area on the heater head circumference. Designing an effective means to assure maximum transfer efficiency is challenging. A single General Purpose Heat Source (GPHS), which has been qualified for space operations, would satisfy thermal requirements for a single Stirling Engine that would produce 55 electrical watts. However, it is not efficient to transfer its thermal energy to the engine heat exchanger from its rectangular geometry. This paper describes a conceptual design of a heat source to improve energy transfer for Stirling Engines that may be deployed to power instrumentation on space missions. .

  19. Characterization of the Advanced Stirling Radioisotope Generator Engineering Unit 2

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Oriti, Salvatore M.; Schifer, Niholas A.

    2016-01-01

    Significant progress was made developing the Advanced Stirling Radioisotope Generator (ASRG) 140-W radioisotope power system. While the ASRG flight development project has ended, the hardware that was designed and built under the project is continuing to be tested to support future Stirling-based power system development. NASA Glenn Research Center recently completed the assembly of the ASRG Engineering Unit 2 (EU2). The ASRG EU2 consists of the first pair of Sunpower's Advanced Stirling Convertor E3 (ASC-E3) Stirling convertors mounted in an aluminum housing, and Lockheed Martin's Engineering Development Unit (EDU) 4 controller (a fourth-generation controller). The ASC-E3 convertors and Generator Housing Assembly (GHA) closely match the intended ASRG Qualification Unit flight design. A series of tests were conducted to characterize the EU2, its controller, and the convertors in the flight-like GHA. The GHA contained an argon cover gas for these tests. The tests included measurement of convertor, controller, and generator performance and efficiency; quantification of control authority of the controller; disturbance force measurement with varying piston phase and piston amplitude; and measurement of the effect of spacecraft direct current (DC) bus voltage on EU2 performance. The results of these tests are discussed and summarized, providing a basic understanding of EU2 characteristics and the performance and capability of the EDU 4 controller.

  20. Technology Development for a Stirling Radioisotope Power System

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Qiu, Songgang; White, Maurice A.

    2000-01-01

    NASA Glenn Research Center and the Department of Energy are developing a Stirling convertor for an advanced radioisotope power system to provide spacecraft on-board electric power for NASA deep space missions. NASA Glenn is addressing key technology issues through the use of two NASA Phase II SBIRs with Stirling Technology Company (STC) of Kennewick, WA. Under the first SBIR, STC demonstrated a synchronous connection of two thermodynamically independent free-piston Stirling convertors and a 40 to 50 fold reduction in vibrations compared to an unbalanced convertor. The second SBIR is for the development of an Adaptive Vibration Reduction System (AVRS) that will essentially eliminate vibrations over the mission lifetime, even in the unlikely event of a failed convertor. This paper presents the status and results for these two SBIR projects and also discusses a new NASA Glenn in-house project to provide supporting technology for the overall Stirling radioisotope power system development. Tasks for this new effort include convertor performance verification, controls development, heater head structural life assessment, magnet characterization and thermal aging tests, FEA analysis for a lightweight alternator concept, and demonstration of convertor operation under launch and orbit transfer load conditions.

  1. Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission

    NASA Astrophysics Data System (ADS)

    Schock, Alfred

    1994-07-01

    The preceding paper (Schock 1994) described conceptual designs and analytical results for five Radioisotope Thermoelectric Generator (RTG) options for the Pluto Fast Flyby (PFF) mission, and the present paper describes three Radioisotope Stirling Generator (RSG) options for the same mission. The RSG options are based on essentially the same radioisotope heat source modules used in previously flown RTGs and on designs and analyses of a 75-Watt free-piston Stirling engine produced by Mechanical Technology Incorporated (MTI) for NASA's Lewis Research Center. The integrated system design options presented were generated in a Fairchild Space study sponsored by the Department of Energy's Office of Special Applications, in support of ongoing PFF mission and spacecraft studies that the Jet Propulsion Laboratory (JPL) is conducting for the National Aeronautics and Space Administration (NASA). That study's NASA-directed goal is to reduce the spacecraft mass from its baseline value of 166 kg to -110 kg, which implies a mass goal of less than 10 kg for a power source able to deliver 69 Watts(e) at the end of the 9.2-year mission. In general, the Stirling options were found to be lighter than the thermoelectric options described in the preceding paper. But they are less mature, requiring more development, and entailing greater programmatic risk. The Stirling power system mass ranged from 7.3 kg (well below the 10-kg goal) for a non-redundant system to 11.3 kg for a redundant system able to maintain full power if one of its two engines fails. In fact, the latter system could deliver as much as 115 Watts(e) if desired by the mission planners.

  2. Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission

    SciTech Connect

    Schock, Alfred

    1993-10-01

    The preceding paper described conceptual designs and analytical results for five Radioisotope Thermoelectric Generator (RTG) options for the Pluto Fast Flyby (PFF) mission, and the present paper describes three Radioisotope Stirling Generator (RSG) options for the same mission. The RSG options are based on essentially the same radioisotope heat source modules used in previously flown RTGs and on designs and analyses of a 75-watt free-piston Stirling engine produced by Mechanical Technology Incorporated (MTI) for NASA's Lewis Research Center. The integrated system design options presented were generated in a Fairchild Space study sponsored by the Department of Energy's Office of Special Applications, in support of ongoing PFF mission and spacecraft studies that the Jet Propulsion Laboratory (JPL) is conducting for the National Aeronautics and Space Administration (NASA). That study's NASA-directed goal is to reduce the spacecraft mass from its baseline value of 166 kg to ~110 kg, which implies a mass goal of less than 10 kg for a power source able to deliver 69 watts(e) at the end of the 9.2-year mission. In general, the Stirling options were found to be lighter than the thermoelectric options described in the preceding paper. But they are less mature, requiring more development, and entailing greater programmatic risk. The Stirling power system mass ranged from 7.3 kg (well below the 10-kg goal) for a non-redundant system to 11.3 kg for a redundant system able to maintain full power if one of its engines fails. In fact, the latter system could deliver as much as 115 watts(e) if desired by the mission planners. There are 5 copies in the file.

  3. Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission

    SciTech Connect

    Schock, Alfred

    2012-01-19

    The preceding paper described conceptual designs and analytical results for five Radioisotope Thermoelectric Generator (RTG) options for the Pluto Fast Flyby (PFF) mission, and the present paper describes three Radioisotope Stirling Generator (RSG) options for the same mission. The RSG options are based on essentially the same radioisotope heat source modules used in previously flown RTGs and on designs and analyses of a 75-watt free-piston Stirling engine produced by Mechanical Technology Incorporated (MTI) for NASA's Lewis Research Center. The integrated system design options presented were generated in a Fairchild Space study sponsored by the Department of Energy's Office of Special Applications, in support of ongoing PFF mission and spacecraft studies that the Jet Propulsion Laboratory (JPL) is conducting for the National Aeronautics and Space Administration (NASA). That study's NASA-directed goal is to reduce the spacecraft mass from its baseline value of 166 kg to ~110 kg, which implies a mass goal of less than 10 kg for a power source able to deliver 69 watts(e) at the end of the 9.2-year mission. In general, the Stirling options were found to be lighter than the thermoelectric options described in the preceding paper. But they are less mature, requiring more development, and entailing greater programmatic risk. The Stirling power system mass ranged from 7.3 kg (well below the 10-kg goal) for a non-redundant system to 11.3 kg for a redundant system able to maintain full power if one of its engines fails. In fact, the latter system could deliver as much as 115 watts(e) if desired by the mission planners. There are 2 copies in the file.

  4. High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    SciTech Connect

    Tarau, Calin; Walker, Kara L.; Anderson, William G.

    2009-03-16

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling converter provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling engine. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140 deg. C while the heat losses caused by the addition of the VCHP are 1.8 W.

  5. Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Astrophysics Data System (ADS)

    Anderson, William G.; Tarau, Calin

    2008-01-01

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) was designed to allow multiple stops and restarts of the Stirling engine. A VCHP was designed for the Advanced Stirling Radioisotope Generator, with a 850 °C heater head temperature. The VCHP turns on with a ΔT of 30 °C, which is high enough to not risk standard ASRG operation but low enough to save most heater head life. This VCHP has a low mass, and low thermal losses for normal operation. In addition to the design, a proof-of-concept NaK VCHP was fabricated and tested. While NaK is normally not used in heat pipes, it has an advantage in that it is liquid at the reservoir operating temperature, while Na or K alone would freeze. The VCHP had two condensers, one simulating the heater head, and the other simulating the radiator. The experiments successfully demonstrated operation with the simulated heater head condenser off and on, while allowing the reservoir temperature to vary over 40 to 120 °C, the maximum range expected. In agreement with previous NaK heat pipe tests, the evaporator ΔT was roughly 70 °C, due to distillation of the NaK in the evaporator.

  6. High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Astrophysics Data System (ADS)

    Tarau, Calin; Walker, Kara L.; Anderson, William G.

    2009-03-01

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling converter provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling engine. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140° C while the heat losses caused by the addition of the VCHP are 1.8 W.

  7. Characterization of the Advanced Stirling Radioisotope Generator EU2

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Oriti, Salvatore M.; Schifer, Nicholas A.

    2015-01-01

    Significant progress was made developing the Advanced Stirling Radioisotope Generator (ASRG), a 140-watt radioisotope power system. While the ASRG flight development project has ended, the hardware that was designed and built under the project is continuing to be tested to support future Stirling-based power system development. NASA GRC recently completed the assembly of the ASRG Engineering Unit 2 (EU2). The ASRG EU2 consists of the first pair of Sunpower's ASC-E3 Stirling convertors mounted in an aluminum housing, and Lockheed Martin's Engineering Development Unit (EDU) 4 controller (a fourth generation controller). The ASC-E3 convertors and Generator Housing Assembly (GHA) closely match the intended ASRG Qualification Unit flight design. A series of tests were conducted to characterize the EU2, its controller, and the convertors in the flight-like GHA. The GHA contained an argon cover gas for these tests. The tests included: measurement of convertor, controller, and generator performance and efficiency, quantification of control authority of the controller, disturbance force measurement with varying piston phase and piston amplitude, and measurement of the effect of spacecraft DC bus voltage on EU2 performance. The results of these tests are discussed and summarized, providing a basic understanding of EU2 characteristics and the performance and capability of the EDU 4 controller.

  8. GRC Supporting Technology for NASA's Advanced Stirling Radioisotope Generator (ASRG)

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.

    2008-01-01

    From 1999 to 2006, the NASA Glenn Research Center (GRC) supported a NASA project to develop a high-efficiency, nominal 110-We Stirling Radioisotope Generator (SRG110) for potential use on NASA missions. Lockheed Martin was selected as the System Integration Contractor for the SRG110, under contract to the Department of Energy (DOE). The potential applications included deep space missions, and Mars rovers. The project was redirected in 2006 to make use of the Advanced Stirling Convertor (ASC) that was being developed by Sunpower, Inc. under contract to GRC, which would reduce the mass of the generator and increase the power output. This change would approximately double the specific power and result in the Advanced Stirling Radioisotope Generator (ASRG). The SRG110 supporting technology effort at GRC was replanned to support the integration of the Sunpower convertor and the ASRG. This paper describes the ASRG supporting technology effort at GRC and provides details of the contributions in some of the key areas. The GRC tasks include convertor extended-operation testing in air and in thermal vacuum environments, heater head life assessment, materials studies, permanent magnet characterization and aging tests, structural dynamics testing, electromagnetic interference and electromagnetic compatibility characterization, evaluation of organic materials, reliability studies, and analysis to support controller development.

  9. Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

    Anderson, William G.; Tarau, Calin

    2008-01-01

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling convertor provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) was designed to allow multiple stops and restarts of the Stirling engine. A VCHP turns on with a delta T of 30 C, which is high enough to not risk standard ASRG operation but low enough to save most heater head life. This VCHP has a low mass, and low thermal losses for normal operation. In addition to the design, a proof-of-concept NaK VCHP was fabricated and tested. While NaK is normally not used in heat pipes, it has an advantage in that it is liquid at the reservoir operating temperature, while Na or K alone would freeze. The VCHP had two condensers, one simulating the heater head, and the other simulating the radiator. The experiments successfully demonstrated operation with the simulated heater head condenser off and on, while allowing the reservoir temperature to vary over 40 to 120 C, the maximum range expected. In agreement with previous NaK heat pipe tests, the evaporator delta T was roughly 70 C, due to distillation of the NaK in the evaporator.

  10. Testing to Characterize the Advanced Stirling Radioisotope Generator Engineering Unit

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward; Schreiber, Jeffrey

    2010-01-01

    The Advanced Stirling Radioisotope Generator (ASRG), a high efficiency generator, is being considered for space missions. Lockheed Martin designed and fabricated an engineering unit (EU), the ASRG EU, under contract to the Department of Energy. This unit is currently undergoing extended operation testing at the NASA Glenn Research Center to generate performance data and validate life and reliability predictions for the generator and the Stirling convertors. It has also undergone performance tests to characterize generator operation while varying control parameters and system inputs. This paper summarizes and explains test results in the context of designing operating strategies for the generator during a space mission and notes expected differences between the EU performance and future generators.

  11. Parametric System Model for a Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.

    2014-01-01

    A Parametric System Model (PSM) was created in order to explore conceptual designs, the impact of component changes and power level on the performance of Stirling Radioisotope Generator (SRG). Using the General Purpose Heat Source (GPHS approximately 250 watt thermal) modules as the thermal building block around which a SRG is conceptualized, trade studies are performed to understand the importance of individual component scaling on isotope usage. Mathematical relationships based on heat and power throughput, temperature, mass and volume were developed for each of the required subsystems. The PSM uses these relationships to perform component and system level trades.

  12. Parametric System Model for a Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.

    2015-01-01

    A Parametric System Model (PSM) was created in order to explore conceptual designs, the impact of component changes and power level on the performance of the Stirling Radioisotope Generator (SRG). Using the General Purpose Heat Source (GPHS approximately 250 Wth) modules as the thermal building block from which a SRG is conceptualized, trade studies are performed to understand the importance of individual component scaling on isotope usage. Mathematical relationships based on heat and power throughput, temperature, mass, and volume were developed for each of the required subsystems. The PSM uses these relationships to perform component- and system-level trades.

  13. Advanced Stirling Convertor Development for NASA Radioisotope Power Systems

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Wilson, Scott D.; Collins, Josh

    2015-01-01

    Sunpower Inc.'s Advanced Stirling Convertor (ASC) initiated development under contract to the NASA Glenn Research Center and after a series of successful demonstrations, the ASC began transitioning from a technology development project to a flight development project. The ASC has very high power conversion efficiency making it attractive for future Radioisotope Power Systems (RPS) in order to make best use of the low plutonium-238 fuel inventory in the United States. In recent years, the ASC became part of the NASA and Department of Energy (DOE) Advanced Stirling Radioisotope Generator (ASRG) Integrated Project. Sunpower held two parallel contracts to produce ASCs, one with the DOE and Lockheed Martin to produce the ASC-F flight convertors, and one with NASA Glenn for the production of ASC-E3 engineering units, the initial units of which served as production pathfinders. The integrated ASC technical team successfully overcame various technical challenges that led to the completion and delivery of the first two pairs of flightlike ASC-E3 by 2013. However, in late fall 2013, the DOE initiated termination of the Lockheed Martin ASRG flight development contract driven primarily by budget constraints. NASA continues to recognize the importance of high-efficiency ASC power conversion for RPS and continues investment in the technology including the continuation of ASC-E3 production at Sunpower and the assembly of the ASRG Engineering Unit #2. This paper provides a summary of ASC technical accomplishments, overview of tests at Glenn, plans for continued ASC production at Sunpower, and status of Stirling technology development.

  14. Supporting Development for the Stirling Radioisotope Generator and Advanced Stirling Technology Development at NASA GRC

    NASA Astrophysics Data System (ADS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2005-02-01

    A high-efficiency, 110-We (watts electric) Stirling Radioisotope Generator (SRG110) for possible use on future NASA Space Science missions is being developed by the Department of Energy, Lockheed Martin, Stirling Technology Company (STC), and NASA Glenn Research Center (GRC). Potential mission use includes providing spacecraft onboard electric power for deep space missions and power for unmanned Mars rovers. GRC is conducting an in-house supporting technology project to assist in SRG110 development. One-, three-, and six-month heater head structural benchmark tests have been completed in support of a heater head life assessment. Testing is underway to evaluate the key epoxy bond of the permanent magnets to the linear alternator stator lamination stack. GRC has completed over 10,000 hours of extended duration testing of the Stirling convertors for the SRG110, and a three-year test of two Stirling convertors in a thermal vacuum environment will be starting shortly. GRC is also developing advanced technology for Stirling convertors, aimed at substantially improving the specific power and efficiency of the convertor and the overall generator. Sunpower, Inc. has begun the development of a lightweight Stirling convertor, under a NASA Research Announcement (NRA) award, that has the potential to double the system specific power to about 8 We/kg. GRC has performed random vibration testing of a lower-power version of this convertor to evaluate robustness for surviving launch vibrations. STC has also completed the initial design of a lightweight convertor. Status of the development of a multi-dimensional computational fluid dynamics code and high-temperature materials work on advanced superalloys, refractory metal alloys, and ceramics are also discussed.

  15. Supporting Development for the Stirling Radioisotope Generator and Advanced Stirling Technology Development at NASA Glenn

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2005-01-01

    A high-efficiency, 110-W(sub e) (watts electric) Stirling Radioisotope Generator (SRG110) for possible use on future NASA Space Science missions is being developed by the Department of Energy, Lockheed Martin, Stirling Technology Company (STC), and NASA Glenn Research Center (GRC). Potential mission use includes providing spacecraft onboard electric power for deep space missions and power for unmanned Mars rovers. GRC is conducting an in-house supporting technology project to assist in SRG110 development. One-, three-, and six-month heater head structural benchmark tests have been completed in support of a heater head life assessment. Testing is underway to evaluate the key epoxy bond of the permanent magnets to the linear alternator stator lamination stack. GRC has completed over 10,000 hours of extended duration testing of the Stirling convertors for the SRG110, and a three-year test of two Stirling convertors in a thermal vacuum environment will be starting shortly. GRC is also developing advanced technology for Stirling convertors, aimed at substantially improving the specific power and efficiency of the convertor and the overall generator. Sunpower, Inc. has begun the development of a lightweight Stirling convertor, under a NASA Research Announcement (NRA) award, that has the potential to double the system specific power to about 8 W(sub e) per kilogram. GRC has performed random vibration testing of a lowerpower version of this convertor to evaluate robustness for surviving launch vibrations. STC has also completed the initial design of a lightweight convertor. Status of the development of a multi-dimensional computational fluid dynamics code and high-temperature materials work on advanced superalloys, refractory metal alloys, and ceramics are also discussed.

  16. Stirling Research Laboratory Providing Independent Performance Verification of Convertors for a Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.

    2002-01-01

    The Department of Energy (DOE), Germantown, Maryland, Stirling Technology Company (STC), Kennewick, Washington, and NASA Glenn Research Center are developing a free-piston Stirling convertor for a high-efficiency Stirling Radioisotope Generator for NASA Space Science missions. This generator is being developed for multimission use, including providing electric power for unmanned Mars rovers and for deep space missions. STC is developing the 55-W Technology Demonstration Convertor (TDC) under contract to DOE. Glenn is conducting an in-house technology project to assist in developing the convertor for readiness for space qualification and mission implementation. As part of this effort, a Stirling Research Laboratory was established to test the TDC's and related technologies. A key task is providing an independent verification and validation of the TDC performance. Four TDC's are now being tested at Glenn. Acceptance testing has been completed for all convertors, and in general, performance agreed well with that achieved by STC prior to the delivery of the convertors. Performance mapping has also been completed on two of the convertors over a range of hot-end temperatures (450 to 650 C), cold-end temperatures (80 to 120 C), and piston amplitudes (5.2 to 6.2 mm). These test data are available online at http://www.grc.nasa.gov/WWW/tmsb/. The TDC's can be tested in either a horizontal orientation with dual-opposed convertors or in a vertical orientation with a single convertor. Synchronized dual-opposed pairs are used for dynamically balanced operation that results in very low levels of vibration. The Stirling Research Laboratory also supports launch environment testing of the TDC's in Glenn's Structural Dynamics Laboratory and electromagnetic interference and electromagnetic compatibility characterization and reduction efforts. In addition, the TDC's will be used for long-term endurance testing, and preparations are underway for unattended operation.

  17. Reliability Demonstration Approach for Advanced Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Ha, CHuong; Zampino, Edward; Penswick, Barry; Spronz, Michael

    2010-01-01

    Developed for future space missions as a high-efficiency power system, the Advanced Stirling Radioisotope Generator (ASRG) has a design life requirement of 14 yr in space following a potential storage of 3 yr after fueling. In general, the demonstration of long-life dynamic systems remains difficult in part due to the perception that the wearout of moving parts cannot be minimized, and associated failures are unpredictable. This paper shows a combination of systematic analytical methods, extensive experience gained from technology development, and well-planned tests can be used to ensure a high level reliability of ASRG. With this approach, all potential risks from each life phase of the system are evaluated and the mitigation adequately addressed. This paper also provides a summary of important test results obtained to date for ASRG and the planned effort for system-level extended operation.

  18. Development and Buildup of a Stirling Radioisotope Generator Electrical Simulator

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F.; Krasowski, Michael J.; Greer, Lawrence C.; Flatico, Joseph M.; Spina, Dan C.

    2008-01-01

    This paper describes the development of a Stirling Radioisotope Generator (SRG) Simulator for use in a prototype lunar robotic rover. The SRG developed at NASA Glenn Research Center (GRC) is a promising power source for the robotic exploration of the sunless areas of the moon. The simulator designed provides a power output similar to the SRG output of 5.7 A at 28 Vdc, while using ac wall power as the input power source. The designed electrical simulator provides rover developers the physical and electrical constraints of the SRG supporting parallel development of the SRG and rover. Parallel development allows the rover design team to embrace the SRG s unique constraints while development of the SRG is continued to a flight qualified version.

  19. Summary of Stirling Convertor Testing at NASA Glenn Research Center in Support of Stirling Radioisotope Power System Development

    NASA Technical Reports Server (NTRS)

    Schifer, Nicholas A.; Oriti, Salvatore M.

    2013-01-01

    The NASA Glenn Research Center (GRC) has been testing 100 We class, free-piston Stirling convertors for potential use in Stirling Radioisotope Power Systems (RPS) for space science and exploration missions. Free-piston Stirling convertors are capable of achieving a 38% conversion efficiency, making Stirling attractive for meeting future power system needs in light of the shrinking U.S. plutonium fuel supply. Convertors currently on test include four Stirling Technology Demonstration Convertors (TDCs), manufactured by the Stirling Technology Company (STC), and six Advanced Stirling Convertors (ASCs), manufactured by Sunpower, Inc. Total hours of operation is greater than 514,000 hours (59 years). Several tests have been initiated to demonstrate the functionality of Stirling convertors for space applications, including: in-air extended operation, thermal vacuum extended operation. Other tests have also been conducted to characterize Stirling performance in anticipated mission scenarios. Data collected during testing has been used to support life and reliability estimates, drive design changes and improve quality, and plan for expected mission scenarios. This paper will provide a summary of convertors tested at NASA GRC and discuss lessons learned through extended testing.

  20. Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

    NASA Technical Reports Server (NTRS)

    Wang, Xiao-Yen J.; Fabanich, William Anthony; Schmitz, Paul C.

    2014-01-01

    This paper presents recent thermal model results of the Advanced Stirling Radioisotope Generator (ASRG). The three-dimensional (3D) ASRG thermal power model was built using the Thermal Desktop(trademark) thermal analyzer. The model was correlated with ASRG engineering unit test data and ASRG flight unit predictions from Lockheed Martin's (LM's) I-deas(trademark) TMG thermal model. The auxiliary cooling system (ACS) of the ASRG is also included in the ASRG thermal model. The ACS is designed to remove waste heat from the ASRG so that it can be used to heat spacecraft components. The performance of the ACS is reported under nominal conditions and during a Venus flyby scenario. The results for the nominal case are validated with data from Lockheed Martin. Transient thermal analysis results of ASRG for a Venus flyby with a representative trajectory are also presented. In addition, model results of an ASRG mounted on a Cassini-like spacecraft with a sunshade are presented to show a way to mitigate the high temperatures of a Venus flyby. It was predicted that the sunshade can lower the temperature of the ASRG alternator by 20 C for the representative Venus flyby trajectory. The 3D model also was modified to predict generator performance after a single Advanced Stirling Convertor failure. The geometry of the Microtherm HT insulation block on the outboard side was modified to match deformation and shrinkage observed during testing of a prototypic ASRG test fixture by LM. Test conditions and test data were used to correlate the model by adjusting the thermal conductivity of the deformed insulation to match the post-heat-dump steady state temperatures. Results for these conditions showed that the performance of the still-functioning inboard ACS was unaffected.

  1. Extended Operation Testing of Stirling Convertors in Support of Stirling Radioisotope Power System Development

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Schreiber, Jeffre G.; Wilson, Scott D.; oriti, Salvatore M.; Cornell, Peggy; Schifer, Nicholas

    2008-01-01

    100 We class Stirling convertors began extended operation testing at NASA Glenn Research Center (GRC) in 2003 with a pair of Technology Demonstration Convertors (TDCs) operating in air. Currently, the number of convertors on extended operation test has grown to 12, including both TDCs and Advanced Stirling Convertors (ASCs) operating both in air and in thermal vacuum. Additional convertors and an electrically heated radioisotope generator will be put on test in the near future. This testing has provided data to support life and reliability estimates and the quality improvements and design changes that have been made to the convertor. The convertors operated 24/7 at the nominal amplitude and power levels. Performance data were recorded on an hourly basis. Techniques to monitor the convertors for change in internal operation included gas analysis, vibration measurements and acoustic emission measurements. This data provided a baseline for future comparison. This paper summarizes the results of over 145,000 hours of TDC testing and 40,000 hours of ASC testing and discusses trends in the data. Data shows the importance of improved materials, hermetic sealing, and quality processes in maintaining convertor performance over long life.

  2. Extended Operation Testing of Stirling Convertors in Support of Stirling Radioisotope Power System Development

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Schreiber, Jeffrey G.; Wilson, Scott D.; Oriti, Salvatore M.; Cornell, Peggy; Schifer, Nicholas

    2009-01-01

    100 We class Stirling convertors began extended operation testing at NASA Glenn Research Center (GRC) in 2003 with a pair of Technology Demonstration Convertors (TDCs) operating in air. Currently, the number of convertors on extended operation test has grown to 12, including both TDCs and Advanced Stirling Convertors (ASCs) operating both in air and in thermal vacuum. Additional convertors and an electrically heated radioisotope generator will be put on test in the near future. This testing has provided data to support life and reliability estimates and the quality improvements and design changes that have been made to the convertor. The convertors operated 24/7 at the nominal amplitude and power levels. Performance data were recorded on an hourly basis. Techniques to monitor the convertors for change in internal operation included gas analysis, vibration measurements, and acoustic emission measurements. This data provided a baseline for future comparison. This paper summarizes the results of over 145,000 hr of TDC testing and 40,000 hr of ASC testing and discusses trends in the data. Data shows the importance of improved materials, hermetic sealing, and quality processes in maintaining convertor performance over long life.

  3. Stirling Convertor for the Stirling Radioisotope Generator Tested as a Prelude to Transition to Flight

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.

    2004-01-01

    The Stirling Radioisotope Generator (SRG) is currently being developed by Lockheed Martin Astronautics (Valley Forge, PA) under contract to the Department of Energy (Germantown, MD). In support of this project, the NASA Glenn Research Center has established a near-term technology effort to provide some of the critical data to ensure a successful transition to flight for what will be the first dynamic power system to be used in space. The generator will be a high-efficiency electric power source for potential use on NASA space science missions. The generator will be able to operate in the vacuum of deep space or in an atmosphere such as on the surface of Mars. High system efficiency is obtained through the use of free-piston Stirling power-conversion technology. The power output of the generator will be greater than 100 W at the beginning of life, with the slow decline in power being largely due to decay of the plutonium heat source. Previously, Glenn's supporting technology efforts focused only on the most critical technical issues.

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

    NASA Astrophysics Data System (ADS)

    Shaltens, R. K.; Mason, L. S.; Schreiber, J. G.

    2001-01-01

    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.

  5. Test Program for Stirling Radioisotope Generator Hardware at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Bolotin, Gary S.; Oriti, Salvatore M.

    2014-01-01

    Stirling-based energy conversion technology has demonstrated the potential of high efficiency and low mass power systems for future space missions. This capability is beneficial, if not essential, to making certain deep space missions possible. Significant progress was made developing the Advanced Stirling Radioisotope Generator (ASRG), a 140-watt radioisotope power system. A variety of flight-like hardware, including Stirling convertors, controllers, and housings, was designed and built under the ASRG flight development project. To support future Stirling-based power system development NASA has proposals that, if funded, will allow this hardware to go on test at the NASA Glenn Research Center (GRC). While future flight hardware may not be identical to the hardware developed under the ASRG flight development project, many components will likely be similar, and system architectures may have heritage to ASRG. Thus the importance of testing the ASRG hardware to the development of future Stirling-based power systems cannot be understated. This proposed testing will include performance testing, extended operation to establish an extensive reliability database, and characterization testing to quantify subsystem and system performance and better understand system interfaces. This paper details this proposed test program for Stirling radioisotope generator hardware at NASA GRC. It explains the rationale behind the proposed tests and how these tests will meet the stated objectives.

  6. Test Program for Stirling Radioisotope Generator Hardware at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Bolotin, Gary S.; Oriti, Salvatore M.

    2015-01-01

    Stirling-based energy conversion technology has demonstrated the potential of high efficiency and low mass power systems for future space missions. This capability is beneficial, if not essential, to making certain deep space missions possible. Significant progress was made developing the Advanced Stirling Radioisotope Generator (ASRG), a 140-W radioisotope power system. A variety of flight-like hardware, including Stirling convertors, controllers, and housings, was designed and built under the ASRG flight development project. To support future Stirling-based power system development NASA has proposals that, if funded, will allow this hardware to go on test at the NASA Glenn Research Center. While future flight hardware may not be identical to the hardware developed under the ASRG flight development project, many components will likely be similar, and system architectures may have heritage to ASRG. Thus, the importance of testing the ASRG hardware to the development of future Stirling-based power systems cannot be understated. This proposed testing will include performance testing, extended operation to establish an extensive reliability database, and characterization testing to quantify subsystem and system performance and better understand system interfaces. This paper details this proposed test program for Stirling radioisotope generator hardware at NASA Glenn. It explains the rationale behind the proposed tests and how these tests will meet the stated objectives.

  7. Adaptive Vibration Reduction System Shown to Effectively Eliminate Vibrations for the Stirling Radioisotope Power System

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.

    2000-01-01

    Stirling Technology Company (STC), as part of a Small Business Innovation Research contract Phase II with the NASA Glenn Research Center at Lewis Field, is developing an Adaptive Vibration Reduction System (AVRS) that will effectively eliminate vibrations for the Stirling radioisotope power system. The AVRS will reduce vibration levels for two synchronized, opposed Stirling converters by a factor of 10 or more under normal operating conditions. Even more importantly, the AVRS will be adaptive and will be able to adjust to any changing converter conditions over the course of a mission. The Stirling converter is being developed by NASA and the Department of Energy (DOE) as a high-efficiency option for a radioisotope power system to provide onboard electric power for NASA deep space missions. The high Stirling efficiency of over 25 percent for this application will reduce the required amount of isotope by more than a factor of 3 in comparison to the current radioisotope thermoelectric generators (RTG s). Stirling is the most developed converter option of the advanced power technologies under consideration.

  8. Power characteristics of a Stirling radioisotope power system over the life of the mission

    NASA Astrophysics Data System (ADS)

    Schreiber, Jeffrey G.

    2001-02-01

    Stirling radioisotope power systems are presently being considered for use on long life deep space missions. Some applications that Stirling technology has been developed for in the past could control the heat input to the engine, as was the case in the Automotive Stirling Engine (ASE) program. The combustion system could change the rate at which fuel was burned in response to the Stirling heater head temperature and the desired set point. In other cases, heat input was not controlled. An example is the solar terrestrial Advanced Stirling Conversion System (ASCS), where the heat input was a function of solar intensity and the performance of the solar concentrator and receiver. The control system for this application would measure the Stirling heater head temperature and throttle the Stirling convertor to once again, maintain the Stirling heater head temperature at the desired set point. In both of these examples, the design was driven to be cost effective. In the Stirling radioisotope power system, the heat generated by the decay in plutonium is reduced with the half-life of the isotope, and the control system must be as simple as possible and still meet the mission requirements. The most simple control system would be one that allows the Stirling power convertor to autonomously change its operating conditions in direct response to the reduced heat input, with no intervention from the control system, merely seeking a new equilibrium point as the isotope decays. This paper presents an analysis of power system performance with this simple control system, which has no feedback and does not actively alter the operating point as the isotope decays. .

  9. Integration of Radioisotope Heat Source with Stirling Engine and Cooler for Venus Internal-Structure Mission

    SciTech Connect

    Schock, Alfred

    1993-10-01

    The primary mission goal is to perform long-term seismic measurements on Venus, to study its largely unknown internal structure. The principal problem is that most payload components cannot long survive Venus's harsh environment, 90 bars at 500 degrees C. To meet the mission life goal, such components must be protected by a refrigerated payload bay. JPL Investigators have proposed a mission concept employing a lander with a spherical payload bay cooled to 25 degrees C by a Stirling cooler powered by a radioisotope-heated Sitrling engine. To support JPL's mission study, NASA/Lewis and MTI have proposed a conceptual design for a hydraulically coupled Stirling engine and cooler, and Fairchild Space - with support of the Department of Energy - has proposed a design and integration scheme for a suitable radioisotope heat source. The key integration problem is to devise a simple, light-weight, and reliable scheme for forcing the radioisotope decay heat to flow through the Stirling engine during operation on Venus, but to reject that heat to the external environment when the Stirling engine and cooler are not operating (e.g., during the cruise phase, when the landers are surrounded by heat shields needed for protection during subsequent entry into the Venusian atmosphere.) A design and integration scheme for achieving these goals, together with results of detailed thermal analyses, are described in this paper. There are 7 copies in the file.

  10. Supporting Development for the Stirling Radioisotope Generator and Advanced Stirling Technology Development at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2005-01-01

    A high-efficiency, 110-We (watts electric) Stirling Radioisotope Generator (SRG110) for possible use on future NASA Space Science missions is being developed by the Department of Energy, Lockheed Martin, Stirling Technology Company (STC), and NASA Glenn Research Center (GRC). Potential mission use includes providing spacecraft onboard electric power for deep space missions and power for unmanned Mars rovers. GRC is conducting an in-house supporting technology project to assist in SRG110 development. One-, three-, and six-month heater head structural benchmark tests have been completed in support of a heater head life assessment. Testing is underway to evaluate the key epoxy bond of the permanent magnets to the linear alternator stator lamination stack. GRC has completed over 10,000 hours of extended duration testing of the Stirling convertors for the SRG110, and a three-year test of two Stirling convertors in a thermal vacuum environment will be starting shortly. GRC is also developing advanced technology for Stirling convertors, aimed at substantially improving the specific power and efficiency of the convertor and the overall generator. Sunpower, Inc. has begun the development of a lightweight Stirling convertor, under a NASA Research Announcement (NRA) award, that has the potential to double the system specific power to about 8 We/kg. GRC has performed random vibration testing of a lower-power version of this convertor to evaluate robustness for surviving launch vibrations. STC has also completed the initial design of a lightweight convertor. Status of the development of a multi-dimensional computational fluid dynamics code and high-temperature materials work on advanced superalloys, refractory metal alloys, and ceramics are also discussed.

  11. Sodium VCHP with Carbon-Carbon Radiator for Radioisotope Stirling Systems

    NASA Astrophysics Data System (ADS)

    Tarau, Calin; Anderson, William G.; Miller, William O.; Ramirez, Rogelio

    2010-01-01

    In a Stirling radioisotope system, heat must continually be removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling converter normally provides this cooling. If the Stirling convertor stops in the current system the insulation is designed to spoil, preventing damage to the GPHS at the cost of an earlier termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to allow multiple stops and restarts of the Stirling convertor. A sodium VCHP with a Haynes 230 envelope was designed and fabricated for the Advanced Stirling Radioisotope Generator (ASRG), with a baseline 850° C heater head temperature. When the Stirling convertor is stopped, the heat from the GPHS is rejected to the Cold Side Adapter Flange using a low-mass, carbon-carbon radiator. The VCHP is designed to activate with a AT of 30° C. The 880° C temperature when the Stirling convertor is stopped is high enough to avoid risking standard ASRG operation, but low enough to save most of the heater head life. The VCHP has low mass and low thermal losses for normal operation. The design has been modified from an earlier, stainless steel prototype with a nickel radiator. In addition to replacing the nickel radiator with a low mass carbon-carbon radiator, the radiator location has been moved from the ASRG case to the cold side adapter flange. This flange already removes two-thirds of the heat during normal operation, so it is optimized to transfer heat to the case. The VCHP was successfully tested with a turn-on ΔT of 30° C in three orientations: horizontal, gravity-aided, and against gravity.

  12. Extended Operation of Stirling Convertors

    NASA Technical Reports Server (NTRS)

    Roth, Mary Ellen; Schreiber, Jeffrey G.; Pepper, Stephen V.

    2004-01-01

    A high-efficiency 110 watt Stirling Radioisotope Generator 110 (SRG110) is being developed for potential NASA exploration missions. The SRG system efficiency is greater than 20%, making it an attractive candidate power system for deep space missions and unmanned rovers. The Department of Energy SRG110 Project team consists of the System Integrator, Lockheed Martin (LM), Stirling Technology Company (STC), and NASA Glenn Research Center (GRC). One of the GRC roles is to provide Independent Verification and Validation of the Stirling TDC's. At the request of LM, a part of this effort includes the extended operation of the TDC's in the dynamically balanced dual-opposed configuration. Performance data of the Stirling Converters over time is required to demonstrate that an SRG110 can meet long-duration mission requirements. A test plan and test system were developed to evaluate TDC's #13 and #14 steady-state performance for a minimum of 5000 hours and insure safe, round-the-clock operation of the TDC's. This paper will discuss the design and development, and status of the Extended Operation Test.

  13. Parametric Study of Radiator Concepts for a Stirling Radioisotope Power System Applicable to Deep Space Mission

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Tew, Roy C.; Thieme, Lanny G.

    2000-01-01

    The Department of Energy (DOE) and the NASA Glenn Research Center are developing a Stirling converter for an advanced radioisotope power system to provide spacecraft onboard electric power for NASA deep space missions. This high-efficiency converter is being evaluated as an alternative to replace the much lower efficiency radioisotope thermoelectric generator (RTG). The current power requirement (six years after beginning of mission (BOM) for a mission to Jupiter) is 210 W(sub e) (watts electric) to be generated by two separate power systems, one on each side of the spacecraft. Both two-converter and four-converter system designs are being considered, depending on the amount of required redundancy.

  14. External Magnetic Field Reduction Techniques for the Advanced Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.; Geng, Steven M.

    2013-01-01

    Linear alternators coupled to high efficiency Stirling engines are strong candidates for thermal-to-electric power conversion in space. However, the magnetic field emissions, both AC and DC, of these permanent magnet excited alternators can interfere with sensitive instrumentation onboard a spacecraft. Effective methods to mitigate the AC and DC electromagnetic interference (EMI) from solenoidal type linear alternators (like that used in the Advanced Stirling Convertor) have been developed for potential use in the Advanced Stirling Radioisotope Generator. The methods developed avoid the complexity and extra mass inherent in data extraction from multiple sensors or the use of shielding. This paper discusses these methods, and also provides experimental data obtained during breadboard testing of both AC and DC external magnetic field devices.

  15. Technology Development for a Stirling Radioisotope Power System for Deep Space Missions

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Qiu, Songgang; White, Maurice A.

    2000-01-01

    NASA Glenn Research Center and the Department of Energy (DOE) are developing a Stirling convertor for an advanced radioisotope power system to provide spacecraft on-board electric power for NASA deep space missions. NASA Glenn is addressing key technology issues through the use of two NASA Phase 2 SBIRs with Stirling Technology Company (STC) of Kennewick, WA. Under the first SBIR, STC demonstrated a 40 to 50 fold reduction in vibrations, compared to an unbalanced convertor, with a synchronous connection of two thermodynamically independent free-piston Stirling convertors. The second SBIR is for the development of an Adaptive Vibration Reduction System (AVRS) that will essentially eliminate vibrations over a mission lifetime, even in the unlikely event of a failed convertor. This paper discusses the status and results for these two SBIR projects and also presents results for characterizing the friction factor of high-porosity random fiber regenerators that are being used for this application.

  16. Status of an advanced radioisotope space power system using free-piston Stirling technology

    SciTech Connect

    White, M.A,; Qiu, S.; Erbeznik, R.M.; Olan, R.W.; Welty, S.C.

    1998-07-01

    This paper describes a free-piston Stirling engine technology project to demonstrate a high efficiency power system capable of being further developed for deep space missions using a radioisotope (RI) heat source. The key objective is to develop a power system with an efficiency exceeding 20% that can function with a high degree of reliability for 10 years or longer on deep space missions. Primary issues being addressed for Stirling space power systems are weight and the vibration associated with reciprocating pistons. Similar weight and vibration issues have been successfully addressed with Stirling cryocoolers, which are the accepted standard for cryogenic cooling in space. Integrated long-life Stirling engine-generator (or convertor) operation has been demonstrated by the terrestrial Radioisotope Stirling Generator (RSG) and other Stirling Technology Company (STC) programs. Extensive RSG endurance testing includes more than 40,000 maintenance-free, degradation-free hours for the complete convertor, in addition to several critical component and subsystem endurance tests. The Stirling space power convertor project is being conducted by STC under DOE Contract, and NASA SBIR Phase II contracts. The DOE contract objective is to demonstrate a two-convertor module that represents half of a nominal 150-W(e) power system. Each convertor is referred to as a Technology Demonstration Convertor (TDC). The ultimate Stirling power system would be fueled by three general purpose heat source (GPHS) modules, and is projected to produce substantially more electric power than the 150-watt target. The system is capable of full power output with one failed convertor. One NASA contract, nearing completion, uses existing 350-W(e) RG-350 convertors to evaluate interactivity of two back-to-back balanced convertors with various degrees of electrical and mechanical interaction. This effort has recently provided the first successful synchronization of two convertors by means of parallel

  17. Advanced Stirling Radioisotope Generator (ASRG) Thermal Power Model in MATLAB

    NASA Technical Reports Server (NTRS)

    Wang, Xiao-Yen, J.

    2012-01-01

    This paper presents a one-dimensional steady-state mathematical thermal power model of the ASRG. It aims to provide a guideline of understanding how the ASRG works and what can change its performance. The thermal dynamics and energy balance of the generator is explained using the thermal circuit of the ASRG. The Stirling convertor performance map is used to represent the convertor. How the convertor performance map is coupled in the thermal circuit is explained. The ASRG performance characteristics under i) different sink temperatures and ii) over the years of mission (YOM) are predicted using the one-dimensional model. Two Stirling converter control strategies, i) fixing the hot-end of temperature of the convertor by adjusting piston amplitude and ii) fixing the piston amplitude, were tested in the model. Numerical results show that the first control strategy can result in a higher system efficiency than the second control strategy when the ambient gets warmer or the general-purpose heat source (GPHS) fuel load decays over the YOM. The ASRG performance data presented in this paper doesn't pertain to the ASRG flight unit. Some data of the ASRG engineering unit (EU) and flight unit that are available in public domain are used in this paper for the purpose of numerical studies.

  18. NaK Variable Conductance Heat Pipe for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Anderson, William G.; Walker, Kara

    2008-01-01

    In a Stirling radioisotope power system, heat must continually be removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides most of this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending use of that convertor for the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) was designed to allow multiple stops and restarts of the Stirling convertor. In the design of the VCHP for the Advanced Stirling Radioisotope Generator, the VCHP reservoir temperature can vary between 40 and 120 C. While sodium, potassium, or cesium could be used as the working fluid, their melting temperatures are above the minimum reservoir temperature, allowing working fluid to freeze in the reservoir. In contrast, the melting point of NaK is -12 C, so NaK can't freeze in the reservoir. One potential problem with NaK as a working fluid is that previous tests with NaK heat pipes have shown that NaK heat pipes can develop temperature non-uniformities in the evaporator due to NaK's binary composition. A NaK heat pipe was fabricated to measure the temperature non-uniformities in a scale model of the VCHP for the Stirling Radioisotope system. The temperature profiles in the evaporator and condenser were measured as a function of operating temperature and power. The largest delta T across the condenser was 2S C. However, the condenser delta T decreased to 16 C for the 775 C vapor temperature at the highest heat flux applied, 7.21 W/ square cm. This decrease with increasing heat flux was caused by the increased mixing of the sodium and potassium in the vapor. This temperature differential is similar to the temperature variation in this ASRG heat transfer interface without a heat pipe, so NaK can be used as the VCHP working fluid.

  19. System-Level Testing of the Advanced Stirling Radioisotope Generator Engineering Hardware

    NASA Technical Reports Server (NTRS)

    Chan, Jack; Wiser, Jack; Brown, Greg; Florin, Dominic; Oriti, Salvatore M.

    2014-01-01

    To support future NASA deep space missions, a radioisotope power system utilizing Stirling power conversion technology was under development. This development effort was performed under the joint sponsorship of the Department of Energy and NASA, until its termination at the end of 2013 due to budget constraints. The higher conversion efficiency of the Stirling cycle compared with that of the Radioisotope Thermoelectric Generators (RTGs) used in previous missions (Viking, Pioneer, Voyager, Galileo, Ulysses, Cassini, Pluto New Horizons and Mars Science Laboratory) offers the advantage of a four-fold reduction in Pu-238 fuel, thereby extending its limited domestic supply. As part of closeout activities, system-level testing of flight-like Advanced Stirling Convertors (ASCs) with a flight-like ASC Controller Unit (ACU) was performed in February 2014. This hardware is the most representative of the flight design tested to date. The test fully demonstrates the following ACU and system functionality: system startup; ASC control and operation at nominal and worst-case operating conditions; power rectification; DC output power management throughout nominal and out-of-range host voltage levels; ACU fault management, and system command / telemetry via MIL-STD 1553 bus. This testing shows the viability of such a system for future deep space missions and bolsters confidence in the maturity of the flight design.

  20. Development of a Power Electronics Controller for the Advanced Stirling Radioisotope Generator

    NASA Technical Reports Server (NTRS)

    Leland, Douglas K.; Priest, Joel F.; Keiter, Douglas E.; Schreiber, Jeffrey G.

    2008-01-01

    Under a U.S. Department of Energy program for radioisotope power systems, Lockheed Martin is developing an Engineering Unit of the Advanced Stirling Radioisotope Generator (ASRG). This is an advanced version of the previously reported SRG110 generator. The ASRG uses Advanced Stirling Convertors (ASCs) developed by Sunpower Incorporated under a NASA Research Announcement contract. The ASRG makes use of a Stirling controller based on power electronics that eliminates the tuning capacitors. The power electronics controller synchronizes dual-opposed convertors and maintains a fixed frequency operating point. The controller is single-fault tolerant and uses high-frequency pulse width modulation to create the sinusoidal currents that are nearly in phase with the piston velocity, eliminating the need for large series tuning capacitors. Sunpower supports this effort through an extension of their controller development intended for other applications. Glenn Research Center (GRC) supports this effort through system dynamic modeling, analysis and test support. The ASRG design arrived at a new baseline based on a system-level trade study and extensive feedback from mission planners on the necessity of single-fault tolerance. This paper presents the baseline design with an emphasis on the power electronics controller detailed design concept that will meet space mission requirements including single fault tolerance.

  1. Effect of inert cover gas on performance of radioisotope Stirling space power system

    NASA Astrophysics Data System (ADS)

    Carpenter, R.; Kumar, V.; Or, C.; Schock, A.

    2001-02-01

    This paper describes an updated Orbital design of a radioisotope Stirling power system and its predicted performance at the beginning and end of a six-year mission to the Jovian moon Europa. The design is based on General Purpose Heat Source (GPHS) modules identical to those previously developed and safety-qualified by the Department of Energy (DOE) which were successfully launched on missions to Jupiter and Saturn by the Jet Propulsion Laboratory (JPL). In each generator, the heat produced by the decay of the Pu-238 isotope is converted to electric power by two free-piston Stirling engines and linear alternators developed by Stirling Technology Company (STC), and their rejected waste heat is transported to radiators by heat pipes. The principal difference between the proposed system design and previous Orbital designs (Or et al., 2000) is the thermal insulation between the heat source and the generator's housing. Previous designs had employed multifoil insulation, whereas the design described here employs Min-K-1800 thermal insulation. Such insulation had been successfully used by Teledyne and GE in earlier RTGs (Radioisotope Thermoelectric Generators). Although Min-K is a much poorer insulator than multifoil in vacuum and requires a substantially greater thickness for equivalent performance, it offers compensating advantages. Specifically it makes it possible to adjust the generator's BOM temperatures by filling its interior volume with inert cover gas. This makes it possible to meet the generator's BOM and EOM performance goals without exceeding its allowable temperature at the beginning of the mission. .

  2. Effect of Inert Cover Gas on Performance of Radioisotope Stirling Space Power System

    SciTech Connect

    Carpenter, Robert; Kumar, V; Ore, C; Schock, Alfred

    2001-01-01

    This paper describes an updated Orbital design of a radioisotope Stirling power system and its predicted performance at the beginning and end of a six-year mission to the Jovian moon Europa. The design is based on General Purpose Heat Source (GPHS) modules identical to those previously developed and safety-qualified by the Department of Energy (DOE) which were successfully launched to Jupiter and Saturn by the Jet Propulsion Laboratory (JPL). In each generator, the heat produced by the decay of the Pu-238 isotope is converted to electric power by two free-piston Stirling engines and linear alternators developed by Stirling Technology Company (STC), and their rejected waste heat is transported to radiators by heat pipes. The principal difference between the proposed system design and previous Orbital designs (Or et al. 2000) is the thermal insulation between the heat source and the generator's housing. Previous designs had employed multifoil insulation, whereas the design described here employs Min-K-1800 thermal insulation. Such insulation had been successfully used by Teledyne and GE in earlier RTGs (Radioisotope Thermoelectric Generators). Although Min-K is a much poorer insulator than multifoil in vacuum and requires a substantially greater thickness for equivalent performance, it offers compensating advantages. Specifically it makes it possible to adjust the generator's BOM temperatures by filling its interior volume with inert cover gas. This makes it possible to meet the generator's BOM and EOM performance goals without exceeding its allowable temperature at the beginning of the mission.

  3. NASA Glenn Research Center Support of the Advanced Stirling Radioisotope Generator Project

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.; Wong, Wayne A.

    2015-01-01

    A high-efficiency radioisotope power system was being developed for long-duration NASA space science missions. The U.S. Department of Energy (DOE) managed a flight contract with Lockheed Martin Space Systems Company to build Advanced Stirling Radioisotope Generators (ASRGs), with support from NASA Glenn Research Center. DOE initiated termination of that contract in late 2013, primarily due to budget constraints. Sunpower, Inc., held two parallel contracts to produce Advanced Stirling Convertors (ASCs), one with Lockheed Martin to produce ASC-F flight units, and one with Glenn for the production of ASC-E3 engineering unit "pathfinders" that are built to the flight design. In support of those contracts, Glenn provided testing, materials expertise, Government-furnished equipment, inspection capabilities, and related data products to Lockheed Martin and Sunpower. The technical support included material evaluations, component tests, convertor characterization, and technology transfer. Material evaluations and component tests were performed on various ASC components in order to assess potential life-limiting mechanisms and provide data for reliability models. Convertor level tests were conducted to characterize performance under operating conditions that are representative of various mission conditions. Despite termination of the ASRG flight development contract, NASA continues to recognize the importance of high-efficiency ASC power conversion for Radioisotope Power Systems (RPS) and continues investment in the technology, including the continuation of the ASC-E3 contract. This paper describes key Government support for the ASRG project and future tests to be used to provide data for ongoing reliability assessments.

  4. Design of a Facility to Test the Advanced Stirling Radioisotope Generator Engineering Unit

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Schreiber, Jeffrey G.; Oriti, Salvatore M.; Meer, David W.; Brace, Michael H.; Dugala, Gina

    2009-01-01

    The Advanced Stirling Radioisotope Generator (ASRG) is being considered to power deep space missions. An engineering unit, the ASRG-EU, was designed and fabricated by Lockheed Martin under contract to the Department of Energy. This unit is currently on an extended operation test at NASA Glenn Research Center to generate performance data and validate the life and reliability predictions for the generator and the Stirling convertors. A special test facility was designed and built for testing the ASRG-EU. Details of the test facility design are discussed. The facility can operate the convertors under AC bus control or with the ASRG-EU controller. It can regulate input thermal power in either a fixed temperature or fixed power mode. An enclosure circulates cooled air around the ASRG-EU to remove heat rejected from the ASRG-EU by convection. A custom monitoring and data acquisition system supports the test. Various safety features, which allow 2417 unattended operation, are discussed.

  5. Design of a Facility to Test the Advanced Stirling Radioisotope Generator Engineering Unit

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Schreiber, Jeffrey G.; Oriti, Salvatore M.; Meer, David W.; Brace, Michael H.; Dugala, Gina

    2010-01-01

    The Advanced Stirling Radioisotope Generator (ASRG), a high efficiency generator, is being considered for space missions. An engineering unit, the ASRG engineering unit (EU), was designed and fabricated by Lockheed Martin under contract to the Department of Energy. This unit is currently under extended operation test at the NASA Glenn Research Center (GRC) to generate performance data and validate the life and reliability predictions for the generator and the Stirling convertors. A special test facility was designed and built for the ASRG EU. This paper summarizes details of the test facility design, including the mechanical mounting, heat-rejection system, argon system, control systems, and maintenance. The effort proceeded from requirements definition through design, analysis, build, and test. Initial testing and facility performance results are discussed.

  6. NASA GRC Technology Development Project for a Stirling Radioisotope Power System

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2000-01-01

    NASA Glenn Research Center (GRC), the Department of Energy (DOE), and Stirling Technology Company (STC) are developing a Stirling convertor for an advanced radioisotope power system to provide spacecraft on-board electric power for NASA deep space missions. NASA GRC is conducting an in-house project to provide convertor, component, and materials testing and evaluation in support of the overall power system development. A first characterization of the DOE/STC 55-We Stirling Technology Demonstration Convertor (TDC) under the expected launch random vibration environment was recently completed in the NASA GRC Structural Dynamics Laboratory. Two TDCs also completed an initial electromagnetic interference (EMI) characterization at NASA GRC while being tested in a synchronized, opposed configuration. Materials testing is underway to support a life assessment of the heater head, and magnet characterization and aging tests have been initiated. Test facilities are now being established for an independent convertor performance verification and technology development. A preliminary Failure Mode Effect Analysis (FMEA), initial finite element analysis (FEA) for the linear alternator, ionizing radiation survivability assessment, and radiator parametric study have also been completed. This paper will discuss the status, plans, and results to date for these efforts.

  7. Status update of a free-piston Stirling convertor for radioisotope space power systems

    NASA Astrophysics Data System (ADS)

    White, Maurice; Qiu, Songgang; Augenblick, Jack; Peterson, Allen; Faultersack, Frank

    2001-02-01

    Free-piston Stirling engines offer a relatively mature technology that is well-suited for advanced, high-efficiency radioisotope space power systems. This paper updates results from a combination of DOE and NASA contracts with Stirling Technology Company (STC). These contracts have demonstrated STC's Stirling convertor technology in a configuration and power level representative of a space power system. Based on demonstrated performance, long-life maintenance-free technology heritage, and success with aggressively imposed vibration testing. DOE has awarded system integration contracts to Boeing, Lockheed Martin and Teledyne Energy Systems. The objectives of these competitive Phase I contracts are to develop complete spacecraft power system conceptual designs based on the STC Stirling convertor, and to plan subsequent phases for two launches. Performance results for the DOE 55-W(e) Technology Demonstration Convertors (TDC's) have met original projections. Although the TDC's were intended only for technology demonstration, they have achieved very aggressive efficiency goals, demonstrated convertor-induced vibration levels below the Jet Propulsion Laboratory (JPL) specifications, passed a simulated launch load vibration test at 0.2 g2/Hz (12.3 g rms), and met EMI/EMC goals for most contemplated missions. No consideration for EMI reduction was included in the TDC design. Minor changes are underway to reduce EMI levels, with a goal of meeting specifications for missions such as Solar Probe with highly sensitive instrumentation. The long-term objective for DOE is to develop a power system with a system efficiency exceeding 20% that can function with a high degree of reliability for 10 years and longer on deep space missions. .

  8. Testing of the Advanced Stirling Radioisotope Generator Engineering Unit at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.

    2013-01-01

    The Advanced Stirling Radioisotope Generator (ASRG) is a high-efficiency generator being developed for potential use on a Discovery 12 space mission. Lockheed Martin designed and fabricated the ASRG Engineering Unit (EU) under contract to the Department of Energy. This unit was delivered to NASA Glenn Research Center in 2008 and has been undergoing extended operation testing to generate long-term performance data for an integrated system. It has also been used for tests to characterize generator operation while varying control parameters and system inputs, both when controlled with an alternating current (AC) bus and with a digital controller. The ASRG EU currently has over 27,000 hours of operation. This paper summarizes all of the tests that have been conducted on the ASRG EU over the past 3 years and provides an overview of the test results and what was learned.

  9. Advanced Stirling Radioisotope Generator Thermal Power Model in Thermal Desktop SINDA/FLUINT Analyzer

    NASA Technical Reports Server (NTRS)

    Wang, Xiao-Yen; Fabanich, William A.; Schmitz, Paul C.

    2012-01-01

    This paper presents a three-dimensional Advanced Stirling Radioisotope Generator (ASRG) thermal power model that was built using the Thermal Desktop SINDA/FLUINT thermal analyzer. The model was correlated with ASRG engineering unit (EU) test data and ASRG flight unit predictions from Lockheed Martin's Ideas TMG thermal model. ASRG performance under (1) ASC hot-end temperatures, (2) ambient temperatures, and (3) years of mission for the general purpose heat source fuel decay was predicted using this model for the flight unit. The results were compared with those reported by Lockheed Martin and showed good agreement. In addition, the model was used to study the performance of the ASRG flight unit for operations on the ground and on the surface of Titan, and the concept of using gold film to reduce thermal loss through insulation was investigated.

  10. Advanced Stirling Radioisotope Generator Engineering Unit 2 (ASRG EU2) Final Assembly

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.

    2015-01-01

    NASA Glenn Research Center (GRC) has recently completed the assembly of a unique Stirling generator test article for laboratory experimentation. Under the Advanced Stirling Radioisotope Generator (ASRG) flight development contract, NASA GRC initiated a task to design and fabricate a flight-like generator for in-house testing. This test article was given the name ASRG Engineering Unit 2 (EU2) as it was effectively the second engineering unit to be built within the ASRG project. The intent of the test article was to duplicate Lockheed Martin's qualification unit ASRG design as much as possible to enable system-level tests not previously possible at GRC. After the cancellation of the ASRG flight development project, the decision was made to continue the EU2 build, and make use of a portion of the hardware from the flight development project. GRC and Lockheed Martin engineers collaborated to develop assembly procedures, leveraging the valuable knowledge gathered by Lockheed Martin during the ASRG development contract. The ASRG EU2 was then assembled per these procedures at GRC with Lockheed Martin engineers on site. The assembly was completed in August 2014. This paper details the components that were used for the assembly, and the assembly process itself.

  11. Natural Convection Cooling of the Advanced Stirling Radioisotope Generator Engineering Unit

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Hill, Dennis

    2011-01-01

    After fueling and prior to launch, the Advanced Stirling Radioisotope Generator (ASRG) will be stored for a period of time then moved to the launch pad for integration with the space probe and mounting on the launch vehicle. During this time, which could be as long as 3 years, the ASRG will operate continuously with heat rejected from the housing and fins. Typically, the generator will be cooled by forced convection using fans. During some of the ground operations, maintaining forced convection may add significant complexity, so allowing natural convection may simplify operations. A test was conducted on the ASRG Engineering Unit (EU) to quantify temperatures and operating parameters with natural convection only and determine if the EU could be safely operated in such an environment. The results show that with natural convection cooling the ASRG EU Stirling convertor pressure vessel temperatures and other parameters had significant margins while the EU was operated for several days in this configuration. Additionally, an update is provided on ASRG EU testing at NASA Glenn Research Center, where the ASRG EU has operated for over 16,000 hr and underwent extensive testing.

  12. Feasibility study of a 110 watt per kilogram lightweight solar array system

    NASA Technical Reports Server (NTRS)

    Shepard, N. F.; Stahle, C. V.; Hanson, K. L.; Schneider, A.; Blomstrom, L. E.; Hansen, W. T.; Kirpich, A.

    1973-01-01

    The feasibility of a 10,000 watt solar array panel which has a minimum power-to-mass ratio of 110 watt/kg is discussed. The application of this ultralightweight solar array to three possible missions was investigated. With the interplanetary mission as a baseline, the constraining requirements for a geosynchronous mission and for a manned space station mission are presented. A review of existing lightweight solar array system concepts revealed that changes in the system approach are necessary to achieve the specified 110 watt/kg goal. A comprehensive review of existing component technology is presented in the areas of thin solar cells, solar cell covers, welded interconnectors, substrates and deployable booms. Advances in the state-of-the-art of solar cell and deployable boom technology were investigated. System level trade studies required to select the optimum boom bending stiffness, system aspect ratio, bus voltage level, and solar cell circuit arrangement are reported. Design analysis tasks included the thermal analysis of the solar cell blanket, thermal stress analysis of the solar cell interconnectors/substrate, and the thermostructural loading of the deployed boom.

  13. Extended Operation of Stirling Convertors in a Thermal Vacuum Environment

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.

    2006-01-01

    A 110 watt Stirling Radioisotope Generator (SRG110) is being developed for potential use on future NASA exploration missions. The development effort is being performed by Lockheed Martin under contract to the Department of Energy (DOE). Infinia, Corp. supplies the free-piston Stirling power convertors, and NASA Glenn Research Center (GRC) provides support to the effort in a range of technologies. This generator features higher efficiency and specific power compared to alternatives. One potential application for the generator would entail significant cruise time in the vacuum of deep space. A test has been initiated at GRC to demonstrate functionality of the Stirling convertors in a thermal vacuum environment. The test article resembles the configuration of the SRG110, however the requirement for low mass was not considered. This test demonstrates the operation of the Stirling convertors in the thermal vacuum environment, simulating deep space, over an extended period of operation. The status of the test as well as the data gathered will be presented in this paper.

  14. Preliminary test results from a free-piston Stirling engine technology demonstration program to support advanced radioisotope space power applications

    NASA Astrophysics Data System (ADS)

    White, Maurice A.; Qiu, Songgang; Augenblick, Jack E.

    2000-01-01

    Free-piston Stirling engines offer a relatively mature, proven, long-life technology that is well-suited for advanced, high-efficiency radioisotope space power systems. Contracts from DOE and NASA are being conducted by Stirling Technology Company (STC) for the purpose of demonstrating the Stirling technology in a configuration and power level that is representative of an eventual space power system. The long-term objective is to develop a power system with an efficiency exceeding 20% that can function with a high degree of reliability for up to 15 years on deep space missions. The current technology demonstration convertors (TDC's) are completing shakedown testing and have recently demonstrated performance levels that are virtually identical to projections made during the preliminary design phase. This paper describes preliminary test results for power output, efficiency, and vibration levels. These early results demonstrate the ability of the free-piston Stirling technology to exceed objectives by approximately quadrupling the efficiency of conventional radioisotope thermoelectric generators (RTG's). .

  15. Radioisotope Stirling Engine Powered Airship for Atmospheric and Surface Exploration of Titan

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Cataldo, Robert L.

    2014-01-01

    The feasibility of an advanced Stirling radioisotope generator (ASRG) powered airship for the near surface exploration of Titan was evaluated. The analysis did not consider the complete mission only the operation of the airship within the atmosphere of Titan. The baseline airship utilized two ASRG systems with a total of four general-purpose heat source (GPHS) blocks. Hydrogen gas was used to provide lift. The ASRG systems, airship electronics and controls and the science payload were contained in a payload enclosure. This enclosure was separated into two sections, one for the ASRG systems and the other for the electronics and payload. Each section operated at atmospheric pressure but at different temperatures. The propulsion system consisted of an electric motor driving a propeller. An analysis was set up to size the airship that could operate near the surface of Titan based on the available power from the ASRGs. The atmospheric conditions on Titan were modeled and used in the analysis. The analysis was an iterative process between sizing the airship to carry a specified payload and the power required to operate the electronics, payload and cooling system as well as provide power to the propulsion system to overcome the drag on the airship. A baseline configuration was determined that could meet the power requirements and operate near the Titan surface. From this baseline design additional trades were made to see how other factors affected the design such as the flight altitude and payload mass and volume.

  16. Advanced Stirling Convertor Dual Convertor Controller Testing at NASA Glenn Research Center in the Radioisotope Power Systems System Integration Laboratory

    NASA Technical Reports Server (NTRS)

    Dugala, Gina M.; Taylor, Linda M.; Bell, Mark E.; Dolce, James L.; Fraeman, Martin; Frankford, David P.

    2015-01-01

    NASA Glenn Research Center (GRC) developed a non-nuclear representation of a Radioisotope Power System (RPS) consisting of a pair of Advanced Stirling Convertors (ASC), a Dual Convertor Controller (DCC) EM (engineering model) 2 & 3, and associated support equipment, which were tested in the Radioisotope Power Systems System Integration Laboratory (RSIL). The DCC was designed by the Johns Hopkins University/Applied Physics Laboratory (JHU/APL) to actively control a pair of Advanced Stirling Convertors (ASC). The first phase of testing included a Dual Advanced Stirling Convertor Simulator (DASCS) which was developed by JHU/APL and simulates the operation and electrical behavior of a pair of ASC's in real time via a combination of hardware and software. RSIL provides insight into the electrical interactions between a representative radioisotope power generator, its associated control schemes, and realistic electric system loads. The first phase of integration testing included the following spacecraft bus configurations: capacitive, battery, and supercapacitor. A load profile, created based on data from several missions, tested the RPS and RSIL ability to maintain operation during load demands above and below the power provided by the RPS. The integration testing also confirmed the DCC's ability to disconnect from the spacecraft when the bus voltage dipped below 22 V or exceeded 36 V. Once operation was verified with the DASCS, the tests were repeated with actual operating ASC's. The goal of this integration testing was to verify operation of the DCC when connected to a spacecraft and to verify the functionality of the newly designed RSIL. The results of these tests are presented in this paper.

  17. Feasibility study of a 110 watt per kilogram lightweight solar array system

    NASA Technical Reports Server (NTRS)

    Shepard, N. F.; Stahle, C. V.; Schneider, A.; Hanson, K. L.

    1972-01-01

    An investigation of the feasibility of a solar array panel subsystem which will produce 10,000 watts of electrical output at 1 A.U. with an overall beginning-of-life power-to-weight ratio of at least 110 watt/kg is reported. A description of the current baseline configuration which meets these requirements is presented. A parametric analysis of the single boom, two blanket planar solar array system was performed to arrive at the optimum system aspect ratio. A novel concept for the stiffening of a lightweight solar array by canting the solar cell blankets at a small angle to take advantage of the inherent in-plane stiffness to increase the symmetric out-of-plane frequency is introduced along with a preliminary analysis of the stiffening effect. A comparison of welded and soldered solar cell interconnections leads to the conclusion that welding is required on this ultralightweight solar array. The use of a boron/aluminum composite material in a BI-STEM type deployable boom is investigated as a possible advancement in the state-of-the-art.

  18. Advanced Stirling Convertor Dual Convertor Controller Testing at NASA Glenn Research Center in the Radioisotope Power Systems System Integration Laboratory

    NASA Technical Reports Server (NTRS)

    Dugala, Gina M.; Taylor, Linda M.; Bell, Mark E.; Dolce, James L.; Fraeman, Martin; Frankford, David P.

    2015-01-01

    NASA Glenn Research Center developed a nonnuclear representation of a Radioisotope Power System (RPS) consisting of a pair of Advanced Stirling Convertors (ASCs), Dual Convertor Controller (DCC) EMs (engineering models) 2 and 3, and associated support equipment, which were tested in the Radioisotope Power Systems System Integration Laboratory (RSIL). The DCC was designed by the Johns Hopkins University Applied Physics Laboratory (JHU/APL) to actively control a pair of ASCs. The first phase of testing included a Dual Advanced Stirling Convertor Simulator (DASCS), which was developed by JHU/APL and simulates the operation and electrical behavior of a pair of ASCs in real time via a combination of hardware and software. RSIL provides insight into the electrical interactions between a representative radioisotope power generator, its associated control schemes, and realistic electric system loads. The first phase of integration testing included the following spacecraft bus configurations: capacitive, battery, and super-capacitor. A load profile, created based on data from several missions, tested the RPS's and RSIL's ability to maintain operation during load demands above and below the power provided by the RPS. The integration testing also confirmed the DCC's ability to disconnect from the spacecraft when the bus voltage dipped below 22 volts or exceeded 36 volts. Once operation was verified with the DASCS, the tests were repeated with actual operating ASCs. The goal of this integration testing was to verify operation of the DCC when connected to a spacecraft and to verify the functionality of the newly designed RSIL. The results of these tests are presented in this paper.

  19. Modular Stirling Radioisotope Power System (SRPS) using an advanced heat source

    NASA Astrophysics Data System (ADS)

    Moul, David S.

    2001-02-01

    The advanced Stirling engine/alternator developed by Stirling Technology Company has potential for a wide range of space applications, at an efficiency comparable to solar cells and triple that of thermoelectric elements. However, the unique design of the Stirling engine requires a concentrated heat input in an annular band which would be optimized with an advanced heat source design. The concentrated heat rejection area of the Stirling engine would also be optimized with the use of a Capillary Pumped Loop to transport the waste heat from the engine. This advanced concept will explore using a Capillary Pumped Loop to transport the waste heat to the mission spacecraft for operational heating. Use of these advanced techniques will allow a specific power approaching 8 We/kg, compared to 5 We for a conventional RTG. .

  20. Technology demonstration of a free-piston stirling advanced radioisotope space power system

    NASA Astrophysics Data System (ADS)

    White, Maurice A.; Qiu, Songgang; Olan, Ronald W.; Erbeznik, Raymond M.

    1999-01-01

    Free-piston Stirling convertors (Stirling engine with integral linear alternator) are a mature technology with demonstrated long-life, maintenance-free, degradation-free operation exceeding 46,000 hours (5+ years) on one unit. Tens of thousands of hours have been accumulated on numerous systems in beta trials, plus more than 8 million flexure-hours (900 flexure-years) on the most critical component (flexure bearings), all with no failures when operated within specifications. Vibration is a key concern for Stirling convertors in space. Recent tests have demonstrated a factor of 50 reduction in vibration, relative to a single convertor, by coupling two convertors mechanically and electrically. Even though the measured vibration level is below Jet Propulsion Laboratory (JPL) specified vibration objectives, demonstration of an additional factor of 10 vibration reduction is pending with an active vibration reduction system. Stirling cycle efficiency is well established. A four-convertor 150-W(e) end of mission (EOM) power system for deep space missions is projected to require only three general purpose heat source (GPHS) modules with conservative Inconel 718 heater heads, leaving significant efficiency improvement potential when used with higher temperature materials. Even in the unlikely scenario of one inoperative convertor, the other three convertors ramp up to provide full output. A two-convertor demonstration system, representative of one-half of a 150-W(e) power system, is described in this paper and scheduled to become operational in December 1998.

  1. Radioisotope Stirling Engine Powered Airship for Low Altitude Operation on Venus

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.

    2012-01-01

    The feasibility of a Stirling engine powered airship for the near surface exploration of Venus was evaluated. The heat source for the Stirling engine was limited to 10 general purpose heat source (GPHS) blocks. The baseline airship utilized hydrogen as the lifting gas and the electronics and payload were enclosed in a cooled insulated pressure vessel to maintain the internal temperature at 320 K and 1 Bar pressure. The propulsion system consisted of an electric motor driving a propeller. An analysis was set up to size the airship that could operate near the Venus surface based on the available thermal power. The atmospheric conditions on Venus were modeled and used in the analysis. The analysis was an iterative process between sizing the airship to carry a specified payload and the power required to operate the electronics, payload and cooling system as well as provide power to the propulsion system to overcome the drag on the airship. A baseline configuration was determined that could meet the power requirements and operate near the Venus surface. From this baseline design additional trades were made to see how other factors affected the design such as the internal temperature of the payload chamber and the flight altitude. In addition other lifting methods were evaluated such as an evacuated chamber, heated atmospheric gas and augmented heated lifting gas. However none of these methods proved viable.

  2. Epoxy Adhesives for Stator Magnet Assembly in Stirling Radioisotope Generators (SRG)

    NASA Technical Reports Server (NTRS)

    Cater, George M.

    2004-01-01

    As NASA seeks to fulfill its goals of exploration and understanding through missions planned to visit the moons of Saturn and beyond, a number of challenges arise from the idea of deep space flight. One of the first problems associated with deep space travel is electrical power production for systems on the spacecraft. Conventional methods such as solar power are not practical because efficiency decreases substantially as the craft moves away from the Sun. The criterion for power generation during deep space missions are very specific, the main points requiring high reliability, low mass, minimal vibration and a long lifespan. A Stirling generator, although fairly old in concept, is considered to be a potential solution for electrical power generation for deep space flight. A Stirling generator works on the same electromagnetic principles of a standard generator, using the linear motion of the alternator through the stationary stator which produces electric induction. The motion of the alternator, however, is produced by the heating and cooling dynamics of pressurized gases. Essentially heating one end and cooling another of a contained gas will cause a periodic expansion and compression of the gas from one side to the other, which a displacer translates into linear mechanical motion. NASA needs to confirm that the materials used in the generator will be able to withstand the rigors of space and the life expectancy of the mission. I am working on the verification of the epoxy adhesives used to bond magnets to the steel lamination stack to complete the stator; in terms of in-service performance and durability under various space environments. Understanding the proper curing conditions, high temperature properties, and degassing problems as well as production difficulties are crucial to the long term success of the generator. system and steel substrate used in the stator. To optimize the curing conditions of the epoxies, modulated differential scanning calorimetry

  3. Utilizing Radioisotope Power System Waste Heat for Spacecraft Thermal Management

    NASA Technical Reports Server (NTRS)

    Pantano, David R.; Dottore, Frank; Geng, Steven M.; Schrieber, Jeffrey G.; Tobery, E. Wayne; Palko, Joseph L.

    2005-01-01

    One of the advantages of using a Radioisotope Power System (RPS) for deep space or planetary surface missions is the readily available waste heat, which can be used to maintain electronic components within a controlled temperature range, to warm propulsion tanks and mobility actuators, and to gasify liquid propellants. Previous missions using Radioisotope Thermoelectric Generators (RTGs) dissipated a very large quantity of waste heat due to the relatively low efficiency of the thermoelectric conversion technology. The next generation RPSs, such as the 110-watt Stirling Radioisotope Generator (SRG110) will have much higher conversion efficiencies than their predecessors and therefore may require alternate approaches to transferring waste heat to the spacecraft. RTGs, with efficiencies of approx. 6 to 7% and 200 C housing surface temperatures, would need to use large and heavy radiator heat exchangers to transfer the waste heat to the internal spacecraft components. At the same time, sensitive spacecraft instruments must be shielded from the thermal radiation by using the heat exchangers or additional shields. The SRG110, with an efficiency around 22% and 50 C nominal housing surface temperature, can use the available waste heat more efficiently by more direct heat transfer methods such as heat pipes, thermal straps, or fluid loops. The lower temperatures allow the SRG110 much more flexibility to the spacecraft designers in configuring the generator without concern of overheating nearby scientific instruments, thereby eliminating the need for thermal shields. This paper will investigate using a high efficiency SRG110 for spacecraft thermal management and outline potential methods in several conceptual missions (Lunar Rover, Mars Rover, and Titan Lander) to illustrate the advantages with regard to ease of assembly, less complex interfaces, and overall mass savings.

  4. Radioisotope Power System Pool Concept

    NASA Technical Reports Server (NTRS)

    Rusick, Jeffrey J.; Bolotin, Gary S.

    2015-01-01

    Advanced Radioisotope Power Systems (RPS) for NASA deep space science missions have historically used static thermoelectric-based designs because they are highly reliable, and their radioisotope heat sources can be passively cooled throughout the mission life cycle. Recently, a significant effort to develop a dynamic RPS, the Advanced Stirling Radioisotope Generator (ASRG), was conducted by NASA and the Department of Energy, because Stirling based designs offer energy conversion efficiencies four times higher than heritage thermoelectric designs; and the efficiency would proportionately reduce the amount of radioisotope fuel needed for the same power output. However, the long term reliability of a Stirling based design is a concern compared to thermoelectric designs, because for certain Stirling system architectures the radioisotope heat sources must be actively cooled via the dynamic operation of Stirling converters throughout the mission life cycle. To address this reliability concern, a new dynamic Stirling cycle RPS architecture is proposed called the RPS Pool Concept.

  5. Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head

    NASA Astrophysics Data System (ADS)

    Krause, David L.; Kantzos, Pete T.

    2006-01-01

    For proposed long-duration NASA Space Science missions, the Department of Energy, Lockheed Martin, Infinia Corporation, and NASA Glenn Research Center are developing a high-efficiency, 110-watt Stirling Radioisotope Generator (SRG110). A structurally significant limit state for the SRG110 heater head component is creep deformation induced at high material temperature and low stress level. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and a wealth of creep data is available for the Inconel 718 material of construction. However, the specified atypical thin heater head material is fine-grained with a heat treatment that limits precipitate growth, and little creep property data for this microstructure is available in the literature. In addition, the geometry and loading conditions apply a multiaxial stress state on the component, far from the conditions of uniaxial testing. For these reasons, an extensive experimental investigation is ongoing to aid in accurately assessing the durability of the SRG110 heater head. This investigation supplements uniaxial creep testing with pneumatic testing of heater head-like pressure vessels at design temperature with stress levels ranging from approximately the design stress to several times that. This paper presents experimental results, post-test microstructural analyses, and conclusions for four higher-stress, accelerated life tests. Analysts are using these results to calibrate deterministic and probabilistic analytical creep models of the SRG110 heater head.

  6. Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head

    SciTech Connect

    Krause, David L.; Kantzos, Pete T.

    2006-01-20

    For proposed long-duration NASA Space Science missions, the Department of Energy, Lockheed Martin, Infinia Corporation, and NASA Glenn Research Center are developing a high-efficiency, 110-watt Stirling Radioisotope Generator (SRG110). A structurally significant limit state for the SRG110 heater head component is creep deformation induced at high material temperature and low stress level. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and a wealth of creep data is available for the Inconel 718 material of construction. However, the specified atypical thin heater head material is fine-grained with a heat treatment that limits precipitate growth, and little creep property data for this microstructure is available in the literature. In addition, the geometry and loading conditions apply a multiaxial stress state on the component, far from the conditions of uniaxial testing. For these reasons, an extensive experimental investigation is ongoing to aid in accurately assessing the durability of the SRG110 heater head. This investigation supplements uniaxial creep testing with pneumatic testing of heater head-like pressure vessels at design temperature with stress levels ranging from approximately the design stress to several times that. This paper presents experimental results, post-test microstructural analyses, and conclusions for four higher-stress, accelerated life tests. Analysts are using these results to calibrate deterministic and probabilistic analytical creep models of the SRG110 heater head.

  7. Utilizing Radioisotope Power System Waste Heat for Spacecraft Thermal Management

    NASA Technical Reports Server (NTRS)

    Pantano, David R.; Dottore, Frank; Tobery, E. Wayne; Geng, Steven M.; Schreiber, Jeffrey G.; Palko, Joseph L.

    2005-01-01

    An advantage of using a Radioisotope Power System (RPS) for deep space or planetary surface missions is the readily available waste heat, which can be used for a number of beneficial purposes including: maintaining electronic components within a controlled temperature range, warming propulsion tanks and mobility actuators, and maintaining liquid propellants above their freezing temperature. Previous missions using Radioisotope Thermoelectric Generators (RTGs) dissipated large quantities of waste heat due to the low efficiency of the thermoelectric conversion technology. The next generation RPSs, such as the 110-Watt Stirling Radioisotope Generator (SRG110) will have higher conversion efficiencies, thereby rejecting less waste heat at a lower temperature and may require alternate approaches to transferring waste heat to the spacecraft. RTGs, with efficiencies of 6 to 7 percent, reject their waste heat at the relatively high heat rejection temperature of 200 C. This is an advantage when rejecting heat to space; however, transferring heat to the internal spacecraft components requires a large and heavy radiator heat exchanger. At the same time, sensitive spacecraft instruments must be shielded from the thermal radiation of the RTG. The SRG110, with an efficiency around 22 percent and 50 C nominal housing surface temperature, can readily transfer the available waste heat directly via heat pipes, thermal straps, or fluid loops. The lower temperatures associated with the SRG110 avoid the chances of overheating other scientific components, eliminating the need for thermal shields. This provides the spacecraft designers more flexibility when locating the generator for a specific mission. A common misconception with high-efficiency systems is that there is not enough waste heat for spacecraft thermal management. This paper will dispel this misconception and investigate the use of a high-efficiency SRG110 for spacecraft thermal management and outline potential methods of

  8. Using SpaceClaim/TD Direct for Modeling Components with Complex Geometries for the Thermal Desktop-Based Advanced Stirling Radioisotope Generator Model

    NASA Technical Reports Server (NTRS)

    Fabanich, William

    2014-01-01

    SpaceClaim/TD Direct has been used extensively in the development of the Advanced Stirling Radioisotope Generator (ASRG) thermal model. This paper outlines the workflow for that aspect of the task and includes proposed best practices and lessons learned. The ASRG thermal model was developed to predict component temperatures and power output and to provide insight into the prime contractors thermal modeling efforts. The insulation blocks, heat collectors, and cold side adapter flanges (CSAFs) were modeled with this approach. The model was constructed using mostly TD finite difference (FD) surfaces solids. However, some complex geometry could not be reproduced with TD primitives while maintaining the desired degree of geometric fidelity. Using SpaceClaim permitted the import of original CAD files and enabled the defeaturing repair of those geometries. TD Direct (a SpaceClaim add-on from CRTech) adds features that allowed the mark-up of that geometry. These so-called mark-ups control how finite element (FE) meshes were generated and allowed the tagging of features (e.g. edges, solids, surfaces). These tags represent parameters that include: submodels, material properties, material orienters, optical properties, and radiation analysis groups. TD aliases were used for most tags to allow analysis to be performed with a variety of parameter values. Domain-tags were also attached to individual and groups of surfaces and solids to allow them to be used later within TD to populate objects like, for example, heaters and contactors. These tools allow the user to make changes to the geometry in SpaceClaim and then easily synchronize the mesh in TD without having to redefine these objects each time as one would if using TD Mesher.The use of SpaceClaim/TD Direct has helped simplify the process for importing existing geometries and in the creation of high fidelity FE meshes to represent complex parts. It has also saved time and effort in the subsequent analysis.

  9. Using SpaceClaimTD Direct for Modeling Components with Complex Geometries for the Thermal Desktop-Based Advanced Stirling Radioisotope Generator Model

    NASA Technical Reports Server (NTRS)

    Fabanich, William A., Jr.

    2014-01-01

    SpaceClaim/TD Direct has been used extensively in the development of the Advanced Stirling Radioisotope Generator (ASRG) thermal model. This paper outlines the workflow for that aspect of the task and includes proposed best practices and lessons learned. The ASRG thermal model was developed to predict component temperatures and power output and to provide insight into the prime contractor's thermal modeling efforts. The insulation blocks, heat collectors, and cold side adapter flanges (CSAFs) were modeled with this approach. The model was constructed using mostly TD finite difference (FD) surfaces/solids. However, some complex geometry could not be reproduced with TD primitives while maintaining the desired degree of geometric fidelity. Using SpaceClaim permitted the import of original CAD files and enabled the defeaturing/repair of those geometries. TD Direct (a SpaceClaim add-on from CRTech) adds features that allowed the "mark-up" of that geometry. These so-called "mark-ups" control how finite element (FE) meshes are to be generated through the "tagging" of features (e.g. edges, solids, surfaces). These tags represent parameters that include: submodels, material properties, material orienters, optical properties, and radiation analysis groups. TD aliases were used for most tags to allow analysis to be performed with a variety of parameter values. "Domain-tags" were also attached to individual and groups of surfaces and solids to allow them to be used later within TD to populate objects like, for example, heaters and contactors. These tools allow the user to make changes to the geometry in SpaceClaim and then easily synchronize the mesh in TD without having to redefine the objects each time as one would if using TDMesher. The use of SpaceClaim/TD Direct helps simplify the process for importing existing geometries and in the creation of high fidelity FE meshes to represent complex parts. It also saves time and effort in the subsequent analysis.

  10. Stirling to Flight Initiative

    NASA Technical Reports Server (NTRS)

    Hibbard, Kenneth E.; Mason, Lee S.; Ndu, Obi; Smith, Clayton; Withrow, James P.

    2016-01-01

    NASA has a consistent need for radioisotope power systems (RPS) to enable robotic scientific missions for planetary exploration that has been present for over four decades and will continue into the foreseeable future, as documented in the most recent Planetary Science Decadal Study Report. As RPS have evolved throughout the years, there has also grown a desire for more efficient power systems, allowing NASA to serve as good stewards of the limited plutonium-238 (238Pu), while also supporting the ever-present need to minimize mass and potential impacts to the desired science measurements. In fact, the recent Nuclear Power Assessment Study (NPAS) released in April 2015 resulted in several key conclusion regarding RPS, including affirmation that RPS will be necessary well into the 2030s (at least) and that 238Pu is indeed a precious resource requiring efficient utilization and preservation. Stirling Radioisotope Generators (SRGs) combine a Stirling cycle engine powered by a radioisotope heater unit into a single generator system. Stirling engine technology has been under development at NASA Glenn Research Center (GRC) in partnership with the Department of Energy (DOE) since the 1970's. The most recent design, the 238Pu-fueled Advanced Stirling Radioisotope Generator (ASRG), was offered as part of the NASA Discovery 2010 Announcement of Opportunity (AO). The Step-2 selections for this AO included two ASRG-enabled concepts, the Titan Mare Explorer (TiME) and the Comet Hopper (CHopper), although the only non-nuclear concept, InSight, was ultimately chosen. The DOE's ASRG contract was terminated in 2013. Given that SRGs utilize significantly less 238Pu than traditional Radioisotope Thermoelectric Generators (RTGs) - approximately one quarter of the nuclear fuel, to produce similar electrical power output - they provide a technology worthy of consideration for meeting the aforementioned NASA objectives. NASA's RPS Program Office has recently investigated a new Stirling to

  11. Small Stirling Cycle Convertors

    NASA Astrophysics Data System (ADS)

    Penswick, L. Barry; Schreiber, Jeffery

    2005-02-01

    The Stirling convertor concept continues to be a viable potential candidate for various space power applications at electrical power levels ranging from greater than 100 KW to on the order of 10+watts. Various development efforts, both in the past and currently underway, have clearly demonstrated the potential for long operating life of this concept, its high efficiency in comparison to alternative power systems (>50% of Carnot based on electric power out to heat in), and its excellent specific power characteristics. A truly unique attribute of the Stirling convertor is the ability to maintain many of these same advantages at significantly lower electrical power levels (on the order of 1 watt and below). This provides the opportunity for a wider range of potential space power applications and the use of alternative heat sources operating at dramatically lower hot-end temperatures (about 250 °C vs. current values of about 650 °C). An overview of low-power Stirling convertors and related Stirling cooler technology is provided with an emphasis on assessing the technical maturity of this concept's key components at the low power level of interest. A conceptual design of a small, 1-watt (electrical output) Stirling convertor utilizing multiple Low Weight Radioisotope Heater Unit heat sources will be described. Key technical issues in the development of this power level Stirling convertor are discussed.

  12. Continuing Development for Free-Piston Stirling Space Power Systems

    NASA Astrophysics Data System (ADS)

    Peterson, Allen A.; Qiu, Songgang; Redinger, Darin L.; Augenblick, John E.; Petersen, Stephen L.

    2004-02-01

    Long-life radioisotope power generators based on free-piston Stirling engines are an energy-conversion solution for future space applications. The high efficiency of Stirling machines makes them more attractive than the thermoelectric generators currently used in space. Stirling Technology Company (STC) has been developing free-piston Stirling machines for over 30 years, and its family of Stirling generators is ideally suited for reliable, maintenance-free operation. This paper describes recent progress and status of the STC RemoteGen™ 55 W-class Stirling generator (RG-55), presents an overview of recent testing, and discusses how the technology demonstration design has evolved toward space-qualified hardware.

  13. Stirling Refrigerator

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru

    A Stirling cooler (refrigerator) was proposed in 1862 and the first Stirling cooler was put on market in 1955. Since then, many Stirling coolers have been developed and marketed as cryocoolers. Recently, Stirling cycle machines for heating and cooling at near-ambient temperatures between 173 and 400K, are recognized as promising candidates for alternative system which are more compatible with people and the Earth. The ideal cycles of Stirling cycle machine offer the highest thermal efficiencies and the working fluids do not cause serious environmental problems of ozone depletion and global warming. In this review, the basic thermodynamics of Stirling cycle are briefly described to quantify the attractive cycle performance. The fundamentals to realize actual Stirling coolers and heat pumps are introduced in detail. The current status of the Stirling cycle machine technologies is reviewed. Some machines have almost achieved the target performance. Also, duplex-Stirling-cycle and Vuilleumier-cycle machines and their performance are introduced.

  14. A Microfabricated Segmented-Involute-Foil Regenerator for Enhancing Reliability and Performance of Stirling Engines. Phase III Final Report for the Radioisotope Power Conversion Technology NRA

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir B.; Gedeon, David; Wood, Gary; McLean, Jeffrey

    2009-01-01

    Under Phase III of NASA Research Announcement contract NAS3-03124, a prototype nickel segmented-involute-foil regenerator was microfabricated and tested in a Sunpower Frequency-Test-Bed (FTB) Stirling convertor. The team for this effort consisted of Cleveland State University, Gedeon Associates, Sunpower Inc. and International Mezzo Technologies. Testing in the FTB convertor produced about the same efficiency as testing with the original random-fiber regenerator. But the high thermal conductivity of the prototype nickel regenerator was responsible for a significant performance degradation. An efficiency improvement (by a 1.04 factor, according to computer predictions) could have been achieved if the regenerator was made from a low-conductivity material. Also, the FTB convertor was not reoptimized to take full advantage of the microfabricated regenerator s low flow resistance; thus, the efficiency would likely have been even higher had the FTB been completely reoptimized. This report discusses the regenerator microfabrication process, testing of the regenerator in the Stirling FTB convertor, and the supporting analysis. Results of the pre-test computational fluid dynamics (CFD) modeling of the effects of the regenerator-test-configuration diffusers (located at each end of the regenerator) are included. The report also includes recommendations for further development of involute-foil regenerators from a higher-temperature material than nickel.

  15. Stirling Engine Controller

    NASA Technical Reports Server (NTRS)

    Blaze, Gina M.

    2004-01-01

    Stirling technology is being developed to replace RTG s (Radioisotope Thermoelectric Generators), more specifically a stirling convertor, which is a stirling engine coupled to a linear alternator. Over the past three decades, the stirling engine has been designed to perform different functions. Stirling convertors have been designed to decrease fuel consumption in automobiles. They have also been designed for terrestrial and space applications. Currently NASA Glenn is using the convertor for space based applications. A stiring converter is a better means of power for deep space mission and "dusty" mission, like the Mars Rovers, than solar panels because it is not affected by dust. Spirit and Opportunity, two Mars rovers currently navigating the planet, are losing their ability to generate electricity because dust is collecting on their solar panels. Opportunity is losing more energy because its robotic arm has a heater with a switch that can not be turned off. The heater is not needed at night, but yet still runs. This generates a greater loss of electricity and in turn diminishes the performance of the rover. The stirling cycle has the potential to provide very efficient conversion of heat energy to electric a1 energy, more so than RTG's. The stirling engine converts the thermal energy produced by the decaying radioisotope to mechanical energy; the linear alternator converts this into electricity. convertor. Since the early 1990's tests have been performed to maximize the efficiency of the stirling converter. Many months, even years, are dedicated to preparing and performing tests. Currently, two stirling convertors #'s 13 and 14, which were developed by Stirling Technology Company, are on an extended operation test. As of June 7th, the two convertors reached 7,500 hours each of operation. Before the convertors could run unattended, many safety precautions had to be examined. So, special instrumentation and circuits were developed to detect off nominal conditions

  16. Stirling engines

    SciTech Connect

    Reader, G.T.; Hooper

    1983-01-01

    The Stirling engine was invented by a Scottish clergyman in 1816, but fell into disuse with the coming of the diesel engine. Advances in materials science and the energy crisis have made a hot air engine economically attractive. Explanations are full and understandable. Includes coverage of the underlying thermodynamics and an interesting historical section. Topics include: Introduction to Stirling engine technology, Theoretical concepts--practical realities, Analysis, simulation and design, Practical aspects, Some alternative energy sources, Present research and development, Stirling engine literature.

  17. Advanced Stirling Convertor Testing at GRC

    NASA Technical Reports Server (NTRS)

    Schifer, Nick; Oriti, Salvatore M.

    2013-01-01

    NASA Glenn Research Center (GRC) has been supporting development of the Advanced Stirling Radioisotope Generator (ASRG) since 2006. A key element of the ASRG project is providing life, reliability, and performance testing of the Advanced Stirling Convertor (ASC). The latest version of the ASC, deemed ASC-E3, is of a design identical to the forthcoming flight convertors. The first pair of ASC-E3 units was delivered in December 2012. GRC has begun the process of adding these units to the catalog of ongoing Stirling convertor operation. This process includes performance verification, which examines the data from various tests to validate the convertors performance to the product specification.

  18. Stirling engines

    SciTech Connect

    Walker, G.

    1980-01-01

    Stirling engines exist in a bewildering array of mechanical arrangements. This book attempts to describe and classify the systems in a rational way, to explain the intricacies of the cycle, and to present a large amount of detailed information related to Stirling engines such as design, heat exchangers, working fluids, operation and performance, control equipment, recently developed engines, and current and proposed uses. (LCL)

  19. Optimized Heat Pipe Backup Cooling System Tested with a Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Schwendeman, Carl L.; Schifer, Nicholas A.; Anderson, William G.

    2016-01-01

    Advanced Stirling Radioisotope Generator (ASRG) is an attractive energy system for select space missions, and with the addition of a VCHP, it becomes even more versatile. The ASRG is powered through thermal energy from decaying radioisotopes acting as General Purpose Heat Sources (GPHS). A Stirling engine converts the thermal energy to electrical energy and cools the GPHS [2]. The Stirling convertor must operate continuously to maintain acceptable temperatures of the GPHS and protect their cladding. The addition of alkali metal VCHP allows the Stirling to cycle on and off during a mission and can be used as a backup cooling system. The benefits of being able to turn the Stirling off are: allowing for a restart of the Stirling and reducing vibrations for sensitive measurements. The VCHP addition should also increase the efficiency of the Stirling by providing a uniform temperature distribution at the heat transfer interface into the heater head.

  20. Practical bellows seals for Stirling engines

    SciTech Connect

    White, M.A.; Emigh, S.G.; Riggle, P.

    1987-01-01

    Rod seals, and to a lesser extent piston seals, are the primary impediments to long life and high reliability for kinematic Stirling engines. Hermetic metal bellows have been successfully demonstrated for 6.9 years and 4 x 10/sup 9/ cycles in a free-piston Stirling engine. A totally different radioisotope fueled free-piston Stirling engine with a flexing metal diaphragm was still operating at last report after more than 12 years and 3 x 10/sup 10/ cycles. A concept for implementing logn life bellows to function as rod seals and piston seals in kinematic Stirling engines has been developed and is presented for the first time in this paper.

  1. Technology Assessment of Doe's 55-we Stirling Technology Demonstrator Convector (TDC)

    NASA Technical Reports Server (NTRS)

    Furlong, Richard; Shaltens, Richard

    2000-01-01

    The Department of Energy (DOE), Germantown, Maryland and the NASA Glenn Research Center (GRC), Cleveland, Ohio are developing a Stirling Convertor for an advanced radioisotope power system as a potential power source for spacecraft on-board electric power for NASA deep space science missions. The Stirling Convertor is being evaluated as an alternative high efficiency power source to replace Radioisotope Thermoelectric Generators (RTGs). Stirling Technology Company (STC), Kennewick, Washington, is developing the highly efficient, long life 55-We free-piston Stirling Convertor known as the Technology Demonstrator Convertor (TDC) under contract to DOE. GRC provides Stirling technology expertise under a Space Act Agreement with the DOE. Lockheed Martin Astronautics (LMA), Valley Forge, Pennsylvania is the current power system integrator for the Advanced Radioisotope Power System (ARPS) Project for the DOE. JPL is responsible for the Outer Planets/Solar Probe Project for NASA.

  2. Extended Operation of Stirling Convertors

    NASA Technical Reports Server (NTRS)

    Roth, Mary Ellen; Schreiber, Jeffery G.; Pepper, Stephen V.

    2004-01-01

    A high-efficiency 110 W Stirling Radioisotope Generator 110 (SRG110) is being developed for potential NASA exploration missions. The SRG system efficiency is greater than 20%, making it an attractive candidate power system for deep space missions and unmanned rovers. The Department of Energy SRG110 Project team consists of the System Integrator, Lockheed Martin (LM), Stirling Technology Company (STC), and NASA Glenn Research Center (GRC). One of the GRC roles is to provide Independent Verification and Validation of the Stirling TDC s. At the request of LM, a part of this effort includes the Extended Operation of the TDC s in the dynamically balanced dual-opposed configuration. Performance data of Stirling Convertors over time is required to demonstrate that an SRG110 can meet long-duration mission requirements. A test plan and test system were developed to evaluate TDC s #13 and #14 steady-state performance for a minimum of 5000 hours. Hardware, software and TDC preparation processes were developed to support this test and insure safe, round-the-clock operation of the TDC s. This paper will discuss the design and development, and status of the Extended Operation Test.

  3. Advanced Stirling Convertor (ASC-E2) Characterization Testing

    NASA Technical Reports Server (NTRS)

    Williams, Zachary D.; Oriti, Salvatore M.

    2012-01-01

    Testing has been conducted on Advanced Stirling Convertor (ASC-E2) convertors at NASA Glenn Research Center in support of the Advanced Stirling Radioisotope Generator (ASRG) Project. This testing has been conducted to understand sensitivities of convertor parameters due to environmental and operational changes during operation of the ASRG in missions to space. This paper summarizes test results and explains in terms of operation of the ASRG during space missions.

  4. Advanced Stirling Convertor (ASC-E2) Characterization Testing

    NASA Technical Reports Server (NTRS)

    Williams, Zachary D.; Oriti, Salvatore M.

    2012-01-01

    Testing has been conducted on Advanced Stirling Convertors (ASCs)-E2 at NASA Glenn Research Center in support of the Advanced Stirling Radioisotope Generator (ASRG) project. This testing has been conducted to understand sensitivities of convertor parameters due to environmental and operational changes during operation of the ASRG in missions to space. This paper summarizes test results and explains the operation of the ASRG during space missions

  5. Overview of Stirling Technology Research at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.; Schifer, Nicholas A.; Williams, Zachary D.; Metscher, Jonathan F.

    2015-01-01

    Stirling Radioisotope Power Systems (RPS) are under development to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove using less than a quarter of the plutonium the currently available RPS uses to produce about the same power. Glenn Research Center's (GRC's) newly formulated Stirling Cycle Technology Development Project (SCTDP) continues development of Stirling-based systems and subsystems, which include a flight-like generator and related housing assembly, controller, and convertors. The project also develops less mature technologies under Stirling Technology Research, with a focus on demonstration in representative environments to increase the technology readiness level (TRL). Matured technologies are evaluated for selection in future generator designs. Stirling Technology Research tasks focus on a wide variety of objectives, including increasing temperature capability to enable new environments, reducing generator mass and/or size, improving reliability or system fault tolerance, and developing alternative designs. The task objectives and status are summarized.

  6. Impact testing of a Stirling convertor's linear alternator

    NASA Astrophysics Data System (ADS)

    Suárez, Vicente J.; Goodnight, Thomas W.; Hughes, William O.; Samorezov, Sergey

    2002-01-01

    The U.S. Department of Energy (DOE), in conjunction with NASA John H. Glenn Research Center and Stirling Technology Company, are currently developing a Stirling convertor for a Stirling Radioisotope Generator (SRG). NASA Headquarters and DOE have identified the SRG for potential use as an advanced spacecraft power system for future NASA deep-space and Mars surface missions. Low-level dynamic impact tests were conducted at NASA Glenn Research Center's Structural Dynamics Laboratory as part of the development of this technology. The purpose of this test was to identify dynamic structural characteristics of the Stirling Technology Demonstration Convertor (TDC). This paper addresses the test setup, procedure and results of the impact testing conducted on the Stirling TDC in May 2001. .

  7. Impact Testing of a Stirling Converter's Linear Alternator

    NASA Technical Reports Server (NTRS)

    Suarez, Vicente J.; Goodnight, Thomas W.; Hughes, William O.; Samorezov, Sergey

    2002-01-01

    The U.S. Department of Energy (DOE), in conjunction with the NASA John H. Glenn Research Center and Stirling Technology Company, are currently developing a Stirling convertor for a Stirling Radioisotope Generator (SRG). NASA Headquarters and DOE have identified the SRG for potential use as an advanced spacecraft power system for future NASA deep-space and Mars surface missions. Low-level dynamic impact tests were conducted at NASA Glenn Research Center's Structural Dynamics Laboratory as part of the development of this technology. The purpose of this test was to identify dynamic structural characteristics of the Stirling Technology Demonstration Convertor (TDC). This paper addresses the test setup, procedure, and results of the impact testing conducted on the Stirling TDC in May 2001.

  8. Overview of Stirling Technology Research at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.; Schifer, Nicholas A.; Williams, Zachary D.; Metscher, Jonathan F.

    2016-01-01

    Stirling Radioisotope Power Systems (RPSs) are under development to provide power on future space science missions where robotic spacecraft will orbit, fly by, land, or rove using less than a quarter of the plutonium the currently available RPS uses to produce about the same power. NASA Glenn Research Center's newly formulated Stirling Cycle Technology Development Project (SCTDP) continues development of Stirling-based systems and subsystems, which include a flight-like generator and related housing assembly, controller, and convertors. The project also develops less mature technologies under Stirling Technology Research, with a focus on demonstration in representative environments to increase the technology readiness level (TRL). Matured technologies are evaluated for selection in future generator designs. Stirling Technology Research tasks focus on a wide variety of objectives, including increasing temperature capability to enable new environments, reducing generator mass and/or size, improving reliability and system fault tolerance, and developing alternative designs. The task objectives and status are summarized.

  9. Stirling Convertor Extended Operation Testing and Data Analysis at GRC

    NASA Technical Reports Server (NTRS)

    Cornell, Peggy A.; Lewandowski, Edward J.; Oriti, Salvatore M.; Wilson, Scott D.

    2009-01-01

    This paper focuses on extended operation testing and data analysis of free-piston Stirling convertors at the NASA Glenn Research Center (GRC). Extended operation testing is essential to the development of radioisotope power systems and their potential use for long duration missions. To document the reliability of the convertors, regular monitoring and analysis of the extended operation data is particularly valuable; allowing us to better understand and quantity the long life characteristics of the convertors. Further, investigation and comparison of the extended operation data to baseline performance data provides us an opportunity for understanding system behavior should any off-nominal performance occur. GRC currently has 14 Stirling convertors under 24-hour unattended extended operation testing, including two operating the Advanced Stirling Radioisotope Generator Engineering Unit (ASRG-EU). 10 of the 14 Stirling convertors at GRC are the Advanced Stirling Convertors (ASC) developed by Sunpower, Incorporated. These are highly efficient (up to > 33.5% conversion efficiency), low mass convertors that have evolved through technologically progressive convertor builds. The remaining four convertors at GRC are Technology Demonstration Convertors (TDC) from Infinia Corporation. They have achieved> 27% conversion efficiency and have accumulated over 178,000 of the total 250,622 hours of extended operation currently at GRC. A synopsis of the Stirling convertor extended operation testing and data analysis at NASA GRC is presented in this paper, as well as how this testing has contributed to the Stirling convertor's progression toward flight.

  10. Assessment of Stirling Technology Has Provided Critical Data Leading Toward Flight Readiness of the Stirling Converter

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.

    2001-01-01

    The NASA Glenn Research Center is supporting the development of a Stirling converter with the Department of Energy (DOE, Germantown, Maryland) for an advanced Stirling Radioisotope Power System (SRPS) to provide spacecraft onboard electric power for NASA space science missions. A key technology assessment completed by Glenn and DOE has led to the SRPS being identified as a high-efficiency power source for such deep space missions as the Europa Orbiter and the Solar Probe. In addition, the Stirling system is now being considered for unmanned Mars rovers, especially where mission profiles may exclude the use of photovoltaic power systems, such as exploration at high Martian latitudes or for missions of long duration. The SRPS efficiency of over 20 percent will reduce the required amount of radioisotope by more than a factor of 3 in comparison to current radioisotope thermoelectric generators. This significantly reduces radioisotope cost, radiological inventory, and system cost, and it provides efficient use of scarce radioisotope resources. In support of this technology assessment, Glenn conducted a series of independent evaluations and tests to determine the technology readiness of a 55-We Stirling converter developed by Stirling Technology Company (Kennewick, Washington) and DOE. Key areas evaluated by Glenn included: 1) Radiation tolerance of materials; 2) Random vibration testing of the Stirling converter in Glenn's Structural Dynamics Lab to simulate operation in the launch environment; 3) Electromagnetic interference and compatibility (EMI/EMC) of the converter operating in Glenn's EMI lab; Independent failure modes, effects, and criticality analysis, and life and reliability 4. Independent failure modes, effects, and criticality analysis, and life and reliability assessment; and 5) SRPS cost estimate. The data from these evaluations were presented to NASA Headquarters and the Jet Propulsion Laboratory mission office by a joint industry/Government team

  11. NASA Radioisotope Power System Program - Technology and Flight Systems

    NASA Technical Reports Server (NTRS)

    Sutliff, Thomas J.; Dudzinski, Leonard A.

    2009-01-01

    NASA sometimes conducts robotic science missions to solar system destinations for which the most appropriate power source is derived from thermal-to-electrical energy conversion of nuclear decay of radioactive isotopes. Typically the use of a radioisotope power system (RPS) has been limited to medium and large-scale missions, with 26 U,S, missions having used radioisotope power since 1961. A research portfolio of ten selected technologies selected in 2003 has progressed to a point of maturity, such that one particular technology may he considered for future mission use: the Advanced Stirling Converter. The Advanced Stirling Radioisotope Generator is a new power system in development based on this Stirling cycle dynamic power conversion technology. This system may be made available for smaller, Discovery-class NASA science missions. To assess possible uses of this new capability, NASA solicited and funded nine study teams to investigate unique opportunities for exploration of potential destinations for small Discovery-class missions. The influence of the results of these studies and the ongoing development of the Advanced Stirling Radioisotope Generator system are discussed in the context of an integrated Radioisotope Power System program. Discussion of other and future technology investments and program opportunities are provided.

  12. Advanced Stirling Convertor (ASC) Technology Maturation

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Wilson, Scott; Collins, Josh; Wilson, Kyle

    2015-01-01

    The Advanced Stirling Convertor (ASC) development effort was initiated by NASA Glenn Research Center (GRC) with contractor Sunpower Inc. to develop high efficiency thermal-to-electric power conversion technology for NASA Radioisotope Power Systems. Early successful performance demonstrations led to the expansion of the project as well as adoption of the technology by the Department of Energy (DOE) and system integration contractor Lockheed Martin Space Systems Company as part of the Advanced Stirling Radioisotope Generator (ASRG) flight project. The ASRG integrates a pair of ASCs to convert the heat from a pair of General Purpose Heat Source (GPHS) modules into electrical power. The expanded NASA ASC effort included development of several generations of ASC prototypes or Engineering Units to help prepare the ASC technology and Sunpower for flight implementation. Sunpower later had two parallel contracts allowing the last of the NASA Engineering Units called ASC-E3 to serve as pathfinders for the ASC-F flight convertors being built for DOE. The ASC-E3 convertors utilized the ASC-F flight specifications and were built using the ASC-F design and process documentation. Shortly after the first ASC-F Pair achieved initial operation, due to budget constraints, the DOE ASRG flight development contract was terminated. NASA continues to invest in the development of Stirling RPS technology including continued production of the ASC-E3 convertors, seven of which have been delivered with one additional unit in production. Starting in FY2015, Stirling Convertor Technology Maturation has been reorganized as an element of the RPS Stirling Cycle Technology Development (SCTD) Project and long-term plans for continued Stirling technology advancement are in reformulation. This paper provides a status on the ASC project, an overview of advancements made in the design and production of the ASC at Sunpower, and a summary of acceptance tests, reliability tests, and tactical tests at NASA

  13. Advanced Stirling Convertor (ASC) Technology Maturation

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Wilson, Scott; Collins, Josh; Wilson, Kyle

    2016-01-01

    The Advanced Stirling Convertor (ASC) development effort was initiated by NASA Glenn Research Center with contractor Sunpower, Inc., to develop high-efficiency thermal-to-electric power conversion technology for NASA Radioisotope Power Systems (RPSs). Early successful performance demonstrations led to the expansion of the project as well as adoption of the technology by the Department of Energy (DOE) and system integration contractor Lockheed Martin Space Systems Company as part of the Advanced Stirling Radioisotope Generator (ASRG) flight project. The ASRG integrates a pair of ASCs to convert the heat from a pair of General Purpose Heat Source (GPHS) modules into electrical power. The expanded NASA ASC effort included development of several generations of ASC prototypes or engineering units to help prepare the ASC technology and Sunpower for flight implementation. Sunpower later had two parallel contracts allowing the last of the NASA engineering units called ASC-E3 to serve as pathfinders for the ASC-F flight convertors being built for DOE. The ASC-E3 convertors utilized the ASC-F flight specifications and were built using the ASC-F design and process documentation. Shortly after the first ASC-F pair achieved initial operation, due to budget constraints, the DOE ASRG flight development contract was terminated. NASA continues to invest in the development of Stirling RPS technology including continued production of the ASC-E3 convertors, seven of which have been delivered with one additional unit in production. Starting in fiscal year 2015, Stirling Convertor Technology Maturation has been reorganized as an element of the RPS Stirling Cycle Technology Development (SCTD) Project and long-term plans for continued Stirling technology advancement are in reformulation. This paper provides a status on the ASC project, an overview of advancements made in the design and production of the ASC at Sunpower, and a summary of acceptance tests, reliability tests, and tactical

  14. NASA GRC Stirling Technology Development Overview

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2003-01-01

    The Department of Energy, Lockheed Martin (LM), Stirling Technology Company, and NASA Glenn Research Center (GRC) are developing a high-efficiency Stirling Radioisotope Generator (SRG) for potential NASA Space Science missions. The SRG is being developed for multimission use, including providing spacecraft onboard electric power for NASA deep space missions and power for unmanned Mars rovers. NASA GRC is conducting an in- house supporting technology project to assist in developing the Stirling convertor for space qualification and mission implementation. Preparations are underway for a thermalhacuum system demonstration and unattended operation during endurance testing of the 55-We Technology Demonstration Convertors. Heater head life assessment efforts continue, including verification of the heater head brazing and heat treatment schedules and evaluation of any potential regenerator oxidation. Long-term magnet aging tests are continuing to characterize any possible aging in the strength or demagnetization resistance of the permanent magnets used in the linear alternator. Testing of the magnet/lamination epoxy bond for performance and lifetime characteristics is now underway. These efforts are expected to provide key inputs as the system integrator, LM, begins system development of the SRG. GRC is also developing advanced technology for Stirling convertors. Cleveland State University (CSU) is progressing toward a multi-dimensional Stirling computational fluid dynamics code, capable of modeling complete convertors. Validation efforts at both CSU and the University of Minnesota are complementing the code development. New efforts have been started this year on a lightweight convertor, advanced controllers, high-temperature materials, and an end-to-end system dynamics model. Performance and mass improvement goals have been established for second- and third-generation Stirling radioisotope power systems.

  15. NASA GRC Stirling Technology Development Overview

    NASA Astrophysics Data System (ADS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2003-01-01

    The Department of Energy, Lockheed Martin (LM), Stirling Technology Company, and NASA Glenn Research Center (GRC) are developing a high-efficiency Stirling Radioisotope Generator (SRG) for potential NASA Space Science missions. The SRG is being developed for multimission use, including providing spacecraft onboard electric power for NASA deep space missions and power for unmanned Mars rovers. NASA GRC is conducting an in-house supporting technology project to assist in developing the Stirling convertor for space qualification and mission implementation. Preparations are underway for a thermal/vacuum system demonstration and unattended operation during endurance testing of the 55-We Technology Demonstration Convertors. Heater head life assessment efforts continue, including verification of the heater head brazing and heat treatment schedules and evaluation of any potential regenerator oxidation. Long-term magnet aging tests are continuing to characterize any possible aging in the strength or demagnetization resistance of the permanent magnets used in the linear alternator. Testing of the magnet/lamination epoxy bond for performance and lifetime characteristics is now underway. These efforts are expected to provide key inputs as the system integrator, LM, begins system development of the SRG. GRC is also developing advanced technology for Stirling convertors. Cleveland State University (CSU) is progressing toward a multi-dimensional Stirling computational fluid dynamics code, capable of modeling complete convertors. Validation efforts at both CSU and the University of Minnesota are complementing the code development. New efforts have been started this year on a lightweight convertor, advanced controllers, high-temperature materials, and an end-to-end system dynamics model. Performance and mass improvement goals have been established for second- and third-generation Stirling radioisotope power systems.

  16. Advanced Technology Development for Stirling Convertors

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2004-01-01

    A high-efficiency Stirling Radioisotope Generator (SRG) for use on potential NASA Space Science missions is being developed by the Department of Energy, Lockheed Martin, Stirling Technology Company, and NASA Glenn Research Center (GRC). These missions may include providing spacecraft onboard electric power for deep space missions or power for unmanned Mars rovers. GRC is also developing advanced technology for Stirling convertors, aimed at substantially improving the specific power and efficiency of the convertor and the overall power system. Performance and mass improvement goals have been established for second- and thirdgeneration Stirling radioisotope power systems. Multiple efforts are underway to achieve these goals, both in-house at GRC and under various grants and contracts. The status and results to date for these efforts will be discussed in this paper. Cleveland State University (CSU) is developing a multi-dimensional Stirling computational fluid dynamics code, capable of modeling complete convertors. A 2-D version of the code is now operational, and validation efforts at both CSU and the University of Minnesota are complementing the code development. A screening of advanced superalloy, refractory metal alloy, and ceramic materials has been completed, and materials have been selected for creep and joining characterization as part of developing a high-temperature heater head. A breadboard characterization is underway for an advanced controller using power electronics for active power factor control with a goal of eliminating the heavy tuning capacitors that are typically needed to achieve near unity power factors. Key Stirling developments just initiated under recent NRA (NASA Research Announcement) awards will also be discussed. These include a lightweight convertor to be developed by Sunpower Inc. and an advanced microfabricated regenerator to be done by CSU.

  17. Stirling Convertor Fasteners Reliability Quantification

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin R.; Korovaichuk, Igor; Kovacevich, Tiodor; Schreiber, Jeffrey G.

    2006-01-01

    Onboard Radioisotope Power Systems (RPS) being developed for NASA s deep-space science and exploration missions require reliable operation for up to 14 years and beyond. Stirling power conversion is a candidate for use in an RPS because it offers a multifold increase in the conversion efficiency of heat to electric power and reduced inventory of radioactive material. Structural fasteners are responsible to maintain structural integrity of the Stirling power convertor, which is critical to ensure reliable performance during the entire mission. Design of fasteners involve variables related to the fabrication, manufacturing, behavior of fasteners and joining parts material, structural geometry of the joining components, size and spacing of fasteners, mission loads, boundary conditions, etc. These variables have inherent uncertainties, which need to be accounted for in the reliability assessment. This paper describes these uncertainties along with a methodology to quantify the reliability, and provides results of the analysis in terms of quantified reliability and sensitivity of Stirling power conversion reliability to the design variables. Quantification of the reliability includes both structural and functional aspects of the joining components. Based on the results, the paper also describes guidelines to improve the reliability and verification testing.

  18. Accomplishments in free-piston stirling tests at NASA GRC

    NASA Astrophysics Data System (ADS)

    Schreiber, Jeffrey G.; Skupinski, Robert C.

    2002-01-01

    A power system based on the Stirling Radioisotope Generator (SRG) has been identified for potential use on deep space missions, as well as for Mars rovers that may benefit from extended operation. The Department of Energy (DOE) has responsibility for developing the generator and the NASA Glenn Research Center (GRC) is supporting DOE in this effort. The generator is based on a free-piston Stirling power convertor that has been developed by the Stirling Technology Company (STC) under contract to DOE. The generator would be used as a high-efficiency alternative to the Radioisotope Thermoelectric Generators (RTGs) that have been used on many previous missions. The increased efficiency leads to a factor of 3 to 4 reduction in the inventory of plutonium required to heat the generator. GRC has been involved in the development of Stirling power conversion technology for over 25 years. The support provided to this project by GRC has many facets and draws upon the lab's scientists and engineers that have gained experience in applying their skills to the previous Stirling projects. This has created a staff with an understanding of the subtleties involved in applying their expertise to Stirling systems. Areas include materials, structures, tribology, controls, electromagnetic interference, permanent magnets, alternator analysis, structural dynamics, and cycle performance. One of the key areas of support to the project is in the performance testing of the free-piston Stirling convertors. Since these power convertors are the smallest, lowest power Stirling machines that have been tested at GRC, a new laboratory was equipped for this project. Procedures and test plans have been created, instrumentation and data systems developed, and Stirling convertors have been tested. This paper will describe the GRC test facility, the test procedures that are used, present some of the test results and outline plans for the future. .

  19. Vibration Testing of Stirling Power Convertors

    NASA Technical Reports Server (NTRS)

    Hughes, Bill; Goodnight, Thomas; McNelis, Mark E.; Suarez, Vicente J.; Schreiber, Jeff; Samorezov, Sergey

    2003-01-01

    to supply on- board electric spacecraft power for future NASA Deep-Space Missions, performing as an attractive alternative to Radioisotope Thermoelectric Generators (RTG). Usage of the Stirling technology is also being considered as the electric power source for future Mars rovers, whose mission profiles may exclude the use of photovoltaic power systems (such as exploring at high Martian latitudes or for missions of lengthy durations). GRC s Thermo-Mechanical Systems Branch (5490) provides Stirling technology expertise under a Space Act Agreement with the DOE. Additional vibration testing, by GRC s Structural Systems Dynamics Branch (7733, is planned to continue to demonstrate the Stirling power system s vibration capability as its technology and flight system designs progress.

  20. Summary of Stirling Convertor Testing at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    2006-01-01

    The NASA Glenn Research Center (GRC) has been testing free-piston Stirling convertors for potential use in radioisotope power systems. These convertors tend to be in the 35 to 80 W electric power output range. Tests at GRC have accumulated over 80,000 hr of operation. Test articles have been received from Infinia Corporation of Kennewick, Washington and from Sunpower of Athens, Ohio. Infinia designed and built the developmental Stirling Technology Demonstration Convertors (TDC) in addition to the more advanced Test Bed and Engineering Unit convertors. GRC has eight of the TDC's under test including two that operate in a thermal vacuum environment. Sunpower designed and developed the EE-35 and the Advanced Stirling Convertor (ASC). GRC has six of the EE- 35 s and is preparing for testing multiple ASC s. Free-piston Stirling convertors for radioisotope power systems make use of non-contacting operation that eliminates wear and is suited for long-term operation. Space missions with radioisotope power systems are often considered that extend from three to 14 years. One of the key capabilities of the GRC test facility is the ability to support continuous, unattended operation. Hardware, software, and procedures for preparing the test articles were developed to support these tests. These included the processing of the convertors for minimizing the contaminants in the working fluid, developing a helium charging system for filling and for gas sample analysis, and the development of new control software and a high-speed protection circuit to insure safe, round-the-clock operation. Performance data of Stirling convertors over time is required to demonstrate that a radioisotope power system is capable of providing reliable power for multi-year missions. This paper will discuss the status of Stirling convertor testing at GRC.

  1. Effect of structural mount dynamics on a pair of operating Stirling Convertors

    NASA Astrophysics Data System (ADS)

    Goodnight, Thomas W.; Suárez, Vicente J.; Hughes, William O.; Samorezov, Sergey

    2002-01-01

    The U.S. Department of Energy (DOE), in conjunction with NASA John H. Glenn Research Center and Stirling Technology Company, are currently developing a Stirling convertor for a Stirling Radioisotope Generator (SRG). NASA Headquarters and DOE have identified the SRG for potential use as an advanced spacecraft power system for future NASA deep-space and Mars surface missions. Low-level dynamic base-shake tests were conducted on a dynamic simulation of the structural mount for a pair of Operating Stirling Convertors. These tests were conducted at NASA Glenn Research Center's Structural Dynamics Laboratory as part of the development of this technology. The purpose of these tests was to identify the changes in transmissibility and the effect on structural dynamic response on a pair of operating Stirling Technology Demonstration Convertors (TDCs). This paper addresses the base-shake test, setup, procedure and results conducted on the Stirling TDC mount simulator in April 2001. .

  2. NASA's Radioisotope Power Systems Program Status

    NASA Technical Reports Server (NTRS)

    Dudzinski, Leonard A.; Hamley, John A.; McCallum, Peter W.; Sutliff, Thomas J.; Zakrajsek, June F.

    2013-01-01

    NASA's Radioisotope Power Systems (RPS) Program began formal implementation in December 2010. The RPS Program's goal is to make available RPS for the exploration of the solar system in environments where conventional solar or chemical power generation is impractical or impossible to meet mission needs. To meet this goal, the RPS Program manages investments in RPS system development and RPS technologies. The current keystone of the RPS Program is the development of the Advanced Stirling Radioisotope Generator (ASRG). This generator will be about four times more efficient than the more traditional thermoelectric generators, while providing a similar amount of power. This paper provides the status of the RPS Program and its related projects. Opportunities for RPS generator development and targeted research into RPS component performance enhancements, as well as constraints dealing with the supply of radioisotope fuel, are also discussed in the context of the next ten years of planetary science mission plans.

  3. Update on the NASA GRC Stirling Technology Development Project

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2000-01-01

    The Department of Energy, NASA Glenn Research Center (GRC), and Stirling Technology Company (STC) are developing a free-piston Stirling convertor for a Stirling radioisotope power system (SRPS) to provide spacecraft on-board electric power for NASA deep space missions. The SRPS has recently been identified for potential use on the Europa Orbiter and Solar Probe Space Science missions. Stirling is also now being considered for unmanned Mars rovers. NASA GRC is conducting an in-house project to assist in developing the Stirling convertor for readiness for space qualification and mission implementation. As part of this continuing effort, the Stirling convertor will be further characterized under launch environment random vibration testing, methods to reduce convertor electromagnetic interference (EMI) will be developed, and an independent performance verification will be completed. Convertor life assessment and permanent magnet aging characterization tasks are also underway. Substitute organic materials for the linear alternator and piston bearing coatings for use in a high radiation environment have been identified and have now been incorporated in Stirling convertors built by STC for GRC. Electromagnetic and thermal finite element analyses for the alternator are also being conducted. This paper discusses the recent results and status for this NASA GRC in-house project.

  4. The NASA Next Generation Stirling Technology Program Overview

    NASA Astrophysics Data System (ADS)

    Schreiber, J. G.; Shaltens, R. K.; Wong, W. A.

    2005-12-01

    NASAs Science Mission Directorate is developing the next generation Stirling technology for future Radioisotope Power Systems (RPS) for surface and deep space missions. The next generation Stirling convertor is one of two advanced power conversion technologies currently being developed for future NASA missions, and is capable of operating for both planetary atmospheres and deep space environments. The Stirling convertor (free-piston engine integrated with a linear alternator) produces about 90 We(ac) and has a specific power of about 90 We/kg. Operating conditions of Thot at 850 degree C and Trej at 90 degree C results in the Stirling convertor estimated efficiency of about 40 per cent. Using the next generation Stirling convertor in future RPS, the "system" specific power is estimated at 8 We/kg. The design lifetime is three years on the surface of Mars and fourteen years in deep space missions. Electrical power of about 160 We (BOM) is produced by two (2) free-piston Stirling convertors heated by two (2) General Purpose Heat Source (GPHS) modules. This development is being performed by Sunpower, Athens, OH with Pratt & Whitney, Rocketdyne, Canoga Park, CA under contract to Glenn Research Center (GRC), Cleveland, Ohio. GRC is guiding the independent testing and technology development for the next generation Stirling generator.

  5. NASA Multidimensional Stirling Convertor Code Developed

    NASA Technical Reports Server (NTRS)

    Tew, Roy C.; Thieme, Lanny G.

    2004-01-01

    A high-efficiency Stirling Radioisotope Generator (SRG) for use on potential NASA Space Science missions is being developed by the Department of Energy, Lockheed Martin, Stirling Technology Company, and the NASA Glenn Research Center. These missions may include providing spacecraft onboard electric power for deep space missions or power for unmanned Mars rovers. Glenn is also developing advanced technology for Stirling convertors, aimed at substantially improving the specific power and efficiency of the convertor and the overall power system. Performance and mass improvement goals have been established for second- and third-generation Stirling radioisotope power systems. Multiple efforts are underway to achieve these goals, both in house at Glenn and under various grants and contracts. These efforts include the development of a multidimensional Stirling computational fluid dynamics code, high-temperature materials, advanced controllers, an end-to-end system dynamics model, low-vibration techniques, advanced regenerators, and a lightweight convertor. Under a NASA grant, Cleveland State University (CSU) and its subcontractors, the University of Minnesota (UMN) and Gedeon Associates, have developed a twodimensional computer simulation of a CSUmod Stirling convertor. The CFD-ACE commercial software developed by CFD Research Corp. of Huntsville, Alabama, is being used. The CSUmod is a scaled version of the Stirling Technology Demonstrator Convertor (TDC), which was designed and fabricated by the Stirling Technology Company and is being tested by NASA. The schematic illustrates the structure of this model. Modeled are the fluid-flow and heat-transfer phenomena that occur in the expansion space, the heater, the regenerator, the cooler, the compression space, the surrounding walls, and the moving piston and displacer. In addition, the overall heat transfer, the indicated power, and the efficiency can be calculated. The CSUmod model is being converted to a two

  6. Stirling technology development at NASA GRC

    NASA Astrophysics Data System (ADS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.; Mason, Lee S.

    2002-01-01

    The Department of Energy, Stirling Technology Company (STC), and NASA Glenn Research Center (GRC) are developing a free-piston Stirling convertor for a high-efficiency Stirling Radioisotope Generator (SRG) for NASA Space Science missions. The SRG is being developed for multimission use, including providing electric power for unmanned Mars rovers and deep space missions. NASA GRC is conducting an in-house technology project to assist in developing the convertor for space qualification and mission implementation. Recent testing of 55-We Technology Demonstration Convertors (TDC's) built by STC includes mapping of a second pair of TDC's, single TDC testing, and TDC electromagnetic interference and electromagnetic compatibility characterization on a non-magnetic test stand. Launch environment tests of a single TDC without its pressure vessel to better understand the convertor internal structural dynamics and of dual-opposed TDC's with several engineering mounting structures with different natural frequencies have recently been completed. A preliminary life assessment has been completed for the TDC heater head, and creep testing of the IN718 material to be used for the flight convertors is underway. Long-term magnet aging tests are continuing to characterize any potential aging in the strength or demagnetization resistance of the magnets used in the linear alternator (LA). Evaluations are now beginning on key organic materials used in the LA and piston/rod surface coatings. GRC is also conducting finite element analyses for the LA, in part to look at the demagnetization margin on the permanent magnets. The world's first known integrated test of a dynamic power system with electric propulsion was achieved at GRC when a Hall-effect thruster was successfully operated with a free-piston Stirling power source. Cleveland State University is developing a multi-dimensional Stirling computational fluid dynamics code to significantly improve Stirling loss predictions and assist in

  7. Stirling Technology Development at NASA GRC. Revised

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.; Mason, Lee S.

    2002-01-01

    The Department of Energy, Stirling Technology Company (STC), and NASA Glenn Research Center (NASA Glenn) are developing a free-piston Stirling convertor for a high-efficiency Stirling Radioisotope Generator (SRG) for NASA Space Science missions. The SRG is being developed for multimission use, including providing electric power for unmanned Mars rovers and deep space missions. NASA Glenn is conducting an in-house technology project to assist in developing the convertor for space qualification and mission implementation. Recent testing, of 55-We Technology Demonstration Convertors (TDC's) built by STC includes mapping, of a second pair of TDC's, single TDC testing, and TDC electromagnetic interference and electromagnetic compatibility characterization on a nonmagnetic test stand. Launch environment tests of a single TDC without its pressure vessel to better understand the convertor internal structural dynamics and of dual-opposed TDC's with several engineering mounting structures with different natural frequencies have recently been completed. A preliminary life assessment has been completed for the TDC heater head, and creep testing of the IN718 material to be used for the flight convertors is underway. Long-term magnet aging tests are continuing to characterize any potential aging in the strength or demagnetization resistance of the magnets used in the linear alternator (LA). Evaluations are now beginning on key organic materials used in the LA and piston/rod surface coatings. NASA Glenn is also conducting finite element analyses for the LA, in part to look at the demagnetization margin on the permanent magnets. The world's first known integrated test of a dynamic power system with electric propulsion was achieved at NASA Glenn when a Hall-effect thruster was successfully operated with a free-piston Stirling power source. Cleveland State University is developing a multidimensional Stirling computational fluid dynamics code to significantly improve Stirling loss

  8. Stirling Technology Development at NASA GRC

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.; Mason, Lee S.

    2001-01-01

    The Department of Energy, Stirling Technology Company (STC), and NASA Glenn Research Center (NASA Glenn) are developing a free-piston Stirling convertor for a high efficiency Stirling Radioisotope Generator (SRG) for NASA Space Science missions. The SRG is being developed for multimission use, including providing electric power for unmanned Mars rovers and deep space missions. NASA Glenn is conducting an in-house technology project to assist in developing the convertor for space qualification and mission implementation. Recent testing of 55-We Technology Demonstration Convertors (TDCs) built by STC includes mapping of a second pair of TDCs, single TDC testing, and TDC electromagnetic interference and electromagnetic compatibility characterization on a nonmagnetic test stand. Launch environment tests of a single TDC without its pressure vessel to better understand the convertor internal structural dynamics and of dual-opposed TDCs with several engineering mounting structures with different natural frequencies have recently been completed. A preliminary life assessment has been completed for the TDC heater head, and creep testing of the IN718 material to be used for the flight convertors is underway. Long-term magnet aging tests are continuing to characterize any potential aging in the strength or demagnetization resistance of the magnets used in the linear alternator (LA). Evaluations are now beginning on key organic materials used in the LA and piston/rod surface coatings. NASA Glenn is also conducting finite element analyses for the LA, in part to look at the demagnetization margin on the permanent magnets. The world's first known integrated test of a dynamic power system with electric propulsion was achieved at NASA Glenn when a Hall-effect thruster was successfully operated with a free-piston Stirling power source. Cleveland State University is developing a multidimensional Stirling computational fluid dynamics code to significantly improve Stirling loss

  9. Reliability Assessment Approach for Stirling Convertors and Generators

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin R.; Schreiber, Jeffrey G.; Zampino, Edward; Best, Timothy

    2004-01-01

    Stirling power conversion is being considered for use in a Radioisotope Power System for deep-space science missions because it offers a multifold increase in the conversion efficiency of heat to electric power. Quantifying the reliability of a Radioisotope Power System that utilizes Stirling power conversion technology is important in developing and demonstrating the capability for long-term success. A description of the Stirling power convertor is provided, along with a discussion about some of the key components. Ongoing efforts to understand component life, design variables at the component and system levels, related sources, and the nature of uncertainties is discussed. The requirement for reliability also is discussed, and some of the critical areas of concern are identified. A section on the objectives of the performance model development and a computation of reliability is included to highlight the goals of this effort. Also, a viable physics-based reliability plan to model the design-level variable uncertainties at the component and system levels is outlined, and potential benefits are elucidated. The plan involves the interaction of different disciplines, maintaining the physical and probabilistic correlations at all the levels, and a verification process based on rational short-term tests. In addition, both top-down and bottom-up coherency were maintained to follow the physics-based design process and mission requirements. The outlined reliability assessment approach provides guidelines to improve the design and identifies governing variables to achieve high reliability in the Stirling Radioisotope Generator design.

  10. Stirling Power Convertors Demonstrated in Extended Operation

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    2005-01-01

    A 110-W Stirling Radioisotope Generator (SRG110) is being developed by Lockheed Martin Astronautics of Valley Forge, Pennsylvania, under contract to the Department of Energy of Germantown, Maryland. The generator will be a high-efficiency electric power source for NASA space exploration missions that can operate in the vacuum of deep space or in a gaseous atmosphere, such as on the surface of Mars. The generator converts heat supplied by the decay of a plutonium heat source into electric power for the spacecraft. In support of the SRG110 project, the NASA Glenn Research Center has established a technology effort that will provide some of the key data to ensure a successful transition to flight for what will be the first dynamic power system to be used in space. High system efficiency is obtained through the use of free-piston Stirling power-conversion technology. Glenn tasks include in-house testing of Stirling convertors and controllers, materials evaluation and heater head life assessment, structural dynamics, evaluation of electromagnetic interference, assessment of organics, and reliability analysis. There is also an advanced technology effort that is complementary to the near-term technology effort, intended to reduce the mass of the Stirling convertor and increase efficiency.

  11. New 5 Kilowatt Free-piston Stirling Space Convertor Developments

    NASA Technical Reports Server (NTRS)

    Brandhorst, Henry W., Jr.; Chapman, Peter A., Jr.

    2007-01-01

    The NASA Vision for Exploration of the moon may someday require a nuclear reactor coupled with a free-piston Stirling convertor at a power level of 30-40 kW. In the 1990s, Mechanical Technology Inc. s Stirling Engine Systems Division (some of whose Stirling personnel are now at Foster-Miller, Inc.) developed a 25 kW free piston Stirling Space Power Demonstrator Engine under the SP-100 program. This system consisted of two 12.5 kW engines connected at their hot ends and mounted in tandem to cancel vibration. Recently, NASA and DoE have been developing dual 55 W and 80 W Stirling convertor systems for potential use with radioisotope heat sources. Total test times of all convertors in this effort exceed 120,000 hours. Recently, NASA began a new project with Auburn University to develop a 5 kW, single convertor for potential use in a lunar surface reactor power system. Goals of this development program include a specific power in excess of 140 W/kg at the convertor level, lifetime in excess of five years and a control system that will safely manage the convertors in case of an emergency. Auburn University awarded a subcontract to Foster-Miller, Inc. to undertake development of the 5 kW Stirling Convertor Assembly. The characteristics of the design along with progress in developing the system will be described.

  12. Demagnetization Tests Performed on a Linear Alternator for a Stirling Power Convertor

    NASA Technical Reports Server (NTRS)

    Geng, Steven M.; Niedra, Janis M.; Schwarze, Gene E.

    2012-01-01

    The NASA Glenn Research Center (GRC) is conducting in-house research on rare-earth permanent magnets and linear alternators to assist in developing free-piston Stirling convertors for radioisotope space power systems and for developing advanced linear alternator technology. This research continues at GRC, but, with the exception of Advanced Stirling Radioisotope Generator references, the work presented in this paper was conducted in 2005. A special arc-magnet characterization fixture was designed and built to measure the M-H characteristics of the magnets used in Technology Demonstration Convertors developed under the 110-W Stirling Radioisotope Generator (SRG110) project. This fixture was used to measure these characteristics of the arc magnets and to predict alternator demagnetization temperatures in the SRG110 application. Demagnetization tests using the TDC alternator on the Alternator Test Rig were conducted for two different magnet grades: Sumitomo Neomax 44AH and 42AH. The purpose of these tests was to determine the demagnetization temperatures of the magnets for the alternator under nominal loads. Measurements made during the tests included the linear alternator terminal voltage, current, average power, magnet temperatures, and stator temperatures. The results of these tests were found to be in good agreement with predictions. Alternator demagnetization temperatures in the Advanced Stirling Convertor (ASC-developed under the Advanced Stirling Radioisotope Generator project) were predicted as well because the prediction method had been validated through the SRG110 alternator tests. These predictions led to a specification for maximum temperatures of the ASC pressure vessel.

  13. Recent Stirling Conversion Technology Developments and Operational Measurements at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Schifer, Nicholas A.

    2010-01-01

    In support of the Advanced Stirling Radioisotope Generator (ASRG) project and other potential applications, NASA Glenn Research Center (GRC) has initiated convertor technology development efforts in the areas of acoustic emission, electromagnetic field mitigation, thermoacoustic Stirling conversion, and multiple-cylinder alpha arrangements of Stirling machines. The acoustic emission measurement effort was developed as a health monitoring metric for several Stirling convertors undergoing life testing. While accelerometers have been used in the past to monitor dynamic signature, the acoustic sensors were chosen to monitor cycle events, such gas bearing operation. Several electromagnetic interference (EMI) experiments were performed on a pair of Advanced Stirling Convertors (ASC). These tests demonstrated that a simple bucking coil was capable of reducing the alternating current (ac) magnetic field below the ASRG system specification. The thermoacoustic Stirling concept eliminates the displacer typically found in Stirling machines by making use of the pressure oscillations of a traveling acoustic wave. A 100 W-class thermoacoustic Stirling prototype manufactured by Northrop Grumman Space and Technology was received and tested. Another thermoacoustic prototype designed and fabricated by Sunpower, Inc., will be tested in the near future. A four cylinder free piston alpha prototype convertor was received from Sunpower, Inc. and has been tested at GRC. This hardware was used as a proof of concept to validate thermodynamic models and demonstrate stable operation of multiple-cylinder free-piston Stirling conversion. This paper will discuss each of these activities and the results they produced.

  14. Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

    NASA Technical Reports Server (NTRS)

    Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

    2013-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 C temperature increase from the nominal vapor temperature. The 19 C temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental

  15. Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

    NASA Technical Reports Server (NTRS)

    Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

    2013-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 degC temperature increase from the nominal vapor temperature. The 19 degC temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental

  16. Developmental Considerations on the Free-Piston Stirling Power Convertor for Use in Space

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    2006-01-01

    Free-piston Stirling power conversion has been considered a candidate for radioisotope power systems for space for more than a decade. Prior to the free-piston Stirling architecture, systems were designed with kinematic Stirling engines with rotary alternators to convert heat to electricity. These systems were proposed with lightly loaded linkages to achieve the necessary life. When the free-piston configuration was initially proposed, it was thought to be attractive due to the relatively high conversion efficiency, acceptable mass, and the potential for long life and high reliability. These features have consistently been recognized by teams that have studied technology options for radioisotope power systems. Since free-piston Stirling power conversion was first considered for space power applications, there have been major advances in three general areas of development: demonstration of life and reliability, the success achieved by Stirling cryocoolers in flight, and the overall developmental maturity of the technology for both flight and terrestrial applications. Based on these advances, free-piston Stirling convertors are currently being developed for a number of terrestrial applications. They commonly operate with the power, efficiency, life, and reliability as intended, and much of the development now centers on system integration. This paper will summarize the accomplishments of free-piston Stirling power conversion technology over the past decade, review the status, and discuss the challenges that remain.

  17. Developmental Considerations on the Free-piston Stirling Power Convertor for Use in Space

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    2007-01-01

    Free-piston Stirling power conversion has been considered a candidate for radioisotope power systems for space for more than a decade. Prior to the free-piston Stirling architecture, systems were designed with kinematic Stirling engines with rotary alternators to convert heat to electricity. These systems were proposed with lightly loaded linkages to achieve the necessary life. When the free-piston configuration was initially proposed, it was thought to be attractive due to the relatively high conversion efficiency, acceptable mass, and the potential for long life and high reliability. These features have consistently been recognized by teams that have studied technology options for radioisotope power systems. Since free-piston Stirling power conversion was first considered for space power applications, there have been major advances in three general areas of development: demonstration of life and reliability, the success achieved by Stirling cryocoolers in flight, and the overall developmental maturity of the technology for both flight and terrestrial applications. Based on these advances, free-piston Stirling convertors are currently being developed for a number of terrestrial applications. They commonly operate with the power, efficiency, life, and reliability as intended, and much of the development now centers on system integration. This paper will summarize the accomplishments of free-piston Stirling power conversion technology over the past decade, review the status, and discuss the challenges that remain.

  18. Stirling engine application study

    SciTech Connect

    Teagan, W.P.; Cunningham, D.R.

    1983-03-01

    The potential for Stirling engine applications in the 0.5 to 5000 hp output range is assessed. The following are included: a market survey of potential engine applications, classification of applications, conventional engine markets and performance characteristics, status of Sterling engine systems, selection of application classes for Stirling engines, and the possible effects of technology, economic conditions, and regulatory changes. (MHR)

  19. Stirling Engine Heat Pump

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru

    Recent advances in the feasibility studies related to the Stirling engines and Stirling engine heat pumps which have been considered attractive due to their promising role in helping to solve the global environmental and energy problems,are reviewed. This article begins to describe the brief history of the Stirling engines and theoretical thermodynamic analysis of the Stirling cycle in order to understand several advantages on the Stirling engine. Furthermore,they could throw light on our question why the dream engines had not been promoted to practical applications during two hundred years. The present review shows that the Stirling engines with several unique advantages including 30 to 40% thermal efficiency and preferable exhaust characteristics,had been designed and constructed by recent tackling for the development of the advanced automobile and other applications using them. Based on the current state of art,it is being provided to push the Stirling engines combined with heat pumps based on the reversed Rankine cycle to the market. At present,however, many problems, especially for the durability, cost, and delicate engine parts must be enforced to solve. In addition,there are some possibilities which can increase the attractiveness of the Stirling engines and heat pumps. The review closes with suggestions for further research.

  20. Stirling Engine Gets Revisited

    ERIC Educational Resources Information Center

    Thompson, Frank

    2010-01-01

    One of the basic truths regarding energy conversion is that no thermodynamic cycle can be devised that is more efficient than a Carnot cycle operating between the same temperature limits. The efficiency of the Stirling cycle (patented by Rev. Robert Stirling in 1816) can approach that of the Carnot cycle and yet has not had the commercial success…

  1. Stirling engines for automobiles

    NASA Technical Reports Server (NTRS)

    Beremand, D. G.

    1979-01-01

    The results of recent and ongoing automobile Stirling engine development efforts are reviewed and technology status and requirements are identified. Key technology needs include those for low cost, high temperature (1300 - 1500 F) metal alloys for heater heads, and reliable long-life, low-leakage shaft seals. Various fuel economy projections for Stirling powered automobiles are reviewed and assessed.

  2. The Stirling Project

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Stirling Engine's advanced technology engine offers multiple advantages, principal among them reduced fuel consumption and lower exhaust emissions than comparable internal combustion auto engines, plus multifuel capability. Stirling can use gasoline, kerosene, diesel fuel, jet fuel, alcohol, methanol, butane and that's not the whole list. Applications include irrigation pumping, heat pumps, and electricity generation for submarine, Earth and space systems.

  3. Free piston stirling engines

    SciTech Connect

    Walker, C.

    1985-01-01

    This book presents a basic introduction to free piston Stirling engine technology through a review of specialized background material. It also includes information based on actual construction and operation experience with these machines, as well as theoretical and analytical insights into free piston Stirling engine technology.

  4. Advanced Controller for the Free-Piston Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Gerber, Scott S.; Jamison, Mike; Roth, Mary Ellen; Regan, Timothy F.

    2004-01-01

    The free-piston Stirling power convertor is being considered as an advanced power conversion technology to be used for future NASA deep space missions requiring long life radioisotope power systems. This technology has a conversion efficiency of over 25%, which is significantly higher than the efficiency of the Radioisotope Thermal-electric Generators (RTG) now in use. The NASA Glenn Research Center has long been recognized as a leader in Stirling technology and is responsible for the development of advanced technologies that are intended to significantly improve key characteristics of the Stirling convertor. The advanced technologies identified for development also consider the requirements of potential future missions and the new capabilities that have become available in the associated technical areas. One of the key areas identified for technology development is the engine controller. To support this activity, an advanced controller is being developed for the Stirling power convertor. This controller utilizes active power factor correction electronics and microcontroller-based controls. The object of this paper is to present an overview of the advanced controller concept with modeling, simulation and hardware test data.

  5. Investigation of Insulation Materials for Future Radioisotope Power Systems

    NASA Technical Reports Server (NTRS)

    Cornell, Peggy A.; Hurwitz, Frances I.; Ellis, David L.; Schmitz, Paul C.

    2013-01-01

    NASA's Radioisotope Power Systems (RPS) Technology Advancement Project is developing next generation high-temperature insulation materials that directly benefit thermal management and improve performance of RPS for future science missions. Preliminary studies on the use of multilayer insulation (MLI) for Stirling convertors used on the Advanced Stirling Radioisotope Generator (ASRG) have shown the potential benefits of MLI for space vacuum applications in reducing generator size and increasing specific power (W/kg) as compared to the baseline Microtherm HT (Microtherm, Inc.) insulation. Further studies are currently being conducted at NASA Glenn Research Center on candidate MLI foils and aerogel composite spacers. This paper presents the method of testing of foils and spacers and experimental results to date.

  6. Investigation of Insulation Materials for Future Radioisotope Power Systems (RPS)

    NASA Technical Reports Server (NTRS)

    Cornell, Peggy A.; Hurwitz, Frances I.; Ellis, David L.; Schmitz, Paul C.

    2013-01-01

    NASA's Radioisotope Power System (RPS) Technology Advancement Project is developing next generation high temperature insulation materials that directly benefit thermal management and improve performance of RPS for future science missions. Preliminary studies on the use of multilayer insulation (MLI) for Stirling convertors used on the Advanced Stirling Radioisotope Generator (ASRG) have shown the potential benefits of MLI for space vacuum applications in reducing generator size and increasing specific power (W/kg) as compared to the baseline Microtherm HT (Microtherm, Inc.) insulation. Further studies are currently being conducted at NASA Glenn Research Center (GRC) on candidate MLI foils and aerogel composite spacers. This paper presents the method of testing of foils and spacers and experimental results to date.

  7. Isotope powered stirling generator for terrestrial applications

    NASA Astrophysics Data System (ADS)

    Tingey, Garth L.; Sorensen, Gerald C.; Ross, Brad A.

    1995-01-01

    An electric power supply, small enough to be man-portable, is being developed for remote, terrestrial applications. This system is designed for an operating lifetime of five years without maintenance or refueling. A small Radioisotope Stirling Generator (RSG) has been developed. The energy source of the generator is a 60 watt plutonium-238 fuel clad used in the General Purpose Heat Sources (GPHS) developed for space applications. A free piston Stirling ENgine drives a linear alternator to convert the heat to power. The system weighs about 7.5 kg and produces 11 watts AC power with a conversion efficiency of 18.5%. Two engine models have been designed, fabricated, and tested to data: (a) a development model instrumented to confirm and test parameters, and (b) an electrically heated model with an electrical heater equipped power input leads. Critical components have been tested for 10,000 to 20,000 hours. One complete generator has been operating for over 11,000 hours. Radioisotope heated prototypes are expected to be fabricated and tested in late 1995.

  8. Isotope powered stirling generator for terrestrial applications

    SciTech Connect

    Tingey, G.L.; Sorensen, G.C.; Ross, B.A.

    1995-01-20

    An electric power supply, small enough to be man-portable, is being developed for remote, terrestrial applications. This system is designed for an operating lifetime of five years without maintenance or refueling. A small Radioisotope Stirling Generator (RSG) has been developed. The energy source of the generator is a 60 watt plutonium-238 fuel clad used in the General Purpose Heat Sources (GPHS) developed for space applications. A free piston Stirling ENgine drives a linear alternator to convert the heat to power. The system weighs about 7.5 kg and produces 11 watts AC power with a conversion efficiency of 18.5%. Two engine models have been designed, fabricated, and tested to data: (a) a development model instrumented to confirm and test parameters, and (b) an electrically heated model with an electrical heater equipped power input leads. Critical components have been tested for 10,000 to 20,000 hours. One complete generator has been operating for over 11,000 hours. Radioisotope heated prototypes are expected to be fabricated and tested in late 1995. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}

  9. Isotope powered Stirling generator for terrestrial applications

    SciTech Connect

    Tingey, G.L.; Sorensen, G.C.; Ross, B.A.

    1995-01-01

    An electric power supply, small enough to be man-portable, is being developed for remote, terrestrial applications. This system is designed for an operating lifetime of five years without maintenance or refueling. A small Radioisotope Stirling Generator (RSG) has been developed. The energy source of the generator is a 60 watt plutonium-238 fuel clad used in the General Purpose Heat Sources (GPHS) developed for space applications. A free piston Stirling Engine drives a linear alternator to convert the heat to power. The system weighs about 7.5 kg and produces 11 watts AC power with a conversion efficiency of 18.5%. Two engine models have been designed, fabricated, and tested to date: (a) a developmental model instrumented to confirm and test parameters, and (b) an electrically heated model with an electrical heater equipped power input leads. Critical components have been tested for 10,000 to 20,000 hours. One complete generator has been operating for over 11,000 hours. Radioisotope heated prototypes are expected to be fabricated and tested in late 1995.

  10. NASA Radioisotope Power Conversion Technology NRA Overview

    NASA Technical Reports Server (NTRS)

    Anderson, David J.

    2005-01-01

    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.

  11. NASA Radioisotope Power Conversion Technology NRA Overview

    NASA Technical Reports Server (NTRS)

    Anderson, David J.

    2005-01-01

    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.

  12. Design and Fabrication of a Stirling Thermal Vacuum Test

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Schreiber, Jeffrey G.

    2004-01-01

    A Stirling Radioisotope Generator (SRG110) is being developed for potential use on future NASA space science missions. The development effort is being conducted by Lockheed Martin under contract to the Department of Energy (DOE). The Stirling Technology Company supplies the free-piston Stirling power convertors, and NASA Glenn Research Center (GRC) provides support to the effort in a range of technologies. This generator features higher efficiency and specific power compared to the currently used alternatives. One potential application for the generator would entail significant cruise time in the vacuum of deep space. A test has been conceived at GRC to demonstrate functionality of the Stirling convertors in a thermal vacuum environment. The test article resembles the configuration of the SRG, however the requirement for low mass was not considered. This test will demonstrate the operation of the Stirling convertors in the thermal vacuum environment, simulating deep space, over an extended period of operation. The analysis, design, and fabrication of the test article will be described in this paper.

  13. Work Began on Contracts for Radioisotope Power Conversion Technology Research and Development

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.

    2005-01-01

    NASA has had a history of successful space flight missions that depended on radioisotope-fueled power systems. These Radioisotope Power Systems (RPSs) converted the heat generated from the decay of radioisotope material into useful electrical power. An RPS is most attractive in applications where photovoltaics are not optimal, such as deep-space applications where the solar flux is too low or extended applications on planets such as Mars where the day/night cycle, settling of dust, and life requirements limit the usefulness of photovoltaics. NASA s Radioisotope Power Conversion Technology (RPCT) Program is developing next-generation power-conversion technologies that will enable future missions that have requirements that cannot be met by the two RPS flight systems currently being developed by the Department of Energy for NASA: the Multi-Mission Radioisotope Thermoelectric Generator and the Stirling Radioisotope Generator (SRG).

  14. Advanced Radioisotope Power Conversion Technology Research and Development

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.

    2004-01-01

    NASA's Radioisotope Power Conversion Technology program is developing next generation power conversion technologies that will enable future missions that have requirements that cannot be met by either the ubiquitous photovoltaic systems or by current Radioisotope Power System (RPS) technology. Performance goals of advanced radioisotope power systems include improvement 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. NASA has awarded ten contracts in the technology areas of Brayton, Stirling, Thermoelectric, and Thermophotovoltaic power conversion including five development contracts that deal with more mature technologies and five research contracts. The Advanced RPS Systems Assessment Team includes members from NASA GRC, JPL, DOE and Orbital Sciences whose function is to review the technologies being developed under the ten Radioisotope Power Conversion Technology contracts and assess their relevance to NASA's future missions. Presented is an overview of the ten radioisotope power conversion technology contracts and NASA's Advanced RPS Systems Assessment Team.

  15. Stirling Convertor Extended Operation Testing and Data Analysis at Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Cornell, Peggy A.; Lewandowski, Edward J.; Oriti, Salvatore M.; Wilson, Scott D.

    2010-01-01

    Extended operation of Stirling convertors is essential to the development of radioisotope power systems and their potential use for longduration missions. To document the reliability of the convertors, regular monitoring and analysis of the extended operation data is particularly valuable, allowing us to better understand and quantify long-life characteristics of the convertors. Furthermore, investigation and comparison of the extended operation data to baseline performance data provides an opportunity to understand system behavior should any off-nominal performance occur. Glenn Research Center (GRC) has tested 16 Stirling convertors under 24-hr unattended extended operation, including four that have operated in a thermal vacuum environment and two that are operating in the Advanced Stirling Radioisotope Generator Engineering Unit. Ten of the sixteen convertors are the Advanced Stirling Convertors (ASC) developed by Sunpower, Inc. with GRC. These are highly efficient (conversion efficiency of up to 38 percent for the ASC-1), low-mass convertors that have evolved through technologically progressive convertor builds. Six convertors at GRC are Technology Demonstration Convertors from Infinia Corporation. They have achieved greater than 27 percent conversion efficiency and have accumulated over 185,000 of the total 265,000 hr of extended operation at GRC. This paper presents the extended operation testing and data analysis of free-piston Stirling convertors at NASA GRC as well as how these tests have contributed to the Stirling convertor s progression toward flight.

  16. Thermodynamics: A Stirling effort

    NASA Astrophysics Data System (ADS)

    Horowitz, Jordan M.; Parrondo, Juan M. R.

    2012-02-01

    The realization of a single-particle Stirling engine pushes thermodynamics into stochastic territory where fluctuations dominate, and points towards a better understanding of energy transduction at the microscale.

  17. Liquid piston Stirling engines

    SciTech Connect

    West, C.D.

    1983-01-01

    This book is a presentation on piston stirling engines. Topics covered include: liquid piston engines; basic design and power calculations; more advanced power calculations; design example; and past research work and some present research needs.

  18. Stirling machine operating experience

    NASA Technical Reports Server (NTRS)

    Ross, Brad; Dudenhoefer, James E.

    1991-01-01

    Numerous Stirling machines have been built and operated, but the operating experience of these machines is not well known. It is important to examine this operating experience in detail, because it largely substantiates the claim that Stirling machines are capable of reliable and lengthy lives. The amount of data that exists is impressive, considering that many of the machines that have been built are developmental machines intended to show proof of concept, and were not expected to operate for any lengthy period of time. Some Stirling machines (typically free-piston machines) achieve long life through non-contact bearings, while other Stirling machines (typically kinematic) have achieved long operating lives through regular seal and bearing replacements. In addition to engine and system testing, life testing of critical components is also considered.

  19. The optimization of Stirling refrigerator and Stirling heat engine

    NASA Astrophysics Data System (ADS)

    Zhu, Xin-Mei

    2007-03-01

    The optimization of an irreversible Stirling refrigerator or a Stirling heat engine is an important research subject for a long time. Taking into account of the influence of mixed thermal resistance and regeneration loss in the performance study, we have derived the optimal relation of both of them. For Stirling refrigerator, we have deduced the optimal relation between the thermal resistance coefficient and the efficiency. To the Stirling heat engine, we have deduced the optimal relation between the power output and the efficiency. The conclusions obtained mirror the observed performance of the Stirling refrigerator or the Stirling heat engine quite well. Thus, the results may provide a new theoretical guidance to the optimal design and the selection of optimal operating condition of the Stirling refrigerator or the Stirling heat engine.

  20. Advanced Stirling Convertor Testing at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.; Poriti, Sal

    2010-01-01

    The NASA Glenn Research Center (GRC) has been testing high-efficiency free-piston Stirling convertors for potential use in radioisotope power systems (RPSs) since 1999. The current effort is in support of the Advanced Stirling Radioisotope Generator (ASRG), which is being developed by the U.S. Department of Energy (DOE), Lockheed Martin Space Systems Company (LMSSC), Sunpower, Inc., and the NASA GRC. This generator would use two high-efficiency Advanced Stirling Convertors (ASCs) to convert thermal energy from a radioisotope heat source into electricity. As reliability is paramount to a RPS capable of providing spacecraft power for potential multi-year missions, GRC provides direct technology support to the ASRG flight project in the areas of reliability, convertor and generator testing, high-temperature materials, structures, modeling and analysis, organics, structural dynamics, electromagnetic interference (EMI), and permanent magnets to reduce risk and enhance reliability of the convertor as this technology transitions toward flight status. Convertor and generator testing is carried out in short- and long-duration tests designed to characterize convertor performance when subjected to environments intended to simulate launch and space conditions. Long duration testing is intended to baseline performance and observe any performance degradation over the life of the test. Testing involves developing support hardware that enables 24/7 unattended operation and data collection. GRC currently has 14 Stirling convertors under unattended extended operation testing, including two operating in the ASRG Engineering Unit (ASRG-EU). Test data and high-temperature support hardware are discussed for ongoing and future ASC tests with emphasis on the ASC-E and ASC-E2.

  1. Stirling engine application study

    NASA Technical Reports Server (NTRS)

    Teagan, W. P.; Cunningham, D.

    1983-01-01

    A range of potential applications for Stirling engines in the power range from 0.5 to 5000 hp is surveyed. Over one hundred such engine applications are grouped into a small number of classes (10), with the application in each class having a high degree of commonality in technical performance and cost requirements. A review of conventional engines (usually spark ignition or Diesel) was then undertaken to determine the degree to which commercial engine practice now serves the needs of the application classes and to detemine the nature of the competition faced by a new engine system. In each application class the Stirling engine was compared to the conventional engines, assuming that objectives of ongoing Stirling engine development programs are met. This ranking process indicated that Stirling engines showed potential for use in all application classes except very light duty applications (lawn mowers, etc.). However, this potential is contingent on demonstrating much greater operating life and reliability than has been demonstrated to date by developmental Stirling engine systems. This implies that future program initiatives in developing Stirling engine systems should give more emphasis to life and reliability issues than has been the case in ongoing programs.

  2. Multi-d CFD Modeling of a Free-piston Stirling Convertor at NASA Glenn

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.; Dyson, Rodger W.; Tew, Roy C.; Ibrahim, Mounir B.

    2004-01-01

    A high efficiency Stirling Radioisotope Generator (SRG) is being developed for possible use in long duration space science missions. NASA s advanced technology goals for next generation Stirling convertors include increasing the Carnot efficiency and percent of Carnot efficiency. To help achieve these goals, a multidimensional Computational Fluid Dynamics (CFD) code is being developed to numerically model unsteady fluid flow and heat transfer phenomena of the oscillating working gas inside Stirling convertors. Simulations of the Stirling convertors for the SRG will help characterize the thermodynamic losses resulting from fluid flow and heat transfer between the working gas and solid walls. The current CFD simulation represents approximated 2-dimensional convertor geometry. The simulation solves the Navier Stokes equations for an ideal helium gas oscillating at low speeds. The current simulation results are discussed.

  3. A 3-D Magnetic Analysis of a Linear Alternator For a Stirling Power System

    NASA Technical Reports Server (NTRS)

    Geng, Steven M.; Schwarze, Gene E.; Niedra, Janis M.

    2000-01-01

    The NASA Glenn Research Center and the Department of Energy (DOE) are developing advanced radioisotope Stirling convertors, under contract with Stirling Technology Company (STC), for space applications. Of critical importance to the successful development of the Stirling convertor for space power applications is the development of a lightweight and highly efficient linear alternator. This paper presents a 3-D finite element method (FEM) approach for evaluating Stirling convertor linear alternators. Preliminary correlations with open-circuit voltage measurements provide an encouraging level of confidence in the model. Spatial plots of magnetic field strength (H) are presented in the region of the exciting permanent magnets. These plots identify regions of high H, where at elevated temperature and under electrical load, the potential to alter the magnetic moment of the magnets exists. This implies the need for further testing and analysis.

  4. Realistic Specific Power Expectations for Advanced Radioisotope Power Systems

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    2006-01-01

    Radioisotope Power Systems (RPS) are being considered for a wide range of future NASA space science and exploration missions. Generally, RPS offer the advantages of high reliability, long life, and predictable power production regardless of operating environment. Previous RPS, in the form of Radioisotope Thermoelectric Generators (RTG), have been used successfully on many NASA missions including Apollo, Viking, Voyager, and Galileo. NASA is currently evaluating design options for the next generation of RPS. Of particular interest is the use of advanced, higher efficiency power conversion to replace the previous thermoelectric devices. Higher efficiency reduces the quantity of radioisotope fuel and potentially improves the RPS specific power (watts per kilogram). Power conversion options include Segmented Thermoelectric (STE), Stirling, Brayton, and Thermophotovoltaic (TPV). This paper offers an analysis of the advanced 100 watt-class RPS options and provides credible projections for specific power. Based on the analysis presented, RPS specific power values greater than 10 W/kg appear unlikely.

  5. Assessment of the Free-piston Stirling Convertor as a Long Life Power Convertor for Space

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    2001-01-01

    There is currently a renewed interest in the use of free-piston Stirling power convertors for space power applications. More specifically, the Stirling convertor is being developed to be part of the Stirling Radioisotope Power System to supply electric power to spacecraft for NASA deep space science missions. The current development effort involves the Department of Energy, Germantown, MD, the NASA Glenn Research Center, Cleveland, OH, and the Stirling Technology Company, Kennewick, WA. The Stirling convertor will absorb heat supplied from the decay of plutonium dioxide contained in the General Purpose Heat Source modules and convert it into electricity to power the spacecraft. For many years the "potentials" of the free-piston Stirling convertor have been publicized by it's developers. Among these "potentials" were long life and high reliability. This paper will present an overview of the critical areas that enable long life of the free-piston Stirling power convertor, and present some of the techniques that have been used when long life has been achieved.

  6. Optimized Heat Pipe Backup Cooling System Tested with a Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Schwendeman, Carl L.; Tarau, Calin; Schifer, Nicholas A.; Anderson, William G.; Garner, Scott

    2016-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal variable conductance heat pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor by bypassing the heat during stops. In a previous NASA Small Business Innovation Research (SBIR) Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for the Stirling RPS. In 2012, one of these VCHPs was successfully tested at NASA Glenn Research Center with a Stirling convertor as an Advanced Stirling Radioisotope Generator (ASRG) backup cooling system. The prototype; however, was not optimized and did not reflect the final heat rejection path. ACT through further funding has developed a semioptimized prototype with the finalized heat path for testing at Glenn with a Stirling convertor. The semioptimized system features a two-phase radiator and is significantly smaller and lighter than the prior prototype to reflect a higher level of flight readiness. The VCHP is designed to activate and remove heat from the GPHS during stoppage with a small temperature increase from the nominal vapor temperature. This small temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the multilayer insulation (MLI). The VCHP passively allows the Stirling convertor to be turned off multiple times during a mission with potentially unlimited off durations. Having the ability to turn the Stirling off allows for the Stirling to be reset and reduces vibrations on the platform during sensitive measurements or

  7. Structural Dynamics Testing of Advanced Stirling Convertor Components

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Williams, Zachary Douglas

    2013-01-01

    NASA Glenn Research Center has been supporting the development of Stirling energy conversion for use in space. Lockheed Martin has been contracted by the Department of Energy to design and fabricate flight-unit Advanced Stirling Radioisotope Generators, which utilize Sunpower, Inc., free-piston Advanced Stirling Convertors. The engineering unit generator has demonstrated conversion efficiency in excess of 20 percent, offering a significant improvement over existing radioisotope-fueled power systems. NASA Glenn has been supporting the development of this generator by developing the convertors through a technology development contract with Sunpower, and conducting research and experiments in a multitude of areas, such as high-temperature material properties, organics testing, and convertor-level extended operation. Since the generator must undergo launch, several launch simulation tests have also been performed at the convertor level. The standard test sequence for launch vibration exposure has consisted of workmanship and flight acceptance levels. Together, these exposures simulate what a flight convertor will experience. Recently, two supplementary tests were added to the launch vibration simulation activity. First was a vibration durability test of the convertor, intended to quantify the effect of vibration levels up to qualification level in both the lateral and axial directions. Second was qualification-level vibration of several heater heads with small oxide inclusions in the material. The goal of this test was to ascertain the effect of the inclusions on launch survivability to determine if the heater heads were suitable for flight.

  8. Advanced Stirling Convertor Testing at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore

    2007-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Space Systems (LMSS), Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for use as a power system on space science and exploration missions. This generator will make use of the free-piston Stirling convertors to achieve higher conversion efficiency than currently available alternatives. The ASRG will utilize two Advanced Stirling Convertors (ASC) to convert thermal energy from a radioisotope heat source to electricity. NASA GRC has initiated several experiments to demonstrate the functionality of the ASC, including: in-air extended operation, thermal vacuum extended operation, and ASRG simulation for mobile applications. The in-air and thermal vacuum test articles are intended to provide convertor performance data over an extended operating time. These test articles mimic some features of the ASRG without the requirement of low system mass. Operation in thermal vacuum adds the element of simulating deep space. This test article is being used to gather convertor performance and thermal data in a relevant environment. The ASRG simulator was designed to incorporate a minimum amount of support equipment, allowing integration onto devices powered directly by the convertors, such as a rover. This paper discusses the design, fabrication, and implementation of these experiments.

  9. Stirling technology development status

    NASA Astrophysics Data System (ADS)

    Dochat, George R.; Dudenhoefer, James E.

    1993-01-01

    Free-piston Stirling power converters have the potential to meet the many future space power requirements for a wide variety of applications with less mass, better efficiency, and less total area (collector and radiator) than other power converter options. These benefits result in significant dollar savings over the projected mission lifetime. The National Aeronautics and Space Administration (NASA)—Lewis Research Center (LeRC), which has the responsibility to evaluate and develop power technologies that can satisfy anticipated future space mission power requirements, has been developing free-piston Stirling power converters and is bringing the Stirling technology to readiness. As the principal contractor to NASA-LeRC, Mechanical Technology Incorporated (MTI) is under contract to develop the necessary space Stirling technology but also demonstrate the readiness of the technology in two generations of full-scale power converters. The first generation Stirling power converter, the component test power converter (CTPC), initiated cold end testing at the end of 1991, with hot testing scheduled during 1992. This paper reviews test progress of the CTPC including the initial hot engine test results. Modifications incorporated into the CTPC from the earlier space power demonstrator engine are reviewed as well.

  10. Stirling technology development status

    SciTech Connect

    Dochat, G.R. ); Dudenhoefer, J.E. )

    1993-01-15

    Free-piston Stirling power converters have the potential to meet the many future space power requirements for a wide variety of applications with less mass, better efficiency, and less total area (collector and radiator) than other power converter options. These benefits result in significant dollar savings over the projected mission lifetime. The National Aeronautics and Space Administration (NASA)---Lewis Research Center (LeRC), which has the responsibility to evaluate and develop power technologies that can satisfy anticipated future space mission power requirements, has been developing free-piston Stirling power converters and is bringing the Stirling technology to readiness. As the principal contractor to NASA-LeRC, Mechanical Technology Incorporated (MTI) is under contract to develop the necessary space Stirling technology but also demonstrate the readiness of the technology in two generations of full-scale power converters. The first generation Stirling power converter, the component test power converter (CTPC), initiated cold end testing at the end of 1991, with hot testing scheduled during 1992. This paper reviews test progress of the CTPC including the initial hot engine test results. Modifications incorporated into the CTPC from the earlier space power demonstrator engine are reviewed as well.

  11. Solar Stirling for Deep Space Applications

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    1999-01-01

    A study was performed to quantify the performance of solar thermal power systems for deep space planetary missions. The study incorporated projected advances in solar concentrator and energy conversion technologies. These technologies included inflatable structures, lightweight primary concentrators, high efficiency secondary concentrators, and high efficiency Stirling convertors. Analyses were performed to determine the mass and deployed area of multi-hundred watt solar thermal power systems for missions out to 40 astronomical units. Emphasis was given to system optimization, parametric sensitivity analyses, and concentrator configuration comparisons. The results indicated that solar thermal power systems are a competitive alternative to radioisotope systems out to 10 astronomical units without the cost or safety implications associated with nuclear sources.

  12. Extended Operation of Stirling Convertors at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore, M.

    2012-01-01

    NASA Glenn Research Center (GRC) has been supporting development of free-piston Stirling conversion technology for spaceflight electrical power generation since 1999. GRC has also been supporting the development of the Advanced Stirling Radioisotope Generator (ASRG) since 2006. A key element of the ASRG project is providing life, reliability, and performance data for the Advanced Stirling Convertor (ASC). The Thermal Energy Conversion branch at GRC is conducting extended operation of several free-piston Stirling convertors. The goal of this effort is to generate long-term performance data (tens of thousands of hours) on multiple units to build a life and reliability database. Currently, GRC is operating 18 convertors. This hardware set includes Technology Demonstration Convertors (TDCs) from Infinia Corporation, of which one pair (TDCs #13 and #14) has accumulated over 60,000 hr (6.8 years) of operation. Also under test are various Sunpower, Inc. convertors that were fabricated during the ASC development activity, including ASC-0, ASC-E (including those in the ASRG engineering unit), and ASC-E2. The ASC-E2s also completed, or are in progress of completing workmanship vibration testing, performance mapping, and extended operation. Two ASC-E2 units will also be used for durability testing, during which components will be stressed to levels above nominal mission usage. Extended operation data analyses from these tests are covered in this paper.

  13. Recent Stirling Conversion Technology Developments and Operational Measurements

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore; Schifer, Nicholas

    2009-01-01

    Under contract to the Department of Energy (DOE), Lockheed Martin Space Systems Company (LMSSC) has been developing the Advanced Stirling Radioisotope Generator (ASRG). The use of Stirling technology introduces a four-fold increase in conversion efficiency over Radioisotope Thermoelectric Generators (RTGs), and thus the ASRG in an attractive power system option for future science missions. In August of 2008, the ASRG engineering unit (EU) was delivered to NASA Glenn Research Center (GRC). The engineering unit design resembles that of a flight unit, with the exception of electrical heating in place of a radioisotope source. Prior to delivery, GRC personnel prepared a test station continuous, unattended operation of the engineering unit. This test station is capable of autonomously monitoring the unit's safe operation and recording. , .. , .... performance data. Generator parameters recorded include temperatures, electrical power output, and thelmal power input. Convertor specific parameters are also recorded such as alternator voltage, current, piston amplitude, and frequency. Since November 2008, the ASRG EU has accumulated over 4,000 hours of operation. Initial operation was conducted using the AC bus control method in lieu of the LMSSC active power factor connecting controller. Operation on the LMSSC controller began in February 2009. This paper discusses the entirety of ASRG EU operation thus far, as well as baseline performance data at GRC and LMSSC, and comparison of performance using each control method.

  14. Stirling Module Development Overview

    NASA Technical Reports Server (NTRS)

    Livingston, F. R.

    1984-01-01

    The solar parabolic dish Stirling engine electrically generating module consists of a solar collector coupled to a Stirling engine powered electrical generator. The module is designed to convert solar power to electrical power in parallel with numerous identical units coupled to an electrical utility power grid. The power conversion assembly generates up to 25 kilowatts at 480 volts potential/3 phase/alternating current. Piston rings and seals with gas leakage have not occurred, however, operator failures resulted in two burnt out receivers, while material fatigue resulted in a broken piston rod between the piston rod seal and cap seal.

  15. The Phillips Stirling engine

    SciTech Connect

    Hargreaves, C.M.

    1991-01-01

    This book is about the Stirling engine and its development from the heavy cast-iron machine of the 19th century to that of today. It is a history of a research effort spanning nearly 50 years, together with an outline of principles, and some technical details and descriptions of the more important engines. Contents include: the hot-air engine; the 20th-century revival; the Stirling cycle; rhombic-drive engines; heating and cooling; pistons and seals; electric generators and heat pumps; exotic heat sources; the engine and the environment; swashplate engines; and the past and the future.

  16. Radioisotope Power Systems Program: A Program Overview

    NASA Technical Reports Server (NTRS)

    Hamley, John A.

    2016-01-01

    NASA's Radioisotope Power Systems (RPS) Program continues to plan, mature research in energy conversion, and partners with the Department of Energy (DOE) 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 potential future mission needs. Recent programs responsibilities include providing investment recommendations to NASA stakeholders on emerging thermoelectric and Stirling energy conversion technologies and insight on NASA investments at DOE in readying a generator for the Mars 2020 mission. This presentation provides an overview of the RPS Program content and status and the approach used to maintain the readiness of RPS to support potential future NASA missions.

  17. Structural Analyses of Stirling Power Convertor Heater Head for Long-Term Reliability, Durability, and Performance

    NASA Technical Reports Server (NTRS)

    Halford, Gary R.; Shah, Ashwin; Arya, Vinod K.; Krause, David L.; Bartolotta, Paul A.

    2002-01-01

    Deep-space missions require onboard electric power systems with reliable design lifetimes of up to 10 yr and beyond. A high-efficiency Stirling radioisotope power system is a likely candidate for future deep-space missions and Mars rover applications. To ensure ample durability, the structurally critical heater head of the Stirling power convertor has undergone extensive computational analyses of operating temperatures (up to 650 C), stresses, and creep resistance of the thin-walled Inconel 718 bill of material. Durability predictions are presented in terms of the probability of survival. A benchmark structural testing program has commenced to support the analyses. This report presents the current status of durability assessments.

  18. Advanced radioisotope power source options for Pluto Express

    SciTech Connect

    Underwood, M.L.

    1995-12-31

    In the drive to reduce mass and cost, Pluto Express is investigating using an advanced power conversion technology in a small Radioisotope Power Source (RPS) to deliver the required mission power of 74 W(electric) at end of mission. Until this year the baseline power source under consideration has been a Radioisotope Thermoelectric Generator (RTG). This RTG would be a scaled down GPHS RTG with an inventory of 6 General Purpose Heat Sources (GPHS) and a mass of 17.8 kg. High efficiency, advanced technology conversion options are being examined to lower the power source mass and to reduce the amount of radioisotope needed. Three technologies are being considered as the advanced converter technology: the Alkali Metal Thermal-to-Electric Converter (AMTEC), Thermophotovoltaic (TPV) converters, and Stirling Engines. Conceptual designs for each of these options have been prepared. Each converter would require only 2 GPHSs to provide the mission power and would have a mass of 6.1, 7.2, and 12.4 kg for AMTEC, TPV, and Stirling Engines respectively. This paper reviews the status of each technology and the projected performance of an advanced RPS based on each technology. Based on the projected performance and spacecraft integration issues, Pluto Express would prefer to use the AMTEC based RPS. However, in addition to technical performance, selection of a power technology will be based on many other factors.

  19. Radioisotopes: Today's Applications.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Nuclear Energy Office.

    Radioisotopes are useful because of their three unique characteristics: (1) radiation emission; (2) predictable radioactive lives; and (3) the same chemical properties as the nonradioactive atoms of that element. Researchers are able to "order" a radioisotope with the right radiation, half-life, and chemical property to perform a given task with…

  20. A Stirling Idea

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Stirling Technology Company developed the components for its BeCOOL line of Cryocoolers with the help of a series of NASA SBIRs (Small Business Innovative Research), through Goddard Space Flight Center and Marshall Space Flight Center. Features include a hermetically sealed design, compact size, and silent operation. The company has already placed several units with commercial customers for computer applications and laboratory use.

  1. Stirling in Another Context.

    ERIC Educational Resources Information Center

    Papademetriou, Peter

    1981-01-01

    An analysis and a critique of how remodeling and extension of the Rice University School of Architecture, by James Stirling, Michael Wilford, and Associates, fits into the campus plan and its eclectic style established early in this century. (Author/MLF)

  2. Stirling cycle piston engine

    SciTech Connect

    Morgan, G. R.

    1985-02-12

    This device is an improvement over the conventional type of Stirling cycle engine where the expander piston is connected to a crankshaft and the displacer piston is connected to the same or another crankshaft for operation. The improvement is based on both the expansion and displacer pistons being an integral unit having regenerating means which eliminate the mechanisms that synchronize the regeneration mode.

  3. The Stirling engine

    NASA Astrophysics Data System (ADS)

    This video describes the Stirling engine, an external combustion engine which creates heat energy to power the motor, and can use many types of fuel. It can be used for both stationary and propulsion purposes and has advantages of better fuel economy and cleaner exhaust than internal combustion engines. The engine is shown being road tested at Langley Air Force Base.

  4. Stirling machine operating experience

    SciTech Connect

    Ross, B.; Dudenhoefer, J.E.

    1994-09-01

    Numerous Stirling machines have been built and operated, but the operating experience of these machines is not well known. It is important to examine this operating experience in detail, because it largely substantiates the claim that stirling machines are capable of reliable and lengthy operating lives. The amount of data that exists is impressive, considering that many of the machines that have been built are developmental machines intended to show proof of concept, and are not expected to operate for lengthy periods of time. Some Stirling machines (typically free-piston machines) achieve long life through non-contact bearings, while other Stirling machines (typically kinematic) have achieved long operating lives through regular seal and bearing replacements. In addition to engine and system testing, life testing of critical components is also considered. The record in this paper is not complete, due to the reluctance of some organizations to release operational data and because several organizations were not contacted. The authors intend to repeat this assessment in three years, hoping for even greater participation.

  5. Stirling engine piston ring

    DOEpatents

    Howarth, Roy B.

    1983-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  6. Lunar Surface Stirling Power Systems Using Isotope Heat Sources

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Penswick, L. Barry; Shaltens, Richard K.

    2010-01-01

    For many years, NASA has used the decay of plutonium-238 (Pu-238) (in the form of the General Purpose Heat Source (GPHS)) as a heat source for Radioisotope Thermoelectric Generators (RTGs), which have provided electrical power for many NASA missions. While RTGs have an impressive reliability record for the missions in which they have been used, their relatively low thermal to electric conversion efficiency and the scarcity of plutonium-238 (Pu-238) has led NASA to consider other power conversion technologies. NASA is considering returning both robotic and human missions to the lunar surface and, because of the long lunar nights (14.75 Earth days), isotope power systems are an attractive candidate to generate electrical power. NASA is currently developing the Advanced Stirling Radioisotope Generator (ASRG) as a candidate higher efficiency power system that produces greater than 160 W with two GPHS modules at the beginning of life (BOL) (32% efficiency). The ASRG uses the same Pu-238 GPHS modules, which are used in RTG, but by coupling them to a Stirling convertor provides a four-fold reduction in the number of GPHS modules. This study considers the use of americium-241 (Am-241) as a substitute for the Pu-238 in Stirling- convertor-based Radioisotope Power Systems (RPS) for power levels from tens of watts to 5 kWe. The Am-241 is used as a substitute for the Pu-238 in GPHS modules. Depending on power level, different Stirling heat input and removal systems are modeled. It was found that substituting Am-241 GPHS modules into the ASRG reduces power output by about one-fifth while maintaining approximately the same system mass. In order to obtain the nominal 160 W of electrical output of the Pu-238 ASRG requires 10 Am-241 GPHS modules. Higher power systems require changing from conductive coupling heat input and removal from the Stirling convertor to either pumped loops or heat pipes. Liquid metal pumped loops are considered as the primary heat transportation on the hot

  7. Lunar Surface Stirling Power Systems Using Am-241

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Penswick, L. Barry; Shaltens, Richard K.

    2009-01-01

    For many years NASA has used the decay of Pu-238 (in the form of the General Purpose Heat Source (GPHS)) as a heat source for Radioisotope Thermoelectric Generators (RTG), which have provided electrical power for many NASA missions. While RTG's have an impressive reliability record for the missions in which they have been used, their relatively low thermal to electric conversion efficiency (-5% efficiency) and the scarcity of Plutoinium-238 (Pu-238) has led NASA to consider other power conversion technologies. NASA is considering returning both robotic and human missions to the lunar surface and, because of the long lunar nights (14 earth days) isotope power systems are an attractive candidate to generate electrical power. NASA is currently developing the Advanced Stirling Radioisotope Generator (ASRG) as a candidate higher efficiency power system that produces greater than 160 watts with 2 GPHS modules at the beginning of life (BOL) (-30% efficiency). The ASRG uses the same Pu-238 GPHS modules, which are used in RTG, but by coupling them to a Stirling convertor provides a 4-fold reduction in the number of GPHS modules. This study considers the use of Americium 241 (Am-241) as a substitute for the Pu-238 in Stirling convertor based Radioisotope Power Systems (RPS) for power levels from 1 O's of watts to 5 kWe. The Am-241 is used as a replacement for the Pu-238 in GPHS modules. Depending on power level, different Stirling heat input and removal systems are modeled. It was found that substituting Am-241 GPHS modules into the ASRG reduces power output by about 1/5 while maintaining approximately the same system mass. In order to obtain the nominal 160 watts electrical output of the Pu-238 ASRG requires 10 Am-241 GPHS modules. Higher power systems require changing from conductive coupling heat input and removal from the Stirling convertor to either pumped loops or heat pipes. Liquid metal pumped loops are considered as the primary heat transportation on the hot end and

  8. NASA's Advanced Radioisotope Power Conversion Technology Development Status

    NASA Technical Reports Server (NTRS)

    Anderson, David J.; Sankovic, John; Wilt, David; Abelson, Robert D.; Fleurial, Jean-Pierre

    2007-01-01

    NASA's Advanced Radioisotope Power Systems (ARPS) project is developing the next generation of radioisotope power conversion technologies that will enable future missions that have requirements that cannot be met by either photovoltaic systems or by current radioisotope power systems (RPSs). Requirements of advanced RPSs include high efficiency and high specific power (watts/kilogram) in order to meet future mission requirements with less radioisotope fuel and lower mass so that these systems can meet requirements for a variety of future space applications, including continual operation surface missions, outer-planetary missions, and solar probe. These advances would enable a factor of 2 to 4 decrease in the amount of fuel required to generate electrical power. Advanced RPS development goals also include long-life, reliability, and scalability. This paper provides an update on the contractual efforts under the Radioisotope Power Conversion Technology (RPCT) NASA Research Announcement (NRA) for research and development of Stirling, thermoelectric, and thermophotovoltaic power conversion technologies. The paper summarizes the current RPCT NRA efforts with a brief description of the effort, a status and/or summary of the contractor's key accomplishments, a discussion of upcoming plans, and a discussion of relevant system-level benefits and implications. The paper also provides a general discussion of the benefits from the development of these advanced power conversion technologies and the eventual payoffs to future missions (discussing system benefits due to overall improvements in efficiency, specific power, etc.).

  9. Stirling Convertor Control for a Concept Rover at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Blaze-Dugala, Gina M.

    2009-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Space Systems Company (LMSSC), Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for potential use as an electric power system for space science missions. This generator would make use of the free-piston Stirling cycle to achieve higher conversion efficiency than currently used alternatives. NASA GRC initiated an experiment with an ASRG simulator to demonstrate the functionality of a Stirling convertor on a mobile application, such as a rover. The ASRG simulator made use of two Advanced Stirling Convertors to convert thermal energy from a heat source to electricity. The ASRG simulator was designed to incorporate a minimum amount of support equipment, allowing integration onto a rover powered directly by the convertors. Support equipment to provide control was designed including a linear AC regulator controller, constant power controller, and Li-ion battery charger controller. The ASRG simulator is controlled by a linear AC regulator controller. The rover is powered by both a Stirling convertor and Li-ion batteries. A constant power controller enables the Stirling convertor to maintain a constant power output when additional power is supplied by the Li-ion batteries. A Li-ion battery charger controller limits the charging current and cut off current of the batteries. This paper discusses the design, fabrication, and implementation of these three controllers.

  10. Automotive Stirling engine development program

    NASA Technical Reports Server (NTRS)

    Farrell, R.; Hindes, C.; Battista, R.; Connelly, M.; Cronin, M.; Howarth, R.; Donahue, A.; Slate, E.; Stotts, R.; Lacy, R.

    1988-01-01

    The study of high power kinematic Stirling engines for transportation use, testing of Mod I and Mod II Stirling engines, and component development activities are summarized. Mod II development testing was performed to complete the development of the basic engine and begin characterization of performance. Mod I engines were used for Mod II component development and to obtain independent party (U.S. Air Force) evaluation of Stirling engine vehicle performance.

  11. NASA GRC Stirling Power Overview

    NASA Technical Reports Server (NTRS)

    Cornell, Peggy A.

    2014-01-01

    Current Project Thrusts - ASRG Transition to SRG Pathfinder; Government Furnished Services for ASRG; ASRG Engineering Unit 2; Planned Generator System Testing; Current Project Thrusts - Nuclear Systems; Fission Power Systems (FPS); Technology Demonstration Unit (TDU); Power Conversion Unit (PCU); Current Thrusts - KiloPower; Demonstrations Using Flattop Fissions (DUFF); Kilopower Reactor Using Stirling Technology (KRUSTY); Stirling Research - Hot End Components; Cold End Components; Stirling Testbeds; SBIRs

  12. Small Stirling dynamic isotope power system for robotic space missions

    NASA Technical Reports Server (NTRS)

    Bents, D. J.

    1992-01-01

    The design of a multihundred-watt Dynamic Isotope Power System (DIPS), based on the U.S. Department of Energy (DOE) General Purpose Heat Source (GPHS) and small (multihundred-watt) free-piston Stirling engine (FPSE), is being pursued as a potential lower cost alternative to radioisotope thermoelectric generators (RTG's). The design is targeted at the power needs of future unmanned deep space and planetary surface exploration missions ranging from scientific probes to Space Exploration Initiative precursor missions. Power level for these missions is less than a kilowatt. The incentive for any dynamic system is that it can save fuel and reduce costs and radiological hazard. Unlike DIPS based on turbomachinery conversion (e.g. Brayton), this small Stirling DIPS can be advantageously scaled to multihundred-watt unit size while preserving size and mass competitiveness with RTG's. Stirling conversion extends the competitive range for dynamic systems down to a few hundred watts--a power level not previously considered for dynamic systems. The challenge for Stirling conversion will be to demonstrate reliability and life similar to RTG experience. Since the competitive potential of FPSE as an isotope converter was first identified, work has focused on feasibility of directly integrating GPHS with the Stirling heater head. Thermal modeling of various radiatively coupled heat source/heater head geometries has been performed using data furnished by the developers of FPSE and GPHS. The analysis indicates that, for the 1050 K heater head configurations considered, GPHS fuel clad temperatures remain within acceptable operating limits. Based on these results, preliminary characterizations of multihundred-watt units have been established.

  13. Small Stirling dynamic isotope power system for robotic space missions

    NASA Astrophysics Data System (ADS)

    Bents, D. J.

    1992-08-01

    The design of a multihundred-watt Dynamic Isotope Power System (DIPS), based on the U.S. Department of Energy (DOE) General Purpose Heat Source (GPHS) and small (multihundred-watt) free-piston Stirling engine (FPSE), is being pursued as a potential lower cost alternative to radioisotope thermoelectric generators (RTG's). The design is targeted at the power needs of future unmanned deep space and planetary surface exploration missions ranging from scientific probes to Space Exploration Initiative precursor missions. Power level for these missions is less than a kilowatt. The incentive for any dynamic system is that it can save fuel and reduce costs and radiological hazard. Unlike DIPS based on turbomachinery conversion (e.g. Brayton), this small Stirling DIPS can be advantageously scaled to multihundred-watt unit size while preserving size and mass competitiveness with RTG's. Stirling conversion extends the competitive range for dynamic systems down to a few hundred watts--a power level not previously considered for dynamic systems. The challenge for Stirling conversion will be to demonstrate reliability and life similar to RTG experience. Since the competitive potential of FPSE as an isotope converter was first identified, work has focused on feasibility of directly integrating GPHS with the Stirling heater head. Thermal modeling of various radiatively coupled heat source/heater head geometries has been performed using data furnished by the developers of FPSE and GPHS. The analysis indicates that, for the 1050 K heater head configurations considered, GPHS fuel clad temperatures remain within acceptable operating limits. Based on these results, preliminary characterizations of multihundred-watt units have been established.

  14. Variable Conductance Heat Pipe Cooling of Stirling Convertor and General Purpose Heat Source

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Schwendeman, Carl; Anderson, William G.; Cornell, Peggy A.; Schifer, Nicholas A.

    2013-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 degC temperature increase from the nominal vapor temperature. The 19 degC temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental

  15. Radioisotope Electric Propulsion (REP): A Near-Term Approach to Nuclear Propulsion

    NASA Technical Reports Server (NTRS)

    Schmidt, George R.; Manzella, David H.; Kamhawi, Hani; Kremic, Tibor; Oleson, Steven R.; Dankanich, John W.; Dudzinski, Leonard A.

    2009-01-01

    Studies over the last decade have shown radioisotope-based nuclear electric propulsion to be enhancing and, in some cases, enabling for many potential robotic science missions. Also known as radioisotope electric propulsion (REP), the technology offers the performance advantages of traditional reactor-powered electric propulsion (i.e., high specific impulse propulsion at large distances from the Sun), but with much smaller, affordable spacecraft. Future use of REP requires development of radioisotope power sources with system specific powers well above that of current systems. The US Department of Energy and NASA have developed an advanced Stirling radioisotope generator (ASRG) engineering unit, which was subjected to rigorous flight qualification-level tests in 2008, and began extended lifetime testing later that year. This advancement, along with recent work on small ion thrusters and life extension technology for Hall thrusters, could enable missions using REP sometime during the next decade.

  16. Radioisotope electric propulsion (REP): A near-term approach to nuclear propulsion

    NASA Astrophysics Data System (ADS)

    Schmidt, George R.; Manzella, David H.; Kamhawi, Hani; Kremic, Tibor; Oleson, Steven R.; Dankanich, John W.; Dudzinski, Leonard A.

    2010-02-01

    Studies over the last decade have shown radioisotope-based nuclear electric propulsion to be enhancing and, in some cases, enabling for many potential robotic science missions. Also known as radioisotope electric propulsion (REP), the technology offers the performance advantages of traditional reactor-powered electric propulsion (i.e., high specific impulse propulsion at large distances from the Sun), but with much smaller, affordable spacecraft. Future use of REP requires development of radioisotope power sources with system specific powers well above that of current systems. The US Department of Energy and NASA have developed an advanced Stirling radioisotope generator (ASRG) engineering unit, which was subjected to rigorous flight qualification-level tests in 2008, and began extended lifetime testing later that year. This advancement, along with recent work on small ion thrusters and life extension technology for Hall thrusters, could enable missions using REP sometime during the next decade.

  17. Kuiper Belt Object Orbiter Using Advanced Radioisotope Power Sources and Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; McGuire, Melissa L.; Dankanich, John; Colozza, Anthony; Schmitz, Paul; Khan, Omair; Drexler, Jon; Fittje, James

    2011-01-01

    A joint NASA GRC/JPL design study was performed for the NASA Radioisotope Power Systems Office to explore the use of radioisotope electric propulsion for flagship class missions. The Kuiper Belt Object Orbiter is a flagship class mission concept projected for launch in the 2030 timeframe. Due to the large size of a flagship class science mission larger radioisotope power system building blocks were conceptualized to provide the roughly 4 kW of power needed by the NEXT ion propulsion system and the spacecraft. Using REP the spacecraft is able to rendezvous with and orbit a Kuiper Belt object in 16 years using either eleven (no spare) 420 W advanced RTGs or nine (with a spare) 550 W advanced Stirling Radioisotope systems. The design study evaluated integrating either system and estimated impacts on cost as well as required General Purpose Heat Source requirements.

  18. Update on Extended Operation of Stirling Convertors in Thermal Vacuum at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.

    2006-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Space Systems (LMSS), Infinia Corporation, and NASA Glenn Research Center (GRC) have been developing a Stirling Radioisotope Generator (SRG) for use as a power system on space science missions. This generator would make use of Stirling cycle energy conversion to achieve higher efficiency than currently used alternatives. A test has been initiated at GRC to demonstrate functionality of Stirling conversion in a thermal vacuum environment over an extended period of time. The test article resembles the configuration of the SRG, but was designed without the requirement of low mass. Throughout the 8700 cumulative hours of operation, modifications to the supporting hardware were required to attain the desired operating conditions. These modifications, the status of testing, and the data recorded will be discussed in this paper.

  19. Small Stirling dynamic isotope power system for multihundred-watt robotic missions

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1991-01-01

    Free Piston Stirling Engine (FPSE) and linear alternator (LA) technology is combined with radioisotope heat sources to produce a compact dynamic isotope power system (DIPS) suitable for multihundred watt space application which appears competitive with advance radioisotope thermoelectric generators (RTGs). The small Stirling DIPS is scalable to multihundred watt power levels or lower. The FPSE/LA is a high efficiency convertor in sizes ranging from tens of kilowatts down to only a few watts. At multihundred watt unit size, the FPSE can be directly integrated with the General Purpose Heat Source (GPHS) via radiative coupling; the resulting dynamic isotope power system has a size and weight that compares favorably with the advanced modular (Mod) RTG, but requires less than a third the amount of isotope fuel. Thus the FPSE extends the high efficiency advantage of dynamic systems into a power range never previously considered competitive for DIPS. This results in lower fuel cost and reduced radiological hazard per delivered electrical watt.

  20. Small Stirling dynamic isotope power system for multihundred-watt robotic missions

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1991-01-01

    Free piston Stirling Engine (FPSE) and linear alternator (LA) technology is combined with radioisotope heat sources to produce a compact dynamic isotope power system (DIPS) suitable for multihundred watt space application which appears competitive with advanced radioisotope thermoelectric generators (RTGs). The small Stirling DIPS is scalable to multihundred watt power levels or lower. The FPSE/LA is a high efficiency convertor in sizes ranging from tens of kilowatts down to only a few watts. At multihundred watt unit size, the FPSE can be directly integrated with the General Purpose Heat Source (GPHS) via radiative coupling; the resulting dynamic isotope power system has a size and weight that compares favorably with the advanced modular (Mod) RTG, but requires less than a third the amount of isotope fuel. Thus the FPSE extends the high efficiency advantage of dynamic systems into a power range never previously considered competitive for DIPS. This results in lower fuel cost and reduced radiological hazard per delivered electrical watt.

  1. Small Stirling dynamic isotope power system for multihundred-watt robotic missions

    NASA Astrophysics Data System (ADS)

    Bents, David J.

    Free Piston Stirling Engine (FPSE) and linear alternator (LA) technology is combined with radioisotope heat sources to produce a compact dynamic isotope power system (DIPS) suitable for multihundred watt space application which appears competitive with advance radioisotope thermoelectric generators (RTGs). The small Stirling DIPS is scalable to multihundred watt power levels or lower. The FPSE/LA is a high efficiency convertor in sizes ranging from tens of kilowatts down to only a few watts. At multihundred watt unit size, the FPSE can be directly integrated with the General Purpose Heat Source (GPHS) via radiative coupling; the resulting dynamic isotope power system has a size and weight that compares favorably with the advanced modular (Mod) RTG, but requires less than a third the amount of isotope fuel. Thus the FPSE extends the high efficiency advantage of dynamic systems into a power range never previously considered competitive for DIPS. This results in lower fuel cost and reduced radiological hazard per delivered electrical watt.

  2. Performance of Stirling Engines

    NASA Astrophysics Data System (ADS)

    Iwamoto, Shoichi; Hirata, Koichi; Toda, Fujio

    We have developed five kinds of high- and low-temperature differential Stirling engines and their engine performance was investigated experimentally. In order to determine the parameters that affect engine performance, experimental results were discussed and compared with results calculated using analytical methods. We show an arranging method for the experimental results, and consider the performance of general Stirling engines. After using the arranging method with nondimensional numbers obtained by a dimensional analysis, a prediction method, which is used at the early design stage, is formulated. One of the nondimensional numbers in this prediction method is calculated based on engine specifications, including the properties of the working gas. The prediction method can predict engine speed, output power, the effect of working gas and operating conditions.

  3. Stirling cycle cryogenic cooler

    NASA Astrophysics Data System (ADS)

    Gasser, M. G.; Sherman, A.; Studer, P. A.; Daniels, A.; Goldowsky, M. P.

    1983-06-01

    A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications is described. It consists of a compressor section centrally aligned end to end with an expansion section, and respectively includes a reciprocating compressor piston and displacer radially suspended in interconnecting cylindrical housings by active magnetic bearings and has adjacent reduced clearance regions so as to be in noncontacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston and displacer are reciprocated in their housings by linear drive motors to vary the volume of respectively adjacent compression and expansion spaces which contain a gaseous working fluid and a thermal regenerator to effect Stirling cycle cryogenic cooling.

  4. Stirling cycle cryogenic cooler

    NASA Technical Reports Server (NTRS)

    Gasser, M. G.; Sherman, A.; Studer, P. A.; Daniels, A.; Goldowsky, M. P. (Inventor)

    1983-01-01

    A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications is described. It consists of a compressor section centrally aligned end to end with an expansion section, and respectively includes a reciprocating compressor piston and displacer radially suspended in interconnecting cylindrical housings by active magnetic bearings and has adjacent reduced clearance regions so as to be in noncontacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston and displacer are reciprocated in their housings by linear drive motors to vary the volume of respectively adjacent compression and expansion spaces which contain a gaseous working fluid and a thermal regenerator to effect Stirling cycle cryogenic cooling.

  5. Radioisotope power system options for future planetary missions

    NASA Astrophysics Data System (ADS)

    Cockfield, Robert D.

    2001-02-01

    Like previous missions to the outer planets, future spacecraft missions such as Pluto/Kuiper Express, Europa Orbiter, and Solar Probe will require radioisotope power systems for their long voyages away from the Sun. Several candidate advanced power conversion technologies have been proposed that have been proposed that have higher power conversion efficiencies than the traditional thermoelectric generators, with the potential for reduced mass and reduced quantities of nuclear fuel required. Studies conducted by Lockheed Martin under the direction of the Department of Energy have included the development of system conceptual designs utilizing Alkali Metal to Electric Conversion (AMTEC) and Stirling power conversion. Generator concepts based on these conversion technologies are compared in this paper with an alternative Small RTG, based on the General Purpose Heat Source-Radioisotope Thermoelectric Generator (GPHS-RTG). .

  6. Radioisotope Electric Propulsion for Fast Outer Planetary Orbiters

    NASA Technical Reports Server (NTRS)

    Oleson, Steven; Benson, Scott; Gefert, Leon; Patterson, Michael; Schreiber, Jeffrey

    2002-01-01

    Recent interest in outer planetary targets by the Office of Space Science has spurred the search for technology options to enable relatively quick missions to outer planetary targets. Several options are being explored including solar electric propelled stages combined with aerocapture at the target and nuclear electric propulsion. Another option uses radioisotope powered electric thrusters to reach the outer planets. Past work looked at using this technology to provide faster flybys. A better use for this technology is for outer planet orbiters. Combined with medium class launch vehicles and a new direct trajectory these small, sub-kilowatt ion thrusters and Stirling radioisotope generators were found to allow missions as fast as 5 to 12 years for objects from Saturn to Pluto, respectively. Key to the development is light spacecraft and science payload technologies.

  7. Outer Planet Exploration with Advanced Radioisotope Electric Propulsion

    NASA Technical Reports Server (NTRS)

    Oleson, Steven; Gefert, Leon; Patterson, Michael; Schreiber, Jeffrey; Benson, Scott; McAdams, Jim; Ostdiek, Paul

    2002-01-01

    In response to a request by the NASA Deep Space Exploration Technology Program, NASA Glenn Research Center conducted a study to identify advanced technology options to perform a Pluto/Kuiper mission without depending on a 2004 Jupiter Gravity Assist, but still arriving before 2020. A concept using a direct trajectory with small, sub-kilowatt ion thrusters and Stirling radioisotope power systems was shown to allow the same or smaller launch vehicle class as the chemical 2004 baseline and allow a launch slip and still flyby in the 2014 to 2020 timeframe. With this promising result the study was expanded to use a radioisotope power source for small electrically propelled orbiter spacecraft for outer planet targets such as Uranus, Neptune, and Pluto.

  8. Stirling engine power control

    DOEpatents

    Fraser, James P.

    1983-01-01

    A power control method and apparatus for a Stirling engine including a valved duct connected to the junction of the regenerator and the cooler and running to a bypass chamber connected between the heater and the cylinder. An oscillating zone of demarcation between the hot and cold portions of the working gas is established in the bypass chamber, and the engine pistons and cylinders can run cold.

  9. Stirling cycle engine

    DOEpatents

    Lundholm, Gunnar

    1983-01-01

    In a Stirling cycle engine having a plurality of working gas charges separated by pistons reciprocating in cylinders, the total gas content is minimized and the mean pressure equalization among the serial cylinders is improved by using two piston rings axially spaced at least as much as the piston stroke and by providing a duct in the cylinder wall opening in the space between the two piston rings and leading to a source of minimum or maximum working gas pressure.

  10. Radioisotopic heat source

    DOEpatents

    Sayell, E.H.

    1973-10-23

    A radioisotopic heat source is described which includes a core of heat productive, radioisotopic material, an impact resistant layer of graphite surrounding said core, and a shell of iridium metal intermediate the core and the impact layer. The source may also include a compliant mat of iridium between the core and the iridium shell, as well as an outer covering of iridium metal about the entire heat source. (Official Gazette)

  11. Stirling engine design manual

    NASA Technical Reports Server (NTRS)

    Martini, W. R.

    1978-01-01

    This manual is intended to serve both as an introduction to Stirling engine analysis methods and as a key to the open literature on Stirling engines. Over 800 references are listed and these are cross referenced by date of publication, author and subject. Engine analysis is treated starting from elementary principles and working through cycles analysis. Analysis methodologies are classified as first, second or third order depending upon degree of complexity and probable application; first order for preliminary engine studies, second order for performance prediction and engine optimization, and third order for detailed hardware evaluation and engine research. A few comparisons between theory and experiment are made. A second order design procedure is documented step by step with calculation sheets and a worked out example to follow. Current high power engines are briefly described and a directory of companies and individuals who are active in Stirling engine development is included. Much remains to be done. Some of the more complicated and potentially very useful design procedures are now only referred to. Future support will enable a more thorough job of comparing all available design procedures against experimental data which should soon be available.

  12. Automotive Stirling engine development program

    NASA Technical Reports Server (NTRS)

    Ernst, W.; Piller, S.; Richey, A.; Simetkosky, M.; Antonelli, M. (Editor)

    1982-01-01

    Activities performed on Mod I engine testing and test results, progress in manufacturing, assembling and testing of a Mod I engine in the United States, P40 Stirling engine dynamometer and multifuels testing, analog/digital controls system testing, Stirling reference engine manufacturing and reduced size studies, components and subsystems, and computer code development are summarized.

  13. Automotive Stirling Engine Development Program

    NASA Technical Reports Server (NTRS)

    Allen, M. (Editor)

    1980-01-01

    Progress is reported in the following: the Stirling reference engine system design; components and subsystems; F-40 baseline Stirling engine installation and test; the first automotive engine to be built on the program; computer development activities; and technical assistance to the Government. The overall program philosophy is outlined, and data and results are given.

  14. Status of NASA's Advanced Radioisotope Power Conversion Technology Research and Development

    NASA Astrophysics Data System (ADS)

    Wong, Wayne A.; Anderson, David J.; Tuttle, Karen L.; Tew, Roy C.

    2006-01-01

    NASA's Advanced Radioisotope Power Systems (RPS) development program is funding the advancement of next generation power conversion technologies that will enable future missions that have requirements that can not be met by either the ubiquitous photovoltaic systems or by current Radioisotope Power Systems (RPS). Requirements of advanced radioisotope power systems include high efficiency and high specific power (watts/kilogram) in order to meet mission requirements with less radioisotope fuel and lower mass. Other Advanced RPS development goals include long-life, reliability, and scalability so that these systems can meet requirements for a variety of future space applications including continual operation surface missions, outer-planetary missions, and solar probe. This paper provides an update on the Radioisotope Power Conversion Technology Project which awarded ten Phase I contracts for research and development of a variety of power conversion technologies consisting of Brayton, Stirling, thermoelectrics, and thermophotovoltaics. Three of the contracts continue during the current Phase II in the areas of thermoelectric and Stirling power conversion. The accomplishments to date of the contractors, project plans, and status will be summarized.

  15. Status of NASA's Advanced Radioisotope Power Conversion Technology Research and Development

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Anderson, David J.; Tuttle, Karen L.; Tew, Roy C.

    2006-01-01

    NASA s Advanced Radioisotope Power Systems (RPS) development program is funding the advancement of next generation power conversion technologies that will enable future missions that have requirements that can not be met by either the ubiquitous photovoltaic systems or by current Radioisotope Power Systems (RPS). Requirements of advanced radioisotope power systems include high efficiency and high specific power (watts/kilogram) in order to meet mission requirements with less radioisotope fuel and lower mass. Other Advanced RPS development goals include long-life, reliability, and scalability so that these systems can meet requirements for a variety of future space applications including continual operation surface missions, outer-planetary missions, and solar probe. This paper provides an update on the Radioisotope Power Conversion Technology Project which awarded ten Phase I contracts for research and development of a variety of power conversion technologies consisting of Brayton, Stirling, thermoelectrics, and thermophotovoltaics. Three of the contracts continue during the current Phase II in the areas of thermoelectric and Stirling power conversion. The accomplishments to date of the contractors, project plans, and status will be summarized.

  16. Fabrication and Testing of a Thin-Film Heat Flux Sensor for a Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.; Fralick, Gustave; Wrbanek, John; Sayir, Ali

    2009-01-01

    The NASA Glenn Research Center (GRC) has been testing high efficiency free-piston Stirling convertors for potential use in radioisotope power systems since 1999. Stirling convertors are being operated for many years to demonstrate a radioisotope power system capable of providing reliable power for potential multi-year missions. Techniques used to monitor the convertors for change in performance include measurements of temperature, pressure, energy addition, and energy rejection. Micro-porous bulk insulation is used in the Stirling convertor test set up to minimize the loss of thermal energy from the electric heat source to the environment. The insulation is characterized before extended operation, enabling correlation of the net thermal energy addition to the convertor. Aging microporous bulk insulation changes insulation efficiency, introducing errors in the correlation for net thermal energy addition. A thin-mm heat flux sensor was designed and fabricated to directly measure the net thermal energy addition to the Stirling convertor. The fabrication techniques include slip casting and using Physical Vapor Deposition (PVD). One micron thick noble metal thermocouples measure temperature on the surface of an Alumina ceramic disc and heat flux is calculated. Fabrication, integration, and test results of a thin film heat flux sensor are presented.

  17. Fabrication and Testing of a Thin-Film Heat Flux Sensor for a Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.; Fralick, Gus c.; Wrbanek, John D.; Sayir, Ali

    2010-01-01

    The NASA Glenn Research Center (GRC) has been testing high-efficiency free-piston Stirling convertors for potential use in radioisotope power systems since 1999. Stirling convertors are being operated for many years to demonstrate a radioisotope power system capable of providing reliable power for potential multiyear missions. Techniques used to monitor the convertors for change in performance include measurements of temperature, pressure, energy addition, and energy rejection. Micro-porous bulk insulation is used in the Stirling convertor test setup to minimize the loss of thermal energy from the electric heat source to the environment. The insulation is characterized before extended operation, enabling correlation of the net thermal energy addition to the convertor. Aging micro-porous bulk insulation changes insulation efficiency, introducing errors in the correlation for net thermal energy addition. A thin-film heat flux sensor was designed and fabricated to directly measure the net thermal energy addition to the Stirling convertor. The fabrication techniques include slipcasting and using Physical Vapor Deposition (PVD). One-micron-thick noble metal thermocouples measure temperature on the surface of an alumina ceramic disk and heat flux is calculated. Fabrication, integration, and test results of a thin-film heat flux sensor are presented.

  18. Performance of an Advanced Stirling Convertor Based on Heat Flux Sensor Measurements

    NASA Technical Reports Server (NTRS)

    Wilson, Dcott D.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two highefficiency Advanced Stirling Convertors (ASCs), developed by Sunpower, Inc., and NASA Glenn Research Center. The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot-end and cold-end temperatures, and specified electrical power output for a given heat input. It is difficult to measure heat input to Stirling convertors due to the complex geometries of the hot components, temperature limits of sensor materials, and invasive integration of sensors. A thin-film heat flux sensor was used to directly measure heat input to an ASC. The effort succeeded in designing and fabricating unique sensors, which were integrated into a Stirling convertor ground test and exposed to test temperatures exceeding 700 C in air for 10,000 hr. Sensor measurements were used to calculate thermal efficiency for ASC-E (Engineering Unit) #1 and #4. The post-disassembly condition of the sensors is also discussed.

  19. Performance of an Advanced Stirling Convertor Based on Heat Flux Sensor Measurements

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two high-efficiency Advanced Stirling Convertors (ASCs), developed by Sunpower, Inc., and NASA Glenn Research Center. The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot-end and cold-end temperatures, and specified electrical power output for a given heat input. It is difficult to measure heat input to Stirling convertors due to the complex geometries of the hot components, temperature limits of sensor materials, and invasive integration of sensors. A thin-film heat flux sensor was used to directly measure heat input to an ASC. The effort succeeded in designing and fabricating unique sensors, which were integrated into a Stirling convertor ground test and exposed to test temperatures exceeding 700 C in air for 10,000 hr. Sensor measurements were used to calculate thermal efficiency for ASC-E (Engineering Unit) #1 and #4. The post-disassembly condition of the sensors is also discussed.

  20. Supporting Technology at GRC to Mitigate Risk as Stirling Power Conversion Transitions to Flight

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.; Wong, Wayne A.

    2008-01-01

    Stirling power conversion technology has been reaching more advanced levels of maturity during its development for space power applications. The current effort is in support of the Advanced Stirling Radioisotope Generator (ASRG), which is being developed by the U.S. Department of Energy (DOE), Lockheed Martin Space Systems Company (LMSSC), Sunpower Inc., and the NASA Glenn Research Center (GRC). This generator would use two high-efficiency Advanced Stirling Convertors (ASCs) to convert thermal energy from a radioisotope heat source into electricity. Of paramount importance is the reliability of the power system and as a part of this, the Stirling power convertors. GRC has established a supporting technology effort with tasks in the areas of reliability, convertor testing, high-temperature materials, structures, advanced analysis, organics, and permanent magnets. The project utilizes the matrix system at GRC to make use of resident experts in each of the aforementioned fields. Each task is intended to reduce risk and enhance reliability of the convertor as this technology transitions toward flight status. This paper will provide an overview of each task, outline the recent efforts and accomplishments, and show how they mitigate risk and impact the reliability of the ASC s and ultimately, the ASRG.

  1. Supporting Technology at GRC to Mitigate Risk as Stirling Power Conversion Transitions to Flight

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.; Wong, Wayne A.

    2009-01-01

    Stirling power conversion technology has been reaching more advanced levels of maturity during its development for space power applications. The current effort is in support of the Advanced Stirling Radioisotope Generator (ASRG), which is being developed by the U.S. Department of Energy (DOE), Lockheed Martin Space Systems Company (LMSSC), Sunpower Inc., and the NASA Glenn Research Center (GRC). This generator would use two high-efficiency Advanced Stirling Convertors (ASCs) to convert thermal energy from a radioisotope heat source into electricity. Of paramount importance is the reliability of the power system and as a part of this, the Stirling power convertors. GRC has established a supporting technology effort with tasks in the areas of reliability, convertor testing, high-temperature materials, structures, advanced analysis, organics, and permanent magnets. The project utilizes the matrix system at GRC to make use of resident experts in each of the aforementioned fields. Each task is intended to reduce risk and enhance reliability of the convertor as this technology transitions toward flight status. This paper will provide an overview of each task, outline the recent efforts and accomplishments, and show how they mitigate risk and impact the reliability of the ASC s and ultimately, the ASRG.

  2. Stirling Powered Van Progam overview

    NASA Technical Reports Server (NTRS)

    Shaltens, R. K.

    1986-01-01

    The Stirling Powered Van Program (SPVP) is a multiyear, multiphase program to evaluate the automotive Stirling engine (ASE) in Air Force vans under realistic conditions. The objective of the SPVP is to transfer to manufacturer and end user(s) (i.e., on the path to commercialization) the second-generation Mod 2 ASE upon completion of the Automotive Stirling Engine Program in 1987. In order to meet this objective, the SPVP must establish Stirling performance, integrity, reliability, durability and maintainability. The ASE program background leading to the van program is reviewed and plans for evaluating the kinematic Stirling engine in Air Force vans examined. Also discussed are the NASA technology transfers to industry that have been accomplished and those which are currently being developed.

  3. Processing and Preparation of Advanced Stirling Convertors for Extended Operation

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Cornell, Paggy A.

    2008-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Space Company (LMSC), Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for use as a power system on space science missions. This generator will make use of the free-piston Stirling convertors to achieve higher conversion efficiency than currently available alternatives. NASA GRC is supporting the development of the ASRG by providing extended operation of several Sunpower Inc. Advanced Stirling Convertors (ASCs). In the past year and a half, eight ASCs have operated in continuous, unattended mode in both air and thermal vacuum environments. Hardware, software, and procedures were developed to prepare each convertor for extended operation with intended durations on the order of tens of thousands of hours. Steps taken to prepare a convertor for long-term operation included geometry measurements, thermocouple instrumentation, evaluation of working fluid purity, evacuation with bakeout, and high purity charge. Actions were also taken to ensure the reliability of support systems, such as data acquisition and automated shutdown checkouts. Once a convertor completed these steps, it underwent short-term testing to gather baseline performance data before initiating extended operation. These tests included insulation thermal loss characterization, low-temperature checkout, and full-temperature and power demonstration. This paper discusses the facilities developed to support continuous, unattended operation, and the processing results of the eight ASCs currently on test.

  4. Advanced Stirling Convertor (ASC) Technology Maturation in Preparation for Flight

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Cornell, Peggy A.

    2012-01-01

    The Advanced Stirling Convertor (ASC) is being developed by an integrated team of Sunpower and National Aeronautics and Space Administration s (NASA s) Glenn Research Center (GRC). The ASC development, funded by NASA s Science Mission Directorate, started as a technology development effort in 2003 and has since evolved through progressive convertor builds and successful testing to demonstrate high conversion efficiency, low mass, and capability to meet long-life Radioisotope Power System (RPS) requirements. The technology has been adopted by the Department of Energy and Lockheed Martin Space Systems Company s Advanced Stirling Radioisotope Generator (ASRG), which has been selected for potential flight demonstration on Discovery 12. This paper provides an overview of the status of ASC development including the most recent ASC-E2 convertors that have been delivered to GRC and an introduction to the ASC-E3 and ASC flight convertors that Sunpower will build next. The paper also describes the technology maturation and support tasks being conducted at GRC to support ASC and ASRG development in the areas of convertor and generator extended operation, high-temperature materials, heater head life assessment, organics, nondestructive inspection, spring fatigue testing, and other reliability verification tasks.

  5. Continued Development of the Advanced Stirling Convertor (ASC)

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Wood, J. Gary; Wilson, Kyle; Buffalino, Andrew; Frye, Patrick; Matejczyk, Dan; Penswick, L.B.

    2008-01-01

    The Advanced Stirling Convertor (ASC) is being developed under contract with the NASA Glenn Research Center (GRC) and is supported by NASA s Science Mission Directorate for potential use in future radioisotope power systems having significantly increased efficiency and higher specific power compared to the current thermoelectric systems. An ASC with a lower temperature (approx.650 C) Inconel heater head is currently being substituted into the DOE/Lockheed Martin Advanced Stirling Radioisotope Generator (ASRG) program with a predicted convertor efficiency of 34 percent (AC electrical out to heat input ) at a temperature ratio of 2.7 and is expected to deliver approximately 75 W(sub ac). Continued development of the higher temperature (approx.850 C) version using existing materials and fabrication techniques in the hot portions is reported on here. The higher temperature ASC is expected to have 38 percent efficiency (AC electrical out to heat input) at a temperature ratio of 3.1 and is expected to deliver approximately 88 W(sub ac). The high temperature ASC also has approximately 30 C higher rejection temperature, which allows for further reduced system mass because of the reduced radiator size. Six higher temperature and hermetically sealed convertors are being built under this effort for extended life testing at GRC.

  6. Advanced Stirling Technology Development at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Wong, Wayne A.

    2007-01-01

    The NASA Glenn Research Center has been developing advanced energy-conversion technologies for use with both radioisotope power systems and fission surface power systems for many decades. Under NASA's Science Mission Directorate, Planetary Science Theme, Technology Program, Glenn is developing the next generation of advanced Stirling convertors (ASCs) for use in the Department of Energy/Lockheed Martin Advanced Stirling Radioisotope Generator (ASRG). The next-generation power-conversion technologies require high efficiency and high specific power (watts electric per kilogram) to meet future mission requirements to use less of the Department of Energy's plutonium-fueled general-purpose heat source modules and reduce system mass. Important goals include long-life (greater than 14-yr) reliability and scalability so that these systems can be considered for a variety of future applications and missions including outer-planet missions and continual operation on the surface of Mars. This paper provides an update of the history and status of the ASC being developed for Glenn by Sunpower Inc. of Athens, Ohio.

  7. Overview of NASA GRC Stirling Technology Development

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.

    2004-01-01

    The Stirling Radioisotope Generator (SRG) is currently being developed by Lockheed Martin Astronautics (LMA) under contract to the Department of Energy (DOE). The generator will be a high efficiency electric power source for NASA Space Science missions with the ability to operate in vacuum or in an atmosphere such as on Mars. High efficiency is obtained through the use of free-piston Stirling power conversion. Power output will be greater than 100 watts at the beginning of life with the decline in power largely due to the decay of the plutonium heat source. In support of the DOE SRG project, the NASA Glenn Research Center (GRC) has established a technology effort to provide data to ensure a successful transition to flight for what will be the first dynamic power system in space. Initially, a limited number of areas were selected for the effort, however this is now being expanded to more thoroughly cover key technical issues. There is also an advanced technology effort that is complementary to the near-term technology effort. Many of the tests use the 55-We Technology Demonstration Convertor (TDC). There have been multiple controller tests to support the LMA flight controller design effort. Preparation is continuing for a thermal/vacuum system demonstration. A pair of flight prototype TDC s have been placed on continuous operation. Heater head life assessment continues, with the material data being refined and the analysis moving toward the system perspective. Magnet aging tests continue to characterize any possible aging in the strength or demagnetization resistance of the magnets in the linear alternator. A reliability effort has been initiated to help guide the development activities with focus on the key components and subsystems. This paper will provide an overview of some of the GRC technical efforts, including the status, and a description of future efforts.

  8. Advanced Stirling Convertor (ASC) Development for NASA RPS

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Wilson, Scott; Collins, Josh

    2014-01-01

    Sunpower's Advanced Stirling Convertor (ASC) initiated development under contract to the NASA Glenn Research Center (GRC) and after a series of successful demonstrations, the ASC began transitioning from a technology development project to flight development project. The ASC has very high power conversion efficiency making it attractive for future Radioisotope Power Systems (RPS) in order to make best use of the low plutonium-238 fuel inventory in the U.S. In recent years, the ASC became part of the NASA-Department of Energy Advanced Stirling Radioisotope Generator (ASRG) Integrated Project. Sunpower held two parallel contracts to produce ASC convertors, one with the Department of Energy/Lockheed Martin to produce the ASC-F flight convertors, and one with NASA GRC for the production of ASC-E3 engineering units, the initial units of which served as production pathfinders. The integrated ASC technical team successfully overcame various technical challenges that led to the completion and delivery of the first two pairs of flight-like ASC-E3 by 2013. However, in late Fall 2013, the DOE initiated termination of the Lockheed Martin ASRG flight development contract driven primarily by budget constraints. NASA continues to recognize the importance of high efficiency ASC power conversion for RPS and continues investment in the technology including the continuation of ASC-E3 production at Sunpower and the assembly of the ASRG Engineering Unit #2. This paper provides a summary of ASC technical accomplishments, overview of tests at GRC, plans for continued ASC production at Sunpower, and status of Stirling technology development.

  9. Assessment of dynamic energy conversion systems for radioisotope heat sources

    SciTech Connect

    Thayer, G.R.; Mangeng, C.A.

    1985-06-01

    The use of dynamic conversion systems to convert the heat generated in a 7500 W(t) 90 Sr radioisotopic heat source to electricity is examined. The systems studies were Stirling; Brayton Cycle; three organic Rankines (ORCs) (Barber-Nichols/ORMAT, Sundstrand, and TRW); and an organic Rankine plus thermoelectrics. The systems were ranked for a North Warning System mission using a Los Alamos Multiattribute Decision Theory code. Three different heat source designs were used: case I with a beginning of life (BOL) source temperature of 640 C, case II with a BOL source temperature of 745/sup 0/C, and case III with a BOL source temperature of 945/sup 0/C. The Stirling engine system was the top-ranked system of cases I and II, closely followed by the ORC systems in case I and ORC plus thermoelectrics in case II. The Brayton cycle system was top-ranked for case III, with the Stirling engine system a close second. The use of /sup 238/Pu in heat source sizes of 7500 W(t) was examined and found to be questionable because of cost and material availability and because of additional requirements for analysis of safeguards and critical mass.

  10. Assessment of dynamic energy conversion systems for radioisotope heat sources

    NASA Astrophysics Data System (ADS)

    Thayer, G. R.; Mangeng, C. A.

    1985-06-01

    The use of dynamic conversion systems to convert the heat generated in a 7500 W(t) 90 Sr radioisotopic heat source to electricity is examined. The systems studies were: Stirling; Brayton cycle; three organic Rankines (ORCs) (Barber-Nichols/ORMAT, Sundstrand, and TRW); and an organic Rankine plus thermoelectrics. The systems were ranked for a North Warning System mission using a Los Alamos multiattribute decision theory code. Three different heat source designs were used: case 1 with a beginning of life (BOL) source temperature of 640 C, case 2 with a BOL source temperature of 745 C, and case 3 with a BOL source temperature of 945 C. The Stirling engine system was the top-ranked system of case 1 and 2, closely followed by the ORC systems in case 1 and ORC plus thermoelectrics in case 2. The Brayton cycle system was top-ranked for case 3, with the Stirling engine system a close second. The use of (238) Pu in heat source sizes of 7500 W(t) is examined and it is found to be questionable because of cost and material availability and because of additional requirements for anlaysis of safeguards and critical mass.

  11. A 3-D Magnetic Analysis of a Stirling Convertor Linear Alternator Under Load

    NASA Technical Reports Server (NTRS)

    Geng, Steven M.; Schwarze, Gene E.; Niedra, Janis M.; Regan, Timothy F.

    2001-01-01

    The NASA Glenn Research Center (GRC), the Department of Energy (DOE), and the Stirling Technology Company (STC) are developing Stirling convertors for Stirling Radioisotope Power Systems (SRPS) to provide electrical power for future NASA deep space missions. STC is developing the 55-We Technology Demonstration Convertor (TDC) under contract to DOE. Of critical importance to the successful development of the Stirling convertor for space power applications is the development of a lightweight and highly efficient linear alternator. This paper presents a 3-dimensional finite element method (FEM) approach for evaluating Stirling convertor linear alternators. The model extends a magnetostatic analysis previously reported at the 35th Intersociety Energy Conversion Engineering Conference (IECEC) to include the effects of the load current. STC's 55-We linear alternator design was selected to validate the model. Spatial plots of magnetic field strength (H) are presented in the region of the exciting permanent magnets. The margin for permanent magnet demagnetization is calculated at the expected magnet operating temperature for the near earth environment and for various average magnet temperatures. These thermal conditions were selected to represent a worst-case condition for the planned deep space missions. This paper presents plots that identify regions of high H where the potential to alter the magnetic moment of the magnets exists.

  12. Progress in Developing a New 5 Kilowatt Free-Piston Stirling Space Convertor

    SciTech Connect

    Brandhorst, Henry W. Jr.; Kirby, Raymond L.; Chapman, Peter A.

    2008-01-21

    The NASA Vision for Exploration of the Moon envisions a nuclear reactor coupled with a free-piston Stirling convertor at a power level of 30-40 kWe. In the 1990s, Mechanical Technology, Inc.'s Stirling Engine Systems Division (now a part of Foster-Miller, Inc.) developed a 25 kWe free piston Stirling Space Power Demonstrator Engine under the SP-100 program. This system consisted of two 12.5 kWe engines connected at their hot ends and mounted in tandem to cancel vibration. Recently, NASA and DoE have been developing dual 55 We and 80 We Stirling convertor systems for use with radioisotope heat sources. Total test times of all convertors in this effort exceed 120,000 hours. Recently, NASA began a new project with Auburn University to develop a 5 kWe, single convertor for use in the Lunar power system. Goals of this development program include a specific power in excess of 140 We/kg at the convertor level, lifetime in excess of five years and a control system that will safely manage the convertors in case of an emergency. Auburn University awarded a subcontract to Foster-Miller, Inc. to undertake development of the 5 kWe Stirling Convertor Assembly. The characteristics of the design along with progress in developing the system will be described.

  13. Overview of NASA GRC Stirling Technology Development

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey; Thieme, Lanny

    2003-01-01

    The Stirling Radioisotope Generator (SRG) is currently being developed by Lockheed Martin Astronautics (LMA) under contract to the Depar1ment of Energy (DOE). The generator will be a high efficiency electric power source for NASA Space Science missions with the capability to operate in the vacuum of deep space or in an atmosphere such as on the surface of Mars. High system efficiency is obtained through the use of free-piston Stirling power conversion technology. Power output of the generator will be greater than 100 watts at the beginning of life with the decline in power being largely due to the decay of the plutonium heat source. In suppOl1 of the DOE SRG project, the NASA Glenn Research Center (GRC) has established a near-term technology effort to provide some of the critical data to ensure a successful transition to flight for what will be the first dynamic power system used in space. Initially, a limited number of technical areas were selected for the GRC effort, however this is now being expanded to more thoroughly cover a range of technical issues. The tasks include in-house testing of Stirling convertors and controllers, materials evaluation and heater head life assessment, structural dynamics, electromagnetic interference, organics evaluation, and reliability analysis. Most of these high-level tasks have several subtasks within. There is also an advanced technology effort that is complementary near-term technology effort. Many of the tests make use of the 55-We Technology Demonstration Convel10r (TDC). There have been multiple controller tests to support the LMA flight controller design effort. Preparation is continuing for a thermal/vacuum system demonstration. A pair of flight prototype TDC's have recently been placed on an extended test with unattended, continuous operation. Heater head life assessment efforts continue, with the material data being refined and the analysis moving toward the system perspective. Long-term magnet aging tests are

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

    NASA Technical Reports Server (NTRS)

    Anderson, David J.; Wong, Wayne A.; Tuttle, Karen L.

    2005-01-01

    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), August 13, 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. 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.

  15. A pistonless Stirling cooler

    NASA Astrophysics Data System (ADS)

    Yazaki, T.; Biwa, T.; Tominaga, A.

    2002-01-01

    We demonstrate a prototype acoustic cooler that uses Stirling cycles executed by a traveling wave with high acoustic impedance thermoacoustically induced in a looped tube. The tube has no moving parts, only a pair of stacks sandwiched between two heat exchangers: one amplifies the acoustic power and the amplified wave supplies the driving energy to pump heat directly within the second stack. Because it uses extremely simple hardware consisting of a few parts, the cooling device is potentially a powerful tool for applications such as conventional cooling systems.

  16. Stirling cycle machine

    SciTech Connect

    Burnett, S.C.; Purcell, J.R.; Creedon, W.P.; Joshi, C.H.

    1990-06-05

    This patent describes an improvement in a Stirling cycle machine including first and second variable-volume, compression-expansion chambers containing a gas a regenerator interconnecting the chambers and for conducting the gas therebetween, and eccentric drive means for driving the first and second chambers. It comprises: the eccentric drive means comprising a pair of rotatably mounted shafts, at least one pair of eccentric disks fixed on the shafts in phase with each other, and means for causing the shafts and thereby the eccentric disks to rotate in opposite directions.

  17. Performance tuned radioisotope thermophotovoltaic space power system

    NASA Astrophysics Data System (ADS)

    Horne, W. E.; Morgan, M. D.; Saban, S. B.

    1998-01-01

    The trend in space exploration is to use many small, low-cost, special-purpose satellites instead of the large, high-cost, multipurpose satellites used in the past. As a result of this new trend, there is a need for lightweight, efficient, and compact radioisotope fueled electrical power generators. This paper presents an improved design for a radioisotope thermophotovoltaic (RTPV) space power system in the 10 W to 20 W class which promises up to 37.6 watts at 30.1% efficiency and 25 W/kg specific power. The RTPV power system concept has been studied and compared to radioisotope thermoelectric generators (RTG) radioisotope, Stirling generators and alkali metal thermal electric conversion (AMTEC) generators (Schock, 1995). The studies indicate that RTPV has the potential to be the lightest weight, most efficient and most reliable of the three concepts. However, in spite of the efficiency and light weight, the size of the thermal radiator required to eliminate excess heat from the PV cells and the lack of actual system operational performance data are perceived as obstacles to RTPV acceptance for space applications. Between 1994 and 1997 EDTEK optimized the key converter components for an RTPV generator under Department of Energy (DOE) funding administered via subcontracts to Orbital Sciences Corporation (OSC) and EG&G Mound Applied Technologies Laboratory (Horne, 1995). The optimized components included a resonant micromesh infrared bandpass filter, low-bandgap GaSb PV cells and cell arrays. Parametric data from these components were supplied to OSC who developed and analyzed the performance of 100 W, 20 W, and 10 W RTPV generators. These designs are described in references (Schock 1994, 1995 and 1996). Since the performance of each class of supply was roughly equivalent and simply scaled with size, this paper will consider the OSC 20 W design as a baseline. The baseline 20-W RTPV design was developed by Schock, et al of OSC and has been presented elsewhere. The

  18. Cyclotron Production of Medical Radioisotopes

    SciTech Connect

    Avila-Rodriguez, M. A.; Zarate-Morales, A.; Flores-Moreno, A.

    2010-08-04

    The cyclotron production of radioisotopes for medical applications is gaining increased significance in diagnostic molecular imaging techniques such as PET and SPECT. In this regard, radioisotope production has never been easier or more convenient until de introduction of compact medical cyclotrons in the last few decades, which allowed the use of short-lived radioisotopes in in vivo nuclear medicine studies on a routine basis. This review outlines some general considerations about the production of radioisotopes using charged particle accelerators.

  19. Radioisotopic heat source

    DOEpatents

    Jones, G.J.; Selle, J.E.; Teaney, P.E.

    1975-09-30

    Disclosed is a radioisotopic heat source and method for a long life electrical generator. The source includes plutonium dioxide shards and yttrium or hafnium in a container of tantalum-tungsten-hafnium alloy, all being in a nickel alloy outer container, and subjected to heat treatment of from about 1570$sup 0$F to about 1720$sup 0$F for about one h. (auth)

  20. Understanding Stirling engines. Technical paper

    SciTech Connect

    Beale, W.

    1984-01-01

    The paper describes the basic Stirling engine, as well as some of the most promising modern varieties. The intent is to familiarize people in developing countries with the engine's operation and range of applications.

  1. MEMS Stirling Cooler Development Update

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Wesolek, Danielle

    2003-01-01

    This presentation provides an update on the effort to build and test a prototype unit of the patented MEMS Stirling cooler concept. A micro-scale regenerator has been fabricated by Polar Thermal Technologies and is currently being integrated into a Stirling cycle simulator at Johns Hopkins University Applied Physics Laboratory. A discussion of the analysis, design, assembly, and test plans for the prototype will be presented.

  2. Ceramic Automotive Stirling Engine Program

    SciTech Connect

    Not Available

    1986-08-01

    The Ceramic Automotive Stirling Engine Program evaluated the application of advanced ceramic materials to an automotive Stirling engine. The objective of the program was to evaluate the technical feasibility of utilizing advanced ceramics to increase peak engine operating temperature, and to evaluate the performance benefits of such an increase. Manufacturing cost estimates were also developed for various ceramic engine components and compared with conventional metallic engine component costs.

  3. Ceramic automotive Stirling engine program

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The Ceramic Automotive Stirling Engine Program evaluated the application of advanced ceramic materials to an automotive Stirling engine. The objective of the program was to evaluate the technical feasibility of utilizing advanced ceramics to increase peak engine operating temperature, and to evaluate the performance benefits of such an increase. Manufacturing cost estimates were also developed for various ceramic engine components and compared with conventional metallic engine component costs.

  4. Planetary Protection Concerns During Pre-Launch Radioisotope Power System Final Integration Activities

    NASA Technical Reports Server (NTRS)

    Chen, Fei; McKay, Terri; Spry, James A.; Colozza, Anthony J.; DiStefano, Salvador

    2012-01-01

    The Advanced Stirling Radioisotope Generator (ASRG) is a next-generation radioisotope-based power system that is currently being developed as an alternative to the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). Power sources such as these may be needed for proposed missions to solar system planets and bodies that have challenging Planetary Protection (PP) requirements (e.g. Mars, Europa, Enceladus) that may support NASA s search for life, remnants of past life, and the precursors of life. One concern is that the heat from the ASRG could potentially create a region in which liquid water may occur. As advised by the NASA Planetary Protection Officer, when deploying an ASRG to Mars, the current COSPAR/NASA PP policy should be followed for Category IVc mission. Thus, sterilization processing of the ASRG to achieve bioburden reduction would be essential to meet the Planetary Protection requirements. Due to thermal constraints and associated low temperature limits of elements of the ASRG, vapor hydrogen peroxide (VHP) was suggested as a candidate alternative sterilization process to complement dry heat microbial reduction (DHMR) for the assembled ASRG. The following proposed sterilization plan for the ASRG anticipates a mission Category IVc level of cleanliness. This plan provides a scenario in which VHP is used as the final sterilization process. Keywords: Advanced Stirling Radioisotope Generator (ASRG), Planetary Protection (PP), Vapor hydrogen peroxide (VHP) sterilization.

  5. Development of Advanced Radioisotope Power Systems for NASA's Future Science Missions

    NASA Astrophysics Data System (ADS)

    Misra, A. K.

    2005-12-01

    This presentation will provide an overview of NASA's current efforts on development of advanced radioisotope power systems (RPS) for future science missions. The current efforts include development of flight qualified Multimission Radioisotope Thermoelectric Generator (MMRTG) and Stirling Radioisotope Generator (SRG) systems with nominal 100 watts power level and capability to operate in both deep space and planetary environments. In addition, advanced technology development efforts are being conducted to increase the specific power of both RTG and SRG systems to enable future science missions. The efforts also include new technologies that have the potential to provide significant increases in specific power of RPS system. A notional RPS technology development roadmap will be presented and various potential mission opportunities identified.

  6. Stirling material technology

    NASA Technical Reports Server (NTRS)

    Titran, R. H.; Stephens, J. R.; Scheuermann, C. M.

    1984-01-01

    The Stirling engine is an external combustion engine that offers the advantage of high fuel economy, low emissions, low noise, and low vibrations compared to current internal combustion automotive engines. The most critical component from a materials viewpoint is the heater head consisting of the cylinders, heating tubes, and regenerator housing. Materials requirements for the heater head include compatibility with hydrogen, resistance to hydrogen permeation, high temperature oxidation/corrosion resistance, and high temperature creep-rupture and fatigue properties. A materials research and technology program identified the wrought alloys CG-27 and 12RN72 and the cast alloys XF-818, NASAUT 4G-A1, and NASACC-1 as candidate replacements for the cobalt containing alloys used in current prototype engines. It is concluded that manufacture of the engine is feasible from low cost iron-base alloys rather than the cobalt alloys used in prototype engines. Results of research that lead to this conclusion are presented.

  7. NASA's Radioisotope Power Systems Planning and Potential Future Systems Overview

    NASA Technical Reports Server (NTRS)

    Zakrajsek, June F.; Woerner, Dave F.; Cairns-Gallimore, Dirk; Johnson, Stephen G.; Qualls, Louis

    2016-01-01

    The goal of NASA's 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), assesses the readiness of promising technologies to infuse in future generators, assesses the sustainment of key RPS capabilities and knowledge, forecasts and tracks the Program's budgetary needs, and disseminates current information about RPS to the community of potential users. This process has been refined and used to determine the current content of the RPS Program's portfolio. This portfolio currently includes an effort to mature advanced thermoelectric technology for possible integration into an enhanced Multi-Mission Radioisotope Generator (eMMRTG), sustainment and production of the currently deployed MMRTG, and technology investments that could lead to a future Stirling Radioisotope Generator (SRG). This paper describes the program planning processes that have been used, the currently available MMRTG, and one of the potential future systems, the eMMRTG.

  8. Radioisotope Power: A Key Technology for Deep Space Explorations

    NASA Technical Reports Server (NTRS)

    Schmidt, George R.; Sutliff, Thomas J.; Duddzinski, Leonard

    2009-01-01

    A Radioisotope Power System (RPS) generates power by converting the heat released from the nuclear decay of radioactive isotopes, such as Plutonium-238 (Pu-238), into electricity. First used in space by the U.S. in 1961, these devices have enabled some of the most challenging and exciting space missions in history, including the Pioneer and Voyager probes to the outer solar system; the Apollo lunar surface experiments; the Viking landers; the Ulysses polar orbital mission about the Sun; the Galileo mission to Jupiter; the Cassini mission orbiting Saturn; and the recently launched New Horizons mission to Pluto. Radioisotopes have also served as a versatile heat source for moderating equipment thermal environments on these and many other missions, including the Mars exploration rovers, Spirit and Opportunity. The key advantage of RPS is its ability to operate continuously, independent of orientation and distance relative to the Sun. Radioisotope systems are long-lived, rugged, compact, highly reliable, and relatively insensitive to radiation and other environmental effects. As such, they are ideally suited for missions involving long-lived, autonomous operations in the extreme conditions of space and other planetary bodies. This paper reviews the history of RPS for the U.S. space program. It also describes current development of a new Stirling cycle-based generator that will greatly expand the application of nuclear-powered missions in the future.

  9. Radioisotope Power: A Key Technology for Deep Space Exploration

    NASA Technical Reports Server (NTRS)

    Schmidt, George; Sutliff, Tom; Dudzinski, Leonard

    2008-01-01

    A Radioisotope Power System (RPS) generates power by converting the heat released from the nuclear decay of radioactive isotopes, such as Plutonium-238 (Pu-238), into electricity. First used in space by the U.S. in 1961, these devices have enabled some of the most challenging and exciting space missions in history, including the Pioneer and Voyager probes to the outer solar system; the Apollo lunar surface experiments; the Viking landers; the Ulysses polar orbital mission about the Sun; the Galileo mission to Jupiter; the Cassini mission orbiting Saturn; and the recently launched New Horizons mission to Pluto. Radioisotopes have also served as a versatile heat source for moderating equipment thermal environments on these and many other missions, including the Mars exploration rovers, Spirit and Opportunity. The key advantage of RPS is its ability to operate continuously, independent of orientation and distance relative to the Sun. Radioisotope systems are long-lived, rugged, compact, highly reliable, and relatively insensitive to radiation and other environmental effects. As such, they are ideally suited for missions involving long-lived, autonomous operations in the extreme conditions of space and other planetary bodies. This paper reviews the history of RPS for the U.S. space program. It also describes current development of a new Stirling cycle-based generator that will greatly expand the application of nuclear-powered missions in the future.

  10. Radioisotope Electric Propulsion Centaur Orbiter Spacecraft Design Overview

    NASA Technical Reports Server (NTRS)

    Oleson, Steve; McGuire, Melissa; Sarver-Verhey, Tim; Juergens, Jeff; Parkey, Tom; Dankanich, John; Fiehler, Doug; Gyekenyesi, John; Hemminger, Joseph; Gilland, Jim; Colozza, Tony; Packard, Tom; Nguyen, Thahn; Schmitz, Paul; Ostdiek, Paul; Gold, Rob; Lisse, Carey; Hibbits, Karl

    2009-01-01

    Radioisotope electric propulsion (REP) has been shown in past studies to enable missions to outerplanetary bodies including the orbiting of Centaur asteroids. Key to the feasibility for REP missions are long life, low power electric propulsion (EP) devices, low mass radioisotope power systems (RPS) and light spacecraft (S/C) components. In order to determine what are the key parameters for EP devices to perform these REP missions a design study was completed to design an REP S/C to orbit a Centaur in a New Frontiers cost cap. The design shows that an orbiter using several long lived (approximately 200 kg Xenon throughput), low power (approximately 700 W) Hall thrusters teamed with six (150 W each) Advanced Stirling Radioisotope Generators (ASRG) can deliver 60 kg of science instruments to a Centaur in 10 yr within the New Frontiers cost cap. Optimal specific impulses for the Hall thrusters were found to be around 2000 sec with thruster efficiencies over 40%. Not only can the REP S/C enable orbiting a Centaur (when compared to an all chemical mission only capable of flybys) but the additional power from the REP system can be reused to enhance science and simplify communications.

  11. Taming Highly Charged Radioisotopes

    NASA Astrophysics Data System (ADS)

    Chowdhury, Usman; Eberhardt, Benjamin; Jang, Fuluni; Schultz, Brad; Simon, Vanessa; Delheij, Paul; Dilling, Jens; Gwinner, Gerald

    2012-10-01

    The precise and accurate mass of short-lived radioisotopes is a very important parameter in physics. Contribution to the improvement of nuclear models, metrological standard fixing and tests of the unitarity of the Caibbibo-Kobayashi-Maskawa (CKM) matrix are a few examples where the mass value plays a major role. TRIUMF's ion trap for atomic and nuclear physics (TITAN) is a unique facility of three online ion traps that enables the mass measurement of short-lived isotopes with high precision (˜10-8). At present TITAN's electron beam ion trap (EBIT) increases the charge state to increase the precision, but there is no facility to significantly reduce the energy spread introduced by the charge breeding process. The precision of the measured mass of radioisotopes is linearly dependent on the charge state while the energy spread of the charged radioisotopes affects the precision adversely. To boost the precision level of mass measurement at TITAN without loosing too many ions, a cooler Penning trap (CPET) is being developed. CPET is designed to use either positively (proton) or negatively (electron) charged particles to reduce the energy spread via sympathetic cooling. Off-line setup of CPET is complete. Details of the working principles and updates are presented

  12. Lateral Load Testing of the Advanced Stirling Convertor (ASC-E2) Heater Head

    NASA Technical Reports Server (NTRS)

    Cornell, Peggy A.; Krause, David L.; Davis, Glen; Robbie, Malcolm G.; Gubics, David A.

    2010-01-01

    Free-piston Stirling convertors are fundamental to the development of NASA s next generation of radioisotope power system, the Advanced Stirling Radioisotope Generator (ASRG). The ASRG will use General Purpose Heat Source (GPHS) modules as the energy source and Advanced Stirling Convertors (ASCs) to convert heat into electrical energy, and is being developed by Lockheed Martin under contract to the Department of Energy. Achieving flight status mandates that the ASCs satisfy design as well as flight requirements to ensure reliable operation during launch. To meet these launch requirements, GRC performed a series of quasi-static mechanical tests simulating the pressure, thermal, and external loading conditions that will be experienced by an ASC E2 heater head assembly. These mechanical tests were collectively referred to as lateral load tests since a primary external load lateral to the heater head longitudinal axis was applied in combination with the other loading conditions. The heater head was subjected to the operational pressure, axial mounting force, thermal conditions, and axial and lateral launch vehicle acceleration loadings. To permit reliable prediction of the heater head s structural performance, GRC completed Finite Element Analysis (FEA) computer modeling for the stress, strain, and deformation that will result during launch. The heater head lateral load test directly supported evaluation of the analysis and validation of the design to meet launch requirements. This paper provides an overview of each element within the test and presents assessment of the modeling as well as experimental results of this task.

  13. Lateral Load Testing of the Advanced Stirling Convertor (ASC-E2) Heater Head

    NASA Technical Reports Server (NTRS)

    Cornell, Peggy A.; Krause, David L.; Davis, Glen; Robbie, Malcolm G.; Gubics, David A.

    2010-01-01

    Free-piston Stirling convertors are fundamental to the development of NASA s next generation of radioisotope power system, the Advanced Stirling Radioisotope Generator (ASRG). The ASRG will use General Purpose Heat Source (GPHS) modules as the energy source and Advanced Stirling Convertors (ASCs) to convert heat into electrical energy, and is being developed by Lockheed Martin under contract to the Department of Energy. Achieving flight status mandates that the ASCs satisfy design as well as flight requirements to ensure reliable operation during launch. To meet these launch requirements, GRC performed a series of quasi-static mechanical tests simulating the pressure, thermal, and external loading conditions that will be experienced by an ASC-E2 heater head assembly. These mechanical tests were collectively referred to as "lateral load tests" since a primary external load lateral to the heater head longitudinal axis was applied in combination with the other loading conditions. The heater head was subjected to the operational pressure, axial mounting force, thermal conditions, and axial and lateral launch vehicle acceleration loadings. To permit reliable prediction of the heater head s structural performance, GRC completed Finite Element Analysis (FEA) computer modeling for the stress, strain, and deformation that will result during launch. The heater head lateral load test directly supported evaluation of the analysis and validation of the design to meet launch requirements. This paper provides an overview of each element within the test and presents assessment of the modeling as well as experimental results of this task.

  14. Lateral Load Testing of the Advanced Stirling Convertor (ASC-E2) Heater Head

    NASA Technical Reports Server (NTRS)

    Cornell, Peggy A.; Krause, David L.; Davis, Glen; Robbie, Malcolm G.; Gubics, David A.

    2011-01-01

    Free-piston Stirling convertors are fundamental to the development of NASA s next generation of radioisotope power system, the Advanced Stirling Radioisotope Generator (ASRG). The ASRG will use General Purpose Heat Source (GPHS) modules as the energy source and Advanced Stirling Convertors (ASCs) to convert heat into electrical energy, and is being developed by Lockheed Martin under contract to the Department of Energy. Achieving flight status mandates that the ASCs satisfy design as well as flight requirements to ensure reliable operation during launch. To meet these launch requirements, GRC performed a series of quasi-static mechanical tests simulating the pressure, thermal, and external loading conditions that will be experienced by an ASC-E2 heater head assembly. These mechanical tests were collectively referred to as "lateral load tests" since a primary external load lateral to the heater head longitudinal axis was applied in combination with the other loading conditions. The heater head was subjected to the operational pressure, axial mounting force, thermal conditions, and axial and lateral launch vehicle acceleration loadings. To permit reliable prediction of the heater head s structural performance, GRC completed Finite Element Analysis (FEA) computer modeling for the stress, strain, and deformation that will result during launch. The heater head lateral load test directly supported evaluation of the analysis and validation of the design to meet launch requirements. This paper provides an overview of each element within the test and presents assessment of the modeling as well as experimental results of this task.

  15. The Stirling alternative. Power systems, refrigerants and heat pumps

    SciTech Connect

    Walker, G.; Reader, G.; Fauvel, O.R.; Bingham, E.R. )

    1993-01-01

    This book provides an up-to-date reference on the technology, history, and practical applications of Stirling engines, including recent developments in the field and a convenient survey of the Stirling engine literature. The topics of the book include: fundamentals of Stirling technology, definition and terminology, thermodynamic laws and cycles: some elementary considerations, the Stirling cycle, practical regenerative cycle, theoretical aspects and computer simulation of Stirling machines, mechanical arrangements, control systems, heat exchangers, performance characteristics, working fluids, applications of Stirling machines, advantages of Stirling machines, disadvantages of Stirling machines, Stirling versus internal combustion engines, Stirling versus Rankine engines, applications for Stirling machines, Stirling power systems, the literature and sources of supply, the literature of Stirling engines, and the literature of cryocoolers.

  16. Stirling Energy Systems` (SES) dish-Stirling program

    SciTech Connect

    Stone, K.W.; Braun, H.W.; Moore, M.I.; Clark, T.B.

    1997-12-31

    This paper describes a system to produce electrical power from the sun, and the plans for preparing it for commercial operation. The point-focus, Stirling-engine-based system was designed and tested in the 1980s by McDonnell Douglas Corporation and United Stirling AB of Sweden (now part of Kockums AB). Stirling Energy Systems (SES) has acquired the existing hardware and technology, and plans to upgrade the system in order to utilize its demonstrated performance to produce grid-compatible electrical power. The performance includes a higher solar-to-electric conversion efficiency than any other renewable energy technology (approximately 30%), with the potential of a two to four point increase. The paper presents a summary description of the hardware, its past test program, proposed improvements, and the plan for commercialization.

  17. The stirling engine for vehicle propulsion

    NASA Technical Reports Server (NTRS)

    Kuhlman, P.

    1978-01-01

    The performance data of experimental Stirling engines are considered along with questions of exhaust-gas composition, engine noise, engine volume and weight, engine control, and the engine-starting process. The Stirling engine can use practically any liquid or gaseous fuel for its operation. It is found that technically a use of the Stirling engine in motor vehicles is feasible. Economic questions related to an introduction of the Stirling engine are discussed along with possible new developments which could improve the economic situation in favor of a use of Stirling engine.

  18. Innovation at Stirling

    NASA Astrophysics Data System (ADS)

    1998-11-01

    The 24th Stirling Meeting of the Scottish Branch of the Institute of Physics was held on 21 May 1998. It was, for the first time, coupled to a Physics Update Course, which then continued in the Heriot-Watt University over the following two days. This encouraged many more exhibitors to come to Stirling where some 220 physics teachers were present. Ten manufacturers, five publishers and, of course, the ASE and the Institute of Physics exhibited materials during the conference. Morning In his introductory remarks Jack Woolsey reminded teachers that a great deal of information about the Scottish Qualifications Authority was available on the web (http://www.sqa.org.uk). Lorna Neill chaired the morning session, which was devoted to teaching chips and assessing pupils! Tony Joyce (Motorola) emphasized the need to invest in the skills required by the electronics industry. There has been an explosion in the demand for microchips and Motorola, together with Edinburgh University, Compugraphics and Scottish Enterprise, have produced a number of `teaching chips' which are being used throughout Britain and abroad. Les Haworth (Edinburgh University) discussed the construction, operating principles and educational relevance of MOS devices. MOSFETs, he claimed, are the best vehicle for early teaching of device physics. Andrew Moore (Balerno High School) gave an entertaining presentation in which he suggested ways of using the `teaching chips' in practice. Although there were many good information sheets with suggested experiments and investigations, teachers often found it difficult to tailor them to specific courses. To reduce hassle Andrew recommended using the Teaching Chip Project Board which was now available. It was particularly useful for practical investigations at Standard Grade. For the question session Jim Jamieson (SSERC) and Walter Whitelaw (Edinburgh Council) joined the three speakers. Ian Kennedy (Kilwinning Academy) described a fascinating system, developed in his

  19. Experimental and Computational Analysis of Unidirectional Flow Through Stirling Engine Heater Head

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.; Dyson, Rodger W.; Tew, Roy C.; Demko, Rikako

    2006-01-01

    A high efficiency Stirling Radioisotope Generator (SRG) is being developed for possible use in long-duration space science missions. NASA s advanced technology goals for next generation Stirling convertors include increasing the Carnot efficiency and percent of Carnot efficiency. To help achieve these goals, a multi-dimensional Computational Fluid Dynamics (CFD) code is being developed to numerically model unsteady fluid flow and heat transfer phenomena of the oscillating working gas inside Stirling convertors. In the absence of transient pressure drop data for the zero mean oscillating multi-dimensional flows present in the Technology Demonstration Convertors on test at NASA Glenn Research Center, unidirectional flow pressure drop test data is used to compare against 2D and 3D computational solutions. This study focuses on tracking pressure drop and mass flow rate data for unidirectional flow though a Stirling heater head using a commercial CFD code (CFD-ACE). The commercial CFD code uses a porous-media model which is dependent on permeability and the inertial coefficient present in the linear and nonlinear terms of the Darcy-Forchheimer equation. Permeability and inertial coefficient were calculated from unidirectional flow test data. CFD simulations of the unidirectional flow test were validated using the porous-media model input parameters which increased simulation accuracy by 14 percent on average.

  20. Test Rack Development for Extended Operation of Advanced Stirling Convertors at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Dugala, Gina M.

    2010-01-01

    The U.S. Department of Energy, Lockheed Martin Space Systems Company, Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for use as a power system on space science missions. This generator will make use of free-piston Stirling convertors to achieve higher conversion efficiency than with currently available alternatives. One part of NASA GRC's support of ASRG development includes extended operation testing of Advanced Stirling Convertors (ASCs) developed by Sunpower Inc. and GRC. The ASC consists of a free-piston Stirling engine integrated with a linear alternator. NASA GRC has been building test facilities to support extended operation of the ASCs for several years. Operation of the convertors in the test facility provides convertor performance data over an extended period of time. One part of the test facility is the test rack, which provides a means for data collection, convertor control, and safe operation. Over the years, the test rack requirements have changed. The initial ASC test rack utilized an alternating-current (AC) bus for convertor control; the ASRG Engineering Unit (EU) test rack can operate with AC bus control or with an ASC Control Unit (ACU). A new test rack is being developed to support extended operation of the ASC-E2s with higher standards of documentation, component selection, and assembly practices. This paper discusses the differences among the ASC, ASRG EU, and ASC-E2 test racks.

  1. Dish Stirling solar receiver program

    NASA Technical Reports Server (NTRS)

    Haglund, R. A.

    1980-01-01

    A technology demonstration of a Dish Stirling solar thermal electric system can be accomplished earlier and at a much lower cost than previous planning had indicated by employing technical solutions that allow already existing hardware, with minimum modifications, to be integrated into a total system with a minimum of development. The DSSR operates with a modified United Stirling p-40 engine/alternator and the JPL Test Bed Concentrator as a completely integrated solar thermal electric system having a design output of 25 kWe. The system is augmented by fossil fuel combustion which ensures a continuous electrical output under all environmental conditions. Technical and economic studies by government and industry in the United States and abroad identify the Dish Stirling solar electric system as the most appropriate, efficient and economical method for conversion of solar energy to electricity in applications when the electrical demand is 10 MWe and less.

  2. Novel diaphragm based Stirling cryocooler

    NASA Astrophysics Data System (ADS)

    Caughley, Alan; Tucker, Alan; Gschwendtner, Michael; Sellier, Mathieu

    2012-06-01

    Industrial Research Ltd has developed a unique diaphragm-based pressure wave generator technology for employment in pulse tube and Stirling cryocoolers. The system uses a pair of metal diaphragms to separate the clean cryocooler gas circuit from a conventionally lubricated mechanical driver, thus producing a clean pressure wave with a long-life drive. We have now extended the same diaphragm concept to support and seal the displacer in a free piston Stirling expander. The diaphragms allow displacer movement without rubbing or clearance gap seals, hence allowing for the development of costeffective long-life and efficient Stirling cryocoolers. Initial modeling, operating in conjunction with a 200 cc swept volume pressure wave generator, predicted in excess of 300 W cooling at 77 K with a Carnot efficiency of over 25%. A proof-of-concept prototype has achieved cryogenic temperatures. Details of the concept, modeling, and testing will be presented.

  3. High performance solar Stirling system

    NASA Technical Reports Server (NTRS)

    Stearns, J. W.; Haglund, R.

    1981-01-01

    A full-scale Dish-Stirling system experiment, at a power level of 25 kWe, has been tested during 1981 on the Test Bed Concentrator No. 2 at the Parabolic Dish Test Site, Edwards, CA. Test components, designed and developed primarily by industrial contractors for the Department of Energy, include an advanced Stirling engine driving an induction alternator, a directly-coupled solar receiver with a natural gas combustor for hybrid operation and a breadboard control system based on a programmable controller and standard utility substation components. The experiment demonstrated practicality of the solar Stirling application and high system performance into a utility grid. This paper describes the design and its functions, and the test results obtained.

  4. Automotive Stirling engine development program

    NASA Technical Reports Server (NTRS)

    Ernst, W.; Richey, A.; Farrell, R.; Riecke, G.; Smith, G.; Howarth, R.; Cronin, M.; Simetkosky, M.; Meacher, J.

    1986-01-01

    This is the ninth Semiannual Technical Progress Report prepared under the Automotive Stirling Engine Development Program. It covers the twenty-eighth and twenty-ninth quarters of activity after award of the contract. Quarterly Technical Progress Reports related program activities from the first through the thirteenth quarters; thereafter, reporting was changed to a Semiannual format. This report summarizes the study of higher-power kinematic Stirling engines for transportation use, development testing of Mod I Stirling engines, and component development activities. Component development testing included successful conical fuel nozzle testing and functional checkout of Mod II controls and auxiliaries on Mod I engine test beds. Overall program philosophy is outlined and data and test results are presented.

  5. Stirling Microregenerators Fabricated and Tested

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.

    2004-01-01

    A mesoscale Stirling refrigerator patented by the NASA Glenn Research Center is currently under development. This refrigerator has a predicted efficiency of 30 percent of Carnot and potential uses in electronics, sensors, optical and radiofrequency systems, microarrays, and microsystems. The mesoscale Stirling refrigerator is most suited to volume-limited applications that require cooling below the ambient or sink temperature. Primary components of the planar device include two diaphragm actuators that replace the pistons found in traditional-scale Stirling machines and a microregenerator that stores and releases thermal energy to the working gas during the Stirling cycle. Diaphragms are used to eliminate frictional losses and bypass leakage concerns associated with pistons, while permitting reversal of the hot and cold sides of the device during operation to allow precise temperature control. Three candidate microregenerators were fabricated under NASA grants for initial evaluation: two constructed of porous ceramic, which were fabricated by Johns Hopkins Applied Physics Laboratory, and one made of multiple layers of nickel and photoresist, which was fabricated by Polar Thermal Technologies. The candidate regenerators are being tested by Johns Hopkins Applied Physics in a custom piezoelectric-actuated test apparatus designed to produce the Stirling refrigeration cycle. In parallel with the regenerator testing, Johns Hopkins is using deep reactive ion etching to fabricate electrostatically driven, comb-drive diaphragm actuators. These actuators will drive the Stirling cycle in the prototype device. The top photograph shows the porous ceramic microregenerators. Two microregenerators were fabricated with coarse pores and two with fine pores. The bottom photograph shows the test apparatus parts for evaluating the microregenerators, including the layered nickel-and-photoresist regenerator fabricated using LIGA techniques.

  6. Third generation development of an 11-watt Stirling converter

    SciTech Connect

    Montgomery, W.L.; Ross, B.A.; Penswick, L.B.

    1996-12-31

    This paper describes recent design enhancements, performance results, and development of an artificial neural network (ANN) model related to the Radioisotope Stirling Generator (RSG), an 11-watt converter designed for remote power applications. Design enhancements include minor changes to improve performance, increase reliability, facilitate fabrication and assembly for limited production, and reduce mass. Innovative modifications were effected to increase performance and improve reliability of the vacuum foil insulation (VFI) package and linear alternator. High and low operating temperature acceptance testing of the Engineering Model (EM) demonstrated the robust system characteristics. These tests were conducted for 1 week of operation each, with rejector temperatures of 95 C and 20 C, respectively. Endurance testing continues for a complete Stirling converter, the Development Model (DM), with over 25,000 hours of maintenance-free operation. Endurance testing of flexures has attained over 540 flexure-years and endurance testing of linear motors/alternators has achieved nearly 27,000 hours of operation without failure. An ANN model was developed and tested successfully on the DM. Rejection temperatures were varied between 3 C and 75 C while load voltages ranged between engine stall and displacer overstroke. The trained ANN model, based solely on externally measured parameters, predicted values of piston amplitude, displacer amplitude, and piston-displacer phase angle within {+-}2% of the measured values over the entire operating regime. The ANN model demonstrated its effectiveness in the long-term evaluation of free-piston Stirling machines without adding the complexity, reduced reliability, and increased cost of sophisticated diagnostic instrumentation.

  7. Advanced Stirling Convertor Durability Testing: Plans and Interim Results

    NASA Technical Reports Server (NTRS)

    Meer, David W.; Oriti, Salvatore M.

    2012-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Corporation (LM), and NASA Glenn Research Center (GRC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. In support of this program, GRC has been involved in testing Stirling convertors, including the Advanced Stirling Convertor (ASC), for use in the ASRG. This testing includes electromagnetic interference/compatibility (EMI/EMC), structural dynamics, advanced materials, organics, and unattended extended operation. The purpose of the durability tests is to experimentally demonstrate the margins in the ASC design. Due to the high value of the hardware, previous ASC tests focused on establishing baseline performance of the convertors within the nominal operating conditions. The durability tests present the first planned extension of the operating conditions into regions beyond those intended to meet the product spec, where the possibility exists of lateral contact, overstroke, or over-temperature events. These tests are not intended to cause damage that would shorten the life of the convertors, so they can transition into extended operation at the conclusion of the tests. This paper describes the four tests included in the durability test sequence: 1) start/stop cycling, 2) exposure to constant acceleration in the lateral and axial directions, 3) random vibration at increased piston amplitude to induce contact events, and 4) overstroke testing to simulate potential failures during processing or during the mission life where contact events could occur. The paper also summarizes the analysis and simulation used to predict the results of each of these tests.

  8. Advanced Stirling Convertor Durability Testing: Plans and Interim Results

    NASA Technical Reports Server (NTRS)

    Meer, Dave; Oriti, Sal

    2012-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Corporation (LM), and NASA Glenn Research Center (GRC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. In support of this program, NASA?s Glenn Research Center (GRC) has been involved in testing Stirling convertors, including the Advanced Stirling Convertor (ASC), for use in the ASRG. This testing includes electromagnetic interference/compatibility (EMI/EMC), structural dynamics, advanced materials, organics, and unattended extended operation. The purpose of the durability tests is to experimentally demonstrate the margins in the ASC design. Due to the high value of the hardware, previous ASC tests focused on establishing baseline performance of the convertors within the nominal operating conditions. The durability tests present the first planned extension of the operating conditions into regions beyond those intended to meet the product spec, where the possibility exists of lateral contact, overstroke, or over-temperature events. These tests are not intended to cause damage that would shorten the life of the convertors, so they can transition into extended operation at the conclusion of the tests. This paper describes the four tests included in the durability test sequence: 1) start/stop cycling, 2) exposure to constant acceleration in the lateral and axial directions, 3) random vibration at increased piston amplitude to induce contact events, and 4) overstroke testing to simulate potential failures during processing or during the mission life where contact events could occur. The paper also summarizes the analysis and simulation used to predict the results of each of these tests.

  9. Permeability of Candidate Stirling Heater Head Materials Measured

    NASA Technical Reports Server (NTRS)

    Freedman, Marc R.; Singh, Mrityunjay

    2005-01-01

    Researchers at the NASA Glenn Research Center are evaluating high-temperature materials for Stirling heater heads for second- and third-generation Stirling radioisotope power systems that would help to increase the system efficiency to 30 to 35 percent and the system specific power to 8 to 10+ W/kg. Ceramic materials could make it possible for the convertor hot-end temperature to be increased to 1050 to 1200 C, in comparison to the current 650 C with an Inconel 718 heater head. A hermetically sealed Stirling heater head must retain a constant internal pressure of nearly 400-psi helium (He) throughout its useful life (120,000 hr) at the design operating temperature. Therefore, He permeability was measured for eight potential materials and compared with the permeability of the current heater head material, Inconel 718. The eight materials included silicon nitride (Si3N4), silicon dioxide (SiO2), both sintered and chemical vapor deposited (CVD) silicon carbide (SiC), alumina (Al2O3), two types of melt-infiltrated (MI) SiC/SiC composites, and a carbon/SiC composite (C/SiC). Glenn submitted samples of each material to Porous Materials, Inc., Ithaca, New York, for permeability analysis. At room temperature and 30-psi He, four materials--Si3N4, Al2O3, SiO2, and sintered SiC--demonstrated lower permeability than Inconel 718. The CVD SiC and all the composite materials were significantly more permeable to He than the baseline material.

  10. Evaluation of Advanced Stirling Convertor Net Heat Input Correlation Methods Using a Thermal Standard

    NASA Technical Reports Server (NTRS)

    Briggs, Maxwell H.; Schifer, Nicholas A.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two high-efficiency Advanced Stirling Convertors (ASCs), developed by Sunpower Inc. and NASA Glenn Research Center (GRC). The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot end and cold end temperatures, and specified electrical power output for a given net heat input. In an effort to improve net heat input predictions, numerous tasks have been performed which provided a more accurate value for net heat input into the ASCs, including testing validation hardware, known as the Thermal Standard, to provide a direct comparison to numerical and empirical models used to predict convertor net heat input. This validation hardware provided a comparison for scrutinizing and improving empirical correlations and numerical models of ASC-E2 net heat input. This hardware simulated the characteristics of an ASC-E2 convertor in both an operating and non-operating mode. This paper describes the Thermal Standard testing and the conclusions of the validation effort applied to the empirical correlation methods used by the Radioisotope Power System (RPS) team at NASA Glenn.

  11. Performance Measurement of Advanced Stirling Convertors (ASC-E3)

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.

    2013-01-01

    NASA Glenn Research Center (GRC) has been supporting development of the Advanced Stirling Radioisotope Generator (ASRG) since 2006. A key element of the ASRG project is providing life, reliability, and performance testing data of the Advanced Stirling Convertor (ASC). The latest version of the ASC (ASC-E3, to represent the third cycle of engineering model test hardware) is of a design identical to the forthcoming flight convertors. For this generation of hardware, a joint Sunpower and GRC effort was initiated to improve and standardize the test support hardware. After this effort was completed, the first pair of ASC-E3 units was produced by Sunpower and then delivered to GRC in December 2012. GRC has begun operation of these units. This process included performance verification, which examined the data from various tests to validate the convertor performance to the product specification. Other tests included detailed performance mapping that encompassed the wide range of operating conditions that will exist during a mission. These convertors were then transferred to Lockheed Martin for controller checkout testing. The results of this latest convertor performance verification activity are summarized here.

  12. Advanced Stirling Convertor Dynamic Test Approach and Results

    NASA Technical Reports Server (NTRS)

    Meer, David W.; Hill, Dennis; Ursic, Joseph

    2009-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin (LM), and NASA Glenn Research Center (GRC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. As part of the extended operation testing of this power system, the Advanced Stirling Converters (ASC) at NASA John H. Glenn Research Center undergo a vibration test sequence intended to simulate the vibration history of an ASC used in an ASRG for a space mission. This sequence includes testing at Workmanship and Flight Acceptance levels interspersed with periods of extended operation to simulate pre and post fueling. The final step in the test sequence utilizes additional testing at Flight Acceptance levels to simulate launch. To better replicate the acceleration profile seen by an ASC incorporated into an ASRG, the input spectra used in testing the convertors was modified based on dynamic testing of the ASRG Engineering Unit ( ASRG-EU) at Lockheed Martin. This paper presents the vibration test plan for current and future ASC units, including the modified input spectra, and the results of recent tests using these spectra. The test results include data from several accelerometers mounted on the convertors as well as the piston position and output power variables.

  13. Advanced Stirling Convertor Dynamic Test Approach and Results

    NASA Technical Reports Server (NTRS)

    Meer, David W.; Hill, Dennis; Ursic, Joseph J.

    2010-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Corporation (LM), and NASA Glenn Research Center (GRC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. As part of the extended operation testing of this power system, the Advanced Stirling Convertors (ASC) at NASA GRC undergo a vibration test sequence intended to simulate the vibration history that an ASC would experience when used in an ASRG for a space mission. This sequence includes testing at workmanship and flight acceptance levels interspersed with periods of extended operation to simulate prefueling and post fueling. The final step in the test sequence utilizes additional testing at flight acceptance levels to simulate launch. To better replicate the acceleration profile seen by an ASC incorporated into an ASRG, the input spectra used in testing the convertors was modified based on dynamic testing of the ASRG Engineering Unit (ASRG EU) at LM. This paper outlines the overall test approach, summarizes the test results from the ASRG EU, describes the incorporation of those results into the test approach, and presents the results of applying the test approach to the ASC-1 #3 and #4 convertors. The test results include data from several accelerometers mounted on the convertors as well as the piston position and output power variables.

  14. Miniaturized stirling type cooler

    SciTech Connect

    Pundak, N.

    1988-09-13

    This patent describes a cryogenic Stirling type cooler system, an axially extending casing, a compressor unit located within the casing and including a crankshaft extending transversely of the casing axis, an expander and expander connecting rod arranged co-axially in and with the casing the casing including a cover having an axis in coaxial relation with the crankshaft, the casing and cover forming a sealed housing for the compressor unit and crankshaft. The cover consists of a cup-shaped non-magnetic partition, a drive for the compressor unit comprising a D.C. brushless motor including a stator, a rotor and driving electronics. The rotor located within the cover in the sealed housing and coupled directly to the crankshaft, the crankshaft connected to the expander and compressor connecting rods, the stator located outwardly of an encircling the cover in co-axial relation with the rotor. The drive electronics located outwardly of the casing, whereby the rotor is located within the sealed housing in driving engagement with the crankshaft while the stator is located outside the sealed housing for driving the rotor so that the rotor supplies rotational movement to the crankshaft which is converted by the crankshaft cam for driving the expander and compressor connecting rod.

  15. Long-Term Durability Analysis of a 100,000+ Hr Stirling Power Convertor Heater Head

    NASA Technical Reports Server (NTRS)

    Bartolotta, Paul A.; Bowman, Randy R.; Krause, David L.; Halford, Gary R.

    2000-01-01

    DOE and NASA have identified Stirling Radioisotope Power Systems (SRPS) as the power supply for deep space exploration missions the Europa Orbiter and Solar Probe. As a part of this effort, NASA has initiated a long-term durability project for critical hot section components of the Stirling power convertor to qualify flight hardware. This project will develop a life prediction methodology that utilizes short-term (t < 20,000 hr) test data to verify long-term (t > 100,000 hr) design life. The project consists of generating a materials database for the specific heat of alloy, evaluation of critical hermetic sealed joints, life model characterization, and model verification. This paper will describe the qualification methodology being developed and provide a status for this effort.

  16. Conceptual Trade Study of General Purpose Heat Source Powered Stirling Converter Configurations

    NASA Technical Reports Server (NTRS)

    Turpin, J. B.

    2007-01-01

    This Technical Manual describes a parametric study of general purpose heat source (GPHS) powered Stirling converter configurations. This study was performed in support of MSFC s efforts to establish the capability to perform non-nuclear system level testing and integration of radioisotope power systems. Six different GPHS stack configurations at a total of three different power levels (80, 250, and 500 W(sub e) were analyzed. The thermal profiles of the integrated GPHS modules (for each configuration) were calculated to determine maximum temperatures for comparison to allowable material limits. Temperature profiles for off-nominal power conditions were also assessed in order to better understand how power demands from the Stirling engine impact the performance of a given configuration.

  17. Free-piston Stirling Engine system considerations for various space power applications

    NASA Technical Reports Server (NTRS)

    Dochat, George R.; Dhar, Manmohan

    1991-01-01

    Free-Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSE can be coupled with many potential heat sources (radioisotope, solar, or nuclear reactor), various heat input systems (pumped loop, heat pipe), heat rejection (pumped loop or heat pipe), and various power management and distribution systems (ac, dc, high or low voltage, and fixed or variable load). This paper reviews potential space missions that can be met using free-piston Stirling engines and discusses options of various system integration approaches. This paper briefly outlines the program and recent progress.

  18. Thermal Performance Expectations of the Advanced Stirling Convertor Over a Range of Operating Scenarios

    NASA Technical Reports Server (NTRS)

    Reid, Terry V.; Dyson, Rodger W.

    2010-01-01

    The Advanced Stirling Radioisotope Generator (ASRG) will enable various missions such as small body sample return, atmospheric missions around Venus, as well as long - duration deep space missions. Analysis of the temperature distributions are performed on an Advanced Stirling Convertor, and the results are compared with available experimental measurements. This analysis includes applied environmental conditions that are similar to those that will be experienced while the convertor is in operation. The applied conditions represent a potential mission profile including pre-takeoff sterilization, launch, transit, and return. The results focus on the anticipated peak temperatures of the magnets in the linear alternator. These results confirm that the ASC can support future missions to deep space targets, extreme environment landers, as well as more conventional goals.

  19. Organic Materials Ionizing Radiation Susceptibility for the Outer Planet/Solar Probe Radioisotope Power Source

    NASA Technical Reports Server (NTRS)

    Golliher, Eric L.; Pepper, Stephen V.

    2001-01-01

    The Department of Energy is considering the current Stirling Technology Corporation 55 We Stirling Technology Demonstration Convertor as a baseline option for an advanced radioisotope power source for the Outer Planets/Solar Probe project of Jet Propulsion Laboratory and other missions. However, since the Technology Demonstration Convertor contains organic materials chosen without any special consideration of flight readiness, and without any consideration of the extremely high radiation environment of Europa, a preliminary investigation was performed to address the radiation susceptibility of the current organic materials used in the Technology Demonstration Convertor. This report documents the results of the investigation. The results of the investigation show that candidate replacement materials have been identified to be acceptable in the harsh Europa radiation environment.

  20. Stirling engines and irrigation pumping

    SciTech Connect

    West, C.D.

    1987-08-01

    This report was prepared in support of the Renewable Energy Applications and Training Project sponsored by the US Agency for International Development for which ORNL provides technical assistance. It briefly outlines the performance that might be achievable from various kinds of Stirling-engine-driven irrigation pumps. Some emphasis is placed on the very simple liquid-piston engines that have been the subject of research in recent years and are suitable for manufacture in less well-developed countries. In addition to the results quoted here (possible limits on M/sup 4/ and pumping head for different-size engines and various operating conditions), the method of calculation is described in sufficient detail for engineers to apply the techniques to other Stirling engine designs for comparison. The liquid-piston Fluidyne is a form of Stirling engine sharing many of the characteristics of conventional kinematic and free-piston Stirling machines. The use of liquid pistons, however, gives it some unique advantages as well as certain problems that are not encountered or are not important in engines with solid pistons. Because the output is naturally available in the form of an oscillating liquid flow or a fluctuating pressure, the Fluidyne is well suited to liquid pumping, but other applications have also been considered. 27 refs., 7 figs., 2 tabs.

  1. Automotive Stirling Engine Development Program

    NASA Technical Reports Server (NTRS)

    Nightingale, N.; Ernst, W.; Richey, A.; Simetkosky, M.; Antonelli, M. (Editor)

    1982-01-01

    Activities performed on Mod I engine testing and test results; the manufacture, assembly, and test of a Mod I engine in the United States; design initiation of the Mod I-A engine system; transient performance testing; Stirling reference engine manufacturing and reduced size studies; components and subsystems; and the study and test of low cost alloys are summarized.

  2. Free-Piston Stirling Engines

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.

    1989-01-01

    Engines promise cost-effective solar-power generation. Report describes two concepts for Stirling-engine systems for conversion of solar heat to electrical energy. Recognized most promising technologies for meeting U.S. Department of Energy goals for performance and cost for terrestrial electrical-energy sources.

  3. Regenerative rotary displacer Stirling engine

    SciTech Connect

    Isshiki, Naotsugu; Watanabe, Hiroichi; Raggi, L.; Isshiki, Seita; Hirata, Koichi

    1996-12-31

    A few rotary displacer Stirling engines in which the displacer has one gas pocket space at one side and rotates in a main enclosed cylinder, which is heated from one side and cooled from opposite side without any regenerator, have been studied for some time by the authors. The authors tried to improve this engine by equipping it with a regenerator, because without a regenerator, pressure oscillation and efficiency are too small. Here, several types of regenerative rotary displacer piston Stirling engines are proposed. One is the contra-rotating tandem two disc type displacer engine using axial heat conduction through side walls or by heat pipes and another is a single disc type with circulating fluid regenerator or heat pipes. Stirling engines of this new rotary displacer type are thought to attain high speed. Here, experimental results of the original rotary displacer Stirling engine without a regenerator, and one contra-rotating tandem displacer engine with side wall regenerator by axial heat conduction are reported accompanied with a discussion of the results.

  4. Stirling engine with pressurized crankcase

    SciTech Connect

    Corey, John A.

    1988-01-01

    A two piston Stirling engine wherein the pistons are coupled to a common crankshaft via bearing means, the pistons include pad means to minimize friction between the pistons and the cylinders during reciprocation of the pistons, means for pressurizing the engine crankcase, and means for cooling the crankshaft and the bearing means eliminating the need for oil in the crankcase.

  5. A recuperative superfluid stirling refrigerator

    SciTech Connect

    Brisson, J.G.; Swift, G.W.

    1993-07-01

    A superfluid Stirling refrigerator has been built with a counterflow heat exchanger serving as a recuperative regenerator. It has achieved temperatures of 296 mK with a 4% {sup 3}He-{sup 4}He mixture. Cooling power versus temperature and speed is presented for a 6.6% mixture.

  6. Stirling engines and irrigation pumping

    SciTech Connect

    West, C.D.

    1988-01-01

    A brief outline is given of the performance that might be achievable from various kinds of Stirling engine driven irrigation pumps. Some emphasis is placed on the very simple liquid piston engines, suitable for low technology manufacture, that have been the recent subject of research. 5 refs., 3 figs., 3 tabs.

  7. 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).

  8. Innovation at Stirling

    NASA Astrophysics Data System (ADS)

    1998-11-01

    The 24th Stirling Meeting of the Scottish Branch of the Institute of Physics was held on 21 May 1998. It was, for the first time, coupled to a Physics Update Course, which then continued in the Heriot-Watt University over the following two days. This encouraged many more exhibitors to come to Stirling where some 220 physics teachers were present. Ten manufacturers, five publishers and, of course, the ASE and the Institute of Physics exhibited materials during the conference. Morning In his introductory remarks Jack Woolsey reminded teachers that a great deal of information about the Scottish Qualifications Authority was available on the web (http://www.sqa.org.uk). Lorna Neill chaired the morning session, which was devoted to teaching chips and assessing pupils! Tony Joyce (Motorola) emphasized the need to invest in the skills required by the electronics industry. There has been an explosion in the demand for microchips and Motorola, together with Edinburgh University, Compugraphics and Scottish Enterprise, have produced a number of `teaching chips' which are being used throughout Britain and abroad. Les Haworth (Edinburgh University) discussed the construction, operating principles and educational relevance of MOS devices. MOSFETs, he claimed, are the best vehicle for early teaching of device physics. Andrew Moore (Balerno High School) gave an entertaining presentation in which he suggested ways of using the `teaching chips' in practice. Although there were many good information sheets with suggested experiments and investigations, teachers often found it difficult to tailor them to specific courses. To reduce hassle Andrew recommended using the Teaching Chip Project Board which was now available. It was particularly useful for practical investigations at Standard Grade. For the question session Jim Jamieson (SSERC) and Walter Whitelaw (Edinburgh Council) joined the three speakers. Ian Kennedy (Kilwinning Academy) described a fascinating system, developed in his

  9. Stirling engine design manual. Second edition

    SciTech Connect

    Martini, W.R.

    1983-01-01

    This manual is intended to serve as an introduction to Stirling cycle heat engines, as a key to the available literature on Stirling engines and to identify non-proprietary Stirling engine design methodologies. Two different fully described Stirling engines are discussed. Engine design methods are categorized as first-order, second-order, and third-order with increased order number indicating increased complexity. FORTRAN programs are listed for both an isothermal second-order design program and an adiabatic second-order design program. Third-order methods are explained and enumerated. In this second edition of the Stirling Engine Design Manual the references have been updated. A revised personal and corporate author index is given and an expanded directory lists over 80 individuals and companies active in Stirling engines.

  10. Development of the Sunpower 35 We Free-Piston Stirling Convertor

    NASA Astrophysics Data System (ADS)

    Wood, J. Gary; Lane, Neill

    2005-02-01

    This paper describes the development and performance of the Sunpower 35 We free-piston Stirling convertor. Exceptional thermodynamic performance has been achieved in a small lightweight machine. Efficiency of over 30 percent, at a temperature ratio of 2.6 has been achieved. Specific power of the convertor in final low mass hermetically-sealed form is projected to exceed 90 watts/Kg. This convertor was developed under NASA SBIR funding. Potential applications for this convertor include highly efficient and low mass radioisotope fueled space power systems, as well as terrestrial use as a fuel fired battery replacement.

  11. Silicon Carbide Radioisotope Batteries

    NASA Technical Reports Server (NTRS)

    Rybicki, George C.

    2005-01-01

    The substantial radiation resistance and large bandgap of SiC semiconductor materials makes them an attractive candidate for application in a high efficiency, long life radioisotope battery. To evaluate their potential in this application, simulated batteries were constructed using SiC diodes and the alpha particle emitter Americium Am-241 or the beta particle emitter Promethium Pm-147. The Am-241 based battery showed high initial power output and an initial conversion efficiency of approximately 16%, but the power output decayed 52% in 500 hours due to radiation damage. In contrast the Pm-147 based battery showed a similar power output level and an initial conversion efficiency of approximately 0.6%, but no degradation was observed in 500 hours. However, the Pm-147 battery required approximately 1000 times the particle fluence as the Am-242 battery to achieve a similar power output. The advantages and disadvantages of each type of battery and suggestions for future improvements will be discussed.

  12. Vibration Modal Characterization of a Stirling Convertor via Base-Shake Excitation

    NASA Technical Reports Server (NTRS)

    Suarez, Vicente J.; Goodnight, Thomas W.; Hughes, William O.; Samorezov, Sergey

    2003-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin (LM), Stirling Technology Company (STC), and NASA John H. Glenn Research Center (GRC) are currently developing a high-efficiency Stirling convertor for use in a Stirling Radioisotope Generator (SRG). NASA and DOE have identified the SRG for potential use as an advanced power system for future NASA Space Science missions, providing spacecraft onboard electric power for deep space missions and power for unmanned Mars rovers. Low-level, baseshake sine vibration tests were conducted on the Stirling Technology Demonstration Convertor (TDC), at NASA GRC's Structural Dynamics Laboratory, in February 2001, as part of the development of this Stirling technology. The purpose of these tests was to provide a better understanding of the TDC's internal dynamic response to external vibratory base excitations. The knowledge obtained can therein be used to help explain the success that the TDC enjoyed in its previous random vibration qualification tests (December 1999). This explanation focuses on the TDC s internal dynamic characteristics in the 50 to 250 Hz frequency range, which corresponds to the maximum input levels of its qualification random vibration test specification. The internal dynamic structural characteristics of the TDC have now been measured in two separate tests under different motoring and dynamic loading conditions: (1) with the convertor being electrically motored, under a vibratory base-shake excitation load, and (2) with the convertor turned off, and its alternator internals undergoing dynamic excitation via hammer impact loading. This paper addresses the test setup, procedure and results of the base-shake vibration testing conducted on the motored TDC, and will compare these results with those results obtained from the dynamic impact tests (May 2001) on the nonmotored TDC.

  13. Stirling engine with a liquid working substance

    SciTech Connect

    Swift, G.W.

    1989-06-01

    A theoretical and experimental study of a Stirling engine using a liquid (propylene) as its working substance is presented. This is the first experimental work on liquid Stirling engines (or Malone engines) since the 1920s. Liquid-Stirling technology appears advantageous to conventional freon-based Rankine-cycle technology in many applications. The theory developed here is simple, intuitive, and modular because of the nature of liquid working fluids and because the temperature spanned by liquid Stirling engines is not large. The experimental engine is extremely versatile, and can operate as either a heat pump or prime mover. Extensive measurements with it are in substantial agreement with the simple theory.

  14. Overview of a stirling engine test project

    NASA Technical Reports Server (NTRS)

    Slaby, J. G.

    1980-01-01

    Tests were conducted on three Stirling engines ranging in size from 1.33 to 53 horsepower (1 to 40 kW). The tests were directed toward developing alternative, backup component concepts to improve engine efficiency and performance or to reduce costs. Some of the activities included investigating attractive concepts and materials for cooler-regenerator units, installing a jet impingement device on a Stirling engine to determine its potential for improved engine performance, and presenting performance maps for initial characterization of Stirling engines. The experiment results of the tests are presented along with predictions of results of future tests to be conducted on the Stirling engines.

  15. Stirling machines: From potential to practicality

    SciTech Connect

    Ross, B.

    1988-06-01

    The author describes the principle of operation behind a Stirling machine. Practical Stirling machines, which can be used as heat engines, heat pumps, and refrigerators, share several characteristics, which are described in this article. The author explains the research that is being conducted on Stirling machines. The author says Stirling machines will not replace more common types of engines, but instead will be used in specific applications where the demand for such attributes as multi-fuel capability, low emissions, and long life cannot otherwise be met.

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

    NASA Technical Reports Server (NTRS)

    Anderson, David J.; Wong, Wayne A.; Tuttle, Karen L.

    2005-01-01

    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.

  17. Three-Dimensional Magnetic Analysis Technique Developed for Evaluating Stirling Convertor Linear Alternators

    NASA Technical Reports Server (NTRS)

    Geng, Steven M.

    2003-01-01

    The Department of Energy, the Stirling Technology Company (STC), and the NASA Glenn Research Center are developing Stirling convertors for Stirling radioisotope generators to provide electrical power for future NASA deep space missions. STC is developing the 55-We technology demonstration convertor (TDC) under contract to the Department of Energy. The Department of Energy recently named Lockheed Martin as the system integration contractor for the Stirling radioisotope generator development project. Lockheed Martin will develop the Stirling radioisotope generator engineering unit and has contract options to develop the qualification unit and the first flight unit. Glenn s role includes an in-house project to provide convertor, component, and materials testing and evaluation in support of the overall power system development. As a part of this work, Glenn has established an in-house Stirling research laboratory for testing, analyzing, and evaluating Stirling machines. STC has built four 55-We convertors for NASA, and these are being tested at Glenn. A cross-sectional view of the 55-We TDC is shown in the figure. Of critical importance to the successful development of the Stirling convertor for space power applications is the development of a lightweight and highly efficient linear alternator. In support, Glenn has been developing finite element analysis and finite element method tools for performing various linear alternator thermal and electromagnetic analyses and evaluating design configurations. A three-dimensional magnetostatic finite element model of STC's 55-We TDC linear alternator was developed to evaluate the demagnetization fields affecting the alternator magnets. Since the actual linear alternator hardware is symmetric to the quarter section about the axis of motion, only a quarter section of the alternator was modeled. The components modeled included the mover laminations, the neodymium-iron-boron magnets, the stator laminations, and the copper coils. The

  18. Utilizing Radioisotope Power Systems for Human Lunar Exploration

    NASA Technical Reports Server (NTRS)

    Schreiner, Timothy M.

    2005-01-01

    The Vision for Space Exploration has a goal of sending crewed missions to the lunar surface as early as 2015 and no later than 2020. The use of nuclear power sources could aid in assisting crews in exploring the surface and performing In-Situ Resource Utilization (ISRU) activities. Radioisotope Power Systems (RPS) provide constant sources of electrical power and thermal energy for space applications. RPSs were carried on six of the crewed Apollo missions to power surface science packages, five of which still remain on the lunar surface. Future RPS designs may be able to play a more active role in supporting a long-term human presence. Due to its lower thermal and radiation output, the planned Stirling Radioisotope Generator (SRG) appears particularly attractive for manned applications. The MCNPX particle transport code has been used to model the current SRG design to assess its use in proximity with astronauts operating on the surface. Concepts of mobility and ISRU infrastructure were modeled using MCNPX to analyze the impact of RPSs on crewed mobility systems. Strategies for lowering the radiation dose were studied to determine methods of shielding the crew from the RPSs.

  19. Overview of NASA Magnet and Linear Alternator Research Efforts

    NASA Technical Reports Server (NTRS)

    Geng, Steven M.; Niedra, Janis M.; Schwarze, Gene E.

    2005-01-01

    The Department of Energy, Lockheed Martin, Stirling Technology Company, and NASA Glenn Research Center are developing a high-efficiency, 110 watt Stirling Radioisotope Generator (SRG110) for NASA Space Science missions. NASA Glenn is conducting in-house research on rare earth permanent magnets and on linear alternators to assist in developing a free-piston Stirling convertor for the SRG110 and for developing advanced technology. The permanent magnet research efforts include magnet characterization, short-term magnet aging tests, and long-term magnet aging tests. Linear alternator research efforts have begun just recently at GRC with the characterization of a moving iron type linear alternator using GRC's alternator test rig. This paper reports on the progress and future plans of GRC's magnet and linear alternator research efforts.

  20. Overview of NASA Magnet and Linear Alternator Research Efforts

    NASA Astrophysics Data System (ADS)

    Geng, Steven M.; Niedra, Janis M.; Schwarze, Gene E.

    2005-02-01

    The Department of Energy, Lockheed Martin, Stirling Technology Company, and NASA Glenn Research Center are developing a high-efficiency, 110 watt Stirling Radioisotope Generator (SRG110) for NASA Space Science missions. NASA Glenn is conducting in-house research on rare earth permanent magnets and on linear alternators to assist in developing a free-piston Stirling convertor for the SRG110 and for developing advanced technology. The permanent magnet research efforts include magnet characterization, short-term magnet aging tests, and long-term magnet aging tests. Linear alternator research efforts have begun just recently at GRC with the characterization of a moving iron type linear alternator using GRC's alternator test rig. This paper reports on the progress and future plans of GRC's magnet and linear alternator research efforts.

  1. A Simple Model for Radioisotope Power System Performance in the Titan Environment

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    Like other energy conversion devices, the performance of Radioisotope Power Systems (RPSs) for spacecraft depend on the heat transfer boundary conditions. In planetary environments, the heat transfer, and thus the RPS operating conditions and performance may be different from those in free space. In particular, we develop a simple model (based on an endoreversible heat engine with a specified heat sink) for the performance of an Advanced Stirling Radioisotope Generator (ASRG) in the dense, cold atmosphere of Titan. We find the power output of an ideal RPS in the Titan environment could be considerably superior to that in space vacuum, although an internal heat leak of the present ASRG design may somewhat compromise this improvement, resulting in an output close to, or up to 15% smaller than, predicted vacuum output. Since the model suggests significant variation due to two competing effects, performance testing in representative conditions is urgently recommended.

  2. Radioisotope Thermophotovoltaic (RTPV) Generator and Its Applicability to an Illustrative Space Mission

    SciTech Connect

    Schock, A.; Mukunda, M.; Or, T.; Kumar, V.; Summers, G.

    1994-02-14

    The paper describes the results of a DOE-sponsored design study of a radioisotope thermophotovoltaic generator (RTPV), to complement similar studies of Radioisotope Thermoelectric Generators (RTGs) and Stirling Generators (RSGs) previously published by the author. Instead of conducting a generic study, it was decided to focus the design effort by directing it at a specific illustrative space mission, Pluto Fast Flyby (PFF). That mission, under study by JPL, envisages a direct eight-year flight to Pluto (the only unexplored planet in the solar system), followed by comprehensive mapping, surface composition, and atmospheric structure measurements during a brief flyby of the planet and its moon Charon, and transmission of the recorded science data to Earth during a post-encounter cruise lasting up to one year.

  3. Stirling Engines and Irrigation Pumping

    SciTech Connect

    West, C.D.

    1987-01-01

    This report was prepared in support of the Renewable Energy Applications and Training Project that is sponsored by the U.S. Agency for International Development for which ORNL provides technical assistance. It briefly outlines the performance that might be achievable from various kinds of Stirling-engine-driven irrigation pumps. Some emphasis is placed on the very simple liquid-piston engines that have been the subject of research in recent years and are suitable for manufacture in less well-developed countries. In addition to the results quoted here (possible limits on M4 and pumping head for different-size engines and various operating conditions), the method of calculation is described in sufficient detail for engineers to apply the techniques to other Stirling engine designs for comparison.

  4. How Does Stirling Engine Work?

    NASA Astrophysics Data System (ADS)

    Biwa, Tetsushi; Tashiro, Yusuke; Yazaki, Taichi

    In this paper the working mechanism of Stirling engine is studied from the standpoint of thermoacoustic framework. The work flux measurement is performed in a glass tube equipped with/without a regenerator-heat exchanger assembly. An atmospheric pressure air confined in the tube is periodically perturbed by two speakers at the same frequency (=48Hz) but out of phase. It is experimentally demonstrated that the phasing of two pistons in the Stirling engine (alpha arrangement type) plays the role in creating a steady work flux from the compression piston to the expansion piston, whereas a differentially heated regenerator in the engine operates as a power amplifier for the traveling wave propagating up the temperature gradient.

  5. Automotive Stirling engine development program

    NASA Technical Reports Server (NTRS)

    Ernst, W.; Richey, A.; Farrell, R.; Riecke, G.; Smith, G.; Howarth, R.; Cronin, M.; Simetkosky, M.; Meacher, J.

    1986-01-01

    The major accomplishments were the completion of the Basic Stirling Engine (BSE) and the Stirling Engine System (SES) designs on schedule, the approval and acceptance of those designs by NASA, and the initiation of manufacture of BSE components. The performance predictions indicate the Mod II engine design will meet or exceed the original program goals of 30% improvement in fuel economy over a conventional Internal Combustion (IC) powered vehicle, while providing acceptable emissions. This was accomplished while simultaneously reducing Mod II engine weight to a level comparable with IC engine power density, and packaging the Mod II in a 1985 Celebrity with no external sheet metal changes. The projected mileage of the Mod II Celebrity for the combined urban and highway CVS cycle is 40.9 mpg which is a 32% improvement over the IC Celebrity. If additional potential improvements are verified and incorporated in the Mod II, the mileage could increase to 42.7 mpg.

  6. Ceramic automotive Stirling engine study

    NASA Technical Reports Server (NTRS)

    Musikant, S.; Chiu, W.; Darooka, D.; Mullings, D. M.; Johnson, C. A.

    1985-01-01

    A conceptual design study for a Ceramic Automotive Stirling Engine (CASE) is performed. Year 1990 structural ceramic technology is assumed. Structural and performance analyses of the conceptual design are performed as well as a manufacturing and cost analysis. The general conclusions from this study are that such an engine would be 10-26% more efficient over its performance map than the current metal Automotive Stirling Reference Engine (ASRE). Cost of such a ceramic engine is likely to be somewhat higher than that of the ASRE but engine cost is very sensitive to the ultimate cost of the high purity, ceramic powder raw materials required to fabricate high performance parts. When the design study is projected to the year 2000 technology, substantinal net efficiency improvements, on the order of 25 to 46% over the ASRE, are computed.

  7. Automotive Stirling engine systems development

    NASA Technical Reports Server (NTRS)

    Richey, A. E.

    1984-01-01

    The objective of the Automotive Stirling Engine (ASE) program is to develop a Stirling engine for automotive use that provides a 30 percent improvement in fuel economy relative to a comparable internal-combustion engine while meeting emissions goals. This paper traces the engine systems' development efforts focusing on: (1) a summary of engine system performance for all Mod I engines; (2) the development, program conducted for the upgraded Mod I; and (3) vehicle systems work conducted to enhance vehicle fuel economy. Problems encountered during the upgraded Mod I test program are discussed. The importance of the EPA driving cycle cold-start penalty and the measures taken to minimize that penalty with the Mod II are also addressed.

  8. Stability of split Stirling refrigerators

    NASA Astrophysics Data System (ADS)

    de Waele, A. T. A. M.; Liang, W.

    2009-02-01

    In many thermal systems spontaneous mechanical oscillations are generated under the influence of large temperature gradients. Well-known examples are Taconis oscillations in liquid-helium cryostats and oscillations in thermoacoustic systems. In split Stirling refrigerators the compressor and the cold finger are connected by a flexible tube. The displacer in the cold head is suspended by a spring. Its motion is pneumatically driven by the pressure oscillations generated by the compressor. In this paper we give the basic dynamic equations of split Stirling refrigerators and investigate the possibility of spontaneous mechanical oscillations if a large temperature gradient develops in the cold finger, e.g. during or after cool down. These oscillations would be superimposed on the pressure oscillations of the compressor and could ruin the cooler performance.

  9. Stirling and Vuilleumier heat pumps

    SciTech Connect

    Wurm, J.

    1990-01-01

    The book discuses the design, application, and performance evaluation of integrated engine-refrigerator heat pumps and provides an overview of heat pump theory, including a unique comparative analysis of six integrated Stirling and Vuilleumier heat pumps and their advantages in applications. It also evaluates the effect of key components on performance; lists and documents computer programs for comparative analysis; and summarizes current hardware development programs.

  10. Mod II Stirling engine overviews

    NASA Technical Reports Server (NTRS)

    Farrell, Roger A.

    1988-01-01

    The Mod II engine is a second-generation automotive Stirling engine (ASE) optimized for part-power operation. It has been designed specifically to meet the fuel economy and exhaust emissions objectives of the ASE development program. The design, test experience, performance, and comparison of data to analytical performance estimates of the Mod II engine to date are reviewed. Estimates of Mod II performance in its final configuration are also given.

  11. Automotive Stirling engine development program

    NASA Technical Reports Server (NTRS)

    Nightingale, N.; Ernst, W.; Richey, A.; Simetkosky, M.; Smith, G.; Rohdenburg, C.; Vatsky, A.; Antonelli, M. (Editor)

    1983-01-01

    Activities performed on Mod I engine testing and test results, testing of the Mod I engine in the United States, Mod I engine characterization and analyses, Mod I Transient Test Bed fuel economy, upgraded Mod I performance and testing, Stirling engine reference engine manufacturing and reduced size studied, components and subsystems, and the study and test of low cost casting alloys are summarized. The overall program philosophy is outlined, and data and results are presented.

  12. Automotive Stirling Engine Development Program

    NASA Technical Reports Server (NTRS)

    Nightingale, N.; Ernst, W.; Richey, A.; Simetkosky, M.; Smith, G.; Antonelli, M. (Editor)

    1983-01-01

    Mod I engine testing and test results, the test of a Mod I engine in the United States, Mod I engine characterization and analysis, Mod I Transient Test Bed fuel economy, Mod I-A engine performance are discussed. Stirling engine reference engine manufacturing and reduced size studies, components and subsystems, and the study and test of low-cost casting alloys are also covered. The overall program philosophy is outlined, and data and results are presented.

  13. Joint Radioisotope Electric Propulsion Studies - Neptune System Explorer

    NASA Technical Reports Server (NTRS)

    Khan, M. Omair; Amini, Rashied; Ervin, Joan; Lang, Jared; Landau, Damon; Oleson, Steven; Spilker, Thomas; Strange, Nathan

    2011-01-01

    The Neptune System Explorer (NSE) mission concept study assessed opportunities to conduct Cassini-like science at Neptune with a radioisotope electric propulsion (REP) based spacecraft. REP is based on powering an electric propulsion (EP) engine with a radioisotope power source (RPS). The NSE study was commissioned under the Joint Radioisotope Electric Propulsion Studies (JREPS) project, which sought to determine the technical feasibility of flagship class REP applications. Within JREPS, special emphasis was given toward identifying tall technology tent poles, as well as recommending any new RPS technology developments that would be required for complicated REP missions. Based on the goals of JREPS, multiple RPS (e.g. thermoelectric and Stirling based RPS) and EP (e.g. Hall and ion engines) technology combinations were traded during the NSE study to determine the most favorable REP design architecture. Among the findings from the study was the need for >400We RPS systems, which was driven by EP operating powers and the requirement for a long-lived mission in the deep solar system. Additionally multiple development and implementation risks were identified for the NSE concept, as well as REP missions in general. Among the strengths of the NSE mission would be the benefits associated with RPS and EP use, such as long-term power (approx. 2-3kW) at Neptune and flexible trajectory options for achieving orbit or tours of the Neptune system. Although there are still multiple issues to mitigate, the NSE concept demonstrated distinct advantages associated with using REP for deep space flagship-class missions.

  14. Bellcrank mechanisms for Stirling engines

    SciTech Connect

    Senft, J.R.; Senft, V.J.

    1996-12-31

    This paper describes a family of linkage drive systems for Stirling engines containing several new members. These mechanisms are adaptable to all three configurations of Stirling engine, impose minimal side loads on pistons and displacer rods, and include compact forms suitable for pressurized high performance engines. This group of drive systems is generated by a simple common scheme. Near sinusoidal motion is taken from a crankshaft carrying a single crankpin by two connecting rods each driving a bellcrank. The stationary pivots of the bellcranks are located so that their oscillatory motion has the phase angle separation required between the piston and displacer. The bellcranks are further configured to bring the third pin motion to a location suitable for coupling with the piston or displacer of the engine in a way which minimizes side loading. The paper presents a number of new linkage drives from the dual bellcrank family and indicates how they are embodied in beta and alpha type Stirling engines. The paper includes a design for a small multipurpose engine incorporating one of the subject mechanisms.

  15. Design, Qualification and Integration Testing of the High-Temperature Resistance Temperature Device for Stirling Power System

    NASA Technical Reports Server (NTRS)

    Chan, Jack; Hill, Dennis H.; Elisii, Remo; White, Jonathan R.; Lewandowski, Edward J.; Oriti, Salvatore M.

    2015-01-01

    The Advanced Stirling Radioisotope Generator (ASRG), developed from 2006 to 2013 under the joint sponsorship of the United States Department of Energy (DOE) and National Aeronautics and Space Administration (NASA) to provide a high-efficiency power system for future deep space missions, employed Sunpower Incorporated's Advanced Stirling Convertors (ASCs) with operating temperature up to 840 C. High-temperature operation was made possible by advanced heater head materials developed to increase reliability and thermal-to-mechanical conversion efficiency. During a mission, it is desirable to monitor the Stirling hot-end temperature as a measure of convertor health status and assist in making appropriate operating parameter adjustments to maintain the desired hot-end temperature as the radioisotope fuel decays. To facilitate these operations, a Resistance Temperature Device (RTD) that is capable of high-temperature, continuous long-life service was designed, developed and qualified for use in the ASRG. A thermal bridge was also implemented to reduce the RTD temperature exposure while still allowing an accurate projection of the ASC hot-end temperature. NASA integrated two flight-design RTDs on the ASCs and assembled into the high-fidelity Engineering Unit, the ASRG EU2, at Glenn Research Center (GRC) for extended operation and system characterization. This paper presents the design implementation and qualification of the RTD, and its performance characteristics and calibration in the ASRG EU2 testing.

  16. Automotive Stirling Engine Development Program: A success

    SciTech Connect

    Tabata, W.K.

    1987-01-01

    The original 5 y Automotive Stirling Engine Development Program has been stretched to a 10 y program due to reduced annual funding levels. With an estimated completion date of April 1988, the technical achievements and the prospectives of meeting the original program objectives are reviewed. Various other applications of this developed Stirling engine technology are also discussed.

  17. Recent Stirling engine loss-understanding results

    NASA Technical Reports Server (NTRS)

    Tew, Roy C.; Thieme, Lanny G.; Dudenhoefer, James E.

    1990-01-01

    For several years, NASA and other U.S. government agencies have been funding experimental and analytical efforts to improve the understanding of Stirling thermodynamic losses. NASA's objective is to improve Stirling engine design capability to support the development of new engines for space power. An overview of these efforts was last given at the 1988 IECEC. Recent results of this research are reviewed.

  18. Demonstration Experiments with a Stirling Engine.

    ERIC Educational Resources Information Center

    Deacon, Christopher G.; And Others

    1994-01-01

    Describes an investigation with the primary purpose of allowing students to generate and interpret a pressure/volume diagram of a Stirling engine. Explains how the Stirling engine can be used to demonstrate the principles of operation of a refrigerator and a heat pump. (DDR)

  19. Heat exchanger module for stirling engines

    SciTech Connect

    Darche, M. J. P.; Carlquist, S.

    1985-02-12

    The invention relates to Stirling engines and provides a modular assembly composed of a cylinder head, a heater, a regenerator, a cooler and a cold duct, and making it possible by mounting a plurality of identical modules on an engine assembly to construct a multi-cylinder double acting Stirling engine of the indirect heating type.

  20. A novel experimentally validated Stirling cycle simulation

    SciTech Connect

    Rix, D.H.

    1983-08-01

    This paper presents an entirely new method of Stirling cycle simulation and its application to a laboratory Stirling machine. Specimen predicted results are given for this machine and a comparison is made with results experimentally measured over a wide range of speed and mean pressure values.

  1. Automotive Stirling engine development program - A success

    NASA Technical Reports Server (NTRS)

    Tabata, William K.

    1987-01-01

    The original 5-year Automotive Stirling Engine Development Program has been extended to 10 years due to reduced annual funding levels. With an estimated completion date of April 1988, the technical achievements and the prospectives of meeting the original program objectives are reviewed. Various other applications of this developed Stirling engine technology are also discussed.

  2. Automotive Stirling engine development program: A success

    NASA Technical Reports Server (NTRS)

    Tabata, W. K.

    1987-01-01

    The original 5-yr Automotive Stirling Engine Development Program has been extended to 10 years due to reduced annual funding levels. With an estimated completion date of April 1988, the technical achievements and the prospectives of meeting the original program objectives are reviewed. Various other applications of this developed Stirling engine technology are also discussed.

  3. Solar-Electric Dish Stirling System Development

    SciTech Connect

    Mancini, T.R.

    1997-12-31

    Electrical power generated with the heat from the sun, called solar thermal power, is produced with three types of concentrating solar systems - trough or line-focus systems; power towers in which a centrally-located thermal receiver is illuminated with a large field of sun-tracking heliostats; and dish/engine systems. A special case of the third type of system, a dish/Stirling system, is the subject of this paper. A dish/Stirling system comprises a parabolic dish concentrator, a thermal receiver, and a Stirling engine/generator located at the focus of the dish. Several different dish/Stirling systems have been built and operated during the past 15 years. One system claims the world record for net conversion of solar energy to electric power of 29.4%; and two different company`s systems have accumulated thousands of hours of on-sun operation. Due to de-regulation and intense competition in global energy markets as well as the immaturity of the technology, dish/Stirling systems have not yet found their way into the marketplace. This situation is changing as solar technologies become more mature and manufacturers identify high-value niche markets for their products. In this paper, I review the history of dish/Stirling system development with an emphasis on technical and other issues that directly impact the Stirling engine. I also try to provide some insight to the opportunities and barriers confronting the application of dish/Stirling in power generation markets.

  4. Downsizing assessment of automotive Stirling engines

    NASA Technical Reports Server (NTRS)

    Knoll, R. H.; Tew, R. C., Jr.; Klann, J. L.

    1983-01-01

    A 67 kW (90 hp) Stirling engine design, sized for use in a 1984 1440 kg (3170 lb) automobile was the focal point for developing automotive Stirling engine technology. Since recent trends are towards lighter vehicles, an assessment was made of the applicability of the Stirling technology being developed for smaller, lower power engines. Using both the Philips scaling laws and a Lewis Research Center (Lewis) Stirling engine performance code, dimensional and performance characteristics were determined for a 26 kW (35 hp) and a 37 kW (50 hp) engine for use in a nominal 907 kg (2000 lb) vehicle. Key engine elements were sized and stressed and mechanical layouts were made to ensure mechanical fit and integrity of the engines. Fuel economy estimates indicated that the Stirling engine would maintain a 30 to 45 percent fuel economy advantage comparable spark ignition and diesel powered vehicles in the 1984 period.

  5. Stirling Laboratory Research Engine: Preprototype configuration report

    NASA Technical Reports Server (NTRS)

    Hoehn, F. W.

    1982-01-01

    The concept of a simple Stirling research engine that could be used by industrial, university, and government laboratories was studied. The conceptual and final designs, hardware fabrication and the experimental validation of a preprototype stirling laboratory research engine (SLRE) were completed. Also completed was a task to identify the potential markets for research engines of this type. An analytical effort was conducted to provide a stirling cycle computer model. The versatile engine is a horizontally opposed, two piston, single acting stirling engine with a split crankshaft drive mechanism; special instrumentation is installed at all component interfaces. Results of a thermodynamic energy balance for the system are reported. Also included are the engine performance results obtained over a range of speeds, working pressures, phase angles and gas temperatures. The potential for a stirling research engine to support the laboratory requirements of educators and researchers was demonstrated.

  6. Stirling engine design manual, 2nd edition

    NASA Technical Reports Server (NTRS)

    Martini, W. R.

    1983-01-01

    This manual is intended to serve as an introduction to Stirling cycle heat engines, as a key to the available literature on Stirling engines and to identify nonproprietary Stirling engine design methodologies. Two different fully described Stirling engines are discussed. Engine design methods are categorized as first order, second order, and third order with increased order number indicating increased complexity. FORTRAN programs are listed for both an isothermal second order design program and an adiabatic second order design program. Third order methods are explained and enumerated. In this second edition of the manual the references are updated. A revised personal and corporate author index is given and an expanded directory lists over 80 individuals and companies active in Stirling engines.

  7. Free-piston Stirling engine system considerations for various space power applications

    SciTech Connect

    Dochat, G.R.; Dhar, M. )

    1991-01-05

    The U.S. Government is evaluating power requirements for future space applications. As power requirements increase solar or nuclear dynamic systems become increasingly attractive. Free-Piston Stirling Engines (FPSE) have the potential to provide high reliability, long life, and efficient operation. Therefore, they are excellent candidates for the dynamic power conversion module of a space-based, power-generating system. FPSE can be coupled with many potential heat sources (radioisotope, solar, or nuclear reactor), various heat input systems (pumped loop, heat pipe), heat rejection (pumped loop or heat pipe), and various power management and distribution systems (AC, DC, high or low voltage, and fixed or variable load). This paper will review potential space missions that can be met using free-piston Stirling engines and discusses options of various system integration approaches. Currently free-piston Stirling engine technology for space power applications is being developed under contract with NASA-Lewis Research Center. This paper will also briefly outline the program and recent progress.

  8. Test Hardware Design for Flightlike Operation of Advanced Stirling Convertors (ASC-E3)

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.

    2012-01-01

    NASA Glenn Research Center (GRC) has been supporting development of the Advanced Stirling Radioisotope Generator (ASRG) since 2006. A key element of the ASRG project is providing life, reliability, and performance testing of the Advanced Stirling Convertor (ASC). For this purpose, the Thermal Energy Conversion branch at GRC has been conducting extended operation of a multitude of free-piston Stirling convertors. The goal of this effort is to generate long-term performance data (tens of thousands of hours) simultaneously on multiple units to build a life and reliability database. The test hardware for operation of these convertors was designed to permit in-air investigative testing, such as performance mapping over a range of environmental conditions. With this, there was no requirement to accurately emulate the flight hardware. For the upcoming ASC-E3 units, the decision has been made to assemble the convertors into a flight-like configuration. This means the convertors will be arranged in the dual-opposed configuration in a housing that represents the fit, form, and thermal function of the ASRG. The goal of this effort is to enable system level tests that could not be performed with the traditional test hardware at GRC. This offers the opportunity to perform these system-level tests much earlier in the ASRG flight development, as they would normally not be performed until fabrication of the qualification unit. This paper discusses the requirements, process, and results of this flight-like hardware design activity.

  9. Test Hardware Design for Flight-Like Operation of Advanced Stirling Convertors

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.

    2012-01-01

    NASA Glenn Research Center (GRC) has been supporting development of the Advanced Stirling Radioisotope Generator (ASRG) since 2006. A key element of the ASRG project is providing life, reliability, and performance testing of the Advanced Stirling Convertor (ASC). For this purpose, the Thermal Energy Conversion branch at GRC has been conducting extended operation of a multitude of free-piston Stirling convertors. The goal of this effort is to generate long-term performance data (tens of thousands of hours) simultaneously on multiple units to build a life and reliability database. The test hardware for operation of these convertors was designed to permit in-air investigative testing, such as performance mapping over a range of environmental conditions. With this, there was no requirement to accurately emulate the flight hardware. For the upcoming ASC-E3 units, the decision has been made to assemble the convertors into a flight-like configuration. This means the convertors will be arranged in the dual-opposed configuration in a housing that represents the fit, form, and thermal function of the ASRG. The goal of this effort is to enable system level tests that could not be performed with the traditional test hardware at GRC. This offers the opportunity to perform these system-level tests much earlier in the ASRG flight development, as they would normally not be performed until fabrication of the qualification unit. This paper discusses the requirements, process, and results of this flight-like hardware design activity.

  10. The Electromagnetic Compatibility (EMC) Design Challenge for Scientific Spacecraft Powered by a Stirling Power Converter

    NASA Technical Reports Server (NTRS)

    Sargent, Noel B.

    2001-01-01

    A 55 We free-piston Stirling Technology Demonstration Convertor (TDC) has been tested as part of an evaluation to determine its feasibility as a means for significantly reducing the amount of radioactive material required compared to Radioisotope Thermoelectric Generators (RTGs) to support long-term space science missions. Measurements were made to quantify the low frequency magnetic and electric fields radiated from the Stirling's 80 Hertz (Hz) linear alternator and control electronics in order to determine the magnitude of reduction that will be required to protect sensitive field sensors aboard some science missions. One identified "Solar Probe" mission requires a 100 dB reduction in the low frequency magnetic field over typical military standard design limits, to protect its plasma wave sensor. This paper discusses the electromagnetic interference (EMI) control options relative to the physical design impacts for this power system, composed of 3 basic electrical elements. They are (1) the Stirling Power Convertor with its linear alternator, (2) the power switching and control electronics to convert the 90 V, 80 Hz alternator output to DC for the use of the spacecraft, and (3) the interconnecting wiring including any instrumentation to monitor and control items 1 and 2.

  11. Test Rack Development for Extended Operation of Advanced Stirling Convertors at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Dugala, Gina M.

    2009-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Space Company (LMSC), Sun power Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for use as a power system on space science missions. This generator will make use of free-piston Stirling convertors to achieve higher conversion efficiency than currently available alternatives. NASA GRC's support of ASRG development includes extended operation testing of Advanced Stirling Convertors (ASCs) developed by Sunpower Inc. In the past year, NASA GRC has been building a test facility to support extended operation of a pair of engineering level ASCs. Operation of the convertors in the test facility provides convertor performance data over an extended period of time. Mechanical support hardware, data acquisition software, and an instrumentation rack were developed to prepare the pair of convertors for continuous extended operation. Short-term tests were performed to gather baseline performance data before extended operation was initiated. These tests included workmanship vibration, insulation thermal loss characterization, low-temperature checkout, and fUll-power operation. Hardware and software features are implemented to ensure reliability of support systems. This paper discusses the mechanical support hardware, instrumentation rack, data acquisition software, short-term tests, and safety features designed to support continuous unattended operation of a pair of ASCs.

  12. Processing and Preparation of Advanced Stirling Convertors for Extended Operation at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Cornell, Peggy A.

    2008-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Space Company (LMSC), Sunpower Inc., and NASA Glenn Research Center (GRC) have been developing an Advanced Stirling Radioisotope Generator (ASRG) for use as a power system on space science missions. This generator will make use of the free-piston Stirling convertors to achieve higher conversion efficiency than currently available alternatives. NASA GRC is supporting the development of the ASRG by providing extended operation of several Sunpower Inc. Advanced Stirling Convertors (ASCs). In the past year and a half, eight ASCs have operated in continuous, unattended mode in both air and thermal vacuum environments. Hardware, software, and procedures were developed to prepare each convertor for extended operation with intended durations on the order of tens of thousands of hours. Steps taken to prepare a convertor for long-term operation included geometry measurements, thermocouple instrumentation, evaluation of working fluid purity, evacuation with bakeout, and high purity charge. Actions were also taken to ensure the reliability of support systems, such as data acquisition and automated shutdown checkouts. Once a convertor completed these steps, it underwent short-term testing to gather baseline performance data before initiating extended operation. These tests included insulation thermal loss characterization, low-temperature checkout, and full-temperature and power demonstration. This paper discusses the facilities developed to support continuous, unattended operation, and the processing results of the eight ASCs currently on test.

  13. Design of small Stirling Dynamic Isotope Power System for robotic space missions

    NASA Astrophysics Data System (ADS)

    Bents, David J.; Schreiber, Jeffrey G.; Withrow, Colleen A.; McKissock, Barbara I.; Schmitz, Paul C.

    1993-01-01

    Design of a multihundred-watt Dynamic Isotope Power System (DIPS) based on the U.S. Department of Energy (DOE) General Purpose Heat Source (GPHS) and small (multihundred-watt) free-piston Stirling engine (FPSE) technology is being pursued as a potential lower cost alternative to radioisotope thermoelectric generator (RTG's). The design is targeted at the power needs of future unmanned deep space and planetary surface exploration missions ranging from scientific probes to Space Exploration Initiative precursor missions. Power level for these missions is less than a kilowatt. Unlike previous DIPS designs which were based on turbomachinery conversion (e.g. Brayton), this small Stirling DIPS can be advantageously scaled down to multihundred-watt unit size while preserving size and mass competitiveness with RTGs. Preliminary characterization of units in the output power ranges 200-600 We indicate that on an electrical watt basis the GPHS/small Stirling DIPS will be roughly equivalent to an advanced RTG in size and mass but require less than a third of the isotope inventory.

  14. Incorporating Vibration Test Results for the Advanced Stirling Convertor into the System Dynamic Model

    NASA Technical Reports Server (NTRS)

    Meer, David W.; Lewandowski, Edward J.

    2010-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin Corporation (LM), and NASA Glenn Research Center (GRC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. As part of the extended operation testing of this power system, the Advanced Stirling Convertors (ASC) at NASA GRC undergo a vibration test sequence intended to simulate the vibration history that an ASC would experience when used in an ASRG for a space mission. During these tests, a data system collects several performance-related parameters from the convertor under test for health monitoring and analysis. Recently, an additional sensor recorded the slip table position during vibration testing to qualification level. The System Dynamic Model (SDM) integrates Stirling cycle thermodynamics, heat flow, mechanical mass, spring, damper systems, and electrical characteristics of the linear alternator and controller. This Paper presents a comparison of the performance of the ASC when exposed to vibration to that predicted by the SDM when exposed to the same vibration.

  15. Design of small Stirling dynamic isotope power system for robotic space missions

    NASA Technical Reports Server (NTRS)

    Bents, D. J.; Schreiber, J. G.; Withrow, C. A.; Mckissock, B. I.; Schmitz, P. C.

    1992-01-01

    Design of a multihundred-watt Dynamic Isotope Power System (DIPS) based on the U.S. Department of Energy (DOE) General Purpose Heat Source (GPHS) and small (multihundred-watt) free-piston Stirling engine (FPSE) technology is being pursued as a potential lower cost alternative to radioisotope thermoelectric generators (RTG's). The design is targeted at the power needs of future unmanned deep space and planetary surface exploration missions ranging from scientific probes to Space Exploration Initiative precursor missions. Power level for these missions is less than a kilowatt. Unlike previous DIPS designs which were based on turbomachinery conversion (e.g. Brayton), this small Stirling DIPS can be advantageously scaled down to multihundred-watt unit size while preserving size and mass competitiveness with RTG's. Preliminary characterization of units in the output power ranges 200-600 We indicate that on an electrical watt basis the GPHS/small Stirling DIPS will be roughly equivalent to an advanced RTG in size and mass but require less than a third of the isotope inventory.

  16. Advanced Stirling Convertor (ASC) - From Technology Development to Future Flight Product

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Wood, J. Gary; Wilson, Kyle

    2008-01-01

    The Advanced Stirling Convertor (ASC) is being developed by Sunpower, Inc. under contract to NASA s Glenn Research Center (GRC) with critical technology support tasks lead by GRC. The ASC development, funded by NASA s Science Mission Directorate, started in 2003 as one of 10 competitively awarded contracts that were to address future Radioisotope Power System (RPS) advanced power conversion needs. The ASC technology has since evolved through progressive convertor builds and successful testing to demonstrate high conversion efficiency (38 %), low mass (1.3 kg), hermetic sealing, launch vibration simulation, EMI characterization, and is undergoing extended operation. The GRC and Sunpower team recently delivered three ASC-E machines to the Department of Energy (DOE) and Lockheed Martin Space Systems Company, two units for integration onto the Advanced Stirling Radioisotope Generator Engineering Unit (ASRG EU) plus one spare. The design has recently been initiated for the ASC-E2, an evolution from the ASC-E that substitutes higher temperature materials enabling improved performance and higher reliability margins. This paper summarizes the history and status of the ASC project and discusses plans for this technology which enables RPS specific power of 8 W/kg for future NASA missions.

  17. Advanced Stirling Convertor (ASC)--From Technology Development to Future Flight Product

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Wood, J. Gary; Wilson, Kyle

    2008-01-01

    The Advanced Stirling Convertor (ASC) is being developed by Sunpower Inc. under contract to NASA s Glenn Research Center (GRC) with critical technology support tasks led by GRC. The ASC development, funded by NASA s Science Mission Directorate, started in 2003 as one of 10 competitively awarded contracts that were intended to address the power conversion needs of future Radioisotope Power Systems (RPS). The ASC technology has since evolved through progressive convertor builds and successful testing to demonstrate high conversion efficiency (38 percent), low mass (1.3 kg), hermetic sealing, launch vibration simulation, EMI characterization, and is undergoing extended operation. The GRC and Sunpower team recently delivered two ASC-E convertors to the Department of Energy (DOE) and Lockheed Martin Space Systems Company for integration onto the Advanced Stirling Radioisotope Generator Engineering Unit (ASRG EU) plus one spare. The design of the next build, called the ASC-E2, has recently been initiated and is based on the heritage ASC-E with design refinements to increase reliability margin and offer higher temperature operation and improve performance. The ASC enables RPS system specific power of about 7 to 8 W/kg. This paper provides a chronology of ASC development to date and summarizes technical achievements including advancements toward flight implementation of the technology on ASRG by as early as 2013.

  18. Thermal Analysis of Step 2 GPHS for Next Generation Radioisotope Power Source Missions

    NASA Astrophysics Data System (ADS)

    Pantano, David R.; Hill, Dennis H.

    2005-02-01

    The Step 2 General Purpose Heat Source (GPHS) is a slightly larger and more robust version of the heritage GPHS modules flown on previous Radioisotope Thermoelectric Generator (RTG) missions like Galileo, Ulysses, and Cassini. The Step 2 GPHS is to be used in future small radioisotope power sources, such as the Stirling Radioisotope Generator (SRG110) and the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). New features include an additional central web of Fine Weave Pierced Fabric (FWPF) graphite in the aeroshell between the two Graphite Impact Shells (GIS) to improve accidental reentry and impact survivability and an additional 0.1-inch of thickness to the aeroshell broad faces to improve ablation protection. This paper details the creation of the thermal model using Thermal Desktop and AutoCAD interfaces and provides comparisons of the model to results of previous thermal analysis models of the heritage GPHS. The results of the analysis show an anticipated decrease in total thermal gradient from the aeroshell to the iridium clads compared to the heritage results. In addition, the Step 2 thermal model is investigated under typical SRG110 boundary conditions, with cover gas and gravity environments included where applicable, to provide preliminary guidance for design of the generator. Results show that the temperatures of the components inside the GPHS remain within accepted design limits during all envisioned mission phases.

  19. Environmental Loss Characterization of an Advanced Stirling Convertor (ASC-E2) Insulation Package Using a Mock Heater Head

    NASA Technical Reports Server (NTRS)

    Schifer, Nicholas A.; Briggs, Maxwell H.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two highefficiency Advanced Stirling Convertors (ASCs), developed by Sunpower Inc. and NASA Glenn Research Center (GRC). As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a specified electrical power output for a given net heat input. While electrical power output can be precisely quantified, thermal power input to the Stirling cycle cannot be directly measured. In an effort to improve net heat input predictions, the Mock Heater Head was developed with the same relative thermal paths as a convertor using a conducting rod to represent the Stirling cycle and tested to provide a direct comparison to numerical and empirical models used to predict convertor net heat input. The Mock Heater Head also served as the pathfinder for a higher fidelity version of validation test hardware, known as the Thermal Standard. This paper describes how the Mock Heater Head was tested and utilized to validate a process for the Thermal Standard.

  20. Advanced Stirling Convertor Heater Head Durability and Reliability Quantification

    NASA Technical Reports Server (NTRS)

    Krause, David L.; Shah, Ashwin R.; Korovaichuk, Igor; Kalluri, Sreeramesh

    2008-01-01

    The National Aeronautics and Space Administration (NASA) has identified the high efficiency Advanced Stirling Radioisotope Generator (ASRG) as a candidate power source for long duration Science missions, such as lunar applications, Mars rovers, and deep space missions, that require reliable design lifetimes of up to 17 years. Resistance to creep deformation of the MarM-247 heater head (HH), a structurally critical component of the ASRG Advanced Stirling Convertor (ASC), under high temperatures (up to 850 C) is a key design driver for durability. Inherent uncertainties in the creep behavior of the thin-walled HH and the variations in the wall thickness, control temperature, and working gas pressure need to be accounted for in the life and reliability prediction. Due to the availability of very limited test data, assuring life and reliability of the HH is a challenging task. The NASA Glenn Research Center (GRC) has adopted an integrated approach combining available uniaxial MarM-247 material behavior testing, HH benchmark testing and advanced analysis in order to demonstrate the integrity, life and reliability of the HH under expected mission conditions. The proposed paper describes analytical aspects of the deterministic and probabilistic approaches and results. The deterministic approach involves development of the creep constitutive model for the MarM-247 (akin to the Oak Ridge National Laboratory master curve model used previously for Inconel 718 (Special Metals Corporation)) and nonlinear finite element analysis to predict the mean life. The probabilistic approach includes evaluation of the effect of design variable uncertainties in material creep behavior, geometry and operating conditions on life and reliability for the expected life. The sensitivity of the uncertainties in the design variables on the HH reliability is also quantified, and guidelines to improve reliability are discussed.

  1. A Computational Methodology for Simulating Thermal Loss Testing of the Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Reid, Terry V.; Wilson, Scott D.; Schifer, Nicholas A.; Briggs, Maxwell H.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two highefficiency Advanced Stirling Convertors (ASCs), developed by Sunpower Inc. and NASA Glenn Research Center (GRC). The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot end and cold end temperatures, and specified electrical power output for a given net heat input. In an effort to improve net heat input predictions, numerous tasks have been performed which provided a more accurate value for net heat input into the ASCs, including the use of multidimensional numerical models. Validation test hardware has also been used to provide a direct comparison of numerical results and validate the multi-dimensional numerical models used to predict convertor net heat input and efficiency. These validation tests were designed to simulate the temperature profile of an operating Stirling convertor and resulted in a measured net heat input of 244.4 W. The methodology was applied to the multi-dimensional numerical model which resulted in a net heat input of 240.3 W. The computational methodology resulted in a value of net heat input that was 1.7 percent less than that measured during laboratory testing. The resulting computational methodology and results are discussed.

  2. Overview of Heat Addition and Efficiency Predictions for an Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Wilson, Scott D.; Reid, Terry V.; Schifer, Nicholas A.; Briggs, Maxwell H.

    2012-01-01

    The U.S. Department of Energy (DOE) and Lockheed Martin Space Systems Company (LMSSC) have been developing the Advanced Stirling Radioisotope Generator (ASRG) for use as a power system for space science missions. This generator would use two high-efficiency Advanced Stirling Convertors (ASCs), developed by Sunpower Inc. and NASA Glenn Research Center (GRC). The ASCs convert thermal energy from a radioisotope heat source into electricity. As part of ground testing of these ASCs, different operating conditions are used to simulate expected mission conditions. These conditions require achieving a particular operating frequency, hot end and cold end temperatures, and specified electrical power output for a given net heat input. Microporous bulk insulation is used in the ground support test hardware to minimize the loss of thermal energy from the electric heat source to the environment. The insulation package is characterized before operation to predict how much heat will be absorbed by the convertor and how much will be lost to the environment during operation. In an effort to validate these predictions, numerous tasks have been performed, which provided a more accurate value for net heat input into the ASCs. This test and modeling effort included: (a) making thermophysical property measurements of test setup materials to provide inputs to the numerical models, (b) acquiring additional test data that was collected during convertor tests to provide numerical models with temperature profiles of the test setup via thermocouple and infrared measurements, (c) using multidimensional numerical models (computational fluid dynamics code) to predict net heat input of an operating convertor, and (d) using validation test hardware to provide direct comparison of numerical results and validate the multidimensional numerical models used to predict convertor net heat input. This effort produced high fidelity ASC net heat input predictions, which were successfully validated using

  3. Structural analyses of Stirling power-convertor heater head for long-term reliability, durability, and performance

    NASA Astrophysics Data System (ADS)

    Halford, Gary R.; Shah, Ashwin; Arya, Vinod K.; Krause, David L.; Bartolotta, Paul A.

    2002-01-01

    Deep space missions require onboard electric power systems with reliable design lifetimes of up to 10-y and beyond. A high-efficiency Stirling radioisotope power system is a prime candidate for future deep space missions and Mars rover applications. To ensure ample durability, the structurally critical Heater Head of the Stirling Power-Convertor has undergone extensive computational analyses of operating temperatures (up to 650 °C), stresses, and creep-resistance of the thin-walled Inconel 718 bill-of-material. Durability predictions are presented in terms of probability of survival. A benchmark structural testing program has commenced to support the analyses. This paper reports the current status of our durability assessments. .

  4. Solar powered Stirling cycle electrical generator

    NASA Astrophysics Data System (ADS)

    Shaltens, Richard K.

    1991-03-01

    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.

  5. Stirling Engine for Classroom Demonstration Purposes

    NASA Astrophysics Data System (ADS)

    Miller, Andrew

    2005-04-01

    In the study of Thermodynamics, the Carnot cycle is representative of an ideal engine. Such an engine has the maximum efficiency possible for a given temperature difference. The Stirling Cycle engine closely resembles the Carnot cycle in terms of efficiency. In order to demonstrate the Stirling Cycle in a classroom setting, a Stirling engine was built. Robert Stirling first patented the Stirling engine in 1816. The Stirling engine runs on the temperature differential between hot and cold air. As the air is cycled through the engine, the expansion and contraction of the air drives the piston. The work on the piston is transferred into mechanical work via a walking beam. There are no exhaust values that vent gases, because the gases inside the engine never leave. The power for the Stirling engine does not come from explosions like a combustion engine. Rather, the engine is powered by an external heat source. These engines also have practical purposes. They are used in very specialized applications where quiet operation is important. Examples of such uses are in submarines and auxiliary power generators.

  6. 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.

  7. Liquid-piston Stirling machines

    SciTech Connect

    West, C.D.

    1984-01-01

    Since the invention of the Fluidyne engine in 1969, several research groups have explored and described the potential of liquid-piston Stirling machine designs for a wide variety of applications, including water pumping from solar heat, simple and long-lived fossil-fuel-fired irrigation pumps, and heat-powered heat pumps. A substantial amount of theoretical work has been published, along with experimental results from a number of very different machines and design data for the construction of experimental engines. This paper describes the progress that has been made and the performance of existing systems, identifies outstanding research needs, and outlines some of the potential for further progress.

  8. Mod I automotive Stirling engine mechanical development

    SciTech Connect

    Simetkosky, M.

    1984-01-01

    The Mod I Stirling engine was the first automotive Stirling engine designed specifically for automotive application. Testing of these engines has revealed several deficiencies in engine mechanical integrity which have been corrected by redesign or upgrade. The main deficiencies uncovered during the Mod I program lie in the combustion, auxiliary, main seal, and heater head areas. This paper will address each of the major area deficiencies in detail, and describe the corrective actions taken as they apply to the Mod I and the next Stirling-engine design, the Upgraded Mod I (a redesign to incorporate new materials for cost/weight reduction and improved performance).

  9. Rotary Stirling-Cycle Engine And Generator

    NASA Technical Reports Server (NTRS)

    Chandler, Joseph A.

    1990-01-01

    Proposed electric-power generator comprises three motor generators coordinated by microprocessor and driven by rotary Stirling-cycle heat engine. Combination offers thermodynamic efficiency of Stirling cycle, relatively low vibration, and automatic adjustment of operating parameters to suit changing load on generator. Rotary Stirling cycle engine converts heat to power via compression and expansion of working gas between three pairs of rotary pistons on three concentric shafts in phased motion. Three motor/generators each connected to one of concentric shafts, can alternately move and be moved by pistons. Microprocessor coordinates their operation, including switching between motor and generator modes at appropriate times during each cycle.

  10. Automotive Stirling Engine Development Project

    NASA Technical Reports Server (NTRS)

    Ernst, William D.; Shaltens, Richard K.

    1997-01-01

    The development and verification of automotive Stirling engine (ASE) component and system technology is described as it evolved through two experimental engine designs: the Mod 1 and the Mod 2. Engine operation and performance and endurance test results for the Mod 1 are summarized. Mod 2 engine and component development progress is traced from the original design through hardware development, laboratory test, and vehicle installation. More than 21,000 hr of testing were accomplished, including 4800 hr with vehicles that were driven more dm 59,000 miles. Mod 2 engine dynamometer tests demonstrated that the engine system configuration had accomplished its performance goals for power (60 kW) and efficiency (38.5%) to within a few percent. Tests with the Mod 2 engine installed in a delivery van demonstrated combined metro-highway fuel economy improvements consistent with engine performance goals and the potential for low emission levels. A modified version of the Mod 2 has been identified as a manufacturable design for an ASE. As part of the ASE project, the Industry Test and Evaluation Program (ITEP), NASA Technology Utilization (TU) project, and the industry-funded Stirling Natural Gas Engine program were undertaken to transfer ASE technology to end users. The results of these technology transfer efforts are also summarized.

  11. A thermoacoustic Stirling heat engine

    NASA Astrophysics Data System (ADS)

    Backhaus, S.; Swift, G. W.

    1999-05-01

    Electrical and mechanical power, together with other forms of useful work, are generated worldwide at a rate of about 1012 watts, mostly using heat engines. The efficiency of such engines is limited by the laws of thermodynamics and by practical considerations such as the cost of building and operating them. Engines with high efficiency help to conserve fossil fuels and other natural resources, reducing global-warming emissions and pollutants. In practice, the highest efficiencies are obtained only in the most expensive, sophisticated engines, such as the turbines in central utility electrical plants. Here we demonstrate an inexpensive thermoacoustic engine that employs the inherently efficient Stirling cycle. The design is based on a simple acoustic apparatus with no moving parts. Our first small laboratory prototype, constructed using inexpensive hardware (steel pipes), achieves an efficiency of 0.30, which exceeds the values of 0.10-0.25 attained in other heat engines, with no moving parts. Moreover, the efficiency of our prototype is comparable to that of the common internal combustion engine (0.25-0.40) and piston-driven Stirling engines, (0.20-0.38).

  12. Rebirth of the stirling engine

    SciTech Connect

    Sternlicht, B.

    1983-01-01

    Revived interest in external combustion is attributed to such advantages as ability to use a variety of energy sources, high system efficiency and low pollution. A relatively high weight-power ratio, which is undesirable in propulsion applications, and manufacturing costs that have not yet been refined are the two remaining technological challenges. A diagram explaining the Stirling cycle is presened. It is revealed that the first-generation automotive engine (MOD I), which is now being tested, has efficiency in most of the operating ranges that exceeds the analytical predictions that were incorporated into the design. The engine's power density has been improved by 35%. MOD II, which is the second-generation engine and represents the conclusion of the program in 1985, is expected to have 50% fuel economy improvement. This is considerably greater than the 30% currently specified, and the engine weight is expected to be about 5 lb/hp, which is comparable to the weight of diesel engines. It is also expected to meet or surpass both the emission and noise standards. It is concluded that whether the automotive industry will choose the Stirling engine or the gas turbine as its prime mover will depend on a variety of factors, of which technology is only one.

  13. How to Handle Radioisotopes Safely.

    ERIC Educational Resources Information Center

    Sulcoski, John W.

    This booklet is one in a series of instructional aids designed for use by elementary and secondary school science teachers. The various units and forms of radioactive materials used by teachers are first considered. Then, the quantities of radioisotopes that a person may possess without a license from the Atomic Energy Commission (AEC) are…

  14. Simple and Clear Proofs of Stirling's Formula

    ERIC Educational Resources Information Center

    Niizeki, Shozo; Araki, Makoto

    2010-01-01

    The purpose of our article is to show two simpler and clearer methods of proving Stirling's formula than the traditional and conventional ones. The distinction of our method is to use the simple trapezoidal formula.

  15. On the Need for Multidimensional Stirling Simulations

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger W.; Wilson, Scott D.; Tew, Roy C.; Demko, Rikako

    2005-01-01

    Given the cost and complication of simulating Stirling convertors, do we really need multidimensional modeling when one-dimensional capabilities exist? This paper provides a comprehensive description of when and why multidimensional simulation is needed.

  16. Stirling engine research at Argonne National Laboratory

    SciTech Connect

    Holtz, R.E.; Daley, J.G.; Roach, P.D.

    1986-06-01

    Stirling engine research at Argonne National Laboratory has been focused at (1) development of mathematical models and analytical tools for predicting component and engine performance, and (2) experimental research into fundamental heat transfer and fluid flow phenomena occurring in Stirling cycle devices. A result of the analytical effort has been the formation of a computer library specifically for Stirling engine researchers and developers. The library contains properties of structural materials commonly used, thermophysical properties of several working fluids, correlations for heat transfer calculations and general specifications of mechanical arrangements (including various drive mechanisms) that can be utilized to model a particular engine. The library also contains alternative modules to perform analysis at different levels of sophistication, including design optimization. A reversing flow heat transfer facility is operating at Argonne to provide data at prototypic Stirling engine operating conditions under controlled laboratory conditions. This information is needed to validate analytical models.

  17. Heater head for a Stirling engine

    SciTech Connect

    Darooka, D.K.

    1988-09-06

    A heater head is described for a compound Stirling engine modules, each including a displacer cylinder coaxially aligned with the displacer cylinder of the other of the engine modules, a displacer piston mounted for reciprocation in the displacer cylinder.

  18. Automotive Stirling engine: Mod 2 design report

    NASA Technical Reports Server (NTRS)

    Nightingale, Noel P.

    1986-01-01

    The design of an automotive Stirling engine that achieves the superior fuel economy potential of the Stirling cycle is described. As the culmination of a 9-yr development program, this engine, designated the Mod 2, also nullifies arguments that Stirling engines are heavy, expensive, unreliable, demonstrating poor performance. Installed in a General Motors Chevrolet Celebrity car, this engine has a predicted combined fuel economy on unleaded gasoline of 17.5 km/l (41 mpg)- a value 50% above the current vehicle fleet average. The Mod 2 Stirling engine is a four-cylinder V-drive design with a single crankshaft. The engine is also equipped with all the controls and auxiliaries necessary for automotive operation.

  19. Review of Computational Stirling Analysis Methods

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger W.; Wilson, Scott D.; Tew, Roy C.

    2004-01-01

    Nuclear thermal to electric power conversion carries the promise of longer duration missions and higher scientific data transmission rates back to Earth for both Mars rovers and deep space missions. A free-piston Stirling convertor is a candidate technology that is considered an efficient and reliable power conversion device for such purposes. While already very efficient, it is believed that better Stirling engines can be developed if the losses inherent its current designs could be better understood. However, they are difficult to instrument and so efforts are underway to simulate a complete Stirling engine numerically. This has only recently been attempted and a review of the methods leading up to and including such computational analysis is presented. And finally it is proposed that the quality and depth of Stirling loss understanding may be improved by utilizing the higher fidelity and efficiency of recently developed numerical methods. One such method, the Ultra HI-Fl technique is presented in detail.

  20. Stirling Air Conditioner for Compact Cooling

    SciTech Connect

    2010-09-01

    BEETIT Project: Infinia is developing a compact air conditioner that uses an unconventional high efficient Stirling cycle system (vs. conventional vapor compression systems) to produce cool air that is energy efficient and does not rely on polluting refrigerants. The Stirling cycle system is a type of air conditioning system that uses a motor with a piston to remove heat to the outside atmosphere using a gas refrigerant. To date, Stirling systems have been expensive and have not had the right kind of heat exchanger to help cool air efficiently. Infinia is using chip cooling technology from the computer industry to make improvements to the heat exchanger and improve system performance. Infinia’s air conditioner uses helium gas as refrigerant, an environmentally benign gas that does not react with other chemicals and does not burn. Infinia’s improvements to the Stirling cycle system will enable the cost-effective mass production of high-efficiency air conditioners that use no polluting refrigerants.

  1. Anatomy of the Stirling engine cycle

    NASA Astrophysics Data System (ADS)

    Organ, A. J.

    Conditions are isolated for thermodynamic processes in two Stirling cycle machines to be identical. The conditions form the basis for the concept of 'functional similarity'. Using the similarity conditions the designer may scale the detailed gas circuit specification of a viable Stirling engine to a derivative design of different size, crankshaft speed, working fluid and pressure. The method complements, and provides an independent check of, the simulation approach to gas circuit design.

  2. Demonstration experiments with a Stirling engine

    NASA Astrophysics Data System (ADS)

    Deacon, Christopher G.; Goulding, Richard; Haridass, C.; de Young, Brad

    1994-05-01

    Heat engines are used in teaching thermodynamics as ideas to develop theory and real things to illustrate working thermodynamic principles. The Stirling engine combines both possibilities. We use it as a tool to illustrate some basic thermodynamic principles; to show the characteristics of a heat engine and interpret a pV diagram. We also show how the Stirling engine can be used to demonstrate the principles of operation of a refrigerator and heat pump.

  3. Materials technology assessment for stirling engines

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Witzke, W. R.; Watson, G. K.; Johnston, J. R.; Croft, W. J.

    1977-01-01

    A materials technology assessment of high temperature components in the improved (metal) and advanced (ceramic) Stirling engines was undertaken to evaluate the current state-of-the-art of metals and ceramics, identify materials research and development required to support the development of automotive Stirling engines, and to recommend materials technology programs to assure material readiness concurrent with engine system development programs. The most critical component for each engine is identified and some of the material problem areas are discussed.

  4. Recent Stirling engine loss - understanding results

    SciTech Connect

    Tew, R.C.; Thieme, L.G.; Dudenhoefer, J.E.

    1994-09-01

    For several years, the National Aeronautics and Space Administration and other US Government agencies have been funding experimental and analytical efforts to improve the understanding of Stirling thermodynamic losses. NASA`s objective is to improve Stirling engine design capability to support the development of new engines for space power. An overview of these efforts was last given at the 1988 IECEC. Recent results of this research are reviewed.

  5. Automotive Stirling Engine Development Program Mod I Stirling engine development

    NASA Technical Reports Server (NTRS)

    Simetkosky, M. A.

    1983-01-01

    The development of the Mod I 4-cylinder automotive Stirling engine is discussed and illustrated with drawings, block diagrams, photographs, and graphs and tables of preliminary test data. The engine and its drive, cold-engine, hot-engine, external-heat, air/fuel, power-control, electronic-control, and auxiliary systems are characterized. Performance results from a total of 1900 h of tests on 4 prototype engines include average maximum efficiency (at 2000 rpm) 34.5 percent and maximum output power 54.4 kW. The modifications introduced in an upgraded version of the Mod I are explained; this engine has maximum efficiency 40.4 percent and maximum power output 69.2 kW.

  6. ENHANCED THERMAL VACUUM TEST CAPABILITY FOR RADIOISOTOPE POWER SYSTEMS AT THE IDAHO NATIONAL LABORATORY BETTER SIMULATES ENVIRONMENTAL CONDITIONS OF SPACE

    SciTech Connect

    J. C. Giglio; A. A. Jackson

    2012-03-01

    The Idaho National Laboratory (INL) is preparing to fuel and test the Advanced Stirling Radioisotope Generator (ASRG), the next generation space power generator. The INL identified the thermal vacuum test chamber used to test past generators as inadequate. A second vacuum chamber was upgraded with a thermal shroud to process the unique needs and to test the full power capability of the new generator. The thermal vacuum test chamber is the first of its kind capable of testing a fueled power system to temperature that accurately simulate space. This paper outlines the new test and set up capabilities at the INL.

  7. Radioisotope thermophotovoltaic system design and its application to an illustrative space mission

    SciTech Connect

    Schock, A.; Kumar, V.

    1995-01-05

    The paper describes the results of a DOE-sponsored design study of a radioisotope thermophotovoltaic generator (RTPV), to complement similar studies of Radioisotope Thermoelectric Generators (RTGs) and Stirling Generators (RSGs) previously published by the author. Instead of conducting a generic study, it was decided to focus the design effort by directing it at a specific illustrative space mission, Pluto Fast Flyby (PFF). That mission, under study by JPL, envisages a direct eight-year flight to Pluto (the only unexplored planet in the solar system), followed by comprehensive mapping, surface composition, and atmospheric structure measurements during a brief flyby of the planet and its moon Charon, and transmission of the recorded science data to Earth during a post-encounter cruise lasting up to one year. Because of Pluto`s long distance from the sun (30--50 A.U.) and the mission`s large energy demand, JPL has baselined the use of a radioisotope power system for the PFF spacecraft. TRGs have been tentatively selected, because they have been successfully flown on many space missions, and have demonstrated exceptional reliability and durability. The only reason for exploring the applicability of the far less mature RTPV systems is their potential for much higher conversion efficiencies, which would greatly reduce the mass and cost of the required radioisotope heat source. Those attributes are particularly important for the PFF mission, which---like all NASA missions under current consideration---is severely mass- and cost-limited. The paper describes the design of the radioisotope heat source, the thermophotovoltaic converter, and the heat rejection system; and depicts its integration with the PFF spacecraft.

  8. STIRLING'S QUARTERS SMALL BARN: FIRST FLOOR PLAN; SECOND FLOOR PLAN; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    STIRLING'S QUARTERS SMALL BARN: FIRST FLOOR PLAN; SECOND FLOOR PLAN; SOUTH ELEVATION; EAST ELEVATION; NORTH ELEVATION; WEST ELEVATION. - Stirling's Quarters, 555 Yellow Springs Road, Tredyffrin Township, Valley Forge, Chester County, PA

  9. Reliability-Based Life Assessment of Stirling Convertor Heater Head

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin R.; Halford, Gary R.; Korovaichuk, Igor

    2004-01-01

    Onboard radioisotope power systems being developed and planned for NASA's deep-space missions require reliable design lifetimes of up to 14 yr. The structurally critical heater head of the high-efficiency Stirling power convertor has undergone extensive computational analysis of operating temperatures, stresses, and creep resistance of the thin-walled Inconel 718 bill of material. A preliminary assessment of the effect of uncertainties in the material behavior was also performed. Creep failure resistance of the thin-walled heater head could show variation due to small deviations in the manufactured thickness and in uncertainties in operating temperature and pressure. Durability prediction and reliability of the heater head are affected by these deviations from nominal design conditions. Therefore, it is important to include the effects of these uncertainties in predicting the probability of survival of the heater head under mission loads. Furthermore, it may be possible for the heater head to experience rare incidences of small temperature excursions of short duration. These rare incidences would affect the creep strain rate and, therefore, the life. This paper addresses the effects of such rare incidences on the reliability. In addition, the sensitivities of variables affecting the reliability are quantified, and guidelines developed to improve the reliability are outlined. Heater head reliability is being quantified with data from NASA Glenn Research Center's accelerated benchmark testing program.

  10. Update on the advanced Stirling conversion system project for 25 kW dish Stirling applications

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.; Wong, Wayne A.

    1992-01-01

    Technology development for Stirling convertors directed toward a dynamic power source for space applications is examined. The free-piston Stirling engine has the potential for both solar and nuclear space power applications. Two parallel design directions feature a solar receiver/liquid metal heat transport system, and a free-piston Stirling convertor which incorporates a linear alternator to directly provide the electrical output of about 25 kW to a utility grid. The Cummins Engine Company (CEC) free-piston Stirling convertor incorporates a linear alternator along with hydrodynamic gas bearings to provide noncontacting, wear-free support to the pistons. The Stirling Technology Company design incorporates linear alternator technology with flexures that provide noncontacting support while also supplying much of the spring stiffness needed to obtain proper resonance.

  11. Improving Free-Piston Stirling Engine Specific Power

    NASA Technical Reports Server (NTRS)

    Briggs, Maxwell Henry

    2014-01-01

    This work uses analytical methods to demonstrate the potential benefits of optimizing piston and/or displacer motion in a Stirling Engine. Isothermal analysis was used to show the potential benefits of ideal motion in ideal Stirling engines. Nodal analysis is used to show that ideal piston and displacer waveforms are not optimal in real Stirling engines. Constrained optimization was used to identify piston and displacer waveforms that increase Stirling engine specific power.

  12. Improving Free-Piston Stirling Engine Specific Power

    NASA Technical Reports Server (NTRS)

    Briggs, Maxwell H.

    2015-01-01

    This work uses analytical methods to demonstrate the potential benefits of optimizing piston and/or displacer motion in a Stirling engine. Isothermal analysis was used to show the potential benefits of ideal motion in ideal Stirling engines. Nodal analysis is used to show that ideal piston and displacer waveforms are not optimal in real Stirling engines. Constrained optimization was used to identify piston and displacer waveforms that increase Stirling engine specific power.

  13. Numerical analysis of Stirling engine

    NASA Astrophysics Data System (ADS)

    Sekiya, Hiroshi

    1992-11-01

    A simulation model of the Stirling engine based on the third order method of analysis is presented. The fundamental equations are derived by applying conservation laws of physics to the machine model, the characteristic equations for heat transfer and gas flow are represented, and a numerical calculation technique using these equations is discussed. A numerical model of the system for balancing pressure in four cylinders is included in the simulation model. Calculations results from the model are compared with experimental results. A comparable study of engine performance using helium and hydrogen as working gas is conducted, clarifying the heat transfer and gas flow characteristics, and the effects of temperature conditions in the hot and cold engine sections on driving conditions. The design optimization of the heat exchanger is addressed.

  14. Stirling engine with pressurized crankcase

    SciTech Connect

    Corey, J.A.

    1988-08-23

    This patent describes a Stirling cycle engine comprising an engine housing which includes compression and expansion cylinders and a crankcase area; a compression piston and an expansion piston positioned in respective cylinders in the housing and coupled to a common crankshaft via bearing means. The crankshaft being positioned in the crankcase area which is defined by the pistons and the housing. The pistons includes pad means between the pistons and their respective cylinders to minimize the friction therebetween during reciprocal movement thereof; the crankcase being pressurized to inhibit the passing of working gas past the pistons; and means for cooling the crankshaft and the bearing means eliminating the need for oil in the crankcase.

  15. Ferroelectric Stirling-Cycle Refrigerator

    NASA Technical Reports Server (NTRS)

    Jalink, Antony, Jr. (Inventor); Hellbaum, Richard F. (Inventor); Rohrbach, Wayne W. (Inventor)

    1999-01-01

    A Stirling-cycle refrigerator has a three-pump configuration and pumping sequence, in which one pump serves as a compressor. one pump serves as an expander, and one pump serves as a displacer. The pumps are ferroelectrically actuated diaphragm pumps which are coordinated by synchronizing the ferroelectric-actuator voltages in such a way that the net effect of the displacer is to reduce the deleterious effect of dead space; that is, to circulate a greater fraction of the working fluid through the heat exchangers than would be possible by use of the compressor and expander alone. In addition. the displacer can be controlled separately to make the flow of working fluid in the heat exchangers turbulent (to increase the rate of transfer of heat at the cost of greater resistance to flow) or laminar (to decrease the resistance to flow at the cost of a lower heat-transfer rate).

  16. Self-pressurizing Stirling engine

    DOEpatents

    Bennett, Charles L.

    2010-10-12

    A solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  17. Stirling Engine Dynamic System Modeling

    NASA Technical Reports Server (NTRS)

    Nakis, Christopher G.

    2004-01-01

    The Thermo-Mechanical systems branch at the Glenn Research Center focuses a large amount time on Stirling engines. These engines will be used on missions where solar power is inefficient, especially in deep space. I work with Tim Regan and Ed Lewandowski who are currently developing and validating a mathematical model for the Stirling engines. This model incorporates all aspects of the system including, mechanical, electrical and thermodynamic components. Modeling is done through Simplorer, a program capable of running simulations of the model. Once created and then proven to be accurate, a model is used for developing new ideas for engine design. My largest specific project involves varying key parameters in the model and quantifying the results. This can all be done relatively trouble-free with the help of Simplorer. Once the model is complete, Simplorer will do all the necessary calculations. The more complicated part of this project is determining which parameters to vary. Finding key parameters depends on the potential for a value to be independently altered in the design. For example, a change in one dimension may lead to a proportional change to the rest of the model, and no real progress is made. Also, the ability for a changed value to have a substantial impact on the outputs of the system is important. Results will be condensed into graphs and tables with the purpose of better communication and understanding of the data. With the changing of these parameters, a more optimal design can be created without having to purchase or build any models. Also, hours and hours of results can be simulated in minutes. In the long run, using mathematical models can save time and money. Along with this project, I have many other smaller assignments throughout the summer. My main goal is to assist in the processes of model development, validation and testing.

  18. Design, Analysis, and Optimization of a Radioisotope Thermophotovoltaic (RTPV) Generator, and its Applicability to an Illustrative Space Mission

    SciTech Connect

    Schock, Alfred; Mukunda, Meera; Or, Chuen T; Kumar, Vasanth; Summers, G.

    1994-10-01

    Paper presented at the 45th Congress of the IAF in Jerusalem, Israel, October 1994. The paper describes the results of a DOE-sponsored design study of a radioisotope thermophotovoltaic generator (RTPV), to complement similar studies of Radioisotope Thermoelectric Generators (RTGs) and Stirling Generators (RSGs) previously published by the authors. To focus the design effort, it was decided to direct it at a specific illustrative space mission, Pluto Fast Flyby (PFF). That mission, under study by the JPL, envisages a direct eight to nine-year flight to Pluto (the only unexplored planet in the solar system), followed by comprehensive mapping, surface composition, and atmospheric structure measurements during a brief flyby of the planet and its moon Charon, and transmission of the recorded science data to Earth during a six-week post-encounter cruise.

  19. Automotive Stirling Engine Mod I design review report. Volume III

    SciTech Connect

    Not Available

    1982-08-01

    This volume, No. 3, of the Automotive Stirling Engine Mod 1 Design Review Report contains a preliminary parts list and detailed drawings of equipment for the basic Stirling engine and for the following systems: vehicular Stirling Engine System; external heat system; hot and cold engine systems; engine drive; controls and auxiliaries; and vehicle integration. (LCL)

  20. HFIR-produced medical radioisotopes

    SciTech Connect

    Mirzadeh, S.; Knapp, F.F. Jr.; Beets, A.L.; Alexander, C.W.

    1997-12-01

    We have experimentally determined the yields of a number of medical radioisotopes produced in the Oak Ridge National Laboratory High Flux Isotope Reactor (HFIR) Hydraulic Tube (HT) facility. The HT facility is located in the very high flux region in the flux trap of the reactor, providing on-line access capability while the reactor is operating. The HT facility consists of nine vertically stacked capsules centered just adjacent to the core horizontal midplane. HFIR operates at a nominal power level of 85 MW. The capabilities of the HFIR-HT facilities offer increased efficiency, greater availability, and optimization of radioisotope production, and, as a result, the conservation of rare or expensive target isotopes.

  1. Advanced Stirling conversion systems for terrestrial applications

    NASA Technical Reports Server (NTRS)

    Shaltens, R. K.

    1987-01-01

    Under the Department of Energy's (DOE) Solar Thermal Technology Program, Sandia National Laboratories (SNLA) is developing heat engines for terrestrial Solar Distributed Heat Receivers. SNLA has identified the Stirling to be one of the most promising candidates for the terrestrial applications. The free-piston Stirling engine (FPSE) has the potential to meet the DOE goals for both performance and cost. The National Aeronautics and Space Administration (NASA) Lewis Research Center (LeRC) is conducting free-piston Stirling activities which are directed toward a dynamic power source for space applications. Space power system requirements include high efficiency, very long life, high reliability and low vibration. The FPSE has the potential for future high power space conversion systems, either solar or nuclear. Generic free-piston technology is currently being developed by LeRC for DOE/ORNL for use with a residential heat pump under an Interagency Agreement. Since 1983, the SP-100 Program (DOD/NASA/DOE) is developing dynamic power sources for space. Although both applications (heat pump and space power) appear to be quite different, their requirements complement each other. A cooperative Interagency Agreement (IAA) was signed in 1985 with NASA Lewis to provide technical management for an Advanced Stirling Conversion System (ASCS) for SNLA. Conceptual design(s) using a free-piston Stirling (FPSE), and a heat pipe will be discussed. The ASCS will be designed using technology which can reasonably be expected to be available in the 1980's.

  2. Advanced Stirling conversion systems for terrestrial applications

    SciTech Connect

    Shaltens, R.K.

    1987-01-01

    Sandia National Laboratories (SNLA) is developing heat engines for terrestrial Solar distributed Heat Receivers. SNLA has identified the Stirling to be one of the most promising candidates for the terrestrial applications. The free-piston Stirling engine (FPSE) has the potential to meet the DOE goals for both performance and cost. Free-piston Stirling activities which are directed toward a dynamic power source for the space application are being conducted. Space power system requirements include high efficiency, very long life, high reliability and low vibration. The FPSE has the potential for future high power space conversion systems, either solar or nuclear powered. Generic free-piston technology is currently being developed for use with a residential heat pump under an Interagency Agreement. Also, an overview is presented of proposed conceptual designs for the Advanced Stirling Conversion System (ASCS) using a free-piston Stirling engine and a liquid metal heat pipe receiver. Power extraction includes both a linear alternator and hydraulic output capable of delivering approximately 25 kW of electrical power to the electric utility grid. Target cost of the engine/alternator is 300 dollars per kilowatt at a manufacturing rate of 10,000 units per year. The design life of the ASCS is 60,000 h (30 y) with an engine overhaul at 40,000 h (20 y). Also discussed are the key features and characteristics of the ASCS conceptual designs.

  3. Dynamic Capability of an Operating Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Goodnight, Thomas W.; Hughes, William O.; McNelis, Mark E.

    2000-01-01

    The NASA John H. Glenn Research Center and the US Department of Energy are currently developing a Stirling convertor for use as an advanced spacecraft power system for future NASA deep-space missions. NASA Headquarters has recently identified the Stirling technology generator for potential use as the spacecraft power system for two of NASA's new missions, the Europa Orbiter and the Solar Probe missions (planned for launch in 2006 and 2007 respectively). As part of the development of this power system, a Stirling Technology Demonstration Convertor was vibration tested at NASA John H. Glenn Research Center to verify its survivability and capability of withstanding the harsh dynamic environment typically seen by the spacecraft when it is launched by an expendable launch vehicle. The Technology Demonstration Convertor was fully operational (producing power) during the random vibration testing. The output power of the convertor and other convertor performance indicators were measured during the testing, and these results are discussed in this paper. Numerous accelerometers and force gauges also were used to provide information on the dynamic characteristics of the Technology Demonstration Convertor and as an indication of any possible damage due to the vibration. These measurements will also be discussed in this paper. The vibration testing of the Stirling Technology Demonstration Convertor was extremely successful. The Technology Demonstration Convertor survived all its vibration testing with no structural damage or functional performance degradation. As a result of this testing, the Stirling convertor's capability to withstand vibration has been demonstrated, enabling its usage in future spacecraft power systems.

  4. Ceramic applications in the advanced Stirling automotive engine

    NASA Technical Reports Server (NTRS)

    Tomazic, W. A.; Cairelli, J. E.

    1977-01-01

    The ideal cycle, its application to a practical machine, and the specific advantages of high efficiency, low emissions, multi-fuel capability, and low noise of the stirling engine are discussed. Certain portions of the Stirling engine must operate continuously at high temperature. Ceramics offer the potential of cost reduction and efficiency improvement for advanced engine applications. Potential applications for ceramics in Stirling engines, and some of the special problems pertinent to using ceramics in the Stirling engine are described. The research and technology program in ceramics which is planned to support the development of advanced Stirling engines is outlined.

  5. Alternative fuel capabilities of the Mod II Stirling vehicle

    SciTech Connect

    Grandin, A.W.; Ernst, W.D.

    1988-01-01

    The Stirling engine's characteristics make it a prime candidate for both multifuel and alternative fuel uses. In this paper, the relevant engine characteristics of the Mod II Stirling engine are examined, including the external heat system and basic operation. Adaptation of the Stirling to multifuel operation is addressed, and its experience with alternative fuels in automotive applications is summarized. The results of the U.S. Air Force review of the Stirling's multifuel capability are described, and the Stirling's advantages with liquid, gaseous, and solid fuels are discussed.

  6. Status of the advanced Stirling conversion system project for 25 kW dish Stirling applications

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1991-01-01

    Heat engines were evaluated for terrestrial Solar Distributed Heat Receivers. The Stirling engine was identified as one of the most promising heat engines for terrestrial applications. Technology development is also conducted for Stirling convertors directed toward a dynamic power source for space applications. Space power requirements include high reliability with very long life, low vibration, and high system efficiency. The free-piston Stirling engine has the potential for future high power space conversion systems, either nuclear or solar powered. Although both applications appear to be quite different, their requirements complement each other.

  7. Development of a Phasor Diagram Creator to Visualize the Piston and Displacer Forces in an Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Saha, Dipanjan; Lewandowski, Edward J.

    2013-01-01

    The steady-state, nearly sinusoidal behavior of the components in a free-piston Stirling engine allows for visualization of the forces in the system using phasor diagrams. Based on Newton's second law, F = ma, any phasor diagrams modeling a given component in a system should close if all of the acting forces have been considered. Since the Advanced Stirling Radioisotope Generator (ASRG), currently being developed for future NASA deep space missions, is made up of such nearly sinusoidally oscillating components, its phasor diagrams would also be expected to close. A graphical user interface (GUI) has been written in MATLAB (MathWorks), which takes user input data, passes it to Sage (Gedeon Associates), a one-dimensional thermodynamic modeling program used to model the Stirling convertor, runs Sage, and then automatically plots the phasor diagrams. Using this software tool, the effect of varying different Sage inputs on the phasor diagrams was determined. The parameters varied were piston amplitude, hot-end temperature, cold-end temperature, operating frequency, and displacer spring constant. These phasor diagrams offer useful insight into convertor operation and performance.

  8. Development of a Phasor Diagram Creator to Visualize the Piston and Displacer Forces in an Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Saha, Dipanjan; Lewandowski, Edward J.

    2013-01-01

    The steady state, nearly sinusoidal behavior of the components in a Free Piston Stirling Engine allows for visualization of the forces in the system using phasor diagrams. Based on Newton's second law, F=ma, any phasor diagrams modeling a given component in a system should close if all of the acting forces have been considered. Since the Advanced Stirling Radioisotope Generator (ASRG), currently being developed for future NASA deep space missions, is made up of such nearly sinusoidally oscillating components, its phasor diagrams would also be expected to close. A graphical user interface (GUI) has been written in MATLAB by taking user input data, passing it to Sage, a 1-D thermodynamic modeling program used to model the Stirling convertor, running Sage and then automatically plotting the phasor diagrams. Using this software tool, the effect of varying different Sage inputs on the phasor diagrams was determined. The parameters varied were piston amplitude, hot end temperature, cold end temperature, operating frequency, and displacer spring constant. By using these phasor diagrams, better insight can be gained as to why the convertor operates the way that it does.

  9. A compendium of solar dish/Stirling technology

    SciTech Connect

    Stine, W.B.; Diver, R.B.

    1994-01-01

    This report surveys the emerging dish/Stirling technology. It documents -- using consistent terminology the design characteristics of dish concentrators, receivers, and Stirling engines applicable to solar electric power generation. Development status and operating experience for each system and an overview of dish/Stirling technology are also presented. This report enables comparisons of concentrator, receiver, and engine technologies. Specifications and performance data are presented on systems and on components that are in use or that could be used in dish/Stirling systems. This report is organized into two parts: The first part (Chapters 1 through 4) provides an overview of dish/Stirling technology -- the dish/ Stirling components (concentrator, receiver, and engine/alternator), current technology, basic theory, and technology development. The second part (Chapters 5 through 7) provides a detailed survey of the existing dish/Stirling concentrators, receivers, and engine/alternators.

  10. Benchmark Calibration Tests Completed for Stirling Convertor Heater Head Life Assessment

    NASA Technical Reports Server (NTRS)

    Krause, David L.; Halford, Gary R.; Bowman, Randy R.

    2005-01-01

    A major phase of benchmark testing has been completed at the NASA Glenn Research Center (http://www.nasa.gov/glenn/), where a critical component of the Stirling Radioisotope Generator (SRG) is undergoing extensive experimentation to aid the development of an analytical life-prediction methodology. Two special-purpose test rigs subjected SRG heater-head pressure-vessel test articles to accelerated creep conditions, using the standard design temperatures to stay within the wall material s operating creep-response regime, but increasing wall stresses up to 7 times over the design point. This resulted in well-controlled "ballooning" of the heater-head hot end. The test plan was developed to provide critical input to analytical parameters in a reasonable period of time.

  11. Component technology for Stirling power converters

    SciTech Connect

    Thieme, L.G.

    1994-09-01

    NASA Lewis Research Center has organized a component technology program as part of the efforts to develop Stirling converter technology for space power applications. The Stirling space power program is part of the NASA High Capacity Power Project of the Civil Space Technology Initiative (CSTI). NASA Lewis is also providing technical management for a DOE/Sandia program to develop Stirling converters for solar terrestrial power producing electricity for the utility grid. The primary contractors for the space power and solar terrestrial programs develop component technologies directly related to their program goals. This Lewis component technology effort, while coordinated with the main programs, aims at longer term issues, advanced technologies, and independent assessments. This paper will present an overview of work on linear alternators, engine/alternator/load interactions and controls, heat exchangers, materials, life and reliability, and bearings.

  12. A new, versatile Stirling energy conversion unit

    SciTech Connect

    Meijer, R.J.; Ziph, B.

    1982-08-01

    A new concept in Stirling engine technology is embodied in the ''Base Engine'' now being developed at Stirling Thermal Motors, Inc. This is a versatile energy conversion unit suitable for many different applications and heat sources. The Base Engine, rated at 40 kw at 2800 rpm, is a four cylinder, double acting, variable displacement Stirling engine. It incorporates remote-heating technology with a stacked-heat-exchanger configuration and a liquid metal heat pipe connected to a distinctly separate combustor or other heat source. It specifically emphasizes high efficiency over a wide range of operating conditions, long life, low manufacturing cost and low material cost. This paper describes the Base Engine, its design philosophy and approach, its projected performance, and some of its more attractive applications.

  13. Hermetic metal seals for Stirling engines

    SciTech Connect

    White, M.A.; Emigh, S.G.; Gray, D.M.; Krogness, J.C.; Noble, J.E.; Olam, R.W.; Oster, J.F.; Riggle, P.

    1984-08-01

    Dynamic seals continue to be one of the major technical problems facing Stirling engine designers. Much effort has been expended to develop the quasi-hermetic rolling diaphragm or rollsock seal, but unpredictable lifetime has resulted in general disuse of this once promising seal. Most modern engines use some version of the Leningrader sliding seal for rod seals and a dry ring seal for piston and/or displacer seals. Reliable long-life seals remain an elusive goal. This paper documents the successful hardware implementation of metal bellows and diaphragm seals in two long-life Stirling engine applications with test data to >10/sup 10/ cycles and discusses bellows seal concepts which can provide reliable and efficient longlife seals for virtually any Stirling engine application.

  14. Base engine for solar Stirling power

    SciTech Connect

    Meijer, R.J.; Godett, T.M.

    1984-03-01

    A new concept in Stirling engine technology is embodied in the base engine now being developed at Stirling Thermal Motors, Inc. This is a versatile energy conversion unit suitable for many different applications and heat sources. The base engine, rated 40 kW at 2800 RPM, is a four-cylinder, double-acting variable displacement Stirling engine with pressurized crankcase and rotating shaft seal. Remote-heating technology is incorporated with a stacked-heat-exchanger configuration and a liquid metal heat pipe connected to a distinctly separate combustor or other heat source. High efficiency over a wide range of operating conditions, long life, low manufacturing cost and low material cost are specifically emphasized. The base engine, its design philosophy and approach, its projected performance, and some of its more attractive applications are described.

  15. Fast Whole-Engine Stirling Analysis

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger W.; Wilson, Scott D.; Tew, Roy C.; Demko, Rikako

    2005-01-01

    An experimentally validated approach is described for fast axisymmetric Stirling engine simulations. These simulations include the entire displacer interior and demonstrate it is possible to model a complete engine cycle in less than an hour. The focus of this effort was to demonstrate it is possible to produce useful Stirling engine performance results in a time-frame short enough to impact design decisions. The combination of utilizing the latest 64-bit Opteron computer processors, fiber-optical Myrinet communications, dynamic meshing, and across zone partitioning has enabled solution times at least 240 times faster than previous attempts at simulating the axisymmetric Stirling engine. A comparison of the multidimensional results, calibrated one-dimensional results, and known experimental results is shown. This preliminary comparison demonstrates that axisymmetric simulations can be very accurate, but more work remains to improve the simulations through such means as modifying the thermal equilibrium regenerator models, adding fluid-structure interactions, including radiation effects, and incorporating mechanodynamics.

  16. Cost estimating Brayton and Stirling engines

    NASA Technical Reports Server (NTRS)

    Fortgang, H. R.

    1980-01-01

    Brayton and Stirling engines were analyzed for cost and selling price for production quantities ranging from 1000 to 400,000 units per year. Parts and components were subjected to indepth scrutiny to determine optimum manufacturing processes coupled with make or buy decisions on materials and small parts. Tooling and capital equipment costs were estimated for each detail and/or assembly. For low annual production volumes, the Brayton engine appears to have a lower cost and selling price than the Stirling Engine. As annual production quantities increase, the Stirling becomes a lower cost engine than the Brayton. Both engines could benefit cost wise if changes were made in materials, design and manufacturing process as annual production quantities increase.

  17. The Base Engine for Solar Stirling Power

    NASA Technical Reports Server (NTRS)

    Meijer, R. J.; Godett, T. M.

    1984-01-01

    A new concept in Stirling engine technology is embodied in the base engine now being developed at Stirling Thermal Motors, Inc. This is a versatile energy conversion unit suitable for many different applications and heat sources. The base engine, rated 40 kW at 2800 RPM, is a four-cylinder, double-acting variable displacement Stirling engine with pressurized crankcase and rotating shaft seal. Remote-heating technology is incorporated with a stacked-heat-exchanger configuration and a liquid metal heat pipe connected to a distinctly separate combustor or other heat source. High efficiency over a wide range of operating conditions, long life, low manufacturing cost and low material cost are specifically emphasized. The base engine, its design philosophy and approach, its projected performance, and some of its more attractive applications are described.

  18. A model regenerator for a Stirling cycle

    NASA Astrophysics Data System (ADS)

    Carolan, James

    2001-05-01

    An essential feature of the engine patented by Robert Stirling in 1817 was the careful description of the idea of regeneration. In the standard thermodynamic cycle representation of the engine, regeneration is the storing and the reusing of the thermal energy released in the constant volume cooling part of the cycle. Due to the difficulty in treating regeneration quantitatively, introductory physics texts generally either ignore the concept or assume the regeneration to be perfect. As a result students obtain little or no understanding of regeneration. In addition there seem to be differing views in various texts about the efficiency of Stirling engines. In this work a simple finite element model regenerator is presented with which one can do simple calculations. The model does not accurately represent actual regeneration in a practical engine. But the model might help students gain better insight into Stirling engine efficiency and the idea of regeneration.

  19. Fast Whole-Engine Stirling Analysis

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger W.; Wilson, Scott D.; Tew, Roy C.; Demko, Rikako

    2007-01-01

    An experimentally validated approach is described for fast axisymmetric Stirling engine simulations. These simulations include the entire displacer interior and demonstrate it is possible to model a complete engine cycle in less than an hour. The focus of this effort was to demonstrate it is possible to produce useful Stirling engine performance results in a time-frame short enough to impact design decisions. The combination of utilizing the latest 64-bit Opteron computer processors, fiber-optical Myrinet communications, dynamic meshing, and across zone partitioning has enabled solution times at least 240 times faster than previous attempts at simulating the axisymmetric Stirling engine. A comparison of the multidimensional results, calibrated one-dimensional results, and known experimental results is shown. This preliminary comparison demonstrates that axisymmetric simulations can be very accurate, but more work remains to improve the simulations through such means as modifying the thermal equilibrium regenerator models, adding fluid-structure interactions, including radiation effects, and incorporating mechanodynamics.

  20. Component technology for stirling power converters

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.

    1991-01-01

    NASA Lewis Research Center has organized a component technology program as part of the efforts to develop Stirling converter technology for space power applications. The Stirling Space Power Program is part of the NASA High Capacity Power Project of the Civil Space Technology Initiative (CSTI). NASA Lewis is also providing technical management for the DOE/Sandia program to develop Stirling converters for solar terrestrial power producing electricity for the utility grid. The primary contractors for the space power and solar terrestrial programs develop component technologies directly related to their goals. This Lewis component technology effort, while coordinated with the main programs, aims at longer term issues, advanced technologies, and independent assessments. An overview of work on linear alternators, engine/alternator/load interactions and controls, heat exchangers, materials, life and reliability, and bearings is presented.

  1. Component technology for Stirling power converters

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.

    1991-01-01

    NASA Lewis Research Center has organized a component technology program as part of the efforts to develop Stirling converter technology for space power applications. The Stirling Space Power Program is part of the NASA High Capacity Power Project of the Civil Space Technology Initiative (CSTI). NASA Lewis is also providing technical management for the DOE/Sandia program to develop Stirling converters for solar terrestrial power producing electricity for the utility grid. The primary contractors for the space power and solar terrestrial programs develop component technologies directly related to their goals. This Lewis component technology effort, while coordinated with the main programs, aims at longer term issues, advanced technologies, and independent assessments. An overview of work on linear alternators, engine/alternator/load interactions and controls, heat exchangers, materials, life and reliability, and bearings is presented.

  2. Component technology for Stirling power converters

    NASA Astrophysics Data System (ADS)

    Thieme, Lanny G.

    NASA Lewis Research Center has organized a component technology program as part of the efforts to develop Stirling converter technology for space power applications. The Stirling Space Power Program is part of the NASA High Capacity Power Project of the Civil Space Technology Initiative (CSTI). NASA Lewis is also providing technical management for the DOE/Sandia program to develop Stirling converters for solar terrestrial power producing electricity for the utility grid. The primary contractors for the space power and solar terrestrial programs develop component technologies directly related to their goals. This Lewis component technology effort, while coordinated with the main programs, aims at longer term issues, advanced technologies, and independent assessments. An overview of work on linear alternators, engine/alternator/load interactions and controls, heat exchangers, materials, life and reliability, and bearings is presented.

  3. List of DOE radioisotope customers with summary of radioisotope shipments, FY 1985

    SciTech Connect

    Baker, D.A.

    1986-08-01

    This document describes radioisotope distribution from DOE facilities to private firms including foreign and other DOE facilities. The information is divided into five sections: (1) isotope suppliers, facility contacts, and isotopes or services supplied; (2) customers, suppliers, and isotopes purchased; (3) isotopes purchased cross-referenced with customer numbers; (4) geographic locations of radioisotope customers; and (5) radioisotope sales and transfer - FY 1985.

  4. A liquid xenon radioisotope camera.

    NASA Technical Reports Server (NTRS)

    Zaklad, H.; Derenzo, S. E.; Muller, R. A.; Smadja, G.; Smits, R. G.; Alvarez, L. W.

    1972-01-01

    A new type of gamma-ray camera is discussed that makes use of electron avalanches in liquid xenon and is currently under development. It is shown that such a radioisotope camera promises many advantages over any other existing gamma-ray cameras. Spatial resolution better than 1 mm and counting rates higher than one million C/sec are possible. An energy resolution of 11% FWHM has recently been achieved with a collimated Hg-203 source using a parallel-plate ionization chamber containing a Frisch grid.

  5. Pathfinding the Flight Advanced Stirling Convertor Design with the ASC-E3

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Wilson, Kyle; Smith, Eddie; Collins, Josh

    2012-01-01

    The Advanced Stirling Convertor (ASC) was initially developed by Sunpower, Inc. under contract to NASA Glenn Research Center (GRC) as a technology development project. The ASC technology fulfills NASA s need for high efficiency power convertors for future Radioisotope Power Systems (RPS). Early successful technology demonstrations between 2003 to 2005 eventually led to the expansion of the project including the decision in 2006 to use the ASC technology on the Advanced Stirling Radioisotope Generator (ASRG). Sunpower has delivered 22 ASC convertors of progressively mature designs to date to GRC. Currently, Sunpower with support from GRC, Lockheed Martin Space System Company (LMSSC), and the Department of Energy (DOE) is developing the flight ASC-F in parallel with the ASC-E3 pathfinders. Sunpower will deliver four pairs of ASC-E3 convertors to GRC which will be used for extended operation reliability assessment, independent validation and verification testing, system interaction tests, and to support LMSSC controller verification. The ASC-E3 and -F convertors are being built to the same design and processing documentation and the same product specification. The initial two pairs of ASC-E3 are built before the flight units and will validate design and processing changes prior to implementation on the ASC-F flight convertors. This paper provides a summary on development of the ASC technology and the status of the ASC-E3 build and how they serve the vital pathfinder role ahead of the flight build for ASRG. The ASRG is part of two of the three candidate missions being considered for selection for the Discovery 12 mission.

  6. SRG110 Stirling Generator Dynamic Simulator Vibration Test Results and Analysis Correlation

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Suarez, Vicente J.; Goodnight, Thomas W.; Callahan, John

    2007-01-01

    The U.S. Department of Energy (DOE), Lockheed Martin (LM), and NASA Glenn Research Center (GRC) have been developing the Stirling Radioisotope Generator (SRG110) for use as a power system for space science missions. The launch environment enveloping potential missions results in a random input spectrum that is significantly higher than historical radioisotope power system (RPS) launch levels and is a challenge for designers. Analysis presented in prior work predicted that tailoring the compliance at the generator-spacecraft interface reduced the dynamic response of the system thereby allowing higher launch load input levels and expanding the range of potential generator missions. To confirm analytical predictions, a dynamic simulator representing the generator structure, Stirling convertors and heat sources were designed and built for testing with and without a compliant interface. Finite element analysis was performed to guide the generator simulator and compliant interface design so that test modes and frequencies were representative of the SRG110 generator. This paper presents the dynamic simulator design, the test setup and methodology, test article modes and frequencies and dynamic responses, and post-test analysis results. With the compliant interface, component responses to an input environment exceeding the SRG110 qualification level spectrum were all within design allowables. Post-test analysis included finite element model tuning to match test frequencies and random response analysis using the test input spectrum. Analytical results were in good overall agreement with the test results and confirmed previous predictions that the SRG110 power system may be considered for a broad range of potential missions, including those with demanding launch environments.

  7. Pathfinding the Flight Advanced Stirling Convertor Design with the ASC-E3

    NASA Technical Reports Server (NTRS)

    Wong, Wayne A.; Wilson, Kyle; Smith, Eddie; Collins, Josh

    2012-01-01

    The Advanced Stirling Convertor (ASC) was initially developed by Sunpower, Inc. under contract to NASA Glenn Research Center (GRC) as a technology development project. The ASC technology fulfills NASA's need for high efficiency power convertors for future Radioisotope Power Systems (RPS). Early successful technology demonstrations between 2003 to 2005 eventually led to the expansion of the project including the decision in 2006 to use the ASC technology on the Advanced Stirling Radioisotope Generator (ASRG). Sunpower has delivered 22 ASC convertors of progressively mature designs to date to GRC. Currently, Sunpower with support from GRC, Lockheed Martin Space System Company (LMSSC), and the Department of Energy (DOE) is developing the flight ASC-F in parallel with the ASC-E3 pathfinders. Sunpower will deliver four pairs of ASC-E3 convertors to GRC which will be used for extended operation reliability assessment, independent validation and verification testing, system interaction tests, and to support LMSSC controller verification. The ASC-E3 and -F convertors are being built to the same design and processing documentation and the same product specification. The initial two pairs of ASC-E3 are built before the flight units and will validate design and processing changes prior to implementation on the ASC-F flight convertors. This paper provides a summary on development of the ASC technology and the status of the ASC-E3 build and how they serve the vital pathfinder role ahead of the flight build for ASRG. The ASRG is part of two of the three candidate missions being considered for selection for the Discovery 12 mission.

  8. HTC solar Stirling development Sunset Powerstation

    SciTech Connect

    Mitzel, M.; Leibfried, I.U.

    1995-11-01

    The components of a new dish-Stirling system are presented. Special emphasis on the system design is given to realize a simple and highly reliable system for applications in a low technology context. The development of the new double chamber stretched-membrane dish is described, including the investigation of a secondary concentrator. The data of the TEM SCP-75 Stirling engine is given. A new copper mantled heater head for utilizing solar power is presented. Performance data for the whole system is reported.

  9. Analysis of an idealized Stirling thermocompressor

    SciTech Connect

    Kornhauser, A.A.

    1996-12-31

    A thermocompressor uses thermal energy to increase the pressure of a fluid without the intermediate production of mechanical work. The thermocompressor described here is essentially a cold-connected Gamma Stirling engine with the power cylinder replaced by inlet and discharge check valves. It is analyzed based on assumptions similar to those made in the analysis of an ideal Stirling engine. The analysis gives closed form predictions for thermocompressor thermal efficiency, volumetric efficiency, and non-dimensional heat input as functions of pressure and temperature ratio. It is also used to compare thermocompressor performance to that of an ideal Otto engine-driven mechanical compressor.

  10. Phase-angle controller for Stirling engines

    SciTech Connect

    Frosch, R.A.; McDougal, A.R.

    1980-12-23

    A first embodiment incorporating an actuator including a restraint link adapted to be connected with a pivotal carrier arm for a force transfer gear interposed between the crankshaft for an expander portion of a stirling engine and a crankshaft for the displacer portion of the engine is described. The restraint link is releasably supported against axial displacement by releasably trapped hydraulic fluid for selectively establishing a phase angle relationship between the crankshaft and a second embodiment incorporating a hydraulic coupler for use in varying the phase angle of gear-coupled crankshafts for a Stirling engine whereby phase angle changes are obtainable.

  11. Phase-angle controller for Stirling engines

    NASA Technical Reports Server (NTRS)

    Mcdougal, A. R. (Inventor)

    1980-01-01

    An actuator includes a restraint link adapted to be connected with a pivotal carrier arm for a force transfer gear interposed between the crankshaft for an expander portion of a Stirling engine and a crankshaft for the displacer portion of the engine. The restraint link is releasably trapped hydraulic fluid for selectively establishing a phase angle relationship between the crankshaft. A second embodiment incorporates a hydraulic coupler for use in varying the phase angle of gear-coupled crank fpr a Stirling engine whereby phase angle changes are obtainable.

  12. Two piston V-type Stirling engine

    SciTech Connect

    Corey, J.A.

    1987-01-06

    This patent describes a Stirling cycle engine comprising: a compression piston reciprocal in a cold compression space and an expansion piston operated from a common crank shaft reciprocal in an expansion space out of phase with respect to each other. The pistons reciprocate along axes which are angularly disposed to one another, such that a V-configuration engine is formed. A regenerator means is positioned immediately adjacent a cooling means. The cooling means is axially aligned immediately adjacent the cold compression piston so as to minimize cold duct volume. A heating means is coupled with the regenerator and the expansion space completing the Stirling cycle.

  13. Heat exchanger for a Stirling engine

    SciTech Connect

    Fujiwara, M.; Nomaguchi, T.; Kazumoto, Y.; Tsuchino, K.; Kawajiri, K.; Hisamori, Y.

    1987-05-05

    A heat exchanger is described for a Stirling engine comprising: a domed cylinder having a domed portion and a cylindrical portion. The domed cylinder serves as a high-temperature cylinder and a regenerator housing of the Stirling engine; a cylindrical inner liner which is coaxially disposed inside the domed cylinder and which divides the inside of the domed cylinder into an expansion space inside of the inner liner and a regenerator space between the outer surface of the inner liner and the inner surface of the cylindrical portion of the domed cylinder.

  14. Identification of a Stirling engine's torque characteristics

    SciTech Connect

    Reader, G.T.; Hooper, C.; Taylor, D.R.

    1983-08-01

    The Stirling engine has many advantages claimed for it when compared to other reciprocating heat engines, one of these claimed advantages being the so-called 'smooth torque' characteristic. On further investigation of this virtue it was found that no definitive description of 'smooth torque' existed. With the expansion in recent years of the quantity of Stirling Engine test data it is apparent that some means of obtaining a numerical value for the smoothness of a torque is required. This paper defines a coefficient which enables the smoothness of a torque output to be measured in a definitive way so that comparisons can be made objectively.

  15. Enhanced design for a miniature Stirling machine

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboro; Araoka, Katsumasa; Otaka, Toshio

    A small size engine, SD01 has been developed since 1989. For the purpose of cultivating the advantageous properties of the SD01 engine, its cylindrical cam mechanism was modified. The modification was able to operate the Stirling cycle stably and silently. The modified SD01 coupled with an electric motor was reconstructed as a hermetic cooler. The attractive Stirling cooler was evaluated on the conditions of a cooling mode. Moreover, with an aid of the enhanced design concept for the SD01 machine, a small size Vuilleumier machine for heat pump applications was designed and constructed.

  16. System safety in Stirling engine development

    NASA Technical Reports Server (NTRS)

    Bankaitis, H.

    1981-01-01

    The DOE/NASA Stirling Engine Project Office has required that contractors make safety considerations an integral part of all phases of the Stirling engine development program. As an integral part of each engine design subtask, analyses are evolved to determine possible modes of failure. The accepted system safety analysis techniques (Fault Tree, FMEA, Hazards Analysis, etc.) are applied in various degrees of extent at the system, subsystem and component levels. The primary objectives are to identify critical failure areas, to enable removal of susceptibility to such failures or their effects from the system and to minimize risk.

  17. Stirling laboratory research engine survey report

    NASA Technical Reports Server (NTRS)

    Anderson, J. W.; Hoehn, F. W.

    1979-01-01

    As one step in expanding the knowledge relative to and accelerating the development of Stirling engines, NASA, through the Jet Propulsion Laboratory (JPL), is sponsoring a program which will lead to a versatile Stirling Laboratory Research Engine (SLRE). An objective of this program is to lay the groundwork for a commercial version of this engine. It is important to consider, at an early stage in the engine's development, the needs of the potential users so that the SLRE can support the requirements of educators and researchers in academic, industrial, and government laboratories. For this reason, a survey was performed, the results of which are described.

  18. COMPASS Final Report: Radioisotope Electric Propulsion (REP) Centaur Orbiter New Frontiers Mission

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; McGuire, Melissa L.

    2011-01-01

    Radioisotope Electric Propulsion (REP) has been shown in past studies to enable missions to outer planetary bodies including the orbiting of Centaur asteroids. Key to the feasibility for REP missions are long life, low power electric propulsion (EP) devices, low mass Radioisotope Power System (RPS) and light spacecraft (S/C) components. In order to determine the key parameters for EP devices to perform these REP missions a design study was completed to design an REP S/C to orbit a Centaur in a New Frontiers (NF) cost cap. The design shows that an orbiter using several long lived (approx.200 kg xenon (Xe) throughput), low power (approx.700 W) Hall thrusters teamed with six (150 W each) Advanced Stirling Radioisotope Generators (ASRG) can deliver 60 kg of science instruments to a Centaur in 10 yr within the NF cost cap. Optimal specific impulses (Isp) for the Hall thrusters were found to be around 2000 s with thruster efficiencies over 40 percent. Not only can the REP S/C enable orbiting a Centaur (when compared to an all chemical mission only capable of flybys) but the additional power from the REP system can be used to enhance science and simplify communications. The mission design detailed in this report is a Radioisotope Power System (RPS) powered EP science orbiter to the Centaur Thereus with arrival 10 yr after launch, ending in a 1 yr science mapping mission. Along the trajectory, approximately 1.5 yr into the mission, the REP S/C does a flyby of the Trojan asteroid Tlepolemus. The total (Delta)V of the trajectory is 8.9 km/s. The REP S/C is delivered to orbit on an Atlas 551 class launch vehicle with a Star 48 B solid rocket stage

  19. Automotive Stirling Engine Development Program

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The third quarter (April-June, 1978) effort of the Ford/DOE Automotive Stirling Engine Development Program is reported, specifically Task 1 of that effort, which is Fuel Economy Assessment. At the end of this quarter the total fourth generation fuel economy projection was 26.12 MPG (gasoline) with a confidence level of 44%. This represents an improvement of 66.4% over the baseline M-H fuel economy of 15.7 MPG. The confidence level for the original 20.6 MPG goal has been increased from 53% to 57%. Engine 3X17 has accumulated a total of 213 hours of variable speed running. A summary of the individual sub-tasks of Task 1 are given. The sub-tasks are grouped into two categories: Category 1 consists of those sub-tasks which are directly related to fuel economy and Category 2 consists of those sub-tasks which are not directly related to fuel economy but are an integral part of the Task 1 effort.

  20. Hydrogen Internal Combustion Stirling Engine

    NASA Astrophysics Data System (ADS)

    Takahashi, Sanyo; Morita, Hiroyuki; Kurata, Osamu; Yamashita, Iwao

    The hydrogen combustion Stirling engine utilizes internal combustion of a stoichiometric H2 and O2 mixture injected into the working gas as thermal input, and the cyclic operation is completed with the removal of water from the engine after condensation at the cooler. In the prototype engine, a catalytic combustor is substituted for the conventional heater, and the H2-O2 mixture is injected at a constant flow rate from the boundary between the regenerator and the cooler. The engine internal heating characteristics were compared to those on external heating to clarify the internal heating effect on the engine performance. The internal heating performance showed almost the same characteristics as those of external heating, except for the increase of expansion work due to the direct thermal input. The increase of expansion work improved the engine performance, particularly in the region of high engine speed. Furthermore, it was found that the steady injection method was able to suppress the mixture strength to a relatively low level.

  1. Status of the advanced Stirling conversion system project for 25 kW dish Stirling applications

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1991-01-01

    Technology development for Stirling convertors directed toward a dynamic power source for space applications is discussed. Space power requirements include high reliability with very long life, low vibration, and high system efficiency. The free-piston Stirling engine has the potential for future high power space conversion systems, either nuclear or solar powered. Although these applications appear to be quite different, their requirements complement each other. The advanced Stirling conversion system (ASCS) project at NASA Lewis Research Center is described. Each system design features a solar receiver/liquid metal heat transport system and a free-piston Stirling convertor with a means to provide nominally 25 kW of electric power to utility grid while meeting the US Department of Energy (DOE) performance and long term cost goals. The design is compared with other ASCS designs.

  2. Status of several Stirling loss characterization efforts and their significance for Stirling space power development

    NASA Technical Reports Server (NTRS)

    Tew, Roy C., Jr.

    1988-01-01

    NASA-Lewis and other U.S. Government agencies have supported experimental and analytical programs for the characterization of Stirling cycle engines' thermodynamic losses, with a view to the improvement of Stirling engine design capabilities. The Space Power Demonstrator Engine is noted to have benefited from these efforts; test data and model predictions suggest that even greater performance improvements would be obtainable through additional modifications of engine regenerator and heater hardware.

  3. Status of the Advanced Stirling Conversion System Project for 25 kW dish Stirling applications

    SciTech Connect

    Shaltens, R.K.; Schreiber, J.G.

    1991-01-01

    Under the Department of Energy's (DOE) Solar Thermal Technology Program, Sandia National Laboratories is evaluating heat engines for terrestrial Solar Heat Receivers. The Stirling engine has been identified by Sandia as one of the most promising heat engines for terrestrial applications. The Stirling engine also has the potential to meet DOE's performance and cost goals. The NASA Lewis Research Center is conducting technology development for Stirling convertors directed toward a dynamic power source for space applications. Space power requirements include high reliability with very long life, low vibration and high system efficiency. The free-piston Stirling engine has the potential for future high power space conversion systems, either nuclear or solar powered. Although both applications appear to be quite different, their requirements complement each other. NASA Lewis is providing management of the Advanced Stirling Conversion System (ASCS) Project through an Interagency Agreement (IAA) with the DOE. Parallel contracts continue with both Cummins Engine Company (CEC), Columbus, Indiana, and Stirling Technology Company (STC), Richland, Washington for the designs of an ASCS. Each system'' design features a solar receiver/liquid metal heat transport system, and a free-piston Stirling convertor with a means to provide nominally 25 kW of electric power to a utility grid while meeting DOE's performance and long-term'' cost goals. The Cummins free- piston Stirling convertor incorporates a linear alternator to directly provide the electrical output, while the STC design generates electrical power indirectly through a hydraulic pump/motor coupled to an induction generator. Both the Cummins and STC ASCS designs will use technology which can reasonably be expected to be available in the early 1990's. 17 refs., 7 figs., 3 tabs.

  4. Cosmogenic radioisotopes on LDEF surfaces

    NASA Technical Reports Server (NTRS)

    Gregory, J. C.; Albrecht, A.; Herzog, G.; Klein, J.; Middleton, R.

    1992-01-01

    The radioisotope Be-7 was discovered in early 1990 on the front surface, and the front surface only, of the LDEF. A working hypothesis is that the isotope, which is known to be mainly produced in the stratosphere by spallation of nitrogen and oxygen nuclei with cosmic ray protons or secondary neutrons, diffuses upward and is absorbed onto metal surfaces of spacecraft. The upward transport must be rapid, that is, its characteristic time scale is similar to, or shorter than, the 53 day half-life of the isotope. It is probably by analogy with meteoritic metal atmospheric chemistry, that the form of the Be at a few 100 km altitude is as the positive ion Be(+) which is efficiently incorporated into the ionic lattice of oxides, such as Al2O3, Cr2O3, Fe2O3, etc., naturally occurring on surfaces of Al and stainless steel. Other radioisotopes of Be, Cl, and C are also produced in the atmosphere, and a search was begun to discover these. Of interest are Be-10 and C-14 for which the production cross sections are well known. The method of analysis is accelerator mass spectrometry. Samples from LDEF clamp plates are being chemically extracted, purified, and prepared for an accelerator run.

  5. Radioisotope penogram in diagnosis of vasculogenic impotence

    SciTech Connect

    Fanous, H.N.; Jevtich, M.J.; Chen, D.C.; Edson, M.

    1982-11-01

    A radioisotope technique to estimate penile blood flow is described. The radioisotope penogram is noninvasive and gives a dynamic evaluation of the arterial supply, venous drainage, and blood flow in the corporeal bodies. The penogram is a valuable adjunct in evaluation of patients with vasculogenic impotence.

  6. Power from Radioisotopes, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Corliss, William R.; Mead, Robert L.

    This 1971 revision deals with radioisotopes and their use in power generators. Early developments and applications for the Systems for Nuclear Auxiliary Power (SNAP) and Radioisotope Thermoelectric Generators (RTGs) are reviewed. Present uses in space and on earth are included. Uses in space are as power sources in various satellites and space…

  7. Piston rod seal for a Stirling engine

    SciTech Connect

    Shapiro, W.

    1984-01-31

    In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal. 3 figs.

  8. Stirling engine patents: international patent inventory

    SciTech Connect

    Newman, B.K.

    1983-09-01

    One hundred seventy-five years (1817-1982) of research and development (R and D) in Stirling-cycle engines is represented in this international inventory of patent applications. The following lists are included: assignor, assignee, patent numbers, US patent classification, and international patent classification. (MHR)

  9. Experimental research on the Stirling engine

    NASA Technical Reports Server (NTRS)

    Ishizaki, Y.; Tani, Y.; Haramura, N.

    1982-01-01

    Experiments on Stirling engines of the 50 KW class were conducted to clarify the characteristics of the engine and its problems. The problems involve durability of the high temperature heat exchanger which is exposed to high flame temperatures above 1600 C, thermal distortion and high temperature corrosion of the devices near combustion, and of the preheater.

  10. Materials technology for Stirling space power converters

    NASA Technical Reports Server (NTRS)

    Baggenstoss, William; Mittendorf, Donald

    1992-01-01

    This program was conducted in support of the NASA LeRC development of the Stirling power converter (SPC) for space power applications. The objectives of this contract were: (1) to perform a technology review and analyses to support the evaluation of materials issues for the SPC; (2) to evaluate liquid metal compatibility issues of the SPC; (3) to evaluate and define a transient liquid phase diffusion bonding (TLPDB) process for the SPC joints to the Udimet 720 heater head; and (4) to evaluate alternative (to the TLPDB) joining techniques. In the technology review, several aspects of the current Stirling design were examined including the power converter assembly process, materials joining, gas bearings, and heat exchangers. The supporting analyses included GLIMPS power converter simulation in support of the materials studies, and system level analysis in support of the technology review. The liquid metal compatibility study evaluated process parameters for use in the Stirling power converter. The alternative joining techniques study looked at the applicability of various joining techniques to the Stirling power converter requirements.

  11. Computer program for Stirling engine performance calculations

    NASA Technical Reports Server (NTRS)

    Tew, R. C., Jr.

    1983-01-01

    The thermodynamic characteristics of the Stirling engine were analyzed and modeled on a computer to support its development as a possible alternative to the automobile spark ignition engine. The computer model is documented. The documentation includes a user's manual, symbols list, a test case, comparison of model predictions with test results, and a description of the analytical equations used in the model.

  12. Two piston V-type Stirling engine

    DOEpatents

    Corey, John A.

    1987-01-01

    A two piston Stirling engine which includes a heat exchanger arrangement placing the cooler and regenerator directly adjacent the compression space for minimal cold duct volume; a sealing arrangement which eliminates the need for piston seals, crossheads and piston rods; and a simplified power control system.

  13. The Stirling Lesson-Sampling Instruments.

    ERIC Educational Resources Information Center

    White, D. R.

    A long-term Leverhulme Research Project was established at Stirling University in 1970 to investigate the potential of microteaching as a major ingredient in the preparation of graduate high school teachers in Scotland. Members of the research team developed systematic observation schedules for each of the skills, in order to sharpen the focus of…

  14. Quirks of Stirling's Approximation

    ERIC Educational Resources Information Center

    Macrae, Roderick M.; Allgeier, Benjamin M.

    2013-01-01

    Stirling's approximation to ln "n"! is typically introduced to physical chemistry students as a step in the derivation of the statistical expression for the entropy. However, naive application of this approximation leads to incorrect conclusions. In this article, the problem is first illustrated using a familiar "toy…

  15. Vibration Testing of an Operating Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Mark E.; Goodnight, Thomas W.

    2000-01-01

    The NASA John H. Glenn Research Center and the U.S. Department of Energy are currently developing a Stirling convertor for use as an advanced spacecraft power system for future NASA deep-space missions. As part of this development, a Stirling Technology Demonstrator Convertor (TDC) was recently tested to verify its survivability and capability of withstanding its expected launch random vibration environment. The TDC was fully operational (producing power) during the random vibration testing. The output power of the convertor was measured during the testing, and these results are discussed in this paper. Numerous accelerometers and force gauges were also present which provided information on the dynamic characteristics of the TDC and an indication of any possible damage due to vibration. These measurements will also be discussed in this paper. The vibration testing of the Stirling TDC was extremely successful. The TDC survived all its vibration testing with no structural damage or functional performance degradation. As a result of this testing, the Stirling convertor's capability to withstand vibration has been demonstrated, enabling its usage in future spacecraft power systems.

  16. Piston rod seal for a Stirling engine

    DOEpatents

    Shapiro, Wilbur

    1984-01-01

    In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal.

  17. "Starfish" Heater Head For Stirling Engine

    NASA Technical Reports Server (NTRS)

    Vitale, N.

    1993-01-01

    Proposed "starfish" heater head for Stirling engine enables safe use of liquid sodium as heat-transfer fluid. Sodium makes direct contact with heater head but does not come in contact with any structural welds. Design concept minimizes number of, and simplifies nonstructural thermal welds and facilitates inspection of such welds.

  18. V160 Stirling engine program update

    SciTech Connect

    Johansson, L.; Torstensson, B.; Williams, T. Y.; Houtman, W.H.; Monahan, R.

    1988-01-01

    Development efforts being made toward the preproduction stage of the V160 Stirling engine are examined. The history of continued reliability encompassing all engine models is reviewed, and efforts towards engine manufacturing and cost reduction are addressed. A preview is given of the initial product line based on the V160 engine and substantiated through testing of the offered configurations.

  19. NASA Lewis Stirling engine computer code evaluation

    SciTech Connect

    Sullivan, T.J.

    1989-01-01

    In support of the US Department of Energy's Stirling Engine Highway Vehicle Systems program, the NASA Lewis Stirling engine performance code was evaluated by comparing code predictions without engine-specific calibration factors to GPU-3, P-40, and RE-1000 Stirling engine test data. The error in predicting power output was /minus/11 percent for the P-40 and 12 percent for the RE-1000 at design conditions and 16 percent for the GPU-3 at near-design conditions (2000 rpm engine speed versus 3000 rpm at design). The efficiency and heat input predictions showed better agreement with engine test data than did the power predictions. Concerning all data points, the error in predicting the GPU-3 brake power was significantly larger than for the other engines and was mainly a result of inaccuracy in predicting the pressure phase angle. Analysis into this pressure phase angle prediction error suggested that improvement to the cylinder hysteresis loss model could have a significant effect on overall Stirling engine performance predictions. 13 refs., 26 figs., 3 tabs.

  20. NASA Lewis Stirling engine computer code evaluation

    NASA Technical Reports Server (NTRS)

    Sullivan, Timothy J.

    1989-01-01

    In support of the U.S. Department of Energy's Stirling Engine Highway Vehicle Systems program, the NASA Lewis Stirling engine performance code was evaluated by comparing code predictions without engine-specific calibration factors to GPU-3, P-40, and RE-1000 Stirling engine test data. The error in predicting power output was -11 percent for the P-40 and 12 percent for the Re-1000 at design conditions and 16 percent for the GPU-3 at near-design conditions (2000 rpm engine speed versus 3000 rpm at design). The efficiency and heat input predictions showed better agreement with engine test data than did the power predictions. Concerning all data points, the error in predicting the GPU-3 brake power was significantly larger than for the other engines and was mainly a result of inaccuracy in predicting the pressure phase angle. Analysis into this pressure phase angle prediction error suggested that improvements to the cylinder hysteresis loss model could have a significant effect on overall Stirling engine performance predictions.

  1. Measurements with a recuperative superfluid Stirling refrigerator

    SciTech Connect

    Watanabe, A.; Swift, G.W.; Brisson, J.G.

    1995-08-01

    A superfluid Stirling refrigerator cooled to 168 mK using a 4.9% {sup 3}He- {sup 4}He mixture and exhausting its waste heat at 383 mK. Cooling power versus temperature and speed is presented for 4.9%, 17%, and 36% mixtures. At the highest concentration, a dissipation mechanism of unknown origin is observed.

  2. Testing of a Stirling cycle cooler

    SciTech Connect

    Chen, F.C.; Keshock, E.G.; Murphy, R.W.

    1988-09-01

    Stirling cycle coolers have long been used as low temperature refrigeration devices. They are relatively compact, reliable, commercially available, and use helium as the working fluid. The Stirling cycle, in principle, can be used for household refrigeration and heat pumping applications as well. Currently, these applications are almost entirely provided by the vapor compression technology using chlorofluorocarbons (CFCs) as working fluids. It has been known that CFCs cause depletion of the ozone layer that protects the earth against harmful levels of ultraviolet radiation from the sun. A recent report of a ''hole'' in the ozone layer above Antarctica and of possible environmental and health consequences from ozone depletion aroused public attention. The urgent need to reduce the future used of CFCs should instigate investigation of non-CFC alternative technologies. The Stirling cooler technology, which does not use CFCs, could be a viable alternative. A laboratory test of the performance of a Stirling cooler is reported and its implications for household refrigeration are explored. 11 refs., 6 figs., 2 tabs.

  3. Stirling-Cycle Refrigerator Containing Piezoelectric Pumps

    NASA Technical Reports Server (NTRS)

    Jalink, Antony, Jr.; Hellbaum, R. F.

    1995-01-01

    Advanced Stirling-cycle cryogenic apparatus suitable for cooling sensitive infrared detectors to very low temperatures. Working fluid in refrigerator helium. Working fluid compressed and circulated by three piezoelectrically actuated diaphragm pumps offering advantages of greater reliability, relative simplicity, and lower cost.

  4. Double acting stirling engine piston ring

    DOEpatents

    Howarth, Roy B.

    1986-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  5. NASA's Radioisotope Power Systems - Plans

    NASA Technical Reports Server (NTRS)

    Hamley, John A.; Mccallum, Peter W.; Sandifer, Carl E., II; Sutliff, Thomas J.; Zakrajsek, June F.

    2015-01-01

    NASA's Radioisotope Power Systems (RPS) Program continues to plan and implement content to enable planetary exploration where such systems could be needed, and to prepare more advanced RPS technology for possible infusion into future power systems. The 2014-2015 period saw significant changes, and strong progress. Achievements of near-term objectives have enabled definition of a clear path forward in which payoffs from research investments and other sustaining efforts can be applied. The future implementation path is expected to yield a higher-performing thermoelectric generator design, a more isotope-fuel efficient system concept design, and a robust RPS infrastructure maintained effectively within both NASA and the Department of Energy. This paper describes recent work with an eye towards the future plans that result from these achievements.

  6. Radioisotope scanning in osseous sarcoidosis

    SciTech Connect

    Rohatgi, P.K.

    1980-01-01

    Technetium-99m (/sup 99m/Tc)-labeled pyrophosphate or diphosphonate compounds and gallium-67 citrate (/sup 67/Ga) are two radionuclide scanning agents that are in widespread use in clinical practice. Technetium-99m pyrophosphate is used extensively for bone scanning to detect metastatic bone disease, benign bone tumors, osteomyelitis, benign hypertrophic osteoarthropathy, and Paget's disease. Only two reports describe abnormal /sup 99m/Tc/ pyrophosphate bone scans in four patients with osseous sarcoidosis. Gallium-67 scans are used primarily to localize neoplastic or inflammatory lesions anywhere in the body. In recent years /sup 67/Ga scans have also been used to detect the presence of both pulmonary and extrapulmonary sarcoidosis, but there are no reports describing abnormal uptake of gallium in patients with osseous sarcoidosis. This report describes experience with radioisotope scanning in two patients with osseous sarcoidosis.

  7. BEST medical radioisotope production cyclotrons

    SciTech Connect

    Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Johnson, Richard R.; Gelbart, W. Z.

    2013-04-19

    Best Cyclotron Systems Inc (BCSI) is currently developing 14 MeV, 25 MeV, 35MeV and 70MeV cyclotrons for radioisotope production and research applications as well as the entire spectrum of targets and nuclear synthesis modules for the production of Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT) and radiation therapy isotopes. The company is a subsidiary of Best Medical International, renowned in the field of medical instrumentation and radiation therapy. All cyclotrons have external negative hydrogen ion sources, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity ranges from 400 {mu}A to 1000 {mu}A, depending on the cyclotron energy and application.

  8. BEST medical radioisotope production cyclotrons

    NASA Astrophysics Data System (ADS)

    Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Gelbart, W. Z.; Johnson, Richard R.

    2013-04-01

    Best Cyclotron Systems Inc (BCSI) is currently developing 14 MeV, 25 MeV, 35MeV and 70MeV cyclotrons for radioisotope production and research applications as well as the entire spectrum of targets and nuclear synthesis modules for the production of Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT) and radiation therapy isotopes. The company is a subsidiary of Best Medical International, renowned in the field of medical instrumentation and radiation therapy. All cyclotrons have external negative hydrogen ion sources, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity ranges from 400 μA to 1000 μA, depending on the cyclotron energy and application [1].

  9. Miniature Radioisotope Thermoelectric Power Cubes

    NASA Technical Reports Server (NTRS)

    Patel, Jagdish U.; Fleurial, Jean-Pierre; Snyder, G. Jeffrey; Caillat, Thierry

    2004-01-01

    Cube-shaped thermoelectric devices energized by a particles from radioactive decay of Cm-244 have been proposed as long-lived sources of power. These power cubes are intended especially for incorporation into electronic circuits that must operate in dark, extremely cold locations (e.g., polar locations or deep underwater on Earth, or in deep interplanetary space). Unlike conventional radioisotope thermoelectric generators used heretofore as central power sources in some spacecraft, the proposed power cubes would be small enough (volumes would range between 0.1 and 0.2 cm3) to play the roles of batteries that are parts of, and dedicated to, individual electronic-circuit packages. Unlike electrochemical batteries, these power cubes would perform well at low temperatures. They would also last much longer: given that the half-life of Cm-244 is 18 years, a power cube could remain adequate as a power source for years, depending on the power demand in its particular application.

  10. An experimental study on a model Stirling engine car

    SciTech Connect

    Sohma, Yutaka; Wu, Chungming; Isshiki, Seita; Ushiyama, Izumi

    1999-07-01

    A Stirling engine is a mechanical device that operates on a closed regenerative thermodynamic cycle, with cyclic compression and expansion of the working fluid at different temperature levels. The flow is controlled by volume changes, and there exists a net conversion of the heat to work. Stirling engines are ideally suited to off-grid electric power generation because of their multi-fuel capability, potentially high efficiency and low noise. The first model Stirling Techno-rally was held in August 1997 for further promotion of the clean and quiet Stirling engine as one of the Centennial Anniversary events of JSME. In the race, more than one hundred cars competed for the time on a course of 13 meters length and 30 centimeters width. In Ashikaga Institute of Technology, a model Stirling engine car Ashikaga Gekkoh was made for this event. In this paper the authors report on this model car that won the championship of the Stirling Techno-rally.

  11. US Department of Energy radioisotope customers with summary of radioisotope shipments, FY 1988

    SciTech Connect

    Van Houten, N.C.

    1989-06-01

    Pacific Northwest Laboratory (PNL) prepared this edition of the radioisotope customer list at the request of the Office of Health and Environmental Research (ER-73), Office of Energy Research, US Department of Energy (DOE). This is the 25th report in a series dating from 1964. This report covers DOE radioisotope sales and distribution activities by its facilities to domestic, foreign and other DOE facilities for FY 1988. The report is divided into five sections: radioisotope suppliers, facility contacts, and radioisotopes or services supplied; a list of customers, suppliers, and radioisotopes purchased; a list of radioisotopes purchased cross-referenced to customer numbers; geographic locations of radioisotope customers; and radioisotope sales and transfers -- FY 1988. Radioisotopes not previously reported in this series of reports were argon-37, arsenic-72, arsenic-73, bismuth-207, gadolinium-151, rhenium-188, rhodium-101, selenium-72, xenon-123 and zirconium-88. The total value of DOE radioisotope sales for FY 1988 was $11.1 million, an increase of 3% from FY 1987.

  12. Advanced radioisotope power sources for future deep space missions

    NASA Astrophysics Data System (ADS)

    Nilsen, Erik N.

    2001-02-01

    The use of Radioisotope Thermoelectric Generators (RTGs) has been well established for deep space mission applications. The success of the Voyager, Galileo, Cassini and numerous other missions proved the efficacy of these technologies in deep space. Future deep space missions may also require Advanced Radioisotope Power System (ARPS) technologies to accomplish their goals. In the Exploration of the Solar System (ESS) theme, several missions are in the planning stages or under study that would be enabled by ARPS technology. Two ESS missions in the planning stage may employ ARPS. Currently planned for launch in 2006, the Europa Orbiter mission (EO) will perform a detailed orbital exploration of Jupiter's moon Europa to determine the presence of liquid water under the icy surface. An ARPS based upon Stirling engine technology is currently baselined for this mission. The Pluto Kuiper Express mission (PKE), planned for launch in 2004 to study Pluto, its moon Charon, and the Kuiper belt, is baselined to use a new RTG (F-8) assembled from parts remaining from the Cassini spare RTG. However, if this unit is unavailable, the Cassini spare RTG (F-5) or ARPS technologies would be required. Future missions under study may also require ARPS technologies. Mission studies are now underway for a detailed exploration program for Europa, with multiple mission concepts for landers and future surface and subsurface explorers. For the orbital phase of these missions, ARPS technologies may provide the necessary power for the spacecraft and orbital telecommunications relay capability for landed assets. For extended surface and subsurface operations, ARPS may provide the power for lander operations and for drilling. Saturn Ring Observer (SRO) will perform a detailed study of Saturn's rings and ring dynamics. The Neptune Orbiter (NO) mission will perform a detailed multi disciplinary study of Neptune. Titan Explorer (TE) will perform in-situ exploration of Saturn's moon Titan, with both

  13. Structural design of Stirling engine with free pistons

    NASA Astrophysics Data System (ADS)

    Matusov, Jozef; Gavlas, Stanislav; Malcho, Milan

    2014-08-01

    Stirling engine is a device that converts thermal energy to mechanical work, which is mostly used to drive a generator of electricity. Advantage of Stirling engine is that it works with closed-cycle, where working medium is regularly cooled and heated, which acts on the working piston. This engine can be made in three modifications - alpha, beta, gamma. This paper discusses the design of the gamma Stirling engine with free pistons.

  14. A stirling engine computer model for performance calculations

    NASA Technical Reports Server (NTRS)

    Tew, R.; Jefferies, K.; Miao, D.

    1978-01-01

    To support the development of the Stirling engine as a possible alternative to the automobile spark-ignition engine, the thermodynamic characteristics of the Stirling engine were analyzed and modeled on a computer. The modeling techniques used are presented. The performance of an existing rhombic-drive Stirling engine was simulated by use of this computer program, and some typical results are presented. Engine tests are planned in order to evaluate this model.

  15. Non-heat pipe receiver/p-40 Stirling engine

    NASA Technical Reports Server (NTRS)

    Haglund, R. A.

    1981-01-01

    The technology for a full-up hybrid dish-Stirling Solar Thermal Power system is discussed. Overall solar-to-electric efficiency for the dish-Stirling system demonstration is approximately 30%. Hybrid operation is provided by fossil fuel combustion augmentation, which enables the Stirling engine to operate continuously at constant speed and power, regardless of insolation level, thus providing the capability to operate on cloudy days and at night.

  16. A Stirling engine with a liquid working substance

    NASA Astrophysics Data System (ADS)

    Swift, G. W.

    1989-06-01

    A theoretical and experimental study of a Stirling engine using a liquid (propylene) as its working substance is presented. This is the first experimental work on liquid Stirling engines (or Malone engines) since the 1920s. Liquid-Stirling technology appears advantageous to conventional freon-based Rankine-cycle technology in many applications. The theory developed here is simple, intuitive, and modular because of the nature of liquid working fluids and because the temperature spanned by liquid Stirling engines is not large. The experimental engine is extremely versatile, and can operate as either a heat pump or prime mover. Extensive measurements with it are in substantial agreement with the simple theory.

  17. Small Radioisotope Power System Testing at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Dugala, Gina; Bell, Mark; Oriti, Salvatore; Fraeman, Martin; Frankford, David; Duven, Dennis

    2013-01-01

    In April 2009, NASA Glenn Research Center (GRC) formed an integrated product team (IPT) to develop a Small Radioisotope Power System (SRPS) utilizing a single Advanced Stirling Convertor (ASC) with passive balancer. A single ASC produces approximately 80 We making this system advantageous for small distributed lunar science stations. The IPT consists of Sunpower, Inc., to provide the single ASC with a passive balancer, The Johns Hopkins University Applied Physics Laboratory (JHUAPL) to design an engineering model Single Convertor Controller (SCC) for an ASC with a passive balancer, and NASA GRC to provide technical support to these tasks and to develop a simulated lunar lander test stand. The single ASC with a passive balancer, simulated lunar lander test stand, and SCC were delivered to GRC and were tested as a system. The testing sequence at GRC included SCC fault tolerance, integration, electromagnetic interference (EMI), vibration, and extended operation testing. The SCC fault tolerance test characterized the SCCs ability to handle various fault conditions, including high or low bus power consumption, total open load or short circuit, and replacing a failed SCC card while the backup maintains control of the ASC. The integrated test characterized the behavior of the system across a range of operating conditions, including variations in cold-end temperature and piston amplitude, including the emitted vibration to both the sensors on the lunar lander and the lunar surface. The EMI test characterized the AC and DC magnetic and electric fields emitted by the SCC and single ASC. The vibration test confirms the SCCs ability to control the single ASC during launch. The extended operation test allows data to be collected over a period of thousands of hours to obtain long term performance data of the ASC with a passive balancer and the SCC. This paper will discuss the results of each of these tests.

  18. Small Radioisotope Power System at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Dugala, Gina M.; Fraeman, Martin; Frankford, David P.; Duven, Dennis; Shamkovich, Andrei; Ambrose, Hollis; Meer, David W.

    2012-01-01

    In April 2009, NASA Glenn Research Center (GRC) formed an integrated product team (IPT) to develop a Small Radioisotope Power System (SRPS) utilizing a single Advanced Stirling Convertor (ASC) with passive balancer for possible use by the International Lunar Network (ILN) program. The ILN program is studying the feasibility of implementing a multiple node seismometer network to investigate the internal lunar structure. A single ASC produces approximately 80 W(sub e) and could potentially supply sufficient power for that application. The IPT consists of Sunpower, Inc., to provide the single ASC with balancer, The Johns Hopkins University Applied Physics Laboratory (JHU/APL) to design an engineering model Single Convertor Controller (SCC) for an ASC with balancer, and NASA GRC to provide technical support to these tasks and to develop a simulated lunar lander test stand. A controller maintains stable operation of an ASC. It regulates the alternating current produced by the linear alternator of the convertor, provides a specified output voltage, and maintains operation at a steady piston amplitude and hot end temperature. JHU/APL also designed an ASC dynamic engine/alternator simulator to aid in the testing and troubleshooting of the SCC. This paper describes the requirements, design, and development of the SCC, including some of the key challenges and the solutions chosen to overcome those issues. In addition, it describes the plans to analyze the effectiveness of a passive balancer to minimize vibration from the ASC, characterize the effect of ASC vibration on a lunar lander, characterize the performance of the SCC, and integrate the single ASC, SCC, and lunar lander test stand to characterize performance of the overall system.

  19. Potential Applications for Radioisotope Power Systems in Support of Human Exploration Missions

    NASA Technical Reports Server (NTRS)

    Cataldo, Robert L.; Colozza, Anthony J.; Schmitz, Paul C.

    2013-01-01

    Radioisotope power systems (RPS) for space applications have powered over 27 U.S. space systems, starting with Transit 4A and 4B in 1961, and more recently with the successful landing of the Mars Science Laboratory rover Curiosity in August 2012. RPS enable missions with destinations far from the Sun with faint solar flux, on planetary surfaces with dense or dusty atmospheres, and at places with long eclipse periods where solar array sizes and energy storage mass become impractical. RPS could also provide an enabling capability in support of human exploration activities. It is envisioned that with the higher power needs of most human mission concepts, a high efficiency thermal-to-electric technology would be required such as the Advanced Stirling Radioisotope generator (ASRG). The ASRG should be capable of a four-fold improvement in efficiency over traditional thermoelectric RPS. While it may be impractical to use RPS as a main power source, many other applications could be considered, such as crewed pressurized rovers, in-situ resource production of propellants, back-up habitat power, drilling, any mobile or remote activity from the main base habitat, etc. This paper will identify potential applications and provide concepts that could be a practical extension of the current ASRG design in providing for robust and flexible use of RPS on human exploration missions.

  20. List of DOE radioisotope customers with summary of radioisotope shipments, FY 1983

    SciTech Connect

    Baker, D.A.

    1984-08-01

    This document lists DOE's radioisotope production and distribution activities by its facilities at Argonne National Laboratory; Pacific Northwest Laboratory; Idaho Operations Office; Los Alamos National Laboratory; Oak Ridge National Laboratory; Savannah River Plant; and UNC Nuclear Industries, Inc. The information is divided into five sections: isotope suppliers, facility contacts, and isotopes or services supplied; lists of customers, suppliers and isotopes purchased; list of isotopes purchased cross-referenced to customer codes; geographic locations of radioisotope customers; and radioisotope sales and transfers - FY 1983.

  1. List of DOE radioisotope customers with summary of radioisotope shipments, FY 1984

    SciTech Connect

    Baker, D.A.

    1985-08-01

    This edition of the radioisotope customer list was prepared at the request of the Office of Health and Environmental Research (ER-73), Office of Energy Research, Department of Energy (DOE). This document describes radioisotope distribution from DOE facilities to private firms including foreign and other DOE facilities. The information is divided into five sections: (1) isotope suppliers, facility contacts, and isotopes or services supplied; (2) customers, suppliers, and isotopes purchased; (3) isotopes purchased cross-referenced with customer numbers; (4) geographic locations of radioisotope customers; and (5) radioisotope sales and transfers - FY 1984.

  2. Advanced Radioisotope Power Systems Segmented Thermoelectric Research

    NASA Technical Reports Server (NTRS)

    Caillat, Thierry

    2004-01-01

    Flight times are long; - Need power systems with >15 years life. Mass is at an absolute premium; - Need power systems with high specific power and scalability. 3 orders of magnitude reduction in solar irradiance from Earth to Pluto. Nuclear power sources preferable. The Overall objective is to develop low mass, high efficiency, low-cost Advanced Radioisotope Power System with double the Specific Power and Efficiency over state-of-the-art Radioisotope Thermoelectric Generators (RTGs).

  3. Composite Matrix Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Knowles, Timothy R.

    1997-01-01

    This project concerns the design, fabrication and testing of carbon regenerators for use in Stirling power convertors. Radial fiber design with nonmetallic components offers a number of potential advantages over conventional steel regenerators: reduced conduction and pressure drop losses, and the capability for higher temperature, higher frequency operation. Diverse composite fabrication methods are explored and lessons learned are summarized. A pulsed single-blow test rig has been developed that has been used for generating thermal effectiveness data for different flow velocities. Carbon regenerators have been fabricated by carbon vapor infiltration of electroflocked preforms. Performance data in a small Stirling engine are obtained. Prototype regenerators designed for the BP-1000 power convertor were fabricated and delivered to NASA-Lewis.

  4. Stirling engine supporting research and technology

    NASA Technical Reports Server (NTRS)

    Tomazic, W. A.

    1985-01-01

    The supporting research and technology effort is intended to provide technical support to the current engine program and also to investigate advanced concepts for the next generation of Stirling engines. Technical areas represented are: seals, materials, engine experiments, combustion, system analysis, cseramics, and tribology. A collage of more recent work in each area is presented. Under seals, analysis and some experimental data on the effect of wear on rod seal performance is presented. The material work described concerns the effect of water content on hydrogen permeation. Results of experiments with the Philips' Advenco engine are presented. A comparison is made of two combustor nozzles, an air atomizing and an ultrasonic atomizing nozzle. A new venture in systems analysis to provide more rigorous Stirling engine simulation is discussed. The results of hydrogen corrosion tests on silicon carbide are presented. Friction and wear tests on candidate materials for engine hot ring tests are discussed.

  5. Basic principles of the Stirling cycle

    NASA Astrophysics Data System (ADS)

    1983-03-01

    The basic principles of the Stirling cycle are outlined. From an elementary theory the general properties of the cycle are derived with a discussion of the most important losses. The performance of the fundamental and ideal (isothermal) cycle are described. The actual cycle, which differs from the ideal one by the occurrence of losses is also described. In the ideal Stirling cycle, the cold is produced by the reversible expansion of a gas. The gas performs a closed cycle, during which it is alternately compressed at ambient temperature in a compression space and expanded at the desired low temperature in an expansion space, thereby reciprocating between these spaces through one connecting duct, wherein a regenerator provides for the heat exchange between the outgoing and the returning gas flow. The problem of how to minimize the total sum of the losses is examined.

  6. Improved Stirling engine performance using jet impingement

    NASA Technical Reports Server (NTRS)

    Johnson, D. C.; Britt, E. J.; Thieme, L. G.

    1982-01-01

    Of the many factors influencing the performance of a Stirling engine, that of transferring the combustion gas heat into the working fluid is crucial. By utilizing the high heat transfer rates obtainable with a jet impingement heat transfer system, it is possible to reduce the flame temperature required for engine operation. Also, the required amount of heater tube surface area may be reduced, resulting in a decrease in the engine nonswept volume and a related increase in engine efficiency. A jet impingement heat transfer system was designed by Rasor Associates, Inc., and tested in the GPU-3 Stirling engine at the NASA Lewis Research Center. For a small penalty in pumping power (less than 0.5% of engine output) the jet impingement heat transfer system provided a higher combustion-gas-side heat transfer coefficient and a smoothing of heater temperature profiles resulting in lower combustion system temperatures and a 5 to 8% increase in engine power output and efficiency.

  7. Stirling Colgate and Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Lamb, Donald

    2014-10-01

    Even before the discovery of gamma-ray bursts (GRBs), Stirling Colgate proposed that bursts of x rays and gamma rays might be produced by a relativistic shock created in the supernova explosion of a massive star. We trace the scientific story of GRBs from their detection to the present, highlighting along the way Stirling's interest in them and his efforts to understand them. We summarize our current understanding that short, soft, repeating bursts are produced by magnetic neutron stars; short, hard bursts are produced by the mergers of neutron star-neutron star binaries; and long, hard bursts are produced by the core collapse of massive stars that have lost their hydrogen and helium envelopes. We then discuss some important open questions about GRBs and how they might be answered. We conclude by describing the recent serendipitous discovery of an x-ray burst of exactly the kind he proposed, and the insights into core collapse supernovae and GRBs that it provided.

  8. A Saturn Ring Observer Mission Using Multi-Mission Radioisotope Power Systems

    SciTech Connect

    Abelson, Robert D.; Spilker, Thomas R.; Shirley, James H.

    2006-01-20

    Saturn remains one of the most fascinating planets within the solar system. To better understand the complex ring structure of this planet, a conceptual Saturn Ring Observer (SRO) mission is presented that would spend one year in close proximity to Saturn's A and B rings, and perform detailed observations and measurements of the ring particles and electric and magnetic fields. The primary objective of the mission would be to understand ring dynamics, including the microphysics of individual particles and small scale (meters to a few kilometers) phenomena such as particle agglomeration behavior. This would be accomplished by multispectral imaging of the rings at multiple key locations within the A and B rings, and by ring-particle imaging at an unprecedented resolution of 0.5 cm/pixel. The SRO spacecraft would use a Venus-Earth-Earth-Jupiter Gravity Assist (VEEJGA) and be aerocaptured into Saturn orbit using an advanced aeroshell design to minimize propellant mass. Once in orbit, the SRO would stand off from the ring plane 1 to 1.4 km using chemical thrusters to provide short propulsive maneuvers four times per revolution, effectively causing the SRO vehicle to 'hop' above the ring plane. The conceptual SRO spacecraft would be enabled by the use of a new generation of multi-mission Radioisotope Power Systems (RPSs) currently being developed by NASA and DOE. These RPSs include the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) and Stirling Radioisotope Generator (SRG). The RPSs would generate all necessary electrical power ({>=}330 We at beginning of life) during the 10-year cruise and 1-year science mission ({approx}11 years total). The RPS heat would be used to maintain the vehicle's operating and survival temperatures, minimizing the need for electrical heaters. Such a mission could potentially launch in the 2015-2020 timeframe, with operations at Saturn commencing in approximately 2030.

  9. A Saturn Ring Observer Mission Using Multi-Mission Radioisotope Power Systems

    NASA Astrophysics Data System (ADS)

    Abelson, Robert D.; Spilker, Thomas R.; Shirley, James H.

    2006-01-01

    Saturn remains one of the most fascinating planets within the solar system. To better understand the complex ring structure of this planet, a conceptual Saturn Ring Observer (SRO) mission is presented that would spend one year in close proximity to Saturn's A and B rings, and perform detailed observations and measurements of the ring particles and electric and magnetic fields. The primary objective of the mission would be to understand ring dynamics, including the microphysics of individual particles and small scale (meters to a few kilometers) phenomena such as particle agglomeration behavior. This would be accomplished by multispectral imaging of the rings at multiple key locations within the A and B rings, and by ring-particle imaging at an unprecedented resolution of 0.5 cm/pixel. The SRO spacecraft would use a Venus-Earth-Earth-Jupiter Gravity Assist (VEEJGA) and be aerocaptured into Saturn orbit using an advanced aeroshell design to minimize propellant mass. Once in orbit, the SRO would stand off from the ring plane 1 to 1.4 km using chemical thrusters to provide short propulsive maneuvers four times per revolution, effectively causing the SRO vehicle to ``hop'' above the ring plane. The conceptual SRO spacecraft would be enabled by the use of a new generation of multi-mission Radioisotope Power Systems (RPSs) currently being developed by NASA and DOE. These RPSs include the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) and Stirling Radioisotope Generator (SRG). The RPSs would generate all necessary electrical power (>=330 We at beginning of life) during the 10-year cruise and 1-year science mission (~11 years total). The RPS heat would be used to maintain the vehicle's operating and survival temperatures, minimizing the need for electrical heaters. Such a mission could potentially launch in the 2015-2020 timeframe, with operations at Saturn commencing in approximately 2030.

  10. Construction of a thermoacoustic Stirling cooler

    NASA Astrophysics Data System (ADS)

    Ueda, Yuki; Biwa, Tetsushi; Yazaki, Taichi; Mizutani, Uichiro

    2003-05-01

    An efficient thermoacoustic prime mover has been built by Backhaus and Swift (Nature 339 (1999) 335). They have demonstrated that this engine produces an acoustic power with the thermal efficiency of 30%. We succeed in developing a thermoacoustic Stirling cooler as its application by inserting a regenerator inside the prime mover. Since this cooler has no moving parts and has a potential to be an efficient device, it is a powerful tool to generate low temperatures.

  11. Direct-Circulation Stirling-Cycle Refrigerator

    NASA Technical Reports Server (NTRS)

    Ellison, Woody; Kohuth, Randall, Sr.

    1995-01-01

    In proposed cryogenic system, cold working fluid (helium) circulated directly from Stirling-cycle refrigerator machinery through loop of tubing to provide 15 W of cooling power at temperature of 80 K to scientific instruments or other devices located at some distance from machinery. (Separation of cooled devices from machinery may be dictated by engineering requirements including, need to isolate cooled devices from vibrations of machinery.) Advantages include less complexity, smaller size, lighter weight, and lower power consumption.

  12. Cermet Coatings for Solar Stirling Space Power

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Raack, Taylor

    2004-01-01

    Cermet coatings, molecular mixtures of metal and ceramic are being considered for the heat inlet surface of a solar Stirling space power converter. This paper will discuss the solar absorption characteristics of as-deposited cermet coatings as well as the solar absorption characteristics of the coatings after heating. The role of diffusion and island formation, during the deposition process and during heating will also be discussed.

  13. Stirling Engine With Radial Flow Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Vitale, N.; Yarr, George

    1993-01-01

    Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.

  14. Sensitivity analysis of Stirling engine design parameters

    SciTech Connect

    Naso, V.; Dong, W.; Lucentini, M.; Capata, R.

    1998-07-01

    In the preliminary Stirling engine design process, the values of some design parameters (temperature ratio, swept volume ratio, phase angle and dead volume ratio) have to be assumed; as a matter of fact it can be difficult to determine the best values of these parameters for a particular engine design. In this paper, a mathematical model is developed to analyze the sensitivity of engine's performance variations corresponding to variations of these parameters.

  15. High-Temperature Materials For Stirling Engines

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1990-01-01

    Heat-resistant piston rings and linings increase engine efficiency. Report discusses research on materials for piston rings and cylinder coatings in automotive Stirling engines. Data from tests show cobalt-based alloy, Stellite 6B, good choice for piston rings and PS200, plasma-sprayed metal-bonded chromium carbide matrix with dispersed solid lubricants, functions well as cylinder coating. Materials make it possible to place piston rings at tops of pistons ("hot" piston rings) instead of at cooler bottoms.

  16. Resistance Heater Helps Stirling-Engine Research

    NASA Technical Reports Server (NTRS)

    Hoehn, F. W.

    1982-01-01

    Stirling engine heater head consists of 18 double-turn coils of tubing, each of which is tightly wrapped with resistance-heating element, through which working gas flows. Coils form a toroid about periphery of heater-head body. With new resistance heater, total circuit resistance can be selected independently of tube geometry by changing size of wires and/or number of wire wraps around each tube.

  17. Optimization of an irreversible Stirling regenerative cycle

    NASA Astrophysics Data System (ADS)

    Aragón-González, G.; Cano-Bianco, M.; León-Galicia, A.; Rivera-Camacho, J. M.

    2015-01-01

    In this work a Stirling regenerative cycle with some irreversibilities is analyzed. The analyzed irreversibilities are located at the heat exchangers. They receive a finite amount of heat and heat leakage occurs between both reservoirs. Using this model, power and the efficiency at maximum power are obtained. Some optimal design parameters for the exchanger heat areas and thermal conductances are presented. The relation between the power, efficiency and the results obtained are shown graphically.

  18. Stirling engine with air working fluid

    DOEpatents

    Corey, John A.

    1985-01-01

    A Stirling engine capable of utilizing air as a working fluid which includes a compact heat exchange module which includes heating tube units, regenerator and cooler positioned about the combustion chamber. This arrangement has the purpose and effect of allowing the construction of an efficient, high-speed, high power-density engine without the use of difficult to seal light gases as working fluids.

  19. Design of applicative 100 W Stirling engine

    SciTech Connect

    Kagawa, Noboru; Hirata, Koichi; Takeuchi, Makoto

    1995-12-31

    A small 100 W displacer type Stirling engine is being developed under a project of a JSME committee, RC127. The project consists of sixteen Japanese academic researchers of universities and governmental laboratories and eleven enterprise members related to the Stirling field. The engine has very unique features. Its expansion cylinder is heated by combustion gas or solar energy directly, and a simple cooling system rejects heat from the working fluid. A regenerator is built in the displacer piston with heating and cooling tubes in which the working fluid flows from/to outer tubes. The outer tubes for heating were located at the top of the expansion cylinder and the tubes for cooling are in the middle of the cylinder. The target performance is a 100 W output with 20% thermal efficiency at the operating conditions of 923 K expansion space temperature, 343 K compression space temperature, and 1,000 rpm. The 100 W displacer engine was designed based on a design manual established by a related JSME committee, RC110. It contains several guides to design for cycle, heat exchanger system, and mechanism of most Stirling cycle machines. The engine was designed by using the fundamental method, the second and third-order analyses accomplished with the newly arranged knowledge about each component. This paper presents the engine specifications and the theoretical analysis results. The design method is also introduced briefly.

  20. A 1050 K Stirling space engine design

    NASA Technical Reports Server (NTRS)

    Penswick, L. Barry

    1988-01-01

    As part of the NASA CSTI High Capacity Power Program on Conversion Systems for Nuclear Applications, Sunpower, Inc. completed for NASA Lewis a reference design of a single-cylinder free-piston Stirling engine that is optimized for the lifetimes and temperatures appropriate for space applications. The NASA effort is part of the overall SP-100 program which is a combined DOD/DOE/NASA project to develop nuclear power for space. Stirling engines have been identified as a growth option for SP-100 offering increased power output and lower system mass and radiator area. Superalloy materials are used in the 1050 K hot end of the engine; the engine temperature ratio is 2.0. The engine design features simplified heat exchangers with heat input by sodium heat pipes, hydrodynamic gas bearings, a permanent magnet linear alternator, and a dynamic balance system. The design shows an efficiency (including the alternator) of 29 percent and a specific mass of 5.7 kg/kW. This design also represents a significant step toward the 1300 K refractory Stirling engine which is another growth option of SP-100.

  1. Overheat Prevention in Solar-Powered Stirling Engines

    NASA Technical Reports Server (NTRS)

    Garrigus, W. E.; Pons, R. L.

    1982-01-01

    Proposed controller for solar-powered Stirling engine prevents engine from burning up when energy added by Sun exceeds that withdrawn by load. Head-temperature controller used existing electrical control unit of Stirling engine to regulate power output in response to head temperature. Power out-put is varied so keeps head temperature fairly constant.

  2. Solar Stirling receiver alternatives for the terrestrial solar application

    NASA Technical Reports Server (NTRS)

    Stearns, J.

    1986-01-01

    Concept studies have been completed for four dish-Stirling receivers, i.e., solar only and thermal storage receiver, each of which is either directly coupled or indirectly (heat pipe) coupled to the Stirling engine. The results of these studies are to be applied to systems benefit/cost analysis to determine the most desirable development approach.

  3. Stirling engines. (Latest citations from the Aerospace database). Published Search

    SciTech Connect

    Not Available

    1993-09-01

    The bibliography contains citations concerning fuel consumption, engine design and testing, computerized simulation, and lubrication systems relative to the Stirling cycle engine. Solar energy conversion research, thermodynamic efficiency, economics, and utilization for power generation and automobile engines are included. Materials used in Stirling engines are briefly evaluated. (Contains 250 citations and includes a subject term index and title list.)

  4. Tests Of A Stirling-Engine Power Converter

    NASA Technical Reports Server (NTRS)

    Dochat, George

    1995-01-01

    Report describes acceptance tests of power converter consisting of pair of opposed free-piston Stirling engines driving linear alternators. Stirling engines offer potential for extremely long life, high reliability, high efficiency at low hot-to-cold temperature ratios, and relatively low heater-head temperatures.

  5. Trends in dish-Stirling solar receiver designs

    SciTech Connect

    Diver, R.B.; Andraka, C.E.; Moreno, J.B.; Adkins, D.R.; Moss, T.A.

    1990-01-01

    The dish-Stirling solar energy system, because of its high efficiency, is a leading candidate for producing low-cost electric power from the sun. Dish-Stirling receiver design involves dealing with non-uniform and highly concentrated solar flux at high temperatures (700--800{degree}C) and, therefore, presents a variety of technical challenges. The technology is in the process of evolving from directly illuminated heater-head tube receivers'' to receivers that use refluxing (i.e., gravity assisted) liquid metals as an intermediate heat transfer fluid. Modern dish-Stirling development was initiated in the late 1970s by the Jet Propulsion Laboratory for the Department of Energy. The JPL technology development with United Stirling, Inc. involved the USAB 4.95 Stirling engine and directly illuminated heater-head tube receivers. This work eventually led to the successful demonstrations and world record efficiencies by Advanco Corp., and to the attempted commercialization of the technology by McDonnell Douglas Corp. The severe nature of concentrated solar flux and the potential advantages of heat-pipe technology have caused an evolution toward reflux'' receivers. These receivers are just beginning to be tested in the laboratory and integrated with dish-Stirling systems. In this paper, the history and current status of dish-Stirling receiver development are presented and discussed. The technical challenges to be addressed by the dish-Stirling community and the future plans at Sandia are outlined. 52 refs., 9 figs.

  6. Trends in dish-Stirling solar receiver designs

    NASA Astrophysics Data System (ADS)

    Diver, R. B.; Andraka, C. E.; Moreno, J. B.; Adkins, D. R.; Moss, T. A.

    The dish-Stirling solar energy system, because of its high efficiency, is a leading candidate for producing low cost electric power from the sun. Dish-Stirling receiver design involves dealing with non-uniform and highly concentrated solar flux at high temperatures (700 to 800 C) and, therefore, presents a variety of technical challenges. The technology is in the process of evolving from directly illuminated heater head tube receivers to receivers that use refluxing (i.e., gravity assisted) liquid metals as an intermediate heat transfer fluid. Modern dish-Stirling development was initiated in the late 1970s by the Jet Propulsion Laboratory for the Department of Energy. The JPL technology development with United Stirling, Inc. involved the USAB 4.95 Stirling engine and directly illuminated heater-head tube receivers. This work eventually led to the successful demonstrations and world record efficiencies by Advanco Corp., and to the attempted commercialization of the technology by McDonnell Douglas Corp. The severe nature of concentrated solar flux and the potential advantages of heat pipe technology have caused an evolution toward reflux receivers. These receivers are just beginning to be tested in the laboratory and integrated with dish-Stirling systems. In this paper, the history and current status of dish-Stirling receiver development are presented and discussed. The technical challenges to be addressed by the dish-Stirling community and the future plans at Sandia are outlined.

  7. Automotive Stirling Engine Mod 1 Design Review, Volume 1

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Risk assessment, safety analysis of the automotive stirling engine (ASE) mod I, design criteria and materials properties for the ASE mod I and reference engines, combustion are flower development, and the mod I engine starter motor are discussed. The stirling engine system, external heat system, hot engine system, cold engine system, and engine drive system are also discussed.

  8. Dish/Stirling for Department of Defense applications final report

    SciTech Connect

    Diver, R.B.; Menicucci, D.F.

    1997-03-01

    This report describes a Strategic Environmental Research and Development Program (SERDP) project to field a dish/Stirling system at a southwestern US military facility. This project entitled ``Dish/Stirling for DoD Applications`` was started in August 1993 and was completed in September 1996. The project`s objective was to assist military facilities to field and evaluate emerging environmentally sound and potentially economical dish/Stirling technology. Dish/Stirling technology has the potential to produce electricity at competitive costs while at the same time providing a secure and environmentally benign source of power. In accordance with the SERDP charter, this project leveraged a US Department of Energy (DOE) cost-shared project between Sandia National Laboratories and Cummins Power Generation, Inc. (CPG). CPG is a wholly owned subsidiary of Cummins Engine Company, a leading manufacturer of diesel engines. To accomplish this objective, the project called for the installation of a dish/Stirling system at a military facility to establish first-hand experience in the operation of a dish/Stirling system. To scope the potential DoD market for dish/Stirling technology and to identify the site for the demonstration, a survey of southwestern US military facilities was also conducted. This report describes the project history, the Cummins dish/Stirling system, results from the military market survey, and the field test results.

  9. On-Board Hydrogen Gas Production System For Stirling Engines

    DOEpatents

    Johansson, Lennart N.

    2004-06-29

    A hydrogen production system for use in connection with Stirling engines. The production system generates hydrogen working gas and periodically supplies it to the Stirling engine as its working fluid in instances where loss of such working fluid occurs through usage through operation of the associated Stirling engine. The hydrogen gas may be generated by various techniques including electrolysis and stored by various means including the use of a metal hydride absorbing material. By controlling the temperature of the absorbing material, the stored hydrogen gas may be provided to the Stirling engine as needed. A hydrogen production system for use in connection with Stirling engines. The production system generates hydrogen working gas and periodically supplies it to the Stirling engine as its working fluid in instances where loss of such working fluid occurs through usage through operation of the associated Stirling engine. The hydrogen gas may be generated by various techniques including electrolysis and stored by various means including the use of a metal hydride absorbing material. By controlling the temperature of the absorbing material, the stored hydrogen gas may be provided to the Stirling engine as needed.

  10. Stirling System Modeling for Space Nuclear Power Systems

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Johnson, Paul K.

    2008-01-01

    A dynamic model of a high-power Stirling convertor has been developed for space nuclear power systems modeling. The model is based on the Component Test Power Convertor (CTPC), a 12.5-kWe free-piston Stirling convertor. The model includes the fluid heat source, the Stirling convertor, output power, and heat rejection. The Stirling convertor model includes the Stirling cycle thermodynamics, heat flow, mechanical mass-spring damper systems, and the linear alternator. The model was validated against test data. Both nonlinear and linear versions of the model were developed. The linear version algebraically couples two separate linear dynamic models; one model of the Stirling cycle and one model of the thermal system, through the pressure factors. Future possible uses of the Stirling system dynamic model are discussed. A pair of commercially available 1-kWe Stirling convertors is being purchased by NASA Glenn Research Center. The specifications of those convertors may eventually be incorporated into the dynamic model and analysis compared to the convertor test data. Subsequent potential testing could include integrating the convertors into a pumped liquid metal hot-end interface. This test would provide more data for comparison to the dynamic model analysis.

  11. Stirling System Modeling for Space Nuclear Power Systems

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Johnson, Paul K.

    2007-01-01

    A dynamic model of a high-power Stirling convertor has been developed for space nuclear power systems modeling. The model is based on the Component Test Power Convertor (CTPC), a 12.5-kWe free-piston Stirling convertor. The model includes the fluid heat source, the Stirling convertor, output power and heat rejection. The Stirling convertor model includes the Stirling cycle thermodynamics, heat flow, mechanical mass-spring damper systems, and the linear alternator. The model was validated against test data. Both nonlinear and linear versions of the model were developed. The linear version algebraically couples two separate linear dynamic models; one model of the Stirling cycle and one model of the thermal system, through the pressure factors. Future possible uses of the Stirling system dynamic model are discussed. A pair of commercially available 1-kWe Stirling convertors is being purchased by NASA Glenn Research Center. The specifications of those convertors may eventually be incorporated into the dynamic model and analysis compared to the convertor test data. Subsequent potential testing could include integrating the convertors into a pumped liquid metal hot-end interface. This test would provide more data for comparison to the dynamic model analysis.

  12. Commercialization of dish-Stirling solar terrestrial systems

    NASA Technical Reports Server (NTRS)

    Ross, Brad; Penswick, Barry; White, Maury; Cooper, Martin; Farbman, Gerald

    1990-01-01

    The requirements for dish-Stirling commercialization are described. The requirements for practical terrestrial power systems, both technical and economic, are described. Solar energy availability, with seasonal and regional variations, is discussed. The advantages and disadvantages of hybrid operation are listed. The two systems described use either a 25-kW free-piston Stirling hydraulic engine or a 5-kW kinematic Stirling engine. Both engines feature long-life characteristics that result from the use of welded metal bellows as hermetic seals between the working gas and the crankcase fluid. The advantages of the systems, the state of the technology, and the challenges that remain are discussed. Technology transfer between solar terrestrial Stirling applications and other Stirling applications is predicted to be important and synergistic.

  13. A Study of Regenerator for a Personal Stirling Refrigerator

    NASA Astrophysics Data System (ADS)

    Murakami, Kazuhiko; Otaka, Toshio; Sakamoto, Moriyoshi; Yamaguchi, Hajime; Ota, Masahiro

    Stirling cycle system is expected as a gentle system to the earth, because the working fluid is completely free from chlorine molecules. A regenerator is the most important element of the Stirling cycle system for the performances. Flow in a regenerator is very complicated because the regenerator is made of matrix. So we are studying about Stirling cycle systems, especially the regenerator for a personal Stirling refrigerator. In this report, flow in a regenerator for a personal Stirling refrigerators is studied by using an original experimental set-up. Flow velocities and pressures at the outside of a matrix in a regenerator were measured in a round pipe. Flow effects of inlet or outlet shape and area for a regenerator were examined in detail. Pressure loss were measured at sides of a regenerator and friction factors were expressed as empirical formulas for each conditions of inlet shape of regenerator or matrixes.

  14. Performance of the Southern California Edison Company Stirling dish

    SciTech Connect

    Lopez, C.W.; Stone, K.W.

    1993-10-01

    McDonnell Douglas Astronautics Company (MDAC) and United Stirling AB of Sweden (USAB) formed a joint venture in 1982 to develop and produce a Stirling dish solar generating system. In this report, the six year development and testing program continued by the Southern California Edison Company (SCE) is described. Each Stirling dish module consists of a sun tracking dish concentrator developed by the MDAC and a Stirling engine driven power conversion unit (PCU) developed by USAB. The Stirling dish system demonstrated twice the peak and daily solar-to-electric conversion efficiency of any other system then under development. This system continues to set the performance standard for solar to electric systems being developed in the early 1990`s. Test data are presented and used to estimate the performance of a commercial system.

  15. Stirling engines for gas fired micro-cogen and cooling

    SciTech Connect

    Lane, N.W.; Beale, W.T.

    1996-12-31

    This paper describes the design and performance of free-piston Stirling engine-alternators particularly suited for use as natural gas fired micro-cogen and cooling devices. Stirling based cogen systems offer significant potential advantages over internal combustion engines in efficiency, to maintain higher efficiencies at lower power levels than than combustion engines significantly expands the potential for micro-cogen. System cost reduction and electric prices higher than the U.S. national average will have a far greater effect on commercial success than any further increase in Stirling engine efficiency. There exist niche markets where Stirling engine efficiency. There exist niche markets where Stirling based cogen systems are competitive. Machines of this design are being considered for production in the near future as gas-fired units for combined heat and power in sufficiently large quantities to assure competitive prices for the final unit.

  16. Hybrid sodium heat pipe receivers for dish/Stirling systems

    SciTech Connect

    Laing, D.; Reusch, M.

    1997-12-31

    The design of a hybrid solar/gas heat pipe receiver for the SBP 9 kW dish/Stirling system using a United Stirling AB V160 Stirling engine and the results of on-sun testing in alternative and parallel mode will be reported. The receiver is designed to transfer a thermal power of 35 kW. The heat pipe operates at around 800 C, working fluid is sodium. Operational options are solar-only, gas augmented and gas-only mode. Also the design of a second generation hybrid heat pipe receiver currently developed under a EU-funded project, based on the experience gained with the first hybrid receiver, will be reported. This receiver is designed for the improved SPB/L. and C.-10 kW dish/Stirling system with the reworked SOLO V161 Stirling engine.

  17. Commercialization of dish-Stirling solar terrestrial systems

    NASA Astrophysics Data System (ADS)

    Ross, Brad; Penswick, Barry; White, Maury; Cooper, Martin; Farbman, Gerald

    The requirements for dish-Stirling commercialization are described. The requirements for practical terrestrial power systems, both technical and economic, are described. Solar energy availability, with seasonal and regional variations, is discussed. The advantages and disadvantages of hybrid operation are listed. The two systems described use either a 25-kW free-piston Stirling hydraulic engine or a 5-kW kinematic Stirling engine. Both engines feature long-life characteristics that result from the use of welded metal bellows as hermetic seals between the working gas and the crankcase fluid. The advantages of the systems, the state of the technology, and the challenges that remain are discussed. Technology transfer between solar terrestrial Stirling applications and other Stirling applications is predicted to be important and synergistic.

  18. Performance of the Southern California Edison Company Stirling dish

    NASA Astrophysics Data System (ADS)

    Lopez, C. W.; Stone, K. W.

    1993-10-01

    McDonnell Douglas Astronautics Company (MDAC) and United Stirling AB of Sweden (USAB) formed a joint venture in 1982 to develop and produce a Stirling dish solar generating system. In this report, the six year development and testing program continued by the Southern California Edison Company (SCE) is described. Each Stirling dish module consists of a sun tracking dish concentrator developed by the MDAC and a Stirling engine driven power conversion unit (PCU) developed by USAB. The Stirling dish system demonstrated twice the peak and daily solar-to-electric conversion efficiency of any other system then under development. This system continues to set the performance standard for solar to electric systems being developed in the early 1990's. Test data are presented and used to estimate the performance of a commercial system.

  19. Radioisotope Production for Medical and Physics Applications

    NASA Astrophysics Data System (ADS)

    Mausner, Leonard

    2012-10-01

    Radioisotopes are critical to the science and technology base of the US. Discoveries and applications made as a result of the availability of radioisotopes span widely from medicine, biology, physics, chemistry and homeland security. The clinical use of radioisotopes for medical diagnosis is the largest sector of use, with about 16 million procedures a year in the US. The use of ^99Mo/^99mTc generator and ^18F make up the majority, but ^201Tl, ^123I, ^111In, and ^67Ga are also used routinely to perform imaging of organ function. Application of radioisotopes for therapy is dominated by use of ^131I for thyroid malignancies, ^90Y for some solid tumors, and ^89Sr for bone cancer, but production of several more exotic species such as ^225Ac and ^211At are of significant current research interest. In physics ^225Ra is of interest for CP violation studies, and the actinides ^242Am, ^249Bk, and ^254Es are needed as targets for experiments to create superheavy elements. Large amounts of ^252Cf are needed as a fission source for the CARIBU experiment at ANL. The process of radioisotope production is multidisciplinary. Nuclear physics input based on nuclear reaction excitation function data is needed to choose an optimum target/projectile in order to maximize desired isotope production and minimize unwanted byproducts. Mechanical engineering is needed to address issues of target heating, induced mechanical stress and material compatibility of target and claddings. Radiochemists are involved as well since chemical separation to purify the desired final radioisotope product from the bulk target and impurities is also usually necessary. Most neutron rich species are produced at a few government and university reactors. Other radioisotopes are produced in cyclotrons in the commercial sector, university/hospital based facilities, and larger devices at the DOE labs. The landscape of US facilities, the techniques involved, and current supply challenges will be reviewed.

  20. U.S. Space Radioisotope Power Systems and Applications: Past, Present and Future

    NASA Technical Reports Server (NTRS)

    Cataldo, Robert L.; Bennett, Gary L.

    2011-01-01

    Radioisotope power systems (RPS) have been essential to the U.S. exploration of outer space. RPS have two primary uses: electrical power and thermal power. To provide electrical power, the RPS uses the heat produced by the natural decay of a radioisotope (e.g., plutonium-238 in U.S. RPS) to drive a converter (e.g., thermoelectric elements or Stirling linear alternator). As a thermal power source the heat is conducted to whatever component on the spacecraft needs to be kept warm; this heat can be produced by a radioisotope heater unit (RHU) or by using the excess heat of a radioisotope thermoelectric generator (RTG). As of 2010, the U.S. has launched 41 RTGs on 26 space systems. These space systems have ranged from navigational satellites to challenging outer planet missions such as Pioneer 10/11, Voyager 1/2, Galileo, Ulysses, Cassini and the New Horizons mission to Pluto. In the fall of 2011, NASA plans to launch the Mars Science Laboratory (MSL) that will employ the new Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) as the principal power source. Hundreds of radioisotope heater units (RHUs) have been launched to provide warmth to Apollo 11, used to provide heating of critical components in a seismic experiment package, Pioneer 10/11, Voyager 1/2, Galileo, Cassini, Mars Pathfinder, MER rovers, etc. to provide temperature control to critical spacecraft electronics and other mechanical devices such as propulsion system propellant valves. A radioisotope (electrical) power source or system (RPS) consists of three basic elements: (1) the radioisotope heat source that provides the thermal power, (2) the converter that transforms the thermal power into electrical power and (3) the heat rejection radiator. Figure 1 illustrates the basic features of an RPS. The idea of a radioisotope power source follows closely after the early investigations of radioactivity by researchers such as Henri Becquerel (1852-1908), Marie Curie (1867-1935), Pierre Curie (1859