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Sample records for advanced stirling engine

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Compatibility of alternative fuels with advanced automotive gas turbine and stirling engines. A literature survey

    NASA Technical Reports Server (NTRS)

    Cairelli, J.; Horvath, D.

    1981-01-01

    The application of alternative fuels in advanced automotive gas turbine and Stirling engines is discussed on the basis of a literature survey. These alternative engines are briefly described, and the aspects that will influence fuel selection are identified. Fuel properties and combustion properties are discussed, with consideration given to advanced materials and components. Alternative fuels from petroleum, coal, oil shale, alcohol, and hydrogen are discussed, and some background is given about the origin and production of these fuels. Fuel requirements for automotive gas turbine and Stirling engines are developed, and the need for certain reseach efforts is discussed. Future research efforts planned at Lewis are described.

  9. Overview of advanced Stirling and gas turbine engine development programs and implications for solar thermal electrical applications

    SciTech Connect

    Alger, D.

    1984-03-01

    The DOE automotive advanced engine development projects managed by the NASA Lewis Research Center were described. These included one Stirling cycle engine development and two air Brayton cycle development. Other engine research activities included: (1) an air Brayton engine development sponsored by the Gas Research Institute, and (2) plans for development of a Stirling cycle engine for space use. Current and potential use of these various engines with solar parabolic dishes were discussed.

  10. Overview of Advanced Stirling and Gas Turbine Engine Development Programs and Implications for Solar Thermal Electrical Applications

    NASA Technical Reports Server (NTRS)

    Alger, D.

    1984-01-01

    The DOE automotive advanced engine development projects managed by the NASA Lewis Research Center were described. These included one Stirling cycle engine development and two air Brayton cycle development. Other engine research activities included: (1) an air Brayton engine development sponsored by the Gas Research Institute, and (2) plans for development of a Stirling cycle engine for space use. Current and potential use of these various engines with solar parabolic dishes were discussed.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Advanced high temperature materials for the energy efficient automotive Stirling engine

    NASA Technical Reports Server (NTRS)

    Titran, R. H.; Stephens, J. R.

    1984-01-01

    The Stirling Engine is under investigated jointly by the Department of Energy and NASA Lewis as an alternative to the internal combustion engine for automotive applications. 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 continuing supporting materials research and technology program has identified the wrought alloys CG-27 and 12RN72 and the cast alloys XF-818 and NASAUT 4G-A1 as candidate replacements for the cobalt containing alloys used in current prototype engines. Based on the materials research program in support of the automotive Stirling engine it is concluded that manufacture of the engine is feasible from low cost iron-base alloys rather than the cobalt alloys rather than the cobalt alloys used in prototype engines. This paper will present results of research that led to this conclusion.

  10. Advanced Stirling Radioisotope Generator Life Certification Plan

    NASA Technical Reports Server (NTRS)

    Rusick, Jeffrey J.; Zampino, Edward

    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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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…

  16. 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.

  17. IECEC '91; Proceedings of the 26th Intersociety Energy Conversion Engineering Conference, Boston, MA, Aug. 4-9, 1991. Vol. 5 - Renewable resource systems, Stirling engines and applications, systems and cycles

    SciTech Connect

    Not Available

    1991-01-01

    Various papers on energy conversion engineering are presented. The general topics considered are: developments in nuclear power, energy from waste and biomass, system performance and materials in photovoltaics, solar thermal energy, wind energy systems, Stirling cycle analysis, Stirling cycle power, Stirling component technology, Stirling cooler/heat pump developments, Stirling engine concepts, Stirling engine design and optimization, Stirling engine dynamics and response, Stirling engine solar terrestrial, advanced cogeneration, AMTC, fossil fuel systems and technologies, marine energy.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. IECEC '91; Proceedings of the 26th Intersociety Energy Conversion Engineering Conference, Boston, MA, Aug. 4-9, 1991. Vol. 5 - Renewable resource systems, stirling engines and applications, systems and cycles

    NASA Astrophysics Data System (ADS)

    Various papers on energy conversion enegineering are presented. The general topics considered are: developments in nuclear power, energy from waste and biomass, system performance and materials in photovoltaics, solar thermal energy, wind energy systems, Stirling cycle analysis, Stirling cycle power, Stirling component technology, Stirling cooler/heat pump developments, Stirling engine concepts, Stirling engine design and optimization, Stirling engine dynamics and response, Stirling engine solar terrestrial, advanced cogeneration, AMTC, fossil fuel systems and technologies, marine energy.

  5. Stirling engine with pressurized crankcase

    DOEpatents

    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.

  6. 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.

  7. 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.

  8. 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.

  9. High-Temperature Alloys for Automotive Stirling Engines

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Titran, R. H.

    1986-01-01

    Stirling engine is external-combustion engine that offers fuel economy, low emissions, low noise, and low vibrations. One of most critical areas in engine development concerns material selection for component parts. Alloys CG-27 and XF-818 identified capable of withstanding rigorous requirements of automotive Stirling engine. Alloys chosen for availability, performance, and manufacturability. Advanced iron-base alloys have potential for variety of applications, including stationary solar-power systems.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. The kinematic Stirling engine as an energy conversion subsystem for paraboloidal dish solar thermal plants

    NASA Technical Reports Server (NTRS)

    Bowyer, J. M.

    1984-01-01

    The potential of a suitably designed and economically manufactured Stirling engine as the energy conversion subsystem of a paraboloidal dish-Stirling solar thermal power module was estimated. Results obtained by elementary cycle analyses were shown to match quite well the performance characteristics of an advanced kinematic Stirling engine, the United Stirling P-40, as established by current prototypes of the engine and by a more sophisticated analytic model of its advanced derivative. In addition to performance, brief consideration was given to other Stirling engine criteria such as durability, reliability, and serviceability. Production costs were not considered here.

  16. 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.

  17. 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).

  18. 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.

  19. 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.

  20. 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.

  1. Progress toward the evolution of a Stirling Space Engine

    SciTech Connect

    Alger, D.L.

    1994-09-01

    Following the successful testing of the 25 kWe Space Power Demonstrator (SPD) engine in 1985, a Stirling Space Engine (SSE) technology advancement program was initiated. The program`s objective was to advance free-piston Stirling engine/alternator technology sufficiently so that a Stirling engine system may become a viable candidate for space power applications. Evolution of the SSE technology is planned to occur at three different engine heater temperature levels: 650, 1050, and 1300 K. These temperatures define three phases of technology development with the first phase involving the 650 K SPD engine. Technology development of the 650 K engine and preliminary design of the 1050 K engine will be discussed in this paper.

  2. 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.

  3. Solar powered Stirling engine

    SciTech Connect

    Meijer, R.J.

    1987-11-24

    In a solar dish module which comprises a dish which receives incident solar rays and reflects them to a focus at which is located the combination of a receiver and a heat engine organized and arranged so that the heat energy of the reflected solar rays collected at the receiver powers the engine, and wherein the receiver and heat engine are supported from the dish by a framework, the improvement is described which comprises journal means for journaling at least the engine on the framework to maintain certain predetermined spatial orientation for the engine in relation to the direction of gravity irrespective of spatial orientation of the dish.

  4. 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.

  5. 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)

  6. 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.

  7. 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.

  8. 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.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    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.

  11. 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).

  12. 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.

  13. 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.

  14. 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.

  15. Automotive Stirling engine: Mod II design report

    SciTech Connect

    Nightingale, N.P.

    1986-10-01

    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 II, also nullifies arguments that Stirling engines are heavy, expensive, unreliable, and demonstrate poor performance. Installed in a General Motors 1985 Chevrolet Celebrity car, this engine has a predicted combined fuel economy on unleaded gasoline of 17.5 km/L (41 mi/gal) - a value 50% above the current vehicle fleet average. The Mod II 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. 35 figs.

  16. 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.

  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. Variable displacement alpha-type Stirling engine

    NASA Astrophysics Data System (ADS)

    Homutescu, V. M.; Bălănescu, D. T.; Panaite, C. E.; Atanasiu, M. V.

    2016-08-01

    The basic design and construction of an alpha-type Stirling engine with on load variable displacement is presented. The variable displacement is obtained through a planar quadrilateral linkage with one on load movable ground link. The physico-mathematical model used for analyzing the variable displacement alpha-type Stirling engine behavior is an isothermal model that takes into account the real movement of the pistons. Performances and power adjustment capabilities of such alpha-type Stirling engine are calculated and analyzed. An exemplification through the use of the numerical simulation was performed in this regard.

  19. 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.

  20. 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.

  1. Recent Advances in Design of Low Cost Film Concentrator and Low Pressure Free Piston Stirling Engines for Solar Power

    NASA Technical Reports Server (NTRS)

    Kleinwaechter, J.; Kleinwaechter, H.; Beale, W.

    1984-01-01

    The free piston Stirling-linear alternator was shown to be scalable to power levels of tens of kilowatts in a form which is simple, efficient, long lived and relatively inexpensive. It avoids entirely the vexing problem of high pressure shaft, and its control requirements are not severe nor do they represent a significant threat to durability. Linear alternators have demonstrated high efficiency and moderate weight, and are capable of delivering 3 phase power from single machines without great increases of cost or complexity. There remains no apparent impediments to the commercial exploitation of the free piston engine for solar electric power generation.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. The base engine for solar Stirling power

    NASA Astrophysics Data System (ADS)

    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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Lightweight Radiators Being Developed or Advanced Stirling Radioisotope Power Systems

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    The thermodynamic heat-to-electric power conversion efficiency of Stirling systems is 3 to 5 times higher than that of thermoelectric converters. Hence for unmanned deep space probes, Stirling advanced radioisotope power systems (ARPS) could deliver up to 5 times as much power as radioisotope thermoelectric generators for the same amount of radioisotope, or they could require one-third to one-fifth as much isotope inventory for the same power output. However, Stirling power systems reject unconverted heat at much lower temperatures than radioisotope thermoelectric generators. Normally, this requires larger and heavier heat-rejection subsystems because of the greater radiator areas, which are proportional to the first power of the heat rejected and the fourth power of the absolute heat-rejection temperature, as specified by the Stefan-Boltzmann radiation heat transfer law. The development of directly coupled disk radiators using very high conductivity encapsulated thermopyrolitic graphite materials represents a significant advance in Stirling ARPS space heat-rejection subsystem technology. A conceptual Stirling ARPS with two engines coupled to a radioisotope general-purpose heat source (GPHS) is shown in the illustration.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Advanced Technology Development for Stirling Convertors

    NASA Astrophysics Data System (ADS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2004-02-01

    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 third-generation 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.

  2. 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.

  3. 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.

  4. 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.

  5. Experimental assessment of advanced Stirling component concepts

    NASA Technical Reports Server (NTRS)

    Ziph, B.

    1985-01-01

    The results of an experimental assessment of some advanced Stirling engine component concepts are presented. High performance piston rings, reciprocating oil scrapers and heat pipes with getters and with mechanical couplings were tested. The tests yielded the following results: (1) Bonded, split, pumping piston rings, in preliminary testing, proved a promising concept, exhibiting low leakage and friction losses. Solid piston rings proved impractical in view of their sensitivity to the operating temperature; (2) A babbit oil scraper in a compliant housing performed well in atmospheric endurance testing. In pressurized tests the scraper did not perform well as a containment seal. The latter tests suggest modifications which may adapt Ti successfully to that application; and (3) Heat pipe endurance tests indicated the adequacy of simple, inexpensive fabrication and filling procedures. Getters were provided to increase the tolerance of the heat pipes to the presence of air and commercially available couplings were demonstrated to be suitable for heat pipe application. In addition to the above tests, the program also included a design effort for a split shaft applicable to a swashplate driven engine with a pressurized crank-case. The design is aimed, and does accomplish, an increase in component life to more than 10,000 hours.

  6. Two piston V-type Stirling engine

    SciTech Connect

    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.

  7. Piston rod seal for a Stirling engine

    SciTech Connect

    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.

  8. 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.

  9. Automotive Stirling reference engine design report

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The reference Stirling engine system is described which provides the best possible fuel economy while meeting or exceeding all other program objectives. The system was designed to meet the requirements of a 1984 Pontiac Phoenix (X-body). This design utilizes all new technology that can reasonably be expected to be developed by 1984 and that is judged to provide significant improvement, relative to development risk and cost. Topics covered include: (1) external heat system; (2) hot engine system; (3) cold engine system; (4) engine drive system; (5) power control system and auxiliaries; (6) engine instalation; (7) optimization and vehicle simulation; (8) engine materials; and (9) production cost analysis.

  10. 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.

  11. 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.

  12. Diaphragm Stirling engine heat-actuated heat pump development

    NASA Astrophysics Data System (ADS)

    Ackermann, R. A.; Swenson, P.

    A power module, consisting of a free displacer, resonant Stirling engine, hydraulic transmission, and resonant Rankine refrigerant (F-22) compressor, embodies several innovative concepts in free-piston Stirling engine heat pump design that will advance the state of the art of this technology. Progress is reported in three areas of the program. A compressor/engine matching analysis and a stability analysis show that the power module, which is representative of a two-degree-of-freedom resonant system, can operate stably over the full range of heat pump conditions. A compressor design evolved that has met criteria for performance and cost. Tests employing a hydraulic simulator test rig show that the transmission losses are less than had been predicted, and that properly designed and fabricated diaphragms can attain long life.

  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. Advanced 80 We Stirling Convertor Development Progress

    NASA Astrophysics Data System (ADS)

    Wood, J. Gary; Carroll, Cliff; Penswick, L. B.

    2005-02-01

    This paper presents progress on the Advanced Stirling Convertor (ASC) being developed by Sunpower and Boeing/Rocketdyne under NASA NRA funding. The ASC will use a high temperature heater head to allow for operation at 850 °C. The ASC is projected to have an efficiency approaching 40% (AC electrical out/ heat in) when operating at a temperature ratio of 3.0, and to have a convertor specific power of 90 We/kg (AC). An early developmental unit, the Frequency Test Bed (FTB) convertor, has already demonstrated 36% efficiency (based on AC electrical out) at this temperature ratio. The ASC is being developed for potential use in advanced radioisotope space power systems. The increased efficiency of this Stirling convertor compared to RTGs, would reduce the required amount of Plutonium fuel by a factor of approximately 5.

  15. 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.

  16. 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.)

  17. Automotive Stirling engine system component review

    NASA Technical Reports Server (NTRS)

    Hindes, Chip; Stotts, Robert

    1987-01-01

    The design and testing of the power and combustion control system for the basic Stirling engine, Mod II, are examined. The power control system is concerned with transparent operation, and the Mod II uses engine working gas pressure variation to control the power output of the engine. The main components of the power control system, the power control valve, the pump-down system, and the hydrogen stable system, are described. The combustion control system consists of a combustion air supply system and an air/fuel ratio control system, and the system is to maintain constant heater head temperature, and to maximize combustion efficiency and to minimize exhaust emissions.

  18. 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.

  19. Automotive Stirling Engine Development Program

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

    Program status and plans are discussed for component and technology development; reference engine system design, the upgraded Mod 1 engine; industry test and evaluation; and product assurance. Four current Mod 1 engines reached a total of 2523 operational hours, while two upgraded engines accumulated 166 hours.

  20. 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.

  1. Design of hydraulic output Stirling engine

    NASA Technical Reports Server (NTRS)

    Toscano, W. M.; Harvey, A. C.; Lee, K.

    1983-01-01

    A hydraulic output system for the RE-1000 free piston stirling engine (FPSE) was designed. The hydraulic output system can be readily integrated with the existing hot section of RE-1000 FPSE. The system has two simply supported diaphragms which separate the engine gas from the hydraulic fluid, a dynamic balance mechanism, and a novel, null center band hydraulic pump. The diaphragms are designed to endure more than 10 billion cycles, and to withstand the differential pressure load as high as 14 MPa. The projected thermodynamic performance of the hydraulic output version of RE-1000 FPSE is 1.87 kW at 29/7 percent brake efficiency.

  2. Double acting stirling engine phase control

    DOEpatents

    Berchowitz, David M.

    1983-01-01

    A mechanical device for effecting a phase change between the expansion and compression volumes of a double-acting Stirling engine uses helical elements which produce opposite rotation of a pair of crankpins when a control rod is moved, so the phase between two pairs of pistons is changed by +.psi. and the phase between the other two pairs of pistons is changed by -.psi.. The phase can change beyond .psi.=90.degree. at which regenerative braking and then reversal of engine rotation occurs.

  3. Low temperature differential thermoacoustic Stirling engine

    NASA Astrophysics Data System (ADS)

    Biwa, Tetsushi; Hasegawa, Daichi; Yazaki, Taichi

    2010-07-01

    To what extent can we lower the critical temperature ratio (CTR) necessary to start a thermoacoustic engine? We present an experimental method for predicting the CTR before the temperature ratio arrives at it using quality factor measurements. Based on the experimental quality factors, we tried to decrease the CTR of a thermoacoustic Stirling engine consisting of a looped tube and a branch resonator. Installation of the multiple regenerators at suitable positions can markedly enhance acoustic power production while overcoming energy dissipation. Results show that the CTR is decreased from 1.76 to 1.19 using five differentially heated regenerators.

  4. Choosing An Alloy For Automotive Stirling Engines

    NASA Technical Reports Server (NTRS)

    Stephens, Joseph R.

    1988-01-01

    Report describes study of chemical compositions and microstructures of alloys for automotive Stirling engines. Engines offer advantages of high efficiency, low pollution, low noise, and ability to use variety of fuels. Twenty alloys evaluated for resistance to corrosion permeation by hydrogen, and high temperature. Iron-based alloys considered primary candidates because of low cost. Nickel-based alloys second choice in case suitable iron-based alloy could not be found. Cobalt-based alloy included for comparison but not candidate, because it is expensive strategic material.

  5. Development of a Thermoacoustic Stirling Engine Technology Demonstrator

    NASA Astrophysics Data System (ADS)

    Reissner, Alexander; Gerger, Joachim; Hummel, Stefan; Reißig, Jannis; Pawelke, Roland

    2014-08-01

    Waste heat is a primary source of energy loss in many aerospace and terrestrial applications. FOTEC, an Austrian Research Company located in Wiener Neustadt, is presently developing a micro power converter, promising high efficiencies even for small- scale applications. The converter is based on an innovative thermoacoustic stirling engine concept without any moving parts. Such a maintenance-free engine system would be particularly suitable for advanced space power systems (radioisotope, waste heat) or even within the scope of terrestrial energy harvesting. This paper will summarizes the status of our ongoing efforts on this micro power converter technology.

  6. Overview of NASA Lewis Research Center free-piston Stirling engine activities

    SciTech Connect

    Slaby, J.G.

    1984-01-01

    An overview of the National Aeronautics and Space Administration (NASA) Lewis Research Center (LeRC) free-piston Stirling engine activities is presented. These include (1) a generic free-piston Stirling technology project being conducted to develop technologies generic to both space power and terrestrial heat pump applications in a cooperative, cost-shared effort with the Department of Energy (DOE)/Oak Ridge National Laboratory (ORNL); and (2) a free-piston Stirling space power technology feasibility demonstration project being conducted in support of the Defense Advanced Research Projects Agency (DARPA), DOE, NASA, SP-100 project. The generic technology effort includes extensive parametric testing of a 1 kW free-piston Stirling engine (RE-1000), development of a free-piston Stirling performance computer code, design and fabrication under contract of a hydraulic output modification for RE-1000 engine tests, and a 1000-hour endurance test, under contract, of a 3 kWe free-piston Stirling/alternator engine. The newly initiated space power technology feasibility demonstration effort addresses the capability of scaling a free-piston Stirling/alternator system to about 25 kWe; developing thermodynamic cycle efficiency greater than or equal to 70 percent of Carnot at temperature ratios in the order of 1.5 to 2.0; achieving a power conversion unit specific weight of 6 kg/kWe; operating with noncontacting gas bearings; and dynamically balancing the system. Planned engine and component design and test efforts are described.

  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. Structural Dynamics Testing of Advanced Stirling Convertor Components

    NASA Technical Reports Server (NTRS)

    Oriti, Sal; Williams, Zach

    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.

  9. Externally heated valve engine -- An alternative to the Stirling engine

    SciTech Connect

    Kazimierski, Z.; Brzeski, L.

    1996-12-31

    A new concept of the Externally Heated Valve (EHV) engine is presented. The principle of the engine operation is described in the introduction to the paper. Heat delivered to the working medium (air) in the heater, or several heaters working commutatively, can come from a combustion chamber or other heat generator such as nuclear reactors or solar collectors. The engine construction is original entirely different from the well-known Stirling engine. New results of the EHV engine computer modeling are presented. This is connected with a new kind of the annular heater applied to the EHV engine. A whirl motion inside the heater is caused to ensure the proper condition of the heat exchanger during the whole engine cycle. Three heaters working commutatively have been considered in this model. Comparisons between the power and efficiency of the Stirling engine and EHV engine have been performed for the same engine capacity, rotational frequency, maximum and minimum temperatures of the working gas and for the same mean pressures of both the engine cycles. The power of the EHV engine is in this case over three times higher than the Stirling engine power, while the efficiency of both the engines is almost the same.

  10. 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.

  11. 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.

  12. Congeneration system with a Stirling engine

    SciTech Connect

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

    1991-12-24

    This patent describes a cogeneration system for producing process heat for useful purposes and electric energy. It comprises an electric generator; a Stirling cycle engine having an output shaft operatively coupled to the generator for driving the generator, the engine including at least one internal fuel combustor; means for circulating a cooling liquid about the generator and engine to extract heat therefrom; an exhaust system coupled with the engine for exhausting combustion gases from the engine, the exhaust system including a condensing heat exchanger for cooling the combustion gases below the condensing, temperature of the water vapor in the exhaust gases; means for directing the cooling liquid around the condensing heat exchanger to extract heat therefrom and heat the liquid; and means for directing the cooling liquid for useful purposes.

  13. Initial testing of a variable-stroke Stirling engine

    SciTech Connect

    Thieme, L.G.

    1985-02-01

    In support of the US Department of Energy's Stirling Engine Highway Vehicle Systems Program, NASA Lewis Research Center is evaluating variable-stroke control for Stirling engines. The engine being tested is the Advenco Stirling engine; this engine was manufactured by Philips Research Laboratories of the Netherlands and uses a variable-angle swash-plate drive to achieve variable stroke operation. This report describes the engine, presents initial steady-state test data taken at Lewis, and describes a major drive system failure and subsequent modifications. Computer simulation results are presented to show potential part-load efficiency gains with variable-stroke control.

  14. Initial testing of a variable-stroke Stirling engine

    NASA Technical Reports Server (NTRS)

    Thieme, L. G.

    1985-01-01

    In support of the U.S. Department of Energy's Stirling Engine Highway Vehicle Systems Program, NASA Lewis Research Center is evaluating variable-stroke control for Stirling engines. The engine being tested is the Advenco Stirling engine; this engine was manufactured by Philips Research Laboratories of the Netherlands and uses a variable-angle swash-plate drive to achieve variable stroke operation. The engine is described, initial steady-state test data taken at Lewis are presented, a major drive system failure and subsequent modifications are described. Computer simulation results are presented to show potential part-load efficiency gains with variable-stroke control.

  15. 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.

  16. 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.

  17. Automotive Stirling Engine Development Program

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    Development test activities on Mod I engines directed toward evaluating technologies for potential inclusion in the Mod II engine are summarized. Activities covered include: test of a 12-tube combustion gas recirculation combustor; manufacture and flow-distribution test of a two-manifold annular heater head; piston rod/piston base joint; single-solid piston rings; and a digital air/fuel concept. Also summarized are results of a formal assessment of candidate technologies for the Mod II engine, and preliminary design work for the Mod II. The overall program philosophy weight is outlined, and data and test results are presented.

  18. 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.

  19. Stability analysis of free piston Stirling engines

    NASA Astrophysics Data System (ADS)

    Bégot, Sylvie; Layes, Guillaume; Lanzetta, François; Nika, Philippe

    2013-03-01

    This paper presents a stability analysis of a free piston Stirling engine. The model and the detailed calculation of pressures losses are exposed. Stability of the machine is studied by the observation of the eigenvalues of the model matrix. Model validation based on the comparison with NASA experimental results is described. The influence of operational and construction parameters on performance and stability issues is exposed. The results show that most parameters that are beneficial for machine power seem to induce irregular mechanical characteristics with load, suggesting that self-sustained oscillations could be difficult to maintain and control.

  20. The power formula for atmospheric Stirling engines

    NASA Astrophysics Data System (ADS)

    Kolin, Ivo; Lista, Paolo; Naso, Vincenzo

    A new proposed formula allows the evaluation of the indicated power of an atmospheric Stirling engine by means of minimum working fluid volume, mean arithmetical pressure difference and correction factors for dead space and compression ratio, grounded on the simplest geometrical and design characteristics. The practical example given in this paper presents the comparison among the Beale formula and other similar equations, developed by other authors, showing various degrees of accuracy. Closer approximation has been reached by the proposed formula in comparison with other expressions.

  1. Loss terms in free-piston Stirling engine models

    NASA Technical Reports Server (NTRS)

    Gordon, Lloyd B.

    1992-01-01

    Various models for free piston Stirling engines are reviewed. Initial models were developed primarily for design purposes and to predict operating parameters, especially efficiency. More recently, however, such models have been used to predict engine stability. Free piston Stirling engines have no kinematic constraints and stability may not only be sensitive to the load, but also to various nonlinear loss and spring constraints. The present understanding is reviewed of various loss mechanisms for free piston Stirling engines and how they have been incorporated into engine models is discussed.

  2. Potential impacts of Brayton and Stirling cycle engines

    NASA Technical Reports Server (NTRS)

    Heft, R. C.

    1980-01-01

    Two engine technologies (Brayton cycle and Stirling cycle) are examined for their potential economic impact and fuel utilization. An economic analysis of the expected response of buyers to the attributes of the alternative engines was performed. Hedonic coefficients for vehicle fuel efficiency, performance and size were estimated for domestic cars based upon historical data. The marketplace value of the fuel efficiency enhancement provided by Brayton or Stirling engines was estimated. Under the assumptions of 10 years for plant conversions and 1990 and 1995 as the introduction data for turbine and Stirling engines respectively, the comparative fuel savings and present value of the future savings in fuel costs were estimated.

  3. Stirling cycle engine and refrigeration systems

    NASA Technical Reports Server (NTRS)

    Higa, W. H. (Inventor)

    1976-01-01

    A Stirling cycle heat engine is disclosed in which displacer motion is controlled as a function of the working fluid pressure P sub 1 and a substantially constant pressure P sub 0. The heat engine includes an auxiliary chamber at the constant pressure P sub 0. An end surface of a displacer piston is disposed in the auxiliary chamber. During the compression portion of the engine cycle when P sub 1 rises above P sub 0 the displacer forces the working fluid to pass from the cold chamber to the hot chamber of the engine. During the expansion portion of the engine cycle the heated working fluid in the hot chamber does work by pushing down on the engine's drive piston. As the working fluid pressure P sub 1 drops below P sub 0 the displacer forces most of the working fluid in the hot chamber to pass through the regenerator to the cold chamber. The engine is easily combinable with a refrigeration section to provide a refrigeration system in which the engine's single drive piston serves both the engine and the refrigeration section.

  4. Stirling engine alternatives for the terrestrial solar application

    NASA Technical Reports Server (NTRS)

    Stearns, J.

    1985-01-01

    The first phase of the present study of Stirling engine alternatives for solar thermal-electric generation has been completed. Development risk levels are considered to be high for all engines evaluated. Free-piston type and Ringbom-type Stirling engine-alternators are not yet developed for the 25 to 50-kW electrical power range, although smaller machines have demonstrated the inherent robustness of the machines. Kinematic-type Stirling engines are presently achieving a 3500 hr lifetime or longer on critical components, and lifetime must still be further extended for the solar application. Operational and technical characteristics of all types of Stirling engines have been reviewed with engine developers. Technical work of merit in progress in each engine development organization should be recognized and supported in an appropriate manner.

  5. Overview of the 1985 NASA Lewis Research Center SP-100 free-piston Stirling engine activities

    SciTech Connect

    Slaby, J.G.

    1985-01-01

    An overview of the 1985 (NASA) Lewis Research Center free-piston Stirling engine activities in support of the SP-100 Program is presented. The SP-100 program is being conducted in support of the Department of Advanced Research Projects Agency (DARPA) and the Department of Energy (DOE), and NASA. This effort is keyed on the design, fabrication, assembly, and testing of a 25 kW(e) Stirling space-power technology-feasibility demonstrator engine. Another facet of the SP-100 project covers the status of a 9000-h goal endurance test conducted on a 2 kW(e) free-piston Stirling/linear alternator system employing hydrostatic gas bearings. Dynamic balancing of the RE-1000 engine (a 1 kW(e) free-piston Stirling engine) using a passive dynamic absorber is discussed, along with the results of a parametric study showing the relationships of Stirling power converter specific weight and efficiency as functions of Stirling engine heater to cooler temperature ratio. Planned tests are described covering a hydrodynamic gas bearing concept for potential SP-100 application.

  6. 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.

  7. 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.

  8. Commissioning and Performance Analysis of WhisperGen Stirling Engine

    NASA Astrophysics Data System (ADS)

    Pradip, Prashant Kaliram

    Stirling engine based cogeneration systems have potential to reduce energy consumption and greenhouse gas emission, due to their high cogeneration efficiency and emission control due to steady external combustion. To date, most studies on this unit have focused on performance based on both experimentation and computer models, and lack experimental data for diversified operating ranges. This thesis starts with the commissioning of a WhisperGen Stirling engine with components and instrumentation to evaluate power and thermal performance of the system. Next, a parametric study on primary engine variables, including air, diesel, and coolant flowrate and temperature were carried out to further understand their effect on engine power and efficiency. Then, this trend was validated with the thermodynamic model developed for the energy analysis of a Stirling cycle. Finally, the energy balance of the Stirling engine was compared without and with heat recovery from the engine block and the combustion chamber exhaust.

  9. Creep rupture behavior of Stirling engine materials

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    The automotive Stirling engine, being investigated jointly by the Department of Energy and NASA Lewis as an alternate to the internal combustion engine, uses high-pressure hydrogen as the working fluid. The long-term effects of hydrogen on the high temperature strength properties of materials is relatively unknown. This is especially true for the newly developed low-cost iron base alloy NASAUT 4G-A1. This iron-base alloy when tested in air has creep-rupture strengths in the directionally solidified condition comparable to the cobalt base alloy HS-31. The equiaxed (investment cast) NASAUT 4G-A1 has superior creep-rupture to the equiaxed iron-base alloy XF-818 both in air and 15 MPa hydrogen.

  10. Linear hydraulic drive system for a Stirling engine

    DOEpatents

    Walsh, Michael M.

    1984-02-21

    A hydraulic drive system operating from the periodic pressure wave produced by a Stirling engine along a first axis thereof and effecting transfer of power from the Stirling engine to a load apparatus therefor and wherein the movable, or working member of the load apparatus is reciprocatingly driven along an axis substantially at right angles to the first axis to achieve an arrangement of a Stirling engine and load apparatus assembly which is much shorter and the components of the load apparatus more readily accessible.

  11. 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.

  12. 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

  13. 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.

  14. Stirling engine control mechanism and method

    DOEpatents

    Dineen, John J.

    1983-01-01

    A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion.

  15. Initial experiments with a laser driven Stirling engine

    NASA Technical Reports Server (NTRS)

    Byer, R. L.

    1976-01-01

    Operation of a Beale free piston Stirling engine with a 40-W CO2 laser is described. Advantages of such a system include: closed-cycle operation, long life, inexpensive construction, and size scalability to 100 MW.

  16. 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.

  17. 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.

  18. 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.

  19. Base technology Stirling engine military applications assessment. Final technical report, 1 June 30-September 1983

    SciTech Connect

    Daley, J.G.

    1983-10-01

    The design of an advanced Stirling engine is considered for potential use in Air Force mobile electric power generator sets. The prospects for acceptable reliability appears good due to new approaches to recognized Stirling problem areas; sealing, heater head and control. The present design appears suitable for a 30kW set, but Air Force needs would be best suited by development of a 60kW unit. Standardization would be facilitated by using the 60kW Stirling engine and associated auxiliaries in a 30kW set. Final design drawings have been completed in the 30kW engine but construction and tests are required to establish that both design criteria for the engine and mobile power requirements are met. Originator-supplied keywords include: Heat pipe, and Combustor control.

  20. 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.

  1. A Stirling engine for use with lower quality fuels

    NASA Astrophysics Data System (ADS)

    Paul, Christopher J.

    There is increasing interest in using renewable fuels from biomass or alternative fuels such as municipal waste to reduce the need for fossil based fuels. Due to the lower heating values and higher levels of impurities, small scale electricity generation is more problematic. Currently, there are not many technologically mature options for small scale electricity generation using lower quality fuels. Even though there are few manufacturers of Stirling engines, the history of their development for two centuries offers significant guidance in developing a viable small scale generator set using lower quality fuels. The history, development, and modeling of Stirling engines were reviewed to identify possible model and engine configurations. A Stirling engine model based on the finite volume, ideal adiabatic model was developed. Flow dissipation losses are shown to need correcting as they increase significantly at low mean engine pressure and high engine speed. The complete engine including external components was developed. A simple yet effective method of evaluating the external heat transfer to the Stirling engine was created that can be used with any second order Stirling engine model. A derivative of the General Motors Ground Power Unit 3 was designed. By significantly increasing heater, cooler and regenerator size at the expense of increased dead volume, and adding a combustion gas recirculation, a generator set with good efficiency was designed.

  2. Initial characterization of a modular heat exchanger with an integral heat pipe. [for Stirling space engine

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    1989-01-01

    As part of the Civil Space Technology Initiative (CSTI) Advanced Technology program, a conceptual design of the Stirling space engibe (SSE) was generated to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The free-piston Stirling engine (FPSE) was chosen as the growth option in the CSTI program. An existing FPSE was modified as a test bed for a modular heat exchanger evaluation. Evaluation of the individual heat pipes before installation in the engine is described.

  3. Integrated two-cylinder liquid piston Stirling engine

    NASA Astrophysics Data System (ADS)

    Yang, Ning; Rickard, Robert; Pluckter, Kevin; Sulchek, Todd

    2014-10-01

    Heat engines utilizing the Stirling cycle may run on low temperature differentials with the capacity to function at high efficiency due to their near-reversible operation. However, current approaches to building Stirling engines are laborious and costly. Typically the components are assembled by hand and additional components require a corresponding increase in manufacturing complexity, akin to electronics before the integrated circuit. We present a simple and integrated approach to fabricating Stirling engines with precisely designed cylinders. We utilize computer aided design and one-step, planar machining to form all components of the engine. The engine utilizes liquid pistons and displacers to harness useful work from heat absorption and rejection. As a proof of principle of the integrated design, a two-cylinder engine is produced and characterized and liquid pumping is demonstrated.

  4. Integrated two-cylinder liquid piston Stirling engine

    SciTech Connect

    Yang, Ning; Rickard, Robert; Pluckter, Kevin; Sulchek, Todd

    2014-10-06

    Heat engines utilizing the Stirling cycle may run on low temperature differentials with the capacity to function at high efficiency due to their near-reversible operation. However, current approaches to building Stirling engines are laborious and costly. Typically the components are assembled by hand and additional components require a corresponding increase in manufacturing complexity, akin to electronics before the integrated circuit. We present a simple and integrated approach to fabricating Stirling engines with precisely designed cylinders. We utilize computer aided design and one-step, planar machining to form all components of the engine. The engine utilizes liquid pistons and displacers to harness useful work from heat absorption and rejection. As a proof of principle of the integrated design, a two-cylinder engine is produced and characterized and liquid pumping is demonstrated.

  5. Component improvement of free-piston Stirling engine key technology for space power

    NASA Technical Reports Server (NTRS)

    Alger, Donald L.

    1988-01-01

    The successful performance of the 25 kW Space Power Demonstrator (SPD) engine during an extensive testing period has provided a baseline of free piston Stirling engine technology from which future space Stirling engines may evolve. Much of the success of the engine was due to the initial careful selection of engine materials, fabrication and joining processes, and inspection procedures. Resolution of the few SPD engine problem areas that did occur has resulted in the technological advancement of certain key free piston Stirling engine components. Derivation of two half-SPD, single piston engines from the axially opposed piston SPD engine, designated as Space Power Research (SPR) engines, has made possible the continued improvement of these engine components. The two SPR engines serve as test bed engines for testing of engine components. Some important fabrication and joining processes are reviewed. Also, some component deficiencies that were discovered during SPD engine testing are described and approaches that were taken to correct these deficiencies are discussed. Potential component design modifications, based upon the SPD and SPR engine testing, are also reported.

  6. Development free-piston Stirling test-bed engine

    NASA Astrophysics Data System (ADS)

    Dochat, G. R.; Vitale, N. G.; Moynihan, T. M.

    The free-piston Stirling Technology Demonstrator Engine (TDE) designed and instrumented to provide data to aid in understanding free-piston Stirling engine operation and performance, is described. It is noted that the system includes instrumentation to measure the internal thermodynamic operation and to permit calculation of system power flows. Near-term testing of the engine will assess three mechanisms for engine loss. It is pointed out that recent testing has demonstrated that the power and efficiency are strong functions of heater head temperature. A maximum power output of 1,800 watts and a thermodynamic efficiency of 30% have been demonstrated at 450 C and 40 bar.

  7. Baseline performance of the GPU 3 Stirling engine

    NASA Technical Reports Server (NTRS)

    Thieme, L. G.; Tew, R. C., Jr.

    1978-01-01

    A 10 horsepower single-cylinder rhombic-drive Stirling engine was converted to a research configuration to obtain data for validation of Stirling computer simulations. The engine was originally built by General Motors Research Laboratories for the U.S. Army in 1965 as part of a 3 kW engine-generator set, designated the GHU 3 (Ground Power Unit). This report presents test results for a range of heater gas temperatures, mean compression-space pressures, and engine speeds with both helium and hydrogen as the working fluids. Also shown are initial data comparisons with computer simulation predictions.

  8. Automotive Stirling Engine Development Program. RESD summary report

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design of reference Stirling engine system as well as the engine auxiliaries and controls is described. Manufacturing costs in production quantity are also presented. Engine system performance predictions are discussed and vehicle integration is developed, along with projected fuel economy levels.

  9. Improving Power Density of Free-Piston Stirling Engines

    NASA Technical Reports Server (NTRS)

    Briggs, Maxwell H.; Prahl, Joseph; Loparo, Kenneth

    2016-01-01

    Analyses and experiments demonstrate the potential benefits of optimizing piston and displacer motion in a free piston Stirling Engine. Isothermal analysis shows the theoretical limits of power density improvement due to ideal motion in ideal Stirling engines. More realistic models based on nodal analysis show that ideal piston and displacer waveforms are not optimal, often producing less power than engines that use sinusoidal piston and displacer motion. Constrained optimization using nodal analysis predicts that Stirling engine power density can be increased by as much as 58 using optimized higher harmonic piston and displacer motion. An experiment is conducted in which an engine designed for sinusoidal motion is forced to operate with both second and third harmonics, resulting in a maximum piston power increase of 14. Analytical predictions are compared to experimental data showing close agreement with indirect thermodynamic power calculations, but poor agreement with direct electrical power measurements.

  10. Improving Power Density of Free-Piston Stirling Engines

    NASA Technical Reports Server (NTRS)

    Briggs, Maxwell H.; Prahl, Joseph M.; Loparo, Kenneth A.

    2016-01-01

    Analyses and experiments demonstrate the potential benefits of optimizing piston and displacer motion in a free-piston Stirling Engine. Isothermal analysis shows the theoretical limits of power density improvement due to ideal motion in ideal Stirling engines. More realistic models based on nodal analysis show that ideal piston and displacer waveforms are not optimal, often producing less power than engines that use sinusoidal piston and displacer motion. Constrained optimization using nodal analysis predicts that Stirling engine power density can be increased by as much as 58 percent using optimized higher harmonic piston and displacer motion. An experiment is conducted in which an engine designed for sinusoidal motion is forced to operate with both second and third harmonics, resulting in a piston power increase of as much as 14 percent. Analytical predictions are compared to experimental data and show close agreement with indirect thermodynamic power calculations, but poor agreement with direct electrical power measurements.

  11. Improving Free-Piston Stirling Engine Power Density

    NASA Technical Reports Server (NTRS)

    Briggs, Maxwell H.

    2016-01-01

    Analyses and experiments demonstrate the potential benefits of optimizing piston and displacer motion in a free piston Stirling Engine. Isothermal analysis shows the theoretical limits of power density improvement due to ideal motion in ideal Stirling engines. More realistic models based on nodal analysis show that ideal piston and displacer waveforms are not optimal, often producing less power than engines that use sinusoidal piston and displacer motion. Constrained optimization using nodal analysis predicts that Stirling engine power density can be increased by as much as 58% using optimized higher harmonic piston and displacer motion. An experiment is conducted in which an engine designed for sinusoidal motion is forced to operate with both second and third harmonics, resulting in a maximum piston power increase of 14%. Analytical predictions are compared to experimental data showing close agreement with indirect thermodynamic power calculations, but poor agreement with direct electrical power measurements.

  12. 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.

  13. Micro-cogeneration units based on Stirling engine for heating and their real operation

    NASA Astrophysics Data System (ADS)

    Čierny, Jaroslav; Patsch, Marek

    2014-08-01

    This article was deal with micro-cogeneration units based on Stirling engine. We watched problematic of real working Stirling engine. The article also contain hookup of unit constructed at University of Zilina.

  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 engine research at national and university laboratories in Japan

    SciTech Connect

    Hane, G.J.; Hutchinson, R.A.

    1987-09-01

    Pacific Northwest Laboratory (PNL) reviewed research projects that are related to the development of Stirling engines and that are under way at Japanese national laboratories and universities. The research and development focused on component rather than on whole engine development. PNL obtained the information from a literature review and interviews conducted at the laboratories and universities. The universities have less equipment available and operate with smaller staffs for research than do the laboratories. In particular, the Mechanical Engineering Laboratory and the Aerospace Laboratory conduct high-quality component and fundamental work. Despite having less equipment, some of the researchers at the universities conduct high-quality fundamental research. As is typical in Japan, several of the university professors are very active in consulting and advisory capacities to companies engaged in Stirling engine development, and also with government and association advisory and technical committees. Contacts with these professors and selective examination of their research are good ways to keep abreast of Japanese Stirling developments.

  17. Solar heat pipe testing of the Stirling thermal motors 4-120 Stirling engine

    SciTech Connect

    Andraka, C.E.; Rawlinson, K.S.; Moss, T.A.; Adkins, D.R.; Moreno, J.B.; Gallup, D.R.; Cordeiro, P.G.; Johansson, S.

    1996-07-01

    Stirling-cycle engines have been identified as a promising technology for the conversion of concentrated solar energy into usable electrical power. A 25kW electric system takes advantage of existing Stirling-cycle engines and existing parabolic concentrator designs. In previous work, the concentrated sunlight impinged directly on the heater head tubes of the Stirling Thermal Motors (STM) 4-120 engine. A Sandia-designed felt-metal-wick heat pipe receiver was fitted to the STM 4-120 engine for on-sun testing on Sandia`s Test Bed Solar Concentrator. The heat pipe uses sodium metal as an intermediate two-phase heat transfer fluid. The receiver replaces the directly-illuminated heater head previously tested. The heat pipe receiver provides heat isothermally to the engine, and the heater head tube length is reduced, both resulting in improved engine performance. The receiver also has less thermal losses than the tube receiver. The heat pipe receiver design is based on Sandia`s second-generation felt-wick heat pipe receiver. This paper presents the interface design, and compares the heat pipe/engine test results to those of the directly-illuminated receiver/engine package.

  18. Insoluble coatings for Stirling engine heat pipe condenser surfaces

    NASA Technical Reports Server (NTRS)

    Dussinger, Peter M.

    1993-01-01

    The work done by Thermacore, Inc., Lancaster, Pennsylvania, for the Phase 1, 1992 SBIR National Aeronautics and Space Administration Contract, 'Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces' is described. The work was performed between January 1992 and July 1992. Stirling heat engines are being developed for electrical power generation use on manned and unmanned earth orbital and planetary missions. Dish Stirling solar systems and nuclear reactor Stirling systems are two of the most promising applications of the Stirling engine electrical power generation technology. The sources of thermal energy used to drive the Stirling engine typically are non-uniform in temperature and heat flux. Liquid metal heat pipe receivers are used as thermal transformers and isothermalizers to deliver the thermal energy at a uniform high temperature to the heat input section of the Stirling engine. The use of a heat pipe receiver greatly enhances system efficiency and potential life span. One issue that is raised during the design phase of heat pipe receivers is the potential solubility corrosion of the Stirling engine heat input section by the liquid metal working fluid. This Phase 1 effort initiated a program to evaluate and demonstrate coatings, applied to nickel based Stirling engine heater head materials, that are practically 'insoluble' in sodium, potassium, and NaK. This program initiated a study of nickel aluminide as a coating and developed and demonstrated a heat pipe test vehicle that can be used to test candidate materials and coatings. Nickel 200 and nickel aluminide coated Nickel 200 were tested for 1000 hours at 800 C at a condensation heat flux of 25 W/sq cm. Subsequent analyses of the samples showed no visible sign of solubility corrosion of either coated or uncoated samples. The analysis technique, photomicrographs at 200X, has a resolution of better than 2.5 microns (.0001 in). The results indicate that the heat pipe environment is not directly

  19. Insoluble coatings for Stirling engine heat pipe condenser surfaces

    NASA Astrophysics Data System (ADS)

    Dussinger, Peter M.

    1993-09-01

    The work done by Thermacore, Inc., Lancaster, Pennsylvania, for the Phase 1, 1992 SBIR National Aeronautics and Space Administration Contract, 'Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces' is described. The work was performed between January 1992 and July 1992. Stirling heat engines are being developed for electrical power generation use on manned and unmanned earth orbital and planetary missions. Dish Stirling solar systems and nuclear reactor Stirling systems are two of the most promising applications of the Stirling engine electrical power generation technology. The sources of thermal energy used to drive the Stirling engine typically are non-uniform in temperature and heat flux. Liquid metal heat pipe receivers are used as thermal transformers and isothermalizers to deliver the thermal energy at a uniform high temperature to the heat input section of the Stirling engine. The use of a heat pipe receiver greatly enhances system efficiency and potential life span. One issue that is raised during the design phase of heat pipe receivers is the potential solubility corrosion of the Stirling engine heat input section by the liquid metal working fluid. This Phase 1 effort initiated a program to evaluate and demonstrate coatings, applied to nickel based Stirling engine heater head materials, that are practically 'insoluble' in sodium, potassium, and NaK. This program initiated a study of nickel aluminide as a coating and developed and demonstrated a heat pipe test vehicle that can be used to test candidate materials and coatings. Nickel 200 and nickel aluminide coated Nickel 200 were tested for 1000 hours at 800 C at a condensation heat flux of 25 W/sq cm. Subsequent analyses of the samples showed no visible sign of solubility corrosion of either coated or uncoated samples. The analysis technique, photomicrographs at 200X, has a resolution of better than 2.5 microns (.0001 in). The results indicate that the heat pipe environment is not directly

  20. A simple method of calculating Stirling engines for engine design optimization

    NASA Technical Reports Server (NTRS)

    Martini, W. R.

    1978-01-01

    A calculation method is presented for a rhombic drive Stirling engine with a tubular heater and cooler and a screen type regenerator. Generally the equations presented describe power generation and consumption and heat losses. It is the simplest type of analysis that takes into account the conflicting requirements inherent in Stirling engine design. The method itemizes the power and heat losses for intelligent engine optimization. The results of engine analysis of the GPU-3 Stirling engine are compared with more complicated engine analysis and with engine measurements.

  1. Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces

    NASA Technical Reports Server (NTRS)

    Dussinger, Peter M.; Lindemuth, James E.

    1997-01-01

    The principal objective of this Phase 2 SBIR program was to develop and demonstrate a practically insoluble coating for nickel-based superalloys for Stirling engine heat pipe applications. Specific technical objectives of the program were: (1) Determine the solubility corrosion rates for Nickel 200, Inconel 718, and Udimet 72OLI in a simulated Stirling engine heat pipe environment, (2) Develop coating processes and techniques for capillary groove and screen wick structures, (3) Evaluate the durability and solubility corrosion rates for capillary groove and screen wick structures coated with an insoluble coating in cylindrical heat pipes operating under Stirling engine conditions, and (4) Design and fabricate a coated full-scale, partial segment of the current Stirling engine heat pipe for the Stirling Space Power Convertor program. The work effort successfully demonstrated a two-step nickel aluminide coating process for groove wick structures and interior wall surfaces in contact with liquid metals; demonstrated a one-step nickel aluminide coating process for nickel screen wick structures; and developed and demonstrated a two-step aluminum-to-nickel aluminide coating process for nickel screen wick structures. In addition, the full-scale, partial segment was fabricated and the interior surfaces and wick structures were coated. The heat pipe was charged with sodium, processed, and scheduled to be life tested for up to ten years as a Phase 3 effort.

  2. 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.

  3. Non-heat pipe/P-40 Stirling engine

    NASA Technical Reports Server (NTRS)

    Haglund, R. A.

    1980-01-01

    The non-heat-pipe receiver/P-40 Stirling engine system design is described. A 25 kW direct-driven induction-type alternator will be mounted directly to the P-40 engine to produce to a 60 Hz, 115/230 volt output.

  4. Finite-time thermodynamic analysis of the Stirling engine

    SciTech Connect

    Ibrahim, O.M.; Ladas, H.G.

    1995-12-31

    This paper presents a finite-time thermodynamic analysis of the Stirling engine cycle. A lumped-parameter thermodynamic model is used to describe the dynamic behavior of the Stirling engine. The mathematical formulation of this model is based on mass and energy balances with associated heat transfer rate equations. These governing equations are formulated into a set of ordinary differential equations, which are then solved numerically to obtain the dynamic behavior of the Stirling engine. Close inspection of the governing equations reveals that the time to complete on cycle, {tau} and the engine time constant, {tau}{sub c} always appear together in a dimensionless ratio. This ratio, {tau}/{tau}{sub c}, is defined here as the Finite-Time Parameter, FTP. The effects of FTP upon power output and efficiency, are studied. The results show that there exists an optimum power output for a given engine design, based on engine speed and heat-transfer contact time. The results also provide an engineering evaluation procedure to improve the efficiency and power output of Stirling engines.

  5. Stirling engines. (Latest citations from the COMPENDEX database). Published Search

    SciTech Connect

    Not Available

    1992-12-01

    The bibliography contains citations concerning Stirling engine technology. Design, development, performance testing, and applications are discussed, including power generation, cryogenic cooling, solar power applications, and ground and marine vehicles. The citations also examine engine component design and material testing results. (Contains 250 citations and includes a subject term index and title list.)

  6. First phase testing of solar thermal engine at United Stirling

    NASA Technical Reports Server (NTRS)

    Percival, W.; Nelving, H. G.

    1981-01-01

    The objective of the program is to demonstrate that the Stirling engine is a practical efficient and reliable energy converter when integrated with a parabolic dish concentrator, and that it has the potential of being cost competitive with fossil fueled electric generating systems of today. The engine, with its receiver (solar heat exchanger), alternator and control system, is described.

  7. Comparison of conceptual designs for 25 kWe advanced Stirling conversion systems for dish electric applications

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1989-01-01

    The Advanced Stirling Conversion System (ASCS) Project is managed by NASA Lewis Research Center through a cooperative interagency agreement with DOE. Conceptual designs for the ASCS's were completed under parallel contracts in 1987 by Mechanical Technology Inc. (MTI) of Latham, NY, and Stirling Technology Company (STC) of Richland, WA. Each design features a free-piston Stirling engine, a liquid metal heat pipe receiver, and a means to provide about 25 kW of electric power to a utility grid while meeting DOE's long term performance and cost goals. An independent assessment showed that both designs are manufacturable and have the potential to easily meet DOE's long term cost goals.

  8. Comparison of conceptual designs for 25 kWe advanced Stirling conversion systems for dish electric application

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1989-01-01

    The Advanced Stirling Conversion System (ASCS) Project is managed by NASA Lewis Research Center through a cooperative interagency agreement with DOE. Conceptual designs for the ASCS's were completed under parallel contracts in 1987 by Mechanical Technology Inc. (MTI) of Latham, NY, and Stirling Technology Company (STC) of Richland, WA. Each design features a free-piston Stirling engine, a liquid metal heat pipe receiver, and a means to provide about 25 kW of electric power to a utility grid while meeting DOE's long term performance and cost goals. An independent assessment showed that both designs are manufacturable and have the potential to easily meet DOE's long term cost goals.

  9. An experimental free displacer back-to-back gamma type Stirling engine

    SciTech Connect

    Lazarides, Y.G.; Kilgour, D.B.; Lewis, K.L.; Rallis, C.J.

    1983-08-01

    A novel type of Stirling engine has been designed and is currently at an advanced manufacturing stage at the School of Mechanical Engineering at the University of the Witwatersrand. The engine offers the main advantage of eliminating many of the sealing problems usually associated with Stirling engines and in one of its final configurations, it consists of only two moving parts. This follows previous work on a rig that has been used for low speed testing of the concept (up to 3,5 Hz) and at temperatures of up to 573 K. The engine has been designed on a modular basis to enable full experimentation. The displacer block that includes the heaters, regenerators and coolers is located on top of a modified Petter compression ignition engine which is used to provide the volume variations.

  10. Advanced Small Free-Piston Stirling Convertors for Space Power Applications

    NASA Astrophysics Data System (ADS)

    Wood, J. Gary; Lane, Neill

    2004-02-01

    This paper reports on the current status of an advanced 35 We free-piston Stirling convertor currently being developed under NASA SBIR Phase II funding. Also described is a further advanced and higher performance ~80 watt free-piston convertor being developed by Sunpower and Boeing/Rocketdyne for NASA under NRA funding. Exceptional overall convertor (engine plus linear alternator) thermodynamic performance (greater than 50% of Carnot) with specific powers around 100 We /kg appear reasonable at these low power levels.

  11. Vanguard I solar parabolic dish-Stirling engine module. Final report, May 28, 1982-September 30, 1984

    SciTech Connect

    Washom, B.J.

    1984-09-30

    Advanco Corporation and the US Department of Energy entered into a cooperative agreement in May 1982 for the design, manufacture, and test of a 25-kWe solar parabolic dish module utilizing a Stirling engine power conversion unit. The product of the cooperative agreement is the Vanguard solar parabolic dish-Stirling engine module. It was designed, fabricated, and shop assembled in Los Angeles, California, and Malmoe, Sweden, and was then installed and tested at Rancho Mirage, California, in accordance with the agreement's specifications. The design features simple fabrication and assembly techniques, low cost, and high operating efficiency. The cover displays the Vanguard module operating on-sun. The concept combines the United Stirling AB (USAB) 4-95 Solar II Stirling engine, the Jet Propulsion Laboratory (JPL) developed mirror facets, the Rockwell/Advanco exocentric gimbal mechanism (EGM), the advanced USAB receiver, and a dry, integrated heat rejection system.

  12. Selection of stirling engine parameter and modes of joint operation with the Topaz II

    SciTech Connect

    Kirillov, E.Y.; Ogloblin, B.G.; Shalaev, A.I.

    1996-03-01

    In addition to a high-temperature thermionic conversion cycle, application of a low-temperature machine cycle, such as the Stirling engine, is being considered. To select the optimum mode for joint operation of the Topaz II system and Stirling engine, output electric parameters are obtained as a function of thermal power released in the TFE fuel cores. The hydraulic diagram used for joint operation of the Topaz II and the Stirling engine is considered. Requirements to hydraulic characteristics of the Stirling engine heat exchanges are formulated. Scope of necessary modifications to mount the Stirling Engine on the Topaz II is estimated. {copyright} {ital 1996 American Institute of Physics.}

  13. Comparison of Stirling engines for use with a 25-kW disk-electric conversion system

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.

    1987-01-01

    Heat engines were evaluated for terrestrial solar heat receivers. The Stirling Engine was identified as one of the most promising engines for terrestrial applications. The potential to meet the Department of Energy (DOE) goals for performance and cost can be met by the free-piston Stirling engine. NASA Lewis is providing technical management for an Advanced Stirling Conversion System (ASCS) through a cooperative interagency agreement with DOE. Parallel contracts were awarded for conceptual designs of an ASCS. Each design will feature a free-piston Stirling engine, a liquid-metal heat pipe receiver, and a means to provide about 25 kW of electric power to a utility grid while meeting long-term performance and goals. The Mechanical Technology, Ins. (MTI) design incorporates a linear alternator to directly convert the solar energy to electricity while the Stirling Technology Company (STC) generates electrical power indirectly by using a hydraulic output to a ground-bases hydraulic pump/motor coupled to a rotating alternator. Both designs use technology which can reasonably be expected to be available in the 1980's. The ASCS designs using a free-piston Stirling engine, a heat transport system, a receiver, and the methods of providing electricity to the utility grid will be discussed.

  14. Characteristics, finite element analysis, test description, and preliminary test results of the STM4-120 kinematic Stirling engine

    SciTech Connect

    Linker, K.L.; Rawlinson, K.S.; Smith, G.

    1991-10-01

    The Department of Energy's Solar Thermal Program has as one of its program elements the development and evaluation of conversion device technologies applicable to dish-electric systems. The primary research and development combines a conversion device (heat engine), solar receiver, and generator mounted at the focus of a parabolic dish concentrator. The Stirling-cycle heat engine was identified as the conversion device for dish-electric with the most potential for meeting the program's goals for efficiency, reliability, and installed cost. To advance the technology toward commercialization, Sandia National Laboratories has acquired a Stirling Thermal Motors, Inc., kinematic Stirling engine, STM4-120, for evaluation. The engine is being bench-tested at Sandia's Engine Test Facility and will be combined later with a solar receiver for on-sun evaluation. This report presents the engine characteristics, finite element analyses of critical engine components, test system layout, instrumentation, and preliminary performance results from the bench test.

  15. Active Vibration Reduction of the Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A Stirling Radioisotope Generator (SRG) could offer space missions a more efficient power system that uses one fourth of the nuclear fuel and decreases the thermal footprint compared to the current state of the art. The Stirling Cycle Technology Development (SCTD) Project is funded by the RPS Program to developing Stirling-based subsystems, including convertors and controller maturation efforts that have resulted in high fidelity hardware like the Advanced Stirling Radioisotope Generator (ASRG), Advanced Stirling Convertor (ASC), and ASC Controller Unit (ACU). The SCTD Project also performs research to develop less mature technologies with a wide variety of objectives, including increasing temperature capability to enable new environments, improving system reliability or fault tolerance, reducing mass or size, and developing advanced concepts that are mission enabling. Active vibration reduction systems (AVRS), or "balancers", have historically been developed and characterized to provide fault tolerance for generator designs that incorporate dual-opposed Stirling convertors or enable single convertor, or small RPS, missions. Balancers reduce the dynamic disturbance forces created by the power piston and displacer internal moving components of a single operating convertor to meet spacecraft requirements for induced disturbance force. To improve fault tolerance for dual-opposed configurations and enable single convertor configurations, a breadboard AVRS was implemented on the Advanced Stirling Convertor (ASC). The AVRS included a linear motor, a motor mount, and a closed-loop controller able to balance out the transmitted peak dynamic disturbance using acceleration feedback. Test objectives included quantifying power and mass penalty and reduction in transmitted force over a range of ASC

  16. Active Vibration Reduction of the Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A Stirling Radioisotope Generator (SRG) could offer space missions a more efficient power system that uses one fourth of the nuclear fuel and decreases the thermal footprint compared to the current state of the art. The Stirling Cycle Technology Development (SCTD) Project is funded by the RPS Program to developing Stirling-based subsystems, including convertors and controller maturation efforts that have resulted in high fidelity hardware like the Advanced Stirling Radioisotope Generator (ASRG), Advanced Stirling Convertor (ASC), and ASC Controller Unit (ACU). The SCTD Project also performs research to develop less mature technologies with a wide variety of objectives, including increasing temperature capability to enable new environments, improving system reliability or fault tolerance, reducing mass or size, and developing advanced concepts that are mission enabling. Active vibration reduction systems (AVRS), or "balancers", have historically been developed and characterized to provide fault tolerance for generator designs that incorporate dual-opposed Stirling convertors or enable single convertor, or small RPS, missions. Balancers reduce the dynamic disturbance forces created by the power piston and displacer internal moving components of a single operating convertor to meet spacecraft requirements for induced disturbance force. To improve fault tolerance for dual-opposed configurations and enable single convertor configurations, a breadboard AVRS was implemented on the Advanced Stirling Convertor (ASC). The AVRS included a linear motor, a motor mount, and a closed-loop controller able to balance out the transmitted peak dynamic disturbance using acceleration feedback. Test objectives included quantifying power and mass penalty and reduction in transmitted force over a range of ASC

  17. Automotive Stirling engine development program. [fuel economy assessment

    NASA Technical Reports Server (NTRS)

    Kitzner, E. W.

    1978-01-01

    The Ford/DOE automotive Stirling engine development program is directed towards establishing the technological and developmental base that would enable a decision on whether an engineering program should be directed at Stirling engine production. The fuel economy assessment aims to achieve, with a high degree of confidence, the ERDA proposal estimate of 20.6 MPG (gasoline) for a 4500 lb 1WC Stirling engine passenger car. The current M-H fuel economy projection for the 170 HP Stirling engine is 15.7 MPG. The confidence level for this projection is 32%. A confidence level of 29% is projected for a 22.1 MPG estimate. If all of the planned analyses and test work is accomplished at the end of the one year effort, and the projected improvements are substantiated, the confidence levels would rise to 59% for the 20.6 MPG projection and 54% for the 22.1 MPG projection. Progress achieved thus far during the fuel economy assessment is discussed.

  18. 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.

  19. RE-1000 free-piston Stirling engine update

    NASA Technical Reports Server (NTRS)

    Schreiber, J.

    1985-01-01

    A free piston Stirling engine was tested. The tests performed over the past several years on the single cylinder engine were designed to investigate the dynamics of a free piston Stirling engine. The data are intended to be used primarily for computer code validation. The tests designed to investigate the sensitivity of the engine performance to variations in working space pressure, heater and cooler temperatures, regenerator porosity, power piston mass and displacer dynamics were completed. In addition, some data were recorded with alternate working fluids. A novel resonant balance system for the engine was also tested. Some preliminary test results of the tests performed are presented along with an outline of future tests to be run with the engine coupled to a hydraulic output unit. A description of the hydraulic output unit is given.

  20. Overview of heat transfer and fluid flow problem areas encountered in stirling engine modeling

    SciTech Connect

    Tew, R.C. Jr.

    1988-02-01

    NASA Lewis Research Center has been managing Stirling engine development programs for over a decade. In addition to contractual programs, this work has included in-house engine testing and development of engine computer models. Attempts to validate Stirling engine computer models with test data have demonstrated that engine thermodynamic losses need better characterization. Various Stirling engine thermodynamic losses and efforts that are underway to characterize these losses are discussed.

  1. Computer model of catalytic combustion/Stirling engine heater head

    NASA Technical Reports Server (NTRS)

    Chu, E. K.; Chang, R. L.; Tong, H.

    1981-01-01

    The basic Acurex HET code was modified to analyze specific problems for Stirling engine heater head applications. Specifically, the code can model: an adiabatic catalytic monolith reactor, an externally cooled catalytic cylindrical reactor/flat plate reactor, a coannular tube radiatively cooled reactor, and a monolithic reactor radiating to upstream and downstream heat exchangers.

  2. SPIKE-2: a Practical Stirling Engine for Kilowatt Level Solar Power

    NASA Technical Reports Server (NTRS)

    Beale, W. T.

    1984-01-01

    Recent advances in the art of free piston Stirling engine design make possible the production of 1-10kW free piston Stirling linear alternator engine, hermetically sealed, efficient, durable and simple in construction and operation. Power output is in the form of single or three phase 60 Hz. AC, or DC. The three phase capability is available from single machines without need of external conditioning. Engine voltage control regains set voltage within 5 cycles in response to any load change. The existing SPIKE-2 design has an engine alternator efficiency of 25% at 650 C heater wall temperature and a service life of over three years in solar service. The same system can be scaled over a range of at least 100 watts to 25kW.

  3. Test results of applicative 100 W Stirling engine

    SciTech Connect

    Hirata, Koichi; Kagawa, Noboru; Takeuchi, Makoto; Yamashita, Iwao; Isshiki, Naotsugu; Hamaguchi, Kazuhiro

    1996-12-31

    A small 100 W displacer-type Stirling engine, Ecoboy-SCM81, has been developed by a committee of the Japan Society of Mechanical Engineers (JSME). The engine contains unique features, including an expansion cylinder which is heated by either combustion gas or direct solar energy. Also, a simple cooling system rejects heat from the working fluid. A displacer piston has both heating and cooling inner tubes for the working fluid which flows to and from outer tubes. The outer tubes for heating were located at the top of the expansion cylinder and the outer tubes for cooling were located in the middle of the cylinder. A regenerator is located in the displacer piston. The components of the engine adopted some new technologies. For instance, a porous type matrix consisting of pressed zigzag stainless steel wires were adopted for the regenerator. The matrix is practical for Stirling engines because it can be made at low cost and the assembling process is simplified.

  4. A self-circulating heat exchanger for use in stirling and thermoacoustic-stirling engines

    SciTech Connect

    Backhaus, S. N.; Reid, R. S.

    2004-01-01

    A major technical hurdle to the implementation of large Stirling engines or thermoacoustic engines is the reliability, performance, and manufacturability of the hot heat exchanger that brings high-temperature heat into the engine. Unlike power conversion devices that utilize steady flow, the oscillatory nature of the flow in Stirling and thermoacoustic engines restricts the length of a traditional hot heat exchanger to a peak-to-peak gas displacement, which is usually around 0.2 meters or less. To overcome this restriction, a new hot heat exchanger has been devised that uses a fluid diode in a looped pipe, which is resonantly driven by the oscillating gas pressure in the engine itself, to circulate the engine's working fluid around the loop. Instead of thousands of short, intricately interwoven passages that must be individually sealed, this new design consists of a few pipes that are typically 10 meters long. This revolutionary approach eliminates thousands of hermetic joints, pumps the engine's working fluid to and from a remote heat source without using moving parts, and does so without compromising on heat transfer surface area. Test data on a prototype loop integrated with a 1-kW thermoacoustic engine will be presented.

  5. 40 kW Stirling engine for solid fuel

    SciTech Connect

    Carlsen, H.; Ammundsen, N.; Traerup, J.

    1996-12-31

    The external combustion in a Stirling engine makes it very attractive for utilization of solid fuels in decentralized combined heat and power (CHP) plants. Only few projects have concentrated on the development of Stirling engines specifically for biomass. In this project a Stirling engine has been designed primarily for utilization of wood chips. Maximum shaft power is 40 kW corresponding to an electric output of 36 kW. Biomass needs more space in the combustion chamber compared to gas and liquid fuels, and a large heat transfer area is necessary. The design of the new Stirling engine has been adapted to the special demands of combustion of wood chips, resulting in a large engine compared to engines for gas or liquid fuels. The engine has four-cylinders arranged in a square. The design is made as a hermetic unit, where the alternator is built into the pressurized crankcase so that dynamic seals are avoided. Grease lubricated bearings are used in a special designed crank mechanism, which eliminates guiding forces on the pistons Helium is used as working gas at 4 MPa mean pressure. The first test of the 40 kW engine with natural gas as fuel has been made in the laboratory, and the results are in agreement with predicted results from simulation programs. The wood chips combustion system has been tested for some time with very promising results. When the laboratory test of the engine is finished, the test of the complete system will be initiated. The paper describes the engine and results from the test program. Expectations to maintenance and operation problems are also discussed.

  6. Solar-powered Stirling engines - Energy converters on earth and in space

    NASA Astrophysics Data System (ADS)

    Kleinwaechter, H.; Kleinwaechter, J.

    The development of the crankshaft Stirling engine has resulted in a machine suitable for energy conversion on earth and in space, using solar energy. The principle of the Stirling engine is discussed, the realization of the engine in a variety of applications is shown. The advantages of the free-piston design of the Stirling engine are addressed, and the engine's use in a receiver antenna for direct reception from satellites is considered.

  7. Optimal power and efficiency of quantum Stirling heat engines

    NASA Astrophysics Data System (ADS)

    Yin, Yong; Chen, Lingen; Wu, Feng

    2017-01-01

    A quantum Stirling heat engine model is established in this paper in which imperfect regeneration and heat leakage are considered. A single particle which contained in a one-dimensional infinite potential well is studied, and the system consists of countless replicas. Each particle is confined in its own potential well, whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions. Based on the Schrödinger equation, the expressions of power output and efficiency for the engine are obtained. Effects of imperfect regeneration and heat leakage on the optimal performance are discussed. The optimal performance region and the optimal values of important parameters of the engine cycle are obtained. The results obtained can provide some guidelines for the design of a quantum Stirling heat engine.

  8. A survey of oscillating flow in Stirling engine heat exchangers

    NASA Technical Reports Server (NTRS)

    Simon, Terrence W.; Seume, Jorge R.

    1988-01-01

    Similarity parameters for characterizing the effect of flow oscillation on wall shear stress, viscous dissipation, pressure drop and heat transfer rates are proposed. They are based on physical agruments and are derived by normalizing the governing equations. The literature on oscillating duct flows, regenerator and porous media flows is surveyed. The operating characteristics of the heat exchanger of eleven Stirling engines are discribed in terms of the similarity parameters. Previous experimental and analytical results are discussed in terms of these parameters and used to estimate the nature of the oscillating flow under engine operating conditions. The operating points for many of the modern Stirling engines are in or near the laminar to turbulent transition region. In several engines, working fluid does not pass entirely through heat exchangers during a cycle. Questions that need to be addressed by further research are identified.

  9. 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.

  10. Design of a new type of rotary Stirling engine

    SciTech Connect

    Abenavoli, R.I.; Dong, W.; Fedele, L.; Sciaboni, A.

    1996-12-31

    The Stirling machine has had wide diffusion only in cold or cryogenic applications (Philips) while the engine, despite big efforts of large Companies (Philips, Westinghouse, General Motors, etc.), never definitively reached the market; today new interest is raised correlated with environmental and energy related considerations. Thus, researchers efforts are addressed towards the design of innovative and more competitive Stirling engine configurations, like the one here proposed. This paper describes the configuration of a new, rotary Stirling engine. In the cold part of the engine, the working fluid is compressed by a rotating element, then it passes through the regenerator from the cold to the hot end, where it absorbs the heat and expands in the high pressure and temperature area. The high pressure working fluid pushes on the rotating element (the so called rotator) and the engine outputs power. In the design, compression and expansion volumes change with the rotation. Two rotators are connected with a set of gears: therefore, the engine transmission system is simplified and dimensions are reduced.

  11. How to Overcome Numerical Challenges to Modeling Stirling Engines

    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 a range of missions, including 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 in 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-FI technique is presented in detail.

  12. Overview of free-piston Stirling engine technology for space power application

    SciTech Connect

    Slaby, J.G.

    1987-01-01

    An overview is presented of the National Aeronautics and Space Administration (NASA) Lewis Research Center (LeRC) free-piston Stirling engine activities directed toward space-power application. One of the major elements of the program is the development of advanced power conversion of which the Stirling cycle is a viable candidate. Under this program the status of the 25 kWe opposed-piston Space Power Demonstrator Engine (SPDE) is presented. Technology work is also conducted on heat-exchanger concepts, both design and fabrication, to minimize the number of joints as well as to enhance the heat transfer in the heater. Design parameters and conceptual design features are also presented for a 25 kWe, single-cylinder free-piston Stirling space-power converter. Projections are made for future space-power requirements over the next few decades along with a recommendation to consider the use of dynamic power-conversion systems - either solar or nuclear. A description of a study to investigate the feasibility of scaling a single-cylinder free-piston Stirling space-power module to the 150 kWe power range is presented.

  13. Overview of free-piston Stirling engine technology for space power application

    NASA Technical Reports Server (NTRS)

    Slaby, Jack G.

    1987-01-01

    An overview is presented of free-piston Stirling engine activities, directed toward space power applications. One of the major elements of the program is the development of advanced power conversion. Under this program the status of the 25 kWe opposed-piston Space Power Demonstrator Engine (SPDE) is presented. Initial differences between predicted and experimental power outputs and power output influenced by variations in regenerators are discussed. Technology work was conducted on heat-exchanger concepts to minimize the number of joints as well as to enhance the heat transfer in the heater. Design parameters and conceptual design features are also presented for a 25 kWe, single-cylinder free-piston Stirling space power converter. Projections are made for future space power requirements over the next few decades along with a recommendation to consider the use of dynamic power conversion systems, either solar or nuclear. A cursory comparison is presented showing the mass benefits of a Stirling system over a Brayton system for the same peak temperature and output power. A description of a study to investigate the feasibility of scaling a single-cylinder free-piston Stirling space power module to the 150 kWe power range is presented.

  14. Testing of a variable-stroke Stirling engine

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Allen, David J.

    1986-01-01

    Testing of a variable-stroke Stirling engine at NASA Lewis has been completed. In support of the DOE Stirling Engine Highway Vehicle Systems Program, the engine was tested for about 70 hours total with both He and H2 as working fluids over a range of pressures and strokes. A direct comparison was made of part-load efficiencies obtained with variable-stroke (VS) and variable-pressure operation. Two failures with the variable-angle swash-plate drive system limited testing to low power levels. These failures are not thought to be caused by problems inherent with the VS concept but do emphasize the need for careful design in the area of the crossheads.

  15. A Miniature TES powered Stirling-cycle engine

    SciTech Connect

    Schneider, J.A.; Holl, S.L.; Schalansky, C.P.

    1984-08-01

    Miniature Stirling-cycle engines are under development for use in powering implantable ventricular assist devices. Approaches which have been employed to drive these devices rely on the generation of either hydraulic or pneumatic power. This generated power is converted by hydraulic or pneumatic logic control to mechanical power which, in turn, actuates pusher-plate blood pumps. The logic control enables the blood pump to be cycled synchronously (counter-pulsatile mode) with the heart. Because Stirling-cycle engines are heated externally, a variety of energy sources can be used. Restrictions for this application are for the energy source to be small and self contained while suppling heat in the range of 500 to 850/sup 0/C. Historically these systems were designed to be powered by a radioisotope. More recently, thermal energy system utilizing the latent heat of fusion of fluoride eutectic salts are being developed to power the engine for 8 hours of tether free operation.

  16. Testing of a variable-stroke Stirling engine

    NASA Technical Reports Server (NTRS)

    Thieme, L. G.; Allen, D. J.

    1986-01-01

    Testing of a variable-stroke Stirling engine at NASA Lewis has been completed. In support of the DOE Stirling Engine Highway Vehicle Systems Program, the engine was tested for about 70 hours total with both He and H2 working fluids over a range of pressures and strokes. A direct comparison was made of part-load efficiencies obtained with variable-stroke (VS) and variable-pressure operation. Two failures with the variable-angle swash-plate drive system limited testing to low power levels. These failures are not thought to be caused by problems inherent with the VS concept but do emphasize the need for careful design in the area of the crossheads.

  17. Potential impacts of Brayton- and Stirling-cycle engines

    SciTech Connect

    Heft, R.C.

    1980-11-15

    Two engine technologies (Brayton cycle and Stirling cycle) currently being pursued by the US Department of Energy were examined for their potential impacts if they achieved commercial viability. An economic analysis of the expected response of buyers to the attributes of the alternative engines was performed. Hedonic coefficients for vehicle fuel efficiency, performance and size were estimated for domestic cars based upon historical data. The marketplace value of the fuel efficiency enhancement provided by Brayton or Stirling engines was estimated. The effect upon various economic sectors of a large scale change-over from conventional to alternate engines was estimated using an economic input-output analysis. Primary effects were found in fuels refining, non-ferroalloy ores and ferroalloy smelting. Secondary effects were found in mining, transport, and capital financing. Under the assumption of 10 years for plant conversions and 1990 and 1995 as the introduction date for turine and Stirling engines respectively, the comparative fuel savings and present value of the future savings in fuel costs were estimated.

  18. Validation of Organics for Advanced Stirling Convertor (ASC)

    NASA Astrophysics Data System (ADS)

    Shin, E. Eugene; Scheiman, Dan; Cybulski, Michelle; Quade, Derek; Inghram, Linda; Burke, Chris

    2008-01-01

    Organic materials are an essential part of the Advanced Stirling Convertor (ASC) construction as adhesives, potting, wire insulation, lubrication coatings, bobbins, bumpers, insulators, thread lockers. Since a long lifetime of such convertors to be used in the Advanced Stirling Radioisotope Generator (ASRG), sometimes up to 17 years, is required in various space applications such as Mars rovers, deep space missions, and lunar surface power, performance, durability and reliability of those organics should be critically evaluated in every possible material-process-fabrication-service environment relations. The objective of this study was to evaluate, validate, and recommend organics for use in ASCs. Systematic and extensive evaluation methodologies were developed and conducted for various organic materials. The overall efforts dealing with organics materials for the last several years are summarized in the key areas, e.g., process-fabrication optimization, adhesive bonding integrity, outgassing, thermal stability, and durability

  19. Conceptual design of an advanced Stirling conversion system for terrestrial power generation

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A free piston Stirling engine coupled to an electric generator or alternator with a nominal kWe power output absorbing thermal energy from a nominal 100 square meter parabolic solar collector and supplying electric power to a utility grid was identified. The results of the conceptual design study of an Advanced Stirling Conversion System (ASCS) were documented. The objectives are as follows: define the ASCS configuration; provide a manufacturability and cost evaluation; predict ASCS performance over the range of solar input required to produce power; estimate system and major component weights; define engine and electrical power condidtioning control requirements; and define key technology needs not ready by the late 1980s in meeting efficiency, life, cost, and with goalds for the ASCS.

  20. Evaluation of a Stirling engine heater bypass with the NASA Lewis nodal-analysis performance code

    SciTech Connect

    Sullivan, T.J.

    1986-05-01

    In support of the US Department of Energy's Stirling Engine Highway Vehicle Systems program, the NASA Lewis Research Center investigated whether bypassing the P-40 Stirling engine heater during regenerative cooling would improve the engine thermal efficiency. The investigation was accomplished by using the Lewis nodal-analysis Stirling engine computer model. Bypassing the P-40 Stirling engine heater at full power resulted in a rise in the indicated thermal efficiency from 40.6 to 41.0 percent. For the idealized (some losses not included) heater bypass that was analyzed, this benefit is not considered significant.

  1. DOE/NASA automotive Stirling engine project - Overview 86

    NASA Technical Reports Server (NTRS)

    Beremand, D. G.; Shaltens, R. K.

    1986-01-01

    The DOE/NASA Automotive Stirling Engine Project is reviewed and its technical progress and status are presented. Key technologies in materials, seals, and piston rings are progressing well. Seven first-generation engines, and modifications thereto, have accumulated over 15,000 hr of test time, including 1100 hr of in-vehicle testing. Results indicate good progress toward the program goals. The first second-generation engine is now undergoing initial testing. It is expected that the program goal of a 30-percent improvement in fuel economy will be achieved in tests of a second-generation engine in a Celebrity vehicle.

  2. NASA/DOE automotive Stirling engine project. Overview 1986

    SciTech Connect

    Beremand, D.G.; Shaltens, R.K.

    1986-01-01

    The DOE/NASA Automotive Stirling Engine Project is reviewed and its technical progress and status are presented. Key technologies in materials, seals, and piston rings are progressing well. Seven first-generation engines, and midifications thereto, have accumulated over 15 000 hr of test time, including 1100 hr of in-vehicle testing. Results indicate good progress toward the program goals. The first second-generation engine is now undergoing initial testing. It is expected that the program goal of a 30-percent improvement in fuel economy will be achieved in tests of a second-generation engine in a Celebrity vehicle.

  3. NASA/DOE automotive Stirling engine project: Overview 1986

    NASA Technical Reports Server (NTRS)

    Beremand, D. G.; Shaltens, R. K.

    1986-01-01

    The DOE/NASA Automotive Stirling Engine Project is reviewed and its technical progress and status are presented. Key technologies in materials, seals, and piston rings are progressing well. Seven first-generation engines, and modifications thereto, have accumulated over 15,000 hr of test time, including 1100hr of in-vehicle testing. Results indicate good progress toward the program goals. The first second-generation engine is now undergoing initial testing. It is expected that the program goal of a 30-percent improvement in fuel economy will be achieved in tests of a second-generation engine in a Celebrity vehicle.

  4. A novel Stirling engine with an elliptic drive

    SciTech Connect

    Fang, H.W.; Herold, K.E.; Holland, H.M.; Beach, E.H.

    1996-12-31

    The concept of the Stirling cycle seems quite simple when presented as a cycle involving two constant temperature and two constant volume processes. The reality of machines that have evolved from the Stirling concept is considerably more complicated. Most real machines employ a drive mechanism that approximates a sinusoidal volume variation for each of the cylinders. This results in an overall volume variation that only poorly approximates the constant volume processes postulated in the classic definition of a Stirling cycle. The difficulties of achieving the piston motions necessary to attain the discontinuous motions of the classic cycle are well known and, as a result, the sinusoidal motions are widely accepted as an inevitable compromise. It is noted that free piston Stirling machines are not constrained in the same manner. However, the discussion here focuses on kinematic drive machines. In the current study, a Rider-type engine with an elliptic drive is modeled with the objective of clarifying the potential of a more ideal volume variation. This drive mechanism is the subject of a US Patent filed with Serial Number 08/360,052 on 20 December 1994.

  5. Performance analysis for second-design space Stirling engine model

    NASA Astrophysics Data System (ADS)

    Ogiwara, Sachio; Fujiwara, Tsutomu; Eguchi, Kunihisa; Nakamura, Yoshihiro

    A hybrid free-piston Stirling research engine, called NALSEM 125, has been tested since 1988 as part of a solar dynamic power technology program. It is a gamma-type Stirling driven linear-alternator machine with helium as a working fluid. The objective of the experimental program is to understand the thermodynamic and dynamic mechanisms of the free piston engine integrated with a magnet-moving alternator. After the first phase engine experiments of NALSEM 125, a second design Stirling engine of NALSEM 125 R has been tested. By using a second-order analytical tool, some design modifications were performed to provide much more stable dynamic operations over a required operating range, as well as to incorporate an electric heater head simulating a hot interface of 12 sodium heat pipes. Describes in this paper are thermodynamic performance data of NALSEM 125R operations, which are also compared with the computational analysis, considering the power losses resulting from pressure drop and gas leakage.

  6. Oscillating flow loss test results in Stirling engine heat exchangers

    NASA Technical Reports Server (NTRS)

    Koester, G.; Howell, S.; Wood, G.; Miller, E.; Gedeon, D.

    1990-01-01

    The results are presented for a test program designed to generate a database of oscillating flow loss information that is applicable to Stirling engine heat exchangers. The tests were performed on heater/cooler tubes of various lengths and entrance/exit configurations, on stacked and sintered screen regenerators of various wire diameters and on Brunswick and Metex random fiber regenerators. The test results were performed over a range of oscillating flow parameters consistent with Stirling engine heat exchanger experience. The tests were performed on the Sunpower oscillating flow loss rig which is based on a variable stroke and variable frequency linear drive motor. In general, the results are presented by comparing the measured oscillating flow losses to the calculated flow losses. The calculated losses are based on the cycle integration of steady flow friction factors and entrance/exit loss coefficients.

  7. Stirling engine - Approach for long-term durability assessment

    NASA Astrophysics Data System (ADS)

    Tong, Michael T.; Bartolotta, Paul A.; Halford, Gary R.; Freed, Alan D.

    The approach employed by NASA Lewis for the long-term durability assessment of the Stirling engine hot-section components is summarized. The approach consists of: preliminary structural assessment; development of a viscoplastic constitutive model to accurately determine material behavior under high-temperature thermomechanical loads; an experimental program to characterize material constants for the viscoplastic constitutive model; finite-element thermal analysis and structural analysis using a viscoplastic constitutive model to obtain stress/strain/temperature at the critical location of the hot-section components for life assessment; and development of a life prediction model applicable for long-term durability assessment at high temperatures. The approach should aid in the provision of long-term structural durability and reliability of Stirling engines.

  8. Testing of the United Stirling 4-95 solar Stirling engine on test bed concentrator

    NASA Technical Reports Server (NTRS)

    Nelving, H. G.

    1984-01-01

    The objectives with the testing, test set-ups, component designs, and the results of the testing of the solar Stirling engine in a parabolic dish system are presented. The most important tests are characterization of receivers, full day performance of complete system, cavity and aperture window test including influence from windeffects, control system tests, radiator system tests and special temperature measurements with infrared camera. The influence on performance of flux distribution depnding on concentrator alignment, and the optimum receiver operating criteria when balancing flux and temperatures on cooled receiver surface while avoiding flux on uncooled surfaces are also discussed.

  9. Advanced Stirling receiver development program, phase 1

    NASA Astrophysics Data System (ADS)

    Lurio, Charles A.

    1990-07-01

    Critical technology experiments were designed and developed to evaluate the Stirling cavity heat pipe receiver for a space solar power system. Theoretical criteria were applied to the design of a module for containing energy storage phase change material while avoiding thermal ratcheting. Zero-g drop tower tests, without phase change, were conducted to affirm that the bubble location required to avoid ratcheting could be achieved without the use of container materials that are wetted by the phase change material. A full scale module was fabricated, but not tested. A fabrication method was successfully developed for the sodium evaporator dome, with a sintered screen wick, to be used as the focal point for the receiver. Crushing of the screen during hydroforming was substantially reduced over the results of other researchers by using wax impregnation. Superheating of the sodium in the wick under average flux conditions is expected to be under 10K. A 2000K furnace which will simulate solar flux conditions for testing the evaporator dome was successfully built and tested.

  10. Advanced Stirling receiver development program, phase 1

    NASA Technical Reports Server (NTRS)

    Lurio, Charles A.

    1990-01-01

    Critical technology experiments were designed and developed to evaluate the Stirling cavity heat pipe receiver for a space solar power system. Theoretical criteria were applied to the design of a module for containing energy storage phase change material while avoiding thermal ratcheting. Zero-g drop tower tests, without phase change, were conducted to affirm that the bubble location required to avoid ratcheting could be achieved without the use of container materials that are wetted by the phase change material. A full scale module was fabricated, but not tested. A fabrication method was successfully developed for the sodium evaporator dome, with a sintered screen wick, to be used as the focal point for the receiver. Crushing of the screen during hydroforming was substantially reduced over the results of other researchers by using wax impregnation. Superheating of the sodium in the wick under average flux conditions is expected to be under 10K. A 2000K furnace which will simulate solar flux conditions for testing the evaporator dome was successfully built and tested.

  11. Simulational nanoengineering: Molecular dynamics implementation of an atomistic Stirling engine.

    PubMed

    Rapaport, D C

    2009-04-01

    A nanoscale-sized Stirling engine with an atomistic working fluid has been modeled using molecular dynamics simulation. The design includes heat exchangers based on thermostats, pistons attached to a flywheel under load, and a regenerator. Key aspects of the behavior, including the time-dependent flows, are described. The model is shown to be capable of stable operation while producing net work at a moderate level of efficiency.

  12. DOE/NASA Automotive Stirling Engine Project overview '83

    NASA Technical Reports Server (NTRS)

    Beremand, D. G.

    1982-01-01

    An overview of the DOE/NASA Automotive Stirling Engine Project is presented. The background and objectives of the project are reviewed. Project activities are described and technical progress and status are presented and assessed. Prospects for achieving the objective 30% fuel economy improvement are considered good. The key remaining technology issues are primarily related to life, reliability and cost, such as piston rod seals, and low cost heat exchanges.

  13. Failure analysis of a Stirling engine heat pipe

    NASA Technical Reports Server (NTRS)

    Moore, Thomas J.; Cairelli, James E.; Khalili, Kaveh

    1989-01-01

    Failure analysis was conducted on a heat pipe from a Stirling Engine test rig which was designed to operate at 1073 K. Premature failure had occurred due to localized overheating at the leading edge of the evaporator fin. It was found that a crack had allowed air to enter the fin and react with the sodium coolant. The origin of the crack was found to be located at the inner surface of the Inconel 600 fin where severe intergranular corrosion had taken place.

  14. Advanced Stirling Convertor Testing at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Blaze, Gina M.

    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.

  15. 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.

  16. Advanced Stirling Duplex Materials Assessment for Potential Venus Mission Heater Head Application

    NASA Technical Reports Server (NTRS)

    Ritzert, Frank; Nathal, Michael V.; Salem, Jonathan; Jacobson, Nathan; Nesbitt, James

    2011-01-01

    This report will address materials selection for components in a proposed Venus lander system. The lander would use active refrigeration to allow Space Science instrumentation to survive the extreme environment that exists on the surface of Venus. The refrigeration system would be powered by a Stirling engine-based system and is termed the Advanced Stirling Duplex (ASD) concept. Stirling engine power conversion in its simplest definition converts heat from radioactive decay into electricity. Detailed design decisions will require iterations between component geometries, materials selection, system output, and tolerable risk. This study reviews potential component requirements against known materials performance. A lower risk, evolutionary advance in heater head materials could be offered by nickel-base superalloy single crystals, with expected capability of approximately 1100C. However, the high temperature requirements of the Venus mission may force the selection of ceramics or refractory metals, which are more developmental in nature and may not have a well-developed database or a mature supporting technology base such as fabrication and joining methods.

  17. 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.

  18. Experimental investigation of a thermoacoustic-Stirling refrigerator driven by a thermoacoustic-Stirling heat engine.

    PubMed

    Luo, E C; Dai, W; Zhang, Y; Ling, H

    2006-12-22

    In this paper, a thermally-driven thermoacoustic refrigerator system without any moving part is reported. This refrigeration system consists of a thermoacoustic-Stirling heat engine and a thermoacoustic-Stirling refrigerator; that is, the former is the driving source for the latter. Both the subsystems are designed to operate on traveling-wave mode. In the experiment, it was found that the DC-flows had significant negative effect on the heat engine and the refrigerator. To suppress these DC-flows, two flexible membranes were inserted into the two subsystems and worked very well. Then extensive experiments were made to test the influence of different parameters on refrigeration performance of the whole system. The system has so far achieved a no-load temperature of -65 degrees C, a cooling capacity of about 270 W at -20 degrees C and 405 W at 0 degrees C; in fact, the result showed a good prospect of the refrigeration system in room-temperature cooling such as food refrigeration and air-conditioning.

  19. Thermal energy storage for the Stirling engine powered automobile

    NASA Technical Reports Server (NTRS)

    Morgan, D. T. (Editor)

    1979-01-01

    A thermal energy storage (TES) system developed for use with the Stirling engine as an automotive power system has gravimetric and volumetric storage densities which are competitive with electric battery storage systems, meets all operational requirements for a practical vehicle, and can be packaged in compact sized automobiles with minimum impact on passenger and freight volume. The TES/Stirling system is the only storage approach for direct use of combustion heat from fuel sources not suitable for direct transport and use on the vehicle. The particular concept described is also useful for a dual mode TES/liquid fuel system in which the TES (recharged from an external energy source) is used for short duration trips (approximately 10 miles or less) and liquid fuel carried on board the vehicle used for long duration trips. The dual mode approach offers the potential of 50 percent savings in the consumption of premium liquid fuels for automotive propulsion in the United States.

  20. Design of a pool boiler heat transport system for a 25 kWe advanced Stirling conversion system

    NASA Technical Reports Server (NTRS)

    Anderson, W. G.; Rosenfeld, J. H.; Noble, J.; Kesseli, J.

    1991-01-01

    The overall operating temperature and efficiency of solar-powered Stirling engines can be improved by adding a heat transport system to more uniformly supply heat to the heater head tubes. One heat transport system with favorable characteristics is an alkali metal pool boiler. An alkali metal pool boiler heat transport system was designed for a 25-kW advanced Stirling conversion system (ASCS). Solar energy concentrated on the absorber dome boils a eutectic mixture of sodium and potassium. The alkali metal vapors condense on the heater head tubes, supplying the Stirling engine with a uniform heat flux at a constant temperature. Boiling stability is achieved with the use of an enhanced boiling surface and noncondensible gas.

  1. Automotive Stirling engine development program - Overview and status report

    NASA Technical Reports Server (NTRS)

    Nightingale, N. P.

    1983-01-01

    The current status of the automotive-Stirling-engine development program being undertaken by DOE and NASA Lewis is reviewed. The program goals and the reference-engine design are explained, and the modifications introduced to improve performance and lower manufacturing costs are discussed and illustrated, including part-power optimization; increased operating temperature (from 720 to 820 C); 45.4-kg weight reduction; elimination of Co and reduction of Cr used; and improved seals, ceramic components, and high-temperature alloys. The test program, some difficulties encountered, and results after 2042 h are summarized.

  2. Overview of NASA Lewis Research Center free-piston Stirling engine technology activities applicable to space power systems

    SciTech Connect

    Slaby, J.G.

    1987-01-01

    An overview is presented of the National Aeronautics and Space Administration (NASA) Lewis Research Center free-piston Stirling engine activities directed toward space-power application. One of the major elements of the program is the development of advanced power conversion concepts of which the Stirling cycle is a viable candidate. Under this program the research findings of the 25 kWe opposed-piston Space Power Demonstrator Engine (SPDE) are presented. Included in the SPDE discussion are initial differences between predicted and experimental power outputs and power output influenced by variations in regenerators. Projections are made for future space-power requirements over the next few decades. A cursory comparison is presented showing the mass benefits that a Stirling system has over a Brayton system for the same peak temperature and output power.

  3. Preliminary design of an advanced Stirling system for terrestrial solar energy conversion

    NASA Technical Reports Server (NTRS)

    White, M. A.; Noble, J. E.; Emigh, S. G.; Ross, B. A.; Lehmann, G. A.

    1990-01-01

    A preliminary design was generated for an advanced Stirling conversion system (ASCS) that will be capable of delivering about 25 kW of electric power to an electric utility grid. Stirling engines are being evaluated for terrestrial solar applications. A two-year task to complete detailed design, fabrication, assembly and testing of an ASCS prototype began in April, 1990. The ASCS is designed to deliver maximum power per year over a range of solar inputs with a design life of 30 years (60,000 h). The ACSC has a long-term cost goal of about $450 per kilowatt, exclusive of the 11-m parabolic dish concentrator. The proposed system includes a Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator. The major thrusts of the preliminary design are described, including material selection for the hot-end components, heat transport system (reflux pool boiler) design, system thermal response, improved manufacturability, FMECA/FTA analysis, updated manufacturing cost estimate, and predicted system performance.

  4. Alkali metal compatibility testing of candidate heater head materials for a Stirling engine heat transport system

    NASA Technical Reports Server (NTRS)

    Noble, Jack E.; Hickman, Gary L.; Grobstein, Toni

    1991-01-01

    The authors describe work performed as part of the 25-kWe advanced Stirling conversion system project. Liquid alkali metal compatibility is being assessed in an ongoing test program to evaluate candidate heater head materials and fabrication processes at the temperatures and operating conditions required for Stirling engines. Specific materials under evaluation are alloy 713LC, alloy 713LC coated with nickel aluminide, and Udimet 720, each in combination with Waspaloy. The tests were run at a constant 700 C. A eutectic alloy of sodium and potassium (NaK) was the working fluid. Titanium sheet in the system was shown to be an effective oxygen getter. Metallographic and microchemical examination of material surfaces, joints, and their interfaces revealed little or no corrosion after 1000 h. Tests are in progress, with up to 10,000 h exposure.

  5. 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.

  6. 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.

  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 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.

  9. Thermal lag test engines evaluated and compared to equivalent Stirling engines

    SciTech Connect

    Tailer, P.L.

    1995-12-31

    Thermal lag engines run both free piston and with pistons kinematically linked. Free piston, a thermal lag engine may be the simplest of all piston engines as it is valveless and has only one moving part, the piston. Horizontal and vertical thermal lag engines with substantially identical cooled pistons and cylinders are tested and evaluated, particularly as to power density. The horizontal engine has an elongated, small diameter heated chamber and the vertical engine has a large diameter flat heated chamber. Both heated chambers may be altered in volume to maximize engine power at optimum compression ratios. The power density of unpressurized thermal lag engines is compared to that of early commercial Stirling cycle unpressurized air engines. The comparison indicates the potential for applying well-known modern Stirling technology to thermal lag engines.

  10. Fast Whole-Engine Stirling Analysis

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

    This presentation discusses the simulation approach to whole-engine for physical consistency, REV regenerator modeling, grid layering for smoothness, and quality, conjugate heat transfer method adjustment, high-speed low cost parallel cluster, and debugging.

  11. Control of Stirling engine. Simplified, compressible model

    NASA Astrophysics Data System (ADS)

    Plotnikov, P. I.; Sokołowski, J.; Żochowski, A.

    2016-06-01

    A one-dimensional free boundary problem on a motion of a heavy piston in a tube filled with viscous gas is considered. The system of governing equations and boundary conditions is derived. The obtained system of differential equations can be regarded as a mathematical model of an exterior combustion engine. The existence of a weak solution to this model is proved. The problem of maximization of the total work of the engine is considered.

  12. Automotive Stirling Engine Mod 1 Design Review, volume 2

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The auxiliaries and the control system for the ASE MOD I: (1) provide the required fuel and air flows for a well controlled combustion process, generating heat to the Stirling cycle; (2) provide a driver acceptable method for controlling the power output of the engine; (3) provide adequate lubrication and cooling water circulation; (4) generate the electric energy required for engine and vehicle operation; (5) provide a driver acceptable method for starting, stopping and monitoring the engine; and (6) provide a guard system, that protects the engine at component or system malfunction. The control principles and the way the different components and sub-systems interact are described as well as the different auxiliaries, the air fuel system, the power control systems and the electronics. The arrangement and location of auxiliaries and other major components are also examined.

  13. Integral finned heater and cooler for stirling engines

    SciTech Connect

    Corey, John A.

    1984-01-01

    A piston and cylinder for a Stirling engine and the like having top and bottom meshing or nesting finned conical surfaces to provide large surface areas in close proximity to the working gas for good thermal (addition and subtraction of heat) exchange to the working gas and elimination of the usual heater and cooler dead volume. The piston fins at the hot end of the cylinder are perforated to permit the gas to pass into the piston interior and through a regenerator contained therein.

  14. Loss terms in free-piston Stirling-engine models. Final Technical Report

    SciTech Connect

    Gordon, L.B.

    1992-01-01

    Various models for free piston Stirling engines are reviewed. Initial models were developed primarily for design purposes and to predict operating parameters, especially efficiency. More recently, however, such models have been used to predict engine stability. Free piston Stirling engines have no kinematic constraints and stability may not only be sensitive to the load, but also to various nonlinear loss and spring constraints. The present understanding is reviewed of various loss mechanisms for free piston Stirling engines and how they have been incorporated into engine models is discussed.

  15. Design study of a kinematic Stirling engine for dispered solar electric power systems

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The concept evaluation shows that the four cylinder double acting U type Stirling engine with annular regenerators is the most suitable engine type for the 15 kW solar application with respect to design, performance and cost. Results show that near term performance for a metallic Stirling engine is 42% efficiency. Further improved components show an impact on efficiency of the future metallic engine to 45%. Increase of heater temperature, through the introduction of ceramic components, contribute the greatest amount to achieve high efficiency goals. Future ceramic Stirling engines for solar applications show an efficiency of around 50%.

  16. 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.

  17. 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.

  18. Overview of the 1985 NASA Lewis Research Center SP-100 free-piston Stirling engine activities

    NASA Technical Reports Server (NTRS)

    Slaby, J.

    1985-01-01

    This effort is keyed on the design, fabrication, assembly, and testing of a 25 kWe Stirling space-power technology-feasibility demonstrator engine. Another facet of the SP-100 project covers the status of a 9000-hr endurance test conducted on a 2 kWe free-piston Stirling/linear alternator system employing hydrostatic gas bearings. Dynamic balancing of the RE-1000 engine (a 1 kWe free-piston Stirling engine) using a passive dynamic absorber will be discussed along with the results of a parametric study showing the relationships of Stirling power converter specific weight and efficiency as functions of Stirling engine heater to cooler temperature ratio. Planned tests will be described covering a hydrodynamic gas bearing concept for potential SP-100 application.

  19. Theoretical and experimental study on regenerative rotary displacer Stirling engine

    SciTech Connect

    Raggi, L.; Katsuta, Masafumi; Isshiki, Naotsugu; Isshiki, Seita

    1997-12-31

    Recently a quite new type of hot air engine called rotary displacer engine, in which the displacer is a rotating disk enclosed in a cylinder, has been conceived and developed. The working gas, contained in a notch excavated in the disk, is heated and cooled alternately, on account of the heat transferred through the enclosing cylinder that is heated at one side and cooled at the opposite one. The gas temperature oscillations cause the pressure fluctuations that get out mechanical power acting on a power piston. In order to attempt to increase the performances for this kind of engine, the authors propose three different regeneration methods. The first one comprises two coaxial disks that, revolving in opposite ways, cause a temperature gradient on the cylinder wall and a regenerative axial heat conduction through fins shaped on the cylinder inner wall. The other two methods are based on the heat transferred by a proper closed circuit that in one case has a circulating liquid inside and in the other one is formed by several heat pipes working each one for different temperatures. An engine based on the first principle, the Regenerative Tandem Contra-Rotary Displacer Stirling Engine, has been realized and experimented. In this paper experimental results with and without regeneration are reported comparatively with a detailed description of the unity. A basic explanation of the working principle of this engine and a theoretical analysis investigating the main influential parameters for the regenerative effect are done. This new rotating displacer Stirling engines, for their simplicity, are expected to attain high rotational speed especially for applications as demonstration and hobby unities.

  20. Test results and facility description for a 40-kilowatt stirling engine

    NASA Technical Reports Server (NTRS)

    Kelm, G. G.; Cairelli, J. E.; Walter, R. J.

    1981-01-01

    A 40 kilowatt Stirling engine, its test support facilities, and the experimental procedures used for these tests are described. Operating experience with the engine is discussed, and some initial test results are presented

  1. CO2 laser-driven Stirling engine. [space power applications

    NASA Technical Reports Server (NTRS)

    Lee, G.; Perry, R. L.; Carney, B.

    1978-01-01

    A 100-W Beale free-piston Stirling engine was powered remotely by a CO2 laser for long periods of time. The engine ran on both continuous-wave and pulse laser input. The working fluid was helium doped with small quantities of sulfur hexafluoride, SF6. The CO2 radiation was absorbed by the vibrational modes of the sulfur hexafluoride, which in turn transferred the energy to the helium to drive the engine. Electrical energy was obtained from a linear alternator attached to the piston of the engine. Engine pressures, volumes, and temperatures were measured to determine engine performance. It was found that the pulse radiation mode was more efficient than the continuous-wave mode. An analysis of the engine heat consumption indicated that heat losses around the cylinder and the window used to transmit the beam into the engine accounted for nearly half the energy input. The overall efficiency, that is, electrical output to laser input, was approximately 0.75%. However, this experiment was not designed for high efficiency but only to demonstrate the concept of a laser-driven engine. Based on this experiment, the engine could be modified to achieve efficiencies of perhaps 25-30%.

  2. 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.

  3. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terry; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Wood, Gary; Qiu, Songgang

    2007-01-01

    A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM (electric discharge machining). During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90% random fiber currently used in small 100 W Stirling space-power convertors in the Reynolds Number range of interest (50-100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6-9%; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to

  4. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Qiu, Songgang

    2007-01-01

    A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM. During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90 percent random fiber currently used in small approx.100 W Stirling space-power convertors-in the Reynolds Number range of interest (50 to 100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6 to 9 percent; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to 1200 C

  5. Stirling Space Engine Program. Volume 1; Final Report

    NASA Technical Reports Server (NTRS)

    Dhar, Manmohan

    1999-01-01

    The objective of this program was to develop the technology necessary for operating Stirling power converters in a space environment and to demonstrate this technology in full-scale engine tests. Hardware development focused on the Component Test Power Converter (CTPC), a single cylinder, 12.5-kWe engine. Design parameters for the CTPC were 150 bar operating pressure, 70 Hz frequency, and hot-and cold-end temperatures of 1050 K and 525 K, respectively. The CTPC was also designed for integration with an annular sodium heat pipe at the hot end, which incorporated a unique "Starfish" heater head that eliminated highly stressed brazed or weld joints exposed to liquid metal and used a shaped-tubed electrochemical milling process to achieve precise positional tolerances. Selection of materials that could withstand high operating temperatures with long life were another focus. Significant progress was made in the heater head (Udimet 700 and Inconel 718 and a sodium-filled heat pipe); the alternator (polyimide-coated wire with polyimide adhesive between turns and a polyimide-impregnated fiberglass overwrap and samarium cobalt magnets); and the hydrostatic gas bearings (carbon graphite and aluminum oxide for wear couple surfaces). Tests on the CTPC were performed in three phases: cold end testing (525 K), engine testing with slot radiant heaters, and integrated heat pipe engine system testing. Each test phase was successful, with the integrated engine system demonstrating a power level of 12.5 kWe and an overall efficiency of 22 percent in its maiden test. A 1500-hour endurance test was then successfully completed. These results indicate the significant achievements made by this program that demonstrate the viability of Stirling engine technology for space applications.

  6. 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.

  7. SPRE I Free-Piston Stirling Engine Testing at NASA Lewis Research Center

    SciTech Connect

    Cairelli, J.E.

    1994-09-01

    As part of the NASA funded portion of the SP-100 Advanced Technology Program the Space Power Research Engine (SPRE I) was designed and built to serve as a research tool for evaluation and development of advanced Stirling engine concepts. The SPRE I is designed to produce 12.5 kW electrical power when operated with helium at 15 MPa and with an absolute temperature ratio of two. The engine is now under test in a new test facility which was designed and built at NASA LeRC specifically to test the SPRE I. This paper describes the SPRE I, the NASA test facility, the initial SPRE I test results, and future SPRE I test plans.

  8. Low pressure high speed Stirling air engine. Final technical report

    SciTech Connect

    Ross, M.A.

    1980-06-16

    The purpose of this project was to design, construct and test a simple, appropriate technology low pressure, high speed, wood-fired Stirling air engine of 100 W output. The final design was a concentric piston/displacer engine of 454 in. bore and 1 in. stroke with a rhombic drive mechanism. The project engine was ultimately completed and tested, using a propane burner for all tests as a matter of convenience. The 100 W aim was exceeded, at atmospheric pressure, over a wide range of engine speed with the maximum power being 112 W at 1150 rpm. A pressure can was constructed to permit pressurization; however the grant funds were running out, and the only pressurized power test attempted was unsuccessful due to seal difficulties. This was a disappointment because numerous tests on the 4 cubic inch engine suggested power would be more than doubled with pressurization at 25 psig. A manifold was designed and constructed to permit operation of the engine over a standard No. 40 pot bellied stove. The engine was run successfully, but at reduced speed and power, over this stove. The project engine started out being rather noisy in operation, but modifications ultimately resulted in a very quiet engine. Various other difficulties and their solutions also are discussed. (LCL)

  9. The low temperature differential Stirling engine with working fluid operated on critical condition

    SciTech Connect

    Naso, V.; Dong, W.; Lucentini, M.; Capata, R.

    1998-07-01

    The research and development of low temperature differential Stirling engine has a great potential market since a lot of thermal energy at low temperature can supply it and the cost of this kind of engine is lower than general Stirling engine. The characteristics of low compression ratio and low differential temperature Stirling engine may be satisfied with working fluid compressed on critical conditions. By combining two phase heat transfer with forced convective flow in compression space and through the regenerator in the engine, a new heat transfer coefficient emerges capable of absorbing and releasing high heat fluxes without the corresponding low temperature increase. The current analysis focuses on the study of Stirling engines with working fluid compressed on critical conditions, thus at two-phase heat transfer in compression space and regenerator of the engine under forced convective flow conditions.

  10. 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.

  11. Cost and price estimate of Brayton and Stirling engines in selected production volumes

    NASA Technical Reports Server (NTRS)

    Fortgang, H. R.; Mayers, H. F.

    1980-01-01

    The methods used to determine the production costs and required selling price of Brayton and Stirling engines modified for use in solar power conversion units are presented. Each engine part, component and assembly was examined and evaluated to determine the costs of its material and the method of manufacture based on specific annual production volumes. Cost estimates are presented for both the Stirling and Brayton engines in annual production volumes of 1,000, 25,000, 100,000 and 400,000. At annual production volumes above 50,000 units, the costs of both engines are similar, although the Stirling engine costs are somewhat lower. It is concluded that modifications to both the Brayton and Stirling engine designs could reduce the estimated costs.

  12. Microfabricated Segmented-Involute-Foil Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Qiu, Songgang; Wood, Gary; Kelly, Kevin; McLean, Jeffrey

    2010-01-01

    An involute-foil regenerator was designed, microfabricated, and tested in an oscillating-flow test rig. The concept consists of stacked involute-foil nickel disks (see figure) microfabricated via a lithographic process. Test results yielded a performance of about twice that of the 90-percent random-fiber currently used in small Stirling converters. The segmented nature of the involute- foil in both the axial and radial directions increases the strength of the structure relative to wrapped foils. In addition, relative to random-fiber regenerators, the involute-foil has a reduced pressure drop, and is expected to be less susceptible to the release of metal fragments into the working space, thus increasing reliability. The prototype nickel involute-foil regenerator was adequate for testing in an engine with a 650 C hot-end temperature. This is lower than that required by larger engines, and high-temperature alloys are not suited for the lithographic microfabrication approach.

  13. Free-piston stirling engine endurance test program

    NASA Technical Reports Server (NTRS)

    Dochat, G.; Rauch, J.; Antonelli, G.

    1983-01-01

    The Free-Piston Stirling Engine (FPSE) has the potential to be a long-lived, highly reliable, power conversion device attractive for many product applications such as space, residential, or remote-site power. The purpose of endurance testing the FPSE is to demonstrate its potential for long life. The endurance program was directed at obtaining 1000 operational hours under various test conditions: low power, full stroke, duty cycle, and stop/start. Critical performance parameters were measured to note any change and/or trend. Inspections were conducted to measure and compare critical seal/bearing clearance. The engine performed well throughout the program, completing the 1000 hours. Hardware inspection, including the critical clearances, showed no significant change in hardware or clearance dimensions. The performance parameters did not exhibit any increasing or decreasing trends. The test program confirms the potential for long-life FPSE applications. Additional testing is planned to increase the test hours to 10,000.

  14. Validation of thermodynamic and mechanical models of free piston Stirling engines

    NASA Astrophysics Data System (ADS)

    Carlini, M.; Cichy, M.; Mancini, M.

    1985-12-01

    Two distinctive physical-mathematical models for a free piston Stirling engine have been carried out, the thermodynamic and the dynamic ones, which are linked together by the outputs of the first becoming the inputs of the second. The paper then deals with the results reached by the authors on a test bench constructed ad hoc for a Beale free-piston Stirling engine of low power. The before mentioned models have been also validated by means of a comparison with the results of tests effected on the Stirling Beale engine.

  15. 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.

  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. Insoluble coatings for Stirling engine heat pipe condenser surfaces. Final report

    SciTech Connect

    Dussinger, P.M.

    1993-09-01

    The work done by Thermacore, Inc., Lancaster, Pennsylvania, for the Phase 1, 1992 SBIR National Aeronautics and Space Administration Contract, Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces' is described. The work was performed between January 1992 and July 1992. Stirling heat engines are being developed for electrical power generation use on manned and unmanned earth orbital and planetary missions. Dish Stirling solar systems and nuclear reactor Stirling systems are two of the most promising applications of the Stirling engine electrical power generation technology. The sources of thermal energy used to drive the Stirling engine typically are non-uniform in temperature and heat flux. Liquid metal heat pipe receivers are used as thermal transformers and isothermalizers to deliver the thermal energy at a uniform high temperature to the heat input section of the Stirling engine. The use of a heat pipe receiver greatly enhances system efficiency and potential life span. One issue that is raised during the design phase of heat pipe receivers is the potential solubility corrosion of the Stirling engine heat input section by the liquid metal working fluid. This Phase 1 effort initiated a program to evaluate and demonstrate coatings, applied to nickel based Stirling engine heater head materials, that are practically 'insoluble' in sodium, potassium, and NaK. This program initiated a study of nickel aluminide as a coating and developed and demonstrated a heat pipe test vehicle that can be used to test candidate materials and coatings. Nickel 200 and nickel aluminide coated Nickel 200 were tested for 1000 hours at 800 C at a condensation heat flux of 25 W/sq cm. Subsequent analyses of the samples showed no visible sign of solubility corrosion of either coated or uncoated samples. The analysis technique, photomicrographs at 200X, has a resolution of better than 2.5 microns (.0001 in).

  19. Quantum Stirling heat engine and refrigerator with single and coupled spin systems

    NASA Astrophysics Data System (ADS)

    Huang, Xiao-Li; Niu, Xin-Ya; Xiu, Xiao-Ming; Yi, Xue-Xi

    2014-02-01

    We study the reversible quantum Stirling cycle with a single spin or two coupled spins as the working substance. With the single spin as the working substance, we find that under certain conditions the reversed cycle of a heat engine is NOT a refrigerator, this feature holds true for a Stirling heat engine with an ion trapped in a shallow potential as its working substance. The efficiency of quantum Stirling heat engine can be higher than the efficiency of the Carnot engine, but the performance coefficient of the quantum Stirling refrigerator is always lower than its classical counterpart. With two coupled spins as the working substance, we find that a heat engine can turn to a refrigerator due to the increasing of the coupling constant, this can be explained by the properties of the isothermal line in the magnetic field-entropy plane.

  20. Comparison of steady-state and transient CVS cycle emission of an automotive Stirling engine

    NASA Technical Reports Server (NTRS)

    Farrell, R. A.; Bolton, R. J.

    1983-01-01

    The Automotive Stirling Engine Development Program is to demonstrate a number of goals for a Stirling-powered vehicle. These goals are related to an achievement of specified maximum emission rates, a combined cycle fuel economy 30 percent better than a comparable internal-combustion engine-powered automobile, multifuel capability, competitive cost and reliability, and a meeting of Federal standards concerning noise and safety. The present investigation is concerned with efforts related to meeting the stringent emission goals. Attention is given to the initial development of a procedure for predicting transient CVS urban cycle gaseous emissions from steady-state engine data, taking into account the employment of the test data from the first-generation automotive Stirling engine. A large amount of steady-state data from three Mod I automotive Stirling engines were used to predict urban CVS cycle emissions for the Mod I Lerma vehicle.

  1. Characteristics, finite element analysis, test description, and preliminary test results of the STM4-120 kinematic Stirling engine

    SciTech Connect

    Linker, K.L.; Rawlinson, K.S.; Smith, G.

    1991-10-01

    The Department of Energy`s Solar Thermal Program has as one of its program elements the development and evaluation of conversion device technologies applicable to dish-electric systems. The primary research and development combines a conversion device (heat engine), solar receiver, and generator mounted at the focus of a parabolic dish concentrator. The Stirling-cycle heat engine was identified as the conversion device for dish-electric with the most potential for meeting the program`s goals for efficiency, reliability, and installed cost. To advance the technology toward commercialization, Sandia National Laboratories has acquired a Stirling Thermal Motors, Inc., kinematic Stirling engine, STM4-120, for evaluation. The engine is being bench-tested at Sandia`s Engine Test Facility and will be combined later with a solar receiver for on-sun evaluation. This report presents the engine characteristics, finite element analyses of critical engine components, test system layout, instrumentation, and preliminary performance results from the bench test.

  2. Process and apparatus for reducing the loss of hydrogen from Stirling engines

    SciTech Connect

    Alger, D.L.

    1987-03-24

    A Stirling engine assembly is described which defines a working gas volume therein, the Stirling engine assembly comprising: a working gas reservoir for storing a working gas at a pressure greater than pressure of the working gas in the working volume of the Stirling engine; a trap cell operatively connected between an outlet of the reservoir and the Stirling engine working volume. The trap cell includes an enclosure having porous windows at either end thereof and a sorbent with an affinity for water vapor therein, such that water vapor adsorbed on the sorbent diffuses into the hydrogen passing from the reservoir into the working engine; a compressor means for drawing working gas from the Stirling engine working volume, through the trap cell and pumping the working gas into the hydrogen reservoir. The sorbent in the trap cell at the reduced pressure caused by the compressor adsorbs water vapor from the working gas such that substantially dry working gas is pumped by the compressor into the reservoir. The working gas is doped with water vapor by the tank cell as it passes into the Stirling engine and is dried by the trap cell as it is removed from the working engine for storage in the reservoir to prevent condensation of water vapor in the reservoir.

  3. Variable cycle stirling engine and gas leakage control system therefor

    SciTech Connect

    Otters, J.

    1984-12-25

    An improved thermal engine of the type having a displacer body movable between the hot end and the cold end of a chamber for subjecting a fluid within that chamber to a thermodynamic cycle and having a work piston driven by the fluid for deriving a useful work output. The work piston pumps a hydraulic fluid and a hydraulic control valve is connected in line with the hydraulic output conduit such that the flow of hydraulic fluid may be restricted to any desired degree or stopped altogether. The work piston can therefore be controlled by means of a controller device independently from the movement of the displacer such that a variety of engine cycles can be obtained for optimum engine efficiency under varying load conditions. While a Stirling engine cycle is particularly contemplated, other engine cycles may be obtained by controlling the movement of the displacer and work pistons. Also disclosed are a working gas recovery system for controlling leakage of working gas from the displacer chamber, and a compound work piston arrangement for preventing leakage of hydraulic fluid around the work piston into the displacer chamber.

  4. The lambda-scheme method applied to Stirling engines

    NASA Astrophysics Data System (ADS)

    Franco, R.

    1985-12-01

    An integration method of the motion equations is the so-called 'lambda-scheme': such a method suggests that, in the numerical procedure of the approximation of the derivatives in space with finite differences, the physical domains of dependence have to be correctly taken into account, according to the wave propagation through the flow. In the lambda-scheme method, the codes are simple, the computing time is kept very low, while accuracy (second-order in space and time) of the results is very satisfactory. As a matter of fact, the simulation model here discussed leads to a deeper analysis and a closer prediction of Stirling engine performances. As a first approach, a feasibility analysis is carried out for an expansion space-heat exchanger flow duty simulation.

  5. Stirling engine power control and motion conversion mechanism

    DOEpatents

    Marks, David T.

    1983-01-01

    A motion conversion device for converting between the reciprocating motion of the pistons in a Stirling engine and the rotating motion of its output shaft, and for changing the stroke and phase of the pistons, includes a lever pivoted at one end and having a cam follower at the other end. The piston rod engages the lever intermediate its ends and the cam follower engages a cam keyed to the output shaft. The lever pivot can be moved to change the length of the moment arm defined between the cam follower and the piston rod the change the piston stroke and force exerted on the cam, and the levers can be moved in opposite directions to change the phase between pistons.

  6. Enhanced air/fuel mixing for automotive stirling engine turbulator-type combustors

    SciTech Connect

    Riecke, George T.; Stotts, Robert E.

    1992-01-01

    The invention relates to the improved combustion of fuel in a combustion chamber of a stirling engine and the like by dividing combustion into primary and secondary combustion zones through the use of a diverter plate.

  7. Considerations on the external combustion system of the Stirling hot gas engine

    NASA Technical Reports Server (NTRS)

    Zacharias, F.

    1983-01-01

    After an introduction on the Stirling engine the external combustion system as well as the general loss division and efficiencies are described. The requirements for the combustion system and different variants of the combustion system are compared and discussed.

  8. Proof of concept of a magnetically coupled Stirling engine-driven heat pump

    SciTech Connect

    Shonder, J.A. ); Chen, Gong; McEntee, J. )

    1992-01-01

    A prototype magnetically-coupled Stirling engine-driven heat pump module has been designed and fabricated by Sunpower, Inc. under sponsorship of the US Department of Energy and the Oak Ridge National Laboratory (ORNL). Preliminary testing indicates that the magnetic coupling is an effective means for transmitting power from a free-piston Stirling engine to a refrigerant compressor. Compared with other power transmission concepts, the magnetic coupling has relatively low cost, and will help make commercial development of Stirling-driven heat pumps more likely in the future.

  9. Proof of concept of a magnetically coupled Stirling engine-driven heat pump

    SciTech Connect

    Shonder, J.A.; Chen, Gong; McEntee, J.

    1992-08-01

    A prototype magnetically-coupled Stirling engine-driven heat pump module has been designed and fabricated by Sunpower, Inc. under sponsorship of the US Department of Energy and the Oak Ridge National Laboratory (ORNL). Preliminary testing indicates that the magnetic coupling is an effective means for transmitting power from a free-piston Stirling engine to a refrigerant compressor. Compared with other power transmission concepts, the magnetic coupling has relatively low cost, and will help make commercial development of Stirling-driven heat pumps more likely in the future.

  10. Low-temperature Stirling Engine for Geothermal Electricity Generation

    SciTech Connect

    Stillman, Greg; Weaver, Samuel P.

    2013-03-27

    Up to 2700 terawatt-hours per year of geothermal electricity generation capacity has been shown to be available within North America, typically with wells drilled into geologically active regions of the earth's crust where this energy is concentrated (Huttrer, 2001). Of this potential, about half is considered to have temperatures high enough for conventional (steam-based) power production, while the other half requires unconventional power conversion approaches, such as organic Rankine cycle systems or Stirling engines. If captured and converted effectively, geothermal power generation could replace up to 100GW of fossil fuel electric power generation, leading to a significant reduction of US power sector emissions. In addition, with the rapid growth of hydro-fracking in oil and gas production, there are smaller-scale distributed power generation opportunities in heated liquids that are co-produced with the main products. Since 2006, Cool Energy, Inc. (CEI) has designed, fabricated and tested four generations of low-temperature (100°C to 300°C) Stirling engine power conversion equipment. The electric power output of these engines has been demonstrated at over 2kWe and over 16% thermal conversion efficiency for an input temperature of 215°C and a rejection temperature of 15°C. Initial pilot units have been shipped to development partners for further testing and validation, and significantly larger engines (20+ kWe) have been shown to be feasible and conceptually designed. Originally intended for waste heat recovery (WHR) applications, these engines are easily adaptable to geothermal heat sources, as the heat supply temperatures are similar. Both the current and the 20+ kWe designs use novel approaches of self-lubricating, low-wear-rate bearing surfaces, non-metallic regenerators, and high-effectiveness heat exchangers. By extending CEI's current 3 kWe SolarHeart® Engine into the tens of kWe range, many additional applications are possible, as one 20 k

  11. Low-Power Baseline Test Results for the GPU 3 Stirling Engine

    NASA Technical Reports Server (NTRS)

    Thieme, L. G.

    1979-01-01

    A 7.5 kW (10 hp) Stirling engine was converted to a research configuration in order to obtain data for validating Stirling-cycle computer simulations. Test results for a range of heater-tube gas temperatures, mean compression-space pressures, and engine speeds with both helium and hydrogen as the working fluid are summarized. An instrumentation system to determine indicated work is described and preliminary results are presented.

  12. 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.

  13. Space Power Free-Piston Stirling Engine Scaling Study

    NASA Technical Reports Server (NTRS)

    Jones, D.

    1989-01-01

    The design feasibility study is documented of a single cylinder, free piston Stirling engine/linear alternator (FPSE/LA) power module generating 150 kW-electric (kW sub e), and the determination of the module's maximum feasible power level. The power module configuration was specified to be a single cylinder (single piston, single displacer) FPSE/LA, with tuning capacitors if required. The design requirements were as follows: (1) Maximum electrical power output; (2) Power module thermal efficiency equal to or greater than 20 percent at a specific mass of 5 to 8 kg/kW(sub e); (3) Heater wall temperature/cooler wall temperature = 1050 K/525 K; (4) Sodium heat-pipe heat transport system, pumped loop NaK (sodium-potassium eutectic mixture) rejection system; (5) Maximum power module vibration amplitude = 0.0038 cm; and (6) Design life = 7 years (60,000 hr). The results show that a single cylinder FPSE/LA is capable of meeting program goals and has attractive scaling attributes over the power range from 25 to 150 kW(sub e). Scaling beyond the 150 kW(sub e) power level, the power module efficiency falls and the power module specific mass reaches 10 kg/kW(sub e) at a power output of 500 kW(sub e). A discussion of scaling rules for the engine, alternator, and heat transport systems is presented, along with a detailed description of the conceptual design of a 150 kW(sub e) power module that meets the requirements. Included is a discussion of the design of a dynamic balance system. A parametric study of power module performance conducted over the power output range of 25 to 150 kW(sub e) for temperature ratios of 1.7, 2.0, 2.5, and 3.0 is presented and discussed. The results show that as the temperature ratio decreases, the efficiency falls and specific mass increases. At a temperature ratio of 1.7, the 150 kW(sub e) power module cannot satisfy both efficiency and specific mass goals. As the power level increases from 25 to 150 kW(sub e) at a fixed temperature ratio, power

  14. Assessment of a 40-kilowatt stirling engine for underground mining applications

    NASA Technical Reports Server (NTRS)

    Cairelli, J. E.; Kelm, G. G.; Slaby, J. G.

    1982-01-01

    An assessment of alternative power souces for underground mining applications was performed. A 40-kW Stirling research engine was tested to evaluate its performance and emission characteristics when operated with helium working gas and diesel fuel. The engine, the test facility, and the test procedures are described. Performance and emission data for the engine operating with helium working gas and diesel fuel are reported and compared with data obtained with hydrogen working gas and unleaded gasoline fuel. Helium diesel test results are compared with the characteristics of current diesel engines and other Stirling engines. External surface temperature data are also presented. Emission and temperature results are compared with the Federal requirements for diesel underground mine engines. The durability potential of Stirling engines is discussed on the basis of the experience gaind during the engine tests.

  15. Preliminary results for a two-dimensional simulation of the working process of a Stirling engine

    SciTech Connect

    Makhkamov, K.K.; Ingham, D.B.

    1998-07-01

    Stirling engines have several potential advantages over existing types of engines, in particular they can use renewable energy sources for power production and their performance meets the demands on the environmental security. In order to design Stirling Engines properly, and to put into effect their potential performance, it is important to more accurately mathematically simulate its working process. At present, a series of very important mathematical models are used for describing the working process of Stirling Engines and these are, in general, classified as models of three levels. All the models consider one-dimensional schemes for the engine and assume a uniform fluid velocity, temperature and pressure profiles at each plane of the internal gas circuit of the engine. The use of two-dimensional CFD models can significantly extend the capabilities for the detailed analysis of the complex heat transfer and gas dynamic processes which occur in the internal gas circuit, as well as in the external circuit of the engine. In this paper a two-dimensional simplified frame (no construction walls) calculation scheme for the Stirling Engine has been assumed and the standard {kappa}-{var{underscore}epsilon} turbulence model has been used for the analysis of the engine working process. The results obtained show that the use of two-dimensional CFD models gives the possibility of gaining a much greater insight into the fluid flow and heat transfer processes which occur in Stirling Engines.

  16. 5-kWe Free-piston Stirling Engine Convertor

    NASA Technical Reports Server (NTRS)

    Chapman, Peter A.; Vitale, Nicholas A.; Walter, Thomas J.

    2008-01-01

    The high reliability, long life, and efficient operation of Free-Piston Stirling Engines (FPSEs) make them an attractive power system to meet future space power requirements with less mass, better efficiency, and less total heat exchanger area than other power convertor options. FPSEs are also flexible in configuration as they can be coupled with many potential heat sources and various heat input systems, heat rejection systems, and power management and distribution systems. Development of a 5-kWe Stirling Convertor Assembly (SCA) is underway to demonstrate the viability of an FPSE for space power. The design is a scaled-down version of the successful 12.5-kWe Component Test Power Converter (CTPC) developed under NAS3-25463. The ultimate efficiency target is 25% overall convertor efficiency (electrical power out over heat in). For the single cylinder prototype now in development, cost and time constraints required use of economical and readily available materials (steel versus beryllium) and components (a commercially available linear alternator) and thus lower efficiency. The working gas is helium at 150 bar mean pressure. The design consists of a displacer suspended on internally pumped gas bearings and a power piston/alternator supported on flexures. Non-contacting clearance seals are used between internal volumes. Heat to and from the prototype convertor is done via pumped liquid loops passing through shell and tube heat exchangers. The preliminary and detail designs of the convertor, controller, and support systems (heating loop, cooling loop, and helium supply system) are complete and all hardware is on order. Assembly and test of the prototype at Foster- Miller is planned for early 2008, when work will focus on characterizing convertor dynamics and steady-state operation to determine maximum power output and system efficiency. The device will then be delivered to Auburn University where assessments will include start-up and shutdown characterization and

  17. Assessment and economic analysis of the MOD III Stirling-engine driven chiller system. Final report, October 1989-July 1990

    SciTech Connect

    Moryl, J.

    1990-07-01

    The Stirling engine is an inherently clean and efficient engine. With the requirements for environmentally benign emissions and high energy efficiency, the Stirling engine is an attractive alternative to both internal combustion (IC) engines and electric motors. The study evaluated a Stirling-engine-driven chiller package. Technically, the Stirling engine is a good selection as a compressor drive, with inherently low vibrations, quiet operation, long life, and low maintenance. Exhaust emissions are below the projected 1995 stringent California standards. Economically, the Stirling-engine-driven chiller is a viable alternative to both IV-engine and electric-driven chillers, trading off slightly higher installed cost against lower total operating expenses. The penetration of a small portion of the projected near-term stationary engine market opportunity will provide the volume production basis to achieve competitively priced engines.

  18. Understanding of the Dynamics of the Stirling Convertor Advanced by Structural Testing

    NASA Technical Reports Server (NTRS)

    Hughes, William O.

    2003-01-01

    The NASA Glenn Research Center, the U.S. Department of Energy, and the Stirling Technology Company (STC) are developing a highly efficient, long-life, free-piston Stirling convertor for use as an advanced spacecraft power system for future NASA missions, including deep-space and Mars surface applications. As part of this development, four structural dynamic test programs were recently performed on Stirling Technology Demonstration Convertors (TDC's) that were designed and built by STC under contract to the Department of Energy. This testing was performed in Glenn's Structural Dynamics Laboratory and Microgravity Emissions Laboratory. The first test program, in November and December 1999, demonstrated that the Stirling TDC could withstand the harsh random vibration experienced during a typical spacecraft launch and survive with no structural damage or functional power performance degradation. This was a critical step in enabling the use of Stirling convertors for future spacecraft power systems. The most severe test was a 12.3grms random vibration test, with test durations of 3 min per axis. The random vibration test levels were chosen to simulate, with margin, the maximum anticipated launch vibration conditions. The Microgravity Emissions Laboratory is typically used to measure the dynamics produced by operating space experiments and the resulting impact to the International Space Station's microgravity environment. For the second Stirling dynamic test program, performed in January 2001, the Microgravity Emissions Laboratory was used to characterize the structure-borne disturbances produced by the normal operation of a pair of Stirling convertors. The forces and moments produced by the normal operation of a Stirling system must be recognized and controlled, if necessary, so that other nearby spacecraft components, such as cameras, are not adversely affected. The Stirling convertor pair emitted relatively benign tonal forces at its operational frequency and

  19. Preliminary designs for 25 kWe advanced Stirling conversion systems for dish electric applications

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1990-01-01

    Under the Department of Energy's (DOE) Solar Thermal Technology Program, Sandia National Laboratories is evaluating heat engines for terrestrial Solar Distributed Heat Receivers. The Stirling engine has been identified by Sandia as one of the most promising 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 Stirling engine technology development activities directed toward a dynamic power source for space applications. Space power systems requirements include high reliability, very long life, low vibration and high 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. Preliminary designs feature a free-piston Stirling engine, a liquid metal heat transport system, and a means to provide nominally 25 kW electric power to a utility grid while meeting DOE's performance and long term cost goals. The Cummins design incorporates a linear alternator to provide the electrical output, while the STC design generates electrical power indirectly through a hydraulic pump/motor coupled to an induction generator. Both designs for the ASCS's will use technology which can reasonably be expected to be available in the early 1990's.

  20. Preliminary designs for 25 kWe advanced Stirling conversion systems for dish electric applications

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1990-01-01

    Under the Department of Energy's (DOE) Solar Thermal Technology Program, Sandia National Laboratories is evaluating heat engines for terrestrial Solar Distributed Heat Receivers. The Stirling engine has been identified by Sandia as one of the most promising 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 Stirling engine technology development activities directed toward a dynamic power source for space applications. Space power systems requirements include high reliability, very long life, low vibration and high 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. Preliminary designs feature a free-piston Stirling engine, a liquid metal heat transport system, and a means to provide nominally 25 kW electric power to a utility grid while meeting DOE's performance and long term cost goals. The Cummins design incorporates a linear alternator to provide the electrical output, while the STC design generates electrical power indirectly through a hydraulic pump/motor coupled to an induction generator. Both designs for the ASCS's will use technology which can reasonably be expected to be available in the early 1990's

  1. Preliminary designs for 25 kWe advanced Stirling conversion systems for dish electric applications

    NASA Astrophysics Data System (ADS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    Under the Department of Energy's (DOE) Solar Thermal Technology Program, Sandia National Laboratories is evaluating heat engines for terrestrial Solar Distributed Heat Receivers. The Stirling engine has been identified by Sandia as one of the most promising 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 Stirling engine technology development activities directed toward a dynamic power source for space applications. Space power systems requirements include high reliability, very long life, low vibration and high 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. Preliminary designs feature a free-piston Stirling engine, a liquid metal heat transport system, and a means to provide nominally 25 kW electric power to a utility grid while meeting DOE's performance and long term cost goals. The Cummins design incorporates a linear alternator to provide the electrical output, while the STC design generates electrical power indirectly through a hydraulic pump/motor coupled to an induction generator. Both designs for the ASCS's will use technology which can reasonably be expected to be available in the early 1990's.

  2. A comparison of Stirling engines for use with a 25 kW dish-electric conversion system

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.

    1987-01-01

    Two designs for an advanced Stirling conversion system (ASCS) are described. The objective of the ASCS is to generate about 25 kW of electric power to an electric utility grid at an engine/alternator target cost of $300.00/kW at the manufacturing rate of 10,000 unit/yr. Both designs contain a free-piston Stirling engine (FPSE), a heat transport system, solar receiver, a means to generate electric power, the necessary auxiliaries, and a control system. The major differences between the two concepts are: one uses a 25 kWe single-piston FPSE which incorporates a linear alternator to directly convert the energy to electricity on the utility grid; and in the second design, electrical power is generated indirectly using a hydraulic output to a ground based hydraulic motor coupled to a rotating alternator. Diagrams of the two designs are presented.

  3. Effect of water on hydrogen permeability. [Stirling engines

    NASA Technical Reports Server (NTRS)

    Hulligan, D. D.; Tomazic, W. A.

    1984-01-01

    Doping of hydrogen with CO or CO2 was developed to reduce hydrogen permeation in Stirling engines by forming low permeability oxide coatings in the heater tubes. An end product of this process is water - which can condense in the cold parts of the engine system. If the water vapor is reduced to a low enough level, the hydrogen can reduce the oxide coating resulting in increased permeability. The equilibrium level of water (oxygen bearing gas) required to avoid reduction of the oxide coating was investigated. Results at 720 C and 13.8 MPa have shown that: (1) pure hydrogen will reduce the coating; (2) 500 ppm CO (500 ppm water equivalent) does not prevent the reduction; and (3) 500 ppm CO2 (1000 ppm water) appears to be close to the equilibrium level. Further tests are planned to define the equilibrium level more precisely and to extend the data to 820 C and 3.4, 6.9, and 13.8 MPa.

  4. Stirling engines. January 1984-May 1988 (Citations from the NTIS data base). Report for January 1984-May 1988

    SciTech Connect

    Not Available

    1988-05-01

    This bibliography contains citations concerning Stirling-engine technology. Design, performance testing, development, engine problems, temperature control, computerized simulation, and reliability are considered. Applications of various types of Stirling engines to automobiles, the utilization of solar energy, and an artificial heart system are included. (This updated bibliography contains 237 citations, 63 of which are new entries to the previous edition.)

  5. Stirling engines. January 1984-June 1989 (Citations from the NTIS data base). Report for January 1984-June 1989

    SciTech Connect

    Not Available

    1989-06-01

    This bibliography contains citations concerning Stirling engine technology. Design, performance testing, development, engine problems, temperature control, computerized simulation, and reliability are considered. Applications of various types of Stirling engines to automobiles, the utilization of solar energy, and an artificial heart system are included. (This updated bibliography contains 273 citations, 36 of which are new entries to the previous edition.)

  6. Reliability Quantification of Advanced Stirling Convertor (ASC) Components

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin R.; Korovaichuk, Igor; Zampino, Edward

    2010-01-01

    The Advanced Stirling Convertor, is intended to provide power for an unmanned planetary spacecraft and has an operational life requirement of 17 years. Over this 17 year mission, the ASC must provide power with desired performance and efficiency and require no corrective maintenance. Reliability demonstration testing for the ASC was found to be very limited due to schedule and resource constraints. Reliability demonstration must involve the application of analysis, system and component level testing, and simulation models, taken collectively. Therefore, computer simulation with limited test data verification is a viable approach to assess the reliability of ASC components. This approach is based on physics-of-failure mechanisms and involves the relationship among the design variables based on physics, mechanics, material behavior models, interaction of different components and their respective disciplines such as structures, materials, fluid, thermal, mechanical, electrical, etc. In addition, these models are based on the available test data, which can be updated, and analysis refined as more data and information becomes available. The failure mechanisms and causes of failure are included in the analysis, especially in light of the new information, in order to develop guidelines to improve design reliability and better operating controls to reduce the probability of failure. Quantified reliability assessment based on fundamental physical behavior of components and their relationship with other components has demonstrated itself to be a superior technique to conventional reliability approaches based on utilizing failure rates derived from similar equipment or simply expert judgment.

  7. 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.

  8. Test results of a Stirling engine utilizing heat exchanger modules with an integral heat pipe

    SciTech Connect

    Skupinski, R.C.; Tower, L.K.; Madi, F.J.; Brusk, K.D.

    1993-04-01

    The Heat Pipe Stirling Engine (HP-1000), a free-piston Stirling engine incorporating three heat exchanger modules, each having a sodium filled heat pipe, has been tested at the NASA-Lewis Research Center as part of the Civil Space Technology Initiative (CSTI). The heat exchanger modules were designed to reduce the number of potential flow leak paths in the heat exchanger assembly and incorporate a heat pipe as the link between the heat source and the engine. An existing RE-1000 free-piston Stirling engine was modified to operate using the heat exchanger modules. This paper describes heat exchanger module and engine performance during baseline testing. Condenser temperature profiles, brake power, and efficiency are presented and discussed.

  9. Test results of a Stirling engine utilizing heat exchanger modules with an integral heat pipe

    NASA Technical Reports Server (NTRS)

    Skupinski, Robert C.; Tower, Leonard K.; Madi, Frank J.; Brusk, Kevin D.

    1993-01-01

    The Heat Pipe Stirling Engine (HP-1000), a free-piston Stirling engine incorporating three heat exchanger modules, each having a sodium filled heat pipe, has been tested at the NASA-Lewis Research Center as part of the Civil Space Technology Initiative (CSTI). The heat exchanger modules were designed to reduce the number of potential flow leak paths in the heat exchanger assembly and incorporate a heat pipe as the link between the heat source and the engine. An existing RE-1000 free-piston Stirling engine was modified to operate using the heat exchanger modules. This paper describes heat exchanger module and engine performance during baseline testing. Condenser temperature profiles, brake power, and efficiency are presented and discussed.

  10. Development and Validation of Linear Alternator Models for the Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Metscher, Jonathan F.; Lewandowski, Edward J.

    2015-01-01

    Two models of the linear alternator of the Advanced Stirling Convertor (ASC) have been developed using the Sage 1-D modeling software package. The first model relates the piston motion to electric current by means of a motor constant. The second uses electromagnetic model components to model the magnetic circuit of the alternator. The models are tuned and validated using test data and also compared against each other. Results show both models can be tuned to achieve results within 7 of ASC test data under normal operating conditions. Using Sage enables the creation of a complete ASC model to be developed and simulations completed quickly compared to more complex multi-dimensional models. These models allow for better insight into overall Stirling convertor performance, aid with Stirling power system modeling, and in the future support NASA mission planning for Stirling-based power systems.

  11. Development and Validation of Linear Alternator Models for the Advanced Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Metscher, Jonathan F.; Lewandowski, Edward

    2014-01-01

    Two models of the linear alternator of the Advanced Stirling Convertor (ASC) have been developed using the Sage 1-D modeling software package. The first model relates the piston motion to electric current by means of a motor constant. The second uses electromagnetic model components to model the magnetic circuit of the alternator. The models are tuned and validated using test data and compared against each other. Results show both models can be tuned to achieve results within 7% of ASC test data under normal operating conditions. Using Sage enables the creation of a complete ASC model to be developed and simulations completed quickly compared to more complex multi-dimensional models. These models allow for better insight into overall Stirling convertor performance, aid with Stirling power system modeling, and in the future support NASA mission planning for Stirling-based power systems.

  12. Thermoacoustic refrigerators and engines comprising cascading stirling thermodynamic units

    DOEpatents

    Backhaus, Scott; Swift, Greg

    2013-06-25

    The present invention includes a thermoacoustic assembly and method for improved efficiency. The assembly has a first stage Stirling thermal unit comprising a main ambient heat exchanger, a regenerator and at least one additional heat exchanger. The first stage Stirling thermal unit is serially coupled to a first end of a quarter wavelength long coupling tube. A second stage Stirling thermal unit comprising a main ambient heat exchanger, a regenerator, and at least one additional heat exchanger, is serially coupled to a second end of the quarter wavelength long coupling tube.

  13. Stirling engine or heat pump having an improved seal

    DOEpatents

    White, Maurice A.; Riggle, Peter; Emigh, Stuart G.

    1985-01-01

    A Stirling Engine or Heat Pump having two relatively movable machine elements for power transmission purposes includes a hermetic seal bellows interposed between the elements for separating a working gas from a pressure compensating liquid that balances pressure across the bellows to reduce bellows stress and to assure long bellows life. The volume of pressure compensating liquid displaced due to relative movement between the machine elements is minimized by enclosing the compensating liquid within a region exposed to portions of both machine elements at one axial end of a slidable interface presented between them by a clearance seal having an effective diameter of the seal bellows. Pressure equalization across the bellows is achieved by a separate hermetically sealed compensator including a movable enclosed bellows. The interior of the compensator bellows is in communication with one side of the seal bellows, and its exterior is in communication with the remaining side of the seal bellows. A buffer gas or additional liquid region can be provided at the remaining axial end of the clearnace seal, along with valved arrangements for makeup of liquid leakage through the clearance seal.

  14. Stirling engine external heat system design with heat pipe heater

    NASA Technical Reports Server (NTRS)

    Godett, Ted M.; Ziph, Benjamin

    1986-01-01

    This final report presents the conceptual design of a liquid fueled external heating system (EHS) and the preliminary design of a heat pipe heater for the STM-4120 Stirling cycle engine, to meet the Air Force mobile electric power (MEP) requirement for units in the range of 20 to 60 kW. The EHS design had the following constraints: (1) Packaging requirements limited the overall system dimensions to about 330 mm x 250 mm x 100 mm; (2) Heat flux to the sodium heat pipe evaporator was limited to an average of 100 kW/m and a maximum of 550 kW/m based on previous experience; and (3) The heat pipe operating temperature was specified to be 800 C based on heat input requirements of the STM4-120. An analysis code was developed to optimize the EHS performance parameters and an analytical development of the sodium heat pipe heater was performed; both are presented and discussed. In addition, construction techniques were evaluated and scale model heat pipe testing performed.

  15. Stirling engine: Available tools for long-life assessment

    NASA Technical Reports Server (NTRS)

    Halford, Gary R.; Bartolotta, Paul A.

    1991-01-01

    A review is presented for the durability approaches applicable to long-time life assessment of Stirling engine hot-section components. The crucial elements are experimental techniques for generating long-time materials property data (both monotonic and cyclic flow and failure properties); analytic representations of slow strain rate material stress-strain response characteristics (monotonic and cyclic constitutive relations) at high temperatures and low stresses and strains; analytic creep-fatigue-environmental interaction life prediction methods applicable to long lifetimes at high temperatures and small stresses and strains; and experimental verification of life predictions. Long-lifetime design criteria for materials of interest are woefully lacking. Designing against failures due to creep, creep-rupture, fatigue, environmental attack, and creep-fatigue-environmental interaction will require considerable extrapolation. Viscoplastic constitutive models and time-temperature parameters will have to be calibrated for the hot-section materials of interest. Analysis combined with limited verification testing in a short-time regime will be required to build confidence in long-lifetime durability models.

  16. Cascading Tesla Oscillating Flow Diode for Stirling Engine Gas Bearings

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger

    2012-01-01

    Replacing the mechanical check-valve in a Stirling engine with a micromachined, non-moving-part flow diode eliminates moving parts and reduces the risk of microparticle clogging. At very small scales, helium gas has sufficient mass momentum that it can act as a flow controller in a similar way as a transistor can redirect electrical signals with a smaller bias signal. The innovation here forces helium gas to flow in predominantly one direction by offering a clear, straight-path microchannel in one direction of flow, but then through a sophisticated geometry, the reversed flow is forced through a tortuous path. This redirection is achieved by using microfluid channel flow to force the much larger main flow into this tortuous path. While microdiodes have been developed in the past, this innovation cascades Tesla diodes to create a much higher pressure in the gas bearing supply plenum. In addition, the special shape of the leaves captures loose particles that would otherwise clog the microchannel of the gas bearing pads.

  17. Measurement of rod seal lubrication for Stirling engine

    NASA Technical Reports Server (NTRS)

    Krauter, A. I.

    1980-01-01

    The elastohydrodynamic behavior of sliding elastomeric seals for the Stirling engine, was analyzed using an experimental apparatus to determine the instantaneous oil film thickness throughout the cyclic reciprocating motion. Tests were conducted on two commercial elastomeric seals: a "T" seal (76 mm O.D. and 3.8 mm between backing rings) and an "O" ring (76 mm O.D. and 5.3 mm diameter). Testing conditions included seal durometers of 70 and 90, sliding velocities of 0.8, 2.0, and 3.6 m/s, and no pressure gradient across the seal. Both acrylic and aluminum cylinders were used. Measured oil film thickness profiles were compared to results of the elastohydrodynamic analysis. The comparison shows an overall qualitative agreement. Friction and oil leakage measurements were also made at these sliding speeds. The fluid used was a typical synthetic base automotive lubricant. It is concluded that this first time experimental analytical comparison for oil film thickness indicates the need for some improvements in the analytical model and in the experimental technique.

  18. The development of a free-piston Stirling engine power conversion system for multiple applications utilizing alternative fuel sources

    NASA Astrophysics Data System (ADS)

    Marusak, T. J.

    The thermodynamic and mechanical advantages of free-piston Stirling engines developed to date by NASA, and their future potential as small powerplants, are discussed. Applications include heat-pumps, mobile electric power systems, solar thermal electric power generation and multiple heat source-capability power systems. Existing prototypes have demonstrated engine efficiencies of 33% even at low output levels, and an advanced design capable of 40% efficiency and an output power of more than 3 kW is currently undergoing extensive testing.

  19. Stirling Engine Natural Gas Combustion Demonstration Program. Final report, October 1989-January 1991

    SciTech Connect

    Ernst, W.; Moryl, J.; Riecke, G.

    1991-02-01

    Fueled on natural gas, the Stirling engine is an inherently clean, quiet, and efficient engine. With increasing environmental concern for air quality and the increasingly more stringent requirements for low engine exhaust emissions, the Stirling engine may be an attractive alternative to internal combustion (IC) engines. The study has demonstrated that ultra low emissions can be attained with a Stirling-engine-driven electric generator configured to burn natural gas. Combustion parameters were optimized to produce the lowest possible exhaust emissions for a flame-type combustor without compromising overall engine thermal efficiency. A market application survey and manufacturing cost analysis indicate that a market opportunity potentially exists in the volumes needed to economically manufacture a newly designed Stirling engine (Mod III) for stationary applications and hybrid vehicles. The translation of such potential markets into actual markets does, however, pose difficult challenges as substantial investments are required. Also, the general acceptance of a new engine type by purchasers requires a considerable amount of time.

  20. Testing and performance characteristics of a 1-kW free piston Stirling engine

    NASA Technical Reports Server (NTRS)

    Schreiber, J.

    1983-01-01

    A 1 kW single cylinder free piston Stirling engine, configured as a research engine, was tested with helium working gas. The engine features a posted displacer and dashpot load. The test results show the engine power output and efficiency to be lower than those observed during acceptance tests by the manufacturer. Engine tests results are presented for operation at the two heater head temperatures and with two regenerator porosities, along with flow test results for the heat exchangers.

  1. Overview of NASA Lewis Research Center free-piston Stirling engine activities

    NASA Technical Reports Server (NTRS)

    Slaby, J. G.

    1984-01-01

    A generic free-piston Stirling technology project is being conducted to develop technologies generic to both space power and terrestrial heat pump applications in a cooperative, cost-shared effort. The generic technology effort includes extensive parametric testing of a 1 kW free-piston Stirling engine (RE-1000), development of a free-piston Stirling performance computer code, design and fabrication under contract of a hydraulic output modification for RE-1000 engine tests, and a 1000-hour endurance test, under contract, of a 3 kWe free-piston Stirling/alternator engine. A newly initiated space power technology feasibility demonstration effort addresses the capability of scaling a free-piston Stirling/alternator system to about 25 kWe; developing thermodynamic cycle efficiency or equal to 70 percent of Carnot at temperature ratios in the order of 1.5 to 2.0; achieving a power conversion unit specific weight of 6 kg/kWe; operating with noncontacting gas bearings; and dynamically balancing the system. Planned engine and component design and test efforts are described.

  2. Stirling engines. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    1995-02-01

    The bibliography contains citations concerning Stirling engine technology. Design, development, performance testing, and applications are discussed, including power generation, cryogenic cooling, solar power applications, and ground and marine vehicles. The citations also examine engine component design and material testing results. (Contains 250 citations and includes a subject term index and title list.)

  3. Stirling engines. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    Not Available

    1994-04-01

    The bibliography contains citations concerning Stirling engine technology. Design, development, performance testing, and applications are discussed, including power generation, cryogenic cooling, solar power applications, and ground and marine vehicles. The citations also examine engine component design and material testing results. (Contains 250 citations and includes a subject term index and title list.)

  4. Stirling engines. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    1996-05-01

    The bibliography contains citations concerning Stirling engine technology. Design, development, performance testing, and applications are discussed, including power generation, cryogenic cooling, solar power applications, and ground and marine vehicles. The citations also examine engine component design and material testing results. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  5. Initial Comparison of Single Cylinder Stirling Engine Computer Model Predictions with Test Results

    NASA Technical Reports Server (NTRS)

    Tew, R. C., Jr.; Thieme, L. G.; Miao, D.

    1979-01-01

    A Stirling engine digital computer model developed at NASA Lewis Research Center was configured to predict the performance of the GPU-3 single-cylinder rhombic drive engine. Revisions to the basic equations and assumptions are discussed. Model predictions with the early results of the Lewis Research Center GPU-3 tests are compared.

  6. Report on the 1. Techno Rally of small model cars driven by Stirling engines

    SciTech Connect

    Isshiki, N.; Hirata, M.; Fujii, I.; Masuno, M.

    1998-07-01

    The first speed contest of model cars driven by hand made Stirling engines was held in summer of 1997 in Tokyo under the name of The First Stirling Techno Rally sponsored by JSME and others. The body of cars were smaller than 60 cm in length and 30 cm in width to fit the test course and Stirling engines were non-pressurized hot air engine fueled by gas or solid fuel. On the race day, 103 cars were gathered from high schools, universities and companies, and the contest was successful1 in both technical and educational purposes. The top speed record was 4.25 second for 13 m run. In this paper the details of this contest are reported. The second techno rally will be held in November, 1998 at Honda's sub car test course.

  7. Stirling Space Engine Program. Volume 2; Appendixes A, B, C and D

    NASA Technical Reports Server (NTRS)

    Dhar, Manmohan

    1999-01-01

    The objective of this program was to develop the technology necessary for operating Stirling power converters in a space environment and to demonstrate this technology in full-scale engine tests. Volume 2 of the report includes the following appendices: Appendix A: Heater Head Development (Starfish Heater Head Program, 1/10th Segment and Full-Scale Heat Pipes, and Sodium Filling and Processing); Appendix B: Component Test Power Converter (CTPC) Component Development (High-temperature Organic Materials, Heat Exchanger Fabrication, Beryllium Issues, Sodium Issues, Wear Couple Tests, Pressure Boundary Penetrations, Heating System Heaters, and Cooler Flow Test); Appendix C: Udimet Testing (Selection of the Reference Material for the Space Stirling Engine Heater Head, Udimet 720LI Creep Test Result Update, Final Summary of Space Stirling Endurance Engine Udimet 720L1 Fatigue Testing Results, Udimet 720l1 Weld Development Summary, and Udimet 720L1 Creep Test Final Results Summary), and Appendix D: CTPC Component Development Photos.

  8. Overview of NASA Lewis Research Center free-piston Stirling engine technology activities applicable to space power systems

    NASA Technical Reports Server (NTRS)

    Slaby, J. G.

    1986-01-01

    Free piston Stirling technology is applicable for both solar and nuclear powered systems. As such, the Lewis Research Center serves as the project office to manage the newly initiated SP-100 Advanced Technology Program. This five year program provides the technology push for providing significant component and subsystem options for increased efficiency, reliability and survivability, and power output growth at reduced specific mass. One of the major elements of the program is the development of advanced power conversion concepts of which the Stirling cycle is a viable candidate. Under this program the research findings of the 25 kWe opposed piston Space Power Demonstrator Engine (SPDE) are presented. Included in the SPDE discussions are initial differences between predicted and experimental power outputs and power output influenced by variations in regenerators. Projections are made for future space power requirements over the next few decades. And a cursory comparison is presented showing the mass benefits that a Stirling system has over a Brayton system for the same peak temperature and output power.

  9. A Hemispherical-Involute Cavity Receiver for Stirling Engine Powered by a Xenon Arc Solar Simulator

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Gang; Tang, Da-Wei; Li, Tie; Du, Jing-Long

    2011-05-01

    We develop a solar simulator composed of multiple xenon arc lamps combined with a faceted paraboloidal dish concentrator to drive a Stirling engine in our laboratory for all-weather indoor testing. Experiments and numerical analysis are performed to determine the radiation flux and temperature distributions on the solar receiver surface. Based on the theoretical results, we present a receiver design for a solar Stirling engine with involute tubes closely conforming to the imaginary hemisphere to obtain a substantially uniform temperature field and a high solar-thermal efficiency of 67.1%.

  10. Development and utilization of new and renewable energy with Stirling engine system for electricity in China

    SciTech Connect

    Dong, W.; Abenavoli, R.I.; Carlini, M.

    1996-12-31

    China is the largest developing country in the world. Self-supporting and self-sustaining energy supply is the only solution for development. Recently, fast economic development exposed gradually increasing pressure of energy demand and environment concern. In order to increase the production of electricity of China, the Stirling engine system should be developed. This paper provides an investigation of energy production and consumption in China. The main features of the energy consumption and the development objectives of China`s electric power industry are also described. The necessity and possibility of development of Stirling engine system is discussed.

  11. Heat-activated heat-pump development and potential application of Stirling-engine technology

    NASA Astrophysics Data System (ADS)

    Fairchild, P. D.; West, C. D.

    1982-06-01

    Presented is a brief overview of the heat-activated heat pump technology development program being carried out with emphasis on the Stirling engine technology projects. The major projects are reviewed as they were formulated and carried out under the previous product development guidelines. The revised technology development focus and current status of those major hardware projects are discussed. The key issues involved in applying Stirling engine technology to heat pump equipment are assessed. The approach and planned future activities to address those issues are described. Also included are brief descriptions of two projects in this area supported by the Gas Research Institute.

  12. Evaluation of the potential of the Stirling engine for heavy duty application

    NASA Technical Reports Server (NTRS)

    Meijer, R. J.; Ziph, B.

    1981-01-01

    A 150 hp four cylinder heavy duty Stirling engine was evaluated. The engine uses a variable stroke power control system, swashplate drive and ceramic insulation. The sensitivity of the design to engine size and heater temperature is investigated. Optimization shows that, with porous ceramics, indicated efficiencies as high as 52% can be achieved. It is shown that the gain in engine efficiency becomes insignificant when the heater temperature is raised above 200 degrees F.

  13. Conceptual design and cost analysis of hydraulic output unit for 15 kW free-piston Stirling engine

    NASA Technical Reports Server (NTRS)

    White, M. A.

    1982-01-01

    A long-life hydraulic converter with unique features was conceptually designed to interface with a specified 15 kW(e) free-piston Stirling engine in a solar thermal dish application. Hydraulic fluid at 34.5 MPa (5000 psi) is produced to drive a conventional hydraulic motor and rotary alternator. Efficiency of the low-maintenance converter design was calculated at 93.5% for a counterbalanced version and 97.0% without the counterbalance feature. If the converter were coupled to a Stirling engine with design parameters more typcial of high-technology Stirling engines, counterbalanced converter efficiency could be increased to 99.6%. Dynamic computer simulation studies were conducted to evaluate performance and system sensitivities. Production costs of the complete Stirling hydraulic/electric power system were evaluated at $6506 which compared with $8746 for an alternative Stirling engine/linear alternator system.

  14. Single Phase Passive Rectification Versus Active Rectification Applied to High Power Stirling Engines

    NASA Technical Reports Server (NTRS)

    Santiago, Walter; Birchenough, Arthur G.

    2006-01-01

    Stirling engine converters are being considered as potential candidates for high power energy conversion systems required by future NASA explorations missions. These types of engines typically contain two major moving parts, the displacer and the piston, in which a linear alternator is attached to the piston to produce a single phase sinusoidal waveform at a specific electric frequency. Since all Stirling engines perform at low electrical frequencies (less or equal to 100 Hz), space explorations missions that will employ these engines will be required to use DC power management and distribution (PMAD) system instead of an AC PMAD system to save on space and weight. Therefore, to supply such DC power an AC to DC converter is connected to the Stirling engine. There are two types of AC to DC converters that can be employed, a passive full bridge diode rectifier and an active switching full bridge rectifier. Due to the inherent line inductance of the Stirling Engine-Linear Alternator (SE-LA), their sinusoidal voltage and current will be phase shifted producing a power factor below 1. In order to keep power the factor close to unity, both AC to DC converters topologies will implement power factor correction. This paper discusses these power factor correction methods as well as their impact on overall mass for exploration applications. Simulation results on both AC to DC converters topologies with power factor correction as a function of output power and SE-LA line inductance impedance are presented and compared.

  15. 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.

  16. 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.

  17. Performance Analysis of Stirling Engine-Driven Vapor Compression Heat Pump System

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru

    Stirling engine-driven vapor compression systems have many unique advantages including higher thermal efficiencies, preferable exhaust gas characteristics, multi-fuel usage, and low noise and vibration which can play an important role in alleviating environmental and energy problems. This paper introduces a design method for the systems based on reliable mathematical methods for Stirling and Rankin cycles using reliable thermophysical information for refrigerants. The model deals with a combination of a kinematic Stirling engine and a scroll compressor. Some experimental coefficients are used to formulate the model. The obtained results show the performance behavior in detail. The measured performance of the actual system coincides with the calculated results. Furthermore, the calculated results clarify the performance using alternative refrigerants for R-22.

  18. 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

  19. Development and demonstration of a Stirling/Rankine heat activated heat pump. Phase 3B: Engine technology development testing

    NASA Astrophysics Data System (ADS)

    1984-11-01

    The results of the Phase 3B Stirling/Rankine Heat Activated Heat Pump product development program are given. Results of the Phase 2 program indicated deficiencies in the performance of the free-piston Stirling engine and mismatching of the dynamic characteristics of the engine and the compressor. These deficiencies were further investigated during in-depth diagnostic testing of the engine/compressor unit in the Phase 3B and indicated appropriate engine/compressor matching criteria.

  20. Design and development of Stirling engines for stationary power generation applications in the 500 to 3000 horsepower range, volume 1

    NASA Astrophysics Data System (ADS)

    Schuetz, M.; Gerstmann, J.; Hoagland, L.; Syniuta, W.; Krisher, R.; Randall, C.

    1980-09-01

    The conceptual design and associated cost estimates of a stationary Stirling engine capable of being fueled by a variety of heat sources are discussed with emphasis on coal firing. The development and evaluation of conceptual designs are separated into two broad categories: the A designs which represent the present state-of-the-art and which are demonstrable by 1985 with minimum technical risk; and the B designs which involve advanced technology and therefore would require significant research and development prior to demonstration and commercialization, but which may ultimately offer advantages in terms of lower cost, better performance, or higher reliability.

  1. Development and test of combustion chamber for Stirling engine heated by natural gas

    NASA Astrophysics Data System (ADS)

    Li, Tie; Song, Xiange; Gui, Xiaohong; Tang, Dawei; Li, Zhigang; Cao, Wenyu

    2014-04-01

    The combustion chamber is an important component for the Stirling engine heated by natural gas. In the paper, we develop a combustion chamber for the Stirling engine which aims to generate 3˜5 kWe electric power. The combustion chamber includes three main components: combustion module, heat exchange cavity and thermal head. Its feature is that the structure can divide "combustion" process and "heat transfer" process into two apparent individual steps and make them happen one by one. Since natural gas can mix with air fully before burning, the combustion process can be easily completed without the second wind. The flame can avoid contacting the thermal head of Stirling engine, and the temperature fields can be easily controlled. The designed combustion chamber is manufactured and its performance is tested by an experiment which includes two steps. The experimental result of the first step proves that the mixture of air and natural gas can be easily ignited and the flame burns stably. In the second step of experiment, the combustion heat flux can reach 20 kW, and the energy utilization efficiency of thermal head has exceeded 0.5. These test results show that the thermal performance of combustion chamber has reached the design goal. The designed combustion chamber can be applied to a real Stirling engine heated by natural gas which is to generate 3˜5 kWe electric power.

  2. Start-up and control method and apparatus for resonant free piston Stirling engine

    DOEpatents

    Walsh, Michael M.

    1984-01-01

    A resonant free-piston Stirling engine having a new and improved start-up and control method and system. A displacer linear electrodynamic machine is provided having an armature secured to and movable with the displacer and having a stator supported by the Stirling engine housing in juxtaposition to the armature. A control excitation circuit is provided for electrically exciting the displacer linear electrodynamic machine with electrical excitation signals having substantially the same frequency as the desired frequency of operation of the Stirling engine. The excitation control circuit is designed so that it selectively and controllably causes the displacer electrodynamic machine to function either as a generator load to extract power from the displacer or the control circuit selectively can be operated to cause the displacer electrodynamic machine to operate as an electric drive motor to apply additional input power to the displacer in addition to the thermodynamic power feedback to the displacer whereby the displacer linear electrodynamic machine also is used in the electric drive motor mode as a means for initially starting the resonant free-piston Stirling engine.

  3. 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.

  4. Experimental and analytical tools for evaluation of Stirling engine rod seal behavior

    NASA Technical Reports Server (NTRS)

    Krauter, A. I.; Cheng, H. S.

    1979-01-01

    The first year of a two year experimental and analytical program is reported. The program is directed at the elastohydrodynamic behavior of sliding elastomeric rod seals for the Stirling engine. During the year, experimental and analytical tools were developed for evaluating seal leakage, seal friction, and the fluid film thickness at the seal/cylinder interface.

  5. Study on Operating Performance of Stirling Engine-Driven Vapor Compression Heat Pump System

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru

    Stirling engines have many unique advantages including higher thermal efficiencies, preferable exhaust gas characteristics, multi-fuel usage, and low noise and vibration. On the other hand, heat pump systems are very attractive for space heating and cooling, and industrial usage. There are several environmental merits of Stirling driven vapor compression (SDVC) systems. A design method for the SDVC, which is based on mathematical methods for Stirling and Ranking cycles, has been developed. The attractive SDVC performance using conventional and alternative refrigerants was shown. From the calculated Total Equivalent Warming Impact (TEWI) and operating costs, it became clear that the SDVC system with the alternative refrigerant has a higher potential as the future air-conditioning system.

  6. Heat Transfer and Fluid Dynamics Measurements in the Expansion Space of a Stirling Cycle Engine

    NASA Technical Reports Server (NTRS)

    Jiang, Nan; Simon, Terrence W.

    2006-01-01

    The heater (or acceptor) of a Stirling engine, where most of the thermal energy is accepted into the engine by heat transfer, is the hottest part of the engine. Almost as hot is the adjacent expansion space of the engine. In the expansion space, the flow is oscillatory, impinging on a two-dimensional concavely-curved surface. Knowing the heat transfer on the inside surface of the engine head is critical to the engine design for efficiency and reliability. However, the flow in this region is not well understood and support is required to develop the CFD codes needed to design modern Stirling engines of high efficiency and power output. The present project is to experimentally investigate the flow and heat transfer in the heater head region. Flow fields and heat transfer coefficients are measured to characterize the oscillatory flow as well as to supply experimental validation for the CFD Stirling engine design codes. Presented also is a discussion of how these results might be used for heater head and acceptor region design calculations.

  7. 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.

  8. Experimental and vector analysis on gamma type Stirling engine with hot power cylinder

    SciTech Connect

    Isshiki, Naotsugu; Tsukahara, Shigeji; Ohtomo, Michihiro

    1995-12-31

    In 1993, the superiority of hot end connected power cylinder gamma type Stirling engine (HEC) compared to the conventional cold end connected power cylinder engine (CEC) was reported by Prof. J.Kentfield of the University of Calgary. It is a great thing that he introduced the HEC engine, and it reminded the authors that in 1980, they built and experimented with a three cylinder 3kW Stirling engine SRI-1, in which two cylinders are positively heated by gas, that is called HCH (Hot, Cold and Hot) engine as shown in a figure, and having similarity to the above HEC. The authors have developed a quite simple and understandable approximate harmonic vector analysis method for Stirling machines. By this, Kentfield`s HEC engine and their HCH engine are expressed by the same figure as shown in the paper. The similarity and superiority of HEC and HCH compared to CEC and CHC are easily shown by the vector analysis method with physical reason.

  9. The construction of life prediction models for the design of Stirling engine heater components

    NASA Technical Reports Server (NTRS)

    Petrovich, A.; Bright, A.; Cronin, M.; Arnold, S.

    1983-01-01

    The service life of Stirling-engine heater structures of Fe-based high-temperature alloys is predicted using a numerical model based on a linear-damage approach and published test data (engine test data for a Co-based alloy and tensile-test results for both the Co-based and the Fe-based alloys). The operating principle of the automotive Stirling engine is reviewed; the economic and technical factors affecting the choice of heater material are surveyed; the test results are summarized in tables and graphs; the engine environment and automotive duty cycle are characterized; and the modeling procedure is explained. It is found that the statistical scatter of the fatigue properties of the heater components needs to be reduced (by decreasing the porosity of the cast material or employing wrought material in fatigue-prone locations) before the accuracy of life predictions can be improved.

  10. Comparative survey of dynamic analyses of free-piston stirling engines

    SciTech Connect

    Kankam, M.D.; Rauch, J.S.

    1994-09-01

    This paper compares reported dynamic analyses for evaluating the steady-state response and stability of free-piston Stirling engine (FPSE) systems. Various analytical approaches are discussed to provide guidance on their salient features. Recommendations are made in the recommendations remarks for an approach which captures most of the inherent properties of the engine. Such an approach has the potential for yielding results which will closely match practical FPSE-load systems.

  11. Comparative survey of dynamic analyses of free-piston Stirling engines

    NASA Technical Reports Server (NTRS)

    Kankam, M. David; Rauch, Jeffrey S.

    1991-01-01

    Reported dynamics analyses for evaluating the steady-state response and stability of free-piston Stirling engine (FPSE) systems are compared. Various analytical approaches are discussed to provide guidance on their salient features. Recommendations are made in the recommendations remarks for an approach which captures most of the inherent properties of the engine. Such an approach has the potential for yielding results which will closely match practical FPSE-load systems.

  12. Performance of the Vanguard Solar Dish-Stirling Engine Module. Final report

    SciTech Connect

    Droher, J.J.; Squier, S.E.

    1986-07-01

    This report summarizes information on the performance of the Vanguard Parabolic Dish/Stirling Engine Module during an 18-month period of operational testing (February 1984 through July 1985) at Rancho Mirage, California. The test module consisted of a 10.7-m-diameter parabolic dish to collect and concentrate solar beam radiation, a solar receiver, a four-cylinder Stirling engine using hydrogen as the working gas, an induction generator, and an air-cooled radiator. Historical beam insolation data are summarized for the Palm Springs area. Gross and net output of electricity, auxiliary power requirements, system availability, and capacity factors are summarized on a monthly and annual basis. Models are presented for predicting electrical output. Operating and maintenance experience is delineated chronologically and by subsystem. The performance of each major subsystem is discussed. An assessment is made of the present and future status of the dish/Stirling system. Recommendations are made for future developmental work involving dish/Stirling applications for the utility industry.

  13. A numerical simulation method and analysis of a complete thermoacoustic-Stirling engine.

    PubMed

    Ling, Hong; Luo, Ercang; Dai, Wei

    2006-12-22

    Thermoacoustic prime movers can generate pressure oscillation without any moving parts on self-excited thermoacoustic effect. The details of the numerical simulation methodology for thermoacoustic engines are presented in the paper. First, a four-port network method is used to build the transcendental equation of complex frequency as a criterion to judge if temperature distribution of the whole thermoacoustic system is correct for the case with given heating power. Then, the numerical simulation of a thermoacoustic-Stirling heat engine is carried out. It is proved that the numerical simulation code can run robustly and output what one is interested in. Finally, the calculated results are compared with the experiments of the thermoacoustic-Stirling heat engine (TASHE). It shows that the numerical simulation can agrees with the experimental results with acceptable accuracy.

  14. Conceptual design of 500 to 3000 hp Stirling engines for stationary power generation

    NASA Astrophysics Data System (ADS)

    Toscano, W. M.; Chandrasehkar, R.; Harvey, A. C.; Lee, K.

    Both near term and far term conceptual designs of a 373 kW (500 hp) to 2237 kW (3000 hp) Stirling engine for stationary power generation have been prepared. The recommended near term conceptual design is modular, consisting of a basic Stirling engine cylinder of 100 kW that is easily adaptable to any type of heat input or machine output. The engine output configuration selected is the single crank, narrow V, multicylinder arrangement in which any number of cylinders, in groups of four or five, provide the desired power rating. For clean fuel combustion, the prevaporized, premixed, combustion method with exhaust gas recirculation is employed. For coal combustion a Wormser Grate two-stage atmospheric fluidized bed combustion system with a high pressure gas circulation loop system is recommended. The predicted overall fuel to electrical energy conversion efficiency varied between 25 and 34 percent, depending on the system configuration.

  15. 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.

  16. A numerical model on thermodynamic analysis of free piston Stirling engines

    NASA Astrophysics Data System (ADS)

    Mou, Jian; Hong, Guotong

    2017-02-01

    In this paper, a new numerical thermodynamic model which bases on the energy conservation law has been used to analyze the free piston Stirling engine. In the model all data was taken from a real free piston Stirling engine which has been built in our laboratory. The energy conservation equations have been applied to expansion space and compression space of the engine. The equation includes internal energy, input power, output power, enthalpy and the heat losses. The heat losses include regenerative heat conduction loss, shuttle heat loss, seal leakage loss and the cavity wall heat conduction loss. The numerical results show that the temperature of expansion space and the temperature of compression space vary with the time. The higher regeneration effectiveness, the higher efficiency and bigger output work. It is also found that under different initial pressures, the heat source temperature, phase angle and engine work frequency pose different effects on the engine’s efficiency and power. As a result, the model is expected to be a useful tool for simulation, design and optimization of Stirling engines.

  17. Stirling engines for low-temperature solar-thermal-electric power generation

    NASA Astrophysics Data System (ADS)

    der Minassians, Artin

    This dissertation discusses the design and development of a distributed solar-thermal-electric power generation system that combines solar-thermal technology with a moderate-temperature Stirling engine to generate electricity. The conceived system incorporates low-cost materials and utilizes simple manufacturing processes. This technology is expected to achieve manufacturing cost of less than $1/W. Since solar-thermal technology is mature, the analysis, design, and experimental assessment of moderate-temperature Stirling engines is the main focus of this thesis. The design, fabrication, and test of a single-phase free-piston Stirling engine prototype is discussed. This low-power prototype is designed and fabricated as a test rig to provide a clear understanding of the Stirling cycle operation, to identify the key components and the major causes of irreversibility, and to verify corresponding theoretical models. As a component, the design of a very low-loss resonant displacer piston subsystem is discussed. The displacer piston is part of a magnetic circuit that provides both a required stiffness and actuation forces. The stillness is provided by a magnetic spring, which incorporates an array of permanent magnets and has a very linear stiffness characteristic that facilitates the frequency tuning. In this prototype, the power piston is not mechanically linked to the displacer piston and forms a mass-spring resonating subsystem with the engine chamber gas spring and has resonant frequency matched to that of the displacer. The fabricated engine prototype is successfully tested and the experimental results are presented and discussed. Extensive experimentation on individual component subsystems confirms the theoretical models and design considerations, providing a sound basis for higher power Stirling engine designs for residential or commercial deployments. Multi-phase Stirling engine systems are also considered and analyzed. The modal analysis of these machines proves

  18. Magnetic bearings for free-piston Stirling engines

    NASA Technical Reports Server (NTRS)

    Curwen, P. W.; Fleming, D. P.; Rao, D. K.; Wilson, D. S.

    1992-01-01

    The feasibility and efficacy of applying magnetic bearings to free-piston Stirling-cycle power conversion machinery currently being developed for long-term space missions are assessed. The study was performed for a 50-kWe Reference Stirling Space Power Converter (RSSPC) which currently uses hydrostatic gas bearings to support the reciprocating displacer and power piston assemblies. Active magnetic bearings of the attractive electromagnetic type are feasible for the RSSPC power piston. Magnetic support of the displacer assembly would require unacceptable changes to the design of the current RSSPC. However, magnetic suspension of both displacer and power piston is feasible for a relative-displacer version of the RSSPC. Magnetic suspension of the RSSPC power piston can potentially increase overall efficiency by 0.5 to 1 percent (0.1 to 0.3 efficiency points). Magnetic bearings will also overcome several operational concerns associated with hydrostatic gas bearing systems. These advantages, however, are accompanied by a 5 percent increase in specific mass of the RSSPC.

  19. 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.

  20. 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

    Objectives of this work are: (1) Assist the Science Mission Directorate in developing technologies for space missions. (2) Explore the capability of computational modeling to assist in the development of the Advanced Stirling Convertor. (3) Baseline computational simulation with available experimental data of the ASC. (4) Calculate peak external pressure vessel wall temperatures and compare them with anticipated values. (5) Calculated peak magnet temperature inside the ASC over a range of operational scenarios.

  1. Free-piston Stirling hydraulic engine and drive system for automobiles

    NASA Technical Reports Server (NTRS)

    Beremand, D. G.; Slaby, J. G.; Nussle, R. C.; Miao, D.

    1982-01-01

    The calculated fuel economy for an automotive free piston Stirling hydraulic engine and drive system using a pneumatic accumulator with the fuel economy of both a conventional 1980 spark ignition engine in an X body class vehicle and the estimated fuel economy of a 1984 spark ignition vehicle system are compared. The results show that the free piston Stirling hydraulic system with a two speed transmission has a combined fuel economy nearly twice that of the 1980 spark ignition engine - 21.5 versus 10.9 km/liter (50.7 versus 25.6 mpg) under comparable conditions. The fuel economy improvement over the 1984 spark ignition engine was 81 percent. The fuel economy sensitivity of the Stirling hydraulic system to system weight, number of transmission shifts, accumulator pressure ratio and maximum pressure, auxiliary power requirements, braking energy recovery, and varying vehicle performance requirements are considered. An important finding is that a multispeed transmission is not required. The penalty for a single speed versus a two speed transmission is about a 12 percent drop in combined fuel economy to 19.0 km/liter (44.7 mpg). This is still a 60 percent improvement in combined fuel economy over the projected 1984 spark ignition vehicle.

  2. The 25 kWe solar thermal Stirling hydraulic engine system: Conceptual design

    NASA Technical Reports Server (NTRS)

    White, Maurice; Emigh, Grant; Noble, Jack; Riggle, Peter; Sorenson, Torvald

    1988-01-01

    The conceptual design and analysis of a solar thermal free-piston Stirling hydraulic engine system designed to deliver 25 kWe when coupled to a 11 meter test bed concentrator is documented. A manufacturing cost assessment for 10,000 units per year was made. The design meets all program objectives including a 60,000 hr design life, dynamic balancing, fully automated control, more than 33.3 percent overall system efficiency, properly conditioned power, maximum utilization of annualized insolation, and projected production costs. The system incorporates a simple, rugged, reliable pool boiler reflux heat pipe to transfer heat from the solar receiver to the Stirling engine. The free-piston engine produces high pressure hydraulic flow which powers a commercial hydraulic motor that, in turn, drives a commercial rotary induction generator. The Stirling hydraulic engine uses hermetic bellows seals to separate helium working gas from hydraulic fluid which provides hydrodynamic lubrication to all moving parts. Maximum utilization of highly refined, field proven commercial components for electric power generation minimizes development cost and risk.

  3. 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.

  4. Solar power generation by use of Stirling engine and heat loss analysis of its cavity receiver

    NASA Astrophysics Data System (ADS)

    Hussain, Tassawar

    Since concentrated power generation by Stirling engine has the highest efficiency therefore efficient power generation by concentrated systems using a Stirling engine was a primary motive of this research. A 1 kW Stirling engine was used to generate solar power using a Fresnel lens as a concentrator. Before operating On-Sun test, engine's performance test was conducted by combustion test. Propane gas with air was used to provide input heat to the Stirling Engine and 350W power was generated with 14% efficiency of the engine. Two kinds of receivers were used for On-Sun test, first type was the Inconel tubes with trapped helium gas and the second one was the heat pipe. Heat pipe with sodium as a working fluid is considered the best approach to transfer the uniform heat from the receiver to the helium gas in the heater head of the engine. A Number of On-Sun experiments were performed to generate the power. A minimum 1kW input power was required to generate power from the Stirling engine but it was concluded that the available Fresnel lens was not enough to provide sufficient input to the Stirling engine and hence engine was lagged to generate the solar power. Later on, for a high energy input a Beam Down system was also used to concentrate the solar light on the heater head of the Stirling engine. Beam down solar system in Masdar City UAE, constructed in 2009 is a variation of central receiver plant with cassegrainian optics. Around 1.5kW heat input was achieved from the Beam Down System and it was predicted that the engine receiver at beam down has the significant heat losses of about 900W. These high heat losses were the major hurdles to get the operating temperature (973K) of the heat pipes; hence power could not be generated even during the Beam Down test. Experiments were also performed to find the most suitable Cavity Receiver configuration for maximum solar radiation utilizations by engine receiver. Dimensionless parameter aperture ration (AR=d/D) and aperture

  5. Influence of quantum degeneracy on the performance of a gas Stirling engine cycle

    NASA Astrophysics Data System (ADS)

    He, Ji-Zhou; Mao, Zhi-Yuan; Wang, Jian-Hui

    2006-09-01

    Based on the state equation of an ideal quantum gas, the regenerative loss of a Stirling engine cycle working with an ideal quantum gas is calculated. Thermal efficiency of the cycle is derived. Furthermore, under the condition of quantum degeneracy, several special thermal efficiencies are discussed. Ratios of thermal efficiencies versus the temperature ratio and volume ratio of the cycle are made. It is found that the thermal efficiency of the cycle not only depends on high and low temperatures but also on maximum and minimum volumes. In a classical gas state the thermal efficiency of the cycle is equal to that of the Carnot cycle. In an ideal quantum gas state the thermal efficiency of the cycle is smaller than that of the Carnot cycle. This will be significant for deeper understanding of the gas Stirling engine cycle.

  6. Electric co-generation units equipped with wood gasifier and Stirling engine

    SciTech Connect

    Bartolini, C.M.; Caresana, F.; Pelagalli, L.

    1998-07-01

    The disposal of industrial waste such as oil sludges, waste plastic, lubricant oils, paper and wood poses serious problems due to the ever increasing amount of material to be disposed of and to the difficulty in finding new dumping sites. The interest in energy recovery technologies is accordingly on the increase. In particular, large amounts of waste wood are simply burned or thrown away causing considerable environmental damage. In this context the co-generation technique represents one of the possible solutions for efficient energy conversion. The present paper proposes the employment of a Stirling engine as prime mover in a co-generation set equipped with a wood gasifier. A Stirling engine prototype previously developed in a joint project with Mase Generators, an Italian manufacturer of fixed and portable electrogenerators, is illustrated and its design is described.

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

    NASA Astrophysics Data System (ADS)

    Dochat, George R.; Dhar, Manmohan

    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.

  8. A two-dimensional model for the heat transfer on the external circuit of a Stirling engine for a dish/Stirling system

    SciTech Connect

    Makhkamov, K.K.; Ingham, D.B.

    1998-07-01

    In this paper the {kappa}-{var{underscore}epsilon} turbulent model for the incompressible fluid flow has been used to describe the heat transfer and gas dynamical processes on the external circuit of a Stirling Engine as used on a Solar Dish/Stirling System. The problem considered, in this work for a cavity-type heat receiver of the Stirling Engine, is that of the heat transfer in the body of the shell of the heat exchangers of the engine due to the thermal conductivity, the convective heat transfer between the working fluid and the walls of the engine internal gas circuit and the heat transfer due to the forced convection of the air in the cavity and in the attached air domain. The boundary conditions employed on the engines internal circuit were obtained using the developed one-dimensional second level mathematical model of the engine working cycle. Physical models for the distribution of the solar insolation on the bottom and side walls of the heat receiver have been taken into account and the temperature fields for the heat receiver and the air velocity have been obtained for the case when the heat receiver is affected by wind. The numerical results show that it is in the region of the boundary of the input window of the heat receiver where there is the largest reduction in the temperature in the shell of the heat exchangers and this is due to the convection of the air.

  9. Control scheme for power modulation of a free piston Stirling engine

    DOEpatents

    Dhar, Manmohan

    1989-01-01

    The present invention relates to a control scheme for power modulation of a free-piston Stirling engine-linear alternator power generator system. The present invention includes connecting an autotransformer in series with a tuning capacitance between a linear alternator and a utility grid to maintain a constant displacement to piston stroke ratio and their relative phase angle over a wide range of operating conditions.

  10. Pool boiler heat transport system for a 25 kWe advanced Stirling conversion system

    NASA Technical Reports Server (NTRS)

    Anderson, W. G.; Rosenfeld, J. H.; Saaski, E. L.; Noble, J.; Tower, L.

    1990-01-01

    Experiments to determine alkali metal/enhanced surface combinations that have stable boiling at the temperatures and heat fluxes that occur in the Stirling engine are reported. Two enhanced surfaces and two alkali metal working fluids were evaluated. The enhanced surfaces were an EDM hole covered surface and a sintered-powder-metal porous layer surface. The working fluids tested were potassium and eutectic sodium-potasium alloy (NaK), both with and without undissolved noncondensible gas. Noncondensible gas (He and Xe) was added to the system to provide gas in the nucleation sites, preventing quenching of the sites. The experiments demonstrated the potential of an alkali metal pool boiler heat transport system for use in a solar-powered Stirling engine. The most favorable fluid/surface combination tested was NaK boiling on a -100 +140 mesh 304L stainless steel sintered porous layer with no undissolved noncondensible gas. This combination provided stable, high-performance boiling at the operating temperature of 700 C. Heat fluxes into the system ranged from 10 to 50 W/sq cm. The transition from free convection to nucleate boiling occurred at temperatures near 540 C. Based on these experiments, a pool boiler was designed for a full-scale 25-kWe Stirling system.

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

    NASA Astrophysics Data System (ADS)

    Dochat, George R.; Dhar, Manmohan

    1991-01-01

    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.

  12. On the dynamical vs. thermodynamical performance of a β-type Stirling engine

    NASA Astrophysics Data System (ADS)

    Reséndiz-Antonio, Margarita; Santillán, Moisés

    2014-09-01

    In this work we present a simple mathematical model for a β-type Stirling engine. Despite its simplicity, the model considers all the engine’s relevant thermodynamic and mechanical aspects. The dynamic behavior of the model equation of motion is analyzed in order to obtain the sufficient conditions for engine cycling and to study the stability of the stationary regime. The performance of the engine’s thermodynamic part is also investigated. As a matter of fact, we found that it corresponds to a Carnot engine.

  13. Heat-pipe gas-combustion system endurance test for Stirling engine. Final report, May 1990-September 1990

    SciTech Connect

    Mahrle, P.

    1990-12-01

    Stirling Thermal Motors, Inc., (STM) has been developing a general purpose Heat Pipe Gas Combustion System (HPGC) suitable for use with the STM4-120 Stirling engine. The HPGC consists of a parallel plate recuperative preheater, a finned heat pipe evaporator and a film cooled gas combustor. A principal component of the HPGC is the heat pipe evaporator which collects and distributes the liquid sodium over the heat transfer surfaces. The liquid sodium evaporates and flows to the condensers where it delivers its latent heat. The report presents test results of endurance tests run on a Gas-Fired Stirling Engine (GFSE). Tests on a dynamometer test stand yielded 67 hours of engine operation at power levels over 10 kW (13.5 hp) with 26 hours at power levels above 15 kW (20 hp). Total testing of the engine, including both motoring tests and engine operation, yielded 245 hours of engine run time.

  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.

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Evaluation and Validation of Organic Materials for Advanced Stirling Convertors (ASCs): Overview

    NASA Technical Reports Server (NTRS)

    Shin, Euy-Sik Eugene

    2015-01-01

    Various organic materials are used as essential parts in Stirling Convertors for their unique properties and functionalities such as bonding, potting, sealing, thread locking, insulation, and lubrication. More efficient Advanced Stirling Convertors (ASC) are being developed for future space applications especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration or lunar surface power or Mars rovers, and others. Thus, performance, durability, and reliability of those organics should be critically evaluated in every possible material-process-fabrication-service environment relations based on their mission specifications. In general, thermal stability, radiation hardness, outgassing, and material compatibility of the selected organics have been systematically evaluated while their process and fabrication conditions and procedures were being optimized. Service environment-simulated long term aging tests up to 4 years were performed as a function of temperature for durability assessment of the most critical organic material systems.

  1. 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

  2. Advances in Tissue Engineering

    PubMed Central

    Vacanti, Joseph

    2016-01-01

    Nearly 30 years ago, we reported on a concept now known as Tissue Engineering. Here, we report on some of the advances in this now thriving area of research. In particular, significant advances in tissue engineering of skin, liver, spinal cord, blood vessels, and other areas are discussed. PMID:26711689

  3. Activity and accomplishments of dish/Stirling electric power system development

    NASA Technical Reports Server (NTRS)

    Livingston, F. R.

    1985-01-01

    The development of the solar parabolic-dish/Stirling-engine electricity generating plant known as the dish/Stirling electric power system is described. The dish/Stirling electric power system converts sunlight to electricity more efficiently than any known existing solar electric power system. The fabrication and characterization of the test bed concentrators that were used for Stirling module testing and of the development of parabolic dish concentrator No. 2, an advanced solar concentrator unit considered for use with the Stirling power conversion unit is discussed.

  4. Design and fabrication of a meso-scale stirling engine and combustor.

    SciTech Connect

    Echekki, Tarek (Sandia National Laboratories, Livermore, CA); Haroldsen, Brent L. (Sandia National Laboratories, Livermore, CA); Krafcik, Karen L. (Sandia National Laboratories, Livermore, CA); Morales, Alfredo Martin; Mills, Bernice E.; Liu, Shiling; Lee, Jeremiah C. (Sandia National Laboratories, Livermore, CA); Karpetis, Adionos N. (Sandia National Laboratories, Livermore, CA); Chen, Jacqueline H. (Sandia National Laboratories, Livermore, CA); Ceremuga, Joseph T. (Sandia National Laboratories, Livermore, CA); Raber, Thomas N.; Hekmuuaty, Michelle A.

    2005-05-01

    Power sources capable of supplying tens of watts are needed for a wide variety of applications including portable electronics, sensors, micro aerial vehicles, and mini-robotics systems. The utility of these devices is often limited by the energy and power density capabilities of batteries. A small combustion engine using liquid hydrocarbon fuel could potentially increase both power and energy density by an order of magnitude or more. This report describes initial development work on a meso-scale external combustion engine based on the Stirling cycle. Although other engine designs perform better at macro-scales, we believe the Stirling engine cycle is better suited to small-scale applications. The ideal Stirling cycle requires efficient heat transfer. Consequently, unlike other thermodynamic cycles, the high heat transfer rates that are inherent with miniature devices are an advantage for the Stirling cycle. Furthermore, since the Stirling engine uses external combustion, the combustor and engine can be scaled and optimized semi-independently. Continuous combustion minimizes issues with flame initiation and propagation. It also allows consideration of a variety of techniques to promote combustion that would be difficult in a miniature internal combustion engine. The project included design and fabrication of both the engine and the combustor. Two engine designs were developed. The first used a cylindrical piston design fabricated with conventional machining processes. The second design, based on the Wankel rotor geometry, was fabricated by through-mold electroforming of nickel in SU8 and LIGA micromolds. These technologies provided the requisite precision and tight tolerances needed for efficient micro-engine operation. Electroformed nickel is ideal for micro-engine applications because of its high strength and ductility. A rotary geometry was chosen because its planar geometry was more compatible with the fabrication process. SU8 lithography provided rapid

  5. Computer program for a four-cylinder-Stirling-engine controls simulation

    NASA Technical Reports Server (NTRS)

    Daniels, C. J.; Lorenzo, C. F.

    1982-01-01

    A four cylinder Stirling engine, transient engine simulation computer program is presented. The program is intended for controls analysis. The associated engine model was simplified to shorten computer calculation time. The model includes engine mechanical drive dynamics and vehicle load effects. The computer program also includes subroutines that allow: (1) acceleration of the engine by addition of hydrogen to the system, and (2) braking of the engine by short circuiting of the working spaces. Subroutines to calculate degraded engine performance (e.g., due to piston ring and piston rod leakage) are provided. Input data required to run the program are described and flow charts are provided. The program is modular to allow easy modification of individual routines. Examples of steady state and transient results are presented.

  6. Experimental characterization of a small custom-built double-acting gamma-type stirling engine

    NASA Astrophysics Data System (ADS)

    Intsiful, Peter; Mensah, Francis; Thorpe, Arthur

    This paper investigates characterization of a small custom-built double-acting gamma-type stirling engine. Stirling-cycle engine is a reciprocating energy conversion machine with working spaces operating under conditions of oscillating pressure and flow. These conditions may be due to compressibility as wells as pressure and temperature fluctuations. In standard literature, research indicates that there is lack of basic physics to account for the transport phenomena that manifest themselves in the working spaces of reciprocating engines. Previous techniques involve governing equations: mass, momentum and energy. Some authors use engineering thermodynamics. None of these approaches addresses this particular engine. A technique for observing and analyzing the behavior of this engine via parametric spectral profiles has been developed, using laser beams. These profiles enabled the generation of pv-curves and other trajectories for investigating the thermos-physical and thermos-hydrodynamic phenomena that manifest in the exchangers. The engine's performance was examined. The results indicate that with current load of 35.78A, electric power of 0.505 kW was generated at a speed of 240 rpm and 29.50 percent efficiency was obtained. Nasa grants to Howard University NASA/HBCU-NHRETU & CSTEA.

  7. The Development of a Control System for a 5 Kilowatt Free Piston Stirling Engine Convertor

    NASA Technical Reports Server (NTRS)

    Kirby, Raymond L.; Vitale, Nick

    2008-01-01

    The new NASA Vision for Exploration, announced by President Bush in January 2004, proposes an ambitious program that plans to return astronauts to the moon by the 2018 time frame. A recent NASA study entitled "Affordable Fission Surface Power Study" recommended a 40 kWe, 900 K, NaK-cooled, Stirling convertors for 2020 launch. Use of two of the nominal 5 kW convertors allows the system to be dynamically balanced. A group of four dual-convertor combinations that would yield 40 kWe can be tested to validate the viability of Stirling technology for space fission surface power systems. The work described in this paper deals specifically with the control system for the 5 kW convertor described in the preceding paragraph. This control system is responsible for maintaining piston stroke to a setpoint in the presence of various disturbances including electrical load variations. Pulse starting of the Free Piston Stirling Engine (FPSE) convertor is also an inherent part of such a control system. Finally, the ability to throttle the engine to match the required output power is discussed in terms of setpoint control. Several novel ideas have been incorporated into the piston stroke control strategy that will engender a stable response to disturbances in the presence of midpoint drift while providing useful data regarding the position of both the power piston and displacer.

  8. Design, fabrication, and testing of a sodium evaporator for the STM4-120 kinematic Stirling engine

    SciTech Connect

    Rawlinson, K.S.; Adkins, D.R.

    1995-05-01

    This report describes the development and testing of a compact heat-pipe heat exchanger kW(e) designed to transfer thermal energy from hot combustion gases to the heater tubes of a 25-kW(e) Stirling engine. In this system, sodium evaporates from a surface that is heated by a stream of hot gases. The liquid metal then condenses on the heater tubes of a Stirling engine, where energy is transferred to the engine`s helium working fluid. Tests on a prototype unit illustrated that a compact (8 cm {times} 13 cm {times} 16 cm) sodium evaporator can routinely transfer 15 kW(t) of energy at an operating vapor temperature of 760 C. Four of these prototype units were eventually used to power a 25-kW(e) Stirling engine system. Design details and test results from the prototype unit are presented in this report.

  9. Two-tiered design analysis of a radiator for a solar dynamic powered Stirling engine

    NASA Technical Reports Server (NTRS)

    Hainley, Donald C.

    1989-01-01

    Two separate design approaches for a pumped loop radiator used to transfer heat from the cold end of a solar dynamic powered Stirling engine are described. The first approach uses a standard method to determine radiator requirements to meet specified end of mission conditions. Trade-off studies conducted for the analysis are included. Justification of this concept within the specified parameters of the analysis is provided. The second design approach determines the life performance of the radiator/Stirling system. In this approach, the system performance was altered by reducing the radiator heat transfer area. Performance effects and equilibrium points were determined as radiator segments were removed. This simulates the effect of loss of radiator sections due to micro-meteoroid and space debris penetration. The two designs were compared on the basis of overall system requirements and goals.

  10. A 4-cylinder Stirling engine computer program with dynamic energy equations

    NASA Technical Reports Server (NTRS)

    Daniele, C. J.; Lorenzo, C. F.

    1983-01-01

    A computer program for simulating the steady state and transient performance of a four cylinder Stirling engine is presented. The thermodynamic model includes both continuity and energy equations and linear momentum terms (flow resistance). Each working space between the pistons is broken into seven control volumes. Drive dynamics and vehicle load effects are included. The model contains 70 state variables. Also included in the model are piston rod seal leakage effects. The computer program includes a model of a hydrogen supply system, from which hydrogen may be added to the system to accelerate the engine. Flow charts are provided.

  11. Electrical performances of pyroelectric bimetallic strip heat engines describing a Stirling cycle

    NASA Astrophysics Data System (ADS)

    Arnaud, A.; Boughaleb, J.; Monfray, S.; Boeuf, F.; Cugat, O.; Skotnicki, T.

    2015-12-01

    This paper deals with the analytical modeling of pyroelectric bimetallic strip heat engines. These devices are designed to exploit the snap-through of a thermo-mechanically bistable membrane to transform a part of the heat flowing through the membrane into mechanical energy and to convert it into electric energy by means of a piezoelectric layer deposited on the surface of the bistable membrane. In this paper, we describe the properties of these heat engines in the case when they complete a Stirling cycle, and we evaluate the performances (available energy, Carnot efficiency...) of these harvesters at the macro- and micro-scale.

  12. Experimental and theoretical analysis of the performance of Stirling engine with pendulum type displacer

    SciTech Connect

    Isshiki, Seita; Isshiki, Naotsugu; Takanose, Eiichiro; Igawa, Yoshiharu

    1995-12-31

    This paper describes the detailed experimental and theoretical performance of new type Stirling engine with pendulum type displacer (PDSE) which was proposed last year. This kind of engine has a pendulum type displacer suspended by the hinge shaft, and swings right and left in displacer space. The present paper mainly discusses the PDSE-3B which is an atmospheric 30[W] engine heated by fuel and cooled by water. It is clear that power required to provide a pendulum type displacer motion is expressed as a simple equation consisting of viscous flow loss term proportional to the square of rotational speed and dynamic pressure loss term proportional to the cube of rotational speed. It is also clear that theoretical engine power defined as the difference between experimental indicated power and power required to provide pendulum type displacer motion agrees well with the experimental engine power. It is also clear that measured Nusselt number of regenerator`s wire meshes agreed with the equation of previous study. In conclusion, PDSE is considered effective for measuring many aspects of performance of the Stirling engine.

  13. Proceedings of the 25th intersociety energy conversion engineering conference

    SciTech Connect

    Nelson, P.A.; Schertz, W.W.; Till, R.H.

    1990-01-01

    This book contains the proceedings of the 25th Intersociety Energy Conversion Engineering Conference. Volume 5 is organized under the following headings: Photovoltaics I, Photovoltaics II, Geothermal power, Thermochemical conversion of biomass, Energy from waste and biomass, Solar thermal systems for environmental applications, Solar thermal low temperature systems and components, Solar thermal high temperature systems and components, Wind systems, Space power sterling technology Stirling cooler developments, Stirling solar terrestrial I, Stirling solar terrestrial II, Stirling engine generator sets, Stirling models and simulations, Stirling engine analysis, Stirling models and simulations, Stirling engine analysis, Stirling engine loss understanding, Novel engine concepts, Coal conversion and utilization, Power cycles, MHD water propulsion I, Underwater vehicle powerplants - performance, MHD underwater propulsion II, Nuclear power, Update of advanced nuclear power reactor concepts.

  14. RE-1000 free-piston Stirling engine sensitivity test results. Final report

    SciTech Connect

    Schreiber, J.G.; Geng, S.M.; Lorenz, G.V.

    1986-10-01

    The NASA Lewis Research Center has been testing a 1 kW (1.33 hp) free-piston Stirling engine at the NASA Lewis test facilities. The tests performed over the past several years have been on a single cylinder machine known as the RE-1000. The data recorded were to aid in the investigation of the dynamics and thermodynamics of the free-piston Stirling engine. The data are intended to be used primarily for computer code validation. NASA reports TM-82999, TM-83407, and TM-87126 give initial results of the engine tests. The tests were designed to investigate the sensitivity of the engine performance to variations on the mean pressure of the working space, the working fluid used, heater and cooler temperatures, regenerator porosity, power piston mass and displacer dynamics. These tests have now been completed at NASA Lewis. This report presents some of the detailed data collected in the sensitivity tests. In all, 781 data points were recorded. A complete description of the engine and test facility is given. Many of the data can be found in tabular form, while a microfiche containing all of the data points can be requested from NASA Lewis.

  15. The design and fabrication of a Stirling engine heat exchanger module with an integral heat pipe

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    1988-01-01

    The conceptual design of a free-piston Stirling Space Engine (SSE) intended for space power applications has been generated. The engine was designed to produce 25 kW of electric power with heat supplied by a nuclear reactor. A novel heat exchanger module was designed to reduce the number of critical joints in the heat exchanger assembly while also incorporating a heat pipe as the link between the engine and the heat source. Two inexpensive verification tests are proposed. The SSE heat exchanger module is described and the operating conditions for the module are outlined. The design process of the heat exchanger modules, including the sodium heat pipe, is briefly described. Similarities between the proposed SSE heat exchanger modules and the LeRC test modules for two test engines are presented. The benefits and weaknesses of using a sodium heat pipe to transport heat to a Stirling engine are discussed. Similarly, the problems encountered when using a true heat pipe, as opposed to a more simple reflux boiler, are described. The instruments incorporated into the modules and the test program are also outlined.

  16. Alloy chemistry and microstructural control to meet the demands of the automotive Stirling engine

    NASA Technical Reports Server (NTRS)

    Stephens, Joseph R.

    1988-01-01

    The automotive Stirling engine now under development by DOE/NASA as an alternative to the internal combustion engine, imposes severe materials requirements for the hot portion of the engine. Materials selected must be low cost and contain a minimum of strategic elements so that availability is not a problem. Heater head tubes contain high pressure hydrogen on the inside and are exposed to hot combustion gases on the outside surface. The cylinders and regenerator housings must be readily castable into complex shapes having varying wall thicknesses and be amenable to brazing and welding operations. Also, high strength, oxidation resistance, resistance to hydrogen permeation, cyclic operation, and long-life are required. A research program conducted by NASA Lewis focused on alloy chemistry and microstructural control to achieve the desired properties over the life of the engine. Results of alloy selection, characterization, evaluation, and actual engine testing of selected materials are presented.

  17. Alloy chemistry and microstructural control to meet the demands of the automotive Stirling engine

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.

    1986-01-01

    The automotive Stirling engine now under development by DOE/NASA as an alternative to the internal combustion engine, imposes severe materials requirements for the hot portion of the engine. Materials selected must be low cost and contain a minimum of strategic elements so that availability is not a problem. Heater head tubes contain high pressure hydrogen on the inside and are exposed to hot combustion gases on the outside surface. The cylinders and regenerator housings must be readily castable into complex shapes having varying wall thicknesses and be amenable to brazing and welding operations. Also, high strength, oxidation resistance, resistance to hydrogen permeation, cyclic operation, and long-life are required. A research program conducted by NASA Lewis focused on alloy chemistry and microstructural control to achieve the desired properties over the life of the engine. Results of alloy selection, characterization, evaluation, and actual engine testing of selected materials are presented.

  18. Stirling engines. December 1976-April 1990 (A Bibliography from the COMPENDEX data base). Report for December 1976-April 1990

    SciTech Connect

    Not Available

    1990-05-01

    This bibliography contains citations concerning Stirling engine technology. Design, development, performance testing, and applications are discussed. Use in power generation, artificial heart systems, solar powered applications, and ground and marine vehicles are presented. Engine component design and material testing results are discussed. (This updated bibliography contains 280 citations, 58 of which are new entries to the previous edition.)

  19. 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.

  20. Advanced Engineering Fibers.

    ERIC Educational Resources Information Center

    Edie, Dan D.; Dunham, Michael G.

    1987-01-01

    Describes Clemson University's Advanced Engineered Fibers Laboratory, which was established to provide national leadership and expertise in developing the processing equipment and advance fibers necessary for the chemical, fiber, and textile industries to enter the composite materials market. Discusses some of the laboratory's activities in…

  1. Advanced engine study program

    NASA Technical Reports Server (NTRS)

    Masters, A. I.; Galler, D. E.; Denman, T. F.; Shied, R. A.; Black, J. R.; Fierstein, A. R.; Clark, G. L.; Branstrom, B. R.

    1993-01-01

    A design and analysis study was conducted to provide advanced engine descriptions and parametric data for space transfer vehicles. The study was based on an advanced oxygen/hydrogen engine in the 7,500 to 50,000 lbf thrust range. Emphasis was placed on defining requirements for high-performance engines capable of achieving reliable and versatile operation in a space environment. Four variations on the expander cycle were compared, and the advantages and disadvantages of each were assessed. Parametric weight, envelope, and performance data were generated over a range of 7,500 to 50,000 lb thrust and a wide range of chamber pressure and nozzle expansion ratio.

  2. A thermoacoustic-Stirling heat engine: Detailed study

    SciTech Connect

    Backhaus, S.; Swift, G. W.

    2000-06-01

    A new type of thermoacoustic engine based on traveling waves and ideally reversible heat transfer is described. Measurements and analysis of its performance are presented. This new engine outperforms previous thermoacoustic engines, which are based on standing waves and intrinsically irreversible heat transfer, by more than 50%. At its most efficient operating point, it delivers 710 W of acoustic power to its resonator with a thermal efficiency of 0.30, corresponding to 41% of the Carnot efficiency. At its most powerful operating point, it delivers 890 W to its resonator with a thermal efficiency of 0.22. The efficiency of this engine can be degraded by two types of acoustic streaming. These are suppressed by appropriate tapering of crucial surfaces in the engine and by using additional nonlinearity to induce an opposing time-averaged pressure difference. Data are presented which show the nearly complete elimination of the streaming convective heat loads. Analysis of these and other irreversibilities show which components of the engine require further research to achieve higher efficiency. Additionally, these data show that the dynamics and acoustic power flows are well understood, but the details of the streaming suppression and associated heat convection are only qualitatively understood. (c) 2000 Acoustical Society of America.

  3. A thermoacoustic-Stirling heat engine: detailed study

    PubMed

    Backhaus; Swift

    2000-06-01

    A new type of thermoacoustic engine based on traveling waves and ideally reversible heat transfer is described. Measurements and analysis of its performance are presented. This new engine outperforms previous thermoacoustic engines, which are based on standing waves and intrinsically irreversible heat transfer, by more than 50%. At its most efficient operating point, it delivers 710 W of acoustic power to its resonator with a thermal efficiency of 0.30, corresponding to 41% of the Carnot efficiency. At its most powerful operating point, it delivers 890 W to its resonator with a thermal efficiency of 0.22. The efficiency of this engine can be degraded by two types of acoustic streaming. These are suppressed by appropriate tapering of crucial surfaces in the engine and by using additional nonlinearity to induce an opposing time-averaged pressure difference. Data are presented which show the nearly complete elimination of the streaming convective heat loads. Analysis of these and other irreversibilities show which components of the engine require further research to achieve higher efficiency. Additionally, these data show that the dynamics and acoustic power flows are well understood, but the details of the streaming suppression and associated heat convection are only qualitatively understood.

  4. 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

  5. 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.

  6. Controllability of Free-piston Stirling Engine/linear Alternator Driving a Dynamic Load

    NASA Technical Reports Server (NTRS)

    Kankam, M. David; Rauch, Jeffrey S.

    1994-01-01

    This paper presents the dynamic behavior of a Free-Piston Stirling Engine/linear alternator (FPSE/LA) driving a single-phase fractional horse-power induction motor. The controllability and dynamic stability of the system are discussed by means of sensitivity effects of variations in system parameters, engine controller, operating conditions, and mechanical loading on the induction motor. The approach used expands on a combined mechanical and thermodynamic formulation employed in a previous paper. The application of state-space technique and frequency domain analysis enhances understanding of the dynamic interactions. Engine-alternator parametric sensitivity studies, similar to those of the previous paper, are summarized. Detailed discussions are provided for parametric variations which relate to the engine controller and system operating conditions. The results suggest that the controllability of a FPSE-based power system is enhanced by proper operating conditions and built-in controls.

  7. Hostile environmental conditions facing candidate alloys for the automotive Stirling engine

    SciTech Connect

    Stephens, J.R.

    1981-01-01

    A materials research program is underway at NASA Lewis Research Center in support of the DOE/NASA Automotive Stirling Engine Project. The program focuses on the hot heater head of the engine including the heater head tubes, cylinders, and regenerator housings, which are considered to be the most critical components from a materials viewpoint. The specific areas of investigation in the progam involve hydrogen permeability testing, doping of the hydrogen working fluid to reduce permeability rates, oxidation/corrosion studies, creep-rupture evaluation, and assessing effects of hydrogen environment on mechanical properties. Recent results in each of the aforementioned areas of research are described. Special emphasis is placed on the materials challenges that result from the use of hydrogen as the working fluid in this potential alternative engine to today's internal combustion engines.

  8. Closed form analysis of a gamma, back-to-back free displacer Stirling engine

    SciTech Connect

    Lewis, K.L.; Kilgour, D.B.; Lazarides, Y.G.; Rallis, C.J.

    1983-08-01

    A back-to-back, free displacer, gamma type Stirling engine has been designed and is currently under manufacture and development at the University of the Witwatersrand. This paper presents a simple idealized analysis for such an engine. It involves the coupling together of the thermodynamic and mechanical equations, and by the use of classical control and vibration theory, closed form solutions are obtained. This work follows up on previous methods of analysis developed by Berchowitz, WyattMair and Goldberg for similar types of engines. A numerical application of the analysis has been carried out for the design in order to evaluate the operating frequency, phase displacements, amplitude of oscillation and basic output power. Performance characteristics are obtained and detailed in the paper. The analysis has provided analytic proof of the viability of the proposed engine configuration, highlighted weak areas and provided a background to higher order analysis. A programme of experimental validation is under way.

  9. The performance of a high-frequency thermoacoustic-Stirling engine

    NASA Astrophysics Data System (ADS)

    Bastyr, Kevin J.; Keolian, Robert M.

    2003-10-01

    A thermoacoustic-Stirling engine that operates at 400 Hz with a working fluid of 1-MPa helium is constructed. For proper acoustic phasing in this engine's regenerator, an acoustic power feedback path exists in the form of an annulus surrounding the regenerator. This feedback path is obtained by suspending an insulated, stainless steel sleeve containing a wire mesh regenerator, which is flanked by two heat exchangers, a short distance from one end of the larger diameter resonator. The ambient heat exchanger is a shell and tube exchanger, while the hot heater consists of nichrome ribbon wound on an aluminum silicate frame. Gedeon streaming is prevented by a diaphragm covering the end of the stainless steel sleeve adjacent to the ambient heat exchanger. A variable acoustic load provides a convenient means of testing this engine at various hot heater temperatures, while operating at different acoustic pressure amplitudes effects the acoustic power generated by the engine. [Work supported by ONR.

  10. Materials technology assessment for a 1050 K Stirling Space Engine design

    SciTech Connect

    Scheuermann, C.M.; Dreshfield, R.L.; Gaydosh, D.J.; Kiser, J.D.; MacKay, R.A.; McDanels, D.L.; Petrasek, D.W.; Vannucci, R.D.; Bowles, K.J.; Watson, G.K.

    1988-10-01

    An assessment of materials technology and proposed materials selection was made for the 1050 K (superalloy) Stirling Space Engine design. The objectives of this assessment were to evaluate previously proposed materials selections, evaluate the current state-of-the-art materials, propose potential alternate materials selections and identify research and development efforts needed to provide materials that can meet the stringent system requirements. This assessment generally reaffirmed the choices made by the contractor; however, in many cases alternative choices were described and suggestions for needed materials and fabrication research and development were made.

  11. Materials technology assessment for a 1050 K Stirling space engine design

    NASA Technical Reports Server (NTRS)

    Scheuermann, Coulson M.; Dreshfield, Robert L.; Gaydosh, Darrell J.; Kiser, James D.; Mackay, Rebecca A.; Mcdaniels, David L.; Petrasek, Donald W.; Vannucci, Raymond D.; Bowles, Kenneth J.; Watson, Gordon K.

    1988-01-01

    An assessment of materials technology and proposed materials selection was made for the 1050 K (superalloy) Stirling Space Engine design. The objectives of this assessment were to evaluate previously proposed materials selections, evaluate the current state-of-the-art materials, propose potential alternate materials selections and identify research and development efforts needed to provide materials that can meet the stringent system requirements. This assessment generally reaffirmed the choices made by the contractor. However, in many cases alternative choices were described and suggestions for needed materials and fabrication research and development were made.

  12. On the dynamic response of pressure transmission lines in the research of helium-charged free piston Stirling engines

    NASA Technical Reports Server (NTRS)

    Miller, Eric L.; Dudenhoefer, James E.

    1989-01-01

    In free piston Stirling engine research the integrity of both amplitude and phase of the dynamic pressure measurements is critical to the characterization of cycle dynamics and thermodynamics. It is therefore necessary to appreciate all possible sources of signal distortion when designing pressure measurement systems for this type of research. The signal distortion inherent to pressure transmission lines is discussed. Based on results from classical analysis, guidelines are formulated to describe the dynamic response properties of a volume-terminated transmission tube for applications involving helium-charged free piston Stirling engines. The scope and limitations of the dynamic response analysis are considered.

  13. RE-1000 free-piston Stirling engine hydraulic output system description

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Geng, Steven M.

    1987-01-01

    The NASA Lewis Research Center was involved in free-piston Stirling engine research since 1976. Most of the work performed in-house was related to characterization of the RE-1000 engine. The data collected from the RE-1000 tests were intended to provide a data base for the validation of Stirling cycle simulations. The RE-1000 was originally build with a dashpot load system which did not convert the output of the engine into useful power, but was merely used as a load for the engine to work against during testing. As part of the interagency program between NASA Lewis and the Oak Ridge National Laboratory, (ORNL), the RE-1000 was converted into a configuration that produces useable hydraulic power. A goal of the hydraulic output conversion effort was to retain the same thermodynamic cycle that existed with the dashpot loaded engine. It was required that the design must provide a hermetic seal between the hydraulic fluid and the working gas of the engine. The design was completed and the hardware was fabricated. The RE-1000 was modified in 1985 to the hydraulic output configuration. The early part of the RE-1000 hydraulic output program consisted of modifying hardware and software to allow the engine to run at steady-state conditions. A complete description of the engine is presented in sufficient detail so that the device can be simulated on a computer. Tables are presented showing the masses of the oscillating components and key dimensions needed for modeling purposes. Graphs are used to indicate the spring rate of the diaphragms used to separate the helium of the working and bounce space from the hydraulic fluid.

  14. Free-piston Stirling engine conceptual design and technologies for space power, phase 1

    NASA Technical Reports Server (NTRS)

    Penswick, L. Barry; Beale, William T.; Wood, J. Gary

    1990-01-01

    As part of the SP-100 program, a phase 1 effort to design a free-piston Stirling engine (FPSE) for a space dynamic power conversion system was completed. SP-100 is a combined DOD/DOE/NASA program to develop nuclear power for space. This work was completed in the initial phases of the SP-100 program prior to the power conversion concept selection for the Ground Engineering System (GES). Stirling engine technology development as a growth option for SP-100 is continuing after this phase 1 effort. Following a review of various engine concepts, a single-cylinder engine with a linear alternator was selected for the remainder of the study. The relationships of specific mass and efficiency versus temperature ratio were determined for a power output of 25 kWe. This parametric study was done for a temperature ratio range of 1.5 to 2.0 and for hot-end temperatures of 875 K and 1075 K. A conceptual design of a 1080 K FPSE with a linear alternator producing 25 kWe output was completed. This was a single-cylinder engine designed for a 62,000 hour life and a temperature ratio of 2.0. The heat transport systems were pumped liquid-metal loops on both the hot and cold ends. These specifications were selected to match the SP-100 power system designs that were being evaluated at that time. The hot end of the engine used both refractory and superalloy materials; the hot-end pressure vessel featured an insulated design that allowed use of the superalloy material. The design was supported by the hardware demonstration of two of the component concepts - the hydrodynamic gas bearing for the displacer and the dynamic balance system. The hydrodynamic gas bearing was demonstrated on a test rig. The dynamic balance system was tested on the 1 kW RE-1000 engine at NASA Lewis.

  15. Overview of the 1986 free-piston Stirling activities at NASA Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Alger, Donald L.

    1986-01-01

    An overview of the NASA Lewis Research Center's free-piston Stirling engine research is presented, including efforts to improve and advance its design for use in specific space power applications. These efforts are a part of the SP-100 program being conducted to support the Department of Defense (DOD), Department of Energy (DOE) and NASA. Such efforts include: (1) the testing and improvement of 25 kWe Stirling Space Power Demonstrator Engine (SPDE); (2) the preliminary design of 25 kWe single-cylinder Experimental stirling Space Engine (ESSE); and, (3) a study to determine the feasibility of scaling a single-cylinder free-piston Stirling engine/linear alternator to 150 kWe. Other NASA Lewis free-piston Stirling engine activities will be described, directed toward the advancement of general free-piston Stirling engine technology and its application in specific terrestrial applications. One such effort, supported by DOE/Oak Ridge National Laboratory (DRNL), is the development of a free-piston Stirling engine which produces hydraulic power. Finally, a terrestrial solar application involving a conceptual design of a 25 kWe Solar Advanced Stirling Conversion System (ASCS) capable of delivering power to an electric utility grid will be discussed. The latter work is supported by DOE/Sandia National Laboratory (SNLA).

  16. 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.

  17. Dynamically balanced, hydraulically driven compressor/pump apparatus for resonant free piston Stirling engines

    SciTech Connect

    Corey, John A.

    1984-05-29

    A compressor, pump, or alternator apparatus is designed for use with a resonant free piston Stirling engine so as to isolate apparatus fluid from the periodically pressurized working fluid of the Stirling engine. The apparatus housing has a first side closed by a power coupling flexible diaphragm (the engine working member) and a second side closed by a flexible diaphragm gas spring. A reciprocally movable piston is disposed in a transverse cylinder in the housing and moves substantially at right angles relative to the flexible diaphragms. An incompressible fluid fills the housing which is divided into two separate chambers by suitable ports. One chamber provides fluid coupling between the power diaphragm of the RFPSE and the piston and the second chamber provides fluid coupling between the gas spring diaphragm and the opposite side of the piston. The working members of a gas compressor, pump, or alternator are driven by the piston. Sealing and wearing parts of the apparatus are mounted at the external ends of the transverse cylinder in a double acting arrangement for accessibility. An annular counterweight is mounted externally of the reciprocally movable piston and is driven by incompressible fluid coupling in a direction opposite to the piston so as to damp out transverse vibrations.

  18. Rolling Thunder -- Integration of the Solo 161 Stirling engine with the CPG-460 solar concentrator at Ft. Huachuca

    SciTech Connect

    Diver, R.B.; Moss, T.A.; Goldberg, V.; Thomas, G.; Beaudet, A.

    1998-09-01

    Project Rolling Thunder is a dish/Stirling demonstration project at Ft. Huachuca, a US Army fort in southeastern Arizona (Huachuca means rolling thunder in Apache). It has been supported by the Strategic Environmental Research and Development Program (SERDP), a cooperative program between the Department of Defense (DoD) and the Department of Energy (DOE). As part of a 1992 SERDP project, Cummins Power Generation, Inc. (CPG) installed a CPG 7 kW(c) dish/Stirling system at the Joint Interoperability Test Command (JITC) in Ft. Huachuca, Arizona. The primary objective of the SERDP Dish/Stirling for DoD Applications project was to demonstrate a CPG 7-kW(c) dish/Stirling system at a military facility. Unfortunately, Cummins Engine Company decided to divest its solar operations. As a direct result of Ft. Huachuca`s interest in the Cummins dish/Stirling technology, Sandia explored the possibility of installing a SOLO 161 Stirling power conversion unit (PCU) on the Ft. Huachuca CPG-460. In January 1997, a decision was made to retrofit a SOLO 161 Stirling engine on the CPG-460 at Ft. Huachuca. Project Rolling Thunder. The SOLO 161 Demonstration at Ft. Huachuca has been a challenge. Although, the SOLO 161 PCU has operated nearly flawlessly and the CPG-460 has been, for the most part, a solid and reliable component, integration of the SOLO PCU with the CPG-460 has required significant attention. In this paper, the integration issues and technical approaches of project Rolling Thunder are presented. Lessons of the project are also discussed.

  19. 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.

  20. Overview of NASA Lewis Research Center free-piston Stirling engine technology activities applicable to space power systems

    NASA Astrophysics Data System (ADS)

    Slaby, Jack G.

    A brief overview is presented of the development and technological activities of the free-piston Stirling engine. The engine started as a small scale fractional horsepower engine which demonstrated basic engine operating principles and the advantages of being hermetically sealed, highly efficient, and simple. It eventually developed into the free piston Stirling engine driven heat pump, and then into the SP-100 Space Reactor Power Program from which came the Space Power Demonstrator Engine (SPDE). The SPDE successfully operated for over 300 hr and delivered 20 kW of PV power to an alternator plunger. The SPDE demonstrated that a dynamic power conversion system can, with proper design, be balanced; and the engine performed well with externally pumped hydrostatic gas bearings.

  1. Overview of NASA Lewis Research Center free-piston Stirling engine technology activities applicable to space power systems

    NASA Technical Reports Server (NTRS)

    Slaby, Jack G.

    1987-01-01

    A brief overview is presented of the development and technological activities of the free-piston Stirling engine. The engine started as a small scale fractional horsepower engine which demonstrated basic engine operating principles and the advantages of being hermetically sealed, highly efficient, and simple. It eventually developed into the free piston Stirling engine driven heat pump, and then into the SP-100 Space Reactor Power Program from which came the Space Power Demonstrator Engine (SPDE). The SPDE successfully operated for over 300 hr and delivered 20 kW of PV power to an alternator plunger. The SPDE demonstrated that a dynamic power conversion system can, with proper design, be balanced; and the engine performed well with externally pumped hydrostatic gas bearings.

  2. Stirling engines for solar power generation in the 50 to 500 kW range

    NASA Astrophysics Data System (ADS)

    Wells, D.; Percival, W.; Bratt, C.; Rosenqvist, K.; Berntell, J.

    Qualitative analyses are presented of solar Stirling power modules in terms of the engines, the concentrators, and the interaction between the size and efficiency of the modules with the cost of the system. A test unit with a parabolic dish concentrator has furnished 31.6 kWe using an 1800 rpm, 93% efficient permanent magnet alternator. Operating temperatures were 750 C, and engine efficiencies reached 38%. Point focus parabolic dishes, tracking heliostats, and stationary concentrators with tracking receivers are being examined. The engine cost has been projected to be only a small part of the total unit cost in mass production, and parabolic dishes are the lowest-cost configuration for manufacturing. Enclosing the dishes in greenhouses can lessen erosion of the surfaces. Foamglass has been identified as the most cost-effective concentrator material. Design alternatives for a 50-500 kW power array are described.

  3. Evaluation of Potential Military Applications of Stirling Engines

    DTIC Science & Technology

    1988-07-01

    have not been successful. D. REMOTELY PILOTED UNDERWATER VEHICLES The military need for small submarines ranges from tethered unmanned submersibles ...then lead-acid batteries are able to meet most mission propulsion requirements. For example, a hypothetical submersible 2 meters in diameter and 10... submersible and less than 8 percent of its volume. More advanced batteries (for example, silver/zinc or lithium thionyl chloride batteries) could

  4. Advancing cardiovascular tissue engineering

    PubMed Central

    Truskey, George A.

    2016-01-01

    Cardiovascular tissue engineering offers the promise of biologically based repair of injured and damaged blood vessels, valves, and cardiac tissue. Major advances in cardiovascular tissue engineering over the past few years involve improved methods to promote the establishment and differentiation of induced pluripotent stem cells (iPSCs), scaffolds from decellularized tissue that may produce more highly differentiated tissues and advance clinical translation, improved methods to promote vascularization, and novel in vitro microphysiological systems to model normal and diseased tissue function. iPSC technology holds great promise, but robust methods are needed to further promote differentiation. Differentiation can be further enhanced with chemical, electrical, or mechanical stimuli. PMID:27303643

  5. 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.

  6. Two-dimensional numerical simulation of a Stirling engine heat exchanger

    SciTech Connect

    Ibrahim, M.B.; Tew, R.C.; Dudenhoefer, J.E.

    1994-09-01

    This paper describes the first phase of an effort to develop multidimensional models of Stirling engine components; the ultimate goal is to model an entire engine working space. More specifically, this paper describes parallel plate and tubular heat exchanger models with emphasis on the central part of the channel (i.e., ignoring hydrodynamic and thermal end effects). The model assumes: Laminar, incompressible flow with constant thermophysical properties. In addition, a constant axial temperature gradient is imposed. The governing equations, describing the model, have been solved Crack-Nicloson finite-difference scheme. Model predictions have been compared with analytical solutions for oscillating/reversing flow and heat transfer in order to check numerical accuracy. The simplifying assumptions will later be relaxed to permit modeling of incompressible, laminar/turbulent flow that occurs in Stirling heat exchanger. Excellent agreement has been obtained for the model predictions with analytical solutions available for both flow in circular tubes and between parallel plates. Also the heat transfer computational results are in good agreement with the heat transfer analytical results for parallel plates.

  7. Multi-objective optimization and design for free piston Stirling engines based on the dimensionless power

    NASA Astrophysics Data System (ADS)

    Mou, Jian; Hong, Guotong

    2017-02-01

    In this paper, the dimensionless power is used to optimize the free piston Stirling engines (FPSE). The dimensionless power is defined as a ratio of the heat power loss and the output work. The heat power losses include the losses of expansion space, heater, regenerator, cooler and the compression space and every kind of the heat loss calculated by empirical formula. The output work is calculated by the adiabatic model. The results show that 82.66% of the losses come from the expansion space and 54.59% heat losses of expansion space come from the shuttle loss. At different pressure the optimum bore-stroke ratio, heat source temperature, phase angle and the frequency have different values, the optimum phase angles increase with the increase of pressure, but optimum frequencies drop with the increase of pressure. However, no matter what the heat source temperature, initial pressure and frequency are, the optimum ratios of piston stroke and displacer stroke all about 0.8. The three-dimensional diagram is used to analyse Stirling engine. From the three-dimensional diagram the optimum phase angle, frequency and heat source temperature can be acquired at the same time. This study offers some guides for the design and optimization of FPSEs.

  8. 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.

  9. Simulation of the instantaneous free piston Stirling engine-electrical load interaction

    SciTech Connect

    Mehdizadeh, N.S.; Stouffs, P.

    1998-07-01

    In this paper the authors consider a gamma type free piston engine (that is, a configuration with a power piston cylinder and a separate displacer cylinder) with the MARTINI configuration (that is, with a free piston but a kinematically driven displacer). In the modeled engine, the displacer is driven by an electrical motor and there are two symmetrical, free, power pistons. This configuration ensures a complete balancing of the engine. The free pistons bear the moving parts of the linear electric alternators. This engine may be considered for solar to electrical energy conversion for land or space applications, for instance. A dynamic simulation of this engine has been developed using a decoupled analysis. The motion equation of the free piston induces a strong coupling between the electrical load and the thermodynamics inside the free piston Stirling engine. From the thermodynamics point of view, the piston-displacer phase lag is an important parameter. It is shown that if the electrical circuit elements (R-L-C) are constants, the phase lag between the free pistons and displacer motions is far from the optimum. However this phase lag can be controlled by means of a variable electrical resistance. For both cases of stand-alone engine with an independent electrical load, or grid-connected engine, it is shown how one can in a very simple way multiply the net electrical power by a factor 4 to 10 and the efficiency by a factor 1.25 to 2 without any engine geometry modification.

  10. Alkali metal pool boiler life tests for a 25 kWe advanced Stirling conversion system

    NASA Technical Reports Server (NTRS)

    Anderson, W. G.; Rosenfeld, J. H.; Noble, J.

    1991-01-01

    The overall operating temperature and efficiency of solar-powered Stirling engines can be improved by adding an alkali metal pool boiler heat transport system to supply heat more uniformly to the heater head tubes. One issue with liquid metal pool boilers is unstable boiling. Stable boiling is obtained with an enhanced boiling surface containing nucleation sites that promote continuous boiling. Over longer time periods, it is possible that the boiling behavior of the system will change. An 800-h life test was conducted to verify that pool boiling with the chosen fluid/surface combination remains stable as the system ages. The apparatus uses NaK boiling on a - 100 + 140 stainless steel sintered porous layer, with the addition of a small amount of xenon. Pool boiling remained stable to the end of life test. The pool boiler life test included a total of 82 cold starts, to simulate startup each morning, and 60 warm restarts, to simulate cloud cover transients. The behavior of the cold and warm starts showed no significant changes during the life test. In the experiments, the fluid/surface combination provided stable, high-performance boiling at the operating temperature of 700 C. Based on these experiments, a pool boiler was designed for a full-scale 25-kWe Stirling system.

  11. CFD Modeling of Free-Piston Stirling Engines

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir B.; Zhang, Zhi-Guo; Tew, Roy C., Jr.; Gedeon, David; Simon, Terrence W.

    2001-01-01

    NASA Glenn Research Center (GRC) is funding Cleveland State University (CSU) to develop a reliable Computational Fluid Dynamics (CFD) code that can predict engine performance with the goal of significant improvements in accuracy when compared to one-dimensional (1-D) design code predictions. The funding also includes conducting code validation experiments at both the University of Minnesota (UMN) and CSU. In this paper a brief description of the work-in-progress is provided in the two areas (CFD and Experiments). Also, previous test results are compared with computational data obtained using (1) a 2-D CFD code obtained from Dr. Georg Scheuerer and further developed at CSU and (2) a multidimensional commercial code CFD-ACE+. The test data and computational results are for (1) a gas spring and (2) a single piston/cylinder with attached annular heat exchanger. The comparisons among the codes are discussed. The paper also discusses plans for conducting code validation experiments at CSU and UMN.

  12. Advanced Stirling Radioisotope Generator: Design Processes, Reliability Analyses Impacts, and Extended Operation Tests

    NASA Astrophysics Data System (ADS)

    Ha, Chuong T.; Fernandez, René; Cornford, Steven L.; Feather, Martin S.

    2008-01-01

    NASA is currently funding an effort involving the Department of Energy (DOE), Lockheed Martin (LM), Glenn Research Center (GRC), and Sunpower (SP), Inc. to develop a high specific power Advanced Stirling Radioisotope Generator (ASRG). GRC and SP are responsible for providing the Stirling convertor, while LM is responsible for the generator housing, controller, and system integration. GRC also provides supporting technologies for various components as well as extended operation testing, both in air and in a thermal vacuum environment. Because of the 17-year life requirement of the ASRG, reliability considerations are the main design driver. Components such as the heater head, fasteners, magnets, and planar spring have been studied to ensure high reliability. To encompass unique design features, long lifetimes and extreme environmental conditions, both reliability analyses and qualification tests are used to support the design process. This paper presents an overview of the ASRG reliability approach and the impact of the Reliability Working Group (RWG) on the recently finished design effort. It also provides a summary of current and planned extended operation tests, specifically targeted to demonstrate long-life capability and to support further reliability assessment. In the event of no, or minimal failures during these extended tests, a Weibayes approach will be used to create a trend of improving reliability predictions.

  13. Free-piston Stirling engine/linear alternator 1000-hour endurance test

    NASA Technical Reports Server (NTRS)

    Rauch, J.; Dochat, G.

    1985-01-01

    The Free Piston Stirling Engine (FPSE) has the potential to be a long lived, highly reliable, power conversion device attractive for many product applications such as space, residential or remote site power. The purpose of endurance testing the FPSE was to demonstrate its potential for long life. The endurance program was directed at obtaining 1000 operational hours under various test conditions: low power, full stroke, duty cycle and stop/start. Critical performance parameters were measured to note any change and/or trend. Inspections were conducted to measure and compare critical seal/bearing clearances. The engine performed well throughout the program, completing more than 1100 hours. Hardware inspection, including the critical clearances, showed no significant change in hardware or clearance dimensions. The performance parameters did not exhibit any increasing or decreasing trends. The test program confirms the potential for long life FPSE applications.

  14. Efficient protocols for Stirling heat engines at the micro-scale

    NASA Astrophysics Data System (ADS)

    Muratore-Ginanneschi, Paolo; Schwieger, Kay

    2015-10-01

    We investigate the thermodynamic efficiency of sub-micro-scale Stirling heat engines operating under the conditions described by overdamped stochastic thermodynamics. We show how to construct optimal protocols such that at maximum power the efficiency attains for constant isotropic mobility the universal law η=2 ηC/(4-ηC) , where ηC is the efficiency of an ideal Carnot cycle. We show that these protocols are specified by the solution of an optimal mass transport problem. Such solution can be determined explicitly using well-known Monge-Ampère-Kantorovich reconstruction algorithms. Furthermore, we show that the same law describes the efficiency of heat engines operating at maximum work over short time periods. Finally, we illustrate the straightforward extension of these results to cases when the mobility is anisotropic and temperature dependent.

  15. Analysis of the working process and mechanical losses in a Stirling engine for a solar power unit

    SciTech Connect

    Makhkamov, K.K.; Ingham, D.B.

    1999-05-01

    In this paper a second level mathematical model for the computational simulation of the working process of a 1-kW Stirling engine has been used and the results obtained are presented. The internal circuit of the engine in the calculation scheme was divided into five chambers, namely, the expansion space, heater, regenerator, cooler and the compression space, and the governing system of ordinary differential equations for the energy and mass conservation were solved in each chamber by Euler`s method. In addition, mechanical losses in the construction of the engine have been determined and the computational results show that the mechanical losses for this particular design of the Stirling engine may be up to 50% of the indicated power of the engine.

  16. Effects of sudden expansion and contraction flow on pressure drops in the Stirling engine regenerator

    SciTech Connect

    Hamaguchi, K.; Yamashita, I.; Hirata, K.

    1998-07-01

    The flow losses in the regenerators greatly influence the performance of the Stirling engine. The losses mainly depend on fluid friction through the regenerator matrix, but are also generated in sudden expansion and contraction flow at the regenerator ends. The latter losses can't be neglected in the case of small area ratio (entrance area/cross-sectional area in regenerator). The pressure drops in regenerators are usually estimated assuming a uniform velocity distribution of working gas in the matrices. The estimation results, however, are generally smaller than practical data. The cross-sectional flow areas of the heater and cooler of typical Stirling engines are smaller than the cross- sectional area of the regenerator. The effects of the small flow passage on the velocity distribution of working fluid in the matrix, that is, a flow transition from tubes or channels to a regenerator matrix, can be often confirmed by the discolored matrix. Especially, the lack of a uniform distribution of velocity in the matrix causes increased flow loss and decreased thermal performance. So, it is necessary to understand the quantitative effects of the sudden change in flow area at the regenerator ends on the velocity distribution and pressure drop. In this paper, using matrices made of stacks of wire screens, the effects of the entrance and exit areas and the length of the regenerator on pressure drops are examined by an unidirectional steady flow apparatus. The experimental data are arranged in an empirical equation. The lack of a uniformity of velocity distribution is visualized using smoke-wire methods. The empirical equation presented is applied to the estimation of pressure loss in an actual engine regenerator. The applicability of the equation is examined by comparison of estimated value with engine data in pressure loss.

  17. Multi-bottle, no compressor, mean pressure control system for a Stirling engine

    DOEpatents

    Corey, John A.

    1990-01-01

    The invention relates to an apparatus for mean pressure control of a Stirling engine without the need for a compressor. The invention includes a multi-tank system in which there is at least one high pressure level tank and one low pressure level tank wherein gas flows through a maximum pressure and supply line from the engine to the high pressure tank when a first valve is opened until the maximum pressure of the engine drops below that of the high pressure tank opening an inlet regulator to permit gas flow from the engine to the low pressure tank. When gas flows toward the engine it flows through the minimum pressure supply line 2 when a second valve is opened from the low pressure tank until the tank reaches the engine's minimum pressure level at which time the outlet regulator opens permitting gas to be supplied from the high pressure tank to the engine. Check valves between the two tanks prevent any backflow of gas from occurring.

  18. Technical and economic study of Stirling and Rankine cycle bottoming systems for heavy truck diesel engines

    NASA Technical Reports Server (NTRS)

    Kubo, I.

    1987-01-01

    Bottoming cycle concepts for heavy duty transport engine applications were studied. In particular, the following tasks were performed: (1) conceptual design and cost data development for Stirling systems; (2) life-cycle cost evaluation of three bottoming systems - organic Rankine, steam Rankine, and Stirling cycles; and (3) assessment of future directions in waste heat utilization research. Variables considered for the second task were initial capital investments, fuel savings, depreciation tax benefits, salvage values, and service/maintenance costs. The study shows that none of the three bottoming systems studied are even marginally attractive. Manufacturing costs have to be reduced by at least 65%. As a new approach, an integrated Rankine/Diesel system was proposed. It utilizes one of the diesel cylinders as an expander and capitalizes on the in-cylinder heat energy. The concept eliminates the need for the power transmission device and a sophisticated control system, and reduces the size of the exhaust evaporator. Results of an economic evaluation indicate that the system has the potential to become an attractive package for end users.

  19. Integration of Americium Heat Source into the Advanced Stirling Radioisotope Generator

    NASA Astrophysics Data System (ADS)

    Schulze, Erich; Quinn, Richard

    2014-08-01

    The Lockheed Martin developed Advanced Stirling Radioisotope Generator (ASRG) design uses similar technology as proposed for the European Space Agency (ESA) Radioisotope Power System (RPS) development program but different isotopes. The RPS uses americium, 241Am isotope, while the ASRG uses plutonium, 238Pu isotope. The 238Pu isotope provides four times greater thermal output per kilogram than the 241Am isotope. Lockheed Martin performed an internally funded feasibility assessment that determined integration of a 241Am fueled heat source into the ASRG is achievable with no changes to ASRG technology and only structural and volumetric design considerations required. Lockheed Martin is interested in developing collaborative partnerships with the United Kingdom (UK) for the ESA RPS development program.

  20. 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.

  1. A new chromium carbide-based tribological coating for use to 900 C with particular reference to the Stirling engine

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1986-01-01

    A new chromium carbide-based coating (PS 200) is described. This coating is shown to have good friction and wear properties over a wide temperature range. A nickel alloy-bonded chromium carbide coating was used as a baseline material for comparison with experimentally formulated coatings. Coatings were plasma sprayed onto metal disks, then diamond ground to a thickness of 0.025 cm. Friction and wear were determined using a pin on disk tribometer at temperatures from 25 to 900 C in hydrogen, helium, and air. Pin materials included several metallic alloys and silicon carbide. It was found that appropriate additions of metallic silver and of barium fluoride/calcium fluoride eutectic to the baseline carbide composition significantly reduced friction coefficients while preserving, and in some cases, even enhancing wear resistance. The results of this study demonstrate that PS 200 is a promising coating composition to consider for high temperature aerospace and advanced heat engine applications. The excellent results in hydrogen make this coating of particular interest for use in the Stirling engine.

  2. 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.

  3. 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.

  4. Advanced Stirling Convertor (ASC-E2) Performance Testing at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore; Wilson, Scott

    2011-01-01

    The National Aeronautics and Space Administration (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, four pairs of ASCs capable of operating to 850 C and designated with the model number ASC-E2, were delivered by Sunpower of Athens, Ohio, to GRC in 2010. The ASC-E2s underwent a series of tests that included workmanship vibration testing, performance mapping, and extended operation. Workmanship vibration testing was performed following fabrication of each convertor to verify proper hardware build. Performance mapping consisted of operating each convertor at various conditions representing the range expected during a mission. Included were conditions representing beginning-of-mission (BOM), end-of-mission (EOM), and fueling. This same series of tests was performed by Sunpower prior to ASC-E2 delivery. The data generated during the GRC test were compared to performance before delivery. Extended operation consisted of a 500-hr period of operation with conditions maintained at the BOM point. This was performed to demonstrate steady convertor performance following performance mapping. Following this initial 500-hr period, the ASC-E2s will continue extended operation, controller development and special durability testing, during which the goal is to accumulate tens of thousands of hours of operation. Data collected during extended operation will support reliability analysis. Performance data from these tests is summarized in this paper.

  5. Advanced Stirling Convertor (ASC-E2) Performance Testing at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore; Wilson, Scott

    2011-01-01

    The National Aeronautics and Space Administration (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, four pairs of ASCs capable of operating to 850 C and designated with the model number ASC-E2, were delivered by Sunpower of Athens, OH, to GRC in 2010. The ASC-E2s underwent a series of tests that included workmanship vibration testing, performance mapping, and extended operation. Workmanship vibration testing was performed following fabrication of each convertor to verify proper hardware build. Performance mapping consisted of operating each convertor at various conditions representing the range expected during a mission. Included were conditions representing beginning-of-mission (BOM), end-of-mission (EOM), and fueling. This same series of tests was performed by Sunpower prior to ASC-E2 delivery. The data generated during the GRC test were compared to performance before delivery. Extended operation consisted of a 500-hour period of operation with conditions maintained at the BOM point. This was performed to demonstrate steady convertor performance following performance mapping. Following this initial 500-hour period, the ASC-E2s will continue extended operation, controller development and special durability testing, during which the goal is to accumulate tens of thousands of hours of operation. Data collected during extended operation will support reliability analysis. Performance data from these tests is summarized in this paper.

  6. 3kW Stirling engine for power and heat production

    SciTech Connect

    Thorsen, J.E.; Bovin, J.; Carlsen, H.

    1996-12-31

    A new 3 kW Beta type Stirling engine has been developed. The engine uses Natural gas as fuel, and it is designed for use as a small combined heat and power plant for single family houses. The electrical power is supplied to the grid. The engine is made as a hermetic device, where the crank mechanism and the alternator are built into a pressurized crank casing. The engine produce 3 kW of shaft power corresponding to 2.4 kW of electric power. The heat input is 10 kW corresponding to a shaft efficiency of 30%, and an electric efficiency of 24%. Helium at 8 MPa mean pressure is used as working gas. The crank mechanism is a combination of an upper- and lower yoke, each forming the half of a Ross mechanism. The upper yoke is linked to the displacer piston and the lower yoke is linked to the working piston. The design gives an approximately linear couple point curve, which eliminates guiding forces on the pistons and the need for X-heads. Grease lubricated needle and ball bearings are used in the kinematic crank mechanism. The burner includes an air preheater and a water jacket, which makes it possible to utilize nearly all of the heat from the combustion gases. The performance of the engine has been tested as a function of mean pressure and hot and cold temperature, and emissions and noise have been measured.

  7. Design and development of Stirling engines for stationary power generation applications in the 500 to 3000 horsepower range. Volume 1. Technical report

    SciTech Connect

    Not Available,

    1980-09-15

    This project was Phase I of a multiphased program for the design and development of Stirling engines for stationary power generation applications in the 500 to 3000 horsepower range. Phase I comprised the conceptual design and associated cost estimates of a stationary Stirling engine capable of being fueled by a variety of heat sources, with emphasis on coal firing, followed by the preparation of a plan for implementing the design, fabrication and testing of a demonstration engine by 1985. The development and evaluation of conceptual designs have been separated into two broad categories: the A designs which represent the present state-of-the-art and which are demonstrable by 1985 with minimum technical risk; and the B designs which involve advanced technology and therefore would require significant research and development prior to demonstration and commercialization, but which may ultimately offer advantages in terms of lower cost, better performance, or higher reliability. The majority of the effort in Phase I was devoted to the A designs.

  8. Sodium heat pipe solar receiver for a SPS V-160 Stirling engine - Development, laboratory and on-sun test results

    NASA Astrophysics Data System (ADS)

    Laing, Doerte; Goebel, Olaf

    The design, laboratory tests, and on-sun tests of a heat pipe solar receiver for a Stirling Power Systems V-160 Stirling engine are reported. The heat-pipe-receiver-Stirling-engine unit has been tested successfully in the laboratory using an electrical radiant heater as a power source. Four different operating temperatures of the helium working gas from 625 C to 730 C have been tested. A steady-state performance evaluation was done for all four temperatures. Machine efficiencies (Stirling plus generator) at full power of 27 percent to 30 percent have been determined. Transient, start up and shut down behavior have been studied. Later the unit has been tested successfully in a 7.5 m diameter parabolic dish with an operating temperature of 700 C, where 8 kW net electric power output at 930 W/sq m with an aperture diameter of 120 mm have been reached. The receiver efficiency was about 83 percent at full power. The vapor temperature in the heat pipe was 40 K to 80 K above the operating temperature of the helium, depending on the power. Clear days with insolation levels up to 930 W/sq m as well as cloud passages at high insolation levels and startup from low temperature have been performed without heat pipe failure.

  9. Ideal thermodynamic processes of oscillatory-flow regenerative engines will go to ideal stirling cycle?

    NASA Astrophysics Data System (ADS)

    Luo, Ercang

    2012-06-01

    This paper analyzes the thermodynamic cycle of oscillating-flow regenerative machines. Unlike the classical analysis of thermodynamic textbooks, the assumptions for pistons' movement limitations are not needed and only ideal flowing and heat transfer should be maintained in our present analysis. Under such simple assumptions, the meso-scale thermodynamic cycles of each gas parcel in typical locations of a regenerator are analyzed. It is observed that the gas parcels in the regenerator undergo Lorentz cycle in different temperature levels, whereas the locus of all gas parcels inside the regenerator is the Ericson-like thermodynamic cycle. Based on this new finding, the author argued that ideal oscillating-flow machines without heat transfer and flowing losses is not the Stirling cycle. However, this new thermodynamic cycle can still achieve the same efficiency of the Carnot heat engine and can be considered a new reversible thermodynamic cycle under two constant-temperature heat sinks.

  10. A Microfabricated Segmented-Involute-Foil Regenerator for Enhancing Reliability and Performance of Stirling Engines

    NASA Technical Reports Server (NTRS)

    Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gadeon, David; Qiu, Songgang; Wood, Gary; Kelly, Kevin; McLean, Jeffrey

    2007-01-01

    An actual-size microfabricated regenerator comprised of a stack of 42 disks, 19 mm diameter and 0.25 mm thick, with layers of microscopic, segmented, involute-shaped flow channels was fabricated and tested. The geometry resembles layers of uniformly-spaced segmented-parallel-plates, except the plates are curved. Each disk was made from electro-plated nickel using the LiGA process. This regenerator had feature sizes close to those required for an actual Stirling engine but the overall regenerator dimensions were sized for the NASA/Sunpower oscillating-flow regenerator test rig. Testing in the oscillating-flow test rig showed the regenerator performed extremely well, significantly better than currently used random-fiber material, producing the highest figures of merit ever recorded for any regenerator tested in that rig over its approximately 20 years of use.

  11. Independently variable phase and stroke control for a double acting Stirling engine

    DOEpatents

    Berchowitz, David M.

    1983-01-01

    A phase and stroke control apparatus for the pistons of a Stirling engine includes a ring on the end of each piston rod in which a pair of eccentrics is arranged in series, torque transmitting relationship. The outer eccentric is rotatably mounted in the ring and is rotated by the orbiting ring; the inner eccentric is mounted on an output shaft. The two eccentrics are mounted for rotation together within the ring during normal operation. A device is provided for rotating one eccentric with respect to another to change the effective eccentricity of the pair of eccentrics. A separately controlled phase adjustment is provided to null the phase change introduced by the change in the orientation of the outer eccentric, and also to enable the phase of the pistons to be changed independently of the stroke change.

  12. Testing of reciprocating seals for application in a Stirling cycle engine

    NASA Technical Reports Server (NTRS)

    Curulla, J. F.; Beck, T. L.

    1980-01-01

    Six single stage reciprocating seal configurations to the requirements of the Stirling cycle engine were evaluated. The seals tested were: the Boeing Footseal, NASA Chevron polyimide seal, Bell seal, Quad seal, Tetraseal, and Dynabak seal. None of these seal configurations met the leakage goals of .002 cc/sec at helium gas pressure of 1.22 x 10 to the 7th power PA, rod speed of 7.19 m/sec peak, and seal environmental temperature of 408 K for 1500 hours. Most seals failed due to high temperatures. Catastrophic failures were observed for a minimum number of test runs characterized by extremely high leakage rates and large temperature rises. The Bell seal attained 63 hours of run time at significantly lowered test conditions.

  13. Initial comparison of single cylinder Stirling engine computer model predictions with test results

    NASA Technical Reports Server (NTRS)

    Tew, R. C., Jr.; Thieme, L. G.; Miao, D.

    1979-01-01

    A NASA developed digital computer code for a Stirling engine, modelling the performance of a single cylinder rhombic drive ground performance unit (GPU), is presented and its predictions are compared to test results. The GPU engine incorporates eight regenerator/cooler units and the engine working space is modelled by thirteen control volumes. The model calculates indicated power and efficiency for a given engine speed, mean pressure, heater and expansion space metal temperatures and cooler water inlet temperature and flow rate. Comparison of predicted and observed powers implies that the reference pressure drop calculations underestimate actual pressure drop, possibly due to oil contamination in the regenerator/cooler units, methane contamination in the working gas or the underestimation of mechanical loss. For a working gas of hydrogen, the predicted values of brake power are from 0 to 6% higher than experimental values, and brake efficiency is 6 to 16% higher, while for helium the predicted brake power and efficiency are 2 to 15% higher than the experimental.

  14. Development of free-piston Stirling engine performance and optimization codes based on Martini simulation technique

    NASA Technical Reports Server (NTRS)

    Martini, William R.

    1989-01-01

    A FORTRAN computer code is described that could be used to design and optimize a free-displacer, free-piston Stirling engine similar to the RE-1000 engine made by Sunpower. The code contains options for specifying displacer and power piston motion or for allowing these motions to be calculated by a force balance. The engine load may be a dashpot, inertial compressor, hydraulic pump or linear alternator. Cycle analysis may be done by isothermal analysis or adiabatic analysis. Adiabatic analysis may be done using the Martini moving gas node analysis or the Rios second-order Runge-Kutta analysis. Flow loss and heat loss equations are included. Graphical display of engine motions and pressures and temperatures are included. Programming for optimizing up to 15 independent dimensions is included. Sample performance results are shown for both specified and unconstrained piston motions; these results are shown as generated by each of the two Martini analyses. Two sample optimization searches are shown using specified piston motion isothermal analysis. One is for three adjustable input and one is for four. Also, two optimization searches for calculated piston motion are presented for three and for four adjustable inputs. The effect of leakage is evaluated. Suggestions for further work are given.

  15. Advances in thermal engineering

    SciTech Connect

    Kitto, J.B.; Fiveland, W.A.; Latham, C.E.; Peterson, G.P.

    1995-03-01

    Heat transfer--more broadly, thermal engineering--is playing an increasingly critical role in the development and successful application of advanced technology in virtually all fields. From space stations to hazardous-waste destruction to high-speed transport, from ozone-protecting refrigerants to ``night vision`` goggles, a vast range of technologies depend on energy management, heat-flow control, and temperature control to successfully meet their design objectives and attain commercial success. Meeting the continually escalating demand for electricity and ``cheap`` process that will remain a challenge. Environmental protection can depend not only on using energy more efficiently, but on changing the energy conversion process to reduce initial pollutant formation. Further advances in electronics, materials processing, and manufacturing will depend in part on more precise energy management and temperature control. The scale of thermal engineering is quite broad, extending from the very large to the near-molecular level, and from very high temperatures of thousands of degrees to very low ones approaching absolute zero. This breadth of application is illustrated by a review of three specific areas: application of advanced numerical modeling to large boiler furnaces (approaching 100 m in height) in order to improve environmental performance; application of microscale ({approximately}100 {micro}) heat pipes to cool high-performance electronic circuits; and a look at some of the manufacturing processes where heat transfer and thermal analysis improve quality, performance and cost.

  16. Experimental Creep Life Assessment for the Advanced Stirling Convertor Heater Head

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    The United States Department of Energy is planning to develop the Advanced Stirling Radioisotope Generator (ASRG) for the National Aeronautics and Space Administration (NASA) for potential use on future space missions. The ASRG provides substantial efficiency and specific power improvements over radioisotope power systems of heritage designs. The ASRG would use General Purpose Heat Source modules as energy sources and the free-piston Advanced Stirling Convertor (ASC) to convert heat into electrical energy. Lockheed Martin Corporation of Valley Forge, Pennsylvania, is integrating the ASRG systems, and Sunpower, Inc., of Athens, Ohio, is designing and building the ASC. NASA Glenn Research Center of Cleveland, Ohio, manages the Sunpower contract and provides technology development in several areas for the ASC. One area is reliability assessment for the ASC heater head, a critical pressure vessel within which heat is converted into mechanical oscillation of a displacer piston. For high system efficiency, the ASC heater head operates at very high temperature (850 C) and therefore is fabricated from an advanced heat-resistant nickel-based superalloy Microcast MarM-247. Since use of MarM-247 in a thin-walled pressure vessel is atypical, much effort is required to assure that the system will operate reliably for its design life of 17 years. One life-limiting structural response for this application is creep; creep deformation is the accumulation of time-dependent inelastic strain under sustained loading over time. If allowed to progress, the deformation eventually results in creep rupture. Since creep material properties are not available in the open literature, a detailed creep life assessment of the ASC heater head effort is underway. This paper presents an overview of that creep life assessment approach, including the reliability-based creep criteria developed from coupon testing, and the associated heater head deterministic and probabilistic analyses. The approach also

  17. Jet impingement heat transfer enhancement for the GPU-3 Stirling engine

    NASA Technical Reports Server (NTRS)

    Johnson, D. C.; Congdon, C. W.; Begg, L. L.; Britt, E. J.; Thieme, L. G.

    1981-01-01

    A computer model of the combustion-gas-side heat transfer was developed to predict the effects of a jet impingement system and the possible range of improvements available. Using low temperature (315 C (600 F)) pretest data in an updated model, a high temperature silicon carbide jet impingement heat transfer system was designed and fabricated. The system model predicted that at the theoretical maximum limit, jet impingement enhanced heat transfer can: (1) reduce the flame temperature by 275 C (500 F); (2) reduce the exhaust temperature by 110 C (200 F); and (3) increase the overall heat into the working fluid by 10%, all for an increase in required pumping power of less than 0.5% of the engine power output. Initial tests on the GPU-3 Stirling engine at NASA-Lewis demonstrated that the jet impingement system increased the engine output power and efficiency by 5% - 8% with no measurable increase in pumping power. The overall heat transfer coefficient was increased by 65% for the maximum power point of the tests.

  18. Preliminary results from a four-working space, double-acting piston, Stirling engine controls model

    NASA Technical Reports Server (NTRS)

    Daniele, C. J.; Lorenzo, C. F.

    1980-01-01

    A four working space, double acting piston, Stirling engine simulation is being developed for controls studies. The development method is to construct two simulations, one for detailed fluid behavior, and a second model with simple fluid behaviour but containing the four working space aspects and engine inertias, validate these models separately, then upgrade the four working space model by incorporating the detailed fluid behaviour model for all four working spaces. The single working space (SWS) model contains the detailed fluid dynamics. It has seven control volumes in which continuity, energy, and pressure loss effects are simulated. Comparison of the SWS model with experimental data shows reasonable agreement in net power versus speed characteristics for various mean pressure levels in the working space. The four working space (FWS) model was built to observe the behaviour of the whole engine. The drive dynamics and vehicle inertia effects are simulated. To reduce calculation time, only three volumes are used in each working space and the gas temperature are fixed (no energy equation). Comparison of the FWS model predicted power with experimental data shows reasonable agreement. Since all four working spaces are simulated, the unique capabilities of the model are exercised to look at working fluid supply transients, short circuit transients, and piston ring leakage effects.

  19. Experimental study of the influence of different resonators on thermoacoustic conversion performance of a thermoacoustic-Stirling heat engine.

    PubMed

    Luo, E C; Ling, H; Dai, W; Yu, G Y

    2006-12-22

    In this paper, an experimental study of the effect of the resonator shape on the performance of a traveling-wave thermoacoustic engine is presented. Two different resonators were tested in the thermoacoustic-Stirling heat. One resonator is an iso-diameter one, and the other is a tapered one. To have a reasonable comparison reference, we keep the same traveling-wave loop, the same resonant frequency and the same operating pressure. The experiment showed that the resonator shape has significant influence on the global performance of the thermoacoustic-Stirling heat engine. The tapered resonator gives much better performance than the iso-diameter resonator. The tapered resonator system achieved a maximum pressure ratio of about 1.3, a maximum net acoustical power output of about 450 W and a highest thermoacoustic efficiency of about 25%.

  20. Heat transfer from combustion gases to a single row of closely spaced tubes in a swirl crossflow Stirling engine heater

    NASA Technical Reports Server (NTRS)

    Bankston, C. P.; Back, L. H.

    1982-01-01

    This paper describes an experimental program to determine the heat-transfer characteristics of a combustor and heat-exchanger system in a hybrid solar receiver which utilizes a Stirling engine. The system consists of a swirl combustor with a crossflow heat exchanger composed of a single row of 48 closely spaced curved tubes. In the present study, heat-transfer characteristics of the combustor/heat-exchanger system without a Stirling engine have been studied over a range of operating conditions and output levels using water as the working fluid. Nondimensional heat-transfer coefficients based on total heat transfer have been obtained and are compared with available literature data. The results show significantly enhanced heat transfer for the present geometry and test conditions. Also, heat transfer along the length of the tubes is found to vary, the effect depending upon test condition.

  1. Experimental Study of Non-Resonant Self Circulating Heat Transfer Loop Used in Thermoacoustic-Stirling Engines

    NASA Astrophysics Data System (ADS)

    Gao, B.; Luo, E. C.; Dai, W.; Chen, Y. Y.; Hu, J. Y.

    2010-04-01

    A novel heat transfer loop for thermoacoustic-Stirling engines which could substitute for a traditional heat exchanger was developed. This new heat transfer loop uses a pair of check valves to transform oscillating flow into steady flow that allows the oscillating flow system's own working gas to go through a physically remote high-temperature or cold-temperature heat source. Since the early principle experiment has achieved success, this paper explores the real operating performance of this heat transfer loop by coupling with thermoacoustic-Stirling engine. Furthermore, a new type water-cooled heat exchanger was developed in this paper to deduce the extra acoustic power dissipation. In addition, the influence of two kinds of check valves the heat transfer loop was discussed in this paper. The loop with 0.1 mm valve disc thickness shows that the heat transfer capacity is higher than the traditional heat exchanger. Our experiments have demonstrated its feasibility and flexibility for practical applications.

  2. 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.

  3. 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.

  4. A Dielectric Multilayer Filter for Combining Photovoltaics with a Stirling Engine for Improvement of the Efficiency of Solar Electricity Generation

    NASA Astrophysics Data System (ADS)

    Shou, Chun-Hui; Luo, Zhong-Yang; Wang, Tao; Shen, Wei-Dong; Rosengarten, Gary; Wang, Cheng; Ni, Ming-Jiang; Cen, Ke-Fa

    2011-12-01

    In this Letter we outline a dielectric multilayer spectrally selective filter designed for solar energy applications. The optical performance of this 78-layer interference filter constructed by TiOx and SiO2 is presented. A hybrid system combining photovoltaic cells with a solar-powered Stirling engine using the designed filter is analyzed. The calculated results show the advantages of this spectrally selective method for solar power generation.

  5. Evaluation of Requirements for Militarization of 3-kW Free-Piston Stirling Engine Generator Set

    DTIC Science & Technology

    1982-01-01

    AD _ o EVALUATION OF REQUIREMENTS FOR •i MILITARIZATION OF 3-kW FREE-PISTON STIRLING ENGINE GENERATOR SET S Thomas J. Marusak Mechanical Technology ...PROGRAM ELEMENT. PROJECT, TASK Mechanical Technology Inc. AREA & WORK UNIT NUMSERS 968 Albany-Shaker Road Latham, NY 12110 11. CONTROLLING OFFICE NAME AND...Mechanical Technology Incorporated (MTI) is developing the FPSE for stationary com- mercial applications in the size range below 10 kW. Because of the poten

  6. Structural Benchmark Creep Testing for the Advanced Stirling Convertor Heater Head

    NASA Technical Reports Server (NTRS)

    Krause, David L.; Kalluri, Sreeramesh; Bowman, Randy R.; Shah, Ashwin R.

    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 use on long duration Science missions such as lunar applications, Mars rovers, and deep space missions. For the inherent long life times required, a structurally significant design limit for the heater head component of the ASRG Advanced Stirling Convertor (ASC) is creep deformation induced at low stress levels and high temperatures. Demonstrating proof of adequate margins on creep deformation and rupture for the operating conditions and the MarM-247 material of construction is a challenge that the NASA Glenn Research Center is addressing. The combined analytical and experimental program ensures integrity and high reliability of the heater head for its 17-year design life. The life assessment approach starts with an extensive series of uniaxial creep tests on thin MarM-247 specimens that comprise the same chemistry, microstructure, and heat treatment processing as the heater head itself. This effort addresses a scarcity of openly available creep properties for the material as well as for the virtual absence of understanding of the effect on creep properties due to very thin walls, fine grains, low stress levels, and high-temperature fabrication steps. The approach continues with a considerable analytical effort, both deterministically to evaluate the median creep life using nonlinear finite element analysis, and probabilistically to calculate the heater head s reliability to a higher degree. Finally, the approach includes a substantial structural benchmark creep testing activity to calibrate and validate the analytical work. This last element provides high fidelity testing of prototypical heater head test articles; the testing includes the relevant material issues and the essential multiaxial stress state, and applies prototypical and accelerated temperature profiles for timely results in a

  7. 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.

  8. Performance assessment and optimization of an irreversible nano-scale Stirling engine cycle operating with Maxwell-Boltzmann gas

    NASA Astrophysics Data System (ADS)

    Ahmadi, Mohammad H.; Ahmadi, Mohammad-Ali; Pourfayaz, Fathollah

    2015-09-01

    Developing new technologies like nano-technology improves the performance of the energy industries. Consequently, emerging new groups of thermal cycles in nano-scale can revolutionize the energy systems' future. This paper presents a thermo-dynamical study of a nano-scale irreversible Stirling engine cycle with the aim of optimizing the performance of the Stirling engine cycle. In the Stirling engine cycle the working fluid is an Ideal Maxwell-Boltzmann gas. Moreover, two different strategies are proposed for a multi-objective optimization issue, and the outcomes of each strategy are evaluated separately. The first strategy is proposed to maximize the ecological coefficient of performance (ECOP), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F . Furthermore, the second strategy is suggested to maximize the thermal efficiency ( η), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F). All the strategies in the present work are executed via a multi-objective evolutionary algorithms based on NSGA∥ method. Finally, to achieve the final answer in each strategy, three well-known decision makers are executed. Lastly, deviations of the outcomes gained in each strategy and each decision maker are evaluated separately.

  9. Development of a residential free-piston Stirling engine heat pump

    NASA Astrophysics Data System (ADS)

    Ackermann, Robert A.

    After several years of development, the free-piston Stirling engine heat pump (FPSE/HP) has successfully met proof-of-concept targets. The performance targets were achieved during an off-site test and evaluation program conducted at the Lennox Industries Engineering Center. The performance achieved for the module was a cooling thermal coefficient of performance (COP) of 0.91 and a heating thermal COP of 1.62. In addition to its performance achievement, the FPSE/HP module demonstrated good reliability in over 60 days of operation and ran stably and repeatably over a range of ambient conditions from 0 to 105 F. This paper will provide a description of the FPSE/HP module tested at Lennox, describe the developmental history of the FPSE/HP at Mechanical Technology Incorporated (MTI), and present the results of the Lennox tests. This work has been a collaborative effort of MTI, Oak Ridge National Laboratory (ORNL), the Department of Energy (DOE), and the Gas Research Institute (GRI). The financial and technical support provided by ORNL, DOE, and GRI was responsible for the success achieved.

  10. Development and Integration of an Advanced Stirling Convertor Linear Alternator Model for a Tool Simulating Convertor Performance and Creating Phasor Diagrams

    NASA Technical Reports Server (NTRS)

    Metscher, Jonathan F.; Lewandowski, Edward J.

    2013-01-01

    A simple model of the Advanced Stirling Convertors (ASC) linear alternator and an AC bus controller has been developed and combined with a previously developed thermodynamic model of the convertor for a more complete simulation and analysis of the system performance. The model was developed using Sage, a 1-D thermodynamic modeling program that now includes electro-magnetic components. The convertor, consisting of a free-piston Stirling engine combined with a linear alternator, has sufficiently sinusoidal steady-state behavior to allow for phasor analysis of the forces and voltages acting in the system. A MATLAB graphical user interface (GUI) has been developed to interface with the Sage software for simplified use of the ASC model, calculation of forces, and automated creation of phasor diagrams. The GUI allows the user to vary convertor parameters while fixing different input or output parameters and observe the effect on the phasor diagrams or system performance. The new ASC model and GUI help create a better understanding of the relationship between the electrical component voltages and mechanical forces. This allows better insight into the overall convertor dynamics and performance.

  11. Advanced expander test bed engine

    NASA Technical Reports Server (NTRS)

    Mitchell, J. P.

    1992-01-01

    The Advanced Expander Test Bed (AETB) is a key element in NASA's Space Chemical Engine Technology Program for development and demonstration of expander cycle oxygen/hydrogen engine and advanced component technologies applicable to space engines as well as launch vehicle upper stage engines. The AETB will be used to validate the high pressure expander cycle concept, study system interactions, and conduct studies of advanced mission focused components and new health monitoring techniques in an engine system environment. The split expander cycle AETB will operate at combustion chamber pressures up to 1200 psia with propellant flow rates equivalent to 20,000 lbf vacuum thrust.

  12. Lower-end dynamic characteristics of a magnetically coupled free-piston Stirling engine/compressor system

    NASA Astrophysics Data System (ADS)

    Chen, G.; McEntee, J.

    In a prototype, the engine power piston is connected to the compressor piston through a magnetic coupling; a linear starter is used to start the system and a variable-stiffness gas spring is used to resonate the system lower-end over the operating frequency range of the system. System characteristics of the lower end coupled through the coupling to the engine, and considerations of the engine response, are investigated analytically with a simplified model. The system analysis is also used to obtain an understanding of the free-piston Stirling engine/magnetic coupling/compressor assembly dynamic behavior for variations in engine power and lower-end resonance. In order for the machine to operate without excessively large forces transmitted through the magnetic coupling, the analysis indicates that both the engine and the compressor section should be independently resonant to keep the engine and the lower-end oscillating amplitude identical.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Thermodynamic analysis of onset characteristics in a miniature thermoacoustic Stirling engine

    NASA Astrophysics Data System (ADS)

    Huang, Xin; Zhou, Gang; Li, Qing

    2013-06-01

    This paper analyzes the onset characteristics of a miniature thermoacoustic Stirling heat engine using the thermodynamic analysis method. The governing equations of components are reduced from the basic thermodynamic relations and the linear thermoacoustic theory. By solving the governing equation group numerically, the oscillation frequencies and onset temperatures are obtained. The dependences of the kinds of working gas, the length of resonator tube, the diameter of resonator tube, on the oscillation frequency are calculated. Meanwhile, the influences of hydraulic radius and mean pressure on the onset temperature for different working gas are also presented. The calculation results indicate that there exists an optimal dimensionless hydraulic radius to obtain the lowest onset temperature, whose value lies in the range of 0.30-0.35 for different working gases. Furthermore, the amplitude and phase relationship of pressures and volume flows are analyzed in the time-domain. Some experiments have been performed to validate the calculations. The calculation results agree well with the experimental values. Finally, an error analysis is made, giving the reasons that cause the errors of theoretical calculations.

  19. Evaluation of candidate Stirling engine heater tube alloys for 1000 hours at 760 C

    NASA Technical Reports Server (NTRS)

    Misencik, J. A.

    1980-01-01

    Six tubing alloys were endurance tested in a diesel fired, Stirling engine simulator materials test rig for 1000 hours of 760 C while pressurized at 17 to 21 MPa with either hydrogen or helium. The alloys tested were N 155, A 286, Incoloy 800, 19 9DL, Nitronic 40 and 316 stainless steel. The alloys were in the form of thin wall tubing. Hydrogen permeated rapidly through the tube walls of all six alloys when they were heated to 760 C. Helium was readily contained. Creep rupture failures occurred in four of the six alloys pressurized with hydrogen. Only two alloys survived the 1000 hour endurance test with no failures. Simultaneous exposure to either hydrogen or helium and the combustion environment did not seriously degrade the tensile strength of the six alloys in room temperature or 760 C tests after exposure. Decreases in room temperature ductility were observed and are attributed to aging rather than to hydrogen embrittlement in three of the alloys. However, there may be a hydrogen embrittlement effect in the N 155, 19 9DL, and Nitronic 40 alloys.

  20. Oxidation and corrosion resistance of candidate Stirling engine heater-head-tube alloys

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Barrett, C. A.

    1984-01-01

    Sixteen candidate iron base Stirling engine heater head tube alloys are evaluated in a diesel fuel fired simulator materials test rig to determine their oxidation and corrosion resistance. Sheet specimens are tested at 820 C for 3500 hr in 5 hr heating cycles. Specific weight change data and an attack parameter are used to categorize the alloys into four groups; 10 alloys show excellent for good oxidation and corrosion resistance and six alloys exhibit poor or catastrophic resistance. Metallographic, X-ray, and electron microprobe analyses aid in further characterizing the oxidation and corrosion behavior of the alloys. Alloy compositions, expecially the reactive elements aluminum, titanium, and chromium, play a major role in the excellent oxidation and corrosion behavior of the alloys. The best oxidation resistance is associated with the formation of an iron nickel aluminum outer oxide scale, an intermediate oxide scale rich in chromium and titanium, and an aluminum outer oxide scale adjacent to the metallic substrate, which exhibits a zone of internal oxidation of aluminum and to some extent titanium.

  1. 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.

  2. Experimental study on a co-axial pulse tube cryocooler driven by a small thermoacoustic stirling engine

    NASA Astrophysics Data System (ADS)

    Chen, M.; Ju, L. Y.; Hao, H. X.

    2014-01-01

    Small scale thermoacoustic heat engines have advantages in fields like space exploration and domestic applications considering small space occupation and ease of transport. In the present paper, the influence of resonator diameter on the general performance of a small thermoacoustic Stirling engine was experimentally investigated using helium as the working gas. Reducing the diameter of the resonator appropriately is beneficial for lower onset heating temperature, lower frequency and higher pressure amplitude. Based on the pressure distribution in the small thermoacoustic engine, an outlet for the acoustic work transmission was made to combine the engine and a miniature co-axial pulse tube cooler. The cooling performance of the whole refrigeration system without any moving part was tested. Experimental results showed that further efforts are required to optimize the engine performance and its match with the co-axial pulse tube cooler in order to obtain better cooling performance, compared with its original operating condition, driven by a traditional electrical linear compressor.

  3. High Temperature Solid Lubricant Materials for Heavy Duty and Advanced Heat Engines

    NASA Technical Reports Server (NTRS)

    Dellacorte, C.; Wood, J. C.

    1994-01-01

    Advanced engine designs incorporate higher mechanical and thermal loading to achieve efficiency improvements. This approach often leads to higher operating temperatures of critical sliding elements (e.g. piston ring/cylinder wall contacts and valve guides) which compromise the use of conventional and even advanced synthetic liquid lubricants. For these applications solid lubricants must be considered. Several novel solid lubricant composites and coatings designated PS/PM200 have been employed to dry and marginally oil lubricated contacts in advanced heat engines. These applications include cylinder kits of heavy duty diesels, and high temperature Stirling engines, sidewall seals of rotary engines, and various exhaust valve and exhaust component applications. This paper describes the tribological and thermophysical properties of these tribomaterials and reviews the results of applying them to engine applications. Other potential tribological materials and applications are also discussed with particular emphasis on heavy duty and advanced heat engines.

  4. Advanced Natural Gas Reciprocating Engine(s)

    SciTech Connect

    Pike, Edward

    2014-03-31

    The objective of the Cummins ARES program, in partnership with the US Department of Energy (DOE), is to develop advanced natural gas engine technologies that increase engine system efficiency at lower emissions levels while attaining lower cost of ownership. The goals of the project are to demonstrate engine system achieving 50% Brake Thermal Efficiency (BTE) in three phases, 44%, 47% and 50% (starting baseline efficiency at 36% BTE) and 0.1 g/bhp-hr NOx system out emissions (starting baseline NOx emissions at 2 – 4 g/bhp-hr NOx). Primary path towards above goals include high Brake Mean Effective Pressure (BMEP), improved closed cycle efficiency, increased air handling efficiency and optimized engine subsystems. Cummins has successfully demonstrated each of the phases of this program. All targets have been achieved through application of a combined set of advanced base engine technologies and Waste Heat Recovery from Charge Air and Exhaust streams, optimized and validated on the demonstration engine and other large engines. The following architectures were selected for each Phase: Phase 1: Lean Burn Spark Ignited (SI) Key Technologies: High Efficiency Turbocharging, Higher Efficiency Combustion System. In production on the 60/91L engines. Over 500MW of ARES Phase 1 technology has been sold. Phase 2: Lean Burn Technology with Exhaust Waste Heat Recovery (WHR) System Key Technologies: Advanced Ignition System, Combustion Improvement, Integrated Waste Heat Recovery System. Base engine technologies intended for production within 2 to 3 years Phase 3: Lean Burn Technology with Exhaust and Charge Air Waste Heat Recovery System Key Technologies: Lower Friction, New Cylinder Head Designs, Improved Integrated Waste Heat Recovery System. Intended for production within 5 to 6 years Cummins is committed to the launch of next generation of large advanced NG engines based on ARES technology to be commercialized worldwide.

  5. Advanced engine technology

    SciTech Connect

    Heisler, H.

    1995-12-31

    This book provides a comprehensive reference for anyone wanting to study the way in which modern vehicle engines work, and why they are designed as they are. The book covers virtually all configurations of commercially-produced engines, and features the latest engine technology including up-to-date coverage of electronic engine management and exhaust emission control. Chapters cover valves and camshafts; camshaft chain belt and gear train drives; engine balance and vibration; combustion chamber design and engine performance; induction and exhaust systems; supercharging systems; carburetted fuel systems; fuel injection systems; ignition systems; engine testing equipment; diesel in-line fuel injection pump systems; diesel rotary and unit injector fuel injection pump systems; emission control; cooling and lubrication systems; and alternative power units.

  6. Summary of Stirling Convertor Testing at GRC

    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 watt electric power output range. Tests at GRC have accumulated over 80,000 hours of operation. Test articles have been received from Infinia Corporation of Kennewick, WA and from Sunpower of Athens, OH. 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 longterm 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.

  7. 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

  8. 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.

  9. Design and development of Stirling engines for stationary-power-generation applications in the 500- to 3000-horsepower range. Phase I final report

    SciTech Connect

    1980-10-01

    A program plan and schedule for the implementation of the proposed conceptual designs through the remaining four phases of the overall large Stirling engine development program was prepared. The objective of Phase II is to prepare more detailed designs of the conceptual designs prepared in Phase I. At the conclusion of Phase II, a state-of-the-art design will be selected from the candidate designs developed in Phase I for development. The objective of Phase III is to prepare manufacturing drawings of the candidate engine design. Also, detailed manufacturing drawings of both 373 kW (500 hp) and 746 kW (1000 hp) power pack skid systems will be completed. The power pack skid systems will include the generator, supporting skid, controls, and other supporting auxiliary subsystems. The Stirling cycle engine system (combustion system, Stirling engine, and heat transport system) will be mounted in the power pack skid system. The objective of Phase IV is to procure parts for prototype engines and two power pack skid systems and to assemble Engines No. 1 and 2. The objective of Phase V is to perform extensive laboratory and demonstration testing of the Stirling engines and power pack skid systems, to determine the system performance and cost and commercialization strategy. Scheduled over a 6 yr period the cost of phases II through V is estimated at $22,063,000. (LCL)

  10. Energy-state formulation of lumped volume dynamic equations with application to a simplified free piston Stirling engine

    NASA Technical Reports Server (NTRS)

    Daniele, C. J.; Lorenzo, C. F.

    1979-01-01

    Lumped volume dynamic equations are derived using an energy state formulation. This technique requires that kinetic and potential energy state functions be written for the physical system being investigated. To account for losses in the system, a Rayleigh dissipation function is formed. Using these functions, a Lagrangian is formed and using Lagrange's equation, the equations of motion for the system are derived. The results of the application of this technique to a lumped volume are used to derive a model for the free piston Stirling engine. The model was simplified and programmed on an analog computer. Results are given comparing the model response with experimental data.

  11. A review of test results on solar thermal power modules with dish-mounted Stirling and Brayton cycle engines

    NASA Technical Reports Server (NTRS)

    Jaffe, Leonard D.

    1988-01-01

    This paper presents results of development tests of various solar thermal parabolic dish modules and assemblies that used dish-mounted Brayton or Stirling cycle engines for production of electric power. These tests indicate that early modules achieve net efficiencies up to 29 percent in converting sunlight to electricity, as delivered to the grid. Various equipment deficiencies were observed and a number of malfunctions occurred. The performance measurements, as well as the malfunctions and other test experience, provided information that should be of value in developing systems with improved performance and reduced maintenance.

  12. Energy-state formulation of lumped volume dynamic equations with application to a simplified free piston Stirling engine

    NASA Technical Reports Server (NTRS)

    Daniele, C. J.; Lorenzo, C. F.

    1979-01-01

    Lumped volume dynamic equations are derived using an energy-state formulation. This technique requires that kinetic and potential energy state functions be written for the physical system being investigated. To account for losses in the system, a Rayleigh dissipation function is also formed. Using these functions, a Lagrangian is formed and using Lagrange's equation, the equations of motion for the system are derived. The results of the application of this technique to a lumped volume are used to derive a model for the free-piston Stirling engine. The model was simplified and programmed on an analog computer. Results are given comparing the model response with experimental data.

  13. Performance mapping of the STM4-120 kinematic Stirling engine using a statistical design of experiments method

    NASA Astrophysics Data System (ADS)

    Powell, M. A.; Rawlinson, K. S.

    A kinetic Stirling cycle engine, the Stirling Thermal Motors (STM) STM4-120, was tested at the Sandia National Laboratories Engine Test Facility (ETF) from March 1989-August 1992. Sandia is interested in determining this engine's potential for solar-thermal-electric applications. The last round of testing was conducted from July-August 1992 using Sandia-designed gas-fired heat pipe evaporators as the heat input system to the engine. The STM4-120 was performance mapped over a range of sodium vapor temperatures, cooling water temperatures, and cycle pressures. The resulting shaft power output levels ranged from 5-9 kW. The engine demonstrated high conversion efficiency (24-31%) even though the power output level was less than 40% of the rated output of 25 kW. The engine had been previously derated from 25 kW to 10 kW shaft power due to mechanical limitations that were identified by STM during parallel testing at their facility in Ann Arbor, MI. A statistical method was used to design the experiment, to choose the experimental points, and to generate correlation equations describing the engine performance given the operating parameters. The testing was truncated due to a failure of the heat pipe system caused by entrainment of liquid sodium in the condenser section of the heat pipes. Enough data was gathered to generate the correlations and to demonstrate the experimental technique. The correlation is accurate in the experimental space and is simple enough for use in hand calculations and spreadsheet-based system models. Use of this method can simplify the construction of accurate performance and economic models of systems in which the engine is a component. The purpose of this paper is to present the method used to design the experiments and to analyze the performance data.

  14. 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.

  15. Assessment of 25 kW free-piston Stirling technology alternatives for solar applications

    NASA Technical Reports Server (NTRS)

    Erbeznik, Raymond M.; White, Maurice A.; Penswick, L. B.; Neely, Ronald E.; Ritter, Darren C.; Wallace, David A.

    1992-01-01

    The final design, construction, and testing of a 25-kW free-piston advanced Stirling conversion system (ASCS) are examined. The final design of the free-piston hydraulic ASCS consists of five subsystems: heat transport subsystem (solar receiver and pool boiler), free-piston hydraulic Stirling engine, hydraulic subsystem, cooling subsystem, and electrical and control subsystem. Advantages and disadvantages are identified for each technology alternative. Technology alternatives considered are gas bearings vs flexure bearings, stationary magnet linear alternator vs moving magnetic linear alternator, and seven different control options. Component designs are generated using available in-house procedures to meet the requirements of the free-piston Stirling convertor configurations.

  16. Assessment of 25 kW free-piston Stirling technology alternatives for solar applications

    NASA Astrophysics Data System (ADS)

    Erbeznik, Raymond M.; White, Maurice A.; Penswick, L. B.; Neely, Ronald E.; Ritter, Darren C.; Wallace, David A.

    The final design, construction, and testing of a 25-kW free-piston advanced Stirling conversion system (ASCS) are examined. The final design of the free-piston hydraulic ASCS consists of five subsystems: heat transport subsystem (solar receiver and pool boiler), free-piston hydraulic Stirling engine, hydraulic subsystem, cooling subsystem, and electrical and control subsystem. Advantages and disadvantages are identified for each technology alternative. Technology alternatives considered are gas bearings vs flexure bearings, stationary magnet linear alternator vs moving magnetic linear alternator, and seven different control options. Component designs are generated using available in-house procedures to meet the requirements of the free-piston Stirling convertor configurations.

  17. Advances in yeast genome engineering.

    PubMed

    David, Florian; Siewers, Verena

    2015-02-01

    Genome engineering based on homologous recombination has been applied to yeast for many years. However, the growing importance of yeast as a cell factory in metabolic engineering and chassis in synthetic biology demands methods for fast and efficient introduction of multiple targeted changes such as gene knockouts and introduction of multistep metabolic pathways. In this review, we summarize recent improvements of existing genome engineering methods, the development of novel techniques, for example for advanced genome redesign and evolution, and the importance of endonucleases as genome engineering tools.

  18. 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

  19. 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

  20. 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.