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Sample records for 50-kwe reference stirling

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Stirling engines

    SciTech Connect

    Walker, G.

    1980-01-01

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

  8. Stirling engine design manual. Second edition

    SciTech Connect

    Martini, W.R.

    1983-01-01

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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Stirling engine application study

    SciTech Connect

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

    1983-03-01

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

  18. 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.

  19. 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…

  20. 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.

  1. 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.

  2. 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.

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

    NASA Technical Reports Server (NTRS)

    Sliney, H. 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 experimental 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.

  4. 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.

  5. Liquid piston Stirling engines

    SciTech Connect

    West, C.D.

    1983-01-01

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

  6. 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.

  7. The optimization of Stirling refrigerator and Stirling heat engine

    NASA Astrophysics Data System (ADS)

    Zhu, Xin-Mei

    2007-03-01

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

  8. 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

  9. 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

  10. 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.

  11. Small Stirling Cycle Convertors

    NASA Astrophysics Data System (ADS)

    Penswick, L. Barry; Schreiber, Jeffery

    2005-02-01

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

  12. Stirling technology development status

    NASA Astrophysics Data System (ADS)

    Dochat, George R.; Dudenhoefer, James E.

    1993-01-01

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

  13. Stirling technology development status

    SciTech Connect

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

    1993-01-15

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

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. A Stirling Idea

    NASA Technical Reports Server (NTRS)

    1998-01-01

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

  19. Stirling in Another Context.

    ERIC Educational Resources Information Center

    Papademetriou, Peter

    1981-01-01

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

  20. Stirling cycle piston engine

    SciTech Connect

    Morgan, G. R.

    1985-02-12

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

  1. The Stirling engine

    NASA Astrophysics Data System (ADS)

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

  2. Stirling machine operating experience

    SciTech Connect

    Ross, B.; Dudenhoefer, J.E.

    1994-09-01

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

  3. 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.

  4. 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.

  5. NASA GRC Stirling Power Overview

    NASA Technical Reports Server (NTRS)

    Cornell, Peggy A.

    2014-01-01

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

  6. Performance of Stirling Engines

    NASA Astrophysics Data System (ADS)

    Iwamoto, Shoichi; Hirata, Koichi; Toda, Fujio

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

  7. Stirling cycle cryogenic cooler

    NASA Astrophysics Data System (ADS)

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

    1983-06-01

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

  8. Stirling cycle cryogenic cooler

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  9. 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.

  10. 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.

  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. 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.

  13. 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.

  14. Free-piston Stirling coolers for intermediate lift temperatures

    NASA Astrophysics Data System (ADS)

    Berchowitz, David M.

    Irreversibilities in Stirling cycle coolers are discussed with reference to designing machines for operation at warmer temperatures rather than cryogenic applications. It is shown that the sensitivity of the cycle to some losses is dependent on the temperature ratio. The free-piston configuration employs a linear motor which greatly reduces side loads and facilitates the implementation of noncontact gas bearings. Mechanism efficiencies are therefore much higher than in crank machines which leads to an overall performance advantage. It is expected that an optimized free-piston Stirling refrigerator cooler could exceed 60 percent of Carnot overall.

  15. Application of the GRC Stirling Convertor System Dynamic Model

    NASA Technical Reports Server (NTRS)

    Regan, Timothy F.; Lewandowski, Edward J.; Schreiber, Jeffrey G. (Technical Monitor)

    2004-01-01

    The GRC Stirling Convertor System Dynamic Model (SDM) has been developed to simulate dynamic performance of power systems incorporating free-piston Stirling convertors. This paper discusses its use in evaluating system dynamics and other systems concerns. Detailed examples are provided showing the use of the model in evaluation of off-nominal operating conditions. The many degrees of freedom in both the mechanical and electrical domains inherent in the Stirling convertor and the nonlinear dynamics make simulation an attractive analysis tool in conjunction with classical analysis. Application of SDM in studying the relationship of the size of the resonant circuit quality factor (commonly referred to as Q) in the various resonant mechanical and electrical sub-systems is discussed.

  16. A pistonless Stirling cooler

    NASA Astrophysics Data System (ADS)

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

    2002-01-01

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

  17. Stirling cycle machine

    SciTech Connect

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

    1990-06-05

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

  18. Some considerations of the design of displacers for Ringbom Stirling engines

    SciTech Connect

    Fauvel, O.R.; Kentfield, J.A.C.; Walker, G.

    1984-08-01

    The Ringbom Stirling engine is a hybrid of the kinematic Stirling engine having shaft output power and variable speed and of the free piston engine in which the components are driven by changes in working space pressure. Experiments with Ringbom Stirling engines have led to the suspicion that the 'weak link' of the engine is the free displacer. This paper examines some of the factors which must be addressed in the design of displacers for these engines with reference to the thermal, pressure, and dynamical considerations.

  19. 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.

  20. MEMS Stirling Cooler Development Update

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.; Wesolek, Danielle

    2003-01-01

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

  1. 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.

  2. 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.

  3. Development of Electronic Load Controllers for Free-Piston Stirling Convertors Aided by Stirling Simulation Model

    NASA Technical Reports Server (NTRS)

    Regan, Timothy F.

    2004-01-01

    The free-piston Stirling convertor end-to-end modeling effort at the NASA Glenn Research Center has produced a software-based test bed in which free-piston Stirling convertors can be simulated and evaluated. The simulation model includes all the components of the convertor: the Stirling cycle engine, heat source, linear alternator, controller, and load. So far, it has been used in evaluating the performance of electronic controller designs. Three different controller design concepts were simulated using the model: 1) Controllers with parasitic direct current loading. 2) Controllers with parasitic alternating current loading. 3) Controllers that maintain a reference current. The free-piston Stirling convertor is an electromechanical device that operates at resonance. It is the function of the electronic load controller to ensure that the electrical load seen by the machine is always great enough to keep the amplitude of the piston and alternator oscillation at the rated value. This is done by regulating the load on the output bus. The controller monitors the instantaneous voltage, regulating it by switching loads called parasitic loads onto the bus whenever the bus voltage is too high and removing them whenever the voltage is too low. In the first type of controller, the monitor-ing and switching are done on the direct-current (dc) bus. In the second type, the alternating current bus is used. The model allows designers to test a controller concept before investing time in hardware. The simulation code used to develop the model also offers detailed models of digital and analog electronic components so that the resulting designs are realistic enough to translate directly into hardware circuits.

  4. Stirling material technology

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

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

    SciTech Connect

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

    1997-12-31

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

  6. 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.

  7. Innovation at Stirling

    NASA Astrophysics Data System (ADS)

    1998-11-01

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

  8. Dish Stirling solar receiver program

    NASA Technical Reports Server (NTRS)

    Haglund, R. A.

    1980-01-01

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

  9. Novel diaphragm based Stirling cryocooler

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  10. High performance solar Stirling system

    NASA Technical Reports Server (NTRS)

    Stearns, J. W.; Haglund, R.

    1981-01-01

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

  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

    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.

  12. Stirling Microregenerators Fabricated and Tested

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.

    2004-01-01

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

  13. Automotive Stirling Engine Development Program. RESD Summary report

    SciTech Connect

    Not Available

    1984-05-01

    This is the final report compiling a summary of the information presented and discussed at the May 1983 Automotive Stirling Engine (AES) Reference Engine System Design (RESD) review held at the NASA Lewis Research Center. The design of the engine and its 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.

  14. Miniaturized stirling type cooler

    SciTech Connect

    Pundak, N.

    1988-09-13

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

  15. Stirling engines and irrigation pumping

    SciTech Connect

    West, C.D.

    1987-08-01

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

  16. Free-Piston Stirling Engines

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.

    1989-01-01

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

  17. 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.

  18. Stirling engine with pressurized crankcase

    SciTech Connect

    Corey, John A.

    1988-01-01

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

  19. Extended Operation of Stirling Convertors

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  20. A recuperative superfluid stirling refrigerator

    SciTech Connect

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

    1993-07-01

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

  1. Extended Operation of Stirling Convertors

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  2. Stirling engines and irrigation pumping

    SciTech Connect

    West, C.D.

    1988-01-01

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

  3. Innovation at Stirling

    NASA Astrophysics Data System (ADS)

    1998-11-01

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

  4. The cavity heat pipe Stirling receiver for space solar dynamics

    NASA Technical Reports Server (NTRS)

    Kesseli, James B.; Lacy, Dovie E.

    1989-01-01

    The receiver/storage unit for the low-earth-orbiting Stirling system is discussed. The design, referred to as the cavity heat pipe (CHP), has been optimized for minimum specific mass and volume width. A specific version of this design at the 7-kWe level has been compared to the space station Brayton solar dynamic design. The space station design utilizes a eutectic mixture of LiF and CaF2. Using the same phase change material, the CHP has been shown to have a specific mass of 40 percent and a volume of 5 percent of that of the space station Brayton at the same power level. Additionally, it complements the free-piston Stirling engine in that it also maintains a relatively flat specific mass down to at least 1 kWe. The technical requirements, tradeoff studies, critical issues, and critical technology experiments are discussed.

  5. Stirling engine with a liquid working substance

    SciTech Connect

    Swift, G.W.

    1989-06-01

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

  6. Overview of a stirling engine test project

    NASA Technical Reports Server (NTRS)

    Slaby, J. G.

    1980-01-01

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

  7. Stirling machines: From potential to practicality

    SciTech Connect

    Ross, B.

    1988-06-01

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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Stability of split Stirling refrigerators

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

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

  13. Stirling and Vuilleumier heat pumps

    SciTech Connect

    Wurm, J.

    1990-01-01

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

  14. Mod II Stirling engine overviews

    NASA Technical Reports Server (NTRS)

    Farrell, Roger A.

    1988-01-01

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

  15. Stirling Convertor Fasteners Reliability Quantification

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  16. 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.

  17. Automotive Stirling Engine Development Program: A success

    SciTech Connect

    Tabata, W.K.

    1987-01-01

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

  18. 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.

  19. 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)

  20. 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.

  1. A novel experimentally validated Stirling cycle simulation

    SciTech Connect

    Rix, D.H.

    1983-08-01

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

  2. 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.

  3. 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.

  4. Solar-Electric Dish Stirling System Development

    SciTech Connect

    Mancini, T.R.

    1997-12-31

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

  5. 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.

  6. 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.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  8. 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.

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

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.

    2003-01-01

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

  10. Solar powered Stirling cycle electrical generator

    NASA Astrophysics Data System (ADS)

    Shaltens, Richard K.

    1991-03-01

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

  11. 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.

  12. Solar powered Stirling cycle electrical generator

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.

    1991-01-01

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

  13. 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

  14. 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.

  15. Liquid-piston Stirling machines

    SciTech Connect

    West, C.D.

    1984-01-01

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

  16. 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).

  17. Rotary Stirling-Cycle Engine And Generator

    NASA Technical Reports Server (NTRS)

    Chandler, Joseph A.

    1990-01-01

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

  18. Advanced Stirling Convertor Testing at GRC

    NASA Technical Reports Server (NTRS)

    Schifer, Nick; Oriti, Salvatore M.

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2004-02-01

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

  20. 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.

  1. 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).

  2. Rebirth of the stirling engine

    SciTech Connect

    Sternlicht, B.

    1983-01-01

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

  3. Advanced Stirling Radioisotope Generator Life Certification Plan

    NASA Technical Reports Server (NTRS)

    Rusick, Jeffrey J.; Zampino, Edward J.

    2013-01-01

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

  4. Simple and Clear Proofs of Stirling's Formula

    ERIC Educational Resources Information Center

    Niizeki, Shozo; Araki, Makoto

    2010-01-01

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

  5. On the Need for Multidimensional Stirling Simulations

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  6. 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.

  7. 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.

  8. 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.

  9. Practical bellows seals for Stirling engines

    SciTech Connect

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

    1987-01-01

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

  10. Review of Computational Stirling Analysis Methods

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  11. Stirling Air Conditioner for Compact Cooling

    SciTech Connect

    2010-09-01

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

  12. Anatomy of the Stirling engine cycle

    NASA Astrophysics Data System (ADS)

    Organ, A. J.

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

  13. Demonstration experiments with a Stirling engine

    NASA Astrophysics Data System (ADS)

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

    1994-05-01

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

  14. 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.

  15. 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.

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

    NASA Technical Reports Server (NTRS)

    Simetkosky, M. A.

    1983-01-01

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

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

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

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

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  19. 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.

  20. 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.

  1. Vibration Testing of Stirling Power Convertors

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    The NASA John H. Glenn Research Center (GRC) and the U.S. Department of Energy (DOE) are currently developing a high efficient, long life, free piston Stirling convertor for use as an advanced spacecraft power system for future NASA missions. As part of this development, a Stirling Technology Demonstrator Convertor (TDC), developed by Stirling Technology Company (STC) for DOE, was vibration tested at GRC s Structural Dynamics Laboratory (SDU7735) in November- December 1999. This testing demonstrated that the Stirling TDC is able to withstand the harsh random vibration (20 to 2000 Hertz) seen during a typical spacecraft launch and survive with no structural damage or functional power performance degradation, thereby enabling its usage in future spacecraft power systems. The Stirling Vibration Test Team at NASA GRC and STC personnel conducted tests on a single 55 electric watt TDC. The purpose was to characterize the TDC s structural response to vibration and determine if the TDC could survive the vibration criteria established by the Jet Propulsion Laboratory (JPL) for launch environments. The TDC was operated at full-stroke and full power conditions during the vibration testing. The TDC was tested in two orientations, with the direction of vibration parallel and perpendicular to the TDC s moving components (displacer and piston). The TDC successfully passed a series of sine and random vibration tests. The most severe test was a 12.3 Grms random vibration test (peak vibration level of 0.2 g2/Hz from 50 to 250 Hertz) with test durations of 3 minutes per axis. The random vibration test levels were chosen to simulate, with margin, the maximum anticipated launch vibration conditions. As a result of this very successful vibration testing and successful evaluations in other key technical readiness areas, the Stirling power system is now considered a viable technology for future application for NASA spacecraft missions. Possible usage of the Stirling power system would be

  2. Numerical analysis of Stirling engine

    NASA Astrophysics Data System (ADS)

    Sekiya, Hiroshi

    1992-11-01

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

  3. 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.

  4. Ferroelectric Stirling-Cycle Refrigerator

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  5. 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.

  6. 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.

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

    SciTech Connect

    Not Available

    1982-08-01

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

  8. 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.

  9. 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.

  10. 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.

  11. Dynamic Capability of an Operating Stirling Convertor

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  12. 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.

  13. Alternative fuel capabilities of the Mod II Stirling vehicle

    SciTech Connect

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

    1988-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1991-01-01

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

  15. 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.

  16. Magnetic bearings for free-piston Stirling engines

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    The feasibility and efficiency 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 efficieny 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.

  17. Magnetic bearings for free-piston Stirling engines

    NASA Astrophysics Data System (ADS)

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

    The feasibility and efficiency 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 efficieny 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.

  18. Magnetic bearings for free-piston Stirling engines

    NASA Astrophysics Data System (ADS)

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

    1992-08-01

    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. A compendium of solar dish/Stirling technology

    SciTech Connect

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

    1994-01-01

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

  20. 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.

  1. A new, versatile Stirling energy conversion unit

    SciTech Connect

    Meijer, R.J.; Ziph, B.

    1982-08-01

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

  2. Hermetic metal seals for Stirling engines

    SciTech Connect

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

    1984-08-01

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

  3. Base engine for solar Stirling power

    SciTech Connect

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

    1984-03-01

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

  4. 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.

  5. Advanced radioisotope heat source for Stirling Engines

    NASA Astrophysics Data System (ADS)

    Dobry, T. J.; Walberg, G.

    2001-02-01

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

  6. Cost estimating Brayton and Stirling engines

    NASA Technical Reports Server (NTRS)

    Fortgang, H. R.

    1980-01-01

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

  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. A model regenerator for a Stirling cycle

    NASA Astrophysics Data System (ADS)

    Carolan, James

    2001-05-01

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

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. Component technology for Stirling power converters

    NASA Astrophysics Data System (ADS)

    Thieme, Lanny G.

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

  14. Stirling technology development at NASA GRC

    NASA Astrophysics Data System (ADS)

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

    2002-01-01

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

  15. 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

  16. 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

  17. NASA GRC Stirling Technology Development Overview

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2003-01-01

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

  18. Stirling Technology Development at NASA GRC. Revised

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  19. Stirling Technology Development at NASA GRC

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  20. NASA GRC Stirling Technology Development Overview

    NASA Astrophysics Data System (ADS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2003-01-01

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

  1. 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.

  2. HTC solar Stirling development Sunset Powerstation

    SciTech Connect

    Mitzel, M.; Leibfried, I.U.

    1995-11-01

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

  3. Analysis of an idealized Stirling thermocompressor

    SciTech Connect

    Kornhauser, A.A.

    1996-12-31

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

  4. Phase-angle controller for Stirling engines

    SciTech Connect

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

    1980-12-23

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

  5. 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.

  6. Two piston V-type Stirling engine

    SciTech Connect

    Corey, J.A.

    1987-01-06

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

  7. Heat exchanger for a Stirling engine

    SciTech Connect

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

    1987-05-05

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

  8. Identification of a Stirling engine's torque characteristics

    SciTech Connect

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

    1983-08-01

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

  9. Enhanced design for a miniature Stirling machine

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboro; Araoka, Katsumasa; Otaka, Toshio

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

  10. 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.

  11. 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.

  12. 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.

  13. Hydrogen Internal Combustion Stirling Engine

    NASA Astrophysics Data System (ADS)

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

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

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

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

    1991-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Tew, Roy C., Jr.

    1988-01-01

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

  16. 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.

  17. Piston rod seal for a Stirling engine

    SciTech Connect

    Shapiro, W.

    1984-01-31

    In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal. 3 figs.

  18. Stirling engine patents: international patent inventory

    SciTech Connect

    Newman, B.K.

    1983-09-01

    One hundred seventy-five years (1817-1982) of research and development (R and D) in Stirling-cycle engines is represented in this international inventory of patent applications. The following lists are included: assignor, assignee, patent numbers, US patent classification, and international patent classification. (MHR)

  19. 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.

  20. Materials technology for Stirling space power converters

    NASA Technical Reports Server (NTRS)

    Baggenstoss, William; Mittendorf, Donald

    1992-01-01

    This program was conducted in support of the NASA LeRC development of the Stirling power converter (SPC) for space power applications. The objectives of this contract were: (1) to perform a technology review and analyses to support the evaluation of materials issues for the SPC; (2) to evaluate liquid metal compatibility issues of the SPC; (3) to evaluate and define a transient liquid phase diffusion bonding (TLPDB) process for the SPC joints to the Udimet 720 heater head; and (4) to evaluate alternative (to the TLPDB) joining techniques. In the technology review, several aspects of the current Stirling design were examined including the power converter assembly process, materials joining, gas bearings, and heat exchangers. The supporting analyses included GLIMPS power converter simulation in support of the materials studies, and system level analysis in support of the technology review. The liquid metal compatibility study evaluated process parameters for use in the Stirling power converter. The alternative joining techniques study looked at the applicability of various joining techniques to the Stirling power converter requirements.

  1. 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.

  2. Stirling Power Convertors Demonstrated in Extended Operation

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    2005-01-01

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

  3. Two piston V-type Stirling engine

    DOEpatents

    Corey, John A.

    1987-01-01

    A two piston Stirling engine which includes a heat exchanger arrangement placing the cooler and regenerator directly adjacent the compression space for minimal cold duct volume; a sealing arrangement which eliminates the need for piston seals, crossheads and piston rods; and a simplified power control system.

  4. The Stirling Lesson-Sampling Instruments.

    ERIC Educational Resources Information Center

    White, D. R.

    A long-term Leverhulme Research Project was established at Stirling University in 1970 to investigate the potential of microteaching as a major ingredient in the preparation of graduate high school teachers in Scotland. Members of the research team developed systematic observation schedules for each of the skills, in order to sharpen the focus of…

  5. Quirks of Stirling's Approximation

    ERIC Educational Resources Information Center

    Macrae, Roderick M.; Allgeier, Benjamin M.

    2013-01-01

    Stirling's approximation to ln "n"! is typically introduced to physical chemistry students as a step in the derivation of the statistical expression for the entropy. However, naive application of this approximation leads to incorrect conclusions. In this article, the problem is first illustrated using a familiar "toy…

  6. Vibration Testing of an Operating Stirling Convertor

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    The NASA John H. Glenn Research Center and the U.S. Department of Energy are currently developing a Stirling convertor for use as an advanced spacecraft power system for future NASA deep-space missions. As part of this development, a Stirling Technology Demonstrator Convertor (TDC) was recently tested to verify its survivability and capability of withstanding its expected launch random vibration environment. The TDC was fully operational (producing power) during the random vibration testing. The output power of the convertor was measured during the testing, and these results are discussed in this paper. Numerous accelerometers and force gauges were also present which provided information on the dynamic characteristics of the TDC and an indication of any possible damage due to vibration. These measurements will also be discussed in this paper. The vibration testing of the Stirling TDC was extremely successful. The TDC survived all its vibration testing with no structural damage or functional performance degradation. As a result of this testing, the Stirling convertor's capability to withstand vibration has been demonstrated, enabling its usage in future spacecraft power systems.

  7. Piston rod seal for a Stirling engine

    DOEpatents

    Shapiro, Wilbur

    1984-01-01

    In a piston rod seal for a Stirling engine, a hydrostatic bearing and differential pressure regulating valve are utilized to provide for a low pressure differential across a rubbing seal between the hydrogen and oil so as to reduce wear on the seal.

  8. "Starfish" Heater Head For Stirling Engine

    NASA Technical Reports Server (NTRS)

    Vitale, N.

    1993-01-01

    Proposed "starfish" heater head for Stirling engine enables safe use of liquid sodium as heat-transfer fluid. Sodium makes direct contact with heater head but does not come in contact with any structural welds. Design concept minimizes number of, and simplifies nonstructural thermal welds and facilitates inspection of such welds.

  9. 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.

  10. 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.

  11. 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.

  12. Measurements with a recuperative superfluid Stirling refrigerator

    SciTech Connect

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

    1995-08-01

    A superfluid Stirling refrigerator cooled to 168 mK using a 4.9% {sup 3}He- {sup 4}He mixture and exhausting its waste heat at 383 mK. Cooling power versus temperature and speed is presented for 4.9%, 17%, and 36% mixtures. At the highest concentration, a dissipation mechanism of unknown origin is observed.

  13. Testing of a Stirling cycle cooler

    SciTech Connect

    Chen, F.C.; Keshock, E.G.; Murphy, R.W.

    1988-09-01

    Stirling cycle coolers have long been used as low temperature refrigeration devices. They are relatively compact, reliable, commercially available, and use helium as the working fluid. The Stirling cycle, in principle, can be used for household refrigeration and heat pumping applications as well. Currently, these applications are almost entirely provided by the vapor compression technology using chlorofluorocarbons (CFCs) as working fluids. It has been known that CFCs cause depletion of the ozone layer that protects the earth against harmful levels of ultraviolet radiation from the sun. A recent report of a ''hole'' in the ozone layer above Antarctica and of possible environmental and health consequences from ozone depletion aroused public attention. The urgent need to reduce the future used of CFCs should instigate investigation of non-CFC alternative technologies. The Stirling cooler technology, which does not use CFCs, could be a viable alternative. A laboratory test of the performance of a Stirling cooler is reported and its implications for household refrigeration are explored. 11 refs., 6 figs., 2 tabs.

  14. Stirling-Cycle Refrigerator Containing Piezoelectric Pumps

    NASA Technical Reports Server (NTRS)

    Jalink, Antony, Jr.; Hellbaum, R. F.

    1995-01-01

    Advanced Stirling-cycle cryogenic apparatus suitable for cooling sensitive infrared detectors to very low temperatures. Working fluid in refrigerator helium. Working fluid compressed and circulated by three piezoelectrically actuated diaphragm pumps offering advantages of greater reliability, relative simplicity, and lower cost.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. A Stirling engine with a liquid working substance

    NASA Astrophysics Data System (ADS)

    Swift, G. W.

    1989-06-01

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

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

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.

    2001-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Schifer, Nicholas A.; Oriti, Salvatore M.

    2013-01-01

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

  3. Composite Matrix Regenerator for Stirling Engines

    NASA Technical Reports Server (NTRS)

    Knowles, Timothy R.

    1997-01-01

    This project concerns the design, fabrication and testing of carbon regenerators for use in Stirling power convertors. Radial fiber design with nonmetallic components offers a number of potential advantages over conventional steel regenerators: reduced conduction and pressure drop losses, and the capability for higher temperature, higher frequency operation. Diverse composite fabrication methods are explored and lessons learned are summarized. A pulsed single-blow test rig has been developed that has been used for generating thermal effectiveness data for different flow velocities. Carbon regenerators have been fabricated by carbon vapor infiltration of electroflocked preforms. Performance data in a small Stirling engine are obtained. Prototype regenerators designed for the BP-1000 power convertor were fabricated and delivered to NASA-Lewis.

  4. Stirling engine supporting research and technology

    NASA Technical Reports Server (NTRS)

    Tomazic, W. A.

    1985-01-01

    The supporting research and technology effort is intended to provide technical support to the current engine program and also to investigate advanced concepts for the next generation of Stirling engines. Technical areas represented are: seals, materials, engine experiments, combustion, system analysis, cseramics, and tribology. A collage of more recent work in each area is presented. Under seals, analysis and some experimental data on the effect of wear on rod seal performance is presented. The material work described concerns the effect of water content on hydrogen permeation. Results of experiments with the Philips' Advenco engine are presented. A comparison is made of two combustor nozzles, an air atomizing and an ultrasonic atomizing nozzle. A new venture in systems analysis to provide more rigorous Stirling engine simulation is discussed. The results of hydrogen corrosion tests on silicon carbide are presented. Friction and wear tests on candidate materials for engine hot ring tests are discussed.

  5. Basic principles of the Stirling cycle

    NASA Astrophysics Data System (ADS)

    1983-03-01

    The basic principles of the Stirling cycle are outlined. From an elementary theory the general properties of the cycle are derived with a discussion of the most important losses. The performance of the fundamental and ideal (isothermal) cycle are described. The actual cycle, which differs from the ideal one by the occurrence of losses is also described. In the ideal Stirling cycle, the cold is produced by the reversible expansion of a gas. The gas performs a closed cycle, during which it is alternately compressed at ambient temperature in a compression space and expanded at the desired low temperature in an expansion space, thereby reciprocating between these spaces through one connecting duct, wherein a regenerator provides for the heat exchange between the outgoing and the returning gas flow. The problem of how to minimize the total sum of the losses is examined.

  6. Improved Stirling engine performance using jet impingement

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    Of the many factors influencing the performance of a Stirling engine, that of transferring the combustion gas heat into the working fluid is crucial. By utilizing the high heat transfer rates obtainable with a jet impingement heat transfer system, it is possible to reduce the flame temperature required for engine operation. Also, the required amount of heater tube surface area may be reduced, resulting in a decrease in the engine nonswept volume and a related increase in engine efficiency. A jet impingement heat transfer system was designed by Rasor Associates, Inc., and tested in the GPU-3 Stirling engine at the NASA Lewis Research Center. For a small penalty in pumping power (less than 0.5% of engine output) the jet impingement heat transfer system provided a higher combustion-gas-side heat transfer coefficient and a smoothing of heater temperature profiles resulting in lower combustion system temperatures and a 5 to 8% increase in engine power output and efficiency.

  7. Stirling Colgate and Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Lamb, Donald

    2014-10-01

    Even before the discovery of gamma-ray bursts (GRBs), Stirling Colgate proposed that bursts of x rays and gamma rays might be produced by a relativistic shock created in the supernova explosion of a massive star. We trace the scientific story of GRBs from their detection to the present, highlighting along the way Stirling's interest in them and his efforts to understand them. We summarize our current understanding that short, soft, repeating bursts are produced by magnetic neutron stars; short, hard bursts are produced by the mergers of neutron star-neutron star binaries; and long, hard bursts are produced by the core collapse of massive stars that have lost their hydrogen and helium envelopes. We then discuss some important open questions about GRBs and how they might be answered. We conclude by describing the recent serendipitous discovery of an x-ray burst of exactly the kind he proposed, and the insights into core collapse supernovae and GRBs that it provided.

  8. 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.

  9. 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.

  10. Construction of a thermoacoustic Stirling cooler

    NASA Astrophysics Data System (ADS)

    Ueda, Yuki; Biwa, Tetsushi; Yazaki, Taichi; Mizutani, Uichiro

    2003-05-01

    An efficient thermoacoustic prime mover has been built by Backhaus and Swift (Nature 339 (1999) 335). They have demonstrated that this engine produces an acoustic power with the thermal efficiency of 30%. We succeed in developing a thermoacoustic Stirling cooler as its application by inserting a regenerator inside the prime mover. Since this cooler has no moving parts and has a potential to be an efficient device, it is a powerful tool to generate low temperatures.

  11. Direct-Circulation Stirling-Cycle Refrigerator

    NASA Technical Reports Server (NTRS)

    Ellison, Woody; Kohuth, Randall, Sr.

    1995-01-01

    In proposed cryogenic system, cold working fluid (helium) circulated directly from Stirling-cycle refrigerator machinery through loop of tubing to provide 15 W of cooling power at temperature of 80 K to scientific instruments or other devices located at some distance from machinery. (Separation of cooled devices from machinery may be dictated by engineering requirements including, need to isolate cooled devices from vibrations of machinery.) Advantages include less complexity, smaller size, lighter weight, and lower power consumption.

  12. Cermet Coatings for Solar Stirling Space Power

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Raack, Taylor

    2004-01-01

    Cermet coatings, molecular mixtures of metal and ceramic are being considered for the heat inlet surface of a solar Stirling space power converter. This paper will discuss the solar absorption characteristics of as-deposited cermet coatings as well as the solar absorption characteristics of the coatings after heating. The role of diffusion and island formation, during the deposition process and during heating will also be discussed.

  13. Stirling Engine With Radial Flow Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Vitale, N.; Yarr, George

    1993-01-01

    Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.

  14. Sensitivity analysis of Stirling engine design parameters

    SciTech Connect

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

    1998-07-01

    In the preliminary Stirling engine design process, the values of some design parameters (temperature ratio, swept volume ratio, phase angle and dead volume ratio) have to be assumed; as a matter of fact it can be difficult to determine the best values of these parameters for a particular engine design. In this paper, a mathematical model is developed to analyze the sensitivity of engine's performance variations corresponding to variations of these parameters.

  15. High-Temperature Materials For Stirling Engines

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1990-01-01

    Heat-resistant piston rings and linings increase engine efficiency. Report discusses research on materials for piston rings and cylinder coatings in automotive Stirling engines. Data from tests show cobalt-based alloy, Stellite 6B, good choice for piston rings and PS200, plasma-sprayed metal-bonded chromium carbide matrix with dispersed solid lubricants, functions well as cylinder coating. Materials make it possible to place piston rings at tops of pistons ("hot" piston rings) instead of at cooler bottoms.

  16. Resistance Heater Helps Stirling-Engine Research

    NASA Technical Reports Server (NTRS)

    Hoehn, F. W.

    1982-01-01

    Stirling engine heater head consists of 18 double-turn coils of tubing, each of which is tightly wrapped with resistance-heating element, through which working gas flows. Coils form a toroid about periphery of heater-head body. With new resistance heater, total circuit resistance can be selected independently of tube geometry by changing size of wires and/or number of wire wraps around each tube.

  17. Optimization of an irreversible Stirling regenerative cycle

    NASA Astrophysics Data System (ADS)

    Aragón-González, G.; Cano-Bianco, M.; León-Galicia, A.; Rivera-Camacho, J. M.

    2015-01-01

    In this work a Stirling regenerative cycle with some irreversibilities is analyzed. The analyzed irreversibilities are located at the heat exchangers. They receive a finite amount of heat and heat leakage occurs between both reservoirs. Using this model, power and the efficiency at maximum power are obtained. Some optimal design parameters for the exchanger heat areas and thermal conductances are presented. The relation between the power, efficiency and the results obtained are shown graphically.

  18. Stirling engine with air working fluid

    DOEpatents

    Corey, John A.

    1985-01-01

    A Stirling engine capable of utilizing air as a working fluid which includes a compact heat exchange module which includes heating tube units, regenerator and cooler positioned about the combustion chamber. This arrangement has the purpose and effect of allowing the construction of an efficient, high-speed, high power-density engine without the use of difficult to seal light gases as working fluids.

  19. Reliability Issues in Stirling Radioisotope Power Systems

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin R.; Schreiber, Jeffrey G.

    2004-01-01

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

  20. 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.

  1. Reliability Issues in Stirling Radioisotope Power Systems

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey; Shah, Ashwin

    2005-01-01

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

  2. 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.

  3. 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.

  4. 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.

  5. Overheat Prevention in Solar-Powered Stirling Engines

    NASA Technical Reports Server (NTRS)

    Garrigus, W. E.; Pons, R. L.

    1982-01-01

    Proposed controller for solar-powered Stirling engine prevents engine from burning up when energy added by Sun exceeds that withdrawn by load. Head-temperature controller used existing electrical control unit of Stirling engine to regulate power output in response to head temperature. Power out-put is varied so keeps head temperature fairly constant.

  6. Solar Stirling receiver alternatives for the terrestrial solar application

    NASA Technical Reports Server (NTRS)

    Stearns, J.

    1986-01-01

    Concept studies have been completed for four dish-Stirling receivers, i.e., solar only and thermal storage receiver, each of which is either directly coupled or indirectly (heat pipe) coupled to the Stirling engine. The results of these studies are to be applied to systems benefit/cost analysis to determine the most desirable development approach.

  7. 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.)

  8. 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.

  9. Trends in dish-Stirling solar receiver designs

    SciTech Connect

    Diver, R.B.; Andraka, C.E.; Moreno, J.B.; Adkins, D.R.; Moss, T.A.

    1990-01-01

    The dish-Stirling solar energy system, because of its high efficiency, is a leading candidate for producing low-cost electric power from the sun. Dish-Stirling receiver design involves dealing with non-uniform and highly concentrated solar flux at high temperatures (700--800{degree}C) and, therefore, presents a variety of technical challenges. The technology is in the process of evolving from directly illuminated heater-head tube receivers'' to receivers that use refluxing (i.e., gravity assisted) liquid metals as an intermediate heat transfer fluid. Modern dish-Stirling development was initiated in the late 1970s by the Jet Propulsion Laboratory for the Department of Energy. The JPL technology development with United Stirling, Inc. involved the USAB 4.95 Stirling engine and directly illuminated heater-head tube receivers. This work eventually led to the successful demonstrations and world record efficiencies by Advanco Corp., and to the attempted commercialization of the technology by McDonnell Douglas Corp. The severe nature of concentrated solar flux and the potential advantages of heat-pipe technology have caused an evolution toward reflux'' receivers. These receivers are just beginning to be tested in the laboratory and integrated with dish-Stirling systems. In this paper, the history and current status of dish-Stirling receiver development are presented and discussed. The technical challenges to be addressed by the dish-Stirling community and the future plans at Sandia are outlined. 52 refs., 9 figs.

  10. Trends in dish-Stirling solar receiver designs

    NASA Astrophysics Data System (ADS)

    Diver, R. B.; Andraka, C. E.; Moreno, J. B.; Adkins, D. R.; Moss, T. A.

    The dish-Stirling solar energy system, because of its high efficiency, is a leading candidate for producing low cost electric power from the sun. Dish-Stirling receiver design involves dealing with non-uniform and highly concentrated solar flux at high temperatures (700 to 800 C) and, therefore, presents a variety of technical challenges. The technology is in the process of evolving from directly illuminated heater head tube receivers to receivers that use refluxing (i.e., gravity assisted) liquid metals as an intermediate heat transfer fluid. Modern dish-Stirling development was initiated in the late 1970s by the Jet Propulsion Laboratory for the Department of Energy. The JPL technology development with United Stirling, Inc. involved the USAB 4.95 Stirling engine and directly illuminated heater-head tube receivers. This work eventually led to the successful demonstrations and world record efficiencies by Advanco Corp., and to the attempted commercialization of the technology by McDonnell Douglas Corp. The severe nature of concentrated solar flux and the potential advantages of heat pipe technology have caused an evolution toward reflux receivers. These receivers are just beginning to be tested in the laboratory and integrated with dish-Stirling systems. In this paper, the history and current status of dish-Stirling receiver development are presented and discussed. The technical challenges to be addressed by the dish-Stirling community and the future plans at Sandia are outlined.

  11. Dish/Stirling for Department of Defense applications final report

    SciTech Connect

    Diver, R.B.; Menicucci, D.F.

    1997-03-01

    This report describes a Strategic Environmental Research and Development Program (SERDP) project to field a dish/Stirling system at a southwestern US military facility. This project entitled ``Dish/Stirling for DoD Applications`` was started in August 1993 and was completed in September 1996. The project`s objective was to assist military facilities to field and evaluate emerging environmentally sound and potentially economical dish/Stirling technology. Dish/Stirling technology has the potential to produce electricity at competitive costs while at the same time providing a secure and environmentally benign source of power. In accordance with the SERDP charter, this project leveraged a US Department of Energy (DOE) cost-shared project between Sandia National Laboratories and Cummins Power Generation, Inc. (CPG). CPG is a wholly owned subsidiary of Cummins Engine Company, a leading manufacturer of diesel engines. To accomplish this objective, the project called for the installation of a dish/Stirling system at a military facility to establish first-hand experience in the operation of a dish/Stirling system. To scope the potential DoD market for dish/Stirling technology and to identify the site for the demonstration, a survey of southwestern US military facilities was also conducted. This report describes the project history, the Cummins dish/Stirling system, results from the military market survey, and the field test results.

  12. 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.

  13. Stirling System Modeling for Space Nuclear Power Systems

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Johnson, Paul K.

    2008-01-01

    A dynamic model of a high-power Stirling convertor has been developed for space nuclear power systems modeling. The model is based on the Component Test Power Convertor (CTPC), a 12.5-kWe free-piston Stirling convertor. The model includes the fluid heat source, the Stirling convertor, output power, and heat rejection. The Stirling convertor model includes the Stirling cycle thermodynamics, heat flow, mechanical mass-spring damper systems, and the linear alternator. The model was validated against test data. Both nonlinear and linear versions of the model were developed. The linear version algebraically couples two separate linear dynamic models; one model of the Stirling cycle and one model of the thermal system, through the pressure factors. Future possible uses of the Stirling system dynamic model are discussed. A pair of commercially available 1-kWe Stirling convertors is being purchased by NASA Glenn Research Center. The specifications of those convertors may eventually be incorporated into the dynamic model and analysis compared to the convertor test data. Subsequent potential testing could include integrating the convertors into a pumped liquid metal hot-end interface. This test would provide more data for comparison to the dynamic model analysis.

  14. Stirling System Modeling for Space Nuclear Power Systems

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Johnson, Paul K.

    2007-01-01

    A dynamic model of a high-power Stirling convertor has been developed for space nuclear power systems modeling. The model is based on the Component Test Power Convertor (CTPC), a 12.5-kWe free-piston Stirling convertor. The model includes the fluid heat source, the Stirling convertor, output power and heat rejection. The Stirling convertor model includes the Stirling cycle thermodynamics, heat flow, mechanical mass-spring damper systems, and the linear alternator. The model was validated against test data. Both nonlinear and linear versions of the model were developed. The linear version algebraically couples two separate linear dynamic models; one model of the Stirling cycle and one model of the thermal system, through the pressure factors. Future possible uses of the Stirling system dynamic model are discussed. A pair of commercially available 1-kWe Stirling convertors is being purchased by NASA Glenn Research Center. The specifications of those convertors may eventually be incorporated into the dynamic model and analysis compared to the convertor test data. Subsequent potential testing could include integrating the convertors into a pumped liquid metal hot-end interface. This test would provide more data for comparison to the dynamic model analysis.

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  16. Commercialization of dish-Stirling solar terrestrial systems

    NASA Technical Reports Server (NTRS)

    Ross, Brad; Penswick, Barry; White, Maury; Cooper, Martin; Farbman, Gerald

    1990-01-01

    The requirements for dish-Stirling commercialization are described. The requirements for practical terrestrial power systems, both technical and economic, are described. Solar energy availability, with seasonal and regional variations, is discussed. The advantages and disadvantages of hybrid operation are listed. The two systems described use either a 25-kW free-piston Stirling hydraulic engine or a 5-kW kinematic Stirling engine. Both engines feature long-life characteristics that result from the use of welded metal bellows as hermetic seals between the working gas and the crankcase fluid. The advantages of the systems, the state of the technology, and the challenges that remain are discussed. Technology transfer between solar terrestrial Stirling applications and other Stirling applications is predicted to be important and synergistic.

  17. A Study of Regenerator for a Personal Stirling Refrigerator

    NASA Astrophysics Data System (ADS)

    Murakami, Kazuhiko; Otaka, Toshio; Sakamoto, Moriyoshi; Yamaguchi, Hajime; Ota, Masahiro

    Stirling cycle system is expected as a gentle system to the earth, because the working fluid is completely free from chlorine molecules. A regenerator is the most important element of the Stirling cycle system for the performances. Flow in a regenerator is very complicated because the regenerator is made of matrix. So we are studying about Stirling cycle systems, especially the regenerator for a personal Stirling refrigerator. In this report, flow in a regenerator for a personal Stirling refrigerators is studied by using an original experimental set-up. Flow velocities and pressures at the outside of a matrix in a regenerator were measured in a round pipe. Flow effects of inlet or outlet shape and area for a regenerator were examined in detail. Pressure loss were measured at sides of a regenerator and friction factors were expressed as empirical formulas for each conditions of inlet shape of regenerator or matrixes.

  18. Performance of the Southern California Edison Company Stirling dish

    SciTech Connect

    Lopez, C.W.; Stone, K.W.

    1993-10-01

    McDonnell Douglas Astronautics Company (MDAC) and United Stirling AB of Sweden (USAB) formed a joint venture in 1982 to develop and produce a Stirling dish solar generating system. In this report, the six year development and testing program continued by the Southern California Edison Company (SCE) is described. Each Stirling dish module consists of a sun tracking dish concentrator developed by the MDAC and a Stirling engine driven power conversion unit (PCU) developed by USAB. The Stirling dish system demonstrated twice the peak and daily solar-to-electric conversion efficiency of any other system then under development. This system continues to set the performance standard for solar to electric systems being developed in the early 1990`s. Test data are presented and used to estimate the performance of a commercial system.

  19. 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.

  20. Hybrid sodium heat pipe receivers for dish/Stirling systems

    SciTech Connect

    Laing, D.; Reusch, M.

    1997-12-31

    The design of a hybrid solar/gas heat pipe receiver for the SBP 9 kW dish/Stirling system using a United Stirling AB V160 Stirling engine and the results of on-sun testing in alternative and parallel mode will be reported. The receiver is designed to transfer a thermal power of 35 kW. The heat pipe operates at around 800 C, working fluid is sodium. Operational options are solar-only, gas augmented and gas-only mode. Also the design of a second generation hybrid heat pipe receiver currently developed under a EU-funded project, based on the experience gained with the first hybrid receiver, will be reported. This receiver is designed for the improved SPB/L. and C.-10 kW dish/Stirling system with the reworked SOLO V161 Stirling engine.

  1. Commercialization of dish-Stirling solar terrestrial systems

    NASA Astrophysics Data System (ADS)

    Ross, Brad; Penswick, Barry; White, Maury; Cooper, Martin; Farbman, Gerald

    The requirements for dish-Stirling commercialization are described. The requirements for practical terrestrial power systems, both technical and economic, are described. Solar energy availability, with seasonal and regional variations, is discussed. The advantages and disadvantages of hybrid operation are listed. The two systems described use either a 25-kW free-piston Stirling hydraulic engine or a 5-kW kinematic Stirling engine. Both engines feature long-life characteristics that result from the use of welded metal bellows as hermetic seals between the working gas and the crankcase fluid. The advantages of the systems, the state of the technology, and the challenges that remain are discussed. Technology transfer between solar terrestrial Stirling applications and other Stirling applications is predicted to be important and synergistic.

  2. Performance of the Southern California Edison Company Stirling dish

    NASA Astrophysics Data System (ADS)

    Lopez, C. W.; Stone, K. W.

    1993-10-01

    McDonnell Douglas Astronautics Company (MDAC) and United Stirling AB of Sweden (USAB) formed a joint venture in 1982 to develop and produce a Stirling dish solar generating system. In this report, the six year development and testing program continued by the Southern California Edison Company (SCE) is described. Each Stirling dish module consists of a sun tracking dish concentrator developed by the MDAC and a Stirling engine driven power conversion unit (PCU) developed by USAB. The Stirling dish system demonstrated twice the peak and daily solar-to-electric conversion efficiency of any other system then under development. This system continues to set the performance standard for solar to electric systems being developed in the early 1990's. Test data are presented and used to estimate the performance of a commercial system.

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

    NASA Astrophysics Data System (ADS)

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

    2002-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  6. 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.

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

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.

    2002-01-01

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

  8. Update on the NASA GRC Stirling Technology Development Project

    NASA Technical Reports Server (NTRS)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2000-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  10. 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.

  11. The 4 K Stirling cryocooler demonstration

    NASA Technical Reports Server (NTRS)

    Stacy, W. Dodd

    1992-01-01

    This report briefly summarizes the results and conclusions from an SBIR program intended to demonstrate an innovative Stirling cycle cryocooler concept for efficiently lifting heat from 4 K. Refrigeration at 4 K, a temperature useful for superconductors and sensitive instruments, is beyond the reach of conventional regenerative thermodynamic cycles due to the rapid loss of regenerator matrix heat capacity at temperatures below about 20 K. To overcome this fundamental limit, the cryocooler developed under this program integrated three unique features: recuperative regeneration between the displacement gas flow streams of two independent Stirling cycles operating at a 180 degree phase angle, tailored distortion of the two expander volume waveforms from sinusoidal to perfectly match the instantaneous regenerator heat flux from the two cycles and thereby unload the regenerator, and metal diaphragm working volumes to promote near isothermal expansion and compression processes. Use of diaphragms also provides unlimited operating life potential and eliminates bearings and high precision running seals. A phase 1 proof-of-principle experiment demonstrated that counterflow regenerator operation between 77 K and 4 K increases regenerator effectiveness by minimizing metal temperature transient cycling. In phase 2, a detailed design package for a breadboard cryocooler was completed. Fabrication techniques were successfully developed for manufacturing high precision miniature parallel plate recuperators, and samples were produced and inspected. Process development for fabricating suitably flat diaphragms proved more difficult and expensive than anticipated, and construction of the cryocooler was suspended at a completion level of approximately 75%. Subsequent development efforts on other projects have successfully overcome diaphragm fabrication difficulties, and alternate funding is currently being sought for completion and demonstration testing of the 4 K Stirling cryocooler.

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

    NASA Astrophysics Data System (ADS)

    Schreiber, Jeffrey G.; Skupinski, Robert C.

    2002-01-01

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

  13. Basic dynamics of split Stirling refrigerators

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

    The basic features of the split Stirling refrigerator, driven by a linear compressor, are described. Friction of the compressor piston and of the regenerator, and the viscous losses due to the gas flow through the regenerator matrix are taken into account. The temperature at the cold end is an input parameter. The general equations are derived which are subsequently treated in the harmonic approximation. Examples are given of application of the relations for describing optimum-performance conditions as well as the interrelationship between cooler and heat-engine operation.

  14. 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.

  15. 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.

  16. 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.

  17. In-line stirling energy system

    DOEpatents

    Backhaus, Scott N.; Keolian, Robert

    2011-03-22

    A high efficiency generator is provided using a Stirling engine to amplify an acoustic wave by heating the gas in the engine in a forward mode. The engine is coupled to an alternator to convert heat input to the engine into electricity. A plurality of the engines and respective alternators can be coupled to operate in a timed sequence to produce multi-phase electricity without the need for conversion. The engine system may be operated in a reverse mode as a refrigerator/heat pump.

  18. 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.

  19. A general simulation model for Stirling cycles

    SciTech Connect

    Schulz, S.; Schwendig, F.

    1996-01-01

    A mathematical model for the calculation of the Stirling cycle and of similar processes is presented. The model comprises a method to reproduce schematically any kind of process configuration, including free piston engines. The differential balance equations describing the process are solved by a stable integration algorithm. Heat transfer and pressure loss are calculated by using new correlations, which consider the special conditions of the periodic compression/expansion respectively of the oscillating flow. A comparison between experimental data achieved by means of a test apparatus and calculated data shows a good agreement.

  20. 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.

  1. 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.

  2. A feasibility assessment of magnetic bearings for free-piston Stirling space power converters

    NASA Astrophysics Data System (ADS)

    Curwen, Peter W.; Rao, Dantam K.; Wilson, Donald R.

    1992-06-01

    This report describes a design and analysis study performed by Mechanical Technology Incorporated (MTI) under NASA Contract NAS3-26061. The objective of the study was to assess the feasibility and efficacy of applying magnetic bearings to free-piston Stirling-cycle power conversion machinery of the type currently being evaluated for possible use in long-term space missions. The study was performed for a 50-kWe Reference Stirling Space Power Converter (RSSPC) system consisting of two 25-kWe free-piston Stirling engine modules. Two different versions of the RSSPC engine modules have been defined under NASA Contract NAS3-25463. These modules currently use hydrostatic gas bearings to support the reciprocating displacer and power piston assemblies. Results of this study show that active magnetic bearings of the attractive electromagnetic type are technically feasible for RSSPC application provided that wire insulation with 60,000-hr life capability at 300 C can be developed for the bearing coils. From a design integration standpoint, both versions of the RSSPC were found to be conceptually amenable to magnetic support of the power piston assembly. However, only one version of the RSSPC was found to be amendable to magnetic support of the displacer assembly. Unacceptable changes to the basic engine design would be required to incorporate magnetic displacer bearings into the second version. Complete magnetic suspension of the RSSPC can potentially increase overall efficiency of the Stirling cycle power converter by 0.53 to 1.4 percent (0.15 to 0.4 efficiency points). Magnetic bearings will also overcome several operational concerns associated with hydrostatic gas bearing systems. However, these advantages are accompanied by a 5 to 8 percent increase in specific mass of the RSSPC, depending on the RSSPC version employed. Additionally, magnetic bearings are much more complex, both mechanically and particularly electronically, than hydrostatic bearings. Accordingly, long

  3. A feasibility assessment of magnetic bearings for free-piston Stirling space power converters

    NASA Technical Reports Server (NTRS)

    Curwen, Peter W.; Rao, Dantam K.; Wilson, Donald R.

    1992-01-01

    This report describes a design and analysis study performed by Mechanical Technology Incorporated (MTI) under NASA Contract NAS3-26061. The objective of the study was to assess the feasibility and efficacy of applying magnetic bearings to free-piston Stirling-cycle power conversion machinery of the type currently being evaluated for possible use in long-term space missions. The study was performed for a 50-kWe Reference Stirling Space Power Converter (RSSPC) system consisting of two 25-kWe free-piston Stirling engine modules. Two different versions of the RSSPC engine modules have been defined under NASA Contract NAS3-25463. These modules currently use hydrostatic gas bearings to support the reciprocating displacer and power piston assemblies. Results of this study show that active magnetic bearings of the attractive electromagnetic type are technically feasible for RSSPC application provided that wire insulation with 60,000-hr life capability at 300 C can be developed for the bearing coils. From a design integration standpoint, both versions of the RSSPC were found to be conceptually amenable to magnetic support of the power piston assembly. However, only one version of the RSSPC was found to be amendable to magnetic support of the displacer assembly. Unacceptable changes to the basic engine design would be required to incorporate magnetic displacer bearings into the second version. Complete magnetic suspension of the RSSPC can potentially increase overall efficiency of the Stirling cycle power converter by 0.53 to 1.4 percent (0.15 to 0.4 efficiency points). Magnetic bearings will also overcome several operational concerns associated with hydrostatic gas bearing systems. However, these advantages are accompanied by a 5 to 8 percent increase in specific mass of the RSSPC, depending on the RSSPC version employed. Additionally, magnetic bearings are much more complex, both mechanically and particularly electronically, than hydrostatic bearings. Accordingly, long

  4. Linear hydraulic drive system for a Stirling engine

    SciTech Connect

    Walsh, M.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. 2 figs.

  5. Ceramic applications in the advanced Stirling automotive engine

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    The requirements of the ideal Stirling cycle, as well as basic types of practical engines are described. Advantages, disadvantages, and problem areas of these Stirling engines are discussed. The potential for ceramic components is also considered. Currently ceramics are used in only two areas, the air preheater and insulating tiles between the burner and the heater head. For the advanced Stirling engine to achieve high efficiency and low cost, the principal components are expected to be made from ceramic materials, including the heater head, air preheater, regenerator, the burner and the power piston. Supporting research and technology programs for ceramic component development are briefly described.

  6. 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.

  7. Progress of Stirling cycle analysis and loss mechanism characterization

    NASA Technical Reports Server (NTRS)

    Tew, R. C., Jr.

    1986-01-01

    An assessment of Stirling engine thermodynamic modeling and design codes shows a general deficiency; this deficiency is due to poor understanding of the fluid flow and heat transfer phenomena that occur in the oscillating flow and pressure level environment within the engines. Stirling engine thermodynamic loss mechanisms are listed. Several experimental and computational research efforts now underway to characterize various loss mechanisms are reviewed. The need for additional experimental rigs and rig upgrades is discussed. Recent developments and current efforts in Stirling engine thermodynamic modeling are also reviewed.

  8. Heat pipe gas combustion system endurance test for Stirling engine

    NASA Astrophysics Data System (ADS)

    Mahrle, P.

    1990-12-01

    Stirling Thermal Motors, Inc. has been developing a general purpose Heat Pipe Gas Combustion (HPGC) system 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. The principal component 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. Given here are the test results of the endurance tests run on a Gas Fired Stirling Engine (GFSE).

  9. 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.

  10. 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.

  11. 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.

  12. Potential impacts of Brayton and Stirling cycle engines

    NASA Astrophysics Data System (ADS)

    Heft, R. C.

    1980-11-01

    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.

  13. 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.

  14. Overview of NASA supported Stirling thermodynamic loss research

    NASA Technical Reports Server (NTRS)

    Tew, Roy C.; Geng, Steven M.

    1992-01-01

    NASA is funding research to characterize Stirling machine thermodynamic losses. NASA's primary goal is to improve Stirling design codes to support engine development for space and terrestrial power. However, much of the fundamental data is applicable to Stirling cooling and heat pump applications. The research results are reviewed. Much was learned about oscillating flow hydrodynamics, including laminar/turbulent transition, and tabulated data was documented for further analysis. Now, with a better understanding of the oscillating flow field, it is time to begin measuring the effects of oscillating flow and oscillating pressure level on heat transfer in heat exchanger flow passages and in cylinders.

  15. Status of NASA's Stirling space power converter program

    NASA Astrophysics Data System (ADS)

    Dudenhoefer, James E.; Winter, Jerry M.

    An overview is presented of the NASA free-piston stirling space power converter technology program. The authors discuss Stirling experience in space and progress toward 1050 K and 1300 K Stirling space power converters. Fabrication is nearly completed for the 1050 K component test power converter (CTPC); results of motoring tests of the cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing and predictive methodologies. The authors provide an update of progress in some of these technologies.

  16. 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.

  17. Stirling engine developments for solar and other renewable energy resources in the 1980's

    SciTech Connect

    Percival, W.H.; Rosenquist, K.

    1982-06-01

    This paper presents Stirling engine developments over the past three years by United Stirling of Sweden, for applications to solar electric power and with other renewable energy resources, such as biomass fuel. The modern Stirling engine is described as well as the new 4 cylinder, double-acting designs from United Stirling. The Dish/Stirling electric power program at JPL/Edwards and Georgia Tech is discussed. Biomass combustion programs are reported, including in-house work and DOE activities. Wood fuel combustion problems are discussed. The potential for the 1980's of the Stirling in the mega-watt size is presented and applications of ceramic technology are explored.

  18. Isotope powered stirling generator for terrestrial applications

    NASA Astrophysics Data System (ADS)

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

    1995-01-01

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

  19. Isotope powered stirling generator for terrestrial applications

    SciTech Connect

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

    1995-01-20

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

  20. Dish stirling solar receiver combustor test program

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    The operational and energy transfer characteristics of the Dish Stirling Solar Receiver (DSSR) combustor/heat exchanger system was evaluated. The DSSR is designed to operate with fossil fuel augmentation utilizing a swirl combustor and cross flow heat exchanger consisting of a single row of 4 closely spaced tubes that are curved into a conical shape. The performance of the combustor/heat exchanger system without a Stirling engine was studied over a range of operating conditions and output levels using water as the working fluid. Results show that the combustor may be started under cold conditions, controlled safety, and operated at a constant air/fuel ratio (10 percent excess air) over the required range of firing rates. Furthermore, nondimensional heat transfer coefficients based on total heat transfer are plotted versus Reynolds number and compared with literature data taken for single rows of closely spaced tubes perpendicular to cross flow. The data show enhanced heat transfer for the present geometry and test conditions. Analysis of the results shows that the present system meets specified thermal requirements, thus verifying the feasibility of the DSSR combustor design for final prototype fabrication.

  1. Regenerator optimization for Stirling cycle refrigeration

    SciTech Connect

    Colgate, S.A.; Petschek, A.G.

    1993-08-01

    A cryogenic regenerator for a Stirling cycle is designed using a fractional loss or entropy gain as the criterion of performance. The gas losses are treated separately from heat storage medium losses. For the optimum channel flow nonturbulent design, the maximization of heat transfer from the gas to the wall and the minimization of entropy production by friction leads to a gas flow velocity criterion of sound speed times loss fraction. This velocity with a given frequency leads to a Stirling cycle dead volume ratio and consequently a channel of specified length and width. The thermal properties of the channel wall must then accommodate this cyclic heat flow without substantially increasing the loss fraction. It is found that stainless steel or plastics are adequate for 30 to 300 K, but that lower temperature stages 4 to 30 K require either a special lead alloy of moderate conductivity or a segmented anisotropic construction of alternate highly conducting lead layers and alternate insulating glass or epoxy fiber glass spacers. An overall efficiency of {congruent} 50% of Carnot is predicted at a frequency of 30 Hz and a pressure of one atmosphere.

  2. Preliminary SP-100/Stirling heat exchanger designs

    SciTech Connect

    Schmitz, P.; Tower, L.; Dawson, R.; Blue, B.; Dunn, P.

    1994-09-01

    Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC`s are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.

  3. Isotope powered Stirling generator for terrestrial applications

    SciTech Connect

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

    1995-01-01

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

  4. Micro-Miniature Split Stirling Linear Crycooler

    NASA Astrophysics Data System (ADS)

    Veprik, A.; Zehtzer, S.; Vilenchik, H.; Pundak, N.

    2010-04-01

    Novel tactics for rescue, surveillance, reconnaissance, force protection, perimeter security, navigation and targeting often involve the use of miniature infrared imagers, where the cooled imaging systems are known to be superior to their uncooled rivals in terms of working range, resolution and ability to distinguish/track fast moving objects in dynamic infrared scenes. The latest technological advances in industrial applications of high-temperature infrared detectors have spurred the development of linearly driven, long life, dynamically quiet and aurally undetectable micro-miniature split Stirling linear cryogenic coolers. Recent progress in designing highly efficient "moving magnet" resonant linear actuators and dedicated smart electronics have enabled further improvements to the cooler's size, weight, power consumption, cooldown time and ownership costs. The authors report on the development of a novel micro-miniature split Stirling linear cryogenic cooler, where, by means of increasing the driving frequency up to 90 Hz, it appeared possible to shorten the cold finger to 19 mm. The cooler was specifically designed to cool a new generation of 130 K infrared detectors for portable infrared imagers, where compactness, low steady-state power consumption, fast cool-down time, vibration export and aural stealth are of primary concern.

  5. Reliability of Radioisotope Stirling Convertor Linear Alternator

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  6. Preliminary SP-100/Stirling heat exchanger designs

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul; Tower, Leonard; Dawson, Ronald; Blue, Brian; Dunn, Pat

    1993-01-01

    Analytic modeling of several heat exchanger concepts to couple the SP-100 nuclear reactor primary lithium loop and the Space Stirling Power Convertor (SSPC) was performed. Four 25 kWe SSPC's are used to produce the required 100 kW of electrical power. This design work focused on the interface between a single SSPC and the primary lithium loop. Manifolding to separate and collect the four channel flow was not modeled. This work modeled two separate types of heat exchanger interfaces (conductive coupling and radiative coupling) to explore their relative advantages and disadvantages. The minimum mass design of the conductively coupled concepts was 18 kg or 0.73 kg/kWe for a single 25 kWe convertor. The minimum mass radiatively coupled concept was 41 kg or 1.64 kg/kWe. The direct conduction heat exchanger provides a lighter weight system because of its ability to operate the Stirling convertor evaporator at higher heat fluxes than those attainable by the radiatively coupled systems. Additionally the conductively coupled concepts had relatively small volumes and provide potentially simpler assembly. Their disadvantages were the tight tolerances and material joining problems associated with this refractory to superalloy interface. The advantages of the radiatively coupled designs were the minimal material interface problems.

  7. 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.

  8. 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.

  9. 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.

  10. Design of Stirling-driven vapor-compression system

    SciTech Connect

    Kagawa, N.

    1998-07-01

    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 because of their potential to save energy. Especially, there are many environmental merits of Stirling-driven vapor-compression (SDVC) systems. This paper introduces a design method for the SDVC based on reliable mathematical methods for Stirling and Rankine cycles with reliable thermophysical information for refrigerants. The model treats a kinematic Stirling engine and a scroll compressor coupled by a belt. Some experimental coefficients are used to formulate the SDVC items. The obtained results show the performance behavior of the SDVC in detail. The measured performance of the actual system agrees with the calculated results. Furthermore, the calculated results indicate attractive SDVC performance using alternative refrigerants.

  11. Linear moving magnet motor/generator for Stirling engines

    NASA Astrophysics Data System (ADS)

    Shtrikman, S.; Urieli, I.

    Free piston Stirling cycle machines have many inherent advantages, however suffer from the difficulties of extracting power output and controllability of the free displacer, which is usually driven by gas pressure forces. Modern rare earth samarium cobalt magnets allow the use of moving magnet linear electrical devices. This paper discusses the development and testing of moving magnet devices designed specifically for use with Stirling engines, both for generating electricity and for driving the displacer piston. The generator was used as an output stage of a free piston Stirling engine, and is capable of delivering a power of 500 watts at an estimated efficiency of about 90%. The motor was used to drive the displacer of the same Stirling engine. It was found to be completely controllable in amplitude, phase, and mean position. The relative merits of moving magnet linear motor/generators are discussed.

  12. Overview of DOE's large stationary Stirling engine development program

    NASA Astrophysics Data System (ADS)

    Uherka, K. L.; Holtz, R. E.; Bunker, W.

    This paper summarizes the results to date of a program, sponsored by DOE's Office of Fossil Energy, to develop large stationary Stirling engine power systems. Primary applications for such power plants include cogeneration and total energy systems, with a major advantage being their ability to employ solid coal and other non-scarce fuels in an environmentally acceptable manner. The major effort in the Stirling engine development program was an industry-based design competition, involving three independent contractual teams. Conceptual designs for state-of-the-art coal-fired Stirling engine systems were developed and all three design teams recommended development of 373 kW modules as base units, which can be coupled together to form individual Stirling engines up to 2238 kW in size. Heat transport system design concepts were also developed for integrating engine hot-end sections with coal combustors.

  13. 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.

  14. 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%. PMID:16996100

  15. 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.

  16. Stirling, near-ambient temperature refrigerators - Innovative compact designs

    NASA Astrophysics Data System (ADS)

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

    Opportunities for the development and application of 'near-ambient' temperature refrigerating systems in connection with public concern over the impact of Freon refrigerants on the earth's ozone layer are examined. Previous work is reviewed, and recent innovative concepts and designs for compact Stirling refrigerators that could be the basis for alternatives for Freon-free refrigeration are presented. The advantages offered by Stirling refrigerators are high thermodynamic performance, simplicity, compactness, low weight and low cost.

  17. 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.

  18. 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

  19. 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.

  20. Development of a Stirling System Dynamic Model With Enhanced Thermodynamics

    NASA Technical Reports Server (NTRS)

    Regan, Timothy F.; Lewandowski, Edward J.

    2005-01-01

    The Stirling Convertor System Dynamic Model developed at NASA Glenn Research Center is a software model developed from first principles that includes the mechanical and mounting dynamics, the thermodynamics, the linear alternator, and the controller of a free-piston Stirling power convertor, along with the end user load. As such it represents the first detailed modeling tool for fully integrated Stirling convertor-based power systems. The thermodynamics of the model were originally a form of the isothermal Stirling cycle. In some situations it may be desirable to improve the accuracy of the Stirling cycle portion of the model. An option under consideration is to enhance the SDM thermodynamics by coupling the model with Gedeon Associates Sage simulation code. The result will be a model that gives a more accurate prediction of the performance and dynamics of the free-piston Stirling convertor. A method of integrating the Sage simulation code with the System Dynamic Model is described. Results of SDM and Sage simulation are compared to test data. Model parameter estimation and model validation are discussed.

  1. Stirling Isotope Power Systems for Stationary and Mobile Lunar Applications

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    The NASA Exploration Systems Architecture Study (ESAS) places a significant emphasis on the development of a wide range of capabilities on the lunar surface as a stepping-stone to further space exploration. An important aspect of developing these capabilities will be the availability of reliable, efficient, and low-mass power systems to support both stationary and mobile applications. One candidate system to provide electrical power is made by coupling the General Purpose Heat Source (GPHS) with a high-performance Stirling convertor. In this paper we explore the practical power range of GPHS/Stirling convertor systems all with conductively coupled hot-end designs for use on the lunar surface. Design and off-design operations during the life of the convertor are studied in addition to considering these varying conditions on system. Unique issues concerning Stirling convertor configurations, integration of the GPHS with the Stirling convertor, controller operation, waste heat rejection, and thermal protection are explored. Of particular importance in the evaluation process is a thorough understanding of the interactions between the wide range of unique lunar environments and the selection of key systems operating characteristics and the power systems design. Additionally, as power levels rise the interface between the GPHS and Stirling and the Stirling and the radiator begins to dominate system mass and material selection becomes more important.

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

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  3. Sodium Variable Conductance Heat Pipe for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  4. Overview of NASA GRC Stirling Technology Development

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey; Thieme, Lanny

    2003-01-01

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

  5. 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.

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  8. A thermoacoustic-Stirling hybrid heat engine

    NASA Astrophysics Data System (ADS)

    Backhaus, Scott

    2000-03-01

    By combining the thermodynamic reversibility of the Stirling cycle and the simplicity of thermoacoustic heat engines, a new type of hybrid heat engine has been developed. It has no moving parts and converts heat into acoustic work at 42% of the Carnot efficiency, a 50% increase over other no-moving-parts heat engines. By carefully shaping crucial components, boundary-layer processes and hydrodynamic end effects are used to suppress the acoustic streaming that would otherwise seriously degrade the engine performance. Streaming suppression is clearly demonstrated by measurements of temperature distributions and heat flows within the engine. Analysis of loss mechanisms suggest the path of future research on these engines.

  9. 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.

  10. High performance Split-Stirling cooler program

    NASA Astrophysics Data System (ADS)

    Meeker, R. P.

    1982-09-01

    This report describes the physical characteristics of the final design configuration of the 1 Watt Split-Stirling Cryogenic Cooler. Qualification testing included evaluation of the 1.0 Watt Cryogenic Cooler under the following conditions: Performance tests over the temperature range of -40 degrees C to +55 degrees C; High and Low Temperature Shock Tests; Mechanical Shock Tests; Sinsoidal Vibration; Self-Induced Vibration; Acoustical Testing; and 1000-Hour Mean Time Between Failure Life Tests. The cryogenic cooler design consists of a motor and compressor assembly, and a remote expander assembly, interconnected by a stainless steel capillary line. The system is nominally a 18.5 VDC, 60 Watt cooler and has a maximum weight of 4 pounds. This report summarizes the results of the performance, environmental and life qualification tests conducted under the contract and provides supporting data for each of the test categories.

  11. Solar Stirling for Deep Space Applications

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    1999-01-01

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

  12. 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.

  13. The Zimmerman-Stirling cryogenic cooler

    SciTech Connect

    Clarke, M.A.; Amiri-Samokey, H.; Taylor, D.R.

    1983-08-01

    The development of low power, superconductive, electronic components has led to the requirement for compact, low input, refrigeration devices generally called cryogenic coolers. The use of a reversed Stirling cycle has been reported, using helium as the working fluid and a simple form of gap regeneration, to achieve temperatures of 9K at high efficiency. As an undergraduate student project, a test rig was developed at RNEC Manadon to investigate the construction of such a device with its associated drive mechanism, using the basic dimensions available from the literature. The extremely low temperatures have not been produced when the rig is started up from room temperature with no precooling but some success has been found in tests using air as the working fluid.

  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. Overview of NASA GRC Stirling Technology Development

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.

    2004-01-01

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

  16. Development of Advanced Stirling Radioisotope Generator for Space Exploration

    NASA Astrophysics Data System (ADS)

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

    2007-01-01

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

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. Design and Fabrication of a Stirling Thermal Vacuum Test

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Schreiber, Jeffrey G.

    2004-01-01

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

  2. 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.

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  4. Vibration Test Demonstrated Dynamic Capability of an Operating Stirling Convertor

    NASA Technical Reports Server (NTRS)

    Hughes, William O.

    2001-01-01

    The NASA Glenn Research Center and the U.S. Department of Energy are currently developing a high-efficiency, long-life, free piston Stirling convertor for use as an advanced spacecraft power system for future NASA missions. As part of this development, a Stirling Technology Demonstrator Converter (TDC), developed by Stirling Technology Company for the Department of Energy, was vibration tested at Glenn's Structural Dynamics Laboratory in November and December 1999. This testing demonstrated that the Stirling TDC is able to withstand the harsh random vibration (20 to 2000 Hz) seen during a typical spacecraft launch and to survive with no structural damage or functional power performance degradation, thereby enabling its use in future spacecraft power systems. Glenn and Stirling personnel conducted tests on a single 55 We TDC. The purpose was to characterize the TDC's structural response to vibration and to determine if the TDC could survive the vibration criteria established by the Jet Propulsion Laboratory for launch environments. The TDC was operated at full-stroke and full power conditions during the vibration testing.

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

    NASA Astrophysics Data System (ADS)

    Kirillov, E. Ya.; 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.

  6. 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.

  7. Kinematic Stirling engine as an energy conversion subsystem for paraboloidal dish solar thermal power plants

    SciTech Connect

    Bowyer, J.M.

    1984-04-15

    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 has been estimated. Results obtained by elementary cycle analyses have been 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 has been given to other Stirling engine criteria such as durability, reliability, and serviceability. Production costs have not been considered here.

  8. 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.

  9. 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.}

  10. 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.

  11. 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.

  12. Heat transfer measurements for Stirling machine cylinders

    NASA Technical Reports Server (NTRS)

    Kornhauser, Alan A.; Kafka, B. C.; Finkbeiner, D. L.; Cantelmi, F. C.

    1994-01-01

    The primary purpose of this study was to measure the effects of inflow-produced heat turbulence on heat transfer in Stirling machine cylinders. A secondary purpose was to provide new experimental information on heat transfer in gas springs without inflow. The apparatus for the experiment consisted of a varying-volume piston-cylinder space connected to a fixed volume space by an orifice. The orifice size could be varied to adjust the level of inflow-produced turbulence, or the orifice plate could be removed completely so as to merge the two spaces into a single gas spring space. Speed, cycle mean pressure, overall volume ratio, and varying volume space clearance ratio could also be adjusted. Volume, pressure in both spaces, and local heat flux at two locations were measured. The pressure and volume measurements were used to calculate area averaged heat flux, heat transfer hysteresis loss, and other heat transfer-related effects. Experiments in the one space arrangement extended the range of previous gas spring tests to lower volume ratio and higher nondimensional speed. The tests corroborated previous results and showed that analytic models for heat transfer and loss based on volume ratio approaching 1 were valid for volume ratios ranging from 1 to 2, a range covering most gas springs in Stirling machines. Data from experiments in the two space arrangement were first analyzed based on lumping the two spaces together and examining total loss and averaged heat transfer as a function of overall nondimensional parameter. Heat transfer and loss were found to be significantly increased by inflow-produced turbulence. These increases could be modeled by appropriate adjustment of empirical coefficients in an existing semi-analytic model. An attempt was made to use an inverse, parameter optimization procedure to find the heat transfer in each of the two spaces. This procedure was successful in retrieving this information from simulated pressure-volume data with artificially

  13. Progress toward the evolution of a Stirling space engine

    NASA Technical Reports Server (NTRS)

    Alger, Donald L.

    1987-01-01

    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/linear alternator technolgy 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.

  14. 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.

  15. Phase 1 results from the Stirling-powered vehicle project

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.

    1988-01-01

    The NASA Technology Utilization (TU) Office is sponsoring a multiyear, multiphase demonstration program to assess the technology developed under the DOE/NASA automotive Stirling engine (ASE) program with engines installed in various Air Force vehicles while being evaluated by independent third parties under realistic conditions. This paper reviews the operational history of Phase 1 with a Mod 1 Stirling engine installed in an Air Force multistop van in a variety of missions. Ten months of operation were with Air Force personnel at Langley Air Force Base, Virginia, where over 1100 hr and 4000 mi were logged on the Langley flight line. The Stirling-powered van operated on unleaded gasoline, JP-4 aircraft fuel, and diesel fuel at Langley Air Force Base. Two months of operation were completed with Deere and Company personnel in the Moline, Illinois area where over 175 hr and 2650 mi were logged on a Deere mail delivery route.

  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. Progress toward the evolution of a Stirling Space Engine

    NASA Technical Reports Server (NTRS)

    Alger, Donald L.

    1988-01-01

    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/linear 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.

  18. Design of a preprototype Stirling Laboratory Research Engine

    NASA Technical Reports Server (NTRS)

    Hoehn, F. W.; Mcdougal, A. R.

    1978-01-01

    A description is given for the design and fabrication of a first generation, preprototype Stirling Laboratory Research Engine. The engine represents the first step in providing a research tool to be used to support the development of a broad range of analytical modeling and experimental efforts, and to evaluate new approaches to the design of components for Stirling engines. The test engine is a horizontally-opposed, two-piston, single-acting machine with a dual crankshaft drive mechanism. The preprototype engine is rated at 10 kW and was designed for maximum modularity. The long term objective of the project is to provide a proven design of a standardized test engine, which can be commercially produced, for national research on Stirling cycle machines.

  19. Preliminary test results with a Stirling Laboratory Research Engine

    NASA Technical Reports Server (NTRS)

    Hoehn, F. W.; Nguyen, B. D.; Schmit, D. D.

    1979-01-01

    The Jet Propulsion Laboratory has designed, assembled, and initiated testing of a Stirling Laboratory Research Engine (SLRE). This preprototype engine provides a research tool to support the development of a broad range of analytical modeling and experimental efforts. The SLRE is a horizontally opposed, two-piston, single-acting Stirling engine with a split crankshaft drive mechanism. The paper discusses the preliminary results obtained during engine motoring tests and compares these results with two different analytical prediction models. Comparisons are made between experiment, the classical Schmidt analysis, and the JPL Stirling Cycle Analysis Model (SCAM). SCAM is a computerized one-dimensional, cyclic, compressible flow model of the SLRE and consists of a compilation of individual component subroutines. The formulation and current state of development of the SCAM program is briefly described.

  20. Evaluation of potential military applications of stirling engines

    NASA Astrophysics Data System (ADS)

    Oelrich, Ivan C.; Riddell, Frederick R.

    1988-07-01

    This paper reports on the potential military applications of the Stirling engine. In the applications considered here, the major advantages cited for the Stirling engine are multifuel capability, efficiency, and low noise levels. These potential advantages are small compared to current diesels. Diesels are already able to burn broadcut fuels, have high efficiency, and can be adequately muffled. Their major disadvantages are size, weight, and cost. These disadvantages are only severe in vehicular and mobile power applications where the competition is open-cycle internal combustion engines (diesel, spark-ignition, or turbine). In underwater and space power applications where closed-cycle engines are a necessity, the use of Stirling engines shows more promise.

  1. The 1-kW solar Stirling experiment

    NASA Technical Reports Server (NTRS)

    Giandomenico, A.

    1981-01-01

    The objective of this experiment was to demonstrate electrical power generation using a small free-piston Stirling engine and linear alternator in conjunction with a parabolic solar collector. A test bed collector, formerly used at the JPL Table Mountain Observatory, was renovated and used to obtain practical experience and to determine test receiver performance. The collector was mounted on a two-axis tracker, with a cold water calorimeter mounted on the collector to measure its efficiency, while a separate, independently tracking radiometer was used to measure solar insolation. The solar receiver was designed to absorb energy from the collector, then transfer the resulting thermal energy to the Stirling engine. Successful testing of receiver/collector assembly yielded valuable inputs for design of the Stirling engine heater head.

  2. Thermoeconomic analysis of an irreversible Stirling heat pump cycle

    NASA Astrophysics Data System (ADS)

    Lucia, U.; Gervino, G.

    2006-03-01

    In this paper an analysis of the Stirling cycle in thermoeconomic terms is developed using the entropy generation. In the thermoeconomic optimization of an irreversible Stirling heat pump cycle the F function has been introduced to evaluate the optimum for the higher and lower sources temperature ratio in the cycle: this ratio represents the value which optimizes the cycle itself. The variation of the function F is proportional to the variation of the entropy generation, the maxima and minima of F has been evaluated in a previous paper without giving the physical foundation of the method. We investigate the groundwork of this approach: to study the upper and lower limits of F function allows to determine the cycle stability and the optimization conditions. The optimization consists in the best COP at the least cost. The principle of maximum variation for the entropy generation becomes the analytic foundation of the optimization method in the thermoeconomic analysis for an irreversible Stirling heat pump cycle.

  3. Thermoacoustically driven refrigerator with double thermoacoustic-Stirling cycles

    NASA Astrophysics Data System (ADS)

    Luo, Ercang; Dai, Wei; Zhang, Yong; Ling, Hong

    2006-02-01

    Recently, considerable research efforts have been made to search substitution technologies for chlorofluorocarbon-based vapor compression cycles due to the concern over environmental issues. This letter introduces a helium-based thermoacoustic refrigeration system, which is a thermoacoustic-Stirling refrigerator driven by a thermoacoustic-Stirling heat engine, for domestic refrigeration purpose. In the regenerators of both the refrigerator and the prime mover, helium gas experiences near to reversible high efficiency Stirling process. At the operating point with 3.0MPa mean pressure, 57.7Hz frequency, and 2.2kW heat input, the experimental cooler provides a lowest temperature of -64.4°C and 250W cooling power at -22.1°C. These results show good potential of the system to be an alternative in near future for domestic refrigeration with advantages of environment-friendliness, no moving parts, and heat driven mechanism.

  4. Technical status of the Dish/Stirling Joint Venture Program

    NASA Astrophysics Data System (ADS)

    Bean, John R.; Diver, Richard B.

    Initiated in 1991; the Dish/Stirling Joint Venture Program (DSJVP) is a 5-year, $17.2 million joint venture which is funded by Cummins Power Generation, Inc. (CPG) of Columbus, Indiana and the United States Department of Energy's (DOE) Solar Thermal and Biomass Power Division. Sandia National Laboratories administers and provides technical management for this contract on the DOE's behalf. In January, 1995; CPG advanced to Phase 3 of this three-phase contract. The objective of the DSJVP is to develop and commercialize a 7-kW. Dish/Stirling System for remote power markets by 1997. In this paper, the technical status of the major subsystems which comprise the CPG 7-kW(sub e) Dish/Stirling System is presented. These subsystems include the solar concentrator, heat pipe receiver, engine/alternator, power conditioning, and automatic controls.

  5. 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.

  6. 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.

  7. Technical status of the Dish/Stirling Joint Venture Program

    SciTech Connect

    Bean, J.R.; Diver, R.B.

    1995-06-01

    Initiated in 1991; the Dish/Stirling Joint Venture Program (DSJVP) is a 5-year, $17.2 million joint venture which is funded by Cummins Power Generation, Inc. (CPG) of Columbus, Indiana and the United States Department of Energy`s (DOE) Solar Thermal and Biomass Power Division. Sandia National Laboratories administers and provides technical management for this contract on the DOE`s behalf. In January, 1995; CPG advanced to Phase 3 of this three-phase contract. The objective of the DSJVP is to develop and commercialize a 7-kW. Dish/Stirling System for remote power markets by 1997. In this paper, the technical status of the major subsystems which comprise the CPG 7-kW{sub e} Dish/Stirling System is presented. These subsystems include the solar concentrator, heat pipe receiver, engine/alternator, power conditioning, and automatic controls.

  8. Overview of NASA supported Stirling thermodynamic loss research

    SciTech Connect

    Tew, R.C.; Geng, S.M.

    1994-09-01

    The National Aeronautics and Space Administration (NASA) is funding research to characterize Stirling machine thermodynamic losses. NASA`s primary goal is to improve Stirling design codes to support engine development for space and terrestrial power. However, much of the fundamental data is applicable to Stirling cooler and heat pump applications. The research results are reviewed. Much has been learned about oscillating-flow hydrodynamics, including laminar/turbulent transition, and tabulated data has been documented for further analysis. Now, with a better understanding of the oscillator-flow field, it is time to begin measuring the effects of oscillating flow and oscillating pressure level on heat transfer in heat exchanger flow passages and in cylinders. This critical phase of the work is just beginning.

  9. 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.

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  11. 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. PMID:16979679

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

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  13. A Self-Circulating Heat Exchanger for Use in Stirling and Thermoacoustic-Stirling Engines

    NASA Astrophysics Data System (ADS)

    Backhaus, Scott; Reid, Robert S.

    2005-02-01

    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.

  14. 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.

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

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.; Thieme, Lanny G.

    2004-01-01

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

  16. Free-piston Stirling technology for space power

    SciTech Connect

    Slaby, J.G.

    1994-09-01

    An overview is presented of the NASA Lewis Research Center free-piston Stirling engine activities directed toward space power. This work is being carried out under NASA`s new Civil Space Technology Initiative (CSTI). The overall goal of CSTI`s High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The Stirling cycle offers an attractive power conversion concept for space power needs. Discussed in this paper is the completion of the Space Power Demonstrator Engine (SPDE) testing - culminating in the generation of 25 kW of engine power from a dynamically-balanced opposed-piston Stirling engine at a temperature ratio of 2.0. Engine efficiency was approximately 22 percent. The SPDE recently has been divided into two separate single-cylinder engines, called Space Power Research Engines (SPRE), that now serve as test beds for the evaluation of key technology disciplines. These disciplines include hydrodynamic gas bearings, high-efficiency linear alternators, space qualified heat pipe heat exchangers, oscillating flow code validation, and engine loss understanding. The success of the SPDE at 650 K has resulted in a more ambitious Stirling endeavor - the design, fabrication, test and evaluation of a designed-for-space 25 kW per cylinder Stirling Space Engine (SSE). The SSE will operate at a hot metal temperature of 1050 K using superalloy materials. This design is a low temperature confirmation of the 1300 K design. It is the 1300 K free-piston Stirling power conversion system that is the ultimate goal; to be used in conjunction with the SP-100 reactor. The approach to this goal is in three temperature steps. However, this paper concentrates on the first two phases of this program - the 650 K SPDE and the 1050 K SSE.

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

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    2006-01-01

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

  18. Evaluation Of Different Power Conditioning Options For Stirling Generators

    NASA Astrophysics Data System (ADS)

    Garrigos, A.; Blanes, J. M.; Carrasco, J. A.; Maset, E.; Montalban, G.; Ejea, J.; Ferreres, A.; Sanchis, E.

    2011-10-01

    Free-piston Stirling engines are an interesting alternative for electrical power systems, especially in deep space missions where photovoltaic systems are not feasible. This kind of power generators contains two main parts, the Stirling machine and the linear alternator that converts the mechanical energy from the piston movement to electrical energy. Since the generated power is in AC form, several aspects should be assessed to use such kind of generators in a spacecraft power system: AC/DC topologies, power factor correction, power regulation techniques, integration into the power system, etc. This paper details power generator operation and explores different power conversion approaches.

  19. 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.

  20. Dish Stirling system integration and test progress report

    NASA Technical Reports Server (NTRS)

    Haglund, R. A.

    1982-01-01

    The integration and check-out of a complete Dish Solar Stirling Thermal Power System is described. The preliminary results of the tests conducted thus far are presented. The results are very encouraging and show promise of high performance and efficiency. The outstanding performance and durability of the 4-95 Stirling engine was the highlight of this 6 month integration and test activity. Exposure to severe heat, dust, sand and wind during the summer months and heavy rains, high winds, including sand storms and freezing cold in recent months did affected the engine or the receiver in any noticable manner.

  1. Overview of the GRC Stirling Convertor System Dynamic Model

    NASA Technical Reports Server (NTRS)

    Lewandowski, Edward J.; Regan, Timothy F.

    2004-01-01

    A Stirling Convertor System Dynamic Model has been developed at the Glenn Research Center for controls, dynamics, and systems development of free-piston convertor power systems. It models the Stirling cycle thermodynamics, heat flow, gas, mechanical, and mounting dynamics, the linear alternator, and the controller. The model's scope extends from the thermal energy input to thermal, mechanical dynamics, and electrical energy out, allowing one to study complex system interactions among subsystems. The model is a non-linear time-domain model containing sub-cycle dynamics, allowing it to simulate transient and dynamic phenomena that other models cannot. The model details and capability are discussed.

  2. The method of characteristics applied to Stirling engines

    SciTech Connect

    Taylor, D.R.

    1984-08-01

    Since Finkelstein first proposed a method of solving the equations of continuity, momentum and energy in a rigorous fashion, most analysts have concentrated on the nodal method for simulating Stirling engines. Organ has proposed a set of isothermal equations which may be solved by the method of characteristics. A solution method, by Benson, of the full set of equations has been in use for several years for the analysis of diesel engines. This paper discusses the application of the method of characteristics to the simulation of Stirling cycle machines.

  3. Dynamic simulation of kinematic Stirling engines: Coupled and decoupled analysis

    SciTech Connect

    Fischer, K.; Lemrani, H.; Stouffs, P.

    1995-12-31

    A coupled analysis modelling method of Stirling engines is presented. The main feature of this modelling method is the use of a software package combining the capabilities of a pre-/post-processor with a differential algebraic equations solver. As a result, modelling is merely a matter of linking appropriate objects from a model library and the outcoming tool is very flexible and powerful. Some simulation results are presented and compared with those obtained from a decoupled analysis. It clearly appears that the main imperfection of the model does not come from the modelling process itself but from their incomplete knowledge of the physics behind the Stirling engine operation.

  4. 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.

  5. Dish Stirling system integration and test progress report

    NASA Astrophysics Data System (ADS)

    Haglund, R. A.

    1982-07-01

    The integration and check-out of a complete Dish Solar Stirling Thermal Power System is described. The preliminary results of the tests conducted thus far are presented. The results are very encouraging and show promise of high performance and efficiency. The outstanding performance and durability of the 4-95 Stirling engine was the highlight of this 6 month integration and test activity. Exposure to severe heat, dust, sand and wind during the summer months and heavy rains, high winds, including sand storms and freezing cold in recent months did affected the engine or the receiver in any noticable manner.

  6. 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.

  7. Materials for a Stirling engine heater head

    NASA Technical Reports Server (NTRS)

    Noble, J. E.; Lehmann, G. A.; Emigh, S. G.

    1990-01-01

    Work done on the 25-kW advanced Stirling conversion system (ASCS) terrestrial solar program in establishing criteria and selecting materials for the engine heater head and heater tubes is described. Various mechanisms contributing to incompatibility between materials are identified and discussed. Large thermal gradients, coupled with requirements for long life (60,000 h at temperature) and a large number of heatup and cooldown cycles (20,000) drive the design from a structural standpoint. The pressurized cylinder is checked for creep rupture, localized yielding, reverse plasticity, creep and fatigue damage, and creep ratcheting, in addition to the basic requirements for bust and proof pressure. In general, creep rupture and creep and fatigue interaction are the dominant factors in the design. A wide range of materials for the heater head and tubes was evaluated. Factors involved in the assessment were strength and effect on engine efficiency, reliability, and cost. A preliminary selection of Inconel 713LC for the heater head is based on acceptable structural properties but driven mainly by low cost. The criteria for failure, the structural analysis, and the material characteristics with basis for selection are discussed.

  8. 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.

  9. 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.

  10. Study on heat transfer of heat exchangers in the Stirling engine - Performance of heat exchangers in the test Stirling engine

    NASA Astrophysics Data System (ADS)

    Kanzaka, Mitsuo; Iwabuchi, Makio

    1992-11-01

    The heat transfer performance of the actual heat exchangers obtained from the experimental results of the test Stirling engine is presented. The heater for the test engine has 120 heat transfer tubes that consist of a bare-tube part and a fin-tube part. These tubes are located around the combustion chamber and heated by the combustion gas. The cooler is the shell-and-tube-type heat exchanger and is chilled by water. It is shown that the experimental results of heat transfer performance of the heater and cooler of the test Stirling engine are in good agreement with the results calculated by the correlation proposed in our previous heat transfer study under the periodically reversing flow condition. Our correlation is thus confirmed to be applicable to the evaluation of the heat transfer coefficient and the thermal design of the heat exchangers in the Stirling engine.

  11. 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.

  12. Experimental Investigation on Regenerator Materials of Stirling-type Pulse-tube Refrigerator Working at 20 K

    NASA Astrophysics Data System (ADS)

    Zhou, Qiang; Chen, Liubiao; Pan, Changzhao; Zhou, Yuan; Wang, Junjie

    This paper will introduce our recent experimental results of cryogenic regenerator materials employed in Stirling-type one-stage pulse-tube refrigerator for the use at liquid hydrogen temperature. Thermal diffusion coefficient, according to which we choose the suitable regenerator materials, will prove to be a useful reference. We will also discuss the impact of resistance of sphere regenerator materials on the performance of the refrigerator and the method to improve it. Take an overall consideration, suitable-size Er3Ni will be applied as the regenerator materials at the cold head and we achieve a remarkable 14.7 K no-load temperature.

  13. 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.

  14. Structural Benchmark Testing for Stirling Converter Heater Heads

    NASA Astrophysics Data System (ADS)

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

    2007-01-01

    The National Aeronautics and Space Administration (NASA) has identified high efficiency Stirling technology for potential use on long duration Space Science missions such as Mars rovers, deep space missions, and lunar applications. For the long life times required, a structurally significant design limit for the Stirling convertor heater head is creep deformation induced even under relatively low stress levels at high material temperatures. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and much creep data is available for the proposed Inconel-718 (IN-718) and MarM-247 nickel-based superalloy materials of construction. However, very little experimental creep information is available that directly applies to the atypical thin walls, the specific microstructures, and the low stress levels. In addition, the geometry and loading conditions apply multiaxial stress states on the heater head components, far from the conditions of uniaxial testing. For these reasons, experimental benchmark testing is underway to aid in accurately assessing the durability of Stirling heater heads. The investigation supplements uniaxial creep testing with pneumatic testing of heater head test articles at elevated temperatures and with stress levels ranging from one to seven times design stresses. This paper presents experimental methods, results, post-test microstructural analyses, and conclusions for both accelerated and non-accelerated tests. The Stirling projects use the results to calibrate deterministic and probabilistic analytical creep models of the heater heads to predict their life times.

  15. Linear harmonic analysis of free-piston Stirling engines

    SciTech Connect

    Chen, N.C.J.; Griffin, F.P.

    1986-06-01

    The equations that govern the behavior of free-piston Stirling engines are nonlinear differential equations. Traditional solution methods have been time-stepping integrations that can be plagued by numerical instabilities and can use large amounts of computer time. Closed-form analytical solutions are possible if the working gas behaves isothermally or if the nonlinear terms in the governing equations are replaced with accurate approximations. An almost closed-form solution method, called the linear harmonic analysis (LHA), has been developed for free-piston Stirling engine applications by representing all of the periodic variables with harmonic functions. The solution method accounts for the important thermodynamic losses that are coupled together in free-piston engines, yet it is efficient enough for optimization studies. The LHA method was compared with a standard numerical integration method to verify its mathematical accuracy. The LHA and numerical predictions for a sample free-piston Stirling engine configuration differed by <5% for all important parameters. Sensitivity studies using the LHA method have also shown that the thermodynamic loss assumptions used in an analysis can have a significant impact on the predicted dynamic behavior of a free-piston Stirling engine.

  16. 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.

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

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.

    2006-01-01

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

  18. Assessment Of The Stirling Power Option for Space Science Applications

    NASA Technical Reports Server (NTRS)

    Schreiber, Jeffrey G.

    2000-01-01

    Free-piston Stirling technology efforts in the past typically were intended to address power needs in the multi-kilowatt range. The Stirling power option was attractive primarily because of the high conversion efficiency and potential for long life. In recent years, several technology efforts have focused on the free-piston Stirling power d convertor for space power applications, however the more recent efforts are intended to provide power at levels far below one kilowatt. Through a variety of projects funded by both NASA and DOE, the free-piston Stirling convertor technology has successfully demonstrated high efficiency and long life. Other areas of concern, such as control of multi-convertor systems, and vibration reduction have also been addressed. Efforts are being initiated to address issues such as electro-magnetic interference (EMI), radiation tolerance of organic materials, and the ability to operate through launch loads and survive with integrity. The status of the technology in these areas will be briefly discussed in this paper.

  19. Reliability Assessment Approach for Stirling Convertors and Generators

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore, M.

    2012-01-01

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

  1. Another Intuitive Approach to Stirling's Formula. Classroom Notes

    ERIC Educational Resources Information Center

    Osler, Thomas J.

    2004-01-01

    An intuitive derivation of Stirling's formula is presented, together with a modification that greatly improves its accuracy. The derivation is based on the closed form evaluation of the gamma function at an integer plus one-half. The modification is easily implemented on a hand-held calculator and often triples the number of significant digits…

  2. 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.

  3. Metallic phase change material thermal storage for Dish Stirling

    DOE PAGESBeta

    Andraka, C. E.; Kruizenga, A. M.; Hernandez-Sanchez, B. A.; Coker, E. N.

    2015-06-05

    Dish-Stirling systems provide high-efficiency solar-only electrical generation and currently hold the world record at 31.25%. This high efficiency results in a system with a high possibility of meeting the DOE SunShot goal of $0.06/kWh. However, current dish-Stirling systems do not incorporate thermal storage. For the next generation of non-intermittent and cost-competitive solar power plants, we propose adding a thermal energy storage system that combines latent (phase-change) energy transport and latent energy storage in order to match the isothermal input requirements of Stirling engines while also maximizing the exergetic efficiency of the entire system. This paper reports current findings in themore » area of selection, synthesis and evaluation of a suitable high performance metallic phase change material (PCM) as well as potential interactions with containment alloy materials. The metallic PCM's, while more expensive than salts, have been identified as having substantial performance advantages primarily due to high thermal conductivity, leading to high exergetic efficiency. Systems modeling has indicated, based on high dish Stirling system performance, an allowable cost of the PCM storage system that is substantially higher than SunShot goals for storage cost on tower systems. Several PCM's are identified with suitable melting temperature, cost, and performance.« less

  4. Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Technical Reports Server (NTRS)

    Anderson, William G.; Tarau, Calin

    2008-01-01

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

  5. The Stirling Engine: A Wave of the Future

    NASA Technical Reports Server (NTRS)

    1992-01-01

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

  6. 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.)

  7. 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.

  8. Operating single quantum emitters with a compact Stirling cryocooler

    SciTech Connect

    Schlehahn, A.; Krüger, L.; Gschrey, M.; Schulze, J.-H.; Rodt, S.; Strittmatter, A.; Heindel, T. Reitzenstein, S.

    2015-01-15

    The development of an easy-to-operate light source emitting single photons has become a major driving force in the emerging field of quantum information technology. Here, we report on the application of a compact and user-friendly Stirling cryocooler in the field of nanophotonics. The Stirling cryocooler is used to operate a single quantum emitter constituted of a semiconductor quantum dot (QD) at a base temperature below 30 K. Proper vibration decoupling of the cryocooler and its surrounding enables free-space micro-photoluminescence spectroscopy to identify and analyze different charge-carrier states within a single quantum dot. As an exemplary application in quantum optics, we perform a Hanbury-Brown and Twiss experiment demonstrating a strong suppression of multi-photon emission events with g{sup (2)}(0) < 0.04 from this Stirling-cooled single quantum emitter under continuous wave excitation. Comparative experiments performed on the same quantum dot in a liquid helium (LHe)-flow cryostat show almost identical values of g{sup (2)}(0) for both configurations at a given temperature. The results of this proof of principle experiment demonstrate that low-vibration Stirling cryocoolers that have so far been considered exotic to the field of nanophotonics are an attractive alternative to expensive closed-cycle cryostats or LHe-flow cryostats, which could pave the way for the development of high-quality table-top non-classical light sources.

  9. 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.

  10. Metallic phase change material thermal storage for Dish Stirling

    SciTech Connect

    Andraka, C. E.; Kruizenga, A. M.; Hernandez-Sanchez, B. A.; Coker, E. N.

    2015-06-05

    Dish-Stirling systems provide high-efficiency solar-only electrical generation and currently hold the world record at 31.25%. This high efficiency results in a system with a high possibility of meeting the DOE SunShot goal of $0.06/kWh. However, current dish-Stirling systems do not incorporate thermal storage. For the next generation of non-intermittent and cost-competitive solar power plants, we propose adding a thermal energy storage system that combines latent (phase-change) energy transport and latent energy storage in order to match the isothermal input requirements of Stirling engines while also maximizing the exergetic efficiency of the entire system. This paper reports current findings in the area of selection, synthesis and evaluation of a suitable high performance metallic phase change material (PCM) as well as potential interactions with containment alloy materials. The metallic PCM's, while more expensive than salts, have been identified as having substantial performance advantages primarily due to high thermal conductivity, leading to high exergetic efficiency. Systems modeling has indicated, based on high dish Stirling system performance, an allowable cost of the PCM storage system that is substantially higher than SunShot goals for storage cost on tower systems. Several PCM's are identified with suitable melting temperature, cost, and performance.

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

    NASA Technical Reports Server (NTRS)

    Brandhorst, Henry W.

    2007-01-01

    NASA has recently funded development of a 5 kW (or greater) free-piston Stirling conversion system for reactor power systems. A nominal 5 kW convertor allows two of these units to be dynamically balanced. A group of three dual-convertor combinations would yield the desired 30 kW. The status of this program will be presented. Goals include a specific power in excess of 140 W/kg at the convertor level, lifetime in excess of five years and AC output. The initial step is the design and development of a nominal 5 kW per cylinder Stirling convertor assembly (SCA) which will serve as a prototype of one or more SCAs that will make up the final 30 kW Stirling Convertor Power System. Assumed requirements for this new convertor for lunar fission power systems will be presented. The primary objective of this development effort will be to demonstrate a 5 kW SCA that can be tested to validate the viability of Stirling technology for space fission surface power systems.

  12. 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.

  13. Status of NASA's Stirling Space Power Converter Program

    NASA Technical Reports Server (NTRS)

    Dudenhoefer, James E.; Winter, Jerry M.

    1991-01-01

    An overview is presented of the NASA-Lewis Free-Piston Stirling Space Power Convertor Technology Program. The goal is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system power output and system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. Stirling experience in space and progress toward 1050 and 1300 K Stirling Space Power Converters is discussed. Fabrication is nearly completed for the 1050 K Component Test Power Converters (CTPC); results of motoring tests of cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing and predictive methodologies. An update is provided of progress in some of these technologies leading off with a discussion of free-piston Stirling experience in space.

  14. Stirling Analysis Comparison of Commercial vs. High-Order Methods

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    Recently, three-dimensional Stirling engine simulations have been accomplished utilizing commercial Computational Fluid Dynamics software. The validations reported can be somewhat inconclusive due to the lack of precise time accurate experimental results from engines, export control/ proprietary concerns, and the lack of variation in the methods utilized. The last issue may be addressed by solving the same flow problem with alternate methods. In this work, a comprehensive examination of the methods utilized in the commercial codes is compared with more recently developed high-order methods. Specifically, Lele's Compact scheme and Dyson s Ultra Hi-Fi method will be compared with the SIMPLE and PISO methods currently employed in CFD-ACE, FLUENT, CFX, and STAR-CD (all commercial codes which can in theory solve a three-dimensional Stirling model although sliding interfaces and their moving grids limit the effective time accuracy). We will initially look at one-dimensional flows since the current standard practice is to design and optimize Stirling engines with empirically corrected friction and heat transfer coefficients in an overall one-dimensional model. This comparison provides an idea of the range in which commercial CFD software for modeling Stirling engines may be expected to provide accurate results. In addition, this work provides a framework for improving current one-dimensional analysis codes.

  15. Status of NASA's Stirling Space Power Converter Program

    NASA Astrophysics Data System (ADS)

    Dudenhoefer, James E.; Winter, Jerry M.

    An overview is presented of the NASA-Lewis Free-Piston Stirling Space Power Convertor Technology Program. The goal is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system power output and system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. Stirling experience in space and progress toward 1050 and 1300 K Stirling Space Power Converters is discussed. Fabrication is nearly completed for the 1050 K Component Test Power Converters (CTPC); results of motoring tests of cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing and predictive methodologies. An update is provided of progress in some of these technologies leading off with a discussion of free-piston Stirling experience in space.

  16. Structural Benchmark Testing for Stirling Convertor Heater Heads

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    The National Aeronautics and Space Administration (NASA) has identified high efficiency Stirling technology for potential use on long duration Space Science missions such as Mars rovers, deep space missions, and lunar applications. For the long life times required, a structurally significant design limit for the Stirling convertor heater head is creep deformation induced even under relatively low stress levels at high material temperatures. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and much creep data is available for the proposed Inconel-718 (IN-718) and MarM-247 nickel-based superalloy materials of construction. However, very little experimental creep information is available that directly applies to the atypical thin walls, the specific microstructures, and the low stress levels. In addition, the geometry and loading conditions apply multiaxial stress states on the heater head components, far from the conditions of uniaxial testing. For these reasons, experimental benchmark testing is underway to aid in accurately assessing the durability of Stirling heater heads. The investigation supplements uniaxial creep testing with pneumatic testing of heater head test articles at elevated temperatures and with stress levels ranging from one to seven times design stresses. This paper presents experimental methods, results, post-test microstructural analyses, and conclusions for both accelerated and non-accelerated tests. The Stirling projects use the results to calibrate deterministic and probabilistic analytical creep models of the heater heads to predict their life times.

  17. Technology Development for a Stirling Radioisotope Power System

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  18. Stirling Analysis Comparison of Commercial Versus High-Order Methods

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    Recently, three-dimensional Stirling engine simulations have been accomplished utilizing commercial Computational Fluid Dynamics software. The validations reported can be somewhat inconclusive due to the lack of precise time accurate experimental results from engines, export control/proprietary concerns, and the lack of variation in the methods utilized. The last issue may be addressed by solving the same flow problem with alternate methods. In this work, a comprehensive examination of the methods utilized in the commercial codes is compared with more recently developed high-order methods. Specifically, Lele's compact scheme and Dyson's Ultra Hi-Fi method will be compared with the SIMPLE and PISO methods currently employed in CFD-ACE, FLUENT, CFX, and STAR-CD (all commercial codes which can in theory solve a three-dimensional Stirling model with sliding interfaces and their moving grids limit the effective time accuracy). We will initially look at one-dimensional flows since the current standard practice is to design and optimize Stirling engines with empirically corrected friction and heat transfer coefficients in an overall one-dimensional model. This comparison provides an idea of the range in which commercial CFD software for modeling Stirling engines may be expected to provide accurate results. In addition, this work provides a framework for improving current one-dimensional analysis codes.

  19. 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.

  20. Operating single quantum emitters with a compact Stirling cryocooler

    NASA Astrophysics Data System (ADS)

    Schlehahn, A.; Krüger, L.; Gschrey, M.; Schulze, J.-H.; Rodt, S.; Strittmatter, A.; Heindel, T.; Reitzenstein, S.

    2015-01-01

    The development of an easy-to-operate light source emitting single photons has become a major driving force in the emerging field of quantum information technology. Here, we report on the application of a compact and user-friendly Stirling cryocooler in the field of nanophotonics. The Stirling cryocooler is used to operate a single quantum emitter constituted of a semiconductor quantum dot (QD) at a base temperature below 30 K. Proper vibration decoupling of the cryocooler and its surrounding enables free-space micro-photoluminescence spectroscopy to identify and analyze different charge-carrier states within a single quantum dot. As an exemplary application in quantum optics, we perform a Hanbury-Brown and Twiss experiment demonstrating a strong suppression of multi-photon emission events with g(2)(0) < 0.04 from this Stirling-cooled single quantum emitter under continuous wave excitation. Comparative experiments performed on the same quantum dot in a liquid helium (LHe)-flow cryostat show almost identical values of g(2)(0) for both configurations at a given temperature. The results of this proof of principle experiment demonstrate that low-vibration Stirling cryocoolers that have so far been considered exotic to the field of nanophotonics are an attractive alternative to expensive closed-cycle cryostats or LHe-flow cryostats, which could pave the way for the development of high-quality table-top non-classical light sources.

  1. A reliability and mass perspective of SP-100 Stirling cycle lunar-base powerplant designs

    NASA Technical Reports Server (NTRS)

    Bloomfield, Harvey S.

    1991-01-01

    The purpose was to obtain reliability and mass perspectives on selection of space power system conceptual designs based on SP-100 reactor and Stirling cycle power-generation subsystems. The approach taken was to: (1) develop a criterion for an acceptable overall reliability risk as a function of the expected range of emerging technology subsystem unit reliabilities; (2) conduct reliability and mass analyses for a diverse matrix of 800-kWe lunar-base design configurations employing single and multiple powerplants with both full and partial subsystem redundancy combinations; and (3) derive reliability and mass perspectives on selection of conceptual design configurations that meet an acceptable reliability criterion with the minimum system mass increase relative to reference powerplant design. The developed perspectives provided valuable insight into the considerations required to identify and characterize high-reliability and low-mass lunar-base powerplant conceptual design.

  2. Regenerator optimization for Stirling cycle refrigeration II

    SciTech Connect

    Colgate, S.A.; Petschek, A.G.

    1994-07-01

    A cryogenic regenerator for a Stirling cycle is discussed using fractional loss or entropy gain as the criterion of performance. The gas losses are treated separately from heat storage medium losses. We argue that the optimum design corresponds to uniform channel flow with minimum turbulence where the gas velocity and channel width are optimized as a function of gas temperature. The maximization of heat transfer from the gas to the wall and the minimization of entropy production by friction leads to a gas flow velocity equal to sound speed times loss fraction, 1/{sigma}. This velocity and an axial thermal conductivity in the gas leads to a minimum channel width and characteristic length, L=T(dz/dT). A particular scaling of width, W{sup 2} = W{sub o}{sup 2}T{sup 1/2}, and length, L = L{sub o} T{sup {minus}1/2} leads to a design where longitudinal conduction decreases as T{sup 3/2} and the remaining two losses, transverse conduction and friction are equal and constant. The loss fraction, 1/{sigma}, must be made quite small, {approximately}(1/60) in order that the cumulative losses for a large temperature ratio like 300K to 4K, be small enough, like 20% to 40%. This is because half the entropy generated as a loss must be transported first to the cold end before returning to the hot end before being rejected. The dead volume ratio then determines the minimum frequency and with it and the pressure the necessary wall properties. The thermal properties of the channel wall must then accommodate this cyclic heat flow without substantially increasing the loss fraction. This generation of entropy in the walls is derived in terms of the wall heat capacity and thermal conductivity.

  3. Multiple Cylinder Free-Piston Stirling Machinery

    NASA Astrophysics Data System (ADS)

    Berchowitz, David M.; Kwon, Yong-Rak

    In order to improve the specific power of piston-cylinder type machinery, there is a point in capacity or power where an advantage accrues with increasing number of piston-cylinder assemblies. In the case of Stirling machinery where primary energy is transferred across the casing wall of the machine, this consideration is even more important. This is due primarily to the difference in scaling of basic power and the required heat transfer. Heat transfer is found to be progressively limited as the size of the machine increases. Multiple cylinder machines tend to preserve the surface area to volume ratio at more favorable levels. In addition, the spring effect of the working gas in the so-called alpha configuration is often sufficient to provide a high frequency resonance point that improves the specific power. There are a number of possible multiple cylinder configurations. The simplest is an opposed pair of piston-displacer machines (beta configuration). A three-cylinder machine requires stepped pistons to obtain proper volume phase relationships. Four to six cylinder configurations are also possible. A small demonstrator inline four cylinder alpha machine has been built to demonstrate both cooling operation and power generation. Data from this machine verifies theoretical expectations and is used to extrapolate the performance of future machines. Vibration levels are discussed and it is argued that some multiple cylinder machines have no linear component to the casing vibration but may have a nutating couple. Example applications are discussed ranging from general purpose coolers, computer cooling, exhaust heat power extraction and some high power engines.

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

    NASA Technical Reports Server (NTRS)

    Bents, D. J.

    1992-01-01

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

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

    SciTech Connect

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

    2009-03-16

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

  6. Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    NASA Astrophysics Data System (ADS)

    Anderson, William G.; Tarau, Calin

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Bents, D. J.

    1992-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

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

  9. Development of a Linear Stirling Model with Varying Heat Inputs

    NASA Technical Reports Server (NTRS)

    Regan, Timothy F.; Lewandowski, Edward J.

    2007-01-01

    The linear model of the Stirling system developed by NASA Glenn Research Center (GRC) has been extended to include a user-specified heat input. Previously developed linear models were limited to the Stirling convertor and electrical load. They represented the thermodynamic cycle with pressure factors that remained constant. The numerical values of the pressure factors were generated by linearizing GRC s non-linear System Dynamic Model (SDM) of the convertor at a chosen operating point. The pressure factors were fixed for that operating point, thus, the model lost accuracy if a transition to a different operating point were simulated. Although the previous linear model was used in developing controllers that manipulated current, voltage, and piston position, it could not be used in the development of control algorithms that regulated hot-end temperature. This basic model was extended to include the thermal dynamics associated with a hot-end temperature that varies over time in response to external changes as well as to changes in the Stirling cycle. The linear model described herein includes not only dynamics of the piston, displacer, gas, and electrical circuit, but also the transient effects of the heater head thermal inertia. The linear version algebraically couples two separate linear dynamic models, one model of the Stirling convertor and one model of the thermal system, through the pressure factors. The thermal system model includes heat flow of heat transfer fluid, insulation loss, and temperature drops from the heat source to the Stirling convertor expansion space. The linear model was compared to a nonlinear model, and performance was very similar. The resulting linear model can be implemented in a variety of computing environments, and is suitable for analysis with classical and state space controls analysis techniques.

  10. The FY1992 survey on commercialization of Stirling engine utilization equipment

    NASA Astrophysics Data System (ADS)

    1993-03-01

    Problems on commercialization of Stirling engine heat pumps (SEHP) and the solution are studied. The Stirling engine is a small and fixed engine having a 30-40% thermal efficiency and a 1-100 kW output. It is a closed recipro type external combustion engine with non-condensable gas like helium as working fluid. Its theoretical efficiency agrees with that of the Carnot's cycle. This is because the Stirling engine is often called a dream engine. However, the Stirling engine is legally restricted from a viewpoint of ensuring safety because high pressure gas as working fluid is sealed into the Stirling engine. It is feared that this point will be a condition that restricts spread/promotion of the equipment which uses the engine. Therefore, by guidance of MITI and support of organizations/enterprises concerned, a committee was started in 1992FY and studied the safety of the Stirling engine and the related legal systems.

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

    NASA Astrophysics Data System (ADS)

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

    2002-01-01

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

  12. Dish/Stirling systems: Overview of an emerging commercial solar thermal electric technology

    SciTech Connect

    Strachan, J.W.; Diver, R.B.; Estrada, C.

    1995-11-01

    Dish/Stirling is a solar thermal electric technology which couples parabolic, point-focusing solar collectors and heat engines which employ the Stirling thermodynamic cycle. Since the late 1970s, the development of Dish/Stirling systems intended for commercial use has been in progress in Germany, Japan, and the US. In the next several years it is expected that one or more commercial systems will enter the market place. This paper provides a general overview of this emerging technology, including: a description of the fundamental principles of operation of Dish/Stirling systems; a presentation of the major components of the systems (concentrator, receiver, engine/alternator, and controls); an overview of the actual systems under development around the world, with a discussion of some of the technical issues and challenges facing the Dish/Stirling developers. A brief discussion is also presented of potential applications for small Dish/Stirling systems in northern Mexico.

  13. The United Stirling P40 engine for solar dish concentrator application

    NASA Technical Reports Server (NTRS)

    Ortegren, L.; Sjostedt, L. E.

    1980-01-01

    The United Stirling P40 engine is a key component in a solar concentration based energy conversion system, to be demonstrated and tested during 1980-81. The inherent characteristics of modern Stirling engines is reviewed focusing on the baseline P40 double-acting engine. The extent of modifications required for the solar application is reviewed and performance data are predicted. Finally, the potential of an advanced solar Stirling engine is briefly considered.

  14. Overview of heat transfer and fluid flow problem areas encountered in Stirling engine modeling

    NASA Technical Reports Server (NTRS)

    Tew, Roy C., Jr.

    1988-01-01

    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.

  15. 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.

  16. 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.

  17. 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.

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

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Schifer, Nicholas A.

    2010-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Sullivan, T. J.

    1986-01-01

    In support of the U.S. 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 engine performance. The Lewis nodal-analysis Stirling engine computer simulation was used for this investigation. Results for the heater-bypass concept showed no significant improvement in the indicated thermal efficiency for the P-40 Stirling engine operating at full-power and part-power conditions. Optimizing the heater tube length produced a small increase in the indicated thermal efficiency with the heater-bypass concept.

  20. Inhomogeneity of fluid flow in Stirling engine regenerators

    SciTech Connect

    Jones, J.D. )

    1989-10-01

    The literature relating to inhomogeneity of flow regenerators is briefly reviewed. It is noted that, in contrast to other applications of regenerators, relatively little attention has been paid to the consequences of flow inhomogeneity for thermal regeneration in Stirling cycle machines. The construction of regenerator capsules for a large stationary Stirling engine is described. A test rig is developed to measure the gas velocity profile across the face of the packed regenerator capsules under steady flow conditions. Measured flow profiles for a number of different matrix materials and construction techniques are presented, and it is noted that stacked-mesh regenerator matrices tend to display marked inhomogeneities of flow. The consequences of flow inhomogeneity for flow friction and regenerator effectiveness are analyzed theoretically, and approximate formulae deduced. One method for reducing flow inhomogeneity in stacked-screen matrice

  1. Mathematical model of an air-filled alpha stirling refrigerator

    NASA Astrophysics Data System (ADS)

    McFarlane, Patrick; Semperlotti, Fabio; Sen, Mihir

    2013-10-01

    This work develops a mathematical model for an alpha Stirling refrigerator with air as the working fluid and will be useful in optimizing the mechanical design of these machines. Two pistons cyclically compress and expand air while moving sinusoidally in separate chambers connected by a regenerator, thus creating a temperature difference across the system. A complete non-linear mathematical model of the machine, including air thermodynamics, and heat transfer from the walls, as well as heat transfer and fluid resistance in the regenerator, is developed. Non-dimensional groups are derived, and the mathematical model is numerically solved. The heat transfer and work are found for both chambers, and the coefficient of performance of each chamber is calculated. Important design parameters are varied and their effect on refrigerator performance determined. This sensitivity analysis, which shows what the significant parameters are, is a useful tool for the design of practical Stirling refrigeration systems.

  2. A dish-Stirling solar-thermal power system

    NASA Technical Reports Server (NTRS)

    Pons, R. L.; Clark, T. B.

    1980-01-01

    This paper presents results of a preliminary design/economic study of a first-generation point focusing distributed receiver solar-thermal electric system optimized for application to industrial and small community power plants at power levels up to 10 MWe. Power conversion is provided by small Stirling cycle engines mounted at the focus of paraboloidal solar concentrators. The output of multiple power modules (concentrator, receiver, engine, and electric generator) is collected by means of a conventional electrical system and interfaced with a utility grid. Based on the United Stirling P-75 engine, a 1 MWe system employing mass-produced components (100,000 modules/year) could produce electricity at costs competitive with those projected for electricity generated by more conventional means, e.g. with fossil fuels.

  3. RE-1000 free-piston Stirling engine update

    NASA Technical Reports Server (NTRS)

    Schreiber, J. G.

    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.

  4. Pulse tube stirling machine with warm gas-driven displacer

    NASA Astrophysics Data System (ADS)

    Zhu, Shaowei; Nogawa, Masafumi

    2010-05-01

    A pulse tube type stirling machine with warm gas-driven displacer which has a displacer rod is discussed with numerical simulation when it is used as a cryogenic refrigerator, room temperature refrigerator and engine. It has both the advantages of gas-driven-stirling machine with high efficiency and simplicity and the advantages of pulse tube machine with no moving parts at low temperatures. A nodal analysis method that includes the linear motor and the displacer in the machine is introduced. Numerical results show that it has high potential to be used as the cryogenic refrigerator, room temperature refrigerator and engine. In this type of machine, there is an optimum phase angle between displacer and piston, and an optimum swept volume ratio of displacer over compressor for efficiency. The phase angle and swept volume ratio can be adjusted by the natural frequency of the displacer and the diameter of the displacer rod when it is used as a refrigerator.

  5. 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.

  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. 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.

  8. RE-1000 free-piston Stirling engine update

    SciTech Connect

    Schreiber, J.G.

    1985-01-01

    A free-piston Stirling engine has been under test at the NASA Lewis Research Center test facilities. 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 have been completed at Lewis. In addition, some data were recorded with alternate working fluids. A novel resonant balance system for the engine was also tested. This report presents some preliminary test results of the tests performed at the NASA Lewis facility 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.

  9. RE-1000 free-piston Stirling engine update

    NASA Astrophysics Data System (ADS)

    Schreiber, J. G.

    1985-05-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  11. 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.

  12. 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.

  13. 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.

  14. Gas-fired duplex free-piston Stirling refrigerator

    NASA Astrophysics Data System (ADS)

    Urieli, L.

    1984-03-01

    The duplex free-piston Stirling refrigerator is a potentially high efficiency, high reliability device which is ideally suited to the home appliance field, in particular as a gas-fired refrigerator. It has significant advantages over other equivalent devices including freedom from halogenated hydrocarbons, extremely low temperatures available at a high efficiency, integrated water heating, and simple burner system control. The design and development of a portable working demonstration gas-fired duplex Stirling refrigeration unit is described. A unique combination of computer aided development and experimental development was used, enabling a continued interaction between the theoretical analysis and practical testing and evaluation. A universal test rig was developed in order to separately test and evaluate major subunits, enabling a smooth system integration phase.

  15. Solar Stirling power generation - Systems analysis and preliminary tests

    NASA Technical Reports Server (NTRS)

    Selcuk, M. K.; Wu, Y.-C.; Moynihan, P. I.; Day, F. D., III

    1977-01-01

    The feasibility of an electric power generation system utilizing a sun-tracking parabolic concentrator and a Stirling engine/linear alternator is being evaluated. Performance predictions and cost analysis of a proposed large distributed system are discussed. Design details and preliminary test results are presented for a 9.5 ft diameter parabolic dish at the Jet Propulsion Laboratory (Caltech) Table Mountain Test Facility. Low temperature calorimetric measurements were conducted to evaluate the concentrator performance, and a helium flow system is being used to test the solar receiver at anticipated working fluid temperatures (up to 650 or 1200 C) to evaluate the receiver thermal performance. The receiver body is designed to adapt to a free-piston Stirling engine which powers a linear alternator assembly for direct electric power generation. During the next phase of the program, experiments with an engine and receiver integrated into the concentrator assembly are planned.

  16. 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.

  17. Sodium heat pipe use in solar Stirling power conversion systems

    NASA Technical Reports Server (NTRS)

    Zimmerman, W. F.; Divakaruni, S. M.; Won, Y. S.

    1980-01-01

    Sodium heat pipes were selected for use as a thermal transport method in a focus-mounted, distributed concentrator solar Stirling power conversion system intended to produce 15-20 kWe per unit. Heat pipes were used both to receive thermal power in the solar receiver and to transmit it to a secondary heat pipe containing both latent heat salt (for up to 1.25 hours of thermal storage) and the heat exchanger of the Stirling engine. Experimental tests were performed on five solar receiver heat pipes with various internal wicking configurations. The performance of the heat pipes at various power levels and operating attitudes was investigated at temperatures near 1550 F; the unidirectional heat transfer in these heat pipes was demonstrated in normal operating attitudes and particularly in the inverted position required during overnight stowage of the concentrator.

  18. Study of a coaxial thermoacoustic-Stirling cooler

    NASA Astrophysics Data System (ADS)

    Tijani, M. E. H.; Spoelstra, S.

    2008-01-01

    A coaxial thermoacoustic-Stirling cooler is built and performance measurements are performed. The cooler uses the acoustic power produced by a linear motor to pump heat through a regenerator from a cold heat exchanger to an ambient one. The cooler incorporates a compact acoustic network to create the traveling-wave phasing necessary for the operation in a Stirling cycle. The network has a coaxial geometry instead of the toroidal one usually used in such systems. The design, construction and performance measurements of the cooler are presented. A measured coefficient of performance relative to Carnot of 25% and a low temperature of -54 °C are achieved by the cooler. This efficiency surpasses the performance of the most efficient standing-wave cooler by almost a factor of two.

  19. Low-Mass Stirling Convertor Assembly Progress Update

    NASA Astrophysics Data System (ADS)

    Qiu, Songgang; Augenblick, John E.; Redinger, Darin L.

    2006-01-01

    Infinia is developing the next generation of space-ready Stirling Convertor Assemblies. Infinia has previously proposed a Low-Mass Stirling Convertor Assembly (SCA) design employing a flux-concentrating, moving-iron linear alternator. This paper describes further development of that proposed machine, including additional improvements and advancements. One significant change is a new, lighter-weight moving-magnet alternator design. Infinia has shown progress in the low mass design's development and testing: namely in the area of flexure spring rates, welding techniques on the flange, and a change to the alternator configuration. Progress has been made with the flat-top heater head design and its capabilities, as well. The changes described in this paper will significantly reduce the mass and increase the power density of the low-mass design.

  20. Study on Operating Characteristics of A House Hold Stirling Refrigerator

    NASA Astrophysics Data System (ADS)

    Otaka, Toshio; Sakamoto, Moriyoshi; Murakami, Kazuhiko; Ota, Masahiro

    A prototype Stirling cycle refrigerator employing helium as a working fluid has been investigated to see whether the freon free machine be a viable alternative for the current household refrigerator. The prototype is a kinematics drive, and β type Stirling cycle machine of 100W refrigeration. The performance was evaluated as a function of cooling head temperature, mean pressure, frequency, and cooling capacity. The prototype has achieved the targeted refrigeration of 100W, and the COP of 1.02 under the design operation condition; 16.7Hz frequency and 0.7MPa helium pressure. The performance data was compared with the predicted ones, which was obtained by the 3rd order computational method. It has been demonstrated that the performance is in a good agreement with the predicted in the whole range of operation condition.

  1. Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission

    NASA Astrophysics Data System (ADS)

    Schock, Alfred

    1994-07-01

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

  2. An overview of the Stirling engine heat pump program

    SciTech Connect

    Chen, F.C.

    1988-01-01

    The paper summarizes the recent developments in the Stirling engine-driven heat pump program activities sponsored by the Department of Energy (DOE) through Oak Ridge National Laboratory (ORNL). This technology has displayed its ability to meet the thermal performance objectives. Enhance technology options guided by value engineering principles are being pursued toward the development of an economically viable household engine-driven heat pump. 12 refs., 10 figs., 2 tabs.

  3. Split-Stirling Cryogenic Refrigerators For Detector Cooling

    NASA Astrophysics Data System (ADS)

    Lehrfeld, Daniel

    1983-08-01

    Unfortunately, for user and manufacturer both, the closed-cycle cryogenic cooler to date has deserved its reputation as the "weak-link" in IR systems. When the cooler requires service at intervals of a few hundred hours at best, the quality of the system it serves is unfairly diminished. This paper addresses technological advances in the art of Stirling-cycle coolers which will increasingly cause that image of military cryocoolers to change for the better. A family of split-cycle coolers designed for long MTBF and in the final stages of development is the focus of the discussion. Their technological evolution, from multi-year-MTBF satellite system Stirling coolers developed in the U.S., and the UA 7011 cooler (tne first all-linear, military, production cooler) developed in Holland, is explained. Three new machines are discussed. Both 1/4 watt and 1 watt (nominal capacity) at 80°K linear-resonant, free-dispLacer Stirling coolers designed for thousands of hours of service-free operation are examined. The third machine is an advanced 1/4 watt at 80°K Stirling cooler incorporating the same component improvements in its free-displacer while utilizing a crankshaft-driven compressor. All three are designed to be compatible with standard U.S. 60 element and 120/180 element detector/dewars. The technologies of linear-resonant compressor and free-displacer expanders as embodied in these machines is discussed in sufficient detail that the reasons for their superior performance will he clear.

  4. Heat-Transfer Head For Stirling-Cycle Machine

    NASA Technical Reports Server (NTRS)

    Emigh, Stuart G.; Lehmann, Gregory A.; Noble, Jack E.

    1995-01-01

    New common heat-transfer head for two cylinders of opposed-cylinder Stirling-cycle machine performs function formerly performed by two heat acceptors-one for each cycle. Simplifies structure of machine and increases efficiency of operation by reducing resistance to flow of working gas and/or increasing transfer of heat to or from working gas during flow between compression and expansion spaces of machine.

  5. 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.

  6. 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. PMID:19518394

  7. Supporting research and technology for automotive Stirling engine development

    NASA Technical Reports Server (NTRS)

    Tomazic, W. A.

    1980-01-01

    The technology advancement topics described are a part of the supporting research and technology (SRT) program conducted to support the major Stirling engine development program. This support focuses on developing alternatives or backups to the engine development in critical areas. These areas are materials, seals control, combustors and system analysis. Specific objectives and planned milestone schedules for future activities as now envisioned are described. These planned SRT activities are related to the timeline of the engine development program that they must support.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. 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.

  10. 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.

  11. A study of dynamic energy equations for Stirling cycle analysis

    NASA Technical Reports Server (NTRS)

    Larson, V. H.

    1983-01-01

    An analytical and computer study of the dynamic energy equations that describe the physical phenomena that occurs in a Stirling cycle engine. The basic problem is set up in terms of a set o hyperbolic partial differential equations. The characteristic lines are determined. The equations are then transformed to ordinary differential equations that are valid along characteristic lines. Computer programs to solve the differential equations and to plot pertinent factors are described.

  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. Split-Stirling-cycle displacer linear-electric drive

    NASA Technical Reports Server (NTRS)

    Ackermann, R. A.; Bhate, S. K.; Byrne, D. V.

    1983-01-01

    The retrofit of a 1/4-W split-Stirling cooler with a linear driven on the displacer was achieved and its performance characterized. The objective of this work was to demonstrate that a small linear motor could be designed to meet the existing envelope specifications of the cooler and that an electric linear drive on the displacer could improve the cooler's reliability and performance. The paper describes the characteristics of this motor and presents cooler test results.

  14. Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission

    SciTech Connect

    Schock, Alfred

    1993-10-01

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

  15. A Stirling engine analysis method based upon moving gas nodes

    NASA Technical Reports Server (NTRS)

    Martini, W. R.

    1986-01-01

    A Lagrangian nodal analysis method for Stirling engines (SEs) is described, validated, and applied to a conventional SE and an isothermalized SE (with fins in the hot and cold spaces). The analysis employs a constant-mass gas node (which moves with respect to the solid nodes during each time step) instead of the fixed gas nodes of Eulerian analysis. The isothermalized SE is found to have efficiency only slightly greater than that of a conventional SE.

  16. DOE/NASA Automotive Stirling Engine Project Overview 83

    NASA Technical Reports Server (NTRS)

    Beremand, D. G.

    1983-01-01

    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 percent 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. Previously announced in STAR as N83-27924

  17. Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission

    SciTech Connect

    Schock, Alfred

    2012-01-19

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

  18. FLIR systems submicro rotary stirling cycle IDCA for imaging systems

    NASA Astrophysics Data System (ADS)

    Uri, Bin-Nun

    2011-06-01

    The advantages of the common Rotary Stirling cycle coolers over the Split Stirling Linear are the overall size, light weight, low cooler input power and high efficiency. The main disadvantage has always been self induced vibration. Self induced vibration is a major consideration in the design of stabilized IR imaging systems/(GIMBALS) due to the effect it has on image quality i.e. Jitter. The "irregular shape" of the Rotary cooling engine attached to the payload and optics is also a problem in terms of the limits it has on optical system size. To address these issues, FLIR Systems Inc in Boston MA, developed a new rotary Stirling cycle cooling engine known as the FLIR Submicro Cooler. The Submicro is now in production and has been applied in a few products especially in FLIR"S smallest GIMBAL which measures 7.0 inch in spherical diameter. In this paper we discuss the improvements made in terms of IDCA implementation in stabilized imaging systems.

  19. FLIR systems submicro rotary stirling cycle IDCA for imaging systems

    NASA Astrophysics Data System (ADS)

    Bin-Nun, Uri

    2011-05-01

    The advantages of the common Rotary Stirling cycle coolers over the Split Stirling Linear are the overall size, light weight, low cooler input power and high efficiency. The main disadvantage has always been self induced vibration. Self induced vibration is a major consideration in the design of stabilized IR imaging systems/(GIMBALS) due to the effect it has on image quality i.e. Jitter. The "irregular shape" of the Rotary cooling engine attached to the payload and optics is also a problem in terms of the limits it has on optical system size. To address these issues, FLIR Systems Inc in Boston MA, developed a new rotary Stirling cycle cooling engine known as the FLIR Submicro Cooler. The Submicro is now in production and has been applied in a few products especially in FLIR"S smallest GIMBAL which measures 7.0 inch in spherical diameter. In this paper we discuss the improvements made in terms of IDCA implementation in stabilized imaging systems.

  20. Free-piston Stirling technology for space power

    NASA Technical Reports Server (NTRS)

    Slaby, Jack G.

    1989-01-01

    An overview is presented of the NASA Lewis Research Center free-piston Stirling engine activities directed toward space power. This work is being carried out under NASA's new Civil Space Technology Initiative (CSTI). The overall goal of CSTI's High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The Stirling cycle offers an attractive power conversion concept for space power needs. Discussed here is the completion of the Space Power Demonstrator Engine (SPDE) testing-culminating in the generation of 25 kW of engine power from a dynamically-balanced opposed-piston Stirling engine at a temperature ratio of 2.0. Engine efficiency was approximately 22 percent. The SPDE recently has been divided into two separate single-cylinder engines, called Space Power Research Engine (SPRE), that now serve as test beds for the evaluation of key technology disciplines. These disciplines include hydrodynamic gas bearings, high-efficiency linear alternators, space qualified heat pipe heat exchangers, oscillating flow code validation, and engine loss understanding.

  1. Structural Dynamics Testing of Advanced Stirling Convertor Components

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Williams, Zachary Douglas

    2013-01-01

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

  2. Power Conversion with a Stirling Cycle for Venus Surface Mission

    NASA Technical Reports Server (NTRS)

    Mellott, Ken

    2004-01-01

    The light-filtering characteristic of the dense, mostly-CO2 atmosphere of Venus, combined with the high atmospheric cloud cover, relegates the surface mission use of photovoltaic power systems and beckons for the independence and reliability of a nuclear-powered energy source. A multi-faceted Venus mission study was completed at NASA GRC in December of 2003 that resulted in the preliminary design of a helium- charged, kinematic Stirling converter, which is powered by nuclear, General Purpose Heat Source (GPHS) modules. The kinematic, Stirling power converter is configured to drive an electronics and sensor cooler in addition to a generator for electrical power. This paper briefly describes the design process and also describes and summarizes key features of the Stirling power converter preliminary design concept. With an estimated total efficiency of 23.4%, the power converter drives the electronics and sensor cooler, and also produces 100 watts of electricity. The converter rejects waste heat at a hot sink temperature of 500 C.

  3. Advanced Stirling Convertor Testing at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore

    2007-01-01

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

  4. 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.

  5. 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.

  6. 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.

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

    NASA Technical Reports Server (NTRS)

    Oriti, Salvatore M.; Cornell, Paggy A.

    2008-01-01

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

  8. 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.

  9. 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.

  10. 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.

  11. Lunar Surface Stirling Power Systems Using Isotope Heat Sources

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  12. Lunar Surface Stirling Power Systems Using Am-241

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  13. Dynamics and control of Stirling engines in a 15 kWe solar electric generation concept

    NASA Technical Reports Server (NTRS)

    Das, R. L.; Bahrami, K. A.

    1979-01-01

    This paper discusses the application of kinematic and free piston Stirling engines in a 15 kWe dish-electric approach for solar thermal electric generation. Initially, the principle of operation of Stirling engines in solar thermal electric generation is discussed. Then, under certain simplifying assumptions, mathematical models describing the dynamic operation of the kinematic and free piston Stirling engines are developed. It is found that the engine dynamics may be approximated by second order models. Control mechanisms for both types of Stirling engines are discussed. An approach based on the modulation of the working fluid mean pressure is presented. It is concluded that this approach offers a fast and effective means of control. The free piston Stirling engine, being a thermally driven mechanical oscillator, presents unique control requirements. These are discussed in this paper.

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

    NASA Technical Reports Server (NTRS)

    Furlong, Richard; Shaltens, Richard

    2000-01-01

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

  15. 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.

  16. Proceedings of the 25th Annual Stirling Physics Meeting 1999

    NASA Astrophysics Data System (ADS)

    McVey, Michael

    1999-09-01

    The 25th Annual Stirling Physics meeting took place on Thursday 20 May on a warm sunny day when the country setting of Stirling Campus could be seen at its best. A total of 225 participants from all sectors of physics education attended. There was an opportunity to view and discuss with exhibitors a wide range of state-of-the-art equipment and teaching materials both before and after the meeting. The theme of the meeting was `Maintaining Standards'. Gemmel Millar, Scottish Branch Secretary acting as Chairperson for the morning session and in anticipation of the first speaker, wondered if a new unit qualification, the `Planck' might be introduced. Half units would then be `Short Plancks' and how many Short Plancks must there be in a unit? Great stuff. Scottish Qualifications Authority Hugh McGill began with a brief history and description of the Scottish Qualifications Authority. Born on 1 April 1997 (a light frisson of amusement swept through the audience) it was a unification between SEB and SCOTVEC and has a range of responsibilities covering schools, further and higher education. It oversees Standard and Higher grades, HNC and HND and SVQs, and it has 500 full-time employees as well as some 13500 appointees who act as examiners, assessors and verifiers etc, without whom its remit could not be carried out. The committee structure of the Board was outlined, one each for national and higher national qualifications and a third for Scottish vocational qualifications. These will be served by a proposed 19 Advisory Groups. The Science Advisory Group will be the key body for advising SQA on strategic developments to ensure that qualifications meet the needs of both client groups and end users. A consultation paper `Added Value To Learning' was referred to, in which all qualifications available in Scotland are given parity of esteem on a rising 11-point scale. Mr McGill stated that standards would be best maintained by ensuring continuity in procedures developed over

  17. Large stationary Stirling engine. Volume 1. conceptual design of Stirling engines for stationary power-generation applications in the 500- to 3000-HP range. Final report

    SciTech Connect

    Not Available

    1980-08-01

    The Conceptual Design is described of Stirling Engines for Stationary Power Application in the 500 to 3000 hp range which was aimed at state-of-the-art stationary Stirling engines for a 1985 hardware demonstration, and an advanced engine design with identification of the supporting R and D efforts required. The main goals of this effort were to obtain reliable cost data for a stationary Stirling engine capable of meeting future needs for total energy/cogeneration systems and to establish a pragmatic and conservative base design for a first-generation hardware. In order to secure a competitive position for this engine in the marketplace, it was clearly recognized that a coal and waste product fired version had to be given primary consideration since a fuel oil or gas fired version would not be cost competitive with a diesel/gas engine. Therefore, the mating of the Stirling engine with an Atmospheric Fluidized Bed (AFB) was a main target.

  18. The 23rd Stirling Physics Meeting

    NASA Astrophysics Data System (ADS)

    1998-01-01

    derived from a standard Tesla coil with a high-Q secondary. This is capable of delivering around a million volts, which produce fantastic lightning flashes. A volunteer from the audience was invited to enter a huge Faraday Cage which was then subjected to these high voltage sparks! For a while the door of the cage jammed but eventually the victim emerged unscathed! This is, of course, not just an entertainment. The Gusto show is taken into schools and targeted at lower secondary pupils about to make their subject choices. The team also gives large scale physics demonstration lectures and could play to 10 000 children in a month. So physics is fun and physics is relevant to everyday life! Support for physics teachers Lesley Glasser chaired the afternoon session, which she opened by introducing the Institute's Education Officer. The Stirling Meeting would not be the same without the `commercial slot' presented again so ably by Catherine Wilson. Physics teachers are an endangered species and the Institute is determined to do whatever it can to support them. Plans are afoot to make sure the Schools Lectures are modified, if necessary, to take account of the educational differences in Scotland. The London-based `Physics in Perspective' course not only introduces sixth-formers to some of the frontiers of physics but gives enough free time for them to visit places of interest in the city - from the Science Museum to Soho. `So they associate physics with enjoyment!' Another Scottish Update Course is planned for teachers, and a brand new glossy booklet, sent free to all schools, will show pupils that choosing physics is a `Smart Move'. Finally the Institute has just started a major post-16 curriculum project which will include a variety of support materials to keep teachers abreast of continuing developments in physics. Each year, IoP Teacher of Physics Awards are given to `outstanding teachers of physics who inspire others to continue with and enjoy their physics'. Ann Jarvie

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

    NASA Astrophysics Data System (ADS)

    Schreiber, Jeffrey G.

    2001-02-01

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

  20. The 23rd Stirling Physics Meeting

    NASA Astrophysics Data System (ADS)

    1998-01-01

    derived from a standard Tesla coil with a high-Q secondary. This is capable of delivering around a million volts, which produce fantastic lightning flashes. A volunteer from the audience was invited to enter a huge Faraday Cage which was then subjected to these high voltage sparks! For a while the door of the cage jammed but eventually the victim emerged unscathed! This is, of course, not just an entertainment. The Gusto show is taken into schools and targeted at lower secondary pupils about to make their subject choices. The team also gives large scale physics demonstration lectures and could play to 10 000 children in a month. So physics is fun and physics is relevant to everyday life! Support for physics teachers Lesley Glasser chaired the afternoon session, which she opened by introducing the Institute's Education Officer. The Stirling Meeting would not be the same without the `commercial slot' presented again so ably by Catherine Wilson. Physics teachers are an endangered species and the Institute is determined to do whatever it can to support them. Plans are afoot to make sure the Schools Lectures are modified, if necessary, to take account of the educational differences in Scotland. The London-based `Physics in Perspective' course not only introduces sixth-formers to some of the frontiers of physics but gives enough free time for them to visit places of interest in the city - from the Science Museum to Soho. `So they associate physics with enjoyment!' Another Scottish Update Course is planned for teachers, and a brand new glossy booklet, sent free to all schools, will show pupils that choosing physics is a `Smart Move'. Finally the Institute has just started a major post-16 curriculum project which will include a variety of support materials to keep teachers abreast of continuing developments in physics. Each year, IoP Teacher of Physics Awards are given to `outstanding teachers of physics who inspire others to continue with and enjoy their physics'. Ann Jarvie