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Sample records for split stirling cycle

  1. Stability of split Stirling refrigerators

    NARCIS (Netherlands)

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

    2009-01-01

    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

  2. Theoretical modeling of a gas clearance phase regulation mechanism for a pneumatically-driven split-Stirling-cycle cryocooler

    Science.gov (United States)

    Zhang, Cun-quan; Zhong, Cheng

    2015-03-01

    The concept of a new type of pneumatically-driven split-Stirling-cycle cryocooler with clearance-phase-adjustor is proposed. In this implementation, the gap between the phase-adjusting part and the cylinder of the spring chamber is used, instead of dry friction acting on the pneumatically-driven rod to control motion damping of the displacer and to adjust the phase difference between the compression piston and displacer. It has the advantages of easy damping adjustment, low cost, and simplified manufacturing and assembly. A theoretical model has been established to simulate its dynamic performance. The linear compressor is modeled under adiabatic conditions, and the displacement of the compression piston is experimentally rectified. The working characteristics of the compressor motor and the principal losses of cooling, including regenerator inefficiency loss, solid conduction loss, shuttle loss, pump loss and radiation loss, are taken into account. The displacer motion was modeled as a single-degree-of-freedom (SDOF) forced system. A set of governing equations can be solved numerically to simulate the cooler's performance. The simulation is useful for understanding the physical processes occurring in the cooler and for predicting the cooler's performance.

  3. Stirling cycle engine

    Science.gov (United States)

    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.

  4. Basic dynamics of split Stirling refrigerators

    NARCIS (Netherlands)

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

    2008-01-01

    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 temp. at the cold end is an input

  5. Stirling Engine Cycle Efficiency

    OpenAIRE

    Naddaf, Nasrollah

    2012-01-01

    ABSTRACT This study strives to provide a clear explanation of the Stirling engine and its efficiency using new automation technology and the Lab View software. This heat engine was invented by Stirling, a Scottish in 1918. The engine’s working principles are based on the laws of thermodynamics and ability of volume expansion of ideal gases at different temperatures. Basically there are three types of Stirling engines: the gamma, beta and alpha models. The commissioner of the thesis ...

  6. Split-Stirling Cryogenic Refrigerators For Detector Cooling

    Science.gov (United States)

    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.

  7. Rotary Stirling-Cycle Engine And Generator

    Science.gov (United States)

    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.

  8. Idealization of The Real Stirling Cycle

    Directory of Open Access Journals (Sweden)

    Červenka Libor

    2016-12-01

    Full Text Available The paper presents a potential idealization of the real Stirling cycle. This idealization is performed by modifying the piston movement corresponding to the ideal Stirling cycle. The focus is on the cycle thermodynamics with respect to the indicated efficiency and indicated power. A detailed 1-D simulation model of a Stirling engine is used as a tool for this assessment. The model includes real non-zero volumes of heater, regenerator, cooler and connecting pipe. The model is created in the GT Power commercial simulation software.

  9. Alternative thermodynamic cycle for the Stirling machine

    Science.gov (United States)

    Romanelli, Alejandro

    2017-12-01

    We develop an alternative thermodynamic cycle for the Stirling machine, where the polytropic process plays a central role. Analytical expressions for pressure and temperatures of the working gas are obtained as a function of the volume and the parameter that characterizes the polytropic process. This approach achieves closer agreement with the experimental pressure-volume diagram and can be adapted to any type of Stirling engine.

  10. Optimization of an irreversible Stirling regenerative cycle

    International Nuclear Information System (INIS)

    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

  11. Multimodal tuned dynamic absorber for split Stirling linear cryocooler

    Science.gov (United States)

    Veprik, A.; Tuito, A.

    2017-02-01

    Forthcoming low size, weight, power and price split Stirling linear cryocoolers may rely on electro-dynamically driven single-piston compressors and pneumatically driven expanders interconnected by the configurable transfer line. For compactness, compressor and expander units may be placed in a side-by-side manner, thus producing tonal vibration export comprising force and moment components. In vibration sensitive applications, this may result in excessive angular line of sight jitter and translational defocusing affecting the image quality. The authors present Multimodal Tuned Dynamic Absorber (MTDA), having one translational and two tilting modes essentially tuned to the driving frequency. The dynamic reactions (force and moment) produced by such a MTDA are simultaneously counterbalancing force and moment vibration export produced by the cryocooler. The authors reveal the design details, the method of fine modal tuning and outcomes of numerical simulation on attainable performance.

  12. Development of a small Stirling cycle cooler for spaceflight applications

    International Nuclear Information System (INIS)

    Werrett, S.T.; Bradshaw, T.W.; Davey, G.; Delderfield, T.W.; Peskett, G.D.

    1986-01-01

    This paper describes the development, from a previously proven design approach, of a robust and simple Stirling cycle cooler with long life potential. The need for a closed cycle refrigerator for use in a spacecraft borne infra-red radiometer is explained. The refrigerator is to supply 1 watt of cooling at 80 K for less than 80 watts of input power, be able to survive the launch environment and subsequently run for 26000 hours. Clearance seals achieved with a spring suspension developed from earlier space proven mechanisms have led to the production of a linear split Stirling cycle machine with no apparent life limiting features. A servo control system, in conjunction with moving coil motors and LVDT position sensors, permits running of balanced pairs of mechanisms. The working fluid, helium at a pressure of 1.2 MPa, is contained within titanium bodies having gold O-ring seals. A vacuum bakeout procedure, based upon experience and outgassing trials, reduces residual contaminant release to acceptable levels. A prototype refrigerator has been subjected to a vibration test and has subsequently run for 6000 hours with no detectable change in performance

  13. Potential impacts of Brayton and Stirling cycle engines

    Science.gov (United States)

    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.

  14. Three-stage linear, split-Stirling cryocooler for 1 to 2K magnetic cold stage

    International Nuclear Information System (INIS)

    Longsworth, R.C.

    1993-08-01

    A long-life, linear, high efficiency 8K split Stirling cycle cryocooler was designed, built, and tested. The refrigerator is designed for cooling a 50 mW, 1.5K magnetic cold stage. Dual opposed piston compressors are driven by moving-coil linear motors. The three stage expander, although not completed, is also driven by a linear motor and is designed to produce 1 SW at 60K, 4W at 16K, and 1.2W at 8K. The cold regenerator employs a parallel gap construction for high efficiency. The key technology areas addressed include warm and cold flexible suspension bearings and a new cold regenerator geometry for high efficiency at 8K

  15. Analytical model for Stirling cycle machine design

    Energy Technology Data Exchange (ETDEWEB)

    Formosa, F. [Laboratoire SYMME, Universite de Savoie, BP 80439, 74944 Annecy le Vieux Cedex (France); Despesse, G. [Laboratoire Capteurs Actionneurs et Recuperation d' Energie, CEA-LETI-MINATEC, Grenoble (France)

    2010-10-15

    In order to study further the promising free piston Stirling engine architecture, there is a need of an analytical thermodynamic model which could be used in a dynamical analysis for preliminary design. To aim at more realistic values, the models have to take into account the heat losses and irreversibilities on the engine. An analytical model which encompasses the critical flaws of the regenerator and furthermore the heat exchangers effectivenesses has been developed. This model has been validated using the whole range of the experimental data available from the General Motor GPU-3 Stirling engine prototype. The effects of the technological and operating parameters on Stirling engine performance have been investigated. In addition to the regenerator influence, the effect of the cooler effectiveness is underlined. (author)

  16. Stirling cycle engines inner workings and design

    CERN Document Server

    Organ, Allan J

    2013-01-01

    Some 200 years after the original invention, internal design of a Stirling engine has come to be considered a specialist task, calling for extensive experience and for access to sophisticated computer modelling. The low parts-count of the type is negated by the complexity of the gas processes by which heat is converted to work. Design is perceived as problematic largely because those interactions are neither intuitively evident, nor capable of being made visible by laboratory experiment. There can be little doubt that the situation stands in the way of wider application of this elegant concep

  17. Liquid air fueled open–closed cycle Stirling engine

    International Nuclear Information System (INIS)

    Xu, Weiqing; Wang, Jia; Cai, Maolin; Shi, Yan

    2015-01-01

    Highlights: • Energy of liquid air is divided into cryogenic energy and expansion energy. • Open–closed cycle Stirling mechanism is employed to improve efficiency. • The Schmidt theory is modified to describe temperature variation in cold space. - Abstract: An unconventional Stirling engine is proposed and its theoretical analysis is performed. The engine belongs to a “cryogenic heat engine” that is fueled by cryogenic medium. Conventional “cryogenic heat engine” employs liquid air as pressure source, but disregards its heat-absorbing ability. Therefore, its efficiency can only be improved by increasing vapor pressure, accordingly increasing the demand on pressure resistance and sealing. In the proposed engine, the added Stirling mechanism helps achieve its high efficiency and simplicity by utilizing the heat-absorbing ability of liquid air. On one hand, based on Stirling mechanism, gas in the hot space absorbs heat from atmosphere when expanding; gas in the cold space is cooled down by liquid air when compressed. Taking atmosphere as heat source and liquid air as heat sink, a closed Stirling cycle is formed. On the other hand, an exhaust port is set in the hot space. When expanding in the hot space, the vaporized gas is discharged through the exhaust port. Thus, an open cycle is established. To model and analyze the system, the Schmidt theory is modified to describe temperature variation in the cold space, and irreversible characteristic of regenerator is incorporated in the thermodynamic model. The results obtained from the model show that under the same working pressure, the efficiency of the proposed engine is potentially higher than that of conventional ones and to achieve the same efficiency, the working pressure could be lower with the new mechanism. Its efficiency could be improved by reducing temperature difference between the regenerator and the cold/hot space, increasing the swept volume ratio, decreasing the liquid–gas ratio. To keep

  18. Development of High Capacity Split Stirling Cryocooler for HTS

    Science.gov (United States)

    Yumoto, Kenta; Nakano, Kyosuke; Hiratsuka, Yoshikatsu

    Sumitomo Heavy Industries, Ltd. (SHI) developed a high-power Stirling-type pulse tube cryocooler for cooling high-temperature superconductor (HTS) devices, such as superconductor motors, superconducting magnetic energy storage (SMES), and fault current limiters. The experimental results of a prototype pulse tube cryocooler were reported in September 2013. For a U-type expander, the cooling capacity was 151 W at 70 K with a compressor input power of 4 kW. Correspondingly, the coefficient of performance (COP) was about 0.038. However, the efficiency of the cryocooler is required to be COP > 0.1 and it was found that, theoretically, it is difficult to further improve the efficiency of a pulse tube cryocooler because the workflow generated at the hot end of the pulse tube cannot be recovered. Therefore, it was decided to change the expander to a free-piston type from a pulse tube type. A prototype was developed and preliminary experiments were conducted. A cooling capacity of 120 W at 70 K with a compressor input power of 2.15 kW with corresponding COP of 0.056, was obtained. The detailed results are reported in this paper.

  19. Stirling Refrigerator

    Science.gov (United States)

    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.

  20. General performance characteristics of an irreversible ferromagnetic Stirling refrigeration cycle

    International Nuclear Information System (INIS)

    Lin, G.; Tegus, O.; Zhang, L.; Brueck, E.

    2004-01-01

    A new magnetic-refrigeration-cycle model using ferromagnetic materials as a cyclic working substance is set up, in which finite-rate heat transfer, heat leak and regeneration time are taken into account. On the basis of the thermodynamic properties of a ferromagnetic material, the general performance characteristics of the ferromagnetic Stirling refrigeration cycle are investigated and the effects of some key irreversibilities on the performance of the cycle are revealed. By using the optimal-control theory, the optimal relation between the coefficient of performance and the cooling rate is derived and some important performance bounds, e.g., the maximum cooling rate, the maximum coefficient of performance, are determined. Moreover, the optimal operating regions for cooling rate, coefficient of performance and the optimal operating temperatures of a cyclic working substance in the two heat-transfer processes are obtained. Furthermore, the influences of magnetization and magnetic field on the performance characteristics of the cycle are discussed. The results obtained here have general significance and can be deduced to the related ones of the Stirling refrigeration cycle using paramagnetic salt as a cyclic working substance

  1. The design of a small linear-resonant, split Stirling cryogenic refrigerator compressor

    Science.gov (United States)

    Ackermann, R. A.

    1985-01-01

    The development of a small linear-resonant compressor for use in a 1/4-watt, 78K, split Stirling cryogenic refrigerator is discussed. The compressor contains the following special features: (1) a permanent-magnet linear motor; (2) resonant dynamics; (3) dynamic balancing; and (4) a close-clearance seal between the compressor piston and cylinder. This paper describes the design of the compressor, and presents component test data and system test data for the compressor driving a 1/4-watt expander.

  2. Exergy optimization for a novel combination of organic Rankine cycles, Stirling cycle and direct expander turbines

    Science.gov (United States)

    Moghimi, Mahdi; Khosravian, Mohammadreza

    2018-06-01

    In this paper, a novel combination of organic Rankine cycles (ORCs), Stirling cycle and direct expander turbines is modeled and optimized using the genetic algorithm. The Exergy efficiency is considered as an objective function in the genetic algorithm. High efficiency is the main advantage of Stirling cycle, however, it needs nearly isothermal compressor and turbine. Therefore, an argon ORC and a R14 ORC are placed before and after the Striling cycle along with two expander turbines at the end of the line. Each component and cycle of the proposed plant in this article is verified by the previous works available in the literature and good agreement is achieved. The obtained results reveal that 27.98%, 20.86% and 12.90% of the total cold exergy are used by argon ORC, Stirling cycle and R14 ORC, respectively. Therefore, utilization of the Stirling cycle is a good idea for the LNG line cold exergy. The maximum exergy destruction occurs in the heat exchanger after the argon ORC (85.786 kJ/s per one kg/s LNG) due to the wasted cold exergy, which can be used for air conditioning systems in the plant. Finally, it would be shown that the maximum efficiency of the proposed plant is 54.25% and the maximum output power is 355.72 kW.

  3. Exergy optimization for a novel combination of organic Rankine cycles, Stirling cycle and direct expander turbines

    Science.gov (United States)

    Moghimi, Mahdi; Khosravian, Mohammadreza

    2018-01-01

    In this paper, a novel combination of organic Rankine cycles (ORCs), Stirling cycle and direct expander turbines is modeled and optimized using the genetic algorithm. The Exergy efficiency is considered as an objective function in the genetic algorithm. High efficiency is the main advantage of Stirling cycle, however, it needs nearly isothermal compressor and turbine. Therefore, an argon ORC and a R14 ORC are placed before and after the Striling cycle along with two expander turbines at the end of the line. Each component and cycle of the proposed plant in this article is verified by the previous works available in the literature and good agreement is achieved. The obtained results reveal that 27.98%, 20.86% and 12.90% of the total cold exergy are used by argon ORC, Stirling cycle and R14 ORC, respectively. Therefore, utilization of the Stirling cycle is a good idea for the LNG line cold exergy. The maximum exergy destruction occurs in the heat exchanger after the argon ORC (85.786 kJ/s per one kg/s LNG) due to the wasted cold exergy, which can be used for air conditioning systems in the plant. Finally, it would be shown that the maximum efficiency of the proposed plant is 54.25% and the maximum output power is 355.72 kW.

  4. Development of a small Stirling-cycle cooler for spaceflight applications

    Energy Technology Data Exchange (ETDEWEB)

    Werrett, S.T.; Peskett, G.D.; Davey, G.; Bradshaw, T.W.; Delderfield, J.

    1985-01-01

    The paper describes the development, from a previously proven design approach, of a robust and simple Stirling-cycle cooler with long-life potential. The need for a closed-cycle refrigerator for use in a spacecraft borne infrared radiometer is explained. The refrigerator is to supply 1 watt of cooling at 80 K for less than 80 watts of input power, be able to survive the launch environment and subsequently run for 26000 hours. Clearance seals achieved with a spring suspension developed from earlier space-proven mechanisms have led to the production of a linear split Stirling-cycle machine with no apparent life limiting features. A servo-control system, in conjunction with moving coil motors and LVDT position sensors, permits running of balanced pairs of mechanisms. The working fluid, helium at a pressure of 1.2 MPa, is contained within titanium bodies having gold O-ring seals. A vacuum-bakeout procedure, based upon experience and outgassing trials, reduces residual contaminant release to acceptable levels. A prototype refrigerator was subjected to a vibration test and has subsequently run for 6000 hours with no detectable change in performance.

  5. Controlled rate cooling of fungi using a stirling cycle freezer.

    Science.gov (United States)

    Ryan, Matthew J; Kasulyte-Creasey, Daiva; Kermode, Anthony; San, Shwe Phue; Buddie, Alan G

    2014-01-01

    The use of a Stirling cycle freezer for cryopreservation is considered to have significant advantages over traditional methodologies including N2 free operation, application of low cooling rates, reduction of sample contamination risks and control of ice nucleation. The study assesses the suitability of an 'N2-free' Stirling Cycle controlled rate freezer for fungi cryopreservation. In total, 77 fungi representing a broad taxonomic coverage were cooled using the N2 free cooler following a cooling rate of -1 degrees C min(-1). Of these, 15 strains were also cryopreserved using a traditional 'N2 gas chamber' controlled rate cooler and a comparison of culture morphology and genomic stability against non-cryopreserved starter cultures was undertaken. In total of 75 fungi survived cryopreservation, only a recalcitrant Basidiomycete and filamentous Chromist failed to survive. No changes were detected in genomic profile after preservation, suggesting that genomic function is not adversely compromised as a result of using 'N2 free' cooling. The results demonstrate the potential of 'N2-free' cooling for the routine cryopreservation of fungi in Biological Resource Centres.

  6. Helioseismic Solar Cycle Changes and Splitting Coefficients

    Indian Academy of Sciences (India)

    tribpo

    Abstract. Using the GONG data for a period over four years, we have studied the variation of frequencies and splitting coefficients with solar cycle. Frequencies and even-order coefficients are found to change signi- ficantly with rising phase of the solar cycle. We also find temporal varia- tions in the rotation rate near the solar ...

  7. 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

    International Nuclear Information System (INIS)

    Anon.

    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

  8. Evaluation of the maximized power of a regenerative endoreversible Stirling cycle using the thermodynamic analysis

    International Nuclear Information System (INIS)

    Ahmadi, Mohammad H.; Mohammadi, Amir H.; Dehghani, Saeed

    2013-01-01

    Highlights: • The optimal power of an endoreversible Stirling cycle is investigated. • In the endoreversible cycle, external heat transfer processes are considered irreversible. • Optimal temperature of the heat source leading to a maximum power for the cycle is detained. • Effect of design parameters on the power and its corresponding thermal efficiency is studied. - Abstract: In this communication, the optimal power of an endoreversible Stirling cycle with perfect regeneration is investigated. In the endoreversible cycle, external heat transfer processes are irreversible. Optimal temperature of the heat source leading to a maximum power for the cycle is detained. Moreover, effect of design parameters of the Stirling engine on the maximized power of the engine and its corresponding thermal efficiency is studied

  9. Using cryogenic exergy of liquefied natural gas for electricity production with the Stirling cycle

    International Nuclear Information System (INIS)

    Dong, Hui; Zhao, Liang; Zhang, Songyuan; Wang, Aihua; Cai, Jiuju

    2013-01-01

    Cryogenic generation is one of the most important ways to utilize cold energy during LNG (liquefied natural gas) regasification. This paper fundamentally investigates LNG cryogenic generation with the Stirling cycle method based on previous studies. A basic process of LNG cryogenic generation with the Stirling cycle was presented initially with seawater and LNG as heat source and heat sink. And its thermodynamic analysis was performed to verify the theoretical feasibility of the Stirling cycle method. The generating capacity, the exergy efficiency and the cold energy utilization efficiency of the basic process were also calculated. Subsequently, the influences of evaporation pressure on net work, equipment performance and comprehensive efficiency of cold energy utilization were discussed and the effect of LNG mass flow as well as the ambient temperature was also studied. Finally an improved process of LNG cryogenic generation with Stirling cycle method combined with an air liquefaction process is proposed as feasibility in improvements of the basic process. - Highlights: • We propose a basic process of LNG cryogenic generation with the Stirling cycle. • Seawater and LNG were applied as heat source and heat sink of the basic process. • The max generating capacity of the basic process is 51 kWh/tLNG. • The max cold energy utilization efficiency of the basic process is 0.56. • We also discussed some feasibilities of optimization of the basic cycle

  10. Novel concept for driving the linear compressor of a micro-miniature split Stirling cryogenic cooler

    Science.gov (United States)

    Maron, V.; Veprik, A.; Finkelstein, L.; Vilenchik, H.; Ziv, I.; Pundak, N.

    2009-05-01

    New methods of carrying out homeland security and antiterrorist operations call for the development of a new generation of mechanically cooled, portable, battery powered infrared imagers, relying on micro-miniature Stirling cryogenic coolers of rotary or linear types. Since split Stirling linearly driven micro-miniature cryogenic coolers have inherently longer life spans, low vibration export and better aural stealth as compared to their rotary driven rivals, they are more suitable for the above applications. The performance of such cryogenic coolers depends strongly on the efficacy of their electronic drivers. In a traditional approach, the PWM power electronics produce the fixed frequency tonal driving voltage/current, the magnitude of which is modulated via a PID control law so as to maintain the desired focal plane array temperature. The disadvantage of such drivers is that they draw high ripple current from the system's power bus. This results in the need for an oversized DC power supply (battery packs) and power electronic components, low efficiency due to excessive conductive losses and high residual electromagnetic interference which in turn degrades the performance of other systems connected to the same power bus. Without either an active line filter or large and heavy passive filtering, other electronics can not be powered from the same power bus, unless they incorporate heavy filtering at their inputs. The authors present the results of a feasibility study towards developing a novel "pumping" driver consuming essentially constant instant battery power/current without making use of an active or passive filter. In the tested setup, the driver relies on a bidirectional controllable bridge, invertible with the driving frequency, and a fast regulated DC/DC converter which maintains a constant level of current consumed from the DC power supply and thus operates in input current control mode. From the experimental results, the steady-state power consumed by the

  11. Computation techniques and computer programs to analyze Stirling cycle engines using characteristic dynamic energy equations

    Science.gov (United States)

    Larson, V. H.

    1982-01-01

    The basic equations that are used to describe the physical phenomena in a Stirling cycle engine are the general energy equations and equations for the conservation of mass and conversion of momentum. These equations, together with the equation of state, an analytical expression for the gas velocity, and an equation for mesh temperature are used in this computer study of Stirling cycle characteristics. The partial differential equations describing the physical phenomena that occurs in a Stirling cycle engine are of the hyperbolic type. The hyperbolic equations have real characteristic lines. By utilizing appropriate points along these curved lines the partial differential equations can be reduced to ordinary differential equations. These equations are solved numerically using a fourth-fifth order Runge-Kutta integration technique.

  12. Optimization of Stirling and Ericsson cycles by solar radiation

    Science.gov (United States)

    Badescu, V.

    This paper considers a model consisting of a source of radiation (the sun) and two energy converters. The first converter (the absorber) transforms the solar radiation into heat while the second one (which is a Stirling or Ericsson engine) uses heat to produce mechanical work. Polarization coefficients were introduced to characterize the radiation emitted by two components of the system (the sun and the first converter). The maximum conversion efficiency of solar radiation into work was studied.

  13. Comparison of the Net Work Output between Stirling and Ericsson Cycles

    Directory of Open Access Journals (Sweden)

    Rui F. Costa

    2018-03-01

    Full Text Available In this paper, we compare Stirling and Ericsson cycles to determine which engine produces greater net work output for various situations. Both cycles are for external heat engines that utilize regenerators, where the difference is the nature of the regeneration process, which is constant volume for Stirling and constant pressure for Ericsson. This difference alters the performance characteristics of the two engines drastically, and our comparison reveals which one produces greater net work output based on the thermodynamic parameters. The net work output equations are derived and analysed for three different scenarios: (i equal mass and temperature limits; (ii equal mass and pressure or volume; and (iii equal temperature and pressure or volume limits. The comparison is performed by calculating when both cycles produce equal net work output and then analysing which one produces greater net work output based on how the parameters are varied. In general, the results demonstrate that Stirling engines produce more net work output at higher pressures and lower volumes, and Ericsson engines produce more net work output at lower pressures and higher volumes. For certain scenarios, threshold values are calculated to illustrate precisely when one cycle produces more net work output than the other. This paper can be used to inform the design of the engines and to determine when a Stirling or Ericsson engine should be selected for a particular application.

  14. Performance of V-type Stirling-cycle refrigerator for different working fluids

    Energy Technology Data Exchange (ETDEWEB)

    Tekin, Yusuf; Ataer, Omer Ercan [Erciyes University, Engineering Faculty, Mechanical Engineering Department, Melikgazi, 38 039 Kayseri (Turkey)

    2010-01-15

    The thermodynamic analysis of a V-type Stirling-cycle Refrigerator (VSR) is performed for air, hydrogen and helium as the working fluid and the performance of the VSR is investigated. The V-type Stirling-cycle refrigerator consists of expansion and compression spaces, cooler, heater and regenerator, and it is assumed that the control volumes are subjected to a periodic mass flow. The basic equations of the VSR are derived for per unit crank angle, so time does not appear in the equations. A computer program is prepared in FORTRAN, and the basic equations are solved iteratively. The mass, temperature and density of working fluid in each control volume are calculated for different charge pressures, engine speeds, and for fixed heater and cooler surface temperatures. The work, instantaneous pressure and the COP of the VSR are calculated. The results are obtained for different working fluids, and given by diagrams. (author)

  15. Electromagnetic compatibility characterization of a BAe Stirling-cycle cryocooler for space application

    Science.gov (United States)

    Johnson, Dean L.; Ross, Ronald G., Jr.

    1991-01-01

    This paper describes the electromagnetic compatibility (EMC) measurements of an 80-K Stirling-cycle cooler. The measurements, performed in the JPL EMC test facility, include dc magnetic field characterization, radiated magnetic and electric field emissions, and conducted emissions on the internal lines between the cooler electronics and the cooler. The measurements conform to both the MILSTD-461C specifications as well as to the specifications for the NASA Earth Observing System.

  16. Liquid air fueled open-closed cycle Stirling engine and its exergy analysis

    International Nuclear Information System (INIS)

    Wang, Jia; Xu, Weiqing; Ding, Shuiting; Shi, Yan; Cai, Maolin; Rehman, Ali

    2015-01-01

    An unconventional Stirling engine is proposed and its theoretical analysis is performed. The engine belongs to a “cryogenic heat engine” that is fueled by cryogenic medium. Conventional “cryogenic heat engine” employs liquid air as a pressure source, but disregards its heat-absorbing ability. Therefore, its efficiency can only be improved by increasing vapor pressure, accordingly increasing the demand on pressure resistance and sealing. In the proposed engine, a closed cycle structure of Stirling engine is added to combine with the open cycle structure of a conventional cryogenic heat engine to achieve high efficiency and simplicity by utilizing the heat-absorbing ability of liquid air. Besides, the theoretical analysis of the proposed engine is performed. The Schmidt theory is modified to model temperature variation in the cold space of the engine, and irreversible characteristic of regenerator is incorporated in the thermodynamic model. The modeling results show that under the same working pressure, the efficiency of the proposed engine is potentially higher than that of conventional ones and to achieve the same efficiency, the working pressure could be lower with the new mechanism. Composition of exergy loss in the proposed engine is analyzed. - Highlights: • Cryogenic energy is better exploited by the open-closed cycle Stirling mechanism. • The Schmidt theory is modified to model temperature variation. • Irreversible characteristics are incorporated in the thermodynamic model. • Composition of exergy loss in proposed engine is analyzed.

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

    Science.gov (United States)

    Luo, Ercang

    2012-06-01

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

  18. Comparative simulation of Stirling and Sibling cycle cryocoolers with two codes

    International Nuclear Information System (INIS)

    Mitchell, M.P.; Wilson, K.J.; Bauwens, L.

    1989-01-01

    The authors present a comparative analysis of Stirling and Sibling Cycle cryocoolers conducted with two different computer simulation codes. One code (CRYOWEISS) performs an initial analysis on the assumption of isothermal conditions in the machines and adjusts that result with decoupled loss calculations. The other code (MS*2) models fluid flows and heat transfers more realistically but ignores significant loss mechanisms, including flow friction and heat conduction through the metal of the machines. Surprisingly, MS*2 is less optimistic about performance of all machines even though it ignores losses that are modelled by CRYOWEISS. Comparison between constant-bore Stirling and Sibling machines shows that their performance is generally comparable over a range of temperatures, pressures and operating speeds. No machine was consistently superior or inferior according to both codes over the whole range of conditions studied

  19. Performance analysis of irreversible quantum Stirling cryogenic refrigeration cycles and their parametric optimum criteria

    International Nuclear Information System (INIS)

    Lin Bihong; Chen Jincan

    2006-01-01

    The influence of both the quantum degeneracy and the finite-rate heat transfer between the working substance and the heat reservoirs on the optimal performance of an irreversible Stirling cryogenic refrigeration cycle using an ideal Fermi or Bose gas as the working substance is investigated, based on the theory of statistical mechanics and thermodynamic properties of ideal quantum gases. The inherent regeneration losses of the cycle are analysed. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the cycle is optimized for a given power input. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal regions of the coefficient of performance and power input are determined. In particular, the optimal performance of the cycle in the strong and weak gas degeneracy cases and the high temperature limit are discussed in detail. The analytic expressions of some optimized parameters are derived. Some optimum criteria are given. The distinctions and connections between the Stirling refrigeration cycles working with the ideal quantum and classical gases are revealed

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

    Kubo, I.

    1987-01-01

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

  2. Stirling Engine Gets Revisited

    Science.gov (United States)

    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…

  3. Thermodynamic analysis of a gas turbine cycle equipped with a non-ideal adiabatic model for a double acting Stirling engine

    International Nuclear Information System (INIS)

    Korlu, Mahmood; Pirkandi, Jamasb; Maroufi, Arman

    2017-01-01

    Highlights: • A gas turbine cycle equipped with a double acting Stirling engine is proposed. • The hybrid cycle effects, efficiency and power outputs are investigated. • The energy dissipation, the net enthalpy loss and wall heat leakage are considered. • The hybrid cycle improves the efficiency from 23.6 to 38.8%. - Abstract: The aim of this study is to investigate the thermodynamic performance of a gas turbine cycle equipped with a double acting Stirling engine. A portion of gas turbine exhaust gases are allocated to providing the heat required for the Stirling engine. Employing this hybrid cycle improves gas turbine performance and power generation. The double acting Stirling engine is used in this study and the non-ideal adiabatic model is used to numerical solution. The regenerator’s net enthalpy loss, the regenerator’s wall heat leakage, the energy dissipation caused by pressure drops in heat exchangers and regenerator are the losses that were taken into account for the Stirling engine. The hybrid cycle, gas turbine governing equations and Stirling engine analyses are carried out using the Matlab software. The pressure ratio of the compressor, the inlet temperature of turbine, the porosity, length and diameter of the regenerator were chosen as essential parameters in this article. Also the hybrid cycle effects, efficiency and power outputs are investigated. The results show that the hybrid gas turbine and Stirling engine improves the efficiency from 23.6 to 38.8%.

  4. European Stirling forum 2000. Proceedings; Europaeisches Stirling Forum 2000. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This document comprises all 42 papers presented at the 'European Stirling Forum 2000', held in Osnabrueck on February 22-24, 2000. Among others, the following subjects were discussed: Thermodynamics, new developments, Stirling engines, free piston heat pumps, flow optimisation of regenerators for Stirling engines, simulation for modelling of flow and heat transfer in the gas cycle of Stirling engines, design and performance, Stirling refrigerators, economic efficiency of biomass Stirling engines, power control of a Stirling CHP system, a Stirling refrigerator for ultralow temperatures in the refrigeration industry. [German] Das vorliegende Dokument enthaelt alle (42) Beitraege der Referenten des 'Europaeischen Stirling Forums 2000', das vom 22. bis 24. Februar 2000 in Osnabrueck stattgefunden hat. Einige der behandelten Themenschwerpunkte im Zusammenhang mit der Stirling-Maschine waren die Thermodynamik, neue Entwicklungen des Kreisprozesses, Heissgasmotoren, Freikolben-Waermepumpe, stroemungstechnische Optimierung von Regeneratoren fuer Stirling-Maschinen, Simulation zur Modellierung der Stroemung und Waermeuebertragung im Gaskreislauf von Stirling-Maschinen, Entwurf und Betriebsverhalten, Stirling-Kaeltemaschine, Wirtschaftlichkeit von Biomasse-Stirlingmotoren, Leistungsregelung eines Stirling-Blockheizkraftwerks, Anwendung eines Stirling-Kuehlers, zum Ultratiefkuehlen in der Kuehlindustrie. (AKF)

  5. Nuclear Production of Hydrogen Using Thermochemical Water-Splitting Cycles

    International Nuclear Information System (INIS)

    Brown, L.C.; Besenbruch, G.E.; Schultz, K.R.; Marshall, A.C.; Showalter, S.K.; Pickard, P.S.; Funk, J.F.

    2002-01-01

    The purpose of this work is to determine the potential for efficient, cost-effective, large-scale production of hydrogen utilizing high-temperature heat from an advanced nuclear power station in a thermochemical water-splitting cycle. We carried out a detailed literature search to create a searchable database with 115 cycles and 822 references. We developed screening criteria to reduce the list to 25 cycles. We used detailed evaluation to select two cycles that appear most promising, the Adiabatic UT-3 cycle and the Sulfur-Iodine cycle. We have selected the Sulfur-Iodine thermochemical water-splitting cycle for further development. We then assessed the suitability of various nuclear reactor types to the production of hydrogen from water using the Sulfur-Iodine cycle. A basic requirement is to deliver heat to the process interface heat exchanger at temperatures up to 900 deg. C. We considered nine categories of reactors: pressurized water-cooled, boiling water-cooled, organic-cooled, alkali metal-cooled, heavy metal-cooled, gas-cooled, molten salt-cooled, liquid-core and gas-core reactors. We developed requirements and criteria to carry out the assessment, considering design, safety, operational, economic and development issues. This assessment process led to our choice of the helium gas-cooled reactor for coupling to the Sulfur-Iodine cycle. In continuing work, we are investigating the improvements that have been proposed to the Sulfur-Iodine cycle and will generate an integrated flowsheet describing a hydrogen production plant powered by a high-temperature helium gas-cooled nuclear reactor. This will allow us to size process equipment and calculate hydrogen production efficiency and capital cost, and to estimate the cost of the hydrogen produced as a function of nuclear reactor cost. (authors)

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

    Science.gov (United States)

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

    2015-09-01

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

  7. Influence of quantum degeneracy and regeneration on the performance of Bose-Stirling refrigeration-cycles operated in different temperature regions

    International Nuclear Information System (INIS)

    Lin Bihong; Zhang Yue; Chen Jincan

    2006-01-01

    The Stirling refrigeration cycle using an ideal Bose-gas as the working substance is called the Bose-Stirling refrigeration cycle, which is different from other thermodynamic cycles such as the Carnot cycle, Ericsson cycle, Brayton cycle, Otto cycle, Diesel cycle and Atkinson cycle working with an ideal Bose gas and may be operated across the critical temperature of Bose-Einstein condensation of the Bose system. The performance of the cycle is investigated, based on the equation of state of an ideal Bose gas. The inherent regenerative losses of the cycle are considered and the coefficient of performance and the amount of refrigeration of the cycle are calculated. The results obtained here are compared with those derived from the classical Stirling refrigeration cycle, using an ideal gas as the working substance. The influence of quantum degeneracy and inherent regenerative losses on the performance of the Bose Stirling refrigeration cycle operated in different temperature regions is discussed in detail, and consequently, general performance characteristics of the cycle are revealed

  8. Solar High Temperature Water-Splitting Cycle with Quantum Boost

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Robin [SAIC; Davenport, Roger [SAIC; Talbot, Jan [UCSD; Herz, Richard [UCSD; Genders, David [Electrosynthesis Co.; Symons, Peter [Electrosynthesis Co.; Brown, Lloyd [TChemE

    2014-04-25

    A sulfur family chemical cycle having ammonia as the working fluid and reagent was developed as a cost-effective and efficient hydrogen production technology based on a solar thermochemical water-splitting cycle. The sulfur ammonia (SA) cycle is a renewable and sustainable process that is unique in that it is an all-fluid cycle (i.e., with no solids handling). It uses a moderate temperature solar plant with the solar receiver operating at 800°C. All electricity needed is generated internally from recovered heat. The plant would operate continuously with low cost storage and it is a good potential solar thermochemical hydrogen production cycle for reaching the DOE cost goals. Two approaches were considered for the hydrogen production step of the SA cycle: (1) photocatalytic, and (2) electrolytic oxidation of ammonium sulfite to ammonium sulfate in aqueous solutions. Also, two sub-cycles were evaluated for the oxygen evolution side of the SA cycle: (1) zinc sulfate/zinc oxide, and (2) potassium sulfate/potassium pyrosulfate. The laboratory testing and optimization of all the process steps for each version of the SA cycle were proven in the laboratory or have been fully demonstrated by others, but further optimization is still possible and needed. The solar configuration evolved to a 50 MW(thermal) central receiver system with a North heliostat field, a cavity receiver, and NaCl molten salt storage to allow continuous operation. The H2A economic model was used to optimize and trade-off SA cycle configurations. Parametric studies of chemical plant performance have indicated process efficiencies of ~20%. Although the current process efficiency is technically acceptable, an increased efficiency is needed if the DOE cost targets are to be reached. There are two interrelated areas in which there is the potential for significant efficiency improvements: electrolysis cell voltage and excessive water vaporization. Methods to significantly reduce water evaporation are

  9. Copper oxide--copper sulfate water-splitting cycle

    Energy Technology Data Exchange (ETDEWEB)

    Foh, S. E.; Schreiber, J. D.; Dafler, J. R.

    1978-08-01

    A hybrid copper oxide--copper sulfate thermochemical water-splitting cycle, IGT's H-5, has been demonstrated in the laboratory with recycled materials. The optimum configuration and operating conditions for the electrolytic hydrogen-producing step have not yet been defined. With cooperative funding (A.G.A./G.R.I./DOE) a conceptual flowsheet was developed for this cycle and a load-line efficiency of about 37% calculated. This figure is the result of a single iteration on the original base case flow sheet and compares well with the values calculated for other processes at this stage of development. An iterative optimization of process conditions would improve efficiency. The data required to perform an economic analysis are not yet available and the electrolysis step must be more fully defined. An attractive process efficiency, relatively few corrosive materials, and few gas-phase separations are attributes of Cycle H-5 that lead us to believe hydrogen costs (to be developed during future analyses) would be improved significantly over similar processes analyzed to date.

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

    Science.gov (United States)

    Jaffe, Leonard D.

    1988-01-01

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

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

    Science.gov (United States)

    Jaffe, Leonard D.

    1988-11-01

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

  12. Application of the Open Cycle Stirling Engine Driven with Liquid Nitrogen for the Non-Polluting Automobiles

    Directory of Open Access Journals (Sweden)

    M.B. Kravchenko

    2017-10-01

    Full Text Available Progress on advancing technology of using liquid nitrogen for the non-polluting automobiles is reported. It is shown that the low exergy efficiency of the known engines fueled with liquid nitrogen has discredited the very idea of a cryomobile. The design of the open-cycle cryogenic Stirling engine is proposed. This engine allows extracting up to 57% of the exergy accumulated in liquid nitrogen. The method used to calculate of such open-cycle Stirling engine is described and the calculation results and discussion are presented. It is shown that 200 liters of liquid nitrogen is sufficient for 180 km range of cryomobile at speed of 55 km/h, while a full charge of the 300-kilogram battery of Nissan LEAF electric vehicle is sufficient for a range of 160 km. Use of liquid nitrogen or liquid air as an energy vector in a transport will not require scarce materials, and, in comparison with using of lithium-ion batteries or hydrogen, this will require less capital investment.

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

    Science.gov (United States)

    Jiang, Nan; Simon, Terrence W.

    2006-01-01

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

  14. Linear motor driven Stirling coolers for military and commercial applications

    International Nuclear Information System (INIS)

    Berry, R.

    1992-01-01

    This paper discusses the design and performance of a miniature, closed cycle, split stirling, cryogenic cooler that provides 1 watt of cooling at 80 K. The compressor uses two opposed linear motors to drive opposed pistons and the expander uses a pneumatically driven displacer. A single electronics module and compressor has been developed to drive three different expanders that have nominal cold cylinder diameters of 5, 8 and 13 mm

  15. Entropy Analysis of Solar Two-Step Thermochemical Cycles for Water and Carbon Dioxide Splitting

    Directory of Open Access Journals (Sweden)

    Matthias Lange

    2016-01-01

    Full Text Available The present study provides a thermodynamic analysis of solar thermochemical cycles for splitting of H2O or CO2. Such cycles, powered by concentrated solar energy, have the potential to produce fuels in a sustainable way. We extend a previous study on the thermodynamics of water splitting by also taking into account CO2 splitting and the influence of the solar absorption efficiency. Based on this purely thermodynamic approach, efficiency trends are discussed. The comprehensive and vivid representation in T-S diagrams provides researchers in this field with the required theoretical background to improve process development. Furthermore, results about the required entropy change in the used redox materials can be used as a guideline for material developers. The results show that CO2 splitting is advantageous at higher temperature levels, while water splitting is more feasible at lower temperature levels, as it benefits from a great entropy change during the splitting step.

  16. Thermodynamic analysis and system design of a novel split cycle engine concept

    International Nuclear Information System (INIS)

    Dong, Guangyu; Morgan, Robert E.; Heikal, Morgan R.

    2016-01-01

    The split cycle engine is a new reciprocating internal combustion engine with a potential of a radical efficiency improvement. In this engine, the compression and combustion–expansion processes occur in different cylinders. In the compression cylinder, the charge air is compressed through a quasi-isothermal process by direct cooling of the air. The high pressure air is then heated in a recuperator using the waste heat of exhaust gas before induction to the combustion cylinder. The combustion process occurs during the expansion stroke, in a quasi-isobaric process. In this paper, a fundamental theoretical cycle analysis and one-dimensional engine simulation of the split cycle engine was undertaken. The results show that the thermal efficiency (η) is mainly decided by the CR (compression ratio) and ER (expansion ratio), the regeneration effectiveness (σ), and the temperature rising ratio (N). Based on the above analysis, a system optimization of the engine was conducted. The results showed that by increasing CR from 23 to 25, the combustion and recuperation processes could be improved. By increasing the expansion ratio to 26, the heat losses during the gas exchange stroke were further reduced. Furthermore, the coolant temperatures of the compression and expansion chambers can be controlled separately to reduce the wall heat transfer losses. Compared to a conventional engine, a 21% total efficiency improvement was achieved when the split cycle was applied. It was concluded that through the system optimization, a total thermal efficiency of 53% can be achieved on split cycle engine. - Highlights: • Fundamental mechanism of the split cycle engine is investigated. • The key affecting factors of the thermodynamic cycle efficiency are identified. • The practical efficiency of split cycle applying on diesel engine is analysed. • The design optimization on the split cycle engine concept is conducted.

  17. Thermodynamic evaluation of the Kalina split-cycle concepts for waste heat recovery applications

    International Nuclear Information System (INIS)

    Nguyen, Tuong-Van; Knudsen, Thomas; Larsen, Ulrik; Haglind, Fredrik

    2014-01-01

    The Kalina split-cycle is a thermodynamic process for converting thermal energy into electrical power. It uses an ammonia–water mixture as a working fluid (like a conventional Kalina cycle) and has a varying ammonia concentration during the pre-heating and evaporation steps. This second feature results in an improved match between the heat source and working fluid temperature profiles, decreasing the entropy generation in the heat recovery system. The present work compares the thermodynamic performance of this power cycle with the conventional Kalina process, and investigates the impact of varying boundary conditions by conducting an exergy analysis. The design parameters of each configuration were determined by performing a multi-variable optimisation. The results indicate that the Kalina split-cycle with reheat presents an exergetic efficiency by 2.8% points higher than a reference Kalina cycle with reheat, and by 4.3% points without reheat. The cycle efficiency varies by 14% points for a variation of the exhaust gas temperature of 100 °C, and by 1% point for a cold water temperature variation of 30 °C. This analysis also pinpoints the large irreversibilities in the low-pressure turbine and condenser, and indicates a reduction of the exergy destruction by about 23% in the heat recovery system compared to the baseline cycle. - Highlights: • The thermodynamic performance of the Kalina split-cycle is assessed. • The Kalina split-cycle is compared to the Kalina cycle, with and without reheat. • An exergy analysis is performed to evaluate its thermodynamic performance. • The impact of varying boundary conditions is investigated. • The Kalina split-cycle displays high exergetic efficiency for low- and medium-temperature applications

  18. Overall performance of the duplex Stirling refrigerator

    International Nuclear Information System (INIS)

    Erbay, L. Berrin; Ozturk, M. Mete; Doğan, Bahadır

    2017-01-01

    Highlights: • Overall performance coefficient of duplex Stirling refrigerator was investigated. • A definite region for the coefficient of performance of the refrigerator in duplex Stirling is identified. • A definite region for the thermal efficiency of the heat engine in duplex Stirling is identified. • Benchmark values and design bounds of the duplex Stirling refrigerator were obtained. - Abstract: The duplex Stirling refrigerator is an integrated refrigerator consists of Stirling cycle engine and Stirling cycle refrigerator used for cooling. The equality of the work generation of the heat engine to the work consumption of the refrigerator is the primary constraint of the duplex Stirling. The duplex Stirling refrigerator is investigated thermodynamically by considering the effects of constructional and operational parameters which are namely the temperature ratios for heat engine and refrigerator, and the compression ratios for both sides. The primary concern is given to the parametric effects on the overall coefficient of performance of the duplex Stirling refrigerator. The given diagrams provide a design bounds and benchmark results that allows seeing the big picture about the cooling load and heat input relation. Moreover they ease to determine the corresponding work rate to the target cooling load. As regard to the obtained results, a definite region for coefficient of performance of the refrigerator and a definite region for the thermal efficiency of the heat engine of the duplex Stirling are identified.

  19. Performance analysis and optimization for generalized quantum Stirling refrigeration cycle with working substance of a particle confined in a general 1D potential

    Science.gov (United States)

    Yin, Yong; Chen, Lingen; Wu, Feng

    2018-03-01

    A generalized irreversible quantum Stirling refrigeration cycle (GIQSRC) is proposed. The working substance of the GIQSRC is a particle confined in a general 1D potential which energy spectrum can be expressed as εn = ℏωnσ . Heat leakage and non-ideal regeneration loss are taken into account. The expressions of coefficient of performance (COP) and dimensionless cooling load are obtained. The different practical cases of the energy spectrum are analyzed. The results of this paper are meaningful to understand the quantum thermodynamics cycles with a particle confined in different potential as working substance.

  20. A novel split cycle internal combustion engine with integral waste heat recovery

    International Nuclear Information System (INIS)

    Dong, Guangyu; Morgan, Robert; Heikal, Morgan

    2015-01-01

    Highlights: • A novel engine thermodynamic cycle is proposed. • Theoretical analysis is applied to identify the key parameters of the thermodynamic cycle. • The key stages of the split cycle are analysed via one-dimensional modelling work. • The effecting mechanism of the split cycle efficiency is analysed. - Abstract: To achieve a step improvement in engine efficiency, a novel split cycle engine concept is proposed. The engine has separate compression and combustion cylinders and waste heat is recovered between the two. Quasi-isothermal compression of the charge air is realised in the compression cylinder while isobaric combustion of the air/fuel mixture is achieved in the combustion cylinder. Exhaust heat recovery between the compression and combustion chamber enables highly efficient recovery of waste heat within the cycle. Based on cycle analysis and a one-dimensional engine model, the fundamentals and the performance of the split thermodynamic cycle is estimated. Compared to conventional engines, the compression work can be significantly reduced through the injection of a controlled quantity of water in the compression cylinder, lowering the gas temperature during compression. Thermal energy can then be effectively recovered from the engine exhaust in a recuperator between the cooled compressor cylinder discharge air and the exhaust gas. The resulting hot high pressure air is then injected into a combustor cylinder and mixed with fuel, where near isobaric combustion leads to a low combustion temperature and reduced heat transferred from the cylinder wall. Detailed cycle simulation indicates a 32% efficiency improvement can be expected compared to the conventional diesel engines.

  1. Solar Hydrogen Production via a Samarium Oxide-Based Thermochemical Water Splitting Cycle

    Directory of Open Access Journals (Sweden)

    Rahul Bhosale

    2016-04-01

    Full Text Available The computational thermodynamic analysis of a samarium oxide-based two-step solar thermochemical water splitting cycle is reported. The analysis is performed using HSC chemistry software and databases. The first (solar-based step drives the thermal reduction of Sm2O3 into Sm and O2. The second (non-solar step corresponds to the production of H2 via a water splitting reaction and the oxidation of Sm to Sm2O3. The equilibrium thermodynamic compositions related to the thermal reduction and water splitting steps are determined. The effect of oxygen partial pressure in the inert flushing gas on the thermal reduction temperature (TH is examined. An analysis based on the second law of thermodynamics is performed to determine the cycle efficiency (ηcycle and solar-to-fuel energy conversion efficiency (ηsolar−to−fuel attainable with and without heat recuperation. The results indicate that ηcycle and ηsolar−to−fuel both increase with decreasing TH, due to the reduction in oxygen partial pressure in the inert flushing gas. Furthermore, the recuperation of heat for the operation of the cycle significantly improves the solar reactor efficiency. For instance, in the case where TH = 2280 K, ηcycle = 24.4% and ηsolar−to−fuel = 29.5% (without heat recuperation, while ηcycle = 31.3% and ηsolar−to−fuel = 37.8% (with 40% heat recuperation.

  2. Thermodynamic evaluation of the Kalina split-cycle concepts for waste heat recovery applications

    DEFF Research Database (Denmark)

    Nguyen, Tuong-Van; Knudsen, Thomas; Larsen, Ulrik

    2014-01-01

    of varying boundary conditions by conducting an exergy analysis. The design parameters of each configuration were determined by performing a multi-variable optimisation. The results indicate that the Kalina split-cycle with reheat presents an exergetic efficiency by 2.8% points higher than a reference Kalina...... and condenser, and indicates a reduction of the exergy destruction by about 23% in the heat recovery system compared to the baseline cycle....

  3. MEMS Stirling Cooler Development Update

    Science.gov (United States)

    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.

  4. Stirling cryocooler test results and design model verification

    International Nuclear Information System (INIS)

    Shimko, M.A.; Stacy, W.D.; McCormick, J.A.

    1990-01-01

    This paper reports on progress in developing a long-life Stirling cycle cryocooler for space borne applications. It presents the results from tests on a preliminary breadboard version of the cryocooler used to demonstrate the feasibility of the technology and to validate the regenerator design code used in its development. This machine achieved a cold-end temperature of 65 K while carrying a 1/2 Watt cooling load. The basic machine is a double-acting, flexure-bearing, split Stirling design with linear electromagnetic drives for the expander and compressors. Flat metal diaphragms replace pistons for both sweeping and sealing the machine working volumes. In addition, the double-acting expander couples to a laminar-channel counterflow recuperative heat exchanger for regeneration. A PC compatible design code was developed for this design approach that calculates regenerator loss including heat transfer irreversibilities, pressure drop, and axial conduction in the regenerator walls

  5. Stirling Engine Controller

    Science.gov (United States)

    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

  6. Stirling to Flight Initiative

    Science.gov (United States)

    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

  7. Thermophysical properties of copper compounds in copper-chlorine thermochemical water splitting cycles

    International Nuclear Information System (INIS)

    Zamfirescu, C.; Dincer, I.; Naterer, G.F.

    2009-01-01

    This paper examines the relevant thermophysical properties of compounds of chlorine and copper that are found in thermochemical water splitting cycles. There are four variants of such Cu-Cl cycles that use heat and electricity to split the water molecule and produce H 2 and O 2 . Since the energy input is mainly in the form of thermal energy, the Cu-Cl water splitting cycle is much more efficient than water electrolysis, if the electricity generation efficiency for electrolysis is taken into account. A number of copper compounds (Cu 2 OCl 2 , CuO, CuCl 2 , CuCl) and other chemicals (Cu, HCl) are recycled within the plant, while the overall effect is splitting of the water molecule. The system includes a number of chemical reactors, heat exchangers, spray dryer and electrochemical cell. This paper identifies the available experimental data for properties of copper compounds relevant to the Cu-Cl cycle analysis and design. It also develops new regression formulas to correlate the properties, which include: specific heat, enthalpy, entropy, Gibbs free energy, density, formation enthalpy and free energy. No past literature data is available for the viscosity and thermal conductivity of molten CuCl, so estimates are provided. The properties are evaluated at 1 bar and a range of temperatures from ambient to 675-1000K, which are consistent with the operating conditions of the cycle. Updated calculations of chemical exergies are provided as follows: 21.08, 6.268, 82.474, and 75.0 kJ/mol for Cu 2 OCl 2 , CuO, CuCl 2 and CuCl, respectively. For molten CuCl, the estimated viscosity varies from 2.6 to 1.7mPa.s. (author)

  8. Stirling co-generation plants - Is this the future?; Stirling-BHKWs - Zukunft oder...?

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, M.

    2000-07-01

    This article gives an overview of the history and main features of Stirling engines and their use in combined-cycle power generation. The principles behind the Stirling and its thermo-dynamic characteristics are discussed and compared with the internal combustion engine and other thermally-driven machines. The two main types of Stirling - the free-piston and the kinematic Stirling engines are discussed. Also, the important role played by the burner in the operation of Stirling engines is discussed. The use of Stirling engines as a basis for small combined heat and power (CHP) units to produce thermal heating power and electricity is examined. Three examples - the implementations made by the Solo, Whispergen and SIG companies - are looked at in detail and compared with alternative CHP-solutions using small gas engines and fuel cells. The advantages and disadvantages of these different solutions are listed.

  9. Stirling engine design manual

    Science.gov (United States)

    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.

  10. Solar Metal Sulfate-Ammonia Based Thermochemical Water Splitting Cycle for Hydrogen Production

    Science.gov (United States)

    Huang, Cunping (Inventor); T-Raissi, Ali (Inventor); Muradov, Nazim (Inventor)

    2014-01-01

    Two classes of hybrid/thermochemical water splitting processes for the production of hydrogen and oxygen have been proposed based on (1) metal sulfate-ammonia cycles (2) metal pyrosulfate-ammonia cycles. Methods and systems for a metal sulfate MSO.sub.4--NH3 cycle for producing H2 and O2 from a closed system including feeding an aqueous (NH3)(4)SO3 solution into a photoctalytic reactor to oxidize the aqueous (NH3)(4)SO3 into aqueous (NH3)(2)SO4 and reduce water to hydrogen, mixing the resulting aqueous (NH3)(2)SO4 with metal oxide (e.g. ZnO) to form a slurry, heating the slurry of aqueous (NH4)(2)SO4 and ZnO(s) in the low temperature reactor to produce a gaseous mixture of NH3 and H2O and solid ZnSO4(s), heating solid ZnSO4 at a high temperature reactor to produce a gaseous mixture of SO2 and O2 and solid product ZnO, mixing the gaseous mixture of SO2 and O2 with an NH3 and H2O stream in an absorber to form aqueous (NH4)(2)SO3 solution and separate O2 for aqueous solution, recycling the resultant solution back to the photoreactor and sending ZnO to mix with aqueous (NH4)(2)SO4 solution to close the water splitting cycle wherein gaseous H2 and O2 are the only products output from the closed ZnSO4--NH3 cycle.

  11. Stirling engine design manual, 2nd edition

    Science.gov (United States)

    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. Stirling Microregenerators Fabricated and Tested

    Science.gov (United States)

    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. System analysis and optimisation of a Kalina split-cycle for waste heat recovery on large marine diesel engines

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Nguyen, Tuong-Van; Knudsen, Thomas

    2014-01-01

    Waste heat recovery systems can produce power from heat without using fuel or emitting CO2, therefore their implementation is becoming increasingly relevant. The Kalina cycle is proposed as an efficient process for this purpose. The main reason for its high efficiency is the non-isothermal phase...... change characteristics of the ammonia-water working fluid. The present study investigates a unique type of Kalina process called the Split-cycle, applied to the exhaust heat recovery from large marine engines. In the Split-cycle, the working fluid concentration can be changed during the evaporation...

  14. Analytical Solutions and Optimization of the Exo-Irreversible Schmidt Cycle with Imperfect Regeneration for the 3 Classical Types of Stirling Engine Solutions analytiques et optimisation du cycle de Schmidt irréversible à régénération imparfaite appliquées aux 3 types classiques de moteur Stirling

    Directory of Open Access Journals (Sweden)

    Rochelle P.

    2011-11-01

    Full Text Available The “old” Stirling engine is one of the most promising multi-heat source engines for the future. Simple and realistic basic models are useful to aid in optimizing a preliminary engine configuration. In addition to new proper analytical solutions for regeneration that dramatically reduce computing time, this study of the Schmidt-Stirling engine cycle is carried out from an engineer-friendly viewpoint introducing exo-irreversible heat transfers. The reference parameters are the technological or physical constraints: the maximum pressure, the maximum volume, the extreme wall temperatures and the overall thermal conductance, while the adjustable optimization variables are the volumetric compression ratio, the dead volume ratios, the volume phase-lag, the gas characteristics, the hot-to-cold conductance ratio and the regenerator efficiency. The new normalized analytical expressions for the operating characteristics of the engine: power, work, efficiency, mean pressure, maximum speed of revolution are derived, and some dimensionless and dimensional reference numbers are presented as well as power optimization examples with respect to non-dimensional speed, volume ratio and volume phase-lag angle.analytical solutions. Le “vieux” moteur Stirling est l’un des moteurs a sources multiples d’energie les plus prometteurs pour le futur. Des modeles elementaires simples et realistes sont utiles pour faciliter l’optimisation de configurations preliminaires du moteur. En plus de nouvelles solutions analytiques qui reduisent fortement le temps de calcul, cette etude du cycle moteur de Schmidt-Stirling modifie est entreprise avec le point de vue de l’ingenieur en introduisant les exo-irreversibilites dues aux transferts thermiques. Les parametres de reference sont des contraintes technologiques ou physiques : la pression maximum, le volume maximum, les temperatures de paroi extremes et la conductance totale, alors que les parametres d

  15. Method for controlling start-up and steady state performance of a closed split flow recompression brayton cycle

    Science.gov (United States)

    Pasch, James Jay

    2017-02-07

    A method of resolving a balanced condition that generates control parameters for start-up and steady state operating points and various component and cycle performances for a closed split flow recompression cycle system. The method provides for improved control of a Brayton cycle thermal to electrical power conversion system. The method may also be used for system design, operational simulation and/or parameter prediction.

  16. Studies on cycle characteristics and application of split heat pipe adsorption ice maker

    International Nuclear Information System (INIS)

    Chen, C.J.; Wang, R.Z.; Wang, L.W.; Lu, Z.S.

    2007-01-01

    A split heat pipe adsorption ice maker, which uses a solidified compound adsorbent (calcium chloride and activated carbon)-ammonia as working pair, is studied. The application of split heat pipe technology in this system (ice maker for fishing boat powered by waste heat of exhaust gases from diesel engine) solves the corrosion problem caused by using seawater to cool the adsorber directly. Therefore, the adsorbers can be cooled or heated by the working substance of the heat pipe in the adsorption or desorption state, respectively. There are two adsorbers in the adsorption ice maker, and each adsorber contains 2.35 kg compound adsorbent in which the mass of calcium chloride is 1.88 kg. The mass transfer performance and volume cooling density of the chemical adsorbent are greatly improved by the use of the compound adsorbent. Water is chosen as the working substance of the heat pipe due to its high cooling power in comparison with the experiments performed using acetone as working substance. When the cycle time is 70 min, the average SCP of ice making is about 329.8-712.8 W/kg calcium chloride with heat and mass recovery, which is approximately 1.6-3.5 times that of the best results of a conventional chemical adsorption ice maker

  17. Comparison of clinical outcomes between in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in IVF-ICSI split insemination cycles.

    Science.gov (United States)

    Lee, Sun Hee; Lee, Jae Hyun; Park, Yong-Seog; Yang, Kwang Moon; Lim, Chun Kyu

    2017-06-01

    This study aimed to compare the clinical outcomes between in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in sibling oocytes. Additionally, we evaluated whether the implementation of split insemination contributed to an increase in the number of ICSI procedures. A total of 571 cycles in 555 couples undergoing split insemination cycles were included in this study. Among them, 512 cycles (89.7%) were a couple's first IVF cycle. The patients were under 40 years of age and at least 10 oocytes were retrieved in all cycles. Sibling oocytes were randomly allocated to IVF or ICSI. Total fertilization failure was significantly more common in IVF cycles than in ICSI cycles (4.0% vs. 1.4%, p cycles than in IVF cycles (17.2% vs. 11.4%, p cycle and the second cycle, split insemination or ICSI was performed in 18 of the 95 cycles in which a second IVF cycle was performed. The clinical outcomes did not differ between IVF and ICSI in split insemination cycles. Split insemination can decrease the risk of total fertilization failure. However, unnecessary ICSI is carried out in most split insemination cycles and the use of split insemination might make ICSI more common.

  18. Structural design of Stirling engine with free pistons

    Science.gov (United States)

    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.

  19. Automotive Stirling engine: Mod 2 design report

    Science.gov (United States)

    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.

  20. Stirling Engine Configuration Selection

    Directory of Open Access Journals (Sweden)

    Jose Egas

    2018-03-01

    Full Text Available Unlike internal combustion engines, Stirling engines can be designed to work with many drive mechanisms based on the three primary configurations, alpha, beta and gamma. Hundreds of different combinations of configuration and mechanical drives have been proposed. Few succeed beyond prototypes. A reason for poor success is the use of inappropriate configuration and drive mechanisms, which leads to low power to weight ratio and reduced economic viability. The large number of options, the lack of an objective comparison method, and the absence of a selection criteria force designers to make random choices. In this article, the pressure—volume diagrams and compression ratios of machines of equal dimensions, using the main (alpha, beta and gamma crank based configurations as well as rhombic drive and Ross yoke mechanisms, are obtained. The existence of a direct relation between the optimum compression ratio and the temperature ratio is derived from the ideal Stirling cycle, and the usability of an empirical low temperature difference compression ratio equation for high temperature difference applications is tested using experimental data. It is shown that each machine has a different compression ratio, making it more or less suitable for a specific application, depending on the temperature difference reachable.

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

    International Nuclear Information System (INIS)

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

    1996-01-01

    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 1996 American Institute of Physics

  2. Use of TCSR with Split Windings for Shortening the Spar Cycle Time in 500 kV Lines

    Energy Technology Data Exchange (ETDEWEB)

    Matinyan, A. M., E-mail: al-drm@mail.ru; Peshkov, M. V.; Karpov, V. N.; Alekseev, N. A. [JSC “R& D Center at Federal Grid Company of Unified Power System,” (Russian Federation)

    2017-01-15

    The arc-fault recharge phenomenon in single-phase automatic reclosure (SPAR) of a line is examined. Abrief description is given of the design of a 500 kV thyristor controlled shunt reactor (TCSR) with split valve-side windings. This type of TCSR is shown to effectively quench a single-phase arc fault in a power transmission line and shortens the SPAR cycle time.

  3. Thermochemical water-splitting cycle, bench-scale investigations and process engineering. Annual report, October 1, 1978-September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Caprioglio, G.; McCorkle, K.H.; Besenbruch, G.E.; Rode, J.S.

    1980-03-01

    A program to investigate thermochemical water splitting has been under way at General Atomic Company (GA) since October 1972. This document is an annual progress report of Department of Energy (DOE) sponsored process development work on the GA sulfur-iodine thermochemical water splitting cycle. The work consisted of laboratory bench-scale investigations, demonstration of the process in a closed-loop cycle demonstrator, and process engineering design studies. A bench-scale system, consisting of three subunits, has been designed to study the cycle under continuous flow conditions. The designs of subunit I, which models the main solution reaction and product separation, and subunit II, which models the concentration and decomposition of sulfuric acid, were presented in an earlier annual report. The design of subunit III, which models the purification and decomposition of hydrogen iodide, is given in this report. Progress on the installation and operation of subunits I and II is described. A closed-loop cycle demonstrator was installed and operated based on a DOE request. Operation of the GA sulfur-iodine cycle was demonstrated in this system under recycle conditions. The process engineering addresses the flowsheet design of a large-scale production process consisting of four chemical sections (I through IV) and one helium heat supply section (V). The completed designs for sections I through V are presented. The thermal efficiency of the process calculated from the present flowsheet is 47%.

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

    Science.gov (United States)

    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.

  5. Management of the first in vitro fertilization cycle for unexplained infertility: a cost-effectiveness analysis of split in vitro fertilization-intracytoplasmic sperm injection.

    Science.gov (United States)

    Vitek, Wendy S; Galárraga, Omar; Klatsky, Peter C; Robins, Jared C; Carson, Sandra A; Blazar, Andrew S

    2013-11-01

    To determine the cost-effectiveness of split IVF-intracytoplasmic sperm injection (ICSI) for the treatment of couples with unexplained infertility. Adaptive decision model. Academic infertility clinic. A total of 154 couples undergoing a split IVF-ICSI cycle and a computer-simulated cohort of women IVF. Modeling insemination method in the first IVF cycle as all IVF, split IVF-ICSI, or all ICSI, and adapting treatment based on fertilization outcomes. Live birth rate, incremental cost-effectiveness ratio (ICER). In a single cycle, all IVF is preferred as the ICER of split IVF-ICSI or all ICSI ($58,766) does not justify the increased live birth rate (3%). If two cycles are needed, split IVF/ICSI is preferred as the increased cumulative live birth rate (3.3%) is gained at an ICER of $29,666. In a single cycle, all IVF was preferred as the increased live birth rate with split IVF-ICSI and all ICSI was not justified by the increased cost per live birth. If two IVF cycles are needed, however, split IVF/ICSI becomes the preferred approach, as a result of the higher cumulative live birth rate compared with all IVF and the lesser cost per live birth compared with all ICSI. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  6. High Performance Split-Stirling Cooler Program

    Science.gov (United States)

    1982-09-01

    or crankcase subassembly includes the two drive cranks 1800 apart, the two motor bearings, the flywheel and target wheel . This assembly is dynamically...DISPLACER SEAL FRICTION REGENERATOR FLOW @ lOPSI E"I’ •’ REGENERATOR RUNOUT COMP. BRG. LUBRICATION "COMP. PISTON SEAL COMP. PISTON SEAL FRICTION INTER

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

    Science.gov (United States)

    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.

  8. Maturing Technologies for Stirling Space Power Generation

    Science.gov (United States)

    Wilson, Scott D.; Nowlin, Brentley C.; Dobbs, Michael W.; Schmitz, Paul C.; Huth, James

    2016-01-01

    Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A Stirling Radioisotope Generator (SRG) could offer space missions a more efficient power system that uses one fourth of the nuclear fuel and decreases the thermal footprint of the current state of the art. The RPS Program Office, working in collaboration with the U.S. Department of Energy (DOE), manages projects to develop thermoelectric and dynamic power systems, including Stirling Radioisotope Generators (SRGs). The Stirling Cycle Technology Development (SCTD) Project, located at Glenn Research Center (GRC), is developing Stirling-based subsystems, including convertors and controllers. The SCTD Project also performs research that focuses on a wide variety of objectives, including increasing convertor temperature capability to enable new environments, improving system reliability or fault tolerance, reducing mass or size, and developing advanced concepts that are mission enabling. Research activity includes maturing subsystems, assemblies, and components to prepare them for infusion into future convertor and generator designs. The status of several technology development efforts are described here. As part of the maturation process, technologies are assessed for readiness in higher-level subsystems. To assess the readiness level of the Dual Convertor Controller (DCC), a Technology Readiness Assessment (TRA) was performed and the process and results are shown. Stirling technology research is being performed by the SCTD Project for NASA's RPS Program Office, where tasks focus on maturation of Stirling-based systems and subsystems for future space science missions.

  9. Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power

    International Nuclear Information System (INIS)

    Brown, L.C.; Funk, J.F.; Showalter, S.K.

    1999-01-01

    OAK B188 Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power There is currently no large scale, cost-effective, environmentally attractive hydrogen production process, nor is such a process available for commercialization. Hydrogen is a promising energy carrier, which potentially could replace the fossil fuels used in the transportation sector of our economy. Fossil fuels are polluting and carbon dioxide emissions from their combustion are thought to be responsible for global warming. The purpose of this work is to determine the potential for efficient, cost-effective, large-scale production of hydrogen utilizing high temperature heat from an advanced nuclear power station. Almost 800 literature references were located which pertain to thermochemical production of hydrogen from water and over 100 thermochemical watersplitting cycles were examined. Using defined criteria and quantifiable metrics, 25 cycles have been selected for more detailed study

  10. Fast Whole-Engine Stirling Analysis

    Science.gov (United States)

    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.

  11. Life cycle assessment of nuclear-based hydrogen production via thermochemical water splitting using a copper-chlorine (Cu-Cl) cycle

    Science.gov (United States)

    Ozbilen, Ahmet Ziyaettin

    The energy carrier hydrogen is expected to solve some energy challenges. Since its oxidation does not emit greenhouse gases (GHGs), its use does not contribute to climate change, provided that it is derived from clean energy sources. Thermochemical water splitting using a Cu-Cl cycle, linked with a nuclear super-critical water cooled reactor (SCWR), which is being considered as a Generation IV nuclear reactor, is a promising option for hydrogen production. In this thesis, a comparative environmental study is reported of the three-, four- and five-step Cu-Cl thermochemical water splitting cycles with various other hydrogen production methods. The investigation uses life cycle assessment (LCA), which is an analytical tool to identify and quantify environmentally critical phases during the life cycle of a system or a product and/or to evaluate and decrease the overall environmental impact of the system or product. The LCA results for the hydrogen production processes indicate that the four-step Cu-Cl cycle has lower environmental impacts than the three- and five-step Cu-Cl cycles due to its lower thermal energy requirement. Parametric studies show that acidification potentials (APs) and global warming potentials (GWPs) for the four-step Cu-Cl cycle can be reduced from 0.0031 to 0.0028 kg SO2-eq and from 0.63 to 0.55 kg CO2-eq, respectively, if the lifetime of the system increases from 10 to 100 years. Moreover, the comparative study shows that the nuclear-based S-I and the four-step Cu-Cl cycles are the most environmentally benign hydrogen production methods in terms of AP and GWP. GWPs of the S-I and the four-step Cu-Cl cycles are 0.412 and 0.559 kg CO2-eq for reference case which has a lifetime of 60 years. Also, the corresponding APs of these cycles are 0.00241 and 0.00284 kg SO2-eq. It is also found that an increase in hydrogen plant efficiency from 0.36 to 0.65 decreases the GWP from 0.902 to 0.412 kg CO 2-eq and the AP from 0.00459 to 0.00209 kg SO2-eq for the

  12. Ceramic applications in the advanced Stirling automotive engine

    Science.gov (United States)

    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.

  13. Ceria-based electrospun fibers for renewable fuel production via two-step thermal redox cycles for carbon dioxide splitting.

    Science.gov (United States)

    Gibbons, William T; Venstrom, Luke J; De Smith, Robert M; Davidson, Jane H; Jackson, Gregory S

    2014-07-21

    Zirconium-doped ceria (Ce(1-x)Zr(x)O2) was synthesized through a controlled electrospinning process as a promising approach to cost-effective, sinter-resistant material structures for high-temperature, solar-driven thermochemical redox cycles. To approximate a two-step redox cycle for solar fuel production, fibrous Ce(1-x)Zr(x)O2 with relatively low levels of Zr-doping (0 rates of O2 release during reduction and CO production during reoxidation and by assessing post-cycling fiber crystallite sizes and surface areas. Sintering increases with reduction temperature but occurs primarily along the fiber axes. Even after 108 redox cycles with reduction at 1400 °C and oxidation with CO2 at 800 °C, the fibers maintain their structure with surface areas of ∼0.3 m(2) g(-1), higher than those observed in the literature for other ceria-based structures operating at similarly high temperature conditions. Total CO production and peak production rate stabilize above 3.0 mL g(-1) and 13.0 mL min(-1) g(-1), respectively. The results show the potential for electrospun oxides as sinter-resistant material structures with adequate surface area to support rapid CO2 splitting in solar thermochemical redox cycles.

  14. Modular Stirling Radioisotope Generator

    Science.gov (United States)

    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

  15. Advanced Stirling Convertor (ASC) Technology Maturation

    Science.gov (United States)

    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

  16. Stirling engine application study

    Science.gov (United States)

    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.

  17. Hydrogen production by thermochemical cycles of water splitting coupled to a solar energy source

    International Nuclear Information System (INIS)

    Charvin, P.

    2007-11-01

    The aim of this work is to identify, to test and to estimate new thermochemical cycles able to efficiently produce hydrogen from concentrated solar energy. In fact, the aim is to propose a hydrogen production way presenting a global energetic yield similar to electrolysis, that is to say 20-25%, electrolysis being at the present time the most advanced current process for a clean hydrogen production from water. After a first chapter dealing with the past and present researches on thermochemical cycles, the first step of this study has consisted on a selection of a limited number of thermochemical cycles able to produce great quantities of hydrogen from concentrated solar energy. It has consisted in particular on a review of the thermochemical cycles present in literature, on a first selection from argued criteria, and on an exergetic and thermodynamic analysis of the retained cycles for a first estimation of their potential. The second step of this study deals with the experimental study of all the chemical reactions occurring in the retained cycles. Two different oxides cycles have been particularly chosen and the aims are to demonstrate the feasibility of the reactions, to identify the optimal experimental conditions, to estimate and optimize the kinetics and the chemical yields. The following part of this work deals with the design, the modeling and the test of a solar reactor. A CFD modeling of a high temperature reactor of cavity type allows to identify the main heat losses of the reactor and to optimize the geometry of the cavity. A dynamic modeling of the reactor gives data on its behaviour in transient regime and under a real solar flux. The results of the preliminary experimental results are presented. The last part of this study deals with a process analysis of the thermochemical cycles from the results of the experimental study (experimental conditions, yields...). The matter and energy balances are established in order to estimate the global energetic

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

    Science.gov (United States)

    Schreiber, Jeffrey G.; Skupinski, Robert C.

    2002-01-01

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

  19. Development of a multi-level approach to model and optimise the Kalina Split Cycle

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Nguyen, Tuong-Van; Haglind, Fredrik

    2012-01-01

    In the marine sector there is a strong motivation for increasing the propulsion system energy efficiency, mainly because of increasing fuel prices and stricter upcoming emission regulations. The Kalina cycle, based on a mixture of ammonia and water as working fluid, exhibits higher conversion...

  20. Commissioning and Performance Analysis of WhisperGen Stirling Engine

    Science.gov (United States)

    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.

  1. Thermodynamic analysis of SOFC (solid oxide fuel cell) - Stirling hybrid plants using alternative fuels

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2013-01-01

    A novel hybrid power system (∼10 kW) for an average family home is proposed. The system investigated contains a solid oxide fuel cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle are fed to a bottoming Stirling engine, at which additional power is generated...... to that of a stand-alone Stirling engine or SOFC plant. For the combined SOFC and Stirling configuration, the overall power production was increased by approximately 10% compared to that of a stand-alone SOFC plant. System efficiencies of approximately 60% are achieved, which is remarkable for such small plant sizes...

  2. Plant Characteristics af a Multi-Fuel Sofc-Stirling Hybrid Configuration

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2012-01-01

    A novel hybrid system ( kWe) for an average family house including heating is proposed. The system investigated, contains of a Solid Oxide Fuel Cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle is fed to the bottoming Stirling engine wherein additional power...... efficiency compared with the stand alone Stirling engine or SOFC plant. For the SOFC and Stirling combined configuration, the overall power production has increased by about 10% compared to the stand alone SOFC plant. System efficiencies of about 60% are achieved which is remarkable for such small plant...

  3. Development of a Stirling System Dynamic Model with Enhanced Thermodynamics

    Science.gov (United States)

    Regan, Timothy F.; Lewandowski, Edward J.

    2005-02-01

    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.

  4. Exergy analysis of a system using a chemical heat pump to link a supercritical water-cooled nuclear reactor and a thermochemical water splitting cycle

    International Nuclear Information System (INIS)

    Granovskii, M.; Dincer, I.; Rosen, M. A.; Pioro, I

    2007-01-01

    The power generation efficiency of nuclear plants is mainly determined by the permissible temperatures and pressures of the nuclear reactor fuel and coolants. These parameters are limited by materials properties and corrosion rates and their effect on nuclear reactor safety. The advanced materials for the next generation of CANDU reactors, which employ steam as a coolant and heat carrier, permit the increased steam parameters (outlet temperature up to 625 degree C and pressure of about 25 MPa). Supercritical water-cooled (SCW) nuclear power plants are expected to increase the power generation efficiency from 35 to 45%. Supercritical water-cooled nuclear reactors can be linked to thermochemical water splitting cycles for hydrogen production. An increased steam temperature from the nuclear reactor makes it also possible to utilize its energy in thermochemical water splitting cycles. These cycles are considered by many as one of the most efficient ways to produce hydrogen from water and to have advantages over traditional low-temperature water electrolysis. However, even lower temperature water splitting cycles (Cu-Cl, UT-3, etc.) require a heat supply at the temperatures over 550-600 degree C. A sufficient increase in the heat transfer from the nuclear reactor to a thermochemical water splitting cycle, without jeopardizing nuclear reactor safety, might be effectively achieved by application of a heat pump which increases the temperature the heat supplied by virtue of a cyclic process driven by mechanical or electrical work. A high temperature chemical heat pump which employs the reversible catalytic methane conversion reaction is proposed. The reaction shift from exothermic to endothermic and back is achieved by a change of the steam concentration in the reaction mixture. This heat pump, coupled with a SCW nuclear plant on one side and thermochemical water splitting cycle on the other, increases the temperature level of the 'nuclear' heat and, thus, the intensity of

  5. Comparison Based on Exergetic Analyses of Two Hot Air Engines: A Gamma Type Stirling Engine and an Open Joule Cycle Ericsson Engine

    Directory of Open Access Journals (Sweden)

    Houda Hachem

    2015-10-01

    Full Text Available In this paper, a comparison of exergetic models between two hot air engines (a Gamma type Stirling prototype having a maximum output mechanical power of 500 W and an Ericsson hot air engine with a maximum power of 300 W is made. Referring to previous energetic analyses, exergetic models are set up in order to quantify the exergy destruction and efficiencies in each type of engine. The repartition of the exergy fluxes in each part of the two engines are determined and represented in Sankey diagrams, using dimensionless exergy fluxes. The results show a similar proportion in both engines of destroyed exergy compared to the exergy flux from the hot source. The compression cylinders generate the highest exergy destruction, whereas the expansion cylinders generate the lowest one. The regenerator of the Stirling engine increases the exergy resource at the inlet of the expansion cylinder, which might be also set up in the Ericsson engine, using a preheater between the exhaust air and the compressed air transferred to the hot heat exchanger.

  6. Analysis of the hybrid copper oxide-copper sulfate cycle for the thermochemical splitting of water for hydrogen production

    International Nuclear Information System (INIS)

    Gonzales, Ross B.; Law, Victor J.; Prindle, John C.

    2009-01-01

    The hybrid copper oxide-copper sulfate water-splitting thermochemical cycle involves two principal steps: (1) hydrogen production from the electrolysis of water, SO 2 (g) and CuO(s) at room temperature and (2) the thermal decomposition of the CuSO 4 product to form oxygen and SO 2 , which is recycled to the first step. A four-reaction version of the cycle (known in the literature as Cycle H-5) was used as the basis of the present work. For several of the four reactions, a rotating batch reactor sequence is proposed in order to overcome equilibrium limitations. Pinch technology was used to optimize heat integration. Sensitivity analyses revealed it to be economically more attractive to use a 10 C approach to minimize heat loss (rather than 20 C). Using standard Aspen Plus features and the Peng-Robinson equation of state for separations involving oxygen and sulfur oxides, a proposed flowsheet for the cycle was generated to yield ''Level 3'' results. A cost analysis of the designed plant (producing 100 million kmol/yr hydrogen) indicates a total major equipment cost of approximately $45 million. This translates to a turnkey plant price (excluding the cost of the high-temperature heat source or electrolyzer internals) of approximately $360 million. Based on a $2.50/kg selling price for hydrogen, gross annual revenue could be on the order of $500 million, resulting in a reasonable payback period when all capital and operating costs are considered. Previous efficiency estimates using Level 1 and Level 2 methods gave the process efficiency in the neighborhood of 47-48%. The Level 3 efficiency computation was 24-25% depending on the approach temperature used for recuperation. If the low quality heat rejected by the process can be recovered and used elsewhere, the Level 3 analysis could be as high as 51-53%. (author)

  7. Cool down time optimization of the Stirling cooler

    Science.gov (United States)

    Xia, M.; Chen, X. P.; Y Li, H.; Gan, Z. H.

    2017-12-01

    The cooling power is one of the most important performances of a Stirling cooler. However, in some special fields, the cool down time is more important. It is a great challenge to improve the cool down time of the Stirling cooler. A new split Stirling linear cryogenic cooler SCI09H was designed in this study. A new structure of linear motor is used in the compressor, and the machine spring is used in the expander. In order to reduce the cool down time, the stainless-steel mesh of regenerator is optimized. The weight of the cooler is 1.1 kg, the cool down time to 80K is 2 minutes at 296K with a 250J thermal mass, the cooling power is 1.1W at 80K, and the input power is 50W.

  8. How to Achieve Supply Chain Sustainability Efficiently? Taming the Triple Bottom Line Split Business Cycle

    Directory of Open Access Journals (Sweden)

    Matthias Klumpp

    2018-02-01

    Full Text Available For sustainable supply chains, specific concepts regarding how to efficiently improve sustainability are needed in a global comprehensive triple bottom line (TBL approach, especially for forwarders as central actors in supply chain design. Such specific advice is provided by reporting empirical DEA Malmquist index findings from seven large European forwarders regarding a TBL sustainability analysis from 2006 to 2016. A major obstacle in improving sustainability consists in the newly discovered fact that with the business cycle, the three TBL areas of economic, ecologic and social objectives for logistics are undergoing different up- and down-ward trends, making it very hard to improve all three simultaneously. Additional factors are identified in the characteristics of size and government influence regarding the sustainability efficiency of forwarders. This has important impacts on supply chain design like e.g., with selection criteria.

  9. Maximum Work of Free-Piston Stirling Engine Generators

    Science.gov (United States)

    Kojima, Shinji

    2017-04-01

    Using the method of adjoint equations described in Ref. [1], we have calculated the maximum thermal efficiencies that are theoretically attainable by free-piston Stirling and Carnot engine generators by considering the work loss due to friction and Joule heat. The net work done by the Carnot cycle is negative even when the duration of heat addition is optimized to give the maximum amount of heat addition, which is the same situation for the Brayton cycle described in our previous paper. For the Stirling cycle, the net work done is positive, and the thermal efficiency is greater than that of the Otto cycle described in our previous paper by a factor of about 2.7-1.4 for compression ratios of 5-30. The Stirling cycle is much better than the Otto, Brayton, and Carnot cycles. We have found that the optimized piston trajectories of the isothermal, isobaric, and adiabatic processes are the same when the compression ratio and the maximum volume of the same working fluid of the three processes are the same, which has facilitated the present analysis because the optimized piston trajectories of the Carnot and Stirling cycles are the same as those of the Brayton and Otto cycles, respectively.

  10. Stirling engine piston ring

    Science.gov (United States)

    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.

  11. A Stirling Idea

    Science.gov (United States)

    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.

  12. Stirling in Another Context.

    Science.gov (United States)

    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)

  13. The Stirling engine accelerates.; Der Stirling-Motor gibt Gas.

    Energy Technology Data Exchange (ETDEWEB)

    Pfannstiel, Dieter [DiWiTech - Ingenieurpraxis fuer technische und wissenschaftliche Dienstleistungen, Breitenbach a.H. (Germany)

    2010-01-15

    At this moment, Stirling engines are the most outstanding micro technology of combined heat and power generation. The free piston machine combines the principle of the conventional Stirling engine with a modern linear generator for power generation utilizing waste heat for the heating of houses or hot water tanks. All large manufacturers concern themselves with this technology and develop devices based on the Stirling engine. The overview contribution under consideration describes the current level of development of the Stirling devices of different manufacturers. In nearly two years, these devices will serially be produced in the market.

  14. Optimal allocation and sizing of PV/Wind/Split-diesel/Battery hybrid energy system for minimizing life cycle cost, carbon emission and dump energy of remote residential building

    International Nuclear Information System (INIS)

    Ogunjuyigbe, A.S.O.; Ayodele, T.R.; Akinola, O.A.

    2016-01-01

    Highlights: • Genetic Algorithm is used for tri-objective design of hybrid energy system. • The objective is minimizing the Life Cycle Cost, CO_2 emissions and dump energy. • Small split diesel generators are used in place of big single diesel generator. • The split diesel generators are aggregable based on certain set of rules. • The proposed algorithm achieves the set objectives (LCC, CO_2 emission and dump). - Abstract: In this paper, a Genetic Algorithm (GA) is utilized to implement a tri-objective design of a grid independent PV/Wind/Split-diesel/Battery hybrid energy system for a typical residential building with the objective of minimizing the Life Cycle Cost (LCC), CO_2 emissions and dump energy. To achieve some of these objectives, small split Diesel generators are used in place of single big Diesel generator and are aggregable based on certain set of rules depending on available renewable energy resources and state of charge of the battery. The algorithm was utilized to study five scenarios (PV/Battery, Wind/Battery, Single big Diesel generator, aggregable 3-split Diesel generators, PV/Wind/Split-diesel/Battery) for a typical load profile of a residential house using typical wind and solar radiation data. The results obtained revealed that the PV/Wind/Split-diesel/Battery is the most attractive scenario (optimal) having LCC of $11,273, COE of 0.13 ($/kW h), net dump energy of 3 MW h, and net CO_2 emission of 13,273 kg. It offers 46%, 28%, 82% and 94% reduction in LCC, COE, CO_2 emission and dump energy respectively when compared to a single big Diesel generator scenario.

  15. Coefficient of performance of Stirling refrigerators

    Science.gov (United States)

    E Mungan, Carl

    2017-09-01

    Stirling coolers transfer heat in or out of the working fluid during all four stages of their operation, and their coefficient of performance depends on whether the non-isothermal heat exchanges are performed reversibly or irreversibly. Both of these possibilities can in principle be arranged. Notably, if the working fluid is an ideal gas, the input of energy in the form of heat during one isochoric step is equal in magnitude to the output during the other isochoric step in the cycle. The theoretical performance of the fridge can then attain the reversible Carnot limit if a regenerator is used, which is a high heat capacity material through which the gas flows. Various Stirling refrigerator configurations are analysed in this article at a level of presentation suitable for an introductory undergraduate thermodynamics course.

  16. Splitting CO2 with a ceria‐based redox cycle in a solar‐driven thermogravimetric analyzer

    Science.gov (United States)

    Takacs, M.; Ackermann, S.; Bonk, A.; Neises‐von Puttkamer, M.; Haueter, Ph.; Scheffe, J. R.; Vogt, U. F.

    2016-01-01

    Thermochemical splitting of CO2 via a ceria‐based redox cycle was performed in a solar‐driven thermogravimetric analyzer. Overall reaction rates, including heat and mass transport, were determined under concentrated irradiation mimicking realistic operation of solar reactors. Reticulated porous ceramic (RPC) structures and fibers made of undoped and Zr4+‐doped CeO2, were endothermally reduced under radiative fluxes of 1280 suns in the temperature range 1200–1950 K and subsequently re‐oxidized with CO2 at 950–1400 K. Rapid and uniform heating was observed for 8 ppi ceria RPC with mm‐sized porosity due to its low optical thickness and volumetric radiative absorption, while ceria fibers with μm‐sized porosity performed poorly due to its opacity to incident irradiation. The 10 ppi RPC exhibited higher fuel yield because of its higher sample density. Zr4+‐doped ceria showed increasing reduction extents with dopant concentration but decreasing specific CO yield due to unfavorable oxidation thermodynamics and slower kinetics. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1263–1271, 2017 PMID:28405030

  17. Splitting CO2 with a ceria-based redox cycle in a solar-driven thermogravimetric analyzer.

    Science.gov (United States)

    Takacs, M; Ackermann, S; Bonk, A; Neises-von Puttkamer, M; Haueter, Ph; Scheffe, J R; Vogt, U F; Steinfeld, A

    2017-04-01

    Thermochemical splitting of CO 2 via a ceria-based redox cycle was performed in a solar-driven thermogravimetric analyzer. Overall reaction rates, including heat and mass transport, were determined under concentrated irradiation mimicking realistic operation of solar reactors. Reticulated porous ceramic (RPC) structures and fibers made of undoped and Zr 4+ -doped CeO 2 , were endothermally reduced under radiative fluxes of 1280 suns in the temperature range 1200-1950 K and subsequently re-oxidized with CO 2 at 950-1400 K. Rapid and uniform heating was observed for 8 ppi ceria RPC with mm-sized porosity due to its low optical thickness and volumetric radiative absorption, while ceria fibers with μm-sized porosity performed poorly due to its opacity to incident irradiation. The 10 ppi RPC exhibited higher fuel yield because of its higher sample density. Zr 4+ -doped ceria showed increasing reduction extents with dopant concentration but decreasing specific CO yield due to unfavorable oxidation thermodynamics and slower kinetics. © 2016 American Institute of Chemical Engineers , 63: 1263-1271, 2017.

  18. Thermodynamic analysis of the use a chemical heat pump to link a supercritical water-cooled nuclear reactor and a thermochemical water-splitting cycle for hydrogen production

    International Nuclear Information System (INIS)

    Granovskii, Mikhail; Dincer, Ibrahim; Rosen, Marc A.; Pioro, Igor

    2008-01-01

    Increases in the power generation efficiency of nuclear power plants (NPPs) are mainly limited by the permissible temperatures in nuclear reactors and the corresponding temperatures and pressures of the coolants in reactors. Coolant parameters are limited by the corrosion rates of materials and nuclear-reactor safety constraints. The advanced construction materials for the next generation of CANDU reactors, which employ supercritical water (SCW) as a coolant and heat carrier, permit improved 'steam' parameters (outlet temperatures up to 625degC and pressures of about 25 MPa). An increase in the temperature of steam allows it to be utilized in thermochemical water splitting cycles to produce hydrogen. These methods are considered by many to be among the most efficient ways to produce hydrogen from water and to have advantages over traditional low-temperature water electrolysis. However, even lower temperature water splitting cycles (Cu-Cl, UT-3, etc.) require an intensive heat supply at temperatures higher than 550-600degC. A sufficient increase in the heat transfer from the nuclear reactor to a thermochemical water splitting cycle, without jeopardizing nuclear reactor safety, might be effectively achieved by application of a heat pump, which increases the temperature of the heat supplied by virtue of a cyclic process driven by mechanical or electrical work. Here, a high-temperature chemical heat pump, which employs the reversible catalytic methane conversion reaction, is proposed. The reaction shift from exothermic to endothermic and back is achieved by a change of the steam concentration in the reaction mixture. This heat pump, coupled with the second steam cycle of a SCW nuclear power generation plant on one side and a thermochemical water splitting cycle on the other, increases the temperature of the 'nuclear' heat and, consequently, the intensity of heat transfer into the water splitting cycle. A comparative preliminary thermodynamic analysis is conducted of

  19. Numerical model for predicting thermodynamic cycle and thermal efficiency of a beta-type Stirling engine with rhombic-drive mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Chin-Hsiang; Yu, Ying-Ju [Department of Aeronautics and Astronautics, National Cheng Kung University, No. 1, Ta-Shieh Road, Tainan 70101, Taiwan (China)

    2010-11-15

    This study is aimed at development of a numerical model for a beta-type Stirling engine with rhombic-drive mechanism. By taking into account the non-isothermal effects, the effectiveness of the regenerative channel, and the thermal resistance of the heating head, the energy equations for the control volumes in the expansion chamber, the compression chamber, and the regenerative channel can be derived and solved. Meanwhile, a fully developed flow velocity profile in the regenerative channel, in terms of the reciprocating velocity of the displacer and the instantaneous pressure difference between the expansion and the compression chambers, is derived for calculation of the mass flow rate through the regenerative channel. In this manner, the internal irreversibility caused by pressure difference in the two chambers and the viscous shear effects due to the motion of the reciprocating displacer on the fluid flow in the regenerative channel gap are included. Periodic variation of pressures, volumes, temperatures, masses, and heat transfers in the expansion and the compression chambers are predicted. A parametric study of the dependence of the power output and thermal efficiency on the geometrical and physical parameters, involving regenerative gap, distance between two gears, offset distance from the crank to the center of gear, and the heat source temperature, has been performed. (author)

  20. Stirling engine power control

    Science.gov (United States)

    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.

  1. Stirling Engine with Unidirectional Gas Flow

    OpenAIRE

    Blumbergs, Ilmars

    2014-01-01

    In this study, a Stirling engine with unidirectional gas flow configuration of beta type Stirling engine is described and studied from kinematic and thermodynamics points of view. Some aspects of the Stirling engine with unidirectional gas flow engine are compared to classic beta type Stirling engines. The aim of research has been to develop a new type of Stirling engine, using SolidWorks 3D design software and Flow Simulation software. In the development process, special attention has been d...

  2. Simulation of Temperature Fluctuations in Stirling Engine Regenerator Matrices

    DEFF Research Database (Denmark)

    Andersen, Stig Kildegaard; Carlsen, Henrik; Thomsen, Per Grove

    2003-01-01

    The objective of this study has been to create a model for studying the effects of fluctuations in regenerator matrix temperatures on Stirling engine performance. A one-dimensional model with axial discretisation of engine components has been formulated using the balance equations for mass, energy...... and accurately calculated. Simulation results have been compared to experimental data for a 9 kW Stirling engine and reasonable agreement has been found over a wide range of operating conditions using Helium or Nitrogen as working gas. Simulation results indicate that fluctuations in the regenerator matrix...... temperatures have significant impact on the regenerator loss, the engine power output, and the cycle efficiency....

  3. Effective multi-objective optimization of Stirling engine systems

    International Nuclear Information System (INIS)

    Punnathanam, Varun; Kotecha, Prakash

    2016-01-01

    Highlights: • Multi-objective optimization of three recent Stirling engine models. • Use of efficient crossover and mutation operators for real coded Genetic Algorithm. • Demonstrated supremacy of the strategy over the conventionally used algorithm. • Improvements of up to 29% in comparison to literature results. - Abstract: In this article we demonstrate the supremacy of the Non-dominated Sorting Genetic Algorithm-II with Simulated Binary Crossover and Polynomial Mutation operators for the multi-objective optimization of Stirling engine systems by providing three examples, viz., (i) finite time thermodynamic model, (ii) Stirling engine thermal model with associated irreversibility and (iii) polytropic finite speed based thermodynamics. The finite time thermodynamic model involves seven decision variables and consists of three objectives: output power, thermal efficiency and rate of entropy generation. In comparison to literature, it was observed that the used strategy provides a better Pareto front and leads to improvements of up to 29%. The performance is also evaluated on a Stirling engine thermal model which considers the associated irreversibility of the cycle and consists of three objectives involving eleven decision variables. The supremacy of the suggested strategy is also demonstrated on the experimentally validated polytropic finite speed thermodynamics based Stirling engine model for optimization involving two objectives and ten decision variables.

  4. Thermodynamic comparison of Peltier, Stirling, and vapor compression portable coolers

    International Nuclear Information System (INIS)

    Hermes, Christian J.L.; Barbosa, Jader R.

    2012-01-01

    Highlights: ► A Peltier, a Stirling, and two vapor compression refrigerators were compared. ► Tests were carried out to obtain key performance parameters of the systems. ► The overall 2nd-law efficiency was splited to take into account the internal and external irreversibilities. ► The Stirling and vapor compression refrigeration systems presented higher efficiencies. ► The thermoelectric device was not at the same efficiency level as the other coolers. -- Abstract: The present study compares the thermodynamic performance of four small-capacity portable coolers that employ different cooling technologies: thermoelectric, Stirling, and vapor compression using two different compressors (reciprocating and linear). The refrigeration systems were experimentally evaluated in a climatized chamber with controlled temperature and humidity. Tests were carried out at two different ambient temperatures (21 and 32 °C) in order to obtain key performance parameters of the systems (e.g., power consumption, cooling capacity, internal air temperature, and the hot end and cold end temperatures). These performance parameters were compared using a thermodynamic approach that splits the overall 2nd law efficiency into two terms, namely, the internal and external efficiencies. In doing so, the internal irreversibilities (e.g., friction in the working fluid in the Stirling and vapor compression machines, Joule heating and heat conduction in the thermoelectric devices of the Peltier cooler) were separated from the heat exchanger losses (external irreversibilities), allowing the comparison between different refrigeration technologies with respect to the same thermodynamic baseline.

  5. Integrated two-cylinder liquid piston Stirling engine

    Science.gov (United States)

    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.

  6. Integrated two-cylinder liquid piston Stirling engine

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ning; Rickard, Robert; Pluckter, Kevin; Sulchek, Todd, E-mail: todd.sulchek@me.gatech.edu [George W. Woodruff School of Mechanical Engineering and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    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.

  7. Integrated two-cylinder liquid piston Stirling engine

    International Nuclear Information System (INIS)

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

    2014-01-01

    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.

  8. Thermodynamic design of Stirling engine using multi-objective particle swarm optimization algorithm

    International Nuclear Information System (INIS)

    Duan, Chen; Wang, Xinggang; Shu, Shuiming; Jing, Changwei; Chang, Huawei

    2014-01-01

    Highlights: • An improved thermodynamic model taking into account irreversibility parameter was developed. • A multi-objective optimization method for designing Stirling engine was investigated. • Multi-objective particle swarm optimization algorithm was adopted in the area of Stirling engine for the first time. - Abstract: In the recent years, the interest in Stirling engine has remarkably increased due to its ability to use any heat source from outside including solar energy, fossil fuels and biomass. A large number of studies have been done on Stirling cycle analysis. In the present study, a mathematical model based on thermodynamic analysis of Stirling engine considering regenerative losses and internal irreversibilities has been developed. Power output, thermal efficiency and the cycle irreversibility parameter of Stirling engine are optimized simultaneously using Particle Swarm Optimization (PSO) algorithm, which is more effective than traditional genetic algorithms. In this optimization problem, some important parameters of Stirling engine are considered as decision variables, such as temperatures of the working fluid both in the high temperature isothermal process and in the low temperature isothermal process, dead volume ratios of each heat exchanger, volumes of each working spaces, effectiveness of the regenerator, and the system charge pressure. The Pareto optimal frontier is obtained and the final design solution has been selected by Linear Programming Technique for Multidimensional Analysis of Preference (LINMAP). Results show that the proposed multi-objective optimization approach can significantly outperform traditional single objective approaches

  9. Single-piston alternative to Stirling engines

    International Nuclear Information System (INIS)

    Glushenkov, Maxim; Sprenkeler, Martin; Kronberg, Alexander; Kirillov, Valeriy

    2012-01-01

    Highlights: ► Thermodynamic analysis of an unconventional heat engine. ► The engine has a number of advantages compared to state-of-the-art Stirling engines. ► The engine can to be fuelled with “difficult” fuels and used for micro-CHP systems. ► The energy conversion efficiency can be as high as 40–50%. ► A prototype of the engine was demonstrated. -- Abstract: Thermodynamic analysis of an unconventional heat engine was performed. The engine studied has a number of advantages compared to state-of-the-art Stirling engines. The main advantage of the engine proposed is its simplicity. A power piston is integral with a displacer and a heat regenerator. It allows solving the problem of the high-temperature sealing of the piston and the displacer typical of all types of Stirling engines. In addition the design proposed provides ideal use of the displacer volume eliminating heat losses from outside gas circuit. Both strokes of the piston are working ones in contrary to any other types of piston engines. The engine can be considered as maintenance-free as it has no piston rings or any other rubbing components requiring lubrication. The only seal is contactless and wear free. It is located in the cold part of the cylinder. As a result the leakage rate in operation can be one-two orders of magnitude as small as that in Stirling engines. Balancing of the engine is much easy compared to Stirling engines with two reciprocating masses because of the only moving part inside the engine cylinder. The engine suits ideally to be fuelled with “difficult” fuels such as bio oil and can be used as a prime mover for micro-CHP systems. The thermodynamic model developed incorporates non-ideal features of the cycle, such as specific regenerator efficiency, dead volumes and other geometrical parameters of the engine. The model shows that the energy efficiency is highly sensitive to regenerator performance. For realistic geometric and operating parameters and the

  10. Embryo splitting

    Directory of Open Access Journals (Sweden)

    Karl Illmensee

    2010-04-01

    Full Text Available Mammalian embryo splitting has successfully been established in farm animals. Embryo splitting is safely and efficiently used for assisted reproduction in several livestock species. In the mouse, efficient embryo splitting as well as single blastomere cloning have been developed in this animal system. In nonhuman primates embryo splitting has resulted in several pregnancies. Human embryo splitting has been reported recently. Microsurgical embryo splitting under Institutional Review Board approval has been carried out to determine its efficiency for blastocyst development. Embryo splitting at the 6–8 cell stage provided a much higher developmental efficiency compared to splitting at the 2–5 cell stage. Embryo splitting may be advantageous for providing additional embryos to be cryopreserved and for patients with low response to hormonal stimulation in assisted reproduction programs. Social and ethical issues concerning embryo splitting are included regarding ethics committee guidelines. Prognostic perspectives are presented for human embryo splitting in reproductive medicine.

  11. The Stirling engine

    International Nuclear Information System (INIS)

    Dunn, P.D.

    1989-01-01

    The Stirling engine can be used with any heat source including direct flame, heating from oil, gas, wood or coal combustors, by solar and by nuclear energy. As an alternative to conventional combustors fuels such as coal, oil, gas, vegetable waste can be combusted in a fluidized bed. The engine can be heated by coupling it directly to one of these sources of heat or it can be separated from the heat source and the heat transported by a heat pipe. There is clearly considerable flexibility in the choice of heat source. A major economic penalty is the need for a high temperature heat exchanger to transfer the heat to the engine working fluid from the heat source. Since in order to achieve good heat transfer a large surface area is needed and hence a complicated arrangement of small bore piping. Since the working fluid is not consumed an expensive substance such as helium can be used; however, if the power is to be extracted by a mechanical shaft it is necessary to design a seal between the engine body and the output shaft which will not allow any significant loss of helium. The seal problem is still one of the major technical difficulties in the development of Stirling engines using Helium or Hydrogen as the working fluid. For this reason interest in using air as the working fluid in lower speed engines has revived. 14 refs, 19 figs

  12. Advanced Stirling Convertor Update

    Science.gov (United States)

    Wood, J. Gary; Carroll, Cliff; Matejczyk, Dan; Penswick, L. B.; Soendker, E.

    2006-01-01

    This paper reports on the 88 We Advanced Stirling Convertor (ASC) currently being developed under Phase II of a NASA NRA program for possible use in advanced high specific power radioisotope space power systems. An early developmental unit, the Frequency Test Bed (FTB) which was built and tested in Phase I demonstrated 36% efficiency. The ASC-1 currently being developed under Phase II, uses a high temperature heater head to allow for operation at 850 °C and is expected to have an efficiency approaching 40% (based on AC electrical out) at a temperature ratio of 3.1. The final lightweight ASC-2 convertor to be developed in Phase III is expected to have a mass of approximately 1 kg. The implementation of the ASC would allow for much higher specific power radioisotope power systems, requiring significantly less radioisotope fuel than current systems. The first run of the ASC-1 occurred in September 2005, and full temperature operation was achieved in early October 2005. Presented is an update on progress on the ASC program as well as the plans for future development. Also presented are efforts being performed to ensure the ASC has the required long life already demonstrated in free-piston Stirling cryocoolers.

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

    Science.gov (United States)

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

    2014-02-01

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

  14. Free-piston Stirling technology for space power

    International Nuclear Information System (INIS)

    Slaby, J.G.

    1994-01-01

    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 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

  15. Hydrogen production system based on high temperature gas cooled reactor energy using the sulfur-iodine (SI) thermochemical water splitting cycle

    International Nuclear Information System (INIS)

    Garcia, L.; Gonzalez, D.

    2011-01-01

    Hydrogen production from water using nuclear energy offers one of the most attractive zero-emission energy strategies and the only one that is practical on a substantial scale. Recently, strong interest is seen in hydrogen production using heat of a high-temperature gas-cooled reactor. The high-temperature characteristics of the modular helium reactor (MHR) make it a strong candidate for producing hydrogen using thermochemical or high-temperature electrolysis (HTE) processes. Eventually it could be also employ a high-temperature gas-cooled reactor (HTGR), which is particularly attractive because it has unique capability, among potential future generation nuclear power options, to produce high-temperature heat ideally suited for nuclear-heated hydrogen production. Using heat from nuclear reactors to drive a sulfur-iodine (SI) thermochemical hydrogen production process has been interest of many laboratories in the world. One of the promising approaches to produce large quantity of hydrogen in an efficient way using the nuclear energy is the sulfur-iodine (SI) thermochemical water splitting cycle. Among the thermochemical cycles, the sulfur iodine process remains a very promising solution in matter of efficiency and cost. This work provides a pre-conceptual design description of a SI-Based H2-Nuclear Reactor plant. Software based on chemical process simulation (CPS) was used to simulate the thermochemical water splitting cycle Sulfur-Iodine for hydrogen production. (Author)

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

    Science.gov (United States)

    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.

  17. Simulation program for multiple expansion Stirling machines

    International Nuclear Information System (INIS)

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

    1992-01-01

    Multiple expansion Stirling machines have been a topic of interest at the University of Calgary for some years. Recently a second-order computer simulation program with integral graphics package for Stirling cryocoolers with up to four stages of expansion were developed and made available to the Stirling community. Adaptation of the program to multiple expansion Stirling power systems is anticipated. This paper briefly introduces the program and presents a specimen result

  18. Active Vibration Reduction of the Advanced Stirling Convertor

    Science.gov (United States)

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

    2016-01-01

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

  19. Operating single quantum emitters with a compact Stirling cryocooler.

    Science.gov (United States)

    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) 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.

  20. Operating single quantum emitters with a compact Stirling cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Schlehahn, A.; Krüger, L.; Gschrey, M.; Schulze, J.-H.; Rodt, S.; Strittmatter, A.; Heindel, T., E-mail: tobias.heindel@tu-berlin.de; Reitzenstein, S. [Institute of Solid State Physics, Technische Universität Berlin, 10623 Berlin (Germany)

    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.

  1. Integration of a wood pellet burner and a Stirling engine to produce residential heat and power

    International Nuclear Information System (INIS)

    Cardozo, Evelyn; Erlich, Catharina; Malmquist, Anders; Alejo, Lucio

    2014-01-01

    The integration a Stirling engine with a pellet burner is a promising alternative to produce heat and power for residential use. In this context, this study is focused on the experimental evaluation of the integration of a 20 kW th wood pellet burner and a 1 kW e Stirling engine. The thermal power not absorbed by the engine is used to produce hot water. The evaluation highlights the effects of pellet type, combustion chamber length and cycling operation on the Stirling engine temperatures and thermal power absorbed. The results show that the position of the Stirling engine is highly relevant in order to utilize as much as possible of the radiative heat from the burner. Within this study, only a 5 cm distance change between the Stirling engine and the pellet burner could result in an increase of almost 100 °C in the hot side of the engine. However, at a larger distance, the temperature of the hot side is almost unchanged suggesting dominating convective heat transfer from the hot flue gas. Ash accumulation decreases the temperature of the hot side of the engine after some cycles of operation when a commercial pellet burner is integrated. The temperature ratio, which is the relation between the minimum and maximum temperatures of the engine, decreases when using Ø8 mm wood pellets in comparison to Ø6 mm pellets due to higher measured temperatures on the hot side of the engine. Therefore, the amount of heat supplied to the engine is increased for Ø8 mm wood pellets. The effectiveness of the engine regenerator is increased at higher pressures. The relation between temperature of the hot side end and thermal power absorbed by the Stirling engine is nearly linear between 500 °C and 660 °C. Higher pressure inside the Stirling engine has a positive effect on the thermal power output. Both the chemical and thermal losses increase somewhat when integrating a Stirling engine in comparison to a stand-alone boiler for only heat production. The overall efficiency

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

    Science.gov (United States)

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

    2016-01-01

    procedures. This paper presents the design of the VCHP and its test results with a Stirling convertor at Glenn. Tests were carried for multiple on and off cycles to demonstrate repeatability. The impacts associated with the addition of the VCHP to the system are also addressed in terms of mass and additional heat losses due to the presence of the VCHP.

  3. Análisis de irreversibilidades en el comportamiento de un motor Stirling // Analysis of irreversibilities on performance of a Stirling engine

    Directory of Open Access Journals (Sweden)

    Juan José González-Bayón

    2011-05-01

    Full Text Available El objetivo de este estudio es determinar el efecto de las irreversibilidades (internas y externasdebidas a la transferencia de calor y las pérdidas de presión debidas a la fricción sobre elrendimiento de Segunda Ley de un motor Stirling de tipo considerando el volumen muerto. Elmotor Stirling es analizado usando un modelo matemático basado en las leyes de la termodinámicapara procesos con una velocidad finita. Se asume un modelo isotérmico de motor con volúmenes deespacio muerto en la zona caliente, zona fría y en el regenerador. Los resultados obtenidos muestranque a pesar de que teóricamente el motor Stirling posee un rendimiento igual al de Carnot, en lapráctica su rendimiento puede ser de 2 a 5 veces menor que éste, dependiendo de la eficiencia delregenerador, del volumen muerto, de la diferencia de temperatura entre fluido y focos térmicos y delas rpm a que se opere el motor.Palabras claves: motor Stirling, motor térmico regenerativo, análisis de irreversibilidades.____________________________________________________________________AbstractThe study aims to determine the effect of the internal and external irreversibilities caused by heattransfer and pressure losses due to friction on the Second Law performance of a Stirling engine tipewith death volume include. The Stirling engine is analyzed using a mathematical model based onthe laws of thermodynamics for processes with finite speed. It is assumed an isothermic model of themotor with death volume on hot zone, cold zone and regenerator. The results of this study show thatthe real cycle efficiency of the Sirling engine is approximately 2 to 5 times minor than the efficiency ofCarnot cycle as function of the regenerator efficiency, death volume, temperature difference betweenfluid and termic source and motor speed.Key words: stirling engine, regenerative heat engine, irreversibilities analysis.

  4. Optimization design and performance analysis of a miniature stirling engine

    Science.gov (United States)

    You, Zhanping; Yang, Bo; Pan, Lisheng; Hao, Changsheng

    2017-10-01

    Under given operation conditions, a stirling engine of 2 kW is designed which takes hydrogen as working medium. Through establishment of adiabatic model, the ways are achieved about performance improving. The ways are raising the temperature of hot terminal, lowering the temperature of cold end, increasing the average cycle pressure, speeding up the speed, phase angle being 90°, stroke volume ratio approximating to 1 and increasing the performance of regenerator.

  5. Thermochemical reactivity of 5–15 mol% Fe, Co, Ni, Mn-doped cerium oxides in two-step water-splitting cycle for solar hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Gokon, Nobuyuki, E-mail: ngokon@eng.niigata-u.ac.jp [Center for Transdisciplinary Research, Niigata University, 8050 Ikarashi 2-nocho, Nishi-ku, Niigata 950-2181 (Japan); Suda, Toshinori [Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2-nocho, Niigata 950-2181 (Japan); Kodama, Tatsuya [Department of Chemistry & Chemical Engineering, Faculty of Engineering, Niigata University, 8050 Ikarashi 2-nocho, Niigata 950-2181 (Japan)

    2015-10-10

    Highlights: • 5–15 mol% M-doped ceria are examined for thermochemical two-step water-splitting. • 5 mol% Fe- and Co-doped ceria have stoichiometric production of oxygen and hydrogen. • 10–15 mol% Fe- and Mn-doped ceria showed near-stoichiometric production. - Abstract: The thermochemical two-step water-splitting cycle using transition element-doped cerium oxide (M–CeO{sub 2−δ}; M = Fe, Co, Ni, Mn) powders was studied for hydrogen production from water. The oxygen/hydrogen productivity and repeatability of M–CeO{sub 2−δ} materials with M doping contents in the 5–15 mol% range were examined using a thermal reduction (TR) temperature of 1500 °C and water decomposition (WD) temperatures in the 800–1150 °C range. The temperature, steam partial pressure, and steam flow rate in the WD step had an impact on the hydrogen productivity and production rate. 5 mol% Fe- and Co-doped CeO{sub 2−δ} enhances hydrogen productivity by up to 25% on average compared to undoped CeO{sub 2}, and shows stable repeatability of stoichiometric oxygen and hydrogen production for the cyclic thermochemical two-step water-splitting reaction. In addition, 5 mol% Mn-doped CeO{sub 2−δ}, 10 and 15 mol% Fe- and Mn-doped CeO{sub 2−δ} show near stoichiometric reactivities.

  6. Trade-Offs between Energy Saving and Reliability in Low Duty Cycle Wireless Sensor Networks Using a Packet Splitting Forwarding Technique

    Directory of Open Access Journals (Sweden)

    Leonardi Alessandro

    2010-01-01

    Full Text Available One of the challenging topics and design constraints in Wireless Sensor Networks (WSNs is the reduction of energy consumption because, in most application scenarios, replacement of power resources in sensor devices might be unfeasible. In order to minimize the power consumption, some nodes can be put to sleep during idle times and wake up only when needed. Although it seems the best way to limit the consumption of energy, other performance parameters such as network reliability have to be considered. In a recent paper, we introduced a new forwarding algorithm for WSNs based on a simple splitting procedure able to increase the network lifetime. The forwarding technique is based on the Chinese Remainder Theorem and exhibits very good results in terms of energy efficiency and complexity. In this paper, we intend to investigate a trade-off between energy efficiency and reliability of the proposed forwarding scheme when duty-cycling techniques are considered too.

  7. Innovation at Stirling

    Science.gov (United States)

    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. Stirling engine with pressurized crankcase

    Science.gov (United States)

    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.

  9. Free-Piston Stirling Engines

    Science.gov (United States)

    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.

  10. Optimum performance characteristics of a solar-driven Stirling heat engine system

    International Nuclear Information System (INIS)

    Liao, Tianjun; Lin, Jian

    2015-01-01

    Graphical abstract: T–S diagram of the SHE cycle. - Highlights: • Based on Lagrange multiplier method, the optimal performance are investigated. • The energy balance between the absorber and the hot side of Stirling heat engine is considered. • The effects of major parameters on the optimal performance are investigated. - Abstract: A solar-driven Stirling heat engine system composed of a Stirling heat engine, a solar collector, and a heat sink is presented, in which the radiation and convection heat losses of the solar collector, the heat-leak between the thermal absorber and heat sink, the regenerative losses of the Stirling heat engine, and the energy balance between the thermal absorber and the high isothermal process of the Stirling heat engine are taken into consideration. Based on the irreversible thermodynamics and Lagrange multiplier method, the maximum power output and the corresponding optimal efficiency of the system are determined and the absorber temperature that maximizes the optimal system efficiency is calculated numerically. The influences of some system parameters such as the concentrating ratio, the volume ratio during the regenerative processes and irreversibilities of heat exchange processes on the optimal efficiency are analyzed in details. The results obtained here may provide a new idea to design practical solar-driven Stirling heat engine system

  11. Thermodynamic analysis of SOFC (solid oxide fuel cell)–Stirling hybrid plants using alternative fuels

    International Nuclear Information System (INIS)

    Rokni, Masoud

    2013-01-01

    A novel hybrid power system (∼10 kW) for an average family home is proposed. The system investigated contains a solid oxide fuel cell (SOFC) on top of a Stirling engine. The off-gases produced in the SOFC cycle are fed to a bottoming Stirling engine, at which additional power is generated. Simulations of the proposed system were conducted using different fuels, which should facilitate the use of a variety of fuels depending on availability. Here, the results for natural gas (NG), ammonia, di-methyl ether (DME), methanol and ethanol are presented and analyzed. The system behavior is further investigated by comparing the effects of key factors, such as the utilization factor and the operating conditions under which these fuels are used. Moreover, the effect of using a methanator on the plant efficiency is also studied. The combined system improves the overall electrical efficiency relative to that of a stand-alone Stirling engine or SOFC plant. For the combined SOFC and Stirling configuration, the overall power production was increased by approximately 10% compared to that of a stand-alone SOFC plant. System efficiencies of approximately 60% are achieved, which is remarkable for such small plant sizes. Additionally, heat is also produced to heat the family home when necessary. - Highlights: • Integrating a solid oxide fuel with a Stirling engine • Design of multi-fuel hybrid plants • Plants running on alternative fuels; natural gas, methanol, ethanol, DME and ammonia • Thermodynamic analysis of hybrid SOFC–Stirling engine plants

  12. Coupling of copper-chloride hybrid thermochemical water splitting cycle with a desalination plant for hydrogen production from nuclear energy

    International Nuclear Information System (INIS)

    Orhan, Mehmet F.; Dincer, Ibrahim; Naterer, Greg F.; Rosen, Marc A.

    2010-01-01

    Energy and environmental concerns have motivated research on clean energy resources. Nuclear energy has the potential to provide a significant share of energy supply without contributing to environmental emissions and climate change. Nuclear energy has been used mainly for electric power generation, but hydrogen production via thermochemical water decomposition provides another pathway for the utilization of nuclear thermal energy. One option for nuclear-based hydrogen production via thermochemical water decomposition uses a copper-chloride (Cu-Cl) cycle. Another societal concern relates to supplies of fresh water. Thus, to avoid causing one problem while solving another, hydrogen could be produced from seawater rather than limited fresh water sources. In this study we analyze a coupling of the Cu-Cl cycle with a desalination plant for hydrogen production from nuclear energy and seawater. Desalination technologies are reviewed comprehensively to determine the most appropriate option for the Cu-Cl cycle and a thermodynamic analysis and several parametric studies of this coupled system are presented for various configurations. (author)

  13. Mitigation of climate change via a copper-chlorine hybrid thermochemical water splitting cycle for hydrogen production from nuclear energy

    International Nuclear Information System (INIS)

    Orhan, M.F.; Dincer, I.; Rosen, M.A.

    2009-01-01

    Concerns regarding climate change have motivated research on clean energy resources. While many energy resources have limitations, nuclear energy has the potential to supply a significant share of energy supply without contributing to climate change. Nuclear energy has been used mainly for electric power generation, but hydrogen production via thermochemical water decomposition provides another option for the utilization of nuclear thermal energy. This paper describes nuclear-based hydrogen production technologies and discusses the role of the Cu-Cl cycle for thermochemical water decomposition, potentially driven in part by waste heat from a nuclear generating station, in reducing greenhouse gas emissions. (author)

  14. Multidimensional computer simulation of Stirling cycle engines

    Science.gov (United States)

    Hall, Charles A.; Porsching, Thomas A.

    1992-01-01

    This report summarizes the activities performed under NASA-Grant NAG3-1097 during 1991. During that period, work centered on the following tasks: (1) to investigate more effective solvers for ALGAE; (2) to modify the plotting package for ALGAE; and (3) to validate ALGAE by simulating oscillating flow problems similar to those studied by Kurzweg and Ibrahim.

  15. Optimal power and efficiency of quantum Stirling heat engines

    Science.gov (United States)

    Yin, Yong; Chen, Lingen; Wu, Feng

    2017-01-01

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

  16. Thermodynamic analysis of a Stirling engine including regenerator dead volume

    Energy Technology Data Exchange (ETDEWEB)

    Puech, Pascal; Tishkova, Victoria [Universite de Toulouse, UPS, CNRS, CEMES, 29 rue Jeanne Marvig, F-31055 Toulouse (France)

    2011-02-15

    This paper provides a theoretical investigation on the thermodynamic analysis of a Stirling engine with linear and sinusoidal variations of the volume. The regenerator in a Stirling engine is an internal heat exchanger allowing to reach high efficiency. We used an isothermal model to analyse the net work and the heat stored in the regenerator during a complete cycle. We show that the engine efficiency with perfect regeneration doesn't depend on the regenerator dead volume but this dead volume strongly amplifies the imperfect regeneration effect. An analytical expression to estimate the improvement due to the regenerator has been proposed including the combined effects of dead volume and imperfect regeneration. This could be used at the very preliminary stage of the engine design process. (author)

  17. A parametric investigation on a solar dish-Stirling system

    Science.gov (United States)

    Gholamalizadeh, Ehsan; Chung, Jae Dong

    2018-06-01

    The aim of this study is to analyze the performance of a solar dish-Stirling system. A mathematical model for the overall thermal efficiency of the solar-powered high-temperature-differential dish-Stirling engine is described. This model takes into account pressure losses due to fluid friction which is internal to the engine, mechanical friction between the moving parts, actual heat transfer includes the effects of both internal and external irreversibilities of the cycle and finite regeneration processes time. Validation was done through comparison with the actual power output of the "EuroDish" system. Moreover, the effects of dish diameter and working fluid on the performance of the system were studied. An increase of about 7.2% was observed for the power output using hydrogen as the working fluid rather than helium. Also, the focal distance for any diameter of dish was calculated.

  18. Stirling micro cogeneration unit for single-family houses. Compact and assembly-friendly; Stirling-Mikro-BHKW fuer den Einsatz im Einfamilienhaus. Kompakt und montagefreundlich

    Energy Technology Data Exchange (ETDEWEB)

    Gimsa, Andreas [Enerlyt Technik GmbH, Potsdam (Germany)

    2010-07-01

    Enerlyt of Potsdam is a manufacturer working on a micro cogeneration unit based on a Stirling engine whose thermodynamic cycle has lower losses, e.g. by making the expansion pistons bigger than the compression pistons. The unit can be operated with various fuels. The author describes the function and state of development of the unit. (orig.)

  19. Automotive Stirling Engine Development Program

    Science.gov (United States)

    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.

  20. Mathematical modeling of the Stirling engine in terms of applying the composition of the power complex containing non-conventional and renewable energy

    Science.gov (United States)

    Gaponenko, A. M.; Kagramanova, A. A.

    2017-11-01

    The opportunity of application of Stirling engine with non-conventional and renewable sources of energy. The advantage of such use. The resulting expression for the thermal efficiency of the Stirling engine. It is shown that the work per cycle is proportional to the quantity of matter, and hence the pressure of the working fluid, the temperature difference and, to a lesser extent, depends on the expansion coefficient; efficiency of ideal Stirling cycle coincides with the efficiency of an ideal engine working on the Carnot cycle, which distinguishes a Stirling cycle from the cycles of Otto and Diesel underlying engine. It has been established that the four input parameters, the only parameter which can be easily changed during operation, and which effectively affects the operation of the engine is the phase difference. Dependence of work per cycle of the phase difference, called the phase characteristic, visually illustrates mode of operation of Stirling engine. The mathematical model of the cycle of Schmidt and the analysis of operation of Stirling engine in the approach of Schmidt with the aid of numerical analysis. To conduct numerical experiments designed program feature in the language MathLab. The results of numerical experiments are illustrated by graphical charts.

  1. Free-piston Stirling technology for space power

    Science.gov (United States)

    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.

  2. Automotive Stirling engine development program: A success

    Science.gov (United States)

    Tabata, W. K.

    1987-01-01

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

  3. Demonstration Experiments with a Stirling Engine.

    Science.gov (United States)

    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)

  4. CHP from Updraft Gasifier and Stirling Engine

    DEFF Research Database (Denmark)

    Jensen, N.; Werling, J.; Carlsen, Henrik

    2002-01-01

    The combination of thermal gasification with a Stirling engine is an interesting concept for use in small combined heat and power plants based on biomass. By combining the two technologies a synergism can potentially be achieved. Technical problems, e.g. gas cleaning and fouling of the Stirling...... engine heat exchanger, can be eliminated and the overall electric efficiency of the system can be improved. At the Technical University of Denmark a Stirling engine fueled by gasification gas has been developed. In this engine the combustion system and the geometry of the hot heat exchanger...... of the Stirling engine has been adapted to the use of a gas with a low specific energy content and a high content of tar and particles. In the spring of 2001 a demonstration plant has been built in the western part of Denmark where this Stirling engine is combined with an updraft gasifier. A mathematical...

  5. Downsizing assessment of automotive Stirling engines

    Science.gov (United States)

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

    International Nuclear Information System (INIS)

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

    1992-06-01

    This report describes work performed by Mechanical Technology Incorporated (MTI) under NASA Contract NAS3-26061, open-quotes A Feasibility Assessment of Magnetic Bearings for Free-Piston Stirling Space Engines.close quotes The work was performed over the period from July 1990 through August 1991. The objective of the effort 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 future long-term space missions

  7. Multi-objective optimization of GPU3 Stirling engine using third order analysis

    International Nuclear Information System (INIS)

    Toghyani, Somayeh; Kasaeian, Alibakhsh; Hashemabadi, Seyyed Hasan; Salimi, Morteza

    2014-01-01

    Highlights: • A third-order analysis is carried out for optimization of Stirling engine. • The triple-optimization is done on a GPU3 Stirling engine. • A multi-objective optimization is carried out for a Stirling engine. • The results are compared with an experimental previous work for checking the model improvement. • The methods of TOPSIS, Fuzzy, and LINMAP are compared with each other in aspect of optimization. - Abstract: Stirling engine is an external combustion engine that uses any external heat source to generate mechanical power which operates at closed cycles. These engines are good choices for using in power generation systems; because these engines present a reasonable theoretical efficiency which can be closer to the Carnot efficiency, comparing with other reciprocating thermal engines. Hence, many studies have been conducted on Stirling engines and the third order thermodynamic analysis is one of them. In this study, multi-objective optimization with four decision variables including the temperature of heat source, stroke, mean effective pressure, and the engine frequency were applied in order to increase the efficiency and output power and reduce the pressure drop. Three decision-making procedures were applied to optimize the answers from the results. At last, the applied methods were compared with the results obtained of one experimental work and a good agreement was observed

  8. Free-Piston Stirling Convertor Controller Development at NASA Glenn Research Center

    Science.gov (United States)

    Regan, Timothy

    2004-01-01

    The free-piston Stirling convertor end-to-end modeling effort at NASA Glenn Research Center (GRC) 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, linear alternator, controller, and load. This paper is concerned with controllers. It discusses three controllers that have been studied using this model. Case motion has been added to the model recently so that effects of differences between convertor components can be simulated and ameliorative control engineering techniques can be developed. One concern when applying a system comprised of interconnected mass-spring-damper components is to prevent operation in any but the intended mode. The design mode is the only desired mode of operation, but all other modes are considered in controller design.

  9. An experimental study for the phase shift between piston and displacer in the Stirling cryocooler

    Energy Technology Data Exchange (ETDEWEB)

    Park, S. J.; Hong, Y. J.; Kim, H. B. [Korea Institute of Machinery and Materials, Taejon (Korea, Republic of); Son, H. K.; Yu, B. K. [Wooyoung Co., Ltd., Seoul (Korea, Republic of)

    2002-07-01

    The small cryocooler is being widely applied to the areas of infrared detector, superconductor filter, satellite communication, and cryopump. The cryocooler working on the Stirling cycle are characterized by small size, lightweight, low power consumption and high reliability. For these reasons, FPFD (Free Piston Free Displacer) Stirling cryocooler is widely used not only tactical infrared imaging camera but also medical diagnostic apparatus. In this study, Stirling cryocooler actuated by the dual linear motor is designed and manufactured. And, displacement of the piston is measured by LVDTs (Linear Variable Differential Transformers), displacement of the displacer is measured by laser optic method, and phase shift between piston and displacer is discussed. Finally, when the phase shift between displacements of the piston and displacer is 45 .deg., operating frequency is optimum and is decided by resonant frequency of the expander, mass and cross section area of the displacer and constant by friction and flow resistance.

  10. An experimental study for the phase shift between piston and displacer in the Stirling cryocooler

    International Nuclear Information System (INIS)

    Park, S. J.; Hong, Y. J.; Kim, H. B.; Son, H. K.; Yu, B. K.

    2002-01-01

    The small cryocooler is being widely applied to the areas of infrared detector, superconductor filter, satellite communication, and cryopump. The cryocooler working on the Stirling cycle are characterized by small size, lightweight, low power consumption and high reliability. For these reasons, FPFD (Free Piston Free Displacer) Stirling cryocooler is widely used not only tactical infrared imaging camera but also medical diagnostic apparatus. In this study, Stirling cryocooler actuated by the dual linear motor is designed and manufactured. And, displacement of the piston is measured by LVDTs (Linear Variable Differential Transformers), displacement of the displacer is measured by laser optic method, and phase shift between piston and displacer is discussed. Finally, when the phase shift between displacements of the piston and displacer is 45 .deg., operating frequency is optimum and is decided by resonant frequency of the expander, mass and cross section area of the displacer and constant by friction and flow resistance

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

    International Nuclear Information System (INIS)

    Slaby, J.G.

    1987-01-01

    An overview is presented of the National Aeronautics and Space Administration (NASA) Lewis Research Center (LeRC) free-piston Stirling engine activities directed toward space-power application. Free-piston Stirling technology is applicable for both solar and nuclear powered systems. As such, the NASA Lewis Research Center serves as the project office to manage the newly initiated SP-100 Advanced Technology program. This program provides the technology push for providing significant component and subsystem options for increased efficiency, reliability and survivability, and power output growth at reduced specific mass. One of the major elements of the program is the development of advanced power conversion of which the Stirling cycle is a viable candidate. Under this program the status of the 25 kWe opposed-piston Space Power Demonstrator Engine (SPDE) is presented. Included in the SPDE discussion are initial differences between predicted and experimental power outputs and power output influenced by variations in regenerators

  12. Novel separation process of gaseous mixture of SO2 and O2 with ionic liquid for hydrogen production in thermochemical sulfur-iodine water splitting cycle

    International Nuclear Information System (INIS)

    Kim, Chang Soo; Gong, Gyeong Taek; Yoo, Kye Sang; Kim, Honggon; Lee, Byoung Gwon; Ahn, Byoung Sung; Jung, Kwang Deog; Lee, Ki Yong; Song, Kwang Ho

    2007-01-01

    Sulfur-Iodine cycle is the most promising thermochemical cycle for water splitting to produce hydrogen which can replace the fossil fuels in the future. As a sub-cycle in the thermochemical Sulfur-Iodine water splitting cycle, sulfuric acid (H 2 SO 4 ) decomposes into oxygen (O 2 ) and sulfur dioxide (SO 2 ) which should be separated for the recycle of SO 2 into the sulfuric acid generation reaction (Bunsen Reaction). In this study, absorption and desorption process of SO 2 by ionic liquid which is useful for the recycle of SO 2 into sulfuric acid generation reaction after sulfuric acid decomposition in the thermochemical Sulfur-Iodine cycle is investigated. At first, the operability as an absorbent for the SO 2 absorption and desorption at high temperature without the volatilization of absorbents which is not suitable for the recycle of absorbent-free SO 2 after the absorption process. The temperature range of operability is determined by TGA and DTA analysis. Most of ionic liquids investigated are applicable at high temperature desorption without volatility around 300 deg. C except [BMIm] Cl, and [BMIm] OAc which show the decomposition of ionic liquids. To evaluate the capability of SO 2 absorption, each ionic liquid is located in the absorption tube and gaseous SO 2 is bubbled into the ionic liquid. During the bubbling, the weight of the system is measured and converted into the absorbed SO 2 amount at each temperature controlled by the heater. Saturated amounts of absorbed SO 2 by ionic liquids at 50 deg. C are presented. The effect of anions for the SO 2 absorption capability is shown in the order of Cl, OAc, MeSO 3 , BF 4 , MeSO 4 , PF 6 , and HSO 4 when they are combined with [BMIm] cation. [BMIm]Cl has the largest amount of SO 2 absorbed which can be the most promising absorbent; however, from the point of operability at high temperature which includes desorption process, [BMIm]Cl is vulnerable to high temperature around 250 deg. C based on the TGA

  13. The Stirling engine mechanism optimization

    Directory of Open Access Journals (Sweden)

    Jiří Podešva

    2016-03-01

    Full Text Available A special type of the gas engine with external combustion is called Stirling engine. The mechanism has two pistons with two volumes inside. The pistons are connected together through cooler, regenerator and warmer. The engine effectivity depends on the piston movement behaviour. The usual sinusoidal time curve leads to low effectiveness. The quick movement from lower to upper position with a certain delay in both top and bottom dead centres is more effective. The paper deals with three types of mechanisms, analyzing the piston movement, and their behavior. Special emphasize is taken to the piston movement regime.

  14. A nonproprietary, nonsecret program for calculating Stirling cryocoolers

    Science.gov (United States)

    Martini, W. R.

    1985-01-01

    A design program for an integrated Stirling cycle cryocooler was written on an IBM-PC computer. The program is easy to use and shows the trends and itemizes the losses. The calculated results were compared with some measured performance values. The program predicts somewhat optimistic performance and needs to be calibrated more with experimental measurements. Adding a multiplier to the friction factor can bring the calculated rsults in line with the limited test results so far available. The program is offered as a good framework on which to build a truly useful design program for all types of cryocoolers.

  15. Free-piston Stirling component test power converter test results and potential Stirling applications

    Science.gov (United States)

    Dochat, G. R.

    1992-01-01

    As the principal contractor to NASA-Lewis Research Center, Mechanical Technology Incorporated is under contract to develop free-piston Stirling power converters in the context of the competitive multiyear Space Stirling Technology Program. The first generation Stirling power converter, the component test power converter (CTPC) initiated cold end testing in 1991, with hot testing scheduled for summer of 1992. This paper reviews the test progress of the CTPC and discusses the potential of Stirling technology for various potential missions at given point designs of 250 watts, 2500 watts, and 25,000 watts.

  16. Numerical simulation for the design analysis of kinematic Stirling engines

    International Nuclear Information System (INIS)

    Araoz, Joseph A.; Salomon, Marianne; Alejo, Lucio; Fransson, Torsten H.

    2015-01-01

    Highlights: • A thermodynamic analysis for kinematic Stirling engines was presented. • The analysis integrated thermal, mechanical and thermodynamic interactions. • The analyses considered geometrical and operational parameters. • The results allowed to map the performance of the engine. • The analysis allow the design assessment of Stirling engines. - Abstract: The Stirling engine is a closed-cycle regenerative system that presents good theoretical properties. These include a high thermodynamic efficiency, low emissions levels thanks to a controlled external heat source, and multi-fuel capability among others. However, the performance of actual prototypes largely differs from the mentioned theoretical potential. Actual engine prototypes present low electrical power outputs and high energy losses. These are mainly attributed to the complex interaction between the different components of the engine, and the challenging heat transfer and fluid dynamics requirements. Furthermore, the integration of the engine into decentralized energy systems such as the Combined Heat and Power systems (CHP) entails additional complications. These has increased the need for engineering tools that could assess design improvements, considering a broader range of parameters that would influence the engine performance when integrated within overall systems. Following this trend, the current work aimed to implement an analysis that could integrate the thermodynamics, and the thermal and mechanical interactions that influence the performance of kinematic Stirling engines. In particular for their use in Combined Heat and Power systems. The mentioned analysis was applied for the study of an engine prototype that presented very low experimental performance. The numerical methodology was selected for the identification of possible causes that limited the performance. This analysis is based on a second order Stirling engine model that was previously developed and validated. The

  17. Variable displacement alpha-type Stirling engine

    Science.gov (United States)

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

    2016-08-01

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

  18. Advanced Stirling Convertor Testing at GRC

    Science.gov (United States)

    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. Multi-objective optimization of Stirling engine systems using Front-based Yin-Yang-Pair Optimization

    International Nuclear Information System (INIS)

    Punnathanam, Varun; Kotecha, Prakash

    2017-01-01

    Highlights: • Efficient multi-objective optimization algorithm F-YYPO demonstrated. • Three Stirling engine applications with a total of eight cases. • Improvements in the objective function values of up to 30%. • Superior to the popularly used gamultiobj of MATLAB. • F-YYPO has extremely low time complexity. - Abstract: In this work, we demonstrate the performance of Front-based Yin-Yang-Pair Optimization (F-YYPO) to solve multi-objective problems related to Stirling engine systems. The performance of F-YYPO is compared with that of (i) a recently proposed multi-objective optimization algorithm (Multi-Objective Grey Wolf Optimizer) and (ii) an algorithm popularly employed in literature due to its easy accessibility (MATLAB’s inbuilt multi-objective Genetic Algorithm function: gamultiobj). We consider three Stirling engine based optimization problems: (i) the solar-dish Stirling engine system which considers objectives of output power, thermal efficiency and rate of entropy generation; (ii) Stirling engine thermal model which considers the associated irreversibility of the cycle with objectives of output power, thermal efficiency and pressure drop; and finally (iii) an experimentally validated polytropic finite speed thermodynamics based Stirling engine model also with objectives of output power and pressure drop. We observe F-YYPO to be significantly more effective as compared to its competitors in solving the problems, while requiring only a fraction of the computational time required by the other algorithms.

  20. Automotive Stirling Engine Development Project

    Science.gov (United States)

    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. Splitting Descartes

    DEFF Research Database (Denmark)

    Schilhab, Theresa

    2007-01-01

    Kognition og Pædagogik vol. 48:10-18. 2003 Short description : The cognitivistic paradigm and Descartes' view of embodied knowledge. Abstract: That the philosopher Descartes separated the mind from the body is hardly news: He did it so effectively that his name is forever tied to that division....... But what exactly is Descartes' point? How does the Kartesian split hold up to recent biologically based learning theories?...

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

    Science.gov (United States)

    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.

  3. Raytheon Stirling/pulse Tube Cryocooler Development

    Science.gov (United States)

    Kirkconnell, C. S.; Hon, R. C.; Kesler, C. H.; Roberts, T.

    2008-03-01

    The first generation flight-design Stirling/pulse tube "hybrid" two-stage cryocooler has entered initial performance and environmental testing. The status and early results of the testing are presented. Numerous improvements have been implemented as compared to the preceding brassboard versions to improve performance, extend life, and enhance launch survivability. This has largely been accomplished by incorporating successful flight-design features from the Raytheon Stirling one-stage cryocooler product line. These design improvements are described. In parallel with these mechanical cryocooler development efforts, a third generation electronics module is being developed that will support hybrid Stirling/pulse tube and Stirling cryocoolers. Improvements relative to the second generation design relate to improved radiation hardness, reduced parts count, and improved vibration cancellation capability. Progress on the electronics is also presented.

  4. Stirling convertor performance mapping test results

    Science.gov (United States)

    Qiu, Songgang; Peterson, Allen A.; White, Maurice A.; Faultersack, Franklyn; Redinger, Darin L.; Petersen, Stephen L.

    2002-01-01

    The Department of Energy (DOE) has selected Free-Piston Stirling Convertors as a technology for future advanced radioisotope space power systems. In August 2000, DOE awarded competitive Phase I, Stirling Radioisotope Generator (SRG) power system integration contracts to three major aerospace contractors, resulting in SRG conceptual designs in February 2001. All three contractors based their designs on the Technology Demonstration Convertor (TDC) developed by Stirling Technology Company (STC) for DOE. The contract award to a single system integration contractor for Phases II and III of the SRG program is anticipated in late 2001. The first potential SRG mission is targeted for a Mars rover. Recent TDC performance data are provided in this paper, together with predictions from Stirling simulation models. .

  5. Simple and Clear Proofs of Stirling's Formula

    Science.gov (United States)

    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.

  6. Advanced Stirling Radioisotope Generator Life Certification Plan

    Science.gov (United States)

    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.

  7. Recent Stirling engine loss - understanding results

    International Nuclear Information System (INIS)

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

    1994-01-01

    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

  8. Scaling laws for free piston Stirling engine design: Benefits and challenges of miniaturization

    International Nuclear Information System (INIS)

    Formosa, Fabien; Fréchette, Luc G.

    2013-01-01

    This work explores the scaling effects for FPSE (free piston Stirling engines), which are known for their simple architecture and potentially high thermodynamic performances. Scaling laws are given and their potential for miniaturization is highlighted. A simple model which allows the design of the geometrical parameters of the heat exchangers, the regenerator and the masses of the pistons is proposed. It is based on the definition of six characteristic dimensionless groups. They are derived from the physics underlying the behavior of the free piston Stirling machine and their relevancy is backed up by comparisons between documented Stirling engines from the literature. Keeping constant values for each group throughout the scaling range theoretically ensures constant performance. The main losses of Stirling engine (heat conduction loss, reheat loss in the regenerator, pressure drop and gas-spring hysteresis) can be expressed as a function of the geometrical and operating parameters. Additionally, the consequences of leakage due to the manufacturing precision of pistons architectures are underlined. From the proposed scaling laws, potential power and efficiency of Stirling cycle engines at a millimeter scale can be anticipated. It appears that the power density increases with miniaturization. It is also shown that the dynamic masses related to the engine size are increased when scaling down and that the gap leakage presents the highest detrimental effects on the efficiency. These results call for dedicated architectures for micro-engines. - Highlights: • Similitude strategy is applied to Stirling engines and allows preliminary design. • New scaling laws are derived. • The power density can be increased with miniaturization. • The gap between the piston and casing is highly detrimental to the performances. • High engine operating pressure is required when miniaturizing

  9. Self-pressurizing Stirling engine

    Science.gov (United States)

    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.

  10. Stirling Engine Dynamic System Modeling

    Science.gov (United States)

    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.

  11. Improving Free-Piston Stirling Engine Specific Power

    Science.gov (United States)

    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.

  12. Screening of High Temperature Organic Materials for Future Stirling Convertors

    Science.gov (United States)

    Shin, Euy-sik E.; Scheiman, Daniel A.

    2017-01-01

    Along with major advancement of Stirling-based convertors, high temperature organics are needed to develop future higher temperature convertors for much improved efficiencies as well as to improve the margin of reliability for the current SOA (State-of-the-Art) convertors. The higher temperature capabilities would improve robustness of the convertors and also allow them to be used in additional missions, particularly ones that require a Venus flyby for a gravity assist. Various organic materials have been employed as essential components in the convertor for their unique properties and functions such as bonding, potting, sealing, thread locking, insulation, and lubrication. The Stirling convertor radioisotope generators have been developed for potential future space applications including Lunar/Mars surface power or a variety of spacecraft and vehicles, especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration. Thus, performance, durability, and reliability of the organics should be critically evaluated in terms of every possible material structure-process-service environment relations based on the potential mission specifications. The initial efforts in screening the high temperature candidates focused on the most susceptible organics, such as adhesive, potting compound, O-ring, shrink tubing, and thread locker materials in conjunction with commercially available materials. More systematic and practical test methodologies that were developed and optimized based on the extensive organic evaluations and validations performed for various Stirling convertor types were employed to determine thermal stability, outgassing, and material compatibility of the selected organic candidates against their functional requirements. Processing and fabrication conditions and procedures were also optimized. This report presents results of the three-step candidate evaluation processes, their application limitations, and the final selection

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

    Science.gov (United States)

    Meer, David W.; Oriti, Salvatore M.

    2012-01-01

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

  14. Magnetic bearings for free-piston Stirling engines

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Oriti, Salvatore M.

    2013-01-01

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

  16. James Stirling Regionalismo y modernidad

    Directory of Open Access Journals (Sweden)

    Javier de Esteban Garbayo

    2015-05-01

    Full Text Available ResumenEn los años treinta, la arquitectura moderna se había introducido en los más remotos lugares del mundo enfrentándose con la infinita idiosincrasia de lo local, y al mismo tiempo, el arquitecto, sintiendo las limitaciones de su estilo e intentando ampliar su vocabulario, se embarcó en un proceso de difusión, asimilación y personalización.La idea de una renovada época después de la posguerra británica, sería compartida por una joven generación de arquitectos con el fin de encontrar una nueva forma de modernidad.Si en sus proyectos domésticos de mediados de los cincuenta, James Stirling partió de una aproximación al regionalismo y a la 'tradición funcional' con el fin de renovar el lenguaje moderno, no abandonaría la idea 'programática' inicial de entender la arquitectura desde una consistencia formal y una lógica que combinaba 'una síntesis común del pasado reciente y una certera actitud hacia el futuro'. AbstractThirties, modern architecture had percolated into remote corners of the world, encountering the infinite idiosyncrasies of locality, and, at the same time, Architects, feelings the limitations of their style and becoming intent upon extending their vocabulary, embarked upon a process of diffusion, assimilation and personalitation.The idea of a renewed period after British postwar, was shared for a new young architects generationto find a new way of modernity.While in his mid fifties housing projects, James Stirling approached to 'regionalism' and 'the functional tradition' to renew the modern language, he wouldn't reject the programmatic idea to understand architecture from a logic and formal consistency that combine 'a common synthesis of the recent past and a certain attitude toward the future'.

  17. Variations on the Zilch Cycle

    Science.gov (United States)

    Binder, P.-M.; Tanoue, C. K. S.

    2013-01-01

    Thermo dynamic cycles in introductory physics courses are usually made up from a small number of permutations of isothermal, adiabatic, and constant-pressure and volume quasistatic strokes, with the working fluid usually being an ideal gas. Among them we find the Carnot, Stirling, Otto, Diesel, and Joule-Brayton cycles; in more advanced courses,…

  18. Combining solid biomass combustion and stirling technology

    Energy Technology Data Exchange (ETDEWEB)

    Siemers, W.; Senkel, N. [CUTEC-Institut GmbH, Clausthal-Zellerfeld (Germany)], e-mail: werner.siemers@cutec.de

    2012-11-01

    Decentralised electricity production in combination with and based on biomass still finds some difficulties in real applications. One concept favoured in a recent project is the connection of a wood chip furmace with a Stirling engine. Because the direct exposure of the Stirling head causes numerous problems, the solution is sought in designing an indirect heat transfer system. The main challenge is the temperature level, which should be reached for high electrical efficiencies. Temperatures above 1000 deg C at the biomass combustion side are needed for an efficient heat transfer at some 850 deg C at the Stirling engine in theory. Measurements on both installations have been conducted and analyzed. After this, the design phase is started. However, no final choice on the design has been taken.

  19. Advanced radioisotope heat source for Stirling Engines

    International Nuclear Information System (INIS)

    Dobry, T.J.; Walberg, G.

    2001-01-01

    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

  20. Cost estimating Brayton and Stirling engines

    Science.gov (United States)

    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.

  1. Stirling Technology Development at NASA GRC

    Science.gov (United States)

    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

  2. Stirling Technology Development at NASA GRC. Revised

    Science.gov (United States)

    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

  3. Stirling technology development at NASA GRC

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    1991-10-01

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

  5. Free piston space Stirling technology program

    Science.gov (United States)

    Dochat, G. R.; Dhar, M.

    1989-01-01

    MTI recently completed an initial technology feasibility program for NASA by designing, fabricating and testing a space power demonstrator engine (SPDE). This program, which confirms the potential of free-piston Stirling engines, provided the major impetus to initiate a free-piston Stirling space engine (SSE) technology program. The accomplishments of the SPDE program are reviewed, and an overview of the SSE technology program and technical status to date is provided. It is shown that progress in both programs continues to justify its potential for either nuclear or solar space power missions.

  6. Evaluation of thermal efficiency and energy conversion of thermoacoustic Stirling engines

    International Nuclear Information System (INIS)

    Zhong Junhu; Zheng Yuli; Qing Li; Qiang Li

    2010-01-01

    Thermodynamic cycle transferring heat and work was executed in thermoacoustic engines, when the acoustic resonators substituted the moving mechanical components of the traditional heat engines. Based on the traveling-wave phasing and reversible heat transfer, thermoacoustic Stirling engines could achieve 70% of the Carnot efficiency theoretically, if the inevitable viscous dissipation in resonators was also counted as exported power. It should be pointed out an error on this efficiency evaluation in the previous literatures. More than 70% of the acoustic power production was often consumed by the side-branch resonator that was the essential configuration to build up a thermoacoustic Stirling engine. According to the simulation results and some experimental data, the actual available acoustic power consumed by the acoustic loads was restricted by the operating peak-to-mean pressure ratio, i.e. |p 1 /p m |. When the peak-to-mean pressure ratio operated on 4-6.5%, the thermal efficiency and power density of the available acoustic power reached higher levels. But the available acoustic power would approach zero when |p 1 /p m | attained 10%. It was approved that the turbulence oscillation occurred on the higher |p 1 /p m | (usually >4%) was the main reason of the excess dissipation in the side-branch resonator. This character of the available power limited the wide application of thermoacoustic Stirling engines. The evaluation of thermal efficiency and energy conversion also indicated the improving direction of thermoacoustic Stirling engines. Generators driven by the thermoacoustic Stirling engines were an effective way, due to the elimination of the side-branch resonator. To achieve a high power density and a high pressure ratio on the higher available power efficiency level, the standing-wave thermoacoustic engines might outvie the traveling-wave thermoacoustic engines. To enjoy the best features of standing-wave engines and traveling-wave engines simultaneously

  7. Modeling the dynamic and thermodynamic operation of Stirling engines by means of an equivalent electrical circuit

    International Nuclear Information System (INIS)

    Cascella, Franco; Sorin, Mikhail; Formosa, Fabien; Teyssedou, Alberto

    2017-01-01

    Highlights: • A model based on the electrical analogy theory has been developed to predict the operation of a Stirling engine. • The models takes into account the continuity, the momentum and the energy conservation equations. • The model predicts the operating conditions of the RE100 Free piston Stirling engine. • The model is sensible to the modeling of the effects of the machine load. - Abstract: The Stirling engines are inherently efficient; their thermodynamic cycles reach the Carnot efficiency. These technologies are suitable to operate under any low temperature difference between the hot and the cold sources. For these reasons, these engines can be considered as reliable power conversion systems to promote the conversion of low-grade waste heat generated by industrial plants. The need of a model to predict the behavior of these engines is of primary importance. Nevertheless, a great difficulty is encountered in developing such a model since it is not simple to take into account coupled thermodynamic and dynamic effects. This is the main reason why several models make use of electrical analogies to describe Stirling engines (in particular, free-piston machines): by assuming the pressure equivalent to a voltage and the flow rate to an electrical current, a coupled dynamic-thermodynamic analysis of the engine can be performed. In this paper, an electrical circuit whose behavior is equivalent to that of the engine is derived from the electrical analogy theory. To this aim, we propose an electrical analogy model based on the three conservation laws (mass, momentum and energy). Since limited experimental information is available in the open literature, the results obtained with the proposed model are compared with the experimental data collected at the NASA Lewis Research center for a free-piston Stirling engine i.e., the RE-1000 engine.

  8. Performance analysis of different working gases for concentrated solar gas engines: Stirling & Brayton

    International Nuclear Information System (INIS)

    Sharaf Eldean, Mohamed A.; Rafi, Khwaja M.; Soliman, A.M.

    2017-01-01

    Highlights: • Different working gases are used to power on Concentrated Solar Gas Engines. • Gases are used to increase the system efficiency. • Specific heat capacity is considered a vital role for the comparison. • Brayton engine resulted higher design limits. • CO 2 is favorable as a working gas more than C 2 H 2 . - Abstract: This article presents a performance study of using different working fluids (gases) to power on Concentrated Solar Gas Engine (CSGE-Stirling and/or Brayton). Different working gases such as Monatomic (five types), Diatomic (three types) and Polyatomic (four types) are used in this investigation. The survey purported to increase the solar gas engine efficiency hence; decreasing the price of the output power. The effect of using different working gases is noticed on the engine volume, dish area, total plant area, efficiency, compression and pressure ratios thence; the Total Plant Cost (TPC, $). The results reveal that the top cycle temperature effect is reflected on the cycle by increasing the total plant efficiency (2–10%) for Brayton operational case and 5–25% for Stirling operational case. Moreover; Brayton engine resulted higher design limits against the Stirling related to total plant area, m 2 and TPC, $ while generating 1–100 MW e as an economic case study plant. C 2 H 2 achieved remarkable results however, CO 2 is considered for both cycles operation putting in consideration the gas flammability and safety issues.

  9. Nonlinear dynamics analysis of a low-temperature-differential kinematic Stirling heat engine

    Science.gov (United States)

    Izumida, Yuki

    2018-03-01

    The low-temperature-differential (LTD) Stirling heat engine technology constitutes one of the important sustainable energy technologies. The basic question of how the rotational motion of the LTD Stirling heat engine is maintained or lost based on the temperature difference is thus a practically and physically important problem that needs to be clearly understood. Here, we approach this problem by proposing and investigating a minimal nonlinear dynamic model of an LTD kinematic Stirling heat engine. Our model is described as a driven nonlinear pendulum where the motive force is the temperature difference. The rotational state and the stationary state of the engine are described as a stable limit cycle and a stable fixed point of the dynamical equations, respectively. These two states coexist under a sufficient temperature difference, whereas the stable limit cycle does not exist under a temperature difference that is too small. Using a nonlinear bifurcation analysis, we show that the disappearance of the stable limit cycle occurs via a homoclinic bifurcation, with the temperature difference being the bifurcation parameter.

  10. Two Quantum Polytropic Cycles

    Science.gov (United States)

    Arias-Hernández, L. A.; Morales-Serrano, A. F.

    2002-11-01

    In this work we follow the Bender et al paper [1] to study the quantum analogues of the Stirling and Ericsson polytropic cycles. In the context of the classical thermodynamics, the Stirling and Ericsson cycles correspond to reversible heat engines with two isothermal processes joined by two polytropic branches which occur in a device called regenerator. If this device is an ideal one, the efficiency of these cycles is the Carnot efficiency. Here, we introduce the quantum analogues of the Stirling and Ericsson cycles, the first one based on a double square potential well with a finite potential barrier, since in this system the tunnel effect could be the analogue to the regeneration classical process, therefore the isochoric quantum branches would really correspond to an internal energy storage, and the last one with an unknown system where the isobaric quantum processes don't induce changes in its quantum state. With these systems the quantum engines have cycles consisting of polytropic and isothermal quantum processes analogues to the corresponding classical processes. We show that in both cases the quantum cycles have an efficiency given by ηCQM = 1 - EC/EH, which is the same expression for the quantum analogue of the Carnot cycle studied by Bender.

  11. Double acting stirling engine piston ring

    Science.gov (United States)

    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.

  12. Two piston V-type Stirling engine

    Science.gov (United States)

    Corey, John A.

    1987-01-01

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

  13. Experimental research on the Stirling engine

    Science.gov (United States)

    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.

  14. Piston rod seal for a Stirling engine

    Science.gov (United States)

    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.

  15. Quirks of Stirling's Approximation

    Science.gov (United States)

    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…

  16. The Stirling Lesson-Sampling Instruments.

    Science.gov (United States)

    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…

  17. Exergy Analysis and Optimization of an Alpha Type Stirling Engine Using the Implicit Filtering Algorithm

    Directory of Open Access Journals (Sweden)

    James A. Wills

    2017-12-01

    Full Text Available This paper presents the exergy analysis and optimization of the Stirling engine, which has enormous potential for use in the renewable energy industry as it is quiet, efficient, and can operate with a variety of different heat sources and, therefore, has multi-fuel capabilities. This work aims to present a method that can be used by a Stirling engine designer to quickly and efficiently find near-optimal or optimal Stirling engine geometry and operating conditions. The model applies the exergy analysis methodology to the ideal-adiabatic Stirling engine model. In the past, this analysis technique has only been applied to highly idealized Stirling cycle models and this study shows its use in the realm of Stirling cycle optimization when applied to a more complex model. The implicit filtering optimization algorithm is used to optimize the engine as it quickly and efficiently computes the optimal geometry and operating frequency that gives maximum net-work output at a fixed energy input. A numerical example of a 1,000 cm3 engine is presented, where the geometry and operating frequency of the engine are optimized for four different regenerator mesh types, varying heater inlet temperature and a fixed energy input of 15 kW. The WN200 mesh is seen to perform best of the four mesh types analyzed, giving the greatest net-work output and efficiency. The optimal values of several different engine parameters are presented in the work. It is shown that the net-work output and efficiency increase with increasing heater inlet temperature. The optimal dead-volume ratio, swept volume ratio, operating frequency, and phase angle are all shown to decrease with increasing heater inlet temperature. In terms of the heat exchanger geometry, the heater and cooler tubes are seen to decrease in size and the cooler and heater effectiveness is seen to decrease with increasing heater temperature, whereas the regenerator is seen to increase in size and effectiveness. In

  18. A thermodynamic study for the optimization of stable operation of free piston Stirling engines

    Energy Technology Data Exchange (ETDEWEB)

    Rogdakis, E.D.; Bormpilas, N.A.; Koniakos, I.K. [National Technical Univerisity, Athens (Greece). Dept. of Mechanical Engineering

    2004-03-01

    One of the most novel applications of the Stirling cycle is in the free piston configuration that was initially designed by W. Beale. In free piston Stirling engines (FPSEs), there are no mechanical linkages coupling the pistons or displacers, the motions of the reciprocating components follow the working gas pressure variations. Fillipo de Monte and G. Benvenuto have recently proposed a linearization technique of the dynamic balance equations. The aim of this paper is to predict the thermodynamic conditions for stable operation of FPSEs and their modeling. The equations of the angular velocity are solved analytically in terms of the working gas mass and the displacer-piston phase angle of the machine. Using the criterion of stable engine cyclic steady operation, a mathematically rigorous form is obtained for the main parameters of the engine. Furthermore, for simplicity reasons, thermodynamic magnitudes are obtained using the Schmidt analysis (isothermal model). (author)

  19. A thermodynamic study for the optimization of stable operation of free piston Stirling engines

    International Nuclear Information System (INIS)

    Rogdakis, E.D.; Bormpilas, N.A.; Koniakos, I.K.

    2004-01-01

    One of the most novel applications of the Stirling cycle is in the free piston configuration that was initially designed by W. Beale. In free piston Stirling engines (FPSEs), there are no mechanical linkages coupling the pistons or displacers, the motions of the reciprocating components follow the working gas pressure variations. Fillipo de Monte and G. Benvenuto have recently proposed a linearization technique of the dynamic balance equations. The aim of this paper is to predict the thermodynamic conditions for stable operation of FPSEs and their modeling. The equations of the angular velocity are solved analytically in terms of the working gas mass and the displacer-piston phase angle of the machine. Using the criterion of stable engine cyclic steady operation, a mathematically rigorous form is obtained for the main parameters of the engine. Furthermore, for simplicity reasons, thermodynamic magnitudes are obtained using the Schmidt analysis (isothermal model)

  20. Heat-transfer aspects of Stirling power generation using incinerator waste energy

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, S.T.; Lin, F.Y.; Chiou, J.S. [National Cheng Kung University, Tainan, Taiwan (China). Department of Mechanical Engineering

    2003-01-01

    The integration of a free-piston Stirling engine with linear alternator and an incinerator is able to effectively recover the waste energy and generate electrical power. In this study, a cycle-averaged heat transfer model is employed to investigate the performance of a free-piston Stirling engine installed on an incinerator. With the input of source and sink temperatures and other realistic heat transfer coefficients, the efficiency and the optimal power output are estimated, and the effect induced by internal and external irreversibilities is also evaluated. The proposed approach and modeling results presented in this study provide valuable information for engineers and designers to recover energy from small-scale incinerators. (author)

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

    Science.gov (United States)

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

    1983-01-01

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

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

    Science.gov (United States)

    Shin, Euy-Sik Eugene

    2015-01-01

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

  3. THE STIRLING GAS REFRIGERATING MACHINE MECHANICAL DESIGN IMPROVING

    Directory of Open Access Journals (Sweden)

    V. V. Trandafilov

    2016-06-01

    Full Text Available To improve the mechanical design of the piston Stirling gas refrigeration machine the structural optimization of rotary vane Stirling gas refrigeration machine is carried out. This paper presents the results of theoretical research. Analysis and prospects of rotary vane Stirling gas refrigeration machine for domestic and industrial refrigeration purpose are represented. The results of a patent search by mechanisms of transformation of rotary vane machines are discussed.

  4. THE STIRLING GAS REFRIGERATING MACHINE MECHANICAL DESIGN IMPROVING

    Directory of Open Access Journals (Sweden)

    V. V. Trandafilov

    2016-02-01

    Full Text Available To improve the mechanical design of the piston Stirling gas refrigeration machine the structural optimization of rotary vane Stirling gas refrigeration machine is carried out. This paper presents the results of theoretical research. Analysis and prospects of rotary vane Stirling gas refrigeration machine for domestic and industrial refrigeration purpose are represented. The results of a patent search by mechanisms of transformation of rotary vane machines are discussed

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

    Science.gov (United States)

    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.

  6. Vibration-free stirling cryocooler for high definition microscopy

    Science.gov (United States)

    Riabzev, S. V.; Veprik, A. M.; Vilenchik, H. S.; Pundak, N.; Castiel, E.

    2009-12-01

    The normal operation of high definition Scanning Electronic and Helium Ion microscope tools often relies on maintaining particular components at cryogenic temperatures. This has traditionally been accomplished by using liquid coolants such as liquid Nitrogen. This inherently limits the useful temperature range to above 77 K, produces various operational hazards and typically involves elevated ownership costs, inconvenient logistics and maintenance. Mechanical coolers, over-performing the above traditional method and capable of delivering required (even below 77 K) cooling to the above cooled components, have been well-known elsewhere for many years, but their typical drawbacks, such as high purchasing cost, cooler size, low reliability and high power consumption have so far prevented their wide-spreading. Additional critical drawback is inevitable degradation of imagery performance originated from the wideband vibration export as typical for the operation of the mechanical cooler incorporating numerous movable components. Recent advances in the development of reliable, compact, reasonably priced and dynamically quiet linear cryogenic coolers gave rise to so-called "dry cooling" technologies aimed at eventually replacing the traditional use of outdated liquid Nitrogen cooling facilities. Although much improved these newer cryogenic coolers still produce relatively high vibration export which makes them incompatible with modern high definition microscopy tools. This has motivated further research activity towards developing a vibration free closed-cycle mechanical cryocooler. The authors have successfully adapted the standard low vibration Stirling cryogenic refrigerator (Ricor model K535-LV) delivering 5 W@40 K heat lift for use in vibration-sensitive high definition microscopy. This has been achieved by using passive mechanical counterbalancing of the main portion of the low frequency vibration export in combination with an active feed-forward multi

  7. Stirling Energy Module (SEM) as Micro-CHP; Stirling Energy Module (SEM) als Mini-BHKW

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, A.

    2006-07-01

    Since many years, a lot of effort is being put into the development of combined heat and power units (CHP) for the decentralised production of electric power. For long time, the main focus was on fuel cells. In the meantime, the Stirling technology, which is based upon classical mechanical engineering and innovative technical concepts, proceeded in its development as well. The following article describes the technology and the actual state of the development of the Stirling Energy Module (SEM) for the application as Micro-CHP in one-family-houses. SEM is based on a free-piston engine with a linear power generator, producing electric power while heating. The Stirling engine is planned the be introduced into the market as a replacement for the conventional heating systems within a couple of years. (author)

  8. Composite Matrix Regenerator for Stirling Engines

    Science.gov (United States)

    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.

  9. Cermet Coatings for Solar Stirling Space Power

    Science.gov (United States)

    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.

  10. Stirling engine with air working fluid

    Science.gov (United States)

    Corey, John A.

    1985-01-01

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

  11. Stirling Engine With Radial Flow Heat Exchangers

    Science.gov (United States)

    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.

  12. Reliability Issues in Stirling Radioisotope Power Systems

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Meer, David W.; Lewandowski, Edward J.

    2010-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  15. Tests Of A Stirling-Engine Power Converter

    Science.gov (United States)

    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.

  16. Modeling for Control of a Wobble–Yoke Stirling Engine

    NARCIS (Netherlands)

    García–Canseco, Eloísa; Scherpen, Jacquelien M.A.; Kuindersma, Marnix

    2009-01-01

    In this paper we derive the dynamic model of a four–cylinder double–acting wobble–yoke Stirling engine. In contrast with the classical thermodynamics methods that dominate the literature of Stirling mechanisms, we present a control system perspective to obtain a useful model for the analysis and

  17. Modeling for Control of a Wobble-Yoke Stirling Engine

    NARCIS (Netherlands)

    Garcia Canseco, E.; Scherpen, J.M.A.; Kuindersma, M.

    2009-01-01

    In this paper we derive the dynamical model of a four–cylinder double–acting wobble–yoke Stirling engine introduced originally by [1, 2]. In contrast with the classical thermodynamics methods that dominate the literature of Stirling mechanisms, we present a control systems perspective to obtain a

  18. On-Board Hydrogen Gas Production System For Stirling Engines

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Diver, R.B.; Menicucci, D.F. [Sandia National Labs., Albuquerque, NM (United States). Energy and Environment Div.

    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.

  20. Ross-Stirling engines: Variations on a theme

    Energy Technology Data Exchange (ETDEWEB)

    Walker, G; Fauvel, R

    1986-01-01

    A new mechanism called the Ross linkage offers the prospect for compact, lightweight, long-lived, relatively low-cost, Stirling engines with excellent prospects for early commercial developed for various applications. Ross-Stirling engines are unusually compact, with installation envelope about one-third of conventional engines, piston side forces are virtually eliminated facilitating the use of dry lubricated or close tolerance, gas lubricated seals and the linkage geometry automatically favors the large bore/short ratios preferred for Stirling engines. The linkage is simple to make with few moving parts so that cost is relatively low. Various potential or actual embodiments of Ross-Stirling engines are reviewed including Stirling-Stirling gas-fired heat pumps, multicylinder power systems and cryocoolers. The system has sufficient flexibility to readily accommodate widely disparate piston stroke and cylinder diameters. Most work has been done so far with two-piston Stirling engines but the same linkage may be adopted for piston-displacer Stirling engines. 6 refs., 10 figs.

  1. Stirling engines for biomass – what is the problem?

    DEFF Research Database (Denmark)

    Carlsen, Henrik

    2005-01-01

    The External combustion of the Stirling engine makes it very attractive for small-scale Combined Heat and Power (CHP) plants using bio-fuels. Especially wood chips are an attractive fuel because of the high melting point and the low content of ash. Unfortunately, it is more complicated than...... expected to use bio-fuels for a Stirling engine. The high temperature in the hot heat exchanger transferring heat from the combustion to the Stirling engine combined with the low heating value of the fuel reduce the obtainable efficiency of the plant. The limitations of the combustion temperature in order...... to avoid melted ash in the combustion chamber decrease the obtainable efficiency even further. If a Stirling engine, which has an efficiency of 28,5% using natural gas, is converted into utilization of bio-fuel, the efficiency will decrease to 17,5%. Another problem for utilization of bio-fuels in Stirling...

  2. A simple free-piston Sterling engine for combined heat and power generation (CHP) in the residential sector; Einfacher Stirling-Freikolben-Motor fuer die Kraft-Waerme-Kopplung (KWK) im Wohnbereich

    Energy Technology Data Exchange (ETDEWEB)

    Budliger, J.P.

    2001-07-01

    A completely static resonance tube is used in the Stirling cycle, as a substitute for a displacer piston. The Sterling system described works with only one, elastically suspended piston. The simple, cost-effective and maintenance-free basic design concept is explained in full detail, as well as some possible design types of resonance tube-charged, one-piston Stirling systems and their major advantages and performance characterisitcs. (orig./CB) [German] Anstelle eines Schwingkolbens kann auch ein voellig statisches Resonanzrohr eingesetzt werden: das resultierende Stirling-System umfasst nur noch einen einzigen, elastisch aufgehaengten Kolben. Dieses einfache, kostenguenstige und unterhaltsfreie Konzept stellt eine erwartungsvolle Loesung fuer dezentrale KWK-Anlagen dar. Im Vortrag werden einige moegliche Auslegungen solcher, mit Resonanzrohren aufgeladenen 1-Kolben-Stirling-Aggregate diskutiert, ihre wesentlichsten Eigenschaften und Leistungscharakteristiken beschrieben. (orig./CB)

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

    Science.gov (United States)

    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. Water-splitting-based, sustainable and efficient H2 production in green algae as achieved by substrate limitation of the Calvin-Benson-Bassham cycle.

    Science.gov (United States)

    Nagy, Valéria; Podmaniczki, Anna; Vidal-Meireles, André; Tengölics, Roland; Kovács, László; Rákhely, Gábor; Scoma, Alberto; Tóth, Szilvia Z

    2018-01-01

    Photobiological H 2 production has the potential of becoming a carbon-free renewable energy source, because upon the combustion of H 2 , only water is produced. The [Fe-Fe]-type hydrogenases of green algae are highly active, although extremely O 2 -sensitive. Sulphur deprivation is a common way to induce H 2 production, which, however, relies substantially on organic substrates and imposes a severe stress effect resulting in the degradation of the photosynthetic apparatus. We report on the establishment of an alternative H 2 production method by green algae that is based on a short anaerobic induction, keeping the Calvin-Benson-Bassham cycle inactive by substrate limitation and preserving hydrogenase activity by applying a simple catalyst to remove the evolved O 2 . Cultures remain photosynthetically active for several days, with the electrons feeding the hydrogenases mostly derived from water. The amount of H 2 produced is higher as compared to the sulphur-deprivation procedure and the process is photoautotrophic. Our protocol demonstrates that it is possible to sustainably use algal cells as whole-cell catalysts for H 2 production, which enables industrial application of algal biohydrogen production.

  5. Non-ideal Stirling engine thermodynamic model suitable for the integration into overall energy systems

    International Nuclear Information System (INIS)

    Araoz, Joseph A.; Salomon, Marianne; Alejo, Lucio; Fransson, Torsten H.

    2014-01-01

    The reliability of modelling and simulation of energy systems strongly depends on the prediction accuracy of each system component. This is the case of Stirling engine-based systems, where an accurate modelling of the engine performance is very important to understand the overall system behaviour. In this sense, many Stirling engine analyses with different approaches have been already developed. However, there is a lack of Stirling engine models suitable for the integration into overall system simulations. In this context, this paper aims to develop a rigorous Stirling engine model that could be easily integrated into combined heat and power schemes for the overall techno-economic analysis of these systems. The model developed considers a Stirling engine with adiabatic working spaces, isothermal heat exchangers, dead volumes, and imperfect regeneration. Additionally, it considers mechanical pumping losses due to friction, limited heat transfer and thermal losses on the heat exchangers. The model is suitable for different engine configurations (alpha beta and gamma engines). It was developed using Aspen Custom Modeller ® (ACM®) as modelling software. The set of equations were solved using ACM ® equation solver for steady-state operation. However, due to the dynamic behaviour of the cycle, a C++ code was integrated to solve iteratively a set of differential equations. This resulted in a cyclic steady-state model that calculates the power output and thermal requirements of the system. The predicted efficiency and power output were compared with the numerical model and the experimental work reported by the NASA Lewis Research Centre for the GPU-3 Stirling engine. This showed average absolute errors around ±4% for the brake power, and ±5% for the brake efficiency at different frequencies. However, the model also showed large errors (±15%) for these calculations at higher frequencies and low pressures. Additional results include the calculation of the cyclic

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

    Science.gov (United States)

    der Minassians, Artin

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

  7. Development and evaluation of a Stirling-powered cardiac assist system. Annual report, May 1974--Jul 1975

    International Nuclear Information System (INIS)

    Andrus, S.; Faeser, R.J.; Moise, J.; Hoffman, L.C.; Rudnicki, M.I.

    1975-09-01

    The Stirling-Cycle engine is designed to power implantable physiologically compatible heart-assist and total heart replacement devices. Heat is provided by a 238 Pu radioisotope capsule. Program activity during this report period included the development of the PAC-5 and PAC-5M actuators and the MK-VII engine. The report describes extensive endurance and accelerated life testing of complete LVAD systems and individual components

  8. Update on the NASA GRC Stirling Technology development project

    Science.gov (United States)

    Thieme, Lanny G.; Schreiber, Jeffrey G.

    2001-02-01

    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. The NASA Next Generation Stirling Technology Program Overview

    Science.gov (United States)

    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.

  10. Ecological optimization and parametric study of irreversible Stirling and Ericsson heat pumps

    International Nuclear Information System (INIS)

    Tyagi, S.K.; Kaushik, S.C.; Salohtra, R.

    2002-01-01

    This communication presents the ecological optimization and parametric study of irreversible Stirling and Ericsson heat pump cycles, in which the external irreversibility is due to finite temperature difference between working fluid and external reservoirs while the internal irreversibilities are due to regenerative heat loss and other entropy generations within the cycle. The ecological function is defined as the heating load minus the irreversibility (power loss) which is ambient temperature times the entropy generation. The ecological function is optimized with respect to working fluid temperatures, and the expressions for various parameters at the optimal operating condition are obtained. The effects of different operating parameters on the performance of these cycles have been studied. It is found that the effect of internal irreversibility parameter is more pronounced than the other parameters on the performance of these cycles. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-05-01

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

  12. Stability analysis of free piston Stirling engines

    Science.gov (United States)

    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.

  13. Double acting stirling engine phase control

    Science.gov (United States)

    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.

  14. A high performance thermoacoustic Stirling-engine

    Energy Technology Data Exchange (ETDEWEB)

    Tijani, M.E.H.; Spoelstra, S. [Energy research Centre of the Netherlands (ECN), PO Box 1, 1755 ZG Petten (Netherlands)

    2011-11-10

    In thermoacoustic systems heat is converted into acoustic energy and vice versa. These systems use inert gases as working medium and have no moving parts which makes the thermoacoustic technology a serious alternative to produce mechanical or electrical power, cooling power, and heating in a sustainable and environmentally friendly way. A thermoacoustic Stirling heat engine is designed and built which achieves a record performance of 49% of the Carnot efficiency. The design and performance of the engine is presented. The engine has no moving parts and is made up of few simple components.

  15. In-line stirling energy system

    Science.gov (United States)

    Backhaus, Scott N [Espanola, NM; Keolian, Robert [State College, PA

    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.

  16. Preliminary Results from Simulations of Temperature Fluctuations in Stirling Engine Regenerator Matrices

    DEFF Research Database (Denmark)

    Andersen, Stig Kildegård; Carlsen, Henrik; Thomsen, Per Grove

    2003-01-01

    The objective of this study has been to create a model for studying effects of temperature fluctuations in regenerator matrices on Stirling engine performance. A one-dimensional model with axial discretisation of engine components has been formulated using a fixed Eulerian grid. The model contains...... that adjusts solutions so that they satisfy the necessary cyclic boundary conditions as well as integral conditions for cyclic heat transfer for walls in the engine and for the mean cycle pressure. It has been found that it is possible to accurately solve the stiff ODE system that describes the coupled...

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

    Science.gov (United States)

    Reséndiz-Antonio, Margarita; Santillán, Moisés

    2014-09-01

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

  18. Initial testing of a variable-stroke Stirling engine

    Science.gov (United States)

    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.

  19. Linear hydraulic drive system for a Stirling engine

    Science.gov (United States)

    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.

  20. Loss terms in free-piston Stirling engine models

    Science.gov (United States)

    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.

  1. Thermoacoustic refrigerators and engines comprising cascading stirling thermodynamic units

    Science.gov (United States)

    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.

  2. Coded Splitting Tree Protocols

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Stefanovic, Cedomir; Popovski, Petar

    2013-01-01

    This paper presents a novel approach to multiple access control called coded splitting tree protocol. The approach builds on the known tree splitting protocols, code structure and successive interference cancellation (SIC). Several instances of the tree splitting protocol are initiated, each...... instance is terminated prematurely and subsequently iterated. The combined set of leaves from all the tree instances can then be viewed as a graph code, which is decodable using belief propagation. The main design problem is determining the order of splitting, which enables successful decoding as early...

  3. Economic performance of the SCE Stirling dish

    International Nuclear Information System (INIS)

    Stone, K.W.; Lopez, C.W.; McAlister, R.E.

    1993-01-01

    In 1982 McDonnell Douglas Aerospace Space System (MDA-SS) and United Stirling AB of Sweden formed a joint venture to develop and market a solar Stirling dish unit. Eight modules were built and extensively tested from 1984 to 1988. Power production and daily energy-conversion efficiency as determined by field testing have been characterized and modeled in a computer program. Included in this simulation are models of mirror soiling rate, wind spillage loss, mirror washing and other maintenance outage time, operation and maintenance (O and M) costs and other cost models. An economic model of a hybrid (combustion) receiver has been included in the simulation for illustrating the value of using solar energy when available and other fuels such as methane, natural gas, hydrogen, etc. when solar energy is not available or adequate. This paper describes the simulation and presents comparisons of the simulation to test data. The simulation also estimates both the O and M expenses and levelized energy costs for different production volumes

  4. Isotope powered Stirling generator for terrestrial applications

    International Nuclear Information System (INIS)

    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

  5. Economic performance of the SCE Stirling dish

    International Nuclear Information System (INIS)

    Stone, K.W.; Lopez, C.W.; McAlister, R.E.

    1995-01-01

    In 1982 McDonnell Douglas Aerospace (MDA) and United Stirling AB (USAB) of Sweden formed a joint venture to develop and market a solar Stirling dish system. Eight modules were built and extensively tested from 1984 to 1988. Power production and daily energy-conversion efficiency as determined by field testing were characterized and modeled into a computer program. Included in this simulation are models of mirror soiling rate, wind spillage loss, mirror washing, and other maintenance outage time, operation and maintenance (O and M) costs, and equipment purchase cost. An economic model of a hybrid (combustion) receiver has been included in the simulation for illustrating the value of using solar energy when available and other fuels such as methane, natural gas, hydrogen, etc. when solar energy is not available or adequate. This paper describes the simulation and presents comparisons of the simulation to test data. The simulation also estimates both the O and M expenses and levelized energy costs for different production volumes

  6. On Generalizations of the Stirling Number Triangles

    Science.gov (United States)

    Lang, Wolfdieter

    2000-09-01

    Sequences of generalized Stirling numbers of both kinds are introduced. These sequences of triangles (i.e. infinite-dimensional lower triangular matrices) of numbers will be denoted by S2(k;n,m) and S1(k;n,m) with k in Z. The original Stirling number triangles of the second and first kind arise when k = 1. S2(2;n,m) is identical with the unsigned S1(2;n,m) triangle, called S1p(2;n,m), which also represents the triangle of signless Lah numbers. Certain associated number triangles, denoted by s2(k;n,m) and s1(k;n,m), are also defined. Both s2(2;n,m) and s1(2;n + 1, m + 1) form Pascal's triangle, and s2(-1,n,m) turns out to be Catalan's triangle. Generating functions are given for the columns of these triangles. Each S2(k) and S1(k) matrix is an example of a Jabotinsky matrix. Therefore the generating functions for the rows of these triangular arrays constitute exponential convolution polynomials. The sequences of the row sums of these triangles are also considered. These triangles are related to the problem of obtaining finite transformations from infinitesimal ones generated by x^k d/dx, for k in Z.

  7. Preliminary SP-100/Stirling heat exchanger designs

    International Nuclear Information System (INIS)

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

    1994-01-01

    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

  8. 40 kW Stirling Engine for Solid Fuel

    DEFF Research Database (Denmark)

    Carlsen, Henrik; Trærup, Jens

    1996-01-01

    The external combustion in a Stirling engine makes it very attractive for utilisation of solid fuels in decentralised combined heat and power (CHP) plants. Only a few projects have concentrated on the development of Stirling engines specifically for biomass. In this project, a Stirling engine has...... been designed primarily for utilisation 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 pressurised crankcase so...

  9. Stirling engine alternatives for the terrestrial solar application

    Science.gov (United States)

    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.

  10. Optimal design of Stirling heat engine using an advanced ...

    Indian Academy of Sciences (India)

    R V Rao

    The comparisons of the proposed algorithm are made with those obtained by using the decision-making methods like linear ... cooling water and had improved the thermal efficiency of ... integrated system of a free-piston Stirling engine and an.

  11. Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

    Science.gov (United States)

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

    2014-01-01

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

  12. Integrated Stirling Convertor and Hall Thruster Test Conducted

    Science.gov (United States)

    Mason, Lee S.

    2002-01-01

    An important aspect of implementing Stirling Radioisotope Generators on future NASA missions is the integration of the generator and controller with potential spacecraft loads. Some recent studies have indicated that the combination of Stirling Radioisotope Generators and electric propulsion devices offer significant trip time and payload fraction benefits for deep space missions. A test was devised to begin to understand the interactions between Stirling generators and electric thrusters. An electrically heated RG- 350 (350-W output) Stirling convertor, designed and built by Stirling Technology Company of Kennewick, Washington, under a NASA Small Business Innovation Research agreement, was coupled to a 300-W SPT-50 Hall-effect thruster built for NASA by the Moscow Aviation Institute (RIAME). The RG-350 and the SPT-50 shown, were installed in adjacent vacuum chamber ports at NASA Glenn Research Center's Electric Propulsion Laboratory, Vacuum Facility 8. The Stirling electrical controller interfaced directly with the Hall thruster power-processing unit, both of which were located outside of the vacuum chamber. The power-processing unit accepted the 48 Vdc output from the Stirling controller and distributed the power to all the loads of the SPT-50, including the magnets, keeper, heater, and discharge. On February 28, 2001, the Glenn test team successfully operated the Hall-effect thruster with the Stirling convertor. This is the world's first known test of a dynamic power source with electric propulsion. The RG-350 successfully managed the transition from the purely resistive load bank within the Stirling controller to the highly capacitive power-processing unit load. At the time of the demonstration, the Stirling convertor was operating at a hot temperature of 530 C and a cold temperature of -6 C. The linear alternator was producing approximately 250 W at 109 Vac, while the power-processing unit was drawing 175 W at 48 Vdc. The majority of power was delivered to the

  13. A comparative reliability analysis of free-piston Stirling machines

    Science.gov (United States)

    Schreiber, Jeffrey G.

    2001-02-01

    A free-piston Stirling power convertor is being developed for use in an advanced radioisotope power system to provide electric power for NASA deep space missions. These missions are typically long lived, lasting for up to 14 years. The Department of Energy (DOE) is responsible for providing the radioisotope power system for the NASA missions, and has managed the development of the free-piston power convertor for this application. The NASA Glenn Research Center has been involved in the development of Stirling power conversion technology for over 25 years and is currently providing support to DOE. Due to the nature of the potential missions, long life and high reliability are important features for the power system. Substantial resources have been spent on the development of long life Stirling cryocoolers for space applications. As a very general statement, free-piston Stirling power convertors have many features in common with free-piston Stirling cryocoolers, however there are also significant differences. For example, designs exist for both power convertors and cryocoolers that use the flexure bearing support system to provide noncontacting operation of the close-clearance moving parts. This technology and the operating experience derived from one application may be readily applied to the other application. This similarity does not pertain in the case of outgassing and contamination. In the cryocooler, the contaminants normally condense in the critical heat exchangers and foul the performance. In the Stirling power convertor just the opposite is true as contaminants condense on non-critical surfaces. A methodology was recently published that provides a relative comparison of reliability, and is applicable to systems. The methodology has been applied to compare the reliability of a Stirling cryocooler relative to that of a free-piston Stirling power convertor. The reliability analysis indicates that the power convertor should be able to have superior reliability

  14. White Paper on Dish Stirling Technology: Path Toward Commercial Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Andraka, Charles E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Concentrating Solar Power Dept.; Stechel, Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Concentrating Solar Power Dept.; Becker, Peter [Stirling Energy Systems, Scottsdale, AZ (United States); Messick, Brian [Stirling Energy Systems, Scottsdale, AZ (United States)

    2016-07-01

    Dish Stirling energy systems have been developed for distributed and large-scale utility deployment. This report summarizes the state of the technology in a joint project between Stirling Energy Systems, Sandia National Laboratories, and the Department of Energy in 2011. It then lays out a feasible path to large scale deployment, including development needs and anticipated cost reduction paths that will make a viable deployment product.

  15. Normal ordering problem and the extensions of the Stirling grammar

    Science.gov (United States)

    Ma, S.-M.; Mansour, T.; Schork, M.

    2014-04-01

    The purpose of this paper is to investigate the connection between context-free grammars and normal ordered problem, and then to explore various extensions of the Stirling grammar. We present grammatical characterizations of several well known combinatorial sequences, including the generalized Stirling numbers of the second kind related to the normal ordered problem and the r-Dowling polynomials. Also, possible avenues for future research are described.

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

    Science.gov (United States)

    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

  17. Sodium Variable Conductance Heat Pipe for Radioisotope Stirling Systems

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  20. Feasibility Demonstration of a Multi-Cylinder Stirling Convertor with a Duplex Linear Alternator, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Stirling Technology Company (STC) proposes to integrate an existing Multi-Cylinder Free-Piston Stirling Engine (MPFPSE) with innovative compact linear alternators....

  1. Mathematical model of the Amazon Stirling engine

    Energy Technology Data Exchange (ETDEWEB)

    Vidal Medina, Juan Ricardo [Universidad Autonoma de Occidente (Colombia)], e-mail: jrvidal@uao.edu.co; Cobasa, Vladimir Melian; Silva, Electo [Universidade Federal de Itajuba, MG (Brazil)], e-mail: vlad@unifei.edu.br

    2010-07-01

    The Excellency Group in Thermoelectric and Distributed Generation (NEST, for its acronym in Portuguese) at the Federal University of Itajuba, has designed a Stirling engine prototype to provide electricity to isolated regions of Brazil. The engine was designed to operate with residual biomass from timber process. This paper presents mathematical models of heat exchangers (hot, cold and regenerator) integrated into second order adiabatic models. The general model takes into account the pressure drop losses, hysteresis and internal losses. The results of power output, engine efficiency, optimal velocity of the exhaust gases and the influence of dead volume in engine efficiency are presented in this paper. The objective of this modeling is to propose improvements to the manufactured engine design. (author)

  2. Stirling engine control mechanism and method

    Science.gov (United States)

    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.

  3. Solar Stirling for deep space applications

    International Nuclear Information System (INIS)

    Mason, Lee S.

    2000-01-01

    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 multihundred 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

  4. Creep rupture behavior of Stirling engine materials

    Science.gov (United States)

    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.

  5. Cermet coatings for solar Stirling space power

    International Nuclear Information System (INIS)

    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 convertor. The role of the cermet coating is to absorb as much of the incident solar energy as possible. The ability to mix metal and ceramic at the atomic level offers the opportunity to tailor the composition and the solar absorptance of these coatings. Several candidate cermet coatings were created and their solar absorptance was characterized as-manufactured and after exposure to elevated temperatures. Coating composition was purposely varied through the thickness of the coating. As a consequence of changing composition, islands of metal are thought to form in the ceramic matrix. Computer modeling indicated that diffusion of the metal atoms played an important role in island formation while the ceramic was important in locking the islands in place. Much of the solar spectrum is absorbed as it passes through this labyrinth

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

    Science.gov (United States)

    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

  7. Qualitative comparison of duplex Stirling and absorption refrigerators in domestic applications

    Energy Technology Data Exchange (ETDEWEB)

    Shao, H. [Global Cooling BV, Zutphen (Netherlands)

    2000-07-01

    A qualitative comparison has been carried out between the duplex Stirling and the absorption refrigerator for domestic applications. The duplex Stirling has many advantages over the absorption refrigerator on efficiency, modulation, suitability, operating costs, pollution reduction. Based on the state of the art of free-piston gas-bearing and linear-motor Stirling engines and coolers, it appears technically and economically feasible to develop the duplex Stirling to compete with the absorption refrigerator for heat-driven domestic refrigeration. (orig.)

  8. Market Structure and Stock Splits

    OpenAIRE

    David Michayluk; Paul Kofman

    2001-01-01

    Enhanced liquidity is one possible motivation for stock splits but empirical research frequently documents declines in liquidity following stock splits. Despite almost thirty years of inquiry, little is known about all the changes in a stock's trading activity following a stock split. We examine how liquidity measures change around more than 2,500 stock splits and find a pervasive decline in most measures. Large stock splits exhibit a more severe liquidity decline than small stock splits, esp...

  9. Concentric Split Flow Filter

    Science.gov (United States)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  10. Split Malcev algebras

    Indian Academy of Sciences (India)

    project of the Spanish Ministerio de Educación y Ciencia MTM2007-60333. References. [1] Calderón A J, On split Lie algebras with symmetric root systems, Proc. Indian. Acad. Sci (Math. Sci.) 118(2008) 351–356. [2] Calderón A J, On split Lie triple systems, Proc. Indian. Acad. Sci (Math. Sci.) 119(2009). 165–177.

  11. Stochastic split determinant algorithms

    International Nuclear Information System (INIS)

    Horvatha, Ivan

    2000-01-01

    I propose a large class of stochastic Markov processes associated with probability distributions analogous to that of lattice gauge theory with dynamical fermions. The construction incorporates the idea of approximate spectral split of the determinant through local loop action, and the idea of treating the infrared part of the split through explicit diagonalizations. I suggest that exact algorithms of practical relevance might be based on Markov processes so constructed

  12. Linear Dynamics and Control of a Kinematic Wobble–Yoke Stirling Engine

    NARCIS (Netherlands)

    Alvarez–Aguirre, Alejandro; García–Canseco, Eloísa; Scherpen, Jacquelien M.A.

    2010-01-01

    This paper presents a control systems approach for the modeling and control of a kinematic wobble–yoke Stirling engine. The linear dynamics of the Stirling engine are analyzed based on the dynamical model of the system, developed by these authors. We show that the Stirling engine can be viewed as a

  13. Linear dynamics and control of a kinematic wobble-yoke Stirling engine

    NARCIS (Netherlands)

    Alvarez Aguirre, A.; Garcia Canseco, E.; Scherpen, J.M.A.

    2010-01-01

    This paper presents a control systems approachfor the modeling and control of a kinematic wobbleyokeStirling engine. The linear dynamics of the Stirling engine are analyzed based on the dynamical model of the system, developed by the authors in [1]. We show that the Stirling engine can be viewed as

  14. The thermal non-equilibrium porous media modelling for CFD study of woven wire matrix of a Stirling regenerator

    International Nuclear Information System (INIS)

    Costa, S.C.; Barreno, I.; Tutar, M.; Esnaola, J.A.; Barrutia, H.

    2015-01-01

    Highlights: • A numerical procedure to derive porous media’s coefficients is proposed. • The local thermal non-equilibrium porous media model is more suitable for regenerators. • The regenerator temperature profiles can be better fitted to a logarithmic curve. • The wound woven wire matrix provides lower performance compared to stacked. • The numerical characterization methodology is useful for the multi-D Stirling engine models. - Abstract: Different numerical methods can be applied to the analysis of the flow through the Stirling engine regenerator. One growing approach is to model the regenerator as porous medium to simulate and design the full Stirling engine in three-dimensional (3-D) manner. In general, the friction resistance coefficients and heat transfer coefficient are experimentally obtained to describe the flow and thermal non-equilibrium through a porous medium. A finite volume method (FVM) based non-thermal equilibrium porous media modelling approach characterizing the fluid flow and heat transfer in a representative small detailed flow domain of the woven wire matrix is proposed here to obtain the porous media coefficients without further requirement of experimental studies. The results are considered to be equivalent to those obtained from the detailed woven wire matrix for the pressure drop and heat transfer. Once the equivalence between the models is verified, this approach is extended to model oscillating regeneration cycles through a full size regenerator porous media for two different woven wire matrix configurations of stacked and wound types. The results suggest that the numerical modelling approach proposed here can be applied with confidence to model the regenerator as a porous media in the multi-dimensional (multi-D) simulations of Stirling engines

  15. A CFD parametric study on the performance of a low-temperature-differential γ-type Stirling engine

    International Nuclear Information System (INIS)

    Chen, Wen-Lih; Yang, Yu-Ching; Salazar, Jose Leon

    2015-01-01

    Highlights: • A parametric study on a low-temperature-differential Stirling engine has been conducted by using CFD. • The effects of three geometric and two operational parameters on engine performance have been investigated. • It is found that each parameter produces different effects except power piston stroke and power piston radius. • The results are useful for guiding the design of new low-temperature-differential Stirling engines. - Abstract: An in-house CFD code has been applied to a low-temperature-differential (LTD) γ-type Stirling engine to understand the effects posed by several geometrical and operational parameters on engine performance. The results include variations of pressure, temperature, and heat transfer rates within an engine cycle as well as variations of engine’s power and efficiency versus these parameters. It is found that power piston stroke and radius influence engine performance very similarly, and power and efficiency both increase as these two parameters increase. In fact, the effects of the two parameters can be assimilated into those by the parameter of compression ratio. The stroke of displacer is observed to affect strongly on heat input but weakly on power, thus causing the efficiency to decrease as it increases. As expected, both power and efficiency increase as temperature difference between the hot and cold ends increases. Lastly, engine speed is observed to pose strong positive effects on power but exert weak effects on efficiency. This study reveals the effects produced by several important parameters on engine performance, and such information is very useful for the design of new LTD Stirling engines.

  16. A Stirling engine for use with lower quality fuels

    Science.gov (United States)

    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.

  17. Insoluble Coatings for Stirling Engine Heat Pipe Condenser Surfaces

    Science.gov (United States)

    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.

  18. Dynamic Analysis and Test Results for an STC Stirling Generator

    Science.gov (United States)

    Qiu, Songgang; Peterson, Allen A.

    2004-02-01

    Long-life, high-efficiency generators based on free-piston Stirling machines are a future energy-conversion solution for both space and commercial applications. To aid in design and system integration efforts, Stirling Technology Company (STC) has developed dynamic simulation models for the internal moving subassemblies and for complete Stirling convertor assemblies. These dynamic models have been validated using test data from operating prototypes. Simplified versions of these models are presented to help explain the operating characteristics of the Stirling convertor. Power spectrum analysis is presented for the test data for casing acceleration, piston motion, displacer motion, and controller current/voltage during full power operation. The harmonics of a Stirling convertor and its moving components are identified for the STC zener-diode control scheme. The dynamic behavior of each moving component and its contribution to the system dynamics and resultant vibration forces are discussed. Additionally, the effects of a passive balancer and external suspension are predicted by another simplified system model.

  19. Stirling based micro co-generation system for single households

    Energy Technology Data Exchange (ETDEWEB)

    Ribberink, J.S.; Zutt, J.G.M.; Rabou, L.P.L.M.; Beckers, G.J.J. [ECN Clean Fossil Fuels, Petten (Netherlands); Baijens, C.A.W.; Luttikholt, J.J.M. [ATAG Verwarming, Lichtenvoorde (Netherlands)

    2000-04-01

    This paper describes the progress made in the ENATEC development program for a free piston Stirling engine based micro co-generation system that serves the supply of up to 1 kW{sub e} and up to 24 kW heat for domestic heating and/or for hot tap water production for single households at overall system efficiencies of 96%. Experiments show that the free piston Stirling engines from Stirling Technology Company run very reliably and controllably, and that the efficiency targets for the 1 kW{sub e} micro co-generation system are feasible. A ceramic foam burner with good heat transfer characteristics and low NOx emissions was developed. A demonstration micro co-generation unit was built and successfully presented. A 1 kW{sub e} free piston Stirling engine for the European market was developed. High efficiencies at full load and at part load, low emissions, low noise, and minimum maintenance make the Stirling engine based micro co-generation system an attractive candidate for the next generation of domestic boilers in Europe. 5 refs.

  20. Optimization of powered Stirling heat engine with finite speed thermodynamics

    International Nuclear Information System (INIS)

    Ahmadi, Mohammad H.; Ahmadi, Mohammad Ali; Pourfayaz, Fathollah; Bidi, Mokhtar; Hosseinzade, Hadi; Feidt, Michel

    2016-01-01

    Highlights: • Based on finite speed method and direct method, the optimal performance is investigated. • The effects of major parameters on the optimal performance are investigated. • The accuracy of the results was compared with previous works. - Abstract: Popular thermodynamic analyses including finite time thermodynamic analysis was lately developed based upon external irreversibilities while internal irreversibilities such as friction, pressure drop and entropy generation were not considered. The aforementioned disadvantage reduces the reliability of the finite time thermodynamic analysis in the design of an accurate Stirling engine model. Consequently, the finite time thermodynamic analysis could not sufficiently satisfy researchers for implementing in design and optimization issues. In this study, finite speed thermodynamic analysis was employed instead of finite time thermodynamic analysis for studying Stirling heat engine. The finite speed thermodynamic analysis approach is based on the first law of thermodynamics for a closed system with finite speed and the direct method. The effects of heat source temperature, regenerating effectiveness, volumetric ratio, piston stroke as well as rotational speed are included in the analysis. Moreover, maximum output power in optimal rotational speed was calculated while pressure losses in the Stirling engine were systematically considered. The result reveals the accuracy and the reliability of the finite speed thermodynamic method in thermodynamic analysis of Stirling heat engine. The outcomes can help researchers in the design of an appropriate and efficient Stirling engine.

  1. Finite time thermodynamic analysis and optimization of solar-dish Stirling heat engine with regenerative losses

    Directory of Open Access Journals (Sweden)

    Sharma Arjun

    2011-01-01

    Full Text Available The present study investigates the performance of the solar-driven Stirling engine system to maximize the power output and thermal efficiency using the non-linearized heat loss model of the solar dish collector and the irreversible cycle model of the Stirling engine. Finite time thermodynamic analysis has been done for combined system to calculate the finite-rate heat transfer, internal heat losses in the regenerator, conductive thermal bridging losses and finite regeneration process time. The results indicate that exergy efficiency of dish system increases as the effectiveness of regenerator increases but decreases with increase in regenerative time coefficient. It is also found that optimal range of collector temperature and corresponding concentrating ratio are 1000 K~1400 K and 1100~1400, respectively in order to get maximum value of exergy efficiency. It is reported that the exergy efficiency of this dish system can reach the maximum value when operating temperature and concentrating ratio are 1150 K and 1300, respectively.

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

    Science.gov (United States)

    Intsiful, Peter; Mensah, Francis; Thorpe, Arthur

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

  3. MODELLING AND FAILURE ANALYSIS OF FLEXURE SPRINGS FOR A STIRLING CRYOCOOLER

    Directory of Open Access Journals (Sweden)

    RAJESH V. R.

    2017-04-01

    Full Text Available In the range of milliwatt to a few watts cooling capacity, Stirling cycle and pulse tube coolers are most suitable for producing cryogenic temperatures owing to their eco-friendliness, high efficiency, cooling capacity to mass ratio etc. The compressor of a Stirling cooler is powered by a linear motor. The power piston of the cooler is held in position and moves to and fro with the support of so called flexure springs or flexure bearings. Flexures avoid direct contact between moving parts of the compressor of the cooler. Thus, if designed adequately to withstand fatigue, flexure bearings can easily outlast rolling element bearings and slider bearings. In this work, a computational analysis is used to study the performance of flexure spring by varying the geometrical parameters. Three of the most common spring materials namely, SS304, beryllium copper and spring steel are considered for analysis. The analysis was made by varying the parameters like spiral sweep angle, slot width, number of spirals and disc thickness. The influence of each of these parameters on the fatigue life of the spring has been investigated. The results suggest that flexure springs of three spiral arms would be the ideal choice for the selected cryocooler. The variation of stress developed with respect to different design parameters and fatigue damage factor are presented graphically.

  4. Development of 1 kW Stirling cryocooler using a linear compressor

    International Nuclear Information System (INIS)

    Ko, J; Kim, H; Hong, Y J; Yeom, H; In, S; Park, S J

    2015-01-01

    Cryogenic cooling systems for HTS electric power devices require a reliable and efficient high-capacity cryocooler. A Striling cryocooler with a linear compressor can be a good candidate. It has advantages of low vibration and long maintenance cycle compared with a kinematic-driven Stirling cryocooler. In this study, we developed a dual-opposed linear compressor of 12 kW electric input power with two 6 kW linear motors. Electrical performance of the fabricated linear compressor is verified by experimental measurement of thrust constant. The developed Stirling cryocooler has a gamma-type configuration. The piston and displacer are supported with a flexure spring. A slit-type heat exchanger is adopted for the cold and warm-end, and the generated heat is rejected by cooling water. In the cooling performance test, waveforms of voltage, current, displacement and pressure are obtained and their amplitude and phase difference are analysed. The developed cryocooler reaches 47.8 K within 23.4 min. with no-load. Heat load tests shows a cooling capacity of 440 W at 78.1 K with 6.45 kW of electric input power and 19.4 of % Carnot COP. (paper)

  5. Use of biomass as fuel for Stirling motors; Uso de biomassa como combustivel para acionamento de motores Stirling

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Robledo Wakin; Aradas, Maria Eugenia Coria; Cobas, Vladmir Rafael Melian; Lora, Electo Eduardo Silva [Universidade Federal de Itajuba (UNIFEI), MG (Brazil). Inst. de Engenharia Mecanica. Nucleo de Estudos em Sistemas Termicos], e-mail: robledo@unifei.edu.br

    2004-07-01

    The search to increase the electrical generation, together with the need to decrease the pollution emission, has encouraged the alternative energy sources. Nowadays around the world there are a lot of alternative energy sources incentive programs. In Brazil have PROINFA - Alternative Energy Sources Incentive Program. An example of alternative energy sources is the use of biomass as combustible. In the electrical generation, the biomass can be used directly, having it's directly combustion, and transforming the thermal energy liberated in electrical energy, or can be transformed in gas or liquid, and after use technology as internal combustion engine and gas turbine to generate electricity with these combustibles. Few technologies can be used to generate electricity burning directly to the biomass. Among these technologies, have the Stirling engine. It is possible to use this engine because the Stirling engines are external combustion engines, and it has not contact between the work gas and the flue gas. In this way, the Stirling engine needs a heat source, independent of the combustible type that will be used, including solar source. In this work will be present this technology, the different kinds of Stirling engines according to their configuration, moreover will be present the ST 05 G Stirling engine, which is a 500 W engine, acquired by University Federal of Itajuba. Also are present the tests results of this engine, and the installation to work with wood waste as combustible. (author)

  6. Demonstration of a free piston Stirling engine driven linear alternator, phase I report

    International Nuclear Information System (INIS)

    Goldwater, B.; Piller, S.; Rauch, J.; Cella, A.

    1977-01-01

    The results of the work performed under Phase I of the free piston Stirling engine demonstrator program are described. The objective of the program is to develop a 2 kW free piston Stirling engine/linear alternator energy conversion system, for an isotopic heat source, with a greater than 30% overall efficiency. Phase I was a 15-month effort to demonstrate the feasibility of the system through analysis and experimental testing of the individual components. An introduction to Stirling engines and the details of the tasks completed are presented in five major sections: (1) introduction to Stirling engine; (2) preliminary design of an advanced free piston Stirling demonstrator engine; (3) design and test of a 1 kWE output linear alternator; (4) test of a model free piston Stirling engine; and (5) development of a free piston Stirling engine computer simulation code

  7. Demonstration of a free piston Stirling engine driven linear alternator, phase I report

    Energy Technology Data Exchange (ETDEWEB)

    Goldwater, B.; Piller, S.; Rauch, J.; Cella, A.

    1977-03-30

    The results of the work performed under Phase I of the free piston Stirling engine demonstrator program are described. The objective of the program is to develop a 2 kW free piston Stirling engine/linear alternator energy conversion system, for an isotopic heat source, with a greater than 30% overall efficiency. Phase I was a 15-month effort to demonstrate the feasibility of the system through analysis and experimental testing of the individual components. An introduction to Stirling engines and the details of the tasks completed are presented in five major sections: (1) introduction to Stirling engine; (2) preliminary design of an advanced free piston Stirling demonstrator engine; (3) design and test of a 1 kWE output linear alternator; (4) test of a model free piston Stirling engine; and (5) development of a free piston Stirling engine computer simulation code.

  8. Improving Power Density of Free-Piston Stirling Engines

    Science.gov (United States)

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

    2016-01-01

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

  9. Experimental study of the pressure characteristics in the Stirling refrigerator

    International Nuclear Information System (INIS)

    Hong, Yong Ju; Park, Seong Je; Kim, Hyo Bong; Koh, Deuk Yong

    2001-01-01

    The linear compressor have been widely used for pressure wave generation in the Stirling cryocooler and Stirling type pulse tube cryocooler for tactical purpose. The linear compressor has small and compact structure, and long life due to having non-contact sealing mechanism and the pressure drop through regenerator was ver important role in the motion of displacer in the expander of the Stirling cryocooler. In this study, the characteristic of the linear compressor and the pressure drop through regenerator in the expander was experimentally investigated. The results show resonance of the compressor is very important to get maximum performance and the gas spring force in the compression space of the compressor has effect on the characteristic of resonance and the results show the pressure drop through regenerator is very small than operating pressure change

  10. Micro power/heat cogeneration incorporating a stirling engine

    International Nuclear Information System (INIS)

    Luft, S.

    2003-01-01

    The Stirling-engine for CHP-purpose developed by SOLO is a trend-setting technology. It represents the most suspicious perspective apart from the fuel-cell technology in order to become suitable to the requirements of the future power supply in the focus of the sustainability and the decentralized energy supply. The charm of the Stirling technology is based on the external combustion: a so far not known variability with the primary energy choice as well as a life span substantially extending, wear-free operation are possible thereby. The external combustion reduces also the maintenance and the emissions in a measure not known with conventional engine technologies. The development steps are finished. The result is the world-wide first concept for the commercial, stationary application of decentralized micro-CHP on Stirling technology basis, which goes into series. (orig.) [de

  11. The 1-kW solar Stirling experiment

    Science.gov (United States)

    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.

  12. Improving Free-Piston Stirling Engine Power Density

    Science.gov (United States)

    Briggs, Maxwell H.

    2016-01-01

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

  13. Overview of NASA supported Stirling thermodynamic loss research

    International Nuclear Information System (INIS)

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

    1994-01-01

    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

  14. Large eight.cylinder Stirling engine for biofuels

    DEFF Research Database (Denmark)

    Carlsen, Henrik; Biedermann, F.; Bovin, Jonas Kabell

    2003-01-01

    A large Stirling engine with an electric power output of 70 kW has been developed for small-scale CHP using wood chips and other sorts of biomass as fuel. The development of the engine is based on the results from the development of a four-cylinder Stirling engine with a power output of 35 k...... in the hot end connecting the expansion space with the hot end of the regenerator through the heater panel. However, this has resulted in comparably large dead volumes and flow losses in the connections between the heater and the regenerator/expansion volume. For the new eight-cylinder engine the design...... of the connections between the heater and the regenerator/expansion volume have been improved considerably, reducing the flow losses and internal dead volume. Results from simulations indicate an improvement of power output and efficiency of about 10%. A four cylinder double acting Stirling engine is basically...

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

    Science.gov (United States)

    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.

  16. Splitting Ward identity

    Energy Technology Data Exchange (ETDEWEB)

    Safari, Mahmoud [Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2016-04-15

    Within the background-field framework we present a path integral derivation of the splitting Ward identity for the one-particle irreducible effective action in the presence of an infrared regulator, and make connection with earlier works on the subject. The approach is general in the sense that it does not rely on how the splitting is performed. This identity is then used to address the problem of background dependence of the effective action at an arbitrary energy scale. We next introduce the modified master equation and emphasize its role in constraining the effective action. Finally, application to general gauge theories within the geometric approach is discussed. (orig.)

  17. Splitting Ward identity

    International Nuclear Information System (INIS)

    Safari, Mahmoud

    2016-01-01

    Within the background-field framework we present a path integral derivation of the splitting Ward identity for the one-particle irreducible effective action in the presence of an infrared regulator, and make connection with earlier works on the subject. The approach is general in the sense that it does not rely on how the splitting is performed. This identity is then used to address the problem of background dependence of the effective action at an arbitrary energy scale. We next introduce the modified master equation and emphasize its role in constraining the effective action. Finally, application to general gauge theories within the geometric approach is discussed. (orig.)

  18. Output characteristics of Stirling thermoacoustic engine

    International Nuclear Information System (INIS)

    Sun Daming; Qiu Limin; Wang Bo; Xiao Yong; Zhao Liang

    2008-01-01

    A thermoacoustic engine (TE), which converts thermal energy into acoustic power by the thermoacoustic effect, shows several advantages due to the absence of moving parts, such as high reliability and long lifetime associated with reduced manufacturing costs. Power output and efficiency are important criteria of the performance of a TE. In order to increase the acoustic power output and thermal efficiency of a Stirling TE, the acoustic power distribution in the engine is studied with the variable load method. It is found that the thermal efficiency is independent of the output locations along the engine under the same acoustic power output. Furthermore, when the pressure ratio is kept constant at one location along the TE, it is beneficial to increasing the thermal efficiency by exporting more acoustic power. With nitrogen of 2.5 MPa as working gas and the pressure ratio at the compliance of 1.20 in the experiments, the acoustic power is measured at the compliance and the resonator simultaneously. The maximum power output, thermal efficiency and exergy efficiency reach 390.0 W, 11.2% and 16.0%, which are increased by 51.4%, 24.4% and 19.4%, respectively, compared to those with a single R-C load with 750 ml reservoir at the compliance. This research will be instructive for increasing the efficiency and making full use of the acoustic energy of a TE

  19. Dynamics of the Ross-Stirling engine

    Energy Technology Data Exchange (ETDEWEB)

    Doige, A G; Walker, G

    1986-01-01

    A computer model has been developed for the simulation of the dynamic loading in a Stirling engine having a Ross linkage as the drive mechanism. The model is based on a complete theoretical formulation of the dynamics of the system. The masses and moments of inertia of all moving components have been included in the model. The computer program can be used for determining the effect of changes in many design parameters on the geometry, velocities, accelerations, dynamic loading and reactions at all pin connections and engine-mount locations. In this paper, emphasis is given to assessing the general characteristics of the reaction forces at the pin connections and to the reduction of overall engine shaking forces by simple balancing methods. The most heavily loaded element in the engine is the pin connecting the crank and the yoke. The force at that location is a combination of a static load produced by gas pressure in the cylinders and a combined inertia load for the whole engine which increases with the square of the rotational speed. 6 refs., 12 figs., 2 tabs.

  20. Stirling/hydraulic artificial heart power source

    International Nuclear Information System (INIS)

    Johnston, R.P.; Bennett, A.; Emigh, S.G.; Griffith, W.R.; Noble, J.E.; Perrone, R.E.; White, M.A.; Martini, W.R.; Alexander, J.E.

    1977-01-01

    The REL power source combines the high efficiency of Stirling engines with the reliability, efficiency, and flexibility of hydraulic power transfer and control to ensure long system life and physiological effectiveness. Extended life testing has been achieved with an engine (2.6 years) and hydraulic actuator/controller (1.6 years). Peak power source efficiency is 15.5 percent on 5 to 10 watts delivered to the blood pump push plate with 33 watts steady thermal input. Planned incorporation of power source output control is expected to reduce daily average thermal input to 18 watts. Animal in-vivo tests with an assist heart have consistently demonstrated required performance by biological synchronization and effective ventricle relief. Volume and weight are 0.93 liter and 2.4 kg (excluding blood pump) with an additional 0.4 liter of low temperature foam insulation required to preclude tissue thermal damage. Carefully planned development of System 7 is expected to produce major reductions in size

  1. Linear Generator for a Free Piston Stirling Engine

    Directory of Open Access Journals (Sweden)

    OROS (POP Teodora Susana

    2014-05-01

    Full Text Available In this paper we present some aspects about the design of a Stirling engine driven linear generator. There are summarised the main steps of the magnetic and electric calculations with application to a particular case of a cogeneration plant bassed on Stirling engine. The designed linear generator is of fixed coil and moving magnets type. There are presented and a finite element method (FEM simulation of magnetic field. The linear generator design starts with the characteristics of the rare earth permanent magnets existing on the market.

  2. Evaluation Of Different Power Conditioning Options For Stirling Generators

    Science.gov (United States)

    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.

  3. Four-Cylinder Stirling-Engine Computer Program

    Science.gov (United States)

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

    1986-01-01

    Computer program developed for simulating steady-state and transient performance of four-cylinder Stirling engine. In model, four cylinders interconnected by four working spaces. Each working space contains seven volumes: one for expansion space, heater, cooler, and compression space and three for regenerator. Thermal time constant for regenerator mass associated with each regenator gas volume. Former code generates results very quickly, since it has only 14 state variables with no energy equation. Current code then used to study various aspects of Stirling engine in much more detail. Program written in FORTRAN IV for use on IBM 370 computer.

  4. Traffic dispersion through a series of signals with irregular split

    Science.gov (United States)

    Nagatani, Takashi

    2016-01-01

    We study the traffic behavior of a group of vehicles moving through a sequence of signals with irregular splits on a roadway. We present the stochastic model of vehicular traffic controlled by signals. The dynamic behavior of vehicular traffic is clarified by analyzing traffic pattern and travel time numerically. The group of vehicles breaks up more and more by the irregularity of signal's split. The traffic dispersion is induced by the irregular split. We show that the traffic dispersion depends highly on the cycle time and the strength of split's irregularity. Also, we study the traffic behavior through the series of signals at the green-wave strategy. The dependence of the travel time on offset time is derived for various values of cycle time. The region map of the traffic dispersion is shown in (cycle time, offset time)-space.

  5. The Splitting Loope

    Science.gov (United States)

    Wilkins, Jesse L. M.; Norton, Anderson

    2011-01-01

    Teaching experiments have generated several hypotheses concerning the construction of fraction schemes and operations and relationships among them. In particular, researchers have hypothesized that children's construction of splitting operations is crucial to their construction of more advanced fractions concepts (Steffe, 2002). The authors…

  6. The Splitting Group

    Science.gov (United States)

    Norton, Anderson; Wilkins, Jesse L. M.

    2012-01-01

    Piagetian theory describes mathematical development as the construction and organization of mental operations within psychological structures. Research on student learning has identified the vital roles of two particular operations--splitting and units coordination--play in students' development of advanced fractions knowledge. Whereas Steffe and…

  7. Multiple Cylinder Free-Piston Stirling Machinery

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    Muratore-Ginanneschi, Paolo; Schwieger, Kay

    2015-10-01

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

  9. Comparison of ORC Turbine and Stirling Engine to Produce Electricity from Gasified Poultry Waste

    Directory of Open Access Journals (Sweden)

    Franco Cotana

    2014-08-01

    Full Text Available The Biomass Research Centre, section of CIRIAF, has recently developed a biomass boiler (300 kW thermal powered, fed by the poultry manure collected in a nearby livestock. All the thermal requirements of the livestock will be covered by the heat produced by gas combustion in the gasifier boiler. Within the activities carried out by the research project ENERPOLL (Energy Valorization of Poultry Manure in a Thermal Power Plant, funded by the Italian Ministry of Agriculture and Forestry, this paper aims at studying an upgrade version of the existing thermal plant, investigating and analyzing the possible applications for electricity production recovering the exceeding thermal energy. A comparison of Organic Rankine Cycle turbines and Stirling engines, to produce electricity from gasified poultry waste, is proposed, evaluating technical and economic parameters, considering actual incentives on renewable produced electricity.

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

    Science.gov (United States)

    Rauch, J.; Dochat, G.

    1985-01-01

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

  11. On designing low pressure loss working spaces for a planar Stirling micromachine

    Science.gov (United States)

    Hachey, M.-A.; Léveillé, É.; Fréchette, L. G.; Formosa, F.

    2015-12-01

    In this paper, research was undertaken with the objective to design low pressure loss working spaces for a Stirling cycle micro heat engine operating from low temperature waste heat. This planar free-piston heat engine is anticipated to operate at the kHz level with mm3 displacement. Given the resonant nature of the free-piston configuration, the complexity of its working gas’ flow geometry and its projected high operating frequency, flow analysis is relatively complex. Design considerations were thus based on fast prototyping and experimentation. Results show that geometrical features, such as a sharp 90° corner between the regenerator and working spaces, are strong contributors to pressure losses. This research culminated into a promising revised working space configuration for engine start-up, as it considerably reduced total pressure losses, more than 80% at Re = 700, from the original design.

  12. Development of a Dynamic, End-to-End Free Piston Stirling Convertor Model

    Science.gov (United States)

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

    2003-01-01

    A dynamic model for a free-piston Stirling convertor is being developed at the NASA Glenn Research Center. The model is an end-to-end system model that includes the cycle thermodynamics, the dynamics, and electrical aspects of the system. The subsystems of interest are the heat source, the springs, the moving masses, the linear alternator, the controller and the end-user load. The envisioned use of the model will be in evaluating how changes in a subsystem could affect the operation of the convertor. The model under development will speed the evaluation of improvements to a subsystem and aid in determining areas in which most significant improvements may be found. One of the first uses of the end-to-end model will be in the development of controller architectures. Another related area is in evaluating changes to details in the linear alternator.

  13. Superfluid stirling refrigerator: A new method for cooling below 1 Kelvin

    International Nuclear Information System (INIS)

    Kotsubo, V.; Swift, G.W.

    1990-01-01

    We have invented and built a new type of cryocooler, which we call the superfluid Stirling refrigerator (SSR). The first prototype reached 0.6 K from a starting temperature of 1.2 K. The working fluid of the SSR is the 3 He solute in a superfluid 3 He-- 4 He solution. At low temperatures, the superfluid 4 He is in its quantum ground state, and therefore is thermodynamically inert, while the 3 He solute has the thermodynamic properties of a dense ideal gas. Thus, in principle, any refrigeration cycle that can use an ideal gas can also use the 3 He solute as working fluid. In our SSR prototype, bellows-sealed superleak pistons driven by a room-temperature camshaft work on the 3 He solute. Ultimately, we anticipate elimination of moving parts by analogy with pulse-tube refrigeration. 15 refs., 6 figs

  14. Investigation of the vibration and EMC characteristics of miniature Stirling electric coolers for space applications

    Science.gov (United States)

    Kondratjev, V.; Gostilo, V.; Owens, anb A.

    2017-08-01

    We present the results of an investigation into the detrimental effects that electromechanical coolers can have on the spectral performance of compact, large volume HPGe spectrometers for space applications. Both mechanical vibration and electromagnetic pickup effects were considered, as well as a comparative assessment between three miniature Stirling cycle coolers—two Ricor model K508 coolers and one Thales model RM3 cooler. In spite of the limited number of coolers tested, the following conclusions can be made. There are significant differences in the vibration characteristics not only between the various types of cooler but also between coolers of the same type. It was also found that compared to the noise induced by mechanical vibrations, electromagnetic interference emanating from the embedded controllers does not significantly impact the energy resolution of detectors.

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

    Science.gov (United States)

    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.

  16. How to Overcome Numerical Challenges to Modeling Stirling Engines

    Science.gov (United States)

    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. Experimental and theoretical investigation of Stirling engine heater: Parametrical optimization

    International Nuclear Information System (INIS)

    Gheith, R.; Hachem, H.; Aloui, F.; Ben Nasrallah, S.

    2015-01-01

    Highlights: • A Stirling engine was investigated to optimize its operation and its performance. • The porous medium present the highest amount of heat exchanged in a Stirling engine. • The heater characteristics are determinant points to enhance the thermal exchange in Stirling engine. • All operation parameters influence the heater performances. • Thermal and exergy heater efficiencies are sensible to temperature and pressure. - Abstract: The aim of this work is to optimize γ Stirling engine performances with a special care given to the heater. This latter consists of 20 tubes in order to increase the exchange area between the working gas and the hot source. Different parameters were chosen to evaluate numerically and experimentally the heater. The selected four independent parameters are: heating temperature (300–500 °C), initial filling pressure (3–8 bar), cooling water flow rate (0.2–3 l/min) and frequency (2–7 Hz). The amount of energy exchanged in the heater is significantly influenced by the frequency and heating temperature but it is slightly enhanced with the increase in the cooling water flow rate. The thermal and the exergy efficiencies of the heater are very sensible to the temperature and pressure variations.

  18. Structural Benchmark Testing for Stirling Convertor Heater Heads

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2016-01-01

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

  20. Advanced Controller for the Free-Piston Stirling Convertor

    Science.gov (United States)

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

    2004-01-01

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

  1. New 5 Kilowatt Free-Piston Stirling Space Converter Developments

    Science.gov (United States)

    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 converter 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 converter 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 converter assembly (SCA) which will serve as a prototype of one or more SCAs that will make up the final 30 kW Stirling Converter Power System. Assumed requirements for this new converter 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.

  2. Advanced Controller Developed for the Free-Piston Stirling Convertor

    Science.gov (United States)

    Gerber, Scott S.

    2005-01-01

    A free-piston Stirling power convertor is being considered as an advanced power-conversion technology for future NASA deep-space missions requiring long-life radioisotope power systems. The NASA Glenn Research Center has identified key areas where advanced technologies can enhance the capability of Stirling energy-conversion systems. One of these is power electronic controls. Current power-conversion technology for Glenn-tested Stirling systems consists of an engine-driven linear alternator generating an alternating-current voltage controlled by a tuning-capacitor-based alternating-current peak voltage load controller. The tuning capacitor keeps the internal alternator electromotive force (EMF) in phase with its respective current (i.e., passive power factor correction). The alternator EMF is related to the piston velocity, which must be kept in phase with the alternator current in order to achieve stable operation. This tuning capacitor, which adds volume and mass to the overall Stirling convertor, can be eliminated if the controller can actively drive the magnitude and phase of the alternator current.

  3. Radioisotope power system based on derivative of existing Stirling engine

    International Nuclear Information System (INIS)

    Schock, A.; Or, C.T.; Kumar, V.

    1995-01-01

    In a recent paper, the authors presented the results of a system design study of a 75-watt(c) RSG (Radioisotope Stirling Generator) for possible application to the Pluto Fast Flyby mission. That study was based on a Stirling engine design generated by MTI (Mechanical Technology, Inc.). The MTI design was a derivative of a much larger (13 kwe) engine that they had developed and tested for NASA's LERC. Clearly, such a derivative would be a major extrapolation (downsizing) from what has actually been built and tested. To avoid that, the present paper describes a design for a 75-watt RSG system based on derivatives of a small (11-watt) engine and linear alternator system that has been under development by STC (Stirling Technology Company) for over three years and that has operated successfully for over 15,000 hours as of March 1995. Thus, the STC engines would require much less extrapolation from proven designs. The design employs a heat source consisting of two standard General Purpose Heat Source (GPHS) modules, coupled to four Stirling engines with linear alternators, any three of which could deliver the desired 75-watt(e) output if the fourth should fail. The four engines are coupled to four common radiators with redundant heatpipes for rejecting the engines' waste heat to space. The above engine and radiator redundancies promote system reliability. The paper describes detailed analyses to determine the effect of radiator geometry on system mass and performance, before and after an engine or heatpipe failure

  4. Technology development for a Stirling radioisotope power system

    International Nuclear Information System (INIS)

    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

  5. Degenerate r-Stirling Numbers and r-Bell Polynomials

    Science.gov (United States)

    Kim, T.; Yao, Y.; Kim, D. S.; Jang, G.-W.

    2018-01-01

    The purpose of this paper is to exploit umbral calculus in order to derive some properties, recurrence relations, and identities related to the degenerate r-Stirling numbers of the second kind and the degenerate r-Bell polynomials. Especially, we will express the degenerate r-Bell polynomials as linear combinations of many well-known families of special polynomials.

  6. Advanced Stirling Radioisotope Generator EU2 Anomaly Investigation

    Science.gov (United States)

    Lewandowski, Edward J.; Dobbs, Michael W.; Oriti, Salvatore M.

    2016-01-01

    The Advanced Stirling Radioisotope Generator (ASRG) Engineering Unit 2 (EU2) is the highest fidelity electrically-heated Stirling radioisotope generator built to date. NASA Glenn Research Center (GRC) completed the assembly of the ASRG EU2 in September, 2014 using hardware from the now cancelled ASRG flight development project. The ASRG EU2 integrated the first pair of Sunpower's ASC-E3 Stirling convertors (ASC-E3 #1 and #2) in an aluminum generator housing with Lockheed Martin's Engineering Development Unit (EDU) 4 controller. After just 179 hours of EU2 generator operation, the first power fluctuation occurred on ASC-E3 #1. The first power fluctuation occurred 175 hours later on ASC-E3 #2. Over time, the power fluctuations became more frequent on both convertors and larger in magnitude. Eventually the EU2 was shut down in January, 2015. An anomaly investigation was chartered to determine root cause of the power fluctuations and other anomalous observations. A team with members from GRC, Sunpower, and Lockheed Martin conducted a thorough investigation of the EU2 anomalies. Findings from the EU2 disassembly identified proximate causes of the anomalous observations. Discussion of the team's assessment of the primary possible failure theories, root cause, and conclusions is provided. Recommendations are made for future Stirling generator development to address the findings from the anomaly investigation. Additional findings from the investigation are also discussed.

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

    Science.gov (United States)

    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.

  8. The κ-Generalizations of Stirling Approximation and Multinominal Coefficients

    Directory of Open Access Journals (Sweden)

    Tatsuaki Wada

    2013-11-01

    Full Text Available Stirling approximation of the factorials and multinominal coefficients are generalized based on the κ-generalized functions introduced by Kaniadakis. We have related the κ-generalized multinominal coefficients to the κ-entropy by introducing a new κ-product operation, which exists only when κ ≠ 0.

  9. Tsallis p, q-deformed Touchard polynomials and Stirling numbers

    Science.gov (United States)

    Herscovici, O.; Mansour, T.

    2017-01-01

    In this paper, we develop and investigate a new two-parametrized deformation of the Touchard polynomials, based on the definition of the NEXT q-exponential function of Tsallis. We obtain new generalizations of the Stirling numbers of the second kind and of the binomial coefficients and represent two new statistics for the set partitions.

  10. Advanced Stirling Radioisotope Generator Engineering Unit 2 Anomaly Investigation

    Science.gov (United States)

    Lewandowski, Edward J.; Dobbs, Michael W.; Oriti, Salvatore M.

    2018-01-01

    The Advanced Stirling Radioisotope Generator (ASRG) Engineering Unit 2 (EU2) is the highest fidelity electrically heated Stirling radioisotope generator built to date. NASA Glenn Research Center completed the assembly of the ASRG EU2 in September 2014 using hardware from the now cancelled ASRG flight development project. The ASRG EU2 integrated the first pair of Sunpower's Advanced Stirling Convertors (ASC-E3 #1 and #2) in an aluminum generator housing with Lockheed Martin's (LM's) Engineering Development Unit (EDU) 4 controller. After just 179 hr of EU2 generator operation, the first power fluctuation occurred on ASC-E3 #1. The first power fluctuation occurred 175 hr later on ASC-E3 #2. Over time, the power fluctuations became more frequent on both convertors and larger in magnitude. Eventually the EU2 was shut down in January 2015. An anomaly investigation was chartered to determine root cause of the power fluctuations and other anomalous observations. A team with members from Glenn, Sunpower, and LM conducted a thorough investigation of the EU2 anomalies. Findings from the EU2 disassembly identified proximate causes of the anomalous observations. Discussion of the team's assessment of the primary possible failure theories, root cause, and conclusions is provided. Recommendations are made for future Stirling generator development to address the findings from the anomaly investigation. Additional findings from the investigation are also discussed.

  11. Split warhead simultaneous impact

    Directory of Open Access Journals (Sweden)

    Rahul Singh Dhari

    2017-12-01

    Full Text Available A projectile system is proposed to improve efficiency and effectiveness of damage done by anti-tank weapon system on its target by designing a ballistic projectile that can split into multiple warheads and engage a target at the same time. This idea has been developed in interest of saving time consumed from the process of reloading and additional number of rounds wasted on target during an attack. The proposed system is achieved in three steps: Firstly, a mathematical model is prepared using the basic equations of motion. Second, An Ejection Mechanism of proposed warhead is explained with the help of schematics. Third, a part of numerical simulation which is done using the MATLAB software. The final result shows various ranges and times when split can be effectively achieved. With the new system, impact points are increased and hence it has a better probability of hitting a target.

  12. Isospin splittings of baryons

    International Nuclear Information System (INIS)

    Varga, Kalman; Genovese, Marco; Richard, Jean-Marc; Silvestre-Brac, Bernard

    1998-01-01

    We discuss the isospin-breaking mass differences among baryons, with particular attention in the charm sector to the Σ c + -Σ c 0 , Σ c ++ -Σ c 0 , and Ξ c + -Ξ c 0 splittings. Simple potential models cannot accommodate the trend of the available data on charm baryons. More precise measurements would offer the possibility of testing how well potential models describe the non-perturbative limit of QCD

  13. Superfluid thermodynamic cycle refrigerator

    Science.gov (United States)

    Swift, Gregory W.; Kotsubo, Vincent Y.

    1992-01-01

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of .sup.3 He in a single phase .sup.3 He-.sup.4 He solution. The .sup.3 He in superfluid .sup.4 He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A single phase solution of liquid .sup.3 He at an initial concentration in superfluid .sup.4 He is contained in a first variable volume connected to a second variable volume through a superleak device that enables free passage of .sup.4 He while restricting passage of .sup.3 He. The .sup.3 He is compressed (concentrated) and expanded (diluted) in a phased manner to carry out the selected thermal cycle to remove heat from the heat load for cooling below 1 K.

  14. (O)Mega split

    Energy Technology Data Exchange (ETDEWEB)

    Benakli, Karim; Darmé, Luc; Goodsell, Mark D. [Sorbonne Universités, UPMC Univ Paris 06, UMR 7589,LPTHE, F-75005, Paris (France); CNRS, UMR 7589,LPTHE, F-75005, Paris (France)

    2015-11-16

    We study two realisations of the Fake Split Supersymmetry Model (FSSM), the simplest model that can easily reproduce the experimental value of the Higgs mass for an arbitrarily high supersymmetry scale M{sub S}, as a consequence of swapping higgsinos for equivalent states, fake higgsinos, with suppressed Yukawa couplings. If the LSP is identified as the main Dark matter component, then a standard thermal history of the Universe implies upper bounds on M{sub S}, which we derive. On the other hand, we show that renormalisation group running of soft masses aboveM{sub S} barely constrains the model — in stark contrast to Split Supersymmetry — and hence we can have a “Mega Split” spectrum even with all of these assumptions and constraints, which include the requirements of a correct relic abundance, a gluino life-time compatible with Big Bang Nucleosynthesis and absence of signals in present direct detection experiments of inelastic dark matter. In an appendix we describe a related scenario, Fake Split Extended Supersymmetry, which enjoys similar properties.

  15. Study of temperature distribution in a Stirling engine regenerator

    International Nuclear Information System (INIS)

    Gheith, R.; Aloui, F.; Ben Nasrallah, S.

    2014-01-01

    Highlights: • A Gamma-Stirling engine is experimented to determine the optimal operation parameters. • A set of experiment reveals a difference of temperature between regenerator sides. • A phenomenon which consumes a part of the produced energy by the engine is highlighted. • A multi-objectif study based on experimental design methodology is developed. • The optimal set of operation parameters maximizing the engine power is proposed. - Abstract: A gamma Stirling engine is studied in this paper. A special care was accorded to the instrumentation of this engine and especially the instrumentation of the regenerator. A preliminarily set of experimental measurement reveals a difference of temperature between both regenerator sides. A second set of experiments was proposed to detect the influence of this phenomenon on Stirling engine performances. The asymmetry of heat transfer inside the Stirling engine regenerator’s is one of the important phenomenons which consume a part of the produced energy. Two experiments are made to find out the causes of this asymmetry. In order to know the influence of the different operation parameters on this new phenomenon the experimental design method is adopted. The experimental design is an alternative to identify the parameters sets allowing optimal Stirling engine performances. A central composite rotatable design was adopted for minimizing the asymmetry of temperature between both regenerator sides and maximizes the engine brake power. The selected four independent parameters are: heating temperature (300 °C–500 °C), initial filling pressure (3 bar–8 bar), cooling water flow rate (0.2 l/m–3 l/min) and operation time (4–20 min after study regime). The four adopted factors are experimentally varied. The results show that the heating temperature is the most significant factor for the studied phenomenon. The major damages caused by this phenomenon will be presented too

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

    International Nuclear Information System (INIS)

    Bents, D.J.

    1992-08-01

    The design of a multihundred-watt Dynamic Isotope Power System (DIPS), based on the US 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

  17. Stirling Convertor Performance Mapping Test Results for Future Radioisotope Power Systems

    Science.gov (United States)

    Qiu, Songgang; Peterson, Allen A.; Faultersack, Franklyn D.; Redinger, Darin L.; Augenblick, John E.

    2004-02-01

    Long-life radioisotope-fueled generators based on free-piston Stirling convertors 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 performance-testing its Stirling generators to provide data for potential system integration contractors. This paper describes the most recent test results from the STC RemoteGen™ 55 W-class Stirling generators (RG-55). Comparisons are made between the new data and previous Stirling thermodynamic simulation models. Performance-mapping tests are presented including variations in: internal charge pressure, cold end temperature, hot end temperature, alternator temperature, input power, and variation of control voltage.

  18. Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine

    OpenAIRE

    Aladayleh, Wail; Alahmer, Ali

    2015-01-01

    This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively....

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

    Science.gov (United States)

    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.

  20. Technoeconomy of different solid oxide fuel cell based hybrid cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    Gas turbine, steam turbine and heat engine (Stirling engine) is used as bottoming cycle for a solid oxide fuel cell plant to compare different plants efficiencies, CO2 emissionsand plants cost in terms of $/kW. Each plant is then integrated with biomass gasification and finally six plants...

  1. Thermodynamic analysis and experimental investigation of a Solo V161 Stirling cogeneration unit

    International Nuclear Information System (INIS)

    Rogdakis, E.D.; Antonakos, G.D.; Koronaki, I.P.

    2012-01-01

    In order to investigate the Stirling engine implementation technology, a Solo Stirling Engine V161 cogeneration module has been installed at the Laboratory of Applied Thermodynamics of National Technical University of Athens. A special thermodynamic analysis of the engine's performance has been conducted introducing and utilizing specially designed computing codes along with the thermal balance study of the unit. Measurements were conducted under different operational conditions concerning various heat load stages of the engine, working pressure, as well as electric power production. Analysis of the experimental results has shown that the overall performance of the Stirling unit proved very promising and quite adequate for various areal applications, equally competing with other CHP systems. The performance of the unit experienced significant stability all over the operating range. The power stand ratio 0.35 differentiates Stirling cogeneration units from others that use diverging technologies significantly. The energy savings using a Stirling CHP unit, in respect to the concurrent use of a thermal and an electrical system at the same equivalent power has revealed 36.8%. -- Highlights: ► Thermodynamic analysis of an a-type Stirling engine. ► Development of generated electrical and thermal power of the m-CHP Solo Stirling Unit to engine's load comparison. ► Stirling m-CHP until heat balance analysis. ► Evaluation of the Solo Stirling V161 unit efficiency.

  2. Performance Analysis and Optimization of a Solar Powered Stirling Engine with Heat Transfer Considerations

    Directory of Open Access Journals (Sweden)

    Chia-En Ho

    2012-09-01

    Full Text Available This paper investigates the optimization of the performance of a solar powered Stirling engine based on finite-time thermodynamics. Heat transference in the heat exchangers between a concentrating solar collector and the Stirling engine is studied. The irreversibility of a Stirling engine is considered with the heat transfer following Newton's law. The power generated by a Stirling engine is used as an objective function for maximum power output design with the concentrating solar collector temperature and the engine thermal efficiency as the optimization parameters. The maximum output power of engine and its corresponding system parameters are determined using a genetic algorithm.

  3. Innovative Stirling Convertor for Distributed Electric Power from Thermal Energy Recovery, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — SCCAQ Energy, LLC (SCCAQ) in collaboration with Temple University and Infinia Technology Corporation (ITC) proposes to develop a Reliable Stirling Convertor (RSC)...

  4. To capabilities of heat engines with gas working medium in closed cycle

    International Nuclear Information System (INIS)

    Kotov, V.M.; Tikhomirov, L.N.; Rajkhanov, N.A.; Kotov, S.V.

    2003-01-01

    The effort gives analysis of performance of engines and heat pumps with closed cycles based on use of well practiced adiabatic and isobaric processes. Advantages of theses cycles are demonstrated as compared to Stirling engines, and capabilities of their application in piston machines. (author)

  5. RE-1000 free-piston Stirling engine update

    Science.gov (United States)

    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.

  6. Thermal energy storage for the Stirling engine powered automobile

    Science.gov (United States)

    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.

  7. Mechanically-cooled germanium detector using two stirling refrigerators

    International Nuclear Information System (INIS)

    Katagiri, Masaki; Kobayashi, Yoshii; Takahashi, Koji

    1996-01-01

    In this paper, we present a developed mechanically-cooled germanium gamma-ray detector using Stirling refrigerators. Two Stirling refrigerators having cooling faculty of 1.5W at 80K were used to cool down a germanium detector element to 77K instead of a dewar containing liquid nitrogen. An 145cm 3 (56.0mmf x 59.1 mml) closed-end Ge(I) detector having relative detection efficiency of 29.4% was attached at the refrigerators. The size of the detector was 60cml x 15cmh x 15cmw. The lowest cooling temperature, 70K was obtained after 8 hours operation. The energy resolutions for 1.33MeV gamma-rays and for pulser signals were 2.43keV and 1.84keV at an amplifier shaping time of 2μsec, respectively

  8. The 4 K Stirling cryocooler demonstration. Final report No. 8, 1 May 1990-30 April 1992

    International Nuclear Information System (INIS)

    Stacy, W.D.

    1992-09-01

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  11. Geometrical splitting in Monte Carlo

    International Nuclear Information System (INIS)

    Dubi, A.; Elperin, T.; Dudziak, D.J.

    1982-01-01

    A statistical model is presented by which a direct statistical approach yielded an analytic expression for the second moment, the variance ratio, and the benefit function in a model of an n surface-splitting Monte Carlo game. In addition to the insight into the dependence of the second moment on the splitting parameters the main importance of the expressions developed lies in their potential to become a basis for in-code optimization of splitting through a general algorithm. Refs

  12. Ecological optimization and performance study of irreversible Stirling and Ericsson heat engines

    International Nuclear Information System (INIS)

    Tyagi, S K; Kaushik, S C; Salhotra, R

    2002-01-01

    The concept of finite time thermodynamics is used to determine the ecological function of irreversible Stirling and Ericsson heat engine cycles. The ecological function is defined as the power output minus power loss (irreversibility), which is the ambient temperature times, the entropy generation rate. The ecological function is maximized with respect to cycle temperature ratio and the expressions for the corresponding power output and thermal efficiency are derived at the optimal operating conditions. The effect of different operating parameters, the effectiveness on the hot, cold and the regenerative side heat exchangers, the cycle temperature ratio, heat capacitance ratio and the internal irreversibility parameter on the maximum ecological function are studied. It is found that the effect of regenerator effectiveness is more than the hot and cold side heat exchangers and the effect of the effectiveness on cold side heat exchanger is more than the effectiveness on the hot side heat exchanger on the maximum ecological function. It is also found that the effect of internal irreversibility parameter is more than the other parameters not only on the maximum ecological function but also on the corresponding power output and the thermal efficiency

  13. Ecological optimization and performance study of irreversible Stirling and Ericsson heat engines

    Science.gov (United States)

    Tyagi, S. K.; Kaushik, S. C.; Salhotra, R.

    2002-10-01

    The concept of finite time thermodynamics is used to determine the ecological function of irreversible Stirling and Ericsson heat engine cycles. The ecological function is defined as the power output minus power loss (irreversibility), which is the ambient temperature times, the entropy generation rate. The ecological function is maximized with respect to cycle temperature ratio and the expressions for the corresponding power output and thermal efficiency are derived at the optimal operating conditions. The effect of different operating parameters, the effectiveness on the hot, cold and the regenerative side heat exchangers, the cycle temperature ratio, heat capacitance ratio and the internal irreversibility parameter on the maximum ecological function are studied. It is found that the effect of regenerator effectiveness is more than the hot and cold side heat exchangers and the effect of the effectiveness on cold side heat exchanger is more than the effectiveness on the hot side heat exchanger on the maximum ecological function. It is also found that the effect of internal irreversibility parameter is more than the other parameters not only on the maximum ecological function but also on the corresponding power output and the thermal efficiency.

  14. The study, design and simulation of a free piston Stirling engine linear alternatorThe study, design and simulation of a free piston Stirling engine linear alternator

    Directory of Open Access Journals (Sweden)

    Teodora Susana Oros

    2014-12-01

    Full Text Available This paper presents a study, design and simulation of a Free Piston Stirling Engine Linear Alternator. There are presented the main steps of the magnetic and electric calculations for a permanent magnet linear alternator of fixed coil and moving magnets type. Finally, a detailed thermal, mechanical and electrical model for a Stirling engine linear alternator have been made in SIMULINK simulation program. The linear alternator simulation model uses a controllable DC voltage which simulates the linear alternator combined with a rectifier, a variable load and a DC-DC converter, which compensates for the variable nature of Stirling engine operation, and ensures a constant voltage output regardless of the load.

  15. Hybrid heat recovery - flat plate Stirling engine system

    International Nuclear Information System (INIS)

    Bogdanizh, A.M.; Budin, R.; Sutlovizh, I.

    2000-01-01

    In this paper, the possibility of process condensate heat recovery for boiler water preheating as well as for combined heat and power production for chosen process in textile industry has been investigated. The garment industry requires low pressure process steam or hot water for which production expensive fossil fuel should be used. Fuel usage can be reduced by various energy conservation methods. During the process a great quantity of hot condensate or waste hot water is rejected in the sewage system. To reduce heat wastes and improve technological process this condensate could be returned to the boiler for feed water preheating. When 60% condensate is returned to the steam generator about 8 % natural gas is saved. The rest of the condensate should be used for driving low temperature flat plate Stirling motor the advantage of the flat plate Stirling engine is ability to work at low temperatures. This engine produces electrical energy which can put in motion an electrogenerator in the same plant. While Stirling engine can be used electrical power and economical effect could be much greater using such a hybrid system the process waste heat is not only converted into useful work but at the same time thermal pollution is greatly diminished. (Author)

  16. Characterization of the Advanced Stirling Radioisotope Generator EU2

    Science.gov (United States)

    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.

  17. A free-piston Stirling cryocooler using metal diaphragms

    Science.gov (United States)

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

    2016-12-01

    A novel concept for a free-piston Stirling cryocooler has been proposed. The concept uses a pair of metal diaphragms to seal and suspend the displacer of a free-piston Stirling cryocooler. The diaphragms allow the displacer to move without rubbing or moving seals, potentially resulting in a long-life mechanism. When coupled to a metal diaphragm pressure wave generator, the system produces a complete Stirling cryocooler with no rubbing parts in the working gas space. Initial modelling of this concept using the Sage modelling tool indicates the potential for a useful cryocooler. A proof-of-concept prototype was constructed and achieved cryogenic temperatures. A second prototype was designed and constructed using the experience gained from the first. The prototype produced 29 W of cooling at 77 K and reached a no-load temperature of 56 K. Sage predicted the macroscopic behaviour of the prototype well but did not provide sufficient insights to improve performance significantly. This paper presents details of the development, modelling and testing of the proof-of-concept prototype and a second, improved prototype.

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

    International Nuclear Information System (INIS)

    Dudenhoefer, J.E.; Winter, J.M.

    1994-01-01

    An overview is presented of the NASA Lewis Research Center Free-Piston Stirling Space Power Converter Technology Program. This work is being conducted under NASA's Civil Space Technology Initiative. The goal of the CSTI High Capacity Power Element 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. This paper will discuss Stirling experience in 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. This paper provides an update of progress in some of these technologies leading off with a discussion of free-piston Stirling experience in space

  19. Parametric study on beta-type Stirling engine

    International Nuclear Information System (INIS)

    Abuelyamen, A.; Ben-Mansour, R.; Abualhamayel, H.; Mokheimer, Esmail M.A.

    2017-01-01

    Highlights: • A parametric study of laminar flow for a β-type Stirling engine was performed. • The optimum charge pressure varies from gas to another. • Stirling engine runs better below the optimum charge pressure for H 2 and He. • Power output increases with temperature while thermal efficiency decreases. • For air and He, output power increases with temperature differences (T H − T C ). - Abstract: In this work, a parametric study on a β-type Stirling engine with no regenerator was conducted numerically using ANSYS fluent 14.5 software. The three parameters that were studied are; initial charge pressure, thermal boundary condition; and three different types of working fluids (Air, He and H 2 ). Variable thermal properties of these gases were adopted to get more realistic results. The results include a comparison of the amount of heat transfer, power output, and thermal efficiency. It was found that the best engine performance is achieved when H 2 gas is used as working fluid. Moreover, results revealed that each of the power output and the efficiency has different optimum charge pressure. Additionally, it was found that there is a small variation in the pressure across the engine chambers, which results in miss matching between the net heat transfer rates and power output calculated from PV-diagram. This error is higher when the air is used as working fluid, especially at high charge pressure.

  20. Structural Dynamics Testing of Advanced Stirling Convertor Components

    Science.gov (United States)

    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.

  1. Feasibility study of dish/stirling power systems in Turkey

    Science.gov (United States)

    Zilanlı, Gülin Acarol; Eray, Aynur

    2017-06-01

    In this study, two different commercial dish/stirling systems, SES (Stirling Energy Systems) and WGA-ADDS (WGAssociates - Advanced Dish Development System), are modeled using the "System Advisor Model" (SAM) modeling software in designated settlement areas. Both systems are modeled for the US state of Albuquerque, where they were designed, and Turkish provinces of Ankara, Van, Muğla, Mersin, Urfa and Konya. At first, the dish/stirling system is optimized according to the power output values and the system loss parameters. Then, the layout of the solar field is designed with an installed capacity of 600kW both of SES and WGA-ADDS systems, Upon securing the most suitable layout, the system is modeled for the aforementioned settlements using the optimum output values gathered from the parametric analysis. As a result of the simulation studies, the applicability of this model is discussed according to the power output and the efficiency. Although Turkey is located in an area called "the sun belt" where solar energy technologies can be used, there is no advanced application of these systems. This study aims to discuss the application of these systems in detail and to pave the way for future studies in this field.

  2. A conceptual study of the potential for automotive-derived and free-piston Stirling engines in 30- to 400-kilowatt stationary power applications

    Science.gov (United States)

    Vatsky, A.; Chen, H. S.; Dineen, J.

    1982-01-01

    The technical feasibility of applying automotive-derived kinematic and free-piston Stirling engine concepts for stationary applications was explored. Automotive-derived engines offer cost advantages by providing a mature and developd engine technology base with downrating and parts commonality options for specific applications. Two engine sizes (30 and 400 kW), two Stirling engine configurations (kinematic and free-piston), and two output systems (crankshaft and hydraulic pump) were studied. The study includes the influences of using either hydrogen or helium as the working gas. The first kinematic configuration selects an existing Stirling engine design from an automotive application and adapts it to stationary requirements. A 50,000-hour life requirement was established by downrating the engine to 40 kW and reducing auxiliary loads. Efficiency improvements were gained by selective material and geometric variations and peak brake efficiency of 36.8 percent using helium gas was achieved. The second design was a four-cylinder, 400 kW engine, utilizing a new output drive system known as the z-crank, which provides lower friction losses and variable stroke power control. Three different material and working gas combinations were considered. Brake efficiency levels varied from 40.5 percent to 45.6 percent. A 37.5 kW single-cycle, free-piston hydraulic output design was generated by scaling one cylinder of the original automotive engine and mating it to a counterbalanced reciprocal hydraulic pump. Metallic diaphragms were utilized to transmit power.

  3. A conceptual study of the potential for automotive-derived and free-piston Stirling engines in 30- to 400-kilowatt stationary power applications

    Science.gov (United States)

    Vatsky, A.; Chen, H. S.; Dineen, J.

    1982-05-01

    The technical feasibility of applying automotive-derived kinematic and free-piston Stirling engine concepts for stationary applications was explored. Automotive-derived engines offer cost advantages by providing a mature and developd engine technology base with downrating and parts commonality options for specific applications. Two engine sizes (30 and 400 kW), two Stirling engine configurations (kinematic and free-piston), and two output systems (crankshaft and hydraulic pump) were studied. The study includes the influences of using either hydrogen or helium as the working gas. The first kinematic configuration selects an existing Stirling engine design from an automotive application and adapts it to stationary requirements. A 50,000-hour life requirement was established by downrating the engine to 40 kW and reducing auxiliary loads. Efficiency improvements were gained by selective material and geometric variations and peak brake efficiency of 36.8 percent using helium gas was achieved. The second design was a four-cylinder, 400 kW engine, utilizing a new output drive system known as the z-crank, which provides lower friction losses and variable stroke power control. Three different material and working gas combinations were considered. Brake efficiency levels varied from 40.5 percent to 45.6 percent. A 37.5 kW single-cycle, free-piston hydraulic output design was generated by scaling one cylinder of the original automotive engine and mating it to a counterbalanced reciprocal hydraulic pump. Metallic diaphragms were utilized to transmit power.

  4. Effects of Novel Fin Shape of High Temperature Heat Exchanger on 1 kW Class Stirling Engine

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Joon; Kim, Seok Yeon [Kookmin Univ., Seoul (Korea, Republic of)

    2017-08-15

    In this research, numerical analysis was carried out on novel and existing fins, adjusted in terms of factors such as length, spacing, and angle, of a high-temperature heat exchanger for a 1 kW class Stirling engine, designed as a prime mover for a domestic cogeneration system. The performance improvement as a result of shape optimization was confirmed with numerical analysis by including the air preheater, which was not considered during optimization. However, a negative heat flux was observed in the cylinder head portion. This phenomenon was clarified by analyzing the exhaust gas and wall surface temperature of the combustion chamber. Furthermore, assuming an ideal cycle, the effects of heat transfer enhancement on the thermodynamic cycle and system performance were predicted.

  5. Preliminary Results from Simulations of Temperature Oscillations in Stirling Engine Regenerator Matrices

    DEFF Research Database (Denmark)

    Andersen, Stig Kildegård; Carlsen, Henrik; Thomsen, Per Grove

    2006-01-01

    The objective of this study has been to create a Stirling engine model for studying the effects of regenerator matrix temperature oscillations on Stirling engine performance. A one-dimensional model with axial discretisation of engine components has been formulated using the control volume method...

  6. Simulation, design and thermal analysis of a solar Stirling engine using MATLAB

    International Nuclear Information System (INIS)

    Shazly, J.H.; Hafez, A.Z.; El Shenawy, E.T.; Eteiba, M.B.

    2014-01-01

    Highlights: • Modeling and simulation for a prototype of the solar-powered Stirling engine. • The solar-powered Stirling engine working at the low temperature range. • Estimating output power from the solar Stirling engine using Matlab program. • Solar radiation simulation program presents a solar radiation data using MATLAB. - Abstract: This paper presents the modeling and simulation for a prototype of the solar-powered Stirling engine working at the low temperature range. A mathematical model for the thermal analysis of the solar-powered low temperature Stirling engine with heat transfer is developed using Matlab program. The model takes into consideration the effect of the absorber temperature on the thermal analysis like as radiation and convection heat transfer between the absorber and the working fluid as well as radiation and convection heat transfer between the lower temperature plate and the working fluid. Hence, the present analysis provides a theoretical guidance for designing and operating of the solar-powered low temperature Stirling engine system, as well as estimating output power from the solar Stirling engine using Matlab program. This study attempts to demonstrate the potential of the low temperature Stirling engine as an option for the prime movers for Photovoltaic tracking systems. The heat source temperature is 40–60 °C as the temperature available from the sun directly

  7. Modeling for control of a kinematic wobble-yoke Stirling engine

    NARCIS (Netherlands)

    Garcia-Canseco, Eloisa; Alvarez-Aguirre, Alejandro; Scherpen, Jacquelien M. A.

    In this paper we derive the dynamical model of a four-cylinder double-acting wobble-yoke Stirling engine. In addition to the classical thermodynamics methods that dominate the literature of Stirling mechanisms, we present a control systems viewpoint to analyze the dynamic properties of the engine.

  8. One-dimensional numerical simulation of the Stirling-type pulse-tube refrigerator

    NARCIS (Netherlands)

    Etaati, M.; Mattheij, R.M.M.; Tijsseling, A.S.; Waele, de A.T.A.M.

    2007-01-01

    Change of title: One-dimensional numerical simulation of the Stirling-type pulse-tube cooler. Pulse-tube refrigeration (PTR) is a new technology for cooling down to extremely low temperatures. In this paper a particular type, the so-called Stirling single-stage refrigerator, is considered. A

  9. Hot air engines: Study of a Stirling engine and of an Ericsson engine; Moteurs thermiques a apport de chaleur externe: etude d'un moteur stirling et d'un moteur ericsson

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet, S.

    2005-11-15

    In the current energy context, we attend the development of technologies of production of 'clean' energy. Thus, news prospects like thermodynamic solar energy conversion or waste energy conversion are offered to research on 'renewable energies'. Within this framework, we are interested in hot air engines: Stirling and Ericsson engines. First of all, this thesis concerns the study of a small Stirling engine on which we measured the fluid instantaneous temperature and pressure in various points. The original results obtained are compared to results from two different analyses. We conclude that these models are not suitable to explain the experimental results. Then, we study a micro-cogeneration system based on an Ericsson engine coupled with a system of natural gas combustion. An Ericsson engine is a reciprocating engine working on a JOULE cycle. The objective of this plant is to produce 11 kW of electric output as well as useful heat. In order to design this system, we carried out energetic, exergetic and exergo-economic studies. (author)

  10. The 23rd Stirling Physics Meeting

    Science.gov (United States)

    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

  11. Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine

    Directory of Open Access Journals (Sweden)

    Wail Aladayleh

    2015-01-01

    Full Text Available This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively. The indication work, real shaft power and specific fuel consumption for Stirling engine, and the exhaust power losses for IC engine are calculated. The study shows the availability and possibility of recovery of the waste heat from internal combustion engine using Stirling engine.

  12. Results from tests of a Stirling engine and wood chips gasifier plant

    DEFF Research Database (Denmark)

    Carlsen, Henrik; Bovin, Jonas Kabell; Werling, J.

    2002-01-01

    The combination of thermal gasification and a Stirling engine is an interesting concept for use in small Combined Heat and Power (CHP) plants based on biomass, because the need for gas cleaning is eliminated and problems with fouling of the Stirling engine heater are considerably reduced....... Furthermore, the overall electric efficiency of the system can be improved. At the Technical University of Denmark a small CHP plant based on a Stirling engine and an updraft gasifier has been developed and tested successfully. The advantages of updraft gasifiers are the simplicity and that the amount...... of the Stirling engine reduces the problems with tar to a minor problem in the design of the burner. The Stirling engine, which has an electric power output of 35 kW, is specifically designed for utilisation of fuels with a content of particles. The gas burner for the engine is designed for low specific energy...

  13. Performance analysis on free-piston Stirling cryocooler based on an idealized mathematical model

    Science.gov (United States)

    Guo, Y. X.; Chao, Y. J.; Gan, Z. H.; Li, S. Z.; Wang, B.

    2017-12-01

    Free-piston Stirling cryocoolers have extensive applications for its simplicity in structure and decrease in mass. However, the elimination of the motor and the crankshaft has made its thermodynamic characteristic different from that of Stirling cryocoolers with displacer driving mechanism. Therefore, an idealized mathematical model has been established, and with this model, an attempt has been made to analyse the thermodynamic characteristic and the performance of free-piston Stirling cryocooler. To certify this mathematical model, a comparison has been made between the model and a numerical model. This study reveals that due to the displacer damping force necessary for the production of cooling capacity, the free-piston Stirling cryocooler is inherently less efficient than Stirling cryocooler with displacer driving mechanism. Viscous flow resistance and incomplete heat transfer in the regenerator are the two major causes of the discrepancy between the results of the idealized mathematical model and the numerical model.

  14. A comparison of radioisotope Brayton and Stirling system for lunar surface mobile power

    International Nuclear Information System (INIS)

    Harty, R.B.

    1991-01-01

    A study was performed by the Rocketdyne Division of Rockwell 2.5-kWe modular dynamic isotope power system (DIPS) using a Stirling power conversion system. The results of this study were compared with similar results performed under the DIPS program using a Brayton power conversion system. The study indicated that the Stirling power module has 20% lower mass and 40% lower radiator area than the Brayton module. However, the study also revealed that because the Stirling power module requires a complex heat pipe arrangment to transport heat from the isotope to the Stirling heater head and a pumped NaK heat rejection loop, the Stirling module is much more difficult to integrate with the isotope heat source and heat rejection system

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

    International Nuclear Information System (INIS)

    Schreiber, Jeffrey G.

    2001-01-01

    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

  16. Numerical investigation of a dual-loop EGR split strategy using a split index and multi-objective Pareto optimization

    International Nuclear Information System (INIS)

    Park, Jungsoo; Song, Soonho; Lee, Kyo Seung

    2015-01-01

    Highlights: • Model-based control of dual-loop EGR system is performed. • EGR split index is developed to provide non-dimensional index for optimization. • EGR rates are calibrated using EGR split index at specific operating conditions. • Multi-objective Pareto optimization is performed to minimize NO X and BSFC. • Optimum split strategies are suggested with LP-rich dual-loop EGR at high load. - Abstract: A proposed dual-loop exhaust-gas recirculation (EGR) system that combines the features of high-pressure (HP) and low-pressure (LP) systems is considered a key technology for improving the combustion behavior of diesel engines. The fraction of HP and LP flows, known as the EGR split, for a given dual-loop EGR rate play an important role in determining the engine performance and emission characteristics. Therefore, identifying the proper EGR split is important for the engine optimization and calibration processes, which affect the EGR response and deNO X efficiencies. The objective of this research was to develop a dual-loop EGR split strategy using numerical analysis and one-dimensional (1D) cycle simulation. A control system was modeled by coupling the 1D cycle simulation and the control logic. An EGR split index was developed to investigate the HP/LP split effects on the engine performance and emissions. Using the model-based control system, a multi-objective Pareto (MOP) analysis was used to minimize the NO X formation and fuel consumption through optimized engine operating parameters. The MOP analysis was performed using a response surface model extracted from Latin hypercube sampling as a fractional factorial design of experiment. By using an LP rich dual-loop EGR, a high EGR rate was attained at low, medium, and high engine speeds, increasing the applicable load ranges compared to base conditions

  17. Development and validation of a thermodynamic model for the performance analysis of a gamma Stirling engine prototype

    International Nuclear Information System (INIS)

    Araoz, Joseph A.; Cardozo, Evelyn; Salomon, Marianne; Alejo, Lucio; Fransson, Torsten H.

    2015-01-01

    This work presents the development and validation of a numerical model that represents the performance of a gamma Stirling engine prototype. The model follows a modular approach considering ideal adiabatic working spaces; limited internal and external heat transfer through the heat exchangers; and mechanical and thermal losses during the cycle. In addition, it includes the calculation of the mechanical efficiency taking into account the crank mechanism effectiveness and the forced work during the cycle. Consequently, the model aims to predict the work that can be effectively taken from the shaft. The model was compared with experimental data obtained in an experimental rig built for the engine prototype. The results showed an acceptable degree of accuracy when comparing with the experimental data, with errors ranging from ±1% to ±8% for the temperature in the heater side, less than ±1% error for the cooler temperatures, and ±1 to ±8% for the brake power calculations. Therefore, the model was probed adequate for study of the prototype performance. In addition, the results of the simulation reflected the limited performance obtained during the prototype experiments, and a first analysis of the results attributed this to the forced work during the cycle. The implemented model is the basis for a subsequent parametric analysis that will complement the results presented. - Highlights: • A numerical model for a Stirling engine was developed. • A mechanical efficiency analysis was included in the model. • The model was validated with experimental data of a novel prototype. • The model results permit a deeper insight into the engine operation

  18. Split-illumination electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Inada, Yoshikatsu [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Matsuda, Tsuyoshi [Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Taniyama, Akira [Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd., Amagasaki, Hyogo 660-0891 (Japan); Shindo, Daisuke [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Tonomura, Akira [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Okinawa Institute of Science and Technology, Graduate University, Onna-son, Okinawa 904-0495 (Japan); Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395 (Japan)

    2012-07-23

    We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

  19. Split-illumination electron holography

    International Nuclear Information System (INIS)

    Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon; Inada, Yoshikatsu; Matsuda, Tsuyoshi; Taniyama, Akira; Shindo, Daisuke; Tonomura, Akira

    2012-01-01

    We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

  20. Two-Loop Splitting Amplitudes

    International Nuclear Information System (INIS)

    Bern, Z.

    2004-01-01

    Splitting amplitudes govern the behavior of scattering amplitudes at the momenta of external legs become collinear. In this talk we outline the calculation of two-loop splitting amplitudes via the unitarity sewing method. This method retains the simple factorization properties of light-cone gauge, but avoids the need for prescriptions such as the principal value or Mandelstam-Leibbrandt ones. The encountered loop momentum integrals are then evaluated using integration-by-parts and Lorentz invariance identities. We outline a variety of applications for these splitting amplitudes

  1. Two-loop splitting amplitudes

    International Nuclear Information System (INIS)

    Bern, Z.; Dixon, L.J.; Kosower, D.A.

    2004-01-01

    Splitting amplitudes govern the behavior of scattering amplitudes at the momenta of external legs become collinear. In this talk we outline the calculation of two-loop splitting amplitudes via the unitarity sewing method. This method retains the simple factorization properties of light-cone gauge, but avoids the need for prescriptions such as the principal value or Mandelstam-Leibbrandt ones. The encountered loop momentum integrals are then evaluated using integration-by-parts and Lorentz invariance identities. We outline a variety of applications for these splitting amplitudes

  2. Design of stirling engine operating at low temperature difference

    Directory of Open Access Journals (Sweden)

    Sedlák Josef

    2018-01-01

    Full Text Available There are many sources of free energy available in the form of heat that is often simply wasted. The aim of this paper is to design and build a low temperature differential Stirling engine that would be powered exclusively from heat sources such as waste hot water or focused solar rays. A prototype is limited to a low temperature differential modification because of a choice of ABSplus plastic as a construction material for its key parts. The paper is divided into two parts. The first part covers a brief history of Stirling engine and its applications nowadays. Moreover, it describes basic principles of its operation that are supplemented by thermodynamic relations. Furthermore, an analysis of applied Fused Deposition Modelling has been done since the parts with more complex geometry had been manufactured using this additive technology. The second (experimental part covers 4 essential steps of a rapid prototyping method - Computer Aided Design of the 3D model of Stirling engine using parametric modeller Autodesk Inventor, production of its components using 3D printer uPrint, assembly and final testing. Special attention was devoted to last two steps of the process since the surfaces of the printed parts were sandpapered and sprayed. Parts, where an ABS plus plastic would have impeded the correct function, had been manufactured from aluminium and brass by cutting operations. Remaining parts had been bought in a hardware store as it would be uneconomical and unreasonable to manufacture them. Last two chapters of the paper describe final testing, mention the problems that appeared during its production and propose new approaches that could be used in the future to improve the project.

  3. Test results and commercialization plans for long life Stirling generators

    International Nuclear Information System (INIS)

    Erbeznik, R.M.; White, M.A.

    1996-01-01

    Many optimistic predictions regarding commercialization of Stirling engines have been announced over the years, but to date no real successes have emerged. STC is excited to announce the availability of beta prototypes for its RemoteGen trademark family of free-piston Stirling generators. STC is working with suppliers, manufacturers, and beta customers to commercialize the RemoteGen family of generators. STC is proving that these machines overcome previously inhibiting barriers by providing long life, high reliability, cost effective mass production, and market relevance. Stirling power generators are generally acknowledged to offer much higher conversion efficiencies than direct energy conversion systems. Life and reliability, on the other hand, are generally considered superior for direct conversion systems, as established by the exceptional endurance records (though with degradation) for thermoelectric (TE) and photovoltaic (PV) systems. STC's unique approaches combine dynamic system efficiency with static system reliability. The RemoteGen family presently includes a 10-watt RG-10, a 350-watt RG-350, and with 1-kW and 3-kW sizes planned for the future. They all use the same basic configuration with flexure bearings, clearance seals, and moving iron linear alternators. The third generation RG-10 has entered limited production with a radioisotope-fueled version, and a niche market for a propane-fueled version has been identified. Market analysis has led STC to focus on early commercial production of the RG-350. The linear alternator power module portion of the RG-350 is also used in its sister BeCool trademark family of coolers as the linear motor. By using a common power module, both programs will benefit by each other's commercialization efforts. The technology behind the RemoteGen generators, test results, and plans for commercialization are described in this paper

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

    International Nuclear Information System (INIS)

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

    1996-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  6. Advanced Stirling Convertor Development for NASA Radioisotope Power Systems

    Science.gov (United States)

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

    2015-01-01

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

  7. Stirling converters for space dynamic power concepts with 2 to 130 We output

    International Nuclear Information System (INIS)

    Ross, B.A.

    1995-01-01

    Three innovative Stirling converter concepts are described. Two concepts are based on Pluto Fast Flyby (PFF) mission requirements, where two General Purpose Heat Source (GPHS) modules provide the thermal input. The first concept (PFF2) considers a power system with two opposed Stirling converters; the second concept (PFF4) considers four opposed Stirling converters. For both concepts the Stirling converters are designed to vary their power production capability to compensate for the failure of one Stirling converter. While the net thermal efficiency of PFF4 is a few percentage points lower than PFF2, the total Stirling converter mass of PFF4 is half that for PFF2. The third concept (ITTI) is designed to supply 2 watts of power for weather stations on the Martian surface. The predicted thermal performance of the ITTI is low compared to PFF2 and PFF4, yet the ITTI concept offers significant advantages compared to currently available power systems at the 2-watt power level. All three concepts are based on long-life technology demonstrated by an 11-watt output Stirling generator that as of March 1995 has accumulated over 15,000 operating hours without maintenance

  8. Overview of Multi-Kilowatt Free-Piston Stirling Power Conversion Research at Glenn Research Center

    Science.gov (United States)

    Geng, Steven M.; Mason, Lee S.; Dyson, Rodger W.; Penswick, L. Barry

    2008-01-01

    As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors and a pair of commercially available pressure wave generators (which will be plumbed together to create a high power Stirling linear alternator test rig) have been procured for in-house testing at Glenn Research Center (GRC). Delivery of both the Stirling convertors and the linear alternator test rig is expected by October 2007. The 1 kW class free-piston Stirling convertors will be tested at GRC to map and verify performance. The convertors will later be modified to operate with a NaK liquid metal pumped loop for thermal energy input. The high power linear alternator test rig will be used to map and verify high power Stirling linear alternator performance and to develop power management and distribution (PMAD) methods and techniques. This paper provides an overview of the multi-kilowatt free-piston Stirling power conversion work being performed at GRC.

  9. Overview of Multi-kilowatt Free-Piston Stirling Power Conversion Research at GRC

    Science.gov (United States)

    Geng, Steven M.; Mason, Lee S.; Dyson, Rodger W.; Penswick, L. Barry

    2008-01-01

    As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors and a pair of commercially available pressure wave generators (which will be plumbed together to create a high power Stirling linear alternator test rig) have been procured for in-house testing at Glenn Research Center. Delivery of both the Stirling convertors and the linear alternator test rig is expected by October, 2007. The 1 kW class free-piston Stirling convertors will be tested at GRC to map and verify performance. The convertors will later be modified to operate with a NaK liquid metal pumped loop for thermal energy input. The high power linear alternator test rig will be used to map and verify high power Stirling linear alternator performance and to develop power management and distribution (PMAD) methods and techniques. This paper provides an overview of the multi-kilowatt free-piston Stirling power conversion work being performed at GRC.

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

    Science.gov (United States)

    Schreiber, Jeffrey G.

    2007-01-01

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

  11. Overview of Multi-Kilowatt Free-Piston Stirling Power Conversion Research at GRC

    Science.gov (United States)

    Geng, Steven M.; Mason, Lee S.; Dyson, Rodger W.; Penswick, L. Barry

    2008-01-01

    As a step towards development of Stirling power conversion for potential use in Fission Surface Power (FSP) systems, a pair of commercially available 1 kW class free-piston Stirling convertors and a pair of commercially available pressure wave generators (which will be plumbed together to create a high power Stirling linear alternator test rig) have been procured for in-house testing at Glenn Research Center. Delivery of both the Stirling convertors and the linear alternator test rig is expected by October, 2007. The 1 kW class free-piston Stirling convertors will be tested at GRC to map and verify performance. The convertors will later be modified to operate with a NaK liquid metal pumped loop for thermal energy input. The high power linear alternator test rig will be used to map and verify high power Stirling linear alternator performance and to develop power management and distribution (PMAD) methods and techniques. This paper provides an overview of the multi-kilowatt free-piston Stirling power conversion work being performed at GRC.

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

    Science.gov (United States)

    Schreiber, Jeffrey G.

    2001-01-01

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

  13. β Style Free-Piston Stirling Engine Control System Research

    Directory of Open Access Journals (Sweden)

    Xu Jian

    2016-01-01

    Full Text Available For the Free-Piston Stirling Engines (FPSE control system, a three -phase bridge circuit is reused as the system output about rectifier and start inverter. When FPSE system is in the power stage, the double closed loop control strategy and optimization algorithm of PI control parameters is adopted to ensure the highest system transmission efficiency under the requirements of the system output power and guarantee the stability of the running system. The simulation results prove the effectiveness of the above research content.

  14. Stochastic Stirling Engine Operating in Contact with Active Baths

    Directory of Open Access Journals (Sweden)

    Ruben Zakine

    2017-04-01

    Full Text Available A Stirling engine made of a colloidal particle in contact with a nonequilibrium bath is considered and analyzed with the tools of stochastic energetics. We model the bath by non Gaussian persistent noise acting on the colloidal particle. Depending on the chosen definition of an isothermal transformation in this nonequilibrium setting, we find that either the energetics of the engine parallels that of its equilibrium counterpart or, in the simplest case, that it ends up being less efficient. Persistence, more than non-Gaussian effects, are responsible for this result.

  15. Stochastic Stirling Engine Operating in Contact with Active Baths

    Science.gov (United States)

    Zakine, Ruben; Solon, Alexandre; Gingrich, Todd; van Wijland, Frédéric

    2017-04-01

    A Stirling engine made of a colloidal particle in contact with a nonequilibrium bath is considered and analyzed with the tools of stochastic energetics. We model the bath by non Gaussian persistent noise acting on the colloidal particle. Depending on the chosen definition of an isothermal transformation in this nonequilibrium setting, we find that either the energetics of the engine parallels that of its equilibrium counterpart or, in the simplest case, that it ends up being less efficient. Persistence, more than non Gaussian effects, are responsible for this result.

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

    Science.gov (United States)

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

    1986-01-01

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

  17. EXPERIMENTAL INVESTIGATION OF AN AIR CHARGED LOW POWERED STIRLING ENGINE

    Directory of Open Access Journals (Sweden)

    Can ÇINAR

    2004-01-01

    Full Text Available In this study, an air charged, low powered manufactured ? type Stirling engine was investigated experimentally. Tests were conducted at 800, 900 and 1000 °C hot source temperatures, 1, 1.5, 2, 2.5, 3, 3.5 bars air charge pressure. The variation of engine power depending on the charge pressure and hot source temperature for two different heat transfer area was investigated experimentally. Maximum output power was obtained at 1000 °C and 3 bars charge pressure as 58 W at 441 rpm. Engine speed was reached at 846 rpm without load.

  18. Development of a Thermoacoustic Stirling Engine Technology Demonstrator

    Science.gov (United States)

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

    2014-08-01

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

  19. Integral finned heater and cooler for stirling engines

    Science.gov (United States)

    Corey, John A.

    1984-01-01

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

  20. Benchmark Tests for Stirling Convertor Heater Head Life Assessment Conducted

    Science.gov (United States)

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

    2004-01-01

    A new in-house test capability has been developed at the NASA Glenn Research Center, where a critical component of the Stirling Radioisotope Generator (SRG) is undergoing extensive testing to aid the development of analytical life prediction methodology and to experimentally aid in verification of the flight-design component's life. The new facility includes two test rigs that are performing creep testing of the SRG heater head pressure vessel test articles at design temperature and with wall stresses ranging from operating level to seven times that (see the following photograph).

  1. Development and validation of the Stirling Eating Disorder Scales.

    Science.gov (United States)

    Williams, G J; Power, K G; Miller, H R; Freeman, C P; Yellowlees, A; Dowds, T; Walker, M; Parry-Jones, W L

    1994-07-01

    The development and reliability/validity check of an 80-item, 8-scale measure for use with eating disorder patients is presented. The Stirling Eating Disorder Scales (SEDS) assess anorexic dietary behavior, anorexic dietary cognitions, bulimic dietary behavior, bulimic dietary cognitions, high perceived external control, low assertiveness, low self-esteem, and self-directed hostility. The SEDS were administered to 82 eating disorder patients and 85 controls. Results indicate that the SEDS are acceptable in terms of internal consistency, reliability, group validity, and concurrent validity.

  2. Parametric System Model for a Stirling Radioisotope Generator

    Science.gov (United States)

    Schmitz, Paul C.

    2015-01-01

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

  3. Free-Piston Stirling Machine for Extreme Temperatures

    Science.gov (United States)

    Wood, James Gary (Inventor)

    2013-01-01

    A free piston Stirling machine including a thermal buffer tube extending from the machine's expansion space and surrounded by its heat rejector and its regenerator, a displacer cylinder extending from the thermal buffer tube to the compression space and surrounded by the heat rejecting heat exchanger, and a displacer that reciprocates within an excursion limit that extends into the regenerator by no more than 20% of the length of the regenerator during normal operation and preferably within excursion limits that are substantially the length of the heat rejector.

  4. Inhibition delay increases neural network capacity through Stirling transform

    Science.gov (United States)

    Nogaret, Alain; King, Alastair

    2018-03-01

    Inhibitory neural networks are found to encode high volumes of information through delayed inhibition. We show that inhibition delay increases storage capacity through a Stirling transform of the minimum capacity which stabilizes locally coherent oscillations. We obtain both the exact and asymptotic formulas for the total number of dynamic attractors. Our results predict a (ln2) -N-fold increase in capacity for an N -neuron network and demonstrate high-density associative memories which host a maximum number of oscillations in analog neural devices.

  5. The toughness of split graphs

    NARCIS (Netherlands)

    Woeginger, G.J.

    1998-01-01

    In this short note we argue that the toughness of split graphs can be computed in polynomial time. This solves an open problem from a recent paper by Kratsch et al. (Discrete Math. 150 (1996) 231–245).

  6. ISR split-field magnet

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    The experimental apparatus used at intersection 4 around the Split-Field Magnet by the CERN-Bologna Collaboration (experiment R406). The plastic scintillator telescopes are used for precise pulse-height and time-of-flight measurements.

  7. Triadic split-merge sampler

    Science.gov (United States)

    van Rossum, Anne C.; Lin, Hai Xiang; Dubbeldam, Johan; van der Herik, H. Jaap

    2018-04-01

    In machine vision typical heuristic methods to extract parameterized objects out of raw data points are the Hough transform and RANSAC. Bayesian models carry the promise to optimally extract such parameterized objects given a correct definition of the model and the type of noise at hand. A category of solvers for Bayesian models are Markov chain Monte Carlo methods. Naive implementations of MCMC methods suffer from slow convergence in machine vision due to the complexity of the parameter space. Towards this blocked Gibbs and split-merge samplers have been developed that assign multiple data points to clusters at once. In this paper we introduce a new split-merge sampler, the triadic split-merge sampler, that perform steps between two and three randomly chosen clusters. This has two advantages. First, it reduces the asymmetry between the split and merge steps. Second, it is able to propose a new cluster that is composed out of data points from two different clusters. Both advantages speed up convergence which we demonstrate on a line extraction problem. We show that the triadic split-merge sampler outperforms the conventional split-merge sampler. Although this new MCMC sampler is demonstrated in this machine vision context, its application extend to the very general domain of statistical inference.

  8. Biomass gasification integrated with a solid oxide fuel cell and Stirling engine

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    An integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power application is analyzed. The target for electricity production is 120 kW. Woodchips are used as gasification feedstock to produce syngas, which is then used to feed the SOFC stacks...... for electricity production. Unreacted hydrocarbons remaining after the SOFC are burned in a catalytic burner, and the hot off-gases from the burner are recovered in a Stirling engine for electricity and heat production. Domestic hot water is used as a heat sink for the Stirling engine. A complete balance...

  9. Study of Stirling Engine Efficiency Coefficient under Conditions Being Close to Real Ones

    Directory of Open Access Journals (Sweden)

    R. M. Abramian

    2013-01-01

    Full Text Available An absolute internal efficiency coefficient of the Stirling engine has been obtained without regenerator and with regenerator under conditions when van der Waals gas serves as a working medium. The paper reveals that while taking into account own volume of molecules thermal efficiency coefficient of the Stirling engine depends on mole number of the working medium  and it is slightly increasing  in comparison with the case of an ideal gas. The paper gives consideration to heat losses while the Stirling machine operates with heat regeneration. Dependence of regeneration rate on time of heat transfer has been obtained in the paper. 

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

    Science.gov (United States)

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

    1992-01-01

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

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

    Science.gov (United States)

    Martini, W. R.

    1978-01-01

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

  12. Many-objective thermodynamic optimization of Stirling heat engine

    International Nuclear Information System (INIS)

    Patel, Vivek; Savsani, Vimal; Mudgal, Anurag

    2017-01-01

    This paper presents a rigorous investigation of many-objective (four-objective) thermodynamic optimization of a Stirling heat engine. Many-objective optimization problem is formed by considering maximization of thermal efficiency, power output, ecological function and exergy efficiency. Multi-objective heat transfer search (MOHTS) algorithm is proposed and applied to obtain a set of Pareto-optimal points. Many objective optimization results form a solution in a four dimensional hyper objective space and for visualization it is represented on a two dimension objective space. Thus, results of four-objective optimization are represented by six Pareto fronts in two dimension objective space. These six Pareto fronts are compared with their corresponding two-objective Pareto fronts. Quantitative assessment of the obtained Pareto solutions is reported in terms of spread and the spacing measures. Different decision making approaches such as LINMAP, TOPSIS and fuzzy are used to select a final optimal solution from Pareto optimal set of many-objective optimization. Finally, to reveal the level of conflict between these objectives, distribution of each decision variable in their allowable range is also shown in two dimensional objective spaces. - Highlights: • Many-objective (i.e. four objective) optimization of Stirling engine is investigated. • MOHTS algorithm is introduced and applied to obtain a set of Pareto points. • Comparative results of many-objective and multi-objectives are presented. • Relationship of design variables in many-objective optimization are obtained. • Optimum solution is selected by using decision making approaches.

  13. Progress in High Power Free-Piston Stirling Convertor Development

    Science.gov (United States)

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

    2008-09-01

    The U.S. Space Exploration Policy has established a vision for human exploration of the moon and Mars. One option for power for future outposts on the lunar and Martian surfaces is a nuclear reactor coupled with a free-piston Stirling convertor at a power level of 30-40 kWe. A 25 kW convertor was developed in the 1990s under the SP-100 program. This system consisted of two 12.5 kWe engines connected at their hot ends and mounted in tandem to cancel vibration. Recently, NASA began a new project with Auburn University to develop a 5 kWe, single convertor for use in such a possible lunar power system. Goals of this development program include a specific power in excess of 140 We/kg at the convertor level, lifetime in excess of five years and a control system that will safely manage the convertors in case of an emergency. Foster-Miller, Inc. is developing the 5 kWe Stirling Convertor Assembly. The characteristics of the design along with progress in developing the system will be described.

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

    Science.gov (United States)

    Wang, Xiao-Yen, J.

    2012-01-01

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

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

    Science.gov (United States)

    Wong, Wayne A.; Cornell, Peggy A.

    2012-01-01

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

  16. A Microfabricated Involute-Foil Regenerator for Stirling Engines

    Science.gov (United States)

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

    2007-01-01

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

  17. Design, construction and experimental investigation of a Stirling refrigerator for freezing in supermarkets. Final report; Auslegung, Bau und experimentelle Untersuchung einer Stirling-Kaeltemaschine fuer die Tiefkuehlung in Supermaerkten. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Steimle, F.; Schikora, H.; Mai, M.; Siegel, A.

    2000-10-01

    Several theoretical investigations have shown that Stirling refrigerators could be a promising alternative for refrigeration at 'near-ambient' temperatures (above -40 C). These theoretical statements shall be validated in an actual research project by measurements taken from a Stirling refrigerator that is optimised for this range of temperature. In this paper first measurement results of this new developed Solo 161 Stirling refrigerator will be presented. Problems are investigated by detailed measurements. Possible improvements are described. (orig.) [German] Verschiedene theoretische Untersuchungen haben gezeigt, dass Stirling-Kaeltemaschinen eine interessante Alternative fuer die Kaelteerzeugung im sog. 'umgebungsnahen' Temperaturbereich (oberhalb von -40 C) darstellen koennten. In einem derzeit laufenden Forschungsvorhaben sollen diese theoretischen Untersuchungen durch Messungen an einer fuer diesen Temperaturbereich optimierten Stirling-Kaeltemaschine ueberprueft werden. In diesem Aufsatz werden erste Messergebnisse dieser neu entwickelten Solo 161 Stirling-Kaeltemaschine praesentiert. Anhand detaillierter Messergebnisse werden Schwachstellen lokalisiert und moegliche Verbesserungsmassnahmen beschrieben. (orig.)

  18. Conceptual design of free-piston Stirling conversion system for solar power units

    Science.gov (United States)

    Loktionov, Iu. V.

    A conversion system has been conceptually designed for solar power units of the dish-Stirling type. The main design objectives were to demonstrate the possibility of attaining such performance characteristics as low manufacturing and life cycle costs, high reliability, long life, high efficiency, power output stability, self-balance, automatic (or self-) start-up, and easy maintenance. The system design includes a heat transfer and utilization subsystem with a solar receiver, a free-piston engine, an electric power generation subsystem, and a control subsystem. The working fluid is helium. The structural material is stainless steel for hot elements, aluminum alloys and plastics for others. The electric generation subunit can be fabricated in three options: with an induction linear alternator, with a permanent magnet linear alternator, and with a serial rotated induction generator and a hydraulic drive subsystem. The heat transfer system is based on heat pipes or the reflux boiler principle. Several models of heat transfer units using a liquid metal (Na or Na-K) have been created and demonstrated.

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

    Science.gov (United States)

    Martini, William R.

    1989-01-01

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

  20. Reversible and irreversible heat engine and refrigerator cycles

    Science.gov (United States)

    Leff, Harvey S.

    2018-05-01

    Although no reversible thermodynamic cycles exist in nature, nearly all cycles covered in textbooks are reversible. This is a review, clarification, and extension of results and concepts for quasistatic, reversible and irreversible processes and cycles, intended primarily for teachers and students. Distinctions between the latter process types are explained, with emphasis on clockwise (CW) and counterclockwise (CCW) cycles. Specific examples of each are examined, including Carnot, Kelvin and Stirling cycles. For the Stirling cycle, potentially useful task-specific efficiency measures are proposed and illustrated. Whether a cycle behaves as a traditional refrigerator or heat engine can depend on whether it is reversible or irreversible. Reversible and irreversible-quasistatic CW cycles both satisfy Carnot's inequality for thermal efficiency, η ≤ η C a r n o t . Irreversible CCW cycles with two reservoirs satisfy the coefficient of performance inequality K ≤ K C a r n o t . However, an arbitrary reversible cycle satisfies K ≥ K C a r n o t when compared with a reversible Carnot cycle operating between its maximum and minimum temperatures, a potentially counterintuitive result.

  1. Splitting: The Development of a Measure.

    Science.gov (United States)

    Gerson, Mary-Joan

    1984-01-01

    Described the development of a scale that measures splitting as a psychological structure. The construct validity of the splitting scale is suggested by the positive relationship between splitting scores and a diagnostic measure of the narcissistic personality disorder, as well as a negative relationship between splitting scores and levels of…

  2. Application Model for a Stirling Engine Micro-Generation System in Caravans in Different European Locations

    Directory of Open Access Journals (Sweden)

    Carlos Ulloa

    2013-02-01

    Full Text Available This article describes a simple model obtained from a commercial Stirling engine and used for heating a caravan. The Stirling engine has been tested in the lab under different electrical load conditions, and the operating points obtained are presented. As an application of the model, a series of transient simulations was performed using TRNSYS. During these simulations, the caravan is traveling throughout the day and is stationary at night. Therefore, during the night-time hours, the heating system is turned on by means of the Stirling engine. The study was performed for each month of the year in different European cities. The different heating demand profiles for different cities induce variation in the electricity production, as it has been assumed that electricity is only generated when the thermal demand requires the operation of the Stirling system. As a result, a comparison of the expected power generation in different European cities is presented.

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

    Science.gov (United States)

    Riecke, George T.; Stotts, Robert E.

    1992-01-01

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

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

    Science.gov (United States)

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

    2004-01-01

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

  5. Developing a Free-Piston Stirling Convertor for advanced radioisotope space power systems

    Science.gov (United States)

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

    2002-01-01

    The Department of Energy (DOE) has selected Free-Piston Stirling Convertors as a technology for future advanced radioisotope space power systems. In August 2000, DOE awarded competitive Phase I, Stirling Radioisotope Generator (SRG) power system integration contracts to three major aerospace contractors, resulting in SRG conceptual designs in February 2001. All three contractors based their designs on the Technology Demonstration Convertor (TDC) developed by Stirling Technology Company (STC) for DOE. The contract award to a single system integration contractor for Phases II and III of the SRG program is anticipated in late 2001. The first potential SRG mission is targeted for a Mars rover. This paper provides a description of the Flight Prototype (FP) Stirling convertor design as compared to the previous TDC design. The initial flight prototype units are already undergoing performance tuning at STC. The new design will be hermetically scaled and will provide a weight reduction from approximately 4.8 kg to approximately 3.9 kg. .

  6. Experimental study on the Stirling refrigerator for cooling of infrared detector

    Energy Technology Data Exchange (ETDEWEB)

    Park, S. J.; Hong, Y. J.; Kim, H. B.; Koh, D. Y. [Korea Institute of Machinery and Materials, Taejon (Korea, Republic of); Kim, J. H.; Yu, B. K. [Wooyoung, Seoul (Korea, Republic of)

    2001-07-01

    A Stirling cryocooler is relatively compact, reliable, commercially available, and uses helium as a working fluid. The FPFD Stirling cryocooler consists of two compressor pistons driven by linear motors which makes pressure waves and a pneumatically driven displacer piston with regenerator. A Free Piston and Free Displacer (FPFD) Stirling cryocooler for cooling infrared and cryo-sensors is currently under development at KIMM(Korea Institute of Machinery and Materials). In order to evaluate the feasibility of using a linear motor driving cryocooler, prototype Stirling cryocooler with a nominal cooling capacity of 0.5W at 80K was designed, fabricated and tested. The prototype has achieved no load temperature of 51K and cooling power of 0.33W.

  7. Experimental study on the Stirling refrigerator for cooling of infrared detector

    International Nuclear Information System (INIS)

    Park, S. J.; Hong, Y. J.; Kim, H. B.; Koh, D. Y.; Kim, J. H.; Yu, B. K.

    2001-01-01

    A Stirling cryocooler is relatively compact, reliable, commercially available, and uses helium as a working fluid. The FPFD Stirling cryocooler consists of two compressor pistons driven by linear motors which makes pressure waves and a pneumatically driven displacer piston with regenerator. A Free Piston and Free Displacer (FPFD) Stirling cryocooler for cooling infrared and cryo-sensors is currently under development at KIMM(Korea Institute of Machinery and Materials). In order to evaluate the feasibility of using a linear motor driving cryocooler, prototype Stirling cryocooler with a nominal cooling capacity of 0.5W at 80K was designed, fabricated and tested. The prototype has achieved no load temperature of 51K and cooling power of 0.33W

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

    Science.gov (United States)

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

    1980-01-01

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

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

    Science.gov (United States)

    Metscher, Jonathan F.; Lewandowski, Edward J.

    2015-01-01

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

  10. Novel Ring-Configuration Double-Acting Free-Piston Stirling Convertor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA SBIR-2015 Topic S3.01 seeks to evaluate and advance Stirling convertors as a potentially more efficient alternative to the radioisotope-heated thermoelectric...

  11. Performance analysis of dish solar stirling power system; Stirling engine wo mochiita taiyonetsu hatsuden system no seino yosoku

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, K; Yamaguchi, I [Meiji University, Tokyo (Japan); Naito, Y; Momose, Y [Aisin Seiki Co. Ltd., Aichi (Japan)

    1996-10-27

    In order to estimate the performance of the dish solar Stirling power system, matching and control of each component system were studied, and the performance of the 25kWe class power system was estimated on the basis of direct solar radiation measured in Miyako island, Okinawa. Application of a Stirling engine to solar heat power generation is highly effective in spite of its small scale. The total system is composed of a converging system, heat receiver, engine/generator system and control system. As the simulation result, the generator output is nearly proportional to direct solar radiation, and the system efficiency approaches to a certain constant value with an increase in direct solar radiation. As accumulated solar radiation is large, the influence of slope error of the converging mirror is comparatively small. The optimum aperture opening ratio of the heat receiver determined on the basis of mean direct solar radiation (accumulated solar radiation/{Delta}t (simulated operation time of the system)), corresponds to the primary approximation of the opening ratio for a maximum total generated output under variable direct solar radiation. 6 refs., 6 figs., 1 tab.

  12. Design and development of Stirling Engines for stationary power generation applications in the 500 to 3000 hp range. Subtask 1A report: state-of-the-art conceptual design

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-03-01

    The first portion of the Conceptual Design Study 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 is summarized. 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 sysems and to establish a pragmatic and conservative base design for a first generation hardware. Starting with an extensive screening effort, 4 engine types, i.e., V-type crank engine, radial engine, swashplate engine, and rhombic drive engine, and 3 heat transport systems, i.e., heat pipe, pressurized gas heat transport loop, and direct gas fired system, were selected. After a preliminary layout cycle, the rhombic drive engine was eliminated due to intolerable maintenance difficulties on the push rod seals. V, radial and swashplate engines were taken through a detailed design/layout cycle, to establish all important design features and reliable engine weights. After comparing engine layouts and analyzing qualitative and quantitative evaluation criteria, the V-crank engine was chosen as the candidate for a 1985 hardware demonstration.

  13. Commercialization possibilities of Stirling engine technology for microscale power generation in Sweden

    OpenAIRE

    Backman, Peter

    2012-01-01

    The presented master’s thesis has evaluated the possibility of commercializing a research project at the Royal Institute of Technologys (KTH) Department of Energy Technology (EGI) in Stockholm, Sweden, where a Stirling engine is used for renewable microscale power generation.  The purpose of the thesis has been to evaluate the current market situation and future prospects by composing a business plan under the working name MicroStirling. In the business plan a potential target group consistin...

  14. The Stirling engine. Simply explained, easily constructed. 9. rev. and enl. ed.; Der Stirlingmotor. Einfach erklaert und leicht gebaut

    Energy Technology Data Exchange (ETDEWEB)

    Viebach, Dieter

    2010-07-01

    Subsequently to a easily comprehensively description of the function and characteristics of Stirling engines, the author of the book under consideration describes the construction of a model Stirling engine on the basis of clear construction drawings. A delicacy for experienced modelers: The 'amazing model', a miniature Stirling engine consisting of beverage cans, has been running with the warmth of the human hand. Even in this technically demanding model, the construction will be described accurately by detailed construction drawings.

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

    International Nuclear Information System (INIS)

    Slaby, J.G.

    1985-01-01

    An overview of the 1985 (NASA) Lewis Research Center free-piston Stirling engine activities in support of the SP-100 Program is presented. The SP-100 program is being conducted in support of the Department of Advanced Research Projects Agency (DARPA) and the Department of Energy (DOE), and NASA. This effort is keyed on the design, fabrication, assembly, and testing of a 25 kW /SUB e/ Stirling space-power technology-feasibility demonstrator engine. Another facet of the SP-100 project covers the status of a 9000-hr goal endurance test conducted on a 2 kW /SUB e/ free-piston Stirling/ linear alternator system employing hydrostatic gas bearings. Dynamic balancing of the RE-1000 engine (a 1 kW /SUB e/ 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. New 5 kW free-piston Stirling space convertor developments

    Science.gov (United States)

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

    2008-07-01

    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 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 h. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  18. Split NMSSM with electroweak baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Demidov, S.V.; Gorbunov, D.S. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect 7a, Moscow 117312 (Russian Federation); Moscow Institute of Physics and Technology,Institutsky per. 9, Dolgoprudny 141700 (Russian Federation); Kirpichnikov, D.V. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect 7a, Moscow 117312 (Russian Federation)

    2016-11-24

    In light of the Higgs boson discovery and other results of the LHC we reconsider generation of the baryon asymmetry in the split Supersymmetry model with an additional singlet superfield in the Higgs sector (non-minimal split SUSY). We find that successful baryogenesis during the first order electroweak phase transition is possible within a phenomenologically viable part of the model parameter space. We discuss several phenomenological consequences of this scenario, namely, predictions for the electric dipole moments of electron and neutron and collider signatures of light charginos and neutralinos.

  19. Split ring containment attachment device

    International Nuclear Information System (INIS)

    Sammel, A.G.

    1996-01-01

    A containment attachment device is described for operatively connecting a glovebag to plastic sheeting covering hazardous material. The device includes an inner split ring member connected on one end to a middle ring member wherein the free end of the split ring member is inserted through a slit in the plastic sheeting to captively engage a generally circular portion of the plastic sheeting. A collar potion having an outer ring portion is provided with fastening means for securing the device together wherein the glovebag is operatively connected to the collar portion. 5 figs

  20. Splitting strings on integrable backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Vicedo, Benoit

    2011-05-15

    We use integrability to construct the general classical splitting string solution on R x S{sup 3}. Namely, given any incoming string solution satisfying a necessary self-intersection property at some given instant in time, we use the integrability of the worldsheet {sigma}-model to construct the pair of outgoing strings resulting from a split. The solution for each outgoing string is expressed recursively through a sequence of dressing transformations, the parameters of which are determined by the solutions to Birkhoff factorization problems in an appropriate real form of the loop group of SL{sub 2}(C). (orig.)

  1. Mass splitting induced by gravitation

    International Nuclear Information System (INIS)

    Maia, M.D.

    1982-08-01

    The exact combination of internal and geometrical symmetries and the associated mass splitting problem is discussed. A 10-parameter geometrical symmetry is defined in a curved space-time in such a way that it is a combination of de Sitter groups. In the flat limit it reproduces the Poincare-group and its Lie algebra has a nilpotent action on the combined symmetry only in that limit. An explicit mass splitting expression is derived and an estimation of the order of magnitude for spin-zero mesons is made. (author)

  2. MANUFACTURING AND TESTING OF A V-TYPE STIRLING ENGINE

    Directory of Open Access Journals (Sweden)

    B. Demir

    2012-01-01

    Full Text Available In this study, a V-type Stirling engine with 163 cc total swept volume was designed and manufactured. Air was used as working fluid. Performance tests were conducted at the range of 1-3 bar charge pressure and within the range of hot source temperature 700-1050 °C. Experimental results are given. Variation of engine power and torque with hot source temperature at various air charge pressure are tested. Also variation of engine torque with engine speed for different air charge pressure are tested. According to experimental analysis, the maximum engine power was obtained as 21.334 W at 1050 ˚C hot source temperature and 1.5 bars charge pressure.

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

    Science.gov (United States)

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

    2010-01-01

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

  4. Stirling engine power control and motion conversion mechanism

    Science.gov (United States)

    Marks, David T.

    1983-01-01

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

  5. Palm Power Free-Piston Stirling Engine Control Electronics

    Science.gov (United States)

    Keiter, Douglas E.; Holliday, Ezekiel

    2007-01-01

    A prototype 35We, JP-8 fueled, soldier-wearable power system for the DARPA Palm Power program has been developed and tested by Sunpower. A hermetically-sealed 42We Sunpower Free-Piston Stirling Engine (FPSE) with integral linear alternator is the prime mover for this system. To maximize system efficiency over a broad range of output power, a non-dissipative, highly efficient electronic control system which modulates engine output power by varying piston stroke and converts the AC output voltage of the FPSE into 28Vdc for the Palm Power end user, has been designed and demonstrated as an integral component of the Palm Power system. This paper reviews the current status and progress made in developing the control electronics for the Palm Power system, in addition to describing the operation and demonstrated performance of the engine controller in the context of the current JP-8 fueled Palm Power system.

  6. Free-piston Stirling component test power converter

    Science.gov (United States)

    Dochat, George; Dhar, Manmohan

    1991-01-01

    The National Aeronautics and Space Administration (NASA) has been evaluating free-piston Stirling power converters (FPSPCs) for use on a wide variety of space missions. They provide high reliability, long life, and efficient operation and can be coupled with all potential heat sources, various heat input and heat rejection systems, and various power management and distribution systems. FPSPCs can compete favorably with alternative power conversion systems over a range of hundreds of watts to megawatts. Mechanical Technology Incorporated (MTI) is developing FPSPC technology under contract to NASA Lewis Research Center and will demonstrate this technology in two full-scale power converters operating at space temperature conditions. The testing of the first of these, the component test power converter (CTPC), was initiated in Spring 1991 to evaluate mechanical operation at space operating temperatures. The CTPC design, hardware fabrication, and initial test results are reviewed.

  7. Thermal Model of a Dish Stirling Cavity-Receiver

    Directory of Open Access Journals (Sweden)

    Rubén Gil

    2015-01-01

    Full Text Available This paper presents a thermal model for a dish Stirling cavity based on the finite differences method. This model is a theoretical tool to optimize the cavity in terms of thermal efficiency. One of the main outcomes of this work is the evaluation of radiative exchange using the radiosity method; for that purpose, the view factors of all surfaces involved have been accurately calculated. Moreover, this model enables the variation of the cavity and receiver dimensions and the materials to determine the optimal cavity design. The tool has been used to study the cavity optimization regarding geometry parameters and material properties. Receiver absorptivity has been identified as the most influential property of the materials. The optimal aperture height depends on the minimum focal space.

  8. Split supersymmetry in brane models

    Indian Academy of Sciences (India)

    Type-I string theory in the presence of internal magnetic fields provides a concrete realization of split ... quantum picture of the Universe. It was then ... where the integers m, n correspond to the respective magnetic and electric charges; m is the ...

  9. VBSCan Split 2017 Workshop Summary

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Christoph Falk; et al.

    2018-01-12

    This document summarises the talks and discussions happened during the VBSCan Split17 workshop, the first general meeting of the VBSCan COST Action network. This collaboration is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

  10. Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

    Science.gov (United States)

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

    2014-01-01

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

  11. Characterization of the power and efficiency of Stirling engine subsystems

    International Nuclear Information System (INIS)

    García, D.; González, M.A.; Prieto, J.I.; Herrero, S.; López, S.; Mesonero, I.; Villasante, C.

    2014-01-01

    Highlights: • We review experimental data from a V160 engine developed for cogeneration. • We also investigate the V161 solar engine. • The possible margin of improvement is evaluated for each subsystem. • The procedure is based on similarity models and thermodynamic models. • The procedure may be of general interest for other prototypes. - Abstract: The development of systems based on Stirling machines is limited by the lack of data about the performance of the various subsystems that are located between the input and output power sections. The measurement of some of the variables used to characterise these internal subsystems presents difficulties, particularly in the working gas circuit and the drive mechanism, which causes experimental reports to rarely be comprehensive enough for analysing the whole performance of the machine. In this article, we review experimental data from a V160 engine developed for cogeneration to evaluate the general validity; we also investigate one of the most successful prototypes used in dish-Stirling systems, the V161 engine, for which a seemingly small mechanical efficiency value has been recently predicted. The procedure described in this article allows the possible margin of improvement to be evaluated for each subsystem. The procedure is based on similarity models, which have been previously developed through experimental data from very different prototypes. Thermodynamic models for the gas circuit are also considered. Deduced characteristic curves show that both prototypes have an advanced degree of development as evidenced by relatively high efficiencies for each subsystem. The analyses are examples that demonstrate the qualities of dimensionless numbers in representing physical phenomena with maximum generality and physical meaning

  12. 5-kWe Free-piston Stirling Engine Convertor

    Science.gov (United States)

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

    2008-01-01

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

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

    Science.gov (United States)

    Dhar, Manmohan

    1999-01-01

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

  14. CFD analysis of a diaphragm free-piston Stirling cryocooler

    Science.gov (United States)

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

    2016-10-01

    This paper presents a Computational Fluid Dynamics (CFD) analysis of a novel free-piston Stirling cryocooler that uses a pair of metal diaphragms to seal and suspend the displacer. The diaphragms allow the displacer to move without rubbing or moving seals. When coupled to a metal diaphragm pressure wave generator, the system produces a complete Stirling cryocooler with no rubbing parts in the working gas space. Initial modelling of this concept using the Sage modelling tool indicated the potential for a useful cryocooler. A proof-of-concept prototype was constructed and achieved cryogenic temperatures. A second prototype was designed and constructed using the experience gained from the first. The prototype produced 29 W of cooling at 77 K and reached a no-load temperature of 56 K. The diaphragm's large diameter and short stroke produces a significant radial component to the oscillating flow fields inside the cryocooler which were not modelled in the one-dimensional analysis tool Sage that was used to design the prototypes. Compared with standard pistons, the diaphragm geometry increases the gas-to-wall heat transfer due to the higher velocities and smaller hydraulic diameters. A Computational Fluid Dynamics (CFD) model of the cryocooler was constructed to understand the underlying fluid-dynamics and heat transfer mechanisms with the aim of further improving performance. The CFD modelling of the heat transfer in the radial flow fields created by the diaphragms shows the possibility of utilizing the flat geometry for heat transfer, reducing the need for, and the size of, expensive heat exchangers. This paper presents details of a CFD analysis used to model the flow and gas-to-wall heat transfer inside the second prototype cryocooler, including experimental validation of the CFD to produce a robust analysis.

  15. Comparative analysis of linear motor geometries for Stirling coolers

    Science.gov (United States)

    R, Rajesh V.; Kuzhiveli, Biju T.

    2017-12-01

    Compared to rotary motor driven Stirling coolers, linear motor coolers are characterized by small volume and long life, making them more suitable for space and military applications. The motor design and operational characteristics have a direct effect on the operation of the cooler. In this perspective, ample scope exists in understanding the behavioural description of linear motor systems. In the present work, the authors compare and analyze different moving magnet linear motor geometries to finalize the most favourable one for Stirling coolers. The required axial force in the linear motors is generated by the interaction of magnetic fields of a current carrying coil and that of a permanent magnet. The compact size, commercial availability of permanent magnets and low weight requirement of the system are quite a few constraints for the design. The finite element analysis performed using Maxwell software serves as the basic tool to analyze the magnet movement, flux distribution in the air gap and the magnetic saturation levels on the core. A number of material combinations are investigated for core before finalizing the design. The effect of varying the core geometry on the flux produced in the air gap is also analyzed. The electromagnetic analysis of the motor indicates that the permanent magnet height ought to be taken in such a way that it is under the influence of electromagnetic field of current carrying coil as well as the outer core in the balanced position. This is necessary so that sufficient amount of thrust force is developed by efficient utilisation of the air gap flux density. Also, the outer core ends need to be designed to facilitate enough room for the magnet movement under the operating conditions.

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

    Science.gov (United States)

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

    2013-01-01

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

  17. Cool covered sky-splitting spectrum-splitting FK

    Energy Technology Data Exchange (ETDEWEB)

    Mohedano, Rubén; Chaves, Julio; Falicoff, Waqidi; Hernandez, Maikel; Sorgato, Simone [LPI, Altadena, CA, USA and Madrid (Spain); Miñano, Juan C.; Benitez, Pablo [LPI, Altadena, CA, USA and Madrid, Spain and Universidad Politécnica de Madrid (UPM), Madrid (Spain); Buljan, Marina [Universidad Politécnica de Madrid (UPM), Madrid (Spain)

    2014-09-26

    Placing a plane mirror between the primary lens and the receiver in a Fresnel Köhler (FK) concentrator gives birth to a quite different CPV system where all the high-tech components sit on a common plane, that of the primary lens panels. The idea enables not only a thinner device (a half of the original) but also a low cost 1-step manufacturing process for the optics, automatic alignment of primary and secondary lenses, and cell/wiring protection. The concept is also compatible with two different techniques to increase the module efficiency: spectrum splitting between a 3J and a BPC Silicon cell for better usage of Direct Normal Irradiance DNI, and sky splitting to harvest the energy of the diffuse radiation and higher energy production throughout the year. Simple calculations forecast the module would convert 45% of the DNI into electricity.

  18. Performance characteristics of a quantum Diesel refrigeration cycle

    International Nuclear Information System (INIS)

    He Jizhou; Wang Hao; Liu Sanqiu

    2009-01-01

    The Diesel refrigeration cycle using an ideal quantum gas as the working substance is called quantum Diesel refrigeration cycle, which is different from Carnot, Ericsson, Brayton, Otto and Stirling refrigeration cycles. For ideal quantum gases, a corrected equation of state, which considers the quantum behavior of gas particles, is used instead of the classical one. The purpose of this paper is to investigate the effect of quantum gas as the working substance on the performance of a quantum Diesel refrigeration cycle. It is found that coefficients of performance of the cycle are not affected by the quantum degeneracy of the working substance, which is the same as that of the classical Diesel refrigeration cycle. However, the refrigeration load is different from those of the classical Diesel refrigeration cycle. Lastly, the influence of the quantum degeneracy on the performance characteristics of the quantum Diesel refrigeration cycle operated in different temperature regions is discussed

  19. No money printing machine. The market for cogeneration units with a Stirling engine begins to increase; Keine Gelddruckmaschinen. Markt fuer Stirling-KWK-Geraete kommt in Bewegung

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Wolfgang

    2012-10-15

    The serial production of micro combined heat and power units with a Stirling engine is started. However, it is becoming apparent, that from economic reasons units of the 1-kW{sub el.}-class designed for single-family houses and two-family houses are increasingly used as a base load unit in multi-family houses and small trades.

  20. Fort Huachuca to Benefit from New Solar Technology: Dish-Stirling System Couples Solar Power with Engine to Generate Electricity

    National Research Council Canada - National Science Library

    1995-01-01

    ... in partnership with industry. A prototype dish-Stirling solar system, which consists of a large dish of solar concentrators and a Stirling heat engine, will be installed at Fort Huachuca in July and should be in operation about two weeks later...

  1. Emotional and Psychological Well-Being in Children: The Development and Validation of the Stirling Children's Well-Being Scale

    Science.gov (United States)

    Liddle, Ian; Carter, Greg F. A.

    2015-01-01

    The Stirling Children's Well-being Scale (SCWBS) was developed by the Stirling Council Educational Psychology Service (UK) as a holistic, positively worded measure of emotional and psychological well-being in children aged eight to 15 years. Drawing on current theories of well-being and Positive Psychology, the aim was to provide a means of…

  2. Geometrical Applications of Split Octonions

    Directory of Open Access Journals (Sweden)

    Merab Gogberashvili

    2015-01-01

    Full Text Available It is shown that physical signals and space-time intervals modeled on split-octonion geometry naturally exhibit properties from conventional (3 + 1-theory (e.g., number of dimensions, existence of maximal velocities, Heisenberg uncertainty, and particle generations. This paper demonstrates these properties using an explicit representation of the automorphisms on split-octonions, the noncompact form of the exceptional Lie group G2. This group generates specific rotations of (3 + 4-vector parts of split octonions with three extra time-like coordinates and in infinitesimal limit imitates standard Poincare transformations. In this picture translations are represented by noncompact Lorentz-type rotations towards the extra time-like coordinates. It is shown how the G2 algebra’s chirality yields an intrinsic left-right asymmetry of a certain 3-vector (spin, as well as a parity violating effect on light emitted by a moving quantum system. Elementary particles are connected with the special elements of the algebra which nullify octonionic intervals. Then the zero-norm conditions lead to free particle Lagrangians, which allow virtual trajectories also and exhibit the appearance of spatial horizons governing by mass parameters.

  3. Design, Analysis and Optimization of a Solar Dish/Stirling System

    Directory of Open Access Journals (Sweden)

    Seyyed Danial Nazemi

    2016-02-01

    Full Text Available In this paper, a mathematical model by which the thermal and physical behavior of a solar dish/Stirling system was investigated, then the system was designed, analysed and optimized. In this regard, all of heat losses in a dish/Stirling system were calculated, then, the output net-work of the Stirling engine was computed, and accordingly, the system efficiency was worked out. These heat losses include convection and conduction heat losses, radiation heat losses by emission in the cavity receiver, reflection heat losses of solar energy in the parabolic dish, internal and external conduction heat losses, energy dissipation by pressure drops, and energy losses by shuttle effect in displacer piston in the Stirling engine. All of these heat losses in the parabolic dish, cavity receiver and Stirling engine were calculated using mathematical modeling in MatlabTM software. For validation of the proposed model, a 10 kW solar dish/Stirling system was designed and the simulation results were compared with the Eurodish system data with a reasonable degree of agreement. This model is used to investigate the effect of geometric and thermodynamic parameters including the aperture diameter of the parabolic dish and the cavity receiver, and the pressure of the compression space of the Stirling engine, on the system performance. By using the PSO method, which is an intelligent optimization technique, the total design was optimized and the optimal values of decision-making parameters were determined. The optimization has been done in two scenarios. In the first scenario, the optimal value of each designed parameter has been changed when the other parameters are equal to the designed case study parameters. In the second scenario, all of parameters were assumed in their optimal values. By optimization of the modeled dish/Stirling system, the total efficiency of the system improved to 0.60% in the first scenario and it increased from 21.69% to 22.62% in the second

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

    International Nuclear Information System (INIS)

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

    1998-01-01

    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

  5. Thermodynamic consideration on the constitution of multi-thermochemical water splitting process

    International Nuclear Information System (INIS)

    Tagawa, Hiroaki

    1976-03-01

    The multi-thermochemical water splitting cycle comprises individual chemical reactions which are generalized as hydrolysis, hydrogen generation, oxygen generation and regeneration of the circulating materials. The circulating agents are required for the constitution of the cycle, but the guiding principle of selecting them is not available yet. In the present report, thermodynamic properties, especially Gibbs free energies for formation, of the agents are examined as a function of temperature. Oxides, sulfo-oxides, chlorides, bromides and iodides are chosen as the compounds. The chemical reactions for hydrolysis, hydrogen generation and oxygen generation are reviewed in detail. The general formulas for the three step splitting cycle are represented with discussion. (auth.)

  6. 2-Photon tandem device for water splitting

    DEFF Research Database (Denmark)

    Seger, Brian; Castelli, Ivano Eligio; Vesborg, Peter Christian Kjærgaard

    2014-01-01

    Within the field Of photocatalytic water splitting there are several strategies to achieve the goal of efficient and cheap photocatalytic water splitting. This work examines one particular strategy by focusing on monolithically stacked, two-photon photoelectrochemical cells. The overall aim...... for photocatalytic water splitting by using a large bandgap photocathode and a low bandgap photoanode with attached protection layers....

  7. Performance optimum analysis of an irreversible molten carbonate fuel cell–Stirling heat engine hybrid system

    International Nuclear Information System (INIS)

    Chen, Liwei; Zhang, Houcheng; Gao, Songhua; Yan, Huixian

    2014-01-01

    A new hybrid system mainly consists of a molten carbonate fuel cell (MCFC) and a Stirling heat engine is established, where the Stirling heat engine is driven by the high-quality waste heat generated in the MCFC. Based on the electrochemistry and non-equilibrium thermodynamics, analytical expressions for the efficiency and power output of the hybrid system are derived by taking various irreversible losses into account. It shows that the performance of the MCFC can be greatly enhanced by coupling a Stirling heat engine to further convert the waste heat for power generation. By employing numerical calculations, not only the influences of multiple irreversible losses on the performance of the hybrid system are analyzed, but also the impacts of some operating conditions such as the operating temperature, input gas compositions and operating pressure on the performance of the hybrid system are also discussed. The investigation method in the present paper is feasible for some other similar energy conversion systems as well. - Highlights: • A model of MCFC–Stirling heat engine hybrid system is established. • Analytical expressions for the efficiency and power output are derived. • MCFC performance can be greatly enhanced by coupling a Stirling heat engine. • Effects of some operating conditions on the performance are discussed. • Optimum operation regions are subdivided by multi-objective optimization method

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  9. An analysis of beta type Stirling engine with rhombic drive mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Shendage, D.J.; Kedare, S.B. [Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076 (India); Bapat, S.L. [Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076 (India)

    2011-01-15

    Stirling engine system is one of the options for electrifying a remote community not serviceable by the grid, which can operate on energy input in the form of heat. Major hurdle for the wide-spread usage of rhombic drive beta type Stirling engine is complexity of the drive and requirement of tight tolerances for its proper functioning. However, if the operating and geometrical constraints of the system are accounted for, different feasible design options can be identified. In the present work, various aspects that need to be considered at different decision making stages of the design and development of a Stirling engine are addressed. The proposed design methodology can generate and evaluate a range of possible design alternatives which can speed up the decision making process and also provide a clear understanding of the system design considerations. The present work is mainly about the design methodology for beta type Stirling engine and the optimization of phase angle, considering the effect of overlapping volume between compression and expansion spaces. It is also noticed that variation of compression space volume with phase angle remains sinusoidal for any phase difference. The aim of the present work is to find a feasible solution which should lead to a design of a single cylinder, beta type Stirling engine of 1.5 kW{sub e} capacity for rural electrification. (author)

  10. Dynamic model of Stirling engine crank mechanism with connected electric generator

    Directory of Open Access Journals (Sweden)

    Vlach R.

    2009-06-01

    Full Text Available This paper treats of a numerical dynamic model of Stirling engine crank mechanism. The model is included in the complex model of combined heat and power unit. The unit is composed of the Stirling engine and of attached three-phase synchronous generator. This generator should start the Stirling engine in motor mode as well. It is necessary to combine the crank shaft dynamic model and the complete thermal model of Stirling engine for simulations and analyses of engine run. Our aim is to create a dynamics model which takes into account the parameters of crankshaft, piston rods, pistons, and attached generator. For unit working, the electro-mechanical behaviour of generator is also important. That is why we experimentally verified the parameters of generator. The measured characteristics are used in a complex model of heat and power unit. Moreover, it is also possible to determine the Stirling engine torque by the help of these electro-mechanical characteristics. These values can be used e. g. for determination of optimal engine working point or for unit control.

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

    Science.gov (United States)

    Shaltens, Richard K.; Schreiber, Jeffrey G.

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

  12. Stirling engine based micro co-generation system for single households

    Energy Technology Data Exchange (ETDEWEB)

    Ribberink, H.; Zutt, S.; Rabou, L.; Beckers, G. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands); Baijens, K.; Luttikholt, J. [Atag Verwarming BV (Netherlands)

    2000-07-01

    This paper describes the progress made in the ENATEC development program for a free piston Stirling engine based micro co-generation system that serves the supply of up to 1 kW{sub e} and up to 24 kW heat for domestic heating and/or for hot tap water production for single households at overall system efficiencies of 96%: Experiments show that the free piston Stirling engines from Stirling Technology Company run very reliably and controllably, and that the efficiency targets for the 1 kW{sub e} micro co-generation system are feasible. A ceramic foam burner with good heat transfer characteristics and low NOx emissions was developed. A demonstration micro co-generation unit was built and successfully presented. A 1 kW{sub e} free piston Stirling engine for the European market was developed. High efficiencies at full load and at part load, low emissions, low noise, and minimum maintenance make the Stirling engine based micro co-generation system an attractive candidate for the next generation of domestic boilers in Europe. (orig.)

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

    Science.gov (United States)

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

    2008-01-01

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

  14. Operational data and thermodynamic modeling of a Stirling-dish demonstration installation in desert conditions

    Science.gov (United States)

    Nilsson, Martin; Jamot, Jakob; Malm, Tommy

    2017-06-01

    To field test its Stirling-dish unit, Cleanergy AB of Sweden in Q1 2015 built a ten unit demo park in Dubai. The first STE (Solar Thermal Energy) generation of its Stirling genset, the C11S, had at its core an 11 kWel Stirling engine/generator combination. The genset was mated with a parabolic concentrator developed for the genset by a supplier. Local weather conditions in Dubai provide opportunities to test performance in an environment with high insolation and high ambient temperature. In addition, the conditions in Dubai are windy, salty, humid and dusty, historically challenging for solar technologies [1]. In Q1 2016 one of the C11S Stirling-dish units was replaced by the first prototype of Cleanergy's second generation Stirling genset, the Sunbox, and an in-house developed parabolic concentrator. Operational data from field testing during the spring of 2016 are presented and discussed and show the large performance improvement achieved with the Sunbox unit.

  15. Achievement report for fiscal 1983 on Sunshine Program-entrusted research and development. Research and development of water-splitting systems using thermochemical, photochemical, and electrochemical mixed cycle; 1983 nendo netsu kagaku, hikari kagaku, denki kagaku konsei cycle ni yoru suibunkai no kenkyu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1984-03-01

    The report covers the outcome of a basic study of the splitting of water using photochemical reaction. The behavior of iron ions and iodine ions is important in the photochemical reaction in the phosphoric acid and in the energy exchange that follows, and the characteristics of iodine ions are investigated in detail. Since the response of a commercially available iodine ion electrode is slow in a strong phosphoric acid solution, a silver/silver iodide electrode is experimentally built, and is used in the investigation of the iodine ion activity coefficient. In the investigation, it is indicated that more energy is accumulated when temperature or concentration is higher. In the case where sunlight is used as the light source for photochemical reaction, it is necessary to perform optimal control in compliance with fluctuation in sunlight intensity. In the study, fluctuation in sunlight intensity is assumed to be composed of step waves, pulse waves, and sinusoidal waves, and a result of digital simulation is obtained by using a modelling method for control. For the convenience of computation, the number of cell division is set at approximately five, when the solution flow responsiveness and energy conversion utilization factor are found to be excellent. (NEDO)

  16. Ten Year Operating Test Results and Post-Test Analysis of a 1/10 Segment Stirling Sodium Heat Pipe, Phase III

    Science.gov (United States)

    Rosenfeld, John, H; Minnerly, Kenneth, G; Dyson, Christopher, M.

    2012-01-01

    High-temperature heat pipes are being evaluated for use in energy conversion applications such as fuel cells, gas turbine re-combustors, Stirling cycle heat sources; and with the resurgence of space nuclear power both as reactor heat removal elements and as radiator elements. Long operating life and reliable performance are critical requirements for these applications. Accordingly, long-term materials compatibility is being evaluated through the use of high-temperature life test heat pipes. Thermacore, Inc., has carried out a sodium heat pipe 10-year life test to establish long-term operating reliability. Sodium heat pipes have demonstrated favorable materials compatibility and heat transport characteristics at high operating temperatures in air over long time periods. A representative one-tenth segment Stirling Space Power Converter heat pipe with an Inconel 718 envelope and a stainless steel screen wick has operated for over 87,000 hr (10 yr) at nearly 700 C. These life test results have demonstrated the potential for high-temperature heat pipes to serve as reliable energy conversion system components for power applications that require long operating lifetime with high reliability. Detailed design specifications, operating history, and post-test analysis of the heat pipe and sodium working fluid are described.

  17. Performance degradation of space Stirling cryocoolers due to gas contamination

    Science.gov (United States)

    Liu, Xin-guang; Wu, Yi-nong; Yang, Shao-hua; Zhang, Xiao-ming; Lu, Guo-hua; Zhang, Li

    2011-08-01

    With extensive application of infrared detective techniques, Stirling cryocoolers, used as an active cooling source, have been developed vigorously in China. After the cooler's cooling performance can satisfy the mission's request, its reliability level is crucial for its application. Among all the possible failure mechanisms, gas contamination has been found to be the most notorious cause of cooler's performance degradation by failure analyses. To analyze the characteristic of gas contamination, some experiments were designed and carried out to quantitatively analyze the relationship between failure and performance. Combined with the test results and the outgassing characteristic of non-metal materials in the cryocooler, a degradation model of cooling performance was given by T(t)=T0+A[1-exp(-t/B)] under some assumptions, where t is the running time, T is the Kelvin cooling temperature, and T0, A, B are model parameters, which can be given by the least square method. Here T0 is the fitting initial cooling temperature, A is the maximum range of performance degradation, and B is the time dependent constant of degradation. But the model parameters vary when a cryocooler is running at different cooling temperature ranges, or it is treated by different cleaning process. In order to verify the applicability of the degradation model, data fit analysis on eight groups of cooler's lifetime test was carried out. The final work indicated this model fit well with the performance degradation of space Stirling cryocoolers due to gas contamination and this model could be used to predict or evaluation the cooler's lifetime. Gaseous contamination will not arouse severe performance degradation until the contaminants accumulate to a certain amount, but it could be fatal when it works. So it is more serious to the coolers whose lifetime is more than 10,000 h. The measures taken to control or minimize its damage were discussed as well. To the long-life cryocooler, internal materials

  18. Innovative wedge axe in making split firewood

    International Nuclear Information System (INIS)

    Mutikainen, A.

    1998-01-01

    Interteam Oy, a company located in Espoo, has developed a new method for making split firewood. The tools on which the patented System Logmatic are based are wedge axe and cylindrical splitting-carrying frame. The equipment costs about 495 FIM. The block of wood to be split is placed inside the upright carrying frame and split in a series of splitting actions using the innovative wedge axe. The finished split firewood remains in the carrying frame, which (as its name indicates) also serves as the means for carrying the firewood. This innovative wedge-axe method was compared with the conventional splitting of wood using an axe (Fiskars -handy 1400 splitting axe costing about 200 FIM) in a study conducted at TTS-Institute. There were eight test subjects involved in the study. In the case of the wedge-axe method, handling of the blocks to be split and of the finished firewood was a little quicker, but in actual splitting it was a little slower than the conventional axe method. The average productivity of splitting the wood and of the work stages related to it was about 0.4 m 3 per effective hour in both methods. The methods were also equivalent of one another in terms of the load imposed by the work when measured in terms of the heart rate. As regards work safety, the wedge-axe method was superior to the conventional method, but the continuous striking action and jolting transmitted to the arms were unpleasant (orig.)

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

    Science.gov (United States)

    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.

  20. Mechanical Engineering Practice – using a simple Stirling engine as case

    DEFF Research Database (Denmark)

    Meyer, Knud Erik

    2011-01-01

    The first technical course that students in mechanical engineering take at the Technical University of Denmark is called “Mechanical Engineering Practice”. We have used a simple Stirling engine as a design-implement project. Students were asked to design and build a heat engine using materials....... The Stirling engine worked well in the drawing assignments. The Stirling engine also served as illustration of coming courses in mechanical engineering. The resulting engines had large variations in their design and most groups succeeded in building a functioning engine. However, achieved efficiencies were...... obtained by their own means and were competing on achieving the highest efficiency. We added an extra dimension to the project by making detailed measurements of the pressure variation to check simple thermodynamic models of the engine. The course had integrated lessons in sketching and technical drawing...