Annual energy balances of CHP-units supplying households; Jahresenergiebilanzen von KWK-Anlagen zur Hausenergieversorgung

Energy Technology Data Exchange (ETDEWEB)

Geiger, B.; Muehlbacher, H. [Technische Univ. Muenchen (Germany). Lehrstuhl fuer Energiewirtschaft und Anwendungstechnik

2008-07-01

A method to balance CHP-units for use in households on an annual basis has been developed. Seasonal as well as intraday fluctuations of the CHP-units are accounted for in the model. The results of this new method were validated in a test facility for certain days. Together with experimentally obtained data from a CHP-unit, the potential for technical improvements and a more favourable operational mode can be derived from the model. (orig.)

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.

Testing of a Stirling engine for heat + power cogeneration; Test eines Stirlingmotors zur Kraft-Waerme-Kopplung

Energy Technology Data Exchange (ETDEWEB)

Kramer, M.; Heinen, J. [RWE Energy AG, Essen (Germany)

2007-01-15

As part of a technology evaluation of distributed energy generators, RWE Energy AG extensively tested a micro combined heat and power appliance, powered by a Stirling engine developed by the British firm Microgen Energy Limited. Microgen Energy Limited is a specialist in micro combined heat and power (microCHP) based on unique Free-Piston Stirling generator technology Microgen is working with leading appliance manufacturers to integrate its core technology into a range of innovative microCHP products. The investigations concentrated on the determination of capacity, efficiency and emissions, the grid connection and behaviour at start-up and under varying loads. This article summarises the results of the tests and gives an overview of micro-CHP technologies (CHP=combined heat and power) and their possible significance to the market in the future. (orig.)

Development of a pellet boiler with Stirling engine for m-CHP domestic application

Energy Technology Data Exchange (ETDEWEB)

Crema, Luigi; Alberti, Fabrizio; Bertaso, Alberto; Bozzoli, Alessandro [Fondazione Bruno Kessler (FBK), Povo, Trento (IT). Renewable Energies and Environmental Technologies Unit (REET)

2011-12-15

A new sustainable technology has been designed by Fondazione Bruno Kessler through its unit Renewable Energies and Environmental Technologies. This technology is realized integrating in a single system (1) a Stirling engine (mRT-1K) from a pre-engineering design of Allan J. Organ; (2) a micro-heat exchanger technology, to reduce the net transfer unit deficit on the hot side of the heat engine; (3) a customized pellet boiler, able to extract electrical and thermal power; and (4) a customized hydraulic circuit, connecting the cool side of the Stirling engine and the heat generation on the second section of the pellet boiler. The objective of this paper was to present a new technology for the micro-cogeneration of energy at a distributed level able to be integrated in domestic dwellings. Most part of the available biomass is used in buildings for the generation of thermal power for indoor heating and, in minor cases, for hot sanitary water. In the Province of Trento, 88% of the biomass is used for this purpose. The full system is actually under integration for the test phase and not yet tested. The first tests on the single components have confirmed preliminary results on the Stirling engine with respect to the tolerances, pressurization, and proper integration of the electrical generator-driven control system. The pellet boiler has been tested separately, confirming an overall thermal efficiency of 90%. (orig.)

Micro-CHP systems for residential applications

International Nuclear Information System (INIS)

Paepe, Michel de; D'Herdt, Peter; Mertens, David

2006-01-01

Micro-CHP systems are now emerging on the market. In this paper, a thorough analysis is made of the operational parameters of 3 types of micro-CHP systems for residential use. Two types of houses (detached and terraced) are compared with a two storey apartment. For each building type, the energy demands for electricity and heat are dynamically determined. Using these load profiles, several CHP systems are designed for each building type. Data were obtained for two commercially available gas engines, two Stirling engines and a fuel cell. Using a dynamic simulation, including start up times, these five system types are compared to the separate energy system of a natural gas boiler and buying electricity from the grid. All CHP systems, if well sized, result in a reduction of primary energy use, though different technologies have very different impacts. Gas engines seem to have the best performance. The economic analysis shows that fuel cells are still too expensive and that even the gas engines only have a small internal rate of return (<5%), and this only occurs in favourable economic circumstances. It can, therefore, be concluded that although the different technologies are technically mature, installation costs should at least be reduced by 50% before CHP systems become interesting for residential use. Condensing gas boilers, now very popular in new homes, prove to be economically more interesting and also have a modest effect on primary energy consumption

Optimal design of CHP-based microgrids: Multiobjective optimisation and life cycle assessment

International Nuclear Information System (INIS)

Zhang, Di; Evangelisti, Sara; Lettieri, Paola; Papageorgiou, Lazaros G.

2015-01-01

As an alternative to current centralised energy generation systems, microgrids are adopted to provide local energy with lower energy expenses and gas emissions by utilising distributed energy resources (DER). Several micro combined heat and power technologies have been developed recently for applications at domestic scale. The optimal design of DERs within CHP-based microgrids plays an important role in promoting the penetration of microgrid systems. In this work, the optimal design of microgrids with CHP units is addressed by coupling environmental and economic sustainability in a multi-objective optimisation model which integrates the results of a life cycle assessment of the microgrids investigated. The results show that the installation of multiple CHP technologies has a lower cost with higher environmental saving compared with the case when only a single technology is installed in each site, meaning that the microgrid works in a more efficient way when multiple technologies are selected. In general, proton exchange membrane (PEM) fuel cells are chosen as the basic CHP technology for most solutions, which offers lower environmental impacts at low cost. However, internal combustions engines (ICE) and Stirling engines (SE) are preferred if the heat demand is high. - Highlights: • Optimal design of microgrids is addressed by coupling environmental and economic aspects. • An MILP model is formulated based on the ε-constraint method. • The model selects a combination of CHP technologies with different technical characteristics for optimum scenarios. • The global warming potential (GWP) and the acidification potential (AP) are determined. • The output of LCA is used as an input for the optimisation model

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...

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.

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

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.

Development of a Transient Model of a Stirling-Based CHP System

Directory of Open Access Journals (Sweden)

Antón Cacabelos

2013-06-01

Full Text Available Although the Stirling engine was invented in 1816, this heat engine still continues to be investigated due to the variety of energy sources that can be used to power it (e.g., solar energy, fossil fuels, biomass, and geothermal energy. To study the performance of these machines, it is necessary to develop and simulate models under different operating conditions. In this paper, we present a one-dimensional dynamic model based on components from Trnsys: principally, a lumped mass and a heat exchanger. The resulting model is calibrated using GenOpt. Furthermore, the obtained model can be used to simulate the machine both under steady-state operation and during a transient response. The results provided by the simulations are compared with data measured in a Stirling engine that has been subjected to different operating conditions. This comparison shows good agreement, indicating that the model is an appropriate method for transient thermal simulations. This new proposed model requires few configuration parameters and is therefore easily adaptable to a wide range of commercial models of Stirling engines. A detailed analysis of the system results reveals that the power is directly related to the difference of temperatures between the hot and cold sources during the transient and steady-state processes.

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.

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...

Experimental characterization, modeling and simulation of a wood pellet micro-combined heat and power unit used as a heat source for a residential building

Energy Technology Data Exchange (ETDEWEB)

Thiers, Stephane; Aoun, Bernard; Peuportier, Bruno [MINES ParisTech, CEP - Centre Energetique et Procedes, 60 Boulevard St Michel, 75272 Paris Cedex 06 (France)

2010-06-15

Cogeneration provides heat and power in a more efficient way than separate production. Micro-cogeneration (micro-CHP) is an emerging solution for the improvement of energy and environmental assessments of residential buildings. A wood pellet Stirling engine micro-CHP unit has been studied in order to characterize its annual performance when integrated to a building. First, through a test bench experiment, both transient and steady state behaviors of the micro-CHP unit have been characterized and modeled. Then a more complete model representing a hot water and heating system including the micro-CHP unit and a stratified storage tank has been carried out. This model has been coupled to a building model. A sensitivity analysis by simulation shows that the dimensioning of different elements of the system strongly influences its global energy performance. (author)

Thermodynamic and Thermoeconomic investigation of an Integrated Gasification SOFC and Stirling Engine

DEFF Research Database (Denmark)

Rokni, Masoud

2013-01-01

Thermodynamic and thermoeconomic investigation of a small scale Integrated Gasification Solid Oxide Fuel Cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120kW have been performed. Woodchips are used as gasification feedstock to produce syngas which......-product and the cost of hot water was found to be 0.0214$/kWh. When compared to other renewable systems at similar scale, it shows that if both SOFC and Stirling engine technology emerges enter commercialization phase, then they can deliver electricity at a cost rate which is competitive with corresponding renewable...

Optimal integrated sizing and planning of hubs with midsize/large CHP units considering reliability of supply

International Nuclear Information System (INIS)

Moradi, Saeed; Ghaffarpour, Reza; Ranjbar, Ali Mohammad; Mozaffari, Babak

2017-01-01

Highlights: • New hub planning formulation is proposed to exploit assets of midsize/large CHPs. • Linearization approaches are proposed for two-variable nonlinear CHP fuel function. • Efficient operation of addressed CHPs & hub devices at contingencies are considered. • Reliability-embedded integrated planning & sizing is formulated as one single MILP. • Noticeable results for costs & reliability-embedded planning due to mid/large CHPs. - Abstract: Use of multi-carrier energy systems and the energy hub concept has recently been a widespread trend worldwide. However, most of the related researches specialize in CHP systems with constant electricity/heat ratios and linear operating characteristics. In this paper, integrated energy hub planning and sizing is developed for the energy systems with mid-scale and large-scale CHP units, by taking their wide operating range into consideration. The proposed formulation is aimed at taking the best use of the beneficial degrees of freedom associated with these units for decreasing total costs and increasing reliability. High-accuracy piecewise linearization techniques with approximation errors of about 1% are introduced for the nonlinear two-dimensional CHP input-output function, making it possible to successfully integrate the CHP sizing. Efficient operation of CHP and the hub at contingencies is extracted via a new formulation, which is developed to be incorporated to the planning and sizing problem. Optimal operation, planning, sizing and contingency operation of hub components are integrated and formulated as a single comprehensive MILP problem. Results on a case study with midsize CHPs reveal a 33% reduction in total costs, and it is demonstrated that the proposed formulation ceases the need for additional components/capacities for increasing reliability of supply.

Large-Scale Combined Heat and Power (CHP) Generation at Loviisa Nuclear Power Plant Unit 3

International Nuclear Information System (INIS)

Bergroth, N.

2010-01-01

Fortum has applied for a Decision in Principle concerning the construction of a new nuclear power plant unit (Loviisa 3) ranging from 2800-4600 MWth at its site located at the southern coast of Finland. An attractive alternative investigated is a co-generation plant designed for large-scale district heat generation for the Helsinki metropolitan area that is located approximately 75 km west of the site. The starting point is that the district heat generation capacity of 3 unit would be around 1 000 MWth.The possibility of generating district heat for the metropolitan area by Loviisa's two existing nuclear power plant units was investigated back in the 1980s, but it proved unpractical at the time. With the growing concern of the climate change and the subsequent requirements on heat and power generation, the idea is much more attractive today, when recognising its potential to decrease Finland's carbon dioxide emissions significantly. Currently the district heat generation in metropolitan area is based on coal and natural gas, producing some five to seven million tonnes of carbon dioxide emissions annually. Large-scale combined heat and power (CHP) generation at the 3 unit could cut this figure by up to four million tonnes. This would decrease carbon dioxide emissions by as much as six percent. In addition, large-scale CHP generation would increase the overall efficiency of the new unit significantly and hence, reduce the environmental impact on the local marine environment by cutting heat discharges into the Gulf of Nuclear energy has been used for district heating in several countries both in dedicated nuclear heating plants and in CHP generation plants. However, the heat generation capacity is usually rather limited, maximum being around 250 MWth per unit. Set against this, the 3 CHP concept is much more ambitious, not only because of the much larger heat generation output envisaged, but also because the district heating water would have to be transported over a

Design and analysis of permanent magnet moving coil type generator used in a micro-CHP generation system

Science.gov (United States)

Oros Pop, Susana Teodora; Berinde, Ioan; Vadan, Ioan

2015-12-01

This paper presents the design and analysis of a permanent magnet moving coil type generator driven by a free piston Stirling engine. This assemble free piston Stirling engine - permanent magnet moving coil type generator will be used in a combined heat and power (CHP) system for producing heat and power in residential area. The design procedure for moving coil type linear generator starts from the rated power imposed and finally uses the Faraday law of induction. The magneto-static magnetic field generated by permanent magnets is analyzed by means of Reluctance method and Finite Element Method in order to evaluate the magnetic flux density in the air gap, which is a design data imposed in the design stage, and the results are compared.

Kyoto commitments: CHP will help the UK

International Nuclear Information System (INIS)

Knowles, Michael

1998-01-01

In order to meet the United Kingdom's targets for carbon dioxide emissions reduction, agreed at the Kyoto Summit, the UK Government is promoting the use of combined heat and power (CHP) plants. Such schemes need to offer over 70% efficiency, have on-site or nearby heat uses, and allow flexibility for the export of electricity where this is appropriate. Electricity trading arrangements will need to be re-organised in line with similar commodities, in order to facilitate and promote the growth of CHP and renewable energy schemes. Financial incentives and regulation of electricity prices will also contribute to the promotion of CHP schemes, ultimately leading to reduced CO 2 pollution as a result of the growth in the UK's CHP capacity. (UK)

Modelling the Italian household sector at the municipal scale: Micro-CHP, renewables and energy efficiency

International Nuclear Information System (INIS)

Comodi, Gabriele; Cioccolanti, Luca; Renzi, Massimiliano

2014-01-01

This study investigates the potential of energy efficiency, renewables, and micro-cogeneration to reduce household consumption in a medium Italian town and analyses the scope for municipal local policies. The study also investigates the effects of tourist flows on town's energy consumption by modelling energy scenarios for permanent and summer homes. Two long-term energy scenarios (to 2030) were modelled using the MarkAL-TIMES generator model: BAU (business as usual), which is the reference scenario, and EHS (exemplary household sector), which involves targets of penetration for renewables and micro-cogeneration. The analysis demonstrated the critical role of end-use energy efficiency in curbing residential consumption. Cogeneration and renewables (PV (photovoltaic) and solar thermal panels) were proven to be valuable solutions to reduce the energetic and environmental burden of the household sector (−20% in 2030). Because most of household energy demand is ascribable to space-heating or hot water production, this study finds that micro-CHP technologies with lower power-to-heat ratios (mainly, Stirling engines and microturbines) show a higher diffusion, as do solar thermal devices. The spread of micro-cogeneration implies a global reduction of primary energy but involves the internalisation of the primary energy, and consequently CO 2 emissions, previously consumed in a centralised power plant within the municipality boundaries. - Highlights: • Energy consumption in permanent homes can be reduced by 20% in 2030. • High efficiency appliances have different effect according to their market penetration. • Use of electrical heat pumps shift consumption from natural gas to electricity. • Micro-CHP entails a global reduction of energy consumption but greater local emissions. • The main CHP technologies entering the residential market are Stirling and μ-turbines

Power to the people

Energy Technology Data Exchange (ETDEWEB)

Lawton, G.

2002-03-02

The Harrison family from Chester in north-west England are currently testing a 'personal' combined heat and power (CHP) plant in their garage. The CHP plant, which was supplied by the New Zealand-based company WhisperTech, produces electricity and provides space heating and hot water. The floor-mounted WhisperTech unit produces about 6 kW of heat and 1 kW of electricity. A similar wall-mounted unit developed by BG Group produces up to 15 kW of heat and 1.1 kilowatt of electricity. These personal CHP plants are based on Stirling engines built using advanced materials that can cope with the high temperatures necessary for the efficient operation required to achieve energy savings compared with conventional boilers. Some 20 WhisperTech units and 12 BG Group units have been installed in UK homes. Units have also been fitted in houses in the Netherlands. The advantages of personal CHP systems, the operation of Stirling engines and the need to remain connected to the mains are explained.

Thermodynamic and thermoeconomic analysis of a system with biomass gasification, solid oxide fuel cell (SOFC) and Stirling engine

DEFF Research Database (Denmark)

Rokni, Masoud

2014-01-01

Thermodynamic and thermoeconomic investigations of a small-scale integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120kWe have been performed. Woodchips are used as gasification feedstock to produce syngas......Wh. Furthermore, hot water is considered as a by-product, and the cost of hot water is found to be 0.0214$/kWh. When compared to other renewable systems of similar scales, this result shows that if both SOFC and Stirling engine technology enter the commercialization phase, then they can deliver electricity...

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.)

Optimal designs of small CHP plants in a market with fluctuating electricity prices

International Nuclear Information System (INIS)

Lund, H.; Andersen, A.N.

2005-01-01

Combined Heat and Power production (CHP) are essential for implementation of the climate change response objectives in many countries. In an introduction period, small CHP plants have typically been offered fixed electricity prices, but in many countries, such pricing conditions are now being replaced by spot market prices. Consequently, new methodologies and tools for the optimisation of small CHP plant designs are needed. The small CHP plants in Denmark are already experienced in optimising their electricity production against the triple tariff, which has existed for almost 10 years. Consequently, the CHP plants have long term experience in organising when to switch on and off the CHP units in order to optimise their profit. Also, the CHP owners have long term experience in designing their plants. For instance, small CHP plants in Denmark have usually invested in excess capacity on the CHP units in combination with heat storage capacity. Thereby, the plants have increased their performance in order to optimise revenues. This paper presents the Danish experience with methodologies and software tools, which have been used to design investment and operation strategies for almost all small CHP plants in Denmark during the decade of the triple tariff. Moreover, the changes in such methodologies and tools in order to optimise performance in a market with fluctuating electricity prices are presented and discussed

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

Thermodynamic and thermoeconomic analysis of a system with biomass gasification, solid oxide fuel cell (SOFC) and Stirling engine

International Nuclear Information System (INIS)

Rokni, Masoud

2014-01-01

Thermodynamic and thermoeconomic investigations of a small-scale integrated gasification solid oxide fuel cell (SOFC) and Stirling engine for combined heat and power (CHP) with a net electric capacity of 120 kW e have been performed. Woodchips are used as gasification feedstock to produce syngas, which is then utilized to feed the anode side of the SOFC stacks. A thermal efficiency of 0.424 LHV (lower heating value) for the plant is found to use 89.4 kg/h of feedstock to produce the above mentioned electricity. Thermoeconomic analysis shows that the production price of electricity is 0.1204 $/kWh. Furthermore, hot water is considered as a by-product, and the cost of hot water is found to be 0.0214 $/kWh. When compared to other renewable systems of similar scales, this result shows that if both SOFC and Stirling engine technology enter the commercialization phase, then they can deliver electricity at a cost that is competitive with the corresponding renewable systems of the same size. - Highlights: • A 120 kW e integrated gasification SOFC–Stirling CHP is presented. • Effect of important parameters on plant characteristic and economy are studied. • A modest thermal efficiency of 0.41 is found after thermoeconomic optimization. • Reducing stack numbers cuts cost of electricity at expense of thermal efficiency. • The plant cost is estimated to be about 3433 $/kW when disposal costs are neglected

Micro-CHP Systems for Residential Applications

Energy Technology Data Exchange (ETDEWEB)

Timothy DeValve; Benoit Olsommer

2007-09-30

homeowner. In its proposed embodiment, the system has a 2kW prime mover integrated to a furnace platform. The second version is a Micro-Trigen system with heating, cooling and power. It has the same Micro-Cogen platform integrated with a 14kW thermally activated chiller. A Stirling engine is suggested as a promising path for the prime mover. A LiBr absorption chiller is today's best technology in term of readiness level. Paybacks are acceptable for the Micro-Cogen version. However, there is no clear economically viable path for a Micro-Trigen version with today's available technology. This illustrates the importance of financial incentives to home owners in the initial stage of micro-CHP commercialization. It will help create the necessary conditions of volume demand to start transitioning to mass-production and cost reduction. Incentives to the manufacturers will help improve efficiency, enhance reliability, and lower cost, making micro-CHP products more attractive. Successful development of a micro-CHP system for residential applications has the potential to provide significant benefits to users, customers, manufacturers, and suppliers of such systems and, in general, to the nation as a whole. The benefits to the ultimate user are a comfortable and healthy home environment at an affordable cost, potential utility savings, and a reliable supply of energy. Manufacturers, component suppliers, and system integrators will see growth of a new market segment for integrated energy products. The benefits to the nation include significantly increased energy efficiency, reduced consumption of fossil fuels, pollutant and CO{sub 2} emissions from power generation, enhanced security from power interruptions as well as enhanced economic activity and job creation. An integrated micro-CHP energy system provides advantages over conventional power generation, since the energy is used more efficiently by means of efficient heat recovery. Foreign companies are readily selling

Benefits of CHP Partnership

Science.gov (United States)

Learn about the benefits of being a EPA CHP Partner, which include expert advice and answers to questions, CHP news, marketing resources, publicity and recognition, and being associated with EPA through a demonstrated commitment to CHP.

Small-scale biomass CHP using gasa turbines: a scoping study

International Nuclear Information System (INIS)

James, D.W.; Landen, R.

1996-01-01

Various options for small-scale (up to 250 KWe) Combined Heat and Power (CHP) plants evaluated in this scoping study. Plants using small gas turbines, and able to use biomass fuels when available are included. Three detailed case studies of small-scale biomass CHP plants are compared to match specific technical options with customer requirements. The commercial development of such biomass-fired CHP units, using gas turbines, is shown to be economically viable depending on fuel costs and the continuation of existing financial incentives. (UK)

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.

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.

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

Radioisotope Heater Unit-Based Stirling Power Convertor Development at NASA Glenn Research Center

Science.gov (United States)

Wilson, Scott D.; Geng, Steven M.; Penswick, Lawrence; Schmitz, Paul C.

2017-01-01

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 variety of mission concepts have been studied by NASA and the U. S. Department of Energy that would utilize RPS for landers, probes, and rovers and only require milliwatts to tens of watts of power. These missions would contain science measuring instruments that could be distributed across planetary surfaces or near objects of interest in space solar flux insufficient for using solar cells. A low power Stirling convertor is being developed to provide an RPS option for future low power applications. Initial concepts convert heat available from several Radioisotope Heater Units to electrical power for spacecraft instruments and communication. Initial development activity includes defining and evaluating a variety of Stirling configurations and selecting one for detailed design, research of advanced manufacturing methods that could simplify fabrication, evaluating thermal interfaces, characterizing components and subassemblies to validate design codes, and preparing for an upcoming demonstration of proof of concept in a laboratory environment.

Optimal stochastic scheduling of CHP-PEMFC, WT, PV units and hydrogen storage in reconfigurable micro grids considering reliability enhancement

International Nuclear Information System (INIS)

Bornapour, Mosayeb; Hooshmand, Rahmat-Allah; Khodabakhshian, Amin; Parastegari, Moein

2017-01-01

Highlights: • Stochastic model is proposed for coordinated scheduling of renewable energy sources. • The effect of combined heat and power is considered. • Uncertainties of wind speed, solar radiation and electricity market price are considered. • Profit maximization, emission and AENS minimization are considered as objective functions. • Modified firefly algorithm is employed to solve the problem. - Abstract: Nowadays the operation of renewable energy sources and combined heat and power (CHP) units is increased in micro grids; therefore, to reach optimal performance, optimal scheduling of these units is required. In this regard, in this paper a micro grid consisting of proton exchange membrane fuel cell-combined heat and power (PEMFC-CHP), wind turbines (WT) and photovoltaic (PV) units, is modeled to determine the optimal scheduling state of these units by considering uncertain behavior of renewable energy resources. For this purpose, a scenario-based method is used for modeling the uncertainties of electrical market price, the wind speed, and solar irradiance. It should be noted that the hydrogen storage strategy is also applied in this study for PEMFC-CHP units. Market profit, total emission production, and average energy not supplied (AENS) are the objective functions considered in this paper simultaneously. Consideration of the above-mentioned objective functions converts the proposed problem to a mixed integer nonlinear programming. To solve this problem, a multi-objective firefly algorithm is used. The uncertainties of parameters convert the mixed integer nonlinear programming problem to a stochastic mixed integer nonlinear programming problem. Moreover, optimal coordinated scheduling of renewable energy resources and thermal units in micro-grids improve the value of the objective functions. Simulation results obtained from a modified 33-bus distributed network as a micro grid illustrates the effectiveness of the proposed method.

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

Science.gov (United States)

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

2009-01-01

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

Modeling work of a small scale gasifier/SOFC CHP system

Energy Technology Data Exchange (ETDEWEB)

Liu, M.; Aravind, P.V.; Qu, Z.; Woudstra, N.; Verkooijen, A.H.M. [Delft University of Technology (Netherlands). Dept. of Mechanical Engineering], Emails: ming.liu@tudelft.nl, p.v.aravind@tudelft.nl, z.qu@tudelft.nl, n.woudstra@tudelft.nl, a. h. m. verkooijen@tudelft.nl; Cobas, V.R.M. [Federal University of Itajuba (UNIFEI), Pinheirinhos, MG (Brazil). Dept. of Mechanical Engineering], E-mail: vlad@unifei.edu.br

2009-07-01

For a highly efficient biomass gasification/Solid Oxide Fuel Cell (SOFC) Combined Heat and Power (CHP) generation system, the gasifier, the accompanying gas cleaning technologies and the CHP unit must be carefully designed as an integrated unit. This paper describes such a system involving a two-stage fixed-bed down draft gasifier, a SOFC CHP unit and a gas cleaning system. A gas cleaning system with both low temperature and high temperature sections is proposed for coupling the gasifier and the SOFC. Thermodynamic modeling was carried out for the gasifier/SOFC system with the proposed gas cleaning system. The net AC electrical efficiency of this system is around 30% and the overall system efficiency is around 60%. This paper also describes various exergy losses in the system and the future plans for integrated gasifier-GCU-SOFC experiments from which the results will be used to validate the modeling results of this system. (author)

A study on electricity export capability of the μCHP system with spot price

DEFF Research Database (Denmark)

You, Shi; Træholt, Chresten; Poulsen, Bjarne

2009-01-01

of the muCHP unit, which influence the export capability of muCHP system, is firstly carried out in the intraday case study, followed by the annual case study which explores the annual system performance. The results show that the electricity export capability of a muCHP system is closely related to its...

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

Science.gov (United States)

Oriti, Salvatore M.

2015-01-01

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

Future market relevance of CHP installations with electrical ratings from 1 to 1000 kW

International Nuclear Information System (INIS)

Eicher, H.; Rigassi, R.

2003-12-01

This report for the Swiss Federal Office of Energy (SFOE) discusses the future market relevance of combined heat and power (CHP) installations with electrical ratings from 1 to 1000 kW. Developments over the past ten years are reviewed. Important reductions in the price of motor-driven CHP units and the price of the electrical power produced are noted and commented on. The technical market potential of CHP units and the degree to which this potential has been implemented are commented on. Work done, including CHP implementation in the industrial, commercial and residential areas, is commented on. Future developments both in the technical area as well as in commercial areas are commented on. Micro-gas-turbine based CHP systems are also discussed, as are fuel-cell based systems in both the higher and lower capacity power generation area. The prospects for CHP systems in general in the electricity generation area are discussed

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.

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.

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.

Management of fluctuations in wind power and CHP comparing two possible Danish strategies

International Nuclear Information System (INIS)

Lund, H.; Clark, W.W.

2002-01-01

Both CHP (combined heat and power production) and wind power are important elements of Danish energy policy. Today, approximately 50% of both the Danish electricity and heat demand are produced in CHP and more than 15% of the electricity demand is produced by wind turbines. Both technologies are essential for the implementation of Danish climate change response objectives, and both technologies are intended for further expansion in the coming decade. Meanwhile, the integration of CHP and wind power is subject to fluctuations in electricity production. Wind turbines depend on the wind, and CHP depends on the heat demand. This article discusses and analyses two different national strategies for solving this problem. One strategy, which is the current official government policy known as the export strategy, proposes to take advantage of the Nordic and European markets for selling and buying electricity. In this case, surplus electricity from wind power and CHP simply will be sold to neighbouring countries. Another strategy, the self-supply strategy, runs the CHP units to meet both demand and the fluctuations in the wind scheduling. In this case, investments in heat storages are necessary and heat pumps have to be added to the CHP units. Based on official Danish energy policy and energy plans, this article quantifies the problem for the year 2015 in terms of the amount of surplus electricity, and investments in heat pumps, etc. needed to solve the problem are calculated. Based on these results between the two different strategies, the conclusion is that the self-supply strategy is recommended over the official export strategy. (author)

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

Modelling and control synthesis of a micro-combined heat and power interface for a concentrating solar power system in off-grid rural power applications

Science.gov (United States)

Prinsloo, Gerro; Dobson, Robert; Brent, Alan; Mammoli, Andrea

2016-05-01

Concentrating solar power co-generation systems have been identified as potential stand-alone solar energy supply solutions in remote rural energy applications. This study describes the modelling and synthesis of a combined heat and power Stirling CSP system in order to evaluate its potential performance in small off-grid rural village applications in Africa. This Stirling micro-Combined Heat and Power (micro-CHP) system has a 1 kW electric capacity, with 3 kW of thermal generation capacity which is produced as waste heat recovered from the solar power generation process. As part of the development of an intelligent microgrid control and distribution solution, the Trinum micro-CHP system and other co-generation systems are systematically being modelled on the TRNSYS simulation platform. This paper describes the modelling and simulation of the Trinum micro-CHP configuration on TRNSYS as part of the process to develop the control automation solution for the smart rural microgrid in which the Trinum will serve as a solar powerpack. The results present simulated performance outputs for the Trinum micro-CHP system for a number of remote rural locations in Africa computed from real-time TRNSYS solar irradiation and weather data (yearly, monthly, daily) for the relevant locations. The focus of this paper is on the parametric modelling of the Trinum Stirling micro-CHP system, with specific reference to this system as a TRNSYS functional block in the microgrid simulation. The model is used to forecast the solar energy harvesting potential of the Trinum micro-CHP unit at a number of remote rural sites in Africa.

CFD Analysis of the Oscillating Flow within a Stirling Engine with an Additively Manufactured Foil Type Regenerator

Science.gov (United States)

Qiu, Songgang; Solomon, Laura

2017-11-01

The simplistic design, fuel independence, and robustness of Stirling convertors makes them the ideal choice for use in solar power and combined heat and power (CHP) applications. A lack of moving parts and the use of novel flexure bearings allows free-piston type Stirling engines to run in excess of ten years without degradation or maintenance. The key component to their overall efficiency is the regenerator. While a foil type regenerator outperforms a sintered random fiber regenerator, limitation in manufacturing and keeping uniform spacing between the foils has limited their overall use. However, with the advent of additive manufacturing, a robust foil type regenerator can be cheaply manufactured without traditional limitations. Currently, a CFD analysis of the oscillating internal flow within the novel design was conducted to evaluate the flow loses within the system. Particularly the pressure drop across the regenerator in comparison to a traditionally used random fiber regenerator. Additionally, the heat transfer and flow over the tubular heater hear was evaluated. The results of the investigation will be used to optimize the operation of the next generation of additively manufactured Stirling convertors. This research was supported by ARPA-E and West Virginia University.

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.

A Stochastic Unit Commitment Model for a Local CHP Plant

DEFF Research Database (Denmark)

Ravn, Hans V.; Riisom, Jannik; Schaumburg-Müller, Camilla

2005-01-01

Local CHP development in Denmark has during the 90’s been characterised by large growth primarily due to government subsidies in the form of feed-in tariffs. In line with the liberalisation process in the EU, Danish local CHPs of a certain size must operate on market terms from 2005. This paper...

Stochastic PSO-based heat and power dispatch under environmental constraints incorporating CHP and wind power units

Energy Technology Data Exchange (ETDEWEB)

Piperagkas, G.S.; Anastasiadis, A.G.; Hatziargyriou, N.D. [National Technical University of Athens, School of Electrical and Computer Engineering, Electric Power Division, 9, Iroon Polytechneiou Str., GR-15773 Zografou, Athens (Greece)

2011-01-15

In this paper an extended stochastic multi-objective model for economic dispatch (ED) is proposed, that incorporates in the optimization process heat and power from CHP units and expected wind power. Stochastic restrictions for the CO{sub 2}, SO{sub 2} and NO{sub x} emissions are used as inequality constraints. The ED problem is solved using a multi-objective particle swarm optimization technique. The available wind power is estimated from a transformation of the wind speed considered as a random variable to wind power. Simulations are performed on the modified IEEE 30 bus network with 2 cogeneration units and actual wind data. Results concerning minimum cost and emissions reduction options are finally drawn. (author)

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.

Hydrocarbon emissions from gas engine CHP-units. 2011 measurement program

Energy Technology Data Exchange (ETDEWEB)

Van Dijk, G.H.J. [KEMA, Arnhem (Netherlands)

2012-06-15

In December 2009, the Ministry of Infrastructure and Environment (IandM) issued the Decree on Emission Limits for Middle Sized Combustion Installations (BEMS). This decree imposes a first-time emission limit value (ELV) of 1500 mg C/m{sup 3}{sub o} at 3% O{sub 2} for hydrocarbons emitted by gas engines. IandM used the findings of two hydrocarbon emission measurement programs, executed in 2007 and 2009, as a guideline for this initial ELV. The programs did reveal substantial variation in the hydrocarbon emissions of the gas engines tested. This variation, and especially the uncertainty as to the role of engine and/or other parameters causing such variation, was felt to hamper further policy development. IandM therefore commissioned KEMA to perform follow-up measurements on ten gas engine CHP-units in 2011. Aim of this 2011 program is to assess hydrocarbon emission variation in relation to engine parameters and process conditions including maintenance status, and to atmospheric conditions. The 2011 program comprised two identical measurement sessions, one in spring and one in winter.

Review of CHP projections tp 2010

Energy Technology Data Exchange (ETDEWEB)

Choudhury, W.

2003-07-01

This report summarises the findings of a study examining market conditions for combined heat and power since 2000 and assessing the commercial position of cogeneration (CHP) in order to provide advice on likely distributed generation in relation to technology, location and commissioning timetables. Details are given of the modelling of the development of 'good quality' CHP by Cambridge Econometrics (CE), and the work carried out by ILEX updating the CE study. Modelling assumptions, market conditions for CHP since the CE study, the effect of market conditions on CE modelling assumptions, justified changes in assumptions, and evaluation of likely CHP capacity to 2010 are discussed.

CHP in Switzerland from 1990 to 1998. Thermal power generation including combined heat and power

International Nuclear Information System (INIS)

Kaufmann, U.

1999-01-01

The results of a study on thermal power generation in Switzerland show that combined heat and power (CHP) systems have grown rapidly. Statistics are presented on the development of CHP-based power and also on thermal power stations without waste heat usage. Figures are given for gas and steam turbine installations, combined gas and steam turbine stations and motor-driven CHP units. Power production is categorised, separating small and large (over 1 Megawatt electrical) power generation facilities. On-site, distributed power generation at consumers' premises and the geographical distribution of plant is described

Network Capacity Assessment of CHP-based Distributed Generation on Urban Energy Distribution Networks

Science.gov (United States)

Zhang, Xianjun

The combined heat and power (CHP)-based distributed generation (DG) or dis-tributed energy resources (DERs) are mature options available in the present energy market, considered to be an effective solution to promote energy efficiency. In the urban environment, the electricity, water and natural gas distribution networks are becoming increasingly interconnected with the growing penetration of the CHP-based DG. Subsequently, this emerging interdependence leads to new topics meriting serious consideration: how much of the CHP-based DG can be accommodated and where to locate these DERs, and given preexisting constraints, how to quantify the mutual impacts on operation performances between these urban energy distribution networks and the CHP-based DG. The early research work was conducted to investigate the feasibility and design methods for one residential microgrid system based on existing electricity, water and gas infrastructures of a residential community, mainly focusing on the economic planning. However, this proposed design method cannot determine the optimal DG sizing and siting for a larger test bed with the given information of energy infrastructures. In this context, a more systematic as well as generalized approach should be developed to solve these problems. In the later study, the model architecture that integrates urban electricity, water and gas distribution networks, and the CHP-based DG system was developed. The proposed approach addressed the challenge of identifying the optimal sizing and siting of the CHP-based DG on these urban energy networks and the mutual impacts on operation performances were also quantified. For this study, the overall objective is to maximize the electrical output and recovered thermal output of the CHP-based DG units. The electricity, gas, and water system models were developed individually and coupled by the developed CHP-based DG system model. The resultant integrated system model is used to constrain the DG's electrical

Deployment of FlexCHP System

Energy Technology Data Exchange (ETDEWEB)

Cygan, David [Gas Technology Inst., Des Plaines, IL (United States)

2015-11-01

The Gas Technology Institute (GTI), along with its partner Integrated CHP Systems Corporation, has developed and demonstrated an Ultra-Low-Nitrogen Oxide (ULN) Flexible Combined Heat and Power (FlexCHP) system that packages a state-of-the-art Capstone C65 gas microturbine and Johnston PFXX100 boiler with an innovative natural gas-fired supplemental burner. Supplemental burners add heat as needed in response to facility demand, which increases energy efficiency, but typically raises exhaust NOx levels, degrading local air quality unless a costly and complicated catalytic treatment system is added. The FlexCHP system increases energy efficiency and achieves the 2007 California Air Resource Board (CARB) distributed generation emissions standards for Nitrogen oxides (NOx), Carbon Monoxide (CO), and Total Hydrocarbons (THC) without catalytic exhaust gas treatment. The key to this breakthrough performance is a simple and reliable burner design which utilizes staged combustion with engineered internal recirculation. This ULN burner system successfully uses turbine exhaust as an oxidizer, while achieving high efficiencies and low emissions. In tests at its laboratory facilities in Des Plaines, Illinois, GTI validated the ability of the system to achieve emissions of NOx, CO, and THC below the CARB criteria of 0.07, 0.10, and 0.02 lb/MW-h respectively. The FlexCHP system was installed at the field demonstration site, Inland Empire Foods, in Riverside, California to verify performance of the technology in an applied environment. The resulting Combined Heat and Power (CHP) package promises to make CHP implementation more attractive, mitigate greenhouse gas emissions, and improve the reliability of electricity supply.

Islanded house operation using a micro CHP

NARCIS (Netherlands)

Molderink, Albert; Bakker, Vincent; Hurink, Johann L.; Smit, Gerardus Johannes Maria

2007-01-01

The µCHP is expected as the successor of the conventional high-efficiency boiler producing next to heat also electricity with a comparable overall efficiency. A µCHP appliance saves money and reduces greenhouse gas emission. An additional functionality of the µCHP is using the appliance as a

Stirling Engine Controller

Science.gov (United States)

Blaze, Gina M.

2004-01-01

and also safely shutdown the engines. The test will last for a period of 8000 to 9000 hours. Other types of tests that have been performed are: performance mapping, controller development, launch environment, and vibration emissions testing. Currently, the thermo-mechanical system branch is housing a RG-350, a stirling convertor. The convertor was used in previous tests such as a Hall Thruster test, world s first integrated test of a dynamic power system with electric propulsion. Another test performed was to conclude if free piston stirling convertors can be synchronized for vibration balancing, with no thermodynamic or electrical connections and not cause both to shutdown if one failed. The ability to reduce vibration by synchronizing convertor operation but still be able to operate when one partner fails is pertinent in space and terrestrial applications. The convertor is now being brought back into operation and a controller is in the process of being developed. This convertor will be used as a testbed for new controllers. I worked with Mary Ellen Roth on the electric engineering aspects of the RG-350. My main goal was to enhance the data collection process. I worked on different aspects of the RG-350, with a main focus on the engine controller. I drew a schematic of the wire connections in the engine controller, using PCB Express, so that a plan could be devised to connect the power meter properly between the output of the engine and the engine controller. I measured the power using two different instruments: Valhalla Scientific power meter and Ohio Semitronics power measurement device. The convertor is connected to an Agilent 34970A Data Acquisition/Switch Unit, which allows the user to measure, record, and monitor voltage, current, frequency, and temperature. I assisted in preparing the Data Acquisition for general operation. I also helped test a panel of transducers, which will be placed in the rack that powers and monitors the convertor.

Carbon emissions reduction potential in the US chemicals and pulp and paper industries by applying CHP technologies

International Nuclear Information System (INIS)

Khrushch, M.; Worrell, E.; Price, L.; Martin, N.; Einstein, D.

1999-01-01

The chemical and the pulp/paper industries combined provide 55% of CHP generation in the US industry. Yet, significant potential for new CHP capacities exists in both industries. From the present steam consumption data, the authors estimate about 50 GW of additional technical potential for CHP in both industries. The reduced carbon emissions will be equivalent to 44% of the present carbon emissions in these industries. They find that most of the carbon emissions reductions can be achieved at negative costs. Depending on the assumptions used in calculations, the economic potential of CHP in these industries can be significantly lower, and carbon emissions mitigation costs can be much higher. Using sensitivity analyses, they determine that the largest effect on the CHP estimate have the assumptions in the costs of CHP technology, in the assumed discount rates, in improvements in efficiency of CHP technologies, and in the CHP equipment depreciation periods. Changes in fuel and electricity prices and the growth in the industries' steam demand have less of an effect. They conclude that the lowest carbon mitigation costs are achieved with the CHP facility is operated by the utility and when industrial company that owns the CHP unit can sell extra electricity and steam to the open wholesale market. Based on the results of the analyses they discuss policy implications

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.

Analysis and optmization of CHP, CCHP, CHP-ORC, and CCHP-ORC systems

Science.gov (United States)

Hueffed, Anna Kathrine

Increased demand for energy, rising energy costs, and heightened environmental concerns are driving forces that continually press for the improvement and development of new technologies to promote energy savings and emissions reduction. Combined heating and power (CHP), combined cooling, heating, and power (CCHP), and organic Rankine cycles (ORC) are a few of the technologies that promise to reduce primary energy consumption (PEC), cost, and emissions. CHP systems generate electricity at or near the place of consumption using a prime mover, e.g. a combustion engine or a turbine, and utilize the accompanying exhaust heat that would otherwise be wasted to satisfy the building's thermal demand. In the case of CCHP systems, exhaust heat also goes to satisfy a cooling load. An organic Rankine cycle (ORC) combined with a CHP or CCHP system can generate electricity from any surplus low-grade heat, thereby reducing the total primary energy, cost, and emissions.

Grid Interaction of MV-connected CHP-plants during disturbances

NARCIS (Netherlands)

Coster, E.J.; Myrzik, J.M.A.; Kling, W.L.

2009-01-01

Nowadays the amount of distributed generation (DG) units is increasing rapidly. Most dominant are combined heat and power (CHP) plants and wind turbines. At this moment, in most systems, there are no requirements defined for short-circuit behavior of such generators connected to the medium voltage

Decentralised CHP in a competitive market

DEFF Research Database (Denmark)

Lund, Henrik

2004-01-01

The article agues that decentralised CHP plants is an important part of energy supply in Denmark.......The article agues that decentralised CHP plants is an important part of energy supply in Denmark....

Economic analysis of a supercritical coal-fired CHP plant integrated with an absorption carbon capture installation

International Nuclear Information System (INIS)

Bartela, Łukasz; Skorek-Osikowska, Anna; Kotowicz, Janusz

2014-01-01

Energy investments in Poland are currently focused on supercritical coal-fired unit technology. It is likely, that in the future, these units are to be integrated with carbon capture and storage (CCS) installations, which enable a significant reduction of greenhouse gas emissions into the atmosphere. A significant share of the energy market in Poland is constituted by coal-fired combined heat and power (CHP) plants. The integration of these units with CCS installation can be economically inefficient. However, the lack of such integration enhances the investment risk due to the possibility of appearing on the market in the near future high prices of emission allowances. The aforementioned factors and additional favorable conditions for the development of cogeneration can cause one to consider investing in large supercritical CHP plants. This paper presents the results of an economic analysis aimed at comparing three cases of CHP plants, one without an integrated CCS installation and two with such installations. The same steam cycle structure for all variants was adopted. The cases of integrated CHP plants differ from each other in the manner in which they recover heat. For the evaluation of the respective solutions, the break-even price of electricity and avoided emission cost were used. - Highlights: • The simulations of operation of CHP plants under changing load have been realized. • For analyzed cases sensitivity analyses of economic indices have been conducted. • Conditions of competitiveness for integration with CCS units have been identified. • Integration can be profitable if prices of allowance will reach high values, exceeding 50 €/MgCO 2 . • Others important factors are the investment costs and operation and maintenance costs

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.

Micro CHP: implications for energy companies

Energy Technology Data Exchange (ETDEWEB)

Harrison, Jeremy [EA Technology (United Kingdom); Kolin, Simon; Hestevik, Svein [Sigma Elektroteknisk A/S (Norway)

2000-08-01

This article explains how micro combined heat and power (CHP) technology may help UK energy businesses to maintain their customer base in the current climate of liberalisation and competition in the energy market The need for energy companies to adopt new technologies and adapt to changes in the current aggressive environment, the impact of privatisation, and the switching of energy suppliers by customers are discussed. Three potential routes to success for energy companies are identified, namely, price reductions, branding and affinity marketing, and added value services. Details are given of the implementation of schemes to encourage energy efficiency, the impact of the emissions targets set at Kyoto, the advantages of micro CHP generation, business opportunities for CHP, business threats from existing energy companies and others entering the field, and the commercial viability of micro CHP.

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.

Thermodynamic and economic optimization of a solar-powered Stirling engine for micro-cogeneration purposes

International Nuclear Information System (INIS)

Ferreira, Ana C.; Nunes, Manuel L.; Teixeira, José C.F.; Martins, Luís A.S.B.; Teixeira, Senhorinha F.C.F.

2016-01-01

Micro-cogeneration systems are a promising technology for improving the energy efficiency near the end user, allowing the optimal use of the primary energy sources and significant reductions in carbon emissions. Its use, still incipient, has a great potential for applications in the residential sector. This study aims to develop a methodology for the thermal-economic optimization of micro cogeneration units using Stirling engine as prime mover and concentrated solar energy as the heat source. The thermal-economic optimization was formulated considering the maximization of the annual worth from the system operation, subjected to the nonlinear thermodynamic and economic constraints. The physical model includes the limitations in the heat transfer processes and losses due to the pumping effects and the costing methodology was defined considering a purchase cost equation representative of each system component. Geometric and operational parameters were selected as decision variables. Numerical simulations were developed in MatLab"® programming language and the Generalized Pattern Search optimization algorithm with MADSPositiveBasis2N was used in the determination of the optimal solution. A positive annual worth for the defined input simulation conditions and the economic analysis disclosed a system, economically attractive, with a payback period of approximately 10 years. - Highlights: • Application of optimization methods to model a renewable powered Stirling engine. • The aim is to optimize design of each plant-component for the best economical outcome. • The objective function is the maximization of annual worth of micro-CHP system. • The optimal solution is sensitive to electricity feed-in-tariffs and fuel prices fluctuations. • The optimal solution is economically attractive, with a payback period of ≈10 years.

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

Combined Heat and Power (CHP) Partnership

Science.gov (United States)

The CHP Partnership seeks to reduce air pollution and water usage associated with electric power generation by promoting the use of CHP. The Partnership works to remove policy barriers and to facilitate the development of new projects.

Elimination of restraints on the propagation of combined heat and power (CHP) generation systems in Switzerland

International Nuclear Information System (INIS)

Rieder, S.; Landis, F.; Lienhard, A.; Marti Locher, F.; Krummenacher, S.

2009-04-01

This report for the Swiss Federal Office of Energy (SFOE) discusses the results of study initiated by the SFOE that was to investigate the reasons for the low level of proliferation of CHP technology in Switzerland. The two main questions asked - which factors inhibit the use of CHP in particular application areas and which energy-policy measures can remove such obstacles - are discussed. The use of CHP in various areas of application from waste incineration plants through to units used in residential buildings is analysed and commented on. Recommendations on measures that can be taken to enhance the use of CHP are discussed. Three strategy variants available to the public services area are presented and discussed. It is noted that a consensus between players in the technical and political areas is necessary

Small scale CHP: Alternative integration forms in the Danish energy system

International Nuclear Information System (INIS)

Boeg, Rasmus; Gatautis, Ramunas; Engberg Pedersen, Thomas; Schmidt, Rune; Ravn, Hans F.

2003-01-01

In Denmark, introduction of small scale combined heat and power (CHP) plants were part of the energy policy during the 1990's. Thus, the installed electricity capacity on this type of units multiplied approximately ten times during this decade, to constitute more than 2000 MW in 2000, or around 20% of total installed electricity capacity. The motivation for this development was mainly energy savings due to the relatively high thermal efficiency in combined production, and the associated reduction of emissions. The remuneration for the electricity delivered to the electrical network was in part based on a feed in tariff. The construction of the tariff reflected estimated benefits to the electrical system. With the liberalisation of the electricity markets this arrangement has been questioned, and it has been suggested that the differentiated payment to local CHP should be based on electricity market prising. For Denmark this would imply that the local CHP should trade the electricity on the Nordpool electricity spot market. This paper analyses parts of these two alternative ways of economic arrangements in relation to small scale CHP. First it describes the development and status till now. Then it analyses the production patterns and associated economic consequences of a change from the tariff based system to a market system. (BA)

Performance study of an innovative natural gas CHP system

International Nuclear Information System (INIS)

Fu, Lin; Zhao, Xiling; Zhang, Shigang; Li, Yan; Jiang, Yi; Li, Hui; Sun, Zuoliang

2011-01-01

In the last decade, technological innovation and changes in the economic and regulatory environment have resulted in increased attention to distributed energy systems (DES). Combined cooling heating and power (CHP) systems based on the gas-powered internal combustion engine (ICE) are increasingly used as small-scale distribution co-generators. This paper describes an innovative ICE-CHP system with an exhaust-gas-driven absorption heat pump (AHP) that has been set up at the energy-saving building in Beijing, China. The system is composed of an ICE, an exhaust-gas-driven AHP, and a flue gas condensation heat exchanger (CHE), which could recover both the sensible and latent heat of the flue gas. The steady performance and dynamic response of the innovative CHP system with different operation modes were tested. The results show that the system's energy utilization efficiency could reach above 90% based on lower heating value (LHV) of natural gas; that is, the innovative CHP system could increase the heat utilization efficiency 10% compared to conventional CHP systems, and the thermally activated components of the system have much more thermal inertia than the electricity generation component. The detailed test results provide important insight into CHP performance characteristics and could be valuable references for the control of CHP systems. The novel CHP system could take on a very important role in the CHP market. (author)

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.

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.

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.

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.

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.

330 kWe Packaged CHP System with Reduced Emissions

Energy Technology Data Exchange (ETDEWEB)

Plahn, Paul [Cummins Power Generation, Minneapolis, MN (United States); Keene, Kevin [Cummins Power Generation, Minneapolis, MN (United States); Pendray, John [Cummins Power Generation, Minneapolis, MN (United States)

2015-03-31

The objective of this project was to develop a flexible, 330 kWe packaged Combined Heat and Power (CHP) system that can be deployed to commercial and light industrial applications at a lower total cost of ownership than current CHP solutions. The project resulted in a CHP system that is easy to use and inexpensive to install, offering world class customer support, while providing a low-emissions, higher-efficiency internal combustion engine for a CHP system of this size.

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)

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.

Dicty_cDB: CHP827 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available CH (Link to library) CHP827 (Link to dictyBase) - - - Contig-U15898-1 - (Link to Or...iginal site) CHP827F 148 - - - - - - Show CHP827 Library CH (Link to library) Clone ID CHP827 (Link to dicty...Base) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U15898-1 Original site URL http://dictycdb.b...ments: (bits) Value N AC116984 |AC116984.2 Dictyostelium discoideum chromosome 2 map 2567470-3108875 strain ...18q21 clone:RP11-866E20, WORKING DRAFT SEQUENCE, 18 unordered pieces. 42 0.073 4 CK406764 |CK406764.1 AUF_IfLvr_212_c09 Ict

Toxin-antitoxin loci as stress-response-elements: ChpAK/MazF and ChpBK cleave translated RNAs and are counteracted by tmRNA

DEFF Research Database (Denmark)

Christensen, S.K.; Pedersen, K.; Hansen, Flemming G.

2003-01-01

Prokaryotic chromosomes encode toxin-antitoxin loci, often in multiple copies. In most cases, the function of these genes is not known. The chpA (mazEF) locus of Escherichia coli has been described as a cell killing module that induces bacterial apoptosis during nutritional stress. However, we...... found recently that ChpAK (MazF) does not confer cell killing but rather, induces a bacteriostatic condition from which the cells could be resuscitated. Results presented here yield a mechanistic explanation for the detrimental effect on cell growth exerted by ChpAK and the homologous ChpBK protein of E......AK cleaved tmRNA in its coding region. Thus, ChpAK and ChpBK inhibit translation by a mechanism very similar to that of E. coli RelE. On the basis of these results, we propose a model that integrates TA loci into general prokaryotic stress physiology....

Micro-CHP for self-supply in the housing industry. Profitability and system integration; Mikro-BHKW zur Eigenversorgung in der Wohnungswirtschaft. Wirtschaftlichkeit und Systemintegration

Energy Technology Data Exchange (ETDEWEB)

Hollinger, Raphael; Buettner, Markus; Erge, Thomas; Wille-Haussmann, Bernhard; Wittwer, Christof [Fraunhofer-Institut fuer Solare Energiesysteme ISE, Freiburg (Germany)

2011-07-01

The use of micro-CHP units in multifamily buildings is particularly profitable if the produced electricity - coupled with the thermal energy production - is used directly by the operator or sold locally. To maximize the share of own consumption the use of thermal storages to operate the CHP at times of high electrical demand is necessary. By conducting a field test it is shown that the share of own consumption can be increased by predictive control of CHP with thermal storages. The approach increases the profitability of the CHP operation under today's conditions as well as the system integration of the CHP electricity. (orig.)

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.)

CHP Partnership Partners

Science.gov (United States)

Partners of EPA's Combined Heat and Power Partnership include federal, state, and local government agencies and private organizations such as energy users, energy service companies, CHP project developers and consultants, and equipment manufacturers.

Combined Heat and Power (CHP) as a Compliance Option under the Clean Power Plan: A Template and Policy Options for State Regulators

Energy Technology Data Exchange (ETDEWEB)

None

2015-07-30

Combined Heat and Power (CHP) is an important option for states to consider in developing strategies to meet their emission targets under the US Environmental Protection Agency's Clean Power Plan. This Template is designed to highlight key issues that states should consider when evaluating whether CHP could be a meaningful component of their compliance plans. It demonstrates that CHP can be a valuable approach for reducing emissions and helping states achieve their targets. While the report does not endorse any particular approach for any state, and actual plans will vary dependent upon state-specific factors and determinations, it provides tools and resources that states can use to begin the process, and underscores the opportunity CHP represents for many states. . By producing both heat and electricity from a single fuel source, CHP offers significant energy savings and carbon emissions benefits over the separate generation of heat and power, with a typical unit producing electricity with half the emissions of conventional generation. These efficiency gains translate to economic savings and enhanced competitiveness for CHP hosts, and emissions reductions for the state, along with helping to lower electric bills; and creating jobs in the design, construction, installation and maintenance of equipment. In 2015, CHP represents 8 percent of electric capacity in the United States and provides 12 percent of total power generation. Projects already exist in all 50 states, but significant technical and economic potential remains. CHP offers a tested way for states to achieve their emission limits while advancing a host of ancillary benefits.

Techno, Economic and Environmental Assessment of a Combined Heat and Power (CHP System—A Case Study for a University Campus

Directory of Open Access Journals (Sweden)

Khuram Pervez Amber

2018-05-01

Full Text Available Universities in the United Kingdom that have installed Combined Heat and Power (CHP technology are making good moves towards achieving their CO2 reduction targets. However, CHP may not always be an economical option for a university campus due to numerous factors. Identification of such factors is highly important before making an investment decision. A detailed technical, economic, and environmental feasibility of CHP is, therefore, indispensable. This study aims to undertake a detailed assessment of CHP for a typical university campus and attempts to highlight the significance of such factors. Necessary data and information were collected through site visits, whereas the CHP sizing was performed using the London South Bank University (LSBU CHP model. The results suggest that there is a strong opportunity of installing a 230 kW CHP that will offset grid electricity and boilers thermal supply by 47% and 75%, respectively, and will generate financial and environmental yearly savings of £51k and 395 t/CO2, respectively. A wider spark gap decreases the payback period of the project and vice versa. The capital cost of the project could affect the project’s economics due to factors, such as unavailability of space for CHP, complex existing infrastructure, and unavailability of a gas connection.

Future market relevance of CHP installations with electrical ratings from 1 to 1000 kW; Zukuenftige Marktbedeutung von WKK-Anlagen mit 1 - 1000 kW elektrischer Leistung

Energy Technology Data Exchange (ETDEWEB)

Eicher, H.; Rigassi, R.

2003-12-15

This report for the Swiss Federal Office of Energy (SFOE) discusses the future market relevance of combined heat and power (CHP) installations with electrical ratings from 1 to 1000 kW. Developments over the past ten years are reviewed. Important reductions in the price of motor-driven CHP units and the price of the electrical power produced are noted and commented on. The technical market potential of CHP units and the degree to which this potential has been implemented are commented on. Work done, including CHP implementation in the industrial, commercial and residential areas, is commented on. Future developments both in the technical area as well as in commercial areas are commented on. Micro-gas-turbine based CHP systems are also discussed, as are fuel-cell based systems in both the higher and lower capacity power generation area. The prospects for CHP systems in general in the electricity generation area are discussed

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.

Research on the Improvement of a Natural Gas Fired Burner for the CHP Application in a Central Heating Boiler using Radiant Burner Technology

Energy Technology Data Exchange (ETDEWEB)

Bieleveld, T.

2010-08-15

These days, the reduction of CO2 emissions from combustion devices is one of the main priorities for each design improvement. For the domestic use of the central heating boiler, Microgen Engine Corporation produces free piston Stirling engines for the Combined Heat and Power (CHP) application in these central heating boilers (Dutch: 'HRe ketel'). With CHP, the generation of electricity and heat are combined to increase overall efficiency, as heat is generally a waste product from the combustion to electric generation process. In this application, the Stirling engine, which can be defined as an external combustion engine, is heated by a natural gas fired engine-burner and cooled by a coolant flow. The heat transfer into the engine is converted into mechanical work and a heat flux from the engine. The mechanical work is used to produce electricity via a linear alternator. Heat in the flue gasses from the engine-burner is reused in a secondary burner and condensing heat exchanger. The coolant flow from the engine, after passing the secondary burner, is used for heating purposes. The heat transfer from engine-burner to the Stirling engine is analyzed and via several motivations it is found that it is favorable to improve fuel to electric conversion efficiency, for which the heat transfer efficiency of the engine-burner to the Stirling engine should be improved, as the engine design is not to be altered. From an initially developed linear free piston Stirling engine model and measurements performed at Microgen Engine Corporation, St. Petersborough, (UK), the engine power demand and engine-burner performance are found. The results are used to visualize the current energy flows of the Stirling engine and engine burner subsystem. The heat transfer to the engine is analyzed to find possible heat transfer improvements. It is concluded that heat transfer from the engine-burner to the engine can be approved if the flue losses due to convective heat transfer are

Increased power to heat ratio of small scale CHP plants using biomass fuels and natural gas

International Nuclear Information System (INIS)

Savola, Tuula; Fogelholm, Carl-Johan

2006-01-01

In this paper, we present a systematic study of process changes for increased power production in 1-20 MW e combined heat and power (CHP) plants. The changes are simulated, and their economic feasibility evaluated by using existing small scale CHP case plants. Increasing power production in decentralised CHP plants that operate according to a certain heat demand could reduce the fuel consumption and CO 2 emissions per power unit produced and improve the feasibility of CHP plant investments. The CHP plant process changes were simulated under design and off design conditions and an analysis of power and heat production, investment costs and CO 2 emissions was performed over the whole annual heat demand. The results show that using biomass fuels, there are profitable possibilities to increase the current power to heat ratios, 0.23-0.48, of the small scale CHP plants up to 0.26-0.56, depending on the size of the plant. The profitable changes were a two stage district heat exchanger and the addition of a steam reheater and a feed water preheater. If natural gas is used as an additional fuel, the power to heat ratio may be increased up to 0.35-0.65 by integrating a gas engine into the process. If the CO 2 savings from the changes are also taken into account, the economic feasibility of the changes increases. The results of this work offer useful performance simulation and investment cost knowledge for the development of more efficient and economically feasible small scale CHP processes

Integration of fuel cells into residential buildings

International Nuclear Information System (INIS)

Bell, J.M.; Entchev, E.; Gusdorf, J.; Szadkowski, F.; Swinton, M.; Kalbfleisch, W.; Marchand, R.

2004-01-01

Integration of small combined heat and power systems (CHP) into residential buildings is challenging as the loads are small, the load diversity is limited and there are a number of unresolved issues concerning sizing, control, peak loads, emergency operation, grid connection and export, etc. Natural Resources Canada has undertaken an initiative to investigate and develop techniques for the integration of small CHP systems into residential buildings using a highly instrumented house modified to allow quick installation and thorough monitoring of CHP integration techniques as well determining the performance of the CHP systems themselves when operating in a house. The first CHP system installed was a Stirling engine residential CHP system. It was used to examine the completeness of the CHP modifications to the house, to evaluate various building integration techniques and to measure the performance of the CHP system itself. The testing demonstrated the modified house to be an excellent facility for the development of CHP building integration techniques and the testing of residential CHP systems. The Stirling engine CHP system was found to operate well and produce meaningful input to the house. A second system (residential fuel cell) is presently being installed and building integration techniques and the performance of the fuel cell will be tested over the coming year. (author)

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

Crystallization and preliminary crystallographic analysis of the human calcineurin homologous protein CHP2 bound to the cytoplasmic region of the Na+/H+ exchanger NHE1

International Nuclear Information System (INIS)

Ben Ammar, Youssef; Takeda, Soichi; Sugawara, Mitsuaki; Miyano, Masashi; Mori, Hidezo; Wakabayashi, Shigeo

2005-01-01

Crystallization of the human CHP2–NHE1 binding domain complex. Calcineurin homologous protein (CHP) is a Ca 2+ -binding protein that directly interacts with and regulates the activity of all plasma-membrane Na + /H + -exchanger (NHE) family members. In contrast to the ubiquitous isoform CHP1, CHP2 is highly expressed in cancer cells. To understand the regulatory mechanism of NHE1 by CHP2, the complex CHP2–NHE1 (amino acids 503–545) has been crystallized by the sitting-drop vapour-diffusion method using PEG 3350 as precipitant. The crystals diffract to 2.7 Å and belong to a tetragonal space group, with unit-cell parameters a = b = 49.96, c = 103.20 Å

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.

The design of Chp plants

International Nuclear Information System (INIS)

Tomassetti, G.

2001-01-01

Chp is considered with a bottom-up view, as the most efficient way to satisfy the needs of the users. In order to achieve optimal results a particular care must be used in analyzing the thermal and electrical loads and their interactions. On this basis and taking into account the relationships among the user and the suppliers of electricity, fuels and heat, the energy market structure, the cost of energy and the tax assessment it is possible to properly design Chp plants with benefits for the users [it

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.

The capacity credit of micro-combined heat and power

International Nuclear Information System (INIS)

Hawkes, A.D.; Leach, M.A.

2008-01-01

This article is concerned with development of a methodology to determine the capacity credit of micro-combined heat and power (micro-CHP), and application of the method for the UK. Capacity credit is an important parameter in electricity system planning because it measures the amount of conventional generation that would be displaced by an alternative technology. Firstly, a mathematical formulation is presented. Capacity credit is then calculated for three types of micro-CHP units-Stirling engine, internal combustion engine, and fuel cell systems-operating under various control strategies. It is found that low heat-to-power ratio fuel cell technologies achieve the highest capacity credit of approximately 85% for a 1.1 GW penetration when a heat-led control strategy is applied. Higher heat-to-power ratio Stirling engine technology achieves approximately 33% capacity credit for heat-led operation. Low heat-to-power ratio technologies achieve higher capacity credit because they are able to continue operating even when heat demand is relatively low. Capacity credit diminishes as penetration of the technology increases. Overall, the high capacity credit of micro-CHP contributes to the viewpoint that the technology can help meet a number of economic and environmental energy policy aims

Contribution of wind power and CHP to exports from Western Denmark during 2000-2004

International Nuclear Information System (INIS)

Mignard, D.; Harrison, G.P.; Pritchard, C.L.

2007-01-01

The experience of Denmark is used by the United Kingdom's anti-wind lobby to demonstrate that intermittency and inaccuracies in wind forecasting make wind power ineffective and expensive. A further assertion is that most of the power is 'unwanted' since up to 80% of it is exported. Here, available data for Danish energy production for 2000-2004 is used to assess the link between wind generation and exports and test the validity of these claims. Net exports in Western Denmark showed good correlation with wind production. However, they were more significantly correlated with the production from local combined heat and power (CHP) plants. In order to test the 80% export claim, a simple technique was devised to correlate and rank hourly net exports and generation from wind and local CHP. In the case where net exports were primarily attributed to (or blamed on) wind, 44-84% of annual wind production was deemed to be exported, with wind 'causing' 57-79% of net annual exports. For this extreme scenario, the percentage values are in line with those of critics. However, under the opposite extreme scenario in which exports are attributed to local CHP, 77-94% of exports were caused by CHP and only 4-32% of wind production was exported. Overall, this study shows that there is some degree of correlation between net exports and wind power, but that the claim that 80% is exported is unwarranted since it ignores the demonstrably stronger influence of local CHP. (author)

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...

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

Science.gov (United States)

Lewandowski, Edward J.

2013-01-01

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

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

Decentralised energy supply as our future energy supply system? - An interview with Prof. Alexander Wokaun

International Nuclear Information System (INIS)

Nagel, Ch.

2002-01-01

In this interview with Professor Alexander Wokaun, head of General Energy Research at the Paul Scherrer Institute (PSI) in Villigen, Switzerland, the decentralised use of small, gas-fired combined heat and power (CHP) units is discussed as a means of meeting Switzerland's Kyoto CO 2 commitments. The question on which of several new CHP technologies such as gas-fired engines and turbines, Stirling engines, fuel cells and thermo-photovoltaics will win the race is discussed. The efficiency and application areas of CHP technologies are examined and the problems involved when controlling complex electricity grids with many small decentrally placed generating facilities is discussed. Finally, Professor Wokaun is asked for his opinion on what the Swiss power mix will look like in 20 years

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.

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.

Computer experimental analysis of the CHP performance of a 100 kW e SOFC Field Unit by a factorial design

Science.gov (United States)

Calì, M.; Santarelli, M. G. L.; Leone, P.

Gas Turbine Technologies (GTT) and Politecnico di Torino, both located in Torino (Italy), have been involved in the design and installation of a SOFC laboratory in order to analyse the operation, in cogenerative configuration, of the CHP 100 kW e SOFC Field Unit, built by Siemens-Westinghouse Power Corporation (SWPC), which is at present (May 2005) starting its operation and which will supply electric and thermal power to the GTT factory. In order to take the better advantage from the analysis of the on-site operation, and especially to correctly design the scheduled experimental tests on the system, we developed a mathematical model and run a simulated experimental campaign, applying a rigorous statistical approach to the analysis of the results. The aim of this work is the computer experimental analysis, through a statistical methodology (2 k factorial experiments), of the CHP 100 performance. First, the mathematical model has been calibrated with the results acquired during the first CHP100 demonstration at EDB/ELSAM in Westerwoort. After, the simulated tests have been performed in the form of computer experimental session, and the measurement uncertainties have been simulated with perturbation imposed to the model independent variables. The statistical methodology used for the computer experimental analysis is the factorial design (Yates' Technique): using the ANOVA technique the effect of the main independent variables (air utilization factor U ox, fuel utilization factor U F, internal fuel and air preheating and anodic recycling flow rate) has been investigated in a rigorous manner. Analysis accounts for the effects of parameters on stack electric power, thermal recovered power, single cell voltage, cell operative temperature, consumed fuel flow and steam to carbon ratio. Each main effect and interaction effect of parameters is shown with particular attention on generated electric power and stack heat recovered.

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.

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

Development and experimental testing of a hybrid Stirling engine-adsorption chiller auxiliary power unit for heavy trucks

International Nuclear Information System (INIS)

Flannery, Barry; Lattin, Robert; Finckh, Oliver; Berresheim, Harald; Monaghan, Rory F.D.

2017-01-01

Highlights: • Free-piston Stirling engine for truck APU. • Waste heat driven adsorption chiller for cab air conditioning. • Reduced-order model comparing proposed system to existing technology. • Experimental test data from prototype test rig. - Abstract: This paper identifies the key technical requirements for a heavy truck auxiliary power unit (APU) and explores a potential alternative technology for use in a next-generation APU which could eliminate key problems related to emissions, noise and maintenance experienced today by conventional diesel engine-vapour compression APUs. The potential performance of a novel hybrid Stirling engine-adsorption chiller concept is investigated and benchmarked against the incumbent technology using a reduced-order model based on experimental data. Experimental results from a Stirling-adsorption system (SAS) prototype test rig are also presented which highlight system integration dynamics and overall performance. The adsorption chiller achieved an average COP of 0.42 ± 0.06 and 2.3 ± 0.1 kW_t of cooling capacity at the baseline test condition. The prototype SAS test rig demonstrates that there appear to be no major technology barriers remaining that would prevent adoption of the SAS concept in a next-generation APU. Such a system could offer a reduction of exhaust emissions, greenhouse gases (GHG), ozone-depleting substances, noise, low maintenance and the potential for fuel flexibility and higher reliability. Preliminary modelling results indicate that the proposed system could offer superior overall electrical and cooling efficiencies compared to incumbent APUs and demonstrate a payback period of 4.6 years.

Crystallization and preliminary crystallographic analysis of the human calcineurin homologous protein CHP2 bound to the cytoplasmic region of the Na{sup +}/H{sup +} exchanger NHE1

Energy Technology Data Exchange (ETDEWEB)

Ben Ammar, Youssef [Department of Molecular Physiology, National Cardiovascular Center Research Institute, Fujishiro-dai 5-7-1, Suita, Osaka 565-8565 (Japan); Takeda, Soichi [Department of Cardiac Physiology, National Cardiovascular Center Research Institute, Fujishiro-dai 5-7-1, Suita, Osaka 565-8565 (Japan); Sugawara, Mitsuaki; Miyano, Masashi [Structural Biophysics Laboratory, RIKEN Harima Institute at SPring-8, Kouto, Mikazuki, Sayo, Hyogo 679-5148 (Japan); Mori, Hidezo [Department of Cardiac Physiology, National Cardiovascular Center Research Institute, Fujishiro-dai 5-7-1, Suita, Osaka 565-8565 (Japan); Wakabayashi, Shigeo, E-mail: wak@ri.ncvc.go.jp [Department of Molecular Physiology, National Cardiovascular Center Research Institute, Fujishiro-dai 5-7-1, Suita, Osaka 565-8565 (Japan)

2005-10-01

Crystallization of the human CHP2–NHE1 binding domain complex. Calcineurin homologous protein (CHP) is a Ca{sup 2+}-binding protein that directly interacts with and regulates the activity of all plasma-membrane Na{sup +}/H{sup +}-exchanger (NHE) family members. In contrast to the ubiquitous isoform CHP1, CHP2 is highly expressed in cancer cells. To understand the regulatory mechanism of NHE1 by CHP2, the complex CHP2–NHE1 (amino acids 503–545) has been crystallized by the sitting-drop vapour-diffusion method using PEG 3350 as precipitant. The crystals diffract to 2.7 Å and belong to a tetragonal space group, with unit-cell parameters a = b = 49.96, c = 103.20 Å.

Stockholm CHP potential - An opportunity for CO2 reductions?

International Nuclear Information System (INIS)

Danestig, Maria; Gebremehdin, Alemayehu; Karlsson, Bjoern

2007-01-01

The potential for combined heat and power (CHP) generation in Stockholm is large and a total heat demand of about 10 TWh/year can be met in a renewed large district heating system. This model of the Stockholm district heating system shows that CHP generation can increase from 8% in 2004 to 15.5% of the total electricity generation in Sweden. Increased electricity costs in recent years have awakened an interest to invest in new electricity generation. Since renewable alternatives are favoured by green certificates, bio-fuelled CHP is most profitable at low electricity prices. Since heat demand in the district heating network sets the limit for possible electricity generation, a CHP alternative with a high electricity to heat ratio will be more profitable at when electricity prices are high. The efficient energy use in CHP has the potential to contribute to reductions in carbon dioxide emissions in Europe, when they are required and the European electricity market is working perfectly. The potential in Stockholm exceeds Sweden's undertakings under the Kyoto protocol and national reduction goals. (author)

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 ...

Experimental study on a project with CHP system basing on absorption cycles

International Nuclear Information System (INIS)

Sun, Jian; Fu, Lin; Sun, Fangtian; Zhang, Shigang

2014-01-01

A new heat recovery system for the CHP (combined heating and power) is presented, and HRU (heat recovery unit) and AHE (absorption heat exchanger) are invented to improve the total energy efficiency of the conventional CHP system by more than 20%, which are installed at the thermal power plant and the heating substation separately. The HRU could recover the low grade heat of exhausted steam from the turbine directly, and the AHE could decrease the temperature of back water of primary pipe to a lower temperature than that of secondary pipe without changing the flow rate of secondary pipe. A large demonstration project employing this technology has been built in Datong of China. And experimental results of HRU and AHE are presented to evaluate this system. - Highlights: • The total energy efficiency of CHP could by increased by more than 20%. • Temperature of back water of primary pipe could be lower than that of secondary pipe. • Heating capacity of primary pipe could be increased significantly. • Low grade heat of exhausted steam from turbine could be recovered directly

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.

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.

Evaluation of an alkaline fuel cell system as a micro-CHP

International Nuclear Information System (INIS)

Verhaert, Ivan; Mulder, Grietus; De Paepe, Michel

2016-01-01

Highlights: • Sensitivity analysis on system configuration of the AFC as a micro-CHP. • Flow rate in the secondary heating circuit can be used to control water management. • Part load behavior of fuel cells is compared to other micro-CHP technologies. • For future energy demand in buildings fuel cells have the best performance. - Abstract: Micro-cogeneration is an emerging technology to reduce the non-renewable energy demand in buildings and reduce peak load in the grid. Fuel cell based cogeneration (CHP) has interesting prospects for building applications, even at relatively low heat demand. This is due to their partial load behavior which is completely different, compared to other micro-CHP technologies. Within the fuel cell technologies suitable for small scale CHP or micro-CHP, the existing configuration of an alkaline fuel cell system is analyzed. This analysis is based on validated models and offers a control strategy to optimize both water management and energy performance of the alkaline fuel cell system. Finally, the model of the alkaline fuel cell system with optimized control strategy is used to compare its part load behavior to other micro-CHP technologies.

Modeling of non-linear CHP efficiency curves in distributed energy systems

DEFF Research Database (Denmark)

Milan, Christian; Stadler, Michael; Cardoso, Gonçalo

2015-01-01

Distributed energy resources gain an increased importance in commercial and industrial building design. Combined heat and power (CHP) units are considered as one of the key technologies for cost and emission reduction in buildings. In order to make optimal decisions on investment and operation...... for these technologies, detailed system models are needed. These models are often formulated as linear programming problems to keep computational costs and complexity in a reasonable range. However, CHP systems involve variations of the efficiency for large nameplate capacity ranges and in case of part load operation......, which can be even of non-linear nature. Since considering these characteristics would turn the models into non-linear problems, in most cases only constant efficiencies are assumed. This paper proposes possible solutions to address this issue. For a mixed integer linear programming problem two...

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

CHP expansion strategy in North Rhine-Westphalia. A blueprint for other regions

International Nuclear Information System (INIS)

Holzapfel, Dominik; Schneider, Sabine

2015-01-01

The North Rhine-Westphalian state government intends to increase the share of combined heat and power (CHP) generation to at least 25 % by 2020. Since 2013, the campaign ''CHP.NRW - Power Meets Heat'' (''KWK.NRW - Strom trifft Waerme'') of the EnergyAgency.NRW, is has been running on behalf of the NRW Climate Protection Ministry, to publicise this technology and to promote its expansion. The campaign accompanies the State Government's CHP Stimulus Programme. The EnergyAgency.NRW has organised companies and research institutions, associations and interest groups under the umbrella of ''CHP.NRW - Power Meets Heat'', aiming at co-ordinated and intensified activities in the field of combined heat and power generation. The target of the initial-project ''roadmap/CHP.NRW'' of the ''Virtual Institute / CHP.NRW'' is to develop a guideline for the application and optimisation of CHP-systems.

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.

CHP plant Legionowo Poland. Description of the electricity market in Poland/CHP-feasibility analysis

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-04-01

In 1997, a new energy law was passed in Poland. An important element of the law is that local energy is made obligatory. The law describes obligatory tasks and procedures for the Polish municipalities related to planning and organisation of the energy sector. With the objective of supporting the Polish municipalities in their obligations according to the energy law, the project 'Energy Planning in Poland at Municipal Level - Support to Decision Makers' was launched. As part of the project, Municipal Guideline Reports have been elaborated for three model municipalities. These guidelines present the basis for energy supply plans in the three municipalities. For the city of Legionowo, the following was recommended: 1. The planning processes initiated during the project should be continued/followed up, 2. Master Plan for the district heating system should be prepared, 3. The possibilities of establishment of a major natural gas-fired CHP plant of the combined cycle type should be investigated. The present report describes the electricity market in Poland, the market in which a CHP plant in Legionowo will have to operate. Furthermore the report presents the results of the feasibility analysis carried out for a new CHP plant in Legionowo. (BA)

Methodology for evaluation of industrial CHP production

International Nuclear Information System (INIS)

Pavlovic, Nenad V.; Studovic, Milovan

2000-01-01

At the end of the century industry switched from exclusive power consumer into power consumer-producer which is one of the players on the deregulated power market. Consequently, goals of industrial plant optimization have to be changed, making new challenges that industrial management has to be faced with. In the paper is reviewed own methodology for evaluation of industrial power production on deregulated power market. The methodology recognizes economic efficiency of industrial CHP facilities as a main criterion for evaluation. Energy and ecological efficiency are used as additional criteria, in which implicit could be found social goals. Also, methodology recognizes key and limit factors for CHP production in industry. It could be successful applied, by use of available commercial software for energy simulation in CHP plants and economic evaluation. (Authors)

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.

A Geothermal Energy Supported Gas-steam Cogeneration Unit as a Possible Replacement for the Old Part of a Municipal CHP Plant (TEKO

Directory of Open Access Journals (Sweden)

L. Böszörményi

2001-01-01

Full Text Available The need for more intensive utilization of local renewable energy sources is indisputable. Under the current economic circumstances their competitiveness in comparison with fossil fuels is rather low, if we do not take into account environmental considerations. Integrating geothermal sources into combined heat and power production in a municipal CHP plant would be an excellent solution to this problem. This concept could lead to an innovative type of power plant - a gas-steam cycle based, geothermal energy supported cogeneration unit.

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.

Biomass CHP Catalog of Technologies

Science.gov (United States)

This report reviews the technical and economic characterization of biomass resources, biomass preparation, energy conversion technologies, power production systems, and complete integrated CHP systems.

Evaluation of the impact of the liberalisation of the European electricity market on the CHP, District heating and cooling sector; 'Save CHP/DHC'. Final report

International Nuclear Information System (INIS)

2000-08-01

Improved energy efficiency will play a key role in meeting the EU Kyoto target economically. In addition to a significant positive environmental impact, improved energy efficiency will lead to a more sustainable energy policy and enhanced security of supply. The study: 1) Identifies and evaluates parameters and conditions which in relation to the liberalisation of the electricity market will have an impact on the CHP/DHC sector in EU15 and Poland. 2) Establishes an information base on CHP/DHC systems in EU15 and Poland. 3) Analyses the CHP/DHC sector and its ability to meet changing market conditions. 4) Assesses the effect of the liberalised electricity market on electricity production in relation to CHP/district heating and cooling. 5) Identifies threats for the viability of CHP/DHC in a liberalised market and evaluates means and measures to overcome such threats. The study brings forward the goals and commitments in respect of European energy and environmental policy and gives an overview of the present and expected future framework in which CHP/DHC is to operate. The study evaluates the viability of the sector at an overall level and for different groups/categories of CHP/DHC systems in different countries. The effects of existing or proposed national public measures are analysed. The analyses are essential to decision makers in the transition process towards a fully liberalised market. Recognised uncertainties in the market during the transition period may cause either a temporary or a permanent recession for the CHP/DHC sector. Improved understanding and recognition of threats and opportunities is important to all actors just now. The study can be considered a first step of a process to create a market situation, where the energy customers can make their choices under competition rules and where environmentally friendly and efficient CHP and DHC is considered an attractive business opportunity in competition with other energy supplies. (EHS)

Advanced Stirling Convertor Control Unit Testing at NASA Glenn Research Center in the Radioisotope Power Systems System Integration Laboratory

Science.gov (United States)

Dugala, Gina M.; Taylor, Linda M.; Kussmaul, Michael; Casciani, Michael; Brown, Gregory; Wiser, Joel

2017-01-01

Future NASA missions could include establishing Lunar or Martian base camps, exploring Jupiters moons and travelling beyond where generating power from sunlight may be limited. Radioisotope Power Systems (RPS) provide a dependable power source for missions where inadequate sunlight or operational requirements make other power systems impractical. Over the past decade, NASA Glenn Research Center (GRC) has been supporting the development of RPSs. The Advanced Stirling Radioisotope Generator (ASRG) utilized a pair of Advanced Stirling Convertors (ASC). While flight development of the ASRG has been cancelled, much of the technology and hardware continued development and testing to guide future activities. Specifically, a controller for the convertor(s) is an integral part of a Stirling-based RPS. For the ASRG design, the controller maintains stable operation of the convertors, regulates the alternating current produced by the linear alternator of the convertor, provides a specified direct current output voltage for the spacecraft, synchronizes the piston motion of the two convertors in order to minimize vibration as well as manage and maintain operation with a stable piston amplitude and hot end temperature. It not only provides power to the spacecraft but also must regulate convertor operation to avoid damage to internal components and maintain safe thermal conditions after fueling. Lockheed Martin Coherent Technologies has designed, developed and tested an Engineering Development Unit (EDU) Advanced Stirling Convertor Control Unit (ACU) to support this effort. GRC used the ACU EDU as part of its non-nuclear representation of a RPS which also consists of a pair of Dual Advanced Stirling Convertor Simulator (DASCS), and associated support equipment to perform a test in the Radioisotope Power Systems System Integration Laboratory (RSIL). The RSIL was designed and built to evaluate hardware utilizing RPS technology. The RSIL provides insight into the electrical

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.

Economic dispatch of a single micro-gas turbine under CHP operation

International Nuclear Information System (INIS)

Rist, Johannes F.; Dias, Miguel F.; Palman, Michael; Zelazo, Daniel; Cukurel, Beni

2017-01-01

Highlights: •Economic dispatch of a micro gas turbine is considered for smart grid integration. •A detailed thermodynamic cycle analysis is conducted for variable load CHP operation. •Benefits are shown for case studies with real demand profiles and energy tariffs. •Optimal unit schedule can be electricity, heat, revenue or maintenance-cost driven. -- Abstract: This work considers the economic dispatch of a single micro-gas turbine under combined heat and power (CHP) operation. A detailed thermodynamic cycle analysis is conducted on a representative micro-gas turbine unit with non-constant component efficiencies and recuperator bypass. Based on partial and full load configurations, an accurate optimization model is developed for solving the economic dispatch problem of integrating the turbine into the grid. The financial benefit and viability of this approach is then examined on four detailed scenarios using real data on energy demand profiles and electricity tariffs. The analysis considers the optimal operation in a large hotel, a full-service restaurant, a small hotel, and a residential neighborhood during various seasons. The optimal schedule follows four fundamental economic drivers which are electricity, heat, revenue, and maintenance-cost driven.

An assessment of the present and future opportunities for combined heat and power with district heating (CHP-DH) in the United Kingdom

International Nuclear Information System (INIS)

Kelly, Scott; Pollitt, Michael

2010-01-01

As global fuel reserves are depleted, alternative and more efficient forms of energy generation and delivery will be required. Combined heat and power with district heating (CHP-DH) provides an alternative energy production and delivery mechanism that is less resource intensive, more efficient and provides greater energy security than many popular alternatives. It will be shown that the economic viability of CHP-DH networks depends on several principles, namely (1) the optimisation of engineering and design principles; (2) organisational and regulatory frameworks; (3) financial and economic factors. It was found that in the long term DH is competitive with other energy supply and distribution technologies such as electricity and gas. However, in the short to medium term it is shown that economic risk, regulatory uncertainty and lock-in of existing technology are the most significant barriers to CHP-DH development. This research suggests that under the present regulatory and economic paradigm, the infrastructure required for DH networks remains financially prohibitive; the implementation of government policies are complicated and impose high transaction costs, while engineering solutions are frequently not implemented or economically optimised. If CHP-DH is going to play any part in meeting climate change targets then collaboration between public and private organisations will be required. It is clear from this analysis that strong local government involvement is therefore necessary for the co-ordination, leadership and infrastructural deployment of CHP-DH.

Multi-criteria evaluation for CHP system options

International Nuclear Information System (INIS)

Pilavachi, P.A.; Roumpeas, C.P.; Minett, S.; Afgan, N.H.

2006-01-01

Several Combined Heat and Power (CHP) system options have been considered for evaluation with respect to the end-user requirements. These included Internal Combustion Engines (Otto and Diesel), Gas Turbines, Steam Turbines and Combined Cycles covering a wide range of electrical output. Data have been obtained from literature and the CHP systems have been evaluated using different criteria such as overall efficiency, investment cost, fuel cost, electricity cost, heat cost, CO 2 production and footprint. A multi-criteria method is used with an agglomeration function based on the statistical evaluation of weight factors. The technical, economic and social aspects of each system have been evaluated in an integrated manner and the results have been compared by means of the Sustainability Index. Based on the above criteria and depending on the user requirements, the best CHP system options have been established

CHP systems to save money and cut carbon.

Science.gov (United States)

Hopkins, Ian

2014-10-01

According to Ian Hopkins, a director of ENER-G Combined Power--which has delivered more than 50 CHP-led energy services contracts within the healthcare sector, having, for the past 30 years, designed and manufactured CHP systems at its global headquarters and R&D centre in Salford--'the energy cost and carbon-saving benefits of combined heat and power are difficult to match where there is a large heating/cooling demand over extended periods'. In this article, he explains how hospitals and other busy healthcare facilities thus 'make ideal bedfellows' for CHP, and outlines the key criteria and considerations, such as sizing, for healthcare engineers, when looking to specify such a system.

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. .

Analysis of the impact of Heat-to-Power Ratio for a SOFC-based mCHP system for residential application under different climate regions in Europe

DEFF Research Database (Denmark)

Liso, Vincenzo; Zhao, Yingru; Brandon, Nigel

2011-01-01

In this paper, the ability of a micro combined heat and power (mCHP) system to cover the heat and electricity demand of a single-family residence is investigated. A solid oxide fuel cell based mCHP system coupled with a hot water storage tank is analyzed. The energy profiles of single-family hous......In this paper, the ability of a micro combined heat and power (mCHP) system to cover the heat and electricity demand of a single-family residence is investigated. A solid oxide fuel cell based mCHP system coupled with a hot water storage tank is analyzed. The energy profiles of single...... according to the summer energy demand. The winter energy demand shows a Heat-to-Power Ratio which cannot be covered by the mCHP unit alone. To ensure that the mCHP system meets both the thermal and electrical energy demand over the entire year, an auxiliary boiler and a hot water storage tank need...

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.

Optimal design and operation of a syngas-fuelled SOFC micro CHP system for residential applications in different climate zones in China

DEFF Research Database (Denmark)

Yang, Wenyuan; Zhao, Yingru; Liso, Vincenzo

2014-01-01

under difference climate conditions to ensure that it is well matched with the local heat-to-power ratio. The aim of this study is to investigate the optimal design and operation of a syngas-fuelled SOFC micro-CHP system for small households located in five different climate zones in China. The ability...... of the micro-CHP to cover the heat and electricity demand of a 70 m2 single-family apartment with an average number of occupants of 3 is evaluated. A detailed model of the micro-CHP unit coupled with a hot water storage tank and an auxiliary boiler is developed. System design trade-offs are discussed...

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

Energy Technology Data Exchange (ETDEWEB)

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

1995-05-01

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

Multi-Objective Analysis of a CHP Plant Integrated Microgrid in Pakistan

Directory of Open Access Journals (Sweden)

Asad Waqar

2017-10-01

Full Text Available In developing countries like Pakistan, the capacity shortage (CS of electricity is a critical problem. The frequent natural gas (NG outages compel consumers to use electricity to fulfill the thermal loads, which ends up as an increase in electrical load. In this scenario, the authors have proposed the concept of a combined heat & power (CHP plant to be a better option for supplying both electrical and thermal loads simultaneously. A CHP plant-based microgrid comprising a PV array, diesel generators and batteries (operating in grid-connected as well as islanded modes has been simulated using the HOMER Pro software. Different configurations of distributed generators (DGs with/without batteries have been evaluated considering multiple objectives. The multiple objectives include the minimization of the total net present cost (TNPC, cost of generated energy (COE and the annual greenhouse gas (GHG emissions, as well as the maximization of annual waste heat recovery (WHR of thermal units and annual grid sales (GS. These objectives are subject to the constraints of power balance, battery operation within state of charge (SOC limits, generator operation within capacity limits and zero capacity shortage. The simulations have been performed on six cities including Islamabad, Lahore, Karachi, Peshawar, Quetta and Gilgit. The simulation results have been analyzed to find the most optimal city for the CHP plant integrated microgrid.

Experimental development, 1D CFD simulation and energetic analysis of a 15 kw micro-CHP unit based on reciprocating internal combustion engine

International Nuclear Information System (INIS)

Muccillo, M.; Gimelli, A.

2014-01-01

Cogeneration is commonly recognized as one of the most effective solutions to achieve the increasingly stringent reduction in primary energy consumption and greenhouse emissions. This characteristic led to the adoption of specific directives promoting this technique. In addition, a strategic role in power reliability is recognized to distributed generation. The study and prototyping of cogeneration plants, therefore, has involved many research centres. This paper deals with energetic aspects of CHP referring to the study of a 15 kW micro-CHP plant based on a LPG reciprocating engine designed, built and grid connected. The plant consists of a heat recovery system characterized by a single water circuit recovering heat from exhaust gases, from engine coolant and from the energy radiated by the engine within the shell hosting the plant. Some tests were carried out at whole open throttle and the experimental data were collected. However it was needed to perform a 1D thermo-fluid dynamics simulation of the engine to completely characterize the micro-CHP. As the heat actually recovered depends on the user's thermal load, particularly from the required temperature's level, a comparison of the results for six types of users were performed: residential, hospital, office, commercial, sports, hotel. Both Italian legislative indexes IRE and LT were evaluated, as defined by A.E.E.G resolution n. 42/02 and subsequent updates, as well as the plant's total Primary Energy Saving. - Highlights: • This paper deals with energetic aspects of CHP referring to the study of a 15 kW micro-CHP plant. • The 15 kW micro-CHP plant is based on a GPL reciprocating engine designed, built and grid connected. • Some tests were carried out at whole open throttle and the experimental data were collected. • It was needed to perform a 1D thermo-fluid dynamics simulation of the engine to completely characterize the micro-CHP. • The analysed solution is particularly suited for

Mississippi State University Cooling, Heating, and Power (Micro-CHP) and Bio-Fuel Center

Energy Technology Data Exchange (ETDEWEB)

Mago, Pedro [Mississippi State Univ., Mississippi State, MS (United States); Newell, LeLe [Mississippi State Univ., Mississippi State, MS (United States)

2014-01-31

Between 2008 and 2014, the U.S. Department of Energy funded the MSU Micro-CHP and Bio-Fuel Center located at Mississippi State University. The overall objective of this project was to enable micro-CHP (micro-combined heat and power) utilization, to facilitate and promote the use of CHP systems and to educate architects, engineers, and agricultural producers and scientists on the benefits of CHP systems. Therefore, the work of the Center focused on the three areas: CHP system modeling and optimization, outreach, and research. In general, the results obtained from this project demonstrated that CHP systems are attractive because they can provide energy, environmental, and economic benefits. Some of these benefits include the potential to reduce operational cost, carbon dioxide emissions, primary energy consumption, and power reliability during electric grid disruptions. The knowledge disseminated in numerous journal and conference papers from the outcomes of this project is beneficial to engineers, architects, agricultural producers, scientists and the public in general who are interested in CHP technology and applications. In addition, more than 48 graduate students and 23 undergraduate students, benefited from the training and research performed in the MSU Micro-CHP and Bio-Fuel Center.

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.

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

Automotive Stirling engine Market and Industrial Readiness Program (MIRP), phase 1

Science.gov (United States)

1982-05-01

A program, begun in 1978, has the goal of transferring Stirling engine technology from United Stirling of Sweden to the US and, then, following design, fabrication, and prototype testing, to secure US manufacturers for the engine. The ultimate objective is the large-scale commercial use of the Automotive Stirling Engine (ASE) by the year 2000. The fist phase of the Market and Industrial Readiness Program for the ASE was concerned with defining the market, product, economic and technical factors necessary to be addressed to assure a reasonable chance of ultimate commercial acceptance. Program results for this first phase are reported and discussed. These results pertain to licensing strategy development, economic analysis, market factors, product planning, market growth, cost studies, and engine performance as measured by fuel economy using conventional fuels and by vehicle speed and acceleration characteristics.

Heat Pumps in CHP Systems

DEFF Research Database (Denmark)

Ommen, Torben Schmidt

that three configurations are particular advantageous, whereas the two remaining configurations result in system performance close to or below what may be expected from an electric heater. One of the three advantageous configurations is required to be positioned at the location of the heat demand, whereas...... the two remaining can be located at positions with availability of high temperature sources by utilising the DH network to distribute the heat. A large amount of operational and economic constraints limit the applicability of HPs operated with natural working fluids, which may be the only feasible choice...... representation allows infeasible production. Using MIP or NLP optimisation, the number of operation hours and the total production of heat from HPs are significantly increased, as the HPs may be used to shave the load patterns of CHP units in significantly constrained energy systems. A MIP energy system model...

Is micro-CHP price controllable under price signal controlled Virtual Power Plants?

DEFF Research Database (Denmark)

You, Shi; Træholt, Chresten; Poulsen, Bjarne

2011-01-01

As micro-combined heat and power (micro-CHP) systems move towards mass deployment together with other kinds of distributed energy resources (DER), an increasing emphasis has been placed on how to coordinate such a large diversified DER portfolio in an efficient way by the Virtual Power Plant (VPP...... for three different micro-CHP systems to investigate the feasibility of being controlled by price. Such analysis is relevant for both controller designs for micro-CHP systems and VPP related operations. The results indicate that controlling the micro-CHP systems by price is feasible but could result...

Energetic and environmental performance of three biomass upgrading processes integrated with a CHP plant

International Nuclear Information System (INIS)

Kohl, Thomas; Laukkanen, Timo; Järvinen, Mika; Fogelholm, Carl-Johan

2013-01-01

Highlights: ► We simulate CHP-integrated production of wood pellets, torrefied wood pellets and pyrolysis slurry. ► Integration increases operation hours and district heat output by up to 38% and 22%. ► Additionally installed equipment reduces yearly power generation by up to 7%. ► Wood pellet production performs best energetically and environmentally. ► Integrated concepts substantially reduce fuel consumption and CO 2 emissions. - Abstract: In order to react on future expected increased competition on restricted biomass resources, communal combined heat and power (CHP) plants can be integrated with biomass upgrading processes that add valuable products to the portfolio. In this paper, outgoing from a base case, the retrofit integration of production of wood pellets (WPs), torrefied wood pellets (TWPs) and wood fast pyrolysis slurry (PS) with an existing wood-fired CHP plant was simulated. Within the integration concept, free boiler capacity during times of low district heat demands is used to provide energy for the upgrading processes. By detailed part-load modelling, critical process parameters are discussed. With help of a multiperiod model of the heat duration curve, the work further shows the influence of the integration on plant operating hours, electricity production and biomass throughput. Environmental and energetic performance is assessed according to European standard EN 15603 and compared to the base case as well as to stand-alone production in two separate units. The work shows that all three integration options are well possible within the operational limits of the CHP plant. Summarising, this work shows that integration of WP, TWP and PS production from biomass with a CHP plant by increasing the yearly boiler workload leads to improved primary energy efficiency, reduced CO 2 emissions, and, when compared to stand-alone production, also to substantial fuel savings

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.

ANALYSIS OF CHP POTENTIAL AT FEDERAL SITES

Energy Technology Data Exchange (ETDEWEB)

HADLEY, S.W.

2002-03-11

This document was prepared at the request of the U.S. Department of Energy's (DOE's) Federal Energy Management Program (FEMP) under its Technical Guidance and Assistance and Project Financing Programs. The purpose was to provide an estimate of the national potential for combined heat and power (also known as CHP; cogeneration; or cooling, heating, and power) applications at federal facilities and the associated costs and benefits including energy and emission savings. The report provides a broad overview for the U.S. Department of Energy (DOE) and other agencies on when and where CHP systems are most likely to serve the government's best interest. FEMP's mission is to reduce the cost to and environmental impact of the federal government by advancing energy efficiency and water conservation, promoting the use of renewable energy, and improving utility management decisions at federal sites. FEMP programs are driven by its customers: federal agency sites. FEMP monitors energy efficiency and renewable energy technology developments and mounts ''technology-specific'' programs to make technologies that are in strong demand by agencies more accessible. FEMP's role is often one of helping the federal government ''lead by example'' through the use of advanced energy efficiency/renewable energy (EERE) technologies in its own buildings and facilities. CHP was highlighted in the Bush Administration's National Energy Policy Report as a commercially available technology offering extraordinary benefits in terms of energy efficiencies and emission reductions. FEMP's criteria for emphasizing a technology are that it must be commercially available; be proven but underutilized; have a strong constituency and momentum; offer large energy savings and other benefits of interest to federal sites and FEMP mission; be in demand; and carry sufficient federal market potential. As discussed in the report, CHP meets all

Micro-CHP Technologies Roadmap: Meeting 21st Century Residential Energy Needs

Energy Technology Data Exchange (ETDEWEB)

none,

2003-12-01

On June 11-12, 2003, at Greenbelt, Maryland, key stakeholders from industry, government agencies, universities, and others involved in combined heat and power and the residential buildings industry explores solutions to technical, institutional, and market barriers facing micro-combined heat and power systems (mCHP). Participants outlined a desired future for mCHP systems, identified specific interim technology cost and performance targets, and developed actions to achieve the interim targets and vision. This document, The Micro-CHP Technologies Roadmap, is a result of their deliberations. It outlines a set of actions that can be pursued by both the government and industry to develop mCHP appliances for creating a new approach for households to meet their energy needs.

CHP and District Cooling: An Assessment of Market and Policy Potential in India

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01

This report contains an assessment of India's CHP/DC status and recommendations for addressing barriers to allow India to meet its energy efficiency targets. Such barriers include a lack of governmental emphasis on CHP, the absence of a clear methodology for calculating CO2 emission reductions from CHP/DHC, and a tax and duty structure for CHP capital equipment that is not as attractive as for other renewable energy technologies.

Application of an improved operational strategy for a high temperature-proton exchange membrane fuel cell-based micro-combined heat and power system for Danish single-family households

DEFF Research Database (Denmark)

Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

2013-01-01

be justified as compared to other micro-CHP system technologies. The most important findings of this research study indicate that in comparison to non-fuel cell-based micro-CHP systems, such as Stirling Engine-based systems, the proposed system has significantly higher efficiencies. Moreover, the lower heat...

The role of combined heat and power (CHP) in energy and climate policy

International Nuclear Information System (INIS)

Conrad, F.

1993-03-01

In the energy- and environment context CHP is said to be especially energy saving and climate preserving. This report shows that from the standpoint of energy economics as well as under technical aspects this judgement holds true only under special conditions. Depending on the technical parameters, the concrete circumstances of operation and the characteristics of the power plants and heating systems compared to CHP-plants the range of realistic energy savings turns out to be very large. Related overstimations are to a good extend caused by the traditional practice of granting the energetic advantage of CHP exclusively to the district heating. If this advantage is credited to heat and power as equal shares space heating with cogenerated power of 80% efficiency reveals to be very energy conserving. The uno actu utilization of cogenerated heat and power, for the same purpose could facilitate the expansion of CHP, since the problems related to the feeding of cogenerated power into the grid for general purposes would disappear. The second main issue of this report concerns the abatement of CO 2 -emissions with the aid of CHP. Fuelled with natural gas, CHP-plants are attractive instruments for climate policy. This is especially true if CHP is compared to old coal-based power plants and oil-fuelled old heating systems. In the FRG, however, hard coal, and not natural gas, will be the main fuel for future CHP, lowering its CO 2 -advantage considerably. On the other hand high efficient combi-power plants (gas turbine plus condensing turbine) and gas heating systems have to be included in the comparative analyse. Compared to these advanced systems the CO 2 -characteristics of CHP are inferior. Moreover, the specific CO 2 -advantage of natural gas is better used by such modern mono systems rather than CHP-plants. (orig.) [de

Optimization of operation for combined heat and power plants - CHP plants - with heat accumulators using a MILP formulation

Energy Technology Data Exchange (ETDEWEB)

Grue, Jeppe; Bach, Inger [Aalborg Univ. (Denmark). Inst. of Energy Technology]. E-mails: jeg@iet.auc.dk; ib@iet.auc.dk

2000-07-01

The power generation system in Denmark is extensively based on small combined heat and power plants (CHP plants), producing both electricity and district heating. This project deals with smaller plants spread throughout the country. Often a heat accumulator is used to enable electricity production, even when the heat demand is low. This system forms a very complex problem, both for sizing, designing and operation of CHP plants. The objective of the work is the development of a tool for optimisation of the operation of CHP plants, and to even considering the design of the plant. The problem is formulated as a MILP-problem. An actual case is being tested, involving CHP producing units to cover the demand. The results from this project show that it is of major importance to consider the operation of the plant in detail already in the design phase. It is of major importance to consider the optimisation of the plant operation, even at the design stage, as it may cause the contribution margin to rise significantly, if the plant is designed on the basis of a de-tailed knowledge of the expected operation. (author)

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…

CHP as a Boiler Replacement Opportunity (Webinar) – April 30, 2013

Science.gov (United States)

This webinar provides information about the benefits of replacing a boiler with a CHP system, describes CHP project analysis and delivery processes, and highlights a case study at Penn State University.

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.

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.

Micro Cooling, Heating, and Power (Micro-CHP) and Bio-Fuel Center, Mississippi State University

Energy Technology Data Exchange (ETDEWEB)

Louay Chamra

2008-09-26

Initially, most micro-CHP systems will likely be designed as constant-power output or base-load systems. This implies that at some point the power requirement will not be met, or that the requirement will be exceeded. Realistically, both cases will occur within a 24-hour period. For example, in the United States, the base electrical load for the average home is approximately 2 kW while the peak electrical demand is slightly over 4 kW. If a 3 kWe micro- CHP system were installed in this situation, part of the time more energy will be provided than could be used and for a portion of the time more energy will be required than could be provided. Jalalzadeh-Azar [6] investigated this situation and presented a comparison of electrical- and thermal-load-following CHP systems. In his investigation he included in a parametric analysis addressing the influence of the subsystem efficiencies on the total primary energy consumption as well as an economic analysis of these systems. He found that an increase in the efficiencies of the on-site power generation and electrical equipment reduced the total monthly import of electricity. A methodology for calculating performance characteristics of different micro-CHP system components will be introduced in this article. Thermodynamic cycles are used to model each individual prime mover. The prime movers modeled in this article are a spark-ignition internal combustion engine (Otto cycle) and a diesel engine (Diesel cycle). Calculations for heat exchanger, absorption chiller, and boiler modeling are also presented. The individual component models are then linked together to calculate total system performance values. Performance characteristics that will be observed for each system include maximum fuel flow rate, total monthly fuel consumption, and system energy (electrical, thermal, and total) efficiencies. Also, whether or not both the required electrical and thermal loads can sufficiently be accounted for within the system

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

Science.gov (United States)

Oriti, Salvatore M.

2012-01-01

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

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.

International off-grid market assessment for dish/Stirling systems

International Nuclear Information System (INIS)

Lilienthal, P.; Campbell, K.

1998-01-01

Several features of dish/Stirling technology offer potential advantages for off-grid power generation. Dish/Stirling technology's size, modularity, the ease with which it might be hybridized with a storable fuel, the elimination of batteries and inverters, and the production of pure sine-wave AC power without a diesel all indicate that a reliable dish/Stirling module could fit well into an off-grid electrification scheme. At the same time, a combination of factors makes success in off-grid applications difficult, regardless of the technology under consideration. Obstacles include consumer expectations (formed by a long history of subsidies) that electricity should be cheap, existing support infrastructure, and the economic resources of rural communities. Cost is always a factor, but reliability and access to parts and service have been more significant barriers so far in the establishment of renewables. This paper summarizes a much more extensive market assessment. Initial research indicates that a reliable 25 kW dish/Stirling system with reasonable servicing requirements could compete well with other off-grid power systems at a cost considered achievable at early production levels ($3,500 per kW). However, by itself the off-grid power market in regions with adequate solar insolation and inviting political regimes does not justify an adequate scale of production. It is estimated that the aggregate market in five of the largest and most promising countries for which adequate information was available could be 23,000 to 38,000 units of 25 kW dish/Stirling systems. Including the rest of the developing world could more than double this number. However, at a reasonable initial market penetration rate of 1% per year this market is not sufficient, by itself, for the mass production rates required to achieve the necessary economies of scale

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. .

Screening of CHP Potential at Federal Sites in Select Regions of the U.S.

Energy Technology Data Exchange (ETDEWEB)

Energy Nexus Group, . .

2002-02-25

Combined Cooling Heat and Power (CHP) is a master term for onsite power generation technologies that sequentially produce electrical or mechanical energy and useful thermal energy. Some form of CHP has existed for more than 100 years and it is now achieving a greater level of acceptance due to an increasing need for reliable power service and energy cost management. Capturing and using the heat produced as a byproduct of generating electricity from fuel sources increases the usable energy that can be obtained from the original fuel source. CHP technologies have the potential to reduce energy consumption through increased efficiency--decreasing energy bills as well as pollution. The EPA recognizes CHP as a potent climate change mitigation measure. The U.S. Department of Energy (D.O.E.) Federal Energy Management Program (FEMP) is assisting Federal agencies to realize their energy efficiency goals. CHP is an efficiency measure that is receiving growing attention because of its sizable potential to provide efficiency, environmental, and reliability benefits. CHP therefore benefits the host facility, the electric infrastructure, and the U.S. society as a whole. This report and study seeks to make a preliminary inquiry into near term CHP opportunities for federal facilities in selected U.S. regions. It offers to help focus the attention of policy makers and energy facility managers on good candidate facilities for CHP. First, a ranked list of high potential individual sites is identified. Then, several classes of federal facilities are identified for the multiple opportunities they offer as a class. Recommendations are then offered for appropriate next steps for the evaluation and cost effective implementation of CHP. This study was designed to ultimately rank federal facilities in terms of their potential to take advantage of CHP economic and external savings in the near term. In order to best serve the purposes of this study, projections have been expressed in terms of

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.

Examination of energy price policies in Iran for optimal configuration of CHP and CCHP systems based on particle swarm optimization algorithm

International Nuclear Information System (INIS)

Tichi, S.G.; Ardehali, M.M.; Nazari, M.E.

2010-01-01

The current subsidized energy prices in Iran are proposed to be gradually eliminated over the next few years. The objective of this study is to examine the effects of current and future energy price policies on optimal configuration of combined heat and power (CHP) and combined cooling, heating, and power (CCHP) systems in Iran, under the conditions of selling and not-selling electricity to utility. The particle swarm optimization algorithm is used for minimizing the cost function for owning and operating various CHP and CCHP systems in an industrial dairy unit. The results show that with the estimated future unsubsidized utility prices, CHP and CCHP systems operating with reciprocating engine prime mover have total costs of 5.6 and $2.9x10 6 over useful life of 20 years, respectively, while both systems have the same capital recovery periods of 1.3 years. However, for the same prime mover and with current subsidized prices, CHP and CCHP systems require 4.9 and 5.2 years for capital recovery, respectively. It is concluded that the current energy price policies hinder the promotion of installing CHP and CCHP systems and, the policy of selling electricity to utility as well as eliminating subsidies are prerequisites to successful widespread utilization of such systems.

Stirling engine electric hybrid vehicle propulsion system conceptual design study. Final report

Energy Technology Data Exchange (ETDEWEB)

Dochat, G; Artiles, A; Killough, J; Ray, A; Chen, H S

1978-08-01

Results of a six-month study to characterize a series Stirling engine electric hybrid vehicle propulsion system are presented. The Stirling engine was selected as the heat conversion element to exploit the high efficiency (> .36), low pollution, multi-fuel and quiet operation of this machine. A free-piston Stirling engine driving a linear alternator in a hermatically sealed enclosure was chosen to gain the reliability, long life, and maintenance free characteristics of a sealed unit. The study performs trade off evaluations, selection of engine, battery, motor and inverter size, optimization of components, and develops a conceptual design and characterization of the total propulsion system. The conclusion of the study is that a Stirling engine electric hybrid propulsion system can be used successfully to augment the battery storage of a passenger vehicle and will result in significant savings of petroleum energy over present passenger vehicles. The performance and range augmentation of the hybrid design results in significant improvements over an all electric vehicle. The hybrid will be capable of performing 99% of the passenger vehicle annual trip distribution requirements with extremely low fuel usage. (TFD)

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.

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.

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

CHP plant Legionowo Poland - Final report

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-12-01

In 1997, a new Energy Law was passed in Poland. An important element of the law is that local energy planning is made obligatory. The law describes obligatory tasks and procedures for Polish municipalities related to planning and organisation of the energy sector. With the objective of supporting the Polish municipalities in their obligations according to the energy law of 1997, the project 'Energy Planning in Poland at Municipal Level - Support to Decision Makers' was launched. As part of the project, Municipal Guideline Reports have been elaborated for three model municipalities. These guidelines present the basis for the Energy Supply Plans in these municipalities. For the city of Legionowo, the following was recommended: 1. The planning processes initiated during the project should be continues/followed up, 2. Master Plan for the district heating system should be prepared, 3. The possibilities of establishment of a major natural gas-fired CHP plant of the Combined Cycle type should be investigated. The present report is the final Master Plan based on the following reports: Master Plan for Legionowo - Status Report; Master Plan for Legionowo - Hydraulic Analysis; CHP Plant Legionowo Poland - CHP Feasibility Analysis. The final Master Plan describes the status in the DH Company in Legionowo, possible improvements and an investment plan for the selected scenario. (BA)

Combined Heat & Power Using the Infinia Concentrated Solar - CHP PowerDish System

Science.gov (United States)

2013-08-01

forward operating base FPSE Free Piston Stirling Engine GHG greenhouse gas IOU investor-owned utility kW kilowatt kWac kilowatt alternating...Free Piston Stirling Engine (FPSE) for military, commercial, and space applications for almost 30 years. As Infinia developed a commercial product...6 Figure 2. Free-piston Stirling generator. ................................................................................ 6 Figure 3

The Significance of a Building’s Energy Consumption Profiles for the Optimum Sizing of a Combined Heat and Power (CHP System—A Case Study for a Student Residence Hall

Directory of Open Access Journals (Sweden)

Khuram Pervez Amber

2018-06-01

Full Text Available University buildings, such as student residence halls with year-round consistent energy demands, offer strong opportunities for Combined Heat and Power (CHP systems. The economic and environmental feasibility of a CHP project is strongly linked with its optimum sizing. This study aims to undertake such an assessment for a CHP system for a student residence hall located in London, the United Kingdom (UK. The study also aims to undertake a sensitivity analysis to investigate the effect of different parameters on the project’s economics. Necessary data are collected via interviews with the University’s Energy Manager. Modeling of the CHP system is performed using the London South Bank University (LSBU, London, the UK CHP model. Results demonstrate that optimum sizing of CHP is crucial for achieving higher economic and environmental benefits and strongly depends on the authenticity of the energy consumption data, based on which the CHP is being sized. Use of incorrect energy data could result in an undersized or oversized CHP system, where an oversized system will result in higher negative results compared to an undersized system. Finally, Monto Carlo statistical analysis shows that electricity price is the significant factor that could affect the project’s economics. With an increasing spark gap, the payback period decreases, and vice versa.

Modelling Danish local CHP on market conditions

DEFF Research Database (Denmark)

Ravn, Hans V.; Riisom, Jannik; Schaumburg-Müller, Camilla

2004-01-01

with the liberalisation process of the energy sectors of the EU countries, it is however anticipated that Danish local CHP are to begin operating on market conditions within the year 2005. This means that the income that the local CHPs previously gained from selling electricity at the feed-in tariff is replaced in part...... the consequences of acting in a liberalised market for a given CHP plant, based on the abovementioned bottom-up model. The key assumption determining the bottom line is the electricity spot price. The formation of the spot price in the Nordic area depends heavily upon the state of the water reservoirs in Norway...

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.

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.

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.

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.

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.

Combined Heat & Power Using the Infinia Concentrated Solar CHP PowerDish System

Science.gov (United States)

2013-08-01

Executive Orders FOB - Forward Operating Base FPSE - Free Piston Stirling Engine GHG - Greenhouse Gas ICC - International Code Council IMA... Stirling Engine (FPSE) for military, commercial, and space applications for almost 30 years. These developments have included multiple fuel types...product for its Free Piston Stirling Engine operating on solar energy for electricity production, called the PowerDishTM, a reasonable extension for

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

Science.gov (United States)

Wilson, Dcott D.

2012-01-01

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

Integration of hydrothermal carbonization and a CHP plant: Part 2 –operational and economic analysis

International Nuclear Information System (INIS)

Saari, Jussi; Sermyagina, Ekaterina; Kaikko, Juha; Vakkilainen, Esa; Sergeev, Vitaly

2016-01-01

Wood-fired combined heat and power (CHP) plants are a proven technology for producing domestic, carbon-neutral heat and power in Nordic countries. One drawback of CHP plants is the low capacity factors due to varying heat loads. In the current economic environment, uncertainty over energy prices creates also uncertainty over investment profitability. Hydrothermal carbonization (HTC) is a promising thermochemical conversion technology for producing an improved, more versatile wood-based fuel. Integrating HTC with a CHP plant allows simplifying the HTC process and extending the CHP plant operating time. An integrated polygeneration plant producing three energy products is also less sensitive to price changes in any one product. This study compares three integration cases chosen from the previous paper, and the case of separate stand-alone plants. The best economic performance is obtained using pressurized hot water from the CHP plant boiler drum as HTC process water. This has the poorest efficiency, but allows the greatest cost reduction in the HTC process and longest CHP plant operating time. The result demonstrates the suitability of CHP plants for integration with a HTC process, and the importance of economic and operational analysis considering annual load variations in sufficient detail. - Highlights: • Integration of wood hydrothermal carbonization with a small CHP plant studied. • Operation and economics of three concepts and stand-alone plants are compared. • Sensitivity analysis is performed. • Results show technical and thermodynamic analysis inadequate and misleading alone. • Minimizing HTC investment, extending CHP operating time important for profitability.

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.

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

MICRO-CHP System for Residential Applications

Energy Technology Data Exchange (ETDEWEB)

Joseph Gerstmann

2009-01-31

This is the final report of progress under Phase I of a project to develop and commercialize a micro-CHP system for residential applications that provides electrical power, heating, and cooling for the home. This is the first phase of a three-phase effort in which the residential micro-CHP system will be designed (Phase I), developed and tested in the laboratory (Phase II); and further developed and field tested (Phase III). The project team consists of Advanced Mechanical Technology, Inc. (AMTI), responsible for system design and integration; Marathon Engine Systems, Inc. (MES), responsible for design of the engine-generator subsystem; AO Smith, responsible for design of the thermal storage and water heating subsystems; Trane, a business of American Standard Companies, responsible for design of the HVAC subsystem; and AirXchange, Inc., responsible for design of the mechanical ventilation and dehumidification subsystem.

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)

Elimination of restraints on the propagation of combined heat and power (CHP) generation systems in Switzerland; Beseitigung von Hemmnissen bei der Verbreitung von Waermekraftkopplung (WKK) in der Schweiz

Energy Technology Data Exchange (ETDEWEB)

Rieder, S.; Landis, F. [Interface Politikstudien Forschung Beratung, Luzern (Switzerland); Lienhard, A.; Marti Locher, F. [Universitaet Bern, Kompetenzzentrum fuer Public Management (KPM), Bern (Switzerland); Krummenacher, S. [Enerprice Partners AG, Technopark Luzern, Root Laengenbold (Switzerland)

2009-04-15

This report for the Swiss Federal Office of Energy (SFOE) discusses the results of study initiated by the SFOE that was to investigate the reasons for the low level of proliferation of CHP technology in Switzerland. The two main questions asked - which factors inhibit the use of CHP in particular application areas and which energy-policy measures can remove such obstacles - are discussed. The use of CHP in various areas of application from waste incineration plants through to units used in residential buildings is analysed and commented on. Recommendations on measures that can be taken to enhance the use of CHP are discussed. Three strategy variants available to the public services area are presented and discussed. It is noted that a consensus between players in the technical and political areas is necessary

Implementation of a Sage-Based Stirling Model Into a System-Level Numerical Model of the Fission Power System Technology Demonstration Unit

Science.gov (United States)

Briggs, Maxwell H.

2011-01-01

The Fission Power System (FPS) project is developing a Technology Demonstration Unit (TDU) to verify the performance and functionality of a subscale version of the FPS reference concept in a relevant environment, and to verify component and system models. As hardware is developed for the TDU, component and system models must be refined to include the details of specific component designs. This paper describes the development of a Sage-based pseudo-steady-state Stirling convertor model and its implementation into a system-level model of the TDU.

Thermodynamic evaluation of CHP (combined heat and power) plants integrated with installations of coal gasification

International Nuclear Information System (INIS)

Ziębik, Andrzej; Malik, Tomasz; Liszka, Marcin

2015-01-01

Integration of a CHP steam plant with an installation of coal gasification and gas turbine leads to an IGCC-CHP (integrated gasification combined cycle-combined heat and power). Two installations of coal gasification have been analyzed, i.e. pressurized entrained flow gasifier – case 1 and pressurized fluidized bed gasifier with CO_2 recirculation – case 2. Basing on the results of mathematical modelling of an IGCC-CHP plant, the algorithms of calculating typical energy indices have been derived. The following energy indices are considered, i.e. coefficient of heat performance and relative savings of chemical energy of fuels. The results of coefficients of heat performance are contained between 1.87 and 2.37. Values exceeding 1 are thermodynamically justified because the idea of cogeneration of heat and electricity based on combining cycles of the heat engine and heat pump the efficiency of which exceeds 1. Higher values concerning waste heat replace more thermodynamically effective sources of heat in CHP plants. Relative savings of the chemical energy of fuels are similar in both cases of IGCC-CHP plants and are contained between the lower value of the CHP (combined heat and power) plants fuelled with coal and higher value of CHP plants fired with natural gas. - Highlights: • Energy savings of fuel is an adequate measure of cogeneration. • Relative energy savings of IGCC-CHP is near the result of a gas and steam CHP. • COHP (coefficient of heat performance) can help to divide fuel between heat fluxes. • Higher values of COHP in the case of waste heat recovery result from the lower thermal parameters.

Opposed piston linear compressor driven two-stage Stirling Cryocooler for cooling of IR sensors in space application

Science.gov (United States)

Bhojwani, Virendra; Inamdar, Asif; Lele, Mandar; Tendolkar, Mandar; Atrey, Milind; Bapat, Shridhar; Narayankhedkar, Kisan

2017-04-01

A two-stage Stirling Cryocooler has been developed and tested for cooling IR sensors in space application. The concept uses an opposed piston linear compressor to drive the two-stage Stirling expander. The configuration used a moving coil linear motor for the compressor as well as for the expander unit. Electrical phase difference of 80 degrees was maintained between the voltage waveforms supplied to the compressor motor and expander motor. The piston and displacer surface were coated with Rulon an anti-friction material to ensure oil less operation of the unit. The present article discusses analysis results, features of the cryocooler and experimental tests conducted on the developed unit. The two-stages of Cryo-cylinder and the expander units were manufactured from a single piece to ensure precise alignment between the two-stages. Flexure bearings were used to suspend the piston and displacer about its mean position. The objective of the work was to develop a two-stage Stirling cryocooler with 2 W at 120 K and 0.5 W at 60 K cooling capacity for the two-stages and input power of less than 120 W. The Cryocooler achieved a minimum temperature of 40.7 K at stage 2.

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.

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

Science.gov (United States)

Oriti, Salvatore M.

2012-01-01

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

A microeconomic analysis of decentralized small scale biomass based CHP plants—The case of Germany

International Nuclear Information System (INIS)

Wittmann, Nadine; Yildiz, Özgür

2013-01-01

Alternative energy sources, such as biomass CHP plants, have recently gained significantly in importance and action is due both on the large scale corporate level and on the small scale. Hence, making the scope and economic outline of such projects easily intelligible without losing relevant details seems a key factor to further promote the necessary developments. The model setup presented in this paper may therefore serve as a starting point for generating numerical results based on real life cases or scenarios. Its focus lies on the economic analysis of decentralized biomass CHP plants. It presents a new approach to analyzing the economic aspects of biomass CHP plants implementing a formal microeconomic approach. As Germany claims a leading role in the market for renewable energy production, the paper also takes a closer look on the effects of German energy policy with respect to biomass CHP plants. - Highlights: • A formal microeconomic model is used to analyse a decentralized biomass CHP plant. • Model setup is used to generate numerical results based on real life scenarios. • Nested CES production function is a new approach to model economics of biomass CHP. • Analysis presents insight into microeconomics and cost drivers of biomass CHP. • Evaluation of energy policy design with respect to environmental policy goals

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.

Analysis of the location for peak heating in CHP based combined district heating systems

International Nuclear Information System (INIS)

Wang, Haichao; Lahdelma, Risto; Wang, Xin; Jiao, Wenling; Zhu, Chuanzhi; Zou, Pinghua

2015-01-01

Combined heat and power (CHP) is the main technology for providing the base load of district heating in China. However, CHP is not efficient for providing the peak load; instead, a peak boiler with high efficiency could be used to compensate the peak load. This paper studies how the location of the peak boiler can affect the energy efficiency and economic performance of such CHP based combined district heating system. Firstly, the connection mode and the control strategy for different peak heating locations are analyzed. Then the effect of the peak boiler's location on the initial investment of the network and the cost for distributing heat is studied. The objective is to place the peak boiler in a location where the overall costs are the smallest. Following this rule, the results indicate that the peak boiler should be located at the CHP plant if that allows using cheaper ‘self-use electricity’ in CHP for distributing the heat. However, if the market electricity price is used everywhere, or if energy efficiency is more emphasized, the location of the peak boiler should be closer to the users with dense heat loads. - Highlights: • Location for peak heating in the CHP based combined DH system is studied. • Regulation or control strategies for combined DH are summarized. • The heat load duration curve for combined DH is demonstrated. • Network design for combined DH with peak boiler outside of the CHP is analyzed

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.

Dynamic analysis of PEMFC-based CHP systems for domestic application

International Nuclear Information System (INIS)

Barelli, L.; Bidini, G.; Gallorini, F.; Ottaviano, A.

2012-01-01

Highlights: ► Dynamic model of a CHP energy system based on a PEM fuel cell was developed. ► The CHP system behavior at variable electrical and thermal load was investigated. ► The optimal RH value was assessed maximizing PEMFC performance through simulations. ► The system best operating conditions are characterized by a RH value equal to 50%. -- Abstract: Fuel cell-based CHP systems for distributed residential power generation represent an interesting alternative to traditional thermoelectric plants. This is mainly due to the high efficiency obtainable in the production of electricity and heat in a decentralised, quiet and environmental friendly way. The current paper focuses on the development, in Matlab®Simulink environment, of a complete dynamic model of a residential cogenerative (CHP) energy system consisting of the Proton Exchange Membrane fuel cell (PEMFC), fuel processor, heat exchangers, humidifier and auxiliary hot water boiler. The target of the study is the investigation through such a model of the behavior of CHP systems based on fuel cell (FC) at variable electrical and thermal load, in reference to typical load curves of residential users. With the aim to evaluate the system performance (efficiency, fuel consumption, hot water production, response time) and then to characterize its better operating conditions with particular attention to air relative humidity, suitable simulations were carried out. They are characterized by the following of a typical electrical load trend and in relation to two different thermal load profiles. The dynamic model presented in this paper has allowed to observe the fully functioning of the FC based system under variable loads and it has permitted to design appropriate control logics for this system.

Research results from a prototype for power generation from low temperature heat sources in small and medium sized sawmills

Energy Technology Data Exchange (ETDEWEB)

Tveit, Tor-Martin; Hoeeg, Arne; Asphjell, Trond-Atle; Horn, Henning

2010-07-01

In this paper we present research results from a low temperature power generation unit prototype, SPP 2-67A, installed at the timber company Moelven Eidsvold Vaerk in Norway. The power generation unit is a Stirling cycle reciprocating engine connected to a generator, which is designed to combine the mature technology for high temperature Stirling engines (as seen for instance as air independent propulsion (AIP) units in submarines) and recent academic work on low temperature Stirling engines. The power generation unit is installed in a boiler room at the Moelven Eidsvold Vaerk plant and uses steam at approximately 1.5 bar pressure as a heat source. The steam is generated in the 5.5 MW biomass-fuelled boiler, where bark of Norway spruce (Picea abies) is the main biofuel. The installation has been intended both to use hot water as a heat sink to demonstrate CHP operation, and cold water from the grid to demonstrate maximum power generation from surplus steam. The installation is part of a research project partly financed by the Research Council of Norway, with the goal of testing new technology to improve the use of bioenergy resources and conversion of heat from biofuels to power. (Author)

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

Science.gov (United States)

Dugala, Gina M.

2010-01-01

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

Risk analysis for CHP decision making within the conditions of an open electricity market

International Nuclear Information System (INIS)

Al-Mansour, Fouad; Kozuh, Mitja

2007-01-01

Decision making under uncertainty is a difficult task in most areas. Investment decisions for combined heat and power production (CHP) are certainly one of the areas where it is difficult to find an optimal solution since the payback period is several years and parameters change due to different perturbing factors of economic and mostly political nature. CHP is one of the most effective measures for saving primary energy and reduction of greenhouse gas emissions. The implementation of EU directives on the promotion of cogeneration based on useful heat demand in the internal energy market will accelerate CHP installation. The expected number of small CHP installations will be very high in the near future. A quick, reliable and simple tool for economic evaluation of small CHP systems is required. Since evaluation is normally made by sophisticated economic computer models which are rather expensive, a simple point estimate economic model was developed which was later upgraded by risk methodology to give more informative results for better decision making. This paper presents a reliable computer model entitled 'Computer program for economic evaluation analysis of CHP' as a tool for analysis and economic evaluation of small CHP systems with the aim of helping the decision maker. The paper describes two methods for calculation of the sensitivity of the economic results to changes of input parameters and the uncertainty of the results: the classic/static method and the risk method. The computer program uses risk methodology by applying RISK software on an existing conventional economic model. The use of risk methodology for economic evaluation can improve decisions by incorporating all possible information (knowledge), which cannot be done in the conventional economic model due to its limitations. The methodology was tested on the case of a CHP used in a smaller hospital

Optimal economic dispatch of FC-CHP based heat and power micro-grids

International Nuclear Information System (INIS)

Nazari-Heris, Morteza; Abapour, Saeed; Mohammadi-Ivatloo, Behnam

2017-01-01

Highlights: • The multi objective economic/environmental heat and power MG dispatch is solved. • The heat and power MG include FC, CHP, boiler, storage system, and heat buffer tank. • Multi objective scheduling of heat and power MG is solved using ε-constraint method. • DR program is employed in the stochastic programming of heat and power MG dispatch. • The uncertainties for load demand and price signals are taken into account. - Abstract: Micro-grids (MGs) are introduced as a solution for distributed energy resource (DER) units and energy storage systems (ESSs) to participate in providing the required electricity demand of controllable and non-controllable loads. In this paper, the authors study the short-term scheduling of grid-connected industrial heat and power MG which contains a fuel cell (FC) unit, combined heat and power (CHP) generation units, power-only unit, boiler, battery storage system, and heat buffer tank. The paper is aimed to solve the multi-objective MG dispatch problem containing cost and emission minimization with the considerations of demand response program and uncertainties. A probabilistic framework based on a scenario method, which is considered for load demand and price signals, is employed to overcome the uncertainties in the optimal energy management of the MG. In order to reduce operational cost, time-of-use rates of demand response programs have been modeled, and the effects of such programs on the load profile have been discussed. To solve the multi-objective optimization problem, the ε-constraint method is used and a fuzzy satisfying approach has been employed to select the best compromise solution. Three cases are studied in this research to confirm the performance of the proposed method: islanded mode, grid-connected mode, and the impact of time of the use-demand response program on MG scheduling.

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.

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.

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.

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

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.

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

Science.gov (United States)

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

1988-01-01

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

DEVELOPMENT OF THE CHP-THERMAL SCHEMES IN CONTEXTS OF THE CONSOLIDATED ENERGY SYSTEM OF BELARUS

Directory of Open Access Journals (Sweden)

V. N. Romaniuk

2015-01-01

Full Text Available The paper deals with the structural specifics of the Belarus Consolidated Energy System capacities in view of their ongoing transfer to the combined-cycle technology, building the nuclear power plant and necessity for the generating capacity regulation in compliance with the load diagram. With the country’s economic complex energy utilization pattern being preserved, the generating capacities are subject to restructuring and the CHP characteristics undergo enhancement inter alia a well-known increase of the specific electricity production based on the heat consumption. Because of this the steam-turbine condensation units which are the traditional capacity regulators for the energy systems with heat power plants dominance are being pushed out of operation. In consequence of this complex of changes the issue of load diagram provision gains momentum which in evidence is relevant to the Consolidated Energy System of Belarus. One of the ways to alleviate acuteness of the problem could be the specific electric energy production cut on the CHP heat consumption with preserving the heat loads and without their handover to the heat generating capacities of direct combustion i.e. without fuel over-burning. The solution lies in integrating the absorption bromous-lithium heat pump units into the CHP thermal scheme. Through their agency low-temperature heat streams of the generator cooling, the lubrication and condensation heat-extraction of steam minimal passing to the condenser systems are utilized. As a case study the authors choose one of the CHPs in the conditions of which the corresponding employment of the said pumps leads to diminution of the fuel-equivalent specific flow-rate by 20−25 g for 1 kW⋅h production and conjoined electric energy generation capacity lowering. The latter will be handed over to other generating capacities, and the choice of them affects economic expediency of the absorption bromous-lithium heat pump-units installation

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. .

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

Alternative depreciation policies for promoting combined heat and power (CHP) development in Brazil

International Nuclear Information System (INIS)

Soares, Jeferson Borghetti; Szklo, Alexandre Salem; Tolmasquim, Mauricio Tiomno

2006-01-01

This paper assessed the economic impact of alternative depreciation methods on the development of combined heat-and-power (CHP) systems in the Brazilian industrial sector. Alternative depreciation methods were proposed and the case study of a Brazilian chemical plant showed that the most effective depreciation method for the promotion of CHP plants in Brazil was the Matheson method with an accelerated depreciation schedule of 7 years. This alternative method was then applied to the Brazilian chemical industry as a whole, increasing its installed capacity in CHP systems by 24%. Therefore, fiscal incentives can be an interesting tool for promoting energy efficiency in the Brazilian industrial sector, promoting the expansion of CHP plants. It reduces government fiscal revenues, but it also induces the technological reposition and improves the feasibility of ventures that are not installed without this kind of incentive

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. .

Local CHP Plants between the Natural Gas and Electricity Systems

DEFF Research Database (Denmark)

Bregnbæk, Lars; Schaumburg-Müller, Camilla

2005-01-01

, and they contribute significantly to the electricity production. CHP is, together with the wind power, the almost exclusive distributed generation in Denmark. This paper deals with the CHP as intermediary between the natural gas system and the electricity system. In particular, the relationship between the peak hour......Local combined heat and power (CHP) plants in Denmark constitute an important part of the national energy conversion capacity. In particular they supply a large share of the district heating networks with heat. At the same time they are important consumers as seen from the gas network system...... characteristics of the electricity and gas systems will be investigated. The point is here that the two systems will tend to have peak demand during the same hours. This is the typical situation, since load is high during the same hours of the day and of the year. Moreover, the random variations in the load...

Procuring Stationary Fuel Cells For CHP: A Guide for Federal Facility Decision Makers

Energy Technology Data Exchange (ETDEWEB)

Stinton, David P [ORNL; McGervey, Joseph [SRA International, Inc.; Curran, Scott [ORNL

2011-11-01

Federal agency leaders are expressing growing interest in using innovative fuel cell combined heat and power (CHP) technology at their sites, motivated by both executive branch sustainability targets and a desire to lead by example in the transition to a clean energy economy. Fuel cell CHP can deliver reliable electricity and heat with 70% to 85% efficiency. Implementing this technology can be a high efficiency, clean energy solution for agencies striving to meet ambitious sustainability requirements with limited budgets. Fuel cell CHP systems can use natural gas or renewable fuels, such as biogas. Procuring Stationary Fuel Cells for CHP: A Guide for Federal Facility Decision Makers presents an overview of the process for planning and implementing a fuel cell CHP project in a concise, step-by-step format. This guide is designed to help agency leaders turn their interest in fuel cell technology into successful installations. This guide concentrates on larger (100 kW and greater) fuel cell CHP systems and does not consider other fuel cell applications such as cars, forklifts, backup power supplies or small generators (<100 kW). Because fuel cell technologies are rapidly evolving and have high up front costs, their deployment poses unique challenges. The electrical and thermal output of the CHP system must be integrated with the building s energy systems. Innovative financing mechanisms allow agencies to make a make versus buy decision to maximize savings. This guide outlines methods that federal agencies may use to procure fuel cell CHP systems with little or no capital investment. Each agency and division, however, has its own set of procurement procedures. This guide was written as a starting point, and it defers to the reader s set of rules if differences exist. The fuel cell industry is maturing, and project developers are gaining experience in working with federal agencies. Technology improvements, cost reductions, and experienced project developers are making

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.

Design of Biomass Combined Heat and Power (CHP Systems based on Economic Risk using Minimax Regret Criterion

Directory of Open Access Journals (Sweden)

Ling Wen Choong

2018-01-01

Full Text Available It is a great challenge to identify optimum technologies for CHP systems that utilise biomass and convert it into heat and power. In this respect, industry decision makers are lacking in confidence to invest in biomass CHP due to economic risk from varying energy demand. This research work presents a linear programming systematic framework to design biomass CHP system based on potential loss of profit due to varying energy demand. Minimax Regret Criterion (MRC approach was used to assess maximum regret between selections of the given biomass CHP design based on energy demand. Based on this, the model determined an optimal biomass CHP design with minimum regret in economic opportunity. As Feed-in Tariff (FiT rates affects the revenue of the CHP plant, sensitivity analysis was then performed on FiT rates on the selection of biomass CHP design. Besides, design analysis on the trend of the optimum design selected by model was conducted. To demonstrate the proposed framework in this research, a case study was solved using the proposed approach. The case study focused on designing a biomass CHP system for a palm oil mill (POM due to large energy potential of oil palm biomass in Malaysia.

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.

An updated assessment of the prospects for fuel cells in stationary power and CHP. An information paper

Energy Technology Data Exchange (ETDEWEB)

Sanderson, T.K. [Future Energy Solutions, Harwell (United Kingdom)

2005-07-01

This report presents updated conclusions of the Department of Trade and Industry's research and development programme to assess the commercial prospects for advanced fuel cells in stationary power and combined heat and power (CHP) systems. The programme has focussed on low temperature solid polymer fuel cells (SPFCs) for transport and combined heat and power (CHP)/distributed power and high temperature solid oxide fuel cells (SOFCs) for CHP/distributed power. As well as assessing the prospects for SPFCs and SOFCs in stationary power and CHP applications, the report examines those for molten carbonate fuel cells (MCFCs) and phosphoric acid fuel cells (PAFCs). The report provides an assessment of the status of technology development for these different types of fuel cells in terms of applications to stationary power and CHP, and offers estimates of market potential for SOFCs in CHP markets, SPFCs in CHP markets and SOFCs in distributed power generation markets. Both large SPFC and SOFC CHP systems require further development to deliver the necessary cost reductions in materials and manufacturing processes before pre-commercial sales can begin. The routes taken by different manufacturers and their choice of preferred technology are explained. A discussion of the prospects and barriers for fuel cell cars concludes that while cost reduction is a major barrier to the successful commercialisation of fuel cells, there are insufficient data available from operating fuel cells systems (other than PAFC) in stationary power and CHP applications to assess the economic attractiveness of fuel cells compared with existing systems. More field trials are required to confirm energy and environmental performance in such applications and to evaluate operational and economic performance under commercial operating conditions. Such field trials could also provide a focus for the required developments in fuel cells for stationary power/CHP systems.

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.

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.

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

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.

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

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

Energy versus economic effectiveness in CHP (combined heat and power) applications: Investigation on the critical role of commodities price, taxation and power grid mix efficiency

International Nuclear Information System (INIS)

Comodi, Gabriele; Rossi, Mosè

2016-01-01

Starting from PES (primary energy saving) and CSR (cost saving ratio) definitions the work pinpoints a “grey area” in which CHP (combined heat and power – cogeneration) units can operate with profit and negative PES. In this case, CHP can be profitably operated with lower efficiency with respect to separate production of electrical and thermal energy. The work defines the R-index as the ratio between the cost of fuel and electricity. The optimal value of R-index for which CHP units operate with both environmental benefit (PES > 0) and economic profitability (CSR > 0) is the reference value of electrical efficiency, η_e_l_-_r_e_f, of separate production (national power grid mix). As a consequence, optimal R-index varies from Country to Country. The work demonstrates that the value of R corresponds to the minimum value of electrical efficiency for which any power generator operates with profit. The paper demonstrates that, with regard to the profitability of cogeneration, the ratio between the cost of commodities is more important than their absolute value so that different taxation of each commodity can be a good leverage for energy policy makers to promote high efficiency cogeneration, even in the absence of an incentive mechanism. The final part of the study presents an analysis on micro-CHP technologies payback times for different European Countries. - Highlights: • Investigation of the grey area where CHP profitably operates also with negative PES. • Study starts from definition of primary energy saving PES and cost saving ratio CSR. • Definition of the R-index as the ratio between the cost of fuel and electricity. • The optimal value of R for which the “grey area” disappears is R = η_e_l_-_r_e_f. • R is also the value of η_e_l for which any electric generator profitably operates.

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.

SOFC/TEG hybrid mCHP system. Final report

Energy Technology Data Exchange (ETDEWEB)

2012-03-15

The starting point for this project have been the challenge has been to develop a cost effective solution with long term stability. This is where a focused effort in a strong consortium covering material research, module development and manufacture as well as device design and optimization can make a real difference. In March 2010 the SOFTEG phase II project was initiated and a cooperation organization was established to implement the project as a development and demonstration project involving the staff from all project partners. The project is now completed with excellent and documented outcome. The final results by Alpcon have been demonstration as a TEG-based mCHP system calls CHP Dual Engine Power System, which will be applicable as both a standalone TEG-CHP hybrid system, but also as an auxiliary power unit and power booster for the SOFC system. However the SOFC system cannot cover the household's heat demand alone so it is necessary to combine a SOFC system together with a water heater/boiler system to cover the peak heat demand of a residential house or a complex building. The SOFTEG project partners achieved significant results that mainly can be outlined as following: 1) University of Aarhus has improved the thermal stability of ZnSb by optimizing the concentration of Nano composite material. 2) The grain size and its influence on the sintering process by spark plasma method are investigated by Aarhus University, but further work seems to be necessary. 3) The TE material is going to commercialization by Aarhus University. 4) Aalborg University has prepared simulation tools for complex thermoelectric simulation in non-steady state condition. 5) The new type DCDC interleaved converter using the MPPT system for optimal power tracing is designed, build and tested by Aalborg University in cooperation with Alpcon. This task is included overall system design, control system implementation and power electronic control design. 6) Full scale practical

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.

Sizing Combined Heat and Power Units and Domestic Building Energy Cost Optimisation

OpenAIRE

Dongmin Yu; Yuanzhu Meng; Gangui Yan; Gang Mu; Dezhi Li; Simon Le Blond

2017-01-01

Many combined heat and power (CHP) units have been installed in domestic buildings to increase energy efficiency and reduce energy costs. However, inappropriate sizing of a CHP may actually increase energy costs and reduce energy efficiency. Moreover, the high manufacturing cost of batteries makes batteries less affordable. Therefore, this paper will attempt to size the capacity of CHP and optimise daily energy costs for a domestic building with only CHP installed. In this paper, electricity ...

Combustion Turbine CHP System for Food Processing Industry

Energy Technology Data Exchange (ETDEWEB)

None

2010-10-01

This factsheet describes a combined heat and power (CHP) demonstration project that reduces the energy costs and environmental impact of a plant while easing congestion on the constrained Northeast power grid.

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

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)

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.

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.

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.

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

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.

Thermodynamic, ecological and economic aspects of the use of the gas turbine for heat supply to the stripping process in a supercritical CHP plant integrated with a carbon capture installation

International Nuclear Information System (INIS)

Bartela, Łukasz; Skorek-Osikowska, Anna; Kotowicz, Janusz

2014-01-01

Highlights: • Variants of integration of CHP plant with CCS and gas turbine unit were analyzed. • The simulations of operation of plants under changing load were realized. • Conditions of competitiveness for all solutions were identified. • Integration can be profitable if prices of allowance will reach values >60 €/MgCO 2 . - Abstract: This paper presents the results of thermodynamic and economic analyses for eight variants of a combined heat and power (CHP) plant fuelled with coal working under supercritical steam parameters and integrated with a CO 2 capture installation and a gas turbine system. The motivation behind using a gas turbine in the system was to generate steam to supply heat for the stripping process that occurs in the separation installation to regenerate the sorbent. Additional analyses were conducted for the reference case, a CHP unit in which the CO 2 separation process was not conducted, to enable an economic evaluation of the integration of a CHP unit with a CO 2 separation installation according to the variants proposed. The break-even price of electricity and avoided emission costs were used to evaluate the respective solutions. In this paper, the results of the sensitivity analysis of the economic evaluation indicators in terms of the change in the annual operation time, price of emission allowance and heat demand rate for the realization of the stripping process for all cases are presented

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

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

Development of Next Generation micro-CHP System

DEFF Research Database (Denmark)

Arsalis, Alexandros

Novel proposals for the modeling and operation of a micro-CHP (combined-heat-andpower) residential system based on HT-PEMFC (High Temperature-Proton Exchange Membrane Fuel Cell) technology are described and analyzed to investigate the technical feasibility of such systems. The proposed systems must...

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

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.)

A family of serine proteases of Clavibacter michiganensis subsp. michiganensis: chpC plays a role in colonization of the host plant tomato.

Science.gov (United States)

Stork, Ines; Gartemann, Karl-Heinz; Burger, Annette; Eichenlaub, Rudolf

2008-09-01

Genes for seven putative serine proteases (ChpA-ChpG) belonging to the trypsin subfamily and homologous to the virulence factor pat-1 were identified on the chromosome of Clavibacter michiganensis subsp. michiganensis (Cmm) NCPPB382. All proteases have signal peptides indicating export of these proteins. Their putative function is suggested by two motifs and an aspartate residue typical for serine proteases. Furthermore, six cysteine residues are located at conserved positions. The genes are clustered in a chromosomal region of about 50 kb with a significantly lower G + C content than common for Cmm. The genes chpA, chpB and chpD are pseudogenes as they contain frame shifts and/or in-frame stop codons. The genes chpC and chpG were inactivated by the insertion of an antibiotic resistance cassette. The chpG mutant was not impaired in virulence. However, in planta the titre of the chpC mutant was drastically reduced and only weak disease symptoms were observed. Complementation of the chpC mutant by the wild-type allele restored full virulence. ChpC is the first chromosomal gene of Cmm identified so far that affects the interaction of the pathogen with the host plant.

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...

Development of HT-PEMFC components and stack for CHP unit

Energy Technology Data Exchange (ETDEWEB)

Jensen, Jens Oluf; Li, Q. (Technical Univ. of Denmark, Dept. of Chemistry, Kgs. Lyngby (Denmark)); Terkelsen, C.; Rudbech, H.C.; Steenberg, T. (Danish Power System Aps, Charlottenlund (Denmark)); Thibault de Rycke (IRD Fuel Cell A/S, Svendborg (Denmark))

2009-10-15

The aim of the project has been to further develop components for an all Danish high temperature PEM fuel cells stack for application in combined heat and power units (CHP units). The final product aimed at was a 1.5-2 kW stack for operation at 150-200 deg. C. The project follows the previous PSO project 4760, 'High Temperature PEM Fuel Cell'. The project has addressed the HT-PEM fuel cells form a components point of view and the materials here for. The main areas were polymer and membrane development, electrode and MEA development (MEA = membrane electrode assembly, i.e. the cells.) and stack development. The membrane development begins with the polymer. The polymerization technique was improved significantly in two ways. Better understanding of the process and the critical issues has led to more reproducible results with repeated high molecular weights. The molecular weight is decisive for the membrane strength and durability. The process was also scaled up to 100-200 g polymer pr. batch in a new polymerization facility build during the project. It is dimensioned for larger batches too, but this was not verified during the project. The polymer cannot be purchased in the right quality for fuel cell membranes and it is important that it manufacture is not a limiting factor at the present state. Experiments with other membrane casting techniques were also made. The traditional PBI doped with phosphoric acid is still the state of art membrane for the HT-PEM fuel cells, but progress was also made with modified membranes. Different variants of PBI were synthesized and tested. Electrodes have been manufactured by a spray technique in contrast to the previously applied tape casting. The hand held spray gun previously led to an improvement of the electrodes, but the reproducibility was limited. Subsequently the construction of a semi automated spray machine was started and results like of the best hand sprayed electrodes were obtained. A viable way of MEA rim

ChpK and MazF of the toxin-antitoxin modules are involved in the virulence of Leptospira interrogans during infection.

Science.gov (United States)

Komi, Komi Koukoura; Ge, Yu-Mei; Xin, Xiao-Yang; Ojcius, David M; Sun, Dexter; Hu, Wei-Lin; Zhao, Xin; Lin, Xu'ai; Yan, Jie

2015-01-01

Pathogenic Leptospira species are the causative agents of leptospirosis, a global zoonotic infectious disease. Toxin-antitoxin (TA) modules have been confirmed as stress-response elements that induce prokaryotic and eukaryotic cell-growth arrest or death, but their role in the virulence of Leptospira has not been reported. Here, we confirmed that all the tested leptospiral strains had the chpIK and mazEF TA modules with highly-conserved sequences. The transcription and expression of the chpI, chpK, mazE, and mazF genes of Leptospira interrogans strain Lai were significantly increased during infection of phorbol 12-myristate 13-acetate-induced human THP-1 macrophages. The toxic ChpK and MazF but not the antitoxic ChpI and MazE proteins were detectable in the cytoplasmic fraction of leptospire-infected THP-1 cells, indicating the external secretion of ChpK and MazF during infection. Transfection of the chpK or mazF gene caused decreased viability and necrosis in THP-1 cells, whereas the chpI or mazE gene transfection did not affect the viability of THP-1 cells but blocked the ChpK or MazF-induced toxicity. Deletion of the chpK or mazF gene also decreased the late-apoptotic and/or necrotic ratios of THP-1 cells at the late stages of infection. The recombinant protein MazF (rMazF) cleaved the RNAs but not the DNAs from Leptospira and THP-1 cells, and this RNA cleavage was blocked by rMazE. However, the rChpK had no RNA or DNA-degrading activity. All these findings indicate that the ChpK and MazF proteins in TA modules are involved in the virulence of L. interrogans during infection. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Modeling and simulation of a residential micro-CHP system based on HT-PEMFC technology

DEFF Research Database (Denmark)

Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

2009-01-01

Combined-heat-and-power (CHP) technology is a well known and proved method to produce simultaneously power and heat at high efficiencies. This can be further improved by the introduction of a novel micro-CHP residential system based on High Temperature-Proton Exchange Membrane Fuel Cell (HT-PEMFC......). The HT-PEMFC (based on PBI-membrane technology) operates at temperatures near 200oC, and this can be an ideal match for cogeneration residential systems. The proposed system provides electric power, hot water, and space heating for a typical household (1-5 kWe, 5-10 kWth). The micro-CHP system...

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.

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.

A Study of a Diesel Engine Based Micro-CHP System

Energy Technology Data Exchange (ETDEWEB)

Krishna, C.R.; Andrews, J.; Tutu, N.; Butcher, T.

2010-08-31

This project, funded by New York State Energy Research and Development Agency (NYSERDA), investigated the potential for an oil-fired combined heat and power system (micro-CHP system) for potential use in residences that use oil to heat their homes. Obviously, this requires the power source to be one that uses heating oil (diesel). The work consisted of an experimental study using a diesel engine and an analytical study that examined potential energy savings and benefits of micro-CHP systems for 'typical' locations in New York State. A search for a small diesel engine disclosed that no such engines were manufactured in the U.S. A single cylinder engine manufactured in Germany driving an electric generator was purchased for the experimental work. The engine was tested using on-road diesel fuel (15 ppm sulfur), and biodiesel blends. One of the main objectives was to demonstrate the possibility of operation in the so-called HCCI (Homogeneous Charge Compression Ignition) mode. The HCCI mode of operation of engines is being explored as a way to reduce the emission of smoke, and NOx significantly without exhaust treatment. This is being done primarily in the context of engines used in transportation applications. However, it is felt that in a micro-CHP application using a single cylinder engine, such an approach would confer those emission benefits and would be much easier to implement. This was demonstrated successfully by injecting the fuel into the engine air intake using a heated atomizer made by Econox Technologies LLC to promote significant vaporization before entering the cylinder. Efficiency and emission measurements were made under different electrical loads provided by two space heaters connected to the generator in normal and HCCI modes of operation. The goals of the analytical work were to characterize, from the published literature, the prime-movers for micro-CHP applications, quantify parametrically the expected energy savings of using micro-CHP

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.

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.

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.

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)

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.

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

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

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

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.

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)

Reactive power control with CHP plants - A demonstration

DEFF Research Database (Denmark)

Nyeng, Preben; Østergaard, Jacob; Andersen, Claus A.

2010-01-01

power rating of 7.3 MW on two synchronous generators. A closed-loop control is implemented, that remote controls the CHP plant to achieve a certain reactive power flow in a near-by substation. The solution communicates with the grid operator’s existing SCADA system to obtain measurements from...... lines to underground cables has changed the reactive power balance, and third, the TSO has introduced restrictions in the allowed exchange of reactive power between the transmission system and distribution grids (known as the Mvar-arrangement). The demonstration includes a CHP plant with an electric......In this project the potential for ancillary services provision by distributed energy resources is investigated. Specifically, the provision of reactive power control by combined heat and power plants is examined, and the application of the new standard for DER communication systems, IEC 61850...

New CHP plant for a rubber products manufacturer

International Nuclear Information System (INIS)

Vila, R.; Martí, C.

2016-01-01

At the end of 2014 the company Industrias de Hule Galgo decided to undertake the installation project of an efficient CHP plant for its production plant, with the aim of bringing down energy costs and improving the company’s competitive position in the market. The new plant has already started its first operational phase. The project has comprised the installation of a single cycle with gas-powered gensets providing a total electrical capacity of 6.6 MW. This provides the necessary thermal oil for the production plant; covers 100% of the electrical power consumed by the industrial complex; and also generates cooling water, giving improved production capacity by supercooling the extrusion system. To execute these works, Industrias de Hule Galgo contracted the services of engineering company AESA to provide the engineering, procurement and construction of the CHP plant. (Author)

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.

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.

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.

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.

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.

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.

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.

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.

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

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

Science.gov (United States)

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

2008-01-01

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

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.

The Pseudomonas aeruginosa Chp Chemosensory System Regulates Intracellular cAMP Levels by Modulating Adenylate Cyclase Activity

Science.gov (United States)

Fulcher, Nanette B.; Holliday, Phillip M.; Klem, Erich; Cann, Martin J.; Wolfgang, Matthew C.

2010-01-01

Summary Multiple virulence systems in the opportunistic pathogen Pseudomonas aeruginosa are regulated by the second messenger signaling molecule adenosine 3’, 5’-cyclic monophosphate (cAMP). Production of cAMP by the putative adenylate cyclase enzyme CyaB represents a critical control point for virulence gene regulation. To identify regulators of CyaB, we screened a transposon insertion library for mutants with reduced intracellular cAMP. The majority of insertions resulting in reduced cAMP mapped to the Chp gene cluster encoding a putative chemotaxis-like chemosensory system. Further genetic analysis of the Chp system revealed that it has both positive and negative effects on intracellular cAMP and that it regulates cAMP levels by modulating CyaB activity. The Chp system was previously implicated in the production and function of type IV pili (TFP). Given that cAMP and the cAMP-dependent transcriptional regulator Vfr control TFP biogenesis gene expression, we explored the relationship between cAMP, the Chp system and TFP regulation. We discovered that the Chp system controls TFP production through modulation of cAMP while control of TFP-dependent twitching motility is cAMP-independent. Overall, our data define a novel function for a chemotaxis-like system in controlling cAMP production and establish a regulatory link between the Chp system, TFP and other cAMP-dependent virulence systems. PMID:20345659

Changes of the thermodynamic parameters in failure conditions of the micro-CHP cycle

Science.gov (United States)

Matysko, Robert; Mikielewicz, Jarosław; Ihnatowicz, Eugeniusz

2014-03-01

The paper presents the calculations for the failure conditions of the ORC (organic Rankine cycle) cycle in the electrical power system. It analyses the possible reasons of breakdown, such as the electrical power loss or the automatic safety valve failure. The micro-CHP (combined heat and power) system should have maintenance-free configuration, which means that the user does not have to be acquainted with all the details of the ORC system operation. However, the system should always be equipped with the safety control systems allowing for the immediate turn off of the ORC cycle in case of any failure. In case of emergency, the control system should take over the safety tasks and protect the micro-CHP system from damaging. Although, the control systems are able to respond quickly to the CHP system equipped with the inertial systems, the negative effects of failure are unavoidable and always remain for some time. Moreover, the paper presents the results of calculations determining the inertia for the micro-CHP system of the circulating ORC pump, heat removal pump (cooling condenser) and the heat supply pump in failure conditions.

Changes of the thermodynamic parameters in failure conditions of the micro-CHP cycle

Directory of Open Access Journals (Sweden)

Matysko Robert

2014-03-01

Full Text Available The paper presents the calculations for the failure conditions of the ORC (organic Rankine cycle cycle in the electrical power system. It analyses the possible reasons of breakdown, such as the electrical power loss or the automatic safety valve failure. The micro-CHP (combined heat and power system should have maintenance-free configuration, which means that the user does not have to be acquainted with all the details of the ORC system operation. However, the system should always be equipped with the safety control systems allowing for the immediate turn off of the ORC cycle in case of any failure. In case of emergency, the control system should take over the safety tasks and protect the micro-CHP system from damaging. Although, the control systems are able to respond quickly to the CHP system equipped with the inertial systems, the negative effects of failure are unavoidable and always remain for some time. Moreover, the paper presents the results of calculations determining the inertia for the micro-CHP system of the circulating ORC pump, heat removal pump (cooling condenser and the heat supply pump in failure conditions.

Utilization of straw in district heating and CHP plants

International Nuclear Information System (INIS)

Nikolaisen, L.

1993-01-01

In Denmark 64 straw-fired district heating plants and 6 decentral CHP plants have been built since 1980 which are completely or partly straw-fired. The annual straw consumption in the district heating plants is 275,000 tons and in the decentral plants about 200,000 tons. The size of the district heating plants amounts to 0.5 MW - 10 MW and that of the CHP plants to 7 MW - 67 MW heat flow rate. Either whole bales or cut/scarified straw is used for firing. Hesston bales of about 450 kg control the market. The Centre of Biomass Technology is an activity supported 100 % by the Danish Energy Agency with the purpose of increasing the use of straw and wood in the energy supply (orig.)

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.

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.

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.

Environmental sustainability analysis of UK whole-wheat bioethanol and CHP systems

International Nuclear Information System (INIS)

Martinez-Hernandez, Elias; Ibrahim, Muhammad H.; Leach, Matthew; Sinclair, Phillip; Campbell, Grant M.; Sadhukhan, Jhuma

2013-01-01

The UK whole-wheat bioethanol and straw and DDGS-based combined heat and power (CHP) generation systems were assessed for environmental sustainability using a range of impact categories or characterisations (IC): cumulative primary fossil energy (CPE), land use, life cycle global warming potential over 100 years (GWP 100 ), acidification potential (AP), eutrophication potential (EP) and abiotic resources use (ARU). The European Union (EU) Renewable Energy Directive's target of greenhouse gas (GHG) emission saving of 60% in comparison to an equivalent fossil-based system by 2020 seems to be very challenging for stand-alone wheat bioethanol system. However, the whole-wheat integrated system, wherein the CHP from the excess straw grown in the same season and from the same land is utilised in the wheat bioethanol plant, can be demonstrated for potential sustainability improvement, achieving 85% emission reduction and 97% CPE saving compared to reference fossil systems. The net bioenergy from this system and from 172,370 ha of grade 3 land is 12.1 PJ y −1 providing land to energy yield of 70 GJ ha −1 y −1 . The use of DDGS as an animal feed replacing soy meal incurs environmental emission credit, whilst its use in heat or CHP generation saves CPE. The hot spots in whole system identified under each impact category are as follows: bioethanol plant and wheat cultivation for CPE (50% and 48%), as well as for ARU (46% and 52%). EP and GWP 100 are distributed among wheat cultivation (49% and 37%), CHP plant (26% and 30%) and bioethanol plant (25%, and 33%), respectively. -- Highlights: ► UK whole-wheat energy system can achieve 85% GHG emission reduction. ► UK whole-wheat energy system can achieve 97% primary energy saving. ► The land to energy yield of the UK whole-wheat system is 70 GJ ha −1 y −1 . ► Fertiliser production is the hotspot. ► DDGS and straw-based CHP system integration to wheat bioethanol is feasible

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

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.)

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.

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.

Optimisation of Combined Cycle Gas Turbine Power Plant in Intraday Market: Riga CHP-2 Example

Science.gov (United States)

Ivanova, P.; Grebesh, E.; Linkevics, O.

2018-02-01

In the research, the influence of optimised combined cycle gas turbine unit - according to the previously developed EM & OM approach with its use in the intraday market - is evaluated on the generation portfolio. It consists of the two combined cycle gas turbine units. The introduced evaluation algorithm saves the power and heat balance before and after the performance of EM & OM approach by making changes in the generation profile of units. The aim of this algorithm is profit maximisation of the generation portfolio. The evaluation algorithm is implemented in multi-paradigm numerical computing environment MATLab on the example of Riga CHP-2. The results show that the use of EM & OM approach in the intraday market can be profitable or unprofitable. It depends on the initial state of generation units in the intraday market and on the content of the generation portfolio.

CHP expansion strategy in North Rhine-Westphalia. A blueprint for other regions; KWK-Ausbaustrategie in NRW. Eine Blaupause fuer andere Regionen

Energy Technology Data Exchange (ETDEWEB)

Holzapfel, Dominik [EnergieAgentur.NRW, Duesseldorf (Germany); Schneider, Sabine [EnergieAgentur.NRW, Wuppertal (Germany)

2015-10-01

The North Rhine-Westphalian state government intends to increase the share of combined heat and power (CHP) generation to at least 25 % by 2020. Since 2013, the campaign ''CHP.NRW - Power Meets Heat'' (''KWK.NRW - Strom trifft Waerme'') of the EnergyAgency.NRW, is has been running on behalf of the NRW Climate Protection Ministry, to publicise this technology and to promote its expansion. The campaign accompanies the State Government's CHP Stimulus Programme. The EnergyAgency.NRW has organised companies and research institutions, associations and interest groups under the umbrella of ''CHP.NRW - Power Meets Heat'', aiming at co-ordinated and intensified activities in the field of combined heat and power generation. The target of the initial-project ''roadmap/CHP.NRW'' of the ''Virtual Institute / CHP.NRW'' is to develop a guideline for the application and optimisation of CHP-systems.

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

International Nuclear Information System (INIS)

Bents, D.J.

1991-01-01

Free Piston Stirling Engine (FPSE) and linear alternator (LA) technology is combined with radioisotope heat sources to produce a compact dynamic isotope power system (DIPS) suitable for multihundred watt space application which appears competitive with advance radioisotope thermoelectric generators (RTGs). The small Stirling DIPS is scalable to multihundred watt power levels or lower. The FPSE/LA is a high efficiency convertor in sizes ranging from tens of kilowatts down to only a few watts. At multihundred watt unit size, the FPSE can be directly integrated with the General Purpose Heat Source (GPHS) via radiative coupling; the resulting dynamic isotope power system has a size and weight that compares favorably with the advanced modular (Mod) RTG, but requires less than a third the amount of isotope fuel. Thus the FPSE extends the high efficiency advantage of dynamic systems into a power range never previously considered competitive for DIPS. This results in lower fuel cost and reduced radiological hazard per delivered electrical watt. 33 refs

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.

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.

Ecological assessment of new CHP systems and their combination; Oekologische Bewertung neuer WKK-Systeme und Systemkombinationen - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Primas, A.

2007-07-01

This final report for the Swiss Federal Office of Energy (SFOE) reports on new developments in the Combined Heat and Power (CHP) generation area. The objective of this study is an ecological and technical evaluation of various CHP systems and system combinations. These also include suitable combinations with other technologies. Systems for five different temperature levels are quantified according to their environmental impact. Various possible applications are compared with a highly efficient reference system using separate heat and power generation - a combined-cycle plant and a heat pump. For chilled water production a combination of the CHP system with an absorption chiller is investigated. The results of the investigations are presented and commented on. Also, advantageous applications of CHP systems are noted.

Micro scale CHP based on biomass intelligent heat transfer with thermoelectric generators

Energy Technology Data Exchange (ETDEWEB)

Moser, W.; Aigenbauer, S.; Heckmann, M.; Friedl, G. (Austrian Bioenergy Centre GmbH, Wieselburg (Austria)); Hofbauer, H. (Institute of Chemical Engineering, Vienna University of Technology (Austria))

2007-07-01

Pellet burners need auxiliary electrical power to provide CO{sub 2} balanced heat in a comfortable and environment friendly way. The idea is to produce this and some extra electricity within the device in order to save resources and to gain operation reliability and independency. An option for micro scale CHP is the usage of thermoelectric generators (TEGs). They allow direct conversion of heat into electrical power. They have the advantage of a long maintenance free durability and noiseless operation without moving parts or any working fluid. The useful heat remains almost unaffected and can still be used for heating. TEGs are predestined for the use in micro scale CHP based on solid biomass. In this paper the first results from the fully integrated prototype are presented. The performance of the TEG was observed for different loads and operating conditions in order to realise an optimised micro scale CHP based on solid biomass. (orig.)

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

Science.gov (United States)

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

2015-01-01

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

Research, Development and Demonstration of Micro-CHP System for Residential Applications

Energy Technology Data Exchange (ETDEWEB)

Karl Mayer

2010-03-31

ECR International and its joint venture company, Climate Energy, are at the forefront of the effort to deliver residential-scale combined heat and power (Micro-CHP) products to the USA market. Part of this substantial program is focused on the development of a new class of steam expanders that offers the potential for significantly lower costs for small-scale power generation technology. The heart of this technology is the scroll expander, a machine that has revolutionized the HVAC refrigerant compressor industry in the last 15 years. The liquid injected cogeneration (LIC) technology is at the core of the efforts described in this report, and remains an excellent option for low cost Micro-CHP systems. ECR has demonstrated in several prototype appliances that the concept for LIC can be made into a practical product. The continuing challenge is to identify economical scroll machine designs that will meet the performance and endurance requirements needed for a long life appliance application. This report describes the numerous advances made in this endeavor by ECR International. Several important advances are described in this report. Section 4 describes a marketing and economics study that integrates the technical performance of the LIC system with real-world climatic data and economic analysis to assess the practical impact that different factors have on the economic application of Micro-CHP in residential applications. Advances in the development of a working scroll steam expander are discussed in Section 5. A rigorous analytical assessment of the performance of scroll expanders, including the difficult to characterize impact of pocket to pocket flank leakage, is presented in Section 5.1. This is followed with an FEA study of the thermal and pressure induced deflections that would result from the normal operation of an advanced scroll expander. Section 6 describes the different scroll expanders and test fixtures developed during this effort. Another key technical

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

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

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.

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.

Simulation of energy use in buildings with multiple micro generators

International Nuclear Information System (INIS)

Karmacharya, S.; Putrus, G.; Underwood, C.P.; Mahkamov, K.; McDonald, S.; Alexakis, A.

2014-01-01

This paper focuses on the detailed modelling of micro combined heat and power (mCHP) modules and their interaction with other renewable micro generators in domestic applications based on an integrated modular modelling approach. The simulation model has been developed using Matlab/Simulink and incorporates a Stirling engine mCHP module embedded in a lumped-parameter domestic energy model, together with contributions from micro wind and photovoltaic modules. The Stirling cycle component model is based on experimental identification of a domestic-scale system which includes start up and shut down characteristics. The integrated model is used to explore the interactions between the various energy supply technologies and results are presented showing the most favourable operating conditions that can be used to inform the design of advanced energy control strategies in building. The integrated model offers an improvement on previous models of this kind in that a fully-dynamic approach is adopted for the equipment and plant enabling fast changing load events such as switching on/off domestic loads and hot water, to be accurately captured at a minimum interval of 1 min. The model is applied to two typical 3- and 4-bedroom UK house types equipped with a mCHP module and two other renewable energy technologies for a whole year. Results of the two cases show that the electrical contribution of a Stirling engine type mCHP heavily depends on the thermal demand of the building and that up to 19% of the locally-generated electricity is exported whilst meeting a similar percentage of the overall annual electricity demand. Results also show that the increased number of switching of mCHP module has an impact on seasonal module efficiency and overall fuel utilisation. The results demonstrate the need for the analysis of equipment design and optimal sizing of thermal and electrical energy storage. -- Highlights: • Dynamic modelling of a building along with its space heating and hot

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

Optimal designs of small CHP plants in a market with fluctuating electricity prices

DEFF Research Database (Denmark)

Lund, Henrik; Andersen, A.N.

2005-01-01

The paper presents the Danish experince with methodologies and software tools, which have been used to design investment and operation strategies for almost all small CHP plants in Denmark during the decade of the triple tariff.......The paper presents the Danish experince with methodologies and software tools, which have been used to design investment and operation strategies for almost all small CHP plants in Denmark during the decade of the triple tariff....

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.

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.

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

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

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

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

Optimisation of Combined Cycle Gas Turbine Power Plant in Intraday Market: Riga CHP-2 Example

Directory of Open Access Journals (Sweden)

Ivanova P.

2018-02-01

Full Text Available In the research, the influence of optimised combined cycle gas turbine unit – according to the previously developed EM & OM approach with its use in the intraday market – is evaluated on the generation portfolio. It consists of the two combined cycle gas turbine units. The introduced evaluation algorithm saves the power and heat balance before and after the performance of EM & OM approach by making changes in the generation profile of units. The aim of this algorithm is profit maximisation of the generation portfolio. The evaluation algorithm is implemented in multi-paradigm numerical computing environment MATLab on the example of Riga CHP-2. The results show that the use of EM & OM approach in the intraday market can be profitable or unprofitable. It depends on the initial state of generation units in the intraday market and on the content of the generation portfolio.

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.

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)

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

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.

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

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.

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

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

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.

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

Hybrid Solid Oxide Fuel Cell and Thermoelectric Generator for Maximum Power Output in Micro-CHP Systems

DEFF Research Database (Denmark)

Rosendahl, Lasse; Mortensen, Paw Vestergård; Enkeshafi, Ali A.

2011-01-01

and market segments which are not yet quantified. This paper quantifies a micro-CHP system based on a solid oxide fuel cell (SOFC) and a high-performance TE generator. Based on a 3 kW fuel input, the hybrid SOFC implementation boosts electrical output from 945 W to 1085 W, with 1794 W available for heating...... the electricity production in micro-CHP systems by more than 15%, corresponding to system electrical efficiency increases of some 4 to 5 percentage points. This will make fuel cell-based micro-CHP systems very competitive and profitable and will also open opportunities in a number of other potential business...

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.

Potential for CHP in Africa

International Nuclear Information System (INIS)

Yameogo, Gabriel

2000-01-01

It is suggested that many industries in Africa could benefit from biomass-fired cogeneration so long as the correct structures and learning processes are put in place. The article discusses Africa's energy background and gives figures for generation sources and consumption. A profile of Sudan and its energy needs is presented. It is argued that although some barriers do exist, a move to cogeneration is essential. CHP should be particularly attractive for industries able to use thermal energy for drying, heating and cooling: typical areas would be pharmaceutical and chemical plants, textile factories, cement works and steel mills

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

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

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.

New power packs; Neue Kraftpakete

Energy Technology Data Exchange (ETDEWEB)

Lennartz, Marc Wilhelm

2013-11-15

In this article reports about CHP's that work with wood as an energy source. Thus, for example the Austrian company Button Energy has developed a micro-CHP unit that produces electricity by steam. In this Bison PowerBlock works a pellet boiler with control, producing wood gas and mixed with secondary air. The company Oekofen with their Pellematic Smart-E is using a modified pellet stove with integrated buffer storage plus Stirling engine, which is responsible for the generation of electricity. The Lower Bavarian company Spanner Re GmbH produces CHP operated by wood chips. [German] In diesem Artikel wird ueber Blockheizkraftwerke (BHKW) berichtet, die mit Holz als Energiequelle arbeiten. So hat z.B. die oesterreichische Firma Button Energy hat ein Mikro-BHKW entwickelt, das Strom mittels Wasserdampf produziert. In diesem Bison Powerblock arbeitet ein Pelletkessel mit Regelung, der Holzgas erzeugt und dieses mit Sekundaerluft mischt. Die Firma Oekofen setzt bei ihrem Pellematic Smart-E auf einen modifizierten Pelletofen mit integriertem Pufferspeicher plus Stirlingmotor, der fuer die Stromerzeugung verantwortlich ist. Das niederbayrische Unternehmen Spanner Re GmbH produziert BHKW, die mit Hackschnitzeln betrieben werden.

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.

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.

IEA Energy Technology Essentials: Biomass for Power Generation and CHP

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-01-15

The IEA Energy Technology Essentials series offers concise four-page updates on the different technologies for producing, transporting and using energy. Biomass for Power Generation and CHP is the topic covered in this edition.

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.

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.

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.

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.

Evaluation of Combined Heat and Power (CHP Systems Using Fuzzy Shannon Entropy and Fuzzy TOPSIS

Directory of Open Access Journals (Sweden)

Fausto Cavallaro

2016-06-01

Full Text Available Combined heat and power (CHP or cogeneration can play a strategic role in addressing environmental issues and climate change. CHP systems require less fuel than separate heat and power systems in order to produce the same amount of energy saving primary energy, improving the security of the supply. Because less fuel is combusted, greenhouse gas emissions and other air pollutants are reduced. If we are to consider the CHP system as “sustainable”, we must include in its assessment not only energetic performance but also environmental and economic aspects, presenting a multicriteria issue. The purpose of the paper is to apply a fuzzy multicriteria methodology to the assessment of five CHP commercial technologies. Specifically, the combination of the fuzzy Shannon’s entropy and the fuzzy Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS approach will be tested for this purpose. Shannon’s entropy concept, using interval data such as the α-cut, is a particularly suitable technique for assigning weights to criteria—it does not require a decision-making (DM to assign a weight to the criteria. To rank the proposed alternatives, a fuzzy TOPSIS method has been applied. It is based on the principle that the chosen alternative should be as close as possible to the positive ideal solution and be as far as possible from the negative ideal solution. The proposed approach provides a useful technical–scientific decision-making tool that can effectively support, in a consistent and transparent way, the assessment of various CHP technologies from a sustainable point of view.

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.

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.

Validation of a HT-PEMFC stack for CHP applications

Energy Technology Data Exchange (ETDEWEB)

Pasupathi, S.; Ulleberg, Oe. [Western Cape Univ. (South Africa). HySA Systems, SAIAMC; Bujlo, P. [Western Cape Univ. (South Africa). HySA Systems, SAIAMC; Electrotechnical Institute Wroclaw Division (Poland); Scholta, J. [Centre for Solar Energy and Hydrogen Research (ZSW) (Germany)

2010-07-01

Fuel cell systems are very attractive for stationary co-generation applications as they can produce heat and electricity efficiently in a decentralized and environmentally friendly manner. PEMFC stacks operating at temperatures above 120 C, specifically in the range of 140-180 C, are ideal for co-generation purposes. In this study, preliminary results from a HTPEMFC stack designed for CHP applications is presented and discussed. A short, five-cell, HT-PEMFC stack was assembled with Celtec- P-2100 MEAs and validated in terms of electrical performance. The stack was operated with hydrogen and air at 160 C and the utilization curves for anode and cathode were recorded for a wide range of gas utilization at a current density of 0.52 A/cm{sup 2}. The current voltage characteristic was measured at optimal utilization values at 160 C. A 1kW stack is assembled and is currently being validated for its performance under various operating conditions for use in CHP applications. (orig.)

Sizing Combined Heat and Power Units and Domestic Building Energy Cost Optimisation

Directory of Open Access Journals (Sweden)

Dongmin Yu

2017-06-01

Full Text Available Many combined heat and power (CHP units have been installed in domestic buildings to increase energy efficiency and reduce energy costs. However, inappropriate sizing of a CHP may actually increase energy costs and reduce energy efficiency. Moreover, the high manufacturing cost of batteries makes batteries less affordable. Therefore, this paper will attempt to size the capacity of CHP and optimise daily energy costs for a domestic building with only CHP installed. In this paper, electricity and heat loads are firstly used as sizing criteria in finding the best capacities of different types of CHP with the help of the maximum rectangle (MR method. Subsequently, the genetic algorithm (GA will be used to optimise the daily energy costs of the different cases. Then, heat and electricity loads are jointly considered for sizing different types of CHP and for optimising the daily energy costs through the GA method. The optimisation results show that the GA sizing method gives a higher average daily energy cost saving, which is 13% reduction compared to a building without installing CHP. However, to achieve this, there will be about 3% energy efficiency reduction and 7% input power to rated power ratio reduction compared to using the MR method and heat demand in sizing CHP.

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.

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.

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.

The Comparison of Photovoltaic with Small Solar Dish Stirling for Solar Home System 50 W{sub p} in Thailand, Medium Insolation Nature

Energy Technology Data Exchange (ETDEWEB)

Snidvongs, E. S.; Jindaruj, S.

2006-07-01

The Thai government initiated a project entitled Solar Home System which involved the provision of standalone Photovoltaic 50 Wp for houses without transmission lines in remote areas, 300,000 units. These units are provided at a low price with the government supporting half of the cost and the rest paid by the owners in installments. So far, more than 150,000 units have been installed and it is expected that the whole project would be completed by the end of the year 2005. A purpose of this research is to compare the original Thai government's Solar Home PV System with the new 50 Wp Small Solar Thermal Dish Stirling System in terms of their advantages and disadvantages for Thailand. The result of this would serve as a guide for the users to select the most suitable system in terms of price, maintenance, cost, economy, performance, reliability, and efficiency. Such comparison will be presented in the form of descriptive, photographs, statistics, and tables. As for the data involved, part of this is based on active fact such as construction cost, material cost, labor cost, rate of inflation, rate of interest. While some of these derives from the experience of researcher as well as facts and figures from Thai governments publications such as operation and maintenance cost. In addition to that some data are taken from basic experiments conducted either by the various universities and the researcher own laboratory. These include solar insolation, PV data and Stirling engine test with electric heater. And, of course, some data are based on simple estimation and prediction. Thailand is a country of 550 w/m2 with high humidity, soft-land and medium insolation. It locates near the equator at latitude 5 12 N, longitude 96 106 E. By using a parabolic shape satellite dish with solar tracker and a 60 W Four Cylinders gamma type Stirling engine with sinusoidal gear linear link, low offset space, and solid thermal storage to act as buffer between the solar energy and the

Anti-diabetic effect of Cyclo-His-Pro (CHP)-enriched yeast ...

African Journals Online (AJOL)

Anti-diabetic effect of Cyclo-His-Pro (CHP)-enriched yeast hydrolysate in ... The present study was designed to investigate the hypoglycemic effects of the daily ... in the area under curve (AUC) value of YH supplemented groups as compared ...

CHP Integrated with Burners for Packaged Boilers

Energy Technology Data Exchange (ETDEWEB)

Castaldini, Carlo; Darby, Eric

2013-09-30

The objective of this project was to engineer, design, fabricate, and field demonstrate a Boiler Burner Energy System Technology (BBEST) that integrates a low-cost, clean burning, gas-fired simple-cycle (unrecuperated) 100 kWe (net) microturbine (SCMT) with a new ultra low-NOx gas-fired burner (ULNB) into one compact Combined Heat and Power (CHP) product that can be retrofit on new and existing industrial and commercial boilers in place of conventional burners. The Scope of Work for this project was segmented into two principal phases: (Phase I) Hardware development, assembly and pre-test and (Phase II) Field installation and demonstration testing. Phase I was divided into five technical tasks (Task 2 to 6). These tasks covered the engineering, design, fabrication, testing and optimization of each key component of the CHP system principally, ULNB, SCMT, assembly BBEST CHP package, and integrated controls. Phase I work culminated with the laboratory testing of the completed BBEST assembly prior to shipment for field installation and demonstration. Phase II consisted of two remaining technical tasks (Task 7 and 8), which focused on the installation, startup, and field verification tests at a pre-selected industrial plant to document performance and attainment of all project objectives. Technical direction and administration was under the management of CMCE, Inc. Altex Technologies Corporation lead the design, assembly and testing of the system. Field demonstration was supported by Leva Energy, the commercialization firm founded by executives at CMCE and Altex. Leva Energy has applied for patent protection on the BBEST process under the trade name of Power Burner and holds the license for the burner currently used in the product. The commercial term Power Burner is used throughout this report to refer to the BBEST technology proposed for this project. The project was co-funded by the California Energy Commission and the Southern California Gas Company (SCG), a

IVO`s CHP know-how: experience, inventions, patents

Energy Technology Data Exchange (ETDEWEB)

Aeijaelae, M.; Ohtonen, V. [ed.

1997-11-01

IVO can justly claim mastery in the co-generation of district heat and electricity - CHP. As well as looking at the issue from the viewpoint of planners, builders and operators, IVO`s engineers also view power plants through the eyes of the product developer and inventor. This approach has resulted in successful power plant configurations, inventions and patents and visions

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

Performance and cost results from a DOE Micro-CHP demonstration facility at Mississippi State University

International Nuclear Information System (INIS)

Giffin, Paxton K.

2013-01-01

Highlights: ► We examine the cost and performance results of a Micro-CHP demonstration facility. ► Evaluation includes both summer and winter performance. ► Evaluation in comparison to a conventional HVAC system using grid power. ► Influence of improperly sized equipment. ► Influence of natural gas prices on the viability of CHP projects using that fuel. - Abstract: Cooling, Heating, and Power (CHP) systems have been around for decades, but systems that utilize 20 kW or less, designated as Micro-CHP, are relatively new. A demonstration site has been constructed at Mississippi State University (MSU) to show the advantages of these micro scale systems. This study is designed to evaluate the performance of a Micro-CHP system as opposed to a conventional high-efficiency Heating, Ventilation, and Air Conditioning (HVAC) system that utilizes electrical power from the existing power grid. Raw data was collected for 7 months to present the following results. The combined cycle efficiency from the demonstration site was averaged at 29%. The average combined boiler and engine cost was $1.8 h −1 of operation for heating season and $3.9 h −1 of operation for cooling season. The cooling technology used, an absorption chiller exhibited an average Coefficient of Performance (COP) of 0.27. The conventional high-efficiency system, during cooling season, had a COP of 4.7 with a combined cooling and building cost of $0.2 h −1 of operation. During heating mode, the conventional system had an efficiency of 47% with a fuel and building electrical cost of $0.28 h −1 of operation.

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.

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

Characterization of ultrafine and fine particles from CHP Plants

Energy Technology Data Exchange (ETDEWEB)

2009-08-15

Samples of particles collected at CHP plants in the project 'Survey of emissions from CHP Plants' have been analysed in this project to give information on the morphology and chemical composition of individual particle size classes. The objective of this project was to characterize ultrafine and fine particles emitted to the atmosphere from Danish CHP plants. Nine CHP plants were selected in the Emission Survey Project as being representative for the different types of CHP plants operating in Denmark: 1) Three Waste-to Energy (WTE) plants. 2) Three biomass fired (BM) plants (two straw fired, one wood/saw dust fired). 3) Two gas fired (GF) plants (one natural gas, one landfill gas fired). 4) One gasoil (GO) fired plant. At the WTE and BM plants, various types of emission control systems implemented. The results from these plants represent the composition and size distribution of combustion particles that are emitted from the plants emission control systems. The measured emissions of particles from the waste-to-energy plants WTE1-3 are generally very low. The number and mass concentrations of ultrafine particles (PM{sub 0.1}) were particularly low in the flue gas from WTE2 and WTE3, where bag filters are used for the reduction of particle emissions. The EDX analysis of particles from the WTE plants indicates that the PM{sub 0.1} that penetrates the ECS at WTE can contain high fractions of metals such as Fe, Mn and Cu. The SEM analysis of particles from WTE1-3 showed that the particles were generally porous and irregular in shape. The concentrations of particles in the flue gas from the biomass plants were generally higher than found for the WTE plants. The time series results showed that periodical, high concentration peaks of PM emissions occur from BM1 and BM2. The chemical composition of the particles emitted from the three biomass plants is generally dominated by C, O and S, and to some extend also Fe and Si. A high amount of Cu was found in selected

Biomass Power Generation through Direct Integration of Updraft Gasifier and Stirling Engine Combustion System

Directory of Open Access Journals (Sweden)

Jai-Houng Leu

2010-01-01

Full Text Available Biomass is the largest renewable energy source in the world. Its importance grows gradually in the future energy market. Since most biomass sources are low in energy density and are widespread in space, small-scale biomass conversion system is therefore more competitive than a large stand-alone conversion plant. The current study proposes a small-scale solid biomass power system to explore the viability of direct coupling of an updraft fixed bed gasifier with a Stirling engine. The modified updraft fixed bed gasifier employs an embedded combustor inside the gasifier to fully combust the synthetic gas generated by the gasifier. The flue gas produced by the synthetic gas combustion inside the combustion tube is piped directly to the heater head of the Stirling engine. The engine will then extract and convert the heat contained in the flue gas into electricity automatically. Output depends on heat input. And, the heat input is proportional to the flow rate and temperature of the flue gas. The preliminary study of the proposed direct coupling of an updraft gasifier with a 25 kW Stirling engine demonstrates that full power output could be produced by the current system. It could be found from the current investigation that no auxiliary fuel is required to operate the current system smoothly. The proposed technology and units could be considered as a viable solid biomass power system.

EPA's Air Quality Rules for Reciprocating Internal Combustion Engines (RICE) and their Application to CHP (Webinar) – June 24, 2014

Science.gov (United States)

This webinar discusses the effect of EPA's air quality regulations on CHP facilities and stationary RICE, and describes how CHP systems can comply with air quality regulations by using stationary RICE.

Solar parabolic dish Stirling engine system design, simulation, and thermal analysis

International Nuclear Information System (INIS)

Hafez, A.Z.; Soliman, Ahmed; El-Metwally, K.A.; Ismail, I.M.

2016-01-01

Highlights: • Modeling and simulation for different parabolic dish Stirling engine designs using Matlab®. • The effect of solar dish design features and factors had been taken. • Estimation of output power from the solar dish using Matlab®. • The present analysis provides a theoretical guidance for designing and operating solar parabolic dish system. - Abstract: Modeling and simulation for different parabolic dish Stirling engine designs have been carried out using Matlab®. The effect of solar dish design features and factors such as material of the reflector concentrators, the shape of the reflector concentrators and the receiver, solar radiation at the concentrator, diameter of the parabolic dish concentrator, sizing the aperture area of concentrator, focal Length of the parabolic dish, the focal point diameter, sizing the aperture area of receiver, geometric concentration ratio, and rim angle have been studied. The study provides a theoretical guidance for designing and operating solar parabolic dish Stirling engines system. At Zewail city of Science and Technology, Egypt, for a 10 kW Stirling engine; The maximum solar dish Stirling engine output power estimation is 9707 W at 12:00 PM where the maximum beam solar radiation applied in solar dish concentrator is 990 W/m"2 at 12:00 PM. The performance of engine can be improved by increasing the precision of the engine parts and the heat source efficiency. The engine performance could be further increased if a better receiver working fluid is used. We can conclude that where the best time for heating the fluid and fasting the processing, the time required to heat the receiver to reach the minimum temperature for operating the Solar-powered Stirling engine for different heat transfer fluids; this will lead to more economic solar dish systems. Power output of the solar dish system is one of the most important targets in the design that show effectiveness of the system, and this has achieved when we take

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.

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.

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.

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.

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.

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.

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.

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

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

Survey of controllability in decentralized CHP plants. Optimal operation of priority production units; Kortlaegning af decentrale kraftvarmevaerkers regulerbarhed. Optimal drift af prioriterede anlaeg - Teknologisk grundlag

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-03-15

The present report presents results from two closely related projects, carried out in parallel, under the PSO-F and U 2002. The one project is 'Survey of controllability in de-centralized combined heat and power plants' project number PSO 4724 and is fully reported here. The other project: 'Optimal operation of priority production units, project number PSO 4712, only the part project 'Technological foundations is reported here. In project 4724 the technical conditions that matter regarding controllability of electricity production in de-centralized heat and power stations are surveyed. In this context the term controllability means how fast and to which extent the load factors of the plants can be changed. Also, is has been investigated which options are available for improving the controllability, their potentials and estimates on required investments associated. The investigation covers CHP plants having a production capacity of up to 30 MW of electricity. The main part of the de-centralized CHP plants are based on spark ignited internal combustion engines (Otto engines). Most of these engines are fuelled by natural gas and a smaller part by biogas. A minor number are gas turbines fuelled by natural gas and steam turbines in industrial applications, waste incineration plants or in combined cycle power plants. The mapping has among others consisted of a number of visits on selected different types of plants including interview with people responsible for the daily operation. From these interviews data on the actual operating strategy and technical data have been provided. In addition suppliers of engines and other equipment involved have been contacted for technical information or recommendations regarding possible changes in operation strategy. Searching the Internet has been widely used for identification of technical investigations concerning e.g. operation and maintenance of relevant equipment. Finally, substantial statistical data from

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.

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...

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.

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)

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

Optimal design of integrated CHP systems for housing complexes

International Nuclear Information System (INIS)

Fuentes-Cortés, Luis Fabián; Ponce-Ortega, José María; Nápoles-Rivera, Fabricio; Serna-González, Medardo; El-Halwagi, Mahmoud M.

2015-01-01

Highlights: • An optimization formulation for designing domestic CHP systems is presented. • The operating scheme, prime mover and thermal storage system are optimized. • Weather conditions and behavior demands are considered. • Simultaneously economic and environmental objectives are considered. • Two case studies from Mexico are presented. - Abstract: This paper presents a multi-objective optimization approach for designing residential cogeneration systems based on a new superstructure that allows satisfying the demands of hot water and electricity at the minimum cost and the minimum environmental impact. The optimization involves the selection of technologies, size of required units and operating modes of equipment. Two residential complexes in different cities of the State of Michoacán in Mexico were considered as case studies. One is located on the west coast and the other one is in the mountainous area. The results show that the implementation of the proposed optimization method yields significant economic and environmental benefits due to the simultaneous reduction in the total annual cost and overall greenhouse gas emissions

Distributed Control in a Network of Households with microCHP

NARCIS (Netherlands)

Larsen, Gunn; Scherpen, Jacquelien M.A.; van Foreest, Nicolaas

2011-01-01

This is an application of a dynamic price mechanism to distributed optimization of a network of houses which are both producers and consumers of electricity. One possibility for domestic generation is the Micro Combined Heat Power system (µCHP). We use a pricing mechanism based on dual

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.

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.

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.

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.

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

A transient one-dimensional numerical model for kinetic Stirling engine

International Nuclear Information System (INIS)

Wang, Kai; Dubey, Swapnil; Choo, Fook Hoong; Duan, Fei

2016-01-01

Highlights: • A non-equilibrium thermal mode with considering loses is adopted in Stirling engine. • Good agreements are achieved for predicting various critical system parameters. • Differences between helium and hydrogen systems are highlighted and analyzed. • Pressure drop of helium system is much larger and more sensitive to frequency. - Abstract: A third-order numerical model based on one-dimensional computational fluid dynamics is developed for kinetic Stirling engines. Various loss mechanisms in Stirling engines, including gas spring hysteresis loss, shuttle loss, appendix displacer gap loss, gas leakage loss, finite speed loss, piston friction loss, pressure drop loss, heat conduction loss, mechanical loss and imperfect heat transfer, are considered and embedded into the basic control equations. The non-equilibrium thermal model is adopted for the regenerator to capture the oscillating features of the gas and solid temperatures. To improve the numerical stability and accuracy, the implicit second-order time difference scheme and the second-order upwind scheme are adopted for discretizing the time differential terms and convective terms, respectively. Experimental validations are then conducted on a beta-type Stirling engine with the extensive experimental data for diverse working conditions. The results show that the developed model has better accuracies than the previous second-order models. Good agreements are achieved for predicting various critical system parameters, including pressure-volume diagram, indicated power, brake power, indicated efficiency, brake efficiency and mechanical efficiency. In particular, both the experiments and simulations show that the Stirling engine charged with helium tends to have much lower optimal working frequencies and poorer performances compared to the hydrogen system. Based on the analyses of the losses, it reveals that the pressure drop in the flow channels plays a critical role in shaping the different

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.

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.

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....

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

Development of a Low Inductance Linear Alternator for Stirling Power Convertors

Science.gov (United States)

Geng, Steven M.; Schifer, Nicholas A.

2017-01-01

The free-piston Stirling power convertor is a promising technology for high efficiency heat-to-electricity power conversion in space. Stirling power convertors typically utilize linear alternators for converting mechanical motion into electricity. The linear alternator is one of the heaviest components of modern Stirling power convertors. In addition, state-of-art Stirling linear alternators usually require the use of tuning capacitors or active power factor correction controllers to maximize convertor output power. The linear alternator to be discussed in this paper, eliminates the need for tuning capacitors and delivers electrical power output in which current is inherently in phase with voltage. No power factor correction is needed. In addition, the linear alternator concept requires very little iron, so core loss has been virtually eliminated. This concept is a unique moving coil design where the magnetic flux path is defined by the magnets themselves. This paper presents computational predictions for two different low inductance alternator configurations, and compares the predictions with experimental data for one of the configurations that has been built and is currently being tested.

Development of a Low-Inductance Linear Alternator for Stirling Power Convertors

Science.gov (United States)

Geng, Steven M.; Schifer, Nicholas A.

2017-01-01

The free-piston Stirling power convertor is a promising technology for high-efficiency heat-to-electricity power conversion in space. Stirling power convertors typically utilize linear alternators for converting mechanical motion into electricity. The linear alternator is one of the heaviest components of modern Stirling power convertors. In addition, state-of-the-art Stirling linear alternators usually require the use of tuning capacitors or active power factor correction controllers to maximize convertor output power. The linear alternator to be discussed in this paper eliminates the need for tuning capacitors and delivers electrical power output in which current is inherently in phase with voltage. No power factor correction is needed. In addition, the linear alternator concept requires very little iron, so core loss has been virtually eliminated. This concept is a unique moving coil design where the magnetic flux path is defined by the magnets themselves. This paper presents computational predictions for two different low inductance alternator configurations. Additionally, one of the configurations was built and tested at GRC, and the experimental data is compared with the predictions.

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.

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.

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...

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...

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.

Free-Piston Stirling Power Conversion Unit for Fission Surface Power, Phase I Final Report

Science.gov (United States)

Wood, J. Gary; Buffalino, Andrew; Holliday, Ezekiel; Penswick, Barry; Gedeon, David

2010-01-01

This report summarizes the design of a 12 kW dual opposed free-piston Stirling convertor and controller for potential future use in space missions. The convertor is heated via a pumped NaK loop and cooling is provided by a pumped water circuit. Convertor efficiency is projected at 27 percent (AC electrical out/heat in). The controller converts the AC electrical output to 120 Vdc and is projected at 91 percent efficiency. A mechanically simple arrangement, based on proven technology, was selected in which the piston is resonated almost entirely by the working space pressure swing, while the displacer is resonated by planar mechanical springs in the bounce space.

Financing CHP Projects at Wastewater Treatment Facilities with Clean Water State Revolving Funds

Science.gov (United States)

This factsheet provides information about CHP at wastewater treatment facilities, including applications, financial challenges, and financial opportunities, such as the Clean Water State Revolving Fund.

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

Science.gov (United States)

Wilson, Scott D.; Wong, Wayne A.

2015-01-01

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

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.

Investment in new power generation under uncertainty: Benefits of CHP vs. condensing plants in a copula-based analysis

International Nuclear Information System (INIS)

Westner, Günther; Madlener, Reinhard

2012-01-01

In this paper, we apply a spread-based real options approach to analyze the decision-making problem of an investor who has the choice between an irreversible investment in a condensing power plant without heat utilization and a plant with combined heat-and-power (CHP) generation. Our investigation focuses on large-scale fossil-fueled generation technologies and is based on a stochastic model that uses copula functions to provide the input parameters of the real options model. We define the aggregated annual spread as assessment criteria for our investigation since it contains all relevant volatile input parameters that have an impact on the evaluation of investment decisions. We show that the specific characteristics of CHP plants, such as additional revenues from heat sales, promotion schemes, specific operational features, and a beneficial allocation of CO 2 allowances, have a significant impact on the option value and therefore on the optimal timing for investment. For the two fossil-fueled CHP technologies investigated (combined-cycle gas turbine and steam turbine), we conclude from our analysis that a high share of CHP generation reduces the risk exposure for the investor. The maximal possible CHP generation depends significantly on the local heat demand in the surroundings of the power plant. Considering this, the size of the heat sink available could gain more relevance in the future selection process of sites for new large-scale fossil power plants.

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.

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.

Overview 2004 of NASA Stirling-Convertor CFD-Model Development and Regenerator R&D Efforts

Science.gov (United States)

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

2005-01-01

This paper reports on accomplishments in 2004 in development of Stirling-convertor CFD model at NASA GRC and via a NASA grant, a Stirling regenerator-research effort being conducted via a NASA grant (a follow-on effort to an earlier DOE contract), and a regenerator-microfabrication contract for development of a "next-generation Stirling regenerator." Cleveland State University is the lead organization for all three grant/contractual efforts, with the University of Minnesota and Gedeor Associates as subcontractors. Also, the Stirling Technology Co. and Sunpower, Inc. are both involved in all three efforts, either as funded or unfunded participants. International Mezzo Technologies of Baton Rouge, LA is the regenerator fabricator for the regenerator-microfabrication contract. Results of the efforts in these three areas are summarized.

A combination of Stirling engine and high-efficiency boiler. Microsize cogeneration unit for heat and power supply; Stirlingmotor und Brennwertkessel vereint. Mikro-Waermekraftkopplung liefert Strom und Waerme

Energy Technology Data Exchange (ETDEWEB)

Donnerbauer, R.

2001-03-01

Apart from the heat pump and fuel cell, there is another new development: At the ISH in March, the Dutch producer EnAtEc intends to present a microsize cogeneration unit consisting of a gas-fuelled high-efficiency boiler and a free-piston Stirling motor. [German] Sind die Wirkungsgrade in der Heiztechnik ausgenutzt? Auf die Frage 'Was kommt nach der Brennwerttechnik?' gibt es jetzt neben Waermepumpe und Brennstoffzelle eine neue Antwort. Zur kommenden ISH Ende Maerz hat die niederlaendische Firma EnAtEc die Vorstellung einer 'Mikro-Waermekraftkopplung' ({mu}WK) angekuendigt. Das Geraet kombiniert einen Gas-Brennwertkessel mit einer Freikolben-Stirlingmaschine. (orig.)

External Magnetic Field Reduction Techniques for the Advanced Stirling Radioisotope Generator

Science.gov (United States)

Niedra, Janis M.; Geng, Steven M.

2013-01-01

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

The effectiveness of heat pumps as part of CCGT-190/220 Tyumen CHP-1

Directory of Open Access Journals (Sweden)

Tretyakova Polina

2017-01-01

Full Text Available The article considers the possibility of increasing the energy efficiency of CCGT-190/220 Tyumen CHP-1 due to the utilization of low-grade heat given off in the condenser unit of the steam turbine. To assess the effectiveness of the proposed system, the indexes of thermal efficiency are given. As a result of a research the following conclusions are received: The heat-transfer agent heat pump, when heated uses low-grade heat TPP and increases heat output, but consumes the electricity. Using a heat pump is effective for a small temperature difference between the condenser and the evaporator. Good example is heating water before chemical treatment. This method is more efficient than using a replacement boiler and it is used in steam selection.

Flue gas condensation in straw fired CHP plants; Roeggaskondensation i halmfyrede kraftvarmeanlaeg

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-06-15

The high price of straw and a general demand for increased use of straw in power and heat production are expected to result in an increased need for efficient fuel utilization. The use of flue gas condensation in straw fired CHP plants can contribute to a higher exploitation of energy, and at the same time open of the possibility of utilization of wet (cheaper) fuels without energy loss. Furthermore flue gas condensation can contribute to the flue gas cleaning process through removal of HCl and SO{sub 2} as well as in particle cleaning in wet cleaning processes. With starting point in a straw fired CHP plant the technical and economic consequences of installation of a flue gas condensation system are investigated. Fuel exploitation and power/heat production distribution is included in the investigation. (BA)

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

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

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.

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

Quality Assurance in Education: Current Debates. A Report on a SOED-Sponsored Seminar (Stirling, Scotland, United Kingdom, June 1992).

Science.gov (United States)

Stronach, Ian, Ed.

Proceedings of a workshop held at the University of Stirling, Scotland, to critically examine issues in quality assurance (QA) in education are provided in this document. QA is the generic title for a series of business-management models that have been applied to educational contexts to describe and promote school effectiveness. Five papers and…

Development of a CHP/DH system for the new town of Parand: An opportunity to mitigate global warming in Middle East

International Nuclear Information System (INIS)

Mostafavi Tehrani, S. Saeed; Saffar-Avval, M.; Mansoori, Z.; Behboodi Kalhori, S.; Abbassi, A.; Dabir, B.; Sharif, M.

2013-01-01

As a result of the worldwide concern about global warming, projects that target reduction of greenhouse gas emissions have gained a lot of interest. The idea of this paper is to recover exhaust hot gases of an existing gas turbine power plant to meet dynamic thermal energy requirements of a residential area (the new town of Parand) situated in the suburb of Tehran, and also use the rest of the heat source potential to feed a steam turbine cycle. In close proximity to this town, there are two GT plants: Parand (954 MW e ) and Rudeshur (790 MW e ). For handling the CHP/STC/DH plant, two methods are considered along with thermal load following operation strategy: maximum power generation (MPG) and minimum fuel consumption (MFC). Then, the alternatives are compared in terms of annual PES, CO 2 abatement and NPV. For the best design from environmental viewpoint (Parand CHP-B), PES, CO 2 abatement and NPV are calculated to be 27.31%, 2.56 million tons and 1491 million dollar, respectively. -- Highlights: • To propose a technical and financial methodology to evaluate CHP/DH projects. • To address environmental advantages of CHPs with conventional plants. • To present practical operation strategies to increase benefits of CHP/DH plants. • To report/compare benefits of various CHP/DH alternatives for a case study in Iran. • To conduct a comprehensive energy analysis of proposed CHP/DH design options

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.

Multi-objective optimization of Stirling engine using non-ideal adiabatic method

International Nuclear Information System (INIS)

Toghyani, Somayeh; Kasaeian, Alibakhsh; Ahmadi, Mohammad H.

2014-01-01

Highlights: • A multi-objective optimization is carried out for a Stirling engine. • The methods of TOPSIS, Fuzzy, and LINMAP are compared with each other in aspect of optimization. • The results are compared with the previous works for checking the model improvement. • A proper improvement is observed using TOPSIS when comparing with the others. - Abstract: In the recent years, remarkable attention is drawn to Stirling engine due to noticeable advantages, for instance a lot of resources such as biomass, fossil fuels and solar energy can be applied as heat source. Great numbers of studies are conducted on Stirling engines and non-ideal adiabatic method is one of them. In the present study, the efficiency and the power loss due to pressure drop into the heat exchangers are optimized for a Stirling system using non-ideal adiabatic analysis and the second-version Non-dominated Sorting Genetic Algorithm. The optimized answers are chosen from the results using three decision-making methods. The applied methods were compared at last and the best results were obtained for the technique for order preference by similarity to ideal solution decision making method

TaCHP: a wheat zinc finger protein gene down-regulated by abscisic acid and salinity stress plays a positive role in stress tolerance.

Science.gov (United States)

Li, Cuiling; Lv, Jian; Zhao, Xin; Ai, Xinghui; Zhu, Xinlei; Wang, Mengcheng; Zhao, Shuangyi; Xia, Guangmin

2010-09-01

The plant response to abiotic stresses involves both abscisic acid (ABA)-dependent and ABA-independent signaling pathways. Here we describe TaCHP, a CHP-rich (for cysteine, histidine, and proline rich) zinc finger protein family gene extracted from bread wheat (Triticum aestivum), is differentially expressed during abiotic stress between the salinity-sensitive cultivar Jinan 177 and its tolerant somatic hybrid introgression cultivar Shanrong No.3. TaCHP expressed in the roots of seedlings at the three-leaf stage, and the transcript localized within the cells of the root tip cortex and meristem. TaCHP transcript abundance was higher in Shanrong No.3 than in Jinan 177, but was reduced by the imposition of salinity or drought stress, as well as by the exogenous supply of ABA. When JN17, a salinity hypersensitive wheat cultivar, was engineered to overexpress TaCHP, its performance in the face of salinity stress was improved, and the ectopic expression of TaCHP in Arabidopsis (Arabidopsis thaliana) also improved the ability of salt tolerance. The expression level of a number of stress reporter genes (AtCBF3, AtDREB2A, AtABI2, and AtABI1) was raised in the transgenic lines in the presence of salinity stress, while that of AtMYB15, AtABA2, and AtAAO3 was reduced in its absence. The presence in the upstream region of the TaCHP open reading frame of the cis-elements ABRE, MYBRS, and MYCRS suggests that it is a component of the ABA-dependent and -independent signaling pathways involved in the plant response to abiotic stress. We suggest that TaCHP enhances stress tolerance via the promotion of CBF3 and DREB2A expression.

Bernoulli-Carlitz and Cauchy-Carlitz numbers with Stirling-Carlitz numbers

OpenAIRE

Kaneko, Hajime; Komatsu, Takao

2017-01-01

Recently, the Cauchy-Carlitz number was defined as the counterpart of the Bernoulli-Carlitz number. Both numbers can be expressed explicitly in terms of so-called Stirling-Carlitz numbers. In this paper, we study the second analogue of Stirling-Carlitz numbers and give some general formulae, including Bernoulli and Cauchy numbers in formal power series with complex coefficients, and Bernoulli-Carlitz and Cauchy-Carlitz numbers in function fields. We also give some applications of Hasse-Teichm...

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…

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....

Emissions from decentralised CHP plants 2007 - Energinet.dk Environmental project no. 07/1882. Project report 5 - Emission factors and emission inventory for decentralised CHP production

Energy Technology Data Exchange (ETDEWEB)

Nielsen, Malene; Nielsen, Ole-Kenneth; Thomsen, M.

2010-06-15

Updated emission factors for decentralised combined heat and power (CHP) plants with a capacity < 25MWe have been estimated based on project emission measurements as well as emission measurements performed in recent years that were collected. The emission factors valid for 2006/2007 have been estimated for the plant technologies: Municipal solid waste (MSW) incineration plants, plants combusting straw or wood, natural gas fuelled reciprocating engines, biogas fuelled engines, natural gas fuelled gas turbines, gas oil fuelled reciprocating engines, gas oil fuelled gas turbines, steam turbines combusting residual oil and reciprocating engines combusting biomass producer gas based on wood. The emission factors for MSW incineration plants are much lower than the emission factors that were estimated for year 2000. The considerable reduction in the emission factors is a result of lower emission limit values in Danish legislation since 2006 that has lead to installation of new and improved flue gas cleaning systems in most MSW incineration plants. For CHP plants combusting wood or straw no major technical improvements have been implemented. The emission factors for natural gas fuelled reciprocating engines have been reduced since year 2000 as a result of technical improvements that have been carried out due to lower emission limit values in Danish legislation. The NO{sub x} emission factor for natural gas fuelled gas turbines has decreased 62 % since year 2000. This is a result of installation of low-NO{sub x} burners in almost all gas turbines that has been necessary to meet new emission limits in Danish legislation. The emission measurements programme included screening of the emissions of HCB, PCB, PCDD/-F and PBDD/-F. Compared to the Danish national emission decentralized CHP plants are major emission sources for CH{sub 4}, NO{sub x}, SO{sub 2}, heavy metals and HCB. (author)

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

Economic feasibility of CHP facilities fueled by biomass from unused agriculture land

DEFF Research Database (Denmark)

Pfeifer, Antun; Dominkovic, Dominik Franjo; Ćosić, Boris

2016-01-01

In this paper, the energy potential of biomass from growing short rotation coppice on unused agricultural land in the Republic of Croatia is used to investigate the feasibility of Combined Heat and Power (CHP) facilities fueled by such biomass. Large areas of agricultural land that remain unused...... work and is now used to investigate the conditions in which such energy facilities could be feasible. The overall potential of biomass from short rotation coppice cultivated on unused agricultural land in the scenarios with 30% of the area is up to 10PJ/year. The added value of fruit trees pruning...... biomass represents an incentive for the development of fruit production on such agricultural land. Sensitivity analysis was conducted for several parameters: cost of biomass, investment costs in CHP systems and combined change in biomass and technology cost....

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.

Putney Basketville Site Biomass CHP Analysis

Energy Technology Data Exchange (ETDEWEB)

Hunsberger, Randolph [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mosey, Gail [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2013-10-01

The U.S. Environmental Protection Agency (EPA) Office of Solid Waste and Emergency Response Center for Program Analysis developed the RE-Powering America's Land initiative to reuse contaminated sites for renewable energy generation when aligned with the community's vision for the site. The Putney, Vermont, Basketville site, formerly the location of a basket-making facility and a paper mill andwoolen mill, was selected for a feasibility study under the program. Biomass was chosen as the renewable energy resource based on abundant woody-biomass resources available in the area. Biomass combined heat and power (CHP) was selected as the technology due to nearby loads, including Putney Paper and Landmark College.

Operational Strategies for a Portfolio of Wind Farms and CHP Plants in a Two-Price Balancing Market

DEFF Research Database (Denmark)

Hellmers, Anna; Zugno, Marco; Skajaa, Anders

2015-01-01

In this paper we explore the portfolio effect of a system consisting of a Combined Heat and Power (CHP) plant and a wind farm. The goal is to increase the overall profit of the portfolio by reducing imbalances, and consequently their implicit penalty in a two-price balancing market for electricity......-horizon fashion, so that forecasts for heat demand, wind power production and market prices are updated at each iteration. We conclude that the portfolio strategy is the most profitable due to the two-price structure of the balancing market. This encourages producers to handle their imbalances outside the market........ We investigate two different operational strategies, which differ in whether the CHP plant and the wind farm are operated jointly or independently, and we evaluate their economic performance on a real case study based on a CHP-wind system located in the western part of Denmark. We present...

Calorimetric studies and lessons on fires and explosions of a chemical plant producing CHP and DCPO

International Nuclear Information System (INIS)

Hsu, Jing-Ming; Su, Mao-Sheng; Huang, Chiao-Ying; Duh, Yih-Shing

2012-01-01

Highlights: ► We analyzed fire and explosion incidents in a plant producing CHP and DCPO. ► Data from calorimeters reveal causes and phenomena associated with the incidents. ► The credible worst scenario was thermal explosion. ► Incidents may be avoided by implementing DIERS methodology. - Abstract: Cumene hydroperoxide (CHP) has been used in producing phenol, dicumyl peroxide (DCPO) and as an initiator for synthesizing acrylonitrile–butadiene–styrene (ABS) resin by copolymerization in Taiwan. Four incidents of fire and explosion induced by thermal runaway reactions were occurred in a same plant producing CHP, DCPO and bis-(tert-butylperoxy isopropyl) benzene peroxide (BIBP). The fourth fire and explosion occurred in the CHP reactor that resulted in a catastrophic damage in reaction region and even spread throughout storage area. Descriptions on the occurrences of these incidents were assessed by the features of processes, reaction schemes and unexpected side reactions. Calorimetric data on thermokinetics and pressure were used for explaining the practical consequences or which the worst cases encountered in this kind of plant. Acceptable risk associated with emergency relief system design is vital for a plant producing organic peroxide. These basic data for designing an inherently safer plant can be conducted from adiabatic calorimetry. An encouraging deduction has been drawn here, these incidents may be avoided by the implementation of API RP 520, API RP 521, DIERS technology, OSHA 1910.119 and AIChE's CCPS recommended PSM elements.

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.

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

Optimal Design and Operation of A Syngas-fuelled SOFC Micro-CHP System for Residential Applications in Different Climate Zones in China

DEFF Research Database (Denmark)

Yang, Wenyuan; Liso, Vincenzo; Zhao, Yingru

2013-01-01

heat-to-power load ratio. Therefore, the aim of this study is to investigate the optimal design and operation of a syngas-fuelled SOFC micro-CHP system for small households located in five different climate zones in China. The ability of the micro-CHP to cover the heat and electricity demand of a 70m2...... demand. Numerical simulations are conducted in Matlab environment. System design trade-offs are discussed to determine the optimal match between the energy demand of the household for different climates across China and the energy supply of the micro-CHP during the whole year. Moreover, criteria...

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.

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.

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)

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...

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.

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. 

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.

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

Science.gov (United States)

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

2001-01-01

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

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.

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…

Innovative Hybrid CHP systems for high temperature heating plant in existing buildings

NARCIS (Netherlands)

de Santoli, Livio; Lo Basso, Gianluigi; Nastasi, B.; d’Ambrosio Alfano, Francesca R.; Mazzarella and Piercarlo, Livio

2017-01-01

This paper deals with the potential role of new hybrid CHP systems application providing both electricity and heat which are compatible with the building architectural and landscape limitations. In detail, three different plant layout options for high temperature heat production along with the

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

Thermo-economic multi-objective optimization of solar dish-Stirling engine by implementing evolutionary algorithm

International Nuclear Information System (INIS)

Ahmadi, Mohammad H.; Sayyaadi, Hoseyn; Mohammadi, Amir H.; Barranco-Jimenez, Marco A.

2013-01-01

Highlights: • Thermo-economic multi-objective optimization of solar dish-Stirling engine is studied. • Application of the evolutionary algorithm is investigated. • Error analysis is done to find out the error through investigation. - Abstract: In the recent years, remarkable attention is drawn to Stirling engine due to noticeable advantages, for instance a lot of resources such as biomass, fossil fuels and solar energy can be applied as heat source. Great number of studies are conducted on Stirling engine and finite time thermo-economic is one of them. In the present study, the dimensionless thermo-economic objective function, thermal efficiency and dimensionless power output are optimized for a dish-Stirling system using finite time thermo-economic analysis and NSGA-II algorithm. Optimized answers are chosen from the results using three decision-making methods. Error analysis is done to find out the error through investigation

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.

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.

Neural network-based control of an intelligent solar Stirling pump

International Nuclear Information System (INIS)

Tavakolpour-Saleh, A.R.; Jokar, H.

2016-01-01

In this paper, an ANN (artificial neural network) control system is applied to a novel solar-powered active LTD (low temperature differential) Stirling pump. First, a mathematical description of the proposed Stirling pump is presented. Then, optimum operating frequencies of the converter corresponding to different operating conditions (i.e. different sink and source temperatures and water heads) are investigated using the proposed mathematical framework. It is found that the proposed complex mathematical scheme has a very slow convergence and thus, is not appropriate for real-time implementation of the model-based controller. Consequently, a NN (neural network) model with a lower complexity is proposed to learn the simulation data obtained from the mathematical model. The designed neural network controller is thus applied to a digital processor to effectively tune the converter frequency so that a maximum output power is acquired. Finally, the performance of the proposed mechatronic system is evaluated experimentally. The experimental results clearly demonstrate the feasibility of pumping water at low temperature difference under variable operating conditions using the proposed intelligent Stirling converter. - Highlights: • A novel intelligent solar-powered active LTD Stirling pump was introduced. • A neural network controller was used to tune the converter speed. • The intelligent converter was able to adapt itself to different operating conditions. • It was possible to excite the water column with its resonance mode. • Experimental results showed the effectiveness of the proposed converter.

A novel method to hit the limit temperature of Stirling-type cryocooler

Science.gov (United States)

Wang, Jue; Pan, Changzhao; Zhang, Tong; Luo, Kaiqi; Zhou, Yuan; Wang, Junjie

2018-02-01

The Stirling-type cryocooler with its compact size and high efficiency is always expected to obtain its temperature limit of below 3 K. However, the pressure drop losses caused by high-frequency oscillation create large obstacles for this objective. This paper reports a novel thermal-driven Stirling-type cryocooler to obtain the lowest temperature of a Stirling-type cryocooler. The advantages of a thermal-driven cryocooler (Vuilleumier cryocooler) and pulse tube cryocooler are combined with a new type of cryocooler, called the Vuilleumier gas-coupling pulse tube hybrid cryocooler (VM-PT). A prototype of the VM-PT was recently developed and optimized in our laboratory. By using helium-4 as the working gas and magnetic regenerative materials (HoCu2 and Er3Ni), the lowest temperature of 2.5 K was obtained, which can be regarded as an important breakthrough for the Stirling-type cryocooler to achieve its limit temperature of below 3 K. It can supply >30 mW cooling power at 4.2 K and >500 mW cooling power at 20 K simultaneously. Theoretically, it is feasible to use this VM-PT for cooling the superconducting devices in space applications.

Trade-Off Study for an STC 70 W Stirling Engine

Science.gov (United States)

Qiu, Songgang; Peterson, Allen A.; Augenblick, Jack E.

2005-02-01

A high-efficiency, low-weight free-piston Stirling generator, RG-70L, has been conceptually designed. This paper reports the detailed trade-off study of newly designed RG-70L. The trades of operating frequency and piston/displacer strokes on Stirling convertor mass and efficiency are discussed. This paper shows how the operating frequency and strokes were optimized based on the trades. Losses associated with increased frequency were fully investigated and the results are discussed in the paper. Various optional linear alternator configurations are also presented and the estimated masses are reported.

Thermodynamic model to study a solar collector for its application to Stirling engines

International Nuclear Information System (INIS)

Abdollahpour, Amir; Ahmadi, Mohammad H.; Mohammadi, Amir H.

2014-01-01

Highlights: • A thermodynamic model is presented to study a solar collector for its application to Stirling engines. • The parabolic collector is analyzed based on optical and thermal. • Effects of changing some conditions and parameters are studied. - Abstract: Energy production through clean and green sources has been paid attention over the last decades owing to high energy consumption and environmental emission. Solar energy is one of the most useful energy sources. Due to high investment cost of centralized generation of electricity and considerable loss in the network, it is necessary to look forward to decentralized electricity generation technologies. Stirling engines have high efficiency and are able to be coupled with solar energy which cannot be applied in internal combustion engines. Solar Stirling engines can be commercialized and used to generate decentralized electricity in small to medium levels. One of the most important steps to set up an efficient solar Stirling engine is choosing and designing the collector. In this study, a solar parabolic collector with 3500 W of power for its application to Stirling engines was designed and analyzed (It is the thermal inlet power for a Stirling engine). We studied the parabolic collector based on optical and thermal analysis. In this case, solar energy is focused by a concentrating mirror and transferred to a pipe containing fluid. MATLAB software was used for obtaining the parameters of the collector, with respect to the geographic, temporal, and environmental conditions, fluid inlet temperature and some other considerations. After obtaining the results of the design, we studied the effects of changing some conditions and parameters such as annular space pressure, type of the gas, wind velocity, environment temperature and absorber pipe coating

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

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.

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

Performance Testing of a High Temperature Linear Alternator for Stirling Convertors

Science.gov (United States)

Metscher, Jonathan F.; Geng, Steven M.

2016-01-01

The NASA Glenn Research Center has conducted performance testing of a high temperature linear alternator (HTLA) in support of Stirling power convertor development for potential future Radioisotope Power Systems (RPS). The high temperature linear alternator is a modified version of that used in Sunpower's Advanced Stirling Convertor (ASC), and is capable of operation at temperatures up to 200 deg. Increasing the temperature capability of the linear alternator could expand the mission set of future Stirling RPS designs. High temperature Neodymium-Iron-Boron (Nd-Fe-B) magnets were selected for the HTLA application, and were fully characterized and tested prior to use. Higher temperature epoxy for alternator assembly was also selected and tested for thermal stability and strength. A characterization test was performed on the HTLA to measure its performance at various amplitudes, loads, and temperatures. HTLA endurance testing at 200 deg is currently underway.

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

Science.gov (United States)

Walsh, Michael M.

1984-01-01

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

Preliminary experimental investigation of a natural gas-fired ORC-based micro-CHP system for residential buildings

International Nuclear Information System (INIS)

Farrokhi, M.; Noie, S.H.; Akbarzadeh, A.A.

2014-01-01

The continual increases in energy demand and greenhouse gas emissions, call for efficient use of energy resources. Decentralized combined heat and power (CHP) technology provides an alternative for the world to meet and solve energy-related problems including energy shortages, energy supply security, emission control and conservation of energy. This paper presents the preliminary results of an experimental investigation of a natural gas-fired micro-CHP system for residential buildings based on an organic Rankine cycle (ORC). Isopentane was used as the ORC working fluid in consideration of several criteria including its environmentally-friendly characteristics. Experiments were conducted to evaluate the performance of the developed system at different heat source temperatures of nominally 85, 80, 75, 70, and 65 °C. The maximum electrical power output of 77.4 W was generated at heating water entry temperature of 84.1 °C, corresponding to net cycle electrical efficiency of 1.66%. Further work will be done with a view to increasing the cycle electrical efficiency by using more efficient components, in particular the expander and generator. - Highlights: •A natural gas-fired ORC-based micro-scale CHP system has been developed and tested. •The good agreement between the mechanical and gross power validates the assumptions. •A vane expander suits a micro-CHP system based on an organic Rankine cycle. •A vane expander does not suit power generation by a Trilateral Flash Cycle (TFC). •Domestic gas-fired ORC systems may reduce reliance on central power stations

Calorimetric studies and lessons on fires and explosions of a chemical plant producing CHP and DCPO

Energy Technology Data Exchange (ETDEWEB)

Hsu, Jing-Ming; Su, Mao-Sheng; Huang, Chiao-Ying [Department of Occupational Safety and Health, Chia Nan University of Pharmacy and Science, Tainan, Taiwan, ROC (China); Duh, Yih-Shing, E-mail: yihshingduh@yahoo.com.tw [Department of Safety, Health and Environmental Engineering, National United University, No. 1 Lien-Da, Miaoli, Taiwan, ROC (China)

2012-05-30

Highlights: Black-Right-Pointing-Pointer We analyzed fire and explosion incidents in a plant producing CHP and DCPO. Black-Right-Pointing-Pointer Data from calorimeters reveal causes and phenomena associated with the incidents. Black-Right-Pointing-Pointer The credible worst scenario was thermal explosion. Black-Right-Pointing-Pointer Incidents may be avoided by implementing DIERS methodology. - Abstract: Cumene hydroperoxide (CHP) has been used in producing phenol, dicumyl peroxide (DCPO) and as an initiator for synthesizing acrylonitrile-butadiene-styrene (ABS) resin by copolymerization in Taiwan. Four incidents of fire and explosion induced by thermal runaway reactions were occurred in a same plant producing CHP, DCPO and bis-(tert-butylperoxy isopropyl) benzene peroxide (BIBP). The fourth fire and explosion occurred in the CHP reactor that resulted in a catastrophic damage in reaction region and even spread throughout storage area. Descriptions on the occurrences of these incidents were assessed by the features of processes, reaction schemes and unexpected side reactions. Calorimetric data on thermokinetics and pressure were used for explaining the practical consequences or which the worst cases encountered in this kind of plant. Acceptable risk associated with emergency relief system design is vital for a plant producing organic peroxide. These basic data for designing an inherently safer plant can be conducted from adiabatic calorimetry. An encouraging deduction has been drawn here, these incidents may be avoided by the implementation of API RP 520, API RP 521, DIERS technology, OSHA 1910.119 and AIChE's CCPS recommended PSM elements.

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....

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.

Energy policy responses to the climate change challenge: The consistency of European CHP, renewables and energy efficiency policies

International Nuclear Information System (INIS)

Grohnheit, P.E.

1999-09-01

This report is Volume 14 of individual reports of the Shared Analysis Project prepared for the European Commission, Directorate General for Energy. The three major objectives of the project were: to design a common framework of energy analysis that aimed to involve all Member States and the experts of industrial research groups (the shared approach to energy analysis); To analyse generic EU-wide issues important for energy policy and for future energy demand and production, putting particular emphasis on world energy market trends, strategic energy policy responses to the Kyoto process, and evaluation of response strategies to increasing energy import dependence and to climate change activities; to carry out quantitative analyses of energy trends and scenarios as an input for discussion. The present volume considers three main issues concerning energy policy responses to the climate change challenge: the penetration of CHP and renewables according to official objectives, focusing on infrastructure and institutions rather than technology; the consistency of promotion of CHP, renewables and energy savings at the same time; consumers' choices and priorities in a liberalised market. The volume describes examples of policies in several Member States for these technologies with emphasis on CHP for both large-scale and small-scale district heating systems. The penetration of CHP technologies is analysed quantitatively using a traditional optimisation model approach for stylised regions with heat markets suitable for CHP and facing a competitive European market for electricity. The Joint Final Report of the project, titled 'Economic Foundations for Energy Policy' is published as a Special Issue of Energy in Europe, December 1999. All reports are available on the Internet, www.shared-analysis.fhg.de/ The project started in January 1998, involving about 100 months of scientific labour. The project consortium consisted of nine member institutes co-ordinated by the Fraunhofer

Economic feasibility of CHP facilities fueled by biomass from unused agriculture land

DEFF Research Database (Denmark)

Pfeifer, Antun; Dominkovic, Dominik Franjo; Ćosić, Boris

2016-01-01

In this paper, the energy potential of biomass from growing short rotation coppice on unused agricultural land in the Republic of Croatia is used to investigate the feasibility of Combined Heat and Power (CHP) facilities fueled by such biomass. Large areas of agricultural land that remain unused...

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.

Economic potentials of CHP connected to district heat systems in Germany. Implementation of the EU Efficiency Directive

International Nuclear Information System (INIS)

Eikmeier, Bernd

2015-01-01

The EU Efficiency Directive (2012/27/EU) is requiring all member states to carry out an evaluation of the potential for highly efficient CHP and the efficient use of district heating and cooling by December 2015. The German Federal Ministry of Economic Affairs and Energy appointed this task to the Fraunhofer Institute for Manufacturing and Advanced Materials, division for Energy Systems Analysis (formerly Bremer Energie Institut) in conjunction with other partners. The results for the sector district- and communal heating with CHP, sub-sectors private households, trade and services industry, are presented in this article.

EFFICIENCY OF THE USE OF HEAT PUMPS ON THE CHP PLANTS

Directory of Open Access Journals (Sweden)

Juravleov A.A.

2007-04-01

Full Text Available The work is dedicated to the calculus of the efficiency of the use of heat pumps on the CHP plants. There are presented the interdependences between the pay-back period and NPV of heat pump and the price of 1 kWt of thermal power of heat pump and of the tariff of electricity.

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

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

International Nuclear Information System (INIS)

Dochat, G.R.; Dhar, M.

1991-01-01

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

Final design of a free-piston hydraulic advanced Stirling conversion system

Science.gov (United States)

Wallace, D. A.; Noble, J. E.; Emigh, S. G.; Ross, B. A.; Lehmann, G. A.

1991-01-01

Under the US Department of Energy's (DOEs) Solar Thermal Technology Program, Sandia National Laboratories is evaluating heat engines for solar distributed receiver systems. The final design is described of an engineering prototype advanced Stirling conversion system (ASCS) with a free-piston hydraulic engine output capable of delivering about 25 kW of electric power to a utility grid. The free-piston Stirling engine has the potential for a highly reliable engine with long life because it has only a few moving parts, has noncontacting bearings, and can be hermetically sealed. The ASCS is designed to deliver maximum power per year over a range of solar input with a design life of 30 years (60,000 h). The system includes a liquid Nak pool boiler heat transport system and a free-piston Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator.

Final design of a free-piston hydraulic advanced Stirling conversion system

Science.gov (United States)

Wallace, D. A.; Noble, J. E.; Emigh, S. G.; Ross, B. A.; Lehmann, G. A.

Under the US Department of Energy's (DOEs) Solar Thermal Technology Program, Sandia National Laboratories is evaluating heat engines for solar distributed receiver systems. The final design is described of an engineering prototype advanced Stirling conversion system (ASCS) with a free-piston hydraulic engine output capable of delivering about 25 kW of electric power to a utility grid. The free-piston Stirling engine has the potential for a highly reliable engine with long life because it has only a few moving parts, has noncontacting bearings, and can be hermetically sealed. The ASCS is designed to deliver maximum power per year over a range of solar input with a design life of 30 years (60,000 h). The system includes a liquid Nak pool boiler heat transport system and a free-piston Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator.