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Sample records for brayton cycle power systems

  1. Nuclear reactor closed Brayton cycle space power conversion systems

    International Nuclear Information System (INIS)

    This paper presents the past history, present status and future prospects for closed Brayton cycle power conversion systems to be used in space when requirements have been established. Since there is a classic lack of coordination between advanced technology and its perceived need that can be strongly affected by associated factors, recommendations will be made to assist in the current situation. 4 refs

  2. Combined-Brayton cycle, space nuclear power systems

    International Nuclear Information System (INIS)

    Because it is a widely recognized dynamic space conversion system, the Brayton cycle has been studied in France since several years, especially within the framework of a limited space program. A recuperated cycle of 20 to 30 kWe has been considered so far. However, possible applications could evolve and the need for an extended, diversified utilization of the Brayton cycle could appear. So, for Lunar or Mars bases which would accept large radiators and can benefit from a certain gravity level, combined cycle systems could be proposed. Following a reference to past works on space combined cycles, a possible association of a Brayton cycle with a thermoionic reactor is presented. The power level of a 'Topaz-2' type space nuclear system can be boosted from 8 kWe to around 36 to 53 kWe, at the expense of a large radiator of course. Furthermore, combined Brayton-Rankine, organic (toluene) or steam, cycles can pave the way to a simpler gas-cooled, particle bed reactor concept. A particular arrangement of HeXe heater and boiler or steam generator in series is proposed. It makes it possible to lower the reactor inlet temperature, which is quite adequate for the use of light water as moderator. Oustanding net efficiencies of 25.8 to 27.6 per cent, given the reactor temperature profile, are obtained. Consequences on the reactor design are mentioned

  3. Closed Brayton cycle power conversion systems for nuclear reactors :

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Steven A.; Lipinski, Ronald J.; Vernon, Milton E.; Sanchez, Travis

    2006-04-01

    This report describes the results of a Sandia National Laboratories internally funded research program to study the coupling of nuclear reactors to gas dynamic Brayton power conversion systems. The research focused on developing integrated dynamic system models, fabricating a 10-30 kWe closed loop Brayton cycle, and validating these models by operating the Brayton test-loop. The work tasks were performed in three major areas. First, the system equations and dynamic models for reactors and Closed Brayton Cycle (CBC) systems were developed and implemented in SIMULINKTM. Within this effort, both steady state and dynamic system models for all the components (turbines, compressors, reactors, ducting, alternators, heat exchangers, and space based radiators) were developed and assembled into complete systems for gas cooled reactors, liquid metal reactors, and electrically heated simulators. Various control modules that use proportional-integral-differential (PID) feedback loops for the reactor and the power-conversion shaft speed were also developed and implemented. The simulation code is called RPCSIM (Reactor Power and Control Simulator). In the second task an open cycle commercially available Capstone C30 micro-turbine power generator was modified to provide a small inexpensive closed Brayton cycle test loop called the Sandia Brayton test-Loop (SBL-30). The Capstone gas-turbine unit housing was modified to permit the attachment of an electrical heater and a water cooled chiller to form a closed loop. The Capstone turbine, compressor, and alternator were used without modification. The Capstone systems nominal operating point is 1150 K turbine inlet temperature at 96,000 rpm. The annular recuperator and portions of the Capstone control system (inverter) and starter system also were reused. The rotational speed of the turbo-machinery is controlled by adjusting the alternator load by using the electrical grid as the load bank. The SBL-30 test loop was operated at

  4. Brayton-Cycle Baseload Power Tower CSP System

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Bruce

    2013-12-31

    The primary objectives of Phase 2 of this Project were: 1. Engineer, fabricate, and conduct preliminary testing on a low-pressure, air-heating solar receiver capable of powering a microturbine system to produce 300kWe while the sun is shining while simultaneously storing enough energy thermally to power the system for up to 13 hours thereafter. 2. Cycle-test a high-temperature super alloy, Haynes HR214, to determine its efficacy for the system’s high-temperature heat exchanger. 3. Engineer the thermal energy storage system This Phase 2 followed Wilson’s Phase 1, which primarily was an engineering feasibility study to determine a practical and innovative approach to a full Brayton-cycle system configuration that could meet DOE’s targets. Below is a summary table of the DOE targets with Wilson’s Phase 1 Project results. The results showed that a Brayton system with an innovative (low pressure) solar receiver with ~13 hours of dry (i.e., not phase change materials or molten salts but rather firebrick, stone, or ceramics) has the potential to meet or exceed DOE targets. Such systems would consist of pre-engineered, standardized, factory-produced modules to minimize on-site costs while driving down costs through mass production. System sizes most carefully analyzed were in the range of 300 kWe to 2 MWe. Such systems would also use off-the-shelf towers, blowers, piping, microturbine packages, and heliostats. Per DOE’s instructions, LCOEs are based on the elevation and DNI levels of Daggett, CA, for a 100 MWe power plant following 2 GWe of factory production of the various system components. Success criteria DOE targets Wilson system LCOE DOE’s gas price $6.75/MBtu 9 cents/kWh 7.7 cents/kWh LCOE Current gas price $4.71/MBtu NA 6.9 cents/kWh Capacity factor 75% (6500hr) 75-100% Solar fraction 85% (5585hr) >5585hr Receiver cost $170/kWe $50/kWe Thermal storage cost $20/kWhth $13/kWhth Heliostat cost $120/m2 $89.8/m2

  5. Operational Curves for HTGR's Coupled to Closed Brayton Cycle Power Conversion Systems

    International Nuclear Information System (INIS)

    Gas Cooled Reactors (GCR) that drive Closed Brayton Cycle (CBC) systems are being evaluated by the Department of Energy (DOE) Next Generation Program for high-efficiency electricity generation. This paper describes the operational performance of measured and predicted closed Brayton cycles. The measured results were obtained from an electrically driven closed Brayton cycle test loop that Sandia fabricated and has operating within the laboratories. The predicted behavior is based on integrated dynamic system models that are capable of predicting both the transient and steady state behavior of reactor driven Brayton cycle systems. Sandia contracted Barber Nichols Corporation to modify a Capstone C30 open-cycle Brayton engine so that it could be operated in a closed loop. We are currently operating the test loop to validate the models and to study control issues. Operation of the test-loop and developing the system models has allowed Sandia to develop and validate a set of tools and models that are being used to determine how nuclear reactors operate with gas turbine power conversion systems. Both measured and modeled operational performance curves will be presented to show how the electrical load (or power generated) varies as a function of shaft speed for various turbine inlet temperatures and for a fixed fill gas inventory. The measured and modeled behavior of the test loop both reveal the non-linear nature of the reactor and Brayton cycle loop because for a fixed electrical load there are two shaft speeds that can produce this steady-state power. Closer examination of the system of equations shows that only one of these steady-state solutions is dynamically stable. An active electronic control system will be required to operate at the more efficient but dynamically unstable point, and some means of controlling the flow via inventory control or bypass flow valves will also be required. (authors)

  6. Computational analysis of supercritical CO2 Brayton cycle power conversion system for fusion reactor

    International Nuclear Information System (INIS)

    Highlights: ► Computational analysis of S-CO2 Brayton cycle power conversion system. ► Validation of numerical model with literature data. ► Recompression S-CO2 Brayton cycle thermal efficiency of 42.44%. ► Reheating concept to enhance the cycle thermal efficiency. ► Higher efficiency achieved by the proposed concept. - Abstract: The Optimized Supercritical Cycle Analysis (OSCA) code is being developed to analyze the design of a supercritical carbon dioxide (S-CO2) driven Brayton cycle for a fusion reactor as part of the Modular Optimal Balance Integral System (MOBIS). This system is based on a recompression Brayton cycle. S-CO2 is adopted as the working fluid for MOBIS because of its easy availability, high density and low chemical reactivity. The reheating concept is introduced to enhance the cycle thermal efficiency. The helium-cooled lithium lead model AB of DEMO fusion reactor is used as reference in this paper.

  7. Preheating of fluid in a supercritical Brayton cycle power generation system at cold startup

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Steven A.; Fuller, Robert L.

    2016-07-12

    Various technologies pertaining to causing fluid in a supercritical Brayton cycle power generation system to flow in a desired direction at cold startup of the system are described herein. A sensor is positioned at an inlet of a turbine, wherein the sensor is configured to output sensed temperatures of fluid at the inlet of the turbine. If the sensed temperature surpasses a predefined threshold, at least one operating parameter of the power generation system is altered.

  8. Progress in investigating Brayton cycle conversion systems for future French Ariane 5 space power applications

    International Nuclear Information System (INIS)

    The present consideration of performance capabilities and system design requirements for a Brayton cycle conversion system usable by future Ariane 5 launch vehicle applications gives attention to such a power system's matching to available radiator concepts and dimensions, the use of direct or indirect waste heat transfer to the radiator and of simple or intercooled cycles, as well the consequences of gas cycle selection on reactor technology. The results presented are expected to be useful in the optimization of a 20-30 kW(e) system employing a liquid metal-cooled nuclear reactor in conjunction with a gas turbine energy conversion system. 10 references

  9. Nuclear reactor closed Brayton cycle power conversion system optimization trends for extra-terrestrial applications

    International Nuclear Information System (INIS)

    Extra-terrestrial exploration and development missions of the next century will require reliable, low-mass power generation modules of 100 kWe and more. These modules will be required to support both fixed-base and manned rover/explorer power needs. Low insolation levels at and beyond Mars and long periods of darkness on the moon make solar conversion less desirable for surface missions. For these missions, a closed Brayton cycle energy conversion system coupled with a reactor heat source is a very attractive approach. The authors conducted parametric studies to assess optimized system design trends for nuclear-Brayton systems as a function of operating environment and user requirements. The inherent design flexibility of the closed Brayton cycle energy conversion system permits ready adaptation of the system to future design constraints. This paper describes a dramatic contrast between system designs requiring man-rated shielding. The paper also considers the ramification of using indigenous materials to provide reactor shielding for a fixed-base power source

  10. Supercritical carbon dioxide Brayton power conversion cycle for battery optimized reactor integral system

    International Nuclear Information System (INIS)

    Supercritical carbon dioxide (SCO2) promises a high power conversion efficiency of the recompression Brayton cycle due to its excellent compressibility reducing the compression work at the bottom of the cycle and to a higher density than helium or steam decreasing the component size. The SCO2 Brayton cycle efficiency as high as 45% furnishes small sized nuclear reactors with economical benefits on the plant construction and maintenance. A 23 MWth lead-cooled Battery Optimized Reactor Integral System (BORIS) is being developed as an ultra-long-life, versatile-purpose, fast-spectrum reactor. BORIS is coupled to the SCO2 Brayton cycle needing less room relative to the Rankine steam cycle because of its smaller components. The SCO2 Brayton cycle of BORIS consists of a 16 MW turbine, a 32 MW high temperature recuperator, a 14 MW low temperature recuperator, an 11 MW precooler and 2 and 2.8 MW compressors. Entering six heat exchangers between primary and secondary system at 19.9 MPa and 663 K, the SCO2 leaves the heat exchangers at 19.9 MPa and 823 K. The promising secondary system efficiency of 45% was calculated by a theoretical method in which the main parameters include pressure, temperature, heater power, the turbine's, recuperators' and compressors' efficiencies, and the flow split ratio of SCO2 going out from the low temperature recuperator. Development of Modular Optimized Brayton Integral System (MOBIS) is being devised as the SCO2 Brayton cycle energy conversion cycle for BORIS. MOBIS consists of Loop Operating Brayton Optimization Study (LOBOS) for experimental Brayton cycle loop and Gas Advanced Turbine Operation Study (GATOS) for the SCO2 turbine. Liquid-metal Energy Exchanger Integral System (LEXIS) serves to couple BORIS and MOBIS. LEXIS comprises Physical Aspect Thermal Operation System (PATOS) for SCO2 thermal hydraulic characteristics, Shell-and-tube Overall Layout Optimization Study (SOLOS) for shell-and-tube heat exchanger, Printed-circuit Overall

  11. Brayton cycle conversion and additional French investigations on space nuclear power systems

    International Nuclear Information System (INIS)

    The French studies on space nuclear power systems were relatively active the past six years. It was anticipated that 20-kWe should have to be supplied to a spacecraft as soon as in 2005 and a reference near term liquid metal-cooled reactor using available terrestrial technologies as much as possible was mainly investigated. A Brayton cycle heat conversion has been adopted from the beginning and it remains considered. Because first applications are delayed, more attractive concepts can be contemplated. The basic idea is to take advantage of the Brayton cycle specific properties and for instance to use them for the temperature conditioning of the moderator of a thermal spectrum reactor. At first, the utilization of ZrH was thought mandatory, but recent proposals have prompted to use the conventional, effective light water material for that purpose. A gas cycle high pressure (HP) derivation technique makes it possible to maintain water within an adequate temperature range. A Brayton cycle adaptation and an example of a gas-cooled, particle bed fuel elements, H2O moderated reactor are briefly described. Key comparison data are given. Such concepts should be attractive from fuel inventory, mass, radition shielding and control points of view

  12. Carbon-Carbon Recuperators in Closed-Brayton-Cycle Nuclear Space Power Systems: A Feasibility Assessment

    Science.gov (United States)

    Barrett, Michael J.; Johnson, Paul K.

    2004-01-01

    The feasibility of using carbon-carbon recuperators in closed-Brayton-cycle (CBC) nuclear space power conversion systems (PCS) was assessed. Recuperator performance expectations were forecast based on projected thermodynamic cycle state values for a planetary mission. Resulting thermal performance, mass and volume for a plate-fin carbon-carbon recuperator were estimated and quantitatively compared with values for a conventional offset-strip-fin metallic design. Material compatibility issues regarding carbon-carbon surfaces exposed to the working fluid in the CBC PCS were also discussed.

  13. A four-year investigation of Brayton cycle systems for future French space power applications

    International Nuclear Information System (INIS)

    Within the framework of a joint program initiated in 1983 by the two French Government Agencies C.N.E.S. (Centre National d'Etudes Spatiales) and C.E.A. (Commissariat a l'Energie Atomique), in order to study space nuclear power systems for future ARIANE 5 applications, extensive investigations have dealt with the Brayton cycle, which has been selected as the energy conversion system. Several aspects can be mentioned in this field: matching of the power system to the available radiator dimensions up to 200 kWe, direct or indirect waste heat transfer to the radiator, the use of a recuperator, recent work on moderate (25 kWe) power levels, simulation studies related to various operating conditions, and general system optimization. A limited experimental program is starting on some crucial technology areas including a first contract to the Industry concerning the turbogenerator. Particular attention is being paid to the significance of the adoption of a Brayton cycle for space applications involving a nuclear heat source, which can be either a liquid-metal-cooled or a gas-cooled reactor. For a gas-cooled reactor, direct-cycle system, the relevance to the reactor technology and the concept for moderator thermal conditioning is particularly addressed

  14. Performance comparison of different supercritical carbon dioxide Brayton cycles integrated with a solar power tower

    International Nuclear Information System (INIS)

    In this study, a thermodynamic comparison of five supercritical carbon dioxide Brayton cycles integrated with a solar power tower was conducted. The Brayton cycles analyzed were simple Brayton cycle, regenerative Brayton cycle, recompression Brayton cycle, pre-compression Brayton cycle, and split expansion Brayton cycle. A complete mathematical code was developed to carry out the analysis. A heliostat field layout was generated and then optimized on an annual basis using the differential evolution method, which is an evolutionary algorithm. The heliostat field was optimized for optical performance and then integrated with the supercritical CO2 Brayton cycles. Using the results of the optimization, a comparison of net power outputs and thermal efficiencies for these cycles was performed. The findings demonstrated that the highest thermal efficiency was achieved using the recompression Brayton cycle, at June noontime. The maximum integrated system thermal efficiency using this cycle was 40% while the maximum thermal efficiency of this cycle alone was 52%. The regenerative Brayton cycle, although simpler in configuration, shows comparable performance to the recompression Brayton cycle. This analysis was carried out for Dhahran, Saudi Arabia. - Highlights: • The heliostat field of the solar power tower optimized and its optical efficiency identified. • Performance of the solar power tower integrated with five sCO2 Brayton Cycles was assessed. • Recompression supercritical CO2 Brayton cycle has the best performance. • The regenerative supercritical CO2 Brayton cycle has the second best performance

  15. Supercritical Carbon Dioxide Brayton Power Conversion Cycle Design for Optimized Battery-Type Integral Reactor System

    International Nuclear Information System (INIS)

    Supercritical carbon dioxide (SCO2) promises a high power conversion efficiency of the recompression Brayton cycle due to its excellent compressibility reducing the compression work at the bottom of the cycle and to a higher density than helium or steam decreasing the component size. Therefore, the high SCO2 Brayton cycle efficiency as high as 45 % furnishes small sized nuclear reactors with economical benefits on the plant construction and maintenance. A 23 MWth BORIS (Battery Optimized Reactor Integral System) is being developed as a multipurpose reactor. BORIS, an integral-type optimized fast reactor with an ultra long life core, is coupled to the SCO2 Brayton cycle needing less room relative to the Rankine steam cycle because of its smaller components. The SCO2 Brayton cycle of BORIS consists of a 16 MW turbine, a 32 MW high temperature recuperator, a 14 MW low temperature recuperator, an 11 MW pre-cooler and 2 and 2.8 MW compressors. Entering six heat exchangers between primary and secondary system at 19.9 MPa and 663 K, the SCO2 leaves the heat exchangers at 19.9 MPa and 823 K. The promising secondary system efficiency of 45 % was calculated by a theoretical method in which the main parameters include pressure, temperature, heater power, the turbine's, recuperators' and compressors' efficiencies, and the flow split ratio of SCO2 going out from the low temperature recuperator. Test loop SOLOS (Shell-and-tube Overall Layout Optimization Study) is utilized to develop advanced techniques needed to adopt the shell-and-tube type heat exchanger in the secondary loop of BORIS by studying the SCO2 behavior from both thermal and hydrodynamic points of view. Concurrently, a computational fluid dynamics (CFD) code analysis is being conducted to develop an optimal analytical method of the SCO2 turbine efficiency having the parameters of flow characteristics of SCO2 passing through buckets of the turbine. These simultaneous experimental and analytical methods for designing

  16. Brayton cycle conversion and additional French investigations on space nuclear power systems

    International Nuclear Information System (INIS)

    French activities in the field of space nuclear power systems have proceeded in anticipation that spacecraft would require such systems for the provision of 20 kW(e) by the year 2005. A liquid metal-cooled reactor patterned on well tested terrestrial technologies has been investigated which employs a Brayton-cycle heat-conversion system in such a way as to allow temperature conditioning of the moderator for a thermal-spectrum reactor. A high pressure gas cycle derivation technique makes it possible to maintain water within the requisite temperature range. The concept thus evolved is attractive in light of fuel inventory, mass, radiation shielding, and control points considerations. 7 refs

  17. Carbon-Carbon Recuperators in Closed-Brayton-Cycle Space Power Systems

    Science.gov (United States)

    Barrett, Michael J.; Johnson, Paul K.; Naples, Andrew G.

    2006-01-01

    The feasibility of using carbon-carbon (C-C) recuperators in conceptual closed-Brayton-cycle space power conversion systems was assessed. Recuperator performance expectations were forecast based on notional thermodynamic cycle state values for potential planetary missions. Resulting thermal performance, mass and volume for plate-fin C-C recuperators were estimated and quantitatively compared with values for conventional offset-strip-fin metallic designs. Mass savings of 30 to 60 percent were projected for C-C recuperators with effectiveness greater than 0.9 and thermal loads from 25 to 1400 kWt. The smaller thermal loads corresponded with lower mass savings; however, 60 percent savings were forecast for all loads above 300 kWt. System-related material challenges and compatibility issues were also discussed.

  18. Innovative biomass to power conversion systems based on cascaded supercritical CO2 Brayton cycles

    International Nuclear Information System (INIS)

    In the small to medium power range the main technologies for the conversion of biomass sources into electricity are based either on reciprocating internal combustion or organic Rankine cycle engines. Relatively low energy conversion efficiencies are obtained in both systems due to the thermodynamic losses in the conversion of biomass into syngas in the former, and to the high temperature difference in the heat transfer between combustion gases and working fluid in the latter. The aim of this paper is to demonstrate that higher efficiencies in the conversion of biomass sources into electricity can be obtained using systems based on the supercritical closed CO2 Brayton cycles (s-CO2). The s-CO2 system analysed here includes two cascaded supercritical CO2 cycles which enable to overcome the intrinsic limitation of the single cycle in the effective utilization of the whole heat available from flue gases. Both part-flow and simple supercritical CO2 cycle configurations are considered and four boiler arrangements are investigated to explore the thermodynamic performance of such systems. These power plant configurations, which were never explored in the literature for biomass conversion into electricity, are demonstrated here to be viable options to increase the energy conversion efficiency of small-to-medium biomass fired power plants. Results of the optimization procedure show that a maximum biomass to electricity conversion efficiency of 36% can be achieved using the cascaded configuration including a part flow topping cycle, which is approximately 10%-points higher than that of the existing biomass power plants in the small to medium power range. - Highlights: • Supercritical CO2 cycles are proposed for biomass to electricity conversion. • Four boiler design options are considered. • High total system efficiency is due to the part-flow cascaded configuration. • The efficiency is higher than that of other small/medium size alternative systems

  19. Concept definition study of small Brayton cycle engines for dispersed solar electric power systems

    Science.gov (United States)

    Six, L. D.; Ashe, T. L.; Dobler, F. X.; Elkins, R. T.

    1980-01-01

    Three first-generation Brayton cycle engine types were studied for solar application: a near-term open cycle (configuration A), a near-term closed cycle (configuration B), and a longer-term open cycle (configuration C). A parametric performance analysis was carried out to select engine designs for the three configurations. The interface requirements for the Brayton cycle engine/generator and solar receivers were determined. A technology assessment was then carried out to define production costs, durability, and growth potential for the selected engine types.

  20. Systems Analyses of Advanced Brayton Cycles

    Energy Technology Data Exchange (ETDEWEB)

    A.D. Rao; D.J. Francuz; J.D. Maclay; J. Brouwer; A. Verma; M. Li; G.S. Samuelsen

    2008-09-30

    The main objective is to identify and assess advanced improvements to the Brayton Cycle (such as but not limited to firing temperature, pressure ratio, combustion techniques, intercooling, fuel or combustion air augmentation, enhanced blade cooling schemes) that will lead to significant performance improvements in coal based power systems. This assessment is conducted in the context of conceptual design studies (systems studies) that advance state-of-art Brayton cycles and result in coal based efficiencies equivalent to 65% + on natural gas basis (LHV), or approximately an 8% reduction in heat rate of an IGCC plant utilizing the H class steam cooled gas turbine. H class gas turbines are commercially offered by General Electric and Mitsubishi for natural gas based combined cycle applications with 60% efficiency (LHV) and it is expected that such machine will be offered for syngas applications within the next 10 years. The studies are being sufficiently detailed so that third parties will be able to validate portions or all of the studies. The designs and system studies are based on plants for near zero emissions (including CO{sub 2}). Also included in this program is the performance evaluation of other advanced technologies such as advanced compression concepts and the fuel cell based combined cycle. The objective of the fuel cell based combined cycle task is to identify the desired performance characteristics and design basis for a gas turbine that will be integrated with an SOFC in Integrated Gasification Fuel Cell (IGFC) applications. The goal is the conceptualization of near zero emission (including CO{sub 2} capture) integrated gasification power plants producing electricity as the principle product. The capability of such plants to coproduce H{sub 2} is qualitatively addressed. Since a total systems solution is critical to establishing a plant configuration worthy of a comprehensive market interest, a baseline IGCC plant scheme is developed and used to study

  1. Applications of Brayton Cycle technology to space power

    International Nuclear Information System (INIS)

    The Closed Brayton (CBC) power conversion cycle can be used with a wide range of heat sources for space power applications. These heat source include solar concentrator, radioisotope, and reactor. With a solar concentrator, a solar dynamic ground demonstration test using existing Brayton components is being assembled for testing at NASA Lewis Research Center (LeRC). This 2-kWe system has a turbine inlet temperature of 1,015 K and is a complete end-to-end simulation of the Space Station Freedom solar dynamic design. With a radioisotope heat source, a 1-kWe Dynamic Isotope Power System (DIPS) is under development using an existing turbo alternator compressor (TAC) for testing at the same NASA-LeRC facility. This DIPS unit is being developed as a replacement to Radioisotopic Thermoelectric Generators (RTGs) to conserve the Pu-238 supply for interplanetary exploration. With a reactor heat source, many studies have been performed coupling the SP-100 reactor with a Brayton power conversion cycle. Applications for this reactor/CBC system include global communications satellites and electric propulsion for interplanetary exploration

  2. Power enhancement of the Brayton cycle by steam utilization

    Science.gov (United States)

    Jesionek, Krzysztof; Chrzczonowski, Andrzej; Ziółkowski, Paweł; Badur, Janusz

    2012-09-01

    The paper presents thermodynamic analysis of the gas-steam unit of the 65 MWe combined heat and power station. Numerical analyses of the station was performed for the nominal operation conditions determining the Brayton and combined cycle. Furthermore, steam utilization for the gas turbine propulsion in the Cheng cycle was analysed. In the considered modernization, steam generated in the heat recovery steam generator unit is directed into the gas turbine combustion chamber, resulting in the Brayton cycle power increase. Computational flow mechanics codes were used in the analysis of the thermodynamic and operational parameters of the unit.

  3. Brayton Isotope Power System (BIPS) facility specification

    Energy Technology Data Exchange (ETDEWEB)

    1976-05-31

    General requirements for the Brayton Isotope Power System (BIPS)/Ground Demonstration System (GDS) assembly and test facility are defined. The facility will include provisions for a complete test laboratory for GDS checkout, performance, and endurance testing, and a contamination-controlled area for assembly, fabrication, storage, and storage preparation of GDS components. Specifications, schedules, and drawings are included.

  4. Brayton Isotope Power System (BIPS) facility specification

    International Nuclear Information System (INIS)

    General requirements for the Brayton Isotope Power System (BIPS)/Ground Demonstration System (GDS) assembly and test facility are defined. The facility will include provisions for a complete test laboratory for GDS checkout, performance, and endurance testing, and a contamination-controlled area for assembly, fabrication, storage, and storage preparation of GDS components. Specifications, schedules, and drawings are included

  5. Motor starting a Brayton cycle power conversion system using a static inverter

    Science.gov (United States)

    Curreri, J. S.; Edkin, R. A.; Kruchowy, R.

    1973-01-01

    The power conversion module of a 2- to 15-kWe Brayton engine was motor started using a three-phase, 400-hertz static inverter as the power source. Motor-static tests were conducted for initial gas loop pressures of 10, 14, and 17 N/sq cm (15, 20, and 25 psia) over a range of initial turbine inlet temperatures from 366 to 550 K (200 to 530 F). The data are presented to show the effects of temperature and pressure on the motor-start characteristics of the rotating unit. Electrical characteristics during motoring are also discussed.

  6. Quantum Brayton cycle with coupled systems as working substance

    Science.gov (United States)

    Huang, X. L.; Wang, L. C.; Yi, X. X.

    2013-01-01

    We explore the quantum version of the Brayton cycle with a composite system as the working substance. The actual Brayton cycle consists of two adiabatic and two isobaric processes. Two pressures can be defined in our isobaric process; one corresponds to the external magnetic field (characterized by Fx) exerted on the system, while the other corresponds to the coupling constant between the subsystems (characterized by Fy). As a consequence, we can define two types of quantum Brayton cycle for the composite system. We find that the subsystem experiences a quantum Brayton cycle in one quantum Brayton cycle (characterized by Fx), whereas the subsystem's cycle is quantum Otto cycle in another Brayton cycle (characterized by Fy). The efficiency for the composite system equals to that for the subsystem in both cases, but the work done by the total system is usually larger than the sum of the work done by the two subsystems. The other interesting finding is that for the cycle characterized by Fy, the subsystem can be a refrigerator, while the total system is a heat engine. The result in this paper can be generalized to a quantum Brayton cycle with a general coupled system as the working substance.

  7. System Mass Variation and Entropy Generation in 100-kWe Closed-Brayton-Cycle Space Power Systems

    Science.gov (United States)

    Barrett, Michael J.; Reid, Bryan M.

    2004-02-01

    State-of-the-art closed-Brayton-cycle (CBC) space power systems were modeled to study performance trends in a trade space characteristic of interplanetary orbiters. For working-fluid molar masses of 48.6, 39.9 and 11.9 kg/kmol, peak system pressures of 1.38 and 3.0 MPa and compressor pressure ratios ranging from 1.6 to 2.4, total system masses were estimated. System mass increased as peak operating pressure increased for all compressor pressure ratios and molar mass values examined. Minimum mass point comparison between 72% He at 1.38 MPa peak and 94% He at 3.0 MPa peak showed an increase in system mass of 14%. Converter flow loop entropy generation rates were calculated for 1.38 and 3.0 MPa peak pressure cases. Physical system behavior was approximated using a pedigreed NASA-Glenn modeling code, Closed Cycle Engine Program (CCEP), which included realistic performance prediction for heat exchangers, radiators and turbomachinery.

  8. Supercritical Carbon Dioxide Brayton Cycle Energy Conversion System

    International Nuclear Information System (INIS)

    This report contains the description of the S-CO2 Brayton cycle coupled to KALIMER-600 as an alternative energy conversion system. For system development, a computer code was developed to calculate heat balance of 100% power operation condition. Based on the computer code, the S-CO2 Brayton cycle energy conversion system was constructed for the KALIMER-600. Using the developed turbomachinery models, the off-design characteristics and the sensitivities of the S-CO2 turbomachinery were investigated. For the development of PCHE models, a one-dimensional analysis computer code was developed to evaluate the performance of the PCHE. Possible control schemes for power control in the KALIMER-600 S-CO2 Brayton cycle were investigated by using the MARS code. Simple power reduction and recovery event was selected and analyzed for the transient calculation. For the evaluation of Na/CO2 boundary failure event, a computer was developed to simulate the complex thermodynamic behaviors coupled with the chemical reaction between liquid sodium and CO2 gas. The long term behavior of a Na/CO2 boundary failure event and its consequences which lead to a system pressure transient were evaluated

  9. Supercritical Carbon Dioxide Brayton Cycle Energy Conversion System

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jae Eun; Kim, S. O.; Seong, S. H.; Eoh, J. H.; Lee, T. H.; Choi, S. K.; Han, J. W.; Bae, S. W

    2007-12-15

    This report contains the description of the S-CO{sub 2} Brayton cycle coupled to KALIMER-600 as an alternative energy conversion system. For system development, a computer code was developed to calculate heat balance of 100% power operation condition. Based on the computer code, the S-CO{sub 2} Brayton cycle energy conversion system was constructed for the KALIMER-600. Using the developed turbomachinery models, the off-design characteristics and the sensitivities of the S-CO{sub 2} turbomachinery were investigated. For the development of PCHE models, a one-dimensional analysis computer code was developed to evaluate the performance of the PCHE. Possible control schemes for power control in the KALIMER-600 S-CO{sub 2} Brayton cycle were investigated by using the MARS code. Simple power reduction and recovery event was selected and analyzed for the transient calculation. For the evaluation of Na/CO{sub 2} boundary failure event, a computer was developed to simulate the complex thermodynamic behaviors coupled with the chemical reaction between liquid sodium and CO{sub 2} gas. The long term behavior of a Na/CO{sub 2} boundary failure event and its consequences which lead to a system pressure transient were evaluated.

  10. Thermo-economic performance of HTGR Brayton power cycles

    International Nuclear Information System (INIS)

    High temperature reached in High and Very High Temperature Reactors (VHTRs) results in thermal efficiencies substantially higher than those of actual nuclear power plants. A number of studies mainly driven by achieving optimum thermal performance have explored several layout. However, economic assessments of cycle power configurations for innovative systems, although necessarily uncertain at this time, may bring valuable information in relative terms concerning power cycle optimization. This paper investigates the thermal and economic performance direct Brayton cycles. Based on the available parameters and settings of different designs of HTGR power plants (GTHTR-300 and PBMR) and using the first and second laws of thermodynamics, the effects of compressor inter-cooling and of the compressor-turbine arrangement (i.e., single vs. multiple axes) on thermal efficiency have been estimated. The economic analysis has been based on the El-Sayed methodology and on the indirect derivation of the reactor capital investment. The results of the study suggest that a 1-axis inter-cooled power cycle has a similar thermal performance to the 3-axes one (around 50%) and, what's more, it is substantially less taxed. A sensitivity study allowed assessing the potential impact of optimizing several variables on cycle performance. Further than that, the cycle components costs have been estimated and compared. (authors)

  11. Reactor dynamics and stability analysis of a burst-mode gas core reactor, Brayton cycle space power system

    International Nuclear Information System (INIS)

    Reactor dynamics and system stability studies are performed on a conceptual burst-mode gaseous core reactor space nuclear power system. This concept operates on a closed Brayton cycle in the burst mode (on the order of 100-MW output for a few thousand seconds) using a disk magnetohydrodynamic generator for energy conversion. The fuel is a gaseous mixture of UF4 or UF6 and helium. Nonlinear dynamic analysis is performed using circulating-fuel, point-reactor-kinetics equations along with thermodynamic, lumped-parameter heat transfer and one-dimensional isentropic flow equations. The gaseous nature of the fuel plus the fact that the fuel is circulating lead to dynamic behavior that is quite different from that of conventional solid-core systems. For the transients examined, Doppler fuel temperature and moderator temperature feedbacks are insignificant when compared with reactivity feedback associated with fuel gas density variations. The gaseous fuel density power coefficient of reactivity is capable of rapidly stabilizing the system, within a few seconds, even when large positive reactivity insertions are imposed; however, because of the strength of this feedback, standard external reactivity insertions alone are inadequate to bring about significant power level changes during normal reactor operation. Additional methods of reactivity control, such as changes in the gaseous of fuel mass flow rate or core inlet pressure, are required to achieve desired power level control. Finally, linear stability analysis gives results that are qualitatively in agreement with the nonlinear analysis

  12. Examination of the performance of an unconventional combination of Rankine, Brayton, and Inverse Brayton cycles

    Energy Technology Data Exchange (ETDEWEB)

    Alabdoadaim, M.; Agnew, B.; Potts, I. [University of Newcastle-upon-Tyne (United Kingdom). School of Mechanics and Systems Engineering

    2006-07-01

    The study presented in this article examined the thermodynamic performance of a proposed system constructed from Brayton, inverse Brayton, and steam Rankine cycles. The theoretical examination was performed by varying the Brayton cycle pressure ratio for different values of inlet pressure and expansion pressures of the inverse Brayton cycle and for different ratios of the inverse Brayton power turbine mass flow to the gas generator mass flow. The results indicated that for the three values of mass flow ratio examined, better performance could be achieved when the proposed system is operated at high Brayton cycle pressure ratio (high maximum system temperature and the highest value of inverse Brayton cycle expansion pressure). It was revealed that in the case of the mass flow equal to 0.25, the proposed system achieved the highest value of Brayton cycle pressure ratio and attained a maximum thermal efficiency of 57.7 per cent. (author)

  13. Closed Brayton Cycle Power Conversion Unit for Fission Surface Power Phase I Final Report

    Science.gov (United States)

    Fuller, Robert L.

    2010-01-01

    A Closed Brayton cycle power conversion system has been developed to support the NASA fission surface power program. The goal is to provide electricity from a small nuclear reactor heat source for surface power production for lunar and Mars environments. The selected media for a heat source is NaK 78 with water as a cooling source. The closed Brayton cycle power was selected to be 12 kWe output from the generator terminals. A heat source NaK temperature of 850 K plus or minus 25 K was selected. The cold source water was selected at 375 K plus or minus 25 K. A vacuum radiation environment of 200 K is specified for environmental operation. The major components of the system are the power converter, the power controller, and the top level data acquisition and control unit. The power converter with associated sensors resides in the vacuum radiation environment. The power controller and data acquisition system reside in an ambient laboratory environment. Signals and power are supplied across the pressure boundary electrically with hermetic connectors installed on the vacuum vessel. System level analyses were performed on working fluids, cycle design parameters, heater and cooling temperatures, and heat exchanger options that best meet the needs of the power converter specification. The goal is to provide a cost effective system that has high thermal-to-electric efficiency in a compact, lightweight package.

  14. Preliminary design of the supercritical CO2 Brayton cycle energy conversion system

    International Nuclear Information System (INIS)

    The supercritical CO2 Brayton cycle energy conversion system is presented as a promising alternative to the present Rankine cycle. The principal advantage of the S-CO2 gas is a good efficiency at a modest temperature and a compact size of its components. The S-CO2 Brayton cycle coupled to a SFR also excludes the possibilities of a SWR (Sodium-Water Reaction) which is a major safety-related event, so that the safety of a SFR can be improved. KAERI is conducting a feasibility study for the supercritical carbon dioxide (S-CO2) Brayton cycle power conversion system coupled to KALIMER(Korea Advanced LIquid MEtal Reactor). The purpose of this research is to develop S-CO2 Brayton cycle energy conversion systems and evaluate their performance when they are coupled to advanced nuclear reactor concepts of the type under investigation in the Generation IV Nuclear Energy Systems. This paper contains the research overview of the S-CO2 Brayton cycle coupled to KALIMER-600 as an alternative energy conversion system

  15. Neon turbo-Brayton cycle refrigerator for HTS power machines

    Science.gov (United States)

    Hirai, Hirokazu; Hirokawa, M.; Yoshida, Shigeru; Nara, N.; Ozaki, S.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

    2012-06-01

    We developed a prototype turbo-Brayton refrigerator whose working fluid is neon gas. The refrigerator is designed for a HTS (High Temperature Superconducting) power transformer and its cooling power is more than 2 kW at 65 K. The refrigerator has a turboexpander and a turbo-compressor, which utilize magnetic bearings. These rotational machines have no rubbing parts and no oil-components. Those make a long maintenance interval of the refrigerator. The refrigerator is very compact because our newly developed turbo-compressor is volumetrically smaller than a displacement type compressor in same operating specification. Another feature of the refrigerator is a wide range operation capability for various heat-loads. Cooling power is controlled by the input-power of the turbo-compressor instead of the conventional method of using an electric heater. The rotational speed of the compressor motor is adjusted by an inverter. This system is expected to be more efficient. We show design details, specification and cooling test results of the new refrigerator in this paper.

  16. Closed Brayton cycle power system with a high temperature pellet bed reactor heat source for NEP applications

    International Nuclear Information System (INIS)

    Capitalizing on past and future development of high temperature gas reactor (HTGR) technology, a low mass 15 MWe closed gas turbine cycle power system using a pellet bed reactor heating helium working fluid is proposed for Nuclear Electric Propulsion (NEP) applications. Although the design of this directly coupled system architecture, comprising the reactor/power system/space radiator subsystems, is presented in conceptual form, sufficient detail is included to permit an assessment of overall system performance and mass. Furthermore, an attempt is made to show how tailoring of the main subsystem design characteristics can be utilized to achieve synergistic system level advantages that can lead to improved reliability and enhanced system life while reducing the number of parasitic load driven peripheral subsystems

  17. System design specification Brayton Isotope Power System (BIPS) Flight System (FS), and Ground Demonstration System (GDS)

    Energy Technology Data Exchange (ETDEWEB)

    1976-06-14

    The system design specification for ground demonstration, development, and flight qualification of a Brayton Isotope Power System (BIPS) is presented. The requirements for both a BIPS conceptual Flight System (FS) and a Ground Demonstration System (GDS) are defined.

  18. System design specification Brayton Isotope Power System (BIPS) Flight System (FS), and Ground Demonstration System (GDS)

    International Nuclear Information System (INIS)

    The system design specification for ground demonstration, development, and flight qualification of a Brayton Isotope Power System (BIPS) is presented. The requirements for both a BIPS conceptual Flight System (FS) and a Ground Demonstration System (GDS) are defined

  19. Brayton isotope power system. Volume II. System evaluation attributes

    Energy Technology Data Exchange (ETDEWEB)

    1978-03-15

    This volume of the Brayton Isotope Power System, Phase II Plan, contains the self-evaluation by AiResearch, GE, and TECO, addressing Section 3 of The Dynamic Systems Evaluation Criteria and Procedures established by the Department of Energy. These evaluation criteria addresses: Component Feasibility; Flight System Design Performance; GDS Test Results; Reliability and Practicality; Safety; Spacecraft Integration; and Cost and Risk. Included in each of these general categories are several attributes, each of which addresses a separate component, feature, or area of interest related to the power system, its development status, degree of preparedness for proceeding into a flight program, and/or the contractors' performance during Phase I. The key elements which indicate the readiness of a radioisotope power system to progress into a flight qualification program are: an advanced state of development of the power conversion system; demonstrated or exhibited potential for space systems standards of reliability; evident capability of meeting system safety requirements; favorable cost/benefit tradeoff considering projected missions and technology advancement potential; and proven feasibility of fabricating and qualifying a flight system and integrating it with a candidate spacecraft and launch vehicle. As a result of considerable government investment in Brayton system component development, the MHW isotope heat source and the BIPS Phase I Ground Demonstration System, the BIPS is a more advanced state of development than any previous radioisotope power system technology. Evidence of this is presented along with a complete review of the attributes, the contractor recommended ratings, and the rationale for the self-evaluation.

  20. Supercritical CO2 Brayton Cycle Energy Conversion System Coupled with SFR

    International Nuclear Information System (INIS)

    This report contains the description of the S-CO2 Brayton cycle coupled to KALIMER-600 as an alternative energy conversion system. For a system development, a computer code was developed to calculate heat balance of normal operation condition. Based on the computer code, the S-CO2 Brayton cycle energy conversion system was constructed for the KALIMER-600. Computer codes were developed to analysis for the S-CO2 turbomachinery. Based on the design codes, the design parameters were prepared to configure the KALIMER-600 S-CO2 turbomachinery models. A one-dimensional analysis computer code was developed to evaluate the performance of the previous PCHE heat exchangers and a design data for the typical type PCHE was produced. In parallel with the PCHE-type heat exchanger design, an airfoil shape fin PCHE heat exchanger was newly designed. The new design concept was evaluated by three-dimensional CFD analyses. Possible control schemes for power control in the KALIMER-600 S-CO2 Brayton cycle were investigated by using the MARS code. The MMS-LMR code was also developed to analyze the transient phenomena in a SFR with a supercritical CO2 Brayton cycle to develop the control logic. Simple power reduction and recovery event was selected and analyzed for the transient calculation. For the evaluation of Na-CO2 boundary failure event, a computer was developed to simulate the complex thermodynamic behaviors coupled with the chemical reaction between liquid sodium and CO2 gas. The long term behavior of a Na-CO2 boundary failure event and its consequences which lead to a system pressure transient were evaluated

  1. Brayton cycle conversion system and temperature conditioning of small space nuclear reactors

    International Nuclear Information System (INIS)

    A companion paper (Carre et al. 1989) presented at this symposium gives an overview of the French preliminary studies on space nuclear power systems in progress within the framework of a three-year (1986-1989) program. Other papers (Proust et al. 1988, Tilliette et al. 1988, Tilliette IECEC 1988) supplement the information on this activity. Low power levels of about 20-KWe and both liquid metal- and gas-cooled reactors are concerned. The Brayton cycle is currently selected as the conversion subsystem. Critical issues like safety, reliability, radiation shielding and reactor concept and technology have to be addressed more and more carefully and relevant temperature conditions are crucial. It is shown in this paper that the Brayton cycle can offer a valuable flexibility which allows the desired thermal environment. For instance, it is possible to significantly decrease the reactor inlet temperature and consequently, also given an adequate design, to favourably put forward convenient solutions for the lateral and axial bottom reflector, the shadow shield, the control drums drives and safety rods actuators and penetrations as well as for the possibility of using efficient moderator materials like metal hydrides (ZrH or 7LiH), which is worth being investigated as far as low power levels are concerned. Examples of Brayton cycle conversion subsystems and possible reactor arrangements are presented for both gas-cooled and liquid metal (NaK or Na)-cooled reactor heat sources. The study follows up the research described by Thilliette (1988, IECEC)

  2. Thermal analysis on N2 and S-CO2 Brayton cycle for the energy conversion system of small scale ultra-long cycle fast reactor

    International Nuclear Information System (INIS)

    An ultra-long cycle fast reactor (UCFR) is one of the SFR designs operating in a long cycle without refueling. The operational mechanism of long cycle fast reactor is once-through fuel cycle through breed and burn system. The benefits of long cycle fast reactor include capital/operation cost reductions, low proliferation risk, and the interim storage of light water reactor (LWR) spent fuel. For the power conversion system of next generation nuclear reactor, Brayton cycle has been mainly considered. Brayton cycle not only increases overall thermal efficiency in corresponding temperature range of GenIV reactors, but also solves sodium-water reaction issues. As a working fluid in Brayton cycle, many inactive gases are selected. For the power conversion system of next generation nuclear reactor, Brayton cycle has been mainly considered. Among the candidates for working fluid in Brayton power cycle, S-CO2 and N2 are analyzed in thermal aspect. For the major parameters including maximum system pressure, isentropic efficiencies of compressor and turbine, and pinch point, S-CO2 cycle shows the highest thermal performance. However, N2 cycle without intermediate loop gives comparable thermal performance, if high pressure around 70 bar and high isentropic efficiency of each component are maintained

  3. State space model extraction of thermohydraulic systems – Part II: A linear graph approach applied to a Brayton cycle-based power conversion unit

    International Nuclear Information System (INIS)

    This second paper in a two part series presents the application of a developed state space model extraction methodology applied to a Brayton cycle-based PCU (power conversion unit) of a PBMR (pebble bed modular reactor). The goal is to investigate if the state space extraction methodology can cope with larger and more complex thermohydraulic systems. In Part I the state space model extraction methodology for the purpose of control was described in detail and a state space representation was extracted for a U-tube system to illustrate the concept. In this paper a 25th order nonlinear state space representation in terms of the different energy domains is extracted. This state space representation is solved and the responses of a number of important states are compared with results obtained from a PBMR PCU Flownex® model. Flownex® is a validated thermo fluid simulation software package. The results show that the state space model closely resembles the dynamics of the PBMR PCU. This kind of model may be used for nonlinear MIMO (multi-input, multi-output) type of control strategies. However, there is still a need for linear state space models since many control system design and analysis techniques require a linear state space model. This issue is also addressed in this paper by showing how a linear state space model can be derived from the extracted nonlinear state space model. The linearised state space model is also validated by comparing the state space model to an existing linear Simulink® model of the PBMR PCU system. - Highlights: • State space model extraction of a pebble bed modular reactor PCU (power conversion unit). • A 25th order nonlinear time varying state space model is obtained. • Linearisation of a nonlinear state space model for use in power output control. • Non-minimum phase characteristic that is challenging in terms of control. • Models derived are useful for MIMO control strategies

  4. Thermal hydraulic feasibility of supercritical carbon dioxide Brayton cycle power conversion for the KALIMER-150 sodium-cooled fast reactor

    International Nuclear Information System (INIS)

    One possible approach to achieving a significant reduction in the overnight and operating costs of a sodium-cooled fast reactor is to replace the traditional Rankine steam cycle with an advanced power converter that consists of a gas turbine Brayton cycle that utilizes supercritical carbon dioxide (S-CO2) as the working fluid. A joint project between Argonne National Laboratory and the Korea Atomic Energy Research Institute has been initiated to investigate the thermal-hydraulic feasibility of coupling the S-CO2 Brayton cycle to the KALIMAR-150 sodium-cooled fast reactor conceptual design. As an initial step in investigating the system aspects of coupling the reactor to the S-CO2 Brayton cycle, the case is investigated in which the intermediate heat transfer loop is eliminated in order to achieve additional cost reductions. The main objectives are to determine the potential gain in plant efficiency and to estimate the size of the key Brayton cycle components. A S-CO2 Brayton cycle efficiency of 43.2% is calculated. Accounting for primary pump power and other in-house loads, a net plant efficiency of 40.8% is obtained, compared to 38.2% for the current (Rankine cycle) plant. If higher Na temperatures could be accommodated, then a 1% gain in plant efficiency could be obtained for each 20degC incremental increase in sodium core outlet temperature. Further investigation of the thermal sizing of the Na/S-Co2 heat exchanger is also carried out; parametric sensitivity studies are performed for the case in which the intermediate heat transport system is retained as well as the case in which it is eliminated. (author)

  5. Experimental and Analytical Performance of a Dual Brayton Power Conversion System

    Science.gov (United States)

    Lavelle, Thomas A.; Hervol, David S.; Briggs, Maxwell; Owen, A. Karl

    2009-01-01

    The interactions between two closed Brayton cycle (CBC) power conversion units (PCU) which share a common gas inventory and heat source have been studied experimentally using the Dual Brayton Power Conversion System (DBPCS) and analytically using the Closed- Cycle System Simulation (CCSS) computer code. Selected operating modes include steady-state operation at equal and unequal shaft speeds and various start-up scenarios. Equal shaft speed steady-state tests were conducted for heater exit temperatures of 840 to 950 K and speeds of 50 to 90 krpm, providing a system performance map. Unequal shaft speed steady-state testing over the same operating conditions shows that the power produced by each Brayton is sensitive to the operating conditions of the other due to redistribution of gas inventory. Startup scenarios show that starting the engines one at a time can dramatically reduce the required motoring energy. Although the DBPCS is not considered a flight-like system, these insights, as well as the operational experience gained from operating and modeling this system provide valuable information for the future development of Brayton systems.

  6. Preliminary design review: Brayton Isotope Power System

    International Nuclear Information System (INIS)

    The design aspects covered include flight system design, design criteria/margins/reliability, GDS design, system analysis, materials, system assembly procedure, and government furnished equipment-BTPS

  7. Enhanced arrangement for recuperators in supercritical CO2 Brayton power cycle for energy conversion in fusion reactors

    International Nuclear Information System (INIS)

    Highlights: •We propose an enhanced power conversion system layout for a Model C fusion reactor. •Proposed layout is based on a modified recompression supercritical CO2 Brayton cycle. •New arrangement in recuperators regards to classical cycle is used. •High efficiency is achieved, comparable with the best obtained in complex solutions. -- Abstract: A domestic research program called TECNOFUS was launched in Spain in 2009 to support technological developments related to a dual coolant breeding blanket concept for fusion reactors. This concept of blanket uses Helium (300 °C/400 °C) to cool part of it and a liquid metal (480 °C/700 °C) to cool the rest; it also includes high temperature (700 °C/800 °C) and medium temperature (566 °C/700 °C) Helium cooling circuits for divertor. This paper proposes a new layout of the classical recompression supercritical CO2 Brayton cycle which replaces one of the recuperators (the one with the highest temperature) by another which by-passes the low temperature blanket source. This arrangement allows reaching high turbine inlet temperatures (around 600 °C) with medium pressures (around 225 bar) and achieving high cycle efficiencies (close to 46.5%). So, the proposed cycle reveals as a promising design because it integrates all the available thermal sources in a compact layout achieving high efficiencies with the usual parameters prescribed in classical recompression supercritical CO2 Brayton cycles

  8. Nuclear Air-Brayton Combined Cycle Power Conversion Design, Physical Performance Estimation and Economic Assessment

    Science.gov (United States)

    Andreades, Charalampos

    The combination of an increased demand for electricity for economic development in parallel with the widespread push for adoption of renewable energy sources and the trend toward liberalized markets has placed a tremendous amount of stress on generators, system operators, and consumers. Non-guaranteed cost recovery, intermittent capacity, and highly volatile market prices are all part of new electricity grids. In order to try and remediate some of these effects, this dissertation proposes and studies the design and performance, both physical and economic, of a novel power conversion system, the Nuclear Air-Brayton Combined Cycle (NACC). The NACC is a power conversion system that takes a conventional industrial frame type gas turbine, modifies it to accept external nuclear heat at 670°C, while also maintaining its ability to co-fire with natural gas to increase temperature and power output at a very quick ramp rate. The NACC addresses the above issues by allowing the generator to gain extra revenue through the provision of ancillary services in addition to energy payments, the grid operator to have a highly flexible source of capacity to back up intermittent renewable energy sources, and the consumer to possibly see less volatile electricity prices and a reduced probability of black/brown outs. This dissertation is split into six sections that delve into specific design and economic issues related to the NACC. The first section describes the basic design and modifications necessary to create a functional externally heated gas turbine, sets a baseline design based upon the GE 7FB, and estimates its physical performance under nominal conditions. The second section explores the off-nominal performance of the NACC and characterizes its startup and shutdown sequences, along with some of its safety measures. The third section deals with the power ramp rate estimation of the NACC, a key performance parameter in a renewable-heavy grid that needs flexible capacity. The

  9. A parametric study of motor starting for a 2- to 10-kilowatt Brayton power system

    Science.gov (United States)

    Cantoni, D. A.

    1971-01-01

    A study of the motor starting of a Brayton cycle power system was conducted to provide estimates of system sensitivity to several controllable parameters. These sensitivity estimates were used as a basis for selection of an optimum motor-start scheme to be implemented on the 2- to 10-kilowatt Brayton power system designed and presently under test. The studies were conducted with an analog simulation of the Brayton power system and covered a range of frequencies from 400 Hz (33 percent design) to 1200 Hz (design), voltage-to-frequency ratios of 0.050 (50 percent design) to 0.100 (design), turbine-inlet temperatures of 800 K (1440 R, 70 percent design) to 1140 K (2060 deg R, design), and prestart pressure levels of 14.5 psia to 29.0 psia. These studies have shown the effect of selected system variables on motor starting. The final selection of motor-start variables can therefore be made on the basis of motor-start inverter complexity, battery size and weight, desired steady-state pressure level after startup, and other operational limitations. In general, the study showed the time required for motor starting to be inversely proportional to motor frequency, voltage, turbine-inlet temperature, and pressure level. An increase in any of these parameters decreases startup time.

  10. Brayton isotope power system. Phase I (Ground demonstration system) configuration control document (CCD)

    Energy Technology Data Exchange (ETDEWEB)

    1975-09-25

    The Brayton Isotope Power System (BIPS) Ground Demonstration System (GDS) configuration is defined. The GDS is configured to be similar to a conceptual flight system design referred to herein as the BIPS Flight System (FS). The Brayton Isotope Power System is being developed by the ERDA as a 500 to 2000 W/sub e/, 7 year life 3.5 W/sub e/ per pound space power system. The system was a closed Brayton dynamic system to convert energy from an isotope heat source at a net efficiency exceeding 25%. This CCD is for the first phase of the ERDA program to have a qualified system ready for launch by June 30, 1981. Phase I is a 36 month effort to provide a conceptual design of the flight system and design, fabricate and test a ground demonstration system. The baseline system is predicated on using two of the multihundred-watt isotope heat sources being developed for the ERDA by GE. The Ground Demonstration System will simulate, as closely as possible, the Brayton Isotope Power Flight System and will utilize components and technology being developed by NASA for the Mini-Brayton rotating unit (AIRPHX), recuperator (AIRLA) and heat source assembly (GE). The Ground Demonstration System includes a performance test and a 1000-hour endurance test.

  11. Compressor and Turbine Models of Brayton Units for Space Nuclear Power Systems

    Science.gov (United States)

    Gallo, Bruno M.; El-Genk, Mohamed S.; Tournier, Jean-Michel

    2007-01-01

    Closed Brayton Cycles with centrifugal flow, single-shaft turbo-machines are being considered, with gas cooled nuclear reactors, to provide 10's to 100's of electrical power to support future space exploration missions and Lunar and Mars outposts. Such power system analysis is typically based on the cycle thermodynamics, for given operating pressures and temperatures and assumed polytropic efficiencies of the compressor and turbine of the Brayton energy conversion units. Thus the analysis results not suitable for modeling operation transients such as startup and changes in the electric load. To simulate these transients, accurate models of the turbine and compressor in the Brayton rotating unit, which calculate the changes in the compressor and turbine efficiencies with system operation are needed. This paper presents flow models that account for the design and dimensions of the compressor impeller and diffuser, and the turbine stator and rotor blades. These models calculate the various enthalpy losses and the polytropic efficiencies along with the pressure ratios of the turbine and compressor. The predictions of these models compare well with reported performance data of actual hardware. In addition, the results of a parametric analysis to map the operations of the compressor and turbine, as functions of the rotating shaft speed and inlet Mach number of the gas working fluid, are presented and discussed. The analysis used a binary mixture of He-Xe with a molecular weight of 40 g/mole as the working fluid.

  12. Brayton-Cycle Heat Recovery System Characterization Program. Glass-furnace facility test plan

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-29

    The test plan for development of a system to recover waste heat and produce electricity and preheated combustion air from the exhaust gases of an industrial glass furnace is described. The approach is to use a subatmospheric turbocompressor in a Brayton-cycle system. The operational furnace test requirements, the operational furnace environment, and the facility design approach are discussed. (MCW)

  13. Phase I: controls preliminary design report for Brayton Isotope Power System (BIPS)

    International Nuclear Information System (INIS)

    Background analyses of three control systems capable of controlling the speed, output voltage, and start rate of Brayton Isotope Power Systems (BIPS) are presented. Conclusions of all functions considered are summarized

  14. Phase I: controls preliminary design report for Brayton Isotope Power System (BIPS)

    Energy Technology Data Exchange (ETDEWEB)

    1976-08-20

    Background analyses of three control systems capable of controlling the speed, output voltage, and start rate of Brayton Isotope Power Systems (BIPS) are presented. Conclusions of all functions considered are summarized. (TFD)

  15. Reactor/Brayton power systems for nuclear electric spacecraft

    International Nuclear Information System (INIS)

    Studies are currently underway to assess the technological feasibility of a nuclear-reactor-powered spacecraft propelled by electric thrusters. The purpose of this study was to provide comparative information on a closed cycle gas turbine power conversion system

  16. Comparison of Analytical Predictions and Experimental Results for a Dual Brayton Power System (Discussion on Test Hardware and Computer Model for a Dual Brayton System)

    Science.gov (United States)

    Johnson, Paul K.

    2007-01-01

    NASA Glenn Research Center (GRC) contracted Barber-Nichols, Arvada, CO to construct a dual Brayton power conversion system for use as a hardware proof of concept and to validate results from a computational code known as the Closed Cycle System Simulation (CCSS). Initial checkout tests were performed at Barber- Nichols to ready the system for delivery to GRC. This presentation describes the system hardware components and lists the types of checkout tests performed along with a couple issues encountered while conducting the tests. A description of the CCSS model is also presented. The checkout tests did not focus on generating data, therefore, no test data or model analyses are presented.

  17. Comparison of Analytical Predictions and Experimental Results for a Dual Brayton Power System

    Science.gov (United States)

    Johnson, Paul

    2007-01-01

    NASA Glenn Research Center (GRC) contracted Barber- Nichols, Arvada, CO to construct a dual Brayton power conversion system for use as a hardware proof of concept and to validate results from a computational code known as the Closed Cycle System Simulation (CCSS). Initial checkout tests were performed at Barber- Nichols to ready the system for delivery to GRC. This presentation describes the system hardware components and lists the types of checkout tests performed along with a couple issues encountered while conducting the tests. A description of the CCSS model is also presented. The checkout tests did not focus on generating data, therefore, no test data or model analyses are presented.

  18. An isotope heat source integrated with a 7 kW/e/ to 25 kW/e/ Brayton cycle space power supply.

    Science.gov (United States)

    Ryan, R. L.; Graham, J. W.; Coombs, M. G.; Bloomfield, H. S.

    1972-01-01

    The power system described is intended for applications in a manned space mission. The Isotope Reentry Vehicle (IRV) developed is considered together with the Heat Source (HS), the Heat Source Heat Exchanger and the Brayton Cycle Power Conversion Module. Other subjects discussed include the IRV/Brayton cycle spacecraft integration concept, abort and deorbit mechanization, emergency cooling methods, and crew shielding requirements. Mounting and integration for the IRV is to a large degree controlled by nuclear safety requirements. Another major factor in the installation concept is the type of emergency cooling or passive heat dump mode used in rejection of HS energy.

  19. Brayton Power Conversion System Study to Advance Technology Readiness for Nuclear Electric Propulsion — Phase I

    Science.gov (United States)

    Frye, Patrick E.; Allen, Robert; Delventhal, Rex

    2005-02-01

    To investigate and mature space based nuclear power conversion technologies NASA awarded several contracts under Prometheus, the Nuclear Systems Program. The studies described in this paper were performed under one of those contracts, which was to investigate the use of a nuclear power conversion system based on the closed Brayton cycle (CBC). The conceptual design effort performed included BPCS (Brayton power conversion system) trade studies to minimize system weight and radiator area and advance the state of the art of BPCS technology. The primary requirements for studies were a power level of 100 kWe (to the PPU), a low overall power system mass (with a target of less than 3000 kg), and a lifetime of 15 years (10 years full power). For the radiation environment, the system was to operate in the generic space environment and withstand the extreme environments within the Jovian system. The studies defined a BPCS design traceable to NBP (Nuclear Electric Propulsion) requirements and suitable for future potential missions with a sound technology plan for TRL (Technical Readiness Level) advancement identified. The studies assumed a turbine inlet temperature ˜ 100C above the current the state of the art capabilities with materials issues identified and an approach for resolution developed. Analyses and evaluations of six HRS (heat rejection subsystem) concepts and PMAD (Power Management and Distribution) architecture trades will be discussed in the paper.

  20. Thermodynamic Optimization of Supercritical CO2 Brayton Cycles

    International Nuclear Information System (INIS)

    The supercritical CO2 Brayton cycle has been studied for nuclear applications, mainly for one of the alternative power conversion systems of the sodium cooled fast reactor, since 1960's. Although the supercritical CO2 Brayton cycle has not been expected to show higher efficiency at lower turbine inlet temperature over the conventional steam Rankine cycle, the higher density of supercritical CO2 like a liquid in the supercritical region could reduce turbo-machinery sizes, and the potential problem of sodium-water reaction with the sodium cooled fast reactor might be solved with the use of CO2 instead of water. The supercritical CO2 recompression Brayton cycle was proposed for the better thermodynamic efficiency than for the simple supercritical CO2 Brayton cycle. Thus this paper presents the efficiencies of the supercritical CO2 recompression Brayton cycle along with several decision variables for the thermodynamic optimization of the supercritical CO2 recompression Brayton cycle. The analytic results in this study show that the system efficiency reaches its maximum value at a compressor outlet pressure of 200 bars and a recycle fraction of 30 %, and the lower minimum temperature approach at the two heat exchangers shows higher system efficiency as expected

  1. Thermodynamic Optimization of Supercritical CO{sub 2} Brayton Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Rhim, Dong-Ryul; Park, Sung-Ho; Kim, Su-Hyun; Yeom, Choong-Sub [Institute for Advanced Engineering, Yongin (Korea, Republic of)

    2015-05-15

    The supercritical CO{sub 2} Brayton cycle has been studied for nuclear applications, mainly for one of the alternative power conversion systems of the sodium cooled fast reactor, since 1960's. Although the supercritical CO{sub 2} Brayton cycle has not been expected to show higher efficiency at lower turbine inlet temperature over the conventional steam Rankine cycle, the higher density of supercritical CO{sub 2} like a liquid in the supercritical region could reduce turbo-machinery sizes, and the potential problem of sodium-water reaction with the sodium cooled fast reactor might be solved with the use of CO{sub 2} instead of water. The supercritical CO{sub 2} recompression Brayton cycle was proposed for the better thermodynamic efficiency than for the simple supercritical CO{sub 2} Brayton cycle. Thus this paper presents the efficiencies of the supercritical CO{sub 2} recompression Brayton cycle along with several decision variables for the thermodynamic optimization of the supercritical CO{sub 2} recompression Brayton cycle. The analytic results in this study show that the system efficiency reaches its maximum value at a compressor outlet pressure of 200 bars and a recycle fraction of 30 %, and the lower minimum temperature approach at the two heat exchangers shows higher system efficiency as expected.

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

    Science.gov (United States)

    Jaffe, Leonard D.

    1988-01-01

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

  3. Transient analysis of an FHR coupled to a helium Brayton power cycle

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Minghui [The Ohio State Univ., Columbus, OH (United States). Nuclear Engineering Program; Kim, In Hun [The Ohio State Univ., Columbus, OH (United States). Nuclear Engineering Program; Sun, Xiaodong [The Ohio State Univ., Columbus, OH (United States). Nuclear Engineering Program; Christensen, Richard [The Ohio State Univ., Columbus, OH (United States). Nuclear Engineering Program; Utgikar, Vivek [Univ. of Idaho, Idaho Falls, ID (United States); Sabharwall, Piyush [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    The Fluoride salt-cooled High-temperature Reactor (FHR) features a passive decay heat removal system and a high-efficiency Brayton cycle for electricity generation. It typically employs an intermediate loop, consisting of an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX), to couple the primary system with the power conversion unit (PCU). In this study, a preliminary dynamic system model is developed to simulate transient characteristics of a prototypic 20-MWth Fluoride salt-cooled High-temperature Test Reactor (FHTR). The model consists of a series of differential conservation equations that are numerically solved using the MATLAB platform. For the reactor, a point neutron kinetics model is adopted. For the IHX and SHX, a fluted tube heat exchanger and an offset strip-fin heat exchanger are selected, respectively. Detailed geometric parameters of each component in the FHTR are determined based on the FHTR nominal steady-state operating conditions. Three initiating events are simulated in this study, including a positive reactivity insertion, a step increase in the mass flow rate of the PCU helium flow, and a step increase in the PCU helium inlet temperature to the SHX. The simulation results show that the reactor has inherent safety features for those three simulated scenarios. It is observed that the increase in the temperatures of the fuel pebbles and primary coolant is mitigated by the decrease in the reactor power due to negative temperature feedbacks. The results also indicate that the intermediate loop with the two heat exchangers plays a significant role in the transient progression of the integral reactor system.

  4. Brayton Isotope Power System. Phase I. (Ground demonstration system) Configuration Control Document (CCD)

    International Nuclear Information System (INIS)

    The configuration control document (CCD) defines the BIPS-GDS configuration. The GDS configuration is similar to a conceptual flight system design, referred to as the BIPS-FS, which is discussed in App. I. The BIPS is being developed by ERDA as a 500 to 2000 W(e), 7-y life, space power system utilizing a closed Brayton cycle gas turbine engine to convert thermal energy (from an isotope heat source) to electrical energy at a net efficiency exceeding 25 percent. The CCD relates to Phase I of an ERDA Program to qualify a dynamic system for launch in the early 1980's. Phase I is a 35-month effort to provide an FS conceptual design and GDS design, fabrication, and test. The baseline is a 7-year life, 450-pound, 4800 W(t), 1300 W(e) system which will use two multihundred watt (MHW) isotope heat sources being developed

  5. Brayton Isotope Power System. Phase I. (Ground demonstration system) Configuration Control Document (CCD)

    Energy Technology Data Exchange (ETDEWEB)

    1976-03-15

    The configuration control document (CCD) defines the BIPS-GDS configuration. The GDS configuration is similar to a conceptual flight system design, referred to as the BIPS-FS, which is discussed in App. I. The BIPS is being developed by ERDA as a 500 to 2000 W(e), 7-y life, space power system utilizing a closed Brayton cycle gas turbine engine to convert thermal energy (from an isotope heat source) to electrical energy at a net efficiency exceeding 25 percent. The CCD relates to Phase I of an ERDA Program to qualify a dynamic system for launch in the early 1980's. Phase I is a 35-month effort to provide an FS conceptual design and GDS design, fabrication, and test. The baseline is a 7-year life, 450-pound, 4800 W(t), 1300 W(e) system which will use two multihundred watt (MHW) isotope heat sources being developed.

  6. Preliminary Failure Modes, Effects and Criticality Analysis (FMECA) of the conceptual Brayton Isotope Power System (BIPS) Flight System

    International Nuclear Information System (INIS)

    A failure modes, effects and criticality analysis (FMECA) was made of the Brayton Isotope Power System Flight System (BIPS-FS) as presently conceived. The components analyzed include: Mini-BRU; Heat Source Assembly (HSA); Mini-Brayton Recuperator (MBR); Space Radiator; Ducts and Bellows, Insulation System; Controls; and Isotope Heat Source (IHS)

  7. Specification requirements summary for the Brayton Isotope Power System (BIPS) Ground Demonstration System (GDS)

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, E.E.

    1976-02-10

    This document provides a summary of the required program specifications and procedures for the ERDA Phase I Brayton Isotope Power System (BIPS) Program. Also included are document definitions, descriptions, and formats, and a listing of commonly used abbreviations. This document is intended to be used as a guide in document preparation and control.

  8. Binary Brayton cycle with two isothermal processes

    International Nuclear Information System (INIS)

    Highlights: • This paper presents binary Brayton cycle with two isothermal processes. • Different parameters affecting the cycle performance have been studied. • The present cycle is a promising cycle for future power generation. - Abstract: The literature introduced isothermal concept and binary Brayton cycle as two promising methods used to enhance the performance of the gas turbine. Consequently, this work presents a cycle based on the blending of the two methods. This cycle is composed of gas turbine topping cycle with isothermal combustion and air turbine bottoming cycle with isothermal heating. Different parameters affecting the cycle performance have been studied. Simulations demonstrate that the present cycle achieves drastic enhancement in performance. The cycle merits justify its potential utilization for future power generation

  9. Simulation of CO2 Brayton Cycle for Engine Exhaust Heat Recovery under Various Operating Loads

    Institute of Scientific and Technical Information of China (English)

    舒歌群; 张承宇; 田华; 高媛媛; 李团兵; 仇荣赓

    2015-01-01

    A bottoming cycle system based on CO2 Brayton cycle is proposed to recover the engine exhaust heat. Its performance is compared with the conventional air Brayton cycle under five typical engine conditions. The results show that CO2 Brayton cycle proves to be superior to the air Brayton cycle in terms of the system net output power, thermal efficiency and recovery efficiency. In most cases, the recovery efficiency of CO2 Brayton cycle can be higher than 9%and the system has a better performance at the engine’s high operating load. The thermal efficiency can be as large as 24.83%under 100%operating load, accordingly, the net output power of 14.86 kW is obtained.

  10. Finite-thermal reservoir effects on ecologically optimized closed regenerative Joule-Brayton power cycles

    Energy Technology Data Exchange (ETDEWEB)

    Khaliq, A. [Jamia Millia Islamia, New Delhi (India). Dept. of Mechanical Engineering

    2006-07-01

    A finite-time thermodynamic analysis based on a new kind of optimization criterion has been carried out for an endoreversible and regenerative Joule-Brayton power cycle coupled with variable temperature thermal reservoirs. The optimal performance and design parameters that maximize the ecological function are investigated. In this context, the optimal temperatures of the working fluid, the optimum power output, the optimum thermal efficiency, and the optimum second-law efficiency are determined in terms of technical parameters. Results are reported for the effect of regeneration, hot-cold temperature ratio, and the number of heat transfer units in hot and cold exchangers on the optimal performance parameters. The power and efficiency at maximum ecological function are found to be less than the maximum power and Curzon-Ahlborn efficiency. Power output increases significantly with increasing hot-cold side temperature ratio. However, it slightly increased as the number of heat transfer units in the regenerator increases. The optimization of ecological function leads to the improvement in exergetic efficiency and thermal efficiency, especially for low hot-cold side temperature ratios. Moreover, the thermal efficiency at maximum ecological function is less than the average of the finite time or maximum power efficiency and reversible Carnot efficiency. (author)

  11. Cold startup and low temperature performance of the Brayton cycle electrical subsystem

    Science.gov (United States)

    Vrancik, J. E.; Bainbridge, R. C.

    1971-01-01

    Cold performance tests and startup tests were conducted on the Brayton-cycle inverter, motor-driven pump, dc supply, speed control with parasitic load resistor and the Brayton control system. These tests were performed with the components in a vacuum and mounted on coldplates. A temperature range of ?25 to -50 C was used for the tests. No failures occurred, and component performance gave no indication that there would be any problem with the safe operation of the Brayton power generating system.

  12. Preliminary market analysis for Brayton cycle heat recovery system characterization program. Subtask 5. 2 of phase I program plan

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-31

    The purpose of the task is to determine the market potential of the Brayton-cycle Subatmospheric System (SAS), especially as applied to the glass processing industry. Areas which impact the sales of the Brayton-cycle systems examined are: market size; opportunities for waste heat system installation (furnace rebuild and repair); pollution control on glass furnaces; equipment costs; equipment performance; and market growth potential. Supporting data were compiled for the glass industry inventory and are presented in Appendix A. Emission control techniques in the glass industry are discussed in Appendix B. (MCW)

  13. Assessing the potential of hybrid fossil–solar thermal plants for energy policy making: Brayton cycles

    International Nuclear Information System (INIS)

    This paper proposes a first study in-depth of solar–fossil hybridization from a general perspective. It develops a set of useful parameters for analyzing and comparing hybrid plants, it studies the case of hybridizing Brayton cycles with current solar technologies and shows a tentative extrapolation of the results to integrated combined cycle systems (ISCSS). In particular, three points have been analyzed: the technical requirements for solar technologies to be hybridized with Brayton cycles, the temperatures and pressures at which hybridization would produce maximum power per unit of fossil fuel, and their mapping to current solar technologies and Brayton cycles. Major conclusions are that a hybrid plant works in optimum conditions which are not equal to those of the solar or power blocks considered independently, and that hybridizing at the Brayton cycle of a combined cycle could be energetically advantageous. -- Highlights: •We model a generic solar–fossil hybrid Brayton cycle. •We calculate the operating conditions for maximum ratio power/fuel consumption. •Best hybrid plant conditions are not the same as solar or power blocks separately. •We study potential for hybridization with current solar technologies. •Hybridization at the Brayton in a combined cycle may achieve high power/fuel ratio

  14. Brayton isotope power system, phase I. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1978-07-28

    The Phase I program resulted in the development and ground demonstration of a dynamic power conversion system. The two key contractual objectives of 25% conversion efficiency and 1000 h of endurance testing were successfully met. As a result of the Phase I effort, the BIPS is a viable candidate for further development into a flight system capable of sustained operation in space. It represents the only known dynamic space power system to demonstrate the performance and endurance coupled with the simplicity necessary for reliable operation. This final report follows thirty-five monthly reports. For expediency, it makes liberal use of referenced documents which have been submitted to DOE during the course of the program.

  15. Sensitivity study on nitrogen Brayton cycle coupled with a small ultra-long cycle fast reactor

    International Nuclear Information System (INIS)

    The main characteristics of UCFR are constant neutron flux and power density. They move their positions every moment at constant speed along with axial position of fuel rod for 60 years. Simultaneously with the development of the reactors, a new power conversion system has been considered. To solve existing issues of vigorous sodium-water reaction in SFR with steam power cycle, many researchers suggested a closed Brayton cycle as an alternative technique for SFR power conversion system. Many inactive gases are selected as a working fluid in Brayton power cycle, mainly supercritical CO2 (S-CO2). However, S-CO2 still has potential for reaction with sodium. CO2-sodium reaction produces solid product, which has possibility to have an auto ignition reaction around 600 .deg. C. Thus, instead of S-CO2, CEA in France has developed nitrogen power cycle for ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration). In addition to inactive characteristic of nitrogen with sodium, its thermal and physical similarity with air enables to easily adopt to existing air Brayton cycle technology. In this study, for an optimized power conversion system for UCFR, a nitrogen Brayton cycle was analyzed in thermodynamic aspect. Based on subchannel analysis data of UCFR-100, a parametric study for thermal performance of nitrogen Brayton cycle was achieved. The system maximum pressure significantly affects to the overall efficiency of cycle, while other parameters show little effects. Little differences of the overall efficiencies for all cases between three stages (BOC, MOC, EOC) indicate that the power cycle of UCFR-100 maintains its performance during the operation

  16. Supercritical CO2 Brayton power cycles for DEMO fusion reactor based on Helium Cooled Lithium Lead blanket

    International Nuclear Information System (INIS)

    Fusion energy is one of the most promising solutions to the world energy supply. This paper presents an exploratory analysis of the suitability of supercritical CO2 Brayton power cycles (S-CO2) for low-temperature divertor fusion reactors cooled by helium (as defined by EFDA). Integration of three thermal sources (i.e., blanket, divertor and vacuum vessel) has been studied through proposing and analyzing a number of alternative layouts, achieving an improvement on power production higher than 5% over the baseline case, which entails to a gross efficiency (before self-consumptions) higher than 42%. In spite of this achievement, the assessment of power consumption for the circulating heat transfer fluids results in a penalty of 20% in the electricity production. Once the most suitable layout has been selected an optimization process has been conducted to adjust the key parameters to balance performance and size, achieving an electrical efficiency (electricity without taking into account auxiliary consumptions due to operation of the fusion reactor) higher than 33% and a reduction in overall size of heat exchangers of 1/3. Some relevant conclusions can be drawn from the present work: the potential of S-CO2 cycles as suitable converters of thermal energy to power in fusion reactors; the significance of a suitable integration of thermal sources to maximize power output; the high penalty of pumping power; and the convenience of identifying the key components of the layout as a way to optimize the whole cycle performance. - Highlights: • Supercritical CO2 Brayton cycles have been proposed for BoP of HCLL fusion reactor. • Low temperature sources have been successfully integrated with high temperature ones. • Optimization of thermal sources integration improves 5% the electricity production. • Assessment of pumping power with sources and sink loops results on 20% of gross power. • Matching of key parameters has conducted to 1/3 of reduction in heat exchangers

  17. Acacia: A small scale power plant with pebble bed cartridge reactor and indirect Brayton cycle

    International Nuclear Information System (INIS)

    For markets other than large-scale electricity production a 60 MWth, 23 MWe (max.) nuclear plant design with an indirect Brayton cycle is proposed for application on the short to medium term. The reactor will be cooled by helium, whereas for the secondary cycle nitrogen is proposed as a heat carrier. In this way, a conventional air based gas turbine can be applied, while at the same time excluding the scenario of air ingress in the reactor core through a heat exchanger leak. Two variations of cycle design will be discussed: co-generation and maximized electricity production. The cogeneration mode will be elaborated for the application of seawater desalination. The reactor core geometry is annular with a central graphite reflector region, creating an optimal location for burnable poison. Optimization calculations on burnable poison distribution show that burnup of fuel and poison are balancing each other into a fairly constant reactivity behaviour during the entire core lifetime. Also, the two most important safety transient scenarios for pebble bed reactors, Pressurised and Depressurised Loss Of Forced Cooling, will be discussed. It will be shown that the maximum fuel temperatures will stay below the level where fuel damage starts for any point in time. (author)

  18. Thermal Assessment of Very High Temperature Reactors: Direct and Indirect Brayton Power Cycles

    International Nuclear Information System (INIS)

    Search for a sustainable energy supply system has driven nuclear engineering towards what has been termed Generation IV. One of the main objectives of these innovative nuclear designs is to reach a high thermal efficiency in their power cycles. This way a substantial fuel saving and waste reduction is achieved, which would enhance competitiveness of the nuclear kWh. This paper investigates the thermal performance of helium-cooled power cycles based on the characteristic working parameters of Very High Temperature Reactor systems both at present and at the near future. Direct (C(IC)2HTRTX) and indirect (C(IC)2(IHX)TX) cycle baselines have been modelled and both have shown an excellent thermal performance ( with thermal efficiencies near or even higher than 50%). Enhancement of associated technology would increase thermal performance (i.e., and wnet) of both cycles drastically. The analysis of the results indicate that from the thermal performance standpoint, the cycle C(IC)2HTRTX would be a better option. However, when advances in associated technologies are considered, the efficiency gap between the two baselines analyzed become smaller. In no case net power turned out to be a differential feature between the layouts. (authors)

  19. Simulation of operational an accidental behaviour of modular high temperature reactors with Brayton cycle Power Conversion Unit

    International Nuclear Information System (INIS)

    The present work analyses and investigates the behaviour of a High Temperature Reactor (HTR) with a Pebble Bed core connected to a Brayton cycle Power Conversion Unit (PCU) during operational and accident conditions. The modelling of a complete circuit including both the PCU and the Pebble Bed Reactor has been performed with the commercial thermal-fluid analysis simulation code Flownex. Flownex has been developed for High Temperature Pebble Bed Reactor applications, and has been exten-sively validated against other codes. As the reactor core model incorporated in Flownex is a simplified model based on 0D point kinetics, the extended 1D WKIND core model was implemented in the analysis calculations using a special coupling methodology. This study introduces a new sub-routine which enables the cou-pling of the WKIND reactor core model to the Flownex PCU model via an external interface. The interface facilitates the data exchange between the two codes, allowing for necessary manipulations and synchronisation of the coupled codes. By doing so, the 1D diffusion equation solution implemented in WKIND core model replaces the point kinetics model implemented in Flownex. This replacement allows for a detailed accurate solution even for very fast transients, through the treatment of the space-dependent heat conduction from the graphite matrix to helium. Flownex component models have been validated against the experimental results of the 50 MWel direct helium turbine facility Energieversorgung Oberhausen (EVO II). This provided the opportunity to validate Flownex calculations against experimental data derived from a large-scale helium Brayton cycle installation. Small differences observed in the results could be explained. Based upon steady state and transient analysis it is concluded that Flownex models simulate accurately the behaviour of the components integrated in the EVO II plant. Such models could be applied to analyse the transient behaviour of the total system of the

  20. An Experimental Programme to Evaluate the Feasibility of Jet Compressors for Closed Brayton Cycle MPD Systems

    International Nuclear Information System (INIS)

    The application of jet compressors to closed Brayton cycle MPD systems has been suggested previously. In the present paper the feasibility of jet compression for MPD systems is investigated and some preliminary test results from a single-stage jet compressor loop are given. Thepurposeoftheexperimentalprogrammeis, (1) to simulate the operation of a jet compressor under conditions comparable to those of an actual MPD plant, and (2) to study the physics of momentum transfer of two high velocity gas (or vapour) streams of very different molecular weights. A jet compressor in which both gases mix at equal forward velocity has the same theoretical compression ratio as a reversible engine. The upper limit for the compression ratio achievable for a given set of input parameters (stagnation properties of both gases) can be calculated from purely thermodynamic principles. The expressions for the performance of an ideal jet compressor were applied to two typical high temperature MPD cycles. The overall cycle efficiency is somewhat lower than obtainable with rotating machinery, but acceptable for special applications. In the experimental programme a single-stage test facility was designed and operated. The driving gas was caesium vapour, the driven gas helium. In the design of the system the objective was to simulate the temperatures, pressures and working media of an MPD plant on a small scale. The facility is capable of handling up to 12 g/sec of the primary stream (caesium) and up to 2.5 g of the secondary stream (helium). The caesium is fed by a diaphragm pump into a refractory metal boiler at a pressure of up to 8.0 atmospheres and then superheated to approximately 1700°K. The superheated vapour expands in a supersonic nozzle and transfers part of its momentum to the low temperature helium stream. The helium is circulated in a closed loop which is equipped with a throttle valve to simulate the pressure drop which would occur in an MPD generator. During some preliminary

  1. State space model extraction of thermohydraulic systems Part II: a linear graph approach applied to a Brayton cycle–based power conversion unit

    OpenAIRE

    Uren, Kenneth Richard; Schoor, George van

    2013-01-01

    This second paper in a two part series presents the application of a developed state space model extraction methodology applied to a Brayton cycle-based PCU (power conversion unit) of a PBMR (pebble bed modular reactor). The goal is to investigate if the state space extraction methodology can cope with larger and more complex thermohydraulic systems. In Part I the state space model extraction methodology for the purpose of control was described in detail and a state space represen...

  2. Gas Foil Bearing Technology Advancements for Closed Brayton Cycle Turbines

    Science.gov (United States)

    Howard, Samuel A.; Bruckner, Robert J.; DellaCorte, Christopher; Radil, Kevin C.

    2007-01-01

    Closed Brayton Cycle (CBC) turbine systems are under consideration for future space electric power generation. CBC turbines convert thermal energy from a nuclear reactor, or other heat source, to electrical power using a closed-loop cycle. The operating fluid in the closed-loop is commonly a high pressure inert gas mixture that cannot tolerate contamination. One source of potential contamination in a system such as this is the lubricant used in the turbomachine bearings. Gas Foil Bearings (GFB) represent a bearing technology that eliminates the possibility of contamination by using the working fluid as the lubricant. Thus, foil bearings are well suited to application in space power CBC turbine systems. NASA Glenn Research Center is actively researching GFB technology for use in these CBC power turbines. A power loss model has been developed, and the effects of a very high ambient pressure, start-up torque, and misalignment, have been observed and are reported here.

  3. Back Work Ratio of Brayton Cycle

    Directory of Open Access Journals (Sweden)

    Malaver de la Fuente M.

    2010-07-01

    Full Text Available This paper analizes the existing relation between temperatures, back work ratio and net work of Brayton cycle, a cycle that describes gas turbine engines performance. The application of computational soft ware helps to show the influence of back work ratio or coupling ratio, compressor and turbine in let temperatures in an ideal thermodynamical cycle. The results lead to deduce that the maximum value reached in back work ratio will depend on the ranges of maximum and minimal temperatures of Brayton cycle.

  4. Effects of vibration and shock on the performance of gas-bearing space-power Brayton cycle turbomachinery. Part 4: Suppression of rotor-bearing system vibrations through flexible bearing support damping

    Science.gov (United States)

    Tessarzik, J. M.; Chiang, T.; Badgley, R. H.

    1974-01-01

    A bearing damper, operating on the support flexure of a pivoted pad in a tilting-pad type gas-lubricated journal bearing, has been designed, built, and tested under externally-applied random vibrations. The NASA Brayton Rotating Unit (BRU), a 36,000 rpm, 10-Kwe turbogenerator had previously been subjected in the MTI Vibration Test Laboratory to external random vibrations, and vibration response data had been recorded and analyzed for amplitude distribution and frequency content at a number of locations in the machine. Based on data from that evaluation, a piston-type damper was designed and developed for each of the two flexibly-supported journal bearing pads (one in each of the two three-pad bearings). A modified BRU, with dampers installed, has been re-tested under random vibration conditions. Root-mean-square vibration amplitudes were determined from the test data, and displacement power spectral density analyses have been performed. Results of these data reduction efforts have been compared with vibration tolerance limits. Results of the tests indicate significant reductions in vibration levels in the bearing gas-lubricant films, particularly in the rigidly-mounted pads. The utility of the gas-lubricated damper for limiting rotor-bearing system vibrations in high-speed turbomachinery has thus been demonstrated.

  5. Integrated solar thermal Brayton cycles with either one or two regenerative heat exchangers for maximum power output

    International Nuclear Information System (INIS)

    The main objective of this paper is to optimise the open-air solar-thermal Brayton cycle by considering the implementation of the second law of thermodynamics and how it relates to the design of the heat exchanging components within it. These components included one or more regenerators (in the form of cross-flow heat exchangers) and the receiver of a parabolic dish concentrator where the system heat was absorbed. The generation of entropy was considered as it was associated with the destruction of exergy or available work. The dimensions of some components were used to optimise the cycles under investigation. EGM (Entropy Generation Minimisation) was employed to optimise the system parameters by considering their influence on the total generation of entropy (destruction of exergy). Various assumptions and constraints were considered and discussed. The total entropy generation rate and irreversibilities were determined by considering the individual components and ducts of the system, as well as their respective inlet and outlet conditions. The major system parameters were evaluated as functions of the mass flow rate to allow for a proper discussion of the system performance. The performances of both systems were investigated, and characteristics were listed for both. Finally, a comparison is made to shed light on the differences in performance. - Highlights: • Implementation of the second law of thermodynamics. • Design of heat exchanging and collecting equipment. • Utilisation of Entropy Generation Minimization. • Presentation of a multi-objective optimization. • Raise efficiency with more regeneration

  6. Performance optimization of quantum Brayton refrigeration cycle working with spin systems

    International Nuclear Information System (INIS)

    The new model of a quantum refrigeration cycle composed of two adiabatic and two isomagnetic field processes is established. The working substance in the cycle consists of many non-interacting spin-1/2 systems. The performance of the cycle is investigated, based on the quantum master equation and semi-group approach. The general expressions of several important performance parameters, such as the coefficient of performance, cooling rate and power input, are given. It is found that the coefficient of performance of this cycle is a close analogue of the classical Carnot-cycle. Some performance characteristic curves relating the cooling rate, the coefficient of performance and power input are plotted. Further, for high temperatures, the optimal relations between the cooling rate and the coefficient of performance are analyzed in detail

  7. A Brayton cycle solar dynamic heat receiver for space

    Science.gov (United States)

    Sedgwick, L. M.; Nordwall, H. L.; Kaufmann, K. J.; Johnson, S. D.

    1989-01-01

    The detailed design of a heat receiver developed to meet the requirements of the Space Station Freedom, which will be assembled and operated in low earth orbit beginning in the mid-1990's, is described. The heat receiver supplies thermal energy to a nominal 25-kW closed-Brayton-cycle power conversion unit. The receiver employs an integral thermal energy storage system utilizing the latent heat of a eutectic-salt phase-change mixture to store energy for eclipse operation. The salt is contained within a felt metal matrix which enhances heat transfer and controls the salt void distribution during solidification.

  8. Development and validation of models for simulation of supercritical carbon dioxide Brayton cycles and application to self-propelling heat removal systems in boiling water reactors

    OpenAIRE

    Venker, Jeanne

    2015-01-01

    The objective of the current work was to develop a model that is able to describe the transient behavior of supercritical carbon dioxide (sCO2) Brayton cycles, to be applied to self-propelling residual heat removal systems in boiling water reactors. The developed model has been implemented into the thermohydraulic system code ATHLET. By means of this improved ATHLET version, novel residual heat removal systems, which are based on closed sCO2 Brayton cycles, can be assessed as a retrofit measu...

  9. Advanced Supercritical Carbon Dioxide Brayton Cycle Development

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark [Univ. of Wisconsin, Madison, WI (United States); Sienicki, James [Argonne National Lab. (ANL), Argonne, IL (United States); Moisseytsev, Anton [Argonne National Lab. (ANL), Argonne, IL (United States); Nellis, Gregory [Univ. of Wisconsin, Madison, WI (United States); Klein, Sanford [Univ. of Wisconsin, Madison, WI (United States)

    2015-10-21

    Fluids operating in the supercritical state have promising characteristics for future high efficiency power cycles. In order to develop power cycles using supercritical fluids, it is necessary to understand the flow characteristics of fluids under both supercritical and two-phase conditions. In this study, a Computational Fluid Dynamic (CFD) methodology was developed for supercritical fluids flowing through complex geometries. A real fluid property module was implemented to provide properties for different supercritical fluids. However, in each simulation case, there is only one species of fluid. As a result, the fluid property module provides properties for either supercritical CO2 (S-CO2) or supercritical water (SCW). The Homogeneous Equilibrium Model (HEM) was employed to model the two-phase flow. HEM assumes two phases have same velocity, pressure, and temperature, making it only applicable for the dilute dispersed two-phase flow situation. Three example geometries, including orifices, labyrinth seals, and valves, were used to validate this methodology with experimental data. For the first geometry, S-CO2 and SCW flowing through orifices were simulated and compared with experimental data. The maximum difference between the mass flow rate predictions and experimental measurements is less than 5%. This is a significant improvement as previous works can only guarantee 10% error. In this research, several efforts were made to help this improvement. First, an accurate real fluid module was used to provide properties. Second, the upstream condition was determined by pressure and density, which determines supercritical states more precise than using pressure and temperature. For the second geometry, the flow through labyrinth seals was studied. After a successful validation, parametric studies were performed to study geometric effects on the leakage rate. Based on these parametric studies, an optimum design strategy for the see

  10. Multi-objective optimization of combined Brayton and inverse Brayton cycles using advanced optimization algorithms

    Science.gov (United States)

    Venkata Rao, R.; Patel, Vivek

    2012-08-01

    This study explores the use of teaching-learning-based optimization (TLBO) and artificial bee colony (ABC) algorithms for determining the optimum operating conditions of combined Brayton and inverse Brayton cycles. Maximization of thermal efficiency and specific work of the system are considered as the objective functions and are treated simultaneously for multi-objective optimization. Upper cycle pressure ratio and bottom cycle expansion pressure of the system are considered as design variables for the multi-objective optimization. An application example is presented to demonstrate the effectiveness and accuracy of the proposed algorithms. The results of optimization using the proposed algorithms are validated by comparing with those obtained by using the genetic algorithm (GA) and particle swarm optimization (PSO) on the same example. Improvement in the results is obtained by the proposed algorithms. The results of effect of variation of the algorithm parameters on the convergence and fitness values of the objective functions are reported.

  11. Comparison of various Brayton cycles for a Sodium-cooled Fast Reactor

    International Nuclear Information System (INIS)

    The nuclear energy is considered as one of the most realistic energy sources for both reducing the carbon dioxide emission and attaining sufficient and stable electricity supply for economy development. As a part of the nuclear energy development, many countries around the world are focusing on the next generation reactor development. One of the next generation reactors that is seriously being considered is the Sodium-cooled Fast Reactor (SFR). However, current SFR design faces the difficulty in public acceptance due to the potential threat from sodium-water reaction (SWR) when the current conventional steam Rankine cycle is utilized as a power conversion system for SFR. To substitute the violent sodium-water reaction with milder or no reaction, several Brayton cycle concepts including the S-CO2 cycle, helium cycle and nitrogen cycle are considered by many research organizations. This paper discusses these Brayton cycles'performance for SFR application compared to the current steam Rankine cycle

  12. NASA 30,000 hour test demonstration of closed Brayton cycle reliability

    Science.gov (United States)

    Mccormick, J. E.; Dunn, J. H.

    1977-01-01

    Four Brayton rotating units (BRU) developed by an American company were tested in connection with studies concerning the feasibility to use closed Brayton power conversion systems for space applications. The rotating assembly operates at a speed of 36,000 rpm and consists of a radial outflow compressor, a four-pole Rice alternator/motor, and a radial inflow turbine. The cycle working fluid consists of a mixture of helium and xenon. After 20,000 hours of operation, there was no apparent wear on failure mode to prevent attainment of the 5-year BRU design life objective.

  13. Preliminary Design of S-CO{sub 2} Brayton Cycle for KAIST Micro Modular Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Gu; Kim, Min Gil; Bae, Seong Jun; Lee, Jeong Ik [Korea Advanced Institue of Science and Technology, Daejeon (Korea, Republic of)

    2013-10-15

    This paper suggests a complete modular reactor with an innovative concept of reactor cooling by using a supercritical carbon dioxide directly. Authors propose the supercritical CO{sub 2} Brayton cycle (S-CO{sub 2} cycle) as a power conversion system to achieve small volume of power conversion unit (PCU) and to contain the core and PCU in one vessel for the full modularization. This study suggests a conceptual design of small modular reactor including PCU which is named as KAIST Micro Modular Reactor (MMR). As a part of ongoing research of conceptual design of KAIST MMR, preliminary design of power generation cycle was performed in this study. Since the targets of MMR are full modularization of a reactor system with S-CO{sub 2} coolant, authors selected a simple recuperated S-CO{sub 2} Brayton cycle as a power conversion system for KAIST MMR. The size of components of the S-CO{sub 2} cycle is much smaller than existing helium Brayton cycle and steam Rankine cycle, and whole power conversion system can be contained with core and safety system in one containment vessel. From the investigation of the power conversion cycle, recompressing recuperated cycle showed higher efficiency than the simple recuperated cycle. However the volume of heat exchanger for recompressing cycle is too large so more space will be occupied by heat exchanger in the recompressing cycle than the simple recuperated cycle. Thus, authors consider that the simple recuperated cycle is more suitable for MMR. More research for the KAIST MMR will be followed in the future and detailed information of reactor core and safety system will be developed down the road. More refined cycle layout and design of turbomachinery and heat exchanger will be performed in the future study.

  14. The role of real gas Brayton cycles for the use of liquid natural gas physical exergy

    International Nuclear Information System (INIS)

    When using the cooling capacity of LNG several thermodynamic schemes are proposable employing conventional and non conventional conversion cycles. All conventional systems make use of organic working fluids such as methane or propane in series of Rankine cycles used in a cascading mode. A simpler system is available, using a single cycle and a single fluid in a Brayton cycle. However ordinary Brayton cycles exhibit a modest efficiency. Resorting to Brayton cycles with strong real gas effects (which is possible selecting the base parameters of pressure and temperature in the vicinity of the critical point) improves considerable cycle performance. Since the level of cold in a LNG flow is thermodynamically predetermined, working fluids must be selected with a critical point which fit the LNG thermal capacity, i.e. some 5-15 C higher than the usual LNG temperature which is around -160 oC. Nitrogen was found as the best fluid to exploit real gas effects with efficiencies above 63% while perfect gas cycles give efficiencies around 56%. However, in real gas cycles the cooling capacity of LNG is only partially exploited: a better exploitation is obtained from perfect gas cycles or for more complex cascading Rankine cycle. Selecting working fluids with a higher critical temperature than nitrogen, as for example argon, the efficiency decreases to 58% respect to 63% for nitrogen, but the utilization of the cold of LNG improves from 0.30 MW/(kg/s) to 0.75 MW/(kg/s). Obviously as heat rejection temperature increases a larger fraction of cold in the LNG flow can be utilized. Combined cycles making use of a gas turbine offer also a good performance. The merits of real gas effect Brayton cycles also in this case remains evident. Finally, it is theoretically possible to use real gas effect Brayton cycles at low temperatures, which are typical of waste heat (say 100-150 oC: in this case cycle efficiency remain good, but power obtainable from a unit flow of LNG is modest. - Research

  15. Super-critical carbon dioxide based brayton cycle for Indian High Temperature Reactors

    International Nuclear Information System (INIS)

    The most effective way to improve economic competitiveness of NPPs is to enhance its efficiency which has remained static at around 33% since the first commercial LWR came into operation. New generation reactor designs including the six Gen-IV reactor concepts aim to increase the NPPs efficiency to almost 50%. This is proposed to be achieved by high temperature designs using Brayton cycle based power conversion systems. World over, Super-critical Carbon dioxide Brayton Cycle (SCBC) for power generation is an important R and D area. High efficiency SCBC power conversion system is proposed as power conversion system for Indian Molten Salt Breeder Reactor (IMSBR) and Innovative High Temperature Reactor (IHTR). This section provides the details regarding design and development of SCBC for these reactors. (author)

  16. Performance comparison of an irreversible closed variable-temperature heat reservoir Brayton cycle under maximum power density and maximum power conditions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.; Zheng, J.; Sun, F. [Naval University of Engineering, Wuhan (China); Wu, C. [US Naval Academy, Annapolis, MD (United States). Dept. of Mechanical Engineering

    2005-11-15

    The power density is taken as an objective for performance analysis of an irreversible closed Brayton cycle coupled to variable-temperature heat reservoirs. The analytical formulas about the relationship between power density and working fluid temperature ratio (pressure ratio) are derived with the heat resistance losses in the hot- and cold-side heat exchangers, the irreversible compression and expansion losses in the compressor and turbine, and the effect of the finite thermal capacity rate of the heat reservoirs. The obtained results are compared with those results obtained by using the maximum power criterion. The influences of some design parameters, including the temperature ratio of the heat reservoirs, the effectivenesses of the heat exchangers between the working fluid and the heat reservoirs, and the efficiencies of the compressor and the turbine, on the maximum power density are provided by numerical examples, and the advantages and disadvantages of maximum power density design are analysed. The power plant design with maximum power density leads to a higher efficiency and smaller size. When the heat transfers between the working fluid and the heat reservoirs are carried out ideally and the thermal capacity rates of the heat reservoirs are infinite, the results of this article become similar to those obtained in the recent literature. (author)

  17. A liquid-metal reactor/air Brayton-cycle option for a multimegawatt terrestrial power (MTP) plant

    International Nuclear Information System (INIS)

    The LMR/ABC concept presented provides a simple and safe approach to secure nuclear power generation to fulfill possible military requirements for 10-MWc terrestrial applications. The system utilizes an inherently safe liquid metal reactor and a simple, closed-cycle gas turbine power conversion system. The concept incorporates many passive safety features, and it exhibits operating characteristics that ensure the maximum protection against postulated nuclear accidents

  18. Performance improvement options for the supercritical carbon dioxide brayton cycle

    International Nuclear Information System (INIS)

    The supercritical carbon dioxide (S-CO2) Brayton cycle is under development at Argonne National Laboratory as an advanced power conversion technology for Sodium-Cooled Fast Reactors (SFRs) as well as other Generation IV advanced reactors as an alternative to the traditional Rankine steam cycle. For SFRs, the S-CO2 Brayton cycle eliminates the need to consider sodium-water reactions in the licensing and safety evaluation, reduces the capital cost of the SFR plant, and increases the SFR plant efficiency. Even though the S-CO2 cycle has been under development for some time and optimal sets of operating parameters have been determined, those earlier development and optimization studies have largely been directed at applications to other systems such as gas-cooled reactors which have higher operating temperatures than SFRs. In addition, little analysis has been carried out to investigate cycle configurations deviating from the selected 'recompression' S-CO2 cycle configuration. In this work, several possible ways to improve S-CO2 cycle performance for SFR applications have been identified and analyzed. One set of options incorporates optimization approaches investigated previously, such as variations in the maximum and minimum cycle pressure and minimum cycle temperature, as well as a tradeoff between the component sizes and the cycle performance. In addition, the present investigation also covers options which have received little or no attention in the previous studies. Specific options include a 'multiple-recompression' cycle configuration, intercooling and reheating, as well as liquid-phase CO2 compression (pumping) either by CO2 condensation or by a direct transition from the supercritical to the liquid phase. Some of the options considered did not improve the cycle efficiency as could be anticipated beforehand. Those options include: a double recompression cycle, intercooling between the compressor stages, and reheating between the turbine stages. Analyses carried

  19. Thermodynamic Modeling for Open Combined Regenerative Brayton and Inverse Brayton Cycles with Regeneration before the Inverse Cycle

    Directory of Open Access Journals (Sweden)

    Lingen Chen

    2012-01-01

    Full Text Available A thermodynamic model of an open combined regenerative Brayton and inverse Brayton cycles with regeneration before the inverse cycle is established in this paper by using thermodynamic optimization theory. The flow processes of the working fluid with the pressure drops and the size constraint of the real power plant are modeled. There are 13 flow resistances encountered by the working fluid stream for the cycle model. Four of these, the friction through the blades and vanes of the compressors and the turbines, are related to the isentropic efficiencies. The remaining nine flow resistances are always present because of the changes in flow cross-section at the compressor inlet of the top cycle, regenerator inlet and outlet, combustion chamber inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger inlet, and compressor inlet of the bottom cycle. These resistances associated with the flow through various cross-sectional areas are derived as functions of the compressor inlet relative pressure drop of the top cycle, and control the air flow rate, the net power output and the thermal efficiency. The analytical formulae about the power output, efficiency and other coefficients are derived with 13 pressure drop losses. It is found that the combined cycle with regenerator can reach higher thermal efficiency but smaller power output than those of the base combined cycle at small compressor inlet relative pressure drop of the top cycle.

  20. Operation and analysis of a supercritical CO2 Brayton cycle.

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Steven Alan; Radel, Ross F.; Vernon, Milton E.; Pickard, Paul S.; Rochau, Gary Eugene

    2010-09-01

    Sandia National Laboratories is investigating advanced Brayton cycles using supercritical working fluids for use with solar, nuclear or fossil heat sources. The focus of this work has been on the supercritical CO{sub 2} cycle (S-CO2) which has the potential for high efficiency in the temperature range of interest for these heat sources, and is also very compact, with the potential for lower capital costs. The first step in the development of these advanced cycles was the construction of a small scale Brayton cycle loop, funded by the Laboratory Directed Research & Development program, to study the key issue of compression near the critical point of CO{sub 2}. This document outlines the design of the small scale loop, describes the major components, presents models of system performance, including losses, leakage, windage, compressor performance, and flow map predictions, and finally describes the experimental results that have been generated.

  1. Proposal for an advanced heat source assembly for the Isotope Brayton Power System. Volume 1. Technical program and statement of work

    Energy Technology Data Exchange (ETDEWEB)

    1974-12-09

    The technical program plan for evaluating the performance and safety of a radioisotope-fueled Brayton power system for space vehicles is presented with schedules for evaluating heat source design and safety, for specifying power system requirements, and for the development and operation of a ground demonstration system. (LCL)

  2. Calculation principles of humid air in a reversed Brayton cycle

    Energy Technology Data Exchange (ETDEWEB)

    Backman, J. [Lappeenranta Univ. of Technology (Finland). Dept. of Energy Technology

    1997-12-31

    The article presents a calculation method for reversed Brayton cycle that uses humid air as working medium. The reversed Brayton cycle can be employed as an air dryer, a heat pump or a refrigerating machine. In this research the use of humid air as a working fluid has an environmental advantage, as well. In this method especially the expansion process in the turbine is important because of the condensation of the water vapour in the humid air. This physical phenomena can have significant effects on the level of performance of the application. The expansion process differs physically from the compression process, when the water vapour in the humid air begins to condensate. In the thermodynamic equilibrium of the flow, the water vapour pressure in humid air cannot exceed the pressure of saturated water vapour in corresponding temperature. Expansion calculation during operation around the saturation zone is based on a quasistatic expansion, in which the system after the turbine is in thermodynamical equilibrium. The state parameters are at every moment defined by the equation of state, and there is no supercooling in the vapour. Following simplifications are used in the calculations: The system is assumed to be adiabatic. This means that there is no heat transfer to the surroundings. This is a common practice, when the temperature differences are moderate as here; The power of the cooling is omitted. The cooling construction is very dependent on the machine and the distribution of the losses; The flow is assumed to be one-dimensional, steady-state and homogenous. The water vapour condensing in the turbine can cause errors, but the errors are mainly included in the efficiency calculation. (author) 11 refs.

  3. Parametric Investigation and Thermoeconomic Optimization of a Combined Cycle for Recovering the Waste Heat from Nuclear Closed Brayton Cycle

    Directory of Open Access Journals (Sweden)

    Lihuang Luo

    2016-01-01

    Full Text Available A combined cycle that combines AWM cycle with a nuclear closed Brayton cycle is proposed to recover the waste heat rejected from the precooler of a nuclear closed Brayton cycle in this paper. The detailed thermodynamic and economic analyses are carried out for the combined cycle. The effects of several important parameters, such as the absorber pressure, the turbine inlet pressure, the turbine inlet temperature, the ammonia mass fraction, and the ambient temperature, are investigated. The combined cycle performance is also optimized based on a multiobjective function. Compared with the closed Brayton cycle, the optimized power output and overall efficiency of the combined cycle are higher by 2.41% and 2.43%, respectively. The optimized LEC of the combined cycle is 0.73% lower than that of the closed Brayton cycle.

  4. Design Development Analyses in Support of a Heatpipe-Brayton Cycle Heat Exchanger

    Science.gov (United States)

    Steeve, Brian E.; Kapernick, Richard J.

    2004-01-01

    One of the power systems under consideration for nuclear electric propulsion or as a planetary surface power source is a heatpipe-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the heatpipes to the Brayton gas via a heat exchanger attached to the heatpipes. This paper discusses the fluid, thermal and structural analyses that were performed in support of the design of the heat exchanger to be tested in the SAFE-100 experimental program at the Marshall Space Flight Center: An important consideration throughout the design development of the heat exchanger w its capability to be utilized for higher power and temperature applications. This paper also discusses this aspect of the design and presents designs for specific applications that are under consideration.

  5. Overview of CNES-CEA joint program on space nuclear Brayton systems

    International Nuclear Information System (INIS)

    In this paper French studies on 20-kWe space nuclear power systems are presented. The gas-cooled reactor nuclear systems, some investigations on advanced thermal neutron spectrum systems, a support work on materials, parameters optimization and operating transient analysis, and Brayton cycle-thermoelectric and nuclear-non nuclear systems comparisons

  6. Modeling and Simulation of a Desiccant Assisted Brayton Refrigeration Cycle

    OpenAIRE

    Nobrega, Carlos E.L.; Sphaier, Leandro Alcoforado

    2012-01-01

    The phase-out of CFCs has shed a new light over natural refrigerants, which have null global warming potentials. Air would be a natural choice, and although the Brayton cycle usually exhibits a lower coefficient of performance when compared to vapor-compression systems of same capacity, it has been considered in applications other than aircraft cooling. These include gas separation, food processing and preservation, refrigerated containers and train air-conditioning. Price perspectives in the...

  7. Exergy analyses of an endoreversible closed regenerative Brayton cycle CCHP plant

    OpenAIRE

    Bo Yang, Lingen Chen, Fengrui Sun

    2014-01-01

    An endoreversible closed regenerative Brayton cycle CCHP (combined cooling, heating and power) plant coupled to constant-temperature heat reservoirs is presented using finite time thermodynamics (FTT). The CCHP plant includes an endoreversible closed regenerative Brayton cycle, an endoreversible four-heat-reservoir absorption refrigerator and a heat recovery device of thermal consumer. The heat-resistance losses in the hot-, cold-, thermal consumer-, generator-, condenser-, evaporator- and ab...

  8. Systems Analyses of Advanced Brayton Cycles For High Efficiency Zero Emission Plants

    Energy Technology Data Exchange (ETDEWEB)

    A. D. Rao; J. Francuz; H. Liao; A. Verma; G. S. Samuelsen

    2006-11-01

    Table 1 shows that the systems efficiency, coal (HHV) to power, is 35%. Table 2 summarizes the auxiliary power consumption within the plant. Thermoflex was used to simulate the power block and Aspen Plus the balance of plant. The overall block flow diagram is presented in Figure A1.3-1 and the key unit process flow diagrams are shown in subsequent figures. Stream data are given in Table A1.3-1. Equipment function specifications are provided in Tables A1.3-2 through 17. The overall plant scheme consists of a cryogenic air separation unit supplying 95% purity O{sub 2} to GE type high pressure (HP) total quench gasifiers. The raw gas after scrubbing is treated in a sour shift unit to react the CO with H{sub 2}O to form H{sub 2} and CO{sub 2}. The gas is further treated to remove Hg in a sulfided activated carbon bed. The syngas is desulfurized and decarbonized in a Selexol acid gas removal unit and the decarbonized syngas after humidification and preheat is fired in GE 7H type steam cooled gas turbines. Intermediate pressure (IP) N{sub 2} from the ASU is also supplied to the combustors of the gas turbines as additional diluent for NOx control. A portion of the air required by the ASU is extracted from the gas turbines. The plant consists of the following major process units: (1) Air Separation Unit (ASU); (2) Gasification Unit; (3) CO Shift/Low Temperature Gas Cooling (LTGC) Unit; (4) Acid Gas Removal Unit (AGR) Unit; (5) Fuel Gas Humidification Unit; (6) Carbon Dioxide Compression/Dehydration Unit; (7) Claus Sulfur Recovery/Tail Gas Treating Unit (SRU/TGTU); and (8) Power Block.

  9. Preliminary design of a Brayton cycle as a standalone Decay Heat Removal system for the Gas-cooled Fast Reactor

    International Nuclear Information System (INIS)

    This paper reports a preliminary design study of a Brayton cycle which would be a dedicated, standalone Decay Heat Removal (DHR) loop of the Gas-cooled Fast Reactor (GFR). In comparison to the DHR reference strategy developed during the GFR pre-conceptual design phase (which was completed by the CEA at the end of 2007), the salient feature of this alternative device would be to combine the energetic autonomy of the natural convection process - which is foreseen for operation at high and medium pressures - to the efficiency of the forced convection process which is foreseen for operation down to very low pressures. An analytical model, the so-called 'Brayton scoping' model, is described in the paper. This is based on simplified thermodynamical and aerodynamical equations and was developed to highlight design choices. First simulations of the proposed device's performance during loss-of-coolant-accident (LOCA) transients have been performed using the CATHARE code, and these are also reported. Analysis of the simulation results are consistent with the first insights obtained from usage of the 'Brayton scoping' model, e.g. the turbomachine accelerates during the depressurization process to tend towards a steady rotational speed value which is inversely proportional to the pressure. For small break LOCA events, the device operates successfully as regards its safety function and delivers to the core a relatively unperturbed cooling mass flowrate as a function of pressure change. However, further studies are required for medium to large break sizes, since certain stability concerns have been met in such cases. For example, an unexpected turbomachine stoppage was induced during the transients, resulting in loss of the necessary core cooling mass flow. (author)

  10. Automatic Control Strategy Development for the Supercritical CO2 Brayton Cycle for LFR Autonomous Load Following

    International Nuclear Information System (INIS)

    The supercritical carbon dioxide (S-CO2) Brayton cycle is a promising advanced alternative to the Rankine saturated steam cycle and ideal gas Brayton cycle for the energy converters of specific reactor concepts belonging to the U.S. Department of Energy Generation IV Nuclear Energy Systems Initiative. A new plant dynamics analysis computer code has been developed for simulation of the S-CO2 Brayton cycle coupled to an autonomous Lead-Cooled Fast Reactor (LFR). The plant dynamics code was used to develop an automatic control strategy for the whole plant in response to changes in the demand from the electrical grid. The specific features of the S-CO2 Brayton cycle that result in limitations on the control range and speed of specific control mechanisms are discussed. Calculations of whole-plant responses to plant operational transients involving step and continuous changes in grid demand are demonstrated. (authors)

  11. Use of Multiple Reheat Helium Brayton Cycles to Eliminate the Intermediate Heat Transfer Loop for Advanced Loop Type SFRs

    Energy Technology Data Exchange (ETDEWEB)

    Haihua Zhao; Hongbin Zhang; Samuel E. Bays

    2009-05-01

    The sodium intermediate heat transfer loop is used in existing sodium cooled fast reactor (SFR) plant design as a necessary safety measure to separate the radioactive primary loop sodium from the water of the steam Rankine power cycle. However, the intermediate heat transfer loop significantly increases the SFR plant cost and decreases the plant reliability due to the relatively high possibility of sodium leakage. A previous study shows that helium Brayton cycles with multiple reheat and intercooling for SFRs with reactor outlet temperature in the range of 510°C to 650°C can achieve thermal efficiencies comparable to or higher than steam cycles or recently proposed supercritical CO2 cycles. Use of inert helium as the power conversion working fluid provides major advantages over steam or CO2 by removing the requirement for safety systems to prevent and mitigate the sodium-water or sodium-CO2 reactions. A helium Brayton cycle power conversion system therefore makes the elimination of the intermediate heat transfer loop possible. This paper presents a pre-conceptual design of multiple reheat helium Brayton cycle for an advanced loop type SFR. This design widely refers the new horizontal shaft distributed PBMR helium power conversion design features. For a loop type SFR with reactor outlet temperature 550°C, the design achieves 42.4% thermal efficiency with favorable power density comparing with high temperature gas cooled reactors.

  12. Rankline-Brayton engine powered solar thermal aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Charles L. (Livermore, CA)

    2012-03-13

    A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  13. Rankine-Brayton engine powered solar thermal aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Charles L. (Livermore, CA)

    2009-12-29

    A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  14. Back work ratio of Brayton cycle; La relacion de trabajo de retroceso de un ciclo Brayton

    Energy Technology Data Exchange (ETDEWEB)

    Malaver de la Fuente, M. [Universidad Maritima del Caribe (Venezuela)]. E-mail: mmf_umc@hotmail.com

    2010-07-15

    This paper analyzes the existing relation between temperatures, back work ratio and net work of Brayton cycle, a cycle that describes gas turbine engines performance. The application of computational software helps to show the influence of back work ratio or coupling ratio, compressor and turbine inlet temperatures in an ideal thermodynamical cycle. The results lead to deduce that the maximum value reached in back work ratio will depend on the ranges of maximum and minimal temperatures of Brayton cycle. [Spanish] En este articulo se estudia la relacion que existe entre las temperaturas, la relacion de trabajo de retroceso y el trabajo neto en el ciclo Brayton, que es el ciclo ideal que describe el comportamiento de los motores de turbina de gas. La aplicacion de programas computarizados ayuda a mostrar la influencia de la relacion de trabajo de retroceso o relacion de acoplamiento, la temperatura de entrada al compresor y la temperatura de entrada a la turbina en este ciclo termodinamico ideal. Los resultados obtenidos permiten deducir que el valor maximo que alcanza la relacion de trabajo de retroceso dependera de los limites de temperatura maxima y minima impuestos en el ciclo Brayton.

  15. Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle

    Science.gov (United States)

    Wang, Hao; Wu, GuoXing

    2012-02-01

    A model of the irreversible regenerative Brayton refrigeration cycle working with paramagnetic materials is established, in which the regeneration problem in two constant-magnetic field processes and the irreversibility in two adiabatic processes are considered synthetically. Expressions for the COP, cooling rate, power input, the minimum ratio of the two magnetic fields, etc., are derived. It is found that the influence of the irreversibility and the regeneration on the main performance parameters of the magnetic Brayton refrigerator is remarkable. It is important that we have obtained several optimal criteria, which may provide some theoretical basis for the optimal design and operation of the Brayton refrigerator. The results obtained in the paper can provide some new theoretical information for the optimal design and performance improvement of real Brayton refrigerators.

  16. Test plan: Brayton Isotope Power System Ground Demonstration System (BIPS-GDS)

    Energy Technology Data Exchange (ETDEWEB)

    1976-06-13

    The purpose of this test plan is to provide an overall outline of all testing to be accomplished on the GDS. Included in this test plan are administrative requirements, instrumentation accuracies, instrumentation, equipment definitions, system test setup, and facility installation. The test program will enable collection of sufficient data to establish material, component, and system design integrity. The data will also be used to establish and evaluate component and system performance and reliability characteristics, verification of proper system component integration prior to initiation of Phase II, and flight system (FS) development.

  17. Test plan: Brayton Isotope Power System Ground Demonstration System (BIPS-GDS)

    International Nuclear Information System (INIS)

    The purpose of this test plan is to provide an overall outline of all testing to be accomplished on the GDS. Included in this test plan are administrative requirements, instrumentation accuracies, instrumentation, equipment definitions, system test setup, and facility installation. The test program will enable collection of sufficient data to establish material, component, and system design integrity. The data will also be used to establish and evaluate component and system performance and reliability characteristics, verification of proper system component integration prior to initiation of Phase II, and flight system (FS) development

  18. Exergy analyses of an endoreversible closed regenerative Brayton cycle CCHP plant

    Directory of Open Access Journals (Sweden)

    Bo Yang, Lingen Chen, Yanlin Ge, Fengrui Sun

    2014-01-01

    Full Text Available An endoreversible closed regenerative Brayton cycle CCHP (combined cooling, heating and power plant coupled to constant-temperature heat reservoirs is presented using finite time thermodynamics (FTT. The CCHP plant includes an endoreversible closed regenerative Brayton cycle, an endoreversible four-heat-reservoir absorption refrigerator and a heat recovery device of thermal consumer. The heat-resistance losses in the hot-, cold-, thermal consumer-, generator-, condenser-, evaporator- and absorber-side heat exchangers and regenerator are considered. The performance of the CCHP plant is studied from the exergetic perspective, and the analytical formulae about exergy output rate and exergy efficiency are derived. Through numerical calculations, the pressure ratio of regenerative Brayton cycle is optimized, the effects of heat conductance of regenerator and ratio of heat demanded by the thermal consumer to power output on dimensionless exergy output rate and exergy efficiency are analyzed.

  19. Volatile organic compound recovery by Brayton cycle Heat Pump

    International Nuclear Information System (INIS)

    Organic solvent emissions from industrial processes are a major source of volatile organic compounds (VOCs). VOCs contribute to the formation of photochemical ozone, a major component of smog. Over 90 percent of the organic solvents used in industry are emitted. Not only does this represent a significant source of air pollution, but it also represents a waste of energy resources. A pound of solvent requires an average of 23,000 Btu of energy to produce, in the form of the feedstock and processing energy expenditures. In 1988, the total amount of solvents emitted in the United States was over 4 billion pounds and represent 100 trillion Btu in energy loss. In the mid-1970's, the 3M Company began developing the Brayton Cycle Heat Pump for solvent recovery (BCSRHP). In 1979, the US Department of Energy (DOE) began a project to fabricate and install a BCSRHP in a 3M plant in Hutchinson, Minnesota. DOE has continued sponsoring the development of a large BCSRHP system with 3M, and NUCON International (NUCON). In 1989 DOE and NUCON, with cosponsorship from the Electric Power Research Institute and Southern California Edison Company began development of a small-scale system for use by small emitters. To obtain data for design of the small-scale system, a small, mobile pilot plant was built by NUCON. Between 1990 and 1991, the pilot plant was demonstrated at four industrial sites in Southern California. The operation of the pilot plant was continuously monitored during the demonstrations, and its ability to remove VOCS, utility consumption and other operating characteristics were recorded and its performance quantified

  20. Scaling considerations for a multi-megawatt class supercritical CO2 brayton cycle and commercialization.

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Darryn D.; Holschuh, Thomas Vernon,; Conboy, Thomas M.; Pasch, James Jay; Wright, Steven Alan; Rochau, Gary Eugene; Fuller, Robert Lynn [Barber-Nichols, Inc., Arvada, CO

    2013-11-01

    Small-scale supercritical CO2 demonstration loops are successful at identifying the important technical issues that one must face in order to scale up to larger power levels. The Sandia National Laboratories supercritical CO2 Brayton cycle test loops are identifying technical needs to scale the technology to commercial power levels such as 10 MWe. The small size of the Sandia 1 MWth loop has demonstration of the split flow loop efficiency and effectiveness of the Printed Circuit Heat Exchangers (PCHXs) leading to the design of a fully recuperated, split flow, supercritical CO2 Brayton cycle demonstration system. However, there were many problems that were encountered, such as high rotational speeds in the units. Additionally, the turbomachinery in the test loops need to identify issues concerning the bearings, seals, thermal boundaries, and motor controller problems in order to be proved a reliable power source in the 300 kWe range. Although these issues were anticipated in smaller demonstration units, commercially scaled hardware would eliminate these problems caused by high rotational speeds at small scale. The economic viability and development of the future scalable 10 MWe solely depends on the interest of DOE and private industry. The Intellectual Property collected by Sandia proves that the ~10 MWe supercritical CO2 power conversion loop to be very beneficial when coupled to a 20 MWth heat source (either solar, geothermal, fossil, or nuclear). This paper will identify a commercialization plan, as well as, a roadmap from the simple 1 MWth supercritical CO2 development loop to a power producing 10 MWe supercritical CO2 Brayton loop.

  1. Phase 2 Brayton/Rankine 10-ton gas-fired space-conditioning system

    Science.gov (United States)

    1982-07-01

    The technical accomplishments to date in the design, development, and demonstration program leading to commercialization of a 10 ton heat actuated space conditioning system for light commercialization of a 10 ton heat actuated space conditioning system for light commercial building applications are summarized. The system consists of a natural gas powered Brayton cycle engine and a Rankine cycle heat pump, combined in a single roof top package. The heat actuated space conditioning system provides more efficient use of natural gas and is intended as an all gas alternative to the electric heat pump. The system employs a subatmospheric natural gas fired heat pump. A centrifugal R-12 refrigerant compressor is driven directly from the Brayton engine rotating group through a hermetically sealed coupling. Unique features that offer high life cycle performance include a permanent magnet coupling, foil bearings, an atmospheric in-line combustor, and a high temperature recuperator.

  2. Hopf limit cycles estimation in power systems

    Energy Technology Data Exchange (ETDEWEB)

    Barquin, J.; Gomez, T.; Pagola, L.F. [Univ. Pontificia Comillas, Madrid (Spain). Inst. de Investigacion Tecnologica

    1995-11-01

    This paper addresses the computation of the Hopf limit cycle. This limit cycle is associated to the appearance of an oscillatory instability in dynamical power systems. An algorithm is proposed to estimate the dimensions and shape of this limit cycle. The algorithm is computationally efficient and is able to deal with large power systems. 7 refs, 4 figs, 1 tab

  3. Investigation on the performance of the supercritical Brayton cycle with CO2-based binary mixture as working fluid for an energy transportation system of a nuclear reactor

    International Nuclear Information System (INIS)

    In this study, the performance of a SBC (supercritical gas Brayton cycle) using CO2-based binary mixtures as the working fluids have been studied. Based on the thermodynamic analyses, an in-house code has been developed to determine the cycle efficiency and the amounts of heat transfer in the HTR (high temperature recuperator) and the LTR (low temperature recuperator) with different CO2/additive gas ratios. Several gases are selected as potential additives, including O2, He, Ar, Kr, butane and cyclohexane. Compared with the Brayton cycle with pure S–CO2 (supercritical carbon dioxide) as the working fluid, it is found that both CO2–He and CO2–Kr mixtures can improve the thermodynamic performances of the SBC by increasing the cycle efficiency and decreasing the amounts of heat transfer in the HTR and LTR. For the cycles with the pure S–CO2 mixture, CO2–butane mixture and CO2–cyclohexane mixture as the working fluids, the cycle efficiencies decrease with increasing main compressor inlet temperature. However, when the main compressor inlet temperature is above the critical temperature of pure CO2, the cycle efficiencies of the cycles with CO2–butane mixture and CO2–cyclohexane mixture are higher than that of the cycle with pure CO2 as the working fluid. For the cycles with CO2-based binary mixtures and pure S–CO2 as the working fluids, the higher reactor outlet temperature always results into higher cycle efficiencies and larger amount of heat transfer in the HTR and smaller amount of heat transfer in the LTR. - Highlights: • The Brayton cycle performance with different mixtures as working fluids is studied. • Thermodynamic analysis is carried out to evaluate cycle efficiency and heat transfer in HTR and LTR. • The optimum working parameters of the Brayton cycle is proposed to improve working performance

  4. Heat exchanger optimization of a closed Brayton cycle for nuclear space propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Guilherme B.; Guimaraes, Lamartine N.F.; Braz Filho, Francisco A., E-mail: gbribeiro@ieav.cta.br, E-mail: guimarae@ieav.cta.br, E-mail: braz@ieav.cta.br [Instituto de Estudos Avancados (IEAV), Sao Jose dos Campos, SP (Brazil). Divisao de Energia Nuclear

    2015-07-01

    Nuclear power systems turned to space electric propulsion differs strongly from usual ground-based power systems regarding the importance of overall size and weight. For propulsion power systems, weight and efficiency are essential drivers that should be managed during conception phase. Considering that, this paper aims the development of a thermal model of a closed Brayton cycle that applies the thermal conductance of heat exchangers in order to predict the energy conversion performance. The centrifugal-flow turbine and compressor characterization were achieved using algebraic equations from literature data. The binary mixture of He-Xe with molecular weight of 40 g/mole is applied and the impact of heat exchanger optimization in thermodynamic irreversibilities is evaluated in this paper. (author)

  5. Heat exchanger optimization of a closed Brayton cycle for nuclear space propulsion

    International Nuclear Information System (INIS)

    Nuclear power systems turned to space electric propulsion differs strongly from usual ground-based power systems regarding the importance of overall size and weight. For propulsion power systems, weight and efficiency are essential drivers that should be managed during conception phase. Considering that, this paper aims the development of a thermal model of a closed Brayton cycle that applies the thermal conductance of heat exchangers in order to predict the energy conversion performance. The centrifugal-flow turbine and compressor characterization were achieved using algebraic equations from literature data. The binary mixture of He-Xe with molecular weight of 40 g/mole is applied and the impact of heat exchanger optimization in thermodynamic irreversibilities is evaluated in this paper. (author)

  6. Application of exergetic sustainability index to a nano-scale irreversible Brayton cycle operating with ideal Bose and Fermi gasses

    International Nuclear Information System (INIS)

    Highlights: • An irreversible Brayton cycle operating quantum gasses is considered. • Exergetic sustainability index is derived for nano-scale cycles. • Nano-scale effects are considered. • Calculation are conducted for irreversible cycles. • Numerical results are presented and discussed. - Abstract: In this study, a nano-scale irreversible Brayton cycle operating with quantum gasses including Bose and Fermi gasses is researched. Developments in the nano-technology cause searching the nano-scale machines including thermal systems to be unavoidable. Thermodynamic analysis of a nano-scale irreversible Brayton cycle operating with Bose and Fermi gasses was performed (especially using exergetic sustainability index). In addition, thermodynamic analysis involving classical evaluation parameters such as work output, exergy output, entropy generation, energy and exergy efficiencies were conducted. Results are submitted numerically and finally some useful recommendations were conducted. Some important results are: entropy generation and exergetic sustainability index are affected mostly for Bose gas and power output and exergy output are affected mostly for the Fermi gas by x. At the high temperature conditions, work output and entropy generation have high values comparing with other degeneracy conditions

  7. Application of exergetic sustainability index to a nano-scale irreversible Brayton cycle operating with ideal Bose and Fermi gasses

    Energy Technology Data Exchange (ETDEWEB)

    Açıkkalp, Emin, E-mail: eacikkalp@gmail.com [Department of Mechanical and Manufacturing Engineering, Engineering Faculty, Bilecik S.E. University, Bilecik (Turkey); Caner, Necmettin [Department of Chemistry, Faculty of Arts and Sciences, Eskisehir Osmangazi University, Eskisehir (Turkey)

    2015-09-25

    Highlights: • An irreversible Brayton cycle operating quantum gasses is considered. • Exergetic sustainability index is derived for nano-scale cycles. • Nano-scale effects are considered. • Calculation are conducted for irreversible cycles. • Numerical results are presented and discussed. - Abstract: In this study, a nano-scale irreversible Brayton cycle operating with quantum gasses including Bose and Fermi gasses is researched. Developments in the nano-technology cause searching the nano-scale machines including thermal systems to be unavoidable. Thermodynamic analysis of a nano-scale irreversible Brayton cycle operating with Bose and Fermi gasses was performed (especially using exergetic sustainability index). In addition, thermodynamic analysis involving classical evaluation parameters such as work output, exergy output, entropy generation, energy and exergy efficiencies were conducted. Results are submitted numerically and finally some useful recommendations were conducted. Some important results are: entropy generation and exergetic sustainability index are affected mostly for Bose gas and power output and exergy output are affected mostly for the Fermi gas by x. At the high temperature conditions, work output and entropy generation have high values comparing with other degeneracy conditions.

  8. Techno-economic studies of environmentally friendly Brayton cycles in the petrochemical industry

    OpenAIRE

    Nkoi, Barinyima

    2014-01-01

    Brayton cycles are open gas turbine cycles extensively used in aviation and industrial applications because of their advantageous volume and weight characteristics. With the bulk of waste exhaust heat and engine emissions associated, there is need to be mindful of environmentally-friendliness of these engine cycles, not compromising good technical performance, and economic viability. This research considers assessment of power plants in helicopters, and aeroderivative ind...

  9. Conceptual Design of S-CO2 Brayton Cycle Radial Turbomachinery for KAIST Micro Modular Reactor

    International Nuclear Information System (INIS)

    KAIST proposed a new SMR design, which utilizes S-CO2 as the working fluid. It was named as KAIST MMR. Compared with existing SMR concepts, KAIST MMR has advantages of achieving smaller volume of power conversion unit (PCU) and containing the core and PCU in one vessel for the complete modularization. Authors noticed that the compressor and turbine assumed performances of KAIST MMR were conservatively selected previously. Thus, this paper tries to address the best estimate values of each turbomachinery in 10MWe class KAIST MMR. The turbomachinery size of the S-CO2 cycle is smaller than helium Brayton cycle and steam Rankine cycle. The suggested SMR concept adopts passive cooling system by using air. This method can cool reactor without external electricity supply. Small size and more flexible installation in the inland area will be necessary characteristics for the future nuclear application in the water limited region. KAIST MMR meets all these requirements by utilizing S-CO2 as a working fluid. This paper presents the work for further increasing the system performance by estimating the component efficiency more realistically. The cycle layout adopted for the application is S-CO2 recuperated Brayton cycle. The best efficiency of compressor and turbine was evaluated to be 84.94% and 90.94%, respectively. By using KAIST in-house code, thermal efficiency and net output were increased to 35.81% and 12.45MWe, respectively, for the same core thermal power. More refined cycle layout and suitable turbomachinery design will be performed in the near future

  10. A treatment of thermal efficiency improvement in the Brayton cycle

    International Nuclear Information System (INIS)

    So far, as the working fluid for power-generating plants, mainly water and air (combustion gas) have been used. In this study, in regeneration and isothermal compression processes being considered as the means for the efficiency improvement in Brayton cycle, the investigation of equivalent graphical presentation method with T-S diagrams, the introduction of the new characteristic number expressing the possibility of thermal efficiency improvement by regeneration, and the investigation of the effect of the difference of working fluid on thermal efficiency were carried out. Next, as the cycle approximately realizing isothermal compression process with condensation process, the super-critical pressure cycle with liquid phase compression was rated, and four working fluids, NH3, SO2, CO2 and H2O were examined as perfect gas and real gas. The advantage of CO2 regeneration for the thermal efficiency improvement was clarified by using the dimensionless characteristic number. The graphical presentation of effective work, the thermal efficiency improvement by regeneration, the thermal efficiency improvement by making compression process isothermal, the effect on thermal efficiency due to various factors and working fluids, the characteristic number by regeneration, and the application to real working fluids are reported. (Kako, I.)

  11. Design of a three-phase, 15-kilovolt-ampere static inverter for motor-starting a Brayton space power system

    Science.gov (United States)

    Frye, R. J.; Birchenough, A. G.

    1971-01-01

    The design of a three-phase, 400-Hz, 15-kVA static inverter for motor-starting the 2- to 15-kWe Brayton electrical space power system is described. The inverter operates from a nominal 56-V dc source to provide a 28-V, rms, quasi-square-wave output. The inverter is capable of supplying a 200-A peak current. Integrated circuitry is used to generate the three-phase, 400-Hz reference signals. Performance data for a drive stage that improves switching speed and provides efficient operation over a range of output current and drive supply voltage are presented. A transformerless, transistor output stage is used.

  12. Analysis of transient coolant void formation during a guillotine-type HX tube rupture event in the Star-LM system employing a supercritical CO2 Brayton cycle

    International Nuclear Information System (INIS)

    One proposed concept for the STAR-LM Lead Fast Reactor (LFR) incorporates a supercritical CO2 gas turbine Brayton cycle to achieve high cycle efficiency and reduced plant footprint. In this design, 100+% of core full power is transferred by natural circulation from the core, located at the bottom of the reactor vessel, to in-vessel heat exchangers (HXs) located at the top of the vessel in the annulus between the core shroud and vessel inner wall. Although this approach extremely simplifies the plant design, the presence of the HXs within the vessel raises concerns regarding the potential rupture of a HX tube that would initiate a high-pressure blowdown of CO2 into the lead coolant. The principal issue is to what extent, if any, is void entrained downwards with the coolant and then upwards through the core where adverse reactivity effects or degraded heat removal could result. To address this question, a scoping analysis of transient void formation during a guillotine-type HX tube rupture event in the STAR-LM employing a supercritical CO2 Brayton cycle has been performed. The void formation process is evaluated by solving a coupled set of ordinary differential equations describing: i) the supercritical CO2 blowdown, ii) bubble center-of-mass trajectory, iii) bubble growth rate, iv) bubble gas internal energy, and v) discrete bubble formation rate due to Taylor instability at the bubble/coolant interface. The results indicate that for thermal hydraulic conditions consistent with the current STAR-LM design, the peak blowdown rate from a single tube rupture is ∼ 2.5 kg/sec. The void formation process is dominated by large coherent gas bubbles that penetrate minimally downwards into the coolant due to the large coolant density. Rather, the gas pockets are predicted to periodically rise due to buoyancy and vent to the core cover gas region, as opposed to being swept downwards with the coolant. Moreover, the total CO2 fraction that is rendered in the form of discrete

  13. Creep Property Characterization of Potential Brayton Cycle Impeller and Duct Materials

    Science.gov (United States)

    Gabb, Timothy P.; Gayda, John; Garg, Anita

    2007-01-01

    Cast superalloys have potential applications in space as impellers within closed-loop Brayton cycle nuclear power generation systems. Likewise wrought superalloys are good candidates for ducts and heat exchangers transporting the inert working gas in a Brayton-based power plant. Two cast superalloys, Mar-M247LC and IN792, and a NASA GRC powder metallurgy superalloy, LSHR, have been screened to compare their respective capabilities for impeller applications. Mar-M247LC has been selected for additional long term evaluations. Initial tests in helium indicate this inert environment may debit long term creep resistance of this alloy. Several wrought superalloys including Hastelloy® X, Inconel® 617, Inconel® 740, Nimonic® 263, Incoloy® MA956, and Haynes 230 are also being screened to compare their capabilities for duct applications. Haynes 230 has been selected for additional long term evaluations. Initial tests in helium are just underway for this alloy. These proposed applications would require sufficient strength and creep resistance for long term service at temperatures up to 1200 K, with service times to 100,000 h or more. Therefore, long term microstructural stability is also being screened.

  14. Creep Property Characterization of Potential Brayton Cycle Impeller and Duct Materials

    Science.gov (United States)

    Gabb, Timothy P.; Gayda, john; Garg, Anita

    2007-01-01

    Cast superalloys have potential applications in space as impellers within closed-loop Brayton cycle nuclear power generation systems. Likewise wrought superalloys are good candidates for ducts and heat exchangers transporting the inert working gas in a Brayton-based power plant. Two cast superalloys, Mar-M247LC and IN792, and a NASA GRC powder metallurgy superalloy, LSHR, have been screened to compare their respective capabilities for impeller applications. Mar-M247LC has been selected for additional long term evaluations. Initial tests in helium indicate this inert environment may debit long term creep resistance of this alloy. Several wrought superalloys including Hastelloy(Registered TradeMark) X, Inconel(Registered TradeMark) 617, Inconel(Registered TradeMark) 740, Nimonic(Registered TradeMark) 263, Incoloy(Registered TradeMark) MA956, and Haynes 230 are also being screened to compare their capabilities for duct applications. Haynes 230 has been selected for additional long term evaluations. Initial tests in helium are just underway for this alloy. These proposed applications would require sufficient strength and creep resistance for long term service at temperatures up to 1200 K, with service times to 100,000 h or more. Therefore, long term microstructural stability is also being screened.

  15. Tensile and Creep Property Characterization of Potential Brayton Cycle Impeller and Duct Materials

    Science.gov (United States)

    Gabb, Timothy P.; Gayda, John

    2006-01-01

    This paper represents a status report documenting the work on creep of superalloys performed under Project Prometheus. Cast superalloys have potential applications in space as impellers within closed-loop Brayton cycle nuclear power generation systems. Likewise wrought superalloys are good candidates for ducts and heat exchangers transporting the inert working gas in a Brayton-based power plant. Two cast superalloys, Mar-M247LC and IN792, and a NASA GRC powder metallurgy superalloy, LSHR, are being screened to compare their respective capabilities for impeller applications. Several wrought superalloys including Hastelloy X, (Haynes International, Inc., Kokomo, IN), Inconel 617, Inconel 740, Nimonic 263, and Incoloy MA956 (Special Metals Corporation, Huntington, WV) are also being screened to compare their capabilities for duct applications. These proposed applications would require sufficient strength and creep resistance for long term service at temperatures up to 1200 K, with service times to 100,000 h or more. Conventional tensile and creep tests were performed at temperatures up to 1200 K on specimens extracted from the materials. Initial microstructure evaluations were also undertaken.

  16. Influence of irreversible losses on the performance of a two-stage magnetic Brayton refrigeration cycle

    International Nuclear Information System (INIS)

    The general performance characteristics of a two-stage magnetic Brayton refrigeration cycle consisting of three constant magnetic fields and three irreversible adiabatic processes are investigated. Based on the thermodynamic properties of a magnetic material and the irreversible cycle model of a two-stage Brayton refrigerator, expressions for the cooling load and coefficient of performance of the refrigeration system are derived. The influence of the finite-rate heat transfer in the heat exchange processes, irreversibilities in the three adiabatic processes, ratios of two magnetic fields in the three constant magnetic field processes, and heat leak losses between two heat reservoirs on the performance of the two-stage magnetic Brayton refrigeration cycle are analyzed in detail. Some important performance curves, which can reveal the general characteristics of the refrigeration system, are presented and the maximum values of cooling load and coefficient of performance are numerically calculated. The optimal choices and matches of other parameters at the maximum cooling load or the maximum coefficient of performance are discussed and the optimally operating regions of some important parameters in the refrigeration system are determined. The results obtained here are compared with those derived from other models of the magnetic Brayton refrigeration cycles, and consequently, the advantage of an inter-cooled process is expounded.

  17. Optimal analysis on the performance of an irreversible harmonic quantum Brayton refrigeration cycle.

    Science.gov (United States)

    Lin, Bihong; Chen, Jincan

    2003-11-01

    An irreversible model of a quantum refrigeration cycle working with many noninteracting harmonic oscillators is established. The refrigeration cycle consists of two adiabatic and two constant-frequency processes. The general performance characteristics of the cycle are investigated, based on the quantum master equation and the semigroup approach. The expressions for several important performance parameters such as the coefficient of performance, cooling rate, power input, and rate of entropy production are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of temperatures of the working substance and times spent on the two constant-frequency processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is compared with that of a classical Brayton refrigerator working with an ideal gas. The results obtained here show that in the high-temperature limit a harmonic quantum Brayton cycle may be equivalent to a classical Brayton cycle. PMID:14682856

  18. High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

    Science.gov (United States)

    Juhasz, Albert J.; Sawicki, Jerzy T.

    2003-01-01

    For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a partial energy conversion system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

  19. Dynamic Modeling and Control of Nuclear Reactors Coupled to Closed-Loop Brayton Cycle Systems using SIMULINKTM

    International Nuclear Information System (INIS)

    The operation of space reactors for both in-space and planetary operations will require unprecedented levels of autonomy and control. Development of these autonomous control systems will require dynamic system models, effective control methodologies, and autonomous control logic. This paper briefly describes the results of reactor, power-conversion, and control models that are implemented in SIMULINKTM (Simulink, 2004). SIMULINKTM is a development environment packaged with MatLabTM (MatLab, 2004) that allows the creation of dynamic state flow models. Simulation modules for liquid metal, gas cooled reactors, and electrically heated systems have been developed, as have modules for dynamic power-conversion components such as, ducting, heat exchangers, turbines, compressors, permanent magnet alternators, and load resistors. Various control modules for the reactor and the power-conversion shaft speed have also been developed and simulated. The modules are compiled into libraries and can be easily connected in different ways to explore the operational space of a number of potential reactor, power-conversion system configurations, and control approaches. The modularity and variability of these SIMULINKTM models provides a way to simulate a variety of complete power generation systems. To date, both Liquid Metal Reactors (LMR), Gas Cooled Reactors (GCR), and electric heaters that are coupled to gas-dynamics systems and thermoelectric systems have been simulated and are used to understand the behavior of these systems. Current efforts are focused on improving the fidelity of the existing SIMULINKTM modules, extending them to include isotopic heaters, heat pipes, Stirling engines, and on developing state flow logic to provide intelligent autonomy. The simulation code is called RPC-SIM (Reactor Power and Control-Simulator)

  20. Optimum criteria of an irreversible quantum Brayton refrigeration cycle with an ideal Bose gas

    International Nuclear Information System (INIS)

    An irreversible cycle model of the quantum Brayton refrigeration cycle is established, in which finite-time processes and irreversibility in the two adiabatic processes are taken into account. On the basis of the thermodynamic properties of an ideal Bose gas, by using the optimal control-theory, the mathematical expressions for several important performance parameters, such as the coefficient of performance, power input and cooling load, are derived and some important performance parameters, e.g., the temperatures of the working substance at several important state-points, are optimized. By means of numerical predictions, the optimal performance characteristic curves of a Bose-Brayton refrigeration cycle are obtained and analyzed. Furthermore, some optimal operating regions including those for the cooling load, coefficient of performance and the temperatures of the cyclic working substance at the two important state-points are determined and evaluated. Finally, several special cases are discussed in detail

  1. DIPS power conversion cycle selection

    International Nuclear Information System (INIS)

    This paper presents the results of the dynamic power conversion cycle selection process conducted by the Rocketdyne Division of Rockwell International as part of the Dynamic Isotope Power Subsystem (DIPS) Program, sponsored by the U.S. Department of Energy (DOE). Rocketdyne is under contract with DOE for the DIPS Program. The objective of the DIPS Program is to demonstrate the technology necessary to provide dynamic radioisotope space electrical power systems in the 1 to 10 kWe range to support evolving military and civilian missions in the early 1990s and beyond. Selecting the most appropriate DIPS power conversion cycle that would support this objective was an integral step in this process. The closed Brayton cycle was selected as the preferred power conversion cycle for the DIPS Program based on an evaluation of several key areas concerning spacecraft power systems performance

  2. Diagnostic system for combine cycle power plant

    International Nuclear Information System (INIS)

    We developed the Diagnostic System for Combined Cycle Power Plant which enables inexperienced operators as well as experienced operators to cope with abnormal conditions of Combined Cycle Power Plant. The features of this system are the Estimate of Emergency Level for Operation and the Prediction of Subsequent Abnormality, adding to the Diagnosis of Cause and the Operation Guidance. Moreover in this system, Diagnosis of Cause was improved by using our original method and support screens can be displayed for educational means in normal condition as well. (Authors)

  3. Optimum performance of the small-scale open and direct solar thermal Brayton cycle at various environmental conditions and constraints

    International Nuclear Information System (INIS)

    The Brayton cycle's heat source can be obtained from solar energy instead of the combustion of fuel. The irreversibilities of the open and direct solar thermal Brayton cycle with recuperator are mainly due to heat transfer across a finite temperature difference and fluid friction, which limit the net power output of such a system. In this work, the method of total entropy generation minimisation is applied to optimise the geometries of the receiver and recuperator at various steady-state weather conditions. For each steady-state weather condition, the optimum turbine operating point is also found. The authors specifically investigate the effect of wind and solar irradiance on the maximum net power output of the system. The effects of other conditions and constraints, on the maximum net power output, are also investigated. These include concentrator error, concentrator reflectivity and maximum allowable surface temperature of the receiver. Results show how changed solar beam irradiance and wind speed affect the system net power output and optimum operating point of the micro-turbine. A dish concentrator with fixed focal length, an off-the-shelf micro-turbine and a modified cavity receiver is considered. -- Highlights: ► An off-the-shelf micro-turbine and a modified cavity receiver are considered. ► We investigate the optimum operating point of micro-turbine in various situations. ► Optimum mass flow rate and exhaust temperature increase with beam irradiance. ► Optimum exhaust temperature increases as wind speed increases.

  4. Coupling a Supercritical Carbon Dioxide Brayton Cycle to a Helium-Cooled Reactor.

    Energy Technology Data Exchange (ETDEWEB)

    Middleton, Bobby [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pasch, James Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kruizenga, Alan Michael [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Walker, Matthew [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2016-01-01

    This report outlines the thermodynamics of a supercritical carbon dioxide (sCO2) recompression closed Brayton cycle (RCBC) coupled to a Helium-cooled nuclear reactor. The baseline reactor design for the study is the AREVA High Temperature Gas-Cooled Reactor (HTGR). Using the AREVA HTGR nominal operating parameters, an initial thermodynamic study was performed using Sandia's deterministic RCBC analysis program. Utilizing the output of the RCBC thermodynamic analysis, preliminary values of reactor power and of Helium flow rate through the reactor were calculated in Sandia's HelCO2 code. Some research regarding materials requirements was then conducted to determine aspects of corrosion related to both Helium and to sCO2 , as well as some mechanical considerations for pressures and temperatures that will be seen by the piping and other components. This analysis resulted in a list of materials-related research items that need to be conducted in the future. A short assessment of dry heat rejection advantages of sCO2> Brayton cycles was also included. This assessment lists some items that should be investigated in the future to better understand how sCO2 Brayton cycles and nuclear can maximally contribute to optimizing the water efficiency of carbon free power generation

  5. Design of organic Rankine cycle power systems accounting for expander performance

    DEFF Research Database (Denmark)

    La Seta, Angelo; Andreasen, Jesper Graa; Pierobon, Leonardo;

    2015-01-01

    Organic Rankine cycle power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. Its design process and efficiency estimation are particularly challenging due to...... the peculiar physical properties of the working fluid and the gasdynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders have to deal with small enthalpy drops and large expansion ratios. These features yield turbine designs with few highly......-loaded stages in supersonic flow regimes. This paper proposes a design method where the conventional cycle analysis is combined with calculations of the maximum expander performance using a validated mean-line design tool. The high computational cost of the turbine optimization is tackled building a model which...

  6. Operating conditions of an open and direct solar thermal Brayton cycle with optimised cavity receiver and recuperator

    International Nuclear Information System (INIS)

    The small-scale open and direct solar thermal Brayton cycle with recuperator has several advantages, including low cost, low operation and maintenance costs and it is highly recommended. The main disadvantages of this cycle are the pressure losses in the recuperator and receiver, turbomachine efficiencies and recuperator effectiveness, which limit the net power output of such a system. The irreversibilities of the solar thermal Brayton cycle are mainly due to heat transfer across a finite temperature difference and fluid friction. In this paper, thermodynamic optimisation is applied to concentrate on these disadvantages in order to optimise the receiver and recuperator and to maximise the net power output of the system at various steady-state conditions, limited to various constraints. The effects of wind, receiver inclination, rim angle, atmospheric temperature and pressure, recuperator height, solar irradiance and concentration ratio on the optimum geometries and performance were investigated. The dynamic trajectory optimisation method was applied. Operating points of a standard micro-turbine operating at its highest compressor efficiency and a parabolic dish concentrator diameter of 16 m were considered. The optimum geometries, minimum irreversibility rates and maximum receiver surface temperatures of the optimised systems are shown. For an environment with specific conditions and constraints, there exists an optimum receiver and recuperator geometry so that the system produces maximum net power output. -- Highlights: → Optimum geometries exist such that the system produces maximum net power output. → Optimum operating conditions are shown. → Minimum irreversibility rates and minimum entropy generation rates are shown. → Net power output was described in terms of total entropy generation rate. → Effects such as wind, recuperator height and irradiance were investigated.

  7. Solar/gas Brayton/Rankine cycle heat pump assessment

    Science.gov (United States)

    Rousseau, J.; Liu, A. Y.

    1982-05-01

    A 10-ton gas-fired heat pump is currently under development at AiResearch under joint DOE and GRI sponsorship. This heat pump features a highly efficient, recuperated, subatmospheric Brayton-cycle engine which drives the centrifugal compressor of a reversible vapor compression heat pump. The investigations under this program were concerned initially with the integration of this machine with a parabolic dish-type solar collector. Computer models were developed to accurately describe the performance of the heat pump packaged in this fashion. The study determined that (1) only a small portion (20 to 50 percent) of the available solar energy could be used because of a fundamental mismatch between the heating and cooling demand and the availability of solar energy, and (2) the simple pay back period, by comparison to the baseline non-solar gas-fired heat pump, was unacceptable (15 to 36 years).

  8. Conceptual Design of S-CO{sub 2} Brayton Cycle Radial Turbomachinery for KAIST Micro Modular Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seongkuk; Kim, Seong Gu; Lee, Jekyoung; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    KAIST proposed a new SMR design, which utilizes S-CO{sub 2} as the working fluid. It was named as KAIST MMR. Compared with existing SMR concepts, KAIST MMR has advantages of achieving smaller volume of power conversion unit (PCU) and containing the core and PCU in one vessel for the complete modularization. Authors noticed that the compressor and turbine assumed performances of KAIST MMR were conservatively selected previously. Thus, this paper tries to address the best estimate values of each turbomachinery in 10MWe class KAIST MMR. The turbomachinery size of the S-CO{sub 2} cycle is smaller than helium Brayton cycle and steam Rankine cycle. The suggested SMR concept adopts passive cooling system by using air. This method can cool reactor without external electricity supply. Small size and more flexible installation in the inland area will be necessary characteristics for the future nuclear application in the water limited region. KAIST MMR meets all these requirements by utilizing S-CO{sub 2} as a working fluid. This paper presents the work for further increasing the system performance by estimating the component efficiency more realistically. The cycle layout adopted for the application is S-CO{sub 2} recuperated Brayton cycle. The best efficiency of compressor and turbine was evaluated to be 84.94% and 90.94%, respectively. By using KAIST in-house code, thermal efficiency and net output were increased to 35.81% and 12.45MWe, respectively, for the same core thermal power. More refined cycle layout and suitable turbomachinery design will be performed in the near future.

  9. A Closed Brayton Power Conversion Unit Concept for Nuclear Electric Propulsion for Deep Space Missions

    Science.gov (United States)

    Joyner, Claude Russell; Fowler, Bruce; Matthews, John

    2003-01-01

    In space, whether in a stable satellite orbit around a planetary body or traveling as a deep space exploration craft, power is just as important as the propulsion. The need for power is especially important for in-space vehicles that use Electric Propulsion. Using nuclear power with electric propulsion has the potential to provide increased payload fractions and reduced mission times to the outer planets. One of the critical engineering and design aspects of nuclear electric propulsion at required mission optimized power levels is the mechanism that is used to convert the thermal energy of the reactor to electrical power. The use of closed Brayton cycles has been studied over the past 30 or years and shown to be the optimum approach for power requirements that range from ten to hundreds of kilowatts of power. It also has been found to be scalable to higher power levels. The Closed Brayton Cycle (CBC) engine power conversion unit (PCU) is the most flexible for a wide range of power conversion needs and uses state-of-the-art, demonstrated engineering approaches. It also is in use with many commercial power plants today. The long life requirements and need for uninterrupted operation for nuclear electric propulsion demands high reliability from a CBC engine. A CBC engine design for use with a Nuclear Electric Propulsion (NEP) system has been defined based on Pratt & Whitney's data from designing long-life turbo-machines such as the Space Shuttle turbopumps and military gas turbines and the use of proven integrated control/health management systems (EHMS). An integrated CBC and EHMS design that is focused on using low-risk and proven technologies will over come many of the life-related design issues. This paper will discuss the use of a CBC engine as the power conversion unit coupled to a gas-cooled nuclear reactor and the design trends relative to its use for powering electric thrusters in the 25 kWe to 100kWe power level.

  10. A closed Brayton power conversion unit concept for nuclear electric propulsion for deep space missions

    International Nuclear Information System (INIS)

    In space, whether in a stable satellite orbit around a planetary body or traveling as a deep space exploration craft, power is just as important as the propulsion. The need for power is especially important for in-space vehicles that use Electric Propulsion. Using nuclear power with electric propulsion has the potential to provide increased payload fractions and reduced mission times to the outer planets. One of the critical engineering and design aspects of nuclear electric propulsion at required mission optimized power levels is the mechanism that is used to convert the thermal energy of the reactor to electrical power. The use of closed Brayton cycles has been studied over the past 30 or years and shown to be the optimum approach for power requirements that range from ten to hundreds of kilowatts of power. It also has been found to be scalable to higher power levels. The Closed Brayton Cycle (CBC) engine power conversion unit (PCU) is the most flexible for a wide range of power conversion needs and uses state-of-the-art, demonstrated engineering approaches. It also is in use with many commercial power plants today. The long life requirements and need for uninterrupted operation for nuclear electric propulsion demands high reliability from a CBC engine. A CBC engine design for use with a Nuclear Electric Propulsion (NEP) system has been defined based on Pratt and Whitney's data from designing long-life turbo-machines such as the Space Shuttle turbopumps and military gas turbines and the use of proven integrated control/health management systems (EHMS). An integrated CBC and EHMS design that is focused on using low-risk and proven technologies will over come many of the life-related design issues. This paper will discuss the use of a CBC engine as the power conversion unit coupled to a gas-cooled nuclear reactor and the design trends relative to its use for powering electric thrusters in the 25 kWe to 100kWe power level

  11. An Advanced Light Weight Recuperator for Space Power Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Closed Brayton Cycle (CBC) space power system is one of the most efficient energy conversion technologies for nuclear and solar electric propulsion. The recuperator...

  12. Features of supercritical carbon dioxide Brayton cycle coupled with reactor

    International Nuclear Information System (INIS)

    In order to obtain acceptable cycle efficiency, current helium gas turbine power cycle technology needs high cycle temperature which means that the cycle needs high core-out temperature. The technology has high requirements on reactor structure and fuel elements materials, and also on turbine manufacture. While utilizing CO2 as cycle working fluid, it can guarantee to lower the cycle temperature and turbo machine Janume but achieve the same cycle efficiency, so as to enhance the safety and economy of reactor. According to the laws of thermodynamics, a calculation model of supercritical CO2 power cycle was established to analyze the feature, and the decisive parameters of the cycle and also investigate the effect of each parameter on the cycle efficiency in detail were obtained. The results show that supercritical CO2 power cycle can achieve quite satisfied efficiency at a lower cycle highest temperature than helium cycle, and CO2 is a promising working fluid. (authors)

  13. Thermodynamic analysis of a Brayton cycle and Rankine cycle arranged in series exploiting the cold exergy of LNG (liquefied natural gas)

    International Nuclear Information System (INIS)

    The LNG (liquefied natural gas) regasification process is a source of cold exergy capable of being exploited to improve the efficiency of energy conversion. This paper presents a novel power plant consisting of a combination of a CBC (closed Brayton cycle) with a SRC (steam Rankine cycle), arranged in series with regard to the power source, while exploiting the cold exergy available in the regasification process of LNG. The power plant is fuelled by a combustion system of natural gas where the flue gases firstly yield heat to the CBC, then to the SRC and finally to the combustion air by means of a heat recovery process. The LNG cold exergy is exploited to cool the He used in the CBC to cryogenic temperatures at the compressor inlet as well as for generating electric power through direct expansion. The power plant is thermodynamically modelled and simulated using EES (Engineering Equation Solver). An energy and exergy analysis is carried out to evaluate the effect of some key parameters on the efficiency such as the temperature at the compressor inlet, the compression ratio, the temperature at the CBC turbine inlet and the LNG pressure during the regasification process. The outcome is a high efficiency power plant. - Highlights: • A closed Brayton cycle and a steam Rankine cycle arranged in series. • Exploitation of LNG cold exergy to increase power plant efficiency. • Thermodynamic analysis to evaluate the effect of the key parameters on the efficiency. • Energy and exergy efficiency of the power plant is respectively 56.72% and 55.09%. • The exergy available in the LNG represents 20.34% of the fuel exergy

  14. Advanced thermal-energy-storage concept-definition study for solar Brayton power plants. Final technical report, Volume I

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    The detailed results are presented of a technical and economic assessment of phase change and thermochemical energy storage systems in a solar power plant employing a high temperature Brayton cycle thermal engine with helium as the heat transport fluid. The assessment included an examination of the storage system operation, efficiency, power plant interaction, design, materials, safety, maintenance, environmental impact, system life, and economics. These considerations are implemented in the conceptual design of three baseline storage systems and their components for use in a solar power plant module of 50 megawatt electrical power output. Rationale is provided to support the configuration, operation and material choices. A preliminary assessment of the technology development and experimental test program requirements are also included. The report is contained in four separate volumes. This volume is the technical report.

  15. Modeling the small-scale dish-mounted solar thermal Brayton cycle

    Science.gov (United States)

    Le Roux, Willem G.; Meyer, Josua P.

    2016-05-01

    The small-scale dish-mounted solar thermal Brayton cycle (STBC) makes use of a sun-tracking dish reflector, solar receiver, recuperator and micro-turbine to generate power in the range of 1-20 kW. The modeling of such a system, using a turbocharger as micro-turbine, is required so that optimisation and further development of an experimental setup can be done. As a validation, an analytical model of the small-scale STBC in Matlab, where the net power output is determined from an exergy analysis, is compared with Flownex, an integrated systems CFD code. A 4.8 m diameter parabolic dish with open-cavity tubular receiver and plate-type counterflow recuperator is considered, based on previous work. A dish optical error of 10 mrad, a tracking error of 1° and a receiver aperture area of 0.25 m × 0.25 m are considered. Since the recuperator operates at a very high average temperature, the recuperator is modeled using an updated ɛ-NTU method which takes heat loss to the environment into consideration. Compressor and turbine maps from standard off-the-shelf Garrett turbochargers are used. The results show that for the calculation of the steady-state temperatures and pressures, there is good comparison between the Matlab and Flownex results (within 8%) except for the recuperator outlet temperature, which is due to the use of different ɛ-NTU methods. With the use of Matlab and Flownex, it is shown that the small-scale open STBC with an existing off-the-shelf turbocharger could generate a positive net power output with solar-to-mechanical efficiency of up to 12%, with much room for improvement.

  16. Conceptual design study of a 5 kilowatt solar dynamic Brayton power system using a dome Fresnel lens solar concentrator

    Science.gov (United States)

    Oneill, Mark J.; Mcdanal, A. J.; Spears, Don H.

    1989-01-01

    The primary project objective was to generate a conceptual design for a nominal 5 kW solar dynamic space power system, which uses a unique, patented, transmittance-optimized, dome-shaped, point-focus Fresnel lens as the optical concentrator. Compared to reflective concentrators, the dome lens allows 200 times larger slope errors for the same image displacement. Additionally, the dome lens allows the energy receiver, the power conversion unit (PCU), and the heat rejection radiator to be independently optimized in configuration and orientation, since none of these elements causes any aperture blockage. Based on optical and thermal trade studies, a 6.6 m diameter lens with a focal length of 7.2 m was selected. This lens should provide 87 percent net optical efficienty at 800X geometric concentration ratio. The large lens is comprised of 24 gores, which compactly stow together during launch, and automatically deploy on orbit. The total mass of the microglass lens panels, the graphite/epoxy support structure, and miscellaneous hardware is about 1.2 kg per square meter of aperture. The key problem for the dome lens approach relates to the selection of a space-durable lens material. For the first time, all-glass Fresnel lens samples were successfully made by a sol-gel casting process.

  17. Exergetic efficiency optimization for an irreversible heat pump working on reversed Brayton cycle

    Indian Academy of Sciences (India)

    Yuehong Bi; Lingen Chen; Fengrui Sun

    2010-03-01

    This paper deals with the performance analysis and optimization for irreversible heat pumps working on reversed Brayton cycle with constant-temperature heat reservoirs by taking exergetic efficiency as the optimization objective combining exergy concept with finite-time thermodynamics (FTT). Exergetic efficiency is defined as the ratio of rate of exergy output to rate of exergy input of the system. The irreversibilities considered in the system include heat resistance losses in the hot- and cold-side heat exchangers and non-isentropic losses in the compression and expansion processes. The analytical formulas of the heating load, coefficient of performance (COP) and exergetic efficiency for the heat pumps are derived. The results are compared with those obtained for the traditional heating load and coefficient of performance objectives. The influences of the pressure ratio of the compressor, the allocation of heat exchanger inventory, the temperature ratio of two reservoirs, the effectiveness of the hot- and cold-side heat exchangers and regenerator, the efficiencies of the compressor and expander, the ratio of hot-side heat reservoir temperature to ambient temperature, the total heat exchanger inventory, and the heat capacity rate of the working fluid on the exergetic efficiency of the heat pumps are analysed by numerical calculations. The results show that the exergetic efficiency optimization is an important and effective criterion for the evaluation of an irreversible heat pump working on reversed Brayton cycle.

  18. Use of RELAP5-3D for Dynamic Analysis of a Closed-Loop Brayton Cycle Coupled To a Nuclear Reactor

    International Nuclear Information System (INIS)

    This paper describes results of a dynamic system model for a pair of closed Brayton-cycle (CBC) loops running in parallel that are connected to a nuclear gas reactor. The model assumes direct coupling between the reactor and the Brayton-cycle loops. The RELAP5-3D (version 2.4.1) computer program was used to perform the analysis. Few reactors have ever been coupled to closed Brayton-cycle systems. As such their behavior under dynamically varying loads, startup and shut down conditions, and requirements for safe and autonomous operation are largely unknown. The model described in this paper represents the reactor, turbine, compressor, recuperator, heat rejection system and alternator. The initial results of the model indicate stable operation of the reactor-driven Brayton-cycle system. However, for analysts with mostly pressurized water reactor experience, the Brayton cycle loops coupled to a gas-cooled reactor also indicate some counter-intuitive behavior for the complete coupled system. This model has provided crucial information in evaluating the reactor design and would have been further developed for use in developing procedures for safe start up, shut down, safe-standby, and other autonomous operating modes had the plant development cycle been completed

  19. Dynamic response simulation for high temperature gas-cooled reactor with indirect closed Brayton cycle

    International Nuclear Information System (INIS)

    A transient simulation program is developed in order to study dynamic characteristics of high temperature gas-cooled reactor with indirect closed Brayton cycle. After the brief introduction to such a plant, detailed mathematical models for important installations are described in the paper. By inducing step positive reactivity into the reactor, it looks like that the powers of turbo machine installations have a different growth rate accompanied with small increase of reactor power. Furthermore, this paper shows the temperature changes of reactor and heat exchangers. For the heat exchangers of the whole secondary loop, the pressure changes behave quite differently for those three sections divided by turbine, low pressure compressor and high pressure compressor. For all these equipments, the simulation program gives reasonable results and is in accordance with dynamic characteristics of their own. (authors)

  20. Comparison of Direct and Indirect Gas Reactor Brayton Systems for Nuclear Electric Space Propulsion

    International Nuclear Information System (INIS)

    Gas reactor systems are being considered as candidates for use in generating power for the Prometheus-1 spacecraft, along with other NASA missions as part of the Prometheus program. Gas reactors offer a benign coolant, which increases core and structural materials options. However, the gas coolant has inferior thermal transport properties, relative to other coolant candidates such as liquid metals. This leads to concerns for providing effective heat transfer and for minimizing pressure drop within the reactor core. In direct gas Brayton systems, i.e. those with one or more Brayton turbines in the reactor cooling loop, the ability to provide effective core cooling and low pressure drop is further constrained by the need for a low pressure, high molecular weight gas, typically a mixture of helium and xenon. Use of separate primary and secondary gas loops, one for the reactor and one or more for the Brayton system(s) separated by heat exchanger(s), allows for independent optimization of the pressure and gas composition of each loop. The reactor loop can use higher pressure pure helium, which provides improved heat transfer and heat transport properties, while the Brayton loop can utilize lower pressure He-Xe. However, this approach requires a separate primary gas circulator and also requires gas to gas heat exchangers. This paper focuses on the trade-offs between the direct gas reactor Brayton system and the indirect gas Brayton system. It discusses heat exchanger arrangement and materials options and projects heat exchanger mass based on heat transfer area and structural design needs. Analysis indicates that these heat exchangers add considerable mass, but result in reactor cooling and system resiliency improvements

  1. Exergy Analysis and Second Law Efficiency of a Regenerative Brayton Cycle with Isothermal Heat Addition

    Directory of Open Access Journals (Sweden)

    Naser M. Jubeh

    2005-07-01

    Full Text Available Abstract: The effect of two heat additions, rather than one, in a gas turbine engine is analyzed from the second law of thermodynamics point of view. A regenerative Brayton cycle model is used for this study, and compared with other models of Brayton cycle. All fluid friction losses in the compressor and turbine are quantified by an isentropic efficiency term. The effect of pressure ratio, turbine inlet temperature, ambient temperature, altitude, and altitude with variable ambient temperature on irreversibility "exergy destroyed" and second law efficiency was investigated and compared for all models. The results are given graphically with the appropriate discussion and conclusion.

  2. Power Systems Life Cycle Analysis Tool (Power L-CAT).

    Energy Technology Data Exchange (ETDEWEB)

    Andruski, Joel; Drennen, Thomas E.

    2011-01-01

    The Power Systems L-CAT is a high-level dynamic model that calculates levelized production costs and tracks environmental performance for a range of electricity generation technologies: natural gas combined cycle (using either imported (LNGCC) or domestic natural gas (NGCC)), integrated gasification combined cycle (IGCC), supercritical pulverized coal (SCPC), existing pulverized coal (EXPC), nuclear, and wind. All of the fossil fuel technologies also include an option for including carbon capture and sequestration technologies (CCS). The model allows for quick sensitivity analysis on key technical and financial assumptions, such as: capital, O&M, and fuel costs; interest rates; construction time; heat rates; taxes; depreciation; and capacity factors. The fossil fuel options are based on detailed life cycle analysis reports conducted by the National Energy Technology Laboratory (NETL). For each of these technologies, NETL's detailed LCAs include consideration of five stages associated with energy production: raw material acquisition (RMA), raw material transport (RMT), energy conversion facility (ECF), product transportation and distribution (PT&D), and end user electricity consumption. The goal of the NETL studies is to compare existing and future fossil fuel technology options using a cradle-to-grave analysis. The NETL reports consider constant dollar levelized cost of delivered electricity, total plant costs, greenhouse gas emissions, criteria air pollutants, mercury (Hg) and ammonia (NH3) emissions, water withdrawal and consumption, and land use (acreage).

  3. Thermodynamic analysis of the double Brayton cycle with the use of oxy combustion and capture of CO2

    Science.gov (United States)

    Ziółkowski, Paweł; Zakrzewski, Witold; Kaczmarczyk, Oktawia; Badur, Janusz

    2013-06-01

    In this paper, thermodynamic analysis of a proposed innovative double Brayton cycle with the use of oxy combustion and capture of CO2, is presented. For that purpose, the computation flow mechanics (CFM) approach has been developed. The double Brayton cycle (DBC) consists of primary Brayton and secondary inverse Brayton cycle. Inversion means that the role of the compressor and the gas turbine is changed and firstly we have expansion before compression. Additionally, the workingfluid in the DBC with the use of oxy combustion and CO2 capture contains a great amount of H2O and CO2, and the condensation process of steam (H2O) overlaps in negative pressure conditions. The analysis has been done for variants values of the compression ratio, which determines the lowest pressure in the double Brayton cycle.

  4. Investigation of plant control strategies for the supercritical C02Brayton cycle for a sodium-cooled fast reactor using the plant dynamics code

    International Nuclear Information System (INIS)

    The development of a control strategy for the supercritical CO2 (S-CO2) Brayton cycle has been extended to the investigation of alternate control strategies for a Sodium-Cooled Fast Reactor (SFR) nuclear power plant incorporating a S-CO2 Brayton cycle power converter. The SFR assumed is the 400 MWe (1000 MWt) ABR-1000 preconceptual design incorporating metallic fuel. Three alternative idealized schemes for controlling the reactor side of the plant in combination with the existing automatic control strategy for the S-CO2 Brayton cycle are explored using the ANL Plant Dynamics Code together with the SAS4A/SASSYS-1 Liquid Metal Reactor (LMR) Analysis Code System coupled together using the iterative coupling formulation previously developed and implemented into the Plant Dynamics Code. The first option assumes that the reactor side can be ideally controlled through movement of control rods and changing the speeds of both the primary and intermediate coolant system sodium pumps such that the intermediate sodium flow rate and inlet temperature to the sodium-to-CO2 heat exchanger (RHX) remain unvarying while the intermediate sodium outlet temperature changes as the load demand from the electric grid changes and the S-CO2 cycle conditions adjust according to the S-CO2 cycle control strategy. For this option, the reactor plant follows an assumed change in load demand from 100 to 0 % nominal at 5 % reduction per minute in a suitable fashion. The second option allows the reactor core power and primary and intermediate coolant system sodium pump flow rates to change autonomously in response to the strong reactivity feedbacks of the metallic fueled core and assumed constant pump torques representing unchanging output from the pump electric motors. The plant behavior to the assumed load demand reduction is surprising close to that calculated for the first option. The only negative result observed is a slight increase in the intermediate inlet sodium temperatures by about 10 C

  5. Design of automatic startup and shutdown logic for a Brayton-cycle 2- to 15-kilowatt engine

    Science.gov (United States)

    Vrancik, J. E.; Bainbridge, R. C.

    1975-01-01

    The NASA Lewis Research Center is conducting a closed-Brayton-cycle power conversion system technology program in which a complete power system (engine) has been designed and demonstrated. This report discusses the design of automatic startup and shutdown logic circuits as a modification to the control system presently used in this demonstration engine. This modification was primarily intended to make starting the engine as simple and safe as possible and to allow the engine to be run unattended. In the modified configuration the engine is started by turning the control console power on and pushing the start button after preheating the gas loop. No other operator action is required to effect a complete startup. Shutdown, if one is required, is also effected by a simple stop button. The automatic startup and shutdown of the engine have been successfully and purposefully demonstrated more than 50 times at the Lewis Research Center during 10,000 hours of unattended operation. The net effect of this modification is an engine that can be safely started and stopped by relatively untrained personnel. The approach lends itself directly to remote unattended operation.

  6. Development of a Supercritical Carbon Dioxide Brayton Cycle: Improving VHTR Efficiency and Testing Material Compatibility - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Chang H. Oh

    2006-06-01

    Generation IV reactors will need to be intrinsically safe, having a proliferation-resistant fuel cycle and several advantages relative to existing light water reactor (LWR). They, however, must still overcome certain technical issues and the cost barrier before it can be built in the U.S. The establishment of a nuclear power cost goal of 3.3 cents/kWh is desirable in order to compete with fossil combined-cycle, gas turbine power generation. This goal requires approximately a 30 percent reduction in power cost for stateof-the-art nuclear plants. It has been demonstrated that this large cost differential can be overcome only by technology improvements that lead to a combination of better efficiency and more compatible reactor materials. The objectives of this research are (1) to develop a supercritical carbon dioxide Brayton cycle in the secondary power conversion side that can be applied to the Very-High-Temperature Gas-Cooled Reactor (VHTR), (2) to improve the plant net efficiency by using the carbon dioxide Brayton cycle, and (3) to test material compatibility at high temperatures and pressures. The reduced volumetric flow rate of carbon dioxide due to higher density compared to helium will reduce compression work, which eventually increase plant net efficiency.

  7. Analysis of a 115MW, 3 shaft, helium Brayton cycle

    International Nuclear Information System (INIS)

    This research theme is originated from a development project that is going on in South Africa, for the design and construction of a closed cycle gas turbine plant using gas-cooled reactor as the heat source to generate 115 MW of electricity. South African Power utility company, Eskorn, promotes this developmental work through its subsidiary called PBMR (Pebble Bed Modular Reactor). Some of the attractive features of this plant are the inherent and passive safety features, modular geometry, small evacuation area, small infrastructure requirements for the installation and running of the plant, small construction time, quick starting and stopping and also low operational cost. This exercise is looking at the operational aspects of a closed cycle gas turbine, the finding of which will have a direct input towards the successful development and commissioning of the plant. A thorough understanding of the fluid dynamics in this three-shaft system and its transient performance analysis were the two main objectives of this research work. A computer programme called GTSI, developed by a previous Cranfield University research student, has been used in this as a base programme for the performance analysis. Some modifications were done on this programme to improve its control abilities. The areas covered in the performance analysis are Start-up, Shutdown and Load ramping. A detailed literature survey has been conducted to learn from the helium Turbo machinery experiences, though it is very limited. A critical analysis on the design philosophy of the PBMR is also carried out as part of this research work. The performance analysis has shown the advantage, disadvantage and impact of various power modulation methods suggested for the PBMR. It has tracked the effect of the operations of the various valves included in the PBMR design. The start-up using a hot gas injection has been analysed in detail and a successful start region has been mapped. A start-up procedure is also written

  8. Analysis of Superimposed Elementary Thermodynamic Cycles: from the Brayton-Joule to Advanced Mixed (Auto-Combined Cycles

    Directory of Open Access Journals (Sweden)

    Giovanni Manente

    2009-09-01

    Full Text Available

    The need for efficiency improvement in energy conversion systems leads to a stricter functional integration among system components. This results in structures of increasing complexity, the high performance of which are often difficult to be understood easily. To make the comprehension of these structures easier, a new approach is followed in this paper, consisting in their representation as partial or total superimposition of elementary thermodynamic cycles. Although system performance cannot, in general, be evaluated as the sum of the performance of the separate thermodynamic cycles, this kind of representation and analysis can be of great help in understanding directions of development followed in the literature for the construction of advanced energy systems, and could suggest new potential directions of work. The evolution from the simple Brayton-Joule cycle to the so called “mixed” cycles, in which heat at the turbine discharge is exploited using internal heat sinks only without using a separate bottoming section, is used to demonstrate the potentiality of the approach. Mixed cycles are named here "auto-combined cycles” to highlight the combination of different (gas and steam cycles within the same system components.

    • This paper is an updated version of a paper published in the ECOS'08 proceedings. 

  9. A novel nuclear combined power and cooling system integrating high temperature gas-cooled reactor with ammonia–water cycle

    International Nuclear Information System (INIS)

    Highlights: • We propose a novel nuclear ammonia–water power and cooling cogeneration system. • The high temperature reactor is inherently safe, with exhaust heat fully recovered. • The thermal performances are improved compared with nuclear combined cycle. • The base case attains an energy efficiency of 69.9% and exergy efficiency of 72.5%. • Energy conservation and emission reduction are achieved in this cogeneration way. - Abstract: A nuclear ammonia–water power and refrigeration cogeneration system (NAPR) has been proposed and analyzed in this paper. It consists of a closed high temperature gas-cooled reactor (HTGR) topping Brayton cycle and a modified ammonia water power/refrigeration combined bottoming cycle (APR). The HTGR is an inherently safe reactor, and thus could be stable, flexible and suitable for various energy supply situation, and its exhaust heat is fully recovered by the mixture of ammonia and water in the bottoming cycle. To reduce exergy losses and enhance outputs, the ammonia concentrations of the bottoming cycle working fluid are optimized in both power and refrigeration processes. With the HTGR of 200 MW thermal capacity and 900 °C/70 bar reactor-core-outlet helium, the system achieves 88.8 MW net electrical output and 9.27 MW refrigeration capacity, and also attains an energy efficiency of 69.9% and exergy efficiency of 72.5%, which are higher by 5.3%-points and 2.6%-points as compared with the nuclear combined cycle (NCC, like a conventional gas/steam power-only combined cycle while the topping cycle is a closed HTGR Brayton cycle) with the same nuclear energy input. Compared with conventional separate power and refrigeration generation systems, the fossil fuel saving (based on CH4) and CO2 emission reduction of base-case NAPR could reach ∼9.66 × 104 t/y and ∼26.6 × 104 t/y, respectively. The system integration accomplishes the safe and high-efficiency utilization of nuclear energy by power and refrigeration

  10. Off-design performance prediction of Radial Compressor of Supercritical CO2 Brayton Cycle for KAIST Micro Modular Reactor

    International Nuclear Information System (INIS)

    KAIST research team suggested a new concept of SMR, which utilizes S-CO2 as the operating fluid and coolant. It was named as KAIST MMR(Micro Modular Reactor). Compared with existing SMR concepts, this reactor has advantages of achieving smaller volume of power conversion unit (PCU) containing the core and PCU in one vessel for the complete modularization passive air-cooling system more flexible installation in the inland area. In previous study, performance of turbomachinery in PCU was considered only on-design. But, off-design performances of each component can affect not only PCU but also the core because this reactor adopts the direct S-CO2 loop in GFR. Nuclear system is applied by relatively conservative criteria of safety. Thus, off-design performances of each component should be considered in order to be more realistic reactor. The suggested turbomachinery size of the S-CO2 cycle is relatively smaller than those of helium Brayton cycle and steam Rankine cycle. Performance analysis of compressor is conducted by KAIST-TMD in case of on-design and off-design. Compressor efficiency in on-design conditions is obtained 84.51 %. But compressor performance in off-design conditions decreases certainly. This means that more heat than existing prediction is rejected by air-cooling system. KAIST-TMD will be verified with more experiment data for providing the results of more accurate analysis. Also, this code will be modified to couple with safety analysis codes and S-CO2 cycle analysis codes in the future. Furthermore, authors will consider aerodynamic performance analysis and various losses for more realization

  11. Power conversion system considerations for a high efficiency small modular nuclear gas turbine combined cycle power plant concept (NGTCC)

    International Nuclear Information System (INIS)

    The power conversion system (PCS) in the proposed small modular combined cycle nuclear gas turbine plant is based on the coupling of a non-intercooled topping helium Brayton direct closed-cycle gas turbine and a single-reheat supercritical steam Rankine bottoming cycle. The nuclear heat source (with a thermal rating of 350 MWt) is a helium cooled and graphite moderated very high temperature reactor (VHTR) embodying an assembly of prismatic fuel elements. Based on a reactor outlet (and gas turbine inlet) temperature of 95 °C, the module electrical power output is 180 MWe (50 and 130 MWe from the gas and steam turbines respectively) with an estimated plant efficiency of 51.5 percent. The design and development of the proposed nuclear gas turbine combined cycle (NGTCC) concept would benefit from established technology bases. With the inclusion of a process heat extraction module embodying a compact steam-to-steam re-boiler the proposed plant concept could operate in a cogeneration mode, namely generating electrical power plus providing a supply of uncontaminated process steam to various industrial users. This paper addresses projected HTR to VHTR plant evolution, thermodynamic cycle selection, plant performance, tentative arrangement of the combined cycle PCS, component design considerations and their technology bases, and major development requirements. The NGTCC is an advanced long-term helium cooled reactor concept, and a single module demonstration plant may be realizable by say circa 2030, this leading to commercial operation of multi-module plants, and paving the way for future very high temperature nuclear process heat plants in the middle decades of the 21st century. - Highlights: • Nuclear plant concept with very high temperature helium cooled reactor heat source. • Helium gas turbine and supercritical steam turbine power conversion system. • Modular plant concept power 180 MWe and projected efficiency 51.5 percent. • Cogeneration option with

  12. Ecological Optimization and Parametric Study of an Irreversible Regenerative Modified Brayton Cycle with Isothermal Heat Addition

    OpenAIRE

    Vivek Tiwari; Subhash Chandra Kaushik; Sudhir Kumar Tyagi

    2003-01-01

    Abstract: An ecological optimization along with a detailed parametric study of an irreversible regenerative Brayton heat engine with isothermal heat addition have been carried out with external as well as internal irreversibilities. The ecological function is defined as the power output minus the power loss (irreversibility) which is ambient temperature times the entropy generation rate. The external irreversibility is due to finite temperature difference between the heat engine and the exter...

  13. The Brayton Cycle heat pump for solvent recovery and pollution control

    International Nuclear Information System (INIS)

    The Brayton Cycle heat pump technology for the recovery of solvent and prevention of emissions is relatively new. Like most new technologies, it is a combination of older concepts, ideas and types of processes put together in a unique way. As a result, proven equipment enables achievement of extremely low condensing temperatures at relatively low cost. The Brayton Cycle is a thermodynamic principle. It was used first for a turbine engine, but more recently it has been used for a variety of other kinds of processes including refrigeration. A great variety of methods are used for emission control including adsorption, direct condensation, absorption in a fluid, and incineration or destruction. The Brayton Cycle technology actually fits into two of these categories, adsorption and direct condensation. Since it is a refrigeration process, it can be used to condense solvents from a solvent-laden air stream. The advantage of this particular process over other refrigeration methods is that lower temperatures can be achieved more easily. In fact, temperatures as low as -150 degrees F have been used to recover solvents in this manner. That happens to be the freezing point of methylene chloride which is a very volatile compound. High recovery efficiencies can be obtained for a whole variety of organic materials. 8 figs., 1 tab

  14. Optimization performance and thermodynamic analysis of an irreversible nano scale Brayton cycle operating with Maxwell–Boltzmann gas

    International Nuclear Information System (INIS)

    Highlights: • Performance analysis of irreversible nano scale Brayton cycle operating with Maxwell–Boltzmann gas is studied. • Multi-objective optimization approach is carried out for performance optimization. • 3 decision-making methods are employed to select final answers. - Abstract: In last decades, nano technology developed. Since, nano scale thermal cycles will be possibly employed in the near future. In this research, a nano scale irreversible Brayton cycle is investigated thermodynamically for optimizing the performance of the aforementioned cycle. Ideal Maxwell–Boltzmann gas is employed as a working fluid in the system. In this paper, two scenarios are employed in the multi-objective optimization process; however, the outcomes of each of the scenarios are evaluated independently. In the first scenario, in order to maximize the dimensionless Maximum available work and energy efficiency of the system, multi-objective optimization algorithms is employed. Furthermore, in the second scenario, two objective functions comprising the dimensionless Maximum available work and the dimensionless Ecological function are maximized concurrently via employing multi objective optimization algorithms. The multi objective evolutionary approaches on the basis of non-dominated sorting genetic algorithm method are employed in this paper. Decision making is done via three methods including linear programming techniques for multidimensional analysis of preference and Technique for order of preference by similarity to ideal solution and Bellman–Zadeh. Finally, error analysis is implemented on the results obtained from each scenario

  15. Fossil fuel combined cycle power system

    Science.gov (United States)

    Labinov, Solomon Davidovich; Armstrong, Timothy Robert; Judkins, Roddie Reagan

    2006-10-10

    A system for converting fuel energy to electricity includes a reformer for converting a higher molecular weight gas into at least one lower molecular weight gas, at least one turbine to produce electricity from expansion of at least one of the lower molecular weight gases, and at least one fuel cell. The system can further include at least one separation device for substantially dividing the lower molecular weight gases into at least two gas streams prior to the electrochemical oxidization step. A nuclear reactor can be used to supply at least a portion of the heat the required for the chemical conversion process.

  16. Optimum operation cycle of nuclear plant in power system operation

    International Nuclear Information System (INIS)

    Extension of nuclear power plant operation cycle leads to improvement of its capacity factor and affects to suppress thermal plant generation of which fuel cost is relatively high. On the other hand, the number of nuclear fuel assembly to be exchanged at the time of maintenance increases with the operation cycle extension and this makes the fuel cost of nuclear generation high. For this reason, there exists the optimum operation cycle from the power system operation. This report deals with the optimum operation cycle of nuclear plant as the optimum sharing problem of generated energy between nuclear and thermal plants. The incremental fuel cost is considered to find the optimum value. The effects of the generation mix and high burn-up fuel on optimum operation cycle are examined. (author)

  17. INTEGRATED PYROLYSIS COMBINED CYCLE BIOMASS POWER SYSTEM CONCEPT DEFINITION

    Energy Technology Data Exchange (ETDEWEB)

    Eric Sandvig; Gary Walling; Robert C. Brown; Ryan Pletka; Desmond Radlein; Warren Johnson

    2003-03-01

    Advanced power systems based on integrated gasification/combined cycles (IGCC) are often presented as a solution to the present shortcomings of biomass as fuel. Although IGCC has been technically demonstrated at full scale, it has not been adopted for commercial power generation. Part of the reason for this situation is the continuing low price for coal. However, another significant barrier to IGCC is the high level of integration of this technology: the gas output from the gasifier must be perfectly matched to the energy demand of the gas turbine cycle. We are developing an alternative to IGCC for biomass power: the integrated (fast) pyrolysis/ combined cycle (IPCC). In this system solid biomass is converted into liquid rather than gaseous fuel. This liquid fuel, called bio-oil, is a mixture of oxygenated organic compounds and water that serves as fuel for a gas turbine topping cycle. Waste heat from the gas turbine provides thermal energy to the steam turbine bottoming cycle. Advantages of the biomass-fueled IPCC system include: combined cycle efficiency exceeding 37 percent efficiency for a system as small as 7.6 MW{sub e}; absence of high pressure thermal reactors; decoupling of fuel processing and power generation; and opportunities for recovering value-added products from the bio-oil. This report provides a technical overview of the system including pyrolyzer design, fuel clean-up strategies, pyrolysate condenser design, opportunities for recovering pyrolysis byproducts, gas turbine cycle design, and Rankine steam cycle. The report also reviews the potential biomass fuel supply in Iowa, provide and economic analysis, and present a summery of benefits from the proposed system.

  18. INTEGRATED PYROLYSIS COMBINED CYCLE BIOMASS POWER SYSTEM CONCEPT DEFINITION

    International Nuclear Information System (INIS)

    Advanced power systems based on integrated gasification/combined cycles (IGCC) are often presented as a solution to the present shortcomings of biomass as fuel. Although IGCC has been technically demonstrated at full scale, it has not been adopted for commercial power generation. Part of the reason for this situation is the continuing low price for coal. However, another significant barrier to IGCC is the high level of integration of this technology: the gas output from the gasifier must be perfectly matched to the energy demand of the gas turbine cycle. We are developing an alternative to IGCC for biomass power: the integrated (fast) pyrolysis/ combined cycle (IPCC). In this system solid biomass is converted into liquid rather than gaseous fuel. This liquid fuel, called bio-oil, is a mixture of oxygenated organic compounds and water that serves as fuel for a gas turbine topping cycle. Waste heat from the gas turbine provides thermal energy to the steam turbine bottoming cycle. Advantages of the biomass-fueled IPCC system include: combined cycle efficiency exceeding 37 percent efficiency for a system as small as 7.6 MWe; absence of high pressure thermal reactors; decoupling of fuel processing and power generation; and opportunities for recovering value-added products from the bio-oil. This report provides a technical overview of the system including pyrolyzer design, fuel clean-up strategies, pyrolysate condenser design, opportunities for recovering pyrolysis byproducts, gas turbine cycle design, and Rankine steam cycle. The report also reviews the potential biomass fuel supply in Iowa, provide and economic analysis, and present a summery of benefits from the proposed system

  19. Preliminary Modelling Results for an Otto Cycle/Stirling Cycle Hybrid-engine-based Power Generation System

    OpenAIRE

    Cullen, Barry, (Thesis); McGovern, Jim; Feidt, Michel; Petrescu, Stoian

    2009-01-01

    This paper presents preliminary data and results for a system mathematical model for a proposed Otto Cycle / Stirling Cycle hybrid-engine-based power generation system. The system is a combined cycle system with the Stirling cycle machine operating as a bottoming cycle on the Otto cycle exhaust. The application considered is that of a stationary power generation scenario wherein the Stirling cycle engine operates as a waste heat recovery device on the exhaust stream of the Otto cycle engine. ...

  20. Assessment of ceramic composites for MMW space nuclear power systems

    International Nuclear Information System (INIS)

    Proposed multimegawatt nuclear power systems which operate at high temperatures, high levels of stress, and in hostile environments, including corrosive working fluids, have created interest in the use of ceramic composites as structural materials. This report assesses the applicability of several ceramic composites in both Brayton and Rankine cycle power systems. This assessment considers an equilibrium thermodynamic analysis and also a nonequilibrium assessment. (FI)

  1. Preliminary design study of S-CO2 power conversion system for PG-SFR

    International Nuclear Information System (INIS)

    This paper discusses the preliminary S-CO2 cycle design for PG-SFR condition considering the size and efficiency. PG-SFR, which stands for Prototype Generation IV - Sodium-cooled Fast Reactor is currently under development mainly by KAERI. The original design adopted a conventional steam Rankine cycle for the power conversion system but violent Sodium Water Reaction (SWR) raises a concern on the system safety. To suggest an alternative option, previous studies explored the SFR application of various gas Brayton cycles to increase the safety and simplify the safety system. A previous study compared and evaluated the performance of S-CO2, helium and nitrogen Brayton cycles for the SFR power conversion systems. Among those Brayton cycles, S-CO2 cycle can achieve high efficiency even comparable with the steam Rankine cycle

  2. Preliminary design study of S-CO{sub 2} power conversion system for PG-SFR

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Yoonhan; Lee, Jekyoung; Kim, Seong Gu; Jung, Hwa Yong; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2013-10-15

    This paper discusses the preliminary S-CO{sub 2} cycle design for PG-SFR condition considering the size and efficiency. PG-SFR, which stands for Prototype Generation IV - Sodium-cooled Fast Reactor is currently under development mainly by KAERI. The original design adopted a conventional steam Rankine cycle for the power conversion system but violent Sodium Water Reaction (SWR) raises a concern on the system safety. To suggest an alternative option, previous studies explored the SFR application of various gas Brayton cycles to increase the safety and simplify the safety system. A previous study compared and evaluated the performance of S-CO{sub 2}, helium and nitrogen Brayton cycles for the SFR power conversion systems. Among those Brayton cycles, S-CO{sub 2} cycle can achieve high efficiency even comparable with the steam Rankine cycle.

  3. Improvement of supercritical CO2 Brayton cycle using binary gas mixture

    International Nuclear Information System (INIS)

    A Sodium-cooled Fast Reactor (SFR) is one of the strongest candidates for the next generation nuclear reactor. However, the conventional design of a SFR concept with an indirect Rankine cycle is inevitably subjected to a sodium-water reaction. To prevent hazardous situation caused by sodium-water reaction, the SFR with Brayton cycle using Supercritical Carbon dioxide (S-CO2 cycle) as a working fluid can be an alternative approach. The S-CO2 Brayton cycle is more sensitive to the critical point of working fluids than other Brayton cycles. This is because compressor work significantly decreases at slightly above the critical point due to high density near the boundary between the supercritical state and the subcritical state. For this reason, the minimum temperature and pressure of cycle are just above the CO2 critical point. The critical point acts as a limitation of the lowest operating condition of the cycle. In general, lowering the rejection temperature of a thermodynamic cycle increases the efficiency and thus, changing the critical point of CO2 can result in an improvement of the total cycle efficiency with the same cycle layout. Modifying the critical point of the working fluid can be done by adding other gases to CO2. The direction and range of the CO2 critical point variation depends on the mixed component and its amount. In particular, chemical reactivity of the gas mixture itself and the gas mixture with sodium at high temperatures are of interest. To modify the critical point of the working fluid, several gases were chosen as candidates by which chemical stability with sodium within the interested range of cycle operating condition was assured: CO2 was mixed with N2, O2, He, Ar and Xe. To evaluate the effect of shifting the critical point and changes in the properties of the S-CO2 Brayton cycle, a supercritical Brayton cycle analysis code connected with the REFPROP program from the NIST was developed. The developed code is for evaluating simple

  4. Development of the ANL plant dynamics code and control strategies for the supercritical carbon dioxide Brayton cycle and code validation with data from the Sandia small-scale supercritical carbon dioxide Brayton cycle test loop

    International Nuclear Information System (INIS)

    Significant progress has been made in the ongoing development of the Argonne National Laboratory (ANL) Plant Dynamics Code (PDC), the ongoing investigation and development of control strategies, and the analysis of system transient behavior for supercritical carbon dioxide (S-CO2) Brayton cycles. Several code modifications have been introduced during FY2011 to extend the range of applicability of the PDC and to improve its calculational stability and speed. A new and innovative approach was developed to couple the Plant Dynamics Code for S-CO2 cycle calculations with SAS4A/SASSYS-1 Liquid Metal Reactor Code System calculations for the transient system level behavior on the reactor side of a Sodium-Cooled Fast Reactor (SFR) or Lead-Cooled Fast Reactor (LFR). The new code system allows use of the full capabilities of both codes such that whole-plant transients can now be simulated without additional user interaction. Several other code modifications, including the introduction of compressor surge control, a new approach for determining the solution time step for efficient computational speed, an updated treatment of S-CO2 cycle flow mergers and splits, a modified enthalpy equation to improve the treatment of negative flow, and a revised solution of the reactor heat exchanger (RHX) equations coupling the S-CO2 cycle to the reactor, were introduced to the PDC in FY2011. All of these modifications have improved the code computational stability and computational speed, while not significantly affecting the results of transient calculations. The improved PDC was used to continue the investigation of S-CO2 cycle control and transient behavior. The coupled PDC-SAS4A/SASSYS-1 code capability was used to study the dynamic characteristics of a S-CO2 cycle coupled to a SFR plant. Cycle control was investigated in terms of the ability of the cycle to respond to a linear reduction in the electrical grid demand from 100% to 0% at a rate of 5%/minute. It was determined that

  5. Development of the ANL plant dynamics code and control strategies for the supercritical carbon dioxide Brayton cycle and code validation with data from the Sandia small-scale supercritical carbon dioxide Brayton cycle test loop.

    Energy Technology Data Exchange (ETDEWEB)

    Moisseytsev, A.; Sienicki, J. J. (Nuclear Engineering Division)

    2011-11-07

    Significant progress has been made in the ongoing development of the Argonne National Laboratory (ANL) Plant Dynamics Code (PDC), the ongoing investigation and development of control strategies, and the analysis of system transient behavior for supercritical carbon dioxide (S-CO{sub 2}) Brayton cycles. Several code modifications have been introduced during FY2011 to extend the range of applicability of the PDC and to improve its calculational stability and speed. A new and innovative approach was developed to couple the Plant Dynamics Code for S-CO{sub 2} cycle calculations with SAS4A/SASSYS-1 Liquid Metal Reactor Code System calculations for the transient system level behavior on the reactor side of a Sodium-Cooled Fast Reactor (SFR) or Lead-Cooled Fast Reactor (LFR). The new code system allows use of the full capabilities of both codes such that whole-plant transients can now be simulated without additional user interaction. Several other code modifications, including the introduction of compressor surge control, a new approach for determining the solution time step for efficient computational speed, an updated treatment of S-CO{sub 2} cycle flow mergers and splits, a modified enthalpy equation to improve the treatment of negative flow, and a revised solution of the reactor heat exchanger (RHX) equations coupling the S-CO{sub 2} cycle to the reactor, were introduced to the PDC in FY2011. All of these modifications have improved the code computational stability and computational speed, while not significantly affecting the results of transient calculations. The improved PDC was used to continue the investigation of S-CO{sub 2} cycle control and transient behavior. The coupled PDC-SAS4A/SASSYS-1 code capability was used to study the dynamic characteristics of a S-CO{sub 2} cycle coupled to a SFR plant. Cycle control was investigated in terms of the ability of the cycle to respond to a linear reduction in the electrical grid demand from 100% to 0% at a rate of 5

  6. Restrictions on linear heat capacities from Joule-Brayton maximum-work cycle efficiency.

    Science.gov (United States)

    Angulo-Brown, F; Gonzalez-Ayala, Julian; Arias-Hernandez, L A

    2014-02-01

    This paper discusses the possibility of using the Joule-Brayton cycle to determine the accessible value range for the coefficients a and b of the heat capacity at constant pressure C(p), expressed as C(p) = a + bT (with T the absolute temperature) by using the Carnot theorem. This is made for several gases which operate as the working fluids. Moreover, the landmark role of the Curzon-Ahlborn efficiency for this type of cycle is established. PMID:25353449

  7. Solar dynamic power system definition study

    Science.gov (United States)

    Wallin, Wayne E.; Friefeld, Jerry M.

    1988-01-01

    The solar dynamic power system design and analysis study compared Brayton, alkali-metal Rankine, and free-piston Stirling cycles with silicon planar and GaAs concentrator photovoltaic power systems for application to missions beyond the Phase 2 Space Station level of technology for all power systems. Conceptual designs for Brayton and Stirling power systems were developed for 35 kWe and 7 kWe power levels. All power systems were designed for 7-year end-of-life conditions in low Earth orbit. LiF was selected for thermal energy storage for the solar dynamic systems. Results indicate that the Stirling cycle systems have the highest performance (lowest weight and area) followed by the Brayton cycle, with photovoltaic systems considerably lower in performance. For example, based on the performance assumptions used, the planar silicon power system weight was 55 to 75 percent higher than for the Stirling system. A technology program was developed to address areas wherein significant performance improvements could be realized relative to the current state-of-the-art as represented by Space Station. In addition, a preliminary evaluation of hardenability potential found that solar dynamic systems can be hardened beyond the hardness inherent in the conceptual designs of this study.

  8. Preliminary Studies of Na2CO3 Elimination from Na/CO2 Reaction in S-CO2 Power Cycle coupled to SFR System

    International Nuclear Information System (INIS)

    In order to avoid the SWR, the supercritical CO2 (S-CO2) Brayton cycle was proposed as a design alternative to the steam Rankine cycle. The S-CO2 Brayton cycle has good features such as improved thermal efficiency, reduced total plant size by having compact turbomachinery and heat exchangers and relatively simplified cycle layout. However, several technical challenges are still remaining for application of S-CO2 Brayton cycle to SFR. This is because when the pressure boundary in sodium-CO2 heat exchanger (HX) fails then leaked CO2 reacts with sodium, although the SWR is eliminated. The reaction between sodium and CO2 is much milder than SWR but more complex. The reaction is affected by the reaction temperature and there is the possibility of sodium ignition at very high temperature. So far, some research works on Na/CO2 reaction has been done. The experiments for Na/CO2 surface reaction, wastage phenomenon and self-plugging of narrow flow channel of Na/CO2 HXs were successfully conducted in KAERI. CEA proposed the major Na/CO2 reaction formulas and performed the calorimetric studies. JAEA experimentally investigated reaction behavior of CO2 with a liquid sodium pool. However, any research works for treatment and removal of reaction products from Na/CO2 reaction has not been done so far. Generally, when the pressure boundary fails CO2 will be released to sodium side and the amount of leakage will be depending on the rupture size. CO2 will react with sodium in the sodium-CO2 HX. It will lead to an economical problem if the channel is plugged by the solid reaction products of Na/CO2 reaction. Since the whole system operation should be stopped or some sort of bypass system should be applied to replace the plugged channel, which will affect the system economics. Therefore, it needs a material which can clean up the solid reaction products of Na/CO2 reaction and contaminated system while minimizing the impact on economics. If there is a material that can act as a

  9. SP-100 reactor with Brayton conversion for lunar surface applications

    International Nuclear Information System (INIS)

    Examined here is the potential for integrating Brayton-cycle power conversion with the SP-100 reactor for lunar surface power system applications. Two designs were characterized and modeled. The first design integrates a 100-kWe SP-100 Brayton power system with a lunar lander. This system is intended to meet early lunar mission power needs while minimizing on-site installation requirements. Man-rated radiation protection is provided by an integral multilayer, cylindrical lithium hydride/tungsten (LiH/W) shield encircling the reactor vessel. Design emphasis is on ease of deployment, safety, and reliability, while utilizing relatively near-term technology. The second design combines Brayton conversion with the SP-100 reactor in a erectable 550-kWe powerplant concept intended to satisfy later-phase lunar base power requirements. This system capitalizes on experience gained from operating the initial 100-kWe module and incorporates some technology improvements. For this system, the reactor is emplaced in a lunar regolith excavation to provide man-rated shielding, and the Brayton engines and radiators are mounted on the lunar surface and extend radially from the central reactor. Design emphasis is on performance, safety, long life, and operational flexibility

  10. Intercooled Turbo-Brayton Power Converter for Spaceflight Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future NASA space missions require advanced systems to convert thermal energy into electric power. These systems must be reliable, efficient, and lightweight. In...

  11. Turbo-Brayton Power Converter for Spaceflight Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future NASA space missions require advanced systems to convert thermal energy into electric power. These systems must be reliable, efficient, and lightweight. In...

  12. Transient Accident Analysis of a Supercritical Carbon Dioxide Brayton Cycle Energy Converter Coupled to an Autonomous Lead-Cooled Fast Reactor

    International Nuclear Information System (INIS)

    The Supercritical Carbon Dioxide (S-CO2) Brayton Cycle is a promising advanced alternative to the Rankine saturated steam cycle and recuperated gas Brayton cycle for the energy converters of specific reactor concepts belonging to the U.S. Department of Energy Generation IV Nuclear Energy Systems Initiative. A new plant dynamics analysis computer code has been developed for simulation of the S-CO2 Brayton cycle coupled to an autonomous, natural circulation Lead-Cooled Fast Reactor (LFR). The plant dynamics code was used to simulate the whole-plant response to accident conditions. The specific design features of the reactor concept influencing passive safety are discussed and accident scenarios are identified for analysis. Results of calculations of the whole-plant response to loss-of-heat sink, loss-of-load, and pipe break accidents are demonstrated. The passive safety performance of the reactor concept is confirmed by the results of the plant dynamics code calculations for the selected accident scenarios. (authors)

  13. Optimization of Brayton cycles for low-to-moderate grade thermal energy sources

    International Nuclear Information System (INIS)

    Future electricity generation will involve low or moderate temperature technologies. In such a scenario, optimisation of thermodynamic cycles will be a key task. This work presents a systematic analysis to find the operating regime where Brayton cycles reach the highest efficiency, using real substances and given heat source and sink temperatures. Several configurations using fluids close to its critical point at the compressor inlet are considered. Irreversibility sources are carefully analysed, as well as the type of working fluid. The analysis is performed by means of a theoretical approach to obtain some trends, which are afterwards validated with real gases. Results show that the efficiency and the specific work improve if the compressor inlet is close to the critical point. Furthermore, these cycles are less sensitive to pressure drops and politropic efficiencies than those working with ideal gases. The above features are more evident when the ratio of heat source and heat sink temperatures is low. The selection of the gas becomes a fundamental issue in this quest. Critical temperature should be close to ambient temperature, low critical pressure is advisable and the R/cp factor measured at the ideal gas condition should be low to further enhance the efficiency. - Highlights: • Performance analysis of Brayton cycles with the compressor inlet close to the critical point. • Cycles are not very sensitive to pressure drops and isentropic efficiencies of the compressor. • Gas selection becomes important, regarding the critical pressure and temperature as well as the kind of fluid. • R/cp factor measured at the ideal gas condition should be as low as possible

  14. Advanced space power systems

    International Nuclear Information System (INIS)

    A review of electrical power source concepts for application to near term space missions is presented along with a comparison of their weight and area estimates. The power sources reviewed include photovoltaic solar arrays, solar concentrators, radioisotopic thermoelectric generators (RTG), Dynamic Isotope Power Subsystems (DIPS) and nuclear reactors. The solar arrays are found to be the lightest systems in the 1-6 kWe range for a 10 year mission life but they have the largest area of the practicable sources. Solar dynamics has the smallest area of the solar systems and has the lightest mass above 20 kWe of all the solar sources when a closed Brayton cycle power conversion system is used. The DIPS is the lightest weight system from 6 to 11 kWe above which the thermionic reactor is the lightest assuming a 38 foot boom is used to minimize shield weight

  15. A hybrid Brayton engine concept

    Science.gov (United States)

    Six, L. D.; Elkins, R.

    1980-01-01

    A first generation open cycle Brayton engine concept for use in full scale solar module testing was defined. The concept extended to include solar/fossil hybrid capability. The combustion system defined for hybrid operation consists of a wide range combustor liner, a single airblast atomizer, an ignitor and a high-voltage ignition unit. Wide range combustor operation would be achieved through combining pilot and primary zones. The hybrid control mode and the solar only control mode are both based on the concept of maintaining constant turbine inlet temperature and varying the engine speed for part-power operation. In addition, the hybrid control concept will allow the operator to set a minimum thermal power input to the engine by setting a corresponding minimum engine speed. When the solar thermal power input falls below this minimum, fossil fuel would be utilized to augment the solar thermal power input.

  16. Life Cycle Assessment and Life Cycle Costing of a SOFC system for distributed power generation

    International Nuclear Information System (INIS)

    Highlights: • Assessment of 230 kW SOFC system from a life cycle perspective. • LCA–LCC toolbox developed to compare SOFC and MGT. • Eight sustainability indicators are identified as drivers for decision making. • Investment cost is a bottle-neck for SOFC systems. • SOFC systems show environmental–economic benefits for household applications. - Abstract: Through the combination of Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) in a dedicated toolbox, the aim of this paper is to evaluate both potential environmental impacts and potential costs of the operation of a 230 kW Solid Oxide Fuel Cell (SOFC) system. LCA and LCC methodologies have been here applied for a comparison with a conventional technology, i.e. Micro Gas Turbine (MGT) for distributed power generation applications. A contribution analysis for the SOFC system fuelled with natural gas, reveals that the fuel supply is responsible of a relevant share of the environmental impact. The same system, fed with biogas, shows environmental benefits on global and regional impact categories, depending on the power energy mix used during the digestion process. For both SOFC and MGT systems, the life cycle hotspots are identifiable in the operation stage for the global warming category, and in the fuel supply stage for all the remaining impact categories. The LCA–LCC comparison between SOFC and MGT systems, based on a toolbox embedding a set of 8 sustainability indicators for decision making, shows that the SOFC system presents environmental and economic benefits in a life cycle perspective, particularly for household application. However, cost results to be the most sensitive bottle-neck for benchmarking with traditional energy systems. Therefore, the SOFC system is preferable to the conventional MGT technology when the sustainability of investment cost is demonstrated, whilst a wide advantage in environmental performance along the life cycle has been proved

  17. Life-cycle air emissions from PV power systems

    International Nuclear Information System (INIS)

    This paper addresses the air emission of grid supply versus grid-connected and off-grid photovoltaic power generation, using the framework of life-cycle assessment, in the contents of rural household energy supply in Australia. Emissions of carbon dioxide, sulphur dioxde and nitrous oxides are calculated for the three life-cycle stages of manufacture, use and disposal. Sensitivities to materials and data inputs, as well as to component efficiencies, lifetimes and sizing are discussed. For each supply option, demand management options, including insulation and appliance choice, and the substitution of solar heating or bottled gas for electricity are considered. The best option in all cases, in terms of life-cycle air emissions, is a grid-connected photovoltaic system used to supply an energy-efficient household with a mix of solar, gas and electric appliances. However, in financial terms, with current Australian energy prices, this option represents a high capital and life-cycle costs. Additionally, for the grid options, electricity costs do not significantly disadvantage the high demand scenarios. Both results provide a clear illustration of current Australian energy-pricing policies being in conflict with long-term environmental sustainability. (Author)

  18. Finite time exergy analysis and multi-objective ecological optimization of a regenerative Brayton cycle considering the impact of flow rate variations

    International Nuclear Information System (INIS)

    Highlights: • Defining a dimensionless parameter includes the finite-time and size concepts. • Inserting the concept of exergy of fluid streams into finite-time thermodynamics. • Defining, drawing and modifying of maximum ecological function curve. • Suggesting the appropriate performance zone, according to maximum ecological curve. - Abstract: In this study, the optimal performance of a regenerative Brayton cycle is sought through power and then ecological function maximization using finite-time thermodynamic concept and finite-size components. Multi-objective optimization is used for maximizing the ecological function. Optimizations are performed using genetic algorithm. In order to take into account the finite-time and finite-size concepts in current problem, a dimensionless mass-flow parameter is introduced deploying time variations. The variations of output power, total exergy destruction of the system, and decision variables for the optimum state (maximum ecological function state) are compared to the maximum power state using the dimensionless parameter. The modified ecological function in optimum state is obtained and plotted relating to the dimensionless mass-flow parameter. One can see that the modified ecological function study results in a better performance than that obtained with the maximum power state. Finally, the appropriate performance zone of the heat engine will be obtained

  19. Power Plant Cycling Costs

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N.; Besuner, P.; Lefton, S.; Agan, D.; Hilleman, D.

    2012-07-01

    This report provides a detailed review of the most up to date data available on power plant cycling costs. The primary objective of this report is to increase awareness of power plant cycling cost, the use of these costs in renewable integration studies and to stimulate debate between policymakers, system dispatchers, plant personnel and power utilities.

  20. Energy conversion system optimization study for multimegawatt space nuclear power applications

    International Nuclear Information System (INIS)

    The major objective of this paper is to present a detailed description of the energy conversion system analysis and optimization procedures that were part of a broader preliminary study aimed at designing a multimegawatt (MMW) space nuclear power system. In optimizing the energy conversion system it is assumed that the most massive component of the system is the radiator and therefore the subject of optimization is the radiator mass. The closed loop Brayton and the liquid metal Rankine cycles are analyzed for a 165 MWe system. The radiator mass optimized systems based on both cycles are compared for a wide range of operating conditions. In addition, for a 165 MWe power output, the MMW power system mass is calculated using an open loop Brayton cycle. For the desired electric output, results show that the hydrogen cooled/potassium Rankine cycle is the recommended energy conversion system since it is superior to any closed loop Brayton cycle. Additionally, results show that the open loop Brayton cycle system with hydrogen working fluid has mass comparable to the selected Rankine cycle system

  1. Analysis of required supporting systems for the Supercritical CO2 power conversion system

    OpenAIRE

    Freas, Rosemarv M.

    2007-01-01

    Recently, attention has been drawn to the viability of using S-CO(2) as a working fluid in modern reactor designs. Near the critical point, CO2 has a rapid rise in density allowing a significant reduction in the compressor work of a closed Brayton Cycle. Therefore, 45% efficiency can be achieved at much more moderate temperatures than is optimal for the helium Brayton cycles. An additional benefit of the S-CO2 system is its universal applicability as an indirect secondary Power Conversion Sys...

  2. Life cycle assessment of a biomass gasification combined-cycle power system

    Energy Technology Data Exchange (ETDEWEB)

    Mann, M.K.; Spath, P.L.

    1997-12-01

    The potential environmental benefits from biomass power are numerous. However, biomass power may also have some negative effects on the environment. Although the environmental benefits and drawbacks of biomass power have been debated for some time, the total significance has not been assessed. This study serves to answer some of the questions most often raised in regard to biomass power: What are the net CO{sub 2} emissions? What is the energy balance of the integrated system? Which substances are emitted at the highest rates? What parts of the system are responsible for these emissions? To provide answers to these questions, a life cycle assessment (LCA) of a hypothetical biomass power plant located in the Midwest United States was performed. LCA is an analytical tool for quantifying the emissions, resource consumption, and energy use, collectively known as environmental stressors, that are associated with converting a raw material to a final product. Performed in conjunction with a technoeconomic feasibility study, the total economic and environmental benefits and drawbacks of a process can be quantified. This study complements a technoeconomic analysis of the same process, reported in Craig and Mann (1996) and updated here. The process studied is based on the concept of power Generation in a biomass integrated gasification combined cycle (BIGCC) plant. Broadly speaking, the overall system consists of biomass production, its transportation to the power plant, electricity generation, and any upstream processes required for system operation. The biomass is assumed to be supplied to the plant as wood chips from a biomass plantation, which would produce energy crops in a manner similar to the way food and fiber crops are produced today. Transportation of the biomass and other materials is by both rail and truck. The IGCC plant is sized at 113 MW, and integrates an indirectly-heated gasifier with an industrial gas turbine and steam cycle. 63 refs., 34 figs., 32 tabs.

  3. Multi-Megawatt Power System Trade Study

    Energy Technology Data Exchange (ETDEWEB)

    Longhurst, Glen Reed; Schnitzler, Bruce Gordon; Parks, Benjamin Travis

    2002-02-01

    A concept study was undertaken to evaluate potential multi-megawatt power sources for nuclear electric propulsion. The nominal electric power requirement was set at 15 MWe with an assumed mission profile of 120 days at full power, 60 days in hot standby, and another 120 days of full power, repeated several times for 7 years of service. Two configurations examined were (1) a gas-cooled reactor based on the NERVA Derivative design, operating a closed cycle Brayton power conversion system; and (2) a molten metal-cooled reactor based on SP-100 technology, driving a boiling potassium Rankine power conversion system. This study considered the relative merits of these two systems, seeking to optimize the specific mass. Conclusions were that either concept appeared capable of approaching the specific mass goal of 3-5 kg/kWe estimated to be needed for this class of mission, though neither could be realized without substantial development in reactor fuels technology, thermal radiator mass efficiency, and power conversion and distribution electronics systems capable of operating at high temperatures. The gas-Brayton systems showed an apparent specific mass advantage (3.53 vs 6.43 kg/kWe for the baseline cases) under the set of assumptions used, but reconciling differences in conservatism in the design algorithms used would make results much more comparable. Brayton systems eliminate the need to deal with two-phase working fluid flows in the microgravity environment of space.

  4. Carbon-Carbon Composites as Recuperator Materials for Direct Gas Brayton Systems

    International Nuclear Information System (INIS)

    Of the numerous energy conversion options available for a space nuclear power plant (SNPP), one that shows promise in attaining reliable operation and high efficiency is the direct gas Brayton (GB) system. In order to increase efficiency, the GB system incorporates a recuperator that accounts for nearly half the weight of the energy conversion system (ECS). Therefore, development of a recuperator that is lighter and provides better performance than current heat exchangers could prove to be advantageous. The feasibility of a carbon-carbon (C/C) composite recuperator core has been assessed and a mass savings of 60% and volume penalty of 20% were projected. The excellent thermal properties, high-temperature capabilities, and low density of carbon-carbon materials make them attractive in the GB system, but development issues such as material compatibility with other structural materials in the system, such as refractory metals and superalloys, permeability, corrosion, joining, and fabrication must be addressed

  5. Carbon-Carbon Composites as Recuperator Material for Direct Gas Brayton Systems

    Energy Technology Data Exchange (ETDEWEB)

    RA Wolf

    2006-07-19

    Of the numerous energy conversion options available for a space nuclear power plant (SNPP), one that shows promise in attaining reliable operation and high efficiency is the direct gas Brayton (GB) system. In order to increase efficiency, the GB system incorporates a recuperator that accounts for nearly half the weight of the energy conversion system (ECS). Therefore, development of a recuperator that is lighter and provides better performance than current heat exchangers could prove to be advantageous. The feasibility of a carbon-carbon (C/C) composite recuperator core has been assessed and a mass savings of 60% and volume penalty of 20% were projected. The excellent thermal properties, high-temperature capabilities, and low density of carbon-carbon materials make them attractive in the GB system, but development issues such as material compatibility with other structural materials in the system, such as refractory metals and superalloys, permeability, corrosion, joining, and fabrication must be addressed.

  6. Conceptual Design of Electrical Propulsion System for Nuclear Operated Vessel Adventurer

    Energy Technology Data Exchange (ETDEWEB)

    Halimi, B.; Suh, K. Y. [Seoul National University, Seoul (Korea, Republic of)

    2009-05-15

    A design concept of the electric propulsion system for the Nuclear Operated Vessel Adventure (NOVA) is presented. NOVA employs Battery Omnibus Reactor Integral System (BORIS), a liquid metal cooled small fast integral reactor, and Modular Optimized Brayton Integral System (MOBIS), a supercritical CO {sub 2} (SCO{sub 2}) Brayton cycle as power converter to Naval Application Vessel Integral System (NAVIS)

  7. Status of the CNES-CEA joint program on space nuclear Brayton systems

    International Nuclear Information System (INIS)

    A cooperative program between the French Centre National d'Etudes Spatiales (CNES) and the Commissariat a l'Energie Atomique (CEA) was initiated in 1983, to investigate the possible development of 20 to 200 kWe space nuclear power systems to be launched by the next version of the European launcher, Ariane V. After completion in 1986 of preliminary conceptual studies of a reference 200 kWe turbo-electric power system, an additional 3 year study phase was decided, with the double objective of assessing the potential advantage of nuclear power systems versus solar photovoltaic or dynamic systems in the 20 kWe power range, and comparing various reactor candidate technologies and system options for 20 kWe space nuclear power systems, likely to meet the projected energy needs of future European space missions. A comprehensive program including conceptual design studies, operating transient analyses and technology base assessment, is currently applied to a few reference concepts of 20 kWe nuclear Brayton and thermoelectric systems, in order to establish sound technical and economical bases for selecting the design options and the development strategy of a first space nuclear power system in Europe

  8. Advanced space solar dynamic power systems beyond IOC Space Station

    Science.gov (United States)

    Wallin, Wayne E.; Dustin, Miles O.

    1987-01-01

    Three different solar dynamic power cycle systems were evaluated for application to missions projected beyond the IOC Space Station. All three systems were found to be superior to two photovoltaic systems (a planar silicon array and a GaAs concentrator array), with both lower weight and area. The alkali-metal Rankine cycle was eliminated from consideration due to low performance, and the Stirling cycle was found to be superior to the closed Brayton cycle in both weight and area. LiF salt, which establishes peak cycle temperatures for both of the considered cycles at about 1090 K, was shown to be the most suitable material for Thermal Energy Storage.

  9. Optimum heat power cycles for specified boundary conditions

    International Nuclear Information System (INIS)

    In this paper optimization of the power output of Carnot and closed Brayton cycles is considered for both finite and infinite thermal capacitance rates of the external fluid streams. The method of Lagrange multipliers is used to solve for working fluid temperatures that yield maximum power. Analytical expressions for the maximum power and the cycle efficiency at maximum power are obtained. A comparison of the maximum power from the two cycles for the same boundary conditions, i.e., the same heat source/sink inlet temperatures, thermal capacitance rates, and heat exchanger conductances, shows that the Brayton cycle can produce more power than the Carnot cycle. This comparison illustrates that cycles exist that can produce more power than the Carnot cycle. The optimum heat power cycle, which will provide the upper limit of power obtained from any thermodynamic cycle for specified boundary conditions and heat exchanger conductances is considered. The optimum heat power cycle is identified by optimizing the sum of the power output from a sequence of Carnot cycles. The shape of the optimum heat power cycle, the power output, and corresponding efficiency are presented. The efficiency at maximum power of all cycles investigated in this study is found to be equal to (or well approximated by) η = 1 - sq. root TL.in/φTH.in where φ is a factor relating the entropy changes during heat rejection and heat addition

  10. Off-design performance prediction of Radial Compressor of Supercritical CO{sub 2} Brayton Cycle for KAIST Micro Modular Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seongkuk; Lee, Jekyoung; Kim, Seong Gu; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-10-15

    KAIST research team suggested a new concept of SMR, which utilizes S-CO{sub 2} as the operating fluid and coolant. It was named as KAIST MMR(Micro Modular Reactor). Compared with existing SMR concepts, this reactor has advantages of achieving smaller volume of power conversion unit (PCU) containing the core and PCU in one vessel for the complete modularization passive air-cooling system more flexible installation in the inland area. In previous study, performance of turbomachinery in PCU was considered only on-design. But, off-design performances of each component can affect not only PCU but also the core because this reactor adopts the direct S-CO{sub 2} loop in GFR. Nuclear system is applied by relatively conservative criteria of safety. Thus, off-design performances of each component should be considered in order to be more realistic reactor. The suggested turbomachinery size of the S-CO{sub 2} cycle is relatively smaller than those of helium Brayton cycle and steam Rankine cycle. Performance analysis of compressor is conducted by KAIST-TMD in case of on-design and off-design. Compressor efficiency in on-design conditions is obtained 84.51 %. But compressor performance in off-design conditions decreases certainly. This means that more heat than existing prediction is rejected by air-cooling system. KAIST-TMD will be verified with more experiment data for providing the results of more accurate analysis. Also, this code will be modified to couple with safety analysis codes and S-CO{sub 2} cycle analysis codes in the future. Furthermore, authors will consider aerodynamic performance analysis and various losses for more realization.

  11. Models for multimegawatt space power systems

    Energy Technology Data Exchange (ETDEWEB)

    Edenburn, M.W.

    1990-06-01

    This report describes models for multimegawatt, space power systems which Sandia's Advanced Power Systems Division has constructed to help evaluate space power systems for SDI's Space Power Office. Five system models and models for associated components are presented for both open (power system waste products are exhausted into space) and closed (no waste products) systems: open, burst mode, hydrogen cooled nuclear reactor -- turboalternator system; open, hydrogen-oxygen combustion turboalternator system; closed, nuclear reactor powered Brayton cycle system; closed, liquid metal Rankine cycle system; and closed, in-core, reactor therminonic system. The models estimate performance and mass for the components in each of these systems. 17 refs., 8 figs., 15 tabs.

  12. Exergy performance analysis for irreversible closed Brayton cycle combined cooling, heating and power generation plant driven by residual energy and heat of blast furnace%高炉余能余热驱动的不可逆闭式布雷顿热电冷联产装置(炯)性能分析

    Institute of Scientific and Technical Information of China (English)

    冯辉君; 陈林根; 孙丰瑞

    2013-01-01

    A combined cooling,heating and power (CCHP) generation plant model composing by one irreversible closed Brayton cycle driven by residual energy and heat of blast furnace and one endoreversible four-heat-reservoir absorption refrigeration cycle was established by using finite time thermodynamics.The expressions of the exergy output rate and exergy efficiency were derived.The effects of the cycle parameters on the characteristics of exergy output rate and exergy efficiency versus pressure ratio were analyzed by using numerical calculations.The performances of the maximum exergy output rate was compared with that of the maximum exergy efficiency and some suggestions on the designs and operations of actual CCHP plants were proposed.%用有限时间热力学理论建立了由一个高炉余能余热驱动的不可逆闭式布雷顿循环和一个内可逆四热源吸收式制冷循环组成的热电冷联产循环模型,导出了其(娴)输出率和(炯)效率的表达式.利用数值计算方法,分析了循环各参数对(炯)输出率和(炯)效率与压比关系的影响,比较了最大(炯)输出率和最大(炯)效率性能,给出了实际热电冷联产装置设计和运行的建议.

  13. A Mass Computation Model for Lightweight Brayton Cycle Regenerator Heat Exchangers

    Science.gov (United States)

    Juhasz, Albert J.

    2010-01-01

    Based on a theoretical analysis of convective heat transfer across large internal surface areas, this paper discusses the design implications for generating lightweight gas-gas heat exchanger designs by packaging such areas into compact three-dimensional shapes. Allowances are made for hot and cold inlet and outlet headers for assembly of completed regenerator (or recuperator) heat exchanger units into closed cycle gas turbine flow ducting. Surface area and resulting volume and mass requirements are computed for a range of heat exchanger effectiveness values and internal heat transfer coefficients. Benefit cost curves show the effect of increasing heat exchanger effectiveness on Brayton cycle thermodynamic efficiency on the plus side, while also illustrating the cost in heat exchanger required surface area, volume, and mass requirements as effectiveness is increased. The equations derived for counterflow and crossflow configurations show that as effectiveness values approach unity, or 100 percent, the required surface area, and hence heat exchanger volume and mass tend toward infinity, since the implication is that heat is transferred at a zero temperature difference. To verify the dimensional accuracy of the regenerator mass computational procedure, calculation of a regenerator specific mass, that is, heat exchanger weight per unit working fluid mass flow, is performed in both English and SI units. Identical numerical values for the specific mass parameter, whether expressed in lb/(lb/sec) or kg/ (kg/sec), show the dimensional consistency of overall results.

  14. Analysis of thermal cycles and working fluids for power generation in space

    International Nuclear Information System (INIS)

    Production of power in space for terrestrial use is of great interest in view of the rapidly rising power demand and its environmental impacts. Space also offers a very low temperature, making it a perfect heat sink for power plants, thus offering much higher efficiencies. This paper focuses on the evaluation and analysis of thermal Brayton, Ericsson and Rankine power cycles operating at space conditions on several appropriate working fluids. Under the examined conditions, the thermal efficiency of Brayton cycles reaches 63%, Ericsson 74%, and Rankine 85%. These efficiencies are significantly higher than those for the computed or real terrestrial cycles: by up to 45% for the Brayton, and 17% for the Ericsson; remarkably 44% for the Rankine cycle even when compared with the best terrestrial combined cycles. From the considered working fluids, the diatomic gases (N2 and H2) produce somewhat better efficiencies than the monatomic ones in the Brayton and Rankine cycles. The Rankine cycles require radiator areas that are larger by up to two orders of magnitude than those required for the Brayton and Ericsson cycles. The results of the analysis of the sensitivity of the cycle performance parameters to major parameters such as turbine inlet temperature and pressure ratio are presented, equations or examining the effects of fluid properties on the radiator area and pressure drop were developed, and the effects of the working fluid properties on cycle efficiency and on the power production per unit radiator area were explored to allow decisions on the optimal choice of working fluids

  15. Thermodynamic cycles optimised for medium enthalpy units of concentrating solar power

    International Nuclear Information System (INIS)

    Concentrated solar power presents the drawback of decreasing radiation capture efficiency as the temperature of the receiver increases, because thermal losses increase as well. Low temperature at the receiver is an advantage for radiation concentrators, as they present high capture efficiency, but this fact changes into a drawback because of the low efficiency of the thermodynamic cycles working with a low temperature heat source. An analysis is presented on the performance of real fluids working with such a type of heat sources that can be generated in simple solar thermal units. Both Joule–Brayton cycles and dry-turbine Rankine cycles are considered, using regenerative heat exchangers for heat recovering. The driving force of this research is to look for working fluids with actual thermodynamic characteristics which fit well with temperatures of the heat source and sink. Some unconventional substances, as refrigerant R-125 or SF6, show good performance. They may be suitable at certain regimes of Rankine and Brayton cycles and could work in fast-reacting systems. Of course, differences in the performance of Brayton and Rankine cycles convey differences in the complexity and cost of the components, but they offer a wide field for coherently choosing the working fluid and thermal conditions. - Highlights: • Analysis of Brayton and Rankine cycles close to the critical point. • Performance of transcritical and supercritical cycles. • The close to critical point region is a promising region for low-to-moderate temperature applications. • Fluid selection becomes important. SF6 and R-125 present good performance

  16. Supercritical Carbon Dioxide Brayton Cycle for SFR Applications: Optimization, Transient Analysis, and Control

    International Nuclear Information System (INIS)

    A Plant Dynamics Code (PDC) has been under development at Argonne National Laboratory for several years to investigate steady-state and transient performance and behavior of the S-CO2 cycle as an alternative power converter for advanced SFRs. The code was specifically developed to address unique features of the S-CO2 cycle, including operation near the critical point and the effect of properties variation on the design and transient behavior of turbomachinery and heat exchangers. A coupling approach between PDC and SAS4A/SASSYS-1 Liquid Metal Reactor Code System has been implemented to allow simultaneous investigation of transient behavior of liquid metal-cooled reactors and S-CO2 cycle balance-of-plants. PDC has been used to optimize the S-CO2 cycle design and to develop a control strategy. It has been demonstrated that with the proposed control systems the cycle can be effectively and stably operated over the entire range of grid loads and for decay heat removal. (author)

  17. Exergy Analysis of Combined Cycle Power Plant: NTPC Dadri, India

    OpenAIRE

    Tiwari, Arvind Kumar; M. M. Hasan; Islam, Mohd.

    2013-01-01

    The aim of the present paper is to exergy analysis of combined Brayton/Rankine power cycle of NTPC Dadri India. Theoretical exergy analysis is carried out for different components of dadri combined cycle power plant which consists of a gas turbine unit, heat recovery steam generator without extra fuel consumption and steam turbine unit. The results pinpoint that more exergy losses occurred in the gas turbine combustion chamber. Its reached 35% of the total exergy losses while the exergy losse...

  18. Exergy Analysis of Combined Cycle Power Plant: NTPC Dadri, India

    OpenAIRE

    Arvind Kumar Tiwari; M. M. Hasan; Mohd Islam,

    2012-01-01

    The aim of the present paper is to exergy analysis of combined Brayton/Rankine power cycle of NTPC Dadri India. Theoretical exergy analysis is carried out for different components of dadri combined cycle power plant which consists of a gas turbine unit, heat recovery steam generator without extra fuel consumption and steam turbine unit. The results pinpoint that more exergy losses occurred in the gas turbine combustion chamber. Its reached 35% of the total exergy losses while the exergy losse...

  19. A brief review study of various thermodynamic cycles for high temperature power generation systems

    International Nuclear Information System (INIS)

    Highlights: • Various high temperature power generation cycles for are reviewed and analyzed. • The operating temperature is higher than 700 K for high temperature power systems. • Thermodynamic cycle model study and working fluid choices are discussed. • Characteristics and future developments of high temperature cycles are presented and compared. - Abstract: This paper presents a review of the previous studies and papers about various thermodynamic cycles working for high temperature power generation procedures, in these cycles the highest temperature is not lower than 700 K. Thermodynamic cycles that working for power generation are divided into two broad categories, thermodynamic cycle model study and working fluid analysis. Thermodynamic cycle contains the simple cycle model and the complex cycle model, emphasis has been given on the complex thermodynamic cycles due to their high thermal efficiencies. Working fluids used for high temperature thermodynamic cycles is a dense gas rather than a liquid. A suitable thermodynamic cycle is crucial for effectively power generation especially under the condition of high temperature. The main purpose is to find out the characteristics of various thermodynamic cycles when they are working in the high temperature region for power generation. As this study shows, combined cycles with both renewable and nonrenewable energies as the heat source can show good performance

  20. 78 FR 47012 - Developing Software Life Cycle Processes Used in Safety Systems of Nuclear Power Plants

    Science.gov (United States)

    2013-08-02

    ... CFR Part 50 as they apply to software development processes. The criteria of Appendices A and B apply... COMMISSION Developing Software Life Cycle Processes Used in Safety Systems of Nuclear Power Plants AGENCY... Software Life Cycle Processes for Digital Computer Software used in Safety Systems of Nuclear Power...

  1. Development of 0.5-5 W, 10K Reverse Brayton Cycle Cryocoolers - Phase II Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Doty, F. D.; Boman, A.; Arnold, S.; Spitzmesser, J. B.; Jones, D.; McCree, D.; Hacker, L. J.

    2001-10-15

    Miniature cryocoolers for the 8-30 K range are needed to provide 0.5-5 w of cooling to high sensitivity detectors (for long-wave-length IR, magnetism, mm-wave, X-ray, dark matter, and possibly y-ray detection) while maintaining low mass, ultra-low vibration, and good efficiency. This project presents a new approach to eliminating the problems normally encountered in efforts to build low-vibration, fieldable, miniature cryocoolers. Using the reverse Brayton Cycle (RBC), the approach applies and expands on existing spinner technology previously used only in Nuclear Magnetic Resonance (NMR) probes.

  2. The efficiency of an open-cavity tubular solar receiver for a small-scale solar thermal Brayton cycle

    International Nuclear Information System (INIS)

    Highlights: • Results show efficiencies of a low-cost stainless steel tubular cavity receiver. • Optimum ratio of 0.0035 is found for receiver aperture area to concentrator area. • Smaller receiver tube and higher mass flow rate increase receiver efficiency. • Larger tube and smaller mass flow rate increase second law efficiency. • Large-tube receiver performs better in the small-scale solar thermal Brayton cycle. - Abstract: The first law and second law efficiencies are determined for a stainless steel closed-tube open rectangular cavity solar receiver. It is to be used in a small-scale solar thermal Brayton cycle using a micro-turbine with low compressor pressure ratios. There are many different variables at play to model the air temperature increase of the air running through such a receiver. These variables include concentrator shape, concentrator diameter, concentrator rim angle, concentrator reflectivity, concentrator optical error, solar tracking error, receiver aperture area, receiver material, effect of wind, receiver tube diameter, inlet temperature and mass flow rate through the receiver. All these variables are considered in this paper. The Brayton cycle requires very high receiver surface temperatures in order to be successful. These high temperatures, however, have many disadvantages in terms of heat loss from the receiver, especially radiation heat loss. With the help of ray-tracing software, SolTrace, and receiver modelling techniques, an optimum receiver-to-concentrator-area ratio of A′ ≈ 0.0035 was found for a concentrator with 45° rim angle, 10 mrad optical error and 1° tracking error. A method to determine the temperature profile and net heat transfer rate along the length of the receiver tube is presented. Receiver efficiencies are shown in terms of mass flow rate, receiver tube diameter, pressure drop, maximum receiver surface temperature and inlet temperature of the working fluid. For a 4.8 m diameter parabolic dish, the

  3. Performance characteristics of an irreversible regenerative magnetic Brayton refrigeration cycle using Gd0.74Tb0.26 as the working substance

    Science.gov (United States)

    Diguet, Gildas; Lin, Guoxing; Chen, Jincan

    2012-10-01

    The cycle model of an irreversible regenerative magnetic Brayton refrigerator using Gd0.74Tb0.26 as the working substance is established. Based on the experimental characteristics of iso-field heat capacities of the material Gd0.74Tb0.26 at 0 T and 2 T, the corresponding iso-field entropies are calculated and the thermodynamic performance of an irreversible regenerative magnetic Brayton refrigeration cycle is investigated. The effects of the irreversibilities in the two adiabatic processes and non-perfect regenerative process of the magnetic Brayton refrigeration cycle on the cooling quantity, the heat quantity released to the hot reservoir, the net cooling quantity and the coefficient of performance are discussed in detail. Some significant results are obtained.

  4. Life-cycle analysis results of geothermal systems in comparison to other power systems.

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J. L.; Clark, C. E.; Han, J.; Wang, M.; Energy Systems

    2010-10-11

    A life-cycle energy and greenhouse gas emissions analysis has been conducted with Argonne National Laboratory's expanded Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model for geothermal power-generating technologies, including enhanced geothermal, hydrothermal flash, and hydrothermal binary technologies. As a basis of comparison, a similar analysis has been conducted for other power-generating systems, including coal, natural gas combined cycle, nuclear, hydroelectric, wind, photovoltaic, and biomass by expanding the GREET model to include power plant construction for these latter systems with literature data. In this way, the GREET model has been expanded to include plant construction, as well as the usual fuel production and consumption stages of power plant life cycles. For the plant construction phase, on a per-megawatt (MW) output basis, conventional power plants in general are found to require less steel and concrete than renewable power systems. With the exception of the concrete requirements for gravity dam hydroelectric, enhanced geothermal and hydrothermal binary used more of these materials per MW than other renewable power-generation systems. Energy and greenhouse gas (GHG) ratios for the infrastructure and other life-cycle stages have also been developed in this study per kilowatt-hour (kWh) of electricity output by taking into account both plant capacity and plant lifetime. Generally, energy burdens per energy output associated with plant infrastructure are higher for renewable systems than conventional ones. GHG emissions per kWh of electricity output for plant construction follow a similar trend. Although some of the renewable systems have GHG emissions during plant operation, they are much smaller than those emitted by fossil fuel thermoelectric systems. Binary geothermal systems have virtually insignificant GHG emissions compared to fossil systems. Taking into account plant construction and operation, the

  5. Multi Megawatt Power System Analysis Report

    Energy Technology Data Exchange (ETDEWEB)

    Longhurst, Glen Reed; Harvego, Edwin Allan; Schnitzler, Bruce Gordon; Seifert, Gary Dean; Sharpe, John Phillip; Verrill, Donald Alan; Watts, Kenneth Donald; Parks, Benjamin Travis

    2001-11-01

    Missions to the outer planets or to near-by planets requiring short times and/or increased payload carrying capability will benefit from nuclear power. A concept study was undertaken to evaluate options for a multi-megawatt power source for nuclear electric propulsion. The nominal electric power requirement was set at 15 MWe with an assumed mission profile of 120 days at full power, 60 days in hot standby, and another 120 days of full power, repeated several times for 7 years of service. Of the numerous options considered, two that appeared to have the greatest promise were a gas-cooled reactor based on the NERVA Derivative design, operating a closed cycle Brayton power conversion system; and a molten lithium-cooled reactor based on SP-100 technology, driving a boiling potassium Rankine power conversion system. This study examined the relative merits of these two systems, seeking to optimize the specific mass. Conclusions were that either concept appeared capable of approaching the specific mass goal of 3-5 kg/kWe estimated to be needed for this class of mission, though neither could be realized without substantial development in reactor fuels technology, thermal radiator mass efficiency, and power conversion and distribution electronics and systems capable of operating at high temperatures. Though the gas-Brayton systems showed an apparent advantage in specific mass, differences in the degree of conservatism inherent in the models used suggests expectations for the two approaches may be similar. Brayton systems eliminate the need to deal with two-phase flows in the microgravity environment of space.

  6. Comparison Between helium cycle and Supercritical CO2 Cycle for MMR and AMR

    International Nuclear Information System (INIS)

    Korea Atomic Energy Research Institute (KAERI) started the development of Mobile Multi-Purpose Reactor (MMR), which is a 10MWth gas-cooled reactor. MMR is aiming for maximizing mobility, high performance, durability and safety. This is in order to use the MMR for many purposes such as ship propulsion, train engine and so on. MMR generally uses helium Brayton cycle as a power conversion system since it can obtain very simple system arrangement with direct cycle. However, some researchers have proposed that the supercritical carbon dioxide (S-CO2) Brayton cycle can be more efficient energy converting cycle for the high temperature gas cooled reactor (HTGR) and the very high temperature reactor (VHTR) system as well. Thus, this paper is to compare helium Brayton cycle to the S-CO2 Brayton cycle in terms of the efficiency while varying turbine inlet temperature (T. I. T). A cascaded S-CO2 cycle which had been proposed by Argonne National laboratory (ANL) was used as the S-CO2 Brayton cycle configuration. This cycle is to overcome the mismatch of temperature drop between reactor coolant and CO2 through the reactor heat exchanger (RHX). Our research team reviewed the ANL research by using the in-house codes developed by the Korea Advanced institute of Science and Technology (KAIST) research team. The calculation error between the in-house code and previous result was -0.36%

  7. Comparison Between helium cycle and Supercritical CO{sub 2} Cycle for MMR and AMR

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Seong Jun; Lee, Jeong Ik; Ahn, Yoon Han; Lee, Je Kyoung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2013-05-15

    Korea Atomic Energy Research Institute (KAERI) started the development of Mobile Multi-Purpose Reactor (MMR), which is a 10MWth gas-cooled reactor. MMR is aiming for maximizing mobility, high performance, durability and safety. This is in order to use the MMR for many purposes such as ship propulsion, train engine and so on. MMR generally uses helium Brayton cycle as a power conversion system since it can obtain very simple system arrangement with direct cycle. However, some researchers have proposed that the supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle can be more efficient energy converting cycle for the high temperature gas cooled reactor (HTGR) and the very high temperature reactor (VHTR) system as well. Thus, this paper is to compare helium Brayton cycle to the S-CO{sub 2} Brayton cycle in terms of the efficiency while varying turbine inlet temperature (T. I. T). A cascaded S-CO{sub 2} cycle which had been proposed by Argonne National laboratory (ANL) was used as the S-CO{sub 2} Brayton cycle configuration. This cycle is to overcome the mismatch of temperature drop between reactor coolant and CO{sub 2} through the reactor heat exchanger (RHX). Our research team reviewed the ANL research by using the in-house codes developed by the Korea Advanced institute of Science and Technology (KAIST) research team. The calculation error between the in-house code and previous result was -0.36%.

  8. Combined cycle power unit with a binary system based on waste geothermal brine at Mutnovsk geothermal power plant

    Science.gov (United States)

    Tomarov, G. V.; Shipkov, A. A.; Nikol'skii, A. I.; Semenov, V. N.

    2016-06-01

    The Russian geothermal power systems developed in the last few decades outperform their counterparts around the world in many respects. However, all Russian geothermal power stations employ steam as the geothermal fluid and discard the accompanying geothermal brine. In reality, the power of the existing Russian geothermal power stations may be increased without drilling more wells, if the waste brine is employed in combined cycle systems with steam and binary turbine units. For the example of the 50 MW Mutnovsk geothermal power plant, the optimal combined cycle power unit based on the waste geothermal brine is considered. It is of great interest to determine how the thermodynamic parameters of the secondary steam in the expansion unit and the pressure in the condenser affect the performance of the equipment in the combined cycle power unit at Mutnovsk geothermal power plant. For the utilization of the waste geothermal brine at Mutnovsk geothermal power plant, the optimal air temperature in the condensers of the combined cycle power unit is +5°C. The use of secondary steam obtained by flashing of the geothermal brine at Mutnovsk geothermal power plant 1 at a pressure of 0.2 MPa permits the generation of up to 8 MW of electric power in steam turbines and additional power of 5 MW in the turbines of the binary cycle.

  9. A prospective study of power cycles based on the expected sodium fast reactor parameters

    International Nuclear Information System (INIS)

    One of the main issues that has not been solved yet in the frame of Sodium Fast Reactors (SFR) is to choose the most appropriate power conversion system. This paper explores the performance of different power cycles, from traditional to innovative layouts trying to find the optimized solution. Based on the expected reactor parameters (i.e., inlet and outlet coolant temperatures, 395 deg.C and 545 deg.C, respectively), a subcritical Rankine similar to those of fossil power plant cycles has been proposed as a reference layout. Then, alternative layouts based on innovative Rankine and Brayton cycles have been investigated. Two Rankine supercritical layouts have been modeled and analyzed: one of them, adopted from the Supercritical Water Reactor of GIV (one reheater, nine pre-heaters and one moisture separator) and the other similar to some fossil plants (two reheaters, nine pre-heaters with no moisture separator). Simple Brayton cycle configurations based on Helium has been also studied. Several layouts have been modeled to study the effects of: inter-cooling between compression stages, absence of an intermediate loop and coupling of an organic Rankine cycle (ORC). (authors)

  10. Optimum performance analysis of a two-stage irreversible magnetization Brayton refrigeration system

    International Nuclear Information System (INIS)

    A two-stage magnetization Brayton refrigeration cycle model using a paramagnetic material as the working substance is established, in which the regeneration and the irreversibility in the adiabatic processes are taken into account. On the basis of the thermodynamic properties of a paramagnetic material, the expressions of some important parameters such as the coefficient of performance, refrigeration load and work input are derived and used to analyse the performance characteristics of the refrigeration cycle. The influence of the inter-magnetization process, irreversibility in the adiabatic processes and regeneration on the performance of the cycle is discussed in detail. The advantage of adding the inter-magnetization process is expounded and the magnetic field ratio related to the inter-magnetization process is optimized. Moreover, the optimal values of the temperatures of the working substance at different state points and the optimally operating region of the cycle are determined. The results obtained here are compared with those derived from some relevant magnetic Brayton refrigeration cycles, and consequently, some significant conclusions are obtained

  11. Life-cycle analysis results for geothermal systems in comparison to other power systems: Part II.

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J.L.; Clark, C.E.; Yuan, L.; Han, J.; Wang, M. (Energy Systems)

    2012-02-08

    A study has been conducted on the material demand and life-cycle energy and emissions performance of power-generating technologies in addition to those reported in Part I of this series. The additional technologies included concentrated solar power, integrated gasification combined cycle, and a fossil/renewable (termed hybrid) geothermal technology, more specifically, co-produced gas and electric power plants from geo-pressured gas and electric (GPGE) sites. For the latter, two cases were considered: gas and electricity export and electricity-only export. Also modeled were cement, steel and diesel fuel requirements for drilling geothermal wells as a function of well depth. The impact of the construction activities in the building of plants was also estimated. The results of this study are consistent with previously reported trends found in Part I of this series. Among all the technologies considered, fossil combustion-based power plants have the lowest material demand for their construction and composition. On the other hand, conventional fossil-based power technologies have the highest greenhouse gas (GHG) emissions, followed by the hybrid and then two of the renewable power systems, namely hydrothermal flash power and biomass-based combustion power. GHG emissions from U.S. geothermal flash plants were also discussed, estimates provided, and data needs identified. Of the GPGE scenarios modeled, the all-electric scenario had the highest GHG emissions. Similar trends were found for other combustion emissions.

  12. Investigation of alternative layouts for the supercritical carbon dioxide Brayton cycle for a sodium-cooled fast reactor

    International Nuclear Information System (INIS)

    Analyses of supercritical carbon dioxide (S-CO2) Brayton cycle performance have largely settled on the recompression supercritical cycle (or Feher cycle) incorporating a flow split between the main compressor downstream of heat rejection, a recompressing compressor providing direct compression without heat rejection, and high and low temperature recuperators to raise the effectiveness of recuperation and the cycle efficiency. Alternative cycle layouts have been previously examined by Angelino (Politecnico, Milan), by MIT (Dostal, Hejzlar, and Driscoll), and possibly others but not for sodium-cooled fast reactors (SFRs) operating at relatively low core outlet temperature. Thus, the present authors could not be sure that the recompression cycle is an optimal arrangement for application to the SFR. To ensure that an advantageous alternative layout has not been overlooked, several alternative cycle layouts have been investigated for a S-CO2 Brayton cycle coupled to the Advanced Burner Test Reactor (ABTR) SFR preconceptual design having a 510 deg. C core outlet temperature and a 470 deg. C turbine inlet temperature to determine if they provide any benefit in cycle performance (e.g., enhanced cycle efficiency). No such benefits were identified, consistent with the previous examinations, such that attention was devoted to optimizing the recompression supercritical cycle. The effects of optimizing the cycle minimum temperature and pressure are investigated including minimum temperatures and/or pressures below the critical values. It is found that improvements in the cycle efficiency of 1% or greater relative to previous analyses which arbitrarily fixed the minimum temperature and pressure can be realized through an optimal choice of the combination of the minimum cycle temperature and pressure (e.g., for a fixed minimum temperature there is an optimal minimum pressure). However, this leads to a requirement for a larger cooler for heat rejection which may impact the

  13. System studies of coal fired-closed cycle MHD for central station power plants

    Science.gov (United States)

    Zauderer, B.

    1976-01-01

    This paper presents a discussion of the closed cycle MHD results obtained in a recent study of various advanced energy conversion (ECAS) power systems. The study was part of the first phase of this ECAS study. Since this was the first opportunity to evaluate the coal fired closed cycle MHD system, a number of iterations were required to partially optimize the system. The present paper deals with the latter part of the study in which the direct coal fired, MHD topping-steam bottoming cycle was established as the current choice for central station power generation. The emphasis of the paper is on the background assumptions and the conclusions that can be drawn from the closed cycle MHD analysis. The author concludes that closed cycle MHD has efficiencies comparable to that of open cycle MHD and that both systems are considerably more efficient than the other system studies in Phase 1 of the GE ECAS. Its cost will possibly be slightly higher than that of the open cycle MHD system. Also, with reasonable fuel escalation assumptions, both systems can produce lower cost electricity than conventional steam power plants. Suggestions for further work in closed cycle MHD components and systems is made.

  14. Control system options and strategies for supercritical CO2 cycles.

    Energy Technology Data Exchange (ETDEWEB)

    Moisseytsev, A.; Kulesza, K. P.; Sienicki, J. J.; Nuclear Engineering Division; Oregon State Univ.

    2009-06-18

    The Supercritical Carbon Dioxide (S-CO{sub 2}) Brayton Cycle is a promising alternative to Rankine steam cycle and recuperated gas Brayton cycle energy converters for use with Sodium-Cooled Fast Reactors (SFRs), Lead-Cooled Fast Reactors (LFRs), as well as other advanced reactor concepts. The S-CO{sub 2} Brayton Cycle offers higher plant efficiencies than Rankine or recuperated gas Brayton cycles operating at the same liquid metal reactor core outlet temperatures as well as reduced costs or size of key components especially the turbomachinery. A new Plant Dynamics Computer Code has been developed at Argonne National Laboratory for simulation of a S-CO{sub 2} Brayton Cycle energy converter coupled to an autonomous load following liquid metal-cooled fast reactor. The Plant Dynamics code has been applied to investigate the effectiveness of a control strategy for the S-CO{sub 2} Brayton Cycle for the STAR-LM 181 MWe (400 MWt) Lead-Cooled Fast Reactor. The strategy, which involves a combination of control mechanisms, is found to be effective for controlling the S-CO{sub 2} Brayton Cycle over the complete operating range from 0 to 100 % load for a representative set of transient load changes. While the system dynamic analysis of control strategy performance for STARLM is carried out for a S-CO{sub 2} Brayton Cycle energy converter incorporating an axial flow turbine and compressors, investigations of the S-CO{sub 2} Brayton Cycle have identified benefits from the use of centrifugal compressors which offer a wider operating range, greater stability near the critical point, and potentially further cost reductions due to fewer stages than axial flow compressors. Models have been developed at Argonne for the conceptual design and performance analysis of centrifugal compressors for use in the SCO{sub 2} Brayton Cycle. Steady state calculations demonstrate the wider operating range of centrifugal compressors versus axial compressors installed in a S-CO{sub 2} Brayton Cycle as

  15. Power generation and heating performances of integrated system of ammonia–water Kalina–Rankine cycle

    International Nuclear Information System (INIS)

    Highlights: • Integrated system of ammonia–water Kalina–Rankine cycle (AWKRC) is investigated. • Ammonia–water Rankine cycle is operated for cogenerating room heating-water in winter. • Kalina cycle with higher efficiency is operated for power generation in other seasons. • Power recovery efficiency accounts thermal efficiency and waste heat absorbing ratio. • Heating water with 70 °C and capacity of 55% total reclaimed heat load is cogenerated. - Abstract: An integrated system of ammonia–water Kalina–Rankine cycle (AWKRC) for power generation and heating is introduced. The Kalina cycle has large temperature difference during evaporation and small one during condensation therefore with high thermal efficiency for power generation, while the ammonia–water Rankine cycle has large temperature difference during condensation as well as evaporation, thus it can be adopted to generate heating-water as a by-product in winter. The integrated system is based on the Kalina cycle and converted to the Rankine cycle with a set of valves. The performances of the AWKRC system in different seasons with corresponding cycle loops were studied and analyzed. When the temperatures of waste heat and cooling water are 300 °C and 25 °C respectively, the thermal efficiency and power recovery efficiency of Kalina cycle are 20.9% and 17.4% respectively in the non-heating seasons, while these efficiencies of the ammonia–water Rankine cycle are 17.1% and 13.1% respectively with additional 55.3% heating recovery ratio or with comprehensive efficiency 23.7% higher than that of the Kalina cycle in heating season

  16. Combined cycle solar central receiver hybrid power system study. Volume III. Appendices. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-11-01

    A design study for a 100 MW gas turbine/steam turbine combined cycle solar/fossil-fuel hybrid power plant is presented. This volume contains the appendices: (a) preconceptual design data; (b) market potential analysis methodology; (c) parametric analysis methodology; (d) EPGS systems description; (e) commercial-scale solar hybrid power system assessment; and (f) conceptual design data lists. (WHK)

  17. Modeling in TRNSYS of a single effect evaporation system powered by a Rankine cycle

    OpenAIRE

    Casimiro, Sergio; Ioakimidis, C.; Mendes, J. Farinha; Giestas, Margarida Canedo

    2012-01-01

    The paper presents an analysis of a Single Effect Evaporation (SEE) system as a pre-study to the feasibility of concentrated solar power plants (CSP) powering desalination units for cogeneration of water and electricity. An algorithm to model a SEE system in steady-state operation was made and is described in this work. This algorithm was implemented in TRNSYS environment, and a simple analysis was conducted of a SEE system powered by a Rankine cycle used in CSP plants.

  18. Space nuclear power systems

    International Nuclear Information System (INIS)

    Materials of the 19-th Symposium on Space Nuclear Energetic and Engine Units taking place in 2002, in Albuquerque, USA are reviewed. Reports on transformation of heat energy produced by nuclear reactors in electrical one are presented in the reports. Result of works on improvement as traditional (Brayton and Rankine cycles, thermoelectricity and thermionic emission), so innovation converter systems (Stirling engine, alkali metal thermal to electric converter - AMTEC, thermoacoustic engine) are represented

  19. A unified model of combined energy systems with different cycle modes and its optimum performance characteristics

    International Nuclear Information System (INIS)

    A unified model is presented for a class of combined energy systems, in which the systems mainly consist of a heat engine, a combustor and a counter-flow heat exchanger and the heat engine in the systems may have different thermodynamic cycle modes such as the Brayton cycle, Carnot cycle, Stirling cycle, Ericsson cycle, and so on. Not only the irreversibilities of the heat leak and finite-rate heat transfer but also the different cycle modes of the heat engine are considered in the model. On the basis of Newton's law, expressions for the overall efficiency and power output of the combined energy system with an irreversible Brayton cycle are derived. The maximum overall efficiency and power output and other relevant parameters are calculated. The general characteristic curves of the system are presented for some given parameters. Several interesting cases are discussed in detail. The results obtained here are very general and significant and can be used to discuss the optimal performance characteristics of a class of combined energy systems with different cycle modes. Moreover, it is significant to point out that not only the important conclusions obtained in Bejan's first combustor model and Peterson's general combustion driven model but also the optimal performance of a class of solar-driven heat engine systems can be directly derived from the present paper under some limit conditions

  20. Composite turbine blade design options for Claude (open) cycle OTEC power systems

    Energy Technology Data Exchange (ETDEWEB)

    Penney, T R

    1985-11-01

    Small-scale turbine rotors made from composites offer several technical advantages for a Claude (open) cycle ocean thermal energy conversion (OTEC) power system. Westinghouse Electric Corporation has designed a composite turbine rotor/disk using state-of-the-art analysis methods for large-scale (100-MW/sub e/) open cycle OTEC applications. Near-term demonstrations using conventional low-pressure turbine blade shapes with composite material would achieve feasibility and modern credibility of the open cycle OTEC power system. Application of composite blades for low-pressure turbo-machinery potentially improves the reliability of conventional metal blades affected by stress corrosion.

  1. Detailed analysis of the effect of the turbine and compressor isentropic efficiency on the thermal and exergy efficiency of a Brayton cycle

    Directory of Open Access Journals (Sweden)

    Živić Marija

    2014-01-01

    Full Text Available Energy and exergy analysis of a Brayton cycle with an ideal gas is given. The irreversibility of the adiabatic processes in turbine and compressor is taken into account through their isentropic efficiencies. The net work per cycle, the thermal efficiency and the two exergy efficiencies are expressed as functions of the four dimensionless variables: the isentropic efficiencies of turbine and compressor, the pressure ratio, and the temperature ratio. It is shown that the maximal values of the net work per cycle, the thermal and the exergy efficiency are achieved when the isentropic efficiencies and temperature ratio are as high as possible, while the different values of pressure ratio that maximize the net work per cycle, the thermal and the exergy efficiencies exist. These pressure ratios increase with the increase of the temperature ratio and the isentropic efficiency of compressor and turbine. The increase of the turbine isentropic efficiency has a greater impact on the increase of the net work per cycle and the thermal efficiency of a Brayton cycle than the same increase of compressor isentropic efficiency. Finally, two goal functions are proposed for thermodynamic optimization of a Brayton cycle for given values of the temperature ratio and the compressor and turbine isentropic efficiencies. The first maximizes the sum of the net work per cycle and thermal efficiency while the second the net work per cycle and exergy efficiency. In both cases the optimal pressure ratio is closer to the pressure ratio that maximizes the net work per cycle.

  2. MELCOR Extensions for Simulation of Modular Power Cycles and Thermochemical Cycles for the Generation of Hydrogen via Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Sal B Rodriguez; Randall O Gauntt; Randy Cole; Marcos Modesto; Katherine McFadden; Len Malczynski; Billy Martin [Sandia National Laboratories, P.O. Box 5800, MS 0748, Albuquerque, NM 87123 (United States); Shripad T Revankar; Karen Vierow [Purdue University, 355 North Lansing Street, West Lafayette, IN 46202 (United States); Dave Louie; Louis Archuleta [Omicron, Inc., 2500 Louisiana Blvd. NE, Suite 410, Albuquerque, NM 87110 (United States)

    2006-07-01

    Sandia National Laboratories (SNL) is currently extending MELCOR so that it can be used to simulate high-temperature nuclear reactors with modular secondary-side power components that are coupled to thermochemical cycles such as sulfur iodine (SI), the Westinghouse hybrid sulfur (HyS), and a generalized thermochemical cycle. To this extent, we will begin by extending MELCOR models for high-temperature gas cooled reactors, Brayton power cycles, an SI thermochemical cycle, and a graphical user interface (GUI). In addition, future versions of MELCOR will include a Monte Carlo module for uncertainty and optimization studies, modular components for major power cycles, a financial module, and a generalized thermochemical cycle. (authors)

  3. Nuclear power technology system with molten salt reactor for transuranium nuclides burning in closed fuel cycle

    International Nuclear Information System (INIS)

    A concept of nuclear power technology system with homogeneous molten salt reactors for burning and transmutation of long-lived radioactive toxic nuclides is considered in the paper. Disposition of such reactors in enterprises of fuel cycle allows to provide them with power and facilitate solution of problems with rad waste with minimal losses. (Authors)

  4. Development of a plant dynamics computer code for analysis of a supercritical carbon dioxide Brayton cycle energy converter coupled to a natural circulation lead-cooled fast reactor.

    Energy Technology Data Exchange (ETDEWEB)

    Moisseytsev, A.; Sienicki, J. J.

    2007-03-08

    STAR-LM is a lead-cooled pool-type fast reactor concept operating under natural circulation of the coolant. The reactor core power is 400 MWt. The open-lattice core consists of fuel pins attached to the core support plate, (the does not consist of removable fuel assemblies). The coolant flows outside of the fuel pins. The fuel is transuranic nitride, fabricated from reprocessed LWR spent fuel. The cladding material is HT-9 stainless steel; the steady-state peak cladding temperature is 650 C. The coolant is single-phase liquid lead under atmospheric pressure; the core inlet and outlet temperatures are 438 C and 578 C, respectively. (The Pb coolant freezing and boiling temperatures are 327 C and 1749 C, respectively). The coolant is contained inside of a reactor vessel. The vessel material is Type 316 stainless steel. The reactor is autonomous meaning that the reactor power is self-regulated based on inherent reactivity feedbacks and no external power control (through control rods) is utilized. The shutdown (scram) control rods are used for startup and shutdown and to stop the fission reaction in case of an emergency. The heat from the reactor is transferred to the S-CO{sub 2} Brayton cycle in in-reactor heat exchangers (IRHX) located inside the reactor vessel. The IRHXs are shell-and-tube type heat exchangers with lead flowing downwards on the shell side and CO{sub 2} flowing upwards on the tube side. No intermediate circuit is utilized. The guard vessel surrounds the reactor vessel to contain the coolant, in the very unlikely event of reactor vessel failure. The Reactor Vessel Auxiliary Cooling System (RVACS) implementing the natural circulation of air flowing upwards over the guard vessel is used to cool the reactor, in the case of loss of normal heat removal through the IRHXs. The RVACS is always in operation. The gap between the vessels is filled with liquid lead-bismuth eutectic (LBE) to enhance the heat removal by air by significantly reducing the thermal

  5. Small fission power systems for NEP

    International Nuclear Information System (INIS)

    Two nuclear electric propulsion (NEP) power system configurations are presented, each with an output power of 50 kWe and a system mass of about 2500 kg. Both consist of a reactor coupled to a recuperated Brayton power conversion system with a fixed conical radiator driven by loop heat pipes. In one system the reactor is gas-cooled with the gas directly driving the Brayton power conversion system. In the other the reactor is heatpipe-cooled with a heat exchanger between the reactor and the Brayton system. Two variations are described briefly with powers of 100 k We and 150 kWe. The mass scales approximately with the square root of the power

  6. Development of performance analysis system (NOPAS) for turbine cycle of nuclear power plant

    International Nuclear Information System (INIS)

    We have needs to develop a performance analysis system that can be used in domestic nuclear power plants to determine performance status of turbine cycle. We developed new NOPAS system to aid performance analysis of turbine cycle. Procedures of performance calculation are improved using several adaptations from standard calculation algorithms based on ASME (American Society of Mechanical Engineers) PTC (Performance Test Code). Robustness in the performance analysis is increased by verification and validation scheme for measured input data. The system also provides useful aids for performance analysis such as graphic heat balance of turbine cycle and components, turbine expansion lines, automatic generation of analysis reports. (author)

  7. A comparison of nuclear power systems for Brazil using plutonium and binary cycles

    International Nuclear Information System (INIS)

    Nuclear power systems based on plutonium cycle and binary cycle are compared taking into account natural uranium demand and reactor combination. The systems start with PWR type reactors (U5/U8) and change to systems composed exclusively of FBR type reactors or PWR-FBR symbiotic systems. Four loading modes are considered for the PWR and two for the FBR. The FBR is either a LMFBR loaded with PU/U or a LMFBR loaded the binary way. A linear and a non-linear capacity growth and two different criteria for the FBR introduction are considered. The results show that a 100 GWe permanent system can be established in 50 years in all cases, based on 300000 t of natural uranium and in case of delay in the FBR introduction and if a thermal-fast symbiotic system is chosen, a binary cycle could be more advantageous than a plutonium cycle. (F.E.)

  8. Energy, exergy analysis and working fluid selection of a Rankine cycle for subsea power system

    International Nuclear Information System (INIS)

    Highlights: • We propose a Rankine cycle based subsea power system for deep ocean power supply. • The turbine directly produces shaft power output. • Electrical heated boiler is utilized to conduct evaporation process. • 5 working fluids are selected and analyzed for the subsea Rankine cycle. • The turbine volumetric flow ratio (VRF) and size parameter (SP) are discussed. - Abstract: In this paper, a subcritical/transcritical Rankine cycle for subsea power system is investigated. By balancing the pressure between the inner and outer side of the rotary seal, the dynamic sealing problem for the subsea power system is minimized. This Rankine cycle is electrical heated and utilizes the surrounding deep seawater as the cooling source. The mathematical model was established based on the first and second law of thermodynamics and the simulation validation was made. Water–steam, CO2, C9H20, C10H22 and C12H26 are selected as the working fluid and the comparison was made. The results show that the subsea Rankine cycle can obtain a higher thermal efficiency as the working depth increases between 1000 and 5000 m. The thermal efficiencies are obtained as: 19.4–26.7% for water–steam cycle, 9.6–31.2% for CO2 cycle, 9.1–14.7% for C9H20 cycle, 8.0–13.5% for C10H22 cycle and 6.3–11.8% for C12H26 cycle, depending on the working depth. With the same working depth, the water–steam cycle has a higher thermal efficiency, exergy efficiency and turbine power output but requires higher total energy input; while the CO2 cycle can obtain a high thermal efficiency, exergy efficiency with lower energy consumption but produces less turbine power output. In addition, it is found exergy destruction mainly occur in the boiler and condenser, accounting for more than 90% in total

  9. Optimization of fog inlet air cooling system for combined cycle power plants using genetic algorithm

    International Nuclear Information System (INIS)

    In this research paper, a comprehensive thermodynamic modeling of a combined cycle power plant is first conducted and the effects of gas turbine inlet fogging system on the first and second law efficiencies and net power outputs of combined cycle power plants are investigated. The combined cycle power plant (CCPP) considered for this study consist of a double pressure heat recovery steam generator (HRSG) to utilize the energy of exhaust leaving the gas turbine and produce superheated steam to generate electricity in the Rankine cycle. In order to enhance understanding of this research and come up with optimum performance assessment of the plant, a complete optimization is using a genetic algorithm conducted. In order to achieve this goal, a new objective function is defined for the system optimization including social cost of air pollution for the power generation systems. The objective function is based on the first law efficiency, energy cost and the external social cost of air pollution for an operational system. It is concluded that using inlet air cooling system for the CCPP system and its optimization results in an increase in the average output power, first and second law efficiencies by 17.24%, 3.6% and 3.5%, respectively, for three warm months of year. - Highlights: • To model the combined cycle power plant equipped with fog inlet air cooling method. • To conduct both exergy and economic analyses for better understanding. • To conduct a complete optimization using a genetic algorithm to determine the optimal design parameters of the system

  10. Multimegawatt nuclear power systems for nuclear electric propulsion

    Science.gov (United States)

    George, Jeffrey A.

    1991-01-01

    Results from systems analysis studies of multimegawatt nuclear power systems are presented for application to nuclear electric propulsion. Specific mass estimates are presented for nearer term SP-100 reactor-based potassium Rankine and Brayton power systems for piloted and cargo missions. Growth SP-100/Rankine systems were found to range from roughly 7 to 10 kg/kWe specific mass depending on full power life requirements. The SP-100/Rankine systems were also found to result in a 4-kg/kWe savings in specific mass over SP-100/Brayton systems. The potential of advanced, higher temperature reactor and power conversion technologies for achieving reduced mass Rankine and Brayton systems was also investigated. A target goal of 5 kg/kWe specific mass was deemed reasonable given either 1400 K potassium Rankine with 1500 K lithium-cooled reactors or 2000 K gas cooled reactors with Brayton conversion.

  11. Gasification/combined-cycle power generation: environmental assessment of alternative systems

    Energy Technology Data Exchange (ETDEWEB)

    1978-11-01

    This report provides a basis for the comparative assessment of the potential performance capability, technological development, and economic and environmental impact associated with the operation of integrated low-Btu coal-gasification/combined-cycle power systems. Characterization of the integrated power system in terms of fuel processing, power production, and auxiliary systems is followed up with comparisons of alternative integrated-plant-design/fuel combinations with reference to the conventional coal-fired power plant, taking into account both economic and environmental factors. The report includes an assessment of the effects of recent regulatory changes on the prospects for integrated power systems and establishes a timetable for the probable commercial development of such systems by the utilities.

  12. A preliminary assessment of reactor candidate technologies for a 20 kWe space nuclear Brayton system

    International Nuclear Information System (INIS)

    In 1983, a cooperative program between the French Centre National d'Etudes Spaciales (CNES) and the Commissariat a l'Energie Atomique (CEA) was initiated to investigate the possible development of 20 to 200 kWe Brayton nuclear space systems. After the completion of the preliminary design of a reference 200 kWe turboelectric power system known as ERATO in 1986 (Carre et al. 1987), a second 3-year study phase was initiated. The objective of this phase was to assess the various reactor candidate technologies and system design options for 20 kWe power level for meeting the projected electric needs of the first European space missions (Carre et al. 1988). This paper presents the results of the design studies of three reference design concepts of 20 kWe turboelectric power systems covering a wide range of reactor temperatures and relevant material and reactor design technologies. Additionally the critical technology issues of the candidate systems, and other criteria relevant to the space missions are identified. The participation of the French industry in the present design activity is so far restricted to predesign studies of crucial components such as the turbomachinery and the reactor control actuators, and integration studies of the power system into the Ariane V launcher

  13. Heterogeneous gas core reactor and dual fluid closed cycle power conversion system. Final report, April 15, 1977--December 31, 1977

    International Nuclear Information System (INIS)

    The basic objective of this research program is the conceptual analysis and preliminary assessment of the Heterogeneous Gas Core Reactor (HGCR) concept and Dual-Fluid power conversion system. The research studies include preliminary HGCR neutronics design and optimization, preliminary analysis of fuel utilization characteristics as well as an assessment of the main safety features and non-proliferating characteristics of the HGCR. The dual-fluid power cycle analysis consists of a preliminary assessment of the basic dual-fluid power cycle to determine conditions for optimum cycle efficiency. Included are assessments of corresponding conventional power cycles for comparison with the dual-fluid power cycle

  14. A Score Function for Optimizing the Cycle-Life of Battery-Powered Embedded Systems

    DEFF Research Database (Denmark)

    Wognsen, Erik Ramsgaard; Haverkort, Boudewijn; Jongerden, Marijn;

    2015-01-01

    usage (charge and discharge) profiles on cycle life. The wear score function can not only be used to rank different usage profiles, these rankings can also be used as a criterion for optimizing the overall lifetime of a battery-powered system. We perform such an optimization on a nano-satellite case...

  15. An integrated solar thermal power system using intercooled gas turbine and Kalina cycle

    International Nuclear Information System (INIS)

    A new solar tower thermal power system integrating the intercooled gas turbine top cycle and the Kalina bottoming cycle is proposed in the present paper. The thermodynamic performance of the proposed system is investigated, and the irreversibility of energy conversion is disclosed using the energy–utilization diagram method. On the top cycle of the proposed system, the compressed air after being intercooled is heated at 1000 °C or higher at the solar tower receiver and is used to drive the gas turbine to generate power. The ammonia–water mixture as the working substance of the bottom cycle recovers the waste heat from the gas turbine to generate power. A concise analytical formula of solar-to-electric efficiency of the proposed system is developed. As a result, the peak solar-to-electric efficiency of the proposed system is 27.5% at a gas turbine inlet temperature of 1000 °C under the designed solar direct normal irradiance of 800 W/m2. Compared with a conventional solar power tower plant, the proposed integrated system conserves approximately 69% of consumed water. The results obtained in the current study provide an approach to improve solar-to-electric efficiency and offer a potential to conserve water for solar thermal power plants in arid area. -- Highlights: ► An Integrated Solar Thermal Power System is modeled. ► A formula forecasting the thermodynamic performance is proposed. ► The irreversibility of energy conversion is disclosed using an energy utilization method. ► The effect of key operational parameters on thermal performance is examined.

  16. Experimental Study of a Low-Temperature Power Generation System in an Organic Rankine Cycle

    DEFF Research Database (Denmark)

    Mu, Yongchao; Zhang, Yufeng; Deng, Na;

    2015-01-01

    the engine of the power generator. The style of the preheater was a shell and tube heat exchanger, which could provide a long path for the working fluid. A flooded heat exchanger with a high heat transfer coefficient was taken as the evaporator. R134a was used as working fluid for the Rankine cycle in...... the system. This study compared and analyzed the experimental performance of the prototype at different heat source temperatures. The results show that the preheater and flooded evaporator was used for sensible heating and latent heating of the working fluid, respectively, as expected. When the......This paper presents a new power generation system under the principle of organic Rankine cycle which can generate power with a low-temperature heat source. A prototype was built to investigate the proposed system. In the prototype, an air screw compressor was converted into an expander and used as...

  17. Combined cycle solar central receiver hybrid power system study. Final technical report. Volume II

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-11-01

    This study develops the conceptual design for a commercial-scale (nominal 100 MWe) central receiver solar/fossil fuel hybrid power system with combined cycle energy conversion. A near-term, metallic heat pipe receiver and an advanced ceramic tube receiver hybrid system are defined through parametric and market potential analyses. Comparative evaluations of the cost of power generation, the fuel displacement potential, and the technological readiness of these two systems indicate that the near-term hybrid system has better potential for commercialization by 1990. Based on the assessment of the conceptual design, major cost and performance improvements are projected for the near-term system. Constraints preventing wide-spread use were not identified. Energy storage is not required for this system and analyses show no economic advantages with energy storage provisions. It is concluded that the solar hybrid system is a cost effective alternative to conventional gas turbines and combined cycle generating plants, and has potential for intermediate-load market penetration at 15% annual fuel escalation rate. Due to their flexibility, simple solar/nonsolar interfacing, and short startup cycles, these hybrid plants have significant operating advantages. Utility company comments suggest that hybrid power systems will precede stand-alone solar plants.

  18. Energy Conversion Advanced Heat Transport Loop and Power Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Oh, C. H.

    2006-08-01

    operating conditions as well as trade offs between efficiency and capital cost. Prametric studies were carried out on reactor outlet temperature, mass flow, pressure, and turbine cooling. Recommendations on the optimal working fluid for each configuration were made. A steady state model comparison was made with a Closed Brayton Cycle (CBC) power conversion system developed at Sandia National Laboratory (SNL). A preliminary model of the CBC was developed in HYSYS for comparison. Temperature and pressure ratio curves for the Capstone turbine and compressor developed at SNL were implemented into the HYSYS model. A comparison between the HYSYS model and SNL loop demonstrated power output predicted by HYSYS was much larger than that in the experiment. This was due to a lack of a model for the electrical alternator which was used to measure the power from the SNL loop. Further comparisons of the HYSYS model and the CBC data are recommended. Engineering analyses were performed for several configurations of the intermediate heat transport loop that transfers heat from the nuclear reactor to the hydrogen production plant. The analyses evaluated parallel and concentric piping arrangements and two different working fluids, including helium and a liquid salt. The thermal-hydraulic analyses determined the size and insulation requirements for the hot and cold leg pipes in the different configurations. Economic analyses were performed to estimate the cost of the va

  19. Supercritical Water Reactor Cycle for Medium Power Applications

    Energy Technology Data Exchange (ETDEWEB)

    BD Middleton; J Buongiorno

    2007-04-25

    Scoping studies for a power conversion system based on a direct-cycle supercritical water reactor have been conducted. The electric power range of interest is 5-30 MWe with a design point of 20 MWe. The overall design objective is to develop a system that has minimized physical size and performs satisfactorily over a broad range of operating conditions. The design constraints are as follows: Net cycle thermal efficiency {ge}20%; Steam turbine outlet quality {ge}90%; and Pumping power {le}2500 kW (at nominal conditions). Three basic cycle configurations were analyzed. Listed in order of increased plant complexity, they are: (1) Simple supercritical Rankine cycle; (2) All-supercritical Brayton cycle; and (3) Supercritical Rankine cycle with feedwater preheating. The sensitivity of these three configurations to various parameters, such as reactor exit temperature, reactor pressure, condenser pressure, etc., was assessed. The Thermoflex software package was used for this task. The results are as follows: (a) The simple supercritical Rankine cycle offers the greatest hardware simplification, but its high reactor temperature rise and reactor outlet temperature may pose serious problems from the viewpoint of thermal stresses, stability and materials in the core. (b) The all-supercritical Brayton cycle is not a contender, due to its poor thermal efficiency. (c) The supercritical Rankine cycle with feedwater preheating affords acceptable thermal efficiency with lower reactor temperature rise and outlet temperature. (d) The use of a moisture separator improves the performance of the supercritical Rankine cycle with feedwater preheating and allows for a further reduction of the reactor outlet temperature, thus it was selected for the next step. Preliminary engineering design of the supercritical Rankine cycle with feedwater preheating and moisture separation was performed. All major components including the turbine, feedwater heater, feedwater pump, condenser, condenser pump

  20. Supercritical Water Reactor Cycle for Medium Power Applications

    International Nuclear Information System (INIS)

    Scoping studies for a power conversion system based on a direct-cycle supercritical water reactor have been conducted. The electric power range of interest is 5-30 MWe with a design point of 20 MWe. The overall design objective is to develop a system that has minimized physical size and performs satisfactorily over a broad range of operating conditions. The design constraints are as follows: Net cycle thermal efficiency (ge)20%; Steam turbine outlet quality (ge)90%; and Pumping power (le)2500 kW (at nominal conditions). Three basic cycle configurations were analyzed. Listed in order of increased plant complexity, they are: (1) Simple supercritical Rankine cycle; (2) All-supercritical Brayton cycle; and (3) Supercritical Rankine cycle with feedwater preheating. The sensitivity of these three configurations to various parameters, such as reactor exit temperature, reactor pressure, condenser pressure, etc., was assessed. The Thermoflex software package was used for this task. The results are as follows: (a) The simple supercritical Rankine cycle offers the greatest hardware simplification, but its high reactor temperature rise and reactor outlet temperature may pose serious problems from the viewpoint of thermal stresses, stability and materials in the core. (b) The all-supercritical Brayton cycle is not a contender, due to its poor thermal efficiency. (c) The supercritical Rankine cycle with feedwater preheating affords acceptable thermal efficiency with lower reactor temperature rise and outlet temperature. (d) The use of a moisture separator improves the performance of the supercritical Rankine cycle with feedwater preheating and allows for a further reduction of the reactor outlet temperature, thus it was selected for the next step. Preliminary engineering design of the supercritical Rankine cycle with feedwater preheating and moisture separation was performed. All major components including the turbine, feedwater heater, feedwater pump, condenser, condenser pump

  1. Low CO2-emissions hybrid solar combined-cycle power system with methane membrane reforming

    International Nuclear Information System (INIS)

    Based on the principle of cascade utilization of multiple energy resources, a gas-steam combined cycle power system integrated with solar thermo-chemical fuel conversion and CO2 capture has been proposed and analyzed. The collected solar heat at 550 °C drives the endothermic methane reforming and is converted to the produced syngas chemical exergy, and then released as high-temperature thermal energy via combustion for power generation, achieving its high-efficiency heat-power conversion. The reforming reaction is integrated with a hydrogen separation membrane, which continuously withdraws hydrogen from the reaction zone and enables nearly full methane conversion. The CO2 enriched gas being concentrated in the retentate zone is collected and processed with pre-combustion decarbonization. The system is thermodynamically simulated using the ASPEN PLUS code. The results show that with 91% CO2 captured, the specific CO2 emission is 25 g/kWh. An exergy efficiency of 58% and thermal efficiency of 51.6% can be obtained. A fossil fuel saving ratio of 31.2% is achievable with a solar thermal share of 28.2%, and the net solar-to-electricity efficiency based on the gross solar heat incident on the collector is about 36.4% compared with the same gas-steam combined cycle system with an equal CO2 removal ratio obtained by post-combustion decarbonization. - Highlights: ► A solar-assisted hybrid combined cycle power system has been proposed and analyzed. ► The system integrates power generation with solar-driven reforming and CO2 capture. ► solar heat upgrading and high-efficiency heat-to-power conversion are achieved. ► membrane reforming enables high CH4 conversion and pre-combustion CO2 capture. ► The system thermodynamic performances have been investigated and compared

  2. Performance comparison and parametric optimization of subcritical Organic Rankine Cycle (ORC) and transcritical power cycle system for low-temperature geothermal power generation

    International Nuclear Information System (INIS)

    Research highlights: → We conduct the thermodynamic and economic performance comparison of the fluids in both subcritical ORC and transcritical power cycle. → We perform parameter optimization based on five indicators. → The optimum operation parameters and working fluids are not the same for different indicators. → The LEC value is used as the determining factor for fluids screening. → The transcritical power cycle with R125 as the working fluid was a cost-effective approach. - Abstract: Organic Rankine Cycle (ORC) is a promising technology for converting the low-grade energy to electricity. This paper presents an investigation on the parameter optimization and performance comparison of the fluids in subcritical ORC and transcritical power cycle in low-temperature (i.e. 80-100 oC) binary geothermal power system. The optimization procedure was conducted with a simulation program written in Matlab using five indicators: thermal efficiency, exergy efficiency, recovery efficiency, heat exchanger area per unit power output (APR) and the levelized energy cost (LEC). With the given heat source and heat sink conditions, performances of the working fluids were evaluated and compared under their optimized internal operation parameters. The optimum cycle design and the corresponding operation parameters were provided simultaneously. The results indicate that the choice of working fluid varies the objective function and the value of the optimized operation parameters are not all the same for different indicators. R123 in subcritical ORC system yields the highest thermal efficiency and exergy efficiency of 11.1% and 54.1%, respectively. Although the thermal efficiency and exergy efficiency of R125 in transcritical cycle is 46.4% and 20% lower than that of R123 in subcritical ORC, it provides 20.7% larger recovery efficiency. And the LEC value is relatively low. Moreover, 22032L petroleum is saved and 74,019 kg CO2 is reduced per year when the LEC value is used as the

  3. Transient stability analysis of commercial scale open cycle disk MHD generator connected to power system

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, I. [Yatsushiro National Coll. of Technology, Dept. of Information and Electronics Engineering, Yatsushiro (Japan); Inui, Y. [Toyohashi Univ. of Technology, Dept. of Electrical and Electronic Engineering, Toyohashi (Japan); Hayanose, N. [Kobe City Coll. of Technology, Dept. of Electrical Engineering, Kobe (Japan); Ishikawa, M. [Tsukuba Univ., Inst. of Engineering Mechanics and Systems, Tsukuba (Japan)

    2003-03-01

    The authors propose and investigate a new improvement method for transient stability under power line fault condition for commercial scale open cycle subsonic inflow disk MHD generators connected to the power system through time dependent numerical simulations of a total interconnecting system. The method needs no additional device and only manipulates the inverter control angle. Its control sequence has two steps. At first, the control angle is reduced toward 90 deg just after the fault occurs. Next, it is linearly increased to its rated value with constant increasing rate per cycle after the removed line is reconnected. It is made clear through the simulations that the proposed control scheme of the inverter is very effective to improve the transient stability of the generator. The reduction of the inverter control angle is effective to stabilize the MHD generator, but the operating state shifts from its normal operation. The increase of the control angle can stably return the generator to its normal operation. (Author)

  4. THERMODYNAMIC ANALYSIS OF OPEN-CYCLE MULTISHAFT POWER SYSTEM WITH MULTIPLE REHEAT AND INTERCOOL

    Science.gov (United States)

    Glassman, A. J.

    1994-01-01

    This program computes the specific power output, specific fuel consumption, and cycle efficiency functions of turbine-inlet temperature, compressor pressure ratio, and component performance factors for power systems having any number of shafts up to a maximum of five. On each shaft there can be any number of compressors and turbines up to a maximum of five each, along with any specified number of intervening intercoolers and reheaters. A recuperator can be included in the system and turbine coolant flow can be accounted for. The combustion-gas thermodynamic properties are valid for any fuel consisting of hydrogen and/or carbon only. The program should be used with maximum temperatures no higher than about 2000 K (3140 degrees Fahrenheit) because molecular dissociation is not included in the stoichiometry. Improvements in cycle performance resulting from the use of intercooling, reheating, and recuperation can also be determined. This program has been implemented on the IBM 7094.

  5. Quality factors in the life cycle of software oriented to safety systems in nuclear power plants

    International Nuclear Information System (INIS)

    The inclusion of software in safety related systems for nuclear power plants, makes it necessary to include the software quality assurance concept. The software quality can be defined as the adjustment degree between the software and the specified requirements and user expectations. To guarantee a certain software quality level it is necessary to make a systematic and planned set of tasks, that constitute a software quality guaranty plan. The application of such a plan involves activities that should be performed all along the software life cycle, and that can be evaluated through the so called quality factors, due to the fact that the quality itself cannot be directly measured, but indirectly as some of it manifestations. In this work, a software life cycle model is proposed, for nuclear power plant safety related systems. A set os software quality factors is also proposed , with its corresponding classification according to the proposed model. (author)

  6. Report on emergency electrical power supply systems for nuclear fuel cycle and reactor facilities security systems

    International Nuclear Information System (INIS)

    The report includes information that will be useful to those responsible for the planning, design and implementation of emergency electric power systems for physical security and special nuclear materials accountability systems. Basic considerations for establishing the system requirements for emergency electric power for security and accountability operations are presented. Methods of supplying emergency power that are available at present and methods predicted to be available in the future are discussed. The characteristics of capacity, cost, safety, reliability and environmental and physical facility considerations of emergency electric power techniques are presented. The report includes basic considerations for the development of a system concept and the preparation of a detailed system design

  7. Report on emergency electrical power supply systems for nuclear fuel cycle and reactor facilities security systems

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    The report includes information that will be useful to those responsible for the planning, design and implementation of emergency electric power systems for physical security and special nuclear materials accountability systems. Basic considerations for establishing the system requirements for emergency electric power for security and accountability operations are presented. Methods of supplying emergency power that are available at present and methods predicted to be available in the future are discussed. The characteristics of capacity, cost, safety, reliability and environmental and physical facility considerations of emergency electric power techniques are presented. The report includes basic considerations for the development of a system concept and the preparation of a detailed system design.

  8. Passive residual energy utilization system in thermal cycles on water-cooled power reactors

    International Nuclear Information System (INIS)

    This work presents a concept of a residual energy utilization in nuclear plants thermal cycles. After taking notice of the causes of the Fukushima nuclear plant accident, an idea arose to adapt a passive thermal circuit as part of the ECCS (Emergency Core Cooling System). One of the research topics of IEAv (Institute for Advanced Studies), as part of the heat conversion of a space nuclear power system is a passive multi fluid turbine. One of the main characteristics of this device is its passive capability of staying inert and be brought to power at moments notice. During the first experiments and testing of this passive device, it became clear that any small amount of gas flow would generate power. Given that in the first stages of the Fukushima accident and even during the whole event there was plenty availability of steam flow that would be the proper condition to make the proposed system to work. This system starts in case of failure of the ECCS, including loss of site power, loss of diesel generators and loss of the battery power. This system does not requires electricity to run and will work with bleed steam. It will generate enough power to supply the plant safety system avoiding overheating of the reactor core produced by the decay heat. This passive system uses a modified Tesla type turbine. With the tests conducted until now, it is possible to ensure that the operation of this new turbine in a thermal cycle is very satisfactory and it performs as expected. (author)

  9. Passive residual energy utilization system in thermal cycles on water-cooled power reactors

    Energy Technology Data Exchange (ETDEWEB)

    Placco, Guilherme M.; Guimaraes, Lamartine N.F., E-mail: placco@ieav.cta.br, E-mail: guimarae@ieav.cta.br [Instituto de Estudos Avancados (IEAV/DCTA) Sao Jose dos Campos, SP (Brazil); Santos, Rubens S. dos, E-mail: rsantos@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN -RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    This work presents a concept of a residual energy utilization in nuclear plants thermal cycles. After taking notice of the causes of the Fukushima nuclear plant accident, an idea arose to adapt a passive thermal circuit as part of the ECCS (Emergency Core Cooling System). One of the research topics of IEAv (Institute for Advanced Studies), as part of the heat conversion of a space nuclear power system is a passive multi fluid turbine. One of the main characteristics of this device is its passive capability of staying inert and be brought to power at moments notice. During the first experiments and testing of this passive device, it became clear that any small amount of gas flow would generate power. Given that in the first stages of the Fukushima accident and even during the whole event there was plenty availability of steam flow that would be the proper condition to make the proposed system to work. This system starts in case of failure of the ECCS, including loss of site power, loss of diesel generators and loss of the battery power. This system does not requires electricity to run and will work with bleed steam. It will generate enough power to supply the plant safety system avoiding overheating of the reactor core produced by the decay heat. This passive system uses a modified Tesla type turbine. With the tests conducted until now, it is possible to ensure that the operation of this new turbine in a thermal cycle is very satisfactory and it performs as expected. (author)

  10. Space Power System Modeling with EBAL

    International Nuclear Information System (INIS)

    Pratt and Whitney Rocket dyne's Engine Balance (EBAL) thermal/fluid system code has been expanded to model nuclear power closed Brayton cycle (CBC) power conversion systems. EBAL was originally developed to perform design analysis of hypersonic vehicle propellant and thermal management systems analysis. Later, it was adapted to rocket engine cycles. The new version of EBAL includes detailed, physics-based models of all key CBC system components. Some component examples are turbo-alternators, heat exchangers, heat pipe radiators, and liquid metal pumps. A liquid metal cooled reactor is included and a gas cooled reactor model is in work. Both thermodynamic and structural analyses are performed for each component. EBAL performs steady-state design analysis with optimization as well as off-design performance analysis. Design optimization is performed both at the component level by the component models and on the system level with a global optimizer. The user has the option to manually drive the optimization process or run parametric analysis to better understand system trade-off. Although recent EBAL developments have focused on a CBC conversion system, the code is easily extendible to other power conversion cycles. This new, more powerful version of EBAL allows for rapid design analysis and optimization of space power systems. A notional example of EBAL's capabilities is included. (authors)

  11. Draft report: application of organic Rankine cycle heat recovery systems to diesel powered marine vessels

    Energy Technology Data Exchange (ETDEWEB)

    1977-07-15

    The analysis and results of an investigation of the application of organic Rankine cycle heat recovery systems to diesel-powered marine vessels are described. The program under which this study was conducted was sponsored jointly by the US Energy Research and Development Administration, the US Navy, and the US Maritime Administration. The overall objective of this study was to investigate diesel bottoming energy recovery systems, currently under development by three US concerns, to determine the potential for application to marine diesel propulsion and auxiliary systems. The study primarily focused on identifying the most promising vessel applications (considering vessel type, size, population density, operational duty cycle, etc.) so the relative economic and fuel conservation merits of energy recovery systems could be determined and assessed. Vessels in the current fleet and the projected 1985 fleet rated at 1000 BHP class and above were investigated.

  12. Working fluids of a low-temperature geothermally-powered Rankine cycle for combined power and heat generation system

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A novel combined power and heat generation system was investigated in this study. This system consists of a low-temperature geothermally-powered organic Rankine cycle (ORC) subsystem, an intermediate heat exchanger and a commercial R134a-based heat pump subsystem. The advantages of the novel combined power and heat generation system are free of using additional cooling water circling system for the power generation subsystem as well as maximizing the use of thermal energy in the low-temperature geothermal source. The main purpose is to identify suitable working fluids (wet, isentropic and dry flu-ids) which may yield high PPR (the ratio of power produced by the power generation subsystem to power consumed by the heat pump subsystem) value and QQR (the ratio of heat supplied to the user to heat produced by the geothermal source) value. Parameters under investigation were evaporating temperature, PPR value and QQR value. Results indicate that there exits an optimum evaporating temperature to maximize the PPR value and minimize the QQR value at the same time for individual fluid. And dry fluids show higher PPR values but lower QQR values. NH3 and R152a outstand among wet fluids. R134a out-stands among isentropic fluids. R236ea, R245ca, R245fa, R600 and R600a outstand among dry fluids. R236ea shows the highest PPR value among the recommended fluids.

  13. The performance of solar thermal electric power systems employing small heat engines

    Science.gov (United States)

    Pons, R. L.

    1980-01-01

    The paper presents a comparative analysis of small (10 to 100 KWe) heat engines for use with a solar thermal electric system employing the point-focusing, distributed receiver (PF-DR) concept. Stirling, Brayton, and Rankine cycle engines are evaluated for a nominal overall system power level of 1 MWe, although the concept is applicable to power levels up to at least 10 MWe. Multiple concentrators are electrically connected to achieve the desired plant output. Best performance is achieved with the Stirling engine, resulting in a system Levelized Busbar Energy Cost of just under 50 mills/kWH and a Capital Cost of $900/kW, based on the use of mass-produced components. Brayton and Rankine engines show somewhat less performance but are viable alternatives with particular benefits for special applications. All three engines show excellent performance for the small community application.

  14. Regulation Law of Turbine and Generator in Organic Rankine Cycle Power Generation Experimental System

    Institute of Scientific and Technical Information of China (English)

    潘利生; 王怀信; 史维秀

    2014-01-01

    In the performance experiment of organic Rankine cycle power generation experimental system, the load-resistance-regulation method is one of the most important regulation methods. However, the regulation law has not been clear enough to guide the experiment, which is unfavorable to the experimental research on organic Rankine cy-cle. In this paper the regulation law of turbine and generator by the load-resistance-regulation method is studied theo-retically and experimentally. The results show that when the thermal cycle parameters keep constant, the turbine speed increases with the increase of load resistance and there is a maximum value of transmission-generator efficiency with the variation of the turbine speed; when the turbine speed and generator speed keep constant, the transmission-generator efficiency decreases and gradually tends to zero with the increase of load resistance.

  15. Design of a power conversion system for an indirect cycle, helium cooled pebble bed reactor system

    International Nuclear Information System (INIS)

    A design is presented for the turbomachinery for an indirect cycle, closed, helium cooled modular pebble bed reactor system. The design makes use of current technology and will operate with an overall efficiency of 45%. The design uses an intermediate heat exchanger which isolated the reactor cycle from the turbomachinery. This design excludes radioactive fission products from the turbomachinery. This minimizes the probability of an air ingress accident and greatly simplifies maintenance. (author)

  16. The universal power and efficiency characteristics for irreversible reciprocating heat engine cycles

    International Nuclear Information System (INIS)

    The performance of irreversible reciprocating heat engine cycles with heat transfer loss and friction-like term loss is analysed using finite-time thermodynamics. The universal relations between the power output and the compression ratio, between the thermal efficiency and the compression ratio, and the optimal relation between power output and the efficiency of the cycles are derived. Moreover, analysis and optimization of the model were carried out in order to investigate the effect of cycle processes on the performance of the cycle using numerical examples. The results obtained herein include the performance characteristics of irreversible reciprocating Diesel, Otto, Atkinson and Brayton cycles

  17. Design of intermediate heat exchanger for the HTGR-closed cycle gas turbine power generation system

    International Nuclear Information System (INIS)

    High thermal efficiency can be achieved in a power generation system, which couples a high-temperature gas-cooled reactor(HTGR) with a closed cycle gas turbine(GT). There are three possible systems such as a direct cycle(DC), an indirect cycle(IDC) and an indirect gas-steam combined cycle(IDCC). An intermediate heat exchanger(IHX) is needed in the IDC or in the IDCC. However, the size of IHX is too large for a reasonable design and it has become one of the most important issues. Then, a design has been undertaken based on the experience of the IHX in the HTTR though as a material of heat transfer tubes, a Ni-Cr-W superalloy with the highest strength at temperature was adopted instead of Hastelloy XR used in the HTTR. First, by parametric design studies, the optimum design parameters have been examined for a heat duty of 150 MW. Then, the IHX of 315 MW has been designed specifically and its dimensions and structures were determined. The IHX was clarified to be capable of fabrication at least in the case of IDCC. The results of parametric studies are useful to make a rough estimate for the other cases and some examples are shown. (author)

  18. Sensitivity analysis of system parameters on the performance of the Organic Rankine Cycle system for binary-cycle geothermal power plants

    International Nuclear Information System (INIS)

    The main purpose of this paper is to analyze the sensitivity of system parameters to the performance of the Organic Rankine Cycle (ORC) system quantitatively. A thermodynamic model of the ORC system for binary-cycle geothermal power plants has been developed and verified. The system parameters, such as working fluid, superheat temperature, pinch temperature difference in evaporator and condenser, evaporating temperature, the isentropic efficiencies of the cycle pump and radial inflow turbine are selected as six factors for orthogonal design. The order of factors sensitivity on performance indices of the net power output of the ORC system, the thermal efficiency, the size parameter of radial inflow turbine, the power decrease factor of the pump and the total heat transfer capacity are determined by the range obtained from the orthogonal design. At different geothermal temperatures, the ranges of the six factors corresponding to performance indices are analyzed respectively. The results show that the geothermal temperature influences the range of the factors to the net power output, SP factor of radial inflow turbine, and the total heat transfer capacity, but it has no effect for the range of the factors for the thermal efficiency and the power decrease factor of the pump. The evaporating temperature is always the primary or secondary factor that influence the thermodynamic and economic performance of the ORC system. This study would provide useful references for determining the proper design variables in the performance optimization of the ORC system at different geothermal temperatures. - Highlights: • Evaporating temperature has significant effect on performance of ORC system. • Order of system parameters' sensitivity to the performance of ORC is revealed. • Effect of system parameters on performance indices vary with geothermal temperature. • Geothermal temperature has no effect on range of six factors to the size of turbine

  19. Key Factors Influencing the Decision on the Number of Brayton Units for the Prometheus Space Reactor

    Science.gov (United States)

    Ashcroft, John; Belanger, Sean; Burdge, Wayne; Clementoni, Eric; Jensen, Krista; Proctor, N. Beth; Zemo-Fulkerson, Annie

    2007-01-01

    The Naval Reactors (NR) Program and its DOE Laboratories, KAPL and Bettis, were assigned responsibility to develop space reactor systems for the Prometheus Program. After investigating all of the potential reactor and energy conversion options, KAPL and Bettis selected a direct gas Brayton system as the reference approach for the nuclear electric propulsion missions, including the Jupiter Icy Moons Orbiter (JIMO). In order to determine the optimal plant architecture for the direct gas system, KAPL and Bettis investigated systems with one or two active Brayton units and up to two spare units. No final decision was made on the optimal system configuration for the NEP gas-Brayton system prior to closeout of the project. The two most promising options appear to be a single system without spares and a three Brayton system with two operating units, each producing half of the required load, with a single spare unit. The studies show that a single Brayton system, without spares, offers the lowest mass system, with potential for lower operating temperature, and a minimum of system and operational complexity. The lower required mass and increased system efficiency inherent in the single Brayton system may be exploited to satisfy other design objectives such as reduced reactor and radiator operating temperatures. While Brayton system lifetimes applicable to a JIMO or other nuclear electric propulsion (NEP) mission have not been demonstrated, there is no fundamental limit on the lifetime of the Brayton hardware. Use of additional Brayton units with installed spares will allow for continued operation in the event of a failure of an individual Brayton unit. However, preliminary system reliability evaluations do not point to any substantial reliability benefit provided by carrying spare Brayton units. If a spare unit is used, operating two of the units at full power with an unpowered spare proved more efficient than operating all three units at a reduced power and temperature

  20. Brayton heat exchange unit development program

    Science.gov (United States)

    Morse, C. J.; Richard, C. E.; Duncan, J. D.

    1971-01-01

    A Brayton Heat Exchanger Unit (BHXU), consisting of a recuperator, a heat sink heat exchanger and a gas ducting system, was designed, fabricated, and tested. The design was formulated to provide a high performance unit suitable for use in a long-life Brayton-cycle powerplant. A parametric analysis and design study was performed to establish the optimum component configurations to achieve low weight and size and high reliability, while meeting the requirements of high effectiveness and low pressure drop. Layout studies and detailed mechanical and structural design were performed to obtain a flight-type packaging arrangement. Evaluation testing was conducted from which it is estimated that near-design performance can be expected with the use of He-Xe as the working fluid.

  1. Technology for Bayton-cycle powerplants using solar and nuclear energy

    Science.gov (United States)

    English, R. E.

    1986-01-01

    Brayton cycle gas turbines have the potential to use either solar heat or nuclear reactors for generating from tens of kilowatts to tens of megawatts of power in space, all this from a single technology for the power generating system. Their development for solar energy dynamic power generation for the space station could be the first step in an evolution of such powerplants for a very wide range of applications. At the low power level of only 10 kWe, a power generating system has already demonstrated overall efficiency of 0.29 and operated 38 000 hr. Tests of improved components show that these components would raise that efficiency to 0.32, a value twice that demonstrated by any alternate concept. Because of this high efficiency, solar Brayton cycle power generators offer the potential to increase power per unit of solar collector area to levels exceeding four times that from photovoltaic powerplants using present technology for silicon solar cells. The technologies for solar mirrors and heat receivers are reviewed and assessed. This Brayton technology for solar powerplants is equally suitable for use with the nuclear reactors. The available long time creep data on the tantalum alloy ASTAR-811C show that such Brayton cycles can evolve to cycle peak temperatures of 1500 K (2240 F). And this same technology can be extended to generate 10 to 100 MW in space by exploiting existing technology for terrestrial gas turbines in the fields of both aircraft propulsion and stationary power generation.

  2. Network Theory Integrated Life Cycle Assessment for an Electric Power System

    Directory of Open Access Journals (Sweden)

    Heetae Kim

    2015-08-01

    Full Text Available In this study, we allocate Greenhouse gas (GHG emissions of electricity transmission to the consumers. As an allocation basis, we introduce energy distance. Energy distance takes the transmission load on the electricity energy system into account in addition to the amount of electricity consumption. As a case study, we estimate regional GHG emissions of electricity transmission loss in Chile. Life cycle assessment (LCA is used to estimate the total GHG emissions of the Chilean electric power system. The regional GHG emission of transmission loss is calculated from the total GHG emissions. We construct the network model of Chilean electric power grid as an undirected network with 466 nodes and 543 edges holding the topology of the power grid based on the statistical record. We analyze the total annual GHG emissions of the Chilean electricity energy system as 23.07 Mt CO2-eq. and 1.61 Mt CO2-eq. for the transmission loss, respectively. The total energy distance for the electricity transmission accounts for 12,842.10 TWh km based on network analysis. We argue that when the GHG emission of electricity transmission loss is estimated, the electricity transmission load should be separately considered. We propose network theory as a useful complement to LCA analysis for the complex allocation. Energy distance is especially useful on a very large-scale electric power grid such as an intercontinental transmission network.

  3. Comparative Evaluation of Biomass Power Generation Systems in China Using Hybrid Life Cycle Inventory Analysis

    Directory of Open Access Journals (Sweden)

    Huacai Liu

    2014-01-01

    Full Text Available There has been a rapid growth in using agricultural residues as an energy source to generate electricity in China. Biomass power generation (BPG systems may vary significantly in technology, scale, and feedstock and consequently in their performances. A comparative evaluation of five typical BPG systems has been conducted in this study through a hybrid life cycle inventory (LCI approach. Results show that requirements of fossil energy savings, and greenhouse gas (GHG emission reductions, as well as emission reductions of SO2 and NOx, can be best met by the BPG systems. The cofiring systems were found to behave better than the biomass-only fired system and the biomass gasification systems in terms of energy savings and GHG emission reductions. Comparing with results of conventional process-base LCI, an important aspect to note is the significant contribution of infrastructure, equipment, and maintenance of the plant, which require the input of various types of materials, fuels, services, and the consequent GHG emissions. The results demonstrate characteristics and differences of BPG systems and help identify critical opportunities for biomass power development in China.

  4. Optimization of the oxidant supply system for combined cycle MHD power plants

    International Nuclear Information System (INIS)

    An in-depth study was conducted to determine what, if any, improvements could be made on the oxidant supply system for combined cycle MHD power plants which could be reflected in higher thermal efficiency and a reduction in the cost of electricity, COE. A systematic analysis of air separation process varitions which showed that the specific energy consumption could be minimized when the product stream oxygen concentration is about 70 mole percent was conducted. The use of advanced air compressors, having variable speed and guide vane position control, results in additional power savings. The study also led to the conceptual design of a new air separation process, sized for a 500 MW sub e MHD plant, referred to a internal compression is discussed. In addition to its lower overall energy consumption, potential capital cost savings were identified for air separation plants using this process when constructed in a single large air separation train rather than multiple parallel trains, typical of conventional practice

  5. Development of advanced off-design models for supercritical carbon dioxide power cycles

    International Nuclear Information System (INIS)

    In the search for increased efficiency of utility-scale electricity generation, Brayton cycles operating with supercritical carbon dioxide (S-CO2) have found considerable interest. There are two main advantages of a S-CO2 Brayton cycle compared to a Rankine cycle: 1) equal or greater thermal efficiencies can be realized using significantly smaller turbomachinery, and 2) heat rejection is not limited by the saturation temperature of the working fluid, which has the potential to reduce or completely eliminate the need for cooling water and instead allow dry cooling. While dry cooling is especially advantageous for power generation in arid climates, a reduction of water consumption in any location will be increasingly beneficial as tighter environmental regulations are enacted in the future. Because daily and seasonal weather variations may result in a plant operating away from its design point, models that are capable of predicting the off-design performance of S-CO2 power cycles are necessary for characterizing and evaluating cycle configurations and turbomachinery designs on an annual basis. To this end, an off-design model of a recuperated Brayton cycle was developed based on the radial turbomachinery currently being investigated by Sandia National Laboratory. (authors)

  6. Quantum-mechanical Brayton engine working with a particle in a one-dimensional harmonic trap

    Science.gov (United States)

    Wang, H.

    2013-05-01

    Based on the quantum version of thermodynamic processes, a quantum-mechanical Brayton engine model has been established. Expressions for the power output and efficiency of the engine are derived. Some fundamental optimal relations and general performance characteristic curves of the cycle are obtained. Furthermore, we note that it is possible to resist the reduction in efficiency, caused by compression of the adiabatic process, by decreasing the amount of energy levels of the quantum system. The results obtained here will provide theoretical guidance for the design of some new quantum-mechanical engines.

  7. Design and optimization of a single stage centrifugal compressor for a solar dish-Brayton system

    Science.gov (United States)

    Wang, Yongsheng; Wang, Kai; Tong, Zhiting; Lin, Feng; Nie, Chaoqun; Engeda, Abraham

    2013-10-01

    According to the requirements of a solar dish-Brayton system, a centrifugal compressor stage with a minimum total pressure ratio of 5, an adiabatic efficiency above 75% and a surge margin more than 12% needs to be designed. A single stage, which consists of impeller, radial vaned diffuser, 90° crossover and two rows of axial stators, was chosen to satisfy this system. To achieve the stage performance, an impeller with a 6:1 total pressure ratio and an adiabatic efficiency of 90% was designed and its preliminary geometry came from an in-house one-dimensional program. Radial vaned diffuser was applied downstream of the impeller. Two rows of axial stators after 90° crossover were added to guide the flow into axial direction. Since jet-wake flow, shockwave and boundary layer separation coexisted in the impeller-diffuser region, optimization on the radius ratio of radial diffuser vane inlet to impeller exit, diffuser vane inlet blade angle and number of diffuser vanes was carried out at design point. Finally, an optimized centrifugal compressor stage fulfilled the high expectations and presented proper performance. Numerical simulation showed that at design point the stage adiabatic efficiency was 79.93% and the total pressure ratio was 5.6. The surge margin was 15%. The performance map including 80%, 90% and 100% design speed was also presented.

  8. The nuclear power cycle

    International Nuclear Information System (INIS)

    Fifty years after the first nuclear reactor come on-line, nuclear power is fourth among the world's primary energy sources, after oil, coal and gas. In 2002, there were 441 reactors in operation worldwide. The United States led the world with 104 reactors and an installed capacity of 100,000 MWe, or more than one fourth of global capacity. Electricity from nuclear energy represents 78% of the production in France, 57% in Belgium, 46% in Sweden, 40% in Switzerland, 39% in South Korea, 34% in Japan, 30% in Germany, 30% in Finland, 26% in Spain, 22% in Great Britain, 20% in the United States and 16% in Russia. Worldwide, 32 reactors are under construction, including 21 in Asia. This information document presents the Areva activities in the nuclear power cycle: the nuclear fuel, the nuclear reactors, the spent fuel reprocessing and recycling and nuclear cleanup and dismantling. (A.L.B.)

  9. Exergy Analysis of Combined Cycle Power Plant: NTPC Dadri, India

    Directory of Open Access Journals (Sweden)

    Arvind Kumar Tiwari

    2012-12-01

    Full Text Available The aim of the present paper is to exergy analysis of combined Brayton/Rankine power cycle of NTPC Dadri India. Theoretical exergy analysis is carried out for different components of dadri combined cycle power plant which consists of a gas turbine unit, heat recovery steam generator without extra fuel consumption and steam turbine unit. The results pinpoint that more exergy losses occurred in the gas turbine combustion chamber. Its reached 35% of the total exergy losses while the exergy losses in other plant components are between 7% -21% of the total exergy losses at 1400o C turbine inlet temperature and pressure ratio 10 .This paper also considered the effect of the pressure ratio, turbine inlet temperature, pressure drop in combustion chamber and heat recovery steam generator on the exergy losses in the plant, there are a clear effects in the exergy losses when changing pressure ratio, turbine inlet temperature.

  10. Isotope Brayton ground demonstration testing and flight qualification. Volume 1. Technical program

    Energy Technology Data Exchange (ETDEWEB)

    1974-12-09

    A program is proposed for the ground demonstration, development, and flight qualification of a radioisotope nuclear heated dynamic power system for use on space missions beginning in the 1980's. This type of electrical power system is based upon and combines two aerospace technologies currently under intense development; namely, the MHW isotope heat source and the closed Brayton cycle gas turbine. This power system represents the next generation of reliable, efficient economic electrical power equipment for space, and will be capable of providing 0.5 to 2.0 kW of electric power to a wide variety of spacecraft for earth orbital and interplanetary missions. The immediate design will be based upon the requirements for the Air Force SURVSATCOM mission. The proposal is presented in three volumes plus an Executive Summary. This volume describes the tasks in the technical program.

  11. Thermal analysis of heat and power plant with high temperature reactor and intermediate steam cycle

    Directory of Open Access Journals (Sweden)

    Fic Adam

    2015-03-01

    Full Text Available Thermal analysis of a heat and power plant with a high temperature gas cooled nuclear reactor is presented. The main aim of the considered system is to supply a technological process with the heat at suitably high temperature level. The considered unit is also used to produce electricity. The high temperature helium cooled nuclear reactor is the primary heat source in the system, which consists of: the reactor cooling cycle, the steam cycle and the gas heat pump cycle. Helium used as a carrier in the first cycle (classic Brayton cycle, which includes the reactor, delivers heat in a steam generator to produce superheated steam with required parameters of the intermediate cycle. The intermediate cycle is provided to transport energy from the reactor installation to the process installation requiring a high temperature heat. The distance between reactor and the process installation is assumed short and negligable, or alternatively equal to 1 km in the analysis. The system is also equipped with a high temperature argon heat pump to obtain the temperature level of a heat carrier required by a high temperature process. Thus, the steam of the intermediate cycle supplies a lower heat exchanger of the heat pump, a process heat exchanger at the medium temperature level and a classical steam turbine system (Rankine cycle. The main purpose of the research was to evaluate the effectiveness of the system considered and to assess whether such a three cycle cogeneration system is reasonable. Multivariant calculations have been carried out employing the developed mathematical model. The results have been presented in a form of the energy efficiency and exergy efficiency of the system as a function of the temperature drop in the high temperature process heat exchanger and the reactor pressure.

  12. Carbon dioxide power cycles using liquid natural gas as heat sink

    International Nuclear Information System (INIS)

    Liquefied natural gas (LNG) is recognized as a source of usable cryogenic exergy for power cycles. The performance of conventional cycles are calculated. A binary steam-Organic Rankine Cycle (ORC) at 550 deg. C has an efficiency of about 52%, somewhat higher than that of a nitrogen Brayton cycle (50.7% at 700 deg. C). Carbon dioxide is recognized as an almost ideal medium for implementing single fluid condensation cycles. Its proven practical use both at low temperature (by the refrigeration industry) and at high temperature (by the nuclear reactor industry) makes it suitable for direct utilization without any extended preliminary research. A carbon dioxide cycle in its basic configuration featuring a pump, a regenerator, a heater and a condenser is much simpler than the binary steam-ORC cycle but has a lower efficiency (around 47%). All condensing cycles (ORC,CO2,...) exhibit a limited capability of exploiting the whole cryogenic exergy of LNG in that they cannot heat the natural gas at temperatures above the condensation temperature. This drawback is fully overcome in nitrogen Brayton cycles which can heat LNG up to ambient temperature. Slightly modifying the basic CO2 cycle so that it can partially use free thermal energy from sea water increases efficiency to 51%. Multiple condensation cycles allow a better overall performance at the cost of a more complex layout. Compound CO2 cycles, featuring also a gas compressor, exhibit an improved thermodynamics by reducing the temperature difference within the regenerator, with the result of increasing the overall efficiency at values better than those of both binary and Brayton cycles. At 600 deg. C top temperature, for example, a compound cycle at 100 bar maximum pressure has an efficiency of 55.3% (52.3% for a binary steam-ORC cycle at 550 deg. C, 150 bar steam parameters; 46.5% for the nitrogen cycle at 600 deg. C top temperature).

  13. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part B

    DEFF Research Database (Denmark)

    La Seta, Angelo; Meroni, Andrea; Andreasen, Jesper Graa; Pierobon, Leonardo; Persico, Giacomo; Haglind, Fredrik

    2016-01-01

    due to the peculiar physical properties of the working fluid and the gas-dynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders combine small enthalpy drops with large expansion ratios. These features yield turbine designs with few highly...... cost of the turbine optimization is tackled by building a model which gives the optimal preliminary design of an axial-flow turbine as a function of the cycle conditions. This allows for estimating the optimal expander performance for each operating condition of interest. The test case is the...... power output of 8.3% compared to the case when the turbine efficiency is assumed to be 80%. This work also demonstrates that this approach can support the plant designer in the selection of the optimal size of the organic Rankine cycle unit when multiple exhaust gas streams are available....

  14. Limitations of power conversion systems under transient loads and impact on the pulsed tokamak power reactor

    Science.gov (United States)

    Sager, G. T.; Wong, C. P. C.; Kapich, D. D.; McDonald, C. F.; Schleicher, R. W.

    1993-11-01

    The impact of cyclic loading of the power conversion system of a helium-cooled, pulsed tokamak power plant is assessed. Design limits of key components of heat transport systems employing Rankine and Brayton thermodynamic cycles are quantified based on experience in gas-cooled fission reactor design and operation. Cyclic loads due to pulsed tokamak operation are estimated. Expected performance of the steam generator is shown to be incompatible with pulsed tokamak operation without load leveling thermal energy storage. The close cycle gas turbine is evaluated qualitatively based on performance of existing industrial and aeroderivative gas turbines. Advances in key technologies which significantly improve prospects for operation with tokamak fusion plants are reviewed.

  15. An advanced oxy-fuel power cycle with high efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Gou, C.; Hong, H. [University of Science and Technology, Beijing (China). Mechanical School; Cai, R. [Chinese Academy of Sciences, Beijing (China). Institute of Engineering Thermophysics

    2006-07-01

    In this article, an innovative oxy-fuel power cycle is proposed as a promising CO{sub 2} emission mitigation solution. It includes two cases with different characteristics in the cycle configuration. Case 1 basically consists of a water steam Rankine cycle and a steam-CO{sub 2} recuperative-reheat cycle. Case 2 integrates some characteristics of Case 1 and a top Brayton cycle. The thermodynamic performances for the design conditions of these two cases were analysed using the advanced process simulator Aspen Plus and the results are given in detail. The corresponding exergy loss analyses were carried out to gain an understanding of the loss distribution. The MATIANT cycle, the CES cycle, and the GRAZ cycle were also evaluated as references. The results demonstrate that the proposed cycle has notable advantages in thermal efficiency, specific work, and technical feasibility compared with the reference cycles. For example, the thermal efficiency of Case 2 is 6.58 percentage points higher than that of the MATIANT cycle. (author)

  16. Alternative analysis to increase the power in combined-cycle power plants; Analisis de alternativas para el incremento de potencia en plantas termoelectricas de Ciclo Combinado

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco Cruz, Hector; Arriola Medellin, Alejandro M. [Gerencia de Procesos Termicos, Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: hpacheco@iie.org.mx; aarriola@iie.org.mx

    2010-11-15

    The electricity industry traditionally had two thermodynamic cycles for power generation: conventional steam turbine (Rankine cycle) used to supply a base load during the day, and gas turbines (Brayton cycle), for its speed response, normally used to cover peak loads. However, to provide variable peak loads, the gas turbine, as a volumetric machine is affected by the change in air density by changing the combustion temperature. This paper shows the scheme of integration of both systems, that it's known as combined cycle and the different options that would have these power plants, to maintain or increase their power in variable ambient conditions. It analyzes different options, such as: 1. Supplementary fire in the stove. 2. Air cooling intake in the gas turbine (evaporation system or mechanical system). 3. Steam injection in the combustion chamber. [Spanish] La industria electrica tradicionalmente a contado con dos ciclos termodinamicos para generacion electrica: las turbinas convencionales de vapor (ciclo de Rankine) se utilizan para suministrar una carga base durante el dia, y las turbinas de gas (ciclo de Brayton), por su rapidez de respuesta, se utilizan normalmente para cubrir las cargas pico. Sin embargo, para suministrar las cargas variables pico, la turbina a gas, por ser una maquina volumetrica, se ve afectada por el cambio de la densidad del aire de combustion al cambiar la temperatura ambiente. En este trabajo se muestra el esquema de integracion de ambos sistemas, en lo que se conoce como ciclo combinado y las diferentes opciones que tendrian estas plantas de generacion electrica para mantener o incrementar su potencia en condiciones ambiente variable. Para ello se analizan diferentes opciones, tales como: 1.- Combustion suplementaria en el recuperador de calor. 2.- Enfriamiento del aire de admision a la turbina de gas (mediante un sistema de evaporacion o mediante un sistema mecanico). 3.- Inyeccion de vapor a la camara de combustion. Palabras

  17. Thermodynamic design of 10 kW Brayton cryocooler for HTS cable

    Science.gov (United States)

    Chang, Ho-Myung; Park, C. W.; Yang, H. S.; Sohn, Song Ho; Lim, Ji Hyun; Oh, S. R.; Hwang, Si Dole

    2012-06-01

    Thermodynamic design of Brayton cryocooler is presented as part of an ongoing governmental project in Korea, aiming at 1 km HTS power cable in the transmission grid. The refrigeration requirement is 10 kW for continuously sub-cooling liquid nitrogen from 72 K to 65 K. An ideal Brayton cycle for this application is first investigated to examine the fundamental features. Then a practical cycle for a Brayton cryocooler is designed, taking into account the performance of compressor, expander, and heat exchangers. Commercial software (Aspen HYSYS) is used for simulating the refrigeration cycle with real fluid properties of refrigerant. Helium is selected as a refrigerant, as it is superior to neon in thermodynamic efficiency. The operating pressure and flow rate of refrigerant are decided with a constraint to avoid the freezing of liquid nitrogen

  18. HTR-Based Power Plants’ Performance Analysis Applied on Conventional Combined Cycles

    Directory of Open Access Journals (Sweden)

    José Carbia Carril

    2015-01-01

    Full Text Available In high temperature reactors including gas cooled fast reactors and gas turbine modular helium reactors (GT-MHR specifically designed to operate as power plant heat sources, efficiency enhancement at effective cost under safe conditions can be achieved. Mentioned improvements concern the implementation of two cycle structures: (a, a stand alone Brayton operating with helium and a stand alone Rankine cycle (RC with regeneration, operating with carbon dioxide at ultrasupercritical pressure as working fluid (WF, where condensation is carried out at quasicritical conditions, and (b, a combined cycle (CC, in which the topping closed Brayton cycle (CBC operates with helium as WF, while the bottoming RC is operated with one of the following WFs: carbon dioxide, xenon, ethane, ammonia, or water. In both cases, an intermediate heat exchanger (IHE is proposed to provide thermal energy to the closed Brayton or to the Rankine cycles. The results of the case study show that the thermal efficiency, through the use of a CC, is slightly improved (from 45.79% for BC and from 50.17% for RC to 53.63 for the proposed CC with He-H2O operating under safety standards.

  19. A preliminary study of the modified Ericsson for space power

    Science.gov (United States)

    Berner, J.; Louis, J. F.; Juhasz, A.

    1985-01-01

    Simple modifications of the Ericsson cycle are analyzed for their application as high power, compact and reliable space power systems. They use the same components as the technologically advanced and reliable Brayton system. These modifications approximate the Ericsson cycle's isothermal expansion by several stages of expansion with reheat and the isothermal compression by several compression stages with intercooling. Preliminary cycle analysis including non-ideal components indicates potential advantages in both power per unit area and efficiency over the Brayton system. Evaluation of the system mass indicates a significant mass and radiator area advantage of a Modified Ericsson cycle using one reheat and one expansion stage when a high temperature titanium radiator is used. Whereas the configuration using one reheat and one intercooling with two stages of compression and expansion provided the lowest mass per unit power using a lower temperature aluminum radiator.

  20. Multi-Megawatt Power System Trade Study

    Energy Technology Data Exchange (ETDEWEB)

    Longhurst, Glen Reed; Schnitzler, Bruce Gordon; Parks, Benjamin Travis

    2001-11-01

    As part of a larger task, the Idaho National Engineering and Environmental Laboratory (INEEL) was tasked to perform a trade study comparing liquid-metal cooled reactors having Rankine power conversion systems with gas-cooled reactors having Brayton power conversion systems. This report summarizes the approach, the methodology, and the results of that trade study. Findings suggest that either approach has the possibility to approach the target specific mass of 3-5 kg/kWe for the power system, though it appears either will require improvements to achieve that. Higher reactor temperatures have the most potential for reducing the specific mass of gas-cooled reactors but do not necessarily have a similar effect for liquid-cooled Rankine systems. Fuels development will be the key to higher reactor operating temperatures. Higher temperature turbines will be important for Brayton systems. Both replacing lithium coolant in the primary circuit with gallium and replacing potassium with sodium in the power loop for liquid systems increase system specific mass. Changing the feed pump turbine to an electric motor in Rankine systems has little effect. Key technologies in reducing specific mass are high reactor and radiator operating temperatures, low radiator areal density, and low turbine/generator system masses. Turbine/generator mass tends to dominate overall power system mass for Rankine systems. Radiator mass was dominant for Brayton systems.

  1. Influence of system integration options on the performance of an integrated gasification combined cycle power plant

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Jun; Kim, Young Sik; Cha, Kyu Sang [Graduate School, Inha University, Incheon 402-751 (Korea); Kim, Tong Seop [Dept. of Mechanical Engineering, Inha University, Incheon 402-751 (Korea); Sohn, Jeong L. [School of Aerospace and Mechanical Engineering, Seoul National University, Seoul 151-741 (Korea); Joo, Yong Jin [IGCC Group, Korea Electric Power Research Institute, Daejeon 305-760 (Korea)

    2009-09-15

    An IGCC (integrated gasification combined cycle) plant consists of a power block and a gasifier block, and a smooth integration of these two parts is important. This work has analyzed the influences of the major design options on the performance of an IGCC plant. These options include the method of integrating a gas turbine with an air separation unit and the degree of nitrogen supply from the ASU to the gas turbine combustor. Research focus was given to the effect of each option on the gas turbine operating condition along with plant performance. Initially, an analysis adopting an existing gas turbine without any modifications of its components was performed to examine the influence of two design options on the operability of the gas turbine and performance of the entire IGCC plant. It is shown that a high integration degree, where much of the air required at the air separation unit is supplied by the gas turbine compressor, can be a better option considering both the system performance and operation limitation of the gas turbine. The nitrogen supply enhances system performance, but a high supply ratio can only be acceptable in high integration degree designs. Secondly, the modifications of gas turbine components to resume the operating surge margin, such as increasing the maximum compressor pressure ratio by adding a couple of stages and increasing turbine swallowing capacity, were simulated and their effects on system performance were examined. Modification can be a good option when a low integration degree is to be adopted, as it provides a considerable power increase. (author)

  2. Applied studies in advanced boiler technology for Rankine cycle power systems

    Energy Technology Data Exchange (ETDEWEB)

    Paul, F.W.; Negreanu, M.J.

    1978-02-01

    A study is presented on a new rotational boiler design which has improved passive dynamic response and two-phase flow stability characteristics. A survey of small boiler manufacturers in the United States indicated that currently available designs are based on steady-state operating requirements rather than for dynamic performance. Recent work by EPA and ERDA which addressed boiler designs for mobile automotive Rankine cycle power systems showed that boilers of a monotube or multipass tube configuration design could be developed which were physically compact, but still were subject to the two-phase flow instability problem when coupled within an operating power system. The objectives of this work were to evaluate alternative boiler configurations which would improve boiler dynamic response and also have good two-phase liquid-vapor interface flow stability. The major physical design limitation of any boiler is the small external hot gas heat transfer coefficient. Such a low coefficient requires considerable design enhancements to increase the rate of energy transfer to the circulation system fluid. The rotational boiler is a physical design configuration which addresses this problem. The results of an analytic study using several mathematical model formulations showed that a rotational boiler could have a passive response time constant which was approximately one-half the magnitude for an equivalent single pass monotube boiler. An experimental prototype rotational boiler was designed, manufactured and tested, with the experimental results confirming that the experimental passive response time constants were comparable to the estimates from the analytic models. The experimental boiler operating in two-phase flow was found to be stable and responsive to external inputs. A rotational boiler configuration is a good alternative design configuration for small compact vapor generator designs based on fast transient passive response and two-phase flow stability.

  3. Liquid metal versus gas cooled reactor concepts for a turbo electric powered space vehicle

    International Nuclear Information System (INIS)

    Recent CNES/CEA prospective studies of an orbit transfer vehicule to be launched by ARIANE V, emphasize the advantage of the Brayton cycle over the thermionics and thermoelectricity, in minimizing the total mass of 100 to 300 kWsub(e) power systems under the constraint specific to ARIANE of a radiator area limited to 95 m2. The review of candidate reactor concepts for this application, finally recommends both liquid metal and gas cooled reactors, for their satisfactory adaptation to a reference Brayton cycle and for the available experience from the terrestrial operation of comparable systems

  4. Assessing the Integrated Computerized Maintenance Management System of O&M Company for Combined Cycle Power Station

    OpenAIRE

    Rocel D. Gualberto

    2015-01-01

    This study sought to describe and assess the integrated Computerized Maintenance Management System applied by an Operation and Management (O&M) company to a Combined Cycle Power Station and come up with possible enhancement activities based on the results of the evaluation. The integrated Computerized Maintenance Management System is an electronic database which provides a powerful tool to deal with mechanical maintenance problems. It is a comprehensive approach that directs th...

  5. Super- and Transcritical Fluid Expansions for Next-Generation Energy Conversion Systems

    NARCIS (Netherlands)

    Harinck, J.

    2010-01-01

    The next generation of thermodynamic power cycles offers great potential as the conceptual basis for sustainable energy converters. Examples are the supercritical and superheated Organic Rankine cycle, the transcritical condensation cycle, the supercritical Brayton cycle, the Organic Stirling cycle

  6. Selection of power plant elements for future reactor space electric power systems

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.; Bennett, G.A.; Copper, K.

    1979-09-01

    Various types of reactor designs, electric power conversion equipment, and reject-heat systems to be used in nuclear reactor power plants for future space missions were studied. The designs included gas-cooled, liquid-cooled, and heat-pipe reactors. For the power converters, passive types such as thermoelectric and thermionic converters and dynamic types such as Brayton, potassium Rankine, and Stirling cycles were considered. For the radiators, heat pipes for transfer and radiating surface, pumped fluid for heat transfer with fins as the radiating surface, and pumped fluid for heat transfer with heat pipes as the radiating surface were considered. After careful consideration of weights, sizes, reliabilities, safety, and development cost and time, a heat-pipe reactor design, thermoelectric converters, and a heat-pipe radiator for an experimental program were selected.

  7. Selection of power plant elements for future reactor space electric power systems

    International Nuclear Information System (INIS)

    Various types of reactor designs, electric power conversion equipment, and reject-heat systems to be used in nuclear reactor power plants for future space missions were studied. The designs included gas-cooled, liquid-cooled, and heat-pipe reactors. For the power converters, passive types such as thermoelectric and thermionic converters and dynamic types such as Brayton, potassium Rankine, and Stirling cycles were considered. For the radiators, heat pipes for transfer and radiating surface, pumped fluid for heat transfer with fins as the radiating surface, and pumped fluid for heat transfer with heat pipes as the radiating surface were considered. After careful consideration of weights, sizes, reliabilities, safety, and development cost and time, a heat-pipe reactor design, thermoelectric converters, and a heat-pipe radiator for an experimental program were selected

  8. A stochastic process model for life cycle cost analysis of nuclear power plant systems

    NARCIS (Netherlands)

    Van der Weide, J.A.M.; Pandey, M.D.

    2013-01-01

    The paper presents a general stochastic model to analyze the life cycle cost of an engineering system that is affected by minor but repairable failures interrupting the operation and a major failure that would require the replacement or renewal of the failed system. It is commonly observed that the

  9. Optical cycle power meter

    DEFF Research Database (Denmark)

    2014-01-01

    A bicycle power meter for measuring power generated when riding a bicycle, the power meter comprising a position-sensitive radiation detector (409) attachable to a component of a crank set (404) of bicycle, and a radiation source (408) attachable to the component of the crank set and configured t...

  10. Design Concept of Propulsion System for Nuclear Operated Vessel Adventurer

    Energy Technology Data Exchange (ETDEWEB)

    Halimi, B.; Kim, T. W.; Son, H. M.; Suh, Kune Y. [Seoul National University, Seoul (Korea, Republic of)

    2008-05-15

    This work centers about advantages of nuclear power propulsion with various naval applications such as military surface ship, submarine, and ice breaker. These applications are required to work for a long periods of time on the ocean, where supply of fuel is complicated and sometimes impracticable. A preliminary design concept is presented of the propulsion system for the Nuclear Operated Vessel Adventurer (NOVA). NOVA employs the Battery Omnibus Reactor Integral System (BORIS), a small fast integral reactor cooled by natural circulation and the Modular Optimized Brayton Integral System (MOBIS), a supercritical carbon dioxide (SCO2) driven Brayton cycle, as power converter to the Naval Application Vessel Integral System (NAVIS)

  11. Assessment of generic solar thermal systems for large power applications: analysis of electric power generating costs for systems larger than 10 MWe

    Energy Technology Data Exchange (ETDEWEB)

    Apley, W.J.; Bird, S.P.; Brown, D.R.; Drost, M.K.; Fort, J.A.; Garrett-Price, B.A.; Patton, W.P.; Williams, T.A.

    1980-11-01

    Seven generic types of collectors, together with associated subsystems for electric power generation, were considered. The collectors can be classified into three categories: (1) two-axis tracking (with compound-curvature reflecting surfaces); (2) one-axis tracking (with single-curvature reflecting surfaces); and (3) nontracking (with low-concentration reflecting surfaces). All seven collectors were analyzed in conceptual system configurations with Rankine-cycle engines. In addition, two of the collectors were analyzed with Brayton-cycle engines, and one was analyzed with a Stirling-cycle engine. With these engine options, and the consideration of both thermal and electrical storage for the Brayton-cycle central receiver, 11 systems were formulated for analysis. Conceptual designs developed for the 11 systems were based on common assumptions of available technology in the 1990 to 2000 time frame. No attempt was made to perform a detailed optimization of each conceptual design. Rather, designs best suited for a comparative evaluation of the concepts were formulated. Costs were estimated on the basis of identical assumptions, ground rules, methodologies, and unit costs of materials and labor applied uniformly to all of the concepts. The computer code SOLSTEP was used to analyze the thermodynamic performance characteristics and energy costs of the 11 concepts. Year-long simulations were performed using meteorological and insolation data for Barstow, California. Results for each concept include levelized energy costs and capacity factors for various combinations of storage capacity and collector field size.

  12. Life cycle assessment of primary control provision by battery storage systems and fossil power plants

    OpenAIRE

    Koj, Jan Christian; Stenzel, Peter; Schreiber, Andrea; Hennings, Wilfried; Zapp, Petra; Wrede, Gunnar; Hahndorf, Ina

    2015-01-01

    Increasing renewable energy generation influences the reliability of electric power grids. Thus, there is a demand for new technical units providing ancillary grid services. Intermittent renewable energy sources can be balanced by energy storage devices, especially battery storage systems. By battery systems grid efficiency and reliability as well as power quality can be increased. A further characteristic of battery systems is the ability to respond rapidly and precisely to frequency deviati...

  13. Parametric analysis of a new combined cooling, heating and power system with transcritical CO2 driven by solar energy

    International Nuclear Information System (INIS)

    Highlights: ► The new CCHP system combines a Brayton cycle and a transcritical CO2 refrigeration cycle. ► CO2 is used as the working fluid, which is a natural substance and beneficial to environment. ► The effects of key thermodynamic parameters on the system performance are examined. -- Abstract: In order to utilize renewable energy to meet diverse energy requirements, a new combined cooling, heating and power (CCHP) system is proposed to produce cooling output, heating output and power output simultaneously. This proposed system combines a Brayton cycle and a transcritical CO2 refrigeration cycle with ejector-expansion device, which uses solar energy as the heat source to reduce fossil fuel consumption and alleviate environmental problems. A mathematical model is developed to simulate the new CCHP system with transcritical CO2 driven by solar energy under steady-state conditions, and the thermal efficiency and exergy efficiency are used to evaluate the system performance. The effects of several key thermodynamic parameters on the system performance are examined. The results indicate that increasing turbine inlet pressure and ejector inlet temperature could lower the efficiency of the system, and increasing turbine back pressure and turbine inlet temperature could elevate the efficiency of system. In addition, as ejector back pressure increases, the thermal efficiency of system decreases, but the exergy efficiency increases.

  14. Design consideration of supercritical CO2 power cycle integral experiment loop

    International Nuclear Information System (INIS)

    Supercritical-CO2 Brayton cycle has been recently gaining a lot of attention for the mild temperature (450–650 °C) heat source application due to its high efficiency and compact footprint as the system layout of S–CO2 cycle is simple and small turbomachinery and compact micro-channel heat exchangers are utilized. As CO2 properties behave more like an incompressible fluid near the critical point (30.98 °C, 7.38 MPa), the control of compressor operating condition and stability is the key technology that influences the cycle efficiency. Based on the previous works on the S–CO2 test facilities from various research institutions, a Korean research team designed the SCIEL (Supercritical CO2 Integral Experiment Loop) to achieve higher efficiency with higher pressure ratio with S–CO2 power cycle compared to other pre-existing facilities. This paper will describe the underlying design principles of the integral experiment facility and the current status of SCIEL which is being constructed in KAERI (Korea Atomic Energy Research Institute). - Highlights: • Previous studies of small scale S–CO2 test loops are reviewed thoroughly. • High pressure ratio S–CO2 experiment facility was designed and constructed. • The S–CO2 compressor operation stability was checked. • Preliminary data were obtained

  15. Stochastic optimized life cycle models for risk mitigation in power system applications

    International Nuclear Information System (INIS)

    This ork shows the relevance of stochastic optimization in complex power system applications. It was proven that usual deterministic mean value models not only predict inaccurate results but are also most often on the risky side. The change in the market effects all kind of evaluation processes (e.g. fuel type and technology but especially financial engineering evaluations) in the endeavor of a strict risk mitigation comparison. But not only IPPs also traditional Utilities dash for risk/return optimized investment opportunities. In this study I developed a 2-phase model which can support a decision-maker in finding optimal solutions on investment and profitability. It has to be stated, that in this study no objective function will be optimized in an algorithmically way. On the one hand focus is laid on finding optimal solutions out of different choices (highest return at lowest possible risk); on the other hand the endeavor was to provide a decision makers with a better assessment of the likelihood of outcomes on investment considerations. The first (deterministic) phase computes in a Total Cost of Ownership (TCO) approach (Life cycle Calculation; DCF method). Most of the causal relations (day of operation, escalation of personal expanses, inflation, depreciation period, etc.) are defined within this phase. The second (stochastic) phase is a total new way in optimizing risk/return relations. With the some decision theory mathematics an expected value of stochastic solutions can be calculated. Furthermore probability function have to be defined out of historical data. The model not only supports profitability analysis (including regress and sensitivity analysis) but also supports a decision-maker in a decision process. Emphasis was laid on risk-return analysis, which can give the decision-maker first hand informations of the type of risk return problem (risk concave, averse or linear). Five important parameters were chosen which have the characteristics of typical

  16. Status of the CNES-CEA joint program on space nuclear Brayton systems

    International Nuclear Information System (INIS)

    A Cooperative program between the French Centre National d'Etudes Spatiales (CNES) and the Commissariat a l'Engergie Atomique (CEA) was initiated in 1983, to investigate the possible development of 20 to 200 kWe space nuclear power systems to be launched by the next version of the European launcher, Ariane V. After completion in 1986 of preliminary conceptual studies of a reference 200 kWe turboelectric power system, an additional 3 year study phase was decided, with the double objective of assessing the potential advantage of nuclear power systems versus solar photovoltaic or dynamic systems in the 20 kWe power range, and comparing various reactor candidate technologies and systems options for 20 kWe space nuclear power systems, likely to meet the projected energy needs of future European space missions. The results of this study are discussed by the authors

  17. A life cycle assessment scheme for environmental load estimation of power generation systems with NETS evaluation method

    International Nuclear Information System (INIS)

    This research is to analyze the environmental load on three types--natural, fossil-fuel, and nuclear power generation systems in lifecycle from the cradle to the grave. This study presents the numerical results on net energy, resources consumption and emissions of various electricity generation systems, using a whole-fuel-chain approach. For the assessment, the authors evaluated these systems using NETS (Numerical Environment Total Standard) evaluation method that is proposed here. This method describes impact on the environment in which the values change in them according to the maximum sufferable value. The NETS value is calculated from the total summation of respective environmental indices on whole processes in life cycle. As the result, a list of estimations using NETS values in power generation systems for input resources and output emissions is created as points of reference for further development and refinement to much more eco-power generation systems

  18. Power conversion cycles study for He-cooled reactor concepts for DEMO

    International Nuclear Information System (INIS)

    The study of different power conversion cycles have been performed in the framework of the DEMO scoping studies. The latter studies have the aim of providing technical information focused on the selection of DEMO parameters. The purpose of the study of conversion cycles has been the investigation of '' advanced cycles '' in order to get an improvement on the thermodynamic efficiency. Starting from the '' near term '' He-cooled blanket concepts (named, HCLL and HCPB), developed within the Power Plant Conceptual Studies (PPCS)and currently considered for DEMO, conversion cycles based on a standard Rankine cycle were shown to yield net efficiencies (net power/fusion power) of approximately 35 %. Two main features limit the efficiency of these cycles. Firstly, the heat sources in the reactor: the blanket provides the main source, over 80 % of the total thermal power. However, the blanket only produces moderate coolant temperatures with a range of 300-500 oC. The remaining thermal power, less than 20%, is deposited in the divertor as high-grade heat with a more respectable coolant temperature range of 540-717 oC. Secondly, the low inlet temperature of blanket coolant limits the possibilities to achieve efficient heat exchange with the power conversion cycle. The parameters of HCLL model AB (He-cooled divertor) have been used for the analysis of the following cycles: · Supercritical steam Rankine cycle: different configurations such as superheat cycle, reheat cycle, etc. have been studied. · Supercritical CO2 indirect Brayton cycle: the recompression cycle yields the best thermal efficiency for the Brayton cycle options. A discussion on the results considering different parameters of the cycle will be presented in the paper. · Separate cycles ('' dual cycle ''): in order to make an optimum use of the divertor high-grade heat source, independent cycles for the blanket and divertor have been considered. A comparison of the gross and net efficiencies obtained from these

  19. Economic system optimization of air-cooled organic Rankine cycles powered by low-temperature geothermal heat sources

    International Nuclear Information System (INIS)

    In this paper, an economic system optimization of an air-cooled organic Rankine cycle, powered by geothermal heat, is performed. The goal is to find the configuration of the ORC (organic Rankine cycle) which gives the highest possible net present value for the project. The cycle parameters, heat exchanger geometry and air-cooled condenser geometry are optimized together. The developed method is applied to a case study, based on a Belgian geothermal project, after which the most important parameters are varied. It is shown that the air-cooled condenser is a crucial component from both a thermodynamic and economic point of view. The discount rate, electricity price, brine inlet temperature and annual electricity price evolution have a strong influence on the configuration and efficiency of the ORC and on the economics of the project. - Highlights: • System optimization of organic Rankine cycles powered by low-temperature geothermal heat. • Models of shell-and-tube heat exchangers, air-cooled condensers and axial turbines are included. • Maximization of the net present value. • Combined optimization of cycle, configuration of heat exchangers and air-cooled condensers

  20. Investigations on an advanced power system based on a high temperature polymer electrolyte membrane fuel cell and an organic Rankine cycle for heating and power production

    International Nuclear Information System (INIS)

    Energy systems based on fuel cells technology can have a strategic role in the range of small-size power generation for the sustainable energy development. In order to enhance their performance, it is possible to recover the “waste heat” from the fuel cells, for producing or thermal power (cogeneration systems) or further electric power by means of a bottoming power cycle (combined systems). In this work an advanced system based on the integration between a HT-PEMFC (high temperature polymer electrolyte membrane fuel cell) power unit and an ORC (organic Rankine cycle) plant, has been proposed and analysed as suitable energy power plant for supplying electric and thermal energies to a stand-alone residential utility. The system can operate both as cogeneration system, in which the electric and thermal loads are satisfied by the HT-PEMFC power unit and as electric generation system, in which the low temperature heat recovered from the fuel cells is used as energy source in the ORC plant for increasing the electric power production. A numerical model, able to characterize the behavior and to predict the performance of the HT-PEMFC/ORC system under different working conditions, has been developed by using the AspenPlus™ code. - Highlights: • The advanced plant can operate both as CHP system and as electric generation system. • The performance prediction of the integrated system is carried out by numerical modeling. • ORC thermodynamic optimization is carried out by a sensitivity analysis. • Thermal coupling between the HT-PEMC system and the ORC plant is analyzed. • Results are very promising in the field of the distributed generation

  1. Heat pipe radiators for solar dynamic space power system heat rejection

    Science.gov (United States)

    Gustafson, Eric; Carlson, Albert

    1987-01-01

    The paper presents the results of a concept development study of heat rejection systems for Space Station solar dynamic power systems. The thermal performance and weights of each of the heat rejection subsystems have been addressed in detail, and critical technologies which require development tests and evaluation for successful demonstration were assessed and identified. Baseline and several alternate heat rejection system configurations and optimum designs were developed for both Brayton and Rankine cycles. The thermal performance, mass properties, assembly requirements, reliability, maintenance requirements, and life cycle costs were determined for each of the system configurations. Trade studies were performed on each configuration with respect to the heat pipe wall thickness and the amount of redundancy to determine the effects on system reliability, maintenance requirements, and life cycle costs. An optimum design was then selected for each configuration.

  2. Zero CO2 emission SOLRGT power system

    International Nuclear Information System (INIS)

    A novel hybrid power system with zero CO2 emission (ZE-SOLRGT) has been proposed and analyzed in this paper. It consists of a high temperature Brayton-like topping cycle and a high pressure-ratio Rankine-like bottoming cycle, integrated with methane-steam reforming, solar heat-assisted steam generation and CO2 capture and compression. Water is selected to be the working fluid. Solar heat input enhances the steam generation and power output, and reduces fossil fuel consumption. Besides CO2 capture with oxy-fuel combustion and cascade recuperation of turbine exhaust heat, the system is featured with indirect upgrading of low-mid temperature solar heat and cascade release of fossil fuel chemical exergy, which is described by the energy level concept. With nearly 100% CO2 capture, the system attains a net energy efficiency of 50.7% (including consideration of the energy needed for oxygen separation). The cost of generated electricity and the payback period of ZE-SOLRGT are found to be $0.056/kWh and 11.3 years, respectively. The system integration accomplishes the complementary utilization of fossil fuel and solar heat, and attains their high efficiency conversion into electricity. -- Highlights: ► A novel hybrid power system ZE-SOLRGT has been proposed and analyzed. ► The system integrates power generation with methane-steam reforming, solar heat driven steam generation and CO2 capture. ► The system is featured with indirect upgrading of solar heat and cascade release of fossil fuel chemical exergy. ► The system thermodynamic and economic performances have been investigated.

  3. Combined cycle power plant Skopje

    International Nuclear Information System (INIS)

    Regarding the new directions in constructing combined cycle power plants, in this work an idea of such plant in Skopje with power of 190 MW has been elaborated. This plant will be constructed on the site of the existing TPP 'Energetika', AD ESM. The rates of efficiency for different condition of operation has been estimated. (Author)

  4. ABB Combustion Engineering coal gasification systems for combined cycle power generation

    Energy Technology Data Exchange (ETDEWEB)

    Andrus, H.E. Jr.; Mirolli, M.D.; Vroom, H.H. III [ABB Combustion Engineering Systems, Windsor, CT (United States). Gasification Product Group

    1994-12-31

    ABB Combustion Engineering have designed and supplied IGCC power projects with a variety of power plant equipment - including the heat recovery boilers and gasifier vessel in Texaco`s Cool Water IGCC demonstration plant in California; and 120 TPD gasifier at its Windsor, Connecticut site. ABB-CE is also developing an air blown IGCC technology for applications in the power industry. This two-stage, entrained-flow, air blown, slagging bottom gasification system offers design simplicity which is anticipated to achieve greater system reliability and reduced plant maintenance costs. Discussion is presented of ABB-CE`s capabilities as a supplier of engineered gasification systems for commercially available technology, such as Texaco, Shell and Krupp (Prenflo). Also discussed is the development of ABB-CE`s air blown, entrained gasification process which is awaiting demonstration. 2 refs., 7 figs., 1 tab.

  5. Performance comparison of two low-CO2 emission solar/methanol hybrid combined cycle power systems

    International Nuclear Information System (INIS)

    Highlights: • Two novel solar hybrid combined cycle systems have been proposed and analyzed. • The power systems integrate solar-driven thermo-chemical conversion and CO2 capture. • Exergy efficiency of about 55% and specific CO2 emissions of 34 g/kW h are predicted. • Systems CO2 emissions are 36.8% lower compared to a combined cycle with CO2 capture. • The fossil fuel demand is ∼30% lower with a solar share of ∼20%. - Abstract: Two novel hybrid combined cycle power systems that use solar heat and methanol, and integrate CO2 capture, are proposed and analyzed, one based on solar-driven methanol decomposition and the other on solar-driven methanol reforming. The high methanol conversion rates at relatively low temperatures offer the advantage of using the solar heat at only 200–300 °C to drive the syngas production by endothermic methanol conversions and its conversion to chemical energy. Pre-combustion decarbonization is employed to produce CO2-free fuel from the fully converted syngas, which is then burned to produce heat at the high temperature for power generation in the proposed advanced combined cycle systems. To improve efficiency, the systems’ configurations were based on the principle of cascade use of multiple heat sources of different temperatures. The thermodynamic performance of the hybrid power systems at its design point is simulated and evaluated. The results show that the hybrid systems can attain an exergy efficiency of about 55%, and specific CO2 emissions as low as 34 g/kW h. Compared to a gas/steam combined cycle with flue gas CO2 capture, the proposed solar-assisted system CO2 emissions are 36.8% lower, and a fossil fuel saving ratio of ∼30% is achievable with a solar thermal share of ∼20%. The system integration predicts high efficiency conversion of solar heat and low-energy-penalty CO2 capture, with the additional advantage that solar heat is at relatively low temperature where its collection is cheaper and simpler

  6. Assessment of energy storage concepts for use in pulsed space power systems

    International Nuclear Information System (INIS)

    Preliminary assessments have been completed for thermal energy storage in heat rejection systems as well as for regenerable electrical storage modules in systems having nuclear sources with Rankine power conversion and solar sources with Brayton and Rankine power conversion. Storage technologies considered for the regenerable modules include flywheels, batteries, fuel cells, superconducting magnets and capacitors. Both source and sink thermal storage were examined for the solar energy based systems. Benefits derived from incorporating thermal storage in the heat rejection system depend on the storage density and the radiator specific mass. The analysis shows that inclusion of a thermal store results in heat rejection system mass reductions for generation times of up to 1100 seconds. Results show that the storage system value (mass reduction) increases with decreasing total generation time. In general, the value is greatest for generation times of 600 seconds or less although mass savings are realized for generation times nearly twice as long. For a total generation time of 500 seconds, incorporating storage in a nuclear Rankine power system results in a mass reduction of 50%. System masses similar to the nuclear Rankine are obtainable for solar Rankine and Brayton cycles using regenerable electrical storage modules. However, a 100-orbit recharge time is required, when the constraint of keeping concentrator areas smaller than 1000 m2 is also imposed

  7. Life cycle assessment(Lca) of the power generation system for the establishment of environmental management system in Korea

    International Nuclear Information System (INIS)

    The development of electricity technology from the environmental aspect has become the key factor for competitiveness, i.e., environmental friendliness is one of the most important considerations for technology development. Under the monopolised electric industry of the past, there was little motivation for individual companies to actually manage their company. However, because of the increasing demand for energy and the concerns for the environment, energy policies are shifting towards a sustainable development, which considers both the economics and environmental protection. According to the paradigm shift of the energy policy, it is necessary to compare two major electricity sources from the view of environmental management issues. It is effective with the common dimensionless unit concerning the various environmental categories including the radiological and non-radiological points of view, which can be realized by the new environmental impact assessment methodology such as the life cycle assessment (LCA). This study aims at a comparison of the environmental impacts of the nuclear and coal power generation systems using the LCA methodology. These results are very preliminary ones, however, this study will be helpful in making a decision on a long term electricity plan and the energy mix optimization when considering the environmental aspect in Korea and also the power generation companies could enhance their images by showing off their willingness to improve the environmental quality. (orig.)

  8. Emissions from cycling of thermal power plants in electricity systems with high penetration of wind power: Life cycle assessment for Ireland

    DEFF Research Database (Denmark)

    Turconi, Roberto; O'Dwyer, C.; Flynn, D.;

    2014-01-01

    -load electricity production shifts to a cleaner source than coal. Finally, the present study indicates that, in terms of emission reductions, the priority for Ireland is to phase out coal-based power plants. While investing in new storage capacity reduces system operating costs at high wind penetrations and limits...

  9. Use of molten inorganic salts as coolants in the nuclear power sector - salt of the Earth and light of the world

    International Nuclear Information System (INIS)

    The following topics are highlighted in this overview: Molten fluoride based heat transfer system (Hydrogen production by thermochemical processes; Extraction and processing of bituminous sands and oil shales; Brayton cycle for a more efficient power generation); Advanced high-temperature nuclear reactor; Liquid salt-cooled fast reactor; Molten salt reactor; and Thermonuclear hydrogen fusion. (P.A.)

  10. Long-lived radioactive waste minimization in nuclear power systems with closed nuclear fuel cycle

    International Nuclear Information System (INIS)

    Nowadays nuclear waste problem is not solved anywhere the world, and it is clear that satisfactory solution lays on the way of reducing of risk connected with nuclear waste. On this way in addition to final repository problem solution it is necessary to reduce total amount of nuclear waste, so that means: reducing the rates of cumulating of long-lived dangerous radionuclides; reducing as possible these radionuclides amounts by transmutation. These conditions can be satisfied in reasonable time by burning of minor actinides and, if possible, by transmutation of long-lived fission products. However we can use this strategy effectively if we will design and construct nuclear energy as a system which components are united by nuclear fuel cycle as a system-forming factor. The existing structures and approaches may become not sufficient. Therefore among the initial steps in nuclear waste problem considering must be researches and designs of possible promising structures of nuclear energy. In present paper systems of nuclear energy with nuclear fuel cycle closed by heavy metals are considered and equilibrium amounts of long-lived radioactive wastes are compared. (authors)

  11. Evaluation on the model of performance predictions for on-line monitoring system for combined-cycle power plant

    International Nuclear Information System (INIS)

    This paper presents the simulation model developed to predict design and off-design performance of an actual combined cycle power plant(S-Station in Korea), which would be running combined with on-line performance monitoring system in an on-line real-time fashion. The first step in thermal performance analysis is to build an accurate performance model of the power plant, in order to achieve this goal, GateCycle program has been employed in developing the model. This developed models predict design and off-design performance with a precision of one percent over a wide range of operating conditions so that on-line real-time performance monitoring can accurately establish both current performance and expected performance and also help the operator identify problems before they would be noticed

  12. Evaluation on the model of performance predictions for on-line monitoring system for combined-cycle power plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Si Moon [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    2002-07-01

    This paper presents the simulation model developed to predict design and off-design performance of an actual combined cycle power plant(S-Station in Korea), which would be running combined with on-line performance monitoring system in an on-line real-time fashion. The first step in thermal performance analysis is to build an accurate performance model of the power plant, in order to achieve this goal, GateCycle program has been employed in developing the model. This developed models predict design and off-design performance with a precision of one percent over a wide range of operating conditions so that on-line real-time performance monitoring can accurately establish both current performance and expected performance and also help the operator identify problems before they would be noticed.

  13. External costs of electric power generation systems. Nuclear fuel cycle in ExternE

    International Nuclear Information System (INIS)

    In ExternE, external costs on mine steps such as mining and refining of uranium, conversion, enrichment, fuel production, power generation, reprocessing, wastes treatment, transportation, and construction and subdivision were evaluated. However, even treatment of same a step is not always carried out in own country. In order to conduct a fair evaluation, every country must elucidate performances of its specified sites. And, ExternE defines some important evaluation items (priority Impact) thought to largely affect the external cost formed at every stage in each power generation system. In addition, ExternE also considers on some impact routes of radioactive materials. On calculation result of external costs on the nuclear power generation, as its methodology is common, its evaluation results are not always realistic because of use of French data using Phase II when insufficiency of data in own country, use of supposed site condition, use of different time span for evaluating effect, and so forth. (G.K.)

  14. Model predictive control system and method for integrated gasification combined cycle power generation

    Science.gov (United States)

    Kumar, Aditya; Shi, Ruijie; Kumar, Rajeeva; Dokucu, Mustafa

    2013-04-09

    Control system and method for controlling an integrated gasification combined cycle (IGCC) plant are provided. The system may include a controller coupled to a dynamic model of the plant to process a prediction of plant performance and determine a control strategy for the IGCC plant over a time horizon subject to plant constraints. The control strategy may include control functionality to meet a tracking objective and control functionality to meet an optimization objective. The control strategy may be configured to prioritize the tracking objective over the optimization objective based on a coordinate transformation, such as an orthogonal or quasi-orthogonal projection. A plurality of plant control knobs may be set in accordance with the control strategy to generate a sequence of coordinated multivariable control inputs to meet the tracking objective and the optimization objective subject to the prioritization resulting from the coordinate transformation.

  15. Evaluation of technical feasibility of closed-cycle non-equilibrium MHD power generation with direct coal firing. Final report, Task 1

    Energy Technology Data Exchange (ETDEWEB)

    1981-11-01

    Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal fired, closed cycle, magnetohydrodynamic power generation are detailed. These accomplishments relate to all system aspects of a CCMHD power generation system including coal combustion, heat transfer to the MHD working fluid, MHD power generation, heat and cesium seed recovery and overall systems analysis. Direct coal firing of the combined cycle has been under laboratory development in the form of a high slag rejection, regeneratively air cooled cyclone coal combustor concept, originated within this program. A hot bottom ceramic regenerative heat exchanger system was assembled and test fired with coal for the purposes of evaluating the catalytic effect of alumina on NO/sub x/ emission reduction and operability of the refractory dome support system. Design, procurement, fabrication and partial installation of a heat and seed recovery flow apparatus was accomplished and was based on a stream tube model of the full scale system using full scale temperatures, tube sizes, rates of temperature change and tube geometry. Systems analysis capability was substantially upgraded by the incorporation of a revised systems code, with emphasis on ease of operator interaction as well as separability of component subroutines. The updated code was used in the development of a new plant configuration, the Feedwater Cooled (FCB) Brayton Cycle, which is superior to the CCMHD/Steam cycle both in performance and cost. (WHK)

  16. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part B: Application on a Case Study

    Directory of Open Access Journals (Sweden)

    Angelo La Seta

    2016-05-01

    Full Text Available Organic Rankine cycle (ORC power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. The design process and efficiency estimation are particularly challenging due to the peculiar physical properties of the working fluid and the gas-dynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders combine small enthalpy drops with large expansion ratios. These features yield turbine designs with few highly-loaded stages in supersonic flow regimes. Part A of this two-part paper has presented the implementation and validation of the simulation tool TURAX, which provides the optimal preliminary design of single-stage axial-flow turbines. The authors have also presented a sensitivity analysis on the decision variables affecting the turbine design. Part B of this two-part paper presents the first application of a design method where the thermodynamic cycle optimization is combined with calculations of the maximum expander performance using the mean-line design tool described in part A. The high computational cost of the turbine optimization is tackled by building a model which gives the optimal preliminary design of an axial-flow turbine as a function of the cycle conditions. This allows for estimating the optimal expander performance for each operating condition of interest. The test case is the preliminary design of an organic Rankine cycle turbogenerator to increase the overall energy efficiency of an offshore platform. For an increase in expander pressure ratio from 10 to 35, the results indicate up to 10% point reduction in expander performance. This corresponds to a relative reduction in net power output of 8.3% compared to the case when the turbine efficiency is assumed to be 80%. This work also demonstrates that this approach can support the plant designer

  17. Design of a condenser-boiler for a binary mercury-organic Rankine cycle solar dynamic space power system

    Science.gov (United States)

    Cotton, Randy M.

    1987-05-01

    A theoretical design was performed for the condenser/boiler of a space-based solar dynamic power system. The base system is a binary Rankine cycle with mercury and toluene as the working fluids. System output is 75 KWe with a combined efficiency of 41.1%. Design goals were to develop the most reliable, mass efficient unit possible for delivery to a space station. The design sized the unit based on toluene properties and used a computer generated heat balance to thermodynamically match the two fluids. Molybdenum was chosen as the material due to mass effectiveness in heat transfer, strength, and resistance to mercury corrosion. The unit transferred 137.46 kilowatts of thermal power and can operate at varying mass flow rates. Effectiveness in heat transfer is 0.96 and mass performance is 0.016 kg/KWth transferred. The design depends on using only existing technologies and the results call for no new developments.

  18. Proactive pressure relief system management of life cycle and ageing in nuclear power plants

    International Nuclear Information System (INIS)

    The last major power nuclear station built in North America was built when the Altair Company introduced the first microcomputer sparking the PC frenzy. It is safe to assume that there have been a great many changes since 1977 on both accounts. As the world's aging nuclear plants continue to be challenged with maintenance and replacement issues (obsolescence), as well making improvements within their facilities, proper pressure relief system management looms as a growing concern. This problem grows more acute as new engineering best practices are promulgated across industries and regulatory standards become more rigorous with much stricter enforcements. Unlike most pieces of operating equipment in a nuclear facility, pressure relief devices demand an extra level of consideration; as they form the 'last line of defense'. Combine the on-going obsolescence issue, with today's ever increasing demands for overall plant and public safety; pressure relief safety management will require increasing 'proactive' efforts to ensure safe facilities. This paper has been written to address some global pressure relief system management issues with respect the worlds aging nuclear facilities. This paper reflects findings we have discovered while conducting engineering pressure relief system audits on various nuclear power stations. It should be noted that these finding are not atypical of similar findings in pressure relief systems in the hydrocarbon processing world. (author)

  19. Solar thermal power systems point-focusing distributed receiver /PFDR/ technology - A project description

    Science.gov (United States)

    Lucas, J. W.; Roschke, E. J.

    1978-01-01

    The goal of the Project is to support the industrial development of PFDR technology that will provide favorable life-cycle costs per unit of electrical or thermal energy produced. The technology will be made available in the early 1980s for applications project experiments. PFDR systems utilize concentrator dishes to furnish energy to their own individual receivers and power conversion subsystems. Initial effort is with steam Rankine and gas Brayton cycles. Periodic assessments will be made to confirm or change the cycles initially selected. Subsystems will be designed, fabricated and tested together in modules as appropriate. This paper describes PFDR systems briefly, outlines the project goals and organization, discusses the plans and current status of the project, and lists the benefits of PFDR technology concepts.

  20. Lunar electric power systems utilizing the SP-100 reactor coupled to dynamic conversion systems. Final report

    International Nuclear Information System (INIS)

    An integration study was performed by Rocketdyne under contract to NASA-LeRC. The study was concerned with coupling an SP-0100 reactor to either a Brayton or Stirling power conversion system. The application was for a surface power system to supply power requirements to a lunar base. A power level of 550 kWe was selected based on the NASA Space Exploration Initiative 90-day study. Reliability studies were initially performed to determine optimum power conversion redundancy. This study resulted in selecting three operating engines and one stand-by unit. Integration design studies indicated that either the Brayton or Stirling power conversion systems could be integrated with the PS-100 reactor. The Stirling system had an integration advantage because of smaller piping size and fewer components. The Stirling engine, however, is more complex and heavier than the Brayton rotating unit, which tends to off-set the Stirling integration advantage. From a performance consideration, the Brayton had a 9 percent mass advantage, and the Stirling had a 50 percent radiator advantage

  1. Design and commissioning of a TF coil power system using deep-cycle batteries for versatile experiment spherical torus (VEST)

    International Nuclear Information System (INIS)

    A toroidal field (TF) coil power system has been designed and successfully commissioned to be suitable for the research objectives of VEST (Versatile Experiment Spherical Torus) which was recently constructed at Seoul National University. The TF coil power system for VEST is fabricated using a series–parallel connection of 200 deep-cycle batteries with 100 A h capacity so as to generate flat-top TF field of 0.12 T on magnetic axis for sufficiently long time up to hundreds of milliseconds. Ten battery modules are designed to operate independently through 10 magnetic contactor (MC) switches so as to produce toroidal magnetic field with various amplitudes and waveforms. During the initial start-up experiments of VEST, the modulation capability of toroidal magnetic field is successfully verified, showing possibility of its versatile utilization on various experimental topics in the future

  2. Life cycle assessment and evaluation of energy payback time on high-concentration photovoltaic power generation system

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, A.; Hayashi, Y.; Tanaka, K.; Hirota, M.; Kato, S. [Mie Univ., Tsu, Mie (Japan). Dept. of Mechanical Engineering; Ito, M. [Tokyo Inst. of Technology, Tokyo (Japan). Integrated Research Inst.; Araki, K. [Daido Steel Co. Ltd., Nagoya (Japan). Research and Development Lab.; Hu, E.J. [Deakin Univ., Geelong, Victoria (Australia). School of Engineering and Information Technology

    2008-07-01

    Photovoltaic power generation (PV) which uses renewable solar energy is considered to be a promising technology to meet the rapidly increasing energy demands of the future. In particular, a high-concentration photovoltaic power generation system (HCPV) has the advantage of high power conversion efficiency by a small solar cell chip with the aid of a solar radiation concentration lens. This study used a life cycle assessment (LCA) scheme to evaluate the environmental load of a very large-scale PV system during its life cycle. It also estimated the energy payback time (EPT) which is usually used for energy recovery evaluation. Two hypothetical case studies in Toyohashi, Japan and Gobi dessert in China were used to determine how location and PV type affect the environmental load and EPT of an HCPV. The study involved the use of a multi-crystalline silicon photovoltaic power generation system (mc-Si PV). This flat plate type PV system is usually placed on roofs and is a competitor for HCPV. The study showed that for a 100 MW PV system, the total impacts of the HCPV installed in Toyohashi was larger than that of the HCPV installed in Gobi desert by 5 per cent, without consideration of recycling stage. The EPT of the HCPV installed in Gobi desert was shorter than the EPT of the HCPV installed in Toyohashi by 0.64 year. The results indicated that it is preferable to install a PV system in the Gobi desert. A comparison of the HCPV and mc-Si PV showed that the ratio of the total impacts of the mc-Si PV to that of the HCPV was 0.34 without consideration of recycling stage. The EPT of the HCPV was longer than the EPT of the mc-Si PV by 0.27 year. The amount of global solar radiation contributing to the amount of power generation of the mc-Si PV was larger than the amount of direct solar radiation contributing to the amount of power generation of the HCPV by about 188 kWh/(m{sup 2} per year) in the Gobi desert. It was concluded that the using the mc-Si PV in the Gobi desert

  3. Dynamic simulation of a reverse Brayton refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Peng, N.; Xiong, L. Y.; Dong, B.; Liu, L. Q. [State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, CAS, Beijing, 100190 (China); Lei, L. L.; Tang, J. C. [State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, CAS, Beijing, 100190 China and Graduate University of Chinese Academy of Sciences, Beijing, 100190 (China)

    2014-01-29

    A test refrigerator based on the modified Reverse Brayton cycle has been developed in the Chinese Academy of Sciences recently. To study the behaviors of this test refrigerator, a dynamic simulation has been carried out. The numerical model comprises the typical components of the test refrigerator: compressor, valves, heat exchangers, expander and heater. This simulator is based on the oriented-object approach and each component is represented by a set of differential and algebraic equations. The control system of the test refrigerator is also simulated, which can be used to optimize the control strategies. This paper describes all the models and shows the simulation results. Comparisons between simulation results and experimental data are also presented. Experimental validation on the test refrigerator gives satisfactory results.

  4. Dynamic simulation of a reverse Brayton refrigerator

    International Nuclear Information System (INIS)

    A test refrigerator based on the modified Reverse Brayton cycle has been developed in the Chinese Academy of Sciences recently. To study the behaviors of this test refrigerator, a dynamic simulation has been carried out. The numerical model comprises the typical components of the test refrigerator: compressor, valves, heat exchangers, expander and heater. This simulator is based on the oriented-object approach and each component is represented by a set of differential and algebraic equations. The control system of the test refrigerator is also simulated, which can be used to optimize the control strategies. This paper describes all the models and shows the simulation results. Comparisons between simulation results and experimental data are also presented. Experimental validation on the test refrigerator gives satisfactory results

  5. Life cycle assessment and evaluation of energy payback time on high-concentration photovoltaic power generation system

    International Nuclear Information System (INIS)

    In this study, the environmental load of photovoltaic power generation system (PV) during its life cycle and energy payback time (EPT) are evaluated by LCA scheme. Two hypothetical case studies in Toyohashi, Japan and Gobi dessert in China have been carried out to investigate the influence of installation location and PV type on environmental load and EPT. The environmental load and EPT of a high-concentration photovoltaic power generation system (hcpV) and a multi-crystalline silicon photovoltaic power generation system (mc-Si PV) are studied. The study shows for a PV of 100 MW size, the total impacts of the hcpV installed in Toyohashi is larger than that of the hcpV installed in Gobi desert by 5% without consideration of recycling stage. The EPT of the hcpV assumed to be installed in Gobi desert is shorter than EPT of the hcpV assumed to be installed in Toyohashi by 0.64 year. From these results, the superiority to install PV in Gobi desert is certificated. Comparing with hcpV and mc-Si PV, the ratio of the total impacts of mc-Si PV to that of hcpV is 0.34 without consideration of recycling stage. The EPT of hcpV is longer than EPT of mc-Si PV by 0.27 year. The amount of global solar radiation contributing to the amount of power generation of mc-Si PV is larger than the amount of direct solar radiation contributing to the amount of power generation of hcpV by about 188 kW h/(m2 year) in Gobi desert. Consequently, it appears that using mc-Si PV in Gobi desert is the best option.

  6. Life cycle assessment and evaluation of energy payback time on high-concentration photovoltaic power generation system

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, A.; Hayashi, Y.; Tanaka, K.; Hirota, M.; Kato, S. [Division of Mechanical Engineering, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507 (Japan); Ito, M. [Integrated Research Institute, Tokyo Institute of Technology, I6-25 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Araki, K. [R and D Lab, Daido Steel Co., Ltd., 2-30 Daido-cho, Minami-ku, Nagoya 457-8545 (Japan); Hu, E.J. [School of Mechanical Engineering, The University of Adelaide, North Terrace, Adelaide, SA 5005 (Australia)

    2010-09-15

    In this study, the environmental load of photovoltaic power generation system (PV) during its life cycle and energy payback time (EPT) are evaluated by LCA scheme. Two hypothetical case studies in Toyohashi, Japan and Gobi dessert in China have been carried out to investigate the influence of installation location and PV type on environmental load and EPT. The environmental load and EPT of a high-concentration photovoltaic power generation system (hcpV) and a multi-crystalline silicon photovoltaic power generation system (mc-Si PV) are studied. The study shows for a PV of 100 MW size, the total impacts of the hcpV installed in Toyohashi is larger than that of the hcpV installed in Gobi desert by 5% without consideration of recycling stage. The EPT of the hcpV assumed to be installed in Gobi desert is shorter than EPT of the hcpV assumed to be installed in Toyohashi by 0.64 year. From these results, the superiority to install PV in Gobi desert is certificated. Comparing with hcpV and mc-Si PV, the ratio of the total impacts of mc-Si PV to that of hcpV is 0.34 without consideration of recycling stage. The EPT of hcpV is longer than EPT of mc-Si PV by 0.27 year. The amount of global solar radiation contributing to the amount of power generation of mc-Si PV is larger than the amount of direct solar radiation contributing to the amount of power generation of hcpV by about 188 kW h/(m{sup 2} year) in Gobi desert. Consequently, it appears that using mc-Si PV in Gobi desert is the best option. (author)

  7. Energetic analysis of a novel vehicle power and cooling/heating cogeneration energy system using cascade cycles

    International Nuclear Information System (INIS)

    This study proposes and investigates a novel VCES (Vehicle power and cooling/heating Cogeneration Energy System), including a topping vehicle engine subsystem, and a bottoming waste-heat recovery subsystem which uses the zeotropic working fluid. The various grade exhaust and coolant waste-heat of the topping subsystem are cascade recovered by the bottoming subsystem, and slide-temperature thermal match in waste heat recovery heat exchangers and the condenser is considered also, obtaining power output and cooling/heating capacity. Based on the experimental data from an actual vehicle's energy demands and its waste-heat characteristics, the proposed VCES (vehicle cogeneration energy system) model is built and verified. Using ammonia-water as working fluid of the bottoming subsystem, integrated thermodynamic performances of the VCES are discussed through introducing three variables: an ambient temperature, the vehicle's velocity and the number of seated occupants. The influence of above three variables on the proposed VCES′ overall thermodynamic performance is analyzed by comparing it to a conventional VCES, and suitable operation conditions are recommended under cooling and heating conditions. - Highlights: • A novel vehicle cogeneration energy system is proposed. • Slide-temperature thermal match at two levels are considered. • Integration of the topping vehicle engine and bottoming waste heat recovery cycle is designed. • The cogeneration system model is built and verified based on experimental data. • Energy-saving potential of the proposed system is investigated

  8. Evaluation of technical feasibility of closed-cycle non-equilibrium MHD power generation with direct coal firing. Final report, Task I

    Energy Technology Data Exchange (ETDEWEB)

    1981-11-01

    Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal-fired, closed-cycle MHD power generation are reported. This volume contains the following appendices: (A) user's manual for 2-dimensional MHD generator code (2DEM); (B) performance estimates for a nominal 30 MW argon segmented heater; (C) the feedwater cooled Brayton cycle; (D) application of CCMHD in an industrial cogeneration environment; (E) preliminary design for shell and tube primary heat exchanger; and (F) plant efficiency as a function of output power for open and closed cycle MHD power plants. (WHK)

  9. Electric power generation. Thermal power generating systems

    International Nuclear Information System (INIS)

    This is a manuscript for a lecture contents: 1) Steam power and fundamentals of the steam power process, 3) conventional, nuclear and other steam generation processes, 4) cooling systems for steam power plants, 5) gas turbine power plants and combined-cycle power plants, 6) cogeneration, 7) development of thermal power plants and environmental effects. (GL)

  10. Octave-spanning OPCPA system delivering CEP-stable few-cycle pulses and 22 W of average power at 1 MHz repetition rate.

    Science.gov (United States)

    Rothhardt, Jan; Demmler, Stefan; Hädrich, Steffen; Limpert, Jens; Tünnermann, Andreas

    2012-05-01

    We report on an OPCPA system delivering CEP-stable pulses with a pulse duration of only 1.7 optical cycles at 880 nm wavelength. This pulse duration is achieved by the generation, optical parametric amplification and compression of a full optical octave of bandwidth. The system is pumped by a high average power Yb-fiber laser system, which allows for operation of the OPCPA at up to 1 MHz repetition rate and 22 W of average output power. Further scaling towards single-cycle pulses, higher energy and output power is discussed. PMID:22565712

  11. Low-Concentration Solar-Power Systems Based on Organic Rankine Cycles for Distributed-Scale Applications: Overview and Further Developments

    OpenAIRE

    Markides, Christos N.

    2015-01-01

    This paper is concerned with the emergence and development of low-to-medium-grade thermal-energy-conversion systems for distributed power generation based on thermodynamic vapor-phase heat-engine cycles undergone by organic working fluids, namely organic Rankine cycles (ORCs). ORC power systems are, to some extent, a relatively established and mature technology that is well-suited to converting low/medium-grade heat (at temperatures up to ~300–400°C) to useful work, at an output power scale f...

  12. 11-th International conference Nuclear power safety and nuclear education - 2009. Abstracts. Part 1. Session: Safety of nuclear technology; Innovative nuclear systems and fuel cycle; Nuclear knowledge management

    International Nuclear Information System (INIS)

    The book includes abstracts of the 11-th International conference Nuclear power safety and nuclear education - 2009 (29 Sep - 2 Oct, 2009, Obninsk). Problems of safety of nuclear technology are discussed, innovative nuclear systems and fuel cycles are treated. Abstracts on professional education for nuclear power and industry are presented. Nuclear knowledge management are discussed

  13. Analysis and performance assessment of a multigenerational system powered by Organic Rankine Cycle for a net zero energy house

    International Nuclear Information System (INIS)

    This paper develops a new Organic Rankine Cycle (ORC) based multigenerational system to meet the demands of a net zero energy building and assesses such a system for an application to a net zero energy house in Lebanon. Solar energy is the prime source for the integrated system to achieve multigeneration to supply electricity, fresh and hot water, seasonal heating and cooling. The study starts by optimizing the power system with and without grid connection. Then, a comprehensive thermodynamic analysis through energy and exergy, and a parametric study to assess the sensitivity and improvements of the overall system are conducted. Furthermore, exergoeconomic analysis and a follow-up optimization study for optimizing the total system cost to the overall system efficiency using genetic algorithm to obtain the optimal design or a set of optimal designs (Pareto Front), are carried out. The present results show that the optimum solar energy system for a total connected load to the house of 90 kWh/day using a combination of ORC, batteries, convertor has a total net present cost of US $52,505.00 (based on the prices in 2013) with a renewable energy fraction of 1. Moreover, the optimization for the same connected load with ORC, batteries and converter configuration with grid connection results in a total net present cost of $50,868.00 (2013) with a renewable energy fraction of 0.992 with 169 kg/yr of CO2 emissions. In addition, exergoeconomic analysis of the overall system yields a cost of $117,700.00 (2013), and the multi-objective optimization provides the overall exergetic efficiency by 14% at a total system cost increase of $10,500.00 (2013). - Highlights: • To develop a new Organic Rankine Cycle (ORC) based multigenerational system to meet the demands of a net zero energy building. • To perform a comprehensive thermodynamic analysis through energy and exergy approaches. • To apply an exergoeconomic model for exergy-based cost accounting. • To undertake

  14. ABB combustion engineering coal gasification system for combined cycle power generation

    Energy Technology Data Exchange (ETDEWEB)

    Andrus, H.E.; Mirolli, M.D.; Vroom, H.H. (ABB Combustion Engineering (United States))

    1993-01-01

    ABB Combustion Engineering is one of the main suppliers of equipment to IGCC projects. It supplied the heat recovery boilers and gasifier vessel at Texaco's Coal Water IGCC demonstration plant in California. Complete plants can be constructed, from coal grinding and preparation; through char removal and recycle; to hot gas cleanup. The low BTU gases produced can be burnt in a standard gas turbine. ABB-CE is developing an air blown IGCC technology for the power industry, comprising a two-stage, entrained flow, air blown, slagging bottom gasification process. The air blown model offers a simplicity that should increase reliability and reduce maintenance costs. 2 refs., 7 figs.

  15. Maximisation of Combined Cycle Power Plant Efficiency

    Directory of Open Access Journals (Sweden)

    Janusz Kotowicz

    2015-12-01

    Full Text Available The paper presents concepts for increasing the efficiency of a modern combined cycle power plant. Improvement of gas turbine performance indicators as well as recovering heat from the air cooling the gas turbine’s flow system enable reaching gross electrical efficiencies of around 65%. Analyses for a wide range of compressor pressure ratios were performed. Operating characteristics were developed for the analysed combined cycle plant, for different types of open air cooling arrangements of the gas turbine’s expander: convective, transpiration and film.

  16. Nuclear-Powered GPS Spacecraft Design Study

    Energy Technology Data Exchange (ETDEWEB)

    Raab, Bernard

    1977-05-01

    This is the final report of a study to investigate the potential benefits of a nuclear (radioisotope) - powered satellite for advanced phases of the Global Positioning System (GPS) program. The critical parameters were: power to user; mean mission duration; orbital predictability; thermal control of on-board frequency standards; and vulnerability. The reference design approach is described, and input data are given for two power systems that are under development: an organic Rankine system and a Brayton cycle system. Reference design details are provided and structural design and analysis are discussed, as well as thermal design and analysis. A higher altitude version is also considered.

  17. Power extraction from aeroelastic limit cycle oscillations

    Science.gov (United States)

    Dunnmon, J. A.; Stanton, S. C.; Mann, B. P.; Dowell, E. H.

    2011-11-01

    Nonlinear limit cycle oscillations of an aeroelastic energy harvester are exploited for enhanced piezoelectric power generation from aerodynamic flows. Specifically, a flexible beam with piezoelectric laminates is excited by a uniform axial flow field in a manner analogous to a flapping flag such that the system delivers power to an electrical impedance load. Fluid-structure interaction is modeled by augmenting a system of nonlinear equations for an electroelastic beam with a discretized vortex-lattice potential flow model. Experimental results from a prototype aeroelastic energy harvester are also presented. Root mean square electrical power on the order of 2.5 mW was delivered below the flutter boundary of the test apparatus at a comparatively low wind speed of 27 m/s and a chord normalized limit cycle amplitude of 0.33. Moreover, subcritical limit cycles with chord normalized amplitudes of up to 0.46 were observed. Calculations indicate that the system tested here was able to access over 17% of the flow energy to which it was exposed. Methods for designing aeroelastic energy harvesters by exploiting nonlinear aeroelastic phenomena and potential improvements to existing relevant aerodynamic models are also discussed.

  18. Power system

    Science.gov (United States)

    Hickam, Christopher Dale

    2008-03-18

    A power system includes a prime mover, a transmission, and a fluid coupler having a selectively engageable lockup clutch. The fluid coupler may be drivingly connected between the prime mover and the transmission. Additionally, the power system may include a motor/generator drivingly connected to at least one of the prime mover and the transmission. The power-system may also include power-system controls configured to execute a control method. The control method may include selecting one of a plurality of modes of operation of the power system. Additionally, the control method may include controlling the operating state of the lockup clutch dependent upon the mode of operation selected. The control method may also include controlling the operating state of the motor/generator dependent upon the mode of operation selected.

  19. Advanced latent heat of fusion thermal energy storage for solar power systems

    Science.gov (United States)

    Phillips, W. M.; Stearns, J. W.

    1985-01-01

    The use of solar thermal power systems coupled with thermal energy storage (TES) is being studied for both terrestrial and space applications. In the case of terrestrial applications, it was found that one or two hours of TES could shift the insolation peak (solar noon) to coincide with user peak loads. The use of a phase change material (PCM) is attractive because of the higher energy storage density which can be achieved. However, the use of PCM has also certain disadvantages which must be addressed. Proof of concept testing was undertaken to evaluate corrosive effects and thermal ratcheting effects in a slurry system. It is concluded that the considered alkali metal/alkali salt slurry approach to TES appears to be very viable, taking into account an elimination of thermal ratcheting in storage systems and the reduction of corrosive effects. The approach appears to be useful for an employment involving temperatures applicable to Brayton or Stirling cycles.

  20. Analyzing the possibility of constructing the air heating system for an integrated solid fuel gasification combined-cycle power plant

    Science.gov (United States)

    Mikula, V. A.; Ryzhkov, A. F.; Val'tsev, N. V.

    2015-11-01

    Combined-cycle power plants operating on solid fuel have presently been implemented only in demonstration projects. One of possible ways for improving such plants consists in making a shift to hybrid process circuits of integrated gasification combined-cycle plants with external firing of solid fuel. A high-temperature air heater serving to heat compressed air is a key element of the hybrid process circuit. The article describes application of a high-temperature recuperative metal air heater in the process circuit of an integrated gasification combined-cycle power plant (IGCC). The available experience with high-temperature air heating is considered, and possible air heater layout arrangements are analyzed along with domestically produced heat-resistant grades of steel suitable for manufacturing such air heater. An alternative (with respect to the traditional one) design is proposed, according to which solid fuel is fired in a noncooled furnace extension, followed by mixing the combustion products with recirculation gases, after which the mixture is fed to a convective air heater. The use of this design makes it possible to achieve considerably smaller capital outlays and operating costs. The data obtained from thermal and aerodynamic calculations of the high-temperature air heater with a thermal capacity of 258 MW for heating air to a temperature of up to 800°C for being used in the hybrid process circuit of a combined-cycle power plant are presented.

  1. Exergoeconomic performance optimization of an endoreversible intercooled regenerative Brayton combined heat and power plant coupled to variable-temperature heat reservoirs

    Directory of Open Access Journals (Sweden)

    Bo Yang, Lingen Chen, Fengrui Sun

    2012-01-01

    Full Text Available An endoreversible intercooled regenerative Brayton combined heat and power (CHP plant model coupled to variable-temperature heat reservoirs is established. The exergoeconomic performance of the CHP plant is investigated using finite time thermodynamics. The analytical formulae about dimensionless profit rate and exergy efficiency of the CHP plant with the heat resistance losses in the hot-, cold- and consumer-side heat exchangers, the intercooler and the regenerator are deduced. By taking the maximum profit rate as the objective, the heat conductance allocation among the five heat exchangers and the choice of intercooling pressure ratio are optimized by numerical examples, the characteristic of the optimal dimensionless profit rate versus corresponding exergy efficiency is investigated. When the optimization is performed further with respect to the total pressure ratio, a double-maximum profit rate is obtained. The effects of the design parameters on the double-maximum dimensionless profit rate and corresponding exergy efficiency, optimal total pressure ratio and optimal intercooling pressure ratio are analyzed in detail, and it is found that there exist an optimal consumer-side temperature and an optimal thermal capacitance rate matching between the working fluid and the heat reservoir, respectively, corresponding to a thrice-maximum dimensionless profit rate.

  2. Exergoeconomic performance optimization of an endoreversible intercooled regenerative Brayton combined heat and power plant coupled to variable-temperature heat reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Bo; Chen, Lingen; Sun, Fengrui [College of Naval Architecture and Power, Naval University of Engineering, Wuhan 430033 (China)

    2012-07-01

    An endoreversible intercooled regenerative Brayton combined heat and power (CHP) plant model coupled to variable-temperature heat reservoirs is established. The exergoeconomic performance of the CHP plant is investigated using finite time thermodynamics. The analytical formulae about dimensionless profit rate and exergy efficiency of the CHP plant with the heat resistance losses in the hot-, cold- and consumer-side heat exchangers, the intercooler and the regenerator are deduced. By taking the maximum profit rate as the objective, the heat conductance allocation among the five heat exchangers and the choice of intercooling pressure ratio are optimized by numerical examples, the characteristic of the optimal dimensionless profit rate versus corresponding exergy efficiency is investigated. When the optimization is performed further with respect to the total pressure ratio, a double-maximum profit rate is obtained. The effects of the design parameters on the double-maximum dimensionless profit rate and corresponding exergy efficiency, optimal total pressure ratio and optimal intercooling pressure ratio are analyzed in detail, and it is found that there exist an optimal consumer-side temperature and an optimal thermal capacitance rate matching between the working fluid and the heat reservoir, respectively, corresponding to a thrice-maximum dimensionless profit rate.

  3. Power, efficiency, entropy-generation rate and ecological optimization for a class of generalized irreversible universal heat-engine cycles

    International Nuclear Information System (INIS)

    The optimal performance for a class of generalized irreversible universal steady-flow heat-engine cycle models, consisting of two heating branches, two cooling branches and two adiabatic branches, and with losses due to heat-resistance, heat leaks and internal irreversibility was analyzed using finite-time thermodynamics. The analytical formulae for power, efficiency, entropy-generation rate and an ecological criterion of the irreversible heat-engine cycle are derived. Moreover, analysis and optimization of the model were carried out in order to investigate the effect of the cycle process on the performance of the cycles. The results obtained include the performance characteristics of Diesel, Otto, Brayton, Atkinson, Dual and Miller cycles with the losses of heat-resistance, heat leak and internal irreversibility

  4. Investigating factors affecting the efficiency of gas turbine power cycle

    OpenAIRE

    Ghaderi, R.; M. Damircheli

    2014-01-01

    Today, the use of gas turbines in power generation cycles has been growing. Small size, easy installation, high power-to-mass ratio and the ability to load and unload the cycle quickly are the advantages of such systems. Low efficiency is considered as one of the major disadvantages of such power plants. Thus providing a way to increase cycle efficiency can be very effective in making the cycle more efficient and thus saving fuel consumed in such systems. In this paper the thermal efficiency ...

  5. Metal corrosion in a supercritical carbon dioxide - liquid sodium power cycle.

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Robert Charles; Conboy, Thomas M.

    2012-02-01

    A liquid sodium cooled fast reactor coupled to a supercritical carbon dioxide Brayton power cycle is a promising combination for the next generation nuclear power production process. For optimum efficiency, a microchannel heat exchanger, constructed by diffusion bonding, can be used for heat transfer from the liquid sodium reactor coolant to the supercritical carbon dioxide. In this work, we have reviewed the literature on corrosion of metals in liquid sodium and carbon dioxide. The main conclusions are (1) pure, dry CO{sub 2} is virtually inert but can be highly corrosive in the presence of even ppm concentrations of water, (2) carburization and decarburization are very significant mechanism for corrosion in liquid sodium especially at high temperature and the mechanism is not well understood, and (3) very little information could be located on corrosion of diffusion bonded metals. Significantly more research is needed in all of these areas.

  6. Sensible heat receiver for solar dynamic space power system

    Science.gov (United States)

    Perez-Davis, Marla E.; Gaier, James R.; Petrefski, Chris

    1991-01-01

    A sensible heat receiver is considered which uses a vapor grown carbon fiber-carbon (VGCF/C) composite as the thermal storage medium and which was designed for a 7-kW Brayton engine. This heat receiver stores the required energy to power the system during eclipse in the VGCF/C composite. The heat receiver thermal analysis was conducted through the Systems Improved Numerical Differencing Analyzer and Fluid Integrator (SINDA) software package. The sensible heat receiver compares well with other latent and advanced sensible heat receivers analyzed in other studies, while avoiding the problems associated with latent heat storage salts and liquid metal heat pipes. The concept also satisfies the design requirements for a 7-kW Brayton engine system. The weight and size of the system can be optimized by changes in geometry and technology advances for this new material.

  7. Parabolic Trough Organic Rankine Cycle Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Canada, S.; Cohen, G.; Cable, R.; Brosseau, D.; Price, H.

    2005-01-01

    Arizona Public Service (APS) is required to generate a portion of its electricity from solar resources in order to satisfy its obligation under the Arizona Environmental Portfolio Standard (EPS). In recent years, APS has installed and operates over 4.5 MWe of fixed, tracking, and concentrating photovoltaic systems to help meet the solar portion of this obligation and to develop an understanding of which solar technologies provide the best cost and performance to meet utility needs. During FY04, APS began construction of a 1-MWe parabolic trough concentrating solar power plant. This plant represents the first parabolic trough plant to begin construction since 1991. The plant will also be the first commercial deployment of the Solargenix parabolic trough collector technology developed under contract to the National Renewable Energy Laboratory (NREL). The plant will use an organic Rankine cycle (ORC) power plant, provided by Ormat. The ORC power plant is much simpler than a conventional steam Rankine cycle power plant and allows unattended operation of the facility.

  8. Liquid-Flooded Ericsson Power Cycle

    OpenAIRE

    James, Nelson A.; Braun, James E.; Groll, Eckhard A.; Horton, W. Travis

    2014-01-01

    In this paper, the use of liquid flooding is examined to create a high efficiency Ericsson Power Cycle. The introduction of significant amounts of liquid into the compression and expansion processes of a gas leads to quasi-isothermal behavior approximating that of an Ericsson cycle. A thermodynamic model is presented and various working fluid pairs are examined under operating conditions suitable for solar thermal power generation. The Liquid-Flooded Ericsson Cycle (LFEC) can be manufactured ...

  9. Carbon Cycling with Nuclear Power

    Science.gov (United States)

    Lackner, Klaus S.

    2011-11-01

    Liquid hydrocarbon fuels like gasoline, diesel or jet fuel are the most efficient ways of delivering energy to the transportation sector, in particular cars, ships and airplanes. Unfortunately, their use nearly unavoidably leads to the emission of carbon dioxide into the atmosphere. Unless an equivalent amount is removed from the air, the carbon dioxide will accumulate and significantly contribute to the man-made greenhouse effect. If fuels are made from biomass, the capture of carbon dioxide is a natural part of the cycle. Here, we discuss technical options for capturing carbon dioxide at much faster rates. We outline the basic concepts, discuss how such capture technologies could be made affordable and show how they could be integrated into a larger system approach. In the short term, the likely source of the hydrocarbon fuels is oil or gas; in the longer term, technologies that can provide energy to remove oxygen from carbon dioxide and water molecules and combine the remaining components into liquid fuels make it possible to recycle carbon between fuels and carbon dioxide in an entirely abiotic process. Here we focus on renewable and nuclear energy options for producing liquid fuels and show how air capture combined with fuel synthesis could be more economic than a transition to electric cars or hydrogen-fueled cars.

  10. Solar dynamic heat rejection technology. Task 1: System concept development

    Science.gov (United States)

    Gustafson, Eric; Carlson, Albert W.

    1987-01-01

    The results are presented of a concept development study of heat rejection systems for Space Station solar dynamic power systems. The heat rejection concepts are based on recent developments in high thermal transport capacity heat pipe radiators. The thermal performance and weights of each of the heat rejection subsystems is addressed in detail, and critical technologies which require development tests and evaluation for successful demonstration are assessed and identified. Baseline and several alternate heat rejection system configurations and optimum designs are developed for both Brayton and Rankine cycles. The thermal performance, mass properties, assembly requirements, reliability, maintenance requirements and life cycle cost are determined for each configuration. A specific design was then selected for each configuration which represents an optimum design for that configuration. The final recommendations of heat rejection system configuration for either the Brayton or Rankine cycles depend on the priorities established for the evaluation criteria.

  11. Technical feasibility of the electrode ionization process for the makeup water treatment system of the thermal cycle of the CAREM-25 nuclear power plant

    International Nuclear Information System (INIS)

    In thermal cycles of PWRs nuclear power plants with once-through steam generators as the CAREM-25, makeup water of very high purity is required to minimizing the induction of corrosion phenomena, fundamentally in the steam generators and other thermal cycle components. The makeup water treatment systems include several stages, of which the demineralization is the purification stage. The required makeup water purity is obtained in this stage. Historically, ultrapure water systems were based completely on ion exchange technology. Now, the electrode ionization process (EDI) has replaced the ion exchange technology used traditionally in the demineralization stage. Continuous demineralization in an EDI stack consists of three coupled processes: ion exchange, continuous ion removal by transport through the ion exchange resin and membranes into the concentrate stream, continuous regeneration by hydrogen and hydroxyl ions derived from the water splitting reaction and driven by the applied direct current. EDI process allows to obtain ultrapure water, with practically no use of chemical reagents and with technologies of continuous process. The objective of this work is the analysis of the electrode ionization process (EDI) for its implementation in the makeup water treatment system of the thermal cycle of the CAREM-25 nuclear power plant. The obtained results allow to assure the technical feasibility of implementation of the electrode ionization process, EDI, in the makeup water treatment system of the thermal cycle of this Argentinean nuclear power plant. (author)

  12. Hybrid combined cycle power plant

    International Nuclear Information System (INIS)

    In case of re-powering the existing pressurised water nuclear power plants by the proposed HCCPP solution, we can increase the electricity output and efficiency significantly. If we convert a traditional nuclear power plant unit to a HCCPP solution, we can achieve a 3.2-5.5 times increase in electricity output and the achievable gross efficiency falls between 46.8-52% and above, depending on the applied solution. These figures emphasise that we should rethink our power plant technologies and we have to explore a great variety of HCCPP solutions. This may give a new direction in the development of nuclear reactors and power plants as well.(author)

  13. Performance analyses of oxy-fuel power generation systems including CO2 capture: comparison of two cycles using different recirculation fluids

    International Nuclear Information System (INIS)

    With increasing concerns on global warming, reduction of CO2 emission has become a hot issue and studies of CO2 capture and storage (CCS) technology in power plant applications are in progress. Oxy-fuel combustion is one of the several available technologies that intend to capture CO2. Since the combustion gas consists mainly of CO2 and H2O in oxy-fuel combustion systems, it is easy to separate CO2 from the flue gas using a simple mechanical method instead of complex chemical processes. There have been suggested a couple of power cycles using different recirculation fluids for combustion dilution purpose. This study aimed to investigate the influence of CO2 capture on the performance of two promising oxy-fuel combustion power cycles adopting H2O and CO2 as the recirculation fluid. Optimal integration between the carbon capture process and the power cycle was examined and the influences of carbon capture on the entire system performance were compared for the two cycles

  14. Optimization of Biomass-Fuelled Combined Cooling, Heating and Power (CCHP) Systems Integrated with Subcritical or Transcritical Organic Rankine Cycles (ORCs)

    OpenAIRE

    Daniel Maraver; Sylvain Quoilin; Javier Royo

    2014-01-01

    This work is focused on the thermodynamic optimization of Organic Rankine Cycles (ORCs), coupled with absorption or adsorption cooling units, for combined cooling heating and power (CCHP) generation from biomass combustion. Results were obtained by modelling with the main aim of providing optimization guidelines for the operating conditions of these types of systems, specifically the subcritical or transcritical ORC, when integrated in a CCHP system to supply typical heating and cooling deman...

  15. Optimization of a Brayton cryocooler for ZBO liquid hydrogen storage in space

    Science.gov (United States)

    Deserranno, D.; Zagarola, M.; Li, X.; Mustafi, S.

    2014-11-01

    NASA is evaluating and developing technology for long-term storage of cryogenic propellant in space. A key technology is a cryogenic refrigerator which intercepts heat loads to the storage tank, resulting in a reduced- or zero-boil-off condition. Turbo-Brayton cryocoolers are particularly well suited for cryogen storage applications because the technology scales well to high capacities and low temperatures. In addition, the continuous-flow nature of the cycle allows direct cooling of the cryogen storage tank without mass and power penalties associated with a cryogenic heat transport system. To quantify the benefits and mature the cryocooler technology, Creare Inc. performed a design study and technology demonstration effort for NASA on a 20 W, 20 K cryocooler for liquid hydrogen storage. During the design study, we optimized these key components: three centrifugal compressors, a modular high-capacity plate-fin recuperator, and a single-stage turboalternator. The optimization of the compressors and turboalternator were supported by component testing. The optimized cryocooler has an overall flight mass of 88 kg and a specific power of 61 W/W. The coefficient of performance of the cryocooler is 23% of the Carnot cycle. This is significantly better performance than any 20 K space cryocooler existing or under development.

  16. Release and sorption of alkali metals in coal fired combined cycle power systems; Freisetzung und Einbindung von Alkalimetallverbindungen in kohlebefeuerten Kombikraftwerken

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Michael

    2009-07-01

    Coal fired combined cycle power systems will be a sufficient way to increase the efficiency of coal combustion. However, combined cycle power systems require a reliable hot gas cleanup. Especially alkali metals, such as sodium and potassium, can lead to hot corrosion of the gas turbine blading if they condensate as sulphates. The actual work deals with the release and sorption of alkali metals in coal fired combined cycle power systems. The influence of coal composition, temperature and pressure on the release of alkali species in coal combustion was investigated and the relevant release mechanisms identified. Alumosilicate sorbents have been found that reduce the alkali concentration in the hot flue gas of the Circulating Pressurized Fluidized Bed Combustion 2{sup nd} Generation (CPFBC 2{sup nd} Gen.) at 750 C to values sufficient for use in a gas turbine. Accordingly, alumosilicate sorbents working at 1400 C have been found for the Pressurized Pulverized Coal Combustion (PPCC). The sorption mechanisms have been identified. Thermodynamic calculations were performed to upscale the results of the laboratory experiments to conditions prevailing in power systems. According to these calculations, there is no risk of hot corrosion in both processes. Furthermore, thermodynamic calculations were performed to investigate the behaviour of alkali metals in an IGCC with integrated hot gas cleanup and H{sub 2} membrane for CO{sub 2} sequestration. (orig.)

  17. Fuel cycles for electric power generation

    International Nuclear Information System (INIS)

    An illustrative data base is presented of material quantities and environmental effluents in the fuel cycles for alternative technologies of thermally generated power. The entire fuel cycle for each of ten alternative technologies is outlined for a representative power plant generating 1000 Mw of electrical power. The required utilization of material resources and the fuel cycle material quantities are indicated on a flow sheet for each technology. The technologies considered include: light-water nuclear reactors, coal, residual fuel oil, natural gas, geothermal steam, breeder fission reactors, solar energy, and thermonuclear fusion

  18. Prospects of power conversion technology of direct-cycle helium gas turbine for MHTGR

    International Nuclear Information System (INIS)

    The modular high temperature gas cooled reactor (MHTGR) is a modern passively safe reactor. The reactor and helium gas turbine may be combined for high efficiency's power conversion, because MHTGR has high outlet temperature up to 950 degree C. Two different schemes are planed separately by USA and South Africa. the helium gas turbine methodologies adopted by them are mainly based on the developed heavy duty industrial and aviation gas turbine technology. The author introduces the differences of two technologies and some design issues in the design and manufacture. Moreover, the author conclude that directly coupling a closed Brayton cycle gas turbine concept to the passively safe MHTGR is the developing direction of MHTGR due to its efficiency which is much higher than that of using steam turbine

  19. Specification of life cycle assessment in nuclear power plants

    International Nuclear Information System (INIS)

    Life Cycle Assessment is an environmental management tool for assessing the environmental impacts of a product of a process. life cycle assessment involves the evaluation of environmental impacts through all stages of life cycle of a product or process. In other words life cycle assessment has a cradle to graveapproach. Some results of life cycle assessment consist of pollution prevention, energy efficient system, material conservation, economic system and sustainable development. All power generation technologies affect the environment in one way or another. The main environmental impact does not always occur during operation of power plant. The life cycle assessment of nuclear power has entailed studying the entire fuel cycle from mine to deep repository, as well as the construction, operation and demolition of the power station. Nuclear power plays an important role in electricity production for several countries. even though the use of nuclear power remains controversial. But due to the shortage of fossil fuel energy resources many countries have started to try more alternation to their sources of energy production. A life cycle assessment could detect all environmental impacts of nuclear power from extracting resources, building facilities and transporting material through the final conversion to useful energy services

  20. Life cycle assessment of greenhouse gas emissions, water and land use for concentrated solar power plants with different energy backup systems

    International Nuclear Information System (INIS)

    Concentrated solar power (CSP) is unique among intermittent renewable energy options because for the past four years, utility-scale plants have been using an energy storage technology that could allow a CSP plant to operate as a baseload renewable energy generator in the future. No study to-date has directly compared the environmental implications of this technology with more conventional CSP backup energy options. This study compares the life cycle greenhouse gas (GHG) emissions, water consumption, and direct, onsite land use associated with one MW h of electricity production from CSP plants with wet and dry cooling and with three energy backup systems: (1) minimal backup (MB), (2) molten salt thermal energy storage (TES), and (3) a natural gas-fired heat transfer fluid heater (NG). Plants with NG had 4–9 times more life cycle GHG emissions than plants with TES. Plants with TES generally had twice as many life cycle GHG emissions as the MB plants. Dry cooling reduced life cycle water consumption by 71–78% compared to wet cooling. Plants with larger backup capacities had greater life cycle water consumption than plants with smaller backup capacities, and plants with NG had lower direct, onsite life cycle land use than plants with MB or TES. - highlights: • We assess life cycle environmental effects of concentrated solar power (CSP). • We compare CSP with three energy backup technologies and two cooling technologies. • We selected solar field area to minimize energy cost for plants with minimal backup and salt storage. • Life cycle greenhouse gas emissions were 4–9 times lower with thermal energy storage than with fossil fuel backup. • Dry cooling reduced life cycle water use by 71–78% compared to wet cooling

  1. Feasibility Study of Mixture Gas Coolant Based HTGR Concept using Conventional Gas Turbine Power Conversion Systems

    International Nuclear Information System (INIS)

    This paper proposes a couple of new ideas to tackle those issues and evaluates their feasibility. The details are presented in the following sections. A Very High Temperature Reactor (VHTR) is one of the most promising Gen-IV reactor concepts due to its inherent safety, high efficiency, and various possibilities of high temperature application. Nevertheless, there are still some technical issues for the near-term commercialization (i. e. high temperature materials, closed gas Brayton cycle, low power density, etc)

  2. Assessment of solar options for small power systems applications. Volume II. Identification and characterization of concepts for analysis

    Energy Technology Data Exchange (ETDEWEB)

    Laity, W.W.; Aase, D.T.; Apley, W.J.; Bird, S.P.; Drost, M.K.; Williams, T.A.

    1980-06-01

    The primary purpose of this study is to provide DOE with an independent, objective assessment of the principal solar thermal conversion concepts that have the potential for achieving commercial success as small electric power sytems in the 1- to 10-MWe range. Seven generic types of collectors, together with associated subsystems for electric power generation, were considered in this study. The collectors can be classified into three categories: (1) two-axis tracking (with compound curvature reflecting surfaces); (2) one-axis tracking (with single-curvature reflecting surfaces); and (3) nontracking (with low-concentration reflecting surfaces). These collectors can be combined with energy transport, energy storage, and power conversion subsystems in a wide variety of ways to formulate conceptual systems for electric power generation. In this study, attention was restricted to configurations that are potentially suitable for development as small power systems (1 to 10 MWe) in the long term (1990 to 2000), with initial commercialization by the mid-1980s. Cogeneration and total energy systems were beyond the scope of this study. All seven types of collectors were analyzed in conceptual system configurations with Rankine-cycle engines. Because they can operate at particularly high concentration ratios, two of the collectors (the Point Focus Central Receiver and the Point Focus Distributed Receiver) were also analyzed with Brayton-cycle engines. In addition, the latter of the two was analyzed with Stirling-cycle engines. With these engine options, 10 conceptual systems were formulated for analysis. Results are presented in detail. (WHK)

  3. Supercritical CO2 Brayton power cycles for DEMO (demonstration power plant) fusion reactor based on dual coolant lithium lead blanket

    OpenAIRE

    Linares, José Ignacio; Cantizano González, Alexis; Moratilla, Beatriz Y.; Martin Palacios, Victor; Batet Miracle, Lluís

    2016-01-01

    The purpose of this website is to provide information about fusion and fusion research, particularly the research activities related to EUROfusion. Neither EUROfusion, the EUROfusion Research Units, the European Commission, nor anyone acting on their behalf, is responsible for any damage resulting from the use of information contained on this website. Unless otherwise explicitly stated, all information, text and electronic images contained on this website are the intellectual property of ...

  4. ESCORT: A Pratt & Whitney nuclear thermal propulsion and power system for manned mars missions

    Science.gov (United States)

    Feller, Gerald J.; Joyner, Russell

    1999-01-01

    The purpose of this paper is to describe the conceptual design of an upgrade to the Pratt & Whitney ESCORT nuclear thermal rocket engine. The ESCORT is a bimodal engine capable of supporting a wide range of vehicle propulsive and electrical power requirements. The ESCORT engine is powered by a fast-spectrum beryllium-reflected CERMET-fueled nuclear reactor. In propulsive mode, the reactor is used to heat hot hydrogen to approximately 2700 K which is expanded through a converging/diverging nozzle to generate thrust. Heat pickup in the nozzle and the radial beryllium reflectors is used to drive the turbomachinery in the ESCORT expander cycle. In electrical mode, the reactor is used to heat a mixture of helium and xenon to drive a closed-loop Brayton cycle in order to generate electrical energy. This closed loop system has the additional function of a decay heat removal system after the propulsive mode operation is discontinued. The original ESCORT design was capable of delivering 4448.2 N (1000 lbf) of thrust at a vacuum impulse level of approximately 900 s. Design Reference Mission requirements (DRM) from NASA Johnson Space Center and NASA Lewis Research Center studies in 1997 and 1998 have detailed upgraded requirements for potential manned Mars missions. The current NASA DRM requires a nuclear thermal propulsion system capable of delivering total mission requirements of 200170 N (45000 lbf) thrust and 50 kWe of spacecraft electrical power. This is met assuming three engines capable of each delivering 66723 N (15000 lbf) of vacuum thrust and 25 kWe of electrical power. The individual engine requirements were developed assuming three out of three engine reliability for propulsion and two out of three engine reliability for spacecraft electrical power. The approximate target vacuum impulse is 925 s. The Pratt & Whitney ESCORT concept was upgraded to meet these requirements. The hexagonal prismatic fuel elements were modified to address the uprated power requirements

  5. CO2 mitigation in advanced power cycles

    OpenAIRE

    Wolf, Jens

    2004-01-01

    This thesis encompasses CO2 mitigation using three different processes: i) natural gas-fired combined cycle with chemical looping combustion (CLC), ii) trigeneration of electrical power, hydrogen and district heating with extended CLC, iii) steam-based gasification of biomass integrated in an advanced power cycle. In CLC, a solid oxygen carrier circulates between two fluidised-bed reactors and transports oxygen from the combustion air to the fuel; thus, the fuel is not mixed with air and an i...

  6. Low-Concentration Solar-Power Systems based on Organic Rankine Cycles for Distributed-Scale Applications:Overview and Further Developments

    Directory of Open Access Journals (Sweden)

    Christos N. Markides

    2015-12-01

    Full Text Available This paper is concerned with the emergence and development of low- to medium-grade thermal-energy conversion systems for distributed power generation based on thermodynamic vapour-phase heat-engine cycles undergone by organic working-fluids, namely organic Rankine cycles (ORCs. ORC power systems are, to some extent, a relatively established and mature technology that is well-suited to converting low-/medium-grade heat (at temperatures up to ~ 300 – 400 °C to useful work, at an output power scale from a few kW to 10s of MW. Thermal efficiencies in excess of 25% are achievable at higher temperatures and larger scales, and efforts are currently in progress to improve the overall economic viability, and thus uptake, of ORC power systems by focusing on advanced architectures, working-fluid selection, heat exchangers and expansion machines. Solar-power systems based on ORC technology have a significant potential to be used for distributed power generation, by converting thermal energy from simple and low-cost non-concentrated or low-concentration collectors to mechanical, hydraulic or electrical energy. Current fields of use include mainly geothermal and biomass/biogas, as well as the recovery and conversion of waste heat, leading to improved energy efficiency, primary energy (i.e. fuel use and emission minimization, yet the technology is highly transferable to solar power generation as an affordable alternative to small- to medium-scale photovoltaic (PV systems. Solar-ORC systems offer naturally the advantages of providing a simultaneous thermal-energy output for hot water provision and/or space heating, and the particularly interesting possibility of relatively straightforward on-site (thermal energy storage. Key performance characteristics are presented, and important heat transfer effects that act to limit performance are identified as noteworthy directions of future research for the further development of this technology.

  7. Assessment of solar options for small power systems applications. Volume IV. Comparative ranking of concepts

    Energy Technology Data Exchange (ETDEWEB)

    Currie, J.W.; Jannol, M.

    1980-07-01

    A comparative analysis of solar thermal conversion concepts that are potentially suitable for development as small electric power systems (1 to 10 MWe) is presented. Cogeneration and total energy systems were beyond the scope of this study. Seven generic type of collectors, together with associated subsystems for electric power generation, were considered. The collectors can be classified into three categories: (1) two-axis tracking (with compound-curvature reflecting surfaces); (2) one-axis tracking (with single-curvature reflecting surfaces; and (3) nontracking (with low-concentration reflecting surfaces). All seven collectors were analyzed in conceptual system configurations with Rankine-cycle engines. In addition, two of the collectors (the Point Focus Central Receiver and the Point Focus Distributed Receiver) were analyzed with Brayton-cycle engines, and the latter of the two also was analyzed with Stirling-cycle engines. With these engine options, 10 systems were formulated for analysis. This is the fourth volume of a five-volume report on the work performed to analyze the alternative concepts, and the results obtained. Included in this volume are descriptions of the methodology used with, and concept ranks obtained from, potential users and R and D fund allocators.

  8. Closed power cycles thermodynamic fundamentals and applications

    CERN Document Server

    Invernizzi, Costante Mario

    2013-01-01

    With the growing attention to the exploitation of renewable energies and heat recovery from industrial processes, the traditional steam and gas cycles are showing themselves often inadequate. The inadequacy is due to the great assortment of the required sizes power and of the large kind of heat sources. Closed Power Cycles: Thermodynamic Fundamentals and Applications offers an organized discussion about the strong interaction between working fluids, the thermodynamic behavior of the cycle using them and the technological design aspects of the machines. A precise treatment of thermal engines op

  9. Energy efficiency analysis and impact evaluation of the application of thermoelectric power cycle to today's CHP systems

    International Nuclear Information System (INIS)

    High efficiency thermoelectric generators (TEG) can recover waste heat from both industrial and private sectors. Thus, the development and deployment of TEG may represent one of the main drives for technological change and fuel substitution. This paper will present an analysis of system efficiency related to the integration of TEG into thermal energy systems, especially Combined Heat and Power production (CHP). Representative implementations of installing TEG in CHP plants to utilize waste heat, wherein electricity can be generated in situ as a by-product, will be described to show advantageous configurations for combustion systems. The feasible deployment of TEG in various CHP plants will be examined in terms of heat source temperature range, influences on CHP power specification and thermal environment, as well as potential benefits. The overall conversion efficiency improvements and economic benefits, together with the environmental impact of this deployment, will then be estimated. By using the Danish thermal energy system as a paradigm, this paper will consider the TEG application to district heating systems and power plants through the EnergyPLAN model, which has been created to design suitable energy strategies for the integration of electricity production into the overall energy system.

  10. Performance analysis of a large-scale helium Brayton cryo-refrigerator with static gas bearing turboexpander

    International Nuclear Information System (INIS)

    Highlights: • A 2 kW at 20.0 K helium Brayton cryo-refrigerator is built in China. • A series of tests have been systematically conducted to investigate the performance of the cryo-refrigerator. • Maximum heat conductance proportion (90.7%) appears in the heat exchangers of cold box rather than those of heat reservoirs. • A model of helium Brayton cryo-refrigerator/cycle is presented according to finite-time thermodynamics. - Abstract: Large-scale helium cryo-refrigerator is widely used in superconducting systems, nuclear fusion engineering, and scientific researches, etc., however, its energy efficiency is quite low. First, a 2 kW at 20.0 K helium Brayton cryo-refrigerator is built, and a series of tests have been systematically conducted to investigate the performance of the cryo-refrigerator. It is found that maximum heat conductance proportion (90.7%) appears in the heat exchangers of cold box rather than those of heat reservoirs, which is the main characteristic of the helium Brayton cryo-refrigerator/cycle different from the air Brayton refrigerator/cycle. Other three characteristics also lie in the configuration of refrigerant helium bypass, internal purifier and non-linearity of specific heat of helium. Second, a model of helium Brayton cryo-refrigerator/cycle is presented according to finite-time thermodynamics. The assumption named internal purification temperature depth (PTD) is introduced, and the heat capacity rate of whole cycle is divided into three different regions in accordance with the PTD: room temperature region, upper internal purification temperature region and lower one. Analytical expressions of cooling capacity and COP are obtained, and we found that the expressions are piecewise functions. Further, comparison between the model and the experimental results for cooling capacity of the helium cryo-refrigerator shows that error is less than 7.6%. The PTD not only helps to achieve the analytical formulae and indicates the working

  11. Investigating factors affecting the efficiency of gas turbine power cycle

    Directory of Open Access Journals (Sweden)

    R. Ghaderi

    2014-05-01

    Full Text Available Today, the use of gas turbines in power generation cycles has been growing. Small size, easy installation, high power-to-mass ratio and the ability to load and unload the cycle quickly are the advantages of such systems. Low efficiency is considered as one of the major disadvantages of such power plants. Thus providing a way to increase cycle efficiency can be very effective in making the cycle more efficient and thus saving fuel consumed in such systems. In this paper the thermal efficiency of the cycle is introduced through describing the mechanism of gas turbine in power generation cycle. Then we will examine the factors affecting the efficiency of the cycle and finally practical solutions such as increasing the inlet temperature, recovery, internal cooling of the compressor and heat recovery for increasing efficiency will be explained. Evaluating the polytropic efficiency of cycles shows that increasing the inlet gas temperature has little effect on turbine efficiency and is limited at high levels of ηpoly. Water or steam injection into the gas turbines will not only lead to increased efficiency of the cycle, but also increases the flexibility of the turbine, too.

  12. Preliminary Study of the Supercritical CO2 Hybrid Cycle for the HTGR Application

    International Nuclear Information System (INIS)

    This study was conducted to explore the potential of Supercritical Carbon Dioxide (S-CO2) Brayton cycle for the HTGR application. The S-CO2 cycle is being considered as a PCS due to its high thermal efficiency, simplicity, compactness and so on. Generally, the S-CO2 Brayton cycle is characterized as a highly recuperated cycle which means that to achieve high thermal efficiency, the cycle requires a highly effective recuperator. Argonne National Laboratory (ANL) showed that direct application of the standard S-CO2 recompressing Brayton cycle to the HTGR or the Very High Temperature Reactor (VHTR) is difficult to achieve high thermal efficiency due to the mismatch of the temperature difference between the temperature drop of helium as the primary reactor coolant and the temperature rise of CO2 as the PCS coolant through an Intermediate Heat Exchanger (IHX). Therefore, our research team suggests a novel S-CO2 cycle configuration, the S-CO2 Brayton and Rankine hybrid cycle, to solve this limitation. This S-CO2 hybrid concept is utilizing the waste heat of the S-CO2 Brayton cycle as heat input to the S-CO2 Rankine cycle. Dividing the thermal capacity of the heat source in to the Brayton cycle part and Rankine cycle part of the S-CO2 hybrid cycle appropriately, the temperature difference at the IHX could be reduced, therefore the net system performance and operating range can be improved. In this study, the ANL research is reviewed by the in-house cycle analysis codes developed by the Korea Advanced Institute of Science and Technology (KAIST) research team. And the S-CO2 Brayton and Rankine hybrid cycle is studied as a PCS for the VHTR condition which was utilized by ANL research team; it was assumed that the core outlet temperature to be 850 .deg. C and the core inlet temperature of 400 .deg. C

  13. Energy efficiency analysis and impact evaluation of the application of thermoelectric power cycle to today's CHP systems

    DEFF Research Database (Denmark)

    Chen, Min; Lund, Henrik; Rosendahl, Lasse;

    2010-01-01

    High efficiency thermoelectric generators (TEG) can recover waste heat from both industrial and private sectors. Thus, the development and deployment of TEG may represent one of the main drives for technological change and fuel substitution. This paper will present an analysis of system efficiency...... related to the integration of TEG into thermal energy systems, especially Combined Heat and Power production (CHP). Representative implementations of installing TEG in CHP plants to utilize waste heat, wherein electricity can be generated in situ as a by-product, will be described to show advantageous...... configurations for combustion systems. The feasible deployment of TEG in various CHP plants will be examined in terms of heat source temperature range, influences on CHP power specification and thermal environment, as well as potential benefits. The overall conversion efficiency improvements and economic...

  14. High cycle thermal fatigue: benchmark at a Te junction piping system of the nuclear power plant Phenix

    International Nuclear Information System (INIS)

    This paper presents the studies of the benchmark concerning a high cycle thermal fatigue problem. This benchmark is based on an industrial case, a Te junction piping system of the french FBR Phenix. The main objectives were the comparison of the different methods used by the participants and the analysis of the damage evaluation methods capacity compared to the observed phenomena. This study took place in an international framework with the United Kingdom, Italy, Japan, Korea, Russia, India and France. (A.L.B.)

  15. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A

    DEFF Research Database (Denmark)

    Meroni, Andrea; La Seta, Angelo; Andreasen, Jesper Graa;

    2016-01-01

    Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary...... turbine design model, the details of the validation and a sensitivity analysis on the main parameters, in order to minimize the number of decision variables in the subsequent turbine design optimization. Part B analyzes the application of the combined turbine and cycle designs on a selected case study...

  16. Efficient cycles for carbon capture CLC power plants based on thermally balanced redox reactors

    KAUST Repository

    Iloeje, Chukwunwike

    2015-10-01

    © 2015 Elsevier Ltd. The rotary reactor differs from most alternative chemical looping combustion (CLC) reactor designs because it maintains near-thermal equilibrium between the two stages of the redox process by thermally coupling channels undergoing oxidation and reduction. An earlier study showed that this thermal coupling between the oxidation and reduction reactors increases the efficiency by up to 2% points when implemented in a regenerative Brayton cycle. The present study extends this analysis to alternative CLC cycles with the objective of identifying optimal configurations and design tradeoffs. Results show that the increased efficiency from reactor thermal coupling applies only to cycles that are capable of exploiting the increased availability in the reduction reactor exhaust. Thus, in addition to the regenerative cycle, the combined CLC cycle and the combined-regenerative CLC cycle are suitable for integration with the rotary reactor. Parametric studies are used to compare the sensitivity of the different cycle efficiencies to parameters like pressure ratio, turbine inlet temperature, carrier-gas fraction and purge steam generation. One of the key conclusions from this analysis is that while the optimal efficiency for regenerative CLC cycle was the highest of the three (56% at 3. bars, 1200. °C), the combined-regenerative cycle offers a trade-off that combines a reasonably high efficiency (about 54% at 12. bars, 1200. °C) with much lower gas volumetric flow rate and consequently, smaller reactor size. Unlike the other two cycles, the optimal compressor pressure ratio for the regenerative cycle is weakly dependent on the design turbine inlet temperature. For the regenerative and combined regenerative cycles, steam production in the regenerator below 2× fuel flow rate improves exhaust recovery and consequently, the overall system efficiency. Also, given that the fuel side regenerator flow is unbalanced, it is more efficient to generate steam from the

  17. Exfoliation Propensity of Oxide Scale in Heat Exchangers Used for Supercritical CO2 Power Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, Adrian S [ORNL; Shingledecker, John P. [Electric Power Research Institute (EPRI); Kung, Steve [Electric Power Research Institute (EPRI); Wright, Ian G. [WrightHT, Inc.; Nash, Jim [Brayton Energy, LLC, Hampton, NH

    2016-01-01

    Supercritical CO2 (sCO2) Brayton cycle systems offer the possibility of improved efficiency in future fossil energy power generation plants operating at temperatures of 650 C and above. As there are few data on the oxidation/corrosion behavior of structural alloys in sCO2 at these temperatures, modeling to predict the propensity for oxide exfoliation is not well developed, thus hindering materials selection for these novel cycles. The ultimate goal of this effort is to provide needed data on scale exfoliation behavior in sCO2 for confident alloy selection. To date, a model developed by ORNL and EPRI for the exfoliation of oxide scales formed on boiler tubes in high-temperature, high-pressure steam has proven useful for managing exfoliation in conventional steam plants. A major input provided by the model is the ability to predict the likelihood of scale failure and loss based on understanding of the evolution of the oxide morphologies and the conditions that result in susceptibility to exfoliation. This paper describes initial steps taken to extend the existing model for exfoliation of steam-side oxide scales to sCO2 conditions. The main differences between high-temperature, high-pressure steam and sCO2 that impact the model involve (i) significant geometrical differences in the heat exchangers, ranging from standard pressurized tubes seen typically in steam-producing boilers to designs for sCO2 that employ variously-curved thin walls to create shaped flow paths for extended heat transfer area and small channel cross-sections to promote thermal convection and support pressure loads; (ii) changed operating characteristics with sCO2 due to the differences in physical and thermal properties compared to steam; and (iii) possible modification of the scale morphologies, hence properties that influence exfoliation behavior, due to reaction with carbon species from sCO2. The numerical simulations conducted were based on an assumed sCO2 operating schedule and several

  18. Advanced power cycling test for power module with on-line on-state VCE measurement

    DEFF Research Database (Denmark)

    Choi, Ui-min; Trintis, Ionut; Blaabjerg, Frede; Jørgensen, Søren; Svarre, Morten Liengaard

    Recent research has made an effort to improve the reliability of power electronic systems to comply with more stringent constraints on cost, safety, predicted lifetime and availability in many applications. For this, studies about failure mechanisms of power electronic components and lifetime...... estimation of power semiconductor devices and capacitors have been done. Accelerated power cycling test is one of the common tests to assess the power device module and develop the lifetime model considering the physics of failure. In this paper, a new advanced power cycling test setup is proposed for power...

  19. GT-MHR helium gas turbine power conversion system design and development

    International Nuclear Information System (INIS)

    It is projected that shortly after the year 2000 combustion gas turbines will become the dominant prime-mover for electrical power generation in the US. These plants will operate with fossil fuels (i.e., natural gas and gasified coal) and have efficiencies of 60%. As environmental concerns intensify there will be a quest for ''greener'' power generation technologies, and this can be realized with a gas turbine coupled to a nonfossil heat source, namely an advanced nuclear reactor. The gas turbine modular helium reactor (GT-MHR) is a power plant with a meltdown-proof reactor and a high efficiency prime-mover based on proven technologies. A reactor core with a power rating of 550 MW(t) was selected in order to provide margin on design limits, however a design goal was established to achieve a growth potential to 600 MW(t). This module rating makes it ideally suited to the needs of both the industrialized and developing nations. The power conversion system is based on an intercooled and recuperated closed Brayton cycle with a projected efficiency of over 47% for the initial unit that could be in utility service in the first decade of the next century. With technology advancements, particularly higher values of reactor outlet temperature, the potential exists for an efficiency increase to over 60%. This paper focuses on the design and development of the helium gas turbine power conversion system

  20. Use of the available energy in the re-gasification process of liquefied natural gas by coupling combined heat and power cycles

    Energy Technology Data Exchange (ETDEWEB)

    Sgarbi, P.V.; Schmeda Lopez, D.R.; Indrusiak, M.L.S.; Schneider, P. Smith [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Dept. of Mechanical Engineering], Emails: guetuso@gmail.com, diego.schmeda@ufrgs.br, sperbindrusiak@via-rs.net, pss@mecanica.ufrgs.br

    2009-07-01

    This work evaluates the possibilities of taking advantage of the heat transferred in the re-gasification process of liquid natural gas (LNG). It is proposed the coupling of a Brayton-Rankine combined heat and power plant (CHP) to a LNG re-gasification plant in order to use the heat involved in this process as cold source for the CHP plant. For comparison, the same CHP is simulated exchanging heat with a reference environment. An analysis is performed assuming that the amount of natural gas fed to the Brayton sub-cycle combustion chamber is equal for both cases. The CHP coupled to the re-gasification plant present a net power generation of 22.7 MW and the efficiency is 45.5%. It represents a gain of 2.98 MW in the power generation and 15% in the cycle efficiency, when compared to the reference cycle. The exergetic efficiency with this proposal is 49.3%, which is 9% higher than the reference cycle. (author)

  1. Assessment of the integration of a He-cooled divertor system in the power conversion system for the dual-coolant blanket concept (TW2-TRP-PPCS12D8)

    Energy Technology Data Exchange (ETDEWEB)

    Norajitra, P.; Kruessmann, R.; Malang, S.; Reimann, G.

    2002-12-01

    Application of a helium-cooled divertor together with the dual-coolant blanket concept is considered favourable for achieving a high thermal efficiency of the power plant due to its relatively high coolant outlet temperature. A new FZK He-cooled modular divertor concept with integrated pin arrays (HEMP) is introduced. Its main features and function are described in detail. The result of the thermalhydraulic analysis shows that the HEMP divertor concept has the potential of resisting, a heat flow density of at least 10-15 MW/m{sup 2} at a reachable heat transfer coefficient of approx. 60 kW/m{sup 2}K and a reasonable pumping power. Integration of this divertor concept into the power conversion system using a closed Brayton gas turbine system with three-stage compression leads to a net efficiency of the blanket/divertor cycle of about 43%. (orig.)

  2. Thermally regenerative hydrogen/oxygen fuel cell power cycles

    Science.gov (United States)

    Morehouse, J. H.

    1986-01-01

    Two innovative thermodynamic power cycles are analytically examined for future engineering feasibility. The power cycles use a hydrogen-oxygen fuel cell for electrical energy production and use the thermal dissociation of water for regeneration of the hydrogen and oxygen. The TDS (thermal dissociation system) uses a thermal energy input at over 2000 K to thermally dissociate the water. The other cycle, the HTE (high temperature electrolyzer) system, dissociates the water using an electrolyzer operating at high temperature (1300 K) which receives its electrical energy from the fuel cell. The primary advantages of these cycles is that they are basically a no moving parts system, thus having the potential for long life and high reliability, and they have the potential for high thermal efficiency. Both cycles are shown to be classical heat engines with ideal efficiency close to Carnot cycle efficiency. The feasibility of constructing actual cycles is investigated by examining process irreversibilities and device efficiencies for the two types of cycles. The results show that while the processes and devices of the 2000 K TDS exceed current technology limits, the high temperature electrolyzer system appears to be a state-of-the-art technology development. The requirements for very high electrolyzer and fuel cell efficiencies are seen as determining the feasbility of the HTE system, and these high efficiency devices are currently being developed. It is concluded that a proof-of-concept HTE system experiment can and should be conducted.

  3. Integration of A Solid Oxide Fuel Cell into A 10 MW Gas Turbine Power Plant

    Directory of Open Access Journals (Sweden)

    Denver F. Cheddie

    2010-04-01

    Full Text Available Power generation using gas turbine power plants operating on the Brayton cycle suffers from low efficiencies. In this work, a solid oxide fuel cell (SOFC is proposed for integration into a 10 MW gas turbine power plant, operating at 30% efficiency. The SOFC system utilizes four heat exchangers for heat recovery from both the turbine outlet and the fuel cell outlet to ensure a sufficiently high SOFC temperature. The power output of the hybrid plant is 37 MW at 66.2% efficiency. A thermo-economic model predicts a payback period of less than four years, based on future projected SOFC cost estimates.

  4. Development of a 77K Reverse-Brayton Cryocooler with Multiple Coldheads Project

    Data.gov (United States)

    National Aeronautics and Space Administration — RTI will design and optimize an 80 W, 77K cryocooler based on the reverse turbo Brayton cycle (RTBC) with four identical coldheads for distributed cooling. Based on...

  5. Design and Implementation of A PV Powered Tri-Cycle

    Directory of Open Access Journals (Sweden)

    Soumya Das

    2016-04-01

    Full Text Available Solar PV technology is one of the first among the various renewable energy technologies that have been adopted and accepted universally in order to meet the basic needs of generation of electricity. The objective of this paper is to propose a tri-cycle that utilises the application of stand-alone photovoltaic (PV system. A preliminary design and construction of a solar tri-cycle has been performed by evaluating and estimating the required panel size, battery capacity and motor power. Calculation in this paper exhibit that the solar power alone will be sufficient to operate a tri-cycle from one place to another.

  6. Photovoltaic and thermal energy conversion for solar powered satellites

    Science.gov (United States)

    Von Tiesenhausen, G. F.

    1976-01-01

    A summary is provided concerning the most important aspects of present investigations related to a use of solar power satellites (SPS) as a future source of terrestrial energy. General SPS characteristics are briefly considered, early work is reviewed, and a description of current investigations is presented. System options presently under study include a photovoltaic array, a thermionic system, and a closed Brayton cycle. Attention is given to system reference options, basic building blocks, questions of system analysis and engineering, photovoltaic conversion, and the utility interface. It is concluded that an SPS may be cost effective compared to terrestrial systems by 1995.

  7. Thermodynamic Analysis of Combined Cycle Power Plant

    Directory of Open Access Journals (Sweden)

    A.K.Tiwari,

    2010-04-01

    Full Text Available Air Bottoming Cycle (ABC can replace the heat recovery steam generator and the steam turbine of the conventionalcombined cycle plant. The exhaust energy of the topping gas turbine of existing combine cycle is sent to gas-air heat exchange, which heats the air in the secondary gas turbine cycle. In 1980’s the ABC was proposed as an alternative for the conventional steam bottoming cycle. In spite of the cost of reducing hardware installations it could achieve a thermal efficiency of 80%. The complete thermodynamic analysis of the system has been performed by using specially designed programme, enabling the variation of main independent variables. The result shows the gain in net work output as well as efficiency of combined cycle is 35% to 68%.

  8. Environmental control implications of generating electric power from coal. Appendix C. Gasification/combined-cycle power generation: comparison of alternative systems. 1977 technology status report. [246 references w. abstracts

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-12-01

    The technical, economic, and environmental aspects of low-Btu gasification/combined-cycle power-generation (LBG/CCPG) plants are assessed, using available published data. Six base-case plants, based on three different gasifiers and two different coals, are investigated. A representative combined power cycle is selected for analysis, and material and energy balances for the six systems are developed. Emissions of various air pollutants, including sulfur dioxide and nitrogen oxides, and discharge rates of aqueous effluents are also calculated. The costs of electricity produced are derived for the six systems, using estimated plant-investment and operating costs. These costs and the emissions of various pollutants are compared with those for a conventional 500-MWe coal-based power plant using flue-gas cleaning and in compliance with the federal New Source Performance Standards. Finally, the commercialization potential of coal-based combined-cycle plants, based on the technical feasibility of building a first plant in the 1985 period and on economic viability, is evaluated. This evaluation is based on the current status of research and development programs for various components of the combined-cycle plant, such as gas turbines and fuel-gas-cleaning systems, and on the status of the demonstration plant.

  9. Power and Efficiency Analysis of a Solar Central Receiver Combined Cycle Plant with a Small Particle Heat Exchanger Receiver

    Science.gov (United States)

    Virgen, Matthew Miguel

    Two significant goals in solar plant operation are lower cost and higher efficiencies. To achieve those goals, a combined cycle gas turbine (CCGT) system, which uses the hot gas turbine exhaust to produce superheated steam for a bottoming Rankine cycle by way of a heat recovery steam generator (HRSG), is investigated in this work. Building off of a previous gas turbine model created at the Combustion and Solar Energy Laboratory at SDSU, here are added the HRSG and steam turbine model, which had to handle significant change in the mass flow and temperature of air exiting the gas turbine due to varying solar input. A wide range of cases were run to explore options for maximizing both power and efficiency from the proposed CSP CCGT plant. Variable guide vanes (VGVs) were found in the earlier model to be an effective tool in providing operational flexibility to address the variable nature of solar input. Combined cycle efficiencies in the range of 50% were found to result from this plant configuration. However, a combustor inlet temperature (CIT) limit leads to two distinct Modes of operation, with a sharp drop in both plant efficiency and power occurring when the air flow through the receiver exceeded the CIT limit. This drawback can be partially addressed through strategic use of the VGVs. Since system response is fully established for the relevant range of solar input and variable guide vane angles, the System Advisor Model (SAM) from NREL can be used to find what the actual expected solar input would be over the course of the day, and plan accordingly. While the SAM software is not yet equipped to model a Brayton cycle cavity receiver, appropriate approximations were made in order to produce a suitable heliostat field to fit this system. Since the SPHER uses carbon nano-particles as the solar absorbers, questions of particle longevity and how the particles might affect the flame behavior in the combustor were addressed using the chemical kinetics software Chemkin

  10. State space model extraction of thermohydraulic systems Part I: a linear graph approach

    OpenAIRE

    Uren, Kenneth Richard; Schoor, George van

    2013-01-01

    This second paper in a two part series presents the application of a developed state space model extraction methodology applied to a Brayton cycle-based PCU (power conversion unit) of a PBMR (pebble bed modular reactor). The goal is to investigate if the state space extraction methodology can cope with larger and more complex thermohydraulic systems. In Part I the state space model extraction methodology for the purpose of control was described in detail and a state space represen...

  11. Biclique-colouring powers of paths and powers of cycles

    CERN Document Server

    Filho, Hélio B Macêdo; Machado, Raphael C S; de Figueiredo, Celina M H

    2012-01-01

    Biclique-colouring is a colouring of the vertices of a graph in such a way that no maximal complete bipartite subgraph with at least one edge is monochromatic. We show that it is co$\\mathcal{NP}$-complete to check if a colouring of vertices is a valid biclique-colouring, a result that justifies the search for structured classes where the biclique-colouring problem could be efficiently solved. We consider biclique-colouring restricted to powers of paths and powers of cycles. We determine the biclique-chromatic number of powers of paths and powers of cycles. The biclique-chromatic number of a power of a path $P_{n}^{k}$ is $\\max(2k + 2 - n, 2)$ if $n \\geq k + 1$ and exactly $n$ otherwise. The biclique-chromatic number of a power of a cycle $C_n^k$ is at most 3 if $n \\geq 2k + 2$ and exactly $n$ otherwise; we additionally determine the powers of cycles that are 2-biclique-colourable. All the proofs are algorithmic and we provide polynomial-time biclique-colouring algorithms for graphs in the investigated classes...

  12. Cermet-fueled reactors for multimegawatt space power applications

    International Nuclear Information System (INIS)

    The cermet-fueled reactor has evolved as a potential power source for a broad range of multimegawatt space applications. In particular, the fast spectrum reactor concept can be used to deliver 10s of megawatts of electric power for continuous, long term, unattended operation, and 100s of megawatts of electric power for times exceeding several hundred seconds. The system can also be utilized with either a gas coolant in a Brayton power conversion cycle, or a liquid metal coolant in a Rankine power conversion cycle. Extensive testing of the cermet fuel element has demonstrated that the fuel is capable of operating at very high temperatures under repeated thermal cycling conditions, including transient conditions which approach the multimegawatt burst power requirements. The cermet fuel test performance is reviewed and an advanced cermet-fueled multimegawatt nuclear reactor is described in this paper

  13. Nuclear power and the nuclear fuel cycle

    International Nuclear Information System (INIS)

    The report provides data and assessments of the status and prospects of nuclear power and the nuclear fuel cycle. The report discusses the economic competitiveness of nuclear electricity generation, the extent of world uranium resources, production and requirements, uranium conversion and enrichment, fuel fabrication, spent fuel treatment and radioactive waste management. A review is given of the status of nuclear fusion research

  14. An Advanced Light Weight Recuperator for Space Power Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nuclear Electric Propulsion (NEP) technology holds great promise for power and propulsion demands of NASA current and future deep space explorations. Closed Brayton...

  15. Energy systems. Tome 3: advanced cycles, low environmental impact innovative systems

    International Nuclear Information System (INIS)

    This third tome about energy systems completes the two previous ones by showing up advanced thermodynamical cycles, in particular having a low environmental impact, and by dealing with two other questions linked with the study of systems with a changing regime operation: - the time management of energy, with the use of thermal and pneumatic storage systems and time simulation (schedule for instance) of systems (solar energy type in particular); - the technological dimensioning and non-nominal regime operation studies. Because this last topic is particularly complex, new functionalities have been implemented mainly by using the external classes mechanism, which allows the user to freely personalize his models. This tome is illustrated with about 50 examples of cycles modelled with Thermoptim software. Content: foreword; 1 - generic external classes; 2 - advanced gas turbine cycles; 3 - evaporation-concentration, mechanical steam compression, desalination, hot gas drying; 4 - cryogenic cycles; 5 - electrochemical converters; 6 - global warming, CO2 capture and sequestration; 7 - future nuclear reactors (coupled to Hirn and Brayton cycles); 8 - thermodynamic solar cycles; 10 - pneumatic and thermal storage; 11 - calculation of thermodynamic solar facilities; 12 - problem of technological dimensioning and non-nominal regime; 13 - exchangers modeling and parameterizing for the dimensioning and the non-nominal regime; 14 - modeling and parameterizing of volumetric compressors; 15 - modeling and parameterizing of turbo-compressors and turbines; 16 - identification methodology of component parameters; 17 - case studies. (J.S.)

  16. Comparative study of alternative ORC-based combined power systems to exploit high temperature waste heat

    International Nuclear Information System (INIS)

    Highlights: • Three ORC-based combined systems for ICE exhaust waste heat recovery are studied. • A parametric investigation is conducted under several typical engine conditions. • Performance is evaluated considering six thermodynamic, techno-economic indexes. • DORC distinguishes among other solutions for its highest energy recovery capacity. • TEG–ORC system becomes attractive when exhaust temperature is relatively low. - Abstract: In this paper, various combined power systems which regard organic Rankine cycle (ORC) as bottoming cycle to recover engine’s high temperature exhaust heat are proposed. The topping recovery cycle includes steam Rankine cycle (RC), Brayton cycle (BC) and thermoelectric generator (TEG). Comprehensive evaluations are conducted under five typical engine conditions, ranging from high load to low load, and system performance is assessed in terms of many thermodynamic indexes, such as net output power, thermal efficiency, recovery efficiency and exergy efficiency. Besides that, the irreversibility of each component is also discussed in detail. R123, R245fa and R600a for ORC system are considered to analyze the influence of working fluids. Considering the system techno-economy, the turbine size parameter (SP) and heat transfer capacity (UA) are chosen as key indicators. The results show that compared with the other two investigated approaches, dual-loop ORC (DORC) possesses the highest energy exploitation capacity under the whole operating region, with a 5.57% increase of fuel economy under the rated condition, but its values of SP and UA are large as well. TEG–ORC becomes appealing while under the relatively low load

  17. Stockholm Power Tech. Power systems

    International Nuclear Information System (INIS)

    The proceedings from this symposium is presented in six volumes: Invited speakers' sessions; Power systems; Power electronics; High-voltage technology; Electrical machines and drives; and Information and control systems. This report covers the power systems volume. Separate abstracts have been prepared for 141 of the 145 papers in this volume

  18. Stockholm Power Tech. Power systems

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-11-01

    The proceedings from this symposium is presented in six volumes: Invited speakers` sessions; Power systems; Power electronics; High-voltage technology; Electrical machines and drives; and Information and control systems. This report covers the power systems volume. Separate abstracts have been prepared for 141 of the 145 papers in this volume

  19. Wind power in power systems

    CERN Document Server

    Ackermann, Thomas

    2012-01-01

    The second edition of the highly acclaimed Wind Power in Power Systems has been thoroughly revised and expanded to reflect the latest challenges associated with increasing wind power penetration levels. Since its first release, practical experiences with high wind power penetration levels have significantly increased. This book presents an overview of the lessons learned in integrating wind power into power systems and provides an outlook of the relevant issues and solutions to allow even higher wind power penetration levels. This includes the development of standard wind turbine sim

  20. Pre-design and life cycle cost analysis of a hybrid power system for rural and remote communities in Afghanistan

    Directory of Open Access Journals (Sweden)

    Mir Sayed Shah Danish

    2014-08-01

    Full Text Available In view of the present situation of the Afghanistan electricity sector, the photovoltaic and diesel generator stand-alone hybrid power system is increasingly attractive for application in rural and remote communities. Thousands of rural communities in Afghanistan depend solely on traditional kerosene for illumination and rarely have access to electricity sources such as DC battery for radio and other small appliances. This study is conducted to offer real-life solution to this problem. The hybrid system is investigated to meet the domestic load demand that is estimated based on the communities’ electricity consumption culture. At first, customary pre-design is pursued. Afterwards, the break-even point and net present value algorithms are applied for economic analysis. That makes this study differ from the previous academic literature. The concepts developed in this study are targeted for a cost-effective hybrid system, which is appropriate for rural and remote residents’ lifestyle change and improvement. Based on the academic research methods, overall analysis procedures can fit as an analogy, especially for developing countries.

  1. Cycling of conventional power plants: Technical limits and actual costs

    International Nuclear Information System (INIS)

    Highlights: • Literature reports a wide range of cycling parameters (technical and cost-related). • The impact of different cycling parameters is assessed. • The German 2013 system is studied as a case study. • Even for stringent parameters, the dynamic limit of the portfolio is not reached. • Cycling costs can be reduced with 40% when taken into account in the scheduling. - Abstract: Cycling of conventional generation units is an important source of operational flexibility in the electricity generation system. Cycling is changing the power output of conventional units by means of ramping and switching (starting up and shutting down). In the literature, a wide range of technical and cost-related cycling parameters can be found. Different studies allocate different cycling parameters to similar generation units. This paper assesses the impact of different cycling parameters allocated to a conventional generation portfolio. Both the technical limitations of power plants and all costs related to cycling are considered. The results presented in this paper follow from a unit commitment model, used for a case study based on the German 2013 system. The conventional generation portfolio has to deliver different residual load time series, corresponding to different levels of renewables penetration. The study shows, under the assumptions made, that although the dynamic limits of some units are reached, the limits of the conventional generation portfolio as a whole are not reached, even if stringent dynamic parameters are assigned to the generation portfolio and a highly variable residual load is imposed to the system. The study shows also the importance of including full cycling costs in the unit commitment scheduling. The cycling cost can be reduced by up to 40% when fully taken into account

  2. Computational tool for simulation of power and refrigeration cycles

    Science.gov (United States)

    Córdoba Tuta, E.; Reyes Orozco, M.

    2016-07-01

    Small improvement in thermal efficiency of power cycles brings huge cost savings in the production of electricity, for that reason have a tool for simulation of power cycles allows modeling the optimal changes for a best performance. There is also a big boom in research Organic Rankine Cycle (ORC), which aims to get electricity at low power through cogeneration, in which the working fluid is usually a refrigerant. A tool to design the elements of an ORC cycle and the selection of the working fluid would be helpful, because sources of heat from cogeneration are very different and in each case would be a custom design. In this work the development of a multiplatform software for the simulation of power cycles and refrigeration, which was implemented in the C ++ language and includes a graphical interface which was developed using multiplatform environment Qt and runs on operating systems Windows and Linux. The tool allows the design of custom power cycles, selection the type of fluid (thermodynamic properties are calculated through CoolProp library), calculate the plant efficiency, identify the fractions of flow in each branch and finally generates a report very educational in pdf format via the LaTeX tool.

  3. Gas--steam turbine combined cycle power plants

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.

    1978-10-01

    The purpose of this technology evaluation is to provide performance and cost characteristics of the combined gas and steam turbine, cycle system applied to an Integrated Community Energy System (ICES). To date, most of the applications of combined cycles have been for electric power generation only. The basic gas--steam turbine combined cycle consists of: (1) a gas turbine-generator set, (2) a waste-heat recovery boiler in the gas turbine exhaust stream designed to produce steam, and (3) a steam turbine acting as a bottoming cycle. Because modification of the standard steam portion of the combined cycle would be necessary to recover waste heat at a useful temperature (> 212/sup 0/F), some sacrifice in the potential conversion efficiency is necessary at this temperature. The total energy efficiency ((electric power + recovered waste heat) divided by input fuel energy) varies from about 65 to 73% at full load to 34 to 49% at 20% rated electric power output. Two major factors that must be considered when installing a gas--steam turbine combines cycle are: the realiability of the gas turbine portion of the cycle, and the availability of liquid and gas fuels or the feasibility of hooking up with a coal gasification/liquefaction process.

  4. Exergetic comparison of two different cooling technologies for the power cycle of a thermal power plant

    International Nuclear Information System (INIS)

    Exergetic analysis is without any doubt a powerful tool for developing, evaluating and improving an energy conversion system. In the present paper, two different cooling technologies for the power cycle of a 50 MWe solar thermal power plant are compared from the exergetic viewpoint. The Rankine cycle design is a conventional, single reheat design with five closed and one open extraction feedwater heaters. The software package GateCycle is used for the thermodynamic simulation of the Rankine cycle model. The first design configuration uses a cooling tower while the second configuration uses an air cooled condenser. With this exergy analysis we identify the location, magnitude and the sources or thermodynamic inefficiencies in this thermal system. This information is very useful for improving the overall efficiency of the power system and for comparing the performance of both technologies.

  5. GT-MHR international project of high-temperature helium cooled reactor with direct gas-turbine power conversion cycle

    International Nuclear Information System (INIS)

    Full text: The international project of gas-turbine modular helium-cooled reactor (GT-MHR) presented in the report is a realization of high-temperature technology and is based on the experience with helium-cooled reactors with ceramic fuel particles and on innovative solutions concerning power conversion system with closed gas-turbine cycle and turbomachine with electromagnetic bearings. The international GT-MHR Project is currently being jointly developed by USA and Russia for disposition of excessive weapon-grade plutonium. For commercial electricity generation, the reactor will use uranium fuel. The GT-MHR combines a gas-cooled modular helium reactor (MHR) and a highly efficient integrated gas-turbine power conversion system (Brayton cycle) with expected cycle efficiency up to 48%. The reactor and power conversion unit are located in an underground concrete silo. The GT-MHR technical characteristics and design features assure: high level of passive safety that completely prevents core melting in accidents with any scenario, including full loss of inert coolant; low level of thermal and radiation impact to the environment; capability to use various fuels in the core (e.g. low-enriched uranium, mixed uranium-thorium and uranium-plutonium fuel, or plutonium fuel) without modifying the core design; meeting the non-proliferation requirements through technology and properties of ceramic fuel particles; capability to achieve coolant temperatures of up to 1000 deg. C, which is needed for various industrial processes; high efficiency of electricity generation. A whole complex of research and development activities is being carried out by RRC KI, OKBM, VNIINM, 'Lutch', and other Russian organizations in order to support key design solutions, primarily on fuel, turbomachine with electromagnetic bearings, structural materials, vessels and computer codes. At present, the GT-MHR capability to generate high-grade heat at temperatures up to 1000 deg. C makes it the only

  6. Design and Implementation of A PV Powered Tri-Cycle

    OpenAIRE

    Soumya Das; Pradip K Sadhu; Suprava Chakraborty; Saumen Dhara; Shramabati Sen

    2016-01-01

    Solar PV technology is one of the first among the various renewable energy technologies that have been adopted and accepted universally in order to meet the basic needs of generation of electricity. The objective of this paper is to propose a tri-cycle that utilises the application of stand-alone photovoltaic (PV) system. A preliminary design and construction of a solar tri-cycle has been performed by evaluating and estimating the required panel size, battery capacity and motor power. Calcul...

  7. Power generation costs for alternate reactor fuel cycles

    International Nuclear Information System (INIS)

    The total electric generating costs at the power plant busbar are estimated for various nuclear reactor fuel cycles which may be considered for power generation in the future. The reactor systems include pressurized water reactors (PWR), heavy-water reactors (HWR), high-temperature gas cooled reactors (HTGR), liquid-metal fast breeder reactors (LMFBR), light-water pre-breeder and breeder reactors (LWPR, LWBR), and a fast mixed spectrum reactor (FMSR). Fuel cycles include once-through, uranium-only recycle, and full recycle of the uranium and plutonium in the spent fuel assemblies. The U3O8 price for economic transition from once-through LWR fuel cycles to both PWR recycle and LMFBR systems is estimated. Electric power generation costs were determined both for a reference set of unit cost parameters and for a range of uncertainty in these parameters. In addition, cost sensitivity parameters are provided so that independent estimations can be made for alternate cost assumptions

  8. Test Requirements and Conceptual Design for a Potassium Test Loop to Support an Advanced Potassium Rankine Cycle Power Conversion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Yoder, JR.G.L.

    2006-03-08

    Parameters for continuing the design and specification of an experimental potassium test loop are identified in this report. Design and construction of a potassium test loop is part of the Phase II effort of the project ''Technology Development Program for an Advanced Potassium Rankine Power Conversion System''. This program is supported by the National Aeronautics and Space Administration. Design features for the potassium test loop and its instrumentation system, specific test articles, and engineered barriers for ensuring worker safety and protection of the environment are described along with safety and environmental protection requirements to be used during the design process. Information presented in the first portion of this report formed the basis to initiate the design phase of the program; however, the report is a living document that can be changed as necessary during the design process, reflecting modifications as additional design details are developed. Some portions of the report have parameters identified as ''to be determined'' (TBD), reflecting the early stage of the overall process. In cases where specific design values are presently unknown, the report attempts to document the quantities that remain to be defined in order to complete the design of the potassium test loop and supporting equipment.

  9. Performance assessment and optimization of a combined heat and power system based on compressed air energy storage system and humid air turbine cycle

    International Nuclear Information System (INIS)

    Highlights: • A combined heat and power system based on CAES and HAT is proposed. • The design and modeling of the CAES–HAT based CHP system are laid out. • The performance assessment of the proposed system is carried out. • The system optimization is conducted to decide the maximum conditions. - Abstract: Renewable energy based power sources have grown rapidly in the past few years owing to the dual constraint of climate change and pollution control. Compressed air energy storage (CAES), as a large-scale energy storage system (ESS) technology, has huge potential to manage the intermittent renewable energy based power sources effectively. However, the compression heat generated during charge and waste heat carried in turbine exhaust during discharge are not fully recuperated in current stage. A combined heat and power (CHP) system consisting of a CAES system and a humid air turbine (HAT) system is proposed to utilize the both types of heat energy. The proposed system can boost the power output, enhance performance and improve efficiency through a simultaneous supply of power and heat. The thermodynamic analysis shows that the expansion train power can be improved about 26% compared with the conventional CAES system. The parametric analysis reveals that the exergy efficiency increases with the turbine inlet temperature (TIT) of high pressure turbine (HPT) and inlet pressure of low pressure turbine (LPT), but decreases with the TIT of LPT, L/G ratio and dry air inlet temperature of saturator. Meanwhile, the system optimization is carried out via particle swarm optimization (PSO) to determine the maximum power and exergy efficiency conditions

  10. Nuclear power and the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Australian Nuclear Science and Technology Organization maintains an ongoing assessment of the world's nuclear technology developments, as a core activity of its Strategic Plan. This publication reviews the current status of the nuclear power and the nuclear fuel cycle in Australia and around the world. Main issues discussed include: performances and economics of various types of nuclear reactors, uranium resources and requirements, fuel fabrication and technology, radioactive waste management. A brief account of the large international effort to demonstrate the feasibility of fusion power is also given. 11 tabs., ills

  11. Development of web based performance analysis program for nuclear power plant turbine cycle

    International Nuclear Information System (INIS)

    Performance improvement of turbine cycle affects economic operation of nuclear power plant. We developed performance analysis system for nuclear power plant turbine cycle. The system is based on PTC (Performance Test Code), that is estimation standard of nuclear power plant performance. The system is developed using Java Web-Start and JSP(Java Server Page)

  12. Discussion of mechanical design for pressured cavity-air-receiver in solar power tower system

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Zhilin; Zhang, Yaoming; Liu, Deyou; Wang, Jun; Liu, Wei [Hohai Univ., Nanjing (China). New Materials and Energy Sources Research and Exploitation Inst.

    2008-07-01

    In 2005, Hohai university and Nanjing Chunhui science and technology Ltd. of China, cooperating with Weizmann Institute of Science and EDIG Ltd. of Israel, built up a 70kWe solar power tower test plant in Nanjing, Jiangsu province, China, which was regarded as the first demonstration project to demonstrate the feasibility of solar power tower system in China. The system consists of heliostats field providing concentrated sunlight, a solar tower with a height of 33 meter, a pressured cavity-air-receiver transforming solar energy to thermal energy, a modified gas turbine adapting to solar power system, natural gas subsystem for solar-hybrid generation, cooling water subsystem for receiver and CPC, controlling subsystem for whole plant, et al. In this system, air acts as actuating medium and the system works in Brayton cycle. Testing results show that solar power tower system is feasible in China. To promote the development of solar powered gas turbine system and the pressured cavity-air-receiver technology in China, it is necessary to study the mechanical design for pressured Cavity-air-receiver. Mechanical design of pressured cavity-air-receiver is underway and some tentative principles for pressured cavity-air-receiver design, involving in power matching, thermal efficiency, material choosing, and equipment security and machining ability, are presented. At the same time, simplified method and process adapted to engineering application for the mechanical design of pressured cavity-air-receiver are discussed too. Furthermore, some design parameters and appearance of a test sample of pressured cavity-air-receiver designed in this way is shown. It is appealed that, in China, the research in this field should be intensified and independent knowledge patents for pivotal technological equipments such as receiver in solar power tower system should be formed. (orig.)

  13. Development of an Anti-Vibration Controller for Magnetic Bearing Cooling Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal outlines a program to develop a vibration-free reverse-Brayton cycle cooling system using specially-tuned magnetic bearings. Such a system is critical...

  14. POWER CYCLE AND STRESS ANALYSES FOR HIGH TEMPERATURE GAS-COOLED REACTOR

    International Nuclear Information System (INIS)

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold (1) efficient low cost energy generation and (2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were demonstrated in this study. A three-shaft design with three turbines and four compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with three stages of reheat were investigated. An intermediate heat transport loop for transporting process heat to a High Temperature Steam Electrolysis (HTSE) hydrogen production plant was used. Helium, CO2, and a 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative component size were estimated for the different working fluids. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. This gives some insight into the sensitivity of these cycles to

  15. Study of Cycle Diagrams of Power Plants with MHD Generators

    International Nuclear Information System (INIS)

    A gas-, or liquid-fuel- fired, open-cycle MHD generator, combined with a steam plant, has in the nearest future most promising features. The technical realization of such a system requires the solving of many problems, resulting in some modification of the typical MHD-steam power cycle. In the paper presented, the authors propose and discuss the cycle diagrams of a combined 500 MW MHD-steam power plant. Residual oil burnt,in preheated air, without any oxygen enrichment, has been assumed. The MHD generator works as topping unit, followed by the steam plant. Overall efficiency of the combined plant is about 53%. Based on the cycle diagram, solutions to the most important difficulties have been proposed, namely: (a) regenerative air preheat, (b) generator and combustor wall cooling heat utilization, (c) exhaust gas temperature reduction, (d) compressor intercooler heat utilization, (e) separation of MHD generator and steam cycle. The influence of the most important factors upon the overall efficiency has been discussed: generator and combustor cooling intensity, exhaust gas temperature, heat exchanger system, steam cycle parameters. Constant air pressure (4 kg/cm2 maximum) and preheat temperature (1400°C) has been assumed. Some methods of increasing of combined plant thermal efficiency by reduction of heat losses in cycle diagram elements have been suggested. (author)

  16. Analysis of the integrated characteristics of the CPS (combined power system) of a bottoming organic Rankine cycle and a diesel engine

    International Nuclear Information System (INIS)

    This study analyses the integrated characteristics of a CPS (combined power system) consisting of a topping diesel engine and a bottoming ORC (organic Rankine cycle). Two models (an integrated and a cascaded CPS model) for the same CPS have been developed based on the experimental data. The results show that the process of integrating the ORC causes a substantial decrease in the power output of the ICE subsystem, this integration outweighs the corresponding power output increasing from the ORC subsystem, and the overall thermal efficiency of the integrated CPS model is higher than that of the standalone ICE system model but lower than that of the cascaded CPS model, which can be determined from the pressure drop on the exhaust gas side of the ORC evaporator and is reflected in the overall thermodynamic performance. Moreover, the matching characteristics of the heat-transfer and fluid flow conditions in a fixed sized evaporator are analysed in the integrated CPS model. The results show that when the intake airflow rate decreases, the temperature of the exhaust gas exiting the evaporator decreases to the minimum allowed temperature, which is below the dew point, and this low-temperature might cause corrosion problems in the subsequent components. - Highlights: • Two ICE-ORC CPS models are developed based on experimental data. • Integrated performances are studied at different intake airflow rates. • Influence of the bottoming ORC on the toping ICE is analysed. • The coupling of the fluid flow and the heat-transfer in evaporator is calculated

  17. Energy and exergy analyses of a modified combined cooling, heating, and power system using supercritical CO2

    International Nuclear Information System (INIS)

    In aim to reduce the greenhouse-gas emissions and improve the low-grade heat efficiency, a modified CCHP (combined cooling, heating, and power) system is proposed using supercritical CO2. This cycle combines a Brayton cycle and a transcritical ejector refrigeration cycle by adding an extraction turbine. A mathematical model is developed to simulate the modified CCHP system. Parametric analysis and exergy analysis are conducted to investigate the effects of key thermodynamic parameters on the performance and exergy destruction. Due to the difficulties in the thermal efficiency evaluation for CCHP system, a more practical performance metric is introduced in order to quantify system performance. The results indicate that both higher extraction rate and extraction pressure are helpful to gain more refrigeration. For the conditions considered, the exergy efficiency of the modified CCHP with the extraction turbine is higher than that of the CCHP with the no-extraction turbine from 10.4% to 22.5%. Furthermore, there is a large increase in the turbine power output and the exergy efficiency with increased turbine inlet temperature. It reveals that a rise of heat source quality benefits the system performance. - Highlights: • A modified combined cooling, heating and power system (CCHP) is proposed using supercritical CO2. • A more practical performance metric is introduced in order to quantify system thermal efficiency. • The ratio of COP between the new CCHP cycle and the transcritical CO2 ejector cycle increases from 1.29 to 2.43. • The extraction turbine is helpful to gain more refrigeration. • The exergy efficiency of the modified CCHP with extraction turbine is higher than that of CCHP with no-extraction turbine

  18. Design of a gigawatt space solar power satellite using optical concentrator system

    Science.gov (United States)

    Dessanti, B.; Komerath, N.; Shah, S.

    A 1-gigawatt space solar power satellite using a large array of individually pointable optical elements is identified as the key mass element of a large scale space solar power architecture using the Space Power Grid concept. The proposed satellite design enables a significant increase in specific power. Placed in sun-synchronous dynamic orbits near 2000km altitude, these satellites can maintain the constant solar view requirement of GEO-based architectures, while greatly reducing the beaming distance required, decreasing the required antenna size and in turn the overall system mass. The satellite uses an array of individually pointable optical elements (which we call a Mirasol Concentrator Array) to concentrate solar energy to an intensified feed target that feeds into the main heater of the spacecraft, similar conceptually to heliostat arrays. The spacecraft then utilizes Brayton cycle conversion to take advantage of non-linear power level scaling in order to generate high specific power values. Using phase array antennas, the power is then beamed at a millimeter wave frequency of 220GHz down to Earth. The design of the Mirasol concentrator system will be described and a detailed mass estimation of the system is developed. The technical challenges of pointing the elements and maintaining constant solar view is investigated. An end-to-end efficiency analysis is performed. Subsystem designs for the spacecraft are outlined. A detailed mass budget is refined to reflect reductions in uncertainty of the spacecraft mass, particularly in the Mirasol system. One of the key mass drivers of the spacecraft is the active thermal control system. The design of a lightweight thermal control system utilizing graphene sheets is also detailed.

  19. Limit cycles in quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, Patrick

    2015-04-27

    In this thesis we investigate Limit Cycles in Quantum Systems. Limit cycles are a renormalization group (RG) topology. When degrees of freedom are integrated out, the coupling constants flow periodically in a closed curve. The presence of limit cycles is restricted by the necessary condition of discrete scale invariance. A signature of discrete scale invariance and limit cycles is log-periodic behavior. The first part of this thesis is concerned with the study of limit cycles with the similarity renormalization group (SRG). Limit cycles are mainly investigated within conventional renormalization group frameworks, where degrees of freedom, which are larger than a given cutoff, are integrated out. In contrast, in the SRG potentials are unitarily transformed and thereby obtain a band-diagonal structure. The width of the band structure can be regarded as an effective cutoff. We investigate the appearance of limit cycles in the SRG evolution. Our aim is to extract signatures as well as the scaling factor of the limit cycle. We consider the 1/R{sup 2}-potential in a two-body system and a three-body system with large scattering lengths. Both systems display a limit cycle. Besides the frequently used kinetic energy generator we apply the exponential and the inverse generator. In the second part of this thesis, Limit Cycles at Finite Density, we examine the pole structure of the scattering amplitude for distinguishable fermions at zero temperature in the medium. Unequal masses and a filled Fermi sphere for each fermion species are considered. We focus on negative scattering lengths and the unitary limit. The properties of the three-body spectrum in the medium and implications for the phase structure of ultracold Fermi gases are discussed.

  20. Limit cycles in quantum systems

    International Nuclear Information System (INIS)

    In this thesis we investigate Limit Cycles in Quantum Systems. Limit cycles are a renormalization group (RG) topology. When degrees of freedom are integrated out, the coupling constants flow periodically in a closed curve. The presence of limit cycles is restricted by the necessary condition of discrete scale invariance. A signature of discrete scale invariance and limit cycles is log-periodic behavior. The first part of this thesis is concerned with the study of limit cycles with the similarity renormalization group (SRG). Limit cycles are mainly investigated within conventional renormalization group frameworks, where degrees of freedom, which are larger than a given cutoff, are integrated out. In contrast, in the SRG potentials are unitarily transformed and thereby obtain a band-diagonal structure. The width of the band structure can be regarded as an effective cutoff. We investigate the appearance of limit cycles in the SRG evolution. Our aim is to extract signatures as well as the scaling factor of the limit cycle. We consider the 1/R2-potential in a two-body system and a three-body system with large scattering lengths. Both systems display a limit cycle. Besides the frequently used kinetic energy generator we apply the exponential and the inverse generator. In the second part of this thesis, Limit Cycles at Finite Density, we examine the pole structure of the scattering amplitude for distinguishable fermions at zero temperature in the medium. Unequal masses and a filled Fermi sphere for each fermion species are considered. We focus on negative scattering lengths and the unitary limit. The properties of the three-body spectrum in the medium and implications for the phase structure of ultracold Fermi gases are discussed.

  1. Compact Fusion Advanced Rankine (CFARII) power cycle

    International Nuclear Information System (INIS)

    The Compact Fusion Advanced Rankine (CFARII) power cycle is a direct plasma energy conversion scheme for inertial fusion (ICF) and magnetically-insulated, inertially confined fusion (MICF) reactors utilizing: (1) conversion of plasma thermal ionization and thermal energy into kinetic energy of a supersonic plasma jet, (2) conversion of the plasma jet kinetic energy into DC electricity by slowing down in an ''impulse'' type of magnetohydrodynamic (MHD) generator, and (3) condensation and heat rejection of the exhaust plasma on droplets of recirculating condensate (''raindrop'' condensor). A preliminary evaluation of a particular reference case CFARII Balance-of-Plant (BoP) is found sufficiently attractive (52% gross cycle efficiency, 40 million 1991 $ BoP for 1 GWe gross electric) to warrant further work on several design issues

  2. Effects of backlash and dead band on temperature control of the primary loop of a conceptual nuclear Brayton space powerplant

    Science.gov (United States)

    Petrick, E. J.

    1973-01-01

    An analytical study was made of the stability of a closed-loop liquid-lithium temperature control of the primary loop of a conceptual nuclear Brayton space powerplant. The operating point was varied from 20 to 120 percent of design. A describing-function technique was used to evaluate the effects of temperature dead band and control coupling backlash. From the system investigation, it was predicted that a limit cycle will not exist with a temperature dead band, but a limit cycle will not exist when backlash is present. The results compare favorably with a digital computer simulation.

  3. Brayton Isotope Power System (BIPS). Phase I: Integrated Program Plan (IPP). Report 75-311574A

    Energy Technology Data Exchange (ETDEWEB)

    1976-05-27

    The government, AIRPHX, AIRLA, and contractor BIPS program coordination efforts are discussed. These coordination efforts are essential for defining program objectives, and achieving these objectives in an efficient manner. The IPP outlines a long range effort intended to: (a) develop end product confidence; (b) identify government and contractor activities pertinent and contributory to BIPS development; (c) recommend government and contractor activities required to ensure BIPS program success; (d) establish activity priorities based on program cost and schedule impacts, and achievement of technical objectives; (e) coordinate the efforts of contributing agencies; (f) provide general information and, to a limited extent, BIPS program-related development activity status to interested individuals and agencies; and (g) provide contractor team program planning guidance.

  4. Brayton Isotope Power System (BIPS). Phase I: Integrated Program Plan (IPP). Report 75-311574A

    International Nuclear Information System (INIS)

    The government, AIRPHX, AIRLA, and contractor BIPS program coordination efforts are discussed. These coordination efforts are essential for defining program objectives, and achieving these objectives in an efficient manner. The IPP outlines a long range effort intended to: (a) develop end product confidence; (b) identify government and contractor activities pertinent and contributory to BIPS development; (c) recommend government and contractor activities required to ensure BIPS program success; (d) establish activity priorities based on program cost and schedule impacts, and achievement of technical objectives; (e) coordinate the efforts of contributing agencies; (f) provide general information and, to a limited extent, BIPS program-related development activity status to interested individuals and agencies; and (g) provide contractor team program planning guidance

  5. Assessment of solar options for small power systems applications. Volume III. Analysis of concepts

    Energy Technology Data Exchange (ETDEWEB)

    Laity, W.W.; Aase, D.T.; Apley, W.J.; Bird, S.P.; Drost, M.K.; Garrett-Price, B.A.; Williams, T.A.

    1980-09-01

    A comparative analysis of solar thermal conversion concepts that are potentially suitable for development as small electric power systems (1 to 10 MWe) is given. Seven generic types of collectors, together with associated subsystems for electric power generation, were considered. The collectors can be classified into three categories: (1) two-axis tracking (with compound-curvature reflecting surfaces; (2) one-axis tracking (with single-curvature reflecting suraces; and (3) nontracking (with low-concentration reflecting surfaces). All seven collectors were analyzed in conceptual system configurations with Rankine-cycle engines. In addition, two of the collectors (the Point Focus Central Receiver and the Point Focus Distributed Receiver) were analyzed with Brayton-cycle engines, and the latter of the two also was analyzed with Stirling-cycle engines. This volume describes the systems analyses performed on all the alternative configurations of the seven generic collector concepts and the results obtained. The SOLSTEP computer code used to determine each configuration's system cost and performance is briefly described. The collector and receiver performance calculations used are also presented. The capital investment and related costs that were obtained from the systems studies are presented, and the levelized energy costs are given as a function of capacity factor obtained from the systems studies. Included also are the values of the other attributes used in the concepts' final ranking. The comments, conclusions, and recommendations developed by the PNL study team during the concept characterization and systems analysis tasks of the study are presented. (WHK)

  6. Assessment of solar options for small power systems applications. Volume I. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    Laity, W.W.; Aase, D.T.; Apley, W.J.; Bird, S.P.; Currie, J.W.; Drost, M.K.; Jannol, M.; Schulte, S.C.; Sutey, A.M.; Williams, T.A.

    1979-09-01

    A comparative analysis of solar thermal conversion concepts that are potentially suitable for development as small electric power systems (1 to 10 MWe) is presented. Seven generic types of collectors, together with associated subsystems for electric power generation, were considered. The collectors can be classified into three categories: (1) two-axis tracking (with compound-curvature reflecting surfaces), (2) one-axis tracking (with single-curvature reflecting surfaces), and (3) nontracking (with low-concentration reflecting surfaces). All seven collectors were analyzed in conceptual system configurations with Rankine-cycle engines. In addition, two of the collectors (the Point Focus Central Receiver and the Point Focus Distributed Receiver) were analyzed with Brayton-cycle engines, and the latter of the two also was analyzed with Stirling-cycle engines. With these engine options, 10 systems were formulated for analysis. Conceptual designs developed for the 10 systems were based on common assumptions of available technology in the 1990 to 2000 time frame. The computer code SOLSTEP was used to analyze the thermodynamic performance characteristics and energy costs of the 10 concepts. Year-long simulations were performed using meteorological and insolation data for Barstow, California as input to the code. Results for each concept include levelized energy costs and capacity factors for various combinations of storage capacity and collector field size. For all 10 concepts, subjective values were estimated for four additional power plant characteristics: plant flexibility, forced outage rate, environmental and safety effects, and R and D necessary for commercialization. Multiattribute utility methodology was used to rank the 10 concepts. (WHK)

  7. ITER fuel cycle systems

    International Nuclear Information System (INIS)

    This document records the assumptions under which the ITER Fuel Systems cost estimates were prepared. These are order of magnitude estimates, obtained without flow sheet or detailed equipment analysis by applying factors, ratios, and escalation to the known cost of an installation considered to be similar. The estimates include equipment and installation costs for each component. (5 figs., 16 refs.)

  8. Bottoming cycles for electric energy generation: Parametric investigation of available and innovative solutions for the exploitation of low and medium temperature heat sources

    International Nuclear Information System (INIS)

    Many industrial processes and conventional fossil fuel energy production systems used in small-medium industries, such as internal combustion engines and gas turbines, provide low or medium temperature (i.e., 200-500 oC) heat fluxes as a by-product, which are typically wasted in the environment. The possibility of exploiting this wasted heat, converting it into electric energy by means of different energy systems, is investigated in this article, by extending the usual range of operation of existing technologies or introducing novel concepts. In particular, among the small size bottoming cycle technologies, the identified solutions which could allow to improve the energy saving performance of an existing plant by generating a certain amount of electric energy are: the Organic Rankine Cycle, the Stirling engine and the Inverted Brayton Cycle; this last is an original thermodynamic concept included in the performed comparative analysis. Moreover, this paper provides a parametric investigation of the thermodynamic performance of the different systems; in particular, for the Inverted Brayton Cycle, the effects of the heat source characteristics and of the cycle design parameters on the achievable efficiency and specific power are shown. Furthermore, a comparison with other existing energy recovery solutions is performed, in order to assess the market potential. The analysis shows that the highest electric efficiency values, more than 20% with reference to the input heat content, are obtained with the Organic Rankine Cycle, while not negligible values of efficiency (up to 10%) are achievable with the Inverted Brayton Cycle, if the available temperature is higher than 400 oC.

  9. Advanced Organic Vapor Cycles for Improving Thermal Conversion Efficiency in Renewable Energy Systems

    OpenAIRE

    Ho, Tony

    2012-01-01

    The Organic Flash Cycle (OFC) is proposed as a vapor power cycle that could potentially increase power generation and improve the utilization efficiency of renewable energy and waste heat recovery systems. A brief review of current advanced vapor power cycles including the Organic Rankine Cycle (ORC), the zeotropic Rankine cycle, the Kalina cycle, the transcritical cycle, and the trilateral flash cycle is presented. The premise and motivation for the OFC concept is that essentially by impro...

  10. High Efficiency Nuclear Power Plants Using Liquid Fluoride Thorium Reactor Technology

    Science.gov (United States)

    Juhasz, Albert J.; Rarick, Richard A.; Rangarajan, Rajmohan

    2009-01-01

    An overall system analysis approach is used to propose potential conceptual designs of advanced terrestrial nuclear power plants based on Oak Ridge National Laboratory (ORNL) Molten Salt Reactor (MSR) experience and utilizing Closed Cycle Gas Turbine (CCGT) thermal-to-electric energy conversion technology. In particular conceptual designs for an advanced 1 GWe power plant with turbine reheat and compressor intercooling at a 950 K turbine inlet temperature (TIT), as well as near term 100 MWe demonstration plants with TITs of 950 and 1200 K are presented. Power plant performance data were obtained for TITs ranging from 650 to 1300 K by use of a Closed Brayton Cycle (CBC) systems code which considered the interaction between major sub-systems, including the Liquid Fluoride Thorium Reactor (LFTR), heat source and heat sink heat exchangers, turbo-generator machinery, and an electric power generation and transmission system. Optional off-shore submarine installation of the power plant is a major consideration.

  11. The use of absorption refrigeration systems in combined cycle power plants; Empleo de sistemas de refrigeracion por absorcion en plantas de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, H.; Ambriz, J.J.; Vargas, M.; Godinez, M.; Gomez, F.; Valdez, L.; Pantoja, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Departamento de Ingenieria de Procesos e Hidraulica, Mexico D. F. (Mexico)

    1995-12-31

    Day after day the electric power generation tends to be done in the most efficient way in order to diminish the generation costs and the rate of environmental pollution per KWh generated. This paper discusses the application of absorption refrigeration systems for the cooling of the air entering the compressor of a gas turbine in a combined cycle, in order to increase the mass air flow and with it the turbine output. The flows with remanent energy content that are not used in a combined cycle can be used for the operation of the absorption refrigeration system. This way, the required thermal energy for the cooling system is free. With this system it is possible to raise the gas turbine generation output from 5% to 25%. [Espanol] La generacion electrica dia con dia pretende realizarse de la manera mas eficiente posible con el objeto de disminuir los costos de generacion y la tasa de contaminacion ambiental por Kwh generado. En el presente trabajo se introduce la aplicacion de sistemas de refrigeracion por absorcion para el enfriamiento del aire de entrada al compresor de la turbina de gas de un ciclo combinado, con el objeto de aumentar el flujo masico del aire y con ello la potencia de salida de la turbina. Las corrientes con contenido remanente de energia termica que no se usan en una planta de ciclo combinado pueden servir para operar el sistema de refrigeracion por absorcion. De esta manera, la energia termica requerida para el sistema de enfriamiento es gratuita. Con este sistema es posible incrementar la potencia de generacion de la turbina de gas de 5 a 25%.

  12. Power management system

    Science.gov (United States)

    Algrain, Marcelo C.; Johnson, Kris W.; Akasam, Sivaprasad; Hoff, Brian D.

    2007-10-02

    A method of managing power resources for an electrical system of a vehicle may include identifying enabled power sources from among a plurality of power sources in electrical communication with the electrical system and calculating a threshold power value for the enabled power sources. A total power load placed on the electrical system by one or more power consumers may be measured. If the total power load exceeds the threshold power value, then a determination may be made as to whether one or more additional power sources is available from among the plurality of power sources. At least one of the one or more additional power sources may be enabled, if available.

  13. South Carolina applications for industrial waste-heat recovery using heat pumps and Rankine-cycle power-generation systems

    Science.gov (United States)

    McCrosson, F. J.; Murray, K. A.

    1981-07-01

    The industries include: textile finishing, pulp and paper, noncellulosic fibers, pressed and blown glass, hydraulic cement, and secondary nonferrous metals. Thermodynamic and economic calculations determined system outputs and after-tax rates of return. The number of applications and net system outputs for the United States and for South Carolina were estimated.

  14. Predicting the ultimate potential of natural gas SOFC power cycles with CO2 capture - Part A: Methodology and reference cases

    Science.gov (United States)

    Campanari, Stefano; Mastropasqua, Luca; Gazzani, Matteo; Chiesa, Paolo; Romano, Matteo C.

    2016-08-01

    Driven by the search for the highest theoretical efficiency, in the latest years several studies investigated the integration of high temperature fuel cells in natural gas fired power plants, where fuel cells are integrated with simple or modified Brayton cycles and/or with additional bottoming cycles, and CO2 can be separated via chemical or physical separation, oxy-combustion and cryogenic methods. Focusing on Solid Oxide Fuel Cells (SOFC) and following a comprehensive review and analysis of possible plant configurations, this work investigates their theoretical potential efficiency and proposes two ultra-high efficiency plant configurations based on advanced intermediate-temperature SOFCs integrated with a steam turbine or gas turbine cycle. The SOFC works at atmospheric or pressurized conditions and the resulting power plant exceeds 78% LHV efficiency without CO2 capture (as discussed in part A of the work) and 70% LHV efficiency with substantial CO2 capture (part B). The power plants are simulated at the 100 MW scale with a complete set of realistic assumptions about fuel cell (FC) performance, plant components and auxiliaries, presenting detailed energy and material balances together with a second law analysis.

  15. Life Cycle Assessment of Coal-fired Power Production; TOPICAL

    International Nuclear Information System (INIS)

    Coal has the largest share of utility power generation in the US, accounting for approximately 56% of all utility-produced electricity (US DOE, 1998). Therefore, understanding the environmental implications of producing electricity from coal is an important component of any plan to reduce total emissions and resource consumption. A life cycle assessment (LCA) on the production of electricity from coal was performed in order to examine the environmental aspects of current and future pulverized coal boiler systems. Three systems were examined: (1) a plant that represents the average emissions and efficiency of currently operating coal-fired power plants in the US (this tells us about the status quo), (2) a new coal-fired power plant that meets the New Source Performance Standards (NSPS), and (3) a highly advanced coal-fired power plant utilizing a low emission boiler system (LEBS)

  16. The ISO 9001 combined cycle gas turbine power station

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, C. [Enron Power Operations Ltd., Middlesborough (United Kingdom)

    2000-07-01

    Enron Power Operations Limited is believed to be one of the first organisations to achieve BS EN ISO9001: 1994 for an Operational Combined Cycle Gas Turbine Power Station. In 1997 the Power Station decided to re-create policies and procedures to fill in the unknown gaps in its array of policies and procedures. The creation of the Quality Management System was expected to take six months utilising limited resources and the experiences of operational staff. Initial checks and internal audits created a wealth of information and highlighted some significant short falls, once certification was gained further issues have been noted. This paper concerns the development, implementation and certification of the Quality Management System at Teesside Power Station showing some benefits noted during this period and the short period after certification. Any other improvements and benefits will come in the future during continued development of the system. (author)

  17. High efficiency carbonate fuel cell/turbine hybrid power cycles

    Energy Technology Data Exchange (ETDEWEB)

    Steinfeld, G. [Energy Research Corp., Danbury, CT (United States)

    1995-10-19

    Carbonate fuel cells developed by Energy Research Corporation, in commercial 2.85 MW size, have an efficiency of 57.9 percent. Studies of higher efficiency hybrid power cycles were conducted in cooperation with METC to identify an economically competitive system with an efficiency in excess of 65 percent. A hybrid power cycle was identified that includes a direct carbonate fuel cell, a gas turbine and a steam cycle, which generates power at a LHV efficiency in excess of 70 percent. This new system is called a Tandem Technology Cycle (TTC). In a TTC operating on natural gas fuel, 95 percent of the fuel is mixed with recycled fuel cell anode exhaust, providing water for the reforming of the fuel, and flows to a direct carbonate fuel cell system which generates 72 percent of the power. The portion of the fuel cell anode exhaust which is not recycled, is burned and heat is transferred to the compressed air from a gas turbine, raising its temperature to 1800{degrees}F. The stream is then heated to 2000{degrees}F in the gas turbine burner and expands through the turbine generating 13 percent of the power. Half the exhaust from the gas turbine flows to the anode exhaust burner, and the remainder flows to the fuel cell cathodes providing the O{sub 2} and CO{sub 2} needed in the electrochemical reaction. Exhaust from the fuel cells flows to a steam system which includes a heat recovery steam generator and stages steam turbine which generates 15 percent of the TTC system power. Studies of the TTC for 200-MW and 20-MW size plants quantified performance, emissions and cost-of-electricity, and compared the characteristics of the TTC to gas turbine combined cycles. A 200-MW TTC plant has an efficiency of 72.6 percent, and is relatively insensitive to ambient temperature, but requires a heat exchanger capable of 2000{degrees}F. The estimated cost of electricity is 45.8 mills/kWhr which is not competitive with a combined cycle in installations where fuel cost is under $5.8/MMBtu.

  18. Power plant system assessment. Final report. SP-100 Program

    International Nuclear Information System (INIS)

    The purpose of this assessment was to provide system-level insights into 100-kWe-class space reactor electric systems. Using these insights, Rockwell was to select and perform conceptual design studies on a ''most attractive'' system that met the preliminary design goals and requirements of the SP-100 Program. About 4 of the 6 months were used in the selection process. The remaining 2 months were used for the system conceptual design studies. Rockwell completed these studies at the end of FY 1983. This report summarizes the results of the power plant system assessment and describes our choice for the most attractive system - the Rockwell SR-100G System (Space Reactor, 100 kWe, Growth) - a lithium-cooled UN-fueled fast reactor/Brayton turboelectric converter system

  19. Thermal analysis of heat storage canisters for a solar dynamic, space power system

    Science.gov (United States)

    Wichner, R. P.; Solomon, A. D.; Drake, J. B.; Williams, P. T.

    1988-01-01

    A thermal analysis was performed of a thermal energy storage canister of a type suggested for use in a solar receiver for an orbiting Brayton cycle power system. Energy storage for the eclipse portion of the cycle is provided by the latent heat of a eutectic mixture of LiF and CaF2 contained in the canister. The chief motivation for the study is the prediction of vapor void effects on temperature profiles and the identification of possible differences between ground test data and projected behavior in microgravity. The first phase of this study is based on a two-dimensional, cylindrical coordinates model using an interim procedure for describing void behavor in 1-g and microgravity. The thermal analysis includes the effects of solidification front behavior, conduction in liquid/solid salt and canister materials, void growth and shrinkage, radiant heat transfer across the void, and convection in the melt due to Marangoni-induced flow and, in 1-g, flow due to density gradients. A number of significant differences between 1-g and o-g behavior were found. This resulted from differences in void location relative to the maximum heat flux and a significantly smaller effective conductance in 0-g due to the absence of gravity-induced convection.

  20. Test results on parabolic dish concentrators for solar thermal power systems

    Science.gov (United States)

    Jaffe, Leonard D.

    1989-01-01

    This paper presents results of development testing of various solar thermal parabolic dish concentrators. The concentrators were mostly designed for the production of electric power using dish-mounted Rankine, Brayton or Stirling cycle engines, intended to be produced at low cost. Measured performance for various dishes included optical efficiencies ranging from 0.32 to 0.86 at a geometric concentration ratio of 500, and from about 0.09 to 0.85 at a geometric concentration ratio of 3000. Some malfunctions were observed. The tests should provide operating information of value in developing concentrators with improved performance and reduced maintenance.

  1. Solar powered Stirling cycle electrical generator

    Science.gov (United States)

    Shaltens, Richard K.

    1991-03-01

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

  2. Optimization of CCGT power plant and performance analysis using MATLAB/Simulink with actual operational data.

    Science.gov (United States)

    Hasan, Naimul; Rai, Jitendra Nath; Arora, Bharat Bhushan

    2014-01-01

    In the Modern scenario, the naturally available resources for power generation are being depleted at an alarming rate; firstly due to wastage of power at consumer end, secondly due to inefficiency of various power system components. A Combined Cycle Gas Turbine (CCGT) integrates two cycles- Brayton cycle (Gas Turbine) and Rankine cycle (Steam Turbine) with the objective of increasing overall plant efficiency. This is accomplished by utilising the exhaust of Gas Turbine through a waste-heat recovery boiler to run a Steam Turbine. The efficiency of a gas turbine which ranges from 28% to 33% can hence be raised to about 60% by recovering some of the low grade thermal energy from the exhaust gas for steam turbine process. This paper is a study for the modelling of CCGT and comparing it with actual operational data. The performance model for CCGT plant was developed in MATLAB/Simulink. PMID:24936394

  3. Monitoring strategies for a combined cycle electric power generator

    International Nuclear Information System (INIS)

    Electric power generation systems require continuous monitoring to ensure safe and reliable operation. The data available from plant sensors supplied to the control systems may also be analyzed to verify proper operation and predict future behavior. In this paper, a combined cycle electric power plant has been monitored using limit and trend checking, reconstructed phase planes, and regression curves for transient and steady-state power generation. Representative experimental results are presented and discussed to illustrate the strengths of the proposed analysis strategies on a 510 MW combined-cycle system and a 180 MW steam turbine. The phase space analysis provides a means of visual inspection of operational anomalies and also offers a context for numerical analysis of the anomalous behavior. The statistical prognostic method provided regression errors below 2.0% for two of the three proposed plant signal combinations. However, all signal combinations offered the opportunity for system monitoring and diagnosis in terms of threshold violations which varied from 2.7% to 5.4% for these two signal sets. Overall, the monitoring strategies exhibited great promise for power generation system applications and merit further study.

  4. Development of cooling system for 66/6.9kV-20MVA REBCO superconducting transformers with Ne turbo-Brayton refrigerator and subcooled liquid nitrogen

    Science.gov (United States)

    Iwakuma, M.; Adachi, K.; Yun, K.; Yoshida, K.; Sato, S.; Suzuki, Y.; Umeno, T.; Konno, M.; Hayashi, H.; Eguchi, T.; Izumi, T.; Shiohara, Y.

    2015-12-01

    We developed a turbo-Brayton refrigerator with Ne gas as a working fluid for a 3 ϕ- 66/6.9kV-2MVA superconducting transformer with coated conductors which was bath-cooled with subcooled LN2. The two-stage compressor and expansion turbine had non-contact magnetic bearings for a long maintenance interval. In the future, we intend to directly install a heat exchanger into the Glass-Fiber-Reinforced-Plastics cryostat of a transformer and make a heat exchange between the working fluid gas and subcooled LN2. In this paper we investigate the behaviour of subcooled LN2 in a test cryostat, in which heater coils were arranged side by side with a flat plate finned-tube heat exchanger. Here a He turbo-Brayton refrigerator was used as a substitute for a Ne turbo-Brayton one. The pressure at the surface of LN2 in the cryostat was one atmosphere. Just under the LN2 surface, a stationary layer of LN2 was created over the depth of 20 cm and temperature dropped from 77 K to 65 K with depth while, in the lower level than that, a natural convection flow of LN2 was formed and temperature was almost uniform over 1 m depth. The boundary plane between the stationary layer and the natural convection region was visible.

  5. Technical comparison between Integrated Gasification Combined Cycle (IGCC) and Natural Gas Combined Cycle (NGCC) power plants

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Pablo Andres Silva; Venturini, Osvaldo Jose; Lora, Electo Eduardo Silva [Federal University of Itajuba - UNIFEI, MG (Brazil). Excellence Group in Thermal Power and Distributed Generation - NEST], e-mails: osvaldo@unifei.edu.br, electo@unifei.edu.br

    2010-07-01

    Among the emerging clean coal technologies for power generation, Integrated Gasification Combined Cycle (IGCC) and Natural Gas Combined Cycle (NGCC) systems are receiving considerable attention as a potentially attractive option to reduce the emissions of greenhouse gases (GHG). The main reason is because these systems has high efficiency and low emissions in comparison with traditional power generation plants. Currently in IGCC and NGCC systems at demonstration stage is been considered to implement CCS technology. CO{sub 2} emissions can be avoided in a gasification-based power plant because by transferring almost all carbon compounds to CO{sub 2} through the water gas shift (WGS) reaction, then removing the CO{sub 2} before it is diluted in the combustion stage. The aim of this study is to compare the technical performance of an IGCC system that uses Brazilian coal and petroleum coke as fuel with a NGCC system, with the same fixed output power of 450 MW. The first section of this paper presents the plant configurations of IGCC systems. The following section presents an analysis of NGCC technology. (author)

  6. Optimization of Biomass-Fuelled Combined Cooling, Heating and Power (CCHP Systems Integrated with Subcritical or Transcritical Organic Rankine Cycles (ORCs

    Directory of Open Access Journals (Sweden)

    Daniel Maraver

    2014-04-01

    Full Text Available This work is focused on the thermodynamic optimization of Organic Rankine Cycles (ORCs, coupled with absorption or adsorption cooling units, for combined cooling heating and power (CCHP generation from biomass combustion. Results were obtained by modelling with the main aim of providing optimization guidelines for the operating conditions of these types of systems, specifically the subcritical or transcritical ORC, when integrated in a CCHP system to supply typical heating and cooling demands in the tertiary sector. The thermodynamic approach was complemented, to avoid its possible limitations, by the technological constraints of the expander, the heat exchangers and the pump of the ORC. The working fluids considered are: n-pentane, n-heptane, octamethyltrisiloxane, toluene and dodecamethylcyclohexasiloxane. In addition, the energy and environmental performance of the different optimal CCHP plants was investigated. The optimal plant from the energy and environmental point of view is the one integrated by a toluene recuperative ORC, although it is limited to a development with a turbine type expander. Also, the trigeneration plant could be developed in an energy and environmental efficient way with an n-pentane recuperative ORC and a volumetric type expander.

  7. Improving geothermal power plants with a binary cycle

    Science.gov (United States)

    Tomarov, G. V.; Shipkov, A. A.; Sorokina, E. V.

    2015-12-01

    The recent development of binary geothermal technology is analyzed. General trends in the introduction of low-temperature geothermal sources are summarized. The use of single-phase low-temperature geothermal fluids in binary power plants proves possible and expedient. The benefits of power plants with a binary cycle in comparison with traditional systems are shown. The selection of the working fluid is considered, and the influence of the fluid's physicochemical properties on the design of the binary power plant is discussed. The design of binary power plants is based on the chemical composition and energy potential of the geothermal fluids and on the landscape and climatic conditions at the intended location. Experience in developing a prototype 2.5 MW Russian binary power unit at Pauzhetka geothermal power plant (Kamchatka) is outlined. Most binary systems are designed individually for a specific location. Means of improving the technology and equipment at binary geothermal power plants are identified. One option is the development of modular systems based on several binary systems that employ the heat from the working fluid at different temperatures.

  8. Politics of nuclear power and fuel cycle

    International Nuclear Information System (INIS)

    -is likely to remain evolving depending on regional and global affairs. Opposition or support for nuclear technology is also likely to be a function of regional and global politics. In response to such pressures, IAEA is organizing a workshop of 140 countries to discuss proposals to guarantee countries' supply of nuclear fuel (September 19-21-, 2006; Vienna). Premise and Question: A single nuclear power plant in a country may be good for the prestige of the country, but such units are unlikely to make a major impact on the energy scene. Hence, in order for nuclear power to play a significant role, countries that decide to 'go nuclear,' would most likely want to diversify a significant fraction of their electricity generating capacity (and possibly heating and, in the future, hydrogen production) to nuclear, possibly requiring at least few and possibly many nuclear power plants. In order to proceed with the nuclear option, these countries would expect a certain level of long term assurance on the fuel supply. What is the kind of options that would satisfy the needs of these countries and at the same time addressing the non-proliferation concerns? Options: The options available to countries for their nuclear program can be categorized as follows. A. Fully indigenous program with complete development of power plants and fuel cycle. B. Fully or partly indigenous program for power plant development; while depending on international consortium for fuel supply and waste treatment. C. Rely on international consortia to build and operate all aspects of nuclear power plants (with local manpower). Others: A total of around fifty to seventy five countries are likely to be interested in nuclear power in the next fifty years. These can be divided in to the three groups (A-C) given above. It is likely that, with time, there will be some expectation to move to higher levels (C to B and B to A). Countries already in group A and those willing to start in group C do not pose an issue. It is

  9. Fiscal 1995 survey of promotion of the geothermal development. Report on a usage feasibility test of a small scale geothermal binary cycle power generation system; 1995 nendo chinetsu kaihatsu sokushin chosa. Chusho chinetsu binary hatsuden system jissho shiken hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    In this survey, studies for popularization and practical utilization of small and medium size geothermal binary cycle power systems which assesses low and medium temperature geothermal resources were conducted, and studies for development of the system to be introduced for practical use and for promotion of the popularization were made. A study was carried out of preconditions and various conditions of a demonstrative test plant (100kW class, 500kW class) in view of the initial cost of the actual plant, and an analysis was made of the power generation cost. Acceptability of the demonstrative test plant (100kW class) was examined to analyze problems on the introduction. A thermodynamic analysis was made of the output of geothermal binary cycle power generation. Analysis/evaluation of the results of the 100kW demonstrative test plant were carried out in view of the operation results of the plant of the same kind, and checks/reviews were conducted of performance and reliability of the system, equipment simplification, etc. Inspection of the system was made in the stage of design/manufacture of the 500kW demonstrative test plant. Concerning the spread/expansion of the system, studied were multiple stage geothermal utilization and PR promotion method. 14 refs., 62 figs., 55 tabs.

  10. Solar thermal power system

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Charles L.

    2010-06-15

    A solar thermal power generator includes an inclined elongated boiler tube positioned in the focus of a solar concentrator for generating steam from water. The boiler tube is connected at one end to receive water from a pressure vessel as well as connected at an opposite end to return steam back to the vessel in a fluidic circuit arrangement that stores energy in the form of heated water in the pressure vessel. An expander, condenser, and reservoir are also connected in series to respectively produce work using the steam passed either directly (above a water line in the vessel) or indirectly (below a water line in the vessel) through the pressure vessel, condense the expanded steam, and collect the condensed water. The reservoir also supplies the collected water back to the pressure vessel at the end of a diurnal cycle when the vessel is sufficiently depressurized, so that the system is reset to repeat the cycle the following day. The circuital arrangement of the boiler tube and the pressure vessel operates to dampen flow instabilities in the boiler tube, damp out the effects of solar transients, and provide thermal energy storage which enables time shifting of power generation to better align with the higher demand for energy during peak energy usage periods.

  11. Output power analyses for the thermodynamic cycles of thermal power plants

    International Nuclear Information System (INIS)

    Thermal power plant is one of the important thermodynamic devices, which is very common in all kinds of power generation systems. In this paper, we use a new concept, entransy loss, as well as exergy destruction, to analyze the single reheating Rankine cycle unit and the single stage steam extraction regenerative Rankine cycle unit in power plants. This is the first time that the concept of entransy loss is applied to the analysis of the power plant Rankine cycles with reheating and steam extraction regeneration. In order to obtain the maximum output power, the operating conditions under variant vapor mass flow rates are optimized numerically, as well as the combustion temperatures and the off-design flow rates of the flue gas. The relationship between the output power and the exergy destruction rate and that between the output power and the entransy loss rate are discussed. It is found that both the minimum exergy destruction rate and the maximum entransy loss rate lead to the maximum output power when the combustion temperature and heat capacity flow rate of the flue gas are prescribed. Unlike the minimum exergy destruction rate, the maximum entransy loss rate is related to the maximum output power when the highest temperature and heat capacity flow rate of the flue gas are not prescribed. (general)

  12. Nuclear proliferation and civilian nuclear power. Report of the Nonproliferation Alternative Systems Assessment Program. Volume IX. Reactor and fuel cycle description

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    The Nonproliferation Alterntive Systems Assessment Program (NASAP) has characterized and assessed various reactor/fuel-cycle systems. Volume IX provides, in summary form, the technical descriptions of the reactor/fuel-cycle systems studied. This includes the status of the system technology, as well as a discussion of the safety, environmental, and licensing needs from a technical perspective. This information was then used in developing the research, development, and demonstration (RD and D) program, including its cost and time frame, to advance the existing technology to the level needed for commercial use. Wherever possible, the cost data are given as ranges to reflect the uncertainties in the estimates.

  13. Nuclear proliferation and civilian nuclear power. Report of the Nonproliferation Alternative Systems Assessment Program. Volume IX. Reactor and fuel cycle description

    International Nuclear Information System (INIS)

    The Nonproliferation Alterntive Systems Assessment Program (NASAP) has characterized and assessed various reactor/fuel-cycle systems. Volume IX provides, in summary form, the technical descriptions of the reactor/fuel-cycle systems studied. This includes the status of the system technology, as well as a discussion of the safety, environmental, and licensing needs from a technical perspective. This information was then used in developing the research, development, and demonstration (RD and D) program, including its cost and time frame, to advance the existing technology to the level needed for commercial use. Wherever possible, the cost data are given as ranges to reflect the uncertainties in the estimates

  14. The cost of fuel cycle and competitiveness of nuclear power

    International Nuclear Information System (INIS)

    The current price of nuclear fuel is rising and changing in international market, which influences the cost and development of nuclear power in China. This thesis suggests a plan to control the cost of the whole fuel cycle, to improve the competitiveness of nuclear power in China, to accelerate the development of both fuel cycle and nuclear power industries. (authors)

  15. Organic flash cycles for efficient power production

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Tony; Mao, Samuel S.; Greif, Ralph

    2016-03-15

    This disclosure provides systems, methods, and apparatus related to an Organic Flash Cycle (OFC). In one aspect, a modified OFC system includes a pump, a heat exchanger, a flash evaporator, a high pressure turbine, a throttling valve, a mixer, a low pressure turbine, and a condenser. The heat exchanger is coupled to an outlet of the pump. The flash evaporator is coupled to an outlet of the heat exchanger. The high pressure turbine is coupled to a vapor outlet of the flash evaporator. The throttling valve is coupled to a liquid outlet of the flash evaporator. The mixer is coupled to an outlet of the throttling valve and to an outlet of the high pressure turbine. The low pressure turbine is coupled to an outlet of the mixer. The condenser is coupled to an outlet of the low pressure turbine and to an inlet of the pump.

  16. Nuclear proliferation and civilian nuclear power. Report of the Nonproliferation Alternative Systems Assessment Program. Volume III. Resources and fuel cycle facilities

    International Nuclear Information System (INIS)

    The ability of uranium supply and the rest of the nuclear fuel cycle to meet the demand for nuclear power is an important consideration in future domestic and international planning. Accordingly, the purpose of this assessment is to evaluate the adequacy of potential supply for various nuclear resources and fuel cycle facilities in the United States and in the world outside centrally planned economy areas (WOCA). Although major emphasis was placed on uranium supply and demand, material resources (thorium and heavy water) and facility resources (separative work, spent fuel storage, and reprocessing) were also considered

  17. Optimizing design of converters using power cycling lifetime models

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Ørndrup; Munk-Nielsen, Stig

    2015-01-01

    Converter power cycling lifetime depends heavily on converter operation point. A lifetime model of a single power module switched mode power supply with wide input voltage range is shown. A lifetime model is created using a power loss model, a thermal model and a model for power cycling capability...... with a given mission profile. A method to improve the expected lifetime of the converter is presented, taking into account switching frequency, input voltage and transformer turns ratio....

  18. Power Cycle Testing of Press-Pack IGBT Chips

    OpenAIRE

    Frank, Øyvind Bjerke

    2014-01-01

    In this thesis the power cycling capability of individual press-pack IGBT chips is investigated. Press-pack is a packaging technology used for power semiconductors. For press-packs, both thermal and electrical contact to the semiconductor chip is obtained by the application of force on the package. Press-pack IGBTs is claimed by the manufacturers to be especially suitable for high-power applications with large variations in power output. Power cycle testing is an accelerated lifetime stress t...

  19. Advanced power cycles with mixture as the working fluid

    OpenAIRE

    Jonsson, Maria

    2003-01-01

    The world demand for electrical power increasescontinuously, requiring efficient and low-cost methods forpower generation. This thesis investigates two advanced powercycles with mixtures as the working fluid: the Kalina cycle,alternatively called the ammonia-water cycle, and theevaporative gas turbine cycle. These cycles have the potentialof improved performance regarding electrical efficiency,specific power output, specific investment cost and cost ofelectricity compared with the conventiona...

  20. Flight experiment of thermal energy storage. [for spacecraft power systems

    Science.gov (United States)

    Namkoong, David

    1989-01-01

    Thermal energy storage (TES) enables a solar dynamic system to deliver constant electric power through periods of sun and shade. Brayton and Stirling power systems under current considerations for missions in the near future require working fluid temperatures in the 1100 to 1300+ K range. TES materials that meet these requirements fall into the fluoride family of salts. Salts shrink as they solidify, a change reaching 30 percent for some salts. Hot spots can develop in the TES container or the container can become distorted if the melting salt cannot expand elsewhere. Analysis of the transient, two-phase phenomenon is being incorporated into a three-dimensional computer code. The objective of the flight program is to verify the predictions of the code, particularly of the void location and its effect on containment temperature. The four experimental packages comprising the program will be the first tests of melting and freezing conducted under microgravity.

  1. Model Predictive Control of Integrated Gasification Combined Cycle Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    B. Wayne Bequette; Priyadarshi Mahapatra

    2010-08-31

    The primary project objectives were to understand how the process design of an integrated gasification combined cycle (IGCC) power plant affects the dynamic operability and controllability of the process. Steady-state and dynamic simulation models were developed to predict the process behavior during typical transients that occur in plant operation. Advanced control strategies were developed to improve the ability of the process to follow changes in the power load demand, and to improve performance during transitions between power levels. Another objective of the proposed work was to educate graduate and undergraduate students in the application of process systems and control to coal technology. Educational materials were developed for use in engineering courses to further broaden this exposure to many students. ASPENTECH software was used to perform steady-state and dynamic simulations of an IGCC power plant. Linear systems analysis techniques were used to assess the steady-state and dynamic operability of the power plant under various plant operating conditions. Model predictive control (MPC) strategies were developed to improve the dynamic operation of the power plants. MATLAB and SIMULINK software were used for systems analysis and control system design, and the SIMULINK functionality in ASPEN DYNAMICS was used to test the control strategies on the simulated process. Project funds were used to support a Ph.D. student to receive education and training in coal technology and the application of modeling and simulation techniques.

  2. Study on the matching performance of a low temperature reverse Brayton air refrigerator

    International Nuclear Information System (INIS)

    Highlights: • A relation between operation parameters of expander and brake pressure was obtained. • A matching model was got based on the theoretical analysis and simulation. • Brake pressure feedback control was proposed and applied in the experiment. • The minimum free-load refrigerating temperature of 99.6 K was reached. - Abstract: A small reverse Brayton cycle air refrigerator was designed and fabricated. Bump-type air journal foil bearing, pressurized thrust gas bearing and centrifugal blower as brake were employed in the turboexpander. Usually, constant brake inlet pressure is set in a reverse Brayton refrigerator. However, the unchanged brake inlet pressure cannot adapt to the changing temperature and expansion ratio during the cooling down process, which could go against the system performance. In this article, the relationship between the turboexpander operation parameters and brake pressure was disclosed through theoretical analysis. The performance curve was analyzed through numerical simulation using CFX. A matching model was established based on the theoretical analysis and numerical simulation. Brake pressure feedback control was then proposed and applied in the experimental study. Thermal performance of the refrigerator was tested under varied operating conditions (different expansion ratios, temperatures and brake pressures). The results indicated that the appropriate brake pressure facilitated system good thermal performance under both design and off-design conditions, and the theoretical results agreed well with the experimental data

  3. Analysis of shadowing effects on MIR photovoltaic and solar dynamic power systems

    Science.gov (United States)

    Fincannon, James

    1995-01-01

    The NASA Lewis Research Center is currently working with RSC-Energia, the Russian Space Agency, and Allied Signal in developing a flight demonstration solar dynamic power system. This type of power system is dependent upon solar flux that is reflected and concentrated into a thermal storage system to provide the thermal energy input to a closed-cycle Brayton heat engine. The solar dynamic unit will be flown on the Russian Mir space station in anticipation of use on the International Space Station Alpha. By the time the power system is launched, the Mir will be a spatially complex configuration which will have, in addition to the three-gimbaled solar dynamic unit, eleven solar array wings that are either fixed or track the Sun along one axis and a variety or repositionable habitation and experiment modules. The proximity of arrays to modules creates a situation which makes it highly probable that there will be varying solar flux due to shadowing on the solar dynamic unit and some of the arrays throughout the orbit. Shadowing causes fluctuations in the power output from the arrays and the solar dynamic power system, thus reducing the energy capabilities of the spacecraft. An assessment of the capabilities of the power system under these conditions is an important part in influencing the design and operations of the spacecraft and predicting its energy performance. This paper describes the results obtained from using the Orbiting Spacecraft Shadowing Analysis Station program that was integrated into the Station Power Analysis for Capability Evaluation (SPACE) electrical power system computer program. OSSA allows one to consider the numerous complex factors for analyzing the shadowing effects on the electrical power system including the variety of spacecraft hardware geometric configurations, yearly and daily orbital variations in the vehicle attitude and orbital maneuvers (for communications coverage, payload pointing requirements and rendezvous/docking with other

  4. Supercritical CO2 direct cycle Gas Fast Reactor (SC-GFR) concept.

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Steven Alan; Parma, Edward J., Jr.; Suo-Anttila, Ahti Jorma (Computational Engineering Analysis, Albuquerque, NM); Al Rashdan, Ahmad (Texas A& M University, College Station, TX); Tsvetkov, Pavel Valeryevich (Texas A& M University, College Station, TX); Vernon, Milton E.; Fleming, Darryn D.; Rochau, Gary Eugene

    2011-05-01

    This report describes the supercritical carbon dioxide (S-CO{sub 2}) direct cycle gas fast reactor (SC-GFR) concept. The SC-GFR reactor concept was developed to determine the feasibility of a right size reactor (RSR) type concept using S-CO{sub 2} as the working fluid in a direct cycle fast reactor. Scoping analyses were performed for a 200 to 400 MWth reactor and an S-CO{sub 2} Brayton cycle. Although a significant amount of work is still required, this type of reactor concept maintains some potentially significant advantages over ideal gas-cooled systems and liquid metal-cooled systems. The analyses presented in this report show that a relatively small long-life reactor core could be developed that maintains decay heat removal by natural circulation. The concept is based largely on the Advanced Gas Reactor (AGR) commercial power plants operated in the United Kingdom and other GFR concepts.

  5. Electric power systems

    CERN Document Server

    Weedy, B M; Jenkins, N; Ekanayake, J B; Strbac, G

    2012-01-01

    The definitive textbook for Power Systems students, providing a grounding in essential power system theory while also focusing on practical power engineering applications. Electric Power Systems has been an essential book in power systems engineering for over thirty years. Bringing the content firmly up-to-date whilst still retaining the flavour of Weedy's extremely popular original, this Fifth Edition has been revised by experts Nick Jenkins, Janaka Ekanayake and Goran Strbac. This wide-ranging text still covers all of the fundamental power systems subjects but is now e

  6. Nuclear proliferation and civilian nuclear power: report of the Nonproliferation Alternative Systems Assessment Program. Volume IX. Reactor and fuel cycle descriptions

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    The Nonproliferation Alternative Systems Assessment Program (NASAP) has characterized and assessed various reactor/fuel-cycle systems. Volume IX provides, in summary form, the technical descriptions of the reactor/fuel-cycle systems studied. This includes the status of the system technology, as well as a discussion of the safety, environmental, and licensing needs from a technical perspective. This information was then used in developing the research, development, and demonstration (RD and D) program, including its cost and time frame, to advance the existing technology to the level needed for commercial use. Wherever possible, the cost data are given as ranges to reflect the uncertainties in the estimates. Volume IX is divided into three sections: Chapter 1, Reactor Systems; Chapter 2, Fuel-Cycle Systems; and the Appendixes. Chapter 1 contains the characterizations of the following 12 reactor types: light-water reactor; heavy-water reactor; water-cooled breeder reactor; high-temperature gas-cooled reactor; gas-cooled fast reactor; liquid-metal fast breeder reactor; spectral-shift-controlled reactor; accelerator-driven reactor; molten-salt reactor; gaseous-core reactor; tokamak fusion-fisson hybrid reactor; and fast mixed-spectrum reactor. Chapter 2 contains similar information developed for fuel-cycle facilities in the following categories: mining and milling; conversion and enrichment; fuel fabrication; spent fuel reprocessing; waste handling and disposal; and transportation of nuclear materials.

  7. Nuclear proliferation and civilian nuclear power: report of the Nonproliferation Alternative Systems Assessment Program. Volume IX. Reactor and fuel cycle descriptions

    International Nuclear Information System (INIS)

    The Nonproliferation Alternative Systems Assessment Program (NASAP) has characterized and assessed various reactor/fuel-cycle systems. Volume IX provides, in summary form, the technical descriptions of the reactor/fuel-cycle systems studied. This includes the status of the system technology, as well as a discussion of the safety, environmental, and licensing needs from a technical perspective. This information was then used in developing the research, development, and demonstration (RD and D) program, including its cost and time frame, to advance the existing technology to the level needed for commercial use. Wherever possible, the cost data are given as ranges to reflect the uncertainties in the estimates. Volume IX is divided into three sections: Chapter 1, Reactor Systems; Chapter 2, Fuel-Cycle Systems; and the Appendixes. Chapter 1 contains the characterizations of the following 12 reactor types: light-water reactor; heavy-water reactor; water-cooled breeder reactor; high-temperature gas-cooled reactor; gas-cooled fast reactor; liquid-metal fast breeder reactor; spectral-shift-controlled reactor; accelerator-driven reactor; molten-salt reactor; gaseous-core reactor; tokamak fusion-fisson hybrid reactor; and fast mixed-spectrum reactor. Chapter 2 contains similar information developed for fuel-cycle facilities in the following categories: mining and milling; conversion and enrichment; fuel fabrication; spent fuel reprocessing; waste handling and disposal; and transportation of nuclear materials

  8. Energy analysis of nuclear power plants and their fuel cycle

    International Nuclear Information System (INIS)

    Energy analysis has become an increasingly feasible and practical additional method for evaluating the engineering, economic and environmental aspects of power-producing systems. It compares total direct and indirect energy investment into construction and operation of power plants with their lifetime energy output. This method was applied to nuclear power-producing systems and their fuel cycles. Results were adapted to countries with various levels of industrialization and resources. With dynamic energy analysis different scenarios were investigated. For comparison purposes fossil-fuelled and solar power plants were analysed. The global results of static evaluation analysis were specifically modified according to the economic situations of countries with various levels of industrialization. The influence of energy imports upon energy analysis is also discussed. By dynamic energy analyses the cumulative energy requirements for specific power plant construction programmes have been compared with their total energy output. Investigations of this sort are extremely valuable not only for economic reasons, but especially for their usefulness in showing the advantages and disadvantages of a specific power programme with respect to its alternatives. Naturally the impact of these investigations on the fuel requirements is of importance, especially because of the frequently cited ''valuable cumulated fossil fuel savings''. (author)

  9. Parametric analysis for a new combined power and ejector-absorption refrigeration cycle

    International Nuclear Information System (INIS)

    A new combined power and ejector-absorption refrigeration cycle is proposed, which combines the Rankine cycle and the ejector-absorption refrigeration cycle, and could produce both power output and refrigeration output simultaneously. This combined cycle, which originates from the cycle proposed by authors previously, introduces an ejector between the rectifier and the condenser, and provides a performance improvement without greatly increasing the complexity of the system. A parametric analysis is conducted to evaluate the effects of the key thermodynamic parameters on the cycle performance. It is shown that heat source temperature, condenser temperature, evaporator temperature, turbine inlet pressure, turbine inlet temperature, and basic solution ammonia concentration have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. It is evident that the ejector can improve the performance of the combined cycle proposed by authors previously.

  10. Junction temperature estimation for an advanced active power cycling test

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede; Jørgensen, S.

    estimation method using on-state VCE for an advanced active power cycling test is proposed. The concept of the advanced power cycling test is explained first. Afterwards the junction temperature estimation method using on-state VCE and current is presented. Further, the method to improve the accuracy of the...

  11. Combined cycle gas turbine for thermal power stations: experience in designing and operation, prospects in application

    OpenAIRE

    N. V. Karnitsky; E. A. Matveev

    2014-01-01

    The paper has reviewed main world tendencies in power consumption and power system structure. Main schemes of combined cycle gas turbines have been considered in the paper. The paper contains an operational analysis of CCGT blocks that are operating within the Belarusian energy system. The analysis results have been given in tables showing main operational indices of power blocks

  12. COMBINED CYCLE GAS TURBINE FOR THERMAL POWER STATIONS: EXPERIENCE IN DESIGNING AND OPERATION, PROSPECTS IN APPLICATION

    Directory of Open Access Journals (Sweden)

    N. V. Karnitsky

    2015-01-01

    Full Text Available The paper has reviewed main world tendencies in power consumption and power system structure. Main schemes of combined cycle gas turbines have been considered in the paper. The paper contains an operational analysis of CCGT blocks that are operating within the Belarusian energy system. The analysis results have been given in tables showing main operational indices of power blocks

  13. Hybrid solar central receiver for combined cycle power plant

    Energy Technology Data Exchange (ETDEWEB)

    Bharathan, Desikan (Lakewood, CO); Bohn, Mark S. (Golden, CO); Williams, Thomas A. (Arvada, CO)

    1995-01-01

    A hybrid combined cycle power plant including a solar central receiver for receiving solar radiation and converting it to thermal energy. The power plant includes a molten salt heat transfer medium for transferring the thermal energy to an air heater. The air heater uses the thermal energy to preheat the air from the compressor of the gas cycle. The exhaust gases from the gas cycle are directed to a steam turbine for additional energy production.

  14. Hybrid solar central receiver for combined cycle power plant