Modeling and simulation of syngas purification and power generation in integrated gasification combined cycle (IGCS)

International Nuclear Information System (INIS)

Mehmood, N.; Zaman, Z.U.; Mehran, M.T.

2011-01-01

Integrated Gasification Combined Cycle (IGCC) is one of the most promising technologies for power generation; The environmental benefits and the higher energy conversion efficiency distinguish it from traditional coal generation technologies. This work presents a structured and validated conceptual model of purification of coal gas produced during the Underground Coal Gasification (UCG) of coal containing high sulfur contents. Gas cleaning operations for CO/sub 2/, H/sub 2/S and moisture removal have been modeled in steady and dynamic state. The power generation from combined cycle is also modeled. The model has been developed using Aspen HYSYS and Aspen Plus simulation software. Predicted results of clean gas composition and generated power present a good agreement with industrial data and efficiency parameters. This study is aimed at obtaining optimal assessment of an integrated gasification combined cycle (IGCC) power plant configurations. (author)

Analysis of a novel solar energy-powered Rankine cycle for combined power and heat generation using supercritical carbon dioxide

Energy Technology Data Exchange (ETDEWEB)

Zhang, X.R.; Yamaguchi, H.; Uneno, D. [Department of Mechanical Engineering, Doshisha University, Kyoto 630-0321 (Japan); Fujima, K. [Mayekawa MFG Co., Ltd., 2000 Tatsuzawa Moriya-city, Ibaraki-Pref. 302-0118 (Japan); Enomoto, M. [Showa Denko K. K., 1-480, Inuzuka, Oyama-city, Tochigi 323-8679 (Japan); Sawada, N. [Showa Tansan Co., Ltd., 7-1, Ogimachi, Kawasaki-Ku, Kawasaki-city, Kanagawa 210-0867 (Japan)

2006-10-15

Theoretical analysis of a solar energy-powered Rankine thermodynamic cycle utilizing an innovative new concept, which uses supercritical carbon dioxide as a working fluid, is presented. In this system, a truly 'natural' working fluid, carbon dioxide, is utilized to generate firstly electricity power and secondly high-grade heat power and low-grade heat power. The uniqueness of the system is in the way in which both solar energy and carbon dioxide, available in abundant quantities in all parts of the world, are simultaneously used to build up a thermodynamic cycle and has the potential to reduce energy shortage and greatly reduce carbon dioxide emissions and global warming, offering environmental and personal safety simultaneously. The system consists of an evacuated solar collector system, a power-generating turbine, a high-grade heat recovery system, a low-grade heat recovery system and a feed pump. The performances of this CO{sub 2}-based Rankine cycle were theoretically investigated and the effects of various design conditions, namely, solar radiation, solar collector area and CO{sub 2} flow rate, were studied. Numerical simulations show that the proposed system may have electricity power efficiency and heat power efficiency as high as 11.4% and 36.2%, respectively. It is also found that the cycle performances strongly depend on climate conditions. Also the electricity power and heat power outputs increase with the collector area and CO{sub 2} flow rate. The estimated COP{sub power} and COP{sub heat} increase with the CO{sub 2} flow rate, but decrease with the collector area. The CO{sub 2}-based cycle can be optimized to provide maximum power, maximum heat recovery or a combination of both. The results suggest the potential of this new concept for applications to electricity power and heat power generation. (author)

Optimizing power plant cycling operations while reducing generating plant damage and costs

Energy Technology Data Exchange (ETDEWEB)

Lefton, S A; Besuner, P H; Grimsrud, P [Aptech Engineering Services, Inc., Sunnyvale, CA (United States); Bissel, A [Electric Supply Board, Dublin (Ireland)

1999-12-31

This presentation describes a method for analyzing, quantifying, and minimizing the total cost of fossil, combined cycle, and pumped hydro power plant cycling operation. The method has been developed, refined, and applied during engineering studies at some 160 units in the United States and 8 units at the Irish Electric Supply Board (ESB) generating system. The basic premise of these studies was that utilities are underestimating the cost of cycling operation. The studies showed that the cost of cycling conventional boiler/turbine fossil power plants can range from between $2,500 and $500,000 per start-stop cycle. It was found that utilities typically estimate these costs by factors of 3 to 30 below actual costs and, thus, often significantly underestimate their true cycling costs. Knowledge of the actual, or total, cost of cycling will reduce power production costs by enabling utilities to more accurately dispatch their units to manage unit life expectancies, maintenance strategies and reliability. Utility management responses to these costs are presented and utility cost savings have been demonstrated. (orig.) 7 refs.

Optimizing power plant cycling operations while reducing generating plant damage and costs

Energy Technology Data Exchange (ETDEWEB)

Lefton, S.A.; Besuner, P.H.; Grimsrud, P. [Aptech Engineering Services, Inc., Sunnyvale, CA (United States); Bissel, A. [Electric Supply Board, Dublin (Ireland)

1998-12-31

This presentation describes a method for analyzing, quantifying, and minimizing the total cost of fossil, combined cycle, and pumped hydro power plant cycling operation. The method has been developed, refined, and applied during engineering studies at some 160 units in the United States and 8 units at the Irish Electric Supply Board (ESB) generating system. The basic premise of these studies was that utilities are underestimating the cost of cycling operation. The studies showed that the cost of cycling conventional boiler/turbine fossil power plants can range from between $2,500 and $500,000 per start-stop cycle. It was found that utilities typically estimate these costs by factors of 3 to 30 below actual costs and, thus, often significantly underestimate their true cycling costs. Knowledge of the actual, or total, cost of cycling will reduce power production costs by enabling utilities to more accurately dispatch their units to manage unit life expectancies, maintenance strategies and reliability. Utility management responses to these costs are presented and utility cost savings have been demonstrated. (orig.) 7 refs.

Extension of cycle 8 of Angra-1 reactor, optimization of electric power generation reduction

International Nuclear Information System (INIS)

Miranda, Anselmo Ferreira; Moreira, Francisco Jose; Valladares, Gastao Lommez

2000-01-01

The main objective of extending fuel cycle length of Angra-1 reactor, is in fact of that each normal refueling are changed about 40 fuel elements of the reactor core. Considering that these elements do not return for the reactor core, this procedure has became possible a more gain of energy of these elements. The extension consists in, after power generation corresponding to a cycle burnup of 13700 MWD/TMU or 363.3 days, to use the reactivity gain by reduction of power and temperature of primary system for power generation in a low energy patamar

Energy Balance of Nuclear Power Generation. Life Cycle Analyses of Nuclear Power

International Nuclear Information System (INIS)

Wallner, A.; Wenisch, A.; Baumann, M.; Renner, S.

2011-01-01

The accident at the Japanese nuclear power plant Fukushima in March 2011 triggered a debate about phasing out nuclear energy and the safety of nuclear power plants. Several states are preparing to end nuclear power generation. At the same time the operational life time of many nuclear power plants is reaching its end. Governments and utilities now need to take a decision to replace old nuclear power plants or to use other energy sources. In particular the requirement of reducing greenhouse gas emissions (GHG) is used as an argument for a higher share of nuclear energy. To assess the contribution of nuclear power to climate protection, the complete life cycle needs to be taken into account. Some process steps are connected to high CO2 emissions due to the energy used. While the processes before and after conventional fossil-fuel power stations can contribute up to 25% of direct GHG emission, it is up to 90 % for nuclear power (Weisser 2007). This report aims to produce information about the energy balance of nuclear energy production during its life cycle. The following key issues were examined: How will the forecasted decreasing uranium ore grades influence energy intensity and greenhouse emissions and from which ore grade on will no energy be gained anymore? In which range can nuclear energy deliver excess energy and how high are greenhouse gas emissions? Which factors including ore grade have the strongest impact on excess energy? (author)

Life cycle assessment of rice straw-based power generation in Malaysia

International Nuclear Information System (INIS)

Shafie, S.M.; Masjuki, H.H.; Mahlia, T.M.I.

2014-01-01

This paper presents an application of LCA (Life Cycle Assessment) with a view to analyzing the environment aspects of rice straw-based power generation in Malaysia. It also compares rice straw-based power generation with that of coal and natural gas. GHG (Greenhouse gas) emission savings were calculated. It finds that rice straw power generation can save GHG (greenhouse gas) emissions of about 1.79 kg CO 2 -eq/kWh compared to coal-based and 1.05 kg CO 2 -eq/kWh with natural gas based power generation. While the development of rice straw-based power generation in Malaysia is still in its early stage, these paddy residues offer a large potential to generate electricity because of their availability. Rice straw power plants not only could solve the problem of removing rice straw from fields without open burning, but also could reduce GHG emissions that contribute to climate change, acidification, and eutrophication, among other environmental problems. - Highlights: • Overall rice straw preparations contribute 224.48 g CO 2 -eq/kg rice straw. • The most constraints due to GHG (greenhouse gas) emission is from transportation. • Distance collection centre to plant less than 110 km to obtains minimum emissions. • Rice straw can save GHG emissions 1.79 kg CO 2 -eq/kWh compared to coal power. • GHG saving 1.05 kg CO 2 -eq/kWh compared to natural gas based power generation

Exergetic life cycle assessment of cement production process with waste heat power generation

International Nuclear Information System (INIS)

Sui, Xiuwen; Zhang, Yun; Shao, Shuai; Zhang, Shushen

2014-01-01

Highlights: • Exergetic life cycle assessment was performed for the cement production process. • Each system’s efficiency before and after waste heat power generation was analyzed. • The waste heat power generation improved the efficiency of each production system. • It provided technical support for the implementation of energy-saving schemes. - Abstract: The cement industry is an industry that consumes a considerable quantity of resources and energy and has a very large influence on the efficient use of global resources and energy. In this study, exergetic life cycle assessment is performed for the cement production process, and the energy efficiency and exergy efficiency of each system before and after waste heat power generation is investigated. The study indicates that, before carrying out a waste heat power generation project, the objective energy efficiencies of the raw material preparation system, pulverized coal preparation system and rotary kiln system are 39.4%, 10.8% and 50.2%, respectively, and the objective exergy efficiencies are 4.5%, 1.4% and 33.7%, respectively; after carrying out a waste heat power generation project, the objective energy efficiencies are 45.8%, 15.5% and 55.1%, respectively, and the objective exergy efficiencies are 7.8%, 2.8% and 38.1%, respectively. The waste heat power generation project can recover 3.7% of the total input exergy of a rotary kiln system and improve the objective exergy efficiencies of the above three systems. The study can identify degree of resource and energy utilization and the energy-saving effect of a waste heat power generation project on each system, and provide technical support for managers in the implementation of energy-saving schemes

Integrated biomass pyrolysis with organic Rankine cycle for power generation

Science.gov (United States)

Nur, T. B.; Syahputra, A. W.

2018-02-01

The growing interest on Organic Rankine Cycle (ORC) application to produce electricity by utilizing biomass energy sources are increasingly due to its successfully used to generate power from waste heat available in industrial processes. Biomass pyrolysis is one of the thermochemical technologies for converting biomass into energy and chemical products consisting of liquid bio-oil, solid biochar, and pyrolytic gas. In the application, biomass pyrolysis can be divided into three main categories; slow, fast and flash pyrolysis mainly aiming at maximizing the products of bio-oil or biochar. The temperature of synthesis gas generated during processes can be used for Organic Rankine Cycle to generate power. The heat from synthesis gas during pyrolysis processes was transfer by thermal oil heater to evaporate ORC working fluid in the evaporator unit. In this study, the potential of the palm oil empty fruit bunch, palm oil shell, and tree bark have been used as fuel from biomass to generate electricity by integrated with ORC. The Syltherm-XLT thermal oil was used as the heat carrier from combustion burner, while R245fa was used as the working fluid for ORC system. Through Aspen Plus, this study analyses the influences on performance of main thermodynamic parameters, showing the possibilities of reaching an optimum performance for different working conditions that are characteristics of different design parameters.

Electric power generating plant having direct-coupled steam and compressed-air cycles

Science.gov (United States)

Drost, M.K.

1981-01-07

An electric power generating plant is provided with a Compressed Air Energy Storage (CAES) system which is directly coupled to the steam cycle of the generating plant. The CAES system is charged by the steam boiler during off peak hours, and drives a separate generator during peak load hours. The steam boiler load is thereby levelized throughout an operating day.

Electric power generating plant having direct coupled steam and compressed air cycles

Science.gov (United States)

Drost, Monte K.

1982-01-01

An electric power generating plant is provided with a Compressed Air Energy Storage (CAES) system which is directly coupled to the steam cycle of the generating plant. The CAES system is charged by the steam boiler during off peak hours, and drives a separate generator during peak load hours. The steam boiler load is thereby levelized throughout an operating day.

Magnetohydrodynamic power generation

International Nuclear Information System (INIS)

Sheindlin, A.E.; Jackson, W.D.; Brzozowski, W.S.; Rietjens, L.H.Th.

1979-01-01

The paper describes research and development in the field of magnetohydrodynamic power generation technology, based on discussions held in the Joint IAEA/UNESCO International Liaison Group on MHD electrical power generation. Research and development programmes on open cycle, closed cycle plasma and liquid-metal MHD are described. Open cycle MHD has now entered the engineering development stage. The paper reviews the results of cycle analyses and economic and environmental evaluations: substantial agreement has been reached on the expected overall performance and necessary component specifications. The achievement in the Soviet Union on the U-25 MHD pilot plant in obtaining full rated electrical power of 20.4 MW is described, as well as long duration testing of the integrated operation of MHD components. Work in the United States on coal-fired MHD generators has shown that, with slagging of the walls, a run time of about one hundred hours at the current density and electric field of a commercial MHD generator has been achieved. Progress obtained in closed cycle plasma and liquid metal MHD is reviewed. Electrical power densities of up to 140 MWe/m 3 and an enthalpy extraction as high as 24 per cent have been achieved in noble gas MHD generator experiments. (Auth.)

Conceptual design study of closed Brayton cycle gas turbines for fusion power generation

International Nuclear Information System (INIS)

Kuo, S.C.

1976-01-01

A conceptual design study is presented of closed Brayton cycle gas turbine power conversion systems suitable for integration with advanced-concept Tokamak fusion reactors (such as UWMAK-III) for efficient power generation without requiring cooling water supply for waste heat rejection. A baseline cycle configuration was selected and parametric performance analyses were made. Based on the results of the parametric analysis and trade-off and interface considerations, the reference design conditions for the baseline cycle were selected. Conceptual designs were made of the major helium gas turbine power system components including a 585-MWe single-shaft turbomachine, (three needed), regenerator, precooler, intercooler, and the piping system connecting them. Structural configuration and significant physical dimensions for major components are illustrated, and a brief discussion on major advantages, power control and crucial technologies for the helium gas turbine power system are presented

Rotary Stirling-Cycle Engine And Generator

Science.gov (United States)

Chandler, Joseph A.

1990-01-01

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

An optimized Fuzzy Logic Controller by Water Cycle Algorithm for power management of Stand-alone Hybrid Green Power generation

International Nuclear Information System (INIS)

Sarvi, Mohammad; Avanaki, Isa Nasiri

2015-01-01

Highlights: • A new method to improve the performance of renewable power management is proposed. • The proposed method is based on Fuzzy Logic optimized by the Water Cycle Algorithm. • The proposed method characteristics are compared with two other methods. • The comparisons confirm that the proposed method is robust and effectiveness one. - Abstract: This paper aims to improve the power management system of a Stand-alone Hybrid Green Power generation based on the Fuzzy Logic Controller optimized by the Water Cycle Algorithm. The proposed Stand-alone Hybrid Green Power consists of wind energy conversion and photovoltaic systems as primary power sources and a battery, fuel cell, and Electrolyzer as energy storage systems. Hydrogen is produced from surplus power generated by the wind energy conversion and photovoltaic systems of Stand-alone Hybrid Green Power and stored in the hydrogen storage tank for fuel cell later using when the power generated by primary sources is lower than load demand. The proposed optimized Fuzzy Logic Controller based power management system determines the power that is generated by fuel cell or use by Electrolyzer. In a hybrid system, operation and maintenance cost and reliability of the system are the important issues that should be considered in studies. In this regard, Water Cycle Algorithm is used to optimize membership functions in order to simultaneously minimize the Loss of Power Supply Probability and operation and maintenance. The results are compared with the particle swarm optimization and the un-optimized Fuzzy Logic Controller power management system to prove that the proposed method is robust and effective. Reduction in Loss of Power Supply Probability and operation and maintenance, are the most advantages of the proposed method. Moreover the level of the State of Charge of the battery in the proposed method is higher than other mentioned methods which leads to increase battery lifetime.

Magnetohydrodynamic (MHD) power generation

International Nuclear Information System (INIS)

Chandra, Avinash

1980-01-01

The concept of MHD power generation, principles of operation of the MHD generator, its design, types, MHD generator cycles, technological problems to be overcome, the current state of the art in USA and USSR are described. Progress of India's experimental 5 Mw water-gas fired open cycle MHD power generator project is reported in brief. (M.G.B.)

Integration between direct steam generation in linear solar collectors and supercritical carbon dioxide Brayton power cycles

OpenAIRE

Coco Enríquez, Luis; Muñoz Antón, Javier; Martínez-Val Peñalosa, José María

2015-01-01

Direct Steam Generation in Parabolic Troughs or Linear Fresnel solar collectors is a technology under development since beginning of nineties (1990's) for replacing thermal oils and molten salts as heat transfer fluids in concentrated solar power plants, avoiding environmental impacts. In parallel to the direct steam generation technology development, supercritical Carbon Dioxide Brayton power cycles are maturing as an alternative to traditional Rankine cycles for increasing net plant efficie...

Combined Cycle Power Generation Employing Pressure Gain Combustion

Energy Technology Data Exchange (ETDEWEB)

Holley, Adam [United Technologies Corporation, East Hartford, CT (United States). Research Center

2017-05-15

The Phase I program assessed the potential benefit of applying pressure gain combustion (PGC) technology to a natural gas combined cycle power plant. A conceptual design of the PGC integrated gas turbine was generated which was simulated in a detailed system modeling tool. The PGC integrated system was 1.93% more efficient, produced 3.09% more power, and reduced COE by 0.58%. Since the PGC system used had the same fuel flow rate as the baseline system, it also reduced CO₂ emissions by 3.09%. The PGC system did produce more NOx than standard systems, but even with the performanceand cost penalties associated with the cleanup system it is better in every measure. This technology benefits all of DOE’s stated program goals to improve plant efficiency, reduce CO₂ production, and reduce COE.

Enhancing power cycle efficiency for a supercritical Brayton cycle power system using tunable supercritical gas mixtures

Science.gov (United States)

Wright, Steven A.; Pickard, Paul S.; Vernon, Milton E.; Radel, Ross F.

2017-08-29

Various technologies pertaining to tuning composition of a fluid mixture in a supercritical Brayton cycle power generation system are described herein. Compounds, such as Alkanes, are selectively added or removed from an operating fluid of the supercritical Brayton cycle power generation system to cause the critical temperature of the fluid to move up or down, depending upon environmental conditions. As efficiency of the supercritical Brayton cycle power generation system is substantially optimized when heat is rejected near the critical temperature of the fluid, dynamically modifying the critical temperature of the fluid based upon sensed environmental conditions improves efficiency of such a system.

Challenges and solutions for adoption of advanced cycles for power generation in today's business climate

International Nuclear Information System (INIS)

Brockway, D.

2002-01-01

Total world electricity production is forecast to nearly double over the next 25 years. Dependence on fossil fuels for electricity production will continue to dominate through this period and well into the future. Currently, coal is the fuel for about 30% of total installed power generation capacity and the coal share of the electricity market is expected to remain essentially steady over the 25 year period. Nevertheless, the amount of coal consumed for power generation will increase substantially. It is expected that world coal-fired power production will grow at an average rate of 3% per annum. The forecast demand growth for power generation will require an investment of the order of US$3 trillion with about US$1 trillion in coal-fired power generation. In Australia, coal is the principal fuel for power generation, providing more than 80% of electricity production. Two thirds of electricity generation from coal in Australia relies on high-rank coals (bituminous coals) and one-third on low-rank coals (brown coals and lignite). Coal will remain the principal fuel for electricity generation, in Australia and worldwide, for many decades to come. The relatively low cost of coal in Australia, particularly brown coal in Victoria, provides the nation with an important international competitive advantage - low cost energy for industry, business and domestic consumers. However, projections by the National Electricity Market Management Company Limited (NEMMCO 2001) clearly show a looming critical shortfall in baseload supply within a decade, possibly within five or six years, in the Victorian and South Australian markets. This baseload requirement can only be partly addressed through interstate connections and cannot be met with existing plans for open cycle gas turbine peaking plant. For Australia to continue to benefit from its international competitive advantage from relatively low energy costs, there is a need to install new brown coal fired baseload power generation

Life cycle analysis on carbon emissions from power generation – The nuclear energy example

International Nuclear Information System (INIS)

Nian, Victor; Chou, S.K.; Su, Bin; Bauly, John

2014-01-01

Highlights: • This paper discusses about a methodology on the life cycle analysis of power generation using nuclear as an example. • The methodology encompasses generic system, input–output, and boundaries definitions. • The boundaries facilitate the use of Kaya Identity and decomposition technique to identify carbon emission streams. - Abstract: A common value of carbon emission factor, t-CO 2 /GWh, in nuclear power generation reported in the literature varies by more than a factor of 100. Such a variation suggests a margin of uncertainty and reliability. In this study, we employ a bottom-up approach to better define the system, its input and output, and boundaries. This approach offers improved granularity at the process level and consistency in the results. Based on this approach, we have developed a methodology to enable comparison of carbon emissions from nuclear power generation. The proposed methodology employs the principle of energy balance on a defined power generation system. The resulting system boundary facilitates the use of the “Kaya Identity” and the decomposition technique to identify the carbon emission streams. Using nuclear power as a case study, we obtained a carbon emission factor of 22.80 t-CO 2 /GWh, which falls to within 2.5% of the median of globally reported LCA results. We demonstrate that the resulting methodology could be used as a generic tool for life cycle analysis of carbon emissions from other power generation technologies and systems

Power generation from a 7700C heat source by means of a main steam cycle, a topping closed gas cycle and a ammonia bottoming cycle

International Nuclear Information System (INIS)

Tilliette, Z.P.

1981-03-01

For power generation, steam cycles make an efficient use of medium temperature heat sources. They can be adapted to dry cooling, higher power ratings and output increase in winter by addition of an ammonia bottoming cycle. Active development is carried out in this field by 'Electricite de France'. As far as heat sources at higher temperatures are concerned, particularly related to coal-fired or nuclear power plants, a more efficient way of converting energy is at first to expand a hot working fluid through a gas turbine. It is shown in this paper that a satisfactory result, for heat sources of about 770 0 C, is obtained with a topping closed gas cycle of moderate power rating, rejecting its waste heat into the main steam cycle. Attention has to be paid to this gas cycle waste heat recovery and to the coupling of the gas and steam cycles. This concept drastically reduces the importance of new technology components. The use and the significance of an ammonia bottoming cycle in this case are investigated

Fast power cycle for fusion reactors

International Nuclear Information System (INIS)

Powell, J.; Fillo, J.; Makowitz, H.

1978-01-01

The unique, deep penetration capability of 14 MeV neutrons produced in DT fusion reactions allows the generation of very high temperature working fluid temperatures in a thermal power cycle. In the FAST (Fusion Augmented Steam Turbine) power cycle steam is directly superheated by the high temperature ceramic refractory interior of the blanket, after being generated by heat extracted from the relatively cool blanket structure. The steam is then passed to a high temperature gas turbine for power generation. Cycle studies have been carried out for a range of turbine inlet temperatures [1600 0 F to 3000 0 F (870 to 1650 0 C)], number of reheats, turbine mechanical efficiency, recuperator effectiveness, and system pressure losses. Gross cycle efficiency is projected to be in the range of 55 to 60%, (fusion energy to electric power), depending on parameters selected. Turbine inlet temperatures above 2000 0 F, while they do increase efficiency somewhat, are not necessarily for high cycle efficiency

Utilization of waste heat from GT-MHR for power generation in organic Rankine cycles

International Nuclear Information System (INIS)

Yari, Mortaza; Mahmoudi, S.M.S.

2010-01-01

The gas turbine-modular helium reactor (GT-MHR) is currently being developed by an international consortium. In this power plant, circulating helium that has to be compressed in a single or two successive stages cools the reactor core. For thermodynamic reasons, these compression stages require pre-cooling of the helium to about 26 deg. C through the use of intercooler and pre-cooler in which water is used to cool the helium. Considerable thermal energy (∼300 MWth) is thus dissipated in these components. This thermal energy is then rejected to a heat sink. For different designs, the temperature ranges of the helium in the intercooler and pre-cooler could be about 100 and 150 deg. C, respectively. These are ideal energy sources to be used in an organic Rankine cycles for power generation. This study examines the performance of a gas-cooled nuclear power plant with closed Brayton cycle (CBC) combined with two organic Rankine cycles (ORC). More attention was paid to the irreversibilities generated in the combined cycle. Individual models are developed for each component through applications of the first and second laws of thermodynamics. The effects of the turbine inlet temperature, compressor pressure ratio, evaporator temperature and temperature difference in the evaporator on the first- and second-law efficiencies and on the exergy destruction rate of the combined cycle were studied. Finally the combined cycle was optimized thermodynamically using the EES (Engineering Equation Solver) software. Based on identical operating conditions, a comparison between the GT-MHR/ORC and a simple GT-MHR cycle is also made. It was found that both the first- and second-law efficiencies of GT-MHR/ORC cycle are about 3%-points higher than that of the simple GT-MHR cycle. Also, the exergy destruction rate for GT-MHR/ORC cycle is about 5% lower than that of the GT-MHR cycle.

Oxygen blast furnace and combined cycle (OBF-CC) - an efficient iron-making and power generation process

International Nuclear Information System (INIS)

Jianwei, Y.; Guolong, S.; Cunjiang, K.; Tianjun, Y.

2003-01-01

A new iron and power generating process, oxygen blast furnace and combined cycle (OBF-CC), is presented. In order to support the opinion, the features of the oxygen blast furnace and integrated coal gasification and combined cycle (IGCC) are summarized. The relation between the blasting parameters and the output gas quantity, as well as caloric value is calculated based on mass and energy balance. Analysis and calculation indicate that the OBF-CC will be an efficient iron-making and power generation process with higher energy efficiency and less pollution

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

Science.gov (United States)

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.

Thermal cycle efficiency of the indirect combined HTGR-GT power generation system

Energy Technology Data Exchange (ETDEWEB)

Muto, Yasushi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1996-02-01

High thermal efficiency of 50% could be expected in a power generation system coupling a high temperature gas-cooled reactor(HTGR) with a closed cycle gas turbine(GT). There are three candidate systems such as a direct cycle(DC), an indirect cycle(ICD) and an indirect combined cycle(IDCC). The IDCC could solve many problems in both the DC and the IDC and consists of a primary circuit and a secondary circuit where a topping cycle is a Brayton cycle and a bottoming cycle is a steam cycle. In this report, the thermal cycle efficiency of the IDCC is examined regarding configurations of components and steam pressure. It has been shown that there are two types of configurations, that is, a perfect cascade type and a semi-cascade one and the latter can be further classified into Case A, Case B and Case C. The conditions achieving the maximum thermal cycle efficiency were revealed for these cases. In addition, the optimum system configurations were proposed considering the thermal cycle efficiency, safety and plant arrangement. (author).

Microfabricated rankine cycle steam turbine for power generation and methods of making the same

Science.gov (United States)

Frechette, Luc (Inventor); Muller, Norbert (Inventor); Lee, Changgu (Inventor)

2009-01-01

In accordance with the present invention, an integrated micro steam turbine power plant on-a-chip has been provided. The integrated micro steam turbine power plant on-a-chip of the present invention comprises a miniature electric power generation system fabricated using silicon microfabrication technology and lithographic patterning. The present invention converts heat to electricity by implementing a thermodynamic power cycle on a chip. The steam turbine power plant on-a-chip generally comprises a turbine, a pump, an electric generator, an evaporator, and a condenser. The turbine is formed by a rotatable, disk-shaped rotor having a plurality of rotor blades disposed thereon and a plurality of stator blades. The plurality of stator blades are interdigitated with the plurality of rotor blades to form the turbine. The generator is driven by the turbine and converts mechanical energy into electrical energy.

Gas-steam combined cycles for power generation: Current state-of-the-art and future prospects

International Nuclear Information System (INIS)

Macchi, E.; Chiesa, P.; Consonni, S.; Lozza, G.

1992-01-01

The first part of this paper points out the many factors which, after years of stagnation in the electric power industry, are giving rise to a true revolution in power generation engineering: the passing from closed cycles, using steam as the working fluid and energy sources external to the power cycle, to the use of open cycles, in which the primary energy source, in the form of a fuel, is directly immersed in the working fluid of the engine. Attention is given to the advantages in terms of energy and cost savings, greater flexibility in energy policy options and pollution abatement which are now being afforded through the use of gas turbines with combined gas-steam cycles. The second part of the paper deals with an assessment of the current state-of-the-art of the technology relative to these innovative power systems. The assessment is followed by a review of foreseen developments in combined cycle system design, choice of construction materials, type of cooling systems, operating temperatures and performance capabilities

Optimisation of a Kalina cycle for a central receiver solar thermal power plant with direct steam generation

DEFF Research Database (Denmark)

Modi, Anish; Haglind, Fredrik

2014-01-01

Central receiver solar thermal power plants are regarded as one of the promising ways to generate electricity in near future. They offer the possibility of using high temperatures and pressures to achieve high efficiencies with standard power cycles. A direct steam generation approach can be used...

Electricity from MHD, 1968. Vol. IV. Open-Cycle MHD. Proceedings of a Symposium on Magnetohydrodynamic Electrical Power Generation

International Nuclear Information System (INIS)

1968-01-01

Proceedings of a Symposium on Magnetohydrodynamic Electrical Power Generation held by the IAEA at Warsaw, 24-30 July 1968. The meeting was attended by some 300 participants from 21 countries and three international organizations. In contrast to the Symposium held two years ago, much more emphasis was placed on the economic aspects of using MHD generators in large-scale power generation. Among closed- cycle systems, the prospects of linking an ultra-high-temperature reactor with an MHD generator were explored, and the advantages gained by having a liquid-metal generator as a 'topper' in a conventional steam generating plant were presented. Comments were made about the disproportionate effect of end and boundary conditions in experimental MHD generators on the main plasma parameters, and estimates were made of the interrelationship to be expected in real generators. The estimates will have to await confirmation until results are obtained on large-scale prototype MHD systems. Progress in materials research, in design and construction of auxiliary equipment such as heat exchangers, supercooled magnets (which are- now commercially available), etc., is accompanied by sophisticated ideas of plant design. The Proceedings are complemented by three Round Table Discussions in which chosen experts from various countries discuss the outlook for closed-cycle gas, closed-cycle liquid-metal and open-cycle MHD, and give their views as to the most fruitful course to follow to achieve economic full-scale power generation. Contents: (Vol. I) 1. Closed-Cycle MHD with Gaseous Working Fluids: (a) Diagnostics (3 papers); (b) Steady-state non-equilibrium ionization (8 papers); (c) Transient non-equilibrium ionization (7 papers); (d) Pre-ionization and gas discharge (4 papers); (e) Fields and flow in MHD channels (10 papers); (0 Instabilities (8 papers); (g) Generator design and performance studies (6 papers); (Vol. II) (h) Shock waves (6 papers); (i) Power generation experiments (13 papers

Investigation of thermodynamic performances for two solar-biomass hybrid combined cycle power generation systems

International Nuclear Information System (INIS)

Liu, Qibin; Bai, Zhang; Wang, Xiaohe; Lei, Jing; Jin, Hongguang

2016-01-01

Highlights: • Two solar-biomass hybrid combined cycle power generation systems are proposed. • The characters of the two proposed systems are compared. • The on-design and off-design properties of the system are numerically investigated. • The favorable performances of thermochemical hybrid routine are validated. - Abstract: Two solar-biomass hybrid combined cycle power generation systems are proposed in this work. The first system employs the thermochemical hybrid routine, in which the biomass gasification is driven by the concentrated solar energy, and the gasified syngas as a solar fuel is utilized in a combined cycle for generating power. The second system adopts the thermal integration concept, and the solar energy is directly used to heat the compressed air in the topping Brayton cycle. The thermodynamic performances of the developed systems are investigated under the on-design and off-design conditions. The advantages of the hybrid utilization technical mode are demonstrated. The solar energy can be converted and stored into the chemical fuel by the solar-biomass gasification, with the net solar-to-fuel efficiency of 61.23% and the net solar share of 19.01% under the specific gasification temperature of 1150 K. Meanwhile, the proposed system with the solar thermochemical routine shows more favorable behaviors, the annual system overall energy efficiency and the solar-to-electric efficiency reach to 29.36% and 18.49%, while the with thermal integration concept of 28.03% and 15.13%, respectively. The comparison work introduces a promising approach for the efficient utilization of the abundant solar and biomass resources in the western China, and realizes the mitigation of CO_2 emission.

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)

Life cycle analysis of geothermal power generation with supercritical carbon dioxide

International Nuclear Information System (INIS)

Frank, Edward D; Sullivan, John L; Wang, Michael Q

2012-01-01

Life cycle analysis methods were employed to model the greenhouse gas emissions and fossil energy consumption associated with geothermal power production when supercritical carbon dioxide (scCO 2 ) is used instead of saline geofluids to recover heat from below ground. Since a significant amount of scCO 2 is sequestered below ground in the process, a constant supply is required. We therefore combined the scCO 2 geothermal power plant with an upstream coal power plant that captured a portion of its CO 2 emissions, compressed it to scCO 2 , and transported the scCO 2 by pipeline to the geothermal power plant. Emissions and energy consumption from all operations spanning coal mining and plant construction through power production were considered, including increases in coal use to meet steam demand for the carbon capture. The results indicated that the electricity produced by the geothermal plant more than balanced the increase in energy use resulting from carbon capture at the coal power plant. The effective heat rate (BTU coal per total kW h of electricity generated, coal plus geothermal) was comparable to that of traditional coal, but the ratio of life cycle emissions from the combined system to that of traditional coal was 15% when 90% carbon capture efficiency was assumed and when leakage from the surface was neglected. Contributions from surface leakage were estimated with a simple model for several hypothetical surface leakage rates. (letter)

Preliminary design of S-CO{sub 2} Brayton cycle for APR-1400 with power generation and desalination process

Energy Technology Data Exchange (ETDEWEB)

Bae, Seong Jun; Lee, Won Woong; Jeong, Yong Hoon; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Yoon, Ho Joon [KUSTAR, Abu Dhabi (United Arab Emirates)

2015-10-15

This study was conducted to explore the capabilities of the S-CO{sub 2} Brayton cycle for a cogeneration system for APR-1400 application. Three concepts of the S-CO{sub 2} simple recuperated co-generation cycle were designed. A supercritical CO{sub 2} (S-CO{sub 2}) Brayton cycle is recently receiving significant attention as a promising power conversion system in wide range of energy applications due to its high efficiency and compact footprint. The main reason why the S-CO{sub 2} Brayton cycle has these advantages is that the compressor operates near the critical point of CO{sub 2} (30.98 .deg. C, 7.38MPa) to reduce the compression work significantly compared to the other Brayton cycles. In this study, the concept of replacing the entire steam cycle of APR-1400 with the S-CO{sub 2} Brayton cycle is evaluated. The power generation purpose S-CO{sub 2} Brayton cycles are redesigned to generate power and provide heat to the desalination system at the same time. The performance of these newly suggested cycles are evaluated in this paper. The target was to deliver 147MW heat to the desalination process. The thermal efficiencies of the three concepts are not significantly different, but the 3{sup rd} concept is relatively simpler than other cycles because only an additional heat exchanger is required. Although the 2{sup nd} concept is relatively complicated in comparison to other concepts, the temperatures at the inlet and outlet of the DHX are higher than that of the others. As shown in the results, the S-CO{sub 2} Brayton cycles are not easy to outperform the steam cycle with very simple layout and general design points under APR-1400 operating condition. However, this study shows that the S-CO{sub 2} Brayton cycles can be designed as a co-generation cycle while producing the target desalination heat with a simple configuration. In addition, it was also found that the S-CO{sub 2} Brayton cycle can achieve higher cycle thermal efficiency than the steam power cycle under

A performance analysis for MHD power cycles operating at maximum power density

International Nuclear Information System (INIS)

Sahin, Bahri; Kodal, Ali; Yavuz, Hasbi

1996-01-01

An analysis of the thermal efficiency of a magnetohydrodynamic (MHD) power cycle at maximum power density for a constant velocity type MHD generator has been carried out. The irreversibilities at the compressor and the MHD generator are taken into account. The results obtained from power density analysis were compared with those of maximum power analysis. It is shown that by using the power density criteria the MHD cycle efficiency can be increased effectively. (author)

Nuclear power generation and fuel cycle report 1997

International Nuclear Information System (INIS)

1997-09-01

Nuclear power is an important source of electric energy and the amount of nuclear-generated electricity continued to grow as the performance of nuclear power plants improved. In 1996, nuclear power plants supplied 23 percent of the electricity production for countries with nuclear units, and 17 percent of the total electricity generated worldwide. However, the likelihood of nuclear power assuming a much larger role or even retaining its current share of electricity generation production is uncertain. The industry faces a complex set of issues including economic competitiveness, social acceptance, and the handling of nuclear waste, all of which contribute to the uncertain future of nuclear power. Nevertheless, for some countries the installed nuclear generating capacity is projected to continue to grow. Insufficient indigenous energy resources and concerns over energy independence make nuclear electric generation a viable option, especially for the countries of the Far East

Nuclear power generation and fuel cycle report 1997

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-09-01

Nuclear power is an important source of electric energy and the amount of nuclear-generated electricity continued to grow as the performance of nuclear power plants improved. In 1996, nuclear power plants supplied 23 percent of the electricity production for countries with nuclear units, and 17 percent of the total electricity generated worldwide. However, the likelihood of nuclear power assuming a much larger role or even retaining its current share of electricity generation production is uncertain. The industry faces a complex set of issues including economic competitiveness, social acceptance, and the handling of nuclear waste, all of which contribute to the uncertain future of nuclear power. Nevertheless, for some countries the installed nuclear generating capacity is projected to continue to grow. Insufficient indigenous energy resources and concerns over energy independence make nuclear electric generation a viable option, especially for the countries of the Far East.

Solar thermal aided power generation

International Nuclear Information System (INIS)

Hu, Eric; Yang, YongPing; Nishimura, Akira; Yilmaz, Ferdi; Kouzani, Abbas

2010-01-01

Fossil fuel based power generation is and will still be the back bone of our world economy, albeit such form of power generation significantly contributes to global CO 2 emissions. Solar energy is a clean, environmental friendly energy source for power generation, however solar photovoltaic electricity generation is not practical for large commercial scales due to its cost and high-tech nature. Solar thermal is another way to use solar energy to generate power. Many attempts to establish solar (solo) thermal power stations have been practiced all over the world. Although there are some advantages in solo solar thermal power systems, the efficiencies and costs of these systems are not so attractive. Alternately by modifying, if possible, the existing coal-fired power stations to generate green sustainable power, a much more efficient means of power generation can be reached. This paper presents the concept of solar aided power generation in conventional coal-fired power stations, i.e., integrating solar (thermal) energy into conventional fossil fuelled power generation cycles (termed as solar aided thermal power). The solar aided power generation (SAPG) concept has technically been derived to use the strong points of the two technologies (traditional regenerative Rankine cycle with relatively higher efficiency and solar heating at relatively low temperature range). The SAPG does not only contribute to increase the efficiencies of the conventional power station and reduce its emission of the greenhouse gases, but also provides a better way to use solar heat to generate the power. This paper presents the advantages of the SAPG at conceptual level.

Performance characterization of a power generation unit–organic Rankine cycle system based on the efficiencies of the system components

International Nuclear Information System (INIS)

Knizley, Alta; Mago, Pedro J.; Tobermann, James; Warren, Harrison R.

2015-01-01

Highlights: • Use of waste heat from a power generation unit to generate electricity is explored. • An organic Rankine cycle is used to recover the waste heat. • The system may lower cost, primary energy consumption, and carbon dioxide emission. • A parameter was established to show when the proposed system would provide savings. • The proposed system was evaluated in different locations in the US. - Abstract: This paper analyzes the potential of using the waste heat from a power generation unit to generate additional electricity using an organic Rankine cycle to reduce operational cost, primary energy consumption, and carbon dioxide emissions in different locations in the U.S. The power generation unit–organic Rankine cycle system is compared with a conventional system in terms of operational cost, primary energy consumption, and carbon dioxide emissions reduction. A parameter (R_m_i_n), which is based on system efficiencies, is established to determine when the proposed power generation unit–organic Rankine cycle system would potentially provide savings versus the conventional system in which electricity is purchased from the utility grid. The effect on the R_m_i_n parameter with variation of each system efficiency is also analyzed in this paper. Results indicated that savings in one parameter, such as primary energy consumption, did not imply savings in the other two parameters. Savings in the three parameters (operational cost, primary energy consumption, and carbon dioxide emissions) varied widely based on location due to prices of natural gas and electricity, source-to-site conversion factors, and carbon dioxide emissions conversion factors for electricity and natural gas. Variations in each system efficiency affected R_m_i_n, but varying the power generation unit efficiency had the most dramatic effect in the overall savings potential from the proposed system.

Evaluation of material integrity on electricity power steam generator cycles (turbine casing) component

International Nuclear Information System (INIS)

Histori; Benedicta; Farokhi; S A, Soedardjo; Triyadi, Ari; Natsir, M

1999-01-01

The evaluation of material integrity on power steam generator cycles component was done. The test was carried out on casing turbine which is made from Inconel 617. The tested material was taken from t anjung Priok plant . The evaluation was done by metallography analysis using microscope with magnification of 400. From the result, it is shown that the material grains are equiaxed

Low temperature heat source for power generation: Exhaustive analysis of a carbon dioxide transcritical power cycle

International Nuclear Information System (INIS)

Velez, Fredy; Segovia, Jose; Chejne, Farid; Antolin, Gregorio; Quijano, Ana; Carmen Martin, M.

2011-01-01

The main results of a theoretical work on the use of a low temperature heat source for power generation through a carbon dioxide transcritical power cycle are reported in this paper. The procedure for analyzing the behaviour of the proposed cycle consisted in modifying the input pressure to the turbine from 66 bar, maintained constant each evaluated temperature (60 o C, 90 o C, 120 o C and 150 o C) until the net work was approximately zero. As a result, the maximum exergy efficiency was 50%, while the energy efficiencies obtained were 9.8%, 7.3%, 4.9% and 2.4% and the net specific work was 18.2 kJ/kg, 12.8 kJ/kg, 7.8 kJ/kg and 3.5 kJ/kg, respectively. Furthermore, the effect of the addition of an internal heat exchanger, which obviously supposed an increase in the efficiency, was analyzed. The analysis of the proposed system shows the viability of implementing this type of process as an energy alternative and/or strengthener of non-conventional energy sources in non-provided zones, or for increasing the energy efficiency in the industry. -- Highlights: → Energy and exergy analysis of a carbon dioxide transcritical power cycle is reported. → The effect of the inlet temperature to the turbine is evaluated. → Conditions of maximum efficiency and maximum net work are compared. → The inclusion of an IHX is also analysed.

Next Generation Geothermal Power Plants

Energy Technology Data Exchange (ETDEWEB)

Brugman, John; Hattar, Mai; Nichols, Kenneth; Esaki, Yuri

1995-09-01

A number of current and prospective power plant concepts were investigated to evaluate their potential to serve as the basis of the next generation geothermal power plant (NGGPP). The NGGPP has been envisaged as a power plant that would be more cost competitive (than current geothermal power plants) with fossil fuel power plants, would efficiently use resources and mitigate the risk of reservoir under-performance, and minimize or eliminate emission of pollutants and consumption of surface and ground water. Power plant concepts were analyzed using resource characteristics at ten different geothermal sites located in the western United States. Concepts were developed into viable power plant processes, capital costs were estimated and levelized busbar costs determined. Thus, the study results should be considered as useful indicators of the commercial viability of the various power plants concepts that were investigated. Broadly, the different power plant concepts that were analyzed in this study fall into the following categories: commercial binary and flash plants, advanced binary plants, advanced flash plants, flash/binary hybrid plants, and fossil/geothed hybrid plants. Commercial binary plants were evaluated using commercial isobutane as a working fluid; both air-cooling and water-cooling were considered. Advanced binary concepts included cycles using synchronous turbine-generators, cycles with metastable expansion, and cycles utilizing mixtures as working fluids. Dual flash steam plants were used as the model for the commercial flash cycle. The following advanced flash concepts were examined: dual flash with rotary separator turbine, dual flash with steam reheater, dual flash with hot water turbine, and subatmospheric flash. Both dual flash and binary cycles were combined with other cycles to develop a number of hybrid cycles: dual flash binary bottoming cycle, dual flash backpressure turbine binary cycle, dual flash gas turbine cycle, and binary gas turbine

Study on closed cycle MHD generation systems; Closed cycle MHD hatsuden system no kento

Energy Technology Data Exchange (ETDEWEB)

NONE

1988-03-01

The closed cycle noble gas MHD generation systems are surveyed and studied. The concept of closed cycle noble gas MHD generation is confirmed to extract high enthalpy, and now going into the engineering demonstration stage from the basic research stage. These systems have various characteristics. The highest working temperature is around 1,700 degrees C, which is close to that associated with the existing techniques. Use of helium or argon gas as the working fluid makes the system relatively free of various problems, e.g., corrosion. It can attain a much higher efficiency than the combined cycle involving gas turbine. It suffers less heat loss in the passages, is suitable for small- to medium-capacity power generation systems, and copes with varying load. The compact power generation passages decrease required size of the superconducting magnet. The technical problems to be solved include optimization of power generation conditions, demonstration of durability of the power generation passages, injection/recovery of the seed material, treatment of the working gas to remove molecular impurities, and development of heat exchangers serviceable at high temperature produced by direct combustion of coal. The conceptual designs of the triple combined system are completed. (NEDO)

Optimum gas turbine cycle for combined cycle power plant

International Nuclear Information System (INIS)

Polyzakis, A.L.; Koroneos, C.; Xydis, G.

2008-01-01

The gas turbine based power plant is characterized by its relatively low capital cost compared with the steam power plant. It has environmental advantages and short construction lead time. However, conventional industrial engines have lower efficiencies, especially at part load. One of the technologies adopted nowadays for efficiency improvement is the 'combined cycle'. The combined cycle technology is now well established and offers superior efficiency to any of the competing gas turbine based systems that are likely to be available in the medium term for large scale power generation applications. This paper has as objective the optimization of a combined cycle power plant describing and comparing four different gas turbine cycles: simple cycle, intercooled cycle, reheated cycle and intercooled and reheated cycle. The proposed combined cycle plant would produce 300 MW of power (200 MW from the gas turbine and 100 MW from the steam turbine). The results showed that the reheated gas turbine is the most desirable overall, mainly because of its high turbine exhaust gas temperature and resulting high thermal efficiency of the bottoming steam cycle. The optimal gas turbine (GT) cycle will lead to a more efficient combined cycle power plant (CCPP), and this will result in great savings. The initial approach adopted is to investigate independently the four theoretically possible configurations of the gas plant. On the basis of combining these with a single pressure Rankine cycle, the optimum gas scheme is found. Once the gas turbine is selected, the next step is to investigate the impact of the steam cycle design and parameters on the overall performance of the plant, in order to choose the combined cycle offering the best fit with the objectives of the work as depicted above. Each alterative cycle was studied, aiming to find the best option from the standpoint of overall efficiency, installation and operational costs, maintainability and reliability for a combined power

Energy and exergy analysis of a closed Brayton cycle-based combined cycle for solar power tower plants

International Nuclear Information System (INIS)

Zare, V.; Hasanzadeh, M.

2016-01-01

Highlights: • A novel combined cycle is proposed for solar power tower plants. • The effects of solar subsystem and power cycle parameters are examined. • The proposed combined cycle yields exergy efficiencies of higher than 70%. • For the overall power plant exergy efficiencies of higher than 30% is achievable. - Abstract: Concentrating Solar Power (CSP) technology offers an interesting potential for future power generation and research on CSP systems of all types, particularly those with central receiver system (CRS) has been attracting a lot of attention recently. Today, these power plants cannot compete with the conventional power generation systems in terms of Levelized Cost of Electricity (LCOE) and if a competitive LCOE is to be reached, employing an efficient thermodynamic power cycle is deemed essential. In the present work, a novel combined cycle is proposed for power generation from solar power towers. The proposed system consists of a closed Brayton cycle, which uses helium as the working fluid, and two organic Rankine cycles which are employed to recover the waste heat of the Brayton cycle. The system is thermodynamically assessed from both the first and second law viewpoints. A parametric study is conducted to examine the effects of key operating parameters (including solar subsystem and power cycle parameters) on the overall power plant performance. The results indicate that exergy efficiencies of higher than 30% are achieved for the overall power plant. Also, according to the results, the power cycle proposed in this work has a better performance than the other investigated Rankine and supercritical CO_2 systems operating under similar conditions, for these types of solar power plants.

Performance analysis of a Kalina cycle for a central receiver solar thermal power plant with direct steam generation

International Nuclear Information System (INIS)

Modi, Anish; Haglind, Fredrik

2014-01-01

Solar thermal power plants have attracted increasing interest in the past few years – with respect to both the design of the various plant components, and extending the operation hours by employing different types of storage systems. One approach to improve the overall plant efficiency is to use direct steam generation with water/steam as both the heat transfer fluid in the solar receivers and the cycle working fluid. This enables operating the plant with higher turbine inlet temperatures. Available literature suggests that it is feasible to use ammonia-water mixtures at high temperatures without corroding the equipment by using suitable additives with the mixture. The purpose of the study reported here was to investigate if there is any benefit of using a Kalina cycle for a direct steam generation, central receiver solar thermal power plant with high live steam temperature (450 °C) and pressure (over 100 bar). Thermodynamic performance of the Kalina cycle in terms of the plant exergy efficiency was evaluated and compared with a simple Rankine cycle. The rates of exergy destruction for the different components in the two cycles were also calculated and compared. The results suggest that the simple Rankine cycle exhibits better performance than the Kalina cycle when the heat input is only from the solar receiver. However, when using a two-tank molten-salt storage system as the primary source of heat input, the Kalina cycle showed an advantage over the simple Rankine cycle because of about 33 % reduction in the storage requirement. The solar receiver showed the highest rate of exergy destruction for both the cycles. The rates of exergy destruction in other components of the cycles were found to be highly dependent on the amount of recuperation, and the ammonia mass fraction and pressure at the turbine inlet. - Highlights: •Kalina cycle for a central receiver solar thermal power plant with direct steam generation. •Rankine cycle shows better plant exergy

Radioactive Waste Generation in Pyro-SFR Nuclear Fuel Cycle

International Nuclear Information System (INIS)

Gao, Fanxing; Park, Byung Heung; Ko, Won Il

2011-01-01

Which nuclear fuel cycle option to deploy is of great importance in the sustainability of nuclear power. SFR fuel cycle employing pyroprocessing (named as Pyro- SFR Cycle) is one promising fuel cycle option in the near future. Radioactive waste generation is a key criterion in nuclear fuel cycle system analysis, which considerably affects the future development of nuclear power. High population with small territory is one special characteristic of ROK, which makes the waste management pretty important. In this study, particularly the amount of waste generation with regard to the promising advanced fuel cycle option was evaluated, because the difficulty of deploying an underground repository for HLW disposal requires a longer time especially in ROK

Advanced energy utilization MHD power generation

International Nuclear Information System (INIS)

2008-01-01

The 'Technical Committee on Advanced Energy Utilization MHD Power Generation' was started to establish advanced energy utilization technologies in Japan, and has been working for three years from June 2004 to May 2007. This committee investigated closed cycle MHD, open cycle MHD, and liquid metal MHD power generation as high-efficiency power generation systems on the earth. Then, aero-space application and deep space exploration technologies were investigated as applications of MHD technology. The spin-off from research and development on MHD power generation such as acceleration and deceleration of supersonic flows was expected to solve unstart phenomena in scramjet engine and also to solve abnormal heating of aircrafts by shock wave. In addition, this committee investigated researches on fuel cells, on secondary batteries, on connection of wind power system to power grid, and on direct energy conversion system from nuclear fusion reactor for future. The present technical report described results of investigations by the committee. (author)

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

Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic...... 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...

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

International Nuclear Information System (INIS)

Tarlecki, Jason; Lior, Noam; Zhang Na

2007-01-01

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 (N 2 and H 2 ) 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

Energy and exergy analysis of the Kalina cycle for use in concentrated solar power plants with direct steam generation

DEFF Research Database (Denmark)

Knudsen, Thomas; Clausen, Lasse Røngaard; Haglind, Fredrik

2014-01-01

In concentrated solar power plants using direct steam generation, the usage of a thermal storage unit based only on sensible heat may lead to large exergetic losses during charging and discharging, due to a poor matching of the temperature profiles. By the use of the Kalina cycle, in which...... evaporation and condensation takes place over a temperature range, the efficiency of the heat exchange processes can be improved, possibly resulting also in improved overall performance of the system. This paper is aimed at evaluating the prospect of using the Kalina cycle for concentrated solar power plants...... with direct steam generation. The following two scenarios were addressed using energy and exergy analysis: generating power using heat from only the receiver and using only stored heat. For each of these scenarios comparisons were made for mixture concentrations ranging from 0.1 mole fraction of ammonia to 0...

Solar thermal organic rankine cycle for micro-generation

Science.gov (United States)

Alkahli, N. A.; Abdullah, H.; Darus, A. N.; Jalaludin, A. F.

2012-06-01

The conceptual design of an Organic Rankine Cycle (ORC) driven by solar thermal energy is developed for the decentralized production of electricity of up to 50 kW. Conventional Rankine Cycle uses water as the working fluid whereas ORC uses organic compound as the working fluid and it is particularly suitable for low temperature applications. The ORC and the solar collector will be sized according to the solar flux distribution in the Republic of Yemen for the required power output of 50 kW. This will be a micro power generation system that consists of two cycles, the solar thermal cycle that harness solar energy and the power cycle, which is the ORC that generates electricity. As for the solar thermal cycle, heat transfer fluid (HTF) circulates the cycle while absorbing thermal energy from the sun through a parabolic trough collector and then storing it in a thermal storage to increase system efficiency and maintains system operation during low radiation. The heat is then transferred to the organic fluid in the ORC via a heat exchanger. The organic fluids to be used and analyzed in the ORC are hydrocarbons R600a and R290.

Applicability of the minimum entropy generation method for optimizing thermodynamic cycles

Institute of Scientific and Technical Information of China (English)

Cheng Xue-Tao; Liang Xin-Gang

2013-01-01

Entropy generation is often used as a figure of merit in thermodynamic cycle optimizations.In this paper,it is shown that the applicability of the minimum entropy generation method to optimizing output power is conditional.The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power when the total heat into the system of interest is not prescribed.For the cycles whose working medium is heated or cooled by streams with prescribed inlet temperatures and prescribed heat capacity flow rates,it is theoretically proved that both the minimum entropy generation rate and the minimum entropy generation number correspond to the maximum output power when the virtual entropy generation induced by dumping the used streams into the environment is considered.However,the minimum principle of entropy generation is not tenable in the case that the virtual entropy generation is not included,because the total heat into the system of interest is not fixed.An irreversible Carnot cycle and an irreversible Brayton cycle are analysed.The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power if the heat into the system of interest is not prescribed.

Applicability of the minimum entropy generation method for optimizing thermodynamic cycles

International Nuclear Information System (INIS)

Cheng Xue-Tao; Liang Xin-Gang

2013-01-01

Entropy generation is often used as a figure of merit in thermodynamic cycle optimizations. In this paper, it is shown that the applicability of the minimum entropy generation method to optimizing output power is conditional. The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power when the total heat into the system of interest is not prescribed. For the cycles whose working medium is heated or cooled by streams with prescribed inlet temperatures and prescribed heat capacity flow rates, it is theoretically proved that both the minimum entropy generation rate and the minimum entropy generation number correspond to the maximum output power when the virtual entropy generation induced by dumping the used streams into the environment is considered. However, the minimum principle of entropy generation is not tenable in the case that the virtual entropy generation is not included, because the total heat into the system of interest is not fixed. An irreversible Carnot cycle and an irreversible Brayton cycle are analysed. The minimum entropy generation rate and the minimum entropy generation number do not correspond to the maximum output power if the heat into the system of interest is not prescribed. (general)

A numerical analysis of a composition-adjustable Kalina cycle power plant for power generation from low-temperature geothermal sources

International Nuclear Information System (INIS)

Wang, Enhua; Yu, Zhibin

2016-01-01

Highlights: • A composition-adjustable Kalina cycle is analysed and presented. • An air-cooled condenser is used and thermodynamic performance is analysed. • Composition adjustment can improve system performance significantly. - Abstract: The Kalina cycle is believed to be one of the most promising technologies for power generation from low temperature heat sources such as geothermal energy. So far, most Kalina cycle power plants are designed with a working fluid mixture having a fixed composition, and thus normally operate at a fixed condensing temperature. However, the ambient temperature (i.e., heat sink) varies over a large range as the season changes over a year, particularly in continental climates. Recently, a new concept, i.e., composition-adjustable Kalina cycle, was proposed to develop power plants that can match their condensing temperature with the changing ambient conditions, aiming at improving the cycle’s overall thermal efficiency. However, no detailed analysis of its implementation and the potential benefits under various climate conditions has been reported. For this reason, this paper carried out a comprehensive numerical research on its implementation and performance analysis under several different climate conditions. A mathematical model is firstly established to simulate the working principle of a composition-adjustable Kalina cycle, based on which a numerical program is then developed to analyse the cycle’s performance under various climate conditions. The developed numerical model is verified with some published data. The dynamic composition adjustment in response to the changing ambient temperature is simulated to evaluate its effect on the plant’s performance over a year. The results show that a composition-adjustable Kalina cycle could achieve higher annual-average thermal efficiency than a conventional one with a fixed mixture composition. However, such an improvement of thermal efficiency strongly depends on the heat source

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.

Cycle layout studies of S-CO2 cycle for the next generation nuclear system application

International Nuclear Information System (INIS)

Ahn, Yoonhan; Bae, Seong Jun; Kim, Minseok; Cho, Seong Kuk; Baik, Seungjoon; Lee, Jeong Ik; Cha, Jae Eun

2014-01-01

According to the second law of thermodynamics, the next generation nuclear reactor system efficiency can potentially be increased with higher operating temperature. Fig.1 shows several power conversion system efficiencies and heat sources with respect to the system top operating temperature. As shown in Fig.1, the steam Rankine and gas Brayton cycles have been considered as the major power conversion systems more than several decades. In the next generation reactor operating temperature region (450 - 900 .deg. C), the steam Rankine and gas Brayton cycles have limits due to material problems and low efficiency, respectively. Among the future power conversion systems, S-CO 2 cycle is receiving interests due to several benefits including high efficiency under the mild turbine inlet temperature range (450-650 .deg. C), compact turbomachinery and simple layout compared to the steam Rankine cycle. S-CO 2 cycle can show relatively high efficiency under the mild turbine inlet temperature range (450-600 .deg. C) compared to other power conversion systems. The recompression cycle shows the best efficiency among other layouts and it is suitable for the application to advanced nuclear reactor systems. As S-CO 2 cycle performance can vary depending on the layout configuration, further studies on the layouts are required to design a better performing cycle

Hybrid cycles for micro generation

International Nuclear Information System (INIS)

Campanari, S.

2000-01-01

This paper deals with the main features of two emerging technologies in the field of small-scale power generation, micro turbines and Solid Oxide Fuel Cells, discussing the extremely high potential of their combination into hybrid cycles and their possible role for distributed cogeneration [it

Power generation enhancement in a salinity-gradient solar pond power plant using thermoelectric generator

International Nuclear Information System (INIS)

Ziapour, Behrooz M.; Saadat, Mohammad; Palideh, Vahid; Afzal, Sadegh

2017-01-01

Highlights: • Thermoelectric generator was used and simulated within a salinity-gradient solar pond power plant. • Results showed that the thermoelectric generator can be able to enhance the power plant efficiency. • Results showed that the presented models can be able to produce generation even in the cold months. • The optimum size of area of solar pond based on its effect on efficiency is 50,000 m 2 . - Abstract: Salinity-gradient solar pond (SGSP) has been a reliable supply of heat source for power generation when it has been integrated with low temperature thermodynamics cycles like organic Rankine cycle (ORC). Also, thermoelectric generator (TEG) plays a critical role in the production of electricity from renewable energy sources. This paper investigates the potential of thermoelectric generator as a power generation system using heat from SGSP. In this work, thermoelectric generator was used instead of condenser of ORC with the purpose of improving the performance of system. Two new models of SGSP have been presented as: (1) SGSP using TEG in condenser of ORC without heat exchanger and (2) SGSP using TEG in condenser of ORC with heat exchanger. These proposed systems was evaluated through computer simulations. The ambient conditions were collected from beach of Urmia lake in IRAN. Simulation results indicated that, for identical conditions, the model 1 has higher performance than other model 2. For models 1 and 2 in T LCZ = 90 °C, the overall thermal efficiency of the solar pond power plant, were obtained 0.21% and 0.2% more than ORC without TEG, respectively.

Optimizing an advanced hybrid of solar-assisted supercritical CO2 Brayton cycle: A vital transition for low-carbon power generation industry

International Nuclear Information System (INIS)

Milani, Dia; Luu, Minh Tri; McNaughton, Robbie; Abbas, Ali

2017-01-01

Highlights: • The layout of 14 demonstrative supercritical CO 2 closed Brayton cycles are analysed. • The key parameters of the “combined” cycle are sensitized and optimized. • The effect of thermal efficiency vs HX area on techno-economic nexus is highlighted. • The design of a matching solar heliostat field in direct configuration is revealed. • The water demand for hybrid vs water-only cooling scenarios are assessed. - Abstract: Current worldwide infrastructure of electrical power generation would mostly continue to rely on fossil-fuel but require a modest transition for the ultimate goal of decarbonizing power generation industry. By relying on those already established and carefully managed centrepiece power plants (PPs), we aim at filling the deficits of the current electrical networks with smaller, cleaner, and also more efficient PPs. In this context, we present a unique model for a small-scale decentralized solar-assisted supercritical CO 2 closed Brayton cycle (sCO 2 -CBC). Our model is based on the optimized values of three key performance indicators (KPIs); thermal efficiency, concentrated solar power (CSP) compatibility, and water demand for cooling. For a case-study of 10 MW e CSP-assisted sCO 2 -CBC power plant, our dynamic model shows a 52.7% thermal efficiency and 25.9% solar penetration and up to 80% of water saving in heat-rejection units. These KPIs show significant promise of the solar-assisted supercritical CO 2 power cycle for an imperative transformation in the power industry towards future sustainable electricity generation.

Performance of ammonia–water based cycles for power generation from low enthalpy heat sources

International Nuclear Information System (INIS)

Mergner, Hanna; Weimer, Thomas

2015-01-01

Cost efficient power generation from low temperature heat sources requires an optimal usage of the available heat. In addition to the ORC (Organic Rankine Cycles), cycles with ammonia and water as working fluid show promising results regarding efficiency. Due to their non-isothermal phase change, mixtures can adapt well to a liquid heat source temperature profile and reduce the exergetic losses. In this analysis thermodynamic calculations on the layouts of two existing ammonia–water cycles are compared: a geothermal power plant based on a Siemens’ patent and a modified lab plant based on a patent invented by Kalina (KCS-34). The difference between the two cycles is the position of the internal heat recovery. Cycle simulations were carried out at defined boundary conditions in order to identify optimal operation parameters. For the selected heat source of 393.15 K (hot water) the ammonia mass fraction between 80% and 90% results in the best performance in both configurations. In general, the layout of Siemens achieves a slightly better efficiency compared to the KCS-34. Compared to an ORC using R245fa as working fluid, the exergetic efficiency can be increased by the ammonia/water based cycles by approximately 25%. - Highlights: • Two NH 3 /H 2 O based cycles based on existing plants are analyzed and compared. • A simple KCS-34 focuses on a high enthalpy difference at the turbine. • The Kalina cycle of a Siemens patent KC SG1 runs on a high vapor mass flow. • The layout of the KC SG1 shows slightly better results compared to the KCS-34. • NH 3 /H 2 O cycles show an efficiency increase compared to a regular ORC with R245fa

The Researches on Cycle-Changeable Generation Settlement Method

Science.gov (United States)

XU, Jun; LONG, Suyan; LV, Jianhu

2018-03-01

Through the analysis of the business characteristics and problems of price adjustment, a cycle-changeable generation settlement method is proposed to support any time cycle settlement, and put forward a complete set of solutions, including the creation of settlement tasks, time power dismantle, generating fixed cycle of electricity, net energy split. At the same time, the overall design flow of cycle-changeable settlement is given. This method supports multiple price adjustments during the month, and also is an effective solution to the cost reduction of month-after price adjustment.

The future of integrated coal gasification combined cycle power plants

International Nuclear Information System (INIS)

Mueller, R.; Termuehlen, H.

1991-01-01

This paper examines the future of integrated coal gasification combined cycle (IGCC) power plants as affected by various technical, economical and environmental trends in power generation. The topics of the paper include a description of natural gas-fired combined cycle power plants, IGCC plants, coal gasifier concepts, integration of gasifiers into combined cycle power plants, efficiency, environmental impacts, co-products of IGCC power plants, economics of IGCC power plants, and a review of IGCC power plant projects

Life-cycle comparison of greenhouse gas emissions and water consumption for coal and shale gas fired power generation in China

International Nuclear Information System (INIS)

Chang, Yuan; Huang, Runze; Ries, Robert J.; Masanet, Eric

2015-01-01

China has the world's largest shale gas reserves, which might enable it to pursue a new pathway for electricity generation. This study employed hybrid LCI (life cycle inventory) models to quantify the ETW (extraction-to-wire) GHG (greenhouse gas) emissions and water consumption per kWh of coal- and shale gas-fired electricity in China. Results suggest that a coal-to-shale gas shift and upgrading coal-fired power generation technologies could provide pathways to less GHG and water intensive power in China. Compared to different coal-fired generation technologies, the ETW GHG emissions intensity of gas-fired CC (combined cycle) technology is 530 g CO 2 e/kWh, which is 38–45% less than China's present coal-fired electricity. Gas-fired CT (combustion turbine) technology has the lowest ETW water consumption intensity at 960 g/kWh, which is 34–60% lower than China's present coal-fired electricity. The GHG-water tradeoff of the two gas-fired power generation technologies suggests that gas-fired power generation technologies should be selected based on regional-specific water resource availabilities and electricity demand fluctuations in China. However, the low price of coal-fired electricity, high cost of shale gas production, insufficient pipeline infrastructures, and multiple consumers of shale gas resources may serve as barriers to a coal-to-shale gas shift in China's power sector in the near term. - Highlights: • The GHG and water footprints of coal- and shale gas-fired electricity are estimated. • A coal-to-shale gas shift can enable less GHG and water intensive power in China. • The GHG emissions of shale gas-fired combined cycle technology is 530 g CO 2 e/kWh. • The water consumption of shale gas-fired combustion turbine technology is 960 g/kWh. • Shale gas-fired power generation technologies selection should be regional-specific

53 W average power few-cycle fiber laser system generating soft x rays up to the water window.

Science.gov (United States)

Rothhardt, Jan; Hädrich, Steffen; Klenke, Arno; Demmler, Stefan; Hoffmann, Armin; Gotschall, Thomas; Eidam, Tino; Krebs, Manuel; Limpert, Jens; Tünnermann, Andreas

2014-09-01

We report on a few-cycle laser system delivering sub-8-fs pulses with 353 μJ pulse energy and 25 GW of peak power at up to 150 kHz repetition rate. The corresponding average output power is as high as 53 W, which represents the highest average power obtained from any few-cycle laser architecture so far. The combination of both high average and high peak power provides unique opportunities for applications. We demonstrate high harmonic generation up to the water window and record-high photon flux in the soft x-ray spectral region. This tabletop source of high-photon flux soft x rays will, for example, enable coherent diffractive imaging with sub-10-nm resolution in the near future.

Nuclear power generation cost methodology

International Nuclear Information System (INIS)

Delene, J.G.; Bowers, H.I.

1980-08-01

A simplified calculational procedure for the estimation of nuclear power generation cost is outlined. The report contains a discussion of the various components of power generation cost and basic equations for calculating that cost. An example calculation is given. The basis of the fixed-charge rate, the derivation of the levelized fuel cycle cost equation, and the heavy water charge rate are included as appendixes

Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

Science.gov (United States)

2016-08-01

efficiency by reducing energy consumption associated with electrical generation and reduces greenhouse gas emissions by increasing electrical generating...integrated system fuel economy test conditions This computation requires prediction of fuel consumption over baseline and integrated system load...EW-201251) Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

Modeling of Turbine Cycles Using a Neuro-Fuzzy Based Approach to Predict Turbine-Generator Output for Nuclear Power Plants

Directory of Open Access Journals (Sweden)

Yea-Kuang Chan

2012-01-01

Full Text Available Due to the very complex sets of component systems, interrelated thermodynamic processes and seasonal change in operating conditions, it is relatively difficult to find an accurate model for turbine cycle of nuclear power plants (NPPs. This paper deals with the modeling of turbine cycles to predict turbine-generator output using an adaptive neuro-fuzzy inference system (ANFIS for Unit 1 of the Kuosheng NPP in Taiwan. Plant operation data obtained from Kuosheng NPP between 2006 and 2011 were verified using a linear regression model with a 95% confidence interval. The key parameters of turbine cycle, including turbine throttle pressure, condenser backpressure, feedwater flow rate and final feedwater temperature are selected as inputs for the ANFIS based turbine cycle model. In addition, a thermodynamic turbine cycle model was developed using the commercial software PEPSE® to compare the performance of the ANFIS based turbine cycle model. The results show that the proposed ANFIS based turbine cycle model is capable of accurately estimating turbine-generator output and providing more reliable results than the PEPSE® based turbine cycle models. Moreover, test results show that the ANFIS performed better than the artificial neural network (ANN, which has also being tried to model the turbine cycle. The effectiveness of the proposed neuro-fuzzy based turbine cycle model was demonstrated using the actual operating data of Kuosheng NPP. Furthermore, the results also provide an alternative approach to evaluate the thermal performance of nuclear power plants.

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)

Membranes for H2 generation from nuclear powered thermochemical cycles

International Nuclear Information System (INIS)

Nenoff, Tina Maria; Ambrosini, Andrea; Garino, Terry J.; Gelbard, Fred; Leung, Kevin; Navrotsky, Alexandra; Iyer, Ratnasabapathy G.; Axness, Marlene

2006-01-01

In an effort to produce hydrogen without the unwanted greenhouse gas byproducts, high-temperature thermochemical cycles driven by heat from solar energy or next-generation nuclear power plants are being explored. The process being developed is the thermochemical production of Hydrogen. The Sulfur-Iodide (SI) cycle was deemed to be one of the most promising cycles to explore. The first step of the SI cycle involves the decomposition of H 2 SO 4 into O 2 , SO 2 , and H 2 O at temperatures around 850 C. In-situ removal of O 2 from this reaction pushes the equilibrium towards dissociation, thus increasing the overall efficiency of the decomposition reaction. A membrane is required for this oxygen separation step that is capable of withstanding the high temperatures and corrosive conditions inherent in this process. Mixed ionic-electronic perovskites and perovskite-related structures are potential materials for oxygen separation membranes owing to their robustness, ability to form dense ceramics, capacity to stabilize oxygen nonstoichiometry, and mixed ionic/electronic conductivity. Two oxide families with promising results were studied: the double-substituted perovskite A x Sr 1-x Co 1-y B y O 3-δ (A=La, Y; B=Cr-Ni), in particular the family La x Sr 1-x Co 1-y Mn y O 3-δ (LSCM), and doped La 2 Ni 1-x M x O 4 (M = Cu, Zn). Materials and membranes were synthesized by solid state methods and characterized by X-ray and neutron diffraction, SEM, thermal analyses, calorimetry and conductivity. Furthermore, we were able to leverage our program with a DOE/NE sponsored H 2 SO 4 decomposition reactor study (at Sandia), in which our membranes were tested in the actual H 2 SO 4 decomposition step

How to quantify uncertainty and variability in life cycle assessment: the case of greenhouse gas emissions of gas power generation in the US

Science.gov (United States)

Hauck, M.; Steinmann, Z. J. N.; Laurenzi, I. J.; Karuppiah, R.; Huijbregts, M. A. J.

2014-07-01

This study quantified the contributions of uncertainty and variability to the range of life-cycle greenhouse gas (LCGHG) emissions associated with conventional gas-fired electricity generation in the US. Whereas uncertainty is defined as lack of knowledge and can potentially be reduced by additional research, variability is an inherent characteristic of supply chains and cannot be reduced without physically modifying the system. The life-cycle included four stages: production, processing, transmission and power generation, and utilized a functional unit of 1 kWh of electricity generated at plant. Technological variability requires analyses of life cycles of individual power plants, e.g. combined cycle plants or boilers. Parameter uncertainty was modeled via Monte Carlo simulation. Our approach reveals that technological differences are the predominant cause for the range of LCGHG emissions associated with gas power, primarily due to variability in plant efficiencies. Uncertainties in model parameters played a minor role for 100 year time horizon. Variability in LCGHG emissions was a factor of 1.4 for combined cycle plants, and a factor of 1.3 for simple cycle plants (95% CI, 100 year horizon). The results can be used to assist decision-makers in assessing factors that contribute to LCGHG emissions despite uncertainties in parameters employed to estimate those emissions.

How to quantify uncertainty and variability in life cycle assessment: the case of greenhouse gas emissions of gas power generation in the US

International Nuclear Information System (INIS)

Hauck, M; Steinmann, Z J N; Huijbregts, M A J; Laurenzi, I J; Karuppiah, R

2014-01-01

This study quantified the contributions of uncertainty and variability to the range of life-cycle greenhouse gas (LCGHG) emissions associated with conventional gas-fired electricity generation in the US. Whereas uncertainty is defined as lack of knowledge and can potentially be reduced by additional research, variability is an inherent characteristic of supply chains and cannot be reduced without physically modifying the system. The life-cycle included four stages: production, processing, transmission and power generation, and utilized a functional unit of 1 kWh of electricity generated at plant. Technological variability requires analyses of life cycles of individual power plants, e.g. combined cycle plants or boilers. Parameter uncertainty was modeled via Monte Carlo simulation. Our approach reveals that technological differences are the predominant cause for the range of LCGHG emissions associated with gas power, primarily due to variability in plant efficiencies. Uncertainties in model parameters played a minor role for 100 year time horizon. Variability in LCGHG emissions was a factor of 1.4 for combined cycle plants, and a factor of 1.3 for simple cycle plants (95% CI, 100 year horizon). The results can be used to assist decision-makers in assessing factors that contribute to LCGHG emissions despite uncertainties in parameters employed to estimate those emissions. (letter)

Life cycle assessment of grid-connected photovoltaic power generation from crystalline silicon solar modules in China

International Nuclear Information System (INIS)

Hou, Guofu; Sun, Honghang; Jiang, Ziying; Pan, Ziqiang; Wang, Yibo; Zhang, Xiaodan; Zhao, Ying; Yao, Qiang

2016-01-01

Graphical abstract: Comparison of life cycle GHG emissions of various power sources. - Highlights: • The LCA study of grid-connected PV generation with silicon solar modules in China has been performed. • The energy payback times range from 1.6 to 2.3 years. • The GHG emissions are in the range of 60.1–87.3 g-CO_2,eq/kW h. • The PV manufacturing process occupied about 85% or higher of total energy usage and total GHG emission. • The SoG-Si production process accounted for more than 35% of total energy consumption and GHG emissions. - Abstract: The environmental impacts of grid-connected photovoltaic (PV) power generation from crystalline silicon (c-Si) solar modules in China have been investigated using life cycle assessment (LCA). The life cycle inventory was first analyzed. Then the energy consumption and greenhouse gas (GHG) emission during every process were estimated in detail, and finally the life-cycle value was calculated. The results showed that the energy payback time (T_E_P_B_T) of grid-connected PV power with crystalline silicon solar modules ranges from 1.6 to 2.3 years, while the GHG emissions now range from 60.1 to 87.3 g-CO_2,eq/kW h depending on the installation methods. About 84% or even more of the total energy consumption and total GHG emission occupied during the PV manufacturing process. The solar grade silicon (SoG-Si) production is the most energy-consuming and GHG-emitting process, which accounts for more than 35% of the total energy consumption and the total GHG emission. The results presented in this study are expected to provide useful information to enact reasonable policies, development targets, as well as subsidies for PV technology in China.

An update technology for integrated biomass gasification combined cycle power plant

International Nuclear Information System (INIS)

Bhattacharya, P.; Dey, S.

2014-01-01

A discussion is presented on the technical analysis of a 6.4 M W_e integrated biomass gasification combined cycle (IBGCC) plant. It features three numbers of downdraft biomass gasifier systems with suitable gas clean-up trains, three numbers of internal combustion (IC) producer gas engines for producing 5.85 MW electrical power in open cycle and 550 kW power in a bottoming cycle using waste heat. Comparing with IC gas engine single cycle systems, this technology route increases overall system efficiency of the power plant, which in turn improves plant economics. Estimated generation cost of electricity indicates that mega-watt scale IBGCC power plants can contribute to good economies of scale in India. This paper also highlight's the possibility of activated carbon generation from the char, a byproduct of gasification process, and use of engine's jacket water heat to generate chilled water through VAM for gas conditioning. (author)

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

International Nuclear Information System (INIS)

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

1999-01-01

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

Marginal Generation Technology in the Chinese Power Market towards 2030 Based on Consequential Life Cycle Assessment

DEFF Research Database (Denmark)

Zhao, Guangling; Guerrero, Josep M.; Pei, Yingying

2016-01-01

Electricity consumption is often the hotspot of life cycle assessment (LCA) of products, industrial activities, or services. The objective of this paper is to provide a consistent, scientific, region-specific electricity-supply-based inventory of electricity generation technology for national...... and regional power grids. Marginal electricity generation technology is pivotal in assessing impacts related to additional consumption of electricity. China covers a large geographical area with regional supply grids; these are arguably equally or less integrated. Meanwhile, it is also a country with internal...

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)

Shengjun, Zhang; Huaixin, Wang; Tao, Guo

2011-01-01

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 o C) 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 CO 2 is reduced per year when the LEC value is used as

Modeling of a combined cycle power plant

International Nuclear Information System (INIS)

Faridah Mohamad Idris

2001-01-01

The combined cycle power plant is a non-linear, closed loop system, which consists of high-pressure (HP) superheater, HP evaporator, HP economizer, low-pressure (LP) evaporator, HP drum, HP deaerator, condenser, HP and LP steam turbine and gas turbine. The two types of turbines in the plant for example the gas turbine and the HP and LP steam turbines operate concurrently to generate power to the plant. The exhaust gas which originate from the combustion chamber drives the gas turbine, after which it flows into the heat recovery steam generator (HRSG) to generate superheated steam to be used in driving the HP and LP steam turbines. In this thesis, the combined cycle power plant is modeled at component level using the physical method. Assuming that there is delay in transport, except for the gas turbine system, the mass and heat balances are applied on the components of the plant to derive the governing equations of the components. These time dependent equations, which are of first order differential types, are then solved for the mass and enthalpy of the components. The solutions were simulated using Matlab Simulink using measured plant data. Where necessary there is no plant data available, approximated data were used. The generalized regression neural networks are also used to generate extra sets of simulation data for the HRSG system. Comparisons of the simulation results with its corresponding plant data showed good agreements between the two and indicated that the models developed for the components could be used to represent the combined cycle power plant under study. (author)

Study Of The Fuel Cycle Effect To The Electricity Generating Cost

International Nuclear Information System (INIS)

Salimy, D. H.

1998-01-01

The nuclear fuel cycle cost contributes relatively small fraction to the total nuclear power generation cost, I.e. about 15 to 30%, compared to the fuel cost in the coal-generated electricity (40-60%). Or in the oil-generated electricity (70-80%). This situation will give effect that the future generation cost is much less sensitive to the changes in the fuel prince than in the case of fossil fuel power plants. The study has shown that by assuming a 100% increase in the natural uranium price, the total nuclear fuel cycle cost would increase only by about 27% and in turn it contributes about 29% increase to the total nuclear fuel cycle cost. As a result, it contributes only 4 to 8% increase in the nuclear energy generation cost. As a comparison, if the same situation should occur to fossil fuel plants, the assumed fuel price increase would have increased the electricity generating cost by about 40-65% for coal-fired plants, and about 70-85% for oil-fired plants. This study also has assesses the economic aspects of the electricity generating cots for nuclear power plant (NPP) and the coal power plant. For an NPP the most affecting factor is the investment cost, while for the coal power plant, the major factor influencing the total cost is the price/cost of the fuel

Thermodynamic Analysis of a Supercritical Mercury Power Cycle

Energy Technology Data Exchange (ETDEWEB)

Roberts, Jr, A S

1969-04-15

An heat engine is considered which employs supercritical mercury as the working fluid and a magnetohydrodynamic (MHD) generator for thermal to electrical energy conversion. The main thrust of the paper is power cycle thermodynamics, where constraints are imposed by utilizing a MHD generator operating between supercritical, electrically conducting states of the working fluid; and, pump work is accomplished with liquid mercury. The temperature range is approximately 300 to 2200 K and system pressure is > 1,500 atm. Equilibrium and transport properties are carefully considered since these are known to vary radically in the vicinity of the critical point, which is found near the supercritical states of interest. A maximum gross plant efficiency is 20% with a regenerator effectiveness of 90% and greater, a cycle pressure ratio of two, and with highly efficient pump and generator. Certain specified cycle irreversibilities and others such as heat losses and heat exchanger pressure drops, which are not accounted for explicitly, reduce the gross plant efficiency to a few per cent. Experimental efforts aimed at practical application of the power cycle are discouraged by the marginal thermodynamic performance predicted by this study, unless such applications are insensitive to gross cycle efficiency.

Thermodynamic Analysis of a Supercritical Mercury Power Cycle

International Nuclear Information System (INIS)

Roberts, A.S. Jr.

1969-04-01

An heat engine is considered which employs supercritical mercury as the working fluid and a magnetohydrodynamic (MHD) generator for thermal to electrical energy conversion. The main thrust of the paper is power cycle thermodynamics, where constraints are imposed by utilizing a MHD generator operating between supercritical, electrically conducting states of the working fluid; and, pump work is accomplished with liquid mercury. The temperature range is approximately 300 to 2200 K and system pressure is > 1,500 atm. Equilibrium and transport properties are carefully considered since these are known to vary radically in the vicinity of the critical point, which is found near the supercritical states of interest. A maximum gross plant efficiency is 20% with a regenerator effectiveness of 90% and greater, a cycle pressure ratio of two, and with highly efficient pump and generator. Certain specified cycle irreversibilities and others such as heat losses and heat exchanger pressure drops, which are not accounted for explicitly, reduce the gross plant efficiency to a few per cent. Experimental efforts aimed at practical application of the power cycle are discouraged by the marginal thermodynamic performance predicted by this study, unless such applications are insensitive to gross cycle efficiency

Development of water demand coefficients for power generation from renewable energy technologies

International Nuclear Information System (INIS)

Ali, Babkir; Kumar, Amit

2017-01-01

Highlights: • Water consumption and withdrawals coefficients for renewable power generation were developed. • Six renewable energy sources (biomass, nuclear, solar, wind, hydroelectricity, and geothermal) were studied. • Life cycle water footprints for 60 electricity generation pathways were considered. • Impact of cooling systems for some power generation pathways was assessed. - Abstract: Renewable energy technology-based power generation is considered to be environmentally friendly and to have a low life cycle greenhouse gas emissions footprint. However, the life cycle water footprint of renewable energy technology-based power generation needs to be assessed. The objective of this study is to develop life cycle water footprints for renewable energy technology-based power generation pathways. Water demand is evaluated through consumption and withdrawals coefficients developed in this study. Sixty renewable energy technology-based power generation pathways were developed for a comprehensive comparative assessment of water footprints. The pathways were based on the use of biomass, nuclear, solar, wind, hydroelectricity, and geothermal as the source of energy. During the complete life cycle, power generation from bio-oil extracted from wood chips, a biomass source, was found to have the highest water demand footprint and wind power the lowest. During the complete life cycle, the water demand coefficients for biomass-based power generation pathways range from 260 to 1289 l of water per kilowatt hour and for nuclear energy pathways from 0.48 to 179 l of water per kilowatt hour. The water demand for power generation from solar energy-based pathways ranges from 0.02 to 4.39 l of water per kilowatt hour, for geothermal pathways from 0.04 to 1.94 l of water per kilowatt hour, and for wind from 0.005 to 0.104 l of water per kilowatt hour. A sensitivity analysis was conducted with varying conversion efficiencies to evaluate the impact of power plant performance on

Optimization of the triple-pressure combined cycle power plant

Directory of Open Access Journals (Sweden)

Alus Muammer

2012-01-01

Full Text Available The aim of this work was to develop a new system for optimization of parameters for combined cycle power plants (CCGTs with triple-pressure heat recovery steam generator (HRSG. Thermodynamic and thermoeconomic optimizations were carried out. The objective of the thermodynamic optimization is to enhance the efficiency of the CCGTs and to maximize the power production in the steam cycle (steam turbine gross power. Improvement of the efficiency of the CCGT plants is achieved through optimization of the operating parameters: temperature difference between the gas and steam (pinch point P.P. and the steam pressure in the HRSG. The objective of the thermoeconomic optimization is to minimize the production costs per unit of the generated electricity. Defining the optimal P.P. was the first step in the optimization procedure. Then, through the developed optimization process, other optimal operating parameters (steam pressure and condenser pressure were identified. The developed system was demonstrated for the case of a 282 MW CCGT power plant with a typical design for commercial combined cycle power plants. The optimized combined cycle was compared with the regular CCGT plant.

Optimization in the scale of nuclear power generation and the economy of nuclear power

International Nuclear Information System (INIS)

Suzuki, Toshiharu

1983-01-01

In the not too distant future, the economy of nuclear power will have to be restudied. Various conditions and circumstances supporting this economy of nuclear power tend to change, such as the decrease in power demand and supply, the diversification in base load supply sources, etc. The fragility in the economic advantage of nuclear power may thus be revealed. In the above connection, on the basis of the future outlook of the scale of nuclear power generation, that is, the further reduction of the current nuclear power program, and of the corresponding supply and demand of nuclear fuel cycle quantities, the aspect of the economic advantage of nuclear power was examined, for the purpose of optimizing the future scale of nuclear power generation (the downward revision of the scale, the establishment of the schedule of nuclear fuel cycle the stagnation of power demand and nuclear power generation costs). (Mori, K.)

Power cycles with ammonia-water mixtures as working fluid

Energy Technology Data Exchange (ETDEWEB)

Thorin, Eva

2000-05-01

It is of great interest to improve the efficiency of power generating processes, i.e. to convert more of the energy in the heat source to power. This is favorable from an environmental point of view and can also be an economic advantage. To use an ammonia-water mixture instead of water as working fluid is a possible way to improve the efficiency of steam turbine processes. This thesis includes studies of power cycles with ammonia-water mixtures as working fluid utilizing different kinds of heat sources for power and heat generation. The thermophysical properties of the mixture are also studied. They play an important role in the calculations of the process performance and for the design of its components, such as heat exchangers. The studies concern thermodynamic simulations of processes in applications suitable for Swedish conditions. Available correlations for the thermophysical properties are compared and their influence on simulations and heat exchanger area predictions is investigated. Measurements of ammonia-water mixture viscosities using a vibrating wire viscometer are also described. The studies performed show that power cycles with ammonia-water mixtures as the working fluid are well suited for utilization of waste heat from industry and from gas engines. The ammonia-water power cycles can give up to 32 % more power in the industrial waste heat application and up to 54 % more power in the gas engine bottoming cycle application compared to a conventional Rankine steam cycle. However, ammonia-water power cycles in small direct-fired biomass-fueled cogeneration plants do not show better performance than a conventional Rankine steam cycle. When different correlations for the thermodynamic properties are used in simulations of a simple ammonia-water power cycle the difference in efficiency is not larger than 4 %, corresponding to about 1.3 percentage points. The differences in saturation properties between the correlations are, however, considerable at high

Efficiency Study of a Commercial Thermoelectric Power Generator (TEG) Under Thermal Cycling

Science.gov (United States)

Hatzikraniotis, E.; Zorbas, K. T.; Samaras, I.; Kyratsi, Th.; Paraskevopoulos, K. M.

2010-09-01

Thermoelectric generators (TEGs) make use of the Seebeck effect in semiconductors for the direct conversion of heat to electrical energy. The possible use of a device consisting of numerous TEG modules for waste heat recovery from an internal combustion (IC) engine could considerably help worldwide efforts towards energy saving. However, commercially available TEGs operate at temperatures much lower than the actual operating temperature range in the exhaust pipe of an automobile, which could cause structural failure of the thermoelectric elements. Furthermore, continuous thermal cycling could lead to reduced efficiency and lifetime of the TEG. In this work we investigate the long-term performance and stability of a commercially available TEG under temperature and power cycling. The module was subjected to sequential hot-side heating (at 200°C) and cooling for long times (3000 h) in order to measure changes in the TEG’s performance. A reduction in Seebeck coefficient and an increase in resistivity were observed. Alternating-current (AC) impedance measurements and scanning electron microscope (SEM) observations were performed on the module, and results are presented and discussed.

Thermodynamic assessment of integrated biogas-based micro-power generation system

International Nuclear Information System (INIS)

Hosseini, Seyed Ehsan; Barzegaravval, Hasan; Wahid, Mazlan Abdul; Ganjehkaviri, Abdolsaeid; Sies, Mohsin Mohd

2016-01-01

Highlights: • A thermodynamic modelling of an integrated biogas-based micro-power generation system is reported. • The impact of design parameters on the thermodynamic performance of the system is evaluated. • High turbine inlet temperatures lead the system to the higher energy and exergy efficiency and higher power generation. • Enhancement of GT isentropic efficiency incurs negative effects on the performance of air preheater and heat exchanger. • The rate of power generation increases by the enhancement of steam turbine pressure in ORC. - Abstract: In this paper, a thermodynamic modelling of an integrated biogas (60%CH_4 + 40%CO_2) micro-power generation system for electricity generation is reported. This system involves a gas turbine cycle and organic Rankine cycle (ORC) where the wasted heat of gas turbine cycle is recovered by closed ORC. The net output power of the micro-power generation system is fixed at 1.4 MW includes 1 MW power generated by GT and 0.4 MW by ORC. Energy and exergy assessments and related parametric studies are carried out, and parameters that influence on energy and exergy efficiency are evaluated. The performance of the system with respect to variation of design parameters such as combustion air inlet temperature, turbine inlet temperature, compressor pressure ratio, gas turbine isentropic efficiency and compressor isentropic efficiency (from the top cycle) and steam turbine inlet pressure, and condenser pressure (from bottoming cycle) is evaluated. The results reveal that by the increase of gas turbine isentropic efficiency, the outlet temperature of gas turbine decreases which incurs negative impacts on the performance of air preheater and heat exchanger, however the energy and exergy efficiency increases in the whole system. By the increase of air compressor pressure ratio, the energy and exergy of the combined cycle decreases. The exergy efficiency of ORC alters by the variation of gas turbine parameters which can be

Membranes for H2 generation from nuclear powered thermochemical cycles.

Energy Technology Data Exchange (ETDEWEB)

Nenoff, Tina Maria; Ambrosini, Andrea; Garino, Terry J.; Gelbard, Fred; Leung, Kevin; Navrotsky, Alexandra (University of California, Davis, CA); Iyer, Ratnasabapathy G. (University of California, Davis, CA); Axness, Marlene

2006-11-01

In an effort to produce hydrogen without the unwanted greenhouse gas byproducts, high-temperature thermochemical cycles driven by heat from solar energy or next-generation nuclear power plants are being explored. The process being developed is the thermochemical production of Hydrogen. The Sulfur-Iodide (SI) cycle was deemed to be one of the most promising cycles to explore. The first step of the SI cycle involves the decomposition of H{sub 2}SO{sub 4} into O{sub 2}, SO{sub 2}, and H{sub 2}O at temperatures around 850 C. In-situ removal of O{sub 2} from this reaction pushes the equilibrium towards dissociation, thus increasing the overall efficiency of the decomposition reaction. A membrane is required for this oxygen separation step that is capable of withstanding the high temperatures and corrosive conditions inherent in this process. Mixed ionic-electronic perovskites and perovskite-related structures are potential materials for oxygen separation membranes owing to their robustness, ability to form dense ceramics, capacity to stabilize oxygen nonstoichiometry, and mixed ionic/electronic conductivity. Two oxide families with promising results were studied: the double-substituted perovskite A{sub x}Sr{sub 1-x}Co{sub 1-y}B{sub y}O{sub 3-{delta}} (A=La, Y; B=Cr-Ni), in particular the family La{sub x}Sr{sub 1-x}Co{sub 1-y}Mn{sub y}O{sub 3-{delta}} (LSCM), and doped La{sub 2}Ni{sub 1-x}M{sub x}O{sub 4} (M = Cu, Zn). Materials and membranes were synthesized by solid state methods and characterized by X-ray and neutron diffraction, SEM, thermal analyses, calorimetry and conductivity. Furthermore, we were able to leverage our program with a DOE/NE sponsored H{sub 2}SO{sub 4} decomposition reactor study (at Sandia), in which our membranes were tested in the actual H{sub 2}SO{sub 4} decomposition step.

Regenerative Heater Optimization for Steam Turbo-Generation Cycles of Generation IV Nuclear Power Plants with a Comparison of Two Concepts for the Westinghouse International Reactor Innovative and Secure (IRIS)

International Nuclear Information System (INIS)

Williams, W.C.

2002-01-01

The intent of this study is to discuss some of the many factors involved in the development of the design and layout of a steam turbo-generation unit as part of a modular Generation IV nuclear power plant. Of the many factors involved in the design and layout, this research will cover feed water system layout and optimization issues. The research is arranged in hopes that it can be generalized to any Generation IV system which uses a steam powered turbo-generation unit. The research is done using the ORCENT-II heat balance codes and the Salisbury methodology to be reviewed herein. The Salisbury methodology is used on an original cycle design by Famiani for the Westinghouse IRIS and the effects due to parameter variation are studied. The vital parameters of the Salisbury methodology are the incremental heater surface capital cost (S) in $/ft 2 , the value of incremental power (I) in $/kW, and the overall heat transfer coefficient (U) in Btu/ft 2 -degrees Fahrenheit-hr. Each is varied in order to determine the effects on the cycles overall heat rate, output, as well as, the heater surface areas. The effects of each are shown. Then the methodology is then used to compare the optimized original Famiani design consisting of seven regenerative feedwater heaters with an optimized new cycle concept, INRC8, containing four regenerative heaters. The results are shown. It can be seen that a trade between the complexity of the seven stage regenerative Famiani cycle and the simplicity of the INRC8 cycle can be made. It is desired that this methodology can be used to show the ability to evaluate modularity through the value of size a complexity of the system as well as the performance. It also shows the effectiveness of the Salisbury methodology in the optimization of regenerative cycles for such an evaluation

Pressurized fluidized bed combustion combined cycle power plant with coal gasification: Second generation pilot plant

International Nuclear Information System (INIS)

Farina, G.L.; Bressan, L.

1991-01-01

This paper presents the technical and economical background of a research and development program of a novel power generation scheme, which is based on coal gasification, pressurized fluid bed combustion and combined cycles. The participants in this program are: Foster Wheeler (project leader), Westinghouse, IGT and the USA Dept. of Energy. The paper describes the characteristics of the plant, the research program in course of implementation, the components of the pilot plant and the first results obtained

LPGC, Levelized Steam Electric Power Generator Cost

International Nuclear Information System (INIS)

Coen, J.J.; Delene, J.G.

1994-01-01

1 - Description of program or function: LPGC is a set of nine microcomputer programs for estimating power generation costs for large steam-electric power plants. These programs permit rapid evaluation using various sets of economic and technical ground rules. The levelized power generation costs calculated may be used to compare the relative economics of nuclear and coal-fired plants based on life-cycle costs. Cost calculations include capital investment cost, operation and maintenance cost, fuel cycle cost, decommissioning cost, and total levelized power generation cost. These programs can be used for quick analyses of power generation costs using alternative economic parameters, such as interest rate, escalation rate, inflation rate, plant lead times, capacity factor, fuel prices, etc. The two major types of electric generating plants considered are pressurized-water reactor (PWR) and pulverized coal-fired plants. Data are also provided for the Large Scale Prototype Breeder (LSPB) type liquid metal reactor. Costs for plant having either one or two units may be obtained. 2 - Method of solution: LPGC consists of nine individual menu-driven programs controlled by a driver program, MAINPWR. The individual programs are PLANTCAP, for calculating capital investment costs; NUCLOM, for determining operation and maintenance (O and M) costs for nuclear plants; COALOM, for computing O and M costs for coal-fired plants; NFUEL, for calculating levelized fuel costs for nuclear plants; COALCOST, for determining levelized fuel costs for coal-fired plants; FCRATE, for computing the fixed charge rate on the capital investment; LEVEL, for calculating levelized power generation costs; CAPITAL, for determining capitalized cost from overnight cost; and MASSGEN, for generating, deleting, or changing fuel cycle mass balance data for use with NFUEL. LPGC has three modes of operation. In the first, each individual code can be executed independently to determine one aspect of the total

A comparative analysis of rankine and absorption power cycles from exergoeconomic viewpoint

International Nuclear Information System (INIS)

Shokati, Naser; Ranjbar, Faramarz; Yari, Mortaza

2014-01-01

Highlights: • The Rankine and absorption power cycles are compared from exergoeconomic viewpoint. • The LiBr–H 2 O cycle has the highest unit cost of electricity produced by turbine. • The LiBr–H 2 O cycle has the lowest exergy destruction cost rate. • In LiBr–H 2 O cycle, the generator has the maximum value regarding (C-dot) D,k +(C-dot) L,k +(Z-dot) k . - Abstract: In this paper LiBr–H 2 O and NH 3 –H 2 O absorption power cycles and Rankine cycle which produce 1 MW electrical power in same conditions of heat sources are compared from exergoeconomic point of view. Exergoeconomic analysis is performed using the specific exergy costing (SPECO) method. The results show that among these cycles, although the LiBr–H 2 O cycle has the highest first law efficiency, but unit cost of electricity produced by turbine for LiBr–H 2 O cycle is more than that for Rankine cycle. This value is lowest for the NH 3 –H 2 O cycle. Moreover, the NH 3 –H 2 O cycle has the highest and the LiBr–H 2 O cycle has the lowest exergy destruction cost rate. The generator, the absorber and the boiler in all considered cycles have the maximum value of sum of cost rate associated with capital investment, operating and maintenance, exergy destruction and exergy losses. Therefore, these components should be taken into consideration from exergoeconomic viewpoint. In parametric study, it is observed that in the constant generator temperature, as the generator pressure increases, unit cost of power produced by turbine for LiBr–H 2 O and Rankine cycles decreases. This value for Rankine cycle is lower than for LiBr–H 2 O cycle whereas Rankine cycle efficiency is less than the efficiency of LiBr–H 2 O cycle. Also, in LiBr–H 2 O cycle, at constant temperature of the generator, the value of exergy destruction cost rate is minimized and exergoeconomic factor is maximized at particular values of generator pressure and the more absorber pressure results the minimum value of

Specification of life cycle assessment in nuclear power plants

International Nuclear Information System (INIS)

Abbaspour, M.; Kargari, N.; Mastouri, R.

2008-01-01

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 c radle to grave a pproach. 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

Generation of a single-cycle optical pulse

International Nuclear Information System (INIS)

Shverdin, M.Y.; Walker, D.R.; Yavuz, D.D.; Yin, G.Y.; Harris, S.E.

2005-01-01

We make use of coherent control of four-wave mixing to the ultraviolet as a diagnostic and describe the generation of a periodic optical waveform where the spectrum is sufficiently broad that the envelope is approximately a single-cycle in length, and where the temporal shape of this envelope may be synthesized by varying the coefficients of a Fourier series. Specifically, using seven sidebands, we report the generation of a train of single-cycle optical pulses with a pulse width of 1.6 fs, a pulse separation of 11 fs, and a peak power of 1 MW

Marginal Generation Technology in the Chinese Power Market towards 2030 Based on Consequential Life Cycle Assessment

Directory of Open Access Journals (Sweden)

Guangling Zhao

2016-09-01

Full Text Available Electricity consumption is often the hotspot of life cycle assessment (LCA of products, industrial activities, or services. The objective of this paper is to provide a consistent, scientific, region-specific electricity-supply-based inventory of electricity generation technology for national and regional power grids. Marginal electricity generation technology is pivotal in assessing impacts related to additional consumption of electricity. China covers a large geographical area with regional supply grids; these are arguably equally or less integrated. Meanwhile, it is also a country with internal imbalances in regional energy supply and demand. Therefore, we suggest an approach to achieve a geographical subdivision of the Chinese electricity grid, corresponding to the interprovincial regional power grids, namely the North, the Northeast, the East, the Central, the Northwest, and the Southwest China Grids, and the China Southern Power Grid. The approach combines information from the Chinese national plans on for capacity changes in both production and distribution grids, and knowledge of resource availability. The results show that nationally, marginal technology is coal-fired electricity generation, which is the same scenario in the North and Northwest China Grid. In the Northeast, East, and Central China Grid, nuclear power gradually replaces coal-fired electricity and becomes the marginal technology. In the Southwest China Grid and the China Southern Power Grid, the marginal electricity is hydropower towards 2030.

Power generation using sugar cane bagasse: A heat recovery analysis

Science.gov (United States)

Seguro, Jean Vittorio

The sugar industry is facing the need to improve its performance by increasing efficiency and developing profitable by-products. An important possibility is the production of electrical power for sale. Co-generation has been practiced in the sugar industry for a long time in a very inefficient way with the main purpose of getting rid of the bagasse. The goal of this research was to develop a software tool that could be used to improve the way that bagasse is used to generate power. Special focus was given to the heat recovery components of the co-generation plant (economizer, air pre-heater and bagasse dryer) to determine if one, or a combination, of them led to a more efficient co-generation cycle. An extensive review of the state of the art of power generation in the sugar industry was conducted and is summarized in this dissertation. Based on this models were developed. After testing the models and comparing the results with the data collected from the literature, a software application that integrated all these models was developed to simulate the complete co-generation plant. Seven different cycles, three different pressures, and sixty-eight distributions of the flue gas through the heat recovery components can be simulated. The software includes an economic analysis tool that can help the designer determine the economic feasibility of different options. Results from running the simulation are presented that demonstrate its effectiveness in evaluating and comparing the different heat recovery components and power generation cycles. These results indicate that the economizer is the most beneficial option for heat recovery and that the use of waste heat in a bagasse dryer is the least desirable option. Quantitative comparisons of several possible cycle options with the widely-used traditional back-pressure turbine cycle are given. These indicate that a double extraction condensing cycle is best for co-generation purposes. Power generation gains between 40 and

Development of Natural Gas Fired Combined Cycle Plant for Tri-Generation of Power, Cooling and Clean Water Using Waste Heat Recovery: Techno-Economic Analysis

Directory of Open Access Journals (Sweden)

Gowtham Mohan

2014-10-01

Full Text Available Tri-generation is one of the most efficient ways for maximizing the utilization of available energy. Utilization of waste heat (flue gases liberated by the Al-Hamra gas turbine power plant is analyzed in this research work for simultaneous production of: (a electricity by combining steam rankine cycle using heat recovery steam generator (HRSG; (b clean water by air gap membrane distillation (AGMD plant; and (c cooling by single stage vapor absorption chiller (VAC. The flue gases liberated from the gas turbine power cycle is the prime source of energy for the tri-generation system. The heat recovered from condenser of steam cycle and excess heat available at the flue gases are utilized to drive cooling and desalination cycles which are optimized based on the cooling energy demands of the villas. Economic and environmental benefits of the tri-generation system in terms of cost savings and reduction in carbon emissions were analyzed. Energy efficiency of about 82%–85% is achieved by the tri-generation system compared to 50%–52% for combined cycles. Normalized carbon dioxide emission per MW·h is reduced by 51.5% by implementation of waste heat recovery tri-generation system. The tri-generation system has a payback period of 1.38 years with cumulative net present value of $66 million over the project life time.

Estimating the power efficiency of the thermal power plant modernization by using combined-cycle technologies

International Nuclear Information System (INIS)

Hovhannisyan, L.S.; Harutyunyan, N.R.

2013-01-01

The power efficiency of the thermal power plant (TPP) modernization by using combined-cycle technologies is introduced. It is shown that it is possible to achieve the greatest decrease in the specific fuel consumption at modernizing the TPP at the expense of introducing progressive 'know-how' of the electric power generation: for TPP on gas, it is combined-cycle, gas-turbine superstructures of steam-power plants and gas-turbines with heat utilization

Distributed photovoltaic architecture powering a DC bus: Impact of duty cycle and load variations on the efficiency of the generator

Science.gov (United States)

Allouache, Hadj; Zegaoui, Abdallah; Boutoubat, Mohamed; Bokhtache, Aicha Aissa; Kessaissia, Fatma Zohra; Charles, Jean-Pierre; Aillerie, Michel

2018-05-01

This paper focuses on a photovoltaic generator feeding a load via a boost converter in a distributed PV architecture. The principal target is the evaluation of the efficiency of a distributed photovoltaic architecture powering a direct current (DC) PV bus. This task is achieved by outlining an original way for tracking the Maximum Power Point (MPP) taking into account load variations and duty cycle on the electrical quantities of the boost converter and on the PV generator output apparent impedance. Thereafter, in a given sized PV system, we analyze the influence of the load variations on the behavior of the boost converter and we deduce the limits imposed by the load on the DC PV bus. The simultaneous influences of 1- the variation of the duty cycle of the boost converter and 2- the load power on the parameters of the various components of the photovoltaic chain and on the boost performances are clearly presented as deduced by simulation.

Exergy analysis of biomass organic Rankine cycle for power generation

Science.gov (United States)

Nur, T. B.; Sunoto

2018-02-01

The study examines proposed small biomass-fed Organic Rankine Cycle (ORC) power plant through exergy analysis. The system consists of combustion burner unit to utilize biomass as fuel, and organic Rankine cycle unit to produce power from the expander. The heat from combustion burner was transfered by thermal oil heater to evaporate ORC working fluid in the evaporator part. The effects of adding recuperator into exergy destruction were investigated. Furthermore, the results of the variations of system configurations with different operating parameters, such as the evaporating pressures, ambient temperatures, and expander pressures were analyzed. It was found that the largest exergy destruction occurs during processes are at combustion part, followed by evaporator, condenser, expander, and pump. The ORC system equipped with a recuperator unit exhibited good operational characteristics under wide range conditions compared to the one without recuperator.

Fuel-cycle analysis of early market applications of fuel cells: Forklift propulsion systems and distributed power generation

Energy Technology Data Exchange (ETDEWEB)

Elgowainy, Amgad; Gaines, Linda; Wang, Michael [Center for Transportation Research, Argonne National Laboratory, 9700 South Cass Ave, Argonne, IL 60439 (United States)

2009-05-15

Forklift propulsion systems and distributed power generation are identified as potential fuel cell applications for near-term markets. This analysis examines fuel cell forklifts and distributed power generators, and addresses the potential energy and environmental implications of substituting fuel-cell systems for existing technologies based on fossil fuels and grid electricity. Performance data and the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model are used to estimate full fuel-cycle emissions and use of primary energy sources. The greenhouse gas (GHG) impacts of fuel-cell forklifts using hydrogen from steam reforming of natural gas are considerably lower than those using electricity from the average U.S. grid. Fuel cell generators produce lower GHG emissions than those associated with the U.S. grid electricity and alternative distributed combustion technologies. If fuel-cell generation technologies approach or exceed the target efficiency of 40%, they offer significant reduction in energy use and GHG emissions compared to alternative combustion technologies. (author)

Cycling of conventional power plants: Technical limits and actual costs

International Nuclear Information System (INIS)

Van den Bergh, Kenneth; Delarue, Erik

2015-01-01

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

Modeling of Optimal Power Generation using Multiple Kites

NARCIS (Netherlands)

Williams, P.; Lansdorp, B.; Ockels, W.J.

2008-01-01

Kite systems have the potential to revolutionize energy generation. Large scale systems are envisioned that can fly autonomously in “power generation” cycles which drive a ground-based generator. In order for such systems to produce power efficiently, good models of the system are required. This

Life cycle assessment of coal-fired power plants and sensitivity analysis of CO2 emissions from power generation side

Science.gov (United States)

Yin, Libao; Liao, Yanfen; Zhou, Lianjie; Wang, Zhao; Ma, Xiaoqian

2017-05-01

The life cycle assessment and environmental impacts of a 1000MW coal-fired power plant were carried out in this paper. The results showed that the operation energy consumption and pollutant emission of the power plant are the highest in all sub-process, which accounts for 93.93% of the total energy consumption and 92.20% of the total emission. Compared to other pollutant emissions from the coal-fired power plant, CO2 reached up to 99.28%. Therefore, the control of CO2 emission from the coal-fired power plants was very important. Based on the BP neural network, the amount of CO2 emission from the generation side of coal-fired power plants was calculated via carbon balance method. The results showed that unit capacity, coal quality and unit operation load had great influence on the CO2 emission from coal-fired power plants in Guangdong Province. The use of high volatile and high heat value of coal also can reduce the CO2 emissions. What’s more, under higher operation load condition, the CO2 emissions of 1 kWh electric energy was less.

Thermodynamic analysis and comparison between CO_2 transcritical power cycles and R245fa organic Rankine cycles for low grade heat to power energy conversion

International Nuclear Information System (INIS)

Li, L.; Ge, Y.T.; Luo, X.; Tassou, S.A.

2016-01-01

Highlights: • CO_2 is a promising working fluid to be applied in low-grade power generation systems. • Thermodynamic models of CO_2 transcritical power cycles (T-CO_2) and R245fa ORC were developed. • Energy and exergy analyses were carried out for T-CO_2 and R245fa ORC systems. • Optimal system designs are existed for both T-CO_2 and R245fa ORC systems. - Abstract: In this paper, a theoretical study is conducted to investigate and compare the performance of CO_2 transcritical power cycles (T-CO_2) and R245fa organic Rankine cycles (ORCs) using low-grade thermal energy to produce useful shaft or electrical power. Each power cycle consists of typical Rankine cycle components, such as a working fluid pump, gas generator or evaporator, turbine with electricity generator, air cooled condenser and recuperator (internal heat exchanger). The thermodynamic models of both cycles have been developed and are applied to calculate and compare the cycle thermal and exergy efficiencies at different operating conditions and control strategies. The simulation results show that the system performances for both cycles vary with different operating conditions. When the heat source (waste heat) temperature increases from 120 °C to 260 °C and heat sink (cooling air) temperature is reduced from 20 °C to 0 °C, both thermal efficiencies of R245fa ORC and T-CO_2 with recuperator can significantly increase. On the other hand, R245fa ORC and T-CO_2 exergy efficiencies increase with lower heat sink temperatures and generally decrease with higher heat source temperatures. In addition, with the same operating conditions and heat transfer assumptions, the thermal and exergy efficiencies of R245fa ORCs are both slightly higher than those of T-CO_2. However, the efficiencies of both cycles can be enhanced by installing a recuperator in each system at specified operating conditions. Ultimately, optimal operating states can be predicted, with particular focus on the working fluid expander

High-potential Working Fluids for Next Generation Binary Cycle Geothermal Power Plants

Energy Technology Data Exchange (ETDEWEB)

Zia, Jalal [GE Global Research; Sevincer, Edip; Chen, Huijuan; Hardy, Ajilli; Wickersham, Paul; Kalra, Chiranjeev; Laursen, Anna Lis; Vandeputte, Thomas

2013-06-29

A thermo-economic model has been built and validated for prediction of project economics of Enhanced Geothermal Projects. The thermo-economic model calculates and iteratively optimizes the LCOE (levelized cost of electricity) for a prospective EGS (Enhanced Geothermal) site. It takes into account the local subsurface temperature gradient, the cost of drilling and reservoir creation, stimulation and power plant configuration. It calculates and optimizes the power plant configuration vs. well depth. Thus outputs from the model include optimal well depth and power plant configuration for the lowest LCOE. The main focus of this final report was to experimentally validate the thermodynamic properties that formed the basis of the thermo-economic model built in Phase 2, and thus build confidence that the predictions of the model could be used reliably for process downselection and preliminary design at a given set of geothermal (and/or waste heat) boundary conditions. The fluid and cycle downselected was based on a new proprietary fluid from a vendor in a supercritical ORC cycle at a resource condition of 200°C inlet temperature. The team devised and executed a series of experiments to prove the suitability of the new fluid in realistic ORC cycle conditions. Furthermore, the team performed a preliminary design study for a MW-scale turbo expander that would be used for a supercritical ORC cycle with this new fluid. The following summarizes the main findings in the investigative campaign that was undertaken: 1. Chemical compatibility of the new fluid with common seal/gasket/Oring materials was found to be problematic. Neoprene, Viton, and silicone materials were found to be incompatible, suffering chemical decomposition, swelling and/or compression set issues. Of the materials tested, only TEFLON was found to be compatible under actual ORC temperature and pressure conditions. 2. Thermal stability of the new fluid at 200°C and 40 bar was found to be acceptable after 399

A Co-Powered Biomass and Concentrated Solar Power Rankine Cycle Concept for Small Size Combined Heat and Power Generation

Directory of Open Access Journals (Sweden)

Eileen Tortora

2013-03-01

Full Text Available The present work investigates the matching of an advanced small scale Combined Heat and Power (CHP Rankine cycle plant with end-user thermal and electric load. The power plant consists of a concentrated solar power field co-powered by a biomass furnace to produce steam in a Rankine cycle, with a CHP configuration. A hotel was selected as the end user due to its high thermal to electric consumption ratio. The power plant design and its operation were modelled and investigated by adopting transient simulations with an hourly distribution. The study of the load matching of the proposed renewable power technology and the final user has been carried out by comparing two different load tracking scenarios, i.e., the thermal and the electric demands. As a result, the power output follows fairly well the given load curves, supplying, on a selected winter day, about 50 GJ/d of thermal energy and the 6 GJ/d of electric energy, with reduced energy dumps when matching the load.

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

International Nuclear Information System (INIS)

Nishimura, A.; Hayashi, Y.; Tanaka, K.; Hirota, M.; Kato, S.; Ito, M.; Araki, K.; Hu, E.J.

2010-01-01

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 2 year) in Gobi desert. Consequently, it appears that using mc-Si PV in Gobi desert is the best option.

High performance integrated solar combined cycles with minimum modifications to the combined cycle power plant design

International Nuclear Information System (INIS)

Manente, Giovanni

2016-01-01

Highlights: • Off-design model of a 390 MW_e three pressure combined cycle developed and validated. • The off-design model is used to evaluate different hybridization schemes with solar. • Power boosting and fuel saving with different design modifications are considered. • Maximum solar share of total electricity is only 1% with the existing equipment. • The maximum incremental solar radiation-to-electrical efficiency approaches 29%. - Abstract: The integration of solar energy into natural gas combined cycles has been successfully demonstrated in several integrated solar combined cycles since the beginning of this decade in many countries. There are many motivations that drive investments on integrated solar combined cycles which are primarily the repowering of existing power plants, the compliance with more severe environmental laws on emissions and the mitigation of risks associated with large solar projects. Integrated solar combined cycles are usually developed as brownfield facilities by retrofitting existing natural gas combined cycles and keeping the existing equipment to minimize costs. In this work a detailed off-design model of a 390 MW_e three pressure level natural gas combined cycle is built to evaluate different integration schemes of solar energy which either keep the equipment of the combined cycle unchanged or include new equipment (steam turbine, heat recovery steam generator). Both power boosting and fuel saving operation strategies are analyzed in the search for the highest annual efficiency and solar share. Results show that the maximum incremental power output from solar at design solar irradiance is limited to 19 MW_e without modifications to the existing equipment. Higher values are attainable only including a larger steam turbine. High solar radiation-to-electrical efficiencies in the range 24–29% can be achieved in the integrated solar combined cycle depending on solar share and extension of tube banks in the heat recovery

Evaluation of the Life Cycle Greenhouse Gas Emissions from Hydroelectricity Generation Systems

Directory of Open Access Journals (Sweden)

Akhil Kadiyala

2016-06-01

Full Text Available This study evaluated the life cycle greenhouse gas (GHG emissions from different hydroelectricity generation systems by first performing a comprehensive review of the hydroelectricity generation system life cycle assessment (LCA studies and then subsequent computation of statistical metrics to quantify the life cycle GHG emissions (expressed in grams of carbon dioxide equivalent per kilowatt hour, gCO2e/kWh. A categorization index (with unique category codes, formatted as “facility type-electric power generation capacity” was developed and used in this study to evaluate the life cycle GHG emissions from the reviewed hydroelectricity generation systems. The unique category codes were labeled by integrating the names of the two hydro power sub-classifications, i.e., the facility type (impoundment (I, diversion (D, pumped storage (PS, miscellaneous hydropower works (MHPW and the electric power generation capacity (micro (µ, small (S, large (L. The characterized hydroelectricity generation systems were statistically evaluated to determine the reduction in corresponding life cycle GHG emissions. A total of eight unique categorization codes (I-S, I-L, D-µ, D-S, D-L, PS-L, MHPW-µ, MHPW-S were designated to the 19 hydroelectricity generation LCA studies (representing 178 hydropower cases using the proposed categorization index. The mean life cycle GHG emissions resulting from the use of I-S (N = 24, I-L (N = 8, D-µ (N = 3, D-S (N = 133, D-L (N = 3, PS-L (N = 3, MHPW-µ (N = 3, and MHPW-S (N = 1 hydroelectricity generation systems are 21.05 gCO2e/kWh, 40.63 gCO2e/kWh, 47.82 gCO2e/kWh, 27.18 gCO2e/kWh, 3.45 gCO2e/kWh, 256.63 gCO2e/kWh, 19.73 gCO2e/kWh, and 2.78 gCO2e/kWh, respectively. D-L hydroelectricity generation systems produced the minimum life cycle GHGs (considering the hydroelectricity generation system categories with a representation of at least two cases.

Strengthening power generation efficiency utilizing liquefied natural gas cold energy by a novel two-stage condensation Rankine cycle (TCRC) system

International Nuclear Information System (INIS)

Bao, Junjiang; Lin, Yan; Zhang, Ruixiang; Zhang, Ning; He, Gaohong

2017-01-01

Highlights: • A two-stage condensation Rankine cycle (TCRC) system is proposed. • Net power output and thermal efficiency increases by 45.27% and 42.91%. • The effects of the condensation temperatures are analyzed. • 14 working fluids (such as propane, butane etc.) are compared. - Abstract: For the low efficiency of the traditional power generation system with liquefied natural gas (LNG) cold energy utilization, by improving the heat transfer characteristic between the working fluid and LNG, this paper has proposed a two-stage condensation Rankine cycle (TCRC) system. Using propane as working fluid, compared with the combined cycle in the conventional LNG cold energy power generation method, the net power output, thermal efficiency and exergy efficiency of the TCRC system are respectively increased by 45.27%, 42.91% and 52.31%. Meanwhile, the effects of the first-stage and second-stage condensation temperature and LNG vaporization pressure on the performance and cost index of the TCRC system (net power output, thermal efficiency, exergy efficiency and UA) are analyzed. Finally, using the net power output as the objective function, with 14 organic fluids (such as propane, butane etc.) as working fluids, the first-stage and second-stage condensation temperature at different LNG vaporization pressures are optimized. The results show that there exists a first-stage and second-stage condensation temperature making the performance of the TCRC system optimal. When LNG vaporization pressure is supercritical pressure, R116 has the best economy among all the investigated working fluids, and while R150 and R23 are better when the vaporization pressure of LNG is subcritical.

INTEGRATED PYROLYSIS COMBINED CYCLE BIOMASS POWER SYSTEM CONCEPT DEFINITION

International Nuclear Information System (INIS)

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

2003-01-01

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 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

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.

Thermo-Economic Evaluation of Organic Rankine Cycles for Geothermal Power Generation Using Zeotropic Mixtures

Directory of Open Access Journals (Sweden)

Florian Heberle

2015-03-01

Full Text Available We present a thermo-economic evaluation of binary power plants based on the Organic Rankine Cycle (ORC for geothermal power generation. The focus of this study is to analyse if an efficiency increase by using zeotropic mixtures as working fluid overcompensates additional requirements regarding the major power plant components. The optimization approach is compared to systems with pure media. Based on process simulations, heat exchange equipment is designed and cost estimations are performed. For heat source temperatures between 100 and 180 °C selected zeotropic mixtures lead to an increase in second law efficiency of up to 20.6% compared to pure fluids. Especially for temperatures about 160 °C, mixtures like propane/isobutane, isobutane/isopentane, or R227ea/R245fa show lower electricity generation costs compared to the most efficient pure fluid. In case of a geothermal fluid temperature of 120 °C, R227ea and propane/isobutane are cost-efficient working fluids. The uncertainties regarding fluid properties of zeotropic mixtures, mainly affect the heat exchange surface. However, the influence on the determined economic parameter is marginal. In general, zeotropic mixtures are a promising approach to improve the economics of geothermal ORC systems. Additionally, the use of mixtures increases the spectrum of potential working fluids, which is important in context of present and future legal requirements considering fluorinated refrigerants.

Output power analyses for the thermodynamic cycles of thermal power plants

International Nuclear Information System (INIS)

Sun Chen; Cheng Xue-Tao; Liang Xin-Gang

2014-01-01

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)

Investigations on the application of zeotropic fluid mixtures in the organic rankine cycle for the geothermal power generation; Untersuchung zum Einsatz von zeotropen Fluidgemischen im Organic Rankine Cycle fuer die geothermische Stromerzeugung

Energy Technology Data Exchange (ETDEWEB)

Heberle, Florian

2013-04-01

The organic rankine cycle is a thermodynamic cycle process which uses an organic fluid working fluid instead of water in comparison to the commercial rankine process. The organic rankine cycle facilitates sufficiently high pressures at moderate temperatures. The organic rankine cycle significantly expands the technically possible and economically feasible ranges of application of such heat and power processes. The geothermal power is a very attractive field of application. Thermal water with a temperature of nearly 100 Celsius can be used for the power generation by means of the organic rankine cycle. Especially zeotropic mixtures are interesting as a working fluid. This is due to a non-isothermal phase change to a temperature glide which adapts very well to the temperature progress of the heat source. The author of the book under consideration reports on the application of different mixtures in the organic rankine cycle. The evaluation is based on a thermodynamic analysis and considers also toxicological, ecologic, technical as well as economic aspects.

Performance analysis of an integrated gas-, steam- and organic fluid-cycle thermal power plant

International Nuclear Information System (INIS)

Oko, C.O.C.; Njoku, I.H.

2017-01-01

This paper presents the performance analysis of an existing combined cycle power plant augmented with a waste heat fired organic Rankine cycle power plant for extra power generation. This was achieved by performing energy and exergy analysis of the integrated gas-, steam- and organic fluid-cycle thermal power plant (IPP). Heat source for the subcritical organic Rankine cycle (ORC) was the exhaust flue gases from the heat recovery steam generators of a 650 MW natural gas fired combined cycle power plant. The results showed that extra 12.4 MW of electricity was generated from the attached ORC unit using HFE7100 as working fluid. To select ORC working fluid, ten isentropic fluids were screened and HFE7100 produced the highest net power output and cycle efficiency. Exergy and energy efficiencies of the IPP improved by 1.95% and 1.93%, respectively. The rate of exergy destruction in the existing combined cycle plant was highest in the combustion chamber, 59%, whereas in the ORC, the highest rate of exergy destruction occurred in the evaporator, 62%. Simulations showed exergy efficiency of the IPP decreased with increasing ambient temperature. Exit stack flue gas temperature reduced from 126 °C in the combined cycle power plant to 100 °C in the integrated power plant. - Highlights: • Combined cycle plant retrofitted with ORC produced extra 12.4 MW electric power. • ORC is powered with low temperature flue gas from an existing combined cycle plant. • Exergy destruction rate in integrated plant(IPP) is less than in combined plant. • Exit stack temperature of the IPP has less environmental thermal pollution. • Exergy and energy efficiencies of the IPP improved by 1.95% and 1.93%, respectively.

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

Science.gov (United States)

Liu, Huacai; Yin, Xiuli; Wu, Chuangzhi

2014-01-01

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. PMID:25383383

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.

Optimization of disk generator performance for base-load power plant systems applications

International Nuclear Information System (INIS)

Teare, J.D.; Loubsky, W.J.; Lytle, J.K.; Louis, J.F.

1980-01-01

Disk generators for use in base-load MHD power plants are examined for both open-cycle and closed-cycle operating modes. The OCD cases are compared with PSPEC results for a linear channel; enthalpy extractions up to 23% with 71% isentropic efficiency are achievable with generator inlet conditions similar to those used in PSPEC, thus confirming that the disk configuration is a viable alternative for base-load power generation. The evaluation of closed-cycle disks includes use of a simplified cycle model. High system efficiencies over a wide range of power levels are obtained for effective Hall coefficients in the range 2.3 to 4.9. Cases with higher turbulence (implying β/sub eff/ less than or equal to 2.4) yield high system efficiencies at power levels of 100 to 500 MW/sub e/. All these CCD cases compare favorably with linear channels reported in the GE ECAS study, yielding higher isentropic efficiences for a given enthalpy extraction. Power densities in the range 70 to 170 MW/m 3 appear feasible, leading to very compact generator configurations

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.

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 t echnoeconomic 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.

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

demand. The environmental impacts related to potential future energy systems in Ireland for 2025 with high shares of wind power were evaluated using life cycle assessment (LCA), focusing on cycling emissions (due to part-load operation and start-ups) from dispatchable generators. Part-load operations...... significantly affect the average power plant efficiency, with all units seeing an average yearly efficiency noticeably less than optimal. In particular, load following units, on average, saw an 11% reduction. Given that production technologies are typically modeled assuming steady-state operation at full load...

Technical and economic assessment of power generation from municipal solid waste incineration on steam cycle

Energy Technology Data Exchange (ETDEWEB)

Romero Luna, Carlos Manuel; Carrocci, Luiz Roberto; Ferrufino, Gretta Larisa Aurora Arce; Balestieri, Jose Antonio Perrella [Dept. of Energy. UNESP, Sao Paulo State University, Guaratingueta, SP (Brazil)], e-mails: carrocci@feg.unesp.br, perrella@feg.unesp.br

2010-07-01

Nowadays, there is a concern in development of environmentally friendly methods for a municipal solid waste (MSW) management and demand for renewable energy sources. The source of waste is increasing, and the capacity and availability Landfill treatment and disposal are coming to be insufficient. In Sao Paulo City, the 10 million inhabitants produce 10,000 t of residential solid waste daily, being that 76% this quantity goes to landfill sites. In order to adopt a new treatment technology for MSW that will promote a solution minimizing this problem, within the order of priorities regarding waste management, the MSW incineration with energy recovery shown as the leading choice on the point of view of efficiency in converting energy. MSW incineration with energy recovery received wide acceptance from various countries including European Union members and the rest of the world in the past 15 years. Incineration has the ability decrease 90 % the volume of waste to be used in landfills, increasing the useful life of existing as well as a reduction in the emission of greenhouse gases. MSW incineration systems have a low global warming potential (GWP). now has become a less important source of dioxins and furans due to the current available technology. MSW incineration with energy recovery could contribute considerably in the energy matrix, thus promote the conservation of non-renewable resources. This paper proposes the assessment the technical and economic feasibility of a steam cycle with conventional steam generator for MSW incineration with energy recovery for power generation in Sao Paulo City. Will be developed a thermoeconomic analysis aiming at the total power generation product of MSW incineration, and the assessment investment cost regarding the total sale of power generated. The study shows that Sao Paulo City has potential for power generation from the MSW incineration, although it has a high cost investment this technology shown as a suitable alternative for

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.

Comparison of the dielectric electroactive polymer generator energy harvesting cycles

DEFF Research Database (Denmark)

Dimopoulos, Emmanouil; Trintis, Ionut; Munk-Nielsen, Stig

2013-01-01

The Dielectric ElectroActive Polymer (DEAP) generator energy harvesting cycles have been in the spotlight of the scientific interest for the past few years. Indeed, several articles have demonstrated thorough and comprehensive comparisons of the generator fundamental energy harvesting cycles......, namely Constant Charge (CC), Constant Voltage (CV) and Constant E-field (CE), based on averaged theoretical models. Yet, it has not been possible until present to validate the outcome of those comparisons via respective experimental results. In this paper, all three primary energy harvesting cycles...... are experimentally compared, based upon the coupling of a DEAP generator with a bidirectional non-isolated power electronic converter, by means of energy gain, energy harvesting efficiency and energy conversion efficiency....

Power generation from solid fuels

CERN Document Server

Spliethoff, Hartmut

2010-01-01

Power Generation from Solid Fuels introduces the different technologies to produce heat and power from solid fossil (hard coal, brown coal) and renewable (biomass, waste) fuels, such as combustion and gasification, steam power plants and combined cycles etc. The book discusses technologies with regard to their efficiency, emissions, operational behavior, residues and costs. Besides proven state of the art processes, the focus is on the potential of new technologies currently under development or demonstration. The main motivation of the book is to explain the technical possibilities for reduci

Reduction of impurity contamination in a working gas for closed-cycle MHD power generation

International Nuclear Information System (INIS)

Endo, N.; Yoshikawa, K.; Shioda, S.

1989-01-01

The reduction of impurity contamination in a working inert gas for closed-cycle MHD power generation is examined. A conceptual operation system of regenerative heat exchangers is proposed for minimizing the amount of combustion gas which mixes in the working inert gas. Experiments have shown that this mixing can be reduced significantly by evacuating and flushing the heat exchangers after being heated by combustion gas. Calculations have shown that, among the main molecular contaminants in the working inert gas, CO 2 , H 2 O and O 2 can be removed as compounds with the seed material, while N 2 and H 2 can be reduced by a partial purification of the circulating working inert gas. (author)

Comparative Life-Cycle Cost Analysis Of Solar Photovoltaic Power ...

African Journals Online (AJOL)

Comparative Life-Cycle Cost Analysis Of Solar Photovoltaic Power System And Diesel Generator System For Remote Residential Application In Nigeria. ... like capital cost, and diesel fuel costs are varied. The results show the photovoltaic system to be more cost-effective at low-power ranges of electrical energy supply.

Is there a tomorrow for nuclear power generation?

International Nuclear Information System (INIS)

Kanoh, T.

1996-01-01

Critical comments are publicly made about nuclear power generation and the nuclear fuel cycle. This criticism is directed at three areas of concern: accidents, radioactive waste disposal, and proliferation of nuclear weapons. In addition, there are other comments that ask 'Why are there countries pushing for nuclear power generation when other countries around the world are giving it up?' and 'Will further efforts to develop new energy sources and energy conservation not eliminate the nneed for nuclear power generation?' Such critical comments appear in some media more often than those expressing other opinions. Is there really no tomorrow for nuclear power? This question is studied below. (author)

An Exploratory Study of Thermoelectrostatic Power Generation for Space Flight Applications

Science.gov (United States)

Beam, Benjamin H.

1960-01-01

A study has been made of a process in which a solar heating cycle is combined with an electrostatic cycle for generating electrical power for space vehicle applications. The power unit, referred to as a thermoelectrostatic generator, is a thin film, solid dielectric capacitor alternately heated by solar radiation and cooled by radiant emission. The theory of operation to extract electrical power is presented. Results of an experiment to illustrate the principle are described. Estimates of the performance of this type of device in space in the vicinity of earth are included. Values of specific power of several kilowatts per kilogram of generator weight are calculated for such a device employing polyethylene terephthalate dielectric.

Impacts on human health from the coal and nuclear fuel cycles and other technologies associated with electric power generation and transmission

International Nuclear Information System (INIS)

Radford, E.P.

1980-01-01

Major public health impacts of electric power generation and transmission associated with the nuclear fuel cycle and with coal use are evaluated. Only existing technology is evaluated. The only health effects of concern are those leading to definable human disease and injury. Health effects are scaled to a nominal 1000 Megawatt (electric) plant fueled by either option. Comparison of the total health effects to the general public gives: nuclear, 0.03 to 0.05 major health effects per 1000 MWe per year; coal, 0.7 to 3.7 per 1000 MWe per year. Thus for the general public the health risks from the coal cycle are about 50 times greater than for the nuclear cycle. Health effects to workers in the industry are currently quite high. For the nuclear cycle, 4.6 to 5.1 major health impacts per 1000 MWe per year; for coal, 6.5 to 10.9. The two-fold greater risk for the coal cycle is primarily due to high injury rates in coal miners. There is no evidence that electrical transmission contributes any health effects to the general public, except for episodes where broken power lines come in contact with people. For power line workers, the risk is estimated at 0.1 serious injury per 1000 MWe per year

Impacts on human health from the coal and nuclear fuel cycles and other technologies associated with electric power generation and transmission

International Nuclear Information System (INIS)

Radford, E.P.

1980-07-01

The report evaluates major public health impacts of electric power generation and transmission associated with the nuclear fuel cycle and with coal use. Only existing technology is evaluated. For the nuclear cycle, effects of future use of fuel reprocessing and long-term radioactive waste disposal are briefly considered. The health effects of concern are those leading to definable human disease and injury. Health effects are scaled to numbers of persons and activities associated with a nominal 1000-megawatt electric plant fueled by either option. Comparison of the total health effects to the general public shows that the health risks from the coal cycle are about 50 times greater than for the nuclear cycle (coal, 0.7-3.7 major health effects per 1000 MWe per year; nuclear, 0.03-0.05 per 1000 MWe per year). For workers, these rates are higher. No evidence is found that electrical transmission contributes any health effects to the general public, except when broken power lines come in contact with people

Thermodynamic and economic analysis and optimization of power cycles for a medium temperature geothermal resource

International Nuclear Information System (INIS)

Coskun, Ahmet; Bolatturk, Ali; Kanoglu, Mehmet

2014-01-01

Highlights: • We conduct the thermodynamic and economic analysis of various geothermal power cycles. • The optimization process was performed to minimize the exergy losses. • Kalina cycle is a new technology compared to flash and binary cycles. • It is shown that Kalina cycle presents a viable choice for both thermodynamically and economically. - Abstract: Geothermal power generation technologies are well established and there are numerous power plants operating worldwide. Turkey is rich in geothermal resources while most resources are not exploited for power production. In this study, we consider geothermal resources in Kutahya–Simav region having geothermal water at a temperature suitable for power generation. The study is aimed to yield the method of the most effective use of the geothermal resource and a rational thermodynamic and economic comparison of various cycles for a given resource. The cycles considered include double-flash, binary, combined flash/binary, and Kalina cycle. The selected cycles are optimized for the turbine inlet pressure that would generate maximum power output and energy and exergy efficiencies. The distribution of exergy in plant components and processes are shown using tables. Maximum first law efficiencies vary between 6.9% and 10.6% while the second law efficiencies vary between 38.5% and 59.3% depending on the cycle considered. The maximum power output, the first law, and the second law efficiencies are obtained for Kalina cycle followed by combined cycle and binary cycle. An economic analysis of four cycles considered indicates that the cost of producing a unit amount of electricity is 0.0116 $/kW h for double flash and Kalina cycles, 0.0165 $/kW h for combined cycle and 0.0202 $/kW h for binary cycle. Consequently, the payback period is 5.8 years for double flash and Kalina cycles while it is 8.3 years for combined cycle and 9 years for binary cycle

Dual-pressure vaporization Kalina cycle for cascade reclaiming heat resource for power generation

International Nuclear Information System (INIS)

Guo, Zhanwei; Zhang, Zhi; Chen, Yaping; Wu, Jiafeng; Dong, Cong

2015-01-01

Graphical abstract: Schematic of the dual-pressure evaporation Kalina cycle. - Highlights: • Dual-pressure vaporization Kalina cycle for high-grade heat resource is investigated. • It is designed with 2nd evaporation branch for cascade utilization of heat resource. • Work and basic concentrations, dew point temperature of evaporation are optimized. • Power recovery efficiency of proposed cycle is 17% higher than that of Kalina cycle. • Dual-p vaporization Kalina cycle fits reclaiming heat resource higher than 350 °C. - Abstract: To further improve the cycle efficiency with the heat transfer curves between higher than 350 °C heat resource and the evaporating working medium of the Kalina cycle and to reduce the exhaust temperature of heat resource, the dual-pressure vaporization Kalina cycle for cascade utilization of high-to-mid grade heat resource is proposed. The optimization was conducted for parameters in this modified Kalina cycle such as concentrations of work solution and basic solution, evaporation dew point temperature. Under the conditions of inlet temperatures of heat resource and cooling water of respectively 400 °C and 25 °C and the constraints of proper heat transfer pinch point temperature differences, the maximum evaporation pressure not exceeds 20 MPa, the vapour quality at the turbine outlet is greater than 0.85 and the exhaust temperature of heat resource is not lower than 90 °C, the optimum parameters are obtained that the work and basic concentrations are 0.45 and 0.272 respectively, the dew point temperature of evaporation is 300 °C, and the corresponding power recovery efficiency of the dual-pressure vaporization Kalina cycle reaches 27%, which is 17% higher than that of the Kalina cycle with optimum parameters.

Energy Conversion Advanced Heat Transport Loop and Power Cycle

Energy Technology Data Exchange (ETDEWEB)

Oh, C. H.

2006-08-01

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 3 turbines and 4 compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with 3 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 an 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 various

Life cycle water use for electricity generation: a review and harmonization of literature estimates

International Nuclear Information System (INIS)

Meldrum, J; Nettles-Anderson, S; Heath, G; Macknick, J

2013-01-01

This article provides consolidated estimates of water withdrawal and water consumption for the full life cycle of selected electricity generating technologies, which includes component manufacturing, fuel acquisition, processing, and transport, and power plant operation and decommissioning. Estimates were gathered through a broad search of publicly available sources, screened for quality and relevance, and harmonized for methodological differences. Published estimates vary substantially, due in part to differences in production pathways, in defined boundaries, and in performance parameters. Despite limitations to available data, we find that: water used for cooling of thermoelectric power plants dominates the life cycle water use in most cases; the coal, natural gas, and nuclear fuel cycles require substantial water per megawatt-hour in most cases; and, a substantial proportion of life cycle water use per megawatt-hour is required for the manufacturing and construction of concentrating solar, geothermal, photovoltaic, and wind power facilities. On the basis of the best available evidence for the evaluated technologies, total life cycle water use appears lowest for electricity generated by photovoltaics and wind, and highest for thermoelectric generation technologies. This report provides the foundation for conducting water use impact assessments of the power sector while also identifying gaps in data that could guide future research. (letter)

Report of fiscal 1999 basic survey for promoting joint implementation, etc. Combined cycle power generation project for Surgut No.1 power station in the Russian Federation

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

This paper explains fiscal 1999 survey on a combined cycle power generation project for Surgut power plant in the Russian Federation for the purpose of making the project tied to the COP3 joint implementation. This power plant consists of 16 units with the total capacity of 3,300 MW. This project is to replace the existing superannuated No.1 through No.6 units with a new high-efficiency gas combined cycle power plant. The project plant is planned to comprise of three units, having the capacity of 417 MW, each consisting of one gas turbine and one steam turbine. The average generation efficiency will be improved tremendously from the present 37.2% to 55.2%. The initial investment will be 615 million in US dollars (at 109.2 yen/dollar). Energy saving will be 634,800 toe/year, with cost to effect 9,452 toe-y/million yen. Greenhouse effect gas reduction will be 1,509,000 t-CO2/year, with cost to effect 22.5 t-CO2-y/million yen. The investment recovery period is estimated to be 24 years. The Russian side strongly wishes to be granted a finance on a favorable terms and conditions to realize this project. It is possible that the Russian government requests Japan for grant of the Yen credit. Accordingly, an early start is necessary in order to deal with such request. (NEDO)

Study on the supercritical CO2 power cycles for landfill gas firing gas turbine bottoming cycle

International Nuclear Information System (INIS)

Kim, Min Seok; Ahn, Yoonhan; Kim, Beomjoo; Lee, Jeong Ik

2016-01-01

In this paper, a comparison of nine supercritical carbon dioxide (S-CO 2 ) bottoming power cycles in conjunction with a topping cycle of landfill gas (LFG) fired 5MWe gas turbine is presented. For the comparison purpose, a sensitivity study of the cycle design parameters for nine different cycles was conducted and each cycle thermodynamic performance is evaluated. In addition, the cycle performance evaluation dependency on the compressor inlet temperature variation is performed to investigate how S-CO 2 cycles sensitive to the heat sink temperature variation. Furthermore, the development of new S-CO 2 cycle layouts is reported and the suggested cycles' performances are compared to the existing cycle layouts. It was found that a recompression cycle is not suitable for the bottoming cycle application, but a partial heating cycle has relatively higher net produced work with a simple layout and small number of components. Although a dual heated and flow split cycle has the highest net produced work, it has disadvantages of having numerous components and complex process which requires more sophisticated operational strategies. This study identified that the recuperation process is much more important than the intercooling process to the S-CO 2 cycle design for increasing the thermal efficiency and the net produced work point of view. - Highlights: • Study of nine S-CO 2 power cycle layouts for a small scale landfill gas power generation application. • Development of new S-CO 2 cycle layouts. • Sensitivity analysis of S-CO 2 cycles to evaluate and compare nine cycles' performances.

Summary of nuclear power and fuel cycle data in OECD Member countries

International Nuclear Information System (INIS)

1983-03-01

A questionnaire on Electricity Generation, Nuclear Power and Fuel Cycle Data is distributed annually to OECD Member countries. Member countries were asked to provide, where available, various statistics for the previous calendar year (1982) and modified projections up to the year 2000. Tables 1 to 8 are based on the responses received and update the March 1982 issue. Tables 3 to 8 show the revised electricity, nuclear power and fuel cycle supply and demand projections in OECD Member countries to the year 2000. Figure 1 illustrates the contribution of the different fuel sources to the OECD's electricity generation from 1974 to 1982. Figure 2 shows the nuclear share of electricity generation in the OECD countries for 1982 and 1985. Figure 3 gives the fuel cycle supply and demand from the Tables 5, 6 and 8 in the OECD area

Nuclear steam power plant cycle performance calculations supported by power plant monitoring and results computer

International Nuclear Information System (INIS)

Bettes, R.S.

1984-01-01

The paper discusses the real time performance calculations for the turbine cycle and reactor and steam generators of a nuclear power plant. Program accepts plant measurements and calculates performance and efficiency of each part of the cycle: reactor and steam generators, turbines, feedwater heaters, condenser, circulating water system, feed pump turbines, cooling towers. Presently, the calculations involve: 500 inputs, 2400 separate calculations, 500 steam properties subroutine calls, 200 support function accesses, 1500 output valves. The program operates in a real time system at regular intervals

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)

Macroeconomic effects and benefits of different power generation technologies

International Nuclear Information System (INIS)

Maeenpaeae, I.; Tervo, H.

1994-01-01

The report compares the overall economic effects and benefits of different power station technologies using the FMS long-term simulation model for the Finnish economy. Special emphasis is placed on domestic fuels and new technologies that are on the average of commercialization. The overall economic benefits are compared as such and also assuming the implementation of targets for reductions in carbon dioxide emissions. Without environmental targets nuclear power, natural gas combined cycle and coal gasification combined cycle were shown to be macroeconomically the most profitable means of generating electricity. For the municipal cogeneration of heat and power, a natural gas diesel plant was the most advantageous, followed by solid fuel gasification combined cycle plants. Upon implementation of CO 2 -emission reduction targets nuclear power would remain the most beneficial alternative, but the benefits of wood and wind power rises would be nearly as great. For municipal cogeneration, the wood gasification combined cycle type power plant surpasses gas diesel and the relative benefits of the fluidized bed combustion of wood also increases. (7 refs., 9 tabs.)

Engineering design and exergy analyses for combustion gas turbine based power generation system

International Nuclear Information System (INIS)

Sue, D.-C.; Chuang, C.-C.

2004-01-01

This paper presents the engineering design and theoretical exergetic analyses of the plant for combustion gas turbine based power generation systems. Exergy analysis is performed based on the first and second laws of thermodynamics for power generation systems. The results show the exergy analyses for a steam cycle system predict the plant efficiency more precisely. The plant efficiency for partial load operation is lower than full load operation. Increasing the pinch points will decrease the combined cycle plant efficiency. The engineering design is based on inlet air-cooling and natural gas preheating for increasing the net power output and efficiency. To evaluate the energy utilization, one combined cycle unit and one cogeneration system, consisting of gas turbine generators, heat recovery steam generators, one steam turbine generator with steam extracted for process have been analyzed. The analytical results are used for engineering design and component selection

The reliability of integrated gasification combined cycle (IGCC) power generation units

Energy Technology Data Exchange (ETDEWEB)

Higman, C.; DellaVilla, S.; Steele, B. [Syngas Consultants Ltd. (United Kingdom)

2006-07-01

This paper presents two interlinked projects aimed at supporting the improvement of integrated gasification combined cycle (IGCC) reliability. The one project comprises the extension of SPS's existing ORAP (Operational Reliability Analysis Program) reliability, availability and maintainability (RAM) tracking technology from its existing base in natural gas open and combined cycle operations into IGCC. The other project is using the extended ORAP database to evaluate performance data from existing plants. The initial work has concentrated on evaluating public domain data on the performance of gasification based power and chemical plants. This is being followed up by plant interviews in some 20 plants to verify and expand the database on current performance. 23 refs., 8 figs., 2 tabs.

Project subsidized by the Sunshine Project in fiscal 1982. Report on achievements in the project commissioned from NEDO - development of a hot water utilizing power generation plant and development of a binary cycle power generation plant (Researches on corrosion preventive measures and the cycle optimum for the plant); 1982 nendo nessui riyo hatsuden plant no kaihatsu seika hokokusho. Binary cycle hatsuden plant no kaihatsu (fushoku taisaku no kenkyu oyobi plant saiteki cycle no kenkyu)

Energy Technology Data Exchange (ETDEWEB)

NONE

1983-03-01

As the element research on a 10-MW class geothermal binary cycle power plant to be built in the coming term, researches were made on corrosion preventive measures and the cycle optimum for the plant. This paper reports the achievements in fiscal 1982. In the research on corrosion preventive measures, different kinds of materials were buried in three locations having different soil natures to study corrosion due to soil. The corrosion rate of heat conducting pipes using the heat media R114 was estimated as very small as 1/40 of the corrosion rate in geothermal waters. In the research on the cycle optimum for the plant, experimental research was performed on thermo-dynamic properties and thermal stability of the mixed media using R114 as the main component. As a result, the R114/R112 system was found to have higher pressure than R114, but the media circulation amount is less, and the output at the power transmission terminal increased by 5 to 10%. The system showed the most excellent heat cycle characteristics. In the research of building a power plant installed with two different power generation systems, a computer program was prepared that calculates heat balances all at once for the case of installing a geothermal binary cycle power plant in a geothermal steam power plant. (NEDO)

Carbon dioxide based power generation in renewable energy systems

International Nuclear Information System (INIS)

Kumar, Pramod; Srinivasan, Kandadai

2016-01-01

After a substantial impact on refrigeration, carbon dioxide (CO_2) is gaining considerable attention as a working fluid for thermal power generation. This can be attributed mainly to its excellent heat transfer properties and compactness of components arising from its high density. It has the merit of being amenable to operation in sub-, trans- or super-critical Brayton cycle modes. However, inhibiting factors are high pressures needed when operated in trans- or supercritical cycles and the work of compression eroding most of the work of expansion in sub-critical cycle operation. Some of the lacunae of CO_2 such as high work of compression can be alleviated by using non-mechanical means such as thermal compression using the adsorption technique either for partial compression in high pressure Brayton cycles or for total compression in low pressure cycles. CO_2 has also been proposed as an additive to flammable hydrocarbons such that their flammability can be suppressed and yet retaining their other desirable thermodynamic qualities. This review explores the potential and limitations of thermodynamic cycles where either CO_2 is used alone or as a component in mixture of working fluids. Inter alia, it also highlights the issues of regulation of load management using the efficiency-specific power output plane. When used as a blending component, pinch point in the regenerators affects the cycle performance. The objective is to identify research and developmental challenges involving CO_2 as a working fluid specifically for solar power generation.

Simulation and parametric optimisation of thermal power plant cycles

Directory of Open Access Journals (Sweden)

P. Ravindra Kumar

2016-09-01

Full Text Available The objective of the paper is to analyse parametric studies and optimum steam extraction pressures of three different (subcritical, supercritical and ultra-supercritical coal fired power plant cycles at a particular main steam temperature of 600 °C by keeping the reheat temperature at 537 °C and condenser pressure at 0.09 bar as constant. In order to maximize the heat rate gain possible with supercritical and ultra-supercritical steam conditions, eight stages of feed water heater arrangement with single reheater is considered. The system is optimized in such a way that the percentage exergetic losses are reduced for the increase of the exergetic efficiency and higher fuel utilization. The plant cycles are simulated and optimized by using Cycle Tempo 5.0 simulation software tool. From the simulation study, it is observed that the thermal efficiency of the three different power plant cycles obtained as 41.40, 42.48 and 43.03%, respectively. The specific coal consumption for three different power plant cycles are 0.56, 0.55 and 0.54 Tonnes/MWh. The improvement in feed water temperatures at the inlet of steam generator of respective cycles are 291, 305 and 316 °C.

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.

Theoretical and Experimental Investigation of Liquid Metal MHD Power Generation

Energy Technology Data Exchange (ETDEWEB)

Elliott, D. G.; Cerini, D. J.; Hays, L. G.; Weinberg, E. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA (United States)

1966-11-15

Liquid metal magnetohydrodynamic power generation for space is studied. Closed- loop circulation of liquid metal without moving mechanical parts, and generation of electric power from the circulating metal, have been investigated analytically and experimentally, and the attainable cycle efficiencies have been calculated. Recent literature has pointed out the possibility of efficient a.c. generators with liquid metal as the working fluid, and this type of generator is under study. Analysis indicates that efficiencies up to 65% are attainable in a travelling-wave induction generator at the available liquid metal velocities of 100-200 m/sec, provided the generator has a length/gap ratio of no more than 50 for low friction loss, has an electrical length of no more than three wavelengths for low winding loss, and has end-effect compensation for cancelling finite-length effects in the power-generating region. The analysis leading to these conclusions is presented. The type of end-effect correction being studied is the ''compensating-pole'' technique in which an oscillating magnetic field is applied to the fluid entering and leaving the generator to make the flux linkages within the generator the same as those in a rotating or ''infinite'' generator. An experimental one-wavelength generator employing compensating poles has been fabricated, and empty-channel magnetic field measurements have been completed in preparation for tests with NaK. Two types of field measurements were made: d.c. measurements to determine the field profile as a function of phase angle and a.c. measurements to investigate the synchronization of the compensating poles with the travelling wave. The d.c. results showed that the flux linkages in the power generating region can be held close to those in a rotating machine, and the a.c. results showed that the compensating poles can be accurately synchronized with the travelling wave through transformer coupling. The component efficiencies from the

Nuclear power and the nuclear fuel cycle

International Nuclear Information System (INIS)

Hardy, C.J.; Silver, J.M.

1985-09-01

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

Single generation cycles and delayed feedback cycles are not separate phenomena.

Science.gov (United States)

Pfaff, T; Brechtel, A; Drossel, B; Guill, C

2014-12-01

We study a simple model for generation cycles, which are oscillations with a period of one or a few generation times of the species. The model is formulated in terms of a single delay-differential equation for the population density of an adult stage, with recruitment to the adult stage depending on the intensity of competition during the juvenile phase. This model is a simplified version of a group of models proposed by Gurney and Nisbet, who were the first to distinguish between single-generation cycles and delayed-feedback cycles. According to these authors, the two oscillation types are caused by different mechanisms and have periods in different intervals, which are one to two generation times for single-generation cycles and two to four generation times for delayed-feedback cycles. By abolishing the strict coupling between the maturation time and the time delay between competition and its effect on the population dynamics, we find that single-generation cycles and delayed-feedback cycles occur in the same model version, with a gradual transition between the two as the model parameters are varied over a sufficiently large range. Furthermore, cycle periods are not bounded to lie within single octaves. This implies that a clear distinction between different types of generation cycles is not possible. Cycles of all periods and even chaos can be generated by varying the parameters that determine the time during which individuals from different cohorts compete with each other. This suggests that life-cycle features in the juvenile stage and during the transition to the adult stage are important determinants of the dynamics of density limited populations. Copyright © 2014 Elsevier Inc. All rights reserved.

How is Electricity Generated from Nuclear Power Plant

International Nuclear Information System (INIS)

Lajnef, D.

2015-01-01

Nuclear power is a proven, safe and clean source of power generation. A nuclear power plant is a thermal power station in which the heat source is a nuclear reactor. As is typical in all conventional thermal power stations the heat is used to generate steam which drives a steam turbine: the energy released from continuous fission of the atoms of the fuel is harnessed as heat in either a gas or water, and is used to produce steam. Nuclear Reactors are classified by several methods. It can be classified by type of nuclear reaction, by the moderator material, by coolant or by generation. There are several components common to most types of reactors: fuel, moderator, control rods, coolant, and containment. Nuclear reactor technology has been under continuous development since the first commercial exploitation of civil nuclear power in the 1950s. We can mention seven key reactor attributes that illuminate the essential differences between the various generations of reactors: cost effectiveness, safety, security and non-proliferation, fuel cycle, grid appropriateness and Economics. Today there are about 437 nuclear power reactors that are used to generate electricity in about 30 countries around the world. (author)

North Anna Power Station - Unit 1: Overview of steam generator replacement project activities

International Nuclear Information System (INIS)

Gettler, M.W.; Bayer, R.K.; Lippard, D.W.

1993-01-01

The original steam generators at Virginia Electric and Power Company's (Virginia Power) North Anna Power Station (NAPS) Unit 1 have experienced corrosion-related degradation that require periodic inspection and plugging of steam generator tubes to ensure their continued safe and reliable operation. Despite improvements in secondary water chemistry, continued tube degradation in the steam generators necessitated the removal from service of approximately 20.3 percent of the tubes by plugging, (18.6, 17.3, and 25.1 for steam generators A, B, and C, respectively). Additionally, the unit power was limited to 95 % during, its last cycle of operation. Projections of industry and Virginia Power experience indicated the possibility of mid-cycle inspections and reductions in unit power. Therefore, economic considerations led to the decision to repair the steam generators (i.e., replace the steam generator lower assemblies). Three new Model 51F Steam Generator lower assembly units were ordered from Westinghouse. Virginia Power contracted Bechtel Power Corporation to provide the engineering and construction support to repair the Unit 1 steam generators. On January 4, 1993, after an extended coastdown period, North Anna Unit 1 was brought off-line and the 110 day (breaker-to-breaker) Steam Generator Replacement Project (SGRP) outage began. As of this paper, the outage is still in progress

Short-pulse optical parametric chirped-pulse amplification for the generation of high-power few-cycle pulses

International Nuclear Information System (INIS)

Major, Zs.; Osterhoff, J.; Hoerlein, R.; Karsch, S.; Fuoloep, J.A.; Krausz, F.; Ludwig-Maximilians Universitaet, Muenchen

2006-01-01

Complete test of publication follows. In the quest for a way to generate ultrashort, high-power, few-cycle laser pulses the discovery of optical parametric amplification (OPA) has opened up to the path towards a completely new regime, well beyond that of conventional laser amplification technology. The main advantage of this parametric amplification process is that it allows for an extremely broad amplification bandwidth compared to any known laser amplifier medium. When combined with the chirped-pulse amplification (CPA) principle (i.e. OPCPA), on one hand pulses of just 10 fs duration and 8 mJ pulse energy have been demonstrated. On the other hand, pulse energies of up to 30 J were also achieved on a different OPCPA system; the pulse duration in this case, however, was 100 fs. In order to combine ultrashort pulse durations (i.e. pulses in the few-cycle regime) with high pulse energies (i.e. in the Joule range) we propose tu pump on OPCPA chain with TW-scale short pulses (100 fs - 1 ps instead of > 100 ps of previous OPCPA systems) delivered by a conventional CPA system. This approach inherently improves the conditions for generating high-power ultrashort pulses using OPCPA in the following ways. Firstly, the short pump pulse duration reduces the necessary stretching factor for the seed pulse, thereby increasing stretching and compression fidelity. Secondly, also due to the shortened pump pulse duration, a much higher contrast is achieved. Finally, the significantly increased pump power makes the use of thinner OPCPA crystals possible, which implies an even broader amplification bandwidth, thereby allowing for even shorter pulses. We carried out theoretical investigations to show the feasibility of such a set-up. Alongside these studies we will also present preliminary experimental results of an OPCPA system pumped by the output of our Ti:Sapphire ATLAS laser, currently delivering 350 mJ in 43 fs. An insight into the planned scaling of this technique to petawatt

Miniature Gas-Turbine Power Generator

Science.gov (United States)

Wiberg, Dean; Vargo, Stephen; White, Victor; Shcheglov, Kirill

2003-01-01

A proposed microelectromechanical system (MEMS) containing a closed- Brayton-cycle turbine would serve as a prototype of electric-power generators for special applications in which high energy densities are required and in which, heretofore, batteries have been used. The system would have a volume of about 6 cm3 and would operate with a thermal efficiency >30 percent, generating up to 50 W of electrical power. The energy density of the proposed system would be about 10 times that of the best battery-based systems now available, and, as such, would be comparable to that of a fuel cell. The working gas for the turbine would be Xe containing small quantities of CO2, O2, and H2O as gaseous lubricants. The gas would be contained in an enclosed circulation system, within which the pressure would typically range between 5 and 50 atm (between 0.5 and 5 MPa). The heat for the Brayton cycle could be supplied by any of a number of sources, including a solar concentrator or a combustor burning a hydrocarbon or other fuel. The system would include novel heat-transfer and heat-management components. The turbine would be connected to an electric power generator/starter motor. The system would include a main rotor shaft with gas bearings; the bearing surfaces would be made of a ceramic material coated with nanocrystalline diamond. The shaft could withstand speed of 400,000 rpm or perhaps more, with bearing-wear rates less than 10(exp -)4 those of silicon bearings and 0.05 to 0.1 those of SiC bearings, and with a coefficient of friction about 0.1 that of Si or SiC bearings. The components of the system would be fabricated by a combination of (1) three-dimensional xray lithography and (2) highly precise injection molding of diamond-compatible metals and ceramic materials. The materials and fabrication techniques would be suitable for mass production. The disadvantages of the proposed system are that unlike a battery-based system, it could generate a perceptible amount of sound, and

'Crud' detection and evaluation during the Embalse nuclear power plant's thermal cycle for powers of 100%

International Nuclear Information System (INIS)

Fernandez, A.; Rosales, A.H.; Mura, V.R.; Sentupery, C.; Rascon, H.

1987-01-01

This paper describes the 'crud' measurements performed during the Embalse nuclear power plant's thermal cycle for a power of 100% (645 MWe) under different purification conditions. The aim of this work is to optimize the four steam generators' tube plate cleaning in function of the sweeping produced by their purification. (Author)

Electric power generation and uranium management

International Nuclear Information System (INIS)

Szergenyi, Istvan

1989-01-01

Assuming the present trend of nuclear power generation growth, the ratio of nuclear energy in the world power balance will double by the turn of the century. The time of reasonably exploited uranium resources can be predicted as a few decades. Therefore, new nuclear reactor types and more rational uranium management is needed to prolong life of known uranium resources. It was shown how can a better uranium utilization be expected by closed fuel cycles, and what advantages in uranium management can be expected by a better co-operation between small countries and big powers. (R.P.) 16 refs.; 4 figs

Thermodynamic performance optimization of a combined power/cooling cycle

International Nuclear Information System (INIS)

Pouraghaie, M.; Atashkari, K.; Besarati, S.M.; Nariman-zadeh, N.

2010-01-01

A combined thermal power and cooling cycle has already been proposed in which thermal energy is used to produce work and to generate a sub-ambient temperature stream that is suitable for cooling applications. The cycle uses ammonia-water mixture as working fluid and is a combination of a Rankine cycle and absorption cycle. The very high ammonia vapor concentration, exiting turbine under certain operating conditions, can provide power output as well as refrigeration. In this paper, the goal is to employ multi-objective algorithms for Pareto approach optimization of thermodynamic performance of the cycle. It has been carried out by varying the selected design variables, namely, turbine inlet pressure (P h ), superheater temperature (T superheat ) and condenser temperature (T condensor ). The important conflicting thermodynamic objective functions that have been considered in this study are turbine work (w T ), cooling capacity (q cool ) and thermal efficiency (η th ) of the cycle. It is shown that some interesting and important relationships among optimal objective functions and decision variables involved in the combined cycle can be discovered consequently. Such important relationships as useful optimal design principles would have not been obtained without the use of a multi-objective optimization approach.

Prospective analysis of energy security: A practical life-cycle approach focused on renewable power generation and oriented towards policy-makers

International Nuclear Information System (INIS)

García-Gusano, Diego; Iribarren, Diego; Garraín, Daniel

2017-01-01

Highlights: • Formulation and application of the Renewable Energy Security Index (RESI). • Prospective analysis combining Energy Systems Modelling and Life Cycle Assessment. • Feasibility proven through two case studies of power generation in Spain and Norway. • Good coverage of key energy security aspects (availability, affordability, etc.). • Novel and easy-to-report index suitable for energy policy-making. - Abstract: Energy security is a wide-ranging term to encompass issues such as security of supply, reliability of infrastructures, affordability and environmental friendliness. This article develops a robust indicator – the Renewable Energy Security Index, RESI – to enrich the body of knowledge associated with the presence of renewable energy technologies within national electricity production mixes. RESI is built by combining environmental life cycle assessment and techno-economic energy systems modelling. Spain and Norway are used as illustrative case studies for the prospective analysis of power generation from an energy security standpoint. In the Spanish case, with a diversified electricity production mix and a growing presence of renewable technologies, RESI favourably “evolves” from 0.36 at present to 0.65 in 2050 in a business-as-usual scenario, reaching higher values in a highly-restricted CO_2 scenario. The Norwegian case study attains RESI values similar to 1 due to the leading role of renewable electricity (mainly hydropower) regarding both satisfaction of national demand and exportation of electricity surplus. A widespread use of RESI as a quantifiable energy security index of national power generation sectors is found to be feasible and practical for both analysts and energy policy-makers, covering a significant number of energy security aspects.

Optimum heat power cycles for specified boundary conditions

International Nuclear Information System (INIS)

Ibrahim, O.M.; Klein, S.A.; Mitchell, J.W.

1991-01-01

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 T L.in /φT H.in where φ is a factor relating the entropy changes during heat rejection and heat addition

Performance comparison of different thermodynamic cycles for an innovative central receiver solar power plant

Science.gov (United States)

Reyes-Belmonte, Miguel A.; Sebastián, Andrés; González-Aguilar, José; Romero, Manuel

2017-06-01

The potential of using different thermodynamic cycles coupled to a solar tower central receiver that uses a novel heat transfer fluid is analyzed. The new fluid, named as DPS, is a dense suspension of solid particles aerated through a tubular receiver used to convert concentrated solar energy into thermal power. This novel fluid allows reaching high temperatures at the solar receiver what opens a wide range of possibilities for power cycle selection. This work has been focused into the assessment of power plant performance using conventional, but optimized cycles but also novel thermodynamic concepts. Cases studied are ranging from subcritical steam Rankine cycle; open regenerative Brayton air configurations at medium and high temperature; combined cycle; closed regenerative Brayton helium scheme and closed recompression supercritical carbon dioxide Brayton cycle. Power cycle diagrams and working conditions for design point are compared amongst the studied cases for a common reference thermal power of 57 MWth reaching the central cavity receiver. It has been found that Brayton air cycle working at high temperature or using supercritical carbon dioxide are the most promising solutions in terms of efficiency conversion for the power block of future generation by means of concentrated solar power plants.

Aeroderivative Pratt & Whitney FT8-3 gas turbine – an interesting solution for power generation

Directory of Open Access Journals (Sweden)

Sorinel-Gicu TALIF

2011-03-01

Full Text Available The intermediate load electric power stations become more and more interesting for theelectric power market in Romania. In this context, the Combined Cycle Power Plants came as a veryattractive solution. This paper presents the results of a study regarding the use of the aeroderivativePratt & Whitney FT8-3 gas turbine, available in Romania, for the electric power generation in aCombined Cycle Power Plant. It is also analyzed the Combined Heat in Power generation with FT8-3gas turbine when saturated steam or hot water are required.

Coal-fired high performance power generating system. Final report

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-08-31

As a result of the investigations carried out during Phase 1 of the Engineering Development of Coal-Fired High-Performance Power Generation Systems (Combustion 2000), the UTRC-led Combustion 2000 Team is recommending the development of an advanced high performance power generation system (HIPPS) whose high efficiency and minimal pollutant emissions will enable the US to use its abundant coal resources to satisfy current and future demand for electric power. The high efficiency of the power plant, which is the key to minimizing the environmental impact of coal, can only be achieved using a modern gas turbine system. Minimization of emissions can be achieved by combustor design, and advanced air pollution control devices. The commercial plant design described herein is a combined cycle using either a frame-type gas turbine or an intercooled aeroderivative with clean air as the working fluid. The air is heated by a coal-fired high temperature advanced furnace (HITAF). The best performance from the cycle is achieved by using a modern aeroderivative gas turbine, such as the intercooled FT4000. A simplified schematic is shown. In the UTRC HIPPS, the conversion efficiency for the heavy frame gas turbine version will be 47.4% (HHV) compared to the approximately 35% that is achieved in conventional coal-fired plants. This cycle is based on a gas turbine operating at turbine inlet temperatures approaching 2,500 F. Using an aeroderivative type gas turbine, efficiencies of over 49% could be realized in advanced cycle configuration (Humid Air Turbine, or HAT). Performance of these power plants is given in a table.

COMPARISON OF S-CO2 POWER CYCLES FOR NUCLEAR ENERGY

Directory of Open Access Journals (Sweden)

Ladislav Vesely

2016-12-01

Full Text Available The supercritical carbon dioxide (S-CO2 is a possible cooling system for the new generations of nuclear reactors and fusion reactors. The S-CO2 power cycles have several advantages over other possible coolants such as water and helium. The advantages are the compression work, which is lower than in the case of helium, near the critical point and the S-CO2 is more compact than water and helium. The disadvantage is so called Pinch point which occurs in the regenerative heat exchanger. The pinch point can be eliminated by an arrangement of the cycle or using a mixture of CO2. This paper describes the S-CO2 power cycles for nuclear fission and fusion reactors.

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

International Nuclear Information System (INIS)

Ehyaei, Mehdi A.; Tahani, Mojtaba; Ahmadi, Pouria; Esfandiari, Mohammad

2015-01-01

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

Power generation from residual industrial heat

International Nuclear Information System (INIS)

Nguyen, T.Q.; Slawnwhite, J.D.; Boulama, K.Goni

2010-01-01

Industrial plants continuously reject large amounts of thermal energy through warm liquid or gaseous effluents during normal operation. These energy losses contribute to an inflation of production costs and also threaten the environment. This paper investigates methods of recovering the residual low grade thermal energy and converting it into higher quality mechanical energy using the thermodynamic Rankine cycle principle. For the temperature range of the available thermal energy, water was shown to be a poor working fluid for the conversion system, thus several potential working fluids, including ammonia, synthetic refrigerants, and organic compounds have been considered as alternatives. A comparative analysis led to the identification of different performance evaluation criteria. For example, the water-based Rankine cycle and, to a lesser extent, the ammonia-based Rankine cycle proved to be interesting when the power generation potential per unit working fluid mass flow rate was considered. On the other hand, Rankine-like cycles using dry hydrocarbon working fluids proved much more interesting in terms of energy conversion efficiency, as well as in terms of the net mechanical power generation potential for a given heat source. All performance indicators were low at low temperatures, and improved as the primary heat source was available at higher temperatures. This paper also discusses the influence of various external and internal operating parameters, such as heat source and heat sink temperatures, turbine and pump isentropic efficiencies and the addition of an internal heat exchanger on the overall performance of the energy recovery and conversion system.

Promotion of public awareness relating nuclear power in young generation

International Nuclear Information System (INIS)

Kobayashi, Yoko

2011-01-01

Although nuclear power presents problems of waste, safety and non-proliferation, many people understand that it is an essential energy for addressing the global climate and reducing CO2. However, a vague negative-image to the radiation and nuclear power is deep-rooted among the public. Young generation is not an exception. It is very important to transfer many information from the experienced generation in the industry to young generations. In this paper, the research that applied the information intelligence to nuclear power, which involves of the nuclear fuel cycle, and the communication related activities for the social acceptance and improvement. (author)

A Selection Method for Power Generation Plants Used for Enhanced Geothermal Systems (EGS

Directory of Open Access Journals (Sweden)

Kaiyong Hu

2016-07-01

Full Text Available As a promising and advanced technology, enhanced geothermal systems (EGS can be used to generate electricity using deep geothermal energy. In order to better utilize the EGS to produce electricity, power cycles’ selection maps are generated for people to choose the best system based on the geofluids’ temperature and dryness conditions. Optimizations on double-flash system (DF, flash-organic Rankine cycle system (FORC, and double-flash-organic Rankine cycle system (DFORC are carried out, and the single-flash (SF system is set as a reference system. The results indicate that each upgraded system (DF, FORC, and DFORC can produce more net power output compared with the SF system and can reach a maximum net power output under a given geofluid condition. For an organic Rankine cycle (ORC using R245fa as working fluid, the generated selection maps indicate that using the FORC system can produce more power than using other power cycles when the heat source temperature is below 170 °C. Either DF or DFORC systems could be an option if the heat source temperature is above 170 °C, but the DF system is more attractive under a relatively lower geofluid’s dryness and a higher temperature condition.

Fundamental-frequency and load-varying thermal cycles effects on lifetime estimation of DFIG power converter

DEFF Research Database (Denmark)

Zhang, G.; Zhou, D.; Yang, J.

2017-01-01

In respect to a Doubly-Fed Induction Generator (DFIG) system, its corresponding time scale varies from microsecond level of power semiconductor switching to second level of the mechanical response. In order to map annual thermal profile of the power semiconductors, different approaches have been ...... adopted to handle the fundamental-frequency thermal cycles and load-varying thermal cycles. Their effects on lifetime estimation of the power device in the Back-to-Back (BTB) power converter are evaluated.......In respect to a Doubly-Fed Induction Generator (DFIG) system, its corresponding time scale varies from microsecond level of power semiconductor switching to second level of the mechanical response. In order to map annual thermal profile of the power semiconductors, different approaches have been...

Analysis of oxy-fuel combustion power cycle utilizing a pressurized coal combustor

OpenAIRE

Gazzino, Marco; Hong, Jongsup; Chaudhry, Gunaranjan; Brisson II, John G; Field, Randall; Ghoniem, Ahmed F

2009-01-01

Growing concerns over greenhouse gas emissions have driven extensive research into new power generation cycles that enable carbon dioxide capture and sequestration. In this regard, oxy-fuel combustion is a promising new technology in which fuels are burned in an environment of oxygen and recycled combustion gases. In this paper, an oxy-fuel combustion power cycle that utilizes a pressurized coal combustor is analyzed. We show that this approach recovers more thermal energy from the flue gases...

Theoretical analysis of a combined power and ejector refrigeration cycle using zeotropic mixture

International Nuclear Information System (INIS)

Yang, Xingyang; Zhao, Li; Li, Hailong; Yu, Zhixin

2015-01-01

Highlights: • A combined power and refrigeration cycle using zeotropic mixture is analyzed. • The cycle performances with different mixture compositions are compared. • Both exergy and parametric analysis of the combined cycle are conducted. - Abstract: A theoretical study on a combined power and ejector refrigeration cycle using zeotropic mixture isobutane/pentane is carried out. The performances of different mixture compositions are compared. An exergy analysis is conducted for the cycle. The result reveals that most exergy destruction happens in the ejector, where more than 40% exergy is lost. The heat exchange in generator causes the second largest exergy loss, larger than 28%. As the mass fraction of isobutane changes ranges from 100% to 0%, the relative exergy destruction of each component is also changing. And mixture isobutane/pentane (50/50) has the maximum exergy efficiency of 7.83%. The parametric analysis of generator temperature, condenser temperature and evaporator temperature for all the mixtures shows that, all these three thermodynamic parameters have a strong effect on the cycle performance.

Thermoeconomic optimization of a Kalina cycle for a central receiver concentrating solar power plant

DEFF Research Database (Denmark)

Modi, Anish; Kærn, Martin Ryhl; Andreasen, Jesper Graa

2016-01-01

with direct vapour generation and without storage. The use of the ammonia-water mixture as the power cycle working fluid with non-isothermal evaporation and condensation presents the potential to improve the overall performance of the plant. This however comes at a price of requiring larger heat exchangers...... because of lower thermal pinch and heat transfer degradation for mixtures as compared with using a pure fluid in a conventional steam Rankine cycle, and the necessity to use a complex cycle arrangement. Most of the previous studies on the Kalina cycle focused solely on the thermodynamic aspects......Concentrating solar power plants use a number of reflecting mirrors to focus and convert the incident solar energy to heat, and a power cycle to convert this heat into electricity. This paper evaluates the use of a high temperature Kalina cycle for a central receiver concentrating solar power plant...

Mapping the impacts of thermoelectric power generation: a global, spatially explicit database

Science.gov (United States)

Raptis, Catherine; Pfister, Stephan

2017-04-01

Thermoelectric power generation is associated with environmental pressures resulting from emissions to air and water, as well as water consumption. The need to achieve global coverage in related studies has become pressing in view of climate change. At the same time, the ability to quantify impacts from power production on a high resolution remains pertinent, given their highly regionalized nature, particularly when it comes to water-related impacts. Efforts towards global coverage have increased in recent years, but most work on the impacts of global electricity production presents a coarse geographical differentiation. Over the past few years we have begun a concerted effort to create and make available a global georeferenced inventory of thermoelectric power plant operational characteristics and emissions, by modelling the relevant processes on the highest possible level: that of a generating unit. Our work extends and enhances a commercially available global power plant database, and so far includes: - Georeferencing the generating units and populating the gaps in their steam properties. - Identifying the cooling system for 92% of the global installed thermoelectric power capacity. - Using the completed steam property data, along with local environmental temperature data, to systematically solve the Rankine cycle for each generating unit, involving: i) distinguishing between simple, reheat, and cogenerative cycles, and accounting for particularities in nuclear power cycles; ii) accounting for the effect of different cooling systems (once-through, recirculating (wet tower), dry cooling) on the thermodynamic cycle. One of the direct outcomes of solving the Rankine cycle is the cycle efficiency, an indispensable parameter in any study related to power production, including the quantification of air emissions and water consumption. Another direct output, for those units employing once-through cooling, is the rate of heat rejection to water, which can lead to

Combined cycle versus one thousand diesel power plants: pollutant emissions, ecological efficiency and economic analysis

International Nuclear Information System (INIS)

Silveira, Jose Luz; de Carvalho, Joao Andrade; de Castro Villela, Iraides Aparecida

2007-01-01

The increase in the use of natural gas in Brazil has stimulated public and private sectors to analyse the possibility of using combined cycle systems for generation of electrical energy. Gas turbine combined cycle power plants are becoming increasingly common due to their high efficiency, short lead times, and ability to meet environmental standards. Power is produced in a generator linked directly to the gas turbine. The gas turbine exhaust gases are sent to a heat recovery steam generator to produce superheated steam that can be used in a steam turbine to produce additional power. In this paper a comparative study between a 1000 MW combined cycle power plant and 1000kW diesel power plant is presented. In first step, the energetic situation in Brazil, the needs of the electric sector modification and the needs of demand management and integrated means planning are clarified. In another step the characteristics of large and small thermoelectric power plants that use natural gas and diesel fuel, respectively, are presented. The ecological efficiency levels of each type of power plant is considered in the discussion, presenting the emissions of particulate material, sulphur dioxide (SO 2 ), carbon dioxide (CO 2 ) and nitrogen oxides (NO x ). (author)

Hybrid biomass-wind power plant for reliable energy generation

International Nuclear Information System (INIS)

Perez-Navarro, A.; Alfonso, D.; Alvarez, C.; Ibanez, F.; Sanchez, C.; Segura, I.

2010-01-01

Massive implementation of renewable energy resources is a key element to reduce CO 2 emissions associated to electricity generation. Wind resources can provide an important alternative to conventional electricity generation mainly based on fossil fuels. However, wind generators are greatly affected by the restrictive operating rules of electricity markets because, as wind is naturally variable, wind generators may have serious difficulties on submitting accurate generation schedules on a day ahead basis, and on complying with scheduled obligations in real-time operation. In this paper, an innovative system combining a biomass gasification power plant, a gas storage system and stand-by generators to stabilize a generic 40 MW wind park is proposed and evaluated with real data. The wind park power production model is based on real data about power production of a Spanish wind park and a probabilistic approach to quantify fluctuations and so, power compensation needs. The hybrid wind-biomass system is analysed to obtain main hybrid system design parameters. This hybrid system can mitigate wind prediction errors and so provide a predictable source of electricity. An entire year cycle of hourly power compensations needs has been simulated deducing storage capacity, extra power needs of the biomass power plant and stand-by generation capacity to assure power compensation during critical peak hours with acceptable reliability. (author)

Investigating the effect of several thermodynamic parameters on exergy destruction in components of a tri-generation cycle

International Nuclear Information System (INIS)

Salehzadeh, A.; Khoshbakhti Saray, R.; JalaliVahid, D.

2013-01-01

Multiple energy generating cycles such as tri-generation cycles, which produce heat and cold in addition to power through burning of a primary fuel, have increasingly been used in recent decades. On the other hand, advanced exergy analysis of thermodynamic systems by splitting exergy destruction into endogenous and exogenous parts identifies internal irreversibilities of each of the components and the effect of these irreversibilities on the performance of other components. Therefore, main sources of exergy destruction in cycles can be highlighted and useful recommendations in order to improve the performance of thermodynamic cycles can be presented. In the present work, a tri-generation cycle with 100 MW power production, 70 MW heat and 9 MW cooling capacity is considered. For this tri-generation cycle, effects of various thermodynamic parameters on the amount of endogenous and exogenous exergy destructions, exergy loss and the amount of fuel consumption, are investigated. The results indicate that, increasing compressor pressure ratio, pre-heater outlet temperature and excess air leads to better combustion and lower exergy loss and fuel consumption. Increasing the mass flow rate of steam generator, while keeping the cycle outlet temperature constant and considering cooling capacity variable, lead to increase the first- and second-law efficiencies of the cycle. - Highlights: ► Advanced exergy analysis is used to analyze a tri-generation cycle. ► Increasing compressor pressure ratio leads to lower exergy loss and fuel consumption. ► Exergy loss is lowered by increasing pre-heater outlet temperature. ► Increasing the air flow rate of the cycle improves the performance of the cycle

Evaluation of the energy efficiency of combined cycle gas turbine. Case study of Tashkent thermal power plant, Uzbekistan

International Nuclear Information System (INIS)

Aminov, Zarif; Nakagoshi, Nobukazu; Xuan, Tran Dang; Higashi, Osamu; Alikulov, Khusniddin

2016-01-01

Highlights: • The combined cycle power plant (CCPP) has a steam turbine and a gas turbine. • Fossil fuel savings and reduction of the CCGT of was evaluated. • The performance of a three pressure CCGT is modelled under different modes. • Energy efficiency of the combined cycle was 58.28%. • An annual reduction of 1760.18 tNO_x/annum and 981.25 ktCO_2/annum can be achieved. - Abstract: The power generation of Tashkent Thermal Power Plant (TPP) is based on conventional power units. Moreover, the facility suffers from limited efficiency in electricity generation. The plant was constructed during the Soviet era. Furthermore, the power plant is being used for inter-hour power generation regulation. As a result, the efficiency can be reduced by increasing specific fuel consumption. This research focuses on the evaluation of the energy efficiency of the combined cycle gas turbine (CCGT) for the Tashkent TPP. Specifically, the objective is an evaluation of fossil fuel savings and reduction of CO_2 and NO_x emissions with the using CCGT technology at conventional power plant. The proposed combined cycle power plant (CCPP) includes an existing steam turbine (ST) with 160 MW capacity, heat recovery steam generator (HRSG), and gas turbine (GT) technology with 300 MW capacity. The performance of a three pressure CCGT is modelled under different modes. As a result, the efficiency of the combined cycle was evaluated at 58.28%, while the conventional cycle had an efficiency of 34.5%. We can achieve an annual reduction of 1760.18 tNO_x/annum and 981.25 ktCO_2/annum.

Improvement in recuperative gas cycles by means of a heat generator partly by-passing the recuperator. Application to open and closed cycles and to various kinds of energy

International Nuclear Information System (INIS)

Tilliette, Z.P.; Pierre, B.

1979-01-01

A particular arrangement applicable to open or closed recuperative gas cycles and consisting of a heat generator partly by-passing the low pressure side of the recuperator is proven to enhance advantages of gas cycles for energy production. The cogeneration of both power with a high efficiency owing to the recuperator and high temperature process heat becomes possible and economically attractive. Furthermore, additional possibilities appear for power generation by combined gas and steam or ammonia cycles. In any case the overall utilization coefficient of the primary energy is increased and the combined production of low or medium temperature heat can also be improved. The great operation flexibility of the system for combined energy generation is worth being emphasized: the by-pass arrangement involves no significant change in the operation conditions of the main turbocompressor as the heat output varies. Applications of this arrangement are made to: - open and closed gas cycle, power plants; - fossil, nuclear and solar energies. The overall heat conversion efficiency is tentatively estimated in order to appreciate the energy conversion capability of the investigated power plants

Sensitivity analysis of molecular design problem for the development of novel working fluids for power cycles

DEFF Research Database (Denmark)

Frutiger, Jerome; Abildskov, Jens; Sin, Gürkan

. Multi-criteria database search and Computer Aided Molecular Design (CAMD) can be applied to generate, test and evaluate promising pure component/mixture candidate as process fluids to help optimize cycle design and performance [1]. The problem formulation for the development of novel working fluids...... a certain working fluid property parameter on the performance of the power cycle, i.e. the net power output, can facilitate the identification key properties for working fluids. In that sense a sensitivity analysis of the different parameters is suggested in this work as a systematic method to efficiently...... technology to convert such waste heat sources into usable energy. So far the low-temperature heat is not utilized efficiently for electricity generation. To optimize the heat transfer process and the power generation, the influence of the working fluid, the cycle designs and the operating conditions is vital...

Present status and problems of nuclear power generation

International Nuclear Information System (INIS)

Harada, Hiroshi.

1984-01-01

The nuclear power generation in Japan began in 1963 with the successful power generation in the JPDR of the Japan Atomic Energy Research Institute, and since then, more than 20 years have elapsed. The Japan Atomic Power Co. started the operation of an imported Calder Hall type gas-cooled reactor with 166,000 kWe output in Tokai Nuclear Power Station in July, 1966. In 1983, the quantity of nuclear power generation was 113.1 billion kWh, which was equivalent to 21.4 % of the total power generation in Japan. As of April 1, 1984, 25 nuclear power plants with 18.28 million kW output were in operation, 12 plants of 11.8 million kW were under construction, and 7 plants of 6.05 million kW were in preparation phase. Besides, the ATR ''Fugen'' with 165,000 kW output has been in operation, and the FBR ''Monju'' with 280,000 kW output is under construction. The capacity ratio of Japanese nuclear power stations attained 71.5 % in 1983. According to the ''Long term energy demand and supply outlook'' revised in November, 1983, the nuclear power generation in 2000 will be about 62 million kW to cater for about 16 % of primary energy supply. The problems are the improvement of economy, the establishment of independent nuclear fuel cycle, the decommissioning of nuclear reactors and so on. (Kako, I.)

Global analysis of a renewable micro hydro power generation plant

Science.gov (United States)

Rahman, Md. Shad; Nabil, Imtiaz Muhammed; Alam, M. Mahbubul

2017-12-01

Hydroelectric power or Hydropower means the power generated by the help of flowing water with force. It is one the best source of renewable energy in the world. Water evaporates from the earth's surface, forms clouds, precipitates back to earth, and flows toward the ocean. Hydropower is considered a renewable energy resource because it uses the earth's water cycle to generate electricity. As far as Global is concerned, only a small fraction of electricity is generated by hydro-power. The aim of our analysis is to demonstrate and observe the hydropower of the Globe in micro-scale by our experimental setup which is completely new in concept. This paper consists of all the Global and National Scenario of Hydropower. And how we can more emphasize the generation of Hydroelectric power worldwide.

Problems of coal-based power generation

International Nuclear Information System (INIS)

Noskievic, P.

1996-01-01

Current problems of and future trends in coal-based power generation are discussed. The present situation is as follows: coal, oil and gas contribute to world fossil fuel resources 75%, 14%, and 11%, respectively, and if the current trend will continue, will be depleted in 240, 50, and 60 years, respectively; the maximum resource estimates (including resources that have not yet been discovered) are 50% higher for oil and 100% higher for gas, for coal such estimates have not been made. While the world prices of coal are expected to remain virtually constant, the prices of gas will probably increase to be twice as high in 2010. Thus, the role of coal may be higher in the next century than it is now, provided that due attention is paid to improving the efficiency of coal-fired power plants and reducing their adverse environmental effects. A comparison of economic data for coal-fired and gas-fired power plants is as follows: Investment cost (USD/kW): 1400, 800; fixed running cost (USD/kW.y): 33.67, 9.0; variable running cost (USD/kWh): 0.30, 0.15; power use (kJ/kWh): 10.29, 7.91; annual availability (%): 70, 50; fuel price (USD/GJ): 1.00, 4.30; power price (USD/kWh): 4.28, 5.52. The investment cost for coal-fired plants covers new construction including flue gas purification. The integrated gasification combined cycle (IGCC) seems to be the future of coal-based power generation. The future problems to be addressed include ways to reduce air pollution, improving the efficiency of the gas-steam cycle, and improving the combustion process particularly with a view to reducing substantially its environmental impact. (P.A.). 4 figs., 4 tabs., 9 refs

The P3 Power Generation System for Advanced Missile Defense Applications

Science.gov (United States)

2008-11-01

circuit. This increased the output power to the load resistor . The inductor couples with the piezo element to form an electrical LC tuned circuit and...of RMS power was generated with an efficiency of 40 % when an inductor of 250 mH was connected in series to a 100 ohm resistor . From power density...per cycle for generating electrical energy in a piezo -crystal membrane. Steady-state heat transfer measurements have been made previously with a

Gas-fired electric power generating technologies

International Nuclear Information System (INIS)

1994-09-01

The workshop that was held in Madrid 25-27 May 1994 included participation by experts from 16 countries. They represented such diverse fields and disciplines as technology, governmental regulation, economics, and environment. Thus, the participants provided an excellent cross section of key areas and a diversity of viewpoints. At the workshop, a broad range of topics regarding gas-fired electric power generation was discussed. These included political, regulatory and financial issues as well as more specific technical questions regarding the environment, energy efficiency, advanced generation technologies and the status of competitive developments. Important technological advances in gas-based power and CHP technologies have already been achieved including higher energy efficiency and lower emissions, with further improvements expected in the near future. Advanced technology trends include: (a) The use of gas technology to reduce emissions from existing coal-fired power plants. (b) The wide-spread application of combined-cycle gas turbines in new power plants and the growing use of aero-derivative gas turbines in CHP applications. (c) Phosphoric acid fuel cells that are being introduced commercially. Their market penetration will grow over the next 10 years. The next generation of fuel cells (solid oxide and molten carbonate) is expected to enter the market around the year 2000. (EG)

Multiple regression approach to predict turbine-generator output for Chinshan nuclear power plant

International Nuclear Information System (INIS)

Chan, Yea-Kuang; Tsai, Yu-Ching

2017-01-01

The objective of this study is to develop a turbine cycle model using the multiple regression approach to estimate the turbine-generator output for the Chinshan Nuclear Power Plant (NPP). The plant operating data was verified using a linear regression model with a corresponding 95% confidence interval for the operating data. In this study, the key parameters were selected as inputs for the multiple regression based turbine cycle model. The proposed model was used to estimate the turbine-generator output. The effectiveness of the proposed turbine cycle model was demonstrated by using plant operating data obtained from the Chinshan NPP Unit 2. The results show that this multiple regression based turbine cycle model can be used to accurately estimate the turbine-generator output. In addition, this study also provides an alternative approach with simple and easy features to evaluate the thermal performance for nuclear power plants.

Multiple regression approach to predict turbine-generator output for Chinshan nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

Chan, Yea-Kuang; Tsai, Yu-Ching [Institute of Nuclear Energy Research, Taoyuan City, Taiwan (China). Nuclear Engineering Division

2017-03-15

The objective of this study is to develop a turbine cycle model using the multiple regression approach to estimate the turbine-generator output for the Chinshan Nuclear Power Plant (NPP). The plant operating data was verified using a linear regression model with a corresponding 95% confidence interval for the operating data. In this study, the key parameters were selected as inputs for the multiple regression based turbine cycle model. The proposed model was used to estimate the turbine-generator output. The effectiveness of the proposed turbine cycle model was demonstrated by using plant operating data obtained from the Chinshan NPP Unit 2. The results show that this multiple regression based turbine cycle model can be used to accurately estimate the turbine-generator output. In addition, this study also provides an alternative approach with simple and easy features to evaluate the thermal performance for nuclear power plants.

Summary of nuclear power and fuel cycle data in OECD member countries

International Nuclear Information System (INIS)

1986-04-01

A questionnaire on Electricity Generation, Nuclear Power and Fuel Cycle Data is distributed annually to OECD Member Countries. In the questionnaire of January 1986, countries were asked to provide historical data for 1984 and 1985 and most likely projections up to the year 2005. The replies to the questionnaire are presented in this Summary. Not all countries have revised or made new projections since the April 1985 issue. Too few countries were able to provide projections beyond 2000 to include data for 2005 in this year's Summary. Data for 1985 are in some cases provisional. Where no data were available the Secretariat made estimates, based on information of IEA, IAEA, the previous Brown Book, OECD/IEA Energy Statistics and other sources. The electricity generation and production data for fuel cycle services refer to those facilities located within the country, and thus exclude imports. The fuel cycle requirements, however, refer to the amounts of fuel cycle services necessary for national nuclear power programmes. The Addendum contains an analysis of the present and past projections for OECD nuclear capacity to 2000

Method and apparatus for thermal power generation

International Nuclear Information System (INIS)

Mangus, J.D.

1979-01-01

A method is described for power generation from a recirculating superheat-reheat circuit with multiple expansion stages which alleviates complex control systems and minimizes thermal cycling of system components, particularly the reheater. The invention includes preheating cold reheat fluid from the first expansion stage prior to its entering the reheater with fluid from the evaporator or drum component

Ammonium generation during SRAT cycle

International Nuclear Information System (INIS)

Hsu, C.W.

1992-01-01

During the IDMS noble-metal demonstration runs ammonium nitrate deposition was found in the vessel vent system of the feed preparation area. In the bench-scale experiments of studying the hydrogen generation during the sludge treatment cycle, ammonium ion production was also monitored. It was found that: During a simulation of the DWPF Cold Chemical Runs SRAT cycle no detectable amount of ammonium ions was generated when treating a non-noble-metal containing sludge simulant according to the nitric acid flowsheet. Ammonium ions were generated during the SRAT-SME cycle when treating the noble-metal containing sludge with either formic acid or nitric acid/late-washing PHA. This is due to the reaction between formic acid and nitrate catalyzed by the noble metals in the sludge simulant. Ammonium ion production closely followed the hydrogen evolution from the catalytic decomposition of formic acid. This report summarizes the results of the production of ammonia during the SRAT cycle

Noncircular Chainrings Do Not Influence Maximum Cycling Power.

Science.gov (United States)

Leong, Chee-Hoi; Elmer, Steven J; Martin, James C

2017-12-01

Noncircular chainrings could increase cycling power by prolonging the powerful leg extension/flexion phases, and curtailing the low-power transition phases. We compared maximal cycling power-pedaling rate relationships, and joint-specific kinematics and powers across 3 chainring eccentricities (CON = 1.0; LOW ecc  = 1.13; HIGH ecc  = 1.24). Part I: Thirteen cyclists performed maximal inertial-load cycling under 3 chainring conditions. Maximum cycling power and optimal pedaling rate were determined. Part II: Ten cyclists performed maximal isokinetic cycling (120 rpm) under the same 3 chainring conditions. Pedal and joint-specific powers were determined using pedal forces and limb kinematics. Neither maximal cycling power nor optimal pedaling rate differed across chainring conditions (all p > .05). Peak ankle angular velocity for HIGH ecc was less than CON (p pedal system allowed cyclists to manipulate ankle angular velocity to maintain their preferred knee and hip actions, suggesting maximizing extension/flexion and minimizing transition phases may be counterproductive for maximal power.

Multimegawatt space nuclear power open-cycle MHD-facility

International Nuclear Information System (INIS)

Pavshuk, V.A.; Panchenko, V.P.

2008-01-01

Paper presents the results of the efforts to calculate the characteristics, the layout and the engineering design of the open cycle space power propulsion on the basis of the high-temperature nuclear reactor for a nuclear rocket engine and the Faraday 20 MW capacity MHD-generator. The IVG-1 heterogeneous channel-vessel reactor ensuring in the course of the experiments hydrogen heating up to 3100 K, up to 5 MPa pressure at the reactor core outlet, up to 5 kg/s flowsheet, up to 220 MW thermal power served as a reactor is considered. One determined the MHD-generator basic parameters, namely: the portion of Cs dope was equal to 20%, the outlet stagnation pressure - 2 MPa, the electric conductivity - ≅30 S/m, the Mach number - ≅0.7, the magnetic field induction - 6 T, the capacity - 20 MW, the specific power removal - ∼4 MJ/kg. Paper describes the design of the MHD-facility with the working fluid momentless discharge and its basic characteristics [ru

Integration between a thermophotovoltaic generator and an Organic Rankine Cycle

International Nuclear Information System (INIS)

De Pascale, Andrea; Ferrari, Claudio; Melino, Francesco; Morini, Mirko; Pinelli, Michele

2012-01-01

Highlights: ► A new energy system comprising a Thermo-Photo-Voltaic and Organic Rankine Cycle. ► An analytical model to calculate the performance of the system is introduced. ► The system shows promising results in terms of CHP performance. -- Abstract: The constant increase in energy need and the growing attention to the related environmental impact have given a boost to the development of new strategies in order to reduce the primary energy consumption and to improve its utilization. One of the possible strategies for achieving this aim is Combined Heat and Power (CHP) specially if coupled with the concept of on-site generation (also known as distributed generation). These approaches allow the reduction of fuel consumption and pollutant emissions and the increase of security in energy supply. This paper introduces the Thermophotovoltaic Organic Rankine Cycle Integrated System (TORCIS), an energy system integrating a ThermoPhotoVoltaic generator (TPV) and an Organic Rankine Cycle (ORC). This study represents the start-up of a research program which involves three research teams from IMEM – National Research Council, ENDIF – University of Ferrara and DIEM – University of Bologna. The aim of this research is the complete definition and the pre-prototyping characterization of this system covering all the unresolved issues in this field. More specifically, TPV is a system to convert the radiation emitted from an artificial heat source (i.e. the combustion of fuel) into electrical energy by the use of photovoltaic cells. In this system, the produced electrical power is strictly connected to the thermal one as their ratio is almost constant and cannot be changed without severe loss in performance. The coupling between TPV and ORC allows this limitation to be overcome by the realization of a CHP system which can be regulated with a large degree of freedom changing the ratio between the produced electrical and thermal power. In this study a thermodynamic

Life cycle assessment of electricity generation in Mexico

International Nuclear Information System (INIS)

Santoyo-Castelazo, E.; Gujba, H.; Azapagic, A.

2011-01-01

This paper presents for the first time a Life Cycle Assessment (LCA) study of electricity generation in Mexico. The electricity mix in Mexico is dominated by fossil fuels, which contribute around 79% to the total primary energy; renewable energies contribute 16.5% (hydropower 13.5%, geothermal 3% and wind 0.02%) and the remaining 4.8% is from nuclear power. The LCA results show that 225 TWh of electricity generate about 129 million tonnes of CO 2 eq. per year, of which the majority (87%) is due to the combustion of fossil fuels. The renewables and nuclear contribute only 1.1% to the total CO 2 eq. Most of the other LCA impacts are also attributed to the fossil fuel options. The results have been compared with values reported for other countries with similar electricity mix, including Italy, Portugal and the UK, showing good agreement. -- Highlights: → This paper presents for the first time a Life Cycle Assessment (LCA) study of electricity generation in Mexico. → 129 million tonnes of CO 2 eq. per year are emitted from 225 TWh of electricity generated per year of which 87% is due to the combustion of fossil fuels. → Coal technologies generate 1094 g CO 2 eq./kWh, heavy fuel oil 964 g CO 2 eq./kWh, and gas 468 g CO 2 eq./kWh; by contrast, nuclear and hydro emit 12 g CO 2 eq./kWh. → Heavy fuel oil contributes most to the life cycle environmental impacts (59-97%). → The results show good agreement with values reported for other countries with similar electricity mix, including Italy, Portugal and the UK.

Combustion technology developments in power generation in response to environmental challenges

Energy Technology Data Exchange (ETDEWEB)

BeerBeer, J.M. [Massachusetts Inst. of Technology, Dept. of Chemical Engineering, Cambridge, MA (United States)

2000-07-01

greenhouse gas debate. This is adding the task of raising the thermodynamic efficiency of the power generating cycle to the existing demands for reduced pollutant emission. Reassessment of the long-term availability of natural gas, and the development of low NO{sub x} and highly efficient gas turbine-steam combined cycles made this mode of power generation greatly attractive also for base load operation. However, the real prize and challenge of power generation R&D remains to be the development of highly efficient and clean coal-fired systems. The most promising of these include pulverised coal combustion in a supercritical steam boiler, pressurised fluid bed combustion without or with topping combustion, air heater gas turbine-steam combined cycle, and integrated gasification combined cycle. In the longer term, catalytic combustion in gas turbines and coal gasification-fuel cell systems hold out promise for even lower emissions and higher thermodynamic cycle efficiency. The present state of these advanced power-generating cycles together with their potential for application in the near future is discussed, and the key role of combustion science and technology as a guide in their continuing development highlighted. (Author)

Uranium oxide recycling to give more sustainable power generation

International Nuclear Information System (INIS)

Hagger, R.; Garner, D.S.J.; Beaumont, D.M.; Hesketh, K.

2001-01-01

In broad terms there are two routes for irradiated nuclear fuel, the closed cycle involving recycling and the open cycle culminating in direct disposal. The benefits of following the closed cycle are presented. The environmental burdens associated with open and closed cycles are compared using Life Cycle Assessment (LCA) for non-active burdens and human irradiation. Consideration is given to the extension of the nuclear fuel cycle to include a proportion of MOX fuel elements within a reactor core, and the impact in terms of total activity, waste volumes and Integrated Toxic Potential (ITP) discussed. The potential of moving to a fast reactor cycle is also raised in support of the recycling of spent nuclear fuel giving sustainable power generation. (author)

Development of Natural Gas Fired Combined Cycle Plant for Tri-Generation of Power, Cooling and Clean Water Using Waste Heat Recovery: Techno-Economic Analysis

OpenAIRE

Mohan, Gowtham; Dahal, Sujata; Kumar, Uday; Martin, Andrew; Kayal, Hamid

2014-01-01

Tri-generation is one of the most efficient ways for maximizing the utilization of available energy. Utilization of waste heat (flue gases) liberated by the Al-Hamra gas turbine power plant is analyzed in this research work for simultaneous production of: (a) electricity by combining steam rankine cycle using heat recovery steam generator (HRSG); (b) clean water by air gap membrane distillation (AGMD) plant; and (c) cooling by single stage vapor absorption chiller (VAC). The flue gases liber...

Power generation from low-temperature heat source

Energy Technology Data Exchange (ETDEWEB)

Lakew, Amlaku Abie

2012-07-01

transcritical power cycle is operating at lower pump efficiency, the effect of a decrease in pump efficiency is equivalent to a decrease in turbine efficiency. The thermodynamic analysis is coupled with a 1D mean line turbine design. Both axial and radial turbines are considered. The Ainely and Mathieson loss model is used in the 1D axial turbine designs. It is observed that the blade height is generally small; the reason being high operating pressure and low flow rate. A novel approach to enhance the performance of low-temperature CO{sub 2} transcritical power cycles is investigated. From the thermodynamic analysis, it is observed that the pump work is significant and reduction of pump work will be translated to a gain in net power output. The mechanical driven pump is suggested to be replaced by a thermally driven pump. The working principle of thermally driven pump is by exploiting the phenomena in which the pressure of a closed vessel filled full with saturated liquid will rise when heated. A cascade of vessels is used to make the pressurizing process continuous. The time taken to pressurize is an important parameter for the performance of thermally driven pump. Pressurizing time depends on isochoric specific heat capacity of the working fluid, heat transfer coefficient, inlet conditions of heat source, tube diameter, and initial mass of the working fluid. When the pressurizing time is longer, more vessels are required to make the process continuous. It is shown that it possible to increase power output using a thermal driven pump, but additional equipments are required. An example of a possible application is a low-temperature CO{sub 2} power cycle integrated with a post-combustion carbon dioxide capture plant. The heat rejected by low temperature streams in the capture plant is used as a heat sources for power generation. It is found that utilization of heat of the capture plant improves the performance of the overall process. It shows that low-temperature transcritical

Prediction of Chiller Power Consumption: An Entropy Generation Approach

KAUST Repository

Saththasivam, Jayaprakash

2016-06-21

Irreversibilities in each component of vapor compression chillers contribute to additional power consumption in chillers. In this study, chiller power consumption was predicted by computing the Carnot reversible work and entropy generated in every component of the chiller. Thermodynamic properties namely enthalpy and entropy of the entire refrigerant cycle were obtained by measuring the pressure and temperature at the inlet and outlet of each primary component of a 15kW R22 water cooled scroll chiller. Entropy generation of each component was then calculated using the First and Second Laws of Thermodynamics. Good correlation was found between the measured and computed chiller power consumption. This irreversibility analysis can be also effectively used as a performance monitoring tool in vapor compression chillers as higher entropy generation is anticipated during faulty operations.

User instructions for levelized power generation cost codes using an IBM-type PC

International Nuclear Information System (INIS)

Coen, J.J.; Delene, J.G.

1989-01-01

Programs for the calculation of levelized power generation costs using an IBM or compatible PC are described. Cost calculations for nuclear plants and coal-fired plants include capital investment cost, operation and maintenance cost, fuel cycle cost, decommissioning cost, and total levelized power generation cost. 7 refs., 36 figs., 4 tabs

Power plant cycle chemistry - a currently neglected power plant chemistry discipline

International Nuclear Information System (INIS)

Bursik, A.

2005-01-01

Power plant cycle chemistry seems to be a stepchild at both utilities and universities and research organizations. It is felt that other power plant chemistry disciplines are more important. The last International Power Cycle Chemistry Conference in Prague may be cited as an example. A critical review of the papers presented at this conference seems to confirm the above-mentioned statements. This situation is very unsatisfactory and has led to an increasing number of component failures and instances of damage to major cycle components. Optimization of cycle chemistry in fossil power plants undoubtedly results in clear benefits and savings with respect to operating costs. It should be kept in mind that many seemingly important chemistry-related issues lose their importance during forced outages of units practicing faulty plant cycle chemistry. (orig.)

Scheduling of Power System Cells Integrating Stochastic Power Generation

International Nuclear Information System (INIS)

Costa, L.M.

2008-12-01

Energy supply and climate change are nowadays two of the most outstanding problems which societies have to cope with under a context of increasing energy needs. Public awareness of these problems is driving political willingness to take actions for tackling them in a swift and efficient manner. Such actions mainly focus in increasing energy efficiency, in decreasing dependence on fossil fuels, and in reducing greenhouse gas emissions. In this context, power systems are undergoing important changes in the way they are planned and managed. On the one hand, vertically integrated structures are being replaced by market structures in which power systems are un-bundled. On the other, power systems that once relied on large power generation facilities are witnessing the end of these facilities' life-cycle and, consequently, their decommissioning. The role of distributed energy resources such as wind and solar power generators is becoming increasingly important in this context. However, the large-scale integration of such type of generation presents many challenges due, for instance, to the uncertainty associated to the variability of their production. Nevertheless, advanced forecasting tools may be combined with more controllable elements such as energy storage devices, gas turbines, and controllable loads to form systems that aim to reduce the impacts that may be caused by these uncertainties. This thesis addresses the management under market conditions of these types of systems that act like independent societies and which are herewith named power system cells. From the available literature, a unified view of power system scheduling problems is also proposed as a first step for managing sets of power system cells in a multi-cell management framework. Then, methodologies for performing the optimal day-ahead scheduling of single power system cells are proposed, discussed and evaluated under both a deterministic and a stochastic framework that directly integrates the

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

International Nuclear Information System (INIS)

Peng, Shuo; Hong, Hui; Jin, Hongguang; Wang, Zhifeng

2012-01-01

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/m 2 . 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.

POWER CYCLE AND STRESS ANALYSES FOR HIGH TEMPERATURE GAS-COOLED REACTOR

International Nuclear Information System (INIS)

Oh, Chang H; Davis, Cliff; Hawkes, Brian D; Sherman, Steven R

2007-01-01

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

Optimised heat recovery steam generators for integrated solar combined cycle plants

Science.gov (United States)

Peterseim, Jürgen H.; Huschka, Karsten

2017-06-01

The cost of concentrating solar power (CSP) plants is decreasing but, due to the cost differences and the currently limited value of energy storage, implementation of new facilities is still slow compared to photovoltaic systems. One recognized option to lower cost instantly is the hybridization of CSP with other energy sources, such as natural gas or biomass. Various references exist for the combination of CSP with natural gas in combined cycle plants, also known as Integrated Solar Combined Cycle (ISCC) plants. One problem with current ISCC concepts is the so called ISCC crisis, which occurs when CSP is not contributing and cycle efficiency falls below efficiency levels of solely natural gas only fired combined cycle plants. This paper analyses current ISCC concepts and compares them with two optimised designs. The comparison is based on a Kuraymat type ISCC plant and shows that cycle optimization enables a net capacity increase of 1.4% and additional daily generation of up to 7.9%. The specific investment of the optimised Integrated Solar Combined Cycle plant results in a 0.4% cost increase, which is below the additional net capacity and daily generation increase.

Test results of an organic Rankine-cycle power module for a small community solar thermal power experiment

Science.gov (United States)

Clark, T. B.

1985-01-01

The organic Rankine-cycle (ORC) power conversion assembly was tested. Qualification testing of the electrical transport subsystem was also completed. Test objectives were to verify compatibility of all system elements with emphasis on control of the power conversion assembly, to evaluate the performance and efficiency of the components, and to validate operating procedures. After 34 hours of power generation under a wide range of conditions, the net module efficiency exceeded 18% after accounting for all parasitic losses.

Comparative health and safety assessment of the satellite power system and other electrical generation alternatives

International Nuclear Information System (INIS)

1980-12-01

The work reported here is an analysis of existing data on the health and safety risks of a satellite power system and six electrical generation systems: a combined-cycle coal power system with a low-Btu gasifier and open-cycle gas turbine; a light water fission power system without fuel reprocessing; a liquid-metal, fast-breeder fission reactor; a centralized and decentralized, terrestrial, solar-photovoltaic power system; and a first-generation design for a fusion power system. The systems are compared on the basis of expected deaths and person-days lost per year associated with 1000 MW of average electricity generation. Risks are estimated and uncertainties indicated for all phases of the energy production cycle, including fuel and raw material extraction and processing, direct and indirect component manufacture, on-site construction, and system operation and maintenance. Also discussed is the potential significance of related major health and safety issues that remain largely unquantifiable. The appendices provide more detailed information on risks, uncertainties, additional research needed, and references for the identified impacts of each system

Advanced power generation using biomass wastes from palm oil mills

International Nuclear Information System (INIS)

Aziz, Muhammad; Kurniawan, Tedi; Oda, Takuya; Kashiwagi, Takao

2017-01-01

This study focuses on the energy-efficient utilization of both solid and liquid wastes from palm oil mills, particularly their use for power generation. It includes the integration of a power generation system using empty fruit bunch (EFB) and palm oil mill effluent (POME). The proposed system mainly consists of three modules: EFB gasification, POME digestion, and additional organic Rankine cycle (ORC). EFBs are dried and converted into a syngas fuel with high calorific value through integrated drying and gasification processes. In addition, POME is converted into a biogas fuel for power generation. Biogas engine-based cogenerators are used for generating both electricity and heat. The remaining unused heat is recovered by ORC module to generate electricity. The influences of three EFB gasification temperatures (800, 900 and 1000 °C) in EFB gasification module; and working fluids and pressure in ORC module are evaluated. Higher EFB gasification leads to higher generated electricity and remaining heat for ORC module. Power generation efficiency increases from 11.2 to 24.6% in case of gasification temperature is increased from 800 to 1000 °C. In addition, cyclohexane shows highest energy efficiency compared to toluene and n-heptane in ORC module. Higher pressure in ORC module also leads to higher energy efficiency. Finally, the highest total generated power and power generation efficiency obtained by the system are 8.3 MW and 30.4%, respectively.

Human health impacts in the life cycle of future European electricity generation

International Nuclear Information System (INIS)

Treyer, Karin; Bauer, Christian; Simons, Andrew

2014-01-01

This paper presents Life Cycle Assessment (LCA) based quantification of the potential human health impacts (HHI) of base-load power generation technologies for the year 2030. Cumulative Greenhouse Gas (GHG) emissions per kWh electricity produced are shown in order to provide the basis for comparison with existing literature. Minimising negative impacts on human health is one of the key elements of policy making towards sustainable development: besides their direct impacts on quality of life, HHI also trigger other impacts, e.g. external costs in the health care system. These HHI are measured using the Life Cycle Impact Assessment (LCIA) methods “ReCiPe” with its three different perspectives and “IMPACT2002+”. Total HHI as well as the shares of the contributing damage categories vary largely between these perspectives and methods. Impacts due to climate change, human toxicity, and particulate matter formation are the main contributors to total HHI. Independently of the perspective chosen, the overall impacts on human health from nuclear power and renewables are substantially lower than those caused by coal power, while natural gas can have lower HHI than nuclear and some renewables. Fossil fuel combustion as well as coal, uranium and metal mining are the life cycle stages generating the highest HHI. - Highlights: • Life cycle human health impacts (HHI) due to electricity production are analysed. • Results are shown for the three ReCiPe perspectives and IMPACT2002+LCIA method. • Total HHI of nuclear and renewables are much below those of fossil technologies. • Climate change and human toxicity contribute most to total HHI. • Fossil fuel combustion and coal mining are the most polluting life cycle stages

User's manual for levelized power generation cost using a microcomputer

International Nuclear Information System (INIS)

Fuller, L.C.

1984-08-01

Microcomputer programs for the estimation of levelized electrical power generation costs are described. Procedures for light-water reactor plants and coal-fired plants include capital investment cost, operation and maintenance cost, fuel cycle cost, nuclear decommissioning cost, and levelized total generation cost. Programs are written in Pascal and are run on an Apple II Plus microcomputer

Externality costs of the coal-fuel cycle: The case of Kusile Power Station

Directory of Open Access Journals (Sweden)

Nonophile P. Nkambule

2017-09-01

Full Text Available Coal-based electricity is an integral part of daily life in South Africa and globally. However, the use of coal for electricity generation carries a heavy cost for social and ecological systems that goes far beyond the price we pay for electricity. We developed a model based on a system dynamics approach for understanding the measurable and quantifiable coal-fuel cycle burdens and externality costs, over the lifespan of a supercritical coal-fired power station that is fitted with a flue-gas desulfurisation device (i.e. Kusile Power Station. The total coal-fuel cycle externality cost on both the environment and humans over Kusile's lifespan was estimated at ZAR1 449.9 billion to ZAR3 279 billion or 91c/kWh to 205c/kWh sent out (baseline: ZAR2 172.7 billion or 136c/kWh. Accounting for the life-cycle burdens and damages of coal-derived electricity conservatively, doubles to quadruples the price of electricity, making renewable energy sources such as wind and solar attractive alternatives. Significance: The use of coal for electricity generation carries a heavy cost for social and ecological systems that goes far beyond the price we pay for electricity. The estimation of social costs is particularly important to the electric sector because of non-differentiation of electricity prices produced from a variety of sources with potentially very dissimilar environmental and human health costs. Because all electricity generation technologies are associated with undesirable side effects in their fuelcycle and lifespan, comprehensive comparative analyses of life-cycle costs of all power generation technologies is indispensable to guide the development of future energy policies in South Africa.

Economics of power generation from imported biomass

International Nuclear Information System (INIS)

Lako, P.; Van Rooijen, S.N.M.

1998-02-01

Attention is paid to the economics of import of biomass to the Netherlands, and subsequent utilisation for power generation, as a means to reduce dependence on (imported) fossil fuels and to reduce CO2 emission. Import of wood to the extent of 40 PJ or more from Baltic and South American states seems to be readily achievable. Import of biomass has various advantages, not only for the European Union (reduced CO2 emissions) but also for the countries of origin (employment creation). However, possible disadvantages or risks should be taken into account. With that in mind, import of biomass from Baltic states seems very interesting, although it should be noted that in some of those countries the alternative of fuel-switching to biomass seems to be more cost-effective than import of biomass from those countries. Given the expected increase in inland biomass consumption in the Baltic countries and the potential substantial future demand for biomass in other Western European countries it is expected that the biomass supply from Baltic countries will not be sufficient to fulfill the demand. An early focus on import from other countries seems advisable. Several power generation options are available with short to medium term potential and long term potential. The margin between costs of biomass-fuelled power and of coal fired power will be smaller, due to substantial improvements in power generating efficiency and reductions of investment costs of options for power generation from biomass, notably Biomass Gasification Combined Cycle. 18 refs

BIOMASS GASIFICATION AND POWER GENERATION USING ADVANCED GAS TURBINE SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

David Liscinsky

2002-10-20

A multidisciplined team led by the United Technologies Research Center (UTRC) and consisting of Pratt & Whitney Power Systems (PWPS), the University of North Dakota Energy & Environmental Research Center (EERC), KraftWork Systems, Inc. (kWS), and the Connecticut Resource Recovery Authority (CRRA) has evaluated a variety of gasified biomass fuels, integrated into advanced gas turbine-based power systems. The team has concluded that a biomass integrated gasification combined-cycle (BIGCC) plant with an overall integrated system efficiency of 45% (HHV) at emission levels of less than half of New Source Performance Standards (NSPS) is technically and economically feasible. The higher process efficiency in itself reduces consumption of premium fuels currently used for power generation including those from foreign sources. In addition, the advanced gasification process can be used to generate fuels and chemicals, such as low-cost hydrogen and syngas for chemical synthesis, as well as baseload power. The conceptual design of the plant consists of an air-blown circulating fluidized-bed Advanced Transport Gasifier and a PWPS FT8 TwinPac{trademark} aeroderivative gas turbine operated in combined cycle to produce {approx}80 MWe. This system uses advanced technology commercial products in combination with components in advanced development or demonstration stages, thereby maximizing the opportunity for early implementation. The biofueled power system was found to have a levelized cost of electricity competitive with other new power system alternatives including larger scale natural gas combined cycles. The key elements are: (1) An Advanced Transport Gasifier (ATG) circulating fluid-bed gasifier having wide fuel flexibility and high gasification efficiency; (2) An FT8 TwinPac{trademark}-based combined cycle of approximately 80 MWe; (3) Sustainable biomass primary fuel source at low cost and potentially widespread availability-refuse-derived fuel (RDF); (4) An overall integrated

The development situation of biomass gasification power generation in China

International Nuclear Information System (INIS)

Zhou, Zhaoqiu; Yin, Xiuli; Xu, Jie; Ma, Longlong

2012-01-01

This work presents the development situation of biomass gasification power generation technology in China and analyzes the difficulty and challenge in the development process. For China, a large agricultural country with abundant biomass resources, the utilization of biomass gasification power generation technology is of special importance, because it can contribute to the electricity structure diversification under the present coal-dominant electricity structure, ameliorate the environmental impact, provide energy to electricity-scarce regions and solve the problems facing agriculture. Up to now, China has developed biomass gasification power generation plants of different types and scales, including simple gas engine-based power generation systems with capacity from several kW to 3 MW and integrated gasification combined cycle systems with capacity of more than 5 MW. In recent years, due to the rising cost of biomass material, transportation, manpower, etc., the final cost of biomass power generation has increased greatly, resulting in a serious challenge in the Chinese electricity market even under present preferential policy for biomass power price. However, biomass gasification power generation technology is generally in accord with the characteristics of biomass resources in China, has relatively good adaptability and viability, and so has good prospect in China in the future. - Highlights: ► Biomass gasification power generation of 2 kW–2 MW has wide utilization in China. ► 5.5 MW biomass IGCC demonstration plant has maximum power efficiency of up to 30%. ► Biomass power generation is facing a serious challenge due to biomass cost increase.

Quantity, Quality, and Availability of Waste Heat from United States Thermal Power Generation.

Science.gov (United States)

Gingerich, Daniel B; Mauter, Meagan S

2015-07-21

Secondary application of unconverted heat produced during electric power generation has the potential to improve the life-cycle fuel efficiency of the electric power industry and the sectors it serves. This work quantifies the residual heat (also known as waste heat) generated by U.S. thermal power plants and assesses the intermittency and transport issues that must be considered when planning to utilize this heat. Combining Energy Information Administration plant-level data with literature-reported process efficiency data, we develop estimates of the unconverted heat flux from individual U.S. thermal power plants in 2012. Together these power plants discharged an estimated 18.9 billion GJ(th) of residual heat in 2012, 4% of which was discharged at temperatures greater than 90 °C. We also characterize the temperature, spatial distribution, and temporal availability of this residual heat at the plant level and model the implications for the technical and economic feasibility of its end use. Increased implementation of flue gas desulfurization technologies at coal-fired facilities and the higher quality heat generated in the exhaust of natural gas fuel cycles are expected to increase the availability of residual heat generated by 10.6% in 2040.

A Pseudo Fractional-N Clock Generator with 50% Duty Cycle Output

Science.gov (United States)

Yang, Wei-Bin; Lo, Yu-Lung; Chao, Ting-Sheng

A proposed pseudo fractional-N clock generator with 50% duty cycle output is presented by using the pseudo fractional-N controller for SoC chips and the dynamic frequency scaling applications. The different clock frequencies can be generated with the particular phase combinations of a four-stage voltage-controlled oscillator (VCO). It has been fabricated in a 0.13µm CMOS technology, and work with a supply voltage of 1.2V. According to measured results, the frequency range of the proposed pseudo fractional-N clock generator is from 71.4MHz to 1GHz and the peak-to-peak jitter is less than 5% of the output period. Duty cycle error rates of the output clock frequencies are from 0.8% to 2% and the measured power dissipation of the pseudo fractional-N controller is 146µW at 304MHz.

Supercritical Water Reactor Cycle for Medium Power Applications

International Nuclear Information System (INIS)

BD Middleton; J Buongiorno

2007-01-01

and pipes were modeled with realistic assumptions using the PEACE module of Thermoflex. A three-dimensional layout of the plant was also generated with the SolidEdge software. The results of the engineering design are as follows: (i) The cycle achieves a net thermal efficiency of 24.13% with 350/460 C reactor inlet/outlet temperatures, ∼250 bar reactor pressure and 0.75 bar condenser pressure. The steam quality at the turbine outlet is 90% and the total electric consumption of the pumps is about 2500 kWe at nominal conditions. (ii) The overall size of the plant is attractively compact and can be further reduced if a printed-circuit-heat-exchanger (vs shell-and-tube) design is used for the feedwater heater, which is currently the largest component by far. Finally, an analysis of the plant performance at off-nominal conditions has revealed good robustness of the design in handling large changes of thermal power and seawater temperature

User's manual for levelized power generation cost using an IBM PC

International Nuclear Information System (INIS)

Fuller, L.C.

1985-06-01

Programs for the estimation of levelized electric power generation costs using the BASIC interpreter on an IBM PC are described. Procedures for light-water reactor plants and coal-fired plants include capital investment cost, operation and maintenance cost, fuel cycle cost, nuclear decommissioning cost, and levelized total generation cost

Life cycle cost analysis of wind power considering stochastic uncertainties

International Nuclear Information System (INIS)

Li, Chiao-Ting; Peng, Huei; Sun, Jing

2014-01-01

This paper presents a long-term cost analysis of wind power and compares its competitiveness to non-renewable generating technologies. The analysis considers several important attributes related to wind intermittency that are sometimes ignored in traditional generation planning or LCOE (levelized cost of energy) studies, including the need for more nameplate capacity due to intermittency, hourly fluctuations in wind outputs and cost for reserves. The competitiveness of wind power is assessed by evaluating four scenarios: 1) adding natural gas generating capacity to the power grid; 2) adding coal generating capacity to the power grid; 3) adding wind capacity to the power grid; and, 4) adding wind capacity and energy storage to the power grid where an energy storage device is used to cover wind intermittency. A case study in the state of Michigan is presented to demonstrate the use of the proposed methodology, in which a time horizon from 2010 to 2040 is considered. The results show that wind energy will still be more expensive than natural gas power plants in the next three decades, but will be cheaper than coal capacities if wind intermittency is mitigated. Furthermore, if the costs of carbon emissions and environmental externalities are considered, wind generation will be a competitive option for grid capacity expansion. - Highlights: • The competitiveness of wind power is analyzed via life cycle cost analysis. • Wind intermittency and reserve costs are explicitly considered in the analysis. • Results show that wind is still more expensive than natural gas power plants. • Wind can be cheaper than coal capacities if wind intermittency is mitigated. • Wind will be competitive if costs of carbon emissions are considered

Life Cycle Assessment of Coal-fired Power Production

Energy Technology Data Exchange (ETDEWEB)

Spath, P. L.; Mann, M. K.; Kerr, D. R.

1999-09-01

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).

On q-power cycles in cubic graphs

DEFF Research Database (Denmark)

Bensmail, Julien

2017-01-01

In the context of a conjecture of Erdos and Gyárfás, we consider, for any q ≥ 2, the existence of q-power cycles (i.e. with length a power of q) in cubic graphs. We exhibit constructions showing that, for every q ≥ 3, there exist arbitrarily large cubic graphs with no q-power cycles. Concerning...... the remaining case q = 2 (which corresponds to the conjecture of Erdos and Gyárfás), we show that there exist arbitrarily large cubic graphs whose only 2-power cycles have length 4 only, or 8 only....

Estimation, comparison, and evaluation of advanced fission power reactor generation costs

International Nuclear Information System (INIS)

Waddell, J.D.

1977-01-01

The study compares the high-temperature gas-cooled reactor (HTGR), the gas-cooled fast reactor (GCFR), the molten-salt breeder reactor (MSBR), the light water breeder reactor (LWBR), and the heavy water reactor (HWR) with proposed light water reactors (LWR) and liquid-metal fast breeder reactors (LMFBR). The relative electrical generation costs, including the effects of the introduction of advanced reactor fuel cycles into the U.S. nuclear power economy, were projected through the year 2030. The study utilized the NEEDS computer code which is a simulation of the U.S. nuclear power economy. The future potential electrical generation costs and cumulative consumption of uranium ore were developed using characterizations of the advanced systems. The reactor-fuel cycle characterizations were developed from literature reviews and personal discussions with the proponents of the various systems. The study developed a ranking of the concepts based on generation costs and uranium consumption

Outlook of nuclear power generation and international situation

Energy Technology Data Exchange (ETDEWEB)

Ekulund, S [International Atomic Energy Agency, Vienna (Austria)

1978-01-01

Nuclear power generation is advancing at rapid rate over the world, without any major accident. For the base load of electric power, when choice is made between nuclear energy and petroleum, Nuclear energy has larger economic advantages over petroleum as compared with the days before the oil crisis. The costs of its fuel and fuel cycle technology are reasonable. However, nuclear power generation currently has a number of problems. What causes this uncertainty is not technological, but political, i.e. governmental policy changes, and this is based on the apprehension about nuclear proliferation. What is necessary is to strengthen the existing international framework of nuclear nonproliferation. In this respect, IAEA through comprehensive safeguards will make contributions largely to reduction of the political uncertainty. It is important that the new initiatives toward international nuclear cooperation should eliminate the current trends of restraint and denial.

Design of a partial inter-tube lancing system actuated by hydraulic power for type F model steam generator in nuclear power plant

International Nuclear Information System (INIS)

Kim, S. T.; Jeong, W. T.

2008-01-01

The sludge grown up in steam generators of nuclear power plants shortens the life-cycle of steam generators and reduces the output of power plants. So KHNP(Korea Hydro and Nuclear Power), the only nuclear power utility in Korea, removes it periodically using a steam generator lancing system during the outage of plants for an overhaul. KEPRI(Korea Electric Power Research Institute) has developed lancing systems with high pressured water nozzle for steam generators of nuclear power plants since 2001. In this paper, the design of a partial inter-tube lancing system for model F type steam generators will be described. The system is actuated without a DC motor inner steam generators because the motors in a steam generator make a trouble from high intensity of radioactivity as a break down

Conceptual study of nuclear power generation facilities life-cycle support versatile engineering database. Procedure of development and consideration of fundamental functions

International Nuclear Information System (INIS)

Endo, Hidetoshi

2009-05-01

International Atomic Energy Agency (IAEA) stands out the activity of the knowledge management of nuclear safety and the movement to introduce the idea of the life cycle management into the quality control of maintenance of the nuclear power generation facilities to assure the knowledge preservation and to succeed the technology of facilities. Japan Atomic Energy Agency (JAEA) also has such activities as the knowledge preservation of research and development, and related information. The facilities' performance reliability can be easily checked with the technology of data processing in the general industry and the results of the knowledge repository, transmitting technology and knowledge management by referring to the information and knowledge if the information and knowledge at each step of the life-cycle of facilities can be built. This report shows the strategy of the construction of the engineering database to support the life cycle of facilities and the basic function of the management system. (author)

Electrofishing power requirements in relation to duty cycle

Science.gov (United States)

Miranda, L.E.; Dolan, C.R.

2004-01-01

Under controlled laboratory conditions we measured the electrical peak power required to immobilize (i.e., narcotize or tetanize) fish of various species and sizes with duty cycles (i.e., percentage of time a field is energized) ranging from 1.5% to 100%. Electrofishing effectiveness was closely associated with duty cycle. Duty cycles of 10-50% required the least peak power to immobilize fish; peak power requirements increased gradually above 50% duty cycle and sharply below 10%. Small duty cycles can increase field strength by making possible higher instantaneous peak voltages that allow the threshold power needed to immobilize fish to radiate farther away from the electrodes. Therefore, operating within the 10-50% range of duty cycles would allow a larger radius of immobilization action than operating with higher duty cycles. This 10-50% range of duty cycles also coincided with some of the highest margins of difference between the electrical power required to narcotize and that required to tetanize fish. This observation is worthy of note because proper use of duty cycle could help reduce the mortality associated with tetany documented by some authors. Although electrofishing with intermediate duty cycles can potentially increase effectiveness of electrofishing, our results suggest that immobilization response is not fully accounted for by duty cycle because of a potential interaction between pulse frequency and duration that requires further investigation.

Power generation by nuclear power plants

International Nuclear Information System (INIS)

Bacher, P.

2004-01-01

Nuclear power plays an important role in the world, European (33%) and French (75%) power generation. This article aims at presenting in a synthetic way the main reactor types with their respective advantages with respect to the objectives foreseen (power generation, resources valorization, waste management). It makes a fast review of 50 years of nuclear development, thanks to which the nuclear industry has become one of the safest and less environmentally harmful industry which allows to produce low cost electricity: 1 - simplified description of a nuclear power generation plant: nuclear reactor, heat transfer system, power generation system, interface with the power distribution grid; 2 - first historical developments of nuclear power; 3 - industrial development and experience feedback (1965-1995): water reactors (PWR, BWR, Candu), RBMK, fast neutron reactors, high temperature demonstration reactors, costs of industrial reactors; 4 - service life of nuclear power plants and replacement: technical, regulatory and economical lifetime, problems linked with the replacement; 5 - conclusion. (J.S.)

Economic analysis of extended cycles in the Laguna Verde nuclear power plant

International Nuclear Information System (INIS)

Hernandez N, H.; Hernandez M, J.L.; Francois L, J.L.

2004-01-01

The present work presents a preliminary analysis of economic type of extended cycles of operation of the Unit One in the Laguna Verde nuclear power plant. It is analysed an equilibrium cycle of 18 months firstly, with base to the Plan of Use of Energy of the Federal Commission of Electricity, being evaluated the cost of the energy until the end of the useful life of the plant. Later on an alternative recharge scenario is presented with base to an equilibrium cycle of 24 months, implemented to the beginning of the cycle 11, without considering transition cycles. It is added in both cycles the cost of the substitution energy, considering the unitary cost of the fuel of a dual thermoelectric power station of 350 M We and evaluating in each operation cycle, in both scenarios, the value of the substitution energy. The results show that a reduction of the days of recharge in the cycle of 24 months could make this option but favorable economically. The duration of the period of recharge rebounds in considerable grade in the cost of energy generation for concept of fuel. (Author)

Present state and prospect of nuclear power generation

International Nuclear Information System (INIS)

Fukushima, Akira

1980-01-01

Energy resources are scarce in Japan, therefore Japan depends heavily on imported petroleum. However, the international situation of petroleum became more unstable recently, and the promotion of the development and utilization of nuclear power generation was agreed upon in the summit meeting and the IEA. In order to achieve the stable growth of economy and improve the national welfare in Japan, it is urgent subject to accelerate the development of nuclear power generation. Japan depends the nuclear fuel also on import, but the stable supply is assured by the contract of long term purchase. It is not necessary to replace nuclear fuel usually for three years, and the transport and storage of nuclear fuel are easy because the quantity is not very large. By establishing the independent nuclear fuel cycle in Japan, it is possible to give the character similar to domestically produced energy to nuclear fuel. Moreover, uranium resources can be effectively utilized by the development of nuclear reactors of new types, such as FBRs. The cost of generating 1 kWh of electricity was about 8 yen in case of nuclear power and 15 yen in petroleum thermal power as of January, 1980. 21 nuclear power plants of about 15 million kW capacity are in operation in Japan, and about 30 million kW will be installed by 1985. The measures to promote the development of nuclear power generation are discussed. (Kako, I.)

Some consideration on nuclear power development. Topics aroused by U.S. proposed 'Generation IV Nuclear Power System

International Nuclear Information System (INIS)

Wang Chuanying; Chen Shiqi

2001-01-01

U.S. proposed 'Generation IV Nuclear Power System' concept. Its origin and proposed goals for it are analyzed; goals are compared with requirements of URD. In particular, discussed issues on nuclear fuel cycle and Non-proliferation. A well-considered nuclear power development plan, paying close attention to international trend and considering comprehensively domestic situation, is expected

How new power generation technologies will affect the development of independent power

International Nuclear Information System (INIS)

Bhan, S.K.

1999-01-01

The deregulation of electricity markets in North America have made it possible for independent power producers to generate electricity. This presentation focused on the different factors that should be considered when developing cogeneration projects, including their inherent environmental benefits. Cogeneration is the combined production of thermal energy and electricity. The main requirement for cogeneration is that there should be a market for both electricity as well as thermal energy. This means that any large institutions where steam or hot water is used for heating can qualify for cogeneration of electricity. The development of cogeneration projects has been encouraged by recent advances in technology in gas turbines, micro-turbines, coal-fired generation and fuel cells. Future technologies will include improved circulating fluidized bed boilers, low NO x burners, and selective catalytic reactors. The newest technologies claim to achieve simple cycle efficiency approaching 40 per cent. In the combined cycle, efficiencies of 60 per cent can be achieved, while 80 per cent efficiency can be achieved in cogeneration. This paper described various cogeneration options including: (1) gas turbines with unfired heat recovery steam generators (HRSG), (2) gas turbines with fired HRSG, (3) combined cycle plants, and (4) reciprocating engines. The efficiency of cogeneration makes it a viable option for reducing greenhouse gases (GHGs). 5 tabs

Thermoelectric power generator for variable thermal power source

Science.gov (United States)

Bell, Lon E; Crane, Douglas Todd

2015-04-14

Traditional power generation systems using thermoelectric power generators are designed to operate most efficiently for a single operating condition. The present invention provides a power generation system in which the characteristics of the thermoelectrics, the flow of the thermal power, and the operational characteristics of the power generator are monitored and controlled such that higher operation efficiencies and/or higher output powers can be maintained with variably thermal power input. Such a system is particularly beneficial in variable thermal power source systems, such as recovering power from the waste heat generated in the exhaust of combustion engines.

Energy, Exergy and Performance Analysis of Small-Scale Organic Rankine Cycle Systems for Electrical Power Generation Applicable in Rural Areas of Developing Countries

Directory of Open Access Journals (Sweden)

Suresh Baral

2015-01-01

Full Text Available This paper introduces the concept of installing a small-scale organic Rankine cycle system for the generation of electricity in remote areas of developing countries. The Organic Rankine Cycle Systems (ORC system uses a commercial magnetically-coupled scroll expander, plate type heat exchangers and plunger type working fluid feed pump. The heat source for the ORC system can be solar energy. A series of laboratory tests were conducted to confirm the cycle efficiency and expander power output of the system. Using the actual system data, the exergy destruction on the system components and exergy efficiency were assessed. Furthermore, the results of the variations of system energy and exergy efficiencies with different operating parameters, such as the evaporating and condensing pressures, degree of superheating, dead state temperature, expander inlet temperature and pressure ratio were illustrated. The system exhibited acceptable operational characteristics with good performance under a wide range of conditions. A heat source temperature of 121 °C is expected to deliver a power output of approximately 1.4 kW. In addition, the system cost analysis and financing mechanisms for the installation of the ORC system were discussed.

Power generation technologies

CERN Document Server

Breeze, Paul

2014-01-01

The new edition of Power Generation Technologies is a concise and readable guide that provides an introduction to the full spectrum of currently available power generation options, from traditional fossil fuels and the better established alternatives such as wind and solar power, to emerging renewables such as biomass and geothermal energy. Technology solutions such as combined heat and power and distributed generation are also explored. However, this book is more than just an account of the technologies - for each method the author explores the economic and environmental costs and risk factor

Alternative ORC bottoming cycles FOR combined cycle power plants

International Nuclear Information System (INIS)

Chacartegui, R.; Sanchez, D.; Munoz, J.M.; Sanchez, T.

2009-01-01

In this work, low temperature Organic Rankine Cycles are studied as bottoming cycle in medium and large scale combined cycle power plants. The analysis aims to show the interest of using these alternative cycles with high efficiency heavy duty gas turbines, for example recuperative gas turbines with lower gas turbine exhaust temperatures than in conventional combined cycle gas turbines. The following organic fluids have been considered: R113, R245, isobutene, toluene, cyclohexane and isopentane. Competitive results have been obtained for toluene and cyclohexane ORC combined cycles, with reasonably high global efficiencies. The paper is structured in four main parts. A review of combined cycle and ORC cycle technologies is presented, followed by a thermodynamic analysis of combined cycles with commercial gas turbines and ORC low temperature bottoming cycles. Then, a parametric optimization of an ORC combined cycle plant is performed in order to achieve a better integration between these two technologies. Finally, some economic considerations related to the use of ORC in combined cycles are discussed.

The Application of Supercritical CO{sub 2} Power Cycle to Various Nuclear Systems

Energy Technology Data Exchange (ETDEWEB)

Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

2015-10-15

The main reason why the S-CO{sub 2} Brayton cycle has these advantages is that the compressor operates near the critical point of CO{sub 2} (30.98 .deg. C, 7.38MPa) to reduce the compression work significantly compared to the other Brayton cycles. In this paper, various applications of supercritical CO{sub 2} power cycle to nuclear systems will be presented and summarized. The S-CO{sub 2} cycle can achieve relatively high efficiency within the mild turbine inlet temperature range (450 - 850 .deg. C) compared with other power conversion systems. The main benefit of the S-CO{sub 2} cycle is the small size of the overall system and its application includes not only the next generation nuclear reactors but also conventional water-cooled reactors too. Various layouts were compared and the recompression cycle shows the best efficiency. The layout is suitable for application to advanced nuclear reactor systems. To evaluate the S-CO{sub 2} cycle performance, various countries constructed and demonstrated S-CO{sub 2} integral system test loops and similar research works are ongoing in Korea as well. However, to evaluate the commercial S-CO{sub 2} power systems, development of a large scale (> 10 MW) prototype S-CO{sub 2} system is necessary.

Tackling investment challenges in power generation - in IEA countries

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-07-01

In most IEA countries a new investment cycle in power generation is looming. A window of opportunity now exists to push for a cleaner and more efficient generation portfolio that could transform the power sector and help to build a more sustainable infrastructure lasting over the next 40-50 years. What are the recent trends and prospects for investment in power generation? What are the main drivers and barriers? This book assesses these issues and gives special emphasis to the question of how uncertainties may affect investment decisions. Uncertainties on CO{sub 2} constraints, on power plant licensing, on acceptability of nuclear power, on local opposition to any new energy infrastructure, on government support for specific generation technologies and on government policies on energy efficiency are particularly disturbing. Market liberalisation can also be a key uncertainty, but this may be greatly reduced and deliver considerable benefits if liberalisation is implemented whole-heartedly and backed by on-going government commitment. Government action is urgently needed: to reduce regulatory uncertainty for investors, to establish effective competitive markets and to give firm policy directions in those areas where markets fall short, such as in taking environmental costs and security of supply into account.

Effect of pedaling rates and myosin heavy chain composition in the vastus lateralis muscle on the power generating capability during incremental cycling in humans.

Science.gov (United States)

Majerczak, J; Szkutnik, Z; Duda, K; Komorowska, M; Kolodziejski, L; Karasinski, J; Zoladz, J A

2008-01-01

In this study, we have determined power output reached at maximal oxygen uptake during incremental cycling exercise (P(I, max)) performed at low and at high pedaling rates in nineteen untrained men with various myosin heavy chain composition (MyHC) in the vastus lateralis muscle. On separate days, subjects performed two incremental exercise tests until exhaustion at 60 rev min(-1) and at 120 rev min(-1). In the studied group of subjects P(I, max) reached during cycling at 60 rev min(-1) was significantly higher (p=0.0001) than that at 120 rev min(-1) (287+/-29 vs. 215+/-42 W, respectively for 60 and 120 rev min(-1)). For further comparisons, two groups of subjects (n=6, each) were selected according to MyHC composition in the vastus lateralis muscle: group H with higher MyHC II content (56.8+/-2.79 %) and group L with lower MyHC II content in this muscle (28.6+/-5.8 %). P(I, max) reached during cycling performed at 60 rev min(-1) in group H was significantly lower than in group L (p=0.03). However, during cycling at 120 rev min(-1), there was no significant difference in P(I, max) reached by both groups of subjects (p=0.38). Moreover, oxygen uptake (VO(2)), blood hydrogen ion [H(+)], plasma lactate [La(-)] and ammonia [NH(3)] concentrations determined at the four highest power outputs completed during the incremental cycling performed at 60 as well as 120 rev min(-1), in the group H were significantly higher than in group L. We have concluded that during an incremental exercise performed at low pedaling rates the subjects with lower content of MyHC II in the vastus lateralis muscle possess greater power generating capabilities than the subjects with higher content of MyHC II. Surprisingly, at high pedaling rate, power generating capabilities in the subjects with higher MyHC II content in the vastus lateralis muscle did not differ from those found in the subjects with lower content of MyHC II in this muscle, despite higher blood [H(+)], [La(-)] and [NH(3

ECONOMICS AND FEASIBILITY OF RANKINE CYCLE IMPROVEMENTS FOR COAL FIRED POWER PLANTS

Energy Technology Data Exchange (ETDEWEB)

Richard E. Waryasz; Gregory N. Liljedahl

2004-09-08

study therefore determines the steam cycle parameters and combustion technology that would yield the lowest cost of electricity (COE) for the next generation of coal-fired steam power plants. The second part of the study (Repowering) explores the means of upgrading the efficiency and output of an older existing coal fired steam power plant. There are currently more than 1,400 coal-fired units in operation in the United States generating about 54 percent of the electricity consumed. Many of these are modern units are clean and efficient. Additionally, there are many older units in excellent condition and still in service that could benefit from this repowering technology. The study evaluates the technical feasibility, thermal performance, and economic viability of this repowering concept.

A study on the generation of radioactive corrosion product at PWR for extended fuel cycle

International Nuclear Information System (INIS)

Min Chul Song; Kun Jai Lee

2001-01-01

Current nuclear power plant operating practice is to extend the time between refueling from a 12 month operating cycle to an 18-24 month period. This current to longer fuel cycles has complicated the dilemma of finding optimum pH range for the primary coolant chemistry. The International Commission on Radiological Protection (ICRP) in ICRP publication No. 60 recommends optimization of operator radiation exposure (ORE) in nuclear power plants. CRUD formed in the plants is the major source of ORE and its transport mechanism is not understood. To analyze the generation of CRUD at the extended fuel cycle, the COTRAN code, which was developed at the Korea Advanced Institute of Science and Technology (KAIST), was used. It predicts that the activity of CRUD decreases as the pH of the coolant increases. For the same period of different fuel cycles, as the operating fuel cycle duration is increased, the generation of the CRUD increases. In this paper, enriched boric acid (40% enriched 10 B concentration) for reactivity control is adopted as the required chemical shim rather than natural boric acid. The effect of the enriched boric acid (EBA) is that the neutron absorption capability of the chemical shim is maintained while decreasing the required boron and lithium concentration in the reactor coolant system. By employing enriched boric acid, the amounts of CRUD generated are reduced, because the high pH-operating period is extended. From the waste generation point of view, more filters or ion exchangers to remove CRUD are required and the amounts of waste are increased at the extended fuel cycle. (author)

Integrated assessment of IGCC power generation technology with carbon capture and storage (CCS)

International Nuclear Information System (INIS)

Cormos, Calin-Cristian

2012-01-01

IGCC (Integrated Gasification Combined Cycle) is a power generation technology in which the solid feedstock is partially oxidized with oxygen and steam to produce syngas. In a conventional IGCC design without carbon capture, the syngas is purified for dust and hydrogen sulphide removal and then it is sent to a CCGT (Combined Cycle Gas Turbine) for power generation. CCS (Carbon capture and storage) technologies are expected to play a significant role in the coming decades for reducing the greenhouse gas emissions. IGCC is one of the power generation technologies having the highest potential to capture CO 2 with low penalties in term of plant energy efficiency, capital and operational costs. This paper investigates the most important techno-economic and environmental indicators (e.g. power output, ancillary consumption, energy efficiency, CW consumption, normalised mass and energy balances and plant construction materials, capital and O and M (operational and maintenance) costs, specific CO 2 emissions, cost of electricity, CO 2 removal and avoidance costs etc.) for IGCC with CCS. Coal-based IGCC cases produce around 400–450 MW net electricity with 90% carbon capture rate. Similar IGCC plants without CCS were presented as references. Future IGCC developments for energy vectors poly-generation were also presented. -- Highlights: ► Techno-economical evaluations of coal-based IGCC power generation with CCS. ► Model development for capital, O and M, CO 2 capture costs and cash flow estimations. ► Technical and economic investigations of key plant design characteristics. ► Evaluations of carbon capture options for IGCC power generation technology.

Power generation statistics

International Nuclear Information System (INIS)

Kangas, H.

2001-01-01

The frost in February increased the power demand in Finland significantly. The total power consumption in Finland during January-February 2001 was about 4% higher than a year before. In January 2001 the average temperature in Finland was only about - 4 deg C, which is nearly 2 degrees higher than in 2000 and about 6 degrees higher than long term average. Power demand in January was slightly less than 7.9 TWh, being about 0.5% less than in 2000. The power consumption in Finland during the past 12 months exceeded 79.3 TWh, which is less than 2% higher than during the previous 12 months. In February 2001 the average temperature was - 10 deg C, which was about 5 degrees lower than in February 2000. Because of this the power consumption in February 2001 increased by 5%. Power consumption in February was 7.5 TWh. The maximum hourly output of power plants in Finland was 13310 MW. Power consumption of Finnish households in February 2001 was about 10% higher than in February 2000, and in industry the increase was nearly zero. The utilization rate in forest industry in February 2001 decreased from the value of February 2000 by 5%, being only about 89%. The power consumption of the past 12 months (Feb. 2000 - Feb. 2001) was 79.6 TWh. Generation of hydroelectric power in Finland during January - February 2001 was 10% higher than a year before. The generation of hydroelectric power in Jan. - Feb. 2001 was nearly 2.7 TWh, corresponding to 17% of the power demand in Finland. The output of hydroelectric power in Finland during the past 12 months was 14.7 TWh. The increase from the previous 12 months was 17% corresponding to over 18% of the power demand in Finland. Wind power generation in Jan. - Feb. 2001 was exceeded slightly 10 GWh, while in 2000 the corresponding output was 20 GWh. The degree of utilization of Finnish nuclear power plants in Jan. - Feb. 2001 was high. The output of these plants was 3.8 TWh, being about 1% less than in Jan. - Feb. 2000. The main cause for the

Thermodynamic analysis of SCW NPP cycles with thermo-chemical co-generation of hydrogen

International Nuclear Information System (INIS)

Naidin, N.; Mokry, S.; Monichan, R.; Chophla, K.; Pioro, I.; Naterer, G.; Gabriel, K.

2009-01-01

Research activities are currently conducted worldwide to develop Generation IV nuclear reactor concepts with the objective of improving thermal efficiency and increasing economic competitiveness of Generation IV Nuclear Power Plants (NPPs) compared to modern thermal power plants. The Super-Critical Water-cooled Reactor (SCWR) concept is one of the six Generation IV options chosen for further investigation and development in several countries including Canada and Russia. Water-cooled reactors operating at subcritical pressures (10 - 16 MPa) have provided a significant amount of electricity production for the past 50 years. However, the thermal efficiency of the current NPPs is not very high (30 - 35%). As such, more competitive designs, with higher thermal efficiencies, which will be close to that of modern thermal power plants (45 - 50%), need to be developed and implemented. Super-Critical Water (SCW) NPPs will have much higher operating parameters compared to current NPPs (i.e., steam pressures of about 25 MPa and steam outlet temperatures up to 625 o C). Furthermore, SCWRs operating at higher temperatures can facilitate an economical co-generation of hydrogen through thermochemical cycles (particularly, the copper-chlorine cycle) or direct high-temperature electrolysis. The two SCW NPP cycles proposed by this paper are based on direct, regenerative, no-reheat and single-reheat configurations. As such, the main parameters and performance in terms of thermal efficiency of the SCW NPP concepts mentioned above are being analyzed. The cycles are generally comprised of: an SCWR, a SC turbine, one deaerator, ten feedwater heaters, and pumps. The SC turbine of the no-reheat cycle consists of one High-Pressure (HP) cylinder and two Low-Pressure (LP) cylinders. Alternatively, the SC turbine for the single-reheat cycle is comprised of one High-Pressure (HP) cylinder, one Intermediate-Pressure (IP) cylinder and two Low-Pressure (LP) cylinders. Since the single-reheat option

Modern combined cycle power plant utilizing the GT11N2

International Nuclear Information System (INIS)

Goodwin, J.C.

1992-01-01

The requirement imposed on modern power plants are increasingly demanding. The limits of: efficiency; environmental sensitivity; reliability and availability; are constantly being pushed. Today's state of the art combined cycle power plants are positioned well to meet these challenges. This paper reports that these objectives can be achieved through the selection of the proper gas turbine generator in an optimized cycle concept. A balanced approach to the plant design is required. It must not sacrifice any one of these requirements, in order to achieve the others. They achieve their fullest potential when firing a clean fuel, natural gas. However, fuel oil, both light (No. 2) and heavy (No. 6), can be utilized but some efficiency and environmental impact will have to be sacrificed

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

International Nuclear Information System (INIS)

Lee, Y.E.

2005-01-01

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.)

Evaluation of power block arrangements for 100MW scale concentrated solar thermal power generation using top-down design

Science.gov (United States)

Post, Alexander; Beath, Andrew; Sauret, Emilie; Persky, Rodney

2017-06-01

Concentrated solar thermal power generation poses a unique situation for power block selection, in which a capital intensive heat source is subject to daily and seasonal fluctuations in intensity. In this study, a method is developed to easily evaluate the favourability of different power blocks for converting the heat supplied by a concentrated solar thermal plant into power at the 100MWe scale based on several key parameters. The method is then applied to a range of commercially available power cycles that operate over different temperatures and efficiencies, and with differing capital costs, each with performance and economic parameters selected to be typical of their technology type, as reported in literature. Using this method, the power cycle is identified among those examined that is most likely to result in a minimum levelised cost of energy of a solar thermal plant.

Cheaper power generation from surplus steam generating capacities

International Nuclear Information System (INIS)

Gupta, K.

1996-01-01

Prior to independence most industries had their own captive power generation. Steam was generated in own medium/low pressure boilers and passed through extraction condensing turbines for power generation. Extraction steam was used for process. With cheaper power made available in Nehru era by undertaking large hydro power schemes, captive power generation in industries was almost abandoned except in sugar and large paper factories, which were high consumers of steam. (author)

Life-cycle assessment for power generation from wood fuels and wood wastes; Oekobilanz fuer die Stromerzeugung aus Holzbrennstoffen und Altholz

Energy Technology Data Exchange (ETDEWEB)

Jungbluth, N.; Frischknecht, R.; Faist, M.

2002-07-01

This reworked final report for the Swiss Federal Office of Energy (SFOE) presents the results of life-cycle assessments made of four wood-fired systems with the goal of analysing the possibilities of labelling such plants with the Swiss eco-label 'Naturemade Star'. In addition to these case studies, three standard technologies were modelled, whereby in two of the models different waste gas filtering methods were considered. In the third model, electricity is produced from waste wood and features an advanced waste gas treatment system. The report describes the various plants and draws up eco-balances for them. Pollution emissions, such as dust, oxides of nitrogen and sulphur dioxide, are discussed and plant operation and assessment are looked at. Certification to 'Naturemade Star' standards is checked out for the case-study plant examples and for the standard plant proposed. A further eco-balance is drawn up for wood-fired power generation with impact allocated to heat and power generation based on exergy content. An appendix provides details on the physical parameters of wood and on the methods used for impact assessment.

Corrosion products in power generating systems

International Nuclear Information System (INIS)

Lister, D.H.

1980-06-01

The important mechanisms of corrosion and corrosion product movement and fouling in the heat transport systems of thermal electric generating stations are reviewed. Oil- and coal-fired boilers are considered, along with nuclear power systems - both direct and indirect cycle. Thus, the fireside and waterside in conventional plants, and the primary coolant and steam-raising circuits in water-cooled reactors, are discussed. Corrosion products in organic- and liquid-metal-cooled reactors also are shown to cause problems if not controlled, while their beneficial effects on the cooling water side of condensers are described. (auth)

Life cycle energy use and GHG emission assessment of coal-based SNG and power cogeneration technology in China

International Nuclear Information System (INIS)

Li, Sheng; Gao, Lin; Jin, Hongguang

2016-01-01

Highlights: • Life cycle energy use and GHG emissions are assessed for SNG and power cogeneration. • A model based on a Chinese domestic database is developed for evaluation. • Cogeneration shows lower GHG emissions than coal-power pathway. • Cogeneration has lower life cycle energy use than supercritical coal-power pathway. • Cogeneration is a good option to implement China’s clean coal technologies. - Abstract: Life cycle energy use and GHG emissions are assessed for coal-based synthetic natural gas (SNG) and power cogeneration/polygenereation (PG) technology and its competitive alternatives. Four main SNG applications are considered, including electricity generation, steam production, SNG vehicle and battery electric vehicle (BEV). Analyses show that if SNG is produced from a single product plant, the lower limits of its life cycle energy use and GHG emissions can be comparable to the average levels of coal-power and coal-BEV pathways, but are still higher than supercritical and ultra supercritical (USC) coal-power and coal-BEV pathways. If SNG is coproduced from a PG plant, when it is used for power generation, steam production, and driving BEV car, the life cycle energy uses for PG based pathways are typically lower than supercritical coal-power pathways, but are still 1.6–2.4% higher than USC coal-power pathways, and the average life cycle GHG emissions are lower than those of all coal-power pathways including USC units. If SNG is used to drive vehicle car, the life cycle energy use and GHG emissions of PG-SNGV-power pathway are both much higher than all combined coal-BEV and coal-power pathways, due to much higher energy consumption in a SNG driven car than in a BEV car. The coal-based SNG and power cogeneration technology shows comparable or better energy and environmental performances when compared to other coal-based alternatives, and is a good option to implement China’s clean coal technologies.

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.

Electricity, nuclear power and fuel cycle in OECD countries

International Nuclear Information System (INIS)

1988-01-01

A questionnaire on Electricity Generation, Nuclear Power and Fuel Cycle Data is distributed annually to OECD Member Countries. In the questionnaire of January 1988, countries were asked to provide data for 1986 and 1987 and most likely projections up to the year 2005. The replies to the questionnaire (or estimates for unavailable data) are presented in this Booklet. Data for 1987 are provisional for several countries. The data on electricity generation and electric capacity are presented to the year 2005, and the data on fuel cycle services to the year 2000. The Addendum contains an analysis of the present and past projections for installed nuclear capacity to 2000. It shows the total capacity of those plants connected to the grid, under construction and firmly planned to be in operation in 2000 as 282 GWe. The new projection of 300 GWe is above this estimate, indicating that some countries are considering further expansion of their nuclear capacities within this time-frame [fr

Research report for fiscal 1998. Basic research for promoting joint implementation, etc. (conversion of old coal-fired thermoelectric power plants in Poland into combined cycle plants); 1998 nendo chosa hokokusho. Poland sekitan karyoku hatsudensho (kyushiki) combined cycle eno tenkan

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

A project is discussed for modernization for energy efficiency enhancement and greenhouse gas reduction. The most effective way to reduce greenhouse gas in Poland is to totally replace the existing coal-fired power plants with natural gas combined cycle plants. Under this project, however, natural gas-fired power generation and integrated coal/brown coal gasification combined cycle power generation are both subjected to study. This is because the power plant modernization project is closely related to the fate of coal/brown coal industries which constitute the important industrial department of Poland. As for the earning rate of the project in case of natural gas-fired combined cycle power generation, the rate will be 13.2% even at the Kaweczyn station which is the highest in earning rate, and this fails to satisfy the project conditions. If integrated coal/brown gasification combined cycle power generation is chosen, the rate will be still lower. When the cost for greenhouse gas reduction is taken up, the Konin station exhibits the lowest of 9 dollars/tCO2, and the others 15-17 dollars/tCO2. When coal gas combined cycle is employed, the cost will be 3-4 times higher. (NEDO)

Scale Resistant Heat Exchanger for Low Temperature Geothermal Binary Cycle Power Plant

Energy Technology Data Exchange (ETDEWEB)

Hays, Lance G. [Energent Corporation, Santa Ana, CA (United States)

2014-11-18

Phase 1 of the investigation of improvements to low temperature geothermal power systems was completed. The improvements considered were reduction of scaling in heat exchangers and a hermetic turbine generator (eliminating seals, seal system, gearbox, and lube oil system). A scaling test system with several experiments was designed and operated at Coso geothermal resource with brine having a high scaling potential. Several methods were investigated at the brine temperature of 235 ºF. One method, circulation of abradable balls through the brine passages, was found to substantially reduce scale deposits. The test heat exchanger was operated with brine outlet temperatures as low as 125 ºF, which enables increased heat input available to power conversion systems. For advanced low temperature cycles, such as the Variable Phase Cycle (VPC) or Kalina Cycle, the lower brine temperature will result in a 20-30% increase in power production from low temperature resources. A preliminary design of an abradable ball system (ABS) was done for the heat exchanger of the 1 megawatt VPC system at Coso resource. The ABS will be installed and demonstrated in Phase 2 of this project, increasing the power production above that possible with the present 175 ºF brine outlet limit. A hermetic turbine generator (TGH) was designed and manufacturing drawings produced. This unit will use the working fluid (R134a) to lubricate the bearings and cool the generator. The 200 kW turbine directly drives the generator, eliminating a gearbox and lube oil system. Elimination of external seals eliminates the potential of leakage of the refrigerant or hydrocarbon working fluids, resulting in environmental improvement. A similar design has been demonstrated by Energent in an ORC waste heat recovery system. The existing VPC power plant at Coso was modified to enable the “piggyback” demonstration of the TGH. The existing heat exchanger, pumps, and condenser will be operated to provide the required

Rotary-Atomizer Electric Power Generator

Science.gov (United States)

Nguyen, Trieu; Tran, Tuan; de Boer, Hans; van den Berg, Albert; Eijkel, Jan C. T.

2015-03-01

We report experimental and theoretical results on a ballistic energy-conversion method based on a rotary atomizer working with a droplet acceleration-deceleration cycle. In a rotary atomizer, liquid is fed onto the center of a rotating flat surface, where it spreads out under the action of the centrifugal force and creates "atomized" droplets at its edge. The advantage of using a rotary atomizer is that the centrifugal force exerted on the fluid on a smooth, large surface is not only a robust form of acceleration, as it avoids clogging, but also easily allows high throughput, and produces high electrical power. We successfully demonstrate an output power of 4.9 mW and a high voltage up to 3120 V. At present, the efficiency of the system is still low (0.14%). However, the conversion mechanism of the system is fully interpreted in this paper, permitting a conceptual understanding of system operation and providing a roadmap for system optimization. This observation will open up a road for building power-generation systems in the near future.

Technical Feasibility Study of Thermal Energy Storage Integration into the Conventional Power Plant Cycle

Directory of Open Access Journals (Sweden)

Jacek D. Wojcik

2017-02-01

Full Text Available The current load balance in the grid is managed mainly through peaking fossil-fuelled power plants that respond passively to the load changes. Intermittency, which comes from renewable energy sources, imposes additional requirements for even more flexible and faster responses from conventional power plants. A major challenge is to keep conventional generation running closest to the design condition with higher load factors and to avoid switching off periods if possible. Thermal energy storage (TES integration into the power plant process cycle is considered as a possible solution for this issue. In this article, a technical feasibility study of TES integration into a 375-MW subcritical oil-fired conventional power plant is presented. Retrofitting is considered in order to avoid major changes in the power plant process cycle. The concept is tested based on the complete power plant model implemented in the ProTRAX software environment. Steam and water parameters are assessed for different TES integration scenarios as a function of the plant load level. The best candidate points for heat extraction in the TES charging and discharging processes are evaluated. The results demonstrate that the integration of TES with power plant cycle is feasible and provide a provisional guidance for the design of the TES system that will result in the minimal influence on the power plant cycle.

Off-design performance analysis of a solar-powered organic Rankine cycle

International Nuclear Information System (INIS)

Wang, Jiangfeng; Yan, Zhequan; Zhao, Pan; Dai, Yiping

2014-01-01

Highlights: • Solar-powered organic Rankine cycle with CPC and thermal storage unit is studied. • Off-design performances encountering the changes of key parameters are examined. • Off-design performance is analyzed over a whole day and in different months. - Abstract: Performance evaluation of a thermodynamic system under off-design conditions is very important for reliable and cost-effective operation. In this study, an off-design model of an organic Rankine cycle driven by solar energy is established with compound parabolic collector (CPC) to collect the solar radiation and thermal storage unit to achieve the continuous operation of the overall system. The system off-design behavior is examined under the change in environment temperature, as well as thermal oil mass flow rates of vapor generator and CPC. In addition, the off-design performance of the system is analyzed over a whole day and in different months. The results indicate that a decrease in environment temperature, or the increases in thermal oil mass flow rates of vapor generator and CPC could improve the off-design performance. The system obtains the maximum average exergy efficiency in December and the maximum net power output in June or in September. Both the net power output and the average exergy efficiency reach minimum values in August

A life-cycle based decision-making framework for electricity generation system planning

Energy Technology Data Exchange (ETDEWEB)

Norrie, S.J.; Fang, L. [Ryerson Polytechnic Univ., Toronto, ON (Canada). Environmental Applied Science and Management Graduate Program

2006-07-01

This paper proposed a framework for the consideration of multiple objectives in the long-term planning of electricity generation systems. The framework was comprised of 3 components: (1) information based on life-cycle inventories of electricity generation technologies; (2) a set of alternative scenarios to be evaluated and ranked using the framework; and (3) stakeholder values for decision objectives. Scenarios were developed to represent a set of future conditions, and values were derived through the use of questionnaires. Planning for electricity generation in Ontario was selected as a test case for the DM framework. Three scenarios were presented: (1) a business as usual scenario characterized by large, central power plants; (2) a mix of central power plants, distributed generation, and advanced conventional fuel technologies; and (3) small-scale distributed and renewable energy sources and aggressive demand-side management. The life-cycle based information from the scenario evaluation was used to estimate the performance of each scenario on the established decision criteria. Results showed that scenario 3 was the closest to achieving the fundamental objectives according to the decision criteria. It was concluded that the DM framework showed that the use of holistic environmental information and preferential information for multiple objectives can be integrated into a framework that openly and consistently evaluates a set of alternative scenarios. 31 refs., 7 tabs., 4 figs.

Finite time thermodynamics of power and refrigeration cycles

CERN Document Server

Kaushik, Shubhash C; Kumar, Pramod

2017-01-01

This book addresses the concept and applications of Finite Time Thermodynamics to various thermal energy conversion systems including heat engines, heat pumps, and refrigeration and air-conditioning systems. The book is the first of its kind, presenting detailed analytical formulations for the design and optimisation of various power producing and cooling cycles including but not limited to: • Vapour power cycles • Gas power cycles • Vapour compression cycles • Vapour absorption cycles • Rankine cycle coupled refrigeration systems Further, the book addresses the thermoeconomic analysis for the optimisation of thermal cycles, an important field of study in the present age and which is characterised by multi-objective optimization regarding energy, ecology, the environment and economics. Lastly, the book provides the readers with key techniques associated with Finite Time Thermodynamics, allowing them to understand the relevance of irreversibilitie s associated with real processes and the scientific r...

Optimal paths of piston motion of irreversible diesel cycle for minimum entropy generation

Directory of Open Access Journals (Sweden)

Ge Yanlin

2011-01-01

Full Text Available A Diesel cycle heat engine with internal and external irreversibility’s of heat transfer and friction, in which the finite rate of combustion is considered and the heat transfer between the working fluid and the environment obeys Newton’s heat transfer law [q≈ Δ(T], is studied in this paper. Optimal piston motion trajectories for minimizing entropy generation per cycle are derived for the fixed total cycle time and fuel consumed per cycle. Optimal control theory is applied to determine the optimal piston motion trajectories for the cases of with piston acceleration constraint on each stroke and the optimal distribution of the total cycle time among the strokes. The optimal piston motion with acceleration constraint for each stroke consists of three segments, including initial maximum acceleration and final maximum deceleration boundary segments, respectively. Numerical examples for optimal configurations are provided, and the results obtained are compared with those obtained when maximizing the work output with Newton’s heat transfer law. The results also show that optimizing the piston motion trajectories could reduce engine entropy generation by more than 20%. This is primarily due to the decrease in entropy generation caused by heat transfer loss on the initial portion of the power stroke.

Life cycle GHG assessment of fossil fuel power plants with carbon capture and storage

International Nuclear Information System (INIS)

Odeh, Naser A.; Cockerill, Timothy T.

2008-01-01

The evaluation of life cycle greenhouse gas emissions from power generation with carbon capture and storage (CCS) is a critical factor in energy and policy analysis. The current paper examines life cycle emissions from three types of fossil-fuel-based power plants, namely supercritical pulverized coal (super-PC), natural gas combined cycle (NGCC) and integrated gasification combined cycle (IGCC), with and without CCS. Results show that, for a 90% CO 2 capture efficiency, life cycle GHG emissions are reduced by 75-84% depending on what technology is used. With GHG emissions less than 170 g/kWh, IGCC technology is found to be favorable to NGCC with CCS. Sensitivity analysis reveals that, for coal power plants, varying the CO 2 capture efficiency and the coal transport distance has a more pronounced effect on life cycle GHG emissions than changing the length of CO 2 transport pipeline. Finally, it is concluded from the current study that while the global warming potential is reduced when MEA-based CO 2 capture is employed, the increase in other air pollutants such as NO x and NH 3 leads to higher eutrophication and acidification potentials

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

International Nuclear Information System (INIS)

Placco, Guilherme M.; Guimaraes, Lamartine N.F.; Santos, Rubens S. dos

2013-01-01

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)

Performance analysis of a bio-gasification based combined cycle power plant employing indirectly heated humid air turbine

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, S., E-mail: sankha.deepp@gmail.com; Mondal, P., E-mail: mondal.pradip87@gmail.com; Ghosh, S., E-mail: sudipghosh.becollege@gmail.com [Department of Mechanical Engineering, Indian Institute of Engineering Science and Technology, Shibpur, Howrah – 711103, West Bengal (India)

2016-07-12

Rapid depletion of fossil fuel has forced mankind to look into alternative fuel resources. In this context, biomass based power generation employing gas turbine appears to be a popular choice. Bio-gasification based combined cycle provides a feasible solution as far as grid-independent power generation is concerned for rural electrification projects. Indirectly heated gas turbine cycles are promising alternatives as they avoid downstream gas cleaning systems. Advanced thermodynamic cycles have become an interesting area of study to improve plant efficiency. Water injected system is one of the most attractive options in this field of applications. This paper presents a theoretical model of a biomass gasification based combined cycle that employs an indirectly heated humid air turbine (HAT) in the topping cycle. Maximum overall electrical efficiency is found to be around 41%. Gas turbine specific air consumption by mass is minimum when pressure ratio is 6. The study reveals that, incorporation of the humidification process helps to improve the overall performance of the plant.

``Turbo-KWK `99``. Combined-cycle power stations with gas turbines. Technical meeting; Turbo-KWK `99. Kraft-Waerme-Kopplung mit Gasturbinen. Fachtagung

Energy Technology Data Exchange (ETDEWEB)

1999-09-01

This conference report comprises 18 contributions on the technological success of gas turbines in power generation, e.g.: Maximum power generation efficiency of combined cycle systems, flexibility of power generation, reduction of air pollution, hot gas production for drying processes and environment-friendly cold generation in the pharmaceutical and printing industries. The final contribution presents an outlook to the future.

Strain measurements of nuclear power plant steam generator antiseismic supports

International Nuclear Information System (INIS)

Kulichevsky, R.

1997-01-01

The nuclear power plants steam generators have different types of structural supports. One of these types are the antiseismic supports, which are intended to be under stress only if a seismic event takes place. Nevertheless, the antiseismic supports lugs, that are welded to the steam generator vessel, are subjected to thermal fatigue because of the temperature cycles related with the shut down and start up operations performed during the life of the nuclear power plant. In order to evaluate the stresses that the lugs are subjected to, several strain gages were welded on two supports lugs, positioned at two heights of one of the Embalse nuclear power plant steam generators. In this paper, the instrumentation used and the strain measurements obtained during two start up operations are presented. The influence of the plant start up operation parameters on the lugs strain evolution is also analyzed. (author) [es

Power generation

International Nuclear Information System (INIS)

Nunez, Anibal D.

2001-01-01

In the second half of twentieth century, nuclear power became an industrial reality. Now the operating 433 power plants, the 37 plants under construction, near 9000 years/reactor with only one serious accident with emission of radioactive material to the environment (Chernobyl) show the maturity of this technology. Today nuclear power contribute a 17% to the global generation and an increase of 75 % of the demand of electricity is estimated for 2020 while this demand is expected to triplicate by 2050. How this requirement can be satisfied? All the indicators seems to demonstrate that nuclear power will be the solution because of the shortage of other sources, the increase of the prices of the non renewable fuels and the scarce contribution of the renewable ones. In addition, the climatic changes produced by the greenhouse effect make even more attractive nuclear power. The situation of Argentina is analyzed and compared with other countries. The convenience of an increase of nuclear power contribution to the total national generation seems clear and the conclusion of the construction of the Atucha II nuclear power plant is recommended

Energy Optimization for a Weak Hybrid Power System of an Automobile Exhaust Thermoelectric Generator

Science.gov (United States)

Fang, Wei; Quan, Shuhai; Xie, Changjun; Tang, Xinfeng; Ran, Bin; Jiao, Yatian

2017-11-01

An integrated starter generator (ISG)-type hybrid electric vehicle (HEV) scheme is proposed based on the automobile exhaust thermoelectric generator (AETEG). An eddy current dynamometer is used to simulate the vehicle's dynamic cycle. A weak ISG hybrid bench test system is constructed to test the 48 V output from the power supply system, which is based on engine exhaust-based heat power generation. The thermoelectric power generation-based system must ultimately be tested when integrated into the ISG weak hybrid mixed power system. The test process is divided into two steps: comprehensive simulation and vehicle-based testing. The system's dynamic process is simulated for both conventional and thermoelectric powers, and the dynamic running process comprises four stages: starting, acceleration, cruising and braking. The quantity of fuel available and battery pack energy, which are used as target vehicle energy functions for comparison with conventional systems, are simplified into a single energy target function, and the battery pack's output current is used as the control variable in the thermoelectric hybrid energy optimization model. The system's optimal battery pack output current function is resolved when its dynamic operating process is considered as part of the hybrid thermoelectric power generation system. In the experiments, the system bench is tested using conventional power and hybrid thermoelectric power for the four dynamic operation stages. The optimal battery pack curve is calculated by functional analysis. In the vehicle, a power control unit is used to control the battery pack's output current and minimize energy consumption. Data analysis shows that the fuel economy of the hybrid power system under European Driving Cycle conditions is improved by 14.7% when compared with conventional systems.

Electricity, nuclear power and fuel cycle in OECD countries, main data 1987

International Nuclear Information System (INIS)

1987-01-01

A questionnaire on Electricity Generation. Nuclear Power and Fuel Cycle Data is distributed annually to OECD Member Countries. In the questionnaire of January 1987, countries were asked to provide historical data for 1985 and 1986 and most likely projections up to the year 2005. The replies to the questionnaire or the results of the discussions between national correspondents and the Secretariat are presented in this Booklet. The Secretariat has, in some cases, referred to IEA's electricity-related data and IAEA's nuclear plant data. Where data were still unavailable the Secretariat made estimates based on information from other sources. Data for 1986 are provisional for several countries. The data on electricity generation and electric capacity are presented to the year 2005, and the data on fuel cycle services to the year 2000. The installed nuclear capacity of the OECD countries for the year 2000 is estimated at 340 GWe, a 25 GWe reduction from the estimate in the 1986 Booklet. This reduction is mainly due to revised lower projections of electricity demand. The Addendum contains an analysis of the present and past projections for installed nuclear capacity to 2000. It shows the total capacity of those plants connected to the grid, under construction and firmly planned to be in operation in 2000 as 294 GWe. The new projection of 340 GWe is well above this estimate, indicating that some countries are still planning to expand their nuclear capacities. In only one country does it appear that planned expansion has been affected specifically by the Chernobyl accident. The electricity generation and production data for fuel cycle services refer to those facilities located within the country, and thus exclude imports. The fuel cycle requirements, however, refer to the amounts of fuel cycle materials and services necessary for national nuclear power programmes

Advanced Accelerated Power Cycling Test for Reliability Investigation of Power Device Modules

DEFF Research Database (Denmark)

Choi, Uimin; Jørgensen, Søren; Blaabjerg, Frede

2016-01-01

This paper presents an apparatus and methodology for an advanced accelerated power cycling test of insulated-gate bipolar transistor (IGBT) modules. In this test, the accelerated power cycling test can be performed under more realistic electrical operating conditions with online wear-out monitoring...... of tested power IGBT module. The various realistic electrical operating conditions close to real three-phase converter applications can be achieved by the simple control method. Further, by the proposed concept of applying the temperature stress, it is possible to apply various magnitudes of temperature...... swing in a short cycle period and to change the temperature cycle period easily. Thanks to a short temperature cycle period, test results can be obtained in a reasonable test time. A detailed explanation of apparatus such as configuration and control methods for the different functions of accelerated...

Thermoeconomic Analysis of Hybrid Power Plant Concepts for Geothermal Combined Heat and Power Generation

Directory of Open Access Journals (Sweden)

Florian Heberle

2014-07-01

Full Text Available We present a thermo-economic analysis for a low-temperature Organic Rankine Cycle (ORC in a combined heat and power generation (CHP case. For the hybrid power plant, thermal energy input is provided by a geothermal resource coupled with the exhaust gases of a biogas engine. A comparison to alternative geothermal CHP concepts is performed by considering variable parameters like ORC working fluid, supply temperature of the heating network or geothermal water temperature. Second law efficiency as well as economic parameters show that hybrid power plants are more efficient compared to conventional CHP concepts or separate use of the energy sources.

Safety analysis program for steam generators replacement and power uprate at Tihange 2 nuclear power plant

International Nuclear Information System (INIS)

Delhaye, X.; Charlier, A.; Damas, Ph.; Druenne, H.; Mandy, C.; Parmentier, F.; Pirson, J.; Zhang, J.

2002-01-01

The Belgian Tihange 2 nuclear power plant went into commercial operation in 1983 producing a thermal power of 2785 MW. Since the commissioning of the plant the steam generators U-tubes have been affected by primary stress corrosion cracking. In order to avoid further degradation of the performance and an increase in repair costs, Electrabel, the owner of the plant, decided in 1997 to replace the 3 steam generators. This decision was supported by the feasibility study performed by Tractebel Energy Engineering which demonstrated that an increase of 10% of the initial power together with a fuel cycle length of 18 months was achieved. Tractebel Energy Engineering was entrusted by Electrabel as the owner's engineer to manage the project. This paper presents the role of Tractebel Energy Engineering in this project and the safety analysis program necessary to justify the new operation point and the fuel cycle extension to 18 months re-analysis of FSAR chapter 15 accidents and verification of the capacity of the safety and auxiliary systems. The FSAR chapter 15 accidents were reanalyzed jointly by Framatome and Tractebel Energy Engineering while the systems verifications were carried out by Tractebel Energy Engineering. (author)

An advanced conceptual Tokamak fusion power reactor utilizing closed cycle helium gas turbines

International Nuclear Information System (INIS)

Conn, R.W.

1976-01-01

UWMAK-III is a conceptual Tokamak reactor designed to study the potential and the problems associated with an advanced version of Tokamaks as power reactors. Design choices have been made which represent reasonable extrapolations of present technology. The major features are the noncircular plasma cross section, the use of TZM, a molybdenum based alloy, as the primary structural material, and the incorporation of a closed-cycle helium gas turbine power conversion system. A conceptual design of the turbomachinery is given together with a preliminary heat exchanger analysis that results in relatively compact designs for the generator, precooler, and intercooler. This paper contains a general description of the UWMAK-III system and a discussion of those aspects of the reactor, such as the burn cycle, the blanket design and the heat transfer analysis, which are required to form the basis for discussing the power conversion system. The authors concentrate on the power conversion system and include a parametric performance analysis, an interface and trade-off study and a description of the reference conceptual design of the closed-cycle helium gas turbine power conversion system. (Auth.)

Life-cycle air emissions from PV power systems

International Nuclear Information System (INIS)

Watt, M.E.; Johnson, A.J.; Outhred, H.R.; Ellis, M.

1998-01-01

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)

Thermo-economic performance of HTGR Brayton power cycles

International Nuclear Information System (INIS)

Linares, J. L.; Herranz, L. E.; Moratilla, B. Y.; Fernandez-Perez, A.

2008-01-01

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)

Self-Powered Functional Device Using On-Chip Power Generation

KAUST Repository

Hussain, Muhammad Mustafa

2012-01-26

An apparatus, system, and method for a self-powered device using on-chip power generation. In some embodiments, the apparatus includes a substrate, a power generation module on the substrate, and a power storage module on the substrate. The power generation module may include a thermoelectric generator made of bismuth telluride.

Self-Powered Functional Device Using On-Chip Power Generation

KAUST Repository

Hussain, Muhammad Mustafa

2012-01-01

An apparatus, system, and method for a self-powered device using on-chip power generation. In some embodiments, the apparatus includes a substrate, a power generation module on the substrate, and a power storage module on the substrate. The power generation module may include a thermoelectric generator made of bismuth telluride.

Optimization of a recompression supercritical carbon dioxide cycle for an innovative central receiver solar power plant

International Nuclear Information System (INIS)

Reyes-Belmonte, M.A.; Sebastián, A.; Romero, M.; González-Aguilar, J.

2016-01-01

Peculiar thermodynamic properties of carbon dioxide (CO 2 ) when it is held at or above its critical condition (stated as supercritical CO 2 or sCO 2 ) have attracted the attention of many researchers. Its excellent thermophysical properties at medium-to-moderate temperature range have made it to be considered as the alternative working fluid for next power plant generation. Among those applications, future nuclear reactors, solar concentrated thermal energy or waste energy recovery have been shown as the most promising ones. In this paper, a recompression sCO 2 cycle for a solar central particles receiver application has been optimized, observing net cycle efficiency close to 50%. However, small changes on cycle parameters such as working temperatures, recuperators efficiencies or mass flow distribution between low and high temperature recuperators were found to drastically modify system overall efficiency. In order to mitigate these uncertainties, an optimization analysis based on recuperators effectiveness definition was performed observing that cycle efficiency could lie among 40%–50% for medium-to-moderate temperature range of the studied application (630 °C–680 °C). Due to the lack of maturity of current sCO 2 technologies and no power production scale demonstrators, cycle boundary conditions based on the solar application and a detailed literature review were chosen. - Highlights: • Mathematical modelling description for recompression sCO 2 cycle. • Split fraction and recuperators effectiveness effect into sCO 2 cycle performance. • Optimization methodology of sCO 2 cycle for an innovative solar central receiver. • Power generation using particles central receiver.

Low grade heat driven adsorption system for cooling and power generation using advanced adsorbent materials

International Nuclear Information System (INIS)

Al-Mousawi, Fadhel Noraldeen; Al-Dadah, Raya; Mahmoud, Saad

2016-01-01

Highlights: • Adsorption system based on water and advanced physical adsorbents has the potential of producing cooling and power. • Adding an expander to physisorption system enhances efficiency by up to 11%. • MIL101Cr MOF can produce 95 W/kg and 1357 W/kg of specific power and cooling. • AQSOA Z02 can produce 73 W/kg and 640 W/kg of specific power and cooling. - Abstract: Globally there is abundance of low grade heat sources (around 150 °C) from renewables like solar energy or from industrial waste heat. The exploitation of such low grade heat sources will reduce fossil fuel consumption and CO_2 emissions. Adsorption technology offers the potential of using such low grade heat to generate cooling and power. In this work, the effect of using advanced adsorbent materials like AQSOA-Z02 (SAPO-34) zeolite and MIL101Cr Metal Organic Framework (MOF) at various operating conditions on power and cooling performance compared to that of commonly used silica-gel was investigated using water as refrigerant. A mathematical model for a two bed adsorption cooling cycle has been developed with the cycle modified to produce power by incorporating an expander between the desorber and the condenser. Results show that it is possible to produce power and cooling at the same time without affecting the cooling output. Results also show that for all adsorbents used as the heat source temperature increases, the cooling effect and power generated increase. As for increasing the cold bed temperature, this will decrease the cooling effect and power output except for SAPO-34 which shows slightly increasing trend of cooling and power output. As the condenser cooling temperature increases, the cooling effect and power output will decrease while for the chilled water temperature, the cooling load and power generated increased as the temperature increased. The maximum values of average specific power generation (SP), specific cooling power (SCP) and cycle efficiency are 73 W

Power generating device

Energy Technology Data Exchange (ETDEWEB)

Onodera, Toshihiro

1989-05-02

The existing power generating device consisting of static components only lacks effective measures to utilize solar energy and maintain power generation, hence it is inevitable to make the device much larger and more complicated in order to utilize it as the primary power source for artificial satellites. In view of the above, in order to offer a power generating device useful for the primary power source for satellites which is simple and can keep power generation by solar energy, this invention proposes a power generating device composed of the following elements: (1) a rectangular parallelopiped No. II superconductor plate; (2) a measure to apply a magnetic field to one face of the above superconductor plate; (3) a measure to provide a temperature difference within the range between the starting temperature and the critical temperature of superconductivity to a pair of faces meeting at right angles with the face to which the magnetic field was applied by the above measure; (4) a measure to provide an electrode on each of the other pair of faces meeting at right angles with the face to which the magnetic field was applied by the above measure and form a closed circuit by connecting the each electrode above to each of a pair of electrodes of the load respectively; and (5) a switching measure which is installed in the closed circuit prepared by the above measure and shuts off the closed circuit when the direction of the electric current running the above closed circuit is reversed. 6 figs.

Parametric optimization design for supercritical CO2 power cycle using genetic algorithm and artificial neural network

International Nuclear Information System (INIS)

Wang Jiangfeng; Sun Zhixin; Dai Yiping; Ma Shaolin

2010-01-01

Supercritical CO 2 power cycle shows a high potential to recover low-grade waste heat due to its better temperature glide matching between heat source and working fluid in the heat recovery vapor generator (HRVG). Parametric analysis and exergy analysis are conducted to examine the effects of thermodynamic parameters on the cycle performance and exergy destruction in each component. The thermodynamic parameters of the supercritical CO 2 power cycle is optimized with exergy efficiency as an objective function by means of genetic algorithm (GA) under the given waste heat condition. An artificial neural network (ANN) with the multi-layer feed-forward network type and back-propagation training is used to achieve parametric optimization design rapidly. It is shown that the key thermodynamic parameters, such as turbine inlet pressure, turbine inlet temperature and environment temperature have significant effects on the performance of the supercritical CO 2 power cycle and exergy destruction in each component. It is also shown that the optimum thermodynamic parameters of supercritical CO 2 power cycle can be predicted with good accuracy using artificial neural network under variable waste heat conditions.

Nuclear power generation

International Nuclear Information System (INIS)

Hirao, Katumi; Sato, Akira; Kaimori, Kimihiro; Kumano, Tetsuji

2001-01-01

Nuclear power generation for commercial use in Japan has passed 35 years since beginning of operation in the Tokai Nuclear Power Station in 1966, and has 51 machines of reactor and about 44.92 MW of total output of equipment scale in the 21st century. However, an environment around nuclear energy becomes severer at present, and then so many subjects to be overcome are remained such as increased unreliability of the public on nuclear energy at a chance of critical accident of the JCO uranium processing facility, delay of pull-thermal plan, requirement for power generation cost down against liberalization of electric power, highly aging countermeasure of power plant begun its operation as its Genesis, and so on. Under such conditions, in order that nuclear power generation in Japan survives as one of basic electric source in future, it is necessary not only to pursue safety and reliability of the plant reliable to the public, but also to intend to upgrade its operation and maintenance by positively adopting good examples on operational management method on abroad and to endeavor further upgrading of application ratio of equipments and reduction of generation cost. Here were outlined on operation conditions of nuclear power stations in Japan, and introduced on upgrading of their operational management and maintenance management. (G.K.)

Improvements of characteristics of open cycle Faraday type MHD power generator

International Nuclear Information System (INIS)

Yoshida, Masaharu; Umoto, Juro; Aoki, Sigeo

1982-01-01

MHD power generators are classified into two types: Faraday type and diagonal type (including Hall type). It is considered also in Faraday type generators that the characteristics can be improved further by selecting the aspect ratio appropriately, and employing cap electrodes which approach diagonal conducting side-wall type from parallel plate electrodes. First, the three-dimensional analysis using a new equivalent circuit is introduced, in which finite electrode division and working gas boundary layer are considered using the generalized Ohm's law, Maxwell's electromagnetic equations and others. The above described improvement of characteristics is investigated numerically fully applying this analyzing method. If the wall temperature is low, the increase in the aspect ratio of a generating duct cross-section considerably improves the characteristics because plasma non-uniformity decreases. If the cap electrodes having an optimum side-wall length are used, the output increases considerably because the load current is given and received through the side-wall electrodes. Efficiency is a little lower than the case using parallel plate electrodes. Therefore, if the aspect ratio is taken sufficiently large, and the cap electrodes with optimum side-wall electrode length are used, the generator characteristics are greatly improved since the above mentioned effects are multiplied. (Wakatsuki, Y.)

Nuclear power generation and nuclear non-proliferation

International Nuclear Information System (INIS)

Rathjens, G.

1979-01-01

The main points existing between nuclear energy development and nuclear non-proliferation policy are reviewed. The solar energy and other energy will replace for nuclear fission energy in the twenty first century, but it may not occur in the first half, and the structure has to be established to continue the development of nuclear fission technology, including breeder reactor technology. In the near future, it should be encouraged to use advanced thermal reactors if they are economic and operated with safety. Miserable results may be created in the worldwide scale, if a serious accident occurs anywhere or nuclear power reactors are utilized for military object. It is estimated to be possible to develop the ability of manufacturing nuclear weapons within two or three years in the countries where the industry is highly developed so as to generate nuclear power. It is also difficult to take measures so that nuclear power generation does not increase nuclear proliferation problems, and it is necessary to mitigate the motive and to establish the international organization. Concensus exists that as the minimum security action, the storage and transportation of materials, which can be directly utilized for nuclear weapons, should be decided by the international system. The most portions of sensitive nuclear fuel cycle should be put under the international management, as far as possible. This problem is discussed in INFCE. Related to the nuclear nonproliferation, the difference of policy in fuel cycle problems between USA and the other countries, the enrichment of nuclear fuel material, especially the reasons to inhibit the construction of additional enrichment facilities, nuclear fuel reprocessing problems, radioactive waste disposal, plutonium stock and plutonium recycle problems are reviewed. (Nakai, Y.)

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

Analysis of the backpressure effect of an Organic Rankine Cycle (ORC) evaporator on the exhaust line of a turbocharged heavy duty diesel power generator for marine applications

International Nuclear Information System (INIS)

Michos, Constantine N.; Lion, Simone; Vlaskos, Ioannis; Taccani, Rodolfo

2017-01-01

Highlights: • Waste heat recovery on internal combustion engines is studied. • The backpressure effect of the Organic Rankine Cycle boiler has been evaluated. • Three different state-of-the art turbocharging technologies have been assessed. • Six different fluids for medium-high temperature recovery have been considered. • A reduction up to 10% in fuel consumption can be achieved. - Abstract: In marine and power generation sectors, waste heat recovery technologies are attracting growing attention in order to increase heavy duty diesel engines efficiency and decrease fuel consumption, with the purpose of respecting stringent emissions legislations. In this work, the backpressure effect of an Organic Rankine Cycle (ORC) evaporator on the exhaust line of a turbocharged, V12 heavy duty diesel engine, for typical marine and power generation applications has been investigated using the commercial software Ricardo WAVE. Three different state-of-the art turbocharging strategies are assessed in order to counterbalance the increased pumping losses of the engine due to the boiler installation: fixed turbine, Waste-Gate (WG) and Variable Geometry Turbine (VGT). At the same time, the steady-state thermodynamic performance of two different ORC configurations, simple tail-pipe evaporator and recuperated simple tail-pipe evaporator layouts, are assessed, with the scope of further increasing the engine power output, recovering unutilized exhaust gas heat. Several different working fluids, suitable for medium-high temperature waste heat recovery, are evaluated and screened, considering, as well, health and safety issues. Thermodynamic cycle parameters such as, for example, evaporation and condensing pressures, working fluid mass flow and cycle temperatures, are optimized in order to obtain the maximum improvement in Brake Specific Fuel Consumption (bsfc). From the engine side point of view, a VGT turbocharger is the most favorable solution to withstand increased

Thermodynamic and economic studies of two new high efficient power-cooling cogeneration systems based on Kalina and absorption refrigeration cycles

International Nuclear Information System (INIS)

Rashidi, Jouan; Ifaei, Pouya; Esfahani, Iman Janghorban; Ataei, Abtin; Yoo, Chang Kyoo

2016-01-01

Highlights: • Proposing two new power and cooling cogeneration systems based on absorption chillers and Kalina cycles. • Model-based comparison through thermodynamic and economic standpoints. • Investigating sensitivity of system performance and costs to the key parameters. • Reducing total annual costs of the base system up to 8% by cogeneration. • Increasing thermal efficiency up to 4.9% despite of cooling generation. - Abstract: Two new power and cooling cogeneration systems based on Kalina cycle (KC) and absorption refrigeration cycle (AC) are proposed and studied from thermodynamic and economic viewpoints. The first proposed system, Kalina power-cooling cycle (KPCC), combines the refrigerant loop of the water-ammonia absorption chiller, consisting of an evaporator and two throttling valves with the KC. A portion of the KC mass flow enters the evaporator to generate cooling after being condensed in the KPCC system. KPCC is a flexible system adapting power and cooling cogeneration to the demand. The second proposed system, Kalina lithium bromide absorption chiller cycle (KLACC), consists of the KC and a single effect lithium bromide-water absorption chiller (AC_L_i_B_r_-_w_a_t_e_r). The KC subsystem discharges heat to the AC_L_i_B_r_-_w_a_t_e_r desorber before condensing in the condenser. The performance and economic aspects of both proposed systems are analyzed and compared with the stand alone KC. A parametric analysis is conducted to evaluate the sensitivity of efficiencies and the generated power and cooling quantities to the key operating variables. The results showed that, thermal efficiency and total annual costs decreased by 5.6% and 8% for KPCC system but increased 4.9% and 58% for KLACC system, respectively. Since the power-cooling efficiency of KLACC is 42% higher than KPCC it can be applied where the aim is cooling generation without considering economic aspects.

Optimization of a single stage inverter with one cycle control for photovoltaic power generation

Energy Technology Data Exchange (ETDEWEB)

Egiziano, L.; Femia, N.; Granozio, D.; Petrone, G.; Spagnuolo, G. [Salermo Univ., Salermo (Italy); Vitelli, M. [Seconda Univ. di Napoli, Napoli (Italy)

2006-07-01

An optimized one-cycle control (OCC) for maximum power point tracking and power factor correction in grid-connected photovoltaic (PV) applications was described. OCC is a nonlinear control technique that rejects line perturbations and allows both output power factor co-reaction and tracking of input PV fields. An OCC system was analyzed in order to select optimal design parameters. Parameters were refined through the selection of suitable design constraints. A stochastic search was then performed. Criteria were then developed to distinguish appropriate design parameters for the optimized OCC. The optimization was based on advanced heuristic techniques for non-linear constrained optimization. Performance indices were calculated for each feasible set of parameters. A customized perturb and observe control was then applied to the single-stage inverter. Results of the optimization process were validated by a series of time-domain simulations conducted under heavy, varying irradiance conditions. Results of the simulations showed that the optimized controllers showed improved performance in terms of power drawn from the PV field. 7 refs., 1 tab., 5 figs.

Analysis of a Temperature-Controlled Exhaust Thermoelectric Generator During a Driving Cycle

Science.gov (United States)

Brito, F. P.; Alves, A.; Pires, J. M.; Martins, L. B.; Martins, J.; Oliveira, J.; Teixeira, J.; Goncalves, L. M.; Hall, M. J.

2016-03-01

Thermoelectric generators can be used in automotive exhaust energy recovery. As car engines operate under wide variable loads, it is a challenge to design a system for operating efficiently under these variable conditions. This means being able to avoid excessive thermal dilution under low engine loads and being able to operate under high load, high temperature events without the need to deflect the exhaust gases with bypass systems. The authors have previously proposed a thermoelectric generator (TEG) concept with temperature control based on the operating principle of the variable conductance heat pipe/thermosiphon. This strategy allows the TEG modules’ hot face to work under constant, optimized temperature. The variable engine load will only affect the number of modules exposed to the heat source, not the heat transfer temperature. This prevents module overheating under high engine loads and avoids thermal dilution under low engine loads. The present work assesses the merit of the aforementioned approach by analysing the generator output during driving cycles simulated with an energy model of a light vehicle. For the baseline evaporator and condenser configuration, the driving cycle averaged electrical power outputs were approximately 320 W and 550 W for the type-approval Worldwide harmonized light vehicles test procedure Class 3 driving cycle and for a real-world highway driving cycle, respectively.

Application of Biomass from Palm Oil Mill for Organic Rankine Cycle to Generate Power in North Sumatera Indonesia

Science.gov (United States)

Nur, T. B.; Pane, Z.; Amin, M. N.

2017-03-01

Due to increasing oil and gas demand with the depletion of fossil resources in the current situation make efficient energy systems and alternative energy conversion processes are urgently needed. With the great potential of resources in Indonesia, make biomass has been considered as one of major potential fuel and renewable resource for the near future. In this paper, the potential of palm oil mill waste as a bioenergy source has been investigated. An organic Rankine cycle (ORC) small scale power plant has been preliminary designed to generate electricity. The working fluid candidates for the ORC plant based on the heat source temperature domains have been investigated. The ORC system with a regenerator has higher thermal efficiency than the basic ORC system. The study demonstrates the technical feasibility of ORC solutions in terms of resources optimizations and reducing of greenhouse gas emissions.

Experimental and CFD Analysis of Printed Circuit Heat Exchanger for Supercritical CO{sub 2} Power Cycle Application

Energy Technology Data Exchange (ETDEWEB)

Baik, Seungjoon; Kim, Hyeon Tae; Kim, Seong Gu; Lee, Jekyoung; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

2015-10-15

The supercritical carbon dioxide (S-CO{sub 2}) power cycle has been suggested as an alternative for the SFR power generation system. First of all, relatively mild sodium-CO{sub 2} interaction can reduce the accident probability. Also the S-CO{sub 2} power conversion cycle can achieve high efficiency with SFR core thermal condition. Moreover, the S-CO{sub 2} power cycle can reduce cycle footprint due to high density of the working fluid. Recently, various compact heat exchangers have been studied for developing an optimal heat exchanger. In this paper, the printed circuit heat exchanger was selected for S-CO{sub 2} power cycle applications and was closely investigated experimentally and analytically. Recently, design and performance prediction of PCHE received attention due to its importance in high pressure power systems such as S-CO{sub 2} cycle. To evaluate a PCHE performance with CO{sub 2} to water, KAIST research team designed and tested a lab-scale PCHE. From the experimental data and CFD analysis, pressure drop and heat transfer correlations are obtained. For the CFD analysis, Ansys-CFX commercial code was utilized with RGP table implementation. In near future, the turbulence model sensitivity study will be followed.

Thermal performance of Brayton power cycles. A study based on high-temperature gas-cooled reactors

International Nuclear Information System (INIS)

Herranz, Luis E.; Linares, Jose I.; Moratilla, Beatriz Y.

2005-01-01

Power cycles optimization has become an essential ingredient to achieve sustainability and improve economic competitiveness of forthcoming Generation IV designs. This paper investigates performance of several configurations of direct helium Brayton cycles. An optimum layout is proposed based on multiple intercooled compression stages and in-between turbines reheating: C(IC) 2 HTRTX. Under the hypotheses and approximations made, a 59% is estimated and it increases even further (67%) when the foreseen technological development is considered. A sensitive analysis identified key components and variables for cycle performance. Particular attention is paid to the effect of the extracted gas mass fraction for reheating. It is shown that the C(IC) 2 HTRTX cycle provides a feasible and simple way to operate the power plant the load-follow mode with a very little loss of efficiency. (author)

Nuclear power and the nuclear fuel cycle

Energy Technology Data Exchange (ETDEWEB)

NONE

1976-07-01

The IAEA is organizing a major conference on nuclear power and the nuclear fuel cycle, which is to be held from 2 to 13 May 1977 in Salzburg, Austria. The programme for the conference was published in the preceding issue of the IAEA Bulletin (Vol.18, No. 3/4). Topics to be covered at the conference include: world energy supply and demand, supply of nuclear fuel and fuel cycle services, radioactivity management (including transport), nuclear safety, public acceptance of nuclear power, safeguarding of nuclear materials, and nuclear power prospects in developing countries. The articles in the section that follows are intended to serve as an introduction to the topics to be discussed at the Salzburg Conference. They deal with the demand for uranium and nuclear fuel cycle services, uranium supplies, a computer simulation of regional fuel cycle centres, nuclear safety codes, management of radioactive wastes, and a pioneering research project on factors that determine public attitudes toward nuclear power. It is planned to present additional background articles, including a review of the world nuclear fuel reprocessing situation and developments in the uranium enrichment industry, in future issues of the Bulletin. (author)

A combined power cycle utilizing low-temperature waste heat and LNG cold energy

International Nuclear Information System (INIS)

Shi Xiaojun; Che Defu

2009-01-01

This paper has proposed a combined power system, in which low-temperature waste heat can be efficiently recovered and cold energy of liquefied natural gas (LNG) can be fully utilized as well. This system consists of an ammonia-water mixture Rankine cycle and an LNG power generation cycle, and it is modelled by considering mass, energy and species balances for every component and thermodynamic analyses are conducted. The results show that the proposed combined cycle has good performance, with net electrical efficiency and exergy efficiency of 33% and 48%, respectively, for a typical operating condition. The power output is equal to 1.25 MWh per kg of ammonia-water mixture. About 0.2 MW of electrical power for operating sea water pumps can be saved. Parametric analyses are performed for the proposed combined cycle to evaluate the effects of key factors on the performance of the proposed combined cycle through simulation calculations. Results show that a maximum net electrical efficiency can be obtained as the inlet pressure of ammonia turbine increases and the peak value increases as the ammonia mass fraction increases. Exergy efficiency goes up with the increased ammonia turbine inlet pressure. With the ammonia mass fraction increases, the net electrical efficiency increases, whereas exergy efficiency decreases. For increasing LNG turbine inlet pressure or heat source temperature, there is also a peak of net electrical efficiency and exergy efficiency. With the increase of LNG gas turbine outlet pressure, exergy efficiency increases while net electrical efficiency drops

Renewable energies for power generation

International Nuclear Information System (INIS)

Freris, L.; Infield, D.

2009-01-01

Power generation from renewable energy sources is different from power generation from classical energies (nuclear, thermal..). Therefore, the integration into the grid of the electricity supplied by renewable sources requires a deep thinking. The reason is that these power sources are controlled by variable elements, like wind, water and sun, which condition production. This book deals with the following aspects in detail: characteristics of classical and intermittent generators; grid balancing between supply and demand; conversion methods of renewable energies into electricity; power systems; privatizing of power generation and birth of new markets, in particular the 'green' power market; development of renewable energies thanks to technical advances. It gives a comprehensive overview of the present day available renewable energy sources for power generation. (J.S.)

Thermodynamic Analysis of a Rankine Cycle Powered Vapor Compression Ice Maker Using Solar Energy

Directory of Open Access Journals (Sweden)

Bing Hu

2014-01-01

Full Text Available To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with increasing generation temperature. For every working fluid there is an optimal generation temperature at which organic Rankine efficiency achieves the maximum value. The cooling power per square meter collector and ice production per square meter collector per day are, respectively, 126.44 W m−2 and 7.61 kg m−2 day−1 at the generation temperature of 140°C for working fluid of R245fa, which demonstrates the feasibility of organic Rankine cycle powered vapor compression ice maker.

Feasibility study for application of mixture working fluid cycle to nuclear reactor power plant

International Nuclear Information System (INIS)

Takeuchi, Yutaka; Ohshima, Iwao; Shiomi, Hirozo; Miyamae, Nobuhiko; Hiramatsu, Miki; Montani, Mitsuto

1999-01-01

There exists a large amount of unused energy in nuclear power plants. However, it consists of relatively low temperature energy, so it is difficult to generate electricity by the conventional water-steam cycle. In order to utilize such low temperature energy, we applied a mixture working fluid cycle called as the Kalina cycle to a light water nuclear reactor power plant. The Kalina cycle uses a working fluid composed of ammonia and water to create a variable temperature boiling process. We applied a saturation type Kalina cycle with single stage ammonia-water separation process as a bottoming cycle to a conventional water-steam cycle of a 1100MWe class BWR as an example case. The input heat source is the exhaust or the partial extraction of a low pressure turbine (LPT). A steady state chemical process modeling code ASPENPLUS was used for the sensitivity analyses. The maximum efficiency was calculated to be realized when using the lowest heat sink temperature, 8degC. The additional electrical output is about 95 MWe when using the exhaust of LPT and is about 127 MWe when using the partial extraction of LPT. Namely, about 4.3% of the exhaust heat for the former case and about 5.8% for the latter case can be utilized as electrical power, respectively. (author)

Life cycle analysis of photovoltaic cell and wind power plants

International Nuclear Information System (INIS)

Uchiyama, Yohji

1997-01-01

The paper presents life cycle analyses of net energy and CO 2 emissions on photovoltaic cell and wind power generation plants. Energy requirements associated with a plant are estimated for producing materials, manufacturing equipment, constructing facilities, acid operating plants. Energy ratio and net supplied energy are calculated by the process energy analysis that examines the entire energy inventory of input and output during life time of a plant. Life cycle CO 2 emission can also be calculated from the energy requirements obtained by the net energy analysis. The emission also includes greenhouse effect equivalent to CO 2 emission of methane gas leakage at a mining as well as CO 2 emissions from fossil fuel combustion during generating electricity, natural gas treatment at an extracting well and cement production in industry. The commercially available and future-commercial technologies are dealt with in the study. Regarding PV technologies, two different kinds of installation are investigated; roof-top typed installation of residential houses and ground installation of electric utilities. (author)

Philosophy of power generation

International Nuclear Information System (INIS)

Amein, H.; Joyia, Y.; Qureshi, M.N.; Asif, M.

1995-01-01

In view of the huge power demand in future, the capital investment requirements for the development of power projects to meet the future energy requirements are so alarming that public sector alone cannot manage to raise funds and participation of the private sector in power generation development has become imperative. This paper discusses a power generation philosophy based on preference to the exploitation of indigenous resources and participation of private sector. In order to have diversification in generation resources, due consideration has been given to the development of nuclear power and even non-conventional but promising technologies of solar, wind, biomass and geothermal etc. (author)

Present status and future outlook of nuclear power generation in Japan

International Nuclear Information System (INIS)

Kunikazu Aisaka

1987-01-01

The structure of energy consumption in Japan is heavily dependent on imported oil, therefore Japan has been making its greatest effort in developing nuclear power among other alternatives of oil. The capacity factor of the nuclear power plants in Japan marked 76% in FY 1986, exceeding 70% level for the past several years. The share of nuclear power is expected to increase steadily in the future. Future scale of the nuclear power generation is projected as 62,000 MW in year 2000 and as 137,000 MW in 2030. Nuclear power is expected to produce 58% of the nation's total power generation in 2030. Under the present circumstances, Janpan is executing a nuclear energy policy based on the following guidelines: 1. Promoting the safety advancement program; 2. Improving LWR technologies; 3. Program on use of plutonium in thermal reactors; 4. Advanced thermal reactors (ATRs); 5. Promotion of FBR development; 6. Nuclear fuel cycle. (Liu)

Maturing Technologies for Stirling Space Power Generation

Science.gov (United States)

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

2016-01-01

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

Power cycle heat balance software for personal computer (PC)2TM

International Nuclear Information System (INIS)

Bockh, P. von; Rodriguez, H.

1996-01-01

This paper describes the PC-based power cycle balance of plant software (PC)trademark (Power Cycle on Personal Computer). It is designed to assist nuclear, fossil, and industrial power plants so that steam cycles can be simulated, analyzed and optimized. First, the cycle model is developed on the screen. The elements of the power cycle are taken from a tool box containing all components of a modern power cycle. The elements are connected by using a mouse. The next step is the input of the design values of the components or data taken from performance tests. This entire input sequence is guided by the program. Based on the input data, the physical behavior of each component is simulated according to established physical rules. Part load operation or other off-design conditions can be calculated. The program is designed for use by power plant engineers and power engineering firms to optimize new power cycles, perform problem-solving analyses, optimize component retrofit, and train power plant engineers and operators. It also can be used by universities to educate engineering students

Exergetic Analysis of an Integrated Tri-Generation Organic Rankine Cycle

Directory of Open Access Journals (Sweden)

Ratha Z. Mathkor

2015-08-01

Full Text Available This paper reports on a study of the modelling, validation and analysis of an integrated 1 MW (electrical output tri-generation system energized by solar energy. The impact of local climatic conditions in the Mediterranean region on the system performance was considered. The output of the system that comprised a parabolic trough collector (PTC, an organic Rankine cycle (ORC, single-effect desalination (SED, and single effect LiBr-H2O absorption chiller (ACH was electrical power, distilled water, and refrigerant load. The electrical power was produced by the ORC which used cyclopentane as working fluid and Therminol VP-1 was specified as the heat transfer oil (HTO in the collectors with thermal storage. The absorption chiller and the desalination unit were utilize the waste heat exiting from the steam turbine in the ORC to provide the necessary cooling energy and drinking water respectively. The modelling, which includes an exergetic analysis, focuses on the performance of the solar tri-generation system. The simulation results of the tri-generation system and its subsystems were produced using IPSEpro software and were validated against experimental data which showed good agreement. The tri-generation system was able to produce about 194 Ton of refrigeration, and 234 t/day distilled water.

Current Status and Future Outlook of Nuclear Power Generation in Japan

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Yasuro; Yoshii, Ryosuke

2007-07-01

For Japan, a country poor in natural resources, in light of the tough energy situation in recent times, a National Energy Strategy with energy security at its core was established in May 2006. The key point of the Strategy is nuclear power generation, and the aim is to ensure that nuclear power generation continues to account for 30 to 40 percent or more of total electricity generated even after 2030. The first step to achieving this goal is to make maximum use of existing plants (55 plants, 49580MWe), and the aim is to achieve a 60-year service life by making improvements to plant operation and maintenance, such as extending current monitoring and maintenance of plant condition, and the implementation of plant aging management. In Japan, plant construction has been continuous since the 1970s. The current new plant construction plan (13 plants, 17230MWe) is to be achieved with a concerted, cohesive national effort. In addition, in order to complete the nuclear fuel cycle, a reprocessing plant is being constructed strictly for peaceful use, and construction of a site for disposing of high-level radioactive waste is also proceeding. Development of the next generation light water reactors and fast breeder reactor cycle is also underway. (auth)

Dynamic Analysis of Permanent Magnet Synchronous Generator with Power Electronics

Directory of Open Access Journals (Sweden)

OZCIRA, S.

2010-05-01

Full Text Available Permanent magnet DC motor-generators (PMDC, PMSG have been widely used in industrial and energy sectors recently. Power control of these systems can be achieved by controlling the output voltage. In this study, PMDC-PMSG systems are mathematically modeled and simulated in MATLAB and Simulink software. Then the results are discussed. A low power permanent magnet synchronous generator is driven by a permanent magnet DC motor and the output voltage is controlled by a frequency cycle-converter. The output of a half-wave uncontrolled rectifier is applied to an SPWM inverter and the power is supplied to a 300V, 50Hz load. The load which is connected to an LC filter is modeled by state-space equations. LC filter is utilized in order to suppress the voltage oscillations at the inverter output.

Power generation costs. Coal - nuclear power

International Nuclear Information System (INIS)

1979-01-01

This supplement volume contains 17 separate chapters investigating the parameters which determine power generation costs on the basis of coal and nuclear power and a comparison of these. A detailed calculation model is given. The complex nature of this type of cost comparison is shown by a review of selected parameter constellation for coal-fired and nuclear power plants. The most favourable method of power generation can only be determined if all parameters are viewed together. One quite important parameter is the load factor, or rather the hours of operation. (UA) 891 UA/UA 892 AMO [de

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...

Optimization of biomass fuelled systems for distributed power generation using Particle Swarm Optimization

International Nuclear Information System (INIS)

Lopez, P. Reche; Reyes, N. Ruiz; Gonzalez, M. Gomez; Jurado, F.

2008-01-01

With sufficient territory and abundant biomass resources Spain appears to have suitable conditions to develop biomass utilization technologies. As an important decentralized power technology, biomass gasification and power generation has a potential market in making use of biomass wastes. This paper addresses biomass fuelled generation of electricity in the specific aspect of finding the best location and the supply area of the electric generation plant for three alternative technologies (gas motor, gas turbine and fuel cell-microturbine hybrid power cycle), taking into account the variables involved in the problem, such as the local distribution of biomass resources, transportation costs, distance to existing electric lines, etc. For each technology, not only optimal location and supply area of the biomass plant, but also net present value and generated electric power are determined by an own binary variant of Particle Swarm Optimization (PSO). According to the values derived from the optimization algorithm, the most profitable technology can be chosen. Computer simulations show the good performance of the proposed binary PSO algorithm to optimize biomass fuelled systems for distributed power generation. (author)

Effect of cycle coupling-configuration on energy cascade utilization for a new power and cooling cogeneration cycle

International Nuclear Information System (INIS)

Jing, Xuye; Zheng, Danxing

2014-01-01

Highlights: • A new power and cooling cogeneration cycle was proposed. • The thermophysical properties and the performance of the new cycle were calculated. • Different cycle coupling-configurations were analyzed. • The energy efficiency boosting mechanism of the new cycle was elucidated. - Abstract: To recover mid-low grade heat, a new power/cooling cogeneration cycle was proposed by combining the Kalina cycle and the double-effect ammonia–water absorption refrigeration (DAAR) cycle together, and the equivalent heat-to-power and exergy efficiencies of the cogeneration cycle reached 41.18% and 58.00%, respectively. To determine the effect of cycle coupling-configuration on energy cascade utilization for the new cycle, the cycle coupling-configuration of the Kalina and DAAR cycles were first analyzed, after which the cycle coupling-configuration of the new cycle was analyzed. Analysis results showed that the cycle coupling-configuration of the new cycle enhanced the energy cascade utilization. Furthermore, the energy efficiency boosting mechanism of the new cycle was elucidated