Net Power Output

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 3588 Experts worldwide ranked by ideXlab platform

Dietmar Kuhn - One of the best experts on this subject based on the ideXlab platform.

  • comparison of sub and supercritical organic rankine cycles for Power generation from low temperature low enthalpy geothermal wells considering specific Net Power Output and efficiency
    Applied Thermal Engineering, 2013
    Co-Authors: Christian Vetter, Hans Joachim Wiemer, Dietmar Kuhn
    Abstract:

    Abstract Electrical Power production at low-enthalpy (∼150 °C) geothermal sites is usually realized using an Organic Rankine Cycle (ORC process). This paper presents our analysis of sub- and supercritical processes using propane, carbon dioxide and ten other refrigerants as working fluids. The impact of crucial indicators for optimization, such as specific Net Power, thermal efficiency and heat input is discussed in detail. The focus was to optimize the thermodynamic loop and the influence of other parameters, such as condensing temperature, minimal temperature difference in the heat exchanger, and internal heat recovery. Simulations showed that at a geothermal fluid temperature of 150 °C, a suitable working fluid such as propane or R143a can increase specific Net Power Output up to 40%. Furthermore, systematic simulations on brine temperatures of 130–170 °C from subcritical to supercritical operation are discussed. Results from this research may also be applicable for electricity generation using waste heat from combined heat and Power (CHP) plants or other technical processes.

  • Comparison of sub- and supercritical Organic Rankine Cycles for Power generation from low-temperature/low-enthalpy geothermal wells, considering specific Net Power Output and efficiency
    Applied Thermal Engineering, 2012
    Co-Authors: Christian Vetter, Hans Joachim Wiemer, Dietmar Kuhn
    Abstract:

    Abstract Electrical Power production at low-enthalpy (∼150 °C) geothermal sites is usually realized using an Organic Rankine Cycle (ORC process). This paper presents our analysis of sub- and supercritical processes using propane, carbon dioxide and ten other refrigerants as working fluids. The impact of crucial indicators for optimization, such as specific Net Power, thermal efficiency and heat input is discussed in detail. The focus was to optimize the thermodynamic loop and the influence of other parameters, such as condensing temperature, minimal temperature difference in the heat exchanger, and internal heat recovery. Simulations showed that at a geothermal fluid temperature of 150 °C, a suitable working fluid such as propane or R143a can increase specific Net Power Output up to 40%. Furthermore, systematic simulations on brine temperatures of 130–170 °C from subcritical to supercritical operation are discussed. Results from this research may also be applicable for electricity generation using waste heat from combined heat and Power (CHP) plants or other technical processes.

Jiangfeng Wang - One of the best experts on this subject based on the ideXlab platform.

  • Comparative analysis on off-design performance of a novel parallel dual-pressure Kalina cycle for low-grade heat utilization
    Energy Conversion and Management, 2021
    Co-Authors: Zheng Shaoxiong, Yiping Dai, Chen Kang, Gang Fan, Pan Zhao, Jiangfeng Wang
    Abstract:

    Abstract In this paper, a novel parallel dual-pressure Kalina cycle system is presented to utilize the low-grade geothermal energy. In order to highlight the performance of the proposed cycle, the comparison of parallel dual-pressure Kalina cycle system and the basic Kalina cycle system is conducted and set at the same boundary conditions. The maximal Net Power Output of cycle is considered as the single-objective function based on particle swarm optimization algorithm. The exergy analysis and economic cost for both cycles are investigated at design conditions. Furthermore, as operating at off-design conditions, the variation ranges of geothermal energy mass flux and inlet temperature are 7.5–14 kg/s and 136–150 °C, respectively. The sliding pressure regulation strategy is applied to response to the variations of geothermal energy parameters. The two-levels evaporation pressures in the parallel dual-pressure Kalina cycle are adjusted to remain the invariable temperature difference between geothermal energy inlet temperature of evaporators and the corresponding turbine inlet temperature. The results show that, at design conditions, the maximal Net Power Output of parallel dual-pressure Kalina cycle and basic Kalina cycle is 329.62KW and 274.94KW, the corresponding exergy efficiency is 44.52% and 33.39%. Besides, the condenser contributes to the largest exergy destruction ratio in parallel dual-pressure Kalina cycle and basic Kalina cycle, which are 33.96% and 44.94% of overall exergy destruction, respectively. According to the off-design performance investigation, it is shown that the higher geothermal energy mass flux and inlet temperature are in favor of the larger Net Power Output for both cycles. The thermodynamic evaluation shows that the proposed parallel dual-pressure Kalina cycle exhibits a more excellent performance in terms of Net Power Output and exergy efficiency than basic Kalina cycle.

  • thermodynamic analysis of a biomass fired kalina cycle with regenerative heater
    Energy, 2014
    Co-Authors: Liyan Cao, Jiangfeng Wang, Yiping Dai
    Abstract:

    Abstract The biomass fuel is a renewable energy resource, which is viewed as a promising alternative to fossil energy. This paper investigates a biomass-fired Kalina cycle with a regenerative heater which is generally utilized to heat the feedwater and to increase the efficiency in coal-fired steam Power plant. The mathematical model of the biomass-fired Kalina cycle with a regenerative heater is established to conduct numerical simulation. A parametric analysis is conducted to examine the effects of some key thermodynamic parameters on the system performance. Furthermore, a parametric optimization is carried out by geNetic algorithm to obtain the optimum performance of system. The results demonstrate that there exists an optimum extraction pressure and its corresponding maximum fraction of flow extracted from turbine to maximize the Net Power Output and system efficiency. In addition, a higher turbine inlet pressure or turbine inlet temperature leads to higher Net Power Output and system efficiency. And Net Power Output and system efficiency increases as separator temperature rises. The optimization result of the biomass-fired Kalina cycle with/without regenerative heater indicates the system is more efficient when regenerative heater is added.

  • thermodynamic analysis and optimization of a transcritical co2 geothermal Power generation system based on the cold energy utilization of lng
    Applied Thermal Engineering, 2014
    Co-Authors: Jianyong Wang, Jiangfeng Wang, Pan Zhao
    Abstract:

    Abstract This paper investigates a transcritical CO2 cycle using geothermal resources to generate electricity. Liquefied natural gas (LNG) is employed as heat sink to drop the CO2 turbine back pressure sharply. The mathematical model of the transcritical CO2 geothermal Power generation system is established for system simulations under steady-state conditions. A parametric analysis is conducted to evaluate the effect of several key thermodynamic parameters on system performance. Additionally, a multi-objective optimization using NSGA-II method is carried out to find the optimum performance of system from both thermodynamic and economic aspects. The results show that there is an optimal CO2 turbine inlet pressure that yields the maximum exergy efficiency. A higher CO2 turbine inlet temperature or a lower CO2 turbine back pressure brings about a higher exergy efficiency. In addition, an optimal CO2 turbine inlet pressure obtains the minimum required heat exchange area per Net Power Output. The lower the CO2 turbine inlet temperature or the CO2 turbine back pressure is, the smaller the required heat exchange area per Net Power Output is. By the multi-objective optimization, a Pareto optimal solution is obtained, which shows that an increase in exergy efficiency would increase the required heat exchange area per Net Power Output.

  • thermo economic analysis and comparison of a co2 transcritical Power cycle and an organic rankine cycle
    Geothermics, 2014
    Co-Authors: Maoqing Li, Jiangfeng Wang, Saili Li, Xurong Wang, Weifeng He
    Abstract:

    Abstract CO 2 transcritical Power cycle (CDTPC) and organic Rankine cycle (ORC) can effectively recover low grade heat due to their excellent thermodynamic performance. This paper conducts thermo-economic analysis and comparison of a CDTPC and an ORC using R123, R245fa, R600a and R601 as the working fluids driven by the low temperature geothermal source with the temperature ranging from 90 °C to 120 °C. The two Power cycles are evaluated in terms of five indicators: Net Power Output, thermal efficiency, exergy efficiency, cost per Net Power Output (CPP) and the ratio of the heat exchangers’ cost to the overall system's cost (ROC). Results indicate that the regenerator can increase the thermodynamic performance of the two Power cycles. The ORC working with R600a presents the highest Net Power Output while the highest thermal and exergy efficiencies are obtained by the regenerative ORC working with R601. The maximum Net Power Output of the regenerative CDTPC is slightly higher than that of the basic CDTPC. The CDTPC has a better economic performance than ORC in terms of CPP and under a certain turbine inlet pressure the CPP of the regenerative CDTPC is even lower than that of the basic CDTPC.

  • Thermodynamic analysis and optimization of an (organic Rankine cycle) ORC using low grade heat source
    Energy, 2013
    Co-Authors: Jiangfeng Wang, Man Wang, Shaolin Ma
    Abstract:

    Organic Rankine cycle can effectively recover the low grade heat source due to its distinctive thermodynamic performance. Based on the thermodynamic mathematical models of an ORC (organic Rankine cycle) system, this study examines the effects of key thermodynamic design parameters, including turbine inlet pressure, turbine inlet temperature, pinch temperature difference and approach temperature difference in (heat recovery vapor generator) HRVG, on the Net Power Output and surface areas of both the HRVG and the condenser using R123, R245fa and isobutane. Considering the economic factor for the system optimization design, a ratio of Net Power Output to total heat transfer area is selected as the performance evaluation criterion to predict the system performance from the view of both thermodynamics and economics. GeNetic algorithm is employed to optimize the system performance. The results show that turbine inlet pressure, turbine inlet temperature, pinch temperature difference and approach temperature difference have significant effects on the Net Power Output and surface areas of both the HRVG and the condenser. By parametric optimization, the ORC system with isobutane has the best system performance than that with R123 or R245fa. The optimum pinch temperature difference and approach temperature difference are generally located at upper boundary over their parametric design ranges.

Minhsiung Yang - One of the best experts on this subject based on the ideXlab platform.

  • Economic research of the transcritical Rankine cycle systems to recover waste heat from the marine medium-speed diesel engine
    Applied Thermal Engineering, 2017
    Co-Authors: Minhsiung Yang, Rong-hua Yeh
    Abstract:

    Abstract The aim of this study is to investigate the economic performance of a transcritical Rankine cycle (TRC) system for recovering waste heat from the exhaust gas of a marine medium-speed diesel engine. The variation of Net Power Output, total cost of equipments and exergy destruction are investigated for the TRC system. Furthermore, to evaluate the economic performance of energy utilization, a parameter, Net Power Output index, which is the ratio of Net Power Output to the total cost, is introduced of the TRC system using R125, R143a, R218 and R1234yf as working fluids. The results show that R1234yf performs the highest economic performance, followed by R143a, R125 and R218 of the TRC system. It reveals that R1234yf not only has the smallest high and low pressures of the TRC system for reducing the purchased cost of equipments, but also promotes a larger pressure ratio of the expander for generating Power Output among these working fluids. The comparisons of optimal pressure ratios obtained from thermodynamic and economic optimizations for these working fluids in the TRC system are also reported. In addition, an evaluation method using thermal efficiency and operating pressure ratio as parameters is proposed to assess the suitability of the working fluids of TRC system in economic analysis for waste heat recovery from the exhaust gas of a diesel engine.

  • economic performances optimization of an organic rankine cycle system with lower global warming potential working fluids in geothermal application
    Renewable Energy, 2016
    Co-Authors: Minhsiung Yang
    Abstract:

    The aim of this study is to investigate the economic optimization for an ORC system utilizing the geothermal energy. An economic parameter of Net Power Output index, which is the ratio of Net Power Output to the total cost, is proposed to optimize the ORC system using zero ODP and lower GWP working fluids. The maximum Net Power Output index is obtained and the corresponding optimal pinch point temperature differences of heat exchangers are also evaluated for the ORC system. Furthermore, the analyses of the corresponding operating temperatures and pressures on the optimal economic performances of the ORC system are carried out. The effects of turbine inlet temperatures and their corresponding optimization are also discussed. The results show that R600 performs the most satisfactorily followed by R600a, R1233zd, R1234yf, R1234ze, and R290 under economic performance optimization. Moreover, the pinch point temperature differences in the evaporator vary more significantly than those in the condenser in optimal economic evaluations. The ORC system operated with R600, R600a, and R1233zd would have reductions in the proportion of equipment purchased cost from large to small attributed to lower operating pressures.

  • Economic performances optimization of the transcritical Rankine cycle systems in geothermal application
    Energy Conversion and Management, 2015
    Co-Authors: Minhsiung Yang, Rong-hua Yeh
    Abstract:

    The aim of this study is to investigate the economic optimization of a TRC system for the application of geothermal energy. An economic parameter of Net Power Output index, which is the ratio of Net Power Output to the total cost, is applied to optimize the TRC system using CO2, R41 and R125 as working fluids. The maximum Net Power Output index and the corresponding optimal operating pressures are obtained and evaluated for the TRC system. Furthermore, the analyses of the corresponding averaged temperature differences in the heat exchangers on the optimal economic performances of the TRC system are carried out. The effects of geothermal temperatures on the thermodynamic and economic optimizations are also revealed. In both optimal economic and thermodynamic evaluations, R125 performs the most satisfactorily, followed by R41 and CO2 in the TRC system. In addition, the TRC system operated with CO2 has the largest averaged temperature difference in the heat exchangers and thus has potential in future application for lower-temperature heat resources. The highest working pressures obtained from economic optimization are always lower than those from thermodynamic optimization for CO2, R41, and R125 in the TRC system.

Rong-hua Yeh - One of the best experts on this subject based on the ideXlab platform.

  • Economic research of the transcritical Rankine cycle systems to recover waste heat from the marine medium-speed diesel engine
    Applied Thermal Engineering, 2017
    Co-Authors: Minhsiung Yang, Rong-hua Yeh
    Abstract:

    Abstract The aim of this study is to investigate the economic performance of a transcritical Rankine cycle (TRC) system for recovering waste heat from the exhaust gas of a marine medium-speed diesel engine. The variation of Net Power Output, total cost of equipments and exergy destruction are investigated for the TRC system. Furthermore, to evaluate the economic performance of energy utilization, a parameter, Net Power Output index, which is the ratio of Net Power Output to the total cost, is introduced of the TRC system using R125, R143a, R218 and R1234yf as working fluids. The results show that R1234yf performs the highest economic performance, followed by R143a, R125 and R218 of the TRC system. It reveals that R1234yf not only has the smallest high and low pressures of the TRC system for reducing the purchased cost of equipments, but also promotes a larger pressure ratio of the expander for generating Power Output among these working fluids. The comparisons of optimal pressure ratios obtained from thermodynamic and economic optimizations for these working fluids in the TRC system are also reported. In addition, an evaluation method using thermal efficiency and operating pressure ratio as parameters is proposed to assess the suitability of the working fluids of TRC system in economic analysis for waste heat recovery from the exhaust gas of a diesel engine.

  • Economic performances optimization of the transcritical Rankine cycle systems in geothermal application
    Energy Conversion and Management, 2015
    Co-Authors: Minhsiung Yang, Rong-hua Yeh
    Abstract:

    The aim of this study is to investigate the economic optimization of a TRC system for the application of geothermal energy. An economic parameter of Net Power Output index, which is the ratio of Net Power Output to the total cost, is applied to optimize the TRC system using CO2, R41 and R125 as working fluids. The maximum Net Power Output index and the corresponding optimal operating pressures are obtained and evaluated for the TRC system. Furthermore, the analyses of the corresponding averaged temperature differences in the heat exchangers on the optimal economic performances of the TRC system are carried out. The effects of geothermal temperatures on the thermodynamic and economic optimizations are also revealed. In both optimal economic and thermodynamic evaluations, R125 performs the most satisfactorily, followed by R41 and CO2 in the TRC system. In addition, the TRC system operated with CO2 has the largest averaged temperature difference in the heat exchangers and thus has potential in future application for lower-temperature heat resources. The highest working pressures obtained from economic optimization are always lower than those from thermodynamic optimization for CO2, R41, and R125 in the TRC system.

Christian Vetter - One of the best experts on this subject based on the ideXlab platform.

  • comparison of sub and supercritical organic rankine cycles for Power generation from low temperature low enthalpy geothermal wells considering specific Net Power Output and efficiency
    Applied Thermal Engineering, 2013
    Co-Authors: Christian Vetter, Hans Joachim Wiemer, Dietmar Kuhn
    Abstract:

    Abstract Electrical Power production at low-enthalpy (∼150 °C) geothermal sites is usually realized using an Organic Rankine Cycle (ORC process). This paper presents our analysis of sub- and supercritical processes using propane, carbon dioxide and ten other refrigerants as working fluids. The impact of crucial indicators for optimization, such as specific Net Power, thermal efficiency and heat input is discussed in detail. The focus was to optimize the thermodynamic loop and the influence of other parameters, such as condensing temperature, minimal temperature difference in the heat exchanger, and internal heat recovery. Simulations showed that at a geothermal fluid temperature of 150 °C, a suitable working fluid such as propane or R143a can increase specific Net Power Output up to 40%. Furthermore, systematic simulations on brine temperatures of 130–170 °C from subcritical to supercritical operation are discussed. Results from this research may also be applicable for electricity generation using waste heat from combined heat and Power (CHP) plants or other technical processes.

  • Comparison of sub- and supercritical Organic Rankine Cycles for Power generation from low-temperature/low-enthalpy geothermal wells, considering specific Net Power Output and efficiency
    Applied Thermal Engineering, 2012
    Co-Authors: Christian Vetter, Hans Joachim Wiemer, Dietmar Kuhn
    Abstract:

    Abstract Electrical Power production at low-enthalpy (∼150 °C) geothermal sites is usually realized using an Organic Rankine Cycle (ORC process). This paper presents our analysis of sub- and supercritical processes using propane, carbon dioxide and ten other refrigerants as working fluids. The impact of crucial indicators for optimization, such as specific Net Power, thermal efficiency and heat input is discussed in detail. The focus was to optimize the thermodynamic loop and the influence of other parameters, such as condensing temperature, minimal temperature difference in the heat exchanger, and internal heat recovery. Simulations showed that at a geothermal fluid temperature of 150 °C, a suitable working fluid such as propane or R143a can increase specific Net Power Output up to 40%. Furthermore, systematic simulations on brine temperatures of 130–170 °C from subcritical to supercritical operation are discussed. Results from this research may also be applicable for electricity generation using waste heat from combined heat and Power (CHP) plants or other technical processes.