The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Xinrong Zhang - One of the best experts on this subject based on the ideXlab platform.
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a brief review study of various Thermodynamic Cycles for high temperature power generation systems
Energy Conversion and Management, 2015Co-Authors: Sicong Yu, Lin Chen, Yan Zhao, Hongxu Li, Xinrong ZhangAbstract:Abstract This paper presents a review of the previous studies and papers about various Thermodynamic Cycles working for high temperature power generation procedures, in these Cycles the highest temperature is not lower than 700 K. Thermodynamic Cycles that working for power generation are divided into two broad categories, Thermodynamic Cycle model study and working fluid analysis. Thermodynamic Cycle contains the simple Cycle model and the complex Cycle model, emphasis has been given on the complex Thermodynamic Cycles due to their high thermal efficiencies. Working fluids used for high temperature Thermodynamic Cycles is a dense gas rather than a liquid. A suitable Thermodynamic Cycle is crucial for effectively power generation especially under the condition of high temperature. The main purpose is to find out the characteristics of various Thermodynamic Cycles when they are working in the high temperature region for power generation. As this study shows, combined Cycles with both renewable and nonrenewable energies as the heat source can show good performance.
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theoretical analysis of a Thermodynamic Cycle for power and heat production using supercritical carbon dioxide
Energy, 2007Co-Authors: Xinrong Zhang, Hiroshi Yamaguchi, Katsumi Fujima, Masatoshi Enomoto, N SawadaAbstract:A numerical study of a Thermodynamic Cycle is described: solar energy powered Rankine Cycle using supercritical carbon dioxide as the working fluid for combined power and heat production. A model is developed to predict the Cycle performance. Experimental data is used to verify the numerical formulation. Of interest in the present study is the Thermodynamic Cycle of 0.3–1.0kW power generation and 1.0–3.0kW heat output. The effects of the governing parameters on the performance are investigated numerically. The results show that the Cycle has a power generation efficiency of somewhat above 20.0% and heat recovery efficiency of 68.0%, respectively. It is seen that the Cycle performance is strongly dependent on the governing parameters and they can be optimized to provide maximum power, maximum heat recovery or a combination of both. The power generation and heat recovery are found to be increased with solar collector efficient area. The power generation is also increased with water temperature of the heat recovery system, but decreased with heat exchanging area. It is also seen that the effect of the water flow rate in the heat recovery system on the Cycle performance is negligible.
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analysis of a novel solar energy powered rankine Cycle for combined power and heat generation using supercritical carbon dioxide
Renewable Energy, 2006Co-Authors: Xinrong Zhang, Hiroshi Yamaguchi, Katsumi Fujima, Masatoshi Enomoto, Daisuke Uneno, N SawadaAbstract: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 CO2-based Rankine Cycle were theoretically investigated and the effects of various design conditions, namely, solar radiation, solar collector area and CO2 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 CO2 flow rate. The estimated COPpower and COPheat increase with the CO2 flow rate, but decrease with the collector area. The CO2-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.
N Sawada - One of the best experts on this subject based on the ideXlab platform.
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theoretical analysis of a Thermodynamic Cycle for power and heat production using supercritical carbon dioxide
Energy, 2007Co-Authors: Xinrong Zhang, Hiroshi Yamaguchi, Katsumi Fujima, Masatoshi Enomoto, N SawadaAbstract:A numerical study of a Thermodynamic Cycle is described: solar energy powered Rankine Cycle using supercritical carbon dioxide as the working fluid for combined power and heat production. A model is developed to predict the Cycle performance. Experimental data is used to verify the numerical formulation. Of interest in the present study is the Thermodynamic Cycle of 0.3–1.0kW power generation and 1.0–3.0kW heat output. The effects of the governing parameters on the performance are investigated numerically. The results show that the Cycle has a power generation efficiency of somewhat above 20.0% and heat recovery efficiency of 68.0%, respectively. It is seen that the Cycle performance is strongly dependent on the governing parameters and they can be optimized to provide maximum power, maximum heat recovery or a combination of both. The power generation and heat recovery are found to be increased with solar collector efficient area. The power generation is also increased with water temperature of the heat recovery system, but decreased with heat exchanging area. It is also seen that the effect of the water flow rate in the heat recovery system on the Cycle performance is negligible.
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analysis of a novel solar energy powered rankine Cycle for combined power and heat generation using supercritical carbon dioxide
Renewable Energy, 2006Co-Authors: Xinrong Zhang, Hiroshi Yamaguchi, Katsumi Fujima, Masatoshi Enomoto, Daisuke Uneno, N SawadaAbstract: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 CO2-based Rankine Cycle were theoretically investigated and the effects of various design conditions, namely, solar radiation, solar collector area and CO2 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 CO2 flow rate. The estimated COPpower and COPheat increase with the CO2 flow rate, but decrease with the collector area. The CO2-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.
J. Rijpkema - One of the best experts on this subject based on the ideXlab platform.
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Waste Heat Recovery in Heavy Duty Diesel Engines
2018Co-Authors: J. RijpkemaAbstract:Over 50% of the energy released by burning fuel in a truck engine is lost as heat rather than being used to propel the vehicle. A promising method for capturing and reusing this heat, and thereby improving engine efficiency, is to exploit Thermodynamic Cycles for waste heat recovery (WHR). The goal of this thesis is to evaluate the Thermodynamic performance of multiple Thermodynamic Cycles using many different working fluids, considering all relevant low- and high-temperature heat sources available in a heavy duty Diesel engine to be able to identify the best possible combination of heat source, working fluid and Thermodynamic Cycle. To evaluate the potential of each heat source, the operating conditions of a real heavy duty Diesel engine were used to define boundary conditions. A GT-Power model of such an engine was previously developed and experimentally validated for the stationary points of the European stationary Cycle (ESC). Using the results from this model, an energy and exergy analysis was performed, which revealed four heat sources with the potential for waste heat recovery: the charge air cooler (CAC), the coolant flow, the exhaust gas recirculation cooler (EGRC), and the exhaust flow. Modelica models were developed for four different Thermodynamic Cycles: the organic Rankine Cycle (ORC), the transcritical Rankine Cycle (TRC), the trilateral flash Cycle (TFC), and the organic flash Cycle (OFC). Simulations with different boundary conditions, constraints, and engine operating conditions showed that variation in these conditions significantly affected the results obtained. In general, the best WHR performance was achieved when the thermal profiles of heat source and the chosen Thermodynamic Cycle were closely matched. Using realistic constraints and boundary conditions, the ORC gave the best performance with acetone, cyclopentane, or methanol as the working fluid. However, taking flammability and toxicity into account, the best-performing fluids were R1233zd(E), MM, and Novec649.
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Thermodynamic Cycle and Working Fluid Selection for Waste Heat Recovery in a Heavy Duty Diesel Engine
SAE International journal of engines, 2018Co-Authors: J. Rijpkema, S B Andersson, Karin MunchAbstract:Thermodynamic power Cycles have been shown to provide an excellent method for waste heat recovery (WHR) in internal combustion engines. By capturing and reusing heat that would otherwise be lost to the environment, the efficiency of engines can be increased. This study evaluates the maximum power output of different Cycles used for WHR in a heavy duty Diesel engine with a focus on working fluid selection. Typically, only high temperature heat sources are evaluated for WHR in engines, whereas this study also considers the potential of WHR from the coolant. To recover the heat, four types of power Cycles were evaluated: the organic Rankine Cycle (ORC), transcritical Rankine Cycle, trilateral flash Cycle, and organic flash Cycle. This paper allows for a direct comparison of these Cycles by simulating all Cycles using the same boundary conditions and working fluids. To identify the best performing Cycle, a large number of working fluids were evaluated with regards to the maximum power output of the power Cycle for each heat source. Taking into account the constraints and boundary conditions, this study shows that the ORC gives the best performance with a power output of around 1.5 kW for the coolant, 2.5 kW for the exhaust gas recirculation cooler, and 5 kW for the exhaust with acetone, cyclopentane and methanol as the best performing working fluids.
D Y Goswami - One of the best experts on this subject based on the ideXlab platform.
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optimum operating conditions for a combined power and cooling Thermodynamic Cycle
Applied Energy, 2007Co-Authors: S M Sadrameli, D Y GoswamiAbstract:The combined production of thermal power and cooling with an ammonia-water based Cycle proposed by Goswami is under intensive investigation. In the Cycle under consideration, simultaneous cooling output is produced by expanding an ammonia-rich vapor in an expander to sub-ambient temperatures and subsequently heating the cool exhaust. When this mechanism for cooling production is considered in detail, it is apparent that the cooling comes at some expense to work production. To optimize this trade-off, a very specific coefficient-of-performance has been defined. In this paper, the simulation of the Cycle was carried out in the process simulator ASPEN Plus. The optimum operating conditions have been found by using the Equation Oriented mode of the simulator and some of the results have been compared with the experimental data obtained from the Cycle. The agreement between the two sets proves the accuracy of the optimization results.
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effectiveness of cooling production with a combined power and cooling Thermodynamic Cycle
Applied Thermal Engineering, 2006Co-Authors: C Martin, D Y GoswamiAbstract:Abstract The combined production of power and cooling with an ammonia–water based Cycle is under investigation. Cooling is produced by expanding an ammonia-rich vapor in an expander to sub-ambient temperatures and it is shown that a compromise exists between cooling and work production. A new parameter, termed the effective COP, is used to relate the gain in cooling to the compromise in work production. When the parameter is used to optimize conditions for the rectifier, the effective COP values are good, having values of up to 5. However, when combined operation is compared to work-optimized results, the maximum effective COP values are near 1.1. This implies that per unit of cooling production, nearly equal amounts of work are compromised for combined operation.
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exergy analysis of a combined power and refrigeration Thermodynamic Cycle driven by a solar heat source
Journal of Solar Energy Engineering-transactions of The Asme, 2003Co-Authors: Afif Hasan, D Y GoswamiAbstract:Exergy Thermodynamics is employed to analyze a binary ammonia water mixture Thermodynamic Cycle that produces both power and refrigeration. The analysis includes exergy destruction for each component in the Cycle as well as the first law and exergy efficiencies of the Cycle. The optimum operating conditions are established by maximizing the Cycle exergy efficiency for the case of a solar heat source. Performance of the Cycle over a range of heat source temperatures of 320-460°K was investigated. It is found that increasing the heat source temperature does not necessarily produce higher exergy efficiency, as is the case for first law efficiency. The largest exergy destruction occurs in the absorber, while little exergy destruction takes place in the boiler.
Karin Munch - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic Cycle and Working Fluid Selection for Waste Heat Recovery in a Heavy Duty Diesel Engine
SAE International journal of engines, 2018Co-Authors: J. Rijpkema, S B Andersson, Karin MunchAbstract:Thermodynamic power Cycles have been shown to provide an excellent method for waste heat recovery (WHR) in internal combustion engines. By capturing and reusing heat that would otherwise be lost to the environment, the efficiency of engines can be increased. This study evaluates the maximum power output of different Cycles used for WHR in a heavy duty Diesel engine with a focus on working fluid selection. Typically, only high temperature heat sources are evaluated for WHR in engines, whereas this study also considers the potential of WHR from the coolant. To recover the heat, four types of power Cycles were evaluated: the organic Rankine Cycle (ORC), transcritical Rankine Cycle, trilateral flash Cycle, and organic flash Cycle. This paper allows for a direct comparison of these Cycles by simulating all Cycles using the same boundary conditions and working fluids. To identify the best performing Cycle, a large number of working fluids were evaluated with regards to the maximum power output of the power Cycle for each heat source. Taking into account the constraints and boundary conditions, this study shows that the ORC gives the best performance with a power output of around 1.5 kW for the coolant, 2.5 kW for the exhaust gas recirculation cooler, and 5 kW for the exhaust with acetone, cyclopentane and methanol as the best performing working fluids.
