Organic Rankine cycle(ORC)is widely used for the low grade geothermal power generation.However,a large amount of irreversible loss results in poor technical and economic performance due to its poor matching between th...Organic Rankine cycle(ORC)is widely used for the low grade geothermal power generation.However,a large amount of irreversible loss results in poor technical and economic performance due to its poor matching between the heat source/sink and the working medium in the condenser and the evaporator.The condensing temperature,cooling water temperature difference and pinch point temperature difference are often fixed according to engineering experience.In order to optimize the ORC system comprehensively,the coupling effect of evaporation and condensation process was proposed in this paper.Based on the laws of thermodynamics,the energy analysis,exergy analysis and entropy analysis were adopted to investigate the ORC performance including net output power,thermal efficiency,exergy efficiency,thermal conductivity,irreversible loss,etc.,using geothermal water at a temperature of 120℃as the heat source and isobutane as the working fluid.The results show that there exists a pair of optimal evaporating temperature and condensing temperatures to maximize the system performance.The net power output and the system comprehensive performance achieve their highest values at the same evaporating temperature,but the system comprehensive performance corresponds to a lower condensing temperature than the net power output.展开更多
A two-dimensional steady state model was developed and solved numerically to predict the performance of evaporative condensing regenerator.Two-dimensional parameter distributions of air,solution and refrigerant were c...A two-dimensional steady state model was developed and solved numerically to predict the performance of evaporative condensing regenerator.Two-dimensional parameter distributions of air,solution and refrigerant were calculated by the mathematical model.The solution content first increases and then decreases along the solution flow direction.At y/Hr=0.98(where Hr is the height of regenerator),air humidity increases from 1.99% to 2.348% firstly and then decreases.The experimental results were used to validate mathematical model.It is indicated that the simulation results agree with experimental data well.The results not only show that the mathematical model can be used to predict the performance of regenerator,but also has great value in the design and improvement of evaporative condensing regenerator.展开更多
基金Project(2018YFB1501805)supported by the National Key Research and Development Program of ChinaProject(51406130)supported by the National Natural Science Foundation of ChinaProject(201604-504)supported by the Key Laboratory of Efficient Utilization of Low and Medium Grade Energy(Tianjin University),China
文摘Organic Rankine cycle(ORC)is widely used for the low grade geothermal power generation.However,a large amount of irreversible loss results in poor technical and economic performance due to its poor matching between the heat source/sink and the working medium in the condenser and the evaporator.The condensing temperature,cooling water temperature difference and pinch point temperature difference are often fixed according to engineering experience.In order to optimize the ORC system comprehensively,the coupling effect of evaporation and condensation process was proposed in this paper.Based on the laws of thermodynamics,the energy analysis,exergy analysis and entropy analysis were adopted to investigate the ORC performance including net output power,thermal efficiency,exergy efficiency,thermal conductivity,irreversible loss,etc.,using geothermal water at a temperature of 120℃as the heat source and isobutane as the working fluid.The results show that there exists a pair of optimal evaporating temperature and condensing temperatures to maximize the system performance.The net power output and the system comprehensive performance achieve their highest values at the same evaporating temperature,but the system comprehensive performance corresponds to a lower condensing temperature than the net power output.
基金Project(PHR201007127) supported by Academic Human Resources Development Fund of Institutions of Higher Learning under the Jurisdiction of Beijing Municipality, China Project(bsbe2010-05) supported by the Opening Funds of State Key Laboratory of Building Safety and Built Environment, China Project supported by the Doctoral Startup Foundation of Beijing University of Civil Engineering and Architecture, China
文摘A two-dimensional steady state model was developed and solved numerically to predict the performance of evaporative condensing regenerator.Two-dimensional parameter distributions of air,solution and refrigerant were calculated by the mathematical model.The solution content first increases and then decreases along the solution flow direction.At y/Hr=0.98(where Hr is the height of regenerator),air humidity increases from 1.99% to 2.348% firstly and then decreases.The experimental results were used to validate mathematical model.It is indicated that the simulation results agree with experimental data well.The results not only show that the mathematical model can be used to predict the performance of regenerator,but also has great value in the design and improvement of evaporative condensing regenerator.
