In order to solve the problem of large difference in thermodynamic performance of geothermal dual cycle power generation system with different working fluid,EES software was used to analyze the 1 MW regenerative geothermal dual cycle power generation system,and the change law of thermodynamic parameters such as net generation per ton of water,net efficiency and expansion ratio of the power generation system was studied when the geothermal heat source temperature was 90～150 ℃.Through the comparison of the above parameters,the working fluid with the best comprehensive performance was obtained,and the thermodynamic performance of the dual-cycle power generation system was optimized.The results show that under constant parameters such as temperature of the cold and heat sources,there exists a maximum net power generation per ton of water in the system as the evaporation temperature of the working fluid increases.The maximum net power generation per ton of water,net efficiency,and expansion ratio of the system increase with the increase of heat source temperature,while the trend of changes in the mass flow rate of the working fluid is opposite.Under the same cold and heat source parameters,R134a has the highest power generation per ton of water,while R245fa has the highest net efficiency and expansion ratio.For example,at a heat source temperature of 110 ℃,the net power generation per ton of water using R134a is 3.035(kW·h)/t,and the net efficiency of R245fa is 6.24％,the expansion ratio is 3.146.Based on a comprehensive comparison of the thermodynamic performance parameters and physical properties of the working fluid,it is recommended to use R245fa working fluid.The research results can provide guidance for the parameter design of regenerative geothermal dual cycle power generation systems.
关键词
工程热力学/双循环回热系统/工质/系统优化/地热发电
Key words
engineering thermodynamics/dual cycle regenerative system/working fluid/system optimization/geothermal power generation
维普
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