Study On The Performance Of Organic Flash Rankine Cycle Using Zeotropic Working Fluid Based On Liquid-Separated Condensation

Traditional thermodynamic cycles have low utilization efficiency of heat energy.Organic flash-Rankine cycle（OFRC）combines the advantages of flash cycle and Rankine cycle,and uses zeotropic mixture as working fluid,which can efficiently utilize the meddle-low temperature clean energy.The conclusions are as follows:（1）The thermal performance of OFRC system increases with the increase of heat source temperature.In the heat source temperature range of 140-200℃,the components with the best thermal performance of OFRC are all zeotropic working fluid.The net power output of OFRC increased by 12.05%,19.12%,16.71%and 14.86%compared to the pure working fluid R600.And the maximum thermal efficiency increased by 7.30%,9.39%,6.65%and 7.53%.The changes of exergy efficiency and exergy recovery efficiency of OFRC were consistent with the thermal efficiency and net power output respectively.（2）Different molar fraction of zeotropic working fluid can produce different effects by adopted liquid-separated condensation.When the heat source temperature was 120℃and the R600 molar fraction was 0.1,0.2 and 0.3,the thermal performance of OFRC would deteriorate by adopted liquid-separated condensation.And the net power output decreased by 14.33%,8.41%and 0.88%,respectively.The thermal efficiency decreased by 11.94%,6.97%and 0.58%.When the molar fraction of R600was 0,0.4-0.9 and 1,the thermal performance of OFRC would not be affected by adopted liquid-separated condensation.（3）The economic performance of OFRC will deteriorate when zeotropic working fliud is used.When the heat source temperature was 100-200℃,the specific power area of OFRC increased by 41.62%,49.12%,39.83%,50.85%,62.00%and 65.92%compared to that of R600,respectively,SIC increased by 3.57%,30.50%,1.76%,0.49%,0.63%and 0.87%.And when the heat source temperature was 100℃and120℃,the EGC of OFRC increased by 2.98%and 2.33%.（4）The heat transfer area of OFRC will be reduced and the economic performnce will be improved.When the heat source temperature was 120℃and the R600 molar fraction was 0.1 and 0.2,the liquid-separated dryness corresponding to the minimum condenser area was 0.1.And when the R600 molar fraction was 0 and 0.3-1,the liquid-separated dryness was 0.3.Under the dryness,the specific power area of OFRC decreased by 27.54%,the SIC of OFRC was reduced by 1.78%,and EGC was reduced by 3.33%compared to that without liquid-separated condensation,respectively.（5）0.1 and 0.4 are selected to be as the representative components of R600.When G_wf is small,the effect of liquid-separated condensation will be better,but the heat transfer area of OFRC will increase.The effect of liquid-separated condensation is affected by T_r,V_cond and D_in,cond,and has different performance under different R600molar fraction.In general,smaller T_r,larger G_wf,V_cond and D_in,cond can lead to better economic performance of OFRC.