In this paper,an ejector enhanced two-stage auto-cascade refrigeration cycle(EARC)using ternary mixture R600a/R32/R1150 is proposed for application of-80℃freezing.In EARC cycle,an ejector was employed to recover the ...In this paper,an ejector enhanced two-stage auto-cascade refrigeration cycle(EARC)using ternary mixture R600a/R32/R1150 is proposed for application of-80℃freezing.In EARC cycle,an ejector was employed to recover the expansion work in the throttling processes and lifted the suction pressure of the compressor.The performances of the ejector enhanced two-stage auto-cascade refrigeration cycle and conventional auto-cascade refrigeration cycle(CARC)were compared using thermodynamic analysis methods.The influences of the important operation parameters including mass fraction ratio of the mixture,fluid quality at the second separator inlet,condensation temperature,evaporation temperature,and expansion ratio of expansion valve on the performances of EARC cycle were discussed in detail.The results indicate that ternary mixture R600a/R32/R1150 has the optimal mass fraction ratio of 0.45/0.2/0.35 with respect to the maximum COP.The EARC cycle yields higher performance than the CARC cycle in terms of COP,exergy efficiency and volumetric refrigeration capacity.And 4.9%-36.5%improvement in COP and 6.9%-34.3%higher exergy efficiency could be obtained in EARC cycle comparing with CARC cycle.The finding of this study suggests that the EARC cycle has a promising application potential for low temperature freezing.展开更多
为了提高制冷系统性能,提出了一种双喷射压缩耦合制冷系统,建立了系统模型,以R1234ze为制冷剂,应用Fortran软件对系统进行了模拟计算分析,并与气气喷射压缩耦合制冷系统进行对比。结果表明:随着中间温度的升高,机械性能系数(coefficient...为了提高制冷系统性能,提出了一种双喷射压缩耦合制冷系统,建立了系统模型,以R1234ze为制冷剂,应用Fortran软件对系统进行了模拟计算分析,并与气气喷射压缩耦合制冷系统进行对比。结果表明:随着中间温度的升高,机械性能系数(coefficient of mechanical performance,COPm)呈现先增大后减小的变化趋势,[火用]效率呈现增大的趋势;随着冷凝温度的升高,COPm和[火用]效率都呈现减小的趋势;随着蒸发温度的升高,COPm增大,[火用]效率减小。随着发生温度的升高,COPm和[火用]效率都呈现增大的趋势。与气气喷射压缩耦合制冷系统相比,双喷射压缩耦合制冷系统性能更好。且适当优化中间温度,减少冷凝器、蒸发器、气气喷射器的[火用]损,可以更大程度地节能减排。展开更多
基金financially supported by National Natural Science Foundation of China(NSFC)under the grant No.51806160China Postdoctoral Science Foundation(CPSF)under the grant No.2018M640982.
文摘In this paper,an ejector enhanced two-stage auto-cascade refrigeration cycle(EARC)using ternary mixture R600a/R32/R1150 is proposed for application of-80℃freezing.In EARC cycle,an ejector was employed to recover the expansion work in the throttling processes and lifted the suction pressure of the compressor.The performances of the ejector enhanced two-stage auto-cascade refrigeration cycle and conventional auto-cascade refrigeration cycle(CARC)were compared using thermodynamic analysis methods.The influences of the important operation parameters including mass fraction ratio of the mixture,fluid quality at the second separator inlet,condensation temperature,evaporation temperature,and expansion ratio of expansion valve on the performances of EARC cycle were discussed in detail.The results indicate that ternary mixture R600a/R32/R1150 has the optimal mass fraction ratio of 0.45/0.2/0.35 with respect to the maximum COP.The EARC cycle yields higher performance than the CARC cycle in terms of COP,exergy efficiency and volumetric refrigeration capacity.And 4.9%-36.5%improvement in COP and 6.9%-34.3%higher exergy efficiency could be obtained in EARC cycle comparing with CARC cycle.The finding of this study suggests that the EARC cycle has a promising application potential for low temperature freezing.
文摘为了提高制冷系统性能,提出了一种双喷射压缩耦合制冷系统,建立了系统模型,以R1234ze为制冷剂,应用Fortran软件对系统进行了模拟计算分析,并与气气喷射压缩耦合制冷系统进行对比。结果表明:随着中间温度的升高,机械性能系数(coefficient of mechanical performance,COPm)呈现先增大后减小的变化趋势,[火用]效率呈现增大的趋势;随着冷凝温度的升高,COPm和[火用]效率都呈现减小的趋势;随着蒸发温度的升高,COPm增大,[火用]效率减小。随着发生温度的升高,COPm和[火用]效率都呈现增大的趋势。与气气喷射压缩耦合制冷系统相比,双喷射压缩耦合制冷系统性能更好。且适当优化中间温度,减少冷凝器、蒸发器、气气喷射器的[火用]损,可以更大程度地节能减排。
