中温地热能驱动的跨临界有机朗肯-蒸气压缩制冷系统的火用分析

建立中温地热能驱动跨临界有机朗肯?蒸气压缩制冷系统的火用分析热力学模型，采用R143a作为系统循环工质，探讨膨胀机入口压力、地热流体进口温度、冷凝温度、蒸发温度对火用效率的影响规律，分析系统各个部件的火用损失。计算结果表明：合理的膨胀机入口压力应该小于1.8倍临界压力；存在最佳的地热流体进口温度使得系统的火用效率最大；降低冷凝温度和提高蒸发温度都可以提高?效率，但需要增加换热器等效换热面积作为代价；冷凝器、发生器、膨胀机、节流阀、压缩机、蒸发器、工质泵的火用损失依次降低；随着地热流体进口温度升高，冷凝器及发生器的火用损失所占的比例增大，其它部件的火用损失对应的比例则降低。本文可以为跨临界有机朗肯?蒸气压缩制冷系统的设计提供依据。

Exergy Analysis of Transcritical Organic Rankine-Vapor Compression Refrigiration System Powered by Medium-grade Geothermal Energy

A thermodynamic exergy analysis model of the transcritical Organic Rankine-Vapor Compression refrigeration system powered by medium-grade geothermal energy is set up. R143a is selected as working fluid. The influence rules of expander inlet pressure, geothermal fluid inlet temperature, condensing temperature and evaporating temperature on the exergy efficiency are studied. What’s more, each component exergy loss of the system is analyzed. The calculation results showed that reasonable expander inlet pressure should be less than 1.8 times the critical pressure. There exists an optimal geothermal fluid inlet temperature for exergy efficiency. A lower condensing temperature and higher evaporating temperature could improve exergy efficiency, which need more equivalent heat transfer area. The absolute exergy loss of condenser, generator, expander and throttle valve, compressor, evaporator decrease in turn. As the geothermal fluid inlet temperature increases, exergy loss ratio of condenser and generator increases, while that of the other parts decrease. This work could provide references for the design of transcritical Organic Rankine-Vapor Compression refrigeration system.