基于有机朗肯循环的低温地热制冷系统热力学分析

为有效利用低温地热资源，本文以有机朗肯–蒸汽压缩制冷系统为研究对象，建立了系统的热力学模型，分析比较了分别以R290、R600、R600a、R601、R601a和R1270为工质时的系统性能，并以系统整体COP和每千瓦制冷量所对应的工质流量为关键指标对工质进行了优选。分析结果表明：当地热水温度为60 ~ 90℃，冷凝温度为30 ~ 55℃，蒸发温度为 –15 ~15℃时，R601是系统的最佳工质。当地热水温度为90℃，其余参数为典型工况值时，工质R601所对应的系统性能系数COP为0.49。

Thermodynamic Analysis of a Rankine Cycle Powered Refrigeration System using Low-Temperature Geothermal Energy

To efficiently utilize low-temperature geothermal energy, an organic Rankine cycle-vapor compression refrigeration (ORC-VCR) system was employed and a thermodynamic model was developed. Six working fluids of R290, R600, R600a, R601, R601a and R1270 were analyzed and evaluated in order to identify suitable working fluids which may yield high system efficiencies. The overall COP and working fluid mass flow rate of per kW cooling capacity are chosen as key performance indicators. The calculated results show that R601 is the best working fluid for the ORC-VCR system as the geothermal water temperature is between 60oC and 90oC, the condensation temperature ranges from 30oC to 55oC and the evaporation temperature varies from 30oC to 55oC. When the geothermal water temperature reaches 90oC and the other input parameters are in typical values, the overall COP of the R601 case reaches 0.49.