中文摘要：

针对中低温地热能发电,建立基于蒸发器夹点温差位置的有机朗肯循环（ORC）系统性能分析模型.以R245fa、R290和R600a工质为例,计算并分析了在不同蒸发器热源侧出口温度下,系统输出功率、单位面积的输出功率、蒸发压力、热效率和火用效率随蒸发器热源侧出口温度的变化规律,以及不同工质的最佳运行工况.研究结果表明：随着热源出口水温的升高,存在一个最佳蒸发器热源侧出口温度,使得循环的输出功率和有回热装置时的单位面积输出功率最大;对于≤135℃的地热能,更适用于亚临界ORC;回热器的加入可增加系统循环效率,但其对循环最优蒸发压力几乎无影响.

英文摘要：

The analytical model was established for organic Rankine cycle （ORC） system for power generation from geothermal energy.Three typical types of organic working fluids were selected for the ORC performance analysis.At different heat source outlet temperatures,change laws of the work output,work output per unit area,evaporation pressure,thermal efficiency and exergy efficiency with the heat source outlet temperature were investigated.Moreover,the optimal operation condition for each working fluid was obtained.The results show that,the work output （with and without internal heat exchanger （IHX）） and work output per unit area （with IHX） reached the maximum value with the variation of heat source outlet temperature.For geothermal with temperature below 135 ℃,subcritical ORC was more suitable for power generation than supercritical ORC.The introduction of IHX can increase the thermal efficiency and exergy efficiency,but has little effect on cycle optimum evaporation pressure.