一种低温太阳能热发电循环系统的理论分析

宋建忠^{1, 2}，张小松^{1, 2}

(1. 东南大学 能源与环境学院，江苏 南京，210096；
2. 常熟市东南应用技术研究院，江苏 常熟，215500)

摘 要：提出一种可以有效利用太阳能来生产电力同时也提供一定热能或热水的动力系统。该系统基于有机朗肯循环，采用低沸点工质作为循环工质。选用R245fa(五氟丙烷)为工质，针对该系统在理想循环与实际循环下的性能进行对比分析，分析膨胀机进口压力、膨胀机进口温度和过热度等对系统性能产生影响的一些关键因素，并对循环系统中是否带回热器对性能的影响进行对比分析。对设定输出功率为2 kW的系统进行分析。研究结果表明：膨胀机进口温度(压力)越高，系统的循环效率越高，而过热度需要综合考虑设置在合理范围内。

关键词：有机朗肯循环；低温太阳能；热发电；联供系统

A theoretical study on low-temperature solar thermal power cycle

SONG Jian-zhong^{1, 2}, ZHANG Xiao-song^{1, 2}

(1. School of Energy and Environment, Southeast University, Nanjing 210096, China;
2. Changshu Applied Technology Academy of Southeast University, Changshu 215500, China)

Abstract:A low-temperature power generation system based on Rankine cycle is proposed which can efficiently use the heat collected to provide electricity and co-provide certain amount of domestic hot water, and it employs the fluid with low boiling point as the working fluid. In this work, R245fa was selected as the working fluid. The cycle performance was analyzed based on the simulation of the ideal cycle and the working cycle. The effects of some key factors on the system were analyzed. These factors include the expander inlet temperature, the expander inlet pressure and the degree of superheat. Also, the performance of the system with and without a heat regenerator was analyzed. During this work, the power output was fixed at 2.0 kW. And the cycle efficiency increases with the increment of the expander inlet pressure (the expander inlet temperature) while the expander inlet temperature (the expander inlet pressure) is given. And the value of the degree of superheat should be synthetically considered.

Key words:Rankine cycle; low-temperature solar energy; power generation; co-generation system