中温地热能驱动的跨临界有机朗肯-蒸气压缩制冷系统的性能分析  

Performance Analysis of Transcritical Organic Rankine-Vapor Compression Refrigiration System Powered by Medium-Grade Geothermal Energy

作　　者：曹园树 胡冰[1,2] 梁立鹏[1,2] 卜宪标[1] 马伟斌[1] 

机构地区：[1]中国科学院广州能源研究所,中国科学院可再生能源重点实验室,广州510640 [2]中国科学院大学,北京100049

出　　处：《新能源进展》2014年第3期204-210,共7页Advances in New and Renewable Energy

基　　金：国家高新技术研究发展计划(863)项目(2012AA053003);国家自然科学基金项目(51106161);广东省中国科学院全面战略合作项目(2012B091100263);广州市珠江科技新星专项(2014J2200079)

摘　　要：跨临界有机朗肯-蒸气压缩制冷系统可以使工质与地热流体更好地匹配,减小系统的不可逆性。本文建立该系统的热力学模型,利用EES软件编程,分别对以R143a、R218及R125为工质的系统进行性能分析。计算结果表明,相比R218及R125,以R143a为工质的系统的性能是最佳的。为了避免膨胀机内产生湿蒸气,对于一定的膨胀机进口温度,膨胀机入口存在一个极限压力,并且存在一个最优压力使得系统的性能最佳。地热流体温度的升高可以提高系统的制冷能力,但系统的性能系数则随之先增大后减小;随着地热流体干度的增加,地热流体释放的潜热会大大增加系统的制冷量,而系统的性能系数保持不变。冷凝温度及蒸发温度对系统性能有着重要影响,其中冷凝温度的影响更为明显。以R143a为工质的跨临界有机朗肯-蒸气压缩制冷系统的最佳性能优于以R245fa为工质的亚临界有机朗肯-蒸气压缩制冷系统的最佳性能。The transcritical Organic Rankine-Vapor Compression refrigeration system can make working fluid well match geothermal fluid, benefit for reducing the irreversibility of the system. A thermodynamical model is set up to analyze the performance of the system selecting R143a, R218 and R125 as working fluid respectively. The calculation is conducted by the EES program. The results show that R143a is the most appropriate working fluid for the system compared with R218 and R125. To avoid wet vapor in the expander, the expander inlet has a limited pressure in a constant temperature. Moreover, there exists an optimum pressure for the system performance. A higher geothermal fluid temperature can improve the refrigerating capacity. However, the system performance coefficient may firstly increases and then decreases with geothermal fluid temperature increasing. As the geothermal fluid dryness increases, the higher system refrigerating capacity can be obtained, which results from the release of large amounts of latent heat, while, the system performance coefficient remains unchanged. The condensation and evaporation temperature have great effects on the system performance. Compared with evaporation temperature, condensation temperature has a more significant effect. The optimum performance of transcritical Organic Rankine-Vapor Compression refrigeration system using R143a as working fluid is better than that of subcritical Organic Rankine-Vapor Compression refrigeration system using R245fa as working fluid.

关 键 词：中温地热能 跨临界 有机朗肯-蒸汽压缩 性能分析 

分 类 号：TK529[动力工程及工程热物理—热能工程] TB66[一般工业技术—制冷工程]