低温热源喷射式发电制冷复合系统特性分析

低温热源喷射式发电制冷复合系统特性分析

郑彬，翁一武，顾伟，翁史烈

(上海交通大学机械与动力工程学院，上海市闵行区200240)

Analysis of a Combined Powerand Ejector Refrigeration Cycle for

Low Temperature Heat Sources

ZHENG Bin，WENG Yi—wu，GU Wei，WENG Shi—lie

(School of Mechanical and Power Engineering，Shanghai Jiao Tong University，Minhang District，Shanghai 200240，China)

ABSTRACT：A combined power and refrigeration cycle isproposed.The proposed cycle combines the organic Rankinecycle and the ejector refrigeration cycle，producing power as,ell as refrigeration simultaneously.The ejector is driven by the exhausts from the turbine.After the efficiency definition of the combined cycle，a simulation model was established for calculation and analysis.R245fa Was chosen as the working fluid for its good performance.At the typical working conditions generating temperature T92120。C，evaporating temperature Te=7"(2 and condensing temperature Tc=25’C，the first law efficiency of the combined cycle Can be 37%，the practical first law efficiency Can be 15.6%and the exergy efficiency Call be 37.5%.Results show that performance of the cycle call benefit from increasing generating temperature，increasing evaporating temperature and decreasing condensing temperature瓦.It is found that larger power refrigeration ratio R Can be obtained by increasing expansion ratio 8.

KEY WoRDS：combined power and refrigeration cycle;organic Rankine cycle;ejector refrigeration cycle;waste heat recovery;low temperature heat sources

摘要：提出一种低温热源喷射式发电制冷复合系统。该系统将有机物朗肯循环与喷射式制冷循环相结合，利用透平排气驱动喷射器工作，同时实现发电和制冷的功能。在定义系统评价指标的基础上，选取性能优良的有机物R245fa作为工质，建立系统仿真模型，进行计算分析。计算结果表明，在热源蒸发温度7≯120"C。制冷蒸发温度7≯7℃，冷凝温度Te=25"C的标准工况下，系统的热力学第一定律效率可达37%，热力学第一定律折合效率可达15.6%，烟效率可达37.5%。分析同时表明，提高热源蒸发温度疋，提高制冷蒸发温度瓦，降低冷凝温度疋，有利于提高系统的工作性能;提高透平膨胀比网以提高系统电冷比R。

关键词：发电制冷复合系统;有机物朗肯循环;喷射式制冷循环;余热利用;低温热源

0引言

目前，在能源利用过程中产生的低温余热往往被直接排放到环境中去，这样既浪费了大量的能源，又对环境造成了污染。伴随着世界范围内能源供给的口趋紧张，寻找合理利用低温热源的方法已经成为当前能源技术领域中的一个重要课题。近年来，国内外诸多学者相继提出了一些热源温度在100，350℃之间的动力，制冷复合循环能源利用的新途径。