摘 要：针对盐梯度太阳池具有长期聚热及跨季节蓄热的特性，选取R245fa作为循环工质，以实验用小型盐梯度太阳池下对流层60~90 ℃储存热量作为供热热源，建立盐梯度太阳池低温有机朗肯循环(ORC)发电系统数学模型，研究了有机工质的蒸发温度对系统性能的影响。分析结果表明：蒸发温度的变化对太阳池下对流层回热温度、系统工质流量、不可逆损失和效率都有着重要影响，另外蒸发温度变化对功率有双重影响，存在一个最佳蒸发温度，使得系统功率达到最大。

Abstract:The salt gradient solar pond has the characteristics of long term heat accumulation and seasonal storage.In this work,a mathematical model of the low temperature ORC (Organic Rankine Cycle) power generation system for the salt gradient solar pond was built and the effect of evaporation temperature on the system performance was studied.R245fa was taken as working fluid and the LCZ (Lower Convective Zone) heat with the temperature range of 60~90 ℃ from an experimental salt gradient solar pond was used as heat source.The results showed that the change in the evaporation temperature has important influence on the LCZ temperature ,working fluid flow,irreversible loss and the system efficiency.In addition,the evaporation temperature has a doublefold effect on the power,and there is an optimum evaporation temperature that maximizes the system power. Key words: solar pond,ORC,power generation,working fluid,thermal performance

TK512+.4

国家自然科学基金（51406173）；河北省自然科学基金（E2017203221）