复合抛物面太阳能集热器热性能分析

对真空管式复合抛物面太阳能集热器的传热模型进行了分析,在总热损失系数、效率因子、热迁移因子和瞬时效率表达式的基础上,建立了有盖板带翅片的复合抛物面集热器性能预测模型,并对有盖板和无盖板两种类型接收器的集热器进行了瞬时效率的对比计算.结果表明：当集热介质与外界环境间温差较小时,在相同辐射强度的情况下,有盖板带翅片的复合抛物面集热器的集热效率反而比无盖板的复合抛物面集热器的集热效率低;而当集热介质与外界环境温差增加到一定程度时,有盖板带翅片的复合抛物面集热器显示了其集热效率高的优点.

An Analvsis on Thermal Performance of CPC Solar Collectors

By analyzing the heat-transfer model of compound parabolic concentrator（CPC） evacuated tube collector, and based on expressions respectively for the overall heat loss coefficient, thermal efficiency factor, heat removal factor and instantaneous efficiency, a performance prediction model has been developed for the finned CPC collector with glass cover, while a calculation and a comparison made to the instantaneous efficiency of collectors with and without glass cover. Results show that the collector with glass cover has a thermal efficiency even lower than that without glass cover, under the same radiation intensity, when the temperature difference is small between the working medium and the environment; however, when the temperature difference gets up to a certain degree, the former one will be better than the latter one, i. e. the collector with glass cover will have a higher thermal efficiency.