直通式太阳能真空管集热器热性能分析

通过对直通式太阳能真空管传热模型的分析,在导出单根带翅片与不带翅片的直通式太阳能真空管的总热损失系数、效率因子、热迁移因子和瞬时效率的基础上,建立了直通式太阳能真空管的性能预测模型;针对由多根并联、顺流布置的直通式太阳能真空管组成的平行流集热器,对比计算了带翅片与不带翅片两种真空管及由其组成的集热器的瞬时效率。结果表明,在工质流量,进口温度,环境温度等条件相同的情况下带翅片的直通式太阳能真空管以及由其构成的集热器的瞬时效率分别比不带翅片的太阳能真空管及集热器提高很多;并联直通式太阳能真空管间的流量分配不均匀性致使集热器的整体效率低于单根真空管的瞬时效率。

Thermal Performance Analyses of the Direct Pass Vacuum Tube Solar Collector

The heat transfer model of direct pass solar vacuum tube is analyzed.Based on the overall heat loss coefficient,the prediction models to calculate the performances such as thermal efficiency factor,the heat removal factor and the instantaneous efficiency of tubes with fins and without fins,are developed.As for the solar collector composed of multiple parallel downstream arrangement of direct pass vacuum tube,the instantaneous efficiency of tubes with fins and without fins are compared with each other.The results show that the instantaneous efficiency of direct pass vacuum tube solar collector with fins is much higher than that without fins on condition that the refrigerant flow rate,inlet temperature,ambient temperature are kept the same.The uneven distribution of flow rate between rows of collector results in a decline in the overall efficiency compared with the single vacuum tube.