开放式热管中温太阳能空气集热装置的试验研究

Experimental research of medium temperature open heat pipe solar collector

设计一种使用简化CPC(非追踪式复合抛物线聚光板)集热板和新型开放式热管组合的全真空玻璃集热管中温太阳能空气集热装置。每个集热单元包括一个简化CPC集热板,一根全真空玻璃集热管,在玻璃集热管内安装一个铜管和外部的一个蒸汽包连接构成一个开放式热管结构。蒸汽包内安装螺旋换热管加热通过换热管的流动空气工质。分别使用水和CuO纳米流体作为热管工质,以空气作为集热工质,对热管式中温空气集热器的传热特性进行了实验研究。分析了不同工作压力、不同工质及纳米流体质量分数对热管集热传热特性的影响,详细比较了热管水工质和纳米流体工质在集热传热性能上的优劣。试验结果表明:本系统只使用2根玻璃集热管构成集热器,空气最大出口温度在夏天可达到200℃,在冬天可接近160℃,系统平均集热效率达到0.4以上,整个系统表现了良好的中温集热特性。

A collecting panel with simplified CPC(Compound Parabolic Concentrator) and a new all-glass evacuated tubular solar medium temperature air collector with open heat pipe combination were designed.Each collecting unit contains a simplified CPC collecting panel and an all-glass evacuated tube in which a copper tube was set.Connecting the copper tube and external steam box forms an open heat pipe.Spiral heat exchange tubes were set in steam box in order to heat air through the heat exchange.Water and CuO nanofluids were used as heat pipe working fluid and air was used as collector working fluid.An experimental study was carried on the heat transfer characteristics of the heat pipe collector.The Influences of different working pressures,different working fluids and nanofluids' concentration on transfer characteristics of collector was analyzed.Experimental study shows that the maximum air outlet temperature may amount to 200℃ in the summer and 160℃ in the winter and the average collector efficiency of the system is more than 0.4.The thermal resistance of heat pipe with nanofluids as working fluid is reduced by about 20% than the one with water as working fliud.