无盖板渗透型集热器热性能的对比试验

利用太阳能空气加热系统实验台,对黑、深绿和深蓝3种颜色无盖板渗透型集热器的热性能进行了户外瞬态对比试验。试验结果表明:太阳辐射照度和风量是影响系统热性能的重要因素。在高档和低档两种风量下,黑色集热器的瞬时平均热效率分别为76.04%和67.50%,高于普通平板太阳能空气集热器;集热器表面颜色对其热性能有一定影响,在高档和低档两种风量下,深绿色和深蓝色集热器的瞬时平均热效率比黑色集热器低15%～22%,空气温升低3～4℃,但仍然优于普通平板空气集热器。从保持建筑立面美观考虑,无盖板渗透型集热器的集热板可以采用颜色较深的彩色,不会对系统热性能造成较大影响。

Experimental comparison of the thermal performance of unglazed transpired collectors

The thermal performances of black,dark green and dark blue unglazed transpired solar collectors were tested and compared under real transient outdoor conditions using an experimental solar air heating system.The test results show that solar irradiation and air flow rate are the main influencing factors for the thermal performance of solar air heating system.The average instantaneous thermal efficiency of the black collector under high and low air flow rate is 76.04% and 67.50%,respectively,which are higher than that of conventional glazed flat-plate solar air collectors.Surface color of solar air collectors has effect on its thermal performance.The average instantaneous thermal efficiency of the dark green and dark blue collector under high and low air flow rate is 15% to 22% lower than that of the black collector,temperature rise is 3～4 ℃ lower than that of the black collector.However,the thermal performances of dark green and dark blue collector are better than that of conventional flat-plate collectors.Thus,the thermal performance penalty will not be very high with the application of colored unglazed transpired collectors on building facade for aesthetic reasons.