全玻璃真空集热管的热损

HEAT LOSSES OF THE ALL-GLASS EVACUATED COLLECTOR TUBES

对一种具有溅射Ａｌ－Ｎ／Ａｌ吸收表面的全玻璃真空集热管的辐射热损进行了测量。在氦对所用硼硅玻璃渗透１３．５年实验的基础上，考虑了渗氦对集热管真空度的影响。分析和比较了辐射热损与气体导热热损的大小，在集热管真空度Ｐ≤６．７×１０－３Ｐａ时，辐射热损比气体导热热损约大２—３个数量级；集热管在整个使用期间直至２０年，通常辐射热损始终占热损的最主要部份。提出了为降低热损，在生产中应注意的若干问题。本文还报道了一种简单易行的非稳态卡计法测试与计算整管在１００℃以下的总热损与等效发射率的方法并给出了实例。

Radiation heat loss for a all-glass tubular evacuated collector with sputtered aluminium-nitrogen selective surface was measured. On the basis of the experiments on helium permeated through the borosilicate glass tube for 13.5 years. the effects of He permeation was taken into consideration. Radiation heat loss and conduction heat loss were compared and analysed. according to our operation practices about 20 years. the rediation heat loss is a major portion of the total heat loss. This paper reported a simple and conyenient unstable-state method to roughly estimat total heat loss of the collector tubes under the temperature of 100℃.