重力热管平板集热器中的热管工质的选择——重力热管太阳能平板集热器之一

首先,根据太阳能平板集热器的要求,提出了重力热管工质的选择原则;第一是与钢管的相容性;第二是传热性能好;第三是容易沸腾。其次对水、氨、丙酮、甲醇、乙醇、庚烷、戊烷、氟利昂—11及氟利昂—12等工质进行了计算分析。在计算分析的基础上,我们选择了五种典型的工质——水、氨、丙酮、甲醇及氟利昂—12,进行了热管性能的实验研究,得到了热管的总传热系数、起动热流与急剧沸腾起始热流。计算分析与实验结果皆表明:理想的重力热管太阳能平板集热器中的热管工质,首先是氨、其次是氟利昂—12与丙酮。但从实用角度来看,氟利昂—12与丙酮是比较理想的工质。

SELECTION OF THE WORKING LIQUID FOR THE GRAVITY HEAT PIPES IN A SOLAR PLANE-PLATE COLLECTOR

The working liquid selected for gravity heat pipes in a solar plane-plate collector must first be suitable to steal tubes,secondly have a good heat- transferring property,and thirdly easy to boil.We have thus made a series of calculations and analyses for some media such as water,ammonia,acetone, carbinol,ethyl alcohol,heptane,pentane.F-11 and F-12,and from among them, water,ammonia,acetone,carbinol and F-12 were selected as the working liquid for the heat pipes in our experiment.Through the experimental study,the total heat transfer coefficients,the starting heat flows and the starting heat flows of sudden boiling in those heat pipes were obtained.Our results show that among others ammonia is the most ideal working liquid for the heat pipes in a solar plane-plate collector,but F-12 and acetane would be more available in view of the practical use.