全玻璃真空管型太阳热水系统平均日效率的试验

Study on Average Daily-efficiency Experiments of Solar Water Heating System with All-glass Evacuated Tubes

全玻璃真空管型太阳热水系统的平均日效率是反映系统光—热转化能力的关键参数。选用6种不同型号规格的太阳能热水系统,在不同试验条件下分别用混水法和排水法测试系统的平均日效率。分析结果表明,采用排水法的测试结果得到是真正反映太阳能热水系统光热转化能力的平均日效率,而混水法测试结果只能得到系统水箱的效率。试验发现,同一样品的日有用得热量随着太阳累计辐照量增加而增大,而平均日效率则在适当的试验条件下达到最大。试验结果还表明,不同样品在相同条件下进行平均日效率试验,结果与其采光面积、容水量和集热器的吸热涂层有关。

Average daily-efficiency of solar water heating systems with all-glass evacuated tubes is regarded as a key parameter reflecting transform capability between solar light and heat. Six different kinds of solar water heaters are selected as the test samples and carried on different tests under different test conditions and different test methods. It is found that the average daily-efficiency results from drainage method can only reflect the transform capability between solar light and heat of the system, but the results from water-mixing method can not reflect the capability and can only gain their tanks＇ efficiency. At the same time, it is also found that the heat--obtaining quantity of the same sample is increasing with accumulative solar irradiation and its average daily-efficiency can reach the biggest under the appropriate test condition. The average daily efficiency results of different samples under the same test conditions is relating with contour aperture area,water volume of storage tank and coating layers of heat collectors.