为验证真空管集热器的真空保温性能及夜间防冻效果，通过实验对夜间静止工况下集热器内液体温度、集热器夜间散热量及平均热损失系数进行实测和计算，分析真空管集热器夜间热损失特性及其变化规律．结果表明：集热器内夜间最低温度一般位于8～25℃，夜间温降速率为0．7～1．3℃／h，夜间总散热量为1800～4700 kJ；测试期间平均热损失系数为0．427 W／（ m2·K）．集热器夜间热损失特性分析以及最低温度变化能够有效地表明集热器本身的保温性能，为严寒地区集热器和集热环路防冻提供依据和支持．%In order to verify the insulation features and anti⁃freezing protection effect of all⁃glass evacuated tube collector, the fluid temperature in solar collector and its changing were tested experimentally in static conditions in winter night, and the heat dissipation and the average heat loss coefficient were calculated as well. The heat loss characteristics and the changing regulations were analyzed in detail. Results indicated that the lowest fluid temperature was ranged from 8 ℃ to 25 ℃, and the temperature drop rate was between 0.7 ℃/h and 1.3 ℃/h. The total amount of heat dissipation was about 1 800-4 700 kJ, and the average heat loss coefficient was 0.427 W/( m2 ·K) during the testing nights. The study of the heat dissipation of solar collector and the changing of the lowest fluid temperature in it, can effectively demonstrate its insulation properties, which can provide evidence for the anti⁃freezing of solar collector and its outdoor pipe loops in severe cold areas.
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