影响太阳能平板集热器抗冻性能因素分析

NUMERICAL STUDY OF ANTIFREEZE PERFORMANCE OF FLAT-PLATE SOLAR COLLECTOR

建立一个平板集热器的全天运行模型（包括白天集热模型和夜间降温冻结模型），采用青海西宁1月份平均气象数据，并通过数值离散和程序编写对模型进行求解。该模型可以得到集热器内部温度变化和排管内工质的同液相界面变化，进而可以确定影响集热器夜间抗冻性能的各种因素。研究结果表明：在常用平板集热器的基础上，缩小支管间距和改用较大直径的支管或集管以及增大卒气夹层厚度可以提高集热器夜间抗冻性能；使用TIM透明蜂窝或Low—E玻璃盖板均可显著提高集热器夜间抗冻性能。

An all day operation model for flat-plate solar collector （including heating process in the daytime and freezing process in night） was presented. The average meteorological data of Qinghai Xining in January were used to solve the model through numerical discretization and program compilation. The temperature variation inside the collector and phase change boundary of the working fluid in pipe can be obtained from the model. On this basis, the factors influencing the antifreeze performance of the collector in night were investigated. The results showed that the antifreeze performance of the collector can be improved by narrowing the pipe space, increasing the diameter of pipe and the thickness of the air gap, or utilizing TIM transparent honeycomb or Low-E glass cover.