真空管太阳能空气集热系统阻力影响因素研究

Influencing factors of resistance for evacuated tube solar air collecting systems

通过对真空管太阳能空气集热系统内部流动过程的分析,建立了集热系统阻力计算模型,分析了不同设计参数下真空管太阳能空气集热器、串联集热系统阻力变化规律。结果表明:随着集热工质温度升高,集热器阻抗呈指数减小趋势;各影响因素中,串联集热器数量和工质流量对系统阻力影响最大,集热系统各组集热器阻力随串联集热器数量增加呈增长率减小的增大趋势,随质量流量增大呈指数增大趋势,最大值为最小值的3.6倍。此外,系统阻力随环境温度、太阳辐照度、进口温度升高呈线性增大趋势,其中环境温度对系统阻力的影响可忽略不计。通过该研究建立的真空管太阳能空气集热系统阻力计算模型及总结得到的单位面积集热器阻力计算表,可为该集热器、集热系统阻力理论计算提供便捷可靠的依据。

Through the analysis of internal flow process of the evacuated tube solar air collecting system,establishes a resistance calculation model for the heat collecting system,and analyses the resistance changes of evacuated tube solar air collectors and series heat collecting system under different design parameters.The results show that with the increase of heat collector temperature,the impedance decreases exponentially.Among the various influencing factors,the number of series collectors and the working fluid flow have the greatest impact on system resistance.The resistance of each group of collectors shows an increasing trend of decreasing growth rate with the increase of the number of series collectors.With the increase of mass flow,the system resistance increases exponentially,and the maximum resistance is 3.6 times the minimum value.With the increase of ambient temperature,solar radiation intensity and inlet temperature,the system resistance shows a positive proportional increase trend,and the influence of the ambient temperature on the system resistance is negligible.The resistance calculation model of the evacuated tube solar air collector system established by this research and the calculation table of the resistance per unit area of the collector can provide a convenient and reliable basis for the theoretical calculation of the resistance of the collector and collecting system.