槽式太阳能集热系统集热性能试验研究

Experiment on Collector Performance of Parabolic Trough Solar Collecting System

槽式太阳能集热系统在太阳能热发电领域的应用比较成熟,由于其光-热转化效率高的特点,近些年在牧草干燥领域的应用也越来越多。为了进一步提高牧草干燥效率,以槽式太阳能集热系统作为稳定的干燥热风能源输出,研究其真空集热管集热性能和热损失是槽式太阳能热利用的关键。利用槽式太阳能集热系统加热导热油储能,通过追踪真空集热管进、出口温度和真空集热管内温度,阐述了进入真空集热管内的导热油瞬时温度与集热器瞬时光热转换效率和真空管热损失的关系。结果表明,集热器瞬时光热转换效率与导热油进入真空集热管的温度有关,进入真空集热管导热油温度越低,换热越充分,真空集热管热损失越少,真空集热管瞬时光热转换效率越高。加大真空集热管出口和入口的导热油温差是提高槽式太阳能集热蓄热能力的关键。

Because of its high photo-thermal conversion efficiency,the parabolic trough solar collecting system in solar thermal power generation is more mature. Therefore,in recent years more and more applications were made in the field of forage drying. In order to further improve the efficiency of forage drying,as steady output of dry hot wind energy,the parabolic trough solar collecting system,the heat collecting performance and heat loss of vacuum heat collecting pipes were studied. Through studying,the factors that improved the heat gathering efficiency of the system was found out. Tracking the inlet,outlet and inner temperatures of a vacuum heat collector by heating the heat transfer oil storage energy using a slot solar heat collector system. The effect of instantaneous temperature of heat transfer oil was discussed from different angles,especially when entering vacuum heat collector on the transient heat conversion efficiency of heat collector. It can be deduced from the opposite side that the instantaneous heat conversion efficiency of the collector was related to the temperature of the heat guide medium when entering the collector. The lower the temperature of the heat transfer oil of the collector was,the more full the heat exchange was,and the less the heat loss of the vacuum heat collector can be got,the higher the instantaneous heat conversion efficiency of the collector can be obtained. So how to increase the heat transfer oil temperature difference between the outlet and inlet of the collector was the key to improve the heat storage capacity.