液态金属与传统介质下槽式集热管性能对比

THERMAL PERFORMANCE COMPARISON OF PARABOLIC TROUGH SOLAR COLLECTOR OPERATED WITH LIQUID METALS AND CONVENTIONAL FLUIDS

对比液态铅铋、液态钠、熔盐及导热油的热物性,从换热和储能性能等方面探讨液态金属作为传热介质在槽式集热管中应用的可行性。基于能量守恒原理建立槽式集热管二维稳态传热模型,通过与文献实验结果对比,验证数值计算模型的准确性。在此基础上,分析不同传热介质下槽式集热管的集热性能及其影响规律。结果表明:液态金属作为传热介质具有较好的换热性能有助于提高集热效率,熔盐作为储能介质更具经济性;不同传热介质下的集热效率变化规律相似,其中阳光辐射指数DNI、出口温度及压强对集热效率影响较大,环境风速的影响相对较小。

In order to improve the efficiency of PTC,two liquid metals,namely Lead-bismuth eutectic(LBE)and Sodium(Na),were proposed as efficient heat transfer fluid(HTF)in this paper.The thermal properties of LBE,Na,molten salts and Syltherm 800 oil were compared,and the possibilities of application of liquid metals in PTC were discussed.In addition,the influence of Direct Normal Irradiation(DNI),outlet temperature,annular space pressure and wind speed with different HTF was analyzed based on a 2D theoretical heat transfer model.The results indicate that liquid metals,as HTF,can improve the efficiency of solar power plant,and the solar salt is appropriate for the energy storage materials.Besides,the change tendency of thermal performance of PTC operated with four types of HTF is similar.The solar collect efficiency of PTC is strongly affected by the DNI,outlet temperature and annular space pressure,while that of wind speed is relatively small.Due to the excellent heat transfer properties,the thermal performance of PTC can be improved dramatically when the liquid metals were selected as HTF.