新型太阳能混合蓄热罐的放热特性

Heat release characteristics of new solar hybrid heat storage tank

针对单罐系统的放热效率普遍较低,在单罐的基础上进行改进,增加一个壳管式相变换热器,构成单罐混合蓄热罐。建立了单罐混合蓄热罐的数值模型,将数值模拟结果与实验结果进行对比,研究了相同情况下混合蓄热罐与常规斜温层蓄热罐在放热特性方面的差异,并探究入口熔融盐速度和石英石颗粒直径的变化对蓄热罐放热特性产生的影响。结果表明,在入口熔融盐速度u_(in)=2.0×10^(–4)m/s下,混合蓄热罐的放热性能比常规斜温层蓄热罐更优;随着入口熔盐速度的增加,蓄热罐的总放热时间、有效放热时间以及放热效率均下降,并且混合蓄热罐中不同速度与放热效率有一定的比例关系;相对于常规斜温层蓄热罐,石英石颗粒直径的变化对混合蓄热罐放热性能的影响很小。

As the heat release efficiency of a single tank system is generally low,a hybrid heat storage tank is formed by adding a shell and tube type phase change heat exchanger to the tank.The numerical model of the hybrid heat storage tank was established,and the numerical simulation results were compared with the experimental results.The differences of heat release characteristics between the hybrid heat storage tank and the conventional thermocline heat storage tank were studied under the same condition,and the dependence of heat release characteristics of heat storage tank on different inlet molten salt velocities and quartz particle diameters was explored.The results showed that,when the inlet molten salt velocity uin was 2.0×10-4m/s,the heat release characteristics of the hybrid heat storage tank was better than that of the conventional thermocline heat storage tank.With the increase of inlet molten salt velocity,the total heat release time,effective heat release time and heat release efficiency of the heat storage tank were decreased,respectively.There was a certain proportional relation between the velocity and the heat release efficiency of the hybrid heat storage tank.Compared to the conventional thermocline heat storage tank,the change of quartz particle diameter had little influence on the heat release performance of the hybrid heat storage tank.