太阳能相变储能水箱释能性能的数值模拟

摘要

Numerical simulations were carried out on the discharging behaviour of a thermal energy storage water tank containing PCM modules and a tank containing only water. The modeling was done by using a CFD software package FLUENT. The results show that the cold inlet water can be heated by the PCM module during the discharging process and the PCM modules also act as a diffuser to reduce the disturbance caused by the inlet cold water. The PCM modules improve the thermal stratification of water during the discharging process. At a flow rate of 5 L/min, the discharging efficiency of the tank with PCM modules is 7% higher than that of the normal tank and the discharging efficiency of the water tank with PCM modules decreases with increasing water flow rate.%　　采用数值模拟软件 FLUENT 对含有相变储能模块的储热水箱（下文简称为相变储能水箱）和不含相变储能模块的普通水箱（直接进水）的释能工况进行数值模拟，并将模拟结果进行了对比。数值模拟结果表明水箱加入相变储能模块后，一方面相变储能模块的堆积起到了散流作用，减缓了进口水流造成的扰动；另一方面冷水进入水箱中通过相变储能模块缝隙时，相变储能模块对冷水有一定的加热作用。加入相变储能模块后，改善了释能过程的水箱内热分层效果，提高了储热水箱的释热总量。在流量为5 L/min 时，相变储能水箱的释能效率比普通水箱的释能效率高7%，但是随着流量的增大，相变储能水箱的释能效率逐渐降低。