含球形相变胶囊的混合储能水箱特性模拟研究

储能水箱是在太阳能光利用过程中的重要元件，是协调未来能源供需平衡，解决可再生能源空间不足的有效方法之一。本文是对含有相变胶囊的混合储能水箱特性进行模拟研究。采用RT35作为相变材料，水作为传热流体，创建了储能水箱的含相变胶囊的数值模型，模拟水箱内部的蓄热过程，探究水箱内热分层机理。水箱内部温度为278.15K，入口温度为353.15K，采用了理查德森数、平均蓄热率和平均蓄热密度作为储能水箱的储能评价指标，对不同的相变胶囊高度、不同的入口流速以及不同的相变胶囊尺寸进行了模拟实验。实验结果表明，随着相变胶囊距水箱底部的高度越高、相变胶囊直径越小，理查德森数越大，平均蓄热率和蓄热密度越大。入口流速越小，理查德森数越大，平均蓄热率和蓄热密度越小。相变蓄热胶囊内相变材料一半进行液化所需的时间与入口流速、相变胶囊尺寸成反比，与相变相变胶囊的距水箱底部的高度成正比。

Simulation study on characteristics of hybrid energy storage tank with spherical phase change capsule

The energy storage tank is an important element in the process of solar energy utilization, and is one of the effective methods to coordinate the future energy supply and demand balance and solve the shortage of renewable energy space. In this paper, the characteristics of hybrid energy storage tank with phase change capsule are simulated. Using rt35 as phase change material and water as heat transfer fluid, a numerical model of the energy storage tank containing phase change capsule was established to simulate the heat storage process in the tank and explore the thermal stratification mechanism in the tank. The internal temperature of the water tank is 278.15k and the inlet temperature is 353.15k. The Richardson number, the average heat storage rate and the average heat storage density are used as the energy storage evaluation indexes of the energy storage water tank. The simulation experiments are carried out for different ball heights, different inlet flow rates and different ball sizes. The experimental results show that the higher the height of the phase change capsule from the bottom of the water tank and the smaller the diameter of the small ball, the larger the Richardson number, the larger the average heat storage rate and the heat storage density. The smaller the inlet flow rate, the larger the Richardson number, and the smaller the average heat storage rate and heat storage density. The time required for half of the phase change material in the phase change heat storage capsule to liquefy is inversely proportional to the inlet flow rate and the size of the small ball, and is directly proportional to the height of the phase change small ball from the bottom of the water tank.