Mathematical model comparison of air type-phase change energy storage device and application optimization analysis

Abstract

Air Type-Phase Change Energy Storage Device (AT-PCESD) has great potential in reducing building energy consumption, by storing the coldness at night and releasing it during day. This study established one-dimensional and two-dimensional mathematical models for AT-PCESD, considering pure heat conduction and heat conduction and convection, and compared the error between them and the experimental results. Each group of comparative simulations contained 4500 pieces of data. Different integration methods for unsteady items were included in the two-dimensional pure heat conduction mathematical model solution. Thereafter, the two-dimensional model was used to analyze the effect of some controllable variables and discover its application effect in typical cold cities in China. According to the mathematical model comparison results, the error for one and two-dimensional mathematical model with natural convection is smaller than the pure heat conduction model, being 6.87 %, 5.16 %, 2.1 %,1.32 % for cool storage condition and 2.66 %, 2.47 %, 1.7 %, 1.62 % for cool discharge condition respectively. Time-integration method does not affect calculation result clearly under current conditions. The selection condition of step size in forward difference form is put forward through the error influential method. Further, in the simulated application operations, the AT-PCESD has the best effect in Beijing with an electricity saving rate of 27.34 %.