Numerical simulation study on heat transfer characteristics and parameter optimization of solar phase change energy storage fresh air preheating system

Abstract

In cold regions, indoor fresh air preheating in winter has received much attention. An improved fresh air preheating system using solar energy and phase change energy storage technology is proposed in this study to solve the problem of insufficient fresh air supply in cold regions. This study establishes two-dimensional mathematical model for air-type phase change energy storage device, and compares the error between them and the experimental results. The results show that the comparison between the simulated and experimentally measured is in good agreement. This study explores the effects of velocity of hot air, temperature of fresh air and temperature of hot air during simultaneous heat storage and discharge conditions by using numerical simulation method. The results show that the designed system has the ability to preheat fresh air at 4.5 °C for more than 4 hours under the condition of outdoor average temperature of -10 °C at night, and has practical promotion value. All three parameters affect the thermal performance of the system. When the hot air velocity increases from 1.5 m / s to 2.25 m / s, the liquid fraction increases by 5.16 %, 10.11 % and 14.52 % respectively. Different fresh air temperatures determine the heat storage capacity of the system under the condition of simultaneous heat storage and heat release.