Role of copper foam on solidification performance of ice-cool storage sphere system

Abstract

Due to the poor thermal conductivity of phase change material (PCM), the application of the ice-cool storage sphere system is hindered. In this paper, the solidification performance of heat transfer after adding copper foam to the ice-cool storage sphere system is numerically studied by Computational Fluid Dynamic (CFD). The enthalpy-porosity method is used to describe the PCM solidification. Local thermal equilibrium is numerically adopted for modeling the heat transfer between the PCM and the solid matrix in copper foam. The variations of temperature field, ice front evolutions, solidification fraction, total solidification time, and cold storage capacity are investigated with the consideration of natural convection. The influence of surface temperature is explored by Stefan (Ste) number. A new evaluation index is proposed that can evaluate the cold storage performance of the energy storage system in real-time. The results show the metal foam focuses on accelerating the upper heat transfer due to the influence of natural convection in the plain ice storage sphere. The total ice storage time can be reduced by at least 72.7% in copper foam ice storage sphere with the porosity of 0.97, at the cost of very little ice storage capacity reduction. A higher porosity of copper foam is recommended with a compromise on the total melting time. This paper provides a clear and comprehensive vision of the metal foam effects of different temperatures and porosity inside the ice-cool storage sphere systems.