Numerical Investigation of Cold Thermal Energy Storage Using Phase Change Material in Freezer

Abstract

Freezer is one of the electrical components that can be found in any building. Like any electrical appliance domestic freezer consumes a significant amount of energy during its working time. During recent decades a lot of solutions have been found to reduce this energy consumption. One of the most usable and appropriate ones is implementation of phase change material (PCM) in a Cold Thermal Energy Storage (CTES) system which can be installed in a household freezers. In this paper numerical investigation of using CTES system in a domestic freezer in order to diminish energy consumption during pick hours (18-22:30), is studied. Regard to the temperature ranges of the freezer, NaCl-H2O is used as a PCM in the CTES system. In a distinct period of time, a large amount of cold thermal energy in latent heat form is stored at low temperature in the PCM, and it is released in the freezer’s cabin when the compressor is off. Accordingly, numerical modeling and simulation using Computational Fluid Dynamics (CFD) software on charging and discharging cycle of PCM are done to measure cold storage period and amount of saved energy. The results reveal that using CTES could keep the freezer in the standard thermal condition without using a compressor, for 4.5 hours. These results show that if the PCM used in CTES system for a year, it could reduce energy, fossil fuel consumption and CO2 emission up to 45.7 kWh, 13.7 liters and 32.0 kg, respectively.