Low-Cost Potassium Chloride Saltwater Phase Change Material System for a Household Refrigerator

Abstract

Thermal energy storage systems (TESS) are receiving attention because there are constant power cuts, major changes in electrical rate structures, increased maximum power demands, and incentive programmes sponsored by utilities. Household refrigerators were one of the main consumers of residential electricity, as they consume up to 26% and have an additional 17% greenhouse gas emissions. By incorporating TESS, this figure can be reduced. This study presents a low-cost potassium chloride saltwater phase change material (PCM) system to maintain a household refrigerator compartment below 5 ° C to preserve food and pharmaceutical products. After determining the 5-liter volume of PCM required, the experiments were carried out on a KIC KBF 525/1 ME refrigerator with an average daily power consumption of 0.567 kWh. With a heat transfer rate of 5 W and a total of 80 kJ of energy, the PCM took 2.5 days to fully solidify. It was then able to maintain the frigerated compartment at a temperature below 5 ° C for close to 25 hours, resulting in a 8W output power and a total of 90 kJ of energy being released. For power consumption analysis, 1.4175 kWh was used during the charging phase and 0.567 kWh was saved during the discharging phase. Heat transfer during the charging phase needs to be improved to better optimise the TESS.