Experimental studies on the impact of placing multiple PCMs in a domestic refrigerator: a techno-enviro-economics analysis

The refrigerator is one of the essential appliances of households, and it consumes a greater part of the domestic energy consumption. Therefore, manufacturers and researchers use numerous technologies to increase their energy efficiency as well as protect the environment. One primary strategy to tackle environmental issues is utilizing renewable energy sources (RES), such as solar energy. The application of phase change materials (PCMs) is a promising method for the effective utilization of power from RES. Though several studies used PCMs for refrigerators and established their potential to improve energy efficiency, the implementation of multiple PCMs with freezing temperatures near the freezer and chiller compartments needs a specific experimental study to determine the technological, economic, and environmental benefits of this strategy. This research developed a small-scale solar home refrigeration system that works with multiple commercially available PCMs and solar energy. An optimization study with HOMER Pro software provided the power supply by a 325 W solar module at the tested location. The study used four PCM materials and seven arrangements represented as AR1, AR2, AR3, AR5, AR6, and AR7. Since several studies established the energy efficiency of PCM, this study used pull-down time, compressor discharge pressure, variations in compressor discharge temperature at various ambient temperatures, financial viability, and total equivalent warming impact (TEWI) to ensure the applicability of this method. Among all the arrangements, AR5 and AR7 showed attractive performance parameters with the daily ON/OFF cycles 8.4 and 9.53, respectively. The addition of PCM increased the total cycle time and reduced the number of cycles per day, which is needed to overcome the intermittency of energy supply from RES. The identified arrangements, AR5 and AR7, reduced TEWI by 14.5% to 18.6%, and the energy savings from these arrangements can recover the additional expenses within 4.3 to 4.6 years. Thus, the implementation of this technique in home refrigerators could save electricity and lessen the refrigerator’s environmental effect.