Phase Change Materials (PCMs) for the Use of Solar Energy in Cooling Applications

Abstract

The entire modern world is dependent on energy. Providing cooling with renewable energy sources, such as solar energy, is one of the primary answers to the energy and environmental issues. Phase change materials (PCMs) play a significant role in the utilisation of solar energy in cooling applications. Recent study on solar energy using PCMs for low and medium temperature cooling applications indicates that PCMs are widely employed in solar thermal cooling, transport refrigeration, and commercial food outlets. Since low-temperature PCMs can maintain the temperature of small-scale refrigerators for an extended time, it can be used to maintain the space temperature of the appliance without the use of an electrical energy storage during the night. The primary factors in adapting a conventional system to work with solar energy with PCM are performance parameters such as pull-down time and on-off cycle of the compressor. In this paper, therefore, the experimental findings for the pull-down time and on-off cycle time of a 210-liter solar refrigerator with and without a PCM are provided. The experimental data revealed that the compressor's pull-down time and off-time were raised by 78% and 6.1 times, respectively. In addition to enhancing performance and facilitating temperature maintenance within the refrigerated space, the per-day energy consumption was reduced from 14.4 to 18.5% as compared to the system without PCM. It was confirmed that the use of PCM in refrigeration systems can play an essential role in enhancing their overall performance. Furthermore, this study could serve as a key link between the PCM and all currently available small-scale solar-powered household cooling appliances.