Experimental Investigation of Solar Energy Storage Using Paraffin Wax as Thermal Mass

Abstract

World energy demands are expected to increase significantly due to global strong and continuous economic growth. On the other hand, energy availability, cost and environmental impacts are vital factors in the selection of future energy. Renewable energy resources such as solar, wind, and geothermal energy are promising alternatives for conventional fossil fuels. Solar energy is increasingly used as one of the most important renewable energy sources. The main advantages of solar energy are its easy deployment for different purposes and its power consistency throughout the year. However, solar energy has some drawbacks such as its limited availability during daytime only. This drawback can be overcome using solar energy storage using different available methods like battery bank and thermal mass. As a thermal mass method, phase change material (PCM) is widely used as an effective method of storing solar thermal energy using latent heat. PCMs provide many advantages including high energy capacity and constant temperature process. In the present study, a shell and tube air heater has been designed for solar energy storage using paraffin wax as phase change material (PCM). Electricity generated using photovoltaic panels is stored as latent heat of fusion of PCM in a bank of tubes. For charging period of 8 hours, a maximum of 61 ^oC has been reached for the PCM and a maximum of energy efficency of 77% has been achieved.