Design improvement of a laboratory prototype for efficiency evaluation of solar thermal water heating system using phase change material (PCMs)

Abstract

Thermal energy in the solar thermal energy storage system cannot be stored for a long time during the evening hours as well as days that have minimal sunlight due to heat transfer to the surrounding atmosphere. PCMs are being implemented into these storage systems to enhance the thermal storage capacity of solar energy. PCMs based latent heat storage technique can extend thermal energy storage over long periods due to its ability to store energy. Several different types of PCMs with various chemical compounds and melting temperatures can suit various thermal storage applications in real life. However, the concept of combining these PCMs types with different ratios is an area within this field that has not yet been investigated as it is time-consuming and a matter of numerous combinations and trials. A model solar thermal energy storage system with the flexibility to test different PCM's blends can omit the problem. This research work intended to propose a design as testing apparatus that can successfully operate and investigate the different PCM's blends to find the optimum ratios for a highly efficient solar thermal water heating system. An appropriate laboratory-sized prototype design has described that can replicate the functions of a solar thermal water heating system. The necessary assumptions and mathematical relations are also presented for the proposed design.