Energy and Exergy Analysis of a Multi-PCM Solar Storage System

Abstract

Latent heat storage using phase change materials (PCMs) is one of the most effective methods to store solar energy, and it can significantly reduce area for solar collectors. PCMs are isothermal in nature, and thus offer higher density energy storage and the ability to operate in a variable range of temperature conditions. In this paper, experimental study has been conducted to evaluate the effectiveness of the solar thermal storage system based on the energy and exergy analysis. Barium Hydroxide Octahydrate (BHO) and Sodium Acetate Trihydrate (SAT) were used as PCMs inside multi-capsule system arranged in series based on their melting temperatures. These two salts never being used together in a multi capsule solar storage system before. The capsules were charged by three water flow rates of 0.5 LPM, 1 LPM and 1.5 LPM that comes from a parabolic trough collector. The experimental results showed that the maximum energy and exergy storage of 139.38 kJ and 17.15 kJ, respectively were obtained from 1 LPM. In other hand, the maximum system energy and exergy efficiencies of 64.82 % and 14.99 %, respectively were obtained from the use of 1.5 LPM.