A Comparison Study of Sensible and Latent Thermal Energy Storage Used in Domestic Hot Water Solar Heating System

Abstract

Numerical analysis of domestic hot water solar system with sensible and latent thermal energy storages (TES), for specific residential building, has been presented in this paper. Numerical models of systems are developed in the Trnsys environment, consisting of the sensible or latent thermal energy storage tank, the flat-plate solar collectors, pump, differential controller and auxiliary heating source. Realistic meteorological conditions and standard user load profile were used as input parameters. The latent thermal energy storage tank contains sodium acetate trihydrate with added graphite powder, as phase change material (PCM), filled in cylindrical capsules and integrated into the tank, filling approximately 11% of total tank volume. The set of transient numerical simulations has been performed for a different tank volume and collector area ratios, ranging from 0.03 to 0.16 m(3)/m(2) . The performance of latent thermal energy storage system is compared with conventional sensible thermal energy storage system in terms of: collector efficiency, system efficiency, solar fraction and auxiliary energy consumption. The results of simulations indicate that latent thermal energy storage has advantages for specific tank volume to collector ratios, when the average temperature inside the tank is approaching the melting temperature of PCM.