Performance investigation of solar water heating system using flat-plate absorber integrated with thermal storage

Abstract

The solar water heating (SWH) technology is a cost-effective method of harnessing solar energy and widely used in various countries worldwide. Adding thermal storage to the flat-plate collector increases the performance of the SWH system. It contributes to reduce energy loss to the top and increases energy transfer to the water. A novel composite material as thermal storage integrated with a flat-plate collector is constructed to make it effective in absorbing and storing heat energy. This work aims to investigate the performance of SWH system by integrating Al + Al2O3 composite to the flat-plate collector at the bottom as thermal storage. The performances of two models of absorber plates including a standard flat-plate collector and with Al + Al2O3 composite as thermal storage are investigated experimentally. The Al + Al2O3 composites were also tested and characterized to obtain their thermal properties. The results show that adding Al + Al2O3 composite as the thermal storage to the absorber plate contributes to increase absorption of solar irradiation, heat storage, and thermal efficiency of the collector. Then, the collector model with Al + Al2O3 composite as the thermal storage provides higher thermal efficiency than that of the standard model. For example, the thermal efficiency of the collector model with composite thermal storage of alumina 35% and aluminum 65% at angle variation increase of 5.1 % (0°), 7.5 % (10°), and 2.5 % (30°). Thermal properties of Al + Al2O3 composites as the thermal storage are also presented. It concludes that the greater percentage of alumina content, the lower value of the thermal properties of the composite obtained.