Experimental Investigation on a Novel Composite Salt Gradient Solar Pond With an East–West Side Reflector

Abstract

Abstract A salt gradient solar pond (SGSP) acts as an eco-friendly and cost-efficient device for storing thermal energy storage. It is crucial to enrich the efficiency of the SGSP to boost its thermal energy storage. It can be efficaciously achieved with the application of salt mixtures, reflectors, and by the usage of a glazed layer. This current study investigates the hexagonal composite salinity gradient solar pond (HCSGSP) augmented with a dual inclined reflector and a triple-layer transparent cover. A micro-solar pond having a hexagonal cross section was fabricated and experimented at Coimbatore, India, having a datum and surface area of 1 m and 0.679 m2, respectively. The novel usage of composite salt (sodium chloride 30%, magnesium chloride 10%, and potassium chloride 60%) led to the enhancement of the daily average temperature of pond. The pond’s upper portion was packed with a triple-layer glazed cover which shows an uplift of thermal energy and the pond is provided with inclined reflectors made of plywood fixed with mirrors on the east–west direction. The purpose of the mirrors is to increase the solar radiation intensity during the diurnal period and also it acts as an insulator which minimizes the heat losses during the nocturnal period. Energy balance numerical equations were formulated for all layers in the pond and temperature variation was determined mathematically and experimentally. The maximum thermal efficiencies of the top convective, middle non-convective, and bottom convective layers of reformed solar pond were measured to be 23.44%, 30.68%, and 35.63%, respectively, whereas they were 1.32%, 12.32%, and 23.44%, respectively, in the case of conventional pond. Furthermore, the research provides insight into the impact of shading owing to sidewalls, which has a significant impact on the incident solar radiation and storage of thermal energy in the novel solar pool.