Experimental study on performance enhancement of solar water heating system using latent heat energy storage

Abstract

Solar energy is a promising source of renewable energy, which can be utilized in converting incident solar radiation directly to heat energy, producing hot water for domestic and industrial applications. An electricity consumption of 1500 kWh y-1 can be saved through the replacement of electric heaters with solar water heating (SWH) systems, contributing to energy management during peak load in energy intensive sectors. Recently, compound parabolic concentrator (CPC) collectors are widely employed as they don t require complex tracking mechanisms. These collectors enable the effective collection of both direct beam and part of diffuse light, improving the overall efficiency and making them suitable for medium temperature applications. The mismatch between energy demand and supply due to the intermittency of solar energy can be overcome by using phase change materials (PCM). Proper selection of PCM is a predominantly influential criterion for achieving the targeted performance. A comprehensive literature review pertaining to CPC, TES systems and stratification studies was carried out, to identify the research gap. Considering the pressing need for the development of SWH systems, this work aims to develop a novel SWH system consisting of a CPC collector and the TES system (sensible and latent heat storage) and investigate the thermal performance under real-time operating conditions. newlineA dedicated test facility was built for carrying out the experimentation. The first step of the investigation involved the selection of PCM through stratification studies in sensible heat TES system at constant heat load condition. Water was taken as the heat transfer fluid (HTF) and the experiments were conducted at three different flow rates of 1 l minand#8722;1, 2 l minand#8722;1, 3 l minand#8722;1. A commercial PCM OM 65 was selected, based on the desired temperature driving potential at the top section of the TES system. A total of eighty spherical capsules each having an outer diameter of 72 mm, filled with 0.13 kg of PCM were placed at the top quart