Recent development in thermal performance of solar water heating (SWH) systems

Abstract

Solar energy is best suited substitute energy source owing to its cost-effectiveness and eco-friendly nature. But, the irregular nature of solar energy limits its usage and efficacy in domestic and industrial applications, particularly for water heating. Various research reports demonstrated that increasing convective heat transfer rate and energy storage capacity could increase the thermal output of solar water heating (SWH) systems. Active and passive types are two categories of SWH systems. The aim of the present study is to discuss a crisp review of recent developments made in the field of SWH systems, and focusing on ways used to enhance their thermal performance. The thermal performance improving methods that have received specific attention include geometrical changes to the absorber plate, solar selective coatings, collector tilt angle, fluid flow rates, phase change materials as a thermal energy storage unit, and twisted tape insertion. This study also helps to understand the physical science and mechanism behind the performance enhancement methods used in SWH systems for sustainable energy development.