Recent Developments in the Thermal Performance of Flat Plate Solar Water Heaters with Reflectors-A Review

One of the most extensively used forms of energy is solar energy. It is a widely utilized, low-cost, eco-friendly, sustainable, emission-free renewable energy source, and it reduces power costs from coal, electricity, and other sources. Solar energy is utilized for several reasons, such as water heating in homes and industrial applications using solar collectors. Unlike other solar collector energy applications, flat plate solar collector techniques for water heating offer low maintenance and operational expenses. This article reviewed the innovations of flat plate solar collectors for improved thermal performance with reflectors in solar water heaters. The impact of combining flat plate solar collectors and reflectors for thermal performance improvements is discussed in this article. Integrating flat plate solar collectors using reflectors is an effective and cost-effective approach among the numerous geometries utilized for thermal performance improvements. In order to improve SWH performance, researchers have implemented a number of modifications so far. These modifications are associated with various types of reflector integration in SWH such as booster mirror reflector, plane reflector, side reflector, bottom reflector, top-edge reflector, inclination angle of reflector, gap between reflector and collector, trapezoidal reflector, parabolic reflector, polyline reflector etc. The major goal of this paper is to evaluate several studies wherein different reflectors have already been utilized to improve thermal performance and to recommend a design for the best performance. Furthermore, the research gap has been identified, along with suggested upgrades for future study, which should benefit researchers in extending the growth of this technology.