Role of absorber and glazing in thermal performance improvements of liquid flat plate solar collector: a review

The requirement for heated water in residential buildings demands a substantial amount of energy. To accomplish the objective of conserving costly energy, an effective water heating technology is important. Solar water heater is a technically viable and economically efficient solar thermal technology in terms of installation and long-term operational cost. Many nations are presently utilizing this technology extensively for both domestic and commercial purposes. Because of its simple design, ease of installation, operation, and lower maintenance, flat plate solar collectors (FPSCs) are commonly employed in water heating applications than other solar collector. In order to increase the efficiency and thermal performance of FPSCs, several approaches and techniques have been adopted using design modifications of absorber and glazing. These modifications are associated with selectively coating on absorber plate, absorber material, absorber design modification, coating of glazing, number of glazing arrangement, glazing material, spacing between glazing etc. Furthermore, the research gap and recommended possible enhancements for future work have been provided, which is expected to help researchers in furthering the advancement of this technology.