Influence of Optical Properties of Glazing and Reflector Configurations on The Thermal Efficiency Of Integrated Solar Water Heating Systems

Abstract

Integrated solar water heating systems (ISWHS) rely on flat-plate or evacuated tube collectors to harness solar energy for domestic and industrial hot water needs. Glazing materials, with their transmittance, absorptance, and reflectance properties, govern the amount of solar radiation reaching the absorber plate, while reflector configurations like compound parabolic concentrators (CPCs) or V-troughs enhance incident radiation. This article explores how variations in glass thickness, anti-reflective coatings, and reflector geometries such as mirror spacing, angles, and types affect overall thermal performance. Drawing from experimental and simulation studies, it examines heat transfer mechanisms, optical efficiency gains, and practical optimizations. Key findings indicate that 4 mm low-iron glass yields peak efficiencies around 35%, while reflectors at 5 cm spacing and 30-degree angles can elevate temperatures to 318 K and efficiencies to 85%. Challenges like overheating and angle-dependent losses are addressed, alongside future directions involving nanofluids and advanced simulations. The analysis underscores the potential for 20-50% efficiency improvements, promoting ISWHS adoption in diverse climates.