Heat Flux Analysis of a Solar Thermal Collector Incorporated With Optimized Involuted Reflectors

Abstract

Solar energy plays a vital role in the future of clean energy production due to its availability all year round. Some prominent solar energy technologies, e.g. concentrating solar power (CSP), have the ability to focus/concentrate sunlight for large-scale commercial use. Meanwhile for smaller-scale residential use, solar water heating (SWH) systems are often used to provide hot water for household applications, where the solar collectors are the main components of such systems. The type of solar collector of interest in this study is the heat pipe evacuated tube collector (HPETC). To enhance the system’s thermal and optical efficiencies, this study investigates the incorporation of a custom-made involuted reflector mirror to a single HPETC through employing SolTrace’s optical ray tracing method, where the heat flux around the circumference of the absorber tube can be obtained. The maximum and averaged heat flux is compared between a traditional HPETC system and the HPETC system with the involuted reflectors. The result from this study showed that the HPETC system with an optimized involuted reflector experiences up to ∼ 55.3 % increase in maximum heat flux, and an increase up to ∼ 81.2 % in average heat flux across the absorber tube. Consequently, the HPETC incorporating the custom-made involuted reflectors yields to more collected heat and is capable of providing more hot water to be used for residential SWH applications.