Thermal Analysis of Air-Heating Flat-Plate Thermal Solar Collectors

Abstract

All energy systems include heat transfer processes. Convection and radiation heat transfer play an important role in flat-plate solar thermal collectors. Where the solar collector can be considered as a heat exchanger, the absorber plate of the solar collector absorbs solar radiation and transfers this heat to the working fluid in the collector (water or air). The radiative and convective heat transfer processes inside the collectors depend on the temperatures of the components of the collector and on the hydrodynamic properties of the working fluid. Solar energy systems have proven their economic feasibility in most thermal applications, especially in the "sun belt" region. In order to fully exploit the potential of solar energy, it will be necessary to combine design with maximum performance and environmental considerations. This paper describes the thermal behavior of several types of air-heating flat-plate solar collectors, by knowing the field temperature distribution of solar collector's components. The simulation results showed that the solar collector of the double pass (fourth type) has the best thermal characteristics, but the solar collector of the single pass (second type) is almost similar to the double pass type in thermal characteristics and is distinguished from it by simplicity in design, more flexibility in work, and has less hydraulic losses, and therefore it is preferred in the global energy market.