Numerical Modeling of the Influence of Flat Solar Collector Design on Its Thermal Efficiency with the Use of Fractional Calculus

Abstract

The present study is dedicated to the issue of the operation of flat plate solar collectors with different tube cross-sections and different absorbers. Here, the flow of the working medium is analyzed in order to assess the influence of the type of tube cross-section and the type of absorber on the thermal parameters of the installation. Numerical tests were carried out on full-scale simulations with the use of Ansys Fluent software. The analysis showed that the efficiency of the system can be significantly improved by installing an appropriate absorber system. The results also show that changing the thickness and type of material the absorber is made of has a large impact on the efficiency of the collector. In this paper, to describe the phenomenon in question and to verify the obtained data, a mathematical model based on fractional order differential calculus is proposed. After comparing the flow of the working medium through collectors with different tube cross-sections with different types of absorbers, it was shown that the best results were obtained for a collector with a circular cross-section of tubes and an absorber made of copper with a thickness of 0.5 mm.