Combining Thermal and Optical Modeling to Optimize the Performance of a Flat Plate Absorber at Various Locations in a Solar Air Collector

Abstract

Increasing the absorber plate surface in a solar air heater system (SAHs) can increase thermal efficiency, heat transfer coefficient, and Nusselt number. This paper includes the development of a 3-dimensional computational fluid dynamics (3-D CFD) model for predicting the location of the absorber plate from the bottom of the collector, followed by its validation using experimental data. Various geometrical types are investigated to determine optimal design features, such as Type I, Type II, Type III, Type IV, and Type V. A comprehensive analysis is performed to achieve this goal, including thermal efficiency, heat transfer coefficient, and Nusselt number analyses. Results indicate that Type V has better performance than other geometries. When the absorber plate location Type V with a distance (dis) of 0.012 m far from the bottom of the collector. As a result, increases in the average thermal efficiency, heat transfer coefficient, and Nusselt number of the system are 19 %, 53%, and 268.8%. Compared to Type I, when the absorber plate was lying on the collectors without a gap between the absorber and collector bottom.

Keywords

• solar air heater; 3-d cfd modeling; optical and thermal modeling; heat transfer coefficient; nusselt number; thermal efficiency