A bi-dimensional numerical study for the porosity effects on perforated GTC efficiency under constant surface heat flux condition

Abstract

In this paper, the flat-plate solar collector with different porosities is considered. The use of perforated absorbers has many advantages, including the diffusion of the absorbed radiation over the entire depth of the absorber, which increases the area of heat transfer and reduces the local flux density on absorbent surfaces. A parametric study based on numerical simulation is carried out by varying the absorber plate perforation diameter and fixing its spacing. The inlet mass flow rate is changed in a large interval in order to determine the optimal operating points. The heat diffusion and energy balance equations are formulated to be suitable to analyze the influence of the absorber plates’ perforation on the GTC thermal performance. That is why, the necessary basic assumptions are developed to simulate the heat exchange mechanism as accurate as possible. Therefore, the heated air thermal conductivity is neglected against that of the absorber which allows that constant surface heat flux condition to be applied at its outer well as well as at glazing cover. The methodology of simulation is completed by aided flowchart to handle the radiation loss and pressure drops’ validation.