Study of Some Factors Affecting the Efficiency of the Flat Plate Solar Collector - (Theoretical Study)

Abstract

The performance and efficiency of a flat plate solar collector with thin absorber The performance and efficiency of a flat plate solar collector with thick absorber

For the first case, the thermal field is homogenous (i.e., there is no temperature gradient across the absorber plate). The heat balance equation is applied to determine the temperature of the absorber and the temperature of the working fluid. An expression for the efficiency is obtained.

For the second case, in which we considered a thick absorber, a temperature gradient across the thickness of the absorber does exist. The heat diffusion equation is solved using Fourier series expansion technique together with Fourier law and a heat balance equation in an integral form. The temperature of the absorber and the working fluid are obtained. Their variations along the local solar day time are obtained. Moreover, the expression for the efficiency is also obtained. Different operating conditions are taken into consideration such as: i) Different materials of the absorber plate (Copper, Aluminum, Mica and Silicon carbide) with different geometrical parameters. ii) Different cooling conditions by convection through different values of the heat transfer by convection ℎ are taken. iii) Different flow rates of the fluid are taken into consideration. The working fluid in both cases is water. The obtained results are tabulated and presented graphically. A comparative comments on the obtained data are given.