Numerical investigation of two-dimensional heat transfer of an absorbing plate of a flat-plate solar collector using dual-reciprocity method based on boundary element

Abstract

In this paper, heat transfer in an absorbing plate of a flat plate solar collector has been investigated upon using dual-reciprocity method. In order to validate the boundary element method, the results of this method have been compared with the numerical results obtained by finite difference method. Due to the presence of non-homogeneous terms in the governing equation, it has been numerically solved using the dual-reciprocity boundary element method. The temperature distribution in the absorbing plate is investigated upon considering different values of mass flow rate in the tube and the results obtained by the dual-reciprocity boundary element and finite difference methods are compared. Additionally, the fluid temperature along the tube has been studied, using two numerical methods. After being compared, the results of two methods well coincide, which proves the accuracy of numerical methods. Moreover, effect of changes in various parameters such as conductivity of the absorbing plate, mass flow rate, distance between two tubes, the fluid inlet temperature, as well as the change in the diameter of the tubes on the efficiency of the absorbing plate has been thoroughly investigated. Another notable point is that the boundary element method can lead to less computational cost, compared to other numerical methods such as finite difference method. The reason for this is connected to the capability of the boundary element method, without need for points within the computational domain.