Finite Element Analysis and Numerical Simulation of Performance Deterioration in Flat-Plate and Parabolic Solar Collectors

Abstract

This study introduces a finite element method (FEM) mathematical model integrated with numerical simulations to assess and forecast degradation of thermal and optical performance in two solar collector types: flat-plate collectors (FPC) and parabolic trough collectors (PTC). Degradation is modelled using exponential decay laws for optical properties (absorptance, transmittance, and reflectivity), an increase in the fouling resistance of the tubes, accompanied by a gradual deterioration of the overall heat loss coefficient ????_????. The heat transfer equations (conduction, convection, and radiation) are discretised using finite elements on one-dimensional and two-dimensional structured meshes. They are then solved numerically using the programmes we have developed in MATLAB® and Python. The 1D, 2D, and 3D figures illustrate the temperature fields, efficiency surfaces, the progression of optical characteristics, and the cumulative energy losses over 25 years of operation. The results indicate that the FPC suffers a performance degradation of around 22–28% after 25 years, whilst the PTC sees its optical efficiency drop by 14–18%. These results are compared with experimental data from the international literature, demonstrating excellent agreement with the work of Duffie & Beckman (2013) [7], Kalogirou (2014) [8] and Saleh Im (2020) [9].