Practical approaches to assess thermal performance of a finned heat sink prototype for low concentration photovoltaics (LCPV) systems: Analytical correlations vs CFD modelling

Abstract

The performance of a low-cost extruded heat sink prototype for a Low Concentration Photovoltaics system is studied using various analytical correlations and CFD simulations. An experimental test, with temperature measurements at different monitoring points of heat sink surface, was carried out in order to select the most appropriate approach. Large deviations (of up to 20 °C) in the estimation of base plate temperature from correlations were found when compared to experimental results, probably due to the specific geometry characteristics of the heat sink, with variable fin thickness and high fin length. Furthermore, discrepancies of up to 48% have been found among the different correlations. The numerical CFD results of temperature at monitoring points and at the base plate showed relative errors of about 1%, which were at least 15 times smaller than the results given by analytical correlations. Also, numerical simulations allowed the identification of stagnation zones due to the great length of the heat sink and characteristic air flow patterns, which help to explain its performance under different operating conditions. Thus, results showed that multiple chimney flow pattern and air stagnation zones seem to disappear for inclination angles greater than 30°.