The main purpose of this study was to investigate the relation between different indices (velocity magnitude, duct height, and fin types) and temperature by Evolutionary Polynomial Regression (EPR) for a PV/T system. At this study, the highest cell temperature was 51 °C at 0.5 m/s, while the best result was 33 °C that it was gained at 4 cm duct height, rectangular fin and 3 m/s velocity magnitude. Five different models have been presented. The Coefficient of Determination (CoD) of these models is 88.36, 97.33, 97.76, 98.15, and 98.42, respectively. The higher the CoD becomes, the more complexity of the model is. According to the models, the velocity magnitude has the exponent of “-0.5” and the duct height has the exponent of “0.5”.
