This paper presents a mathematical model and discusses the influence of several convection heat transfer correlations and thermal efficiency schemes that have been commonly discussed in the literature regarding the performance of solar updraft system to choose the optimum forms conforming to the investigational result of the Spanish prototype. Hence, it is evident from the results of the study that the heat transfer coefficient correlation utilised by Kröger and Burger in 2004 was so close to the Manzanares experimental data. Also, the thermal efficiency equation used by Schlaich in 1996 is recommended to calculate the solar air heater collector's efficiency. ©2006-2016 Asian Research Publishing Network (ARPN).