Numerical investigation and optimization of the solar chimney performances for natural ventilation using RSM

In the present study, the finite volume method is applied for the thermal performance prediction of the natural ventilation system using vertical solar chimney whereas, design parameters are optimized through the response surface methodology (RSM). The computational simulations are performed for various parameters of the solar chimney such as absorber temperature (40<Tabs<70oC), inlet temperature (20<T0<30oC), inlet height of (0.1<h<0.2 m) and chimney width (0.1<d<0.2 m). Analysis of variance (ANOVA) was carried out to identify the design parameters that influence the average Nusselt number (Nu) and mass flow rate (m). Then, quadratic polynomial regression models were developed to predict of all the response parameters. Consequently, numerical and graphical optimizations were performed to achieve multi-objective optimization for the desired criteria. According to the desirability function approach, it can be seen that the optimum objective functions are Nu=25.67 and m=24.68 kg/h.m, corresponding to design parameters h=0.18 m, d=0.2 m, Tabs=46.81oC and T0=20oC. The optimal ventilation flow rate is enhanced by about 96.65% compared to the minimum ventilation rate, while solar energy consumption is reduced by 49.54% compared to the maximum ventilation rate.