Parametric investigation on the performance of natural convection flat plate solar air collector with additional transparent insulation material parallel slats (TIM-PS)

•Performance of SAH operating in natural convection with TIM-PS was investigated.•Vertical position is the most efficient when operating with natural convection.•+45° perforated TIM-PS have a significant impact on the amelioration of efficiency.•Innovative natural convection FPC reach a thermal efficiency more than 60%. The flat plate solar air collector operating in the mode of free convection is an essential element, which contributes to make easier the valorization of solar energy in the residential and industrial sectors. The existing FPCs suffer from comparatively low efficiency and high losses. Being efficient, inexpensive and simple to manufacture, their importance has been increased by the recent intensification of attempts to maximize the profitability of solar energy. To address this challenge, this paper is a numerical investigation of an innovative design and manufacturing approach of a FPC operating with natural convection. A new configuration of FPC, including transparent insulation material parallel slats (TIM-PS), is proposed and investigated. A thorough numerical investigation has been carried out to evaluate the contribution of the TIM-PS in the improvement of the air heating collector performance. The influence of slats’; number, angle of inclination and geometry on the FPC’s performance are studied. This CFD survey yielded the highest optimized and most cost-effective configuration for a vertically mounted collector with seven perforated TIM-PS inclined at +45°. The innovative facade collector can achieve a thermal efficiency around 60% with keeping the lightweight of the collector and the low cost. The peculiarity of this result lies in the combination of perforated and tilted TIM-PS that are investigated in our new study. These results introduce a new design of solar air heater operating in a natural convection mode, designed to be adapted to a range of geographical locations and sunlight conditions.