Improved Thermal Efficiency of a Double-Pass Solar Air Heater Using Turbulators on the Bottom Surface of the Absorber Duct

The device that uses the energy from the sun to heat air is a solar air heater (SAH). However, its slow heat transmission rate frequently limits its efficiency. To increase thermal performance, this study proposes modifying the traditional solar air heater (SAH) of double pass by adding an improved absorber duct with a turbulator. Within SAH of double-pass (DPSAH), the absorber plate is exposed to air on both its bottom and top surfaces, increases heat transfer rate compared to a single-pass system. This study introduces a novel DPSAH design that incorporates an improved absorber duct and perforated rib type turbulators to improve thermal performance. This design aims to enhances the rate of heat transfer while minimizing drop in pressure. By disrupting the laminar sublayer on the absorber plate, the turbulators promote turbulent flow, causes heat transfer enhancement. The perforations in the ribs further reduce pressure drop, making system more efficient.