Optimizing Thermal Efficiencies of Double-Pass Cross-Corrugated Solar Air Heaters on Various Configurations with External Recycling

The effect of external-recycle operations on the thermal performance double-pass cross-corrugated solar air heaters (SAH) under different operating conditions was investigated experimentally and theoretically. Additionally, simultaneous ordinary equations were solved analytically for each proposed configuration. Four recycling types are introduced improving with external recycle processes, which expected to enhance heat transfer coefficient a convective turbulent flow between absorber in present study. Using operations, two processes conducted sequentially: first flowed over sinusoidal corrugated plate then back later transverse bottom plate. Improved device achieved due doubled area plate, from both enhanced intensity. Theoretical predictions experimental results indicated that ratio increased SAH efficiency all designs. show higher four configurations using wavelike plates compared those single-pass flat-plate up maximum 133% (from 0.301 0.703) increment. optimal examined same working dimensions operational conditions. best configuration lengthened pathway velocity within collector; thus, rate accomplished. evaluation increments power consumption heat-transfer enhancement together determined design based an economic consideration across various devices.