Optimizing Device Performance of Multi-Pass Flat-Plate Solar Air Heaters on Various Recycling Configurations

Various external-recycle configurations of multi-pass flat-plate solar air collectors were studied theoretically to examine the optimal thermal performance under same working dimension and operation conditions. An absorber plate insulation sheet implemented horizontally vertically, respectively, into an open rectangular conduit conduct a recycling four-pass operation, which device lengthens flow channel increases mass rate within collector, thus, more heat transfer efficiency is obtained. Four types with different patterns introduced expected augment due turbulent convective intensity through four subchannels in present study. Coupling energy balances one-dimensional modeling equations derived by making energy-flow diagram finite element, longitudinal temperature distributions for each subchannel The theoretical predictions show that improved accomplished multiple heating pathways over plate, from turbulence augmentation results as compared without inserting (say downward-type single-pass collector). also configuration Type C study) acts collector leading beneficial design improving heat-transfer increasing resident time Theoretical higher up maximum 115% enhancement comparison device. Examination implementing on well hydraulic dissipated power increment delineated, deliberated suitable respect economic consideration.