having perforated baffles (baffles open area ratio of 46.8%) on the air flow side of the
absorber plate. A direct performance comparison of the baffled duct and smooth duct solar
air heaters shows that the thermal efficiency of the baffled duct solar air heater is about 22-
33% higher than the smooth duct solar air heater; highest thermal performance advantage is
at the lowest flow rate. The enhancement is attributed to the heat transfer enhancement due …