Natural Convection Counter-Flow Solar Air Heater

In this study, a natural convection counter flow solar air heater (SAH) was designed and investigated experimentally. The SAH has dimensions; 1.5 m lenght and 1 m width, with wire mesh as absorber. The idea of this novel design in pasive solar air heaters is to minimize heat losses from the front cover of the collector and to maximize heat extraction from the absorber. This was done by directing air to flow between two glazing covers (preheating the air) before returning to pass through the absorber, establishing a counter-flow sitaution in the natural convection SAH. Performance testing of the solar air heater on different clear days in Famagusta, North Cyprus shows that its efficiency increases with increasing mass flow rate for the obtained flow range of 0.0012 to 0.005kg/s. The maximum efficiency of operation obtained was approximately 17% at about 0.005kg/s, also maximum air temperature increase was 46°C at a solar radiation flux of about 950W/m².