Comparison of three single-passage SAHs with different modifications

ABSTRACT: The increasing costs of fossil fuels and the influence of their harmful combustion products on the climate change, which has dramatically been revealed in this century are considered as critical dynamics behind the global search for different suggestions to meet these urgent challenges. In the present work, three different types of solar air heaters (SAHs). One of the collector consist of fins attached to aluminum plate and the other collectors made of two different sizes of aluminum square tubes as absorber plates were experimentally investigated in order to achieve the most efficient design of the proposed SAHs. Experiments were conducted, based on the ASHRAE standards, under Famagusta - Cyprus climatic conditions. The thermal performances of the three collectors were examined over a broad range of operating and design conditions. Results showed that there was no superiority for one collector over the other. The effect of mass flow rate on the performance was different for each SAH. At low mass flow rates it was found that the SAH having 20 x 20 mm square aluminum tubes as absorber plate has the highest efficiency which was calculated as 86%; whereas, the maximum efficiency at higher mass flow rates was obtained in the SAH having finned absorber plate which was 93%. Key words: Solar air heater, Thermal efficiency, Collectors, Temperature, Panels. …………………………………………………………………………………………………………………………