evaluation of the experimental performance of an asphalt solar air collector

In this research, the performance of an asphalt solar air collector was experimentally tested and the dailythermal and exergy efficiencies of the collector were analyzed. the sun’s radiant energy is absorbed by asphaltand converted into thermal energy. then, it is transmitted to aluminum pipes buried under the asphalt and,finally, to the air passing through the pipes. a suction fan induces the ambient air to the collector. theexperimental results show that the daily thermal efficiencies at mass flow rates of 0.007 (kg/s) and 0.014 (kg/s)are 11.98 % and 24.10 % and daily exergy efficiencies are 0.34 % and 0.66 %, respectively, showing theincrease in daily energy and exergy efficiencies with increasing the air mass flow rate. in addition, resultsshow that as the flow rate increases, the outlet air temperature decreases. the presence of temperaturedifference between the inlet and outlet of the collector in the last hours of the day, when the sun’s radiation islow, indicates that asphalt acts as a thermal energy storage medium.