Evaluation of the Experimental Performance of an Asphalt Solar Air Collector

Abstract

In this research, the performance of an asphalt solar air collector was experimentally tested and the daily thermal and exergy efficiencies of the collector were analyzed. The sun's radiant energy is absorbed by asphalt and 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. The experimental 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 the increase in daily energy and exergy efficiencies with increasing the air mass flow rate. In addition, results show that as the flow rate increases, the outlet air temperature decreases. The presence of temperature difference 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.

Keywords

• asphalt collector
• air
• solar energy
• efficiency