Solar photothermic conversion by wasted tire crumbs for water heating under the circular economy perspective

Wasted tires are one of the most harmful wastes and are a challenging environmental problem. This project utilized wasted tire crumbs as thermal energy storage and solar photothermic conversion medium for solar water heating. The functionality of the compacted system has been proven experimentally. A solar collector model is developed comprising an open water flow in a U-shape copper piping immersed in a 0.15-m-wide x 0.08-m-high x 1.0-m-long compartment filled with tire crumbs and covered by a Perspex sheet to permit the penetration of the solar radiation. Three water flow rates of 10, 20, and 30 L/h have been used to investigate the system performance. Measurement results show that the tire crumbs could convert solar energy to thermal energy and transfer it to the water inside the pipe. The system performance shows a mean efficiency of 30.5%, 57.5%, and 73% for the 10, 20, and 30 L/h water flow rate cases. The results show that the waste tires are rich in energy materials for solar photothermic energy conversion and thermal energy storage. It is recommended to extend the study by mixing the crumbs with another sensible or latent thermal energy storage material and evaluate the performance in close loop water flow rate.