Study of performance of heat exchanger using water and sand for zinc roof cooling with automatic water spraying

The purpose of this study is to compare the performance of a heat exchanger using water and sand as a cooling medium to cool the surface of the zinc roof by spraying water automatically. The heat exchanger consists of cooling coil made of 3/4” diameter copper formed the sinusoidal curve and planted 10 cm of depth in 1 x 1 x 0.2 m acrylic container filled with water or sand. Water is automatically sprayed onto the surface of the zinc roof and then flowed into a heat exchanger. Comparing the performance of a heat exchanger using water and using sand shows that they basically have a performance that can lower the water temperature used for spraying onto zinc roofing surfaces. The water-to-water heat exchanger that uses water as a cooling medium is more effective in the morning until noon, while the water-to-sand heat exchanger that uses sand as a cooling medium will be more effective during the day until late afternoon. In general, the water-to-water heat exchanger is more able to lower water temperatures compared to the water-to-sand heat exchanger. This system essentially demonstrates its usefulness and capacity as one of the passive cooling strategies that can lower the zinc roof surface temperature which in turn lowers the indoor air temperature.