Experimental investigation of nocturnal cooling assisted evaporative cooling system.

Nocturnal cooling is an age old technique to cool the structure based on the radiative cooling to the night sky where heat loss by long-wave radiation from one surface to another body at a lower temperature. The nocturnal radiative cooling technique can also cool the water up to 28-30°C in a hot and humid place. This relatively cold water can effectively be used to pre-cool the air in a properly designed finned tube cooling coil unit. A test facility is developed where a finned tube cooling coil unit facilitates cool the air followed by conventional evaporative cooling. Results show that direct evaporative cooler clubbed with cooling coil to pre-cool the air attains the temperature drop of the order of 11°C, almost 4°C higher than conventional evaporative cooling with a batter control of humidity, in a hot and humid environment.