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.

夜间冷却（Nocturnal cooling）是一种古老的建筑降温技术，其原理基于向夜空的辐射冷却（radiative cooling）——热量通过长波辐射从一个表面传递到温度更低的物体。在炎热潮湿地区，夜间辐射冷却技术可将水冷却至28-30°C。这种相对低温的水可有效用于经过合理设计的翅片管冷却盘管单元（finned tube cooling coil unit）中预冷空气。研究人员搭建了一套试验装置：翅片管冷却盘管单元先对空气进行冷却，随后采用传统蒸发冷却（conventional evaporative cooling）。结果表明，在炎热潮湿环境下，直接蒸发冷却器（direct evaporative cooler）与冷却盘管结合预冷空气的系统，可使空气温度下降约11°C，相比传统蒸发冷却系统温度降幅高出近4°C，且湿度控制效果更佳。