Performance enhancement of air-cooled chillers with water mist: Experimental and analytical investigation

This paper investigates how water mist evaporative pre-cooling can be applied to air-cooled chillers to improve the chiller efficiency by on-site experimental studies. There is a lack of detailed experimental studies on the application of water mist system on air-cooled chillers. The experiment was conducted on a chiller plant with water mist system in a subtropical climate. The experimental results showed that the dry bulb temperature (DBT) of entering condenser air with water mist pre-cooling could drop by up to 9.4 K from the ambient air temperature, and the approach could be as low as 0.5 K. A thermal effectiveness of up to 0.91 was obtained in using the water mist system. The pre-cooled condenser air enabled a drop of the condensing temperature by up to 7.2 K, and the chiller coefficient of performance (COP) could be improved in varying degrees by up to 18.6%. This study demonstrates that the water mist system coupled to air-cooled chillers is an energy-efficient and environment friendly technique, which has significant potential to improve the efficiency of air-cooled chillers and reduce the electricity demand for the commercial and industrial sector.