The evaporative cooling technique has gained growing attention for use in air conditioning systems. A hybrid evaporative pre-cooled air-conditioning system has been proposed. An indirect evaporative heat exchanger (IEHX) is adopted as a pre-cooling device before the conventional mechanical vapour compression unit. The present work aims to develop a numerical model for the IEHX to study the pre-cooling performance by using the room exhaust air as the working air. A computational model has been developed to investigate the heat and mass transfer in the indirect evaporative heat exchanger. It can be inferred that the evaporative pre-cooling unit is able to reduce the air temperature and condense water through the IEHX. Consequently, the hybrid evaporative pre-cooled air-conditioning system is able to achieve a potential energy saving due the pre-cooling effect and the improvement of the chiller’s efficiency.
Keywords Indirect evaporative cooling, Air-conditioning, Mathematical model, Heat and mass transfer