The performance of air conditioning unit drops dramatically whenever the outside air temperature increases above a certain point. This problem is obvious in hot weathered countries like in the Middle East. In hot and humid countries like Malaysia, this problem can be detected whenever the air conditioning condenser unit is put in a hot place such as in the basement car park area. Therefore, it is a challenge for researchers and engineers to come up with new ideas in order to improve the performance of the air conditioning system in situations stated above. The performance of the air conditioning system is dependent on well the condenser rejects heat to the outside environment. The improvement in performance will ultimately saves energy and thus the cost of the overall system.

In the present work, an evaporate cooling system is incorporated to the conventional air conditioning condenser unit, Experiments were conducted and mathematical models are then constructed in order to quantify the improvement in term of heat transfer rate that has been achieved by incorporation of the evaporative cooling system. Hot water is used as the refrigerant and water (in midst form) is sprayed all onto the surface of the condenser tube. The experimental set up is equipped with thermocouples in selected locations on the condenser tube. Temperatures in the selected locations are recorded so that mathematical model can be developed. Reliable mathematical correlations from published literature and textbooks are used in the mathematical modeling. Matlab is used extensively throughout the mathematical modeling.