Most commercial air conditioners utilize air-cooled condensers to condense their refrigerant at high pressure. Usage of outdoor air to cool the condenser can lead to loss of efficiency of the air conditioner in extreme hot weather. In countries with hot and humid climate like Bangladesh, a lot of condensate water accumulates in the evaporator of the air conditioner which can be used to cool the incoming outdoor air to the condenser to improve its thermal performance. An evaporative media pad placed before the air intake of the condenser, soaked with the condensate water can cool the intake air while the condensate evaporates. This system can easily be implemented without substantial change to the existing design of the commercial air conditioners and without consuming any additional energy. For this paper such a system was employed to a split air conditioner and the performance of the air conditioner was compared between before and after the implementation of the system. It was found that the air conditioner showed up to 20 % increase in performance while utilizing the system. This paper also explores the amount of condensate water produced and consumed by the evaporative system throughout different outdoor temperatures and humidity and compares the performance of the air conditioner at such conditions. Results show that at around 60 % relative humidity the system performs the best because at too low humidity not enough condensate is produced to cool the air and at too high humidity the condensate does not evaporate easily causing less cooling. • Condensate water is reused for evaporative cooling of condenser intake air. • The proposed system improves air conditioner COP by up to 20 %. • No additional energy input or system modification is required. • Performance enhancement strongly depends on ambient relative humidity. • Optimal system operation occurs at approximately 60–70 % relative humidity.
Rafid et al. (Wed,) studied this question.