Performance enhancement of air conditioner in hot climate by condenser cooling with cool air generated by direct evaporative cooling

This research studied the direct evaporative cooling technique for generating cool air in hot–dry and hot–humid climates. For direct evaporative cooling, three parameters affected the air temperature: feedwater temperature, wet-bulb temperature, and mass ratio of feedwater to circulating air were investigated. When the feedwater temperature was lower than the wet-bulb temperature, in a hot-humid climate, an increase in the mass ratio of feedwater to the circulating air decreased the outlet air temperature. Conversely, if the feedwater temperature was higher than the wet-bulb temperature, in a hot-dry climate, a decrease in the mass ratio was needed to reduce the air temperature. The cooled air obtained could be used for condenser cooling of air-conditioner for performance enhancement. According to a 1 TR air conditioner simulation, lower feedwater temperature resulted in higher energy efficiency ratio. High mass ratio, thus, was recommended in the hot-humid climate area whereas less mass ratio was preferable for the hot-dry climate area. The energy efficiency ratios of the unit with direct evaporative cooling for hot–dry and hot–humid climates ranged from 3.40 to 4.22 and 3.30 to 3.94, respectively, compared to 3.01 for the normal unit. The payback period for the unit with direct evaporative cooling in case of Chiang Mai (hot-humid climate) was around 2.87 year