Theoretical Investigation of an Indirect Evaporative Air Cooling System

In this paper an indirect evaporative cooler theoretically investigated. Because of its low cost and low environment pollution, the indirect evaporative coolers have great potential as an alternative to conventional air conditioning in an arid hot climates such as southern of Libya where the temperature and relative humidity reach 45 º C and 20 % respectively. The present investigated system consists of cooling tower, cross unmixed heat exchanger, air blower, circulating pump, air filter, humidifier, and air duct. The main factors that affect on the temperature output of the system are presented. The affect of air conditions input to the cooling tower and air duct were clarified by solving the control equations using Matlab program. The results show that the air dry bulb temperature directly proportion to the outlet dry bulb temperature, and air input relative humidity notable proportion to the outlet dry bulb temperature. The water flow rate in the cooling tower affect on the outlet air temperature, were as it increases the outlet air temperature decreases. Also the air flow rate through the cooling tower contributes in the outlet air temperature, while the increasing in the air flow rate leads to decreasing in the outlet air temperature. Furthermore as the flow rate of the air inside the air duct increases, the outlet temperature decreases. Moreover investigation proves that the indirect evaporative cooling successfully can be used in the southern of Libya.