Theoretical investigation of combining cooling tower and cooling coil with direct evaporative cooler

A theoretical study is developed to examine the feasibility of using the cooling tower and the cooling coil with the direct evaporative cooler in the highest summer temperature in Karbala/Iraq. This is due to the inability of the direct evaporative cooler in reducing the outside air temperature and efficiency reduction in the mechanical vapor compression systems despite its high electrical energy consumption at high temperatures. The water in the cooling tower is cooled to a temperature higher than the outdoor wet-bulb temperature by (3.9 degrees C). The water then passes through the cooling coil where the outdoor air is pre-cooled through it, and the outdoor air temperature decreases by (17 degrees C) without an increase in humidity. Then the pre-cooled air passes through the direct evaporative cooler where its temperature decreases by (10 degrees C) and humidity increases. The temperature of the air leaving this combining system is reduced by (27 degrees C). The results showed that the temperature of the air leaving this combining system is adequate and passes through the comfort zone in the psychrometric chart. The results presented that the cooling tower and the cooling coil alone were unable to reduce the air temperature to reach the comfort zone. A similar observation is noted with the direct evaporative cooler. Therefore, the combining system is considered a more effective alternative to the direct evaporative cooler, and its effectiveness reaches more than 100%. Additionally, it is clean, environmentally friendly, energy efficient, and does not add heat to the surrounding environment in comparison with mechanical vapor compression systems.