A Study on Thermal Effectiveness of Multi-Stages Evaporative Air Cooling

Abstract

The air conditioning system performance is significantly affected by temperature rise which causes continuous increase in electricity consumption and pollution problems to environment. Evaporative cooling systems are characterized by their low energy consumption so that they represent successful potential alternatives to traditional vapor compression air conditioning systems. This study investigates the performance of multi-stages evaporative cooling systems experimentally and theoretically. The experimental set-up is mainly composed of two parts: indirect unit to decrease the air temperature and direct unit to moisturize the air. The system is installed and equipped with temperatures, humidity, and air velocity sensors. The experimental tests were run continuously to monitor the system performance at various weather conditions between  to  in June and July months. A mathematical model for the system components was developed and implemented in the Engineering Equation Solver (EES) program to simulate the performance of multi-stages evaporative cooling systems. The results showed that the heat flux  increases with the increase in the Reynolds number Re of inlet air, velocity fraction  extracted air for sensible cooling, air temperature at the product-in , air velocity at the product-in , and the adiabatic efficiency . But, it is decreasing with increasing the spacing between the heat exchanger plates  and the relative humidity at the product-in . Optimum performance was obtained with very small space between plates which was bout 5mm. Good agreement have been shown between experimental and predicted data, where the  results. Uncertainty of experimental data was within the range 4.14 to 6.15.