Impact of Airflow on Evaporative Cooling System by Analysis of Cooling Efficiency

Abstract

This research aims to investigate the impact of airflow on the performance of two evaporative cooling systems—spiral pipe and straight pipe, both used for direct evaporative cooling (DECs). An overview of the procedure was conducted using a rectangular-shaped rice straw (RS) cooling pad where the length is 33 cm, the width is 17 cm, and the thickness is 1.0 cm. It was selected for its abundance as an agricultural byproduct, cost-effectiveness, and natural porosity, which increases evaporation. Low air velocity (1.7 m/s), medium air velocity (2.3 m/s), and high air velocity (4.4 m/s) are the criteria for this investigation. The collected data encompass the inlet dry bulb temperature (DBT), wet bulb temperature (WBT), outlet dry bulb temperature, inlet humidity, outlet humidity, and input air velocity. These measurements evaluate the cooling efficiency of two evaporative cooling systems. The experimental findings are displayed through tables and graphs and are analyzed by established theories. As a result of the research, the spiral pipe consistently achieved higher cooling efficiency than the straight pipe. At low air velocity (1.7 m/s), the spiral cooler attained the average highest efficiency of 33.84%, while the straight pipe cooler reached an average highest efficiency of 29.37%. The main reason behind the high efficiency of spiral pipe is that it has a longer path, a wide surface area for heat exchange, and the presence of turbulent flow in the pipe, which enhances better air-water interaction and improves the evaporative cooling system's cooling efficiency. However, this paper focuses on three experiments; if more data could be collected, the result would be more accurate. It was concluded that if the airflow is low, it enhances cooling efficiency whereas if the airflow is high, it reduces cooling efficiency.