Performance analysis of a cooling tower system used for cooling hot thermal distillate from a desalination system under severe climatic conditions

The water storage and distribution terminal in a city on the East coast of Saudi Arabia receives very hot potable water from thermal desalination process. The flowrate of water is 800-900 t/h during all seasons with the temperature of water ranging between 44 degrees C-46 degrees C. To lower the temperature of the hot water, cooling towers were installed to cool the water to 38 degrees C and make it suitable for domestic consumption without affecting the water quality. The summer ambient temperatures can reach 47 degrees C during the day with relative humidity up to 45%, while the night time ambient temperatures can exceed 30 degrees C with relative humidity reaching as high as 70%-80%. The cooling towers sometimes fail to achieve the targeted temperature of 38 degrees C during the summer months. This study and evaluation present the findings from one such time period which lasted for several days, when the water could only be cooled to temperatures ranging between 38 degrees C and 40 degrees C. Furthermore, it was found that higher relative humidity results in lower efficiency of the cooling towers.