Counter Flow Vs Cross Flow
Counter Flow Cooling Tower
Counter flow cooling towers are fitted with an induced draught fan on the top and are directly mounted on the motor. The fan induces the ambient air into the tower to draft it upward. As a result, the speed of exhaust air is much higher than the air that enters. These results in low pressure drop and also lower circulation.
The cooling tower performs on counter flow mechanism, in which the air drafts vertically upwards through the fillings/packing, while the water splashes downwards. Counter flow design is more suitable for the application, where cold water temperature is critical.
One of the main advantages of counter flow design is that the coldest water contacts the driest air resulting in the maximum tower performance. Being an enclosed device, a counter flow cooling tower eliminates the possibility of sunlight exposure of water. This minimizes the possibility of growth of algae.
Cross Flow Cooling Tower
Unlike counter flow cooling tower, air flows through the fills horizontally and water falls down vertically. Cross flow cooling tower are filled by splash type fillings, which are suitable for the application where water has higher suspended particles. Non compatibility of film type fills is a drawback of cross flow type cooling towers.
Another disadvantage of cross flow cooling tower is that some of the air drawn by the fan leaves cooling tower unutilized, which leads to the inefficiency of the cooling tower.
In many cases cooling tower motor is mounted on the side, which results in high noise level and causes inconvenience to the nearby areas. Water spillage is also another problem with the cross flow cooling tower.