This is a HVAC chilled water system cooling tower fan for a large chilled water system. Four large cooling towers for two chiller plants in a data center. Data center cooling systems generally are redundant not only for emergency situations but also for maintenance. The cooling tower fans typically have vibration switches installed in the cooling tower fan assembly to shut the fan off in the event of too much vibration. A fan this large (approximately 6 foot diameter) needs to be balanced to prevent vibration that could possibly shake the cooling tower apart and create a safety hazard for workers. The cooling tower fan is driven by a variable frequency drive that ramps the cooling tower fan up and down depending on demand.
Depending on the load factors and the control of the system the fan will ramp up and down based on load or demand. The fan pulls air through the cooling tower and across the louvers where the water falls. As the water falls along the louvers the air is pull across the water where a heat exchange process takes place by the process of evaporation. the water, with the heat removed for it