Variable Speed Cooling Tower Fan

A variable speed drive vsd controls the speed of the high torque direct drive motor for optimal fan operation.

Variable speed cooling tower fan.

Typically the best course of action is to establish a condenser water minimum flow for each pump and vary the condenser water flow based on chiller loading. As such it is a good practice to perform a vibration analysis on the fan and tower assembly as a mechanical resonance may develop at certain speeds. If your facility has variable speed cooling tower fans approach can be reduced by increasing fan speed and therefore taking advantage of more evaporative cooling. Other way is to keep the same cooling tower and install variable frequency drive vfd on cooling tower fans so that we can increase fan speed hence increase air flow to get the required cooling and reduced cooling water supply temperature.

If fan speed and heat load are maintained constant for a given wet bulb temperature approach is constant. The controlled variable is the temperature of the cooling water that is sent back to the process and the manipulated variable is the air flow through the tower which can be changed either by adjusting the speed of variable speed fans or by starting and stopping a number of constant speed fans. The operating cost of cooling tower operation is. When variable condenser water flow and variable speed cooling tower fans are implemented on the same system care must be taken in the development of control strategies.

Vfd controlled cooling tower fans operate over many speeds as opposed to the fans on a single or two speed motor starter. Direct drive motor and vsd packages can be used either in wet or dry cooling towers air cooled condensers acc of air cooled heat exchangers ache. The cooling system usually features cooling towers that house large fan blades. Annual fan electrical energy requirements are calculated for towers with single speed two speed and variable speed fans.

One way is to increase capacity of cooling tower by installing another cooling tower cell. To power the fan it is now possible for a high efficiency permanent magnet direct drive motor to be coupled directly to the fan. Vfd controlled cooling tower fans operate over many speeds as opposed to the fans on a single or two speed motor starter. As such it is a good practice to perform a vibration analysis on the fan and tower assembly as a mechanical resonance may develop at certain speeds.

Fan energy requirements are determined counter flow and cross flow towers.