Cooling Towers

CoolingTower:SingleSpeed CoolingTower:TwoSpeed CoolingTower:VariableSpeed:Merkel CoolingTower:VariableSpeed

Used in:   Condenser loop, supply side

Cooling towers are placed on the supply side of condenser loops. The cooling tower is modelled as a counter-flow heat exchanger with options for single-speed, two-speed or variable-speed fan. Specifically, 4 types of cooling tower are available:

• Single Speed
• Two Speed
• Variable Speed (Merkel)
• Variable Speed

Cooling towers here are “wet” and consume water through evaporation, drift, and blow-down. The model can be used to predict water consumed by the towers.

The cooling tower seeks to maintain the temperature of the water exiting the cooling tower at (or below) a set point. The set point schedule value is defined by the condenser loop outlet setpoint manager:

The Condenser Loop Tutorial includes a useful description of cooling tower operating principles and the Cooling tower dialog

The schematic diagrams below (reproduced with permission from CIBSE) illustrate the various types of Direct & Indirect Heat Rejection used in cooling towers. The condenser process takes the fluid from saturated vapour (point 5) to saturated liquid (point 6) on the graph below.

Direct & Indirect Heat Rejection (CIBSE Guide B Table 4.10)

Induced Draft Cooling Tower (CIBSE Guide B Table 4.22)