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# How to simulate makeup water water consumption on cooling tower

Hello, I would like to know if there is any way to simulate the total flow of makeup water necessary on a cooling tower due to the three main types of losses. The inputs would vary as the wet bulb temperature and air flow speeds. Thanks!

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The cooling tower objects have inputs for water evaporation, drift and blow down. See example file CoolingTower:SingleSpeed:MultiCell. See the Engineering Reference for equations used to calculate water usage.

Near the end of the cooling tower inputs are these fields:

CoolingTower:SingleSpeed,
SaturatedExit,           !- Evaporation Loss Mode
,                        !- Evaporation Loss Factor {percent/K}
0.0080,                  !- Drift Loss Percent {percent}
ConcentrationRatio,      !- Blowdown Calculation Mode
3.0000,                  !- Blowdown Concentration Ratio
,                        !- Blowdown Makeup Water Usage Schedule Name


When you run the simulation you should see these report variables in the rdd file:

Output:Variable,*,Cooling Tower Make Up Water Volume Flow Rate,hourly; !- HVAC Average [m3/s]
Output:Variable,*,Cooling Tower Make Up Water Volume,hourly; !- HVAC Sum [m3]
Output:Variable,*,Cooling Tower Make Up Mains Water Volume,hourly; !- HVAC Sum [m3]
Output:Variable,*,Cooling Tower Water Evaporation Volume Flow Rate,hourly; !- HVAC Average [m3/s]
Output:Variable,*,Cooling Tower Water Evaporation Volume,hourly; !- HVAC Sum [m3]
Output:Variable,*,Cooling Tower Water Drift Volume Flow Rate,hourly; !- HVAC Average [m3/s]
Output:Variable,*,Cooling Tower Water Drift Volume,hourly; !- HVAC Sum [m3]
Output:Variable,*,Cooling Tower Water Blowdown Volume Flow Rate,hourly; !- HVAC Average [m3/s]
Output:Variable,*,Cooling Tower Water Blowdown Volume,hourly; !- HVAC Sum [m3]

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