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Calcimator

Cooling Tower Calculator

Calculate cooling range, approach, Merkel number, evaporation rate, and makeup water requirements for cooling tower design.

Inputs

m³/hr
°F
°F
°F
m³/hr

Results

Cooling Range

10 °C

Cooling Approach

5 °C

Merkel Number (KaV/L)1.88
Evaporation Rate5 m³/hr
Makeup Water Required7.17 m³/hr
How to Use This Calculator
  1. Enter the Water Flow Rate in m³/hr — the total circulating water flow through the tower.
  2. Enter the Hot Water Temperature in °C entering the tower and the Cold Water Temperature in °C leaving it. The difference is the Cooling Range.
  3. Enter the Wet Bulb Temperature in °C of the ambient air — this sets the thermodynamic limit. The Approach is how close cold water gets to wet bulb.
  4. Enter the Air Flow Rate in m³/hr through the tower fills.
  5. Review the Merkel Number (KaV/L) — a higher value indicates more efficient mass transfer and a better-performing tower.
  6. Note the Evaporation Rate and Makeup Water Required in m³/hr for water consumption planning and blowdown calculations.

How the result changes with Hot Water Temperature

Hot Water TemperatureCooling RangeCooling Approach
17-13 °C5 °C
355 °C5 °C
5626 °C5 °C
7343 °C5 °C

What each input means

Water Flow Rate
Circulating water flow rate through the cooling tower.
Hot Water Temperature
Temperature of the warm water entering the top of the tower.
Cold Water Temperature
Target temperature of the cooled water leaving the tower basin.
Wet Bulb Temperature
Ambient wet-bulb temperature, which determines the theoretical cooling limit.
Air Flow Rate
Volumetric air flow rate through the cooling tower.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Water Flow Rate = 500, Hot Water Temperature = 40, Cold Water Temperature = 30, Wet Bulb Temperature = 25 = 5 input(s) provided
  2. Calculate Cooling Range
    Cooling Range
    10 = 10
  3. Calculate Cooling Approach
    Cooling Approach
    5 = 5
  4. Calculate Merkel Number
    Merkel Number
    1.875 = 1.875
  5. Calculate Evaporation Rate
    Evaporation Rate
    5 = 5

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