Enter any 3 values (cooling-water flow rate, heat load, specific heat, and temperature difference) to calculate the missing one. The “cooling water consumption” result is a flow rate (for example, m³/s or gpm).

Cooling Water Consumption Calculator

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Enter any 3 values to calculate the missing variable




Preset density: 998.2 kg/m³


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Cooling Water Consumption Formula

The following formula is used to calculate the required cooling-water volumetric flow rate for a given heat load, fluid specific heat, fluid density, and temperature difference.

\dot{V} = \frac{H}{\rho \, c \, \Delta T}

Variables:

  • V̇ is the cooling-water volumetric flow rate (m³/s)
  • H is the heat load (kW)
  • ρ is the fluid density (kg/m³)
  • c is the specific heat capacity of the fluid (kJ/kg·°C)
  • ΔT is the temperature difference between outlet and inlet water (°C)

To calculate the cooling-water flow rate, divide the heat load by the product of density, specific heat capacity, and the temperature difference. (If you omit density, H/(c·ΔT) gives a mass flow rate in kg/s.) To convert a flow rate into a total volume “consumed,” multiply by a time period (for example, m³/h × hours = m³).

What is Cooling Water Consumption?

Cooling water consumption refers to the amount of cooling water needed to absorb and remove heat from a system or process. In many engineering calculations, this is expressed as a required flow rate (such as m³/h or gpm) rather than a one-time volume, unless a specific operating time is stated. This is commonly used in industrial applications, HVAC systems, and power plants where water is used as a cooling medium to maintain optimal operating temperatures.

How to Calculate Cooling Water Consumption?

The following steps outline how to calculate the Cooling Water Consumption.


  1. First, determine the heat load (H) in kilowatts.
  2. Next, determine the specific heat capacity (c) of the cooling fluid (for water it is about 4.18 kJ/kg·°C near room temperature).
  3. Next, determine the cooling-fluid density (ρ) in kg/m³ (for water it is about 998 kg/m³ near 20°C).
  4. Next, determine the temperature difference (ΔT) in degrees Celsius.
  5. Finally, calculate the cooling-water flow rate using the formula V̇ = H / (ρ · c · ΔT).
  6. If you need a total volume, multiply the flow rate by the operating time (for example, m³/h × hours).
  7. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Heat Load (H) = 500 kW

Specific Heat of Water (c) = 4.18 kJ/kg°C

Temperature Difference (ΔT) = 10°C