Variable Frequency Drives - Heat Loss and Required Air Cooling

Calculate heat loss from variable frequency drives and determine the required air cooling (mass flow and volume flow) needed to maintain safe operating temperatures.

Variable Frequency Drive Heat Loss and Air Cooling Calculator

This tool calculates:

  1. Heat Loss: The power lost as heat in a VFD based on transmitted power and efficiency
  2. Mass Air Flow: Required mass flow of cooling air needed
  3. Volume Air Flow: Required volume flow of cooling air at inlet and outlet temperatures

Key Formulas:

  • Heat Loss (kW): Hloss = Pt × (1 - ηd)
  • Heat Loss (BTU/h): Hloss = Pt × 3412 × (1 - ηd)
  • Mass Air Flow: mair = Hloss / (cp × (tout - tin))
  • Volume Air Flow: qair = (1 / ρair) × Hloss / (cp × (tout - tin))
Calculator

Inputs

Results

Heat Loss-- kW
Heat Loss (Imperial)-- BTU/h
Required Mass Air Flow-- kg/s
Volume Air Flow at Inlet-- m³/s
Volume Air Flow at Inlet (Hourly)-- m³/h
Volume Air Flow at Outlet-- m³/s
Volume Air Flow at Outlet (Hourly)-- m³/h
Power (kW)EfficiencyHeat Loss (kW)Mass Flow (kg/s)Volume Flow @ 20°C (m³/h)Volume Flow @ 40°C (m³/h)
250.951.250.062187.5200
500.952.50.125375400
750.953.750.188562.5600
1000.9550.25750800
250.92.50.125375400
500.950.25750800
750.97.50.37511251200
1000.9100.515001600