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Plant Engineering Calculator

Heat Exchanger Fouling Resistance Calculator — Clean vs Dirty U-Value

Calculate added thermal fouling resistance and UA degradation from clean and dirty overall heat-transfer coefficients.

Inputs

Results

Added fouling resistance 0.000417 m²-K/W
U degradation 25.0 %
Clean UA 80.0 kW/K
Dirty UA 60.0 kW/K
UA loss 20.0 kW/K

Formula

Rf=1/Udirty−1/Uclean.

Worked example

A clean U of 800 and dirty U of 600 W/m²-K implies added resistance of about 0.000417 m²-K/W.

Assumptions & limits

  • U-values must use the same area basis and units.
  • This is an observed overall resistance change, not a diagnosis of which side is fouled.

FAQs

What does this Heat Exchanger Fouling Resistance Calculator calculate?

Calculate added thermal fouling resistance and UA degradation from clean and dirty overall heat-transfer coefficients.

Which inputs matter most?

Use measured operating data where possible and keep pressure, temperature, flow, efficiency and tariff inputs on the stated basis. Intermediate outputs make the calculation auditable.

Can I use this for final equipment selection?

Use it for engineering screening and scenario comparison. Confirm final selections against OEM curves, steam/property tables, applicable codes and project design conditions.

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Last updated: 2026-09-17