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ExCoil

Air-cooled condenser coils

Air-cooled condenser coil design software

Calculate heat rejection, subcooling, outlet refrigerant state and pressure drop for finned-tube condenser coils. The model splits the coil into desuperheating, condensing and subcooling zones and reports whether your target is really met.

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Calculator included in the free plan · The calculator interface is available in English and Portuguese.

3D model of a finned-tube condenser coil with hot gas inlet and liquid outlet generated by ExCoil

Real application screenshot

What it calculates

  • Rating and sizing modes with the rating airflow preserved
  • Desuperheating, two-phase condensing and subcooling zones by area
  • Outlet refrigerant enthalpy and phase from real properties
  • Refrigerant pressure drop by zone and saturation drop warnings
  • Deficit reported separately from the energy balance when the target is not reached
  • Multiple circuits and liquid-line header position chosen by the user

Results and deliverables

  • Heat rejection, achieved subcooling and outlet phase
  • Zone area fractions and outlet air temperature
  • Air and refrigerant pressure drop, saturation drop
  • PDF report, CSV/JSON (Professional); 3D, STL and STEP (Enterprise)

How the condenser model works

ExCoil uses a moving-boundary cross-flow model averaged over the zones. Single-phase enthalpies come from CoolProp superheated and subcooled grids (piecewise cp = dh/dT) instead of a constant saturation cp, which keeps the desuperheating duty within about 0.2 % of the reference for the main refrigerants.

  • Three-zone moving-boundary cross-flow model
  • Wang–Chi–Chang air side with Schmidt fin efficiency
  • Real superheated and subcooled refrigerant enthalpy grids
  • Wall resistance and fouling included
  • Return-bend pressure drop by Domanski–Hermes

Know the limits

  • Refrigerants without a superheated/subcooled grid fall back to constant cp, and the report says so.
  • Fan curves are not modelled; airflow is an input.
  • Ratings for catalogues require laboratory validation.

Frequently asked questions

Does ExCoil calculate subcooling in an air-cooled condenser?

Yes. The subcooling zone is solved explicitly and the achieved subcooling is reported together with the outlet phase.

What happens if the condenser is undersized?

The result is marked as not meeting the target and the capacity deficit is shown separately, instead of being hidden in the energy balance.

Is the refrigerant pressure drop included?

Yes, for tubes and return bends, with the corresponding drop in saturation temperature.

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