Heat Exchanger, Coil & Radiator Manufacturing worked example

Heat Transfer Area at 98% area yield factor: a worked example

This scenario runs the heat transfer area calculation on the strong side: 98% area yield factor, with every other input held at its documented default. Use it before quoting or releasing a build when you need a quick surface area check against a drawing, selection sheet, or customer duty requirement.

The inputs for this scenario

  • Active tubes or passages in the core: 500 count (unchanged)
  • Theoretical heat transfer area per tube: 0.8 sq ft / tube (unchanged)
  • Area yield factor (good area after fouling/derating): 98 % (raised for this scenario; the documented default is 85)

Working through the calculation

  • Applying the documented formula (Required gross heat transfer area = active tubes or passages × theoretical area per tube ÷ area yield factor) to the inputs above produces each figure below.
  • At this operating point the engine returns 408 sq ft for required gross heat transfer area, the number this scenario is built around.
  • At this operating point the engine returns 400 sq ft for theoretical tube area.
  • At this operating point the engine returns 8.16 sq ft for area allowance.
  • At this operating point the engine returns 98 % for area yield factor.

How this compares with the baseline

  • Against the tool's baseline example, where area yield factor sits at 85% and the headline result is 471 sq ft, this scenario comes in 13.27% below the baseline at 408 sq ft.
  • Use it when converting a thermal sizing into a tube-count specification, quoting a new core, or validating that an as-built bundle has enough surface to hold its rated duty. Treat this as a target state: the delta against the baseline quantifies what the improvement is worth before you commit to chasing it.

Results at a glance

  • Required gross heat transfer area: 408 sq ft (headline result)
  • Theoretical tube area: 400 sq ft
  • Area allowance: 8.16 sq ft
  • Area yield factor: 98 %

Run it with your numbers

  • Every input above is editable in the live Heat Transfer Area calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.