Calculate film coefficient, heat transfer rate, contact area or temperature difference from the other three values, in W/m²K or BTU/hr ft²°F.

Solve q = h × A × ΔT for the film coefficient.

Convection model with uniform or averaged film coefficient. Heat rate and temperature difference use the same sign convention. Btu means International Table Btu.

A temperature difference, not an absolute temperature.

Related Calculators

Film Coefficient Formula

h = q / (A × ΔT)

Variables:

  • h is the film coefficient (W/m²K)
  • q is the heat transfer rate (W)
  • A is the heat-transfer surface area (m²)
  • ΔT is the surface-to-bulk-fluid temperature difference (K)

To calculate the film coefficient, divide the heat transfer rate by the product of the heat-transfer surface area and the surface-to-bulk-fluid temperature difference.

What is a Film Coefficient?

A film coefficient, also known as a convective heat transfer coefficient, relates the heat rate at a fluid–surface interface to surface area and the surface-to-bulk-fluid temperature difference. It depends on fluid properties, flow conditions and geometry. The film coefficient is used in calculations involving heat exchange in systems such as radiators, boilers, and heat exchangers. It is a crucial factor in the design and operation of many industrial processes.

How to Calculate Film Coefficient?

The following steps outline how to calculate the Film Coefficient.

  1. First, determine the heat transfer rate (q) in watts (W).
  2. Next, determine the heat-transfer surface area (A) in square meters (m²).
  3. Next, determine the surface-to-bulk-fluid temperature difference (ΔT) in Kelvin (K).
  4. Next, gather the formula from above: h = q / (A * ΔT).
  5. Finally, calculate the Film Coefficient (h) in watts per square meter Kelvin (W/m²K).
  6. After inserting the variables 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 transfer rate (q) = 120 W

heat-transfer surface area (A) = 5 m²

surface-to-bulk-fluid temperature difference (ΔT) = 10 K