Energy
Heat Exchanger Area Calculator
Calculate required heat-transfer area from heat duty, overall heat-transfer coefficient, LMTD and correction factor.
Use a U-value appropriate for the exchanger type, fluids, fouling condition and service.
F
Use 1.00 for ideal counterflow or parallel flow. Multipass and crossflow exchangers may require a correction factor below 1.
Required Heat Transfer Area
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Estimated effective heat-transfer area from the entered thermal duty and temperature driving force.
Required area
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Corrected temperature difference
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Heat flux
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Heat duty
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Overall heat transfer coefficient
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LMTD
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Correction factor
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Method:
Heat-exchanger area is calculated from:
Q =
U × A × F × ΔTlm
Rearranging:
A =
Q ÷
(U × F × ΔTlm)
where:
Q = heat-transfer duty
U = overall heat-transfer coefficient
A = effective heat-transfer area
F = LMTD correction factor
ΔTlm = log mean temperature difference
Corrected temperature difference is:
ΔTcorrected =
F × LMTD
Heat flux is:
Heat Flux =
Q ÷ A
The calculator converts all values internally to watts, W/m²·K and kelvin temperature difference before solving for area.
Temperature differences in °C and K are numerically identical. A temperature difference entered in °F is converted to K using:
ΔT(K) =
ΔT(°F) × 5/9
The calculated area is an estimate based on the entered overall heat-transfer coefficient. Actual exchanger design depends strongly on exchanger geometry, fluid properties, flow regime, fouling resistance, wall resistance, allowable pressure drop, phase change, velocity limits and mechanical design requirements.
U-values can vary substantially between clean and fouled service and between liquid-liquid, gas-liquid, condensing and boiling applications. Final exchanger sizing should therefore use a defensible service-specific U-value and appropriate design margins.