Overall Heat Transfer Calculator

Calculate the overall heat transfer coefficient U from heat duty, exchanger area, and LMTD.

kW
m²
°C

Overall Heat Transfer Coefficient (U)

500.0 W/(m²·K)

U (Imperial)88.05 BTU/(h·ft²·°F)

Overall Heat Transfer Coefficient (U) vs Heat Duty (Q)

Vedi formula →

Formula

## Overall Heat Transfer Coefficient The overall heat transfer coefficient U combines all thermal resistances (convection on both sides, wall conduction, fouling) into a single parameter for heat exchanger design. ### Formula **Q = U × A × LMTD**, therefore **U = Q / (A × LMTD)** Typical U values: water-water: 800-1500 W/(m²·K), gas-gas: 10-40, condensing steam-water: 1000-4000. Low U indicates fouling or poor heat transfer conditions.

Esempio Risolto

A heat exchanger transfers 500 kW with 20 m² area and 50°C LMTD.

  1. 01U = 500 × 1000 / (20 × 50)
  2. 02U = 500000 / 1000 = 500 W/(m²·K)
  3. 03In imperial: 500 × 0.176 = 88.1 BTU/(h·ft²·°F)