Related Resources: heat transfer

Overall Heat Transfer Coefficients in Heat Exchangers

Heat Transfer Engineering
Engineering Physics

Representative values of the overall heat transfer coefficients in heat exchangers.

Note that the overall heat transfer coefficient ranges from about 10 W/m2· °C for gas-to-gas heat exchangers to about 10,000 W/m2· °C for heat exchangers that involve phase changes. This is very typical since gases have very low thermal conductivities, and phase-change processes involve very high heat transfer coefficients.

Type of heat exchanger U, W/m2 · °C*
Water-to-water 850–1700
Water-to-oil 100–350
Water-to-gasoline or kerosene 300–1000
Feedwater heaters 1000–8500
Steam-to-light fuel oil 200–400
Steam-to-heavy fuel oil 50–200
Steam condenser 1000–6000
condenser (water cooled) 300–1000
Ammonia condenser (water cooled) 800–1400
Alcohol condensers (water cooled) 250–700
Gas-to-gas 10–40
Water-to-air in finned tubes (water in tubes) 30–60†
Steam-to-air in finned tubes (steam in tubes) 30–300†

* Multiply the listed values by 0.176 to convert them to Btu/h · ft2 · °F.
† Based on air-side surface area.
‡ Based on water- or steam-side surface area.