Overall Heat Transfer Coefficient

Written by Jerry Ratzlaff on . Posted in Thermodynamics

Overall Heat Transfer Coefficient

Overall heat transfer coefficient ( \(U\) ) is the heat transfer between items like walls in buildings or across heat exchangers for the conduction within materials.

Overall Heat Transfer Coefficient Formula

\(  \frac{ 1 } { U \;\dot\;\; A }   \;=\;   \frac{ 1 } { h_1 \;\dot\;\; A_1 }  \;+\;    \frac{ dx } { k \;\dot\;\; A }   \;+\;   \frac{ 1 } { h_2 \;\dot\;\; A_2 }    \)

Where:

\( U \)  = overall heat transfer coefficient 

\( A \) = contact area for each fluid side

\( h_1 \) = individual heat transfer convection coefficient for one of the fluids

\( h_2 \) = individual heat transfer convection coefficient for the other fluid

\( A_1 \) = contact area for one of the fluids

\( A_1 \) = contact area for the other fluid

\( k \) = thermal conductivity of the material

\( dx \) = wall thickness

 

Tags: Equations for Heat Transfer Equations for Heat