Overall Heat Transfer Coefficient

Written by Jerry Ratzlaff on . Posted in Thermodynamics

Overall heat transfer coefficient, abbreviated as 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

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

Where:

\(\large{ U }\)  = overall heat transfer coefficient 

\(\large{ A }\) = contact area for each fluid side

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

\(\large{ A_2 }\) = contact area for the other fluid

\(\large{ dx }\) = wall thickness

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

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

\(\large{ k }\) = thermal conductivity of the material

 

Tags: Equations for Heat Transfer Equations for Heat