EngiRef / Thermodynamics Engineering Formula

Log Mean Temperature Difference

Log Mean Temperature Difference: Effective temperature difference for heat exchangers. A Heat Transfer formula in thermodynamics engineering.

Heat Transfer

Specification

Name
Log Mean Temperature Difference
Discipline
thermodynamics
Category
Heat Transfer
LaTeX
LMTD = \frac{\Delta T_1 - \Delta T_2}{\ln(\Delta T_1 / \Delta T_2)}
Description
Effective temperature difference for heat exchangers
Conditions
Counter-flow or parallel-flow heat exchanger
Can solve for
LMTD
Tags
lmtd, heat, exchanger, temperature, difference

Variables

Variables for Log Mean Temperature Difference
SymbolNameUnitSi UnitImperial Unit
LMTDLog Mean Temp DiffKK°F
ΔT₁Temp Diff at End 1KK°F
ΔT₂Temp Diff at End 2KK°F