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
| Symbol | Name | Unit | Si Unit | Imperial Unit |
|---|---|---|---|---|
| LMTD | Log Mean Temp Diff | K | K | °F |
| ΔT₁ | Temp Diff at End 1 | K | K | °F |
| ΔT₂ | Temp Diff at End 2 | K | K | °F |
Common questions
- What is the Log Mean Temperature Difference formula?
- Effective temperature difference for heat exchangers. It sits under Heat Transfer, Thermo engineering in the EngiRef reference.
- What do the symbols in the Log Mean Temperature Difference formula mean?
- In Log Mean Temperature Difference, LMTD is log mean temp diff in K; ΔT₁ is temp diff at end 1 in K; ΔT₂ is temp diff at end 2 in K.
- When does the Log Mean Temperature Difference formula apply?
- Log Mean Temperature Difference holds under this condition: Counter-flow or parallel-flow heat exchanger.