Log Mean Temperature Difference

ΔTlm = (ΔT1 − ΔT2) / ln(ΔT1/ΔT2). Equal ends return ΔT1 instead of dividing by zero.

Thermal & HVAC

ΔTlm = (ΔT1 − ΔT2) / ln(ΔT1/ΔT2). Equal ends return ΔT1 instead of dividing by zero.

App id: THERM-20. Reference version 1.0.

How to fill it

Fill the inputs. The tool shows the outputs.

On the tool screen, Calc is the working sheet. Presets stores values you reuse. Reference is the formula, assumptions, and provenance below.

Formula

ΔTlm = (ΔT1 − ΔT2) / ln(ΔT1 / ΔT2)

Inputs

Name	Unit
ΔT1	`deltaC`
ΔT2	`deltaC`

Outputs

Name	Unit
LMTD (hero result)	`deltaC`

Diagnose

This tool does not attach diagnose observations.

Assumptions

Counterflow or parallel end differences as you define them.

Provenance

Both end differences must be > 0. Cross-flow F-factor is THERM-21, not here.