Log Mean Temperature Difference (LMTD)

Designation

Input

Hot side fluid

Cold side fluid

Inlet temperature T1 °C

Outlet temperature T2 °C

Mass flow rate kg/h

Specific heat capacity Cp kJ/kg·°C

Inlet temperature t1 °C

Outlet temperature t2 °C

Mass flow rate kg/h

Specific heat capacity Cp kJ/kg·°C

Calculation Results

Countercurrent

–

°C

Cocurrent

–

°C

Heat duty Q

–

Countercurrent flow

	Δt₁	Δt₂	Δtₘ (LMTD)
Countercurrent	–	–	–
Cocurrent	–	–	–

Note: LMTD applies to steady-state single-phase or condensing exchangers; it is not valid for systems with phase change and latent heat (evaporators/reboilers), nor for transient analysis. Countercurrent ≥ cocurrent.