Back to Library

Heat Exchanger (LMTD / ε-NTU) Calculator

Size the area (LMTD) or rate an existing unit (ε-NTU) for counter-current, co-current and shell & tube exchangers.

ModuleHeat Exchanger LMTDMethodLMTD / ε-NTUVersion1.0.0

Streams flow in opposite directions — the most thermally efficient arrangement (F = 1).

1

Input Parameters

Calculation Mode

Terminal Temperatures

°C
°C
°C
°C

Duty & Coefficient

kW
W/m²K
m²K/W

optional — 0 for clean

%

over-surface allowance

2

Results

Ready to compute?

Enter your parameters and press Calculate Area

4

Reference Codes & Standards

TEMA (11th Ed.)Governing Code

Standards of the Tubular Exchanger Manufacturers Association

Scope:Mechanical design & nomenclature for shell-and-tube exchangers.
ASME BPVC VIII-1 (2025)Governing Code

Boiler & Pressure Vessel Code, Section VIII, Division 1

Scope:Pressure-part design of exchanger shells, channels & tubesheets.
Bowman, Mueller & Nagle (1940)Governing Code

Mean Temperature Difference in Design — Trans. ASME 62

Scope:Analytical LMTD correction factor F for 1 shell / 2N tube passes.
Literature & Further Reading
  • [1]Kern, D. Q. (1950). Process Heat Transfer. McGraw-Hill — LMTD sizing method.
  • [2]VDI Heat Atlas (2010), 2nd Ed. — thermal design data & correlations.
  • [3]Incropera & DeWitt, Fundamentals of Heat and Mass Transfer — ε-NTU / LMTD.