Heat Exchanger Quick-Sizer

LMTD method with F-correction and effectiveness-NTU for counter-flow, parallel-flow, cross-flow, and shell-and-tube exchangers.

Exchanger Configuration

Solve for

Hot Stream

Inlet Temp (T_H1)

°C

Outlet Temp (T_H2)

°C

Mass Flow Rate

kg/s

Specific Heat (Cₚ)

J/(kg·K)

Cold Stream

Inlet Temp (T_C1)

°C

Outlet Temp (T_C2)

°C

Mass Flow Rate

kg/s

Specific Heat (Cₚ)

J/(kg·K)

Design Parameters

Overall U [W/(m²·K)]

W/(m²·K)

Results — LMTD Method

Required Area

20.12m²

LMTD (effective)

40.00°C

NTU

1.203

Effectiveness ε

61.2%

Hot duty (Q_H)

292.60kW

⚠ 54.5% imbalance

Cold duty (Q_C)

512.05kW

C_H

8360W/K

C_C

14630W/K

⚠ Hot and cold duties differ by 54.5%. Check that outlet temperatures are consistent with the specified flow rates.

Effectiveness-NTU Summary

C_min

8360W/K

C_max

14630W/K

C_r = C_min/C_max

0.571

Q_max (theoretical)

627.00kW

Reference

LMTD Method

Q = U · A · F · LMTD

F = 1 for counter-flow and parallel-flow. F < 1 corrects multi-pass arrangements (Bowman-Mueller-Nagle).

NTU Method

NTU = U·A/C_min · ε = f(NTU, C_r)

Effectiveness ε = Q_actual / Q_max. C_r = C_min/C_max. Achievable duty = ε · C_min · (T_H1 − T_C1).

Typical U values [W/(m²·K)]: Water-water 1000–2500 · Gas-gas 20–300 · Steam-water 1500–4000 · Oil-water 300–900 · Air cooler 30–60