Calculator · Thermal Engineering
LMTD Heat Exchanger
Parallel and counterflow LMTD from known outlets, verified against capacity rates and conductance.
Inputs
Known outlets are checked against both stream energy balances and UA × LMTD; inconsistent specifications are refused.
Results
Heat-transfer rate Q̇
50 kW
Hot stream → cold stream
| Hot outlet | 350 K |
|---|---|
| Cold outlet | 350 K |
| Exchanger effectiveness εHX | 0.5 |
| NTU | 1 |
| Cmin / Cmax | 1000 / 1000 W/K |
| Capacity ratio Cr | 1 |
| Maximum duty Qmax | 100 kW |
| Terminal ΔT₁ | 50 K |
| Terminal ΔT₂ | 50 K |
| LMTD | 50 K |
Assumptions
- · Steady single-phase streams with constant capacity rates and uniform U; no heat loss or phase change.
- · Coordinate x runs from hot inlet (0) to hot outlet (1).
Explore in the Lab
Open in Heat Exchanger Lab
The same method, stream states and conductance travel to the Lab.
Technical reference
Q̇ = UA × LMTD
Q̇ = εHX Cmin(Th,in − Tc,in)
Qhot = Qcold
Single-phase constant-capacity streams; parallel or counterflow only.
LMTD uses known outlets; no underdetermined state is guessed.