ShipCalculators.com

NTU–Effectiveness Method

Effectiveness ε of a heat exchanger from NTU and capacity-rate ratio Cr, for counter-flow and parallel-flow.

Heat transferNTU
Loading calculator…

Formula, assumptions, and limits

εcounter=1eNTU(1Cr)1CreNTU(1Cr)\varepsilon_\text{counter} = \frac{1 - e^{-NTU(1 - C_r)}}{1 - C_r \cdot e^{-NTU(1-C_r)}}
SymbolMeaningUnit
UAUAOverall conductance × areakW/K
CminC_\text{min}Smaller of (m·cp) on each sidekW/K
NTUNTUNumber of transfer units
εεEffectiveness

Source: Kays & London - Compact Heat Exchangers

In short

Effectiveness \u03b5 of a heat exchanger from NTU and capacity-rate ratio Cr, for counter-flow and parallel-flow.

Learn the theory Marine Auxiliary Engines and Generators