2. Log Mean Temperature Difference (LMTD) is best suited when the temperature difference is known.
The Effectiveness-NTU is best used when the surface area is known.

3. Assumptions for HEX analysis
Steady-state, steady flow
No heat generation in the HEX
Negligible ΔPE, ΔKE
Adiabatic processes
No phase change
Constant specific heats and other physical properties.

4. Under these assumptions, the first law of thermodynamics requires that the rate of heat transfer from the hot fluid equals the rate of heat transfer to the cold fluid.

11. Notes

20. Example