Heat Exchangers: Advantages of NTU vs LMTD methods in heat exchanger Design

[recreated]

Hello everyone

Exam tomorrow on thermodynmaics and can only find one advantage for the NTU method of design over the LMTD method which is:

The NTU method does not rely on using an numerical iterative solution to find the outlet temperatures of the heat exchanger, which would be the case if the LMTD method were used to find two outlet temperatures. Thus, the NTU would save much calculation time in this case.

Are there any other significant advantages for the NTU vs LMTD method?

If i get this ques. and answer 100% than it will increase my mark by 5% for this simple theory question so please share your knowledge.

Thank you

 

[Mahub Islam]

The NTU method is more convenient (or at least used to be) than the LMTD method for cases in which outlet temperature(s) are not known. Even though iterative calculations for the LMTD method are not as cumbersome as they used to be without modern computational equipment, the NTU method still provides a useful formalism for thinking about heat exchangers.

Mahbub Islam Peyal
Dept. of ME, BAUST

 

[Ali Rabah]

The C* and effectiveness are useful operating parameter. C* tells whether the flow is balanced (C*=1) or unbalanced (C*<1). effectiveness tells how effective the heat exchanger is.