Heat Exchanger Effectiveness-NTU Method

Section 11.4

The Effectiveness-NTU method is an heat exchanger analysis method like the log-mean temperature analysis method but doesn't require knowing the outlet temperatures.

NTU stands for number of mass transfer units.

After defining heat exchanger effectiveness () the following equations can be made:

Equation 11.20 (Hot fluid):

Equation 11.21 (Cold fluid):

Where subscripts and refer to hot and cold, subscripts and refer to inlet and outlet, is the heat capacity rate, is either or - whichever is smaller, and is temperature.

Table 11.3 and Table 11.4 - Heat Exchanger NTU relations provide relationships between effectiveness and NTU (number of mass transfer units).

ME3304 S24 Lecture Note (6) Heat Exchanger, 12C - 2nd Class.