Caloric temperature

Caloric temperature Tc , tc :

Caloric Temperature is supposed to be the "correct" average temperature between inlet and outlet of a stream.

 

When using the stream properties at that temperature one should, in theory, obtain those film coefficients (hi and ho) for tube and shell sides that would result in the correct U value of the exchanger.

Tc=T2+Fc(T1-T2) tc=t1+Fc(t2-t1)

The caloric fraction Fc can be obtained fromexperimental results [3 by computing Kc from Uh and Ucand ∆tc/∆th for the process conditions. If neither of theliquids is very viscous at the cold terminal, say not morethan 1.0 centipoise, if the temperature ranges do notexceed 50 to 100o F, and if the temperature difference isless than 50o F, the arithmetic means of T1and T2 and t1nadt2 may be used in place of Tc and tc for evaluating thephysical properties.

Caloric Temperature Correction Factor Fc