Question

A 1-shell-2-tube pass heat exchanger is made of a steel alloy (thermal conductivity 45.4 W/(m K). It is used to cool distilled water from 34^oC to 29^oC using water which flows inside tubes with an outer diameter of 19 mm and an inner diameter of 16 mm. The number of tubes in the shell is 160 (80 per pass). The mass flow rate of distilled water in the shell is 76180 kg/h. The cold water enters the heat exchanger at 24^oC and leaves at 27^oC. The heat transfer coefficient for the shell is 5250 W/(m² K). As for fouling, the fouling factor for the shell is 0.0001 (m² K)/W and for the fouling factor for the tubes is 0.0002 (m² K)/W. Determine:

(i)        the heat transfer rate                                                                              

(ii)       the required mas flow of cooling water   

(iii)      the correction factor

(iv)      the convection heat transfer coefficient inside the tubes                 

(v)       the overall heat transfer coefficient   

(vi)      the area of the heat exchanger.

Answer 1