Question $4.$ Two identical double$-$pipe heat exchangers are available for the heating of an organic

liquid at a given mass flow rate $m,$ from an inlet temperature of $T_i$ to an outlet temperature. Flow

regime is turbulent. Saturated steam at $T_s$ is used as the heating medium flowing through annulus.

Organic liquid flows through the inner tube. In which of the following two cases do you expect a

higher outlet temperature of the organic liquid and why? Discuss in detail and support your discussion

with calculations.

a$)$ Heat exchangers are connected in series;

b$)$ Heat exchangers are connected in parallel.