Counter Flow Heat Exchanger Example

In the parallel flow arrangement of figure 18 8 a the hot and cold fluids enter at the same end flow in the same direction and leave at the same end.

Counter flow heat exchanger example.

Consider a parallel flow or counterflow heat exchanger consisting of fluid 1 fluid 2 and the wall separating these two fluids. In parallel flow heat exchangers the two fluids enter the exchanger at the same end and travel in parallel to one another to the other side. Two tubes have a liquid flowing in the same direction. One starts off hot at 60 c the second cold at 20 c.

There are three primary classifications of heat exchangers according to their flow arrangement. The simplest heat exchanger is one for which the hot and cold fluids move in the same or opposite directions in a concentric tube or double pipe construction. A thermoconductive membrane or an open section allows heat transfer between the two flows. In a shell and tube heat exchanger coolant usually flows through the central tube core to cool hot oil water or air which passes over and around the tubes.

A heat exchanger can have several different flow patterns. The counter current design is the most efficient in that it can transfer. A counterflow heat exchanger will require less heat exchange surface area than a parallel flow heat exchanger for the same heat transfer rate and the same inlet and outlet temperatures for the fluids. We combine these two types together with an index n to indicate the flow direction of fluid 2.

A cocurrent heat exchanger is an example of a cocurrent flow exchange mechanism. In counter flow heat exchangers the fluids enter the exchanger from opposite ends.