Counter Flow Heat Exchanger Example

In counter flow heat exchangers the fluids enter the exchanger from opposite ends.

Counter flow heat exchanger example. For a parallel flow heat exchanger n 0 and for a counterflow heat exchanger n 1. 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. 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. Two tubes have a liquid flowing in the same direction.

There are three primary classifications of heat exchangers according to their flow arrangement. The counter current design is the most efficient in that it can transfer. A thermoconductive membrane or an open section allows heat transfer between the two flows. 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.

Consider a parallel flow or counterflow heat exchanger consisting of fluid 1 fluid 2 and the wall separating these two fluids. The direction in which the two fluids travel through the heat exchanger can be either parallel flow or counter flow. A cocurrent heat exchanger is an example of a cocurrent flow exchange mechanism. A heat exchanger can have several different flow patterns.

We combine these two types together with an index n to indicate the flow direction of fluid 2. 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.