Counter Flow Heat Exchanger Example

A heat exchanger can have several different flow patterns.

Counter flow heat exchanger example.

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. 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. For a parallel flow heat exchanger n 0 and for a counterflow heat exchanger n 1.

In counter flow heat exchangers the fluids enter the exchanger from opposite ends. We combine these two types together with an index n to indicate the flow direction of fluid 2. Crossflow parallel flow and counterflow heat exchanger configurations are three examples. One starts off hot at 60 c the second cold at 20 c.

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. 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. 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. There are three primary classifications of heat exchangers according to their flow arrangement.