The direction in which the two fluids travel through the heat exchanger can be either parallel flow or counter flow.
Counter flow heat exchanger example.
One starts off hot at 60 c the second cold at 20 c.
We combine these two types together with an index n to indicate the flow direction of fluid 2.
A thermoconductive membrane or an open section allows heat transfer between the two flows.
Two tubes have a liquid flowing in the same direction.
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.
A heat exchanger can have several different flow patterns.
A cocurrent heat exchanger is an example of a cocurrent flow exchange mechanism.
Crossflow parallel flow and counterflow heat exchanger configurations are three examples.
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.
For a parallel flow heat exchanger n 0 and for a counterflow heat exchanger n 1.
There are three primary classifications of heat exchangers according to their flow arrangement.
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.
The counter current design is the most efficient in that it can transfer.
Consider a parallel flow or counterflow heat exchanger consisting of fluid 1 fluid 2 and the wall separating these two fluids.