TYPES OF HEAT EXCHANGERS
Types of Heat Exchangers
Figure 2 Plate Heat Exchanger
Because heat exchangers come in so many shapes, sizes, makes, and models, they are categorized
according to common characteristics. One common characteristic that can be used to categorize
them is the direction of flow the two fluids have relative to each other. The three categories are
parallel flow, counter flow and cross flow.
Parallel flow, as illustrated in Figure 3, exists when both the tube side fluid and the shell
side fluid flow in the same direction. In this case, the two fluids enter the heat
exchanger from the same end with a large temperature difference. As the fluids transfer
heat, hotter to cooler, the temperatures of the two fluids approach each other. Note that
the hottest cold-fluid temperature is always less than the coldest hot-fluid temperature.