TYPES OF HEAT EXCHANGERS
Figure 3 Parallel Flow Heat Exchanger
Counter flow, as illustrated in Figure 4, exists when the two fluids flow in opposite
directions. Each of the fluids enters the heat exchanger at opposite ends. Because the
cooler fluid exits the counter flow heat exchanger at the end where the hot fluid enters
the heat exchanger, the cooler fluid will approach the inlet temperature of the hot fluid.
Counter flow heat exchangers are the most efficient of the three types. In contrast to the
parallel flow heat exchanger, the counter flow heat exchanger can have the hottest cold-
fluid temperature greater than the coldest hot-fluid temperatue.
Figure 4 Counter Flow Heat Exchange