Heat Exchanger

The heat exchanger is equipment that is used as a medium for exchanging heat in two or more fluids. Selection of heat exchanger type is generally based on several things such as thermal efficiency, cost, and coverage of changes in temperature.

Heat exchangers are generally classified by type of flow and type of construction. The type of flow can be parallel flow as shown in Figure 1, counter flow as shown in Figure 2, cross flow as shown in Figure 3.

Figure 1: Heat Exchanger with Parallel Flow

Figure 2: Heat Exchanger with Counter Flow

Figure 3: Heat Exchanger with Cross Flow

The type of simple heat exchanger is double-pipe heat exchanger (DPHE). DPHE construction is shown in Figure 1 and Figure 2. In this heat exchanger type, each fluids both hot fluid and cold fluid will flow through a pipe.

Another type is shell and tube heat exchanger (STHE) as shown in Figure 4. Classification of this type is based on the number of shell and tube. In this heat exchanger type, baffles are utilized to enhance the heat transfer that occurs. This increase is caused by turbulent flow which is created by baffles.

Figure 4: Shell and Tube Heat Exchanger (STHE)

STHE is generally used when the fluid pressure is high enough and need large changes in fluid temperature. If the temperature change that is needed is not large, the type of plate heat exchanger (PHE) can be used. But the initial fluid temperature and pressure should not be too high. It is intended to maintain the function of rubber gasket that can be damaged at high temperatures.

In addition, there are also types of direct-contact heat exchanger. In this type, hot and cold fluid will mix directly to experience changes in temperature. By using this heat exchanger, big differences of fluid temperature can be obtained.