Heat exchangers are devices which allow thermal heat energy to be transferred between fluids; the fluids being either liquids or gases. The varied use of heat exchangers can be gauged by the fact that it is used in as small a thing as a PCB to something as wide as a spacecraft. In printed circuit boards it is used to dissipate heat produced when current flows through the circuit. In spacecrafts, it is required to maintain heat to protect man and machine from getting damaged.
There are a lot of criteria to be had while selecting a heat exchanger based on the amount of heat transfer required. A superior quality heat exchanger by AIC Group Canada ensures that proper heat exchange between fluids takes place and the requirement is met.
Surface heat exchangers:
When heat exchange takes place between fluids where they come in contact with each other and are separated after the heat exchange has taken place, such heat exchangers are called direct contact type heat exchangers. When heat transfer takes place between two fluids which are separated by a wall made of good conducting material, such a heat exchanger is called the indirect contact type heat exchanger. Here both the fluids simultaneously flow inside the heat exchangerand are also called the surface heat exchangers. These are the most popular ones used in industries and are known by the generalized term of heat exchangers.
Types of surface heat exchangers:
This category of surface heat exchangers are designed as shell and tube types, flat plate types, plain tubular types or the extended fin types of heat exchangers.
Tubular types- The fluid passes through tubes for heat transfer to take place. Popular among the tube types is the shell and tube heat exchanger. In a shell and tube heat exchanger, the fluid whose heat transfer has to take place is passed through a tube and the other fluid is passed on the tube enclosed within a shell or capsule. Both the fluids have different starting temperatures to attain heat exchange. One of the fluid passes through the tube entering the shell containing the other fluid. Here the tube may be fixed to the shell called the fixed tube heat exchanger or the tube is not welded to the shell at the rear header end called the floating head tube exchanger.
Plate types-Here plates made of good conducting material are stacked together with the fluids flowing in the gap between the two plates. A proper gasket system ensures that each of the fluid flows through alternative gaps. So the plate acts as a divider and heat transfer between the fluids take place through this plate. This is the most efficient type of heat exchanger and is available as flat plate heat exchanger and the brazed plate heat exchanger.
Various industrial as well as domestic applications of heat exchangers use either the tube types or the plate types depending on the functionality to be achieved. These above two types constitute the majority of all heat exchangers.