usually be a liquid flowing through the inside of the tubes and air or some other gas flowing outside of the tubes, where the additional heat transfer surface area due to the finned tube, increases the heat transfer rate. For a crossflow fin tube exchanger, the fins will typically be radial fins either circular or square, as shown in the pictures in this section.
Most finned tube heat exchangers are crossflow, using finned tubes somewhat like the upper pictures. For a counterflow or parallel flow fin tube exchanger, the fins should be longitudinal instead of radial, as shown in the lower diagram at the left. Finned tubes may be used as internal tubes in an enclosed heat exchanger, but in many cases with an air heat exchanger, the air flows through an open heat exchanger as shown in the next section, where some typical applications of finned tube heat exchangers are shown and discussed.
Examples of Fin Tube Heat Exchangers
Finned tube heat exchangers are used in a variety of household applications and as industrial
heat exchangers. An air heat exchanger like the evaporator coil for an air conditioning unit is typically a fin tube exchanger like that shown in the diagram at the left. Another common fin tube air heat exchanger is the car radiator, as shown at the right. The purpose of the car radiator is to cool the hot water in the tubes with the air passing through in crossflow. The air conditioner evaporator coil has the purpose of cooling the air passing through it.
A fin tube exchanger can be used as an industrial heat exchanger also. A picture is shown at the left. An application that has seen widespread expansion recently is 'dry cooling' for steam power plants. This consists of using an air cooled condenser instead of a water cooled condenser. Interest in dry cooling for steam power plants has increased because of concern about the amount of water use and thermal effects on water bodies from the traditional cooling systems, 'once through cooling' and 'closed system - cooling tower cooling.'