Forced draft heat exchangers push air through the fins of a tube bundle. The tubes are staggered in an array that forces air to travel around each tube and through the finning material. In most cases the finned tube is made of steel or stainless steel while the fins are applied in aluminium or copper.
There are a wide range of variables to take into account when designing a forced draft heat exchanger. The most critical aspect of any heat exchanger design are fluid or gas properties then input temperature, ambient temperature and the desired output temperature.
Unlike chillers or refrigerators that use the expansion of compressed gases to in effect "pull" or attract heat from a gas or fluid, forced draft fin fan coolers can only achieve a cooling effect to or near the ambient temperature of the units environment. An advantage of this being there are not compressed gases or complex pressure systems other than cooling pressure vessel itself making air cooled heat exchangers simple and robust methods of cooling.
Also known as fin fan coolers, air cooled heat exchangers require no fluid to cool and are ideal for dry or desolate environments but do require lots of space. Another advantage being their shape, square. Most pressure chambers are built as cylinders do to a circles ability to distribute pressure evenly over its entire surface. Square pressure vessels are more difficult to design and manufacture due to this inherent inability to distribute pressure evenly and create critical points of strain. When designing a new process line, factory or train rectangular blocks of coolers are easier to place and do not waste space around their sides. Based on their fin material and environment, air blast coolers can be mounted on top of structures allowing exhaust air clear access upwards.