A heat exchanger is the term given to a device that exchanges the heat from one particular fluid over to another. Heat exchanges come with a number of different names as they can be used for a wide variety of different applications. It is important to know precisely what you want when you buy a heat exchanger such as the medium you intend to cool or heat and precisely what you will use it for.
There are three different types of heat exchanger – a Finned Tube heat exchanger, a Shell and Tube heat exchanger and a Plate heat exchanger.
Finned Tube Heat Exchanger
A Finned Tube heat exchanger, also known as an Air Cooled heat exchanger, is able to cool or dry by having a liquid flow into a set of tubes whilst air or gas is pumped over or around the pipes.
In some cases this type of heat exchanger is actually encased within duct work, while at others times they may be completely exposed and have air flowing freely over them. Their extended surface – the fins from which they derive their name – are protruding into the gas/air flow and improving the structure’s ability to transfer heat, and are the reason why they are so efficient.
These heat exchangers are frequently used for the purpose of recovering heat in processes that have exhausted hot gasses. The heat of the gas is exchanged into that of the liquid, in most cases either a thermal oil or simple water. The hot liquid can then be made use of within an application that would otherwise take even more energy to heat up.
These heat exchangers are perfect for chemical applications, steam cooling, grain drying, paper manufacturing, food processing, petrochemical cooling, in-textiles processing and concrete curing.
There is a very varied application range for Finned Tube heat exchangers because air is the world’s most used process fluid.
Shell and Tube Heat Exchanger
This heat exchanger works by passing a gas or a cold or hot fluid through a tube bundle – the name for a series of tubes – that is encased within a big metal shell. The counter flowing gas or fluid is pumped into the shell and then the heat transfer takes place.
This type of heat exchanger is generally utilised in high pressure applications but can also be used in situations where a vacuum condition might need a structure that is able to deal with high stresses.
The containment of a shell and tube is the aspect that makes it more appropriate for hot gasses than is the case with a finned tube bank, especially with noxious gases that can be hazardous to health or cannot be released into the atmosphere.
This heat exchanger has many common applications in the chemical, gas and oil industries.
Plate Heat Exchanger
This heat exchanger type works by having fluids pass through a number of plates that have been compacted together. They are often used for liquid to liquid applications including the hot process water containing contaminants or chemicals that is used to heat up cold mains water and offer clean hot water.
Heat exchangers can suit an array of requirements but it is important to understand which type would best suit your needs.