Classification Of Heat Exchangers
Heat: is energy in transit from one mass to another because of a temperature difference between the two. A form of energy associated with the motion of atoms or molecules and transferred from a body at a higher temperature to one at a lower temperature. Heat energy will move from a high energy state to that of a lower energy state. The process will continue until a state of equilibrium is reached. Equilibrium is the energy state where the material is at the same energy level as its surroundings.
A heat exchanger is defined as device used to transfer thermal energy (enthalpy) between two or more fluids, between the solid surface and a ...view middle of the document...
In this article, the heat exchangers are classified in heat transfer process. In addition, brief description is provided for each classification along with the selection criteria. The following are the main types:
Shell and Tube Heat Exchangers
These are tubular heat exchangers that are widely used in the industry for a number of reasons. They can be custom designed for virtually any operating conditions and capacity, such as from high vacuums to the ultra-high pressures (over 100 MPa). They are limited only by materials of construction. These exchangers can be designed for the special operating conditions such as heavy fouling, vibration, highly viscous fluids, corrosion, erosion, radioactivity and multi-component mixtures and so on. These are versatile exchangers that are made from broad range of materials (metal and non-metal) and in different sizes. They are widely used as process heat exchangers in chemical industries and petroleum-refining; as condensers, steam generators, oil coolers in the power plants, boiler feed water heaters, refrigeration applications.
The shell-and-tube exchangers are basically non-compact exchangers. The heat transfer surface area to volume ratio ranges from about 50 to 100 meter square. Therefore, they need considerable amount of support structure, space, and capital and installation costs. This explains why they are expensive compared to compact heat exchangers. However, they are more efficient and highly effective in heat transfer.
Compact Heat Exchangers
These heat exchangers are characterized by large heat...