Heat Exchanger Fundamentals

Heat Exchanger is the equipment in which heat (thermal energy) is transferred from one fluid to another fluid. These fluids are separated from each other with a metallic wall. To affect the exchange of heat, both the fluids must be at different temperatures. Heat will flow from hotter to the colder fluid.

Heat can be used for different purposes like, heating a colder fluid; cooling a hotter fluid; to condense a gaseous fluid; to boil a liquid and so on.

Type of heat exchangers

Although there are different types of This heat, the construction of That's fall mainly into two categories: 1. Shell and; and 2. Plate

1. Shell and Heat Exchangers

This is the most common type of heat exchanger construction and is suitable for high pressure applications. This type of That's consists of a set of, called -bundle, arranged in a shell (pressure vessel). One fluid flows through the, this fluid is called side fluid; and other fluid flows over the, this fluid is called shell-side fluid. side fluid is separated from the shell side fluid by sheet at the end of the. The are welded or press fitted into the sheet to provide a leak tight joint. In the shell, are supported by plates called baffles. These baffles reduce the vibration and direct the shell side fluid over the for increased heat transfer efficiency. Generally Shell are designed by TEMA standard and local and international codes for pressure vessels like, ASME BPVC, PD 5500, AD Merk blatt, etc.

There are mainly three types of shell and heat:

Fixed -sheet That's: A fixed -sheet heat exchanger has straight that are secured at both ends to sheets welded to the shell. The sheet may be welded to channel also. In this type of That's, bundle is fixed and cannot be removed. Hence it is generally used in clean service. In the event of large temperature differential between and shell material, higher longitudinal stresses will be developed in the shell and To reduce these stresses, a flexible element called expansion joint is used on shell.

U- Heat Exchanger: In this type of That's, one -sheet is stationary and it has a bundle of U-shaped. bundle is removable for cleaning purpose. Hence it is used for dirty service on shell side. Because of U-bends, it is very difficult to clean inside of. Hence it is not suitable for dirty service on -side.

Floating -sheet This: In this type of this, one -sheet is stationary and the other is free to float within the shell axially. bundle is removable for cleaning purpose. As Floating -sheet heat exchanger can be cleaned from both and shell side, it can be used for services where both the shell and side fluids are dirty.

2. Plate type heat exchanger

A plate type heat exchanger consists of plates instead of to separate the hot and cold fluids. Because of the larger surface area of the plate, this type of is capable of transferring more heat than similarly sized shell and. This type of used for medium and low pressure applications.