A shell-and-tube heat exchanger is a class of heat exchanger designs.It is the most common type of heat exchanger in oil refineries and other large chemical processes and is suited for higher-pressure applications. As its name implies, this type of heat exchanger consists of a shell (a large pressure vessel) with a bundle of tubes inside it. One fluid runs through the tubes, and another fluid flows over the tubes (through the shell) to transfer heat between the two fluids. The set of tubes is called a tube bundle, and may be composed of several types of tubes: plain, longitudinally finned, etc.

Tube and heat exchangers have various applications, such as in air conditioning systems, refrigeration systems, and industrial processes that require heat transfer.

The components of a shell and tube heat exchanger can be broken down into the following parts:
1. Shell The shell is the heat exchanger’s outermost part which holds the tube bundle. It is commonly a cylindrical container constructed from steel or other appropriate substances
2. Tubes or Tube Bundle A collection of parallel tubes running along the length of the shell makes up the tube bundle. Depending on the specific use, the tubes can be composed of different materials, such as stainless steel, copper, or titanium. The diameter and thickness of the tubes are also important design parameters.
3. Tube Sheets Tube sheets are sturdy sheets that act as a barrier between the tube bundle and the shell. They commonly construct them using steel and fuse them to the shell to ensure a firm and leak-free closure. They insert the tubes through holes in the tube sheets and either expand or weld them in position.
4. Baffles Plates or rods called baffles regulate the movement of fluid around the tube bundle when placed inside the shell. They either align longitudinally or transversely and enhance the effectiveness of heat transfer.
5. Inlet and Outlet Nozzles The inlet and outlet nozzles serve as the entry and exit points for fluids in the heat exchanger. Technicians usually place these connections at opposite ends of the shell and attach them to the tubes and the shell using flanges or other types of fittings.
6. Expansion Joints Expansion joints are flexible connectors that accommodate the tube bundle’s thermal expansion and contraction. Usually located at the inlet and outlet of the heat exchanger, the engineers construct these joints using metal bellows or other flexible materials.
7. Support Structures Support structures secure heat exchangers in place, providing a stable foundation. They can be temporary or permanent and made from steel or other materials.