Shell and Tube Heat Exchangers are one of the most popular types of exchanger due to the flexibility the designer has to allow for a wide range of pressures and temperatures.A shell and tube exchanger consists of a number of tubes mounted inside a cylindrical shell.There can be many variations on the shell and tube design. Typically, the ends of each tube are connected to plenums (sometimes called water boxes) through holes in tubesheets.Two fluids can exchange heat, one fluid flows over the outside of the tubes while the second fluid flows through the tubes. The fluids can be single or two phase and can flow in a parallel or a cross/counter flow arrangement.
The shell and tube heat exchanger is made up of a bundle of parallel heat exchanger tubes held in place with tube sheets and placed into a shell. The heat exchange always takes place between two fluids through the heat exchanger tube wall. There are quite a variety of flow options for shell and tube heat exchangers, as discussed in the following sections. In all of the configurations for shell and tube heat exchangers, one fluid passes through the tubes (the tube side fluid) and the other passes through the shell (the shell side fluid). The choice of shell and tube heat exchanger configuration affects the overall heat transfer coefficient and thus also affects the rate of heat transfer and the heat exchanger tube surface area needed.
The shell and tube exchanger consists of four major parts:
Front Header – this is where the fluid enters the tubeside of the exchanger. It is sometimes referred to as the Stationary Header.
Rear Header – this is where the tubeside fluid leaves the exchanger or where it is returned to the front header in exchangers with multiple tubeside passes.
Tube bundle – this comprises of the tubes, tube sheets, baffles and tie rods etc. to hold the bundle together.
- Shell – this contains the tube bundle.
Applications and uses
The simple design of a shell and tube heat exchanger makes it an ideal cooling solution for a wide variety of applications. One of the most common applications is the cooling of hydraulic fluid and oil in engines, transmissions and hydraulic power packs. With the right choice of materials they can also be used to cool or heat other mediums, such as swimming pool water or charge air. One of the big advantages of using a shell and tube heat exchanger is that they are often easy to service, particularly with models where a floating tube bundle (where the tube plates are not welded to the outer shell) is available.