A very common heat exchange design is called a shell and tube heat exchanger. The coefficient of heat transfer of each of these devices effects the pace of heat exchange and the surface area of the tubes required to acquire it. Determined by the specific need, and the kind of fluids utilized, there are a number of configurations options that are typically utilized.  You can see that heat exchangers are used in many industrial settings.

Shell and tube heat exchangers, are a metal shell, with parallel tubes inside that are utilized to exchange heat between fluids. The heat exchange always takes place between two fluids through the heat exchanger tube wall. There are many model variants that are utilized to accomplish heat transfer within heat exchangers. 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 particular model that is utilized establishes the heat transfer coefficient and the level at which heat exchange occurs.

The fluids between which heat is exchanged are referred to as the tube side fluid and the shell side fluid.

Other components that are important in this types of heat exchange system are the inlet and outlet nozzles for the tube and shell fluid, as well as tube sheets and baffles that are employed to accelerate the heat exchange process. The tube sheets serve to hold the tubes in place in a tube bundle, and also can serve as baffles to create turbulence and a more constant residence time for the shell side fluid. The end channels distribute the tube side fluid and create either a transition to the outlet nozzle or a method to send the tube side fluid back to the other end of the heat exchanger. Many shell and tube heat exchangers are the work horse of industry.

There are two models of variances that are typically employed in this types of application, namely U-tube and straight tube variances. Usually, tube sheets are in place to secure the position of the tubes and to baffle the flow of shell fluid. When a U-tube design is used, the fluid enters and exits the exchanger at the same end.

The other type of design is the straight tube exchanger. For fluids that tend to foul the tubes, a straight tube heat exchanger is used, due to its relative ease of cleaning. If fluids have far different thermal expansion properties it is best to use a U-tube exchanger because it will allow the shell and the tubes to expand independently.

In reference to the tube side fluid, the number of passes refers to the number of times the tube side fluid is redirected within the system prior to leaving via the exit nozzle. The shell and tube heat exchanger is commonly made in single pass, two pass and four pass configurations, although custom multi-pass heat exchangers with yet another number of passes are also available. The U-tube exchanger has an inherent two pass system in place. For a straight tube, two pass heat exchanger, instead of a U-tube bundle, the end channel and an internal horizontal baffle, are utilized to cause the two passes.

The choice of configuration for a shell and tube heat exchanger affects the overall heat transfer coefficient and thus affects the heat exchanger tube surface area required. Frequently the fluid flows within the system are a mixture of counter flow, cross flow and parallel flow. In general counter flow is the most effective configuration for lessening the required heat transfer surface area