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 process plants, 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.