one medium flows through the shell chamber and the second medium through the tube chamber. The flow through the shell chamber is controlled by baffles, allowing as much cross flow to the tubes as possible. The form and spacing of the baffles is adapted to the application.Depending on the expediency, speed and pressure loss, the flow through the tube chamber is carried out by a single pass or multiple passes. With the exception of radiation losses, the input heat quantity is the same as the output heat quantity.

The heat transfer performance of a heat exchanger is the product of the mean logarithmic temperature difference, the heat transfer surface and the heat transfer coefficient. The latter is largely determined by the flow characteristic of the media, i.e. by the design features.