A tube heat exchanger is a special design type of a heat exchanger.
Wikipedia definition (similar term):
Concentric Tube (or Pipe) Heat Exchangers are used in a variety of industries for purposes such as material processing, food preparation, and air-conditioning. They create a temperature driving force by passing fluid streams of different temperatures parallel to each other, separated by a physical boundary in the form of a pipe. This induces forced convection, transferring heat to/from the product.