List 3 types of heat exchangers, and classify them?

Concentric tubes or double tube.

Casing and tubes.

Plates.

Explanation:

There are two classify of heat exchange:

1) Direct contact heat exchanger: the exchange heat is produced by the mixture betweenn two fluids, for example refrigeration towers.

2) Indirect contact heat exchange: the fluids never mix, and exchange the heat across a surface.

For example:

Concentric tubes or double tube: the fluid travel trough the central tube, and in the extern tube (bigger diameter) have other fluir with a different tempreature which can give o became the heat of the central fluid.

Casing and tubes are used in Industries, which have a lot of tube inside tha casing.

Plates: the fluid travel throug the metal plates.