Heat Exchanger

A heat exchanger is a device which is used for making any fluid(like water/ vapour etc) cooler and at the same time, it can make the other fluid/fluids hotter.
Actually, it exchanges heat but doesn't mix up the fluids.The properties of different fluids are same after leaving the heat exchanger for that reason its one of the best inventions

Working procedure :

These are some examples.Actually, all the flow paths are separated from each other, for that the fluids don't mix.

Examples:

There are many kinds of heat exchangers. But some examples are given:
space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air.