A heat exchanger is a machine built for competent heat transfer from one medium to another. The media may be divided by a solid wall, so that they never mix, or they may be in straight contact. They are generally used in space heating, refrigeration, air conditioning, power plants, chemical plants, petrochemical plants, petroleum refineries, natural gas processing, and sewage treatment. One general example of a heat exchanger is the radiator in a car, in which the heat source, being a hot engine-cooling fluid, water, transfers heat to air flowing through the radiator.
There are two main classifications of heat exchangers according to their stream planning. In parallel -flow heat exchangers, the two fluids come in the exchanger at the same end, and travel in parallel to one a different to the other side. In counter-flow heat exchangers the fluids go through the exchanger from reverse ends. The oppose present design is most efficient, in that it can move the most heat from the heat (transfer) medium.
Types of heat exchangers:-
- Shell and tube heat exchanger
- Plate heat exchanger
- Adiabatic wheel heat exchanger
- Plate fin heat exchanger
- Fluid heat exchanger
- Waste heat recovery units
- Dynamic scraped surface heat exchanger
- Phase-change heat exchangers
- Direct contact heat exchangers