HEAT EXCHANGERS

 Types Of Heat Exchangers

A heat exchanger is a device designed to efficiently transfer or “exchange” heat from one matter to another (between a solid object and a fluid, or between two or more fluids). When a fluid is used to transfer heat, the fluid could be a liquid, such as water or oil, or could be moving air. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact.

Their applications includes:

1. Space heating
2. Refrigeration
3. Air conditioning
4. Power stations
5. Chemical plants
6. Petroleum refineries
7. Natural-gas processing
8. Sewage treatment

The classic example of a heat exchanger is found in an IC (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. Another example is the heat sink , which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant.

Heat is transferred by conduction through the exchanger materials which separate the mediums being used. A shell and tube heat exchanger passes fluids through and over tubes, whereas an air-cooled heat exchanger passes cool air through a core of fins to cool a liquid.

There are various types of heat exchangers-

1. Shell and tube heat exchanger
2. Plate heat exchangers
3. Plate and shell heat exchanger
4. Adiabatic wheel heat exchanger
5. Plate fin heat exchanger
6. Pillow plate heat exchanger
7. Fluid heat exchangers
8. Waste heat recovery unitsDynamic scraped surface heat exchanger
9. Phase-change heat exchangers
10. Direct contact heat exchangers
11. Micro-channel heat exchangers

Heat exchangers are commonly used for cooling of hot gasses and liquids, especially in industrial and manufacturing processes. They can also be used to generate heat; for example, an Exhaust Gas Heat Exchanger can use the heat from exhaust gasses to heat up a water circuit, which can then be used around a building.