Definition and Classification of Heat Exchangers

In order to achieve efficient heat transfer, a heat exchanger is a device that separates media through solid walls for efficient heat transfer. These media may be separated by solid walls to ensure that they do not mix with each other, or they may be in direct contact. Heat exchangers are widely used in many fields, such as space heating, refrigeration, air conditioning, power plants, chemical plants, etc. Common types of heat exchangers are plate and shell and tube types. In addition, there are thermal storage heat exchangers, adiabatic wheel heat exchangers, plate-fin heat exchangers, fluid heat exchangers, waste heat recovery devices, and dynamic scraped surface heat exchangers. The classification of heat exchangers is usually based on the relative flow direction of the two fluids in the equipment. The three categories are parallel flow, counterflow, and crossflow.