Three classifications of heat

According to different heat transfer modes, heat exchangers can be divided into mixed type, regenerative type and partition type.

Hybrid heat exchanger is a heat exchanger that exchanges heat through direct contact and mixing of cold and hot fluids, also known as contact heat exchanger. Since the two fluids must be separated in time after mixing and heat exchange, this kind of heat exchanger is suitable for heat exchange between gas and liquid. For example, in the cooling towers used in chemical plants and power plants, hot water is sprayed from top to bottom, while cold air is sucked from bottom to top. On the surface of the water film or the surface of droplets and water droplets of the filler, hot water and cold air contact each other for heat exchange. The hot water is cooled and the cold air is heated, and then the two fluids are separated in time depending on the density difference between them.

The cold and hot fluid of the wall heat exchanger is separated by the solid wall, and the heat exchanger exchanges heat through the wall, so it is also called the surface heat exchanger, which is the most widely used. Regenerative heat exchanger is a heat exchanger that uses cold and hot fluids to alternately flow through the surface of the regenerator (filler) in the regenerator to exchange heat, such as the regenerator under the coke oven to preheat air. This kind of heat exchanger is mainly used to recover and utilize the heat of high-temperature exhaust gas.

According to the structure of heat transfer surface, the wall heat exchanger can be divided into tube type, plate type and other types. The tube heat exchanger takes the tube surface as the heat transfer surface, including snake tube heat exchanger, casing heat exchanger and shell and tube heat exchanger; The plate surface heat exchanger takes the plate surface as the heat transfer surface, including plate heat exchanger, spiral plate heat exchanger, plate fin heat exchanger, plate shell heat exchanger and umbrella plate heat exchanger; Other types of heat exchangers are designed to meet some special requirements, such as scraped surface heat exchangers, rotary table heat exchangers and air coolers.