What are the categories of heat exchange equipment based on their principle? What are their respective features?

Classification: partition type, regenerative type, mixed type.

Heat exchangers can be classified into three types based on the heat transfer method: mixed-type, regenerative-type, and shell-and-tube-type. A mixed-flow heat exchanger is a type of heat exchanger that facilitates heat exchange through the direct contact and mixing of cold and hot fluids, and is also known as a contact heat exchanger. Since the two fluids must be separated promptly after mixed heat exchange, this type of heat exchanger is suitable for heat exchange between gas and liquid fluids. A regenerative heat exchanger is a type of heat exchanger that utilizes alternating flow of cold and hot fluids over the surface of the regenerative material (filling) in the regeneration chamber to facilitate heat exchange. In a partitioned heat exchanger, the cold and hot fluids are separated by a solid partition, and heat exchange takes place through this partition; hence it is also known as a surface-type heat exchanger. This type of heat exchanger is the most widely used. Interwall heat exchangers can be classified into tubular, plate-type, and other types depending on the structure of their heat transfer surfaces. Tubular heat exchangers use the surface of the tubes as the heat transfer surface, including coiled tube heat exchangers, shell and tube heat exchangers, etc ； Plate-type heat exchangers use plates as the heat transfer surfaces, and include plate heat exchangers, spiral plate heat exchangers, plate-fin heat exchangers, shell-and-plate heat exchangers, and umbrella plate heat exchangers, among others.

Based on the heat transfer principles, heat exchangers are classified into three types: direct contact heat exchangers, storage-type heat exchangers, and plate-and-tube heat exchangers

Based on the method of heat transfer, heat exchangers can be divided into three categories: mixed-type, regenerative-type, and shell-and-tube type. A mixed-type heat exchanger is one in which heat exchange occurs through the direct contact and mixing of cold and hot fluids; it is also known as a contact-type heat exchanger. Since the two fluids must be separated promptly after mixed heat exchange, this type of heat exchanger is suitable for heat exchange between gas and liquid fluids. For example, in the cooling towers used in chemical plants and power plants, hot water is sprayed from above downward, while cold air is drawn in from below. On the surface of the water film in the filler, as well as on the surface of droplets and mist, hot water and cold air come into contact with each other to exchange heat; the hot water is cooled and the cold air is heated, after which they are separated promptly due to the difference in density between the two fluids. A regenerative heat exchanger is a type of heat exchanger that utilizes the alternating flow of cold and hot fluids over the surface of the regenerator (filling material) located within the regeneration chamber, thereby enabling heat exchange; an example of such a device is the regeneration chamber used to preheat air beneath a coke oven. These types of heat exchangers are mainly used to recover and utilize the heat from high-temperature waste gases. Devices of a similar type designed to recover cold energy are called heat exchangers, and they are commonly used in air separation units. In a partitioned heat exchanger, the cold and hot fluids are separated by a solid partition, and heat exchange takes place through this partition; hence it is also known as a surface-type heat exchanger. This type of heat exchanger is the most widely used. Interwall heat exchangers can be classified into tubular, plate-type, and other types depending on the structure of their heat transfer surfaces. Tubular heat exchangers use the surface of the tubes as the heat transfer surface, including coiled tube heat exchangers, shell and tube heat exchangers, etc ； Plate-type heat exchangers use plates as the heat transfer surface, including plate heat exchangers, spiral plate heat exchangers, plate-fin heat exchangers, shell-and-plate heat exchangers, and umbrella plate heat exchangers, among others ； Other types of heat exchangers are designed to meet certain special requirements, such as scraped surface heat exchangers, rotary disk heat exchangers, and air coolers.