Since the 1920s, the plate heat exchanger used in food industry has been developed into various forms due to its compact structure and good heat transfer effect. Now heat exchanger is widely used as heat transfer equipment, and it is widely used in industry, especially in the field of large energy consumption. With the rapid development of energy-saving technology, there are more and more types of heat exchanger, which are suitable for different media, different working conditions, different temperatures and different pressures. The structure and type of heat exchanger are also different The development of high-efficiency heat exchanger is constantly updated, and the specific classification is as follows: 1. According to the different heat transfer methods, the main working principle of hybrid heat exchanger is that two kinds of medium transfer heat each other through contact, so as to realize heat transfer. The contact area directly affects the heat transfer, and the medium of this kind of heat exchanger is usually gas, The other is liquid, which is mainly heat transfer equipment with cooling tower equipment as the main body, but it usually involves mass transfer, so it is difficult to distinguish the relationship with the tower. It is usually classified as tower equipment, and the cooling tower used in chemical plant and power plant is the most typical hybrid heat exchanger. 2. The principle of this kind of heat exchanger is that the hot medium first reaches a certain temperature by heating the solid material, then the cold medium is heated by the solid material, and the cold and hot alternate to achieve the purpose of heat transfer. It is mainly used to recover and utilize the heat of high temperature waste gas. 3. The principle of this kind of heat exchanger is that the cold and hot media are separated by the solid partition, and heat exchange is carried out through the partition. The consumption of this kind of heat exchanger is very large, accounting for 99% of the total. According to the different structure, it can be divided into tube type, plate type and other types. 2、 No phase change heat transfer: generally divided into heater and cooler. 2. Phase change heat transfer: generally divided into condenser and reboiler. Reboiler is divided into kettle reboiler, siphon reboiler, reboiler, evaporator, steam generator and waste heat boiler. 3、 According to the different classification of heat transfer elements, 1. Tubular heat transfer elements include floating head heat exchanger, fixed tube sheet heat exchanger, stuffing box heat exchanger, U-tube heat exchanger, snake tube heat exchanger, double shell side heat exchanger, single tube heat exchanger, multi tube heat exchanger, external draft tube heat exchanger, baffle rod heat exchanger, heat pipe heat exchanger, intubation heat exchanger 2. Plate heat transfer elements include spiral plate heat exchanger, plate heat exchanger, plate fin heat exchanger, plate shell heat exchanger, plate evaporator, plate condenser, printed circuit board heat exchanger, etc. 4 According to the classification of air-cooled heat exchanger, there are dry air cooler, wet air cooler, dry wet combined air cooler, power station air cooler, surface evaporative air cooler, plate air cooler, energy recovery air cooler, natural convection air cooler, high-pressure air cooler, perforated plate heat exchanger, etc Corrugated tube heat exchanger, special-shaped tube heat exchanger, surface porous tube heat exchanger, spiral flat tube heat exchanger, spiral grooved tube sheet heat exchanger, ring grooved tube heat exchanger, longitudinal grooved tube heat exchanger, spiral wound tube heat exchanger, T-shaped finned tube heat exchanger, new structure high efficiency heat exchanger, insert heat exchanger, serrated tube heat exchanger, etc.