What is a heat exchanger and how is it classified?

A heat exchanger, to put it simply, is a device that implements the process of heat transfer, where heat is always transferred from a high temperature to a low temperature. Its main functions are heating, cooling and waste heat recovery. The three modes of heat transfer are: conduction, convective transfer and radiation. Convection has been proven to be the most effective method of heat transfer.

The main function of the heat exchanger is to provide the required temperature to the media in each process to meet the smooth progress of production, but also recover waste heat, make full use of waste heat, low heat, improve the efficiency of resource utilization, save resources, energy saving and emission reduction.

According to the working principle, the heat exchanger can be divided into 3major categories, direct hybrid heat transfer, heat storage heat transfer, and inter-wall heat transfer.Of the three methods, interwalled heat transfer is the most widely used.

Direct mixingis the direct mixing of hot and cold media, such as a cool water tower. Heat storageis the exchange of heat between cold and hot fluids through the packing in turn, using the heat storage and exothermic of the packing. Heat transfer between walls, also known as surface heat transfer, where hot and cold fluids are separated by the wall surface without direct contact, heat and hot fluids can be exchanged by avoiding transfer to cold fluids.

The first two features are more obvious, is a simple structure, high heat transfer efficiency, good effect, but the disadvantage is that the hot and cold media must be mixed in order to use, so the scope of use is greatly reduced; between the wall heat exchanger has all the advantages of the first two, in addition to the wall to separate the hot and cold media, the scope of application becomes larger.

Heat exchangers are used in a wide range of applications, including petroleum, chemical, power, atomic, textile, beer, pharmaceutical, etc. They are common equipment in many industries.

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