How Industrial Heat Exchangers Work
Heat exchangers are essential components in many industrial processes, allowing for the efficient transfer of heat between two fluids or a fluid and a solid. Industrial heat exchangers are used in a wide range of applications, from power generation and HVAC systems to chemical processing and oil and gas production. In this article, we will discuss the different types of industrial heat exchangers and how they work to transfer heat.
Types of Industrial Heat Exchangers
There are several types of industrial heat exchangers, each with their own unique design and operating principles. The most common types include:
- Shell and tube heat exchangers: These heat exchangers consist of a tube bundle, enclosed in a cylindrical shell. One fluid flows through the tubes, while the other flows over the outside of the tubes, in the shell. This type of heat exchanger is often used in applications where one fluid is at a higher pressure than the other.
- Plate heat exchangers: These heat exchangers consist of a series of thin metal plates, stacked together to form a series of channels for the fluid to flow through. The fluids flow in opposite directions, and heat is transferred between the plates. Plate heat exchangers are often used in applications where the fluids are corrosive or have a high fouling tendency.
- Air-cooled heat exchangers: These heat exchangers use air to cool the fluid, rather than a separate coolant. They are often used in applications where water is scarce or where the fluid must be cooled quickly.
How Industrial Heat Exchangers Work
The basic principle behind industrial heat exchangers is the transfer of heat from one fluid to another. This is accomplished through a process called conduction, in which heat is transferred through a solid material, such as the metal walls of a heat exchanger.
In a shell and tube heat exchanger, one fluid flows through the tubes, while the other flows over the outside of the tubes, in the shell. As the hot fluid flows through the tubes, it transfers its heat to the cooler fluid flowing over the outside of the tubes.
In a plate heat exchanger, the fluids flow in opposite directions and the heat is transferred through the thin metal plates. As the hot fluid flows through one side of the plate, it transfers its heat to the cooler fluid flowing on the other side of the plate.
In an air-cooled heat exchanger, the fluid is cooled by passing through a series of fins or coils, through which air is blown. As the hot fluid flows through the fins or coils, it transfers its heat to the air, which cools the fluid.
Industrial heat exchangers are essential components in many industrial processes, allowing for the efficient transfer of heat between two fluids or a fluid and a solid. The three most common types of industrial heat exchangers are shell and tube heat exchangers, plate heat exchangers, and air-cooled heat exchangers. Each type of heat exchanger works on the basic principle of transferring heat from one fluid to another through conduction, and they are used in a wide range of applications in various industries.
What is a heat exchanger
Not all industries need a heat exchanger, but only those that have to carry out specific production processes, such as: pasteurization, sterilization, a change of state such as crystallization, evaporation or condensation, or cooling or heating of fluid currents. From this it can be deduced that these appliances are indispensable in the food or chemical and petrochemical industries, where the production environments must have a high level of safety. The most common industrial heat exchangers are those with plates, shell and tube or finned coils.
The choice varies from the type of production to be performed, the size of the industrial plant and the safety standards to be respected. A major distinction that must be made is between water/air exchangers and air/air exchangers, because they have differences in price, functioning and methods of use.
The water/air exchangers for industrial use are able to cool/heat an environment in a very short time. They are chosen in very large buildings instead of air conditioners because they offer great savings in terms of energy and money. Usually, industries choose these heat exchangers if the air inside the plants is oily or full of dust, since they prevent humidity from entering the electrical panel. A water/air exchanger can only be installed if the temperature outside the system is higher than the inside.
The air/air exchangers for industrial use are usually installed when the external temperature of the system is lower than the internal one. These appliances are perfect for systems or very small rooms, since they have a lower cooling capacity than water/air exchangers, however they also require less maintenance.
Different types of heat exchangers
On the market you can find different types of heat exchangers, made with different solutions based on your needs, which can be different based on the type of industry.
The simplest and most standard heat exchanger is the double tube one, which is made up of 2 concentric tubes of different diameters: the first fluid flows in the smaller diameter tube while the second fluid flows in the annular duct between the two tubes. The flows can be of two types: equi-current (when the fluids travel in the same direction) or counter-current (when the fluids travel in opposite directions).
The tube and shell heat exchanger is the most used model in industrial applications. This type of exchanger is characteristic for the large number of tubes that make it up (there can be even hundreds of tubes) and a cylindrical shell that contains them.
The plate heat exchanger is made up of metal plates with holes that allow the fluids to pass through small ducts. Its peculiarity lies in the sides of the plate, which come into contact with hot and cold fluids alternately.
The regenerative exchanger allows the alternating passage between the hot fluid and the cold fluid, as occurs in the plate exchanger. However, there is a difference between static and dynamic. The static regenerative heat exchanger has a large thermal capacity and a porous structure, characterized by a mesh of ceramic material wires. The dynamic regenerative exchanger, on the other hand, allows a continuous flow of hot and cold fluids and consists of a rotating drum, which comes into contact during rotation with both fluids alternately and works as a useful tool for storing thermal energy.
All these heat exchangers can be very efficient, but over time things can change due to an accumulation of materials of various kinds in the walls, which create resistance during the heat exchange process, thus reducing their efficiency. However, this may also not happen if adequate periodic maintenance is carried out, as the appliances must always be cleaned and checked by expert hands to be considered safe and efficient over the years.