A heat exchanger for heating is a technical device that transfers heat between hot and cold environments. Devices of this type used for heating systems are divided into several categories depending on the principle of operation, the interaction of media, the method of heat transfer, as well as the direction of movement of the carrier and the heat consumer. When choosing a heat exchanger for a house or a bath, the features of a particular heating system, the pros and cons of the device, its design and additional functionality are taken into account.
The device and principle of operation of the heat exchanger
The design of the heat exchanger directly depends on its type. Modern heating devices consist of two pressure plates with holes to which additional pipeline elements are connected. The carrier and consumer of heat also enter the interior of the device due to the presence of holes. The principle of operation of a heat exchanger is quite simple, it can be considered using the example of a plate unit. The heat flow in such a device affects the corrugated layer in it, which gradually picks up speed during operation.
After starting the first stage, the media begin to move towards each other on both sides to avoid mixing. Working channels are formed on the plates located in parallel; during movement along them, heat exchange takes place in each medium, as a result of which heat leaves the unit. In home or bathing plate units, internal flows can go according to a one-way or multi-way type, taking into account technical characteristics and specific conditions.
Before choosing a device, it is useful to read information about what a heat exchanger is for, learn about the types of the unit, the rules for its installation and operation.
Types by the principle of work
According to the way of interaction of media, heat exchangers can be surface and mixing. The connection diagram for the mixing heat exchanger is considered more complex.
Mixing
The operation of mixing units is based on the contact of two substances and mixing of the consumer and the heat carrier. Mixed heat exchanger for heating is divided into several categories, this includes chimney cooling towers, steam bubblers, as well as barometric condensers and nozzle heaters.
Surface
A surface heat exchanger works in a boiler room by transferring heat through the contact surface. These can be plates or pipes, depending on the type of device. The media inside such units do not mix with each other, which is their main difference from mixing analogs.
According to the principle of heat transfer, surface heat exchangers are divided into two types: regenerative and recuperative.
- The principle of operation of the recuperative heat exchanger is based on the continuous transfer of heat through the contact surface. This is how many plate-type devices work.
- The standard or secondary regenerative unit is designed to cool and heat the air. In these devices, the movement of the carrier and the heat consumer occurs in a periodic mode. Such installations are often used in multi-storey office buildings.
Recuperative appliances are divided into two categories depending on the surface. It can be made of pipes, this option is designed to work in conditions of high pressure drops. Devices with a sheet surface are more compact and lightweight, so the installation of this type of heat exchanger is almost no problem.
Shell and tube
The shell-and-tube device is made of finned tubes that increase the surface area that transfers heat. It can have a structure that includes tube sheets, with a rigid coupling of all parts and elements. Lattices in such a device are welded to the walls of the body, pipes are attached to it on the coupling. The floating head design is considered to be more advanced, devices of this type are more expensive, but are considered more practical.
Submersible
Devices of this type are often installed in high-rise buildings. They have a cylinder-shaped coil placed in a vessel with liquid. Due to the simple design, the time for heat release is noticeably reduced.
Spiral
The piping of such a heat exchanger consists of metal sheets twisted into a spiral and fixed on a roll. Aggregates of this type require good sealing. You also need to take into account that the installation of a spiral heat exchanger requires special skills. Spiral devices are not used in systems with a pressure of more than 10 kgf / cm2.
Lamellar
Plate devices are deservedly considered the most advanced and are ideal for both private houses and industrial premises. They do not cause problems during assembly and cleaning, and have a minimum degree of resistance to hydraulics. The scheme for supplying the working medium to them can be carried out in three ways: direct-flow, mixed and counter-flow.
Advantages and disadvantages
Modern units are easy to maintain and do not cause problems during disassembly and flushing of the device. Plate heat exchangers, which are most often installed, foul more slowly due to increased turbulence and high-quality polishing.
Heating units from leading manufacturers last longer than hot water boilers, hot water boilers and stoves for houses and garages. The average service life of the unit is about 10-20 years. Most devices have virtually no flaws except for the need to clean the device as it gets dirty. To reduce the accumulation of dirt inside the device, you should always use a good quality heat transfer fluid.
Selection rules
The list of the main criteria that you need to pay attention to when choosing includes:
- the type and quality of the heat carrier used;
- ease of disassembly and assembly;
- type of heat transfer;
- the ability to increase the amount of power during operation.
Plate exchangers are more often used for cooling and heating systems for refrigerators and swimming pools, spiral exchangers are used in various industries, horizontal exchangers are better suited as heating devices.
Operation and care
Timely inspection, prevention and replacement of parts will help save on repairs and buying a new device. The operation of the unit is adversely affected by the processes of corrosion and erosion of parts, frictional wear during increased vibration, as well as exposure to high temperatures.
If problems are not corrected in time, the structure may fail. You can clean the device yourself or entrust it to a specialist.
Popular manufacturers
Collapsible and brazed heat exchangers from the RIDAN and ASTERA brands, which are distinguished by a high level of quality and the availability of necessary spare parts, have proven themselves in the Russian market.
From foreign brands, buyers often choose diesel and standard devices from ALFA LAVAL, DANFOSS and SONDEX.
When choosing a unit, it is necessary to take into account the features of the system as a whole, the estimate, if it is a project, the requirements for the number of kW, as well as other necessary parameters.
