What is the recovery process? Recovery in ventilation systems. Analysis of recovery systems and economic feasibility of their use. Features of recuperators with intermediate heat carrier

Ventilation systems in latest versions are no longer limited to a standard set of functions, the main of which is updating the air environment. For example, through the use of technological filters, the equipment minimizes the content of harmful particles in the room and also prevents the entry of odors. They are also improving in terms of microclimate regulation, which is especially beneficial from the point of view of energy saving. To ensure this possibility, supply and exhaust units with air flow recovery are used. The operation of such systems is based on the processing of heat flows that pass through the elements of the ventilation unit. As a result, the user receives not only fresh, but also heated naturally air.

What is the principle of recovery?

The recovery process occurs against the background of the interaction of air flows with different temperatures. That is, heated flows give up their heat to cold ones, thus forming an optimal temperature balance. Recovery is the transfer of heat to fresh air, which is carried out in a special heat exchanger. At the same time, there are different levels efficiency this process. For example, an open window shows zero efficiency. In this case, the supply air flows do not heat up, but lower the air temperature in the room itself. We can say that this is a process that is the opposite of recovery.

The average level of efficiency varies in the range of 30-90%. The optimal rate reaches 60%, and systems that demonstrate a rate above 80% are considered the most productive. The most effective recovery is a heat exchange process in which the heating of the supply air flows reaches a level corresponding to the removed air. But even modern technologies do not allow achieving 100 percent efficiency.

Recuperator in the ventilation system

The recovery principle is implemented in the ventilation system in the form of a surface heat exchanger. The process of heat distribution itself is carried out using a wall that separates two oppositely directed flows. Regenerators have a similar device, but the recovery system differs in that the channels for working with air remain the same throughout the entire period of operation. It must be said that climate control equipment can serve not only air environments. Likewise, recovery is also used when working with gas, liquids, etc. There are also different design schemes. The most common are ribbed, tubular and plate models. At the same time, different approaches to the design of flow channels are provided - for example, direct-flow, counter-flow and cross-flow devices can be distinguished.

Cross plate recuperator

In such installations, membrane partitions are usually used, which ensure effective recovery. A special feature of the system is that as air is removed, excess moisture also comes out. The supply and exhaust system with recovery is also resistant to freezing, which is achieved without special heaters. This advantage allows the use of equipment with a cross-membrane design in conditions temperature regime up to -35 °C.

Such installations are used both in residential buildings and in warehouses where large areas are supposed to be serviced. They have also become widespread in agriculture- for example, in the arrangement of poultry houses, vegetable stores and livestock farms. Since heat recovery in cross-membrane designs also allows for effective cooling in summer, this system is also in demand in the manufacturing industry.

Finned plate systems

The design of such a recuperator involves the presence of finned thin-walled plates made by high-frequency welding. Metal panels form a structure with alternating partitions rotated 90 degrees. Due to this scheme, a high temperature of the heating medium is achieved, a minimum level of resistance, as well as an optimal ratio of the area of the teletransmitting surface to the weight of the heat exchanger. In addition, air handling units with heat recovery with finned plates are durable and low in price. Practice confirms that such systems allow saving of about 40%, that is, heating costs are minimized, since fresh air is effectively warmed up by the removed flows.

Rotary models

The features of such installations include low cost and fairly high productivity. Although, in terms of fresh air heating performance, this option is inferior to the plate design with a double cassette. Despite the simple configuration of the working elements, the rotary recuperation unit suffers from non-ideal distribution of air flows. There is a certain risk that clean air will mix with the exhaust air and, as a result, the quality of ventilation as such will suffer. The disadvantages of such systems include the need for frequent maintenance, which is especially disadvantageous when used in residential premises. However, the heating process itself is quite effective.

Direct-counterflow systems

A special feature of this type of recuperator is its tubular design, the elements of which are represented by thin-walled welded elements. During the operation of an installation of this type, a wall vortex is formed, which increases heat transfer, but at the same time is destroyed as the resistance in the air channel increases. Most often, such systems are used in industry, where delicate heating of one of the working media is required. Also, direct-counterflow equipment is used in mechanical engineering for heat dissipation and recovery. A household air handling unit with recovery of this type is also in demand - it is recommended to install it in rooms with sealed metal-plastic windows, as well as in ecological houses.

Such recuperators, as a rule, are integrated into a single air duct casing, which during operation ensures low energy consumption, compact dimensions with the possibility of hidden installation, high performance and reliability of the equipment.

Recuperators for energy efficient houses

The very concept of ventilation systems, which provide passive heating of fresh air, is aimed at reducing heating bills. But in terms of equipment, recuperation is also an environmentally friendly way to normalize the microclimate. Manufacturers produce special lines that use materials that are safe and efficient in terms of recovery. In particular, latest models three-stage heat exchangers made of non-porous ultrathin membranes are obtained. This device eliminates the need for electric air heaters.

In addition to uniform heat transfer, such devices also work effectively with humidity. They provide complete return of moisture to the room with the complete exclusion of condensers. As a result, ventilation with recovery eliminates the need to install drainage systems.

Automation for recuperators

Supply and exhaust systems are developing in the direction electronic filling. In order to optimally distribute flows, manufacturers equip installations with the ability to automatically adjust the position of interchannel partitions. More advanced models also provide for setting speed modes, indicating temperature indicators and monitoring the degree of filter contamination with an alarm. Besides, modern ventilation with recovery provides the ability to control an external duct heater without connecting third-party devices to the process. That is, in this case, additional heating of the air is provided to the optimal level.

Filters in recuperators

Like all modern ventilation systems, models with recovery require the inclusion of cleaning devices in the design. Since heat exchange involves the maximum reduction of outgoing and injected air flows, filters play a particularly important role in this case. important role. Most often, F7 type filters are used in the air ducts themselves, which exclude the passage of particles 0.5 microns in size. G3 is less common, but depending on the design, such an addition may be required. For ease of maintenance, the recovery system is often equipped with filters made of plastics and special fibers - such elements are easy to wash and shake out. As already noted, modern models They are also equipped with indicators that determine the moment to replace the filter.

Advantages of recuperators

Technologies used in supply and exhaust systems recovery, minimize energy consumption and increase the ergonomics of climate control equipment. In practice, the user of such an installation can also feel an improvement in microclimate indicators. Of course, heat recovery is not as effective from the point of view of the heating function as special heating units, but its operation does not require additional energy consumption. Inclusion in systems aids heating allows you to balance both the increase in temperature and savings in energy costs. In general, according to expert calculations, the use of recuperation allows reducing heating costs by 10-15%.

Disadvantages of recuperators

Such systems have two serious drawbacks. First of all, this is icing of heat exchangers in winter. For this reason, many users complain about equipment failure already in the first weeks of operation in frosty conditions. However, manufacturers are striving to improve the protective qualities of equipment by providing installations with durable fans. The second disadvantage that air handling units with recovery have is their noisy operation. This is especially evident in rotary models. At the same time, developers strive to provide new models with improved insulation means, so low-noise options can also be found on the market.

What to consider when choosing an installation with a recuperator?

A consumer who decides to install such a system in his home should focus on system performance, design and functionality. Thus, the performance indicator determines the ability of ventilation to operate in a room of a specific area. The design in which the equipment is made is no less important. For example, a heat recovery unit with tubular elements allows convenient installation with minimum requirements to a free place. As for functionality, it affects both the ability to regulate the microclimate in the room and the ergonomic characteristics of the system.

Conclusion

The operation of traditional ventilation systems does not give even a hint of an energy-saving function. As a rule, these are power-hungry, massive installations that make a significant contribution to increasing home maintenance costs. Against this background, recovery is an almost revolutionary approach to the production of climate control equipment, which involves the rational use of already waste thermal energy. If in standard system Since air is heated as it enters the room using heating equipment, recuperation allows one to initially increase the temperature of incoming flows without connecting special heaters. Of course, such installations have their drawbacks, but manufacturers are fighting a fruitful fight against them, improving the designs of recuperators.

When operating ventilation units in residential buildings or production premises In order to save money, it is necessary to provide for the installation of energy-saving equipment, called supply and exhaust ventilation systems using thermal energy recovery processes, even at the design stages.

The device itself, called a “recuperator,” is a certain type of heat exchanger consisting of double walls that allow both cold supply and exhaust to pass through. warm air. The main characteristics of recuperators include their efficiency, which in most cases depends on some important parameters:

metal composition of the heat exchanger structure;
total area of contact with air flows;
ratio of the volume of air masses passed through (supply to exhaust).

In general, the differences between ventilation heat exchangers are also determined by many other factors that are included in specific types of recuperators.

Type classification of recuperators

Air recuperators are quite often equipped not only with a heat exchanger, but also with two fans for separate removal of clean and exhaust air. In addition, these devices may include various technical devices in order to improve the quality of the supplied air. Based on this, heat exchangers are classified according to the coolant used, design or flow pattern of coolants into the following types:

Plate recuperator (also called cross-point) is the most popular type of heat exchanger due to its compact design simplicity, relatively low cost and reliability. This type of equipment consists of a set of cassettes separated by supply and exhaust air flow channels made of galvanized metal. The efficiency of these devices can reach an average of 70%. and don't need to be used electrical energy. The main advantages of such ventilation units include:

increased efficiency (productivity level);
lack of electrical energy consumers;
convenient and simple installation;
quiet operation.

Their main disadvantage is the possible freezing of the heat exchanger as a result of the formation of excess condensate on the plates. To eliminate this drawback as much as possible, a household recuperator is equipped with outlets for collecting condensate liquid (condensate collectors). The only exception is cellulose heat exchangers.

A plate recuperator, the principle of operation of which is quite convenient and simple, and is based on the intersection without mixing in the heat exchanger of two flows of air masses (supply and exhaust) has sufficient efficiency due to the efficiency indicator, measured in percentage, and can correspond to the following values:

45-78% - when using plastic or metal heat exchangers;
60-92% - when using plate recuperators with a cellulose hygroscopic heat exchanger.

The duct plate recuperator can be used in premises where high requirements and standards are imposed on the cleanliness of the incoming air. To install a ventilation system, you can either purchase a ready-made device or make one.

Based on plate supply and exhaust units, there is also a membrane recuperator that allows simultaneous moisture and heat exchange in order to eliminate the need to create an additional drainage system to remove excess condensate. Membrane plates have selective permeability, which allows water molecules to pass through and gas molecules to be retained.

A rotary recuperator, the operating principle of which is based on the rotation of a rotary heat exchanger at a certain and constant speed, is a cylindrical structure, inside of which layers of corrugated metal are densely located. The built-in drum, performing rotational movements, initially passes heated air, after which the cold air is supplied. As a result, the corrugated layers are progressively cooled or heated and part of the heat is transferred to the cold air flow. Similar ventilation units have a number of advantages, among which are:
- partial return of moisture (no need for);
- the ability to regulate the speed of rotation of the rotors;
- compact design and installation.
Along with their advantages, rotary heat exchangers have significant disadvantages - they require the use of electricity, the installation of additional filtering components and have moving elements.

The efficiency of a rotary recuperator can be 60-85%, so they are used in systems characterized by high air flow rates.
A glycol recuperator is one of the representatives of installations with intermediate coolants, which allows you to connect two separate ventilation systems. This equipment is ideal for upgrading existing ventilation systems that operate separately from each other. A glycol recuperator, the operating principle of which is based on the installation of a heating heat exchanger with antifreeze supplied to it (circulation of a water-glycol solution), is often calculated individually. The basic characteristics of such installations include:
- the ability to adjust the system using built-in automation and coolant circulation speed;
- operation of the installation at sub-zero temperatures without the need for defrosting;
- connecting several inflows and one exhaust or vice versa;
- no moving parts;
- the gap between exhaust and inflow can reach up to 800m.
The main disadvantage is low efficiency - 45-60%.
Water recuperator is a type of air recuperator used in supply and exhaust systems. The mechanism of action of such a device is due to the transfer of heat through water. In this case, heat exchangers can be located at a remote distance using thermally insulated pipelines. This circumstance is the main purpose of the application - connecting ventilation lines. Water recuperators are used quite rarely due to low efficiency values and the need for frequent maintenance.

Main criteria for choosing recuperators

When selecting a suitable and optimally efficient recuperator, you must adhere to the following criteria:

level of recovery (energy saving) - depending on the manufacturer and model, this parameter should be in the range of 40-85%;
sanitary and hygienic indicators - the ability to control the degree of purification and quality of incoming air;
energy efficiency – the value of energy consumption;
operational characteristics - overall service life, suitability of equipment for performance repair work, the need for minimal maintenance;
adequate cost.

Taking into account all these indicators, choosing the highest quality and most efficient types of recuperators in terms of performance will not be very difficult for those who want to both create and improve the existing ventilation system.

Rename the topic. Doesn't look like an educational program at all. He's only interested in PR.
Now I'll correct it a little.
Advantages of a rotary recuperator:
1. High heat transfer efficiency
Yes, I agree. The highest efficiency among household ventilation systems.
2. Dehumidifies the air in the room, as it is not hygroscopic.
No one specifically uses a rotor for drying. Why is this included as a plus?
Minuses:
1. Large sizes.
I don't agree.
2. The rotor is a complex moving mechanism that is subject to wear, and operating costs will increase accordingly.
A small stepper motor that rotates the rotor costs 3 kopecks and rarely fails. You call it a “complex moving mechanism” that increases operating costs?
3. Air flows are in contact, due to which the admixture is up to 20%, according to some reports up to 30%.
Who said 30? Where did you get it? Please provide us with the link. I can still believe in 10 percent of the flow, but 30 is nonsense. Some plate recuperators are far from being hermetically sealed in this regard, and a small flow is normal there.
4. Condensate drainage is required
Dear educational programmer, read at least one instruction manual for the rotary installation for apartments and cottages. It is written there in black and white: at standard air humidity, condensate removal is not required.
5. Fastening the PVU in one position.
Why is this a minus?
6. Dehumidifies the air in the room, as it is not hygroscopic.
If you know the ventilation system market, you have already paid attention to the development of rotors made of hygroscopic material. The question of how much this is necessary and how much all this hygroscopicity is needed, including in plate-type recuperators, is a rather controversial question and often not in favor of hygroscopicity.
Thanks for the answer.
No one pretended to be an educational program. A topic for discussion and possible help for the user, as well as for me, as a user.
“Since I am a slightly interested person, I will compare it with what I work with.” - I wrote at the very beginning. I compare it with what I'm working with.
The rotary type has larger dimensions than the plate type. Because I compare it with what I work with.
The fact that it has the highest efficiency indicators is, in my opinion, not true; the triple plate type has more efficiency and higher frost resistance. Again, I compare it with what I’m working with.
This is a moving mechanism and is subject to wear, so it costs three kopecks. This is good.
Mounting in one position is a minus. It is not always possible to install exactly as shown in the diagram.
Hygroscopy is needed to reduce operating temperature, at which the recuperator will not freeze.

A special type of forced ventilation system is supply ventilation with heating and heat recirculation, which provides partial heating of the input air flow due to the warm air removed from the room using a special device - a recuperator. In this case, the main heating of the outside air is carried out by a conventional air heater.

Heat recovery in supply and exhaust ventilation – this is not a new phenomenon, but it is still not widespread in our country. From a technical point of view, recovery is the most common heat exchange process. The word “recovery” itself is of Latin origin and means “return of what was spent.” Ventilation recuperators heat returns part of it back to the room through heat exchange between the incoming and outgoing flow. The reverse process occurs in hot weather, when the outgoing cold air conditioning cools the oncoming warm air flow. In this case, it should be called cold recovery.

Why is recovery needed? Obviously, to save energy resources in the first place. A recuperator is a device in which heat exchanges between incoming and outgoing air masses. At normal ventilation, the temperature difference between incoming and outgoing air in the cold and hot seasons is significant. If, for example, it is -20°C outside and +24°C indoors, then the difference is more than 40°C. This difference will need to be covered by the heating system. In summer the difference is smaller, but it will also add load to the air conditioner. The recuperator allows you to reduce this difference to a minimum. Properly selected equipment ensures that at 0°C outside air and +20°C indoors, the difference between the incoming and outgoing flow is within 4°C, i.e. reduce it by five times. Recuperation efficiency drops as values decrease outside temperature, but, nevertheless, the savings remain very noticeable. Moreover, when there is a significant difference between indoor and outdoor temperatures, recuperation is especially useful.

Many modern construction technologies require airtight and vapor-tight enclosing structures. For effective ventilation and removal of water vapor from rooms with sealed walls and double-glazed windows, forced supply and exhaust ventilation is required. Heat recovery in this case is the key to comfortable air exchange with minimal heat loss.

In the USA and Canada, long before the advent of recovery equipment, in order to ensure that the air in the room was not too cold in winter and too warm in summer, they came up with the use of a ground heat exchanger, which was later called the “Canadian well”. His idea

is that the outside air, before entering the premises, passes through supply air ducts buried in the ground, acquiring a temperature value close to +10°C - constant temperature soil at a depth of 2 m or more. The Canadian well, in fact, is not a recuperator, but it reduces energy costs for heating and air conditioning. Ventilation of premises in traditional scheme with a Canadian well it is natural, but it can also be forced.

Recuperators as an element of ventilation equipment are actively used in European countries. The reason for their popularity is the economic benefits that heat recovery provides. There are two types of recuperators: plate and rotary. Rotary ones are more efficient, but also expensive. They are capable of returning 70-90% of heat. Plate ones are cheaper, but save less, in the range of 50-80%.

One of the factors influencing the efficiency of recovery is the type of room. If the temperature in it is maintained above 23°C, then the recuperator definitely pays for itself. And the more expensive the cost of energy, the shorter the payback period. The service life of recuperators is quite long, and with timely maintenance and replacement of inexpensive consumables, it is theoretically unlimited. Recuperators can be supplied as a monoblock or several separate modules.

The recuperator is a special type of heat exchanger to which the inputs and outputs of the supply and exhaust ducts of the ventilation system are connected. The polluted air removed from the room, passing through the recuperator, gives up its heat to the incoming outside air without directly mixing with it. This additional heating supply ventilation allows you to significantly reduce energy costs for heating the input air, especially in winter.

Plate recuperators

Plate recuperators are designed in such a way that the air flows in them do not mix, but contact each other through the walls of the heat exchange cassette. This cassette consists of many plates that separate cold air flows from warm ones. Most often, the plates are made of aluminum foil, which has excellent thermal conductivity properties. The plates can also be made of special plastic. These are more expensive than aluminum ones, but increase the efficiency of the equipment.

Plate heat exchangers have a significant drawback: as a result of the temperature difference, condensation forms on cold surfaces, which turns into ice. An ice-covered recuperator stops working effectively. To defrost it, the incoming flow is automatically bypassed by the heat exchanger and heated by a heater. Meanwhile, the escaping warm air melts the ice on the plates. In this mode, of course, there is no energy saving, and the defrosting period can take from 5 to 25 minutes per hour. To heat the incoming air during the defrosting phase, air heaters with a power of 1-5 kW are used.

Some plate heat exchangers use preheating of the incoming air to a temperature that prevents the formation of ice. This reduces the efficiency of the recuperator by approximately 20%.

Another solution to the icing problem is hygroscopic cellulose cassettes. This material absorbs moisture from the exhaust air flow and transfers it to the incoming air, thereby returning moisture back. Such recuperators are justified only in buildings where there is no problem of air humidification. The undoubted advantage of hygrocellulose recuperators is that they do not require electrical heating of the air, which means they are more economical. Recuperators with double plate heat exchangers have an efficiency of up to 90%. Ice does not form in them due to heat transfer through the intermediate zone.

Famous manufacturers plate recuperators:

SCHRAG (Germany),
MITSUBISHI (Japan),
ELECTROLUX,
SYSTEMAIR (Sweden),
SHUFT (Denmark),
REMAK, 2W (Czech Republic),
MIDEA (China).

Rotary recuperators

Unlike lamellar ones, partial mixing of incoming and outgoing air occurs in them. Their main element is a rotor mounted in the body, which is a cylinder filled with layers profiled metal (aluminum, steel). Heat transfer occurs during the rotation of the rotor, the blades of which are heated by the outgoing flow and transfer heat to the incoming flow, moving in a circle. The efficiency of heat transfer depends on the rotor speed, and it is adjustable.

In a rotary recuperator, it is technically impossible to completely eliminate the mixing of incoming and outgoing air. In addition, this type of equipment requires more frequent and more extensive maintenance due to the presence of moving parts. Nevertheless, rotary models are quite popular due to their high heat recovery rates (up to 90%).

Manufacturers of rotary recuperators:

DAIKIN (Japan),
KLINGENBURG (Germany),
SHUFT (Denmark),
SYSTEMAIR (Sweden),
REMAK (Czech Republic),
GENERAL CLIMATE (Russia-UK).

From an economic point of view, heat recuperators will definitely pay off sooner or later, but much depends on how efficiently the recuperation itself is organized. The equipment is highly reliable, and the consumer can count on a long period of operation. Many companies produce a wide range of air exchangers designed specifically for apartments. Thus, an air handling unit with heat recovery for a 2-3-room apartment can cost about 17,000 rubles. The performance of the ventilation system in apartments is in the range of 100-800 m³/h. For country cottages this figure is about 1000-2000 m³/h.

Recuperators with intermediate coolant

This heat exchanger consists of two parts. One part is in the exhaust duct, the other in the supply duct. Water or a water-glycol solution circulates between them. The removed air heats the coolant, which, in turn, transfers heat to the supply air. In this recuperator there is no risk of transfer of contaminants from the exhaust air to the supply air. Changing the circulation rate of the coolant can regulate heat transfer. These recuperators have no moving parts, but they have low efficiency (45-60%). Mainly used for industrial facilities.

Chamber recuperators

The shutter divides the chamber into two parts by a shutter. One part is heated by the exhaust air, then the damper changes the direction of the air flow. Thereby, supply air heats up from the warm walls of the chamber. Contamination and odors can be transferred from the exhaust air to the supply air. The damper is the only moving part of this heat exchanger. Its efficiency is quite high (70-80%).

Heat pipes

This recuperator consists of a sealed tube system. They're filled freon or other easily evaporating component. These substances evaporate when heated by the removed air. The vapor condenses in another part of the tube and again turns into a liquid state. In this heat exchanger, the transfer of contaminants is excluded, there are no moving parts, and the efficiency is quite low (50-70%).

Many believe that RECOVERY RECOVERERS are expensive, bulky, difficult to integrate into technological processes devices with a short service life, and their repair stops production for a long period, making the use of a recuperator ineffective. The listed disadvantages allow skeptics to put up with colossal losses of thermal energy and environmental problems. As a result, recuperators are not installed at all enterprises where this is advisable.

The solution may be the installation of Finned Plate Heat Exchangers (OPT™ type recuperators)

Technical features of OPT type recuperators

due to the return of thermal energy, reduce the cost of its purchase by up to 40%;
reduce fuel consumption by increasing the combustion temperature of exhaust gases (heating scheme for boiler rooms, furnaces, etc.);
improve quality characteristics fuel combustion through the use of previously heated air, reduce mechanical underburning of fuel in the furnace heating cycle in boiler houses and other facilities;
cool flue gases to comply with environmental requirements and sanitary standards;
use the heat of exhaust gases for space heating, warming up the street air;
for technological processes requiring low temperatures, cool the exhaust flue gases;
reduce flue gas temperatures, thereby reducing gas cleaning costs;
replace recuperators that require complex repairs with more reliable ones;
successfully comply with the requirements of Law No. 261 Federal Law “On Energy Saving”;

Advantages of Finned Plate Heat Exchangers over traditional plate, rotary and shell-and-tube models

possibility of use in aggressive and abrasive environments, in environments with heavy gas contamination and dust;
increased operating temperature limits - up to 1250 C, while the service life of analog recuperators is reduced already at 800 C;
optimized dimensions and weight - 4-8 times lighter than analog recuperators;
significantly lower cost;
shortened payback periods;
low resistance values when air flows pass through the ducts;
improved design that prevents the accumulation of slag;
increased service life;
extended working period before preventive measures;
improved weight and size characteristics, facilitating installation and transportation of recuperators

Why can this type of recuperator be considered a smart choice?

increasing the area of the heat transfer surface per unit volume and mass;
high reliability of the recuperator used;
significant reduction in the possibility of recuperator failure due to abrasive wear and thermal deformation;
simplification of repair and maintenance processes for recuperators;
possibility of modular design and assembly of recuperators
The most common cases of using a recuperator.

Gas-to-gas heat exchangers are used in many areas, which can be divided into the following categories:

Processes having low level coolant temperature:

Interval from 20 to 60°C

for small volumes of gases, for example, as a flue gas utilizer when operating gas boilers in small room, where the heat exchanger is used in the ventilation system.
with large volumes of gases, for example, in the ventilation system of workshops, concert halls, indoor stadiums and other large premises.

Interval 60 to 200°C

for small volumes of gases, for example, to remove the smoke product of fuel combustion, which is released in the form of gas during many technological processes.
for large volumes of gases, for example, the use of a gas heat exchanger is possible in the ventilation system of drying and painting shops.

Processes having average level coolant temperature.

The range is from 200 to 600°C, an example would be the recovery of heat from flue gases during the operation of boiler houses, and it is also possible to save coal by redirecting excess heat to warm up the air supplied to the furnace.

Processes having high level coolant temperature.

The range is from 600 to 800°C; for example, in the production of plastics, a heat exchanger may be useful for cooling the gas or for recovering heat carried by flue gases.
The range is up to 1000°C and higher, which are observed in glass production, metallurgy, oil and gas refining and other areas of production, where the heat exchanger will become the basis for solving problems such as saving coal, or will act as a utilizer of generated flue gases.

It is worth noting that the use of a gas-gas heat exchanger at an exhaust gas temperature of 45-50°C requires a separate efficiency calculation.

conclusions

Installations with heat recovery can reduce energy costs for space heating by half. Their installation often pays for itself within the first heating season. Installing recuperators during construction and reconstruction allows us to partially reduce the load on the heating system of the entire building and eliminate a significant part of traditional heating equipment. The cost of installing recuperators is an investment not only in reducing heating costs, but also in ensuring optimal indoor climate conditions and, ultimately, in people's health.

Devices that can save heat and other types of energy are becoming increasingly important as energy prices are constantly rising. We have also long had no doubt about the need to breathe fresh, clean air indoors. The installation of popular plastic windows and hermetic doors. They disrupt air exchange and lead to undesirable consequences. Against the background of all these factors, ventilation systems with heat recovery come to our aid. They not only save us money, but also protect our health.