Centralized ventilation system. Forced ventilation device in a private house. The central ventilation system includes

There are two main features of objects of large area and volume regarding their effective ventilation. The first of them is obvious and is associated with the problems of organizing air exchange, which ensures a uniform distribution of fresh supply air over the area of ​​​​the room or in its individual microclimatic zones.

Wherein important point is also the rational use of thermal energy along the height of the room, in order to avoid large vertical temperature gradients, when superheated air accumulates under the ceiling, significantly increasing heat loss through the roof, instead of forming the necessary temperature regime in the work area.

The second feature is related to the fact that such objects, being very expensive, during their life cycle in some cases change their purpose several times due to changes in the intended use, technology of the work performed, or reorganization of the operating modes of buildings.

For example, a production machine shop can be converted into a social building. At the same time, it is desirable to preserve the existing ventilation system, limiting itself to organizational and structural reconfiguration at the level of the control system in order to avoid its radical reconstruction.

At the same time, it should be borne in mind that the objects under consideration can fundamentally differ from each other in terms of the requirements for microclimatic support systems. In this sense, supermarkets and hypermarkets differ significantly from pharmaceutical warehouses.

A trade fair complex, for example, has different ventilation requirements than pulp and paper mills, etc. At present, ventilation equipment is available (Fig. 1) that meets the indicated, seemingly incompatible features of the objects of the type under consideration.

Central and decentralized systems

When developing design solutions, one should distinguish between central and decentralized ventilation systems. The first of them assumes the presence of a high-capacity unit that processes air, which is then distributed using a duct system throughout the volume of the room.

The second ones are a set of physically autonomous units of relatively low productivity, located with a certain degree of uniformity over the area of ​​\u200b\u200bthe room directly under the ceiling. Decentralized systems, having a high adaptability, best meet the features of objects of large area and volume.

At the same time, as calculations show, as well as existing practical experience, decentralized systems are more economical in operation, providing a payback period for additional capital costs within 2-3 years, after which they begin to generate net profit. On fig. 2 shows a ventilation unit equipped with a recuperative plate heat exchanger, a heater and a direct cooling system with a condensing unit located on the roof.

Previously, decentralized systems were mainly used in industrial facilities. At present, thanks to the positively proven technical properties and positive economic indicators, decentralized ventilation is also being successfully implemented at social and utility facilities.

These include, for example, super and hypermarkets, markets, railway stations, major airports, sports complexes, exhibition halls, covered garages, etc. The main advantages of using such systems are as follows:

1. No need to use exhaust and/or supply air ducts.
2. Significantly reduced static head losses.
3. Possibility of realization of modes of supply of both heated and cooled air.
4. Absence of drafts (increased air mobility) in the working area.
5. Reducing the temperature gradient along the height of the room in the air heating mode.
6. Possibility of formation of various microclimatic zones within the given areas of one building volume.
7. The stability of the maintained microclimatic parameters, regardless of external dynamic influences (opening doors and windows, wind loads, etc.).
8. High reliability of the system as a whole. In the event of a temporary failure of a single unit, the system continues to function, being integrated at the top hierarchical control level. For the period of restoration work, the address of the defective unit is systematically blocked in the general list with subsequent removal of the blocking upon completion of the repair.
9. High energy efficiency due to improved air exchange, air recirculation and heat recovery, which helps to reduce equipment depreciation due to low operating costs.
10. No need to use supply and exhaust ventilation chambers.
11. Possibility of installation without stopping the main technological process;
12. Possibility of stage-by-stage equipment of the ventilation system by sequential expansion of both functionality and serviced production areas.

Decentralized ventilation systems are limited by the possibilities of their implementation in rooms with a ceiling height of 4.5 to 18 m and an area of ​​less than 100 m2. This is due to the aerodynamic features of the formation of vertical supply jets operating on the principle of air injection with a controlled swirl angle and a rarefaction core formed directly behind the nozzle exit.

Exhaust air contaminated with oils

One of the advantages of decentralized systems lies in the possibility of choosing ventilation units from a wide range of supplied models that meet the specific requirements of their application. In some cases, the presence of oil aerosol in the exhaust air is a significant problem.

Standard technical solutions in these circumstances are unacceptable due to the need for frequent replacement of filters and the destruction of sealing materials that are not sufficiently resistant to oils.

The oil-resistant models available as part of the supplied ventilation units provide a solution to this problem, having the ability to effectively capture oil aerosols and adequately drain their filter products.

Working in cold climates

For Russia, the performance of units at low temperatures is of particular importance, since a number of regions are located in the northeastern part, characterized by particularly severe climatic conditions. According to SNiP 23-01-99 "Construction climatology" in the area of ​​the pole of the course (Oymyakon), the estimated temperature of the coldest five-day period with a probability of 0.98 is -60°C. The standard version of the units allows their operation at outdoor temperatures down to -30°C.

The special version Cold Climate (CC-1) extends the operating limit of the units to -40°С, and the version Cold Climate (CC-2) - up to -60°С. The design of these units uses plastics that retain strength at low temperatures and do not crack in the cold. Instead of rubber shock absorbers, steel springs with silicone cups are used.

All sealing profiles are made of cold-resistant silicone. Air valve actuators are equipped with heating systems. Spring return actuators are installed for protection in the event of a power outage. The plate heat exchanger is sealed using a highly durable epoxy resin.

If the heat exchanger begins to freeze, the differential pressure differential sensor is triggered and the following sequence of actions starts: the outside air damper closes and the recirculation damper opens; the supply fan stops and the exhaust fan continues to operate; the bypass valve of the plate heat exchanger opens fully; warm air flow on the hood melts the ice and after an adjustable time delay and the return of the differential pressure differential sensor to its original state, the unit switches back to regular mode work. Frost protection of the air heater is carried out using a controller that monitors both the air temperature and the water temperature.

For this purpose, the end of the capillary tube stretched on the reverse side of the heater is inserted into the drain pipe. If the water temperature drops below 11°C, the mixing valve opens gradually. When the temperature drops below 5°C, the mixing valve is fully open and a frost alarm is given. When starting the unit and when switching from recirculation mode to one of the supply modes fresh air the system of smooth switching on of the supply fan is activated.

To ensure operation at outdoor air temperatures below -40°C (version CC-2), exhaust fan motors are additionally equipped with heating devices for periods of fan shutdown, which guarantees reliable start-up and operation of the unit at temperatures down to -60°C.

Work in explosive and flammable environments

In the presence of assigned categories of explosion and fire fire hazard A and B, regulated in accordance with the norms of NPB 105-03 "Determination of the categories of premises, buildings and outdoor installations for explosion and fire hazard", it is prohibited to use standard ventilation units located indoors for air heating purposes.

For these purposes, it is possible to use the specified units in a special EEX version, which, in accordance with the European standards DIN EN 60079-10 and VDE 0165 (part 101:1996-10), is certified for operation in zones 1 and 2. The indicated means that the units can be used in this execution when equipping rooms in which it is possible to form a flammable and explosive environment of class T3, which corresponds to an ignition temperature of combustible substances of more than 200 ° C.

The maximum allowable temperature of hot surfaces in this case is 200°C, which is according to GOST 51330.0-99 “Explosion-proof electrical equipment. General requirements» refers to explosion protection group II T3. The main differences between EEX and standard ventilation units are as follows:

• electrical components are replaced with explosion-proof ones;
• electrical circuits have the necessary galvanic isolation;
• materials capable of accumulating electrostatic charges are suitably protected or completely replaced.

In particular, the following activities have been carried out:

1. Fans are replaced with explosion-proof diagonal ones. The fan motors are equipped with temperature sensors type PTC with trigger protection device. The fan inlet is made of stainless steel and has a protective grille.
2. The contactor box is equipped with Ex cable glands with integral sealing ring and screw clamping device.
3. The sound-absorbing coating of the disc flow divider is pasted over with aluminum foil in order to prevent the accumulation of electrostatic charges, which is appropriately grounded.
4. Pocket type filters have an interwoven metal mesh that is grounded. The metal frame of the filter is also grounded.
5. The filter differential pressure sensor is mounted inside the control section but not connected. Electrical connection provided to the control cabinet during installation of the unit at the customer's site using an external galvanic isolation circuit.
6. The freezing thermostat is mounted in the heater section, but also not connected. Electrical connection is provided to the control cabinet during installation of the unit at the customer's site using an external galvanic isolation circuit.

In general, the units meet the requirements of GOST R 51330.13-99 “Explosion-proof electrical equipment. Electrical installations in hazardous areas" and Manual 13.91 "Fire requirements for heating, ventilation and air conditioning systems" to SNiP 2.04.05-91* "Heating, ventilation and air conditioning".

Comfortable environment in shopping centers increases sales

In the general range of units supplied, there are special models designed for the equipment of shopping centers (Fig. 3), the specifics of which are associated with the following circumstances:

1. Low ceiling height.
2. The need for minimal disruption to the interior.
3. Increased requirements for noise performance.

The above special models of ventilation units are structurally designed in such a way that in shopping room only injection type air distributors come out. Thus, the interior is preserved and the distance from the nozzle exit to the upper boundary of the working area is increased, which allows both heated and cooled air to be supplied into it without excessive mobility (drafts).

Since the fans are located above the roof, and the air distributor has a disk flow divider lined with a porous material that shields the penetration of sound into the hall, noise impacts are minimal. As a result, high level comfort that attracts shoppers, helps them stay longer in the mall and increase their purchases.

Consider installation and maintenance

Ease of installation and maintenance, as well as the required volume of these works are one of the indicators that characterize the ventilation system. Design solutions that provide for a decentralized ventilation system are implemented in the shortest possible time with a small volume installation work, since the supplied monoblocks go through a full cycle of assembly work at the factory.

The absence of air ducts and, accordingly, pressure losses to overcome aerodynamic resistance, which usually requires up to 80% of the consumed electrical energy, leads to the fact that the power of electric motors is low (maximum 3 kW) and the supply cables have a small cross section. As a result electrical installation is greatly simplified.

Hydraulic piping is also simplified due to the complete delivery of the assembled hydraulic module, which includes a three-way solenoid valve, as well as the necessary shut-off and control valves (balancing, air, shut-off, shut-off valves). The module is equipped with standard fittings on the inlet and outlet pipelines.

The binding of the automation system is reduced to a serial connection of the ventilation units to each other using a standard twisted pair. All work on network configuration is performed from the keyboard of a computer connected as one of the network nodes to a common bus. The three-level hierarchy created in this case is determined in a virtual way by assigning corresponding addresses to the network elements.

The mechanical installation of units providing for the supply of fresh air is carried out from the outside of the roof, which allows work to be carried out in as soon as possible without stopping ongoing production. The same applies to operational maintenance, the volumes of which are reduced to a minimum and are produced without disrupting the progress of the main technological operations.

Each unit serves an individual area, which allows the formation of zones with different temperature settings (comfort ventilation, standby heating, etc.), assigned operating modes (recirculation, fresh air supply, etc.) and different time schedules (single, two- or three-shift work).

The principle of flooding the working area with fresh air supplied and removed in compliance with a certain air balance for each of the individually serviced areas prevents unwanted flow of polluted air between them. Air supply directly to working area also increases the efficiency of assimilation of harmful emissions, actually reducing the concentration of gas and aerosol pollution to a minimum.

Profitable solution

Conceptually, decentralized ventilation in a number of applications is the optimal technical solution, providing not only functional advantages compared to centralized systems, but also more cost-effective, especially in terms of full life cycle operation of the equipment.

Decentralized ventilation has proven itself with positive side at numerous domestic and foreign facilities. Among Russian facilities, the most characteristic are large customs warehouses for finished products, spare parts, materials, semi-finished products, equipment, pharmaceuticals, etc.

They also include sports complexes, exhibition centers, showrooms, concert halls, large printing houses, hangars, equipment repair shops, carpentry and machine shops, etc. one;

Objects of large area and volume impose increased requirements on ventilation systems. Rice. 2;

The ventilation unit with built-in recuperative plate heat exchanger reduces operating costs to a minimum.

Modern construction projects often already include apartment ventilation systems. It is necessary, firstly, to minimize heat loss and achieve the required energy efficiency indicators, and secondly, to ensure high comfort, which is also an important characteristic of a modern house.

Modern apartment systems ventilation systems are extremely efficient: the heat exchanger recovers up to 98 percent of the heat contained in the exhaust air and uses it to heat the incoming fresh air. Thus, significant money savings are achieved due to the reduction in the need for energy consumption for heating. In addition, CO2 emissions are reduced, which also reduces the impact on environment. The features of central ventilation are described in the Benefits of Central Home Ventilation section.

Central ventilation at home is more common in new buildings

central system ventilation is quite often used in new buildings. Its installation is carried out already during the construction phase of the building frame. The air distribution system is installed in the floor structure in an insulating layer. Another possibility is laying in concrete. To do this, the ventilation pipes are integrated directly into the concrete ceiling. After the construction is completed, the pipes are hidden and cannot be seen. Therefore, the central ventilation system in a new building should always be planned in advance. In older buildings it is possible to use a central ventilation system, but the installation is somewhat more complicated. Requires intervention in building structures. In addition, you should consider how best to mask the air ducts.

Regardless of the application, homeowners should always trust the design and installation of a residential ventilation system to a specialized company. Trained technicians can accurately calculate all parameters of a ventilation system so that it works as efficiently as possible. What homeowners should consider when choosing the right ventilation system can be found in Buying Central Ventilation.

Central ventilation system at home

The central ventilation system in a building consists of a ventilation unit and an air distribution system. The air distribution system is hidden in the floor or built into the wall. Only the air outlets are visible. The air exchange is controlled independently by a central ventilation unit. This circumstance is described in detail in the section "How the ventilation of the central living room works."

European requirements for the energy efficiency of buildings require modern heat-insulating glazing and sealing of the outer shell, while the question of forced ventilation premises.

Central household unit ventilation unit can be installed under the roof, such as this model RecoVair.

In the future, controlled home ventilation may become a decisive factor in creating a comfortable microclimate in new buildings and energy upgraded buildings.

Global climate change and exploding fossil energy prices are tightening requirements to reduce losses through building ventilation systems.

Therefore, homeowners are striving to increase the thermal protection of windows and update doors. As a result, buildings become more airtight. In an effort to avoid wasteful use of thermal energy, residents ventilate the premises less often. high humidity leads to the appearance of mold, and that, in turn, to damage to building structures.

And this is a sustainable trend generated by the reduction of heating costs. Today, even in prosperous Germany, 22% of houses and 7 million apartments are affected by mold, while the burden of eliminating the consequences falls on the shoulders of homeowners or tenants.

Optimal air exchange

According to European building codes, when planning ventilation and technical measures, the degree of tightness of buildings is taken into account, in determining which a special calculation system is used. A specific hermetic shell assumes an appropriate air exchange regime necessary to protect building structures.

Today, this requirement is being implemented through a number of measures, including the automatic opening of windows. However, the most practical solution is the use of controlled forced ventilation with heat recovery, the installation of which takes into account the interaction of heating and ventilation equipment.

Significant savings on heating

Soon heating equipment will be focused on the specific energy consumption values ​​specified in the building's energy passport.

Today, when calculating the heating load and determining heat losses, the role of controlled ventilation is often not taken into account, which can lead to underinvestment in heating equipment.

For example, when equipping a house with a heat pump, this may mean using a smaller generator, as well as reducing the heat transfer surface of the collector or probe.

Controlled ventilation contributes not only to energy saving and compliance with sanitary and hygienic standards, but also to maintaining the integrity of building structures. In accordance with the new European regulation on energy saving, such installations may become part of the standard equipment of both new and retrofit buildings in the future.

Possible variants of the controlled ventilation system may have different designs.

1. Centralized supply and exhaust ventilation

Centralized ventilation is provided by a high-efficiency direct-flow fan with adjustable air flow. At the same time, the exhaust air is removed, and fresh air enters the building.

Central control ensures highly efficient heat recovery: the heat from the extract air passes through the heat exchanger and is transferred to the supply air. The better the thermal insulation of the building, the faster such an installation pays off.

Reuse of up to 95% of thermal energy provides highly efficient energy savings. In this case, the heat exchanger must be equipped with a function to prevent the formation of condensate and freezing. Centralized ventilation systems are equipped with dust filters.

2. Decentralized air handling unit

Such systems provide air exchange in one or two rooms. As a cheaper alternative to centralized systems, this solution creates a number of problems, such as the need for individual control in the bathroom or bedroom.

Typically, soundproof units with heat recovery function are mounted near windows and, in combination with heaters, heat the supply air. Air filtration capabilities depend on the features of the specific model.

3. Centralized exhaust unit

With a centralized version, an exhaust fan with a grill or poppet valve is used. It removes used air from the kitchen and bathroom, while a slight decrease in pressure is observed, which leads to the entry of fresh air through passively working anemostats in the outer walls.

In this system, the function of heat recovery through the use of a heat pump or regulation of the exhaust air volume is expedient, which ensures an optimal air exchange mode and energy savings. Installation work in this case is limited to the organization of a channel for the removal of air, while the inflow is carried out without special pipelines.

4. Decentralized exhaust unit

The soundproof exhaust fan is mounted on the outside wall of the kitchen or bathroom and provides exhaust air to the outside. Thanks to a slight decrease in pressure, fresh air enters the anemostats in the outer walls. Installation of the unit is less expensive than centralized systems, but there is no heat recovery.

Controlled ventilation with heat recovery provides a 20 percent savings in thermal energy directed to or any other building.

Option for a separate room.

Through the hole in the outer wall energy-saving direct-flow fan EcoVent sucks in atmospheric air. The highly efficient and large size aluminum plate heat exchanger ensures that over 70% of the thermal energy is reused.

Production shops, warehouses, super- and hypermarkets, sports complexes, exhibition halls and other objects of large area and volume impose increased, often specialized requirements on the ventilation systems that serve them.

There are two main features of objects of large area and volume regarding their effective ventilation.

The first of them is obvious and is associated with the problems of organizing air exchange, which ensures a uniform distribution of fresh supply air over the area of ​​​​the room or in its individual microclimatic zones. At the same time, an important point is also the rational use of thermal energy along the height of the room, in order to avoid large vertical temperature gradients, when overheated air accumulates under the ceiling, significantly increasing heat loss through the roof, instead of forming the necessary temperature regime in the working area.

The second feature is related to the fact that such objects, being very expensive, during their life cycle in some cases change their purpose several times due to changes in the intended use, technology of the work performed, or reorganization of the operating modes of buildings. For example, a production machine shop can be converted into a social building. At the same time, it is desirable to preserve the existing ventilation system, limiting itself to organizational and structural reconfiguration at the level of the control system in order to avoid its radical reconstruction. At the same time, it should be borne in mind that the objects under consideration can fundamentally differ from each other in terms of the requirements for microclimatic support systems. In this sense, super- and hypermarkets differ significantly from a pharmaceutical warehouse. A trade fair complex, for example, has different ventilation requirements than pulp and paper mills, etc.

At present, ventilation equipment is available (Fig. 1) that meets the indicated, seemingly incompatible features of the objects of the type under consideration.

Central and decentralized systems

When developing design solutions, one should distinguish between central and decentralized ventilation systems. The first of them assumes the presence of a high-capacity unit that processes air, which is then distributed using a duct system throughout the volume of the room. The second ones are a set of physically autonomous units of relatively low productivity, located with a certain degree of uniformity over the area of ​​​​the room directly under the ceiling. Decentralized systems, having a high adaptability, best meet the features of objects of large area and volume.

At the same time, as calculations show, as well as existing practical experience, decentralized systems are more economical in operation, providing a payback period for additional capital costs within 2-3 years, after which they begin to generate net profit.

On fig. 2 shows a ventilation unit equipped with a recuperative plate heat exchanger, a heater and a direct cooling system with a condensing unit located on the roof.

Previously, decentralized systems were mainly used in industrial facilities. At present, thanks to the positively proven technical properties and positive economic indicators, decentralized ventilation is also being successfully implemented at social and utility facilities. These include, for example, super- and hypermarkets, markets, train stations, major airports, sports complexes, exhibition halls, covered garages, etc.

The main advantages of using such systems are as follows:
1. No need to use exhaust and/or supply air ducts.
2. Significantly reduced static head losses.
3. Possibility to implement both heated and cooled air supply modes.
4. Absence of drafts (increased air mobility) in the working area.
5. Reducing the temperature gradient along the height of the room in the air heating mode.
6. Possibility of forming various microclimatic zones within the given areas of one building volume.
7. The stability of the maintained microclimatic parameters, regardless of external dynamic influences (opening doors and windows, wind loads, etc.).
8. High reliability of the system as a whole. In the event of a temporary failure of a single unit, the system continues to function, being integrated at the top hierarchical control level. For the period of restoration work, the address of the defective unit is systematically blocked in the general list with subsequent removal of the blocking upon completion of the repair.
9. High energy efficiency due to improved air exchange, air recirculation and heat recovery, which helps to reduce equipment depreciation due to low operating costs.
10. No need to use supply and exhaust ventilation chambers.
11. Possibility of installation without stopping the main technological process;
12. Possibility of stage-by-stage equipment of the ventilation system by successive expansion of both functionality and serviced production areas.

Decentralized ventilation systems are limited by the possibilities of their implementation in rooms with a ceiling height of 4.5 to 18 m and an area of ​​less than 100 m2. This is due to the aerodynamic features of the formation of vertical supply jets operating on the principle of air injection with a controlled swirl angle and a rarefaction core formed directly behind the nozzle exit.

Exhaust air contaminated with oils

One of the advantages of decentralized systems lies in the possibility of choosing ventilation units from a wide range of supplied models that meet the specific requirements of their application. In some cases, the presence of oil aerosol in the exhaust air is a significant problem.

Standard technical solutions in these circumstances are unacceptable due to the need for frequent replacement of filters and the destruction of sealing materials that are not sufficiently resistant to oils. The oil-resistant models available as part of the supplied ventilation units provide a solution to this problem, having the ability to effectively capture oil aerosols and adequately drain their filter products.

Working in cold climates

For Ukraine, the performance of units at low temperatures is of particular importance, since a number of regions are located in the northeastern part, characterized by particularly harsh climatic conditions. The standard version of the units allows their operation at outdoor temperatures down to -30 °С. The special version Cold Climate (CC-1) extends the operating capacity of the units to -40 °С, and the version Cold Climate (CC-2) - up to -60 °С.

The design of these units uses plastics that retain strength at low temperatures and do not crack in the cold. Instead of rubber shock absorbers, steel springs with silicone cups are used. All sealing profiles are made of cold-resistant silicone. Air valve actuators are equipped with heating systems. Spring return actuators are installed for protection in the event of a power outage.

The plate heat exchanger is sealed using a highly durable epoxy resin.

If the heat exchanger begins to freeze, the differential pressure differential sensor is triggered and the following sequence of actions starts:
- the outside air damper closes and the recirculation damper opens; the supply fan stops and the exhaust fan continues to operate;
- the bypass valve of the plate heat exchanger opens fully;
- warm air flow on the hood melts the ice and after an adjustable time delay and the return of the differential pressure differential sensor to its original state, the unit switches back to normal operation.

Frost protection of the air heater is carried out using a controller that monitors both the air temperature and the water temperature. For this purpose, the end of the capillary tube stretched on the reverse side of the heater is inserted into the drain pipe. If the water temperature falls below 11 °C, the mixing valve opens gradually. When the temperature drops below 5°C, the mixing valve is fully open and a frost alarm is given. When the unit is started and when switching from recirculation mode to one of the fresh air supply modes, the soft start system of the supply fan is activated. To ensure operation at outdoor air temperatures below -40 °C (version CC-2), exhaust fan motors are additionally equipped with heating devices for fan off periods, which guarantees reliable start-up and operation of the unit at temperatures down to -60 °C.

Work in explosive and flammable environments

If there are assigned categories of explosion and fire hazard A and B, regulated in accordance with the norms of NPB 105-03 "Definition of categories of premises, buildings and outdoor installations for explosion and fire hazard", it is prohibited to use standard ventilation units located indoors for the purposes of air heating . For these purposes, it is possible to use the specified units in a special EEX version, which, in accordance with the European standards DIN EN 60079-10 and VDE 0165 (part 101:1996-10), is certified for operation in zones 1 and 2. The indicated means that the units can be used in this execution when equipping rooms in which it is possible to form a fire hazardous and explosive environment of class T3, which corresponds to an ignition temperature of combustible substances of more than 200 ° C. The maximum allowable temperature of hot surfaces is 200 °C.

The main differences between EEX and standard ventilation units are as follows:
- electrical components are replaced with explosion-proof ones;
- electrical circuits have the necessary galvanic isolation;
- materials capable of accumulating electrostatic charges are suitably protected or completely replaced.

In particular, the following activities have been carried out:
1. Fans are replaced with explosion-proof diagonal ones. The fan motors are equipped with PTC type temperature sensors with trigger protection device. The fan inlet is made of stainless steel and has a protective grille.
2. The contactor box is equipped with Ex-cable glands with compound sealing ring and screw clamping device.
3. The noise-absorbing coating of the disc flow divider is pasted over with aluminum foil in order to prevent the accumulation of electrostatic charges, which is appropriately grounded.
4. Pocket type filters have an interwoven metal mesh that is grounded. The metal frame of the filter is also grounded.
5. The filter differential pressure sensor is mounted inside the control section but not connected. Electrical connection is provided to the control cabinet during installation of the unit at the customer's site using an external galvanic isolation circuit.
6. The freezing thermostat is mounted in the heater section, but also not connected. Electrical connection is provided to the control cabinet during installation of the unit at the customer's site using an external galvanic isolation circuit.

Comfortable environment in shopping centers increases sales

In the general range of units supplied, there are special models designed for the equipment of shopping centers (Fig. 3), the specifics of which are associated with the following circumstances:
1. Low ceiling height.
2. The need for minimal disruption of the interior.
3. Increased requirements for noise characteristics.

The special models of ventilation units mentioned above are structurally designed in such a way that only injection-type air distributors go into the sales area. Thus, the interior is preserved and the distance from the nozzle exit to the upper boundary of the working area is increased, which allows both heated and cooled air to be supplied into it without excessive mobility (drafts). Since the fans are located above the roof, and the air distributor has a disk flow divider lined with a porous material that shields the penetration of sound into the hall, noise impacts are minimal. As a result, a high level of comfort is achieved, which attracts customers, contributes to their longer stay in the shopping center and increased purchases.

Stages of design, installation and maintenance

Ease of installation and maintenance, as well as the required volume of these works are one of the indicators that characterize the ventilation system. Design solutions that provide for a decentralized ventilation system are implemented in the shortest possible time with a small amount of installation work, since the supplied monoblocks go through a full cycle of assembly work at the manufacturing plant.

The absence of air ducts and, accordingly, pressure losses to overcome aerodynamic resistance, which usually requires up to 80% of the consumed electrical energy, leads to the fact that the power of electric motors is low (maximum 3 kW) and the supply cables have a small cross section. As a result, electrical installation is greatly simplified.

Hydraulic piping is also simplified due to the complete delivery of the assembled hydraulic module, which includes a three-way solenoid valve, as well as the necessary shut-off and control valves (balancing, air, shut-off, shut-off valves). The module is equipped with standard fittings on the inlet and outlet pipelines.

The binding of the automation system is reduced to a serial connection of the ventilation units to each other using a standard twisted pair. All work on network configuration is performed from the keyboard of a computer connected as one of the network nodes to a common bus. The three-level hierarchy created in this case is determined in a virtual way by assigning corresponding addresses to the network elements.

The mechanical installation of units providing fresh air supply is carried out from the outside of the roof, which makes it possible to carry out work in the shortest possible time without stopping the existing production. The same applies to operational maintenance, the volume of which is reduced to a minimum and is carried out without disrupting the progress of the main technological operations.

On fig. 4 shows the work to replace the filters placed in the upper part of the units located on the roof.

Each unit serves an individual area, which allows the formation of zones with different temperature settings (comfort ventilation, standby heating, etc.), assigned operating modes (recirculation, fresh air supply, etc.) and different time schedules (single, two- or three-shift work). The principle of flooding the working area with fresh air supplied and removed in compliance with a certain air balance for each of the individually serviced areas prevents unwanted flow of polluted air between them. The air supply directly to the working area also increases the efficiency of the assimilation of harmful emissions, in fact, reducing the concentration of gas and aerosol pollution to a minimum.

Profitable solution

Conceptually, decentralized ventilation in a number of applications is the optimal technical solution that provides not only functional advantages compared to centralized systems, but also more economically advantageous, especially in terms of the full life cycle of equipment operation.

Decentralized ventilation has proven itself on the positive side in numerous domestic and foreign facilities. Among Russian facilities, the most characteristic are large customs warehouses for finished products, spare parts, materials, semi-finished products, equipment, pharmaceuticals, etc. They also include sports complexes, exhibition centers, showrooms, concert halls, large printing houses, hangars, equipment repair shops, carpentry and machine shops, etc.