The creation of an energy efficient administrative building, which will be as close as possible to the PASSIVE HOUSE standard, is impossible without a modern air handling unit (AHU) with heat recovery.
Under recuperation means the process of utilizing the heat of the internal extract air with a temperature t in, emitted during a cold period with a high temperature outside, to heat the supply outside air. The process of heat recovery takes place in special heat exchangers: plate recuperators, rotating regenerators, as well as in heat exchangers installed separately in air streams with different temperatures (in exhaust and supply units) and connected by an intermediate heat carrier (glycol, ethylene glycol).
The latter option is most relevant in the case when the inflow and exhaust are spaced apart along the height of the building, for example, the supply unit is in the basement, and the exhaust unit is in the attic, however, the recovery efficiency of such systems will be much lower (from 30 to 50% in comparison with the PVU in one body
Plate recuperators are a cassette in which the supply and exhaust air channels are separated by aluminum sheets. Heat exchange takes place between the supply and extract air through the aluminum sheets. The internal extract air heats the external supply air through the heat exchanger fins. In this case, the process of air mixing does not occur.
V rotary recuperators heat transfer from the extract air to the supply air is carried out through a rotating cylindrical rotor consisting of a package of thin metal plates. During the operation of the rotary recuperator, the exhaust air heats the plates, and then these plates move into the flow of cold outside air and heat it up. However, in the flow separation units, due to their leakage, the exhaust air flows into the supply air. The percentage of overflow can be from 5 to 20%, depending on the quality of the equipment.
To achieve this goal - to bring the building of FGAU "NII CEPP" closer to passive, during long discussions and calculations, it was decided to install supply and exhaust ventilation units with a recuperator. The Russian manufacturer of energy-saving climate systems - the company TURKOV.
Company TURKOV produces PVU for the following regions:
- For the Central region (equipment with two-stage recuperation ZENIT series which works stably down to -25 O C, and is excellent for the climate of the Central region of Russia, efficiency 65-75%);
- For Siberia (equipment with three-stage recuperation Zenit HECO series works stably up to -35 O C, and is excellent for the climate of Siberia, however, it is often used in the central region, the efficiency is 80-85%);
- For the Far North (equipment with four-stage recuperation CrioVent series works stably up to -45 O C, excellent for extremely cold climates and is used in the most severe regions of Russia, efficiency up to 90%).
However, the TURKOV PVU uses enthalpy plate recuperator, in which along with the transfer of implicit heat from the extract air, moisture is also transferred to the supply air.
The working area of the enthalpy recuperator is made of a polymer membrane that passes water vapor molecules from the extract (humidified) air and transfers it to the supply (dry) air. There is no mixing of the exhaust and supply flows in the recuperator, since moisture is passed through the membrane by diffusion due to the difference in vapor concentration on both sides of the membrane.
The dimensions of the membrane cells are such that only water vapor can pass through it; for dust, pollutants, water droplets, bacteria, viruses and odors, the membrane is an insurmountable obstacle (due to the ratio of the size of the membrane “cells” and other substances).
Enthalpy recuperator in fact, it is a plate recuperator, where a polymer membrane is used instead of aluminum. Since the thermal conductivity of the membrane plate is less than that of aluminum, the required area of the enthalpy recuperator is much larger than the area of a similar aluminum recuperator. On the one hand, this increases the dimensions of the equipment, on the other hand, it allows a large amount of moisture to be transferred, and it is due to this that it is possible to achieve high frost resistance of the recuperator and stable operation of the equipment at ultra-low temperatures.
In winter (outside temperature is below -5C), if the extract air humidity exceeds 30% (at an extract air temperature of 22 ... 24oC), in the recuperator along with the transfer of moisture to the supply air, the process of moisture accumulation on the recuperator plate takes place. Therefore, it is necessary to periodically turn off the supply fan and dry the hygroscopic layer of the recuperator with the extract air. The duration, frequency and temperature below which the drying process is required depends on the stage of the recuperator, the temperature and humidity inside the room. The most frequently used heat exchanger drying settings are shown in Table 1.
Table 1. The most frequently used settings for drying the heat exchanger
| Recuperator stages | Temperature / Humidity | ||||
|
|
<20% | 20%-30% | 30%-35% | 35%-45% | |
| 2 steps | not required | 3/45 minutes | 3/30 minutes | 4/30 minutes | |
| 3 steps | not required | 3/50 minutes | 3/40 minutes | 3/30 minutes | |
| 4 steps | not required | 3/50 minutes | 3/40 minutes | ||
Drying out the recuperator is required only when installing air humidification systems, or when operating equipment with large, systematic moisture inflows.
- Drying mode is not required for standard indoor air conditions.
In this article, as an example of an administrative building, a typical five-story building of the Federal State Autonomous Institution "NII CEPP" after the planned reconstruction is considered.
For this building, the flow rate of the supply and exhaust air was determined in accordance with the norms of air exchange in the administrative premises for each room of the building.
The total values of the supply and exhaust air flow rates for the floors of the building are shown in Table 2.
Table 2. Estimated flow rates of supply / extract air by floors of the building
| Floor | Supply air consumption, m 3 / h | Exhaust air consumption, m 3 / h | PVU TURKOV |
| Basement | 1987 | 1987 | Zenit 2400 HECO SW |
| 1st floor | 6517 | 6517 |
Zenit 1600 HECO SW Zenit 2400 HECO SW Zenit 3400 HECO SW |
| 2nd floor | 5010 | 5010 | Zenit 5000 HECO SW |
| 3rd floor | 6208 | 6208 |
Zenit 6000 HECO SW Zenit 350 HECO MW - 2 pcs. |
| 4th floor | 6957 | 6957 | Zenit 6000 HECO SW Zenit 350 HECO MW |
| 5th floor | 4274 | 4274 |
Zenit 6000 HECO SW Zenit 350 HECO MW |
In the laboratories of the PVU they work according to a special algorithm with compensation for the exhaust from the fume cupboards, i.e. when any fume cupboard is switched on, the exhaust of the PVU is automatically reduced by the amount of the cupboard exhaust. The Turkov air handling units were selected based on the estimated costs. Each floor will be served by its own PSU Zenit HECO SW and Zenit HECO MW with three-stage heat recovery up to 85%.
Ventilation of the first floor is carried out by PVUs, which are installed in the basement and on the second floor. Ventilation of the remaining floors (except for laboratories on the fourth and third floors) is provided by PVU installed on the technical floor.
The external view of the PVU of the Zenit Heco SW unit is shown in Figure 6. Table 3 shows the technical data for each PVU of the unit.
Installation Zenit Heco SW includes: - Heat and noise insulation;
- Supply fan;
- Exhaust fan;
- Supply filter;
- Exhaust filter;
- 3-stage recuperator;
- Water heater;
- Mixing unit;
- Automation with a set of sensors;
- Wired control panel.
An important plus is the ability to mount equipment both vertically and horizontally under the ceiling, which is used in the building in question. And also the ability to locate equipment in cold areas (attics, garages, technical rooms, etc.) and on the street, which is very important in the restoration and reconstruction of buildings.
PSU Zenit HECO MW - small PSU with heat and moisture recovery with a water heater and a mixing unit in a lightweight and versatile casing made of expanded polypropylene, designed to maintain the climate in small rooms, apartments, houses.
Company TURKOVindependently developed and manufactures Monocontroller automation for ventilation equipment in Russia. This automation is used in the Zenit Heco SW PVU
- The controller controls the electronically commutated fans via the MODBUS line, which makes it possible to monitor the operation of each fan.
- Controls water heaters and chillers to accurately maintain the supply air temperature in both winter and summer seasons.
- For CO control 2 in the conference hall and meeting rooms, the automation is equipped with special CO sensors 2 ... The equipment will monitor the CO concentration 2 and automatically change the air flow according to the number of people in the room to maintain the required air quality, thereby reducing the heat consumption of the equipment.
- A complete dispatching system makes it as simple as possible to organize a dispatching point. A remote monitoring system will allow you to monitor equipment from anywhere in the world.
Control panel capabilities:
- Clock, date;
- Three fan speeds;
- Display of filter status in real time;
- Weekly timer;
- Setting the supply air temperature;
- Display of faults on the display.
Efficiency mark
To assess the efficiency of the installation in the considered building of Zenit Heco SW air handling units with recuperation, we determine the calculated, average and annual loads on the ventilation system, as well as costs in rubles for the cold period, warm period and for the whole year for three variants of the PES:
- HPU with recuperation Zenit Heco SW (recuperator efficiency 85%);
- Direct-flow PVU (i.e. without a recuperator);
- PVU with heat recovery efficiency 50%.
The load on the ventilation system is the load on the air heater, which heats up (during the cold period) or cools (during the warm period) the supply air after the recuperator. In the direct-flow PVU in the heater, the air is heated from the initial parameters corresponding to the parameters of the outside air in the cold period, and it is cooled during the warm period. The results of calculating the calculated load on the ventilation system during the cold season for the floors of the building are shown in Table 3. The results of calculating the calculated load on the ventilation system during the warm season for the entire building are shown in Table 4.
Table 3. Estimated load on the ventilation system during the cold period by floors, kW
| Floor | PVU Zenit HECO SW / MW | Direct-flow PVU | PVU with 50% recuperation |
| Basement | 3,5 | 28,9 | 14,0 |
| 1st floor | 11,5 | 94,8 | 45,8 |
| 2nd floor | 8,8 | 72,9 | 35,2 |
| 3rd floor | 10,9 | 90,4 | 43,6 |
| 4th floor | 12,2 | 101,3 | 48,9 |
| 5th floor | 7,5 | 62,2 | 30,0 |
| 54,4 | 450,6 | 217,5 |
Table 4. Estimated load on the ventilation system during the warm period by floors, kW
| Floor | PVU Zenit HECO SW / MW | Direct-flow PVU | PVU with 50% recuperation |
| 20,2 | 33,1 | 31,1 |
Since the calculated outside air temperatures during the cold and warm periods are not constant during the heating and cooling periods, it is necessary to determine the average ventilation load at the average outside temperature:
The results of calculating the annual load on the ventilation system during the warm period and the cold period for the entire building are shown in Tables 5 and 6.
Table 5. Annual load on the ventilation system during the cold season by floors, kW
| Floor | PVU Zenit HECO SW / MW | Direct-flow PVU | PVU with 50% recuperation |
| 66105 | 655733 | 264421 | |
| 66,1 | 655,7 | 264,4 |
Table 6. Annual load on the ventilation system during the warm period by floors, kW
| Floor | PVU Zenit HECO SW / MW | Direct-flow PVU | PVU with 50% recuperation |
| 12362 | 20287 | 19019 | |
| 12,4 | 20,3 | 19,0 |
Let's determine the costs in rubles per year for heating, cooling and fan operation.
Consumption in rubles for reheating is obtained by multiplying the annual values of ventilation loads (in Gcal) during the cold period by the cost of 1 Gcal / hour of heat energy from the network and by the time the PVU operates in heating mode. The cost of 1 Gcal / h of heat energy from the network is taken equal to 2169 rubles.
The costs in rubles for the operation of fans are obtained by multiplying their power, operating time and the cost of 1 kW of electricity. The cost of 1 kWh of electricity is assumed to be 5.57 rubles.
The results of calculating the costs in rubles for the operation of the PES in the cold period are shown in Table 7, and in the warm period in Table 8. Table 9 shows a comparison of all variants of the PES for the entire building of the FGAU "NII TsEPP".
Table 7. Expenses in rubles for the year for the operation of the PSU in the cold season
| Floor | PVU Zenit HECO SW / MW | Direct-flow PVU | PVU with 50% recuperation | |||
| For heating | On fans | For heating | On fans | For heating | On fans | |
| Total costs | 368 206 | 337 568 | 3 652 433 | 337 568 | 1 472 827 | 337 568 |
Table 8. Expenses in rubles for the year for the operation of the PSU during the warm period
| Floor | PVU Zenit HECO SW / MW | Direct-flow PVU | PVU with 50% recuperation | |||
| For cooling | On fans | For cooling | On fans | For cooling | On fans | |
| Total costs | 68 858 | 141 968 | 112 998 | 141 968 | 105 936 | 141 968 |
Table 9. Comparison of all PES
| The magnitude | PVU Zenit HECO SW / MW | Direct-flow PVU | PVU with 50% recuperation |
| , kW | 54,4 | 450,6 | 217,5 |
| 20,2 | 33,1 | 31,1 | |
| 25,7 | 255,3 | 103,0 | |
| 11,4 | 18,8 | 17,6 | |
| 66 105 | 655 733 | 264 421 | |
| 12 362 | 20 287 | 19 019 | |
| 78 468 | 676 020 | 283 440 | |
| Heating costs, rub | 122 539 | 1 223 178 | 493 240 |
| Cooling costs, rub | 68 858 | 112 998 | 105 936 |
| Fan costs in winter, rub | 337 568 | ||
| Fan costs in summer, rub | 141 968 | ||
| Total annual costs, rub | 670 933 | 1 815 712 | 1 078 712 |
Analysis of Table 9 allows us to make an unambiguous conclusion - the Zenit HECO SW and Zenit HECO MW air handling units with heat and moisture recovery are very energy efficient.
The total annual ventilation load of the TURKOV PVU is less than the load in the PVU with an efficiency of 50% by 72%, and in comparison with the direct-flow PVU by 88%. The Turkov PSU will save 1 million 145 thousand rubles - in comparison with the direct-flow PSU or 408 thousand rubles - in comparison with the PSU, the efficiency of which is 50%.
Where else are the savings ...
The main reason for failures in the use of systems with recuperation is the relatively high initial investment, but with a more complete look at the costs of development, such systems not only quickly pay off, but also reduce the total investment during development. As an example, we take the most massive "typical" development with the use of residential, office buildings and shops.
Average heat loss of finished buildings: 50 W / m 2.
- Included: Heat loss through walls, windows, roofing, foundations, etc.
Included:
- Ventilation of apartments, calculated according to the purpose of the premises and frequency.
- Ventilation of offices based on the number of people and CO2 compensation.
- Ventilation of shops, corridors, warehouses, etc.
- The area ratio was selected based on several existing complexes
Included:
- Compensation for bathrooms, bathrooms, kitchens, etc. Since it is impossible to organize suction from these rooms into the recuperation system, an inflow is organized into this room, and the exhaust goes by separate fans past the recuperator.
The difference between the amount of supply air and the amount of air to be compensated.
It is this volume of extract air that transfers heat to the supply air.
So, it is necessary to build up the area with standard buildings with a total area of 40,000 m 2 with the specified heat loss characteristics. Let's see how the use of ventilation systems with recuperation will save money.
Operating costs
The main goal of choosing systems with recuperation is to reduce the cost of operating the equipment by significantly reducing the required thermal power for heating the supply air.
With the use of supply and exhaust ventilation units without recuperation, we will obtain a heat consumption of the ventilation system of one building of 2410 kW ∙ h.
- Let's take the cost of operating such a system as 100%. At the same time, there is no savings at all - 0%.
With the use of type-setting supply and exhaust ventilation units with heat recovery and an average efficiency of 50%, we will get the heat consumption of the ventilation system of one building 1457 kW ∙ h.
- Operating cost 60%. Savings with typesetting equipment 40%
With the use of monoblock highly efficient supply and exhaust ventilation units TURKOV with heat and moisture recovery and an average efficiency of 85%, we will obtain a heat consumption of the ventilation system of one building of 790 kW ∙ h.
- Operating cost 33%. Savings with TURKOV equipment 67%
As you can see, ventilation systems with highly efficient equipment have lower heat consumption, which allows us to talk about the payback period of equipment in 3-7 years when using water heaters and 1-2 years when using electric heaters.
Building costs
If building is carried out in a city, then it is necessary to release a significant amount of thermal energy from the existing heating network, which always requires significant financial costs. The more heat is required, the more expensive the summing up cost will be.
Development "in the field" often does not imply heat supply, usually gas is supplied and the construction of its own boiler house or CHP is carried out. The cost of this structure is proportional to the required thermal power: the more, the more expensive.
As an example, suppose that a boiler house with a capacity of 50 MW of thermal energy has been built.
In addition to ventilation, the cost of heating a typical building with an area of 40,000 m 2 and a heat loss of 50 W / m 2 will be about 2,000 kWh.
With the use of supply and exhaust ventilation systems without recuperation, it will be possible to construct 11 buildings.
With the use of type-setting supply and exhaust ventilation units with heat recovery and an average efficiency of 50%, it will be possible to construct 14 buildings.
With the use of monoblock highly efficient supply and exhaust ventilation units TURKOV with heat and moisture recovery and an average efficiency of 85%, it will be possible to construct 18 buildings.
The final estimate for the supply of more heat energy or the construction of a high-capacity boiler house is significantly more expensive than the cost of more energy-efficient ventilation equipment. With the use of additional means to reduce the heat loss of a building, it is possible to increase the building without increasing the required heat output. For example, having reduced heat loss by only 20%, to 40 W / m 2, it will already be possible to build 21 buildings.
Features of equipment operation in northern latitudes
As a rule, equipment with recuperation has restrictions on the minimum outdoor air temperature. This is due to the capabilities of the recuperator and the limitation is -25 ... -30 o C. If the temperature drops, the condensate from the extract air will freeze on the recuperator, therefore, at extremely low temperatures, an electric preheater or a water preheater with antifreeze liquid is used. For example, in Yakutia, the design temperature of outdoor air is -48 o C. Then the classic systems with recuperation work as follows:
- o With pre-heater up to -25 o C (Heat energy is expended).
- C -25 o The air is heated in the recuperator to -2.5 o C (at an efficiency of 50%).
- C -2.5 o The air is heated by the main heater to the required temperature (heat energy is expended).
When using a special series of equipment for the Far North with a 4-stage recuperation TURKOV CrioVent, no preheating is required, since 4 stages, a large recuperation area and moisture return prevent the recuperator from freezing. The equipment works in a gray manner:
- Outdoor air with a temperature of -48 o C heats up in the recuperator up to 11.5 o С (efficiency 85%).
- C 11.5 o The air is heated by the main heater to the required temperature. (Heat energy is expended).
The absence of preheating and high efficiency of the equipment will significantly reduce heat consumption and simplify the design of the equipment.
The use of highly efficient recuperation systems in northern latitudes is most relevant, since, due to low outdoor air temperatures, the use of classical recuperation systems is difficult, and equipment without recuperation requires too much heat energy. Turkov equipment successfully works in cities with the most difficult climatic conditions, such as: Ulan-Ude, Irkutsk, Yeniseisk, Yakutsk, Anadyr, Murmansk, as well as in many other cities with a milder climate in comparison with these cities.
Conclusion
- The use of ventilation systems with recuperation allows not only to reduce operating costs, but in the case of large-scale reconstruction or capital development cases, to reduce the initial investment.
- The maximum savings can be achieved in mid and northern latitudes, where equipment operates in harsh conditions with prolonged negative outdoor temperatures.
- On the example of the building of the Federal State Autonomous Institution "NII TsEPP", a ventilation system with a highly efficient recuperator will save 3 million 33 thousand rubles per year - in comparison with a direct-flow PVU and 1 million 40 thousand rubles a year - in comparison with a type-setting PVU, the efficiency of which is 50%.
Supply and exhaust ventilation with heat recovery is a system that allows you to establish a reliable change of exhaust air in a room. The installation of the equipment allows heating the air entering the room using the temperature of the outgoing flow. The costs of purchasing and installing the system quickly pay off.
It is important to know the main points when selecting and installing equipment.
What is heat recovery?
In the air recuperator, the heat of the exhaust gases is removed. The two streams are separated by a wall through which heat exchange occurs between moving air streams in a constant direction. An important characteristic of the equipment is the efficiency level of the recuperator. This value for different types of equipment is in the range of 30-95%. This value is in direct proportion to:
- designs and types of recuperator;
- the temperature difference between the heated outgoing air and the temperature of the carrier behind the heat exchanger device;
- accelerating the flow through the heat exchanger.
Advantages and disadvantages of a ventilation system with a heat exchanger
Such equipment allows:
- make a constant change of air masses in a room of various sizes;
- if the residents need it, it is possible to supply a heated stream;
- there is a constant purification of the incoming oxygen;
- if desired, it is possible to install equipment with the ability to humidify the air in the premises; in such systems, a channel is provided for removing condensate;
- with heat recovery and selection of equipment of sufficient capacity, a significant reduction in the cost of paying for electricity is possible.
Among the shortcomings of the system, several points can be distinguished:
- increased noise level during the operation of fans;
- when installing cheap equipment, there is no opportunity to cool the incoming air during the hot period;
- it is required to constantly monitor and drain condensate.
The principle of operation of the ventilation system
Such ventilation with heat recovery allows, to reduce the load on the air conditioning system of buildings during the hot season. The conditioned air from the room, when passing through the heat exchanger, lowers the temperature of the atmospheric stream from the street. In winter, the heating of the outboard flow takes place according to this scheme.
Installation in buildings with a large area and a general air conditioning system is especially relevant. In such places, the level of air exchange can exceed 700-800 m 3 / h. Such installations have impressive dimensions, so you will need to prepare a separate room in the basement, on the basement or attic. If installation in an attic is required, additional sound insulation will be required to prevent heat loss and condensation in the ducts.
The ventilation system with recuperation is manufactured in several types, we will analyze the advantages and disadvantages of each of them.
Air recovery device types
For a better comparison, we present the types of recuperators in a separate table.
| type of instalation | Short description | Dignity | disadvantages |
| Plate with plastic and metal plates | Outgoing and incoming flow passes on both sides of the plates. The average level of efficiency is 50-75%. | The streams do not touch directly. There are no moving parts in the circuit, so this design is reliable and durable. | Not identified |
| Lamellar, with ribs made of water-conducting materials. | The efficiency of the devices is 50-75%, the air flows pass from both sides. | There are no moving parts. The streams of air masses are not in contact with each other. There is no condensation in the system. | There is no possibility of air dehumidification in the manned room. |
| Rotary | High level of efficiency 75-85%. The streams pass through separate foil-lined channels. | Significantly saves energy, is able to reduce the humidity in the serviced premises. | Mixing of air masses and penetration of unpleasant odors are possible. Requires maintenance and repair of a complex design with rotating parts. |
| Air recuperator with the action of an intermediate heat carrier | A solution of water and glycol is used as a heat carrier or filled with purified water. In such a scheme, the outgoing gas gives off heat to the water, which heats up the incoming stream. Designed for maintenance of industrial premises. | There is no contact of the streams, therefore, their mixing and the flow of exhaust gases are excluded. | Low level of efficiency |
| Chamber recuperators | A damper is installed in the chamber of the device, which can increase the value of the passing flow and change its direction vector. | Due to its design features, this type of equipment has a high level of efficiency, 70-80%. | The streams are in contact, therefore contamination of the incoming air is possible. |
| Heat pipe | The device is equipped with a system of tubes filled with freon. | There are no moving mechanisms, the service life is increased. The air comes in clean, there is no contact between the streams. | Low level of efficiency, it is 50-70%. |
A recuperation unit with heat pipes is produced for individual small rooms in a building. They do not require a duct system. But in this case, if the distance between the streams is insufficient, it is possible to remove the incoming streams and the absence of circulation of air masses.
List of possible problems after installing the system
Critical problems if recuperative ventilation is installed in the building. The main malfunctions are eliminated by the manufacturers of systems under warranty, but a few "troubles" can darken the joy of the owners of buildings and premises, after installing the equipment of the supply and exhaust ventilation system. These include:
- Possibility of condensation formation. When air flows with a high heating temperature pass and come into contact with cold atmospheric air, water drops fall out on the walls of the chamber in a closed chamber. At freezing temperatures outside, the fins of the heat exchanger freeze up, and the movement of flows is disrupted, the efficiency of the system decreases. With complete freezing of the channels, the device may stop working.
- The energy efficiency level of the system. Supply and exhaust systems equipped with additional heat exchangers of various types require electricity to operate. Therefore, it is required to carry out accurate calculations of various types of equipment specifically for the room that will be serviced by the system.
You should not save money when buying, and purchase a device in which the level of energy savings will exceed the cost of operating the equipment.
- The full payback period for the air ventilation system. The period of full refund of funds spent on the purchase and installation of equipment directly depends on the previous paragraph. It is important for the consumer that these costs are recouped over a 10-year period. Otherwise, equipping a room or building with an expensive ventilation system is not cost-effective.
During this period, it will be necessary to make repairs and possible replacement of system parts and additional costs for their purchase and payment for their replacement.
Ways to prevent freezing of the recuperator
Some types of devices are made taking into account the prevention of strong freezing of the surfaces of the heat exchanger. At low temperatures outside, the build-up of ice can completely block the access of fresh air to the room. Some systems begin to overgrow with a crust of ice when the outside temperature drops below 0 0.
In this case, the flow leaving the room is cooled to a temperature below the dew point and the surfaces begin to freeze. To resume the operation of the device, it will be necessary to raise the temperature of the incoming stream to positive values. The ice crust will collapse and the equipment will be able to continue working.
To avoid such situations, air handling units with a built-in heat recuperator can be protected from such a breakdown using several methods:
- additional equipment of the unit with an electric air heater may be required to protect the device. It prevents the outgoing air masses from cooling below the dew point and prevents the appearance of water droplets and the formation of ice;
- The most reliable method, which excludes the possibility of freezing of the recuperator fins, is to equip the device with an electronic defrosting circuit control system, which is switched on taking into account several parameters. To do this, it may be necessary to set a date for the electric heaters of the incoming air to be put into operation, at the first subzero temperatures.
You can install a sensor that reacts to cold air and turns on air heating elements in the ventilation system. In any case, the operation of air-heating devices in ventilation is cyclical, only in the cold season. When the supply ventilation is turned on, the incoming flow and the exhaust gases discharged from the room are heated.
After a certain period of time, the supply fan turns off. At this time, in the recuperator, the incoming flow is heated by the temperature of the outgoing air, which is displaced by the exhaust fan. This principle of operation of the heating circuit works in automatic mode throughout the cold season.
To prevent the formation of ice on the device, we recommend purchasing a plate type recuperator with plastic fins.
Method for self-calculating the power of supply and exhaust ventilation
First of all, it is necessary to determine the volume of all air flows required to create comfortable conditions. This can be done in several ways:
- You can make a calculation based on the total area of the building, excluding the residents living. Here, such a calculation scheme is used - within an hour, for each m2 of the total area, 3 m3 of air should be supplied.
- Based on sanitary standards, for a comfortable stay, for each person living in the room, at least 60 m 3 must be received within an hour, for incoming guests it is necessary to add another 20 m 3.
- Based on the building standards of 2.08.01-89, the norms for the frequency of air replacement in a room of a certain area within an hour have been developed. Here the calculation is made taking into account the purpose of the buildings. To do this, it is necessary to determine the product of the frequency of complete changes of air masses and the volume of the entire room or building.
In conclusion, we note.
Regardless of the pronunciation of the word ventilation, in English or other languages, the main task of the supply and exhaust system with a heat recuperator is to create comfortable conditions for people in the room. Therefore, having decided on the calculation of the required power and the type of heat exchanger, you can safely proceed to equipping the house with a reliable ventilation system.
To increase the service life, filters can be added to the circuit to purify the air. But it should be remembered that it is easier to prevent breakdowns by carrying out timely maintenance and care than spending money on repairs or buying new equipment.
general information
The service life of the equipment for the ventilation unit manufactured by our company is established subject to the observance of the operating rules and the timely replacement of filters and parts with a limited resource. The list of such parts and their resource is indicated in the User's Guide for each specific model.
In order to avoid misunderstandings, we kindly ask you to carefully study the User Manual, pay attention to the conditions for the occurrence of warranty obligations, and check the correctness of filling out the warranty card. The warranty card is valid only if there are correctly and clearly indicated: model, serial number of the product, date of sale, clear seals of the seller, the installer, and the buyer's signature. The model and serial number of the product must correspond to those indicated in the warranty card.
Warranty Limitations
In case of violation of these conditions, as well as in the case when the data specified in the warranty card is changed, erased or rewritten, the warranty card is invalidated.
In this case, we recommend that you contact the seller to obtain a new warranty card that meets the above conditions. If the date of sale cannot be established, in accordance with consumer protection legislation, the warranty period starts from the date of manufacture of the product.
The recuperators have a 7-year warranty.
The 7-year warranty applies to equipment operated in accordance with all operating rules specified in the "ZENIT Equipment Operation Manual". The warranty does not apply to equipment operated in rooms with high humidity (swimming pools, saunas, rooms with a humidity of more than 50% in winter), but the warranty can be maintained if the equipment is equipped with a duct dehumidifier.
Delivery in Moscow and the Moscow region up to 10 km from the Moscow Ring Road
Delivery times are indicated on the card of each product. Shipping costs are paid separately. Delivery is carried out by a transport company.
Delivery to regions
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general information
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It is possible to create a comfortable microclimate in the premises of the house only with appropriate ventilation. Stagnant air can cause mold on the walls and cause physical discomfort. An open window or window cannot always qualitatively renew the air in the premises of a private house. To do this effectively, you need to install a supply and exhaust ventilation system.
The principle of operation and the need for supply and exhaust ventilation in a private house
This type of ventilation is also called "forced". Unlike the version with natural circulation, it is equipped with electrical appliances that pump and advance air flows.
Constructions with a forced air exchange system are equipped with fans of various capacities, electronics, silencers and heating elements. All these devices are designed to supply the home with environmentally friendly oxygen, creating internal comfort and a feeling of freshness.
The presence of these elements will create effective ventilation in the house.
Unlike natural ventilation, the supply and exhaust type of air exchange is effective under the following conditions:
- The minimum temperature difference indoors and outdoors, when the warm air rises, cannot create draft.
- With a difference in air pressure between the upper and lower levels of the building.
This type of ventilation must be used for residential premises or buildings with several rooms located at different levels, as well as in areas with a polluted atmosphere. The supply and exhaust ventilation method will not only change the air in the room, but also make it clean, thanks to the special filters provided in the system.
The design can carry out not only the usual filtration through the foam rubber layer, but also carry out this process using a lamp with an ultraviolet glow.
Effective forced ventilation system
An important role in the supply and exhaust system is played by:
- motor and fan power;
- filter material class;
- the size of the heating element;
- quality of material and type of air ducts.
Fans
Forced movement of air masses is provided by fans. Simple models are equipped with three levels of blade speed:
- normal;
- low (used for "quiet" work at night or during the absence of the owners);
- high, (used to create powerful air currents).
Modern fan models are made with a large number of speeds, which meets the needs of any owner. The fans are retrofitted with automatic and electronic controllers. This makes it possible to program the device by setting the speed modes of the rotation of the blades. Electrical equipment allows you to synchronize ventilation with the "smart home" system.
When choosing, preference should be given to trusted manufacturers
Since the operation of the ventilation system is designed for a continuously long period of time, the quality of the fans must be at the highest level.
Filters
Supply air masses must be cleaned with filters. The recuperators are equipped with filter beds capable of retaining particles less than 0.5 microns. This parameter complies with the European standard. A filter with such a capacity does not allow fungal spores, plant pollen, dry soot and dust to enter the room.
The presence of this device is especially important for owners suffering from allergic diseases.
The design of ventilation ducts can be equipped with several filtering barriers, mounted in front of heat exchangers. However, such filters are designed to protect them from carrier dirt by exhaust streams.
Made with multiple layers
The recuperation systems are equipped with electronic sensors, which, having registered the maximum degree of filter contamination, signal with an audible or light indicator.
Heating elements
The supply and exhaust ventilation system requires the installation of heating elements, since heat exchangers lose their efficiency if the outside air temperature is below -10 ° C. For this, an electric heating system for the supplied air is mounted on the supply duct.
Modern heating elements are programmed for a specific operating mode. This makes it possible to control the temperature without outside interference. Typically, computerized heating elements are installed and synchronized with the smart home system.
The size, power, shape and design of heating elements are selected in compliance with the parameters of the entire ventilation system and the desire of the owner.
Make the temperature comfortable
When choosing the power of the heater, you should take into account its operation at an external low temperature and high humidity. Such conditions will contribute to the fact that condensate may appear on the parts of the heat exchanger, which subsequently turns into ice. This problem can be solved in two ways:
- Change the order of operation of the supply fan. It must be turned on every 20-30 minutes for 5-10 minutes. The heated air flow passing through the heat exchanger prevents icing.
- Change the direction of the flow of cold air. To do this, the supply air masses are separated by directing their flows past the heat exchanger.
Air ducts
It is most convenient to install ventilation in a building under construction - in basements, attics or behind suspended panels. It should be noted that the installation of this system must be carried out in a dry and insulated room with a positive temperature.
The most convenient and popular ducts are flexible aluminum or plastic options. Pipes are made with round, square or rectangular sections. This material has a reinforcing steel wire frame, and can also be covered with a thermal insulation layer based on mineral fibers, for example, mineral wool.
Supply and exhaust ventilation with heat recovery
Such a system implies its operation in the colder months. To prevent incoming air flows from causing cold in the house, the system must be upgraded with a heat exchanger - an air recuperator. The device gives off heat to cold air at the time of disposal of the outgoing air.
The humid air concentrated in the kitchen, bathroom or utility room is directed outside using the air intakes. Before leaving the air duct channels, it is retained in the heat exchanger, which takes some of the heat, giving it to the opposite (intake movement of air masses).
A good recovery option with partial moisture return is implemented in Naveka units, Node5 series: https://progress-nw.ru/shop?part=UstanovkiventilyatsionnyieNode5.
How the device works
Systems equipped with recuperators have become very popular in Western Europe. Thanks to this equipment, buildings constructed in these regions lose 5-10 times less heat than those erected without these systems. Utilization of heated exhaust streams reduced heat generation costs by 65–68%. This made it possible to recoup such a system in a period of 4–5 years. The energy efficiency of houses that are equipped with this system made it possible to reduce the heating period.
The dimensions and power of the supply and exhaust systems equipped with a recuperator depend on the area and location of the ventilated premises.
Enterprising homeowners install natural and forced (with heat recovery) in their homes. This is necessary in case of malfunction or repair of the mechanical air exchange. Natural ventilation is convenient to use during unheated periods.
When using two ventilation systems in your home, you should adhere to the rule - the air ducts of natural ventilation must be tightly closed during the operation of forced air exchange.
If this is neglected, then the quality of air renewal with the help of the supply and exhaust system will significantly decrease.
The following types of recuperators are most often used in ventilation systems:
- lamellar;
- rotary;
- with intermediate heat carrier;
- chamber;
- in the form of heat pipes.
Plate recuperators
In this device, warm and cold air flows pass from both sides of the plates. This contributes to the formation of condensation on them. In this regard, special outlets for accumulated water are installed on such structures. Moisture collection chambers should be equipped with seals to prevent liquid from entering the channel. If water drops enter the system, ice may form. Therefore, for the normal operation of the device, a defrosting system is required.
The formation of ice can be avoided by controlling the operation of the bypass valve, which regulates the amount of air flow through the device.
The design feature increases its efficiency
Rotary
Heat exchange in this device occurs through the removed and supply channels as a result of the rotation of the rotor discs. The elements of this system are not protected from dirt and odors, so their particles can move from one air stream to another.
The recovery of warm air flows can be controlled by varying the speed of rotation of the rotor discs.
This device, unlike the previous one, is less prone to freezing, since the working elements are movable in dynamics. The efficiency of these devices reaches 75–85%.
Equipped with movable elements
Recuperators with intermediate heat carrier
The heat carrier in this design of the recuperator is water or water-glycol solution. The peculiarity of this type is that heat exchangers in different channels - one in the exhaust, the other in the supply. Water flows through tubes between two heat exchangers. The design has a closed system. This excludes the ingress of contaminants from the exhaust air into the supply air.
Heat exchange is regulated by changing the speed of movement of the heat carrier moisture.
Such devices do not provide for moving elements, so their efficiency is lower, which is 45-60%.
Has no moving parts
Chamber
The exchange of heat in such a structure occurs as a result of a change in the direction of the air flow. Chamber recuperators are devices, usually in the form of a rectangular parallelepiped, with a chamber, which are divided into two parts by a damper. During operation, it changes the direction of the air masses so that the temperature of the supply flow rises from the heated chamber body. The disadvantage of this recuperator is that dirty particles and odors can mix with the extract and supply air.
The flows inside the chamber can be mixed
Heat pipes
Recuperators of this type have a sealed body, inside which a system of tubes filled with freon is installed. Under the influence of high temperature (in the process of air removal), the substance turns into steam. At the moment of the passage of the inflow masses along the pipes, the steam collects in droplets, forming a liquid. The design of such recuperators excludes the transfer of odors and dirt. Since the body of this device has no moving parts, it has a low efficiency (45–65%).
The work is based on temperature changes in freon
Due to their high efficiency, the most popular are rotor and plate types. The design of the recuperators can be modernized, for example, by installing two plate-type heat exchangers in series. The efficiency of this ventilation increases.
PVU design
When designing a ventilation system, it is necessary to determine the type of this device, since not every owner may be suitable for its power and the amount of electricity consumed. In this regard, if there is no need for forced ventilation, then it is better to install natural ventilation.
Each ventilation system has its own standard parameters for the volume of air passed in 1 hour:
- for the natural variant, this rate is 1m³ / h;
- for forced - in the range from 3 to 5 m³ / h.
When a ventilation system is being designed for large rooms, it is advisable to install forced ventilation.
The design and installation of ventilation systems is a technically complex process that includes several stages:
- The first stage consists of drawing up drawings and collecting data on the layout of the premises. Based on the established information, the type of ventilation system is selected, and the capacity of the equipment is determined.
- At the second stage, the necessary calculations are made for the volume of air exchange for each room in the house. This is a crucial design moment, since incorrect calculations, in the future, will cause stagnant air, the appearance of mold and mildew and a feeling of stuffiness.
- The third stage is to carry out cross-section calculations for air ducts. This is also an important point, since incorrect calculations will cause low efficiency of the entire system, despite the expensive equipment. Therefore, it is better to entrust the calculations to specialists than to do it yourself. To correctly calculate the size of the ducts, follow the basic rules:
- in a natural hood, the air flow rate must correspond to 1m / s;
- in air ducts equipped with fans, this parameter is 5 m / s;
- in the branches of the air ducts the speed of air masses is 3 m / s.
- At the fourth stage, a diagram of the ventilation system is drawn up, indicating the separation valves. The purpose of this stage is to properly distribute the barriers to prevent the spread of smoke and fire in a fire.
- The fifth stage is to harmonize the selected system with the current regulatory documents and installation and placement rules. The finished design of the ventilation system must be approved by the fire, sanitary and hygienic and architectural organization. Obtaining permits from all these services and government agencies gives the right to install.
Pay attention to the material on the design and installation of ventilation in the cellar of a private house:.
Calculations
When calculating the supply and exhaust ventilation systems, it is necessary to take into account the amount of changeable air in the room for a certain time. The unit is cubic meter per hour (m³ / h).
To apply this indicator to the calculations, you need to calculate the passage of air flows and add 20% (the resistance of the filter layers and gratings).
Air volume calculation
As an example, we calculated the air volume for a private house with a ceiling height of 2.5 m. The system will also serve 3 bedrooms (11 m² each), an entrance hall (15 m²), a toilet (7 m²) and a kitchen (9 m²). Substitute the values (3 ∙ 11 + 15 + 7 + 9) ∙ 2.5 = 160 m³.
When making calculations, it is necessary to round up the received data upward.
The installed recuperator must match the capacity of all fans in the supply and exhaust system. To do this, subtract 25% from the sum of the fans' performance (air flow resistance in the system). The inlet and outlet of the recuperator must be equipped with fans.
It should be noted that in each room of the house where the system is located, 1 supply and 1 exhaust fan must be installed. The required performance of each of them is calculated as follows:
- Bedroom: 11 ∙ 2.5 = 27.5 + 20% = 33 m³ / h. Since the house has three bedrooms with the same area, it is necessary to multiply this value by three: 33 ∙ 3 = 99 m³ / h.
- Hallway: 15 ∙ 2.5 = 37.5 + 20% = 45 m³ / h.
- Toilet: 7 ∙ 2.5 = 17.5 + 20% = 21 m³ / h.
- Kitchen: 9 ∙ 2.5 = 22.5 + 20% = 27 m³ / h.
Now you need to add these values to get the total fan capacity: 99 + 45 + 21 + 27 = 192 m³ / h.
The load on the recuperator will be: 192–25% = 144 m³ / h.
Calculation of the diameter of the ventilation duct
To calculate the diameter of the ventilation duct, it is necessary to use the formula for calculating the cross-sectional area, which looks as follows: F = L / (S ∙ 3600), where L is the total amount of air masses passing in one hour, S is the average air velocity equal to 1 m / s. Substitute the values: 192 / (1 m / s ∙ 3600) = 0.0533 m².
To calculate the radius of a round pipe, use the following formula: R = √ (F: π), where R is the radius of a round pipe; F - section of the duct; π is a mathematical value equal to 3.14. For example, it looks like this: √ (0.0533 ∙ 3.14) = 0.167 m².
Electricity calculation
Correctly calculated energy consumption will allow rational use of the ventilation system. This is especially important if the duct structure is equipped with heating elements.
To calculate the amount of energy consumed, use the formula: M = (T1 ∙ L ∙ C ∙ D ∙ 16 + T2 ∙ L ∙ C ∙ N ∙ 8) ∙ AD: 1000, where M is the total price for the used electricity; Т1 and Т2 - temperature difference in the day and night period (the values differ depending on the month of the year); D, N - the cost of electricity in accordance with the time of day; A, D - total number of calendar days in a month.
Temperature readings are easy to find from local weather forecasts, so there is no need to purchase any reference books. The rates are determined in accordance with the region of residence. Using these sources, you can get accurate readings of energy consumption during the operation of the ventilation system.
Equipment installation procedure
The installation of the equipment elements of the supply and exhaust ventilation system of the premises is carried out after the walls are finished, before the installation of the suspended ceiling panels. The ventilation system equipment is installed in a certain order:
- The intake valve is mounted first.
- After it - a filter for cleaning the incoming air.
- Then an electric heater.
- The heat exchanger is a recuperator.
- Air duct cooling system.
- If necessary, the system is equipped with a humidifier and a fan in the supply duct.
- If the power is high, then a noise isolating device is installed.
Diy installation of a supply and exhaust ventilation system
Installation of a ventilation system consists of several construction stages:
- Using the previously obtained values, calculate the optimal parameters for the holes in the wall.
- Make a markup to accommodate the supply duct. To drill a hole in a concrete wall, a concrete drill must be used. This device is fixed to the wall, so that the hole is flat, in a precisely marked place. The point of contact between the core drill and the concrete wall is insulated with a special cap, to which pipes with a water jet and a powerful vacuum cleaner are attached.
Provides forced movement of air masses
Installation of air ducts
The installation of air ducts should be preceded by the drawing up of diagrams and drawings. And you should also take care of the availability of additional fasteners and clamps. Installation of air ducts is carried out in the following order:
How to operate and maintain a PES
The high-quality operation of the supply and exhaust ventilation system depends not only on professional installation, but also on competent service. The elements of the supply and exhaust device require:
- periodic cleaning of filters;
- their renewal, in case of contamination or expiration of their service life;
- replacing the lubricant of the moving parts and parts of the fans;
- if the system is equipped with heating elements, ionizers and noise isolators, it is necessary to regularly check their serviceability.
Usually, all the necessary steps to take care of this system are described in the operating rules and instructions.
Video: ventilation of an apartment on 2 levels with heat recovery
Having familiarized yourself with all the nuances of the installation and equipment of the ventilation system, you can create a healthy and comfortable atmosphere in your home, providing yourself and your loved ones with fresh air.