Supply and exhaust unit is a modern solution for organizing optimal air exchange and rational use of energy resources. The principle of operation is to force the influx and removal of air outside the room. Based on the installation's PVC, you can create an individual microclimate system by connecting various filters and devices.

Recuperation ventilation system

To save thermal energy, some PES installations are equipped with recuperators. The recuperator is a metal heat exchanger that is integrated into the ventilation system and partially heats the outside air due to the removed warm air. In this case, the bulk of the air flow is heated by a conventional air heater. Although the price of a supply and exhaust unit with heat recovery is higher than for other devices, due to energy efficiency these costs quickly pay off. An important characteristic of the device is its efficiency factor, which ranges from 30 to 96% depending on the type of recuperator, the speed of air flow through the heat exchanger and the temperature difference.

Supply and exhaust ventilation with recovery fully meets modern requirements for saving thermal energy. And thanks to the room heating function, it is considered the most promising development in the field of ventilation.

Main advantages:

1. Comfortable air exchange
2. Efficient energy saving
3. Humidity control function
4. Reliable sound insulation
5. High efficiency up to 96%
6. Convenient control system
7. Air purification from dust and impurities
8. Maximum thermal energy conservation

Classification and characteristics of devices.

Depending on the design of the heat exchanger, a heat exchanger with a recuperator can be of several types:

Plate recuperators are the most common design. Heat exchange occurs by passing air through a series of plates. During operation, condensate forms, so the recovery system is additionally equipped with a condensate drain. Efficiency is 50-75%.

A rotary type heat recuperator is a device cylindrical, densely filled with layers of corrugated steel. Heat exchange is carried out due to a rotating rotor, which sequentially passes first warm and then cold air. In this case, the intensity depends on the rotor rotation speed. The supply and exhaust system with recovery of this type has big sizes, therefore suitable for shopping centers, hospitals, hotels and other large areas. Due to the absence of freezing, efficiency reaches 75-85%

Less common types include recuperators with an intermediate coolant (this can be water or a water-glycol solution). Efficiency is 40-60%. A supply and exhaust unit with a recuperator can be made in the form of heat pipes filled with freon. The efficiency of such a device is 50-70%. In addition, a chamber recuperator is used. Cold and warm air pass through one chamber, which is separated by a special damper. Periodically, the damper turns over and the air flows change places. Efficiency is up to 90%.

Supply and exhaust ventilation with heat recovery best price!

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Thanks to the convenient search form you can easily find suitable model and buy an air handling unit with recovery at the best price!

Due to the increase in tariffs for primary energy resources, recovery has become more relevant than ever. In air handling units with recovery, the following types of recuperators are usually used:

• plate or cross-flow recuperator;
• rotary recuperator;
• recuperators with intermediate coolant;
• Heat pump;
• chamber type recuperator;
• recuperator with heat pipes.

Principle of operation

The operating principle of any recuperator in air handling units is as follows. It provides heat exchange (in some models - both cold exchange and moisture exchange) between the supply and exhaust air flows. The heat exchange process can occur continuously - through the walls of the heat exchanger, using freon or an intermediate coolant. Heat exchange can also be periodic, as in a rotary and chamber recuperator. As a result, the exhaust air is cooled, thereby heating the fresh supply air. The cold exchange process in certain models of recuperators takes place during the warm season and makes it possible to reduce energy costs for air conditioning systems due to some cooling of the supply air supplied to the room. Moisture exchange occurs between the exhaust and supply air flows, allowing you to maintain comfortable humidity in the room all year round, without the use of any additional devices - humidifiers and others.

Plate or cross-flow recuperator.

The heat-conducting plates of the recuperative surface are made of thin metal (material - aluminum, copper, stainless steel) foil or ultra-thin cardboard, plastic, hygroscopic cellulose. The supply and exhaust air flows move through many small channels formed by these heat-conducting plates in a counterflow pattern. Contact and mixing of flows and their contamination are practically excluded. There are no moving parts in the recuperator design. Efficiency rate 50-80%. In a metal foil recuperator, due to the difference in air flow temperatures, moisture may condense on the surface of the plates. In the warm season, it must be drained into the building's sewerage system through a specially equipped drainage pipeline. In cold weather, there is a danger of this moisture freezing in the recuperator and causing mechanical damage (defrosting). In addition, the formed ice greatly reduces the efficiency of the recuperator. Therefore, when operating in the cold season, heat exchangers with metal heat-conducting plates require periodic defrosting with a flow of warm exhaust air or the use of an additional water or electric air heater. In this case, supply air is either not supplied at all, or is supplied to the room bypassing the recuperator through an additional valve (bypass). Defrost time averages from 5 to 25 minutes. A heat exchanger with heat-conducting plates made of ultra-thin cardboard and plastic is not subject to freezing, since moisture exchange occurs through these materials, but it has another drawback - it cannot be used for ventilation of rooms with high humidity in order to dry them. The plate recuperator can be installed in supply and exhaust system both in vertical and horizontal positions, depending on the requirements for the size of the ventilation chamber. Plate recuperators are the most common due to their relative simplicity of design and low cost.

Rotary recuperator.

This type is the second most widespread after the lamellar type. Heat from one air flow to another is transferred through a cylindrical hollow drum, called a rotor, rotating between the exhaust and supply sections. The internal volume of the rotor is filled with tightly packed metal foil or wire, which plays the role of a rotating heat transfer surface. The material of the foil or wire is the same as that of the plate recuperator - copper, aluminum or stainless steel. The rotor has a horizontal axis of rotation of the drive shaft, rotated by an electric motor with stepper or inverter control. The engine can be used to control the recovery process. Efficiency rate 75-90%. The efficiency of the recuperator depends on the flow temperatures, their speed and rotor speed. By changing the rotor speed, you can change the operating efficiency. Freezing of moisture in the rotor is excluded, but mixing of flows, their mutual contamination and transfer of odors cannot be completely excluded, since the flows are in direct contact with each other. Mixing up to 3% is possible. Rotary heat exchangers do not require large amounts of electricity and allow you to dry air in rooms with high humidity. The design of rotary recuperators is more complex than plate recuperators, and their cost and operating costs are higher. However, air handling units with rotary heat exchangers are very popular due to their high efficiency.

Recuperators with intermediate coolant.

The coolant is most often water or aqueous solutions of glycols. Such a recuperator consists of two heat exchangers connected by pipelines with a circulation pump and fittings. One of the heat exchangers is placed in a channel with the exhaust air flow and receives heat from it. The heat is transferred through the coolant using a pump and pipes to another heat exchanger located in the supply air channel. The supply air receives this heat and heats up. Mixing of flows in this case is completely excluded, but due to the presence of an intermediate coolant, the efficiency coefficient of this type of recuperator is relatively low and amounts to 45-55%. Efficiency can be influenced using a pump by influencing the speed of coolant movement. The main advantage and difference between a recuperator with an intermediate coolant and a recuperator with a heat pipe is that the heat exchangers in the exhaust and supply units can be located at a distance from each other. The installation position for heat exchangers, pumps and pipelines can be either vertical or horizontal.

Heat pump.

Relatively recently, an interesting type of recuperator with an intermediate coolant has appeared - the so-called. a thermodynamic recuperator in which the role of liquid heat exchangers, pipes and a pump is played by a refrigeration machine operating in heat pump mode. This is a kind of combination of a recuperator and a heat pump. It consists of two refrigerant heat exchangers - an evaporator-air cooler and a condenser, pipelines, a thermostatic valve, a compressor and a 4-way valve. Heat exchangers are located in the supply and exhaust air ducts, a compressor is necessary to ensure circulation of the refrigerant, and the valve switches the refrigerant flows depending on the season and allows heat to be transferred from the exhaust air to the supply air and vice versa. In this case, the supply and exhaust system can consist of several supply and one exhaust unit of higher capacity, united by one refrigeration circuit. At the same time, the capabilities of the system allow several air handling units to operate in different modes (heating/cooling) simultaneously. The conversion coefficient of the COP heat pump can reach values ​​of 4.5-6.5.

Recuperator with heat pipes.

According to the principle of operation, a recuperator with heat pipes is similar to a recuperator with an intermediate coolant. The only difference is that not heat exchangers are placed in the air flows, but so-called heat pipes or, more precisely, thermosyphons. Structurally, these are hermetically sealed sections of copper finned pipe, filled inside with a specially selected low-boiling freon. One end of the pipe in the exhaust flow heats up, the freon boils in this place and transfers the heat received from the air to the other end of the pipe, blown by the flow of supply air. Here the freon inside the pipe condenses and transfers heat to the air, which heats up. Mutual mixing of flows, their pollution and transfer of odors are completely excluded. There are no moving elements; pipes are placed in flows only vertically or at a slight slope so that the freon moves inside the pipes from the cold end to the hot end due to gravity. Efficiency rate 50-70%. An important condition for ensuring its operation: the air ducts in which the thermosiphons are installed must be located vertically one above the other.

Chamber type recuperator.

The internal volume (chamber) of such a recuperator is divided into two halves by a damper. The damper moves from time to time, thereby changing the direction of movement of the exhaust and supply air flows. The exhaust air heats one half of the chamber, then the damper directs the flow of supply air here and it is heated by the heated walls of the chamber. This process is repeated periodically. The efficiency ratio reaches 70-80%. But the design has moving parts, and therefore there is a high probability of mutual mixing, contamination of flows and transfer of odors.

Calculation of recuperator efficiency.

In the technical characteristics of recuperative ventilation units of many manufacturing companies, as a rule, two values ​​of the recovery coefficient are given - by air temperature and its enthalpy. The efficiency of a recuperator can be calculated based on temperature or air enthalpy. Calculation by temperature takes into account the sensible heat content of the air, and by enthalpy, the moisture content of the air (its relative humidity) is also taken into account. Calculation based on enthalpy is considered more accurate. For the calculation, initial data is required. They are obtained by measuring the temperature and humidity of the air in three places: indoors (where the ventilation unit provides air exchange), outdoors and in the cross section of the supply air distribution grille (from where the processed air enters the room). outside air). The formula for calculating the recovery efficiency by temperature is as follows:

Kt = (T4 – T1) / (T2 – T1), Where

• Kt– recuperator efficiency coefficient by temperature;
• T1– outside air temperature, oC;
• T2– temperature of the exhaust air (i.e. indoor air), °C;
• T4– supply air temperature, oC.

Enthalpy of air is the heat content of air, i.e. the amount of heat contained in it per 1 kg of dry air. Enthalpy is determined using the i-d diagram of the state of moist air, plotting on it the points corresponding to the measured temperature and humidity in the room, outside and supply air. The formula for calculating the recovery efficiency based on enthalpy is as follows:

Kh = (H4 – H1) / (H2 – H1), Where

• Kh– recuperator efficiency coefficient in terms of enthalpy;
• H1– enthalpy of outside air, kJ/kg;
• H2– enthalpy of exhaust air (i.e. indoor air), kJ/kg;
• H4– enthalpy of supply air, kJ/kg.

Economic feasibility of using air handling units with recovery.

As an example, let’s take a feasibility study for the use of ventilation units with recovery in the supply and exhaust ventilation systems of a car dealership.

Initial data:

• object – car showroom with a total area of ​​2000 m2;
• the average height of the premises is 3-6 m, consists of two exhibition halls, an office area and a service station (STS);
• For supply and exhaust ventilation of these premises, duct-type ventilation units were selected: 1 unit with an air flow rate of 650 m3/hour and a power consumption of 0.4 kW and 5 units with an air flow rate of 1500 m3/hour and a power consumption of 0.83 kW.
• The guaranteed range of external air temperatures for ducted installations is (-15…+40) оС.

To compare energy consumption, we will calculate the power of a duct electric air heater, which is necessary to heat the outside air in the cold season in a traditional type air-handling unit (consisting of a check valve, a duct filter, a fan and an electric air heater) with an air flow rate of 650 and 1500 m3/hour, respectively. At the same time, the cost of electricity is 5 rubles per 1 kW*hour.

The outside air must be heated from -15 to +20°C.

The power of the electric air heater was calculated using the heat balance equation:

Qн = G*Cp*T, W, Where:

• Qн– air heater power, W;
• G- mass air flow through the air heater, kg/sec;
• Wed– specific isobaric heat capacity of air. Ср = 1000kJ/kg*K;
• T– difference in air temperature at the outlet of the air heater and the inlet.

T = 20 – (-15) = 35 oC.

1. 650 / 3600 = 0.181 m3/sec

p = 1.2 kg/m3 – air density.

G = 0.181*1.2 = 0.217 kg/sec

Qn = 0.217*1000*35 = 7600 W.

2. 1500 / 3600 = 0.417 m3/sec

G = 0.417*1.2 = 0.5 kg/sec

Qn = 0.5*1000*35 = 17500 W.

Thus, the use of ducted units with heat recovery in the cold season instead of traditional ones using electric air heaters makes it possible to reduce energy costs with the same amount of supplied air by more than 20 times and thereby reduce costs and accordingly increase the profit of a car dealership. In addition, the use of recovery units makes it possible to reduce the consumer's financial costs for energy resources for heating premises in the cold season and for air conditioning in the warm season by approximately 50%.

For greater clarity, we will carry out a comparative financial analysis of the energy consumption of supply and exhaust ventilation systems for car dealership premises, equipped with duct-type heat recovery units and traditional units with electric air heaters.

Initial data:

System 1.

Installations with heat recovery with a flow rate of 650 m3/hour – 1 unit. and 1500 m3/hour – 5 units.

The total electrical power consumption will be: 0.4 + 5*0.83 = 4.55 kW*hour.

System 2.

Traditional ducted supply and exhaust ventilation units - 1 unit. with a flow rate of 650m3/hour and 5 units. with a flow rate of 1500m3/hour.

Total electric power installation at 650 m3/hour will be:

• fans – 2*0.155 = 0.31 kW*hour;
• automation and valve drives – 0.1 kW*hour;
• electric air heater – 7.6 kW*hour;

Total: 8.01 kW*hour.

The total electrical power of the installation at 1500 m3/hour will be:

• fans – 2*0.32 = 0.64 kW*hour;
• automation and valve drives – 0.1 kW*hour;
• electric air heater – 17.5 kW*hour.

Total: (18.24 kW*hour)*5 = 91.2 kW*hour.

Total: 91.2 + 8.01 = 99.21 kW*hour.

We assume the period of use of heating in ventilation systems is 150 working days per year for 9 hours. We get 150*9 =1350 hours.

Energy consumption of installations with recovery will be: 4.55 * 1350 = 6142.5 kW

Operating costs will be: 5 rubles * 6142.5 kW = 30712.5 rubles. or in relative terms (to the total area of ​​the car dealership of 2000 m2) 30172.5 / 2000 = 15.1 rub./m2.

Energy consumption of traditional systems will be: 99.21 * 1350 = 133933.5 kW Operating costs will be: 5 rubles * 133933.5 kW = 669667.5 rubles. or in relative terms (to the total area of ​​the car dealership of 2000 m2) 669667.5 / 2000 = 334.8 rubles/m2.

It is well known that there are several types of room ventilation systems. The most widespread is natural ventilation, when the inflow and outflow of air is carried out through ventilation shafts, open windows and windows, as well as through cracks and leaks in structures.

Of course, natural ventilation is necessary, but its operation is associated with a lot of inconvenience, and it is almost impossible to achieve cost savings with its installation. Yes, and calling the movement of air through slightly open windows and doors ventilation is a stretch - most likely, it will be ordinary ventilation. To achieve the required intensity of air mass circulation, windows must be open around the clock, which is unattainable in the cold season.

That is why the device of forced or mechanical ventilation is considered a more correct and rational approach. Sometimes without forced ventilation it is simply impossible to get by, most often they resort to its arrangement in production premises with deteriorated working conditions. Let's leave industrialists and production workers aside and turn our attention to residential buildings and apartments.

Often, in pursuit of savings, cottage owners country houses or apartments, they invest a lot of money in insulating and sealing the housing and only then realize that due to the lack of oxygen it is difficult to stay in the room.

The solution to the problem is obvious - you need to arrange ventilation. The subconscious mind tells you that the best option There will be an energy-saving ventilation device. The lack of properly designed ventilation can cause your home to turn into a real gas chamber. This can be prevented by choosing the most rational decision– forced-exhaust ventilation device with heat and moisture recovery.

What is heat recovery

Recovery means its preservation. The outgoing air flow changes the temperature (heats, cools) the supplied air by the supply and exhaust unit.

Scheme of operation of ventilation with heat recovery

The design assumes separation air flow to prevent them from mixing. However, when using a rotary heat exchanger, the possibility of the exhaust air flow entering the incoming air flow cannot be excluded.

The “Air Recuperator” itself is a device that provides heat recovery from exhaust gases. Heat exchange occurs through the dividing wall between the coolants, while the direction of movement of the air masses remains unchanged.

The most important characteristic of a recuperator is determined by the recuperation efficiency or efficiency. Its calculation is determined from the ratio of the maximum possible heat received and the actual heat received behind the heat exchanger.

The efficiency of recuperators can vary by wide range– from 36 to 95%. This indicator is determined by the type of recuperator used, the speed of air flow through the heat exchanger and the temperature difference between the exhaust and incoming air.

Types of recuperators and their advantages and disadvantages

There are 5 main types of air recuperators:

• Lamellar;
• Rotary;
• With intermediate coolant;
• Chamber;
• Heat pipes.

Lamellar

A plate recuperator is characterized by the presence of plastic or metal plates. Outgoing and incoming flows pass through different sides heat-conducting plates without contacting each other.

On average, the efficiency of such devices is 55-75%. Positive characteristic can be considered the absence of moving parts. The disadvantages include the formation of condensation, which often leads to freezing of the recuperative device.

There are plate heat exchangers with moisture-permeable plates that ensure the absence of condensation. The efficiency and principle of operation remain unchanged, the possibility of freezing of the heat exchanger is eliminated, but at the same time the possibility of using the device to reduce the level of humidity in the room is also excluded.

In a rotary recuperator, heat is transferred using a rotor that rotates between the supply and exhaust ducts. This device is characterized high level Efficiency (70-85%) and reduced energy consumption.

The disadvantages include slight mixing of flows and, as a result, the spread of odors, a large number of complex mechanics, which complicates the maintenance process. Rotary heat exchangers are effectively used for drying rooms, so they are an ideal option for installation in swimming pools.

Recuperators with intermediate coolant

In recuperators with an intermediate coolant, water or a water-glycol solution is responsible for heat transfer.

The exhaust air provides heating to the coolant, which, in turn, transfers heat to the incoming air flow. Air flows do not mix, the device is characterized by a relatively low efficiency (40-55%), usually used in industrial premises with a large area.

Chamber recuperators

A distinctive feature of chamber recuperators is the presence of a damper that divides the chamber into two parts. High efficiency (70-80%) is achieved due to the ability to change the direction of air flow by moving the damper.

Disadvantages include slight mixing of flows, transmission of odors and the presence of moving parts.

Heat pipes are a whole system of tubes filled with freon, which evaporates when the temperature rises. In another part of the tubes, the freon cools to form condensation.

The advantages include the elimination of mixing of flows and the absence of moving parts. Efficiency reaches 65-70%.

It should be noted that previously, due to their significant dimensions, recuperative units were used exclusively in production; now the construction market offers recuperators with small dimensions that can be successfully used even in small houses and apartments.

The main advantage of recuperators is the absence of the need for air ducts. However, this factor can also be considered as a disadvantage, since for effective operation a sufficient distance between the exhaust and supply air is required, otherwise fresh air is immediately drawn out of the room. The minimum permissible distance between opposite air flows should be at least 1.5-1.7 m.

Why is moisture recovery needed?

Moisture recovery is necessary to achieve a comfortable ratio of humidity and room temperature. A person feels best at a humidity level of 50-65%.

During the heating period, the already dry winter air loses even more moisture due to contact with the hot coolant, often the humidity level drops to 25-30%. With this indicator, a person not only feels discomfort, but also causes significant harm to his health.

In addition to the fact that dry air has Negative influence on a person’s well-being and health, it also causes irreparable damage to furniture and carpentry made of natural wood, as well as paintings and musical instruments. Some may say that dry air helps get rid of dampness and mold, but this is far from true. Such shortcomings can be overcome by insulating the walls and installing high-quality supply and exhaust ventilation while maintaining a comfortable level of humidity.

Ventilation with heat and moisture recovery: scheme, types, advantages and disadvantages

What is heat recovery ventilation? How this system works, what types there are and their pros and cons.

Ventilation with heat recovery

During the period of energy crisis and rising prices for energy resources, the use of energy-saving technologies in all areas of economic activity becomes especially relevant. The role of heat recuperators in this matter cannot be underestimated. Engineering installations not only significantly save gas for space heating, but also, practically free of charge, return heat intended for release into the atmosphere for useful use.

Operation of air exchange with air heating

Supply and exhaust ventilation with heat recovery solves three main problems:

• providing the premises with fresh air;
• return of thermal energy leaving with air through the ventilation system;
• preventing cold streams from entering the house.

The process can be schematically illustrated using an example. Organization of air exchange is necessary even on a frosty winter day with a temperature outside the window of -22°C. To do this, the supply and exhaust system is turned on and the fan is running, forcing air from the street. It seeps through the filter elements and, already cleaned, enters the heat exchanger.

As the air passes through it, it has time to warm up to +14-+15°C. This temperature may be considered sufficient, but not adequate sanitary standards for accommodation. To achieve room temperature parameters, it is necessary to bring the air to the required values ​​using the reheating function to +20°C in the recuperator itself using a heater (water, electric) of low power - 1 or 2 kW. With such temperature indicators, air enters the rooms.

The heater operates in automatic mode: when the outside air temperature drops, it turns on and operates until it heats up to the required values. At the same time, the waste stream is already heated to a “comfortable” 18 or 20 degrees. It is removed using a built-in ventilation unit, having previously passed through a heat exchange cassette. In it, it gives off heat to the oncoming cold air from the street, and only then goes into the atmosphere from the recuperator with a temperature of no more than 14-15°C.

Attention! Installation of metal-plastic structures violates natural flow fresh air flows into an apartment or house. The problem is solved by a forced system that supplies unheated air from the street, but also negates the energy saving efficiency of plastic windows. Supply and exhaust ventilation with a recuperator is a comprehensive solution to the heating problem with simultaneously functioning air exchange, an active method of energy conservation.

Advantages of a supply and exhaust system with heating function

• Supply fresh air, improve quality air environment indoors.
• Prevents the loss of moisture on the surface, the formation of condensation, mold and mildew.
• Eliminates the conditions for the appearance of viruses and bacteria in the room.
• Saves costs on electrical and thermal energy by recovering losses from waste streams of about 90% of heat.
• Promotes regular air exchange.
• The versatility of the design of heat exchange systems expands the scope of their application at various types of facilities.
• Economical use and maintenance. Maintenance, including cleaning, replacing filters, checking all components and components of the system, is carried out only once annually.

Attention! The operation of recuperators in old residential buildings, where natural air exchange is ensured by wooden window structures, cracks in wooden floors and leaks in doors, will be ineffective. The greatest effect from heat recovery is observed in modern buildings with high-quality insulation of rooms and good tightness.

Types of heat exchangers

The most common four categories of units are distinguished:

• Rotary type. Powered by mains power. Economical, but technically complex. The working element is a rotating rotor with metal foil applied over the entire surface. The heat exchanger with street air passing inside reacts to the temperature difference between the outside and inside the rooms. This adjusts the speed of its rotation. The intensity of heat supply changes, preventing icing of the recuperator in winter period, which allows you to avoid drying out the air. The efficiency of the devices is quite high and can reach 87%. In this case, it is possible to mix counter flows (up to 3% of total number) and the flow of odors and contaminants.
• Plate models. They are considered the most popular due to their affordable price and efficiency. It reaches 40-65% thanks to the aluminum heat exchanger. Due to the absence of rotating and friction-affected units and parts, they are considered simple in design and reliable in operation. Air flows separated by aluminum foil do not diffuse and pass on both sides of the heat-conducting elements. Variety: plate model with a plastic heat exchanger. Its efficiency is higher, but otherwise it has the same characteristics.

Attention! Plate devices are inferior to rotary devices in that they freeze and dry the air. Additional constant hydration is a must. The optimal area of ​​application is the wet environment of swimming pools.

• Recirculation type. Its “trick” is its complex design and the use of a liquid carrier (water, water-glycol solution or antifreeze) as an intermediate link in heat transfer. A heat exchanger is installed on the exhaust hose, which takes the heat from the exhaust air flow and heats the liquid with it. Another heat exchanger, but this time at the air intake from the street, transfers heat to the incoming air without mixing with it. The efficiency of such installations reaches 65%; they do not participate in moisture exchange. Electricity is required to operate.
• The roof type of devices is effective (58-68%), but for home use not suitable. It is used as a component in the ventilation of shops, workshops and other similar premises.

Calculation of the efficiency of the recuperator

You can roughly calculate how effective the installed supply ventilation with heat recovery will be, both in winter and summer, when the installation is working for cooling. The formula for calculating the temperature of the supply air flow for an installation depending on the numerical characteristic of energy efficiency (efficiency), external and indoor air temperatures looks like this:

Tpp = (tin – tul)*efficiency + tul,

where the temperature values ​​are:

Tpr – expected at the exit from the recuperator;

tin – indoors;

For calculations, the certified efficiency value of the device is taken.

As an example: at frosts of -25°C and room temperature +19°C, as well as an installation efficiency of 80% (0.8), the calculation shows that the required air parameters after passing through the heat exchanger will be:

Tpp = (19 – (-25))*0.8 – 25 = 10.2°С

The calculated temperature indicator of the air after the recuperator was obtained. In fact, taking into account the inevitable losses, this value will be within +8°C.

In the heat of +30°C in the yard and 22°C in the apartment, the air in a heat exchanger of the same efficiency is cooled to the design temperature before entering the room:

Tpp = tul + (tin – tul) * efficiency

Substituting the data, we get:

Tpp = 30 + (22-30)*0.8 = 23.6°C

Attention! The installation efficiency declared by the manufacturer and the actual one will differ. The correction value is affected by air humidity, the type of heat exchanger cassette, and the temperature difference between the outside and inside. If the recuperator is improperly installed and operated, the operating efficiency also decreases.

Modern energy-saving ventilation systems with the inclusion of recuperators are another step towards economical consumption of coolants. Moreover, temperature exchange settings are relevant in winter, but no less in demand in summer.

Supply and exhaust ventilation with heat recovery

How does supply and exhaust ventilation with heat recovery work? What are the advantages of supply and exhaust ventilation with a recuperator?

Supply and exhaust ventilation systems with heat recovery and recycling

Air recirculation in ventilation systems is the mixing of a certain amount of exhaust (exhaust) air into the supply air flow. Thanks to this, a reduction in energy costs for heating is achieved fresh air during the winter season.

Scheme of supply and exhaust ventilation with recovery and recirculation,

where L is air flow, T is temperature.

Heat recovery in ventilation- This is a method of transferring thermal energy from the exhaust air flow to the supply air flow. Recuperation is used when there is a temperature difference between the exhaust and supply air to increase the temperature of the fresh air. This process does not imply mixing of air flows; the process of heat transfer occurs through any material.

Temperature and air movement in the recuperator

Devices that perform heat recovery are called heat recuperators. They come in two types:

Heat exchangers-recuperators– they transmit heat flow through the wall. They are most often found in installations of supply and exhaust ventilation systems.

Regenerative heat exchangers– in the first cycle, which are heated by the exhaust air, in the second they are cooled, giving off heat to the supply air.

A supply and exhaust ventilation system with recovery is the most common way to use heat recovery. The main element of this system is the supply and exhaust unit, which includes a recuperator. Device air handling unit with a recuperator, it allows you to transfer up to 80-90% of the heat to the heated air, which significantly reduces the power of the heater in which the supply air is heated, in case of insufficient heat flow from the recuperator.

Features of the use of recirculation and recovery

The main difference between recovery and recirculation is the absence of mixing air from indoors to outdoors. Heat recovery is applicable in most cases, while recirculation has a number of limitations that are specified in regulatory documents.

SNiP 41-01-2003 does not allow re-supply of air (recirculation) in the following situations:

• In rooms where the air flow is determined based on the harmful substances emitted;
• In rooms where there are pathogenic bacteria and fungi in high concentrations;
• In rooms with the presence of harmful substances that sublime upon contact with heated surfaces;
• In premises of categories B and A;
• In premises where work is carried out with harmful or flammable gases and vapors;
• In premises of category B1-B2, in which flammable dust and aerosols may be released;
• From systems with local suction of harmful substances and explosive mixtures with air;
• From airlock vestibules.

Recirculation in supply and exhaust units is actively used more often with high system productivity, when air exchange can be from 1000-1500 m 3 / h to 10,000-15,000 m 3 / h. The removed air carries a large supply of thermal energy; mixing it with the external flow allows you to increase the temperature of the supply air, thereby reducing the required power of the heating element. But in such cases, before being re-entered into the room, the air must pass through a filtration system.

Ventilation with recirculation allows you to increase energy efficiency and solve the problem of energy saving in the case when 70-80% of the removed air is re-entered into the ventilation system.

Air handling units with recovery can be installed at almost any air flow rate (from 200 m 3 /h to several thousand m 3 / h), both small and large. Recuperation also allows heat to be transferred from the exhaust air to the supply air, thereby reducing the energy demand on the heating element.

Relatively small installations are used in ventilation systems of apartments and cottages. In practice, air handling units are installed under the ceiling (for example, between the ceiling and the suspended ceiling). This solution requires some specific installation requirements, namely: small overall dimensions, low noise level, simple maintenance.

A supply and exhaust unit with recovery requires maintenance, which requires making a hatch in the ceiling for servicing the recuperator, filters, and blowers (fans).

Main elements of air handling units

A supply and exhaust unit with recovery or recirculation, which has both the first and second processes in its arsenal, is always a complex organism that requires highly organized management. The air handling unit hides behind its protective box such main components as:

• Two fans of various types, which determine the performance of the installation in terms of flow.
• Heat exchanger recuperator– heats the supply air by transferring heat from the exhaust air.
• Electric heater– heats the supply air to the required parameters in case of insufficient heat flow from the exhaust air.
• Air filter– thanks to it, the outside air is monitored and cleaned, as well as the exhaust air processed before the recuperator to protect the heat exchanger.
• Air valves with electric drives - can be installed in front of the outlet air ducts for additional regulation of the air flow and blocking the channel when the equipment is turned off.
• Bypass– thanks to which the air flow can be directed past the recuperator in the warm season, thereby not heating the supply air, but supplying it directly to the room.
• Recirculation chamber– ensuring the admixture of exhaust air into the supply air, thereby ensuring recirculation of the air flow.

In addition to the main components of the air handling unit, it also includes a large number of small components, such as sensors, an automation system for control and protection, etc.

Ventilation with recovery, recirculation

Design, calculation, requirements for ventilation with recovery, recirculation. Free consultation.

Features of the ventilation system with heat recovery, its operating principle

The heat recuperator often becomes part of the ventilation system. However, not many people know what this device is and what features it has. Another important question is whether the purchase of a recuperator will pay off, how it will change the operation of the ventilation system, and whether it is possible to create a similar element with your own hands. We will answer these and many other questions in the information below.

How the system works

An unusual name was given to an ordinary heat exchanger. The purpose of the device is to remove part of the heat from the already exhausted air from the room. The selected heat is transferred to the flow that comes from the supply system clean air. The above information determines what the purpose of use similar system– savings on heating the house. The following points should be noted:

1. In summer, the system allows you to reduce air conditioning costs.
2. The device in question can work in both directions, that is, it takes away heat in the supply and exhaust systems.

Operating principle of a heat recovery system

The above information determines that a heat recuperator is installed in many ventilation systems. It is not active, many versions do not consume energy, do not make noise, and have an average efficiency rating. Heat exchangers have been installed over the years, but in Lately Many people wonder if there are reasons to complicate the ventilation system with this device, which has quite a lot of problems due to working in an environment with different temperatures.

System installation problems

There are practically no potential problems associated with the use of such equipment. Some are resolved by the manufacturer, others become a headache for the buyer. The main problems include:

• Formation of condensation. The laws of physics determine that when air passes through high temperature condensation occurs through a cold closed environment. If the ambient temperature is below zero, the ribs will begin to freeze. All information provided in this paragraph determines a significant decrease in the efficiency of the device.
• Energy efficiency. All ventilation systems operating in conjunction with a recuperator are energy dependent. The economic calculation carried out determines that only those models of recuperators that will save more energy than they spend will be useful.
• Payback period. As previously noted, the device is designed to save energy. An important determining factor is how many years it takes for the purchase and installation of recuperators to pay off. If the indicator in question exceeds 10 years, then there is no point in installing it, since during this time other elements of the system will require replacement. If calculations show that the payback period is 20 years, then installing the device should not be considered.

The appearance of condensation on the vent. system

The above problems should be taken into account when choosing a heat exchanger, of which there are several dozen types.

Device options

Sidebar: Important: There are several heat exchanger options. When considering the operating principle of the device, it should be borne in mind that it depends on the type of device itself. The plate type of device is a device in which the supply and exhaust ducts pass through a common housing. The two channels are separated by partitions. The partition consists of a large number of plates, which are often made of copper or aluminum. It is important to note that the copper composition has greater thermal conductivity than aluminum. However, aluminum is cheaper.

The features of the device in question include the following:

1. Heat is transferred from one channel to another using heat-conducting plates.
2. The principle of heat transfer determines that the problem of condensation appears immediately after the heat exchanger is connected to the system.
3. In order to eliminate the possibility of condensation, a thermal-type icing sensor is installed. When a signal appears from the sensor, the relay opens a special valve - the bypass.
4. When the valve opens, cold air enters two channels.

This class of device can be classified as a low price category. This is due to the fact that when creating the structure, a primitive method of heat transfer is used. The effectiveness of this method is lower. An important point is that the cost of the device depends on its size and the size of the supply system itself. An example is the channel size of 400 by 200 millimeters and 600 by 300 millimeters. The difference in price will be more than 10,000 rubles.

Ventilation scheme with recovery

The structure consists of the following elements:

• Two inlet air ducts: one for fresh air, the second for exhaust air.
• From a coarse filter for supplied air from the street.
• Directly the heat exchanger itself, which is located in the central part.
• Damper, which is necessary to supply air in case of icing.
• Condensate drain valve.
• A fan that is responsible for pumping air into the system.
• Two channels with reverse side designs.

The dimensions of the heat exchanger depend on the power of the ventilation system and the size of the air ducts.

The next type of design is a device with heat pipes. Its device is almost identical to the previous one. The only difference is that the design does not have a huge number of plates that penetrate the partition between the channels. For this, a heat pipe is used - special device which transfers heat. The advantage of the system is that freon evaporates at the warmer end of the sealed copper tube. Condensation accumulates at the cooler end. The features of the design under consideration include:

The operation of the system has the following features:

• The system contains a working fluid that absorbs thermal energy.
• Steam travels from a warmer point to a colder point.
• The laws of physics determine that steam condenses back into liquid and gives off the retained temperature.
• Along the wick, the water flows back to the warm point, where it forms steam again.

The design is sealed and works with high efficiency. The advantage is that the design is smaller and easier to operate.

The rotary type can be called a modern version. At the border between the supply and exhaust channels there is a device that has blades - they rotate slowly. The device is designed in such a way that the plates are heated on one side and transferred from the other by rotation. This is because the blades are positioned at a specific angle to redirect the heat. The features of the rotor system include the following:

• Quite high efficiency. As a rule, plate and tubular systems have an efficiency of no more than 50%. This is due to the fact that they do not have active elements. By redirecting the air flow, the efficiency of the system can be increased to 70-75%.
• The rotation of the blades also determines the solution to the problem of condensation on the surface. The problem with low humidity during the cold season is also solved.

However, several disadvantages can also be identified:

• As a rule, the more complex the system, the less reliable it is. The rotor system has a rotating element that can fail.
• If there is high humidity in the room, then using the structure is not recommended.

It is also important to understand that the recuperator chambers do not have a hermetically sealed separation. This moment determines the transfer of odor from one chamber to another. In general, the rotor system resembles a kind of fan of quite large overall dimensions with bulky blades. To improve system performance, the device must be connected to a power source.

The intermediate type coolant is a classic design that consists of water heating with convectors and pumps. The system is used extremely rarely, due to low efficiency and design complexity. However, it is practically irreplaceable in the case where the supply and exhaust ducts are located at a great distance from each other. Heat is transferred through water, which has been used for many years to create such systems. To ensure water circulation, regardless of the location of devices in the system, a pump is installed. It is important to understand that the design features in this case determine the low reliability of the system and the need for periodic inspections.

Features of the ventilation system with heat recovery, its operating principle

Ventilation with heat recovery provides a comfortable and healthy microclimate in the house and heat retention. Determination of effectiveness and implementation options.

Supply and exhaust ventilation with heat recovery: principle of operation, review of advantages and disadvantages

Fresh air supply to cold period time leads to the need to heat it to ensure the correct indoor microclimate. To minimize energy costs, supply and exhaust ventilation with heat recovery can be used.

Understanding the principles of its operation will allow you to most effectively reduce heat loss while maintaining a sufficient volume of replaced air.

Energy saving in ventilation systems

In the autumn-spring period, when ventilating rooms, a serious problem is the large temperature difference between the incoming air and the air inside. The cold stream rushes down and creates an unfavorable microclimate in residential buildings, offices and production, or an unacceptable vertical temperature gradient in a warehouse.

A common solution to the problem is to integrate a heater into the supply ventilation, with the help of which the flow is heated. Such a system requires energy consumption, while a significant volume of warm air escaping outside leads to significant heat loss.

If the air inlet and outlet channels are located nearby, then it is possible to partially transfer the heat of the outgoing flow to the incoming one. This will reduce the energy consumption of the heater or eliminate it altogether. A device for ensuring heat exchange between gas flows of different temperatures is called a recuperator.

During the warm season, when the outside air temperature is significantly higher than room temperature, a recuperator can be used to cool the incoming flow.

Design of a unit with a recuperator

The internal structure of supply and exhaust ventilation systems with an integrated recuperator is quite simple, so it is possible to independently purchase and install them element by element. If assembly or self-installation is difficult, you can purchase ready-made solutions in the form of standard monoblock or individual prefabricated structures to order.

Main elements and their parameters

The body with heat and noise insulation is usually made of sheet steel. When wall installation it must withstand the pressure that occurs when foaming the cracks around the unit, and also prevent vibration from the operation of fans.

In the case of distributed air intake and air flow through various rooms An air duct system is connected to the housing. It is equipped with valves and dampers to distribute flows.

If there are no air ducts, a grille or diffuser is installed on the supply opening on the side of the room to distribute the air flow. An external type air intake grille is installed on the inlet opening on the street side to prevent birds, large insects and debris from entering the ventilation system.

Air movement is provided by two fans of axial or centrifugal action. In the presence of a recuperator, natural air circulation in a sufficient volume is impossible due to the aerodynamic resistance created by this unit.

The presence of a recuperator involves the installation of fine filters at the inlet of both flows. This is necessary to reduce the intensity of clogging of thin heat exchanger channels with dust and grease deposits. Otherwise, for the system to function fully, it will be necessary to increase the frequency of preventive maintenance.

One or more recuperators occupy the main volume of the supply and exhaust device. They are mounted in the center of the structure.

In the case of severe frosts typical for the territory and insufficient efficiency of the recuperator to heat the outside air, you can additionally install a heater. Also, if necessary, a humidifier, ionizer and other devices are installed to create a favorable microclimate in the room.

Modern models include an electronic control unit. Complex modifications have functions for programming operating modes depending on the physical parameters of the air environment. External panels have an attractive appearance, thanks to which they can fit well into any interior.

Solving the problem of condensation

Cooling the air coming from the room creates the prerequisites for the release of moisture and the formation of condensation. In the case of a high flow rate, most of it does not have time to accumulate in the recuperator and goes outside. With slow air movement, a significant part of the water remains inside the device. Therefore, it is necessary to ensure that moisture is collected and removed outside the housing of the supply and exhaust system.

Moisture is removed into a closed container. It is placed only indoors to avoid freezing of the outflow channels when sub-zero temperatures. There is no algorithm for reliable calculation of the volume of water received when using systems with a recuperator, so it is determined experimentally.

Reusing condensate for air humidification is undesirable, since water absorbs many pollutants such as human sweat, odors, etc.

You can significantly reduce the volume of condensate and avoid problems associated with its occurrence by organizing a separate exhaust system from the bathroom and kitchen. It is in these rooms that the air has the highest humidity. If there are several exhaust systems, the air exchange between the technical and residential areas must be limited by installing check valves.

If the exhaust air flow is cooled to negative temperatures inside the recuperator, condensate turns into ice, which causes a reduction in the open cross-section of the flow and, as a consequence, a decrease in volume or a complete cessation of ventilation.

For periodic or one-time defrosting of the recuperator, a bypass is installed - a bypass channel for the movement of supply air. When a flow bypasses the device, heat transfer stops, the heat exchanger heats up and the ice passes into a liquid state. The water flows into the condensate collection tank or evaporates outside.

When the flow passes through the bypass, there is no heating of the supply air through the recuperator. Therefore, when activating this mode, it is necessary automatic switching on heater.

Features of various types of recuperators

There are several structurally different options for implementing heat exchange between cold and heated air flows. Each of them has its own distinctive features, which determine the main purpose for each type of recuperator.

Plate cross-flow recuperator

The design of the plate recuperator is based on thin-walled panels, connected alternately in such a way as to alternate the passage of flows of different temperatures between them at an angle of 90 degrees. One of the modifications of this model is a device with finned channels for air passage. It has a higher heat transfer coefficient.

Heat exchange panels can be made of various materials:

• copper, brass and aluminum-based alloys have good thermal conductivity and are not susceptible to rust;
• plastic made from a hydrophobic polymer material with a high thermal conductivity coefficient and low weight;
• hygroscopic cellulose allows condensation to penetrate through the plate and back into the room.

The disadvantage is the possibility of condensation forming at low temperatures. Due to the small distance between the plates, moisture or ice significantly increases aerodynamic drag. In case of freezing, it is necessary to block the incoming air flow to warm the plates.

The advantages of plate recuperators are as follows:

• low cost;
• long service life;
• long period between preventive maintenance and the ease of its implementation;
• small dimensions and weight.

This type of recuperator is most common for residential and office premises. It is also used in some technological processes, for example, to optimize fuel combustion during the operation of furnaces.

Drum or rotary type

The operating principle of a rotary recuperator is based on the rotation of a heat exchanger, inside of which there are layers of corrugated metal with high heat capacity. As a result of interaction with the outgoing flow, the drum sector is heated, which subsequently gives off heat to the incoming air.

The advantages of rotary recuperators are as follows:

• quite high efficiency compared to competing types;
• return of a large amount of moisture, which remains in the form of condensation on the drum and evaporates upon contact with incoming dry air.

This type of recuperator is less often used for residential buildings for apartment or cottage ventilation. It is often used in large boiler houses to return heat to furnaces or for large industrial or commercial premises.

However, this type of device has significant disadvantages:

• a relatively complex design with moving parts, including an electric motor, drum and belt drive, which requires constant maintenance;
• increased noise level.

Sometimes for devices of this type you can come across the term “regenerative heat exchanger”, which is more correct than “recuperator”. The fact is that a small part of the exhaust air gets back due to the loose fit of the drum to the body of the structure.

This imposes additional restrictions on the ability to use devices of this type. For example, polluted air from heating stoves cannot be used as a coolant.

Tube and casing system

A tubular type recuperator consists of a system of thin-walled tubes of small diameter located in an insulated casing, through which there is an influx of outside air. The casing removes warm air from the room, which heats the incoming flow.

The main advantages of tubular recuperators are as follows:

• high efficiency due to the countercurrent principle of movement of the coolant and incoming air;
• simplicity of design and absence of moving parts ensures low noise levels and rarely requires maintenance;
• long service life;
• the smallest cross-section among all types of recovery devices.

Tubes for this type of device use either light-alloy metal or, less commonly, polymer. These materials are not hygroscopic, therefore, with a significant difference in flow temperatures, intense condensation may form in the casing, which requires constructive solution on its removal. Another disadvantage is that the metal filling has significant weight, despite its small dimensions.

The simplicity of the design of a tubular recuperator makes this type of device popular for self-production. Plastic pipes for air ducts, insulated with a polyurethane foam shell, are usually used as an external casing.

Device with intermediate coolant

Sometimes the supply and exhaust air ducts are located at some distance from each other. This situation may arise due to technological features building or sanitary requirements for reliable separation of air flows.

In this case, an intermediate coolant is used, circulating between the air ducts through an insulated pipeline. Water or a water-glycol solution is used as a medium for transferring thermal energy, the circulation of which is ensured by the operation of a pump.

If it is possible to use another type of recuperator, then it is better not to use a system with an intermediate coolant, since it has the following significant disadvantages:

• low efficiency compared to other types of devices, therefore such devices are not used for small rooms with low air flow;
• significant volume and weight of the entire system;
• the need for an additional electric pump to circulate the liquid;
• increased noise from the pump.

There is a modification of this system when, instead of forced circulation The heat exchange fluid uses a medium with a low boiling point, such as freon. In this case, movement along the contour is possible naturally, but only if the supply air duct is located above the exhaust air duct.

Such a system does not require additional energy costs, but only works for heating when there is a significant temperature difference. In addition, it is necessary to fine-tune the point at which the state of aggregation of the heat exchange fluid changes, which can be achieved by creating the required pressure or a certain chemical composition.

Main technical parameters

Knowing the required performance of the ventilation system and the heat exchange efficiency of the recuperator, it is easy to calculate savings on air heating for a room under specific climatic conditions. By comparing the potential benefits with the costs of purchasing and maintaining the system, you can reasonably make a choice in favor of a recuperator or a standard air heater.

Efficiency

The efficiency of a recuperator is understood as the efficiency of heat transfer, which is calculated using the following formula:

• T p – temperature of the air entering the room;
• Tn – outside air temperature;
• T in – room air temperature.

The maximum efficiency value at a standard air flow rate and a certain temperature regime is indicated in the technical documentation of the device. Its actual figure will be slightly less. In the case of self-manufacturing of a plate or tubular recuperator, in order to achieve maximum heat transfer efficiency, you must adhere to the following rules:

• The best heat transfer is provided by counter-flow devices, then cross-flow devices, and the least by unidirectional movement of both flows.
• The intensity of heat transfer depends on the material and thickness of the walls separating the flows, as well as on the duration of the air inside the device.

where P (m 3 / hour) – air flow.

The cost of recuperators with high efficiency is quite high; they have a complex design and significant dimensions. Sometimes you can get around these problems by installing a few more simple devices so that the incoming air passes through them successively.

Performance ventilation system

The volume of air passed through is determined by static pressure, which depends on the power of the fan and the main components that create aerodynamic resistance. As a rule, its exact calculation is impossible due to the complexity mathematical model Therefore, experimental studies are carried out for standard monoblock structures, and components are selected for individual devices.

The fan power must be selected taking into account the throughput of installed heat exchangers of any type, which is indicated in the technical documentation as the recommended flow rate or volume of air passed by the device per unit of time. As a rule, the permissible air speed inside the device does not exceed 2 m/s.

Otherwise, at high speeds in the narrow elements of the recuperator, a sharp increase aerodynamic resistance. It leads to unnecessary costs electricity, ineffective heating of outside air and reduced service life of fans.

Changing the direction of air flow creates additional aerodynamic drag. Therefore, when modeling the geometry of an indoor air duct, it is desirable to minimize the number of pipe turns by 90 degrees. Air diffusers also increase resistance, so it is advisable not to use elements with complex patterns.

Dirty filters and grilles create significant interference with flow, so they must be periodically cleaned or replaced. One effective way to assess clogging is to install sensors that monitor the pressure drop in areas before and after the filter.

Operating principle of rotary and plate recuperator:

Measuring the efficiency of a plate-type recuperator:

Household and industrial systems ventilation systems with an integrated recuperator have proven their energy efficiency in retaining heat indoors. Now there are many offers for the sale and installation of such devices, both in the form of ready-made and tested models, and on individual orders. You can calculate the necessary parameters and perform installation yourself.

Supply and exhaust ventilation with heat recovery: design and operation

Supply and exhaust ventilation device with heat recovery. Types of recuperators, their advantages and disadvantages. Calculation of efficiency and nuances of ensuring the required performance.

It is impossible to create a comfortable indoor microclimate without a good ventilation system. Plastic windows, doors and finishing materials make the house so airtight that it can lead to a lack of natural ventilation, dampness and condensation. And if you take into account the general air pollution, then you simply cannot do without effective air filters. Such houses must have an air recovery system for private houses. This device is driven by an air handling unit, which contains a recuperator. Such a device will not only provide your home with fresh, purified air, but will also help reduce heating costs.

Recuperator for a private house. Advantages

The term "recuperator" is translated from Latin. means returning. The device itself is a heat exchanger that retains the heat of the room and transfers it to the air entering from the street. Recuperation is a ventilation method with minimum consumption heat. This device helps to retain up to 70% of the heat and return it back to the room.

Main advantages:

• Low noise level
• No need to open windows
• Possibility of installation in a suspended ceiling structure
• Saving heating and air conditioning costs
• Convenience and availability of additional functions

Automatic adjustment of air flow intensity makes the use of devices not only safe, but also comfortable.

How to choose a ventilation recuperator?

All modern ventilation units use the same operating principle - they provide air flow into the house, cleaning it from dust and impurities. Such systems may differ in size, cleaning class, performance, configuration and the presence of additional functions.

Units with an electric heat exchanger have a built-in rotary heat exchanger with an efficiency of 80% and a remote control. In devices with a water heater, it is possible to control the speed and temperature of the incoming air flow. Such ventilation units are more popular than those with electric heat exchangers.

Considering the minimal energy consumption of a recuperator for a private home, the price of which is quite affordable, the cost of installing a ventilation system will pay off very quickly. And if we also take into account the undoubted benefits for health and general well-being, then the choice in favor of a PVU with a recuperator becomes obvious.

Modern technologies that have come to our country encourage the population to also use the latest developments. Solar panels, room temperature controllers and other smart devices can not only reduce your bills utilities, but also maintain a comfortable temperature in the room. Of course, a recuperator for a private home cannot be called an innovation, however, the savings Money and heat energy is evident.

This device is a design similar to a house ventilation system. Their difference lies in the fact that conventional ventilation removes stale air from the room and fills it with fresh air. The recuperator performs similar actions, only it brings heated warm or cooled air into the house. An air conditioner performs similar functions, however, it requires electricity and a refrigerant - freon; the heat recovery unit does without it. Heating or cooling of the inflow occurs due to the heat exchange of the primary and secondary coolant through the wall separating the air masses.

The main link of the air handling unit with a recuperator is the heat exchanger. The device is equipped with a thermal electric heater or fan, check valves to prevent air movement in the opposite direction, and much more.

The use of such a system makes it possible to recover part of the thermal energy that is usually lost when passing through ventilation ducts. Warm air masses circulate freely in the heat exchanger, come into contact with the cold flow through the dividing wall and transfer their thermal energy to the latter.

A surface-type recuperator is a heat exchanger with double walls. One channel is occupied by the outgoing primary, the other by the secondary, cooler one. The walls have high thermal conductivity and are installed to prevent mixing of air flows of different temperatures. The outgoing air element passes along the box, the incoming air element crosses. As a result of heat transfer to cold air, heated air masses enter the house.

The temperature of the incoming air depends on the temperature of the outgoing air. The warmer the outgoing stream, the higher the supply temperature.

Operating principle

The principle of operation of the recuperator is that it accumulates heat from the removed flow and communicates it with high efficiency to the air supply masses. This allows you to save money and supply a fresh heated air element into the house.

The operating principle of the system is determined by two principles:

1. Waste or stale air masses are removed from the room, pass through the ceramic recovery chamber and heat it. In this case, almost 97% of the thermal energy is released. When the recovery chamber heats up, the heat exchanger automatically switches to the fresh jet inflow mode.
2. The air passes through the ceramic recovery chamber, is heated by the heat accumulated in it and is supplied to the house. Cooling of the regenerator serves as a signal to turn on the fan in exhaust mode.

Such a ventilation system with a recuperator allows you to reduce the consumption of gaseous, solid or liquid fuel, which may be necessary for the operation of other devices, and create comfortable living conditions.

Note! Installing a supply and exhaust air recuperator for your home will save up to 80% of the heat in the room.

Advantages of a thermal power device

A thermal power device of this type has been gaining great popularity recently. There is no need to ventilate the home in summer and winter, thereby releasing precious heat outside. On a dusty summer day, the device will supply the room with clean atmospheric air, which will first pass through an air purification filter.

There is also no need to use the mentioned system manually - the automation will do it for you. Cold masses in winter will be heated due to the outgoing warm flow, and hot summer days will cool down when heat is transferred to a cooler flow.

In addition, the system is characterized by the following number of advantages:

• saving money on heating;
• savings on separate exhaust fans;
• removal of unpleasant heavy odors;
• removal of dust particles;
• ease of operation and installation;
• low cost of use;

• process automation;
• long service life of the system.

Even periodic use of a heating installation will allow you to saturate your home with clean atmospheric air masses without losing heat or, conversely, increasing the temperature.

High-quality ventilation

Installing a recuperator will keep the house clean along with the flow of fresh outside air. Tobacco, fireplace or smoke of other origins, carbon dioxide or other unhealthy emissions, harmful or unpleasant odors - a rotary heat exchanger can handle everything. The operation of the system has a beneficial effect on the human body, drying air with high humidity, which is especially important for hypertensive patients, as well as people with atherosclerosis or cardiovascular diseases. In addition, high humidity threatens other ailments.

Economical heating

By installing a heat exchanger, you will ensure stable savings not only in money, but also in the heat in the house. The outgoing warm flow will warm up the cold supply air to comfortable temperature, which will significantly avoid extra work heating equipment. The heating system carefully handles the heat entering its box, practically preventing it from escaping into the atmosphere. There is also no need to monitor the temperature of the incoming air masses; this will be done by the heat exchanger, supplying them with only a small temperature difference compared to the outgoing flow.

Important! According to experts, savings in electricity or any type of fuel for heating devices range from 40 to 50%. Of course, you should not neglect the high-quality thermal insulation of the room.

No additional ventilation

Gas stoves, fireplaces, water heaters and crying metal-plastic windows require additional ventilation or periodic ventilation. Frosty and hot periods of the year significantly complicate this process: the first threatens to cool the room, the second threatens with dust and hot dry winds with low humidity. If you decide to buy an air recuperator, you will ensure high-quality ventilation of the entire house, avoiding unnecessary financial expenses and installation of equipment for additional ventilation.

Silent and high-quality air purification

In any case, the atmospheric supply air brings with it dust particles, dirt elements, diluted vehicle exhaust gases, chimneys and industrial enterprises. An air filter installed in a heat-energy device will rid the house of unwanted odors and dust particles. After undergoing high-quality cleaning, the atmospheric stream will fill the room with not only fresh, but also clean air. True, the latter will be determined by the necessary regular maintenance of the air filter and other elements of the system.

Note! A filter clogged with dust or uncleaned is a breeding ground for pathogenic bacteria. Its regular cleaning and periodic replacement will allow the home owner to avoid infectious respiratory diseases.

Recyclers for an apartment or house have high operating efficiency and low noise levels, which range from 25-35 dB. This is equivalent to the sound made by an air conditioner.

Recuperator for a private home: types and characteristics

Supply and exhaust recuperators can have various design features. Pick up suitable option A sales consultant in any specialized store of heating devices will help.

The following types of equipment exist:

• lamellar;
• rotary;
• roof;
• recirculating water.

All of them are designed to create a favorable indoor climate, be it an apartment, a large mansion or a country house.

Related article:

Types and features of devices, additional functions. Power calculation based on room parameters. Care tips.

Lamellar

It is the most common type due to its good performance, ease of operation and low price. This type of recuperator consists of fixed metal plates with a large specific heat capacity and relatively light weight. The plates are collected in a kind of cassette, which slightly resembles a beehive. Atmospheric air passes through the apparatus box with cassettes and is then heated or cooled, depending on the winter or summer season. The condensate formed during operation is discharged through a specially available drainage outlet or channel.

Along with the listed advantages, the system has a certain disadvantage: the formation of ice in the box, which is especially evident in the autumn-winter period.

Rotary

A recuperator of this type carries out the inflow and outflow of the air stream due to the blades. The thermal power system has from one to two drive rotors, depending on the model. Externally, the installation looks like a cylindrical barrel with a drum. As air is pumped out of the room and the cylindrical box is heated, atmospheric mass is taken in.

Advantages of this device:

• improved efficiency;
• increased efficiency;
• absence of condensate, and, consequently, drainage gutters;
• absence of ice;

• does not dry out the air, which does not require additional humidification;
• adjusting the amount of air supply and intake due to the speed of rotation of the blades.

However, there are also disadvantages:

• increased electricity consumption;
• rotating elements wear out faster than stationary ones;
• the need for additional exhaust to prevent possible mixing of incoming and outgoing air masses.

Note! Before purchasing a rotary recuperator, you need to take it into account increased power, which can lead to increased cross-section of the electrical wiring of the room.

Roof

This recuperator processes large masses of air. The feasibility of its use can be explained by a large mansion, other residential or non-residential premises. The principle of operation is in many ways similar to the plate unit, however, the latter differs from the roof unit in its smaller size. The ease of installation of the device, low cost of maintenance and operation made it indispensable in ventilation devices shops, repair shops, production areas. Installing such a recuperator on the roof generally eliminates the penetration of any sounds or noise into the room.

Glycol recuperator

The glycol (or recirculation) regenerative apparatus combines the qualities of plate and rotary thermal devices. Its main difference from the previous ones is the use of an intermediate coolant. The last is a water-glycol solution consisting of propylene glycol or ethylene diluted with distilled water. The mixture has a high heat capacity, which allows it to utilize a large amount of heat, and retains its working qualities at sub-zero temperatures. In severe low-temperature conditions, it is possible to replace the specified coolant with antifreeze. The equipment allows you to work simultaneously with several ventilation ducts, sleeves or hoods.

Recuperator for an apartment: calculation and review of manufacturers

An apartment heat and power device will be the best purchase, especially if the home is located in a big city or the center of a metropolis. Automotive and industrial gases, street noise, heat or cold will forever remain outside the room. The device will not only add a lot of clean air to the apartment, but will also allow you to save on heating, ventilation and cleaning the incoming atmospheric flow. This is achieved by simple heat exchange between the supply and exhaust flows passing through a heat-insulating box with a cleaning filter.

Recuperator calculation

You can calculate the required heat and power device yourself, without resorting to the services of specialized companies. Calculation of the efficiency and efficiency of the device is determined by knowledge of the energy costs for the supply or exhaust masses. The calculation formula is:

Q = 0.335 x L x (t 1 – t 2),

where L is the flow of air masses, t 1 is the temperature of the inflow, t 2 is the temperature of the outgoing masses, 0.335 is the regional coefficient.

The efficiency is calculated using the following formula:

E = Q x n,

where: Q – energy or electrical costs for heating or cooling the jet, n – device efficiency.

Helpful advice! Before buying a recuperator for a private house or city apartment, you need to familiarize yourself with their types, technical characteristics and the operating principle. It may be necessary to carry out preparatory installation work and draw up a project.

Recuperator PRANA

This manufacturer of heat power and ventilation equipment has been on the market for more than 15 years. Its equipment has a long service life, high efficiency and reasonable prices.

Operating characteristics of the device:

• type – lamellar;
• electricity consumption – 5-90 V/hour, depending on the model;
• noise level – 25-140 dB;
• unit length – 500 mm;
• incoming jet – 115-650 m³/h;
• outgoing jet – 105-610 m³/h;
• Efficiency – 79-80%, depending on the model.

The entire model range is completed remote control controls, operates at ambient temperatures from -15 to 45°C. The relatively low price of the air recuperator, significant retention of the set temperature during heating or heating, and small dimensions make this device one of the most popular, as confirmed by numerous positive reviews. The Prana recuperator can be built into the wall of a room or installed outdoors. Installation of the device is quite easy and is carried out within 2-3 hours.

Notice similar decentralized system only possible by the presence of a ventilation grille on the wall. Not the least positive quality is heat exchangers made of copper, which has an antimicrobial effect. average price an air recuperator for a home of this brand is about 25,000 rubles. The cost of devices with increased productivity ranges from 50 to 110 thousand rubles.

Recuperators MARLEY

The compact German heat exchanger is equipped with a ceramic heat exchange element, which allows the device to be operated even at a temperature of -30ºC. Washing it and cleaning the air filters is a simple operation that can be carried out by the average user. The duration of continuous operation is about 6 months, after this period the indicator light will light up. Operating the device near highways or in the central part of the city will force more frequent cleaning. This operation does not take much time and lasts 15-20 minutes.

You can buy an air recuperator for your home, the price of which is 24,000 rubles, in a specialized store. At a fairly moderate cost, the device has the following performance characteristics:

1. three power phases – 15, 25 and 40 m³/h;
2. electrical power consumption – from 3.5 to 8 W;
3. The electric motor rotor is brushless;
4. noise level – 22, 29 and 35 dB;
5. heat recovery – 80-85%;
6. service area – from 60 m²;
7. external dimensions – 285-500 mm. The small dimensions of the unit allow it to be installed in the wall.

A new line from the manufacturer Marley is the menv 180 recuperator, which differs from previous analogues in its low power consumption - only 3 W. Nice functional additions are:

• temperature, carbon dioxide and humidity controllers;
• improved aerodynamics;
• low noise level;
• waterproofing coating for work in damp residential or non-residential premises;
• high category of supply jet cleaning.

By installing such a recuperator, the price of which is around 27,500 rubles, you will forget about street soot and exhaust gases, dust, fog and emissions from industrial enterprises.

DIY recuperator

Any craftsman can make an air recuperator for the home with his own hands. For this you will need:

• two sheets of galvanized steel;
• wood-laminated box for the shell of the apparatus;
• cork gaskets;
• silicone neutral sealant;
• pressure controller;
• metal corners;
• thermal insulating mineral wool.

An electric jigsaw, metal fasteners and connecting flanges will also be useful for the work.

Steel sheets must be cut into rectangular plates measuring 200x300 mm. To do this you will need about 3–4 m² of steel. Cutting must be done very carefully so that the sections do not have burrs or nicks. For this purpose, it is recommended to use a special tool - a grinder or a hacksaw.

Then the plates are stacked on top of each other with a gap of at least 4 mm. This distance is ensured by gluing along the perimeter of each element of thermal insulation material (cork, wood or textolite). After laying the plates, the joints are treated with a special neutral sealant.

The housing is then fabricated and sized to fit inside its plate structure. Holes are cut in the walls of the housing into which pre-prepared plastic flanges are inserted, which must correspond to the diameter of the air ducts. All joints are also carefully sealed.

When the sealant has dried, the plate structure is placed inside the housing. External walls must be lined thermal insulation material, for example, polystyrene foam or glass wool. Ready design, in order to enhance the aesthetic component, can be placed in a wooden box.

Note! Visually noticeable crevices and slits in the box of a self-assembled recuperator for a private home must be filled with silicone neutral hermetic mass.

Previously, recuperators and ventilation systems were installed only in industrial production, coal and mining mines. Today, heating devices for exhaust gas recovery are increasingly located in houses and apartments.

An industrial device or a self-assembled air recuperator becomes ours an indispensable assistant. It serves clean chilled or warmed atmospheric air, cleans the house of dust and unpleasant odors and saves some money on heating the room.