The word "recovery" comes from the Latin word "recuperation", which means returning, receiving. In a broad sense, this term needs to be understood: in each technological process, materials or energy is consumed. Recuperation allows you to return a part of the energy for use in the same process.
Recovery air is the process of heat selection from the air removed and the power transmission of the air is injected. Technologically, the recovery process is carried out using air conditioners with a recovery containing complex or supply-exhaust ventilation systems. The heat exchanger is designed to ensure that the incoming and outgoing air flows are not mixed with each other, but only exchanged thermal energy. It is clear that using the air recovery systems, the air located in the room can not only be heated, but also cool - it all depends on the direction of the thermal process. At the same time, the heat of incoming air should not be given, but on the contrary, to take it. An important characteristic of the recovery system is the so-called efficiency coefficient, which is mathematically expressed by the ratio of the actual amount of heat to the maximum possible energy. This coefficient may vary widely - from 30 to 90 percent.
There are such five types of recuperators: lamellar, rotary, with intermediate coolant, chamber recrerators, thermal pipes. Plate repairs consist of a series of plates, on both sides of which the removed and flow air passes. The advantage of lamellar recoveors is high efficiency, 50-80% and a small price. The disadvantage of such recuperators is that condensate can be formed on their plates, and in the winter season, go.
In rotary recuperators, heat exchange occurs with a special rotor, which is between incoming and outgoing air flows. This system is open, therefore there is a very large risk that dirt and odors are transferred from the removable air removable. The effectiveness of such recuperators reaches 90%.
The recuperators with an intermediate coolant are arranged as: the coolant (water or water-glycol solution) moves from one coolant to another, taking the heat from the outgoing air and transmitting it an incoming flow. The effectiveness of such devices is low - 45-60%.
In chamber recuperators, the heat exchange process is adjusted by the damper in the chamber. The outgoing air flow heats up one of the parts of the chamber, and already from the camera walls the incoming air is obtained. The effectiveness of such recuperators is 70-80%.
The fifth type of recuperators is "thermal pipes". The main part of such a system is the tubes in which Freon is located. Removed air heats freon, which evaporates. Passionate air, passing along the tubes, causes Freon to condense - thus cooling the air flow.

On the eve of the cold weather, the issue of heat conservation becomes relevant. Along with such standard measures, as the insulation of the perimeter of the house, there are more technological, and most importantly, less expensive techniques. One of them is heat recovery.

Efficiency of recuperator

How well the tallane-exchange device copes with its task, you can understand this indicator as the efficiency coefficient of recovery. This value is the ratio between the maximum possible amount of heat, which is permissible to transfer the air air, and the one that is obtained in reality. Depending on the device, the coefficient ranges from 30 to 95%.

ADVANTAGES AND DISADVANTAGES

Due to the recovery, the amount of thermal energy required for heating housing is reduced. And therefore, the costs of developing this energy are reduced. You can save and on the work of the air conditioner in summer. However, before the release-exhaust installation (PDA) based on the recovery, it will start working and pay off, it will require certain attachments that may be very tangible.
HOW IT WORKS

The heat recovery of thermal energy is a heat exchange process, in which the cold air entering the room is heated due to the removed warm. Similarly, the cooling recovery occurs: warm supply air masses are transmitted heat output to the exhaust air and thus cooled. Special devices are used to organize heat transfer - recuperators. In essence, these are heat exchangers through which supply and exhaust air flows pass without mixing by another friend.

Useful advice

The heat exchanger functionality can be wider than simply cooling or air heating. Modern devices are often equipped with purification filters, humidifiers, ionizers, noise suppression system and other utility devices. But, acquiring such a device, you should be prepared for a periodic replacement of consumables, which will require additional costs.

System equipment. In modern practice, a single ventilation system is rarely applied. It is much more advantageous to divide the premises on the groups by the method of using them and design ventilation for each group separately. For example, if in a two-storey building in winter it is planned to constantly use only the first floor, it is reasonable to schedule the PVE with the recovery for the first floor.

Types of recuperators

Placer

The design of this type implies the presence in the heat exchanger of special wave-like plates made of sheet material, well conductive heat (aluminum, steel). Plates in the amount of 60-70 pieces are mounted in a single block (radiator) so that the channels formed by the "wave" passes cross each other - to create turbulence and. Accordingly, the best heat exchange. The radiator is arranged so air masses having different temperatures are not mixed with each other. The main disadvantage is the risk of plate frost. On the walls of the mechanism, the moisture is settled, which is with a warm stream. If the temperature of the incoming air is very low, then ice formation is possible at the outlet of the warm stream. Therefore, the cold trifting air periodically needs to be allowed directly - that is, bypassing the recuperator, so that the leafy air defects the recuperator.

Liquid

It consists of two heat exchangers interconnected by a pipeline with a circulating liquid coolant. As the latter, a solution of propylene glycol in distilled water is usually used. Heated in the heat exchanger exhaust channel, the liquid through the heat exchanger in the supply channel transmits heat to the incoming air. The system does not freeze and can serve premises with a large area, but in residential buildings it is rarely used due to complexity and high costs.

Rotary

In this modification, the rotor is the rotating cylinder from corrugated steel as a heat exchanger. Warring from exhaust air, the rotor, making the floor turnover, transmits heat to the supply stream. The advantage of the mechanism is that it is not exposed to the risk of frost. Such a device does not need a "defrost". Therefore, its efficiency can reach 95 hours. The disadvantage is difficult to avoid mixing air flows. In addition, the rotor partially transmits smells that the outgoing air is saturated.

How to choose a recuperator?

Built in PWR

The optimal option is initially designing a ventilation system with a built-in recuperator. In this case, we are talking about the acquisition of the PVE, in the design of which the heat exchanger is already included. The main selection criterion is the performance of the entire system as a whole (m³ / h). It is calculated based on the total air volume indoors and the multiplicity of air update. Calculate the air volume - elementary, it is necessary to multiply the area of \u200b\u200bthe house to the height of the ceilings (V \u003d S × H). The brevity is chosen in accordance with the purpose of the room. For residential premises enough so that the air is completely updated once per hour. For kitchen, bathroom and other rooms with different smells or high humidity, multiplicity should be increased.

Not built in poultry

Sometimes the decision to acquire a recovery occurs after the ventilation is fully mounted. As a result, the task appears to select a device for the already ready and acting air exchange system.

When choosing, it is necessary to focus on the total supply of air, which passes through all the fans to the heat exchanger. The productivity of the unit must be 25 hours less than this value, otherwise it will not work fully and may be useless.

The crown of that, you need to pay attention to the holes for connecting the air ducts. It is desirable that the sizes and configuration of these holes are the same as the air channels in the ventilation system otherwise, problems with mounting the device may occur.

Useful advice

Plate recovery

compared with rotary with similar characteristics, as a rule, cheaper. In addition, it is more maintained: there are no complex moving mechanisms in it, and it is easy to fix it with their own hands. However, the risk of icing plates makes it less reliable in operation. Choosing a similar unit, you should pay attention to the models with a thermal battery that protects the device from the formation of land.

Rotary recuperator

Since the rotor comes into contact with the outgoing air containing pollution, then with fresh incoming air, cleaning the rotor and the replacement of filters will have to be produced more often. It is not necessary to install rotary heat recoveors for the ventilation systems of rooms in which strong smells (kitchen, workshop) are possible.

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In connection with the growth of tariffs for primary energy resources, recovery becomes more relevant. The following types of recoveors are usually used in the recuperation-exhaust plants with recovery:

• plate or cross-accurate heat recuperator;
• rotary heat recovery;
• recuperators with intermediate coolant;
• heat pump;
• camera type recuperator;
• recuperator with thermal pipes.

Principle of operation

The principle of operation of any recuperator in the supplied and exhaust installations is as follows. It provides heat exchange (in some models - and cold exchange, as well as moisture exchange) between flow and exhaust air flows. The process of heat exchange can occur continuously through the walls of the heat exchanger, using a chladone or an intermediate coolant. Can heat exchange be and periodic, as in a rotary and chamber recuperator. As a result, the ejectible exhaust air is cooled, thereby heating the fresh difts. The cooling process in separate models of recuperators takes place in the warm season and allows to reduce energy consumption on air conditioning systems due to some cooling supplied air supplied. The moisture exchange goes between the streams of exhaust and supply air, allowing you to maintain a comfortable humidity for a person year-round, without using any additional devices - humidifiers and others.

Plate or cross-accurate heat recuperator.

The heat-conducting plates of the recuperative surface are made of fine metal (material - aluminum, copper, stainless steel) foil or from ultra-thin cardboard, plastic, hygroscopic cellulose. The streams of supply and exhaust air move along a plurality of small channels formed by these heat-conducting plates, according to the countercurrent scheme. Contact and mix streams, their pollution is almost excluded. In the design of the recuperator of moving parts no. The efficiency coefficient is 50-80%. In the recuperator from the metal foil due to the difference of temperature flow temperatures on the surface of the plates, moisture can be condensed. In the warm season, it must be removed into the system of sewage system at a specially equipped drainage pipeline. In the cold time there is a danger of freezing of this moisture in the recovery and its mechanical damage (defrost). In addition, the ice formed strongly reduces the efficiency of the recovery. Therefore, recuperators with metal heat-conducting plates are required during operation during the cold season of the periodic defrosting by the flow of warm exhaust air or the use of an additional water or electric air heater. At the same time, the tributarial air is not fulfilled at all, or is fed to the room bypassing the recovery through an additional valve (bypass). The defrost time is an average of 5 to 25 minutes. The heat-conducting recuperator with heat-conducting plates from the ultra-thin cardboard and plastic is not subject to frost, as moisture exchanges are under these materials, but it does not have a different drawback - it cannot be used to ventilate the premises with high humidity for the purpose of their drainage. The plate heat recuperator can be installed in the supply and exhaust system both in the vertical and horizontal position, depending on the requirements for the size of the ventalkamers. Plastic recreurators are the most common due to its relative ease of design and low cost.

Rotary heat recovery.

This type is second to the degree of propagation after the lamellar. The heat from one air flow to another is transmitted through a cylindrical hollow drum, called the rotor, rotating between the exhaust and supply sections. The internal volume of the rotor is filled with a tightly metallic foil or wire, which plays the role of a rotating heat transfer surface. The foil material or wire is the same as the lamellar recovery - copper, aluminum or stainless steel. The rotor has a horizontal axis of rotation of the drive shaft rotated by the electric motor with stepping or inverter adjustment. Using the engine, you can control the recovery process. The effectiveness coefficient is 75-90%. The efficiency of the recuperator depends on the temperatures of streams, their speed and rotational speed. By changing the rotor speed, you can change the efficiency of work. The freezing of moisture in the rotor is excluded, but the mixing of streams, their mutual pollution and the transmission of odors cannot be completely excluded, since the streams directly contact each other. It is possible to mix up to 3%. Rotary recovers do not require high energy costs, allow you to dry air in rooms with high humidity. The design of rotary recuperators is more complex than lamellar, and their cost and exploitation costs are higher. Nevertheless, the supply and exhaust installations with rotary recuperators are very popular due to their high efficiency.

Recuperators with intermediate coolant.

The coolant most often water or aqueous solutions of glycols. Such a recuperator consists of two heat exchangers interconnected by pipelines with a pump for circulation and reinforcement. One of the heat exchangers is placed in a channel with a stream of exhaust air and gets warmth from it. The heat through the coolant using a pump and pipes is transferred to another heat exchanger located in the channel air channel. Passionate air perceives it warm and heated. Mixing flows in this case is completely excluded, but due to the presence of an intermediate coolant, the efficiency coefficient of this type of recuperators is relatively low and is 45-55%. Performance can be affected by the pump, affecting the speed of the coolant. The main advantage and difference between the recovery with the intermediate coolant from the heat carrier with the heat pipe is that the heat exchangers in the exhaust and supply installations can be located at a distance of each other. The position for the installation of heat exchanger, pump and pipelines can be both vertical and horizontal.

Heat pump.

Relatively recently there was an interesting variety of heat recovery with an intermediate coolant - so-called. The thermodynamic heat exchanger, in which the role of liquid heat exchangers, pipes and pump plays a refrigerating machine operating in the heat pump mode. This is a peculiar combination of heat recovery and heat pump. It consists of two chladon heat exchangers - an air cooler evaporator and a capacitor, pipelines, a thermostatic valve, compressor and a 4-way valve. The heat exchangers are placed in the supply and exhaust air duct, the compressor is necessary to ensure the circulation of the refrigerant, and the valve switches the refrigerant streams depending on the season and allows you to transfer heat from exhaust air into a trimming and vice versa. At the same time, the supply and exhaust system may consist of several intake and one exhaust installation of greater performance, combined with one refrigeration outline. In this case, the capabilities of the system allow multiple supply installations to operate in different modes (heating / cooling) at the same time. The coefficient of conversion of the thermal pump SOR can reach 4.5-6.5 values.

Recuperator with thermal pipes.

On the principle of operation, the heat pipe with heat pipes is similar to a recuperator with an intermediate coolant. The only difference is that non-heat exchangers are placed in air flow streams, and so-called thermal pipes or more accurate thermosifones. Structurally, these are hermetically closed segments of the copper finned pipe filled inside the specially selected light-boiling chladone. One end of the pipe in the exhaust stream is heated, the coolness in this place is boiling and transfers the heat perceived heat to the other end of the pipe, which flows into the stream of supply air. Here, the chladone inside the pipe is condensed and transfers the heat of air that heats up. Mutual mixing streams, their pollution and smell transmission are completely excluded. There are no mobile elements, the pipes in the flows are placed only vertically either under a slight bias so that the chladon moves inside the pipes from the cold end to hot due to gravity. The efficiency coefficient is 50-70%. An important condition for ensuring its work: the air ducts in which the thermosifones are installed vertically on each other.

Camera type recuperator.

The internal volume (chamber) of such a recuperator is divided into two halves. The damper from time to time moves, thereby changing the direction of movement of exhaust and supply air flows. The exhaust air heats one half of the chamber, then the flap sends the flow of the supply air here and it heats away from the heated walls of the camera. This process is repeated periodically. The efficiency coefficient reaches 70-80%. But in the design there are moving parts, in connection with which there is a high probability of mutual mixing, contamination of flows and transmission of odors.

Calculation of the efficiency of the recuperator.

In the technical characteristics of the recuperative ventilation attitudes, many manufacturers are as a rule, two values \u200b\u200bof the recovery coefficient are in terms of air and its enthalpy. Calculation of the efficiency of the recovery can be produced at a temperature or aerial enthalpy. The temperature calculation takes into account the explicit heat generation of air, and in the enthalpy - the moisture content of the air (its relative humidity) is taken into account. EnderTalpian calculation is considered more accurate. For calculation, source data is necessary. They are obtained by measuring the temperature and humidity of the air in three places: indoors (where the ventilation unit provides air exchange), on the street and in the section of the supply air distribution lattice (where the treated outer air falls from the room). The formula for calculating the efficiency of recovery on temperature is as follows:

KT \u003d (T4 - T1) / (T2 - T1)where

• Kt. - coefficient of efficiency of the heat recovery;
• T1. - outdoor temperature, OC;
• T2. - exhaust air temperature (i.e. indoor air), OS;
• T4. - Air supply air temperature, OS.

The enthalpy of air is the heat heating of the air, i.e. The amount of heat contained in it, assigned to 1 kg of dry air. Enthalpy is determined using the I-D of the state of the state of wet air, applies to it with points corresponding to the measured temperature and humidity in the room, on the street and supply air. The formula for calculating the efficiency of recovery by enthalpy is as follows:

KH \u003d (H4 - H1) / (H2 - H1)where

• Kh. - coefficient of efficiency of the recuperator on enthalpy;
• H1. - Enhaulpia of outdoor air, KJ / kg;
• H2. -Nalpia exhaust air (i.e. indoor air), KJ / kg;
• H4. - Enhaulpia of the supply air, KJ / kg.

Economic feasibility of applying aircraft-exhaust plants with recovery.

As an example, take a feasibility study of the use of ventilation plants with recovery in the systems of the supply and exhaust ventilation of the car dealership.

Initial data:

• object - car dealership with a total area of \u200b\u200b2000 m2;
• the average height of the premises is 3-6 m, consists of two exhibition halls, office zone and maintenance station (service station);
• for the supply and exhaust ventilation of the specified rooms, channel ventilation settings were selected: 1 unit with air flow 650 m3 / hour and with a power consumption of 0.4 kW and 5 units with an air flow 1500m3 / hour and a power consumed of 0.83 kW.
• the guaranteed range of external air temperatures for channel settings is (-15 ... + 40) OS.

To compare power consumption, we will calculate the power of the channel electrical air heater, which is necessary for heating the outer air during the cold season in the supply of a traditional type (consisting of a check valve, a channel filter, a fan and an electric air heater) with air flow 650 and 1500 m3 / hour, respectively. At the same time, the cost of electricity is accepted 5 rubles for 1kW * an hour.

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

The calculation of the power of the electric air heater is made according to the heat balance equation:

QH \u003d G * CP * T, WWhere:

• QN - the power of the air heater, W;
• G. - mass flow of air through an air heater, kg / sec;
• Cf. - Specific isobar air heat capacity. Cf \u003d 1000kj / kg * k;
• T. - The difference in air temperature at the outlet of the air heater and the input.

T \u003d 20 - (-15) \u003d 35 OS.

1. 650/3600 \u003d 0.181 m3 / s

p \u003d 1, 2 kg / m3 - air density.

G \u003d 0, 181 * 1, 2 \u003d 0.217 kg / s

QH \u003d 0, 217 * 1000 * 35 \u003d 7600 W.

2. 1500/600 \u003d 0, 417 m3 / s

G \u003d 0, 417 * 1, 2 \u003d 0, 5 kg / s

QH \u003d 0, 5 * 1000 * 35 \u003d 17500 W.

Thus, the use of heat recovery in the cold season with heat recovery instead of traditional using electrical air heaters allows to reduce electricity costs with one and the same amount of air supplied more than 20 times and thus reduces costs and accordingly increase the profit of the car dealership. In addition, the use of recovery installations allows to reduce the financial costs of the consumer to the energy of the premises in the cold season and on their air conditioning in the warm time by about 50%.

For greater clarity, we will produce a comparative financial analysis of the power consumption of systems of the supply and exhaust ventilation of the premises of the car dealership, equipped with recovery of heat-type heat recovery and traditional installations with electrical air heaters.

Initial data:

System 1.

Installations with heat recovery cost 650 m3 / hour-1Ed. and 1500 m3 / hour - 5th.

The total electric power consumption will be: 0.4 + 5 * 0.83 \u003d 4.55 kW * hour.

System 2.

Traditional channel supply and exhaust ventilation installations. With consumption 650m3 / hour and 5th. With a flow rate of 1500m3 / hour.

The total electrical power supply of 650 m3 / hour will be:

• fans - 2 * 0,155 \u003d 0.31 kW * hour;
• automation and valve actuators - 0.1kW * Hour;
• electric air heater - 7.6 kW * hour;

Total: 8.01 kW * hour.

The total electrical installation power by 1500m3 / hour will be:

• fans - 2 * 0.32 \u003d 0.64kW * Hour;
• automation and valve actuators - 0.1 kW * hour;
• electric air heater - 17.5 kW * hour.

Total: (18.24 kW * hour) * 5 \u003d 91,2 kW * hour.

Total: 91.2 + 8.01 \u003d 99,21kW * hour.

We accept the period of using heating in ventilation systems 150 working days per year at 9 o'clock. We get 150 * 9 \u003d 1350 hours.

Energy consumption of recovery installations will be: 4.55 * 1350 \u003d 6142.5 kW

Operational costs will be: 5 rubles. * 6142.5 kW \u003d 30712.5 rubles. or in relative (to the total area of \u200b\u200bthe car dealership of 2000 m2) expression 30172.5 / 2000 \u003d 15.1 rubles / m2.

The energy consumption of traditional systems will be: 99,21 * 1350 \u003d 133933,5 kW operating costs will be: 5 rubles. * 133933.5 kW \u003d 669667.5 rubles. Or in relative (to the total area of \u200b\u200bthe car dealership of 2000 m2) expression 669667.5 / 2000 \u003d 334.8 rubles / m2.

Lower an energy efficient house - the dream of each developer. Many believe that to achieve this goal, it is enough to warm the perimeter of the building and provide it with modern windows. But is it just solved by this question? It turns out no. Only insulation of the enclosing structures and installation of hermetic window blocks it is impossible to provide comfortable accommodation and a full-fledged energy saving of the building. For some reason, many forget to take into account even the need to use ventilation - supply-exhaust installations (PDA).

To preserve the inner heat of the room need suppress and exhaust ventilation to equip heat exchanger — recessable airwhich will dispose of heat outgoing from the air flow premises by giving it to the supply. Such systems are widely used in Western Europe, providing building buildings with a heat loss level of 5-10 times less compared to a conventional residential foundation. Due to the recycling of exhaust air heat, save up to 70% of heating costs And thus pay off in the shortest possible time, as a rule, it is 3-5 years.

Small-sized suppress-exhaust systems with heat recovery type AVTU, which are designed specifically for use in residential and other small rooms. They are served in the building of fresh, heated, purified by outdoor dust air.

The energy of ventilation emissions in modern buildings reaches 50% of the overall level of heat loss, so energy-efficient is called a building in which in addition to the insulation of the enclosing structures and the installation of hermetic window groups, the energy returned to the room by recycling the heat of ventilation emissions is used.

The duration of the heating season in energy efficient buildings can be reduced by more than a month.

Principle of operation of the PVU.

Is as follows. The heated air is closed by means of air intakes in the most wet rooms (kitchen, bathroom, toilet, economic room, etc.) and through the air ducts removed the outside of the building. However, before leaving the building, it passes through the heat exchanger of the heat exchanger, where it leaves a part of the heat. With this warmth, the cold air is heated outside (it also passes through the same heat-wedge, but in another direction) and is supplied inside (living room, bedrooms, cabinets, etc.). Thus, constant air circulation occurs inside the room.

Principle of operation of the supply and exhaust installation with heat recovery

Cutting-exhaust installation with a recuperator can be of different power and sizes - it depends on the volume of ventilated premises and their functional purpose. The simplest installation is an isolated thermally and acoustically and a set of interconnected elements interconnected interconnected elements: a heat exchanger, two fans, filters, sometimes a heating element, a condensate removal system (automation unit, elements of electrical strokes and air ducts in this context are not considered).

Organization of air exchange in residential cottage premises

Through the heat exchanger during the operation of the installation, two air flows pass - the internal and external, which are not mixed at the same time. Depending on the design of the heat exchanger, recuperators are several types.

The most far-sighted homeowners are designed in their buildings at once two ventilation systems: gravitational (natural) and mechanical with heat recovery (forced). The system of natural ventilation in this case is an emergency and serves as a challenge in the operation of the supply and exhaust installation and is mainly used in the unheated period. At the same time, it should be remembered that during operation of the mechanical ventilation system, the gravitational air ducts must be tightly closed. Otherwise, the effectiveness of forced ventilation will be lost.

Plate Reciperators

Removed and dying air pass on both sides of a row of plates. At the same time, a certain amount of condensate can be formed in the plate recuperators on the plates. Therefore, they should be equipped with condensate discharges. Condensate collectors must have a water shutter that does not allow the fan to capture and supply water into the channel.

Principle of operation of the supply and exhaust installation with heat recovery

Due to condensate loss, there is a serious risk of ice formation, and therefore the defrosting system is necessary. Heat recovery can be adjusted by a bypass valve controlling the flow rate passing through the air recuperator. There are no moving parts in the recovery plate. It is characterized by high efficiency (50-90%).

Plate recovery

It has been well established to install this type from the manufacturer TM Naveka - Node1. They have an aluminum heat recovery, a drainage system for condensate drain and a recovery protection system. As well as the quietest in its class fans, an electric or water heater, built-in automation and remote control with the setting of modes and work schedules.

Rotary recuperators

The heat is transmitted rotating between the removable and supply channels by the rotor. This is an open system, and therefore there is a great risk that dirt and smells can move from the removed air into the dying, which can be avoided to some extent if the fans are properly placed. The level of heat recovery can be adjusted by the rotor speed. In a rotary heat recovery, the risk of freezing is low. Rotary recuperators have moving parts. They are also characterized by high efficiency (75-85%).

Rotary recuperator

This solution is successfully implemented by the manufacturer TM Naveka in the Node3 series installations. Installations have a freezing system, built-in automation and remote control. Performance of Vertical - installations have heat-free insulation from mineral non-combustible wool 50 mm thick, and the possibility of outdoor (outdoor) installation and operation.

Recuperators with intermediate coolant

In this design, the coolant (water or water-glycolic solution) circulates between two heat exchangers, one of which is located in the exhaust channel, and the other is in the supply. The coolant is heated by removed air, and then transmits heat to the supply air. The coolant circulates in a closed system, and there is no risk of transmission of contaminants from the removed air to the trim. Heat transmission can be adjusted by changing the circulation rate of the coolant. These recoveors do not contain moving parts and have low efficiency (45-60%).

Recuperator with intermediate coolant

Chamber recuperators

In such a recuperator, the camera is divided into two parts of the flap. The removed air heats one part of the chamber, then the flap changes the direction of the air flow in such a way that the trim air is heated from the heated walls of the chamber. In this case, pollution and odors can be transmitted from the removed air to the trim. The only movable part of the recovery is the damper. The unit is characterized by high efficiency (80-90%).

Chamber recuperator

Heat tubes

This recuperator consists of a closed system of tubes filled with freon, which evaporates when heated by air removed. When the trim air passes along the tubes, steam condenses and turns into a liquid again. Transfer of contaminants in this design is excluded. The recuperator does not have mobile parts, but has relatively low efficiency (50-70%).

Channel Type Recuperator based on heat pipes

Plastic and rotary recoveors were most common in practice. Moreover, there are models of recuperators in which sequentially two plate heat exchanger can be installed. They are characterized by high efficiency.

Two-stage recovery by two rotors

The heat volume taken by means of a heat exchanger depends on a number of factors, in particular, the temperature of the internal and outer air, its humidity, the air flow rate. The more temperature difference inside and outside the room, the greater the humidity, the greater the effect of the recovery operation. By the way, most installations have the ability to mount for the summer period. instead of the usual heat exchanger of the so-called summer cassettethat allows you to provide air flow without recovery process. In addition, in some cases, you can change the direction of air flows inside the installation, so that they will bother the heat exchanger.

The main characteristics and features of the types of heat exchangers

Fans

Air movement provides fans - a trim and exhaust, although you can find systems with an integrated supply-exhaust fan that runs from one engine. In simple models, fans have three levels of revolutions: normal, reduced (used for work at night or in the absence of tenants, if it is a house or apartment) and maximum (used when you need the highest level of air exchange). Some modern fan models have much more degrees of speed, which makes it possible to better meet the needs of the system users in different degrees of ventilation intensity.

The operation of the fans can be controlled automatically. The control panel is usually installed indoors in places, convenient to use them. Temporary programmers ensure the establishment of the mode of rotation of the fans during the day or week. In addition, some advanced models can be integrated into the smart home system and manage the central computer. The operation of the recuperator may also depend on the level of humidity in the premises (for this you need to install the appropriate sensors) and even the level of carbon dioxide.

Since the ventilation system should work around the clock, high quality fans is an extremely important feature of the supply and exhaust installation.

Filters

The air, taking the outside, must be supplied to the room only passing through the filter. Usually, filters, delaying particles up to 0.5 microns, are installed in recuperators. Such a filter corresponds to the EU7 class by DIN or F7, according to Eurostandards. Thus, the filter delays dust, disputes of mushrooms, pollen of plants, soot.

This feature of the supply and exhaust installation should be appreciated by allergic. At the same time, the filter in front of the heat exchanger is also installed in the exhaust system. True, his class is somewhat lower - EU3 (G3). It protects the heat exchanger from pollution, which, along with air, removed from the premises. Filters are made from synthetic materials, they can be both single and reusable. The material of the latter should be easy in cleaning. Such filters can be shaken and washed. Some models of recovery installations have filter contamination sensors that at a certain point signals the need to replace or clean the filter.

Heating elements

Of course, the situation when the trim air is heated due to the removed heat, would be perfect. But in some cases it is impossible to achieve this. For example, if outside the window -25 ° C, then the temperature of the removed air, whatever the effectiveness of the heat exchanger, will not be enough to warm the trim air to a comfortable temperature. In this regard, recuperators are equipped with an electrical system of additional heating of air supplied to air. As practice shows, heated supply air is needed in the event that the temperature is less -10s outside the temperature.

The heating element is also controlled automatically and is turned on depending on the program, if the selected heat is not enough to heal the supply air in accordance with the specified parameters. It is usually mounted along with the heat exchanger. Power and sizes of heating elements depend on the power of the entire installation.

It happens that with a large humidity of air and a strong frost on the heat exchanger, condensate is formed, which can freeze. To avoid this phenomenon, there are several technical solutions.

For example, a trim fan can work with breaks (turn on every half an hour for five minutes), and then running the exhaust fan, and warm air, passing through the heat exchanger, protects it from the formation of land.

The second, fairly common solution is to send part of the flow of cold air by the heat exchanger. There are a number of other methods, up to the use of an electric heater, which partially heels the air incoming outside the heat exchanger. The resulting condensate should not be assembled inside the unit, but to be removed through the system of pipelines or directly into the sewage system, or to another space provided by the project.

During the construction of individual houses, it is possible to apply the constructive scheme of the device of the forced ventilation system with a fence of air at a certain distance from home and delivery to a supply-exhaust unit by means of air ducts in the ground, below the level of primerization of the soil. During the passage of such a channel, the air temperature will increase, which reduces the risk of condensate formation and land on the heat exchanger and in general increases the efficiency of the recovery.

Air ducts

As we have noted, the installation of the supply and exhaust ventilation is much easier to perform in the building under construction than in the already exploited. Consequently, its design should be an element of the entire construction project. Typically, the installation is placed on unused attics (it is easier to provide a fence of cleaner air), in basements, boiler houses, economic and utility rooms. It is important that it was a dry room with positive temperatures. Air ducts in the unheated room must be heat insulated. Inside the premises, they are usually mounted behind suspended ceilings.

Aluminum or plastic flexible air ducts

In practice, various types of air ducts are used. Most convenient installation - Aluminum or plastic flexible ducts in the form of a pipereinforced with steel wire. Pipes can also be insulated with mineral wool. A ducts of rectangular or square sections are used. Ventilation grilles are usually mounted in walls or ceilings. Specialists are recommended as the most convenient option to use anestat-adjustable anemostats for the influx of air, although regular lattices are still used for these purposes. The intake air fence should be made in places where it is least susceptible to pollution.

In conclusion, several videos on the use of supply-exhaust plants with heat recovery:

Device and principle of operation of a plate heat recovery.

The use of air recuperator, as a fixed assessment to combat mold and fungi in a residential room.

In the process of ventilating from the room, not only exhaust air is disposed of, but also part of thermal energy. In winter, this leads to an increase in energy bills.

Reducing unjustified costs, not to the detriment of air exchange, will allow heat recovery in centralized and local-type ventilation systems. For thermal energy regeneration, different types of heat exchangers are used - recuperators.

The article describes in detail the models of the aggregates, their design features, principles of work, dignity and disadvantages. The outlined information will help in choosing the optimal option for the improvement of the ventilation system.

Translated from Latin, recovery means compensation or reverse receipt. With regard to heat exchange reactions, recovery is characterized as a partial return of energy spent on carrying out technological action in order to use in the same process.

In local recuperators, a fan and a plate heat exchanger are provided. "Sleeve" of the siftyer is isolated by a noise absorbing material. Compact juncture control unit is placed on the inner wall

Features of decentralized ventsystems with recovery:

• Kpd. – 60-96%;
• low performance - devices are designed to provide air exchange in rooms up to 20-35 sq.m;
• available cost and a wide selection of aggregates, ranging from conventional wall valves to automated models with a multistage filtering system and the possibility of regulating humidity;
• easy mounting - To commission, the air ducts are not required, you can independently.

  An important criteria for choosing a wall sifermon: the permissible wall thickness, performance, recuperator efficiency, the diameter of the air canal and the temperature of the pumped medium

  Conclusions and useful video on the topic

  Comparison of the work of natural ventilation and forced system with recovery:

  The principle of functioning of a centralized recuperator, the calculation of the efficiency:

  The device and order of the decentralized heat exchanger on the example of Prana wall valve:

  Through the ventsy system from the room takes about 25-35% of heat. Recovers are used to reduce losses and efficient heat removal. Climatic equipment allows you to use the energy of spent masses to heat the incoming air.

  Have something to complement, or have questions about the work of different ventilation recuperators? Please leave comments to publication, share the experience of using such installations. The form for communication is located in the bottom block.