Chamber recuperator. Air recuperator: what is it? Determination of the recovery factor

When building a house, it is necessary to select and install a system for heat recovery in ventilation systems. There are several modifications of ventilation equipment, which are chosen depending on its manufacturer. Natural impulse equipment includes wall and window vents to bring fresh air into the rooms. To remove odors from toilets and bathrooms, as well as from kitchens, exhaust ducts are installed.

Air exchange is obtained due to the temperature difference in the room and outside. During the summer, temperatures even out both inside and outside the rooms. That is, air exchange is suspended. In winter, the effect manifests itself more quickly, but it will require more energy to heat cold outdoor air.

Composite hood is a system with forced ventilation and natural air circulation. The disadvantages are:

poor air exchange in the house.

The advantages include low price and the absence of external natural factors. But at the same time, in terms of quality and functionality, aeration cannot be considered a full-fledged ventilation.

To provide comfortable conditions in new residential buildings install universal forced aeration systems. Systems with a heat exchanger ensure the supply of fresh air at a normal temperature with the simultaneous removal of exhaust air from the premises. Along with this, heat is removed from the discharge stream.

Saving thermal energy with supply and exhaust ventilation with recuperator // FORUMHOUSE

Depending on the types of recuperators and the size of the rooms in which ventilation is installed, the microclimate is improved more or less effectively. But even with installed recuperation with an efficiency of only 30%, energy savings will be significant, and the overall microclimate in the rooms will also improve. But heat exchangers also have disadvantages:

increase in electricity consumption;
condensate release, and icing occurs in winter, which can lead to damage to the heat exchanger;
loud noise during operation, causing great inconvenience.

Heat exchangers or heat recovery units in ventilation systems with enhanced heat and noise insulation operate very quietly.

Recuperators of the directed movement of heat carriers assume ventilation and utilization of warm exhaust air. The device moves air in two directions at the same speed. With heat exchangers, the comfort of life in houses increases.

At the same time, heating and ventilation costs are significantly reduced, combining both serious processes into one. Such devices can be used both in residential and in industrial premises. Thus saving Money will be approximately thirty to seventy percent. Heat exchangers can be divided into two groups: single action heat exchangers and heat pumps to increase the reserve of utilized heat. Heat exchangers can only be used in cases where the resources of the sources are greater than the resources of the microclimate to which heat energy is transferred.

Apartment ventilation system with Ecoluxe EC-900H3 recuperator.

Devices that transfer heat from sources to consumers using intermediate working fluids, for example, liquids circulating in closed circuits, consisting of circulation pumps, pipelines and heat exchangers located in heated and cooled chambers, are called recuperators with intermediate heat carriers. Such equipment is widely used in various heat exchangers and circulation pumps at large distances between the source and consumer of heat.

This principle is used in an extensive system of heat recovery and energy consumers with different characteristics. The operation of a heat exchanger with an intermediate heat carrier is that the process in it proceeds in the range of water vapor with a change in the state of aggregation at a constant temperature, pressure and volume. The operation of heat recovery units with heat pumps is different in that the movement of the working fluid in them is produced by a compressor.

Efficiency of the heat exchanger pipe in the pipe in the fall. +6g.C. on the street.

Mixed action devices

For disposal and for heating supply air use exchangers of recuperative or contact type. Mixed-action devices can also be installed, that is, one - recuperative action, and the second - contact. It is desirable to install intermediate coolants that are harmless, inexpensive, non-corrosive in pipelines and heat exchangers. Until recently, only water or aqueous glycols acted as intermediate heat carriers.

At the moment, their functions are successfully performed by the refrigeration unit, which works as a heat pump in combination with a heat exchanger. Heat exchangers are located in the supply and exhaust air ducts, and with the help of a compressor, freon is circulated, the flows of which transfer heat from the exhaust air stream to the supply air and vice versa. It all depends on the time of year. Such a system consists of two or more, which are united by one refrigeration circuit, which ensures synchronous operation of the units in different modes.

Features of plate and rotor designs

The most simple design at the plate heat exchanger. The basis of such a heat exchanger is hermetic chamber with parallel air ducts. Its channels are separated by steel or aluminum heat-conducting plates. The disadvantage of this model is the formation of condensate in the exhaust ducts and the appearance of an ice crust in winter time. When the equipment is defrosted, the incoming air goes to the heat exchanger, and the warm outgoing air masses contribute to the melting of ice on the plates. To prevent such situations, it is preferable to use plates made of aluminum foil, plastic or cellulose.

Rotary heat exchangers are the most highly efficient devices and are cylinders with corrugated metal layers. As the drum set rotates, a warm or cold air stream enters each section. Since the efficiency is determined by the rate of rotation of the rotor, it is possible to control such an apparatus.

The advantages include the return of heat of approximately 90%, the economical use of electricity, humidification of the air, the shortest payback period. To calculate the efficiency of the heat exchanger, it is necessary to measure the air temperature and calculate the enthalpy of the entire system using the formula: H = U + PV (U - internal energy; P - system pressure; V - system volume).

In a house where the ventilation system works well, a person feels very comfortable and gets sick less.

However, to ensure traditional good ventilation, it is necessary to significantly increase the cost of heating and air conditioning (to maintain normal air temperature in the house).

What is an air recuperator?

Nowadays, an improved ventilation system is used with the use of special devices that can significantly reduce heat loss in winter when exhaust air is extracted and prevent heat from entering the house in summer when superheated air is supplied from the street. This device called air recuperator , photo 1.

Photo 1. Air recuperator in the ventilation system of the house

At correct installation and operation, the air recuperator is able to “return” 2/3 of the heat that leaves with the recycled air. All recuperators contain in their structure filters for cleaning the supply air and, depending on the modification, there may be a different quality of cleaning.

Advantages of using an air recuperator in a general ventilation system:

Reduces heating and ventilation costs (up to 30...50%).
Comfortable microclimate in the house, constantly fresh air.
Reduces the level of dust in the house.
Low operating costs.
Not a difficult installation.
The equipment is durable.

Air recuperator design

The air recuperator consists of two chambers that run close to each other, photo 2. Heat exchange takes place between the chambers, which allows heating the supply air flow in winter due to the heat of the exhaust flow, and vice versa in summer.

Photo 2. circuit diagram air recuperator operation

Types of recuperators

Air recuperators are of the following types.

lamellar;
rotary;
water;
roofing.

Plate heat exchanger

Plate heat exchanger represents the case in which pipes of rectangular section enter and leave. On one side, two pipes are in contact, which ensures heat exchange between them. Inside the pipes are galvanized plates that heat up, cool down and transfer heat, photo 3. In a plate heat exchanger, supply and exhaust air flows do not mix.

The plates are made of a material that has a high thermal conductivity, these include:

special plastic;
copper;
aluminum.

Photo 3. Plate air heat exchanger

Advantages of a plate air heat exchanger :

compact;
relatively inexpensive;
silent operation;
high performance of the device (efficiency is 45 ... 65%);
no electric drive and dependence on electricity;
high service life (practically do not break).

Disadvantage of plate air heat exchanger:

In winter, in frost, there is a high probability of freezing of the exhaust mechanism.
Moisture exchange is not performed.

photo 4) consists of the following main elements:

cylinder;
rotating drum (rotor);
frame.

Inside the cylinder there are many thin corrugated metal plates (heat exchangers).

Photo 4. Rotary heat exchanger

With the help of a rotating drum, the heat exchanger operates in two modes:

1 - passing the exhaust flow from the room;

2 - passing the supply air flow.

The operation of the rotary heat exchanger is controlled by its electronics, which, depending on the external and internal temperatures, determines the number of revolutions and the operating mode. Thus, the metal plates either heat up or give off heat.

The rotary heat exchanger may have one or two rotors.

Advantages of a rotary heat exchanger:

High efficiency device. The efficiency reaches up to 87%.
In winter, the device does not freeze.
Doesn't dry out the air. Partially returns moisture back to the room.

Disadvantages of a rotary heat exchanger:

Large equipment dimensions.
Dependence on electricity.

Application area:

private home;
Office rooms.
Garages.

Water recuperator

Water recuperator (recirculation) - this is a heat exchanger in which water or antifreeze serves as a heat exchanger, photo 5. This heat exchanger is similar in design to a traditional heating system. The heat exchanger fluid is heated by the outgoing air, and the supply air is heated by the heat exchanger.

Photo 5. Water recuperator

Advantages of a water recuperator:

The normal indicator of work efficiency, efficiency - 50 ... 65%.
The ability to install its individual parts in different places.

Disadvantages of a water recuperator:

Complicated design.
Moisture exchange is not possible.
Dependence on electricity.

is a recuperator industrial use. The efficiency of this type of heat exchanger is 55…68%.

This equipment is not used for private houses and apartments.

Photo 6. Roof air recuperator

Main advantages:

Low cost.
Trouble-free work.
Ease of installation.

Recuperator of own production

If you have a desire, then you can make your own air recuperator. To do this, you can carefully study the schemes of recuperators that are on the Internet and determine the main dimensions of the device.

Consider the sequence of work:

The choice of materials for the recuperator.
Production of individual elements.
Manufacturing of a heat exchanger.
Assembly of the body and its insulation.

The easiest way is to make a plate-type heat exchanger.

For the manufacture of the case, you can use the following materials:

sheet metal (steel);
plastic;
wood.

To insulate the body, you can use the following materials:

fiberglass;
mineral wool;
Styrofoam.

Konev Alexander Anatolievich

Recovery is the process of returning the maximum amount of energy. In ventilation, recuperation is the process of transferring heat energy from exhaust air to supply air. There are many various kinds recuperators and in this article we will talk about each of them. Each type of heat exchanger is good in its own way and has unique advantages, but any of them will allow you to save at least 50%, and more often up to 95%, on supply air heating in winter.

The process of heat transfer from the exhaust air to the supply air is very interesting. Next, we will begin to disassemble each type of air recuperator so that you can more easily understand what it is and what kind of recuperator you need.

The most popular type of recuperators, or rather air handling units with a plate heat exchanger. It gained its popularity due to the simplicity and reliability of the design of the heat exchanger itself.

The principle of operation is simple - two air flows (exhaust and supply) intersect in the heat exchanger of the heat exchanger, but in such a way that they are separated by walls. As a result, these streams do not mix. Warm air heats the walls of the heat exchanger, and the walls heat the supply air. The efficiency of plate heat exchangers (efficiency of a plate heat exchanger) is measured as a percentage and corresponds to:

45-78% for metal and plastic heat exchangers of recuperators.

60-92% for plate heat exchangers with cellulose hygroscopic heat exchangers.

Such a jump in efficiency in the direction of cellulose recuperators is due, firstly, to the return of moisture through the walls of the recuperator from the exhaust air to the supply air, and secondly, to the transfer of latent heat in the same moisture. Indeed, in recuperators, the role is played not by the heat of the air itself, but by the heat of the moisture contained in it. Air without moisture has a very low heat capacity, and moisture is water ... with a known high heat capacity.

For all recuperators, except for cellulose, it is obligatory to remove the drainage. Those. when planning the installation of a heat exchanger, you need to remember that a sewerage supply is also required.

So the pros:

1. Simplicity of design and reliability.

2. High efficiency.

3. Lack of additional electricity consumers.

And, of course, the cons:

1. For the operation of such a heat exchanger, both supply and exhaust must be supplied to it. If the system is designed from scratch, then this is not a minus at all. But if the system is already available and the inflow and exhaust are at a distance, it is better to apply.

2. When sub-zero temperatures the heat exchanger of the heat exchanger may freeze up. To defrost it, either the cessation or reduction of the air supply from the street is required, or the use of a bypass valve that allows the supply air to bypass the heat exchanger while it is defrosting exhaust air. With this defrosting mode, all cold air enters the system bypassing the heat exchanger and a lot of electricity is required to heat it up. The exception is cellulose plate heat exchangers.

3. Basically, these recuperators do not return moisture and the air supplied to the premises is too dry. The exception is cellulose plate heat exchangers.

The second most popular type of recuperators. Still ... High efficiency, does not freeze, more compact than lamellar, and even returns moisture. Some pluses.

The rotary heat exchanger is made of aluminum, wound in layers on the rotor, with one sheet flat and the other zigzag. For air to pass. It is driven by an electric drive through a belt. This “drum” rotates and each part of it heats up when passing through the exhaust zone, and then, moving to the inflow zone, it cools, thereby transferring heat to the supply air.

A purge sector is used to protect against air overflows.

A new and not very well-known type of air recuperators. Roof heat exchangers actually use plate heat exchangers and sometimes rotary heat exchangers, but we decided to make them a separate type of heat exchangers, because. The roof heat exchanger is a specific separate type of supply and exhaust units with a heat exchanger.

Roof heat exchangers are suitable for large one-volume rooms and are the pinnacle of ease of design, installation and operation. To install it, it is enough to make the necessary window in the roof of the building, put a special "glass" that distributes the load, and put a roof heat exchanger in it. Everything is simple. Air is taken from under the ceiling in the room, and according to the wishes of the customer, either from under the ceiling or into the breathing zone of workers or visitors to shopping centers.

Recuperator with intermediate heat carrier:

And this type of recuperators is suitable for existing ventilation systems "inflow separately - exhaust separately".

Well, or if it is impossible to build a new ventilation system with any type of heat exchanger, which involves supplying inflow and exhaust to one room. But it is worth remembering that both plate and rotary heat exchangers have a higher efficiency than glycol ones.

Ecology of consumption. Manor: Heat loss - serious problem with which building science is struggling. Effective insulation, sealed windows and doors solve it only partially. Heat leakage through walls, windows, roofs and floors can be significantly reduced. Despite this, the energy has one more wide way to "escape". This is ventilation, without which it is impossible to do in any building.

Heat loss is a serious problem that building science is struggling with. Effective insulation, sealed windows and doors solve it only partially. Heat leakage through walls, windows, roofs and floors can be significantly reduced. Despite this, the energy has one more wide way to "escape". This is ventilation, without which it is impossible to do in any building.

It turns out that in winter we spend precious fuel on heating the premises and at the same time continuously throw heat out into the street, letting in cold air.

The problem of energy saving can be solved with the help of a heat recuperator. In this device, warm room air heats the outdoor air. This achieves considerable savings in heating costs (up to 25% of the total cost).

In the summer, when it is hot outside, and the air conditioner is working in the house, the recuperator also benefits. It cools the hot inlet stream, reducing air conditioning costs.

Let's take a closer look at household recuperation units in order to have an idea about their design, advantages and features of choice.

Types, principle of operation and device of recuperators

The idea to use the heat of room air to heat the outside turned out to be very fruitful. It was the basis for the operation of all recuperators.

Today, three types of such devices are used:

lamellar;
rotary;
recirculating water.

The most common and simple in design are plate heat exchangers. They are non-volatile, compact, reliable in operation and have a fairly high efficiency (40-65%).

The main working part of such a device is a cassette, inside which parallel plates are installed. The air leaving the room and entering it is cut by them into narrow streams, each of which goes through its own channel. Heat transfer occurs through the plates. Outdoor air is heated, while indoor air cools and is released into the atmosphere.

The principle of operation of a plate heat exchanger

The main disadvantage of lamellar installations is freezing in severe frosts. The condensate that settles in the recovery unit turns into ice and drastically reduces the performance of the device. Three methods have been found to combat this phenomenon.

The first is to install a bypass valve. Having received a signal from the sensor, it starts up a cold stream bypassing the block. Only warm air passes through the plates, defrosting the frost. After defrosting and removal of condensate, the valve restores the normal operation of the system.

The second option is to use hygroscopic cellulose plates. Water settling on the walls of the cassette is absorbed into them and penetrates into the channels through which the supply air moves. This solves two problems at once: the elimination of condensate and humidification.

The third way is to preheating cold stream to a temperature that excludes freezing of water. To do this, a heating element is placed in the supply ventilation duct. The need for it arises when the outdoor air temperature is below -10C.

AT last years plate reversing units appeared on the market. Unlike direct-flow devices, they operate in two cycles: the first is the release warm air to the street, the second - the suction of the cold through the heated block.

The principle of operation of the reversible installation

Another type of installation is rotary recuperators. The efficiency of such devices is significantly higher than that of lamellar ones (74-87%).

The principle of operation of the rotary unit is the rotation of the cassette with cells in the flow of incoming and outgoing air. Moving in a circle, the channels alternately pass warm internal and cold external flows. Moisture in this case does not freeze, but saturates the supply air.

It should be noted that the supply and exhaust unit with a rotary heat exchanger allows you to smoothly adjust the heat transfer. It is done by changing the speed of rotation of the cassette. The main disadvantage of rotary systems is the high cost of maintenance. In terms of reliability, they are also inferior to lamellar ones.

The next view is a recirculating water plant. It is the most complex in design. The heat transfer here is not carried out through the plates or the rotor, but with the help of antifreeze or water.

The first liquid-air heat exchanger is placed on the exhaust duct, and the second on the suction duct. The work goes on the principle of a heater: room air heats water, and it heats the street.

The efficiency of such a system does not exceed the performance of plate heat exchangers (50-65%). The high price that has to be paid for the complexity of the design is justified by the only advantage: the blocks of such an installation can be placed not in one building, but in areas of supply and exhaust ventilation that are remote from each other. For powerful industrial systems, this is of great importance. In small buildings, such devices are not installed.

Features of choosing a recuperator

Having got acquainted with the peculiarities of the work of recuperative units, it's time to move on to the practical part - the selection criteria for performing specific tasks.

The first thing you need to pay attention to is the installation method. In the working position, domestic supply and exhaust ventilation with heat recovery can be installed in several ways:

Inside the wall. The housing is mounted in a pre-drilled hole. A cap is placed on the outside, a grill and a control unit on the inside.

Indoors. The unit is hung on the wall. A grille or cap is placed outside.

Outdoor placement. The advantages of this solution are obvious: minimum noise and space saving. The channel device of the device allows you to place it on balconies and loggias, as well as just on the facade of the building.

Another parameter to consider when buying is the number of fans. Budget air recuperators for the home are equipped with one ventilation unit that works both for supply and exhaust.

More expensive devices have 2 fans. One of them pumps in, and the other throws out air. The performance of such devices is higher than single-fan.

When buying, you should also pay attention to the presence of an electric heater. With its help, freezing of the cassette is excluded and the lower temperature limit of the device operation is increased.

Climate control function. Allows you to precisely set the temperature to which the heat exchanger will heat the air.

Possibility of regulation of humidity. This parameter significantly affects the comfort of the microclimate. A standard heat exchanger dries the air by removing moisture from it.

The presence or absence of a filter. An additional option that positively affects the sanitary characteristics of the air mixture.

An important parameter that requires attention is the temperature of the pumped air. AT different models its meaning may differ significantly. The widest possible operating temperature range from -40 to +50C home appliances is rare.

Therefore, in addition to taking into account the optimal performance in m3 / h, when buying, choose a device that can fully work in your climatic conditions.

Performance calculation

Detailed calculations of the operation of recuperators in the supply and exhaust ventilation system are quite complex. Many factors have to be taken into account here: the frequency of air exchange in the premises, the cross section of the channels, the speed of air movement, the need to install silencers, etc. Only experienced engineers can competently perform such a task.

An ordinary consumer can use a simplified methodology in order to correctly navigate when buying a device.

The performance of the heat exchanger directly depends on the sanitary norm of air consumption per 1 person. Its average value is 30 m3/hour. Therefore, if 4 people permanently live in an apartment or a private house, then the installation performance should be at least 4x30=120 m3/hour.

Own electric power of household recuperators is small (25-80 W). It is determined by the level of energy consumption of duct fans. In installations with electric heating of the incoming flow, heating elements with a total capacity of 0.8 to 2.0 kW are installed.

Popular brands and estimated prices

When choosing a household heat exchanger, you should focus on manufacturers and models that deserve high marks buyers. As an example, we can cite the products of foreign companies Electrolux (Electrolux), Mitsubishi (Mitsubishi), Marley (Marley).

Heat exchanger for small rooms Mitsubishi Electric VL-100EU5-E. Air consumption 105 m3/h. Price from 21,000 rubles.

A popular model from Electrolux. Estimated retail price from 42,000 rubles.

The 2017 price tags for household installations of these brands start at 22,000 rubles and end at 60,000 rubles.

MARLEY MENV-180. Air consumption 90 m3/hour. Cost from 27,500 rubles.

The equipment of Russian and Ukrainian companies Vents (Vents), Vakio (Vakio), Prana and Zilant has proven itself well. Not inferior to foreign counterparts in performance and reliability, they often turn out to be more affordable.

Installing Vakio. Capacity 60 m3/h in recovery mode, up to 120 m3/h in supply ventilation. Price from 17,000 rubles.

The estimated cost of air recovery systems of these companies (capacity from 120 to 250 m3/hour) is from 17,000 to 55,000 rubles.

Prava 200g. Inflow - 135 m3/h, extract - 125 m3/h. The recommended area for system maintenance is up to 60 m2.

The nature of reviews about air recuperators is mostly positive. Many owners note that with their help, the problem of excessive humidity, which caused the appearance of mold and fungus in the premises, was solved.

In the calculations of the payback period for this equipment, figures from 3 to 7 years are given. We did not find data on instrumental measurements of real energy savings on forums dedicated to this topic.

Briefly about self-assembly

In most photo and video instructions for self-manufacturing recuperators are considered plate models. This is the simplest and affordable option for the home master.

The main part of the design is the heat exchanger. It is made of galvanized steel, cut into plates 30x30 cm in size. To create channels at the edges and in the middle of each section, plastic strips 4 mm thick and 2-3 cm wide are glued with silicone.

The heat exchanger is assembled by laying and alternately turning the plates at an angle of 90 degrees relative to each other. So get isolated channels for the oncoming movement of cold and warm air.

After that, a housing made of metal, chipboard or plastic is made to fit the dimensions of the heat exchanger. It has four holes for air supply. Fans are installed in two of them. The heat exchanger is turned at an angle of 45 degrees and fixed in the housing.

Thorough sealing of all assembly joints with silicone completes the work.