Heating a house using supply and exhaust air supply systems

Recommendation points

• Principle of operation
• Benefits of home heating with air
• Types of air heating systems
• Direct-flow
• Recirculating
• The specifics of self-installation
• The cost

An efficient heating system is an essential component of any home. While many homeowners are familiar with the traditional water system, not everyone is familiar with an alternative method of air heating. We will tell you about all the nuances of organizing an air heating system and its advantages in the article.

Principle of operation

The basis of the air heating system is the continuous supply and distribution of warm air throughout the premises, and the heat generator copes with the role of the key element. It is he who is responsible for heating the air mass to 45-65 ° C, which then enters the rooms through the air ducts.

The most popular today are heat generators operating on gas or electricity. In modern energy-efficient houses, geothermal heat generators, solar collectors and other, clean energy sources are used along with air heating. Air circulation can be organized in the following ways:

• natural when air moves due to a temperature gradient;
• forced, as a result of the operation of fans.

It is important to understand that heating a room with air presupposes a complex process of regulating heat, because directly heating the air is complemented by ventilation of the premises..

1. Air preparation unit. 2. External air ducts. 3. Internal supply duct. 4. Internal exhaust duct. 5. Air distribution grille or diffuser

Benefits of home heating with air

Among the advantages are the following:

1. Reliable performance and zero chance of freezing.
2. Economic benefit. Heating is harmoniously combined with air conditioning, humidification or air purification with a single air duct network, which will allow its owner to save a lot on installation and materials..
3. Heating the premises with air eliminates additional heat consumption for heating radiators and other structural elements, which cannot be said about water heating.
4. System automation capability.
5. The minimum time to warm up the room to the desired temperature. Taking into account the parameters of the working system and the dimensions of the room, the warm-up time reaches 40-60 minutes.
6. Lack of intermediate heat carrier (water).
7. There is no need to install heating radiators, the air ducts can be easily hidden in the walls and ceiling.
8. Simplicity and availability of installation, ease of maintenance.
9. Correct organization of the system and its operation allow the use of air heating for a long time.

Despite its efficiency and rationality, the system is not devoid of a number of disadvantages, for example, noise is a frequent guest in a heated house. For uniform heating, active air circulation in the room is required. Accurate calculation and accurate distribution of air ducts is required in order to eliminate temperature differences near the floor and under the ceiling, and at the same time do not create strong drafts and air currents.

For concealed installation of supply and exhaust ventilation channels, flat rectangular channels are used

Adequate air conditioning involves humidity control and filtration, which complicates the design of the heating system. For even distribution, an extensive and balanced network of air ducts is required, which can only be laid during the construction of a house or major repairs.

Air heating is quite reasonably combined with a ventilation system. The requirements for the functioning and performance of these systems can be found in the Code of Rules SP 60.13330.2012 and SNiP 41-01-2003. When self-designing and assembling air heating, do not forget about the various requirements for ventilation of living quarters, kitchens, bathrooms and utility rooms..

Types of air heating systems

According to the principle of operation, air heating can be direct-flow and recirculated. Each of these methods has its own specific features and recommendations for design and operation..

Direct-flow

The functioning scheme is quite simple:

1. The heat generator generates heat, which is fed to the air heat exchanger.
2. The fan blows air from the street with pre-filtration and passes it through the heat exchanger.
3. Hot air is distributed through air ducts throughout the premises.
4. The hood takes the exhaust air from the room directly to the street.

The supply and exhaust air volume is selected to ensure the required air exchange rate and depends on the internal volume of all heated rooms. There should be a little more air supply to create increased pressure in the house in order to exclude cold air from sucking in from cracks, windows and doors.

This system is extremely simple to implement, but very expensive to operate. The heat generator needs to heat cold air from the street to a comfortable temperature in a direct-flow mode, while the hood actively releases the still warm air after the first passage through the premises. Perfect for heating a small country house or summer cottage.

1. Air duct. 2. Filter. 3. Duct fan. 4. Electric instantaneous air heater

Recirculating

The air from the premises is not discharged into the street. It returns to the heat exchanger through the ventilation ducts and heats up again. The air in the room repeatedly passes through the heating system, and to heat it, a minimum of energy is required, which is necessary only to replenish natural heat losses. This heating method is economical, but in its simplest form it does not meet hygiene requirements, because dust and carbon dioxide constantly accumulate in a closed system..

A recirculated air heating system efficiently reuses the air from the room, not letting heat out aimlessly, but still provides fresh air from the street.

There are two design options:

1. Natural circulation (gravity system).
2. With forced supply and exhaust ventilation.

In the first case, hot air from the heat generator enters the premises through the ventilation ducts, where it cools down, under the action of gravitational forces it goes down back to the heat exchanger. Simple implementation and a minimum of initial investment is combined with energy independence, but is ineffective for maintaining a comfortable microclimate. A significant difference in air temperature near the floor and under the ceiling forms in the building.

Diagram of a gravitational air heating system. 1. Heat generator. 2. Air ducts. 3 Ventilation grilles in the supply line with adjustable louvers. 4. Ventilation grilles or exhaust diffusers

Combined with a full-fledged supply and exhaust ventilation system, heating with recuperation gives maximum effect and full control of the microclimate in the house.

From the room, the air enters the recirculation, where coarse and fine filters pass. Part of it is discharged into the street, and its place is taken by a portion of fresh air, mixing with recuperation. This is followed by heating and, if necessary, humidification or dehumidification. Conditioned air re-enters the premises.

Recirculated air heating is the most efficient and sophisticated. Energy is spent only on replenishing the heat loss of the house through the enclosing structures and during air renewal in the optimal volume, sufficient to create a comfortable microclimate.

Air preparation and recuperation unit. 1. Dampers with servo control. 2. Inlet air filter. 3. Recuperator. 4. Pocket channel fine filter. 5. Duct fans. 6. Heat exchanger for heating. 7. Heat exchanger for cooling. 8. Thermal sensor. 9. Humidity sensor

Supply and exhaust ventilation with recuperation and preliminary air preparation can act not only as air heating. The heat exchanger, which is part of the preparation complex, can be used for both heating and cooling. So one set of equipment, a set of air ducts, controls and settings will provide year-round control of the microclimate in the house..

The main advantage of air heating with recuperation and forced air circulation is the most complete automation of the process. The intake of fresh air can be controlled by a carbon dioxide sensor or, to ensure the required air exchange rate, valves and gate valves with servo drives are used. One controller controls the fans, humidification and dehumidification unit, heat generator operation. The user can set the heating or cooling mode, the activity of the system according to the schedule or even in fully automatic mode, based on the readings of the humidity, temperature and air composition sensors.

Fresh air inlet with duct fan and servo-controlled damper

The specifics of self-installation

Today there are many companies that are ready to develop and implement air heating at the facility. However, it can be built on your own. The whole process begins with the selection of key equipment – a heat source, heat exchangers and a set of components for ducting. A gas heat generator will successfully cope with the role of a source. To determine the choice of a specific device, it is necessary to take into account the upcoming consumption of fuel resources, as well as the area of ​​the house or room.

A gas boiler is effectively used as a heat generator, but a solid fuel boiler of the Buleryan type, harmoniously integrated into the interior of the house, will look much more effective and practical.

I must say that one cannot do without a scheme and carrying out detailed calculations. The slightest mistake can lead to damage to the heater, drafts and noise from operating units. It is important to select the cross-sections of the ducts so that the air is distributed evenly and without distortions between individual branches and channels. The volume and frequency of air exchange, the ratio of recirculation with supply and exhaust are calculated.

The following can be used as air ducts:

• galvanized steel square or round ducts;
• flexible corrugated air ducts;
• PVC pipes.

To minimize heat loss, the air ducts are equipped with thermal insulation, which simultaneously reduces the noise level both from the operation of the heating system components and the distribution of sound between rooms.

1. Round section galvanized steel air duct. 2. Flexible corrugated duct with insulation 3. Rectangular duct. 4. Rigid duct with insulation. 5. Flexible duct

Set of air ducts and connectors made of polyvinyl chloride

Air ducts with grilles for air distribution or full-fledged indoor units are installed in each room, with which you can set an individual heating mode. It is optimal if all the design and installation of the system is carried out at the stage of building the house. In this case, the air ducts can be placed in special niches in the walls. But if the house has already been built, then for the air ducts you will have to build false walls, suspended ceilings or other structures that hide the elements.

The cost

The final cost of the finished system is individual for each house, because the calculations must take into account the area of ​​the heated room, the model and power of the heating equipment, the total length of the air ducts, their number and throughput, the cost of payment for installation and commissioning of equipment, if this is done by a third-party organization.

Companies providing services for the organization of air heating, when calculating the cost, take into account the following items of expenses:

1. Design cost.
2. Costs for the purchase of equipment, components and additional devices.
3. The cost of professional editing and customization.

Average price of turnkey air heating installation in a house up to 100 m2? is 3500-4500 rubles per 1 m?.