The supply system that mixes the air in the room is called supply ventilation. The combined devices simultaneously heat up the streams. In buildings, natural and forced air supply is distinguished. The first type is carried out due to the pressure difference between the flows, and in the second case, fans and other units are installed.
The need for effective ventilation
Supply and exhaust ventilation differs from air conditioning in that it uses outside air from the street. Stale air has a negative effect on health and emotional well-being, so care must be taken to provide a fresh atmosphere. Waste masses are removed by means of a duct exhaust.
In a room where people are constantly present, the required air exchange is 30 m3 / h per person, and in the absence of it, a standby conversion is recommended. For an apartment with 4 residents, ventilation should change the air at the rate of 120 m3 / h, and in the absence of people - 40 m3 / h.
Window blocks made of metal-plastic with double-glazed windows supply air at a level of 2 - 5 m3 / h and do not even provide standby ventilation, despite the built-in micro-ventilation, self-ventilation and air conditioning devices. The release of harmful substances, which saturates the microclimate from furniture, modern finishes, matters. In such conditions, an organized supply ventilation unit is required.
Advantages and disadvantages
Ventilation in the apartment is organized compactly, special technologies help to reduce the noise level. Modern installations meet the increased requirements for the purification and filtration of air masses. Enclosures and air ducts have a pleasant appearance and can be hidden from view behind a suspended ceiling or decorative wall elements.
Positive aspects of using a supply and exhaust ventilation system:
- ensuring the need for air exchange;
- the branching of the circuit with the given characteristics of work in each room;
- the possibility of using heated waste streams to increase the temperature of the incoming air (recuperation).
Ventilation in private homes supplies air to all functional areas. The control is carried out in an automated way and allows you to set the feed rate in different rooms, as well as adjust the degree of heating.
Supply ventilation has a number of disadvantages:
- it is difficult to mount in an exploited building, there is not always a place;
- the use of noise insulation will take up even more useful space;
- the force feed device requires material costs.
Street air masses are cold in winter, so heating is required. To clean the streams from dust and elementary particles, you need to install separate filters or a disinfection system.
Main goals
The air handling unit filters the air and delivers the cleaned volumes to the pipeline for subsequent distribution to the rooms.Cooling of streams is organized in warm time, and heating in winter. The circuit includes a water filter, a charcoal filter and electric heaters. The speed of the flows is given by means of fans, the control is carried out by automatic equipment. Insulation material is used to protect against cold and noise. If the supply system is equipped with an air cooler, it is called a central air conditioner.
Ventsystem provides:
- supply of the required volume of air from the outside;
- regular updating of the microclimate, and not just individual episodes;
- lack of sharp streams and drafts;
- reduction of dust, number of insects, noise.
Supply ventilation does not solve such issues as maintaining the required humidity and temperature of the interior space.
Supply ventilation classification
The general ventilation system supplies air to all rooms of the building; this scheme is used in industrial volumes. Harmful substances in the production process are distributed throughout the workshop, and there is no way to capture them locally. Air enters the work area (1.5 - 2.2 m from floor level). A local air handling unit supplies air to specific areas or rooms.
By the presence or absence of air ducts
In a ducted system, air flows move through pipelines of a certain section. Risers and mines in the walls are performed during construction or when rebuilding a task. Through them, the inflow and removal of air can be carried out simultaneously.
The hinged pipeline is located under the ceiling. It includes a central unit for processing air masses, for example, disinfection, filtration, heating or cooling. For the location of such a pipeline, space is needed, therefore, channel systems are almost never installed in city apartments with a wall height of 2.45 - 2.6 meters. Duct circuits are used in public places where there is a large crowd of people.
Channelless supply ventilation in an apartment involves the installation of a forced turbine in a wall fence or floor slab, while the flow is supplied to one room.
By design
The supply ventilation chamber attracts consumers by the fact that it is combined with specialized equipment to change the properties and characteristics of the microclimate. During air injection, it can be heated and cleaned.
The functional diagram is performed in two designs:
- Monoblock. It includes one module where the necessary devices are placed for high-quality and uninterrupted operation of the ventilation unit. The location is usually an outer wall or window frame. It does not differ in efficiency of work, since due to the limited location of the fans, the entire area of the apartment is not covered.
- The branched network contains several injection units as part of a common line with the use of different types of hoods and pipes that supply fresh air to all rooms and service areas of an apartment or house.
The system is pressurized by an external turbine module and the inlet is located in a residential area where clean air is needed. Installation of a supply ventilation unit is not allowed in the area of a bathroom, bath or kitchen.
By ventilation method
Most apartment buildings use natural ventilation. This provides for the flow of air without coercion, the movement occurs due to the difference in the pressure of the outside and inside air and changes in temperatures. Streams enter the apartment on their own through the cracks in the window and doorways. Waste masses are removed by means of a ventilation shaft, which has a branched structure.
The natural system belongs to the available species and does not require investment.The disadvantage is that there are regular interruptions due to insufficient supply of fresh air. Opening the openings partially solves the problem, but in winter the cold inflow reduces the comfort in the room, and noise penetrates the windows.
The forced air purification system for the apartment provides a stable flow of oxygen, which does not depend on the weather. The air is supplied by the fan blades, the automation regulates the intake rate, adapts it to the existing air exchange needs. The system does not require human intervention, which makes it convenient.
Equipment Models
The ventilator is mounted in an external wall and supplies fresh air through the duct by means of a ventilator. The inlet valve enhances the natural flow, its functioning is determined by the weather outside the window. In summer, due to the small difference in temperature outside and inside, such a device shows little efficiency.
The breather combines ventilation and filtration of air masses. The compact device is installed in the wall and is able to ventilate a room up to 50 m2. The device has one or more filters that are regularly replaced with new ones. Its use is relevant in homes near gas-polluted highways or near industrial complexes.
Fans are either axial or radial. The first type captures the flow with blades and moves it along the central axis, while there is no radial distribution. Diametrical turbines change the direction of the air and are used for low resistances in the ventilation system.
Noise mufflers reduce the aerodynamic sound of streams; by design, there are plate and tubular types. They feature a large curved area of insulating surfaces against which vibration and noise are damped. Installed between the fan and the beginning of the pipeline.
How to optimize supply ventilation
Air purifiers are used to filter the supply air. The principle of their operation, material and design are selected depending on the required characteristics of the microclimate. In ventilation systems, filters are divided according to the degree of purification, there are five of them in total. The smaller particles are retained by the membrane, the higher the class of the purifier. The filters are characterized by dust holding and aerodynamic resistance.
Ventilation can work in contact with the heating system or replace it in some cases. The units use electric or water heating elements. The first type works from the mains and converts energy into heat. Water elements are energy exchange chambers where a heated liquid transfers heat to the air.
Air recovery
The technology consists in reusing heat using recuperators. The procedure is performed in heat exchangers, where the heated removed stream transfers heat to the incoming cold mass. The process saves money for heating the tributaries by reusing the energy of the outgoing masses, for the creation of which money has already been spent.
Heat exchangers are of two types:
- Cross-type plate recuperator. In the unit, supply and exhaust air do not mix, but pass through numerous ducts with common walls. The efficiency reaches 70 - 85%.
- Rotary recuperator. The exchange of energy is faster than in the previous form, while the supplied and removed streams are partially mixed. The efficiency is equal to the values of the cross plate device.
There is a recuperator with an intermediate exchange chamber. The inflow and the extracted mass are distributed in space, and the heat between the channels is transferred through the movement of the liquid energy carrier between the individual chambers. The efficiency is 50 - 60%, but this application is justified if the extracted air is hot and too dirty to mix.
Ground heat exchangers
A geothermal heat pump is used to heat the supply flow in the supply ventilation. It is a heating system that uses the warmth of the earth's interior in the geothermal zones of the planet. The temperature difference helps to increase functionality and reduce costs. Geothermal pumps often work in conjunction with solar heating.
Closed geothermal heat systems are divided into types:
- Horizontal, when the collector is located at a shallow depth below the freezing mark of the soil, pipes are placed in a sinuous manner. The layout requires a large area.
- Vertical, if the pipeline is installed standing to a depth of 200 m. This option is used when the house is located in a small area or there is a risk of surface damage, for example, from landslides.
- Water type. Pipes are located in bends or in an annular way in the thickness of the reservoir below the freezing mark. A cheap method, but there are certain restrictions on the choice of a reservoir.
Open systems use the fluid flowing through the ground source heat pump system in an open circuit for heat exchange. This is a re-circulation after passing through the main line when returning to the soil. The option is implemented in the presence of a large volume of clean water and an official permit for the use of land waters.
