Indoor climate protection
First of all, air curtains are designed to prevent outside air from entering through open doorways into a certain climatic zone (with heating or cooling). Air curtains reduce energy costs by keeping warm or cool indoor air.
Efficient air curtains will save up to 80% of energy losses through a doorway compared to a door without an air curtain.
In winter, the air curtain creates a barrier that keeps out cold air, and in summer, the airflow protects hot air from outside.
Considering energy savings, the average payback period for an air curtain is between 2 and 5 years, depending on usage and climatic conditions.
Although the doors are open, the air curtain separates the indoor and outdoor conditions
Pest and flying insect control
Air curtains protect your premises from insects. They will be stopped by an air barrier too powerful to penetrate. In catering establishments, bars, restaurants, cafes - this is extremely necessary. Especially it should be noted that air curtains are needed in healthcare facilities. Hospitals, hospitals, dentistry, etc. the presence of insects is not allowed in them.
Air curtain stops outside flying insects from entering
You must choose the right air curtain to cut off the insects. A powerful air jet is needed along the entire doorway (stronger than standard).
Air curtain in cold rooms
Due to the large temperature difference, it is highly recommended to install air curtains to reduce energy loss when the door is open. The higher the temperature difference between the inside and outside, the higher the energy loss if the door is not secured. So the payback period of the air curtain is very short and then the energy/money savings are very high. Not only will we save money by keeping air out of the door, but we will also keep frozen goods in perfect condition and help reduce the cost of defrosting the refrigerator compartment.
Air curtains are the safest way to save a lot of energy in cold rooms
For cold rooms and freezers, air curtains are the safest way to protect against energy loss without any physical barrier that can lead to accidents or collisions on the doors. For example, when plastic strip curtains are used, the view through the doorway is limited and accidents to people or vehicles occur. In addition, it prevents annoying and potentially dangerous fogging, moisture and ice formation in the door entry area.
Air curtains can be installed in all places where doors are frequently opened.
Installation method and choice of curtains
Requirements for the organization of curtains are formulated in SNiP 41-01-2003 "Heating, ventilation and air conditioning", section 7.7. Most air curtains are designed for horizontal installation above a door or window opening. At the same time, the curtain itself is located horizontally and the flow of air coming out of it is directed downwards. Such a curtain is called horizontal.
Sometimes such installation is impossible or impractical, for example, if the opening height is very high or if the doors open vertically upwards. In such cases, vertical thermal curtains are used, which are installed on the side of the opening. The air flow will then be directed horizontally. The height (length) of the vertical curtain must be at least 3/4 of the height of the protected opening; in all other respects, the curtain does not differ from the horizontal one.
By design, air curtains are divided into built-in and outdoor versions. Built-in thermal air curtains are designed for installation in a false ceiling or a duct, while outdoor air curtains are simply mounted above a serviced doorway.
It is very important to correctly determine the type of air curtain you need. The determining factors here are the width of the doorway, the height of the installation and the speed of the air flow.
Experts suggest applying the following simple tips:
the higher the opening, the greater should be the speed of the air flow leaving the curtain;
the air curtain should cover the entire doorway in width, so its length should not be less than the width of the opening, and should be located as close to the opening as possible. The air flow rate generated by the horizontal air curtain must be large enough to reach the floor
In this case, the flow should be directed vertically or slightly inclined towards the room with cold or polluted air;
in large openings, it is necessary to install several air curtains in one line and close to one another, creating a continuous air flow;
in rooms with a large internal volume and several entrances and exits, it is necessary to take into account the influence of wind force on drafts that occur in the building;
it is important to choose the right flow rate. A low-power air curtain does not block the height of the opening, and a too powerful flow leads to leakage of warm air;
a necessary condition for the normal operation of the air curtain is that the speed of the air flow leaving the curtain at the floor level must be at least 2.7 m/s.
With the same dimensions, the thermal power of curtains can be different and is selected from the following considerations:
- the need for additional or main heating of the room (tambour);
- air curtain installation location and mode of operation of the doorway (location at the door opening to the street, in the vestibule or from the side of the heated room, door opening frequency). So, when working on an open opening, from 50 to 70% of the power of the thermal curtain can be lost;
- availability of a source of electricity (or hot water) of the required capacity at the facility. Closely related to the thermal power is such an operating parameter of the air curtain as an increase in air temperature when passing through the heating elements. The higher the temperature rise, the shorter the time during which the air curtain heats up a given volume of air. For curtains with electric heating, the temperature rise is from 8 to 35 °C, for water curtains - up to 40 ... 50 °C.
When determining the cost of installing curtains, the following points should be taken into account. First of all, the object should be inspected and measured to the extent necessary, and this service is provided to the customer free of charge. The cost of installation is minimal when the air curtain is attached to a solid monolithic wall and special fasteners are not required, and a power cable of the required cross section is brought to the installation site. The cost of installation increases when it is necessary to lay a power cable from the curtain to the electrical panel, lay the cable in a strobe or box, fasten the curtain on special metal structures - wells, angles, brackets, hangers, which sometimes need to be made.
The editors would like to thank the company "Soglasie" for their help in preparing this article.
Why you need to install an air curtain Advantages of installation and absence
We classify the advantages of air curtains into 4 groups:
Commercial yield
- Increasing sales through the "open door effect". It is known that when the doors are open, the desire of people to enter the door increases significantly.
- Open doors are an invitation to customers
- The doorway acts as a store window and allows people to see the inside of the store
- Free access for the disabled (wheelchairs) or people using prams, trolleys, umbrellas, etc.
- Draft control
- Increases available usable space at inputs
- Increases customer and staff comfort
- Helps maintain an adequate environment
- Reduces employee absenteeism
- Pest and insect control
- Barrier against airborne dust, pollution, fumes and odors
- Reduces energy losses in air conditioning
- Reduce the consumption of thermal energy during the cold season
- Reduces the cost of running a building
- Reduces CO 2 emissions
- Increases visibility of the entrance counteracts collisions between people and vehicles
- In cold rooms, it reduces fogging, dries out the doorway and prevents the formation of ice on the floors.
- Easy evacuation through exit doorway in case of fire or emergency
- Act as a smoke barrier against fire (special application)
To achieve these benefits, it is necessary to choose the right air curtain.
Inefficient air curtain (loss of money) Efficient air curtain (money saving + benefits)
If the seller chooses the wrong air curtain for you, then the air jet will not reach the floor, and the separation of two adjacent areas will not be achieved. Then all the heated/cooled air will cross the doorway and you will lose energy and all other benefits.
Some people only care about the price of the air curtain and choose a less efficient or inadequate air curtain, sometimes following the recommendations of other sellers. To be sure, you should always compare the characteristics of the air curtain, especially the type of fans used and the air volume. The thermal curtain must be chosen so that it saves you money and creates comfort. In conclusion, the use of an air curtain on open doors is highly recommended due to the many benefits.
Calculation of air and air-thermal curtains
Outside air enters the room through gates and other openings in the walls of the building due to the difference in pressure outside and inside the building. The amount of air supplied by the air curtain must completely exclude the penetration of cold outside air. When starting to calculate and design air curtains, first of all, the initial data are determined: the size of the gate, the amount of outside air that passes into the room through the opening without the curtain working, the estimated temperatures of the outside and inside air. The main parameters determined by the calculation are the air capacity of the air curtain, the angle and speed of the air supply depending on the size of the opening, the power of the air heater for heating the air.
Currently, there are several methods for calculating industrial air curtains. Below is an approximate method. It is rather conditional, since the value of the jet range (the distance between the points of intersection of the curtain axis with the plane of the gate) is calculated geometrically, and is based on the use of a range factor that depends on the angle of inclination and the turbulence coefficient of the curtain jet and is determined on the basis of calculation and experimental data for the case of a uniform distribution of horizontal flow velocities.
The amount of air entering per unit of time, or flow rate, m3 / s, through any open opening,
where v is the air velocity, m/s; H and B are the height and width of the opening, respectively, m.
Air consumption, m3/s, necessary to create a curtain in the opening, which completely excludes the breakthrough of cold outside air into the warehouse,
where φ is the coefficient of the air flow range of the curtain, which can be taken equal to 0.45; b is the width of the channel slot through which air enters the curtain, m.
Thermal power of the heater, kcal/h,
where th – air temperature of the curtain jet, °С; tearly - normalized (or outside) temperature depending on the place of air intake, ° С.
A more accurate method for calculating air curtains is based on the use of a conditional air flow rate, which is defined as the ratio of the amount of air supplied to the curtain to the amount of air passing through the gate. It is fully described in the works of V.M. Elterman "Air curtains" and "Guidelines for the calculation of air curtains".
Control and regulation of air curtains
Air curtain control is necessary to prevent excess energy use by changing the characteristics of the air curtain according to each situation.
By using appropriate controls together with auxiliary devices, the customer can adjust the air flow, temperature, to optimize the performance of the air curtain and avoid air intrusion through the doorway.
The basic controllers allow you to change the ventilation speed and heating levels manually.
- Automatic operation: changing ventilation and / or heating depending on the task
- Connection to external sensors and/or devices
- Enable internal sensors (temperature, motion, etc.)
- Interface connection with automation systems, external on/off, thermostatic control
- Internal security programs (protecting components and avoiding damage)
- Door contact, valves, heating medium sensors, etc.
Door contact (magnetic, mechanical) Solenoid valve Frost sensor
For example, if we install a door contact connected to the air curtain, when the door remains closed, the air curtain is switched off or running at a low ventilation speed and/or a lower heating level, which saves energy. When the door is opened, the air curtain increases the ventilation speed and/or heating level to protect the doorway.
Another example is connecting an air curtain to a room thermostat. The device will then increase/decrease or stop heating when it reaches the desired temperature.
Techcold has a wide range of controllers from standard manual to advanced automatic functions and an interface for connecting air curtains to automation systems.
In addition, we offer a wide range of accessories: various supports, room thermostats, door contacts, solenoid valves, antifreeze sensors, etc.
What is an air curtain
An air curtain is a fan-assisted device that creates an invisible air barrier over a doorway to effectively separate two different environments without restricting access to people or vehicles. Accordingly, a thermal air curtain is all of the above also with heating. The energy-saving air shield reduces heating and cooling costs by up to 80%, protecting the indoor climate and improving people's comfort. It keeps the atmosphere clean from pests and insects, dust, air, pollution, odors, prevents drafts and cold or warm air from entering the room.
The functioning of the air curtain is based on a high-speed air jet that closes all openings. Heated air curtains create comfort with a jet of air as people cross the air curtain and help maintain inlet temperatures.
Air curtain technology
It is known that in open doorways with two adjacent areas under different conditions, the air between them is interchangeable, because the laws of physics tend to equalize the difference in temperature and pressure between both sides. Basically air transfer in doors is due to these 3 factors:
Temperature Difference: This is the natural convection effect that creates an air transfer between two areas with a temperature difference.Warm air will exit through the top of the doorway and be replaced by cold air entering from below. The greater the temperature difference, the greater the air exchange and energy loss.
Pressure difference: it is recommended to balance the pressure difference as much as possible, as it affects the performance of the air curtain. But in some installations, such as clean zones, a small pressure difference helps to prevent particles from entering from outside.
Natural wind and drafts: By changing the force of the air jet and outlet angle, the air curtain can counteract forced air movements such as natural wind or drafts. If the incoming air velocity is excessive, the air curtain will become less effective.
Schematic representation of the main parameters related to the performance of an air curtain. The efficiency of an air curtain depends on the optimization of performance factors.
The most important of them:
Jet turbulence: a jet with low turbulence will be much more efficient and save energy. Air speed: air velocity must be sufficient throughout the entire doorway. Air volume: a wider jet makes the air curtain stronger against air movement in doorways. Corner Throw: depending on the situation, if the nozzles are well oriented, it will increase the energy saving. Fan type: axial, tangential, centrifugal, etc. Higher pressure fans produce a higher pressure jet that is more efficient. For example, if we compare an air curtain with a tangential air curtain fan with a centrifugal fan (with the same air volume), the jet from the centrifugal fans will be stronger and larger.
Research shows that air turbulence is one of the most important parameters that affect air throw distance.
The optimized shape of the outlet chamber, the position and type of fans, the shape of the lamellas, etc. significantly affect the performance of the air jet.
Inclined jet at the air curtain.
Tests and university studies have proven that angular discharge can significantly improve the efficiency of an air curtain. When factors such as wind, temperature, or pressure difference cause air to move from outside to inside, we can direct the jet outward to some extent. Then directing the jet against the air inlet will help keep the air out. The trajectory of the jet will be parabolic, but at the end it will reach the floor close to the doorway. If we cannot adjust the throw angle, the jet will be pushed out by the forces of the outside air. Fixed vanes, where the velocity of the incoming air pushes the air curtain jet, the resulting parallelogram of forces deflects inward. This allows outside air to enter inside. Adjustable slats when the air jet is oriented against the inlet. This means that no outside air enters and no inside air comes out. In addition, the internal temperature level is maintained.
Air curtains with heat pump
Heat pump technology
A heat pump is a device that uses a small amount of energy to move heat from one place to another. This system is extremely efficient because it simply transfers heat rather than burning fuel to create it.
It consists of a closed circuit through which a special liquid (refrigerant) flows. This liquid turns into a liquid or gaseous state depending on temperature and pressure.
The circuit consists of: compressor, condenser, expansion valve and evaporator
Advantages and Benefits
Air curtains on a heat pump are very efficient at 1kW of electricity consumption, 4kW output
- Very high energy efficiency ratings.
- Short payback period due to very high energy savings
- Heating and cooling included in the same system (reverse cycle)
- Environmentally friendly as it uses such a low amount of energy
Are air curtains effective?
Absolutely effective!
All studies and tests have proven that air curtains are effective. When an efficient air curtain is properly installed, it saves a lot of energy, while at the same time the entrance areas remain weatherproof, comfortable and free from drafts, insects, odors, etc. The diagrams below clearly show the effectiveness of air curtains. The surface of the following diagram is divided into two parts (at X = 2): the left side viewed inside has a heater on the wall, while the right side with cooling simulates the street
Option without air curtain:
Following the laws of physics, light heated air to the left of the image rises by natural convection and to the side, while heavier unheated cold air enters from the outside, passing through the floor. Since the air tends to equalize temperature and pressure, and the heat inside is not protected from external influences, the air mixes and we cannot heat the right side. In this situation, we waste a lot of energy and the heater cannot maintain a comfortable internal temperature.
Air curtain option:
The air jet of the curtain, located on top, clearly separates the warm and cold zones into two thermal zones. The air curtain keeps the interior environment on the left side of the image at a comfortable warm temperature and prevents cold air from entering from outside. In this second situation, the air curtain saves up to 80% of the energy generated by the heater located on the left wall.
Important note: Poorly designed air curtains, improperly selected type and size or performance, or not professionally installed will lose some or even all of the benefits and may be worse than an unsecured door.
Installation of air curtains
A team of professionals from Techholoda LLC will quickly, on time, and efficiently select and install thermal air curtains. We will install thermal air curtains from such manufacturers as Ballu, Dantex, Frico, General, Climate, Hintek, Hyundai, Kalashnikov, Loriot, Neoclima, Olefini, Sinbo, Sonnige, Termica, Timberk, Tropik Line, WING, Zilon, Antares, Teplomash, for openings up to 12 meters high.
When protecting the opening, it is necessary to take into account the main characteristic, the height and width of the opening. The larger these dimensions, the more heat output will be required. When selecting, the average air temperature in the opening is calculated, drafts, cardinal points are calculated, if necessary, hydraulic piping, electrical connections, load-bearing structures and other parameters are designed.
Air curtains can be installed horizontally above the opening, vertically on one side of the opening or vertically on both sides of the opening.
IMPORTANT TO UNDERSTAND! It is necessary to cover the entire opening with heated air.
- Installation of an air thermal curtain at a height of up to 3 meters on a concrete or brick base
- Connecting the air curtain to an existing power and protection circuit breaker or power socket (the circuit breaker or socket must be installed by the customer) or is this additional work
- Checking and commissioning
The cost of a standard installation of a thermal curtain is 3200 rubles.
|
Name of works |
Price, rubles |
| Installation of an air curtain up to 1 meter long, installation height up to 3 m, without power supply |
3200 |
| Installation of an air curtain with a length of 1 to 1.5 meters, installation height up to 3 m, without power supply |
3500 |
| Installation of an air curtain with a length of 1.5 to 1.8 meters, installation height up to 3 m, without power supply |
4200 |
| Installation of an air curtain with a length of 1.8 to 2.0 meters, installation height up to 3 m, without power supply |
4500 |
| Installation of an infrared panel heater, without power supply |
3300 |
Additional work on the installation of an air thermal curtain is paid separately.
Standard installation of the air curtain is carried out using the brackets included in the kit. When the installation of air curtains is complicated by the structural features of the building or opening, Tekhholod will produce special load-bearing metal structures.
Contact the consultants of the Tekhholod company, we will select the right thermal curtain and reduce your costs! https://techholod.com/ tel +7 495 966-41-42 or send a request to info@techholod.com
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