How the air curtain works?

Maintaining stable temperature inside the building is important for user comfort. Both in summer and winter, the differences between the interior and the surroundings of the facility are significant. Frequent movement related to opening and closing doors results in mixing of air from both zones and resulting in a change in the interior temperature. The solution to this problem are air curtains.

What are air curtains?

Facilities such as shops, public offices, service points such as photocopying or catering premises located at moving streets are often visited by customers. Continuous opening and closing of doors in winter causes cold air to flow in. As a result, the interior is cooled down and much more energy is needed to heat it. Air curtains installed in the immediate vicinity, above or side to, of the entrance door create an invisible barrier to the atmosphere and particulate matter. As a result, air exchange does not take place and pollution does not enter the interior.

Air curtains are devices producing an air stream of a specific width. This allows them to be adapted to the dimensions of the passage and to ensure tightness of the curtain. 

How does the air curtain work?

The air curtain is a relatively simple design and operating principle. Inside the curtain, there is a fan and as an option the heat exchanger (water or electrical). The fan operates using circulation air, generating a specific blowing force. Another important parameter of such a device is the maximum airflow capacity, which determines the strength of the barrier. The higher that value, the more particles the curtain stops. It is also effective in locations where the entrance is exposed to strong gusts of wind.

Air curtains are divided into the following categories: 

• equipped with electric heating coils,
• cold curtains (without heating elements)
• equipped with water heat exchangers

They may cooperate with the heater or with the building’s central heating system. This depends on whether the device is equipped with an electrical or water exchanger. In the first case, it requires access to the power supply, in the second case - connection to the hydraulic network system. 

Why air curtain?

As mentioned above, the main function of the air curtain is to create a physical barrier between the interior and the exterior of the building. As a result, air does not penetrate the other side. The aim of such a solution is primarily to prevent cold and warm air mixing. This is particularly important in winter when the outdoor and indoor temperatures differ by up to 30–35°C.

In fact, the device has more several more functions – the barrier they create also stops physical pollutants. The curtain works not only in winter, but also in the summer. It limits movement of hot air from the outside. Thanks to that, the door doesn’t have to be closed, the air conditioning doesn’t have to be turned up, and there is no need to use additional fans. Moreover, the retention of sand and dust with wind makes the entrance room cleaner and easier to clean. An important function of the air curtain is to save thermal energy.

The air curtain also has a beneficial effect on the health of the people present indoors. An extended impact of low temperatures may contribute to people falling ill with the common cold and exacerbate symptoms of rheumatism. This impact is especially noticeable for people who work seated. Even more serious consequences may come about in result of drafts or exposition to frequent changes in ambient temperature. These are experienced by employees of small shops, reception desks, security rooms etc. 

Advantages air curtains

Knowing how the air curtain works and what functions it performs, it is also worth mentioning its greatest advantages. These are the most important ones:

• high efficiency in proper blowing force selection,
• easy operation and simple assembly,
• low failure rate,
• limiting heat loss,
• limiting the penetration of pollutants and insects into the interior,
• maintaining a constant indoor temperature,
• possibility of additional heating thanks to the equipped heater,
• possibility of connecting to air-conditioning or heating – control of the airflow direction,
• remote control of curtain functions.
  
  

Types of air curtains 

Air curtains differ in several elements. One of the most important is horizontal or vertical airflow. In the simplest devices, one option needs to be selected. More advanced devices such as the WING curtain series are adapted to both types of airflow, which significantly extends the scope of their applications. Two basic types of air curtains differ in the type of heat exchanger used. It may be:

• electrical – the device is equipped with a heater with appropriate power supplied with a single or three-phase current,
• water – the device is connected to the central heating system and the exchanger heats air from the supplied medium. 

What air curtain should you choose?

Air curtains are very widely used. They can be installed both in small public facilities and in greenhouses, warehouses, industrial halls, and logistics centres. It is clear that in any case other parameters of the device will be necessary. Therefore, the selection process for the curtain should start with the identification of specific needs.

Additional possibilities are created by adjusting the curtain for installation in pairs, threes, and other configurations. As a result, in the case of two-wing doors, each part may have its own protective barrier. For example, a WING air curtain is available in three sizes – 1 m, 1.5 m, 2 m. By combining several curtains, one can secure a passage both 2 m and 15 m wide.

The criteria for selecting air curtains are mainly the following: 

• doorway width,
• installation zone next to or above the door,
• usage intensity,
• temperature and pressure difference between the two zones. 

For industrial premises, the best choice are air curtains equipped with water heaters. It is also worth noting the level of noise generated. In the case of cold curtains, at a distance of 5 m from the device, it may be 53 and 63 dB (when operating at full capacity). This is important for smaller rooms, e.g. reception desks.