Each of us who visited a shopping mall at least once passed through an air curtain. These devices are essential equipment for shops, retail chains, or service premises. Air curtains allow you to reduce draughts and heat or cold losses – depending on the season – caused by opening the exterior door. How air curtains work and what solutions can be found on the market – a handful of practical tips are presented below.
The difference in air temperatures between the two sides of the entrance door makes the heated or cooled air escape to the outside irretrievably when the door is opened – this generates a large amount of energy loss that needs to be covered by heating or cooling the room. The use of a vestibule can solve this problem, but due to the small size of the space, it is not always possible – the reason for this is the limited usable space of such premises. In accordance with good practice and current legislation, alternatives to vestibules are air curtains. They create a strong stream of air, directed in parallel and tangential planes to the door opening, preventing draughts and heat losses in winter and the ingress of warm air into cooled and air-conditioned rooms in summer.
Operating Principle of Air Curtains
Market presence air curtains are mostly compact devices, installed directly above the exterior door. Manufacturers offer compact air curtains in several versions, e.g., in an economical, standard or elegant design. The air curtain is composed of a supply grille, an exhaust grille, and a fan. Additional equipment of such a device is an electric or water heater. The air curtain generates an intensive air stream from the slotted discharge grille. The air stream flows through the fins at an angle and is pumped through the fan, which is usually located in the air curtain housing and heated. This creates a strong, flat-shaped stream of air that forms an air barrier that blocks the inflow of outside air through the open door. Air curtains with a heater are used in small shops and commercial premises, as they do not require heating in the form of radiators that take up valuable space.
Air Curtains – What Does the Market Offer?
There are various curtain solutions available on the market, tailored to the needs of the building. The air curtains can be divided according to the temperature of the supply air – warm and cold. In the passageways and doors used by people, warm curtains are used. In places less frequented by people, e.g., gates for driveways, we use cold curtains. In terms of construction, we distinguish curtains with a single or double air stream. For industrial applications, curtains with horizontal air streams (e.g., for vehicle doors in industrial plants) are used.
Housing air curtains are usually made of galvanized steel sheet, powder-coated. Lengths of air curtains are varied; standard lengths are 1500, 2000 and 2500 mm. The range of the air curtains is 2.5-4.2 m – depending on the selected model and conditions. An optimally selected air curtain should produce a dynamic air stream which constitutes an effective barrier against the penetration of cold or warm air into the interior of the building in the entire light of the entrance opening. In such cases, the use of air curtains can reduce heat loss by up to 80%.
The use of air curtains in cold stores additionally eliminates the phenomenon of door freezing and eliminates the formation of mist – when humid air is mixed with internal air. The installation of air curtains is worth considering wherever the door is open permanently or very often. Air curtains are also used in restaurants to separate smoking and non-smoking areas. Such devices can also significantly reduce heating or air conditioning costs, depending on the season, and provide comfort to people living in the building.