Air curtain is an equipment with a blower fan that discharges high air flow capacity usually from the top to the bottom of an opening with different air temperature. It can also be installed sideway. Some manufacturers have equipment that are equipped with heater to heat up the air before being discharged.
The invisible curtains are usually installed at the entrances or exits of supermarkets, theaters, lounges, shopping malls, lobbies, exhibition halls, churches, shops, manufacturing floors or warehouses. Most of the time, these doorways are kept open all the time for operational purposes. It is also used as a way to separate the smoking and non-smoking areas.
Energy is conserved as these curtains help to keep the air conditioned space or heated space to be confined within the building. During hot weather, it creates a barrier that keeps the humid and hot environment outside the building from coming into the conditioned space. By doing this, the internal humidity and temperature of the space are maintained to the comfort level of the occupants.
Of course, the most efficient way to conserve energy is to close the doorways with the doors but sometimes this is not possible due to the frequent use of the doorways. Usually, the energy conserved over a period of 1-2 years is able to justify the installation cost of the equipment.
During winter, the conditioned warmer air in the building is prevented from escaping. This invisible air barrier helps to conserve the energy inside the building. Take note that this barrier will be affected if there is a draft caused by the ventilation or exhaust system inside the building.
Hence it is important to ensure that the pressure on both side of the curtains is maintained to be the same throughout the operations of the curtains. Some manufacturers also installed a heater into the unit to heat up the intake air before being discharged.
Two air curtains being placed at the entrance to an air-conditioned restaurant.
How It Works
We will take the example of an air curtain that is installed above a doorway. The air is drawn into the front of the intake grill after which it is forced into the air chamber by the blower fan. The air is then forced to flow down through the discharge nozzle. The height of the mounting can be from 2m to 5m.
The cfm of the airflow must be strong enough to reach the bottom of the floor to ensure its effectiveness in creating a barrier between the outdoor and indoor. The cfm of a typical unit can range from 340 cfm to 1100 cfm. It is also a good idea to check the sound level of the unit which may go up to 60dBA.
Depending on the size of your doorway, you can get air curtains with width starting from 3 feet. Make sure you measure your doorway width before deciding which model to purchase.
Apart from creating a air barrier to prevent energy losses from the building, it also helps to keep flying insects from entering the building. Insects or bugs that try to enter the building will be stopped by the barrier created by the air velocity.
In areas where exhaust gas is prevalent, having this flow of high speed air will help to ensure that the unhealthy gas does not go into the building. Foul odor and smoke are other contaminants that you will want to keep them away from entering the building.
Dust is also prevented from entering the space especially in manufacturing floors that are sensitive to the airborne particles. Other than that, it also helps to maintain the humidity of the space by keeping the outside humid air from entering the building.