Constant air velocity (CA) air curtain

Depending on changing weather conditions an air curtain needs less or more heat to condition cold outside air entering the building. For example in winter, air curtains are often set at a higher speed to discharge more heated air at a higher air speed. However, the higher air velocity produces considerable turbulence, and a lot of heated inside air escapes to the outside.

To solve these problems Biddle developed CA-technology, which varies the air discharge opening depending on weather conditions.

Low fan speed, low air velocity, damper is half open.	Highest fan speed,  damper opens, air velocity remains constantly low.

CA technology comprises an intelligent damper system which automatically increases or decreases the outlet grille width whenever the fans are switched to a higher or lower speed. This keeps the discharge velocity constant, whilst increasing or decreasing the air volume and heat output. The higher the fan speed the wider the grille. The increased air volume consequently carries more heat whilst maintaining the optimum discharge velocity and ideal outlet temperature of 35°C.

As soon as the air curtain is set at a higher fan speed, the discharge width will increase, allowing the wider air stream to produce more heat at the same constant air velocity and low noise level.

• The wider air stream means a better downward penetration
• The air stream is hardly perceptible. 
•  More entering cold air is heated up 
•  Result: optimal comfort and efficiency