Vertical air curtains prevent inflow of cold outside air through doorways

In university buildings where thousands of people enter and exit every day, revolving doors are often in operation and even keep running for long periods of time. Warm indoor air thus disappears to the outside and cold outdoor air enters. Many people find it extremely disturbing when a bulk of cold air flows in through the doorway, and in order to catch the cold, extra heating must be used. An air curtain prevents that problem. That is why the specialists from HVAC Nederland were involved by main contractor BAM Techniek and Bouw in the Echo education building at TU Delft to produce and install three vertical air curtains. 

"We were involved in this project at an early stage to help think about the air curtains. Over the years we have built up a lot of knowledge and experience regarding the development, production and installation of appropriate air curtains for a wide variety of applications," says Frank Joosten of HVAC Netherlands. "Originally at BAM they were thinking of integrating air curtains that would blow out of the floor, but we are not in favor of that. We ended up proposing the Omnivent-VMR air curtain with the fan unit under the floor of the turnstile and a discharge lance, which blows vertically from the floor to the ceiling over the entire walk-through height."

A customized 'lance'

Each installation is unique and is tailor-made. Depending on the dimensions of the door and the required air volume, FlowMotion engineers calculate the shape of the so-called "lance. This is a long tube in which the air flows out over its entire length through the side. "Based on these calculations, we make the steel profiles for this 'lance.' In the new education building, for example, this tube runs from 160 x 160 mm to 45 by 50 mm over a length of 3,000 mm," Joosten explains. "We have already installed several dozen of this type of air curtains in the meantime. In appearance they are similar, but the construction is different each time."