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Air curtain is a fan-powered device that creates an invisible air barrier over the doorway to efficiently separate two different environments, without limiting the access of people or vehicles.
The Rosenberg Group
Since its foundation in 1981 by Karl Rosenberg the Rosenberg Ventilatoren GmbH has emerged through its development and production of adjustable external rotor motors, fans, air handling units and control technology to an important center for Europe for the ventilation and air conditioning industry. Customer-oriented and highquality production is our top priority. The continuous information flow and a good cooperation between customers and our employees is very important to us to ensure quality and product enhancements. Modern performance testing, computer-controlled production machines and selfdirected work groups are also included as well as the integration of measures for higher quality and environment protection. The export share of Rosenberg lies currently at 60% of the total turnover. At the headquarters in Künzelsau the employees are 240, worldwide more than 1.400. Further Rosenberg production plants are located in Glaubitz (Germany), Waldmünchen (Germany), Hungary, Czech Republic, Italy, France, Slovakia, Turkey, Mexico and in China.
Airtècnics: The Air Curtain
SpecialistFounded in 1986 and placed in Castellar del Vallès (Barcelona), Airtècnics has a large experience producing air curtains. The technical department of Airtècnics works together with the Polytechníc University of Catalonia (UPC) to incorporate to our air curtains the latest technology. The university works with numerical analysis like the CFD – Computational Fluid Dynamics (see page 4), in order to simulate the behavior of the air curtains. Then, the results of the simulation are compared with the results that are obtained from the test stand at the university to estimate how accurate the simulation is. That way the UPC can simulate different scenarios, so that Airtècnics improves its air curtains. The Airtècnics staff, consisting of industry experts, pay great attention to development and quality.
What is an Air Curtain?
An air curtain is a fan-powered device that creates an invisible air barrier over the doorway to efficiently separate two different environments, without limiting the access of people or vehicles.
The function of an air curtain is based on a high velocity jet of air that covers the entire opening. The air curtains with heating make the jet of air more comfortable when people cross the air screen and helps to maintain the desired temperature at the entrance. Therefore the Rosenberg air curtains increase the comfort for staff and customers and reduce the heating and cooling costs by up to 80%. By using an air curtain, shops can leave the door open and the customers can have a full view of shop interior.
The end result are more customers and an increase in sales.
SCHÜTZEN VOR / PROTECT FROM:
• Kälte im Winter / Cold temperatures in winter
• Hitze im Sommer / Hot summer temperatures
• Autoabgasen / Car fumes
• Staub / Dust
• Verschmutzung / Pollution
• schlechten Gerüchen / Bad smells and odours
• Insekten / Insects
Selection of the right air curtain
For the correct selection of an air curtain please pay attention to:
• The installation height measured from the outlet nozzle to the floor
• The width of the door
• Weather conditions
• If the building has more doors which could create draughts
• Chimney effect in the building
• Pressure differences between the inside and the outside of the building
• Type of doorway: without door, automatic or normal door, revolving door, etc.
• Type of ventilation and air conditioning
• Availability of energy supply (e.g., power supply, warm water)
• Type of business, style and decoration of the premises
Please consider that the discharge angle of the air jet, substantially influences the overall efficiency of the air curtain.
Are Air Curtains effective? Absolutely!
The following advanced Computational Fluid Dynamics CFD diagrams made by the UPC (Polytechnic University of Catalunya) show clearly the efficiency of air curtains. The surface of the next diagram is divided in two parts (at X=2): the left side can be considered the inside (or warm) area and the right side simulates the outside (or cold) area.
According to the laws of physics, the warm air on the left of the image goes up by natural convection and escapes to the cooler side while the heavier cold air penetrates from the outside flowing through the floor. As the air tends to equalize temperatures and pressures and the warm inside is not thermally protected from the outside, the air mixes and we can’t see two separate thermal areas. In this situation we waste lots of energy and the heating is not able to keep the building comfortable.
The air jet of the air curtain placed on top clearly divides the warm and the cold area in two thermal zones. The air curtain keeps the internal environment on the left side of the image at a comfortable warm temperature and avoids cold air penetration from the outside. In this second situation, the air curtain saves up to 80% of the energy given by the heating.
Poorly designed air curtains, wrongly selected units (less powerful) or an inadequate installation will make us lose part of or even all the advantages. Therefore installing an air curtain will be the worst option.
EC and AC technology in comparison
The EC technology (EC = Electronically Commutated) combines the AC with the DC voltage, providing the best of both technologies: the motor runs on a DC voltage, but on a normal AC supply. The EC motor transforms the voltage within the motor. The nonrotating part of the motor (stator) includes an electronic PCB board which incorporates the power transformation of AC into DC, as well as the controls. EC motors have no slippage losses, thus increasing efficiency compared to AC motors.
EC Motor Principle
By a rectifier the mains voltage in the commutation electronic is converted in d.c. voltage. The motor voltage is made available for the motor (dependent of position) by an inverter (similar to the principle of the frequency converter). In deviation from the frequency converter the EC-commutation electronic decides depending on the position, the direction of rotation and speed specification how the motor phases are energized in the stator (commutation). Permanent magnet generates in the rotor a magnetic field, which is needed for the torque application. Hereby, a high efficient, low-noise and variable speed control is possible.
Advantages and Benefits
The Rosenberg EC Air curtains are fascinatingly efficient, reducing the running cost of the ventilation up to 65%.
• Energy savings: minimum power consumption and greater efficiency than an AC equivalent.
• Low motor temperature: Provides a longer lifespan than an AC equivalent.
• Compact: the electronic components and the power trans-formation are completely integrated within the motor.
• High performance: fan speed can exceed 3.600 rpm.