Ventilation inlet stream principles
Mechanical Ventilation with Heat Recovery (MVHR) – ventilation for work and living areas.
MVHR ventilation improves the thermal and atmospheric indoor climate with respect to air temperature, humidity and foreign/harmful substances and particles. The Airmaster ventilation is demand-controlled (DCV – Demand Controlled Ventilation), with ventilation units developed according to the two different supply principles in the comfort ventilation category: the mixing principle and the displacement principle.
The mixing principle
With the mixing principle, the density of indoor pollutants is controlled by mixing fresh air with the air in the room. This principle is also sometimes referred to as dilution ventilation, as it “dilutes” the air in the room with fresh outdoor air. The efficiency of the mixing principle is ensured by the Coanda effect.
The Coanda effect
The fresh air is blown in at a relatively high speed and “clings” to the ceiling before slowly descending, which is known as the Coanda effect.
The Coanda effect “entrains” the air in the room, ensuring that the fresh air and the room air are mixed efficiently. The entrainment of the air in the room ensures uniform air quality in the room, while reducing the air velocity of the supply jet. This way, draughts in the occupied area are avoided.
Proper installation and adjustment are, however, crucial to avoiding draughts.
Demo, the Coanda-effect
Inlet stream for wall-mounted units
Wall-mounted Airmaster ventilation - mixing ventilation principle
All wall-mounted models ventilate according to the mixing principle, in which fresh air is fed into the room at ceiling level, exploiting the Coanda effect.
The AM 1000 air handling unit is available with an adaptive inlet, which adjusts the throw in relation to the airflow relative to the length of the room.
Wall-mounted Airmaster ventilation with inlet stream seen from the side
Inlet stream for floor-standing units
The mixing principle is also used for Airmaster’s floor-standing models (AM 900, AM 1200), with fresh air fed upwards into the room to exploit the Coanda effect.
Adjustable inlet opening
Floor-standing models AM 900 and AM 1200 are fitted with adjustable inlet openings. The opening can be adjusted according to requirement, ensuring the right throw length according to the size of the room.
The throw length can be easily varied by changing the inlet opening/louvre angle.
The illustration shows two floor-standing AM 1200, one standing close to a wall and the other freestanding. Inlet viewed from the side.
Floor-standing AM 900 - mixed ventilation.
Floor-standing AM 1200 placed at right-angles to a wall as a room divider. Airflow and direction are adjusted using the louvred grille.
The displacement principle
Floor-standing AM 900 - displacement ventilation with inlet stream seen from the side.
Airmaster’s floor-standing model AM 900 is also available as a displacement model. The displacement ventilation principle feeds fresh air into the room at low velocity at floor level. The fresh air is blown in at a temperature a couple of degrees lower than the
room temperature.
The air is distributed over the entire floor due to the difference in density between cold and warm air. The low inlet velocity avoids draughts in the room.
Floor-standing AM 900 - displacement ventilation.
