Abstract: Disclosed is an air terminal device for a ventilation system for a building. The air terminal device includes a pressure box, with an inlet admitting supply air into the pressure box and outlet openings for admitting supply air out. The device further includes first and second cover plates, each arranged to control and change the open area of a plurality of the outlet openings. The outlet openings are arranged in a wall of the pressure box forming an outlet surface of the pressure box. The cover plate or cover plates are arranged to be in contact with and slide relative the outlet surface while changing the open area of the outlet openings. The first cover plate and the second cover plate are arranged to slide relative each other and to be in contact with and slide relative the outlet surface while changing the open area of the outlet openings.

Abstract: An Air Handling Unit for a ventilation system in a building has supply and extract air channels, each with an inlet and an outlet for guiding air to and from a building. Each air channel includes a damper controlling air flow. The air channels are in a heat exchanging relation to each other. The AHU also includes a fan and an Electronic Control Unit. The ECU outputs a defrost cycle initiation signal to defrost the heat recovery arrangement. The ECU outputs a defrost cycle termination signal to end the defrost cycle upon indication of the defrosting being completed. To optimize the defrost cycle time the ECU changes the first or second criterion for defrost cycle termination signal depending on the time for performing the defrost cycle such that the time period of the defrost cycle is prolonged/shortened when the defrost cycle time period is shorter/longer than preferred.

Abstract: An air terminal device for a ventilation system includes a pressure box, with an inlet admitting supply air into the pressure box and outlet openings for admitting supply air out. The air terminal device further includes a cover plate to control and change the open area of the outlet openings. The outlet openings are in a wall of the pressure box forming an outlet surface of the pressure box. The cover plates are arranged to make contact with and slide relative the outlet surface while changing the open area of the outlet openings. The cover plate is located on the high pressure side of the outlet surface. The cover plate cooperates with the outlet surface such that there is at least one outlet opening or suction opening being partly or fully covered by the cover plate also when the air terminal device is set to maximum flow.