5.8.3 Extract (room) temperature cascade control (TCasCtlH21y
and TCasCtlC21y)
Cascade control is useful for controlling the room temperature in situations with
strong heat fluctuations in the room, e.g. due to internal heat gains. The basic room
temperature level is controlled with a standard heating system (radiator, floor
heating, etc.) to its own, slightly lower setpoint value and at the same time the
ventilation temperature control aims to keep the room temperature at its setpoint
value by balancing the internal heat fluctuations.
In cascade control, the preset control variable is the extract temperature sensor
(TEx). If TEx is not connected or a room temperature control is preferred, the room
temperature TR can be selected.
Separate room/exhaust air temperature setpoints can be defined for the
UNOCCUPIED, ECONOMY and COMFORT operating modes. Individual
tolerances before using heating and cooling coils can be defined for
UNOCCUPIED, ECONOMY and COMFORT. Special operating modes use the
same setpoint as the normal operating mode shortly before activation
Depending on whether the current extract air (room) temperature TR is above or
below the extract air (room) setpoint, the supply air temperature setpoint is shifted
a few degrees up or down to compensate for heat gains or deficits in the rooms.
Adjustable limits for maximum and minimum supply air temperature setpoint
ensure that the user does not feel uncomfortable when the room is heated up or
cooling down.
Determination of the supply air setpoint
Setpoint calculation, weather compensation and actuator's output are the same
as described for the supply air temperature before
Application functionalities
Air temperature control
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