blockSystemOnOff

Controller for system on/off
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Information

Controller that takes as an input the outside air temperature TOut and the room air temperature TRoo, and outputs the system on command onSys.

The system on command is true if both conditions are satisfied: The outside air temperature is below a limit of TOutLow(=16°C, adjustable) and the room air temperature is below TRooSet-dTRoo/2, where TRooSet is the room air temperature setpoint (=20.5°C, adjustable) and dTRoo is the deadband (=1 Kelvin, adjustable). Otherwise, the system on command is false.

Parameters

TypeNameDefaultDescription
RealTRooSet293.65Room air temperature set point
RealdTRoo1Room air temperature dead band
RealTOutLow289.15Outdoor temperature below which system is allowed to switch on

Connectors

TypeNameDefaultDescription
Buildings.Controls.OBC.CDL.Interfaces.RealInputTOutOutdoor air temperature
Buildings.Controls.OBC.CDL.Interfaces.RealInputTRooRoom air temperature
Buildings.Controls.OBC.CDL.Interfaces.BooleanOutputonSysSystem on command

Components

TypeNameDefaultDescription
Buildings.Controls.OBC.CDL.Reals.Sources.ConstantTSetOutSet point for outdoor air temperature plus half the dead band
Buildings.Controls.OBC.CDL.Reals.Sources.ConstantTSetRooSet point for room air temperature
Buildings.Controls.OBC.CDL.Logical.Andand1And operator to switch boiler on based on temperature and system on command
Buildings.Controls.OBC.CDL.Reals.SubtractsubInputs different
Buildings.Controls.OBC.CDL.Reals.HysteresisonTOutOn/off control based on outside air temperature
Buildings.Controls.OBC.CDL.Reals.Subtractsub1Inputs different
Buildings.Controls.OBC.CDL.Reals.HysteresisonTRooOn/off control based on room air temperature

Revisions

  • December 11, 2023, by Jianjun Hu:
    Reimplemented on-off control to avoid using the obsolete OnOffController. This is for #3595.
  • February 18, 2020, by Michael Wetter:
    First implementation.