modelSystem5

Open loop model with system on/off control

Extends from Buildings.Examples.Tutorial.CDL.BaseClasses.PartialOpenLoop.

Information

In this step, we added the controller for the system on/off control.

Implementation

This model was built as follows:

  1. First, we copied the controller Buildings.Examples.Tutorial.CDL.Controls.OpenLoopSystemOnOff to create the block Buildings.Examples.Tutorial.CDL.Controls.SystemOnOff.

  2. In this new block, we implemented the on/off control by using both Buildings.Controls.OBC.CDL.Reals.Subtract and Buildings.Controls.OBC.CDL.Reals.Hysteresis to determine whether the system should be on, which is the case if both, the outside air temperature and the room air temperature are below a limit. If either is above this limit, plus a deadband, the system is off.

  3. We also implemented the open loop validation Buildings.Examples.Tutorial.CDL.Controls.Validation.SystemOnOff to ensure that the controller is implemented correctly.

Exercise

Create a model, such as this model. To do so,

  1. Copy Buildings.Examples.Tutorial.CDL.System4.

  2. Implement the controller for the system on/off control.

    Make a small unit test to verify that the controller is implemented correctly.

  3. Use this new controller instead of the open loop controller conSysSta.

Simulate the system to verify that the system is switched off if the room temperature exceeeds its set point plus half the dead band. This should yield a plot similar to the one below.

Temperatures and control signals.

Components

TypeNameDefaultDescription
Controls.BoilerReturnconBoiRetController for boiler return water temperature
Controls.SystemOnOffconSysStaController that switches the system on and off
Controls.OpenLoopRadiatorSupplyconRadSupController for the mixing valve for the radiator supply water
Controls.EquipmentOnOffconEquStaController that switches the equipment on and off
Buildings.Controls.OBC.CDL.Conversions.BooleanToRealradPumConType conversion for radiator pump signal
Buildings.Controls.OBC.CDL.Conversions.BooleanToRealboiPumConType conversion for boiler pump signal
Buildings.Controls.OBC.CDL.Conversions.BooleanToRealboiSigConType conversion for boiler signal

Revisions

  • February 18, 2020, by Michael Wetter:
    First implementation.