modelMixedAirCO2

Mixed air room model with CO2 concentration simulated

Extends from Buildings.ThermalZones.Detailed.Examples.ElectroChromicWindow.

Information

Example that demonstrates how to add CO2 emission that scales with the number of person, and then add a feedback control that increases the outside air mass flow rate.

The gain gaiCO2 adds a CO2 mass flow rate of 8.18E-6 kg/s per person to the room. It is scaled with the number of person, as obtained from the block nPer. In this example, the number of person are zero except for 2 hours, starting at 11 AM. During this time, 5 people are in the room.

The sensor senCO2 measures the CO2 PPM in the room. This is used by the controller conPI to adjust the outside air flow rate. Two gains are used to normalize the control input. This is simply done to make it easier to configure the gains of the controller. The block addFlo increases the outdoor air flow rate above the base flow rate, which is set to mOut_flow. Plotting the control error shows that the set point is being tracked after a brief overshoot during the initial transient.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.MassFlowRatemOut_flow47*2/3600*1.2Typical outside air mass flow rate, unless increased by controller

Components

TypeNameDefaultDescription
Modelica.Blocks.Math.GaingaiCO2CO2 emission per person
Buildings.Fluid.Sensors.PPMsenCO2CO2 sensor that measures concentration in the room
Modelica.Blocks.Sources.ConstantCO2SetCO2 set point in PPM above the initial value
Modelica.Blocks.Math.GainnorCO2SetNormalization for CO2 set point
Modelica.Blocks.Math.GainnorCO2MeaNormalization for CO2 measurement
Buildings.Controls.Continuous.LimPIDconPIPI controller for fresh air supply, with negative minimum because of reverse action
Buildings.Controls.OBC.CDL.Reals.AddParameteraddFloGain that increases the mass flow rate above its typical value
Buildings.Controls.OBC.CDL.Reals.MultiplyByParametergaiFacGain that increases the mass flow rate above its typical value

Revisions

  • March 26, 2024, by Michael Wetter:
    Configured the sensor parameter to suppress the warning about being a one-port connection.
    This is for #3731
  • September 8, 2017, by Michael Wetter:
    First implementation.