modelGuideline36Winter

Variable air volume flow system with terminal reheat and five thermal zones controlled using an ASHRAE G36 controller

Extends from Modelica.Icons.Example (Icon for runnable examples), Buildings.Examples.VAVReheat.BaseClasses.HVACBuilding (Partial model that contains the HVAC and building model).

Information

This model consist of an HVAC system, a building envelope model and a model for air flow through building leakage and through open doors.

The HVAC system is a variable air volume (VAV) flow system with economizer and a heating and cooling coil in the air handler unit. There is also a reheat coil and an air damper in each of the five zone inlet branches.

See the model Buildings.Examples.VAVReheat.BaseClasses.PartialHVAC for a description of the HVAC system, and see the model Buildings.ThermalZones.EnergyPlus_24_2_0.Examples.SmallOffice.BaseClasses.Floor for a description of the building envelope.

The control is based on ASHRAE Guideline 36, and implemented using the sequences from the library Buildings.Controls.OBC.ASHRAE.G36 for multi-zone VAV systems with economizer. The schematic diagram of the HVAC and control sequence is shown in the figure below.

image

A similar model but with a different control sequence can be found in Buildings.ThermalZones.EnergyPlus_24_2_0.Examples.SmallOffice.ASHRAE2006Winter.. Note that this model, because of the frequent time sampling, has longer computing time than Buildings.Examples.VAVReheat.ASHRAE2006. The reason is that the time integrator cannot make large steps because it needs to set a time step each time the control samples its input.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.VolumeVRooCor (from HVACBuilding)flo.VRooCorRoom volume corridor
Modelica.Units.SI.VolumeVRooSou (from HVACBuilding)flo.VRooSouRoom volume south
Modelica.Units.SI.VolumeVRooNor (from HVACBuilding)flo.VRooNorRoom volume north
Modelica.Units.SI.VolumeVRooEas (from HVACBuilding)flo.VRooEasRoom volume east
Modelica.Units.SI.VolumeVRooWes (from HVACBuilding)flo.VRooWesRoom volume west
Modelica.Units.SI.AreaAFloCor (from HVACBuilding)flo.AFloCorFloor area corridor
Modelica.Units.SI.AreaAFloSou (from HVACBuilding)flo.AFloSouFloor area south
Modelica.Units.SI.AreaAFloNor (from HVACBuilding)flo.AFloNorFloor area north
Modelica.Units.SI.AreaAFloEas (from HVACBuilding)flo.AFloEasFloor area east
Modelica.Units.SI.AreaAFloWes (from HVACBuilding)flo.AFloWesFloor area west
Realconv (from HVACBuilding)1.2/3600Conversion factor for nominal mass flow rate
Modelica.Units.SI.MassFlowRatemCor_flow_nominal (from HVACBuilding)Design mass flow rate core
Modelica.Units.SI.MassFlowRatemSou_flow_nominal (from HVACBuilding)Design mass flow rate south
Modelica.Units.SI.MassFlowRatemEas_flow_nominal (from HVACBuilding)Design mass flow rate east
Modelica.Units.SI.MassFlowRatemNor_flow_nominal (from HVACBuilding)Design mass flow rate north
Modelica.Units.SI.MassFlowRatemWes_flow_nominal (from HVACBuilding)Design mass flow rate west
Modelica.Units.SI.MassFlowRate[5]mCooVAV_flow_nominal (from HVACBuilding){mSou_flow_nominal, mEas_flow_nominal, mNor_flow_nominal, mWes_flow_nominal, mCor_flow_nominal}Design mass flow rate of each zone
Modelica.Units.SI.TemperatureTHeaWatInl_nominal (from HVACBuilding)45 + 273.15Reheat coil nominal inlet water temperature
RealACHCor4Design air change per hour core
RealACHSou4Design air change per hour south
RealACHEas6Design air change per hour east
RealACHNor4Design air change per hour north
RealACHWes6Design air change per hour west

Components

TypeNameDefaultDescription
Buildings.Examples.VAVReheat.BaseClasses.PartialHVAChvac (from HVACBuilding)
Buildings.Examples.VAVReheat.BaseClasses.PartialFloorflo (from HVACBuilding)
Buildings.BoundaryConditions.WeatherData.ReaderTMY3weaDat (from HVACBuilding)Weather data reader
Fluid.Sources.Boundary_pTsinHea (from HVACBuilding)Sink for heating coil
Fluid.Sources.Boundary_pTsouHea (from HVACBuilding)Source for heating coil
Fluid.Sources.Boundary_pTsinCoo (from HVACBuilding)Sink for cooling coil
Fluid.Sources.Boundary_pTsouCoo (from HVACBuilding)Source for cooling coil loop
Fluid.Sources.Boundary_pTsouHeaTer (from HVACBuilding)Source for heating of terminal boxes
Fluid.Sources.Boundary_pTsinHeaTer (from HVACBuilding)Source for heating of terminal boxes

Revisions

  • December 20, 2021, by Michael Wetter:
    Changed parameter declarations and added optimal start up. This is for issue #2829.
  • October 4, 2021, by Michael Wetter:
    Refactored Buildings.Examples.VAVReheat and its base classes to separate building from HVAC model.
    This is for issue #2652.
  • September 3, 2021, by Michael Wetter:
    Updated documentation.
    This is for issue #2600.
  • November 25, 2019, by Milica Grahovac:
    Impementation of Buildings.Examples.VAVReheat.Guideline36 model with an EnergyPlus thermal zone instance.