modelSystem1

Open loop model

Extends from Buildings.Examples.Tutorial.CDL.BaseClasses.PartialOpenLoop (Partial model with open loop system).

Information

This model extends from the open loop partial model Buildings.Examples.Tutorial.CDL.BaseClasses.PartialOpenLoop, which implements the HVAC system model and a simple room. In this partial model, the room is modeled as a first order response.

Implementation

To set control inputs, we instantiated Buildings.Controls.OBC.CDL.Reals.Sources.Constant and connected them to the pumps, the boiler and the valves.

Exercise

Create a model, such as this model, that extends from Buildings.Examples.Tutorial.CDL.BaseClasses.PartialOpenLoop and adds constant input signals for the valves, pumps and the boiler. Valves should be fully open (y=1), the boiler should be operating (y=1) and the mass flow rates of the pumps should be set to the parameter value of mRad_flow_nominal and mBoi_flow_nominal.

Simulate the model for January 15 to 16 and plot the open loop temperatures as shown below, which corresponds to a start time of 15*24*3600=1296000 seconds and a stop time of 1382400 seconds.

Open loop temperatures.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.HeatFlowRateQ_flow_nominal (from PartialOpenLoop)20000Nominal heat flow rate of radiator
Modelica.Units.SI.TemperatureTRadSup_nominal (from PartialOpenLoop)273.15 + 50Radiator nominal supply water temperature
Modelica.Units.SI.TemperatureTRadRet_nominal (from PartialOpenLoop)273.15 + 40Radiator nominal return water temperature
Modelica.Units.SI.MassFlowRatemRad_flow_nominal (from PartialOpenLoop)Q_flow_nominal/4200/(TRadSup_nominal - TRadRet_nominal)Radiator nominal mass flow rate
Modelica.Units.SI.TemperatureTBoiSup_nominal (from PartialOpenLoop)273.15 + 70Boiler nominal supply water temperature
Modelica.Units.SI.TemperatureTBoiRet_min (from PartialOpenLoop)273.15 + 60Boiler minimum return water temperature
Modelica.Units.SI.MassFlowRatemBoi_flow_nominal (from PartialOpenLoop)Q_flow_nominal/4200/(TBoiSup_nominal - TBoiRet_min)Boiler nominal mass flow rate
Modelica.Units.SI.MassFlowRatemRadVal_flow_nominal (from PartialOpenLoop)Q_flow_nominal/4200/(TBoiSup_nominal - TRadRet_nominal)Radiator nominal mass flow rate
Modelica.Units.SI.VolumeV (from PartialOpenLoop)6*10*3Room volume
Modelica.Units.SI.MassFlowRatemA_flow_nominal (from PartialOpenLoop)V*1.2*6/3600Nominal mass flow rate
Modelica.Units.SI.HeatFlowRateQRooInt_flow (from PartialOpenLoop)4000Internal heat gains of the room

Connectors

TypeNameDefaultDescription
BoundaryConditions.WeatherData.BusweaBus (from PartialOpenLoop)Weather data bus

Components

TypeNameDefaultDescription
Buildings.Fluid.MixingVolumes.MixingVolumevol (from PartialOpenLoop)Room air volume
Modelica.Thermal.HeatTransfer.Components.ThermalConductortheCon (from PartialOpenLoop)Thermal conductance with the ambient
Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlowpreHea (from PartialOpenLoop)Prescribed heat flow
Modelica.Thermal.HeatTransfer.Components.HeatCapacitorheaCap (from PartialOpenLoop)Heat capacity for furniture and walls
Buildings.Controls.OBC.CDL.Reals.Sources.TimeTabletimTab (from PartialOpenLoop)Time table for internal heat gain
Buildings.Fluid.HeatExchangers.Radiators.RadiatorEN442_2rad (from PartialOpenLoop)Radiator
Buildings.Fluid.Sensors.TemperatureTwoPorttemSup (from PartialOpenLoop)Supply water temperature
Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensortemRoo (from PartialOpenLoop)Room temperature
Buildings.Fluid.Movers.FlowControlled_m_flowpumRad (from PartialOpenLoop)Pump for radiator
Buildings.Fluid.FixedResistances.Junctionmix (from PartialOpenLoop)Mixer between valve and radiators
Buildings.Fluid.FixedResistances.Junctionspl (from PartialOpenLoop)Splitter of boiler loop bypass
Buildings.Fluid.FixedResistances.Junctionspl2 (from PartialOpenLoop)Flow splitter in return from radiator
Buildings.Fluid.FixedResistances.Junctionmix2 (from PartialOpenLoop)Mixer
Buildings.Fluid.FixedResistances.Junctionspl4 (from PartialOpenLoop)Splitter for radiator loop valve bypass
Buildings.Fluid.Movers.FlowControlled_m_flowpumBoi (from PartialOpenLoop)Pump for boiler
Buildings.Fluid.Boilers.BoilerPolynomialboi (from PartialOpenLoop)Boiler
Buildings.Fluid.Actuators.Valves.ThreeWayEqualPercentageLinearvalRad (from PartialOpenLoop)Three-way valve for radiator loop
Buildings.Fluid.Sources.Boundary_pTpreSou (from PartialOpenLoop)Source for pressure and to account for thermal expansion of water
Buildings.Fluid.Actuators.Valves.ThreeWayEqualPercentageLinearvalBoi (from PartialOpenLoop)Three-way valve for boiler
Buildings.Fluid.Sensors.TemperatureTwoPorttemRet (from PartialOpenLoop)Return water temperature
Buildings.Fluid.FixedResistances.Junctionspl1 (from PartialOpenLoop)Splitter
Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensorsenTOut (from PartialOpenLoop)Outdoor temperature sensor
BoundaryConditions.WeatherData.ReaderTMY3weaDat (from PartialOpenLoop)Weather data reader
Modelica.Thermal.HeatTransfer.Sources.PrescribedTemperatureTOut (from PartialOpenLoop)Outside temperature
Buildings.Controls.OBC.CDL.Reals.Sources.Constanty1Control signal of 1
Buildings.Controls.OBC.CDL.Reals.Sources.Constanty2Control signal of 1
Buildings.Controls.OBC.CDL.Reals.Sources.Constanty3Constant control signal of 1
Buildings.Controls.OBC.CDL.Reals.Sources.Constanty4Control signal of 1
Buildings.Controls.OBC.CDL.Reals.Sources.Constanty5Control signal of 1

Revisions

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