Buildings.Obsolete.Examples.VAVReheat.BaseClasses

Package with base classes

Information

This package contains base classes.

Extends from Modelica.Icons.BasesPackage (Icon for packages containing base classes).

Package Content

Name Description
Buildings.Obsolete.Examples.VAVReheat.BaseClasses.VAVBranch VAVBranch Supply branch of a VAV system

Buildings.Obsolete.Examples.VAVReheat.BaseClasses.VAVBranch Buildings.Obsolete.Examples.VAVReheat.BaseClasses.VAVBranch

Supply branch of a VAV system

Buildings.Obsolete.Examples.VAVReheat.BaseClasses.VAVBranch

Information

Model for a VAV supply branch. The terminal VAV box has a pressure independent damper and a water reheat coil. The pressure independent damper model includes an idealized flow rate controller and requires a discharge air flow rate set-point (normalized to the nominal value) as a control signal.

Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).

Parameters

TypeNameDefaultDescription
replaceable package MediumAModelica.Media.Interfaces.Pa...Medium model for air
replaceable package MediumWModelica.Media.Interfaces.Pa...Medium model for water
BooleanallowFlowReversaltrue= false to simplify equations, assuming, but not enforcing, no flow reversal
MassFlowRatem_flow_nominal Mass flow rate of this thermal zone [kg/s]
VolumeVRoo Room volume [m3]

Connectors

TypeNameDescription
replaceable package MediumAMedium model for air
replaceable package MediumWMedium model for water
FluidPort_aport_aFluid connector a1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_aport_bFluid connector b (positive design flow direction is from port_a1 to port_b1)
input RealInputyVAVSignal for VAV damper
input RealInputyValActuator position for reheat valve (0: closed, 1: open)
output RealOutputy_actualActual VAV damper position

Modelica definition

model VAVBranch "Supply branch of a VAV system" extends Modelica.Blocks.Icons.Block; replaceable package MediumA = Modelica.Media.Interfaces.PartialMedium "Medium model for air"; replaceable package MediumW = Modelica.Media.Interfaces.PartialMedium "Medium model for water"; parameter Boolean allowFlowReversal=true "= false to simplify equations, assuming, but not enforcing, no flow reversal"; parameter Modelica.Units.SI.MassFlowRate m_flow_nominal "Mass flow rate of this thermal zone"; parameter Modelica.Units.SI.Volume VRoo "Room volume"; Buildings.Fluid.Actuators.Dampers.PressureIndependent vav( redeclare package Medium = MediumA, m_flow_nominal=m_flow_nominal, dpDamper_nominal=220 + 20, allowFlowReversal=allowFlowReversal) "VAV box for room"; Buildings.Fluid.HeatExchangers.DryCoilEffectivenessNTU terHea( redeclare package Medium1 = MediumA, redeclare package Medium2 = MediumW, m1_flow_nominal=m_flow_nominal, m2_flow_nominal=m_flow_nominal*1000*(50 - 17)/4200/10, Q_flow_nominal=m_flow_nominal*1006*(16.7 - 50), configuration=Buildings.Fluid.Types.HeatExchangerConfiguration.CounterFlow, dp1_nominal=0, from_dp2=true, dp2_nominal=0, allowFlowReversal1=allowFlowReversal, allowFlowReversal2=false, T_a1_nominal=289.85, T_a2_nominal=355.35) "Heat exchanger of terminal box"; Buildings.Fluid.Sources.Boundary_pT sinTer( redeclare package Medium = MediumW, p(displayUnit="Pa") = 3E5, nPorts=1) "Sink for terminal box "; Modelica.Fluid.Interfaces.FluidPort_a port_a( redeclare package Medium = MediumA) "Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)"; Modelica.Fluid.Interfaces.FluidPort_a port_b( redeclare package Medium = MediumA) "Fluid connector b (positive design flow direction is from port_a1 to port_b1)"; Buildings.Fluid.Sensors.MassFlowRate senMasFlo( redeclare package Medium = MediumA, allowFlowReversal=allowFlowReversal) "Sensor for mass flow rate"; Modelica.Blocks.Math.Gain fraMasFlo(k=1/m_flow_nominal) "Fraction of mass flow rate, relative to nominal flow"; Modelica.Blocks.Math.Gain ACH(k=1/VRoo/1.2*3600) "Air change per hour"; Buildings.Fluid.Sources.MassFlowSource_T souTer( redeclare package Medium = MediumW, nPorts=1, use_m_flow_in=true, T=323.15) "Source for terminal box "; Modelica.Blocks.Interfaces.RealInput yVAV "Signal for VAV damper"; Modelica.Blocks.Interfaces.RealInput yVal "Actuator position for reheat valve (0: closed, 1: open)"; Buildings.Controls.OBC.CDL.Continuous.MultiplyByParameter gaiM_flow(final k= m_flow_nominal*1000*15/4200/10) "Gain for mass flow rate"; Modelica.Blocks.Interfaces.RealOutput y_actual "Actual VAV damper position"; equation connect(fraMasFlo.u, senMasFlo.m_flow); connect(vav.port_b, senMasFlo.port_a); connect(ACH.u, senMasFlo.m_flow); connect(souTer.ports[1], terHea.port_a2); connect(port_a, terHea.port_a1); connect(senMasFlo.port_b, port_b); connect(terHea.port_b1, vav.port_a); connect(vav.y, yVAV); connect(souTer.m_flow_in, gaiM_flow.y); connect(sinTer.ports[1], terHea.port_b2); connect(gaiM_flow.u, yVal); connect(vav.y_actual, y_actual); end VAVBranch;