modelExample1v2

Example 1 model with mixing volume
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Extends from BuildingSystems.Fluid.Examples.Performance.BaseClasses.Example1 (Example 1 partial model).

Information

This example is an extension of BuildingSystems.Fluid.Examples.Performance.Example1v1 and demonstrates the use of mixing volumes for decoupling the algebraic loop that solves for the enthalpy of the system.

Example1v1:

Sizes of nonlinear systems of equations: {6, 21, 46}

Sizes after manipulation of the nonlinear systems: {1, 19, 22}

Example1v2 using mixing volumes:

Sizes of nonlinear systems of equations: {6, 21, 4}

Sizes after manipulation of the nonlinear systems: {1, 19, 1}

See Jorissen et al. (2015) for a discussion.

References

  • Filip Jorissen, Michael Wetter and Lieve Helsen.
    Simulation speed analysis and improvements of Modelica models for building energy simulation.
    Submitted: 11th Modelica Conference. Paris, France. Sep. 2015.

Parameters

TypeNameDefaultDescription
Realm_flow_nominal (from Example1)0.1Gain value multiplied with input signal
Modelica.Units.SI.Timetau10Time constant at nominal flow

Components

TypeNameDefaultDescription
BuildingSystems.Fluid.Sources.Boundary_pTbou (from Example1)Boundary for pressure boundary condition
Fluid.Movers.FlowControlled_m_flowpump (from Example1)Pump model with unidirectional flow
BuildingSystems.Fluid.HeatExchangers.Heater_Thea (from Example1)Heater
Modelica.Blocks.Sources.Pulsepulse (from Example1)Pulse input
Modelica.Blocks.Math.Gaingain (from Example1)Gain for m_flow_nominal
BuildingSystems.Fluid.Actuators.Valves.ThreeWayLinearval (from Example1)Three way valve with constant input
Modelica.Blocks.Sources.Constantconst (from Example1)Constant valve set point
Modelica.Blocks.Sources.BooleanConstantallowFlowReversal (from Example1)Block for setting allowFlowReversal in components
BuildingSystems.Fluid.FixedResistances.PressureDropres (from Example1)Fluid resistance for splitting flow
Modelica.Blocks.Sources.IntegerConstantnRes (from Example1)Number of parallel branches
Modelica.Blocks.Sources.BooleanConstantfrom_dp (from Example1)Block for setting from_dp in res
Fluid.Delays.DelayFirstOrdervolMixing volumes for adding states in enthalpy circuit

Revisions

  • August 31, 2015, by Michael Wetter:
    Added missing each in declaration of the energy balance for the volume.
  • July 14, 2015, by Michael Wetter:
    Revised documentation.
  • April 17, 2015, by Filip Jorissen:
    First implementation.