modelExample1v2

Example 1 model with mixing volume

Extends from Buildings.Fluid.Examples.Performance.BaseClasses.Example1 (Example 1 partial model).

Information

This example is an extension of Buildings.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
Buildings.Fluid.Sources.Boundary_pTbou (from Example1)Boundary for pressure boundary condition
Fluid.Movers.FlowControlled_m_flowpump (from Example1)Pump model with unidirectional flow
Buildings.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
Buildings.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
Buildings.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.