Buildings.Fluid.HeatExchangers.Examples.BaseClasses

Information

This package contains base classes that are used to construct the models in Buildings.Fluid.HeatExchangers.Examples.

Package Content

Buildings.Fluid.HeatExchangers.Examples.BaseClasses.EffectivenessNTUMassFlow

Parameters

Type	Name	Default	Description
Temperature	T_a1_nominal	5 + 273.15	[K]
Temperature	T_b1_nominal	10 + 273.15	[K]
Temperature	T_a2_nominal	30 + 273.15	[K]
Temperature	T_b2_nominal	15 + 273.15	[K]
HeatFlowRate	Q_flow_nominal	m1_flow_nominal*4200*(T_a1_n...	Nominal heat transfer [W]
MassFlowRate	m1_flow_nominal	0.1	Nominal mass flow rate medium 1 [kg/s]
MassFlowRate	m2_flow_nominal	m1_flow_nominal*4200/1000*(T...	Nominal mass flow rate medium 2 [kg/s]

Modelica definition

partial model EffectivenessNTUMassFlow 
  "Partial model of epsilon-NTU coil that tests variable mass flow rates"
  package Medium1 = Buildings.Media.ConstantPropertyLiquidWater;
  package Medium2 = Buildings.Media.PerfectGases.MoistAirUnsaturated;
  parameter Modelica.SIunits.Temperature T_a1_nominal=5 + 273.15;
  parameter Modelica.SIunits.Temperature T_b1_nominal=10 + 273.15;
  parameter Modelica.SIunits.Temperature T_a2_nominal=30 + 273.15;
  parameter Modelica.SIunits.Temperature T_b2_nominal=15 + 273.15;
  parameter Modelica.SIunits.HeatFlowRate Q_flow_nominal = m1_flow_nominal*4200*(T_a1_nominal-T_b1_nominal) 
    "Nominal heat transfer";
  parameter Modelica.SIunits.MassFlowRate m1_flow_nominal=0.1 
    "Nominal mass flow rate medium 1";
  parameter Modelica.SIunits.MassFlowRate m2_flow_nominal=m1_flow_nominal*4200/
      1000*(T_a1_nominal - T_b1_nominal)/(T_b2_nominal - T_a2_nominal) 
    "Nominal mass flow rate medium 2";
  Buildings.Fluid.Sources.Boundary_pT sin_2(
    redeclare package Medium = Medium2,
    use_p_in=false,
    p(displayUnit="Pa") = 101325,
    T=T_a2_nominal);
  Buildings.Fluid.Sources.MassFlowSource_T sou_2(
    redeclare package Medium = Medium2,
    T=T_a2_nominal,
    X={0.02,1 - 0.02},
    use_T_in=true,
    use_X_in=true,
    m_flow=m2_flow_nominal,
    use_m_flow_in=true);
  Buildings.Fluid.Sources.Boundary_pT sin_1(
    redeclare package Medium = Medium1,
    use_p_in=false,
    p=300000,
    T=T_a1_nominal);
  Buildings.Fluid.Sources.MassFlowSource_T sou_1(
    redeclare package Medium = Medium1,
    use_m_flow_in=true,
    use_T_in=false,
    T=T_a1_nominal);

  inner Modelica.Fluid.System system;
  Modelica.Blocks.Sources.Constant const(k=0.8);
  Buildings.Utilities.Psychrometrics.X_pTphi x_pTphi(use_p_in=false);
  Modelica.Blocks.Sources.Constant const1(k=T_a2_nominal);
  Modelica.Blocks.Math.Gain mWat_flow(k=m1_flow_nominal) "Water mass flow rate";
  Modelica.Blocks.Sources.TimeTable mWatGai(
    table=[0,1; 3600*0.1,1; 3600*0.2,0.01; 3600*0.3,0.01]) 
    "Gain for water mass flow rate";
  Modelica.Blocks.Sources.TimeTable mAirGai(
    table=[0,1; 3600*0.5,1; 3600*0.6,-1; 3600*0.7,0; 3600*1,0]) 
    "Gain for air mass flow rate";
  Modelica.Blocks.Math.Gain mAir_flow(k=m2_flow_nominal) "Air mass flow rate";
equation 
  connect(x_pTphi.X, sou_2.X_in);
  connect(const.y, x_pTphi.phi);
  connect(const1.y, x_pTphi.T);
  connect(const1.y, sou_2.T_in);
  connect(mWat_flow.y, sou_1.m_flow_in);
  connect(mAir_flow.y, sou_2.m_flow_in);
  connect(mAirGai.y, mAir_flow.u);
  connect(mWatGai.y, mWat_flow.u);
end EffectivenessNTUMassFlow;