Buildings.HeatTransfer

Package with heat transfer models

Information

This package contains models for heat transfer elements.

Package Content

Name Description

ConductorSingleLayer Model for single layer heat conductance

Data Data for heat transfer models

Examples Collection of models that illustrate model use and test models

Name	Description
ConductorSingleLayer	Model for single layer heat conductance
Data	Data for heat transfer models
Examples	Collection of models that illustrate model use and test models

Buildings.HeatTransfer.ConductorSingleLayer

Model for single layer heat conductance

Buildings.HeatTransfer.ConductorSingleLayer

Information

This is a model of a heat conductor with energy storage. The construction has n>1 state variables, of which one is located at each of the surfaces. The thickness of the construction is divided into n-1 layers that conduct heat between the states. To build multi-layer constructions, one instance of this model can be made for each layer, and the layers can be connected with each other. A Modelica translator should then collapse the state variables at the surfaces of two adjacent layers into one state variable.

Extends from Buildings.BaseClasses.BaseIcon (Base icon).

Parameters

Type Name Default Description

Length x Construction thickness [m]

Area A Heat transfer area [m2]

Integer n 2 Number of states

Solids mat Construction material

Type	Name	Default	Description
Length	x		Construction thickness [m]
Area	A		Heat transfer area [m2]
Integer	n	2	Number of states
Solids	mat		Construction material

Connectors

Type Name Description

HeatPort_a port_a

HeatPort_b port_b

Type	Name	Description
HeatPort_a	port_a
HeatPort_b	port_b

Modelica definition

model ConductorSingleLayer "Model for single layer heat conductance"
  extends Buildings.BaseClasses.BaseIcon;

  parameter Modelica.SIunits.Length x "Construction thickness";
  parameter Modelica.SIunits.Area A "Heat transfer area";
  parameter Integer n = 2 "Number of states";
  parameter Buildings.HeatTransfer.Data.Solids mat "Construction material";
  Modelica.SIunits.TemperatureDifference dT "port_a.T - port_b.T";
  Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a port_a;
  Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_b port_b;
  Modelica.Thermal.HeatTransfer.Components.HeatCapacitor cap[n](
      each C(fixed=false)) "Model for heat capacity";
  Modelica.Thermal.HeatTransfer.Components.ThermalConductor con[n-1](
     each G = A*mat.k/(x/(n-1))) "Model for heat conductance";
  final parameter Modelica.SIunits.CoefficientOfHeatTransfer U = mat.k/x 
    "U-value (without surface heat transfer coefficients)";
  final parameter Modelica.SIunits.ThermalConductance G = U*A 
    "Thermal conductance of construction";
  final parameter Modelica.SIunits.ThermalResistance R = 1/G 
    "Thermal conductance of construction";
initial equation 
  // nodes at surface have only 1/2 the layer thickness
  cap[1].C = A * x/(n-1) * mat.d * mat.c / 2;
  cap[n].C = cap[1].C;
  for i in 2:n-1 loop
    cap[i].C = A * x/(n-1) * mat.d * mat.c;
  end for;
equation 
   dT = port_a.T - port_b.T;
  connect(port_a, cap[1].port);
  for i in 1:n-1 loop
    connect(cap[i].port, con[i].port_a);
    connect(con[i].port_b, cap[i+1].port);
  end for;
  connect(cap[n].port, port_b);
end ConductorSingleLayer;

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