Buildings.ThermalZones.ReducedOrder.RC.BaseClasses

Package with base classes for ROM

Information

This packages contains base clases for ROM models.

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

Package Content

Name	Description
ExteriorWall	Exterior wall consisting of variable number of RC elements
InteriorWall	Interior wall consisting of variable number of RC elements
ThermSplitter	A simple model which weights a given set of thermal inputs to calculate an average temperature and aggregated heat flow per output
splitFacVal	Share of vector entries at sum of vector for multiple vectors

Buildings.ThermalZones.ReducedOrder.RC.BaseClasses.ExteriorWall

Exterior wall consisting of variable number of RC elements

Buildings.ThermalZones.ReducedOrder.RC.BaseClasses.ExteriorWall

Information

ExteriorWall represents heat conduction and heat storage within walls. It links a variable number n of thermal resistances and capacities to a series connection. n thus defines the spatial discretization of thermal effects within the wall. All effects are considered as one-dimensional normal to the wall's surface. This model is thought for exterior wall elements that contribute to heat transfer to the outdoor. The RC-chain is defined via a vector of capacities CExt[n] and a vector of resistances RExt[n]. Resistances and capacities are connected alternately, starting with the first resistance RExt[1], from heat port_a to heat port_b. RExtRem is the resistance between the last capacity CExt[end] and the heat port_b.

Parameters

Type	Name	Description
Integer	n	Number of RC-elements
Thermal mass
ThermalResistance	RExt[n]	Vector of resistors, from port_a to port_b [K/W]
ThermalResistance	RExtRem	Resistance of remaining resistor RExtRem between capacitor n and port_b [K/W]
HeatCapacity	CExt[n]	Vector of heat capacities, from port_a to port_b [J/K]
Temperature	T_start	Initial temperature of capacities [K]

Connectors

Type	Name	Description
HeatPort_a	port_a	interior port
HeatPort_b	port_b	exterior port

Modelica definition

model ExteriorWall "Exterior wall consisting of variable number of RC elements" parameter Integer n(min = 1) "Number of RC-elements"; parameter Modelica.Units.SI.ThermalResistance RExt[n](each min=Modelica.Constants.small) "Vector of resistors, from port_a to port_b"; parameter Modelica.Units.SI.ThermalResistance RExtRem(min=Modelica.Constants.small) "Resistance of remaining resistor RExtRem between capacitor n and port_b"; parameter Modelica.Units.SI.HeatCapacity CExt[n](each min=Modelica.Constants.small) "Vector of heat capacities, from port_a to port_b"; parameter Modelica.Units.SI.Temperature T_start "Initial temperature of capacities"; Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a port_a "interior port"; Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_b port_b "exterior port"; Modelica.Thermal.HeatTransfer.Components.HeatCapacitor thermCapExt[n]( final C=CExt, each T(start=T_start)) "vector of thermal capacitors"; protected Modelica.Thermal.HeatTransfer.Components.ThermalResistor thermResExt[n]( final R=RExt) "vector of thermal resistors connecting port_a and capacitors"; Modelica.Thermal.HeatTransfer.Components.ThermalResistor thermResExtRem( final R=RExtRem) "single thermal resistor connecting least capacitor to port_b"; equation // Connecting inner elements thermResExt[i]--thermCapExt[i] to n groups for i in 1:n loop connect(thermResExt[i].port_b,thermCapExt[i].port); end for; // Connecting groups between each other thermCapExt[i] -- thermResExt[i+1] for i in 1:n-1 loop connect(thermCapExt[i].port,thermResExt[i+1].port_a); end for; // Connecting first RC element to port_a , // last RC-element to RExtRem and RExtRem to port_b connect(port_a,thermResExt[1].port_a); connect(thermCapExt[n].port,thermResExtRem.port_a); connect(thermResExtRem.port_b, port_b); end ExteriorWall;

Buildings.ThermalZones.ReducedOrder.RC.BaseClasses.InteriorWall

Interior wall consisting of variable number of RC elements

Buildings.ThermalZones.ReducedOrder.RC.BaseClasses.InteriorWall

Information

InteriorWall represents heat storage within walls. It links a variable number n of thermal resistances and capacities to a series connection. n thus defines the spatial discretization of thermal effects within the wall. All effects are considered as one-dimensional normal to the wall's surface. This model is thought for interior wall elements that only serve as heat storage elements. The RC-chain is defined via a vector of capacities CInt[n] and a vector of resistances RInt[n]. Resistances and capacities are connected alternately, starting with the first resistance RInt[1], from heat port_a into the wall.

Parameters

Type	Name	Description
Integer	n	Number of RC-elements
Thermal mass
ThermalResistance	RInt[n]	Vector of resistors, from port to capacitor [K/W]
HeatCapacity	CInt[n]	Vector of heat capacitors, from port to center [J/K]
Temperature	T_start	Initial temperature of capacities [K]

Connectors

Type	Name	Description
HeatPort_a	port_a	interior port

Modelica definition

model InteriorWall "Interior wall consisting of variable number of RC elements" parameter Integer n(min = 1) "Number of RC-elements"; parameter Modelica.Units.SI.ThermalResistance RInt[n](each min=Modelica.Constants.small) "Vector of resistors, from port to capacitor"; parameter Modelica.Units.SI.HeatCapacity CInt[n](each min=Modelica.Constants.small) "Vector of heat capacitors, from port to center"; parameter Modelica.Units.SI.Temperature T_start "Initial temperature of capacities"; Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a port_a "interior port"; Modelica.Thermal.HeatTransfer.Components.HeatCapacitor thermCapInt[n]( final C=CInt, each T(start=T_start)) "vector of capacitors"; protected Modelica.Thermal.HeatTransfer.Components.ThermalResistor thermResInt[n]( final R=RInt) "vector of resistors connecting port and capacitors"; equation // Connecting inner elements thermResInt[i]--thermCapInt[i] to n groups for i in 1:n loop connect(thermResInt[i].port_b,thermCapInt[i].port); end for; // Connecting groups between each other thermCapInt[i] -- thermResInt[i+1] for i in 1:n-1 loop connect(thermCapInt[i].port,thermResInt[i+1].port_a); end for; // Connecting first RC element to port_a port_a--thermResInt[1] connect(port_a,thermResInt[1].port_a); end InteriorWall;

Buildings.ThermalZones.ReducedOrder.RC.BaseClasses.ThermSplitter

A simple model which weights a given set of thermal inputs to calculate an average temperature and aggregated heat flow per output

Buildings.ThermalZones.ReducedOrder.RC.BaseClasses.ThermSplitter

Information

This model is used to weight thermal ports (inputs) according to given split factors per output port.

The model needs the dimensions of the splitted therm ports (for input and output ports resp.) and the split factors, which are between 0 and 1. Each row of the split factor matrix gives the split factors for one output port. The number of columns need to align with the number of input ports.

Parameters

Type	Name	Default	Description
Integer	nOut		Number of splitter outputs
Integer	nIn		Number of splitter inputs
Real	splitFactor[nOut, nIn]	fill(1/nOut, nOut, nIn)	Matrix of split factor for outputs (between 0 and 1 for each row)

Connectors

Type	Name	Description
HeatPort_a	portIn[nIn]	Single thermal input
HeatPort_a	portOut[nOut]	Set of thermal outputs

Modelica definition

model ThermSplitter "A simple model which weights a given set of thermal inputs to calculate an average temperature and aggregated heat flow per output" parameter Integer nOut "Number of splitter outputs"; parameter Integer nIn "Number of splitter inputs"; parameter Real splitFactor[nOut, nIn]= fill(1/nOut, nOut, nIn) "Matrix of split factor for outputs (between 0 and 1 for each row)"; Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a portIn[nIn] "Single thermal input"; Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a portOut[nOut] "Set of thermal outputs"; equation portOut.Q_flow = - portIn.Q_flow * transpose(splitFactor) "Connecting the output vector according to desired dimension"; portIn.T = portOut.T * splitFactor "Equivalent building temperature rerouted to SignalInput"; end ThermSplitter;

Buildings.ThermalZones.ReducedOrder.RC.BaseClasses.splitFacVal

Share of vector entries at sum of vector for multiple vectors

Information

Calculates the ratio of the surface areas of a wall to the total wall area, unless the area is zero. It subtracts the wall area AExt for first entry in AArray and AWin for second entry in AArray unless AArray[1] and/or AArray[2] are not zero. This is done separately for each orientation. Consequently, the function gives an nRow x nCol array back as output. Each row stands for one area in AArray and each column for one orientation in AExt and AWin. The function is used to calculate the split factors for Buildings.ThermalZones.ReducedOrder.RC.BaseClasses.ThermSplitter.

For internal gains, the calculation is:

SplitFac_i = AArray[i] /ATot

whereby ATot is the sum of AArray. To perform this, AExt and AWin can just be set to vectors of zeros with length 1. For solar radiation through windows, the window and wall area with the same orientation as the incoming radiation should be subtracted as these areas cannot be hit by the radiation. This needs to be done separately for each orientation and for exterior walls and windows only, according to:

SplitFac_i,k = (AArray[i] - AExt[k]) /(ATot - AExt[k] -AWin[k])

and

SplitFac_i,k = (AArray[i] - AWin[k]) /(ATot - AExt[k] - AWin[k])

respectively. For all other walls, the equation is:

SplitFac_i,k = AArray[i] /(ATot - AExt[k] - AWin[k])

Extends from Modelica.Icons.Function (Icon for functions).

Inputs

Type	Name	Description
Integer	nRow	Number of rows
Integer	nCol	Number of columns
Area	AArray[:]	Vector of areas [m2]
Area	AExt[nCol]	Vector of exterior wall areas [m2]
Area	AWin[nCol]	Vector of window areas [m2]

Outputs

Type	Name	Description
Real	splitFacValues[nRow, nCol]	Split factor values for ThermSplitter

Modelica definition

function splitFacVal "Share of vector entries at sum of vector for multiple vectors" extends Modelica.Icons.Function; input Integer nRow "Number of rows"; input Integer nCol "Number of columns"; input Modelica.Units.SI.Area[:] AArray "Vector of areas"; input Modelica.Units.SI.Area[nCol] AExt "Vector of exterior wall areas"; input Modelica.Units.SI.Area[nCol] AWin "Vector of window areas"; output Real[nRow,nCol] splitFacValues "Split factor values for ThermSplitter"; protected Modelica.Units.SI.Area ATot=sum(AArray) "Total area"; Integer j=1 "Row counter"; Integer k=1 "Column counter"; Integer l=1 "AArray counter"; algorithm for A in AArray loop if A > 0 then k :=1; if l == 1 then for AWall in AExt loop splitFacValues[j,k] :=(A-AWall)/(ATot-AWall-AWin[k]); k := k + 1; end for; elseif l == 2 then for AWall in AExt loop splitFacValues[j,k] :=(A-AWin[k])/(ATot-AWall-AWin[k]); k := k + 1; end for; else for AWall in AExt loop splitFacValues[j,k] :=A/(ATot-AWall-AWin[k]); k := k + 1; end for; end if; j :=j + 1; end if; l :=l + 1; end for; end splitFacVal;