modelModular

Grey-box model for reversible and non-reversible chillers

Extends from Buildings.Fluid.HeatPumps.ModularReversible.BaseClasses.PartialReversibleRefrigerantMachine (Model for reversible heat pumps and chillers with a refrigerant cycle).

Information

Model of a reversible, modular chiller. This models allows combining any of the available modules for refrigerant heating or cooling cycles, inertias, heat losses, and safety controls. All features are optional.

Adding to the partial model ( Buildings.Fluid.HeatPumps.ModularReversible.BaseClasses.PartialReversibleRefrigerantMachine), this model has the coo signal to choose the operation mode of the chiller.

For more information, see Buildings.Fluid.HeatPumps.ModularReversible.UsersGuide.

Parameters

Type	Name	Default	Description
Boolean	use_rev (from PartialReversibleRefrigerantMachine)	true	=true if the chiller or heat pump is reversible
Buildings.Fluid.HeatPumps.ModularReversible.Controls.Safety.Data.Wuellhorst2021	safCtrPar (from PartialReversibleRefrigerantMachine)
Modelica.Units.SI.Density	rhoCon (from PartialReversibleRefrigerantMachine)	MediumCon.density(staCon_nominal)	Condenser medium density
Modelica.Units.SI.SpecificHeatCapacity	cpCon (from PartialReversibleRefrigerantMachine)	MediumCon.specificHeatCapacityCp(staCon_nominal)	Condenser medium specific heat capacity
Modelica.Units.SI.Density	rhoEva (from PartialReversibleRefrigerantMachine)	MediumEva.density(staEva_nominal)	Evaporator medium density
Modelica.Units.SI.SpecificHeatCapacity	cpEva (from PartialReversibleRefrigerantMachine)	MediumEva.specificHeatCapacityCp(staEva_nominal)	Evaporator medium specific heat capacity
Assumptions
Boolean	allowFlowReversal1 (from PartialFourPort)	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 1
Boolean	allowFlowReversal2 (from PartialFourPort)	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 2
Nominal condition
Modelica.Units.SI.MassFlowRate	m1_flow_nominal (from PartialFourPortInterface)		Nominal mass flow rate
Modelica.Units.SI.MassFlowRate	m2_flow_nominal (from PartialFourPortInterface)		Nominal mass flow rate
Modelica.Units.SI.HeatFlowRate	PEle_nominal (from PartialReversibleRefrigerantMachine)		Nominal electrical power consumption
Modelica.Units.SI.HeatFlowRate	QCoo_flow_nominal		Nominal cooling capcaity
Modelica.Units.SI.Temperature	TEvaCoo_nominal		Nominal temperature of the cooled fluid during cooling mode
Modelica.Units.SI.Temperature	TConCoo_nominal		Nominal temperature of the heated fluid during cooling mode
Advanced
Medium1.MassFlowRate	m1_flow_small (from PartialFourPortInterface)	1E-4*abs(m1_flow_nominal)	Small mass flow rate for regularization of zero flow
Medium2.MassFlowRate	m2_flow_small (from PartialFourPortInterface)	1E-4*abs(m2_flow_nominal)	Small mass flow rate for regularization of zero flow
Boolean	allowDifferentDeviceIdentifiers (from PartialReversibleRefrigerantMachine)	false	if use_rev=true, device data for cooling and heating need to entered. Set allowDifferentDeviceIdentifiers=true to allow different device identifiers devIde
Boolean	calEff (from PartialReversibleRefrigerantMachine)	true	=false to disable efficiency calculation, may speed up the simulation
Real	limWarSca (from PartialReversibleRefrigerantMachine)	0.05	Allowed difference in scaling '\|scaFacHea - scaFacCoo\| / scaFacHea', if exceeded, a warning will be issued
Advanced › Diagnostics
Boolean	show_T (from PartialFourPortInterface)	false	= true, if actual temperature at port is computed
Real	ySet_small (from PartialReversibleRefrigerantMachine)	0.01	Threshold for relative speed for the device to be considered on
Safety control
Boolean	use_intSafCtr (from PartialReversibleRefrigerantMachine)	true	=true to enable internal safety control
Condenser › Dynamics
Modelica.Units.SI.Time	tauCon (from PartialReversibleRefrigerantMachine)	30	Condenser heat transfer time constant at nominal flow
Nominal condition - Pressure losses
Modelica.Units.SI.TemperatureDifference	dTCon_nominal (from PartialReversibleRefrigerantMachine)		Nominal temperature difference in condenser medium, used to calculate mass flow rate
Modelica.Units.SI.MassFlowRate	mCon_flow_nominal (from PartialReversibleRefrigerantMachine)		Nominal mass flow rate of the condenser medium
Modelica.Units.SI.PressureDifference	dpCon_nominal (from PartialReversibleRefrigerantMachine)		Pressure drop at nominal mass flow rate
Modelica.Units.SI.TemperatureDifference	dTEva_nominal (from PartialReversibleRefrigerantMachine)		Nominal temperature difference in evaporator medium, used to calculate mass flow rate
Modelica.Units.SI.MassFlowRate	mEva_flow_nominal (from PartialReversibleRefrigerantMachine)		Nominal mass flow rate of the evaporator medium
Modelica.Units.SI.PressureDifference	dpEva_nominal (from PartialReversibleRefrigerantMachine)		Pressure drop at nominal mass flow rate
Condenser › Flow resistance
Real	deltaMCon (from PartialReversibleRefrigerantMachine)	0.1	Fraction of nominal mass flow rate where transition to turbulent occurs
Real	nCon (from PartialReversibleRefrigerantMachine)	2	Flow exponent, n=1 for laminar, n=2 for turbulent
Condenser › Heat Losses
Boolean	use_conCap (from PartialReversibleRefrigerantMachine)	true	=true if using capacitor model for condenser heat loss estimation
Modelica.Units.SI.HeatCapacity	CCon (from PartialReversibleRefrigerantMachine)	0	Heat capacity of the condenser
Modelica.Units.SI.ThermalConductance	GConOut (from PartialReversibleRefrigerantMachine)	0	Outer thermal conductance for condenser heat loss calculations
Modelica.Units.SI.ThermalConductance	GConIns (from PartialReversibleRefrigerantMachine)	0	Inner thermal conductance for condenser heat loss calculations
Evaporator › Dynamics
Modelica.Units.SI.Time	tauEva (from PartialReversibleRefrigerantMachine)	30	Evaporator heat transfer time constant at nominal flow
Evaporator › Flow resistance
Real	deltaMEva (from PartialReversibleRefrigerantMachine)	0.1	Fraction of nominal mass flow rate where transition to turbulent occurs
Real	nEva (from PartialReversibleRefrigerantMachine)	2	Flow exponent, n=1 for laminar, n=2 for turbulent
Evaporator › Heat Losses
Boolean	use_evaCap (from PartialReversibleRefrigerantMachine)	true	=true if using capacitor model for evaporator heat loss estimation
Modelica.Units.SI.HeatCapacity	CEva (from PartialReversibleRefrigerantMachine)	0	Heat capacity of the evaporator
Modelica.Units.SI.ThermalConductance	GEvaOut (from PartialReversibleRefrigerantMachine)	0	Outer thermal conductance for evaporator heat loss calculations
Modelica.Units.SI.ThermalConductance	GEvaIns (from PartialReversibleRefrigerantMachine)	0	Inner thermal conductance for evaporator heat loss calculations
Assumptions › Evaporator
Boolean	allowFlowReversalEva (from PartialReversibleRefrigerantMachine)	true	= false to simplify equations, assuming, but not enforcing, no flow reversal
Assumptions › Condenser
Boolean	allowFlowReversalCon (from PartialReversibleRefrigerantMachine)	true	= false to simplify equations, assuming, but not enforcing, no flow reversal
Initialization › Parameters
Modelica.Blocks.Types.Init	initType (from PartialReversibleRefrigerantMachine)	Modelica.Blocks.Types.Init.InitialState	Type of initialization for refrigerant cycle dynamics (InitialState and InitialOutput are identical)
Initialization › Condenser
Modelica.Media.Interfaces.Types.AbsolutePressure	pCon_start (from PartialReversibleRefrigerantMachine)	MediumCon.p_default	Start value of pressure
Modelica.Media.Interfaces.Types.Temperature	TCon_start (from PartialReversibleRefrigerantMachine)	MediumCon.T_default	Start value of temperature
Modelica.Units.SI.Temperature	TConCap_start (from PartialReversibleRefrigerantMachine)	MediumCon.T_default	Initial temperature of heat capacity of condenser
Modelica.Media.Interfaces.Types.MassFraction[MediumCon.nX]	XCon_start (from PartialReversibleRefrigerantMachine)	MediumCon.X_default	Start value of mass fractions m_i/m
Initialization › Evaporator
Modelica.Media.Interfaces.Types.AbsolutePressure	pEva_start (from PartialReversibleRefrigerantMachine)	MediumEva.p_default	Start value of pressure
Modelica.Media.Interfaces.Types.Temperature	TEva_start (from PartialReversibleRefrigerantMachine)	MediumEva.T_default	Start value of temperature
Modelica.Units.SI.Temperature	TEvaCap_start (from PartialReversibleRefrigerantMachine)	MediumEva.T_default	Initial temperature of heat capacity at evaporator
Modelica.Media.Interfaces.Types.MassFraction[MediumEva.nX]	XEva_start (from PartialReversibleRefrigerantMachine)	MediumEva.X_default	Start value of mass fractions m_i/m
Dynamics › Equation
Modelica.Fluid.Types.Dynamics	energyDynamics (from PartialReversibleRefrigerantMachine)	Modelica.Fluid.Types.Dynamics.DynamicFreeInitial	Type of energy balance: dynamic (3 initialization options) or steady state (only affects fluid-models)
Advanced › Flow resistance
Boolean	from_dp (from PartialReversibleRefrigerantMachine)	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearized (from PartialReversibleRefrigerantMachine)	false	= true, use linear relation between m_flow and dp for any flow rate
Nominal condition - Heating
Modelica.Units.SI.HeatFlowRate	QHea_flow_nominal	0	Nominal heating capacity
Modelica.Units.SI.Temperature	TEvaHea_nominal		Nominal temperature of the heated fluid during heating mode
Modelica.Units.SI.Temperature	TConHea_nominal		Nominal temperature of the cooled fluid during heating mode

Connectors

Type	Name	Description
Modelica.Fluid.Interfaces.FluidPort_a	port_a1 (from PartialFourPort)	Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)
Modelica.Fluid.Interfaces.FluidPort_b	port_b1 (from PartialFourPort)	Fluid connector b1 (positive design flow direction is from port_a1 to port_b1)
Modelica.Fluid.Interfaces.FluidPort_a	port_a2 (from PartialFourPort)	Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
Modelica.Fluid.Interfaces.FluidPort_b	port_b2 (from PartialFourPort)	Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)
Modelica.Blocks.Interfaces.RealInput	ySet (from PartialReversibleRefrigerantMachine)	Relative compressor speed between 0 and 1
Modelica.Blocks.Interfaces.RealInput	TEvaAmb (from PartialReversibleRefrigerantMachine)	Ambient temperature on the evaporator side
Modelica.Blocks.Interfaces.RealInput	TConAmb (from PartialReversibleRefrigerantMachine)	Ambient temperature on the condenser side
Modelica.Blocks.Interfaces.RealOutput	QCon_flow (from PartialReversibleRefrigerantMachine)	Actual heating heat flow rate added to fluid 1
Modelica.Blocks.Interfaces.RealOutput	P (from PartialReversibleRefrigerantMachine)	Electric power consumed by compressor
Modelica.Blocks.Interfaces.RealOutput	QEva_flow (from PartialReversibleRefrigerantMachine)	Actual cooling heat flow rate removed from fluid 2
Modelica.Blocks.Interfaces.RealOutput	EER (from PartialReversibleRefrigerantMachine)	Energy efficieny ratio
Modelica.Blocks.Interfaces.RealOutput	COP (from PartialReversibleRefrigerantMachine)	Coefficient of performance
Modelica.Blocks.Interfaces.BooleanInput	coo	=true for cooling, =false for heating

Components

Type	Name	Default	Description
Medium1.MassFlowRate	m1_flow (from PartialFourPortInterface)	port_a1.m_flow	Mass flow rate from port_a1 to port_b1 (m1_flow > 0 is design flow direction)
Modelica.Units.SI.PressureDifference	dp1 (from PartialFourPortInterface)	port_a1.p - port_b1.p	Pressure difference between port_a1 and port_b1
Medium2.MassFlowRate	m2_flow (from PartialFourPortInterface)	port_a2.m_flow	Mass flow rate from port_a2 to port_b2 (m2_flow > 0 is design flow direction)
Modelica.Units.SI.PressureDifference	dp2 (from PartialFourPortInterface)	port_a2.p - port_b2.p	Pressure difference between port_a2 and port_b2
Medium1.ThermodynamicState	sta_a1 (from PartialFourPortInterface)	if allowFlowReversal1 then Medium1.setState_phX(port_a1.p, noEvent(actualStream(port_a1.h_outflow)), noEvent(actualStream(port_a1.Xi_outflow))) else Medium1.setState_phX(port_a1.p, inStream(port_a1.h_outflow), inStream(port_a1.Xi_outflow))	Medium properties in port_a1
Medium1.ThermodynamicState	sta_b1 (from PartialFourPortInterface)	if allowFlowReversal1 then Medium1.setState_phX(port_b1.p, noEvent(actualStream(port_b1.h_outflow)), noEvent(actualStream(port_b1.Xi_outflow))) else Medium1.setState_phX(port_b1.p, port_b1.h_outflow, port_b1.Xi_outflow)	Medium properties in port_b1
Medium2.ThermodynamicState	sta_a2 (from PartialFourPortInterface)	if allowFlowReversal2 then Medium2.setState_phX(port_a2.p, noEvent(actualStream(port_a2.h_outflow)), noEvent(actualStream(port_a2.Xi_outflow))) else Medium2.setState_phX(port_a2.p, inStream(port_a2.h_outflow), inStream(port_a2.Xi_outflow))	Medium properties in port_a2
Medium2.ThermodynamicState	sta_b2 (from PartialFourPortInterface)	if allowFlowReversal2 then Medium2.setState_phX(port_b2.p, noEvent(actualStream(port_b2.h_outflow)), noEvent(actualStream(port_b2.Xi_outflow))) else Medium2.setState_phX(port_b2.p, port_b2.h_outflow, port_b2.Xi_outflow)	Medium properties in port_b2
PartialModularRefrigerantCycle	refCyc (from PartialReversibleRefrigerantMachine)
Modelica.Units.SI.HeatFlowRate	Q1_flow (from PartialReversibleRefrigerantMachine)	QCon_flow	Heat transferred into the medium 1
Modelica.Units.SI.HeatFlowRate	Q2_flow (from PartialReversibleRefrigerantMachine)	QEva_flow	Heat transferred into the medium 2
Buildings.Fluid.HeatPumps.ModularReversible.BaseClasses.EvaporatorCondenserWithCapacity	con (from PartialReversibleRefrigerantMachine)		Heat exchanger model for the condenser
Buildings.Fluid.HeatPumps.ModularReversible.BaseClasses.EvaporatorCondenserWithCapacity	eva (from PartialReversibleRefrigerantMachine)		Heat exchanger model for the evaporator
Buildings.HeatTransfer.Sources.PrescribedTemperature	varTOutEva (from PartialReversibleRefrigerantMachine)		Forces heat losses according to ambient temperature
Buildings.HeatTransfer.Sources.PrescribedTemperature	varTOutCon (from PartialReversibleRefrigerantMachine)		Forces heat losses according to ambient temperature
Buildings.Fluid.HeatPumps.ModularReversible.Controls.Safety.Safety	safCtr (from PartialReversibleRefrigerantMachine)		Safety control models
Buildings.Fluid.Sensors.MassFlowRate	mEva_flow (from PartialReversibleRefrigerantMachine)		Mass flow sensor at the evaporator
Buildings.Fluid.Sensors.MassFlowRate	mCon_flow (from PartialReversibleRefrigerantMachine)		Mass flow sensor at the condenser
RefrigerantCycleInertia	refCycIneCon (from PartialReversibleRefrigerantMachine)		Inertia model for condenser side
RefrigerantCycleInertia	refCycIneEva (from PartialReversibleRefrigerantMachine)		Inertia model for evaporator side
Modelica.Blocks.Sources.RealExpression	senTConIn (from PartialReversibleRefrigerantMachine)		Real expression for condenser inlet temperature
Modelica.Blocks.Sources.RealExpression	senTEvaIn (from PartialReversibleRefrigerantMachine)		Real expression for evaporator inlet temperature
Buildings.Fluid.HeatPumps.ModularReversible.BaseClasses.CalculateEfficiency	eff (from PartialReversibleRefrigerantMachine)		Calculate efficiencies of device
Modelica.Blocks.Sources.BooleanConstant	conCoo		Locks the device in cooling mode if designated to be not reversible
Modelica.Blocks.Logical.Not	notCoo		Not cooling is heating
Modelica.Blocks.Logical.Hysteresis	hys		Outputs whether the device is on based on the relative speed

Name	Description
RefrigerantCycleChillerCooling
RefrigerantCycleChillerHeating

Revisions

May 23, 2025, by Michael Wetter:
Added assertion against wrong parameterization.
This is for IBPSA #2013.
February 25, 2025, by Antoine Gautier:
Added hysteresis that was removed from base class.
This is for IBPSA #1977.
May 2, 2024, by Michael Wetter:
Refactored check for device identifiers.
This is for IBPSA, #1576.
May 22, 2019, by Julian Matthes:
First implementation (see issue AixLib #715)