Buildings.Fluid.HeatPumps

Information

This package contains component models for heat pumps.

Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).

Package Content

Name	Description
Carnot_TCon	Heat pump with prescribed condenser leaving temperature and performance curve adjusted based on Carnot efficiency
Carnot_y	Reversible heat pump with performance curve adjusted based on Carnot efficiency
ReciprocatingWaterToWater	Model for a reciprocating water to water heat pump
ScrollWaterToWater	Model for a scroll water to water heat pump
Calibration	Package for calibration of heat pump models
Compressors	Package with compressor models
Data	Package with model parameters for heat pumps
Examples	Collection of models that illustrate model use and test models
Validation	Collection of models that validate the heat pump models
BaseClasses	Package with base classes for Buildings.Fluid.HeatPumps

Buildings.Fluid.HeatPumps.Carnot_TCon

Heat pump with prescribed condenser leaving temperature and performance curve adjusted based on Carnot efficiency

Buildings.Fluid.HeatPumps.Carnot_TCon

Information

This is a model of a heat pump whose coefficient of performance COP changes with temperatures in the same way as the Carnot efficiency changes. The control input is the setpoint of the condenser leaving temperature, which is met exactly at steady state if the heat pump has sufficient capacity.

The model allows to either specify the Carnot effectivness η_Carnot,0, or a COP₀ at the nominal conditions, together with the evaporator temperature T_eva,0 and the condenser temperature T_con,0, in which case the model computes the Carnot effectivness as

η_Carnot,0 = COP₀ ⁄ (T_con,0 ⁄ (T_con,0-T_eva,0)).

The heat pump COP is computed as the product

COP = η_Carnot,0 COP_Carnot η_PL,

where COP_Carnot is the Carnot efficiency and η_PL is a polynomial in heating part load ratio y_PL that can be used to take into account a change in COP at part load conditions. This polynomial has the form

η_PL = a₁ + a₂ y_PL + a₃ y_PL² + ...

where the coefficients a_i are declared by the parameter a.

On the Dynamics tag, the model can be parametrized to compute a transient or steady-state response. The transient response of the model is computed using a first order differential equation for the evaporator and condenser fluid volumes. The heat pump outlet temperatures are equal to the temperatures of these lumped volumes.

Typical use and important parameters

When using this component, make sure that the condenser has sufficient mass flow rate. Based on the evaporator mass flow rate, temperature difference and the efficiencies, the model computes how much heat will be removed by to the evaporator. If the mass flow rate is too small, very low outlet temperatures can result, possibly below freezing.

The condenser heat flow rate QCon_flow_nominal is used to assign the default value for the mass flow rates, which are used for the pressure drop calculations. It is also used to compute the part load efficiency. Hence, make sure that QCon_flow_nominal is set to a reasonable value.

The maximum heating capacity is set by the parameter QCon_flow_max, which is by default set to infinity.

The coefficient of performance depends on the evaporator and condenser leaving temperature since otherwise the second law of thermodynamics may be violated.

Notes

For a similar model that can be used as a chiller, see Buildings.Fluid.Chillers.Examples.Carnot_TEva.

Extends from Buildings.Fluid.Chillers.BaseClasses.PartialCarnot_T (Partial model for chiller with performance curve adjusted based on Carnot efficiency).

Parameters

Type	Name	Default	Description
replaceable package Medium1		PartialMedium	Medium 1 in the component
replaceable package Medium2		PartialMedium	Medium 2 in the component
HeatFlowRate	QCon_flow_max	Modelica.Constants.inf	Maximum heat flow rate for heating (positive) [W]
Nominal condition
MassFlowRate	m1_flow_nominal	QCon_flow_nominal/cp1_defaul...	Nominal mass flow rate [kg/s]
MassFlowRate	m2_flow_nominal	QEva_flow_nominal/cp2_defaul...	Nominal mass flow rate [kg/s]
HeatFlowRate	QEva_flow_nominal	-QCon_flow_nominal*(COP_nomi...	Nominal cooling heat flow rate (QEva_flow_nominal < 0) [W]
HeatFlowRate	QCon_flow_nominal		Nominal heating flow rate [W]
TemperatureDifference	dTEva_nominal	-10	Temperature difference evaporator outlet-inlet [K]
TemperatureDifference	dTCon_nominal	10	Temperature difference condenser outlet-inlet [K]
Pressure	dp1_nominal		Pressure difference over condenser [Pa]
Pressure	dp2_nominal		Pressure difference over evaporator [Pa]
Efficiency
Boolean	use_eta_Carnot_nominal	true	Set to true to use Carnot effectiveness etaCarnot_nominal rather than COP_nominal
Real	etaCarnot_nominal	COP_nominal/(TUse_nominal/(T...	Carnot effectiveness (=COP/COP_Carnot) used if use_eta_Carnot_nominal = true [1]
Real	COP_nominal	etaCarnot_nominal*TUse_nomin...	Coefficient of performance at TEva_nominal and TCon_nominal, used if use_eta_Carnot_nominal = false [1]
Temperature	TCon_nominal	303.15	Condenser temperature used to compute COP_nominal if use_eta_Carnot_nominal=false [K]
Temperature	TEva_nominal	278.15	Evaporator temperature used to compute COP_nominal if use_eta_Carnot_nominal=false [K]
Real	a[:]	{1}	Coefficients for efficiency curve (need p(a=a, yPL=1)=1)
Assumptions
Boolean	allowFlowReversal1	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 1
Boolean	allowFlowReversal2	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 2
Advanced
MassFlowRate	m1_flow_small	1E-4*abs(m1_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
MassFlowRate	m2_flow_small	1E-4*abs(m2_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Boolean	homotopyInitialization	true	= true, use homotopy method
Diagnostics
Boolean	show_T	false	= true, if actual temperature at port is computed
Flow resistance
Condenser
Boolean	from_dp1	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance1	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM1	0.1	Fraction of nominal flow rate where flow transitions to laminar [1]
Evaporator
Boolean	from_dp2	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance2	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM2	0.1	Fraction of nominal flow rate where flow transitions to laminar [1]
Dynamics
Condenser
Time	tau1	60	Time constant at nominal flow rate (used if energyDynamics1 <> Modelica.Fluid.Types.Dynamics.SteadyState) [s]
Temperature	T1_start	Medium1.T_default	Initial or guess value of set point [K]
Evaporator
Time	tau2	60	Time constant at nominal flow rate (used if energyDynamics2 <> Modelica.Fluid.Types.Dynamics.SteadyState) [s]
Temperature	T2_start	Medium2.T_default	Initial or guess value of set point [K]
Evaporator and condenser
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Type of energy balance: dynamic (3 initialization options) or steady state

Connectors

Type	Name	Description
FluidPort_a	port_a1	Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_b	port_b1	Fluid connector b1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_a	port_a2	Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
FluidPort_b	port_b2	Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)
output RealOutput	QCon_flow	Actual heating heat flow rate added to fluid 1 [W]
output RealOutput	P	Electric power consumed by compressor [W]
output RealOutput	QEva_flow	Actual cooling heat flow rate removed from fluid 2 [W]
input RealInput	TSet	Condenser leaving water temperature [K]

Modelica definition

model Carnot_TCon "Heat pump with prescribed condenser leaving temperature and performance curve adjusted based on Carnot efficiency" extends Buildings.Fluid.Chillers.BaseClasses.PartialCarnot_T( final COP_is_for_cooling = false, final QEva_flow_nominal = -QCon_flow_nominal*(COP_nominal-1)/COP_nominal, PEle(y=QCon_flow/COP), redeclare HeatExchangers.HeaterCooler_T con( final from_dp=from_dp1, final dp_nominal=dp1_nominal, final linearizeFlowResistance=linearizeFlowResistance1, final deltaM=deltaM1, final Q_flow_maxHeat=QCon_flow_max, final Q_flow_maxCool=0, final tau=tau1, final T_start=T1_start, final energyDynamics=energyDynamics, final homotopyInitialization=homotopyInitialization), redeclare HeatExchangers.HeaterCooler_u eva( final from_dp=from_dp2, final dp_nominal=dp2_nominal, final linearizeFlowResistance=linearizeFlowResistance2, final deltaM=deltaM2, final tau=tau2, final T_start=T2_start, final energyDynamics=energyDynamics, final homotopyInitialization=homotopyInitialization, final Q_flow_nominal=QEva_flow_nominal)); parameter Modelica.SIunits.HeatFlowRate QCon_flow_max( min=0) = Modelica.Constants.inf "Maximum heat flow rate for heating (positive)"; Modelica.Blocks.Interfaces.RealInput TSet(unit="K") "Condenser leaving water temperature"; protected Modelica.Blocks.Math.Gain yEva(final k=1/QEva_flow_nominal) "Normalized evaporator heat flow rate"; Modelica.Blocks.Math.Add QEva_flow_internal(final k1=-1) "Heat removed by evaporator"; initial equation assert(QCon_flow_nominal > 0, "Parameter QCon_flow_nominal must be positive."); assert(COP_nominal > 1, "The nominal COP of a heat pump must be bigger than one."); equation connect(TSet, con.TSet); connect(con.Q_flow, QCon_flow); connect(QEva_flow_internal.u1, con.Q_flow); connect(QEva_flow_internal.u2, PEle.y); connect(QEva_flow_internal.y, yEva.u); connect(QEva_flow, QEva_flow_internal.y); connect(yEva.y, eva.u); end Carnot_TCon;

Buildings.Fluid.HeatPumps.Carnot_y

Reversible heat pump with performance curve adjusted based on Carnot efficiency

Buildings.Fluid.HeatPumps.Carnot_y

Information

This is model of a heat pump whose coefficient of performance COP changes with temperatures in the same way as the Carnot efficiency changes. The input signal y is the control signal for the compressor.

η_Carnot,0 = COP₀ ⁄ (T_con,0 ⁄ (T_con,0-T_eva,0)).

The heat pump COP is computed as the product

COP = η_Carnot,0 COP_Carnot η_PL,

where COP_Carnot is the Carnot efficiency and η_PL is a polynomial in the heating part load ratio y_PL that can be used to take into account a change in COP at part load conditions. This polynomial has the form

η_PL = a₁ + a₂ y_PL + a₃ y_PL² + ...

where the coefficients a_i are declared by the parameter a.

Typical use and important parameters

When using this component, make sure that the evaporator and the condenser have sufficient mass flow rate. Based on the mass flow rates, the compressor power, temperature difference and the efficiencies, the model computes how much heat will be added to the condenser and removed at the evaporator. If the mass flow rates are too small, very high temperature differences can result.

The maximum heating capacity is set by the parameter QCon_flow_max, which is by default set to infinity.

The coefficient of performance depends on the evaporator and condenser leaving temperature since otherwise the second law of thermodynamics may be violated.

Notes

For a similar model that can be used as a chiller, see Buildings.Fluid.Chillers.Carnot_y.

Extends from Buildings.Fluid.Chillers.BaseClasses.PartialCarnot_y (Partial chiller model with performance curve adjusted based on Carnot efficiency).

Parameters

Type	Name	Default	Description
replaceable package Medium1		PartialMedium	Medium 1 in the component
replaceable package Medium2		PartialMedium	Medium 2 in the component
Nominal condition
MassFlowRate	m1_flow_nominal	QCon_flow_nominal/cp1_defaul...	Nominal mass flow rate [kg/s]
MassFlowRate	m2_flow_nominal	QEva_flow_nominal/cp2_defaul...	Nominal mass flow rate [kg/s]
TemperatureDifference	dTEva_nominal	-10	Temperature difference evaporator outlet-inlet [K]
TemperatureDifference	dTCon_nominal	10	Temperature difference condenser outlet-inlet [K]
Pressure	dp1_nominal		Pressure difference over condenser [Pa]
Pressure	dp2_nominal		Pressure difference over evaporator [Pa]
Power	P_nominal		Nominal compressor power (at y=1) [W]
Efficiency
Boolean	use_eta_Carnot_nominal	true	Set to true to use Carnot effectiveness etaCarnot_nominal rather than COP_nominal
Real	etaCarnot_nominal	COP_nominal/(TUse_nominal/(T...	Carnot effectiveness (=COP/COP_Carnot) used if use_eta_Carnot_nominal = true [1]
Real	COP_nominal	etaCarnot_nominal*TUse_nomin...	Coefficient of performance at TEva_nominal and TCon_nominal, used if use_eta_Carnot_nominal = false [1]
Temperature	TCon_nominal	303.15	Condenser temperature used to compute COP_nominal if use_eta_Carnot_nominal=false [K]
Temperature	TEva_nominal	278.15	Evaporator temperature used to compute COP_nominal if use_eta_Carnot_nominal=false [K]
Real	a[:]	{1}	Coefficients for efficiency curve (need p(a=a, yPL=1)=1)
Assumptions
Boolean	allowFlowReversal1	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 1
Boolean	allowFlowReversal2	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 2
Advanced
MassFlowRate	m1_flow_small	1E-4*abs(m1_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
MassFlowRate	m2_flow_small	1E-4*abs(m2_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Boolean	homotopyInitialization	true	= true, use homotopy method
Diagnostics
Boolean	show_T	false	= true, if actual temperature at port is computed
Flow resistance
Condenser
Boolean	from_dp1	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance1	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM1	0.1	Fraction of nominal flow rate where flow transitions to laminar [1]
Evaporator
Boolean	from_dp2	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance2	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM2	0.1	Fraction of nominal flow rate where flow transitions to laminar [1]
Dynamics
Condenser
Time	tau1	60	Time constant at nominal flow rate (used if energyDynamics1 <> Modelica.Fluid.Types.Dynamics.SteadyState) [s]
Temperature	T1_start	Medium1.T_default	Initial or guess value of set point [K]
Evaporator
Time	tau2	60	Time constant at nominal flow rate (used if energyDynamics2 <> Modelica.Fluid.Types.Dynamics.SteadyState) [s]
Temperature	T2_start	Medium2.T_default	Initial or guess value of set point [K]
Evaporator and condenser
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Type of energy balance: dynamic (3 initialization options) or steady state

Connectors

Type	Name	Description
FluidPort_a	port_a1	Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_b	port_b1	Fluid connector b1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_a	port_a2	Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
FluidPort_b	port_b2	Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)
output RealOutput	QCon_flow	Actual heating heat flow rate added to fluid 1 [W]
output RealOutput	P	Electric power consumed by compressor [W]
output RealOutput	QEva_flow	Actual cooling heat flow rate removed from fluid 2 [W]
input RealInput	y	Part load ratio of compressor [1]

Modelica definition

model Carnot_y "Reversible heat pump with performance curve adjusted based on Carnot efficiency" extends Buildings.Fluid.Chillers.BaseClasses.PartialCarnot_y( final COP_is_for_cooling = false); initial equation assert(COP_nominal > 1, "The nominal COP of a heat pump must be bigger than one."); end Carnot_y;

Buildings.Fluid.HeatPumps.ReciprocatingWaterToWater

Model for a reciprocating water to water heat pump

Buildings.Fluid.HeatPumps.ReciprocatingWaterToWater

Information

Model for a water to water heat pump with a reciprocating compressor, as described in Jin (2002). The thermodynamic heat pump cycle is represented below.

The rate of heat transfered to the evaporator is given by:

Q̇_Eva = ṁ_ref ( h_Vap(T_Eva) - h_Liq(T_Con) ).

The power consumed by the compressor is given by a linear efficiency relation:

P = P_Theoretical / η + P_{Loss,constant}.

Heat transfer in the evaporator and condenser is calculated using an ε-NTU method, assuming constant refrigerant temperature and constant heat transfer coefficient between fluid and refrigerant.

Variable speed is acheived by multiplying the full load piston displacement by the normalized compressor speed. The power and heat transfer rates are forced to zero if the resulting heat pump state has higher evaporating pressure than condensing pressure.

Assumptions and limitations

The compression process is assumed isentropic. The thermal energy of superheating is ignored in the evaluation of the heat transfered to the refrigerant in the evaporator. There is no supercooling.

References

H. Jin. Parameter estimation based models of water source heat pumps. PhD Thesis. Oklahoma State University. Stillwater, Oklahoma, USA. 2012.

Extends from Buildings.Fluid.HeatPumps.BaseClasses.PartialWaterToWater (Partial model for water to water heat pumps and chillers).

Parameters

Type	Name	Default	Description
replaceable package Medium1		PartialMedium	Medium 1 in the component
replaceable package Medium2		PartialMedium	Medium 2 in the component
replaceable package ref		R410A	Refrigerant in the component
Boolean	enable_variable_speed	true	Set to true to allow modulating of compressor speed
Real	scaling_factor	1.0	Scaling factor for heat pump capacity
ThermalConductance	UACon	per.UACon*scaling_factor	Thermal conductance of condenser [W/K]
ThermalConductance	UAEva	per.UAEva*scaling_factor	Thermal conductance of evaporator [W/K]
Generic	per		Heat pump performance data
Nominal condition
MassFlowRate	m1_flow_nominal		Nominal mass flow rate [kg/s]
MassFlowRate	m2_flow_nominal		Nominal mass flow rate [kg/s]
PressureDifference	dp1_nominal		Pressure difference [Pa]
PressureDifference	dp2_nominal		Pressure difference [Pa]
Assumptions
Boolean	allowFlowReversal1	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 1
Boolean	allowFlowReversal2	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 2
Advanced
MassFlowRate	m1_flow_small	1E-4*abs(m1_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
MassFlowRate	m2_flow_small	1E-4*abs(m2_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Boolean	homotopyInitialization	true	= true, use homotopy method
Diagnostics
Boolean	show_T	false	= true, if actual temperature at port is computed
Flow resistance
Medium 1
Boolean	from_dp1	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance1	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM1	0.1	Fraction of nominal flow rate where flow transitions to laminar
Medium 2
Boolean	from_dp2	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance2	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM2	0.1	Fraction of nominal flow rate where flow transitions to laminar
Dynamics
Condenser
Time	tau1	60	Time constant at nominal flow rate (used if energyDynamics1 <> Modelica.Fluid.Types.Dynamics.SteadyState) [s]
Temperature	T1_start	Medium1.T_default	Initial or guess value of set point [K]
Evaporator
Time	tau2	60	Time constant at nominal flow rate (used if energyDynamics2 <> Modelica.Fluid.Types.Dynamics.SteadyState) [s]
Temperature	T2_start	Medium2.T_default	Initial or guess value of set point [K]
Evaporator and condenser
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Type of energy balance: dynamic (3 initialization options) or steady state

Connectors

Type	Name	Description
FluidPort_a	port_a1	Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_b	port_b1	Fluid connector b1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_a	port_a2	Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
FluidPort_b	port_b2	Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)
input RealInput	y	Modulating signal for compressor frequency, equal to 1 at full load condition [1]
input IntegerInput	stage	Current stage of the heat pump, equal to 1 at full load condition
output RealOutput	QCon_flow	Actual heating heat flow rate added to fluid 1 [W]
output RealOutput	P	Electric power consumed by compressor [W]
output RealOutput	QEva_flow	Actual cooling heat flow rate removed from fluid 2 [W]

Modelica definition

model ReciprocatingWaterToWater "Model for a reciprocating water to water heat pump" extends Buildings.Fluid.HeatPumps.BaseClasses.PartialWaterToWater( final UAEva=per.UAEva * scaling_factor, final UACon=per.UACon * scaling_factor, redeclare HeatPumps.Compressors.ReciprocatingCompressor com( redeclare final package ref=ref, pisDis=per.pisDis * scaling_factor, cleFac=per.cleFac, etaEle=per.etaEle, PLos=per.PLos * scaling_factor, pDro=per.pDro, dTSup=per.dTSup)); parameter Data.ReciprocatingWaterToWater.Generic per "Heat pump performance data"; end ReciprocatingWaterToWater;

Buildings.Fluid.HeatPumps.ScrollWaterToWater

Model for a scroll water to water heat pump

Buildings.Fluid.HeatPumps.ScrollWaterToWater

Information

Model for a water to water heat pump with a scroll compressor, as described in Jin (2002). The thermodynamic heat pump cycle is represented below.

The rate of heat transfered to the evaporator is given by:

Q̇_Eva = ṁ_ref ( h_Vap(T_Eva) - h_Liq(T_Con) ).

The power consumed by the compressor is given by a linear efficiency relation:

P = P_Theoretical / η + P_{Loss,constant}.

Heat transfer in the evaporator and condenser is calculated using an ε-NTU method, assuming constant refrigerant temperature and constant heat transfer coefficient between fluid and refrigerant.

Variable speed is achieved by multiplying the full load suction volume flow rate by the normalized compressor speed. The power and heat transfer rates are forced to zero if the resulting heat pump state has higher evaporating pressure than condensing pressure.

The model parameters are obtained by calibration of the heat pump model to manufacturer performance data. Calibrated model parameters for various heat pumps from different manufacturers are found in Buildings.Fluid.HeatPumps.Data.ScrollWaterToWater. The calibrated model is located in Buildings.Fluid.HeatPumps.Calibration.ScrollWaterToWater.

Assumptions and limitations

The compression process is assumed isentropic. The thermal energy of superheating is ignored in the evaluation of the heat transfered to the refrigerant in the evaporator. There is no supercooling.

References

H. Jin. Parameter estimation based models of water source heat pumps. PhD Thesis. Oklahoma State University. Stillwater, Oklahoma, USA. 2012.

Extends from Buildings.Fluid.HeatPumps.BaseClasses.PartialWaterToWater (Partial model for water to water heat pumps and chillers).

Parameters

Type	Name	Default	Description
replaceable package Medium1		PartialMedium	Medium 1 in the component
replaceable package Medium2		PartialMedium	Medium 2 in the component
replaceable package ref		R410A	Refrigerant in the component
Boolean	enable_variable_speed	true	Set to true to allow modulating of compressor speed
Real	scaling_factor	1.0	Scaling factor for heat pump capacity
ThermalConductance	UACon	datHeaPum.UACon*scaling_factor	Thermal conductance of condenser [W/K]
ThermalConductance	UAEva	datHeaPum.UAEva*scaling_factor	Thermal conductance of evaporator [W/K]
Generic	datHeaPum		Heat pump data
Nominal condition
MassFlowRate	m1_flow_nominal		Nominal mass flow rate [kg/s]
MassFlowRate	m2_flow_nominal		Nominal mass flow rate [kg/s]
PressureDifference	dp1_nominal		Pressure difference [Pa]
PressureDifference	dp2_nominal		Pressure difference [Pa]
Assumptions
Boolean	allowFlowReversal1	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 1
Boolean	allowFlowReversal2	true	= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 2
Advanced
MassFlowRate	m1_flow_small	1E-4*abs(m1_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
MassFlowRate	m2_flow_small	1E-4*abs(m2_flow_nominal)	Small mass flow rate for regularization of zero flow [kg/s]
Boolean	homotopyInitialization	true	= true, use homotopy method
Diagnostics
Boolean	show_T	false	= true, if actual temperature at port is computed
Flow resistance
Medium 1
Boolean	from_dp1	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance1	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM1	0.1	Fraction of nominal flow rate where flow transitions to laminar
Medium 2
Boolean	from_dp2	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Boolean	linearizeFlowResistance2	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM2	0.1	Fraction of nominal flow rate where flow transitions to laminar
Dynamics
Condenser
Time	tau1	60	Time constant at nominal flow rate (used if energyDynamics1 <> Modelica.Fluid.Types.Dynamics.SteadyState) [s]
Temperature	T1_start	Medium1.T_default	Initial or guess value of set point [K]
Evaporator
Time	tau2	60	Time constant at nominal flow rate (used if energyDynamics2 <> Modelica.Fluid.Types.Dynamics.SteadyState) [s]
Temperature	T2_start	Medium2.T_default	Initial or guess value of set point [K]
Evaporator and condenser
Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamic...	Type of energy balance: dynamic (3 initialization options) or steady state

Connectors

Type	Name	Description
FluidPort_a	port_a1	Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_b	port_b1	Fluid connector b1 (positive design flow direction is from port_a1 to port_b1)
FluidPort_a	port_a2	Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
FluidPort_b	port_b2	Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)
input RealInput	y	Modulating signal for compressor frequency, equal to 1 at full load condition [1]
input IntegerInput	stage	Current stage of the heat pump, equal to 1 at full load condition
output RealOutput	QCon_flow	Actual heating heat flow rate added to fluid 1 [W]
output RealOutput	P	Electric power consumed by compressor [W]
output RealOutput	QEva_flow	Actual cooling heat flow rate removed from fluid 2 [W]

Modelica definition

model ScrollWaterToWater "Model for a scroll water to water heat pump" extends Buildings.Fluid.HeatPumps.BaseClasses.PartialWaterToWater( final UAEva=datHeaPum.UAEva*scaling_factor, final UACon=datHeaPum.UACon*scaling_factor, redeclare HeatPumps.Compressors.ScrollCompressor com( redeclare final package ref = ref, final volRat=datHeaPum.volRat, final V_flow_nominal=datHeaPum.V_flow_nominal*scaling_factor, final leaCoe=datHeaPum.leaCoe*scaling_factor, final etaEle=datHeaPum.etaEle, final PLos=datHeaPum.PLos*scaling_factor, final dTSup=datHeaPum.dTSup)); parameter Buildings.Fluid.HeatPumps.Data.ScrollWaterToWater.Generic datHeaPum "Heat pump data"; end ScrollWaterToWater;