Buildings.Fluid.DXSystems.Cooling.WaterSource
Water source DX coils
Information
This package contains water source DX coil models, including single-speed, multi-speed, and variable-speed DX coil models.
Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).
Package Content
| Name | Description |
|---|---|
 MultiStage
|
Multi speed water source DX coils |
 SingleSpeed
|
Single speed water source DX coils |
 VariableSpeed
|
Variable speed water source DX coils |
 Data
|
Package with performance data for water source DX coils |
 Examples
|
Package with example of water source DX cooling coil models |
| Validation
|
Collection of validation models |
Buildings.Fluid.DXSystems.Cooling.WaterSource.MultiStage
Multi speed water source DX coils
Information
This model can be used to simulate a water source DX cooling coil with multiple operating stages. Depending on the used performance curves, each stage could be a different compressor speed, or a different mode of operation, such as with or without hot gas reheat.
See Buildings.Fluid.DXSystems.Cooling.UsersGuide for an explanation of the model.
Extends from Buildings.Fluid.DXSystems.Cooling.BaseClasses.PartialWaterCooledDXCoil (Base class for water source DX coils).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| DXCoil | datCoi | redeclare Buildings.Fluid.DX... | Performance data |
| replaceable package MediumEva | PartialMedium | Medium for evaporator | |
| replaceable package MediumCon | PartialMedium | Medium for condenser | |
| Boolean | computeReevaporation | true | Set to true to compute reevaporation of water that accumulated on coil |
| Nominal condition | |||
| PressureDifference | dpEva_nominal | Pressure difference over evaporator at nominal flow rate [Pa] | |
| PressureDifference | dpCon_nominal | Pressure difference over condenser at nominal flow rate [Pa] | |
| Assumptions | |||
| Boolean | allowFlowReversalEva | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for evaporator |
| Boolean | allowFlowReversalCon | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for condenser |
| Flow resistance | |||
| Condenser | |||
| Boolean | from_dpEva | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistanceEva | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaMEva | 0.1 | Fraction of nominal flow rate where flow transitions to laminar [1] |
| Evaporator | |||
| Boolean | from_dpCon | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistanceCon | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaMCon | 0.1 | Fraction of nominal flow rate where flow transitions to laminar [1] |
| Dynamics | |||
| Condenser | |||
| Time | tauEva | 60 | Time constant at nominal flow rate (used if energyDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState) [s] |
| Evaporator | |||
| Time | tauCon | 60 | Time constant at nominal flow rate (used if energyDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState) [s] |
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Initialization | |||
| Medium 1 | |||
| AbsolutePressure | pEva_start | MediumEva.p_default | Start value of pressure [Pa] |
| Temperature | TEva_start | MediumEva.T_default | Start value of temperature [K] |
| MassFraction | XEva_start[MediumEva.nX] | MediumEva.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | CEva_start[MediumEva.nC] | fill(0, MediumEva.nC) | Start value of trace substances |
| ExtraProperty | CEva_nominal[MediumEva.nC] | fill(1E-2, MediumEva.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Medium 2 | |||
| AbsolutePressure | pCon_start | MediumCon.p_default | Start value of pressure [Pa] |
| Temperature | TCon_start | MediumCon.T_default | Start value of temperature [K] |
| MassFraction | XCon_start[MediumCon.nX] | MediumCon.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | CCon_start[MediumCon.nC] | fill(0, MediumCon.nC) | Start value of trace substances |
| ExtraProperty | CCon_nominal[MediumCon.nC] | fill(1E-2, MediumCon.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Advanced | |||
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| output RealOutput | P | Electrical power consumed by the unit [W] |
| output RealOutput | QEvaSen_flow | Sensible heat flow rate in evaporators [W] |
| output RealOutput | QEvaLat_flow | Latent heat flow rate in evaporators [W] |
| FluidPort_a | port_a | Fluid connector for evaporator inlet (positive design flow direction is from port_a1 to port_b1) |
| FluidPort_b | port_b | Fluid connector b1 (positive design flow direction is from port_a1 to port_b1) |
| FluidPort_a | portCon_a | Fluid connector a of condenser (positive design flow direction is from port_a2 to port_b2) |
| FluidPort_b | portCon_b | Fluid connector b of condenser (positive design flow direction is from port_a2 to port_b2) |
| input IntegerInput | stage | Stage of cooling coil (0: off, 1: first stage, 2: second stage...) |
Modelica definition
model MultiStage "Multi speed water source DX coils"
extends Buildings.Fluid.DXSystems.Cooling.BaseClasses.PartialWaterCooledDXCoil
( redeclare final Buildings.Fluid.DXSystems.Cooling.AirSource.MultiStage eva);
Modelica.Blocks.Interfaces.IntegerInput stage
"Stage of cooling coil (0: off, 1: first stage, 2: second stage...)";
equation
connect(eva.stage, stage);
end MultiStage;
Buildings.Fluid.DXSystems.Cooling.WaterSource.SingleSpeed
Single speed water source DX coils
Information
This model can be used to simulate a water source DX cooling coil with single speed compressor.
See Buildings.Fluid.DXSystems.Cooling.UsersGuide for an explanation of the model.
Extends from Buildings.Fluid.DXSystems.Cooling.BaseClasses.PartialWaterCooledDXCoil (Base class for water source DX coils).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| DXCoil | datCoi | redeclare Buildings.Fluid.DX... | Performance data |
| replaceable package MediumEva | PartialMedium | Medium for evaporator | |
| replaceable package MediumCon | PartialMedium | Medium for condenser | |
| Boolean | computeReevaporation | true | Set to true to compute reevaporation of water that accumulated on coil |
| Nominal condition | |||
| PressureDifference | dpEva_nominal | Pressure difference over evaporator at nominal flow rate [Pa] | |
| PressureDifference | dpCon_nominal | Pressure difference over condenser at nominal flow rate [Pa] | |
| Assumptions | |||
| Boolean | allowFlowReversalEva | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for evaporator |
| Boolean | allowFlowReversalCon | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for condenser |
| Flow resistance | |||
| Condenser | |||
| Boolean | from_dpEva | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistanceEva | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaMEva | 0.1 | Fraction of nominal flow rate where flow transitions to laminar [1] |
| Evaporator | |||
| Boolean | from_dpCon | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistanceCon | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaMCon | 0.1 | Fraction of nominal flow rate where flow transitions to laminar [1] |
| Dynamics | |||
| Condenser | |||
| Time | tauEva | 60 | Time constant at nominal flow rate (used if energyDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState) [s] |
| Evaporator | |||
| Time | tauCon | 60 | Time constant at nominal flow rate (used if energyDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState) [s] |
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Initialization | |||
| Medium 1 | |||
| AbsolutePressure | pEva_start | MediumEva.p_default | Start value of pressure [Pa] |
| Temperature | TEva_start | MediumEva.T_default | Start value of temperature [K] |
| MassFraction | XEva_start[MediumEva.nX] | MediumEva.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | CEva_start[MediumEva.nC] | fill(0, MediumEva.nC) | Start value of trace substances |
| ExtraProperty | CEva_nominal[MediumEva.nC] | fill(1E-2, MediumEva.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Medium 2 | |||
| AbsolutePressure | pCon_start | MediumCon.p_default | Start value of pressure [Pa] |
| Temperature | TCon_start | MediumCon.T_default | Start value of temperature [K] |
| MassFraction | XCon_start[MediumCon.nX] | MediumCon.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | CCon_start[MediumCon.nC] | fill(0, MediumCon.nC) | Start value of trace substances |
| ExtraProperty | CCon_nominal[MediumCon.nC] | fill(1E-2, MediumCon.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Advanced | |||
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| output RealOutput | P | Electrical power consumed by the unit [W] |
| output RealOutput | QEvaSen_flow | Sensible heat flow rate in evaporators [W] |
| output RealOutput | QEvaLat_flow | Latent heat flow rate in evaporators [W] |
| FluidPort_a | port_a | Fluid connector for evaporator inlet (positive design flow direction is from port_a1 to port_b1) |
| FluidPort_b | port_b | Fluid connector b1 (positive design flow direction is from port_a1 to port_b1) |
| FluidPort_a | portCon_a | Fluid connector a of condenser (positive design flow direction is from port_a2 to port_b2) |
| FluidPort_b | portCon_b | Fluid connector b of condenser (positive design flow direction is from port_a2 to port_b2) |
| input BooleanInput | on | Set to true to enable compressor, or false to disable compressor |
Modelica definition
model SingleSpeed "Single speed water source DX coils"
extends Buildings.Fluid.DXSystems.Cooling.BaseClasses.PartialWaterCooledDXCoil
(
redeclare Buildings.Fluid.DXSystems.Cooling.AirSource.SingleSpeed eva);
Modelica.Blocks.Interfaces.BooleanInput on
"Set to true to enable compressor, or false to disable compressor";
equation
connect(eva.on, on);
end SingleSpeed;
Buildings.Fluid.DXSystems.Cooling.WaterSource.VariableSpeed
Variable speed water source DX coils
Information
This model can be used to simulate a water source DX cooling coil with variable speed compressor.
See Buildings.Fluid.DXSystems.Cooling.UsersGuide for an explanation of the model.
Extends from Buildings.Fluid.DXSystems.Cooling.BaseClasses.PartialWaterCooledDXCoil (Base class for water source DX coils).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| DXCoil | datCoi | redeclare Buildings.Fluid.DX... | Performance data |
| replaceable package MediumEva | PartialMedium | Medium for evaporator | |
| replaceable package MediumCon | PartialMedium | Medium for condenser | |
| Boolean | computeReevaporation | true | Set to true to compute reevaporation of water that accumulated on coil |
| Real | minSpeRat | Minimum speed ratio | |
| Real | speRatDeaBan | 0.05 | Deadband for minimum speed ratio |
| Nominal condition | |||
| PressureDifference | dpEva_nominal | Pressure difference over evaporator at nominal flow rate [Pa] | |
| PressureDifference | dpCon_nominal | Pressure difference over condenser at nominal flow rate [Pa] | |
| Assumptions | |||
| Boolean | allowFlowReversalEva | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for evaporator |
| Boolean | allowFlowReversalCon | true | = false to simplify equations, assuming, but not enforcing, no flow reversal for condenser |
| Flow resistance | |||
| Condenser | |||
| Boolean | from_dpEva | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistanceEva | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaMEva | 0.1 | Fraction of nominal flow rate where flow transitions to laminar [1] |
| Evaporator | |||
| Boolean | from_dpCon | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistanceCon | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaMCon | 0.1 | Fraction of nominal flow rate where flow transitions to laminar [1] |
| Dynamics | |||
| Condenser | |||
| Time | tauEva | 60 | Time constant at nominal flow rate (used if energyDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState) [s] |
| Evaporator | |||
| Time | tauCon | 60 | Time constant at nominal flow rate (used if energyDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState) [s] |
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Initialization | |||
| Medium 1 | |||
| AbsolutePressure | pEva_start | MediumEva.p_default | Start value of pressure [Pa] |
| Temperature | TEva_start | MediumEva.T_default | Start value of temperature [K] |
| MassFraction | XEva_start[MediumEva.nX] | MediumEva.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | CEva_start[MediumEva.nC] | fill(0, MediumEva.nC) | Start value of trace substances |
| ExtraProperty | CEva_nominal[MediumEva.nC] | fill(1E-2, MediumEva.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Medium 2 | |||
| AbsolutePressure | pCon_start | MediumCon.p_default | Start value of pressure [Pa] |
| Temperature | TCon_start | MediumCon.T_default | Start value of temperature [K] |
| MassFraction | XCon_start[MediumCon.nX] | MediumCon.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | CCon_start[MediumCon.nC] | fill(0, MediumCon.nC) | Start value of trace substances |
| ExtraProperty | CCon_nominal[MediumCon.nC] | fill(1E-2, MediumCon.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Advanced | |||
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| output RealOutput | P | Electrical power consumed by the unit [W] |
| output RealOutput | QEvaSen_flow | Sensible heat flow rate in evaporators [W] |
| output RealOutput | QEvaLat_flow | Latent heat flow rate in evaporators [W] |
| FluidPort_a | port_a | Fluid connector for evaporator inlet (positive design flow direction is from port_a1 to port_b1) |
| FluidPort_b | port_b | Fluid connector b1 (positive design flow direction is from port_a1 to port_b1) |
| FluidPort_a | portCon_a | Fluid connector a of condenser (positive design flow direction is from port_a2 to port_b2) |
| FluidPort_b | portCon_b | Fluid connector b of condenser (positive design flow direction is from port_a2 to port_b2) |
| input RealInput | speRat | Speed ratio [1] |
Modelica definition
model VariableSpeed "Variable speed water source DX coils"
extends Buildings.Fluid.DXSystems.Cooling.BaseClasses.PartialWaterCooledDXCoil
( redeclare final Buildings.Fluid.DXSystems.Cooling.AirSource.VariableSpeed
eva(
final minSpeRat=minSpeRat,
final speRatDeaBan=speRatDeaBan));
parameter Real minSpeRat(min=0,max=1) "Minimum speed ratio";
parameter Real speRatDeaBan= 0.05 "Deadband for minimum speed ratio";
Modelica.Blocks.Interfaces.RealInput speRat(
min=0,
max=1,
final unit="1")
"Speed ratio";
equation
connect(speRat, eva.speRat);
end VariableSpeed;