Buildings.Fluid.HeatExchangers.DXCoils.AirCooled
Air-cooled DX package unit
Information
This package contains air-cooled DX coil models, including single-speed, multi-stage, and variable-speed DX coil models.Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).
Package Content
Name | Description |
---|---|
MultiStage | Multi-stage DX cooling coil |
SingleSpeed | Single speed DX cooling coil |
VariableSpeed | Variable speed DX cooling coil |
Data | Package with performance data for DX cooling coil |
Examples | Package with example of DX cooling coil models |
Validation | Collection of validation models |
Buildings.Fluid.HeatExchangers.DXCoils.AirCooled.MultiStage
Multi-stage DX cooling coil
Information
This model can be used to simulate an air-cooled 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.HeatExchangers.DXCoils.UsersGuide for an explanation of the model.
Extends from Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.PartialDXCoil (Partial model for DX coil).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialCondensingGases | Medium in the component | |
Boolean | use_mCon_flow | false | Set to true to enable connector for the condenser mass flow rate |
String | substanceName | "water" | Name of species substance |
Nominal condition | |||
PressureDifference | dp_nominal | Pressure difference [Pa] | |
Assumptions | |||
Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
Advanced | |||
MassFlowRate | m_flow_small | 1E-4*abs(m_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 | |||
Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
Boolean | linearizeFlowResistance | false | = true, use linear relation between m_flow and dp for any flow rate |
Real | deltaM | 0.1 | Fraction of nominal flow rate where flow transitions to laminar |
Dynamics | |||
Nominal condition | |||
Time | tau | 30 | Time constant at nominal flow (if energyDynamics <> SteadyState) [s] |
Equations | |||
Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Dynamics | massDynamics | energyDynamics | Type of mass balance: dynamic (3 initialization options) or steady state |
Moisture balance | |||
Boolean | computeReevaporation | true | Set to true to compute reevaporation of water that accumulated on coil |
Initialization | |||
AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
Temperature | T_start | Medium.T_default | Start value of temperature [K] |
MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
Connectors
Type | Name | Description |
---|---|---|
FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
input RealInput | TConIn | Outside air dry bulb temperature for an air cooled condenser or wetbulb temperature for an evaporative cooled condenser [K] |
input RealInput | mCon_flow | Water mass flow rate for condenser [kg/s] |
output RealOutput | P | Electrical power consumed by the unit [W] |
output RealOutput | QSen_flow | Sensible heat flow rate [W] |
output RealOutput | QLat_flow | Latent heat flow rate [W] |
input IntegerInput | stage | Stage of cooling coil (0: off, 1: first stage, 2: second stage...) |
Modelica definition
Buildings.Fluid.HeatExchangers.DXCoils.AirCooled.SingleSpeed
Single speed DX cooling coil
Information
This model can be used to simulate an air-cooled DX cooling coil with single speed compressor.
See Buildings.Fluid.HeatExchangers.DXCoils.UsersGuide for an explanation of the model.
Extends from Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.PartialDXCoil (Partial model for DX coil).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialCondensingGases | Medium in the component | |
Boolean | use_mCon_flow | false | Set to true to enable connector for the condenser mass flow rate |
String | substanceName | "water" | Name of species substance |
Nominal condition | |||
PressureDifference | dp_nominal | Pressure difference [Pa] | |
Assumptions | |||
Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
Advanced | |||
MassFlowRate | m_flow_small | 1E-4*abs(m_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 | |||
Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
Boolean | linearizeFlowResistance | false | = true, use linear relation between m_flow and dp for any flow rate |
Real | deltaM | 0.1 | Fraction of nominal flow rate where flow transitions to laminar |
Dynamics | |||
Nominal condition | |||
Time | tau | 30 | Time constant at nominal flow (if energyDynamics <> SteadyState) [s] |
Equations | |||
Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Dynamics | massDynamics | energyDynamics | Type of mass balance: dynamic (3 initialization options) or steady state |
Moisture balance | |||
Boolean | computeReevaporation | true | Set to true to compute reevaporation of water that accumulated on coil |
Initialization | |||
AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
Temperature | T_start | Medium.T_default | Start value of temperature [K] |
MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
Connectors
Type | Name | Description |
---|---|---|
FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
input RealInput | TConIn | Outside air dry bulb temperature for an air cooled condenser or wetbulb temperature for an evaporative cooled condenser [K] |
input RealInput | mCon_flow | Water mass flow rate for condenser [kg/s] |
output RealOutput | P | Electrical power consumed by the unit [W] |
output RealOutput | QSen_flow | Sensible heat flow rate [W] |
output RealOutput | QLat_flow | Latent heat flow rate [W] |
input BooleanInput | on | Set to true to enable compressor, or false to disable compressor |
Modelica definition
Buildings.Fluid.HeatExchangers.DXCoils.AirCooled.VariableSpeed
Variable speed DX cooling coil
Information
This model can be used to simulate an air-cooled DX cooling coil with continuously variable speed compressors. The control input is the speed ratio. The coil will switch off if the speed ratio is below a minimum value.
See Buildings.Fluid.HeatExchangers.DXCoils.UsersGuide for an explanation of the model.
Extends from Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.PartialDXCoil (Partial model for DX coil).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialCondensingGases | Medium in the component | |
Boolean | use_mCon_flow | false | Set to true to enable connector for the condenser mass flow rate |
String | substanceName | "water" | Name of species substance |
Real | minSpeRat | minSpeRat( ... | Minimum speed ratio |
Real | speRatDeaBan | 0.05 | Deadband for minimum speed ratio |
Nominal condition | |||
PressureDifference | dp_nominal | Pressure difference [Pa] | |
Assumptions | |||
Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
Advanced | |||
MassFlowRate | m_flow_small | 1E-4*abs(m_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 | |||
Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
Boolean | linearizeFlowResistance | false | = true, use linear relation between m_flow and dp for any flow rate |
Real | deltaM | 0.1 | Fraction of nominal flow rate where flow transitions to laminar |
Dynamics | |||
Nominal condition | |||
Time | tau | 30 | Time constant at nominal flow (if energyDynamics <> SteadyState) [s] |
Equations | |||
Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Dynamics | massDynamics | energyDynamics | Type of mass balance: dynamic (3 initialization options) or steady state |
Moisture balance | |||
Boolean | computeReevaporation | true | Set to true to compute reevaporation of water that accumulated on coil |
Initialization | |||
AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
Temperature | T_start | Medium.T_default | Start value of temperature [K] |
MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
Connectors
Type | Name | Description |
---|---|---|
FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
input RealInput | TConIn | Outside air dry bulb temperature for an air cooled condenser or wetbulb temperature for an evaporative cooled condenser [K] |
input RealInput | mCon_flow | Water mass flow rate for condenser [kg/s] |
output RealOutput | P | Electrical power consumed by the unit [W] |
output RealOutput | QSen_flow | Sensible heat flow rate [W] |
output RealOutput | QLat_flow | Latent heat flow rate [W] |
input RealInput | speRat | Speed ratio |