Buildings.Fluid.DXSystems.Heating.AirSource.Data.Generic

Package with generic performance curves

Information

This package contains performance curves for the heat transfer capacity and the EIR of air source DX heating coils.

The data are described in Buildings.Fluid.DXSystems.Heating.AirSource.Data.Generic.DXCoil.

Extends from Modelica.Icons.MaterialPropertiesPackage (Icon for package containing property classes).

Package Content

Name Description
Buildings.Fluid.DXSystems.Heating.AirSource.Data.Generic.DXCoil DXCoil Performance record for a DX Heating DXCoil with one or multiple stages
Buildings.Fluid.DXSystems.Heating.AirSource.Data.Generic.BaseClasses BaseClasses Package with base classes for performance data

Buildings.Fluid.DXSystems.Heating.AirSource.Data.Generic.DXCoil Buildings.Fluid.DXSystems.Heating.AirSource.Data.Generic.DXCoil

Performance record for a DX Heating DXCoil with one or multiple stages

Information

This record declares the performance data for the air source DX heating coil model. The performance data are structured as follows:

It consists of the following fields:

  nSta      - Number of stages. Set to 1 for single speed coil,
              2 for dual-speed (or dual stage coils), etc.
  minSpeRat - Minimum speed ratio, used only for variable speed coils.
  sta       - Array of records with one performance curve for each stage,
              as described below.

Each element of the array per has the following data.

  spe    - Rotational speed for the respective stage.
           (This is only used for variable speed coils to interpolate for 
           intermediate speeds).
  nomVal - Nominal performance values for the respective stage. Data of the
           nomVal record are:
Q_flow_nominal - Total rate of heat transfer at nominal conditions. COP_nominal - Coefficient of performance at nominal conditions. m_flow_nominal - Evaporator air mass flow rate at nominal conditions. TEvaIn_nominal - Evaporator air inlet wet-bulb temperature at nominal conditions. TConIn_nominal - Condenser air inlet temperature at nominal conditions (for evaporative coils, use wet bulb, otherwise use dry bulb temperature). phiIn_nominal - Relative humidity at evaporator inlet at nominal conditions. p_nominal - Atmospheric pressure at nominal conditions. per - Array of records with one performance curve for the respective stage of the coil. That is, the performance curves will be used in conjunction with the nominal values defined in the record spe:
capFunT - Coefficients of biquadratic polynomial for heating capacity as a function of temperature. capFunFF - Polynomial coefficients for heating capacity as a function of the mass flow fraction. EIRFunT - Coefficients of biquadratic polynomial for EIR as a function of temperature. EIRFunFF - Polynomial coefficients for EIR as a function of the mass flow fraction. TConInRan - Minimum and maximum condenser air inlet temperatures for which the performance curves are valid. Outside this range, they will be linearly extrapolated. TEvaInRan - Minimum and maximum evaporator air inlet temperatures for which the performance curves are valid. Outside this range, they will be linearly extrapolated. ffRan - Minimum and maximum air mass flow fraction (relative to m_flow_nominal) for which the performance curves are valid. Outside this range, they will be linearly extrapolated.

There can be an arbitrary number of polynomial coefficients for the record capFunFF and EIRFunFF. However, if a coil has multiple stages, then each stage must declare the same amount of polynomial coefficients. For example, if a quadratic function is used for stage one, then stage two must also use a quadratic function.

It also contains settings and performance curves for defrost operation and overall performance modifiers:

  defEIRFunT  - Coefficients of biquadratic polynomial for EIR for defrost as a 
                function of temperature.
  PLFraFunPLR - Coefficients of polynomial for part-load fraction as a function
                of part-load ratio.
  defOpe      - Defrost operation type.
  QDefResCap  - Capacity of heating element on outdoor coil (used for resistive defrost).  
  QCraCap     - Capacity of crankcase heater.
  defTri      - Defrost time fraction calculation method.
  tDefRun     - Fraction of time for which defrost is run if timed fraction calculation is used.
  TDefLim     - Maximum temperature at which the defrost operation may be run.

Extends from Modelica.Icons.Record (Icon for records).

Parameters

TypeNameDefaultDescription
IntegernSta Number of stages
RealminSpeRat0.2Minimum speed ratio
Stagesta[nSta]redeclare parameter Building...Data record for coil performance at each stage
DefrostOperationdefOpeBuildings.Fluid.DXSystems.He...Defrost operation type
DefrostTimeMethodsdefTriBuildings.Fluid.DXSystems.He...Type of method used to calculate defrost time fraction
RealtDefRun0.166Time period fraction for which defrost cycle is run [1]
ThermodynamicTemperatureTDefLim273.65Maximum temperature at which defrost operation is activated [K]
HeatFlowRateQDefResCap Heating capacity of resistive defrost element [W]
HeatFlowRateQCraCap Crankcase heater capacity [W]
RealdefEIRFunT[6]fill(0, 6)Biquadratic coefficients for defrost capacity function of temperature
RealPLFraFunPLR[:]{1}Quadratic/cubic equation for part load fraction as a function of part-load ratio
Minimum conditions
MassFlowRatem_flow_small0.0001*sta[nSta].nomVal.m_fl...Small mass flow rate for regularization near zero flow [kg/s]

Modelica definition

record DXCoil "Performance record for a DX Heating DXCoil with one or multiple stages" extends Modelica.Icons.Record; final parameter Boolean sinStaOpe = nSta == 1 "The data record is used for single speed operation"; parameter Integer nSta( final min=1) "Number of stages"; parameter Real minSpeRat( final min=0, final max=1)=0.2 "Minimum speed ratio"; replaceable parameter Buildings.Fluid.DXSystems.Heating.AirSource.Data.Generic.BaseClasses.Stage sta[nSta] "Data record for coil performance at each stage"; parameter Modelica.Units.SI.MassFlowRate m_flow_small=0.0001*sta[nSta].nomVal.m_flow_nominal "Small mass flow rate for regularization near zero flow"; parameter Buildings.Fluid.DXSystems.Heating.BaseClasses.Types.DefrostOperation defOpe=Buildings.Fluid.DXSystems.Heating.BaseClasses.Types.DefrostOperation.resistive "Defrost operation type"; parameter Buildings.Fluid.DXSystems.Heating.BaseClasses.Types.DefrostTimeMethods defTri=Buildings.Fluid.DXSystems.Heating.BaseClasses.Types.DefrostTimeMethods.timed "Type of method used to calculate defrost time fraction"; parameter Real tDefRun( final unit="1", displayUnit="1")=0.166 "Time period fraction for which defrost cycle is run"; parameter Modelica.Units.SI.ThermodynamicTemperature TDefLim=273.65 "Maximum temperature at which defrost operation is activated"; parameter Modelica.Units.SI.HeatFlowRate QDefResCap(min=0) "Heating capacity of resistive defrost element"; parameter Modelica.Units.SI.HeatFlowRate QCraCap(min=0) "Crankcase heater capacity"; //-----------------------------Performance curves-----------------------------// parameter Real defEIRFunT[6] = fill(0,6) "Biquadratic coefficients for defrost capacity function of temperature"; parameter Real PLFraFunPLR[:] = {1} "Quadratic/cubic equation for part load fraction as a function of part-load ratio"; end DXCoil;