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 |
---|---|
DXCoil | Performance record for a DX Heating DXCoil with one or multiple stages |
BaseClasses | Package with base classes for performance data |
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 recordspe
:
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. [TConInMin, TConInMax] - Minimum and maximum condenser air inlet temperatures for which the performance curves are valid. Outside this range, they will be linearly extrapolated. [TEvaInMin, TEvaInMax] - Minimum and maximum evaporator air inlet temperatures for which the performance curves are valid. Outside this range, they will be linearly extrapolated. [ffMin, ffMax] - 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
Type | Name | Default | Description |
---|---|---|---|
Integer | nSta | Number of stages | |
Real | minSpeRat | 0.2 | Minimum speed ratio |
Stage | sta[nSta] | redeclare parameter Building... | Data record for coil performance at each stage |
DefrostOperation | defOpe | Buildings.Fluid.DXSystems.He... | Defrost operation type |
DefrostTimeMethods | defTri | Buildings.Fluid.DXSystems.He... | Type of method used to calculate defrost time fraction |
Real | tDefRun | 0.166 | Time period fraction for which defrost cycle is run [1] |
ThermodynamicTemperature | TDefLim | 273.65 | Maximum temperature at which defrost operation is activated [K] |
HeatFlowRate | QDefResCap | Heating capacity of resistive defrost element [W] | |
HeatFlowRate | QCraCap | Crankcase heater capacity [W] | |
Real | defEIRFunT[6] | fill(0, 6) | Biquadratic coefficients for defrost capacity as a function of temperature |
Real | PLFraFunPLR[:] | {1} | Quadratic/cubic equation for part load fraction as a function of part-load ratio |
Minimum conditions | |||
MassFlowRate | m_flow_small | 0.0001*sta[nSta].nomVal.m_fl... | Small mass flow rate for regularization near zero flow [kg/s] |