modelPartialDXCoil

Partial model for air or water cooled DX cooling coil

Extends from Buildings.Fluid.DXSystems.Cooling.BaseClasses.EssentialParameters (A partial block for essential parameters for cooling DX coils), Buildings.Fluid.Interfaces.TwoPortHeatMassExchanger (Partial model transporting one fluid stream with storing mass or energy).

Information

This partial model is the base class for Buildings.Fluid.DXSystems.Cooling.BaseClasses.PartialDXCoolingCoil.

Parameters

Type	Name	Default	Description
Buildings.Fluid.DXSystems.Cooling.AirSource.Data.Generic.DXCoil	datCoi (from EssentialParameters)		Performance data
Boolean	homotopyInitialization (from TwoPortHeatMassExchanger)	true	= true, use homotopy method
Boolean	use_mCon_flow		Set to true to enable connector for the condenser mass flow rate
Assumptions
Boolean	allowFlowReversal (from PartialTwoPort)	true	= false to simplify equations, assuming, but not enforcing, no flow reversal
Nominal condition
Modelica.Units.SI.MassFlowRate	m_flow_nominal (from PartialTwoPortInterface)		Nominal mass flow rate
Modelica.Units.SI.PressureDifference	dp_nominal (from TwoPortFlowResistanceParameters)		Pressure difference
Advanced
Modelica.Units.SI.MassFlowRate	m_flow_small (from PartialTwoPortInterface)	1E-4*abs(m_flow_nominal)	Small mass flow rate for regularization of zero flow
Advanced › Diagnostics
Boolean	show_T (from PartialTwoPortInterface)	false	= true, if actual temperature at port is computed
Flow resistance
Boolean	computeFlowResistance (from TwoPortFlowResistanceParameters)	true	=true, compute flow resistance. Set to false to assume no friction
Boolean	from_dp (from TwoPortFlowResistanceParameters)	false	= true, use m_flow = f(dp) else dp = f(m_flow)
Real	n (from TwoPortFlowResistanceParameters)	2	Flow exponent, n=1 for laminar, n=2 for turbulent
Boolean	linearizeFlowResistance (from TwoPortFlowResistanceParameters)	false	= true, use linear relation between m_flow and dp for any flow rate
Real	deltaM (from TwoPortFlowResistanceParameters)	0.1	Fraction of nominal flow rate where flow transitions to laminar
Dynamics › Nominal condition
Modelica.Units.SI.Time	tau (from TwoPortHeatMassExchanger)	30	Time constant at nominal flow (if energyDynamics <> SteadyState)
Dynamics › Conservation equations
Modelica.Fluid.Types.Dynamics	energyDynamics (from TwoPortHeatMassExchanger)	Modelica.Fluid.Types.Dynamics.DynamicFreeInitial	Type of energy balance: dynamic (3 initialization options) or steady state
Initialization
Medium.AbsolutePressure	p_start (from TwoPortHeatMassExchanger)	Medium.p_default	Start value of pressure
Medium.Temperature	T_start (from TwoPortHeatMassExchanger)	Medium.T_default	Start value of temperature
Medium.MassFraction[Medium.nX]	X_start (from TwoPortHeatMassExchanger)	Medium.X_default	Start value of mass fractions m_i/m
Medium.ExtraProperty[Medium.nC]	C_start (from TwoPortHeatMassExchanger)	fill(0, Medium.nC)	Start value of trace substances
Dynamics › Moisture balance
Boolean	computeReevaporation	true	Set to true to compute reevaporation of water that accumulated on coil

Connectors

Type	Name	Description
Modelica.Fluid.Interfaces.FluidPort_a	port_a (from PartialTwoPort)	Fluid connector a (positive design flow direction is from port_a to port_b)
Modelica.Fluid.Interfaces.FluidPort_b	port_b (from PartialTwoPort)	Fluid connector b (positive design flow direction is from port_a to port_b)
Modelica.Blocks.Interfaces.RealInput	TOut	Outside air dry bulb temperature for an air cooled condenser or wetbulb temperature for an evaporative cooled condenser
Modelica.Blocks.Interfaces.RealInput	mCon_flow	Water mass flow rate for condenser
Modelica.Blocks.Interfaces.RealOutput	P	Electrical power consumed by the unit
Modelica.Blocks.Interfaces.RealOutput	QSen_flow	Sensible heat flow rate

Components

Type	Name	Default	Description
Modelica.Units.SI.MassFlowRate	m_flow (from PartialTwoPortInterface)	port_a.m_flow	Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction)
Modelica.Units.SI.PressureDifference	dp (from PartialTwoPortInterface)	port_a.p - port_b.p	Pressure difference between port_a and port_b
Medium.ThermodynamicState	sta_a (from PartialTwoPortInterface)	if allowFlowReversal then Medium.setState_phX(port_a.p, noEvent(actualStream(port_a.h_outflow)), noEvent(actualStream(port_a.Xi_outflow))) else Medium.setState_phX(port_a.p, noEvent(inStream(port_a.h_outflow)), noEvent(inStream(port_a.Xi_outflow)))	Medium properties in port_a
Medium.ThermodynamicState	sta_b (from PartialTwoPortInterface)	if allowFlowReversal then Medium.setState_phX(port_b.p, noEvent(actualStream(port_b.h_outflow)), noEvent(actualStream(port_b.Xi_outflow))) else Medium.setState_phX(port_b.p, noEvent(port_b.h_outflow), noEvent(port_b.Xi_outflow))	Medium properties in port_b
Buildings.Fluid.MixingVolumes.MixingVolume	vol (from TwoPortHeatMassExchanger)
Buildings.Fluid.FixedResistances.PressureDrop	preDro (from TwoPortHeatMassExchanger)		Flow resistance
Buildings.Fluid.DXSystems.Cooling.BaseClasses.PartialCoilInterface	dxCoi

Revisions

March 19, 2023, by Xing Lu and Karthik Devaprasad:
Changed baseclass to create common version for both heating and cooling coils.
Renamed TConIn to TOut.
Moved instances QLat_flow and eva to Buildings.Fluid.DXSystems.Cooling.BaseClasses.PartialDXCoolingCoil.
June 19, 2017, by Michael Wetter:
Added missing replaceable to the medium declaration.
This is for issue Buildings #810.
April 12, 2017, by Michael Wetter:
Removed temperature connection that is no longer needed.
This is for issue Buildings #704.
February 27, 2017 by Yangyang Fu:
Added redeclare for the type of cooCap in dxCoiOpe.
May 6, 2015 by Michael Wetter:
Added prescribedHeatFlowRate=true for vol.
August 31, 2013, by Michael Wetter:
Updated model due to change in Buildings.Fluid.BaseClasses.IndexMassFraction.
September 24, 2012 by Michael Wetter:
Revised documentation.
September 4, 2012 by Michael Wetter:
Moved assignments to declaration section to avoid mixing graphical modeling with textual modeling in equation section. Redeclare medium model as Modelica.Media.Interfaces.PartialCondensingGases to remove errors during model check. Added output connectors for sensible and latent heat flow rate.
April 12, 2012 by Kaustubh Phalak:
First implementation.