modelEmpirical

Empirical air filter model

Extends from Buildings.Fluid.Interfaces.PartialTwoPort (Partial component with two ports).

Information

Component that empirically models the performance of air filters, focusing on key factors such as contamination and pressure drop, without requiring geometric data.

The model uses as parameters performance characteristics that describe how the filter works under various conditions. The performance of the air filter is characterized by a performance dataset per (see Buildings.Fluid.AirFilters.Data.Generic), which contains key parameters that define the filter:

Contaminant Names: The array per.namCon defines the type of contaminants that can be captured by the filter.
Nominal Conditions: They include the nominal pressure drop dp_nominal and the nominal mass flow rate m_flow_nominal of the clean filter. They also include the maximum total mass of contaminants mCon_max that the filter can hold.
Resistance Coefficient: The parameter per.b describes how the pressure drop of the filter increases as the contaminants accumulate over time. See Buildings.Fluid.AirFilters.BaseClasses.FlowCoefficientCorrection for more information.
Filtration Efficiency Curves: The array per.filEffPar contains the filtration efficiency curves. Each curve defines the efficiencies for capturing each contaminant that is defined in per.namCon. See Buildings.Fluid.AirFilters.BaseClasses.FiltrationEfficiency for more information.

The input boolean flag, uRep, indicates that the filter has been replaced and thus reset the mass accumulation to the initial status, i.e., when uRep changes from false to true, the mass of the captured contaminants is reset to per.mCon_start.

Note:

Warnings will be written when,

the captured contaminant mass exceeds the mCon_max, or
the extraPropertiesNames in the medium model does not contain all the contaminants specified in the per.namCon.

References

Parameters

Type	Name	Default	Description
Buildings.Fluid.AirFilters.Data.Generic	per		Performance dataset
Assumptions
Boolean	allowFlowReversal (from PartialTwoPort)	true	= false to simplify equations, assuming, but not enforcing, no flow reversal

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)
Buildings.Controls.OBC.CDL.Interfaces.BooleanInput	uRep	True: replace the filter and reset the accumulation
Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput	yRep	True if the filter is full and should be replaced
Buildings.Controls.OBC.CDL.Interfaces.RealOutput	rat	Relative mass of the contaminant captured by the filter, which is the total captured contaminant mass divided by the filter's maximum contaminant capacity
Buildings.Controls.OBC.CDL.Interfaces.RealOutput[nConSub]	eps	Filtration efficiency

Components

Type	Name	Default	Description
Buildings.Fluid.AirFilters.BaseClasses.MassAccumulation	masAcc		Contaminant accumulation

Revisions

December 22, 2023, by Sen Huang:
First implementation.