AIRFLOWNETWORK:SIMULATIONCONTROL

This object defines the global parameters used in an Airflow Network simulation.

Name

Enter a unique name for this object.

AirflowNetwork Control

Type: choice (MultizoneWithDistribution, MultizoneWithoutDistribution, MultizoneWithDistributionOnlyDuringFanOperation or NoMultizoneOrDistribution)
NoMultizoneOrDistribution: Only perform Simple calculations (objects ZoneInfiltration:*, ZoneVentilation:*, ZoneMixing, ZoneCrossMixing, ZoneRefrigerationDoorMixing, ZoneAirBalance:OutdoorAir, ZoneEarthtube, ZoneThermalChimney, and ZoneCoolTower:Shower); MultizoneWithoutDistribution: Use AirflowNetwork objects to simulate multizone Airflows driven by wind during simulation time, and objects of ZoneInfiltration:*, ZoneVentilation:*, ZoneMixing, ZoneCrossMixing ZoneRefrigerationDoorMixing, ZoneAirBalance:OutdoorAir, ZoneEarthtube, ZoneThermalChimney, and ZoneCoolTower:Shower are ignored; MultizoneWithDistributionOnlyDuringFanOperation: Perform distribution system calculations during system fan on time and Simple calculations during system Fan off time; MultizoneWithDistribution: Perform distribution system calculations during system fan on time and multizone Airflow driven by wind during system fan off time.
Default: NoMultizoneOrDistribution

Wind Pressure Coefficient Type

Type: choice (Input or SurfaceAverageCalculation)
Input: User must enter AirflowNetwork:MultiZone:WindPressureCoefficientArray, AirflowNetwork:MultiZone:ExternalNode, and AirflowNetwork:MultiZone:WindPressureCoefficientValues objects. SurfaceAverageCalculation: used only for rectangular buildings. If SurfaceAverageCalculation is selected, AirflowNetwork:MultiZone:WindPressureCoefficientArray, AirflowNetwork:MultiZone:ExternalNode, and AirflowNetwork:MultiZone:WindPressureCoefficientValues objects are not used.
Default: SurfaceAverageCalculation

Height Selection for Local Wind Pressure Calculation

Type: choice (ExternalNode or OpeningHeight)
If ExternalNode is selected, the height given in the AirflowNetwork:MultiZone:ExternalNode object will be used. If OpeningHeight is selected, the surface opening height (centroid) will be used to calculate local wind pressure This field is ignored when the choice of the Wind Pressure Coefficient Type field is SurfaceAverageCalculation.
Default: OpeningHeight

Building Type

Type: choice (LowRise or HighRise)
Used only if Wind Pressure Coefficient Type = SurfaceAverageCalculation, otherwise this field may be left blank.
Default: LowRise

Maximum Number of Iterations

Type: integer
Determines the maximum number of iterations used to converge on a solution. If this limit is exceeded, the program terminates.
Unit: dimensionless
Maximum: 30000
Default: 500

Initialization Type

Type: choice (LinearInitializationMethod or ZeroNodePressures)
Default: ZeroNodePressures

Relative Airflow Convergence Tolerance

Type: real number
This tolerance is defined as the absolute value of the sum of the mass Flow Rates divided by the sum of the absolute value of the mass Flow Rates. The mass Flow Rates described here refer to the mass Flow Rates at all Nodes in the AirflowNetwork model. The solution converges when both this tolerance and the tolerance in the next field (Absolute Airflow Convergence Tolerance) are satisfied.
Unit: dimensionless
Default: 1.E-4

Absolute Airflow Convergence Tolerance

Type: real number
This tolerance is defined as the absolute value of the sum of the mass flow rates. The mass flow rates described here refer to the mass flow rates at all nodes in the AirflowNetwork model. The solution converges when both this tolerance and the tolerance in the previous field (Relative Airflow Convergence Tolerance) are satisfied.
Unit: kg/s
Default: 1.E-6

Convergence Acceleration Limit

Type: real number
Used only for AirflowNetwork:SimulationControl
Unit: dimensionless
Minimum: -1
Maximum: 1
Default: -0.5

Azimuth Angle of Long Axis of Building

Type: real number
Degrees clockwise from true North. Used only if Wind Pressure Coefficient Type = SurfaceAverageCalculation.
Unit: deg
Minimum: 0.0
Maximum: 180.0
Default: 0.0

Ratio of Building Width Along Short Axis to Width Along Long Axis

Type: real number
Used only if Wind Pressure Coefficient Type = SurfaceAverageCalculation.
Maximum: 1.0
Default: 1.0

Height Dependence of External Node Temperature

Type: choice (Yes or No)
If Yes, external node temperature is height dependent. If No, external node temperature is based on zero height.
Default: No

Solver

Type: choice (SkylineLU or ConjugateGradient)
Select the solver to use for the pressure network solution
Default: SkylineLU