I'm modeling a very simple house with a single thermal zone with CAV DX coil cooling with a single air duct. In order to test cooling loads reduction with window opening, I constructed a simple AFN for natural ventilation, using NoMultizoneOr Distribution and Surface Average Calculation method (I am a novice to Airflownetwork (AFN) though).
However, even though the AFN is set, I find no change in cooling loads. Can anyone explain why? and how to fix this problem? Thanks in advance. My inputs are as follows:
!- =========== ALL OBJECTS IN CLASS: AIRFLOWNETWORK:SIMULATIONCONTROL ===========
AirflowNetwork:SimulationControl,
EllisAirNetwork, !- Name
NoMultizoneOrDistribution, !- AirflowNetwork Control
SurfaceAverageCalculation, !- Wind Pressure Coefficient Type
, !- AirflowNetwork Wind Pressure Coefficient Array Name
, !- Height Selection for Local Wind Speed Calculation
LowRise, !- Building Type
500, !- Maximum Number of Iterations {dimensionless}
LinearInitializationMethod, !- Initialization Type
0.0001, !- Relative Airflow Convergence Tolerance {dimensionless}
0.000001, !- Absolute Airflow Convergence Tolerance {kg/s}
-.5, !- Convergence Acceleration Limit {dimensionless}
90, !- Azimuth Angle of Long Axis of Building {deg}
0.95; !- Ratio of Building Width Along Short Axis to Width Along Long Axis
!- =========== ALL OBJECTS IN CLASS: AIRFLOWNETWORK:MULTIZONE:ZONE ===========
AirflowNetwork:MultiZone:Zone,
Thermal Zone 1, !- Zone Name
Constant, !- Ventilation Control Mode
Ellis House ClgSetp 1, !- Ventilation Control Zone Temperature Setpoint Schedule Name
0.5, !- Minimum Venting Open Factor {dimensionless}
3, !- Indoor and Outdoor Temperature Difference Lower Limit For Maximum Venting Open Factor {deltaC}
10, !- Indoor and Outdoor Temperature Difference Upper Limit for Minimun Venting Open Factor {deltaC}
0.0, !- Indoor and Outdoor Enthalpy Difference Lower Limit For Maximum Venting Open Factor {deltaJ/kg}
300000.0; !- Indoor and Outdoor Enthalpy Difference Upper Limit for Minimun Venting Open Factor {deltaJ/kg}
!- =========== ALL OBJECTS IN CLASS: AIRFLOWNETWORK:MULTIZONE:SURFACE ===========
AirflowNetwork:MultiZone:Surface,
Sub Surface 1, !- Surface Name
VentOpening, !- Leakage Component Name
Sfacade, !- External Node Name
0.6, !- Window/Door Opening Factor, or Crack Factor {dimensionless}
Constant, !- Ventilation Control Mode
, !- Ventilation Control Zone Temperature Setpoint Schedule Name
0.1, !- Minimum Venting Open Factor {dimensionless}
2, !- Indoor and Outdoor Temperature Difference Lower Limit For Maximum Venting Open Factor {deltaC}
3, !- Indoor and Outdoor Temperature Difference Upper Limit for Minimun Venting Open Factor {deltaC}
, !- Indoor and Outdoor Enthalpy Difference Lower Limit For Maximum Venting Open Factor {deltaJ/kg}
300000, !- Indoor and Outdoor Enthalpy Difference Upper Limit for Minimun Venting Open Factor {deltaJ/kg}
Always On; !- Venting Availability Schedule Name
AirflowNetwork:MultiZone:Surface,
Sub Surface 4, !- Surface Name
VentOpening, !- Leakage Component Name
Nfacade, !- External Node Name
0.4, !- Window/Door Opening Factor, or Crack Factor {dimensionless}
Constant, !- Ventilation Control Mode
, !- Ventilation Control Zone Temperature Setpoint Schedule Name
0.1, !- Minimum Venting Open Factor {dimensionless}
1, !- Indoor and Outdoor Temperature Difference Lower Limit For Maximum Venting Open Factor {deltaC}
3, !- Indoor and Outdoor Temperature Difference Upper Limit for Minimun Venting Open Factor {deltaC}
, !- Indoor and Outdoor Enthalpy Difference Lower Limit For Maximum Venting Open Factor {deltaJ/kg}
300000, !- Indoor and Outdoor Enthalpy Difference Upper Limit for Minimun Venting Open Factor {deltaJ/kg}
Always On; !- Venting Availability Schedule Name
!- =========== ALL OBJECTS IN CLASS: AIRFLOWNETWORK:MULTIZONE:COMPONENT:SIMPLEOPENING ===========
AirflowNetwork:MultiZone:Component:SimpleOpening,
VentOpening, !- Name
0.001, !- Air Mass Flow Coefficient When Opening is Closed {kg/s-m}
0.65, !- Air Mass Flow Exponent When Opening is Closed {dimensionless}
0.0001, !- Minimum Density Difference for Two-Way Flow {kg/m3}
1; !- Discharge Coefficient {dimensionless}
!- =========== ALL OBJECTS IN CLASS: AIRFLOWNETWORK:MULTIZONE:EXTERNALNODE ===========
AirflowNetwork:MultiZone:ExternalNode,
Sfacade, !- Name
6, !- External Node Height {m}
W; !- Wind Pressure Coefficient Values Object Name
AirflowNetwork:MultiZone:ExternalNode,
Nfacade, !- Name
6, !- External Node Height {m}
W; !- Wind Pressure Coefficient Values Object Name
!- =========== ALL OBJECTS IN CLASS: DESIGNSPECIFICATION:OUTDOORAIR ===========
DesignSpecification:OutdoorAir,
Outdoor Air, !- Name
Sum, !- Outdoor Air Method
0, !- Outdoor Air Flow per Person {m3/s-person}
0, !- Outdoor Air Flow per Zone Floor Area {m3/s-m2}
0, !- Outdoor Air Flow per Zone {m3/s}
0; !- Outdoor Air Flow Air Changes per Hour {1/hr}
