Hi all,
I'm trying to modulate, or to be precise, cancel the modulation of the opening size of an AirflowNetwork:Multizone:Surface object so that it can either be fully open (i.e. Multiplier equals 1.0) or closed i.e. (Multiplier equals 0.0) depending on the ventilation control mode. I have managed to achieve this when the ventilation control mode is set to 'Constant' by specifying a venting availabilty schedule. However, when using 'Temperature' as the ventilation control mode and by setting the Ventilation control zone temperature setpoint at 22 C I found that the output for the 'Window/Door opening factor' is greater than 0.0 even when the zone temperature is below 22 C, that is when Tzone < Tset indicating that the window is partially open. As shown below, I've tried to overcome this by setting the minimum venting opening factor field in the AirflowNetwork:Multizone:Zone object to 1.0. I've also set the two sets of Opening factor Data in the AirflowNetwork:Multizone:Component:DetailedOpening to have similar values in all fields (discharge coefficient, width factor, height factor and start height factor). However I still get the same results where there is no signifact difference in volume flow rates when Tzone is lower than or higher than Tset provided that Tzone > Tout.
Can anyone tell me why this is happening?
Thanks in advance,
Omar
AirflowNetwork:SimulationControl,
Simulation Control, !- Name
MultizoneWithoutDistribution, !- AirflowNetwork Control
Input, !- Wind Pressure Coefficient Type
All Angles, !- AirflowNetwork Wind Pressure Coefficient Array Name
ExternalNode, !- Height Selection for Local Wind Speed Calculation
, !- Building Type
500, !- Maximum Number of Iterations {dimensionless}
ZeroNodePressures, !- Initialization Type
0.0001, !- Relative Airflow Convergence Tolerance {dimensionless}
0.000001, !- Absolute Airflow Convergence Tolerance {kg/s}
-0.5, !- Convergence Acceleration Limit {dimensionless}
0, !- Azimuth Angle of Long Axis of Building {deg}
0.5; !- Ratio of Building Width Along Short Axis to Width Along Long Axis
AirflowNetwork:MultiZone:Zone,
1, !- Zone Name
Temperature, !- Ventilation Control Mode
NV Setpoint Schedule, !- Ventilation Control Zone Temperature Setpoint Schedule Name
1, !- Minimum Venting Open Factor {dimensionless}
0, !- Indoor and Outdoor Temperature Difference Lower Limit For Maximum Venting Open Factor {deltaC}
100, !- 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}
AirflowNetwork:MultiZone:Surface,
1-S WIN, !- Surface Name
Window 1, !- Leakage Component Name
South Node, !- External Node Name
1, !- Window/Door Opening Factor, or Crack Factor {dimensionless}
ZoneLevel, !- Ventilation Control Mode
, !- Ventilation Control Zone Temperature Setpoint Schedule Name
, !- Minimum Venting Open Factor {dimensionless}
, !- Indoor and Outdoor Temperature Difference Lower Limit For Maximum Venting Open Factor {deltaC}
100, !- 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}
AirflowNetwork:MultiZone:Surface,
1-N WIN, !- Surface Name
Window 1, !- Leakage Component Name
North Node, !- External Node Name
1, !- Window/Door Opening Factor, or Crack Factor {dimensionless}
ZoneLevel, !- Ventilation Control Mode
, !- Ventilation Control Zone Temperature Setpoint Schedule Name
, !- Minimum Venting Open Factor {dimensionless}
, !- Indoor and Outdoor Temperature Difference Lower Limit For Maximum Venting Open Factor {deltaC}
100, !- 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}
AirflowNetwork:MultiZone:Component:DetailedOpening,
Window 1, !- 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}
NonPivoted, !- Type of Rectanguler Large Vertical Opening (LVO)
0, !- Extra Crack Length or Height of Pivoting Axis {m}
2, !- Number of Sets of Opening Factor Data
0, !- Opening Factor 1 {dimensionless}
0.6, !- Discharge Coefficient for Opening Factor 1 {dimensionless}
1, !- Width Factor for Opening Factor 1 {dimensionless}
1, !- Height Factor for Opening Factor 1 {dimensionless}
0, !- Start Height Factor for Opening Factor 1 {dimensionless}
1, !- Opening Factor 2 {dimensionless}
0.6, !- Discharge Coefficient for Opening Factor 2 {dimensionless}
1, !- Width Factor for Opening Factor 2 {dimensionless}
1, !- Height Factor for Opening Factor 2 {dimensionless}
0; &nbs