Why the AvailabilityManager:NightVentilation can not change the fan operation mode

asked 2020-11-26 14:24:51 -0500

feilongdang gravatar image

updated 2021-03-29 08:58:11 -0500

I want to use ZonePackaged: HeatPump to supply the conditioned air in the daytime and induce the outdoor air at night. I followed the "5ZoneNightVent3" to use the availability manager and set the Fan:SystemModel.

After the simulation, the AvailabilityManager:NightVentilation works, so that the fan can work at night to supply outdoor air. When I can change the ventilation temperature difference, the low limit temperature in the AvailabilityManager:NightVentilation, they work properly.

But the problems are: (1) The fan's power at night is the same as the power at daytime, which means the 67 pa (Night Ventilation Mode Pressure Rise) set in Fan:SystemModel does not work; (2) the night venting flow fraction set in AvailabilityManager:NightVentilation does not work, which I cannot change the desired airflow rate at night. I have to say I also changed the two parameters mentioned above in the E+ example, they work properly. But I am stuck in my own case. Could anyone knows how to solve this problem? Thank you all.


NV Avail,                !- Name
NightVentSched,          !- Applicability Schedule Name
FanAvailSched,           !- Fan Schedule Name
VentTempSched,           !- Ventilation Temperature Schedule Name
3,                       !- Ventilation Temperature Difference {deltaC}
18,                      !- Ventilation Temperature Low Limit {C}
2,                       !- Night Venting Flow Fraction
Room;                    !- Control Zone Name


Room PTHP Supply Fan,    !- Name
FanAvailSched,           !- Availability Schedule Name
Room PTHP Heating Coil Outlet,  !- Air Inlet Node Name
Room PTHP Supply Fan Outlet,  !- Air Outlet Node Name
autosize,                !- Design Maximum Air Flow Rate {m3/s}
Continuous,              !- Speed Control Method
0.2,                     !- Electric Power Minimum Flow Rate Fraction
600,                     !- Design Pressure Rise {Pa}
0.9,                     !- Motor Efficiency
1,                       !- Motor In Air Stream Fraction
autosize,                !- Design Electric Power Consumption {W}
TotalEfficiencyAndPressure,  !- Design Power Sizing Method
,                        !- Electric Power Per Unit Flow Rate {W/(m3/s)}
,                        !- Electric Power Per Unit Flow Rate Per Unit Pressure {W/((m3/s)-Pa)}
0.7,                     !- Fan Total Efficiency
VAV Fan Curve,           !- Electric Power Function of Flow Fraction Curve Name
67,                      !- Night Ventilation Mode Pressure Rise {Pa}
,                        !- Night Ventilation Mode Flow Fraction
,                        !- Motor Loss Zone Name
,                        !- Motor Loss Radiative Fraction
General,                 !- End-Use Subcategory
1;                       !- Number of Speeds


Room PTHP,               !- Name
,                        !- Availability Schedule Name
Room PTHP Return,        !- Air Inlet Node Name
Room PTHP Supply Inlet,  !- Air Outlet Node Name
OutdoorAir:Mixer,        !- Outdoor Air Mixer Object Type
Room PTHP OA Mixing Box, !- Outdoor Air Mixer Name
autosize,                !- Cooling Supply Air Flow Rate {m3/s}
autosize,                !- Heating Supply Air Flow Rate {m3/s}
,                        !- No Load Supply Air Flow Rate {m3/s}
autosize,                !- Cooling Outdoor Air Flow Rate {m3/s}
autosize,                !- Heating Outdoor Air Flow Rate {m3/s}
autosize,                !- No Load Outdoor Air Flow Rate {m3/s}
Fan:SystemModel,         !- Supply Air Fan Object Type
Room PTHP Supply Fan,    !- Supply Air Fan Name
Coil:Heating:DX:SingleSpeed,  !- Heating Coil Object Type
Room PTHP Heating Coil,  !- Heating Coil Name
0.001,                   !- Heating Convergence Tolerance {dimensionless}
Coil:Cooling:DX:SingleSpeed,  !- Cooling Coil Object Type
Room PTHP Cooling Coil,  !- Cooling Coil Name
0.001,                   !- Cooling Convergence Tolerance {dimensionless}
Coil:Heating:Electric,   !- Supplemental Heating Coil Object ...
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