Orphan Controller:MechanicalVentilation object

[DavidGoldwasser]

I made a three loop model with 6 thermal zones. Loops A and B are single zone loops. Initially I hooked Zone 1 up to loop A, Zone 2 up to Loop B, and Zones 3-6 up to loop C.

I then disconnected Zone 3 from Loop C, disconnected Zone 1 from Loop A, and then connected Zone 3 to Loop A.

When I ran I got this error. Below are the three Controller:MechanicalVentilation objects.

** Severe ** IP: IDF line~7822 Object=CONTROLLER:MECHANICALVENTILATION, name=CONTROLLER MECHANICAL VENTILATION 1, Required Field=[Zone 1 Name] was blank.

@kbenne cc: @asparke2 I'll email the OSM file. This was from a clean file i made today with the 1.1.0 installer.

Controller:MechanicalVentilation,
Controller Mechanical Ventilation 1, !- Name
Always On Discrete, !- Availability Schedule Name
No, !- Demand Controlled Ventilation
ZoneSum, !- System Outdoor Air Method
; !- Zone Maximum Outdoor Air Fraction {dimensionless}

Controller:MechanicalVentilation,
Controller Mechanical Ventilation 3, !- Name
Always On Discrete, !- Availability Schedule Name
No, !- Demand Controlled Ventilation
ZoneSum, !- System Outdoor Air Method
, !- Zone Maximum Outdoor Air Fraction {dimensionless}
Thermal Zone 1, !- Zone Name 1
LargeHotel Banquet Outdoor Air, !- Design Specification Outdoor Air Object Name 1
Thermal Zone 1 Design Spec Zone Air Dist, !- Design Specification Zone Air Distribution Object Name 1
Thermal Zone 4, !- Zone Name 2
LargeHotel Cafe Outdoor Air, !- Design Specification Outdoor Air Object Name 2
Thermal Zone 4 Design Spec Zone Air Dist, !- Design Specification Zone Air Distribution Object Name 2
Thermal Zone 5, !- Zone Name 3
LargeHotel GuestRoom Outdoor Air, !- Design Specification Outdoor Air Object Name 3
Thermal Zone 5 Design Spec Zone Air Dist, !- Design Specification Zone Air Distribution Object Name 3
Thermal Zone 6, !- Zone Name 4
LargeHotel Corridor Outdoor Air, !- Design Specification Outdoor Air Object Name 4
Thermal Zone 6 Design Spec Zone Air Dist; !- Design Specification Zone Air Distribution Object Name 4

Controller:MechanicalVentilation,
Controller Mechanical Ventilation 2, !- Name
Always On Discrete, !- Availability Schedule Name
No, !- Demand Controlled Ventilation
ZoneSum, !- System Outdoor Air Method
, !- Zone Maximum Outdoor Air Fraction {dimensionless}
Thermal Zone 2, !- Zone Name 1
LargeHotel Laundry Outdoor Air, !- Design Specification Outdoor Air Object Name 1
Thermal Zone 2 Design Spec Zone Air Dist; !- Design Specification Zone Air Distribution Object Name 1

[kbenne]

Sure sounds like the old problem. Missing design days or missing ventilation.

---

From: DavidGoldwasser [notifications@github.com]
Sent: Monday, November 11, 2013 2:12 PM
To: NREL/OpenStudio
Cc: Benne, Kyle
Subject: [OpenStudio] Orphan Controller:MechanicalVentilation object (#641)

I made a three loop model with 6 thermal zones. Loops A and B are single zone loops. Initially I hooked Zone 1 up to loop A, Zone 2 up to Loop B, and Zones 3-6 up to loop C.

I then disconnected Zone 3 from Loop C, disconnected Zone 1 from Loop A, and then connected Zone 3 to Loop A.

When I ran I got this error. Below are the three Controller:MechanicalVentilation objects.

** Severe ** IP: IDF line~7822 Object=CONTROLLER:MECHANICALVENTILATION, name=CONTROLLER MECHANICAL VENTILATION 1, Required Field=[Zone 1 Name] was blank.

@kbennehttps://github.com/kbenne cc: @asparke2https://github.com/asparke2 I'll email the OSM file. This was from a clean file i made today with the 1.1.0 installer.

Controller:MechanicalVentilation,
Controller Mechanical Ventilation 1, !- Name
Always On Discrete, !- Availability Schedule Name
No, !- Demand Controlled Ventilation
ZoneSum, !- System Outdoor Air Method
; !- Zone Maximum Outdoor Air Fraction {dimensionless}

Controller:MechanicalVentilation,
Controller Mechanical Ventilation 3, !- Name
Always On Discrete, !- Availability Schedule Name
No, !- Demand Controlled Ventilation
ZoneSum, !- System Outdoor Air Method
, !- Zone Maximum Outdoor Air Fraction {dimensionless}
Thermal Zone 1, !- Zone Name 1
LargeHotel Banquet Outdoor Air, !- Design Specification Outdoor Air Object Name 1
Thermal Zone 1 Design Spec Zone Air Dist, !- Design Specification Zone Air Distribution Object Name 1
Thermal Zone 4, !- Zone Name 2
LargeHotel Cafe Outdoor Air, !- Design Specification Outdoor Air Object Name 2
Thermal Zone 4 Design Spec Zone Air Dist, !- Design Specification Zone Air Distribution Object Name 2
Thermal Zone 5, !- Zone Name 3
LargeHotel GuestRoom Outdoor Air, !- Design Specification Outdoor Air Object Name 3
Thermal Zone 5 Design Spec Zone Air Dist, !- Design Specification Zone Air Distribution Object Name 3
Thermal Zone 6, !- Zone Name 4
LargeHotel Corridor Outdoor Air, !- Design Specification Outdoor Air Object Name 4
Thermal Zone 6 Design Spec Zone Air Dist; !- Design Specification Zone Air Distribution Object Name 4

Controller:MechanicalVentilation,
Controller Mechanical Ventilation 2, !- Name
Always On Discrete, !- Availability Schedule Name
No, !- Demand Controlled Ventilation
ZoneSum, !- System Outdoor Air Method
, !- Zone Maximum Outdoor Air Fraction {dimensionless}
Thermal Zone 2, !- Zone Name 1
LargeHotel Laundry Outdoor Air, !- Design Specification Outdoor Air Object Name 1
Thermal Zone 2 Design Spec Zone Air Dist; !- Design Specification Zone Air Distribution Object Name 1

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/641.

[DavidGoldwasser]

@kbenne that isn't the issue.

FYI - deleting and re-adding the outdoor air object and thermal zone didn't clean up the file, but throwing away the air loop and adding it back worked.

[kbenne]

@DavidGoldwasser Do we know the steps to make this happen? Perhaps there is a strange dependence on the order of operations. Like adding OA system before there are ventilation requirements. Looking at the code I can't explain something like that, but it might still be there.

[kbenne]

@DavidGoldwasser sorry David I should have reread. I think your description is very good. :)

[kbenne]

@DavidGoldwasser

"I then disconnected Zone 3 from Loop C, disconnected Zone 1 from Loop A, and then connected Zone 3 to Loop A."

So was Zone 1 left without a system?

[kbenne]

@DavidGoldwasser can you send the file again or put it in the openstudio-files repo?

[kbenne]

@DavidGoldwasser don't bother I followed your exact steps and was able to reproduce this. Weird. I'm a little surprised this has managed to lurk so long. Stay tuned for a fix.

[kbenne]

@DavidGoldwasser Oh. I think I know what it is. When you remove all zones from an AirLoopHVAC system, the terminal is also removed. Attached zones with no equipment (the terminal counts as equipment) do not get added to the mechanical ventilation controller.

You might want the terminal to hang around after detaching the last zone, or you might prefer more explicit messaging of the root error, but lets file those as separate features. The behavior of removing the last zone has wavered, this works tried and true, so I'm inclined to leave it, but I would entertain a feature request for change in behavior.

Bottom line. check your model. I am almost certain you don't have a terminal on that Loop A.

[kbenne]

Going with this instead, which adds the untranslated objects, errors and warnings at @macumber's request.

[DavidGoldwasser]

Makes sense, users needs to add the terminal back on their own if they have added, and then deleted a zone from an air loop, and then want to add a new one back.