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I can't get a Service Hot Water Plant Loop to Run.

asked 2016-02-17 14:20:13 -0600

Mark's avatar

updated 2016-02-17 21:13:39 -0600

Chandan Sharma's avatar

I have been working at this for 2 days, although admittedly am a rookie at using this program. I have setup a hot service loop but continue to get this error:

*************  16079 PlantEquipmentOperationSchemes,
   ************* indicated Name=Plant Loop 1 Operation Schemes
   ************* Only last 4 lines before error line shown.....
   *************  16080   Plant Loop 1 Operation Schemes,         !- Name
   *************  16081   PlantEquipmentOperation:HeatingLoad,    !- Control Scheme Object Type 1
   *************  16082   Plant Loop 1 Heating Operation Scheme,  !- Control Scheme Name 1
   *************  16083   ,                                       !- Control Scheme Schedule Name 1
   ** Severe  ** IP: IDF line~16083 Error detected in Object=PLANTEQUIPMENTOPERATIONSCHEMES, name=PLANT LOOP 1 OPERATION SCHEMES
   **   ~~~   ** Field [Control Scheme 1 Schedule Name] is required but was blank
   ** Warning ** IP: Note -- Some missing fields have been filled with defaults. See the audit output file for details.
   ** Severe  ** IP: Blank "required" fields found in input
   ** Severe  ** IP: Out of "range" values and/or blank required fields found in input
   **  Fatal  ** IP: Errors occurred on processing IDF file. Preceding condition(s) cause termination.

I have modeled the same loop in a simple single space/zone model and it works no problem.

Any help will be appreciated.


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answered 2016-02-19 09:57:27 -0600

I bet this is the same bug as this (closed) issue. I would suggest updating to OpenStudio 1.10.0 to see if this fixes your problem. If it does not then there is another potential bug.

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I am using 1.10.0. And it does sound the like the same type of issue. What is odd, is the same system will work in a simple model that I set up.

Mark's avatar Mark  ( 2016-02-19 10:12:55 -0600 )edit

answered 2016-02-19 23:14:25 -0600

Got the file from @Mark and took a look. The issue is that this model has a schedule named "Always On Discrete" that has a value of 0.33 instead of 1.

There are several other schedules named "Always On Discrete N" where N is an integer in this model. These schedules are all always on with a value of 1.

The OpenStudio Model has a method named Model::alwaysOnDiscrete that looks for a schedule matching the pattern of an always on discrete schedule. The exact pattern that OS is looking for is a schedule named "Always On Discrete" with value 1 and type limits of "Discrete". If found the method returns the existing schedule, if it is not found it creates a new one.

In this model since there is already a schedule named Always On Discrete but it does not fit the pattern of the always on schedule (because it has value 0.33), OS makes a new one. Since the name "Always On Discrete" is taken, OpenStudio appends a digit to make the new schedule's name unique. In fact every time that OS attempts to access the Model::alwaysOnDiscrete it creates a new schedule. Behind the scenes OS calls this method frequently so the model had accumulated several always on schedules.

When OS makes the plant operation schemes it expects an "Always On Discrete" schedule with value 1 to already be in the model AND idf. Because in this model each call to ::alwaysOnDiscrete ends up making a new schedule, that new schedule never gets translated into the idf. The translation process expects schedules to already be translated before plants are translated.

This is perhaps too much detail, but it might be helpful for some people to know that Model::alwaysOnDiscrete is a little special and that there is an OS API to create it. The bottom line is that this particular problem was caused by the schedule having an unexpected value of 0.33. OpenStudio should be robust enough to handle this, and I intend to make a couple of changes to make it more robust.

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@Mark I'm sending a repaired version of your model back via email.

Kyle Benne's avatar Kyle Benne  ( 2016-02-19 23:15:11 -0600 )edit

Thanks very much @Kyle Benne!

Mark's avatar Mark  ( 2016-02-20 21:22:27 -0600 )edit

answered 2016-02-17 21:13:16 -0600

Chandan Sharma's avatar

The error message is saying "!- Control Scheme Schedule Name 1" is missing at idf line 16083.

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Yes, I realize this, but how do I rectify it and how did it happen? The same system works on a different model.

Mark's avatar Mark  ( 2016-02-17 21:40:28 -0600 )edit

EnergyPlus plant example files can help in setting up the idf.

Chandan Sharma's avatar Chandan Sharma  ( 2016-02-17 22:52:14 -0600 )edit

I have entered the missing name in to the idf file. When I re-open Open Studio the new schedule is there. However, when I run the simulation, the schedule is lost again. I think there may be a bug with OS. Any suggestions?

Mark's avatar Mark  ( 2016-02-18 08:53:25 -0600 )edit

I have added the name in the EP idf editor and then run the simulation in EP and it runs through no problem. Must be an OS bug?

Mark's avatar Mark  ( 2016-02-18 16:47:55 -0600 )edit

Not aware of any such issue. Maybe @macumber or @David Goldwasser can shed some light.

Chandan Sharma's avatar Chandan Sharma  ( 2016-02-19 03:43:40 -0600 )edit

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Asked: 2016-02-17 14:20:13 -0600

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Last updated: Feb 19 '16