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# Error while trying to output Zone People Occupant Count from energyplus

Hi, i am trying to extract the information about the number of occupants in a zone from the energyPlus simulation via BCVTB, However the following error is found in the .err file:

** Severe  ** ExternalInterface: Simulation model has no variable "ZONE PEOPLE OCCUPANT COUNT" with key "WEST ZONE".
**  Fatal  ** Error in ExternalInterface: Check EnergyPlus *.err file.
...Summary of Errors that led to program termination:
..... Reference severe error count=1
..... Last severe error=ExternalInterface: Simulation model has no variable "ZONE PEOPLE OCCUPANT COUNT" with key "WEST ZONE".
************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 1 Severe Errors.
************* EnergyPlus Sizing Error Summary. During Sizing: 0 Warning; 0 Severe Errors.
************* EnergyPlus Terminated--Fatal Error Detected. 4 Warning; 1 Severe Errors; Elapsed Time=00hr 00min  0.90sec


I am using EnergyPlusV8-5-0 for the simulation of a building. Then using the bcvtb software i am trying to feed the number of occupants in a zone to a python program as input vai command line arguments.

The lines related to the Zone People Occupant Count in the .idf file is:

Output:Variable,*,Zone People Occupant Count,timestep;


and those in the variables.cfg file are:

<variable source="EnergyPlus">
<EnergyPlus name="WEST ZONE" type="Zone People Occupant Count"/>
</variable>


On starting the simulation in bcvtb an error occurs. The error logged in the .err file is mentioned above. Note that here "WEST ZONE" is the name of one of the zones.

Can someone please tell me about the mistake i am making and also the correct procedure to extract the information about the number of people in a zone at a time step.

Edit: The complete eplusProgram.err file is as follows:

Program Version,EnergyPlus, Version 8.5.0-c87e61b44b, YMD=2018.01.18 18:34,IDD_Version 8.5.0
** Warning ** Weather file location will be used rather than entered (IDF) Location object.
**   ~~~   ** ..Location object=CHICAGO_IL_USA TMY2-94846
**   ~~~   ** ..Weather File Location=New Delhi Delhi IND ISHRAE WMO#=421820
**   ~~~   ** ..due to location differences, Latitude difference=[13.20] degrees, Longitude difference=[164.95] degrees.
**   ~~~   ** ..Time Zone difference=[11.5] hour(s), Elevation difference=[13.68] percent, [26.00] meters.
** Warning ** The Standard Ratings is calculated for Coil:Cooling:DX:SingleSpeed = ACDXCOIL 1 but not at the AHRI test condition due to curve out of bound.
**   ~~~   **  Review the Standard Ratings calculations in the Engineering Reference for this coil type. Also, use Output:Diagnostics, DisplayExtraWarnings for further guidance.
** Warning ** The Standard Ratings is calculated for Coil:Cooling:DX:SingleSpeed = ACDXCOIL 2 but not at the AHRI test condition due to curve out of bound.
**   ~~~   **  Review the Standard Ratings calculations in the Engineering Reference for this coil type. Also, use Output:Diagnostics, DisplayExtraWarnings for further guidance.
** Warning ** The Standard Ratings is calculated for Coil:Cooling:DX:SingleSpeed = ACDXCOIL 3 but not at the AHRI test condition due to curve out of bound.
**   ~~~   **  Review the Standard Ratings calculations in the Engineering Reference for this coil type. Also, use Output:Diagnostics, DisplayExtraWarnings for further guidance.
************* Testing Individual Branch Integrity
************* All Branches passed integrity testing ...
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@Akash could you post the eplusout.err file?

( 2018-01-18 01:14:51 -0500 )edit

@Avi. Thanks a lot for your response. I hope you wanted the .err file of the energy plus simulation. I've added that above. Actually i am very new to using the software and have been trying to learn by looking at the examples available. The above issue is a little surprising. I was working on getting another variable which worked earlier but when i tried to replicate the same it gave a similar error as above. Help will be appreciated!

( 2018-01-18 07:12:12 -0500 )edit

@Akash Start by looking into the .rdd file and find out if Zone People Occupant Count is a valid variable name.

( 2018-01-18 07:31:18 -0500 )edit

Also check the west zone to make sure you have a People object associated with that zone.

( 2018-01-18 07:41:20 -0500 )edit

The following line is present in the .rdd file: Zone,Average,Zone People Occupant Count []
So probably that means that it is a valid variable.

and the following lines are present as part of the .idf file:

West Zone People, !- Name

West Zone, !- Zone or ZoneList Name

Office Occupancy, !- Number of People Schedule Name

Which means that there is a people object associated with that particular zone.

Is there anything else i can do?

( 2018-01-18 09:04:03 -0500 )edit

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The report variables for Zone People Occupant Count is associated with the People object, not the zone. Change the key value to West Zone People.

Regarding the Standard Ratings warnings, the performance curve values do not allow the model to extrapolate the data outside the min/max value of x (indoor WB) and y (outdoor DB) range specified. You can safely (usually) adjust those values to include the rating point. See Engineering Reference document, section Standard Rating of Single-Speed DX Cooling Coils for the rating points.

Curve:Biquadratic,
SPACE1-1 PTAC Cooling Coil Cap-FT,                       !- Name
0.942587793,                                             !- Coefficient1 Constant
0.009543347,                                             !- Coefficient2 x
0.00068377,                                              !- Coefficient3 x**2
-0.011042676,                                            !- Coefficient4 y
0.000005249,                                             !- Coefficient5 y**2
-0.00000972,                                             !- Coefficient6 x*y
12.77778,                                                !- Minimum Value of x
23.88889,                                                !- Maximum Value of x
18.0,                                                    !- Minimum Value of y
46.11111;                                                !- Maximum Value of y

more

@rraustad Could you explain where in the IO Reference or elsewhere you can find which object is associated with a report variable?

( 2018-01-23 12:11:05 -0500 )edit
2

At the end of each object in the Input Output Reference document is a section called Output. Look for what variables are available there. For example, at the end of the People object, on V8.8 pg 467 is the section called Outputs.

( 2018-01-23 13:54:46 -0500 )edit

@rraustad So in order to know which variable available in my model I have to look at the .rdd file but to know which object to use for that variable key I need to look in the IO reference. Is that correct?

( 2018-01-23 14:04:27 -0500 )edit
1

Yes. The good news is you can search for the output variable name and it should take you right to the object. Over time, you will learn which variable key is needed and not have to reference the IO Ref.

( 2018-01-23 14:09:01 -0500 )edit

Is it really true that "Zone People Occupant Count" is associated with "People" object? I'm aware how I/O reference is being written but my actual testing shows,

• "Zone People Occupant Count" associated with "Zone" object (using EMS Sensor)
• "People Occupant Count" associated with "People" object (using EMS Sensor)
• "People Count Design Level" associated with "People" object (using EMS Internal Variable)
( 2019-04-15 10:33:56 -0500 )edit