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Problem with Duplicate Name, Overwriting existing object

asked 2021-03-24 08:20:46 -0600

tri.ton99 gravatar image

Hi everyone,

I'm trying to add a fan in relief air from AirLoopHVAC:OutdoorAirSystem to control the ratio between Outdoor air and Return air in mixing box (by control the air flowrate between relief air and mixed air, because I could not place fan in outdoor air and return air). When I added Fan:VariableVolume in Relief Air to the AirLoopHVAC:OutdoorAirSystem:EquipmentList like 5ZoneAirCooledConvCoef.idf (line 2690) but it warned me below:

  • Severe * Duplicate name found. name: "West Zone Relief Fan". Overwriting existing object.

This is my model (I added West Zone Relief Fan to West Data Center OA Equipment).

Thank you all for support and helping me with this problem.

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answered 2021-03-24 08:47:14 -0600

When you tried to add the West Zone Relief Fan to the AirLoopHVAC:OutdoorAirSystem:EquipmentList object, you didn't change the syntax correctly. Here is your object in the IDF you provided:

AirLoopHVAC:OutdoorAirSystem:EquipmentList,
  West Data Center OA Equipment,                  !- Name
  OutdoorAir:Mixer,                               !- Component 1 Object Type
  West Data Center OAM Box;                       !- Component 1 Name
  Fan:VariableVolume,                             !- Component 2 Object Type
  West Zone Relief Fan,                           !- Component 2 Name

The last input field of all EnergyPlus objects should end with a semi-colon (;). You have a semi-colon after only the OutdoorAir:Mixer object's name West Data Center OAM Box, so EnergyPlus thinks that is the end of the OA system equipment list and the next two lines are defining a new Fan:VariableVolume object with the name West Zone Relief Fan. You actually define this fan object on line 1455 in this IDF, which is why EnergyPlus is giving you the severe error of duplicate object name (same VAV fan object type and same name defined in the IDF).

To fix this severe error, you should update this object as follows:

AirLoopHVAC:OutdoorAirSystem:EquipmentList,
  West Data Center OA Equipment,                  !- Name
  OutdoorAir:Mixer,                               !- Component 1 Object Type
  West Data Center OAM Box,                       !- Component 1 Name
  Fan:VariableVolume,                             !- Component 2 Object Type
  West Zone Relief Fan;                           !- Component 2 Name

From the Input Output Reference for the OA system equipment list object, the order that the components are listed is the order that EnergyPlus will simulate their airflow. If it doesn't seem that the relief fan is being controlled correctly, you may want to try switching the order of components in the OA system equipment list (relief fan is component #1, OA mixer is component #2).

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Thank you very much. I did not notice that I missed the end of object with a semi-colon.

It worked.

tri.ton99 gravatar image tri.ton99  ( 2021-03-24 09:32:07 -0600 )edit

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Asked: 2021-03-24 08:20:46 -0600

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Last updated: Mar 24