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Plant Component Availability Schedule

asked 2015-12-22 17:12:50 -0500

What is the recommended approach to schedule the availability of individual plant components in EnergyPlus? An example use case (contrived) might be a plant with two chillers in parallel and you want both scheduled to be available in the summer, but perhaps only one of them available in the winter. I admit this is a contrived example, but I think it clarifies the question as simply as possible.

My question is motivated by this related OpenStudio question. @aparker answered half of the question about plant load range operation schemes, but we really don't have a good answer for how to schedule availability of individual components in OpenStudio. E+ has availability managers that operate at the system level, but that doesn't give us component level control. There is also an availability schedule assigned to each plant operation scheme via the operation schemes list. It is my belief that this is about as close as you can get to component level scheduling, but I'd like some confirmation from the E+ community.

Ultimately we want to add some capability to OS in this area, and I'm trying to research the best path forward.

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answered 2015-12-23 01:47:55 -0500

Chandan Sharma gravatar image

updated 2016-01-11 01:48:56 -0500

One approach which is illustrated by several example files is by having different plant equipment operation schemes (and associated plant equipment list) for on peak and off peak period. If others know a better approach, please chime in. The example below is from VAVSingleDuctReheat.idf.

  Schedule:Compact,
    On Peak,                 !- Name
    Fraction,                !- Schedule Type Limits Name
    Through: 12/31,          !- Field 1
    For: Alldays,            !- Field 2
    Until: 9:00,0.00,        !- Field 3
    Until: 18:00,1.00,       !- Field 5
    Until: 24:00,0.00;       !- Field 7

  Schedule:Compact,
    Off Peak,                !- Name
    Fraction,                !- Schedule Type Limits Name
    Through: 12/31,          !- Field 1
    For: Alldays,            !- Field 2
    Until: 9:00,1.00,        !- Field 3
    Until: 18:00,0.00,       !- Field 5
    Until: 24:00,1.00;       !- Field 7

  PlantEquipmentOperationSchemes,
    CW Loop Operation,       !- Name
    PlantEquipmentOperation:CoolingLoad,  !- Control Scheme 1 Object Type
    Peak Operation,          !- Control Scheme 1 Name
    On Peak,                 !- Control Scheme 1 Schedule Name
    PlantEquipmentOperation:CoolingLoad,  !- Control Scheme 2 Object Type
    Off Peak Operation,      !- Control Scheme 2 Name
    Off Peak;                !- Control Scheme 2 Schedule Name

  PlantEquipmentOperation:CoolingLoad,
    Peak Operation,          !- Name
    0,                       !- Load Range 1 Lower Limit {W}
    70000,                   !- Load Range 1 Upper Limit {W}
    Chiller Plant,           !- Range 1 Equipment List Name
    70000,                   !- Load Range 2 Lower Limit {W}
    245000,                  !- Load Range 2 Upper Limit {W}
    Chiller Plant and Purchased,  !- Range 2 Equipment List Name
    245000,                  !- Load Range 3 Lower Limit {W}
    500000,                  !- Load Range 3 Upper Limit {W}
    Purchased Only;          !- Range 3 Equipment List Name

  PlantEquipmentOperation:CoolingLoad,
    Off Peak Operation,      !- Name
    0,                       !- Load Range 1 Lower Limit {W}
    900000,                  !- Load Range 1 Upper Limit {W}
    All Chillers;            !- Range 1 Equipment List Name

  PlantEquipmentList,
    Chiller Plant,           !- Name
    Chiller:ConstantCOP,     !- Equipment 1 Object Type
    Little Chiller;          !- Equipment 1 Name

  PlantEquipmentList,
    Chiller Plant and Purchased,  !- Name
    Chiller:Electric,        !- Equipment 1 Object Type
    Big Chiller,             !- Equipment 1 Name
    DistrictCooling,         !- Equipment 2 Object Type
    Purchased Cooling;       !- Equipment 2 Name

  PlantEquipmentList,
    Purchased Only,          !- Name
    DistrictCooling,         !- Equipment 1 Object Type
    Purchased Cooling;       !- Equipment 1 Name

  PlantEquipmentList,
    All Chillers,            !- Name
    Chiller:Electric,        !- Equipment 1 Object Type
    Big Chiller,             !- Equipment 1 Name
    Chiller:ConstantCOP,     !- Equipment 2 Object Type
    Little Chiller;          !- Equipment 2 Name

(Note: There are example files which have same control scheme name "Peak Operation" for both 'On Peak' and 'Off Peak' schedule. I am not sure whether this is as intended or a defect in exmaple files. HeatRecoveryElectricChiller.idf, CoolingTower.idf etc. to name a few but I am sure there are more such files. Posted another question on UnmetHours which highlights the above issue.)

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Asked: 2015-12-22 17:12:50 -0500

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Last updated: Jan 11 '16