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asked 2017-06-14 04:09:26 -0600

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Why is the result of plantloop operation incompatible with the strategy specified in EMS:Program?

I used an EMS:Program(see the following blockquote) to control the operation of PlantLoop. In short, the program will decide the number of chillers to stage on according the cooling demand. ( 1chiller if demand is between [0,Cap], and 2 chillers if demand is between [Cap, 2Cap]) Cap here means the rated capacity of the chiller and is 1481477 in this case.

EnergyManagementSystem:Program,
    Cooling_dispatch_Values, !- Name
    IF  CoolSys1_LoopDmnd < -1481477,  !- Program Line 1
        SET Chil1_Disptch = CoolSys1_LoopDmnd/2,  !- Program Line 2
        SET Chil2_Disptch = CoolSys1_LoopDmnd/2,  !- A4
   ELSEIF CoolSys1_LoopDmnd < 0,  !- A5
      SET Chil1_Disptch =  CoolSys1_LoopDmnd,  !- A6
      SET Chil2_Disptch = 0.0, !- A7
ELSE,                    !- A8
     SET Chil1_Disptch = 0.0, !- A9
     SET Chil2_Disptch = 0.0, !- A10
ENDIF;                   !- A11

However, the result is confusing in that even if the cooling demand is larger than 1481477(rated cap), there are still some moments when only one chiller is turned on. Parts of these inconsistencies are shown in the following table.

-------------------------------------------------------------------------------
Date/Time          coolingDmnd    Ele-PowerOfchil1   Ele-PowerOfchil2 
01/01  08:35:00     1484323.003      106556.5292              0
01/01  10:11:15     1493364.145      110266.0414              0
01/01  10:15:00     1488649.626      109615.4136              0
01/01  11:12:16     1499195.511      110652.2023              0
01/01  11:53:10     1502321.217      110640.5195              0
01/01  12:26:15     1514519.749      111723.4092              0
01/01  12:43:38     1502297.995      110866.6415              0
01/01  13:03:19     1506863.348      109632.451               0
01/01  15:17:08     1514534.598      110532.2262              0
01/01  16:12:30     1515863.384      112271.376               0
01/02  05:45:00     1490389.698      107734.7433              0
01/02  06:10:00     1508263.231      109458.4895              0

So why do these situations occur, and how can I avoid these situations?

Any help will be greatly appreciated.

Why is the result of plantloop operation incompatible with the strategy specified in EMS:Program?

I used an EMS:Program(see the following blockquote) to control the operation of PlantLoop. In short, the program will decide the number of chillers to stage on according the cooling demand. ( 1chiller if demand is between [0,Cap], and 2 chillers if demand is between [Cap, 2Cap]) Cap here means the rated capacity of the chiller and is 1481477 in this case.

EnergyManagementSystem:Program,
    Cooling_dispatch_Values, !- Name
    IF  CoolSys1_LoopDmnd < -1481477,  !- Program Line 1
        SET Chil1_Disptch = CoolSys1_LoopDmnd/2,  !- Program Line 2
        SET Chil2_Disptch = CoolSys1_LoopDmnd/2,  !- A4
   ELSEIF CoolSys1_LoopDmnd < 0,  !- A5
      SET Chil1_Disptch =  CoolSys1_LoopDmnd,  !- A6
      SET Chil2_Disptch = 0.0, !- A7
ELSE,                    !- A8
     SET Chil1_Disptch = 0.0, !- A9
     SET Chil2_Disptch = 0.0, !- A10
ENDIF;                   !- A11

However, the result is confusing in that even if the cooling demand is larger than 1481477(rated cap), there are still some moments when only one chiller is turned on. Parts of these inconsistencies are shown in the following table.

-------------------------------------------------------------------------------
Date/Time          coolingDmnd    Ele-PowerOfchil1   Ele-PowerOfchil2 
01/01  08:35:00     1484323.003      106556.5292              0
01/01  10:11:15     1493364.145      110266.0414              0
01/01  10:15:00     1488649.626      109615.4136              0
01/01  11:12:16     1499195.511      110652.2023              0
01/01  11:53:10     1502321.217      110640.5195              0
01/01  12:26:15     1514519.749      111723.4092              0
01/01  12:43:38     1502297.995      110866.6415              0
01/01  13:03:19     1506863.348      109632.451               0
01/01  15:17:08     1514534.598      110532.2262              0
01/01  16:12:30     1515863.384      112271.376               0
01/02  05:45:00     1490389.698      107734.7433              0
01/02  06:10:00     1508263.231      109458.4895              0

So why do these situations occur, and how can I avoid these situations?

Any help will be greatly appreciated.

Updated I have uploaded the .idf file to Github(ASHRAE90.1_OfficeLarge_STD2013_Miami_V1.idf in this repository: https://github.com/faithefeng/EnergyPlus-Note.git) . This model is a prototypical building in Miami as indicated by file name, and I have modified the control scheme for Plant Loop using EMS.

Why is the result of plantloop operation incompatible with the strategy specified in EMS:Program?

I used an EMS:Program(see the following blockquote) to control the operation of PlantLoop. In short, the program will decide the number of chillers to stage on according the cooling demand. ( 1chiller if demand is between [0,Cap], and 2 chillers if demand is between [Cap, 2Cap]) Cap here means the rated capacity of the chiller and is 1481477 in this case.

EnergyManagementSystem:Program,
    Cooling_dispatch_Values, !- Name
    IF  CoolSys1_LoopDmnd < -1481477,  !- Program Line 1
        SET Chil1_Disptch = CoolSys1_LoopDmnd/2,  !- Program Line 2
        SET Chil2_Disptch = CoolSys1_LoopDmnd/2,  !- A4
   ELSEIF CoolSys1_LoopDmnd < 0,  !- A5
      SET Chil1_Disptch =  CoolSys1_LoopDmnd,  !- A6
      SET Chil2_Disptch = 0.0, !- A7
ELSE,                    !- A8
     SET Chil1_Disptch = 0.0, !- A9
     SET Chil2_Disptch = 0.0, !- A10
ENDIF;                   !- A11

However, the result is confusing in that even if the cooling demand is larger than 1481477(rated cap), there are still some moments when only one chiller is turned on. Parts of these inconsistencies are shown in the following table.

-------------------------------------------------------------------------------
Date/Time          coolingDmnd    Ele-PowerOfchil1   Ele-PowerOfchil2 
01/01  08:35:00     1484323.003      106556.5292              0
01/01  10:11:15     1493364.145      110266.0414              0
01/01  10:15:00     1488649.626      109615.4136              0
01/01  11:12:16     1499195.511      110652.2023              0
01/01  11:53:10     1502321.217      110640.5195              0
01/01  12:26:15     1514519.749      111723.4092              0
01/01  12:43:38     1502297.995      110866.6415              0
01/01  13:03:19     1506863.348      109632.451               0
01/01  15:17:08     1514534.598      110532.2262              0
01/01  16:12:30     1515863.384      112271.376               0
01/02  05:45:00     1490389.698      107734.7433              0
01/02  06:10:00     1508263.231      109458.4895              0

So why do these situations occur, and how can I avoid these situations?

Any help will be greatly appreciated.

Updated Updated

I have uploaded the .idf file to Github(ASHRAE90.1_OfficeLarge_STD2013_Miami_V1.idf in this repository: https://github.com/faithefeng/EnergyPlus-Note.git) . This model is a prototypical building in Miami as indicated by file name, and I have modified the control scheme for Plant Loop using EMS.

Why is the result of plantloop operation incompatible with the strategy specified in EMS:Program?

I used an EMS:Program(see the following blockquote) to control the operation of PlantLoop. In short, the program will decide the number of chillers to stage on according the cooling demand. ( 1chiller if demand is between [0,Cap], and 2 chillers if demand is between [Cap, 2Cap]) Cap here means the rated capacity of the chiller and is 1481477 in this case.

EnergyManagementSystem:Program,
    Cooling_dispatch_Values, !- Name
    IF  CoolSys1_LoopDmnd < -1481477,  !- Program Line 1
        SET Chil1_Disptch = CoolSys1_LoopDmnd/2,  !- Program Line 2
        SET Chil2_Disptch = CoolSys1_LoopDmnd/2,  !- A4
   ELSEIF CoolSys1_LoopDmnd < 0,  !- A5
      SET Chil1_Disptch =  CoolSys1_LoopDmnd,  !- A6
      SET Chil2_Disptch = 0.0, !- A7
ELSE,                    !- A8
     SET Chil1_Disptch = 0.0, !- A9
     SET Chil2_Disptch = 0.0, !- A10
ENDIF;                   !- A11

However, the result is confusing in that even if the cooling demand is larger than 1481477(rated cap), there are still some moments when only one chiller is turned on. Parts of these inconsistencies are shown in the following table.

-------------------------------------------------------------------------------
----------------Table1-----------------------------------------------------------
Date/Time          coolingDmnd    Ele-PowerOfchil1   Ele-PowerOfchil2 
01/01  08:35:00     1484323.003      106556.5292              0
01/01  10:11:15     1493364.145      110266.0414              0
01/01  10:15:00     1488649.626      109615.4136              0
01/01  11:12:16     1499195.511      110652.2023              0
01/01  11:53:10     1502321.217      110640.5195              0
01/01  12:26:15     1514519.749      111723.4092              0
01/01  12:43:38     1502297.995      110866.6415              0
01/01  13:03:19     1506863.348      109632.451               0
01/01  15:17:08     1514534.598      110532.2262              0
01/01  16:12:30     1515863.384      112271.376               0
01/02  05:45:00     1490389.698      107734.7433              0
01/02  06:10:00     1508263.231      109458.4895              0

So why do these situations occur, and how can I avoid these situations?

Any help will be greatly appreciated.

Updated

I have uploaded the .idf file to Github(ASHRAE90.1_OfficeLarge_STD2013_Miami_V1.idf in this repository: https://github.com/faithefeng/EnergyPlus-Note.git) . This model is a prototypical building in Miami as indicated by file name, and I have modified the control scheme for Plant Loop using EMS.

Updated 2

I have used the EDD to trace the Erl Program. Here is one record of these inconsistencies.

COOLING_DISPATCH_VALUES,Line 1,SET AA = COOLSYS1_LOOPDMND,-1484323.002751, Occurrence info=Miami Intl Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35
COOLING_DISPATCH_VALUES,Line 2,IF  COOLSYS1_LOOPDMND < -1481477,1.000000, Occurrence info=Miami Intl 
   Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35
COOLING_DISPATCH_VALUES,Line 3,SET CHIL1_DISPTCH = COOLSYS1_LOOPDMND/2,-742161.501375, Occurrence  info=Miami Intl Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35
COOLING_DISPATCH_VALUES,Line 4,SET CHIL2_DISPTCH = COOLSYS1_LOOPDMND/2,-742161.501375, Occurrence info=Miami Intl Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35

As shown, both ChIL1_DISPTCH and ChIL2_DISPTCH are -742161.501375, which means at this moment(01/01 08:32 - 08:35), both these two chillers are turned on. But the confusing part is that in the output files only chiller1 is used( see table1)

Why is the result of plantloop operation incompatible with the strategy specified in EMS:Program?

I used an EMS:Program(see the following blockquote) to control the operation of PlantLoop. In short, the program will decide the number of chillers to stage on according the cooling demand. ( 1chiller if demand is between [0,Cap], and 2 chillers if demand is between [Cap, 2Cap]) Cap here means the rated capacity of the chiller and is 1481477 in this case.

EnergyManagementSystem:Program,
    Cooling_dispatch_Values, !- Name
    IF  CoolSys1_LoopDmnd < -1481477,  !- Program Line 1
        SET Chil1_Disptch = CoolSys1_LoopDmnd/2,  !- Program Line 2
        SET Chil2_Disptch = CoolSys1_LoopDmnd/2,  !- A4
   ELSEIF CoolSys1_LoopDmnd < 0,  !- A5
      SET Chil1_Disptch =  CoolSys1_LoopDmnd,  !- A6
      SET Chil2_Disptch = 0.0, !- A7
ELSE,                    !- A8
     SET Chil1_Disptch = 0.0, !- A9
     SET Chil2_Disptch = 0.0, !- A10
ENDIF;                   !- A11

However, the result is confusing in that even if the cooling demand is larger than 1481477(rated cap), there are still some moments when only one chiller is turned on. Parts of these inconsistencies are shown in the following table.

----------------Table1-----------------------------------------------------------
Date/Time          coolingDmnd    Ele-PowerOfchil1   Ele-PowerOfchil2 
01/01  08:35:00     1484323.003      106556.5292              0
01/01  10:11:15     1493364.145      110266.0414              0
01/01  10:15:00     1488649.626      109615.4136              0
01/01  11:12:16     1499195.511      110652.2023              0
01/01  11:53:10     1502321.217      110640.5195              0
01/01  12:26:15     1514519.749      111723.4092              0
01/01  12:43:38     1502297.995      110866.6415              0
01/01  13:03:19     1506863.348      109632.451               0
01/01  15:17:08     1514534.598      110532.2262              0
01/01  16:12:30     1515863.384      112271.376               0
01/02  05:45:00     1490389.698      107734.7433              0
01/02  06:10:00     1508263.231      109458.4895              0

So why do these situations occur, and how can I avoid these situations?

Any help will be greatly appreciated.

Updated

I have uploaded the .idf file to Github(ASHRAE90.1_OfficeLarge_STD2013_Miami_V1.idf in this repository: https://github.com/faithefeng/EnergyPlus-Note.git) . This model is a prototypical building in Miami as indicated by file name, and I have modified the control scheme for Plant Loop using EMS.

Updated 2

I have used the EDD to trace the Erl Program. Here is one record of these inconsistencies.

COOLING_DISPATCH_VALUES,Line 1,SET AA = COOLSYS1_LOOPDMND,-1484323.002751, Occurrence info=Miami Intl Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35
COOLING_DISPATCH_VALUES,Line 2,IF  COOLSYS1_LOOPDMND < -1481477,1.000000, Occurrence info=Miami Intl 
   Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35
COOLING_DISPATCH_VALUES,Line 3,SET CHIL1_DISPTCH = COOLSYS1_LOOPDMND/2,-742161.501375, Occurrence  info=Miami Intl Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35
COOLING_DISPATCH_VALUES,Line 4,SET CHIL2_DISPTCH = COOLSYS1_LOOPDMND/2,-742161.501375, Occurrence info=Miami Intl Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35

As shown, both ChIL1_DISPTCH and ChIL2_DISPTCH are -742161.501375, which means at this moment(01/01 08:32 - 08:35), both these two chillers are turned on. But the confusing part is that in the output files only chiller1 is used( see table1)table1). How could this be so?

click to hide/show revision 6
retagged

updated 2017-06-15 14:37:30 -0600

__AmirRoth__'s avatar

Why is the result of plantloop operation incompatible with the strategy specified in EMS:Program?

I used an EMS:Program(see the following blockquote) to control the operation of PlantLoop. In short, the program will decide the number of chillers to stage on according the cooling demand. ( 1chiller if demand is between [0,Cap], and 2 chillers if demand is between [Cap, 2Cap]) Cap here means the rated capacity of the chiller and is 1481477 in this case.

EnergyManagementSystem:Program,
    Cooling_dispatch_Values, !- Name
    IF  CoolSys1_LoopDmnd < -1481477,  !- Program Line 1
        SET Chil1_Disptch = CoolSys1_LoopDmnd/2,  !- Program Line 2
        SET Chil2_Disptch = CoolSys1_LoopDmnd/2,  !- A4
   ELSEIF CoolSys1_LoopDmnd < 0,  !- A5
      SET Chil1_Disptch =  CoolSys1_LoopDmnd,  !- A6
      SET Chil2_Disptch = 0.0, !- A7
ELSE,                    !- A8
     SET Chil1_Disptch = 0.0, !- A9
     SET Chil2_Disptch = 0.0, !- A10
ENDIF;                   !- A11

However, the result is confusing in that even if the cooling demand is larger than 1481477(rated cap), there are still some moments when only one chiller is turned on. Parts of these inconsistencies are shown in the following table.

----------------Table1-----------------------------------------------------------
Date/Time          coolingDmnd    Ele-PowerOfchil1   Ele-PowerOfchil2 
01/01  08:35:00     1484323.003      106556.5292              0
01/01  10:11:15     1493364.145      110266.0414              0
01/01  10:15:00     1488649.626      109615.4136              0
01/01  11:12:16     1499195.511      110652.2023              0
01/01  11:53:10     1502321.217      110640.5195              0
01/01  12:26:15     1514519.749      111723.4092              0
01/01  12:43:38     1502297.995      110866.6415              0
01/01  13:03:19     1506863.348      109632.451               0
01/01  15:17:08     1514534.598      110532.2262              0
01/01  16:12:30     1515863.384      112271.376               0
01/02  05:45:00     1490389.698      107734.7433              0
01/02  06:10:00     1508263.231      109458.4895              0

So why do these situations occur, and how can I avoid these situations?

Any help will be greatly appreciated.

Updated

I have uploaded the .idf file to Github(ASHRAE90.1_OfficeLarge_STD2013_Miami_V1.idf in this repository: https://github.com/faithefeng/EnergyPlus-Note.git) . This model is a prototypical building in Miami as indicated by file name, and I have modified the control scheme for Plant Loop using EMS.

Updated 2

I have used the EDD to trace the Erl Program. Here is one record of these inconsistencies.

COOLING_DISPATCH_VALUES,Line 1,SET AA = COOLSYS1_LOOPDMND,-1484323.002751, Occurrence info=Miami Intl Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35
COOLING_DISPATCH_VALUES,Line 2,IF  COOLSYS1_LOOPDMND < -1481477,1.000000, Occurrence info=Miami Intl 
   Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35
COOLING_DISPATCH_VALUES,Line 3,SET CHIL1_DISPTCH = COOLSYS1_LOOPDMND/2,-742161.501375, Occurrence  info=Miami Intl Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35
COOLING_DISPATCH_VALUES,Line 4,SET CHIL2_DISPTCH = COOLSYS1_LOOPDMND/2,-742161.501375, Occurrence info=Miami Intl Ap FL USA TMY3 WMO#=722020, 01/01 08:32 - 08:35

As shown, both ChIL1_DISPTCH and ChIL2_DISPTCH are -742161.501375, which means at this moment(01/01 08:32 - 08:35), both these two chillers are turned on. But the confusing part is that in the output files only chiller1 is used( see table1). How could this be so?

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