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2023-08-21 02:56:15 -0500 received badge  Notable Question (source)
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2022-03-21 09:19:24 -0500 received badge  Popular Question (source)
2021-04-29 15:12:22 -0500 marked best answer Using the Indoor Air Quality option for DCV, why isn't the zone CO2 setpoint achieved?

In Energy Plus, I am using the Indoor Air Quality (Contaminant concentration modeling) approach to simulate DCV. The zone CO2 setpoint of 1100 ppm is not met.

Below are graphs for one system, showing a "high" occupancy day in the first graph, and a "normal" occupancy day followed by two "low" occupancy days in the second graph; system cfm flow is plotted the left axis (blue = mixed air, orange = outside air) and zone C02 ppm (yellow) on the right axis. Looking at these it seems to me that although the zone CO2 setpoint is not met, the system airflow will not increase above what would be provided for space conditioning. On the "normal" day graph, the outside air (orange) is capped at the system minimum flow rate (sum of all connected terminal min flows). On the "high" day graph, the system flow increases above the system minimum, but this seems to be driven by space load rather than by CO2 concentration, as the zone CO2 setpoint is still not met.

"high" occupancy day:

image description

"Normal" followed by two "low" occupancy days:

image description

I found this post that I think is related, regarding using EMS to increase zone flow due to CO2 concentration. Is EMS the only way to do this?

As requested, here are some representative objects related to the DCV setup from my file:

DesignSpecification:OutdoorAir,
Exhall_OA,               !- Name
Sum,                     !- Outdoor Air Method
0.0031,                  !- Outdoor Air Flow per Person {m3/s-person}
0.0004;                  !- Outdoor Air Flow per Zone Floor Area {m3/s-m2}

ZoneControl:ContaminantController,
ExHallB2 DCV,            !- Name
ExHallB2:ExHallB2,       !- Zone Name
ALL ON,                  !- Carbon Dioxide Control Availability Schedule Name
Indoor CO2 Setpoint;     !- Carbon Dioxide Setpoint Schedule Name

Schedule:Constant,
Indoor CO2 Setpoint,     !- Name
Any Number,              !- Schedule Type Limits Name
1100;                    !- Hourly Value

Sizing:Zone,
ExHallB2:ExHallB2,       !- Zone or ZoneList Name
SupplyAirTemperature,    !- Zone Cooling Design Supply Air Temperature Input Method
15.3,                    !- Zone Cooling Design Supply Air Temperature {C}
,                        !- Zone Cooling Design Supply Air Temperature Difference {deltaC}
TemperatureDifference,   !- Zone Heating Design Supply Air Temperature Input Method
,                        !- Zone Heating Design Supply Air Temperature {C}
11,                      !- Zone Heating Design Supply Air Temperature Difference {deltaC}
0.0084,                  !- Zone Cooling Design Supply Air Humidity Ratio {kgWater/kgDryAir}
0.0026,                  !- Zone Heating Design Supply Air Humidity Ratio {kgWater/kgDryAir}
ExHall_OA,               !- Design Specification Outdoor Air Object Name
,                        !- Zone Heating Sizing Factor
,                        !- Zone Cooling Sizing Factor
DesignDay,               !- Cooling Design Air Flow Method
,                        !- Cooling Design Air Flow Rate {m3/s}
,                        !- Cooling Minimum Air Flow per Zone Floor Area {m3/s-m2}
,                        !- Cooling Minimum Air Flow {m3/s}
,                        !- Cooling Minimum Air Flow Fraction
DesignDay,               !- Heating Design Air Flow Method
,                        !- Heating Design Air Flow Rate {m3/s}
,                        !- Heating Maximum Air Flow per Zone Floor Area {m3/s-m2}
,                        !- Heating Maximum Air Flow {m3/s}
,                        !- Heating Maximum Air Flow Fraction
DSZAD;                   !- Design Specification Zone Air Distribution Object Name

Controller:OutdoorAir,
BF VAV System OA Controller,  !- Name
BF VAV System Relief Air Outlet,  !- Relief Air Outlet Node Name
BF VAV System Return Fan Outlet,  !- Return Air Node Name
BF VAV System Mixed Air Outlet,  !- Mixed Air ...
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2019-05-08 10:13:25 -0500 received badge  Popular Question (source)
2018-07-16 16:54:40 -0500 edited answer Designbuilder/EnergyPlus Relief fan

I found your question because I have the same one. In Energy Plus, I was able to add a relief fan as a component on the

2018-07-16 16:53:31 -0500 answered a question Designbuilder/EnergyPlus Relief fan

I found your question because I have the same one. In Energy Plus, I was able to add a relief fan as a component on the

2018-05-17 10:16:27 -0500 commented answer Error importing ESO file

Also check if you have used “Detailed” reporting frequency for any of the requested output variables in the INP file. I’

2018-04-24 19:28:19 -0500 asked a question How to prevent Energy Plus Heat-Only Fan Coil Heating Coil from operating during call for cooling

How to prevent Energy Plus Heat-Only Fan Coil Heating Coil from operating during call for cooling I have a model with so

2018-04-24 10:58:56 -0500 edited question How to prevent Energy Plus Heat-Only Fan Coil Heating Coil from operating during call for cooling

How to prevent Energy Plus Heat-Only Fan Coil Heating Coil from operating during call for cooling My model has electric,

2018-04-24 10:56:10 -0500 asked a question How to prevent Energy Plus Heat-Only Fan Coil Heating Coil from operating during call for cooling

How to prevent Energy Plus Heat-Only Fan Coil Heating Coil from operating during call for cooling My model has electric,

2018-04-16 01:08:44 -0500 commented answer Water condenser low temperature, chiller heat recovery

@Aaron Boranian: Okay, I found and followed the approach illustrated in the diagram "Two Tank Solar Heating System Diagr

2018-04-16 01:06:54 -0500 commented answer Water condenser low temperature, chiller heat recovery

@Aaron Boranian: Okay, I found and followed the approach illustrated in the diagram "Two Tank Solar Heating System Diagr

2018-04-16 01:05:39 -0500 commented answer Water condenser low temperature, chiller heat recovery

@Aaron Boranian: Okay, I found and followed the approach illustrated in the diagram "Two Tank Solar Heating System Diagr

2018-04-15 13:44:44 -0500 commented answer Water condenser low temperature, chiller heat recovery

@Aaron Boranian: I don't grasp how heat can be moved from the preheat waterheater with zero heating capacity (PreH WH)

2018-04-15 13:44:01 -0500 commented answer Water condenser low temperature, chiller heat recovery

@Aaron Boranian: I don't grasp how heat can be moved from the preheat waterheater with zero heating capacity (PreH WH)

2018-04-15 13:43:00 -0500 commented answer Water condenser low temperature, chiller heat recovery

@Aaron Boranian: I don't grasp how heat can be moved from the preheat waterheater with zero heating capacity (PreH WH)

2018-04-03 16:01:55 -0500 commented question Why could the EnergyPlus Run Status reported Elapsed Time not equal the Total elapsed clock time?

@David Goldwasser, thanks for this idea. The file is located on local drive of my laptop.

2018-03-28 11:34:25 -0500 commented answer What is the best hardware setup to minimize run time?

@Neal Kruis, Specifically how would one diagnose item #3.Memory, to determine if it is an issue?

2018-03-28 11:17:36 -0500 asked a question Why could the EnergyPlus Run Status reported Elapsed Time not equal the Total elapsed clock time?

Why could the EnergyPlus Run Status reported Elapsed Time not equal the Total elapsed clock time? I have an energy plus

2018-03-16 09:17:05 -0500 edited question What does the EnergyPlus warning "Inside surface heat balance did not converge" mean?

What does the EnergyPlus warning "Inside surface heat balance did not converge" mean? I have an Energy Plus file with th

2018-03-16 09:16:32 -0500 edited question What does the EnergyPlus warning "Inside surface heat balance did not converge" mean?

What does the EnergyPlus warning "Inside surface heat balance did not converge" mean? I have an Energy Plus file with th

2018-03-15 10:51:40 -0500 commented answer What does the EnergyPlus warning "Inside surface heat balance did not converge" mean?

@Avi, thanks for pointing me to that post, which indicates that increasing the timestep may be a solution. I had not fou

2018-03-15 10:51:17 -0500 commented answer What does the EnergyPlus warning "Inside surface heat balance did not converge" mean?

@Avi, thanks for pointing me to that post, which indicates that increasing the timestep may be a solution. I had not fou

2018-03-14 23:55:18 -0500 edited answer Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

I did some experimentation and found that once I split the IDF file into two halves (in a text editor) I was able to sav

2018-03-14 23:55:18 -0500 received badge  Associate Editor (source)
2018-03-14 23:52:33 -0500 marked best answer Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

I have an IDF file that I exported from Design Builder (v.5.3.4.004). The Version listed in the IDF is "8.6.0.001". I would like to open this file in IDFEditor, and save it to get the objects formatted (grouped by class and in the IDF editor format.) When I open it with the IDFEditor v8.6.0, I got a warning that the file format is incompatible with the .IDD file being used, and with the IDFEditor version. I edited the Version to be "8.6" in my text editor, and that warning ceased. The IDF file appears to run fine using EPLaunch v8.6.0 (I am running it now: it was read with no issues....and still simulating fine so far).

BUT, when I try to save the file, it aborts during the process with the error: "Run-time error '9': Subscript out of range", once I click "Okay" on that error, the IDFEditor quits. (I can open the new IDF file that I was attempting to save, and it does contain a incomplete portion of the IDF.

Any ideas how I can solve this?

2018-03-14 23:52:31 -0500 edited answer Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

I did some experimentation and found that once I split the IDF file into two halves (in a text editor) I was able to sav

2018-03-14 16:18:01 -0500 edited question What does the EnergyPlus warning "Inside surface heat balance did not converge" mean?

What does the EnergyPlus warning "Inside surface heat balance did not converge" mean? I have an Energy Plus file with th

2018-03-14 16:17:11 -0500 commented answer Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

Thanks for the help @JasonGlazer!

2018-03-14 16:16:27 -0500 asked a question What does the EnergyPlus warning "Inside surface heat balance did not converge" mean?

What does the EnergyPlus warning "Inside surface heat balance did not converge" mean? I have an Energy Plus file with th

2018-03-13 13:49:32 -0500 commented answer PG&E Cool Tools Chiller tool- Generating Performance Curve E+

@Anna Osborne Brannon, I just noticed that there is a tool in the PreProcess folder of the Energy Plus installation that

2018-03-10 17:30:27 -0500 edited answer Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

I did some experimentation and found that once I split the IDF file into two halves (in a text editor) I was able to sav

2018-03-10 10:16:42 -0500 answered a question Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

I did some experimentation and found that once I split the IDF file into two halves (in a text editor) I was able to sav

2018-03-10 01:36:26 -0500 edited question Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

Why does IDF Editor issue error "Run-time error '9': Subscript out of range" aborting on Save-as? I have an IDF file tha

2018-03-10 01:28:47 -0500 edited question Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

Why does IDF Editor issue error "Run-time error '9': Subscript out of range" on Save-as? I have an IDF file that I expor

2018-03-10 01:23:24 -0500 edited question Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

Why does IDF Editor issue error "Run-time error '9': Subscript out of range" on Save-as? I have an IDF file that I expor

2018-03-10 01:23:04 -0500 edited question Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

Why does IDF Editor issue error "Run-time error '9': Subscript out of range" on Save-as? I have an IDF file that I expor

2018-03-10 01:22:31 -0500 edited question Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

Why does IDF Editor issue error "Run-time error '9': Subscript out of range"? I have an IDF file that I exported from De

2018-03-10 01:21:53 -0500 asked a question Why does IDF Editor issue error "Run-time error '9': Subscript out of range," aborting on Save-as?

Why does IDF Editor issue error "Run-time error '9': Subscript out of range"? I have an IDF file that I exported from De

2018-03-01 15:03:43 -0500 marked best answer What air terminal unit types are allowed on a AirLoopHVAC:Unitary system?

I see that the diagrams in the section of the I/O reference on AirLoopHVAC:UnitarySystemshow only AirTerminal:SingleDuct:Uncontrolled. I have a file built by a colleague (which runs) that uses AirTerminal:SingleDuct:VAV:NoReheat for a zone served by an AirLoopHVAC:UnitarySystem. I am wondering if this is problematic.

2018-03-01 12:40:07 -0500 asked a question What air terminal unit types are allowed on a AirLoopHVAC:Unitary system?

What air terminal unit types are allowed on a AirLoopHVAC:Unitary system? I see that the diagrams in the section of the

2018-03-01 12:13:47 -0500 commented answer Single Zone VAV serving multiple zones

@dradair, did you have any luck finding a solution? I'm looking at the same problem. Did you consider using an AirLoopHV

2018-02-17 15:34:00 -0500 commented question Why is this Energy Plus VAV system operating at maximum airflow when all connected zones require heating?

...The reheat coil in one of the two zones, for example, is at an autosized cap. of ~109kW, whereas the zone predicted s