I followed Brent's directions and set the heating setpoint temperature to a higher value than the zone mean air temperature for the WinterDesignDay only and it worked! The system is properly sized, never turns on and there are no unmet setpoint temperatures.
And this is the schedule:
Schedule:Compact,
Heating Setpoint IndCond Schedule, !- Name
Temperature, !- Schedule Type Limits Name
Through: 12/31, !- Field 1
For: WinterDesignDay, !- Field 2
Until: 24:00, !- Field 3
20, !- Field 4
For: AllOtherDays, !- Field 5
Until: 24:00, !- Field 6
-18; !- Field 7
On 6.12.2012 19:42, Griffith, Brent wrote:
Hi Miroslav,
This error is occurring during sizing of the air handler, not operation. You need the sizing results to not come out zero. Probably want to schedule some loads to be “on” and/or disable whatever indirect conditioning is taking all the load during design day types. Schedules can be setup to define different things to happen for the day types called WinterDesignDay and SummerDesignDay.
Brent
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Miroslav Bratanov
Sent: Thursday, December 06, 2012 6:21 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] AirLoopHVAC has no air flow workaround?
Hello James,
All the zones connected to this air loop have no loads. They are all indirectly conditioned.
I think that if I use normal setpoints with always off availability, it will result in hours with unmet setpoints.
On 6.12.2012 01:39, Jim Dirkes wrote:
Miroslav,
I’m guessing that this is the only air loop… I have modeled other buildings where one or another zone had zero load, but always at least one zone had load – with no fatal errors.
How about using normal setpoints and making the availability always OFF?
James V Dirkes II, PE, BEMP, LEED AP
www.buildingperformanceteam.com
Energy Analysis, Commissioning & Training Services
1631 Acacia Drive, Grand Rapids, MI 49504 USA
616 450 8653
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Miroslav Bratanov
Sent: Wednesday, December 05, 2012 5:15 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] AirLoopHVAC has no air flow workaround?
James,
The program stops before the actual simulation. This is the full message from the .err file.
** Severe ** AirLoopHVAC AHU-RHT_BL has no air flow
** ~~~ ** Check flow rate inputs for components in this air loop and,
** ~~~ ** if autosized, check Sizing:Zone and Sizing:System objects and related inputs.
** Fatal ** Previous condition causes termination.
...Summary of Errors that led to program termination:
..... Reference severe error count=1
..... Last severe error=AirLoopHVAC AHU-RHT_BL has no air flow
************* Warning: Node connection errors not checked - most system input has not been read (see previous warning).
************* Fatal error -- final processing. Program exited before simulations began. See previous error messages.
On 6.12.2012 00:04, Jim Dirkes wrote:
Ignore the “error”. It does not prevent the simulation from running and, as you said, indicates a correct and proper condition.
E+ is just letting you know about an unusual condition.
James V Dirkes II, PE, BEMP, LEED AP
www.buildingperformanceteam.com
Energy Analysis, Commissioning & Training Services
1631 Acacia Drive, Grand Rapids, MI 49504 USA
616 450 8653
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Miroslav Bratanov
Sent: Wednesday, December 05, 2012 4:46 PM
To: EnergyPlus Support
Subject: [EnergyPlus_Support] AirLoopHVAC has no air flow workaround?
Hello all,
I have a building with some indirectly conditioned spaces and I am
modeling a system (PVAV with reheat) just to satisfy the requirement of
Appendix G that all conditioned spaces should be simulated as both
heated and cooled. I set higher and lower setpoint temperatures for the
heating and cooling respectfully, so the system would never turn on. But
during the simulation I get a severe error which says that AirLoopHVAC
has no air flow. Of course this is absolutely correct since there are no
any loads.
I wonder if anyone has had such case and what's the way to deal with
this problem?
Any help is highly appreciated!
Thank you!
Miroslav
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