RE: [EnergyPlus_Support] Re: Airflow Network

Anisur:

I tested your input file using Chicago weather file. Here are my modifications:

Schedule:Compact,

Minimum OA Sch, !- Name

Temperature, !- Schedule Type Limits Name

Through: 3/31, !- Field 1

For: AllDays, !- Field 2

Until: 24:00, 0.35, !- Field 8

Through: 9/30, !- Field 9

For: AllDays, !- Field 10

Until: 24:00, 0.35, !- Field 12

Through: 12/31, !- Field 13

For: AllDays, !- Field 14

Until: 24:00, 0.35; !- Field 8

AirflowNetwork:MultiZone:Component:DetailedOpening,

WiOpen1, !- Name

0.0001, !- Air Mass Flow Coefficient When Opening is Closed {kg/s-m}

0.65, !- Air Mass Flow Exponent When Opening is Closed {dimensionless}

NonPivoted, !- Type of Rectanguler Large Vertical Opening (LVO)

0.0, !- Extra Crack Length or Height of Pivoting Axis {m}

2, !- Number of Sets of Opening Factor Data

0.0, !- Opening Factor 1 {dimensionless}

0.001, !- Discharge Coefficient for Opening Factor 1 {dimensionless}

0.0, !- Width Factor for Opening Factor 1 {dimensionless}

1.0, !- Height Factor for Opening Factor 1 {dimensionless}

0.0, !- Start Height Factor for Opening Factor 1 {dimensionless}

1.0, !- Opening Factor 2 {dimensionless}

0.01, !- Discharge Coefficient for Opening Factor 2 {dimensionless}

1.0, !- Width Factor for Opening Factor 2 {dimensionless}

1.0, !- Height Factor for Opening Factor 2 {dimensionless}

0.0, !- Start Height Factor for Opening Factor 2 {dimensionless}

0, !- Opening Factor 3 {dimensionless}

0, !- Discharge Coefficient for Opening Factor 3 {dimensionless}

0, !- Width Factor for Opening Factor 3 {dimensionless}

0, !- Height Factor for Opening Factor 3 {dimensionless}

0, !- Start Height Factor for Opening Factor 3 {dimensionless}

0, !- Opening Factor 4 {dimensionless}

0, !- Discharge Coefficient for Opening Factor 4 {dimensionless}

0, !- Width Factor for Opening Factor 4 {dimensionless}

0, !- Height Factor for Opening Factor 4 {dimensionless}

0; !- Start Height Factor for Opening Factor 4 {dimensionless}

I made two changes. The first change was to increase the Minimum Air Flow Fraction in the AirTerminal:SingleDuct:VAV:Reheat objects from 0.1 to 0.35. The second change was to reduce detailed opening flows to small values. The program ran to completion using Chicago weather file.

When a VAV fan is used, the minimum forced flow rate should be much larger than any possible flow rates driven by wind from openings, so that ducted air can flow into designated direction. If the wind driven flow rates from openings have similar magnitude of the forced airflows, the forced airflow may not flow as designated, so that the solver could not find a solution. Therefore, the minimum terminal flow rate should be adjusted accordingly. This is restriction of the solver.

The warning messages also show windows are open during HVAC system operation. A hybrid ventilation control is recommended to avoid simultaneous HVAC operation and window openings. An example file of AirflowNetwork_MultiZone_SmallOffice_VAV.idf may give you a good example to show how to use an AvailabilityManager:HybridVentilation object. The detailed information may be found in the Input Output Reference.

Hope this helps.

Lixing

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Anisur Rahman
Sent: Tuesday, July 30, 2013 6:00 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Re: Airflow Network

Hi,

My Airflow network file giving some error. Could anyone look at the error file (attached) and suggest me how to fix those.

Thank you,

Anisur

Best Regards,

Anisur Rahman

PhD Candidate
College Of Architcture
Illinois Institute of Technology,
Chicago, Illinois.

From: Anisur Rahman <anisur1294@xxxxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Thursday, July 25, 2013 5:38 PM
Subject: Re: [EnergyPlus_Support] Re: Airflow Network

Yes, the problem was the connections in Multiple floors. I made a single floor model and it works.

Thanks for the advice.

Best Regards,

Anisur Rahman

PhD Candidate
College Of Architcture
Illinois Institute of Technology,
Chicago, Illinois.

From: Anisur Rahman <anisur1294@xxxxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Thursday, July 25, 2013 12:11 PM
Subject: Re: [EnergyPlus_Support] Re: Airflow Network

I think that is the most possible reason of this error. Let me try first with a single floor model. If it works, then I will be sure that the problem is input for multiple floors and those are not properly connected.

Thanks for your suggestion and time. I will get back to you soon.

Best Regards,

Anisur Rahman

PhD Candidate
College Of Architcture
Illinois Institute of Technology,
Chicago, Illinois.

From: Edward G. Lyon <eglyon@xxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Thursday, July 25, 2013 11:54 AM
Subject: RE: [EnergyPlus_Support] Re: Airflow Network

I see this is a 15 story building and you use a single mid floor multiple times. I have only used the airflow network with complete models that have all the interconnected spaces modeled. I am not that familiar with the other example files, do any of them a single floor input for multiple floors? If not, your problem may be that things are not properly connected�

Ned Lyon, P.E. (MA, WV)
Staff Consultant

SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct
617.285.2162 mobile
781.907.9009 fax
www.sgh.com

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Anisur Rahman
Sent: Thursday, July 25, 2013 12:39 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Re: Airflow Network

Yes, I increased the number of iterations up to 30000 and convergence limit to 500. It is showing the same error.

Best Regards,

Anisur Rahman

PhD Candidate
College Of Architcture
Illinois Institute of Technology,
Chicago, Illinois.

From: Edward G. Lyon <eglyon@xxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Thursday, July 25, 2013 11:28 AM
Subject: RE: [EnergyPlus_Support] Re: Airflow Network

The default value for number of iterations is 500. Have you tried increasing this or adjusting the convergence criteria?

Ned Lyon, P.E. (MA, WV)
Staff Consultant

SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct
617.285.2162 mobile
781.907.9009 fax
www.sgh.com

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Anisur Rahman
Sent: Thursday, July 25, 2013 12:17 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Re: Airflow Network

Hi Bruno Scalet,

Thanks again.

I tried with INPUT option. But still it is giving the same error. Any further suggestion.

Best Regards,

Anisur Rahman

PhD Candidate
College Of Architcture
Illinois Institute of Technology,
Chicago, Illinois.

From: Bruno Scalet <bruno.scalet@xxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Wednesday, July 24, 2013 4:36 PM
Subject: [EnergyPlus_Support] Re: Airflow Network

Hello,

I had the same problem today. As written in the I/O file, the AirflowNetwork object with "SurfaceAvarageCalculation" option in the field "Wind Pressure Coefficient Type" only supports simple geometry (rectangular or squared ones). If your geometry/envelope is different from it you should use the option "Input" which will require all the pressure entries to this building you are modeling.

I hope I've helped you.

Greetings,

Bruno Scalet