[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [EnergyPlus_Support] Re: A Problem regarding to Energy Plus Run Time
Hi Ke,
Thanks for reporting back on this, so it sounds like you found that natural ventilation was the main reason for the slow simulation.
I expect that someone from the EnergyPlus team could comment more meaningfully on this, but from what I understand the Airflow network (AFN) is simulated iteratively until convergence at each time step. I'm not sure if there is also an outer loop as well. Anyway from what I hear, E+ v7 due out this October, will bring some significant improvements in simulation speed for AFN models.
Regards,
Andy
Andy Tindale
DesignBuilder Software ltd
www.designbuilder.com
Tel: +44 (0)1453 755500
-----Original Message-----
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Ke Xu
Sent: 29 September 2011 15:18
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: A Problem regarding to Energy Plus Run Time
Hi,Pedro,Andy,
Just a followup on this topic,I tried both senarios: water radiator and convector.Compared with the simulation time of the case with natural ventilation function switched on, which could be weeks, these two simulation can be finished within several hours. So clearly, simulating natural ventilation of a building takes huge amount of time, and this is a very good lesson I learnt. Do you have an idea why natural ventilation adds so much time to the simulation? Is it because it takes more iterations for each time step? or because of the model itself?
Thanks.
Ke
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Ke Xu" <xukevin24@...> wrote:
>
> Pedro, Andy,
> I did find the natural ventilation option in DesignBuilder is accidently turned on somehow, even though I didn't mean to. Thanks for your advise, I am now updating the model and giving it a run.
>
> Thanks again.
>
> Ke
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Andy Tindale <andy.tindale@> wrote:
> >
> > Ke,
> >
> > As mentioned by Pedro, you do have calculated natural ventilation switched on (as well as radiant heating). I understand that E+ v7 includes a big speed up for the airflow network so this shouldn't be so much of a problem in the future. It will be interesting to know after you have made your changes, which of these 2 (nat vent or radiant systems) has the biggest impact on simulation speed in your model.
> >
> > Andy
> >
> > Andy Tindale
> > DesignBuilder Software ltd
> > www.designbuilder.com
> > Tel: +44 (0)1453 755500
> >
> >
> > -----Original Message-----
> > From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Ke Xu
> > Sent: 27 September 2011 04:51
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > Subject: [EnergyPlus_Support] Re: A Problem regarding to Energy Plus Run Time
> >
> > Andy,
> > I did include radiant/baseboard heating system in the model. No natural ventilation, I am now trying to change the heating equipment to water convector and see if there is any difference for the simulation time.
> >
> > Thanks.
> >
> > Ke
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Andy Tindale <andy.tindale@> wrote:
> > >
> > > Hi Ke Xu,
> > >
> > > I haven't had a chance to look at your files but does the model include any radiant heating or cooling systems? These can slow EnergyPlus down. Calculated natural ventilation?
> > >
> > > There is page in the DesignBuilder documentation which discusses some other causes of slow EnergyPlus simulations and approaches which have helped DesignBuilder users to speed up their simulations:
> > >
> > > http://www.designbuilder.co.uk/helpv3/Content/Working_with_Large_Models.htm
> > >
> > > Regards,
> > >
> > > Andy
> > >
> > > Andy Tindale
> > > DesignBuilder Software ltd
> > > www.designbuilder.com
> > > Tel: +44 (0)1453 755500
> > >
> > >
> > > -----Original Message-----
> > > From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Ke Xu
> > > Sent: 26 September 2011 22:53
> > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > Subject: [EnergyPlus_Support] A Problem regarding to Energy Plus Run Time
> > >
> > > Hi,group members,
> > > I have a problem with the simulation run time. I built up a building energy model with detailed HVAC systems using DesignBuilder v3 and convert it to an .idf file in order to simulate it in EnergyPlus.
> > >
> > > Although the simulation could run without fatal error, it did take EnergyPlus quite a few days to finish a whole-year run. The building itself is fairly simple, primarily 1-story, about 28,700ft2 for total area,5 AHUs with chilled and hot water provided by a chiller and a boiler, respectively. Therefore, I am thinking about something inside of the model is not right, or some parts of the building model could be simplified.
> > >
> > > Since it is my first time to build up such a detailed model, I felt that I don't have enough experience to figure out the problem. I uploaded the .idf as "0922detailedHVAC.zip " in the "Files" Zone and can anyone here help me find out the problems, or simplify the model and reduce the amount of calculation time?
> > >
> > > Thanks.
> > >
> > > Best Regards,
> > >
> > > Ke Xu
> > >
> > > Ph.D. Candidate, Graduate Assistant
> > >
> > > Architectural Engineering Department
> > >
> > > Penn State University
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > > Primary EnergyPlus support is found at:
> > > http://energyplus.helpserve.com or send a message to energyplus-support@
> > >
> > > The primary EnergyPlus web site is found at:
> > > http://www.energyplus.gov
> > >
> > > The group web site is:
> > > http://groups.yahoo.com/group/EnergyPlus_Support/
> > >
> > > Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
> > >
> > > EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
> > > Yahoo! Groups Links
> > >
> >
> >
> >
> >
> > ------------------------------------
> >
> > Primary EnergyPlus support is found at:
> > http://energyplus.helpserve.com or send a message to energyplus-support@
> >
> > The primary EnergyPlus web site is found at:
> > http://www.energyplus.gov
> >
> > The group web site is:
> > http://groups.yahoo.com/group/EnergyPlus_Support/
> >
> > Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
> >
> > EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
> > Yahoo! Groups Links
> >
>
------------------------------------
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links
------------------------------------
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/EnergyPlus_Support/join
(Yahoo! ID required)
<*> To change settings via email:
EnergyPlus_Support-digest@xxxxxxxxxxxxxxx
EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx
<*> To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/