Xu,
your model has 1023 surfaces, plus 615 fenestration surfaces. Surfaces are rather critical for simulation time, even more than zones. To top this up, you may have inadvertently included natural ventilation in your simulation when setting up the model on Designbuilder, since your idf is showing 1074 multizone:surface objects on airflow network. If you don't need this, retrace back to Designbuilder and uncheck the natural ventilation settings, they should be somewhere in the building model options, I think in the two first tabs of this menu (if my memory serves me right).
Pedro.
On 27-09-2011 4:51, Ke Xu wrote:
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:
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>
> The primary EnergyPlus web site is found at:
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>
> The group web site is:
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>
> Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
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