I am afraid I do not have the expertise to help you further, but there
are papers on the E+ web site that may shed some light on other reasons
for the differences. I think what is more important than the comparison
of one programs output to another is the difference between one
simulation and another using the same program. You should feel
comfortable with this type of result. Take your TRNSYS file and modify
it to create a new building. Then take the E+ file and modify it in the
same way. Then run these new files and compare the two TRNSYS files for
differences in energy use, and then do the same with the two E+ files.
Then compare how close these differences are between these two program.
You may want to read this document:
http://apps1.eere.energy.gov/buildings/energyplus/pdfs/energyplus_ashrae_140_envelope.pdf
And the comparison of capabilities in this document.
http://apps1.eere.energy.gov/buildings/energyplus/bibliography.cfm
Drury B Crawley, Jon W Hand, Michael Kummert, Brent T Griffith. 2005.
"*Contrasting the Capabilities of Building Energy Performance Simulation
Programs*," in /Proceedings of Building Simulation 2005/
<http://www.ibpsa.org/m_bs2005.asp>, 15-18 August 2005, Montreal,
Quebec, Canada. IBPSA. (PDF 105 KB
<http://www.ibpsa.org/proceedings/BS2005/BS05_0231_238.pdf>)
Brouchery Herve wrote:
> No problem. And your inputs may help me explain the last differences I
> observe...
>
> Building features are:
> - size : ground area = 1500m² and h = 3m
> - localized in south of France
> - north window area = 80m² (U=2.95, g=0.77)
> - est and west window area = 50m² (U=1.1, g=0.4)
> - south window area = 45m² (U=2.95, g=0.77)
> - no shading due to environment
> - internal gain (people, light and computers) => both simulators are
> very closed regarding computation of internal gains.
>
> You can find attached an excel file with simulation results (over a
> complete year) for 2 cases (with and without window).
>
> 1) With window:
> After solving the window frame issue, zone transmitted solar energy
> differences seem to be acceptable. What do you think?
> Regarding cooling needs, the biggest differences are observed during
> winter time but the cooling demand is also quite low. Do you have any
> idea to explain this?
>
> 2) Without window:
> The total result over the complete year is very close (1% difference)
> but looking at months individually, we can remark that the errors
> compensate themselves. Do you have any idea to explain this?
>
> Regards
> Herve
>
>
> Message original Re : Re: Re : RE: [EnergyPlus_Support] Energy Plus
> vs TRNSYS
>
> *De : *Richard Raustad <RRaustad@xxxxxxxxxxxx>
> *A : *EnergyPlus_Support@xxxxxxxxxxxxxxx
> *Date* : 2010-07-22 14:37:29
>
>
>
> Would you mind reporting a little more detail on the comparison? How
> close were they? If you remove the windows, how close were they? etc.
>
> Brouchery Herve wrote:
> >
> >
> > Many thanks for your reply.
> > I have finally found the main origin of the difference between both
> > simulators: it was linked to the settings of the window frames...
> > I still observe some minor differences but they should be due now to
> > the model of transmission used, as you mentioned in your email below.
> >
> >
>
> --
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL 32922-5703
> Phone: (321) 638-1454
> Fax: (321) 638-1439 or 1010
> Visit our web site at: http://www.fsec.ucf.edu
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>
--
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
1679 Clearlake Road
Cocoa, FL 32922-5703
Phone: (321) 638-1454
Fax: (321) 638-1439 or 1010
Visit our web site at: http://www.fsec.ucf.edu
UCF - From Promise to Prominence: Celebrating 40 Years