[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [EnergyPlus_Support] simulation time step
What I mean is that if you use time steps shorter than 1 h Energy Plus is
no more using only real weather data (in my case the ones I measured)
but some artificial ones.
I don't know the interpolation algorythm used by Energy Plus.
Anyhow I guess that it would produce some regular function. If the real trend
is not regular (maybe because of clouds) this procedure could introduce some
errors...
Adriana
At 17.12 06/02/03 -0600, you wrote:
>You say that using a time step shorter than 1 hour "introduce some
>errors because of the interpolation of weather data". Why do say
>that interpolation introduces errors? With a 1 hour time step,
>weather conditions are held constant for an entire hour, and then
>change to something new for the next hour. One could argue that this
>introduces errors, because real weather changes continously across
>each hour. In general, the structure of EnergyPlus is designed to
>respond better using shorter time steps, so that is what I would
>recommend.
>
>Mike
>
>
>
>On 5 Feb 2003, at 10:22, Adriana Angelotti wrote:
>
> > Differences are small if you compare results for time steps shorter
> > than 1h (10m, 15m and 30m). But using 1h as the time step can produce
> > differences of 0.5-1°C in the free floating temperature of a room.
> >
> > I know that weather data is interpolated for time steps shorter than
> > 1h and I guess the difference I see in the results is due to the
> > interpolation. So if I use a short time step I can follow better the
> > dynamic of the building, but I introduce some errors because of the
> > interpolation of weather data. On the other side if I use 1h I'm sure
> > I'm not introducing interpolation errors but maybe I miss something in
> > the dynamic. So I wonder what is the best choice. Thank you
> >
> > Adriana A.
> >
> > At 14.06 04/02/03 -0600, you wrote:
> > >What kind of differences are you seeing? They should be small, and
> > >hourly results should be very similar. The hourly weather data is
> > >interpolated for shorter time steps.
> > >
> > >On 3 Feb 2003, at 14:50, Adriana Angelotti wrote:
> > >
> > > > Hello everybody,
> > > >
> > > > I'm trying to reproduce some experimental data on a free floating
> > > > building with an Energy Plus simulation. I see that using
> > > > different time steps (10m, 15m, 30m and 1h) produces different
> > > > results.
> > > >
> > > > So I wonder if there is some general consideration that can be
> > > > used in the choice of the proper time step, besides the one I
> > > > found on EP manual (15 minutes for a simulation without HVAC and
> > > > 10m for a simulation with HVAC).
> > > >
> > > > Besides this, I wonder what is the meaning of a simulation with a
> > > > time step shorter than 1h, if the weather data time step is 1h.
> > > >
> > > >
> > > > I would appreciate your help.
> > > > Thank you
> > > >
> > > > Adriana Angelotti
> > > >
> > > >
> > > >
> > > > To unsubscribe from this group, send an email to:
> > > > EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
> > > >
> > > > 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 not allowed -- please post any files to the
> > > > appropriate folder in the Files are of the Support Web Site.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Your use of Yahoo! Groups is subject to
> > > > http://docs.yahoo.com/info/terms/
> > > >
> > >
> > >
> > >
> > >========================================================
> > >EnergyPlus Testing and Support
> > >EnergyPlus-Support@xxxxxxxx
> > >
> > >
> > >
> > >To unsubscribe from this group, send an email to:
> > >EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
> > >
> > >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 not allowed -- please post any files to the
> > >appropriate folder in the Files are of the Support Web Site.
> > >
> > >
> > >
> > >
> > >
> > >
> > >Your use of Yahoo! Groups is subject to
> > >http://docs.yahoo.com/info/terms/
> >
> >
> >
> > ------------------------ Yahoo! Groups Sponsor
> > ---------------------~--> Get 128 Bit SSL Encryption!
> > http://us.click.yahoo.com/LIgTpC/vN2EAA/xGHJAA/dkFolB/TM
> > ---------------------------------------------------------------------~
> > ->
> >
> > To unsubscribe from this group, send an email to:
> > EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
> >
> > 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 not allowed -- please post any files to the
> > appropriate folder in the Files are of the Support Web Site.
> >
> >
> >
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >
>
>
>
>To unsubscribe from this group, send an email to:
>EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
>
>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 not allowed -- please post any files to the appropriate
>folder in the Files are of the Support Web Site.
>
>
>
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
------------------------ Yahoo! Groups Sponsor ---------------------~-->
Get 128 Bit SSL Encryption!
http://us.click.yahoo.com/LIgTpC/vN2EAA/xGHJAA/dkFolB/TM
---------------------------------------------------------------------~->
To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
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 not allowed -- please post any files to the appropriate folder in the Files are of the Support Web Site.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/