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Re: [EnergyPlus_Support] simulation time step
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
> > >
> > >
> > >
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