Dear bldg-sim'rs,
I usually take this kind of data for granted (our industry has been
commoditized so much!).
Statistics not being my strong point, does anybody know of any good web
resources for working out percentile data of various weather
characteristics? I have hourly data available and would like to
undertake the task in excel (or openoffice).
Thanks
Chris Yates
Can't you just sort the data and then look at the values corresponding
to the percentiles of interest, i.e.,
8322 for 95% percentile of 8760 hourly data? Am I missing something
here ? The only wrinkle in respect to wind speeds is that the hourly
values are spot measurements, and not time-averaged over the hour.
Joe Huang
Dear All,
Thank you very much. This is all useful stuff. I guess binning isn't in
the engineering culture over here in the UK in the same way it is in the
UK. We tend merely to use hourly weather data to do simulations and can
take design data from CIBSE (most of the time).
I'll definitely undertake these exercises. In the mean time, I wrote
some very crude vba to step through the weather data and calculate its
effect on battery charge which I'll be happy to share once I've tidied
it up a bit.
Cheers
Chris Yates
Thanks Dru,
It's actually minimum wind speed occurrences that I'm interested in -
when we aren't generating from the wind turbine. Perhaps the best
solution is just get to grips with the E+ WTG model and use hourly data.
Best
Chris Yates
Each of the EPW files have a "stat" file.
But you might investigate the "DView" software.
I'm not quite sure what you're after -- detailed analysis
(spreadsheetable) or just viewable.
We're doing an off grid system on a farm house in Cumbria, North
England. If anybody has ever seen the film Withnail & I, it's just down
the road from where the famous country retreat was filmed.
I'm trying to work out how often there's a need for the backup generator
to kick in. I've done a crude exercise based on hourly data using vba
which will suffice for now. It doesn't take into account rate at which
batteries can be re-charged (yet), but it does allow for quite a big
margin (70%) by assuming everything does a round trip through the
batteries when they're not fully charged, plus the Depth of Discharge is
relatively modest at 20%.
Talking to one supplier, the frequency of the generator kicking in
sounds like a moot point - they're plc logic brings in the generator on
a fairly regular basis to condition the batteries.
Cheers
Chris Yates