[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[EnergyPlus_Support] Re: A question about using real-time weather data to do a simulation
Joe,
Thank you very much for your detailed explain about the historical weather data, it helps me a lot to understand it.
Ke
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Joe Huang <YJHuang@...> wrote:
>
> Sorry, had the wrong link address for the map on my Web site on the previous post. This
> one is correct.
>
> Joe
>
> Joe Huang
> White Box Technologies, Inc.
> 346 Rheem Blvd., Suite 108D
> Moraga CA 94556
> yjhuang@...
> www.whiteboxtechnologies.com
> (o) (925)388-0265
> (c) (510)928-2683
> "building energy simulations at your fingertips"
>
>
> On 4/10/2012 1:43 PM, Joe Huang wrote:
> > Ke, others,
> >
> > Historical weather data are now increasingly available on the Web. The National
> > Climatic Data
> > Center, which is the archival arm of the National Weather Service, two months ago
> > changed their policy
> > to make the ISH (Integrated Surface Hourly) data base going back to 1980 for
> > 6,000-16,000 stations
> > around the world publicly accessible to anyone on the Web
> > (See http://www.ncdc.noaa.gov/oa/climate/isd/index.php for data access, info, etc.)
> >
> > The ISH is the original source for NREL's Real-Time Weather Data, the TMY3 weather
> > files, as well as
> > ASHRAE's IWEC2 weather files for 3,012 international locations for which I was the
> > contractor. From my review,
> > the ISH contains close to 7,000 stations worldwide (2,000 in the US, 600+ in Canada) of
> > sufficient
> > quality to produce hourly weather files.
> >
> > (seethe map on my web site http://www.whiteboxtechnologies.com/WB-weather/google-select.php
> > for the stations for which I've already produced weather files for 2010).
> >
> > Another source for historical weather data is the Weather Underground
> > (www.wunderground.com).
> > I'm impressed by the sheer number of stations available, which must be upwards of
> > 10,000 for the US alone.
> >
> > The biggest problem with all these weather data is, of course, the absence of solar
> > radiation data.
> > It's just a fact of life that, outside of a very few number of research stations, solar
> > radiation is not
> > recorded. A major, perhaps the major, task in the creation of "typical year" weather files
> > like the TMY, TMY2, IWEC, IWEC2, etc., is to derive the solar radiation (total global
> > and direct normal)
> > utilizing other climatic indicators, esp. cloud cover, temperature rise, etc. There have
> > been dozens
> > of models and techniques developed around the world, e.g., NREL uses the Metstat Model, IWEC
> > used the Kasten Model, and I combined several models (Zhang-Huang, Gompertz, ASHRAE Clear
> > Sky) for the IWEC2. The bottom line is that you can expect to get within 5-10% on the
> > yearly totals
> > (especially if there's measured data to calibrate the models), but don't expect great
> > agreement on an hourly basis.
> >
> > In the last few years, another avenue has opened with deriving solar radiation from
> > satellite observations.
> > For US locations, Clean Power Research has a Web site (
> > www.solaranywhere.com/Public/SelectData.aspx )
> > that allows you to download hourly solar data for free on a 10 km grid from 1998 through
> > 2009, but data for later
> > years requires a hefty license fee. I did a study in June 2011 comparing
> > satellite-derived solar to high-quality
> > ground measurements and found them to be very close, particularly at the daily level.
> >
> > So, the data are all out there, but putting them together would take some time and
> > effort, especially if
> > you haven't dealt with this before. Another option is to get in touch with me, since
> > over the past five
> > years I've built up all the software and techniques that I could create either a
> > historical year weather file
> > from the ISH in almost no time at all, and at a cost much lower than the time you would
> > have spent in
> > working this out.
> >
> > Joe
> >
> > Joe Huang
> > White Box Technologies, Inc.
> > 346 Rheem Blvd., Suite 108D
> > Moraga CA 94556
> > yjhuang@...
> > www.whiteboxtechnologies.com
> > (o) (925)388-0265
> > (c) (510)928-2683
> > "building energy simulations at your fingertips"
> >
> > On 4/10/2012 11:48 AM, Ke Xu wrote:
> >>
> >> Linda,
> >> I recalled this question today, and looked into the E+ AuxiliaryPrograms document, it
> >> is stated that
> >> "Real-Time weather data is available from the EnergyPlus web site. From the web site:
> >> "Hourly weather data from stations across the world is continuously collected and
> >> stored into
> >> a local database. The data is available through this web interface. Most stations have
> >> information for dry bulb temperature, wet bulb temperature, wind speed/direction,
> >> atmospheric pressure, visibility, cloud conditions, and precipitation type. Data may not be
> >> available for all stations and may not be contiguous for time period selected." The data is
> >> available in two output formats: CSV and IWEC. Note that their CSV is not the same as
> >> EnergyPlus CSV format. If you wish to get weather data from the real time sources, it
> >> may be
> >> easier to use the IWEC format with the EnergyPlus WeatherConverter program; HOWEVER,
> >> they do not collect solar data and, currently, the WeatherConverter cannot generate solar
> >> data for these data files."
> >> And I also checked the document "Real-Time Weather Data Access Guide" downloaded from
> >> http://apps1.eere.energy.gov/buildings/energyplus/pdfs/weatherdata_guide_34303.pdf
> >> It indicated that the IWEC format file contains the following variables:
> >> Entry Units/Notes
> >> Local Date and Time YYYYMMDDHH
> >> Dry Bulb Temperature Tenths of Degree Celsius
> >> Dew Point Temperature Tenths of Degree Celsius
> >> Wind Direction Degrees (0º = North)
> >> Wind Speed Tenths of Meter Per Second
> >> Altimeter Hundreds of Pascals
> >> Visibility Tenths of Kilometers
> >>
> >> Therefore, I think that the original data sets-either .IWC or .CSV doesn't contain
> >> solar radiation as a variable, is WeatherConverter adding the solar information somehow
> >> during the translation?
> >>
> >> Thanks.
> >>
> >> Ke
> >>
> >> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> >> <mailto:EnergyPlus_Support%40yahoogroups.com>, Linda Lawrie <linda@> wrote:
> >> >
> >> > I believe the real time weather site includes "global horizontal"
> >> > solar. If you put that through the EnergyPlus Weather Converter it
> >> > will use an algorithm to split the global into direct and diffuse
> >> > that EnergyPlus needs.
> >> >
> >> > At 08:04 PM 9/25/2011, Ke Xu wrote:
> >> > >Hello,everyone,
> >> > >
> >> > >To my understanding, the real-time weather file only includes
> >> > >outside air dry bulb temp, dew point temp, wind direction and speed,
> >> > >etc., but there is no solar radiation information. My question is,
> >> > >without the solar radiation information, how does E+ calculate the
> >> > >hourly cooling load and if it is necessary to incorporate the solar
> >> > >radiation data, is there any public resources that I can reach? and
> >> > >how can I incorporate that into EPW file?
> >> >
> >>
> >>
>
------------------------------------
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
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 currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/EnergyPlus_Support/join
(Yahoo! ID required)
<*> To change settings via email:
EnergyPlus_Support-digest@xxxxxxxxxxxxxxx
EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx
<*> To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/