Hi there
Have anyone experience in creating a new weather file from wunderground
data?
This is my case: I use the Caracas file download from the EnergyPlus
site converted to eQuest format but I live in other hotter city, Puerto
Ordaz that has a wunderground station working since last april.
Thank you very much!
Khristiam Alvarez
Hi Khristiam,
Once you have collected data from wunderground, you can create a custom weather file to run in EnergyPlus using the WeatherConverter executable (Weather.exe), which comes with the EnergyPlus download. To do so, enter your weather data into an excel spreadsheet and create a definition file using a text editor. The definition file defines the columns in your spreadsheet, the associated units, time steps, etc, and must end in ".def". The Weather.exe interface reads the .def file and converts the excel sheet into an epw file. The executable will also create a .csv, .ddy (design day), and .stat file for you. You can create the weather file with any time step you'd like (1 min, 5 min, 1 hour...).
The EnergyPlus AuxilaryPrograms document provides more detail on this process and shows some examples.
Are you running in eQuest of EnergyPlus? Unfortunately I'm not familiar with the eQuest weather file format or how to convert E+ weather files to eQuest weather files, but maybe the csv output could help.
Regards,
Lesley Herrmann
Dear Jim and Lesley
Thank you very much for your emails.
I will implement what you reccomend.
I use eQuest software made by DOE, which require *.bin files for weather
data.
I used a file conversion software to convert *.epw to *.bin
Now, do I have to wait until april 2013 to get a full one year data from
wunderground for the software to work? or can I use existing data?
Regards
Khristiam Alvarez
Khristiam,
I guess it depends on how soon you need to run your model. You can create a sub-yearly weather file (say, April 2012 - August 2012), but WeatherConverter will not interpolate or perform any kind of averaging techniques to complete the year. You can run an EnergyPlus model with your sub-yearly weather file as long as you set the run period equal to the length of your weather file, or to a time period within your weather file, (say, the month of June for the example above). I would think you could do the same in eQuest.
Hope this helps.
Lesley
There is a problem with using weather underground weather data for
simulation. All of the .bin or .epw weather data are Typical meteorological
(TMY) year is averaged over time- so using them to predict the average year
thermal energy use works reasonably well. Data from weather underground is
actual meteorological year (AMY) this will produce a model of the year that
the weather data was measured. The only time when AMY weather data should
be used for modeling is when calibrating a model for an existing building.
The calibration process is to use actual weather data to remove one
variable and then to modify the model to align the loads and consumption to
the designed and measured data from the building. Once the model has
been calibrated with actual weather data, then the modeler changes back
to typical weather data for predicting the average year. Never should one
attempt to predict an typical year from actual year weather data. If you do
not feel that the closest typical weather data to your location is
sufficient than you should pay for a file to be created from
http://weatheranalytics.com/
Best regards
Well said, I agree, custom weather files should be used for calibration purposes. I would also recommend weatheranalytics.com.
One other thought, Khristiam: If you are creating a custom weather file for calibration, wunderground does not provide your solar data. Unless you have another source for this component, weatheranalytics might be your best option.
Lesley
I have attempted to create a simulation-usable weather file from the raw data from
WUnderground, using the procedure that I have developed over the past 15 years working
with other sources of raw data, especially NCDC's Integrated Surface Hourly (ISH) data base.
The main problems I've encountered, besides learning how to download conveniently the raw
data for multiple year, is the absence of sky cover information that I need to extrapolate
the solar radiation using several empirical models. I have not pursued this track, i.e.,
using WUnderground raw data, very much because I'm all set up to process ISH data, which
are records from 8,000 official meteorological stations around the world, which have met
my needs in almost all cases. For example, for locations around Caracas, the ISH also
contains good data for Valencia, as well as Maracay-Ba-Sucr and Pto-Cabello.
Joe Huang
Thank you guys.
I have read with much care and interest all the information you've
kindly sent and am sure my modelling efforts will be better from now on.
Warmest Regards
Khristiam Alvarez
Dear Khristiam,
I have been using .epw files from www.weatheranalytics.com in the last couple of years, and recommend that you look at their site because their files are more complete than what you might put together from www.wunderground.com. (and inexpensive, too!)
However, I made a another method to collect data from Wunderground before Weather Analytics was founded, and I have attached the executable file as well as the source code. Warning! I have not used this for a couple of years and am not sure if it still works properly.
Finally, someone posted an Excel file on this forum or the EnergyPlus forum with a macro to pull information from Wunderground - I have included that, too.
James V Dirkes II, PE, BEMP, LEED AP
Dear Khristiam,
We use Meteonorm software when we need a weather file for a city that is not in the Energy Plus database. It uses a large weather station database and where there aren't weather stations, the software interpolates data between different stations. The software isn't free though, it's about 500 euros.
http://meteonorm.com/
Another source I've used that is free or cheap depending on the type of weather data you require is the NOAA site. It looks like their 2 nearest weather stations are called Ciudad Bolivar (Lat: 8.15 deg., Long: -63.550 deg.) and General Manuel Carl (lat: 8.283 deg, long: -62.75 deg.) Here is their site: http://www.ncdc.noaa.gov/cdo-web/#t=firstTabLink. You can search for the stations on the map and get hourly data text files. Usually I take these and convert them to .wea or .epa files through Weather Tool (this is an Autodesk product). You might also be able to use the Energy Plus Weather File Convertor which is free, but I haven't used it to convert text files to weather files before.
Krista Raines, LEED AP BD+C
Since this thread is still bouncing around BLDG-SIM, I thought I'd update others on what I
have done using the ISH data base and sent to Khristiam.
As Krista mentions, the ISH contains two locations : Ciudad Bolivar (WMO 804440) and
General Manuel Carl (WMO 804463). Unfortunately, the second station contains only wind
data and no temperatures, except for half a year in 2011.
The first station, however, contains fairly complete data (~4000 records /year for 2010),
so I processed that to create a usable weather file in the DOE-2 *.BINM format needed for
eQUEST (my procedure also produces other formats such as TMY3, TMY2, and EPW). However,
when Khristiam used the file, it produced significantly lower cooling loads than using
Caracas, which of course doesn't make too much sense. So, I investigated and found that
the weather file I produced contained very low dew point temperatures around 0 C during
many of the nighttime hours. I traced this to the raw ISH data where the station
(airport) had entered +0000 dew point temperatures over 400 times instead of +9999 for
missing data. So, I edited the raw data file and created a corrected weather file, and
made a mental note to modify my procedure to check for such occurences.
Joe Huang