A calibrated energy model requires using actual weather data for a previous year or time frame to calibrate with. Actual weather data can come in different formats and may need to be used for different weather file formats (.BIN and .EPW for example).
I think it's much more preferable to build a new weather file than to splice limited data into an existing weather file, since there would be no correspondence between the two types of data. After all, solar radiation is highly correlated to other climatic factors, so if you merge solar from one place in time to temperature, humidity, etc. for another place at a different time, I'm really not sure how much improvement you're getting, or maybe even making it worse ?
The irony of the situation is that actual historical weather data is much more plentiful than "typical year" weather data, which requires at least 8 years up to 25 years of historical data to make. For example, the NCDC maintains a running data base called the Integrated Surface Hourly (ISD) that has the weather reports for over 20,000 (8,000 usable) weather stations around the world that, for the US, lag real time by just a couple of days. Furthermore, web sources like the WeatherUnderground opens up the possibility of over 30,000 stations just in the US. The problem, of course, is that these are raw data, and needs to be processed at least twice - once to clean up the data and add the solar radiation - and then again to convert to formats recognizable by simulation programs.
There is a new, free, open-source tool to navigate, create, and visualize data from various weather files:
There are some really great sites that you can purchase files. Some sites include pre-formated files for .epw, .bin, etc.
The cost ranges from about 15-75 dollars for a year of data. These include typical meteorological years, actual meteorological years, etc.
In my opinion it is totally worth it to just purchase the file. Sometimes when you download free data (from say NCDC or energyplus real-time data, which I think is the same source), there can be gaps, errors, missing data, etc. which can take hours to clean up. I just downloaded a file for 2013 in downtown los angeles and for 40 dollars and was able to get the following file formats (AMY.bin, AMY.txt/.csv, AMY.epw, AMY.stat, AMY.tm2, AMY.tm3). It took about 1 hour from the time I purchased to get the file. TOTALLY WORTH IT. I won't post the names for the sites, but do a keyword search and you should be able to find something fairly quick.
Good answer but can you add the url's fo the sites where you can purchase files, etc?
EnergyPlus comes with a free weather file editing tool called "Weather Statistics and Conversions". What I usually do is convert a weather file from the closest weather station from .epw to .csv. I then take the actual weather data I have and replace it in the .csv file. Normally I only have DB, WB, Dew Point, Humidity Ratio. I then use the same tool to convert the .csv file back to .epw or .bin for use in energy analysis programs. The only issue with this method is that the solar data comes from the original weather file and it is not the actual solar data.
Asked: 2014-09-01 22:17:04 -0600
Seen: 7,260 times
Last updated: Sep 15 '15
By "previous year", do you mean the time frame of calibration? Perhaps elaborate this example a bit more too.
Thanks for the comment. That also reminded me that the calibration time frame won't always be one calendar year, it could be parts of two different calendar years (Oct. 2013 - Sep. 2014 for example).