.IDEAS.BoundaryConditions.WeatherData.UsersGuide

Information

This package contains models to read weather data. The weather data format is the Typical Meteorological Year (TMY3) as obtained from the EnergyPlus web site at http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data.cfm.

Adding new weather data

To add new weather data, proceed as follows:

1. Download the weather data file with the epw extension from http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data.cfm.
2. Add the file to Buildings/Resources/weatherdata (or to any directory for which you have write permission).
3. On a console window, type

     cd Buildings/Resources/weatherdata
     java -jar ../bin/ConvertWeatherData.jar inputFile.epw
   

   This will generate the weather data file inputFile.mos, which can be read by the model Buildings.BoundaryConditions.WeatherData.ReaderTMY3.

Implementation

The TMY3 weather data, as well as the EnergyPlus weather data, start at 1:00 AM on January 1, and provide hourly data until midnight on December 31. Thus, the first entry for temperatures, humidity, wind speed etc. are values at 1:00 AM and not at midnight. Furthermore, the TMY3 weather data files can have values at midnight of December 31 that may be significantly different from the values at 1:00 AM on January 1. Since annual simulations require weather data that start at 0:00 on January 1, data need to be provided for this hour. Due to the possibly large change in weatherdata between 1:00 AM on January 1 and midnight at December 31, the weather data files in the Buildings library do not use the data entry from midnight at December 31 as the value for t=0. Rather, the value from 1:00 AM on January 1 is duplicated and used for 0:00 on January 1. To maintain a data record with 8760 hours, the weather data record from midnight at December 31 is deleted. These changes in the weather data file are done in the Java program that converts EnergyPlus weather data file to Modelica weather data files, and which is described below.