DesignBuilder uses EnergyPlus format hourly weather data to define external conditions during simulations. Each location has a separate file describing the external temperature, solar radiation, atmospheric conditions etc. for every hour of the year at that location. These hourly weather data sets are often 'typical' data derived from hourly observations at a specific location by the National weather service or methodological office. Examples of these typical data include TMY2 and WYEC2 in the United States and Canada and TRY (CEC 1985) in Europe. See EnergyPlus Hourly Weather Data for more on the hourly weather data itself.
Because hourly weather data is not always available for every location, it is often necessary to use weather data for a nearby location which represents the weather of the actual site.
The DesignBuilder hourly weather data has been obtained from the Weather section of the EnergyPlus website and processed using the DesignBuilder weather data translator, but you can use any weather data provided it is in the correct format.
EnergyPlus format hourly weather data has extension 'epw' by convention.
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DesignBuilder comes with a database of hourly weather data but the EnergyPlus epw files are not loaded onto your computer until you actually need them. This keeps the size of the DesignBuilder setup program small. The first time you require an hourly weather data file it is automatically downloaded from the DesignBuilder Website into the Weather data folder on your computer where it can be accessed by EnergyPlus for any subsequent simulations. You must be connected to the Internet to download weather data in this way.
When you select an hourly weather data set on the Location tab at Site level, you do not select the file directly, but rather an hourly weather data component, which in turn references the actual file. It works this way so that we can supply you with a database of hourly weather data locations without needing to include hundreds of large hourly weather files.
When editing an hourly weather data component there are two tabs on the Hourly Weather Data dialog:
Template data can be accessed: