How is climate data selected and formatted for simulation?
For the purposes of building energy modeling, climate data is usually converted into one-year dataset that represents typical conditions at hourly increments.
Typical Meteorological Year (TMY2) Weather Data
The Typical Meteorological Year format (TMY) is one common methodology for creating this dataset, and was originally developed for solar energy system simulations. TMY data is not truly averaged climate data. Rather, it is 12 individual months of selected observational data that is concatenated to form a complete year. This data accounts for peaks and swings typical of the climate. This is important for energy analysis because it's those peaks and swings that often take the most energy to deal with. The data is selected so that it presents the range of weather conditions for the location, which are consistent with the long-term averages for the location.
TMY2 weather data sets are a collation of selected weather data for a specific location, generated from the 1961-1990 National Solar Radiation Data Base.
California Title 24 Weather Data (CTZ2)
This weather data covers the 16 California climate zones. The original source data is available from the California Energy Commission.
Autodesk Climate Server Weather Data
GBS has 1.3 million weather station locations worldwide at a spatial resolution of approximately 20 km. For some locations ASHRAE climate zone assignments using GBS weather may differ from ASHRAE Climate Zone assignments usingTMY2 weather because the weather data used by GBS represents observed and/or derived data from one calendar year while TMY2 weather data, used by most energy analyses, is a compiled dataset of weather spanning thirty years.
3TIER Weather Data
3TIER® is a third party provider of weather data. 3TIER's weather data incorporates worldwide reanalysis data with mesoscale numerical weather prediction (NWP) models. NWP models can simulate past periods of time to create a complete climatology for a location. GBS’s use of historical weather data allows users to simulate the performance of existing buildings and calibrate the model of that building. This can be accomplished by using past utility billing records that correspond to the weather data period of time. Once calibrated, GBS tools enable users to simulate energy efficiency alternatives and use the results to inform energy-efficient upgrade decisions.
What file format is the data available in?
Most weather data from Autodesk Green Building Studio can be downloaded as comma separated values (.csv) or DOE-2 binary files (.bin).
Other programs use other file formats. For example, the Energy Plus engine uses .epw files and the Ecotect Weather Tool uses .wea files. The data can often be converted.
What weather variables are included in GBS's data?
The data includes the following fields, for each hour of the year:
Whether the data is for the climate or weather data for a specific year, files store the data in a similar format using these fields. See the Autodesk Sustainability Workshop for more detail on climate variables and how they impact high-performance design.