Meteo Database > TMY data generation

This tool provides a simple to use method to generate Typical Meteorological Years based on time series of hourly data for at least 10 years.

See the glossary for the definition of TMY, or the subtopic TMY generation algorithm for the detailed methods used in this tool.

The dialog is only available if you have sufficient data to process a TMY as described in the conditions from "Site and meteo files" below.

Site and meteo files

The first choice of this dialog is the site. Sites present in this list are restricted to meet a certain set of conditions:

•Each .MET must be for the same place (name and location of the site), must be from the same source and for separate years (e.g. you can't make a TMY from two separate sources, or from having duplicate of a single year).

•Each .MET file separately must be valid to use in a simulation and contain a full year of data from 1st of January to 31 of December.

•A minimum of 10 years of consecutive data.

•In order for PVsyst to recognize the number of year, the year label should appear at the end of the file name, i:e: "Meteo_Custom_Imported_20XX.MET".

If more than 10 years of data from .MET files is available, the tool lets you select which consecutive years .MET files to include in the generation.

Generation parameters

The tool gives you the option of which method to use:

•The method based on the ISO norm 15927-4_2005(en)

•The method based on the Sandia approach, applied for the NREL NSRDB TMY2 dataset

•The method used by the NREL NSRDB for TMY (previously used for the TMY3 dataset, which is an update of the Sandia approach), TMY files from the NSRDB website might differ from TMY generated with this tool

oVariants of the NSRDB TMY for generating TGY (Typical Global horizontal irradiance Year) and TDY (Typical Direct normal irradiance Year)

•Custom TMY with user defined weights and additional options

Table and graph

The tool displays two tables:

•The long-term monthly averages based on the meteo files selected.

•The monthly values of the TMY generated based on the files selected.

The tool displays a graphic with various options:

•Comparison of the monthly values of the TMY to the long-term monthly averages

•Comparison of the long-term cumulative distribution function to the selected month cumulative distribution function for the variables defined in the method selected previously (see TMY generation algorithm).