Typical Meteorological Year Data (TMY)

Source: HelioScope

Understanding Typical Meteorological Year (TMY) Data

Typical Meteorological Year (TMY) data is crucial for describing the local solar climate. It involves collecting meteorological measurements at hourly intervals over several years to create a representation of the area’s climate. The process of determining TMY data involves selecting the most representative month for each parameter.

TMY Data Calculation

The average radiation for each month is calculated over the entire measurement period. The month with the radiation closest to the monthly average across the measurement period is chosen as the TMY data for that month. This process is repeated for every month to compile a full year of hourly samples.

Interpreting TMY Data

TMY data is utilized in various meteorological applications, with only certain parameters being relevant for photovoltaic (PV) applications. Typically, time and irradiation figures are the primary focus, but advanced models may also consider temperature and wind speed.

Key Parameters in TMY Data

• Month, Day, Hour: Represent time intervals for data collection.
• Global Irradiation: Amount of energy hitting a horizontal surface during the hour.
• Direct Beam Irradiation: Irradiation perpendicular to the sun’s rays.
• Temperature and Wind Speed: Averaged values over the hour.
• Wet Bulb Temperature: Reflects humidity levels.
• Wind Direction: Indicates wind source.
• Cloud Cover: Estimation of sky coverage by clouds.

Additional Considerations for PV Applications

In PV applications, diffuse radiation plays a significant role. It can be calculated from global irradiation, direct beam tracking radiation, and the sun’s elevation angle. Models like the Perez model help in predicting the distribution of diffuse radiation across the sky accurately.

Understanding TMY data and its parameters is essential for optimizing solar energy systems and assessing their performance in specific climatic conditions.

Source: Forums – Forum Valentin Software

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