pvdeg.degradation.IwaVantHoff#

pvdeg.degradation.IwaVantHoff(weather_df, meta, poa=None, temp=None, Teq=None, p=0.5, Tf=1.41, temp_model='sapm', conf='open_rack_glass_polymer', wind_factor=0.33, model_kwarg={}, irradiance_kwarg={})[source]#

Calculate IWa: Environment Characterization [W/m²]. For one year of degradation, the controlled environment lamp settings will need to be set to IWa.

Parameters:

  • weather_df (pd.DataFrame) – DataFrame containing at least dni, dhi, ghi, temperature, wind_speed

  • meta (dict) – Location meta-data containing at least latitude, longitude, altitude

  • poa (pd.Series or pd.DataFrame, optional) – Series or DataFrame containing ‘poa_global’, Global Plane of Array Irradiance [W/m²]

  • temp (pd.Series, optional) – Solar module temperature or Cell temperature [°C]

  • Teq (pd.Series, optional) – VantHoff equivalent temperature [°C]

  • p (float) – Fit parameter

  • Tf (float) – Multiplier for the increase in degradation for every 10[°C] temperature increase

  • temp_model ((str, optional)) – Specify which temperature model from pvlib to use. Current options:

  • conf ((str)) –

    The configuration of the PV module architecture and mounting configuration. Currently only used for ‘sapm’ and ‘pvsys’. With different options for each.

    ’sapm’ options: open_rack_glass_polymer (default), open_rack_glass_glass, close_mount_glass_glass, insulated_back_glass_polymer

    ’pvsys’ options: freestanding, insulated

  • wind_factor (float, optional) – Wind speed correction exponent to account for different wind speed measurement heights between weather database (e.g. NSRDB) and the temperature model (e.g. SAPM) The NSRDB provides calculations at 2 m (i.e module height) but SAPM uses a 10 m height. It is recommended that a power-law relationship between height and wind speed of 0.33 be used*. This results in a wind speed that is 1.7 times higher. It is acknowledged that this can vary significantly.

  • irradiance_kwarg ((dict, optional)) – keyword argument dictionary used for the poa irradiance calculation. options: sol_position, tilt, azimuth, sky_model. See pvdeg.spectral.poa_irradiance.

  • model_kwarg ((dict, optional)) – keyword argument dictionary used for the pvlib temperature model calculation. See https://pvlib-python.readthedocs.io/en/stable/reference/pv_modeling/temperature.html # noqa for more.

Returns:

Iwa (float) – Environment Characterization [W/m²]

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