pvdeg.degradation.arrhenius_deg#

pvdeg.degradation.arrhenius_deg(weather_df: DataFrame, meta: dict, rh_outdoor, I_chamber, rh_chamber, Ea, temp_chamber, poa=None, temp=None, p=0.5, n=1, temp_model='sapm', conf='open_rack_glass_polymer', wind_factor=0.33, model_kwarg={}, irradiance_kwarg={})[source]#

Calculate the Acceleration Factor between the rate of degradation of a modeled environment versus a modeled controlled environment. Example: If AF=25, then 1 year of Controlled Environment exposure is equal to 25 years in the field.

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

  • rh_outdoor (pd.Series) – Relative Humidity of material of interest. Acceptable relative humiditys can be calculated from these functions: - pvdeg.humidity.backsheet() - pvdeg.humidity.back_encapsulant() - pvdeg.humidity.front_encapsulant() - pvdeg.humidity.surface_relative()

  • I_chamber (float) – Irradiance of Controlled Condition [W/m²]

  • rh_chamber (float) – Relative Humidity of Controlled Condition [%]. EXAMPLE: “50 = 50% NOT .5 = 50%”

  • temp_chamber (float) – Reference temperature [°C] (“Chamber Temperature”)

  • Ea (float) – Degradation Activation Energy [kJ/mol] if Ea=0 is used there will be not dependence on temperature and degradation will proceed according to the amount of light and humidity.

  • poa (pd.DataFrame, optional) – Global Plane of Array Irradiance [W/m²]

  • temp (pd.Series, optional) – Solar module temperature or Cell temperature [°C]. If no cell temperature is given, it will be generated using the default parameters from pvdeg.temperature.cell

  • p (float) – Fit parameter When p=0 the dependence on light will be ignored and degradation will happen both day and night. As a caution or a feature, a very small value of p (e.g. p=0.0001) will provide very little degradation dependence on irradiance, but degradation will only be accounted for during daylight. i.e. averages will be computed over half of the time only.

  • n (float) – Fit parameter for relative humidity When n=0 the degradation rate will not be dependent on humidity.

  • 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:

accelerationFactor (float or pd.Series) – Degradation acceleration factor

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