pvdeg.standards.eff_gap_parameters

pvdeg.standards.eff_gap_parameters(weather_df=None, meta=None, module_temp=None, weather_kwarg=None, sky_model='isotropic', temp_model='sapm', conf_0='insulated_back_glass_polymer', conf_inf='open_rack_glass_polymer', tilt=None, azimuth=None, wind_factor=0.33)

Calculate and set up data necessary to calculate the effective standoff distance for rooftop mounded PV system according to IEC TS 63126. The the temperature is modeled for T_0 and T_inf and the corresponding test module temperature must be provided in the weather data.

Parameters:

• weather_df (pd.DataFrame) – Weather data for a single location.

• meta (pd.DataFrame) – Meta data for a single location.

• measured_df (pd.DataFrame) – Measured module temperature data.

• sky_model (str, optional) – Options: ‘isotropic’, ‘klucher’, ‘haydavies’, ‘reindl’, ‘king’, ‘perez’.

• temp_model (str, optional) – Options: ‘sapm’. ‘pvsyst’ and ‘faiman’ will be added later. Performs the calculation for the cell temperature.

• conf_0 (str, optional Model for the high temperature module on the exponential decay curve.) – Default: ‘insulated_back_glass_polymer’

• conf_inf (str, optional) – Model for the lowest temperature module on the exponential decay curve. Default: ‘open_rack_glass_polymer’

• tilt (float, optional) – Tilt angle of PV system relative to horizontal. [°]

• azimuth (float, optional) – Azimuth angle of PV system relative to north. [°]

• wind_factor (float, optional) – Wind speed correction exponent to account for different wind speed measurement heights between weather database (e.g. NSRDB) and the tempeature 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.

References

R. Rabbani, M. Zeeshan, “Exploring the suitability of MERRA-2 reanalysis data for wind energy estimation, analysis of wind characteristics and energy potential assessment for selected sites in Pakistan”, Renewable Energy 154 (2020) 1240-1251.

Returns:

• T_0 (float) – An array of temperature values for a module with an insulated back or an alternatively desired small or zero standoff, [°C]. Used as the basis for the maximum achievable temperature.

• T_inf (float) – An array of temperature values for a module that is rack mounted, [°C].

• T_measured (float) – An array of values for the test module in the system, [°C] interest.

• poa (float) – An array of values for the plane of array irradiance, [W/m²]