pvdeg.standards.standoff#

pvdeg.standards.standoff(weather_df: DataFrame = None, meta: dict = None, weather_kwarg: dict = None, tilt: float | int | str = None, azimuth: float | int = None, sky_model: str = 'isotropic', temp_model: str = 'sapm', conf_0: str = 'insulated_back_glass_polymer', conf_inf: str = 'open_rack_glass_polymer', conf_0_kwarg={}, conf_inf_kwarg={}, T98: float = 70, x_0: float = 6.5, wind_factor: float = 0.33, irradiance_kwarg={}, tracker_irradiance_kwarg={}, model_kwarg={}) → DataFrame[source]#

Calculate a minimum standoff distance for roof mounded PV systems.

Will default to horizontal tilt. If the azimuth is not provided, it will use equator facing. You can use customized temperature models for the building integrated and the rack mounted configuration, but it will still assume an exponential decay.

Parameters:

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

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

  • weather_kwarg (dict) – other variables needed to access a particular weather dataset.

  • tilt (float, optional) – Tilt angle of rack mounted PV system relative to horizontal. [°] If single-axis tracker mounted, specify keyword ‘single_axis’

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

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

  • temp_model (str, optional) – Performs the calculations for the cell temperature. Options: ‘sapm_cell’,`’sapm_module’,’pvsyst_cell’,’faiman’,’faiman_rad’, `’ross’,`’noct_sam’, `’fuentes’, ‘generic_linear’. Note: we cannot simply drop in pvsyst using conf_0=insulated and conf_inf=freestanding. This will yield erroneous results as these configurtions represent different cases. Must provide equivalent conf_0_kwarg and conf_inf_kwarg between temperature models.

  • 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’

  • conf_0_kwarg (dict, optional) – keyword arguments for the high tempeature module on the exponential decay curve. Use for temperature models other than sapm model arguments representing an ‘insulated_back_glass_polymer’ module.

  • conf_inf_kwarg (dict, optional) – keyword arguments for the lowest tempeature module on the exponential decay curve. Use for temperature models other than sapm model arguments representing an ‘open_rack_glass_polymer’ module.

  • x_0 (float, optional) – Thermal decay constant (cm), [Kempe, PVSC Proceedings 2023]

  • 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 10m 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 caluation. options: sol_position, tilt, azimuth, sky_model. See pvdeg.spectral.poa_irradiance. Used in place of dedicated arguments in the case of a top down scenario method call.

  • model_kwarg (dict, optional) – dictionary to provide to the temperature model, see temperature.temperature for more information

  • Rabbani (R.)

  • Zeeshan (M.)

  • for ("Exploring the suitability of MERRA-2 reanalysis data)

  • estimation (wind energy)

  • potential (analysis of wind characteristics and energy)

  • Pakistan" (assessment for selected sites in)

  • 1240-1251. (Renewable Energy 154 (2020))

Returns:

  • x (float [cm]) – Minimum installation distance in centimeter per IEC TS 63126 when the default settings are used. Effective gap “x” for the lower limit for Level 1 or Level 0 modules (IEC TS 63216)

  • T98_0 (float [°C]) – This is the 98ᵗʰ percential temperature of a theoretical module with no standoff.

  • T98_inf (float [°C]) – This is the 98ᵗʰ percential temperature of a theoretical rack mounted module.

References

M. Kempe, et al. Close Roof Mounted System Temperature Estimation for Compliance to IEC TS 63126, PVSC Proceedings 2023

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