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pvdeg.standards.standoff#

pvdeg.standards.standoff(weather_df=None, meta=None, weather_kwarg=None, tilt=0, azimuth=None, sky_model='isotropic', temp_model='sapm', conf_0='insulated_back_glass_polymer', conf_inf='open_rack_glass_polymer', T98=70, x_0=6.5, wind_factor=0.33)[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.

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

  • 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) – Options: ‘sapm’. ‘pvsyst’ and ‘faiman’ will be added later. Performs the calculations 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’

  • 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 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.

  • Rabbani (R.) – estimation, analysis of wind characteristics and energy potential assessment for selected sites in Pakistan”, Renewable Energy 154 (2020) 1240-1251.

  • Zeeshan (M.) – estimation, analysis of wind characteristics and energy potential assessment for selected sites in Pakistan”, Renewable Energy 154 (2020) 1240-1251.

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

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.

  • T98 (float [°C]) – This is the 98ᵗʰ percential temperature that was calculated to.

References

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

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