pvlib.solarposition.nrel_earthsun_distance¶
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pvlib.solarposition.
nrel_earthsun_distance
(time, how='numpy', delta_t=67.0, numthreads=4)[source]¶ Calculates the distance from the earth to the sun using the NREL SPA algorithm described in [1].
Parameters: - time : pd.DatetimeIndex
- how : str, optional, default ‘numpy’
Options are ‘numpy’ or ‘numba’. If numba >= 0.17.0 is installed, how=’numba’ will compile the spa functions to machine code and run them multithreaded.
- delta_t : float, optional, default 67.0
If delta_t is None, uses spa.calculate_deltat using time.year and time.month from pandas.DatetimeIndex. For most simulations specifing delta_t is sufficient. Difference between terrestrial time and UT1. Note: delta_t = None will break code using nrel_numba, this will be fixed in a future version. By default, use USNO historical data and predictions
- numthreads : int, optional, default 4
Number of threads to use if how == ‘numba’.
Returns: - dist : pd.Series
Earth-sun distance in AU.
References
[1] (1, 2) Reda, I., Andreas, A., 2003. Solar position algorithm for solar radiation applications. Technical report: NREL/TP-560- 34302. Golden, USA, http://www.nrel.gov.