SolarUtils is set of Python wrappers around the publicly available NREL SOLPOS and SPECTRL2 C-language computer programs that calculate solar position and spectral decomposition. Please read the NREL disclaimer and license. Usage of this software implies acceptance of the terms.

Use pip to install SolarUtils from the PyPI:

pip install SolarUtils

You can also download a source distribution from PyPI or clone the repository and use Python distutils:

python setup.py install

SolarUtils has no requirements for usage however for installation, testing and to build the documentaiton you will need the following pacakges:

• NumPy
• PyTest
• Sphinx

See SOLPOS Documentation and SPECTRL2 Documentation for more detail.

>>> from solar_utils import *
>>> import pandas as pd
>>> location = [35.56836, -119.2022, -8.0]
>>> datetime = [2013, 6, 5, 12, 31, 0]
>>> weather = [1015.62055, 40.0]
>>> (angles, airmass) = solposAM(location, datetime, weather)
>>> zenith, azimuth = angles
>>> zenith
15.074043273925781
>>> azimuth
213.29042053222656]
>>> am, amp = airmass
>>> am
1.0352272987365723
>>> amp
1.0379053354263306]

>>> units = 1
>>> location = [33.65, -84.43, -5.0]
>>> datetime = [1999, 7, 22, 9, 45, 37]
>>> weather = [1006.0, 27.0]
>>> orientation = [33.65, 135.0]
>>> atmospheric_conditions = [1.14, 0.65, -1.0, 0.2, 1.36]
>>> albedo = [0.3, 0.7, 0.8, 1.3, 2.5, 4.0] + ([0.2] * 6)
>>> specdif, specdir, specetr, specglo, specx = spectrl2(
...     units, location, datetime, weather, orientation,
...     atmospheric_conditions, albedo
... )
>>> spec = pd.DataFrame(
...     {'DIF': specdif, 'DIR': specdir, 'ETR': specetr, 'GLO': specglo},
...     index=specx
... )
>>> f = spec.plot()
>>> f.set_title('Solar Spectrum Example')
>>> f.set_xlabel('Wavelength, $\lambda [\mu m]$')
>>> f.set_ylabel('Spectral Irradiance, $I_{\lambda} [W/m^2/\mu m]$')
>>> f.grid(True)
>>> f.figure.show()