""" irradiance.py from pvlib ======================== Extremely stripped down, reimplementation/vendorized version from: https://github.com/pvlib/pvlib-python/ The rational for not including this library as a strict dependency is to avoid including a dependency on pandas, keeping load time low, and PyPy compatibility Most of the functions will import pvlib and use it for calculations, except for one case which allows this to be used without `pvlib` For a full list of contributors to this file, see the `pvlib` repository. The copyright notice (BSD-3 clause) is as follows: BSD 3-Clause License Copyright (c) 2013-2018, Sandia National Laboratories and pvlib python Development Team All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. Neither the name of the {organization} nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. """ from math import acos, cos, degrees, exp, isnan, radians, sin nan = float("nan") def aoi_projection(surface_tilt, surface_azimuth, solar_zenith, solar_azimuth): projection = ( cos(radians(surface_tilt)) * cos(radians(solar_zenith)) + sin(radians(surface_tilt)) * sin(radians(solar_zenith)) * cos(radians(solar_azimuth - surface_azimuth))) return projection def aoi(surface_tilt, surface_azimuth, solar_zenith, solar_azimuth): projection = aoi_projection(surface_tilt, surface_azimuth, solar_zenith, solar_azimuth) aoi_value = degrees(acos(projection)) return aoi_value def poa_components(aoi, dni, poa_sky_diffuse, poa_ground_diffuse): poa_direct = max(dni * cos(radians(aoi)), 0.0) if poa_sky_diffuse is not None: poa_diffuse = poa_sky_diffuse + poa_ground_diffuse else: poa_diffuse = poa_ground_diffuse poa_global = poa_direct + poa_diffuse irrads = {} irrads['poa_global'] = poa_global irrads['poa_direct'] = poa_direct irrads['poa_diffuse'] = poa_diffuse irrads['poa_sky_diffuse'] = poa_sky_diffuse irrads['poa_ground_diffuse'] = poa_ground_diffuse return irrads def get_ground_diffuse(surface_tilt, ghi, albedo=.25, surface_type=None): diffuse_irrad = ghi*albedo*(1.0 - cos(radians(surface_tilt)))*0.5 return diffuse_irrad def get_sky_diffuse(surface_tilt, surface_azimuth, solar_zenith, solar_azimuth, dni, ghi, dhi, dni_extra=None, airmass=None, model='isotropic', model_perez='allsitescomposite1990'): if model == 'isotropic': return isotropic(surface_tilt, dhi) else: from pvlib import get_sky_diffuse return get_sky_diffuse(surface_tilt, surface_azimuth, solar_zenith, solar_azimuth, dni, ghi, dhi, dni_extra=dni_extra, airmass=airmass, model=model, model_perez=model_perez) def get_absolute_airmass(airmass_relative, pressure=101325.): airmass_absolute = airmass_relative*pressure/101325. return airmass_absolute def get_relative_airmass(zenith, model='kastenyoung1989'): z = zenith zenith_rad = radians(z) if 'kastenyoung1989' == model: try: am = (1.0 / (cos(zenith_rad) + 0.50572*((6.07995 + (90.0 - z))**-1.6364))) except: am = nan if isinstance(am, complex): am = nan else: raise ValueError('%s is not a valid model for relativeairmass', model) return am def get_total_irradiance(surface_tilt, surface_azimuth, solar_zenith, solar_azimuth, dni, ghi, dhi, dni_extra=None, airmass=None, albedo=.25, surface_type=None, model='isotropic', model_perez='allsitescomposite1990', **kwargs): poa_sky_diffuse = get_sky_diffuse( surface_tilt, surface_azimuth, solar_zenith, solar_azimuth, dni, ghi, dhi, dni_extra=dni_extra, airmass=airmass, model=model, model_perez=model_perez) poa_ground_diffuse = get_ground_diffuse(surface_tilt, ghi, albedo, surface_type) aoi_ = aoi(surface_tilt, surface_azimuth, solar_zenith, solar_azimuth) irrads = poa_components(aoi_, dni, poa_sky_diffuse, poa_ground_diffuse) return irrads def isotropic(surface_tilt, dhi): sky_diffuse = dhi * (1 + cos(radians(surface_tilt))) * 0.5 return sky_diffuse def ineichen(apparent_zenith, airmass_absolute, linke_turbidity, altitude=0, dni_extra=1364., perez_enhancement=False): if isnan(airmass_absolute) or isnan(apparent_zenith): return {'ghi': 0.0, 'dni': 0.0, 'dhi': 0.0} # use max so that nighttime values will result in 0s instead of # negatives. propagates nans. cos_zenith = cos(radians(apparent_zenith)) if cos_zenith < 0.0: cos_zenith = 0.0 tl = linke_turbidity fh1 = exp(-altitude/8000.) fh2 = exp(-altitude/1250.) cg1 = 5.09e-5*altitude + 0.868 cg2 = 3.92e-5*altitude + 0.0387 ghi = exp(-cg2*airmass_absolute*(fh1 + fh2*(tl - 1.0))) # https://github.com/pvlib/pvlib-python/issues/435 if perez_enhancement: ghi *= exp(0.01*airmass_absolute**1.8) # use fmax to map airmass nans to 0s. multiply and divide by tl to # reinsert tl nans if ghi > 0.0: ghi = cg1 * dni_extra * cos_zenith * tl / tl * ghi else: ghi = 0.0 # BncI = "normal beam clear sky radiation" b = 0.664 + 0.163/fh1 bnci = b * exp(-0.09 * airmass_absolute * (tl - 1)) if bnci > 0.0: bnci = dni_extra * bnci else: bnci = 0.0 # "empirical correction" SE 73, 157 & SE 73, 312. try: bnci_2 = ((1.0 - (0.1 - 0.2*exp(-tl))/(0.1 + 0.882/fh1)) / cos_zenith) except: bnci_2 = 1e20 multiplier = (bnci_2 if bnci_2 > 0.0 else bnci_2) multiplier = min(multiplier, 1e+20) bnci_2 = ghi*multiplier dni = min(bnci_2, bnci) dhi = ghi - dni*cos_zenith return {'ghi': ghi, 'dni': dni, 'dhi': dhi}