def test_perez_diffuse_luminance(df_perez_luminance):
"""
Test that the calculation of luminance -- first step in using the vf model
with Perez -- is functional
"""
df_inputs = df_perez_luminance[[
'surface_tilt', 'surface_azimuth', 'solar_zenith', 'solar_azimuth',
'dni', 'dhi'
]]
(timestamps, surface_tilt, surface_azimuth, solar_zenith, solar_azimuth,
dni, dhi) = breakup_df_inputs(df_inputs)
df_outputs = perez_diffuse_luminance(timestamps, surface_tilt,
surface_azimuth, solar_zenith,
solar_azimuth, dni, dhi)
col_order = df_outputs.columns
tol = 1e-8
np.testing.assert_allclose(df_outputs.values,
df_perez_luminance[col_order].values,
atol=0,
rtol=tol)
def _calculate_luminance_poa_components(timestamps, DNI, DHI, solar_zenith,
solar_azimuth, surface_tilt,
surface_azimuth):
"""Calculate Perez-like luminance and plane-of-array irradiance values.
Parameters
----------
timestamps : array-like
List of timestamps of the simulation.
DNI : array-like
Direct normal irradiance values [W/m2]
DHI : array-like
Diffuse horizontal irradiance values [W/m2]
solar_zenith : array-like
Solar zenith angles [deg]
solar_azimuth : array-like
Solar azimuth angles [deg]
surface_tilt : array-like
Surface tilt angles, from 0 to 180 [deg]
surface_azimuth : array-like
Surface azimuth angles [deg]
Returns
-------
luminance_isotropic : numpy array
Luminance values of the isotropic sky dome area
luminance_circumsolar : numpy array
Luminance values of the circumsolar area
poa_horizon : numpy array
Plane-of-array irradiance coming from horizon band and incident on
the sides of the PV rows [W/m2]
poa_circumsolar_front : numpy array
Plane-of-array irradiance coming from the circumsolar area and
incident on the front side of the PV rows [W/m2]
poa_circumsolar_back : numpy array
Plane-of-array irradiance coming from the circumsolar area and
incident on the back side of the PV rows [W/m2]
aoi_front_pvrow : numpy array
Angle of incidence of direct light on front side of PV rows [deg]
aoi_back_pvrow : numpy array
Angle of incidence of direct light on back side of PV rows [deg]
"""
# Calculations from utils function
df_inputs = perez_diffuse_luminance(timestamps, surface_tilt,
surface_azimuth, solar_zenith,
solar_azimuth, DNI, DHI)
luminance_isotropic = df_inputs.luminance_isotropic.values
luminance_circumsolar = df_inputs.luminance_circumsolar.values
poa_horizon = df_inputs.poa_horizon.values
poa_circumsolar_front = df_inputs.poa_circumsolar.values
# Calculate AOI on front pvrow using pvlib implementation
aoi_front_pvrow = aoi_function(surface_tilt, surface_azimuth,
solar_zenith, solar_azimuth)
aoi_back_pvrow = 180. - aoi_front_pvrow
# Will be used for back surface adjustments: from Perez model
# FIXME: pvlib clips the angle values to calculate vf -> adjust here
vf_circumsolar_backsurface = cosd(aoi_back_pvrow) / cosd(solar_zenith)
poa_circumsolar_back = luminance_circumsolar * vf_circumsolar_backsurface
# Return only >0 values for poa_horizon
poa_horizon = np.abs(poa_horizon)
return luminance_isotropic, luminance_circumsolar, poa_horizon, \
poa_circumsolar_front, poa_circumsolar_back, \
aoi_front_pvrow, aoi_back_pvrow