def test_noct_sam_against_sam():
# test is constructed to reproduce output from SAM v2020.11.29.
# SAM calculation is the default Detailed PV System model (CEC diode model,
# NOCT cell temperature model), with the only change being the soiling
# loss is set to 0. Weather input is TMY3 for Phoenix AZ.
# Values are taken from the Jan 1 12:00:00 timestamp.
poa_total, temp_air, wind_speed, noct, module_efficiency = (
860.673, 25, 3, 46.4, 0.20551)
poa_total_after_refl = 851.458 # from SAM output
# compute effective irradiance
# spectral loss coefficients fixed in lib_cec6par.cpp
a = np.flipud([0.918093, 0.086257, -0.024459, 0.002816, -0.000126])
# reproduce SAM air mass calculation
zen = 56.4284
elev = 358
air_mass = 1. / (tools.cosd(zen) + 0.5057 * (96.080 - zen)**-1.634)
air_mass *= np.exp(-0.0001184 * elev)
f1 = np.polyval(a, air_mass)
effective_irradiance = f1 * poa_total_after_refl
transmittance_absorptance = 0.9
array_height = 1
mount_standoff = 4.0
result = temperature.noct_sam(poa_total, temp_air, wind_speed, noct,
module_efficiency, effective_irradiance,
transmittance_absorptance, array_height,
mount_standoff)
expected = 43.0655
# rtol from limited SAM output precision
assert_allclose(result, expected, rtol=1e-5)
def test_noct_sam():
poa_global, temp_air, wind_speed, noct, module_efficiency = (
1000., 25., 1., 45., 0.2)
expected = 55.230790492
result = temperature.noct_sam(poa_global, temp_air, wind_speed, noct,
module_efficiency)
assert_allclose(result, expected)
# test with different types
result = temperature.noct_sam(np.array(poa_global), np.array(temp_air),
np.array(wind_speed), np.array(noct),
np.array(module_efficiency))
assert_allclose(result, expected)
dr = pd.date_range(start='2020-01-01 12:00:00', end='2020-01-01 13:00:00',
freq='1H')
result = temperature.noct_sam(pd.Series(index=dr, data=poa_global),
pd.Series(index=dr, data=temp_air),
pd.Series(index=dr, data=wind_speed),
pd.Series(index=dr, data=noct),
module_efficiency)
assert_series_equal(result, pd.Series(index=dr, data=expected))
def test_noct_sam_options():
poa_global, temp_air, wind_speed, noct, module_efficiency = (
1000., 25., 1., 45., 0.2)
effective_irradiance = 1100.
transmittance_absorptance = 0.8
array_height = 2
mount_standoff = 2.0
result = temperature.noct_sam(poa_global, temp_air, wind_speed, noct,
module_efficiency, effective_irradiance,
transmittance_absorptance, array_height,
mount_standoff)
expected = 60.477703576
assert_allclose(result, expected)
def test_noct_sam_errors():
with pytest.raises(ValueError):
temperature.noct_sam(1000., 25., 1., 34., 0.2, array_height=3)