def test_marion_diffuse_model(mocker):
# 1: return values are correct
# 2: the underlying models are called appropriately
ashrae_expected = {
'sky': 0.9596085829811408,
'horizon': 0.8329070417832541,
'ground': 0.719823559106309
}
physical_expected = {
'sky': 0.9539178294437575,
'horizon': 0.7652650139134007,
'ground': 0.6387140117795903
}
ashrae_spy = mocker.spy(_iam, 'ashrae')
physical_spy = mocker.spy(_iam, 'physical')
ashrae_actual = _iam.marion_diffuse('ashrae', 20)
assert ashrae_spy.call_count == 3 # one call for each of the 3 regions
assert physical_spy.call_count == 0
physical_actual = _iam.marion_diffuse('physical', 20)
assert ashrae_spy.call_count == 3
assert physical_spy.call_count == 3
for k, v in ashrae_expected.items():
np.testing.assert_allclose(ashrae_actual[k], v)
for k, v in physical_expected.items():
np.testing.assert_allclose(physical_actual[k], v)
def test_marion_diffuse_kwargs():
# kwargs get passed to underlying model
expected = {
'sky': 0.967489994422575,
'horizon': 0.8647842827418412,
'ground': 0.7700443455928433
}
actual = _iam.marion_diffuse('ashrae', 20, b=0.04)
for k, v in expected.items():
np.testing.assert_allclose(actual[k], v)
def test_marion_diffuse_invalid():
with pytest.raises(ValueError):
_iam.marion_diffuse('not_a_model', 20)
plt.grid()
# %%
# Diffuse sky, ground, and horizon IAM
# ------------------------------------
#
# Now that we have an AOI model, we use :py:func:`pvlib.iam.marion_diffuse`
# to integrate it across solid angle and determine diffuse irradiance IAM.
# Marion defines three types of diffuse irradiance:
# sky, horizon, and ground-reflected. The diffuse IAM value is evaluated
# independently for each type.
tilts = np.arange(0, 91, 2.5)
# marion_diffuse calculates all three IAM values (sky, horizon, ground)
iam_no_coating = marion_diffuse('physical', tilts, n=1.526, K=0)
iam_ar_coating = marion_diffuse('physical', tilts, n=1.3, K=0)
# %%
# First we recreate Figure 4 in [1]_, showing the dependence of the sky diffuse
# incidence angle modifier on module tilt.
plt.plot(tilts,
iam_ar_coating['sky'],
c='b',
marker='^',
label='$F_{sky}$, AR coated, n=1.3')
plt.plot(tilts,
iam_no_coating['sky'],
c='r',
marker='x',