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Add optional arguments temperature_ref and irradiance_ref to pvsystem.sapm #2434

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Merged
merged 16 commits into from
Apr 21, 2025
Merged

Add optional arguments temperature_ref and irradiance_ref to pvsystem.sapm #2434

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a564b32
add ref irr/t as optional args, rename
RDaxini Apr 10, 2025
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add terms to docs
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linter
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Update v0.12.1.rst
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move whatsnew entry from docs to enhancements
RDaxini Apr 10, 2025
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multiple instances of C -> °C
RDaxini Apr 11, 2025
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name change (#825)
RDaxini Apr 11, 2025
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Update v0.12.1.rst
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Merge remote-tracking branch 'upstream/main' into pvsystem_ref_temp_irr
RDaxini Apr 11, 2025
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missing `
RDaxini Apr 14, 2025
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remove unused package
RDaxini Apr 14, 2025
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change to kwarg only parameters
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update names, remove duplicate entry
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remove ivtools line. mistakenly added during merge branch?
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3 changes: 2 additions & 1 deletion docs/sphinx/source/whatsnew/v0.12.1.rst
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Expand Up @@ -15,7 +15,8 @@ Bug fixes
Enhancements
~~~~~~~~~~~~
* ``pvlib.ivtools.sdm`` is now a subpackage. (:issue:`2252`, :pull:`2256`)

* Add optional arguments `reference_temperature` and `reference_irradiance` to
:py:func:`~pvlib.pvsystem.sapm`(:issue:`2432`, :pull:`2434`)

Documentation
~~~~~~~~~~~~~
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31 changes: 17 additions & 14 deletions pvlib/pvsystem.py
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Expand Up @@ -2195,7 +2195,8 @@ def _parse_raw_sam_df(csvdata):
return df


def sapm(effective_irradiance, temp_cell, module):
def sapm(effective_irradiance, temp_cell, module, reference_temperature=25,
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Suggested change
def sapm(effective_irradiance, temp_cell, module, reference_temperature=25,
def sapm(effective_irradiance, temp_cell, module, *, reference_temperature=25,

Consider using kwarg-only parameters to enforce readability of code. For future issues debugging, ...
Completely optional suggestion, it's not a common trend in pvlib.

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I'm not familiar with what this is doing actually... could you elaborate or forward a link for me to review?
You noted it's optional / uncommon in pvlib currently, so I'll just let others comment whether to go ahead with this as I have no idea 😅

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Quick lookup on the internet and you will have a ton of information more extensive, but here is a short example, where all statements are expected to print Hola Dax. The star means the following arguments are only allowed to be passed in as keyword-only (parameter_name=value):

def hola_dax(greet, name):
    print(f"{greet} {name}")

# allowed uses
hola_dax("Hola", "Dax")
hola_dax("Hola", name="Dax")
hola_dax(greet="Hola", name="Dax")
hola_dax(name="Dax", greet="Hola")

# however
def hola_dax(greet, *, name):
    print(f"{greet} {name}")
# only allows using the forms:
hola_dax("Hola", name="Dax")
hola_dax(greet="Hola", name="Dax")
# this raises an error:
hola_dax("Hola", "Dax")  # TypeError: hola_dax() takes 1 positional argument but 2 were given

# and the form
def hola_dax(*, greet, name):
    print(f"{greet} {name}")
# only allows:
hola_dax(greet="Hola", name="Dax")
hola_dax(name="Dax", greet="Hola")

This way, you can always enforce people to make readable code.

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Right ok got it! Seems like a good suggestion to me. Thanks @echedey-ls

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https://pvlib-python--2434.org.readthedocs.build/en/2434/reference/generated/pvlib.pvsystem.sapm.html#pvlib.pvsystem.sapm
Should * show here in the function, and if so is there any need to document that below in the parameter descriptions...?

reference_irradiance=1000):
'''
The Sandia PV Array Performance Model (SAPM) generates 5 points on a
PV module's I-V curve (Voc, Isc, Ix, Ixx, Vmp/Imp) according to
Expand All @@ -2205,7 +2206,7 @@ def sapm(effective_irradiance, temp_cell, module):
----------
effective_irradiance : numeric
Irradiance reaching the module's cells, after reflections and
adjustment for spectrum. [W/m2]
adjustment for spectrum. [Wm⁻²]

temp_cell : numeric
Cell temperature [C].
Expand All @@ -2214,6 +2215,12 @@ def sapm(effective_irradiance, temp_cell, module):
A dict or Series defining the SAPM parameters. See the notes section
for more details.

reference_temperature : numeric, optional
Reference temperature [C]

reference_irradiance : numeric, optional
Reference irradiance [Wm⁻²]

Returns
-------
A DataFrame with the columns:
Expand Down Expand Up @@ -2284,16 +2291,11 @@ def sapm(effective_irradiance, temp_cell, module):
pvlib.temperature.sapm_module
'''

# TODO: someday, change temp_ref and irrad_ref to reference_temperature and
# reference_irradiance and expose
temp_ref = 25
irrad_ref = 1000

q = constants.e # Elementary charge in units of coulombs
kb = constants.k # Boltzmann's constant in units of J/K

# avoid problem with integer input
Ee = np.array(effective_irradiance, dtype='float64') / irrad_ref
Ee = np.array(effective_irradiance, dtype='float64') / reference_irradiance

# set up masking for 0, positive, and nan inputs
Ee_gt_0 = np.full_like(Ee, False, dtype='bool')
Expand All @@ -2316,31 +2318,32 @@ def sapm(effective_irradiance, temp_cell, module):
out = OrderedDict()

out['i_sc'] = (
module['Isco'] * Ee * (1 + module['Aisc']*(temp_cell - temp_ref)))
module['Isco'] * Ee * (1 + module['Aisc']*(temp_cell -
reference_temperature)))

out['i_mp'] = (
module['Impo'] * (module['C0']*Ee + module['C1']*(Ee**2)) *
(1 + module['Aimp']*(temp_cell - temp_ref)))
(1 + module['Aimp']*(temp_cell - reference_temperature)))

out['v_oc'] = np.maximum(0, (
module['Voco'] + cells_in_series * delta * logEe +
Bvoco*(temp_cell - temp_ref)))
Bvoco*(temp_cell - reference_temperature)))

out['v_mp'] = np.maximum(0, (
module['Vmpo'] +
module['C2'] * cells_in_series * delta * logEe +
module['C3'] * cells_in_series * ((delta * logEe) ** 2) +
Bvmpo*(temp_cell - temp_ref)))
Bvmpo*(temp_cell - reference_temperature)))

out['p_mp'] = out['i_mp'] * out['v_mp']

out['i_x'] = (
module['IXO'] * (module['C4']*Ee + module['C5']*(Ee**2)) *
(1 + module['Aisc']*(temp_cell - temp_ref)))
(1 + module['Aisc']*(temp_cell - reference_temperature)))

out['i_xx'] = (
module['IXXO'] * (module['C6']*Ee + module['C7']*(Ee**2)) *
(1 + module['Aimp']*(temp_cell - temp_ref)))
(1 + module['Aimp']*(temp_cell - reference_temperature)))

if isinstance(out['i_sc'], pd.Series):
out = pd.DataFrame(out)
Expand Down