Skip to content

Adds k parameter to temperature.ross #2521

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 14 commits into
base: main
Choose a base branch
from
Open

Adds k parameter to temperature.ross #2521

Show file tree
Hide file tree
Changes from 5 commits
Commits
Show all changes
14 commits
Select commit Hold shift + click to select a range
85aa720
Adds k parameter to temperature.ross
ramaroesilva Jul 31, 2025
50da75f
Updates whatsnew file for v13.1
ramaroesilva Jul 31, 2025
48866ee
Corrects minor typos.
ramaroesilva Jul 31, 2025
c917c61
Corrects doi formatting.
ramaroesilva Jul 31, 2025
b3b10fc
Improve docstring and initial test messages.
ramaroesilva Jul 31, 2025
70616e1
Adds tests for temperature.ross
ramaroesilva Aug 1, 2025
b71960b
Changes variables in test from int to float.
ramaroesilva Aug 1, 2025
c3edec5
Merge branch 'main' into ross-k
ramaroesilva Aug 1, 2025
3d8db5e
Addresses flake8 issues.
ramaroesilva Aug 1, 2025
3766673
Resolves conflict in whatsnew file.
ramaroesilva Aug 1, 2025
058e1f0
Fixes flake8 issue.
ramaroesilva Aug 1, 2025
97535a0
Covers errors in testing temperature.ross
ramaroesilva Aug 1, 2025
0cc4b5f
Improves documentation on temperature.ross
ramaroesilva Aug 1, 2025
fd72680
Corrects minor typo.
ramaroesilva Aug 1, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 7 additions & 3 deletions docs/sphinx/source/whatsnew/v0.13.1.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,11 @@ Bug fixes

Enhancements
~~~~~~~~~~~~


* Rename parameter name ``aparent_azimuth`` to ``solar_azimuth`` in :py:func:`~pvlib.tracking.singleaxis`.
(:issue:`2479`, :pull:`2480`)
* Add k coefficient in :py:func:`~pvlib.temperature.ross`
(:issue:`2506`, :pull:`2521`)

Documentation
~~~~~~~~~~~~~
* Substantiate definitions of solar/surface azimuth/zenith and aoi on the
Expand Down Expand Up @@ -48,4 +51,5 @@ Contributors
~~~~~~~~~~~~
* Elijah Passmore (:ghuser:`eljpsm`)
* Rajiv Daxini (:ghuser:`RDaxini`)
* Omar Bahamida (:ghuser:`OmarBahamida`)
* Omar Bahamida (:ghuser:`OmarBahamida`)
* Rodrigo Amaro e Silva (:ghuser:`ramaroesilva`)
44 changes: 40 additions & 4 deletions pvlib/temperature.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -618,7 +618,7 @@ def faiman_rad(poa_global, temp_air, wind_speed=1.0, ir_down=None,
return temp_air + temp_difference


def ross(poa_global, temp_air, noct):
def ross(poa_global, temp_air, noct=None, k=None):
r'''
Calculate cell temperature using the Ross model.

Expand All @@ -638,6 +638,9 @@ def ross(poa_global, temp_air, noct):
noct : numeric
Nominal operating cell temperature [C], determined at conditions of
800 W/m^2 irradiance, 20 C ambient air temperature and 1 m/s wind.
k: numeric
Ross coefficient [Km^2/W], which is an alternative to employing
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Suggested change
Ross coefficient [Km^2/W], which is an alternative to employing
Ross coefficient [Km²W⁻¹], which is an alternative to employing

Copy link
Member

@cwhanse cwhanse Aug 15, 2025 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Last comment for me: We should mark both noct and k as optional. I can't suggest for a line that isn't being modified, but it would be like this:

    noct: numeric, optional
        Nominal operating cell temperature [C], determined at conditions of
        800 W/m^2 irradiance, 20 C ambient air temperature and 1 m/s wind.
        If ``noct`` is not provided, ``k`` is required.

And similar for k

The double ticks "``" format the enclosed string as a parameter.

NOCT in Ross's equation.

Returns
-------
Expand All @@ -650,19 +653,52 @@ def ross(poa_global, temp_air, noct):

.. math::

T_{C} = T_{a} + \frac{NOCT - 20}{80} S
T_{C} = T_{a} + \frac{NOCT - 20}{80} S = T_{a} + k × S

where :math:`S` is the plane of array irradiance in :math:`mW/{cm}^2`.
This function expects irradiance in :math:`W/m^2`.
Comment on lines 658 to 659
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Let others comment, but I think Wm⁻² looks cleaner than the larger font bolt+italic math type for units. Might be worth saving that for variables(?)
At least if sticking with :math: then I think superscript would be better than a /: `:math:`mW{cm}^{-2}

Suggested change
where :math:`S` is the plane of array irradiance in :math:`mW/{cm}^2`.
This function expects irradiance in :math:`W/m^2`.
where :math:`S` is the plane of array irradiance in mWm⁻².
This function expects irradiance in Wm⁻².


Representative values for k are provided in [2]_, covering different types
of mounting and module structure.

+---------------------+-----------+
| Mounting | :math:`k` |
+=====================+===========+
| Well cooled | 0.02 |
+---------------------+-----------+
| Free standing | 0.0208 |
+---------------------+-----------+
| Flat on roof | 0.026 |
+---------------------+-----------+
| Not so well cooled | 0.0342 |
+---------------------+-----------+
| Transparent pv | 0.0455 |
+---------------------+-----------+
| Facade integrated | 0.0538 |
+---------------------+-----------+
| On sloped roof | 0.0563 |
+---------------------+-----------+

References
----------
.. [1] Ross, R. G. Jr., (1981). "Design Techniques for Flat-Plate
Photovoltaic Arrays". 15th IEEE Photovoltaic Specialist Conference,
Orlando, FL.
.. [2] E. Skoplaki and J. A. Palyvos, “Operating temperature of
photovoltaic modules: A survey of pertinent correlations,” Renewable
Energy, vol. 34, no. 1, pp. 23–29, Jan. 2009,
:doi:`10.1016/j.renene.2008.04.009`
'''
# factor of 0.1 converts irradiance from W/m2 to mW/cm2
return temp_air + (noct - 20.) / 80. * poa_global * 0.1
if (noct is None) & (k is None):
raise ValueError("Either noct or k need is required.")
elif (noct is not None) & (k is not None):
raise ValueError("Provide only one of noct or k, not both.")
elif k is None:
# factor of 0.1 converts irradiance from W/m2 to mW/cm2
return temp_air + (noct - 20.) / 80. * poa_global * 0.1
elif noct is None:
# k assumes irradiance in W.m-2, dismissing 0.1 factor
return temp_air + k * poa_global


def _fuentes_hconv(tave, windmod, tinoct, temp_delta, xlen, tilt,
Expand Down