8000 add temperature.sapm_cell_from_module (#938) · Ahanmr/pvlib-python@06f8f6e · GitHub
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add temperature.sapm_cell_from_module (pvlib#938)
* add temperature.sapm_cell_to_module * add See also to docstring * Update pvlib/temperature.py Co-Authored-By: Will Holmgren <william.holmgren@gmail.com> * remove hyphen * remove ~ from function paths Co-authored-by: Will Holmgren <william.holmgren@gmail.com>
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‎docs/sphinx/source/api.rst

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@@ -232,6 +232,7 @@ PV temperature models
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temperature.sapm_cell
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temperature.sapm_module
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temperature.sapm_cell_from_module
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temperature.pvsyst_cell
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temperature.faiman
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‎docs/sphinx/source/whatsnew/v0.7.2.rst

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@@ -21,13 +21,17 @@ Enhancements
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* TMY3 dataframe returned by :py:func:`~pvlib.iotools.read_tmy3` now contains
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the original ``Date (MM/DD/YYYY)`` and ``Time (HH:MM)`` columns that the
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indices were parsed from. (:pull:`866`)
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* Add :py:func:`~pvlib.pvsystem.PVSystem.faiman` and added
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* Add :py:func:`pvlib.pvsystem.PVSystem.faiman` and added
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``temperature_model='faiman'`` option to :py:class:`~pvlib.modelchain.ModelChain`
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(:pull:`897`) (:issue:`836`).
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* Add Kimber soiling model :py:func:`pvlib.losses.soiling_kimber`. (:pull:`860`)
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* Add :py:func:`pvlib.iotools.read_pvgis_tmy` for files downloaded using the
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* Add Kimber soiling model :py:func:`pvlib.soiling.kimber`. (:pull:`860`,
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:issue`935`)
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* Add :func:`~pvlib.iotools.read_pvgis_tmy` for files downloaded using the
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PVGIS tool. (:issue:`880`)
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* Add :py:func:`pvlib.temperature.sapm_cell_from_module` to convert back of
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module temperature to cell temperature (:issue:`927`)
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* Add new module :py:mod:`pvlib.snow` to contain models related to snow coverage and effects on a PV system. (:pull:`764`)
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* Add snow coverage model :py:func:`pvlib.snow.coverage_nrel` and function to identify when modules are fully covered by snow :py:func:`pvlib.snow.fully_covered_nrel`. (:issue:`577`)
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* Add function :py:func:`pvlib.snow.dc_loss_nrel` for effect of snow coverage on DC output. (:pull:`764`)

‎pvlib/temperature.py

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@@ -33,7 +33,7 @@ def _temperature_model_params(model, parameter_set):
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def sapm_cell(poa_global, temp_air, wind_speed, a, b, deltaT,
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irrad_ref=1000):
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r'''
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Calculate cell temperature per the Sandia PV Array Performance Model.
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Calculate cell temperature per the Sandia Array Performance Model.
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See [1]_ for details on the Sandia Array Performance Model.
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@@ -107,6 +107,11 @@ def sapm_cell(poa_global, temp_air, wind_speed, a, b, deltaT,
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Model", SAND Report 3535, Sandia National Laboratories, Albuquerque,
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NM.
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See also
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--------
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sapm_cell_from_module
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sapm_module
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Examples
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--------
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>>> from pvlib.temperature import sapm_cell, TEMPERATURE_MODEL_PARAMETERS
@@ -116,12 +121,13 @@ def sapm_cell(poa_global, temp_air, wind_speed, a, b, deltaT,
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'''
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module_temperature = sapm_module(poa_global, temp_air, wind_speed,
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a, b)
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return module_temperature + (poa_global / irrad_ref) * deltaT
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return sapm_cell_from_module(module_temperature, poa_global, deltaT,
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irrad_ref)
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def sapm_module(poa_global, temp_air, wind_speed, a, b):
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r'''
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Calculate module back surface temperature per the Sandia PV Array
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Calculate module back surface temperature per the Sandia Array
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Performance Model.
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See [1]_ for details on the Sandia Array Performance Model.
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Model", SAND Report 3535, Sandia National Laboratories, Albuquerque,
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NM.
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See also
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--------
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sapm_cell
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sapm_cell_from_module
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'''
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return poa_global * np.exp(a + b * wind_speed) + temp_air
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def sapm_cell_from_module(module_temperature, poa_global, deltaT,
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irrad_ref=1000):
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r'''
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Calculate cell temperature from module temperature using the Sandia Array
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Performance Model.
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See [1]_ for details on the Sandia Array Performance Model.
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Parameters
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----------
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module_temperature : numeric
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Temperature of back of module surface [C].
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poa_global : numeric
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Total incident irradiance [W/m^2].
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deltaT : float
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Parameter :math:`\Delta T` in :eq:`sapm2` [C].
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irrad_ref : float, default 1000
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Reference irradiance, parameter :math:`E_{0}` in
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:eq:`sapm2` [W/m^2].
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Returns
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-------
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numeric, values in degrees C.
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Notes
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-----
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The model for cell temperature :math:`T_{C}` is given by Eq. 12 in [1]_.
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.. math::
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:label: sapm2
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T_{C} = T_{m} + \frac{E}{E_{0}} \Delta T
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The module back surface temperature :math:`T_{m}` is implemented in
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:py:func:`~pvlib.temperature.sapm_module`.
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Model parameters depend both on the module construction and its mounting.
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Parameter sets are provided in [1]_ for representative modules and
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mounting, and are coded for convenience in
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``pvlib.temperature.TEMPERATURE_MODEL_PARAMETERS``.
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+---------------+----------------+-------+---------+---------------------+
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| Module | Mounting | a | b | :math:`\Delta T [C]`|
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+===============+================+=======+=========+=====================+
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| glass/glass | open rack | -3.47 | -0.0594 | 3 |
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+---------------+----------------+-------+---------+---------------------+
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| glass/glass | close roof | -2.98 | -0.0471 | 1 |
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+---------------+----------------+-------+---------+---------------------+
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| glass/polymer | open rack | -3.56 | -0.075 | 3 |
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+---------------+----------------+-------+---------+---------------------+
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| glass/polymer | insulated back | -2.81 | -0.0455 | 0 |
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+---------------+----------------+-------+---------+---------------------+
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References
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----------
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.. [1] King, D. et al, 2004, "Sandia Photovoltaic Array Performance
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Model", SAND Report 3535, Sandia National Laboratories, Albuquerque,
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NM.
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See also
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--------
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sapm_cell
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sapm_module
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'''
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return module_temperature + (poa_global / irrad_ref) * deltaT
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def pvsyst_cell(poa_global, temp_air, wind_speed=1.0, u_c=29.0, u_v=0.0,
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eta_m=0.1, alpha_absorption=0.9):
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r"""

‎pvlib/tests/test_temperature.py

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@@ -26,6 +26,12 @@ def test_sapm_module(sapm_default):
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assert_allclose(default, 40.809, 3)
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def test_sapm_cell_from_module(sapm_default):
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default = temperature.sapm_cell_from_module(50, 900,
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sapm_default['deltaT'])
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assert_allclose(default, 50 + 900 / 1000 * sapm_default['deltaT'])
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def test_sapm_ndarray(sapm_default):
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temps = np.array([0, 10, 5])
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irrads = np.array([0, 500, 0])

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