diff --git a/docs/sphinx/source/whatsnew/v0.11.2.rst b/docs/sphinx/source/whatsnew/v0.11.2.rst index 087697f778..4434e10097 100644 --- a/docs/sphinx/source/whatsnew/v0.11.2.rst +++ b/docs/sphinx/source/whatsnew/v0.11.2.rst @@ -47,6 +47,9 @@ Documentation page, using the sphinx glossary directive. (:issue:`1421`, :pull:`2234`) * Explained how to write docstrings for new functions in :ref:`example-docstring` (:discussion:`2081`, :pull:`2254`) +* Clarify mounting cases for parameters for :py:func:`~pvlib.temperature.sapm_module`, + :py:func:`~pvlib.temperature.sapm_cell` and :py:func:`~pvlib.temperature.pvsyst_cell`. + (:issue:`1323`, :pull:`2293`) * Added the following variables to the :ref:`nomenclature` page: - `spectra` and `spectra_components` (:issue:`2150`, :pull:`2264`) diff --git a/pvlib/pvsystem.py b/pvlib/pvsystem.py index 03cf782391..f99f0275af 100644 --- a/pvlib/pvsystem.py +++ b/pvlib/pvsystem.py @@ -168,9 +168,12 @@ class PVSystem: Inverter parameters as defined by the SAPM, CEC, or other. racking_model : string, optional - Valid strings are 'open_rack', 'close_mount', 'freestanding', - 'insulated', or 'insulated_back'. - Used to identify a parameter set for the cell temperature model. + Valid strings are ``'open_rack'``, ``'close_mount'``, + ``'insulated_back'``, ``'freestanding'`` and ``'insulated'``. + Used to identify a parameter set for the SAPM or PVsyst cell + temperature model. + See :py:func:`~pvlib.temperature.sapm_module` and + :py:func:`~pvlib.temperature.pvsyst_cell` for definitions. losses_parameters : dict or Series, optional Losses parameters as defined by PVWatts or other. @@ -1393,9 +1396,12 @@ class FixedMount(AbstractMount): West=270. [degrees] racking_model : str, optional - Valid strings are 'open_rack', 'close_mount', 'freestanding', - 'insulated', or 'insulated_back'. - Used to identify a parameter set for the cell temperature model. + Valid strings are ``'open_rack'``, ``'close_mount'``, + ``'insulated_back'``, ``'freestanding'`` and ``'insulated'``. + Used to identify a parameter set for the SAPM or PVsyst cell + temperature model. + See :py:func:`~pvlib.temperature.sapm_module` and + :py:func:`~pvlib.temperature.pvsyst_cell` for definitions. module_height : float, optional The height above ground of the center of the module [m]. Used for @@ -1471,9 +1477,13 @@ class SingleAxisTrackerMount(AbstractMount): `cross_axis_tilt`. [degrees] racking_model : str, optional - Valid strings are 'open_rack', 'close_mount', 'freestanding', - 'insulated', or 'insulated_back'. - Used to identify a parameter set for the cell temperature model. + Valid strings are ``'open_rack'``, ``'close_mount'``, + ``'insulated_back'``, ``'freestanding'`` and ``'insulated'``. + Used to identify a parameter set for the SAPM or PVsyst cell + temperature model. ``'open_rack'`` or ``'freestanding'`` should + be used for systems with single-axis trackers. + See :py:func:`~pvlib.temperature.sapm_module` and + :py:func:`~pvlib.temperature.pvsyst_cell` for definitions. module_height : float, optional The height above ground of the center of the module [m]. Used for diff --git a/pvlib/temperature.py b/pvlib/temperature.py index 6269014969..ab31ffaf56 100644 --- a/pvlib/temperature.py +++ b/pvlib/temperature.py @@ -118,13 +118,25 @@ def sapm_cell(poa_global, temp_air, wind_speed, a, b, deltaT, +===============+================+=======+=========+=====================+ | glass/glass | open rack | -3.47 | -0.0594 | 3 | +---------------+----------------+-------+---------+---------------------+ - | glass/glass | close roof | -2.98 | -0.0471 | 1 | + | glass/glass | close mount | -2.98 | -0.0471 | 1 | +---------------+----------------+-------+---------+---------------------+ | glass/polymer | open rack | -3.56 | -0.075 | 3 | +---------------+----------------+-------+---------+---------------------+ | glass/polymer | insulated back | -2.81 | -0.0455 | 0 | +---------------+----------------+-------+---------+---------------------+ + Mounting cases can be described in terms of air flow across and around the + rear-facing surface of the module: + + * "open rack" refers to mounting that allows relatively free air flow. + This case is typical of ground-mounted systems on fixed racking or + single axis trackers. + * "close mount" refers to limited or restricted air flow. This case is + typical of roof-mounted systems with some gap behind the module. + * "insulated back" refers to systems with no air flow contacting the rear + surface of the module. This case is typical of building-integrated PV + systems, or systems laid flat on a ground surface. + References ---------- .. [1] King, D. et al, 2004, "Sandia Photovoltaic Array Performance @@ -199,13 +211,25 @@ def sapm_module(poa_global, temp_air, wind_speed, a, b): +===============+================+=======+=========+=====================+ | glass/glass | open rack | -3.47 | -0.0594 | 3 | +---------------+----------------+-------+---------+---------------------+ - | glass/glass | close roof | -2.98 | -0.0471 | 1 | + | glass/glass | close mount | -2.98 | -0.0471 | 1 | +---------------+----------------+-------+---------+---------------------+ | glass/polymer | open rack | -3.56 | -0.075 | 3 | +---------------+----------------+-------+---------+---------------------+ | glass/polymer | insulated back | -2.81 | -0.0455 | 0 | +---------------+----------------+-------+---------+---------------------+ + Mounting cases can be described in terms of air flow across and around the + rear-facing surface of the module: + + * "open rack" refers to mounting that allows relatively free air flow. + This case is typical of ground-mounted systems on fixed racking or + single axis trackers. + * "close mount" refers to limited or restricted air flow. This case is + typical of roof-mounted systems with some gap behind the module. + * "insulated back" refers to systems with no air flow contacting the rear + surface of the module. This case is typical of building-integrated PV + systems, or systems laid flat on a ground surface. + References ---------- .. [1] King, D. et al, 2004, "Sandia Photovoltaic Array Performance @@ -269,13 +293,25 @@ def sapm_cell_from_module(module_temperature, poa_global, deltaT, +===============+================+=======+=========+=====================+ | glass/glass | open rack | -3.47 | -0.0594 | 3 | +---------------+----------------+-------+---------+---------------------+ - | glass/glass | close roof | -2.98 | -0.0471 | 1 | + | glass/glass | close mount | -2.98 | -0.0471 | 1 | +---------------+----------------+-------+---------+---------------------+ | glass/polymer | open rack | -3.56 | -0.075 | 3 | +---------------+----------------+-------+---------+---------------------+ | glass/polymer | insulated back | -2.81 | -0.0455 | 0 | +---------------+----------------+-------+---------+---------------------+ + Mounting cases can be described in terms of air flow across and around the + rear-facing surface of the module: + + * "open rack" refers to mounting that allows relatively free air flow. + This case is typical of ground-mounted systems on fixed racking or + single axis trackers. + * "close mount" refers to limited or restricted air flow. This case is + typical of roof-mounted systems with some gap behind the module. + * "insulated back" refers to systems with no air flow contacting the rear + surface of the module. This case is typical of building-integrated PV + systems, or systems laid flat on a ground surface. + References ---------- .. [1] King, D. et al, 2004, "Sandia Photovoltaic Array Performance @@ -360,6 +396,16 @@ def pvsyst_cell(poa_global, temp_air, wind_speed=1.0, u_c=29.0, u_v=0.0, | insulated | 15.0 | 0.0 | +--------------+---------------+---------------+ + Mounting cases can be described in terms of air flow across and around the + rear-facing surface of the module: + + * "freestanding" refers to mounting that allows relatively free air + circulation around the modules. This case is typical of ground-mounted + systems on tilted, fixed racking or single axis trackers. + * "insulated" refers to mounting with air flow across only the front + surface. This case is typical of roof-mounted systems with no gap + behind the module. + References ---------- .. [1] "PVsyst 7 Help", [Online]. Available: