Use k and cap_adjustment from Array.module_parameters in PVSystem.pvwatts_dc (#2715)

* Update _build_kwargs call in PVSystem.pvwatts_dc to include 'k' and 'cap_adjustment' parameters

* Add 'k' and 'cap_adjustment' parameters to module_parameters in pvwatts_system_kwargs fixture

* Add enhancement entry in v0.15.1 release notes and add contributor

* Update docstring in PVSystem.pvwatts_dc

* Fix linting failure

* Fix linting failure

* Update docstring in PVSystem.pvwatts_dc

Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>

* Apply suggestion from @RDaxini

Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

---------

Co-authored-by: Cliff Hansen <cwhanse@sandia.gov>
Co-authored-by: Rajiv Daxini <143435106+RDaxini@users.noreply.github.com>

Author: 3 people

docs/sphinx/source/whatsnew/v0.15.1.rst

@@ -20,7 +20,9 @@ Bug fixes
 
 Enhancements
 ~~~~~~~~~~~~
-
+* Use ``k`` and ``cap_adjustment`` from :py:func:`pvlib.pvsystem.Array.module_parameters` in :py:func:`pvlib.pvsystem.PVSystem.pvwatts_dc`
+  (:issue:`2714`, :pull:`2715`)
+  
 
 Documentation
 ~~~~~~~~~~~~~
@@ -70,4 +72,5 @@ Contributors
 * Anton Driesse (:ghuser:`adriesse`)
 * Kevin Anderson (:ghuser:`kandersolar`)
 * Rohan Saxena (:ghuser:`r0hansaxena`)
+* Marco Fumagalli (:ghuser:`fuma900`)
 

pvlib/pvsystem.py

@@ -850,7 +850,10 @@ def pvwatts_dc(self, effective_irradiance, temp_cell):
         """
         Calculates DC power according to the PVWatts model using
         :py:func:`pvlib.pvsystem.pvwatts_dc`, `self.module_parameters['pdc0']`,
-        and `self.module_parameters['gamma_pdc']`.
+        `self.module_parameters['gamma_pdc']`,
+        `self.module_parameters['temp_ref']`, and optionally,
+        `self.module_parameters['k']` and
+        `self.module_parameters['cap_adjustment']`.
 
         See :py:func:`pvlib.pvsystem.pvwatts_dc` for details.
         """
@@ -860,7 +863,8 @@ def pvwatts_dc(self, effective_irradiance, temp_cell):
             pvwatts_dc(effective_irradiance, temp_cell,
                        array.module_parameters['pdc0'],
                        array.module_parameters['gamma_pdc'],
-                       **_build_kwargs(['temp_ref'], array.module_parameters))
+                       **_build_kwargs(['temp_ref', 'k', 'cap_adjustment'],
+                                       array.module_parameters))
             for array, effective_irradiance, temp_cell
             in zip(self.arrays, effective_irradiance, temp_cell)
         )

tests/test_pvsystem.py

@@ -2260,7 +2260,8 @@ def pvwatts_system_defaults():
 
 @pytest.fixture
 def pvwatts_system_kwargs():
-    module_parameters = {'pdc0': 100, 'gamma_pdc': -0.003, 'temp_ref': 20}
+    module_parameters = {'pdc0': 100, 'gamma_pdc': -0.003, 'temp_ref': 20,
+                         'k': 0.01, 'cap_adjustment': True}
     inverter_parameters = {'pdc0': 90, 'eta_inv_nom': 0.95, 'eta_inv_ref': 1.0}
     system = pvsystem.PVSystem(module_parameters=module_parameters,
                                inverter_parameters=inverter_parameters)