add irradiance and weather kwargs to run_model

Author: wholmgren

docs/sphinx/source/package_overview.rst

@@ -33,23 +33,31 @@ configuration at a handful of sites listed below.
 
     import pandas as pd
     import matplotlib.pyplot as plt
+    
+    # seaborn makes the plots look nicer
     import seaborn as sns
     sns.set_color_codes()
     
     times = pd.DatetimeIndex(start='2015', end='2016', freq='1h')
     
     # very approximate
+    # latitude, longitude, name, altitude
     coordinates = [(30, -110, 'Tucson', 700),
                    (35, -105, 'Albuquerque', 1500),
                    (40, -120, 'San Francisco', 10),
                    (50, 10, 'Berlin', 34)]
     
     import pvlib
     
+    # get the module and inverter specifications from SAM
     sandia_modules = pvlib.pvsystem.retrieve_sam('SandiaMod')
     sapm_inverters = pvlib.pvsystem.retrieve_sam('sandiainverter')
     module = sandia_modules['Canadian_Solar_CS5P_220M___2009_']
     inverter = sapm_inverters['ABB__MICRO_0_25_I_OUTD_US_208_208V__CEC_2014_']
+    
+    # specify constant ambient air temp and wind
+    temp_air = 20
+    wind_speed = 0
 
 
 Procedural
@@ -85,7 +93,8 @@ to accomplish our system modeling goal:
                                                    cs['dni'], cs['ghi'], cs['dhi'],
                                                    dni_extra=dni_extra,
                                                    model='haydavies')
-        temps = pvlib.pvsystem.sapm_celltemp(total_irrad['poa_global'], 0, 20)
+        temps = pvlib.pvsystem.sapm_celltemp(total_irrad['poa_global'],
+                                             wind_speed, temp_air)
         dc = pvlib.pvsystem.sapm(module, total_irrad['poa_direct'],
                                  total_irrad['poa_diffuse'], temps['temp_cell'],
                                  am_abs, aoi)
@@ -140,6 +149,7 @@ objects to accomplish our system modeling goal:
         # very experimental
         mc = ModelChain(system, location,
                         orientation_strategy='south_at_latitude_tilt')
+        # optional parameters for irradiance and weather data
         dc, ac = mc.run_model(times)
         annual_energy = ac.sum()
         energies[name] = annual_energy
@@ -188,7 +198,8 @@ object to accomplish our modeling goal:
                                                       clearsky['dni'],
                                                       clearsky['ghi'],
                                                       clearsky['dhi'])
-        temps = localized_system.sapm_celltemp(total_irrad['poa_global'], 0, 20)
+        temps = localized_system.sapm_celltemp(total_irrad['poa_global'],
+                                               wind_speed, temp_air)
         aoi = localized_system.get_aoi(solar_position['apparent_zenith'],
                                        solar_position['azimuth'])
         am_rel = pvlib.atmosphere.relativeairmass(solar_position['apparent_zenith'])

pvlib/modelchain.py

@@ -86,31 +86,45 @@ def orientation_strategy(self, strategy):
         self._orientation_strategy = strategy
 
 
-    def run_model(self, times):
+    def run_model(self, times=None, irradiance=None, weather=None):
         """
         Run the model.
         
-        Problems:
-        
-        * assumes clear sky
-        * assumes 0 m/s wind and 20 C temp.
-        * only works with SAPM
-        
+        Parameters
+        ----------
+        times : None or DatetimeIndex
+        irradiance : None or DataFrame
+            If None, calculates clear sky data.
+            Columns must be 'dni', 'ghi', 'dhi'
+        weather : None or DataFrame
+            If None, assumes air temperature is 20 C and
+            wind speed is 0 m/s.
+            Columns must be 'wind_speed', 'temp_air'.
+
         Returns
         -------
         output : DataFrame
             Some combination of AC power, DC power, POA irrad, etc.
         """
         solar_position = self.location.get_solarposition(times)
-        clearsky = self.location.get_clearsky(solar_position.index,
-                                              self.clearsky_model)
-        irradiance = self.system.get_irradiance(solar_position['apparent_zenith'],
-                                                solar_position['azimuth'],
-                                                clearsky['dni'],
-                                                clearsky['ghi'],
-                                                clearsky['dhi'],
-                                                model=self.transposition_model)
-        temps = self.system.sapm_celltemp(irradiance['poa_global'], 0, 20)
+        
+        if irradiance is None:
+            irradiance = self.location.get_clearsky(solar_position.index,
+                                                    self.clearsky_model)
+
+        total_irrad = self.system.get_irradiance(solar_position['apparent_zenith'],
+                                                 solar_position['azimuth'],
+                                                 irradiance['dni'],
+                                                 irradiance['ghi'],
+                                                 irradiance['dhi'],
+                                                 model=self.transposition_model)
+                                                
+        if weather is None:
+            weather = {'wind_speed': 0, 'temp_air': 20}
+
+        temps = self.system.sapm_celltemp(total_irrad['poa_global'],
+                                          weather['wind_speed'],
+                                          weather['temp_air'])
 
         aoi = self.system.get_aoi(solar_position['apparent_zenith'],
                                   solar_position['azimuth'])
@@ -119,8 +133,9 @@ def run_model(self, times):
                                             self.airmass_model)
         am_abs = self.location.get_absoluteairmass(am_rel)
 
-        dc = self.system.sapm(irradiance['poa_direct'],
-                              irradiance['poa_diffuse'], temps['temp_cell'],
+        dc = self.system.sapm(total_irrad['poa_direct'],
+                              total_irrad['poa_diffuse'],
+                              temps['temp_cell'],
                               am_abs, aoi)
 
         ac = self.system.snlinverter(dc['v_mp'], dc['p_mp'])