Update standards.py

Massive changes here but for the most part it is all about the standoff calculation which is working. One change to be aware of is that the prior calculations were using the module surface temperature for the standoff calculation but now it is using the cell temperature calculation.

Author: Kempe

pvdeg/standards.py

@@ -40,25 +40,35 @@ def eff_gap_parameters(
         Weather data for a single location.
     meta : pd.DataFrame
         Meta data for a single location.
-    tilt : float, 
-        Tilt angle of PV system relative to horizontal. 
-    azimuth : float, optional
-        Azimuth angle of PV system relative to north.
+
     sky_model : str, optional
         Options: 'isotropic', 'klucher', 'haydavies', 'reindl', 'king', 'perez'.
     temp_model : str, optional
         Options: 'sapm'.  'pvsyst' and 'faiman' will be added later.
-    conf_0 : str, optional
+        Performs the calculation for the cell temperature.
+    conf_0 : str, optional        Model for the high temperature module on the exponential decay curve.
         Default: 'insulated_back_glass_polymer'
     conf_inf : str, optional
+        Model for the lowest temperature module on the exponential decay curve.
         Default: 'open_rack_glass_polymer'
     wind_speed_factor : float, optional
         Wind speed correction factor to account for different wind speed measurement heights
         between weather database (e.g. NSRDB) and the tempeature model (e.g. SAPM)
         The NSRD provides calculations at 2m (i.e module height) but SAPM uses a 10m height.
-        It is recommended that a power-law relationship between height and wind speed of 0.33 be used.
-        This results in a wind_speed_factor of 1.7. It is acknowledged that this can vary significantly. 
-    
+        It is recommended that a power-law relationship between height and wind speed of 0.33 
+        be used. This results in a wind_speed_factor of 1.7. It is acknowledged that this can 
+        vary significantly. 
+
+    Meta data
+    ------------------
+    tilt : float, 
+        Tilt angle of PV system relative to horizontal. [°] Required
+    azimuth : float,
+        Azimuth angle of PV system relative to north. [°] Required
+    Anemomenter_Height_m : float,
+        if wind_speed_factor is "None", it will run a calculation based on this height and a 
+        power factor of 0.33. If neither are supplied a wind speed factor of 1 will be used.
+
     Returns
     -------
     T_0 : float
@@ -69,10 +79,12 @@ def eff_gap_parameters(
         An array of temperature values for a module that is rack mounted, [°C].
     T_measured : float
         An array of values for the test module in the system, [°C] interest.
+    poa : float
+        An array of values for the plane of array irradiance, [W/m²]
 
     """
 
-    parameters = ["temp_air", "wind_speed", "dhi", "ghi", "dni", "temp_measured"]
+    parameters = ["temp_air", "wind_speed", "dhi", "ghi", "dni", "Module_Temperature"]
 
     if isinstance(weather_df, dd.DataFrame):
         weather_df = weather_df[parameters].compute()
@@ -87,15 +99,22 @@ def eff_gap_parameters(
         weather_df,
         meta,
         sol_position=solar_position,
-        tilt=meta.tilt,
-        azimuth=meta.azimuth,
+        tilt=float(meta['Tilt']),
+        azimuth=float(meta['Azimuth']),
         sky_model=sky_model, )
-    T_0 = temperature.module(
-        weather_df, meta, poa, temp_model, conf_0, wind_speed_factor )
-    T_inf = temperature.module(
-        weather_df, meta, poa, temp_model, conf_inf, wind_speed_factor )
+    if wind_speed_factor is None:
+        if 'Anemometer_Height_m' in meta():
+            wind_speed_factor = (meta('Anemometer_Height_m')/2) ** 0.33 #Assumes a 2 meter height used in the module temperature model
+        else:
+            wind_speed_factor = 1
+    T_0 = temperature.cell(
+        weather_df=weather_df, meta=meta, poa=poa, temp_model=temp_model, conf=conf_0, 
+        wind_speed_factor=wind_speed_factor )
+    T_inf = temperature.cell(
+        weather_df=weather_df, meta=meta, poa=poa, temp_model=temp_model, conf=conf_inf, 
+        wind_speed_factor=wind_speed_factor )
     T_measured = weather_df.Module_Temperature
-    T_ambient = weather_df.temperature
+    T_ambient = weather_df.temp_air
 
     return T_0, T_inf, T_measured, T_ambient, poa
 
@@ -118,7 +137,7 @@ def eff_gap(T_0, T_inf, T_measured, T_ambient, poa, x_0=6.5, poa_min=100, t_amb_
         An array of values for the measured module temperature, [°C].
     T_ambient : float
         An array of values for the ambient temperature, [°C].
-        poa : float
+    poa : float
         An array of values for the plane of array irradiance, [W/m²]
     x_0 : float, optional
         Thermal decay constant [cm], [Kempe, PVSC Proceedings 2023].
@@ -139,18 +158,18 @@ def eff_gap(T_0, T_inf, T_measured, T_ambient, poa, x_0=6.5, poa_min=100, t_amb_
 
     n = 0
     summ = 0
-    for i in range(0, len(t_0)):
-        if T_ambient > t_amb_min:
-            if poa > poa_min:
+    for i in range(0, len(T_0)):
+        if T_ambient.iloc[i] > t_amb_min:
+            if poa.poa_global.iloc[i] > poa_min:
                 n = n + 1
-                summ = summ + (T_0[i] - T_module[i]) / (T_0[i] - T_inf[i])
+                summ = summ + (T_0.iloc[i] - T_measured.iloc[i]) / (T_0.iloc[i] - T_inf.iloc[i])
 
     try:
         x_eff = -x_0 * np.log(1 - summ/n)
     except RuntimeWarning as e:
         x_eff = np.nan # results if the specified T₉₈ is cooler than an open_rack temperature 
-    if x<0: 
-        x_eff=0 
+    if x_eff < 0: 
+        x_eff = 0 
 
     return x_eff
 
@@ -159,20 +178,23 @@ def standoff(
     weather_df=None,
     meta=None,
     weather_kwarg=None,
-    tilt=None,
-    azimuth=180,
+    tilt=0,
+    azimuth=None,
     sky_model="isotropic",
     temp_model="sapm",
-    #module_type="glass_polymer",  # This is removed forcing one to specify alternatives if desired
     conf_0="insulated_back_glass_polymer",
     conf_inf="open_rack_glass_polymer",
-    #level=1, # I am removing this because it is unnecessarily complicated
     T98=70, # [°C]
     x_0=6.5, # [cm]
     wind_speed_factor=1.7,
 ):
     """
-    Calculate a minimum standoff distance for roof mounded PV systems.
+    Calculate a minimum standoff distance for roof mounded PV systems. 
+    Will default to horizontal tilt. If the azimuth is not provided, it
+    will use equator facing.
+    You can use customized temperature models for the building integrated
+    and the rack mounted configuration, but it will still assume an
+    exponential decay.
 
     Parameters
     ----------
@@ -181,16 +203,19 @@ def standoff(
     meta : pd.DataFrame
         Meta data for a single location.
     tilt : float, optional
-        Tilt angle of PV system relative to horizontal.
+        Tilt angle of PV system relative to horizontal. [°]
     azimuth : float, optional
-        Azimuth angle of PV system relative to north.
+        Azimuth angle of PV system relative to north. [°]
     sky_model : str, optional
         Options: 'isotropic', 'klucher', 'haydavies', 'reindl', 'king', 'perez'.
     temp_model : str, optional
         Options: 'sapm'.  'pvsyst' and 'faiman' will be added later.
+        Performs the calculations for the cell temperature.
     conf_0 : str, optional
+        Model for the high temperature module on the exponential decay curve.
         Default: 'insulated_back_glass_polymer'
     conf_inf : str, optional
+        Model for the lowest temperature module on the exponential decay curve.
         Default: 'open_rack_glass_polymer'
     x0 : float, optional
         Thermal decay constant (cm), [Kempe, PVSC Proceedings 2023]
@@ -208,14 +233,19 @@ def standoff(
         Effective gap "x" for the lower limit for Level 1 or Level 0 modules (IEC TS 63216)
     T98_0 : float [°C]
         This is the 98th percential temperature of a theoretical module with no standoff.
-     T98_inf : float [°C]
+    T98_inf : float [°C]
         This is the 98th percential temperature of a theoretical rack mounted module.
         
     References
     ----------
     M. Kempe, et al. Close Roof Mounted System Temperature Estimation for Compliance
     to IEC TS 63126, PVSC Proceedings 2023
     """
+    if azimuth == None: #Sets the default orientation to equator facing.
+        if float(meta['latitude']) < 0:
+            azimuth=0
+        else:
+            azimuth=180
 
     parameters = ["temp_air", "wind_speed", "dhi", "ghi", "dni"]
 
@@ -229,17 +259,17 @@ def standoff(
 
     solar_position = spectral.solar_position(weather_df, meta)
     poa = spectral.poa_irradiance(
-        weather_df,
-        meta,
+        weather_df=weather_df,
+        meta=meta,
         sol_position=solar_position,
         tilt=tilt,
         azimuth=azimuth,
         sky_model=sky_model, )
-    T_0 = temperature.module(
-        weather_df, meta, poa, temp_model, conf_0, wind_speed_factor )
+    T_0 = temperature.cell(
+        weather_df=weather_df, meta=meta, poa=poa, temp_model=temp_model, conf=conf_0, wind_speed_factor=wind_speed_factor )
     T98_0 = T_0.quantile(q=0.98, interpolation="linear")
-    T_inf = temperature.module(
-        weather_df, meta, poa, temp_model, conf_inf, wind_speed_factor )
+    T_inf = temperature.cell(
+        weather_df=weather_df, meta=meta, poa=poa, temp_model=temp_model, conf=conf_inf, wind_speed_factor=wind_speed_factor )
     T98_inf = T_inf.quantile(q=0.98, interpolation="linear")
 
     try:
@@ -265,8 +295,10 @@ def T98_estimate(
     conf_0="insulated_back_glass_polymer",
     conf_inf="open_rack_glass_polymer",
     wind_speed_factor=1.7,
+    tilt=0,
+    azimuth=None,
     x_eff=None,
-    x_0=6.5):
+    x_0=6.5,):
 
     """
     Calculate and set up data necessary to calculate the effective standoff distance for rooftop mounded PV system 
@@ -276,24 +308,27 @@ def T98_estimate(
     Parameters
     ----------
     x_eff : float
-        This is the effective module standoff distance according to the model.
+        This is the effective module standoff distance according to the model. [cm]
     x_0 : float, optional
-        Thermal decay constant [cm],
+        Thermal decay constant. [cm]
     weather_df : pd.DataFrame
-        Weather data for a single location.
+        Weather data for a single location. 
     meta : pd.DataFrame
         Meta data for a single location.
     tilt : float, 
-        Tilt angle of PV system relative to horizontal. 
+        Tilt angle of PV system relative to horizontal. [°]
     azimuth : float, optional
-        Azimuth angle of PV system relative to north.
+        Azimuth angle of PV system relative to north. [°]
     sky_model : str, optional
         Options: 'isotropic', 'klucher', 'haydavies', 'reindl', 'king', 'perez'.
     temp_model : str, optional
         Options: 'sapm'.  'pvsyst' and 'faiman' will be added later.
+        Performs the calculations for the cell temperature.
     conf_0 : str, optional
+        Model for the high temperature module on the exponential decay curve.
         Default: 'insulated_back_glass_polymer'
     conf_inf : str, optional
+        Model for the lowest temperature module on the exponential decay curve.
         Default: 'open_rack_glass_polymer'
     wind_speed_factor : float, optional
         Wind speed correction factor to account for different wind speed measurement heights
@@ -308,8 +343,13 @@ def T98_estimate(
         This is the 98th percential temperature for the module at the given tilt, azimuth, and x_eff.
 
     """
+    if azimuth == None: #Sets the default orientation to equator facing.
+        if float(meta['latitude']) < 0:
+            azimuth=0
+        else:
+            azimuth=180
 
-    parameters = ["temp_air", "wind_speed", "dhi", "ghi", "dni", "temp_measured"]
+    parameters = ["temp_air", "wind_speed", "dhi", "ghi", "dni"]
 
     if isinstance(weather_df, dd.DataFrame):
         weather_df = weather_df[parameters].compute()
@@ -321,89 +361,23 @@ def T98_estimate(
 
     solar_position = spectral.solar_position(weather_df, meta)
     poa = spectral.poa_irradiance(
-        weather_df,
-        meta,
+        weather_df=weather_df,
+        meta=meta,
         sol_position=solar_position,
-        tilt=meta.tilt,
-        azimuth=meta.azimuth,
+        tilt=tilt,
+        azimuth=azimuth,
         sky_model=sky_model, )
-    T_0 = temperature.module(
-        weather_df, meta, poa, temp_model, conf_0, wind_speed_factor )
+    T_0 = temperature.cell(
+        weather_df, meta, poa, temp_model, conf_0, wind_speed_factor, )
     T98_0 = T_0.quantile(q=0.98, interpolation="linear")
-    T_inf = temperature.module(
-        weather_df, meta, poa, temp_model, conf_inf, wind_speed_factor )
+    T_inf = temperature.cell(
+        weather_df, meta, poa, temp_model, conf_inf, wind_speed_factor, )
     T98_inf = T_inf.quantile(q=0.98, interpolation="linear")
 
-    T98 = T_0 - (T_0-T_inf)*(1-np.exp(-x_eff/x_0))
+    T98 = T98_0 - (T98_0-T98_inf)*(1-np.exp(-x_eff/x_0))
 
     return T98
 
-def standoff_tilt_azimuth_scan(
-    weather_df=None,
-    meta=None,
-    weather_kwarg=None,
-    tilt_count=18,
-    azimuth_count=72,
-    sky_model="isotropic",
-    temp_model="sapm",
-    conf_0="insulated_back_glass_polymer",
-    conf_inf="open_rack_glass_polymer",
-    T98=70, # [°C]
-    x_0=6.5, # [cm]
-    wind_speed_factor=1.7):
-
-    """
-    Calculate a minimum standoff distance for roof mounded PV systems as a function of tilt and azimuth.
-
-    Parameters
-    ----------
-    weather_df : pd.DataFrame
-        Weather data for a single location.
-    meta : pd.DataFrame
-        Meta data for a single location.
-    tilt_count : integer
-        Step in degrees of change in tilt angle of PV system between calculations.
-    azimuth_count : integer
-        Step in degrees of change in Azimuth angle of PV system relative to north.
-    sky_model : str, optional
-        Options: 'isotropic', 'klucher', 'haydavies', 'reindl', 'king', 'perez'.
-    temp_model : str, optional
-        Options: 'sapm'.  'pvsyst' and 'faiman' will be added later.
-    conf_0 : str, optional
-        Default: 'insulated_back_glass_polymer'
-    conf_inf : str, optional
-        Default: 'open_rack_glass_polymer'
-    x_0 : float, optional
-        Thermal decay constant [cm], [Kempe, PVSC Proceedings 2023]
-    wind_speed_factor : float, optional
-        Wind speed correction factor to account for different wind speed measurement heights
-        between weather database (e.g. NSRDB) and the tempeature model (e.g. SAPM)
-        The NSRD provides calculations at 2m (i.e module height) but SAPM uses a 10m height.
-        It is recommended that a power-law relationship between height and wind speed of 0.33 be used.
-        This results in a wind_speed_factor of 1.7. It is acknowledged that this can vary significantly. 
-    Returns
-        standoff_series : 2-D array with each row consiting of tilt, azimuth, then standoff
-    """
-    
-    standoff_series=np.array([(azimuth_count+1)*(tilt_count+1)][3])
-    for x in range (0, azimuth_count+1):
-        for y in range (0,tilt_count+1):
-            standoff_series[x+y][0]=azimuth_count*180/azimuth_count
-            standoff_series[x+y][1]=tilt_count*90/azimuth_count
-            standoff_series[x+y][2]=standards.standoff(
-                weather_df=weather_df, 
-                meta=meta,
-                T98=T98,
-                tilt=y*90/tilt_count,
-                azimuth=x*180/azimuth_count,
-                sky_model=sky_model,
-                temp_model=temp_model,
-                conf_0=conf_0,
-                conf_inf=conf_inf,
-                x_0=x_0,
-                wind_speed_factor=wind_speed_factor)
-            
-    return standoff_series
 
 # def run_calc_standoff(
 #     project_points,