Update utils/solar.py

utils/solar.py

@@ -4,7 +4,7 @@ import math
 from datetime import datetime
 from app.materials_library import MaterialLibrary, GlazingMaterial, Material
 from utils.ctf_calculations import ComponentType
-from app.m_c_data import DEFAULT_WINDOW_PROPERTIES  # Import for h_o default
+from app.m_c_data import DEFAULT_WINDOW_PROPERTIES
 import logging
 
 # Configure logging
@@ -67,45 +67,73 @@ class SolarCalculations:
         logger.info("Initialized SolarCalculations with MaterialLibrary and project-specific libraries.")
 
     @staticmethod
-    def day_of_year(month: int, day: int, year: int) -> int:
-        """Calculate day of the year (n) from month, day, and year, accounting for leap years.
+    def calculate_sky_temperature(T_out: float, dew_point: float, total_sky_cover: float = 0.5) -> float:
+        """Calculate sky temperature based on outdoor temperature, dew point, and cloud cover.
 
         Args:
-            month (int): Month of the year (1-12).
-            day (int): Day of the month (1-31).
-            year (int): Year.
+            T_out: Outdoor dry-bulb temperature (°C).
+            dew_point: Dew point temperature (°C).
+            total_sky_cover: Cloud cover fraction (0 to 1, default 0.5).
 
         Returns:
-            int: Day of the year (1-365 or 366 for leap years).
+            float: Sky temperature (°C).
 
         References:
-            ASHRAE Handbook—Fundamentals, Chapter 18.
+            ASHRAE Handbook—Fundamentals, Chapter 26.
         """
-        days_in_month = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
-        if year % 4 == 0 and (year % 100 != 0 or year % 400 == 0):
-            days_in_month[1] = 29
-        return sum(days_in_month[:month-1]) + day
+        epsilon_sky = 0.9 + 0.04 * total_sky_cover
+        T_sky = (epsilon_sky * (T_out + 273.15)**4)**0.25 - 273.15
+        return T_sky if dew_point <= T_out else dew_point
 
     @staticmethod
-    def equation_of_time(n: int) -> float:
-        """Calculate Equation of Time (EOT) in minutes using Spencer's formula.
+    def calculate_h_o(wind_speed: float, surface_type: ComponentType) -> float:
+        """Calculate outdoor convective heat transfer coefficient based on wind speed and surface type.
 
         Args:
-            n (int): Day of the year (1-365 or 366).
+            wind_speed: Wind speed (m/s).
+            surface_type: ComponentType enum (WALL, ROOF, FLOOR, WINDOW, SKYLIGHT).
 
         Returns:
-            float: Equation of Time in minutes.
+            float: Outdoor heat transfer coefficient (W/m²·K).
 
         References:
-            ASHRAE Handbook—Fundamentals, Chapter 18.
+            ASHRAE Handbook—Fundamentals, Chapter 26.
         """
-        B = (n - 1) * 360 / 365
-        B_rad = math.radians(B)
-        EOT = 229.2 * (0.000075 + 0.001868 * math.cos(B_rad) - 0.032077 * math.sin(B_rad) -
-                       0.014615 * math.cos(2 * B_rad) - 0.04089 * math.sin(2 * B_rad))
-        return EOT
+        wind_speed = max(min(wind_speed, 20.0), 0.0)  # Bound for stability
+        if surface_type in [ComponentType.WALL, ComponentType.FLOOR]:
+            h_o = 8.3 + 4.0 * (wind_speed ** 0.6)  # ASHRAE Ch. 26
+        elif surface_type == ComponentType.ROOF:
+            h_o = 9.1 + 2.8 * wind_speed  # ASHRAE Ch. 26
+        else:  # WINDOW, SKYLIGHT
+            h_o = DEFAULT_WINDOW_PROPERTIES["h_o"]
+        return max(h_o, 5.0)  # Minimum for stability
 
-    def get_surface_parameters(self, component: Any, building_info: Dict) -> Tuple[float, float, float, Optional[float], float]:
+    @staticmethod
+    def calculate_sol_air_temperature(T_out: float, I_t: float, absorptivity: float, emissivity: float, 
+                                     h_o: float, dew_point: float, total_sky_cover: float = 0.5) -> float:
+        """Calculate sol-air temperature for opaque surfaces.
+
+        Args:
+            T_out: Outdoor dry-bulb temperature (°C).
+            I_t: Total incident solar radiation (W/m²).
+            absorptivity: Surface absorptivity (0 to 1).
+            emissivity: Surface emissivity (0 to 1).
+            h_o: Outdoor convective heat transfer coefficient (W/m²·K).
+            dew_point: Dew point temperature (°C).
+            total_sky_cover: Cloud cover fraction (0 to 1, default 0.5).
+
+        Returns:
+            float: Sol-air temperature (°C).
+
+        References:
+            ASHRAE Handbook—Fundamentals, Chapter 26, Eq. 13.
+        """
+        sigma = 5.67e-8  # Stefan-Boltzmann constant
+        T_sky = SolarCalculations.calculate_sky_temperature(T_out, dew_point, total_sky_cover)
+        T_sol_air = T_out + (absorptivity * I_t - emissivity * sigma * ((T_out + 273.15)**4 - (T_sky + 273.15)**4)) / h_o
+        return T_sol_air
+
+    def get_surface_parameters(self, component: Any, building_info: Dict, wind_speed: float = 4.0) -> Tuple[float, float, float, Optional[float], float]:
         """
         Determine surface parameters (tilt, azimuth, h_o, emissivity, absorptivity) for a component.
         Uses pre-calculated values stored in the component dictionary from components.py.
@@ -113,7 +141,8 @@ class SolarCalculations:
         Args:
             component: Component dictionary with surface_tilt, surface_azimuth, absorptivity/emissivity or shgc,
                       component_type, and optionally fenestration.
-            building_info (Dict): Building information (not used since parameters are pre-calculated).
+            building_info: Building information (not used since parameters are pre-calculated).
+            wind_speed: Wind speed (m/s, default 4.0).
 
         Returns:
             Tuple[float, float, float, Optional[float], float]: Surface tilt (°), surface azimuth (°),
@@ -137,19 +166,18 @@ class SolarCalculations:
         }
         component_type = type_map.get(component_type, ComponentType.WALL)
 
+        # Calculate h_o dynamically
+        h_o = self.calculate_h_o(wind_speed, component_type)
+
         # Default parameters
         if component_type == ComponentType.ROOF:
             surface_tilt = component.get('surface_tilt', 0.0)
-            h_o = 23.0
         elif component_type == ComponentType.SKYLIGHT:
             surface_tilt = component.get('surface_tilt', 0.0)
-            h_o = component.get('h_o', DEFAULT_WINDOW_PROPERTIES["h_o"])
         elif component_type == ComponentType.FLOOR:
             surface_tilt = component.get('surface_tilt', 180.0)
-            h_o = 17.0
         else:  # WALL, WINDOW
             surface_tilt = component.get('surface_tilt', 90.0)
-            h_o = component.get('h_o', DEFAULT_WINDOW_PROPERTIES["h_o"]) if component_type == ComponentType.WINDOW else 17.0
 
         surface_azimuth = component.get('surface_azimuth', 0.0)
         emissivity = component.get('emissivity', 0.9 if component_type in [ComponentType.WALL, ComponentType.ROOF] else None)
@@ -176,19 +204,15 @@ class SolarCalculations:
             # Apply defaults
             if component_type == ComponentType.ROOF:
                 surface_tilt = 0.0
-                h_o = 23.0
                 surface_azimuth = 0.0
             elif component_type == ComponentType.SKYLIGHT:
                 surface_tilt = 0.0
-                h_o = DEFAULT_WINDOW_PROPERTIES["h_o"]
                 surface_azimuth = 0.0
             elif component_type == ComponentType.FLOOR:
                 surface_tilt = 180.0
-                h_o = 17.0
                 surface_azimuth = 0.0
             else:  # WALL, WINDOW
                 surface_tilt = 90.0
-                h_o = DEFAULT_WINDOW_PROPERTIES["h_o"] if component_type == ComponentType.WINDOW else 17.0
                 surface_azimuth = 0.0
 
             if component_type in [ComponentType.WALL, ComponentType.ROOF]:
@@ -237,7 +261,7 @@ class SolarCalculations:
         """Calculate solar angles, sol-air temperature, and solar heat gain for hourly data with GHI > 0.
 
         Args:
-            hourly_data (List[Dict]): Hourly weather data containing month, day, hour, GHI, DNI, DHI, dry_bulb.
+            hourly_data (List[Dict]): Hourly weather data containing month, day, szehour, GHI, DNI, DHI, dry_bulb.
             latitude (float): Latitude in degrees.
             longitude (float): Longitude in degrees.
             timezone (float): Timezone offset in hours.
@@ -294,6 +318,9 @@ class SolarCalculations:
             dni = record.get("direct_normal_radiation", ghi * 0.7)  # Fallback: estimate DNI
             dhi = record.get("diffuse_horizontal_radiation", ghi * 0.3)  # Fallback: estimate DHI
             outdoor_temp = record.get("dry_bulb")
+            dew_point = record.get("dew_point", outdoor_temp - 5.0)
+            wind_speed = record.get("wind_speed", 4.0)
+            total_sky_cover = record.get("total_sky_cover", 0.5)
             
             if None in [month, day, hour, outdoor_temp]:
                 logger.error(f"Missing required weather data for {month}/{day}/{hour}")
@@ -308,7 +335,8 @@ class SolarCalculations:
                 continue  # Skip hours with no solar radiation
 
             logger.info(f"Processing solar for {month}/{day}/{hour} with GHI={ghi}, DNI={dni}, DHI={dhi}, "
-                       f"dry_bulb={outdoor_temp}")
+                       f"dry_bulb={outdoor_temp}, dew_point={dew_point}, wind_speed={wind_speed}, "
+                       f"total_sky_cover={total_sky_cover}")
 
             # Step 2: Local Solar Time (LST) with Equation of Time
             n = self.day_of_year(month, day, year)
@@ -351,7 +379,7 @@ class SolarCalculations:
                     try:
                         # Get surface parameters
                         surface_tilt, surface_azimuth, h_o, emissivity, absorptivity = \
-                            self.get_surface_parameters(comp, building_info)
+                            self.get_surface_parameters(comp, building_info, wind_speed)
                         
                         # For windows/skylights, get SHGC from component
                         shgc = comp.get('shgc', 0.7)
@@ -382,11 +410,10 @@ class SolarCalculations:
 
                         # Calculate sol-air temperature for opaque surfaces
                         if comp.get('type', '').lower() in ['walls', 'roofs']:
-                            delta_R = 63.0 if comp.get('type', '').lower() == 'roofs' else 0.0
-                            sol_air_temp = outdoor_temp + (absorptivity * I_t - (emissivity or 0.9) * 
-                                                           delta_R) / h_o
-                            comp_result["sol_air_temp"] = round(sol_air_temp, 2)
-                            logger.info(f"Sol-air temp for {comp_result['component_id']} at {month}/{day}/{hour}: {sol_air_temp:.2f}°C")
+                            T_sol_air = self.calculate_sol_air_temperature(
+                                outdoor_temp, I_t, absorptivity, emissivity or 0.9, h_o, dew_point, total_sky_cover)
+                            comp_result["sol_air_temp"] = round(T_sol_air, 2)
+                            logger.info(f"Sol-air temp for {comp_result['component_id']} at {month}/{day}/{hour}: {T_sol_air:.2f}°C")
 
                         # Calculate solar heat gain for fenestration
                         elif comp.get('type', '').lower() in ['windows', 'skylights']: