implementing loft insulation wip

recommendations/RoofRecommendations.py

@@ -0,0 +1,134 @@
+import math
+from backend import Property
+from typing import List
+from datatypes.enums import QuantityUnits
+from recommendations.recommendation_utils import (
+    get_roof_u_value, r_value_per_mm_to_u_value, calculate_u_value_uplift, is_diminishing_returns,
+    update_lowest_selected_u_value, get_recommended_part
+)
+
+
+class RoofRecommendations:
+    # part L building regulations indicate that any rennovations on an existing property's roof should
+    # achieve a U-value of no higher than 0.16
+    # This can be seen in table 4.3 in building regulations part L:
+    # https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1133079
+    # /Approved_Document_L__Conservation_of_fuel_and_power__Volume_1_Dwellings__2021_edition_incorporating_2023_amendments.pdf
+    BUILDING_REGULATIONS_PART_L_MAX_U_VALUE = 0.16
+
+    DIMINISHING_RETURNS_U_VALUE = 0.14
+
+    def __init__(
+        self,
+        property_instance: Property,
+        materials: List
+    ):
+        self.property = property_instance
+        # For audit purposes, when estimating u values we'll store it
+        self.estimated_u_value = None
+
+        # Will contains a list of recommended measures
+        self.recommendations = []
+
+        self.materials = materials
+
+    def recommend(self):
+        u_value = self.property.roof["thermal_transmittance"]
+
+        insulation_thickness = self.property.walls["insulation_thickness"]
+
+        # We check if the roof is already insulated and if so, we exit
+        if insulation_thickness in ["average", "above average"]:
+            return
+
+        # If we have a u-value already, need to implement this
+        if u_value:
+            raise NotImplementedError("Implement me")
+
+        u_value = get_roof_u_value(**{**self.property.roof, "age_band": self.property.age_band})
+
+        # With loft insulation, 100mm goes between the joists and the rest is rolled on top
+        # Therefore the price is 100mm + whatever thickness is rolled on top, rolled at a 90 degree angle
+        # from the base layer
+        materials = [
+            {
+                'id': 4,
+                'type': 'loft_insulation',
+                'description': 'Iso Spacesaver Mineral Wool insulation',
+                'depths': [270, 300],
+                'depth_unit': 'mm',
+                'cost': [9, 10],
+                'cost_unit': 'gbp_sq_meter',
+                'r_value_per_mm': 0.022727272727272728,
+                'r_value_unit': 'square_meter_kelvin_per_watt',
+                'thermal_conductivity': 0.044,
+                'thermal_conductivity_unit': 'watt_per_meter_kelvin',
+                'link': "https://flooringwarehousedirect.co.uk/product/isover-spacesaver-roll-100mm-x-1160mm-x-12-18m"
+                        "-14-13m2/",
+                'is_active': True
+            },
+        ]
+
+        self.materials = materials
+
+        if self.property.roof["is_pitched"]:
+            # We recommend loft insulation
+            self.recommend_loft_insulation(u_value)
+            return
+
+    def recommend_loft_insulation(self, u_value):
+
+        """
+        This method will recommend which insulation materials to use
+        :return:
+        """
+
+        loft_insulation_materials = [m for m in self.materials if m["type"] == "loft_insulation"]
+
+        lowest_selected_u_value = None
+        recommendations = []
+        for material in loft_insulation_materials:
+
+            for depth, cost_per_unit in zip(material["depths"], material["cost"]):
+
+                part_u_value = r_value_per_mm_to_u_value(depth, material["r_value_per_mm"])
+
+                _, new_u_value = calculate_u_value_uplift(u_value, part_u_value)
+                new_u_value = math.ceil(new_u_value * 100.0) / 100.0
+
+                # If I have a lowest U value and my new u value is higher than that but lower than the
+                # diminishing returns threshold, it can be considered
+
+                # If I have a lowest U value and my new u value is lower than the lowest value, it's
+                # further into the diminishing returns threshold and can shouldn't be
+
+                if is_diminishing_returns(
+                    recommendations, new_u_value, lowest_selected_u_value, self.DIMINISHING_RETURNS_U_VALUE
+                ):
+                    continue
+
+                # We allow a small tolerance for error so we don't discount the recommendation entirely
+                if new_u_value <= self.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE:
+                    lowest_selected_u_value = update_lowest_selected_u_value(lowest_selected_u_value, new_u_value)
+
+                    estimated_cost = cost_per_unit * self.property.insulation_wall_area
+
+                    recommendations.append(
+                        {
+                            "parts": [
+                                get_recommended_part(
+                                    part=material,
+                                    selected_depth=depth,
+                                    quantity=self.property.insulation_wall_area,
+                                    quantity_unit=QuantityUnits.m2.value,
+                                    selected_total_cost=estimated_cost
+                                )
+                            ],
+                            "type": "roof_insulation",
+                            "description": "TODO ",
+                            "starting_u_value": u_value,
+                            "new_u_value": new_u_value,
+                            "sap_points": None,
+                            "cost": estimated_cost,
+                        }
+                    )

recommendations/WallRecommendations.py

@@ -23,11 +23,17 @@ class WallRecommendations(Definitions):
 
     # part L building regulations indicate that any rennovations on an existing property's walls should
     # achieve a U-value of no higher than 0.3
+    # This can be seen in table 4.3 in building regulations part L:
+    # https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1133079
+    # /Approved_Document_L__Conservation_of_fuel_and_power__Volume_1_Dwellings__2021_edition_incorporating_2023_amendments.pdf
     BUILDING_REGULATIONS_PART_L_MAX_U_VALUE = 0.3
     # We don't recommend measures that are too low because it becomes expensive, therefore we aim to avoid
     # diminishing returns. This value should be verified with Osmosis (TODO)
     DIMINISHING_RETURNS_U_VALUE = 0.25
 
+    # Building regulations part L also indicates that cavity wall insulation should result in 0.55 u-value
+    BUILDING_REGULATIONS_PART_L_CAVITY_WALL_MAX_U_VALUE = 0.55
+
     # Part L regulations indicate that any new build should have walls that achieve a u-value of no higher
     # than 0.18.
     BUILDING_REGULATIONS_PART_L_NEW_BUILD_MAX_U_VALUE = 0.18
@@ -167,29 +173,30 @@ class WallRecommendations(Definitions):
             ):
                 continue
 
-            lowest_selected_u_value = update_lowest_selected_u_value(lowest_selected_u_value, new_u_value)
+            if new_u_value <= self.BUILDING_REGULATIONS_PART_L_CAVITY_WALL_MAX_U_VALUE:
+                lowest_selected_u_value = update_lowest_selected_u_value(lowest_selected_u_value, new_u_value)
 
-            estimated_cost = part["cost"] * self.property.insulation_wall_area
+                estimated_cost = part["cost"] * self.property.insulation_wall_area
 
-            recommendations.append(
-                {
-                    "parts": [
-                        get_recommended_part(
-                            part=part,
-                            selected_depth=None,
-                            quantity=self.property.insulation_wall_area,
-                            quantity_unit=QuantityUnits.m2.value,
-                            selected_total_cost=estimated_cost
-                        )
-                    ],
-                    "type": "wall_insulation",
-                    "description": f"Fill cavity with {part['description']}",
-                    "starting_u_value": u_value,
-                    "new_u_value": new_u_value,
-                    "sap_points": None,
-                    "cost": estimated_cost,
-                }
-            )
+                recommendations.append(
+                    {
+                        "parts": [
+                            get_recommended_part(
+                                part=part,
+                                selected_depth=None,
+                                quantity=self.property.insulation_wall_area,
+                                quantity_unit=QuantityUnits.m2.value,
+                                selected_total_cost=estimated_cost
+                            )
+                        ],
+                        "type": "wall_insulation",
+                        "description": f"Fill cavity with {part['description']}",
+                        "starting_u_value": u_value,
+                        "new_u_value": new_u_value,
+                        "sap_points": None,
+                        "cost": estimated_cost,
+                    }
+                )
 
         self.recommendations = recommendations
 

recommendations/recommendation_utils.py

@@ -517,3 +517,20 @@ def estimate_wall_area(num_floors, floor_height, perimeter):
     total_wall_area = wall_area_one_floor * num_floors
 
     return total_wall_area
+
+
+def calculate_r_value_per_mm(thickness_mm, thermal_conductivity_w_mK):
+    """
+    # Calculate R-value (thermal resistance) using the formula: R = thickness / thermal_conductivity
+    # Note: The thickness should be converted to meters for the units to be consistent.
+    :param thickness_mm:
+    :param thermal_conductivity_w_mK:
+    :return:
+    """
+
+    r_value_m2k_w = (thickness_mm / 1000) / thermal_conductivity_w_mK
+
+    # Calculate R-value per mm
+    r_value_per_mm = r_value_m2k_w / thickness_mm
+
+    return r_value_per_mm