add initial fast solver implementation 🤞

Cargo.toml

@@ -9,6 +9,7 @@ edition = "2021"
 clap = { version = "4.3.10", features = ["derive"] }
 csv = "1.2.2"
 itertools = "0.11.0"
+nalgebra = "0.32.3"
 rstest = "0.17.0"
 serde = { version = "1.0.164", features = ["derive"] }
 serde_json = "1.0.100"

src/core/space_heat_demand/building_element.rs

@@ -0,0 +1,105 @@
+use crate::input::{BuildingElement, MassDistributionClass};
+
+pub fn area_for_building_element_input(element: &BuildingElement) -> f64 {
+    match element {
+        &BuildingElement::Opaque { area: a, .. } => a,
+        &BuildingElement::Transparent { area: a, .. } => match a {
+            Some(a) => a,
+            None => 0.0, // just to give some nominal value
+        },
+        &BuildingElement::Ground { area: a, .. } => a,
+        &BuildingElement::AdjacentZTC { area: a, .. } => a,
+        &BuildingElement::AdjacentZTUSimple { area: a, .. } => a,
+    }
+}
+
+/// Calculate the number of nodes for a building element
+/// (this is a shortcut to properly implementing building elements!)
+pub fn number_of_building_element_nodes(element: &BuildingElement) -> u32 {
+    let k_pli = match element {
+        &BuildingElement::Opaque {
+            mass_distribution_class: ref dist_class,
+            ref k_m,
+            ..
+        } => match dist_class {
+            MassDistributionClass::I => vec![0.0, 0.0, 0.0, 0.0, *k_m],
+            MassDistributionClass::E => vec![*k_m, 0.0, 0.0, 0.0, 0.0],
+            MassDistributionClass::IE => {
+                let k_ie = k_m / 2.0;
+                vec![k_ie, 0.0, 0.0, 0.0, k_ie]
+            }
+            MassDistributionClass::D => {
+                let k_inner = *k_m / 4.0;
+                let k_outer = *k_m / 8.0;
+                vec![k_outer, k_inner, k_inner, k_inner, k_outer]
+            }
+            MassDistributionClass::M => vec![0.0, 0.0, *k_m, 0.0, 0.0],
+        },
+        &BuildingElement::AdjacentZTC {
+            mass_distribution_class: ref dist_class,
+            ref k_m,
+            ..
+        } => match dist_class {
+            MassDistributionClass::I => vec![0.0, 0.0, 0.0, 0.0, *k_m],
+            MassDistributionClass::E => vec![*k_m, 0.0, 0.0, 0.0, 0.0],
+            MassDistributionClass::IE => {
+                let k_ie = *k_m / 2.0;
+                vec![k_ie, 0.0, 0.0, 0.0, k_ie]
+            }
+            MassDistributionClass::D => {
+                let k_inner = *k_m / 4.0;
+                let k_outer = *k_m / 8.0;
+                vec![k_outer, k_inner, k_inner, k_inner, k_outer]
+            }
+            MassDistributionClass::M => vec![0.0, 0.0, *k_m, 0.0, 0.0],
+        },
+        &BuildingElement::AdjacentZTUSimple {
+            mass_distribution_class: ref dist_class,
+            ref k_m,
+            ..
+        } => match dist_class {
+            MassDistributionClass::I => vec![0.0, 0.0, 0.0, 0.0, *k_m],
+            MassDistributionClass::E => vec![*k_m, 0.0, 0.0, 0.0, 0.0],
+            MassDistributionClass::IE => {
+                let k_ie = k_m / 2.0;
+                vec![k_ie, 0.0, 0.0, 0.0, k_ie]
+            }
+            MassDistributionClass::D => {
+                let k_inner = *k_m / 4.0;
+                let k_outer = *k_m / 8.0;
+                vec![k_outer, k_inner, k_inner, k_inner, k_outer]
+            }
+            MassDistributionClass::M => vec![0.0, 0.0, *k_m, 0.0, 0.0],
+        },
+        &BuildingElement::Ground {
+            mass_distribution_class: ref dist_class,
+            ref k_m,
+            ..
+        } => {
+            let k_gr = THICKNESS_GROUND_LAYER * HEAT_CAPACITY_PER_VOLUME_OF_GROUND;
+            match dist_class {
+                MassDistributionClass::I => vec![0.0, k_gr, 0.0, 0.0, *k_m],
+                MassDistributionClass::E => vec![0.0, k_gr, *k_m, 0.0, 0.0],
+                MassDistributionClass::IE => {
+                    let k_ie = *k_m / 2.0;
+                    vec![0.0, k_gr, k_ie, 0.0, k_ie]
+                }
+                MassDistributionClass::D => {
+                    let k_inner = *k_m / 2.0;
+                    let k_outer = *k_m / 4.0;
+                    vec![0.0, k_gr, k_outer, k_inner, k_outer]
+                }
+                MassDistributionClass::M => vec![0.0, k_gr, 0.0, *k_m, 0.0],
+            }
+        }
+        &BuildingElement::Transparent { .. } => vec![0.0, 0.0],
+    };
+
+    k_pli.len() as u32
+}
+
+// # Thermal properties of ground from BS EN ISO 13370:2017 Table 7
+// # Use values for clay or silt (same as BR 443 and SAP 10)
+const THERMAL_CONDUCTIVITY_OF_GROUND: f64 = 1.5; // in W/(m.K)
+const HEAT_CAPACITY_PER_VOLUME_OF_GROUND: f64 = 3000000.0; // in J/(m3.K)
+const THICKNESS_GROUND_LAYER: f64 = 0.5; // in m. Specified in BS EN ISO 52016-1:2017 section 6.5.8.2

src/core/space_heat_demand/mod.rs

@@ -1,2 +1,4 @@
+mod building_element;
+mod thermal_bridge;
 mod ventilation_element;
 pub mod zone;