Energy Simulation

Overview

This skill implements building energy simulation and analysis. Calculate thermal loads, evaluate building envelope performance, and optimize systems for energy efficiency and code compliance.

Capabilities:

• Heating/cooling load calculations
• Envelope thermal analysis
• HVAC system sizing
• Energy code compliance
• Renewable energy integration
• Life cycle cost analysis

Quick Start

from dataclasses import dataclass, field
from typing import List, Dict, Optional, Tuple
from enum import Enum
import numpy as np

class WallType(Enum):
    CONCRETE = "concrete"
    BRICK = "brick"
    WOOD_FRAME = "wood_frame"
    STEEL_FRAME = "steel_frame"
    CURTAIN_WALL = "curtain_wall"

@dataclass
class BuildingEnvelope:
    wall_area_m2: float
    wall_u_value: float  # W/m²K
    roof_area_m2: float
    roof_u_value: float
    floor_area_m2: float
    floor_u_value: float
    window_area_m2: float
    window_u_value: float
    window_shgc: float  # Solar Heat Gain Coefficient

@dataclass
class ClimateData:
    location: str
    heating_degree_days: float  # HDD base 18°C
    cooling_degree_days: float  # CDD base 18°C
    design_temp_winter: float
    design_temp_summer: float

def calculate_heat_loss(envelope: BuildingEnvelope, climate: ClimateData,
                       indoor_temp: float = 21) -> float:
    """Calculate design heat loss (W)"""
    delta_t = indoor_temp - climate.design_temp_winter

    # Transmission losses
    wall_loss = envelope.wall_area_m2 * envelope.wall_u_value * delta_t
    roof_loss = envelope.roof_area_m2 * envelope.roof_u_value * delta_t
    floor_loss = envelope.floor_area_m2 * envelope.floor_u_value * delta_t * 0.5  # Ground factor
    window_loss = envelope.window_area_m2 * envelope.window_u_value * delta_t

    total_loss = wall_loss + roof_loss + floor_loss + window_loss

    # Add infiltration estimate (simplified)
    volume = envelope.floor_area_m2 * 3  # Assume 3m height
    infiltration = volume * 0.5 * 0.33 * delta_t  # 0.5 ACH, 0.33 Wh/m³K

    return total_loss + infiltration

# Example
envelope = BuildingEnvelope(
    wall_area_m2=500, wall_u_value=0.35,
    roof_area_m2=200, roof_u_value=0.25,
    floor_area_m2=200, floor_u_value=0.30,
    window_area_m2=100, window_u_value=1.4, window_shgc=0.4
)

climate = ClimateData(
    location="Moscow",
    heating_degree_days=5000,
    cooling_degree_days=300,
    design_temp_winter=-25,
    design_temp_summer=30
)

heat_loss = calculate_heat_loss(envelope, climate)
print(f"Design heat loss: {heat_loss/1000:.1f} kW")

Comprehensive Energy Analysis

Building Thermal Model

from dataclasses import dataclass, field
from typing import List, Dict, Optional, Tuple
from enum import Enum
import numpy as np
from datetime import datetime

@dataclass
class MaterialLayer:
    name: str
    thickness_m: float
    conductivity: float  # W/mK
    density: float  # kg/m³
    specific_heat: float  # J/kgK

    @property
    def resistance(self) -> float:
        """Thermal resistance R (m²K/W)"""
        return self.thickness_m / self.conductivity if self.conductivity > 0 else 0

@dataclass
class WallAssembly:
    name: str
    layers: List[MaterialLayer]
    inside_surface_resistance: float = 0.13  # m²K/W
    outside_surface_resistance: float = 0.04

    @property
    def total_resistance(self) -> float:
        return (self.inside_surface_resistance +
                sum(layer.resistance for layer in self.layers) +
                self.outside_surface_resistance)

    @property
    def u_value(self) -> float:
        return 1 / self.total_resistance if self.total_resistance > 0 else 0

@dataclass
class Window:
    name: str
    u_value: float
    shgc: float
    visible_transmittance: float = 0.6
    frame_fraction: float = 0.2

@dataclass
class Zone:
    zone_id: str
    name: str
    floor_area_m2: float
    volume_m3: float
    occupancy: int
    lighting_power_density: float  # W/m²
    equipment_power_density: float  # W/m²
    ventilation_rate: float  # L/s per person
    setpoint_heating: float = 21
    setpoint_cooling: float = 24

@dataclass
class BuildingGeometry:
    zones: List[Zone]
    walls: List[Dict]  # {zone, orientation, area, assembly}
    windows: List[Dict]  # {zone, orientation, area, window_type}
    roofs: List[Dict]  # {zone, area, assembly}
    floors: List[Dict]  # {zone, area, assembly, is_ground}

class ThermalCalculator:
    """Calculate building thermal loads"""

    # Standard climate data (simplified)
    CLIMATE_DB = {
        'moscow': {
            'hdd': 5000, 'cdd': 300,
            'design_winter': -25, 'design_summer': 30,
            'latitude': 55.75
        },
        'new_york': {
            'hdd': 2500, 'cdd': 800,
            'design_winter': -12, 'design_summer': 33,
            'latitude': 40.71
        },
        'dubai': {
            'hdd': 50, 'cdd': 3000,
            'design_winter': 15, 'design_summer': 45,
            'latitude': 25.20
        }
    }

    def __init__(self, building: BuildingGeometry, location: str):
        self.building = building
        self.location = location.lower()
        self.climate = self.CLIMATE_DB.get(self.location, self.CLIMATE_DB['moscow'])

    def calculate_design_heating_load(self) -> Dict:
        """Calculate design heating load for each zone"""
        delta_t = 21 - self.climate['design_winter']
        results = {}

        for zone in self.building.zones:
            # Transmission losses
            wall_loss = 0
            window_loss = 0
            roof_loss = 0
            floor_loss = 0

            for wall in self.building.walls:
                if wall['zone'] == zone.zone_id:
                    u_value = wall['assembly'].u_value
                    wall_loss += wall['area'] * u_value * delta_t

            for window in self.building.windows:
                if window['zone'] == zone.zone_id:
                    window_loss += window['area'] * window['window_type'].u_value * delta_t

            for roof in self.building.roofs:
                if roof['zone'] == zone.zone_id:
                    u_value = roof['assembly'].u_value
                    roof_loss += roof['area'] * u_value * delta_t

            for floor in self.building.floors:
                if floor['zone'] == zone.zone_id:
                    u_value = floor['assembly'].u_value
                    factor = 0.5 if floor.get('is_ground', False) else 1.0
                    floor_loss += floor['area'] * u_value * delta_t * factor

            # Infiltration
            infiltration_loss = zone.volume_m3 * 0.5 * 0.33 * delta_t

            # Ventilation (if mechanical)
            ventilation_loss = zone.occupancy * zone.ventilation_rate * 1.2 * delta_t

            total = wall_loss + window_loss + roof_loss + floor_loss + infiltration_loss + ventilation_loss

            results[zone.zone_id] = {
                'zone_name': zone.name,
                'wall_loss_w': wall_loss,
                'window_loss_w': window_loss,
                'roof_loss_w': roof_loss,
                'floor_loss_w': floor_loss,
                'infiltration_w': infiltration_loss,
                'ventilation_w': ventilation_loss,
                'total_w': total,
                'total_kw': total / 1000,
                'w_per_m2': total / zone.floor_area_m2
            }

        return results

    def calculate_design_cooling_load(self) -> Dict:
        """Calculate design cooling load for each zone"""
        delta_t = self.climate['design_summer'] - 24
        results = {}

        for zone in self.building.zones:
            # Transmission gains
            transmission_gain = 0
            for wall in self.building.walls:
                if wall['zone'] == zone.zone_id:
                    u_value = wall['assembly'].u_value
                    # Apply sol-air temperature correction for orientation
                    sol_air_delta = delta_t + self._get_so