Building energy simulation and analysis for construction. Calculate heating/cooling loads, evaluate envelope performance, optimize HVAC sizing, and ensure energy code compliance.
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:
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")
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_sol_air_correction(wall['orientation'])
transmission_gain += wall['area'] * u_value * sol_air_delta
# Window solar gains
solar_gain = 0
for window in self.building.windows:
if window['zone'] == zone.zone_id:
shgc = window['window_type'].shgc
irradiance = self._get_solar_irradiance(window['orientation'])
solar_gain += window['area'] * shgc * irradiance
# Window conduction
window_conduction = 0
for window in self.building.windows:
if window['zone'] == zone.zone_id:
window_conduction += window['area'] * window['window_type'].u_value * delta_t
# Internal gains
lighting_gain = zone.floor_area_m2 * zone.lighting_power_density
equipment_gain = zone.floor_area_m2 * zone.equipment_power_density
people_gain = zone.occupancy * 75 # W per person sensible
# Ventilation
ventilation_gain = zone.occupancy * zone.ventilation_rate * 1.2 * delta_t
total = (transmission_gain + solar_gain + window_conduction +
lighting_gain + equipment_gain + people_gain + ventilation_gain)
results[zone.zone_id] = {
'zone_name': zone.name,
'transmission_gain_w': transmission_gain,
'solar_gain_w': solar_gain,
'window_conduction_w': window_conduction,
'lighting_gain_w': lighting_gain,
'equipment_gain_w': equipment_gain,
'people_gain_w': people_gain,
'ventilation_gain_w': ventilation_gain,
'total_w': total,
'total_kw': total / 1000,
'w_per_m2': total / zone.floor_area_m2
}
return results
def _get_sol_air_correction(self, orientation: str) -> float:
"""Get sol-air temperature correction by orientation"""
corrections = {
'north': 0, 'south': 8, 'east': 4, 'west': 6,
'northeast': 2, 'northwest': 3, 'southeast': 6, 'southwest': 7
}
return corrections.get(orientation.lower(), 3)
def _get_solar_irradiance(self, orientation: str) -> float:
"""Get design solar irradiance W/m² by orientation"""
# Simplified peak values
irradiance = {
'north': 150, 'south': 450, 'east': 350, 'west': 350,
'northeast': 200, 'northwest': 200, 'southeast': 400, 'southwest': 400
}
return irradiance.get(orientation.lower(), 300)
class HVACSizer:
"""Size HVAC systems based on loads"""
def __init__(self, calculator: ThermalCalculator):
self.calculator = calculator
def size_heating_system(self, safety_factor: float = 1.15) -> Dict:
"""Size heating system"""
heating_loads = self.calculator.calculate_design_heating_load()
total_load = sum(z['total_kw'] for z in heating_loads.values())
sized_capacity = total_load * safety_factor
# Recommend system type
if sized_capacity < 15:
system_type = "Split system heat pump"
elif sized_capacity < 50:
system_type = "Packaged rooftop unit"
elif sized_capacity < 200:
system_type = "Central boiler with radiators"
else:
system_type = "Central plant with multiple boilers"
return {
'total_load_kw': total_load,
'sized_capacity_kw': sized_capacity,
'safety_factor': safety_factor,
'recommended_system': system_type,
'zone_loads': heating_loads
}
def size_cooling_system(self, safety_factor: float = 1.1) -> Dict:
"""Size cooling system"""
cooling_loads = self.calculator.calculate_design_cooling_load()
total_load = sum(z['total_kw'] for z in cooling_loads.values())
sized_capacity = total_load * safety_factor
# Convert to tons
capacity_tons = sized_capacity / 3.517
# Recommend system type
if capacity_tons < 5:
system_type = "Split system DX"
elif capacity_tons < 20:
system_type = "VRF system"
elif capacity_tons < 100:
system_type = "Chilled water with AHUs"
else:
system_type = "Central chiller plant"
return {
'total_load_kw': total_load,
'total_load_tons': capacity_tons,
'sized_capacity_kw': sized_capacity,
'sized_capacity_tons': capacity_tons * safety_factor,
'safety_factor': safety_factor,
'recommended_system': system_type,
'zone_loads': cooling_loads
}
def estimate_annual_energy(self) -> Dict:
"""Estimate annual energy consumption"""
climate = self.calculator.climate
heating_loads = self.calculator.calculate_design_heating_load()
cooling_loads = self.calculator.calculate_design_cooling_load()
total_heating_load = sum(z['total_kw'] for z in heating_loads.values())
total_cooling_load = sum(z['total_kw'] for z in cooling_loads.values())
# Simplified degree-day calculation
# Heating energy = load * HDD * 24 / delta_t_design
delta_t_heating = 21 - climate['design_winter']
heating_kwh = total_heating_load * climate['hdd'] * 24 / delta_t_heating / 1000
delta_t_cooling = climate['design_summer'] - 24
cooling_kwh = total_cooling_load * climate['cdd'] * 24 / delta_t_cooling / 1000 if delta_t_cooling > 0 else 0
# Apply efficiency factors
heating_fuel_efficiency = 0.9 # Gas boiler
cooling_cop = 3.5 # Chiller COP
heating_consumption = heating_kwh / heating_fuel_efficiency
cooling_consumption = cooling_kwh / cooling_cop
return {
'heating_load_kw': total_heating_load,
'cooling_load_kw': total_cooling_load,
'annual_heating_kwh': heating_kwh,
'annual_cooling_kwh': cooling_kwh,
'heating_fuel_kwh': heating_consumption,
'cooling_electricity_kwh': cooling_consumption,
'total_hvac_energy_kwh': heating_consumption + cooling_consumption
}
@dataclass
class EnergyCodeRequirements:
code_name: str
climate_zone: str
wall_u_max: float
roof_u_max: float
floor_u_max: float
window_u_max: float
window_shgc_max: float
lighting_lpd_max: float # W/m²
class ComplianceChecker:
"""Check energy code compliance"""
CODES = {
'ASHRAE_90.1_2019_4A': EnergyCodeRequirements(
code_name="ASHRAE 90.1-2019",
climate_zone="4A",
wall_u_max=0.45,
roof_u_max=0.27,
floor_u_max=0.32,
window_u_max=2.0,
window_shgc_max=0.40,
lighting_lpd_max=9.0
),
'IECC_2021_5A': EnergyCodeRequirements(
code_name="IECC 2021",
climate_zone="5A",
wall_u_max=0.35,
roof_u_max=0.20,
floor_u_max=0.30,
window_u_max=1.7,
window_shgc_max=0.40,
lighting_lpd_max=8.5
)
}
def __init__(self, code_key: str):
self.requirements = self.CODES.get(code_key)
if not self.requirements:
raise ValueError(f"Unknown code: {code_key}")
def check_envelope(self, building: BuildingGeometry) -> Dict:
"""Check envelope compliance"""
results = {
'code': self.requirements.code_name,
'climate_zone': self.requirements.climate_zone,
'compliant': True,
'issues': []
}
# Check walls
for wall in building.walls:
u_value = wall['assembly'].u_value
if u_value > self.requirements.wall_u_max:
results['compliant'] = False
results['issues'].append({
'element': f"Wall {wall['zone']} {wall['orientation']}",
'actual': u_value,
'required': self.requirements.wall_u_max,
'issue': 'Exceeds maximum U-value'
})
# Check windows
for window in building.windows:
u_value = window['window_type'].u_value
shgc = window['window_type'].shgc
if u_value > self.requirements.window_u_max:
results['compliant'] = False
results['issues'].append({
'element': f"Window {window['zone']} {window['orientation']}",
'actual': u_value,
'required': self.requirements.window_u_max,
'issue': 'Exceeds maximum U-value'
})
if shgc > self.requirements.window_shgc_max:
results['compliant'] = False
results['issues'].append({
'element': f"Window {window['zone']} {window['orientation']}",
'actual': shgc,
'required': self.requirements.window_shgc_max,
'issue': 'Exceeds maximum SHGC'
})
# Check roof
for roof in building.roofs:
u_value = roof['assembly'].u_value
if u_value > self.requirements.roof_u_max:
results['compliant'] = False
results['issues'].append({
'element': f"Roof {roof['zone']}",
'actual': u_value,
'required': self.requirements.roof_u_max,
'issue': 'Exceeds maximum U-value'
})
return results
def check_lighting(self, zones: List[Zone]) -> Dict:
"""Check lighting power density compliance"""
results = {
'compliant': True,
'issues': []
}
for zone in zones:
if zone.lighting_power_density > self.requirements.lighting_lpd_max:
results['compliant'] = False
results['issues'].append({
'zone': zone.name,
'actual_lpd': zone.lighting_power_density,
'required_max': self.requirements.lighting_lpd_max
})
return results
| Component | Good U-Value | Code Maximum |
|---|---|---|
| Wall | < 0.25 W/m²K | 0.35-0.45 |
| Roof | < 0.15 W/m²K | 0.20-0.27 |
| Floor | < 0.20 W/m²K | 0.25-0.32 |
| Window | < 1.2 W/m²K | 1.7-2.0 |
co2-estimation for carbon analysiscost-prediction for energy cost modelingbim-validation-pipeline for model integration