Heat generators

IFC has no heat-pump class: heat pumps are usually exported as IfcUnitaryEquipment, which ifctrano recognises from their type, name or classification (see How ifctrano works). When the model does not say which kind of generator it contains, it can be given explicitly. This example heats ExampleHOM with the heating model of the heating tutorial, first with its gas boiler, then with an air-to-water heat pump on the same circuits.

from pathlib import Path

from ifctrano.building import Building
from ifctrano.hvac import HeatingOptions, ProductionKind

building = Building.from_ifc(
    Path("ExampleHOM.ifc"),
    hvac_file_paths=[Path("ExampleHOM_heating.ifc")],
    heating_options=HeatingOptions(heat_generator=ProductionKind.air_water_heat_pump),
)
building.save_model()

or, from the command line:

ifctrano create ExampleHOM.ifc --hvac ExampleHOM_heating.ifc --heat-generator air_water_heat_pump

Everything else (radiators, valves, circulators, mixing valves and their controls) is the same in both models.

Days 3 to 10 of the year (the first 2 simulated days are a warm-up and are left out).

Case	Zone	Mean [°C]	Minimum [°C]	Maximum [°C]	Radiator heat [kWh]	Peak radiator heat [kW]	Heat from the generator [kWh]	Gas [kWh]	Electricity [kWh]
Gas boiler	Mean of the zones	18.6	15.2	21.8	125	4.4	148	190
Air-to-water heat pump	Mean of the zones	18.6	15.2	21.8	125	2.8	124		36

What to expect. Both generators feed the same radiators, controlled to the same set points, so the rooms should be as warm in both cases. The difference is the energy bought: natural gas for the boiler, electricity for the heat pump, which takes most of its heat from the outdoor air.

What the simulation shows. Over days 3 to 10, the rooms are equally warm with both generators (18.6 °C on average, between the 15.85 °C setback and the 21 °C set point) and the radiators deliver the same 125 kWh. The boiler burns 190 kWh of natural gas to produce 148 kWh of heat; the heat pump produces 124 kWh from 36 kWh of electricity, a coefficient of performance of about 3.4 in these January days. The heat pump also loses less heat in the circuits (the generator heat is close to the heat of the radiators) and gives a lower peak at the morning reheat (2.8 kW against 4.4 kW).