Canada
With a population of approximately 21,000, a very cold climate and without the adoption of the BC Energy Step Code, many would not expect the City of Fort St. John to have a high profile in the green building industry. Yet, it has carved its own precedent-setting path when it comes to green buildings.
Soon after a smaller Single-Family House project was completed, construction of a much larger Passive House project began nearby. The Fort St. John 50-unit Passive House affordable housing building originated from a partnership between BC Housing and BC Hydro. Upon completion in 2019, it became Canada’s largest multi-family Passive House building and the northernmost multi-family Passive House project in the world. The majority of the building was allocated to accommodate BC Hydro’s employees working on the Site C Dam project. Once the Site C project is complete, all 50 units will be provided as affordable housing for low and moderate-income households.
Of particular note is the fact that the building is all-electric (not connected to a gas supply). This was a key decision, made early in the development process, that bestows an incredibly low GHGI on the building. The Province’s upcoming Zero Carbon Step Code (in effect as of May 1, 2023) defines this level of GHGI as zero-carbon ready and is likely to make it a minimum requirement by 2030. This building is not only living proof that future GHGI requirements can be met today but, like many other high-performance buildings in Fort St. John, it dispels the myth that gas-fired equipment is a necessity in northern climates.
Lessons learned
- When the primary HVAC need is cooling, then solar heat gains need to be minimized
Key facts
| Building | Heat Pump and Source | ||
| Location | Fort St. John, Canada | Operation mode | monoenergetic |
| Construction | 2019 | Heat source (SH) | ground |
| Heated area | 4510 m² | Heat source (DHW) | air |
| No. of apartments | 50 | ||
| Level of insulation | good | ||
| Heating sytem | Domestic Hot Water | ||
| Thermal energy use intensity | 16.9 kWh/m2 per year | Hybrid device | Electric resistance water heater |
| Annual cooling demand | 22.5 kWh/m2 per year | ||
| Other information | |||
| Climate Zone | Dfb | Refrigerant | R410A |
| Boreholes | 35 vertical | Greenhouse Gas Intensity | 0.19 kg CO2eq/m2yr |
Description of the technical concept
Space Heating:
The building relies on Daikin VRV T-Series water-cooled heat recovery units (RWEQ series) for both space heating and cooling. The heat recovery units are connected to a geo-exchange field with 35 vertical boreholes located under the staff parking area on the northwest side of the building.
Airtight buildings require mechanical ventilation. To achieve this, the engineering team specified a Tempeff DualCore® energy recovery ventilator (ERV) with a highly efficient sensible and latent heat recovery capacity (90% and 70%, respectively). The ERV has two heat exchangers and by regularly alternating the airflow across the heat exchangers, the ERV is able to operate without a bypass mode, defrost cycle or preheating of outdoor air – even at extremely low temperatures. This feature makes this cold-climate ERV significantly more energy-efficient than most others over its entire operational range.
The building is in operation 24/7, therefore its internal heat gains (lighting, electrical loads, body heat, etc.) are high, resulting in a higher annual cooling load than heating load.
This is uncommon for most buildings of this size in northern climate zones. Because the cooling load is dominant, it was important to minimize solar heat gains for most of the year. This was achieved by specifying a low solar heat gain coefficient for the glazing (0.3), a large brise-soleil on the south elevation and a low window-to-wall ratio on the east, west and north elevations.
Domestic Hot Water:
To generate domestic hot water, the engineering team specified Rheem hybrid electric water heaters which combine a heat pump with an electric resistance water heater.
CA006 – Zero Carbon and Net Zero Energy-Ready
Case study delivered by: Zero Emissions Innovation Centre (ZEIC) Zero Carbon and Net Zero Energy-Ready in Northern BC – ZEBx