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OSO, which means bear in Spanish, is a mixed-use development consisting of two buildings with commercial units on the ground floor and residential units above. Some small standalone amenity and commercial buildings are located between and behind the two larger buildings.
“OSO is exceptional because the construction details, mechanical design, and the equipment and materials used are all simple, readily available, and easy to put together. Vidorra’s goal is to have any contractor in Canada review the plans and specifications and easily understand them. For this development, there was no extra training required for any tradesperson on the job site. Every detail was familiar to them and part of their standard trade skill set. For widespread adoption of high-performance buildings, this approach is essential..” – Rod Nadeau, Co-owner, Vidorra Developments ltd.
A unique aspect of this building is the integration of the heating and cooling system with the ventilation system. This integrated system provides heating and cooling for both the units and the corridors. For a previous project, this mechanical design strategy has proven successful in keeping occupants comfortable during the June 2021 heat wave and the December 2021 cold snap.
Lessons learned
- Applying lessons learned from a previous high-performance building project is critical in achieving cost-effective results for developers, builders and the design team.
Key facts
| Building(s) | Heat Pump and Source | ||
| Location | Golden, Canada | Number of HP | 2 for SH 10 (DHW) |
| Construction | 2023 | Operation mode | monoenergetic |
| Heated area | 2250 m² | Heat source | air |
| No. of apartments | East: 30 West: 28 | Type of system | central |
| Level of insulation | good | Model | Mitsubishi City Multi (SH) SANCO2TM (DHW) |
| Heating sytem | Domestic Hot Water | ||
| Installed power | 1 x 35 kW 1 x 28 kW | Storage tanks | 3 x 454 l tank 1 x 454 l swing tank |
| Thermal energy use intensity | 7.7 kWh/m2 per year | Additional heating | tankless water heater (EL) |
| Annual cooling demand | 1.4 kWh/m2 per year | ||
| Return air temp. | 22°C (year-round) | ||
| Additional heating | Baseboard heaters (500W) in each flat | ||
| Other information | |||
| Climate Zone | Dfb | Refrigerant (SH) | R410A |
| Refrigerant (DHW) | CO2 | ||
Description of the technical concept
Space Heating and Cooling:
A 35kW (10-ton) and a 28kW (8-ton) Mitsubishi City Multi heat pump are connected to the Energy Recovery Ventilator’s (ERV) heating and cooling coil. The heat pumps use R410A refrigerant and can provide heating in outdoor temperatures as low as -25°C. The ERV includes a boost mode which doubles the airflow rate when more cooling (or heating) energy is required. The control strategy is to maintain the return air at 22°C year-round and use the ERV’s boost mode for additional cooling only.
If supplemental or back-up heating I required, the occupants can rely on a 500W electric baseboard heater installed in each room along the perimeter of the building. The ERV also has a (heat exchanger) bypass mode which allows it to to cool the units with outdoor air at night when the outdoor temperature is 2°C lower than the indoor temperature.
The ground-floor commercial units have mini-split heat pumps for backup heating and cooling. Their primary heating and cooling is supplied by the central ventilation system.
Domestic Hot Water:
Each building’s domestic hot water (DHW) system includes five SANCO2TM heat pump water heaters, three 454 l storage tanks and one 454 l swing tank connected to a 36kW Stiebel Eltroon tankless water heater. The swing tank, in combination with the tankless water heater, maintains the temperature of the hot water in the recirculation loop. Given the capacity of the tankless water heater, it also serves as a back-up water heater should there be an issue with the heat pump water heaters.
Four of the heat pumps are wall-mounted under the mechanical penthouse roof’s overhang and the fifth is installed inside the mechanical penthouse to keep the room cool and increase the efficiency of the HP (by providing it warmer ambient air).
CA005 – OSO
Case study delivered by: Zero Emissions Innovation Centre (ZEIC) Case Study: OSO – ZEBx