Since 2010, the Biodôme has been powered by an open-loop geothermal system. The idea to install such a system emerged after the discovery of a large phreatic zone beneath the Biodôme site. It is now one of the largest open-loop geothermal systems in Canada.
Geothermal systems are designed to capture heat from the ground or from phreatic zones to provide heating and cooling for buildings. In Quebec, this natural energy source can be used year-round, depending on the season. In summer, the cool temperatures of the underground environment help to air-condition buildings, while in winter, stored geothermal heat can be drawn up for heating. There are two common types of geothermal systems:
- Open-loop systems, which draw heat from a lake or a phreatic zone. These systems include one well that pumps up groundwater and another that returns the used water back to the source.
- Closed-loop horizontal systems, which collect heat from the shallow ground using a network of buried pipes that circulate a heat-transfer fluid in a closed circuit.
The Biodôme uses groundwater drawn from a phreatic zone located 20 metres below the surface. The heat from the pumped water is transferred to a special liquid called glycol, which circulates through an independent pipe system. Glycol is used because it transfers heat more efficiently than water.
The glycol flows through a network of heat pumps that cool or heat the Biodôme’s various ecosystems. After passing through the heat exchanger, the groundwater is returned to the phreatic zone—without ever coming into direct contact with the glycol. In the event of a system failure, safeguards are in place to ensure the continued well-being of the Biodôme’s living collections.
Using groundwater responsibly
To prevent any risk of contaminating the phreatic zone, the Biodôme maintains constant oversight of the water quality used in its geothermal system. The water’s chemical composition is monitored continuously, with data submitted to Quebec’s Ministry of the Environment, the Fight against Climate Change, Wildlife and Parks (MELCCFP).
This type of installation must also comply with municipal and provincial regulations on water use, to maintain stable levels in the phreatic zone and prevent ground depletion.
Through these rigorous control and compliance measures, the Biodôme’s geothermal system ensures responsible, long-term use of this natural resource, without negatively affecting the quality or level of the phreatic zone.
Greater energy potential than expected
When the Planétarium was built next to the Biodôme in 2012, the exceptional performance of the Biodôme’s geothermal system made it possible to connect the new building to the same heating and cooling infrastructure.
This shared use of resources significantly improved the Planétarium’s overall energy efficiency. In fact, integrating geothermal energy played a key role in the Planetarium earning its LEED Platinum certification.
Technical specifications of the Biodôme’s geothermal system
- One intake well and one return well draw groundwater from a phreatic zone located 20 metres deep.
- Three heat pumps with 450 tons of cooling capacity (1,582.60 kW) and one 250-ton unit (879.21 kW) are dedicated primarily to the Labrador Coast and subantarctic island ecosystems.
- Refrigerant type: 134A
- Coolant fluid in the chilled water loop: 30% glycol solution
- A 25 HP submersible pump draws groundwater at a rate of 1,900 litres per minute. The water is returned to the phreatic zone by gravity, without any alteration.
Energy-efficient upgrades during the Biodôme’s migration project
The 2018 Biodôme Migration Project provided an opportunity to enhance the energy potential of the geothermal system while significantly reducing overall energy use and greenhouse gas (GHG) emissions.
New, more energy-efficient systems replaced several outdated and energy-intensive mechanical components. For instance, electric baseboard heaters dating back to the 1976 Olympic Velodrome were replaced with a high-performance heating system. Fan coil units, supplied with hot glycol from the geothermal system, were installed around the perimeter of the Biodôme’s fenestration. This upgrade has led to a notable reduction in electricity consumption.
A unique ice tunnel cooling system
The installation of an ice tunnel in the Sub-Antarctic Islands ecosystem is one of the Biodôme’s major innovations and a source of pride. This world-first concept was developed and designed by the museum’s in-house technical team. Real ice forms on the tunnel’s walls using excess cooling capacity from the heat pumps, which are themselves connected to the geothermal system.
The ice tunnel’s structure consists of finned serpentine pipes, similar to the old-fashioned radiators that circulated hot water to heat a room. In this case, a glycol solution chilled to –8 degrees Celsius circulates through the pipes, forming a layer of ice on their surface. This system uses virtually no additional energy, as it is fully supported by the capacity of the geothermal loop.