The temperature outside is constantly changing, but the temperature of the earth a few meters below the surface stays constant throughout the year. This means that no matter the outside temperature, the ground always provides the same temperature. When designing the Earth Rangers Centre, we decided to harness this energy, in order to improve the energy efficiency of the building and decrease greenhouse gas emissions.
Whether you are on a beach in Jamaica or skiing in Banff, the sub surface ground temperature adopts the mean annual temperature of that location, all around the world and throughout the year. This is the prime concept on which a geothermal system is based. At the ERC there are two parts to this system; the primary part consists of 40 vertical boreholes drilled 160 meters into the ground. The secondary part, located inside the building, consists of 22 km of tubing that has been embedded in the concrete structure. The tubing transports the ground tempered fluid through the concrete, exchanging the energy directly with the structure of the building. The concrete acts like a battery that stores heat. During winter, the hot fluid running through the tubes heats up the concrete which then radiates the heat into the building, keeping the space warm. During the summer, the fluid running through the tubes is cooler and this cools the concrete structure which in turn cools the building.
A recent study by National Research Council Canada shows that approximately 50% of the energy consumption in a typical Canadian commercial building is used for heating and cooling purposes. On an average summer day we’re able to maintain a comfortable internal temperature of 21 degrees Celsius throughout the 64,000 square foot building using less than 800 watts of energy; the same amount of energy used to power a regular household toaster. By comparison, typical conventional cooling systems would use upwards of 20 times more. Imagine the reduction in peak summer time power consumption a geothermal system can achieve.
While impressive, we still need a way of knowing that the geothermal system is performing at optimum levels. To do this, we look at something called the Coefficient of Performance (COP). The COP is the ratio between the heating or cooling the system provides and the electrical power used. The higher the COP, the more energy efficient the system. A COP of 100 is an extremely impressive achievement and one that the ERC regularly attains and surpasses, proving that the geothermal system is performing at optimal standards. The COP at the ERC during cooling mode reached a peak of 326.16 earlier this year, which is pretty incredible, if we do say so ourselves!
The design of the ERC’s geothermal system has proven extremely successful, but we’re still always looking for ways to be more efficient and spread the message. We recently partnered with Geosource Energy Inc., one of Canada’s leading geothermal companies, to further optimize our system and help raise awareness about the benefits of geothermal systems. The Earth Rangers Centre has a long history of working with like-minded organizations to push the envelope on sustainable technologies. We are hopeful that our partnership with Geosource Energy Inc. will not only create more efficiencies within our building but also help others better understand the value and impact of geothermal heating and cooling as a truly sustainable technology.