INNOVATION March-April 2014

f ea t ures

Energy at Your Feet Geoexchange Taps Solar Heat Stored in the Earth

D’Arcy Jenish

One of the most abundant, reliable and cleanest forms of energy on Earth may well be right beneath your feet, or your home, your office or your plant. It is the solar energy that the earth absorbs and stores every day and there is a proven and fail-safe technology available for using that energy to heat or cool residential, commercial and institutional buildings. The technology in question is known as geoexchange, or geothermal exchange. It is widely used in some parts of the Southern and Midwestern United States and it has gained wide acceptance in many European countries, which are not blessed with abun- dant and relatively inexpensive supplies of oil, natural gas, coal and hydro-electricity. Geoexchange has been a tougher sell in Canada largely because the country is one of the world’s leading producers of fossil fuels and hydro is abundant. But that is changing, thanks to the growing public concern over climate change and increased awareness of the environmental impact of greenhouse gas emissions. “The upside,” says Ruben Arellano, P.Eng., a geological engineer with Burnaby-based Associated Engineering and Past President of GeoExchange BC, an industry association devoted to promoting best practices, “is that there is a lot of pressure on building owners to adopt more sustainable design approaches—and more green energy, including geoexchange, is one of them.” Furthermore, the geoexchange industry is more advanced in BC than in other parts of the country. High utility rates, along with the moderate climate in the Lower Mainland, These photos illustrate the two types of geothermal systems—horizontal closed loop and vertical closed loop. In the horizontal systems,such as the one depicted in the photo above, liquids are pumped from a building and through this extensive network of plastic pipes to absorb heat.The photo on the right shows the distribution and collection mains of a vertical closed loop system. Liquid flows through the distribution mains,through pairs of vertical pipes to absorb heat and finally back to a building through collection mains. (Photo credit: GeoExchange BC.)

18

M a r ch/A p r i l 2 014

i n n o v a t i o n