Published on September 28th, 2012 | by April Streeter0
Nothing boring about boreholes
Humans have been ingeniously tapping the heating and cooling power of the earth for centuries. You can call that practice cleantech when a company finds a smart way to use this geothermal capacity to cut your heating bill by half every month.
For that is what is happening at a number of the buildings using seec’s Borehole Thermal Energy Storage System (btes). seec’s btes seems simple if you watch it being installed – drillers place deep holes in rings in an open space adjacent to a new building. These holes, drilled in concentric circles, are actually reservoirs, storing the warmth of summer’s sun, to be gradually accessed during winter’s chill – or vice versa, storing chilly air for summer air conditioning. Combined with heat pumps, auxiliary equipment, and an intelligent control system, btes can keep a building’s temperature comfy year-round.
With house heating and cooling comprising up to 40 percent of global energy use, btes represents a significant opportunity to cut energy use and corresponding greenhouse gas emissions.
“Half of the boreholes in use globally are in Europe, and half of those are in Sweden,” said seec ceo Johan Larsson. “We have a lot of experience here, and of course, we have the need for space heating. In regions where the cost of space heating of large buildings is high, with rising oil or gas costs, btes is going to be attractive.”
A seec btes system requires a higher upfront investment than other heating and cooling systems, which is one reason this simple but highly effective solution is more popular in regions where oil or gas costs are rising steeply. Larsson cites three important seec btes sites that he says show the potential of the technology. At a sports complex called Backavallen in the city of Katrineholm, keeping the ice hockey rink ready for action year round generates a lot of waste heat.
These days, that heat is stored in btes boreholes, and, among other uses, warms the ground under the soccer pitch.
In the small city of Sigtuna outside Stockholm, an apartment building called Rondell House at Steningehöjden is getting its heat from a btes system, which has worked so effectively – reducing energy requirements by nearly three quarters – that the property owner, Sigtunahem, will use btes as it further develops the district.
Lastly, a large eco-project in Stockholm’s former industrial harbor area called Stockholm Royal Seaport will serve as an important showcase for seec’s technology. A striking seven-story steel-facade apartment building being constructed by Reinhold Gustafsson Förvaltnings AB will have a btes borehole system because it is, according to the developers, the “most effective” way to heat the building and be in line with strict municipal energy-use requirements for the Stockholm Royal Seaport development.
btes can also work in tandem with wind power, solar, or hydro to provide low-CO2 heating and cooling systems. Because the cost of drilling the reservoir wells is significantly lower in areas where drilling technology has advanced, Larsson sees Norway as the next big market opportunity, with Canada and North America as subsequent target regions.