Green building sinks pipes into earth
From a depth of 42 metres where it’s 12 C, the warm of the earth will be used to cut hot water heating bills by more than half.
On top of the four-storey building at Brown Avenue and 222nd Street, the roof will be a light-gray colour to reflect the sun and prevent a micro climate around the building, when summer temperatures turn buildings into ovens and raise nearby temperatures outside by a couple degrees.
Shades will keep the summer sun from hitting the energy-efficient windows – further keeping the building cool in the summer. Combined with walls insulated to a value of R-23, the new building won’t need air conditioning – ever.
Same with the natural gas.
There won’t be any.
Electric baseboard heating will keep the small apartments warm, without burning hydrocarbons, while flow low-toilets and fixtures will cut down on water use.
Such measures are expected to qualify the project known as Alouette Heights, for a gold rating in the Leadership in Energy and Environment Design standards, one below the top rating of platinum.
The project should be complete by summer 2012 and will have 46 small apartments, maximum 570 sq. feet. in size where people can live temporarily as they rebuild their lives from drug addiction or mental health issues.
B.C. Housing is paying for the project which will be operated by the Alouette Home Start Society.
While a decade ago all of the energy-saving strategies would have been cutting edge, today they’re mainstream, says Nelson de Amaral with Darwin Construction, the North Vancouver firm that’s building Alouette Heights.
Green buildings have become so much cheaper it adds only five per cent to the cost, with the result that the trend is now industry wide, says de Amaral.
“Every project in one way or the other becomes a green project.
“There isn’t a huge cost to most of these projects.”
Even as little as three or four years ago, costs were higher, he added.
Even the geo-thermal system used in Alouette Heights accounted for a small percentage of the cost, less than $100,000.
The geo-thermal system will be used only for pre-heating of water for the shower and kitchen, the payback period will be 10 to 15 years.
If the building had in-floor radiant heating, or if natural gas was being used, that period would be shortened.
Other features include use of LED fixtures in emergency exit signs and compact flourescents everywhere else.
Use of water-absorbent plants and shallow ditches will trap storm water and filter it before it enters the storm sewer system at about half the volume that would normally occur.
While the project is built in the downtown, Maple Ridge district still requires a sediment and erosion control plan to ensure streams don’t get loaded with mud and sludge from construction activities. Therefore, a portable water filtration and treatment unit is on site to treat any water from the site before it’s discharged to the storm drains.
About 90 per cent of construction waste will be recycled while use of pre-fabricated exterior walls will further cut waste.
Sheila McLaughlin with the Alouette Home Start Society pointed out all B.C. government-funded projects now must be LEED gold standards.
With geothermal almost completed, work now can start on the foundation.
“We’re really excited that now it’s going to rise above the ground,” she said.
McLaughlin society will now start working with different agencies in order to place people into the building. The facility will be staffed 24 hours a day and each resident must be in a recovery program.
Opening day should be sometime in the summer of 2012.
Ground will preheat water to 12 C
While it’s known as geothermal, the system used in Alouette Heights to pre-heat the water for the kitchen and bathroom actually has a more accurate, though less-exciting label.
“What we’re doing is actually an earth-sourced heat-pump system, but the industry accepts it as geothermal, so it’s geothermal,” explains Scott Steward, with Ground Source Drilling.
The system used in Alouette Heights is one of the most conventional types and can be installed anywhere in the country, although B.C. and Atlantic Canada seem to be in the forefront.
Steward pointed out that energy savings could be higher if natural gas was used to heat the water, but using electricity means there’s no burning of hydrocarbons.
In the Alouette Heights project, 24 holes have been drilled 42 metres down into the earth. Two one-inch-wide plastic pipes are inserted down the holes. One pipe carries the water and anti-freeze mixture down and the other takes it back up, after it’s been warmed to 12 C by the earth.
The anti-freeze used is food-grade propylene glycol, so it’s safe, Steward adds. The high-density polyethylene pipes will last at least 50 years and are earthquake resistant.
When the warmer water comes back up, it goes to a heat exchanger, which extracts the heat and transfers it to the municipal water, warming it to 12 C before it goes into the hot water tank, reducing heating costs by about two-thirds.
Steward stressed that the design of each geothermal system is critical to ensure minimum pay back period for a building.
“There’s no question it pays for itself.”
“With the way that we’re going, as far as being green, for that aspect, it’s a no-brainer. It’s absolutely fantastic.”