Stored Solar Heat Warms Alberta Development
When homeowners begin moving into the Drake Landing Solar Community in Okotoks, Alberta, in early 2006, they will usher in what many hope will be a new trend in housing developments. All 52 homes in Drake Landing, developed by the Calgary-based Sterling Group of Companies, will meet the R-2000 program requirements (reducing energy use by about 30% compared to conventional homes) and will be certified to the highest level in the Built Green™ Alberta program. They will also employ low-flow fixtures and appliances, use collected rainwater for irrigation, and rely on solar hot water panels to supply 60% of domestic hot water needs. Most exceptional, however, is the community’s heating system: the homes in Drake Landing will share North America’s first residential, seasonal-storage, solar-thermal district heating system.
About 25,000 ft2 (2,300 m2) of solar collectors mounted on the south sides of the development’s garages will generate up to 5.1 million Btu per hour (1.5 MW) of thermal power on a typical sunny day. During the summer, this heat will be stored in a borehole field under the community park. The field, which includes 144 holes each drilled 120 feet (37 meters) deep, is covered by sand, high-density R-40 insulation, a waterproof membrane, clay, and other landscaping materials, according to Mike Noble, president and CEO of EnerWorks, Inc., which supplied the solar thermal collector technology for the project. The ground in this area is expected to reach 176°F (80°C) by the end of each summer.
During cloudy days in the winter, heat extracted from the field will be sent back to the homes via underground, insulated pipes. Air handlers in each home will disperse the heat through forced air. If the water temperature is insufficient, a natural gas boiler housed in the development’s central energy building “will top it off as required,” says Keith Paget, manager of special projects and product development at the Sterling Group of Companies. On sunny days, solar energy will bypass the underground system and be used immediately in the homes.
Although heavy rains have slowed the construction schedule, homeowners in the first of two phases of development will begin moving in during February 2006; the second phase is expected to be complete by the summer of 2007. “Customers have been very enthusiastic,” Paget told EBN, noting that some buyers were attracted by the environmentally friendly nature of the homes while others were more interested in the resulting low energy bills. “The people are paying the cost of a standard home the same size,” Paget says. “All R-2000 upgrades and all the solar technology is paid by various grants from all levels of federal, provincial, and municipal government.”
Drake Landing is a demonstration project; without government funding, the development would not have been profitable at this scale. “To really do the project justice, it should have more like 800 or 1,000 homes,” says Paget. But even this small community should provide data that may support similar, larger developments in the future. Once all of the solar collectors are functioning, “it will take two full years for the system to really heat up,” according to Paget, so “about three years from today we’ll really know whether this is a huge success or just a moderate one. In the meantime, we’ll have demonstrated how to do it. Somebody’s got to start.” Noble agrees: “Once you show it can be done, then others will follow,” he told EBN. “I call Sterling a champion.”
For more information:
Mike Noble, President and CEO
Dorchester, Ontario, Canada
516-268-6500, ext. 108; 519-268-6292 (fax)
Keith Paget, Manager of Special Projects and Product Development
Sterling Group of Companies
Calgary, Alberta, Canada