Stored Solar Heat Warms Alberta Development

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.