ECO-STRUCTURE recently caught up with Loraine Fowlow, faculty advisor for TRTL, the University of Calgary’s entry for the U.S. Department of Energy’s 2011 Solar Decathlon.

How is your solar paneling unique?

Utilizing off-the-shelf solar PV components, the design of the TRTL's solar array adheres to the curved roof form of the TRTL, resulting in a unique shape for a solar array. The TRTL's 8.9-kilowatt solar array is tuned to maximize solar exposure while honoring the curved architectural form, achieving 95 percent of the potential efficiency for the region. A system of microinverters maximizes the output from each PV panel under all conditions. The distributed conversion scheme is safer to install than traditional systems due to its lower voltages, and allows the performance of each panel to be monitored individually.

Distributed energy represents an important opportunity, especially for native communities [Canada's First Nations] where infrastructure and energy costs are high and rising. Many remote access areas still rely on diesel generation; utility costs may exceed $1,000 per month. Examples of renewable-energy projects in native communities are discussed in INAC's Sharing Knowledge for a Better Future. As this document points out, strong support from policy, funding, and industry partners are critical to success.

What other sustainable features have you incorporated into your design?

TRTL's mechanical systems are housed in the central core, which minimizes plumbing and ducts. This also meets contemporary needs for privacy by separating gathering and private spaces. Using resources efficiently is an important part of environmental and economic sustainability. TRTL's efficient appliances, lighting, and mechanical system are expected to use 70 percent less energy than those of a conventional building of the same size. An efficient washing machine, low-flow plumbing, and a low-flow toilet also help to ensure efficient use of water.

The mechanical system is purely electric and is powered entirely by the photovoltaic array, thereby offering reduced operating costs, and maintenance needs other. An air-source heat pump is the main mechanical component. The heat pump uses a bidirectional refrigeration cycle to move thermal energy, which is far more efficient than using a heating element to convert electricity directly into heat. It is a simple, efficient, and cost-effective way to ensure comfort throughout the home.

TRTL's shell consists of a steel sub-frame wrapped in TitanWall SIPs. Their magnesium-oxide composition provides resistance to fire and mold, and adds extreme durability and therefore efficient life-cycle costing. With reduced operating, maintenance, and replacement costs, the home's projected life cycle of 75 to 100 years provides opportunity for long-term community investment.

What was the inspiration of your design, and does it display any regional influences?

While TRTL emerged from collaboration with our Native Treaty 7 partners [composed of seven First Nations] , many other Native groups across North America use the tipi for traditional housing. Inspired by the tipi, the house's rounded form, east-facing entrance, and south-facing windows relate to the sun as a traditional source of energy and life. The two-bedroom, open-concept design is flexible and includes ample space for storage, recreation, and communal gatherings for meals.

How has the new affordability criteria affected the design of your house?

The introduction of the affordability contest aligned with Team Canada’s intention to position TRTL as a viable and affordable housing option for remote First Nations communities. All systems and design decisions were made with an eye to maintaining an overall budget that would be in an affordable range for the target market. In terms of design response, attention to overall budget influenced such decisions as material choices, mechanical and electrical systems, and ready-made kitchen and bathroom cabinetry. For example, custom millwork was avoided in favor of off-the shelf components and systems. With an eye to incorporating design elements that could be assembled and installed without skilled labor, choices such as easy-to-install cork floor tiles, and ready-to-assemble kitchen were made.

What will happen to the house after the Solar Decathlon?

To ensure the greatest impact in terms of knowledge-sharing and dissemination, Canada’s team is exploring opportunities to place TRTL on the University of Calgary campus or in the surrounding community. This effort is being guided by its university, community, and sponsor stakeholders as a continuation of the project’s collaborative spirit. A legacy team is also being built to develop and implement future plans, including post-competition monitoring, LEED certification, life-cycle analysis, and design refinement based on lessons learned. An interactive education program is also in progress to engage native K–12 students.