The next generation of passive solar for cold climates

The Ryerson University HelioArch test.
Photo courtesy Ryerson University

Although the calculations in HelioArch are only theoretical at this point, and more scale models are required to verify the concept, it appears the technology may be a viable alternative to fossil-fuel heating systems in cold climates. The capture efficiencies are presently approximately double (about 30 per cent) of PV and battery systems (less than 15 per cent), and are rising as the design and testing of the system progresses.  The concept is designed for cold climates, where water is plentiful and there is enough full sunlight to carry the building through the winter months. The system is tightly integrated into the architecture of the building, leaving behind the present model of using mechanical units to overcome the weaknesses of the architect’s design. In this case, the architect must use the HelioArch software early in the design process to correctly balance the system while orientating and designing the building on the site.

However, items still need to be addressed, such as keeping the thermal mass free from algae and the maintenance of the heliostats. If the thermal mass was integrated into the structure of the building, moisture issues with the surrounding architecture would need to be adequately dealt with. If a critical component of the system were to fail, a backup heating system would be required to carry the system and building into the spring.

The system could be adaptable to many different configurations and building types. The model shown in this article takes a very simplistic approach to design to find the lowest common denominator; based on this work, the concept can be scaled up to fit more complicated building types, as long as there is room for the heliostats and a higher-capacity thermal mass, which is an obvious problem in urban areas. Integrating the system on building rooftops could be one option on tight sites.

Architects are aiming for all new buildings to be carbon-neutral by 2030, but this goal is still very far away. Today’s design practices will need to undergo a fundamental change to reach such an objective, especially in cold climates such as Canada. It is this author’s opinion thermal mass technologies like HelioArch are crucial to achieving this goal.

By keeping the system simple and minimizing both the transfer and transformation of energy, it is possible to efficiently harness the power of the sun. With further testing, a properly designed HelioArch may provide the means to satisfy all heating energy requirements of a building. By reducing these requirements for a dwelling, separation from the grid via small PV and battery-storage systems becomes more possible.

Mark Driedger is an architect with ATA Architects Inc. in Toronto and Oakville, Ont.  He is also an adjunct professor with Lawrence Technological University in Detroit. Driedger continues to integrate science with design. He can be contacted at

Control the content you see on! Learn More.
Leave a Comment


Your email address will not be published. Required fields are marked *