Solar air heating is among the most cost-effective applications of solar thermal energy. These systems are used for space heating and preheating fresh air for ventilation, typically using glazed or unglazed perforated solar collectors. The collectors draw in outside air, heat it using solar energy, and then distribute it through ductwork to meet building heating and fresh air needs. In 2024, Canada led again the world for the at least seventh year in a row in solar air heating adoption. The four key suppliers – Trigo Energies, Conserval Engineering, Matrix Energy, and Aéronergie – reported a combined 26,203 m2 (282,046 ft2) of collector area sold last year. Several of these providers are optimistic about the growing demand. These findings come from the newly released Canadian Solar Thermal Market Survey 2024, commissioned by Natural Resources Canada. Canada is the global leader in solar air heating. The market is driven by a strong network of experienced system suppliers, optimized technologies, and a few small favorable funding programs – especially in the province of Quebec. Architects and developers are increasingly turning to these cost-effective, façade-integrated systems as a practical solution for reducing onsite natural gas consumption. Despite its cold climate, Canada benefits from strong solar potential with solar irradiance in many areas rivaling or even exceeding that of parts of Europe. This makes solar air heating not only viable, but especially valuable in buildings with high fresh air requirements including schools, hospitals, and offices. The projects highlighted in this article showcase the versatility and relevance of solar air heating across a range of building types, from new constructions to retrofits. Figure 1: Preheating air for industrial buildings: 2,750 m2 (29,600 ft2) of Calento SL solar air collectors cover all south-west and south-east facing facades of the FAB3R factory in Trois-Rivières, Quebec. The hourly unitary flow rate is set at 41 m3/m2 or 2.23 cfm/ft2 of collector area, at the lower range because only a limited number of intake fans was close enough to the solar façade to avoid long ventilation ductwork. Photo: Trigo Energies Quebec’s solar air heating boom: the Trigo Energies story Trigo Energies makes almost 90 per cent of its sales in Quebec. “We profit from great subsidies, as solar air systems are supported by several organizations in our province – the electricity utility Hydro Quebec, the gas utility Energir and the Ministry of Natural Resources,” explained Christian Vachon, Vice President Technologies and R&D at Trigo Energies. Trigo Energies currently has nine employees directly involved in planning, engineering and installing solar air heating systems and teams up with several partner contractors to install mostly retrofit projects. “A high degree of engineering is required to fit a solar heating system into an existing factory,” emphasized Vachon. “Knowledge about HVAC engineering is as important as experience with solar thermal and architecture.” One recent Trigo installation is at the FAB3R factory in Trois-Rivières. FAB3R specializes in manufacturing, repairing, and refurbishing large industrial equipment. Its air heating and ventilation system needed urgent renovation because of leakages and discomfort for the workers. “Due to many positive references he had from industries in the area, the owner of FAB3R contacted us,” explained Vachon. “The existence of subsidies helped the client to go for a retrofitting project including solar façade at once instead of fixing the problems one bit at a time.” Approximately 50 per cent of the investment costs for both the solar air heating and the renovation of the indoor ventilation system were covered by grants and subsidies. FAB3R profited from an Energir grant targeted at solar preheating, plus an investment subsidy from the Government of Quebec’s EcoPerformance Programme.   Blue or black, but always efficient: the advanced absorber coating In October 2024, the majority of the new 2,750 m² (29,600 ft2) solar façade at FAB3R began operation (see figure 1). According to Vachon, the system is expected to cover approximately 13 per cent of the factory’s annual heating demand, which is otherwise met by natural gas. Trigo Energies equipped the façade with its high-performance Calento SL collectors, featuring a notable innovation: a selective, low-emissivity coating that withstands outdoor conditions. Introduced by Trigo in 2019 and manufactured by Almeco Group from Italy, this advanced coating is engineered to maximize solar absorption while minimizing heat loss via infrared emission, enhancing the overall efficiency of the system. The high efficiency coating is now standard in Trigo’s air heating systems. According to the manufacturer, the improved collector design shows a 25 to 35 per cent increase in yield over the former generation of solar air collectors with black paint. Testing conducted at Queen’s University confirms this performance advantage. Researchers measured the performance of transpired solar air collectors both with and without a selective coating, mounted side-by-side on a south-facing vertical wall. The results showed that the collectors with the selective coating produced 1.3 to 1.5 times more energy than those without it. In 2024, the monitoring results were jointly published by Queen’s University and Canmat Energy in a paper titled Performance Comparison of a Transpired Air Solar Collector with Low-E Surface Coating. Selective coating, also used on other solar thermal technologies including glazed flat plate or vacuum tube collectors, has a distinctive blue color. Trigo customers can, however, choose between blue and black finishes. “By going from the normal blue selective coating to black selective coating, which Almeco is specially producing for Trigo, we lose about 1 per cent in solar efficiency,” explained Vachon. Figure 2: Building-integrated solar air heating façade with MatrixAir collectors at the firehall building in Mont Saint Hilaire, south of Montreal. The 190 m2 (2,045 ft2) south-facing wall preheats the fresh air, reducing natural gas consumption by 18 per cent compared to the conventional make-up system. Architect: Leclerc Architecture. Photo: Matrix Energy Matrix Energy: collaborating with architects and engineers in new builds The key target customer group of Matrix Energy are public buildings – mainly new construction. “Since the pandemic, schools are more conscious about fresh air, and solar preheating of the incoming fresh air has a positive impact over the entire school year,” noted Brian Wilkinson, President of Matrix Energy. Matrix Energy supplies systems across Canada, working with local partners to source and process the metal sheets used in their MatrixAir collectors. These metal sheets are perforated and then formed into architectural cladding profiles. The company exclusively offers unglazed, single-stage collectors, citing fire safety concerns associated with polymeric covers. “We have strong relationships with many architects and engineers who appreciate the simplicity and cost-effectiveness of transpired solar air heating systems,” said President Brian Wilkinson, describing the company’s sales approach. “Matrix handles system design and supplies the necessary materials, while installation is carried out by specialized cladding and HVAC contractors overseen by on-site architects and engineers,” Wilkinson added. Finding the right flow: the importance of unitary airflow rates One of the key design factors in solar air heating systems is the amount of air that passes through each square meter of the perforated metal absorber,  known as the unitary airflow rate. The principle is straightforward: higher airflow rates deliver more total heat to the building, while lower flow rates result in higher outlet air temperatures. Striking the right balance between air volume and temperature gain is essential for efficient system performance. For unglazed collectors mounted on building façades, typical hourly flow rates should range between 120 and 170 (m3/h/m2), or 6.6 to 9.4 cfm/ft2. However, Wilkinson suggests that an hourly airflow rate of around 130 m³/h/m² (7.2 cfm/ft2) offers the best cost-benefit balance for building owners. If the airflow is lower, the system will deliver higher air temperatures, but it would then need a much larger collector area to achieve the same air volume and optimum performance, he explained. It’s also crucial for the flow rate to overcome external wind pressure. As wind passes over the absorber, air flow through the collector’s perforations is reduced, resulting in heat losses to the environment. This effect becomes even more pronounced in taller buildings, where wind exposure is greater. To ensure the system performs well even in these conditions, higher hourly airflow rates typically between 150 and 170 m³/m² (8.3 to 9.4 cfm/ft2)  are necessary. Figure 3: One of three apartment blocks of the Maple House in Toronto’s Canary District. Around 160 m2 (1,722 ft2) of SolarWall collectors clad the two-storey mechanical penthouse on the roof. The rental flats have been occupied since the beginning of 2024. Collaborators: architects-Alliance, Claude Cormier et Associés, Thornton Tomasetti, RWDI, Cole Engineering, DesignAgency, MVShore, BA Group, EllisDon. Photo: Conserval Engineering Solar air heating systems support LEED-certified building designs Solar air collectors are also well-suited for use in multi-unit residential buildings. A prime example is the Canary District in Toronto (see Figure 3), where single-stage SolarWall collectors from Conserval Engineering have been installed on several MURBs to clad the mechanical penthouses. “These penthouses are an ideal location for our air heating collectors, as they contain the make-up air units that supply corridor ventilation throughout the building,” explained Victoria Hollick, Vice President of Conserval Engineering. “The walls are typically finished with metal façades, which can be seamlessly replaced with a SolarWall system – maintaining the architectural language without disruption.” To date, nine solar air heating systems have been commissioned in the Canary District, covering a total collector area of over 1,000 m² (10,764 ft2). “Our customers have many motivations to integrate SolarWall technology into their new construction or retrofit projects, either carbon reduction, ESG, or green building certification targets,” explained Hollick. The use of solar air collectors in the Canary District was proposed by architects from the Danish firm Cobe. The black-colored SolarWall system preheats incoming air before it is distributed to the building’s corridors and common areas, reducing reliance on natural gas heating and supporting the pursuit of LEED Gold certification. Hollick estimates the amount of gas saved between 10 to 20 per cent of the total heating load for the corridor ventilation of the multi-unit residential buildings. Additional energy-saving strategies include a 50/50 window-to-wall ratio with high-performance glazing, green roofs, high-efficiency mechanical systems, LED lighting, and Energy Star-certified appliances. The ideal orientation for a SolarWall system is due south. However, the systems can be built at any orientation up to 90° east and west, explained Hollick. A SolarWall at 90° would have approximately 60 per cent of the energy production of the same area facing south.Canada’s expertise in solar air heating continues to set a global benchmark, driven by supporting R&D, by innovative technologies, strategic partnerships, and a growing portfolio of high-impact projects. With strong policy support and proven performance, solar air heating is poised to play a key role in the country’s energy-efficient building future. Figure 4: Claude-Bechard Building in Quebec is a showcase project for sustainable architecture with a 72 m2 (775 ft2) Lubi solar air heating wall from Aéronergie. It serves as a regional administrative center. Architectural firm: Goulet et Lebel Architectes. Photo: Art Massif Bärbel Epp is the general manager of the German Agency solrico, whose focus is on solar market research and international communication. The post Op-ed: Canada’s leadership in solar air heating—Innovation and flagship projects appeared first on Canadian Architect.

The latest recipients of the OAA’s Public Awareness Sponsorship program, held twice a year, have been announced. Under its five-year strategic plan, the OAA has identified public education as a key pillar with the goal to advance the public’s understanding and recognition that architecture is integral to the quality of life and well-being of society. As a result, the OAA offers Public Awareness Funding in amounts from $500 to $10,000 to applicants working to expand an awareness of the value of architecture in their communities. The Communications and Public Education Committee (CPEC) has agreed to fund the following applicants. Toronto Public Space Committee and Cyan Station – To the Loo! Toronto Toilet Design Challenge The “To the Loo! Toronto Toilet Design Challenge” is a global call to reimagine public washrooms as vital elements of the urban landscape. A joint effort by the Toronto Public Space Committee and Cyan Station, the initiative emphasizes accessibility, public health, and innovative design. Featuring a summer 2025 public event and exhibition, the challenge invites architects, designers, and engaged citizens to explore creative solutions that transform how we experience these essential public spaces. Heritage Ottawa – 2025 Heritage Ottawa Walking Tours Heritage Ottawa is an advocate for the preservation and appreciation of Ottawa’s built heritage. For more than 50 years, its signature guided Walking Tours, offered in both English and French, have attracted diverse audiences and have highlighted the city’s architectural and cultural history. Kelvin Kung – Designing Dignity: Community-Driven Insights for Better Palliative and Long-Term Care Spaces “Designing Dignity: Community-Driven Insights for Better Palliative and Long-Term Care Spaces” focuses on enhancing the quality of life for aging populations by reimagining care spaces through thoughtful architectural design. By leveraging online engagement tools, AI-driven analysis, and stakeholder input, this initiative will develop data-driven reports and recommendations for the public, policymakers, and design professionals. The project aims to raise awareness about architecture’s crucial role in shaping compassionate care spaces, empowering communities to advocate for better design and influence future policies and practices. McEwen School of Architecture, Laurentian University – Archi-North Summer Camp Archi·North Summer Camp, offered by Laurentian University’s McEwen School of Architecture, is a bilingual and tricultural program designed for Northern Ontario high school students entering Grades 11 and 12. The week-long, immersive camp aims to provide an affordable introduction to architectural design through hands-on experience in drafting, model-making, and digital tools with an emphasis on sustainable materials. Led by faculty and recent graduates, the Sudbury-based camp encourages youth to be agents of change and reimagine their own communities. Moses Structural Engineers Inc. – TimberFever 2025 Now in its 11th year, TimberFever 2025, presented by Moses Structural Engineers, is a hands-on design-build competition that brings together architecture and engineering students from Canadian and U.S. universities to collaborate, create, and innovate. Under the guidance of professional mentors, carpenters, and industry leaders, participants tackle real-world challenges like affordable housing and climate resilience while refining both design and construction skills. RAW Design – Architectural and Design Summer Camp, “Diversity in Design” RAW Design’s “Diversity in Design” Summer Camp introduces underrepresented high school students to the architecture profession through an immersive, hands-on experience. Now in its fifth year, this free week-long mentorship program fosters creativity, critical thinking, and teamwork with activities like model-making, workshops, and urban exploration led by architects and volunteers. Urban Minds – 1UP Fellowship 2025-2026 Urban Minds’ 1UP Fellowship 2025-2026 aims to empower high school students across Ontario to become urban changemakers through mentorship and hands-on projects. The Fellowship features two streams: the Design-Builders Stream, where students launch school chapters to tackle community design challenges, and the Learners Stream, which introduces students to city-building topics through structured learning activities. The next deadline for submissions is September 15, 2025. For more information, click here. The post Recipients of Public Awareness Sponsorship Program announced appeared first on Canadian Architect.

If you’ve ever flown through outer space, at least while watching a documentary or a science fiction film, you’ve seen how artists turn astronomical findings into stunning visuals. But in the process of visualizing data for their latest planetarium show, a production team at New York’s American Museum of Natural History made a surprising discovery of their own: a trillion-and-a-half mile long spiral of material drifting along the edge of our solar system. “So this is a really fun thing that happened,” says Jackie Faherty, the museum’s senior scientist. Last winter, Faherty and her colleagues were beneath the dome of the museum’s Hayden Planetarium, fine-tuning a scene that featured the Oort cloud, the big, thick bubble surrounding our Sun and planets that’s filled with ice and rock and other remnants from the solar system’s infancy. The Oort cloud begins far beyond Neptune, around one and a half light years from the Sun. It has never been directly observed; its existence is inferred from the behavior of long-period comets entering the inner solar system. The cloud is so expansive that the Voyager spacecraft, our most distant probes, would need another 250 years just to reach its inner boundary; to reach the other side, they would need about 30,000 years.  The 30-minute show, Encounters in the Milky Way, narrated by Pedro Pascal, guides audiences on a trip through the galaxy across billions of years. For a section about our nascent solar system, the writing team decided “there’s going to be a fly-by” of the Oort cloud, Faherty says. “But what does our Oort cloud look like?”  To find out, the museum consulted astronomers and turned to David Nesvorný, a scientist at the Southwest Research Institute in San Antonio. He provided his model of the millions of particles believed to make up the Oort cloud, based on extensive observational data. “Everybody said, go talk to Nesvorný. He’s got the best model,” says Faherty. And “everybody told us, ‘There’s structure in the model,’ so we were kind of set up to look for stuff,” she says.  The museum’s technical team began using Nesvorný’s model to simulate how the cloud evolved over time. Later, as the team projected versions of the fly-by scene into the dome, with the camera looking back at the Oort cloud, they saw a familiar shape, one that appears in galaxies, Saturn’s rings, and disks around young stars. “We’re flying away from the Oort cloud and out pops this spiral, a spiral shape to the outside of our solar system,” Faherty marveled. “A huge structure, millions and millions of particles.” She emailed Nesvorný to ask for “more particles,” with a render of the scene attached. “We noticed the spiral of course,” she wrote. “And then he writes me back: ‘what are you talking about, a spiral?’”  While fine-tuning a simulation of the Oort cloud, a vast expanse of ice material leftover from the birth of our Sun, the ‘Encounters in the Milky Way’ production team noticed a very clear shape: a structure made of billions of comets and shaped like a spiral-armed galaxy, seen here in a scene from the final Space Show (curving, dusty S-shape behind the Sun) [Image: © AMNH] More simulations ensued, this time on Pleiades, a powerful NASA supercomputer. In high-performance computer simulations spanning 4.6 billion years, starting from the Solar System’s earliest days, the researchers visualized how the initial icy and rocky ingredients of the Oort cloud began circling the Sun, in the elliptical orbits that are thought to give the cloud its rough disc shape. The simulations also incorporated the physics of the Sun’s gravitational pull, the influences from our Milky Way galaxy, and the movements of the comets themselves.  In each simulation, the spiral persisted. “No one has ever seen the Oort structure like that before,” says Faherty. Nesvorný “has a great quote about this: ‘The math was all there. We just needed the visuals.’”  An illustration of the Kuiper Belt and Oort Cloud in relation to our solar system. [Image: NASA] As the Oort cloud grew with the early solar system, Nesvorný and his colleagues hypothesize that the galactic tide, or the gravitational force from the Milky Way, disrupted the orbits of some comets. Although the Sun pulls these objects inward, the galaxy’s gravity appears to have twisted part of the Oort cloud outward, forming a spiral tilted roughly 30 degrees from the plane of the solar system. “As the galactic tide acts to decouple bodies from the scattered disk it creates a spiral structure in physical space that is roughly 15,000 astronomical units in length,” or around 1.4 trillion miles from one end to the other, the researchers write in a paper that was published in March in the Astrophysical Journal. “The spiral is long-lived and persists in the inner Oort Cloud to the present time.” “The physics makes sense,” says Faherty. “Scientists, we’re amazing at what we do, but it doesn’t mean we can see everything right away.” It helped that the team behind the space show was primed to look for something, says Carter Emmart, the museum’s director of astrovisualization and director of Encounters. Astronomers had described Nesvorný’s model as having “a structure,” which intrigued the team’s artists. “We were also looking for structure so that it wouldn’t just be sort of like a big blob,” he says. “Other models were also revealing this—but they just hadn’t been visualized.” The museum’s attempts to simulate nature date back to its first habitat dioramas in the early 1900s, which brought visitors to places that hadn’t yet been captured by color photos, TV, or the web. The planetarium, a night sky simulator for generations of would-be scientists and astronauts, got its start after financier Charles Hayden bought the museum its first Zeiss projector. The planetarium now boasts one of the world’s few Zeiss Mark IX systems. Still, these days the star projector is rarely used, Emmart says, now that fulldome laser projectors can turn the old static starfield into 3D video running at 60 frames per second. The Hayden boasts six custom-built Christie projectors, part of what the museum’s former president called “the most advanced planetarium ever attempted.”  In about 1.3 million years, the star system Gliese 710 is set to pass directly through our Oort Cloud, an event visualized in a dramatic scene in ‘Encounters in the Milky Way.’ During its flyby, our systems will swap icy comets, flinging some out on new paths. [Image: © AMNH] Emmart recalls how in 1998, when he and other museum leaders were imagining the future of space shows at the Hayden—now with the help of digital projectors and computer graphics—there were questions over how much space they could try to show. “We’re talking about these astronomical data sets we could plot to make the galaxy and the stars,” he says. “Of course, we knew that we would have this star projector, but we really wanted to emphasize astrophysics with this dome video system. I was drawing pictures of this just to get our heads around it and noting the tip of the solar system to the Milky Way is about 60 degrees. And I said, what are we gonna do when we get outside the Milky Way?’ “Then [planetarium’s director] Neil Degrasse Tyson “goes, ‘whoa, whoa, whoa, Carter, we have enough to do. And just plotting the Milky Way, that’s hard enough.’ And I said, ‘well, when we exit the Milky Way and we don’t see any other galaxies, that’s sort of like astronomy in 1920—we thought maybe the entire universe is just a Milky Way.'” “And that kind of led to a chaotic discussion about, well, what other data sets are there for this?” Emmart adds. The museum worked with astronomer Brent Tully, who had mapped 3500 galaxies beyond the Milky Way, in collaboration with the National Center for Super Computing Applications. “That was it,” he says, “and that seemed fantastical.” By the time the first planetarium show opened at the museum’s new Rose Center for Earth and Space in 2000, Tully had broadened his survey “to an amazing” 30,000 galaxies. The Sloan Digital Sky Survey followed—it’s now at data release 18—with six million galaxies. To build the map of the universe that underlies Encounters, the team also relied on data from the European Space Agency’s space observatory, Gaia. Launched in 2013 and powered down in March of this year, Gaia brought an unprecedented precision to our astronomical map, plotting the distance between 1.7 billion stars. To visualize and render the simulated data, Jon Parker, the museum’s lead technical director, relied on Houdini, a 3D animation tool by Toronto-based SideFX. The goal is immersion, “whether it’s in front of the buffalo downstairs, and seeing what those herds were like before we decimated them, to coming in this room and being teleported to space, with an accurate foundation in the science,” Emmart says. “But the art is important, because the art is the way to the soul.”  The museum, he adds, is “a testament to wonder. And I think wonder is a gateway to inspiration, and inspiration is a gateway to motivation.” Three-D visuals aren’t just powerful tools for communicating science, but increasingly crucial for science itself. Software like OpenSpace, an open source simulation tool developed by the museum, along with the growing availability of high-performance computing, are making it easier to build highly detailed visuals of ever larger and more complex collections of data. “Anytime we look, literally, from a different angle at catalogs of astronomical positions, simulations, or exploring the phase space of a complex data set, there is great potential to discover something new,” says Brian R. Kent, an astronomer and director of science communications at National Radio Astronomy Observatory. “There is also a wealth of astronomics tatical data in archives that can be reanalyzed in new ways, leading to new discoveries.” As the instruments grow in size and sophistication, so does the data, and the challenge of understanding it. Like all scientists, astronomers are facing a deluge of data, ranging from gamma rays and X-rays to ultraviolet, optical, infrared, and radio bands. Our Oort cloud (center), a shell of icy bodies that surrounds the solar system and extends one-and-a-half light years in every direction, is shown in this scene from ‘Encounters in the Milky Way’ along with the Oort clouds of neighboring stars. The more massive the star, the larger its Oort cloud [Image: © AMNH ] “New facilities like the Next Generation Very Large Array here at NRAO or the Vera Rubin Observatory and LSST survey project will generate large volumes of data, so astronomers have to get creative with how to analyze it,” says Kent.  More data—and new instruments—will also be needed to prove the spiral itself is actually there: there’s still no known way to even observe the Oort cloud.  Instead, the paper notes, the structure will have to be measured from “detection of a large number of objects” in the radius of the inner Oort cloud or from “thermal emission from small particles in the Oort spiral.”  The Vera C. Rubin Observatory, a powerful, U.S.-funded telescope that recently began operation in Chile, could possibly observe individual icy bodies within the cloud. But researchers expect the telescope will likely discover only dozens of these objects, maybe hundreds, not enough to meaningfully visualize any shapes in the Oort cloud.  For us, here and now, the 1.4 trillion mile-long spiral will remain confined to the inside of a dark dome across the street from Central Park.