Glass and the 2030 Challenge: Exploring experimental glazing strategies

Images courtesy Mark Driedger
Images courtesy Mark Driedger

By Mark Driedger, LEED AP
For the past 100 years, developers and architects driven by the Modern movement have designed skeletal boxes skinned with glass for beauty and simplicity. Natural light, the diminishing of separation between interior and exterior, and open working environments were the result of these experimental glazing assemblies. This strategy continues to spread throughout the globe, in all climates.

In many ways, giving an increased focus on form over function has hurt the architectural profession. While a building may be designed to meet the needs of its human inhabitants, very rarely is it designed to perform efficiently within its environment.

In Canada and the United States, most architectural schools’ are focused on the obvious design esthetics and its inner works, with very little training dealing with the realities of building science or engineering. Rules of thumb, such as south-facing glazing, passive solar, and daylighting, are implemented in students’ designs as if they were following a checklist. Unfortunately, they have few ways to ascertain the performance of their decisions. Even prominent buildings, certified to the Leadership in Energy and Environmental Design (LEED) standard have trended in this direction—as a result, they often do not perform as efficiently as promised or planned.

The functional building science equations have been shifted almost entirely to arm’s-length consultants who are to assist the architect in their specialties (e.g. envelope, energy modelling, etc.). The list of consultants required by an architect seems to grow each year, which can water down their value to the public. In many cases, architects have been gradually losing the tools to truly understand anything beyond esthetics. As some have said, “We are becoming exterior designers.”

Some of the responsibility of the resulting design malaise may be twofold. Architects are typically not pushed to create energy-efficient buildings by their clients, as capital costs are a priority. Secondly, Canada enjoys—for the time being—a plentiful supply of natural gas supplying the majority of comfort energy. However, as awareness of our carbon footprint grows, the liberal use of natural gas may also change.

Figure 1: This graph shows a comparison of building energy intensity by decade, compiled by Natural Resources Canada (NRCAN). It comes from a December 2013 statistical report.

Climate factors
In a typical Canadian building, much more energy is expended in heating than in cooling. However, because our electricity pricing and the inefficiencies of the cooling processes, the annual cost of cooling can exceed that of heating in the warmer areas of the country.

In the last 10 years, the push to become more energy-efficient has been limited or even stagnant. Figure 1  shows the energy-use intensity (EUI) of Canadian buildings constructed in the last few decades. This chart illustrates the lack of progress in reducing the country’s energy usage.

ATA Architects, located in the Greater Toronto Area (GTA), has begun the slow process of stepping away from this approach of delegating energy-based decisions to consultants. The 2030 Challenge, which is pushing for new buildings to be carbon-neutral by that year, is only a decade and a half away. Building codes and governing bodies are now reducing buildings’ glazing percentages and exchanging them for solid wall systems that have drastically superior insulation values. Software tools such as Autodesk Green Building Studio and Sefaira can link with building information modelling (BIM) at the early design stages to help understand the effects of forms.

The 2030 Challenge is very difficult for an architect in a cold climate; presently, Canada is quite far from this goal. The average annual EUI for an office building in the country is around 1.20 GJ/m2 or 333 KW h/m2. (The information from this chart is derived from Natural Resource Canada’s [NRCAN’s] Survey of Commercial and Institutional Energy Use Buildings [SCIEW]. Visit www.nrcan.gc.ca/energy/efficiency/buildings/energy-benchmarking/update/getready/16731). Drastic energy reduction methods need to be employed, and this energy should subsequently be offset with alternatives such as mass implementations of photovoltaics (PVs) to meet the 2030 Challenge. Considering the lack of sunlight in cold climates and the low efficiencies of solar panels, this is an epic mountain for cold climate architects to climb. Theoretically, by 2030, all new buildings are to be off the grid from an energy standpoint.

Heating typically represents the largest energy use for a building in a cold climate. In a Toronto winter, the contrast in temperature between outside and inside can be upward of 40 C (72 F). With a temperature differential that large, even the best-performing insulated glazing (IG) units become huge exposed radiators for the building. These units perform better in the summer and in temperate climates, where the differential is typically only around 10 C (26 F).

Temperate climates have a distinct advantage over cold climates because they have low interior/exterior temperature differentials. This means they will also have a much easier time achieving net zero. A larger temperature differential means more energy is required for the HVAC system to overcome the differential. Strategically placing windows and reducing window area is the best solution in cold climates.

Glazing is typically the largest energy loss for a building. Canada’s frequent lack of sunlight in the winter drastically lowers the returns of passive solar. Unless carefully planned, architects cannot count on glazing assisting with heating in the winter. Since building codes generally dictate the minimum fenestration required, eliminating windows becomes difficult. A good compromise is to provide the passive option through orientation. In this case, some passive pluses are possible on the few sunny days the country does have.

It will take innovations in all design and construction aspects for cold climate buildings to achieve the goals of the 2030 Challenge. Architects have traditionally been at arm’s length when it comes to research and innovation. New software packages and cloud computing have allowed even small firms to experiment and are changing this notion. Rather than constructing full-size test models and hot boxes of new strategies, computational fluid dynamics (CFD) software other industries have been using for decades can now
be employed.

There will be few ‘game-changing’ ideas when it comes to achieving the goals of the 2030 Challenge. Most strategies will result in many small percentage efficiencies, collectively serving to increase the performance of today’s technologies.

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