The need for energy performance targets

by Elaina Adams | December 1, 2012 2:55 pm

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By Bob Marshall, P.Eng., BDS, LEED AP
When it comes to the energy efficiency of its buildings, Canada is something of a paradox. On one hand, the country has received its fair share of accolades for green initiatives. For example, this author was in France in September for an International Organization for Standardization (ISO) TC205/TC163 joint workshop, and received laurels for coming from the world’s only nation with a holistic building commissioning standard—Canadian Standards Association (CSA) Z320-11, Building Commissioning. On the other hand, the country recently ranked 11 out of 12 on the 2012 American Council for an Energy-efficient Economy (ACEEE) International Energy Efficiency Scorecard. (Many design/construction professionals find this ‘scorecard’ a little unfair. For example, in the building codes category, Canada is deemed to have no insulation, window, or HVAC requirements, unlike the United States. This author knows most provinces have similar [and far more stringent) requirements to those south of the border, so the overall rating is inaccurate. For more on this, read the Construction Canada Online article, “Canada Poor Performer in Energy Efficiency Study.” Visit www.constructioncanada.net/newsletters[2] and search ‘ACEEE.’]).

Europe is often cited by North American sustainability experts as some sort of ‘Promised Land’ when it comes to energy-efficient design and green technologies. While there are indeed many glass towers on that side of the Atlantic, there are also higher-performance, energy-efficient building envelopes including vacuum-insulated panels (VIPs).

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Further, the Europe Union (EU) is mandating near-zero-energy buildings (NZEBs)—a common term for the performance of a building based on the calculated or actual energy it consumes, including from renewable sources. This energy performance is ‘cost-optimized’ to the lowest amount during the estimated economic lifecycle. Public buildings must comply with the Directive 2010 of the European Parliament by the end of 2018; all new buildings must follow suit within the two years thereafter. As Europe’s definition of ‘cost-optimized’ takes into account installation, operating energy, and maintenance at the member (i.e. country level), NZEB can be implemented as part of holistic building commissioning in North America to improve efficiency in Canada and the United States.

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For existing buildings (accounting for more than 95 per cent of the European stock), prospective buyers and tenants are now required to be provided with an Energy Performance Certificate (calculated according to a standard methodology) as shown in Figure 1.

Canada (or the United States for that matter) does not yet have a standard or code requirement for energy performance certification, but National Research Council (NRC) and the Standards Council of Canada (SCC) are working on ‘energy performance targets’ and an ‘energy performance certificate standard,’ respectively.

This article highlights the important work being done to raise Canada’s rank in ratings, shown in Figure 2, from red to green. The focus will be on the national codes and at the ISO level through SCC.

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Importance of energy targets
Canada has the highest energy use[6] intensity (EUI), which continues to rise in residential buildings, as shown in Figure 3. (Regarding the disparity in this map, the United Kingdom currently has more than seven million third-party energy-certified buildings to British standards, compared to Canada, which has no certified buildings and an unpublished standard.)

According to Canada Mortgage and Housing Corporation (CMHC), EUI is increased for high- and mid-rise apartments when compared to single-family houses (Figure 4). This is of concern given the growth of multi-unit residential towers in Canadian cities, along with the fact many of these newer buildings have inefficient glass walls with relatively poor building envelope durability.

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It is time for a new standard for energy performance to be combined with the existing building commissioning standard to result in energy cost savings and better rankings. North American buildings also need airtightness and high-performance insulation—such as the aforementioned VIPs with R-values of up to R-60 per inch (Figure 5). Efficient envelopes and HVAC, combined with renewable energy-producing systems integrated into buildings, can raise Canadian performance levels to NZEB status, as in Europe.

According to a recent survey by the North American Insulation Manufacturers Association (NAIMA), 70 per cent support mandatory energy labelling of houses. (For more, see “Ontarians Support Home Energy Labelling” at www.constructioncanada.net/newsletters[2]). In most of Europe, Energy Performance Certificates (EPCs) are required for all real-estate listings and rental units in order to provide transparency and consumer protection. Canadian experts are among those working on a similar ISO standard—Energy Performance of Buildings using Holistic Approach—that is based on British Standard (BS) EN 15217, Energy Performance of Buildings: Methods for Expressing Energy Performance and for Energy Certification of Buildings. It should be relatively easy to adapt for Canadian use upon its expected publication next year. For both new and existing buildings, this standard could be used to disclose energy use and enable homebuyers or renters to compare the energy consumption for different property listings. Consumers should be able to make better-informed choices once they know one home’s annual energy consumption is 335 kWh/m² and another is between 50 and 0 kWh/m² (F and A ratings, respectively, per Figure 6).

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The Canadian Commission on Building and Fire Code (CCBFC) approved the task of setting specific EUIs for buildings, which will likely be based on building occupancies. The NRC-established Task Force on Energy Targets is intending to release proposed EUIs for new buildings in 2013 to be incorporated in the 2015 National Energy Code for Buildings (NECB).

Establishing EUIs takes the current prescriptive energy requirements and allows a more flexible code compliance path to translate them into a quantitative performance target (i.e. ekWh/m2/yr). For example, large offices in Toronto (Climate Zone 5 per American Society of Heating, Refrigerating, and Air-conditioning Engineers [ASHRAE]) will have a proposed EUI of about 205 ekWh/m²/yr.

Toward NZEB with employing innovative systems
The 2011 NECB, along with provincial codes (e.g. Ontario and B.C. Building Codes [OBC and BCBC]) and various city ordinances (e.g. Vancouver), have created an opportunity for manufacturers to come up with innovative solutions in building envelopes. The current National Energy Code for Buildings aims to achieve 25 per cent less energy use than code requirements set in 1997 and the European Union goal of nearly zero. This provides fresh impetus for the next generation of energy-efficient insulating materials such as VIPs (Figure 7).

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Fortunately, there are VIPs developed in North America that can provide a 15 to 20 per cent R-value improvement and an estimated 10.5 per cent lifecycle cost (LCC) reduction with VIPs and double-pane windows in comparison with mineral wool and double-pane curtain walls for large, archetypal Canadian office buildings (Figure 8).

In this author’s opinion, VIPs and double-pane windows are the best LCC solution in Climate Zone 5, and should be considered not only in Ontario (where the Ontario Building Code has, since the start of 2012, mandated a 25 per cent improvement in energy efficiency over 1997 Model National Energy Code for Buildings [MNECB] for buildings), but also anywhere in Canada due to the low-LCC basis.

By integrating VIPs (with an average 18 per cent energy improvement) and the standard four-phase holistic commissioning process (with an estimated energy savings of 15 per cent), a total savings of about 33 per cent
can be achieved, though the savings are not exactly cumulative. This is better than the 25 per cent improvement required by OBC.

The U.S. Lawrence Berkeley National Laboratory (LBNL) discovered enhanced commissioning had energy savings of 13 to 16 per cent, with paybacks of 1.1 to 4.2 years. To achieve these higher performance targets, it is critical to integrate improved insulation, more efficient HVAC, and renewable energy-producing systems into the building at the pre-design phase.

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VIPs and renewable energy
VIPs can improve the energy efficiency of the building envelope and reduce up to 70 per cent of the emissions and energy costs. Its discrete ‘interior’ application makes it suitable for existing building stock, and can assist in projects looking to retain the cultural heritage of older buildings. Energy-efficient slim construction can be achieved by applying vacuum insulation panels or sandwich elements due to their low thermal conductivity.

At the University of Birmingham in the United Kingdom, VIPs were installed (as shown on page 40), with thickness of the panels optimized to 18 mm (0.7 in.) to achieve a 0.239 U-value W/m²-K in the spandrels. As part of building commissioning in the construction phase, a thermographic survey (Figure 9) confirmed there are no apparent defective panels; the product type seems to be working well, given significantly reduced heat loss recorded through the spandrel dual sealed insulating glass (IG) units and seals. (The areas highlighted in yellow show areas of warmth. These are due to trickle vents and rubber seals around the glass.)

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VIP systems are being looked at in Canada for learning centres, such as the new Halifax Central Library (Figure 10). In landmark projects in Europe, slim VIPs of 40 mm (1.6 in.) have been used to achieve the higher energy efficiency needed for NZEB. These assemblies have reduced the wall thickness from 240 mm (9.4 in.), essentially giving back 200 mm (8 in.) of interior rentable/saleable real estate. Innovative landmark projects are being sought in North America, especially at universities where there are education opportunities.

As VIPs are relatively new to Canada and internationally, it is critical to assess their application at the pre-design phase of building commissioning so schedules are not adversely impacted and innovative financial initiatives (e.g. Ontario’s GreenFit program) and NRC technical support can be considered. Natural Resources Canada’s (NRCan’s) Canmet and CMHC have also looked at continuous VIP behind an exterior cladding with a rainscreen drainage cavity in wood-framed housing (Figure 11). There are great opportunities to improve the energy performance of housing if the exterior cladding generated solar power, especially in high-EUI multi-family dwellings. Wood mid-rise residential buildings (For a discussion on residential green buildings, see this author’s article, “What are Canada’s Next Green Leaps?” in the September 2011 issue of Construction Canada[14]). with VIPs as an alternate to predominately all-glass structures could be an essential part of Canada’s goal of improved building energy efficiency and achieving cost savings.

As VIPs gain more market share, it is necessary to establish a standard for public safety and performance. At the aforementioned ISO meetings, SCC took a leadership role in assuming responsibility for development of a VIP standard.

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After higher building energy efficiency is achieved, use of renewable energy-producing systems must be considered for NZEB. There are key global developments of renewable energy systems that can be integrated into the glass, spandrel, and other panels on the façades. These solar glass panels are an alternate to adding photovoltaic (PV) panels on the roof, which requires additional structural supports and penetrations of the roof or, worse, are installed on valuable land.

This author investigated a promising solar power glazing in the United Kingdom (Figure 12) that could be made with different colour shadings and the solar film between the glazing generates renewable solar energy. According to a study completed for the University of Oxford, in the case of a 213-m (700-ft) skyscraper in Texas (Climate Zone 2) with 60 per cent of the façade installed with solar glass panels, about 5.3 MWhr of renewable energy would be produced daily.

It is also critically important for financial institutes and real estate trusts to embrace a European style policy with LCC considered in building upgrades and valuations. Taking into account rising energy costs for a 30-year LCC period would enhance the value of real estate portfolios and reduce long-term building operating costs. The 30-year LCC is shorter than the EU-permitted estimated economic lifecycle for the system, which could be, for example, a half-century for curtain walls. It is best to connect the economics of the system with the financial lifetime.

Conclusion
With energy performance targets, lower-cost lifecycle opportunities include insulation products and renewable energy options that can be analyzed as part of the commissioning process; overall costs can be reduced. One must measure energy performance to a uniform consensus standard to be able to manage the EUI and reduce consumption.

It is smart to act now on energy performance targets to see how existing or planned buildings compare with the coming codes and standards. Cost-optimal levels of energy performance that reduce EUIs can be implemented. True sustainability is about reducing energy costs and moving our buildings toward near-zero energy.

Bob Marshall, P.Eng., BDS, LEED AP, sits on the National Research Council’s (NRC’s) Task Group on Energy Targets. He is Canada’s appointed expert on the International Organization for Standardization (ISO) TC 163-TC 205 WG4 on Energy Performance, and the voting member for TC 163/SC 2 on calculation methods. Marshall chaired the U.S. Green Building Council’s (USGBC’s) Greenbuild 2011 ‘Best of Canada’ stream of educational seminars, and is a member of the council’s education committees. The founder of Cedaridge Services, he also provides senior consultant services to Stephenson Engineering based in Toronto. Marshall can be contacted via e-mail at bmarshall@stephenson-eng.com[17].

Source URL: https://www.constructioncanada.net/the-need-for-energy-performance-targets/

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