Here’s what you can use about buildings producing all the energy they use
Net zero buildings are highly efficient structures that produce as much energy as they use. The zero-energy design principle is growing in importance due to increasing costs of traditional fossil fuels and their negative impact on the planet’s climate and ecological balance. It’s entirely possible to construct a building that produces enough of its own power that it does not consume energy from the grid. An energy-plus building can even produce more power than it consumes, converting it into a mini power plant.
The following 10 things will tell you more about migrating to net zero buildings.
1. Why bother with buildings?
Commercial and residential buildings consume about one-third of the world’s energy. In the United States, buildings account for more than 40 percent of total energy consumption, including 72 percent of electricity generation, 12 percent of water consumption and 60 percent of all non-industrial waste.
According to a report by the National Science and Technology Council Subcommittee on Buildings Technology, Research and Development, if current trends continue, by 2025 buildings worldwide will be the largest consumer of global energy, more than the transportation and industry sectors combined.
2. Push the envelope.
Metal building systems have higher air leakage compared to other types of construction. Without focusing on their underlying metal building envelope design and incorporating high R-value continuous insulation to produce an air-sealed solution, achieving net zero success will be very difficult or inefficient. New ASHRAE 90.1 energy codes require building designs to comply with air infiltration requirements. Individual materials must have a maximum air permeance level no greater than 0.004 cfm/ft2. Additionally, building systems or assemblies must have a maximum air permeance level no greater than 0.04 cfm/ft2.
By adding a continuous blanket of insulation, and sealing additional junctures and penetrations in the building envelope with foam sealants, a significant reduction in heat loss can be economically realized. This heat loss would otherwise have to be accommodated by additional energy-generating technologies, such as solar panels.
“In a metal building, thermal shorts reduce the R-value of cavity-insulated wall systems by more than 50 percent,” says Doug Todd, market manager of commercial construction at Dow Building Solutions, Midland, Mich. “Installing a layer of high R-value continuous insulation over the steel studs reduces the impact of the highly conductive steel. For example, 1/2-inch-thick board R-3.0 THERMAX insulation has the same thermal resistance equivalency to 10 feet of steel, close to 250 times more effective.”
But insulation is not enough, especially in a net zero building. If the building envelope leaks air, the overall impact of the insulation is compromised.
“Dow has identified cost-effective, field-tested methods to detail the insulation as an air barrier using tapes, PVC joint clips, insulation edge treatments, construction grade sealants and adhesives, and air sealing foams such as FROTH-PAK Foam Insulation and GREAT STUFF PRO Insulating Foam Sealant,” Todd says.
3. Insulated panels are a plus.
Walls have been insulated for centuries, ever since animal skins were first hung on rock walls or sod huts were crafted with thick dirt walls. Today, insulated metal panels (IMPs) aid net zero efforts by producing an airtight, moisture-resistant, rigid, continuous-insulation solution. IMP’s high R-values provide superior thermal performance and reduced energy consumption. This allows for smaller greenhouse gas emissions and reduced energy costs for building owners, which contribute to net zero success.
IMPs mitigate thermal drift, a degradation of R-values over time. Thermal drift is common when using un-faced polyisocyanurate rigid board insulation, which can lose up to 20 percent of its R-value within two years.
IMPs can be integrated with other building envelope solutions, such as windows, louvers and sunshades, to further push toward net zero. IMPs can be coated with cool roof colors, which offer potential energy savings throughout a roof’s lifetime. This helps mitigate the urban heat island effect in urban areas.
Research has shown that today’s insulated wall and roof systems can save as much as 30 percent of a building’s total energy use. An independent simulation analysis was performed by the Architectural Energy Corp. to evaluate the energy efficiency impact of improving typical buildings with IMP wall and roof systems. Three baseline buildings compliant with ASHRAE Standard 90.1-2004 and 90.1-2007
(school, office and warehouse) were simulated in four locations. Each building’s envelope was improved with the IMP wall and roof systems.
4. Concentrate on energy conservation.
Energy conservation will always be a critical component in net zero buildings. By reducing the energy base load by deploying energy efficient building technologies, the need for renewable energy production is significantly reduced.
In terms of energy conservation, lighting is one of the most important components. According to a U.S. Department of Energy
(DOE) report, lighting accounts for about 20 to 50 percent of the entire electricity consumed by U.S. residences and offices.
New light-emitting diode (LED) fixtures have surpassed fluorescent and mercury-based lamps in delivering energy reduction and provide the most environmentally sustainable solution. LED fixtures offer a durable, sustainable, low-energy choice. “LED fixtures are 65 percent more efficient than high-intensity discharge (HID) fixtures, and 30 percent more energy efficient than fluorescent ones,” says Jeff Bisberg, co-founder and CEO of Albeo Technologies in Boulder, Colo.
“By adding smart controls, such as automatic on/off motion sensors, energy use can be cut even further. Dole Foods documented a reduction in its lighting energy use by up to 95 percent at its Atwater, Calif., sub-zero cold storage warehouse, through Albeo LEDs and smart controls.”
5. Daylight is an efficient source.
Lighting accounts for 25 percent of total energy usage in a typical U.S. office building and waste heat generated by artificial lighting contributes significantly to the total cooling load. Both of these facts make optimizing natural daylight and controlling artificial lighting, critical components in achieving net zero buildings. Daylight is the most efficient lighting source.
To fully take advantage of lighting as a net zero input, buildings should be oriented on sites correctly to maximize the amount of windows in a building. Designers can save energy by optimizing natural daylighting, gaining passive solar heat in winter and minimizing solar heat gain through windows.
Steve Fronek, PE, LEED Green Associate and vice president of technical services at Wausau Window and Wall Systems in Wausau, Wis., believes when aiming for net zero, “window or curtainwall manufacturers should have a
‘seat at the table’ to leverage their intimate knowledge of system capabilities, trade-offs and costs. Interestingly, the most basic properties of glazing system-size and configuration-can be the most impactful.”
To further maximize the power of the sun,solar panels can convert solar radiation to electrical energy. Net zero buildings generally require a suite of several solar panels to supply an adequate amount of energy. Photovoltaics’ zero-emission energy reduces greenhouse gases and pollution. Solar technology is constantly evolving with increased efficiencies and energy storage capabilities.
6. Cheaper than you think.
Net zero energy commercial buildings are both more feasible and affordable than people think, so says a report from the New Buildings Institute (NBI) and the Zero Energy Commercial Building Consortium (CBC).
The report is titled “Getting to Zero 2012 Status Update: A First Look at the Cost and Features of Zero Energy Commercial Buildings.” According to it, the incremental costs for net zero building energy efficiency features range from 3 to 18 percent, depending on building type, size, climate and other variables.
As the larger office buildings market moves toward net zero, minimizing electrical loads from plug-in equipment and appliances, along with other miscellaneous or “unregulated” loads is a priority, the report says. The emergence of new technologies will also be a factor in expanding to more building types, NBI says.
Adopting these new energy-saving technologies may have high initial cost implications, but the ROI these costs bring is quick and the reduced energy savings last for many years afterwards. “Our customers have reported ROIs in as short as 18 months to a maximum of three years for LED purchases, depending on the application of the LEDs and the use of the building,” Bisberg says.
The key to selling the net zero idea is moving building owners from a commodity to a value-based mindset. “Have them focus more on the ROI many of these technologies bring and value the long-term cost savings more than the short term, up-front costs of analysis, products and construction,” Bisberg adds. “Additionally, there are the marketing and’good will’ publicity benefits that society attaches to a company that is visionary enough to construct a net zero building at this time, verses a conventional building or even a LEED one.”
7. Earlier is better.
When aiming for net zero, earlier is better. The greatest potential for savings and the most cost-effective strategies often originate in building design. Whether conceiving a building to make use of appropriate solar orientation, or land use planned to minimize transportation distances, a manufacturing process development that includes minimizing energy use, it is in the design stage that highly cost-effective strategies for making an impact are selected. Furthermore, such options, when ignored, represent “lost opportunities” that are impossible or cost prohibitive to achieve later in a project’s life.
It is in the design stage when the energy performance of and interaction between interrelated building components creates opportunities to build net zero buildings economically. Integrating building component energy performance creates tradeoffs that can pay for substantial performance improvements without dramatically increasing cost to build. This is what is commonly called a “whole building” approach to design.
“Unfortunately, for many contractors this whole building design approach takes them out of their comfort zone, as they rely heavily on individual suppliers for recommendations and design advice, and the suppliers may not be excited about making trade-offs that reduce their share of the project,” says Justin Harkins, national sales manager at Thermal Design Inc., Stoughton, Wis. “As a result, attempts at net zero buildings are often limited to very high-end projects that can budget for substantial independent engineering costs.”
Thermal Design offers Simple Saver SynergyDesign services to metal building contractors that allow them to perform rapid design analysis, make design tradeoffs, estimate cost differences, calculate energy savings, simulate energy consumption, and facilitate energy related government and utility incentives for the project.
8. They’re becoming required.
The California Energy Commission (CEC) is requiring residential buildings in California to be net zero energy by 2020 and commercial buildings by 2030.
California’s action plan offers common-sense strategies for moving the market toward net zero energy performance. Raising minimum energy performance through codes, expanding energy codes to address all energy end uses, developing financial tools for supporting net zero energy construction, and supporting integrated design are all mentioned as strategies for new construction. For existing buildings, the action plan suggests tightening code thresholds, requiring energy and carbon emissions labeling, and supporting occupant feedback and training. Several California utilities are already working on pilot projects and local governments are already adopting standards more stringent than the state standards.
A number of countries and regions have already established long-term targets and regulations requiring zero energy building construction that will come into effect over the coming years, some as soon as 2016. In the European Union, a March 2009 resolution requires that, by 2019, all newly constructed buildings produce as much energy as they consume on-site. These stringent regulations will accelerate adoption around the world, causing the industry to undergo a significant transformation in the coming years.
According to a new report from Pike Research, worldwide revenue from zero energy buildings will grow rapidly over the next two decades, reaching almost $690 billion by 2020 and nearly $1.3 trillion by 2035. That represents a compound annual growth rate of 43 percent, with much of that growth occurring in the European Union.
“Following the surge in LEED and other green building certifications worldwide over the last few years, zero energy building has emerged as the ‘holy grail’ in green building design,” says research analyst Eric Bloom. “Technically, zero energy building design is feasible for many building types in many regions, but concerns about the upfront cost continue to impede it in the market.”
9. They’re becoming certified.
The International Living Future Institute has a new green building certification program it will administer for net zero energy use. There has never been a certification program for net zero buildings prior to this.
The net zero certification is based on actual building performance rather than modeled outcomes. Buildings must be operational for at least a year prior with proven results prior to being certified. Certification verifies a net zero building is truly operating as claimed, harnessing energy from the sun, wind or earth to exceed net annual demand.
It’s one thing to say a building is zero energy; it’s another thing to prove it. Certification provides a platform for the building to inform other efforts throughout the world and accelerate the implementation of restorative principles. Certification celebrates this significant accomplishment and differentiates those responsible for the building’s success.
10. There’s help out there.
To learn more about attaining net zero building success, the Design Lights Consortium is a good source for high-quality, energy-efficient, commercial lighting design and information. It offers a qualified products list with current LED lighting fixtures and their ratings at www.designlights.org. Deland, Fla.-based Kingspan Insulated Panels Inc. has two tools, EnvelopeFirst energy efficiency and Path to Net Zero, to aid in attaining net zero.
“We help optimize the envelope with a performance model on selected projects; and then we provide a total envelope solution: including photovoltaics on our standing seam roof,” says Paul Bertram Jr., FCSI, CDT, LEED AP, and director of environment and sustainability at Kingspan. “The core product lines are highly insulated wall and roof panel systems with integrated openings, including for windows, doors and more. And the photovoltaic panels are offered also, so it’s basically everything you need for net zero.”
Wausau Window and Wall Systems offers an online “Green Product Selection Tool” at http://www.wausauwindow.com intended to provide a one-stop, visual reference to help users rank and compare performance information and potential energy savings. This tool allows users to choose from eight cities to view performance data between a set of Wausau products for either new construction or renovation projects. Visitors can gather performance information on annual energy, peak demand, carbon emissions, daylight, glare, condensation and cost savings.
The DOE’s Energy Efficiency Renewable Energy website, www.eere.energy.gov/buildings/betterbuildings, has information for contractors related to building net zero buildings. The DOE’s Net Zero Energy Commercial Building Initiative
(see sidebar) is a valuable program for a better understanding of how to achieve net zero today. At www.DSIREusa.org, users can look for renewable energy incentives from federal, state, county and utility sources. “For upgrading a building, the Energy Policy Act provides tax credits up to $1.80 per square foot until December 2013,” Bertram says.
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Delve into a net zero database
The U.S. Department of Energy’s Zero Energy Buildings Database features profiles of commercial buildings that produce as much energy as they use over the course of a year. In this database, users can learn more about diverse net zero projects and gain ideas that can be applied to any new building. By simply clicking on a net zero building’s name, users can view in-depth information about a project’s design and construction process, financing, energy use, materials, indoor environment and more. This database is part of the High Performance Buildings Database, which lists many additional projects where users can discover more energy-efficient building techniques.
The database collects information from buildings around the world, ranging from homes and commercial interiors, to large buildings and even whole campuses and neighborhoods. These may be certified green projects, or simply projects that have one or more notable environmental features. The information has been reviewed for consistency and presentation, but in most cases, the details have not been independently verified. For more information, go to
zeb.buildinggreen.com.
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The occupant and the owner
The energy used in a building can vary greatly depending on the behavior of its occupants. The acceptance of what is considered a comfortable climate varies widely. Studies of identical businesses in the United States have shown dramatic differences in energy use, with some using more than twice the energy of others. Occupant behavior can vary from differences in setting and programming thermostats, varying levels of illumination and hot water, and the amount of miscellaneous electric devices or plug loads used.
Because the energy consumption profile of a very low-energy building differs so much from conventional buildings, building operation and control become very important in hitting net zero goals. “Automated controls are essential for implementation, but it is still important to work with the owner on an operational plan up front as part of the implementation of a low or net zero energy building,” says Justin Harkins, national sales manager at Thermal Design Inc., Stoughton, Wis. “The operational plan must be realistic, meet the owner’s business needs, and have a clear plan for occupant cooperation with implementation.”
