Efficiency Starts Here

Want to get the best energy performance from a building? Work from the outside in Much of the talk about energy efficiency revolves around energy-using systems like lighting and HVAC. That's not surprising. After all, lighting and indoor climate control consumed 59 percent of primary energy used by the commercial sector in 2002, according to the Center for Sustainable Systems at the University of Michigan.

But when a new building is being designed, the interior is the wrong place to start looking for energy-saving opportunities. Instead, energy should be foremost in facility executives' minds when the building envelope is being planned.

"You start with the envelope, and try to conserve as much as you can before you start spending on the mechanicals," says Tom Hootman, director of sustainability with RNL in Denver.

Of course, that's easier said than done. In a traditional design and construction process, aesthetics is the primary consideration when the exterior is being planned, with energy efficiency as an afterthought. But to a significant extent, the exterior determines the heating and cooling loads, as well as the amount of electrical lighting that will be needed. So if the design of the building envelope neglects energy considerations, the building will use more energy than it might have, even if the facility executive invests in the most energy-efficient HVAC and lighting systems available.

Today, a growing number of projects reflect the energy benefits of paying careful attention to the building exterior. One reason is greater concern for energy and green buildings. But the emergence of computer applications that can reliably model estimated energy use under a range of scenarios is making it easier to create energy- efficient exteriors. A

Technology is also playing a role. For example, the quality of energy-efficient materials, such as high-performance window glass, has improved. And a simple understanding of the role of the exterior has led to increased use of measures such as reflective roofs - an energy-saving technology that may add nothing to the cost of a new building.

Building codes in a growing number of states and municipalities are also leading facility executives to pay more attention to the building exterior. In some cases, that's because codes mandate steps like the use of reflective roofs. Beyond those specific requirements, tighter code limits on overall building energy use are leading facility executives to pay more attention to the exterior as an opportunity to reduce the amount of energy the building consumes.

Civic and Justice Center

A first step toward energy efficiency is orienting a building so that heating and cooling by the building systems can be minimized, Hootman says. That strategy was used the Civic and Justice Center for Commerce City, Colo. Within the constraints of the plot available, the design minimized the portion of the building that would be exposed to the west and thus vulnerable to solar heat gain. Due to the shape of the lot and the activities that occur inside the 90,000 square foot facility, which opened in 2007, it contains some western exposure.

To compensate, a dozen different glazings were used on the Center's windows; the glazing chosen varied with the heat gain a window received, as well as the space behind that window. For example, the upper portion of windows that lead into office spaces contain daylight glass that disperses sunlight across the ceiling, rather than letting it pour directly down to occupants' desktops. On the other hand, the lower portions of the office windows are made of high performance glass that lets in light, but not heat. Sun shades were incorporated into all south-facing windows to reduce heat gain and glare.

To further reduce energy consumption, the Center installed more insulation than required by code. For instance, the insulation value of the roof is R30, or about twice the code mandate, Hootman says. In addition, the roof membrane is white, and reflects heat - preventing it from entering the building.

These measures, along with the use of energy-efficient building systems and lights, have cut energy use by about 33 percent, for annual savings of more than $50,000 when compared to ASHRAE 90.1- 2004, Hootman says. These figures are based on energy models, as the Center has not been operating long enough to provide meaningful energy use statistics.

The Brewery Blocks

The Brewery Blocks project in Portland, Ore., is a mixed-use project covering about 1.7 million square feet. The facility, developed by Gerding Edlen Development, consists of two residential and three office buildings, as well as a performing arts center. "We understand the effect of the building's facade on the mechanical system," says Bruce Brown, principal with GBD Architects.

The window glass in the Brewery Blocks varies depending on the solar exposure of the window. In addition, some of the windows can be opened several inches. When an occupant opens a window, he or she also can shut off the mechanical system near the window. That way, the building gets fresh air, but heating or cooling isn't wasted. "We have a temperate climate, so natural ventilation strategies can be pretty successful," says Rene Worme, spokesperson with GBD.

Several eco-friendly features are found on the project's rooftops. Brewery Block Four, for instance, sports photovoltaic panels that will generate enough electricity to save about $1,500 per year. A portion of the fourth floor roof setback is planted with vegetation native to the area. In addition to enhancing the green image of the project, the "eco-roof " will attenuate storm water run- off. The roof will handle about 320,000 gallons of water each year, according to GBD.

The rooftop garden is an integral design element of the building, Brown says. Many town homes look down over the eco-roof, giving occupants a much more aesthetically pleasing view than a black or ballasted roof would have.

Construction costs for Block Four's eco-friendly features boosted overall costs by about one percent. However, energy models show that the high-performance building envelope, along with energy efficient HVAC systems, should cut energy costs by $58,000 annually, for a payback period of about 8.5 years, GBD says. Block Four received certification by the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED) program.

Visitor Center, Fullerton Arboretum

The Visitor Center at the Fullerton Arboretum, at California State Universify-Fullerton, is designed to take advantage of the westerly breezes that blow in from the ocean and across campus, says Brian Dougherty, project architect and partner with Dougherty & Dougherty. To accomplish this, the windows and roof on the west side of the building are lower, while those on the east side are higher. "It's like an airplane wing," Dougherty says. "Air goes over the roof and creates a vacuum that draws hot air out of the classes, and then draws in cool air."

Double-pane windows further boost the energy efficiency of the 8,500square-foot-building, which opened in March 2006. The use of two-by-eight beams, rather than two-by-fours, allowed for more insulation, says Michael Craig Smith, director of design and construction with the university.

Between these design elements and the variable speed ceiling fans installed in the Arboretum's classrooms, airconditioning and heating is needed only on very hot or cold days. "It's very comfortable without HVAC," says Smith.

New Haven School District

Even small energy savings add up quickly when they're multiplied by 40 or more facilities. That's one reason the New Haven School District, New Haven, Conn., began implementing energy efficiency measures in its elementary, middle and high schools, says Thomas Roger, vice president and project executive with Gilbane Building Company, the program manager for the $1.05 billion rebuilding effort. "If the buildings are not built to operate efficiently, you won't have money to run them," he says.

The program, which is scheduled for completion in 2012, will provide the city with 37 renovated and six new school buildings. As of early 2007, five of the high-performance buildings were operating, and another 10 were in the pipeline.

The district is using conventional construction techniques, while dramatically boosting its use of materials that can conserve energy, Roger says. "The roofs and walls far exceed ASHRAE standards." The district is using R15 wall insulation, compared to the R7 value called for by ASHRAE. Similarly, the roof insulation is 12 inches, versus the more conventional 6 inches. The windows are made with glass that features U-values of .3, versus the .75 U-value allowed by ASHRAE.

Energy use within the renovated buildings has dropped to less than half what it was before the upgrades - including insulation and windows were put in place. An analysis of utility bills shows that the average building in the district previously used 250 BTUs per square foot; that compares to less than 100 BTUs per square foot in the energy-efficient buildings now. The insulation contributes about 20 percent of the savings, Roger estimates.

Envelope Challenges

While incorporating energy efficient designs and materials into a project can reduce energy use, it also creates challenges. Brown, the architect behind the Brewery Blocks project, notes that using elements such as photovoltaic panels requires incorporating them into the overall design of a facility. "You have to integrate it so that they don't look like a TV antenna plopped on the building." Completing an energy-efficient building also requires an integrated effort between the designers, engineers, contractors and others involved in the project. For example, if any particular aspect of the design is new for the designers and engineers, it's critical to discuss the challenges during project meetings. This will allow team members from other areas to offer their perspectives and keep the project on track and moving forward.

Some projects require working with local officials. When management at a New Jersey bank installed a solar roof, they had to address the fire marshall's concern that, if a firefighter needed to cut through a panel during a fire, the electricity generated by the panel would cause a shock. That's not the case, as each panel individually generates a small amount of electricity, and the firefighters' saws are insulated against higher electrical voltage.

As more energy-efficient buildings get up and running, and more builders, inspectors and others involved in the process become familiar with them, these issues are likely to occur less frequently.

Down the road, the focus will shift from designing buildings that are energy efficient to creating buildings that actually help the environment by, using less energy than they generate, says Dougherty. "We're talking beyond green," he says.

The 1.7 million square-foot Brewery Blocks facility in Portland, Ore., uses different glazing on different exposures to customize each for the sunlight it will receive.

GREGG GALBRAITH, RED STUDIO INC.

LEARN MORE ONLINE

Go to www.facilitiesnet.com/6987bom to read more about energy- efficient exteriors:

* Solar roof panels at a bank

* The role of the windows and roof at a visitors' center

* Tax deductions for energy-efficient exteriors under the Energy Policy Act (EPAct) of 2005

BY KAREN KROLL, CONTRIBUTING EDITOR

Karen Kroll, a contributing editor for Building Operating Management, is a freelance writer who has written extensively about real estate and facility issues.

E-mail comments and questions to edward.sullivan@tradepress.com.

Copyright Trade Press Publishing Company Jul 2007

(c) 2007 Building Operating Management. Provided by ProQuest Information and Learning. All rights Reserved.