Lean and green
With the growth of the United States Green Building Council's Leadership in Energy and Environmental Design (LEED) certification program, no longer is it viable to merely install recycled carpet and label a building "green," or construct a grass courtyard and call a facility "sustainable." The comprehensive program requires that every aspect of a project-from what and where materials are selected to how to power the building-be analyzed with an eye towards environmental performance.
This more in-depth approach has opened the door to "outside-of-the-box" thinking when it comes to green design, leading to the implementation of new and creative green building technologies and sustainable design strategies.
From the elimination of air conditioning at Michigan Tech's new Dow Environmental Sciences building to the recycling of waste heat at Monsanto Co.'s Nidus Center for Scientific Enterprise, what follows are several examples of green buildings that employ the latest in green design.
Natural air all year in Michigan Tech building
Located in the heart of the upper Keweenaw Peninsula that juts into Lake Superior, the city of Houghton, Mich., is home to Michigan Technological University (MTU), a 6,000-student science and engineering school. As part of its "Initiative for the Environment" program to enhance environmental studies, the university constructed the 167,000-sq.-ft., $31 million Dow Environmental Sciences and Engineering Building to house its teaching and research departments. The nine-story building was designed not only to provide the proper facilities, but also to have a minimal effect on the environment.
A/ESmithGroup Inc.of Detroit implemented numerous sustainable design strategies, from the specification of materials indigenous to the region, such as copper, maple and oak, to the use of recycled steel in the structural frame.
A unique sustainable design feature is that the majority of the building does not have air conditioning. With the exception of several critical testing labs, the building relies upon outdoor air brought in through the central air-circulation system and operable windows to cool the interior of the building.
"The goal was to make the building as environmentally sensitive as possible while giving occupants control of their own environment," says Jeffrey Hausman, project manager for SmithGroup.
This approach is possible, even during summer months, because the outside-air temperature in the region usually cools down substantially at night and recovers slowly during the day, and the building's large mass and well-insulated exterior envelope help minimize mechanical design loads.
The exterior wall is a cavity system composed of 4 inches of brick, 2 inches of air space, 2 inches of insulation, a liquid-applied vapor retardant and 8 inches of block. The wall insulates interior space from outside heat or cold for up to 10 hours. Low-emissivity, argon-filled windows were specified.
To take advantage of the operable windows, all offices were situated on the perimeter.
Jack Yorke, senior engineer with SmithGroup, estimates that by eliminating air conditioning, the university saved as much as $750,000 in initial construction costs and is saving approximately $75,000 per summer month in energy costs.
Recycled heat reduces energy costs
Start-up companies researching new and marketable life-science technologies are finding a home at the Nidus Center for Scientific Enterprise in Creve Coeur, Mo. Sponsored by the Monsanto Co., the 42,000-sq.-ft., $9.7 million business incubator utilizes numerous sustainable features.
Most prominent is a heavily planted, two-story "living wall" in the atrium that filters air naturally. Daylighting through large windows in the labs decreases the demand for artificial lighting and louvers reduce heat gain while also reflecting daylight deep into the building. Moreover, a waste-heat recovery system recaptures at least 50 percent of total waste heat from the heating, ventilation and air-conditioning (HVAC) system.
"The waste-heat recovery system utilizes heat wheels that actually recover the heat or the cold going out of the building," says David Broughton, executive vice president of the Nidus Center. "It is then mixed with fresh air and passes over a heat coil. This approach recycles a great deal of the energy already used to heat or cool the building. It probably saves us in the neighborhood of 35 percent of our total energy costs."
The building also takes into account the larger significance of sustainable design by encouraging employees to use alternate transportation. Showers on both floors are for those who bike to work, and special parking spaces close to the building are reserved for those who carpool. The center also strives to limit its use of natural resources from the community. A case in point is its landscape irrigation system.
"We installed 3,000-gallon cisterns to catch the rainwater off of the roof," adds Broughton. "They cut down by about 50 percent the amount of water we would otherwise pull out of wells or public water systems for landscape irrigation over the course of a year."
Steel: A highly recyclable material
Utilizing a structural steel frame made of approximately 90 percent scrap steel, the Pennsylvania Department of Environmental Protection's (PDEP) Southcentral Regional Headquarters in Harrisburg, Pa., helps emphasize what the steel industry has for years been trying to convey: that steel is an environmentally friendly material.
According to steel industry sources, 88 percent of the steel taken from commercial construction demolition sites in 1998 was recycled and made into new steel products. The steel industry notes that by recycling steel products, it annually saves enough energy to power about 18 million households across North America for a year.
"When planning a green building, it's important to use materials that have significant recyclable content and are recyclable themselves at the end of their useful life," says James Toothaker, a bureau director at PDEP.
But the use of recycled structural steel was just the start of PDEP's sustainable design efforts in the three-story, 73,000-sq.-ft. headquarters. Other strategies included incorporating gas-fired absorption chillers that use water as the refrigerant, a dehumidification system that reduces cooling loads needs and an efficient lighting system that reduces the cooling load by an estimated 50 percent.
"The building is performing at about a 20-percent energy reduction over ASHRAE 90.1 1989 Standards," says John Boecker, principal with Kulp Boecker Architectsof Harrisburg, referring to the energy standard developed by the American Society of Heating, Refrigeration and Air-Conditioning Engineers.
Boecker says that he was able to use lessons learned from this project on Kulp Boecker's next building. "In that building, we were able to reduce energy consumption by 75 percent and energy costs by 50 percent," he adds. "This is a good example of how-as the green building industry takes off-building costs are lowered and energy savings become higher."
Building better buildings-on industrial by-product
When a brownfield site was selected as the location for the new 95,000-sq.-ft. Greater Pittsburgh Community Food Bank in Duquesne, Pa., the project team knew extensive site work would be necessary. Besides excavation to rid the 10-acre site of contaminated soil left by a steel pickling plant, the site also needed to be raised for proper drainage and leveled to support the new building. Also, much of the soil was not of structural bearing capacity.
"We had to find a fill material that would be capable of supporting a building pad," says Christian Klehm, president of Allison Park, Pa.-based Clearview Project Services Co., an environmental consultant to the project. Instead of soil or stone, a fill composed of industrial by-product was specified.
"The construction manager [P.J. Dick Co.of Pittsburgh] has a highway division that's been using this product to build up slopes for ramps and other big-fill roadwork projects," says Gary Gardner, principal of Pittsburgh-based Gardner+Pope Architects.
Comprising 95 percent post-industrial waste, the material is manufactured from an engineered cement and fly-ash deposits from the flues of a local coal-powered electrical generation plant.
"You simply spread and compact it like earth, and, as it's exposed to moisture and warmer temperatures, it hardens to a lean, concrete-like consistency," says Gardner.
Because the by-product is more similar in mass to concrete than to soil, says Klehm, it provides a much better thermal connection to the building's concrete slab than normal soil would, which steadies ground temperature swings. "It's like having a 5-ft.-thick concrete slab," adds Klehm.
The project called for approximately 20,375 cubic yards of the special fill at a cost of $40,750. "Because the material is primarily a waste product, we were able to purchase and deliver it for approximately $2 per ton, which essentially is the trucking costs," says Klehm. If dirt or stone fill were specified, Klehm estimates that it would have cost $244,500. The material was shipped from the utility plant just 8 miles away.
"Besides saving more than $200,000 by using a by-product that has good structural and thermal qualities," concludes Klehm, "we also diverted 20,000 cubic yards of waste material from a landfill."
Automated building lets occupants control their environment
Dedicated in March,Johnson Controls' $25 million, 130,000-sq.-ft. Brengel Technology Center in Milwaukee incorporates the latest in building automation and energy-saving technology. An advanced building-automation system (BAS) optimizes the efficiency of the mechanical and electrical systems while offering remote control of activities from turning off lights to starting the HVAC system. Lighting automatically adjusts to complement incoming natural light. To improve energy efficiency, a roof-mounted weather station forecasts system load.
While these systems aim to take ultimate control of the building's environment with the goal of balancing energy efficiency and comfort, some environmental freedom has been given back to individual employees through the use of workstation-based, individual controls for HVAC, lighting and white noise. Linked to the building's HVAC system via raised access flooring, the system provides each employee with desktop control of the temperature, lighting, airflow and acoustic characteristics within their own workspace.
"This system is an amenity that we can provide to our employees that lets them modify and tweak their own workspace," says Debrah Vander Heiden, manager of facilities planning for Johnson Controls, which manufactures the product. "For instance, the background noise generator helps muffle conversations and other noises typically found in an open-office environment, which has helped people coming from a private-office environment."
In addition to allowing control of background noise, the desktop control interface allows users to adjust under-desk radiant heat and task light levels. An air-mixing box and two desktop-level diffusers distribute a user-controlled mix of conditioned and ambient air.
Vander Heiden says that the company has saved energy, mainly because of a built-in occupancy sensor that automatically turns off the fan, lighting and equipment after an office is unoccupied for about 15 minutes. In addition, open areas like hallways now require less thermal conditioning.
Natural light + smart lighting system = energy savings
Adapted from a 1950s office building, Southern California Gas Co.'s 45,000-sq.-ft. Energy Resource Center in Downey, Calif., was designed with a mix of natural daylighting techniques and "smart" lighting technologies aimed at reducing energy costs.
Within the constraints of the former building, WLC Architects of Rancho Cucamonga, Calif., along with a team of environmental design consultants, worked to make maximum use of daylight. For instance, in a second-story addition, translucent window-wall sections were strategically placed to permit daylight to flood deep into interior spaces. According to Larry Wolff, principal of WLC, on a sunny day, natural lighting from the second-story windows can reduce electrical lighting needs by as much as 80 percent.
In addition, three skylights in the main first-floor corridor incorporate a sun-tracking system that utilizes mirrors, reflective light ducts and diffusing lenses to magnify incoming natural light. Each skylight system, says Wolff, can eliminate the use of more than two million watt-hours of electric lighting per year.
To efficiently supplement incoming natural light, several electronic lighting technologies were employed. Infrared occupancy sensors that automatically switch lights on and off are located within many enclosed rooms throughout the building. In rooms and areas with windows, light sensors continuously adjust the amount of electricity going to the fluorescent fixtures, depending on the daylight level.
Although the lighting system cost $200,000 more than a conventional system, it saves Southern California Gas between $21,000 and $30,000 annually in energy costs.
No flush, no problem
The Phillip Merrill Environmental Center Headquarters for theChesapeake Bay Foundation(CBF) sits on 31 acres of diverse habitat on the shores of its namesake waters. As home to the original "Save the Bay" organization-CBF and its 83,000 members are dedicated to protecting and restoring the health of the Chesapeake Bay, America's largest estuary-the 60,600-sq.-ft. facility is a living statement to developments in green construction, with numerous innovations.
So why is Charles Foster always asked about the toilets?
"We designed a rainwater catchment system that provides virtually all of our nonpotable water for the building," says Foster, director of fleet and facilities for CBF. "But actually, the first step in design was to look at conserving water in the first place. The no-flush composting toilets were a part of that, along with low-flow, automatic faucets and other water conservation features. The local press is obsessed with our toilets for some reason."
Waste from the composting toilets goes into a bin in the basement that allows the proper temperature and moisture for rapid decomposition. The end result is a waste product that looks and smells very much like topsoil that can be used as a nutrient-rich soil additive.
Other cutting-edge green technology includes building-integrated or directly connected renewable energy sources that provide about 30 percent of the building's energy load. These include geothermal energy, photovoltaics, natural ventilation, daylighting and solar water-heating systems.
"We have education centers around the bay, and have dabbled in sustainable construction in building those centers for about 15 years now," says Foster. "So this technology is not really new to us, we've just never put numerous technologies all together in the same building before."