August 11, 2010

MEP Technologies for Eco-Effective Buildings (Continued from p. 48 of the July 2009 issue of BD+C)

Motorized systems. It may seem paradoxical, but the use of motorized systems can sometimes enhance sustainable design, even while adding some upfront cost and incremental power load.

For example, while the use of window shades and blinds—a long-standing solar shading strategy—may be routine these days, the integration of controls with such products is quickly catching on. “Motorized shades, when used correctly, can decrease the heat load significantly on a building’s spaces that may see large fluctuations in direct sun heat loads,” says TLC Engineering’s Fryman. “With more competition, the upfront cost has come down, making these systems more viable.”

Furthermore, sophisticated control systems offer additional capabilities for motorized solar control, as Kensky explains: “Central systems can automate the controls for responding to sunlight exposure changes throughout the day and through seasonal changes. For example, nighttime winter operation lowers the shades to provide additional insulation, if desired, and nighttime summer operation raises the shades to assist in nighttime cooling.” 

                           
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When specifying such products, Papademos advises choosing the appropriate type of shade, selecting a shade with compatible aesthetics, and specifying a system that can easily be integrated into the building management system (BMS). In fact, says Fryman, motorized shade systems need to be carefully integrated into the overall building design in early schematics. “The building orientation to the sun, interior lighting and glare possibilities, and power and controls for the shades and lighting must be incorporated to achieve the best results for the space application,” he says.

Kesler warns, however, that proprietary shade and motor control packages can add to installed costs and may lead to ongoing maintenance problems.

Photovoltaics. It’s impossible to discuss building electrical efficiencies without discussing solar power, which is why so many Building Teams at least consider the use of photovoltaic (PV) arrays or building-integrated PV (BIPV) materials for green projects. And while R&D into PV systems is progressing, with more efficient and larger aesthetic variety coming to the market, “First cost still remains at a point where the PV systems that do get installed are justified for reasons other than straight economics,” says Steven Eich, PE, LEED AP, vice president, Environmental Systems Design, Chicago. These include grants and incentives to offset the first costs. Moreover, the use of PVs in a project makes a powerful environmental statement that remains associated with the building.

On a technical level, other benefits of photovoltaics include the following:
• PV energy is generated and consumed at the same location, eliminating transmission line losses.
• PV systems offset pollutants such as nitrogen oxide, CO2, sulfur dioxide, and nuclear waste.
• BIPV systems can replace other building elements like glazing or spandrel panels.
• BIPV and roof-mounted solar-power systems can provide shade that will reduce a building’s cooling load.
• PV modules can be used as window shades or fins to reduce solar heat gain.




Still, PV first costs are high, and the typical payback is very unattractive at 20-25 years. However, some experts say that government incentives will change this. In fact, according to Brandy A. Chambers, LEED AP, an engineer with R.G. Vanderweil Engineers, Boston (www.vanderweil.com), a 30% federal tax credit is available to virtually all photovoltaic projects, and many states have additional incentives. For example, the Massachusetts Technology Collaborative offers additional rebates on systems up to 500kW in size, and the New York State Energy Research and Development Authority offers rebates on systems up to 50kW in size, in addition to a state-offered tax credit, according to Chambers.

In addition, more and more building owners are availing themselves of power purchase agreements. “Through this arrangement, an independent third party installs an array on to the interested party’s property, but retains ownership,” explains Chambers. “The property owner then agrees to buy the electricity that the array produces at a fixed cost per watt, which is typically lower than utility-supplied electricity. The owner also benefits by avoiding the potential headaches involved in financing and maintaining the array.”

Building product manufacturers are also offering new products and services for solar energy projects. For example, Tecta America (www.tectaamerica.com), a Skokie, Ill.-based roofing contractor, recently launched a solar division offering a comprehensive turnkey package, including design, engineering, financing, installation, maintenance, warranty, and monitoring performance of solar installations.

Power-generating switches. At a large scale, photovoltaics are a compelling way to return power to the grid. At a much smaller, more local scale, new electrical gadgets are helping end-users save energy and even return some to their own buildings through smart product design.

Among the more unusual offerings of this type is a new light switch that actually generates power through the act of switching it on. Capturing the kinetic energy created by this motion, one device powers its wireless signal (which can be transmitted up to 300 feet) to dim, turn on, or shut off incandescent and dimmable compact fluorescent lights. “It is a great solution that delivers truly green lighting projects,” attests Alan L. Bravo, principal and project director, FBA Engineering, Newport Beach, Calif. (www.fbaengineering.net), who has specified the light switches for a number of projects.

Bravo also likes the fact that the wireless product eliminates the problem of routing new conduit for retrofits. “This solution allows for the easy placement and relocation of wireless light switches and solar powered photosensors on any surface, which solves a lot of problems,” he says. The product also offers greater flexibility for the future, and does not require batteries. “This makes it very appealing from a maintenance standpoint,” he adds.

A related product developed by researchers at the LBNL’s Environmental Energy Technologies Division (http://eetd.lbl.gov/), called WiLight, also harvests the mechanical energy created when the user clicks on the switch. This energy then powers a wireless signal either when the occupant desires to change the light setting or in response to building-wide demand.

             
Dimming ballasts, daylight sensors, and motion sensors reduce artificial lighting needs at Great River Energy. The new headquarters harvests daylight through narrow office floorplates and multiple light-filled atriums. With reduced lighting requirements, less heat is generated, lowering the need for air conditioning. The building uses 40% less energy for lighting than similarly sized buildings that use standard technology. Photo: Lucie Marusin, Courtesy Perkins+Will
            

According to LBNL spokesman Allan Chen, the WiLight system can also be integrated with another LBNL technology, the client logic integrated relay (CLIR), which enables buildings to monitor the status of the electricity grid over the Internet, via signals from utility servers. “If the grid nears an overloaded emergency state, the CLIR box uses the WiLight radio bridge to send a radio frequency signal to the building indicating the seriousness of the crisis. Nonessential energy uses are reduced—for example, building lighting levels—as WiLight reads the signals and lowers the lighting to preset levels,” Chen explains.

TARGETING LIGHTING SYSTEMS
Lighting experts at Lawrence Berkeley National Laboratory suggest that lighting controls, which can dim or turn off lights automatically, could actually reduce lighting in commercial buildings by almost one-half. In fact, LBNL researcher Francis Rubinsten goes so far as to predict that if 30% of commercial buildings adopted lighting control systems by 2025, the nation could reduce its energy use by 700 billion kilowatt-hours, saving about $50 billion.

Starting with the occupancy sensor, Craig DiLouie, education director for the Lighting Controls Association, Arlington, Va. (www.aboutlightingcontrols.org), reports that the technology is “a proven, reliable method of automatic lighting control” that can deliver significant energy savings—35% to 45% in offices, according to the New Buildings Institute—while complying with the automatic shutoff requirements of most commercial building energy codes.

Manufacturers are steadily improving their products and now offer systems that offer both reliability and flexible design options. For example, OWP/P’s Kesler lists such technological advances as improved lens technology, wireless sensors with built-in transmitters and receivers, and dual-technology components with a combination of ultrasonic, passive infrared, and microphonic sensors to minimize nuisance operations. Craig DiLouie, of the Lighting Controls Association, points out that the dual-technology sensors are ideal for spaces where occupants move very little, such as office environments or classrooms in which students are taking tests.

Other newer product options, according to DiLouie, include “manual-on” sensor switches, which maximize energy savings by requiring the user to turn the lights on manually while it turns them off automatically. Even more efficient is the bilevel switching sensor, which combines manual-on/auto-off or auto-on to 50%/auto-off.

Do these lighting controls reduce energy usage? A comparative study of eight office spaces, recently conducted by California Lighting Technology Center (www.aboutlightingcontrols.org/education/papers/2009/2009_bilevel_study.shtml), revealed the following energy savings as compared to baseline performance:
• An auto-on to 100% bilevel occupancy sensor: 34% savings.
• An auto-on to 50% bilevel occupancy sensor: 52% savings.
• A manual-on bilevel occupancy sensor: 46% savings.


However, even with all these capabilities and potential savings, the systems must be properly specified in order to work effectively. “Poorly designed systems can actually waste energy by turning on lights needlessly,” says Eich. This can happen when occupants walk down a corridor of unoccupied offices, causing the lights to turn on in each office as they go by.

DiLouie further cautions that, while occupancy sensors are a safe, reliable, proven method of occupant detection and automatic shutoff, they “must be properly applied, installed, and calibrated to be most effective. If misapplied, nuisance switching may result, which could irritate occupants and jeopardize savings.”

System commissioning to ensure proper operation, settings, and adjustments are made at the time of occupancy is also advised, says Kesler. To this end, a newer technology, self-calibrating sensors, can be helpful to automate commissioning, thereby maximizing energy savings.

            
This skylight system at the North Shore Long Island Jewish Health Monter Cancer Center, Lake Success, N.Y., brings natural light into the space. Photo: EWINGCOLE
        

Integrated daylighting and dimming. As desirable as natural light is, many experts actually claim that, in and of itself, it does not save energy and is therefore not inherently sustainable. Rather, a well-designed daylighting control system is essential to properly harvest natural light, says the LCA’s DiLouie.

Moreover, says DiLouie, daylighting control systems are integral to energy standards like the International Energy Conservation Code (IECC) and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards. “The latest generation of energy codes, such as IECC 2009 and Title 24—and likely ASHRAE 90.1-2010 and ASHRAE 189.1—are beginning to require daylighting control, and it is particularly favored in LEED projects where designers attempt to exceed 90.1 for energy points,” he says.

According to Kensky, LEED for Commercial Interiors (LEED-CI) awards a credit for daylight-responsive controls within 15 feet of all windows.

But in terms of tweaking the design, the Bala engineer explains, “The better systems are integrated with photosensor and dimming ballasts that will match a specified light level for the space by dimming the lights. The space can be set up so that the fixtures farther away from the natural light source will dim less and the light levels will be uniform and consistent throughout the space.”

For what he calls the “ultimate in performance,” DiLouie recommends a digital dimming system, which he sees as ideally suited for daylighting control because control zones can be set up and reconfigured over time without hardwiring. However, “If the dimming system is not properly designed and commissioned—for example, if the photosensor is improperly placed—occupants may respond negatively to improper operation and the owner may disable it, negating the benefit of the investment.”

In addition, says Kesler, higher installed costs, more complicated systems to operate and maintain, and contractors who are less familiar with such products can add to the complexity of using such systems in building projects.

To address some of these obstacles, LBNL’s daylighting group is working on an integrated building-equipment communications network, or IBECS. This novel system is intended to better enable building lighting and envelope systems to respond automatically to changes in occupancy, daylight levels, and energy costs. They also give occupants more control over their environment, says LBNL’s Chen.

Essentially, the research team is taking a networking technology called embedded-device networks and integrating it with lighting and envelope controls. The ultimate goal, says Chen, is to achieve lighting-related savings on electricity consumption of 59% in new construction and 43% for retrofits by 2015.

       
An innovative LED fixture at the Cooper University Hospital lobby in Camden, N.J. LEDs have low wattage and use no mercury. Photo: EwingCole
     

Light-emitting diodes. Another pocket of promising research is in the area of light-emitting diodes, or LEDs. Although the technology is generally associated with decorative and specialty applications, it is being considered more and more for general, white-light illumination. “LED lighting is very in vogue and is featured by almost all manufacturers for its energy-saving capabilities,” relates Kensky. “With low wattage, no mercury, and extremely long life, it is touted as the future of lighting.” According to Kahn’s Papademos, other benefits of LEDs include:
• LED point sources can easily be controlled.
• LEDs introduce less heat into the building’s envelope as compared to other lighting sources.
• LEDs offer infinite color combinations, when properly specified and designed.
• The LED’s illuminated surface is not hot to the touch.



On the other hand, LEDs have their own problems, says Peter Levasseur, AIA, LEED AP, director of sustainable design, and Mary Alcaraz, PE, LC, LEED AP, a principal and director of lighting design, with EwingCole, Philadelphia. For example, LEDs generally cost more than other lighting options and sometimes have limited light output.

There is also the unresolved question of what to do with the lamp at the end of its life. Papademos explains that the current philosophy is to design a fixture around the LED, so that when the light source eventually needs to be replaced—perhaps 10 or 15 years down the road—it may follow that the fixture would need to be replaced as well. Papademos also mentions a lack of common definitions and terms among LED manufacturers, and a need for more standardized tests and measurements to back up manufacturer performance claims. “Quite often, if it sounds too good to be true, it is,” he says.

At the same time, researchers are diligently working to bring the technology to a point where it can be competitive with halogen, fluorescent, and metal halide lamps. For example, organic light-emitting diodes (OLEDs) are reported to offer power-conversion efficiencies close to those required for energy-efficient operation, although at this point, only for green and red light, and with insufficient luminances for interior building lighting, according to the Washington, D.C.-based Optoelectronics Industry Development Association (www.oida.org).

A related recent achievement, reports the U.S. Department of Energy, is a white OLED that surpasses the power efficacy of incandescent bulbs through the utilization of a high-efficiency phosphorescent technology. For more, see: http://www1.eere.energy.gov/buildings/ssl/highlights_udc08.html

OTHER WAYS TO SAVE LIGHTING ENERGY

           
Light shelves at the Olympus Headquarters, Center Valley, Pa., help maximize daylighting opportunities. Photo: EwingCole
            

Light-reflecting materials and light shelves. Whether it’s with light shelves or light-reflecting materials such as extruded aluminum or composite aluminum panels, another way to save on electrical lighting costs is by maximizing daylight penetration.

“Light shelves reflect and direct daylight onto the ceiling and deeper into the space and reflective materials can increase daylight penetration by as much as four times the distance from the floor to the top of the windows,” Kesler explains.

Although light shelves do add to first cost, they have become more affordable in recent years, according to Alcaraz and Levasseur. They can also be integrated into wall systems and are available in multiple material types and options.

EwingCole designers point out, however, that their appearance may be somewhat jarring to occupants, occasional maintenance problems may arise, and the exterior shelves might create unwanted sites for bird habitats.

In terms of design, their effective use is very much dependent on such factors as 1) the size of shelf, 2) horizontal or vertical placement, 3) interior versus exterior installation, and 4) building orientation, says Kesler, who warns that “they are not appropriate in tropical or arid climates due to intense solar heat gain.”

Papademos adds that designs should also be careful to allocate sufficient building height for proper design and placement, and aesthetically blend any exterior shelves into the building façade.

Prismatic glazing. Another effective way to improve natural light distribution and illumination is by using prismatic glass, acrylics, and polycarbonates. Offering a higher quality of daylight within a space than clear or typical obscuring material, translucent prismatic materials are being used more and more as the fenestration material in lieu of other more traditional materials.

For example, more than 2,000 pieces of prismatic glass were installed in the base of the high-profile One World Trade Center project. The SOM-designed Freedom Tower utilizes the reflective, refractive, and light transmission properties of the glass to create a dynamic, shimmering façade.

Other typical applications include installing prismatic glass on the top third of a window to refract sunlight toward the ceiling, or in roof lights to keep out radiation while letting in sunlight.

Translucent materials. Another interesting daylight-enhancing choice is the use of translucent materials. In addition to letting in sunlight, many translucent panels and wall/roof assemblies offer higher R-values than conventional windows. While more commonly used for exterior wall construction, the materials can also be fitted with light fixtures to control brightness, Papademos explains.

As for the latest technological advances in this realm, Alcaraz and Levasseur report more affordable glazing, tinting, frit, and, color options. Also, many Building Teams are using 3D modeling and daylighting visualization tools, which enable building owners and end-users to see designs prior to construction.

             
The choice of interior glass glazing reduces solar gain while letting the sun shine in at SCA Americas, Philadelphia. Photo: EwingCole
           

Perhaps one of the most exciting developments is a new translucent panel product on the market that utilizes aerogels, among the world’s lightest solid materials and a material formerly used exclusively for extreme environmental conditions such as the body of the space shuttle.

Claimed to deliver thermal insulating and light transmitting factors two to four times better than comparable products, aerogel-filled translucent panels were recently specified for the new Yale Sculpture Gallery, an AIA/COTE 2008 Top 10 Green Project, designed by KieranTimberlake Associates. Integrated with a triple-glazed curtain wall and exterior sunshading system, the panels are so effective on their own at reducing solar heat gain and cold-weather heat loss that they are successfully balancing the overall performance losses from the glass areas.

SAVING WATER
Although fresh water is very much taken for granted, the fact is that supply is declining. “Some experts are even more concerned with the supply of fresh water than the supply of energy,” says Andrew P. Simpson, LEED AP, a mechanical engineer with R.G. Vanderweil, Boston. He notes that considerable energy is used to pump and treat water, too.

Cost savings is strong motivator. “One of the least costly ways to conserve water—low-flow and no-flow fixtures—has amazing saving potential, reducing water usage by a staggering amount,” says Simpson. “In fact, the payback period for efficient fixtures is typically measured in months, and water savings can amount to hundreds of thousands of gallons a year.”

Not only do low-flow fixtures save a great deal of water, but they are required by the National Plumbing Codes. Consequently, they are quite widely used at this point, says Kensky.

While high-efficiency toilets—which use 1.28 gallons per flush and urinals at just 1/8th gpf—have  succeeded in raising the bar on water savings, vacuum-waste systems are now coming out, making it possible to flush a toilet with less than 0.5 gpf, according to David E. DeBord, CPD, LEED AP, a senior associate with Environmental Systems Design, Chicago.

At the same time, Kesler points out that, in general, some of the “extremely low-flow” fixtures on the market may not perform well and might skew the public and owner perception regarding the efficacy of low-flow fixtures in general.” And the same goes for waterless fixtures, which aren’t even legal is some states, including Illinois and Minnesota.

“We rarely use these because most of our clients and owners are concerned about the extra expense and maintenance required, and the public is still a bit wary of the waterless [products],” relates Donia Bessa, PE, CPD, LEED AP, a mechanical engineer in the healthcare division of TLC Engineering for Architecture. “You also have to be careful what drain piping you use because undiluted urine will eat away metal piping.”

To address this last issue, DeBord suggests providing either a manual flush valve for maintenance staff to periodically operate to wash out the piping, or a valve actuated by a timer. “This would still keep water usage at a minimum, yet provide some protection for the piping systems.”

Dual-flush systems. These low-flow systems made their debut on the U.S. market only in recent years, even though they have been pretty much standard in Europe, Israel, and Australia for years. These units save water by using a lower flush rate for liquid waste disposal and a higher flow rate for solid waste disposal. Easy to retrofit, an existing flush valve can be replaced with a dual-flush handle.

The catch is that the toilet’s effectiveness is dependent on the user. Consequently, occupants must be instructed how to flush the units—and the learning curve isn’t always so smooth. “Our feedback from owners indicates that it’s difficult to change people’s habits,” confirms Bessa. In fact, TLC has actually found it easier to specify the 1.28-gpf toilets, both for this reason and to earn points more easily using the LEED template.

One way around this challenge is to install a time sensor, which automatically selects the flush mode depending on the amount of time the toilet is in use.

Hands-free systems. Hands-free fixtures are almost commonplace for public buildings, as well as commercial and institutional facilities. In addition to flush valves and faucets, end-users are now also opting for touchless soap dispensers and hand dryers. Not only are they hygienic and able to save significant volumes of water, according to Dunham’s Holland, but some of the newer fixtures also have temperature adjustments, the lack of which was, in the past, a drawback for many clients.

Another improvement making these products more attractive is longer-lasting batteries. “The newer models incorporate tiny water-powered turbines that trickle charge the batteries, vastly increasing their life span and reducing maintenance,” explains Bessa. A/C-powered sensors are another choice, requiring even less maintenance, although they won’t function during power outages unless put on emergency power. They also require periodic adjustment of the sensor angles and distances to ensure optimal operation, according to Kesler.


About the authors

C.C. Sullivan is a communications consultant and author specializing in architecture and construction. Barbara Horwitz-Bennett is a writer and contributor to construction industry publications.



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Reed Business Information is a Registered Provider with the American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available on request.
       This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.


         
 

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