Laboratories in the U.S. are energy-intensive facilities that use anywhere from 30 to 100 kilowatt-hours (kWh) of electricity and 75,000 to 800,000 Btu of natural gas per square foot annually. Actual use varies with such factors as the age of the facility, the type of research done there, and the climate zone in which the lab is located. In a typical laboratory, lighting and space heating account for approximately 74 percent of total energy use (Figure 1), making these systems the best targets for energy savings. Because laboratories consume so much energy, the potential for energy and dollar savings through energy-efficiency improvements and energy conservation is impressive—some studies estimate that implementing such measures can result in savings as high as 50 percent for laboratories and cleanroom facilities.
Although detailed benchmarking data on energy usage in laboratory facilities have historically been hard to come by, researchers working with the Laboratories for the 21st Century (Labs21) program, which is sponsored by the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Energy, are currently collecting data measured by others on lab facilities in a variety of climate zones. You can use these data to benchmark your facility against others like it—always an effective first step toward reducing energy use.
Benchmarking is particularly important because of the wide variation in laboratory energy use. It shows you how your facility is using energy, can help you indentify the most cost-effective areas for improvement, and provides a baseline against which improvements can be measured.
Programs like Labs21 help laboratory owners and managers to benchmark, monitor, and report annually on building energy performance. More comprehensive tools are available from rating programs like the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) for Labs program or the Labs21 Environmental Performance Criteria. These programs can assist you in benchmarking your facility, identifying areas for improvement, and ultimately getting recognition for your efforts.
Many laboratories can benefit from simple low- or nocost energy-expenditure reductions, such as turning things off and turning things down.
Turning things off
Turning things off seems simple, but remember that for every 1,000 kWh that you save by turning things off, you save $100 on your utility bill (assuming an average electricity cost of 10 cents per kWh).
Lighting. Turn lights off when they are not in use. When properly installed, occupancy sensors and timers can help to achieve this. A no-cost option is to simply train staff to turn off lights as part of their closing procedures (you can also help by identifying the location of light switches on a posted notice).
Computers and monitors. You can gain significant energy savings by verifying that power management settings are enabled on individual computers and monitors, forcing them to enter sleep mode after a specified period of inactivity. Most desktop computers built since 2008 are shipped with these settings enabled. Power management settings can cut a computer’s electricity use roughly in half, saving from $25 to $75 annually per computer. If you need help activating power management features on individual computers, the EPA offers detailed instructions by operating system on its ENERGY STAR® website (just search on “computer power management” plus your operating system). Some users may be concerned that automatic software updates will be inhibited if power management settings are enabled, but that is not the case. Updates will automatically begin to download when the computer awakens from sleep mode.
Other plug loads. Plug loads in laboratories are typically higher than in other buildings. Though office-building plug loads fall into the 0.5 to 1.0 watt per square foot (W/ft2) range, laboratory plug loads can range from 2.0 to 20.0 W/ft2. With so much equipment in place, turning it off when it’s not in use can represent a big savings opportunity. To automate this process, consider buying and installing smart power strips that can turn off equipment when an area is vacant or when the equipment has been idle for a set period of time. Additionally, when it’s time to replace equipment, look into purchasing ENERGY STAR®–rated or other energyefficient products.
Turning things down
Some equipment cannot be turned off entirely, but turning it down to minimum levels where possible can save energy.
Reduce light levels. Ensuring that light levels are sufficient for the tasks at hand—not unnecessarily bright—can help reduce energy costs. In spaces where natural lighting is available, lights can be dimmed, or selected lights can be switched off in response to the availability of sunlight.
Implement HVAC setbacks. Adjusting overall temperature settings by just a few degrees can yield significant energy savings without affecting occupant comfort levels. When possible, make sure that HVAC settings in stockrooms, offices, and other peripheral rooms are at minimum settings.
Although the actions covered in this section require more-extensive implementation efforts and have higher costs, they can dramatically increase the energy efficiency of your laboratory while maintaining or improving productivity. Ask your local utility representative for more information about funding or guidance that might be available for such projects.
Because lighting accounts for roughly 21 percent of overall energy use, it’s a great area in which to implement energy-efficiency measures.
Upgrade fluorescent lamps. If your facility uses T12 fluorescent lamps, relamping with modern T8 lamps and electronic ballasts can reduce your lighting energy consumption by 35 percent or more. Adding specular reflectors and new lenses can increase these savings and yield short simple payback periods.
Use CFLs and CCFLs. If you are still using incandescent lamps, replace them with compact fluorescent lamps (CFLs). CFLs use one-quarter of the energy incandescents do, and they last up to 10 times as long. In areas where lamps are dimmed or frequently cycled on and off, consider cold-cathode fluorescent lamps (CCFLs), which, though more expensive, last even longer than CFLs, are easier to dim, and their life is not shortened by frequent cycling.
Install occupancy sensors. Areas that are not consistently occupied—such as storage rooms, restrooms, and back offices— are ideal places for occupancy sensors. They can save 30 to 75 percent in lighting-energy consumption, and they typically yield simple payback periods of one to three years.
Use task lighting. Task lights can improve lighting quality and yield energy savings because lighting an entire workplace at full brightness is inherently less efficient than lighting just the area you need. If you decide to pursue this strategy, make sure that room lights can easily be dimmed or selectively switched using either manual or automated controls. In some cases, task lighting can accompany a delamping project, but make sure that delamping doesn’t create an undesirable light distribution.
Employ daylighting. Using daylight for lighting can reduce both lighting and cooling loads. Although daylighting is an approach that’s generally best implemented in new construction, some daylighting technologies (including light scoops and tubular skylights) can be retrofitted in existing buildings to bring in more daylight without increasing cooling loads or glare. To save energy with daylighting, turn down existing electric lights in response to daylight levels. In addition, studies show that daylighting improves productivity among a building’s occupants—and even small productivity gains can dwarf dollar savings from energy efficiency and conservation alone.
To maintain health and safety and to meet building codes, laboratories require a large volume of ventilation air. Rather than recirculating indoor air, most laboratories use 100 percent outside air to prevent cross-contamination and accommodate the exhaust requirements of the fume hoods that are commonly used. However, relying entirely on outdoor air also presents a significant challenge: all that air must be conditioned, at considerable expense. As a result, heating, cooling, and moving ventilation air in a lab typically accounts for 60 to 70 percent of total building energy use.
Zone systems and spaces. Zoning a laboratory building’s energy systems can prevent energy waste. It is critical to distinguish between lab spaces and non-lab spaces because they have significantly different operational characteristics, energy-using equipment, and energy-use patterns. Laboratory spaces can be energy-intensive, but offices, common areas, and other spaces have far less onerous energy requirements. Designing mechanical systems to accommodate these varied uses saves money and energy.
Design for part-load and variable conditions. Configure fans, pumps, chillers, boilers, and other equipment for highefficiency operation even at very low loads. One way to do this is to use a modular design, using a number of smaller modules rather than one or two large ones and installing controls to ensure that only the components needed to meet the current load run at any given time. Another is to install variable-air-volume air-moving equipment and variablefrequency drives (VFDs) on fans and pumps.
Right-size equipment. Laboratory facilities have highly variable HVAC demands, and engineers often oversize mechanical heating and cooling equipment in an effort to anticipate the convergence of worst-case equipment and climate loads. Their mistaken belief is that this practice provides flexibility and reliability, improves comfort, and reduces the likelihood of litigation; in reality, oversizing is far more likely to waste energy, hurt life-cycle economics, and diminish comfort. By utilizing sophisticated building simulation software and incorporating measured usage data from the Labs21 program, designers can better plan the lab’s HVAC system to maximize system performance and minimize energy consumption.
Improve fume-hood efficiency. Although vital for the safety of employees, fume hoods, which limit exposure to hazardous or noxious fumes by venting them outside, are typically among the largest single sources of energy consumption in labs. Lowering the maximum height of the sash—an adjustable screen that protects the user from chemicals—can result in less fan power needed to maintain proper airflow. As a result, using fume hoods with two-position variable-sash airflow equipment can be an effective way to save energy. Where applicable, consider adding occupancy sensors and VFDs as well. All of these measures can yield large energy savings with attractive returns on investment.
Seal ductwork. Because so much of a lab’s energy use goes toward HVAC, any leaks in the ductwork can result in significant energy waste (not to mention the potential for crosscontamination of air and the dangers involved in fume-hood exhaust reentering the building). One particularly effective approach is to use an aerosol duct-sealing process created by Lawrence Berkeley National Laboratory (LBNL), which is now sold under the trade name Aeroseal. The basic idea of this process is to blow sticky particles into ducts, where they attach themselves to the edges of leaks and effectively seal them. Aerosol duct sealing is currently the only way to seal leaks in ducts made inaccessible by walls and insulation.
Many laboratory facilities have cleanrooms, which have much higher energy intensities than the rest of the lab. In California, for example, cleanrooms account for only 12 percent of the floor space of labs, but consume 54 percent of the total electricity used in these facilities. Because these areas have unique requirements and involve complex systems, the best way for laboratory owners and managers to learn more about potential efficiency improvements is to look through resources like LBNL’s cleanrooms Web page (part of its High-Performance Buildings for High-Tech Industries web site). In particular, LBNL offers a number of best-practice guidelines for HVAC air and water systems, power systems, and process systems, as well as cross-cutting issues like motor efficiency, steam, lighting, commissioning, heat recovery, and right-sizing, all of which may be helpful in identifying areas for improvement.
Because laboratories have many interdependent systems, a comprehensive approach to energy efficiency can result in large net savings and better overall performance.
Design. In new laboratory facilities, a whole-building approach to design can yield significant energy savings while reducing up-front construction costs through rightsized equipment. This approach necessitates a design and construction team that is able and willing to integrate a range of performance criteria at each stage of the process, including first costs, life-cycle costs, quality-of-life issues, flexibility, productivity, energy efficiency, aesthetics, and environmental impacts. A good way to introduce stakeholders to these concepts is to invite them to a design charette at the beginning of the process. This focused, collaborative, interactive brainstorming meeting allows all the participants to address the project’s challenges and opportunities from a crossdisciplinary perspective.
Commissioning. Commissioning is a process in which engineers check and tune up building systems to ensure that they are operating appropriately and efficiently, and it extends beyond the “testing and balancing” that is typically implemented in labs. A 2009 LBNL study indicates that commissioning existing buildings is among the most cost-effective ways to reduce energy use, particularly in high-tech facilities like laboratories. In many labs, whole-building energy savings as high as 30 percent are possible with simple payback periods of less than three years.
In addition to providing energy savings, commissioning often increases system performance and occupant comfort and decreases annual maintenance needs, yielding additional (and significant) non-energy benefits. If your building was previously commissioned, consider investing in recommissioning every three to five years, or in ongoing (also referred to as monitoring-based) commissioning. The latter option involves the installation of a system of sensors designed to continually monitor energy use and system efficiency to ensure maximum persistence of savings, and it may be worthwhile despite potentially high initial costs.
Used with permission, ©2013 E Source
Like this article? Click here to subscribe to free newsletters from Lab Manager