Existing laboratories, whether built decades ago with now-outdated equipment or more recently with state-ofthe- art technology, provide significant opportunities to reduce energy consumption, improve sustainability, and manage costs. Typical laboratory facilities are extremely energy intensive. Research by theU.S. Department of Energy suggests that energy consumption per square foot in laboratories is on average five to ten times higher than the energy consumption in standard commercial office buildings. Certain specialty laboratories can consume as much as 100 times the energy of similarly sized commercial facilities. Fortunately, laboratories have the potential for dramatic energy savings, which can be realized through cost-effective energy retrofits at no upfront cost to the laboratory owner.
While laboratories offer distinct challenges specific to their unique health and safety requirements, the basic process and principles that are used to improve energy consumption patterns across standard building types are the same. The energy retrofit process begins with an energy audit in which all aspects of a buildings energy usage are examined in order to identify opportunities for savings. The energy audit focuses on the equipment and systems that contribute most heavily to the buildings energy profile. For a laboratory, significant energy consumption can be traced to mechanical systems, lighting systems, and plug-load equipment.
Energy performance contracting (EPC) allows facilities to complete energy and water efficiency projects without incurring upfront capital costs.
Cooling, heating, and ventilation systems are generally the largest consumers of energy within a laboratory, in part because laboratory air-quality requirements greatly exceed the requirements of commercial buildings. While the standard office building is designed for one or fewer air changes per hour (ACH)meaning that fresh outside air is cycled through the building once every hour or less frequentlylaboratories are often designed for ventilation rates between 6 and 20 ACH. These air exchanges typically occur 24 hours per day, seven days per week, regardless of laboratory usage.
Overventilation occurs when more air exchanges occur per hour than are needed. This results in wasted energy from fans moving large volumes of air into and out of the laboratory and from systems used to heat or cool the makeup outside air. While an exchange rate of 10 or 20 ACH (or even higher) may be necessary when air becomes locally contaminated, the exchange rate for many laboratories was arbitrarily selected by designers years ago based upon rules of thumb. In addition, the ventilation rate in many laboratories remains constant regardless of whether any workstations are in use. Compounding this problem is the fact that the energy consumed by a motor or drive is a function of the cube of its speed. In other words, if a fan is turning twice as fast as it needs to, it is theoretically using eight times (23) as much energy as necessary.
Thus, correcting overventilation is one of the most common opportunities for mechanical energy savings in a laboratory. There are a number of ways to implement improvements:
- Reexamine the ventilation rates that are actually required for the laboratorys current activities. If a space is being overventilated, it may be cost-effective to downsize mechanical equipment (air handlers, chillers, boilers, water pumps, etc.), provided minimum airchange code requirements continue to be met.
- Swap out constant-volume air handlers and fixed-speed drives for variable air volume (VAV) and variable frequency drive (VFD) equipment that can adjust motor speed based on load conditions. This opportunity is especially common in older laboratories that were designed before modern control technology was developed.
- Install highly accurate sensing and control systems that can precisely measure air quality so that ventilation rates increase when contaminants are present and decrease when less ventilation is required. These sensors are particularly useful for controlling ventilation through fume hoods at workstations.
A surprising amount of energy in a laboratory is consumed by lighting. In many instances, entire rooms in laboratories are lit by ceiling-mounted fixtures that are controlled by a single switch. Due to the variability of researchers work schedules, it is not uncommon for the lights in a laboratory to remain on constantly. In addition, overhead lighting systems are often designed imprecisely to provide high levels of light to entire rooms. As a result, much of the light from these fixtures is wasted on space that does not require high levels of lighting. Compounding the problem is the fact that lights release heat. Heat gain from lighting and other electrical equipment increases the amount of energy required to cool building spaces.
Fortunately, inefficient lighting systems are easily addressable with a variety of solutions:
- Implement task lighting that is controlled by individual users and provides more efficient, focused light at workstations so that overhead light levels can be reduced.
- Selectively remove the lamps from some percentage of the total light fixtures in a space, or reduce the wattage on existing light fixtures. For example, 25-watt T-8 fluorescent tube lights provide almost as much light output as 32-watt T-8s but use 22 percent less electricity.
- Install lighting controls that monitor occupancy and automatically adjust light levels accordingly. Occupancy controls have advanced considerably from the days of old when people occasionally needed to stop working and wave wildly to get the lights back on, and the addition of dimming controls has greatly increased savings opportunities.
- Utilize natural daylight, when possible, by installing skylights where practical and by adding lighting controls that can leverage natural light from perimeter windows by reducing output when natural light is present.
The plug load (or total electricity consumed by the various pieces of equipment that are plugged into electrical outlets) within a laboratory is another major contributor to a laboratorys energy consumption. Some inefficiency results from a lack of consideration for energy performance when purchasing laboratory equipment. In addition, many devices consume electricity regardless of whether they are in use. This ghost load occurs around the clock and adds to wasted energy.
Laboratories can take the following actions to reduce plug-load inefficiencies:
- Consider total cost of ownership (TCO) when making equipment purchases. While high-efficiency systems may come with higher price tags, the future benefits of these systems often justify the upfront cost premium.
- Look for equipment with the ENERGY STAR label. Though it is not available for all types of equipment, this label means that the equipment has met or exceeded a rigorous series of product quality and efficiency standards.
- Use vacancy sensor plug strips for equipment that does not require power when not in use. Vacancy sensor plug strips address ghost loads by fully shutting down power to pieces of equipment that would otherwise draw power unnecessarily.
- Implement power management for IT equipment. Computers and monitors can draw considerable amounts of power even when they are in a suspended state. However, operating system settings or software applications can be configured to fully power down computers when they are not in use.
Other opportunities for energy savings
Though common solutions such as those described above can yield considerable energy savings, it is still important to closely examine how a laboratory is being used and how its systems interact. For example, in a recent laboratory energy audit, we found a 2,000-square-foot specialty room with a large, constant cooling load that is causing the central HVAC system for a 96,000-square-foot building to run constantly, often at less-than-ideal efficiencies. During normal work hours, the chiller runs efficiently at nearly full capacity to cool the entire building, as designed. On nights and weekends, the chiller continues to run but at much less efficient, lower capacity because it is only used to cool the specialty room. To solve this, we plan to add a dedicated cooling system for the specialty room to allow the main building HVAC system to shut down during off-hours. Each system will therefore run more efficiently for its given load.
It is not uncommon for laboratories with highly efficient equipment and sophisticated control systems to still use significantly more energy than expected. This can occur because control systems and equipment settings may have been gradually changed over time so that they no longer function optimally. A solution to this problem is whole-building retro-commissioninga systematic process to identify inefficient conditions and adjust control systems to ensure that equipment performs efficiently for its current usage. This measure is inexpensive to implement and can also be completed quickly for immediate improvement.
Beyond energy-efficiency opportunities, laboratories, particularly those with large energy loads, should also be evaluated for renewable energy potential. On-site distributed generation systems, such as rooftop solar or small-scale wind, can be implemented to provide clean, renewable energy to laboratories. Unfortunately, distributed generation does not always make economic sense as an independent solution. However, energy savings from other energy-efficiency measures can be bundled with the cost of the renewable energy systems to overcome this hurdle so that the overall project reduces the laboratorys energy-related spending. For instance, we were able to identify a number of fast-payback energy conservation measures on a recent project for a federal laboratory to provide a cost-effective 1 MW distributed rooftop solar photovoltaic system for our client.
Paying for energy upgrades
Many laboratory managers are undoubtedly interested in pursuing energy-efficiency projects to help manage costs yet lack the budget to do so. Fortunately there are a number of financing mechanisms available that do not require up-front capital expenditures. Two financing vehicles that are typically used for energy projects are energy performance contracts (EPCs) and energy services agreements (ESAs). Under a performance contract structure, an energy service company (ESCO) conducts preliminary energy audits, identifies energy conservation measures, arranges project financing (generally from the capital markets), and implements the energy project. The ESCO can even take responsibility for the long-term operations and maintenance of the newly installed project components. Project financing is amortized over the term of the contract, with a percentage of the projects energy savings covering the debt service. Once the debt is fully amortized, all the energy savings that the project accrues are kept by the facility in which the measures were implemented.
An energy services agreement is generally used for renewable energy projects, though it can also be set up for energy-efficiency measures. ESAs are structured so that the facility pays a set price for either energy delivered or energy saved over the course of a defined term. Energy production (or energy reduction) is measured and verified throughout the term of the contract so that the facility only pays for the exact benefits that it receives. An ESA allows a laboratory to lock in power prices over a long period of time, providing a better sense of future budget commitments.
Though they have been ignored for years by the energy-efficiency industry, laboratories now represent one of the largest areas of opportunity for organizations that want to improve sustainability, reduce their carbon footprint, and decrease energy spending. Because a typical laboratory has so many cost-effective energy conservation opportunities, energy retrofits can often be paid for entirely by using the energy savings they will generate. As a result, the greatest cost of a laboratory energy retrofit has become the cost of delay.
Clark Energy Group (www.clarkenergygroup.com) is a DOE-qualified energy services company with a focus on energy-efficiency retrofits and renewable energy development.