Existing laboratories provide significant opportunities to reduce utility consumption, improve sustainability, and manage costs. Laboratory facilities are energy intensive. Research by the U.S. Department of Energy suggests that energy consumption per square foot in laboratories is on average five to ten times higher than in standard commercial office buildings. Certain specialty laboratories can consume 100 times the energy of similarly sized commercial facilities. Fortunately, laboratories offer the potential for dramatic utility savings through cost-effective retrofits.
Converting utility data into actionable insight
While laboratories offer distinct challenges specific to their unique health and safety requirements, energy industry best practices that are rooted in data and analytics still apply. Building or sustainability managers, engineers, and energy service companies (ESCOs) can now efficiently gather millions of data points related to the operation of all major energy systems in a typical facility. This data can be collected from a variety of sources: the facility’s energy management and control system, portable data loggers and sensors that can be placed on key systems, the local utility (which can provide detailed information on historical energy consumption from each meter), and public data sources (e.g., weather data).
This data can then be converted into actionable insights using customized software applications that allow energy management practitioners to efficiently (1) standardize data from different sources, (2) identify and visualize relationships among factors, (3) normalize dependencies, and (4) predict the impact of changes to the energy systems. By focusing first on the building systems with the highest utility consumption, it is possible to quickly identify the biggest opportunities for impact.
For a laboratory, significant utility consumption can be traced to mechanical, lighting, computing, and water systems.
Energy loads from heating, ventilation, and cooling are generally the largest consumers of energy within a laboratory in part because laboratory air quality requirements greatly exceed those of commercial buildings. While a 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—laboratories are often designed for ventilation rates between six and twenty ACH. These air exchanges typically occur 24 hours a day, seven days a week, regardless of laboratory usage.
Over-ventilation occurs when there are more air exchanges per hour than are needed. This results in wasted energy because fans must turn faster to move more air into and out of the laboratory, and the energy consumed by a motor 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. Further, energy needs to be used to heat or cool all of the excess outside makeup air.
While an exchange rate of 10 or 20 (or even higher) ACH may be necessary when air becomes locally contaminated, many laboratories operate as though they are constantly experiencing worst case conditions. However, technologies now exist to automatically adjust ventilation based upon actual laboratory conditions at any given time. Thus, correcting over-ventilation can generate significant mechanical energy savings in laboratories. There are a number of ways to implement improvements.
- Reexamine the ventilation rates that are required for the laboratory’s current activities and equipment. If a space is being over-ventilated, it may be cost effective to reduce the ventilation rate and, potentially, downsize mechanical equipment (e.g., air handlers, chillers, boilers, water pumps), provided that current code requirements are met.
- Convert constant volume air handlers to variable air volume and replace fixed-speed drives with variable frequency drive (VFD) equipment that dynamically adjusts motor speed based on load conditions. This opportunity is especially common in older laboratories that were designed before modern control technology was developed.
- Install sensing and control systems that can precisely measure air quality (especially through fume hoods) so that ventilation rates increase when contaminants are present and decrease when less ventilation is required.
- Install automatically closing sashes with controls for fume hoods. Most fume hoods run constantly at full speed, even when laboratories are unoccupied. Automatically closing sashes with controls can reduce wasted energy by adjusting ventilation based on sash position and by minimizing ventilation when fume hoods are not in use.
Because of recent advances in lighting technology, it is now often cost effective to replace light fixtures with new technologies that are more efficient, last longer, and produce better quality light. Inefficient lighting systems are easily addressable with a variety of solutions.
- Replace existing fixtures with high-efficiency light-emitting diode (LED) fixtures. LEDs offer improved color rendering, reduced energy consumption, and longer useful life. Together, these benefits improve workplace satisfaction and safety while reducing operating expenses and maintenance-related interruptions.
- Install advanced lighting controls that can adjust the light output of each fixture based upon occupancy, measured light levels (i.e., daylighting), and local user overrides.
- Implement task lighting that is controlled by individual users to provide focused, task-specific light at workstations so that overhead light levels can be reduced.
In small data closets and large data centers alike, computing equipment consumes energy directly and indirectly through cooling systems, uninterruptible power supplies, etc. Often, smaller computing facilities can be consolidated into larger focused data centers. This reduces the need for 24x7 cooling in buildings that previously housed small data centers. It can also reduce computing loads directly if coupled with server upgrades and/or virtualization.
Beyond data center consolidation, there are a number of ways to reduce energy consumption in existing computing facilities:
- Adjust cooling set points to current standards from the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). The days of the frigid data center are gone. ASHRAE recommends operating data centers at temperatures as high as 81°F. Modern servers and computer hardware are designed to operate at these temperatures.
- Implement air-side or water-side free cooling. Air-side economization uses outside air to cool the data center whenever the outside air temperature and humidity are below the data center set points. In many climate zones, it is possible to maintain appropriate space temperatures in data centers for more than 7,000 hours per year using only outside air. This means that mechanical cooling would be required for less than 1,800 hours per year.
- Upgrade existing computer room air conditioner (CRAC) units with VFDs or electronically commutated motors and by adding central control for all CRACs. It is not uncommon for some of the CRACs in a data center to be running at full speed attempting to cool the data center while other CRACs are trying to heat the data center. By centrally controlling the CRACs and allowing them to adjust their speed based on load, this fighting between CRACs can be prevented— eliminating wasted energy in the process.
- Improve rack configurations and air distribution. Data centers can be cooled much more efficiently when the server racks are arranged to create separate hot aisles and cold aisles—with a physical air barrier separating the cold air needed at the front of the servers from the warm exhaust air coming out of the back of the servers.
Laboratory water systems are typically composed of domestic and process uses. Domestic water systems generally offer strong paybacks and are largely consistent across facility types. Typical upgrades include low-flow toilets, urinals, faucet aerators, and showerheads. Process water measures are highly customized but can also generate significant savings. For example, a recent CEG Solutions (Arlington, VA) project at a microelectronics laboratory included reverse-osmosis water filtration system retrofits. High-efficiency variable flow controls and a wastewater recovery system were installed. These measures reduced the load on the filtration system, thereby increasing the filter life and allowing for wastewater reuse in a local cooling tower. Generalizable lessons from this example include the following: First, look for ways to reuse wastewater from water-intensive processes. Cooling towers and irrigation systems are good candidates for reuse because they consume a lot of water. Second, look for ways to employ variable speed or variable flow controls for processes that have inconsistent loads or usage.
Paying for energy upgrades
Many laboratory managers are interested in pursuing energy efficiency projects to help manage costs, yet lack the budgets to do so. Fortunately, there are a number of financing mechanisms available that do not require upfront capital expenditures, including energy savings performance contracts (ESPCs), power purchase agreements (PPAs), and property-assessed clean energy (PACE).
- Under an ESPC, an ESCO conducts energy audits, identifies energy conservation measures, arranges financing, and implements the energy project. Savings are then measured and verified using clearly defined protocols. The ESCO can even take responsibility for long-term operations and maintenance of the newly installed project components. Project financing is amortized over the term of the contract, and the financing payments are paid for using the ongoing operational savings that result from the project. Once the debt is fully amortized, all the ongoing savings accrue to the client facility.
- PACE financing works similar to ESPC financing and can be used for energy-related facility upgrades in localities that have approved PACE programs. (PACE is locality-dependent; so check first to see if your locality has a PACE program.) After the work is completed, the locality adds a special assessment to a facility’s property taxes that is used to repay the financing with a small interest charge.
- PPAs are used for renewable energy projects, though they can be adapted for energy efficiency measures. PPAs are structured so that the facility pays a set price for energy delivered over the course of a defined term. Energy production is measured throughout the term of the contract so that the facility pays only for the exact benefits that it receives.
Laboratories represent a large area of opportunity for organizations that want to improve sustainability, reduce their carbon footprint, and decrease operational expense. Because a typical laboratory has so many cost-effective energy conservation opportunities, energy retrofits can often be paid for entirely from the cost savings they will generate. As a result, the greatest cost of a laboratory energy retrofit has become the cost of delay.
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