The Greener Lab
- By Lisa Reindorf
- April 1st, 2011
Many university campuses have older science buildings with outdated laboratories. Teaching and research facilities have evolved greatly since the time these buildings were constructed. Scientists now require modernized laboratories that enable team research and facilitate collaboration. But antiquated facilities fall short in another way. Conventional laboratory buildings consume up to ten times the energy of typical buildings due to their specialized HVAC requirements, and older lab buildings were particularly energy inefficient. How does a university upgrade these laboratories to current standards, particularly in regard to energy conservation?
Then and Now
First, it is helpful to understand some of the key differences between these older laboratories and ones built to current standards. For one, older laboratory buildings were designed with fixed rooms and systems, and therefore lack flexibility. Compared to today’s requirements, there is a limited service capacity. Research and teaching labs now call for flexibility in layout and furnishings, as well as collaborative spaces, daylight, and new technology. Current mechanical systems are vastly more energy efficient than those in older labs.
Laboratories and other science facilities are among the most energy consuming of building types. That is because air that is heated or cooled cannot be recycled, due to the potentially hazardous nature of some of the materials used. The typical older research laboratory using chemicals or biological materials is designed to provide generally between 10 to 20 air changes per hour. Greening these labs requires balancing safety with reduced energy usage. The most effective strategies incorporate reduction of unnecessarily high air change rates, air flow reduction for hoods, updating mechanical systems with better controls, and heat recovery for the supply and exhaust air systems.
Air hoods protect the safety of lab workers while they work with chemicals and/or biological materials. Reconditioning this air can add thousands of dollars per hood to an institution's yearly energy bill. (It appears that “hood sash management” & “replacing outdated fume hoods” are two separate concepts, so I’ve edited here with that assumption) The most effective air reduction method involves replacing outdated fume hoods with either low-flow hoods or variable air volume (VAV) hood controls. Energy savings can also be realized through the installation of fume hood sash restrictors, as well as occupancy and proximity sensors. Existing auxiliary fume hoods can also be retrofitted with controls that limit the airflows while still protecting the hood workers.
Heat and Energy Recovery
Heating and cooling the extensive amount of air utilized “required for the required ”frequent air changes consumes enormous amounts of energy. Installing energy recovery systems can substantially reduce the use, and therefore the cost, of energy in laboratories. These systems recycle thermal energy from exhaust air by recovering heat and cooling from the hood and general exhaust. This energy is then transferred back into the air intake system for redistribution into the building.
There are many types of heat recovery systems that can be utilized in building retrofits.
Popular ones include rotary enthalpy wheel, fixed plate, heat pipe, and run-around loop. Choosing the appropriate system depends on a variety of factors, including the existing building mechanical system and location of fresh air intake and exhaust, as well as the climate. With the right application, these systems can be very cost effective.
Obviously, replacing an entire HVAC system for a laboratory facility is a considerable investment, and in return, building owners and managers want significant energy and cost savings . After installing a new, highly efficient HVAC system, it’s feasible to realize paybacks on energy measures in five to seven years. If the existing systems are already in need of repair or replacement, paybacks can come evenoccur even sooner. For instance, retrofits to fume hoods to reduce airflow can cost up to several thousand dollars per hood. But this is approximately 80 to 90 per cent less costly15 to 20 percent of the cost of than buying new, energy-efficient fume hoods, s. So significant paybacks can occur in only a few years.
If replacing an existing mechanical system in a laboratory facility is not feasible then retro-commissioning the mechanical system is an option. As a laboratory building ages, the mechanical systems degrade in operation. During retro-commissioning the facility is comprehensively tested, adjusted, and calibrated so that HVAC and plumbing systems are functioning as efficiently as possible. Studies have shown that the average measured utility savings are about 20 percent, with simple paybacks often occurring in less than two years.
Upgrading the building envelope (exterior walls, windows, and roof) is also quite effective in reducing energy consumption. Better exterior insulation reduces the flow of heat into the building in the summer and out of it in the winter. Replacing older windows with new, energy-efficient units decreases heat transference as well. Electric consumption can be reduced by “smart lighting” systems that incorporate daylight-responsive and occupancy sensors. Payback in energy savings with these new lighting controls can be realized in as quickly as one year after installation, especially when reinforced by utility incentives.
Let in the Light and Think Green
Reconfiguring laboratories to adapt to a more open model can provide opportunities for yet more energy savings. Updating these laboratories to bring in daylight — and thus reduce the need for artificial light — can be challenging,. B but there are design methods to achieve this goal. For major renovations, laboratories should be located along the building exterior to provide natural light and views. For interior or enclosed laboratories, existing walls can be retrofitted with glass openings to bring in natural light.
A more open laboratory model also allows for flexible and adaptive system types. This, in turn, will enable improved energy performance and prevent costly changes. Lab furniture systems with mobile components should accommodate changes in services throughout the life cycle of the laboratory. New systems have flexible connections for the many types of services: gas, water, electricity, supply and exhaust air, data and electronic systems. The utilities plug into the benches from the ceiling and unplug if benches move to another area.
When renovating, green your laboratory with materials that both contain recycled content and can be recycled when they are no longer needed. Sustainable materials could include FSC-certified wood doors and casework, carpet with recycled content, concrete with reclaimed fly ash, rubber tiles, and epoxy counters. Also, to maintain high indoor air quality, materials with low pollutant emissions should be specified.
In conclusion, while renovating laboratories to adapt to current teaching and research practices, providing more open laboratories with improved daylight, flexible systems, and durable green materials will help reduce energy consumption. However, upgrading mechanical systems, installing heat recovery systems, and improving the building envelope are the most cost effective and efficient means of energy conservation in older academic laboratories.
Lisa Reindorf, AIA, LEED-AP, is a principal for Goldman Reindorf Architects in Newton, MA. She can be reached at 617/467-3119.