Energy Efficiency Strategies for Laboratories
Otto Van Geet,
National Renewable Energy Laboratory
The energy intensity of laboratories creates great opportunities
to implement energy efficiency strategies and realize short paybacks.
To identify and demonstrate these opportunities, we developed a
simplified model of a laboratory and simulated its energy performance
in Minneapolis, Denver, Seattle and Atlanta. Outside air requirements
and plug loads drive the sizing of the mechanical systems and energy
use in laboratories, so the efficiency strategies we evaluated
focus primarily on ventilation, energy recovery, and process equipment
load (i.e. plug load) impacts.
The laboratory is a four-story, 100,000 square foot building with
70% of the area devoted to laboratories. A constant volume reheat
system serves the building with a maximum relative humidity of
60% and a minimum relative humidity of 30%. Outside air ventilation
is supplied at a constant 2 cfm/sf by high efficiency fans. The
building has a central plant with water-cooled chillers and hot
water boilers. The baseline building meets the ASHRAE 90.1-99 building
energy standard, and measured and predicted energy use data from
laboratory case studies was used to tune the simulation models.
The efficiency strategies are compared to this baseline.
Electricity rates of $0.03/kWh, $7/kW on-peak and $4 off-peak
were used in all four climates. On-peak hours are 8 a.m. to 10
p.m., Monday through Friday. Gas rates are $0.6/therm. A rule of
thumb for office buildings is that energy costs average $1/sf/yr.
For laboratories, the cost is $5-to-$10/sf/yr. The simulation models
reflect this, with electricity costs averaging $4/sf/yr and gas
costs ranging from $2/sf/yr in Seattle to $5/sf/yr in Minneapolis.
Preliminary results show annual cost savings of $2/sf with a variable
air volume system. The fan electricity use alone is reduced by
14 kWh/sf and the peak demand is reduced by 2 W/sf. The paper will
discuss the impact of other measures, such as enthalpy wheels,
heat pipes, run-around loops, evaporative cooling, and plug load
assumptions, as well. Where possible, we will provide rules of
thumb for applying these results to new projects.
Susan Reilly received her Bachelor of
Science in mechanical engineering from the University of Colorado,
and her Master of Science in mechanical engineering from the University
of California in Berkeley. Ms. Reilly is a registered Professional
Engineer in Colorado and California, and has 18 years of experience
in the building energy field. She worked for Pacific Gas & Electric
performing energy audits of commercial facilities, and Lawrence
Berkeley National Laboratory and the Fraunhofer Institute for Solar
Energy Systems researching the energy performance of windows.
Susan Reilly, P.E. is currently president of Enermodal Engineering,
Inc., an engineering consulting firm located in Denver, Colorado.
Ms. Reilly specializes in simulating the energy performance of
commercial buildings using the DOE-2.2 software. She provides design
assistance to a wide variety of clients, including the Federal
Energy Management Program at NREL, the National Park Service, and
private design firms throughout the U.S. She has recently completed
work on a large research facility for the University of Hawaii
Medical School, as well as analysis of a broad range of efficiency
strategies for laboratories in Minneapolis, Denver, Seattle and
Otto Van Geet is
currently the Senior Mechanical Engineer in the Site Operations
group at NREL, where he has worked on the planning, design, construction
and operation of facilities for the past 9 years. Prior to joining
NREL, he was a Mechanical Engineer for Sandia National Labs in
Albuquerque, New Mexico, for 11 years. Mr. Van Geet has been involved
in the design, construction, and operation of energy efficient
R&D facilities for microelectronics, photovoltaic, thermal,
and biological research, as well as office and general use facilities.
This has included integrated building design of clean rooms, supply,
exhaust, heat recovery and treatment systems, process gas systems,
safety systems, drain systems, fire protection systems, central
heating and cooling plants, lighting systems, and control systems.
Experience also includes passive solar building design, use of
design tools, photovoltaic system design, energy audits, and minimizing
energy use. He designed and built an off-the-electric-grid PV power
passive solar home in Colorado in which he and his family live.
Mr. Van Geet is a Registered Professional Engineer, a Certified
Energy Manager by the Association of Energy Engineers, and has
been designated a Project Management Professional by the Project
Management Institute. He received a B.S. degree in Mechanical Engineering
from the University of New Mexico and an A.A.S. degree in Air Conditioning
Technology from the State University of New York.