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A Case Study on the Dynamic Variation of Air Change
Rates in a University Research Laboratory
John D. Spengler, Ph.D.,
Harvard School of Public Health
Gordon P. Sharp, Aircuity, Inc.
Leith Sharp, Harvard Green Campus Initiative
At the 2005 Labs21 conference a unique approach was
presented to dynamically vary the minimum air change rates of a
lab room based on real-time measurement of the lab room's air quality.
Per this concept, rather than dilute clean air with clean air the
minimum air change rate of the lab room is reduced to a low level
such as 4 ACH occupied and 2 ACH unoccupied for measured clean air
conditions. Under a spill condition, or improper use of chemicals
outside a hood, the air changes are increased automatically to higher
than normal conditions such as 15 ACH to provide significantly increased
dilution. A design analysis was also presented that was done for
a lab project under design in Seattle that showed this approach
would create a 20 percent reduction in building energy costs as
well as a $1.05 million reduction in gross first cost from downsizing
the HVAC capital equipment.
The Harvard School of Public Health was interested
in evaluating the safety, efficacy and potential energy savings
of this concept for potential use in their lab facilities. As a
result a small operating lab floor consisting of two large open
bay labs plus some support areas and corridors were retrofitted
with the appropriate sensing and controls required for this concept.
Additionally, the lab rooms were heavily instrumented with multiple
air sampling/sensing locations to provide actual data on the propagation
time and spread of chemical vapors in these rooms for different
release conditions.
The presentation will discuss the results of the research
on this concept from these labs covering such topics as lab chemical
vapor propagation, normal operating lab air quality data, and dynamic
air change rate control performance under actual and simulated upset
conditions as compared to operation at a fixed air change rate.
Labs21 Connection:
Modulating laboratory air change rates based on the sensed indoor
environmental quality represents a paradigm shift that can have
significant impact on lab energy consumption and safety. With minimum
air change rates rather than hood makeup air or thermal load requirements
often being the dominant factor determining today's lab air flow
volumes, this concept is potentially relevant to increase the energy
efficiency of both current and future lab designs as well as many
existing facilities.
In keeping with the Labs21 approach, which encourages a holistic
view, this dilution ventilation control concept can also decrease
both system first costs and life cycle costs by reducing the average
air handler and design peak airflows allowing a downsizing of the
HVAC equipment at the main system level. Additionally, vivariums,
with design rates typically at the level of 10 to 20 ACH, represent
an even greater opportunity for energy and first cost savings with
the potential for typical operating air change rates as low as 6
or 8 ACH that can increase when needed up to 15 to 20 ACH for greater
dilution performance. In summary, a dynamic air change rate approach
can maintain occupant safety while furthering the goals of sustainable
laboratory design.
Biographies:
John D. Spengler, Ph.D., is the Akira Yamaguchi Professor
of Environmental Health and Human Habitation, in the Exposure, Epidemiology
and Risk Program, Department of Environmental Health, at Harvard
University's School of Public Health, Boston, Massachusetts. Prof.
Spengler has conducted research in the areas of personal monitoring,
air pollution health effects, aerosol characterization, indoor air
pollution and air pollution meteorology. In addition, to his academic
and research activities, Professor Spengler has been active in professional
education workshops and short courses on topics that include pollution
prevention and indoor environmental quality management for schools,
offices and hospitals, and distance learning courses. He is co-editor
of three books: Indoor Air Quality Handbook; Particles in Our Air:
Concentrations and Health Effects; and Indoor Air Pollution: A Health
Perspective. He is on the editorial board of the journal Indoor
Air, and he is the President (2002-2005) of the International Academy
of Indoor Air Sciences.
Prof. Spengler is a member of the International Society of Indoor
Air Quality and Climate (founding member), the International Society
of Exposure Analysis (founding member), the International Academy
of Indoor Air Sciences (founding member, President 2002-2005), the
American Society of Heating, Refrigerating & Air-Conditioning
Engineers (ASHRAE), and the American Meteorological Society. Currently,
Prof. Spengler is a chair of the National Research Council (NRC)
Committee on Review and Assessment of the Health and Productivity
Benefits of Green Schools. He has also served on ASHRAE's Environmental
Health Committee (2000-2003), the NRC Committee on Air Quality in
Passenger Cabins of Commercial Aircraft (2000-2001), the American
Lung Association's National Air Conservation Commission (1997-1998)
and on the Scientific Advisory Panel of the Mickey Leland National
Urban Air Toxics Research Center (1995-1998). He serves as an advisor
to the World Health Organization on indoor air pollution, personal
exposure and air pollution epidemiology, and he has served as either
a member or consultant on various U.S. EPA Science Advisory Board
committees. In 2003, Prof. Spengler received a Heinz Award for the
Environment.
Dr. Spengler received a B.S. degree in physics (1966) from the
University of Notre Dame, a Ph.D. degree in atmospheric sciences
(1971) from the State University of New York-Albany, and a M.S.
degree in environmental health sciences (1973) from Harvard University.
Gordon P. Sharp has over twenty
five years of wide ranging entrepreneurial experience and more than
20 U.S. patents to his name. From 1979 to 1985, he was vice president
and co-founder of IMEC Corporation, a motor controls technology
company from which he created a spin off company called the Phoenix
Controls Corporation. As president, CEO and founder of Phoenix Controls,
Mr. Sharp led the development of a $25 million venture capital backed,
world leader in laboratory airflow controls that was honored for
three consecutive years by INC magazine as one of the 500 fastest
growing private companies in America.
In early 1998 Phoenix Controls was acquired by Honeywell, Inc.
Thereafter, in addition to participating in restructuring the Honeywell
Home and Buildings Solutions business, Gordon led development of
the Honeywell business unit now known as Aircuity.
In January of 2000, Aircuity became an independent, venture capital-backed
company and today, is the leading manufacturer of a portable monitoring
system and a permanent facility monitoring/control system. Aircuity's
goal is to optimize building ventilation for energy efficient performance
without sacrificing occupant comfort, health or productivity. Mr.
Sharp is the chairman and founder of Aircuity and a graduate of
MIT with bachelors and masters degrees in electrical engineering.
Leith Sharp established the Harvard
Green Campus Initiative (HGCI) in March of 2000, becoming the Director
of this emerging organization. Leith also co-instructs the Harvard
Extension School course, Sustainability - The Challenge of Changing
Our Institutions. Leith has a Bachelors degree in Environmental
Engineering from the University of New South Wales and a Master
of Education in Human Development and Psychology from Harvard University.
Leith has worked with universities for the last 10 years to achieve
organizational change in the pursuit of environmental sustainability.
In 1998 Leith was awarded Young Australian of the Year, NSW Environment
Category, for her work in establishing the Environmental Management
Program at the University of New South Wales, Australia. In 1999
she was awarded a Churchill Fellowship to research best practice
in university environmental management throughout Europe and the
U.S. In 2002, Leith was awarded most outstanding paper for her contribution
to the International Journal of Sustainability in Higher Education.
Leith has presented at many conferences and events across the U.S.
and Australia.
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