EMAIL
INTERVIEW
– David W. Bearg and Ken Sinclair
David W.
Bearg, P.E. Environmental Health & Building Science Life Energy
Associates
With a combination of an educational
background in Chemical Engineering (a B.S. from Northeastern
University) and Environmental Health (an M.S. from the Harvard School
of Public Health), and over thirty years of experience in understanding
and resolving indoor air quality issues, Mr. Bearg has an in depth
understanding of what it takes to achieve a healthy indoor
environment. His definitive book, Indoor Air Quality and HVAC
Systems, was published in 1993. His current efforts focus on
Integrated Performance Assessments to determine whether the various
components of a building and its HVAC systems are achieving, or not
achieving, a healthy indoor environment. Key components of these
investigations involve assessments of ventilation and moisture
management performance.
“Autonomics”
A building can be
considered “Smart” or “Intelligent” if it can be self aware in the
areas of ventilation and moisture management performance such that it
both provides diagnostic information on performance in these areas and
even implement changes.
Sinclair:
What areas of Automated Buildings
are you involved with?
Bearg:
I am involved with what I call “Autonomics” where a building can be
considered “Smart” or “intelligent” if it can be self aware in the
areas of ventilation and moisture management performance such that it
both provides diagnostic information on performance in these areas and
even implement changes in HVAC operation. This “intelligence” can
then complete the feedback loop in making sure that the operational
performance is actually achieved in these areas that are critical for
the achievement of healthy indoor environments.
Sinclair: What do you see as the biggest
challenges for achieving this goal?
Bearg:
One challenge is the need to have accurate enough data in the areas
of ventilation and moisture management performance so that the
sophisticated software analytics can provide meaningful operational
instructions for the automatic control of the HVAC system. The
quality of the action taken here can be no more accurate than the
quality of the data being input into the software. The term,
“Garbage In, Garbage Out” (GIGO) comes to mind. If accurate data
in these areas becomes available, a better job of optimizing building
performance can be achieved, not only for energy use, but for healthfulness
as well.
Another challenge is that too many people seem to think that designing
a building to comply with ASHRAE 62.1 minimum ventilation rates is
sufficient to achieve good IAQ. The reality, however, is that the
goal of this Standard is to have no more than 20% of those exposed
dissatisfied. Providing greater amounts of ventilation have been
shown to reduce short term absentee rates due to more rapid dilution
and removal of cold and flu viruses.
Another challenge is that too many myths and misunderstandings exist about how to achieve good indoor air quality and so
decisions that impact ventilation effectiveness, such as the geometry
of the airflow through the occupied spaces, the amount of ventilation
to be provided, and how this ventilation will be controlled fall short
of achieving this goal.
Sinclair:
Can you give an example of a
typical control-based ventilation shortcoming?
Bearg:
Yes, the use of VAV boxes controlled by thermostats in conference
rooms. In this situation the occupied space becomes overcooled
during unoccupied intervals when the VAV box is at its minimum and then
after occupancy there is a time lag until the thermostat experiences
the needed “rise in temperature” to increase the amount of supply air
and ventilation. The result here is the early part of the meeting
is severely under-ventilated. I’m finding this under-ventilation
to be occurring almost everywhere I look for it, so there needs to be a
better way of providing ventilation in variable occupancy
locations.
Sinclair: What techniques have you seen
working to achieve this goal?
Bearg:
One approach to provide accurate and reliable data on both
ventilation and moisture management performance is the use of a
shared-sensor monitoring systems. In this approach, a network of
sampling lines are installed and the monitoring system automatically
and sequentially draws air from key locations and brings this sampled
air to a central location where both carbon dioxide and absolute
humidity are measured using laboratory grade equipment.
Sinclair:
What developments do you see in
the future evolution of Autonomics?
Bearg:
One possibility is that a major player decides to move into this area
of accurate monitoring and creates the next generation of shared sensor
monitoring systems bringing about a reduction in costs as well as
increase in software analytics to be the brain behind a more
intelligent building. When this happens, risk and uncertainty in
building operations can be reduced and building occupants will get the
benefits from healthier and more productive indoor environments.
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