once-through air. For speculative, generic or
“future flexible” lab programs it can be trickier
to make these decisions, as the HVAC infra-
structure needed to allow for local recirculating
air systems can be an expensive capital invest-
ment and require more space than typical all-
air once-through infrastructure.
Typical systems employed in spaces that can
safely allow air recirculation include fan-coil
units and chilled beams, both active and passive. These systems all have pros and cons relat-
continued on page 12
Pushing energy-efficient lab
continued from page 3
STAKEHOLDER ROLES AND RESPONSIBILITIES
The web of stakeholders involved in any medi-um- or large-sized lab project can be quite complex, and it’s important to anticipate the presence
of these people at sometimes unexpected points
during the life of the project. It’s equally important not to underestimate any one person’s ability
to influence the design or schedule. It’s for those
reasons that those responsible for delivering the
design and construction of these facilities get
ahead of the curve and campaign to bring these
players to the table early, at a time that allows
orderly communication of requirements, and
which minimizes the cost and schedule impact
of important requirements that might emerge
from these interactions.
TYPICAL AREAS OF CONFLICT
The opportunities for energy savings in
labs depends on the specific lab program. For
instance, the approach a designer might take to
design an energy-efficient, fume-hood-dense
chemistry lab and an internal heat-gain-inten-sive physics lab may be quite different. But in
the majority of cases, there are some usual suspects that arise and present opportunities for
enhancing energy efficiency, but also may pose
safety or other program risks.
Many labs require once-through ventilation to prevent
the buildup of potentially hazardous pollutants within the lab
that aren’t contained. Some lab
spaces are universally acknowledged as requiring once-through air, such as spaces predominantly for chemical fume
hood use, due to the high risk of
spills and other mishaps. There
are, however, many types of
spaces where the risks are much
lower and where recirculation of
air is commonly employed, such
as support rooms for specialized
measurement apparatus and
physics and material test labs.
The first target for reducing
energy consumption is typically
the judicious use of once-through air, as the
cost of cooling, heating and controlling humidity of outside air is vastly more expensive and
energy intensive. For specific or custom lab
programs, it’s generally a straightforward exercise to agree what areas do and don’t require
Figure 4: Typical sensible (glycol loop) heat-recovery system.
Figure 2: Chilled beam recirculation vs standard once-through air.
Figure 3: Variable fume hood exhaust based on sash position.