Monitoring Lab Energy Usage
Labs are energy guzzlers, but efficient energy
monitoring can help reduce energy usage.
Laboratories are notorious for their extraordinary energy consumption, often using six to 10 times the amount of energy of a normal office facility. As more
and more attention is given to reduce lab energy use, it
becomes increasingly more important to understand the
energy drivers in labs to better target energy-conservation
measures and improve occupant behaviors. Lab energy
monitoring gives facility personnel the insight they
need to identify lab energy use, implement effective
energy reduction strategies and monitor ongoing energy
consumption to ensure lower-energy labs stay that way.
Lab energy consumption can be broken down into a
relatively small number of categories: lighting, plug load and
heating, ventilation and air conditioning (HVAC). Lowering
the energy consumption within each of those categories
involves decision making around one or more strategies:
improving the efficiency of the equipment itself, improving
the effectiveness of the related controls for those devices or
focusing on improving the behavior of lab occupants. But
which combination of focus areas and strategies will yield
the best return? Energy monitoring can help sort out the
Energy monitoring and airside efficiency
HVAC energy consumption is by far the largest
subcategory of building energy use, so identifying ways
to optimize the airflows in a lab will often have the
largest impact on a lab energy-reduction initiative. One
complicating factor, however, is that airflow in a lab is
used for different purposes. In addition to regulating the
temperature by providing the proper amount of heating or
cooling, additional supply air might be needed to meet the
needs of fume hoods in a lab, and even more air might be needed
to achieve a minimum dilution of air for lab occupants, particularly
when there are benchtop procedures being performed.
Figure 1 shows an “energy driver” mapping of several different labs,
making it easy to see what percentage of time each lab is driven by
thermal, fume hood or dilution requirements—as well as the amount
of time the lab is running at design minimum flows.
Lab areas driven by their thermal load may be good candidates for
lighting, plug load and occupant behavior programs to reduce any
unnecessary equipment use driving this requirement. Similarly, labs
driven by their fume hood usage can be further reviewed to determine
if sashes are properly managed (an occupant behavior program), or to
consider implementation of a more efficient fume hood strategy (an
equipment/controls-focused program). Once again, energy monitoring
can provide information to guide that determination.
The use of visual data helps sort a tremendous amount of
information into something that can be easily understood. Knowing
the sash is open right now doesn’t help identify whether the sash
is managed properly, since a lab researcher could be conducting
a procedure in that fume hood. However, knowing what the sash
position has been over a week or more helps determine if that sash is
opened only when needed. Looking at Figure 2, it’s easy to see some
sashes have been in a full or partially opened position for an entire
week—probably longer than most researchers spend standing in front
of their fume hood.
Using information to align energy and safety objectives
When airside efficiency discussions begin to focus on
determining the “most appropriate” air change rate for lab dilution
purposes, a battle is often in the making between facility managers
and lab safety personnel. The most common (mis)perception is
Figure 1: This energy dashboard shows which labs are driven by heat load, fume hood demand or dilution
(lab activity) requirements. Lab 3132 has been running at design minimum flows. Images: Aircuity Inc.
Figure 2: This sash management display shows the average sash position for fume hoods in a lab.