March
2017
Column
AutomatedBuildings.com
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Ira Goldschmidt, P.E., LEED®AP
Engineering Consultant,
Goldschmidt Engineering Solutions
ira.goldschmidt@comcast.net
ASHRAE’s standard
90.1’s goal to progressively reduce building energy usage has resulted
in the steady introduction of additional requirements to each new
version of the standard. In more-recent versions, added
requirements for the use of DDC controls along with the use of control
sequences such as economizers (air and water-side, and most recently,
with “self-diagnostic” capabilities), optimum start, demand-controlled
ventilation, reset of duct/pipe pressure setpoints for variable volume
systems, single zone AHU’s and the fan-powered sections of VAV boxes
can no longer be constant volume, etc.
However, through the 2013 version, these have essentially applied to
only “new” construction. Further, many of these “sequence”
requirements have started to become standard practice for building
design and construction. Therefore, the effect on the controls
market has been minimal (or even for the worst given its possible
negative effect on controls contractor’s profit margins).
But the latest 2016 version of 90.1 has expanded its scope to include
remodels/additions to existing buildings. The possible effect of
this on demand for DDC controls (and BAS’s) could be enormous given the
number of existing buildings that don’t meet the more-recent controls
requirements of 90.1.
Let’s look at the two possibly defining examples of the controls impact
from 90.1’s expanded scope to include existing buildings:
VAV Boxes
I am not aware of
any data regarding the quantity of pneumatic VAV box controls that are
still in use; however, I would guess it to be quite many…as in perhaps
millions? The requirement to upgrade these controls could finally
be the “nail in the coffin” for a major source of building discomfort,
increased energy consumption, limited building operating information,
etc.
The actual interpretation and enforcement of what work constitutes
“remodels/additions” (i.e., will every “tenant finish” project big or
small be included) will determine whether pneumatic VAV box controls
will continue to be replaced slowly or will the effect be to
exponentially increase the replacement work (along with the demand for
DDC VAV box controls). I hope it is the latter.
Single Zone RTU’s
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Packaged
single-zone RTU’s (with constant volume fan operation and air-cooled
DX) are one of the last major impediments to energy efficiency
improvements in existing light commercial, retail, etc.
buildings. Here too there are also probably millions of instances
of this type of equipment still in use. Of course, merely
changing an existing RTU to VAV is not the only (or most important)
step needed to improve their energy efficiency (i.e., there’s probably
more to be gained by improving the DX system). Further, it may
not always be possible to merely change an existing RTU to VAV due to a
DX system’s inability to handle the reduced air flows. Finally,
the added requirement for properly-operating and self-diagnosing
economizers only ups the ante.
So it is possible that 90.1’s “no more constant volume” requirements
could lead to not only an explosion in need for more advanced RTU DDC
controls but in the wholesale replacement of RTU’s using “old”
technology?
Closing Thoughts
Of course, the extent of this potential controls “explosion” will depend on:
• How 90.1 is adopted by local code authorities
(i.e., directly, or indirectly and with different
language/interpretations via the IECC or Title 24),
• When it is adopted (i.e., widespread adoption could be spread out over many years), and
• How diligently it will be enforced which is always
going to be an issue for something like control sequences that are
difficult to “see.”
But no matter how
this all unfolds I see this change to 90.1 to be great news for
energy-efficiency in general, and the DDC controls market specifically.
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