ASHRAE Journal - February 2013 - 54

Power (kW)

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Ki ote
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Q en ai
Re uic (c n
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au e
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au e
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au e
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Percentage

nology while providing justification for the
90
Total Fan Power Reduction (%)
financial incentives being offered within
Exhaust Fan Speed Reduction (%)
utility energy efficiency programs. The data
80
also supports the adoption of DCV techAverage Exhaust
Average Total Fan Power
Fan Speed
nology within energy codes and standards.
70
Reduction, 57%
Reduction, 26%
However, at this time, the authors do not
60
have published field monitoring data for the
temperature-sensing-only DCV systems to
50
be able to report on the energy performance
for this subset of DCV technologies. It is an40
ticipated that DCV system monitoring will
be ongoing and that data will evolve that
30
will characterize the performance of the
20
other DCV options on the market.8
As appliance-use sensing strategies and
10
DCV control algorithms evolve, along
with commissioning protocols, the authors
0
believe that the energy-saving potential of
DCV systems will increase and continue
to improve the return on investment for the
building owner. Just as appliances’ communication platforms advance to monitor temperatures, maintenance issues, on time and Figure 1: Average fan speed & fan power reduction for field monitored DCV sites.
product mix, the same information can be
used to establish exhaust rates based on which appliances are
5
Average
cooking what product and for how long. A plug-and-play type
Without DCV
sophistication would streamline the process to maximize hood
4
performance for a type of appliance/hood configuration, while
minimizing the fan and makeup air, tempering energy use.
3
Beyond the DCV system design and installation, the facility
Average
With DCV
management side must “take ownership” if DCV technology is
2
to be successfully deployed. Education of staff is a key ingredient
for a successful installation. If they don’t understand the value,
and existing hood problems are not fixed, they will quickly learn
1
how to override the system. The authors find in their food-service
fieldtrips that many DCV systems are working just fine, while
0
others have been overridden by one means or another. And we
0
2
4
6
8
10 12 14 16 18 20 22
Time
have also learned that effective fine-tuning during commissioning
of a DCV system can maximize its performance (which is often a Figure 2: Typical rear exhaust fan power profile for a campus
neglected piece of the commissioning specification).
dining facility.
While DCV has been a key measure incorporated within
3. Melink, S. 2003. “Kitchen hoods using demand ventilation.”
LEED projects, the authors believe that demand-controlled
ventilation is positioned to move from best practice to stan- ASHRAE Journal 45(12):22 – 26.
4. Consortium for Energy Efficiency. 2012. Commercial Kitchen
dard practice. But the journey is not over. Until the indus- Ventilation Demand Control Ventilation Field Test Protocol. http://
try adopts VFDs as an independent value proposition and the library.cee1.org/content/cee-ckv-dcv-field-test-protocol-version-10.
5. California Energy Commission (CEC). 2006. Public Interest
cooking equipment develops the “intelligence” to communicate with the DCV processor, the cost and performance limi- Energy Research (PIER) Program Case Study: Demand Ventilation
tations of DCV will continue to challenge the industrywide Control in Commercial Kitchens, UC Berkeley—Clark Kerr Campus.
adoption of the technology. We look forward to a future where
Acknowledgments
single-speed kitchen exhaust ventilation systems are history!

References

1. Food Service Technology Center. 1999. Outdoor Air Load Calculator, V1.3.
2. Fisher, D. 2003. “Predicting energy consumption.” ASHRAE
Journal 45(6).
54

ASHRAE Journal

The authors acknowledge Pacific Gas & Electric (PG&E) and
Southern California Edison (SCE) for providing the financial support
for the field monitoring reported in this article. We also recognize the
engineering team at SCE’s Customer Technology Application Center
(CTAC) who contributed to the technical content of this article and
are proponents of DCV application.
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February 2013

ASHRAE Journal - February 2013

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