Restaurants Energy savings
Eating up
waste
In-depth monitoring of one of its restaurants enabled
Pizza Hut to trial new energy-saving measures as part of
a refurbishment project. Carina Bailey reports
A
mid rising energy costs across its chain half an hour, but you’ve no idea where it’s gone. To
of restaurants, Pizza Hut decided it was establish exactly which devices were using the most
time to investigate where its energy was power, we needed to look at the sub-circuit level, and
being consumed. A store in Watford, this is where more detailed sub-circuit monitoring
Hertfordshire, was chosen as a test-bed for assessing comes in.’
wasteful energy consumption. The circuits chosen for monitoring included the
An energy monitoring system, NoWatt, was installed air conditioning in both the dining and kitchen areas,
in the store in April 2008. The system measured cooker hood supply and extract fans, lighting circuits,
consumption every 30 seconds. ‘Originally, Pizza and walk-in fridge and freezers. Within a matter of
Hut had half-hourly data, which makes analysis of days, Groves could see that about 72kWh of electricity
individual items like looking for a needle in a haystack,’ per night was being wasted because the aircon system
Pizza Hut’s Watford Dome
site has become a regular
says Richard Groves, who conducted the study for was not switching off after the store closed. One quick
place for testing new products
consulting engineer AECOM. call to the maintenance company to reprogramme the
and services. ‘This only tells you that you’ve used, say, 20KW, in time clocks resulted in this level of energy saved each
night.
Monitoring also revealed that one of the aircon units
was not providing any cooling at all, which could be
seen by the constant 3kW load on the kitchen aircon
sub-circuit – which Groves knew, from the technical
manual, was the consumption of the fresh-air fans.
Another problem was the exterior and signage
lighting was defaulting to ‘on’ when it was only supposed
to be providing power to the circuit between 3pm and
midnight, with a photocell turning on the lights when
it was getting dark. This resulted in 41kWh of electricity
being used. This was repaired, but the monitoring
showed it failing again a few months later.
This time, the sub-circuit was monitored, and
Groves was able to see the electrical contractor testing
the switching of the circuit. ‘We were also able to see
that they had not left the circuit set up correctly, and
36 CIBSE Journal March 2010
www.cibsejournal.com
CIBSEmar10 pp36-38 pizzahut.indd 36 2/25/10 5:36:09 PM
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