Large
investments by building owners in energy efficient
buildings, appliances, air conditioning/refrigeration
systems, and lighting are being made to reduce utility
cost, mainly electricity. The irony is that until we
take measures to actually conserve energy, not just
reduce our utility cost, will we be heading in the right
direction. For example, now that homeowners have
invested in PV systems their tendency is really to
consume more energy because the cost of energy is less
expensive, i.e., leave lights on longer, run the air
conditioning when no one is home, etc. We should
strive for the reduction in kw-hrs./month, the
real measure of energy usage. Or else, we are just
wasting energy efficiently.
For any
building, simple measures can be made to reduce the air
conditioning operating cost. These measures only take
simple training and the discipline to perform them
continuously, just as employees are taught friendly
greeting, polite and prompt customer service. These
measures could be the responsibility of the shift
manager or an appointed energy-miser czar, whose
responsibility is to always be aware of the temperature
set-point and overall comfort level of the customers.
Too many restaurants are freezing cold, mainly because
they are trying to keep the waitresses and busboys
comfortable as they actively move around to service the
tables. The priority of the air conditioning comfort
in restaurants should be for the dining customers’
comfort, all who are “non-actively” seated at the
tables.
Steps
to reduce air conditioning operating cost:
1.
Monitor
space temperatures daily. With a good, fairly accurate
thermometer (a handheld infrared is best; it reads
instantaneously) and a responsible person regularly
walking around to make sure the space is not overcooling
by too low a temperature set-point. Comfort temperature
range is 72-75F. For restaurants, the lobby entry may
be set at 72F to pre-cool the walk-in patrons; the
seating area should not be below 75F. THE GOAL IS TO SET
THE SPACE TO THE HIGHEST COMFORTABLE TEMPERATURE THAT
AFFORDS THE LEAST COMPLAINTS OF “TOO WARM”. According
to ASHRAE Application Manual Section 3.5 for restaurant
dining: Patrons entering from the outside are more
comfortable in a room with a higher comfort temperature
than those who find it too cold at first and have to
remain long enough to become acclimated. More
important, for each degree of warmer temperature saves
about 3-5% of energy consumption of the air
conditioning.
2.
Avoid
thermostat tampering (someone always changing thermostat
settings; a thermostats’ job is to maintain the
set-point temperature). This is one of the biggest
causes of high air conditioning operating cost. Install
locking thermostat covers if needed.
3.
Close
shades on all windows when exposed to direct sunlight.
4.
Set the
set-point with the thermometer not the thermostat
reading as it may be inaccurate.
5.
Check
air conditioning filters regularly to keep air clean and
prevent improper cooling.
6.
Clean
air conditioning condenser coils (outdoor) for maximum
energy efficiency. Just regular washing (once a month)
with fresh water keeps coil clean and prolongs coil
life.
7.
Where
possible turn off air conditioning and dim lights when
space is not in use.
8.
Make
sure all doors are closed to prevent conditioned air
from escaping.
All the
above can be done by employees and requires no outside
services or added cost of energy monitoring equipment.
Monitoring temperature continuously is as important as
continuously monitoring the food quality, as both
creates a lasting value to the customer. The
thermometer is the best assurance that the comfort
set-point is just right and not too cold.
To
start, if the normal set-point is way below 75F, you may
want to change temperatures slowly, maybe one degree a
week, so employees and customers will not notice the
change. For example, if the set-point was at 68F and it
is readjusted to 75F immediately, people will notice the
change and complain. Moving the set-point slowly will
allow acclimation with minimal complaints.
