Maximize Efficiency in Commercial Buildings
Are Your HVAC Controls Helping or Hurting?
Sophisticated controls can be a great way to boost the nergy efficiency of your HVAC system, but if they’re not installed properly or used correctly, you may end
up wasting energy without realizing it.
Issues with building controls are
frequently the result of human error,
explains Kevin Callahan, product owner
for Alerton, a Honeywell business that
specializes in building automation systems. Scheduling and setpoints are t wo
of the biggest opportunities for mistakes.
For example, an FM might override the
allowed temperature range in response
to an occupant complaint about a space
that’s too hot, only to forget to restore the
original setpoint later and waste cooling
energy in the meantime.
Are your HVAC controls doing their
job? Consider these tips to ensure they’re
still working as intended.
1) Look for Overrides
If all of your controls appear to be
functional – an important first step that
control software can help confirm – your
next move should be to review the settings for temperature and operational
schedules to see if an adjustment has
occurred. Nearly all control packages
track user activity within the soft ware,
Callahan says. If every member of your
team has their own unique user ID and
password, it should be easy to track down
the source of the override.
“You can see whether the setpoint
was changed by a certain person. Some
products even have a feature that forces
the operator to put in a comment as to
why they changed something in order
to complete the override,” explains
Callahan. “The comment should be a
justification such as ‘This was changed
by request of the occupant’ or ‘This set-
ting was changed for testing purposes.’
Then you have an audit trail to explain
why things were changed. If someone
just types gibberish in the comment
field, you can go back to that person for
You can also designate specific privi-
leges and capabilities for different users;
for example, giving the whole team
the ability to see control settings and
consumption data, but only allowing a
handful of trusted colleagues to change
2) Program for Problems
If the issue doesn’t lie with the controls
themselves or the people operating them,
“Now, every time I run that air con-
ditioning unit for at least 15 minutes, I ex-
pect the discharge temperature to be 53
degrees,” Callahan adds. “If it’s 60, that
tells me something is not right and the
building operator should go check that
unit. Write programs to look for expected
behavior, and then if that expected
behavior doesn’t happen, the system can
signal the operator of a pending issue.”
3) Check End Devices
Over time, wear and tear on moving
parts can stop equipment and controls
from communicating properly, Callahan
“The linkage on a damper actuator
could loosen over time from vibration
or not being tightened enough. Eventually, the linkage bet ween the damper and
the actuator loosens so much that the
actuator is moving but the damper isn’t,”
says Callahan. “That’s going to cause the
system to work harder than it should,
resulting in occupant discomfort and
Janelle Penny janelle.penny@buildings.
com is senior editor of BUILDINGS.
HVAC CONTROLS can trim considerable energy
waste as long as they’re operated correctly.
Check on your controls periodically to maintain a
high performance level.