WEndI WInTERS
WashEs anD WE Won'T BuILD a
Wash WIThouT onE," DECLaRED
ChIP haCKETT, oWnER oF FouR
ExTERIoR ExPREss uLTRa CaR
Wash LoCaTIons In ThE aTLanTa,
gEoRgIa, aREa. Clearly, Chip hackett
is hooked on vFDs--variable Frequency
Drives. "We got into the business five
years ago. We focused on building the
business, but we've been focusing lately
on the expense side. We got the soaps
and water under control, but the big
gaping hole was in electricity and power
management."
all of the washes offer a low-priced
exterior wash and a free self-vacuum
service. Two more are under construction.
some sites have up to 35 vacuums, and
on a busy day 120 cars will pass through
the tunnels each hour. Just like the
vacuums, the tunnel blowers are going
non-stop when volume is high.
The vacuums are sucking up more
than just dirt. along with the blowers,
they are a major energy drain, sucking
up hackett's profits. With the help
of steve Tucker of autovac Industrial
vacuum & air systems in san Diego,
California, hackett has found a way to
dramatically lower his monthly power
bills.
vFDs," he said. "We have installed
them on our vacuum producers at two
of our locations. The vFDs monitor
the pressure within the vacuum system
and adjust the speed of the motors
accordingly to provide the right amount
of suction based on the number of users.
as a result, we are able to provide suction
on demand."
at full speed, a 25 hP motor operates
at 60 hz. In the case of hackett's ultra
Wash operations, when all hoses are
hung up, the vFD reduces the speed of
the motor to around 40 to 42 hz. This
is two-thirds of capacity and what is
needed to produce enough suction for
one user.
"The key here is that at 40 to 42 hz,
the power consumption is only 32%,
compared to the power used at 60 hz or
full speed," he explained. "as each hose
is dropped, the vFD ramps up the motor
hZ until it reaches 60 hz, when all hoses
are dropped."
Bottom line, hackett and Tucker
installed four vFDs at one location on 25
hP vacuum producers. There are several
ways to measure the results.
one factor that skews the results is
there are usually varying car counts each
month. however, at hackett's ultra Car
Wash locations where the vFD system
provides power on demand by constantly
communicating with all the vacuums
and blowers, peak KW has been reduced
15-20% since its installation. Electric
companies bill based on peak demand.
The "smart" vFDs that autovac installs
can cut peak demand usage, providing
additional savings.
Moreover, hackett said, overall
kilowatt use has been reduced by a
greater percentage, and, where the
Through Variable
Frequency Drives
electricity bill.
left was manufactured by Autovac and contains their VacuumIQ vfds. The cabinet on the
right is a custom mcc manufactured by Rockwell Automation for Smart Start RA. It contains
soft starts for all motors under 5hp and VFDs on all motors over 5hp. Center: The inside
of the custom motor control center with a close-up on the 70 hp vfd that controls the
blowers. This vfd provides the flexibility to change blower speed by wash package, idle
the blowers between cars, change blower speed based on outside air temperature and
operate blowers at an efficient level, all of which leads to significant (30%+) savings in
power and dramatically decreased peak demand. Bottom: The outside of the custom mcc
by Rockwell Automation/Smart Start RA.
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