The crux of efficient air travel is the ability of airlines to refuel
aircraft efficiently and economically and keep aircraft moving.
Airport operators have all but mastered fast refueling capabilities,
providing fuel pumping systems that can offer as much as
16,000 gallons per minute, depending on an airport’s size,
and refuel planes in as little as 15 minutes.
Efficiency comes at a cost for many airports that use the traditional
constant speed hydrant pumping system. These systems are
designed to provide fuel at the pressure and volume needed during
peak times. The only way to reduce that
pressure during off-peak times
is to throttle it back by using
control valves that cycle fuel
back through to the storage
tank while the motor continues
to operate at top speed.
Prime Time for VFD Systems
Makes Refueling Aircraft
By John Bagnall, PE
This wastes energy — and, in essence, money — by constantly
running the motor at full speed. It also puts unnecessary wear and
tear on equipment. Both of these directly affect maintenance costs
and could lead to a premature need to replace a pumping system
altogether. Additionally, the sudden pump start to the peak-time
pressure rate in older systems can cause a power surge for the
power utility company’s system because the constant speed
hydrant system does not have a gradual pump start option.
Variable frequency drives (VFDs) could eliminate virtually every
negative aspect of traditional fuel pump systems. VFDs work
by speeding up and slowing down the motor to control the fuel
pressure rather than keeping the motor at a constant higher speed
and throttling it back with control valves.
The motor and pump are direct-coupled, so that the speed of
the motor equals the speed of the pump. As the demand for fuel
rises and falls throughout the day, sensors tell the motor when to
increase speed, and thereby pressure, and when to back off.
Because the motor isn’t constantly running the pump at full
throttle, energy consumption can be reduced to an eighth of
the energy used for a constant speed system, and the pressure
is customized based on need. There is less wear and tear on
equipment, and the VFDs can start gradually, lessening the sudden
shock the power utility would otherwise encounter during startup.
VFDs are the current standard for airport fuel
pump systems and have been used in Europe for
the past 20 years or more. Yet only a handful of
airports in the United States have installed this
Until recently, the cost of installing a VFD
system could not be justified. A 20-year return
on investment rate didn’t make fiscal sense,
especially if an already-in-place constant speed
system functioned properly and had plenty of
SmartVFD HVAC, BYPASS and COMPACT variable frequency drives (VFDs) are designed specifically for commercial use,
with 98 percent efficiency and minimal labor. VFDs monitor the system constantly, automatically adjusting for optimal energy
use, and include labor-saving features for accurate commissioning and reliable maintenance.