Brochure

Velocity Gradient of Water in a Rolairtrol
The picture to the right illustrates the velocity change for water passing
through an RL Rolairtrol. A computational fluid dynamics program, using
color to depict the changes of fluid velocity and flow path within the
Rolairtrol vessel, was used to create this illustration. The green color
indicates the higher velocity fluid; the dark blue a low velocity fluid. The
Rolairtrol uses a combination of low velocity and centrifugal action to help
separate entrained air from the water. The difference in density of the two
fluids forces the air toward the low velocity area in the center, where it
rises to the top of the vessel and accumulates in the air collector. The
air then passes through an air vent and is vented to the atmosphere
or it is directed to a compression tank.
Scales Hall,
Southwestern Adventist University
Low VelocityHigh Velocity
Reduced Life Cycle Costs
No doubt, when operated at manufacturer’s recommendations, the
pressure loss of an air separator in a hydronic system will be very low
compared to the rest of the system. When the Rolairtrol is operated
at the same flow rate recommended for the competitors units, not
only does first pass efficiency increase, but operating costs are also
significantly reduced. Pumping costs of a Rolairtrol can be from
50% to 25% of competitive devices. That helps make attaining green
energy design guidelines easier for the designer. Considering that
many competitive units are more expensive than the Rolairtrol, and
that the Rolairtrol costs less to operate and has better air removal
performance, the Rolairtrol just makes good sense!
9
Scales Hall on the campus of
Southwestern Adventist University
is a long, low building. Therefore its
combination heating/cooling system
has little static height and long pipe
runs. The system often experienced
pump noise and air bound circuits
causing poor performance in both the
heating and cooling modes. When it
came time to replace the original cast
iron boiler, Putnam Services searched
for a better solution to control the air
in the system and reduce operating
costs. They installed a new boiler and
selected a Bell & Gossett Rolairtrol to
act as the air separator on this retro t
project. They were pleased with the
results. The complaints about uneven
heating and pump noise went away.
The ef ciency and performance of
Scale Hall’s hot and chilled water
system both improved. “We’ve never
had to run the boiler on full,” says
Jere W. Putnam, President of Putnam
Services, “the 1.2 million BTU boiler
only needs to be run on 800,000 BTU’s
and our 120-ton chiller operates at
only 60 ton.” The Rolairtrol proved
to be the solution for getting the
suspended air out of Scales Hall’s
chilled and hot water and providing
better overall heat transfer.