Plastic Cooling Tower Six-Packs Address Issue of Cooling Capacity
February 24, 2010
cooling towers – now available in 2, 4 and 6 “packs” - meet the high
capacity cooling requirements of the manufacturing, petrochemical, pulp
& paper, plastics and metalworking industries.
many years, modular plastic cooling towers have suffered from a virtual
Napoleon complex – overcompensating for its smaller cooling capacity by
providing leak-free, rust-free, highly efficient operation with low
maintenance requirements, minimal use of consumables, and unheard-of
15-year factory warranties on some models.
molded plastic cooling towers are no longer the small kid on the block.
Previously limited to smaller cooling applications in the 250 cooling
ton range, these molded plastic cooling towers are now available as
integrated, multi-cell 2, 4 and 6 “packs” that work as a single system
and can provide cooling capacities from 500 to 2,000 cooling tons.
is welcome news for many broad based manufacturing industries including
petrochemical, pulp & paper, plastics, chemical, metalworking and
many other industries that previously had to rely on less durable metal
cooling tower construction as its only option.
evolution of the classic molded plastic cooling tower into the modular
system offers a very attractive solution for many industries that need
higher cooling capacities for larger, more demanding applications,”
says John Flaherty, president of Delta Cooling Towers (Rockaway, NJ).
modular systems, available in arrays of 2, 4 and 6 cells, offer a
scalable, cost-saving alternative to traditional welded, riveted or
gasketed metal towers for manufacturing, petrochemical, pulp &
paper, metalworking, and other industries, as well as many commercial
and institutional facilities,” he explains.
key to increased cooling capacity is its configuration. Manufactured
and assembled at the factory, modular cells interlock as a single
system. Each cell includes an independent seamless basin, but all cells
are “equalized” by plumbing connections that keep the overall water
they often work together to cool a specific application, the modular
cells can be split so that they handle more than one function. For
example, a 6-pack can be configured so that four cells handle process
cooling while two units handle HVAC support. Because of this
flexibility, they can also be shut off when not needed. For instance,
those cells that are used for HVAC support can be shut off during
colder winter months.
of all, they offer all the advantages of the seamless plastic cooling
towers that were innovated by Delta Cooling Towers in the 1970s,
including much longer life cycles, minimal maintenance, vastly reduced
risk of costly downtime and substantial savings on water treatment
Seamless vs. Panels
linings (fills) are the bane of many cooling towers applications. In
the classic metal-clad designs, galvanized panels of sheet metal are
welded together to form a water-tight vessel. However, the impending
corrosion of welded seams due to water treatment chemicals and
environmental factors can rapidly lead to leakage and other operational
problems. Even stainless steel basin welds routinely fail, due to under
deposit corrosion or water chemistry fluctuations.
tower leakage is particularly disruptive, requiring not only extensive
tower repair maintenance and replacement, but also the rebuilding of
damaged tower decking and supports as well as roofing and other plant
an increasing number of applications, the ideal solution for avoiding
all those maintenance, replacement and downtime costs is the seamless
molded plastic cooling tower. This design features a seamless, molded
shell composed of engineered plastic, rather than individual panels
that have to be fitted and welded or sealed with gaskets.
other plastic cooling towers have been available for some time, most of
those are also composed of many individual PVC or fiberglass panels.
However, while impervious to the corrosion that plagues metal linings,
leakage is still a problem because plastic panels are joined with
gaskets or seals that are subject to the stresses of expansion and
contraction that occur with temperature changes caused by weather or
cooling towers fabricated of individual panels, seamless plastic models
are factory assembled. This eliminates the need to hire and transport
construction crews to construct towers in the field.
can make a major difference in installation costs as well as downtime,”
explains John Flaherty. “Factory-assembled plastic cooling towers are
virtually a drop-in installation, requiring only hours to install
rather than days or even weeks. So, the savings on labor,
transportation and process downtime can be very significant.”
More Economical Operation
towers of seamless engineered plastic can also reduce the expenses of
operating costs, which include: electric power usage, water-treatment
chemicals, labor and materials for maintenance, and unscheduled process
downtime for cooling repairs.
and repairs usually means process interruptions, the costliest issue
associated with cooling towers. Given their short lifespan, metal-lined
models inevitably invite such interruptions in operations, while
corrosion-proof plastic cooling towers are more likely to provide
continuous and reliable operation.
instance, the “white rust” that forms on galvanized towers operating at
pH higher than 8.0 can quickly lead to failure and replacement
requirement. On the other hand, the use of engineered plastic allows
the use of better scale inhibitors that operate at higher pH.
impervious to pH levels and mineral deposits, engineered plastic
cooling towers can operate at higher cycles of concentration, leading
to operational savings. Higher cycles of concentration are achieved by
lowering the amount of blowdown or bleed-off of recirculating water.
Conceivably reducing bleed-off by 50% would also allow a 50% reduction
of chemicals for scale and corrosion control for process equipment
downstream from a conventional metal-clad cooling tower. In many
applications this chemical savings can exceed $10,000 per year.
use of more efficient direct-drive motors also improves both
reliability and operating efficiencies of cooling tower fans and can
result in substantial power savings throughout the year. Not to
mention, the costly downtime and disruption that is caused due to belt
replacement or failure in a belt driven fan cooling tower.
Ease of Installation
of the difficulties associated with cooling tower installation or
replacement is the need to support heavy loads. Delta Cooling Towers
solved this problem with its TM Series, a modular, lightweight design
that includes a self-supporting base with I-beam pockets, enabling
users to install up to six cooling tower modules on a simple I-Beam
support structure utilizing a relatively small footprint.
a more attractive, less “industrial” appearance, the smaller footprint
of these modular cooling towers may be an ancillary benefit for
commercial applications such as shopping centers, schools, hospitals
and office buildings.
—By Ed Sullivan
Ed Sullivan is a technology writer based in Hermosa Beach, California