here

CASE STUDY: Extrusion
Staying Consistent with
Integrated
Process Cooling
Extruder bolsters process cooling
capabilities to maintain quality, save costs
The Challenge:
Maintaining Consistent Temperatures for Extrusion
SELA, Inc., a producer of liquid sampling equipment and reusable plastic
drinking straws, needed consistent process temperatures for its three
extrusion lines and injection-molding process. Constant and exact
temperatures on the extrusion line ensure that the product has the
best clarity, especially when using a high-cost clarified resin or colorant.
Additionally, for SELA to increase throughput they must increase material
processing per hour, which generates more heat in its processes. By
upgrading its process cooling system, SELA would be able to increase its
throughput while controlling water temperatures.
When adding a third extrusion line to its plant located in South Carolina in
2007, SELA was looking to replace their air-cooled chillers to help address
their temperature concerns. SELA needed a system that would help
maintain a stable heat profile and deliver proper cooling capacity from
start to finish. Additionally, SELA did not want to add another air-cooled
chiller due to already high ambient plant temperatures.
As such, SELA sought an alternative process cooling solution to help
them achieve consistency and increase capacity and throughput while
maintaining product quality. It would also help them compete against
lower-cost competitors.
The Solution:
Finding Stability with Closed-Loop Process Cooling
SELA explored several cooling options, including a conventional
evaporative water tower. Ultimately, the company decided to install Frigel
closed-loop technologies on their extrusion lines and injection molding
system. The integrated system, which replaced two five-ton air-cooled
chillers, plus a smaller unit, included a 32-ton Ecodry central cooler, which
SELA at-a-glance
• Founded in 1983 to produce
liquid sampling devices for a
number of industries, SELA now
mainly manufactures a range of
reusable plastic drinking straws for
businesses worldwide
• York, South Carolina
• 6,000-square-foot facility with plans
to add another 7,000 square feet
CASE STUDY: Extrusion
Results include:
• Energy and water savings of approximately
$10,000 per year when compared to the alternative
setup originally considered. In all, water use declined
from approximately 25,000 gallons per month to
4,000 gallons per month, none of which is used for
process cooling.
• Increased throughput on the extrusion lines by as
much as 15 percent.
• Continued consistency in quality – in addition to
increased throughput.
• Maximum uptime due to decreased maintenance
and system redundancy.
Based on the initial results of the integrated system,
SELA chose to install a second, 32-ton Ecodry unit, giving
cools each of the three extruders and an injection molding
machine. The Ecodry unit supplies process cooling water
to Microgel single-zone chiller/TCU units located at each
the plant a total of 64 tons of capacity for more efficiencies
and anticipated cost savings, while also providing
increased redundancy.
extrusion tank and to a dual-zone Microgel chiller/TCU unit
dedicated to an injection molding machine that produces
straw tips.
All units provide SELA with the ability to use “free cooling”
when ambient temperatures permit. Free cooling means
the central cooler and the Microgels can provide water
at the proper temperature to processing equipment
without using compressors to generate chilled water. The
Microgel units automatically cycle off their compressors
to satisfy the cooling load at the exact temperature
requirement. This process allows SELA to achieve lower
energy consumption and cost savings, especially in the
humid south. SELA also chose the Microgel dual-zone
chiller/TCU based on its ability to satisfy both chilled, and
“Frigel’s deep understanding about markets in which water
if needed, warm water for specific applications.
is a vital resource has helped us find a system that will treat
water for our processes just as we need it,” said Ronnie
The Result:
Roberts, president and owner of SELA. “Frigel’s closedloop system allows us to maintain a stable heat profile,
The Ecodry and machine-side chiller/TCU machines provide
which allows us to increase our throughput and maintain
SELA with more consistent temperature control for their
the quality that we are known for in our product lines.”
processes while also eliminating water waste.
www.frigel.com