Water-Saving Solution for Chilling Plastics
Posted: November 3, 2007
A new chiller system has helped a plastics manufacturer reduce water costs and meet
increased production demands.
Goex Corp., a manufacturer of rigid plastic sheet and roll stock products based
in Janesville, Wis., was spending more than $100,000/yr on city water to cool the
cylinders used in its sheet-extrusion process. The company knew there had to be
a better solution.
City water lines ran in a tunnel beneath Goex’s building and served 12 sheet- extrusion
machines in the plant. The extrusion machines operated anywhere from 120 to 200oF
(49 to 93oC), and the chill rolls used water to cool the output sheets in stages
down to 60oF (16oC). Temperature control was crucial to ensuring consistent product
quality. Each plastic-extrusion machine had its own control valves and heat exchangers
to control the process. As business expanded and Goex increased its output capacity,
the plant became one of the city of Janesville’s largest municipal water customers
-- at a significant expense to the company.
To find a way to reduce its dependence on city water, Goex turned to Multistack,
based in Sparta, Wis. Goex had four main goals:
- To reduce its dependence on city water.
- To install a system that would ensure redundancy.
- To have the ability to expand the cooling system in the future.
- To save money long-term on operating costs.
After an evaluation of the entire process, Multistack presented Goex with three
possible solutions. The first was to install an air-cooled system that would sit
outside of the building. While this option would have completely eliminated the
plant’s dependence on city water, the operating costs were substantial.
The second solution was to install a water-cooled system inside the building with
cooling towers outside. This was the most expensive of the three options and also
would have increased the plant’s maintenance costs.
The third solution involved installing a water-cooled system inside the building
with city water cooling on the condenser side of the chillers. This system was the
most efficient and least expensive of the three options. While this solution would
not totally eliminate the plant’s dependence on city water, it would substantially
reduce its water consumption.
Four compressors and a dual-pump package were installed as a self-contained system
at plastics extruder Goex Corp. The system gives the plant 100 tons of cooling capacity.
A Redundant and Cost-Effective Approach
Goex chose the third option to cool its sheet-extrusion lines. The system installed
in the plant consists of two MS50Z chiller modules with a pump module that gives
the plant 100 tons of cooling capacity. The equipment supplies chilled water to
the production loop to chill the sheet-extrusion machines.
Four compressors and a dual-pump package were installed as a self-contained system.
The system’s redundancy helps the plant’s extrusion process run smoothly and ensures
consistent product quality. The chiller and water-pumping system have built-in redundancy
to ensure chilled water flow in the event of a compressor or pump failure. A second
set of water lines running parallel to the existing city water lines was installed
in the tunnel for the chiller system. These extra lines allow for city water backup
if the Multistack system has to be pulled offline for maintenance or if the plant
has an increase in production that requires more chilled water than the 100-ton
chiller system can support.
Once put in operation, the new system increased Goex’s electricity costs by about
$15,000/yr; however, it reduced the plant’s water costs to approximately $40,000/yr.
In effect, Goex cut its total utility costs in half. With these economic results,
the company will realize a payback on the system in less than two and a half years.
Since the Multistack system has been implemented, Goex has added production processes
and increased its plant output. The company has had to use the city water backup
in addition to the cooling system to meet increased cooling requirements, and it
is now looking into adding another chiller module. The system has run seamlessly
for Goex and is the solution the plant needed for the long term.
Multistack manufactures chillers and cooling products. For more information from
Multistack, call (608)366-2400; e-mail info@multistack.com or visit www.multistack.com.
For more information from Goex Corp., call (608) 754-3303; e-mail goex@goex.com;
or visit www.goex.com.