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 200°F (49 to 93°C), and the chill rolls used water to cool the output sheets in stages down to 60°F (16°C). 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.
A Redundant and Cost-Effective ApproachGoex 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 firstname.lastname@example.org or visit www.multistack.com. For more information from Goex Corp., call (608) 754-3303; e-mail email@example.com; or visit www.goex.com.