But what do you do when the retrofit involves a 600-ton condensing unit that provides cooling for a large manufacturing facility? You turn to a temporary condensing unit trucked to the site.

Officials at PPG, a manufacturer of coatings, sealants, adhesives, and fiberglass, decided to retrofit a system at a West Virginia facility from R-12 to R-134a. The company's condensing unit, which operates at –10°F, is used as part of the process that produces chlorine for industrial and commercial use.

Company officials called on NuTemp Chicago's Industrial Engineering Group to design and build a temporary 1,000-hp condensing unit. The designing and fabricating took four months while field workers prepared the site for installation.

It took two weeks to install and start up the unit. The plant's existing evaporator was kept on line, so the temporary condensing was installed in parallel with the existing system and run simultaneously for a week. Then full capacity was shifted to the temporary unit.

The temporary condenser was required to operate independently, although it was completely intertwined with the permanent system. According to NuTemp officials, "Specific functions of the permanent equipment and certain site requirements meant that a very special design had to be implemented in order for the two systems to work together. The equipment ran on 2,200V site power, and used cold river water during winter operations of condenser cooling, operated 24 hours a day, and held loads between 0 and 100 percent."

Officials noted a challenge of running two condensing units using the same evaporator. Further, they said, the temporary unit had to run from a remote location while still managing system oil and refrigerant. Both challenges were met by a microprocessor control located on the temporary condensing unit's skid.

The temporary setup operated for two months while the refrigerant changeover was made. Representatives of the manufacturing facility said production was normal.

NuTemp's application engineer, Fred Landis, said, "NuTemp isn't your typical rental chiller company. We not only provide standard equipment for nominal commercial and industrial applications, but we take pride in having the ability to offer custom industrial solutions."

For information, contact www.nutemp.com.

Publication date: 04/05/2004