A contractor welds the liquid return line that allows the NICL freezer to be cooled by either one of the two new evaporative condenser units.
—Credit: Geoff Hargreaves/NICL
On October 20, 2011 the NICL refrigeration system was officially cooled using the new backup evaporative condenser unit (ECU-2). Once it was determined ECU-2 worked well, the process of removing the original (circa 1993) ECU began. The NICL refrigeration system ran on ECU-2 for several weeks while the primary cooling tower, ECU-1, was replaced. November 3, 2011 was a very big day in NICL history. ECU-1 was brought online and, for the first time in NICL's history, the NICL refrigeration system had two new functioning evaporative condensers! Because the passivation process was not yet completed on ECU-2, the system was switched back to operate on ECU-2.
On November 28 it was determined that the passivation for ECU-2 was still not complete; the consensus among the key parties was that the chemical passivation process should continue for another two weeks. On December 12 the passivation of ECU-2 will be complete and we will bring ECU-1 on-line as the primary cooling tower. From then on, ECU-1 will run most of the time; ECU-2 will be exercised on regular basis to ensure all is working well. If there is a problem with ECU-1, ECU-2 can be brought on-line with minimal effort. The switch from ECU-1 to ECU-2 can occur in 30-45 minutes once the refrigeration contractor is on site.
By December 31, 2011 the NICL refrigeration system will be operating with redundant evaporative condensers. Thanks to all who were a part of this process. The NICL could not have completed this major accomplishment had it not been for the National Science Foundation funding, input, insight, and encouragement.