A major challenge to Robert Brinck, Port Engineer and Head of Operations at Caesar’s Casino in Elizabeth, Indiana, has been the riverboat’s source of condenser water, which is pulled straight out of the Ohio River.
Typical condenser approach temperatures on one of the four 450TR chillers, fully loaded, would be about two to three degrees with fairly clean tubes. Using the Trane Summit control system, Caesars has been able to monitor the condenser approach and, unfortunately, has had to shut down the chillers frequently to clean the tubes when the approach gets up to six or seven degrees.
Depending on the load, water temperatures and the mud or debris in the river, the frequency of the high approach temperatures would vary. In the summer months all four chillers are needed for comfort cooling on the boat, but summer is also when the river is the hottest and dirtiest. Caesars would typically have to shut a chiller down about once a month to brush the tubes just to keep the chillers from tripping on high head pressure.
If Caesars lost one chiller during this critical time, they would have to start shutting down some of the decks. This would help decrease the load on the remaining chillers, but it would mean thousands in lost revenue for the casino.
John Faith, with Harshaw Trane in Louisville, has managed the Caesars account since the riverboat casino opened. The first time the condenser heads were opened, it became obvious to him that a solution had to be found for the build-up of mud and debris in the condensers. “The bottom rows of tubes were completely plugged in some of them,” he says.
Faith noticed the Automatic Tube Brushing (ATB) System at a trade show in 2001 but wanted to be absolutely sure that any solution provided would be reliable in the long-term. He investigated different installations of the ATB System and learned that end-users were very pleased with a system made by Water Technology of Pensacola, Inc.
How it Works
The ATB System cleans the chiller condenser tubes while the chiller remains on-line. This is accomplished by back flushing the water several times each day. During the back-flushing period, which lasts about thirty seconds, small nylon-bristled brushes shuttle through the tubes and wipe the tube walls. When they are not moving through tubes, the brushes rest in open-ended catch-baskets that are permanently installed in the tubes.
Usually, the valve cycles every six hours to eliminate tube fouling and scale. At Caesars, Water Technology set the 24-hour timer to cycle every three hours to ensure that mud and debris do not have a chance to accumulate in the tubes and brushes.
“A key point that became evident very quickly,” Faith says, “was in the manufacture of the 4-way reversing valve, which is the key to the system’s success.” The Water Technology valve has stainless-steel internal parts that seat against hard rubber.
Faith recommended the ATB System to Robert Brinck, who quickly had it in the budget. In May 2003, Water Technology performed a complete turnkey installation.
In June, a one-month follow-up visit to Caesars showed that the Automatic Tube Brushing System had not only performed as promised but had actually improved the chiller performance. At 75% load, one chiller was showing less than half a degree approach temperature. The other chillers were operating at less than two degrees approach.
At the end of July, all four chillers were running at full load. Usually, by this time the chiller operators would have already had to clean the condenser tubes manually because the approach temperatures would have been excessive. With the ATB System installed, approach temperatures on all four units were less than two degrees, which indicates very clean tubes.
In November, another follow-up showed that all four chillers were still operating at less than two degrees on the approach temperatures.
With this kind of efficiency, it is expected that the total installed system cost of all four systems, which was less than $100,000, will be returned to the casino easily within a two-year period.
Long-term satisfaction at other sites that have the ATB System, including 3M, Lockheed, Intel, Motorola and NASA, indicate that the initial results experienced at Caesars will carry over for many years to come.