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After leaks were found in the system several years ago, on-going repairs have been required to keep the facility operational. The City suspectsthat a small leak in the polyethylenerink tubing allowed air to enter the refrigeration system. The air then reacted with the calcium chloride forming a corrosive chemical that corroded and degradedthe steel walls of the chiller tubes. An attemptto repair the system was made by plugging several of the chiller tubes that were determined to be leaking. IJn�artu�nately more leaks were found. The City then hired a firm that specialized in testing pressure vessels of this type. Tests were completed last month. The initial testing session found 31 of the 800 chiller tubes had a 70% or greater wall degradation. Follow up testing found leaks in additional tubes. The number of degraded tubes continues to rise with each testing session. Testing was also performed on the shell of the chillertube to determine if the steel wall was corroded, and if so, to what extent. Preliminary results of the testing showed that the vessel wall was not corroded. Since it is likely that the number of degraded tubes will exceed 10%of the chiller capacity, typically regarded as e�ra capacity, the City has determined that the entire vessel shall be re-tubed and a thorough inspection of the vessel shell shall be conducted. As part of the chiller renovation project the City would like to consider improvementsto the refrigeration system that will aid in future maintenance and monitoring of the system. Such improvements should include flanges on each side of the chillervessel, corrosion coupon rack, pressure gauges and other recommended improvements. Access to the chiller vessel is very limited. Tube replacementwill likely require some modification to the building wall and or temporary removal of the existing access window. Once the tubes are removed the interior surface of the chiller vessel shell will be inspected to determin� the condition of the steel shell. Repairs to the existing shell may be required atthat time. So far, tens of thousands of dollars have been spent on attempted repairs to the chiller vessel because of the massive size of the refrigeration system and serviceability constraints. It is essential that the proposed repairs and improvements address monitoring and serviceabilityto aid in preventing future problems of this caliber and to assist with servic��g when required. Design and construction will take place early in 2005. The refrigeration system will not be operational this winter. As part of this project the City would also like to evaluate the feasibility of the following options: � Install one or two plate and frame type chiller systems in place of reconditioning the existing shell and tube condenser type chiller system. The City is interested in the potential redundancy capability and increased system efficiency. ;} Connectthe existing RSVC At�n� to the John Rose Oval's refrigerationsystem, The RSVC arena has a separate direct refrigeration system and floor that has reached its useful life. System efficiencies are typically increased when more than one ice sheet is served from a common refrigeration system. However, in this case, the John Rose Oval's ice surface is much largerthan the RSVC Arena's ice surface creating a large difference in refrigeration demand between the two systems. The challenge would be to serve the RSVC Arena during the summer months when the John Rose Oval is not in operation. Replacing the existing single chiller type system with two smaller plate and frame type Mr. Lonnie Brokke, Director of Parks and Recreation January 26,2005 Page 2 of 7