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The original refrigeration systein was installed with the construction of the building in 1969. It was renovated and converted to a direct system by �Iolmsten Rink Master System in 1979-I980. Hotmsten Rink Master Systeni dominated the ice rink market during the 1970's and 1980's. The system is served by four (4) Yark G63SA compressors and one (1) Yark Y Series compressar. Each compressar is 50 hp and approximately 27 tons. The total capacity of this system is agproxiinatefy 163 tons, mare than adequate to serve one ice sheet. Parts far the 36 year old compressars are still available but are expensive. The arena staPf operates the system with a 150 to 160 psi head pressure rather than mare standard 180 to 200 psi head pressures. This lowers the condensing temperature from 100 degree F to approximately 85 degree F increasing the system's capacity by approximately 13% or 20 tons. This lowers the harsepower by approximately 10% increasing the overall efficiency of the compressars. The downside of this operating procedure will likely require longer runtimes on the condenser fan and water pump, additional chemicals to treat the condenser water, lower the amount of waste heat available for recovery, and lower the pressure of the refrigerant supplied to the rink floar. The suction pressure on the compressars is maintained around 37 to 40 psi which is right at the design suction temperature o f i 5 to 18 de�rees F. The majority of the remaining components ofthe refrigeration system fi.c_ low pressure receiver, pumper drums, and waste heat system) is over 25 years old and has reached their expected life. The system is in need of repair or replacement in arder to serve the facility reliably, safety and at its full capacity. There are two main options far improving the existing refrigeration system. They are: Replace the existing refrigeration system with an indirect refrigeration system. In this case the ice rink floor would also have to be replaced. Indirect refrigeration systems are typically 20% to 30% less efficient than an dircct systems. However, with the phase out of R-22 in the not-so-distance future, indirect systems with alternative, less effici��at refrigerants such as R-507 have gained popularity. R-22 refrigerant, a hydro chlarofluarocarbons (NCFCs), is scheduled far phase out in new equipment in the United States in 2010 and in renovated refrigeration systems in 2015. Currently there is no drop-in substitute far R-22 refrigerant but with the extensive use of this refrigerant supplies will likely be around far beyond the phase out dates. 2. Repair the existing direct refrigeration system. With Che recommended repairs discussed in the following paragraphs and if the primary low pressure receiver vessel is found to bc in good shape, there is tto reason why a renovated system shouldn't last another 15 to 20+ years with continued proper maintenance. The following repairs are recommended to extend the life of the existing refrigeration system. A. Replace the insulation on the chiller vessel. This item was placed as the number one priarity mainly because it is a safety issue. The vessel has corroded al�ong almost the entire bottom as is evident with the staining of the insulation. This is a common problem with chiller vessels on Holmsten packaged refrigeration systems. The extent of the corrosion can not be determined without removing the insulation. The recommended repair includes removing the existing insulation, conducting a visual inspection ofthe vessel, conducting ultrasound testing in specific locations on the vessel to determine the wall thickness, sanding the surface of the vessel, prime, paint and re- insulate the vessel with 2" of polystyrene insulation and jacketing. Access panels could be designed into the insulation far periodic inspection of the vessel's surface. We 15