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most economical price. The flexibility of a control like this is almost endless and the ability for <br />remote monitoring and control provide a robust control for the entire refrigeration plant that <br />can be uniquely programmed to maximize efficiency of the ice system at the Oval. A control like <br />this should provide 15 to 20 years of service. <br /> <br />Flooded Chiller <br />The flooded chiller and attached surge drum, manufactured by Vilter Refrigeration, is also <br />original, with the exception of the internal chiller tubes which were replaced in 2005 due to <br />excessive corrosion. The fiberglass insulation, covering the chiller vessel and surge drum, was <br />also replaced in 2005 due to excessive exterior vessel corrosion caused by moisture that was <br />trapped in the insulation. The insulation was replaced with a less water-absorptive urethane <br />insulation that appears to have resolved the corrosion issue. <br /> <br />While the flooded chiller is 25 years old, it was re-tubed in 2005 and depending on the condition <br />of the tubes and the insides of the vessel could operate for another 10-15 years of service. We <br />recommend that the vessel be opened, and the tube condition be verified prior to proceeding <br />with any improvements to the refrigeration plant. <br /> <br />If the tubes are found to be in poor condition, then several reasonable options are available <br />moving forward. Simply re-tubing the vessel in place, as was done in 2005, could be one <br />approach. A re-tubed chiller could result in another 15-20 years of service. The cost of re-tubing <br />a chiller vessel, however, could approach the cost of purchasing an entirely new chiller vessel. <br />The challenges with bringing in a new chiller vessel are significant. Removing the existing vessel <br />is not that difficult for it can be cut apart into smaller pieces and hauled out the existing double <br />pedestrian doors of the refrigeration room. More complex and expensive is bringing in a new <br />vessel, requiring either partial roof removal or removing the end wall to accommodate <br />placement of the large vessel into the room. <br /> <br />Another option, possibly an energy savings idea, would be to use a flat plate heat exchanger and <br />surge drum in lieu of a traditional shell-in-tube chiller, reducing the size of equipment that <br />needs to be placed in the room to a fraction of what it currently exists. A flat plate heat <br />exchanger would best operate with an ethylene glycol brine rather than the calcium-chloride <br />brine currently being used, with a reduced potential for fouling. Determining the feasibility of <br />this type of installation is not within the scope of this report but there could be many benefits. A <br />few include: 1) equipment could be brought into the refrigeration room through the existing <br />double pedestrian doors; 2) a significantly reduced ammonia charge; 3) elimination of the <br />complexities related to stabilizing the calcium chloride brine; and 4) possible energy efficiencies <br />greater than the existing system. A flat plate heat exchanger would be more efficient than the <br />current shell and tube condenser and a fraction of its size making installation much easier. The <br />less efficient ethylene glycol brine would impact the overall efficiency of the design, so this <br />would need to be weighed against the efficiencies of the flat plate heat exchanger to see how <br />the net overall efficiency compares to the existing system. There are many operational <br />121212 <br /> <br />