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o you know exactly how your refrigeration plant is con- trolled? If not, you could be missing out on an opportunity to operate the plant more efficiently. Most refrigeration plants built before the 1980s relied on a thermostat in the return brine line to control the operation of the compressors. While this was a reli- able way to control the compressors, it was not the most efficient system because of the delayed reaction time. This design also requires the brine/glycol pump to run continuously to ensure that the thermostat receives the current brine/glycol temperature. Running the brine/glycol pump this way can cost as much as $500 to $1,000 more per month in energy costs. When using the return brine/glycol thermostat to operate the compressors, any heat that is applied to the ice slab (such as resurfacing) has to pass through the ice, into the rink floor pipes. The heat then must enter the secondary refrigerant (brine/glycol) where it is carried back to the compressor room so that the brine return thermostat can sense the heat load and activate the compressors. This is a long lag time for the compres- sors to react. The ice technician must rec- ognize that the reverse needs to occur once the ice surface is back down to the set operating temperature. Note: The system will not shut down until the brine/glycol has reached a lower temperature than the ice sheet, which may make the compressors run more than required. Technical advancements in the 1980s saw slab sensors become a more reliable way to operate the compressors. When using a slab sensor, the heat put onto the ice surface only has to travel down through the ice where the slab sensor reacts to activate the compressors. This occurs regardless of whether or not the brine/glycol pump is running. Once the RINK REFRIGERATION 101 48 R INK MAGAZ INE march/april 2010 STARrinks.com How TO: part 2 of 6 This year RINK Magazine will discuss refrigeration in an educational 6-part series. This information can be shared with your staff to promote some good discussion and possibly even enhance the ability of your operations staff. We encourage you to share your comments, ideas and repairs related to rink refrigeration systems by sending them along with pictures to davew@starrinks.com. RINK PHOTO Facilities that have multiple controls should operate each independently to determine which runs the system most efficiently. Understanding What Controls Refrigeration Plant Temperature Settings by DAVE WESCOTT D Understanding the controls and making adjustments can save you money.

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