11-26-2018 BPU RPT 08 - Laserfiche WebLink

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W A T F R E N E R G Y L RIVERSIDE PUBLIC UTILITIES .�W& Board Memorandum P U B L I C U T I L I T I E S BOARD OF PUBLIC UTILITIES DATE: NOVEMBER 26, 2018 ITEM NO: 8 SUBJECT: PURCHASE ORDER WITH TRANE U.S. INC. FOR INSPECTION AND REPAIR OF AIR INLET CHILLERS AT RIVERSIDE ENERGY RESOURCE CENTER UNITS 1 AND 2, IN THE AMOUNT OF $109,517 ISSUE: Approve the issuance of a purchase order with Trane U.S. Inc., of Davidson, NC, for the inspection and repair of the air inlet chillers at the Riverside Energy Resource Center Units 1 and 2, in the amount of $109,517. RECOMMENDATION: That the Board of Public Utilities approve the issuance of a purchase order with Trane U.S. Inc., of Davidson, NC, for the inspection and repair of the air inlet chillers at the Riverside Energy Resource Center Units 1 and 2, in the amount of $109,517. BACKGROUND: Riverside Public Utilities commissioned Riverside Energy Resource Center (RERC) Units 1 and 2 in June 2006. These fast -start units were strategically located in the city limits and achieve maximum power output in less than ten minutes. RERC Units 1 and 2 are very reliable units that serve a critical role in meeting customer demands during peak periods. Both gas turbine units generate 96 megawatts of electricity and share a 3,500 -ton air inlet chiller system. The chilling system cools the ambient air entering each gas turbine to 47 degrees Fahrenheit. During summer peak months, the colder air represents 20% of the overall electrical output generated from each turbine. Following a recent maintenance activity, staff detected vacuum leaks in the low-pressure section of the chiller system. This section of the chiller cycle operates below atmospheric pressure, and vacuum leaks introduce ambient air into the refrigerant system. The undesirable air contamination is later extracted from the refrigerant system with purge pumps. Operating long term with this condition is not recommended by the original equipment manufacturer, Trane U.S. Inc. (Trane). Staff conducted leak tests on the accessible areas and was unable to locate the source of the leaks. In order to identify and fix the leaks, staff is planning to conduct repairs on the chiller system during a scheduled maintenance interval between planned unit operational periods in February 2019. The leak repair process will be more extensive than the regular unit maintenance process, including disassembling the unit housing and evacuating the refrigerant. Page 55