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<br /> <br /> <br />“Page content is subject to Confidentiality Restrictions” <br /> <br />City of Arvada, Colorado | Project #37213 | M&V Report – Year 2 | Page 16 <br /> <br /> <br />City of Arvada, Colorado <br />ECM 6: Boiler Upgrades <br />Savings Unit Guaranteed Verified <br />kWh 27,823 29,288 <br />kW 9 9 <br />Therm 1,451 1,677 <br />Dollars $1,910 $2,087 <br /> <br />Overview of ECM <br /> <br />This measure included replacement of the heating hot water boiler located in the 1991 penthouse mechanical room at <br />the Arvada Center with two (2) new condensing boilers, along with the replacement of the hot water circulation pump <br />and motor with two (2) new pumps to provide lead/lag redundancy. <br /> <br />The existing boiler, flue, and hot water pump were disconnected, removed, and disposed of. The new system installed <br />includes two (2) new condensing boilers, a primary boiler loop with individual boiler circulation pumps, and a secondary <br />boiler loop with lead/lag pumps. The new boilers are BACnet enabled, and the BAS allows for an outdoor air <br />temperature reset schedule to match the hot water supply temperature to the load in real time. A circulator pump was <br />installed for each new boiler, paralleled together on the prima ry loop. A new hydraulic separator with integral air and <br />dirt separator was installed. The expansion tank was replaced with a new unit. The flue that was removed was replaced <br />with new boiler direct venting, including roof flashing. <br /> <br />Two (2) new heating hot water pumps were installed on the secondary loop to replace the existing hot water pump that <br />was removed. The pumps are sequenced in a lead/lag function by the BAS. VFDs were installed on both pumps, and <br />the speed command is provided by the BAS. <br /> <br />Insulation was installed on all new piping, as well as existing un-insulated hot water components that remain in service. <br /> <br />During project development, a bin weather data spreadsheet calculation was utilized to determine the baseline and <br />proposed energy consumption associated with heating the spaces. First, the existing boiler efficiency and loop pump kW <br />were applied to the heating load that was calculated by the bin weather data calculation to determine the existing <br />energy consumption. Next, the proposed boiler efficiency curve, loop pump kW, and loop pump speed curve were <br />applied to the heating load that was calculated by the bin weather data calculation to determine the proposed energy <br />consumption. The difference between the proposed and existing energy consumption results in the savings. <br /> <br /> <br />Commissioning <br />After the installation of the ECM, commissioning activities were performed in accordance with Schedule Q of the EPC. <br /> <br />In order to verify proper installation during construction, Ameresco measured combustion efficiency, performed water <br />side flow balancing, performed a point-to-point check, and verified that all sequences of operation are in accordance <br />with the design. <br /> <br />The commissioning process for this ECM included performance testing of boiler operation, primary and secondary pump <br />operation, outside air reset operation, and safety operation. Also verified were schedules, setpoints, sequences, <br />lockouts, alarms, interlocks, and control strategies. A full pre functional test was completed on January 27 th, 2021 that <br />verified all nameplate data, proper installation, and proper operation.