The project used new Carrier chillers which replaced three old centrifugal chillers and two reciprocating chillers with a combined capacity of 4.2MW. The new chillers are very efficient variable sppeed chillers with a capacity of 5.8MW. In spite of the increased demand on the chillers, the Bank of England will save thousands a week thanks to the new chillers, as well as redcutions in carbin emissions and other running costs.
AECOM provided the specification for the chiller project and Interserve Engineering Services was the main contractor. Carrier won the contract to supply four chillers because of their ability to meet the deadlines, effiency and engineering requirements. One of the chillers was Carrier's AquaEdge™ 23XRV water-cooled screw chiller which includes a variable screw drive and hermetic motors. Carrier had to ship it from the USA becuase, at the time, it was only made there.
The project used two water-cooled Carrier AquaForce® 30XW chillers which used twin rotor compressors. which provide extra cooling to top up the base-cooling. A smaller chiller, the Carrier AquaForce® 30XW1052 is the main chiller during the winter.
"Work on the progressive project had to be carefully managed over the 24-month changeover period to ensure continuity of cooling throughout. Due to its scale and importance for the Bank’s operations, it was a major undertaking requiring a high degree of planning collaboration and close working between all the parties."
"The underground plant room is a bit like a ship's hold," says Robert Foster. "There is a hydraulic lift for access, but the space is restricted and difficult to operate in, particularly given the size of the equipment requiring removal and replacement."