Walter Meier (Climate UK) has supplied two Hitachi Samurai 400kW chillers to the UK headquarters of Xchanging in the City of London. Specified by consulting engineers Parker Wilson Consulting, the new plant has replaced two older Hitachi chillers to deliver significant savings in energy consumption and carbon emissions.

Xchanging is an international business processing company with interests in insurance, financial service and other sectors. Extensive use of IT in the building results in high internal heat gains so the company requires reliable cooling systems and was also keen to reduce its carbon footprint.

The new Samurai chillers are supplying chilled water to two wings of the building in Leadenhall Street , serving a mixture of variable air volume (VAV) and fan coil systems.

"The continuous capacity control of the Samurai chillers has enabled us to predict chilled water energy consumption savings of over 60,000kWh, equivalent to a saving of over 7,000kg of carbon a year," explained Graham Wilson of Parker Wilson. "This is the result of responding more efficiently to varying cooling demands and being able to make better use of free cooling - enhanced by the introduction of inverter control on the supply air handling plant," he added.

"The inclusion of inverters in the installation allows additional savings to be achieved through finer control of motor speeds in relation to chiller performance. Based on a conservative estimate of the chillers being fully modulated by 15% of their capacity, the Carbon Trust calculates this will deliver a further annual energy saving of 112,002kWh with a further carbon saving of 13,216kg per year.

"We selected Hitachi chillers for their proven reliability and ability to deliver the required performance. Walter Meier's technical support was excellent throughout the project and they were very helpful in assisting with predicted energy savings and emissions reductions," Graham Wilson concluded.

To avoid disruption to staff in the building, removal of the old chillers and installation of the new units by contractor Allen Hubbard Services was scheduled to be completed within a two week timeframe. Thanks to tight scheduling and project management, the work was completed ahead of deadline.