Excalibur Energy has modified six
chillers at two Lloyds Bank data
centres. The Liebert chillers
incorporate free cooling and have
Bitzer screw compressors which
operate on R407c. Each chiller has a
capacity of 700kW and provides
chilled water to server rooms.

Pilot installations were undertaken
to two chillers; these were monitored
to establish energy consumption and
cooling load for a period prior to,
and following installation of Liquid
Pressure Amplification (LPA) and EC
condenser fans. Installation of LPA
allows chillers to be recommissioned
for efficient floating head pressure
operation, this increases cooling
capacity and reduces absorbed power
to improve chiller efficiency.

Monitoring demonstrated a 38%
reduction in energy consumption
and benefits in free cooling due to
the performance of the EC fans.

With all six chillers now modified,
the project is expected to reduce
annual energy consumption of the
data centres by 1,500,000kWh, and
carbon emissions by more than 750t.