Bedford Data Centre CRAC Unit Replacement
CBRE
Category
Data Centre Energy Efficiency Project of the Year
Entry Description
CBRE installed 10 No. VERTIV Econophase PDX downflow CRAC Units to replace 15 No. Conventional DX downflow CRAC units within the data centre along with 2 No. Displacement DX CRAC units with 2 No. Up-flow DX CRAC units within the UPS room. The recorded saving in the first six months (including during the installation) amounted to $60,000.

About the Client:
A Global Client that has 2 Data Centre’s in the UK. They provide professional services to thousands of clients worldwide, offering services backed up by their own CBRE managed data centres. Data centre space is also operated by CBRE with site resiliency levels for data, power and cooling at N + 1.

The Challenge:
The cooling system for their Bedford data centre consisted of 17 No. conventional DX CRAC downflow units that were at the end of their usable life, inefficient, unreliable & in need of replacement. As the data centre had to continue to operate, CBRE’s challenge was to replace the CRAC units without causing any hot spots or downtime whilst ensuring an N + 1 cooling resiliency throughout the works. What’s more, the client wanted to utilise free cooling to reduce carbon generation and energy usage.
Due to the existing installation, space available and site, the data centre design was limited to a downflow CRAC unit type solution. The additional 2 No. CRAC units replaced were located within the UPS room, where the original down-flow units were not an ideal solution to cool the UPS units within the space they occupied.

The Solution:
The CBRE project team consulted a cooling and installation specialist and together with the client’s design consultant, designed an N + 1 resilient solution that offered the following:
- 10 No. free cooling VERTIV ECONOPHASE DX downflow CRAC units within the data centre (no chilled water is utilised in this free cooling solution)
- 2 No. VERTIV DX displacement CRAC units within the UPS room
All the above units were installed in a carefully planned and phased program over a period of 4 months. Most of the time, only 1 CRAC unit at time could be replaced to ensure the site upheld an N + 1 cooling resiliency.
Replacing the CRAC units was made more challenging due to the arrangement of the external condensing units, meaning only certain units could be replaced in a certain order as a result of the external condensing units needing to operate to maintain the cooling resiliency. At times, the existing units needed to be relocated and reconnected to ensure they were operational as the new units local to area were replaced.
2 No. of the original 17 No. CRAC units located within the data centre were relatively new and were thus retained but left in standby should they be required at any point in the future.
All of the units within the data centre now operate as a team, maintaining a constant under floor temperature and pressure as linked to the fire, BMS and Ekkosense monitoring system.
This solution in partnership with VERTIV and Ekkosense, allows full control of every units as well as critically every rack’s inlet temperature. The 100% DX based free cooling system offers 100% free cooling for at least 8 months of the year, with an additional couple months of the year in part free cooling / part DX mode, with the remaining 2 months of the year, reverting to full DX mode due to external temperatures reaching a point where ambient temperatures do not allow condensing units to condense the refrigerant.
As a result of the Ekkosense system, the CBRE site team were able to simulate the effect of switching individual CRAC units off before the works began, thus allowing the team to ensure the data centre would not suffer any hotspots and maintain the required cooling resiliency.
The 2 No. displacement CRAC units in the UPS room additionally offer reduced energy usage due to their EC fans that operate at 25% of full capacity as a team, with only 1 No. of the 2 No. units' compressors cooling the space at part load, usually 50%, as and when temperatures require.

The Result:
The project was delivered on time, within budget & without any disruptions to service.
An N + 1 cooling resiliency has been maintained, and along with its free cooling system, additional energy savings in EC fans, teamwork and close control of supply temperature and pressure amount to around 45% in energy savings.
Full energy savings have not been realised yet as the completed installation has not reached a full year since final commissioning.
Supporting Documents