Data centre cooling: EC upgrade pays off for UBS


23 November 2017
Daniel O’Connell, Business Development Manager Upgrade with ebm-papst, explains how the leading fans and motors manufacturer collaborated with Vertiv and CBRE to review energy efficiency at three of global financial services company UBS’s London data centres.
The simplest way to reduce the energy consumption in buildings is to ensure that all heating, ventilation and air conditioning (HVAC) equipment is fitted with the highest efficiency EC fans. Those involved in the data centre industry are quickly realising the energy reduction potential in their buildings through upgrading HVAC equipment to innovative Electronically Commutated (EC) fans.  The motor and control technology in GreenTech EC fans from ebm-papst has enabled UBS to benefit from proven efficient upgrades to its data centre cooling systems.
ebm-papst undertook an initial site survey to review the types of units being used and the potential solutions that were needed; along with an estimation of the payback period for any new kit. The units that were in place before the project were chilled water, with an optional switch to lower performance and utilised AC fan technology. In order to improve efficiency, ebm-papst recommended upgrading the equipment with EC fan technology.  Based on the survey results, a trial was then agreed on a single 10UC and 14UC CRAC unit to establish actual performance and energy savings. Data was logged before the upgrade and again once the trial units were converted from AC to EC.

Post upgrade trial data revealed that less power was absorbed by ebm-papst’s EC fan motors than by their AC predecessors. Based on this information, UBS decided to proceed with the conversion of all units, installing 191 fans within 76 CRAC units. Three different unit models were installed: 39x14UC units; 21x10UC units and 16xCCD900CW.

Vertiv then worked with CBRE (who project managed the upgrade) both to UBS’s satisfaction and without causing disruption to the live data.  The main element of the upgrade project was the replacement of all fans, with ebm-papst’s EC technology direct drive centrifugal fans, including the installation of EC fans within a floor void that required modification.

Since completion of the project, the following savings have been made:
  • Energy saving – 10,657 MWh
  • Financial saving - £667,836 after payback of total install costs
  • CO saving – 5,229 tonnes
On average, UBS has seen a 48% energy saving across all units and a payback period of under two years. Other project paybacks include a CO reduction of 5,229 tonnes.  In addition to these savings, new control strategy software was put in place; which controls the EC fans on supply air temperature. This saw a further reduction of 14% in energy usage. UBS’s data centres are now also benefitting from reduced noise levels, increased cooling capacity and extended fan and unit life.

Project challenges
UBS operates a 130,000 sq ft data centre in west London, which is fundamental to the operation of the firm’s global banking systems. Within this site there were a number of Down Flow Units (DFUs) operating around the clock, making them crucial to sustaining the required operating conditions for the computer equipment in the data centre.  The challenge was to improve the energy efficiency of the data centre, freeing up additional electrical capacity to use on IT resource. In addition, the task was to improve the airflow and improve controllability of the cooling units in the data hall.  

Project restrictions were extensive given the live data environment and the upgrade teams were only allowed access to three halls, with only one unit switched off at any one time. However the upgrade was delivered on time and to budget, without disruption.  Work took place while the data centres were live; the project managers had to factor in working space and access around constraints from existing equipment and infrastructure.

ebm-papst replaced the existing DFUs in the data centre with high efficiency direct drive EC fans in the Computer Room Air Conditioning (CRAC) units. UBS’s objective for the project was to reduce the drawn-down power by up to 30%, resulting in a 180kW power reduction load to be allocated to IT equipment.

The solution resulted in a load reduction of 250 kW. This resulted in an annual power saving of 48%, which allowed UBS to increase IT power consumption in addition to reducing CO emissions and energy costs. Nearly five years since the project took place, UBS has seen the below key metrics:
  • 191 fans installed
  • 76 CRAC units
  • Three different models installed
  • Energy saving -10,657MWh (4 years and 10 months)
  • Financial Saving - £667,836 after payback of total install costs (payback period of 23 months)
  • CO Saving - 5,229 tonnes

The energy savings from the EC fan replacement project were exactly as predicted and there was no need to perform any additional analysis due to monthly energy reports being dramatically lower. The EC fans have continued to deliver energy savings, through increased reliability, resulting in a reduced maintenance burden for CBRE and UBS.

HVAC systems can be responsible for over half the energy consumed by data centres. In cases where energy is limited, improving the energy efficiency of HVAC equipment will result in an improved allocation of energy resource to IT equipment. Whilst many new data centre facilities built in the UK already incorporate EC fans in their HVAC systems, many older buildings continue to use inefficient equipment. Rather than spending capital on buying new equipment, often the more cost-effective option is to upgrade the fans in existing equipment to new, high efficiency EC fans.

With ebm-papst GreenTech EC fans, the impeller, motor and electronics form a compact unit that is far superior to conventional AC solutions. The UBS project is an excellent example of how upgrading from AC to EC technology can impact on energy savings, carbon and CO reduction.
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