Our friend electricity
20-08-2012 - John Hatcher
At Borri we believe that the electrical layer presents the greatest opportunity to further increase the efficiency of all data centres and are working with the industry to reduce energy costs. However, it is also crucial that operators choose UPS solutions that can not only provide high efficiency levels but also provide reliable back-up power.
UPS systems form the foundation of a data centre’s electrical infrastructure and provide physical ‘insurance policies’, protecting the safe operation of the computing layer. It is therefore vital that operators are not blinded by the drive for greater efficiency and remember the primary purpose of the UPS system – ultimate power protection.
A conventional UPS solution, operating in true online double conversion mode (VFI) will provide the highest level of protection. However, historically this type of configuration will achieve a poor level of efficiency especially when sized conservatively for a data centre application.
The efficiency figures can take a further drop when multiple UPS units are used in parallel for resilience and redundancy, taking the maximum loading to 50 percent of total capacity.
For many years now UPS systems have included an ECO option, or a direct line mode of operation (typically VI or VFD), this bypasses the online double conversion technology and allows power to directly flow from input to output. This configuration significantly increases efficiency levels but also cuts the protective nature of the UPS.
Where once this function was used for non-sensitive loads such as emergency lighting systems which are not really affected by a short power break, misguidedly, some data centres are now using the ECO mode as a standard setting, to save power.
Some UPS manufacturers to increase their products efficiency are even now employing these ECO modes as the standard operation. Part of this is now possible due to recent developments in technology. This has resulted in the increased intelligence of UPS solutions, enabling them to automatically select which mode of operation to choose, subject to mains voltage conditions, historical data, and even the weather. A minority of UPS manufacturers have taken this further and removed the ability of data centre managers to manually change the settings in preparation for even a planned power cut!
These new technologies can now achieve efficiency levels of 95 to 98 percent. This is a substantial increase when compared to conventional online double conversion UPS, but it is subject to a very significant compromise in protection, as the UPS becomes a reactionary device and puts the data centre at risk.
Any modern UPS which operates as a default in this way (VI or VFD) of operation has to react to any issue with the mains supply, it may well react within a few milliseconds, but those few milliseconds can easily compromise the safe operation of the computing layer supported by the UPS, the very reason the original investment in the UPS was made.
Conventional online double conversion UPS solutions are unable to achieve the same efficiency levels, but they do provide a constant output to the load that is isolated from mains input protecting the connected equipment from all mains borne disturbances, and therefore delivers far superior power protection.
However, at Borri we believe that data centre managers should not have to choose between high efficiency with compromised protection, or complete protection with compromised efficiency and after extensive research and development, have developed a portfolio of UPS systems that provide the best of both worlds. Available from 60kVA upwards, the UPS units are of traditional design and incorporate online double conversion topology. They also include an output isolation transformer as standard to provide ultimate protection, due to galvanic isolation of the critical load from input spikes, surges, inverter switching devices and DC voltages.
Investing at component level ensures that users gain maximum power protection by operating in online double conversion mode but can also achieve high efficiency levels. These sophisticated UPS solutions from Borri can operate at efficiencies of 95 percent at full load, and even over 93 percent at half load and below, ensuring users deploying the units in redundancy can still achieve impressive efficiency gains.
Not content with this, the latest FXS upgrade in 2011, has added the option for Smart Online (SOL) mode, giving control to the user and the option to allow the UPS to switch between conditioned line and direct line mode of operation.
Most importantly, data centre operators can take full control. Consideration can now be given to the power output, day-to-day energy consumption and environmental impact, as the FXS upgrade gives data centre operators the flexibility as to whether they operate in Online Double Conversion (VFI) for complete protection or run Smart Online Mode for even higher efficiency. The flexibility of the system allows for this decision to be constantly reviewed and changed as required by the data centre.