Marc Garner, Vice President, Secure Power Division, Schneider Electric UK&I
Power efficiency is a critical concern for today’s data centre operators, especially those seeking to meet increasing digital demands, manage energy costs and minimise CO2 emissions.
Maximising efficiency needs close attention to a number of data centre functions, of which power is one of the most important. The type and design configuration of an uninterruptible power supply (UPS), for example, can deliver significant cost savings and lower power consumption for the end user.
Maintaining resilient power to critical applications is the priority for any UPS, yet data centre operators may consider several options to maximise efficiency around the factors of technology, topology, and modularity. Fortunately today, there are many online resources and digital TradeOff tools freely available to help guide electrical contractors, data centre owners and operators, and offer the ability to model scenarios pertinent to their specific requirements.
Some, for example, can help to determine energy usage, efficiency gains and calculate long-term lifecycle benefits, whilst others offer the ability to select and deploy UPS technologies based on uptime and availability requirements, budget and even upgrades to an existing installed base of UPS assets. In this article we’ll explore them further.
Tools to help guide UPS modernisation
Schneider Electric’s TradeOff tools provide data driven insights into a number of different scenarios including traditional data centres, prefabricated and edge architectures. They help end-users to identify basic power, cooling and IT requirements in specific environments, offering key guidance to the user.
In the case of data centre modernization, operators will often have to decide when to replace or upgrade existing products with newer technologies. To help solve this conundrum Schneider Electric has built a Three Phase UPS Modernisation OpEx Calculator, which allows decision makers to estimate their Operational Expenditure (OpEx) and compare the cost of existing installed UPS systems alongside their power consumption.
The tool calculates the cost of maintenance and support contracts, replacement schedules and the estimated remaining life of a system against the power consumption, longevity and replacement costs of upgrading to newer technologies.
Depending on a combination of the key factors inputted, it may be more cost-effective for an operator to retain existing infrastructure in the short term. However, long-term energy usage and replacement parts may impact negatively on both cost and carbon emissions over the lifecycle. Nonetheless, the decision on when and why to upgrade can be more accurately made thanks to this TradeOff tool.
Lithium-Ion and Valve Regulated Lead Acid (VRLA) Cells
Today UPS battery technologies are continually evolving. In the last few years alone, a fundamental technology choice has been between Lithium Ion ( Li-ion) batteries and traditional valve-regulated lead-acid (VRLA) cells. The former offers longer operating lives, greater power densities and smaller physical footprints. They can also withstand many more charge-discharge cycles without degrading performance, which makes them more suitable for deployment in high-availability applications.
The principal disadvantage of Li-Ion batteries remains capital cost, but this is slowly diminishing over time. Studies by Schneider Electric’s Data Centre Science Centre and detailed in White Paper #229: ‘Battery Technology for Data Centres’, found that over a 10-year period, Li-ion delivered a TCO that is between 10% and 40% lower than equivalent UPS systems based on VRLA.
Schneider Electric’s Lithium Ion v VRLA UPS Battery Total Cost Ownership (TCO) calculator allows electrical contractors and other users to model the implications of choosing one technology over the other by setting precise performance attributes such as battery capacity, replacement time or service life, and examining the financial implications of each choice.
Calculating UPS efficiency
A key point to remember about UPS efficiencies is that they vary depending on the load. At low loads, typically below 30% of rated power, the efficiency drops off markedly. This is because a greater proportion of the power delivered is being dissipated by the components, such as transformers, capacitors, logic boards and communication cards. Typically, efficiency of UPS systems increases rapidly between 0 and 30% loads. They start to improve at a more gradual rate after 60% loading, before peaking somewhere above 90%.
Manufacturers will often quote an efficiency rating for a 100% load, but a more accurate picture of the efficiency of a UPS can be obtained from the efficiency curve, which shows exactly how it can vary under power loads. Due to the performance variations UPS systems can carry significant differences in operating costs over time.
One TradeOff tool that helps to address this issue is Schneider Electric’s Three Phase UPS Efficiency Comparison Calculator. It helps users to anticipate the impact of 3PH power systems on energy costs and carbon footprint. The tool allows the user to set the maximum allowable UPS load, along with the desired level of redundancy and the number of systems deployed, comparing the cost and efficiency implications between different models. The calculator also allows the user to estimate the basic energy costs that pertain across different geographical regions and calculate the OpEx that ensues.
Finally, an important element in maximising efficiency is the continuous monitoring and management of data centres and critical infrastructure products. IoT technology and advanced DSP control circuitry are now standardised features in many UPS solutions, allowing them to be monitored and managed remotely from any location.
Status information is continuously routed to a central management console and provides operators with the visibility needed to schedule proactive maintenance and replace products that are nearing their end of life. Artificial Intelligence (AI) and machine learning algorithms identify and alert users to issues, enabling them to respond rapidly before problems arise.
Today intelligent UPS systems and remote monitoring are essential for operators to maximise application uptime and minimise carbon emissions. As technologies continue to improve and become more sustainable, sophisticated remote management software increases resilience and uptime, enabling complex power products to be managed with even greater efficiency, lower operating costs and a reduced carbon footprint.
For more information on Schneider Electric's TradeOff tools please visit - https://www.se.com/uk/en/work/solutions/for-business/data-centers-and-networks/trade-off-tools/