Most data centres incorporate Uninterruptible Power Supplies (UPS) in their electrical distribution circuits. Their primary function is to maintain power to your IT equipment in the event of a mains failure.
About Data Centre UPS Solutions
This may be for only a matter of seconds while the standby generator(s) come on line or, if your site does not have standby generators, the Uninterruptible Power Supply (UPS) may have a longer battery autonomy (run time) to maintain power through short-duration outages. Then, if mains power is still not restored within a reasonable time, a UPS data centre solution will ensure a controlled shut-down of the IT systems. Although a shutdown is often avoided at any cost if your management protocols can accept a shutdown doing so in a controlled manner will enable you to bring your IT systems back on line more quickly and easily once power is restored. Also, shutting down non-critical applications will allow your critical services to stay on for longer – possibly until power is restored, rather than running everything until the batteries run out.
IT equipment also requires a smooth clean power supply. Data centre UPS systems carryout other vital functions such as voltage stabilisation, power factor correction, cleaning and conditioning of the incoming mains power. These functions protect your IT systems from spikes, dips, brown outs and black outs. Exposure to any of these can cause damage to your mission critical data centre hardware.
UPS Sizing and Capacities
UPS duties/capacities are measured in kilo Volt Amps or kVA. This can sometimes cause confusion for data centre mangers as IT equipment power consumption is measured in Watts. Due to the power factor of a UPS these figures may not match. This is because the power factor of UPS’s change from manufacturer to manufacturer.
Systems operate at 0.8pf, 0.9pf or 1pf, also referred to as unity power factor. A 100kVA UPS with a 0.8pf will only deliver 80kW of usable power to your IT systems. A 0.9pf will provide 90kW and a unity unit will provide 100kW. It is very important to understand the power factor of a UPS before making a purchase or specifying a particular make and model.
Most small to medium sized data centres will use multiple UPS’s of around 30 to 300kVA. Having a larger number of smaller units increases resilience and enables capacity to be closely matched to load, improving energy efficiency. Using multiple UPS in your data centre also means you can grow your facility’s power provision in phases. This allows you to match your IT power requirement as it grows giving the benefit of lower initial cost for your data centre.
UPS Energy Efficiency
UPS efficiency has a major impact on data centre energy use. It is important to select a UPS that will be efficient at the actual operating load of your facility and not just its fully rated capacity. With greater focus being placed on data centre energy efficiency many UPS manufacturers are working hard to increase the energy efficiency of their models. New models now provide an array of “eco” modes that deliver efficiencies of up to 99.5%.
Some data centre operators do not operate their UPS system in “eco” mode as the units are not operating in true double conversion, and although small, this does increase the level of risk your IT equipment is exposed to. Most modern UPS now operate at around 96% efficiency in double conversion mode.
Although 3.5% may not appear to be much if you are operating a 1mW (mega Watt) data centre and paying 12 pence per killer Watt hour for electricity it will cost you £36,792 more to provide UPS backed power to your IT systems.
Whether operating in double conversion or “eco” mode UPS efficiencies drop off the less well utilised the unit is. The graphs below show how modern UPS efficiency diminishes as they operate below full capacity. Older units often have much greater losses.
Selection and Topology
Selecting the best UPS system for your application and deploying the correct topology provides an opportunity to significantly reduce running costs and to shrink your carbon footprint.
We work with our clients to understand how their IT load is going to change and grow over time. This means we can design systems that provide the highest level of resilience, flexibility and efficiency and still control initial capital cost.
Understanding your level of required uptime will help us provide a level of redundancy that is suitable for your business needs. Our experienced Electrical Engineers will design and tailor a solution that ensures your data centre achieves the business objectives and goals set for it, whilst still conforming to the most up to date standards and best practices.
As Future-tech is a vendor neutral company we have access and relationships with all the major UPS manufacturers. Below is a list of some of the manufacturers we have worked with over the years.
- Eaton Power Quality
- The UPS Company