Chris Cutler, Business Development Manager at Riello UPS, explores the evolution of ultra-high efficiency modular UPS systems and how technological advances are helping data centre operators reduce their Total Cost of Ownership.
With no end in sight to the seemingly unstoppable rise of Artificial Intelligence (AI), demand for data centre processing power is likely to continue its rapidly upward trajectory. Indeed, various recent analyses from organisations such as the International Energy Agency and consultancy, McKinsey, predict that data centre electricity consumption will likely double in the coming years.
This ongoing trend puts even more pressure on operators – and the wider supply chain including equipment manufacturers – to find potential efficiency improvements and cost savings.
While every UPS manufacturer strives to achieve 100% efficiency, current technology – not to mention the laws of physics – makes that an impossible end goal. However, ongoing advances mean we can now get pretty close.
The latest generation of modular Uninterruptible Power Supplies (UPS) are capable of previously unseen levels of ultra-high efficiency whilst still delivering the robust reliable protection that data centres rely on, all in a more compact, space-saving footprint.
A brief UPS history lesson
In years gone by, most UPS systems were designed and manufactured using a two-level architecture inverter and could typically deliver efficiency of around 96%.
Designs evolved from two to three-level architectures, which needed more components and processing power to control, but helped boost efficiency to 96.5%. While adapting the materials used in filter design enabled UPS manufacturers to push efficiency levels upwards of 97%.
So what comes next? How do we boost efficiency even higher?
The biggest change will likely come in the shift from using traditional silicon-based IGBT components to silicon carbide (SiC) semiconductors. Of course, SiC is nothing new – it’s widely used in the electric car industry which has helped to make the technology more readily available in other sectors.
For UPS manufacturing, silicon carbide components offer several inherent advantages over standard IGBTs, namely:
- Higher efficiency: SiC components exhibit lower electrical resistance, resulting in reduced energy losses, which helps to maximise the overall efficiency of the UPS.
- Increased power density: The technology enables increased power density, making it possible to design more compact and lightweight UPS systems without compromising on power capacity.
- Increased thermal stability: SiC can operate at higher temperatures, translating to a broader operational range and reduced cooling demands.
- Enhanced frequency response: SiC’s faster switching capabilities result in a more responsive UPS system, crucial for handling the rapidly changing load conditions typically found in modern data centres, particularly those dealing specifically with AI applications.
- Durability: The robustness of SiC reduces wear and tear, leading to extended component and UPS lifecycles along with reducing maintenance needs.
Putting theory into practice
Riello UPS’s latest modular offering, Multi Power2, has embraced silicon carbide semiconductors throughout the manufacturing process, including its high-density 67kW power modules.
The result is a modular UPS that delivers a high efficiency of 98.1% in maximum protection online double conversion mode.
Previously, you’d only see such high efficiency if your UPS was running in ‘ECO’ or ‘economy’ mode, where energy savings come at a cost through a subsequent trade-off in reduced protection to the critical load.
Before we move on, it’s important to make a point about UPS efficiency. When stating their efficiency ratings, many UPS manufacturers produce an ‘average efficiency’ figure, which in effect is a combination of the unit’s various operating modes over a period of time.
For example, this period could cover 24 hours split between 12 hours running in online mode followed by 12 hours in ECO mode. For some applications, this is perfectly acceptable, but not for a data centre as at some point you’ll be exposing your infrastructure to higher levels of risk from a power disruption.
Average efficiency ratings don’t offer a true reflection of real-life operating conditions. You could even argue they’re manipulated figures simply to provide customers with artificially inflated values.
However, with these newer SiC-based solutions, there’s no need for such a ‘smoke and mirrors’ approach, as you know the 98.1% figure is in true online mode.
Proof of significant savings
As you’d expect, ultra-high efficiency modular UPS such as Multi Power2 deliver cost, energy and carbon emissions savings when replacing old legacy monolithic UPS systems. But they also significantly outperform the currently available standard modular solutions too.
What follows are two actual TCO calculations provided to data centres in the process of upgrading their UPS. Comparison 1 outlines the savings as a result of replacing a monolithic 1MW N+1 UPS system (made up of 3 x 12 pulse 600kVA 0.9pf UPS) with a 1,250kW Multi Power2.
- Total annual energy cost saving = £95,759.65
- Overall total annual cost saving = £117,544.13
- Total annual CO2 saving = 148.7 tonnes
- Total 15-year cost saving = £2,353,655.21
- Total 15-year CO2 saving = 1702.8 tonnes
While Comparison 2 highlights the savings delivered by a 1,250kW Multi Power2 at 1MW load versus another manufacturer’s latest modular offering, with their system comprising 3 x 400kVA modular units.
- Total annual energy cost saving = £51,099.24
- Overall total annual cost saving = £53,839.91
- Total annual CO2 saving = 79.4 tonnes
- Total 15-year cost saving = £1,078,068.22
- Total 15-year CO2 saving = 908.7 tonnes
In addition to these substantial topline costs and carbon savings, SiC-based UPS offer data centre operators other benefits. In a traditional UPS, capacitors usually need replacing between service life years 5-7, so over a typical 15-year lifespan you might be looking at swapping them out two or potentially three times.
However, the life-long components used in Multi Power2 mean it is realistic to go through the entire product lifespan without replacing the capacitors at all, a significant cost saving plus fewer end-of-life components that require recycling.
All in all, a typical data centre could save around £80,000-£120,000 in maintenance costs over the lifespan of the UPS. This figure doesn’t even consider additional knock-on environmental benefits such as reducing the number of miles engineers will travel because of fewer required maintenance visits.
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