How to dodge data centre meltdowns during a summer heatwave
Mon 30 Jul 2018 | Leo Craig
With the UK basking in baking temperatures usually associated with far-flung holiday destinations, Riello UPS General Manager Leo Craig shares his handy hints to help data centre managers keep their systems cool.
It might seem a little churlish to focus on any downsides to our record-breaking heatwave, but the sizzling summer is just as likely to see IT administrators break out in a sweat for other reasons than the blazing sun.
In our data-driven world dominated by the ‘Internet of Things’ and interconnected devices, prolonged hot spells pose particular problems for both the electricity supply and IT equipment data centres rely on every day.
Why does hot weather cause power supply problems?
This year has been the warmest June ever for parts of the UK (Wales and Northern Ireland) and is in the top five for the country as a whole since Met Office records started in 1910.
Yet while the summer sun and sweltering temperatures are terrific for trips to the beach or barbeques in the back garden, the rising mercury levels place even greater strains on the already struggling National Grid.
Extremely hot weather tends to increase demands on our electricity network, particularly as office air conditioning units are cranked up to keep the nation’s workers cool. Official figures from the Government suggest two-thirds of the country’s offices plus 30% of shops now have energy-intensive air con installed.
Sustained hot spells tend to see an increase in power problems such as sags, where there’s a short dip in voltage, or surges where voltage is higher than the normal mains supply. Sizzling summers even increase the likelihood of damaging power cuts. In the space of a few weeks last July and August, major outages hit Glasgow, Macclesfield, Lichfield, and Sutton Coldfield, to name but a few.
And of course, there have been several high-profile incidents where data centres are plunged into darkness due to heatwave-related power problems, notably telecoms giant O2’s London facility being knocked offline for several hours back in 2010.
Will electrical equipment overheat during high temperatures?
It’s not just the National Grid that’s put to the test by hot summers though. The heat places additional stress onto server rooms, uninterruptible power supplies (UPS), and their batteries.
To state the obvious, such electrical equipment generate their own heat, something that’s exacerbated further when the weather is warm. Air conditioning units have to work much, much harder to keep server rooms cool and equipment from overheating, meaning they’re more prone to malfunction.
Compared to a couple of decades ago, data centre server rooms can be maintained at a slightly wider temperature range (between 16-27°C rather than the previous 20-24°C) without negatively impacting on your equipment’s performance.
In general, a UPS unit will have a maximum recommended operating temperature of around 40°C but depending on the location and the condition it’s kept in, those temperatures can easily top 50°C during the height of summer. Such a scenario should be avoided at all costs, as it will cause premature degradation to components such as fans and capacitors, as well as increase the risk of a serious failure.
However, the main source of heat-related problems in a critical power protection system is the UPS batteries. Now, batteries will typically have either a five or ten-year lifespan, while the sealed lead acid (SLA) versions usually used in a UPS have an optimum operating temperature of between 20-25°C.
In winter, the colder temperatures reduce a battery’s capacity. But during summer, higher than ideal temperatures actually increase a battery’s capacity. Sadly though, such temperatures also have the potential to significantly reduce their lifespan too.
What happens if a UPS battery overheats? As a rule of thumb, every 10°C rise in ambient temperature will halve the overall life expectancy of a UPS battery. That means if the room you store your UPS is 35°C, the batteries will only last for 50% of its lifespan. And if the temperature tops 45°C, your batteries will only achieve a quarter of their expected life.
Such conditions make damaging battery failure far more likely, and the least-worst scenario is that you’ll end up paying to replace the cells far more often than you should. The worst-case scenario for your data centre? Well that doesn’t bear thinking about…
Top tips to keep your IT equipment cool
The good news is there are relatively simple steps you can take to avoid an IT meltdown during hot weather. But first and foremost, the heightened risk of failure during boiling temperatures highlights the importance of building in redundancy to any critical power protection system to mitigate against any potential faults or failures.
In terms of a UPS, where a unit it is located is crucial. An uninterruptible power supply should be installed in a temperature-controlled and well-ventilated room, free of any dust and moisture that could impact on the performance of its components.
Where possible, this area should be in a dedicated server or IT room, but we appreciate this might not be possible for every organisation. In those cases, we’d suggest a little common sense – don’t just hide your UPS out of the way in the basement or a place prone to dampness and flooding. Likewise, avoid placing a UPS in direct sunlight or near any open windows.
Other practical pointers include:
- Don’t put a UPS underneath an air conditioning unit
- Never place heavy objects on top of a UPS
- Always ensure the fans aren’t blocked
- Remember to leave room for batteries and switchgear
- Allow space for maintenance access
- Think about future plans and whether you’ll need space for expansion
The problems posed by sweltering summers also underline the importance of scheduling regular preventive UPS maintenance. While no safeguard will ever be 100% infallible, having experienced and fully-certified service engineers thoroughly checking your UPS and batteries can significantly reduce the risk of anything going wrong as the weather warms up.
Routine maintenance enables components to be proactively replaced and the latest software updates installed, while any potential problems with the UPS can be nipped in the bud before they lead to any unnecessary summer meltdown.
Similarly, remote monitoring services for UPS – such as our cloud-based Riello Connect platform – are an invaluable insurance at times when server rooms face increased stresses and strains. Off-site technical experts act as an extra pair of eyes watching and analysing your system’s key performance data in real-time. Any faults or failures are immediately flagged up and investigated, and field engineers can be swiftly sent to solve more serious issues.
Turning to UPS batteries, and just as a UPS performs best in an air-conditioned room away from direct sunlight, so too do their batteries.
Although not always feasible, storing the batteries in their own separate, temperature-controlled room is the best way to minimise the risk of failure. The UPS itself, plus other IT equipment, could then be located in a different server room running at a higher temperature that’s suitable for them, but would be potentially damaging to the batteries.
We’d recommend a 10mm gap between each block of batteries installed in the racks to ensure adequate ventilation. This also helps avoid something called thermal runaway, an irreversible condition that leads to battery swelling.
And similar to a UPS, regular battery maintenance and testing is absolutely crucial to identify and replace any possibly defective or damaged cells.
How to maintain safe server room temperatures
So we’ve covered how to safely store uninterruptible power supplies and their batteries, but what about your actual IT room?
One of the most common techniques modern data centres employ is using a containment system which mixes hot air generated by the IT equipment with cool breeze from the air conditioning units to maintain the ideal overall temperature.
Even though this method tends to work best in larger facilities with multiple server racks, similar principles can be applied to smaller setups too just by considering the ventilation of the room. There are a couple of things to consider though. Firstly, you’ll need to install blanking panels if there are any unused spaces in your racks. You should also fix air tiles into the cold aisle of your system to make the cooling process more efficient.
As briefly touched upon earlier, keep the server door closed at all times to stop warmer any air being directed into the room. And where possible, only use your IT room for IT equipment. However tempting it might seem if you’re strapped for space, if you use your server room as a storage cupboard to hoard other bits and bobs, it means the air conditioning unit needs to work that much harder to circulate the cold air around.
And we’ve got one final tip for older IT rooms in particular. If you’re still using incandescent lightbulbs, you should upgrade to modern fluorescent lighting. Incandescent bulbs are notoriously inefficient – just 10% of their energy creates light, the remaining 90% generates intense and unnecessary heat.
By following these handy hints, data centre managers can keep their cool and avoid any unnecessary downtime during the current hot spell or any heatwaves to come.