Keeping Cool Over Bitcoin
Against the background of recent news that Crypto-currency computing is swallowing-up more energy than the populations of Iceland, Ireland and most African countries, we asked Alan Beresford, MD and CTO of EcoCooling, to share what he’s learned over the last two years working closely with the owners and operators of a new breed of data centres – ‘The Crypto Miners’.
You’ve probably heard of Bitcoin, the first and most famous Crypto-currency. If not for its underlying Blockchain technology, then you can’t have missed reporting of the Bitcoin currency’s incredible volatility.
What you may not have heard of, however, is Ethereum, the No 2 Crypto-currency and, would you believe there are now around 1380 other crypto-currencies? All are based on variants of the blockchain cryptographic distributed ledger system owned by no-one (as opposed to the central ledger approach used and owned by the banks).
In simplistic terms the transaction ledger – I’ll use Bitcoin as my example – is distributed across hundreds of thousands of computers called ‘miners’. Every transaction has to be validated and recorded on every instance of the ledger across all of these mining computers. This, together with the cryptography involved to keep everything secret and secure, results in an absolutely massive computing load!
In fact, the global energy consumption is estimated to be 29TWh (terawatt hours) in the last year! That figure would equate to an equivalent constant load of 3GW (gigawatts) running 24x7x365!
As an aside, because no entity owns or controls either the ledger or all the computers that crunch the data, the inventors came up with the idea that each of the 21 million possible Bitcoins would have to be ‘mined’ - albeit from ‘the Ether’ rather than being dug from the ground. Every so often, one of the owners of the hundreds of thousands of computers busy ‘mining’ will be awarded a Bitcoin – which is then said to have been ‘mined’. Just before Christmas 2017 one Bitcoin would have been worth $20,000 US. At the time of writing that’s fallen to $10,000 - but that’s still well worth running computers and paying the electricity bill!
From bedroom to data centre
Crypto-currency was devised to be ‘of the people’ and so many miners started out with a computer in their bedroom or garage.
But these are not standard PCs or even standard Windows/UNIX servers. Most either use ASIC (application specific integrated circuit) processors or the GPUs (graphics processing units) that were originally designed for gaming consoles and graphic cards. Indeed, as a result of the rise in crypto-mining there is now a world shortage of GPU chips for gaming consoles! So, even the smallest mining computer is a high capacity, energy-hungry unit.
Many home-miners have moved from working solus (with a very low probability of a very high reward) and have instead joined ‘mining pools’ where all of the miners in the pool share out the ‘wins’ from mining. The result is that they all make lower but regular income in proportion to the processing power they supply to the mining pool.
And the outcome of that has been that people have rapidly grown from one or two ‘miners’ to grabbing hold of unused warehouse and agricultural buildings to put together ‘mining data centres’ with hundreds or thousands of mining computers. But these are often unlike any of the data centres you would recognise.
For example, in some of these data centres you will see conventional 19-inch racking, but in many there will be mining computers by the thousand on what is effectively warehouse shelving. And whereas we would normally expect a two-year lead time from design to ‘in-service’ for a conventional data centre, many of the projects we’ve been involved in have deployed 2MW or even 4MW of computer power in 16 weeks start to finish!
That’s not to say all mining data centres are that basic. We’ve worked with a number of data centres, particularly in the Nordics, who have built to
low-tier data centre standards – but even they have had to be able to move in the 16 week get-ready timeframe demanded by the crypto-mining community.
Until recently, something like 80-85% of crypto-mining had been undertaken in China. But the World is changing. The combination of the Chinese authorities perceived opposition to Crypto-currencies, plus rising Chinese electricity prices, means that the West is becoming a more attractive location for miners.
Many of the western world’s larger crypto-mining facilities are in the Northern regions where there is cheap hydro power available. But crypto mining is happening everywhere, including throughout Europe and in the UK.
So, getting back to what we at EcoCooling have learnt over the last two years working in the sector:
- The requirements are very different to conventional data centres. Some Crypto facilities are small – as little as 3kW load. Other Crypto facilities are massive and rack densities are crazy – up to 100kW a rack is now being proposed. This has given rise to a very different set of design criteria
- Low total cost of ownership (TCO) is essential to all miners. Whatever money the miners invest they want to go into the mining computers that make them money. The very minimum is to be spent on the ancillary stuff! The key KPI these guys use to control their facilities is the total cost per kW of mining power rather than PUE or other conventional measures.
- Until recently, many mining operators concentrated on lowest capital cost rather than adherence to ASHRAE recommendations. They discovered that this caused reliability problems and realised that a broken mining computer is not making any money!
Whilst absolute adherence to ASHRAE standards is not necessarily a good strategy for mining data centres, they now realise that it is essential to follow the principles of stable temperatures and filtration to maximise equipment reliability and hence availability. As a result, intelligent fresh air ventilation schemes are becoming the routine solution.
- Because of the deployment timescales required, the cooling system, like the mining computers, absolutely has to be plug-and-play. This also significantly reduces both labour cost and installation time.
- The cooling system has to be effectively maintenance-free for extended periods – because often these mining data centres are far from civilisation and expensive to get engineers to.
- Modularity is key. For a lot of the smaller miners they only need one or two x 15kW of cooling and it needs to be ‘plug-in, switch on, forget!’ However, the same is true at the hyper-scale too.
- Rapid scalability is also essential. The larger crypto data centres need to get rid of 100 kW of heat per linear metre of servers!
We rapidly discovered, when we started to model the proportion of time our coolers would be in ‘evaporative-cooling’ mode, compared to ‘pure-ventilation’ or ‘free-cooling’ mode, was low to zero in the Nordics. And once customers realised that by deploying our ventilation-only products (leaving out the evaporation unit) but, and this is essential, retaining all the intelligent air-mixing they could save a lot of CapEx. Also this drops the PUE to less than 1.05 meaning that that energy required for cooling falls to less than 5% of the compute load.
The low energy use has two benefits – firstly low operating cost and secondly lower power infrastructure capital cost. A massive boost for total cost of ownership. And, of course, reduced complexity means shorter installation times and reduced maintenance.
The cooling strategy for Crypto facilities is dependent upon the type of equipment and its location. Many of the hyper-scale mining facilities are being built in the cold northern territories. In response to this, EcoCooling developed an arctic-grade fresh air cooler which requires no supplementary cooling at all for these climates.
It is only when crypto facilities are located further south that evaporative cooling will be needed. This normally eliminates any requirement for costly and complex refrigeration equipment.
One of the great benefits of being the CTO and Chief Designer at EcoCooling was that, in the early days of our journey into crypto-cooling, I could re-design our products (in concept at least) on the plane back from meeting these fascinating and highly-driven new customers!
Of course after a while designs stabilised, and we’ve ended up with a completely modular plug-and-play solution-set that can scale from15 kW to multi-megawatts of cooling in pure ’free’ ventilation, plus an equivalent modular set of combination ‘free-plus-evaporative’ cooling modules that is totally aligned to the needs of the Crypto sector.
Almost accidentally, we now have a suite of ventilation-only products that can be deployed in not only crypto but also some conventional data centres in Europe, UK and other temperate climates!
To summarise, the crypto data centre sector is very different to the conventional data centre market.
Very low TCO is key, with miners aiming to build their data centres at less than £500k per MW compared to the ‘norm’ of £2m to £10m per MW.
Plug-and-play modular solutions have proved to be the answer to the need for rapid deployment - and we’ve found that, by developing remote-commissioning and remote-support, we have reduced the installation to a low-skill process easy for local labour to undertake. For example, a 200kW module including cooling, containment, racks and power distribution can now be installed by 2 people in less than 3 hours!
Reliability is also key, but balanced by the low TCO requirement, leads to a requirement for cooling solutions that are low energy, highly efficient, low maintenance and with a low infrastructure imprint.
We’ve discovered that intelligent direct ventilation (with high efficiency EC fans) provides the majority of the solution-set but that the intelligence aspect is absolutely critical to delivering the miner reliability levels required. Being able to augment this with low-TCO evaporative cooling completes the required product set.
The disruptive technology of crypto-currency has led to a “gale of creative destruction” in the approach to building data centres. Conversations regarding data centre construction are very different now!
This new approach will probably form the foundation to support the stratospheric growth in processing demands from the emerging technologies of blockchain, artificial intelligence, virtual reality and augmented reality. This is the future!