'Digital boilers' – Emission-cutting gamechanger or just hot air?
Jim Drury

A UK firm insists its closed-loop system that uses heat generated by computers to warm buildings is a low-cost way to help save the planet – and cut energy bills.

Since building a small data center at a leisure center in Devon, tech startup Deep Green has been inundated with requests from similar businesses seeking to reduce their bills in the midst of the ongoing global energy crisis.

As governments struggle to meet net-zero targets to reduce climate emissions, the firm says its digital boiler system could cut up to a fifth of current emissions.

The system works by placing small data centers in the plant rooms of public buildings and using the energy generated to the heating system via pipes.

At the Exmouth Leisure Center, a 28kW system that runs a high-performance computing (HPC) cluster has been fitted inside a plant room close to the swimming pool. The heat generated from the computers is used to warm the pool, while the transfer of heat to the water cools the computers.

Deep Green chief executive Mark Bjornsgaard says data centers account for 3 percent of global emissions and their owners spend around half their running costs on cooling their machines. He says cutting both in one stroke could be the ultimate win-win scenario.

Data centers have traditionally been vast, often remote, buildings, with the millions of computers hosted in them generating huge amounts of heat. With processing needs forecast to rise tenfold in the coming decades, their carbon footprint could spread exponentially, making it even more difficult for governments to cut carbon emissions.


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"Computers are incredibly efficient at turning electricity into heat," Bjornsgaard tells CGTN Europe. "We've got 3 percent of the world's electricity supply literally heating up the atmosphere more because it's just ejected into the atmosphere. If you're serious about net zero, then our solution is brilliant.

"The really clever bit is that 50 percent of the OpEx (operating expenses) of a data center is spent cooling the computers, so the economics of heat recapture are really good."

Bjornsgaard said the idea of 'data fairness' was first promoted by computer giants Microsoft in 2011. It's taken Deep Green five years to reach the stage where their idea is operational and they are keen to expand.

Deep Green chief executive Mark Bjornsgaard beside the pool heated by his data center. /Deep Green
Deep Green chief executive Mark Bjornsgaard beside the pool heated by his data center. /Deep Green

Deep Green chief executive Mark Bjornsgaard beside the pool heated by his data center. /Deep Green

"The data center industry is well acquainted with the concept of immersion cooling, whereby you drop the computers in inert mineral oil instead of blowing cold air over them to cool down," he explains. 

"Getting the heat out of the oil is relatively straightforward. You just float the oil through a heat exchanger and the heat goes through the oil to the water."

The leisure center receives free heating in exchange for providing a place to house the data center equipment, which is about the size of a household washing machine.


How does it work?

Engineering is minimal and the system can be fitted within three days. "In the plant room we build a metal wall, put in the security fences that you'd find in conventional data centers. We literally build a very small data center in the plant itself and then run the pipes the wall, into the heat exchanger and into the pool," said Bjornsgaard.

With UK public swimming pools facing closure due to soaring energy bills, Exmouth leisure center manager Sean Day was happy for his pool to be included in the pilot.

The center had been expecting its energy bill to rise by $125,000 this year. Deep Green believes its heat donation will cut the pool's gas requirements by 62 percent and save $24,000 per year while reducing carbon emissions by 25.8 tonnes.

"During the installation we had only a small closure of the pool, but with timings and changeovers of sessions this was minimal," Day tells CGTN. "We were able to close early one evening and open slightly later the next day and work was completed.

"It works well and we have had no issues during installation or since going live. It's very early in the project but it takes up little space and doesn't affect any operations."

Swim England, the recognized national governing body for swimming, says it has been inundated by requests from by owners of other swimming pools to be included in the project. Many face closure due to energy price hikes.

Part of the data center at Exmouth leisure center. /Deep Green.
Part of the data center at Exmouth leisure center. /Deep Green.

Part of the data center at Exmouth leisure center. /Deep Green.

Bjornsgaard wants to inspire communities across the continent to work together to reduce their emissions. 

"Any large – or even small – business, anywhere that's affiliated to a town or village, should be linking their computer cloud and putting it into their local community," he says. "If we all think with that kind of reciprocity, then hopefully the world becomes a better place.

"In addition to being responsible for 3 percent of global carbon emissions, heating of buildings takes up 17 percent of global carbon emissions. Potentially a fifth of global carbon emissions could be cut by our system, so this stops being a nice-to-have and starts to be a necessity.

"Local authorities and central government are themselves huge consumers of cloud computing. Logic says that as soon as possible, governments of all shapes and sizes need to be heating their own facilities and offices. This gives them a route to net-zero, so they should give us a call."

Digital boilers are also offered by French firm Qarnot and Germany's Cloud&Heat, while heat from Amazon's AWS data center near Dublin is piped into the city, with the aim of heating more than 50,000 square meters of buildings.

Julian Allwood, Cambridge University professor of engineering and the environment, believes that the amount of energy used by data enters has been overestimated but welcomed the trial. He told the BBC: "If it's a sensible idea and it saves the leisure centre some money, then why not?"

Although the UK's Department for Environment, Food & Rural Affairs (DEFRA), failed to respond to CGTN's request for comment, Bjornsgaard hopes governments and business will show interest in digital boiler technology.

"Even if you don't want to save the polar bears or feel like you've got a moral obligation to your kids to save the planet, you should do this because it's significantly cheaper than putting a computer in a massive barn in the middle of nowhere. That just doesn't make any sense."


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