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This startup has engineered a clever way to reuse waste heat from cloud computing

Heata is now using these busy servers to heat water for homes.

The Heata unit installed next to a home washing machine and laundry basket
Luigi Avantaggiato

Using heat generated by computers to provide free hot water was an idea born not in a high-tech laboratory, but in a battered country workshop deep in the woods of Godalming, England.

“The idea of using the wasted heat of computing to do something else has been hovering in the air for some time,” explains Chris Jordan, a 48-year-old physicist, “but only now does technology allow us to do it adequately.

“This is where I prototyped the thermal conductor that carries heat from computer processors to the cylinder filled with water,” he says, opening his workshop door to reveal a 90-liter electric boiler. “We ran the first tests, and we understood that it could work.” Jordan is cofounder and chief technology officer of Heata, an English startup that has created an innovative cloud network where computers are attached to the boilers in people’s homes.

aerial view of neighborhood and park space in Godalming
View of Godalming, Surrey, UK. Over 4 million people in the UK struggle to afford heat.
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Next to the boiler is a computer tagged with a sticker that reads: “This powerful computer server is transferring the heat from its processing into the water in your cylinder.” A green LED light indicates that the boiler is running, Jordan explains. “The machine receives the data and processes it. Thus we are able to transfer the equivalent of 4.8 kilowatt-hours of hot water, about the daily amount used by an average family.”

When you sign up with Heata, it places a server in your home, where it connects via your Wi-Fi network to similar servers in other homes—all of which process data from companies that pay it for cloud computing services. Each server prevents one ton of carbon dioxide equivalent per year from being emitted and saves homeowners an average of £250 on hot water annually, a considerable discount in a region where 13% of the inhabitants struggle to afford heat. The Heata trial, funded by a grant from Innovate UK, a national government agency, has been active in Surrey County for more than a year. To date, 80 units have been installed, and another 30 are slated to have a boiler to heat by the end of October.

Chris holding a blowtorch at a workbench
Heata’s CTO, Chris Jordan, in his workshop.
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A laser cutter produces insulation for the Heata unit, which harnesses excess heat from cloud computing.
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A batch of heat pipes at Heata Labs.
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Dave, a radio engineer, tests the operation of the server at Heata Labs.
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Parts of the Heata unit before assembly.
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Andrew kneeling to work in an attic
Andrew, a mechanical engineer, installs the Heata unit in an apartment in Surrey. At 75% utilization, the Heata unit will provide around 80% of an average UK household’s hot water.
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James, a 46 year old computer engineer, working at his home computer
Homeowner James Heather on his Heata: “We no longer need the energy for cooling the compute units, and we don’t need the energy for heating our hot water either, because we’re using the waste heat from the unit to do it.”
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Heata’s solution is “particularly elegant,” says Mike Pitts, deputy challenge director of Innovate UK, calling it a way to “use electricity twice—providing services to a rapidly growing industry (cloud computing) and providing domestic hot water.” The startup is now part of Innovate UK’s Net Zero Cohort, having been identified as a key part of the push to achieve an economy where carbon emissions are either eliminated or balanced out by other technologies.

Heata’s process is simple yet introduces a radical shift toward sustainable management of data centers: instead of being cooled with fans, which is expensive and energy intensive, computers are cooled by a patented thermal bridge that transports the heat from the processors toward the shell of the boiler. And rather than operating with a data center located in an energy-intensive location, Heata works as an intermediary for computing: it receives workloads and distributes them to local homes for processing. Businesses that need to process data are using the Heata network as a sustainable alternative to traditional computing.

The company has created what Heata’s designer and cofounder Mike Paisley describes as a diffuse data center. Rather than cooling a building that holds many servers, he explains, “our model of sustainability moves data processing [to] where there is need for heat, exploiting thermal energy waste to provide free hot water to those who need it, transforming a calculation problem into a social and climatic advantage.”

The people involved in the Heata experiment are diverse in age and household composition, and their reasons for participating are varied: a need to save on bills, a love for the environment, an interest in helping combat climate change, and fascination with seeing a computer heat the water.

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The Heata team among the trees at Wood Farm, Godalming, where the idea originated.
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Among the satisfied customers is Helen Whitcroft, mayor of Surrey Heath. “We started reducing our carbon footprint many years ago by installing photovoltaic panels,” she says. “We recently bought batteries to store the energy we produce. Curiosity also moved us: it didn’t seem possible that a computer could heat water, but it works.”

Luigi Avantaggiato is an Italian documentary photographer.

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