Heata offers free hot water by mounting servers on people's water tanks

Novel use of waste heat by UK company – but it's still in trial

Heata has developed a novel way to use the waste heat generated by servers: mounting them on domestic hot water tanks to cut energy bills for homeowners.

The company, whose services now include cloud compute, 3D rendering and ways to help landlords improve the efficiency of their housing stock, has hooked up with cloud provider Civo to offer the compute resources for running some workloads.

Heata started as a project within energy company British Gas to help customers living in fuel poverty, something many can sympathize with at the moment. It has now been spun out with investment from British Gas, Innovate UK, and also Civo, a cloud-native service provider that focuses exclusively on workloads running with Kubernetes.

The initial concept developed by the company involved using heat generated by Bitcoin mining rigs, according to Heata Co-founder and CTO Chris Jordan.

"We literally put a Bitcoin miner in a barrel of mineral oil and plumbed it up to a radiator," he told The Register.

We literally put a Bitcoin miner in a barrel of mineral oil and plumbed it up to a radiator

British Gas liked the idea that you could make money out of compute assets, he said, and the team moved on to a new approach that needed no plumbing, which was to attach a server to the outside of a hot water cylinder to help heat the water.

"Over the last two or three years, we've just been developing the idea, seeking funding and running trials," Jordan said.

This is where the project is now, at the trial stage involving about a hundred units in individual homes for the next three to six months. The company will allow customers to use the compute nodes and get feedback around performance and reliability, as well as demonstrating what kind of savings the hosts of the hardware get against their energy bills and the CO2 emissions this may have saved.

"Because it's a government-backed trial, we're putting the units for free in people's houses. And they'll be getting free hot water from it for a year," Jordan said.

"There's a trial page up on our website that people can sign up to, if they're in the South East of England, and then they can get involved. We've still got some spaces left on that," he added.

For the trials, those looking to host one of the units will need to have an internet connection that the server can use to link back to Heata, but the company said it is in talks with several fiber broadband providers to provide connectivity to the homes hosting its units.

The hardware itself comprises a box that houses an ATX motherboard, with a large metal plate that is bonded to the domestic hot water tank using thermal epoxy. The plate is linked directly to the heatsinks on the CPUs, which in the trial are refurbished Xeon processors providing a total of 56 cores, Jordan said.

"Basically what we're aiming for is to match the output power of the CPUs to about 80 percent of what the hot water usage of a household with a family of four will be, that's sort of the sweet spot," he added.

Installation can be done by a heating engineer or an electrician, as the unit is simply a "black box" that just needs fitting and connecting to power and a network, Heata claims.

An important point is that the unit provides additional energy for heating water, so the host will not be left without hot water if the unit fails, and they should have no need to do anything with the device at all.

The company claims that each unit could save one tonne of carbon per year

On the compute side, Heata is being careful about the kind of workloads it pitches the compute nodes for, since it effectively has a bunch of individual servers that may be distributed around the country.

"We're not looking at serving real time workloads, we're not doing websites, databases, message queue servers," Jordan explained. "Our ideal job is; here's a chunk of data, go and process that for some hours. And here's the result," he said.

This could still prove useful for 3D rendering workloads, finite element analysis, computational fluid dynamics, and others where there is a lot of CPU or GPU processing, he claimed.

The partnership with Civo will also see Heata's units made available as an option to Civo customers as edge nodes to run workloads. Civo's focus on Kubernetes means that workloads can be deployed and managed using Suse Rancher as the orchestration platform.

Civo CEO Mark Boost said his company is currently developing a functions-as-a-service (Faas) or so-called serverless compute offering that would "sit very nicely on something like Heata".

"There's lots of possibilities we can explore as a joint sort of collaboration. Obviously, there's some ones we can get up and running very quickly, in terms of the batch jobs and render jobs and things like that. And it's a bit more complicated in terms of real time stuff," Boost said, but added that this will evolve over time.

"At a time of soaring energy prices, I am particularly committed to being the bridge between the world of tech and areas like social housing where the need for solutions to the deepening cost of living crisis is being felt most acutely," Jordan said.

This scheme by Heata is just one of a recent wave of novel ideas to make use of the waste heat generated by servers.

Back in March last year, Microsoft and Finland's largest energy company unveiled plans to warm homes and businesses near Helsinki using heat generated by a new datacenter. A similar scheme was announced in The Netherlands by datacenter operator QTS to serve the Groningen district heating grid.

Last year, The Register also reported how a Korean company called Tomorrow Water aims to colocate datacenters with sewage treatment plants so that heated water from the datacenter can be used to boost waste water processing, with some of the treated water fed back to the datacenter for cooling purposes.

Most bizarre of all, however, was the datacenter in Hokkaido in Japan using snow to cool its IT infrastructure then using the resultant meltwater, heated to 33°C (91.4°F), to farm eels for human consumption. ®