Parisian radiators with brains

Qarnot, a small company based outside Paris, France, is developing computing products that generate heat close to the end user

The potential to use waste heat from large data centres is limited if computing is not located near where heat is needed. Start-ups are offering innovative decentralised computing solutions in or near homes, offices and other buildings

Solutions on the market aimed at bringing together producers of waste heat and their customers include computing heaters and devices containing embedded graphics cards for mining crypto-currencies, such as Bitcoin. These ultra-distributed approaches are gaining some traction, but remain niche. This could change as so-called “edge” computing is adopted with computers becoming more common in everyday objects, from refrigerators to self-driving cars.

“Computing everywhere, computing anywhere,” is the mantra of Qarnot, a small company based outside Paris, France, which has developed computing products that generate heat close to the end user.

Computing capacity

Qarnot’s computing heater is a unit that can be placed against a wall in a home or office. Rated at 650 watts, pay-back time is about ten years in terms of saved heating bills, says the company’s Quentin Laurens. About 1000 units had been sold as of February 2019, including to heat a renovated social housing building near the Eiffel Tower and social housing and public offices in the city of Bordeaux in the south of France. On the other side of the equation, Qarnot has sold the heaters’ computing capacity primarily to big French banks, including BNP Paribas, Société Générale and Crédit Agricole, to 3D animation studios — Disney is a client — and laboratories.

Qarnot says it can offer banking clients computing capacity at a rate two to four times cheaper than from more conventional sources because infrastructure is minimal and hardware paid for by heating clients, while helping clients reduce their carbon footprint and meet sustainability goals. France’s ELAN housing law, passed in 2018, for the first time recognises waste heat in national energy efficiency guidelines for new or renovated homes, a potential boon for Qarnot’s business.

The radiators are especially suitable for colder climates such as Finland, where home and office heating is often needed for most of the year, says Qarnot. If and when heating is not required, one solution is to run the computer’s central processing unit at a lower frequency so no heat is released, says Laurens. Alternatively, computing can be diverted to Qarnot’s own computing infrastructure or conventional data centres. Qarnot selects these on the basis of whether they use renewable energy.

As for the issue of cyber-security, the data in its units is encrypted and always erased after a computation is concluded, says Laurens. Nor do the heaters store data, minimising opportunities for hacking. Only the banks’ less sensitive computations are conducted in the heaters, such as risk analysis rather than high-stakes financial trading, adds Laurens. He accepts hacking is part of the job: “Google gets hacked. Qarnot gets hacked.”

Canadian mining

Data mining is the process used to create digital Bitcoin tokens and is extremely energy intensive, estimated globally to use as much electricity as Singapore. One single Bitcoin transaction has a footprint of almost 200 kilograms of carbon dioxide. This creates a great deal of residual heat, which is already decentralised, having no central bank.

Across the sea in another French speaking city, Quebec, Canada with its cool climate and cheap hydro power, has touted itself as an ideal location for data centres. Success in luring energy-hungry crypto-currency miners to its shores means that as of August 2018 new miners entering the province have to pay C$0.15 (€0.10) a kilowatt hour (kWh) for electricity, around double the rate paid by residential customers. A good incentive for reusing waste heat.

Heat mining

One of these companies, Blockchain Lab, offers so-called heatmine units that contain graphics processing units for crypto-currency mining. It partners with buildings needing significant amounts of heating such as churches, greenhouses or warehouses. A unit, placed for free in a partner’s building, is about two metres by two metres by one metre. It contains computer processors and about 100 graphics cards as well as a water heater. The system can provide some 75,000 British thermal units (BTU) an hour, enough to heat a building of up to 300 square metres for 24 hours.

Blockchain Lab pays for the unit’s electricity and uses its computing capacity, in turn charging the partner C$0.35 a kWh (€0.23/kWh) for the waste heat. In the warmer months, if less heating is needed, the waste heat can be vented, stored or employed for year-round uses such as warming a swimming pool, says the company’s Benjamin Forte.

One of the most unusual uses of heatmine is in a cricket farm where the insects need constant heat whatever the season.

Writer: Ros Davidson

This story first appeared in FORESIGHT Climate & Energy’s Technology section