All computers generate heat as they work. Cloud&Heat has developed technology that harnesses this wasted energy and uses it to heat buildings and water. The associated network of servers forms a cloud-based computing service.

It all began with a house. When computer scientist Christof Fetzer from Dresden started to plan an eco-friendly passive house for his family, his colleague Jens Struckmeier, a physicist, was intrigued by the thought of capturing the waste heat generated by a bank of computers in the Fetzers’ new home. Could it be used to heat the house? Could the idea be scaled up to heat many more buildings in the same way? Struckmeier worked with Fetzer to design a prototype server cabinet that could accommodate the computers. It was constructed to allow the waste heat to pass through a heat exchanger and feed into a building’s heating and water system. In buildings with a central ventilation system, it also needed to be able to route the warm air from the servers directly into the system, or to channel the heat to the outside in a cost-efficient manner. This meant there would be no need for separate cooling systems for the computers, thus saving energy and money.

The greenest cloud in the world

Finally, the idea was to link the distributed servers via the Internet to form a virtual computer centre. Struckmeier developed a simulation program to establish how many server cabinets would be required to heat a building, depending on its energy footprint and size. Now all the pair had to do was set up a company and appoint a managing director to raise seed capital. They brought businessman René Marcel Schretzmann on board and founded AoTerra in 2011. The company now combines both strands of the business under its new name Cloud&Heat and is based in the north of Dresden. “We aim to become one of the most important cloud providers in Europe and beyond,” says Schretzmann, declaring that the firm already operates the greenest cloud in the world. The company’s server cabinets save up to ten tonnes of CO2 per unit per year compared to conventional computer centres. Sales reached EUR 1 million in 2013, with profits expected in late 2015. Schretzmann acquired capital funding not only from the local bank and the Startbahn Ventures start-up fund, but also from German crowdfunding platform Seedmatch, which generated EUR 1 million.

Free heating and hot water for 15 years

The funding has enabled Cloud&Heat to install 464 servers across Germany to date and the company is currently putting all its efforts into building up its cloud services customer base. “We now have 75 customers,” says Schretzmann. “They are mainly technology-focused start-ups, SMEs and individuals, but we also work with major companies.” Cloud&Heat is able to offer competitively priced cloud services as it does not need to build any computer centres. Property owners also enjoy attractive benefits when purchasing a server cabinet, which costs around EUR 12,000. Cloud&Heat pledges to use its technology to heat properties and supply them with hot water free of charge for at least 15 years.