In Basel, the waste heat from a mini data center provides room heating and hot water in an apartment building. The innovative "server heating" functions as an intersection of the interests of IT customers and homeowners.
One of the strictest cantonal energy laws has been in force in the canton of Basel-Stadt since October 2017. Whenever possible, oil and gas heating systems on cantonal soil should be replaced by heating systems using renewable energy sources. This requirement is a headache for many homeowners. Because heat pumps or pellet heating systems are often difficult to implement in urban areas, and by no means all Basel districts can count on being connected to the district heating network. This also applies to the Neubad district, which is to the west of Basel's «Zolli». Here is an apartment building built in 1932, which was heated with gas until the 2019/20 heating season. The old boiler is still in the basement, but is only used as a backup and to cover peak loads. The new heat generator is housed in an inconspicuous chrome steel box. The rating plate says “chaudière numérique” – digital heating. In fact, the heat here is not generated from oil, gas or wood, nor is it extracted from the ambient air or the ground. Rather, the new heater uses the waste heat from several computers. However, there are no normal PCs in the housing, but powerful servers that perform significantly more computing operations and therefore also get much hotter than normal computers.
Asked cloud
“Server heaters like this have been around for a number of years,” says Stephan Février, the responsible project manager at the Basel-based energy supplier IWB. A colleague gave him the idea of starting a pilot project: “He works in the IT industry and has numerous servers in the basement of his house. These produce a lot of waste heat, so he asked me, half-jokingly, if you could use them for heating.”
In fact, the use of waste heat from servers has been an issue for a long time. In Switzerland, too, various larger settlements are heated using waste heat from data centers. So far, however, such solutions have only been available at Tier XL. The big advantage of the Basel project is its small scale. Because decentralized data centers and decentralized heat requirements go well together. This is also related to the widespread cloud technology.
The cloud (actually «cloud computing») has been around since the early 2000s. This refers to IT capacities, in particular storage and computing power, that are not tied to a specific location such as a physical data center. Rather, these tasks are distributed to different locations or data centers and offered to the users over a network connection. The big advantage of this technology is its scalability. Even the greatest need for computing power or storage space can be covered with the cloud. A serious disadvantage, however, is data protection. Digital data are subject to the laws of the country in which they are processed. Due to the geographical diversity of the cloud, however, data that is supposedly hosted in Switzerland can unexpectedly end up in the EU or even in the USA.
Safe and green
The French provider Neutral-IT, with whom IWB is working for the pilot project, solves this problem with decentralized data centers located on Swiss soil. One of them is the server heater. The data that is hosted or processed on it does not leave Switzerland, which ensures uniform data protection. The package is completed by the power supply with 100 percent green electricity from IWB. “This is attractive for IT customers because the CO2 footprint can be reduced and Swiss data protection laws are complied with. In turn, the offer is worthwhile for our customers because they do not have to worry about capacity utilization,” explains Stephan Février. "There is always enough calculation on the servers, so there is also enough heat available for heating and hot water."
Inside the chrome steel case there are up to a dozen "blades". This is what the modules are called on which, for example, a server or a switch (network distributor) is located. The blades are surrounded by an oil bath. Its heat is routed via a heat exchanger to a combined storage tank in the adjoining room. This heats the heating water and also feeds a fresh water station. This uses the hot water in the storage tank to heat up cold water using the continuous flow principle. In this way, the hot water can be processed exactly as required and highly efficiently, instead of having it available in a large storage tank for hours. The heat distribution, including the radiator, was left as is. The conversion work was initially limited to the technical rooms in the basement. The tenants are only affected by the removal of the old floor electric boiler.
Easy implementation
The conversion of the heating system was easy thanks to the generous amount of space. Oil heating was installed in the building even before gas heating. “The old tank had never been touched. We dismantled it and can use the old tank room for server heating," explains Stephan Février. The new storage tank and the fresh water station were easily accommodated in the adjoining room. For the tenants, comfort will increase, says Février: "You will have more space in the bathroom because the old boiler will be removed."
The pilot project is also worthwhile for homeowner Stefan Eugster Stamm: “Within a few years, we owners in the neighborhood have to find a replacement solution for fossil-fuelled heating systems. However, when installing a pellet or heat pump heating system, I would have had to adjust the insulation and heat distribution. With the server heating, I gain another five to eight years to start planning for it.» The tenants of the house, mostly young, were informed about the progress of the project and, according to Eugster Stamm, appreciate the new heating: "They think it's great to already be living in a house with CO2-neutral heating." The project is also worthwhile from an economic point of view: Despite the innovative technology, the costs for the house owner are about the same as if the normal gas heating system were to continue to be used.
New alternative?
The potential of using IT waste heat on a small scale can also be seen at Suissetec. However, Robert Diana, head of the heating department, has a few points to consider: “Residential buildings are expected to last at least 50 years. A classic heat generator should therefore last at least 15 years. If the technology for an isolated solution such as mini server heaters is no longer available in 5 or 10 years, a supplier like IWB can certainly find an alternative. However, private owners could get into trouble if the lifespan of the components is too short.”
No one can yet say what role server heaters will play in a few years' time.
However, Stephan Février from IWB is convinced of the possibilities of the technology: “Server heating systems are a great alternative to pellet heating systems or heat pumps. This is particularly interesting in districts that are not connected to the district heating network.” Although the pilot test is running in urban areas, the technology should not only be offered in Basel. "We're already receiving a lot of inquiries from all over Switzerland," reports Février, "that's why we want to offer the product nationwide." On the one hand, contracting is planned, i.e. the “flat rate heating” including operation and maintenance, but also systems operated by the building owner. As a result, building cooperatives don't necessarily have to wait until a data center is built nearby - perhaps they can also bring it into their own house. Further information at www.iwb.ch/serverheizung
