Improving the air with economical fans
Fan: The LRZ is increasing its energy efficiency by modernising its fans. AI photo: Horizon/Adobe Stock
Energy-efficiency in data centres is not only achieved by improving computer hardware, but even more so by modernising the immediate environment and building infrastructure: together with fan specialists, the LRZ facility management team is currently optimising the ventilation system in the compute rooms.
At the Leibniz Supercomputing Centre (LRZ) cool, clean air is provided by a dozen or so grey, double-door cabinets located in the technical areas and connected to the compute rooms by air ducts. From top to bottom, they contain filters, cooling registers and fans with separate motors: "In the compute rooms, the warm air is sucked in at the top, passed through the filter and the cooling coil, where it is cleaned of dust and cooled down," explains Pascal Weibel, LRZ engineer for building services. "The fan provides the necessary pressure differential to push the air through the cooling unit and distribute it over the raised floor in the compute room."
While the LRZ uses hot water to cool its supercomputers, this technology cannot be used for all systems in the compute centre; hard drives and data storage on magnetic tape still have to be cooled by air. The design of the air circulation cabinets is outdated and is currently being renovated: "Simply replacing or renewing the units no longer works," explains heating engineer Martin Ruhland from the LRZ. "We therefore worked with a company specialised in fan and ventilation technology to find new solutions.
More efficient technology reduces energy consumption
The LRZ moved to the Garching research campus in 2006, and the air handling units date back to that time. However, ventilation and building technology has evolved and become more digital: "We are happy about every component that we can control and maintain remotely," Weibel and Ruhland say. "With our facility management monitoring system, we can't check how and whether the air-cooling units are working properly. If they fail, no emergency call would be triggered. In addition to the cooling system, the control system and the filters also had to be optimised. This wasn't an easy task, as building services are usually interlinked, so the new fans, for example, had to be installed vertically on top of each other instead of horizontally next to each other as usual: "They don't need a V-belt, their motor is directly connected to the fan shaft," explains Weibel. "This saves electricity and helps us to reduce costs.”
The LRZ is working with Ziehl-Abegg to modernize the ventilation system and the cabinets. This company builds ventilation and control technology and specialises in modernising old systems: "We are happy to respond to customer requests in the project business and in development," says Torsten Friedrich, responsible for Business Development Retrofit. "This includes mechanical changes to the ventilation technology and, increasingly, specific parameters of our products or software.”
Modernise instead of rebuild
Modernisation poses different challenges than new development: Engineers and technicians have to make do with a given space, as in the case of the LRZ air-recirculation cabinets, and also check the suitability of existing products. The first step was to measure the room and air conditions in order to qualify the fans and other components and adapt them to the conditions. "Depending on the type, condition and tension of the V-belt, a fan can quickly consume five percent more energy, and outdated motor technology or low impeller efficiency also cost additional power," observes Willibald Walter, development engineer and project manager of Ziehl-Abegg. "Our directly driven ECblue fans often consume 25 to 30 percent less energy than the existing fan driven by a V-belt. And because there is no need for a filter system to separate the V-belt debris from the air, the energy requirement is reduced even further.
In addition to the new fans and finer filters, the grey boxes in the LRZ's air recirculation cabinets are also being replaced: they contain programmable logic controllers, simple computers that are installed right next to machines and other equipment, offer many inputs and outputs for cables and plugs, and enable remote control, in this case of the ventilation. Here, sensor data from the computers and from the computer rooms of the LRZ are fed into the programme for the control technology of the LRZ.
A prototype for the new interior of the LRZ's air circulation cabinets has already been built in Künzelsau and will soon be installed in Garching. Collaboration brings benefits to all. The LRZ can further reduce its energy requirements for cooling, while the vertical positioning gives Ziehl-Abegg more options for placing its fans in older racks: "Of course," says Retrofit specialist Friedrich, "we hope to receive follow-up orders from the LRZ and other companies with similar air systems and tasks.” (vs)