CLAIX

The information technology sector is now responsible for a higher annual share of global greenhouse gas emissions than the aviation sector. This trend is also evident at RWTH, in particular the IT Center, which accounts for around 10% of the University’s entire power consumption, with the majority resulting from the operation of high-performance computers.

That is why energy efficiency was an important factor when purchasing the Cluster Aix-la-Chapelle (CLAIX) high-performance computer, funded by the federal and state governments, with the installed system achieving an energy-saving advantage of around 25% compared to less efficient models. This is equivalent to a CO2 saving of around 600 metric tons  in CO2 emissions for the annual operation (the Cluster’s power consumption is currently approx. 700 kW).

The computer is operated in a newly upgraded energy-efficient supply infrastructure. The central feature of this system, funded as part of the CLAIX research project, is an open-air-cooled water circuit for the direct cooling of the computers. This means that the high-performance computers do not require any mechanically generated cooling, making it possible to limit the amount of energy required to cool the computers to below 10% of the energy consumed. Compared to machine cooling, this represents an annual saving of up to 1,000 metric tons of CO2 (with estimated emissions of around 400 g CO2/kWh with the German energy mix).

Due to a lack of suitable consumers in the immediate vicinity, it is currently not possible to economically exploit the waste heat from the computers. In the plans for the carbon-neutral Campus West expansion site, residual heat exploitation when using the next data center generation is a fixed component of the energy concept. As a result, high-performance computer use will make a more significant contribution to saving resources at RWTH in the future.