Open Access Article

Title: Direct-to-chip liquid cooling for reducing power consumption in a subarctic supercomputer centre

Authors: Seppo J. Ovaska; Roy E. Dragseth; Svenn A. Hanssen

Addresses: Department of Electrical Engineering and Automation, Aalto University, FI-02150 Espoo, Finland ' Department of Information Technology, UiT The Arctic University of Norway, N-9037 Tromsø, Norway ' Department of Information Technology, UiT The Arctic University of Norway, N-9037 Tromsø, Norway

Abstract: Reduction of data centre power consumption is a timely challenge. Waste heat reuse is another focus area when developing energy efficient and sustainable data centres. And these two issues are interconnected through liquid cooling of server racks and/or direct-to-chip liquid cooling. Both of these solutions make it possible to transfer a significant proportion of the waste heat energy back to profitable use. Nevertheless, the heat reusing opportunity is not the only benefit direct-to-chip liquid cooling may offer. Another benefit is the notable reduction of power consumption related to cooling fans associated with server blades and rack-level cooling systems. To evaluate this benefit, we performed power consumption and performance measurements in a subarctic supercomputer centre hosting a cluster of 632 blade nodes. Our study concentrated on a 47-node subset that we analysed when the servers were executing the LINPACK benchmark. Our conclusion is that direct-to-chip liquid cooling can reduce the total power consumption, in this case, up to 14.4% depending on the inlet air temperature.

Keywords: data centres; direct-to-chip liquid cooling; power consumption; subarctic climate; supercomputers; waste heat reuse; waste heat recovery; cooling fans; performance measurement; inlet air temperature.

DOI: 10.1504/IJHPCN.2016.076269

International Journal of High Performance Computing and Networking, 2016 Vol.9 No.3, pp.242 - 249

Available online: 13 Apr 2016 *