Aquasar
| Company type | Prototype supercomputer |
|---|---|
| Industry | Supercomputing |
| Founded | 2009 |
| Headquarters | Zurich , Switzerland |
| Products | Supercomputer with hot water cooling technology |
| Parent | IBM Labs, ETH Zurich, ETH Lausanne |
Aquasar represents a prototype supercomputer created through a collaboration between IBM Labs, ETH Zurich, and ETH Lausanne in Switzerland. Diverging from conventional supercomputers that rely on air cooling, Aquasar utilizes hot water cooling to boost computational efficiency. Additionally, it incorporates an air-cooled segment designed to benchmark and compare cooling effectiveness.
Initiated in 2009 as a three-year joint effort, the project sought to merge high computational performance with energy conservation and ecological advantages. A distinctive feature of the system is its ability to repurpose waste heat from the liquid cooling process to supply heating for the building, potentially reducing operational costs. This strategy promotes eco-friendly data center practices while sustaining advanced computing capabilities.
Development
Aquasar was initially installed in 2010 at ETH Zurich’s Department of Mechanical and Process Engineering, part of the Swiss Federal Institute of Technology network alongside ETH Lausanne. The development emphasized achieving high energy efficiency, environmentally sustainable computing, and robust performance. A key objective was to minimize carbon dioxide emissions, recognizing that cooling accounts for about half of the energy consumption and carbon footprint in air-cooled data centers. Launched in 2009 under IBM’s First-Of-A-Kind (FOAK) initiative, Aquasar introduced hot water coolant technology that later influenced the design of the SuperMUC supercomputer. Upcoming supercomputers are investigating on-chip cooling techniques to further improve efficiency.
Advancements in Hot Water Cooling
A 2018 scholarly investigation explored solutions for Exascale computing, which requires exceptional energy-saving measures and cooling methods to achieve optimal performance. Drawing inspiration from Aquasar, researchers identified "on-chip" cooling as a promising approach for future supercomputer architectures.
Cooling
Aquasar employs cutting-edge "on-chip" cooling through micro-channel coolers directly affixed to its processors, which are the primary heat sources. These micro-channels, each less than 1 millimeter wide, circulate warm water at around 60 °C (140 °F). Due to water’s superior thermal conductivity and specific heat capacity, it can absorb approximately 4,000 times more heat than air, enabling effective thermal management. This system keeps processors below their maximum safe temperature of 85 °C (185 °F), enhancing performance while lowering environmental impact.
Hardware
The Aquasar system integrates both water-cooled and air-cooled IBM BladeCenter Servers to evaluate the performance differences between hot-water and air cooling methods. It employs IBM BladeCenter H Chassis populated with a combination of QS22 and HS22 servers. Delivering a total of 6 teraflops in processing power, the setup achieves an energy efficiency near 450 megaflops per watt. Network connections and water distribution pipelines link the BladeCenter servers to their respective infrastructures, allowing flexible disconnection and reconnection. The cooling circuit circulates 10 liters of water at roughly 30 liters per minute via a pump, with sensors continuously monitoring system parameters to maximize efficiency.
Heat Recovery
Aquasar employs a closed-loop warm water cooling mechanism where the heated coolant passes through a heat exchanger, allowing heat to be directly transferred to building heating infrastructures such as those at ETH Zurich, facilitating efficient heat reutilization. Up to 80% of the generated thermal energy is reclaimed for space heating purposes. At the SuperMUC supercomputer facility, the coolant’s waste heat is utilized to warm the campus, resulting in annual savings of approximately $1.25 million for the Leibniz-Rechenzentrum. Nearly nine kilowatts of thermal power are delivered to the heating network, further lowering operational expenses.
Advantages
Data centers hosting supercomputers typically allocate about half of their electrical consumption to traditional air cooling methods, which significantly drives up energy usage. Worldwide, computing activities are estimated to consume around 330 terawatt-hours of electricity. The Aquasar cooling system achieves an energy reduction near 40% compared to conventional air-cooled supercomputers. By employing liquid cooling, it enables the recovery and reuse of heat within heating systems, leading to an approximate 85% decrease in carbon emissions through diminished reliance on fossil fuels. This strategy also results in operational costs that are roughly one-third of those associated with standard air-cooled datacenter supercomputers.