Aquasar

The Aquasar supercomputer first came in to use at the Department of Mechanical and Process Engineering, at the Swiss Federal Institute of Technology Zurich (ETH Zurich) in 2010. ETH Zurich is one of two schools that is a part of the Swiss Federal Institute of Technology with the other school being ETH Lausanne. High energy efficiency, environmentally friendly computing, and high computing performance were a few of the main interests in the development of the Aquasar. A key part of being environmentally friendly was the focus of attempting to lower the output of carbon dioxide emissions. 50% of an air-cooled data center's energy consumption and carbon pollution actually comes from the cooling system of the data centers rather than from the actual computing process. The creation of the Aquasar started in 2009. It was a part of IBM's First-Of-A-Kind (FOAK) program (a program encouraging IBM researchers and clients to develop potential new technologies to assist with real world problems in business).[2] One other supercomputer would later use the same idea of a hot water coolant in their developments, the SuperMUC supercomputer. Future development of more powerful supercomputers also explored the possibilities of using on-chip cooling as their main cooling source to achieve greater computer efficiency.

An academic paper written in 2018 explored the many possibilities for developing new Exascale computing (a higher scale performance of supercomputing). Exascale supercomputers will be needed in future computing which means high energy efficiency and high cooling efficiency are needed out of these supercomputers to achieve peak performance. The scientists looked to the possibility of "on-chip" cooling, inspired because of the Aquasar supercomputer.[4]

The Aquasar contains water-cooled IBM BladeCenter Servers (IBM's versions of the bare-bones server computer) and air-cooled IBM BladeCenter Servers in order to contrast the performance of the hot-water coolant and the air cooling. The air-cooled and water-cooled BladeCenters are made up of IBM BladeCenter H Chassis, using a combination of IBM BladeCenter QS22 Servers and IBM BladeCenter HS22 Servers in both of the BladeCenter systems.[2] The system employs 6 teraflops (flops are a unit using to determine computing speed) and attains an energy efficiency of about 450 megaflops per watt.[2][5] Pipelines connect the individual BladeCenter servers to the main network where it is then further connected to the water transportation pipeline network. These pipelines can be disconnected and reconnected too. 10 liters of water for cooling are used with a pump, producing a flow of approximately 30 liters per minute.[5] A sensor system has also been installed into the Aquasar system to further monitor the performance. The scientists hope to optimize the system using the information they obtain from these sensors.[3]

The warm water cooling system is a closed-loop system. The coolant is constantly being heated up by the processing units. The warm water is then cooled back down via a heat exchanger (a way of transferring heat between fluids). The transferred heat then gets directly used into the heating system of the building such as in the ETH Zurich building, thus allowing the heat to be reused effectively.[5] Up to around 80% of the produced heat is recaptured and reused to heat the buildings.[6] At the SuperMUC supercomputer, the heat that is created by the hot water coolant is used to further heat the rest of the campus, saving the Leibniz-Rechenzentrum campus around $1.25 USD million per year. Approximately nine kilowatts of thermal energy are put into the heating system where the waste heat will later be used to heat the ETH Zurich building.[5]