Fujitsu showed off a prototype of its upcoming high-power server that uses a closed-loop liquid cooling system to carry away the heat from its latest 16-core Sparc CPUs at Oracle’s OpenWorld conference in San Francisco this week.

The prototype cut-away piece of Fujitsu’s next-generation Sparc server had four Sparc 64-X CPUs running at three gigahertz. James Li, system software engineer at Fujitsu, said the machine’s cooling system was “a hybrid liquid-and-air system.”

The liquid, driven by “micro-pumps”, runs over the CPUs in a closed loop. The heat is pushed out to a heat exchanger, which is then cooled by fans.

The server will still require traditional external data center cooling, but there are other advantages to its internal cooling design. One of them is space.

“We can put everything much closer together because we don’t have to worry about the airflow over the CPUs,” Li said. The only places where room had to be made for air flow were over the DIMMs (dual in-line memory modules) and around the radiator.

The other advantage is weight reduction. “If we had to go with a heavy-metal heat sing over the CPUs, it’s a lot of weight, so we’re saving about 55kg going with this kind of system,” Li said.

The server will be well suited for heavy-workloads and highly scalable deployments by companies in the financial-services industry, telecommunications or customers who require high-performance computing.

Fujitsu is planning to bring the server to the market in early 2013, but the plan may change, he said.