Computer Clusters That Heat Houses

They have been used to model climate change, forecast economic trends, and simulate the intricate complexities folding proteins. Now IBM has something new in store for high-performance computers: heating buildings.

Thanks to a novel on-chip water-cooling system developed by the company, the thermal energy from a cluster of computer processors can be efficiently recycled to provide hot water for an office, says Bruno Michel, manager of advanced thermal packaging at IBM's Zurich Research Laboratory, in Switzerland. The goal, he says, is to improve the energy efficiency of large computing clusters and reduce their environmental impact.

A pilot scheme involving a computer system fitted with the technology is expected to save up to 30 tons of carbon dioxide emissions per year--the equivalent of an 85 percent carbon footprint reduction. A novel network of microfluidic capillaries inside a heat sink is attached to the surface of each chip in the computer cluster, which allows water to be piped to within microns of the semiconductor material itself. Despite its close proximity to the circuitry, there is no danger of leakage, says Michel, because the capillaries are hermetically sealed. By having water flow so close to each chip, heat can be removed more efficiently. Water heated to 60 °C is then passed through a heat exchanger to provide heat that is delivered elsewhere.