Faster chips generate more heat, and this can cause trouble if the heat is not dissipated. Notebook PCs normally use a fan bolted on top of the processor. However, Hitachi has developed a water-cooling system, which it says works more efficiently and makes less noise than a fan-based system.
Inside the prototype notebook PC, a narrow stainless steel tube circulates a water-based solution between the chip and the display to absorb the heat. In doing so, the temperature of the solution can reach 60°C, according to Nanako Uchiyama, a spokeswoman for Hitachi.
The hot water solution gets pumped up to the notebook display, where it releases its heat. The display panel has a water tank behind it, and a pump resides in the main body of the machine.
While the water-cooling system is more efficient and less noisy, it tends to degrade and evaporate during operation. The company has worked on improvements to the quality of the water solution and to the tube.
The system has already been used for the company's supercomputers, Uchiyama said, but the improvement of the quality of the water-based cooling system was necessary before it could be applied to notebook PCs because, unlike supercomputers, customers demand that they should be maintenance free, she said.
Compared to conventional air-cooled notebook PCs, the price and the size of the water-cooled notebook PC will remain about the same. However, she claimed, the water-cooling system should have a life cycle that is 1.7 times longer than an air-cooled system.
Hitachi hopes to commercialise the product between July and September 2002 for corporate users in Japan and plans to adopt the system for other products such as servers and plasma display panels (PDPs), which also generate large quantities of heat and require a lot of cooling, Uchiyama said.
The company also expects its water-cooling system to become a de facto standard throughout the industry and is currently in licensing talks with several component manufacturers.