Hitachi has announced the commercial launch of its water-cooled notebook PC, a 1.8GHz mobile Pentium 4-based machine which uses its patented system to aid heat dissipation.

Most notebooks are cooled by air fans, and as processors have grown more powerful and begun to generate more heat, these fans have become more numerous, larger and faster. This has also meant that fans have become noisier.

The new Flora 270W Silent Model uses a water-based solution tank, instead of a fan or fans to cool down the processor. Hitachi announced a working prototype using this technology in February.

"The efficiency of a water cooling system and the air cooling system are about the same but the biggest difference is the noise the latter creates," said Masayuki Akabane, a Hitachi spokesman.

The water-based solution runs through a flexible tube that is placed over the chips and absorbs heat. The heated water solution is then sent to the display part of the notebook to be stored in a tank where it cools down.

Plastic panels separate these water-cooling elements from high-voltage areas, in case of a solution leak from the cooling system. The company also offers a three-year service guarantee for the product.

Hitachi is not the only company to be working on alternative cooling options, and PC Advisor has a review of a solution-cooled PC in our forthcoming October issue. The Signum Data Future Client is a desktop PC that uses a liquid filled heat pipe to transfer the heat from the processor to the case, which acts as a huge heat sink. This has the benefit of providing silent operation.

Hitachi's Flora water cooled notebooks use a 1.8GHz mobile Pentium 4 processor, 128MB of RAM, a 20GB hard disk drive and a 15in TFT screen, and are priced at ¥341,000 (£1,865). The Future Client is cheaper, as you would expect from a desktop PC, at just over £1,300.

Hitachi started taking custom orders from corporate customers at its online shopping site on Wednesday. The products are expected to ship on 30 September in Japan. The company can provide the product for corporate users outside Japan on demand. But it looking at market trends before deciding whether to launch the product for the consumer market. The Future Client is available for sale at