Last year we wrote about ionic wind engine research that was conducted at Purdue University and allowed the team to increase the heat-transfer coefficient of a regular fan by 250 percent, thus significantly improving the cooling solution. Since then chips have definitely not become any cooler. The power envelope for individual cores might have decreased due to the re-emergence of simpler architectures with shallower pipelines, but with chip companies squeezing ever more cores into smaller packages, the heat problem is not going away any time soon. To compound the problem, keep in mind that for all these cores to perform useful work, they need to constantly be supplied with data, which leads to more I/O circuitry. The I/O circuitry in turn often times consists of many analog blocks that generally don’t scale very well with voltage, leading to more heat.

But rest assured, where there are interesting problems to be sovled, smart minds somewhere are working on doing just that. As happens to be the case, once again researchers at Purdue University have developed a technology that through the use of microjets enables them to deposit liquid into tiny channels on the chip surface resulting in a high-performance cooling solution. Conventional chips generate about 100 watts per square centimeter and can be air cooled via heat sinks and fans. Liquid cooling solutions are generally limited to about 200 watts per square centimeter. The Purdue team claims that their new cooling technology will allow chips with a power density of up to 1,000 watts per square centimeter. The key for achieving this type of cooling is a non-conductive liquid called hydrofluorocarbon. This fluid is pumped into the tiny channels on the chip surface via microjets through holes in the metal plate that sits on top of the channels. As the liquid circulates through the channels, it heats up until it momentarily becomes a vapor, which significantly enhances the cooling process. The micorjets ensure that the fluid is evenly distributed along the channels. This avoids the previous pitfall of fluids traversing chips from one side to the other, heating up along the way and thus losing their cooling ability.

Of course, the question has to be asked whether it will be possible to commercialize this technology. In specific niches, such as super-computing, where cost usually takes a backseat to performance, this cooling solution might indeed be acceptable. However, unless the technology can be made affordable enough so that major chip vendors can incorporate it into their products without alienating their consumers, it will likely fall by the wayside. I don’t have any chip packaging background and as such estimating the costs of this approach in its present form are beyond me, however, something tells me that they are not insignificant.