updated 12:10 pm EST, Tue December 2, 2008
Apple liquid cooler patent
Apple has filed for patents on two different liquid cooling technologies, both intended to apply to future notebooks. Current MacBooks use air cooling, driven by internal fans; while this is sufficient, it is thought that future components -- such as faster video cards and quad-core CPUs -- may force Apple to use more efficient (and possibly quieter) cooling. Active and passive methods are being suggested.
Under the active method, coolant would be forced to pass over or near the circuits in question, through the combination of a pump, pipes and drivers. The coolant could be made to shift between liquid and gaseous phases, but alternately, fluid could be mixed with gas bubbles or metal particles in order to improve heat transfer. Heat would ultimately be dissipated into the air through fin stacks.
A passive technique, also likely to be cheaper, would still rely on a pump but would tie a simple cooling system to a passive heat sink. Heat would be dissipated through an aluminum plate, specifically one located behind the computer's display. This would in theory help alleviate a problem common with notebooks, in which it becomes impossible to rest a notebook on a person's lap due to a hot metal base.