Peltier Condensation Prevention

Article by Jason on 09.09.2003

Background information:

Overclockers have for many years sought better cooling solutions for their CPU's. Larger and more active cooling methods for heat sinks became popular, and shortly thereafter water-cooling came onto the scene. Most of the mainstream computer users would more readily purchase a HSF rather than the more expensive water solution. This situation is slowly changing and for a number of reasons.

1. Effective HSF's for your CPU are getting larger and heavier posing the potential to crush your CPU core.
2. The noise produced by most of the effective HSF's is enough to simulate a small vacuum cleaner.
3. The thermal output of current CPU's is on the rise with no change in the foreseeable future.
4. Water based systems are gaining acceptance due to overall quality and effectiveness.

The following general order of cooling effectiveness is as follows (on order of most to least effective):

1. Liquid Nitrogen
2. Phase Change
3. Water Cooled Peltier
4. Heat sink Fan Cooled Peltier
5. Water Cooling
6. Heat sink Fan
7. Passive Heat sink (No fan)

As you can see Liquid Nitrogen is the most effective means of cooling a processor, of course the hazards, cost, and reliability factors usually outweigh any possible gains. Phase change is the next most effective, however, phase change cooling is also expensive and consumes more electricity than all other means of cooling. This brings most overclockers to the use of peltiers and water for their cooling needs. Water systems are an effective means of re-directing the flow of heat to a place where the heat may be eliminated by means of a radiator. Water systems are however limited by the fact that no matter what a user has done a water system in and of itself cannot reduce the temperature of a CPU below the surrounding ambient temperature.

The most effective overclocking is achieved through the use of sub-ambient cooling of the CPU. Peltiers have the capability of providing those sub-ambient temperatures depending upon the strength (in wattage) of the peltier. Mating a water system and a peltier is nothing new to overclocking by any means. The peltier's cold side is used to chill the processor core and the hot side of the processor is cooled by the water system. This mating usually arrives at the best temperatures.

Anytime that you reduce the temperature of an object below the surrounding air (Ambient in most cases), the colder object will experience the formation of condensation. Condensation is also not a new experience for overclockers who have used some form of extreme cooling. Condensation is usually reduced and in some cases eliminated by the proper application of insulation. Most extreme cooling enthusiasts have used rubber, foam, closed cell neoprene, and silicone as the basis for their insulation elements.

A water cooled peltier works so effectively because the water system is able to drain the heat away from the hot side before the peltier can experience heat soakback. The cooler you keep the hot side the more effective the cold side becomes.

This is where my modification is different. I have used no foam or insulation barrier around the peltier, and a minimal amount of foam on the back of the motherboard.

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