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Method for the addition of surfactants to heat pipes for reducing evaporation resistance

IP.com Disclosure Number: IPCOM000029137D
Publication Date: 2004-Jun-16
Document File: 2 page(s) / 49K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for the addition of surfactants to heat pipes for reducing evaporation resistance. Benefits include improved performance.

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Method for the addition of surfactants to heat pipes for reducing evaporation resistance

Disclosed is a method for the addition of surfactants to heat pipes for reducing evaporation resistance. Benefits include improved performance.

Background

              Conventionally, heat-pipe technology is used to cool notebook (NB) computers. Heat pipes carry heat from heat-generating devices, such as a central processing unit (CPU), to a remote heat exchanger. However, the pipes are constrained by relatively high resistance at the interface with the heat generating device, such as the CPU. This resistance occurs as a result of a combination of resistance in conducting the heat to the water and resistance in boiling the fluid (wall super heat).

              Adding ~200-300 ppm of surfactants reduces the wall super heat requirement for boiling by a factor of ~5 due to significantly reduce the surface tension of water. As a result, lesser force is required for forming and departing a bubble from the wall, which directly results in lower evaporative resistance.

              Several different types of surfactants exist, such as cationic, anionic, and non-ionic, which could be used. The disclosed method requires a surfactant that is water soluble and has excellent stability to last for several years.

              One issue is that the very phenomena that reduces the evaporation resistance (reduction in surface tension) decreases the pumping capacity of the wick. However, adding 200 ppm of surfacta...