Researchers at San Diego State University in California are examining an alternative to traditional heat pipes they say could help increase cooling efficiency in laptops and other portable electronic devices.
Known as pulsating or oscillating heat pipes, the system may offer a heat transfer capacity up to 100 times better than conventional heat pipes, says assistant professor Gregory Michna of the SDSU Mechanical Engineering Department. This increased capacity could help alleviate the limits placed on component design by current thermal management techniques and enable implementation of smaller, more powerful devices.
According to Michna, pulsating heat pipes look much like an accordion, with a single tube looping up and down from the hot to the cool part of the device. The system does not require a wick structure and is partially filled with a working fluid such as water, alcohol or refrigerant. Used in combination with a heat sink, the fluid vaporizes when it absorbs heat in the hot section and then condenses as it releases heat in the cool portion.
When the temperature difference between the hot and cool ends exceeds a certain threshold, the fluid begins to oscillate in the thin tube. Thus, the passive system “doesn’t draw power,” Michna says, adding that the design’s simplicity increases its reliability and decreases its cost.
Together with graduate student Sagar Paudel of Nepal and undergraduate student Mitchell Hoesing of Jackson, Neb., Michna will examine the system’s operation during startup, what parameters affect its performance and how best to miniaturize the cooling portion to fit in a small heat sink. Two experimental devices—one large and one small—filled with water are being used for testing purposes.
The data gathered by the SDSU team will reportedly be used to strengthen an upcoming proposal to the National Science Foundation.
A one-year, $99,118 grant from the South Dakota Board of Regents was awarded for the project.
