Keeping today's electronics cool isn't as easy as running a fan installed at the rear of a desktop computer. Using anything from a smartphone to an electric vehicle results in some manner of heat production that eventually leads to the deterioration of the device.

Amy Marconnet, professor of mechanical engineering at Purdue University, is researching today's wide range of technology to develop electronics cooling and thermal management techniques focusing on reducing the heat that's produced, potentially resulting in improved device power and usage.

Electronics have a narrow temperature range where they can function efficiently. In an ever-evolving era of technology, there are a variety of ways to keep devices cool, even at a nanoscale level.

"On the semiconductor side, we're mainly looking at improving thermal management to let electronics run at higher powers," Marconnet said. "With wearable electronics, there's tighter temperature controls required because it's directly in contact with people at all times or when it's in use and getting hot."

That requirement has resulted in researching materials that can better transfer the heat in a system away from where it is building up without adding additional weight or manufacturing costs to the device.

Marconnet said phase change materials are one option her research is delving into. The materials provide thermal management by absorbing or releasing heat during the transition between melting or solidifying, depending upon the conditions. They also are being researched for the power electronics in electric vehicles.

"So, you can have the materials be melting while you're, say, using your VR (virtual reality) goggles," she said. "And then when you're recharging your goggles or overnight, they will solidify, and you can use the device with higher intensity the next day."

By melting, the phase change materials absorb the heat being produced, while solidifying again releases the heat. Marconnet recently researched using a metallic alloy as a phase change material within a chip to keep the system compact, yet effective. This work was spearheaded by Marconnet's graduate student Meghavin Bhatasana.

Marconnet has published previous papers on thermal greases, a pastelike material that is put between a silicon chip and the heat-spreading components in the system.

Thermal greases eventually are "pumped out" of the area between the chips and other components, causing a device like a computer to drop in performance.

"We're trying to figure out a fast test method right now for identifying which materials will perform well and which will perform poorly without having to wait for a year or more of an actual use of the system," Marconnet said.

Thermal management also examines the part batteries play in heat buildup, especially as the demand increases for faster charges, particularly in electric vehicles.

Marconnet compared heat buildup from charging a device battery to the light from an incandescent light bulb. While you get useful light from the bulb, it also gets hot. When charging a battery, you also get useful power, but heat is generated by the battery's electrochemical reactions. So, while some of the power is being used for the chemical reactions that charge the battery, another portion of the power just gets wasted as heat in the device.

Marconnet and Xiulin Ruan, a professor in the School of Mechanical Engineering, already have worked to extend the life of devices by creating a compressible foam that can spread out heat building up as well as offer insulation against colder temperatures. The Purdue Innovates Office of Technology Commercialization has filed a patent application for it.

Two new papers regarding Marconnet's work on phase change materials have been submitted and are under review.