Physicists Look to Turn Heat into Sound into Electricity

According to a University of Utah report, this new method of creating electricity will help cool laptops and other electronic devices.

A group of University of Utah physicists are working on a way to convert heat into sound and then into electricity, which could open the door for better ways to cool laptops and other electronic devices and could potentially ease the power crunch in data centers.

The team of researchers, led by Orest Symko, a physics professor at the University of Utah, is scheduled to detail their findings at the Acoustical Society of America conference in Salt Lake City June 8, according to a statement issued by the school.

Symkos team will divulge how they were able to develop small acoustic heat-engine devices that turn heat into electricity. The group plans to test the devices in about a year and will try to convert waste heat generated from a military radar facility and a hot-water generating plant into electricity.

While these developments have potential use in a number of fields, within the IT space, the devices could be used to cool laptops and desktops. A key to the IT field is getting these converter devices small enough to incorporate into MEMS, or microelectromechanical systems—machines so small that they can not be seen with the naked eye—for eventual use in PCs and other electronic devices.

The report did not indicate if or when this would be possible. Within two years, Symko reported, these devices could be used as an alternative to photovoltaic cells for converting sunlight into electricity.

The idea of offering devices that use less power, while offering better performance, is an idea that several OEMs have pursued. For example, both Intel and Advanced Micro Devices—the worlds two largest producers of microprocessors—each offer chips that provide better performance per watt or how much power each chip consumes versus the amount of performance it offers customers.

/zimages/3/28571.gifClick here to read more about what Intel and AMD have in store for better performing chips.

On the other side, PC makers like Dell and Hewlett-Packard are offering business desktops that adhere to the new Energy Star 4.0 standards developed by the U.S. Environmental Protection Agency. When these standards go into effect July 20, they will call for 80 percent efficient power supplies and lower idle wattage ratings.

The work that the chip makers and OEMs are doing not only are aimed at making devices run cooler, but also at helping enterprises that are seeing temperatures and power costs rising in their data centers.

The devices that Symko and his team are developing use two specific steps to convert sound into heat and then into electricity.

The first step involves converting heat into sound using newly developed heat engines called "thermoacoustic prime movers." Then, the process requires that sound be converted into electricity using an existing technology dubbed "piezoelectric," which are devices that are squeezed in response to pressure – including sound waves – and change that pressure into an electrical current.

In the lab, these devices are housed in cylinder-shaped resonators. Each cylinder contains a large amount of material with a large surface area – these materials can be plastic or metal plates or glass, cotton or steel wool fibers—that are placed between a cold heat exchanger and a hot heat exchanger.

/zimages/3/28571.gifClick here to read more about the greening of the data center.

When heat is applied, it builds to a threshold. Then the hot, moving air produces sound at a single frequency. The sound waves are then squeezed in the piezoelectric device, which produces the electrical voltage, according to a summary of the report.

This research, according to the University of Utah, has been funded with help by the U.S. Army.

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