Direct Conversion of Nanoscale Thermal Radiation to Electrical Energy Using Pyroelectric Materials

Tech ID: 22144 / UC Case 2010-532-0

Summary

UCLA researchers have developed a novel way to harvest waste heat by combining thermal radiation at the nanoscale with pyroelectric energy conversion.

Background

Rising awareness in sustainable and efficient energy technologies has stimulated efforts in harvesting energy that would otherwise be wasted. A pyroelectric energy converter offers the prospect of directly transforming waste heat into electricity. However, the operating frequency of such a device is usually small (~0.1 Hz), and limited by convective heat transfer between the pyroelectric material and the working fluid’s oscillations, which restrict the performance of the device. However, thermal radiative heat transfer is exchanged at the speed of light, and has the potential to increase the operating frequency of pyroelectric energy converters, resulting in significantly better power density and efficiency.

Innovation

UCLA researchers in the Department of Mechanical Engineering have developed a new technology that combines nanoscale radiative heat transfer and pyroelectric energy conversion in a single device to harvest waste heat with large power output and energy efficiency. The device consists of bringing the pyroelectric element in close proximity successively with a hot surface and with a cold surface while performing the Olsen cycle. Displacement can be achieved using low power piezoelectric actuators, for example. The proposed technology is relatively simple to setup and microfabricate.

Applications

• Harvest low grade waste heat energy and convert it to usable electricity.

o Heat from cell phones
o Heat from CPUs
o Heat from industrial processes
o Heat from chemical processes

Advantages

  • Can operate at low temperatures (< 100°C). Depending on the need, the pyroelectric materials can be selected to operate at higher temperatures 
  • Use near field effects to enhance radiative heat transfer between the pyroelectric element and the hot and cold sources.
  • Can operate at larger frequency and achieve larger power densities than other pyroelectric devices based on the Olsen cycle.

State Of Development

The invention is conceptual and simulations have shown its feasibility. Experiments have established radiative heat transfer enhancement between surfaces in close proximity. 

Patent Status

Country Type Number Dated Case
United States Of America Published Application 20110298333 12/08/2011 2010-532
 

Contact

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Inventors

  • Pilon, Laurent G.

Other Information

Keywords

pyroelectric effect, ferroelectric, direct energy conversion, nanoscale thermal radiation, waste heat harvesting, direct energy conversion, CleanTech

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