DIRECTLY Converting heat to electricity using compact, microfabricated thermionic devices.


team:

Daniel Riley, Ph.D. and Jared Schwede, Ph.D.

Daniel Riley, Ph.D. and Jared Schwede, Ph.D.

Jared Schwede and Daniel Riley completed their Ph.D.s in the department of physics at Stanford University. At Stanford, they were part of a world-leading research group on thermionic energy converters, focusing on a breakthrough solar conversion process based on photon-enhanced thermionic energy conversion, which harvests both photon and heat energy from the sun's spectrum.
 
Dan and Jared's work on thermionics has been recognized with the Ross N. Tucker Award, which acknowledges excellence in semiconductor and materials research, at the Berkeley Energy and Resources Collaborative Innovation Expo, and by the Global Climate and Energy Project, among others. They are excited to be leading this effort at Cyclotron Road to develop transformative thermionics technology. 


technology:

Critical need: Today, mechanical heat engines tower above all other methods of energy conversion. They transport us, keep us cool, and produce over 80% of US electricity. Nonetheless, these engines, born in 19th century technology, are constrained to applications that can tolerate their size and weight.

 
Source: JC Zhao, Adapted from Catalog of CHP Technologies, US Environmental Protection Agency Combined Heat and Power Partnership (2008)

Source: JC Zhao, Adapted from Catalog of CHP Technologies, US Environmental Protection Agency Combined Heat and Power Partnership (2008)

 

Technology vision: Thermionic energy converters can rival the performance of all conventional heat engines in a package that can be scaled from watts to megawatts. 

Current state-of-the-art: Thermionic energy converters have a very simple architecture based on two materials separated by a thermally insulating vacuum gap. These devices saw substantial development in the 1950's and 1960's, but were limited by the technologies of the day.

 
Hand-built research converters from GE Research, 1960s

Hand-built research converters from GE Research, 1960s

 

Key innovation: Applying modern materials and wafer fabrication techniques, Spark Thermionics will tap the full potential of thermionic conversion and transform how we harvest heat energy.

 
Microfabricated converter heated >1000°C at Stanford University, 2010s

Microfabricated converter heated >1000°C at Stanford University, 2010s

 

Manufacturing challenges: Wafer-scale microfabrication of vacuum devices, nanoscale surface engineering, and high-temperature encapsulation. 

Competing technology: Current practice for directly converting heat to electricity relies on thermoelectric devices, which use thermal gradients within solid-state materials to drive electric current. However, thermoelectrics are limited by parasitic heat losses intrinsic to the solid-state technology itself. The fundamental advantage of thermionic conversion lies in the vacuum gap architecture, a nearly perfect thermal insulator that allows enormous temperature differences between the hot and cool electrodes.

First market hypothesis: Thermionics will enable economic combined-heat-and-power systems for distributed power and high-temperature industrial processes, because they are able to operate efficiently at extremely high temperatures.

Potential for impact: Thermionics has the potential to dramatically increase our utilization of waste heat, harvesting energy that is inaccessible to conventional heat engines. Ultimately, thermionic energy conversion could even displace conventional engines and redefine the energy industry. 

We're looking for: 

  • Technical collaborators
  • Technoeconomic analysis 
  • Team members - scientists, engineers
  • Team members - business
  • Interns
  • Funders
  • Joint development partners

Links:

Previous work on related thermionics technology for solar applications: 

http://www.nature.com/nmat/journal/v9/n9/full/nmat2814.html

http://www.nature.com/ncomms/journal/v4/n3/full/ncomms2577.html

Press:

https://www.whitehouse.gov/blog/2015/10/14/progress-administrations-clean-energy-investment-initiative

http://www.sciencedaily.com/releases/2010/08/100802101813.htm

http://phys.org/news/2013-03-materials-scientists-solar-energy-chip.html

Contact: jschwede [at] lbl [dot] gov and dcriley [at] lbl [dot] gov


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