Solar thermionic converter

Thermionic conversion of concentrated solar radiation at 800-1000°C, using innovative materials and heat recovery, can generate electricity and heat at high overall efficiencies.

Thermionic conversion uses high temperature thermal energy to drive electrons across a gap and thus creating an electrical current. A thermionic converter is a solid state device with no moving parts, with the main challenge being the high temperatures. We are developing a converter, based on advanced ceramic materials and surface coatings, that allows efficient electron emissions at temperatures below 1000°C (typically thermionic devices operate well above 1000°C). The thermionic emitter also serves as an absorber of concentrated solar radiation to provide heating. The thermionic converter is coupled to a second stage thermo-electric converter that uses ‘waste’ heat from the thermionic stage to produce additional electricity. The overall efficiency of this 2-stage design is expected to be around 35%. It is also possible to collect the low-grade heat rejected from the bottom of the thermo-electric converter at about 90°C and use it as an additional energy product in cogeneration mode. In this project we are developing the basic materials, coatings and processes necessary to create an efficient thermionic converter, constructing a demonstration device with both thermionic and thermo-electric stages, and testing the device in a solar furnace to validate its operation.

Collaboration with partners from Italy and Turkey

Support: European Commission, FP7