Modeling and fabrication of high power density microscale thermophotovoltaic devices

There has been renewed interest over the past decade or two in the potential of using thermophotovoltaic (TPV) systems for direct conversion of thermal energy into electricity. The invention of TPV systems can be traced to almost 50 years ago, but systems developed over the following 2-3 decades lacked in efficiency and power density. Later on, the development of III-V materials with low bandgaps promised higher efficiency and power density, and renewed the research interest in TPV. More ideas emerged recently, including the use of two surfaces separated by nanometer scale spacing to exceed the vacuum blackbody limit, potentially realizing TPV systems with greater power density. A new microscale TPV device structure made of fin-shaped interdigitized emitters and photovoltaic cells offers an increase in the surface area available for radiative energy transfer, which could boost the output power density. In addition, if the spacing between the radiator and converter is of the order of a micron, tunneling of energy could occur, which can improve the power density. A periodic structure can recoup sub-bandgap radiation, since such radiation will pass through the converter and will be absorbed in the radiator, thereby improving efficiency of the device. Some of the above-bandgap photons that pass through the converter could also be recycled between emitters and photovoltaic cells. This thesis presents work done on modeling and fabricating an interdigitized microscale TPV device. The advantage in power density that can be obtained from an interdigitized TPV structure is estimated first by a bulk emissivity and view-factor based model, followed by a thin-film emissivity model. Calculations performed to estimate parameters such as power output, power input

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Shah, Ashish A., 1979-

Advisor dc:contributor.advisor

• Gang Chen.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/27114

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/27114