HIGH EFFICIENCY THERMOPHOTOVOLTAIC SYSTEMS. Anubha Mathur, Enas Said Sakr, Professor Peter Bermel Purdue University

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1 HIGH EFFICIENCY THERMOPHOTOVOLTAIC SYSTEMS Anubha Mathur, Enas Said Sakr, Professor Peter Bermel Purdue University

2 PRESENTATION OVERVIEW Motivation and Introduction Background Research and Methodology TPXsim : A System-Level Modelling Tool on nanohub.org Results, Conclusions and Future Work 2

3 WHY IS IT IMPORTANT? Too much parasitic loss in commonly used devices, like ovens and light bulbs Parasitic Losses in a TPV cell 61% of raw energy wasted in 2013! 3

4 WHAT IS THERMOPHOTOVOLTAIC TECHNOLOGY? Converts heat energy to electrical energy using thermal radiation to illuminate a PV diode Thermal Emitter + Filter + Photovoltaic Cell Radiation is generated by a blackbody-like emitter. Only higher energy photons can be converted by the PV diode, which severely limits efficiencies. Harvested photons Parasitic losses filter Typical PV bandgap 4

5 SOLAR THERMOPHOTOVOLTAICS Solar resource is large enough to meet future energy needs. Solar photovoltaics Solar thermophotovoltaics 5

6 PRESENTATION OVERVIEW Motivation and Introduction to Thermophotovoltaic Technology Background Research and Methodology TPXsim : A System-Level Modelling Tool on nanohub.org Results, Conclusions and Future Work 6

7 BACKGROUND RESEARCH Professor Bermel s research: Efficiency enhanced to 26.2% Retains more heat by adding a rugate filter Peter Bermel et al. (2010). Design and global optimization of high-efficiency thermophotovoltaic systems. Retrieved from Past research in MIT: Vertical-cavity enhanced resonant thermal emitter (VERTE) Enhanced thermal emittance to 100% near a cavity resonant frequency. Ivan Celanovic et al. (2005). Resonant-cavity enhanced thermal emission. Retrieved from Research by NASA: Spectral emittance model for films of rare earth-based materials Emits radiation in several narrow bands Donald L. Chubb et al. (1999). Rare Earth Doped High Temperature Ceramic Selective Emitters. Retrieved from Normal Emittance ~94% 7

8 WHAT S NEW? Concept of Chirped Dielectric mirrors: Limit emitted wavelengths Ensure unidirectional emission. Suppress parasitic losses Selective Emitter uses Q-matching, as in the VERTE structure ErAG used as the selective emitter, thanks to strong emission peaks in near-ir. 8

9 PHYSICS AND MATH PV current Dark Current Radiation Efficiency Average Emissivity 9

10 PRESENTATION OVERVIEW Motivation and Introduction to Thermophotovoltaic Technology Background Research and Methodology TPXsim : A System-Level Modelling Tool on nanohub.org Results, Conclusions and Future Work 10

11 WHAT IS NANOHUB? An open-access science gateway for cloud-based simulation tools and resources in nanoscale science and technology. Last 12 months Over 300k/year! 11

12 TPXSIM: A SYSTEM-LEVEL MODELING TOOL 12

13 PRESENTATION OVERVIEW Motivation and Introduction to Thermophotovoltaic Technology Background Research and Methodology TPXsim : A System-Level Modelling Tool on nanohub.org Results, Conclusions and Future Work 13

14 WHAT ARE THE BEST CASE EFFICIENCIES? Unprecedented Efficiency of 33.89% is achievable for a filter band gap of 0.37 ev and PV band gap of 0.75 ev Efficiency Emmisivity 0.8 Filter Bandgap Typical PV bandgap Wavelength(nm) PV Bandgap

15 CONCLUSIONS We have abundant waste heat and solar resources; can we use them with thermophotovoltaics? Blackbody emission severely limits TPV efficiencies; selective emission could greatly enhance performance We consider a rare earth-doped selective emitter with resonant enhancement and broadband filtering TPXsim, a system-level modeling tool on nanohub.org provides webenabled graphical interface to design and optimize this class of emitters Unprecedented system efficiencies of 34% achieved in simulations. 15

16 FUTURE WORK Further optimization using TPXsim Ongoing Research in Birck Nanotechnology center will use these predictions to experimentally fabricate and characterize these structures 16

17 REFERENCES PAPERS REVIEWED: Donald L. Chubb, a* AnnaMaria T. Pal, b Martin O. Patton b and Phillip P. Jenkins(1999, October). Rare Earth Doped High Temperature Ceramic Selective Emitters. Retrieved from Ivan Celanovic,* David Perreault, and John Kassakian (2005, August 19). Resonant-cavity enhanced thermal emission. Retrieved from Joannopoulos1,2,3,4, Steven G. Johnson1,6, Ivan Celanovic3(2010). Design and global optimization of highefficiency thermophotovoltaic systems. Retrieved from Bermel, P., Chan, W., Yeng, Y. X., Joannopoulis, J., Soljacic, M., & Celanovoic, I. Thermophotovoltaic Generation of Electricity.. Retrieved July 28, 2014, from WEBSITES VISITED: nanohub.org S4, web.stanford.edu Wikipedia.org, PV education SPECIAL THANKS: Zhiguang Zhou for reviewing the tool on nanohub SURF, Department of Electrical Engineering, Purdue University 17

18 Thank You! Any Questions? 18