Table Of ContentWindow-Integrated Low Concentration Planar Light Guide Solar Concentrators
by
Daniel James Lawler Williams
Submitted in Partial Fulfillment of the
Requirements for the Degree
Doctor of Philosophy
Supervised by Professor Duncan T. Moore
The Institute of Optics
Arts, Sciences and Engineering
Edmund A. Hajim School of Engineering and Applied Sciences
University of Rochester
Rochester, NY
2016
ii
Biographical Sketch
Daniel Williams was born in Newark, Delaware. He attended the University o f Nebraska –
Lincoln and graduated with distinction, receiving a Bachelor of Science degree in both Physics
and Mathematics. He was awarded the Summer Undergraduate Research Fellowship by the
National Institute of Standards and Technology in 2006. He continued his education at The
Institute of Optics, University of Rochester. During graduate studies he was awarded the
Integrative Graduate Education and Research Traineeship by the National Science Foundation in
2010. He received a Master of Technical Entrepreneurship and Management degree, a joint
degree of the Simon School of Business and Hajim School of Engineering and Applied Science in
2012 and a Master of Science degree in Optics from The Institute of Optics in 2014. He pursued
his research in Optics under the direction of Professor Duncan T. Moore.
The following publications were a result of the work conducted during this doctoral study:
Yang Zhao, Daniel J. L. Williams, Peter McCarthy, et al., "Chromatic correction for a VIS -SWIR
zoom lens using optical glasses", Proceedings of SPIE Vol. 9580, 95800E (2015)
Anthony J. Yee, Daniel J. L. Williams, Gustavo A. Gandara-Montano, et al., "New tools for finding
first-order zoom lens solutions and the analysis of zoom lenses during the design
process", Proceedings of SPIE Vol. 9580, 958006 (2015)
Peter McCarthy, Rebecca Berman, Daniel J. L. Williams, et al., "Optical design study in the 1 -5μm
spectral band with gradient-index materials", Proceedings of SPIE Vol. 9293, 92930X
(2015)
Berman, Rebecca, et al. "Optical design study of a VIS-SWIR 3X zoom lens." SPIE Optical
Engineering+ Applications. International Society for Optics and Photonics, 2015.
iii
Acknowledgements
I would like to thank my advisor, Duncan Moore, for his academic guidance and
foresight in preparing me for post-graduate life.
I would like to thank Blair Unger, Eric Christensen, and Mick Brown for their
indispensable mentorship and their work in the Moore group that made my research possible.
I would like to thank Greg Schmidt for his selflessness and absolute willingness to help
his colleagues and share his broad range of knowledge.
I would like to thank my colleagues, Rebecca Berman, Anthony Yee, and Yang Zhao for
making our office a great and friendly place to work.
I would like to thank Per Adamson for his help on numerous occasions and his incredible
drive to help the students of The Institute of Optics.
I would like to thank Lynn Doescher and Evelyn Sheffer for their support of the Moore
group and for bringing a caring atmosphere to our offices.
I would like to thank my parents, John and Kathleen, for their consistent support and
interest in my work both during and prior to my graduate studies.
I would like to thank my parents-in-law for supporting me and my wife and welcoming
me into their family.
I would like to thank my friends, especially Zack Lapin, Richard Smith, Nicole Kendrot,
and Greg Schmidt for making life outside of research so much more enjoyable.
Finally, I would like to thank my amazing wife and best friend, Jennifer Muniak, for her
incredible support and encouragement during my graduate studies, and for bringing our
wonderful daughter, Penelope, into this world.
iv
Abstract
Several novel low concentration solar concentrator photovoltaic designs are presented,
based on the planar light guide architecture pioneered by the University of Rochester. These
systems are designed for integration into windows, requiring them to be stationary and to have
a large acceptance angle since they cannot move to track the sun. The application goal is to use
solar generated electricity to offset the energy lost through the window during cold times of the
year. The systems are evaluated for their effective insulation properties given the calculated net
energy lost. Without moving parts, they optimize to have acceptance angles of about 20° to 35°
in the vertical direction and ±90° in the horizontal direction, but have peak optical efficiencies of
less than 50%. By including internally moving parts, the acceptance angle is increased to nearly
a full π steradians (the full sky from the point of view of the window) and the average optical
efficiency increases to over 50%. Systems in certain locations are not viable due to low solar
irradiance in the wintertime, e.g., Rochester, NY. Others, however, reduce net energy loss to
zero for much of the year. A prototype of one of the systems is fabricated, measured, and
modeled. The simulated and measured performance data are compared and are in close
agreement, validating the model and the evaluation methods used during system optimization.
v
Contributors and Funding Sources
This work was supervised by a dissertation committee consisting of Professors Duncan
Moore, James Zavislan, and Julie Bentley of the Institute of Optics and Matthew Yates of the
Chemical Engineering Department at the University of Rochester. The initial design work was
funded by Rambus International Ltd. under Award Number – 056105-002. Additional funding
was provided by the National Science Foundation under the Integrative Graduate Education
Research and Traineeship (IGERT) program and L-3 Communications.
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Table of Contents
Biographical Sketch ......................................................................................................................................... ii
Acknowledgements ........................................................................................................................................ iii
Abstract .......................................................................................................................................................... iv
Contributors and Funding Sources .................................................................................................................. v
List of Tables ................................................................................................................................................. viii
List of Figures .................................................................................................................................................. ix
Chapter 1: Background ................................................................................................................................ 1
1.1 Solar Power ...................................................................................................................... 1
1.2 Concentrating Photovoltaics (CPV) .................................................................................. 2
1.3 Concentrator Design Theory .......................................................................................... 13
1.4 Low Concentration Photovoltaics .................................................................................. 18
1.5 Examples of Existing Low Concentration Systems ......................................................... 24
1.6 Examples of Non-Concentrating BIPV ............................................................................ 29
1.7 Window Integrated LCPV Planar Light Guide Solar Concentrators ................................ 30
Chapter 2: Design ...................................................................................................................................... 31
2.1 Application ..................................................................................................................... 31
2.2 The Louver Concept ....................................................................................................... 35
2.3 Optimization and Results ............................................................................................... 39
2.4 Analysis .......................................................................................................................... 49
2.5 Conclusion ...................................................................................................................... 63
Chapter 3: Prototype and Metrology ........................................................................................................ 65
3.1 Prototype ....................................................................................................................... 65
vii
3.2 Fabrication Methods ...................................................................................................... 69
3.3 Metrology Tools ............................................................................................................. 80
Chapter 4: Measurements and Computer Model ................................................................................... 100
4.1 Component Measurements ......................................................................................... 100
4.2 Performance ................................................................................................................ 121
4.3 Conclusion .................................................................................................................... 137
Chapter 5: Conclusion ............................................................................................................................. 138
5.1 Summary ...................................................................................................................... 138
5.2 Future Work ................................................................................................................. 139
References ................................................................................................................................................... 141
Appendix A. Design Specifications ......................................................................................................... 148
Appendix B. Deflectometer MATLAB Code ........................................................................................... 156
Appendix C. Optimization Routine MATLAB Code ................................................................................ 261
viii
List of Tables
Table 2-1: Thermal conductivities for various materials [26]. ...................................................................... 54
Table 2-2: Vertical angle field of view summary. The left data column indicates the vertical angle field of
view range for each design, the center column shows the average optical efficiency over that range,
and the right column gives the peak optical efficiency. ...................................................................... 63
Table 4-1: Guide layer designed vs. measured dimensions. ...................................................................... 100
Table 4-2: Injection prism designed vs. measured dimensions. ................................................................. 106
Table 4-3: Light I-V curve parameters for both PV cells. ............................................................................ 121
Table 4-4: Summary of simulated manufacturing flaws. The flaws are added to the model in the order
shown. ............................................................................................................................................... 124
ix
List of Figures
Figure 1.1: Residential silicon flat panel PV solar installation (top) and the Solucar PS10 solar thermal
power plant near Seville, Spain (bottom, [55], originally posted to Flickr by afloresm at
http://flickr.com/photos/
x
solid vertical lines represent the sun’s path for the first day of each month from Jan 1 to June 1 from
left to right, and the dashed lines do the same for July 1 to Dec 1 from right to left, and the blue
ellipse represents the eight hours per day boundary. ......................................................................... 19
Figure 1.11: Compound parabolic concentrator profile illustrating the edge ray principle. The blue rays
come from the edge of the source and focus to a point on the edge of the dark red target surface.
The red rays come from inside the edges of the source. .................................................................... 22
Figure 1.12: Direction cosine representation of the sun's position for eight hours per day, year round (grey
shaded area) and the fields of view of trough CPCs with an index of 1 (red ellipse) and 1.5 (blue
ellipse) that are just wide enough to capture sunlight for eight hours every day without tracking. .. 23
Figure 1.13: tenKsolar's RAIS™ PV system. The deep blue colored rows are silicon solar panels and the
translucent plates are cold mirrors that concentrate convertible sunlight onto the PV cells. [16] .... 25
Figure 1.14: See-through window CPV system schematic (top) and picture of prototype (bottom, [17]). . 26
Figure 1.15: Reproduced rendering of Stellaris' window CPV module showing extruded CPC troughs [18].
............................................................................................................................................................. 26
Figure 1.16: Reproduction from [21]. A schematic for a LSC showing the incoming sunlight, a luminescent
particle (orange circle), and re-emitted light that is lost (1) and trapped in the light guide (2). ......... 27
Figure 1.17: Luminescent concentrator plates. Image courtesy Fraunhofer ISE. ........................................ 28
Figure 1.18: Prism solar BIPV modules integrated into balcony railings [22]. .............................................. 29
Figure 2.1: LCPV field of view coordinate system definition. ....................................................................... 33
Figure 2.2: Map of sun's position in azimuth and elevation for Rochester, NY (latitude = 43.12°). Yellow
dots indicate sun position at various times. The black dashed lines indicate constant vertical angle.
............................................................................................................................................................. 33
Figure 2.3: Weighting functions for three cities in the U.S. ......................................................................... 34
Figure 2.4: Shadowing advantage of the louver design space, where part of the louver (a) is designed for
greater vertical angles and other parts (b) are optimized for lesser ones. ......................................... 36
