Page 116 - ISES SWC50

Lorin Vant-Hull
Country: United States
Year Started Research: 1972
Title of Research: Solar Thermal Power Systems based on Optical
Transmission --Solar Tower or Central Receiver
University: University of Houston
Still Active in Research: Yes

Professor Vant-Hull was Principal Investigator on the first modern feasibility study of the central receiver concept.
This involves the optical transmission of sunlight reflected from thousands of large mirrors (30-100 sq m), which
are tracked to concentrate the sunlight onto an elevated central receiver. With a concentration of over 1000 suns,
energy is absorbed and efficiently transferred to a working fluid at 500 to 800+ deg C. Typically, molten salt is
used so the hot fluid remains at atmospheric temperature and can conveniently be stored in a hot and a warm tank.
When needed, hot salt is heat exchanged to generate steam suitable for a utility scale turbine and dispatchable
electricity is provided to the grid. Vant-Hull was responsible for the development of computer codes which provided
sun positions, solar intensity, cosine effects on the heliostats, shading and blocking of heliostats, and solar flux
density distributions on the receiver. After noting that radial arrays performed best, the radial-stagger configuration
was developed to minimize S&B effects. With support from MacDonnell Douglas, we also developed appropriate
cost models including variation with appropriate parameters such as tower height, power level, receiver size, etc.
allowing for detailed cost-effective optimization of the system. Thus, the external receiver with a surround field is
found to perform better on an annual basis than any flat plate or cavity receiver. He provided design assistance
to most of the major players in the 1980-2010 time frame and has served on numerous NSF, Sandia, NREL, and
DOE proposal review panels and program reviews. In addition, he was selected to participate in President Carter’s
Scientist Exchange program with Russia. Vant-Hull has also been an associate Editor of the Journal of Solar Energy
since 1974 and has authored numerous peer-reviewed papers, innumerable proceedings papers and progress
reports, has authored four book chapters, and is co-editor on one of the books.

Sudhanshu Varma

Country: Canada
Year Started Research: 1975
Title of Research: Development of Schottky Barrier / MOS Solar Cells
University: Indian Institute of Technology - Kanpur, India
Still Active in Research: No

Dr. Sudhanshu Varma is a Materials Scientist with specialization in fabrication and characterization of semiconductor
materials and devices for solar cell applications. He has been involved in the solar photovoltaic field for the past
45 years. He started solar cell research at the Indian Institute of Technology, Kanpur in India in 1975 during his
M. Tech. program. His initial research was aimed at fabrication and characterization of thin films, and Schottky
Barrier / MOS solar cells. Over the next eight years, he diversified his research at IIT Kanpur to include fabrication
and characterization of p-n homojunction and heterojunction solar cells, studying the performance of solar cells
under concentration, and deposition and characterization of Tin Oxide and Indium Tin Oxide antireflection coatings
and transparent-conductor-oxide-semiconductor surface barrier devices (solar cells) - which led to his Ph. D. in
Materials Science. Dr. Varma transitioned to solar industry in India in 1983 by joining Central Electronics Ltd, where
he got involved in solar module production technology, solar module testing and managing commercial solar module
production. He moved to Canada in 1984 and joined TPK Solar Systems in Ottawa where he became involved
in the development of commercial p-n junction silicon solar cells and solar module manufacturing technologies,
commercial production of solar modules, and international technology transfer while setting up turnkey production
lines for customers in different countries. He also conducted research on screen printed antireflection coatings as
well as screen printed diffusion sources aimed at developing manufacturing technology for all screen printed solar
cells. Moreover, he became involved in the development of customized solar cell and module manufacturing and
testing equipment. He also conducted research on spray deposition of antireflection coatings and diffusion sources.

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