Journal of Solar Energy Engineering
Analysis of Potential Conversion Efficiency of a Solar
Hybrid System With High-Temperature Stage
J. Sol. Energy Eng. -- May 2006 --
Volume 128, Issue 2, 258 (3 pages)
http://dx.doi.org/10.1115/1.2189865
http://dx.doi.org/10.1115/1.2189865
Author(s):
Y. V. Vorobiev
CINVESTAV-Querétaro, Libramiento Norponiente 2000, Querétaro 76230, QRO, México
J. González-Hernández
CIMAV, Miguel de Cervantes 120, Chihuahua 31109, México
A. Kribus
Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
Y. V. Vorobiev
CINVESTAV-Querétaro, Libramiento Norponiente 2000, Querétaro 76230, QRO, México
J. González-Hernández
CIMAV, Miguel de Cervantes 120, Chihuahua 31109, México
A. Kribus
Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
The analysis is given of hybrid system of solar energy
conversion having a stage operating at high temperature. The
system contains a radiation concentrator, a photovoltaic solar
cell, and a thermal generator, which could be thermoelectric
one or a heat engine. Two options are discussed, one (a) with
concentration of the whole solar radiation on the PV cell
working at hightemperature and coupled to the high-temperature stage, and
another (b) with a special PV cell construction, which allows
the use of the part of solar spectrum not absorbed in the semiconductor
material of the cell ("thermal energy") to drive the high-temperature
stage while the cell is working at ambient temperature. The
possibilities of using different semiconductor materials are analyzed. It is
shown that the demands to the cell material aredifferent in the two cases
examined: in system (a) with high temperature of cell
operation, the materials providing minimum temperature dependence
of the conversion efficiency are necessary, for another system (b)
the materials with the larger band gap are profitable. The
efficiency of thermal generator is assumed to be proportional to
that of the Carnot engine. The optical and thermal energy
losses are taken into account, including the losses byconvection and radiation
in the high-temperature stage. The radiation lossesimpose restrictions upon the
working temperature of the thermal generator in the system (b),
thus defining the highest possible concentration ratio. The
calculations made show that the hybrid system proposed could be
both efficient and practical, promising the total conversion efficiency
around 25–30 % for system (a), and 30–40 % for system (b).
©2006 American
Society of Mechanical Engineers
History:
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Received 20 September 2005; revised 30 September 2005
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