Design and optimization of a holographic concentrator for two-color PV-operation

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:201318

Wagemann, E U; Froehlich, K; Schulat, J; Schuette, H; Stojanoff, C G ^[1]

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1. Technical Univ. of Aachen (Germany). Lehr- und Forschungsgebiet Hochtemperaturthermodynamik

The subject matter of this research project is to develop, manufacture and field test a spectrally dispersing solar collector system using a holographic solar concentrator in conjunction with spectrally matched advanced solar cells for photovoltaic power generation. The advantage of a holographic solar concentrator as compared to a conventional one is seen in the overall reduction of investment cost and in the possibility to generate inexpensive solar electric power. In this paper the authors present the techniques specifically developed for the design and manufacturing of efficient holographic optical elements and holographic lens stacks that are used in the fabrication of bandwidth matched solar concentrators for VIS and NIR photovoltaic operation. The lens stack separates the white light radiation into several spectral ranges that are focused onto photocells possessing corresponding spectral characteristics. Contrary to previously published arrangements, the authors present here the concept and the design characteristics of a holographic concentrator that allows positioning of the cells in a plane parallel to the lens aperture. The initial idea of using two lenses recorded in the same aperture or same holographic layer focusing onto two off-axis foci proved to be of limited value due to the off-axis focusing that introduces strong reflection and aberration. Here the authors present a new concept in which the two lenses are shifted in the plane of the aperture so that each lens-cell configuration exhibits axial geometry. Stack layouts for AlGaAs/GaAs and GaAs/Si combinations are discussed. Cross-coupling effects and aberrations involving the IR lens are minimized. Experimental diffraction efficiencies are fitted with non-cosinusoidal refractive index modulation showing best performance for 100 by 100 mm{sup 2} aperture. The theoretical predictions are compared with the first experimental results.

• OSTI ID: 201318
• Report Number(s): CONF-930722--; ISBN 0-8194-1266-X
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
ALUMINIUM ARSENIDES
CONCENTRATOR SOLAR CELLS
DESIGN
ENERGY EFFICIENCY
GALLIUM ARSENIDES
HOLOGRAPHY
NEAR INFRARED RADIATION
OPTICAL SYSTEMS
PERFORMANCE
PHOTOVOLTAIC POWER SUPPLIES
VISIBLE RADIATION