Concentrator PV modules and solar cells for TPV systems

Concentrator technology is considered as a lower cost alternative to the “flat” solar arrays. For high concentration ratios (500× and higher) the use of high-efficiency III–V solar cells is very promising and can provide reduced cell cost contribution to the cost of an installation. The efficiencies of 25–27% were achieved for the single-junction AlGaAs/GaAs solar cells under 500–1500 suns, AM1.5d. These cells are applied in the concentrator modules based on a concept of the small-aperture refractive concentrators. A modified structure of the high concentration “all-glass” PV modules with III–V solar cells is proposed. In the “all-glass” module design, the secondary small-aperture smooth surface lenses arranged in an intermediate composite (glass–silicone) panel be inserted between a panel of the primary composite Fresnel lens concentrators and a panel of the solar cells. Such a design allows fabricating the modules of large total area (up to 0.5×1 m2) and improving environmental protection of the cells. The cells as small as 1.2 mm in designated area diameter operating at very high concentration ratio (more than 1000×) can be used in the developed solar PV modules. Also, solar thermophotovoltaics (TPV) is discussed and results of the narrow-gap GaSb and GaAs/Ge cell development for TPV receivers are presented.