Researchers at the University of Arizona have designed a hybrid solar collection and distribution system to optimize the use of the solar collector footprint as well as the solar spectrum. The system splits the spectrum into two components to distribute the peak wavelengths for algae growth, PV, and thermal uses. Algae responds best to photosynthesis wavelengths (400-700 nm) whereas photovoltaic cells and thermal collectors respond well to different and broader spectral ranges. In the UArizona design, one wavelength band is focused by a holographic lens through a mirror aperture onto a ground target, landing uniformly within the shadow of the mirror. The rest of the spectrum passes through the lens, reflects off of the mirror, and lands on the thermal or photovoltaic receiver. The design accommodates four different geometries, including thermal mirror arrays and photovoltaic arrays, so is versatile in its applicability.
Background:
With the increased interest in biofuels, such as algae, and in efficient use of solar radiation collectors, a need exists to optimize the energy efficiencies of the ground footprint. Several designs currently exist to spread the solar spectrum for optimization of PV conversion to electricity, but they don't address thermal conversion or biofuel needs. Biofuels such as algae exhibit better growth if they are protected from portions of solar radiation outside of the photosynthesis band of 400nm to 700nm. Thermal needs can tap a different broad portion of the solar spectrum than PV. Solar collectors, for PV or thermal, and algae farms take up large footprints of real estate. The most efficient method of solar-based energy production would utilize one footprint for all three forms of solar-based energy production. The design by the UArizona researchers not only provides a means of using one footprint for collecting light for all forms, but optimizes the algae production as well as the thermal or photovoltaic conversion efficiencies.
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Status: issued U.S. patent #10,514,485