Location-Specific Spectral and Thermal Effects in Tracking and Fixed Tilt Photovoltaic Systems.

The efficiency of photovoltaic modules in the field is generally lower than the efficiency under standard testing conditions due to temperature and spectral effects. Using the latest spectral dataset available from the National Solar Radiation Database, we report spectral correction factors ranging from -2% to 1.3% of the produced energy for silicon modules depending on location and collector geometry.

Performance of a dielectric PVT concentrator for building-façade integration.

Concentrating photovoltaic-thermal (CPVT) systems, which can be integrated on buildings façades and use low-accuracy trackers and standard cells, have the potential to produce cost-effective electricity and heat. In this paper, a refractive cylindrical CPVT module with cells directly immersed in deionized water (DIW) or isopropyl alcohol (IPA) is designed, fabricated and experimentally tested. The interfaces between the cylinder and the fluids cavity have been optimized to maximize optical efficiency and irradiance uniformity, obtaining better results for a geometric concentration of 10x and IPA.

Full modeling and experimental validation of cylindrical holographic lenses recorded in Bayfol HX photopolymer and partly operating in the transition regime for solar concentration.

Concentrating photovoltaics for building integration can be successfully carried out with Holographic Optical Elements (HOEs) because of their behavior analogous to refractive optical elements and their tuning ability to the spectral range that the photovoltaic (PV) cell is sensitive to. That way, concentration of spectral ranges that would cause overheating of the cell is avoided. Volume HOEs are usually chosen because they provide high efficiencies.

Characterization of volume holographic optical elements recorded in Bayfol HX photopolymer for solar photovoltaic applications.

Volume Holographic Optical Elements (HOEs) present interesting characteristics for photovoltaic applications as they can select spectrum for concentrating the target bandwidth and avoiding non-desired wavelengths, which can cause the decrease of the performance on the cell, for instance by overheating it. Volume HOEs have been recorded on Bayfol HX photopolymer to test the suitability of this material for solar concentrating photovoltaic systems. The HOEs were recorded at 532 nm and provided a dynamic range, reaching close to 100% efficiency at 800 nm.

Broadband behavior of transmission volume holographic optical elements for solar concentration.

A ray tracing algorithm is developed to analyze the energy performance of transmission and phase volume holographic lenses that operate with broadband illumination. The agreement between the experimental data and the theoretical treatment has been tested. The model has been applied to analyze the optimum recording geometry for solar concentration applications.