KEYWORDS: Silicon, Solar energy, Data modeling, Solar radiation models, Concentrated solar cells, Thermal modeling, Performance modeling, Atmospheric modeling, Gallium, Solar cells
Conventional concentrator photovoltaics (CPV) employing two-axis tracking are generally only economically competitive with cheaper, less efficient alternatives in locations with large amounts of direct sunlight. Adding a diffuse light collector to a CPV panel in the form of a silicon back panel can potentially improve the light collection under cloudy conditions and expand the range of climates in which CPV is useful. However, to understand the performance advantages available with diffuse collection, a realistic forecasting tool to predict performance in different locations is required. We introduce a model to evaluate the annual energy yield of a hybrid CPV and Si module and compare the results with several conventional stand-alone Si and CPV modules. The advantages of including a bifacial Si panel as the diffuse collector will also be investigated.
In this paper, we present findings on micro-concentrator photovoltaic cells composed of lattice matched subcells grown on GaAs and InP substrates, which are stacked into single, four-terminal devices using micro-transfer printing. The design, modeling, growth, fabrication and assembly of the devices will be described, and potential interconnection schemes to achieve efficient, two-terminal strings of cells with flexible current and voltage outputs and resilience to defects is discussed.
KEYWORDS: Solar cells, Composites, Silicon, Monte Carlo methods, Concentrated solar cells, Brain-machine interfaces, Resistance, Reliability, Gallium arsenide, Glasses
One advantage of microconcentrator photovoltaics (μ-CPV) is the range of possible circuit connection arrangements. Large numbers of cells can be connected in combinations of series and parallel strings, which can provide a means to protect the module against performance loss due to cell failure, cell shading, and other variations in cell parameters that may arise during the fabrication and wiring processes. We introduce a model to evaluate the best strategy for optimizing module reliability through circuit layout using a combination of series and parallel connected cell strings. The model uses realistic solar cell device parameters in an electrical network simulation, coupled with a Monte Carlo method to introduce defects into the array with different probabilities. We use the model to optimize the layout of a μ-CPV panel designed to be integrated with the conventional 60-cell crystalline silicon panels for diffuse light capture to produce a hybrid direct/diffuse CPV product.
We experimentally demonstrate that the acoustic transients propagating as a result Free-Electron Laser (FEL) ablation
in brain tissue exhibit a strong FEL wavelength dependence. These acoustic transients were measured with a time-resolved,
polarization quadrature laser interferometer. The transients are multiphased, with displacements of tens of
microns and durations of tens of milliseconds. We calculated the Fourier transforms, power spectra, and pressure
transients based on these displacement data sets. For 3.0 μm irradiation, the bandwidth of the Fourier components
extends to ~20 kHz, while for 6.45 μm irradiation the bandwidth of the Fourier components extend to ~8 kHz. For the
3.0 μm irradiation, the power spectra indicate acoustic energy propagates in the bandwidth up to ~12 kHz, with
structure in the 1-4 kHz range. For the 6.45 μm radiation, the mechanical power spectra indicate the acoustic energy
propagates in the bandwidth up to ~7 kHz, with structure throughout. The pressure transients resulting from 3.0 μm
irradiation have a leading phase with a faster onset, shorter duration, and more than ten times the peak pressure
compared to that observed in pressure transients resulting from 6.45 μm irradiation. For 3.0 μm irradiation, the
observed pressure transients have peak pressures in the MPa range and durations of ~1 ms, while for 6.45 μm
irradiation the pressure transients have peak pressures in the 0.1 MPa range and durations of about ~3 ms.
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