Spectrally and angularly selective photothermal and photovoltaic converters under one-sun illumination

Bădescu, Viorel

doi:10.1088/0022-3727/38/13/014

Cited by 38 publications

(26 citation statements)

References 13 publications

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“…If emission at large angles can be confined, then the emittance will be reduced without affecting the absorptance. Even under only one sun illumination, directional selectivity has the potential to raise receiver efficiency levels to those of high concentration systems (Badescu, 2005;Blanco et al, 2004).…”

Section: Cavity Receiver Conceptmentioning

confidence: 99%

“…Another way to improve the performance of solar systems is to use directional selectivity, which allows sunlight to be absorbed in specific directions but suppresses IR emission in other directions (Badescu, 2005;Blanco et al, 2004;Boriskina and Chen, 2014;Florescu et al, 2007). This can be achieved with photonic crystals (Hamam et al, 2011;Shen et al, 2014), grooved surfaces (Hollands, 1963;Perlmutter and Howell, 1963), and optical cavities (Braun et al, 2013;Gordon et al, 2004;Luque and Araújo, 1990).…”

Section: Introductionmentioning

confidence: 99%

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Optical cavity for improved performance of solar receivers in solar-thermal systems

et al. 2014

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Abstract:A principal loss mechanism for solar receivers in solar-thermal systems is radiation from the absorbing surface. This loss can be reduced by using the concept of directional selectivity in which radiation is suppressed at angles larger than the incident angle of the sunlight striking the absorber. Directional selectivity can achieve efficiencies similar to high solar concentration, without the drawbacks associated with large heat fluxes. A specularly reflective hemispherical cavity placed over the absorber can reflect emitted radiation back to the absorber, effectively suppressing emission losses. An aperture in the cavity will still allow sunlight to reach the absorber surface when used with point focus concentrating systems. In this paper the reduction in radiative losses through the use of a hemispherical cavity is predicted using ray tracing simulations, and the effects of cavity size and absorber alignment are investigated. Simulated results are validated with proof of concept experiments that show reductions in radiative losses of more than 75% from a near blackbody absorber surface. The demonstrated cavity system is shown to be capable of achieving receiver efficiencies comparable to idealized spectrally selective absorbers across a wide range of operating temperatures. Highlights:-A specularly reflective cavity placed over a solar absorber reduces radiative losses -Cavity performance is sensitive to cavity size and cavity-absorber alignment -Radiative loss reduction validated with proof of concept experiments -Losses from near blackbody absorber reduced by over 75% -Receiver efficiency shown to be comparable to idealized wavelength selective absorber

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Section: Cavity Receiver Conceptmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optical cavity for improved performance of solar receivers in solar-thermal systems

et al. 2014

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“…To suppress re-emission losses, a receiver with a stepwise emittance, as shown in the inset to Figure 4a, needs to be engineered [15,[135][136][137][138]. Ideally, such a receiver would feature a complete absorptance across most of the solar spectrum, and zero emittance at lower frequencies overlapping with the thermal emission spectra.…”

Section: Selective Surfaces For Solar Thermal Energy Generationmentioning

confidence: 99%

Heat meets light on the nanoscale

et al. 2016

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Abstract:We discuss the state-of-the-art and remaining challenges in the fundamental understanding and technology development for controlling light-matter interactions in nanophotonic environments in and away from thermal equilibrium. The topics covered range from the basics of the thermodynamics of light emission and absorption to applications in solar thermal energy generation, thermophotovoltaics, optical refrigeration, personalized cooling technologies, development of coherent incandescent light sources, and spinoptics.Keywords: thermal emission; absorption; spectral selectivity; angular selectivity; optical refrigeration; solar thermal energy conversion; thermophotovoltaics; nearfield heat transfer; photon density of states; thermal upconversion; radiative cooling Thermodynamics of light and heatControl and optimization of energy conversion processes involving photon absorption and radiation require detailed understanding of thermodynamic properties of radiation as well as its interaction with matter [1-5]. Historically, thermodynamic treatment of electromagnetic radiation began over a century ago with Planck applying the thermodynamic principles established for a gas of material particles to an analogous "photon gas" [1]. In particular, he showed that thermodynamic parameters, such as the energy, volume, temperature, and pressure can be applied to electromagnetic radiation, reflecting the dual wave-particle nature of photons. In this section, we will review the general thermodynamic principles governing photon propagation and interaction with matter, as well

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“…Thus, the only effect of angular restriction considered here is the suppression of the emission of radiative recombination under oblique angles. It will be shown in the following text that the efficiency limit under angular restriction corresponds to the efficiency limit under optical concentration [4, [38][39][40][41].…”

Section: Radiative Efficiency Limitmentioning

confidence: 99%