Thermal performance of solar concentrator/cavity receiver systems

Harris, J. Arthur; Lenz, Terry G.

doi:10.1016/0038-092x(85)90170-7

Cited by 166 publications

(95 citation statements)

References 4 publications

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“…Since the radiation emitted at angles larger than the acceptance angle is confined, the absorber in the cavity effectively has directional selectivity. It is worth noting that many solar receiver cavities are "hot cavities," in that the entire cavity is at elevated temperature (Harris and Lenz, 1985), whereas in this cavity only the absorber is hot, a configuration which is compatible with solid state solar-conversion technologies such as solar thermoelectric generators and solar thermo-photovoltaics (Baranowski et al, 2012;Kraemer et al, 2011;Lenert et al, 2014). The performance of the cavity is measured by the effective emittance of the absorber in the cavity.…”

Section: Cavity Receiver Conceptmentioning

confidence: 99%

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%

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

et al. 2014

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“…The main features over convectional designs are the curved bottom and the narrow aperture. A simplified analysis of this type of receiver was presented in [7].…”

Section: System Structure and Design Approachmentioning

confidence: 99%

“…Cavity receivers increase the system efficiency by decreasing radiation, thermal radiation and convection heat losses. However some trade-offs between these loss mechanisms exist when optimizing the overall efficiency [7].…”

Section: Introductionmentioning

confidence: 99%

Radiation Performance of a Cavity Receiver for a Parabolic Dish Solar Concentrator System

López¹,

Arenas²,

Baños³

2024

RE&PQJ

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Abstract. The radiation performance of a modified cavity receiver for a low-cost concentrating solar power plant is studied. The optical phenomenon taking place is modelled by using a ray tracing technique based on a finite element approach. This design is also compared to a flat receiver. Corrections for sunlight and optical errors of the parabolic dish are included. Its efficiency is analysed by varying some geometrical parameters of the receiver, maximizing the total power absorbed. It is found that the flux density on the cavity walls is less than on the flat receiver walls, hence decreasing heat losses. Also, in order to reach a maximum radiation performance the receiver is to be placed closer to the concentrator from the focal position. However, the aperture does not improve notably its efficiency, although it has an important role in the convection heat losses as shown in previous works. Finally by varying the cavity diameter it is possible to improve the efficiency when it is well adjusted to the radiation performance of the concentrator on the focal point.

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“…Cavity shaped solar receivers are designed to minimize re-radiation losses and have a better coupling with the concentrated solar flux provided by the dish [14][15][16]. The Working Fluid (WF) inside the receiver cavity can be heated either directly or indirectly.…”

Section: Introductionmentioning

confidence: 99%

Charge and Discharge Analyses of a PCM Storage System Integrated in a High-Temperature Solar Receiver

Giovannelli

Bashir

2017

Energies

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Solar Dish Micro Gas Turbine (MGT) systems have the potential to become interesting small-scale power plants in off-grid or mini-grid contexts for electricity or poly-generation production. The main challenging component of such systems is the solar receiver which should operate at high temperatures with concentrated solar radiations, which strongly vary with time. This paper deals with the design and the analysis of a novel solar receiver integrated with a short-term storage system based on Phase Change Materials to prevent sudden variations in the maximum temperature of the MGT working fluid. Particularly, the charge and discharge behavior of the storage system was analyzed by means of Computational Fluid Dynamic methods to evaluate the potentiality of the concept and the component capabilities. Achieved results were highly satisfactory: the novel solar receiver has a good thermal inertia and can prevent relevant fluctuations in the working fluid temperature for 20-30 min.

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Thermal performance of solar concentrator/cavity receiver systems

Cited by 166 publications

References 4 publications

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

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

Radiation Performance of a Cavity Receiver for a Parabolic Dish Solar Concentrator System

Charge and Discharge Analyses of a PCM Storage System Integrated in a High-Temperature Solar Receiver

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