Enhancing the efficiency of solar concentrators by controlled optical aberrations: Method and photovoltaic application

Giannuzzi, Alessandra; Diolaiti, Emiliano; Lombini, Matteo; Rosa, Adriano Giuseppe De; Marano, B.; Bregoli, Giovanni; Cosentino, Giuseppe; Foppiani, Italo; Schreiber, Laura

doi:10.1016/j.apenergy.2015.01.085

Cited by 22 publications

(11 citation statements)

References 39 publications

(38 reference statements)

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“…At present, it is mainly to improve the flux uniformity of the receiver by designing a new solar dish concentrator with nonparabolic mirror, but it is limited to a simple plane or tubular absorber . There are 3 main types of new dish concentrators, namely, a solar concentrator consisting of multiple planar mirror units, solar concentrator consisting of multiple points focusing mirror unit, and solar concentrator with new reflector mirror surface . For example, Chong et al proposed a nonimaging planar concentrator and its design method to obtain a uniform flux distribution on the plane receiver.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Chong et al proposed a nonimaging planar concentrator and its design method to obtain a uniform flux distribution on the plane receiver. Giannuzzi et al proposed a general method, based on controlled static aberrations induced in the multifaceted point focus concentrator to improve the flux uniformity on a solar cell. Zhou et al proposed 2 versions of nonimaging dish concentrator designed for providing uniform flux profiles on the plane receiver.…”

Section: Introductionmentioning

confidence: 99%

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Mirror rearrangement optimization for uniform flux distribution on the cavity receiver of solar parabolic dish concentrator system

2018

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Summary The nonuniform and high‐gradient solar radiation flux on the absorber surface of solar dish concentrator/cavity receiver (SDCR) system will affect its operational reliability and service lifetime. Therefore, homogenization of the flux distribution is critical and important. In this paper, 2 mirror rearrangement strategies and its optimization method by combining a novel ray tracing method and the genetic algorithm are proposed to optimize the parabolic dish concentrator (PDC) so as to realize the uniform flux distribution on the absorber surface inside the cavity receiver of SDCR system. The mirror rearrangement strategy includes a mirror rotation strategy and mirror translation strategy, which rotate and translate (along the focal axis) each mirror unit of the PDC to achieve multipoint aiming, respectively. Firstly, a correlation model between the focus spot radius and mirror rearrangement parameters is derived as constraint model to optimize the PDC. Secondly, a novel method named motion accumulation ray‐tracing method is proposed to reduce the optical simulation time. The optical model by motion accumulation ray‐tracing method and optimization model of SDCR system are established in detailed, and then, an optimization program by combining a ray‐tracing code and genetic algorithm code in C++ is developed and verified. Finally, 3 typical cavity receivers, namely, cylindrical, conical, and spherical, are taken as examples to fully verify the effectiveness of these proposed methods. The results show that the optimized PDC by mirror rearrangement strategies can not only greatly improve the flux uniformity (ie, reduce the nonuniformity factor) and reduce the peak local concentration ratio of the absorber surface but also obtain excellent optical efficiency and direct useful energy ratio. A better optimization results when the PDC is optimized by mirror rotation strategy at aperture radius of 7.0 m, focal length of 6.00 m, and ring number of 6; the nonuniform factor of the cylindrical, conical, and spherical cavity receivers is greatly reduced from 0.63, 0.67, and 0.45 to 0.18, 0.17, and 0.26, respectively; the peak local concentration ratio is reduced from 1140.00, 1399.00, and 633.30 to 709.10, 794.00, and 505.90, respectively; and the optical efficiency of SDCR system is as high as 92.01%, 92.13%, and 92.71%, respectively. These results also show that the dish concentrator with same focal length can match different cavity receivers by mirror rearrangement and it can obtain excellent flux uniformity.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mirror rearrangement optimization for uniform flux distribution on the cavity receiver of solar parabolic dish concentrator system

2018

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“…The SOLARIS concentrator [29] has been conceived as a single stage multi-dish reflective optics made by mirrors: seven mirrors substitute the traditional segmented dish, focusing the light at the same point so that the final illumination pattern impinging on the receiver results from the sum of the single incoherent illumination produced. Each mirror is a free-form optics, a type of optics often used for solving the prescribed irradiance problem in lenses of limited dimensions often used as SOs.…”

Section: The Solaris Concentrator Modelingmentioning

confidence: 99%

“…A CPV dense array concentrator model based on a new optical concept has been briefly described in this work [29]. The used design method has been conceived to reduce the current mismatch problem by acting on the optical part.…”

Section: Introductionmentioning

confidence: 99%

A novel solar concentrator system for combined heat and power application in residential sector

Ancona¹,

Bianchi²,

Diolaiti

et al. 2017

Applied Energy

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“…As energy consumption increases, pollution and its reduction are urgent challenges faced by human society. As a resource for sustainable development, green energy has attracted increasing attention from researchers and industries [1][2][3]. Therefore, in recent years, the trend of developing renewable and clean energy has been increasing, with hydropower playing an important role and developing at an unprecedented rate [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Tip Clearance Size on Tubular Turbine Leakage Characteristics

Zhu

2021

Processes

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To study the effect of tip clearance on unsteady flow in a tubular turbine, a full-channel numerical calculation was carried out based on the SST k–ω turbulence model using a power-plant prototype as the research object. Tip leakage flow characteristics of three clearance δ schemes were compared. The results show that the clearance value is directly proportional to the axial velocity, momentum, and flow sum of the leakage flow but inversely proportional to turbulent kinetic energy. At approximately 35–50% of the flow direction, velocity and turbulent kinetic energy of the leakage flow show the trough and peak variation law, respectively. The leakage vortex includes a primary tip leakage vortex (PTLV) and a secondary tip leakage vortex (STLV). Increasing clearance increases the vortex strength of both parts, as the STLV vortex core overlaps Core A of PTLV, and Core B of PTLV becomes the main part of the tip leakage vortex. A “right angle effect” causes flow separation on the pressure side of the tip, and a local low-pressure area subsequently generates a separation vortex. Increasing the gap strengthens the separation vortex, intensifying the flow instability. Tip clearance should therefore be maximally reduced in tubular turbines, barring other considerations.

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Enhancing the efficiency of solar concentrators by controlled optical aberrations: Method and photovoltaic application

Cited by 22 publications

References 39 publications

Mirror rearrangement optimization for uniform flux distribution on the cavity receiver of solar parabolic dish concentrator system

Mirror rearrangement optimization for uniform flux distribution on the cavity receiver of solar parabolic dish concentrator system

A novel solar concentrator system for combined heat and power application in residential sector

Effect of Tip Clearance Size on Tubular Turbine Leakage Characteristics

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