Experimental measurements of a prototype high-concentration Fresnel lens and sun-tracking method for photovoltaic panel’s efficiency enhancement

This paper investigates the potential of a new integrated solar concentrated photovoltaic (CPV) system that uses a solo point focus Fresnel lens for multiple multi-junction solar cells (MJSCs). The proposed system comprises of an FL concentrator as the primary optical element, a multi-leg homogeniser as the secondary optical element (SOE), a plano-concave lens, and four MJSCs. A three-dimensional model of this system was developed using the ray tracing method to predict the influence of aperture width, height, and position with respect to MJSCs of different reflective and refractive SOE on the overall optical efficiency of the system and the irradiance uniformity achieved on the MJSCs’ surfaces. The results show that the refractive homogeniser using N-BK7 glass can achieve higher optical efficiency (79%) compared to the reflective homogeniser (57.5%). In addition, the peak to average ratio of illumination at MJSCs for the reflective homogeniser ranges from 1.07 to 1.14, while for the refractive homogeniser, it ranges from 1.06 to 1.34, causing minimum effects on the electrical performance of the MJSCs. The novelty of this paper is the development of a high concentration CPV system that integrates multiple MJSCs with a uniform distribution of rays, unlike the conventional CPV systems that utilise a single concentrator onto a single MJSC. The optical efficiency of the CPV system was also examined using both the types of homogeniser (reflective and refractive).

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Solar Thermophotovoltaic Converters Based on Tungsten Emitters

Journal of Solar Energy Engineering ◽

10.1115/1.2734576 ◽

2006 ◽

Vol 129 (3) ◽

pp. 298-303 ◽

Cited By ~ 27

Author(s):

V. M. Andreev ◽

A. S. Vlasov ◽

V. P. Khvostikov ◽

O. A. Khvostikova ◽

P. Y. Gazaryan ◽

...

Keyword(s):

Band Gap ◽

High Efficiency ◽

Radiation Spectrum ◽

Cost Effective ◽

Fresnel Lens ◽

Photocurrent Density ◽

Back Side ◽

High Concentration ◽

Emitter System ◽

Solar Powered

Results of a solar thermophotovoltaic (STPV) system study are reported. Modeling of the STPV module performance and the analysis of various parameters influencing the system are presented. The ways for the STPV system efficiency to increase and their magnitude are considered such as: improvement of the emitter radiation selectivity and application of selective filters for better matching the emitter radiation spectrum and cell photoresponse; application of the cells with a back side reflector for recycling the sub-band gap photons; and development of low-band gap tandem TPV cells for better utilization of the radiation spectrum. Sunlight concentrator and STPV modules were designed, fabricated, and tested under indoor and outdoor conditions. A cost-effective sunlight concentrator with Fresnel lens was developed as a primary concentrator and a secondary quartz meniscus lens ensured the high concentration ratio of ∼4000×, which is necessary for achieving the high efficiency of the concentrator–emitter system owing to trap escaping radiation. Several types of STPV modules have been developed and tested under concentrated sunlight. Photocurrent density of 4.5A∕cm2 was registered in a photoreceiver based on 1×1cm2GaSb cells under a solar powered tungsten emitter.

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A Novel High Concentration Fresnel Lens as a Solar Concentrator

Journal of Solar Energy Engineering ◽

10.1115/1.4051975 ◽

2021 ◽

pp. 1-29

Author(s):

Kuldeep Awasthi ◽

Desireddy Shashidhar Reddy ◽

Mohd. Kaleem Khan

Keyword(s):

Optical Axis ◽

Spherical Aberration ◽

Spherical Surface ◽

Fresnel Lens ◽

High Concentration ◽

Aperture Diameter ◽

Convex Lens ◽

Flat Base ◽

Fresnel Lenses ◽

Outer Vertex

Abstract This paper describes the design methodology for a novel Fresnel lens. The original Fresnel lens is obtained from a plano-convex lens, whose spherical surface is split into a number of divisions (called facets), collapsed onto the flat base. Thus, all the facets of the original Fresnel lens have the same radius as that of the plano-convex lens. The proposed design aims to achieve better ray concentration and reduced spherical aberration than the original Fresnel lens by constructing spherical facets with unequal radii. The centers and radii of facets are constrained so that the ray refracted from the bottom vertex of each facet on one side of the optical axis and the ray refracted from the outer vertex of the corresponding facet on the other side of the optical axis must intersect at the focal plane. The proposed lens design has resulted in a 275% gain in the concentration ratio and a 72.5% reduction in the spherical aberration compared to the original lens of the same aperture diameter and number of facets. The performance of both novel and original Fresnel lenses when used as solar concentrators with a conical coil receiver is evaluated. The novel Fresnel lens led to increased heat gain and resulted in a compact solar collector design.

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