ABSTRACT Nonimaging optics is a field devoted to the design of optical components for applications such as solar concentration or illumination. In this field, many different techniques have been used to produce optical devices, including the use of reflective and refractive components or inverse engineering techniques. However, many of these optical components are based on translational symmetries, rotational symmetries, or free-form surfaces. We study a new family of nonimaging concentrators called elliptical concentrators. This new family of concentrators provides new capabilities and can have different configurations, either homofocal or nonhomofocal. Translational and rotational concentrators can be considered as particular cases of elliptical concentrators.
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ABSTRACT: The desalination of water is a process wherein the brackish water is purified by removing the salts. With increasing demand for fresh water, there is a vast scope for development of sea water desalination process. A number of methods exist for the desalination process, but solar desalination method promises to save energy in today's energy crunch scenario. A novel solar desalination setup is proposed here. It uses an elliptic hyperboloid concentrator and a helical receiver along with a multi-tray desalination unit to purify water in the most effective manner. The helical receiver proposed in the present work aims at the Dean Flow effect in order to enhance heat transfer in laminar flow. The effectiveness of this property with respect to various physical parameters has been observed and an optimum design has been suggested based on this. The elliptic hyperboloid concentrator is a special design for concentrating solar radiation because of it offers to operate at high efficiency without the requirement of tracking. A detailed ray-tracing code was developed to simulate the radi-ation incident on the concentrator and an accurate estimation of the optical efficiency was made based on this. The two systems were integrated in order to arrive at a maximum output level for the solar desalination system as a whole.Solar Energy 07/2014; 108:515-524. DOI:10.1016/j.solener.2014.07.019 · 3.54 Impact Factor
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ABSTRACT: A new generation of inhomogeneous nonimaging optical concentrators is proposed, able to achieve simultaneously high optical efficiency and acceptance solid angle at a given geometrical concentration factor. General design methods are given, and concentrators are numerically investigated and optimized.Applied Optics 04/2014; 53(10):2256-2266. DOI:10.1364/AO.53.002256 · 1.69 Impact Factor
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ABSTRACT: Ray tracing is an important tool for the design of elliptical–hyperboloid concentrators (EHC). Optical efficiency for a range of parameters such as of incidence angle, concentrator height and different diameters of the receiver can be investigated through ray trace analysis. An extensive theoretical prediction of 2-D and 3-D ray tracing techniques has been adopted in the current investigation to calculate the optical efficiency of the novel EHC. An optical efficiency of 63% was found for a 2-D model of the EHC with the following dimensions: height 0.85 m, aperture length 1m, receiver diameter 0.182 m and concentration ratio of 8X. The reflectivity of the EHC is considered to be 0.94. Due to the three-dimensional nature of the EHC, the optical efficiency was improved to 78% based on 3-D ray trace geometry.