Person: Álvarez Fernández-Balbuena, Antonio
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First Name
Antonio
Last Name
Álvarez Fernández-Balbuena
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Department
Óptica
Area
Optica
Identifiers
10 results
Search Results
Now showing 1 - 10 of 10
Item Horizontal daylighting system for office buildings(Energy and Buildings, 2013) Vázquez Molini, Daniel; González Montes, Mario; Álvarez Fernández-Balbuena, AntonioThis work is focused on a sunlight collection device for solar lighting systems aimed at non-residential buildings. The design takes advantage of solar energy that reaches the facade of the building for lighting purposes, thereby reducing building energy consumption by supplementing it with clean, renewable energy. This daylighting system's structure comprises a light collector located outside the vertical facade of the building, a modular light guide that runs along the horizontal false ceiling and light extractor luminaires strategically positioned along the guide. The system is configured specifically to the particular characteristics of each building (façade orientation, latitude and longitude) to optimize the global performance. The present paper describes in detail the anidolic collecting system as a part of the comprehensive daylighting system. However the entire daylighting system has been completely developed and experimentally tested, and its prototype is currently integrated into Lledó S.A company's facilities.Item Smooth light extraction in lighting optical fibre(Illumination Optics II, 2011) Álvarez Fernández-Balbuena, Antonio; Vázquez Molini, Daniel; García Botella, Ángel; Martínez Antón, Juan Carlos; Bernabeu Martínez, Eusebio; Kidger, Tina E.; David, StuartRecent advances in LED technology have relegated the use of optical fibre for general lighting, but there are several applications where it can be used as scanners lighting systems, daylight, cultural heritage lighting, sensors, explosion risky spaces, etc. Nowadays the use of high intensity LED to inject light in optical fibre increases the possibility of conjugate fibre + LED for lighting applications. New optical fibres of plastic materials, high core diameter up to 12.6 mm transmit light with little attenuation in the visible spectrum but there is no an efficient and controlled way to extract the light during the fibre path. Side extracting fibres extracts all the light on 2π angle so is not well suited for controlled lighting. In this paper we present an extraction system for mono-filament optical fibre which provides efficient and controlled light distribution. These lighting parameters can be controlled with an algorithm that set the position, depth and shape of the optical extraction system. The extraction system works by total internal reflection in the core of the fibre with high efficiency and low cost. A 10 m length prototype is made with 45° sectional cuts in the fibre core as extraction system. The system is tested with a 1W white LED illuminator in one side.Item Optics detailed analysis of an improved collimation system for LED light sources(Illumination Optics II, 2011) González Montes, Mario; Vázquez Molini, Daniel; Álvarez Fernández-Balbuena, Antonio; García Botella, Ángel; Bernabeu Martínez, Eusebio; Kidger, Tina E.; David, StuartThroughout present study will be discusses the influence of the manufacturing margins, adjustment precision and ray model accuracy of a collimating LED unit in the overall system performance. It will be also analyzed the angular performance and the collimated in relation to the relative position of the LED and the collimator's dimensions. Finally the results will be compared with existing publications in this field.Item Hyperparabolic concentrators(Applied Optics, 2009) García Botella, Ángel; Álvarez Fernández-Balbuena, Antonio; Vázquez Molini, Daniel; Bernabeu Martínez, Eusebio; González Cano, AgustínWe present a family of three-dimensional concentrators constructed from the photic field generated by a Lambertian emitter. The profile of these concentrators is obtained from the field lines for a two-dimensional truncated wedge and is based on the union between a hyperbola and a tilted parabola. By revolution of this profile, we obtain hyperparabolic concentrators (HPCs). In the limiting case when the focal length of the hyperbola becomes the radius of the exit aperture, the HPC becomes the well-known compound parabolic concentrator. On the other hand, when the focal length of the hyperbola becomes infinite, the HPC achieves the thermodynamic limit of concentration.Item Improved and customized secondary optics for photo-voltaic concentrators(Proceedings of SPIE, Nonimaging Optics: Efficient Design for Illumination and Solar Concentration XII, 2015) Vázquez Molini, Daniel; Álvarez Fernández-Balbuena, Antonio; García Botella, Ángel; Alda, JavierIn this contribution the line flow method is applied to an optimized secondary optics in a photovoltaic concentration system where the primary optics is already defined and characterized. This method is a particular application of photic field theory. This method uses the parameterization of a given primary optics, including actual tolerances of the manufacturing process. The design of the secondary optics is constrained by the selection of primary optics and maximizes the concentration at a previously specified collection area. The geometry of the secondary element is calculated by using a virtual source, which sends light in a first concentration step. This allows us to calculate the line flow for this specific case. This concept allows designing more compact and efficient secondary optics of photovoltaic systems.Item High-efficiency light-emitting diode collimator(Optical Engineering, 2010) Vázquez Molini, Daniel; González Montes, Mario; Álvarez Fernández-Balbuena, Antonio; Bernabeu Martínez, EusebioWe describe an analytical and numerical method to design and optimize LED (light-emitting diode) collimators. The optimization process is confirmed by optical simulations and experimental measurements of a scaled prototype. The collimator's definitive geometry and design parameters rely on the LED's emitting characteristics and the employed collimator material. The resulting parabolic-elliptical-based collimator shows an optimum performance and a compact structure with requirement for mirrored surfaces.Item Light output losses of prism light guides(Optical Systems Design 2012, 2012) García Fernández, Berta; Vázquez Molini, Daniel; Álvarez Fernández-Balbuena, Antonio; Bernabeu Martínez, EusebioCylindrical prismatic hollow light guides are able to transmit daylight properly into the spaces of a building in which natural light has a difficult access. Transmission through the guide depends on the optical characteristics of the material, the shape of the guide and the fidelity of the geometry in prisms structure. It is important to analyse the micro-structure prism imperfections of the surfaces such as the existence of a curved area on peaks prism which modify the behaviour of the prism film; these imperfections, change the optical path and therefore the rays are directed to other directions instead of undergoing total internal reflections. In this paper, several cylindrical guides made of transparent dielectric material characterized with an absorption factor have been developed. A numerical analysis has been carried out by software tools to analyse the flux distribution in the light guidance system comparing its efficiency by optical analysis in different simulations. These simulations include high reproductively prism related to the light pipe’s material and optical properties including a study of the impact of imperfect geometry which is necessary to allow rigorous comparisons with the experimental simulations. The simulated results have been compared with experimental data obtained through real scale analysis. The experimental measurements have revealed effectiveness of 66.7 % in the aspect ratio of 30.Item Improved spatial integrator with axicon-dioptric elements(Optical Engineering, 2006) Álvarez Fernández-Balbuena, Antonio; Vázquez Molini, Daniel; Alda, Javier; Bernabeu Martínez, EusebioThe flux transfer efficiency of an optical array with spatial integration has been improved by adding a new element at the input surface. The optical characteristics of the input surfaces of the individual units do not affect the spatial integration property. We propose to fill this input surface with a nested optical array designed to transfer as much energy as possible to the plane of the synthetic image of the spatial integrator array. Several designs for the individual units of this array are discussed. The most promising design consists of a cylindrical axicon-diopter element. This element has been simulated, fabricated, and tested, showing the expected improvement in performance.Item Achromatic Fresnel Lens with Improved Efficiency for PV Systems(International Journal of Photoenergy, 2014) González Montes, Mario; Martínez Antón, Juan Carlos; Vázquez Molini, Daniel; Álvarez Fernández-Balbuena, Antonio; Bernabeu Martínez, EusebioThis work is aimed to design and evaluate different achromatic Fresnel lens solutions capable of operating as concentrators aimed at photovoltaic cells systems. Throughout this study, the theoretical parametric design of the achromatic lens will be shown together with a series of simulations to verify the performance of each lens topology. The results will be compared with a standard Fresnel lens to ascertain the validity and effectiveness of the obtained design. Finally, a novel kind of hybrid lens is proposed, which combines the advantages of each type of lens (standard and Fresnel) according to the optimal operating region of each design. Efficiency and concentration ratios of each particular lens are shown, regarding lens dimension, light’s incidence angle, or wavelength. Through this innovative achromatic design concentration ratios above 1000 suns, which hardly reach standard Fresnel lenses. Furthermore chromatic dispersion is minimized and the efficiency rate is over 85% of efficiency for a wide spectral range (from 350 nm to 1100 nm).Item Beacon system based on light-emitting diode sources for runways lighting(Optical engineering, 2014) González Montes, Mario; Vázquez Molini, Daniel; Álvarez Fernández-Balbuena, Antonio; Bernabeu Martínez, EusebioNew aeronautical ground lighting techniques are becoming increasingly important to ensure the safety and reduce the maintenance costs of the plane's tracks. Until recently, tracks had embedded lighting systems whose sources were based on incandescent lamps. But incandescent lamps have several disadvantages: high energy consumption and frequent breakdowns that result in high maintenance costs (lamp average life-time is similar to 1500 operating hours) and the lamp's technology has a lack of new lighting functions, such as signal handling and modification. To solve these problems, the industry has developed systems based on light-emitting diode (LED) technology with improved features: (1) LED lighting consumes one tenth the power, (2) it improves preventive maintenance (an LED's lifetime range is between 25,000 and 100,000 hours), and (3) LED lighting technology can be controlled remotely according to the needs of the track configuration. LEDs have been in use for more than three decades, but only recently, around 2002, have they begun to be used as visual aids, representing the greatest potential change for airport lighting since their inception in the 1920s. Currently, embedded LED systems are not being broadly used due to the specific constraints of the rules and regulations of airports (beacon dimensions, power system technology, etc.). The fundamental requirements applied to embedded lighting systems are to be hosted on a volume where the dimensions are usually critical and also to integrate all the essential components for operation. An embedded architecture that meets the lighting regulations for airport runways is presented. The present work is divided into three main tasks: development of an optical system to optimize lighting according to International Civil Aviation Organization, manufacturing prototype, and model validation.