Caracteristicas Opticas En Aluminio Utilizado Para Fabricar Concentrador Solar

Reflectance fetures of two parabolic solar concentrators
Ana Luz Muñoz Zurita, Joaquín Campos Acostab ,
Carlos G. Martínezc and Alicia Pons Agliod

Abstract
Collection of solar energy with the help of a cylindrical parabola collector has been the subject of many investigations. In order to optimize the collector parameters for maximum energy collection at a given temperature, it isnecessary to investigate the effect of several parameters on the amount of absorbed energy and the thermal losses from the absorber.

The reflecting metallic film is used in solar concentrators. The overall efficiency for the solar energy conversion process depends on the reflective properties of the film. We are presenting an essentially specular high reflectance concentrator in the solar wavelengthrange (300-2500nm), because the diffused component is wasted. In this communication, we also analyse the reflectance of two different types of aluminium parabolic solar concentrators fabricated in the Mechanics and Electrics Faculty of the University of Coahuila (FIME-UAC).
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Contact information
a anniezurita@gmail.com
Universidad Autónoma deCoahuila, FIME-Torreón.
Carr. Torreón-Matamoros km 7.5 Ciudad Universitaria. Torreón, Coahuila México
b joaquin.campos@csic.es
Instituto de Optica “Daza de Valdés”, CSIC
Serrano 144, Madrid, España.
c carlosgmtzc@hotmail.com
Universidad Autónoma de Coahuila, FIME-Torreón.
Carr. Torreón-Matamoros km 7.5 Ciudad Universitaria. Torreón, Coahuila México
d alicia.pons@csic.es
Instituto deOptica “Daza de Valdés”, CSIC
Serrano 144, Madrid, España

Introduction
Aluminium is used for design and construction of lightweight transportation systems such as satellites, aircraft, high-speed trains and fast ferries and solar collectors [1-3]. In the case of solar collectors is possible to use different types, such as using two different films:

The first is Aluminum T6 temper 6061 whichhas an ultimate tensile strength of at least 42,000 psi (300 MPa) and yield strength of at least 35,000 psi (241 MPa). More typical values are 45,000 psi (310 MPa) and 40,000 psi (275 MPa), respectively [4]. Films with thicknesses of 0.250 inch (6.35 mm) or less, have elongation of 8% or more; in thicker sections, they have elongation of 10%. The 6061 is a precipitation hardening aluminum alloy,containing magnesium and silicon as its major alloying elements [5]. The second is Aluminum 5182 H19 which includes Al-Mg and Al-Mg-Mn types. They are mainly stronger than 3000 series and have good corrosion resistance and weldability combined with formability [6]. The composition of the aluminum substrate can be specifically designed for formability as well as for high strength. Optimization of thematerial according to its alloy, temper, thickness, geometry and reverse-side design can be tailored to suit the different types of mirror construction.

These special substrate qualities allow individually optimized and cost-efficient mirror construction. The mirror-finish coating consists of a polymer foil with a silver reflective coating which possesses outstanding reflectance propertiesand good resistance to weathering. Until a few years ago highly reflective aluminized sheet materials were predominantly used as reflectors for lamps in office and industrial buildings. Because of their good mechanical properties and low cost compared to silvered glass mirrors, aluminized reflectors are being an excellent alternative to high temperature solar concentrating technologies. Furthermorehigh reflectance aluminized sheet is already being successfully applied in low concentrating technologies like compound parabolic concentrator (CPC) troughs and day lightening. The optical analysis of solar collectors with parabolic reflectors must take into account many different effects, such as the finite size of sun, aberrations at nonnormal incidence, as well as errors in surface contour...