Optical Methods for Indoor Characterization of Small-Size Solar Concentrators Prototypes

Abstract

The light collection properties of different types of solar concentrators have been investigated by applying conventional and innovative methods of characterization [1, 2]. Four types of optical methods were applied: i) a “direct” method using a laser beam as light source; ii) a “direct” method using a parallel beam simulating the direct component of solar light; iii) a “direct” integral method using a lambertian light source simulating the diffuse component of solar light; iv) an “inverse” method using a lambertian light source applied at the receiver side, thereby reversing the light path. The optical properties derived by applying the above three methods were: i) the local optical collection efficiency, resolved on the entrance point and direction of incidence ii) the overall optical collection efficiency under collimated light, resolved on direction of incidence; iii) the spatial and angular distribution of flux on the receiver.

Optical simulation of Rondine®PV solar concentrators by two inverse characterization methods

“…The original inverse method developed by Parretta et al [17][18][19][20][21][22][23][24][25] for the characterization of solar concentrators is the simplest among the many methods based on measurements with a charge coupled device (CCD) camera. Here we summarize the main features of this method.…”

“…For receivers with non-planar geometry, the Lambertian source should be shaped to reproduce the profile of the receiver surface. When the inverse method is simulated, the planar screen is configured as an ideal absorber and the measured incident irradiance E(θ, ϕ) (see figure 1(b)) is converted into the radiance distribution function of the concentrator, L inv (θ, ϕ), by multiplying by the factor (cos θ ) −4 [17][18][19][20][21][22][23][24][25].…”

“…The optical efficiency and flux distribution on the receiver will be evaluated therefore as a function of the orientation of the beam with respect to a reference frame fixed to the concentrator, and as a function of wavelength, if the experimental apparatus is provided for spectral measurements. The 'optical characterization' of a solar concentrator can be performed following different approaches [6][7][8][9][10]; here we will focus our attention on the so-called 'inverse' method of characterization [17][18][19][20][21][22][23][24][25]. It is the opposite of the commonly used 'direct' method, where the angle-resolved transmission efficiency is obtained by irradiating the input aperture with a parallel beam of known irradiance and measuring the output flux for all the significant incidence directions, polar and azimuthal.…”

Development of a mirror‐based LCPV module and test results

“…The optical angular acceptance of this geometry, with receiver positioned at the exit aperture of the optics, is of Development of a mirror-based LCPV module and test results A. Antonini, M. A. Butturi and P. Zurru approximately ±5°, with a relative optical efficiency curve as shown in Figure 3, for two relevant directions of misalignment [20].…”