Optical assessment of nonimaging concentrators

Abstract

An optical measurement method for nonimaging radiation concentrators is proposed. A Lambertian light source is placed in the exit aperture of the concentrator. Looking into the concentrator's entrance aperture from a remote position, one can photograph the transmission patterns. The patterns show the transmission of radiation through the concentrator with the full resolution of the four-dimensional phase space of geometric optics. By matching ray-tracing simulations to the measurement, one can achieve detailed and accurate information about the geometry of the concentrator. This is a remote, noncontact measurement and can be performed in situ for installed concentrators. Additional information regarding small-scale reflector waviness and surface reflectivity can also be obtained from the same measurement with additional analysis.

Solar ray transfer inside sea-shell stationary trough solar concentrator

“…2 is called the aperture angle. [1][2][3] This is the angle between the TF and the tangent on the reflector parabola at the rim point T. This angle is the same as the angle between the tangent on the reflector parabola at the rim point T and the symmetry line FO of the reflector parabola. For the investigated concentrator, d ¼ 48 .…”

“…Their theory was given by Strebkov and Tverynovic, 1 and an optical assessment presented by Timinger et al 2 R€ onnelid et al 3 studied the impact of high latitudes on the optical design of solar systems. These concentrators are used to transfer solar energy to heat and/or to electricity.…”

“…For instance, by using experiments, the optical assessment of the concentrators was performed by Strebkov and Tverynovic, 1 Bader et al, 5 and Timinger et al 2 The assessment of ray tracing by numerical procedures requires specialized proprietary expensive software that is not readily available in industry and academia. For instance, the optical assessment of the concentrators a) Author to whom correspondence should be addressed.…”

Development of procedures and equipment for indoor characterization of concentrator photovoltaic systems

“…For concentrators of large field of view (i.e., medium-low geometrical concentration), the evaluation of the transmitted flux can be performed by recording several photographs of the transmission pattern of radiation emanating through the entrance aperture while a Lambertian source is placed at the exit of the concentrator, and a CCD camera is displaced along a single axis (Timinger et al, 2000).…”