Homogeneous Flux Distribution in High-Flux Solar Furnaces

Abstract

Comparisons between experimental data and ray-tracing simulation results are presented for the high-flux SF60 solar furnace available at the Plataforma Solar de Almeria, Spain, which has an estimated thermal power of 60 kW. Since an important issue in many applications of solar concentrated radiation is to obtain a radiation distribution that is as homogeneous as possible over the central working area, so-called radiation homogenisers were also used but the degree of success achieved is just satisfactory, as the results show. Finally, further modelling studies using ray-tracing simulations aiming to attain a homogenous distribution of flux by means of double reflexion using two paraboloid surfaces are presented.

Computer Modelling of the Optical Behavior of Homogenizers in High-Flux Solar Furnaces

“…In high-flux solar concentration systems, the flux of solar radiation that reaches the target is non-homogeneous, as discussed in our previous modelling work [1,2] and illustrated by considerable experimental evidence. Therefore, to expand the application field of solar-driven high-temperature technologies it is essential to improve the temperature homogeneity conditions, because for many applications, it is important to obtain a radiation distribution as homogeneous as possible over the working area [3].…”

“…Throughout this work we assume that the input radiation is formed by random parallel rays coming from a heliostat, that are subsequently concentrated by a paraboloid concentrator [1,2]. To imitate the radiation coming from the heliostat, we generate random points inside a circle with the same area of the projected paraboloid concentrator (see Figure 2).…”

“…gies 2021, 14, x FOR PEER REVIEW 3 of 13 concentrator [1,2]. To imitate the radiation coming from the heliostat, we generate random points inside a circle with the same area of the projected paraboloid concentrator (see Figure 2).…”

“…In solar furnaces, the test table is movable in three directions (East-West, North-South, up and down) thus allowing to place the test samples at a chosen location (near the high-concentration zone, but not necessarily at the focus). When necessary, a 45°-tilted flat mirror (not shown in Figure 1) may be placed at a certain distance between the concentrator and the focal point in order to reflect vertically the solar radiation so that the concentrated solar beam becomes vertically oriented [1,2]. Figure 1.…”

“…For this work, we improved our own ray tracing software (named LAM, Light Analysis Modelling) [1,2] to model the radiation output for several different homogenizers, with different geometries and operating conditions. The software works thus as a laboratory to study homogenizers, allowing us to learn as much as possible about these devices.…”