Effects of receiver parameters on the optical efficiency of a fixed linear-focus Fresnel lens solar system with sliding adjustment

To effectively eliminate optical end loss for small-scale linear solar concentrators, a fixed linear-focus Fresnel lens solar system (FLFS) with triangle cavity receiver is described and the principle is provided. The effects of the receiver parameters including receiver position f, solar declination angle δ, solar hour angle ω, internal surface absorptivity α_ab and end plane reflectivity ρ_r on the end loss ratio (μ_oel) and relative optical efficiency (η_re−opt) of the proposed system have been studied by the control variable method and Monte Carlo ray tracing (MCRT) method which is implemented by software TracePro®. Significance tests of critical factors are conducted to assess the effect of receiver parameters. These results revealed that the FLFS could effectively solve the problem of optical end loss of linear solar concentrators. When f=650 mm and δ= 0°, 8°, 16°, and 23°27^′, the corresponding average η_re−opt at ω from 0° to 60° are 0.9459, 0.9422, 0.9145, and 0.8144, respectively. As δ increases, reducing f can ensure the system operates at a high-efficiency state. The η_re−opt shows a positive relationship with α_ab and no relationship with ρ_r. δ occupies the greatest significant influence on η_re−opt, which is followed by ω, α_ab and f.