Constructing the large-scale collimating solar simulator with a light half-divergence angle <1° using only collimating radiation modules

Large-scale collimating solar simulators (CSSs) with a light half divergence angle (HDA) of less than 1° have been developed. The small HDA ensures that the CSS can effectively simulate the optical behavior between natural sunlight and optical devices. However, the construction of large-scale CSSs still has a strict threshold because additional optical modules (AOMs), such as large-area collimating mirrors, are usually required to correct the light into collimated light. The manufacturing, installation, and adjustment of these precision optical devices pose significant challenges. An excellent scheme to avoid AOMs is to use the collimating radiation module (CRM), which can directly produce collimated light. Unfortunately, CRM can only produce light with an HDA of more than 3° at present, far larger than that of CSS with AOMs. Here, we report a CRM that can directly produce light with excellent collimation (an HDA<0.955°) and uniformity (>90 %). We accomplished this by analyzing the deviations between an idealized geometric optical model and actual CRMs and eliminating them with high-precision parts and a high-resolution adjustment method. We further used 24 CRMs to prove that the single-module collimating solar simulator (SMCSS, a radiation area of 2.55 m × 1.57 m) could be modularly constructed by them. Experimental investigations involving light-concentrating experiments on a parabolic trough collector demonstrated the superior collimation and simulation capabilities of the SMCSS. By eliminating the need for AOMs, the CRM and SMCSS significantly reduce system complexity and cost and lower the construction threshold for large-scale CSSs. It will benefit all experimental scenarios that need large-area collimated light and greatly promote the application of large-scale CSS in civilian solar research.