Study on the influence of dust accumulation on the photothermal performance of a trough solar system based on space-time factors in alpine areas

Abstract

Based on the dust accumulation and distribution characteristics of concentrator surfaces in alpine regions, a comparative experimental platform for measuring the energy flux density of the focal plane and thermal performance was developed in this study. By combining theory and experimentation, the influence of time (dust deposition density) and space (concentrator tilt angle) on the dust distribution characteristics and photothermal performance of a trough solar system was studied. The optical loss caused by concentrator dust was evaluated based on the intercept factor, while the thermodynamic loss caused by dust was evaluated based on the collecting efficiency and exergy efficiency. The results demonstrate that concentrator dust at a tilt angle of 60° will lead to a maximum center shift of 1.66 mm of the focal plane. Importantly, the inconsistency between thermal performance and dust deposition density indicates that the dust distribution characteristics caused by tilt angle have a significant influence on the thermal performance of the system. Comparatively, an increase in dust deposition density from 0 to 2.46 g/m2 leads to a 20.58% relative reflectivity loss, together with 48.30% and 55.08% reductions in the collecting efficiency and exergy efficiency, respectively. This study revealed the influence of space–time factors on dust distribution characteristics and photothermal performance, which can provide design ideas regarding dust removal for the application of trough solar systems in alpine areas.