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Dust accumulation on the concentrator of a high concentration photovoltaic/thermal (HCPVT) system can cause significant performance loss. In our work, the effect of seasonal dust deposition on the output performance of an HCPVT system with a point-focused Fresnel lens was studied in natural dust-deposition experiments. The changes of thermoelectric performance and exergy performance of the system under different dust accumulation levels were analyzed, and the influence of dust accumulation density on the total efficiency was determined. The results show that when the average dust density increases by 1 g/m2, the transmittance of the Fresnel lens decreases by 2.73%, thermal efficiency by 7.58%, and electrical efficiency by 1.74%. The temperature rise of the all-day operation system decreased by 2.31%, and the exergy efficiency loss reached 17.32%. Model fitting and calculation show that when the dust concentration is 8.81 g/m2, the all-day total/thermoelectric power output is 5.27 kW less than that with a clean lens. [Display omitted] • The effects of dust deposition on an HCPVT system in a semi-arid climate are studied. • Both the thermal and the electrical efficiency are analyzed with dust density increase. • The exergy efficiency decreases 17.32% per 1 g/m2 increase in dust density. • We studied dust densities from zero to 8.813 g/m2. [ABSTRACT FROM AUTHOR]

Solar reflectors are exposed to outdoor environments where dust accumulation is a primary degrading factor on optical performance. In this study, the effect of dust accumulation on reflectivity at different positions on the reflector of a parabolic trough solar thermal power plant in Hohhot, China was investigated and analyzed. The physical and chemical properties of dust accumulation were tested using a combination of spectrophotometer, scanning electron microscopy, and X-ray diffraction. The results showed that dust accumulation on the bottom edge of the reflector caused the largest decrease in reflectivity compared to dust on the center and top edge. In addition, dust particles at Hohhot were dominated by quartz (SiO 2 , 53.5%), followed by calcium oxide (CaCO 3 , 25.4%), and some minor feldspar minerals (NaAlSi 3 O 8 , 21.1%). However, some characteristics of the dust could not be determined by experimental measurements. To address this gap, a physical model was proposed to predict the impact of dust accumulation on light reflectivity of the reflector. Different physical parameters of the model are discussed, such as the size of the particles, diaphaneity, the incidence light angle, and tilt angle. The maximum relative deviation between the mathematical model and the experimental results was only 1%. • The effect of dust accumulation on reflectivity is investigated in cold regions. • The optical performance of dusty reflector is studied with increasing wavelength. • Average reflectivity reduces by 10% with increase of 1 g/m2 dust accumulation. • A model is developed to predict the cleanliness factor of dusty reflector. • The model results are compared to the experiment results. [ABSTRACT FROM AUTHOR]