Techno-economic analysis of the impact of soiling on PVT system under desert climate using a multi-scale analysis: Experimental and CFD modeling

Photovoltaic- thermal (PVT) collectors are increasingly proposed for hot arid regions. However, photovoltaic systems installed under such climates are strongly affected by environmental conditions, among which soiling is one of the most severe in desert environments. When suspended particles present in the atmosphere are deposited on the module surface, less solar radiation reaches the photovoltaic cells and the performance decreases accordingly. Almost all published soiling studies address conventional PV modules. The few investigations devoted to PVT collectors rely either on short-term exposure tests or on numerically imposed dust densities, and none propagates a measured, site-specific soiling profile through a validated thermal model up to a cost indicator. The present study addresses this gap through a multi-scale assessment framework that combines in-situ soiling measurements, CFD modeling, and techno-economic simulation, in order to quantify the impact of dust deposition on PVT performance under the hot desert climate of Muscat, Oman. For this purpose, dedicated soiling station logged an average daily soiling rate of ~0.5%, with uncleaned modules losses achieve 25% of their output. In the other hand, a confirmed strong predictive CFD model of the PVT collector was validated against both measured data and literature results with deviations below 2.24%. The results reveal that, under clean conditions, the PVT module consistently outperformed standalone PV, reaching a peak daily output of 308 Wh versus 248 Wh and a mean efficiency of 15.6% versus 12.4%, owing to its active cooling loop suppressing temperature-driven electrical losses. However, when the longer cleaning intervals are performed, performance deviation decreased the PVT-PV energy gap (25.93% clean to 21.66% monthly), while increase the relative LCOE increase of PVT compared to PV (6.78% to 8.59%). These results identify bi-weekly cleaning as a robust compromise between energy recovery, maintenance cost, and water conservation, offering practical guidance for optimizing PVT deployment in water-scarce desert regions.