Sand particle deposition and re-suspension characteristics of PV modules and the effects on PV efficiency: based on CFD-DEM simulation

Solar energy, as a kind of important renewable energy source, has been developed rapidly in recent years. However, the efficiency of photovoltaic (PV) power generation is not high due to particle deposition, especially in desert area. For better understanding the dust deposition and re-suspension characteristics of PV modules, a multi-physics field model considering particle deposition and re-suspension is developed using a coupled CFD-DEM method. The processes of collision, rolling, deposition, bounce and re-suspension of particles on the PV module are considered in the simulation. A total of 20 kinds of cases are developed in the simulation. The results show that the sand particles located around the PV panels are firstly removed after wind blowing. Vin = 5.2 m/s, can effectively clean particles with dp ≤ 200 μm, removal rate δ ≥ 42.3 %. Vin = 7.8 m/s can effectively clean particles with dp ≤ 500 μm, and the removal rate δ ≥ 50.6 %. And the reduction of PV efficiency varied significantly with increasing inlet velocity, Vin = 2.6, 5.2, 7.8 m/s, η is 6.60 %, 5.61 % and 2.86 %, respectively. For particle size with 100 μm ≤ dp ≤ 500 μm, evaluated by PV maximum output power, a higher inlet velocity leads to a better removal effect, particularly for larger sand particles. Based on the reduction of PV efficiency evaluation, it is shown that the larger the inlet velocity, a smaller particle size leads to a smaller η value and the a cleaning effect.