Introduction
The efficiency of solar panel in desertified regions is significantly compromised by dust accumulation, a challenge exacerbated by frequent wind-sand interactions. This study employs computational fluid dynamics (CFD) to simulate dust deposition patterns on solar panel under varying installation angles, dust concentrations, and particle sizes. By analyzing the relationship between dust accumulation and light transmittance, this work provides critical insights for optimizing solar panel installations in arid environments.
Numerical Model and Methodology
The three-dimensional flow field around solar panel was simulated using the k-ε turbulence model within ANSYS Fluent. The governing equations for incompressible flow are:
Continuity Equation:∂ui∂xi=0∂xi∂ui=0
Momentum Equation:∂(ρui)∂t+∂(ρuiuj)∂xj=−∂p∂xi+∂∂xj(μ∂ui∂xj−ρui′uj′‾)∂t∂(ρui)+∂xj∂(ρuiuj)=−∂xi∂p+∂xj∂(μ∂xj∂ui−ρui′uj′)
Turbulent Kinetic Energy (kk) Equation:∂(ρk)∂t+∂(ρkuj)∂xj=∂∂xj[(μ+μtσk)∂k∂xj]+Gk−ρϵ∂t∂(ρk)+∂xj∂(ρkuj)=∂xj∂[(μ+σkμt)∂xj∂k]+Gk−ρϵ
Dissipation Rate (ϵϵ) Equation:∂(ρϵ)∂t+∂(ρϵuj)∂xj=∂∂xj[(μ+μtσϵ)∂ϵ∂xj]+C1ϵϵkGk−C2ϵρϵ2k∂t∂(ρϵ)+∂xj∂(ρϵuj)=∂xj∂[(μ+σϵμt)∂xj∂ϵ]+C1ϵkϵGk−C2ϵρkϵ2
The Eulerian multiphase model was applied to simulate sand-particle transport. Boundary conditions included a logarithmic velocity profile at the inlet:U=u∗κlnyz0U=κu∗lnz0y
where u∗=0.3 m/su∗=0.3m/s, κ=0.41κ=0.41, and z0=0.025 μmz0=0.025μm.
Dust deposition mass (MsMs) on solar panel was calculated as:Ms=ρsand×∫Nh dAMs=ρsand×∫NhdA
where ρsand=2650 kg/m3ρsand=2650kg/m3, NN = particle number density, and hh = grid height.
Light transmittance (TT) through dusty solar panel followed the modified Lambert-Beer law:T=exp(−3(1−β)Ms4ρsandrv)T=exp(−4ρsandrv3(1−β)Ms)
Here, β=0.45β=0.45 (sand transparency factor) and rvrv = equivalent particle radius.
Key Findings
1. Impact of Installation Angle
The installation angle of solar panel critically influences dust accumulation and flow separation. At 50°, maximum dust deposition occurs due to enhanced vortex formation on the panel’s leeward side (Table 1).
Table 1: Dust Deposition and Transmittance vs. Installation Angle
| Installation Angle (°) | Dust Deposition (kg/m²) | Light Transmittance (%) |
|---|---|---|
| 25 | 0.12 | 88 |
| 35 | 0.24 | 82 |
| 50 | 0.35 | 70 |
| 75 | 0.21 | 79 |
2. Effect of Dust Concentration and Particle Size
Dust deposition increases exponentially with particle size and volume fraction. For instance, doubling the particle size from 10 µm to 20 µm quadruples deposition mass.
Table 2: Dust Deposition vs. Particle Size and Volume Fraction
| Particle Size (µm) | Volume Fraction (%) | Dust Deposition (kg/m²) |
|---|---|---|
| 10 | 5×10−45×10−4 | 0.15 |
| 20 | 5×10−45×10−4 | 0.62 |
| 30 | 5×10−45×10−4 | 1.40 |
| 10 | 5×10−35×10−3 | 1.20 |
3. Flow Field Characteristics
- Low Angles (25°–35°): Wind velocity gradients along solar panel is gradual, leading to uniform dust layers.
- High Angles (>50°): Turbulent vortices dominate, causing non-uniform dust distribution and localized accumulation.
Discussion
Optimizing Solar Panel Performance
- Installation Angle: Avoid 50° in high-dust regions to minimize efficiency loss. Angles below 35° or above 65° reduce deposition.
- Particle Size Mitigation: Coarse particles (>30 µm) contribute disproportionately to transmittance loss. Protective coatings or frequent cleaning are recommended.
- Regional Adaptability: In deserts with fine dust (≤10 µm), tilt angles above 60° may reduce deposition due to higher wind scouring.
Table 3: Recommended Installation Strategies
| Region Type | Optimal Angle (°) | Cleaning Frequency |
|---|---|---|
| Coarse Dust Dominant | 25–35 | Biweekly |
| Fine Dust Dominant | 60–75 | Monthly |
Conclusion
This study demonstrates that dust accumulation on solar panel is governed by installation angle, particle size, and environmental dust concentration. Key takeaways include:
- Maximum dust deposition occurs at 50° tilt, reducing light transmittance by up to 30%.
- Exponential increases in deposition correlate with particle size and airborne dust concentration.
- Strategic angle adjustments and particle-size-specific maintenance can enhance solar panel efficiency in arid regions.
Future work will explore dynamic dust-redistribution mechanisms and anti-soiling coatings to further mitigate efficiency losses.