Cleaning solar panels at the right time is essential to maintain their efficiency and prolong their lifespan. The best time to clean solar panels depends on several factors, including the time of day, weather conditions, and the specific cleaning method being employed. Here’s a detailed breakdown to help you choose the optimal cleaning time:
Time of Day
1. Early Morning or Late Night
Reasons: Early morning or late night are generally the coolest parts of the day, preventing thermal shock to the solar panels. Cleaning during these hours also avoids disrupting power production as the panels are not generating electricity.
Benefits:
- Cooler temperatures reduce the risk of water evaporating too quickly, leaving mineral deposits and streaks on the panels.
- Minimal sunlight means less glare, facilitating thorough cleaning.
2. Avoid Midday
Reasons: Midday features the sun at its highest, generating the most electricity and increasing the risk of thermal shock from cold water use.
Risks:
- Rapid evaporation can lead to uneven cleaning and water spots.
- High temperatures may make the cleaning process less effective and hazardous.
Weather Conditions
1. Clear Skies
Best Time: Early morning or late night on clear days to maximize benefits of cool temperatures and visibility.
2. Overcast Days
Best Time: Any time during the day, but early morning or late night remains preferable for consistency and comfort during cleaning.
3. Rainy Days
Best Time: Avoid cleaning unless panels are severely contaminated and rain is insufficient for proper cleaning, as the surface can be slippery.
4. Dusty or Sandy Conditions
Best Time: Clean as soon as possible after a dust or sand event, ideally during the cooler hours of early morning or late night to mitigate efficiency loss.
Cleaning Method
1. Water-Based Cleaning
Best Time: Early morning or late night to ensure water does not evaporate too quickly.
2. Dry Cleaning (Brushes, Blowers)
Best Time: Preferably during cooler hours to avoid high temperatures and direct sunlight.
3. Automated Cleaning Systems
Best Time: Most automated systems operate during off-peak hours (early morning or late night) for optimal efficiency.
Practical Examples
1. Guangzhou Development New Energy Co., Ltd.
- Cleaning Schedule: They maximize economic benefits by cleaning rooftop solar panels every 7 weeks.
- Best Time: Likely performed in cooler hours to avoid thermal shock.
2. Huadian Zhejiang Clean Energy Branch
- Pollution Categories: They categorize solar panels into light, moderate, and severe pollution.
- Frequency:
- Light Pollution: Cleaned annually.
- Moderate Pollution: Cleaned every 6 months.
- Severe Pollution: Cleaned every 4 months.
- Best Time: Consistently during the cooler hours for all categories.
Conclusion
The best time to clean solar panels is during the cooler hours of early morning or late night, regardless of the cleaning method. This timing helps prevent thermal shock, ensures thorough cleaning, and minimizes disruption. Consider weather conditions and specific needs for further optimization. For automated systems, programming to clean during these optimal times enhances effectiveness and longevity.
Please refer to the detailed calculation method：Calculation Formulas for Photovoltaic Power Plant Cleaning Effects and Intervals
