Quick Answer
East-facing solar arrays typically produce 10-15% more energy than west-facing arrays during the summer months in the Northern Hemisphere, but east-facing arrays produce less energy during the winter months.
Choosing the Optimal Azimuth
When it comes to deciding between an east- or west-facing solar array, the optimal orientation depends on the climate and location. In general, east-facing arrays tend to produce more energy during the summer months, while west-facing arrays produce more energy during the winter months.
Calculating Azimuth for Specific Regions
To determine the optimal azimuth for a specific location, consider the solar declination angle, which varies throughout the year. For example, in the Northern Hemisphere, the solar declination angle is at its most negative (22.5°) in the winter months and at its most positive (23.5°) in the summer months. By comparing the solar declination angle to the latitude of the location, we can determine the optimal azimuth angle. A general rule of thumb is to orient the array at an angle equal to the latitude plus 15° to 20°. For example, in San Francisco, California (37.8° latitude), a 52.8° to 57.8° azimuth angle would be optimal.
Practical Considerations
While the optimal azimuth angle can be calculated, practical considerations such as shading, wind direction, and property lines may also influence the final orientation. It’s essential to consult with a solar professional to ensure the array is properly sized and oriented for optimal performance. Additionally, some solar inverters and monitoring systems can help optimize the array’s performance by adjusting the azimuth angle based on real-time solar irradiance data and other environmental factors.
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