Winter Solstice Row Spacing (Anti-Shading Pitch)
Core Question: How do you calculate the minimum row-to-row spacing between solar arrays to prevent inter-row shading on the shortest day of the year?
Executive Technical Summary
Array row spacing must be sized for 9:00 AM to 3:00 PM solar window on the Winter Solstice (December 21 in Northern Hemisphere). The solar elevation angle reaches its annual minimum, casting the longest shadows.
Detailed First-Principles Explanation
Inter-row shading causes localized bypass diode activation, dropping entire string voltage and creating severe thermal stress. In mid-latitudes (35°N~45°N), the row pitch is typically 2.2 to 2.8 times the vertical module height to ensure 100% unshaded generation during peak mid-day production.
Never squeeze extra rows onto a flat roof without verifying Winter Solstice 9AM shadow length; the bottom 5cm of morning shade can wipe out 30% of string power.