Vertical packing is the stacking of PV modules on vertical racks in a shipping trailer or container. The key features are: Rail & Hinge Systems: Heavy-duty rails transport panels; rugged hinges allow panels to swing or slide out.
Horizontal installation is traditionally preferred on rooftops due to simpler cabling and lower wind load, while vertical installation performs better in drainage and architectural integration.
As a rule of thumb, solar panels should be more vertical during winter to gain most of the low winter sun, and more tilted during summer to maximize the output.