Snow shedding is encouraged when landscape-oriented panels are positioned on horizontal rails, rather than vertical ones, according to a whitepaper from Solar FlexRack.
A new whitepaper finds that panel and racking orientation makes a difference when it comes to snow buildup on solar arrays.
Solar FlexRack’s latest whitepaper suggests that mounting landscape-oriented panels on vertical rails instead of horizontal can expedite snow load shedding. A field trial between the company’s own vertical design and a competitor’s horizontal setup showed a significant difference in show shedding ability.
Landscape-mounted panels are typically used in snowy areas because snow accumulation at the bottom of portrait-oriented panels leads to greater energy production losses due to panel-cell interconnection.
The time an array takes to shed snow is important because snow cover impacts energy production and the resulting economic performance of an array. While solar is known to perform better in chilly environments, snow cover can be problematic. (Read about the performance impact of snowfall here.)
The Solar FlexRack study explains that the gaps between panels mounted on vertical rails lets snow melt or shed and freely drop to the ground—each panel shedding its own snow. When panels are mounted to horizontal rails, however, the mounting system itself bridges those gaps. As a result, the snow drops or melts into the channel between panels, solidifies or re-freezes, blocking drainage. The blockage becomes an anchor for the layers or sheets of snow that can only shed to the bottom of the rack.
Because the snow takes more time to shed, further buildup is likely, exasperating the problem and increasing the chance of design load limits being exceeded, which could lead to structural failure.
In addition, partial shading of panels causes hot spots which can cause an acceleration in the degradation of panel materials. Minimizing snow shading decreases this potential damage. The whitepaper says the following are a result of Solar FlexRack’s mounting architecture:
- Significant difference in energy production over winter months.
- Horizontal mount racks have a greater chance of exceeding their design static load limit, increasing the chances of structural failure.
- Minimizing snow shading decreases cell and panel degradation due to hot spots.