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Control strategies for melting snow on PV modules

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This page is the basic outline for control strategies for removing snow from PV modules in northern climates using a heating mechanism to melt the snow. Why is this a problem? See Effects of snow on photovoltaic performance and Impact of Snow and Ground Interference on Photovoltaic Electric System Performance

Potential Inputs[edit]

Sensor inputs for determining snow cover

  • temperature
  • snow depth via sensor
  • optical occlusion
  • optical reflection from modules
  • force sensor
  • module image
  • off-site weather data/ past and/or predicted
  • reduced PV output as compared to heated (always on) pyranometer
  • IR sensing
  • wireless/wired connection to web server that has current weather information (also a dispatch strategy)
  • certain decrease in panel output power

Potential Outputs[edit]

Electrical resistive heating using one of the following methods:

  • heat strips on back of panel
  • heat strips on edges of panel
  • electrically conductive optically transparent front retrofit of panel
  • electrically conductive optically transparent front integrated panel (e.g. top layer of glass, in eva, etc.)
  • external heater
  • liquid heating on edges of panel
  • liquid heating underneath panel
  • mechanical clearing
  • compressed air, air blast clearing
  • chemical release -- e.g. salt solution

Potential Dispatch Strategies[edit]

  • always on
  • manual on/off
  • on every morning, or other set amount of days
  • melt while snowing
  • melt every snow fall
  • melt on predetermined time -- dynamic so changes during snow season based on historical data or current weather trends
  • melt on predetermined depth or weight of snow or optical occlusion
  • change as a function of time, temperature, output, solar flux
  • wireless/wired connection to web server that has current weather information (also an input strategy)
  • dependent upon amount of panel output power