Close Roof Mounted System Temperature Estimation for Compliance to IEC TS 63126

Michael Kempe, Silvana Ovaitt, Martin Springer, Matthew Brown, Dirk Jordan, William Sekulic, Colleen O'Brien, Jean-Nicholas Jaubert, Yuanjie Yu, Jaewon Oh, Govindasamy Tamizhmani, Bo Li

Research output: NRELPoster


When photovoltaic modules are installed on rooftops the temperature is dependent on both the geographic location and the mounting configuration. If the mounting structure does not provide sufficient air flow in a hot environment, the 98th percential temperature will exceed 70 degrees C which according to IEC TS 63126 requires higher levels of thermal stability testing. However, a simple there is not a clear way to determe which temperature level is needed for a particular location and system design. In this work we identify a relationship between the gap between the rooftop and a module and propose methods to describe minimum gaps for a given location. Because system designs vary in more ways than just the gap, we show how to determine an effective gap which can be simply applied to generic calculations. Lastly, we show measurements and calculations from several systems to demonstrate how this method could work.
Original languageAmerican English
StatePublished - 2023

Publication series

NamePresented at the 50th IEEE Photovoltaic Specialists Conference, 11-16 June 2023, San Juan, Puerto Rico

NREL Publication Number

  • NREL/PO-5K00-85093


  • IEC 63126
  • photovoltaics
  • temperature model


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