pvperfsolar performance modeling

Reference

API field

SAPM coefficient a

The SAPM temperature coefficient at no wind; empty = King's table

Unit –

What it is

The coefficient a of King's Sandia (SAPM) temperature model, the natural logarithm of the module's temperature rise per W/m² at no wind. Used only by the SAPM model. Give a, b and ΔT together. If not given, all three come from King's table by racking and module: open rack glass/glass (a −3.47, b −0.0594 s/m, ΔT 3 °C) for bifacial modules on fixed racks and trackers, open rack glass/polymer (−3.56, −0.0750 s/m, 3 °C) for monofacial modules, and close roof mount glass/glass (−2.98, −0.0471 s/m, 1 °C) on rooftop racking.

Typical values and how to get it

Leave it empty for King's table. Enter a measured fit, or another row of King's table, such as insulated back glass/polymer (−2.81, −0.0455 s/m, 0 °C) for a building-integrated array.

References

  1. King, Boyson & Kratochvil 2004, Photovoltaic Array Performance Model, Sandia report SAND2004-3535
  2. pvlib-python 0.16.1 source code (github.com/pvlib/pvlib-python), reference implementation: pvlib/temperature.py, sapm_cell() and fuentes()

API

thermal.sapm_a