Skip to main content

​
Summary

Temperature Coefficients define how module parameters vary with operating temperature. PlantPredict applies temperature coefficients during parameter translation from Standard Test Conditions to actual operating conditions. The primary coefficients are: short-circuit current temperature coefficient (αIsc\alpha_{I_{sc}}), diode ideality factor temperature coefficient (αγ\alpha_{\gamma}), and series resistance temperature coefficient (αRs\alpha_{R_s}). Temperature coefficients are typically provided by manufacturers in module datasheets and are critical for accurate performance modeling across seasonal temperature variations.

​
Inputs

NameSymbolUnitsDescription
Isc Temperature CoefficientαIsc\alpha_{I_{sc}}1/K or %/°CLinear temperature dependence of short-circuit current
Gamma Temperature Coefficientαγ\alpha_{\gamma}1/KLinear temperature dependence of ideality factor
Rs Temperature CoefficientαRs\alpha_{R_s}1/KLinear temperature dependence of series resistance
Reference TemperatureTrefT_{ref}KReference temperature (typically 298.15 K)
Actual TemperatureTactualT_{actual}KOperating cell temperature

​
Outputs

NameSymbolUnitsDescription
Scaled IscIscI_{sc}ATemperature-scaled short-circuit current
Scaled Gammaγ\gamma—Temperature-scaled ideality factor
Scaled RsRsR_sΩTemperature-scaled series resistance

​
Detailed Description

​
Short-Circuit Current Temperature Coefficient

Applied in IscI_{sc} scaling: Isc=Isc,refGactualGref(1+αIsc(Tactual−Tref))I_{sc} = I_{sc,ref} \frac{G_{actual}}{G_{ref}} (1 + \alpha_{I_{sc}} (T_{actual} - T_{ref})) Typical values: αIsc=0.0003\alpha_{I_{sc}} = 0.0003 to 0.00060.0006 /K for crystalline silicon.

​
Ideality Factor Temperature Coefficient

Applied in γ\gamma scaling (linear model): γ=γref(1+αγ(Tactual−Tref))\gamma = \gamma_{ref} (1 + \alpha_{\gamma} (T_{actual} - T_{ref}))

​
Series Resistance Temperature Coefficient

Applied in RsR_s scaling: Rs=Rs,ref(1+αRs(Tactual−Tref))R_s = R_{s,ref} (1 + \alpha_{R_s} (T_{actual} - T_{ref})) In PlantPredict implementation: αRs=0\alpha_{R_s} = 0 (not used).

​
References

  • King, D. L., Boyson, W. E., & Kratochvil, J. A. (2004). Photovoltaic array performance model. SAND2004-3535, Sandia National Laboratories.
  • IEC 61215:2021. Terrestrial photovoltaic (PV) modules – Design qualification and type approval.