Model step
Cell temperature
Cell temperature
Inputs used: Thermal loss factor Uc (constant), Thermal loss factor Uv (wind), Absorptivity, Thermal inertia, Module unit mass, NOCT standoff adjustment, SAPM coefficient a, SAPM coefficient b, SAPM ΔT, CEC database parameters, Racking type, Ambient temperature, Wind speed
What it is
A module runs warmer than the air, and a warmer module produces less power. This step computes the cell temperature from the light the module absorbs, the ambient temperature and the wind. How well the mounting lets the module shed heat enters as heat-loss factors or as a nominal operating cell temperature, depending on the option.
Options
- Prilliman transient: Faiman's heat balance with the module's actual efficiency, then Prilliman's transient weighting
- Faiman: Faiman's heat balance with the rated efficiency and no thermal lag
- NOCT (Duffie and Beckman): the rise above the air at nominal operating conditions, scaled by irradiance and wind
- NOCT, module's rated NOCT: the NOCT model with the module's rated NOCT and a standoff adjustment
- SAPM (King 2004): King's Sandia model: the module back temperature, then a conduction step to the cells
- Fuentes: Fuentes's heat balance with the module's heat capacity
References
- Faiman 2008, Assessing the outdoor operating temperature of photovoltaic modules, Progress in Photovoltaics 16(4) 307–315
- Prilliman, Stein, Riley & Tamizhmani 2020, Transient weighted moving-average model of photovoltaic module back-surface temperature, IEEE Journal of Photovoltaics 10(4) 1053–1060
- Duffie & Beckman, Solar Engineering of Thermal Processes, 4th ed., Wiley 2013
API
thermal.model = prilliman | faiman_steady | noct | noct_module | sapm | fuentes, thermal.transient = true | false, thermal.noct_standoff_adjust_c, thermal.sapm_a, thermal.sapm_b, thermal.sapm_delta_t