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Summary

When measured back-of-module surface temperature data is available as a time series, it can be used directly in place of a temperature model. This option overrides the selected temperature model (Heat Balance, Sandia, or NOCT-SAM) and derives cell temperature from the measured back-of-module surface temperature using the standard irradiance-proportional offset.

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Inputs

NameSymbolUnitsDescription
Measured Surface TemperatureTm,measuredT_{m,measured}°CBack-of-module surface temperature from time-series data
Effective Front POA IrradianceGPOA,front,effG_{POA,front,eff}W/m²Front-side POA irradiance after optical corrections, before DC system losses (from irradiance calculation)
Cell-to-Module Temp DifferenceΔTc−m\Delta T_{c-m}°CTemperature difference between cell and module surface at reference irradiance
Reference IrradianceGrefG_{ref}W/m²Reference irradiance (typically 1000 W/m²)

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Outputs

NameSymbolUnitsDescription
Cell TemperatureTcT_c°COperating temperature of PV cells
Surface TemperatureTmT_m°CBack-of-module surface temperature (from time series)

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Detailed Description

The measured back-of-module surface temperature is used directly. For each time step: Tm=Tm,measuredT_m = T_{m,measured} Cell temperature is derived by adding the standard irradiance-proportional offset: Tc=Tm+GPOA,front,effGref⋅ΔTc−mT_c = T_m + \frac{G_{POA,front,eff}}{G_{ref}} \cdot \Delta T_{c-m} where:
  • TmT_m is the measured back-of-module surface temperature (from time-series data)
  • GPOA,front,effG_{POA,front,eff} is the front-side after optical corrections, before DC losses, in W/m² (from irradiance calculation)
  • GrefG_{ref} is the reference irradiance in W/m² (from module definition, typically 1000 W/m²)
  • ΔTc−m\Delta T_{c-m} is the cell-to-module temperature difference at the reference irradiance, in °C (from DC field definition)
This cell-temperature derivation uses the same formula as the Sandia model. To use this model, the user must both upload surface temperature time series and assign these time series to their respective DC fields.