Summary
Module Temperature Models calculate the operating cell temperature of photovoltaic modules based on environmental conditions and effective irradiance. Cell temperature is a critical input to the DC performance models, as module electrical output decreases with increasing temperature. PlantPredict implements three temperature models:| Model | Description |
|---|---|
| Heat Balance (Default) | Physics-based model using conductive and convective heat transfer coefficients |
| Sandia | Empirical exponential model developed at Sandia National Laboratories |
| NOCT-SAM | Scales from Nominal Operating Cell Temperature with wind and mounting adjustments |
Common Inputs
All models use these common inputs:| Name | Symbol | Units | Description |
|---|---|---|---|
| Ambient Air Temperature | °C | Dry-bulb air temperature | |
| Wind Speed | m/s | Wind velocity | |
| Effective POA Irradiance | W/m² | Effective irradiance after all optical losses | |
| Cell-to-Module Temp Diff | °C | Temperature difference between cell and module surface |
Common Outputs
All models produce these outputs:| Name | Symbol | Units | Description |
|---|---|---|---|
| Cell Temperature | °C | Operating temperature of PV cells | |
| Surface Temperature | °C | Module surface (back-of-module) temperature |
Model Selection
The choice of temperature model depends on available data and modeling requirements:- Heat Balance (Default): Recommended when module-specific heat transfer coefficients are available. Provides physics-based results. Aligned with PVsyst.
- Sandia: Recommended when Sandia a/b coefficients are available from module characterization. Well-validated empirical model.
- NOCT-SAM: Recommended when only NOCT is available. Accounts for mounting configuration effects.
References
- King, D. L., Boyson, W. E., & Kratochvil, J. A. (2004). Photovoltaic array performance model. SAND2004-3535, Sandia National Laboratories.
- Faiman, D. (2008). Assessing the outdoor operating temperature of photovoltaic modules. Progress in Photovoltaics: Research and Applications, 16(4), 307–315.
- Gilman, P., et al. (2018). SAM photovoltaic model technical reference update. NREL/TP-6A20-67399, National Renewable Energy Laboratory.