packageThermal

Thermal Behavior of Unglazed Rear-Insulated PVT Collector

Information

This subpackage contains four validation models for the thermal performance of the PVT_UI collector, an uncovered PVT collector with rear insulation. The models correspond to the four ISO 9806:2013 day types:

  • Day Type 1: Clear sky, low temperature difference (η0 conditions)
  • Day Type 2: Partly cloudy, low temperature difference
  • Day Type 3: Clear sky, medium temperature difference
  • Day Type 4: Clear sky, high temperature difference

Each model compares the simulated thermal output with measured data and provides a detailed breakdown of thermal losses using the quasi-dynamic ISO 9806 formulation. The following loss mechanisms are included:

  • Linear and quadratic heat loss (c1, c2)
  • Convective heat loss (wind-dependent, c3, c6)
  • Radiative heat loss (sky temperature dependent, c4)
  • Thermal inertia effects (c5)

The model is discretized into nSeg segments to capture temperature gradients along the flow path. All parameters are derived from manufacturer datasheets, without calibration.

Validation results show strong agreement for day types 1–3, with thermal energy deviations below 4.2 % and normalized MAE values ranging from 3.3 % to 20.0 %. For day type 4, larger deviations (ΔE = 36.7 %) are observed due to high temperature differences and wind speeds, highlighting limitations in the datasheet-based coefficients under extreme conditions. As the absolute thermal output is low in this case, model limitations have a stronger effect, leading to disproportionately large relative deviations (Meertens et al., 2025).

References

  • Meertens, L., Jansen, J., Helsen, L. (2025). Development and Experimental Validation of an Unglazed Photovoltaic‑Thermal Collector Modelica Model that only needs Datasheet Parameters, submitted to the 16th International Modelica & FMI Conference, Lucerne, Switzerland, Sep 8–10, 2025.
  • ISO 9806:2013. Solar thermal collectors — Test methods. ISO.

Contents

NameDescription
PVT_UI_Thermal_DayType1Test model for Unglazed Rear-Insulated PVT Collector
PVT_UI_Thermal_DayType2Test model for Unglazed Rear-Insulated PVT Collector
PVT_UI_Thermal_DayType3Test model for Unglazed Rear-Insulated PVT Collector
PVT_UI_Thermal_DayType4Test model for Unglazed Rear-Insulated PVT Collector

Revisions

  • July 7, 2025, by Lone Meertens:
    First implementation PVT model. This is for #1436.