.IDEAS.Fluid.PVTCollectors.Validation.PVT_UN

Information

This package contains validation models for the PVT_UN collector (referred to as PVT2 in Meertens et al., 2025), an uncovered and uninsulated PVT collector, based on experimental data from a long-term outdoor test campaign in Austria (Veynandt et al., 2023).

The full dataset spans 58 consecutive summer days with 5-second resolution, capturing a wide range of operating conditions. Notably, the test period includes days with several hours of very high wind speeds, reaching up to 10–12 m/s, which significantly affect convective heat losses.

The full dataset was split into 8 weeks to limit the file size per dataset. The validation models allow to change the week via the parameter week. The user can also merge the files together into one dataset and change the fileName parameter in the meaDat block to simulate the all 58 summer days in one run.

The package includes two models:

• Thermal: Validates thermal output using the quasi-dynamic ISO 9806 formulation.
• Electrical: Validates electrical output using the PVWatts V5 formulation.

Due to the absence of rear insulation and the continuous operation of the circulation pump, also during periods of negative thermal output, the raw energy deviation of +53.1 % is not representative of real-world operation. In practice, the pump would only be activated when thermal gains exceed losses. When filtered to periods with positive thermal output, the deviation improves to +6.85%. This filtered metric provides a more meaningful assessment of the model performance.

The electrical model shows excellent agreement with measurements, with a normalized MAE of 5.2% and nRMSE of 9.9%. The model is robust to variations in UAbsFluid, confirming the reliability of the datasheet-based estimation method.

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
• Veynandt, François, Franz Inschlag, et al. Measurement data from real operation of a hybrid photovoltaic‑thermal solar collectors, used for the development of a data‑driven model. Data in Brief 49 (2023): 109417. DOI: 10.1016/j.dib.2023.109417
• Veynandt, François, Peter Klanatsky, et al. Hybrid photovoltaic‑thermal solar collector modelling with parameter identification using operation data. Energy and Buildings. 295 (2023): 113277. DOI: 10.1016/j.enbuild.2023.113277

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