.IDEAS.Fluid.PVTCollectors.Validation.PVT_UN.PVT_UN_Thermal

Information

This model validates the thermal performance of the PVT_UN collector, an uncovered and uninsulated PVT collector, using a long-term dataset from a test bench in Austria (Veynandt et al., 2023).

The model uses the quasi-dynamic ISO 9806 formulation and includes:

• Linear and quadratic heat losses (c1, c2)
• Wind-dependent convective losses (c3, c6)
• Radiative losses based on sky temperature (c4)
• Thermal inertia (c5)

The dataset includes days with several hours of high wind speeds up to 10–12 m/s, which significantly increase convective losses. Additionally, the circulation pump remains active throughout the test period, even when thermal output is negative—unlike real-world systems, which would deactivate the pump under such conditions.

As a result, the raw energy deviation of +53.1 % is not a meaningful indicator of model performance. When filtered to periods with positive simulated thermal output, the deviation improves to +6.85 % (Meertens et al., 2025). This filtered metric better reflects the model's accuracy under realistic operating conditions.

Contents

Revisions

• September 3, 2025, by Jelger Jansen:
  Introduce week parameter to change the weather dataset. This is for #1462.
• July 7, 2025, by Lone Meertens:
  First implementation PVT model. This is for #1436.