Development and Experimental Validation of an Unglazed Photovoltaic-Thermal Collector Modelica Model that only needs Datasheet Parameters

Abstract

This work introduces the first validated, user-friendly,and accurate open-source photovoltaic-thermal (PVT)collector model in Modelica, tailored for system-levelsimulation and optimization. Current state-of-the-art PVTcollector Modelica models are largely limited tooversimplified, steady-state representations that fail tocapture the dynamic thermal behavior inherent to real PVTsystems. A comprehensive Modelica model is developed basedon the ISO 9806 standard (test method for the quasi-dynamicthermal performance of solar thermal collectors), coupledwith an electrical system model through an internal heattransfer coefficient. The model calibration reliesexclusively on manufacturer datasheet parameters, therebyeliminating the need for parameter estimation frommeasurement data. The model is validated using experimentalresults from an unglazed PVT collector, demonstratingstrong agreement for various (weather) conditions. Thefindings highlight that, while steady-state models maysuffice for conventional solar thermal collectors (STCs),accurate PVT modeling necessitates a dynamic approach,particularly for the thermal aspects. The electrical outputof the PVT collector is less sensitive to transienteffects. In addition to the model formulation andvalidation, this work presents a user-friendly automatedcalibration method based on manufacturer data, andcritically addresses the limitations and potentialtrade-offs of using exclusively datasheet-derivedparameters, thereby providing a transparent tool for PVTsystem simulation, design, and optimization within theopen-source IDEAS library.