CFD Modelling for the Design of a Photovoltaic-Thermal Solar Panel Dedicated to Solar-Assisted Heat Pump

A sustainable and cost-effective solution for space heating and domestic hot water supply is a heat pump system with Photovoltaic-Thermal (PVT) collectors as its sole heat source. This paper is part of a drive to optimise the design of these collectors to go one step further. To maximise heat transfer from the ambient air at night, a better understanding of the air flows, both free and forced convection, around the panel was crucial. We developed a Computational Fluid Dynamics (CFD) model using ANSYS Fluent to replicate and analyse the thermal behaviour of PVT panels when tested on a standard indoor test bench without irradiation. It demonstrated robust predictive capacity, estimating the thermal power output within 15% of experimental data. Three designs were selected for simulation following a preliminary stage based on a 1D-2D thermal performance numerical model with hydraulic and manufacturing feasibility constraints. The validated CFD model enabled an in-depth investigation of how different design elements, such as contact points, corrugations, and fins, influence the overall thermal efficiency, temperature distribution, and heat transfer characteristics. This CFD model was used to select the optimal design among our concepts. Besides, it allowed for a better understanding of the impact of the complete PVT panel geometry on the convection airflow, of the behaviour of the test bench itself, and provided heat transfer coefficient laws as inputs for the 1D-2D model referenced above.