Energy Characterization and Optimization of New Heat Recovery Configurations in Hybrid PVT Systems

The main goal of this research is to design and assess a new heat recovery (absorber-exchanger) configuration for a hybrid PVT solar panel with a geometry and from a material that maximises heat transfer while reducing weight and cost. To this end, firstly, potential configurations and materials for the absorber-exchanger unit that have the potential to meet the aforementioned aim are considered. The selected configurations (plus a benchmark reference case) are then applied to the same PVT panel in order to compare their performance. Once these configurations are defined in detail, they are modelled in 3-D finite-element and multiphysics (FEM and CFD) software, specifically COMSOL. The objectives are to: i) maximize the heat transfer performance of the different absorber-exchanger configurations, ii) obtain characteristic curves that describe the steady-state performance of the PVT panel in each case, and iii) compare the different alternatives with the reference case. The results show that a polymeric flat-box configuration is a promising alternative to commercial PVT panels, being able to achieve an improvement in the thermal performance of the PVT unit compared to the reference case (up to 5.1% higher optical efficiency and up to 48.7% lower heat loss coefficient), while also lowering the weight (up to 12%) and investment costs (up to 22%) of the PVT panel.