Challenges in BiPV/PCM Façade System: Pathways Towards Numerical Modelling and Simulation Approaches

Simulation modelling of heat and mass transfer processes is conducted in the case of a special type of a building integrated photovoltaic (BiPV) façade system with latent thermal energy storage (LTES) based on a phase change material (PCM). Experimental and simulation models are developed as part of the ventilated façade system for it to analyze and verify the adequacy of the available simulation tools. The key aspect of a BiPV/PCM façade concept is focused on reducing the peak operating temperatures of the PV modules and affecting action-reaction processes involving heat and mass transfer changes inside the façade elements. Experimental measurements were performed using an outdoor test cell to verify and validate numerical models. A comparative investigation of two façade concepts (BiPV, BiPV/PCM) is conducted using two simulation domains: the BES method (EnergyPlus) and the numerical CFD method (Ansys). The heat transfer rate through all façade elements is influenced by the high thermal inertia of the PCM differently in the diurnal/nocturnal period. The dynamic thermal response function of this façade system changes concerning the climate conditions at a small timescale (reactivity). The experimental measurements and simulation results are compared for it to provide an insight into consistency between the theoretical results and the experimental data. However, this indicates several limitations that need to be properly identified for further design.