Double-diffusive natural convection with Soret/Dufour effects and energy optimization of Nano-Encapsulated Phase Change Material in a novel form of a wavy-walled I-shaped domain

Background: As building segment grows in parallel with amplifying population, the necessity for consumption of energy needed to passive and active heating or cooling buildings for thermal comfort increases. Schemes such as developing green buildings for sustainable architecture were utilized to address this issue. The utilization of Phase Change Materials (PCMs) with the aim of active and passive cooling or heating of buildings illustrates a promising and modern technique. Methods: This study's objective is to perform a numerical analysis using the finite element method, FEM for modeling free convection produced by double-diffusion (DDNC) with Soret/Dufour effects of Nano-Encapsulated PCMs within an I-shaped enclosure equipped with a novel type of corrugated vertical walls subjected to Neumann thermal and solutal conditions. Findings: Results are interpreted and assessed in relation to the governing factors, such as buoyancy ratio (N), Rayleigh and Lewis numbers (Ra, Le), the height of corrugated walls (a), Stefan number (Ste), non-dimensional fusion temperature (θf), Dufour (Df), and Soret (Sr) parameters. High values of N and Ra, and low values of Le and a, caused in the highest rate of heat and mass exchange. The irreversibilities due to the heat and mass transfer effects increase as the flow intensity within the system decrease. Decreasing the latent heat of the NEPCM cores and increasing their fusion temperature lowering the heat transfer rates, while improving mass transfer rates. This configuration can help in the design of the storage tank in hydronic apparatus for cooling, heating, and domestic hot water in buildings.