Numerical study on PCM geometries to enhance thermal performance of building envelopes

This research focuses on the thermal performance of construction walls with PCMs in a moderate climate, the main aim being the improvement of passive temperature control and a decrease in energy resource requirements. The main aim is to investigate the transient response of temperature distribution and PCM state change (in terms of liquid fraction) within the wall. The transient numerical simulation was performed using ANSYS Fluent based on enthalpy method to capture latent heat storage and subsequent release due to phase-change. Characteristic parameters under investigation are the temperature distribution across the wall layers as well as the liquid fraction of the PCM during charging and discharging. Different PCM categories and melting points were considered to give evidence regarding advantageous thermal performance. A high-resolution simulation setup for the boundary conditions of a moderate climate is employed, and what is new is that both thermal and phase transition physics are considered. Characteristic parameters under investigation are the temperature distribution across the wall layers as well as the liquid fraction of the PCM during charging and discharging. Different PCM categories and melting points were considered to give evidence regarding advantageous thermal performance. A high-resolution simulation setup for the boundary conditions of a moderate climate is employed, and what is new is that both thermal and phase transition physics are considered. One of the main contributions of this work is to explore the PCM geometry optimization requirements. Simulation results demonstrate that optimized PCM geometries significantly accelerate thermal response, improve phase change uniformity, and enhance heat distribution across the wall