Advanced numerical modeling of the thermal and energy performance of a floor heating system incorporating phase change material

In this article, a novel 2D numerical model based on the finite element method (FEM) was created to simulate the thermal behavior of floor heating integrating macro-encapsulated PCM, using the effective thermal capacity approach. Our numerical model was validated by comparing its results with those reported in the literature. In this work, a thorough analysis of various organic and inorganic PCMs was carried out to identify the most suitable material. This analysis focused on evaluating several key factors influencing the thermal behavior of the heating system, including variations in the hot water supply temperature, the thickness of the PCM layer, and the determination of its optimal placement within the coating layer. The numerical simulation results indicate that zinc nitrate hexahydrate exhibits better thermal performance compared to other proposed types of PCM. Besides, using a PCM layer thickness of 15 mm and positioning it under the tile in location y5, with a hot water supply temperature of 50 °C, provides improved thermal storage capacity. This configuration can stabilize the floor temperature in the bathroom at 34.10 °C, even 3 h and 30 min after the heating system has been turned off, resulting in a temperature difference of 11.40 °C compared to the reference case without PCM. The economic and environmental analysis demonstrates that incorporating PCM into the heating system offers a return on investment of approximately 9.96 years. Furthermore, it achieves a daily reduction in CO2 emissions of around 38.19 % compared to a heating system without PCM.