Modelagem semianalítica de Trocadores de Calor Solo-Ar com material de mudança fase

Abstract

This work presents a semi-analytical approach to evaluate the thermal performance of Earth-to-Air Heat Exchangers (EAHEs) integrated with Phase Change Materials (PCM), focusing on applications in passive building climatization. The modeling combines a one-dimensional (1D) analytical formulation for the air duct with two-dimensional (2D) transient numerical simulations of the soil using ANSYS Fluent, considering the presence of the PCM surrounding the duct. The BioPCM Q20 was used as the phase change material, applied in a 5 cm annular layer around the buried duct. Four different duct lengths were investigated to assess their influence on the thermal performance of the system. The main performance indicator was the Thermal Potential (TP), defined as the difference between inlet and outlet air temperatures. Case studies were conducted for the cities of Pelotas–RS and Viamão–RS, based on real temperature data for soil and air. The results were validated against data from the literature, presenting a Mean Absolute Percentage Error (MAPE) ranging from 0.930% to 3.451%, which confirms the robustness of the proposed model. Viamão exhibited better performance in cooling mode, with an annual average TP of up to 3.62 C and improvements of up to 38.15% during summer. Conversely, Pelotas was more efficient in heating mode, reaching an annual average TP of 4.87 C and improvements of up to 23.98% in the colder months. The results demonstrate the technical feasibility of the TCSA-PCM system as a sustainable solution for passive climatization, highlighting the importance of adapting to local climatic conditions in system design. The adopted methodology proved to be accurate and replicable, and it can be extended to different geographic and operational contexts.