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Enhancing energy efficiency in the building sector is vital for climate change mitigation. Phase change materials (PCM), known for their high latent heat storage capacity during phase transitions, offer promising potential in regulating indoor temperatures and reducing dependence on HVAC systems. This study presents a preliminary experimental investigation into the thermal performance of wallboards enhanced with PCM under subarctic conditions in Umeå, Sweden. Four types of wallboards were tested: a conventional gypsum board, a commercial PCM board (cPCM), and two lab-fabricated boards with 60% and 82% microencapsulated PCM by mass (mPCM60 and mPCM82). Thermal properties of the PCM were characterized using Differential Scanning Calorimetry (DSC), confirming high latent heat capacity and thermal stability. In a field setup, surface temperatures were monitored to assess thermal buffering capacity. Results show lower temperature fluctuations in the mPCM82 and mPCM60 wallboards, indicating enhanced thermal performance of the envelope compared to the gypsum board. However, the thermal performance of cPCM was even worse than gypsum, which could be attributed to the observed material settlement. These findings suggest the potential of PCM-enhanced wallboards to improve indoor thermal comfort and energy performance, while also emphasizing the importance of material selection and design in practical applications.

Polyurethane (PU) as a popular polymer is widely recognized for its exceptional thermal insulation properties, making it a critical material for applications requiring effective heat transfer management. Integrating Phase Change Materials (PCMs) into PU (PU-PCMs) has emerged as a highly effective strategy for enhancing building envelope performance, ensuring greater indoor thermal stability, and mitigating temperature fluctuations. This study introduces an Enhanced Multi-Scale Modeling approach to investigate the thermal conductivity and energy efficiency of PU-PCMs, with a particular focus on their comparative performance in subarctic and tropical climates. By combining Molecular Dynamics (MD) simulations with Finite Element Methods (FEM), the model seamlessly bridges molecular-scale interactions with macroscopic thermal behavior. Using a Representative Volume Element (RVE)-FEM framework, microscopic properties are translated into engineering-scale parameters, enabling accurate and efficient predictions of material performance across diverse climatic conditions. The findings demonstrate the capability of PU-PCMs to significantly enhance energy efficiency and indoor thermal comfort. In a case study of a single-family house, PU-PCMs achieved a 7.376% reduction in energy consumption and increased comfort hours under Stockholm's subarctic climate. Moreover, the adaptability of PU-PCMs was validated in both tropical and subarctic environments, consistently stabilizing indoor temperatures, reducing HVAC energy demands, and improving occupant comfort. These results underscore the potential of PU-PCMs as a passive thermal management solution, advancing sustainable building practices. The proposed multi-scale model offers a computationally efficient and precise tool for optimizing material design in energy-sensitive applications, reinforcing the versatility and significance of PU-PCMs across a range of climatic conditions.

This study offers a comprehensive review of the state-of-the-art developments regarding the application of phase change materials (PCMs) into building envelopes and HVAC systems. Incorporating PCMs into building envelopes can significantly enhance thermal storage capacity and reduce the influence of outdoor temperature fluctuations on interior spaces' thermal conditions. Furthermore, combining PCM-enhanced building envelopes with night ventilation can effectively utilize natural cooling resources, thereby improving both the adaptability and efficiency of PCMs in regulating indoor thermal environments and reducing building energy consumption. An alternative approach for energy conservation involves integrating PCMs directly within ventilation and air conditioning systems. This review offers insights and recommendations for future research, highlighting the necessity of further developments in materials science, system optimization, and real-world application studies to maximize the potential of PCMs in the built environment.