Optimization of the Thermal Mass of PCM-Based Envelopes for Office Buildings in a Sharply Continental Climate

This study investigates the multi-objective optimization of phase change materials (PCM) in building envelopes for office buildings under sharply continental climate conditions. The study employed simulation modeling with dynamic solutions in EnergyPlus (CondFD algorithm) and the NSGA-II genetic algorithm. During the computational experiments, the optimal values for the PCM melting temperature (24–25°C), layer thickness (15–21 mm), and its position relative to the inner wall surface (10–20 mm) were determined. The results show that a properly selected PCM can reduce annual energy consumption by up to 22% and hours of thermal discomfort by up to 42% compared to a traditional concrete wall. The obtained calculation data can be used by architects and engineers when designing energy-efficient office buildings in regions with a sharply continental climate. As such, these results provide design-oriented practical guidance for integrating PCM into building envelope design to support eidence-based decision-making at early stages of any projects.