ENHANCING ENERGY EFFICIENCY OF THE PCM-INTEGRATED BUILDING ENVELOPE WITH DIVERSE VENTILATION STRATEGIES IN DIFFERENT REGIONS OF KAZAKHSTAN

Abstract

The growing global energy challenges, rapid urbanization, and climate change concerns necessitate innovative strategies to reduce building energy consumption. Phase Change Materials (PCMs), which capture and release substantial latent heat during phase transitions, stand out as an effective solution for reducing cooling energy demand and maintaining indoor thermal comfort. This research investigates the potential for enhancing energy efficiency in mid-rise residential buildings across Kazakhstan’s diverse climate zones through the integration of PCMs and natural ventilation strategies. Using energy simulations in DesignBuilder and EnergyPlus, the study evaluates thermal performance in fifteen cities representing three major climate zones. Four scenarios were examined: a reference case, PCM-only integration, PCM with natural night ventilation (NNV), and PCM with controlled natural ventilation (CNV). A key focus of the study is the interaction between building insulation—measured by R-value—and the performance of PCMs under different ventilation strategies. Two main performance indicators were used: cooling energy savings (CES) and latent heat energy storage efficiency (EC), which help quantify PCM effectiveness under varying insulation and ventilation conditions. The results demonstrate that local climate conditions significantly influence PCM performance, with RT26-HC performing optimally in cooler regions (Zones 1 and 3), while RT28-HC is more suitable for hotter climates (Zone 4). Furthermore, the study reveals that although higher insulation levels reduce external heat gains, they can inadvertently trap internal heat, leading to increased energy consumption and reduced PCM efficiency by restricting latent heat discharge—particularly in the absence of adequate ventilation. The PCM+CNV configuration proved to be the most effective in hot climates, achieving up to tenfold cooling energy savings compared to the reference case. Overall, this research provides practical, climate-specific guidelines for integrating PCM technologies into building envelopes. It underscores that a balanced combination of insulation properties, appropriate PCM selection, and effective ventilation can lead to significant energy savings and improved indoor comfort. These insights can support the development of sustainable, energy-efficient buildings in Kazakhstan and similar continental climates.