Techno-economic evaluation of an elastic composite phase change material for building envelopes

This work developed an elastic form-stable composite phase change material (PCM) using RT 28 as organic PCMs and styrene-ethylene-butylene-styrene copolymer (SEBS) as the supporting matrix for building energy efficiency applications. Comprehensive characterization via SEM and FT-IR confirmed a physical combination between RT 28 and SEBS without chemical reaction or new compound formation. The DSC test results indicated that the phase change temperature and latent heat of composite PCMs were 25.1°C and 178.2 J/g, respectively. The TGA analysis demonstrated that the thermal stability of composite PCMs was improved compared to pure RT 28. After 200 thermal cycles, composite PCMs retained stable phase change properties. The thermal performance of composite PCMs incorporated into building envelopes was systematically evaluated through numerical simulations across five distinct climate regions. The results showed that PCM panels integrated into building envelopes reduced indoor temperature fluctuations in non-air-conditioned buildings and lowered HVAC energy consumption in air-conditioned buildings. It is worth mentioning that excessive PCM panel thickness increased energy consumption in mild climates (such as Kunming). The economic analysis revealed payback periods ranging from 18.0 years (Harbin) to 599.8 years (Kunming), confirming economic feasibility in severe cold regions. Overall, composite PCM offered significant potential for passive thermal regulation and energy savings in buildings.