AbstractIn this work, microencapsulated phase change material (MEPCM) with the eutectic mixture of stearic acid (SA) and coconut oil (CO) as the core and melamine formaldehyde (MF) as the shell was developed by emulsion-polymerization method to be applied in the gypsum plaster tile as a passive way for thermal energy storage (TES) applications. Thermal and chemical characterization, particle size distribution (PSD), and thermal resistance of the developed MEPCM were investigated. The effects of adding MEPCM on thermal conductivity, density, and mechanical strength of gypsum plaster tile were reported. The results indicated an optimum eutectic combination ratio of 20%–80% by weight of SA-CO, MF concentrations of 75% by weight with 73.5% encapsulation efficiency for the synthesized MEPCM, phase change temperature of 21°C to 28.6°C and TES of 35.04 J/g. The reliability and thermal stability of the produced MEPCM was proved and implied no degradation in the chemical structure of MEPCM after repeated melting and solidification processes due to protection of core materials by MF shell. The gypsum/MEPCM composite resulted acceptable mechanical strength with thermal conductivity of 0.33 W/(m · K) and density of 919 kg/m3. The calculated extent of thermal energy storage for the simulated room that covered with G/M33 with 10% by weight of MEPCM in the interior walls and roof showed about 12% reduction in energy consumption.