Microencapsulated phase change materials: Facile preparation and application in building energy conservation

•Microencapsulated phase change materials (PCM@CMC-CS) using for the building envelopes were designed and prepared in a simple way.•CMC-CS shell was formed through electrostatic interaction between the carboxyl group in the CMC molecule and the amino group in the CS molecule.•Morphology, chemical structure and thermal properties of PCM@CMC-CS were described and analyzed.•The PCM@CMC-CS hydrogel particles as template were added to prepare low density porous gypsum-matrix models.•The models with PCM@CMC-CS had an improved capacity of thermal inertia as well as lower inner temperatures.