“…However, the problem with PCMs is the loss of their shape due to the transition of the phase-change agent to a molten low-viscous state, which is not permissible in all applications [ 23 , 24 , 25 ]. The solution to this problem is to cover the phase-change agent with a shell [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ] or place it into a continuous solid matrix [ 33 , 34 , 35 , 36 , 37 ].…”