“…[ 3 , 4 ]. Since the very beginning of the application of PCMs in various branches of engineering, prediction of their durability at aging has been the focus of attention for numerous researchers, and still remains an important problem [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Factors in external environments causing the aging of PCMs are the temperature and humidity of air, precipitation, oxygen, ozone, presence of chemically active compounds, and the ultraviolet (UV) radiation of the sun [ 5 , 6 , 7 , 8 , 14 , 15 ].…”