Tailored calcium chloride hexahydrate as a composite phase change material for cold storage

In this study, a water-salt system composite phase change material with calcium chloride hexahydrate (CCH, CaCl 2 ·6H 2 O) as the main cold storage functional body was successfully tailored. The phase change temperature of CaCl 2 ·6H 2 O was reduced by adding urea and ammonium chloride (NH 4 Cl), and its supercooling and phase separation were suppressed by adding strontium chloride hexahydrate (SrCl 2 ·6H 2 O) and sodium carboxymethyl cellulose (CMC). The preferred composite phase change material (CCH-UNSC4) consisted of 76 wt% CaCl 2 ·6H 2 O, 11 wt% urea, 6 wt% NH 4 Cl, 4 wt% SrCl 2 ·6H 2 O, and 3 wt% CMC, which had a melting phase change temperature of 9.51 °C, a latent heat of melting of 99.08 J g −1 , and a supercooling degree of only 0.39 °C. The thermal conductivity of CCH-UNSC4 reached 0.330 W m −1 K −1 . Its phase change properties were basically unchanged after 50 thermal cycles, showing good cycling stability. Cold storage and release experiments and fruit storage experiments showed that CCH-UNSC4 can play its advantages in cold chain transportation. • Calcium chloride hexahydrate was tailored as a phase change cold storage material. • The modulation mechanism of the phase change behavior of calcium chloride hexahydrate was elaborated. • Tailored calcium chloride hexahydrate has very promising application prospects in cold chain transportation.