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

Abstract

In this study, a water-salt system composite phase change material with calcium chloride hexahydrate (CCH, CaCl2·6H2O) as the main cold storage functional body was successfully tailored. The phase change temperature of CaCl2·6H2O was reduced by adding urea and ammonium chloride (NH4Cl), and its supercooling and phase separation were suppressed by adding strontium chloride hexahydrate (SrCl2·6H2O) and sodium carboxymethyl cellulose (CMC). The preferred composite phase change material (CCH-UNSC4) consisted of 76 wt% CaCl2·6H2O, 11 wt% urea, 6 wt% NH4Cl, 4 wt% SrCl2·6H2O, 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.