Feasibility of trichlorofluoromethane (CCl3F,R11) heptadecahydrate as a heat storage material

Trichlorofluoromethane (CCl₃F, R11) heptadecahydrate, which melts at 8.5°C with a heat of fusion of 274 kJ/kg (65.4 cal/g), was investigated as a latent heat storage material. Addition of nonionic surfactant, 2 wt% to water in R11 hydrate, increased the formation rate of the hydrate about 4 times which is sufficient for practical use. Phase separation of R11 was prevented effectively in a gel matrix formed by polyacrylamide (PAA) or gelatin. The PAA gel containing the hydrate-surfactant had an apparent latent heat of fusion of 167–209 kJ/kg (40–50 cal/g), repeating phase change successfully over 100 cycles without deterioration in a heat cycle test (0–20°C, 5 cycles/day). Tetrabutyl ammonium fluoride hydrate (C₄H₉)₄NF 34.4 H₂O] was found effective as a nucleating agent.