The cold thermal energy storage characteristics of CO2 hydrates were studied in different mass concentrations of SDS surfactant (0.4

0.5

and 0.6 g/L)

SDBS surfactant (0.2

0.3

and 0.4 g/L)

and compound surfactants (SDS+SDBS) using a vapor compression refrigeration system. Compared with a pure-water system

SDS

SDBS

and compound (SDS+SDBS) surfactants improve the CO2 hydrate cold thermal energy storage performance

and the best concentrations of the surfactants were 0.5 g/L

0.3 g/L

and 0.5 g/L(SDS)+0.3 g/L(SDBS)

respectively. Comparing the cold thermal energy storage performance of SDS

SDBS

and compound (SDS+SDBS) surfactants

the compound surfactant 0.5 g/L(SDS)+0.3 g/L(SDBS) had the best cold thermal energy storage performance: the precooling time (21.51 min) and cold thermal energy storage time (27.56 min) were the shortest. The latent heat storage capacity (1 308.27 kJ)

total storage capacity (2 967.35 kJ)

average charging rate (1.79 kW)

and hydrate formation mass (2.55 kg) were the largest. The findings indicate that the compound surfactant had the most significant effect on the CO2 hydrate cold thermal energy storage characteristics of this system.