Secondary refrigeration is a promising alternative to reduce the emission of primary refrigerants. CO2 hydrate slurry used as secondary refrigerant possesses the advantages of high latent heat of dissociation and nonmechanical generation. As the phase-change pressure of CO2 hydrate above 273.15 K is higher than what is fit for the classical installations, the tetra-n-butylammonium bromide (TBAB) was added into the system to decrease the phasechange pressure in the present work. Differential Thermal Analysis (Figure 1) and DSC devices were used for determining the formation conditions and dissociation enthalpies of hydrates in the TBAB +CO2 +H2O system.