In the context of the use of hydrates as environment-friendly alternative in two-phase secondary refrigeration, the present study investigates CO2 hydrate-ice mixtures using an experimental Differential Thermal Analysis (DTA) device. CO2 hydrate crystals are phase change materials which can be formed in temperature range corresponding to the operating conditions of secondary refrigeration and air-conditioning systems. Cooling/heating cycles were performed on CO2-water mixtures and a comparison with the DTA results obtained for ice crystallization allowed to estimate a dissociation enthalpy of approximately 500 kJ.kgw -1 that is one and half higher than that of ice. From experimental and literature data, and improved Clausius-Clapeyron equation, ice proportion in CO2 hydrate-ice mixtures were determined for various pressure and temperature conditions.