CO2 hydrate slurry is a promising phase change material for cold storage and distribution issues, due to its high latent heat (about 500 kJ.kg-1 of water, higher than that of ice - 333 kJ.kg-1) and wide melting temperature range suitable for air conditioning application. While the thermodynamic properties of CO2 hydrates are now well established, knowledge of crystallization kinetics phenomena is still a challenge. Trying to understand and control the formation of gas hydrates is a key factor, since their discovery in pipeline plugs. The goal here, for cooling application, is to increase the rate of CO2 hydrate formation. Most laboratory-scale hydrate reactors are equipped with pressure and temperature probes, and mass balance on CO2 allows formation kinetic studies, but with assumptions on CO2 concentration in the liquid phase and the hydration number. The present work investigates the kinetics of CO2 hydrate crystallization for two different types of stirrers, on one hand a three pitched blade stirrer and on the other hand a hollow shaft eight blade Rushton turbine. We use a jacketed stirred batch reactor, with a specially developed sensor (a thermopile) to determine experimentally heat balance on the cooling jacket. The mass fraction of crystallized hydrate during the time is determined directly from this heat balance. Those results are compared with mass balance approach. To highlight the effect of stirrer type on mass transfer, especially between vapour and liquid phases, an additional experimental study to determine vapour/liquid mass transfer coefficient, kLa, were achieved. We conclude about the global performance for heat and mass transfers of both stirrer, and give general recommendation for the choice of stirrer type and scale-up process.