Two-phase fluids are considered as high-performance fluids for secondary refrigeration thanks to high energy density of phase change material (PCM). Nevertheless, one limitation in such system is thermal energy storage dynamic, in particular PCM charging/discharging rate, which depends generally on fluid temperature and flow rate. In the present work, the influence of pressure on the charging/discharging processes of gas hydrates has been studied experimentally using a stirred tank reactor. A model of stirred tank reactor was also developed and validated. The results showed that pressure can be used to adjust gas-hydrate phase-change temperature and consequently to improve charging/discharging time. For the same working conditions (temperature, flow rate, charging time…), the amount of stored energy using gas hydrates at 3 MPa is two times higher than that using water. The model was used to compare gas hydrates slurries to other slurries at ambient pressure.