Modelling of the available latent heat of a CO2 hydrate slurry in an experimental loop applied to secondary refrigeration

The present study investigates the suitability of CO2 hydrate for a use as phase change material in two-phase secondary refrigeration. Unlike the generation of the classical two-phase refrigerants, power limited by mechanical parts, hydrate slurry production has the advantage of being performed using a nonmechanical process. Nevertheless, in order to be efficient, the hydrate slurry needs to fulfil two major conditions: a high latent heat of melting of the solid phase and appropriate flowing conditions of the slurry carrying a sufficient amount of solid. Consequently, in the present work, multi-cycle differential scanning calorimetry (DSC) measurements were performed and confirmed a value of CO2 hydrate dissociation enthalpy of approximately 500 kJ kg(w)(-1), one and a half higher than that of ice (333 kJ kg(w)(-1)). Moreover, an experimental loop made it possible to study the CO2 hydrates in suspension in a carrying liquid and to model the available enthalpy of the system related to the solid fraction of the slurry. (c) 2005 Elsevier B.V. All rights reserved.