Thermodynamic modelling of formation/dissociation cycles of two-phase slurries in secondary refrigeration system
Résumé
The thermodynamic modelling of the formation/dissociation cycles of two-phase refrigerants such as ice and hydrate slurries is developed. Ice slurries are already used for industrial applications but their generation requires mechanical processes (scraping or brushing surface exchangers) which increase exergy losses. Hydrates are ice-like crystalline structures composed of water molecules linked together by hydrogen bonds, forming cages in which are trapped guest molecules (CH4, CO2, salt
). Hydrate slurries composed of a suspension of hydrate crystals in aqueous solution can also be used as secondary refrigerants and have the advantage of being able to form without mechanical processes. The originality of this study is to characterize the heat and the gas transfer (in hydrate case) in these systems and to evaluate the impact of these transfers on cold storage and distribution efficiency. A higher performance is obtained by hydrate slurries because of their higher temperature level and energy density.