Research on cool storage and release characteristics of R134a gas hydrate with additive

Theoretically R134a gas hydrate is a good choice for practical cool storage application due to its excellent boiling and condensation properties, but earlier researches indicate that pure R134a alone is not suitable for practical cool storage application as it floats and occupies upper space in the storage tank, resulting in difficulty both in the storage and release processes. For this reason, this study tries to develop R134a hydrate's potential in cool storage by means of alcohol additives. The system has been performed to test the performance of both cool storage and release process and its industrial applicability. The results show that 1.34% n-butanol additive among three different concentrations exhibits the best result which substantially accelerates the cool storage rate. The lumped hydrate density increases apparently comparing with pure R134a hydrate running, which eliminates the hydrate floating during the hydration process under certain additive concentration. It indicates that the added alcohol in R134a hydrate-water solution is essential for a stable and smooth cool storage operation and a cool storage tank with indirect-contact configuration is industrially applicable.

► Addition of certain alcohol in R134a hydrate-water solution is essential for a stable and smooth cool storage operation. ► Addition of n-butanol causes large difference in pressure variation in cool storage process. ► Addition of n-butanol to water solution increases the R134a hydrate's density.