Cold storage by tetra-n-butyl ammonium bromide clathrate hydrate slurry generated with different storage approaches at 40 wt% initial aqueous solution concentration

• TBAB CHS generation at 40 wt% initial aqueous solution concentration was investigated.
• Homogeneous and heterogeneous storage approaches were used for TBAB CHS generation.
• Influence of filter screen inside of heterogeneous storage tank was studied.
• Heterogeneous storage approach led to less crystal adhesion on heat transfer surface.

In the present study, the performance of cold storage by tetra-n-butyl ammonium bromide (TBAB) clathrate hydrate slurry (CHS) was studied. TBAB CHS was generated at 40 wt% initial aqueous solution concentration and the experiments were conducted with two different storage approaches, i.e., homogeneous storage and heterogeneous storage, in which the mass fraction of TBAB CHS was experimentally determined by melting experiments. It was found that the mass fraction of TBAB CHS and system COP of heterogeneous storage approach were much higher than those of homogeneous storage approach due to less crystal adhesion on the heat exchanger wall. Moreover, a filter screen was employed in the heterogeneous storage tank to impede the ascending of TBAB hydrate crystals to the top of storage tank. The results showed that the filter screen could reduce TBAB hydrate crystals being pumped into the heat exchanger, resulting in less crystal adhesion on the heat exchanger wall.