With initial water at 26℃ and 15℃ and charge pressure at 3.6-4.2 MPa in the reaction kettle

the hydrates growth and cool storage characteristics of CO2 hydrates produced in direct-contact way were studied. When initial water was at 15℃ and charge pressure was at 3.6 MPa

precooling time was short

about 11min

and sub-cooled temperature was about 1.3℃ but temperature increment was not obvious at the beginning of growth

and total cool storage average rate and efficiency were about 82.4 kJ·min-1 and 4.34 respectively. At other temperatures and pressures

there were longer precooling time (between 20-55 min

but decreasing with the increase of charge pressure)

higher sub-cooled temperature (at 5.5-9.7℃)

rapid growth rate and dense hydrates. Temperature increment was obvious and the largest was at 4.0 MPa; hydrates average growth rate

total storage amount

total cool storage average rate and efficiency increased with the increase of charge pressure

and their maximum values at the experimental initial water temperatures were 77 and 154 g·min-1

3.725 and 3.791 MJ

64.1 and 99.5 kJ·min-1

3.14 and 4.91 respectively. The hydrates decomposition releasing cool was a phase change process

and phase transition temperature was generally 10-14℃.