Absorption thermal storage

as a kind of thermal storage technology with high energy storage density and long thermal storage period

is the key to storing solar thermal energy and solving the mismatching between solar thermal energy supplying and demanding during different seasons. Traditional absorption systems avoid crystallization by limiting the solution concentration

which assures reliability and safety but causes a limited energy storage density to the system. In this paper

a closed three-phase absorption heat storage system is designed and tested. Through filtering and high level inlet by the filters

crystal fusion by the heating rods

and flushing of the solution circulation lines

the system can operate normally after the solution crystallization

increase the concentration glide

and improve the energy storage density. After tested

the energy storage density of the system can reach 220 kWh/m3 when supplying heat

which is a 114% increase compared with traditional two-phase absorption heat storage systems. Hence three-phase absorption heat storage technology with the utilization of crystallization is expected to realize high-density long-term solar energy thermal storage.