Abstract: A thermal energy storage system includes: a thermal energy storage having an upper space for storing hot water and having a lower space for storing cold water, in which the hot water and the cold water are stratified; an upper diffuser located in the upper space; and a lower diffuser located in the lower space, wherein the thermal energy storage includes: a body having a cylindrical shape and having a central axis arranged parallel to a ground; a first dome part having a dome shape and configured to seal open one side of the body; a second dome part having a dome shape and configured to seal an open opposite side of the body; and a plurality of separation plates spaced apart from each other in a vertical direction within the body.

Abstract: A diffuser and a heat storage tank system including the same includes: a heat storage tank formed therein with an internal space in which hot water and cold water are stratified; an upper diffuser positioned in an upper space of the heat storage tank to supply water; and a lower diffuser positioned in a lower space of the heat storage tank to supply water, wherein each of the upper diffuser and the lower diffuser includes: a first nozzle formed on one side thereof with a first discharge port for discharging the water; and a second nozzle disposed at a predetermined distance from the first nozzle and having a second discharge port formed on one side thereof opposite to the one side of the first nozzle formed with the first discharge port.

Abstract: A thermal energy storage system includes: a thermal energy storage having an upper space for storing hot water and having a lower space for storing cold water, in which the hot water and the cold water are stratified; an upper diffuser located in the upper space; and a lower diffuser located in the lower space, wherein the thermal energy storage includes: a body having a cylindrical shape and having a central axis arranged parallel to a ground; a first dome part having a dome shape and configured to seal open one side of the body; a second dome part having a dome shape and configured to seal an open opposite side of the body; and a plurality of separation plates spaced apart from each other in a vertical direction within the body.