Local cooling unit and cooling system

A cooling system for at least one electric device, comprising:

• a first rack row and a second rack row, in which a plurality of racks are arranged, wherein each of the plurality of racks is configured to house an electric device including a first fan, and each of the plurality of racks has both an air suction port formed in one side of the rack and an air exhaust port formed in another side of the rack opposite to the one side, and wherein the first rack row and the second rack row are disposed such that their respective air exhaust ports oppose each other, and a gap with a predetermined size is interposed therebetween;
• a plurality of local cooling units, each configured to cool a rack row, wherein at least one first local cooling unit and second cooling unit, serving as an opposing pair of local cooling units, of the plurality of local cooling units, are disposed above the first rack row and the second rack row, respectively, in an opposing manner, wherein the gap with the predetermined size is covered by a combination of the first local cooling unit disposed above the first rack row and the second local cooling unit disposed above the second rack row, and wherein each of the first local cooling unit and the second local cooling unit includes:
• a housing having a cavity formed in the housing;
• an air inlet port provided in a bottom surface of the housing and open to the predetermined gap, to take in exhaust heat air from the rack row, via the predetermined gap;
• an evaporator provided in the housing, and configured to evaporate a refrigerant by heat exchange with air sucked in from the air inlet port, to cool the air, the refrigerant passing through an inside of the evaporator;
• an air outlet port provided in a side surface of the housing, and configured to exhaust the air cooled by the evaporator to a rack row side having the air suction ports of the racks;
• and
• a second fan configured to move the air from the air inlet port to the air outlet port;
• wherein the first local cooling unit exhausts air cooled by the evaporator to the rack row side of the first rack row, having the air suction ports of the racks, and the second local cooling unit exhausts air cooled by the evaporator to the rack row side of the second rack row, having the air suction ports of the racks;
• a cooling tower and/or condenser, disposed above the plurality of local cooling units;
• a gas piping configured to transport a refrigerant, which has been evaporated in an evaporator, to the cooling tower and/or condenser;
• and
• a liquid piping configured to transport the refrigerant, which has been condensed in the cooling tower and/or condenser, to the evaporator;
• wherein the refrigerant is naturally circulated via gravity.