It is about ocean provided cold tap water as the cooling media for architectural air conditioning system. It comprises ocean water filter, water drawing pipeline, water flow sensor, stop valve, multiple-stage centrifugal pump, three way valve, rapid filter, precipitation filter, secondary filter, underground ocean water reservoir, sea water pump, plate heat exchanger, water transmitting pump, underground cold water reservoir, water service pump, air cooling processor, purified water tank, butterfly valve and return pipe. The cold ocean water after treatment through the rapid filter, precipitation filter, and secondary filter exchanges heat with tap water inside the plate heat exchanger, using the original municipal underground pipeline network to transmit tap water, playing both roles of water transmission and cooling. It makes full use of the coldness of the subsurface water, saving a lot of electric power, free from the damage of Freon to the atmospheric ozone layer and it is beneficial to environment protection. It has significant economic and social effects.