An evaporative air conditioner system includes a heat exchanger having an inlet and an outlet and a plurality of passageways between the inlet and the outlet; a pump and nozzle assembly for introducing pressurized air and water to the inlet of the heat exchanger to create a mist of water droplets suspended in air; a vacuum assembly for creating a partial vacuum near the outlet of the heat exchanger to draw the mist through the passageways and to the outlet of the heat exchanger to remove heat from the heat exchanger through evaporative cooling; and a transfer mechanism for moving a medium past the heat exchanger to remove heat from the air without permitting the medium to mix with the mist drawn through the heat exchanger.