An air cooled condenser apparatus has a tubular shell having an open upper end and an open lower end, a ring of tube bundle panels disposed generally vertically and at an angle to each other, with each of the tube bundles comprising a primary condenser region and a secondary condenser region, and adapted for air flow therethrough to condense fluid in the panels, and configured so that air flow through the panels passes through and exits the open upper end of the shell, and a duct disposed at the ground level of the shell, and a non-condensable extraction system with active or passive devices to control the local rate of the evacuated mixture of non-condensables and attached steam.