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.