A corona discharge ozonator (10) is provided that comprises a first electrode (12), a second electrode (14) and a dielectric material (16) disposed between the electrodes. An ozonization chamber (24) is formed between one (14) of the electrodes and the dielectric material (16) and defines a fluidi flow path. A plurality of thermally-conducting solids (40) are within the fluid flow path. Substantially each of the solids touches another of the solids and either the dielectric material (16) or the first or second electrode (12, 14). These solids (40) transfer heat from the hotter (12) to the cooler (14) of the dielectric (16) and the first or second electrode when one (14) of the electrodes is cooled by a conventional means such as a water bath (34). Corona discharge ozonators (10) of the invention have improved ozone output and increased ozone production energy efficiency.