The present invention relates to a sterilising device (1), comprising at least one chamber (2) for sterilising products (4), a primary fluid circuit (3) connected to the chamber (2) for providing hot water and/or hot steam to the chamber, a secondary fluid circuit (8) for heating and/or cooling the primary fluid circuit (3), wherein the secondary fluid circuit (8) is connected to the primary fluid circuit (3) by means of a second heat exchanger (5), and a stratified storage tank (11) in the secondary fluid circuit (8) having a plurality of temperature zones (12), wherein the temperature zones (12) can be separately charged with and discharged of the fluid of the secondary fluid circuit (8).
