Apparatus for energy and substance conversion by means of pyroelectric materials for producing dissociation products from fluids, comprising - at least not less than two pyroelectric transducers (20, 22) which are connected to one another in respect of a controlled valve device and each have an outflow conduit (11, 23), where a first pyroelectric transducer is suitable for dissociation of water into the dissociation products hydrogen and oxygen and a second pyroelectric transducer is suitable for dissociation of carbon dioxide into the dissociation products carbon monoxide and oxygen, - at least one conduit for discharge of dissociation products (48, 52) assigned to the first pyroelectric transducer, - at least one conduit for discharge of dissociating products (52, 48) assigned to the second pyroelectric transducer, where a pyroelectric transducer (20, 22) contains at least - a first heat exchanger which is connected to a feed conduit and has at least one outflow conduit connected to the feed conduit and through which a heat-accepting fluid containing water or carbon dioxide to be dissociated flows, - at least one reactor for dissociation of the fluid containing water or carbon dioxide into its dissociation products (48, 52), where the reactor comprises at least one pyroelectric material having a prescribed Curie temperature T c, - at least one second heat exchanger in the pyroelectric transducer (20, 22), which heat exchanger is connected to an external buffer medium unit for setting an average temperature, - an apparatus for gas phase transfer and/or gas separation from which at least the conduit for discharging at least one dissociation product (48, 52) produced in the reactor leads, where the apparatus comprises at least one separating unit assigned to the pyroelectric transducers (20, 22) for separating the final dissociation products (48, 52) discharged from the apparatus for gas phase transfer and/or gas separation located downstream of the respective reactor and the conduits (14, 24) open, for controlled discharge of the dissociation products (48, 52), into the separation unit from which at least conduits (25, 26) for discharge of separated final dissociation products (48, 52) lead, characterized in that the valve device is provided for an alternate introduction, with a prescribed valve control frequency, of at least one fluid stream having a high temperature T H and at least one fluid stream having a temperature T K which is lower than the temperature T H, and there is a controlled circulation pump which is arranged within a circuit which is present in the pyroelectric transducers (20, 22) and comprises the heat exchanger, reactor and apparatus for gas phase transfer and/or gas separation which belong to the circuit and are connected to one another and supplies the circuit with flowing fluid containing water or carbon dioxide to be dissociated via a conduit system connecting the circuit, where the circulation pump is connected externally via a control unit to the controlled valve device. - at least not less than two pyroelectric transducers (20, 22) which are connected to one another in respect of a controlled valve device and each have an outflow conduit (11, 23), where a first pyroelectric transducer is suitable for dissociation of water into the dissociation products hydrogen and oxygen and a second pyroelectric transducer is suitable for dissociation of carbon dioxide into the dissociation products carbon monoxide and oxygen, - at least one conduit for discharge of dissociation products (48, 52) assigned to the first pyroelectric transducer, - at least one conduit for discharge of dissociating products (52, 48) assigned to the second pyroelectric transducer, - a first heat exchanger which is connected to a feed conduit and has at least one outflow conduit connected to the feed conduit and through which a heat-accepting fluid containing water or carbon dioxide to be dissociated flows, - at least one reactor for dissociation of the fluid containing water or carbon dioxide into its dissociation products (48, 52), where the reactor comprises at least one pyroelectric material having a prescribed Curie temperature T c, - at least one second heat exchanger in the pyroelectric transducer (20, 22), which heat exchanger is connected to an external buffer medium unit for setting an average temperature, - an apparatus for gas phase transfer and/or gas separation from which at least the conduit for discharging at least one dissociation product (48, 52) produced in the reactor leads,