Method for operating cyclic-process-based systems with a hot-side reservoir and a cold-side reservoir and at least one fluid chamber (4, 5), with an evaporator region and a condenser region for a working fluid and at least one heat-exchanger unit with at least one calorically active material element (11, 12), wherein the calorically active material element (11, 12) is arranged in the fluid chamber (4, 5) so as to be indirectly or directly operatively connected to the working fluid and a heat transfer between the calorically active material of the calorically active material element (11, 12) and the working fluid takes place by means of a latent heat transfer, the method comprising the following steps: A activating an electric field and/or magnetic field and/or mechanical stress field such that the calorically active material is at least temporarily subjected to interaction with the aforementioned electric field and/or magnetic field and/or mechanical stress field; B evaporating the working fluid through heating of the calorically active material by a first temperature change, induced in method step A, of the calorically active material to above a base temperature, wherein the base temperature is a temperature of the calorically active material without field application; C discharging the working fluid to the hot-side reservoir and condensing the working fluid at the condenser region, wherein heat is transported by means of latent heat of the evaporated working fluid; D return transport of the condensed working fluid from the condenser region to the evaporator region; E deactivating the electric and/or magnetic and/or elastic field; F causing a second, opposite temperature change of the calorically active material to below the base temperature; G feeding of the working fluid from the cold-side reservoir into the fluid chamber, wherein heat is transported from the evaporator region into the fluid chamber by means of latent heat of the evaporated working fluid; characterized in that the base temperature of the calorically active material element is controlled or regulated by means of a cooling fluid. the method comprising the following steps: A activating an electric field and/or magnetic field and/or mechanical stress field such that the calorically active material is at least temporarily subjected to interaction with the aforementioned electric field and/or magnetic field and/or mechanical stress field; B evaporating the working fluid through heating of the calorically active material by a first temperature change, induced in method step A, of the calorically active material to above a base temperature, wherein the base temperature is a temperature of the calorically active material without field application; C discharging the working fluid to the hot-side reservoir and condensing the working fluid at the condenser region, wherein heat is transported by means of latent heat of the evaporated working fluid; D return transport of the condensed working fluid from the condenser region to the evaporator region; E deactivating the electric and/or magnetic and/or elastic field; F causing a second, opposite temperature change of the calorically active material to below the base temperature; G feeding of the working fluid from the cold-side reservoir into the fluid chamber, wherein heat is transported from the evaporator region into the fluid chamber by means of latent heat of the evaporated working fluid; A activating an electric field and/or magnetic field and/or mechanical stress field such that the calorically active material is at least temporarily subjected to interaction with the aforementioned electric field and/or magnetic field and/or mechanical stress field; B evaporating the working fluid through heating of the calorically active material by a first temperature change, induced in method step A, of the calorically active material to above a base temperature, wherein the base temperature is a temperature of the calorically active material without field application; C discharging the working fluid to the hot-side reservoir and condensing the working fluid at the condenser region, wherein heat is transported by means of latent heat of the evaporated working fluid; D return transport of the condensed working fluid from the condenser region to the evaporator region; E deactivating the electric and/or magnetic and/or elastic field; F causing a second, opposite temperature change of the calorically active material to below the base temperature; G feeding of the working fluid from the cold-side reservoir into the fluid chamber, wherein heat is transported from the evaporator region into the fluid chamber by means of latent heat of the evaporated working fluid; characterized in that the base temperature of the calorically active material element is controlled or regulated by means of a cooling fluid.