A process for the production of hydrogen by means of thermal energy based on a solid energy carrier, characterized by comprising: - an oxidation segment (i) including step one of the process, in which, in a hydrogen-release reaction vessel, oxidation of a metal M, wherein a metal M is selected from a group consisting of elemental metals selected from Fe, Zn, Sn, Al or Mg, mutual alloys of these metals, preferably Zn-Fe alloys, intermetallic compounds of these metals, preferably Fe 3 Zn 10, FeZn 7, Fe 5 Sn 3, FeSn, and multi-element metals containing a major proportion of said elemental metals, is carried out with a hydrochloric acid solution at room temperature, resulting in the production of hydrogen gas and a metal-chloride salt solution; - a regeneration segment (ii), in which reduction of metal ions is carried out for the regeneration of a metal M, comprising step two which is crystallization in a crystallization unit, step three which is step one of heat treatment in a system for step one of heat treatment, and step five which is step two of heat treatment in the system for step two of heat treatment, and wherein the regeneration of the metal ions in the chloride solution, formed in the oxidation segment (i), is carried out by reducing the oxidation state of the metal ions by heat treatment, in which in step two which is crystallization, liquid water is evaporated causing the crystallization of the metal-chloride salt or the metal chloride hydrate, and then in step three, which is step one of heat treatment, a metal chloride salt or metal chloride hydrate is converted into metal oxide, metal oxohydroxide or metal hydroxide species in air, which are then in step five which is step two of heat treatment, in the reduction process, converted to elemental metal, wherein oxygen or reducing agent oxide is formed, and the obtained elemental metal is reintroduced to the oxidation segment (i) of the process; and - a segment (iii) of capturing gaseous HCl, in which in step four of the process, in the system for dissolving gaseous HCl in water, the gaseous HCl released in step one of heat treatment of metal chloride is dissolved in water, wherein an aqueous HCl solution is obtained which is led for re-use to the oxidation segment (i) of the process or stored in suitable tanks for re-use in the oxidation segment (i), wherein individual segments of the process can be repeated once or several times. - an oxidation segment (i) including step one of the process, in which, in a hydrogen-release reaction vessel, oxidation of a metal M, wherein a metal M is selected from a group consisting of elemental metals selected from Fe, Zn, Sn, Al or Mg, mutual alloys of these metals, preferably Zn-Fe alloys, intermetallic compounds of these metals, preferably Fe 3 Zn 10, FeZn 7, Fe 5 Sn 3, FeSn, and multi-element metals containing a major proportion of said elemental metals, is carried out with a hydrochloric acid solution at room temperature, resulting in the production of hydrogen gas and a metal-chloride salt solution; - a regeneration segment (ii), in which reduction of metal ions is carried out for the regeneration of a metal M, comprising step two which is crystallization in a crystallization unit, step three which is step one of heat treatment in a system for step one of heat treatment, and step five which is step two of heat treatment in the system for step two of heat treatment, and wherein the regeneration of the metal ions in the chloride solution, formed in the oxidation segment (i), is carried out by reducing the oxidation state of the metal ions by heat treatment, in which in step two which is crystallization, liquid water is evaporated causing the crystallization of the metal-chloride salt or the metal chloride hydrate, and then in step three, which is step one of heat treatment, a metal chloride salt or metal chloride hydrate is converted into metal oxide, metal oxohydroxide or metal hydroxide species in air, which are then in step five which is step two of heat treatment, in the reduction process, converted to elemental metal, wherein oxygen or reducing agent oxide is formed, and the obtained elemental metal is reintroduced to the oxidation segment (i) of the process; and and wherein the regeneration of the metal ions in the chloride solution, formed in the oxidation segment (i), is carried out by reducing the oxidation state of the metal ions by heat treatment, in which in step two which is crystallization, liquid water is evaporated causing the crystallization of the metal-chloride salt or the metal chloride hydrate, and then in step three, which is step one of heat treatment, a metal chloride salt or metal chloride hydrate is converted into metal oxide, metal oxohydroxide or metal hydroxide species in air, which are then in step five which is step two of heat treatment, in the reduction process, converted to elemental metal, wherein oxygen or reducing agent oxide is formed, and the obtained elemental metal is reintroduced to the oxidation segment (i) of the process; - a segment (iii) of capturing gaseous HCl, in which in step four of the process, in the system for dissolving gaseous HCl in water, the gaseous HCl released in step one of heat treatment of metal chloride is dissolved in water, wherein an aqueous HCl solution is obtained which is led for re-use to the oxidation segment (i) of the process or stored in suitable tanks for re-use in the oxidation segment (i),