TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: A part of the quantity of heat released during the formation of the metal hydride is utilized for heating the part of the metal hydride. A part of the quantity of heat released by combusting the charge and the quantity of heat conveyed by the hot produced hydrogen is utilized for heating the metal hydride. The part of the utilized heat for heating the metal hydride is circulated after being stored in a coolant material. The method is performed continuously or discontinuously. Preferred Components: The solid pyrotechnic charge is a pyrotechnic charge containing a pyrotechnic product containing 96 mass% of an inorganic oxidizing component and a hydrogenated reducing component consisting of inorganic hydrides, borazane and polyaminoboranes. The hydrogenated reducing component includes inorganic hydrides consisting of inorganic borohydrides, preferably alkali and alkaline earth metal borohydrides (comprising sodium borohydride, lithium borohydride and magnesium borohydride), and consists of borazane (preferred) and polyaminoboranes. The inorganic oxidizing component includes perchlorates, dinitro amides, nitrates and metal oxides, preferably ammonium perchlorate, ammonium dinitroamide, strontium nitrate and iron oxide. The pyrotechnic product contains: 40-80 mass%, preferably more than 70 mass% of hydrogenated reducing component and 20-60 mass%, preferably 25-45 mass% of inorganic oxidizing component. A metal compounds and/or intermediate compounds are utilized for storing the hydrogen in the form of metal hydride.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The combustion chamber and a first part of the tube, starting at the level of the delivering orifice of the chamber, are arranged in an enclosure, preferably insulated enclosure adapted to contain a heat transfer material. The tank is arranged in another enclosure. The device further comprises a unit for circulating the heat transfer material towards another enclosure. The combustion chamber, tube and the tank are arranged in the enclosure. The tank has geometry with fins suitable for enclosing at least one of the compounds adapted for storing hydrogen.