High density storage of ammonia

A system for delivery of ammonia to an ammonia consuming unit wherein the system comprises a discharge chamber having a single opening, said opening being used for delivery of ammonia, said chamber comprising a compacted ammonia absorbing/desorbing solid material in the form of one or more compacted units, means for heating said chamber wherein ammonia is released by thermal desorption, and means for conveying the desorbed ammonia from said discharge chamber to one or more ammonia consuming units, wherein said compacted ammonia absorbing/desorbing solid material is selected from an ionic salt of the general formula Ma(NH3)nXz wherein M is one or more cations selected from alkali metals, alkaline earth metals, aluminum, transition metals and combinations thereof, X is one or more anions selected from fluoride, chloride, bromide, iodide, nitrate, thiocyanate, sulphate, molybdate and phosphate ions, a is the number of cations per salt molecule, z is the number of anions per salt molecule, and n is the coordination number of 2 to 12, said ionic salt being compacted to a density above 50% of the theoretical skeleton density, and wherein the volume of a compacted unit of said compacted ammonia absorbing/desorbing solid material ranges from about 1 cm3 to about 1000 liters.