Abstract: Process for the reversible thermochemical storage of energy and release of energy, wherein, for the storage of energy, orthoboric acid is converted into boric oxide, metaboric acid or boric oxide and metaboric acid by loss of water, wherein, for the release of energy, boric oxide or metaboric acid or boric oxide and metaboric acid are converted into orthoboric acid by reaction with water, wherein the reactions take place in a suspension medium, wherein for the reversible storage of energy, orthoboric acid is present suspended in the suspension medium, and wherein the suspension medium containing orthoboric acid is brought to a temperature at which water loss occurs via an energy source, wherein for the reversible thermochemical release of energy boric oxide and/or metaboric acid are present suspended in a suspension medium, wherein water is added to the suspension medium containing boric oxide or metaboric acid or boric oxide and metaboric acid so that the reaction proceeds to orthoboric acid, wherein the hea