AbstractThe application of Glauber salt as a latent heat storage material is a difficult technical problem owing to the separation of the coexisting phases (stratification) during melting. In order to avoid stratification and to improve the heat transfer in the course of the charge and discharge, a new storage type called ‘GLS’ was developed, in which the heat is transferred in a closed container to the latent heat storage material by means of the vapour of a heat transfer liquid. Surface‐active materials which were added to the storage materials produce optimum conditions for the heat transfer and material transport during the heat transfer processes.Under the conditions of the GLS storage unit on application of Glauber salt, constant storable amounts of energy were found which are in good agreement with the theoretical values. The heat storage can be performed with high energy densities in narrow temperature differences and with high power of the transferred