In order to store thermal energy at a low temperature, three types of latent heat storage systems are presented and compared. The storage systems are a direct contact latent heat storage system, a latent heat system with an encapsulated phase change material (PCM) and a water reservoir with a PCM jacket. These heat systems are utilized for an efficient use of renewable energies and low-temperature waste heat. The storage medium is a salt hydrate with a melting point of 27 degrees C. This work presents the three concepts including corresponding applications and a discussion of the experimental results.