The topic of the thesis concerns a system installed at the faculty of Engineering in Ljubljana, composed of a solar air collector and a LHTES (latent heat thermal energy storage) unit, constituted by PCM (phase changing material) plates, which is used for office ventilation. The system has been designed to carry out experiments and to verify the savings that could be obtained for indoor ventilation. The purpose of the thesis is to investigate directly the system with temperature and velocity measurements and to compare the data obtained through experimentation with the results of the simulated system in TRNSYS software with the purpose of validating the results of the software.