Energy Efficiency Lab (EFEN) will open a new applied research direction in the University Politehnica of Bucharest. The main objective of this laboratory is the development of researches geared to finding optimal methods to increase energy efficiency in buildings, thermal processes and thermal power plants. Also, EFEN lab will undertake research and will provide solutions even for the others CAMPUS laboratories (Intelligent and Ecological Buildings Lab, Geothermal Technologies and Sources Lab, Solar Technology Lab etc.). Thermal energy storage is an older concern of engineers in the field, but research in two-phase storage systems is a relatively new direction globally and nationally almost nonexistent. In the EFEN lab, through the built pilot installation, it is desired to study the thermal storage capacity for different types of phase change materials and various types of heat exchangers. The main goal of the research is to obtain an efficient thermal energy storage system, which can be multiplied on a commercial scale. At the same time, it is desirable the opening of international collaborations with universities carrying out research in this area for conducting experience exchange.