INVESTIGATION OF A MASSIVE ELECTRICITY STORAGE SYSTEM BY MEANS OF A GEOTHERMAL HEAT TRANSFER PROCESS INVOLVING CO2 TRANSCRITICAL CYCLES

asme-orc2015 Tracking Number 10

This work presents a specific application of the Rankine cycle and heat pump technologies: electricity storage. A multi-megawatt thermo-electric energy storage based on thermodynamic cycles is studied as a promising alternative to PSH (Pumped-Storage Hydroelectricity) and CAES (Compressed Air Energy Storage) systems. As a preliminary work, the main objective is to assess the performances of the massive storage technology based on transcritical CO2 heat pump for charging and transcritical CO2 Organic Rankine Cycle for discharging, with power output in the 1-10 MWe range. The general concept of the system is presented, along with its thermodynamic modeling. A parametric analysis is carried out showing that it is possible to reach roundtrip efficiencies up to 53% that are competitive with other technologies. This work also shows the strong dependency between the different parameters of the system, and how an economic optimization will have to take all the subcomponents into account.