Application of the Calcium Looping Process for Thermochemical Storage of Variable Energy

The calcium looping (CaL) process, which exploits the reversible calcination of calcium carbonate, has been proposed as a solution to the challenges facing deployment of concentrated solar power (CSP). As an extension of the work undertaken to date, this project proposes a novel configuration of the CSP-CaL process which may offer advantages over other proposed configurations, including a reduction in process equipment requirements, elimination of pressure differentials between vessels, and a reduction in compression duty during the energy discharge period. The results obtained through process simulation indicate that the proposed process can achieve round-trip efficiencies in the range of 32–46% and energy storage densities in the range of 0.3–1.0 GJ/m3. These parameters are strongly dependent on the residual conversion of the CaO sorbent as well as the efficiency of the power cycles used to remove heat on the carbonator side of the process.