Design and operational performance maps of calcium looping thermochemical energy storage for concentrating solar power plants

Calcium-looping thermochemical energy storage associated to concentrating solar plants appears as promising technology given its potential to increase the storage period and energy density of the stored material. Up to now, research efforts focused on the global efficiency of the TCES associated to different power cycles under fixed modes of operation: day or night. However, TCES will never operate under a stationary situation but will experience different operation points to adapt to solar availability and energy demand from the power cycle. The aim is to analyse the influence of those variables which define the operation points, under energy storage and release modes, in the design of the heat exchangers network, storage tanks and reactors involved in the TCES system. The equipment in the conceptual plant have been modelled accounting variable storage/discharge fractions in the mass balances. The results show a suitable capture efficiency, quantifies the stored power and define the size and performance of the heat exchangers required to operate the system. The behaviour of each heat exchanger and their relevance in heat integration with a power plant is derived. The novelty relies in the analysis of potential situations arising from different combinations of charge/discharge fractions of storage tanks. •A CaL – CSP model is analysed under two operation modes: energy storage/release.•The stored power, up to 20 MW, is quantified in a large number of situations.•The required size to store CaO and CO2 during 15 h is 1280–10,436 m3.•The carbon capture efficiency limited by operational restrictions is 96.15%.•The heat exchangers size is influenced by storage tanks charge/discharge fractions.