Comprehensive performance analysis of cold storage Rankine Carnot batteries: Energy, exergy, economic, and environmental perspectives

Rankine Carnot batteries have demonstrated promise as a viable solution for electricity storage due to their high energy density at low temperatures. A specific variant of these batteries, known as the Cold Storage Rankine Carnot Battery (CSRCB), utilizes a vapor compression refrigeration (VCR) unit to store cold energy at sub-ambient temperatures. In this paper, three different configurations of CSRCB are constructed: the Basic CSRCB (B-CSRCB), CSRCB with a recuperator in VCR (R-CSRCB), and CSRCB with a recuperator in VCR and a preheater in ORC (RP-CSRCB). The system is analyzed from four perspectives: energy, exergy, economic, and environmental (4E). The impact of key parameters, such as heat source temperature, ambient temperature, and pinch point temperature, on the system's performance is evaluated. The results indicate that the RP-CSCBR configuration outperforms others in terms of energy, exergy, and economic analysis. The evaporator in ORC-subsystem is the component with the largest exergy loss. When the three configurations of CSRCB achieve the maximum exergy efficiency under different conditions, the ORC-subsystem evaporator accounts for 41.9 %, 41.9 % and 17.6 % of the exergy loss of B-CSRCB, R-CSRCB and RP-CSRCB, respectively. The lowest levelized cost of storage (LCOS) can be obtained when the system is operating at high heat source temperature, low ambient temperature and small pinch temperature difference. The environment assessment results show that the changes of the key parameters of the system have different effects on the annual emission reduction (AER) and total equivalent warming impact (TEWI) of CSRCB with different configurations.