Dynamic performance and sustainability assessment of a PV driven Carnot battery

This study investigates the performance of a Carnot Battery and performs a thermodynamic-based sustainability analysis using different methods. Carnot batteries have two different operational processes, charge and discharge. Electricity generated from a renewable source is used to operate a heat pump and the heat rejected by the heat pump is stored in the battery, which is then used to generate electricity in the Organic Rankine Cycle (ORC) at night and called as the discharge process. Climatic data from the city of Izmir, the third largest city by population in Turkey, has been chosen for the dynamic analysis. Exergy-based sustainability and thermo-ecological cost analyses are performed. The results show that the maximum Coefficient of Performance (COP) of the heat pump system is 4.5, the exergy efficiency can reach 0.78 and its the maximum sustainability index is 4.5. For the discharge process, energy efficiency of the ORC is 0.118 while the exergy efficiency is around 0.49 with a sustainability value of about 2.0.