Assessment of a new combined thermal and compressed energy storage coupled with an absorption power cycle: Thermodynamic study

Energy storage technologies highly flourish in past years along with the quick progress of renewable energies. Compressed air energy storage has captured the world attention due mainly to its eco-friendliness, long lifetime, safety and good economic benefits. In the paper a new hybrid energy storage system is put forward. It comprises a combined thermal-compressed air energy storage and an ejector-based superheated Kalina cycle. Mathematical model of the hybrid energy storage system is developed for thermodynamic analysis and parametric study is conducted to examine the effects of some key parameters on the performance of new system. The results demonstrate that the separation pressure enjoys an optimum valve firstly and then at a higher separation temperature the increase of it gives a monotonical increase in the round trip efficiency. As the ammonia mass fraction increases, the round trip efficiency increases first and decreases with existing an optimum value. In general, the new hybrid system enjoys 6.13–9.32% higher round trip efficiency than the baseline standalone system. Therefore, the proposed system has a positive potential for storing renewable power in large scale in favour of increasing penetration level of renewable energies.