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Thermodynamic analysis of a novel compressed carbon dioxide energy storage system with low‐temperature thermal storage
Author(s) -
Zhang Yuan,
Yao Erren,
Zhang Xuelai,
Yang Ke
Publication year - 2020
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.5387
Subject(s) - exergy , energy storage , thermal energy storage , exergy efficiency , compressed air energy storage , renewable energy , process engineering , heat pump , environmental science , computer data storage , thermal , mechanical engineering , nuclear engineering , materials science , thermodynamics , engineering , computer science , electrical engineering , heat exchanger , power (physics) , physics , operating system
Summary Research projects on new electrical energy storage (EES) systems are underway because of the role of EES in balancing the electric grid and smoothing out the instability of renewable energy. In this paper, a novel compressed carbon dioxide energy storage with low‐temperature thermal storage was proposed. Liquid CO 2 storage was employed to increase the storage density of the system and avoid its dependence on geological formations. Low‐temperature thermal energy storage technology was utilized to recycle the heat of compression and reduce the challenges to system components. The system configuration was introduced in detail. Four evaluation criteria, the round trip efficiency (RTE), exergy efficiency ( η Ex ), thermal efficiency ( η TE ), and energy density ( ρ E ) were defined to show the system performance. Parametric analysis was carried out to examine the effects of some key parameters on system performance and the genetic algorithm was adopted for system optimization. The calculated results show that, for the novel EES under the basic working condition, its RTE is 41.4%, η TE is 59.7%, η Ex is 45.4%, and ρ E is 15 kWh m −3 . The value of ρ E increases with the increasing pump outlet pressure for a fixed value of pressure ratio, and the changes of RTE, η TE , and the total exergy destruction of the system ( E D,total ) with pump outlet pressure are complicated for different values of pressure ratio. When both pressure ratio and pump outlet pressure are high, the values of RTE and ρ E can be maximized whereas the value of E D,total can be minimized. Besides, no matter how pump outlet pressure and pressure ratio change, the exergy destruction of the system mainly come from compressors and regenerators, which accounts for about 50% of the total exergy destruction.