Concept of the thermal integration of the compressed air energy storage system with the power plant

摘要

The article presents the concept of an innovative hybrid system that integrates the compressed air energy storage system with a conventional power plant. Using simple mathematical models, the proposed hybrid system was compared with the classic adiabatic system. The article also presents the results of more detailed thermodynamic analyzes for the compressed air energy storage system, which has been thermally integrated with the 600 MW coal-fired power plant. The first stage of integration enables the storage system to utilize the heat of compressed air (air cooling) for condensate heating, which results in partial replacement of the low-pressure regeneration of power unit and subsequently power increase. The second stage of integration allows to heat the air during discharging of the energy storage system before air expanderusing the heat of superheated steam which is directed from the steam turbine bleeding to the high pressure regeneration exchanger. Such organized integration, although contributing to the decrease in the efficiency of the power unit, allows to eliminate the need for gaseous fuel in the energy storage system, as in the case of diabatic systems, or heat storage, as in the case of adiabatic systems.Three variants of the hybrid system were analyzed. The evaluation of hybrid system variants was made using the energy storage efficiency defined in the article.