Currently, the energy sector is facing a great challenge of transformation towards climate neutrality. It is possible mainly through distributed smart grid based on renewable energy sources, which are inherently inflexible. Therefore, it is necessary to improve the energy sector by develop of storage technologies. Here we would like to present thermo-mechanical energy storage in m-CAES (Compressed Air Energy Storage/System) technology. In the existing state-of-art, both scientists and engineering groups indicate barriers and limitations in m-CAES development in poorly recognised nature of air expansion dynamics. Existing of storing-expansion pressure gap, problem with heat transfer and storage and unstable power generation through turbines results in low roundtrip efficiency 30-50% . We discover that the controllability of expansion process dynamics is improved by exploiting the inertia of the elements in multiple piston expander with air injection and pulse heating by Thermal Energy Storage (TES) . In our research we applicate the theory of impinging pressure of injected air into piston wall by prof. John Hutchison  to novel strategy of Mechanical Energy Storage (MES) discharge. In addition, the achievements of prof. Alto Steinfeld concerning thermal energy storage in granular/phase change materials are used to study the place of heat supply to the system . We employ the above mention two approaches to increase roundtrip efficiency of m-CAES to 70-75% or more.
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