The invention provides a closed compressed
carbon dioxide heat pump energy storage system and a use method thereof, and the
system is additionally provided with a variable volume gas
storage tank, an actuating mechanism and a plurality of regulating valves on the basis of a traditional compressor, an expansion
machine, a
heat exchanger and a heat regenerator. The variable-volume gas
storage tank is connected to the outlet side of the expansion
machine, and the volume of the variable-volume gas
storage tank is changed through driving of the executing mechanism, so that the overall pressure and working
medium density of the
system are rapidly adjusted on the premise that the total
mass of working media of the system is not changed, and rapid and efficient lifting of loads is achieved. And meanwhile, the volume of the gas storage tank can be actively expanded to the maximum when the system is
shut down, so that the stagnation pressure of the system is rapidly reduced to a safe range, and the
overpressure risk of low-pressure side equipment is effectively avoided. The closed type
carbon dioxide energy storage system solves the technical problems that an existing closed type
carbon dioxide energy storage system is low in load adjusting speed, low in efficiency and high in shutdown pressure, and has the advantages of being fast in response, high in energy efficiency and good in safety.