Heat compensation type carbon dioxide mixed working medium energy storage system with cascade heat storage function

Abstract

The invention discloses a heat compensation type carbon dioxide mixed working medium energy storage system with a cascade heat storage function. The heat compensation type carbon dioxide mixed working medium energy storage system at least comprises a cascade heat storage subsystem, a carbon dioxide mixed working medium energy storage subsystem and a heat compensation subsystem. The cascade heat storage subsystem comprises a plurality of stages of heat storage units with different temperatures, each stage comprises a heat storage heat exchanger, a high-temperature heat storage medium storage tank and a low-temperature heat storage medium storage tank, and heat energy utilization is optimized. The carbon dioxide mixed working medium energy storage subsystem comprises a high-pressure storage tank, a low-pressure storage tank, a compressor unit and an expansion unit, and efficient compression in the energy storage stage and efficient expansion in the energy release stage are achieved. The heat compensation subsystem is arranged between the highest-temperature-stage heat storage unit and the expansion unit, heat compensation is conducted on the carbon dioxide mixed working medium through the photo-thermal subsystem and / or industrial waste heat, the temperature of the carbon dioxide mixed working medium is increased, and the circulation efficiency of the system is improved. In addition, the system further comprises a waste steam recovery subsystem, and the evaporation efficiency and the energy utilization efficiency are further improved through high-temperature waste steam exhausted by the turbine.

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