ELECTRO-THERMAL ENERGY STORAGE SYSTEM WITH IMPROVED EVAPORATIVE ICE STORAGE ARRANGEMENT AND METHOD FOR STORING ELECTRO-THERMAL ENERGY

摘要

A system and method for electro-thermal energy storage is described. The system has a charging cycle (10) for providing thermal energy to a hot thermal storage arrangement (18, 20, 22) and an evaporative ice storage arrangement (24) and a discharging cycle (30) for generating electricity by retrieving the thermal energy. The evaporative ice storage arrangement (24) comprises a heat exchanger (14, 36), an ice slurry storage tank (26), a vacuum evaporation chamber (28) and a slurry heat exchanger (40). The evaporative ice storage arrangement (24) of the present invention functions as a dedicated cold storage for the electro-thermal energy storage system. The cold storage is realized by producing an ice-water mixture during charging of the storage, and using the stored ice-water mixture to condense the working fluid during the discharge cycle (30). Use of this subtriple-point evaporation arrangement functions to increase the round-trip efficiency of the ETES system through minimising the maximum temperature difference between the working fluid and the thermal storage medium during operating cycles.