Study on Working Fluids Selection of a Solar-Assisted Carnot Battery System for Offshore Wind Power Platform

There is a long-term mismatch between the power generation and electricity demand of offshore wind power generation, and a supporting energy storage system is required to connect and consume the power of the offshore wind power platform. In this paper, a low-investment solar-assisted Carnot battery energy storage system is designed for offshore wind power platforms, which uses electricity generated from renewable energy (solar energy) to drive a heat pump cycle to store thermal energy in a phase change material in a thermal storage tank. The thermal energy is then transferred to the ORC cycle to generate stable electrical power when needed. In this paper, the thermodynamic model of the system is established, and the boundary conditions are designed according to the actual environment of the offshore wind power platform, and the most suitable circulating working fluid is selected from many aspects. When the low temperature heat pump cycle uses acetone refrigerant and the organic Rankine cycle uses R365mfc refrigerant and when the heat storage temperature is from 130 °C to 160 °C, the power ratio is 89.1% to 130.9%, the equipment cost is low, and its efficiency is low. Therefore, acetone and r365mfc may be the best refrigerant choice.