Systematic Evaluation of Brayton Battery Concepts for Multi-Purpose Energy Applications

Kurzfassung

Brayton batteries offer substantial potential for enhancing energy storage efficiency. However, there remains a significant gap between theoretical and practically achievable performance. These differences are mainly due to turbomachinery limitations: current compressor discharge temperatures are restricted to 400-500 °C, and isentropic efficiencies for large-scale units range between 80-90 %, leading to considerable heat losses. As this waste heat cannot be fully utilized for electricity generation alone, optimizing system efficiency requires not only appropriate topology and parameter selection but also broadening functionality beyond pure electricity production. This study systematically analyzed over 200,000 Brayton battery configurations using Ebsilon Professional®. The investigation covered four operational modes: electricity-only; combined electricity and heat; combined electricity and cooling; and combined electricity, heat, and cooling - each considered both with and without waste heat utilization. Electric-only efficiencies ranged from 20 % to 50 %, with better performance at 625 °C compared to 450 °C. Adding heat or cooling recovery improved overall efficiency but reduced electric output. Simultaneous generation of electricity, heat, and cooling was not feasible within the studied framework. The most promising configurations were predominantly air-based systems with or without charging line recuperators and various heat exchanger placements. These topologies will be further explored through dynamic simulations focused on thermal energy storage. A key finding is that effective heat exchanger integration is critical. Only specific combinations of parameters and layouts proved viable. This work stands out due to its scale and systematic methodology, enabling better identification of optimal Brayton battery solutions and highlighting their potential for flexible, efficient energy systems.