A Treament for Thermal Efficiency Improvement in the Brayton Cycle

抄録

As a treatment for thermal efficiency improvement in the Brayton cycle, the following items were discussed on regenerative and/or isothermal compression processes. (a) An equivalent illustration method for the Brayton cycle on the T-S diagram, and (b) the introduction of a new special characteristic value φ, which expresses the possibility and the degree of thermal efficiency improvement, and (c) the influences of different working fluids on thermal efficiency. Next, the liquid-compressed supercritical-pressure cycle was taken up as a cycle that approximately realizes the isothermal compression process, and the optimum working fluid, which maximizes thermal efficiency, was discussed using NH₃, SO₂, CO₂, or H₂O as the working fluid. As a result, the advantage of CO₂ over the other fluids in thermal efficiency was clarified.