Synergetic performance of gas turbine combined cycle unit with inlet cooled by quasi-isobaric ACAES exhaust

Gas power generation units are challenged with peak regulation in the new power system characterized by high proportion of renewables. In aim to enhance the part-load performance and the peak-regulation capacity of gas turbine combined cycle (GTCC) power units, a synergetic power system of GTCC integrated by an isobaric and adiabatic compressed air energy storage (IACAES) was proposed, where the compressor inlet air in the gas turbine was directly mixed and cooled by the ACAES exhaust. Based on the demand load distribution of a GTCC unit and the off-design performance, the parameters of the IACAES were designed for the proposed synergetic system (SS), and comparatively for the benchmark integrated system (BS) without compressor inlet cooling. The peak-regulation performances of the proposed synergetic system were investigated and compared with those of the standalone GTCC as well as the benchmark system. The case study in a 67.3 MW GTCC indicates that, in the range of the ambient temperature from 283.15 to 308.15 K, the GTCC operative efficiency considerably enhances by averagely 0.943% resulting from the power shifting. The IACAES discharging power and roundtrip efficiency in SS are 10.5% lower than those in BS. An average negative gap of system efficiency in SS reaches 0.199% versus BS. However, GTCC inlet cooling by IACAES exhaust enhances the power capacity of the unit averagely by 1330.88 kW, and the peak-regulation capacity increases averagely by 10.59% compared to that in the standalone GTCC. The peak-regulation capacity enhances by 1.98% versus BS. The synergetic cooling effect weakens with the reduction in the ambient temperature and the charging air pressure.