Multi-level eco-friendly heat recovery process integrated into a gas turbine cycle of an innovative CCHP-desalination system: Assessment and optimization of the thermo-economic-environmental aspects

Concerning the high energy loss associated with benchmark gas turbine cycles and relative irreversibility, research on how this drawback can be controlled and managed for long-term sustainability, enhanced performance, and declined emissions of greenhouse gases is essential. In this context, a novel multi-level thermal recovery method is designed and introduced for a gas turbine cycle, aimed at simultaneously yielding electricity, hot and chilled water, hydrogen, and desalinated water. The planned setup encompasses an ammonia Rankine cycle, an organic Rankine cycle, an absorption chiller, a desalination unit, and a proton exchange membrane electrolyzer, resulting in reduced irreversibility and emissions. The system's capability is examined concerning exergy, energy, environmental, and economic aspects using Aspen HYSYS software. Furthermore, a comparative study is conducted between different optimization scenarios. According to the attained outcomes, maximizing vapor production requires a reduction in seawater flow. Additionally, increasing the seawater flow rate is ineffective in the proposed process, as vapor from the desalination unit drives heat transfer. Regarding the optimizations conducted, the most suitable exergy efficiency is found to be 39.27 %, which corresponds to the exergy-power scenario. Moreover, the optimal net electric power, and cooling and heating loads are calculated at 18,255 kW, 4383 kW, and 15,280 kW, respectively; thus, the optimal energy efficiency is 74.51 %. From economic and environmental perspectives, the optimal cost of energy and CO₂ footprint are 0.76 $/kWh and 0.255 kg/kWh, correspondingly.