Parametric Energy and Economic Analysis of Modified Combined Cycle Power Plant with Vapor Absorption and Organic Rankine Cycle

To meet the escalating electricity demand and rising fuel costs, along with notable losses in power transmission, exploring alternative solutions is imperative. Gas turbines demonstrate high efficiency under ideal International Organization for Standardization (ISO) conditions but face challenges during summer when ambient temperatures reach 40°C. To enhance performance, the proposal suggests cooling inlet air by 15°C using a vapor absorption chiller (VAC), utilizing residual exhaust gases from a combined cycle power plant (CCPP) to maximize power output. Additionally, diverting a portion of exhaust gases to drive an organic Rankine cycle (ORC) for supplementary power generation offers added efficiency. This integrated approach not only boosts power output but also minimizes environmental impact by repurposing exhaust gases for additional operations. This study presents a detailed energy and economic analysis of a modified combine cycle power plant, in Kotri, Pakistan. R600A is used as organic fuel for the ORC while LiBr-H2 O solution is used for the VAC. Two performance parameters, efficiency and energy utilization factor, Four energetic parameters, Work output of ORC, modified CCPP, original CCPP and cooling rate, and one economics parameter, payback period were examined under varying ambient conditions and mass fraction of exhaust gases from outlet of a gas turbine (ψ). A parametric investigation was conducted within the temperature range of 18°C to 50°C, relative humidity between 70% and 90%, and the ψ ranging from 0 to 0.3. The findings reveal that under elevated ambient conditions (40°C, 90% humidity) with ψ at 0, the Energy Utilization Factor (EUF) exceeds 60%. However, the ORC exhibits a low work output of 100 KW alongside a high cooling load of 29,000 kW. Conversely, the modified system demonstrates an augmented work output of approximately 81,850 KW compared to the original system’s 78,500 KW. Furthermore, the integration of this system proves advantageous across all metrics. Additionally, the payback period of the system is contingent on ambient conditions, with lower conditions correlating to shorter payback periods and vice versa. © 2024 The Authors. Published by Tech Science Press.