Environmental assessment and CO2emissions of Brayton cycle configurations based on exergo-sustainability, economic and ecological efficiency using multi-criteria optimization technique

Abstract

The performance indicators of Brayton cycle configurations (BCY) for the topping cycle application are presented. The indicators include exergy efficiency, ecological efficiency, sustainability index, environmental impact, and economic parameters. The study's objective is to access the key indicators of sustainability and investment cost to provide valid information for the choice of GT configuration as topping cycles. Five BCY configurations (Model 1 to Model 5) were studied. The maximum exergy efficiency of 28 % was obtained across the studied models. In addition, the waste exergy ratios, environmental effect factors, and CO2 emissions were determined for each model. The CO2 emissions were found to vary from 102.8 to 168 kg/MWh. Model 1 and Model 5 had the highest payback periods of 2.3 and 3.6 years, respectively, with the least unit cost of energy. Similarly, the highest cost of investment was obtained with Model 5. Results from the TOPPIS analysis show that the closeness to the final positive ideal solution varied from 0.218 to 0. 56 across the BCYs. The best model close to ideality was model 5 and thus ranked first and based principally on economic, technical, and environmental sustainability. Furthermore, the optimization results show that there are prospects for system retrofitting.