Energy, exergy, economy, and environmental (4E) analysis of a multi-generation system composed of solar-assisted Brayton cycle, Kalina cycle, and absorption chiller

Abstract

• A combined cooling, heat, and power production system is proposed. • The system injects 4.67 MWh electricity to the grid. • The roundtrip exergy efficiency of the system is 42.1%. • Lifetime costs of the system is 2.04 million dollars. • Utilizing the system leads to 75.4% reduction in nitrogen oxides reduction. Employing multi-generation concept and renewable energy sources are two promising tools to overcome exorbitant consumption of fossil fuels. In this paper, the aforementioned techniques have been used to supply the energy demand of a commercial building. To do so, a novel tri-generation system is proposed and analyzed from energy, exergy, economic, and environmental points of view. This multilateral analysis provides a comprehensive view for the owner and decision makers whether the energy conversion system has a sustainable design from several points of view. Brayton cycle assisted with solar energy, bottoming Kalina cycle, absorption chiller, and waste heat recovery exchanger are used to supply the energy demand. Energy analysis reveals that the plant must be connected to the grid in order to meet the gap between absorption chiller production rate and the user cooling demand. The annual energy export to the grid equals to 4670 MWh while 2294 MWh electricity must be imported. Considering the exergy analysis, round-trip exergy efficiency of the plant is 42.11%. Brayton cycle has the highest share in the exergy destruction and corresponds to 93.00% of the annual exergy destruction. Based on the economic evaluation, the net system costs during its life cycle are 2.02 M$. Finally, sensitivity analysis is conducted to investigate the change in system performance by varying the key design parameters.