Evaluating the feasibility of a novel Allam cycle for co-generating power and water in hot regions

Abstract

The efficient performance of the Allam cycle deteriorate in hot regions, where water scarcity is a common issue. To overcome these challenges, a novel modification of the Allam cycle is proposed to simultaneously generate power and water. In this study, the seawater evaporation is utilized to provide cold sink for CO2 liquefaction, and the heat from compressing the vapor separated during seawater evaporation is utilized in a multi-effect evaporation desalination subsystem to produce freshwater. Detailed techno-economic analyses are conducted to assess the feasibility of the proposed system. The calculations indicate that the net efficiency of the new system is 49.11 %, representing a 6.18 % increase compared to the original system. Additionally, the system has the capacity to produce 292.64 kg/s of freshwater. For every 1 °C rise in ambient temperature, freshwater production increases by 0.6 %, and efficiency decreases by 0.06 %. Although the proposed system incurs an investment cost increment of approximately 5.89 %, it is projected to recoup this cost within less than 2.1 years. Moreover, the parametric analyses indicate that the proposed co-generation system is highly competitive in regions with higher electricity prices and water prices. These findings contribute to the application and promotion of Allam cycle technology in hot and water-stressed regions.