Thermoeconomic and exergo-environmental analysis trigeneration system based on waste heat recovery and geothermal energy with post-combustion CO₂ capture

The current paper uses the waste heat of flue gas and combines it with geothermal energy to present a new trigeneration framework for the simultaneous generation of electric power, heating power, cooling power, and carbon dioxide. The system consists of an ammonia Rankine cycle, liquefied natural gas regasification, modified Kalina cycle, and carbon dioxide capture unit, which are integrated and connected. This system is evaluated through thermo-economic and exergo-environmental evaluations. Using total exergy analysis, irreversibility and the location of the most exergy destruction is determined, and solutions are provided to reduce it. Three scenarios of single generation, combined heat and power generation, and trigeneration are compared according to each case's energy efficiency and exergy rate. The Kalina cycle is integrated to allow the concurrent production of electric power, cold water, and hot water. The results showed that the new process has 15.09 % electrical efficiency, 28.93 % energy efficiency, and 56.19 % exergy efficiency. The optimized process design reached an exergy efficiency rate of 78.92 % above the baseline system, with the minimized parameters of effectiveness factors of environmental damage (EFED) of 0.154 along with the economical levelized cost of energy (LCOE) at 0.154 $/GJ under the optimized configuration. Besides, the total annual cost is 8,201,584 $, and the levelized energy cost is 0.1793 $/kWh. The main novelty lies in the striking performance of the proposed process in minimizing the total annual cost and levelized energy cost.