Exergoeconomic, exergoenvironmental analysis and multi-objective optimization of a novel combined cooling, heating and power system for liquefied natural gas cold energy recovery

Abstract

This paper designs and investigates a novel combined cooling, heating, and power (CCHP) system for effectively utilizing liquefied natural gas (LNG) cold energy and waste heat of exhaust gas based on thermodynamic, exergoeconomic and exergoenvironmental analysis. The effects of the mass flow rate of the ORC-I’s working fluid, turbine 1 inlet temperature, compressor and pump outlet pressure and the turbines’ isentropic efficiency on the system performance were investigated. In addition, the non-dominated sorting genetic algorithm II (NSGA-II) and the particle swarm optimization (PSO) were employed to optimize the CCHP system with multiple objectives, respectively, to find the optimal operating conditions of the system. The optimization results showed PSO was superior for the multi-objective optimization of this novel CCHP system compared to NSGA-II, showing the exergy efficiency, product unit cost and product unit environmental impact of 70.20%, 21.50 $/GJ and 57.91 mPts/GJ, respectively.