Energy, exergy, and exergoeconomic analysis of a novel integrated energy system based on parabolic trough solar collectors and LNG cold energy utilization.

This study proposes a novel integrated energy system to reduce the carbon emissions and to achieve efficient utilization of renewable and clean energy. The system features a PTSC coupled sequentially with a recuperative Organic Rankine Cycle and a Kalina Cycle, while also incorporating liquefied natural gas (LNG) to enable combined cooling, heating, and power generation alongside natural gas supply. Initially, the mathematical models are established to conduct energy, exergy, and exergoeconomic analyses for the proposed system. The initial cost and exergy destruction cost are calculated using the cost balance equations. Under the design conditions, the power generation, energy efficiency, and exergy efficiency achieve 14.20 %, 40.97 %, and 13.93 %, respectively. The exergy analysis indicates that the PTSC and Condenser I possess the primary sources of exergy destruction, accounting for 58.49 % and 21.52 % of the total exergy destructions, respectively. The exergoeconomic analysis reveals that the cost rate and average product cost of the proposed system are 2.931$/h and 12.39$/GJ, respectively, which exhibiting an excellent economic competitiveness and a low product cost rate compared to similar systems. The exergoeconomic analysis for the components indicates that Heat exchanger II and Condenser II rank the lowest in terms of fk, suggesting that optimizing these high-cost heat exchangers can reduce their exergy destructions and improve their economic performance. Parametric analysis demonstrates that the exergy efficiency and energy efficiency are increased as solar radiation intensity and thermal oil mass flow rate increasing, however, the cost rate correspondingly rises.