Heat exchanger modeling and exergoeconomic analysis of two solar-driven combined power and cooling systems: a comparative study of ORC and Kalina configurations
摘要
This study presents exergoeconomic assessment of two solar-driven combined power and cooling systems. The analysis incorporates detailed thermo-hydraulic design of heat exchangers using actual thermal loads and geometries, ensuring accurate estimation of performance and cost. Two configurations are compared: Configuration C1, featuring two organic Rankine cycles (ORCs), and Configuration C2, where the second ORC is replaced by a Kalina cycle (KC). A component-level exergy cost evaluation reveals critical insights into the economic and thermodynamic behavior of each system. The study finds that evaporators in cooling system dominate in size due to their lower heat transfer coefficients, while components such as absorbers and solution heat exchangers benefit from higher overall heat transfer coefficients, allowing for more compact designs. C1’s ORC-II hosts the largest and most thermally demanding heat exchangers, whereas C2’s KC configurations feature a compact HRVG but a larger condenser due to higher heat duty and lower overall heat transfer coefficient. The KC demonstrates lower exergy destruction than ORC-II, making it thermodynamically superior. Cost analysis shows HRVGs are the most expensive components due to significant exergy destruction, especially in C1. The solar collector remains the primary cost and inefficiency driver, contributing over 87% to capital costs in both configurations. C2 outperforms C1 with higher net power output (9423.41 kW vs. 8791.25 kW), lower exergy destruction, total cost rates, and greater economic feasibility, evidenced by shorter payback periods and reduced investment needs.