Exergy, exergoeconomic, and exergoenvironmental analyses of novel solar- and biomass-driven trigeneration system integrated with organic Rankine cycle

Abstract

This study proposes a combined cooling, heating, and power (CCHP) system driven by biomass and solar energy integrated with an organic Rankine cycle (ORC). Its exergy, exergoeconomic, and exergoenvironmental performances are investigated. First, the thermodynamic parameters of each material and energy flow for the proposed CCHP system are simulated using Aspen Plus. Second, the exergy and exergoeconomic performances of the system are investigated, and an exergoenvironmental analysis of the system is performed. The results show that the unit exergy costs (UEC) of domestic hot water, electricity generated by an internal combustion engine (ICE) and the ORC, and chilled/heated water under summer/winter conditions are 2.742/2.742, 6.713/6.629, 12.930/12.930, and 27.100/12.530 MW/MW, respectively, with corresponding unit exergoeconomic costs (UEEC) of 41.11/41.11, 124.40/139.20, 181.80/181.80, and 507.10/302.60 USD/MWh, respectively. Meanwhile, the corresponding environmental impact rates per exergy unit are 0.616/0.616, 2.988/3.023, 0.030/0.030, and 6.567/3.072 mPts/MJ, respectively. The results highlight the urgency to prioritize improvements to the solar collector performance to reduce the UEC of electricity generated by the ORC. The absorption chiller/heater, heat exchanger, and ICE exhibit significant potential for enhancing their exergoeconomic performance. Additionally, the gasifier, ICE, and ORC can be optimized to mitigate their environmental impact with relatively minimal exertion.