Multi-dimensional sustainability assessment and process optimization of toluene diisocyanate production: Integrating life cycle assessment, techno-economic analysis, and exergy analysis

Worldwide rapid industrialization has led to substantial low-temperature waste heat generation, posing both environmental challenges and opportunities for energy recovery. Organic Rankine Cycle (ORC) systems have emerged as a promising technology for converting such low-grade waste heat into useful power due to their ability to operate with organic working fluids at relatively low temperatures. This study presents a comprehensive energetic and exergetic analysis of three ORC configurations: Basic, Reheat, and Regenerative ORC using environmentally sustainable refrigerants with a low Global Warming Potential (GWP < 10). A numerical simulation is performed by Python programming to solve the mass, energy, entropy, and exergy balance equations of the ORC configurations to evaluate the performance of six low-GWP refrigerants: R-1243zf, R-1234yf, R-1234ze(E), R-1224yd(Z), R-1233zd(E), and R-1336mzz(Z). The investigation specifically assessed the impact of turbine inlet pressure (1.0 – 2.5 MPa) and pump inlet pressure (0.8 – 2.0 MPa) on key performance parameters: net power output, thermal efficiency, exergy efficiency, and total exergy destruction. The analysis reveals that R-1243zf consistently outperforms among other refrigerants across all configurations followed by R-1234yf, R-1234ze(E), R-1224yd(Z), R-1233zd(E), and R-1336mzz(Z). For all refrigerants, the optimal performance was achieved at the higher turbine inlet pressure of 2.5 MPa and the lower pump inlet pressure of 0.8 MPa. At the optimum pressures, R-1243zf exhibited strong performance across configurations: the Reheat ORC maximized net power output (33.8 kW), the Regenerative ORC maximized thermal efficiency (10.6%), and the Basic ORC achieved the highest exergy efficiency (36.0%). Under these optimal pressure conditions, R-1243zf demonstrated superior performance in the Basic ORC configuration, yielding the highest exergy (36.0%) efficiency and an effective balance of thermal efficiency (10.0%) and net power output (32.6 kW). The novelty of this study lies in the quantitative screening of low-GWP refrigerants (GWP < 10) across three ORC configurations, establishing a clear performance hierarchy and identifying the optimal fluid-architecture pairing (R-1243zf in a Basic ORC) for practical implementation under specified pressure conditions. • Energy and exergy analysis of Basic, Reheat, and Regenerative ORCs • R-1243zf shows highest power output and efficiency among six low-GWP fluids • Optimal performance achieved at 2.5 MPa turbine and 0.8 MPa pump inlet pressure • Reheat ORC maximizes power, while Regenerative ORC improves efficiency

Energy and exergy analysis of complex gas-steam systems powered by a mixture of biogas and hydrogen

Thermo-economic and advanced exergy analysis of a pumped-hydro system coupled with compressed supercritical CO2 storage

Thermodynamic performance analysis and advanced exergy analysis of a transcritical CO2 energy storage system coupled with methanol production

Energy and exergy analysis of a hybrid active-passive PV cooling system with MgO-enhanced PCM, metallic microchannels, and TEGs

Advanced exergy analysis of the high-temperature PEMFC system integrated Kalina cycle with concentrating photovoltaic (CPV)

This study presents the long-term performance of a 3.3 kWp semi-transparent photovoltaic (STPV) system using five years (2017-2021) of operational data collected in Gödöllő, Hungary. A comprehensive 4E (energy, exergy, economic, and environmental) framework is applied to quantify system performance under real climatic conditions. The system generated an average yearly electricity production of 2490 kWh, with variability driven by irradiance and temperature fluctuations. Exergy analysis based on Petela model revealed average exergy efficiencies significantly lower than energy efficiency due to spectral mismatch and the partial transmittance inherent to the STPV design. Environmental assessment was conducted using updated life-cycle emission intensities (28-100 g CO 2 eq/kWh and 40-110 g CO 2 eq/kWh), resulting in an embodied carbon range between 1.74 and 6.85 tonnes CO 2 eq across the two literature scenarios. Under three grid emission scenarios (0.35, 0.25, and 0.15 kg CO 2 eq/kWh), carbon payback time (CPT) ranges from 2.0 to 18.3 years. Economic evaluation yielded a levelized cost of electricity (LCOE) ranging from €0.095 to €0.117 per kWh, with a simple payback period of 9.5-11.7 years. The results demonstrate that STPV systems can achieve carbon neutrality within their operational lifetime under grid conditions, although environmental performance remains sensitive to future decarbonisation pathways. The proposed framework provides reproducible methodology for evaluating STPV systems using long-term empirical datasets. • Five-year operational analysis of a 3.3 kWp semi-transparent PV system. • Comprehensive 4E framework applied: energy, exergy, economic, and environmental. • Average annual electricity generation reached 2490 kWh under real climate conditions. • LCOE ranges from €0.095–0.117 kWh with a payback period of 9.5–11.7 years. • Carbon payback time varies between 2.0 and 18.3 years depending on grid emissions. • Results confirm long-term viability of STPV systems for BIPV applications.

Retraction notice to “Exergy analysis of a fuel cell power system and optimizing it with Fractional-order Coyote Optimization Algorithm” [Energy Rep. 7 (2021) 7424–7433

A comprehensive review of exergy analysis in sustainable engineering systems: Fundamentals, methods, applications, and challenges

Abstract This study presents a sustainability-focused assessment of previously developed auto-cascade refrigeration (ACR) models using exergy-based parameters, highlighting their performance not only in terms of energy and exergy analyses but also through sustainability indicators reported in the literature. Unlike many studies that focus solely on thermodynamic performance, the present work also evaluates the environmental and sustainability impacts of four modified cascade refrigeration (MCR) configurations, including the ejector-enhanced MCR (MECR) cycle. A binary refrigerant mixture of R170/R290 is used in the low-temperature cycle (LTC), and R1234yf in the high-temperature cycle (HTC). In the LTC, the use of low-GWP refrigerants with flammable characteristics poses a risk of elevated compressor discharge temperatures, particularly at low evaporation temperatures. To mitigate this risk, the refrigerant mixture is precooled via the cascade cycle before entering the separator, thereby reducing the compressor discharge temperature. As a result, the compressor discharge temperature is reduced by 35.1% in the MCR-1 and MCR-3 configurations and by 36.9% in the MECR configuration. Based on data reported in the literature, MCR-2 configuration exhibits improvements in exergy efficiency ranging from 9.3 to 55.5%, whereas the MECR cycle achieves increases between 11.3 and 58.2%. Furthermore, the MECR cycle reduces the ecological and environmental effect factors by up to 17.9% and 23.8%, respectively, compared to the MCR-2 configuration, while increasing the exergetic sustainability index by up to 31.2%. These findings demonstrate that the previously developed models provide significant improvements not only in thermodynamic performance but also in sustainability metrics, extending their applicability beyond energy and exergy-based analyses.

This article presents a comprehensive thermodynamic analysis of renewable energy conversion systems, with particular emphasis on solar photovoltaic (PV) cells, concentrating solar power (CSP) systems, wind turbines, and thermoelectric generators (TEGs). We examine fundamental Carnot efficiency limits governing heat engines and derive modified efficiency expressions applicable under finite-time thermodynamic (FTT) constraints. Entropy generation minimization (EGM) techniques identify dominant irreversibility sources and guide design improvements. Our analysis demonstrates that CSP parabolic dish systems operating at concentration ratios C = 800–1200 achieve exergetic efficiencies of 40–44%, approaching the Curzon-Ahlborn ceiling of 38.8%. Cascaded Bi₂Te₃/PbTe TEG configurations attain ZTeff = 2.1 at Tm = 550 K, yielding 14.3% conversion efficiency — a 28% improvement over single-stage designs. Modified Betz-Joukowski aerothermodynamic modeling constrains the practical wind turbine efficiency ceiling to 48.7% under realistic atmospheric boundary layer conditions. These findings establish actionable design guidelines and underscore the indispensable role of second-law analysis in next-generation renewable energy optimization. Keywords: Carnot efficiency · entropy generation minimization · solar concentration · thermoelectric generators · Betz limit · exergy analysis · finite-time thermodynamics · renewable energy optimization · LCOE · energy finance

The objective of this work is to present sustainability analysis and performance evaluation of six hydropower units through exergy-based indices. The method of exergy analysis, based on the first and second laws of thermodynamics, was utilized to evaluate system irreversibility and environmental impact. The Exergy Efficiency, Sustainability Efficiency Index (SEI), and Exergy Ecological Index (ECEI) were determined and plotted in MATLAB. The efficiency and exergy performance results show that Unit 6 had the highest exergy efficiency at 89.3%, and Unit 1 had the least at 82.1%. The values of SEI and ECEI showed that elevated exergy efficiency contributes to increasing sustainability and ecological performance in parallel. The results demonstrate that exergy analysis can provide a broader and more accurate measure of system performance than energy analysis in hydroelectric power systems. The approach shows that local reference environmental conditions must be incorporated to establish system equilibrium. It also suggests that exergy analysis should be used as a standard tool for the optimization and performance management of hydropower plants. Its integration would help the operators take measures against malfunction, minimize losses and improve the environmental and thermodynamic sustainability of energy systems.

Innovative multi-objective design of dual-pressure HRSG based on emergy and exergy analysis

Exergy-informed collaborative control of refrigerant-based integrated thermal management systems for electric vehicles

• Calculate the energy dissipation of the intercooler and the recuperator. • Assess the performance of heat exchangers under various flight conditions. • Established the IRTE exergy analysis model. • Compare multiple exergy performance indexes of the IRTE and CCTE. • Evaluate the environmental and sustainability of the IRTE. The intercooled recuperated turbofan engine (IRTE) is a competitive option for the energy-efficient and environmentally friendly aircraft. Nevertheless, the heat transfer capability of the heat exchangers in the IRTE has received limited attention in the research literature. Using entransy dissipation theory, this research has computed and assessed the heat exchange performance of the intercooler and recuperator in the IRTE at various flight altitudes, velocities, and throttling conditions. The calculations reveal that the entransy dissipated in the intercooler and recuperator is small at low altitudes and low Mach numbers, indicating a favorable heat transfer capacity. And the entransy dissipation increases with the percentage rotational speed, and the entransy dissipation is minimum for the design point cruising state. Furthermore, to fill the existing gap in the evaluation of the environmental and sustainability level of the IRTE and its sub-components, this study constructs a comprehensive evaluation framework based on exergy analysis methods, thereby conducting a systematic analysis of the techno-economic, environmental and sustainability of IRTE. And by comparing with the conventional cycle turbofan engine (CCTE), the potential of the intercooled recuperated cycle in enhancing the engine exergy efficiency and reducing fuel exergy flow is revealed from the principle of available energy utilization and transfer, which can play a pivotal role in decreasing adverse environmental risks.

Pressure-boost liquefaction process for low-pressure natural gas: Energy and exergy analysis in small-scale applications

A novel solar tower hybrid multigeneration system for coupled energy and water production: thermodynamic and exergy assessment

Design and performance evaluation of an innovative liquid-cooled battery thermal management system with hexagonal six-flow path channels: Energy and exergy analyses

Multi-objective optimization model to design air-cooled heat exchangers using economic and exergy analyses