Environmental Impact Rate Research Articles

Modeling of a new fuel cell based rail engine system using green fuel blends

Global warming affects climate change and spreads diseases and is of great interest to academic researchers and industry. Transportation significantly contributes to global warming due to the massive carbon emissions because of the dependence on fossil fuels. This paper presents a new rail engine configuration that guarantees lowering carbon emissions and enhancing engine performance. The new rail engine involves a gas turbine that is hybridized with two fuel cells, a solid oxide fuel cell and a proton exchange membrane fuel cell and connected to an energy recovery system. Three analyses are applied to this engine configuration, such as exergy, exergoeconomic, and exergoenvironmental analyses, to provide a comprehensive study of irreversibility, economic and environmental impact aspects. The study results show that the new engine costs $4.8 M, and its levelized rate is 67$/h. Also, its components produce an environmental impact rate of 16 mPt/h, which is negligible. In addition, the overall specific fuel exergy cost and environment are about 34 $/GJ and 12 mPt/h, while the overall specific product exergy cost and environment are about 51 $/GJ and 17 mPt/MJ, respectively. The most economical and least environmental impact were documented by using the mixture of methane and hydrogen because of the low price and least impact of methane compared to other fuels. Finally, the new rail engine is expected to help reduce the environmental impact. It will also be more effective if the most expensive components, such as fuel cells, can be subsidized by government policies.

Mangrove planting initiative within a collaborative project-based biology course to improve students’ climate literacy

Mangrove planting project is one of the most beneficial conservation efforts in coastal areas in terms of environmental impact and carbon sequestration rate. We hypothesized that it would serve as an effective learning strategy if the planting project were planned and organized by the student within a structured biology course. This study examines the impact of the mangrove planting project as a climate initiative program within a biology course towards students’ climate literacy. In this study, 57 students who participated in a mangrove planting project within the Conservation of Coastal Resources course were assigned a climate change questionnaire. The change in participants’ climate literacy was measured before and after the intervention. Climate literacy is measured in three aspects i.e., climate action readiness, climate concerns, and pro-climatic attitude. The result shows that mangrove planting projects increase all measured aspects significantly, with climate action readiness showing the highest improvement. These findings confirmed the benefits of collaborative project-based learning to improve the students’ climate literacy.

Thermodynamics, environmental damage cost, exergoeconomic, life cycle, and exergoenvironmental analyses of a JP-8 fueled turbodiesel aviation engine at take-off phase

The objective of this study is to evaluate the energetic, exergetic, sustainability, economic and environmental performances of a 4-cylinder turbodiesel aviation engine (TdAE) used on unmanned aerial vehicles for the take-off operation mode to assess the system with large aspects. Energy efficiency of the system is found as 43.158%, while exergy efficiency 40.655%. Thermoeconomic analysis gives information about the costs of the inlet and outlet energy and exergy flows of the engine. Hourly levelized total cost flow of the TdAE is found as 21.036 $/h, when the hourly fuel cost flow of the engine is found as 30.328 $/h. The waste exergy cost parameter is determined as 0.0144 MJ/h/$ from exergy cost-energy-mass (EXCEM) analysis, while it is estimated as 14.043 MJ/$ from modified-EXCEM analysis. Environmental damage cost analysis evaluates the cost formation of the exhaust emissions. The total environmental damage cost of the TdAE is computed as 12.895 $/h whilst specific environmental damage cost is determined as 0.054 $/MJ for 494.145 MJ/h TdAE power production. It is assessed that the main contributors to the environmental impact rate of the TdAE are the fuel consumption and the formation pollutants of combustion reaction.

Efficiency, economic and environmental impact assessments of a new integrated rail engine system using hydrogen and other sustainable fuel blends

Locomotives still use antiquated engines, such as internal combustion engines operated by fossil fuels which cause global warming due to their significant emissions. This paper investigates a new hybridized locomotive engine containing a gas turbine system, solid oxide fuel cell system, heat recovery system, and an on-board hydrogen production system. This new integrated engine is operated using five fuel blends composed of alternative fuels, such as hydrogen, methane, methanol, ethanol and dimethyl ether. The current investigation involves multiple studies, such as exergy analysis, exergoeconomic analysis and exergoenvironmental analysis to assess the integrated engine system from three perspectives: efficiency/irreversibility, cost and environmental impact. The present study results show that the net power of this new engine is 4948.6 kW, and it has an exergetic efficiency of 62.7% according to the fuel-product principle. In addition, this engine weighs about 9 tons and costs about $10.2 M, with a levelized cost rate of 147 $/h and 14.06 mPt/h of overall component-related environmental impact rate. The average overall specific fuel and product exergy costs are about 37 $/GJ and 60 $/GJ, and the minimum values are 13.3 $/GJ and 21.8 $/GJ using the methane and hydrogen blend, respectively. Also, the average overall specific fuel-product exergoenvironmental impacts are about 15 and 23 mPt/MJ, respectively. Furthermore, the on-board hydrogen production has an average exergy cost of 274 $/GJ with an environmental impact of 52 mPt/MJ. Moreover, the hydrogen blended with methane or methanol is found to be more economical with less environmental impact.

Optimal design of a novel hybrid solar tower‐gas turbine combined cycle with proton exchange membrane polygeneration system: Application of machine learning

AbstractAn innovative polygeneration system is proposed to generate power, heat, hydrogen, and oxygen simultaneously. The system integrates a solar central tower system and the heliostat field, a gas turbine cycle, a supercritical carbon dioxide cycle, an Organic Rankine Cycle with a cyclopentane working fluid, and a Rankine steam cycle, and a Proton Exchange Membrane electrolyzer. In this study, to reduce the gas cycle fuel consumption, the solar tower system is integrated with the gas cycle. In the studied system, a Supercritical Carbon Dioxide cycle and an Organic Rankine Cycle have been used to heat recovery of the exhaust gases of the gas turbine. In addition, Energy, Exergy, Exergoeconomic, Exergoenvironmental, Emergoeconomic, and Emergoenvironmental analyses have been performed for this system hour by hour. A computer code was developed in MATLAB for these analyses, and the results are validated by simulation in Thermoflex software and primary references with high accuracy. A systematic approach based on thermodynamic analysis and a combination of Genetic Programming and Artificial Neural Networks is proposed for optimal design. Multi‐Objective Genetic Optimization has been employed to find optimum design parameters. Due to the reduction of computation time of optimization, the integration of Genetic Programming and Artificial Neural networks have been employed to generate correlations for objective functions based on the decision variables. By adding the solar system, the mass flow rate of natural gas consumption in the gas cycle decreases by about 9% and reaches 1.53 kg/s. Utilizing solar energy and the Rankine steam cycle, the production capacity of the considered cycle increases from 43 to 66 MW. Also, the performance analysis of the Proton Exchange Membrane electrolyzer and the primary cycle shows that this equipment can produce 0.01 g/s of hydrogen from 5 g/s of water entering the equipment per second by consuming 2.33 kW of power. The results show that when the decision variables are considered at the optimal performance point, the exergy efficiency, the total cost, the rate of destruction related to environmental impacts, cost based on emergy, and the rate of destruction environmental effects based on energy improve. The highest percentage of improvement among the objective functions compared to the initial state is related to the exergy efficiency with 46%, and then the environmental impact rate based on emergy with an improvement of 36%.

Performance assessment and optimization on a novel geothermal combined cooling and power system integrating an absorption power cycle with an absorption-compression hybrid refrigeration cycle in parallel

A novel geothermal combined cooling and power system (CCP) integrating an absorption power cycle (APC) with an absorption-compression hybrid refrigeration cycle (ACRC) in parallel (PAPCRC) is proposed in this paper. Comprehensive energy, exergy, exergoenconomic, and exergoenvironmental analyses on the PAPCRC are conducted, and Multi-objective optimizations are carried out for the PAPCRC and traditional absorption refrigeration cycle (ARC). The results show that the low-temperature vapor generator and evaporator provide the maximum exergy destruction. The highest overall cost rate and overall environmental impact rate belong to the condenser and evaporator. Besides, the system operating under higher high-temperature vapor generator temperature, evaporator temperature and weak solution concentration can provide better overall performance. As well, the optimal outlet pressure of high-temperature vapor generator can be found to maximize net power output and exergy efficiency, and to obtain the best exergoeconomic and exergoenvironmental performance, while the cooling capacity decreases with increasing high-temperature vapor generator outlet pressure. Moreover, compared with the ARC, the PAPCRC obtains significantly better thermodynamic and exergoeconomic performance with an increment in cooling capacity by 89.99% and a reduction in total product unit cost by 43.89%, as well as comparable exergoenvironmental performance with a reduction in total product unit environmental impact by 1.63%.

Exergoeconomic and Exergoenvironmental Analysis of a Novel Power and Cooling Cogeneration System Based on Organic Rankine Cycle and Ejector Refrigeration Cycle

A novel combined power and refrigeration system is proposed based on organic Rankine and jet refrigeration cycles. The system has a wider application range and can be adjusted to different cooling and evaporation temperatures. To meet the needs of diverse populations, the cooling and evaporation temperature can be as low as −60 degrees Celsius. The genetic algorithm is used to optimize the system, and the proposed system’s energy, exergy, economy, and environment are analyzed under optimal conditions. The results desmonstrate that the exergy damage, environmental impact rate, and exergy economic coefficient of steam turbine are the largest. The system’s exergy damage and the turbine’s investment cost are reduced, and the system’s performance is improved. The condenser has the greatest potential for improvement and should be considered a priority component for system improvement. In addition, the system parameters are analyzed. Higher low-pressure steam generation temperature, dryness of low-pressure steam generator outlet, turbine steam extraction ratio, refrigeration evaporation temperature, and compressor compression ratio are advantageous to system cooling capacity output but not the system net power.High-pressure evaporation temperature is unfavorable to the system’s output of net power and cooling capacity. Still, it is beneficial to improve the thermal and energy efficiency of the system. Under the same operating conditions, compared with the system proposed by predecessors, the system’s net power is increased by 12.52 kW, the thermal efficiency is increased by 4.27%, and the energy efficiency is increased by 2.57%. The system was optimized by taking low-pressure evaporation temperature, high-pressure evaporation temperature, outlet dryness of low-pressure steam generator, suction ratio of steam turbine and compression ratio of compressor as decision variables, and thermal efficiency, exergy efficiency, SUCP and SUEP as objective functions. The low-pressure evaporation temperature, high-pressure evaporation temperature, outlet dryness of low-pressure steam generator, suction ratio of steam turbine, and compression ratio of compressor are 357.99 K, 385.72 K, 0.1, and 0, respectively. The system thermal efficiency is 15.01%, exergy efficiency is 43.18%, SUCP is 45.525USD/MWh, and SUEP is 5122.6 MPTS/MWh.

Risk and 4E analyses and optimization of a novel solar-natural gas-driven polygeneration system based on Integration of Gas Turbine–SCO2–ORC-solar PV-PEM electrolyzer

Harnessing combustion gases is paramount to reducing the environmental impacts caused by burning fossil fuels. In this study, an innovative solar-natural gas-driven polygeneration system is proposed for the simultaneous production of power, oxygen, and hydrogen to reduce the environmental impacts of the gas turbine flue gas. The system is composed of a Brayton cycle, supercritical carbon dioxide (SCO2) cycle, organic Rankine cycle (ORC), and a polymer electrolyte membrane (PEM) electrolyzer. An integrated Brayton cycle system is placed on top of this system. In order to recover heat from the exhaust gas of the Brayton cycle, the supercritical carbon dioxide (SCO2) cycle and the organic Rankine cycle (ORC) were used to integrate with this heat source. Also, a polymer electrolyte membrane (PEM) electrolyzer has been used to produce hydrogen and oxygen to increase the ability to produce different materials from this system. In the proposed system, part of the PEM electrolyzer power is provided by solar photovoltaic (PV) collectors to further increase the system's environmental performance. Comprehensive energy, exergy, exergoeconomic, and exergoenvironmental (4 E)-analyses are performed to identify the most significant system performance parameters in terms of thermodynamics, economics, and environment. The proposed system is also examined regarding hazard and risk by two different algorithms. Investigating the probability of occurrence of a hazardous event is done with the method of numerical risk analysis, considering the probability of occurrence of three hazardous incidents with the help of thermodynamic analysis results. Moreover, the integrated polygeneration system is optimized via a multi-objective approach combining genetic algorithm and particle swarm algorithm. The results show that the overall thermal and exergy efficiencies and the total system cost rate are 40.95%, 39.49%, and 7174.36 US$/h, respectively. They also indicated that the total system environmental impact rate is 233.01 Pt/h, while the hydrogen production is equal to 114.83 kg/h. The levelized cost of electricity generation is estimated at 0.056 US$/kWh, and the payback period at 1.4 years. Finally, the performance of six different organic fluids were evaluated and the best one was selected according to the 4 E-analysis of the integrated system. The results of 4 E-analysis reveal that R11 fluid presents the best performance compared to other working fluids. The risk analysis performed with fire and explosion indices shows that the system has a low risk. Numerical risk and risk per exergy unit for the integrated system are estimated at 1.92 × 10−5 injured/year and 5.97 × 10−8 injured/year.kW, respectively.

Performance evaluation and optimization design of integrated energy system based on thermodynamic, exergoeconomic, and exergoenvironmental analyses

With increased cooling load demand and long-term system operation, an existing integrated energy system (IES) has the problems of insufficient cooling capacity, aging of equipment, and high carbon emissions. This paper conducts thermodynamic, exergoeconomic, and exergoenvironmental analyses to evaluate the performance and improvement potential of the system. Then, the advanced exergy analysis is performed to further determine the specific optimization measures. Finally, an optimal IES integrated with parabolic trough collectors, absorption heat pump, and absorption refrigeration is designed. The comparison results show that the natural gas consumption of the optimal IES is reduced by 22.53% while the cold output is improved by 50%, and the system energy efficiency and the system exergy efficiency are increased by 12.90% and 1.99%, respectively. Meanwhile, the total cost rate and the total environmental impact rate of the system are decreased by 26.25% and 35.87%, respectively. Furthermore, the parameter study is carried out to evaluate the effects of various parameters on the performance of the optimal IES. The research could provide theoretical and practical application guidance for performance evaluation and transformation optimization of the IES.

Environmental impact assessments of different auxiliary power units used for commercial aircraft by using global warming potential approach.

In this paper, environmental impact analysis is applied to the various auxiliary power units (APUs) used for commercial aircraft in air transportation sector. The exhaust emissions of different auxiliary power units used in commercial aircraft are investigated. The emission index (EI), global warming potential (GWP) rate, global warming potential index (GWPI), environmental impact (EnI) rate, environmental impact index (EnII), environmental damage cost (EDC) rate, and environmental damage cost index (EDCI) of the exhaust emissions of APUs are computed. The GTCP36-300 model APU has the lowest total emission rate (TER) with 1.333kg/h, the GTC85-129 model APU has the maximum total environmental index (TEI) by 24.719g/kg-fuel, the GTCP36-300 model APU has the best total global warming potential value with 2709.176kg/h CO2_eqv, the TSCP700 model APU has the worst global warming potential index rate as 52.481kg/kWh CO2_eqv, the best total environmental damage cost rate is calculated to be 3.717 €/h for GTC85-72 model APU, the TSCP700 model APU has the highest environmental damage cost index with 0.130 €/kWh, the maximum total environmental impact is computed to be 5656.378 mPts/h for GTCP660 model APU, and the best total environmental impact index is determined for the GTC85-72 model APU.

Life cycle assessment and exergoenvironmental analyses for making a decision in the fuel selection for aero-engines: An application for a medium-size turboprop engine (m-TPE)

Alternative and clean fuel usages are recognized as a crucial step in making air transportation environmentally-benign, efficient and sustainable. Conventional kerosene based jet fuel is mainly used in aviation sector and biofuel is selected as alternative and clean fuel for this investigation. This paper presents the exergoenvironmental analysis of a medium-size turboprop engine (m-TPE) fuelled by jet and biofuel for maximum operation mode (take-off) based on exergy and life cycle assessment (LCA) methodology. Environmental impact regarding the m-TPE and its subsystems is computed using Eco-indicator points per unit hour (mPts/h). Although the component-related environmental impact rate (29.235 mPts/h) of m-TPE is constant for jet and bio fuel utilization, the fuel consumption increases and the exergoenvironmental impact rate reduces by biofuel utilization. Besides, biofuel utilization decreases specific environmental impact of engine product from 5224.91 mPts/GJ to 1384.81 mPts/GJ due to the environmental impact points of fuel lessens from 240 mPts/kg for jet fuel to 55.80 mPts/GJ for biofuel. The results indicate that environmentally-friendly and clean fuel utilization in aero engines goes down environmental impacts although fuel consumption rises up to meet the energy needs of m-TPE. It is expected that the exergoenvironmental analysis method could help comparing m-TPE engines and different fuel utilization in terms of exergy based environmental impact. Additionally, this method can also be effective in making decisions about fuel selection of aero engines.

Exergetic, exergoeconomic, and exergoenvironmental analyses of an existing industrial olefin plant

Light olefins production via thermal cracking of hydrocarbons is a process with the highest value of energy consumption in the petrochemical industry. Therefore, the study of the process from three points of view, i.e., thermodynamic, economic, and environmental, is of interest. In the previous exergy-based analyses of the olefin process, analysis of the steam system along with the other sections is ignored. In this work, for the first time, exergetic, exergoeconomic, and exergoenvironmental analyses of an existing industrial olefin plant with ethane feedstock, at both design and working conditions, are performed. The environmental impacts are calculated through Life Cycle Assessment (LCA). The formation of cost and environmental impact in the plant are indicated through Sankey diagrams. The results indicated that the cracking section (66%), steam system (14%), and ethylene purification section (8%), respectively, are the main contributors to the total exergy destruction. It was illustrated through exergoeconomic analysis that the monetary cost of a product can be very lower/higher than its real exergy-based value. The optimization of the process aiming at the minimum specific total cost rate, the minimum specific total environmental impact rate, or a combination of them per unit of mass of useful products is suggested.

Exergy, exergoeconomic, life cycle, and exergoenvironmental assessments for an engine fueled by diesel–ethanol blends with aluminum oxide and titanium dioxide additive nanoparticles

This study develops energy, exergy, exergoeconomic, exergoenvironmental, and sustainability analyses for a compression ignition (CI) engine fueled with neat diesel (D100), 90 vol% neat diesel + 10 vol% ethanol (D90E10), D90E10 + 100 ppm Al2O3 nanoparticle (D90E10Al2O3), and D90E10 + 100 ppm TiO2 nanoparticle (D90E10TiO2). The experiments were performed on various engine loads (from 3 Nm to 12 Nm with 3 Nm increments) at a fixed crankshaft speed of 2400 rpm. D90E10Al2O3 showed the best energy, exergy, exergoenvironmental, and sustainability results among all fuels. However, according to exergoeconomic analysis, the lowest cost of crankshaft work was obtained with D100, followed by D90E10Al2O3. This means that D90E10Al2O3 presented better exergoeconomic results than its base fuel D90E10 and D90E10TiO2 but worse exergoeconomic results than D100. The addition of ethanol to D100 excessively increased the fuel cost. As a result, the crankshaft work cost flow rate is 0.7645 $/h for D100, 1.1123 $/h for D90E10, 1.1069 $/h for D90E10Al2O3 and 1.1338 $/h for D90E10TiO2. Similarly, the environmental impact rate of work is 250.8 mPt/h for D100, 264.2 mPt/h for D90E10, 245.6 mPt/h for D90E10Al2O3 and 248.7 mPt/h for D90E10TiO2. Increments in the engine load have led to increases in all environmental impact rates due to higher fuel consumption but caused a decrease in the environmental impact rate per exergy unit. In conclusion, it is well noticed that fuel blends with nanoparticles can be used as alternative fuels to their base fuels, but D100 (or an equivalent lower-cost fuel than D100) should be selected for cost-effectiveness purposes.

Energy, exergy, exergoeconomic and exergoenvironmental analysis on a novel parallel double-effect absorption power cycle driven by the geothermal resource

This paper proposes a novel parallel double-effect absorption power cycle using lithium bromide-water solution to make better use of the geothermal source. The comprehensive energy, exergy, exergoeconomic and exergoenvironmental models of this system are developed, and the comparative studies on the thermodynamic, exergoeconomic and exergoenvironmental performance of this system and the traditional absorption power cycle are conducted to reveal the superiority of this system. Besides, the parametric analysis of this system from the exergetic, exergoeconomic and exergoenvironmental viewpoints are performed to determine the effect of the decision parameters on the system performance. The results show that the proposed system driven by geothermal resource can enhance the net power output by 41.3% as well as the exergy efficiency by 12.31% and meanwhile reduce the total product unit cost by 10.12% with slight increase of 1.99% in the total product unit environment impact, compared with the traditional absorption power cycle. In addition, the absorber and the low-temperature generator provide the highest exergy destruction and loss rate with the lowest device exergy efficiency. Moreover, both the highest overall cost rate and the maximum overall environmental impact rate belong to the absorber, followed by the high-temperature turbine. Besides, the operation conditions of this system can be rectified by searching optimal high-temperature turbine inlet pressure or enhancing the high-temperature turbine inlet temperature and the pressure ratio as well as the low-temperature turbine inlet temperature or reducing the absorber outlet temperature and the lithium bromide mass fraction to improve the energy, exergy, exergoeconomic and exergoenvironmental performance of the proposed system.

Life cycle assessment based exergoenvironmental analysis of a cogeneration system used for ceramic factories

In this study, the life cycle assessment based exergoenvironmental analyses are performed to the air compressor (AC), combustion chamber (CC), gas turbine (GT), wall tile dryer (WD), ground tile dryer (GD) and hot air pipeline (PL) included cogeneration system (COGEN) used for ceramic tile factories. Five different environment temperatures are considered for the assessment. Firstly, fuel-product based exergy analysis is performed to the system, and environmental impact parameters are assigned to the exergetic values. The environmental impact rates are found high due to irreversibility rate and low exergy efficiency, especially in the components such as CC (106503.793 mPts/GJ at 30 °C), WD (51914.721 mPts/GJ at 30 °C) and GD (62771.217 mPts/GJ at 30 °C) where chemical combustion reactions occur. Depending on the exergy destruction rate, the relative differences of environmental impact rates in these components are found to be quite higher than other components. The exergy efficiencies of WD (17.430 % at 30 °C) and GD (23.131 % at 30 °C) are lower than other components, and the maximum average specific environmental impacts of fuel are calculated for these components which are calculated as 5549.409 mPts/GJ and 5106.257 mPts/GJ at 30 °C, respectively.

Life Cycle and Exergoenvironmental Analyses of Ethanol: Performance of a Flex-Fuel Spark-Ignition Engine at Wide-Open Throttle Conditions

The growth in the number of vehicles circulating has led to a proportional increase in polluting gas emissions. Bioenergy can be used to help meet these increasing energy demands and mitigate environmental impacts. This work verified the effect of the content of ethanol on the exergy and exergoenvironmental analyses of a spark-ignition engine. Different gasoline–ethanol mixtures were tested along with hydrous ethanol (4.6% water by volume). The thermodynamic data refer to wide-open throttle conditions and variable engine speeds. The life cycle assessment methodology quantified the environmental impacts associated with equipment and fuel using the Eco-indicator 99 method. Pollutants emitted during combustion were measured and included in the environmental assessment (nitrogen oxides, carbon monoxide, and dioxide). Hydrous ethanol at 1500 rpm presented the highest energy efficiency. The effects of the environmental impact rate of pollutant formation and exergy efficiency were significantly higher than the environmental impact rate of fuel. The lowest specific environmental impact of the product (brake power) was 24.39 mPt/MJ, obtained with the fuel blend with 50% ethanol at 2500 rpm. The combined evaluation of the exergoenvironmental factor and the relative difference in environmental impact indicated the optimization priorities and where improvements should be directed.

Comparison of the Environmental Impact and Production Cost Rates of Aggregates Produced from Stream Deposits and Crushed Rock Quarries (Boğaçay Basin/Antalya/Turkey)

Comparison of the Environmental Impact and Production Cost Rates of Aggregates Produced from Stream Deposits and Crushed Rock Quarries (Boğaçay Basin/Antalya/Turkey)

Exergy, Exergoeconomic, Exergoenvironmental, Emergy-based Assessment and Advanced Exergy-based Analysis of an Integrated Solar Combined Cycle Power Plant

The high amount of solar energy as clean and sustainable energy has increased awareness in solar energy concentration, especially in integrated concepts. One of the best and promising hybrid configurations for converting solar energy into power is an integrated solar combined cycle system (ISCCS). In this study, conventional and advanced analysis tools for the ISCCS located in Yazd (Iran) have been investigated. In this paper, thermodynamic simulation, exergy, exergoeconomic, and exergoenvironmental analysis based on Life Cycle Assessment (LCA) have been performed. In addition, an emergy-based concept, including emergoeconomic and emergoenvironmental assessment, has been performed. In-depth analysis of exergy, exergoeconomic, and exergoenvironmental modelling, advanced exergy analysis based on endogenous/exogenous and avoidable/unavoidable parts have been done. In this regard, MATLAB code has been developed for thermodynamic simulation, exergy, exergoeconomic, exergoenvironment, emergoeconomic and emergoenvironment analysis. Furthermore, THERMOFLEX (commercial software) applied for thermodynamic simulation and verification. The Sankey diagram based on each analysis tool has been constructed. Furthermore, the priority of improvement based on each analysis has been identified. The thermal efficiency and net power generation of ISCCS are 48.25% and 419600 kW, respectively. It was obsereved that in most equipment, less than 10% of exergy destruction and cost and environmental impact rates were avoidable/endogenous.

Advanced Exergy, Exergoeconomic, and Exergoenvironmental Analyses of Integrated Solar-Assisted Gasification Cycle for Producing Power and Steam from Heavy Refinery Fuels

Integrated solar-assisted gasification cycles (ISGC) have emerged as a more flexible and environmentally friendly solution for producing power, steam, and other high-valued by-products from low-cost opportunity fuels. In this light, this paper investigates a new ISGC system for converting heavy refineries fuels into power and steam utilities while enhancing energy efficiency and economic and environmental performance indicators. In this approach, a solar energy field and a two-pressure heat recovery steam generator were integrated into the ISGC system to improve overall economic and environmental plant viability. The ISGC system was modelled in MATLAB software, and the results were validated using Thermoflex software. Conventional and advanced energy, exergy, exergoeconomic, and exergoenvironmental (4E) analyses were implemented to assess the main performance parameters and identify potential system improvements. The ISGC system produced 319.92 MW of power by feeding on 15.5 kg/s of heavy refinery fuel, with a thermal efficiency of 50% and exergy efficiency of 54%. The results also revealed an investment cost of $466 million, evaluated at a system cost rate of 446 $/min and an environmental impact rate of 72,796 pts/min. The conventional and advanced 4E analyses unveiled the process economic and environmental feasibilities, particularly for oil-rich countries with high availability of solar resources.

Research on a Solar Hybrid Trigeneration System Based on Exergy and Exergoenvironmental Assessments

The environmental performance of a combined cooling, heating, and power system is analyzed in this study at a component-level using a SPECO-based exergoenvironmental analysis. The engine consumes natural gas and produces 168.6 kW net power. The waste heat is recovered by a LiBr-H2O absorption chiller and a heat exchanger, which are used for cooling and heating purposes. The energy system is assisted by a solar field. An environmental Life Cycle Assessment quantifies the environmental impacts of the system, and these data are combined with exergy evaluations. The highest total environmental impact rate, 23,740.16 mPt/h, is related to the internal combustion engine, of which pollutant formation is the primary source of environmental impact. Compared with a non-renewable energy system, the solar-assisted trigeneration system decreased the environmental impact per exergy unit of chilled water by 10.99%. Exergoenvironmental performance can be further improved by enhancing the exergy efficiency of the solution pump and high-pressure generator (HG), and by employing a treatment to remove nitrogen oxides in the reciprocating engine.