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Qualtra, an innovative 10 MW geothermal power plant proposal, employs a closed-loop design to mitigate emissions, ensuring no direct release into the atmosphere. A thorough assessment utilizing energy and exergy analysis, life cycle assessment (LCA), exergo-economic analysis, and exergo environmental analysis (EevA) was conducted. The LCA results, utilizing the ReCiPe 2016 midpoint methodology, encompass all the spectrum of environmental indicators provided. The technology implemented makes it possible to avoid direct atmospheric emissions from the Qualtra plant, so the environmental impact is mainly due to indirect emissions over the life cycle. The result obtained for the global warming potential indicator is about 6.6 g CO2 eq/kWh, notably lower compared to other conventional systems. Contribution analysis reveals that the construction phase dominates, accounting for over 90% of the impact for almost all LCA midpoint categories, excluding stratospheric ozone depletion, which is dominated by the impact from the operation and maintenance phase, at about 87%. Endpoint indicators were assessed to estimate the single score value using normalization and weighting at the component level. The resulting single score is then used in an Exergo-Environmental Analysis (EEvA), highlighting the well system as the most impactful contributor, constituting approximately 45% of the total impact. Other substantial contributions to the environmental impact include the condenser (21%), the turbine (17%), and the HEGeo (14%). The exergo-economic analysis assesses cost distribution across major plant components, projecting an electricity cost of about 9.4 c€/kWh. [ABSTRACT FROM AUTHOR]

This study investigates the exergetic and exergoeconomic analyses of a diesel engine operated on dual-fuel mode with fuelled both diesel fuel–boron nitride nanofuel and biogas purchased commercially. The experiments were performed for diesel fuel, diesel + 100 ppm boron nitride nanoparticle, diesel + 100 ppm boron nitride nanoparticle + 0.5 L min−1 biogas, diesel + 100 ppm boron nitride nanoparticle + 1.0 L min−1 biogas and diesel + 100 ppm boron nitride nanoparticle + 2.0 L min−1 biogas at various engine loads (2.5 Nm, 5.0 Nm, 7.5 Nm, and 10.0 Nm) and fixed crankshaft speed of 1500 rpm. The obtained experimental data were used to realize exergetic and exergoeconomic analyses. Among the fuels considered in this study, diesel + 100 ppm boron nitride nanoparticle nanofuel had the best exergetic and exergoeconomic results. As a result, at engine load of 10 Nm, the exergy efficiency of test engine and specific exergy cost of crankshaft work were obtained to be 29.12% and 124.86 US$ GJ−1 for diesel + 100 ppm boron nitride nanoparticle nanofuel, respectively. These values were 27.35% and 125.19 US$ GJ−1 for diesel fuel, 25.50% and 141.92 US$ GJ−1 for diesel + 100 ppm boron nitride nanoparticle + 0.5 L min−1 biogas, 23.10% and 156.33 US$ GJ−1 for diesel + 100 ppm boron nitride nanoparticle + 1.0 L min−1 biogas, and 21.09% and 171.92 US$ GJ−1 for diesel + 100 ppm boron nitride nanoparticle + 2.0 L min−1 biogas, respectively. It is clear that biogas addition to combustion made worse the exergetic and exergoeconomic performances of test engine. As a conclusion, it can be said that diesel + 100 ppm boron nitride nanoparticle nanofuel can be used as alternative fuel to D100 in terms of exergy and exergoeconomics. [ABSTRACT FROM AUTHOR]

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This research evaluated the performance of components and sections involved in industrial beer production using exergetic and exergoeconomics methodologies. The system was segmented into five production sections, and three energy input types were considered. The exergetic studies showed an operational exergetic efficiency of 3.33%, with an overall exergetic destruction rate of 5.54 MW and a specific destruction rate of 9.72 kW/hl for beer production. The overall improvement potential and sustainability index were estimated at 4.98 MW and 1.03, respectively. The brewhouse and packaging hall were identified as the sections with the highest production inefficiency, 58.73% and 30.40%, respectively. The exergoeconomic studies revealed a cost rate of 0.1704 USD/s for beer production, with the wort kettle, filling and cocking machine, Kieselguhr candle filter, whirlpool, and brite beer tank identified as the top five significant components in descending order. The efficiency of the system was critically affected by the activities in the packaging hall, particularly those involving energy inputs that cannot be recovered or attributed to the processed stream, beer. Further research is required to determine the cost savings of optimization measures identified from additional steam throttling, downsizing of some main pumps, and exergy loss during heating of wort and beer chilling processes.

The cogeneration system described in this paper is constructed based on a solar-assisted double-effect absorption cogeneration cycle with an adjustable cooling-to-power ratio. As a proposed technique to benefit from the ability to adjust the cooling-to-power ratio, this system is integrated with a cold thermal energy storage system. The procedure described here will be applied to a combined cooling and power system with a thermal energy storage capability for a large medical center in Jeddah, Saudi Arabia. Through an exergoeconomic analysis of the integrated system on a typical summer day in Jeddah, we found that the integrated system could fulfill the cooling and power demands of the medical center under study with an exergetic efficiency of 53.97%. From an economics perspective, the integrated system was found to deliver cooling and power with average unit costs of 222.89 $/GJ and 17.06 $/GJ, respectively. These costs were found to be lower than the unit costs of the respective cooling and power costs delivered to the medical center if they were obtained from an electrically-driven vapor compression system and the electric grid, respectively. For the case study investigated, it has been found that using the integrated system is a desirable approach due to the system's lower unit costs as well as its relatively short payback period. Additionally, it has been found that although cogeneration systems constructed based on the double-effect combined cooling and power cycle have higher exergy destruction and capital investment rates, they have a lower unit cost for the produced exergy in comparison with those of cogeneration systems constructed based on a single-effect combined cooling and power cycle. [ABSTRACT FROM AUTHOR]

Spray drying is a widely used technique for production of milk powder. This is a high level energy consumption process. There are scanty published studies on single-stage spray drying plant for skim milk powder production. In this study, thermodynamic analyses, i.e., energy and exergy analyses and exergoeconomic analysis of single stage spray drying unit has been executed for skim milk powder production. The analyzed parameters are specific exergy destruction ratio, exergy efficiency, relative irreversibility factor, energy improvement potential, exergy improvement potential, specific energy destruction ratio, energy efficiency, and relative energy destruction ratio. The energy and exergy equations were used for computation of these parameters. The energy efficiency and exergy efficiency of plant were computed as 89.63 and 49.19%, respectively. The energy and exergy improvement potential were maximum for drying chamber followed by booster pump, which indicated that there was vast scope in the technical improvement for drying chamber. Highest cost of processing was obtained for drying chamber (percentage relative cost difference: 59.84%) followed by cyclone separator (percentage relative cost difference: 48.98%). Based on these analyses, improvement of high improvement potential components of the spray drying plant may be carried out. [ABSTRACT FROM AUTHOR]

Heat exchangers play a crucial role in industrial processes by facilitating the efficient transfer of thermal energy. The thermophysical properties of nanofluids, which consist of nanoparticles dispersed in conventional heat transfer fluids, are enhanced. Their remarkable thermal conductivity and convective heat transfer characteristics have the potential to significantly improve heat transfer processes. In the present investigation, a numerical study has been carried out to investigate the effect of different nanofluids on heat transfer from outer surface of a spiral coil based on the first and second laws of thermodynamics. The numerical solutions are checked against previous experimental and numerical research in the field. Nusselt number, Euler number, exergy efficiency, irreversibility, and equipment cost are studied with respect to concentration, mass flow ratio (Rm), and shell and tube inlet temperature for a variety of nanofluids, including Al2O3/H2O, CuO/H2O, Fe2O3/H2O, and TiO2/H2O. Compared to water, the exergy efficiency is lower while using nanofluids, as shown by the results, especially in higher nanofluid concentrations, and among the different nanofluids, Al2O3–H2O nanofluid was found to have the highest thermodynamics second law efficiency. The exergy destruction rate experiences linear growth by increasing the nanofluid concentration. A higher pressure drop based on the Euler number is expected for nanofluids. In addition, the consumption of nanofluids on the shell side results in a considerable reduction of the purchased equipment cost (PEC) value compared to water. As opposed to the tube-side input temperature, variations in the shell-side inlet temperature found to have a greater impact on the heat exchanger's exergetic performance.

As a nuclear power source, gas turbine modular helium reactors (GT-MHR) can play a major role in the energy industry due to their high safety index and low operating costs. In light of the GT-MHR's high heat capacity, this study integrates a GT-MHR cycle with a Stirling engine to achieve a high-efficiency electricity production framework in an eco-friendly framework. Multi-aspect study from energy, exergy, economic and exergoenvironmental viewpoints are conducted. Detailed heat exchanger modeling is performed to accurately evaluate the system's performance conditions as part of the design process. The outcomes of this study reveal that in the optimum operating mode, the turbine's inlet temperature and expansion ratio are 1300 K and 2, respectively. The compressor compression ratio is 2.1, the Stirling engine inlet temperature is 850.6 K, and the regenerative effectiveness is 0.866. Consequently, the system's total electricity becomes 325.57 MW with 54.26 % energetic and 75.13 % exergetic efficiencies. The economic assessment of the system reveals that the unit electricity product cost is 8.9 $/GJ, and the total investment cost is 12737 $/h. Also, the optimal exergoenvironmental results show an exergoenvironmental index of 0.237, an environmental damage effectiveness index of 0.0031, and an exergetic stability factor of 0.24. Compared to GT-MHR, GT-MHR/KC, GT-MHR/APC, and GT-MHR/ORC, the newly designed system produces 44.57, 21.47, 29.74, and 25.17 MW more electricity and is more energetically efficient by 28.3 %, 24.45 %, 25.8 %, and 25.07 %, respectively.

This paper presents an in-depth investigation into the performance of Mashhad Tous power plant in Iran, a natural-gas-fueled steam cycle with an output power of 4 × 150 MW. The analyses include energy, exergy, and exergoeconomic. To facilitate the study, a robust code is developed to simulate the thermodynamic topology of the power plant. The fidelity of the simulation is validated using realistic site conditions. The study incorporates three vital decision variables: boiler water mass flow rate, turbine inlet pressure from, and ambient temperature ranging from 90 kg ⋅ s − 1 to 150 kg ⋅ s − 1 , 12 MPa to 19 MPa, and 10 °C to 40 °C, respectively. Three different heat loads, including 423 MW, 311 MW, and 214 MW, are used to analyze the performance of the power plant. A Pareto-based multi-criteria optimization intertwined with the technique for order of preference by similarity to the ideal solution (TOPSIS) is used to find the optimum conditions in terms of having the highest work output and exergy efficiency while simultaneously reducing the plant's total cost. The optimization results demonstrate a 4.28% increase in output at full load (423 MW). Additionally, a 1.52% increase is observed at partial load (311 MW), and there is a notable 16% increase in output at low load (214 MW). These improvements also positively impacted energy efficiency. Specifically, there is a 4% improvement at full load, a 0.9% enhancement at partial load, and a remarkable 5.4% increase in energy efficiency at low load. In terms of costs, substantial reductions of 37% at full load, 31% at partial load, and an impressive 72% at low load are evident. [ABSTRACT FROM AUTHOR]

In this study, the exergy, exergoeconomic, enviroeconomic, and sustainability index analyzes of blends of biodiesel and diesel obtained from waste animal fats were examined. Within the scope of this study, the engine used in the experimental study has the features of a 3000-rpm fixed-speed four-stroke, single-cylinder, and air-cooled compression ignition engine. In addition, seven different fuels (D100 (0% Biodiesel + 100% Diesel), D90B10 (90% Diesel + 10% Animal Biodiesel), D80B20 (80% Diesel + 20% Animal Biodiesel), D70B30 (70% Diesel + 30% Animal Biodiesel), D50B50 (50% Diesel + 50% Animal Biodiesel), D25B75 (25% Diesel + 75% Animal Biodiesel), B100 (0% Diesel + 100% Animal Biodiesel)) were used in this study. The experiments were performed by loading the engine at 500 W intervals between 500 and 3000 W. As a result, the highest exergy efficiency was 24.86%, and obtained in D90B10 fuel at a 3000 W engine load. The lowest relative cost difference was 2.04, and obtained in D90B10 fuel at 3000 W engine load. The maximum sustainability index value was 1.98, and obtained in D90B10 fuel at a 3000 W engine load. In terms of enviroeconomics, while the cost of annual CO2 emission of all fuels is low at low engine loads, it increases as engine load increases. It is seen that D90B10 fuel is closest to D100 fuel at low engine loads. Their values are respectively 42.55 USD year−1 and 43.22 USD year−1. [ABSTRACT FROM AUTHOR]

Cogeneration and trigeneration systems have been broadly employed as part of the strategies oriented toward rational energy use. The assessment of these systems must include simultaneous considerations of costs, irreversibility, energy losses, and their causes. This work presents a step-by-step thermoeconomic analysis of a microcogeneration unit, composed of an internal combustion engine and an NH3-water single-effect absorption refrigeration chiller. The research employed the Theory of Exergetic Cost method to determine monetary and energy costs and the exergy efficiency of equipment. It is therefore, possible to identify which pieces of equipment present the highest impact and focus on these to improve the overall performance of the energy system. Although not part of the Theory of Exergetic cost, exergoeconomic parameters can be calculated to expand the assessment further. The highest specific exergy cost is associated with the endothermic reaction inside the absorber (282 $/GJ), while the lowest specific exergy cost is due to electricity consumed by the pump of the refrigeration system (2.16 $/GJ). The highest exergy efficiency was identified at the condenser (almost 90%, while values under 40% were obtained for the engine, pump, and absorber. The combined analysis of exergoeconomic results indicates that the lowest performances are related to the generator, the absorber, the evaporator, and the regenerator. [ABSTRACT FROM AUTHOR]

The present work highlights the exergoeconomic analysis of photovoltaic (PV) systems. It consists in carrying out an exergy and economic balance of these systems to evaluate the energy losses at all levels of the production chain. For this purpose, a 11,52 kWp power plant with storage installed at Maroua Airport (tropical dry region) and a 1,25 MWp grid connect plant at Douala Airport (tropical humid region) are considered. The meteorological data and the cells' temperature which highly affect the PV performances are directly measured on site. The estimated useful exergy production of electricity is about 1585.68 kWh/kWp/yr in Maroua PV plant and 1452.75 kWh/yr in Douala PV plant. The losses are respectively evaluated to be 142.76 kWh/kWp/yr in Maroua and 37.6 kWh/kWp/yr in Douala. The performance of each plan is evaluated using the exergy matrix concept. The results obtained give an exergy payback time value of 6.19 years for the Maroua plant, which is higher than the exergy return time of the Douala plant, which is 5.25 years due to losses related to storage system, the cost per kilowatt-hour of useful electrical energy produced is 0.130 UDS for the Maroua plant and 0.002 USD for the Douala plant. The cost of exergy losses per kWp/yr is estimated at 19.163 USD for the Maroua plant, and 0.065 USD for the Douala plant. Thus, the exergy losses are higher for solar PV systems installed in the Sahelian regions of the country, and even higher for systems with storage. Based on this analysis, it appears that the PV plant installed in the dry tropical zone is more efficient, while the one installed in the humid tropical zone has a better production cost. Fortunately, these climatic regions are favorable for the implementation of PV plants.

An analysis of review articles on solar drying of agricultural products is presented. The review also discusses detailed economic evaluation methods and market participation approaches for transitioning solar dryers from the workshop to the market. This study aims to serve as a model for future solar drying reviews. In addition to broad perspective reviews, most reviews focused on using thermal storage, hybrid technologies, solar greenhouses, 4E evaluations, software applications and crop quality. From most of the reviews, solar dryers with thermal storage are now a viable substitute for fossil energy source dryers and can provide the continuous temperature range of 40–60 °C required to dry food crops. When phase change material is deployed, the transition temperature should be at 5 °C above the desired drying temperature. However, all reviews included sections on types, classification, mode of airflow through the collector, and use of thermal storage in solar drying. Hence, the authors review nearly the same research material, but review gaps remain. Thus that aspect was covered by examining the economic and exergoeconomic analysis methods used in solar dryer evaluations. Again agribusiness inter-phasing between researchers and users, which will spore market participation of solar dryer fabricators lacking in the literature were presented. Therefore, for a more market-oriented development of solar thermal technologies, solar dryer producers must engage in market-oriented production. The nature of markets located at different places calls for better strategies to improve market orientation and access to solar dryers and fabricators.

In this study, ten different blends were prepared with binary and ternary combinations of diesel, palm oil biodiesel (0 vol%, 15 vol%, 20 vol% and 30 vol%), and diethyl ether (0 vol%, 5 vol% and 10 vol%) and were tested in a diesel engine. The experiments were performed on various engine loads (500 W, 750 W, 1000 W and 1250 W) and various injection timings (25° CA bTDC, 30° CA bTDC and 35° CA bTDC) at a fixed crankshaft speed of 3000 rpm. The prepared blends were compared in terms of exergy and exergoeconomics. It may be said that exergy efficiency and specific exergy cost of work for blends improved with increasing injection timings at high engine loads. However, at low engine loads, these parameters worsened with increasing injection timings. As a result, at 500 W, relative exergy efficiency of D70PO20DE10 was 0.57 for 25° CA bTDC and 0.54 for 35° CA bTDC. However, at 1250 W, this value was 0.59 for 25° CA bTDC and 1.16 for 35° CA bTDC. Similarly, at 500 W, relative specific exergy cost of work for D70PO20DE10 was 5.29 for 25° CA bTDC and 5.94 for 35° CA bTDC. However, at 1250 W, this value was 5.31 for 25° CA bTDC and 2.66 for 35° CA bTDC. Finally, it can be concluded that neat diesel had the best results compared to all blends considered in this study in terms of exergy and exergoeconomics. [ABSTRACT FROM AUTHOR]

A heat exchanger was integrated to increase the efficiency of a geothermal double flash cycle and decrease the liquid content at a low-pressure turbine outlet. The liquid cooling (LC) and liquid splitting technologies have three different configurations: i.) steam superheating (SH), ii.) steam reheating (RH) and iii.) mixture heating (MH) was implemented. An exergoeconomic analysis was applied to the systems and analyzed using geothermal power plant operation parameters. An increase in the net power of the double flash cycle of 418.6 kW was achieved with LC-SH configuration, 5008.6 kW with LC-RH, 5248.6 kW with LC-MH, 3758.61 kW with LS-RH and 3958.61 with LS-MH. The power of the low-pressure turbine also increased compared to the double flash design in a 0.5236% (SH), 5.48%(RH), and 5.72%(MH), and the produced electricity cost were 5.9963 $ USD/GJ, 5.9976 $ USD/GJ, 6.0089 $ USD/GJ, 6.0086 $ USD/GJ, 5.9336 $ USD/GJ, 5.9482 $ USD/GJ and 5.9481 $ USD/GJ for the double flash, DF-LC-SH, DF-LC-RH, DF-LC-MH, DF-LS-SH, DF-LS-RH, and DF-LS-MH designs, respectively. The DF-LS-SH design is the most feasible because the cost of electricity produced is reduced while the steam quality of the low-pressure turbine and the net power of the geothermal plant increases. • Six modifications to a double flash cycle were analyzed from an exergoeconomic point of view. • The design of liquid splitting and superheating reduced the exergy cost to 5.9336 $ USD/GJ compared to the double-flash base case. • The liquid cooling technology with mixture heating improved the net power by 5331.61 kW. • The liquid content at the outlet of the low-pressure turbine was reduced by 5.54%. [ABSTRACT FROM AUTHOR]

Exergoeconomics has played an important role in the study of new energy systems in the last decades. The use of exergy as a "carrier of value" has made it possible to define an unambiguous criterion for allocating costs among energy systems products. The paper shows how exergoecomic procedures of analytical optimization and design improvement on heuristic basis have been progressively replaced by more efficient procedures aimed at minimizing an objective cost function, leaving exergoecomic cost evaluation as the final step. It also highlights how growing concerns about climate change and the continued growth of inequalities in energy availability have broadened the set of objectives in the search for the optimal integration of the design and operation of energy conversion units and network with intelligent methodologies to reduce energy demands. The objective of the article is twofold: i) present the evolution of the main Exergoeconomic methods and show how they have paved the way for Thermo-X Optimization methods; and ii) outline the path for developing a general model of society's entire energy system that includes a broader set of objectives and constraints in addition to economic ones to help build the energy system of the future with a more sustainable perspective. • It is shown how Exergoeconomic procedures paved the way to Thermo-X Optimizations. • The paper outlines the path towards a general model of society's entire energy system. • The need to avoid wastes to reduce energy demand in wealthier nations is stressed. [ABSTRACT FROM AUTHOR]

Exergy-based methods consist of at least an exergetic analysis, which can be combined with an economic analysis and a life cycle assessment in order to evaluate and improve energy-intensive processes. The author coined the term exergoeconomics in 1984 to replace the term thermoeconomics when exergy costing is used in the combination of an exergetic analysis with a cost analysis and to emphasize the role of exergy in the efforts to reduce the product cost. He also developed a general exergoeconomic methodology based on exergy-based variables and on appropriate definitions of the "product" and "fuel" for each component of an energy conversion system. These definitions and the application of exergoeconomics were generalized by A. Lazzaretto and the author in 2006 in an approach based on specific costs (SPECO approach). L. Meyer and the author coined the term exergoenvironmental analysis in 2009 for the combination of an exergy analysis with a life-cycle analysis when exergy is used to assign environmental impacts to streams. An exergoenvironmental analysis uses the methodological background of exergoeconomic methods. Starting in 2002, to reduce the limitations of the conventional exergy-based methods, and to facilitate system optimization, the author, and later in cooperation with T. Morosuk and co-workers at TU Berlin, developed the advanced exergy-based methods, which are based on the notion that the inefficiencies (exergy destruction and exergy loss), the costs, and the environmental impacts can be split into avoidable/unavoidable and endogenous/exogenous parts, to improve understanding of the formation process of inefficiencies, costs and environmental impacts within an energy conversion system. As often happens, after their introduction, all the above terms and methods have been misused and misinterpreted by some other authors. This paper briefly reviews past contributions by the author and some other exergy practitioners and discusses future developments. It concludes, that the advanced exergy-based methods need further development to be generalized, and integrated and to reduce their subjectivity in addition to the efforts and time required for their application. Development of appropriate software and shortcut methods will facilitate their use by researchers and engineers in industry and the application of exergy-based methods in energy-intensive industrial processes for multiobjective optimization purposes. • The most promising exergy-based methods are briefly reviewed. • Expected future developments are discussed. • More industrial applications are needed. • Misinterpretations and misuses of the methods limit their development. • The methods can be used to fairly apportion pollutants among countries. [ABSTRACT FROM AUTHOR]

This paper presents an in-depth investigation into the performance of Mashhad Tous power plant in Iran, a natural-gas-fueled steam cycle with an output power of 4 × 150 MW. The analyses include energy, exergy, and exergoeconomic. To facilitate the study, a robust code is developed to simulate the thermodynamic topology of the power plant. The fidelity of the simulation is validated using realistic site conditions. The study incorporates three vital decision variables: boiler water mass flow rate, turbine inlet pressure from, and ambient temperature ranging from 90 kg⋅s−1 to 150 kg⋅s−1, 12 MPa to 19 MPa, and 10 °C to 40 °C, respectively. Three different heat loads, including 423 MW, 311 MW, and 214 MW, are used to analyze the performance of the power plant. A Pareto-based multi-criteria optimization intertwined with the technique for order of preference by similarity to the ideal solution (TOPSIS) is used to find the optimum conditions in terms of having the highest work output and exergy efficiency while simultaneously reducing the plant’s total cost. The optimization results demonstrate a 4.28% increase in output at full load (423 MW). Additionally, a 1.52% increase is observed at partial load (311 MW), and there is a notable 16% increase in output at low load (214 MW). These improvements also positively impacted energy efficiency. Specifically, there is a 4% improvement at full load, a 0.9% enhancement at partial load, and a remarkable 5.4% increase in energy efficiency at low load. In terms of costs, substantial reductions of 37% at full load, 31% at partial load, and an impressive 72% at low load are evident.

The concern for environmental devastation due to high dependency on fossil fuel sources is shifting focus towards efficient utilization of energy by integrating renewable energy and integrated energy system. Efficient energy deployment can be attained by alleviating the actual losses, costs and environmental impact of the energy sources. This paper aims to address the above issues by reviewing the 4E analysis known as energy, exergy, exergoeconomic and exergoenvironment analysis of thermal power plants, intermittent renewable energy and integrated energy system. Amongst other noteworthy aspects outlined in this paper, it has been found out that extensive work has been done on TPP energy and exergy analysis but exergoeconomic and exergoenvironment analysis are still considered as emerging fields. Moreover, most of the analysis conducted for intermittent renewable energy and integrated energy system is based on energy analysis. Some vital conclusions have been drawn from literature survey like boiler, PV surface module and wind rotor are the major sources of exergy destruction/losses in thermal power plants and intermittent renewable energy system. Decreasing the above components losses will significantly increase the energy quality, thereby will achieve a cost-efficient, sustainable and eco-friendly energy system.

The use of the organic Rankine cycle (ORC), organic flash cycle (OFC) and Kalina cycle (KC) is proposed to enhance the electricity generated by a supercritical CO2 recompression Brayton (SCRB) cycle. Novel comparisons of the SCRB/ORC, SCRB/OFC and SCRB/KC integrated plants from thermodynamic, exergoeconomic and sustainability perspectives are performed to choose the most appropriate bottoming cycle for waste heat recovery for the SCRB cycle. For comprehensiveness, the performance of the SCRB/OFC and SCRB/ORC layouts are examined using ten working fluids. The influence of design parameters such as pressure ratio in the supercritical CO2 (S-CO2) cycle, pinch point temperature difference in heater and pre-cooler 1, turbine inlet temperature and pressure ratio for the ORC/OFC/Kalina cycles are examined for the main system indicators including the net output power, energy and exergy efficiencies, and unit cost of power production. The order of the exergy efficiencies for the proposed systems from highest to lowest is: SCRB/ORC, SCRB/OFC and SCRB/KC. The minimum unit cost of power production for the SCRB/ORC system is lower than that for the SCRB/KC and SCRB/OFC systems, by 1.97% and 0.75%, respectively. Additionally, the highest exergy efficiencies for the SCRB/OFC and SCRB/ORC systems are achieved when n-nonane and R134a are employed as working fluids for the OFC and ORC, respectively. According to thermodynamic optimization design, the SCRB/ORC, SCRB/OFC and SCRB/KC systems exhibit sustainability indexes of 3.55, 3.47 and 3.39, respectively. [ABSTRACT FROM AUTHOR]

The use of an internal heat exchanger in vapor compression refrigeration systems of one stage is a common practice because it helps to increase the cooling capacity in the evaporator. Furthermore, the use of refrigerants with low global warming potential is becoming more frequent due to environmental regulations worldwide. Thus, this paper presents an evaluation of the improvement produced by the inclusion of an internal heat exchanger cycle (IHXC) in an experimental installation from the viewpoint of exergy, economic and environmental through to exergy, exergoeconomics, and Specific Life Cycle Climate Performance (SLCCP) studies. The tests were conducted using R1234ze(E) as a replacement alternative to R134a in three evaporating temperature conditions: 4 °C, 9 °C, and 14 °C. Comparisons were made considering R134a in BRC mode versus R1234ze(E) in BRC and IHXC modes. Results show that a lower environmental impact is produced by an evaporating temperature of 14 °C with a reduction in SLCCP of 13.3% using IHXC and R1234ze(E). Moreover, the highest increase in exergy efficiency was observed for an evaporating temperature of 4 °C, with this increase being 9%, while the lowest increase in the total cost rate was observed for the same evaporating temperature, being 12.3% and 21.2% for BRC and IHXC modes using R1234ze(E), respectively. [ABSTRACT FROM AUTHOR]

Thermal grids are efficient, reliable, and sustainable technologies for satisfying the thermal demands of buildings. The capability to operate at a low temperature allows not only for the integration of heat produced by renewable energy sources but also for the storage of surplus electricity from the grid via "power to heat" technologies. Besides, in the future, heat consumers are expected to behave increasingly as "prosumers", supplying in some periods heat produced by renewable energy plants on site. In this scenario, it is important to propose a method for the cost allocation among producers connected to the grid. In this regard, this paper proposes Exergoeconomics as a possible tool for rational cost assignment. To show the capabilities of the method, some operating scenarios are compared for a cluster of five buildings of the tertiary sector interconnected by a thermal grid. Based on exergoeconomic indicators, such as the exergy and exergoeconomic unit costs, insights into the cost formation process of the heat consumed by users are provided. Sensitivity analyses of heat unit cost to design and operating variables are also performed. Results show that in the presence of distributed producers, the heat unit cost could be approximately 33% lower than in the case of centralized production, due to the lower amount of irreversibility generated. Capital investment accounts for 20–28% of the heat unit cost. [ABSTRACT FROM AUTHOR]

Researchers have constantly been looking for renewable alternative fuels due to high fuel price volatility, energy security concerns, and produced harmful emissions. One of the promising alternatives is to produce biodiesel from waste economical feedstock such as chicken fat. Esterification and transesterification are used to create methyl ester from chicken fat. Then, 25%, 50%, 75%, and 100% of chicken oil biodiesel are volumetrically blended with diesel fuel. Diesel engine is loaded between 0% and 100% at 3000 rpm rated speed. Exergetic and exergoeconomic assessments of diesel engine fuelling with blends of chicken biodiesel were conducted in the present study. Diesel oil performed most efficiently in terms of exergy. For B100, the worst exergetic results are attained. The exergy efficiency of test engine at 75% engine load was 33.25% for the D100 and 27.85% for the B100. D100 produced the best exergoeconomic findings, while adding biodiesel to D100 made the exergoeconomic parameters worse. Crankshaft work had a particular exergy cost of 110.02 $/GJ for D100 and 194.37 $/GJ for B100 at 75% of engine output power. In the conclusion, it is noted that the waste chicken fat methyl ester can be used at low fractions as a substitute for traditional diesel fuel without modifying the engine, and this is a promising solution for waste management, turning waste products into an energy source, and dwindling fossil fuel reserves. • Biodiesel was produced with the following of esterification and transesterification methods. • Chicken fat biodiesel blends were tested in terms of exergy and exergoeconomics. • Theory of Exergetic Cost (TEC) was applied to discuss the performance comparison of the test fuels. • Chicken oil biodiesel fuels presented very competitive results in terms of performance indicators. • Exergy costs for crankshaft work for D100 and B100 were 110.02 and 197.37 $/GJ, respectively. [ABSTRACT FROM AUTHOR]

• Introduces preselection approach based on investment and operating costs. • Introduces preselection approach based on exergoeconomics. • TCI and OPEX are equally important to decide on the use of equipment modules. • Preselection based directly on investment and operating costs is most suitable. The idea of module-based plant design is to select equipment modules of-the-peg instead of designing plants completely tailor-made to speed up plant design. Using equipment modules in plant design leads to equipment that does not exactly fit requirements. For some process units of a plant this might result in a moderate increase of investment and/or operating costs; for others using equipment modules of-the-peg might lead to a substantial increase of costs. The key question is: For which process units of a plant can one afford increased costs due to equipment modules not exactly fitting the requirements? In this work the effect of using equipment modules on investment and operating costs is investigated. Three different preselection approaches to decide on the use of equipment modules are applied and evaluated. One is purely based on investment costs, whereas the two other approaches developed consider investment and operating costs, either directly or based on exergoeconomics. Using the fermentative production of succinic acid as case study, it is shown that investment and operating costs are equally important and that the preselection approach based directly on investment and operating costs is found most suitable when deciding on the use of equipment modules. [ABSTRACT FROM AUTHOR]

Summary: In the present study, multi‐objective optimization has been conducted to optimize a novel multigeneration system that is based on biomass energy, and uses the cold energy of the liquid natural gas as a heat sink. The designed system is an integration of combined gas‐steam cycle, a cascade Rankine cycles, a lithium bromide‐water absorption refrigeration cycle, a proton exchange membrane electrolyzer, and a liquid natural gas subsystem. The proposed system aims to produce power, cooling, natural gas, and hydrogen. Following thermodynamic and exergoeconomic analysis, two conflicting objectives, that is, total product cost rate and exergy efficiency, are selected for the optimization process. The genetic algorithm is used to optimize the system and the Pareto front plot is achieved. The obtained results for this system reveal that the final optimization point has an exergy efficiency of 39.023% and a total product cost rate of 1107$/h. This point is a trade‐off between thermodynamic and thermoeconomic single‐objective optimization cases. In addition, the biomass gasification‐gas turbine cycle, organic Rankine cycles, and proton exchange membrane have the highest exergy destruction rates, respectively. Finally, it is shown that the liquid pressure ratio of the natural gas pump and inlet temperature of the steam turbine have the most important effects on the balance between the selected objective parameters. [ABSTRACT FROM AUTHOR]

• A novel direct-fired supercritical CO 2 power cycle (DETRC) is proposed. • DME is DETRC's fuel with a high hydrocarbon ratio and self-oxygenating properties. • Cycle performance analysis takes into account the effects of combustion. • Thermal efficiency increases by 25.45 % and unit product cost decreases by 18.31 %. • 554.1 kW DETRC's net power and 9.29 ¢/kW∙h unit product cost available. A direct-fired supercritical CO 2 power cycle with a novel layout and dimethyl ether (DME) as fuel is proposed, named the dual expansion and triple recuperation cycle (DETRC). To obtain accurate cycle simulation results, the combustion products' state parameters and species concentrations are used as the inputs of cycle simulation, which are obtained from a three-dimensional combustion simulation. The performance of DETRC is compared with those of the direct-fired Allam cycle and other published direct-fired cycles. The effects of the CO 2 recycling ratio, excess oxygen coefficient, in-combustor pressure, and turbine outlet pressure on the thermodynamic and exergoeconomic performance are investigated to obtain the optimal operating variables for DETRC. The results indicate that DETRC has excellent thermodynamic and exergoeconomic performance. Compared to the Allam cycle, the exergy losses of recuperators and coolers are reduced significantly, thermal efficiency is increased by 25.45 %, and the unit product cost is reduced by 18.31 % in the DETRC. Compared to the direct-fired cycles in the literature, the thermal and exergy efficiencies increase, and oxygen consumption reduces. The effect of the CO 2 recycling ratio or excess oxygen coefficient on DETRC is non-monotonic. As the CO 2 recycling ratio or excess oxygen coefficient increases, the thermal and exergy efficiencies increase and then decrease, and the unit product cost decreases and then increases. With in-combustor pressure increasing, the thermal and exergy efficiencies increase, unit product cost decreases, and the cycle performance is improved. As turbine outlet pressure increases, the thermal efficiency increases and then decreases, exergy efficiency increases, and unit product cost decreases and then increases. The optimal operating variables are that the CO 2 recycling ratio is 0.95, the excess oxygen coefficient is 1.20, the in-combustor pressure is less than 30 MPa, and the turbine outlet pressure is 5.5 MPa. [ABSTRACT FROM AUTHOR]

This paper investigates different configurations of organic Rankine flash cycles combined with a Brayton cycle by performing thermodynamic, exergy, and exergoeconomic analyses. The thermal energy of the cycle is produced through burning gaseous methane generated via gasification of biomass. A systematic analysis of these configurations is conducted to enhance the exergy efficiency of the cycles. Additionally, the reutilization of the thermal energy that would otherwise be wasted in the Brayton cycle contributes to a notable enhancement in the overall thermal efficiency of the combined cycle. A range of working fluids, namely m-Xylene, o-Xylene, p-Xylene, toluene, and ethylbenzene are analyzed for the organic Rankine cycle. Predictions using an artificial neural network (radial base function) are also carried out. The results indicate that the p-Xylene increases exergy efficiency more than other working fluids. Further, the improved organic Rankine cycle mitigates exergy destruction by 10 %. Although applying double flash evaporators improves the exergy efficiency by 3 %, it increases the unit cost of power generated by more than 10 %. The application of a data-driven model to predict various configurations of combined organic Rankin cycle with a Brayton cycle fed by biomass has rarely been investigated. • The p-Xylene decreases the exergy destruction, considerably. • The ODFRC contained a higher unit cost of power produced. • In terms of higher investment cost, the cycles are ranked as ODFRC, SOFRC, and IOFRC. • Having higher thermal efficiency, the cycles are ranked as IOFRC, ODFRC, and SOFRC. • The precision of RBF-ANN for predictions of the studied cycles is confirmed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Integrated process for blue and green hydrogen production through co-gasification. • Co-gasification process IRR of 8% at a process efficiency level of 70%. • Exergoeconomics costs of steam turbine and gasifier 6,561.3 $/h and 6,541.9 $/h. • Green hydrogen production through alkaline electrolysis cell (AEC) • Surplus electricity has a potential AEC green hydrogen production of 213.5 kg/day. A novel co-gasification process for biomass and plastic waste has been proposed to produce the blue and green hydrogen. For process feasibility, an Aspen Plus simulation model has been developed, and a sustainability analysis is being conducted, focusing on economic viability, exergy, advanced exergy considerations, and exergoeconomics evaluations. The current process has demonstrated economic sustainability, as evidenced by an internal rate of return (IRR) of 8 % at a process efficiency level of 70 %. The process with a waste capacity of 20 tons per hour has the potential to produce approximately 1079 kW-hours of electric power. The surplus electricity, exceeding the process requirements is utilized for green hydrogen production through an alkaline electrolysis cell (AEC). This surplus electricity has the potential to produce around 213.5 kg/day of hydrogen. The exergy analysis of this model highlights that the gasifier component exhibits the lowest exergy efficiency, resulting in the highest exergy loss, around 40 %. Furthermore, advanced exergy analysis identifies both the steam turbine and gasifier as primary sources of exergy destruction, with associated exergoeconomics costs of around $6,561.3 and $6,541.9 per hour, respectively. Consequently, improving the gasifier and steam turbine performance can enhance the overall sustainability of the process. [ABSTRACT FROM AUTHOR]

In this study, we used the thermoeconomic theory to evaluate the impact of residue cost formation on the cost of electricity generated from natural gas burned in a gas turbine that applied sequential combustion; we also analyzed the impact of the combustion process on the additional fuel consumption to compensate for a malfunction component. We used the Alstom GT24 gas turbine, which applied sequential combustion and generated 235 MW of power. Thermoeconomic analysis indicated that the exergy cost of power generation was 626.33 MW (30.42% corresponded to irreversibility costs, and 29.22% and 2.84% corresponded to the formation costs of physical and chemical residues, respectively). The exergoeconomic production cost of gas turbine was 10,098.71 USD/h, 34.76% from external resources and 65.24% from capital and operating costs. Thermoeconomic diagnosis revealed that a compressor deterioration (of 1-% drop in the isentropic efficiency) resulted in an additional fuel consumption of 4.05 MW to compensate for an increase in irreversibilities (1.97 MW) and residues (2.08 MW); the compressor generated the highest cost (49.9% of additional requirement). Thus, our study can identify the origin of anomalies in a gas-turbine system and explain their effects on the rest of the components.

The present study aimed to investigate a multi-generation energy system for the production of hydrogen, freshwater, electricity, cooling, heating, and hot water. Steam Rankine cycle (SRC), organic Rankine cycle (ORC), absorption chiller, Parabolic trough collectors (PTCs), geothermal well, proton exchange membrane (PEM) electrolyzer, and reverse osmosis (RO) desalination are the main subsystems of the cycle. The amount of exergy destruction is calculated for each component after modeling and thermodynamic analysis. The PTCs, absorption chiller, and PEM electrolyzer had the highest exergy destruction, respectively. According to meteorological data, the system was annually and hourly tested for Dezful City. For instance, it had a production capacity of 13.25 kg/day of hydrogen and 147.42 m3/day of freshwater on 17th September. Five design parameters are considered for multi-objective optimization after investigating objective functions, including cost rate and exergy efficiency. Using a Group method of data handling (GMDH), a mathematical relation is obtained between the input and output of the system. Next, a multi-objective optimization algorithm, a non-dominated sorting genetic algorithm (NSGA-II), was used to optimize the relations. A Pareto frontier with a set of optimal points is obtained after the optimization. In the Pareto frontier, the best point is selected by the decision criterion of TOPSIS. At the TOPSIS point, the exergy efficiency is 31.66%, and the total unit cost rate is 21.9 $/GJ. • ANN modeling tool was implemented on the multi-generation system. • The exergy efficiency at the TOPSIS point is 31.66%. • A novel multi-generation system based on solar and geothermal is presented. • The PEM electrolyzer and the RO utilized to produce hydrogen and freshwater. [ABSTRACT FROM AUTHOR]

Exergoeconomic analysis is a tool used to identify hidden costs associated with a machine or a system that cannot be identified using typical cost management techniques applied in the industry. While exergoeconomic analysis finds applications in power system innovations and optimization, it has not yet been harnessed by the manufacturing industry to reduce operating costs. The purpose of this study is to use exergoeconomic analysis to identify hidden costs in manufacturing processes, with a focus on the industrial beverage mixer system. The study proposes a methodology of identifying the hidden financial losses in the system and recommends modifying the systems operation and design as a measure to reduce costs and increase profitability. Thermodynamic and economic data for the study were obtained from manufacturing plants. An exergy cost analysis was performed using thermoeconomic analysis software. Exergoeconomic values and variables were obtained using equations based on extant literature. The results reveal that the mixer possesses a low exergoeconomic factor of 5.50% owing to the high irreversibility of the H2O reservoir, flow-mix reservoir, and carbonator. The total hidden cost of the system equaled 733.04 $/h, of which 99.0% is contributed by the mixer. Improvements to the deaeration technique for the H2O reservoir of the mixer component, as well as the H2O treatment procedure, can reduce the irreversibility of the H2O reservoir and the hidden costs.

The cryogenic industry has been experiencing continuous progress in recent years, primarily due to the global development of oil and gas activities. Natural gas liquefaction is a cryogenic process, with the refrigeration system being crucial to the overall process. The objective of the study presented herein is to carry out an exergoeconomic assessment for a dual nitrogen expander process used to liquefy natural gas, employing the SPecific Exergy COsting (SPECO) methodology. The air coolers and throttling valve are dissipative components, which present fictitious unit cost rates that are reallocated to the final product (Liquefied Natural Gas). The liquefaction process has an exergy efficiency of 41.89%, and the specific cost of liquefied natural gas is 292.30 US$/GJ. It was verified that this cost increased along with electricity. The highest exergy destruction rates were obtained for Expander 1 and Air cooler 2. The highest average cost per exergy unit of fuel was obtained for the vertical separator, followed by Air coolers 1 and 2. An assessment of the exergoeconomic factor indicated that both expanders could benefit from a decrease in exergy destruction, improving the exergoeconomic performance of the overall system. Regarding the relative cost difference, all compressors presented high values and can be enhanced with low efforts.

Multi-Objective optimization of propane pre-cooled mixed refrigerant (C3MR) LNG process is performed with two objective functions: (a) maximizing the exergy efficiency and (b) minimizing the total cost of the product. The process simulation is developed using Aspen Plus, while the feasible solutions are produced using non-dominated sorting genetic algorithm II (NSGA-II). The results from exergy-based analysis revealed that when the exergetic efficiency is maximized, the total cost of product has increased from 5047$/h to 52776 $/h, with 71% of the investment costs come from precooling heat exchangers and main cryogenic heat exchangers. On the contrary, when the total cost of product is minimized, the total investment cost is reduced by 18% at the expense of exergetic efficiency. At the lowest cost of product, the total exergy destruction has increased to 111.4 MW or 38% higher compared with the case of maximization of exergetic efficiency. The optimization shows the range of Pareto feasible solutions are between 0.557 and 0.613 for exergetic efficiency and between 45600 and 52776 $/h for the total cost of product. This study demonstrates the approach to solve a multi-objective problem and to find Pareto front for an LNG process without imposing any weighted preferences to the objective functions. • Propane pre-cooled mixed refrigerant process are analyzed using exergy-based methods and optimized with genetic algorithm. • Multi-objective optimization is the combination of the exergy-based methods and non-dominated sorting genetic algorithm II. • Over 70% of the investment costs associated with pre-cooling heat exchangers and main cryogenic heat exchanger. • The total product cost minimization: the total investment cost is reduced by 18% while the exergetic efficiency decreased. • Pareto front for the two objective functions is shown at 100th generations. [ABSTRACT FROM AUTHOR]

In recent years, growing concerns have arisen due to the tight energy supply and escalating demand have driven the research on energy-efficient polygeneration systems. Liquefied natural gas (LNG) is highly regarded as a clean fossil fuel, capable of both cooling and serving as a heat source. This makes it a favored choice for thermodynamic system design. LNG gasification at −162 °C under standard pressure releases substantial cold energy. To avoid its waste, a novel self-supplying thermodynamic system was devised to recover this energy, incorporating a specific cold storage module that combines power generation and heating systems. This approach offers insights into creating polygeneration systems using LNG as the sole energy source. In light of the intricate energy exchanges within the system, based on the energy parameters of each stream, a comprehensive evaluation of its engineering feasibility is conducted through the analysis of energy, exergy, exergoeconomic, and exergoenvironmental parameters. Additionally, key parameters like R1150 mass flow rate, pump 3 outlet pressure, compressor 2 outlet pressure, LNG pump outlet pressure, and R23 liquefaction temperature are examined. Finally, the non-dominated sorting genetic algorithm II (NSGA-II), particle swarm optimization (PSO) and the multi-objective artificial hummingbird algorithm (MOAHA) rooted in hummingbird foraging behavior, are applied to optimize the proposed system. The results show that the energy utilization efficiency, exergy efficiency, product unit exergoeconomic cost, and product unit exergoenvironmental impact are 72.08%, 45.45%, 98.04 $/GJ, and 1.478 × 10−2 mpt/kJ, respectively. These excellent performance indicators demonstrate that the system is developable in the field of LNG utilization, filling a gap in the joint research of cold storage, power generation and heating for LNG cold energy utilization. Enhancing system performance can be achieved by increasing the mass flow rate of R1150 and the output pressure of compressor 2, reducing the output pressure of pump 3 and the liquefaction temperature of R23. When increasing the output pressure of LNG pump, can only increase exergy efficiency, while the energy utilization efficiency, product unit exergoeconomic cost and product unit exergoenvironmental impact all go down. Compared with the initial condition, after the application of MOAHA optimization, the exergy efficiency increased by 2.8%, the product unit exergoeconomic cost decreased by 3.47 $/GJ and the product unit exergoenvironmental impact decreased by 0.047 × 10−2 mpt/kJ. These results outperform those of NSGA-II and PSO, indicating that MOAHA can lead to superior system performance by overcoming multi-objective conflicts. This study provides valuable insights for designing and optimizing LNG cold energy utilization systems in situations without nearby heat sources or when power generation, heating, and cold storage are required. [ABSTRACT FROM AUTHOR]

• BOG cold exergy and PTORC are employed to recover waste heat of a PEM fuel cell. • The PEM fuel cell is simulated mathematically and results are validated. • Thermodynamic and exergoeconomic analyses are performed for the system. • A parametric study is considered to illustrate effects of important parameters. • Proposed system generates 1353 kW power and overall total cost rate is 154.66 $/h. A heat recovery system is employed for power generation from a PEM fuel cell's waste heat. The proposed system involves the parallel organic Rankine cycle for utilizing the provided heat and hydrogen boil-off gas (BOG) stream as a heat sink for the cycle. Also, this stream generates power by using an expander and prepares some chilled water that enhances system performance. The PEM fuel cell as the major component of the system is modeled and then the parallel two-stage ORC (PTORC) and BOG streams are analyzed in points of the energy and exergy view. Exergoeconomic concept is applied to evaluate the economic view of the system besides energy and exergy analyses. Also, a sensitivity analysis is performed by system key parameters which provided some valuable information to comprehend the performance of the overall system. The results show that the proposed system can generate 1353 kW power. Exergoeconomic factor, energy efficiency and exergy efficiency of the overall system are computed to be 26.21%, 58.15%, and 36.64%, respectively. Also, it is concluded that the higher current density and lower operating temperature, will raise the total cost rate. [ABSTRACT FROM AUTHOR]

The study presented here concerns a comprehensive investigation on exergoeconomic analysis and optimization of an integrated system for photoelectrochemical hydrogen and electrochemical ammonia production. The present integrated system consists of a solar concentrator, spectrum-splitting mirrors, a photoelectrochemical hydrogen production reactor, a photovoltaic module, an electrochemical ammonia production reactor and support mechanisms. Detailed thermodynamic and exergoeconomic analyses are initially conducted to determine the performance of the integrated system namely; efficiency and total cost rate. The obtained performance parameters are then optimized to yield the minimum cost rate and maximum efficiency under given constraints of the experimental system. The highest capital cost rates are observed in the photoelectrochemical hydrogen and electrochemical ammonia production reactors because of high procurement costs and electricity inputs. The optimized values for exergy efficiency of the integrated system range from 5% to 9.6%. The photovoltaic and photoelectrochemical cell areas and solar light illumination mainly affect the overall system efficiencies. The optimum efficiencies are found to be 8.7% and 5% for the multi-objective optimization of hydrogen production and integrated ammonia production system, respectively. When the exergy efficiency of the integrated system is maximized and the total cost rate is minimized at the same time, the total cost rate of the system is calculated to be about 0.2 $/h. The cost sensitivity analysis results of the present study show that the total cost rate of the system is mostly affected by the interest rate and lifetime of the system. Image 1 • Exergoeconomic analysis and optimization of integrated solar based-hydrogen and ammonia production system. • Utilization of concentrated sunlight and split spectrum for achieving higher overall efficiency. • Optimization for maximum efficiency and minimum total cost rate. • Performance investigation of sustainable hydrogen and ammonia production. [ABSTRACT FROM AUTHOR]

• The proposed AEHP systems have lower values of product cost of up to 60% compared to the conventional heat pumps. • The ECOP in the proposed AEHP systems is lower than that in the conventional heat pumps. • The second proposed AEHP system operating with NH 3 /NaSCN has lower product cost at higher T Gen and T Eva2. Two novel absorption-ejection heat pump (AEHP) systems are proposed and their feasibility for supermarkets simultaneous heating and refrigeration is assessed from the viewpoints of thermodynamics and exergoeconomics. The proposed systems' performance is compared with that of a conventional compression heat pump. In this study, three different working pairs including NaSCN/NH 3 , LiNO 3 /NH 3 and H 2 O/NH 3 are utilized for the analyses. Simulations show that the ECOP of the conventional heat pump (system 1) is about 8% and 14% lower than that of the first and second proposed AEHP systems (systems 2 & 3), respectively. Moreover, system 3 has a total product cost of up to 10% and 60% lower than that for systems 2 and 1, respectively. Using NH 3 /LiNO 3 solution on the other hand, can better improve the performance at lower refrigeration evaporator temperatures. Regarding the price of electricity, the proposed systems have economic justification only at electricity costs higher than 9 cent/kWh. [ABSTRACT FROM AUTHOR]

Highlights • Exergy, exergoeconomic and exergoenvironmental analyses were applied to an engine. • The effects of engine load and biodiesel concentration were verified. • LCA were developed for diesel and biodiesel. • Specific cost of biodiesel was higher, but presented lower environmental impacts. • Specific environmental impacts decreased with higher power or biodiesel concentration. Abstract The use of biodiesel produces less pollution than petroleum diesel, and any application that utilizes diesel fuel can use biodiesel. However, the intention is not to fully substitute petroleum diesel but to help extend the usefulness of petroleum, supporting the longevity and cleanliness of diesel engines, and possibly create a balanced energy policy. This study employed exergy, exergoeconomic and exergoenvironmental analyses to verify the effect of engine load and biodiesel concentration in a stationary, direct injection diesel engine. The Life Cycle Assessment methodology was applied within Simapro software to quantify the environmental impacts associated with the consumption of diesel and biodiesel, utilizing the Eco-indicator 99 environmental impact assessment method. Analyses included the calculation of exergy efficiency, specific cost, specific environmental impacts, and exergoeconomic and exergoenvironmental impact factors. It was verified that full load operation presented the best results in all analyses. Exergy analysis revealed that low biodiesel concentration presented slightly higher efficiency. Although the specific cost of biodiesel was double the specific cost of diesel (1.55 US$/kg versus 0.76 US$/kg), biodiesel presented lower environmental impacts (55.8 mPt/kg versus 240 mPt/kg for diesel). It was verified that exergy efficiency increased along with capacity load, but increases in the concentration of biodiesel yielded lower exergy efficiencies. The exergoeconomic factor decreased as exergy destruction and exergy losses increased, and specific environmental impacts decreased with increases in power or in biodiesel concentration. A case is made for the outstanding benefits around understanding how environmental impacts are formed to pinpoint where changes should be implemented (herein, focus is on fuel and pollutant formation). [ABSTRACT FROM AUTHOR]

Abstract Exergy-based methods are powerful tools for developing, evaluating, understanding, and improving energy conversion systems. This paper deals with integrated advanced exergy-based evaluations. In addition to conventional methods, advanced exergy-based analyses consider (a) the interactions among components of the overall system, and (b) the real potential for improving each important system component. The main role of an advanced analysis is to provide energy conversion system designers and operators with information useful for improving the design and operation of such systems. Splitting the exergy destruction, the capital investment cost, and the component-related environmental impact associated with each single component of an energy conversion system into endogenous/exogenous and avoidable/unavoidable parts and using a further splitting of the exogenous exergy destruction improves (a) our understanding of the processes that take place, and (b) the quality of the conclusions for improvement obtained from the analysis. This paper discusses the main features and some recent developments in the area of advanced exergy-based methods. Application of the method to a simple air refrigeration machine confirms the correctness of the approach. [ABSTRACT FROM AUTHOR]