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Hybrid solar–biomass organic Rankine cycle (ORC) systems represent a promising avenue for sustainable energy production by combining abundant but intermittent solar energy with the reliable biomass energy. This study conducts a detailed thermodynamic and economic assessment of these hybrid systems, focusing on their potential to enhance energy efficiency and reduce greenhouse gas emissions. The study also evaluates the performance of various working fluids, identifying optimal configurations for different operating conditions. A key finding is that the hybrid system, with an optimized solar–biomass ratio, achieves up to a 21 to 31% improvement in efficiency and a 33% reduction in levelized cost of electricity (LCOE) compared to solar-only systems. Additionally, the study examines case studies of real-world applications, offering insights into the scalability and cost-effectiveness of these systems in regions with high solar irradiation and biomass availability. These results underline the need for continued technological innovation and policy support to promote widespread adoption of hybrid ORC systems, particularly in the context of global decarbonization efforts. [ABSTRACT FROM AUTHOR]

Natural gas stations require a preheating stage to prevent the formation of hydrates inside of them provoked by a sudden decompression process of the natural gas. The preheating process has been investigated to improve efficiency and to reduce costs as well. This work studies the behavior of a natural gas decompression station with a first-stage preheating process using a vortex tube and a geothermal heat exchanger, followed by a second stage involving a water bath heater (heating vat). An energetic, exergetic, and exergoeconomic study has been carried out based on a mathematical model and the theory of exergetic cost, obtaining key thermodynamic and thermoeconomic variables, including exergy flows and equipment costs. A heat flow of 26.41 kW was obtained in the geothermal preheating stage; meanwhile, a 60.43 kW heat flow was obtained in the heating vat. The results showed a saving in station fuel using only 2.046% of the natural gas in the system at the second preheating stage. Also, the system was optimized, obtaining a 15.73% reduction in the decompressed natural gas cost. These findings show the possibility of implementing these systems in zones with many geothermal resources to reach a constant, profitable natural gas supply in areas where a pipeline network does not exist. [ABSTRACT FROM AUTHOR]

Liquefaction of natural gas (LNG) is an energy-intensive process with large CO2 emissions. This study addresses these problems by introducing a novel hybrid integration between the propane pre-cooled mixed-refrigerant (C3MR) liquefaction process and concentrated solar power (CSP), utilizing an intercooled supercritical CO2 power block. The proposed system is designed to minimize or eliminate the need for thermal energy storage (TES) and reduce CO2 emissions while providing economic benefits. These benefits are obtained mainly by recovering the cold energy of the flash-gas of the C3MR process through the precooling process of the sCO2 cycle. Then, the flash-gas is stored and combusted (using an auxiliary heater (AH)) at nighttime or when CSP is insufficient to meet the power demand. Five integration cases are evaluated from energetic, exergetic, economic, and environmental points of view: the sCO2 cycle is driven by CSP and its thermal energy storage (TES) without AH in Case-1, by CSP+TES+AH in Case-2 to Case-4 with different contribution from TES and AH, and by CSP+AH without TES in Case-5. In addition, this study optimizes the operating parameters of the hybrid system to further enhance its economic and environmental benefits. The proposed system reduces the CSP field size, minimizes or eliminates the need for TES, and reduces or eliminates CO2 emissions. The optimized results show that Case-2 and Case-5 reduced the levelized cost of electricity from 14.16¢/kWh to 10.35¢/kWh and 8.19¢/kWh, respectively, and reduced the CO2 emissions by 86% and 36%. This study contributes to the field by introducing a novel hybrid integration between the C3MR process and CSP system, providing thorough evaluations of its performance and benefits, and providing significant benefits to the decarbonization strategies of LNG and other industrial processes.

In this study, a thermodynamic model was designed with the Aspen Plus program and optimized multidimensionally of the Afyon biogas power plant to reduce the unit electricity cost and produce green hydrogen. The model also includes ORC integration to use the exhaust gas energy of the existing power plant. In the model, which includes the whole process from biomass receiving to final electricity production, the plant produces 4000 kW of net electrical power. As a result of ORC integration and optimization, the net electricity production of the plant and ORC were determined as 4625.42 kW and 1215.31 kW, respectively. These values correspond to 0.039 $/kWh unit electricity cost. The power obtained in ORC is stored by producing hydrogen during periods of low electricity demand. For this purpose, ORC power is primarily used to electrolyze H2S (green hydrogen) released in biogas production. The rest of the power is used in the electrolysis of water. Hydrogen, released in biogas production, is added to the storage process. As a result, approximately 7.447 kg/min of hydrogen is produced at the power plant, costing 0.18 $/kg. [ABSTRACT FROM AUTHOR]

The advanced exergy and exergoeconomic analysis methodologies excel over their conventional counterparts by quantifying endogenous/exogenous exergy destruction rates and related costs that reveal the interactions among system components. By quantifying avoidable/unavoidable losses, they also reveal the potentials for component improvements that are practically achievable. These data are imperative for improving the cost-effectiveness of thermal systems. This paper presents the performances of a complex gas-fired power plant obtained via an advanced exergoeconomic analysis. The study advances existing studies by undertaking second-tier splitting of exergy destruction cost rates and associated investment cost rates to determine avoidable endogenous, unavoidable endogenous, avoidable exogenous, and unavoidable exogenous cost rates of the plant's components. Component exergy destruction cost rates were found to be predominantly unavoidable, while most of the component investment cost rates were avoidable. Except for the low pressure heater 3, exergy destruction cost rates are endogenous in all the plant components, contributing 84% of overall cost rates. The proportions of exergy destruction cost rates and investment cost rates of the plant that are avoidable endogenous were 21% and 28% respectively, while the respective portions that are avoidable exogenous were 4% and 27%. Furthermore, it was shown that as much as 96.3% improvements in overall plant cost-effectiveness were achievable by eliminating avoidable endogenous exergy destruction cost rates and investment cost rates for major components of the plant. [ABSTRACT FROM AUTHOR]

The choice of refrigerant and expander is always one of the main concerns of researchers using organic Rankine cycles. The problem of using the organic Rankine cycle becomes more complicated when there are two waste heat sources with different temperatures in a system, such as exhaust gas and jacket water heat sources in an internal combustion engine. Hence, in this paper, a thermoeconomic program is developed using four types of volumetric expanders, including piston, screw, scroll and root, and eight different organic fluids in the series double cascade-evaporator organic Rankine cycle. The studied organic fluids were selected to cover a wide range of pressure levels in the series double cascade-evaporator organic Rankine cycle, including R245 FA, R123, n-pentane, acetone, n-heptane, benzene, n-octane and toluene. In the present study, 16 different pairs of expanders were examined for a cohort of 8 dissimilar fluids, resulting in an aggregate of 128 distinctive cases. In each of the 128 different cases, the important parameters, including power production, exergetic efficiency, total investment cost, net present value and levelized cost of electricity generation, are calculated. Also, the Pareto method is used to select the best organic fluid and expander pair. The results show the fluids with lower critical temperatures performed better due to the pressure ratio limit. The lowest cost of the expander compared to the total cost was 4.98%, related to the pair of root–scroll expanders, and the highest cost of 48.21% was related to the piston–screw expander pair. The lowest total investment cost was 377,478$ for the n-pentane and the piston–scroll expander pair. The screw expander costs more than other expanders, especially when in the low-pressure cycle. According to the optimization results, the optimal pair of expanders for the series double cascade-evaporator organic Rankine cycle system is scroll–scroll with n-pentane as the working fluid. Additionally, the exergetic efficiency, payback period and total investment cost values in this case are 0.3945, 4.089 years and 385,786$, respectively. [ABSTRACT FROM AUTHOR]

This research presents the proposal of a double ejector-two flash tank absorption refrigeration cycle, in which vapor and liquid ejectors are implemented simultaneously before the condensers and absorbers components. For the vapor ejector simulation, the shock circle approach is used. The internal environment of the vapor ejector, including the chocking phenomenon and the irreversible shock process, is also thoroughly examined. It is proposed that ejectors and flash tanks can improve the system performance. It is possible to improve the ejector entrainment ratio by incorporating a flash tank between the evaporator and condenser, which would also increase the evaporator cooling effect. Moreover, a second flash tank is installed between the generator and the absorber, which allows the generator to operate at a lower temperature and thus reduces the generator heat load. Consequently, the system's COP (coefficient of performance) increases. Furthermore, the unit cost of the final product in a wide range of operational conditions is calculated. The findings revealed up to 56.8% increase in the COP. The improvement of the maximum exergetic efficiency in the new cycle compared to the basic cycle also reaches 22.5%. Moreover, the thermoeconomic investigation show up to 34.6%. reduction in product cost.

Türkiye is the largest cement producer of Europe and the second biggest cement exporter in the world. The industry is responsible for more than 8% of global carbon dioxide (CO2) emissions and around 15% of the primary energy consumed worldwide. In this paper, the specific energy consumption (SEC) and related emissions of a real scale cement factory currently running in Türkiye have been decreased by investigating the effects of moisture rate of the raw materials and the hot gas transfer to the grinding unit. The data has been collected in the factory site by using the monitoring equipment and real time detection over a 24-month period. Energy and exergy destructions and exergetic cost distributions are determined by using specific exergy costing method (SPECO) for all units of the factory. The specific exergetic consumption (SExC) and production (MC) costs of raw meal are calculated to be 5.05 $/GJ and 4.13 $/ton, respectively. It is investigated that the hot gas supply to the grinding unit and decreasing the moisture rate of feeding materials decreased the SPECO of raw meal, clinker and cement by 8.25%, 5.49% and 4.89% respectively. The applications provide 184.69 MJ reduction in specific energy consumption (SEC) per ton of cement produced and blocked 75,343.37 tons of CO2 emissions per year and reduced the cement production cost to 40.47 $/ton corresponding to a saving of $2.06 M per year. It has been demonstrated that it is very important to keep the moisture content of raw materials used in the cement industry as low as possible in terms of reducing energy consumption and manufacturing costs for sustainable production. [ABSTRACT FROM AUTHOR]

This article presents a novel and comprehensive approach for the thermoeconomic evaluation of subcritical and supercritical isobutane cycles for geothermal temperatures of Tgeo = 100–200 °C. The isobutane cycles are optimized with respect to the maximum net power or minimum levelized cost of electricity (LCOE). Cycle optimization is also included, using a minimum superheat temperature to avoid turbine erosion, which is usually neglected in the literature. The results show that economic optimums are found in the far superheated region, while thermal optimums are obtained with dry saturated or with slightly superheated vapor at the turbine inlet (ΔTsup < 5 °C). Supercritical cycles achieve better thermal performance than subcritical cycles for Tgeo = 179–200 °C. Internal heat recuperation improves the cycle performance: the net power output increases and the LCOE decreases, but specific installation costs (SICs) increase due to the additional heat exchanger. For geothermal temperatures of Tgeo = 120 → 150 °C, the costs are LCOE = 100 → 80 USD2022/MWh and SIC = 7000 → 5250 USD2022/kW, while for geothermal temperatures of Tgeo = 150 → 200 °C, the estimated costs are LCOE = 80 → 70 USD2022/MWh and SIC = 5250 → 4600 USD2022/kW. [ABSTRACT FROM AUTHOR]

A state-of-art multi-generation plant integrated with a scramjet multi-cooling cycle for power, hydrogen, ammonia, and freshwater generation was analyzed from an energy, exergy, exergoeconomic as well as environmental (4E) standpoint. The coolant of the cooling cycle was the fuel of the scramjet cycle and in terms of optimizing consumed power, this cycle is benefiting from four-stage compressors. To improve the rate of hydrogen production, a methanol steam reforming procedure was employed. To provide fresh water, a reverse osmosis membrane was employed and integrated into the plant. To consider the powers of input design variables on the implementation criteria of the plant and reduce CO and CO 2 emission, an exhaustive parametric investigation was performed. The thermodynamic efficiencies, the sum unit cost of the products, the system emission rate, and the environment penalty cost rate as well as values of the products as the multi-generation plant's performance criteria were computed. Raising the hydrogen mole fraction caused an increase in the emission rate. [ABSTRACT FROM AUTHOR]

Enhancing the sustainability and diversification of Iraq's electricity system is a strategic objective. Achieving this goal depends critically on increasing the use of renewable energy sources (RESs). The significance of developing solar-powered technologies becomes essential at this point. Iraq, similar to other places with high average direct normal irradiation, is a good location for concentrated solar thermal power (CSP) technology. This study aims to recover the waste heat from the gas turbine cycle (GTC) in the Al-Qayara power plant in Iraq and integrate it with a solar power tower. A thermoeconomic analysis has been done to support the installation of an integrated solar combined cycle (ISCC), which uses concentrated solar tower technology. The results indicate that the examined power plant has a total capacity of 561.5 MW, of which 130.4 MW is due to the waste heat recovery of G.T.s, and 68 MW. is from CSP. Due to the waste heat recovery of GTC, the thermal and exergy efficiencies increase by 10.99 and 10.61%, respectively, and the overall unit cost of production is 11.43 USD/MWh. For ISCC, the thermal and exergy efficiencies increase by 17.96 and 17.34%, respectively, and the overall unit cost of production is 12.39 USD/MWh. The integrated solar combined cycle's lowest monthly capacity was about 539 MW in September, while its highest monthly capacity was approximately 574.6 MW in April. [ABSTRACT FROM AUTHOR]

The main purpose of this study is to evaluate the thermodynamic and economic performance of using a solar chimney and wind turbine to help generate electricity in a multigeneration system. The proposed system is designed to generate power, heating, cooling, hot water, and steam. Parametric studies were conducted to evaluate the effects of various parameters such as Brayton cycle turbine inlet pressure, organic Rankine cycle turbine inlet temperature, solar radiation, wind speed, and absorption refrigeration cycle evaporator temperature on the system efficiency. The effects of these parameters on the energy, exergy, and economic efficiencies of the whole system were investigated. The results showed that the highest energy efficiency and total exergy of the multigeneration system were 22.12% and 11.4%, respectively. Also, the total power generation capacity of the studied system was calculated to be 2103 kW. The results also depicted that the highest rate of exergy destruction for the main components of the system is found in the parabolic dish solar collector. Increasing the turbine inlet pressure, the average wind velocity of the wind turbine and, evaporator temperature increasing of absorption refrigeration cycle has a positive effect on the efficiency of the proposed system.

In the current energy and environmental framework, the environmental impact of the road transport sector and the urban waste management and disposal are extremely important for highly crowded cities. This work assesses the energy, economic and environmental performance of an innovative paradigm for the full decarbonisation of the road transport sector. This problem is integrated with the management of the organic fraction of municipal solid waste. In particular, the proposed technology is based on an anaerobic digestion plant coupled with a biogas upgrading unit, for the production of biomethane. In addition, photovoltaic panels and solar thermal collectors are also considered for matching electrical and thermal demands, in order to achieve a fully-renewable system. To this scope, the system also includes suitable thermal and electric storages. The economic analysis also considers specific public funding policies, currently available for this technology. This system aims to be a novel paradigm in the energy scenario of waste disposal and road transport sector refurbishment. TRNSYS software was adopted to perform an accurate dynamic simulation for a one-year operation of the system. The anaerobic digestion model is developed by the authors in MatLab and integrated in TRNSYS, for dynamic simulation purpose. Results show that the plant is almost self-sufficient due to the integration of storage systems for both the thermal and electric energy. The photovoltaic system is able to reduce by 45% the energy dependence from the grid. Energy and environmental analyses show a Primary Energy Saving of 126% and a reduction of CO2 equivalent emissions by 112%. The economic feasibility analysis shows a promising Simple Payback period of 6 years.

The improvement of the overall utilization rate of compressed natural gas (CNG) engine fuel is the basis of efficient energy utilization. On the foundation of heat balance theory of internal combustion engines, this study fully considers the operation characteristics of CNG engines and systematically analyzes the distribution characteristics of different waste heat under variable working conditions. The nonlinear relationship between speed and intercooler heat source becomes evident with the increasing of intake mass flow rate. In accordance with the structural characteristics, the thermodynamic model, heat transfer model and environmental model of dual-loop organic Rankine cycle (DORC) are constructed. The system potential in full working environments is systematically evaluated. Compared with the speed, airmass flow has a significant effect on comprehensive performance of loop. The maximum power, heat transfer area and power output of per unit heat transfer area (POPA) of DORC are 36.42 kW, 23.34 m2, and 1.75 kW/m2, respectively. According to the operating characteristics of different loops, the variation laws of loop performance under the influence of multiple parameters are analyzed. The synergistic influence laws of multiple variables on system performance are also analyzed. [ABSTRACT FROM AUTHOR]

This paper considers the possibility of using liquid-vapor ejectors in condensing units of steam turbines. This unit is designed for pumping out a steam-air mixture from a steam turbine condenser, in which the process occurs at a pressure lower than atmospheric. In the traditional scheme, this is provided by a two-stage steam-jet ejector unit. The proposed scheme involves the use of a single-stage liquid-vapor ejector and its possible pre-vacuum mode of operation in conjunction with a liquid- ring vacuum pump. A working process of the liquid-vapor ejector does not require the supply of working steam from the outside since its generation occurs in the active nozzle of the liquid-vapor ejector. A description of the traditional scheme and the proposed options is given, which are different both in the scheme solution and in the ope rating parameters. The object of this study is a liquid-vapor ejector, which is used in the condensing system of a steam turbine. Thermodynamic calculation of the proposed circuit solutions was carried out. As a result, the necessary mode parameters of the schemes were determined. To assess the feasibility of using a liquid-vapor ejector in the condensation systems of steam turbines, an exergy analysis was performed. The proposed scheme makes it possible to increase efficiency by 2.3 times, and when used with a liquid-ring vacuum pump – by 2.44 times. To assess the economic efficiency of the modernization of the condensing system, thermoeconomic analysis was performed. The use of the proposed scheme makes it possible to reduce the cost of generating boiler steam and reduce the cost of the resulting product of the steam turbine unit by about 51 %. The estimated cost of a unit of the amount of boiler steam consumed per ton of product and the unit cost of steam were established [ABSTRACT FROM AUTHOR]

Compressed-air energy storage has been considered as a promising technology to smooth the fluctuations of renewable energy sources and improve the peak-shaving flexibility capacity of power systems. In order to improve the energy degree of compression heat and enhance the system performance, the current paper described a novel combined heating and power system that integrates compressed-air energy storage with thermochemical technology. In the proposed system, the compression heat is coupled with methanol decomposition reaction to convert the thermal energy to chemical energy (H2 and CO). A sensitivity analysis was carried out to investigate the effects of five key parameters on the system performance. The results indicated that higher values of air-to-methanol ratio, pressure ratio, and isentropic efficiency of gas turbine have positive influences on the thermodynamic performance of the proposed system. In addition, the multiobjective optimization was implemented to ascertain the optimum performance from the aspect of thermodynamics and economics. The optimal condition selected using the technique for order preference by similarity to an ideal solution (TOPSIS) method demonstrated that the exergy efficiency and levelized cost of energy of the proposed system are 39.42% and $96.58/MWh , respectively. [ABSTRACT FROM AUTHOR]

The maritime industry will continue to see increasing regulatory requirements to reduce carbon emissions from ships' operations. Improving the energy efficiency of ships with waste heat recovery systems based on the organic Rankine cycle (ORC) is an attractive way to meet these tightening requirements. The operational profile of a ship has a huge influence on the feasibility of installing ORC onboard as it affects the waste heat source profile from the diesel engines. However, to date, scant attention has been paid to examining the effects that the operational profile has on the marine application of ORC as it is both difficult and expensive to obtain. The present paper aims to describe a methodology that can overcome this problem by developing a generic ship speed profile that defines the ship's operational profile. This speed profile works together with a fit-for-purpose diesel engine waste heat model to derive a waste heat source profile that is used as the input to a thermoeconomic analysis that can justify the installation of ORC. The proposed methodology allows for an objective comparison of the feasibility of ORC subjected to variations in the operational profile. Furthermore, the optimum ORC design can be identified to meet payback time expectations of different shipowners. [ABSTRACT FROM AUTHOR]

Summary: For the global future energy systems, concentrated solar power (CSP) and direct CO2 capture systems are of the most important key technologies, however, each of these systems has shortcomings. This study addresses the solar intermittency and power control complexity of the CSP systems and the substantial energy penalty of the direct oxy‐combustion (DOC) supercritical carbon dioxide (sCO2) power systems by integrating both systems. Herein, innovative power cycle configurations that integrate the CSP tower system with DOC sCO2 power cycle are introduced. The configurations include two basic cycles for comparison and validation purposes and three integrated cycles. The basic configurations are: an intercooled sCO2 power cycle driven by DOC system (S1), and a stand‐alone basic CSP tower system (S2). The integrated configurations are: CSP/DOC system where the CSP works as a preheater (S3); CSP/DOC system where the CSP works as a reheater (S4); and CSP/DOC system where each system heats part of the working fluid to drive its high‐pressure turbine (S5). The hybrid configurations reduce the fuel and the parasitic power consumptions of the basic DOC systems (S1) and reduce the capital cost associated with the conventional CSP systems (S2) by eliminating the need for thermal storage. Over practical ranges of operational parameters, comprehensive thermoeconomic, exergoeconomic, and optimization analyses for the proposed configurations are performed. Compared to the conventional CSP system, the LCOE of the hybrid system is lower by 50%. Among the hybrid configurations, the energetic and exergetic performances of S4 are the best with the lowest LCOE. According to the optimization analysis, S4 has a thermal efficiency of 55.29% at LCOEs of 7.705¢/kWh. S3, S5, S2, and S1 have thermal efficiencies of 52.90%, 48.72%, 45.56%, and 40.54% at LCOE of 7.970, 8.138, 7.864, and 6.351¢/kWh, respectively. [ABSTRACT FROM AUTHOR]

The heat pumps are frequently used in domestic and industrial applications for hot water supply. The present paper aims to thermodynamically investigate the impacts of the nanoparticle-addition into the lubricants on the energetic, exergetic, and thermoeconomic aspects of a heat pump. In the experiments, air to the water heat pump is separately charged with various metal oxide-based nanoparticles (Al2O3, CuO, and TiO2)-added oils at a constant mass fraction of 0.5%. Polyolester (POE) and 134a are used as a lubricant, and refrigerant, respectively. The mass flow rates of the water passed through the condenser are varied from 10 to 25 g/s with an interval of 5 g/s. In the results, it is observed that the thermal conductivity value noteworthy increases with the presence of nanoparticles in POE. The highest increment in thermal conductivity is found to be 39% for POE + CuO in comparison with that of pure POE. Furthermore, with nanoparticles addition, it is noticed that the COP value generally improves, and the highest improvement for COP value is noticed to be 8% for POE + TiO2 nanolubricant at the mass flow of 25 g/s. Furthermore, exergy efficiency enhances by 3.6%, 1.8%, and 4.5% for POE + Al2O3, POE + CuO, and POE + TiO2, respectively. The lowest heating cost is calculated to be 3.465 ¢/kWh at 20 g/s flow rate for POE + Al2O3. In conclusion, this paper clearly reports that usage of nanoparticles along with lubricants is presenting better energetic, exergetic, and thermoeconomic results rather than the usage of lubricant alone in the heat pumps.

Evaluating Coal-Fired Power Plant (CFPP) performance is a complex process involving the determination of the turbine cycle Heat Rate (TCHR). This study focuses on determining the TCHR by developing a mathematical model. The model, which incorporates economic analysis of the plant, is developed using energy and mass balance relationships of the turbine cycle, validated using plant commissioning data from a 700MWn CFPP located in Perak, Malaysia. Actual plant data from a 700MWn CFPP is utilized to improve the accuracy and increase the confidence of the results of this study. It was found that at the nominal operating load of 729MWg, there is a Heat Rate (HR) deviation of -1,135 kJ/kWh, leading to daily losses of RM240,447 or USD 60,112. Furthermore, it is possible to utilize the developed model at lower loads as the plant is now being used to operate on "cyclic" loads. The daily losses at a lower load of 431MWg are RM125,767 or USD31,442. Thus, the model is able to compare the plant HR at various loads against commissioning data, and economic analysis is able to be carried out effectively. Valuable information for plant operations and performance engineers could be obtained using this model to determine plant HR. [ABSTRACT FROM AUTHOR]

Because of the fossil fuels crisis in recent years, increasing fossil fuel consumption and the oil crisis, energy efficiency is becoming a major concern of the twenty-first century. In this research, the combined cycle of steam Rankine and organic Rankine with the primary mover of the Allam generation cycle has been simulated. The hybrid cycle is configured in such a way that the high temperature waste heat first acts as the steam cycle evaporator and the waste heat output from the steam cycle evaporator is used as the low temperature evaporator of the organic cycle. Then, the effect of changing various parameters such as evaporator temperature and steam cycle condenser pressure on output work values, total irreversibility, energy efficiency, exergy efficiency and exergy-economic variables is investigated. The results show that the energy efficiency and exergy efficiency of the combined cycle are 0.57 and 0.66, respectively, and the amount of output work and total irreversibility are 150,125 kW and 91,237 kW, respectively. Also, according to the study results, a lot of exergy destruction takes place in the system, thus it is recommended to increase the initial price in different components in order to improve the performance of the system. Evaporators and steam cycle condensers are components that should be considered from an exergy-economic perspective, as they have the highest rate for the sum of the initial cost rate and the cost of exergy destruction. [ABSTRACT FROM AUTHOR]

In this paper, a salinity gradient solar pond (SGSP) is used to harness the solar energy for hydrogen production through two cycles. The first cycle includes an absorption power cycle (APC), a proton exchange membrane (PEM) electrolyzer, and a thermoelectric generator (TEG) unit; in the second one, an organic Rankine cycle (ORC) with the zeotropic mixture is used instead of APC. The cycles are analyzed through the thermoeconomic vantage point to discover the effect of key decision variables on the cycles' performance. Finally, NSGA-II is used to optimize both cycles. The results indicate that employing ORC with zeotropic mixture leads to a better performance in comparison to utilizing APC. For the base mode, unit cost product (UCP), exergy, and energy efficiency when APC is employed are 59.9 $/GJ, 23.73%, and 3.84%, respectively. These amounts are 47.27 $/GJ, 29.48%, and 5.86% if ORC with the zeotropic mixture is utilized. The APC and ORC generators have the highest exergy destruction rate which is equal to 6.18 and 10.91 kW. In both cycles, the highest investment cost is related to the turbine and is 0.8275 $/h and 0.976 $/h for the first and second cycles, respectively. In the optimum state the energy efficiency, exergy efficiency, UCP, and H 2 production rate of the system enhances 42.44%, 27.54%,15.95%, and 38.24% when ORC with the zeotropic mixture is used. The maximum H 2 production is 0.47 kg/h, and is obtained when the mass fraction of R142b, LCZ temperature, pumps pressure ratio, generator bubble point temperature are 0.603, 364.35 K, 2.12, 337.67 K, respectively. • The stored heat of a salinity gradient solar pond is used for H 2 production. • Thermoelectric generators and zeotropic mixture are employed. • NSGA-II is used to find the optimum point of the system. • In optimum state η e n , η e x , UCP, and m ˙ H 2 are 6.31%, 34.63%, 44.7 $/GJ, and 0.47 kg/h. [ABSTRACT FROM AUTHOR]

Solar energy systems are widely utilized to obtain environmentally friendly and sustainable electrical and thermal energy that able to be used in many applications. Temperature-controlled solar air heater (SAH) system with a zigzag finned plate and flat plate was designed, manufactured, and tested experimentally in this study. It was determined that the set temperature was 15% higher than the flat plate SAH outlet temperature. The most important cause for this increase, the air is exposed preheating in the first collector. As the heat transfer surface area raised thanks to the zigzag fins in the second collector, the temperature of the air increases even more. SAH system's energy efficiency was found to be 71.15% on average. SAH system's maximum exergy efficiency was determined as 3.7%. The SAH system's average exergy destruction is calculated to be 651.58 W on average. According to the enviroeconomic analysis of the system, hourly CO2 mitigation was found to be 1.04 kg CO2/h and the environmental cost was 1.508 ¢/h. The energy cost was calculated as 0.0834 $/kWh, while the exergoeconomic parameter was calculated as 0.1931 kWh/$. In addition, the energy payback period was determined as 1.35 years, while the exergy payback period was determined as 45.9 years.

To address environmental pollution effectively, it is crucial to promote the increased utilization of renewable energy sources. Furthermore, an appealing opportunity arises from enhancing the efficiency of renewable-based power plants while diversifying their product output. This study introduces a hybrid system that revolves around renewable resources, with a primary focus on evaluating power generation, hydrogen production, and freshwater extraction. The designed system seamlessly integrates a flash-binary geothermal power plant with a solar system, incorporating cutting-edge phase-change material storage technology. Hydrogen is generated through a combination of steam-methanol reforming and pressure swing adsorption processes. Freshwater is procured utilizing humidification-dehumidification and multi-effect desalination units. In terms of power generation, the system leverages the capabilities of the geothermal power plant alongside a modified Kalina cycle. The performance of this integrated system is rigorously evaluated through a combination of thermodynamic and thermoeconomic approaches. An exergy-economic optimization scenario is employed to determine the most efficient operational mode. The results of this comprehensive analysis reveal that the system can produce 0.0224 kg/s of hydrogen, 8.017 kg/s of freshwater, and generate 215.9 W of net power. Impressively, it achieves an exergy efficiency of 58.3% at a unit cost of $32.23/GJ in the base mode. Furthermore, the optimal operating state boosts efficiency to 60.59%, with a unit cost of $32.22/GJ. Notably, adjustments in the selling price of hydrogen have a significant impact on the system's financial metrics. As the price of hydrogen rises from $5 to $6/kg, the payback period reduces from 4 to 3 years, and the net present value surges from $5.81 million to $10.16 million. • A renewable-based hybrid system is proposed for power, hydrogen, and freshwater production. • Integration of geothermal power plant, solar system, and various desalination units. • Comprehensive thermodynamic and thermoeconomic analysis conducted for system evaluation. • The optimum state achieves 60.59% exergy efficiency and a unit cost of 32.22 $/GJ, with significant financial benefits. [ABSTRACT FROM AUTHOR]

The maritime industry will continue to see increasing regulatory requirements to reduce carbon emissions from ships’ operations. Improving the energy efficiency of ships with waste heat recovery systems based on the organic Rankine cycle (ORC) is an attractive way to meet these tightening requirements. The operational profile of a ship has a huge influence on the feasibility of installing ORC onboard as it affects the waste heat source profile from the diesel engines. However, to date, scant attention has been paid to examining the effects that the operational profile has on the marine application of ORC as it is both difficult and expensive to obtain. The present paper aims to describe a methodology that can overcome this problem by developing a generic ship speed profile that defines the ship’s operational profile. This speed profile works together with a fit-for-purpose diesel engine waste heat model to derive a waste heat source profile that is used as the input to a thermoeconomic analysis that can justify the installation of ORC. The proposed methodology allows for an objective comparison of the feasibility of ORC subjected to variations in the operational profile. Furthermore, the optimum ORC design can be identified to meet payback time expectations of different shipowners.

Humidification-dehumidification (HDH) desalination systems are popular among researchers due to their simple structure, ability to operate with low-grade and renewable energy sources, and the capacity to work with high-concentration water. This paper presents a thermodynamic and thermoeconomic analysis of an HDH system with a multi-stage bubble column dehumidifier. There was a lack of economic studies on bubble column dehumidifier systems in previous literature; also, no research had examined the impact of different geometric and temperature parameters on the entire system's performance. The fixed surface method was used to model the humidifier and dehumidifier, and the effect of mass flow rate ratio, top and bottom temperature, pipe length within each dehumidification stage, and the number of dehumidifier stages on the system's performance was studied. System performance was compared under various conditions, including gain output ratio (GOR), water production, and cost of produced freshwater. The highest GOR is obtained in the highest pipe length and the highest number of dehumidifier stages. Increasing the length of the pipe and the number of dehumidification stages increases the cost, so achieving the lowest cost of produced water is a compromise between higher cost and higher efficiency. The system achieved a GOR of 3.03, the lowest cost price of produced water is 18.29 $ m 3 , and the highest acheived exergy efficiency is 22.4 %. • An HDH system with multi-stage bubble column dehumidifier is proposed. • A thermoeconomic model has been developed to analyze this system. • A novel approach is introduced for the purchase cost of a bubble column dehumidifier. • Effects of physical and geometric parameters on system performance are investigated. • The unit cost of water production in different conditions is presented. [ABSTRACT FROM AUTHOR]

Clean energy development for multiple productions interests many countries and companies. Hence, this paper presents an innovative solar-driven trigeneration arrangement equipped with a thermal energy storage unit (TESU); the whole system comprises parabolic dish collectors, a modified Rankine cycle, and a double-effect absorption chiller. The system is designed to enhance the integrity performance compared to previous designs. Heat loss recovery is performed using an internal heat exchanger to improve the Rankine cycle's performance. The operating framework of the arrangement contains three steady modes: solar mode associated with the state without applying TESU, storage mode corresponding to the state without solar energy using TESU, and solar-storage mode capable of storing energy in addition to launching the combined cycles. The prediction of the sensitivity of the net output power, heating capacity, input energy, power to heating and cooling ratios, and energy and exergy efficiencies is conducted in solar mode. Furthermore, the thermoeconomic analysis is carried out in solar mode to determine the equipment's financial aspect. Referring to the results, the overall energy efficiencies of the modes introduced before are equal to 97.23%, 81.98%, and 40.23%, and the corresponding exergy efficiencies are 15.53%, 14.47%, and 8.58%. Also, the exergoeconomic factor of the solar subsystem is 70.77%. [Display omitted] • Modeling a CCHP system based on a modified Rankine cycle, a double absorption chiller, parabolic dish collectors and a TSU. • Improving the trigeneration system's performance by eliminating the examined models' weaknesses. • Analyzing solar dish collector systems' thermodynamic and exergoeconomic. [ABSTRACT FROM AUTHOR]

In this study, aviation, energy, exergy, environmental, exergoeconomic, and exergoenvironmental analyses are performed on a CFM56-3 series high by-pass turbofan engine fueled with Jet-A1 fuel. Specific fuel consumption and specific thrust of the engine are found to be 0.01098 kg/kN.s and 0.3178 kN/kg/s, respectively. Engine's energy efficiency is calculated as 35.37%, while waste energy ratio is obtained as 64.63%. Exergy efficiency, waste exergy rate, and fuel exergy waste ratio are forecasted as 33.32%, 33175.03 kW, and 66.68%, respectively. Environmental effect factor and ecological effect factor are computed as 2.001 and 3.001, while ecological objective function and its index are taken into account of −16597.22 kW and −1.001, respectively. Exergetic sustainability index and sustainable efficiency factor are determined as 0.5 and 1.5 for the CFM56-3 engine, respectively. Environmental damage cost rate is determined as 519.753 $/h, while the environmental damage cost index is accounted as 0.0314 $/kWh. Specific exergy cost of the engine production is found as 40.898 $/GJ from exergoeconomic analysis, while specific product exergy cost is expressed as 49.607 $/GJ from exergoenvironmental analysis. From exergoenvironmental economic analysis, specific exergy cost of fuel is computed as 10.103 $/GJ when specific exergy cost of production is determined as 40.898 $/GJ. • CFM56-3 high by-pass turbofan engine used in Boeing 737 aircraft is assessed. • Real measured data of the CFM56-3 series high by-pass turbofan engine is used. • Energy, exergy, economic, environmental, and sustainability analyses are applied. [ABSTRACT FROM AUTHOR]

District Heating (DH) systems, owing to their remarkable techno-economic benefits compared to decentral heat production methods, are getting more and more popular worldwide. Today, DH systems are much more efficient than in the past but investigations show that there is still much to explore for more benefits and higher efficiencies considering such systems, where lowering the operating temperature is one of the points with the highest potential advantages. This study evaluates the effects of using different levels of operation temperatures of DH systems. For making the assessments quantifiable, specific case study DH network with a CHP plant as the main tool of supply is considered for the analyses. Three different design scenarios for the system are considered for all of which the results of the energy, exergy, and economic analyses are presented for the subsystems and the whole heat grid. Through thermoeconomic analysis, the unit exergy costs of electricity and heat and unit exergy costs of Space Heating (SH) and Domestic Hot Water (DHW) are determined. The results showed that lowering the operating temperatures increased the overall energetic and exergetic efficiencies of the CHP-supplied DH system, while reduced the cost per exergy unit associated with the SH and DHW supply. • Modelling of CHP plant and DH system with thermoeconomic principles. • Comparative assessment of different DH operational temperature levels. • Determination of exergy destruction and exergy destruction costs in DH system. • Quantification of the cost per exergy unit of SH and DHW heating exergy. [ABSTRACT FROM AUTHOR]

The four different piston-prop engines (PPE1, PPE2, PPE3, PPE4) are investigated along with thermodynamic (energy and exergy), thermoenvironmental (based on exergy), and thermoeconomic (economic, specific exergy cost [SPECO], exergy-cost-energy-mass [EXCEM], modified EXCEM [m-EXCEM]) analyses for Landing and Take-off (LTO) flight phases. Maximum power is generated by the engine in the take-off phase during flight time. The take-off phase is taken into account while comparing thermodynamic, thermoenvironmental and thermoeconomic performance metrics of engines since maximum fuel consumption happens and maximum engine power is realized in this phase. In this case, the specific fuel consumption, energy efficiency, exergy efficiency, environmental effect factor, ecological objective function, ecological impact points, specific product exergy cost, relative cost difference, exergoeconomic factor, waste exergy cost rate, EXCEM cost formation rate, and m-EXCEM cost formation rate of PPE3 are estimated to be 0.081 kg/MJ, 27.677%, 26.017%, 2.844, −1485.434 MJ/h, 2.897 mPts/MJ, 0.322 $/MJ, 430.263%, 33.908%, 139.120 $/h, 0.0141 MJ/h/$ and 2.453 MJ/$, respectively. The PPE3 is the best engine between the four different PPEs in the terms of thermodynamic efficiently, environmentally friendly, and cost-effective. • Four different piston prop engine are investigated for Landing and Take-Off Flight Phases. • Each engine is assessed by thermodynamic, thermoenvironmental and thermoeconomic analyses. • Performance metrics are obtained for each flight phases of each engine. • PPE3 engine has the best performance values for maximum power usage at Take-off flight mode. [ABSTRACT FROM AUTHOR]

Ground-source heat pumps are widely used around the world because of their capacity to provide renewable and emissions-free energy for residential use. A vertical ground-source heat pump in an air conditioner mode is studied experimentally and numerically. The geothermal heat pump is located in Mexico, and consists of a single U-tube of 100 m depth, with 41.16 m3 of conditioned space. A computational fluid dynamics analysis of the geothermal heat exchanger and a thermoeconomic analysis of the heat pump are developed to evaluate the thermal performance of the system under the weather conditions of Mexico, and to know the cost allocation per equipment of the system. Results show that the geothermal heat pump provides a comfort temperature with the minimum value of a comfort relative humidity; the most important temperature changes for the geothermal heat exchanger are present during the first 10 m depth; the system decreases its performance when operating in cities with hot ambient temperatures; the irreversibilities present in the system are small, and the cost of the components depends mainly on the capital investment. In addition, the coefficient of performance of the system is of 3.3–3.6. • A vertical ground-source geothermal heat pump is studied in Mexico. • Experimental, CFD, and thermoeconomic studies are developed for the heat pump. • The most important temperature changes of the soil are present during the first 10 m. • The HP provides a comfort temperature with the minimum of a comfort relative humidity. • The system's performance decreases when operating in hot ambient temperatures. [ABSTRACT FROM AUTHOR]

• Industrial CHP system driven by a micro gas turbine engine is investigated. • Thermoeconomic assessments of the system are done by SPECO and EXCEM methodologies. • EXCEM model is modified and applied to the investigated system. The natural gas fired combined heat and power system driven by a micro gas turbine engine (M−CHP) of a dairy products company is investigated basing on the actual test data. The system is investigated along with economic analysis and specific cost (SPECO), exergy-cost-energy-mass (EXCEM), modified EXCEM (m-EXCEM) thermoeconomic analyses. The present worth of M−CHP system is estimated to be 241,190.20 US$. According to SPECO method, the cost formation of waste exergy in the M−CHP system is found as 6.634 US$/h, while the combustion chamber component of the system has the maximum (worst) waste exergy cost rate to be 4.366 GJ/h. According to EXCEM method, the waste exergy cost formation of M−CHP system is determined to be 0.563x10-6 GJ/hUS$, while it is estimated as 0.078 GJ/US$ with m-EXCEM method. Among the components of the system, the combustion chamber has the worst waste exergy cost rate. [ABSTRACT FROM AUTHOR]

• Two innovative flared-intercooled sCO 2 power cycles (FPC1 and FPC2) are introduced. • Direct oxy-combustion technology is used to realize no flaring-no emissions target. • Energy, exergy, exergoeconomic, LCOE, and optimization analyses are conducted. • Investigating six flare gas samples differ in their composition and specifications. • A minimum LCOE of 5.02¢/kWh is achieved in FPC1 at thermal efficiency of 45.10%. With more than 150 billion m3 of gases annually flared around the world, gas flaring is a major source of greenhouse gas emissions that contaminates the environment with more than 400 Mt CO 2 /year. Therefore, utilizing the flared gases efficiently becomes inescapable and one of the most promising utilization technologies is using Gas-to-Power (GTP). However, most of the available GTP technologies are still using conventional power cycles that have limited efficiencies and produce high-level of emissions. Herein, we use direct oxy-combustion (DOC) supercritical CO 2 (sCO 2) power cycle, instead, to realize the desired no flaring-no emissions solution. Two innovative flared-intercooled sCO 2 power cycles that utilize flare gases and natural gas as fuel are introduced. In the first flared power cycle (FPC1), the flare gases are mixed with the natural gas before being combusted in the DOC. While in the second cycle (FPC2), the flare gases are used to perform a reheating process for the exhaust flow of the primary heater (DOC) after being partially expanded in a high-pressure turbine. Comprehensive energetic, exergetic, exergoeconomic, levelized cost of electricity (LCOE), and multi-objective optimization analyses are conducted for each configuration over practical ranges of operating conditions for six flare gas samples that significantly differ in their composition and specifications. A minimum LCOE of 5.02¢/kWh is achieved by sweet flare gas sample in FPC1 at T max of 731 °C, P max of 300 bar, P min of 40 bar, T min of 32 °C, and W ̇ net of 50 MW with energy efficiency of 45.10%. At the optimized conditions, FPC1 and FPC2 show superior energetic and economic performances compared to indirect-combustion power cycles, however, indirect combustion of flare gases may perform better than FPC2 at low capacities and therefore recommended for future work. [ABSTRACT FROM AUTHOR]

• A combined system based on the sCO 2 cycle is proposed for power generation. • An absorption heat transformer is employed to upgrade the sCO 2 cycle waste heat. • The regenerative effect of the sCO 2 cycle is enhanced in the proposed system. • The proposed system can improve thermodynamics and economy by 4.96% and 3.66%. This study aims to investigate the system performance enhancement brought by an absorption heat transformer (AHT) on the supercritical carbon dioxide (sCO 2) Brayton cycle. In the proposed sCO 2 /AHT system, the AHT cycle serves as a bottoming cycle to upgrade the energy level of the waste heat in the sCO 2 system, producing high-quality thermal energy output to preheat the CO 2 at the main compressor outlet. System performance is evaluated through the established and validated model. The variation trends of system performance with four key parameters are determined from the parametric analysis. Moreover, optimization and comparative analysis are performed for the sCO 2 system, sCO 2 /ORC system and sCO 2 /AHT system. The results suggest that the sCO 2 /AHT system shows the best system performance. The exergy efficiency of the proposed system is 64.013%, which is 4.96% and 1.87% higher than that of the sCO 2 system, sCO 2 /ORC system. The total product unit cost of the proposed system is 18.903$/GJ, which is 3.66% and 2.24% lower than that of the other two systems. Exergy analysis indicates that compared with the sCO 2 system, the proposed system can effectively reduce the exergy destructions in the pre-cooler (4.97 MW to 1.32 MW) and get a strengthened regeneration effect for the sCO 2 cycle. [ABSTRACT FROM AUTHOR]