Exergy Cost Research Articles

Innovative multi-generation system producing liquid hydrogen and oxygen: Thermo-economic analysis and optimization using machine learning optimization technique

This research investigates the multi-objective optimization of a geothermal-driven multi-generation system designed to produce liquid hydrogen and oxygen as its primary outputs. The system incorporates a Proton Exchange Membrane (PEM) Electrolyzer alongside a modified ejector-based Organic Rankine Cycle to generate the required Energy (heating bar, cooling bar, electricity and hydrogen). Case studies were conducted in three distinct locations: Zanjan in Iran, Aarhus in Denmark, and San Bernardino in the United States, utilizing actual geological and meteorological data for accuracy. Simulations were executed applied Engineering Equation Solver & optimization of the system was carried out to enhance performance by focusing on the objective functions of system exergy efficiency and cost reduction. This was accomplished by utilizing response surface methodology (RSM) along with Minitab software (MS).To optimize the system, six decision variables were identified as critical parameters influencing performance. The optimization results indicated that the system can achieve an exergy efficiency of 53.74 % while maintaining a cost rate of $31.56 per hour. The overall cost rate for the geothermal system was determined to be $54.50 per hour, with $10.10 per hour allocated to hydrogen production and $44.40 per hour to electricity generation. Site-specific analyses highlighted San Bernardino as the most favorable location for implementing this system, projecting an annual production of 90.8 tons of liquid hydrogen and 208.3 kg of oxygen. In August, the geothermal system in San Bernardino can produce up to 7691.6 kg/h of liquid hydrogen, while in December, production decreases to 7402.8 kg/h, marking the lowest output for the year. In contrast, Zanjan and Aarhus demonstrated lower production capacities, underscoring the system's feasibility as dependent on site-specific conditions.

Thermodynamic and exergo-economic evaluation of biomass-to-X system combined the chemical looping gasification and proton exchange membrane fuel cell

The resource utilization of biomass is of great significance to the adjustment of energy structure. The syngas produced by biomass gasification can be used for power generation and production of green chemical raw materials. In this paper, a biomass-to-X (BtX) system based on the chemical looping gasification and high temperature proton exchange membrane fuel cell (PEMFC) is proposed to produce methanol, electricity, heating and cooling. The heat produced by the BtX system is harnessed for the regeneration of the carbon capture solution, as well as to drive both the organic Rankine cycle and the double-effect absorption chiller, enabling cascade utilization of the energy. The thermodynamic and exergo-economic models are carried out to evaluate system performance. The relationship between the material, energy and cost flow from biomass to products is analyzed. Finally, the influence of key parameters on system performance is studied. The results show that the energy efficiency of the BtX system is 54.0 % and the exergy efficiency is 35.4 %. The yield rate of methanol with 99.2 wt% purity is 6.48 tons/h. The cost of equipment, propanol and biomass accounts for 34.9 %, 28.9 % and 28.1 % of the total investment cost, respectively, while the cost of the PEMFC stack represents 50.4 % of the equipment costs. The unit exergy cost of the electricity and methanol are 0.068 $/kWh and 0.049 $/kWh, respectively. The methanol, carbon capture and cooling costs are most sensitive to the change in the propanol cost, followed by the biomass cost. For every 0.05 increase in the hydrogen fraction to methanol production, the electricity decreases by 3.1 MW and the methanol yield increases by 0.23 kg/s.

Proposals for Next-Generation Eco-Friendly Non-Flammable Refrigerants for a −100 °C Semiconductor Etching Chiller Based on 4E (Energy, Exergy, Environmental, and Exergoeconomic) Analysis

Recent advancements in cryogenic etching, characterized by high aspect ratios and etching rates, address the growing demand for enhanced performance and reduced power consumption in electronics. To precisely maintain the temperature under high loads, the cascade mixed-refrigerant cycle (CMRC) is predominantly used. However, most refrigerants currently used in semiconductor cryogenic etching have high global warming potential (GWP). This study introduces a −100 °C chiller using a mixed refrigerant (MR) with a GWP of 150 or less, aiming to comply with stricter environmental standards and contribute to environmental preservation. The optimal configuration for the CMRC was determined based on a previously established methodology for selecting the best MR configuration. Comprehensive analyses—energy, exergy, environmental, and exergoeconomic—were conducted on the data obtained using Matlab simulations to evaluate the feasibility of replacing conventional refrigerants. The results reveal that using eco-friendly MRs increases the coefficient of performance by 52%, enabling a reduction in compressor size due to significantly decreased discharge volumes. The exergy analysis indicated a 16.41% improvement in efficiency and a substantial decrease in exergy destruction. The environmental analysis demonstrated that eco-friendly MRs could reduce carbon emissions by 60%. Economically, the evaporator and condenser accounted for over 70% of the total exergy costs in all cases, with a 52.44% reduction in exergy costs when using eco-friendly MRs. This study highlights the potential for eco-friendly refrigerants to be integrated into semiconductor cryogenic etching processes, responding effectively to environmental regulations in the cryogenic sector.

Applying Circular Thermoeconomics for Sustainable Metal Recovery in PCB Recycling

The momentum of the Fourth Industrial Revolution is driving increased demand for certain specific metals. These include copper, silver, gold, and platinum group metals (PGMs), which have important applications in renewable energies, green hydrogen, and electronic products. However, the continuous extraction of these metals is leading to a rapid decline in their ore grades and, consequently, increasing the environmental impact of extraction. Hence, obtaining metals from secondary sources, such as waste electrical and electronic equipment (WEEE), has become imperative for both environmental sustainability and ensuring their availability. To evaluate the sustainability of the process, this paper proposes using an exergy approach, which enables appropriate allocation among co-products, as well as the assessment of exergy losses and the use of non-renewable resources. As a case study, this paper analyzes the recycling process of waste printed circuit boards (PCBs) by disaggregating the exergy cost into renewable and non-renewable sources, employing different exergy-based cost allocation methods for the mentioned metals. It further considers the complete life cycle of metals using the Circular Thermoeconomics methodology. The results show that, when considering the entire life cycle, between 47% and 53% of the non-renewable exergy is destroyed during recycling. Therefore, delaying recycling as much as possible would be the most desirable option for minimizing the use of non-renewable resources.

Thermo-economic investigation and comparative multi-objective optimization of dual-pressure evaporation ORC using binary zeotropic mixtures as working fluids for geothermal energy application

This contribution performs an energy, exergy, and exergoeconomic (3E) analysis of a dual-pressure evaporation organic Rankine cycle system employing twenty different binary zeotropic mixtures as working fluids for power production from a geothermal field. To this end, the designed system is modeled, invoking the mass and energy conservation laws and the exergy and cost balance analyses. Specific Exergy Costing (SPECO) procedure is utilized to provide practical insights into the exergoeconomic aspect of the system. Comparative optimization based on the multi-objective genetic algorithm is accomplished for each mixture in order to simultaneously maximize the exergy efficiency and minimize the total cost rate using the design variables of pressure factor in low-pressure and high-pressure stages, mixture fraction, pinch point temperature differences in low-pressure and high-pressure heat exchangers, and degree of superheat in the high-pressure heat exchanger. In this regard, the Pareto frontiers are drawn for the system with all twenty different binary zeotropic mixtures. The optimal point for each mixture is obtained via the decision-making technique of LINMAP. Subsequently, the LINMAP is re-utilized to find the preferred mixture. The optimization results suggest the R123/C2Butene (96.89/3.11) mixture for this system as the optimum working fluid, considering a trade-off between a low-cost rate of $88.0651 per hr and a high exergy efficiency of 64.07 %. Finally, the exergy flow diagram is plotted to provide the exergy flow rate and the amount of exergy destruction in each segment of the system considering the optimal working fluid. In the proposed system, exergy destruction chiefly occurs within the low-pressure preheater with a value of 1061 kW, followed by the low-pressure turbine and condenser with magnitudes of about 669 kW and 266 kW, respectively.

Enhancing efficiency and economy of hydrogen-based integrated energy system: A green dispatch approach based on exergy analysis

Hydrogen-based integrated energy system holds promise for leveraging the low carbon advantage of hydrogen, but inefficiency of electrolysis hydrogen production leads to significant exergy loss within its operation. Addressing this, this paper focuses on the energy-saving and economic operation of the hydrogen-based integrated energy system, proposes a novel green dispatch approach using loss cost as the objective function and establishes a refined loss cost accounting model based on exergy analysis theory. Firstly, derived from the analogy of exergy loss, the concept and accounting framework of system loss cost are proposed. Secondly, employing exergy analysis and consistent unit exergy cost principle, equipment operation loss cost is calculated through energy, exergy flows analysis and cost allocation. Thirdly, utilizing the total of equipment operation loss cost, wind curtailment penalty cost, and transmission line loss cost as the objective function, a green dispatch model is formulated to minimize overall loss cost while ensuring energy balance and other constraints. Finally, simulations analysis are conducted. The results show that compared to economic dispatch, minimized exergy loss dispatch and multi-objective dispatch methods, proposed approach increases exergy efficiency by 0.54 %, reduces cost by 6.13 % and increases the scale of hydrogen utilization by 3.45 %, respectively.

A possible reconciliation between exergy analysis, thermo-economics and the resource cost of externalities

Goal of this paper is to highlight and place in a comprehensive historical perspective the consequential continuity between the first attempts to link the concept of monetary cost to thermodynamic principles and the latest developments that led to exergy-based cost indicators and Sustainability numeraires.This is an orientation paper, and a conscious effort was made to avoid presenting the advancements in the economic-thermodynamic paradigms by simply listing them in their chronological order: whenever possible, and on the basis of well-documented references, a “conceptual tree” is discussed that originates with the introduction of the exergy concept (the roots), grows through a trunk (cost formation theory, Techno-Economics) and main branches (Thermo-Economics, Cumulative Exergy Consumption …) and terminates with the latest exergy-based cost theories.In Section 2 a brief recap of the concept of “cost” is provided, to clarify the different physical bases and proxies adopted in different approaches. Sections 3 and 4 contain a brief historical outline of the path that led from the recognition that exergy is a proper valuation index for energy to the initial critique to Techno-Economics and to the formulation of Monetary Thermo-Economics and to some of its initial developments. Techno-Economics, Thermo-Economics (both monetary and purely exergy-based), and other paradigms that postulated a quantifiable correlation between exergy and production cost are discussed in sections 6 through 10. Every effort has been made to provide the most relevant references for each conceptual and practical statement reported in the paper: as a result, the Reference list has grown beyond the Journal page limit, and it is available as a separate file in the Additional Material.

Assessing PEM fuel cell performance in a geothermal Cogeneration system for peak-time energy storage

In this investigation, a novel geothermal power plant was designed, combining absorption chiller units, PEMFC, EPEM, and ORC. We conducted a comprehensive case study across four continents—Asia, Oceania, Europe, and America—leveraging weather data from various cities to evaluate the system's efficacy. Our modeling utilized EES (Engineering Equation Solver) software, optimizing the setup via the RSM with three key objective functions: exergy efficiency, hydrogen production, and cost rate. The primary focus was on delivering electricity to residential properties during peak demand periods. Exploring six scenarios for organic fluids in organic Rankine cycles, we gauged energy, exergy, and overall system performance. The TOPSIS method led us to select scenario 3, employing R123 and R134a refrigerants, as the optimal choice. The results of the optimization showcased impressive figures: an exergy efficiency of 81.816%, a hydrogen production rate of 25.119 kg/h, and a cost rate of 15.967 $/h for the system's most efficient configuration. Economic analysis highlighted the organic Rankine cycle units 1 and 2 as the components with the highest costs. Our evaluation extended to various cities—Aomori, Grosseto, Lhasa, Wellington, and San Diego—assessing the electricity, heating, and cooling needs of residential complexes based on the system's performance.

Optimization and exergoeconomic analyses of water-energy-carbon nexus in steel production: Integrating solar-biogas energy, wastewater treatment, and carbon capture

The steel industry is one of the hard-to-abate sectors for decarbonization, and direct electrification is not possible or economically infeasible. This study investigates the application of the Water-Energy-Carbon nexus in the steel industry through a multi-generation plant, addressing the industry's demands for water, energy, and alternative fuel. The proposed multi-generation plant consists of parabolic trough solar collectors, an organic Rankine cycle, urban wastewater treatment, carbon capture, anaerobic digestion combined with heat and power, a proton exchange membrane electrolyzer, and a steelmaking plant. Thermodynamic and exergoeconomic analyses are conducted to investigate the system's efficiency and economic performance. A sensitivity analysis is conducted to identify the optimal links between nexus resources, followed by a multi-dimensional evaluation and multi-objective optimization. The results showed that under base conditions, the plant can annually produce 900 ktons of steel, 105 GWh of net power, 430.1 tons of water, and 517 tons of hydrogen, while preventing 34.7 ktons of CO2 emissions. The exergy efficiency and unit exergy cost of the products are 46.1% and 57.8 $/GJ, respectively. Under optimized conditions, the plant achieves a maximum net annual power output of 160 GWh, an exergy efficiency of 46.9%, and a minimum unit exergy cost of 51.4 $/GJ.

Thermodynamic analysis of trigeneration system with controlled thermal-electric ratio by coupling liquefied natural gas cold energy and biomass partial gasification

Efficient utilization of biomass energy is crucial for addressing environmental challenges. However, the low calorific value of syngas from biomass gasification poses subsequent utilization issues. This study proposes a trigeneration system integrating biomass partial gasification and LNG cold energy to address surge problems using syngas combined cycle systems. The design includes air separation units, combined cycle, and biomass gasifier, achieving an adjustable thermal-electric ratio. An air separation unit and two-stage Organic Rankine Cycle fully utilize LNG cold energy. A thermodynamic model was established in Aspen Plus, and energy, exergy, and economic analyses were conducted to assess feasibility, followed by a sensitivity analysis. Results show that with a mix burning ratio and carbon conversion rate of 0.6 and 0.7, the system's exergy, energy, and electrical efficiencies are 36.94 %, 60.14 %, and 33.32 % in cooling mode. The unit exergy cost and CO2 emissions are 0.0748$ and 95.29 kg/s, respectively. Analysis reveals variations in efficiency and outputs with changes in mix burning ratio and carbon conversion rate. Adjusting operational parameters enhances the system's ability to regulate the thermal-electric ratio, demonstrating its potential for efficient biomass energy utilization and environmental sustainability.

Advanced exergoeconomic analysis and mathematical modelling of the natural gas fired gas turbine unit used for industrial cogeneration system

In this study, mathematical model of advanced exergoeconomic analysis (ADEXEC) basing on advanced specific exergy cost (ADSPECO) and advanced exergy-cost-energy-mass (EXCEM) (ADEXCEM) methods are applied to the industrial cogeneration system (COGEN) which consists of natural gas fired gas turbine unit (with combustion chamber (CC), turbine (GT) and air compressor (AC)), pipe line (PL), wall (WD) and ground (GD) tile dryers under the dead state conditions of 10 °C, 15 °C, 20 °C, 25 °C and 30 °C. According to ADSPECO analysis; although CC ($6.97/GJ) has the lowest unit fuel exergy cost among the components, it has the highest exergy destruction cost rate ($252,391/hour at 30 °C) due to its high exergy destruction value. Although more than 40 % of the exergy destruction cost rate in the COGEN system is detected in CC, WD (105.541 $/h at 30 °C) and GD (107.499 $/h at 30 °C) which together account for more than 67 % of COGEN's avoidable exergy destruction are understood to be the first components to focus on. The fact that the exergy destruction cost rates of all components except PL is higher than the exogenous part of the endogenous part at all dead state temperatures reveals the weakness of the relationship between the components.

Two-stage hydrothermal liquefaction of Spirulina: Experimental observations, energy analysis and techno-economic assessment

The intensification of environmental pollution and significant consumption of fossil fuels has led to widespread attention on developing renewable resources. As a carbon-containing renewable energy source, Spirulina is characterized by its fast growth cycle and wide distribution. Currently, one of the research hotspots is the conversion of Spirulina into bio-oil through hydrothermal liquefaction. However, studies on the two-stage hydrothermal liquefaction of Spirulina predominantly concentrate on the product yield or composition. There is relatively little research on thermodynamic (energy) analysis and techno-economic assessment during the reaction process. The main bio-oil components from two-stage hydrothermal liquefaction of Spirulina are ketones and acids with 44.9 % and 34.1 %, respectively. Compared to no-catalysis, two-stage hydrothermal liquefaction of Spirulina over HZSM-5, alkili-modified HZSM-5, and Ni@alkali-modified HZSM-5 increase the relative content of hydrocarbons to 6.6 %, 32.9 % and 48.1 %, respectively. Energy analysis and techno-economic assessment are conducted with Aspen Plus simulation, revealing a exergy efficiency of 56.4 % for the catalytic two-stage hydrothermal liquefaction of Spirulina compared with 43.6 % over no-catalyst. The primary losses occur in the first stage of the reaction process (248.6 kW) and the cooling process (10.7 kW) for catalytic two-stage hydrothermal liquefaction of Spirulina. The hourly price of producing 1 kg bio-oil with a catalyst is $3.67, while without a catalyst, it is $4.54 kg−1; obtaining a unit of chemical exergy costs $0.14×10−3 kJ−1 through catalysis. Moreover, the fluctuations in the prices of sulfuric acid and catalysts are most sensitive to the cost price of bio-oil with or without catalysts in the two-stage hydrothermal liquefaction process, with the values being 10.06 % and 8.10 %. This study has important significance for efficient transformation and energy utilization of Spirulina.

The future of thermoeconomics: From industrial cost minimization toward cumulative resources accounting and sustainability assessment

Thermoeconomics has been developed with the main object of first identifying, and then reducing the costs of the energy produced by industrial power plants. More recently, the same approach formalized in the Exergy Cost Theory has been recognized as a useful tool also in a wider field, like industrial symbiosis and sustainability assessment. To do this, exergy supply chains have been tracked backward and backward, to include in the primary resource consumption a more and more complete inventory of the indirect consumption.In the Authors’ opinion, the future of Thermoeconomics is to go on in this direction. If a very complete inventory of all indirect consumption were obtained, the sustainability assessment of a production process could be performed (at least in principle) by applying the idea that the lower its consumption (direct and indirect) of scarce primary resources, the more sustainable a production process is.In this paper, the idea of the Thermoeconomic Environment (TEE) is summarized, to highlight as it is a consistent ultimate boundary of the exergy cost accounting, where the origin of the exergy supply chains can be properly placed. Then, the frame of the TEE is used to discuss some possible options for obtaining a more complete inventory of all indirect consumption, and to outline its possible perspective connections with some relevant environmental models, coming from Biology, Dynamic of Populations, or Climatology.

Energy, exergy, exergoeconomic, economic, and environmental analyses and multi-objective optimization of a novel combined cooling and power system with dual-pressure Kalina cycle-absorption refrigeration

A novel combined cooling and power system, the dual-pressure Kalina cycle-absorption refrigeration (DPKC-AR-CCP), is proposed for the cascade utilization of waste heat from high-temperature flue gas and jacket water from internal combustion engines. A pneumatic booster pump unit is employed to increase the inlet pressure of the low-pressure expander, with heat generated during the compression process utilized for preheating the ammonia/water mixture, and exhaust gas from the low-pressure expander is combined with driving gas for absorption refrigeration. By integrating the first and second laws of thermodynamics with the SPECO Methodology, models for energy, exergy, exergoeconomy, economy, and environment of the DPKC-AR-CCP system are developed. A multi-objective optimization model is formulated with maximum exergy efficiency, minimum total exergy cost rate, and maximum annual equivalent carbon dioxide (CO2) emission reduction as objective functions. MATLAB software (combined with REFPROP software) is utilized for simulation and multi-objective optimization. The performance of each component under specific conditions is assessed, and a comparison with the simple absorption refrigeration/Kalina cogeneration system (AR/KC) highlights the advantages of the DPKC-AR-CCP system; an investigation into the effects of different operating parameters on performance is conducted. The results indicate that, under identical operational parameters, the DPKC-AR-CCP system exhibits a substantial increase in net output power (230.2 %), cooling capacity (98.7 %), and exergy efficiency (148.8 %) compared to the simple AR/KC system; payback period is reduced by 64.8 %; and annual equivalent CO2 emissions are decreased by 202.2 %. However, there is an increase in the total exergy cost rate by 90.5 %. The optimal concentration of ammonia/water is determined to be 0.816/0.184, with a heat exchanger outlet temperature of 341.07 K, driving pressure of 0.654 MPa, and low-pressure expander inlet pressure of 5.064 MPa. Correspondingly, the optimal exergy efficiency is 87.2 %, the annual reduction in CO2 emissions is 5.53 × 107 kg, and the total exergy cost rate is 288.48$/h.

A novel exergy-based cost and carbon footprint allocation method in the multi-energy complementary system

Energy efficiency, economic cost and carbon emission of multi-energy complementary systems are three key indicators to sustainable development in the low-carbon background. This paper analyzes the coupling relationships between energy, cost, and carbon emission flows in a combined cooling, heating, and power (CCHP) system. The CCHP system consists of biomass gasification, co-firing internal combustion engine by product gas and natural gas, concentrated photovoltaic thermal solar collector, and absorption heat pump. A novel exergo-carbon method with exergo-economic analyses is proposed to determine the exergy cost and carbon footprint rate of each stream in the CCHP system, and the unit cost and carbon footprint of multiple products of electricity, cold energy and heat energy are obtained by the proposed method. The impacts of co-firing ratio and photovoltaic coverage ratio on energy and exergy efficiencies and cost and carbon footprint of products are analyzed. The sensitivity of biomass carbon footprint is performed to show its influences. The total cost of products including economic and carbon costs, is discussed to guide the carbon market's pricing strategies. Under the design conditions, the unit exergy cost of electricity, chilled water and hot water are 0.1094, 0.7659 and 0.466 $ (kWh exergy)−1, and their unit exergy carbon footprints are 0.3651, 3.9050, and 2.3780 kg CO2-eq (kWh exergy)−1, respectively.

Thermoeconomic assessment of the air-cooled tropical data center through energy-saving strategies

Rapid developments in the electronic information industry drive the increased energy usage and carbon emission of data center buildings, prompting the focus on the energy efficiency and environmental sustainability. Expanded operation envelopes of tropical data centers is assessed to analyze the potential for the building energy savings and carbon emission reduction through collaborative analysis of operation modes (OMs), supply air temperature (SAT), and outdoor air temperature (OAT). The OMs of compression vary with the setpoints of SAT, in which the average exergy efficiency of compressors at alternate operation mode is 6.8 % and 8.0 % lower than that of double and single compression operations. As SAT rises from 20 °C to 32 °C, the system exergoeconomic factor increases from 5.4 % to 8.0 %, and the average carbon cost decreases by 36.5 %. Additionally, with just an 8.5 % increase in exergy cost (i.e., Case 8) at OAT rising from 30 to 34 °C, the high SAT and low refrigerant charges provide considerable exergy cost advantages versus resisting the OAT fluctuations. Dynamic operation strategies are also proposed and compared to cope with the impacts of tropical environments. Compared to the 26 °C SAT baseline, the average energy savings are 9.1–14.7 %, indicating the ability to fully utilize outdoor and indoor conditions.

Thermoeconomic analysis of the IWERS system for steam heat recovery from bakery ovens

AbstractThe integrated waste energy recovery system (IWERS) recovers heat from bakery ovens in supermarkets and other commercial facilities to heat domestic hot water, resulting in energy savings. This article presents a thermoeconomic analysis of the system's operation in a supermarket over the course of 1 year. The study shows that exergy destruction in IWERS is directly proportional to ambient temperature. During the hottest months of the year, IWERS experiences a 4% decrease in exergy performance, while the exergy unit cost of the product increases by up to 4.2%. Additionally, the steam condenser is responsible for the highest relative exergy destruction, reaching almost 45%. Moreover, the addition of equipment upstream of the process increases the exergy cost of production due to the destruction of exergy in the equipment. These results provide valuable information with important implications for energy efficiency, economic savings, and sustainability. Improving system efficiency would generate substantial benefits in energy savings, economic savings, and environmental impact for all commercial and industrial establishments that use bakery ovens.

Exergoeconomic Analysis and Optimization of a Biomass Integrated Gasification Combined Cycle Based on Externally Fired Gas Turbine, Steam Rankine Cycle, Organic Rankine Cycle, and Absorption Refrigeration Cycle.

Adopting biomass energy as an alternative to fossil fuels for electricity production presents a viable strategy to address the prevailing energy deficits and environmental concerns, although it faces challenges related to suboptimal energy efficiency levels. This study introduces a novel combined cooling and power (CCP) system, incorporating an externally fired gas turbine (EFGT), steam Rankine cycle (SRC), absorption refrigeration cycle (ARC), and organic Rankine cycle (ORC), aimed at boosting the efficiency of biomass integrated gasification combined cycle systems. Through the development of mathematical models, this research evaluates the system's performance from both thermodynamic and exergoeconomic perspectives. Results show that the system could achieve the thermal efficiency, exergy efficiency, and levelized cost of exergy (LCOE) of 70.67%, 39.13%, and 11.67 USD/GJ, respectively. The analysis identifies the combustion chamber of the EFGT as the component with the highest rate of exergy destruction. Further analysis on parameters indicates that improvements in thermodynamic performance are achievable with increased air compressor pressure ratio and gas turbine inlet temperature, or reduced pinch point temperature difference, while the LCOE can be minimized through adjustments in these parameters. Optimized operation conditions demonstrate a potential 5.7% reduction in LCOE at the expense of a 2.5% decrease in exergy efficiency when compared to the baseline scenario.

Techno-economic analysis and dynamic performance evaluation of an integrated green concept based on concentrating solar power and a transportable heat pipe-cooled nuclear reactor

The nuclear-solar hybrid system (NSHS) is regarded as a promising solution to meet the growing energy requirements of remote areas. Currently, design schemes and parametric analyses for small-scale application scenarios are still limited. This study has proposed an innovative transportable micro heat-pipe cooled nuclear reactor (HPR) coupled with a concentrating solar power (CSP) system to achieve flexible load regulation. First, a dynamic simulation model for the NSHS is established in the Simulink platform, considering turbomachine off-design characteristics and the power-load matching dispatch principle. Then, techno-economic analyses are carried out to explore the exergy and capital cost flow processes. The results reveal that the NSHS shows clear seasonal features with the highest load cover rate of 98.31 % in summer and the lowest of 73.82 % in winter. The total exergy effectiveness of the NSHS is 29.4 %, with an average electricity cover ratio of 88.67 % and a solar energy penetration ratio of 13.32 %. The calculated LCOE is 80.84 $/MWh, and the payback period is 3.62 years. The life cycle emission of the system is assessed as 10.23 g CO2 eq./kWh. Compared with the solar standalone system, the hybrid system with higher efficiency faces challenges in high-temperature resistance and thermal insulation.

4E analysis of a solar, wind and waste heat-driven CCHP system: A case study for a cruise ship

One of the most advanced technologies for meeting all cooling, heating, and electrical demands is Combined Cooling Heating and Power (CCHP) systems. This paper proposes using PV panels, wind turbines, and CCHP system based on an Organic Rankine Cycle integrated absorption chiller, for a cruise ship MS Birka Stockholm. A part of the electricity demand is provided by three wind turbines and PV panels, and another part is generated by the CCHP system. The proposed CCHP system works by recovering heat by three main engines in summer and mid-season and four main engines in winter. It’s important to mention that in actual condition the ship is working with eight engines. Decreasing the number of engines and using renewable energies could be a very alluring issue in the transportation systems. Energy, Exergy, Exergoeconomic, and exergoenvironmental (4E) analysis is done for the system and also components with the highest exergy destruction and cost rate and environmental effects are recognized. 4E analysis could give the researchers opportunity to compare their proposed systems results, that is never done in this field. Mentioned analysis are divided into three parts, including winter, mid-season and summer. For the summer, energy and exergy efficiencies are 65% and 40.13%, respectively. The coefficient of performance (COP) is also calculated 0.706. For mid-season, thermal efficiency is calculated 97.4% and exergy efficiency is calculated 24.31%. Therefore, for winter thermal efficiency is calculated 98% and exergy efficiency is calculated 9.3%. The cost associated with total exergy destruction is 1,193,099 €/year, and the total investment cost of the system is 179,592 €/year. The total environmental impacts associated with the exergy destruction and the total value of the component-related environmental impact of the system (Ẏ) were calculated as 2,479,713 mpts/year and 864,627mpts/year, respectively.