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Energy demand is a critical contemporary concern, with significant implications for the future. While exploring renewable or sustainable energy sources offers potential solutions, optimizing energy consumption in existing power generation systems is also key. Aviation accounts for a substantial portion of energy demand, underscoring the importance of energy efficiency in this sector. Conventional energy analyses may be misleading; hence, employing exergy-based analyses provides a clearer understanding of energy consumption. Also, most of these analyses do not include the effect of the turbine blade's cooling in calculations. In the present study, exergy analyses have been conducted on a helicopter turboshaft engine with turbine-blades cooling, focusing on design parameters such as ambient temperature, compressor pressure ratio, and turbine inlet temperature. Thermodynamic optimizations are conducted using a genetic algorithm. Results show that increasing pressure ratio and turbine inlet temperature boost performance, yet technical restrictions on compressor and turbine size, and metallurgical constraints on turbine blades' material limit these gains. Sea level scenario prioritizes ambient temperature-drop for enhancing net-work and efficiency, while altitude-gain boosts turboshaft performance. Combustion chambers incur the highest exergy destruction of 74-80%, followed by 16-20% and 4-6%exergy destructions in the turbine and compressor, respectively. Lower air temperatures and higher flight altitudes demand larger fuel consumption for equivalent turbine inlet temperature, albeit enhancing cooling capacity and reducing required cooling air fraction for turbine blades. [ABSTRACT FROM AUTHOR]

This study aims to assess and examine the gas turbine power generating system at the Qayyarah gas station in Nineveh City, Iraq. The evaluation conducted under real weather conditions for the year 2023. The gas turbine unit has a maximum load output capacity estimated at 125 megawatts. The system comprises a gas turbine, an air compressor, and a generator, all coupled by a shared shaft. Its functions based on a straightforward Joule-Brayton cycle. An analysis of the energy and exergy of the previously mentioned unit, taking into account the principles of conservation of mass, the first law, and the second law. The study specifically focused on examining the impact of several elements, including ambient temperature, compression ratio, relative humidity, and operational load. Two techniques used to replicate company data: the first approach included scripting the simulation using Excel, while the alternative option utilized Aspen HYSYS. The performance of the gas unit evaluated using the average data from each month of the simulation for that year. The simulation findings indicated that the combustion chamber is the primary component responsible for energy dissipation, and the highest energy yield may be achieved from fuel in the form of chemicals. The results of both approaches demonstrated that the maximum energy and energy efficiency achieved around 40.23% and 31.76%, respectively. [ABSTRACT FROM AUTHOR]

The process of phasing out of medium and high global warming potential refrigerants is accelerating in all areas of refrigeration, particularly since the European F-Gas Regulation No. 517/2014 and the ensuing Kigali amendment went into effect. Hydrocarbon refrigerants are being considered as suitable alternatives due to their low global warming potential and excellent thermal properties, but due to their flammability, safety precautions must be followed. This theoretical study contributes to the evaluation of the thermal and environmental impact of hydrocarbon refrigerants as drop-in alternatives to R134a in domestic refrigerator. In order to conduct an analysis of energy, exergy, and environmental factors, R134a and all hydrocarbons refrigerants proposed by ASHRAE--R290, R600, R600a, R601, R601a, and R1270--were examined as operating fluids used in a domestic refrigerator with a cooling capacity of 157 W and constant condenser temperature of 40°C and variable evaporator temperature every 5°C between -5 and -30°C. The results revealed that all the alternative refrigerants except R601 and R601a have higher thermal and environmental performance than R134a and can be used after refrigerator compressor replacement. [ABSTRACT FROM AUTHOR]

The search for environmentally friendly refrigerants for vapor compression systems has been a significant focus recently due to environmental concerns such as ozone depletion and global warming. In this study, the potential of R1224yd as an alternative refrigerant is investigated. A thermodynamic analysis of a 4-kW air conditioning system is conducted to assess the performance of R1224yd. The system is analyzed from a thermodynamic perspective, and key performance indicators such as the Coefficient of Performance and exergy efficiency. The results are then compared to R245fa and R123. Furthermore, a parametric study is performed to examine the impact of key parameters, such as evaporating and condensing temperatures, on the system's performance. This analysis provides insights into the sensitivity of the system's performance to variations in these parameters. The results indicate that R1224yd is a promising candidate as an environmentally friendly alternative refrigerant compared to R123 and R245fa. Because R1224yd has the lowest environmental impact. It has about 700 kg CO2 indirect emission, but about zero kgCO2 for direct emission. While, based on the thermodynamic results, R1224yd offers better performance compared to R245fa which has 1-3% higher in performance value and exergy efficiency, and has comparable performance to R123. This suggests that R1224yd can be a viable option for the systems, providing improved energy efficiency and lower environmental impact. [ABSTRACT FROM AUTHOR]

Power production, as well as transportation, are two sectors mainly contributing to global warming and pollution. These effects can be lessened through the use of biofuels. However, biofuels are plagued due to low calorific value and high viscosity compared to diesel. However, this can be overcome by proper adjustment of the operating parameters (Compression ratio, Fuel injection timing, Fuel injection Pressure, Engine load). The present study tries to unravel the influence of fuel injection pressure on the performance, combustion, emission, and exergy analysis of the Nahar biodiesel run diesel engine. Five fuel injection pressure (200 bar, 220 bar, 240 bar, 260 bar, 280 bar) and five engine loading conditions (20 %, 40 %, 60 %, 80 %, 100 %) at injection timing of 23° BTDC and compression ratio of 17.5 are considered. The results indicate that the performance, combustion, emission, and exergy parameters improve with the use of higher fuel injection pressure. The maximum BTEs are found to be 24.86 %, 27 %, 28.11 %, 29.22 %, and 31.13 % in biodiesel mode at FIPs of 200 bar, 220 bar, 240 bar, 260 bar, and 280 bar, respectively in comparison to 27.76 % for diesel at standard settings (FIP = 200 bar, CR = 17.5, IT = 23° BTDC) at 100 % load. Furthermore, the effect of addition of nanoparticles and variation of other operating parameters such as injection timing and compression ratio of the engine may enhance the performance and emissions of Nahar biodiesel run diesel engine. [ABSTRACT FROM AUTHOR]

The energy and exergy evaluation of simple gas turbine (SGT), gas turbine with air bottoming cycle (GT-ABC), and partial oxidation gas turbine (POGT) are studied. The governing equations for each cycle are solved using energy equation Solver (EES) software. The characteristics performance for selected cycles are discussed and verified with that obtained for available practical cycles (SGT, GT-ABC, POGT). The present results show a good agreement with the practical one. The effects of significant operational parameters, turbine inlet temperature (TIT), compression ratio (CR), and compressor inlet temperature (CIT), on the specific fuel consumption, energy and exergy efficiencies are discussed. According to the findings, a reduction in CIT and a rise in TIT and CR led to enhance energy and exergy efficiency for each configuration with different ranges. Results revealed that the GT-ABC and POGT cycles are more efficient than those of SGT at the same operational parameters. The energy and exergy efficiencies are 38.4%, 36.2% for SGT, 40%, 37.8 % for GT-ABC, and 41.6%, 39.3% for POGT. The POGT cycle has a better energy and exergy performance at a lower pressure ratio than the SGT and GT-ABC. [ABSTRACT FROM AUTHOR]

Increasing heating performance and preservation of product quality are critical factors in the food industry. Although microwave-vacuum heating is applied in many food processes, there are many unanswered questions about its effects on sensitive foods. In this study, the tomato juice was concentrated in microwave-vacuum heating system and results compared with conventional and conventional-vacuum heating methods. The effect of pressure and microwave power was investigated on quality parameters, energy consumption, exergy performance, and processing kinetics of tomato juice concentration. The processing time in the microwave-vacuum method was 2.3 to 6.3-fold lower than conventional and conventional-vacuum methods. The exergy performance was obtained in the range of 7.16–13.29% for microwave-vacuum heating and 2.04–2.99% for conventional methods. Microwave vacuum heating could reduce energy consumption by 30–71%, compared with conventional-vacuum methods. The minimum decline in ascorbic acid and total phenol content of tomato juice concentrate was observed for microwave-vacuum evaporation. Microwave-vacuum heating was an excellent concentration technique that provided tomato paste with improved nutritional quality, increasing exergy efficiency, reducing processing time and energy consumption compared to conventional and conventional vacuum processes. [ABSTRACT FROM AUTHOR]

Knowing that from 2030 refrigerants used in refrigerating engineering should have a global warming potential (GWP) of less than 150. Searching for eco-friendly refrigerants with good performance and minimal environmental impact to substitute conventional working fluids such as R134a (GWP=1430) represents a great challenge for researchers. The present research aims to investigate and compare the performances of the eco-friendly refrigerant R13I1 (Zero GWP) used as a possible new working fluid in the ejector-expansion refrigeration cycle (EERC) with the commonly used R134a which has good performances but a high GWP. To reach this objective, a numerical program was developed using MATLAB software to evaluate the coefficient of performance (COP), the entrainment ratio (µ), the exergy destruction and the exergy efficiency for both refrigerants. Furthermore, the effect of the diffuser efficiency of the ejector on the COP and the compressor work was explored. Furthermore, the effect of the diffuser efficiency of the ejector on the COP, and the compressor work were explored. The simulation was realized for Tc selected between 30 and 55 °C and Te ranging between -10 and 10 °C. Results proved that the use of R13I1 as a working fluid in the EERC system exhibited a higher COP, µ, and exergy efficiency, as well as lower exergy destruction compared with R134a under the same operating temperatures. On another hand, the energetic analysis revealed that as Tc increases the COP and µ decrease. However, as Te varies from -10 and 10 °C, the COP and µ increase. Regarding exergy analysis, it should be noted that both exergy destruction and exergy efficiency are sensitively influenced by Tc more than Te. Overall, the study confirms that R13I1 could be a suitable substitute for the phase-out R134a in terms of performance and environmental protection. [ABSTRACT FROM AUTHOR]

In this paper, new cycle is developed to generate simultaneously electrical and cooling power by placing a turbine between the generator and ejector in the conventional ejector-assisted absorption cooling cycle. The aim of developed cycle is to increase the exergy efficiency of cycle by adding an electrical power generation made it more environmentally friendly and reduce its dependents of fossil energy sources. The first, second laws of thermodynamic, mass and energy balance is applied for each cycle component and the constant mixing pressure ejector model is used to develop a numerical model of proposed cycle. The results depict that the augmentation of generation temperature is positively affected the work produced in the turbine contrary for cycle coefficient of performance, for every working conditions there are a certain value of generation temperature which its exergy performance of cycle achieves the maximum, the augmentation of output pressure of turbine is positively affected the cycle coefficient of performance contrary of the work produced in the turbine and the cycle exergy efficiency and the augmentation of condensation temperature is positively affected the cycle exergy efficiency and the work produced in the turbine contrary for cycle coefficient of performance and the augmentation of evaporation temperature is positively affected the cycle coefficient of performance and the cycle exergy efficiency contrary for the work produced in the turbine The results also show that the improvement of exergy efficiency of proposed cycle is 29.41% and 46% compared with the absorption cooling cycle with double and triple effect under the same operating conditions. [ABSTRACT FROM AUTHOR]

• Carbon dioxide capture and mitigation are key to the technological response to combat climate change and reduce CO 2 emissions. • Proposal of a novel system for performance improvement of the conventional post-combustion process. • Thermodynamic, economic, and environmental analyses of the proposed cycles. • The desorption column has the largest contribution to the exergy destruction 257.48 k W. • The solvent regeneration energy decreases to 2.77 G J / t C O 2 , 20.17 % lower compared to the conventional system. An optimum process with a novel method for improving the thermodynamic efficiency of the conventional post-combustion process based on a mono-ethanolamine (MEA) 30 wt% solvent is presented. The presented process, by preheating the rich solvent stream twice and using lean vapor compression (LVC), causes the solvent regeneration energy (E regen) to decrease, the exergy efficiency of the desorption column to increase, and the net CO 2 emission to diminish. According to the simulation results, the solvent regeneration energy in the base process is 3.47 GJ/t CO2 and has a value of 2.77 GJ/t CO2 in the proposed scheme, which exhibits a 20.17% decrease. The exergy analysis showed that the desorption column contributes the most to the exergy destruction in the post-combustion process. According to the performed analysis, in the proposed scheme, the exergy destruction in the desorption column reduces from 476.67 kW to 257.48 kW, which shows a 45.98% decrease. Under these conditions, the exergy efficiency of the desorption column is improved by 12.2%. Comparing E r e g e n parameter with that of previous studies demonstrated that the proposed scheme in this paper has significant superiority regarding optimizing the reboiler's energy. Due to the addition of a compressor, heat exchanger, expansion valve, and separator, the annual capital expenditure (CAPEX y) of the proposed scheme is 13.71% higher than the conventional process, which results in a 12.5% increase in the cost of CO 2 capture ( C o s t C O 2 , c a p t u r e ). [ABSTRACT FROM AUTHOR]

Thermodynamics studies the nature of energy and its forms of existence and transmission between systems. Exergy, as part of the Thermodynamics program in Chemical Engineering, plays a fundamental role in the development and promotion of processes related to energy saving. However, an analysis of the programs of Thermodynamics and related subjects for the Chemical Engineering degree in many Argentine universities revealed that there are few programs that include exergy as a component part of a Thermodynamics taught course, and those that do often use the few textbooks that address the subject. In this sense, a total of 92 textbooks have been counted as bibliography for the teaching of Thermodynamics/Physical Chemistry in Chemical Engineering. Out of that total, 39 books appear in at least two course programs, while the remaining 53 are less known books, and are cited by only one program. Of the 39 most widely used books, only 14 include the topic of exergy. On the other hand, the statistics of grades obtained by students in Thermodynamics indicate a low performance in the understanding of exergy. The results of exams showed deficiencies in different theoretical aspects related to the understanding of the topic with percentages of failure of 60%, 47% and 21% in three different evaluation instances. Moreover, the total percentage of students who could not solve the exergy problems or solved it with errors was significantly higher (> 67%) than the percentage of those who managed to solve it correctly (< 20%). In this work, a pedagogical proposal for the teaching of Exergy was formulated, contemplating the learning axes of the theoretical framework, the language and the nature of Thermodynamics. It is intended that this proposal serves teachers to promote a meaningful learning of exergy for Chemical Engineering students. • The multiplicity of historical definitions of exergy were discussed. • A proposal for teaching exergy is presented based on the meaningful learning theory. • A new procedure for deriving exergy expressions of closed and open systems was developed. • Differences between lost work, irreversibility and destroyed exergy were discussed. • Exergetic efficiencies for process equipment were defined and calculated. [ABSTRACT FROM AUTHOR]

A thermodynamic, economic and environmental analysis of a regasification system including a simple Organic Rankine Cycle (ORC) and an Open Organic Rankine Cycle (OC) to utilise the liquefied natural gas (LNG) cold energy is carried out in the present paper. The proposed system, called ORC-OC, uses ambient seawater as heat source (open loop) and is implemented on board a Floating Storage Regasification Unit (FSRU) in order to reduce the greenhouse gas (GHG) emissions associated with the electricity generation plant, i.e., dual fuel (DF) engines. Regarding the ORC working fluids analysed, an ethane/propane zeotropic mixture is applied. The ORC-OC is compared with the simple ORC architecture, giving the first one better energy (lower specific energy consumption), exergy (higher exergy efficiency) and environmental (lower CO2e emissions) results. When compared to the regasification systems installed on board, the ORC-OC system reduces the specific energy consumption by 86.99 % and increases the exergy efficiency by 17.82 % with respect to the most efficient conventional system installed on FSRUs (direct seawater regasification system), leading to a reduction of CO2e emissions of more than 80 %. In addition, the ORC-OC system is more costeffective than conventional regasification systems when the LNG price is above 6,508 USD/MMBtu. [ABSTRACT FROM AUTHOR]

Economic crises face a new foe worldwide, along with the fact that the Kingdom of Saudi Arabia (KSA) is facing problems to sustain its role in international energy prospects due to unavoidable domestic challenges caused by a fast-growing population. The challenges are unemployment for the youngsters, two-thirds of the total population, and emerging demand for energy consumption at the domestic level at unsustainably high rates. Besides this, KSA spends a considerable amount, around 9% of the GDP, to subsidize the energy sectors (oil products and electricity). All these aspects call for a selective study to pinpoint the factors which can directly or indirectly influence to sustain the Saudi economy in the long run. To help cater to the growing demand for rigorous study on areas for energy rationalization in the Qassim region, the objectives of this work are to perform a thorough study of energy and exergy analysis of various electrical household appliances and exergy analysis of the residential sector (RS). In this study, an independent survey of 100 dwellings was conducted to collect data related to essential parameters of residential energy consumption. The collected data has been analyzed to determine energy consumption indicators and perform exergy analysis. The average monthly and yearly energy consumption per dwelling was between 30,832 to 36,166, and 1500 to 4500kWh, respectively. The average hourly electrical energy consumption during the working days was 4.12kWh, and during the curfew due to the Coronavirus (COVID-19) 4kWh. The breakdown of this end-use of residential energy is mainly distributed for air conditioning, water heating, lighting, and all other domestic appliances with 67.34%, 9.31%, 8.18%, and 15.17%, respectively. The calculated total energy efficiency of 142.9% for KSA in this study showed a significant discrepancy compared to the previously reported value of 77.52%. Calculated total exergy efficiency falls between 11.13% and 11.38% for the Qassim region. Energy policymakers can use clear energy consumption indicators and exergy efficiency present in this study. They can help to establish energy efficiency standards to be used for various economic sectors. [ABSTRACT FROM AUTHOR]

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Developing countries are severely affected by water scarcity. To meet the growing demand for clean drinking water, minimal, small-scale methods that don't use much energy are needed. Saline water desalination utilising the solar still, which depends only on solar radiation, is a realistic option for rural coastal communities. The current research focuses on increasing the daily production of solar still distillate yield. This paper provides a modified design that incorporates an air cavity connected to a solar still absorber plate and an effort to calculate the solar stills technological and economic assessment. The current study extensively focuses on the usefulness of an air cavity in improving solar still performance under diverse climatic conditions. The experimentation was performed at varying depths of saline water in two different material solar stills. During the experimentation, the maximum saline water temperature observed was 89°C and the lowest temperature was found as 29 °C. Aluminium and polycarbonate stills had an average energy and exergy efficiency of 48.8 %, 3.44 %, and 42.4 %, 2.3 %, respectively. The daily yields for aluminium and polycarbonate stills were 2.8 to 3.8 l/m2/day and 1.8 to 3.4 l/m2/day, respectively. The cost per litre of the distillate from aluminium and polycarbonate stills was determined to be Rs. 0.723 and Rs. 1.361, respectively, with a payback time of 10 and 11 months. Overall, at 1.8 cm saline water depth, the aluminium still provides improved distillate yield than the polycarbonate still, and the addition of air cavity reprises in the improvement of the efficiency of the solar still. From the experimental findings of both the solar stills, we can conclude that they are long-term viable and cost-effective in producing more distillate than expected with a short payback time. [Display omitted] • A novel solar still design with an air cavity coupled to the absorber plate has been investigated. • Aluminium still yielded more distillate than polycarbonate still. • The average energy and exergy efficiency of aluminium stills were found to be 48.8 % and 3.44 %, respectively. • The cost per litre of distillate and payback time is calculated for two life expectancies of 12 and 15 years. • The cost per litre and payback period are Rs. 0.723/− and 10 months, respectively. [ABSTRACT FROM AUTHOR]

• A novel system is developed for a sustainable airport for hydrogen and kerosene production. • The primary focus of this study involves geothermal, biomass, and PV solar as energy sources. • The performance is evaluated using thermodynamic approaches and Aspen Plus modeling. • The study finds the performance of the system is greatly impacted by the variation in PV solar. • The kerosene production rate increases with an increase in the carbon monoxide to hydrogen ratio. The advancement of sustainable solutions through renewable and clean energy sources is considered crucial to mitigate carbon emissions. This study reports a novel system developed for an airport utilizing geothermal, biomass, and PV solar energy sources. The proposed system is capable of producing five useful outputs, including electrical power, hot water, hydrogen, kerosene, and space heating. The system proposed in the study is further considered for the Vancouver Airport in British Columbia, Canada using the most recent available data. The geothermal sub-system introduced in this study is also unique, which utilizes the carbon dioxide captured from biomass gassification as the heat transfer medium for geothermal heat to the Rankine cycle for power generation and heating. The present system is modeled and analyzed using thermodynamic method through energetic and exergetic approaches to determine the variation in system performance based on different annual environmental conditions. The biomass gasification and kerosene production are evaluated based on the Aspen Plus models and simulation. The efficiencies of the geothermal system with the carbon dioxide reservoir are found to have energetic and exergetic efficiencies of 78% and 37% respectively. The total hydrogen production is potentially estimated to be 452 tons on an annual basis. The kerosene production mass flow rate is reported as 0.112 kg/s. The overall energetic and exergetic efficiencies of the system are found to be 41.8% and 32.9% respectively. Moreover, this study offers crucial information for the aviation sector to adopt sustainable solutions more effectively. [ABSTRACT FROM AUTHOR]

• The CLC and cyclic CO2 were integrated to form a high-efficient syngas production and generating system. • The CLC CCR system achieved exergy efficiency of 55.02%, an improvement of 2.55 percentage points over the CCR system. • The cost of liquid fuel production was reduced by 9.21% compared to CCR system. • The extremely improvement potential in terms of energy savings and carbon emissions owned to CLC CCR. The utilization of greenhouse gases, such as CO 2 and CH 4 , as feedstocks for the production of synthetic fuels and chemicals has gained noteworthy traction. Converting syngas produced by carbon dioxide and methane into liquid fuel through Fischer-Tropsch synthesis is important method to address domestic oil shortage. However, the significant difference between the reforming and the combustion drive temperature can result in an energy level mismatch. Chemical looping combustion technology utilizes oxygen carriers to achieve graded utilization of energy, thereby reducing the irreversible losses in the conventional combustion process. This study conducted comprehensive thermodynamic and economic analysis of the chemical looping combustion coupled with methane carbon dioxide reforming (CLC CCR) process compared to the conventional process (CCR). The results demonstrate that the CLC CCR system has higher efficiency of 53.10% compared to 50.69% in the CCR system, leading to 9.21% decrease in production costs for liquid fuel. Additionally, the CLC CCR system increased liquid fuel output by approximately 5%, achieving impressive energy saving rate of 7.74% and significant reduction in carbon dioxide emissions by 21.51%. Furthermore, the efficiencies and economic performance were introduced to the study, and optimization measures were proposed to improve the efficiency and economic outcomes benefits of the main components. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigates power conversion efficiency and exergy of a gridconnected photovoltaic (PV) power plant by comparing solar exergy models at a time interval of 12 months. Statistical analysis was carried out to evaluate the PV exergy efficiency related to solar exergy models. First, solar exergy models proposed by Petela, Spanner, and Parrott and the mean of solar exergy-to-solar radiation energy ratio were calculated, and the PV exergy efficiency was analyzed. The results indicate that the average solar exergy-to-solar radiation energy ratio for the Samsun region was 0.93 related to Petela and Spanner's model. The ratio for Parrott's model was calculated as 0.99. The results confirm that the power conversion efficiency is in the range of 6.15-8.87%. While the PV exergy efficiency related to Parrott's model is seen to vary between 4.85% and 7.09% during 12 months, it changes from 5.19% to 7.60% in Petela and Spanner's model. [ABSTRACT FROM AUTHOR]

• Validated simulation model for a new compination air conditioning systems were presented. • Two different integration cases were presented according to the air condtioning system used. • Energy and Exergy analysis of new compination systems were studied under two different climates. • A reduction in CO 2 emissions was observed when using the proposed ssystems. This paper introduces novel modification for conventional air conditioning systems through utilizing a thermal ice storage system integrated with solar panels. Alexandria and Aswan, cities in Egypt, are chosen to represent two climates for hot-humid and hot-dry climates respectively. Exergy analysis is performed for the proposed solar-ice thermal storage system based on transient analysis. Results showed that, the proposed system is more effective approach in hot-humid than hot-dry climate and more efficient with all-water system than with all-air system. The maximum energy saving is 205.16 GJ having a percent of 27.5% in August for all water system in case of Alexandria city and 224.67 GJ with a percent of 25.38% in August for all-water system in case of Aswan city. All air system simulation showed maximum energy saving of 175.05 GJ with a percent of 18.13 % in case of August for Alexandria and 175.45 GJ having a percentage of 17.43% in case of Aswan in August. Moreover, the all-water system achieved a reduction in CO 2 emissions by 467 tons/year in Aswan city and 390 tons/year in case of Alexandria city. These reductions decrease to be 435 and 353 tons/year when the all-air system used for the same two cities. [ABSTRACT FROM AUTHOR]

The evaluations of Energy and Exergy are very useful for enhancing the performance and diminishing irreversibility of the solar thermal collectors respectively. The prime objective of the present investigation is to sort out a detailed article survey on the energy and exergy evaluation of different solar thermal collectors. The impacts of different heat transfer enhancers and geometrical parameters of solar thermal collector's receiver tube on energy and exergy efficiency have been introduced and examined. Moreover, a similar examination has been done to choose the best solar thermal collectors for the greatest energy and exergy effectiveness with negligible thermal losses. The literature from absorber coating shows that using black chrome and carbon coatings on the receiver plates of solar collectors has the potential to boost the collectors' thermal efficiency due to their high capacity. This study has also demonstrated that the utilization of hybrid nanofluids augmented the energy and exergy effectiveness fundamentally when contrasted to without hybrid nanofluids. The insertion of twisted tapes in the flow passage increases the rate of heat transfer by creating secondary flow which improves better mixing the fluid particles. The introduction of booster reflectors in the sides of the absorber plate reflects more sun rays on the collector surface. The use of phase change materials acts as an energy storage medium. It ensures the continuous run of the system. At last, this work will be valuable for the researchers taking research on energy and exergy investigations of solar thermal collectors. [ABSTRACT FROM AUTHOR]

The present study proposes a new optimal arrangement for a combined cooling, heating, and power (CCHP) system based on a proton-exchange membrane (PEM) fuel cell. The system is designed to supply the energy required by the households. The main purpose of this paper is to provide this configuration by considering several optimal parameters including exergy, energy, GHG reduction, and annual cost. The system is optimized by a newly developed metaheuristic, called fractional‑order search and rescue (FO-SAR) optimizer to minimize the annual cost and to maximize the economic efficiency of the CCHP system. The suggested system is then analyzed in different terms and a comparison of its results with two other methods including the original search and rescue (FO-SAR) optimizer and the NSGA-II is performed to show the effectiveness of the proposed system in different terms. [ABSTRACT FROM AUTHOR]

An energy system affordable plan selection using renewable energy is a significant problem for designing and manufacturing these systems. The fault detection and thermoeconomic diagnosis in the combined solar Rankine cycle and multi-stage flash (MSF) desalination system is analyzed. In the suggested energy system, the linear parabolic solar collector is utilized as a heat source for the organic Rankine cycle, the domestic hot water, and the multi-stageflash desalination system. First, the energy balances and exergy analysis are implemented in the considered system, the energy value and exergy parameter are calculated. The exergy cost parameters are calculated for all parts and streams with the thermoeconomic and exergy cost accounting investigation. Finally, the thermoeconomic diagnosis is performed, and the malfunction of each component is evaluated, and the effect of each component's irreversibility on the other part is investigated. Results show that the linear parabolic solar collector has the maximum malfunction. Still, the condenser in the organic Rankine cycle is the most effective component on irreversibility increment among its counterparts. [ABSTRACT FROM AUTHOR]

A novel biomass-driven heat and power cogeneration system comprising biomass gasification, a gas turbine, a Stirling engine, and a supercritical carbon dioxide cycle integrated with a domestic water heater was proposed in this work. Different biomass feedstocks (paper, wood, paddy husk, and municipal solid waste) were used in the gasifier as the input fuel. The devised system was analyzed from energy, exergy, exergoeconomic, and environmental viewpoints. Moreover, the effect of integrating the Stirling engine with the stand-alone CHP system is studied. Moreover, a detailed parametric analysis was performed to assess the effect of varying operating parameters on system efficiency. Finally, multi-objective optimization using genetic algorithm in MATLAB software was performed to obtain the optimum operating points. According to the results, using municipal solid waste as the input biomass resulted in the highest exergy efficiency by 41.36 % and the lowest C O 2 emission by 0.9021 t / M W h. Also, the system with the Stirling engine had a higher exergy efficiency and lower C O 2 emission than the system without the Stirling engine. According to the optimization results, the maximum obtainable exergy efficiency was 42.03 % , which was related to MSW. Also, the minimum achievable c p , t o t was 10.94 $ / G J , attributable to the respective paddy husk. [ABSTRACT FROM AUTHOR]

Advancement in technologies needs a critical heat removal technique for better exergo-economic performance of compact air heat exchangers. The passive technique is used for heat transfer improvement with various turbulators inserts TTI, PTTI, and DTTI in plain tube air heat exchanger. This paper investigates the exergo-economic sustainable performance of heat exchanger devices assisted with water-based different tripartite hybrid nanofluids under various geometrical turbulator inserts modifications. Simulation is proceeded for tripartite hybrid nanofluids of mainly six various compositions based on the nanoparticles morphology variant and three different turbulators inserts at the core of plain tubes heat exchanger. The four E's (Exergy, Energy, Economic, and Environmental) aspects with sustainability analysis of the device are studied with operating parameters. Results revealed that only nanofluid would not be useful for energy enhancement, while turbulator inserts with THNF result in a significant improvement in the thermohydraulic performance of the device. The device inserts with DTTI in plain tubes using THNF 6 results in the highest26% overall heat transfer coefficient, 2.94% exergy efficiency, 5.04% performance index, and higher sustainability index at low Reynolds number, meanwhile turbulator inserts yield to highest 91.94% operating cost and equivalent CO 2 emissions. DTTI with THNF 6 is preferred as working fluid as PEC ranges highest 1.42–2.35, and THNF 2 working fluid should be least preferred due to its high operating cost. [ABSTRACT FROM AUTHOR]

This paper deals with the exergy analysis of two experimental prototypes consisting of indirect evaporative cooling systems with different constructive characteristics. Both prototypes have been designed and manufactured in the Thermal Engineering Laboratory of the University of Valladolid. They are made of polycarbonate hollow panels of different cross section and connected into a heat recovery cycle. Each prototype has been tested at 4 levels of outdoor air volume flow (from 125 to 400 m3·h−1) and 4 levels of dry bulb temperature (from 25 to 40 °C). For each of the 16 different operating conditions the exergy destructed by each prototype has been calculated. Results show that the higher the dry bulb temperature at the primary air inlet, the higher the exergy destruction and the exergy losses. The exergy destruction increases when the wet bulb depression temperature of the secondary air inlet decreases, leading to more inefficient configurations. The value of the exergetic efficiency is in the order of 2–12 %. The optimum combination of operating conditions at any inlet temperature of the primary air can be proposed as: 300 m3h−1 and 200 m3h−1. for the wide and narrow plates prototype, respectively. [ABSTRACT FROM AUTHOR]

The integration of post-combustion capture (PCC) CO 2 technologies with power plants and high-emission industrial processes has become imperative for reducing carbon emissions and mitigating environmental impacts. This study focuses on addressing the significant energy consumption associated with PCC and explores the potential of using solar thermal energy to optimize configurations, thereby enhancing sustainability and reducing dependency on conventional power sources. Simulate various configurations under steady-state conditions using Aspen HYSYS V11 and Aspen Economic Evaluation software. The results indicate a substantial reduction in energy consumption to 2.1 GJ/ton CO 2 after the initial optimization steps. The key innovations involve the integration of Lean Vapor Compression (LVC), Solvent Split Flow (SSF), Rich Solvent Recycle (RSR), and Rich Vapor Compression (RVC). Further optimization was conducted by integrating a reboiler with parabolic trough collectors (PTC), to reduce energy penalties. The LVC + RVC + RSR + SSF + PTC configuration results reveal a notable improvement in exergoeconomic factors, ranging from 3.13% to 7.8%, highlighting the economic feasibility of the optimized configurations. Simultaneously, the energy penalty decreased by 11.1%, signifying enhanced sustainability in the proposed PCC system. This study contributes to the gap in research by demonstrating the efficacy of solar thermal energy in optimizing PCC configurations, providing a pathway towards more sustainable and energy-efficient solutions for carbon capture in high-emission industrial sectors. The findings offer insights for researchers, engineers, and policymakers aiming to address the pressing issue of carbon emissions from industrial processes. [Display omitted] • Integration of PCC with solar thermal energy enhances sustainability. • Aspen HYSYS v11 simulates basic configurations for PCC. • LVC, SSF, RSR, and RVC reduce energy consumption in PCC. • Reboiler with PTC integration decreases energy penalties. • LVC + RVC + RSR + SSF + PTC configuration improves exergoeconomic factors. [ABSTRACT FROM AUTHOR]

• A novel biomass-solar based multigeneration system is developed. • The energy, exergy, environment and economic assessments are conducted for the system study. • The thermal energy storage system is designed to store excess heat during the day. • The overall system's energy and exergy efficiencies are 37.68 % and 71.25 %, respectively. An integrated energy system is designed to produce various useful products, such as hydrogen, electricity, heat and cooling. This integrated plant utilizes various subsystems; solar power system, biomass energy system, steam Rankine cycle (SRC), Brayton cycle (BC), organic Rankine cycle (ORC), double-effect absorption system (DEAS), reverse osmosis system, and sonohydrogen production unit. The specific energetic, exergetic, economic and environmental impact assessment studies are carried out to evaluate the system's performance and sustainability. The engineering equation solver (EES) is used for these studies. The energy efficiencies for the BC, ORC and SRC are recorded as 29.69 %, 10.49 %, and 30 %, respectively. In regard to exergy efficiency, the BC, ORC and SRC achieve the following: 46.74 %, 62.73 %, and 53.43 %, respectively. Furthermore, the DEAS attains energetic and exergetic COPs of 1.67 and 0.65, respectively. Additionally, the overall system's energy and exergy efficiencies are found to be 37.68 % and 71.25 %, respectively. The results from the thermal energy storage system indicate that the heat production begins at 7:00 a.m., and the charging of the storage unit commences two hours after and continues until 5:00 p.m., in coinciding with the availability of sunlight. The economic analysis demonstrates that with an initial investment of $53.80 million, the integrated multigeneration system achieves a net present value ranging from $6.87 million to $173.4 million across different hydrogen selling prices, from $7000 to $13,000 per ton up to 2054. [ABSTRACT FROM AUTHOR]

The casing-wall static pressure of the centrifugal compressor behaves the double-peak distribution in the circumference at small flow rates (SM) but the single-peak distribution at large flow rates (LM). A previous study shows that the double-peak distribution is induced by the redistribution of impeller outlet flow rates. In this paper, by using the similar simplified method of directly imposing pressure boundary to the diffuser outlet, the original reason for the formation process difference of pressure distribution in the circumference at different operating conditions is further investigated. The results show that at LM, under the combined action of the specific downstream pressure distribution and the flow performance of the compressor itself, alternating low/high velocity airflow zones similar to those at SM cannot be established in the diffuser when the impeller outlet flow rates are redistributed. Therefore, the static pressure can only express the single-peak distribution in the circumference. In fact, whether the static pressure exhibits the double-peak or single-peak distribution in the circumference depends on whether the impeller outlet flow mutation can destroy the original flow balance. When the flow mutation is dominant, the double-peak distribution is created, whereas when the original flow balance is prevailing, the single-peak distribution is formed. [ABSTRACT FROM AUTHOR]

The present study contrasts the thermodynamics analysis of modified diesel engines with traditional diesel engines. Thermodynamics study is done by the use of energy and exergy analysis for diesel, B20 (blend of 80 per cent diesel by volume with 20 per cent mahua biodiesel) and LHR modification and LTC 15 per cent EGR fuelled with B20 blend and 5 per cent ethanol with various loads ranging from no load to full load. Implemented two technologies for increasing engine efficiency. One of the primary techniques is the Low Heat Rejection (LHR) concept (or the so-called "Adiabatic" engine) applied. In the engine cylinder, a ceramic layer of Alumina (Al2O3) was used to modify the Low Heat Rejection (LHR). Another technique is Low-temperature combustion (LTC) modes are added by joining the inlet and exhaust pipes through valves to control the exhaust gas at an optimal rate of 15 per cent. The findings of energy and exergy distribution in the engine were compared using optimum alterations with fuel blends such as 20 per cent mahua biodiesel and 5 per cent ethanol. From energy distribution, best shaft power (QBP) (2.8kW) is transformed from heat input observed in the optimum altered engine at full load conditions compared to others. Due to modifications employed in the engine and fuels. Maximum unaccounted energy (QUN) loss in diesel (44 %). And highest thermal efficiency (31.2 %) is revealed in B20E5 (LHR+15 % LTC). From exergy distribution, it noticed that the same trend of energy distribution and at 100 per cent load condition, maximum (12.54kW) in diesel and minimum (8.45 kW) in B20E5 (LHR+15 % LTC) has obtained input availability (Ain). The maximum conversion rate of availability in brake power (Abp) (0.61 kW) in B20 (LHR). Compared to diesel, second law or exergetic efficiency more in B20E5 (LHR+15 % LTC). Finally, concluded the B20E5 (LHR+15 % LTC) is found to be best compared to diesel and other combinations (B20, B20 (LHR)) due to the used optimum modifications in engine and fuel. [ABSTRACT FROM AUTHOR]

In this study, hydrofluoroolefin R515B was used rather than hydrofluorocarbon R134a to perform energetic, exergetic, environmental and enviroeconomic analyses on vapor-compression refrigeration systems with internal heat exchangers. The exergy efficiency, exergy destruction, and coefficient of performance for cooling mode (COP) were studied. EES (Engineering Equation Solver) program was employed for thermodynamic analysis. The impact on the COP, exergy destruction, and exergy efficiency of the system was investigated at various evaporator and condenser temperatures. Performance analysis shows that the COP of R515B refrigerant is like that of R134a. It has been found that the exergetic efficiency of R515B was slightly lower (about 1.40%) than that of R134a. It has also been found that at higher evaporation temperatures, the total exergy destruction increases. The most important exergy destruction occurs in the compressor. The environmental and enviroeconomic indexes of R515B refrigerant were like those of R134a. The results demonstrated that R515B may be a good alternative to R134a in the vapour-compression refrigeration systems with internal heat exchangers. [ABSTRACT FROM AUTHOR]

In this study, three desalination exergy analysis models including the Cerci et al. model (Model A), Drioli et al. model (Model B) and electrolyte solution model (Model C), were developed on an existing reverse osmosis (RO) desalination plant in Oman (Plant ALG). A modified ultrapure water (UPW) unit fed by Plant ALG has also been proposed (Plant A) based on the technology used in a UPW unit operated under the climate of Europe and fed by European river water (Plant B). The most suitable exergy model for characterizing the proposed UPW production plant was used. Model C was found to be the most proper model among its counterparts. It reflected the electrolytic behavior of the relevant streams and considered as the appropriate model. The major exergy destruction sites were also identified, and the exergy efficiency was calculated. The electro-de-ionization (EDI) and the RO unit were the highest exergy destructive components in Plant A. [ABSTRACT FROM AUTHOR]

The main objective of this article aims to enhance a single stage absorption refrigeration machine, using the ammoniawater pair as working fluid, and this from the improvement of its exergetic performances by means of a vapor rectification system. The rectifier makes it possible to emit a vapor enriched in pure fluid (ammonia) with a high flow rate; this one is thus transformed into condensate after condensation; as it also allows evacuating a liquid (water) in the form of reflux. Moreover, in order to show the role of the rectifier and to highlight its impact on the operation of the proposed installation, the methodology adopted in this work aims to develop a thermodynamic model of numerical simulation using the FORTRAN language according to two approaches. An energetic analysis approach which aims to assess, in a first time, the performance of the studied refrigeration installation. However, the exergetic approach tries to calculate the exergy efficiency, and thus to evaluate the losses of exergies of the refrigeration installation in a second time. Therefore, the obtained results showed a clear improvement in the exergetic efficiency, accompanied against by an optimization of the losses of exergies which are due to the irreversibility of the studied thermodynamic system. The novelty brought by the present study encourages the engineers and manufacturers to realize the future absorption refrigeration machines integrating rectifier systems. [ABSTRACT FROM AUTHOR]

Refrigeration and power are the most desirable requirements in commercial places and offices. Goswami cycle is one of the solutions to generate power and refrigeration simultaneously with less pollution. In the Goswami cycle, the power and refrigeration streams are connected in series, the refrigeration output is limited in a series arrangement. In the present study, parallel streams are proposed to improve the performance of the cycle. In the Goswami cycle, the saturated vapour is enriched for power and refrigeration. In the present study, the saturated vapour is used for the power generation, the saturated liquid is flashed to the intermediate pressure, and the generated wet vapours are enriched for refrigeration processes. It is observed that power generation is increasing with an increase in dryness fraction and the fall in basic solution concentration, whereas the refrigeration effect is growing with the fall in dryness fraction and increase in basic solution concentration. The modified cycle is consistently generating higher output than the conventional cycle. The thermal efficiency of the Kalina flash cycle is 29.05% higher and the exergy efficiency is 5.61% lesser than the Goswami cycle. [ABSTRACT FROM AUTHOR]

The journey to sustainability is becoming increasingly crucial in manufacturing, particularly in resource and energy intensive industries. In recent years, the matter of sustainability in industrial contexts has become an important point on the legislative agendas of many governments as well as in public opinion, with the latter becoming increasingly sensitive to enterprises' dedication to this problem. As a result, companies have started to implement sustainable approaches into their manufacturing processes and increased the amount of information about these practices to customers and stakeholders. The purpose of this work is to evaluate manufacturing sustainability using coupled exergetic and life cycle performance indicators, which are used to comprehend the outcomes of the studies as well as to qualitatively and quantitatively evaluate the models developed. The purpose of this study is to first present an overview of the metrics associated with the integrated or combined implementation of Exergetic Analysis and Life Cycle Assessment, their significance, and their application in specific use scenarios. Some illustrative indicators are then compared in an actual industrial case study, and the outcomes are discussed. Among the highlights, it is not yet able to determine a metric that measures the degree of manufacturing sustainability individually and thoroughly owing to the multifaceted character of the manufacturing processes. The overall conclusion is that combining Exergy with Life Cycle Thinking is indeed a beneficial solution for enhancing industrial processes, although the accuracy in measuring environmental, but primarily social and economic, concerns is not obvious. he assessment's interpretation is typically troublesome due to a lack of full and up-to-date data and confidence analysis, as well as a lack of scientific coherence. [ABSTRACT FROM AUTHOR]

Diethanolamine (DEA) solutions are used in refineries to sweeten gas. DEA is responsible for absorbing H 2 S from sour gas. In an Amine Regeneration Unit (ARU), the rich amine with H 2 S is regenerated. A refining column in the Middle East started commercial production in 2020. Using Aspen HYSYS V.11, an amine regeneration unit in the refinery that supplies lean amine to the delayed cooker unit for gas sweetening was simulated, and an exergy study was performed on various equipment. Exergy is destroyed in an irreversible process, while energy is converted from one type to another. The sum of the physical and chemical exergy is the total exergy. The chemical exergy was calculated using a series of equations embedded in Excel, while the physical exergy was calculated using HYSYS. The DEA concentration used is 25 wt%. Each equipment's exergy destruction rates, destruction efficiency, and percentage share of destruction were determined. The regenerator had the highest destruction rate of 2144.11 kW and an 80.21 percent share of total destruction. With a value of 326.00 kW and a percentage share of 12.20 percent of total destruction, the air cooler has the second-highest exergy rate. Exergy has a 99.70 percent overall efficiency. Due to system losses, the DEA concentration fell from 25% to 20% of the design value. The regenerator had the highest destruction rate of 2616.74 kW followed by the air cooler with a value of 294.61 kW. In DEA 20%, an exergy analysis was carried out. Exergy research showed the same percentage share distribution for equipment at a concentration of 20 DEA wt. percent. To find related equipment relationships, the results of the unit's exergy analysis were compared to those of another ARU exergy study at the same refinery plant. The regenerators were found to have the highest exergy destruction of the two units with a percentage share of the overall destruction reaching 80% followed by the air coolers with values reaching 9%. [ABSTRACT FROM AUTHOR]

• The atmosphere CLC is integrated with the combined sCO 2 -ORC for power generation. • The energy efficiency can reach 51.79% in the natural gas fired system. • The detailed technology and exergy analysis is conducted, and improvement strategies in off-design conditions are put forward. • The whole system performance is not sensitive to the CLC operating temperature, reducing the requirements for oxygen carriers and CLC reactors. Chemical looping combustion (CLC) has attracted wide interests with high-efficiency and near-zero energy penalty carbon capture. However, the low-pressure operation of the most adopted circulating fluidized-bed reactors restricts the application of the downstream combined (gas-steam turbines) cycle, leading to an unsatisfying system efficiency. For this reason, this paper integrates atmosphere CLC with the combined recompression supercritical CO 2 Brayton cycle and organic Rankine cycle (CLC-sCO 2 -ORC) for power generation. The proposed system was modeled and simulated with Aspen Plus to manifest its tech-economic feasibility. The sensitive analysis suggests that the optimal sCO 2 turbine inlet temperature and pressure are 700 °C and 280 bar, respectively, and the recompression split fraction is 0.72. Under the optimal condition, the energy efficiency of 51.79% is superior to the conventional natural gas combined cycle (NGCC) (49.38%) and other CLC-based power generation technology (50.13%). Exergy analysis was also performed to put forward some improvement strategies. Importantly, CLC operating temperature imposes nearly no impact on exergy loss. Besides, the economic indicator, levelized cost of electricity (LCOE) is supposed to be profitable at 79.17 $/MWh, which is lower than that of other CLC-based power generation system (83.12 $/MWh). [Display omitted] [ABSTRACT FROM AUTHOR]

Thermodynamic analyses of concentrating solar power plants and optimizing these cycles relying on the energetic and exergetic optimal efficiencies are quite common. However, it is found that just considering the efficiency of the system for performance optimization and neglecting the adverse effects of the plant's wrong operation timings, which is a function of the solar working fluid flow rate, can easily give misleading optimization results. This study's primary goal is to find the optimal operating point of the cycle in terms of the thermodynamic efficiencies considering the system's operating time. Thus, the Sliding Mode Control (SMC) approach is employed to provide a proper mass flow rate for the working fluid from the solar collector field to achieve a precise output temperature from the collectors in different operating conditions. Multi-objective optimization is performed using the Particle Swarm Optimization (PSO) algorithm. The results of power block sensitivity analysis indicate that a 70? increase in the solar collector outlet temperature remarkably enhances electricity generation and exergetic efficiency by 67 and 48%. The twoobjective optimization shows 22.01%, 2.10%, and 5.46% enhancement in response time, thermal efficiency, and exergetic efficiency, and the three-objective optimization reveals 3.68% and 3.74% improvement in efficiency (thermal and exergetic), respectively. [ABSTRACT FROM AUTHOR]

• Degradation of AR14 in water was accomplished using UV-LED/PS system. • Pulsed and continuous UV-LED illuminations were compared for AR14 degradation. • Impact of pulse irradiation parameters on photooxidative removal of AR14 was conducted. • Pulsed irradiation resulted in comparable degradation as continuous illumination. • Results demonstrated the higher quantum efficiency by lower pulse period and higher duty cycle. Removal of organic contaminants by UV-based advanced oxidation processes (AOPs) has been considered as one of the most effective procedures among environmental remediation methods. Ultraviolet light-emitting diodes (UV-LEDs) have possessed a unique place as an emerging technology in AOPs. In the present research, the impact of pulsed illumination on the overall efficiency of AR14 degradation by UV-LEDs and persulfate (PS) was considered. In comparison with continuous illumination, pulsed irradiation of UV-LEDs gifts the radiation of light in a programmed order to benefit its flexible pulse pattern, high-frequency utilization, and lower energy consumption attitudes. Duty cycles, pulse periods/frequencies, oxidant, and also removal kinetics were considered as operational parameters. Outcomes showed the efficacy of UV-LED and PS processes were both quite slow, while the hybrid route, UV-LED/PS showed great ability in degradation of AR14. Results depicted removal efficiency of (~93%) in UV-LED/PS system. Pulsed illumination has shown to be a beneficial technique providing higher output power and improved thermal management. 80% of the Duty cycle and 30 ms of the pulsed period was considered as optimized destruction state. Furthermore, results demonstrated that PS addition to the system significantly enhances the AR14 destruction efficiency by a pseudo-first-order rate constant (k) by 44 times. [Display omitted] [ABSTRACT FROM AUTHOR]

This study conducts dynamic modeling and analysis of an innovative semisolar greenhouse structure via MATLAB software in terms of energy, exergy, and economy. This modeling is used to predict the temperatures of four different area points inside a semi-solar greenhouse structure for the evapotranspiration of the crop. Measured data recorded from the constructed typical semi-solar greenhouse are used to evaluate the results of the proposed thermodynamic analysis. Measurements during the experiment show a considerable temperature difference of 20°C between the indoor and outdoor air. The mean values of 5.94% and 2.06°C for MAPE (Mean Absolute Percentage Error) and RMSE (Root Mean Squared Error) point to the accuracy of the thermal simulation. Furthermore, in different heat and mass transfer processes, the total exergy destruction values are analyzed. The target of this research is to provide suitable environmental conditions for the inside of the greenhouse. In this respect, the greenhouse air unit cost for each time step of one minute is inspected. By increasing the interest rate from 10% to 20%, the greenhouse air unit cost raises almost twice. Decrease of about 45.36% in total exergy destruction is obtained by the technique of applying double-layer glass as the greenhouse cover. [ABSTRACT FROM AUTHOR]

The present study brings together the benefits of the results of exergy, exergoeconomic, and exergoenvironmental analyses as well as optimization of a waste- to-energy power plant. First, exergoeconomic balance for each stream was calculated. To validate the current simulations, the actual data from the Amsterdam waste-to-energy power plant in working conditions were examined. Moreover, the behaviors of the influential parameters in the objective functions were evaluated. In order to perform multi-objective optimization, Multi-Objective Particle-Swarm Optimization (MOPSO) algorithm was employed. To obtain the optimum operating conditions, 14 design parameters and 3 objective functions were taken into consideration, with the total cost rate, total exergy efficiency of the cycle, and environmental impacts as the objective functions. Finally, the TOPSIS decision-making method determined the optimum-operating conditions. The results of exergy analysis indicated that the most exergy destruction belonged to the incinerator unit at 66%. Instead, the pumps contributed the least in this field (approximately 1%). Under the influence of the optimization process, the total exergy efficiency of the power plant increased from 30.89% to 38.9% at the total cost of 5188.05 USD/hour. A comparison of the obtained results from the optimization procedure revealed that introducing optimum working condition would cause an increase in the exergy efficiency and a decrease in the exergy destruction among the components. [ABSTRACT FROM AUTHOR]

In this paper, the thermodynamic performance of a boroxide-added glass evacuated tube heat pipe (ETHP) is studied, including energy, exergy, environmental, economic analysis, and sustainability index. It has been found that 50,87% of the energy loss of water and 50,86% of the exergy loss of water are caused by radiation. There are 4 collectors each collector 57 pipes as a total of 108 pieces pipes, a hot water tank, a heat exchanger, and a pump in the system. The water is used as a working fluid due to economic and common use in the system. In the result of this experimental study, we calculated energy and exergy efficiencies of the EHTP system as % 22,21 and % 13,68, respectively. In addition, the environmental, exergoenviromental, enviroeconomic, and exergoenviroeconomic values of the EHTP system are found 458,5 kgCO2/day, 456,5 kgCO2/day, 0,003708 $/day and 0.003692 $/day, respectively. Also, the sustainability index of the system is found as 1,159. [ABSTRACT FROM AUTHOR]

In the present study, numerical method is used to investigate the exergy and energy characteristics of the air flow through tube banks which their arrangements are common inline or staggered. Furthermore, new arrangement called "twisted tube bank" is introduced and perused. Realizable K-ε model is selected for the investigation of the turbulence impact. The influence of dimensionless transverse and longitudinal pitches, Reynolds number, twist angle and dimensionless duct diameter on three objective parameters, COP, CEP and second law efficiency are analyzed. Equations are suggested for prediction of these three objectives parameters. Furthermore, a multi-objective method will be introduced and used to obtain the optimum cases of the geometrical and operational variables. Results indicate, if the Reynolds number is doubled, the CEP increases by 39.5% while, the second law efficiency and the COP reduce by 75.7% and 10.2%, respectively. Furthermore, it was realized, the application of the twisted tube bank is superior when the CEP and the second law efficiency are the objective parameters simultaneously while, for other multi-objects the inline arrangement is more appropriate. The optimum cases will be achieved at twist angle equal to 43° and 84°. [ABSTRACT FROM AUTHOR]

• An innovative integration of compressed air energy storage and desalination units. • Comprehensive thermodynamic, exergoeconomic, and economic assessments of the system. • A comparative study of the performance of the proposed system with isobaric and isochoric tanks. • Achieving an energy and exergy round-trip efficiency of 62.18% and 57.84%. • Achieving a payback period of 3.82 years with a total profit of $27.65 million for the case study. Electricity and potable water are two vital resources for the world's population. A pioneering green energy storage system for power and potable water production has been introduced and investigated in this context. The innovative system integrates compressed air, pumped hydro, and thermal energy storage, along with multi-effect desalination. This combination enables the generation of power and potable water without exerting any adverse impact on the environment. This technology manages the start-up time of the desalination unit by using a low thermal energy storage unit and allows potable water to be generated throughout the day. By conducting a comprehensive analysis including energy, exergy, economic, and exergoeconomic, the performance of the system has been carefully examined and the effect of various parameters has also been considered. Finally, the advantages of the proposed system are compared to the conventional system. According to the study, round trip efficiency and total cost rate have been calculated as 62.18% and 618.6 USD/hr, respectively. Based on a case study conducted in the coastal areas of the state of California, the proposed system has the potential to generate 138 m3 of potable water and 88.11 MWh of electricity per day. This could lead to a total profit of 27.65 million dollars with a payback period of 3.82 years. [ABSTRACT FROM AUTHOR]

This paper aims to provide comprehensive 4E (energy, exergy, exergoeconomic, and exergoenvironmental) and advanced exergy analyses of the Refrigeration Cycle (RC) and Heat Recovery Refrigeration Cycle (HRRC) and comparison of the performance with R744 (CO2) and R744A (N2O) working fluids. Moreover, multi-objective optimization of the systems has been considered to define the optimal conditions and the best cycle from various perspectives. In HRRC, heat recovery is used as a heat source for an organic Rankine cycle. The energy and exergy analysis results show that utilizing HRRC with both refrigerants increases the coefficient of performance (COP) and exergy efficiency. COP and exergy efficiency for HRRC-R744 have been obtained 2.82 and 30.7%, respectively. Due to the better thermodynamic performance of HRRC, other analyses have been performed on this cycle. Exergoeconomic analysis results show that using R744A leads to an increase in the total product cost. Total product cost with R744 and R744A have been calculated by 1.56 $/h and 1.96$/h, respectively. Additionally, to obtain the processes' environmental impact, Life Cycle Assessment (LCA) is used. Exergoenvironmental analysis showed that using R744A increases the product environmental impact by 32%. Owning to the high amount of endogenous exergy destruction rate in the compressor and ejector compared to other equipment, they have more priority for improvement. Multi-objective optimization has been performed with exergy efficiency and total product cost objective functions as well as COP and product environmental impact for both refrigerants, which indicates that HRRC-R744 has better performance economically and environmentally. In optimal condition, the value of exergy efficiency, total product cost, COP, and the product environmental impact have been accounted for by 28.51%, 1.44 $/h, 2.76, and 149.01 mpts/h, respectively. [ABSTRACT FROM AUTHOR]

The present paper aims to study the effect of cooling air inlet methods on gas turbine compressors on increasing their efficiency. After modeling gas turbine cycles with absorption and compression systems in the EES software, these cycles' performance is investigated for all equipment of the cycle from thermodynamic, exergy, and exergoeconomic aspects. In the absorption system, the conventional solution of lithium bromide-water is used as a two-component fluid, and in the compression cycle, the R134a operating fluid is used. According to the results, with the rise in the system's inlet air temperature, the total output work of the gas turbine decreases. Based on the exergoeconomic analysis, the exergy destruction cost dominates the initial cost, resulting in the exergoeconomic factor's decline. Relationship predicted by Group Method of Data Handling (GMDH) to reduce the computation time of optimization. The studied systems are then subjected to two-objective optimization by the Particle Swarm algorithm using MATLAB software. The objective functions are related to the exergy efficiency and total cost rate. The results reveal contradictory behavior in these two objective functions so that with the increase in the exergy efficiency, the total cost rate increases. [ABSTRACT FROM AUTHOR]

The exergy analysis is performed for the flow of fluid and transfer of thermal energy inside the sector-by-sector (SBS) and tube-in-tube (TIT) types of the helically coiled heat exchangers (HCTHs). The turbulent transfer of thermal energy for each side of the heat exchangers is simulated using the Realizable K-epsilon model. The model is verified by comparing the current work values of the Nusselt numbers with the values obtained using the previous empirical correlations. New equations are suggested for the estimation of the exergy efficiency and the coefficient of the exergy performance as functions of the both sides Reynolds numbers, dimensionless coil diameter and pitch. These heat exchangers performance are compared using these equations. It was concluded that, if the dimensionless coil diameter is doubled, the exergy efficiency decreases by 21.8%, 25.7% and 21.1% and the coefficient of the exergy performance decreases by 8%, 9.3% and 14.8% for the heat exchangers with semi-circle cross section, quadrant-circle cross section and the TIT heat exchangers, respectively. Furthermore, the application of the SBS heat exchangers with semi-circle and quadrant-circle cross sections are highly recommended instead of the common TIT types. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present a novel concept for control of hybrid photovoltaic-thermal systems: a Maximum Exergy Point Tracker. It operates by evaluation of the exergetic and energetic performance of a solar photovoltaic-thermal (PV/T) system, to find the maximum cell temperature that produces at least the same exergy as the system without cogeneration. This maximum working temperature is a very important issue for proper design of cogeneration plants and their operation. The operation with concentration showed better results for energetic and exergetic efficiencies, in addition to an increase in the maximum operating temperature of the photovoltaic cell, compared to operation without concentration. The results allow selecting a suitable photovoltaic cell for a given application, depending on its reference efficiency and temperature coefficient. • It is an approach to find the maximum cell temperature in an hybrid/cogeneration system that keeps the exergy of the system, quantifying the quality of the produced energies. • This is a very important issue for proper design of cogeneration plants. • Based on this approach, a maximum exergy point tracking can be developed. [ABSTRACT FROM AUTHOR]

The application of the integrated solar-energy-based systems for water desalination and power production to some Iranian coastal regions has been investigated. For this purpose, the Integrated Multi Effect Desalination (MED) and Solar Rankine Cycle (SRC) are used. This work investigates the effects of the main thermodynamic parameters on the systems located at the southern Iranian cities of Chabahar, Qeshm, Kish and Asaluyeh. For each selected sites, the net power output of the system is 50 MWe. The results show that total exergy destruction is the highest for steam generator and cavity receiver which is in the range of 61% to 64% in several cases. Also, the Chabahar has the less total exergy destruction and the freshwater production is about 270.8 kg/s as most production. In addition, at other sites, the integrated cycle can produce about 266.2 kg/s of freshwater. Furthermore, the most total exergy destruction is related to Asaluyeh. [ABSTRACT FROM AUTHOR]

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