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Hydrogen fuel has gained global attention as a potential alternative to conventional fuels as it reduces greenhouse gas emissions and addresses energy sustainability challenges. In addition, biofuel (Azolla pinnata) is highly productive having limited negative impacts with an exemplary productivity rate. The energy-exergy analysis in CI engine's is an effective method for determining its efficiency and effectiveness. This paper highlights the effects of diesel, H 2 enriched diesel, and H 2 enriched B40 (60% diesel + 40% Algal Biodiesel) on the energetic and exergetic efficiency of a dual-fuel diesel engine with a rated speed and power of 1500 rpm and 3.5 kW respectively. The analysis was done at varying engine loads: low loads (25%), medium loads (50%), and high loads (75%), respectively. The energy and exergy for 40% hydrogen-enriched B40 increased by 8.77% and 23.85%, respectively, compared to neat diesel operation at higher loads. In addition, the irreversibility of 40% hydrogen-enriched B40 decreased by 13.82% at higher load conditions as compared to base diesel operation. The sustainability index of 40% hydrogen-enriched B40 was 1.38 compared to 1.28 of diesel, showing an improvement of 7.82%. The theoretical energy-exergy analyses showed an error less than 5% compared to BTE validating the results of the energy-exergy analyses performed theoretically. • Diesel and biodiesel (Azolla pinnata) blends enriched with H 2 are used as fuel. • This paper compares energy-exergy of 40% H 2 enriched-diesel and B40 with diesel. • Energy-Exergy efficiency with 40% H 2 enriched B40 increases at all loads. • Total irreversibility in the system decreases with hydrogen and biodiesel addition. • Sustainability index of 40% H 2 enriched B40 was better than conventional fuels. [ABSTRACT FROM AUTHOR]

A theoretical analysis is conducted using a nano-coated plate evaporator surface for fish preservation. Copper and alumina nanoparticles mixed with the base material (Steel) are considered for the evaporator material. Different brines (ethylene glycol, propylene glycol, potassium acetate, and calcium chloride) act as secondary refrigerants. Various performance parameters (pumping power, exergy rate change, irreversibility, exergic efficiency, non-dimensional exergy, and irreversibility distribution ratio) based assessment has been performed. The maximum percentage reduction in non-dimensional exergy and irreversibility, and maximum percentage rise in exergy rate change, irreversibility distribution ratio, and exergic efficiency have been acquired for propylene glycol brine. The pumping power decreased by 2.5% for alumina-copper hybrid nanoparticle-based material. The irreversibility and non-dimensional exergy have been reduced by 1.5%, whereas the exergy change rate, exergic efficiency, and irreversibility distribution ratio enhanced by 0.5%, 0.5%, and 2.5%, respectively, for PG brine (percentage-wise). The study reveals that the surface coated with nanoparticles provides better exergic performance. [ABSTRACT FROM AUTHOR]

Rising concerns over fossil fuel depletion and plastic pollution have driven research into biodegradable alternatives, such as polylactic acid (PLA). Microbial fermentation is preferred for lactic acid production due to its ability to yield enantiomerically pure lactic acid, which is essential for PLA synthesis, unlike the racemic mixture from chemical synthesis. However, commercial lactic acid production using first-generation feedstocks faces challenges related to cost and sustainability. Macroalgae offer a promising alternative with their rapid growth rates and carbon capture capabilities. This review explores recent technological advancements in macroalgae physicochemical characterization, optimization of fermentation conditions, and innovative pretreatment methods to enhance sugar conversion rates for L-LA production. It also covers downstream processes for L-LA recovery, presenting a complete macroalgal biorefinery system. Environmental impacts and economic prospects are assessed through exergy and techno-economic analyses. By valorizing macroalgae detritus, this study underscores its potential to support a sustainable biorefinery industry, addressing economic feasibility and environmental impact. [ABSTRACT FROM AUTHOR]

In the application scope of large-scale supermarkets, the practicality of transcritical CO 2 refrigeration device has been confirmed to be quite satisfying. A modified two-stage transcritical CO 2 refrigeration cycle with an ejector and a subcooler (MTC) is proposed in this paper. In the modified cycle, the ejector recovers expansion works and reduces irreversible losses in the throttling process. The subcooler provides subcooling degree for the CO 2 entering the low-temperature (LT) evaporator, thus increasing the refrigeration capacity and improving the COP of the modified cycle. Thermodynamic analysis has shown that the exergy efficiency (η e x) and COP of MTC under given operating condition has been enhanced by 13.7 % and 14.2 % compared to BTC. The discharge temperature at the outlet of high-pressure compressor in MTC is decreased by 8.3℃. Under typical operating condition, the optimal discharge pressure of MTC is 9.07 MPa, which is lower than that of BTC. The correlation to calculate optimal discharge pressure for single-stage CO 2 refrigeration cycle is also suitable for MTC under given operating conditions. The MTC has also shown better performance under variable operating conditions. For MTC, when the temperature at the outlet of gas cooler increases from 35 – 45℃, the COP and η e x are enhanced by 14.1 % - 16.1 % and 12.8 % - 14.2 % compared to BTC, respectively. When gas cooler outlet pressure decreases from 11.0 to 7.5 MPa, the COP and η e x are enhanced by 14.0 % - 22.8 % and 13.4 % - 18.7 %. As the evaporating temperature at the cold side of subcooler increases from -25 to -15℃, the COP and η e x increase from 1.82 to 1.98 and 27.4 % to 29.7 %. With the ratio of refrigeration capacity (R e c) between medium-temperature evaporator and low-temperature evaporator varies from 0.7 to 1.2, the COP and η e x are improved by 10.7 % - 16.3 % and 10.7 % - 15.4 % compared to BTC. There is the maximum exergy loss at gas cooler in the MTC, whereas that of BTC is located in the expansion valve before LT evaporator. The economic analysis shows the cost per unit of exergy of MTC is decreased by 11.5 % under typical operation condition. According to simulation results, the modified cycle has better performance in severe working conditions such as high gas cooler outlet temperature and low gas cooler outlet pressure in the given range of working conditions compared to BTC. [ABSTRACT FROM AUTHOR]

This paper presents a conventional air source heat pump cycle (CHPC) and two dual-temperature air source heat pump cycles (DTHPC1 and DTHPC2). DTHPC1 employs two condensers, while DTHPC2 adds an extra compressor and combines the ejectors on top of DTHPC1. Compared with the conventional heat pump cycle, the new dual-temperature heat pump DTHPC2 can provide hot water at one additional temperature and still have high performance. In this paper, the refrigerants R1234yf and R1234ze(E) were selected as suitable for the cycle conditions. The cycle performance under different conditions was simulated and compared based on energy analysis methods and exergy analysis methods. The main performance parameters included COP h , η ex , etc. The results demonstrate that the COP h and η ex of DTHPC2 and DTHPC1 are greater than those of CHPC under identical conditions. Specifically, at an ambient temperature of approximately -10 °C, high-temperature hot water of approximately 65 °C, and low-temperature hot water of approximately 35 °C, the COP h of DTHPC2 and DTHPC1 increased by 45% and 32.7%, respectively, in comparison to CHPC. Similarly, the η ex of DTHPC2 and DTHPC1 increased by 27.1% and 28.9%, respectively. [ABSTRACT FROM AUTHOR]

• Thermodynamic analysis of a novel two-stage ejector refrigeration cycle is made. • Cycle performance and exergy efficiency are improved by the separation of mixtures. • COP improvement increased by 41.6 % and 89.6 % for 134a/R32 and R600a/R290. • Three largest exergy destruction occurs in the ejector, condenser, and generator. To improve the ejector refrigeration cycle performance, this paper presents a theoretical thermodynamic analysis of a novel two-stage ejector refrigeration cycle (TSERC) with a gas-liquid separator using R134a/R32 and R600a/R290 as refrigerant. By separating the relatively low-boiling-point and high-boiling-point refrigerants, the cycle compression ratio decreases, the cycle performance increases, and the energy utilization efficiency can be improved. Energy and exergy analysis were conducted for the traditional single-stage ejector refrigeration cycle (SSERC) and TSERC. The effect of the mixture mass fraction on cycle performance under a fixed external heat source operating condition was studied, and the cycle performance comparisons between TSERC and SSERC at different evaporation temperature, condensation temperature and generation temperature were conducted. Results show that for TSERC, the maximum COP values 0.126 and 0.11, the maximum exergy efficiency 4.51 % and 4 % are obtained as the low-boiling-point mass fraction equals 0.6 and 0.4 respectively for R134a/R32 and R600a/R290. It is found that exergy destruction mainly occurs in the low-pressure sub-cycle of TSERC, the top three largest exergy destruction components are ejector 1, condenser 1 and generator 1, while the smallest exergy destruction occurs in pump 2. In addition, cycle performance comparison between SSERC and TSERC shows that the maximum COP improvement increased by 41.6 % and 89.6 % for 134a/R32 and R600a/R290 for TSERC, while the maximum entrainment ratio improvement increased by 32.4 % and 87.6 %. Moreover, it is concluded that the cycle performance improvement of TSERC is more significant at lower evaporation temperature, higher condensation temperature, and lower generation temperature compared to SSERC. [ABSTRACT FROM AUTHOR]

The tomato pomace (TP), which is a by-product of the production of tomato paste, was dried in a novel custom-designed daylight simulated photovoltaic assisted dryer (DPVD). The different light applications (daylight, UV light, daylight + UV light, and without light), different air velocities (1.5 and 2 m/s), and different heating source modes (hot air and infrared) were applied to dry TP having a moisture content of 80.60 ± 0.73% to the moisture content of 7.66 ± 1.72%. The average water activity values of all dried samples were measured as 0.52 ± 0.08. Analysis was conducted to compare sun drying with the effects of process conditions on the quality (color properties, lycopene, β-carotene, and total mesophilic aerobic bacteria count) and performance (energy efficiency, exergy efficiency, specific moisture evaporation rate, and improvement potential) characteristics of TP. The effects of process conditions for each heating source mode were determined separately, and the improvement of the system performance for each mode was investigated. The effect of the process conditions on total aerobic mesophilic bacteria (TAMB) count was similar in general. In the infrared heating mode, the loss in lycopene and β-carotene contents was 59.55 ± 2.22 and 57.87 ± 2.51 minimum for 1.5 m/s air velocity without light application and for 2 m/s with ultraviolet + daylight application. In general, the performance of the system decreased in case of using ultraviolet light. The retention in the lycopene and β-carotene contents was higher in the infrared mode with light applications compared to hot air mode without light. The optimum drying conditions were air velocity of 2 m/s with "daylight" assistance in the hot air heating mode and with "ultraviolet + daylight" assistance in the infrared heating mode. All the energy and the daylight source used in drying applications were obtained from the sun, a renewable energy source, thanks to the photovoltaic panel and the solar tube units in the novel custom-designed drying system. [ABSTRACT FROM AUTHOR]

In recent years, the research in the field of medicinal plants as therapeutic supplements has increased significantly. Lavender extract is widely used among medicinal plant products due to its unique therapeutic properties. Since drying processes require high energy, this study was conducted to study the performance of the spray dryer in the production of lavender extract powder at three levels of air temperature 150°C, 180°C, and 210°C, three levels of compressed air flow rate 6, 8, and 10 L/min and ratios of maltodextrin‐drying aid to the mass of dry matter of the extract 0%, 25%, and 50% by response surface method. For this purpose, the energy efficiency and exergy of the powder production process were examined. According to the obtained results, increasing the inlet air temperature and the inlet air flow rate increased the energy efficiency and exergy and decreased the energy efficiency and exergy, respectively. The energy efficiency of the drying process varied in the range of 6.55%–15.87%, and the exergy efficiency (ηex) of the drying process in the range of 2.87%–5.84%. Also, the ηex of the spray dryer was calculated in the range of 20.05%–38.78%. Based on the energy efficiency and exergy, the optimal production of lavender plant extract powder was obtained at the air temperature of 210°C, the compressed air flow rate of 6 L/min, and the amount of drying aid of 11.9 g/L. [ABSTRACT FROM AUTHOR]

Water shows a strong tendency to absorb the energy of wavelengths of 3 and 6 µm, which are in the infrared (IR) range. Therefore, IR dryers are used to dry food and fruits that have a high‐water content. Thus, modeling and optimizing energy and exergy parameters of terebinth drying in an IR–rotary drum (RD) dryer were evaluated using the response surface methodology. Independent factors included IR power and rotary rotation speed, and response factors were specific energy consumption (SEC), energy efficiency (EFF), exergy efficiency (EXEFF), specific exergy loss (EXLOSS), and exergy improvement potential (EIP). According to the obtained results, the range of EFF and EXEFF was between 28.93%–9.11% and 0.88%–6.62%, respectively. As IR power and RD speed increased, SEC (123.75–39.21 MJ/kg), EXLOSS (3.97–2.97 MJ/kg), and EIP (3.62–1.009 MJ/kg) decreased, while EFF and EXEFF increased. The results obtained in this study showed that the optimal IR drying power is 616.39 W, and the optimal rotary rotation speed is 13.46 rpm. [ABSTRACT FROM AUTHOR]

This rebuttal letter reports some physical facts, which are contradictory with known physical facts, in the article entitled "Exergy analysis and nanoparticle assessment of cooking oil biodiesel and standard diesel fueled internal combustion engine" by I. Yildiz, H. Caliskan, K. Mori, Energy and Environment 31(8) (2020) 1303–1317. [ABSTRACT FROM AUTHOR]

Evaporative cooling is an environmentally friendly and low-cost method to deliver cooling load in hot climates. It has been proposed as an alternative to traditional vapour compression systems, mainly due to its lower power consumption and the ability to provide cooling without the need for refrigerants. The present study investigates a novel regenerative indirect evaporative cooling system to address the high cooling demands in hot climates. The proposed unit consists of commercially available aluminium plate cross-flow heat exchangers. Within the study, system performance is simulated in MATLAB software and numerical results are validated with experimental testing results. In the analysis, the effects of exhaust-to-inlet air ratio, inlet air temperature and inlet air relative humidity on the system energetic and exergetic performance were investigated. Individual effects of the inlet parameters on the thermal, mechanical and chemical exergies of the inlet, product and exhaust air streams were also investigated. Maximum wet bulb effectiveness values were achieved as 0.99 and 1.06 for the single and double effect configurations, respectively. In all inlet air conditions, an optimal exhaust-to-inlet air ratio of 0.4 was found to maximize the cooling capacity. Maximum exergy destruction rate was 35W. On the other hand, yearly potential energy savings of 695 kWh was calculated by replacing a vapour compression system with the proposed regenerative evaporative cooler. [ABSTRACT FROM AUTHOR]

Performance enhancement of a system is always preferred. The thermal efficiency of currently available simple solar water heater (SSWH) are generally in between 50 and 60%. The present work describes the use of different inserts like twisted tapes and springs on the performance enhancement of flat plate collector (FPC) of modified solar water heater (MSWH) under natural and forced convective situations for the performance enhancement. The experimental studies has been carried out at Nagpur ((21.1241° N, 79.0023° E) to investigate the performance of FPC of a MSWH with different inserts. Two different experimental setups were analyzed and compared for the investigation of performance. The first experimental setup investigated without any modification and under natural convection while other setups are investigated with modifications and under natural and forced convective situations. The experiments have been performed with plain twisted tape (PTT) inserts having five twisted ratios (y/W) viz. 2.0, 2.5, 3, 3.5 and 4, twisted tape with helical coil spring inserts (TTS) having three twisted ratios (y/W) viz. 2.0, 3 and 4, and traverse twisted tape (TTT) having three twisted ratios (y/W) viz. 2.0, 3 and 4. The PTT, TTS & TTT inserts are used with a fixed thickness of 1 mm, width 12 mm and length 1900 mm. The experiments has conducted for the different Reynolds number of, 4000 ≤ Re ≤ 24,000 using water as a working fluid. In all the cases Nusselt number increases with Reynolds number but the friction factor decreases. Some conclusions and recommendations based upon the above experimentation are presented at the end. [ABSTRACT FROM AUTHOR]

The use of hydrofluorocarbons as refrigerants is reduced because of the increasing greenhouse effect. Air refrigeration system is environmentally friendly with air as working medium. In this study, a reverse-bootstrap air refrigeration cycle was proposed for fresh air-conditioning, which eliminated the hot heat exchanger to reduce volume and weight, and a full fresh air refrigerator was developed and tested in a psychrometric test room. Combining the characteristic curves of a motor-driven turboexpander–compressor (MTEC), a numerical model was established to analyze system off-design performance. The relative deviations between the predictions and experimental data were within 10%. The test and calculation were conducted at standard conditions (the outdoor and indoor dry and wet bulb temperature is 35/24°C and 27/19°C, respectively). The MTEC operating at design rotating speed 38 krpm could supply fresh air with a flow rate of 517.4 kg/h and temperature of 12.0°C, and a cooling capacity of 2.93 kW was obtained with a system Coefficient of performance (COP) of 0.315. The optimal COP and corresponding rotating speed will change with the variation of environmental parameters. As the outdoor temperature increases from 32 to 38°C, the optimal COP decreases by 29.6% and the corresponding rotating speed increases from 39.6 to 47.6 krpm. Moreover, when the outdoor relative humidity increases from 35% to 55% and the indoor temperature increases from 23 to 31°C, the COP decreases by 36.8% and increases by 31.9%, respectively. The advanced exergy analysis indicate the system avoidable exergy destructions account for 54.9%. Under the avoidable conditions, the efficiency of compressor, expander, and motor is 0.85, 0.85, and 0.95, respectively, the system COP can reach 0.946. The exergy destruction analysis of components indicates the importance to optimize the compressor. [ABSTRACT FROM AUTHOR]

The growing global demand for clean, reliable, and affordable energy presents a critical challenge, especially with the need to reduce reliance on fossil fuels and minimize environmental impact. This article proposes a hybrid biomass and geothermal system to address these needs, providing a sustainable solution for hydrogen and electricity production while reducing peak demand. The system incorporates an ammonia synthesis cycle that captures nitrogen from the atmosphere, producing ammonia as a carbon-free energy source and a flexible energy storage alternative to costly, environmentally hazardous batteries. By applying a machine learning-optimized grey wolf algorithm, the system achieves 546.1 kg/day of ammonia production, 3224 kW of net power output, 43.7% energy efficiency, and a low Levelized Cost of Energy (LCOE) of 65.7 USD/MWh, with emissions of 130.9 g/kWh. Optimization further improves efficiency to 44.1%, reduces emissions to 127.1 g/kWh, and lowers costs to 63.4 USD/MWh. Exergy analysis identifies major areas of energy loss, offering pathways for future improvement. [Display omitted] • A novel hybrid system based on biomass and geothermal hybridization is introduced. • The system is integrated with the ammonia cycle driven by green hydrogen. • Machine learning-aided optimal energy management is proposed via Grey Wolf method. • The system generates 546 kg of ammonia daily as a promising energy career/storage. • Optimization achieves 2.3 USD/MWh and 3.8 g/kWh lower cost and emission. [ABSTRACT FROM AUTHOR]

This study presents and analyses three plant configurations of the Ocean Thermal Energy Conversion (OTEC) technology. All the solutions are based on using the OTEC system to obtain hydrogen through an electrolyzer. The hydrogen is then compressed and stored. In the first and second layouts, a Rankine cycle with ammonia and a mixture of water and ethanol is utilised respectively; in the third layout, a Kalina cycle is considered. In each configuration, the OTEC cycle is coupled with a polymer electrolyte membrane (PEM) electrolyzer and the compression and storage system. The water entering the electrolyzer is pre-heated to 80 °C by a solar collector. Energy, exergy, and exergo-economic studies were conducted to evaluate the cost of producing, compressing, and storing hydrogen. A parametric analysis examining the main design constraints was performed based on the temperature range of the condenser, the mass flow ratio of hot and cold resource flows, and the mass fraction. The maximum value of the overall exergy efficiency calculated is equal to 93.5% for the Kalina cycle, and 0.524 €/kWh is the minimum cost of hydrogen production achieved. The results were compared with typical data from other hydrogen production systems. [Display omitted] • An OTEC based offshore hydrogen production system is analysed by exergo-economics. • Three different OTEC cycles are compared: two Rankine and Kalina. • System includes OTEC, electrolyzer, H 2 compression, water desalination and heating. • Kalina cycle is the best performing, with 93.5 %, 83–87% for Rankine. • The cost of H 2 from Kalina OTEC is estimated at 17.3 €/kg (0.52 €/kWh). [ABSTRACT FROM AUTHOR]

This paper proposes a novel scheme of biomass-regenerated two-stage desiccant-supported greenhouse cooling in tropical and subtropical regions. The system's goal is to provide the ideal thermal environment inside a greenhouse for the growth of different kinds of Orchids. Two-stage desiccant-based cooling is used in the proposed system to obtain a low humidity ratio inside the greenhouse. The desiccant is regenerated using a biomass-based heating system. The first law analysis and the exergy analysis of the system's individual components have been included in the study. The results of the thermal model (greenhouse temperature) have been compared with those of a reference model study available in the literature. The mean absolute error for the humidity ratio and greenhouse air temperature is 4.3% and 4.5%, respectively. The model's predictions are in good agreement with the results of the reference model. The performance study reveals that the maximum greenhouse air temperature can be restricted within 26 °C even during the peak sunshine hours for a typical day in May which represents the peak summer season in India. The proposed system COPth varies from a minimum of 0.54 to a maximum of 1.02 for a typical hot and humid day of July. The proposed system can exhibit a maximum exergy efficiency of 33% at 6 AM for a representative day in July. The maximum exergy destruction occurs at the DW1 (39.25%) and regeneration heater (21.69%). The payback period of the proposed system is 8.2 years, considering a 15-year life span. [ABSTRACT FROM AUTHOR]

This research paper analyzes the use of plasma technology to process biomass in the form of dried, mixed animal manure (dung containing 30% moisture). The irrational use of manure as well as huge quantities of it can negatively impact the environment. In comparison to biomass fermentation, the plasma processing of manure can greatly enhance the production of fuel gas, primarily synthesis gas (CO + H2). The organic part of dung, including the moisture, is represented by carbon, hydrogen, and oxygen with a total concentration of 95.21%, while the mineral part is only 4.79%. A numerical analysis of dung plasma gasification and pyrolysis was conducted using the thermodynamic code TERRA. For 300–3000 K and 0.1 MPa pressure, the dung gasification and pyrolysis were calculated with 100% dung + 25% air and 100% dung + 25% nitrogen, respectively. Calculations were performed to determine the specific energy consumption of the process, the composition of the products of gasification, and the extent of the carbon gasification. At 1500 K, the dung gasification and pyrolysis consumed 1.28 and 1.33 kWh/kg of specific energy, respectively. A direct-current plasma torch with a power rating of 70 kW and a plasma reactor with a dung processing capacity of 50 kg/h were used for the dung processing experiments. The plasma reactor consumed 1.5 and 1.4 kWh/kg when pyrolyzing and gasifying the dung. A maximum temperature of 1887 K was reached in the reactor. The plasma pyrolysis of dung and the plasma–air gasification of dung produced gases with specific heats of combustion of 10,500 and 10,340 kJ/kg, respectively. Calculations and experiments on dung plasma processing showed satisfactory agreement. In this research, exergy analysis was used to quantify the efficiency of the plasma gasification of biomass. One of the research tasks was to develop a methodology and establish standards for the further standardization of monitoring the toxic emissions of dioxins, furans, and Benzo[a]pyrene. [ABSTRACT FROM AUTHOR]

In the present investigation, the exergy of an innovative technique involving the integration of curved helical tubes with twisted passages was experimentally presented. This technique aims to improve the thermofluid characteristics by involving the swirl intensity of fluid flow in a twisted tube helical coil (TTHC). Six identical geometries with different pitch ratios of 36 mm, 54 mm, and ∞ (smooth/no twisted) were experimentally explored at two different inner tube profiles of triangular and square cross-sections in counter flow arrangements. The experimental runs were carried out at 10,300 ≤ Rei ≤ 37,800 and 2400 ≤ Reo ≤17,600 for both the inner and annulus fluids, respectively. The results showed that the Nusselt number, Nu, increased by 39.6% and 41.5% for triangular and square inner twisted cross-section profiles, respectively, at a of 36 mm at the expense of increasing f by 37.6% and 60.7%, respectively. The results also showed that the thermal performance factor reached 1.3 and 1.25 for a of 36 mm for the triangular and square inner twisted tube profiles, respectively. A comprehensive study is performed to analyze the TTHC from thermal, frictional, and exergetic viewpoints. New correlations for expecting the annulus Nuo and fo are presented. [ABSTRACT FROM AUTHOR]

Energy efficiency strategies in industrial breweries examine the inefficiency of thermal systems from a thermodynamic perspective. However, understanding the costs of inefficiencies in systems, including non-thermodynamic costs, requires exergoeconomics. This study examined wort production in a standard Tier-1 brewery from the tripod of energy, exergy, and exergoeconomics analyses to assess the performance of brewing sections and to pinpoint components that contributed the most to exergy destruction and product cost rate. The energy analyses for the production system showed that the total specific energy for processing 10.05 tons of brew grains to 346.98 hL high-gravity wort was (86 ± 1) MJ/hL at an operational energy efficiency of 30.35%. The exergetic analyses showed that the cumulative exergetic destruction was 3.2737 MW, with the brewhouse section contributing 89.25% of the system's inefficiencies. Also, the analyses showed that the wort kettle (42.7911%), mash tun (10.8086%), preheater (10.0683%), whirlpool (8.3522%), and adjunct kettle (6.2705%) are the top five components with the highest rates of cumulative exergy destruction. The exergoeconomic analyses revealed that the cost rate of processing chilled wort was estimated to be 0.0681 USD/s per overall exergetic efficiency of 6.61%. The five most significant components are the wort kettle (53.70%), whirlpool (16.42%), mash filter (10.44%), mash tun (6.875%), and adjunct kettle (3.31%) based on the relative total cost increases for the production processes. Additionally, wet steam throttling resulted in a 2.51% increase in exergetic efficiency, a 1.60% drop in exergetic destruction rate, and a decrease in cost rates to 0.0675 USD/s. [ABSTRACT FROM AUTHOR]

This paper investigates energy and exergy analyses of 660 MW capacity supercritical coal power plant with single reheat and regenerative. The fuel utilized in the plant is a combination of sub‐bituminous and lignite coal. It is found that the turbine section of the system exhibits the highest energy efficiency (around 94.17%) and exergy efficiency (around 90.73%). Also, 82.07% of the total exergy destruction is found for the boiler, and the remaining 17.93% of the irreversibility is determined for the turbine, condenser, and other components. The overall cycle energy efficiency at maximum load is computed as 40.77%, while the overall cycle exergy efficiency at maximum load is found to be 39.69%. These findings provide valuable insights into the performance of the power plant and suggest the improvements needed in performance enhancement of the boiler. [ABSTRACT FROM AUTHOR]

To meet the strict requirement on whole chain of vaccine production, storage, transportation, and distribution, most researches have been done on cascade refrigeration systems to achieve high operation performance, while a research gap on the performance exploration of eco‐friendly refrigeration systems still exists. In this paper, a comprehensive thermodynamic model was established to analyze the operation performance of a pre‐cooled cascade refrigeration system with eco‐friendly refrigerants propane (R290) and ethane (R170). Based on the present thermodynamic model, the performance optimization on the R290‐R170 cascade refrigerator was made with considerations of degree of subcooling, degree of superheat, evaporation temperature, condensation temperature, cascade condensation temperature, and cascade temperature difference. Variations of the coefficient of performance, exergy destruction, and total exergy efficiency of the refrigeration cycle were analyzed. Two mathematical correlations yielding the optimal cascade condensation temperature and maximized coefficient of performance were developed by multilinear regression analysis. When the evaporation temperature is − 60°C, the maximized coefficient of performance and total exergy efficiency are 1.276 and 49.51%. This paper demonstrates the potential for improving the R290‐R170 cascade refrigeration system and furnishes the basis for further exploration on ultra‐low‐temperature refrigerators. [ABSTRACT FROM AUTHOR]

The energy consumption of hydrogen liquefaction is often quantified as being approximately 40 % of hydrogen's lower heating value (LHV), making hydrogen liquefaction energy-intensive. Boundary conditions for energy consumption values in the literature are, however, often unclear, rendering these values questionable. Two methods can nevertheless significantly decrease energy consumption: (1) implementing improved liquefiers; and (2) utilising liquid hydrogen exergy – the reversible liquefaction work – stored in the liquid. Liquid hydrogen exergy equals 11.5 % LHV. And in comparison: per energy content, liquid hydrogen exergy is 5.5 times liquefied natural gas exergy. To estimate the energy savings potential of combining liquefier improvements and exergy utilisation, the exergy efficiency of improved liquefiers is calculated (44 %) and used as a quality measure. The same efficiency is assumed for exergy utilisation processes. The net energy consumption for the liquefaction - regasification chain is thereby reduced to 13-26 % LHV, depending on boundary conditions. • The H 2 liquefaction-regasification chain is evaluated by exergy analyses. • LH 2 exergy is 11.5 % of H 2 's lower heating value (LHV H 2 ), LNG exergy is 2.1 % of LHV CH 4 . • Improved H 2 liquefiers achieve 44 % exergy efficiency. • LH 2 exergy recovery during regasification estimated with liquefier exergy efficiency. • Energy consumption of H 2 liquefaction-regasification chain reducible to 13-26 % LHV H 2 . [ABSTRACT FROM AUTHOR]

This novel investigation emphasizes the implications of bio-based areca nut husk (ANH)-derived nano-additive on energy, exergy, exergoeconomic, and sustainability aspects of compression ignition engine. X-ray-photoelectron-spectroscopy analysis exhibits the inherent content of oxygen, and nitrogen in ANH at different binding energy levels directing towards its possible use as nanoadditive in diesel at ppm level. From the Brunauer–Emmett–Teller results, it is revealed that ANH nanoparticle is porous in nature having an average pore size of 4.89 nm and a surface area of 3.047 m2g−1. For engine experiments, ANH nano-additives are incorporated at three different proportions at ppm level, and the experiments are carried out at varying loads. The rheological results of nanoadditive mixed diesel exhibit that pumping can be done at a very broad range for diesel with 15 ppm ANH (Diesel-15 ppm) which will endure continuous flow to the engine. The highest energy, exergy efficiency, and sustainability index are observed for Diesel-15 ppm. [ABSTRACT FROM AUTHOR]

• Energy, exergy, environment analyses and multi-objective optimization are performed for vortex tube coupled with transcritical refrigeration cycle (TVTC). • The parametric investigation is done to assess the thermodynamic performance of TVTC. • The cooling capacity of TVTC is found to be 10.1 % to 21.1 % higher than that of TVCR. • The maximum COP and exergetic efficiency of TVTC are higher than those of TVCR. • The evaporator temperature is the most influential input parameter in multi-objective optimization. The present study deals with the thermodynamic investigation of vortex tube coupled with trans-critical vapour compression refrigeration cycle (TVTC), followed by environmental analysis and multi-objective optimization. In this research, effect of various operating and design parameters is studied on the performance of TVTC. Furthermore, a comparison is made between the outcomes of TVTC and simple trans-critical vapour compression refrigeration cycle (TVCR). Results show that the optimum gascooler pressure for TVTC is observed to be lower than that of TVCR. Also, the cooling capacity and COP of TVTC are observed to be 10.1 % to 21.1 % and 2.3 % to 11.3 %, respectively, greater than those of TVCR. Moreover, the exergetic efficiency of TVTC is 2.3 % to 11.3 % higher than that of TVCR for the investigated range of evaporator and gascooler exit temperatures. The environmental penalty cost (per unit cooling capacity) of TVTC is 3.5 % to 12.2 % lower than that of TVCR. Furthermore, the coefficient of structural bond is calculated in order to choose the most sensitive parameters for system's performance. Additionally, genetic algorithm-based multi-objective optimization has been performed, with the evaporator temperature serving as the primary determining factor in establishing the optimal solution. This finding can guide the development of TVTC-based systems for a wide range of applications. [ABSTRACT FROM AUTHOR]

The combination of renewable energy and liquefied natural gas (LNG) cold energy can effectively improve energy utilization efficiency and achieve the goal of energy conservation and emission reduction, which is one of the important directions of future development. This work proposed a cascade organic Rankine cycle (ORC) driven by a geothermal heat source and an LNG heat sink. Seven organic fluids are chosen as candidates to form different working fluid pairs. The effects of the main design parameters on system performance are carried out through the thermodynamic analysis. Then, the optimal design conditions and fluid selection schemes are searched based on the single-objective optimization results. Finally, the exergy destruction study is conducted under the optimal design conditions and working fluid pair. Results showed that the cascade ORC system using the working fluid pair of R601/R290 had the highest exergy efficiency, which could reach 20.02%. At the same time, under the optimal design conditions, the secondary cycle condenser and LNG direct expansion brought high exergy destruction, which was respectively 29.3% and 25.8%, and followed by the two turbines in the cascade ORC system, which were 16.1%, 11.2% and 7.7%. [ABSTRACT FROM AUTHOR]

The present work focuses on the impact of combustion phase shifting from CDC (conventional diesel combustion) to RCCI (reactivity controlled compression ignition) mode of operation under various premixed ratios of hydrogen on the combustion, performance and exhaust emissions of a partially modified CI (compression ignition) engine. The hydrogen premix ratios are varied from 10% to 60% with 10% increment and the engine is tested at 0.9 kW, 1.8 kW, and 2.7 kW. The experimental results have shown that the hydrogen participation up to 40% premixed ratio improves the homogeneousness and stability of the combustion, resulting in 8.19% increase in cylinder pressure and 27.81% increase in heat release rate (HRR) at 2.7 kW brake power. It is also observed that the premix phase of combustion is faster with up to 40% hydrogen participation as the 50% mass burn is found to shift towards TDC. At the same operating point, the combustion is also found to be more stable with 72% reduction in COVIMEP. The brake thermal efficiency (BTE) increases by 10.07% when operating at 2.7 kW brake power with a 40% premix ratio, compared to diesel CDC operation. The unburned hydrocarbon (UHC), carbon monoxide (CO), and PM emissions are reduced by 9.17%, 21.68%, and 9.51%, respectively, for the hydrogen premixed ratio of 40%, with a marginal increase in the oxide of nitrogen (NOX) emissions. [ABSTRACT FROM AUTHOR]

The development of sustainable bioenergy technologies is positioned as a fundamental pillar for the development of local economies and a promising solution for the energy sector decarbonization. In the aim to contribute to these efforts, the present research considers a comprehensive process evaluation for a sustainable fuel production. Furthermore, chicken fat waste is considered as feedstock for the production of biodiesel with two glycerol valorization roots: The first configuration suggests a glycerol—biodiesel blend combustion for energy supply to the transesterification process, while the second process propose hydrogen production through in-site glycerol reforming. These two configurations were simulated using Aspen Plus software. Then, in order to select the optimal process configuration, multiple decision criteria including fundamental process engineering assessment tools such as energetic, exergetic, environmental and economic assessments were performed. Results revealed that hydrogen case presents a better thermal efficiency with 79.34% compared to 70.33% in the heat integrated configuration. The exergetic efficiency of the two configurations are 76% and 65% in hydrogen case and heat integrated case respectively. Environmental results indicate that 1 GJ of energy produced from chicken fat generates approximately 13.63 kg CO2-eq via hydrogen case and 26.75 kg CO2-eq by Heat integrated cases. From an economic point of view the hydrogen case is found more profitable. [ABSTRACT FROM AUTHOR]

This study concerns the development and experimental investigation of Direct Urea-Hydrogen Peroxide Fuel Cells (DUHPFC), with a particular emphasis on electrode preparation using nickel zinc iron oxide coated on stainless steel foil via the electrochemical deposition method, and the performance evaluation of single cells under varying operational conditions is also performed. This electrochemical deposition helps achieve a uniform and stable anode coating, which exhibits the high catalytic activity and stability, resulted in significantly enhanced urea oxidation reaction. The research further identifies an optimal performance for a single cell at 25 °C with 9 M KOH and 0.5 M urea, achieving a peak power density of 46.38 mW/cm2. The single cell demonstrates an open circuit voltage (OCV) of 0.72 V. Both energy and exergy efficiencies are further investigated for the cell performance and found to be 58% and 24%, respectively, at 5 M KOH. The electrochemical impedance spectroscopy (EIS) results reveal a significant reduction in impedance, from 30-Ωcm2 at 25 °C to 15-Ωcm2 at 65 °C, indicating an enhanced ionic conductivity and a reduced resistance. The present study results suggest that optimizing the electrode composition and operational parameters significantly improves the DUHPFC's performance, offering valuable insights for future fuel cell development. [Display omitted] • Urea and H₂O₂ enhance electrochemical reactions in DUHPFC systems. • Nickel zinc iron oxide catalyst boosts urea oxidation and cell efficiency. • Optimizing electrode composition and conditions improves DUHPFC performance. • Temperature and KOH concentration affect urea oxidation and cell efficiency. • Testing confirms the stability and durability of the developed anode. [ABSTRACT FROM AUTHOR]

Hydrogen is a promising zero-carbon fuel, and its application in the micro-combustor can promote carbon reduction. The structural design of micro-combustors is crucial for combustion characteristics and thermal performance improvement. This study investigates the premixed combustion characteristics of hydrogen/air in a micro-cylindrical combustor with double ribs, using an orthogonal design method to assess the impact of various geometric parameters on thermal performance. The results indicate that the impact of rib height, rib position, and inclined angle is greater than rib width and their interactions, while their influence decreases in that order. Increased rib height improves mean wall temperature and exergy efficiency due to an expanded recirculation region and increased flame–wall contact, but negatively affects temperature uniformity and combustion efficiency. Although double ribs enhance performance, placing them too close may reduce heat transfer due to the low-temperature region between the ribs. When the double ribs are positioned at the axial third equinoxes of the micro-combustor, the highest mean wall temperature is achieved. Meanwhile, with a rib height of 0.3 and an inclined angle of 45°, the micro-combustor achieves optimal thermal performance, with the mean wall temperature increasing by 61.32 K. [ABSTRACT FROM AUTHOR]

This paper presents an analysis and optimization of a polygeneration power-production system that integrates a concentrating solar tower, a supercritical CO2 Brayton cycle, a double-flash geothermal Rankine cycle, and an internal combustion engine. The concentrating solar tower is analyzed under the weather conditions of the Mexicali Valley, Mexico, optimizing the incident radiation on the receiver and its size, the tower height, and the number of heliostats and their distribution. The integrated polygeneration system is studied by first and second law analyses, and its optimization is also developed. Results show that the optimal parameters for the solar field are a solar flux of 549.2 kW/m2, a height tower of 73.71 m, an external receiver of 1.86 m height with a 6.91 m diameter, and a total of 1116 heliostats of 6 m × 6 m. For the integrated polygeneration system, the optimal values of the variables considered are 1437 kPa and 351.2 kPa for the separation pressures of both flash chambers, 753 °C for the gasification temperature, 741.1 °C for the inlet temperature to the turbine, 2.5 and 1.503 for the turbine pressure ratios, 0.5964 for the air–biomass equivalence ratio, and 0.5881 for the CO2 mass flow splitting fraction. Finally, for the optimal system, the thermal efficiency is 38.8%, and the exergetic efficiency is 30.9%. [ABSTRACT FROM AUTHOR]

Improving the efficiency of solid oxide fuel cells (SOFCs) is critical for advancing clean energy solutions on a global scale. One major challenge in enhancing SOFC efficiency is reducing anode diffusion polarization, which can significantly hinder performance. This study addresses this issue by investigating the effects of anode tortuosity and porosity on the exergy efficiency of SOFCs. The novelty of this research lies in its comprehensive numerical model, which uniquely incorporates detailed material properties and their impact on SOFC performance—specifically focusing on anode tortuosity and porosity. Using advanced Multiphysics software, we developed a model that solves mass, electron transfer, and energy equations discretized via the finite differences method. The study meticulously examines how variations in these parameters influence SOFC efficiency, providing new insights into optimal anode design. Our methodology involves simulating different anode configurations to pinpoint the key parameters that affect exergy efficiency, thereby minimizing the experimental costs and time associated with traditional approaches. The quantitative results of this study are significant. We found that an anode tortuosity of 5.5 and a porosity range of 0.05–0.1 optimize exergy efficiency, achieving a 15% improvement compared to conventional designs. Additionally, a mean pore radius between 15 and 20 µm was identified as optimal for enhancing cell voltage. These findings elucidate the critical relationship between anode material properties and SOFC performance, offering a practical pathway to improving efficiency. This research provides a novel numerical approach to understanding and optimizing anode characteristics in SOFCs. By highlighting the importance of specific material properties, such as tortuosity and porosity, and demonstrating their impact on exergy efficiency, this study offers valuable guidance for future SOFC design and development. [ABSTRACT FROM AUTHOR]

In this study, the performance of a micro-combustor with an exhaust gas recirculation (EGR) channel was analyzed based on the second law of thermodynamics. Effects of the inlet velocity (V in), equivalence ratio (ϕ), separating wall length (L 1) and nozzle diameter (d in) on entropy generation and exergy efficiency of the micro-combustor were investigated. In general, chemical reaction contributes most to the total exergy destruction (>60%), followed by heat conduction, mass diffusion, and viscous dissipation. Meanwhile, all parts of the entropy generation rate increase with the increase of V in and ϕ. However, the entropy generation rates caused by chemical reaction and heat conduction decrease with the increase of L 1. The entropy generation rates due to chemical reaction and heat conduction show opposite variation trends respect to d in. An increase of V in and ϕ results in higher exergy destruction and exergy loss of the micro-combustor, the largest exergy destruction and exergy loss are 3.06 W and 5.94 W under V in = 200 m/s and ϕ = 1.0, respectively. While a longer separating plate length leads to a decrease in the exergy destruction and exergy loss. Exergy destruction and exergy loss change a little with d in and their values are around 1.6 W and 3.4 W, respectively. Exergy efficiency of the micro-combustor increases with the increase of V in and L 1 , but exhibits a non-monotonic variation with ϕ. A maximum exergy efficiency of 51.3% is achieved at V in = 200 m/s under ϕ = 1.0, d in = 0.20 mm and L 1 = 4 mm. In addition, the exergy efficiency decreases from 38.5% to 37.5% as d in increases from 0.20 mm to 0.30 mm under the same mass flow rate. [Display omitted] • The primary contributor to combustion irreversibility is chemical reaction. • Entropy generation by reaction rises with V in and ϕ , but reduces with L 1 and d in. • Entropy generation by heat conduction rises with V in and d in , but reduces with L 1. • Exergy loss from outer walls surpasses exergy destruction in the micro-combustor. • Exergy efficiency varies non-monotonically with equivalence ratio. [ABSTRACT FROM AUTHOR]

Combining finite time thermodynamics and exergetic analysis, analogous to the definition of ecological efficient power for heat engines, this paper proposes a unified performance indicator for various cycles, exergy-based efficient ecological function (E ɛ ) which is defined as product of exergy-based ecological function and coefficient of performance, and introduces it into performance optimization of endoreversible simple air refrigerator cycle coupled to constant-temperature heat reservoirs. Relations among E ɛ , pressure ratio (π) and heat conductance distribution ratio (u) are derived by using numerical method. The cycle performance indicators which include cooling load (R), coefficient of performance (ɛ), and exergetic loss rate (E out/T 0) under the different maximum objective criteria are compared. Taking π as optimal variable, and taking R, ɛ, cooling load density (r), E ɛ and their combinations as optimization objectives, multi-objective optimizations, totally 15 optimization combinations, are performed by using NASG-II algorithm. The results demonstrate that, the maximum E ɛ criteria can better reflect the compromise among R, ɛ and E out/T 0. The Pareto solution sets are majorly distributed in 2.5–20 when quadru-objective optimizations are performed. The option selected by LINMAP decision-making method is closer to ideal solution when bi-objective optimization of ɛ and r is carried out. [ABSTRACT FROM AUTHOR]

Dual-shell reactors using hydrothermal flames as internal heat source were proposed for supercritical water gasification (SCWG) and oxidation (SCWO) of oily sludge to achieve fast preheating and avoid corrosion, salt plugging, and overheating. The SCWG and SCWO systems with hydrogen-rich syngas and electricity outputs, respectively, were established and simulated using Aspen Plus 11. Simulation models were validated by comparing with experimental products and temperature profiles. The maximum exergy destruction coefficients of 28.01% and 24.31% appear in the combustion reactor for both the SCWG and SCWO systems, respectively, indicating the indirect preheating method with hydrothermal flame is critical to the energy efficiency. The increase of reaction temperature promotes hydrogen but inhibits methane formation in the SCWG, and more steam but less syngas is output at higher reaction temperatures. Although more steam and electricity outputs are present at higher reaction temperatures for the SCWO, more fuel input is required. Lower exergy efficiencies are obtained at higher reaction temperatures in both the SCWG and SCWO systems for more energy is output as low grade steam. Less fuel input is required for both the SCWG and SCWO systems at higher feed concentrations, and higher exergy efficiencies can be obtained. The net treatment cost for the SCWG and SCWO systems are 119.19 and 215.47 USD/t, respectively, indicating the SCWG is more economically competitive compared with the SCWO. • Reactors with hydrothermal flames were proposed for SCWG and SCWO of oily sludge. • SCWG and SCWO systems with energy output were built and simulated by Aspen Plus. • The maximum exergy destruction appears in the combustion reactor for SCWG and SCWO. • Lower exergy efficiencies appear at higher temperatuers for more steam output. • The SCWG has certain economic superiority compared with the SCWO. [ABSTRACT FROM AUTHOR]

Among the available energy storage technologies, pumped thermal energy storage (PTES) is emerging as a potential solution for large-scale electrical energy storage with high round-trip efficiencies and no geographical limitations. However, PTES requires a low-cost, high-temperature heat source to achieve reasonable round-trip efficiencies. Moreover, organic Rankine cycle-based PTES systems require high-performance and environmentally friendly working fluids. In this study, the thermodynamic performance of a geothermal integrated PTES system using environmentally friendly working fluids is investigated. The mathematical model of the geothermal integrated PTES system is developed using the first and second laws of thermodynamics and implemented in Engineering Equation Solver (EES). With the developed model, the thermodynamic performance of the PTES system for different working fluids, including butene, cyclopentane, isobutene, R1233zd(E), R1234ze(Z), R1224yd(Z), HFO1336mzz(Z), n-hexane, and n-pentane was investigated. For geothermal fluid outlet temperatures between 60 °C and 120 °C and geothermal fluid inlet and outlet temperature differences across the evaporator between 20 °C and 60 °C, the net power ratio, i.e., the ratio of the electrical energy discharged to the electrical energy used to run the charging cycle, is between 0.25 and 1.40. This shows that the system has the potential to give back more than 100% of the electrical energy used during charging under certain conditions. High net power ratios are obtained for a combination of high source temperatures and low geothermal fluid inlet and outlet temperature differences. [ABSTRACT FROM AUTHOR]

This study presents an exergetic examination of a vapour compression refrigeration system. The exergetic balance conditions have been defined. Experimental work depending on the change of the capillary tube length (800, 1000, and 1200) mm with refrigerant mass flow rate changes from (10.3 to 21.3) kg/hr has been done to represent the different exergy flow occurring in the system components. The results were compared for each condenser temperature, evaporator temperature, coefficient of performance, exergy losses, exergy efficiency, efficiency defects, and rational efficiency. Results have been presented graphically. The finding indicated that the coefficient of performance decreased by 7% as the capillary length increased from 800 to 1200 mm. Also, the total exergy increases by 2.3% with increasing mass flow rates. [ABSTRACT FROM AUTHOR]

Energy consumption is rising in unison with population increase, industrialization, and urbanization. A solar heating system is one of the devices that supply consumers with thermal energy. Consequently, it is imperative to conduct an exergy analysis on this system in order to identify genuine, beneficial energy loss, which is not detectable by the first law of thermodynamics. The exergy analysis in this study is conducted using experimental data from the solar heating system in a space that includes a solar collector, pump, connections, and radiator, all of which operate with water as the working fluid. The exergy analysis is conducted for indoor heating spaces, radiators, and solar collectors under a variety of operating conditions, including a range of ambient temperatures and heating demands. The findings indicated that the rate of energy degradation is directly influenced by the heating burden and ambient temperature. The energy degradation rate in the solar collector increased by 14.25% when the ambient temperature varied from 15 to 21℃, while it decreased in the radiator and interior space by 55.59% and 57.57%, respectively. Conversely, as the heating capacity increased from 1100 to 1250 W, the energy degradation rate in the radiator and the indoor space increased by 15.45% and 19.81%, respectively. [ABSTRACT FROM AUTHOR]

Heat energy conservation is essential in all aspects. Various sectors, such as HVAC (Heating, Ventilation, and Climate control), Chemical treatment, Thermoelectric plants, and Chilling units face challenges in utilizing effects, reusing heat, and preserving resources. Caloric can be recovered using a heat exchanger. Thermal exchangers necessitate substantial Monetary investment in favor of various Funds and operational costs. Therefore, it is essential to develop HE. That are more energy-intensive, costly, and resource-efficient. The approach to enhance heat transfer is nanofluid inserts with tape insertion. Through this research, we consolidated the parameters influencing the nanofluid's operation to improve the heat tray. A study has been carried out on advancing heat transmission using twisted taut. [ABSTRACT FROM AUTHOR]

Hydrogen liquefaction is essential for the efficient storage and transportation of hydrogen. In the liquefaction process, catalytic ortho‐para conversion is crucial to achieve a product with at least 95 % para‐hydrogen to reduce boil‐off losses. The proposed hydrogen liquefaction process using a catalyst‐filled heat exchanger for continuous ortho‐para conversion is modeled through steady‐state thermal simulations in Aspen HYSYS. Additionally, an ejector is integrated to reliquefy boil‐off gas. The proposed design achieves a specific energy consumption (SEC) of 10.50 kWh (kgLH2${\mathrm{kg}}_{{\mathrm{LH}}_2}$)−1 and an exergy efficiency (EXE) of 30.1 %, which is 18 % lower in SEC compared to processes with separate converters. The integrated approach enhances energy utilization and offers references for future hydrogen liquefiers. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The accurate optimisation of absorption chillers is often impeded by idealised models that overlook system interactions and machine complexities. This study introduces a validated mathematical description for predicting the primary indicators of non-idealised absorption chillers, accounting for factors such as the electrical work of the Solution Circulation Pump, entropy changes within the refrigerant cycle, and exergy losses. Validation against 13 years of data (2008–2021) from the University of Debrecen's absorption chiller indicated close agreement, with deviations within acceptable limits. The use of a solution heat exchanger shifted cooling indicators towards their minima. Sensitivity analyses indicated that a 2.5% reduction in condenser temperature increased COP by 41.3% and Cooling Exergetic Efficiency by 15.5%, while a 2.5% reduction in the Heat Fraction Factor improved both by 34%. Adjusting absorber temperature and Heat Fraction Factor down by 2.5%, alongside a 2.5% rise in generator temperature, resulted in a 100.8% increase in COP and a 52.8% boost in Cooling Exergetic Efficiency. These insights provide a solid foundation for future optimisation strategies in real-life absorption chiller systems. [ABSTRACT FROM AUTHOR]

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Relying solely on electrical energy storage for energy regulation makes it difficult to provide a stable and efficient energy supply for microgrid systems currently. Additionally, the economic cost of microgrids and the rate of energy use present a challenge that must be addressed. A strategy for allocating capacity for multi-energy microgrids that takes energy efficiency and hydrogen energy into account is offered as a solution to the aforementioned issues. Initially, the construction of the multi-energy microgrid system takes into account the thermoelectric coupling properties of hydrogen energy devices. Second, the system's energy utilization level is measured using the exergy efficiency analysis. Next, the multi-objective capacity optimization allocation model of the multi-energy microgrid system is established, with the exergy efficiency and system economic cost serving as the objective functions. Lastly, the multi-objective model is solved using the ε -constraint approach to find the Pareto frontier, and Technique for Order Preference by Similarity to an Ideal Solution is employed for decision-making. The example results demonstrate that, when compared to a traditional microgrid using electric energy storage, the proposed model can effectively lower the system's economic cost and improve exergy efficiency. Additionally, multi-objective capacity optimization can be used to strike a balance between exergy efficiency and the system's economic cost. For relevant studies on the capacity allocation of multi-energy microgrids, this work can be a helpful resource. [ABSTRACT FROM AUTHOR]

Refrigeration plays a significant role across various aspects of human life and consumes substantial amounts of electrical energy. The rapid advancement of green cooling technology presents numerous solar-powered refrigeration systems as viable alternatives to traditional refrigeration equipment. Exergy analysis is a key in identifying actual thermodynamic losses and improving the environmental and economic efficiency of refrigeration systems. In this study exergy analyze has been conducted for a solar-powered vapor compression refrigeration (SP-VCR) system in the region of Ghardaïa (Southern Algeria) utilizing R1234ze(E) fluid as an eco-friendly substitute for R134a refrigerant. A MATLAB-based numerical model was developed to evaluate losses in different system components and the exergy efficiency of the SP-VCR system. Furthermore, a parametric study was carried-out to analyze the impact of various operating conditions on the system's exergy destruction and efficiency. The obtained results revealed that, for both refrigerants, the compressor exhibited the highest exergy destruction, followed by the condenser, expansion valve, and evaporator. However, the system using R1234ze(E) demonstrated lower irreversibility compared to that using R134a refrigerant. The improvements made with R1234ze are 71.95% for the compressor, 39.13% for the condenser, 15.38% for the expansion valve, 5% for the evaporator, and 54.76% for the overall system, which confirm the potential of R1234ze(E) as a promising alternative to R134a for cooling applications. [ABSTRACT FROM AUTHOR]

Considering environmental challenges and the diminishing share of energy expenses in the final product cost, evaluating energy‐intensive systems is crucial. This study examines the drying process of wet glass containers in a honey processing plant using a continuous convection dryer through energy and exergy analyses. Mass, energy, and exergy balances were performed using EES software. The energetic performance indicators revealed a heat loss rate of 3.33 kW, energy efficiency of 20.45%, and specific energy consumption of 11711.25 kJ kg‐1H₂O. Exergetic performance indicators included an exergy destruction rate of 24.05 kW, improvement potential rate of 20.79 kW, total exergy efficiency of 14.14%, exergy efficiency of 11.14%, specific exergy consumption of 2763.92 kJ kg‐1H₂O, and a sustainability index of 1.16. Results indicated that 60.12% of exergy destruction is related to air heating, with exhaust air losing 200.54 kW, equivalent to 89.84% of total input energy, suggesting exhaust air recirculation to reduce losses. Practical applications: The wet container dryer in a honey processing plant, as the most energy‐intensive component, was chosen for thermodynamic analysis. Mass, energy, and exergy balances were conducted to evaluate the system's thermodynamic performance. The exhaust air dryer lost 200.54 kW, equivalent to 89.84% of the total input energy, without utilization. Additionally, the results showed that 60.12% of the total exergy destruction in the convective drying process was related to air heating. Therefore, recirculating the exhaust air from the dryer moves the system toward an ideal thermodynamic state. [ABSTRACT FROM AUTHOR]

This study provides a comprehensive analysis of the thermal and exergy characteristics of a dairy plant that produces yoghurt. This study aims to perform a comprehensive analysis of the thermal and exergy aspects of a dairy facility that produces yoghurt. This study also seeks to improve the accuracy of the results by evaluating the reliability of the energy and production data. A comprehensive analysis of energy and exergy is utilized to enhance the yoghurt production process. Moreover, the Grassmann-Sankey diagram is employed to produce a map of energy density. The process's energy and exergy efficiencies were assessed by taking into account the enhancements and alterations made in addition to the existing implementations. Analysis of the yoghurt production process revealed that the total energy input was 113.9 [kW], the total energy output was 72.05 kW as well and the energy efficiency was 63.3%. The exergy input and output for the yoghurt production process were calculated to be 48.95 [kW] and 29.77 [kW], and the exergy efficiency was determined to be 60.8%. This study is expected to promote the growth of livestock and agriculture in the energy sector, and is forecasted to act as a catalyst for future research. This study, which is the first of its kind in the region and is expected to stimulate further research, reveals that improving energy efficiency and conservation in the production of yoghurt products enhances the factory's overall energy efficiency. [ABSTRACT FROM AUTHOR]

Advanced airborne power generation technology represents one of the most effective solutions for meeting the electricity requirements of hypersonic vehicles during long-endurance flights. This paper proposes a power generation system that integrates a high-temperature fuel cell to tackle the challenges associated with power generation in the hypersonic field, utilizing techniques such as inlet pressurization, autothermal reforming, and anode recirculation. Firstly, the power generation system is modeled modularly. Secondly, the influence of key parameters on the system's performance is analyzed. Thirdly, the performance of the power generation system under the design conditions is simulated and evaluated. Finally, the weight distribution and exergy loss of the system's components under the design conditions are calculated. The results indicate that the system's electrical efficiency increases with fuel utilization, decreases with rising current density and steam-to-carbon ratio (SCR), and initially increases before declining with increasing fuel cell operating temperature. Under the design conditions, the system's power output is 48.08 kW, with an electrical efficiency of 51.77%. The total weight of the power generation system is 77.09 kg, with the fuel cell comprising 69.60% of this weight, resulting in a power density of 0.62 kW/kg. The exergy efficiency of the system is 55.86%, with the solid oxide fuel cell (SOFC) exhibiting the highest exergy loss, while the mixer demonstrates the greatest exergy efficiency. This study supports the application of high-temperature fuel cells in the hypersonic field. [ABSTRACT FROM AUTHOR]

Plastic waste can exist naturally for hundreds of thousands of years and harm humans, animals, and the environment. In this study, the energy and exergy performances (absorbed energy, energy efficiency, absorbed exergy, and exergy efficiency) of LDPE (low-density polyethylene) plastic particles assisted by microwave heating based on the experimental data as affected by microwave power, feeding load, and chamber volume were evaluated and analyzed. The results showed that as the microwave power raised from 500 to 900 W, the feeding load changed from 10 to 30 g, and the chamber volume decreased from 200 to 100 ml, (a) the absorbed energy at the heating time of 60 min increased from 19.73 kJ, 5.84 kJ, and 22.71 kJ to 37.69 kJ; (b) the energy efficiency for the whole heating process increased from 1.10%, 0.32%, and 1.26% to 2.09%; (c) the absorbed exergy at the heating time of 60 min increased from 0.308, 0.091, and 0.091 to 0.724 kJ; and (d) the exergy efficiency for the whole heating process increased from 0.017, 0.005, and 0.023 to 0.040%, respectively. [ABSTRACT FROM AUTHOR]