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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]

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]

To enhance the overall performance of recompression supercritical carbon dioxide- (sCO2-) based systems, two new double-effect absorption reheat power cycles (DARPC) were developed in this study. These methods are based on the typical absorption power cycle (APC). For the proposed sCO2/DARPC systems, a parametric analysis of the thermodynamic and economic performances, as well as additional parametric optimisations, were performed quantitatively. The results indicate that replacing the APC subsystem with DARPC subsystems can enhance the total function of the sCO2 system even further, owing to the increased H2O vapour created in the separator and the reheating process, which adds to the greater net power output. Furthermore, compared to the DARPC2 subsystem, the DARPC1 subsystem may produce more H2O vapour from the generator and separator, resulting in an increase in net output power. When compared to a single sCO2 power cycle, multiobjective optimisations showed that the sCO2/DARPC1 and sCO2/DARPC2 systems could increase the exergy efficiency by 12.95% and 11.51% and decrease the total product unit cost by 9.67% and 8.37%, respectively. Furthermore, the sCO2/DARPC1 and sCO2/DARPC2 systems can achieve improvements in exergy efficiency of 4.95% and 3.61% and a total product unit cost of 4.52% and 3.15%, respectively, compared with the sCO2/APC system. [ABSTRACT FROM AUTHOR]

To assess the electricity cogeneration potential in the Minas Gerais cement industry with thermodynamic cycles is the main purpose of this study. The potential was estimated based on Minas Gerais cement sector data. The Kalina cycle, the organic Rankine cycle, and the conventional Rankine cycle were technically and economically assessed. The technical evaluation considered the thermodynamic modeling with optimization including the mass, energy, entropy, and exergy balances and the heat transfer calculations for heat exchangers. The economic evaluation considered the economic modeling including the calculation of electric power generated specific cost, the total investment, cash flow, and payback. The result shows that the greatest irreversibilities are concentrated in the turbines and evaporators. The Kalina cycle confirmed more generated power and exergetic efficiency, but in terms of thermal efficiency, the values were very similar between the cycles. The three cycles can cover more than 35% of the energy demand, which means a considerable reduction in cement manufacturing costs. All cycles reveal a payback value lower than 3 years, a considerable value of cash flow, and high competitiveness in the current tariff scenario. The electricity cogeneration potential in the Minas Gerais cement industry is near 100MW, and it is in the south-central region of Minas Gerais, where there is a greater population and energy demand concentration. This potential could save emissions of around 282,913 tCO2/year. [ABSTRACT FROM AUTHOR]

This study examines the optimal sizing of an off-grid hybrid system comprising solar photovoltaic (PV), rice husk-based biomass, and lead-acid battery for meeting the electric demand of a rural community. Considering a selected remote village in Bangladesh as a case study, the proposed optimized system is primarily compared with the diesel generator and the micro gas turbine (MGT)-based options in techno-economic and environmental terms. The potential social benefits, such as the employment creation and the improvement in the human development index in the locality, have been investigated in this study. Moreover, the impacts of operational greenhouse gas emissions on the human health damage and the surrounding ecosystem have been examined. Additionally, an exergy analysis of the hybrid system and the components has been carried out. Results indicate that in addition to being the environmentally preferable option, the proposed PV/biomass/battery system offers a lower cost of energy of 0.314 $/kWh compared to the MGT-based system (0.377 $/kWh). Although the diesel-based system offers a marginally better economy (9.55% less energy cost), it comes with the expense of probable damages to human health and the ecosystem worth of $15,211 and $6,608, respectively, making biomass the best option with no such damages. Exergy analysis reveals higher loss from PV than biomass and 13.09% system exergy efficiency. The assessment of the social indicators testifies to the potential of promoting the human development index from its current value and the formation of 1.41 jobs to as high as 15.15 full-time permanent jobs with the installation of hybrid systems in the community. [ABSTRACT FROM AUTHOR]

The research is aimed at investigating ammonia in a compression ignition internal combustion engine as a promising alternative fuel towards decarbonization. This study presents energy and exergy assessments of a low-power engine for three cases of fuel supply, diesel oil, biodiesel oil, and ammonia with pilot biodiesel oil, across the entire engine's range. While diesel or biodiesel was administered directly into the engine cylinder, the ammonia was delivered through port injection. The results show that the maximum thermal efficiency of 33.56% and exergy efficiency of 31.88% were found at 1800 rpm and 71% load for the diesel fuel system. For the biodiesel fuel system, the efficiencies were 32.72% and 30.93%, respectively, at 1800 rpm and 100% load, and for the ammonia with pilot biodiesel system, they were at 31.98% and 30.04%, respectively, for the same rpm and load. The exergy assessment indicates that exergy destruction, which accounts for the irreversibility of processes such as combustion and friction, is responsible for the greatest loss of useful energy. Optimizing these processes could significantly improve the engine's performance for all three fuel cases. This research found that ammonia could successfully substitute diesel or biodiesel fuel, as the engine's efficiency was comparable in all three tested scenarios; however, further research and optimization in terms of the ammonia-fueled engine emissions are required. [ABSTRACT FROM AUTHOR]

In this study, a coal-fired power plant with an integrated S-CO2 cycle is proposed to improve the system operational flexibility. To optimize the performance, a control strategy of variable load regulation is proposed. First, a dynamic mathematical model of the system is established based on the conservation of mass and energy principles, and then, dynamic verification of the model is carried out. In order to evaluate the performance of the proposed system, an exergy analysis is performed on the S-CO2 cycle, indicating that the exergy loss rate of the heater in the cycle is the highest. Finally, the dynamic performance of the system is simulated, and the dynamic response of the power generation load is analyzed. In addition, the system is evaluated based on the performance indicator of the flexibility of the power generation. It was found that the proposed system in this paper has a large load ramp rate which can quickly follow the load response. Meanwhile, compared with load downregulation, the system has greater potential for load upregulation. [ABSTRACT FROM AUTHOR]

NH3/CO2 cascade refrigeration system is recognized one of the most promising technologies in low-temperature application. In this paper, a NH3/CO2 cascade refrigeration system with subcooling in low-temperature circuit driven by recovery expansion work has been proposed. The aim of this study is to investigate the proposed cascade refrigeration system compared with conventional cascade refrigeration system. Mathematical models based on energy conservation and exergy balance are established. The selection of different refrigerants in auxiliary subcooling system is discussed. The effects of operating parameters such as the condensation temperature of the low-temperature circuit, evaporation temperature, and expander efficiency on system performance are evaluated. The results show that the coefficient of performance and exergy efficiency of the proposed system are about 7.56% and 7.98% higher than that of conventional cascade refrigeration system. The discharge temperature of NH3 compressor can be significantly reduced by 18.33%. The isentropic efficiency of the expander has a large impact on the system performance. [ABSTRACT FROM AUTHOR]

In this study, energy and exergy analyses of the closed‐cycle infrared (IR) convective walnut drying were performed. The effects of the combined heat transfer, product–source distance, and temperature–relative humidity (RH) control on the food quality of walnuts and performance were investigated. Experiments were conducted with and without an IR lamp. The temperature and RH of the drying air were set at 40°C and 20%, respectively. The distance between the product and the IR source was changed to 20 cm and 30 cm. The coefficient of performance values of the whole system changed between 1.56 and 2.34. Exergy efficiencies varied between 60.81% and 88.19% without IR and 72.73%–78.54% with IR. Energy and time savings increased by 14.7% and 26.1%, respectively, with using IR at a 20 cm distance compared with the convective system. The fatty acid composition of walnut samples and chemical properties of walnut samples such as total phenolic content, oil, ash, color, antioxidant activity, peroxide values, free fatty acid, conjugated trienes, conjugated dienes, saponification value, and iodine number parameters were analyzed. Food analysis results of all dried walnuts were in the acceptable range. As a result, energy and time savings were achieved with the desired food quality. Novelty impact statement: This application makes it possible to achieve the desired conditions with less energy. In this study, the effects of heat transfer mechanisms, the effect of using two mechanisms together, and the effects of the variables within each mechanism on the drying of walnuts were investigated. It has been observed that the addition of an infrared heat source with the right and suitable application shortens the drying time as well as saves energy. As a result of the food quality analysis, it was determined that all products dried without deteriorating the food quality. The closed‐cycle intermittent infrared convective drying system is recommended for industrial use. [ABSTRACT FROM AUTHOR]

Summary: In this study, several performance and thermodynamics metrics of a conceptual turboprop engine (C‐TPE) were computed at 50 (fifty) power settings. Based on these computations, these parameters were predicted by employing artificial neural networks (ANN) and long‐short term memory (LSTM) approaches. The obtained parametrically data were subjected to preprocessing for normalization. After determining model inputs to estimate the engine outputs, these data were introduced to ANN and LSTM. Then, the findings by two methods were compared with each other. In this context, fuel flow, air mass flow, exhaust velocity, compressor pressure ratio, turbine outlet temperature, and revolutions per minute (RPM) were selected as model inputs to estimate several metrics such as net thrust, specific fuel consumption (SFC), overall efficiency, exergy efficiency, and environmental effect factor (EEF) regarding the C‐TPE. For modeling of the mentioned metrics, 80% and 20% of the data were used for training and testing, respectively. According to the findings of energetic and exergetic computations, SFC value of the C‐TPE increases from 16.205 to 17.737 g/kNs whereas its overall efficiency varies from 23.63% to 22.31% owing to decrement in RPM. Moreover, exergy efficiency of C‐TPE remains between 23.93% and 26.2% whilst its EFF value resides between 2.66 and 3.05 throughout power settings. Finally, the modeling results indicate that coefficient of determination (R2) regarding overall efficiency of C‐TPE was found as 0.951867 with respect to the ANN model whereas it was calculated as 0.999906 with the proposed LSTM. It could be deduced that since LSTM is capable of providing lower the model error than the ANN for the same set of data, this method could be implemented to predict thermodynamics metrics of different kinds of gas turbine engine where obtaining data is limited. [ABSTRACT FROM AUTHOR]

Summary: The purpose of this research is to examine the performance assessment and multi‐objective optimization of a multigeneration energy systems that include power generation, cooling, and freshwater. The system under investigation is composed of a fuel cell, a multi‐effect desalination plant, an absorption chiller, a steam generator, and a thermoelectric generator. To do this, we employed thermodynamic modeling of the intended cycle to determine the optimal design points employing a genetic algorithm. Machine learning techniques have been utilized to lower the computing time and cost associated with optimization. The optimization of this cycle revealed that it is possible to increase the exergy and energy effectiveness by up to 72 and 79%, respectively while lowering the total cost rate to $ 9.23 per hour. [ABSTRACT FROM AUTHOR]

Summary: In this research, an integrated energy system for providing triple loads of an educational building has been modeled, analyzed, and optimized using artificial intelligence The use of different load supply patterns for the integrated system was optimized and evaluated from the point of view of exergy, economics, and environment. SketchUp, OpenStudio, and EnergyPlus are used to obtain the building loads, and the integrated system is dynamically modeled by the MATLAB software. The integrated system has been optimized based on different patterns, including monthly, seasonal, and two‐state constant loads compared with hourly dynamic loads using an artificial intelligence genetic algorithm. The results show that the dynamic load pattern gives the highest exergy efficiency and the lowest total cost rate. The exergy efficiency and total cost rate in this scenario are 58.78% and 5.022 $/h, respectively. Also, the CO2 emission index has reached 363.1 g/kWh. Due to the subsidized price of grid electricity, there is a tendency to use low‐capacity gas turbines and buy electricity from the grid for the dynamic model. The gas turbine capacity is 35.56 kW, and the system has purchased 242.4 MWh from the grid. Due to high heating loads, the capacity of the gas turbine significantly increases, and no electricity is purchased from the grid in the fixed‐load pattern. The highest capacity of the gas turbine is 161.6 kW, which is obtained by a seasonal fixed‐load pattern. Also, 994.9 MWh of electricity is sold to the grid in this mode. [ABSTRACT FROM AUTHOR]

An indirect type domestic hybrid solar dryer (ITDHSD) has been fabricated and its thermal performance, exergy, and drying kinetics of tomatoes slice were analyzed. Moisture in tomato slices was dried from 95% to 9% (wet basis) in 10 h of solar drying in ITDHSD during the winter season. Drying curve obtained was fitted with different existing empirical models and Prakash and Kumar model was found suitable for tomatoes drying in ITDHSD. Overall drying efficiency of the system was estimated as 41.05%. Furthermore, with variable mass flow rate, exergy efficiency values varied from 32.86% to 58.26%. Overall exergy efficiency was 46% during tomato drying experimentation. Various exergy sustainability indicators have been estimated in this study to observe improvement potential in the system. Improvement potential, waste exergy ratio, and sustainability index of the ITDHSD system was estimated in the range of 0.006966–0.065984, 0.41–0.67, and 1.55–2.39, respectively. Therefore, ITDHSD system provides a better option to domestic users for drying food crops in less duration and with no deterioration. This piece of work will be helpful for researchers in performing exergy analysis, drying kinetics, and performance assessment on hybrid solar dryers. Novelty impact statement: All available literature on tomato drying in a compact sized dryer lacked in evaluation of the exergy analysis of solar PV module used to run a fan. Moreover, an essential factor of equivalent moisture content is also neglected in the literature during calculation of moisture ratio, which cannot be neglected in drying high moisture crops in tropical areas with high relative humidity. In the present experimental study, a new hybrid solar dryer system design has been developed and fabricated for domestic users. [ABSTRACT FROM AUTHOR]

Summary: In this study, a solar‐based integrated system is designed and analyzed thermodynamically using the first‐ and second‐law approaches. The sustainable energy island concept is developed to meet the energy and commodity demands of emerging countries in a sustainable manner. The proposed system utilizes an energy island concept where solar energy is the main source and provides electricity, freshwater, and hydrogen by integrating a floating photovoltaic system, a parabolic through collector system, the Cu‐Cl cycle, a multi‐effect desalination unit, and a fuel cell unit in a sustainable fashion. The hydrogen‐based system is used to store energy in the chemical form to compensate for the time when the solar radiation is not available. A transient analysis is carried out to realistically determine the performance of the proposed system in a case study where Northern Cyprus is considered with its annual electricity demand. The proposed system averagely achieves an overall energy efficiency of 14.06% and an overall exergy efficiency of 14.61% while producing a total of 7.1 ton/h of hydrogen, a total of 115.4 ton/h of freshwater, and a total of 362.4 MWp of electricity, respectively. [ABSTRACT FROM AUTHOR]

Summary: In this study, a unique energy system integrated with an agrivoltaic plant, a biogas production and utilization facility, and a community‐based energy system is analyzed in order to fully cover the needs of electricity, biogas, heat, and cooling for a community. The bifacial photovoltaic modules with a high structure are considered in this design, where they cover the sugarcane field as the agrivoltaic system. Both sugarcane and cow manure are considered and used to generate biogas. An integrated energy system is proposed to meet the electricity, heating, and cooling requirements of a community in a case study. The capacities of the components are determined according to a community load selected for a case study with more than 34 000 people living in Nakhon Ratchasima, Thailand. A biogas‐based combined cycle with two stages of the Rankine cycle, as well as a bifacial photovoltaic‐based system, are used to generate electricity. The excess heat is recovered and used to cover the heating loads of the community for greenhouse and food dryer, as well as in a lithium bromide absorption refrigeration cycle to provide cooling. The first and second laws of thermodynamics are used with the mass, energy, entropy, and exergy balance equations to analyze and evaluate the system. A time‐dependent analysis is carried out to provide more insightful details about the system for each hour throughout the whole year. The experimental data for the biogas production system and actual meteorological data are considered with commercially available component and unit specifications to provide more realistic results. An 8 MWp of PV plant with 415 MWp of a biogas power plant as well as 105 MWp of high‐ and low‐pressure steam turbines can meet 100% of 92 GWh nonthermal electricity, 63 GWh cooling, and 13 GWh heating loads in a year. The overall energy and exergy efficiencies of the overall system are found to be 33.64% and 22.96% under average ambient conditions and average load requirements. [ABSTRACT FROM AUTHOR]

In this investigation, energy and exergy analysis of a hybrid infrared‐convective (IR‐CV) dryer is presented for drying cantaloupe slices. The experiments were performed at three temperature levels (40, 55, and 70°C), one level of air velocity (0.5 m/s), and three IR powers (250, 500, and 750 W). The relationships between the input process parameters (IR power, input air temperature, and drying time) and the thermodynamic properties of the dried product (moisture ratio, drying rate, energy efficiency, exergy efficiency, and exergy loss) were modeled by implementing the artificial neural network (ANN) and ANFIS. Results indicated that high IR power and air temperature can shorten the drying time, meanwhile increasing the energy efficiency. Based on the obtained results, input air temperature and IR power highly affect the exergy efficiency. The highest exergy efficiency was obtained at the input air temperature of 70°C and IR power of 750 W. The exergy loss was increased by increasing both parameters of the air temperature and IR power. Models developed using ANN and ANFIS indicated that the ANFIS model predicted the moisture ratio, energy efficiency, and exergy loss better than the ANN model, as it estimated these thermodynamic parameters at a higher regression coefficient (>0.9889) than ANN (0.9850), while, the accuracy of ANN model for predicting drying rate and exergy efficiency was better than ANFIS. Novelty impact statement: In this study, the effects of both different infrared powers (250, 500, and 750 W) and air temperature (40, 55, and 70°C) on drying kinetics, energy, and exergy of cantaloupe slices during the drying process were investigated. The prediction model of cantaloupe slice moisture ratio, energy, and exergy in the infrared hot air drying process was established based on artificial neural network and adaptive neuro‐fuzzy inference system. Artificial neural network and adaptive neuro‐fuzzy inference system model predictions agreed well with testing data sets and they could be useful for understanding and controlling the factors affecting drying behaviors. [ABSTRACT FROM AUTHOR]

Summary: For grid‐scale intermittent electricity storage, liquid air energy storage (LAES) is considered to be one of the most promising technologies for storing renewable energy. In this study, a steady‐state process model was developed for an LAES, by combining a Linde liquefaction process and an open Rankine power cycle. To investigate the system performance and achieve global optimization, a single‐factor analysis approach and multifactor genetic algorithm (GA) optimization model were built using MATLAB software. The effects of the charging pressure, storage pressure, discharging pressure, and isentropic efficiency of the compressor/turbine on the LAES performance parameters, such as the inlet temperature of the Joule–Thomson valve, round‐trip efficiency (RTE), liquefaction ratio (LR), and power consumptions in the compressor, cryo‐pump, and turbine, were investigated. Subsequently, the optimal conditions were obtained using the GA optimization method to achieve the optimal performance of the LAES. The results showed that the charging pressure, discharging pressure, and isentropic efficiencies of the compressor and turbine had significant effects on the RTE; an increase in the discharging pressure resulted in an improved expansion power output; the GA optimization could achieve RTE, LR, the system energy storage and recovery exergy efficiencies of 53.33%, 86.96%, 81.00%, and 78.16%; the power consumption in the compressor of GA optimization was 10.02% maximum saving. The proposed optimization method can be used to further explore the global optimization of cryogenic energy storage systems, such as different‐layout LAES systems and different cryogenic liquefaction media energy storage systems. [ABSTRACT FROM AUTHOR]

Summary: The use of CO2 as a refrigerant has become a trend in the development of the refrigeration industry. Refinement of new layout and improvement of cycle performance remains a major research direction, which coupling ejector and internal heat exchanger with the transcritical CO2 cycle is a popular method. In this paper, the issue of the effect of different positions of the internal heat exchanger on the dual‐ejector transcritical CO2 refrigeration cycle is discussed. The dual‐ejector cycle is evaluated both thermodynamically and economically by means of multi‐parameter optimization, which is compared with conventional two‐stage transcritical CO2 refrigeration cycle. The obtained results show that the COP of the dual‐ejector transcritical CO2 refrigeration cycle is on average about 42% higher than that of the conventional two‐stage transcritical CO2 refrigeration cycle. Adding internal heat exchanger at different locations cannot improve the performance of dual‐ejector transcritical CO2 refrigeration cycle system in low‐temperature refrigeration. In addition, the exergy and economic analysis shows that the dual‐ejector transcritical CO2 refrigeration cycle has better exergy efficiency, and the increase of internal heat exchanger is an unfavorable exergy efficiency. The exergy destruction rate and the total cost of the dual‐ejector system are on average 58% and 19% lower than that of the conventional cycle, respectively. At the same time, the addition of internal heat exchanger has very little impact on the total system cost. [ABSTRACT FROM AUTHOR]

Summary: This study presents a new system for solar power, which is generated through a solar power tower with a molten salt cycle. To increase the consumption of energy losses, besides the closed supercritical carbon dioxide (sCO2) Brayton cycle, a liquid natural gas (LNG) open‐cycle was used as a heat sink alongside a cascade organic Rankine cycle with the capability of working at low temperatures. LNG is implemented for a solid oxide fuel cell input, after cooling down the power generation systems and power generation. Besides the economic and thermodynamic analysis, destruction of exergy has been controlled and parametric studies are performed to investigate the influence of relative factors on the performance of the system. To optimize the system, a genetics algorithm has been employed by considering two reciprocal objective functions of the total cost rate and the exergy efficiency. The results of multi‐objective optimization show that the optimized point has a total product cost rate of $115.3/h and an exergy efficiency of 71%. Furthermore, exergy analysis shows that the molten salt heat exchangers and the LNG heat exchangers have the maximum rates of irreversibility and must be taken into consideration as a major priority for optimization. [ABSTRACT FROM AUTHOR]

In the present work, the thermal and exergy efficiency of the equilateral triangular duct solar air heater is analytically investigated and its performance is improved by attaching an inclined wire rib over the absorber surface. Using triangular ducts improves the operating flow conditions up to the Reynolds number of 35000. The thermal model of solar air heater is solved by using an iterative procedure by code developed in MATLAB. The analysis considers the roughness parameters that roughness pitch (P)-to-height (e) ratio (P/e) of 4 to 16, roughness height (e)-to-hydraulic diameter (Dh) ratio (e/Dh) of 0.021 to 0.043, and rib inclination angle (α) of 30 to 75°. While increasing the Reynolds number from 2000 to 35000, the inclined rib roughened triangular duct solar air heater thermal performance is increased and attains the maximum value of 83.61% and the effective thermal efficiency of 80.26%. The maximum exergy efficiency of 2.62% is obtained at the Reynolds number value of 1864. It improves the thermal performance by 14.2% as compared with the rectangular rib roughened triangular duct solar air heater. The optimum value of roughness parameters is P/e of 12, e/D of 0.042, and α of 75°. The air heater is useable to attain the temperature rise parameter ranges from 0.001 to 0.03 K·m2/W. [ABSTRACT FROM AUTHOR]

Excessive heat losses and water consumption in cooling units are significant constraints restricting the application circumstances and performances for the SCO2 Brayton cycle, and the heat exchange capacity in the precooler (PRC) is typically 1.5 times that of power generation. Therefore, this research offers a high-integrated combined power/cooling system in which two waste heat exchangers (WHEs) and a rectifier (RET) are used instead of the PRC to achieve 100% exhaust heat recovery. Each component's energy and exergy models are developed, and the operational characteristics, coupling relationships, and exergy destruction distribution are examined. Results indicate that, when compared to the Brayton cycle, the thermal and exergy efficiency is considerably increased, and the concentration difference and WHE1 pitch point difference have significant influences on system performance. Further exergoeconomic and optimization analysis reveals that the superior exergy case is mostly recommended for relevant thermal and exergy efficiency increasing rates of 13.7% and 9.17%, respectively, and the unit cost is 81.33% that of the base case. Turbine 1 (TUR1) and main compressor (MCP) are the first and second highest cost rates, respectively, and RET and generator (GEN) account for roughly 34% exergy destruction rate and 20% exergy destruction cost rate, respectively. In addition, reducing heat transfer differences in relevant equipment can further promote system performance. [ABSTRACT FROM AUTHOR]

Thermal photovoltaic systems are used to harness solar energy to generate electricity and thermal at the same time. In this technology, electrical efficiency is very low compared to thermal efficiency; as the cell surface temperature rises, the electrical efficiency decreases, so one of the ways to achieve high efficiency is exergy analysis. Exergy analysis of a process or system shows how much of the ability to perform the work or input exergy has been consumed by that process or system. In this research, an ordinary thermal photovoltaic panel with air cooling has been examined for exergy. To do this, it has identified the effective performance variables from a mechanical point of view, which are inlet air temperature, inlet air flow, and length (number of modules that are connected in series). The effect of changing each of the variables based on Saveh weather conditions has been simulated using MATLAB software. The results show that the exergy efficiency of the panel decreases with the inlet air temperature increasing. It was also observed that the optimal airflow is 0012 (kg/s) and will have the highest efficiency per 8.8 m length. [ABSTRACT FROM AUTHOR]

Summary: To effectively utilize the exhaust heat of high‐temperature proton exchange membrane fuel cells (HT‐PEMFCs) for cooling, a novel triple‐cycle system model mainly including a HT‐PEMFC, thermoelectric generator (TEG), and thermally regenerative electrochemical refrigerator (TRER) is theoretically formulated. The TEG activated by the HT‐PEMFC exhaust heat is used to drive the TRER for cooling. Considering irreversible losses in the HT‐PEMFC, TEG, and TRER and among these subsystems, mathematical formulas of the energetic and exergetic performance indexes are obtained. Calculation results show that compared with a sole HT‐PEMFC system, the equivalent power density, energetic efficiency, and exergetic efficiency for the triple‐cycle system increase by 16.0%, 12.6%, and 12.7%, respectively. The exergy destruction rate density reduces by 1.0%. Finally, sensitivity analysis of seven key parameters is conducted. This study can provide a valuable guide for the design of actual triple‐cycle systems based on HT‐PEMFCs for power and cooling cogeneration. [ABSTRACT FROM AUTHOR]

Summary: Research on thermoelectric geometry optimization has focused on stand‐alone thermoelectric devices utilizing energy analysis. This paper considers the multi‐parameter optimization of a solar‐powered thermoelectric generator using exergy analysis since it is more comprehensive than energy analysis. Results indicate that the energy and exergy efficiencies are minimally affected by very high optical concentration ratio values. Also, for achieving maximum performance, larger thermoelectric leg cross‐sectional area to length ratios should be used, the load resistance connected must be kept at an optimum value of 0.06 Ω, and an optimal hot junction temperature of 489.8 K are required to obtain maximum performance from the device. Finally, the thermoelement area to length ratio is increased by 10% for maximum system performance. [ABSTRACT FROM AUTHOR]

Summary: In this study, a multicriteria optimization is developed for a hybrid building integrated photovoltaic/thermal (BIPVT) system with a sensible rotary heat exchanger (SRHX) for both heating and cooling purposes. The BIPVT system is considered with and without considering the glass cover. Both the heat and electricity produced by the BIPVT‐SRHX system are determined according to the energy and exergy phenomena. The objective functions aimed to be maximized are the annual total amount of generated energy and exergy. The length and depth of SRHX, geometrical parameters of PV modules, and the air mass flow rate are the parameters considered in the optimization. The results reveal a high amount of produced energy for the optimized design; however, the total amount of generated exergy is low. The system with the glass cover shows a higher amount of gained heat and less generated electricity compared with the system without the glass cover. The total energy produced by the system with and without the glass cover is about 227 and 220 MWh, respectively, and the total produced exergy by the systems with and without the glass cover is 1207 and 1585 kWh for the optimized design, respectively. [ABSTRACT FROM AUTHOR]

Summary: This review paper focuses on converting plastic wastes into clean hydrogen via gasification for better sustainability. In this regard, various aspects of hydrogen production from plastic wastes are discussed and comparatively evaluated, including the state‐of‐the‐art and comparative evaluation, environmental and economical dimensions, global warming aspects, policies and strategies, a case study including energetic and exergetic performance evaluations, challenges and opportunities, and future directions possibly in the area. Additionally, this paper outlines what contributions it makes to the current literature about hydrogen production from plastic wastes by using gasification technologies. Moreover, this paper provides a detailed case study indicating exergetic sustainability aspects for hydrogen production from plastic wastes by applying plasma gasification whose data are taken from the literature. As a result of this case study, some exergetic sustainability indicators are studied for evaluation and comparison purposes. The exergetic sustainability index is found to be decreasing from 0.77 to 0.41 with the fact that exergetic efficiency drops from 0.43 to 0.28 while the environmental impact factor rises from 1.29 to 2.41 with the increase of waste exergy ratio from 0.56 to 0.70. Furthermore, plasma co‐gasification can be recommended as an environmentally‐benign solution for clean hydrogen production from plastic wastes. Highlights: Plastic wastes is an important source of hydrogen.Gasification can efficiently be deployed for hydrogen production from plastic wastes.In order to evaluate potential gasification techniques, energetic, economic, environmental, and sustainability aspects should be considered.Plasma gasification appears to be more efficient and effective solution over other methods for higher amount of hydrogen production from plastic wastes. [ABSTRACT FROM AUTHOR]

Summary: In this study, a novel high‐performance engine cycle composed of 5 processes and including constant temperature process has been developed by using novel numerical methods and compared with the classical dual cycle. The results of the classical thermodynamic model demonstrated that the proposed cycle which has a constant temperature process is better in terms of thermal efficiency and dimensionless net work compared to the classical dual cycle. After the validation of superiority of the developed cycle over the classical dual cycle, performance investigations of the novel cycle engine have been carried out in terms of power, power density, destructed exergy, thermal efficiency, ecological coefficient of performance, effective ecological power density by developing a novel fuel‐air cycle model. The influences of design and operational parameters such as cut‐off ratio, compression ratio, cycle temperature ratio, equivalence ratio, engine speed, stroke length, cylinder bore, cylinder wall temperature, air intake temperature, pressure ratio, on the performance specifications have been numerically derived. [ABSTRACT FROM AUTHOR]

In this paper, various eco-friendly refrigerant mixtures R430A, R436A, R436B, R435A, and R510A used in vapour compression refrigeration systems are considered for this study. All of them have zero ODP and very low GWP. On the basis of exergy features, the efficiency of various working fluids in vapour compression refrigeration cycles was compared. The exergy efficiency of mixtures is evaluated for various evaporating temperatures ranging from -40°C to -5°C at a constant condensation temperature of 45°C. The variation of exergy is also analyzed for various condensation temperatures ranging from 25°C to 60°C at a constant evaporating temperature of -10°C. The exergy losses in various components are computed and presented in Grassmann diagrams for a cooling load of 1 kW. The results indicate that all the investigated alternative refrigerant mixtures have higher exergy efficiency than R134A. The maximum exergy performance is 39.72% observed for the mixture R435A at an evaporation temperature of -30°C, and this value is 9.89% higher than that of R134a.The results also show that the highest and lowest exergy losses have occurred in the compressor and evaporator. [ABSTRACT FROM AUTHOR]

Summary: Metallic solder based PCMs possess higher thermal conductivities, larger storage masses and exhibit lower subcooling effects compared to their organic or inorganic counterparts. It is thus justified to investigate their potential usage for medium temperature applications. These solders are relatively expensive and can be combined with cheaper PCMs in cascaded storage systems which are more thermodynamically efficient compared to single PCM systems as reported recently. The aim of the research is thus to compare two packed bed storage systems during discharging cycles using eutectic solder (Sn63/Pb37), that is widely available worldwide. The single PCM system (40 capsules) consists of encapsulated spheres of eutectic solder, whereas the second cascaded system consists of encapsulated spheres of eutectic solder and erythritol in an equal storage ratio in the tank. For the cascaded system, the eutectic solder capsules are placed at the top and erythritol at the bottom of the storage tank (20 capsules at the top and 20 at the bottom). The effect of the discharging flow‐rates of 4 mL/s, 6 mL/s and 8 mL/s is investigated in relation to the temperature profiles, energy rates and exergy rates. Increasing the flow‐rate, increases heat transfer rate thus shortening the discharging time as well as increasing thermal profile reversals during discharging. The peak energy and exergy rates increase with the increase in the flow‐rate for the two storage systems. The single PCM system shows slightly higher average energy and exergy rates compared to the cascaded system possibly due to its higher thermal conductivity. The cascaded PCM system shows higher average stratification numbers at all the flow rates considered. The non‐cascaded system exhibited slightly higher exergy recovery efficiencies compared to the cascaded PCM system possibly due to its higher thermal conductivity at all flow‐rates considered. The effect of the initial discharging temperature is also investigated with a discharging flow‐rate of 6 mL/s after charging with set heater temperatures of 260°C, 280°C and 300°C, respectively. Comparable thermal profiles are seen for both systems for the three set temperatures; however, the single PCM system shows slightly higher storage temperatures. The single PCM shows slightly higher but comparable peak and average discharging energy rates compared to the cascaded system. The exergy rates for the two systems are also comparable. However, the cascaded system shows slightly higher exergy rate values for the lowest set temperature whereas the single PCM system shows slightly higher exergy rate values for the other two set temperatures. Energy and exergy rates are almost independent of the initial storage tank temperatures induced by different set charging temperatures. The average stratification number shows no correlation with set temperature for both storage systems. The cascaded system shows slightly higher average stratification numbers at different set temperatures. Exergy recovery efficiencies for different set heater temperatures are comparable for the two storage systems and vary only marginally with the increase in the set temperature. Overall, the effect of the flow‐rate is more pronounced than the effect of the set heater temperature. [ABSTRACT FROM AUTHOR]

Energy, exergy and economic analysis are proposed herein to evaluate regasification systems in Floating Storage Regasification Units (FSRUs). Three regasification systems typical in these types of vessels are considered: seawater system, open loop propane system and closed loop water-glycol system. The energy and exergy analyses were performed using the Engineering Equation Solver (EES), while Suite AspenONE programmes were used for the economic assessment. The exergy analysis provides a better understanding of the components of physical exergy (thermal and mechanical exergy) in order to define an exergy efficiency applicable to any liquefied natural gas (LNG) regasification system or FSRU. The results obtained prove the seawater regasification system to be most efficient from an energy and exergy standpoint. The specific energy consumption and exergy efficiency for this system are 227.33 kJ/kg and 50.00%, respectively. On the other hand, the open loop propane regasification system is most cost-effective for an LNG price between 1.32 and 11 USD/MMBtu. The vast amounts of destroyed exergy in the regasification process of current systems was also demonstrated and hence the need to develop new, more efficient configurations that could exploit the cold energy of LNG. [ABSTRACT FROM AUTHOR]

In this paper, the physical parameters of the absorber pipe of a linear parabolic collector have been investigated. The types of solar collectors, specifically the linear parabolic collector, have been comprehensively studied. Then, the mathematical model of heat transfer in the absorber pipe of the collector has been presented based on valid references. Numerical solutions of the equations related to the absorber pipe were performed by MATLAB software, and the effects of the physical parameters of the absorber pipe on its efficiency were investigated. The results show that increasing the length of the absorber pipe causes a nonlinear decrease in the efficiency of the absorber pipe. One of the important results is the increase in fluid temperature due to the increase in the diameter of the adsorbent tube, which increases the diameter of the fluid temperature by 60 K, in which the parameter increases the efficiency by 0.38%. [ABSTRACT FROM AUTHOR]

Summary: A novel efficient and entirely green hybrid energy conversion system comprising compressed air energy storage and Kalina KCS11 is proposed for peak shaving application and grid stability. The use of high‐temperature thermal energy storage as a replacement for the traditional combustion chamber and a Kalina KCS11 with clean working fluid aims to minimize greenhouse gas emissions while adequately addressing intermittency and electricity curtailment of power grids with high penetration of renewable sources. The proposed system is comprehensively analyzed from the energy, exergy, and economic viewpoints. The thermodynamic simulation results indicate that the air turbine and pressure regulating valve have, respectively, 595.5 and 477.5 kW exergy destruction, accounting for around 40% of total exergy destruction. In addition, employing a KCS11 cycle recovers 57.95% of the heat dissipated in the CAES outlet. Accordingly, the proposed hybrid CAES‐KCS11 system has round trip energetic and exergetic efficiencies of 52.97% and 46.28%, respectively. The economic analysis reveals that along with environmental benefits, it has a reasonable payback time of around 3.69 years. Moreover, a total benefit of 740 000 $ is gained during the service year of the system. The hybrid system is found to be more efficient compared to a stand‐alone high‐temperature hybrid CAES system. [ABSTRACT FROM AUTHOR]

Summary: The utilization of solar energy to generate electricity, cooling, and freshwater in remote areas in a sustainable way still poses lots of challenges to researchers. The aim of the current study is to design a new solar‐operated trigeneration system to produce electricity, cooling, and fresh water using parabolic trough collectors in remote areas. Electric power is generated by using Organic Rankine Cycle, and cooling and fresh water (using freezing desalination technique) are obtained by two‐stage NH3–H2O vapor absorption system run by solar energy. Simulation results show that for PTC arrays of 200 m2, an electrical output obtained is 3.3 kW, cooling rate is 20.4 kW, and mass flow rate of freshwater produced is 36 kg/h for an average solar irradiation of 0.7 kW/m2. Furthermore, sensitivity analysis is conducted by varying the parameter like solar irradiation, evaporator temperature, seawater inlet temperature, etc. and their effect on performance characteristics of the overall setup is investigated. [ABSTRACT FROM AUTHOR]

Summary: This paper proposes the design of a new solar power‐based multigeneration system for generating hydrogen, ammonia, methane, and other beneficial outputs. This combined plant consists of the solar plant, Rankine cycle, organic Rankine cycle, single‐effect absorption with ejector, carbon dioxide capture, hydrogen, ammonia, methane, drying, hot, and freshwater generation plants. The overall plant is investigated utilizing the Engineering Equation Solver software. The energy and exergy efficiencies of the integrated plant are computed as 0.6689 and 0.6227. In addition, the largest exergy destructions in the system are 6924 and 4037 kW, which occur at the Rankine cycle and solar power cycle, respectively. Moreover, the thermodynamic performance of the combined plant is investigated through parametric works and the impacts of plant working conditions on the plant efficiencies are evaluated. [ABSTRACT FROM AUTHOR]

Summary: Nowadays, the hybrid system's coupling of concentrated photovoltaic (CPV) and concentrated thermoelectric (CTE) devices is among the most competitive solutions for exploiting the maximum solar radiation. In this paper, a new concept of this hybrid system integrating a cooling system is investigated for the first time. In particular, the impact of such cooling on the global efficiency of this hybrid system is studied. The effect of the static and dynamic cooling system is evaluated, in which the water and nanofluid based on Cu, Al, and Fe nanoparticles is used for perform cooling, to produce the maximum electricity. A detailed analysis using state‐of‐the‐art thermal transfer calculations and the standard Matlab/Simulink Package has demonstrated that cooling of solar cells is crucial to optimize the CPV system efficiency. Our major finding showed significant superiority of the cooling system‐based nanofluid compared to water. Indeed, at a concentration equal to 10, the gain of the CPV system efficiency under cooling is 5.68% and 2% by Cu and Al nanoparticle‐based nanofluid, respectively, while the water‐cooling is inferior, and the exergy efficiency of the CPV‐CTE can be enhanced to 19% under cooling compared to the efficiency without cooling which is equal to zero. In addition, the cooling system in our model has an interesting advantage that the hot outgoing fluid resulting from the cooling process of the CPV will react as a heat source for CTE during the night to generate the energy without affecting the stored reserve of electricity during the day. Consequently, extending the autonomy of this hybrid system coupling CPV and the CTE to generate energy. Highlights: A new hybrid system CPV‐CTE integrating a cooling system is investigated for the first time.The effect of static and dynamic cooling systems by the fluid and nanofluid is evaluated.The state‐of‐the‐art thermal transfer calculations and numerical method is used.The heat transfer is modeled in a hybrid system under cooling. [ABSTRACT FROM AUTHOR]

Summary: In this article, an exergo‐economic study of an experimental lab‐scale integrated copper‐chlorine (Cu‐Cl) cycle of hydrogen production is conducted. The analysis is performed based on a specific exergy costing (SPECO) method to determine the influences of various design criteria on the costs and then identify possible improvements for more cost effective approaches. The article includes an exergy analysis, economic study, exergy costing and exergo‐economic evaluation. Also, a scale‐up analysis is performed to predict the cost of a larger scale facility of 1000 kg per day of hydrogen production. The results of the exergo‐economic and scale‐up analysis are expected to assist in the design, optimization and improvement of a scaled‐up Cu‐Cl thermochemical cycle. Furthermore, the results of this study show that for a large‐scale Cu‐Cl cycle plant with a capacity of 1000 kg/day H2, the cost of hydrogen production, excluding the treatment of side reactions, is predicted at about 3.91 $/kg H2. [ABSTRACT FROM AUTHOR]

Summary: Adiabatic compressed air energy storage system (ACAES) has a natural advantage on trigeneration combined cooling, heating and power. A dynamic model coupled with exergy calculation is developed and the charging strategy for trigenerative application is focused on. The dynamic characteristic of ACAES is performed and the effects of charging mode, number of compression stages and thermal energy storage on the characteristic of trigenerative application are obtained. The sliding‐pressure charging mode is suggested for the trigeneration due to 3.92% higher exergy efficiency than that of constant‐pressure charging mode. Asymmetrical arrangement of ACAES with more compression stages is efficient for its trigenerative application especially increasing heating and cooling supplies with 2.9% exergy efficiency improvement. Furthermore, changing mass flow rate of thermal energy storage medium (ie, water) shows an outstanding ability to vary the cooling, heating, and power supply ratios in a very wide range. Besides, the economic analysis is carried out which addresses the obvious economic improvement by trigenerative application of ACAES. Accordingly, joint regulation of compression stages and water mass flow rate is suggested to be an efficient and economic approach to adjust the distribution of cooling, heating and electricity supplies according to the user's demand. [ABSTRACT FROM AUTHOR]

Summary: In the conventional coal power plants, substantial amount of energy loss takes place through condenser, fluegas and coal mills rejection. Separate studies based on these waste heat resources with single Kalina Cycle System (KCS) in each case shows improvement in plant efficiency with additional power generation but the present study shows the combined waste heat utilization of condenser, fluegas and coal mill rejection in a 500MWe subcritical (SubC) coal‐fired thermal power plant using single solar assisted KCS. The modified configuration reduces the system complexity, space requirement and irreversibility by using less number of equipments. The system is thermodynamically modelled by MS‐Excel macros for analysing the system performance at different conditions. The study shows that an additional electricity generation of about 10 738.42 kW increases the plant net energy and exergy efficiencies by about 0.852% and 0.761% points, respectively resulting in reduction of CO2 emission by about 8.78 tons per hour at 55 K degree of solar heating. About 55.75 K and 7.20 K are the optimum Log Mean Temperature Difference (LMTD) values of the evaporator and steam condenser, respectively that yields the maximum net energy output economically at 12.60 bar operating pressure. Effect of solar energy variation on system performance is also carried out by varying the degree of solar heating. Economic analysis of the proposed system is also performed by considering 25 years of equipment life and a loan interest of about 14%. The cost of electricity and simple payback period (SPP) of solar assisted KCS are about Rs. 0.83/kWh and 1.19 years, respectively, at 55 K degree of solar heating (optimum). The study further shows that the levelized cost of excess electricity generation by solar heater is lower than the standalone solar thermal power plant by about 53.78%. [ABSTRACT FROM AUTHOR]

Summary: A novel solar‐based compressed air energy storage system is developed and analyzed in this paper. The integrated system includes a multi‐stage air compression unit, thermal oil loop, multi‐stage gas turbine unit, high‐temperature molten salt‐based solar power tower unit, liquefied air power cycle, thermoelectric generator, and liquefied natural gas (LNG) regasification unit. A eutectic mixture of carbonate salt is used for thermal energy storage in the solar subsystem. Energy, exergy, and economic analyses are performed to evaluate the performance of the proposed system. A parametric study investigates the effects of important parameters on the performance of the integrated system. The proposed system stores 356 MWh of grid electricity during the charging mode. Considering all the available energy sources, the energy output of the integrated system is 797.6 MWh. Energy and exergy efficiencies of the integrated system are 55.3% and 46.4%, respectively. The results show that the highest contributor to the overall exergy destruction rate of the integrated system is the combustion chamber unit. Finally, levelized cost of electricity is evaluated as ¢12.4/kWh. [ABSTRACT FROM AUTHOR]

Summary The aim of this work is to investigate a novel integrated cooling, heating, and power (CCHP) system with biomass gasification, solid oxide fuel cells (SOFC), micro‐gas turbine, and absorption chiller. The performance of this system is analyzed by mathematical models consisting of lumped models of SOFC and absorption chiller and one‐dimensional model of a downdraft biomass gasifier. Effects of main operating parameters such as moisture content of biomass, air flow rate in the gasifier, and temperature of fuel gas on the overall energy and exergy performance of CCHP system are evaluated. The net present value (NPV) method is used to analyze the economic prospects of this system. The results show that higher flow rate of air for the gasifier with lower moisture content of biomass are beneficial for the improvement of the output of cooling, heating, and power of CCHP, and, accordingly, the electrical efficiency as well as overall energy and exergy efficiency of CCHP rises. Increasing mass flow rate of air for the gasifier can increase exergy efficiency by 10%. Moisture content less than 0.2 could result in exergy efficiency greater than 45% and CCHP efficiency over 65%.The decrease of the exhaust gas temperature further boosts the production of cooling and heating of the CCHP system. Specifically, a 10% improvement of overall efficiency of CCHP is obtained when the exhaust gas temperature is reduced to 90°C. In this work, an electrical efficiency over 50%, exergy efficiency more than 40%, and CCHP efficiency up to 80% can be achieved. Economic assessment shows that the initial investment of SOFC is above 50%‐60% of the total investment of the CCHP and the payback period is about 7‐8 years. [ABSTRACT FROM AUTHOR]

Summary: A comprehensive review of thermodynamic cycles for the simultaneous production of power and cooling is presented. The study not only actualizes the bibliographic reviews previously realized by other authors regarding cycles such as Kalina, Goswami, or modifications of them. This review additionally includes an overview of hybrid cycles and other novel cycles reported in the literature. The hybrid cycles included in the study are systems integrated by two or three conventional cycles, mainly composed of Brayton, Rankine, and ORC for power generation; and compression, absorption, and ejector cycles for cooling production. The other novel cycles mentioned are thermodynamic cycles, which considerably differ from all the others. By using internal rectification, the Goswami cycle increased its efficiency by about 5%; however, by adding diverse components, as a condenser and a subcooler, the efficiency was significantly improved due to the considerable increase of the cooling production. Organic Rankine cycles integrating absorption refrigeration cycles are, in general, the most efficient hybrid cycles, reaching thermal efficiencies close to 40% for the simultaneous production of power and cooling. If a third output was provided, as heating or water distillation, the energy efficiencies were as high as 90%. The main problem with these systems is that, in general, they are too complex and costly because of the considerable number of components. The highest exergy destruction values are reported in solar collectors when used, followed by boilers or generators, and absorbers. The lower production costs were reported with systems integrating a Brayton cycle, an organic Rankine cycle, and an ejector‐cooling cycle. The disadvantage of these systems is that they need high operating temperatures. [ABSTRACT FROM AUTHOR]

Summary: In freshwater‐scarce coastal regions, increasing water demand has always been met via coupling thermal desalination systems with combined heat and power plants for many decades. These mature hybrid plants are known as cogeneration power and desalination plants (CPDP). Gas turbine (GT) driven CPDPs to suffer a performance drop in the summer months due to the high‐temperature ambient air intake which coincides with the season when power demand is highest. As a result, fuel consumption increases significantly to maintain these plants at full load conditions. At the expense of purified water, evaporative cooling (EC) has been proven to be a cost‐effective solution to combat the degradation in the plants' performance in the summer months. Several studies in the past propose the more complex waste heat or solar energy‐fired absorption refrigeration (AR) systems to combat this performance degradation. By performing an energy/exergy analysis and an hour‐by‐hour simulation on a conceptual plant representing an existing utility‐scale GT‐driven CPDP, this study analyzes the thermodynamic performance with and without EC and AR systems. Based on the simulation results, the power generated per GT unit decreases 0.65% for every 1°C rise in ambient air temperature. As a result, the plant's total fuel consumption increases by up to 12.4% relative to the design conditions to maintain the 100% power and water load. At the average summer conditions, integrating EC and AR systems increases the energy utilization factor of the plant by 5.89% and 9.11%, respectively. The plant's overall exergetic efficiency also increases by 5.96% and 6.73%, respectively. While EC systems increase the plant's annual in‐house water consumption by 32.4%, the annual total freshwater exports reduce by 0.151% only. Payback periods were calculated to be 1.84 and 5.70 years when integrating EC and AR systems, respectively and emissions savings ranged from 139 to 187 million kg of CO2 annually. [ABSTRACT FROM AUTHOR]

Examination of the Ohmic evaporation process in terms of electrical conductivity value and laws of thermodynamics is limited in the literature. In this study, the moisture content of the grape juice sample was concentrated from 5.75 kg water/kg Dry‐Matter (DM) to approximately 2 ± 0.3 kg water/kg DM by an ohmic evaporator. Evaporation process was applied in three different voltage gradients (16–24 V/cm) by Ohmic evaporator. The electrical conductivity value was found to be between 0.21 and 0.77 S/m during the heating process while it was between 0.77 and 1.01 S/m during the evaporation process. In addition, when evaluating this process concerning thermodynamic laws, it was stated that increasing voltage gradient had a positive effect on energy efficiency, exergy efficiency, and improvement potential values. To conclude, it was achieved that the ohmic heating‐assisted evaporation process could be used in the concentration of grape juice and an effective system with an average of 80% energy efficiency. Practical applications: As the ohmic heating process is known as a homogeneous, rapid, and efficient heating technique, its use in food applications is gradually increasing in recent years. Evaporation process is one of the preservation methods used especially in the fruit juice industry. An alternative evaporation method has been obtained by integrating the ohmic heating process into the evaporation process. It was determined that the voltage gradient used and foam formation were an effect on the electrical conductivity and performance analyses. It was determined that as the voltage gradient increased, the amount of water removed from the grape juice increased (kg/s) and the total processing time shortened. It is considered that this study may be a data source in the literature related to pilot and industrial‐scale production lines by determining electrical conductivity value during the evaporation of grape juice and investigating energy efficiencies. [ABSTRACT FROM AUTHOR]

Summary: The objective of the research is to discuss the issues, opportunities, and benefits of a combined heat and power system, including a micro gas turbine engine (M‐CHP) operated by natural gas, with an estimated sale price of $245 000 that produces 225 kW‐net of electrical power and a 209.8 kW‐net thermal power output in the industrial zone via thermodynamic indicators that help to measure the cost rate, the environmental/ecological effects, and sustainable growth. The ratio of useful energy output (electrical and heating) to the fuel energy for the M‐CHP is computed to be 70.2%. In addition, other indicators constituting the practical implications of the study, with a capacity to cause a positive change in fuel consumption and the amount of pollutants (electrical to heating ratio, efficiencies of exergy and improved exergy, fuel exergy depletion and productivity lacking ratios, improvement potential, cost rates and sustainability indexes) are detailed. The novelty of this work is the capability to serve as guide for similar systems with a detailed approach in performance and environmental assessment by prioritizing efficiency and fuel consumption. This investigation intends to establish a design for the opportunities and benefits that a thermodynamic approach provides to M‐CHP systems. [ABSTRACT FROM AUTHOR]

Summary: CO2 capture and storage(CCS) are required for coal‐fired power plants, which are major sources of anthropogenic CO2 emission. In this study, energy, exergy, environment, and economic (4E) analyses were performed for a 500‐MWe oxy‐coal ultra‐supercritical circulating fluidized‐bed (CFB) power plant with CO2 capture. The effect of the location of flue‐gas recirculation (FGR) on the 4E values was investigated for wet FGR (wFGR) at 170°C, dry FGR (dFGR) at 68°C, and 80% wet and 20% dry FGR (wdFGR). The net electricity efficiencies of the wFGR and dFGR power plants were 37% and 36%, respectively. The exergy loss was the largest in the combustor and boiler area, where process improvement was possible. The levelized cost of electricity was approximately 60 $/MWh. The return on investment was 6.7% and 6.1%/y for the wFGR and dFGR plants, respectively. The CO2 emission rate decreased by 90% (from 690 to 76 kg‐CO2/MWh) in the oxy‐coal power plants with CO2 capture. Relative to the wFGR, the dFGR was advantageous for preventing material corrosion because of the lower sulfur content in the FGR stream. For the wdFGR power plant, the process performance was intermediate, that is, between that of the wFGR plant and that of the dFGR plant. The study provided an effective tool for identifying the technological and economic effects of the FGR location for the oxy‐coal power plant with CCS via 4E analyses. [ABSTRACT FROM AUTHOR]

Summary: Chemical looping hydrogen generation (CLHG) is a hydrogen production process with broad prospects for its advantages of not requiring H2 purification process and direct CO2 capture. Presently, the research on the integrated system of CLHG focuses on the impact of integrated processes and operating variables on the overall energy efficiency and exergy efficiency of the system. However, the research on the matching relationship between quantity and quality in the process of energy conversion is insufficient, and the flow direction of exergy and the specific exergy destruction process for equipment are not clear. The integrated system of coal gasification (CG) and three reactors CLHG was established in this paper with a hydrogen production efficiency of 42.55% and system exergy efficiency of 52.98%. This paper studied the exergy flow direction and efficiency of the equipment in the system, providing the improved direction for the amelioration of the system; a detailed description was present on the change process of energy quality in each equipment with energy quality factor, and the concept of energy quality factor ratio was proposed as an evaluation tool for matching the quantity and quality of energy in the system. It is calculated that the ratio of energy quality factor of the integrated system of CG and CLHG is 0.944. By comparing with the energy quality ratio of the traditional CG hydrogen production system (0.896), it can be concluded that the integrated system of CG and CLHG has a better energy matching relationship. [ABSTRACT FROM AUTHOR]

Researches in many laboratories on solar still desalination are concerned with increasing efficiency using only solar energy. One of the techniques is the difference in the thickness of the glass cover of the distiller. In order to see the influence of this parameter on efficiency, three similar stills with three different glass coverings were investigated. The flow of heat goes through the cover, and higher glass temperature leads to solar still productivity becoming lower. This paper presents an optimization of glass thickness ( G t ) of a conventional solar still (CSS) in El Oued climate, Algeria. Based on the experimental results, the distilled water production rate, energy, and energy efficiency of the CSS have been discussed. The results showed that the suitable G t of the CSS was 3 mm. The distilled water of around 3.15, 2.02, and 1.13 kg was produced by the CSS at energy efficiency of 30.71, 19.02, and 11.44% with the G t of 3, 5, and 6 mm, respectively. The daily average exergy efficiency of 2.46, 1.38, and 0.84% was calculated for the CSS at G t of 3, 5, and 6 mm, respectively. [ABSTRACT FROM AUTHOR]

Summary: In the current investigation, a novel ejector‐enhanced heat pump system was presented and comprehensively evaluated using zeotropic mixtures. In the suggested plant, a booster was added to the conventional ejector‐enhanced system to expand its performance. Moreover, the suggested plant was modeled in a way to operate zeotropic mixtures, in order to maximize the productivity of the system. The plant was investigated with regard to energy, exergy, and thermoeconomic analyses to have a deep insight of the performance characteristics, that is, exergy efficiency, COP, and unit price of the product. To this end, a parametric evaluation was conducted to predict the performance characteristics of the plant by changing the value of different input variables. The results of exergy analysis indicated that the maximum exergy annihilation (7.784 kW) was associated with the ejector. The proposed system was also compared with a conventional system, and the findings unfolded that the COP of the proposed system surpassed the conventional system by up to 25%. Moreover, the outcomes of thermoeconomic analysis showed that the unit product cost of the proposed system is 133.596 $/GJ. The outcomes further demonstrated that the highest performance of the plant was concluded using R‐600/R‐143a mixture fluid with R‐600 mass fraction of 0.45. The sensitivity evaluation further indicated that, by enhancing the condenser temperature, exergetic efficiency and heating load increased while COP and unit cost of product decreased. Moreover, there was an optimum local point, in terms of exergetic efficiency (29.5%), when the booster pressure ratio is about 1.4. In addition, at the ejector pressure lift of 1.15, the exergetic efficiency was maximized locally. The heating load of the system, however, increased continually with increasing pressure lift. The proposed system showed a decent functionality with respect to thermodynamic and thermoeconomic criteria. [ABSTRACT FROM AUTHOR]

Summary: Although as an advanced energy utilization approach, the performance of combined cooling, heating, and power (CCHP) system is susceptible to its configuration and operation strategy. Energy price will also affect the system performance indirectly by influencing the system's design scheme. In this paper, a linear programming (LP) based optimization model is formulated to obtain the optimal design scheme that minimizes the annual total cost of typical CCHP systems, and a comprehensive assessment framework involving economic, energy, exergy, and ecological (4E) aspects is established to assess the system performance roundly. Taking a CCHP project in Xian, China as the specific case, the design and assessment of the CCHP system are completed and sensitivity analyses for two steps, namely configuration design step and operation strategy design step, are carried out to explore the impacts of energy price fluctuation on the design scheme and performance of the system. In this process, the coupling relationship between the purchase price of natural gas and electricity are considered, and as a special form of energy price, the effects of the feed‐in tariff are also discussed. The results show that the performance of the CCHP system is superior to the separate generation (SG) system in 4E aspects, reducing the running and maintenance cost, primary energy consumption, and greenhouse gas emissions by 18.63%, 24.77%, and 31.88%, respectively, and promoting the exergy efficiency by 30.87%. The feed‐in tariff lower than or equal to the electricity price will have positive effects on the overall performance of the CCHP system, and a lower natural gas price and a higher electricity price are benefit for playing the advantages of the system. [ABSTRACT FROM AUTHOR]

Summary: The present study investigates the performance of a multi‐generation plant by integrating a parabolic dish solar collector to a steam turbine and absorption chiller producing electricity and process heat and cooling. Thermodynamic modeling of the proposed solar dish integrated multi‐generation plant is conducted using engineering equation solver to investigate the effect of certain operating parameters on the performance of the integrated system. The performance of the solar integrated plant is evaluated and compared using three different heat transfer fluids, namely, supercritical carbon dioxide, pressurized water, and Therminol‐VPI. The useful heat gain by collector is utilized to drive a Rankine cycle to evaluate the network output, rate of process heat, cooling capacity, overall energetic, and exergetic efficiencies as well as coefficient of performance. The results show that water is an efficient working fluid up to a temperature of 550 K, while Therminol‐VPI performs better at elevated temperatures (630 K and above). Higher integrated efficiencies are linked with the lower inlet temperature and higher mass flow rates. The integrated system using pressurized water as a heat transfer fluid is capable of producing 1278 and 832 kW of power output and process heat, respectively, from input source of almost 6121 kW indicating overall energy and exergy efficiencies of 34.5% and 37.10%, respectively. Furthermore, multi‐generation plant is evaluated to assess the exergy destruction rate and steam boiler is witnessed to have the major contribution of this loss followed by the turbine. The exergo‐environmental analysis is carried out to evaluate the impact of the system on its surroundings. Exergo‐environmental impact index, impact factor, impact coefficient, and impact improvement are evaluated against increase in the inlet temperature of the collector. The single‐effect absorption cycle is observed to have the energetic and exergetic coefficient of performances of 0.86 and 0.422, for sCO2 operating system, respectively, with a cooling load of 228 kW. [ABSTRACT FROM AUTHOR]