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Abstract Geothermal energy is an abundant natural resource in many regions around the world. However, in some areas, the temperature of the geothermal energy resource is too low to be efficiently harvested. Organic Rankine cycles (ORCs) are known for recovering heat from low-temperature resources and generating electricity. Furthermore, half-effect absorption chillers (HEACs) are designed to produce cooling with low-temperature resources. This study proposes a novel configuration that utilizes an ORC for electricity generation, a HEAC for cooling production, and a PEM electrolysis system to produce hydrogen. The power section consists of two turbines, one driven by the vapor produced from the geothermal flow expansion, which powers the PEM section, while the other turbine in the ORC is used to drive pumps and electricity production. First, the system is thermoeconomically analyzed for an initial set of inputs. Then, various parameters are analyzed to determine their influences on system performance. The analyses reveal that the system can work with geothermal source temperatures as low as 80 °C, but the exergy and energy (thermal) efficiencies decrease to around 17% under the base settings. Furthermore, the system is capable of working with resource temperatures up to 170 °C. Ten parameters are found to affect the system’s efficiency and effectiveness. To optimize the system, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is implemented to find the optimum conditions. The objective functions are exergy efficiency and unit polygeneration cost (UPGC), which can conflict. The optimization shows that the exergy efficiency of the system can reach 48% in the optimal conditions (for a heat source temperature of 112 °C and a mass flow rate of geothermal fluid of 44 kg/s), with a hydrogen production rate of 1.1 kg/h.

In the present study, the integration of electrochemically mediated amine regeneration (EMAR) with amine thermal swing process is investigated as a novel method for CO2 capture, utilizing experimental practical data. The aim is to increase the absorption-desorption temperature difference in order to improve the energy efficiency of the capture process and hamper the amine degradation issue at high desorption temperatures. A comprehensive experimental procedure is presented, and an experimental process setup is designed and constructed. As the main novelty of the study a special heating-cooling subsystem is incorporated with the base EMAR process in order to devise a combined electrochemical-thermal system. The performance of the system is evaluated at sequential incremental desorption temperatures while the absorption temperature is kept constant. Relevant data, including the desorbed CO2 flow, absorbed CO2 flow, stream points temperature, and cell voltage are collected. Based on the data collected, two performance parameters are calculated, including normalized carbon separation work, and CO2 desorption density. Based on these performance parameters the system's capability is assessed, and the optimal desorption temperature is ultimately selected. The presented electrochemical-thermal CO2 separation system, operating with a chloride salt system, demonstrates its best energetics performance at a desorption temperature of 44 °C, resulting in a normalized capture work of 95.2 kJ/molCO2. Under these optimal conditions, the cell's average voltage is measured to be 0.37 V, and the CO2 desorption density is determined to be 0.71 l.min−1.m−2.

The present study explores the prospects of operational stability of dual fuel operation comprehensively, considering that; methanol and diesel are of two different kinds which exhibit different combustion processes. To this effect, investigating the stability of engine operation under such condition becomes important. In this investigation, the harshness of the operation and the non-repeatability of the combustion cycles are examined, which have been identified as the major stability indicator in many studies. Such stability indices are characterized in this study through a comprehensive set of parameters, including of maximum pressure rise rate (ROPRmax) and coefficient of variation of indicated mean effective pressure (COVIMEP); and of peak pressure (COVPP) and crank angle of 50% mass fraction burn (COVCA50). The experimental investigation is carried out under a split injection strategy by varying injection timings as well as injection mass percentages at predefined methanol injection durations. It is shown that the partially premixed mode under the split injection strategy exhibits significant potential in reducing the harshness of operation indicated by lower peak pressure rise and increasing the repeatability of the combustion cycles implied by the substantially lower scores of the considered parameters for mapping stability.

Control of a bioprocess is a challenging task mainly due to the nonlinearity of the process, the complex nature of microorganisms, and variations in critical parameters such as temperature, pH, and agitator speed. Generally, the optimum values chosen for critical parameters during Escherichia coli (E.coli) K-12fed-batch fermentation are37 ᵒC for temperature, 7 for pH, and 35 % for Dissolved Oxygen (DO). The objective of this research is to enhance biomass concentration while minimizing energy consumption. To achieve this, an Event-Triggered Control (ETC) scheme based on feedback-feed forward control is proposed. The ETC system dynamically adjusts the substrate feed rate in response to variations in critical parameters. We compare the performance of classical Proportional Integral (PI) controllers and advanced Model Predictive Control (MPC) controllers in terms of bioprocess yield. Initially, the data are collected from a laboratory-scaled 3L bioreactor setup under fed-batch operating conditions, and data-driven models are developed using system identification techniques. Then, classical Proportional Integral (PI) and advanced Model Predictive Control (MPC) based feedback controllers are developed for controlling the yield of bioprocess by manipulating substrate flow rate, and their performances are compared. PI and MPC-based Event Triggered Feed Forward Controllers are designed to increase the yield and to suppress the effect of known disturbances due to critical parameters. Whenever there is a variation in the value of a critical parameter, it is considered an event, and ETC initiates a control action by manipulating the substrate feed rate. PI and MPC-based ETC controllers are developed in simulation, and their closed-loop performances are compared. It is observed that the Integral Square Error (ISE) is notably minimized to 4.668 for MPC with disturbance and 4.742 for MPC with Feed Forward Control. Similarly, the Integral Absolute Error (IAE) reduces to 2.453 for MPC with disturbance and 0.8124 for MPC with Feed Forward Control. The simulation results reveal that the MPC-based ETC control scheme enhances the biomass yield by 7 %, and this result is verified experimentally. This system dynamically adjusts the substrate feed rate in response to variations in critical parameters, which is a novel approach in the field of bioprocess control. Also, the proposed control schemes help reduce the frequency of communication between controller and actuator, which reduces power consumption.

Gas turbine power plants have important roles in the global power generation market. This paper, for the first time, thermodynamically examines the impact of steam injection for a combined cycle, including a gas turbine cycle with a two-stage turbine and carbon dioxide recompression. The combined cycle is compared with the simple case without steam injection. Steam injection’s impact was observed on important parameters such as energy efficiency, exergy efficiency, and output power. It is revealed that the steam injection reduced exergy destruction in components compared to the simple case. The efficiencies for both cases were obtained. The energy and exergy efficiencies, respectively, were found to be 30.4% and 29.4% for the simple case, and 35.3% and 34.1% for the case with steam injection. Also, incorporating steam injection reduced the emissions of carbon dioxide.

In recent years, the critical stage of air pollution and government stringent emission norms like Bharat Standard VI in 2020 in India and Euro VI in European countries, along with the promotion of electric vehicles, has made the future of diesel vehicles unpredictable. The present work correlates and tries to overcome the emission issue by improving fuel properties using a novel multi-additive fuel blend which can control engine emission, mostly NOx, without compromising efficiency and operating fuel economy. Using experimental and literature studies, three additives were identified for creating a novel multi-additive fuel blend, viz. dimethyl carbonate, 2-ethylhexyl nitrate and ethyl acetate. Using the Taguchi Design of Experiment method, sixteen test samples having different combinations of these additive were identified for experimental trials to create sufficient and suitable test data for the optimization process. Technique for Order of Preference by Similarity to Ideal Solution is a Multi Criteria Decision Making optimization process, is performed to identify the optimized multi-additive fuel blend coded as D8EH6E4. Blending the optimized multi-additive sample D8EH6E4 with diesel fuel reduced NOx formation by an average of 19 % while causing a substantial drop in smoke at higher load conditions without adversely affecting engine performance and fuel economy.

Abstract Water scarcity threatens human life and it is likely to be a main concern in the next century. In this work, a novel multigeneration system (MGS) is introduced and assessed with energy, exergy, and economic analyses. This MGS includes a gas cycle, multieffect distillation, an absorption refrigeration cycle, a heat recovery steam generator, and electrodialysis. Electrodialysis is integrated into this configuration to produce sodium hydroxide and hydrogen chloride from brine to prevent its release to the environment with harmful impacts. The other products are electricity, cooling, and demineralized water. For the evaluation of the proposed system, one computer code is provided in engineering equation solver software. For physical properties calculation, the library of this software is used. The MGS produces 614.7 GWh of electrical energy, 87.44 GWh of cooling, 12.47 million m3 of demineralized water, and 0.092 and 0.084 billion kg of sodium hydroxide and hydrogen chloride over a year. Energy and exergy evaluations demonstrate that the MGS energy and exergy efficiencies are 31.3% and 18.7%, respectively. The highest and lowest value of exergy destruction rate is associated with the combustion chamber and pump, respectively. The economic evaluation indicates that the net present value of this proposed system is 3.8 billion US$, while the internal rate of return and payback period, respectively, are 0.49 and 2.1 years.

This paper investigates the total environmental impacts of a thermal caisson (TC) system by implementing a life cycle assessment methodology. The total environmental impacts consider the comprehensive effect on the environment across two life cycle stages: manufacturing and operation. A comparison between the TC results and two different HVAC systems, including air-conditioning/furnace and conventional ground-source heat pump (GSHP) systems, was made by adopting the ReCiPe 2016 methodology. This study reveals that the operation phase is the predominant contributor to environmental impacts across systems, mainly due to its extended duration. Specifically, the operational impacts of GSHPs are substantial, accounting for approximately 87% of total environmental impacts. A TC GSHP system demonstrates a notable environmental advantage, achieving a 79% reduction in total environmental impact when compared to traditional AC/furnace systems. This represents a 21% improvement over conventional GSHP systems. Despite this substantial reduction in total environmental impact, the TC GSHP system shows an almost 5% increase in the resource availability damage category relative to the conventional GSHP, which is attributed to its higher material consumption. These results highlight the TC GSHP system’s superior efficiency in reducing environmental impacts and its potential as a more sustainable alternative in residential heating and cooling applications.

Thermal management of proton exchange membrane (PEM) fuel cells in hydrogen electric and hybrid electric vehicles is of great importance since most of heat generated inside the cells is absorbed by the structure of the fuel cells. Understanding the thermal behavior of PEM fuel cells helps in the design of effective cooling systems to dissipate the heat in the fuel cell and maintain the cell's temperature within the optimum operating range (i.e., 65 °C-75 °C). For the first time, we developed a methodology that combines thermal-electrochemical modeling of PEM fuel cell with empirical heat transfer correlations to reveal the temperature distribution through the structural layers of the PEM fuel cells. In addition, various cooling mediums (including air, hydrogen and water) flowing through the bipolar plate cooling channels are compared in terms of their cooling effects and the uniformity of the temperature distribution in the fuel cells at various flow conditions (i.e., different temperatures and coolant velocities). It is found that, although increasing the coolant flow velocity through the cooling channels enhances heat transfer between the fuel cell surface area and the coolant and reduces the average temperature of the PEM fuel cell, it results in lower temperature uniformity through the structure of the cells compared to lower coolant flow velocities. At a coolant temperature of 35 °C, the maximum temperature of the PEM fuel cell is 88 °C, 79 °C and 56 °C for air, hydrogen and water cooling mediums, respectively. In addition, at a coolant flow velocity of 0.02 m/s, the use of water in the cooling channels results in a temperature difference between the membrane with the highest temperature and the outer surface of the cell with the lowest temperature of 9 °C, while this temperature difference is about 6.5 °C when hydrogen is used as the coolant.

An experimental thermal survey of a turbocharger was performed in an engine test cell using IR thermography. The emissivity coefficients of housings were specified using a furnace and camera. It was shown that the emissivity of the turbine, compressor, and bearing housings are 0.92, 0.65, and 0.74, respectively. In addition, thermocouples were mounted on the housing to validate the temperature of the thermal camera while running in an engine test cell. To compare the data of the thermocouple with data from the thermal camera, an image was taken from the sensor’s location on the housing. The experimental results show that the temperature prediction of the thermal camera has less than 1 percent error. Steady-state tests at various working points and unsteady tests including warm-up and cool-down were performed. The measurements indicate that the turbine casing’s maximum temperature is 839 °C. Furthermore, a thermal image of the bearing housing shows that the area’s average temperature, which is close to the turbine housing, is 7 °C lower than the area close to the compressor housing. The temperature of the bearing housing near the turbine side should be higher; however, the effect of the water passing through the bearing housing decreases the temperature.

Abstract High‐energy demand with rapid industrialization and mechanization combined with environmental pollution due to the burning of fossil fuels has driven a shift toward renewable energy. Biogas derived from biomass is a potential renewable energy source that can be used in different sectors such as transportation sector, electricity generation, heat production, combined heat and power (CHP) systems, and fuel cells. Moreover, the upgraded biogas can be applied as transportation fuel via an internal combustion chamber (for internal combustion engine (ICE) vehicles), and electricity station (for electric vehicles). In the present work, a conceptual review of biogas‐based electrical power production systems is presented. It is clear that the conventional types of biomass contain a high amount of pollutants and unwanted constituents, which lower the lower heating value (LHV) of biogas fuel. Moreover, the energy and exergy efficiencies of biogas applications are influenced by these components. Consequently, several biogas‐upgrading technologies have been elaborated to increase the LHV of biogas fuel by removing biogas pollutants. So, the energy and exergy analyses of biogas‐driven plants are discussed in this regard. Also, the economic analysis of biogas‐fueled systems is measured through the connection between biogas production, purchased electrical power, and selling of an additional amount of biogas. Biogas represents an important source of renewable energy as shown before, and it helps in waste management and W‐to‐E (waste to energy) conversion, which allows utilizing huge amounts of wastes instead of disposal or landfill procedures. However, handling of biogas from production to utilization has an impact on the environment. Therefore, the assessment of the environmental impacts of biogas plants is presented. In addition, a combination of the biogas energy with other sources, especially renewable energy sources (eg, solar‐biogas, geothermal‐biogas, wind‐biogas, CHP, CCHP, and concentrated photovoltaic‐biogas), and reusing waste energy for other tasks (eg, employing the waste heat from a gas turbine) are examined.

Abstract Energy, exergy, exergoenvironmental, and exergoeconomic analyses of a natural gas boosting station are presented using a real‐gas model and actual operational data. The effect of varies performance parameters on the thermodynamic efficiencies, specific fuel consumption (SFC), gas‐phase emissions, and cost rates are assessed. The results show that, for the actual operational conditions of the gas boosting station, the exergy efficiencies are 76.1% and 73.9% in the hot and cold seasons, respectively. Moreover, the energy analysis at partial load reveals that the SFC varies from 0.285 kg/kWh to 0.302 kg/kWh, respectively, in maximum and minimum ambient temperatures. The exergoeconomic analysis along with the exergoenvironmental analysis shows that the total cost rate of gas boosting stations in hot and cold ambient conditions is 7390 US$/h and 8070 US$/h, respectively, with more than 60% related to the environmental impact. In this system, the highest exergoeconomic factor is attributed to the centrifugal gas compressor at 40.9%‐44.2% and the lowest to the air cooler at 0.030%‐0.036%, depending on the ambient temperature, which specifies the balance between capital cost and the cost of exergy destruction. The cost rate of the exergy destruction is more pronounced in the combustion chamber, and the overall cost rate of the exergy destruction can be improved significantly by increasing turbine inlet temperature which needs additional investment cost for the system.

The optimal equipment arrangement for a system for cogeneration of thermal and electrical energy for a total site is determined with exergoeconomic analysis. A steam power plant can operate concurrently in a dual-use mode producing steam and electricity. It is important to know the potential for cogeneration before designing and optimizing a central utility system in order to establish on site fuel demand targets. In the current study, two case studies with different backpressure steam turbines arrangement are considered and, if extra power generation is needed, designs with a system of condensing and gas turbines are examined. The minimum exergy destruction rate, maximum exergy efficiency, minimum total capital cost rate and minimum exergy destruction cost rate for these arrangements are investigated with exergoeconomic analysis. Finally, selected backpressure steam turbines arrangement in conjunction with the gas turbine system are introduced for finding the optimum arrangement of the cogeneration system in the total site with an exergoeconomic approach.

Abstract Transportation sector is one of the core parts of modern civilization. Proper utilization of energy and exergy in this sector is necessary to ensure energy loss and environmental sustainability. Increasing exergy efficiency will reduce carbon emissions from this sector. Since 1970, Reistad estimates have been widely used to determine the energy and exergy efficiencies of this sector. However, the modern transport sector has undergone significant changes in recent decades. Hence, it is necessary to apply new Reistad estimates in determining the energy and exergy efficiencies. This is the first study to apply updated Reistad estimates to explore the energy and exergy efficiencies in the transportation sector of Bangladesh based on the data from 2000 to 2017. The overall exergy efficiency is significantly lower than the energy efficiencies as it ranges from 27.7% to 30.0%. Efficiencies are lower as the maximum portion of input exergy is lost to the environment. The road subsector needs major improvements as it is responsible for major amount of exergy loss. A comparison is made between conventional and updated estimates which highlights that the updated estimates provide more accurate results. Thus, it is recommended to apply updated Reistad estimates in determining the energy and exergy efficiencies of the transport sector.

ABSTRACT: The current study aims to validate and apply an instrument to assess the relationship between institutional support, technological literacy, and self-efficacy on the intention to participate in the Facebook Metaverse using social cognitive theory. We performed a cross-sectional, analytical study of 410 citizens in Peru to assess the influence of institutional support, technological literacy, and self-efficacy on the intention to participate in the Facebook Metaverse during the COVID-19 pandemic. The research model was validated using partial least square structural equation modeling (PLS-SEM) to establish the influence of variables on the model. Institutional support and technological literacy were found to influence the self-efficacy of participating in the metaverse positively by correlations of 0.573 and 0.257, respectively. Self-efficacy of participating positively influenced the intention to participate in the Facebook Metaverse by 0.808. The model explained 65.4% of the intention to participate in the Facebook Metaverse. Bootstrapping demonstrated that the path coefficients of the research model were statistically significant. The research outcomes may help firms to develop planning and investment in the metaverse, as well as understanding the factors that influence a higher intention to participate in the Facebook Metaverse.

Abstract The yearly thermo‐economic performance is dynamically investigated for three solar heating and cooling systems: solar heating and absorption cooling (SHAC), solar heating and ejector cooling (SHEC), and heating and solar vapor compression cooling (HSVC). First, the effects of important design parameters on the thermo‐economic performance of the systems to supply the heating and cooling loads of the building are evaluated. The systems are parametrically analyzed with the weather conditions of Tehran, Iran. The results show that the life cycle costs (LCC) of the SHAC and HSVC systems are alike and much lower than those of the SHEC system. The HSVC system exhibits the best performance from exergetic and solar fraction viewpoints. The comparative analysis shows that the energy efficiencies of the SHAC and SHEC systems are higher in colder climatic conditions. However, the collector efficiency of the HSVC system declines in colder climates, mainly due to the lower solar intensities relative to in hotter climates. Further, the solar fraction of the SHAC system is higher than the SHEC technology under all climatic conditions. Moreover, higher values of solar fractions are obtained under colder weather conditions for the SHEC and HSVC systems. The best economic performance is observed for the SHAC and HSVC technologies, having significantly lower LCCs than the SHEC system. These lower LCCs under colder climatic conditions are due to the lower cost of supplying the heating load compared to the cooling load. Furthermore, all systems exhibit enhanced exergetic performance in colder weather conditions. The yearly thermo‐economic performance is dynamically investigated for three solar heating and cooling systems: SHAC, SHEC, and HSVC. In addition, the effects of important design parameters on the thermo‐economic performance of the systems to supply the heating and cooling loads of the building are evaluated.

Ensuring sustainability in electrical power generation is a major concern in the modern world. Reducing energy depletion from power generation can reduce emissions and contribute to sustainability. Exergy analysis can be used to assess and optimize energy systems and thus can help achieve sustainability. In this analysis, energy and exergy utilization of Bangladesh’s utility sector is investigated based on data from 2007 to 2016. The overall energy efficiencies vary from 34.9% to 36.3% while the exergy efficiencies vary from 35.0% to 39.2% within this period. Thermal power plants are seen to have greater exergetic improvement potential than hydro power plants. To correlate between exergy and environmental sustainability, this study applies several exergetic parameters as sustainability indicators. It is found that the depletion number varies between 0.61 and 0.65 while the exergy sustainability index varies between 1.54 and 1.64. The relative irreversibility and lack of productivity are greater for gas operated power plants than other thermal power plants. The largest relative irreversibility is 0.90 while the largest lack of productivity is 1.72. The waste exergy ratio varies from 0.48 to 0.59 while the environmental effect factor varies from 1.35 to 1.68. Renewable power generation is found to have a higher sustainability than fossil fuel power generation. It is believed that current analysis can serve as a benchmark to help attain power generation sustainability.

An exergoeconomic analysis is reported of a geothermal-based combined system for electricity and freshwater in which a geothermal steam turbine is integrated with multi-effect desalination and reverse osmosis systems. The article includes an exergy analysis, an economic assessment and an exergoeconomic (i.e., exergy-based economic) evaluation. The specific exergy costing method is used for the analysis of the system to determine the effects of various design criteria on the cost rates and then to incorporate feasible improvements for enhanced cost effectiveness. The results of the exergoeconomic analysis can assist in the design, optimization and improvement of geothermal-based electricity-freshwater production combined systems. It is found that the exergoeconomic factors for the reverse osmosis, multi-effect desalination and steam turbine are high, all exceeding 85%. Thus, reducing the investment costs for these components is merited. This can be done by any of the following measures, among others: reducing heat transfer area in the multi-effect desalination system, using less expensive pumps and membranes in reverse osmosis, and lowering the expansion ratio, turbine inlet temperature and isentropic efficiency for the steam turbine.

Investigating the constructions of borehole heat exchangers with high efficiency (unit heat transfer between the heat carrier and ground) is important. One of the means to improve efficiency is the use of the most efficient construction of the borehole heat exchanger. The paper describes research on borehole heat exchangers’ thermal efficiency, which is mainly characterized by parameters obtained from a thermal response test: effective thermal conductivity and borehole thermal resistivity. The borehole heat exchangers of the Laboratory of Geoenergetics in Poland were studied. Based on thermal response test interpretation and empirical equations, one of which is proprietary, the heat transfer is calculated independent of the duration of the thermal response test. Other conditions for using borehole heat exchangers in downtowns are discussed. The research aims to determine the best borehole heat exchanger design from five basic possibilities studied. A lack of unequivocal statements regarding this matter in the literature was observed. The influence of the interpretation method on the research results is determined. A single U-tube system filled with gravel is shown to be the most advantageous design by a very small margin. The applied interpretation methods, however, confirm the hitherto ambiguity in the selection of the best construction. The maximum heat carrier temperature at the end of thermal response tests was 32 °C for a geological profile mostly made up of clay (low thermal conductivity) and 23 °C for Carpathian flysch (sandstones and shales, with a higher value of conductivity).

Energy, exergy, and exergoeconomic evaluations of various geothermal configurations are reported. The main operational and economic parameters of the cycles are evaluated and compared. Multi-objective optimization of the cycles is conducted using the artificial bee colony algorithm. A sensitivity assessment is carried out on the effect of production well temperature variation on system performance from energy and economic perspectives. The results show that the flash-binary cycle has the highest thermal and exergy efficiencies, at 15.6% and 64.3%, respectively. The highest generated power cost and pay-back period are attributable to the simple organic Rankine cycle (ORC). Raising the well-temperature can increase the exergy destruction rate in all configurations. However, the electricity cost and pay-back period decrease. Based on the results, in all cases, the exergoenvironmental impact improvement factor decreases, and the temperature rises. The exergy destruction ratio and efficiency of all components for each configuration are calculated and compared. It is found that, at the optimum state, the exergy efficiencies of the simple organic Rankine cycle, single flash, double flash, and flash-binary cycles respectively are 14.7%, 14.4%, 12.6%, and 14.1% higher than their relevant base cases, while the pay-back periods are 10.6%, 1.5% 1.4%, and 0.6% lower than the base cases.

The circular economy can contribute to the eco-efficient use of resources. Firms can obtain relevant benefits if they implement a circular economy. In Peru, the circular economy would create benefits, but it is not fully clear what factors explain the acceptance of firms of implementing a circular economy. Following the theory of planned behavior, the current research assesses the influence of attitudes, subjective norms, perceived behavioral norms, intentions, and pressures on behaviors towards the circular economy. A total of 71 medium-size firms based in Peru participated in an online survey. Six questions were focused on general information, and forty-seven questions evaluated the circular economy behavior of firms. A partial least square structural equation modeling technical analysis was used. It was found that attitudes (0.144), subjective norms (0.133), and perceived behavioral control (0.578) had a positive influence on intentions; also, perceived behavioral control (0.461) had a positive influence on behaviors towards the circular economy. Finally, pressures had a positive influence (0.162) on behaviors towards the circular economy. The model explained 64.3% of the behaviors towards the circular economy. The outcomes of the bootstrapping test were used to evaluate if the path coefficients are significant. This study showed that attitudes, subjective norms, perceived behavioral norms, intentions, and pressures explained circular economy behaviors. This information can help firms develop strategies to move forward a circular economy and provide governments information about the current situation of circular economy implementation to generate new norms and strategies for more implementation of circular economy measures in enterprises. The novelty is based on using the PLS-SEM technique.

Humanity and societies today face important challenges related to sustainability and these are expected to become more significant in the future. Making societies and their development more sustainable requires the consideration of economic, social, environmental and other factors. Sustainability assessment tools are needed to evaluate how is the sustainability of a process or system, and how that is affected when a change is made. To account for all relevant factors, a comprehensive set of indicators is required, including both quantitative indicators which are measurable and practical and qualitative indicators where necessary. In this article, sustainability concepts and definitions are reviewed and the historical context for sustainability is briefly described. Then sustainability is discussed, focusing on its economic, environmental and social dimensions, and the related concept of sustainable development is examined. Issues related to sustainability are discussed throughout. Finally, assessment measures for sustainability are examined, and several applications are presented.

The relation between rotation speed, air pressure and the velocity of air-rotary drilling using the down the hole method is determined in an empirical manner. For the study, velocity measurements are obtained for combinations of the aforementioned parameters during fieldwork for the installation of borehole heat exchangers near Lublin, Poland. The tests consider three drill bit diameters—110, 127 and 140 mm; three rotational speeds—20, 40 and 60 1/min; and three air pressures—16, 20 and 24 bar. The borehole heat exchangers need 100 m deep wells. The lithology consists mainly of loess and clays to 24 m, sand and carbonate rocks to 36 m, and marls and limestone to 100 m. It is found that the highest drilling velocity is achieved when the greatest pressure is applied, while the lowest drilling velocity is connected to the lowest pressure. However, the relation between rotation speed and drilling velocity is more complex, as drilling velocity seems to be more affected by depth. Therefore, lithology can be a major factor. The results may find direct use in drilling, and provide a basis for further studies on the optimization of drilling technology.

Electric vehicles (EVs) are recognized as promising options, not only for the decarbonization of urban areas and greening of the transportation sector, but also for increasing power system flexibility through demand-side management. Large-scale uncoordinated charging of EVs can impose negative impacts on the existing power system infrastructure regarding stability and security of power system operation. One solution to the severe grid overload issues derived from high penetration of EVs is to integrate local renewable power generation units as distributed generation units to the power system or to the charging infrastructure. To reduce the uncertainties associated with renewable power generation and load as well as to improve the process of tracking Pareto front in each time sequence, a predictive double-layer optimal power flow based on support vector regression and one-step prediction is presented in this study. The results demonstrate that, through the proposed control approach, the rate of battery degradation is reduced by lowering the number of cycles in which EVs contribute to the services that can be offered to the grid via EVs. Moreover, vehicle to grid services are found to be profitable for electricity providers but not for plug-in electric vehicle owners, with the existing battery technology and its normal degradation.

Research on borehole heat exchangers is described on the development of a method for the determination, based on thermal response tests, of the effective thermal conductivity and the thermal resistivity for borehole heat exchangers. This advance is important, because underground thermal energy storage increasingly consists of systems with a large number of borehole heat exchangers, and their effective thermal conductivities and thermal resistivities are significant parameters in the performance of the system (whether it contains a single borehole or a field of boreholes). Borehole thermal energy storages provide a particularly beneficial method for using ground energy as a clean thermal energy supply. This benefit is especially relevant in cities with significant smog in winter. Here, the authors describe, in detail, the development of a formula that is a basis for the thermal response test that is derived from Fourier’s Law, utilizing a new way of describing the basic parameters of the thermal response test, i.e., the effective thermal conductivity and the thermal resistivity. The new method is based on the resistivity equation, for which a solution giving a linear regression with zero directional coefficient is found. Experimental tests were performed and analyzed in support of the theory, with an emphasis on the interpretation differences that stem from the scope of the test.

The use of exergy to correlate energy-utilization efficiencies and energy research investments is described. Specifically, energy and exergy losses are compared with energy research and development expenditures, demonstrating that the latter correlates with energy losses, even though it would be more sensible to allocate energy research and development funding in line with exergy losses, as they represent the actual deviation of efficiency from the ideal. The methodology is outlined and illustrated with two case studies. The case studies consider the province of Ontario, Canada and the United States. The investigation utilizes data on the energy utilization in a country or region, including flows of energy and exergy through the main sectors of the economy. The results are expected to be of use to government and public authorities that administer research and development funding and resources and should help improve the effectiveness of such investments.

Parametric studies of the effects of slip irreversibility in concentrating solar power (CSP)-powered bio-digester assemblies are investigated. Complexities regarding the identification of the appropriate electro-kinetic phenomena for certain electrolyte phases are reviewed. The application of exergy analysis to the design of energy conversion devices, like solar thermal collectors, for the required heat of formation in a downdraft waste food bio-digester, is discussed. Thermal management in the silicon-based substrate of the energy system is analyzed. The rectangular-shaped micro-channels are simulated with a finite-volume, staggered coupling of the pressure-velocity fields. Entropy generation transport within the energy system is determined and coupled with the solution procedure. Consequently, the effects of channel size perturbation, Reynolds number, and pressure ratios on the thermal performance and exergy destruction are presented. A comparative analysis of the axial heat conduction for thermal management in energy conversion devices is proposed.

Theoretically, the concepts of energy, entropy, exergy and embodied energy are founded in the fields of thermodynamics and physics. Yet, over decades these concepts have been applied in numerous fields of science and engineering, playing a key role in the analysis of processes, systems and devices in which energy transfers and energy transformations occur. The research reported here aims to demonstrate, in terms of sustainability, the usefulness of the embodied energy and exergy concepts for analyzing electric devices which convert energy, particularly the electromagnet. This study relies on a dualist view, incorporating technical and environmental dimensions. The information provided by energy assessments is shown to be less useful than that provided by exergy and prone to be misleading. The electromagnet force and torque (representing the driving force of output exergy), accepted as both environmental and technical quantities, are expressed as a function of the electric current and the magnetic field, supporting the view of the necessity of discerning interrelations between science and the environment. This research suggests that a useful step in assessing the viability of electric devices in concert with ecological systems might be to view the magnetic flux density B and the electric current intensity I as environmental parameters. In line with this idea the study encompasses an overview of potential human health risks and effects of extremely low frequency electromagnetic fields (ELF EMFs) caused by the operation of electric systems. It is concluded that exergy has a significant role to play in evaluating and increasing the efficiencies of electrical technologies and systems. This article also aims to demonstrate the need for joint efforts by researchers in electric and environmental engineering, and in medicine and health fields, for enhancing knowledge of the impacts of environmental ELF EMFs on humans and other life forms.

The benefits are demonstrated of using exergy to understand the efficiencies of electrical power technologies and to assist improvements. Although exergy applications in power systems and electrical technology are uncommon, exergy nevertheless identifies clearly potential reductions in thermodynamic losses and efficiency improvements. Various devices are considered, ranging from simple electrical devices to generation systems for electrical power and for multiple products including electricity, and on to electrically driven. The insights provided by exergy are shown to be more useful than those provided by energy, which are sometimes misleading. Exergy is concluded to have a significant role in assessing and improving the efficiencies of electrical power technologies and systems, and provides a useful tool for engineers and scientists as well as decision and policy makers.

The trajectory and deposition efficiency of micron-sized (1–5 µm) particles, inhaled into the pulmonary system, are accurately determined with the aid of a newly developed model and modified simulation techniques. This alveolar model, which has a simple but physiologically appropriate geometry, and the utilized fluid structure interaction (FSI) methods permit the precise simulation of tissue wall deformation and particle fluid interactions. The relation between tissue movement and airflow in the alveolated duct is solved by a two-way fluid structure interaction simulation technique, using ANSYS Workbench (Release 16.0, ANSYS INC., Pittsburgh, PA, USA, 2015). The dynamic transport of particles and their deposition are investigated as a function of aerodynamic particle size, tissue visco-elasticity, tidal breathing period, gravity orientation and particle–fluid interactions. It is found that the fluid flows and streamlines differ between the present flexible model and rigid models, and the two-way coupling particle trajectories vary relative to one-way particle coupling. In addition, the results indicate that modelling the two-way coupling particle system is important because the two-way discrete phase method (DPM) approach despite its complexity provides more extensive particle interactions and is more reliable than transport results from the one-way DPM approach. The substantial difference between the results of the two approaches is likely due to particle–fluid interactions, which re-suspend the sediment particles in the airway stream and hence pass from the current generation.

The computational thermodynamic analysis of a samarium oxide-based two-step solar thermochemical water splitting cycle is reported. The analysis is performed using HSC chemistry software and databases. The first (solar-based) step drives the thermal reduction of Sm2O3 into Sm and O2. The second (non-solar) step corresponds to the production of H2 via a water splitting reaction and the oxidation of Sm to Sm2O3. The equilibrium thermodynamic compositions related to the thermal reduction and water splitting steps are determined. The effect of oxygen partial pressure in the inert flushing gas on the thermal reduction temperature (TH) is examined. An analysis based on the second law of thermodynamics is performed to determine the cycle efficiency (ηcycle) and solar-to-fuel energy conversion efficiency (ηsolar−to−fuel) attainable with and without heat recuperation. The results indicate that ηcycle and ηsolar−to−fuel both increase with decreasing TH, due to the reduction in oxygen partial pressure in the inert flushing gas. Furthermore, the recuperation of heat for the operation of the cycle significantly improves the solar reactor efficiency. For instance, in the case where TH = 2280 K, ηcycle = 24.4% and ηsolar−to−fuel = 29.5% (without heat recuperation), while ηcycle = 31.3% and ηsolar−to−fuel = 37.8% (with 40% heat recuperation).