Energy Efficiency Analysis Research Articles

Methodology for Energy Efficiency Analysis and Optimization of Ship Systems using Exergy Modeling

Methodology for Energy Efficiency Analysis and Optimization of Ship Systems using Exergy Modeling

Study Of Energy Management And Efficiency In Industrial Processes: Analysis Of Implementation And Its Impact On Productivity

This study focuses on the implementation and analysis of energy management and efficiency in the context of industrial processes to enhance productivity. Drawing upon literature review on the fundamental concepts of energy management and best practices in industries, this research identifies strategies and methods that can be applied to optimize energy use in manufacturing environments. The research methodology involves gathering data from various sources to evaluate the practical implementation of energy management strategies in manufacturing industries, including pre- and post implementation data analysis. The findings provide deep insights into the effectiveness of specific measures in reducing energy consumption, improving operational efficiency, and their overall impact on productivity. The study also highlights challenges that may arise in implementing energy management strategies, such as initial costs, staff training needs, and technology integration. However, the long-term benefits of efficient energy management include reduced operational costs and environmental sustainability. By combining technical and managerial approaches, this research provides a foundation for better decision-making in adopting sustainable practices in the industrial sector.

Energy efficiency and thermal stress analysis of hexahedron and tetrahedron nanoparticles in annular fin with ternary nanofluid

Energy efficiency and thermal stress analysis of hexahedron and tetrahedron nanoparticles in annular fin with ternary nanofluid

Year around study of tubular solar still with green almondshells biowaste as energy storage material: energy, economic, and environmental analysis.

Solar-based desalination is one of the prominent contributors to overcoming the water scarcity problems in desert areas and a major alternative to fossil fuel-based desalination methods. The present study focuses on utilizing green almond shells (green almond shells) as energy storage materials in tubular solar still (TSS) to enhance water productivity, energy efficiency, and economic and environmental analyses. Further, this study discusses the yearly water output, annual energy efficiency, and economic and environmental analyses. Two different TSS were utilized which consists of conventional TSS (CTSS) without any storage materials and modified TSS with the inclusion of green almond shells (MTSS) in the climatic conditions of Chennai, India. The yearly distilled water output from the CTSS and MTSS was evaluated as 512 and 691.2kg/m2, respectively. The yearly distilled water output from the MTSS is 26% higher when compared to the CTSS. Furthermore, the maximum monthly energy efficiency of the CTSS and MTSS was 14.4 and 19.44%, respectively. The annual energy efficiency of the CTSS and MTSS is 12.6 and 17.02%, respectively. The economic analysis of the system is also carried out, and the findings show that better economic feasibility is achieved in MTSS considering the INR 5 (Indian Rupees) cost of water. The payback period for MTSS was 12months, while for CTSS it is calculated to be 20months. Furthermore, CO2 emission and mitigation have also been evaluated, and the results indicate that the utilization of porous material has increased the emission for MTSS, while CO2 mitigation has been significantly higher as compared to the CTSS system.

Exploration of environmentally friendly processes for converting CO2 into propanol through direct hydrogenation

This study firstly explores six process configurations for the conversion of CO2 to propanol via direct hydrogenation. The variations in the proposed configurations lie in the technologies used for off-gas treatment (such as pressure swing adsorption, oxyfuel combustion, autothermal reforming, and chemical absorption) and the intensification of separation (including the incorporation of the hydration reaction of ethylene oxide) within the process. Energy efficiency analysis, techno-economic analysis (in minimum required selling price, MRSP), and life cycle assessment (on global warming potential, GWP) were conducted to evaluate all proposed schemes. Overall, this study suggests that enhancing the selectivity towards propanol and implementing a suitable off-gas treatment strategy are crucial for this process. Based on the findings, we recommend Scheme 4, which involves auto-thermal reforming for off-gas treatment, as the optimal configuration. It leads to an energy efficiency of 45.33 %. Despite the higher MRSP (3.12 USD/kg when using grey H2, 7.45 USD/kg when using green H2, commercial process: 1.4 to 1.6 USD/kg), it significantly reduces GWP (3.19 kg-CO2-eq/kg when using grey H2, 1.59 kg-CO2-eq/kg when using green H2) created from the conventional process (6.77 kg-CO2-eq/kg). Given appropriate economic incentives, the proposed process could serve as a more environmentally friendly option for propanol production.

Do bitcoin electricity consumption and carbon footprint exhibit random walk and bubbles? Analysis with policy implications

One of the main current focuses of global economies and decision-makers is the efficiency of energy utilization in cryptocurrency mining and trading, along with the reduction of associated carbon emissions. Understanding the pattern of Bitcoin's energy consumption and its bubble frequency can greatly enhance policy analysis and decision-making for energy efficiency and carbon emission reduction. This research aims to assess the validity of the random walk hypothesis for Bitcoin's electricity consumption and carbon footprint. We employed both traditional methods (ADF and KPSS) and recently proposed unit root techniques that account for structural breaks and non-linearity in the data series. Our analysis covers daily data from July 2010 to December 2021. The empirical results revealed that traditional unit root techniques did not confirm the stationarity of both bitcoin's electricity consumption and carbon footprint. However, novel structural break (SB) and linearity tests conducted enabled us to discover five SB episodes between 2012 and 2020 and non-linearity of the variables, which informed our application of the newly developed non-linear unit root tests with structural breaks. With the new methods, the results indicated stationarity after accommodating the SB and non-linearity. Furthermore, based on Phillips and Shi (2019)'s test, we identified certain bubble episodes in the bitcoin energy and carbon variables between 2013 and 2021. The major drivers of the bubbles in bitcoin energy consumption and carbon footprint are variables relating to the bitcoin and financial markets activities and risks, including the global economic and political risks. The study's conclusion based on the above findings informs several policy implications drawn for energy and environmental management including the encouragement of green investments in cryptocurrency mining and trading.

Spatial conditional convergence analysis of total factor energy efficiency based on industry transfer and technology diffusion

Measuring energy efficiency is important to achieve the goal of sustainable economic development. This paper adopts the Malmquist index to measure the trend of regional total factor energy efficiency. This paper analyses the spatial aggregation characteristics of TFEE and the impact mechanism of industrial transfer and technology diffusion on TFEE convergence from a dynamic perspective. The results of the study show that there is a large gap in TFEE between regions in China, with a spatial characteristic of “high in the south and low in the north”. In 2006–2021, the convergence rate of TFEE shows a slowing down trend. Industrial transfer has a negative effect on TFEE. The impact of technology diffusion on TFEE is different in different periods. The impact of researchers, technology market, technology introduction, and import-export on TFEE have significant differences. The convergence rate of the south is higher than that of the north. The impact of industrial transfer and technology diffusion on TFEE in the two parts is different. Policymakers should implement differentiated energy policies based on the characteristics of the industrial structure and technological development of each region. They should actively guide technological innovation, promote industrial diversification, and build a clean and efficient energy system.

Implementation of a waste heat recovery prototype facility based on the Rankine cycle with a twin-screw expander

Considering the energy needs of developing countries, thermal power plant facilities are necessary for power generation. However, usable thermal energy is lost because the necessary technologies to exploit the waste heat from industrial processes have not yet been implemented. In this sense, the present analysis shows the experimental study of a prototype Steam Rankine Cycle energy system. The prototype uses the residual heat of the combustion gases from one of the generators installed in a thermal power plant as a heat source, the maximum temperature of these gases is 320 °C. This prototype is considered the first in the region to perform heat recovery with a power cycle with water as the working fluid. Considering the country’s economic constraints, the prototype was built using a 20 kW twin-screw compressor modified to function as a turbine. This prototype aims to increase the overall performance of the generating unit. For the characterization of this prototype plant, energy and exergetic efficiency analysis was carried out using the experimental data. The application showed that the measured efficiency of the twin-screw expander was low at 18.44 %. In contrast, the maximum expander work was 15.81 kW, the overall cycle efficiency was 3.52 %, and the exergetic efficiency was 5.45 %.

Environmental and energy efficiency of a selected municipal wastewater treatment plant – a case study

Based on the analysis of environmental and energy efficiency in the years 2019–2021 in the selected sewage treatment plant (WWT) located in the southern Poland with mechanical-biological wastewater treatment, it was found that the highest level of pollution reduction of 98% enabled the highest BOD5 concentration to be reduced more than 800 times. The operation of the sewage treatment plant was characterized by variable efficiency of the treatment process, which was demonstrated by significant differences in chemical indicators (BOD5, COD, P, TSS and N). Low average concentration of total nitrogen below 4 mg l−1 occurred with a reduction of pollutants at a level not exceeding 90%. Noticeable energy consumption of 1.58 kWh m−3 related to the increase in the amount of treated sewage, confirmed by a moderate correlation, indicated the need to optimize the treatment process.

Drinking event detection on a sensing wristband using machine learning

Adequate hydration is important for one’s health, but many people do not consume sufficient fluids. By constantly monitoring fluid intake, we gain information that can be extremely useful in dealing with unhealthy drinking habits. This paper deals with the problem of developing a machine learning method for drinking detection, intended for use on an edge device, with a specific focus on power consumption. The proposed approach is based on data from inertial sensors built into a practical, non-invasive wrist-worn device that monitors wrist movement throughout the day and automatically detects drinking events. It ensures low energy consumption by triggering the machine learning only when the probability of drinking is high, as well as by other energy saving measures. To develop and validate our methods, we collected data from 19 participants, which resulted in 135 hours of data, of which 2 hours and 30 minutes correspond to drinking activities. The algorithm was thoroughly assessed through both offline testing and by running the algorithm directly on the wristband in real life. During the offline evaluation, we obtained a precision of 94.5 %, a recall of 84.9 %, and an F1 score of 89.4 %. Testing in real life demonstrated a precision of 74.5 % and a recall of 89.9 %. Additionally, the energy efficiency analysis showed that our proposed technique for triggering the drinking detection method reduced the battery power consumption during the periods of inactivity by a factor of 5.8 compared to continuously monitoring for drinking events.

Towards China's dual-carbon target: Energy efficiency analysis of cities in the Yellow River Basin based on a “geography and high-quality development” heterogeneity framework

The Yellow River Basin (YRB) serves as a critical energy hub in China. Enhancing energy efficiency in cities across the YRB is pivotal for achieving high-quality development and meeting carbon peaking and neutrality targets. This paper proposes a multidimensional technology heterogeneity assessment framework to refine the classification of production technologies. It leverages this framework to develop a data envelopment analysis model for evaluating green total factor energy efficiency (GTFEE) in 78 cities within the YRB from 2006 to 2022. The key findings are as follows: (1) Grouping outcomes from the multidimensional heterogeneity framework significantly differ from existing literature. (2) GTFEE shows notable spatiotemporal variations within the YRB, with a substantial overall increase since 2011. However, cities in the central YRB exhibit lower GTFEE performance. (3) Energy inefficiency in groups 1, 2, and 3 is attributed to developmental inefficiency, management inefficiency, and practical inefficiency, respectively. (4) Evaluation of energy-saving potential reveals an average annual potential of around 8 million tce per city during 2006–2022. The study concludes with strategies for enhancing GTFEE based on dynamic GTFEE decomposition outcomes, supporting policy design for achieving dual-carbon goals through improved energy efficiency in the YRB region.

Energy efficiency analysis of heavy goods vehicles in road transportation: The case of Morocco

Passenger and freight transport are central to the socio-economic development of countries and urban life. Their enormous consumption of fossil fuels is problematic. It is essential to improve the efficiency and sustainability of this industry, especially in road transport. This paper assesses the heavy goods vehicles (trucks), as a specific segment of road transport, in Morocco from an energy standpoint. For this purpose, a methodology called DMAIC (Define, Measure, Analyze, Improve, and Control) was adopted to systematically define problems, measure the current state, analyze data to identify inefficiencies, as well as implement and monitor improvements for sustainable performance in this sector. The findings show that Moroccan trucks have significant sustainability gaps, characterized, mainly, by high fossil fuel consumption resulting in high exhaust emissions. The promotion of alternative powertrains such as hybrid, electric and fuel cell vehicles offer promising opportunities to reduce oil consumption and greenhouse gas emissions. Although these alternative powertrains have the potential to improve operational performance over traditional diesel models in Morocco, several challenges need to be addressed for their widespread uptake.

Characterization of Several Pellets from Agroforestry Residues: A Comparative Analysis of Physical and Energy Efficiency

The use of agroforestry biomass provides several advantages, both from an environmental point of view, in terms of the mitigation of global warming, and in terms of a circular economy for agricultural or agroforestry companies that reuse pruning residues as a source of energy. However, even if the use of energy pellets resulting from the pruning residues of various agroforestry species has excellent potential for the valorization of agricultural by-products, the physicochemical characteristics of these pellets have been scarcely studied by the scientific community. In this context, this study aims to assess the valorization potential of various lignocellulosic material residues produced during agroforestry activities. The objectives of the study include evaluating the chemical and physical characteristics of pellets produced with different mixtures of agroforestry biomass (olive, citrus, black locust, poplar, paulownia, etc.) in order to determine the optimal pellet blend from an energy and physicochemical perspective. The results of this study demonstrate that this comprehensive analysis provides valuable information on the optimization of biomass mixtures for better energy valorization, addressing both compositional and combustion-related challenges. In fact, it is observed that the addition of citrus and olive biomass to the various mixtures increases their energy potential. Furthermore, all of the pellets analyzed are found to possess an adequate and useful durability index (PDI) for their handling during storage and transport operations. This study demonstrates that olive and citrus pruning residues can be used to improve biomasses that have poor suitability in energetic, physical, and chemical terms. Further studies could be useful to understand which specific interaction mechanisms have an influence on emissions in order to optimize mixtures using different biomass sources for sustainable energy production.

Reformer + Membrane separator plant for decarbonized hydrogen production from Biogas/Biomethane: An experimental study combined to energy efficiency and exergy analyses

Nowadays, the world energy production is still based on the exploitation of fossil fuels, mainly oil, coal, and natural gas, responsible for large greenhouse emissions in the environment. According to the measures proposed by the European Green Deal to meet the carbon neutrality by 2050, the decarbonisation of the global energy production processes represents a top priority. Hydrogen represents a carbon-free energy carrier, useful to drive the society toward a decarbonized-economy. The novelty of this work is represented by the experimental generation of clean hydrogen by a two stages plant constituted of a biogas/biomethane steam reformer and a Pd-Ag membrane separator, meanwhile applying on this simple case the methodology of the exergy analysis, identifying the main losses and suggesting improvements. Hence, it deals with the exergy analysis of the whole system with the process intensification operated by the membrane separator adopted instead of using several stages to separate/purify hydrogen − as conventionally done after the reforming stage (two water gas shift reactors, high and low temperature, followed by a pressure swing adsorption stage) − with the objective of recovering decarbonized hydrogen coming from the biogas/biomethane steam reformer, meeting the European targets indicated by the Clean Hydrogen Alliance. This approach allowed to understand the amount of irreversibilities present in such a system as well as how the thermal efficiency may be influenced by a number of parameters, constituting globally a baseline for the scaling up of this process technology from lab to bench/pilot scale. The best results of this work highlight that the utilization of biomethane in the feed stream to generate hydrogen resulted to be a better choice than biogas in terms of thermal efficiency (based on the lower heating value) of the whole system, equal to 73 % at 773 K, while the highest percentage of exergy destruction was concentrated in the condensation stage, with values varying between 76 % and 93 %, depending on the feed stream typology. The two stages system was able to meet the “decarbonized hydrogen production target 2027”, with a hydrogen recovery of 90 % and a purity of 99.9999 %. Last but not least, the overall exergy destroyed efficiency of the overall system in the two analyzed cases was 92 % (biomethane feed stream) and 88 % (biogas feed stream), respectively.

Factor mismatch measurement of resource-based cities: Evidence from all-round optimization total factor productivity decomposition framework

In-depth analysis of the factors affecting the transformation of resource-based cities can provide effective support for the transformation and development of resource-dependent regions. How to comprehensively identify the factors affecting the transformation of resource-based cities is a complex problem. This study starts from the total factor productivity model and focuses on the two core basic factors that affect the transformation process of cities reliant on resources. Economic benefits and energy efficiency, respectively, from the economic benefit analysis framework and energy efficiency analysis framework for reconstruction, the two frameworks are combined with the use of distorted prices of resource elements to solve the problem that the synergistic effect of economic benefits and energy efficiency can not be measured. In order to quantitatively analyze the factors that affect the development efficiency of cities reliant on resources under the single or synergistic effect of the comprehensive framework, this study optimizes the directional distance function from three perspectives: exogenous weight, direction vector endogeneity, and absolute distance transformation relative distance, thus achieving an accurate assessment transformation efficiency of cities reliant on resources. Considering the impact of the new coronavirus epidemic, this study only selected the data of resource-based cities from 2003 to 2018, and found through model calculation that the impact on the transformation of cities reliant on resources: (1) Labor mismatch is mainly achieved by affecting the structure about the production of resource-based enterprises and industrial human resources; (2) Capital mismatch is mainly realized by affecting the production of resource-based enterprises; (3) Energy mismatch is mainly achieved by affecting high energy consumption enterprises and low production technology level enterprises. Further research shows that the main objects of these factors are the four parts of production technology level, energy consumption, total factor productivity and industrial structure. Through these contents, they affect environmental efficiency and deeply affect the transformation process of resource-based cities.

Building Energy Efficiency Analysis and Diagnosis Using Integrated Image Processing and Thermal Imaging Technologies

Building Energy Efficiency Analysis and Diagnosis Using Integrated Image Processing and Thermal Imaging Technologies

DATAWARE AND SOFTWARE OF THE AUTOMATED TECHNOLOGY FOR COMPUTER- INTEGRATED CONTROL OF HEAT PUMP SYSTEMS

The paper has solved a scientific and applied problem as for substantiating requirements to technical and functional characteristics of the automated technologies of computer-integrated control of heat pump systems in the heating and cooling modes owing to its dataware and software developing and testing. Following functional procedures have been taken into consideration during the dataware and software development of the computer-integrated subsystem for heating of buildings: monitoring of ambient air temperature, ground temperature, and operating modes of functional elements of the heat pump system as well as zonal monitoring of indoor air temperature; computer-integrated processing of the monitoring data; automated control of the heat pump as well as modes of zonal thermal medium supply to the building; and analysis of energy efficiency as for implementation of the proposed computer-integrated method to control systems of thermodynamic heating. It has been identified that thermal capacity of a heat pump is rather sensitive to indicators of the total heat losses of a building. If the total heat losses increase from 0.2°С/hour up to 0.5°С/hour then constant value of the thermal capacity increases by 48%. Moreover, thermal capacity of a heat pump is quite sensitive to ambient air temperature dynamics: if temperature variation is 12°С (i.e. 3°С-9 °С) then average increase in thermal capacity is 58 %. Following functional procedures have been involved during the dataware and software development of the computer-integrated subsystem for cooling of buildings: monitoring of ambient air temperature and operating modes of functional elements of the heat pump system; zonal computer-integrated monitoring of indoor air temperature; computer-integrated the monitoring data processing based upon microcontrollers; automated control of the thermal pump operating modes (i.e. heat energy outfeed and release to the main intercooler unit); and analysis of energy efficiency as for implementation of the proposed computer-integrated method to control systems of thermodynamic cooling of buildings. The abovementioned has helped identify that thermal capacity of a heat pump is rather sensitive to indicator of heat exchange with surrounding air: four times increase in heat-exchange coefficient (i.e. from 1°С/hour up to 4°С/hour) results in 20% growth of thermal capacity of the cooling subsystem system at similar ambient air temperature (it varies from 30°С up to 36 °С) if the maintained target indoor temperature is 22°С.

Comparative Simulation Analysis of Electric Vehicle Powertrains with Different Configurations Using AVL Cruise and MATLAB Simulink

Electric vehicles are now recognized as a crucial answer in the worldwide effort to achieve sustainable and environment-friendly transportation. As the automotive industry moves towards using electric power, it is crucial to assess and improve the powertrain configurations in electric vehicles. This study aims to meet this need by conducting an in-depth comparative analysis of single, double, and quad electric vehicle powertrain systems. The performance of these configurations is rigorously simulated by using two widely used platforms: AVL Cruise and MATLAB Simulink. This study mainly covers the analysis of energy efficiency, which is a critical factor in determining the environmental impacts and feasibility of electric vehicles. In order to conduct a thorough comparison, the energy consumption per kilometer is evaluated as a crucial performance measure. Our research primarily focuses on model validation, namely by comparing it with manufacturer data to determine the accuracy and reliability of the simulation results. The findings reveal a compelling narrative in the pursuit of sustainable transportation. The use of a dual motor setup stands out as a prominent example of energy efficiency, demonstrating remarkable outcomes in both simulation platforms. Significantly, these findings closely correspond with the manufacturer's data for the Volvo XC40, confirming the appropriateness and dependability of our simulation models. Furthermore, the quad motor configuration shows significant energy efficiency, providing helpful insight regarding its applicability and performance. The broader implications of this research go beyond powertrain configurations, including the trustworthiness of simulation models in the automotive industry. These findings improve the continuous advancement of electric vehicle design and development, indicating a more environment-friendly and energy-efficient future for the automotive industry. This study offers invaluable insights and benchmarks for the transition to environment-friendly transportation solutions, as the world advances towards sustainable mobility.

Energy efficiency and energy depletion analysis in oil-exporting developing countries

Energy efficiency and energy depletion analysis in oil-exporting developing countries

Multivariate optimization effectiveness model of single-longitudinal-mode laser under pre-laser Q-switching regime

The optimal effectiveness model for optimizing the system parameters was established in this study by combining the optimization function based on the pre-laser Q-switching technique. By introducing boundary conditions to solve the rate equations, the specific process of composite mode selection is analyzed, and the specific pre-laser modulation time interval that enables single-longitudinal-mode laser output is obtained. Furthermore, through the established efficiency evaluation function for single-longitudinal-mode laser output characteristics, with the maximization of single-pulse energy as the objective, an energy efficiency analysis of relevant parameters in the mode selection components is conducted. The model we have established is universal, which can accurately control the pre-laser Q-switching process and reveals the inherent logical relationship of the relevant parameters in composite mode selection. The output characteristics of a single-longitudinal-mode Q-switching laser can be predicted and adjusted under the condition of high pump injection. Both simulation and experimental results confirm the effectiveness of the model.