Potential For Energy Efficiency Improvement Research Articles

AbSolut - Integration of Absorption Technologies in District Heating and Cooling Systems for Enhanced Economic and Ecological Impact

District heating (DH) systems play a crucial role in meeting heating demands across the European Union (EU) and Austria, with significant potential for energy efficiency improvements and decarbonization. However, the transition towards climate neutrality by 2040 poses significant challenges, particularly in decarbonizing existing DH systems and integrating renewable energy sources. This work explores the application of absorption technologies, specifically absorption heat exchangers (AHX), absorption chillers (AC), and absorption heat pumps (AHP), in optimizing DH systems. The study investigates the utilization of AHX as transfer substations to increase heat capacity within existing grids by up to 30%, facilitating the integration of renewables and reducing distribution heat losses. Additionally, AC implementation for cooling supply demonstrates efficiency improvements through dynamic operation modes, renewable energy integration, and reduced electricity demand. Furthermore, AHP for waste heat utilization in DH power plants showcases environmental benefits, cost savings, and enhanced energy security. Through detailed techno-economic analyses and case studies, the paper evaluates the viability and economic feasibility of absorption technologies in DH applications. Challenges such as system integration, spatial requirements, and driving energy optimization are addressed, offering insights into overcoming barriers to adoption. Overall, the research highlights the transformative potential of absorption technologies in enhancing the efficiency, sustainability, and resilience of DH systems. By leveraging these technologies, DH operators and stakeholders can navigate the transition towards climate neutrality, while ensuring reliable and cost-effective heating and cooling solutions for urban areas.

Identifying barriers and drivers for energy efficiency in steel and iron industries of Karachi, Pakistan: Insights from executives and professionals

Pakistan has faced a persistent energy deficit over the past few decades, with energy-intensive industries occupying a substantial share of energy consumption. Despite the potential for energy efficiency improvements within the industrial sector, numerous barriers hinder progress. This study identifies the barriers and drivers of energy efficiency practices specifically within the steel and iron industries of the economic hub of Pakistan. Through a questionnaire-based approach and follow-up interviews, responses were gathered from 32 executives and professionals within the steel sector, representing eight firms. Reliability analysis was conducted to ensure the robustness of the data. The analysis reveals that limited awareness and inadequate managerial commitment are significant barriers to energy efficiency initiatives. Moreover, ineffective policies and a lack of government implementation plans contribute to diminishing demand for energy-efficient technologies. However, there is a growing interest among respondents in reducing energy consumption to enhance cost-effectiveness. Key drivers such as long-term economic benefits, improved working conditions, and cost savings emerge as crucial factors motivating the adoption of energy-efficient practices. Positively, some companies have already initiated energy-saving measures, including the adoption of advanced technologies and renewable energy sources. These findings highlight the urgent need for collaborative efforts to overcome barriers and promote sustainability in steel and iron sector of Pakistan.

Orthogonal design optimization for Cu/Sn58Bi-0.4Mg/Cu solder joint strength in ultrasonic-assisted soldering

This study investigated the influence of three ultrasonic-assisted soldering process parameters, namely soldering temperature, ultrasonic duration, and ultrasonic power, on the strength of Cu/Sn58Bi-0.4Mg/Cu solder joints. A three-factor, three-level orthogonal experiment was conducted by us using an L9 (34) orthogonal design, and the research outcome was evaluated in terms of solder joints shear strength. The optimal experimental design was determined through range analysis, and the Analysis of Variance (ANOVA) was performed to assess the individual impacts of each factor on the experimental results. Furthermore, we employed scanning electron microscopy (SEM) to examine the microstructures of the solder joints, investigate the progression of intermetallic compounds (IMC), and analyze the fracture surface morphology. Furthermore, we conducted essential Energy Dispersive Spectroscopy (EDS) elemental analysis to study the diffusion and distribution of elements. Finally, validation experiments were performed to compare the optimal design from the orthogonal experiment with the design derived from theoretical analysis, revealing that the latter yielded superior results. This study has identified an excellent set of parameters for ultrasonically assisted Cu/Sn58Bi-0.4Mg/Cu bonding. It offers novel insights into parameter selection for ultrasonic-assisted soldering, with potential energy conservation and efficiency improvement benefits.

A machine-learning assisted multi-cluster assessment for decarbonization in the chemical fiber industry toward net-zero: A case study in a Chinese province

China has pledged to achieve carbon neutrality by 2060, requiring deep decarbonization in its manufacturing sector, aligning with sustainable development goals such as climate action and responsible production. Notably, China's chemical fiber industry contributes over 70% of global production, facing challenges in net-zero transition due to differences in enterprise scale and energy efficiency. This study proposed an assessment framework for the decarbonization pathway for this type of manufacturing industries, use the chemical fiber industry as a case study. A hybrid model based on machine learning was introduced to predict the industry's energy consumption, while multiple-cluster standards were established to assess energy efficiency improvement potential. Monte Carlo simulation was employed to analyze the carbon trading impact on industry decarbonization. Using a Chinese province's chemical fiber industry as a case, results suggest its carbon emissions could reach 1.58 × 107 tCO2 by 2030, and energy efficiency enhancements could reduce emissions by approximately 22.6%. Achieving carbon neutrality would cause the industry to reduce profits by approximately 10%∼15% on higher-priced emissions trading system (ETS), unless additional carbon reduction techniques are adopted. This assessment framework can be applied to study decarbonization transitions in other manufacturing industries.

DIGITAL TWIN VALUE IN INTELLIGENT BUILDING DEVELOPMENT

The aim of the research. This article discusses the use of the Digital Twin in automation and its impact on the resulting solution. The research aims to illuminate the Digital Twin concept explanation and systematise the knowledge base and fulfill information gaps. Research results. The paper overviews the history of the concept and determines the main phases of Digital Twin development. The significant attention was paid to the classification issue to show the huge variation depending on Digital Twin‘s purpose, lifecycle phase, the scale of the physical twins and data amount in order to explain the twin‘s relation and the hierarchy of complex system. The defined capabilities and values of the concept identify the possible use cases and explain the potential benefits of Digital Twin implementation. Also, this paper takes a look at the use of Digital Twin in the area of building automation. This concept potentially may act as the integration platform for building management systems (BMS) and building information modelling (BIM) technologies with IoT solutions. The discussion of Digital Twin implementation for the building automation complex is presented. We conclude that the Digital Twin can integrate human factor to the control system by using the indexes of climate satisfaction, the feedback functionality and human-machine interfaces. As a result, the improvement of system efficiency depends on the coordination and orchestration of equipment operating mode. Conclusion. The Digital Twin has a high potential for energy efficiency improvements, as it considers many factors, integrates a huge amount of data and continuously improves themselves with real-world data.

Investigating energy saving and climate mitigation potentials in cement production – A case study in Ethiopia

The cement industry is one of the most energy and emission-intensive sectors, accounting for approximately 7% of total-industrial energy use and 7% of global CO2 emissions. This study investigates the potential energy savings and CO2 abatement in the cement plants of Ethiopia. A Benchmarking and Energy Saving Tool for Cement is used to compare the energy use performance of the individual cement plants to best practices. The study reveals that all the surveyed plants are less efficient, with an average energy saving potential of 36% indicating a significant potential for energy efficiency improvement. Then, twenty-eight energy efficiency measures are identified and analyzed using a bottom-up energy conservation supply curve model. The results show that the cost-effective electrical energy and fuel-saving potentials of these measures are estimated to be 99 Gigawatt hours per year which is about 11.5% of the plants’ annual electrical energy consumption and, 2.7 Petajoules per year which is to be 12.5% of the plants’ annual fuel consumption, respectively. The cost-effective fuel measures have an annual average CO2 emission reduction potential of 254 kilo-tonnes per year which covers about 5% of the total CO2 emission. Sensitivity analysis is conducted using the key parameters that show some discrepancy in the base case results. This study could be used as a reference for policymakers to understand the potential for energy savings and CO2 abatement. It could also be used to design policies in improving energy efficiency in the cement sector.

Machinery import, R&D spillover, and energy efficiency

The gap in demand and supply of energy across Sub-Saharan African (SSA) countries has increased energy insecurity in the region. Therefore, power outages have become pervasive, causing unemployment and a decline in production output. Among the several energy-saving factors identified in the literature across developing economies, technological spillover driven by trade openness appears to be a prominent factor in improving energy efficiency. Thus, this study evaluates the impact of machinery imported from OECD and non-OECD countries and its corresponding research and development (R&D) spillover on energy efficiency performance in 18 SSA countries from 1995 to 2017. Using a stochastic energy distance function, we discover that aggregated data from OECD and non-OECD countries have no significant effect on energy efficiency performance across SSA countries. However, results from disaggregated data for OECD and non-OECD machinery imports show that OECD machinery imports improve energy efficiency contrary to non-OECD imports. Thus, technology spillover from OECD countries is advantageous for SSA countries to reduce long-term energy-based emissions. Furthermore, our results show that human capital has no significant effect on SSA energy efficiency. Consequently, the results possess some policy implications; for instance, policymakers responsible for promoting science and technology could increase investment in human capital development by developing technology and engineering expertise and increasing GDP allocation to R&D activities. For energy efficiency scores, we observe substantial differences in efficiency across SSA countries – implying potential improvements in energy efficiency across SSA countries.

Research on exhaust energy distribution regulation for fuel economy improvement of turbocompound diesel engine

The stringent requirements for reducing CO2 emissions from internal combustion engines promote the development of waste heat recovery (WHR) technologies. Turbocompounding is a promising WHR technology offering fuel-saving potential along with low volume and weight requirements. Meanwhile, the exhaust energy distribution regulation plays a significant role in improving the engine fuel economy. In this study, the coupling influence and mechanism of the variable geometry turbocharger (VGT) turbine and power turbine (PT) regulation on the recovery power and engine performance were studied from novel perspective of exhaust energy distribution. And the cooperative control strategies of VGT rack position and PT speed under whole operating conditions were first proposed. It is concluded that the increase in the VGT rack position and the PT speed leads to a decrease in the proportion of exhaust energy distributed to the VGT turbine, which affects the intake and exhaust conditions, resulting in changes in PT power and net engine output power. In addition, as the engine speed increases under full load, the optimal VGT rack position and PT speed increase. Compared to the base engine, the equivalent brake specific fuel consumption can be reduced by 3.8% at the engine speed of 2200 r/min with the optimized control of the exhaust energy distribution for the turbocompounding. The control strategy of exhaust energy distribution is of great significance to explore the maximum potential of energy efficiency improvement of turbocompound diesel engines.

ENERGY EFFICIENCY OF THE WOOD-BASED PROCESSING MSMES IN THE NIŠ REGION

In the Niš region, there are 185 companies involved in the treatment or manufacture of wood and wood-based products. According to the national register of enterprise activity classification, 22.7 percent of micro, small and medium enterprises are engaged in the business of wood cutting and processing, 27.03 percent are in the business of construction carpentry production, 29.73 percent are in the business of wood packaging production, 2.7 percent are in the business of pellet production, and 32.43 percent are in the business of other wood treatment production or services. This article uses a preliminary energy audit assessment technique to address the concerns of potential improvements in competitiveness, energy efficiency, and waste wood biomass use potentials in selected representatives of the indicated company groups from the Niš region. Energy usage benchmarks are established based on the audits of the selected sample enterprises.

Can conversion of CO2 into fuels via electrochemical or thermochemical reduction be energy efficient and reduce emissions?

Electrochemical and thermochemical conversion of CO2 into fuels are significant carbon conversion technologies to mitigate carbon emissions. Based on the captured CO2, many previous studies carried out tech-economic and environmental analyses for the CO2 conversion systems. However, it is unclear about the energy efficiency and emission reduction of the full-chain system after applying carbon conversion technologies to the carbon sources such as coal power plants and chemical industries. With a unified coal-fired power plant as the carbon source, this study conducted a full-chain systematic analysis of three representative CO2 conversion technologies (shown as routes 1, 2, and 3). Routes 1, 2, and 3 converted the emitted CO2 into fuels via CO2 electrolysis, MEA-CO2 electrolysis, and CO2 hydrogenation. The performance of three Routes in terms of energy efficiency and carbon emissions was comprehensively analyzed. And this work also investigated the energy efficiency improvement potential of three Routes. The results indicated that the energy efficiency of Route 1 was the greatest. And Route 2 exhibited optimal emission reduction. The core factors for enhancing the performance of full-chain systems were improving the efficiency of photovoltaic power generation and developing low-energy-consumption CO2 absorbents. The results also indicated that to date, from the perspective of converting CO2 into the fuel gas CO, no Routes had advantages over coal power plants with carbon capture and storage (CCS) or syngas production directly from coal gasification in terms of energy efficiency and carbon emissions. However, converting CO2 into high-value-added products might be more significant for integrating carbon emission reduction and storing renewable electricity.

An integrated collaborative decision-making method for optimizing energy consumption of sail-assisted ships towards low-carbon shipping

Energy conservation and emission reduction have become an urgent and important issue for the shipping industry in the context of low-carbon shipping. For sail-assisted ships, the application of wind energy can reduce energy consumption and thus greenhouse gas emissions. However, there still exists a high potential for energy efficiency improvement due to the lack of an effective optimization method for maintaining the hybrid system operating at the optimal state continuously. In this paper, a novel integrated collaborative decision-making method, considering the coupling influence of the sailing path, speed, wing-sail's angle of attack, and various environmental factors, is investigated to achieve energy conservation and emission reduction for sail-assisted ships. First, an integrated collaborative optimization model of the sailing path, speed, and sail's angle of attack is established. On this basis, a PSO-based integrated collaborative decision-making method for simultaneous optimization of sailing path, speed, and sail's angle of attack under various operational conditions is proposed. The study results show that the proposed method is capable of fully utilizing wind energy, meanwhile maintaining the hybrid power system operating at the optimal state under various operational conditions, and can reduce energy consumption and CO2 emissions by approximately 8.9% for a voyage.

Energy efficiency improvement potentials through energy benchmarking in pulp and paper industry

This study aims to highlight the energy improvement potentials of Pakistan's paper sector that is one of the most energy intensive industries by benchmarking its specific energy consumption (SEC) to produce a similar grade of paper. To address issues such as the lack of indicators for energy efficiency benchmarking in Pakistan's paper industry. Furthermore, energy saving potential was estimated by comparison with paper industries in the United Kingdom and Canada, where energy benchmarks have already been established and data on energy benchmarking is readily available. This study energy consumption data accounts for 75% of the total energy utilized in Pakistan's paper industry and is compared with the energy consumption of the UK and Canada paper sectors where the most up-to-date energy-saving techniques are used. The calculation shows that when compared to the paper industries in the UK and Canada, Pakistan's paper industry utilizes an additional 1.3 MWh of energy for every tonne of paper produced. With a total yearly paper production of 314,549 metric tonnes, this equates to an additional 408,913 MWh of overall annual energy use. It is concluded that if the proposed energy benchmark in this study is applied within the country's mill comparison, savings of 16.4% of overall energy consumption in the Pakistan paper sector can be achieved. It is also shown that the implementation of the best available techniques used in the UK and Canada in Pakistan's paper sector could result in a potential energy saving of 43% of the total energy consumed by this sector.

Energy Efficiency Optimization for Machining of Wood Plastic Composite

Enhancing energy efficiency is the key to realizing green manufacturing. One major area of interest in this regard is the improvement of energy efficiency of machine tools during the production of building materials. This project focuses on energy efficiency during the spiral milling of wood plastic composites. To this end, a response surface method was adopted to develop a model and establish the relationship between energy efficiency and milling conditions. Analysis of variance based on individual factors as well as two-factor interactions was performed to gauge their effects on energy efficiency. It was found that milling depth was positively correlated to power efficiency, while spiral angle and feed per tooth displayed non-monotonic behavior. An attempt was made to predict milling conditions that will yield the greatest material removal rate and power efficiency. For wood plastic composites subjected to up-milling, it was determined that a feed per tooth of 0.1 mm, milling depth of 1.5 mm, and spiral angle of 70° were ideal. Considering the potential improvements in energy efficiency and surface quality that these process parameters will bring, it is strongly recommended for use in the industrial machining of wood plastic composites.

An overview of machine learning applications for smart buildings

The efficiency, flexibility, and resilience of building-integrated energy systems are challenged by unpredicted changes in operational environments due to climate change and its consequences. On the other hand, the rapid evolution of artificial intelligence (AI) and machine learning (ML) has equipped buildings with an ability to learn. A lot of research has been dedicated to specific machine learning applications for specific phases of a building's life-cycle. The reviews commonly take a specific, technological perspective without a vision for the integration of smart technologies at the level of the whole system. Especially, there is a lack of discussion on the roles of autonomous AI agents and training environments for boosting the learning process in complex and abruptly changing operational environments. This review article discusses the learning ability of buildings with a system-level perspective and presents an overview of autonomous machine learning applications that make independent decisions for building energy management. We conclude that the buildings’ adaptability to unpredicted changes can be enhanced at the system level through AI-initiated learning processes and by using digital twins as training environments. The greatest potential for energy efficiency improvement is achieved by integrating adaptability solutions at the timescales of HVAC control and electricity market participation.

Application of solid lubricant for enhanced frictional efficiency of deep drawing process

Manufacturing processes are usually energy intensive, contributing to the global carbon dioxide emissions. Deep Drawing is one of the most common types of sheet metal forming processes with great potential for energy efficiency improvement. In this paper, the optimised combination of molybdenum disulphide (MoS2) and graphite is proposed as a solid lubricant to reduce the punching force and energy consumption of deep drawing process. Different mixtures of MoS2 and graphite are prepared and their tribological performance are measured using experimental tests on tribometer. In order to investigate the friction reduction rate in deep drawing process, finite element simulation of the drawing process is performed. Results show that friction reduction using proposed combination of lubricants has significant effect on punching force and would provide greater process efficiency.

The Evaluation of Energy Efficiency Policies in the Building Sector: A Regional Analysis Based on the Stochastic Frontier Approach and on the Energy Environmental Kuznets Curve (EKC) and Policy Implications

The promotion of the Energy Efficiency is one of the priorities of EU energy policy to fight the Climate Change and make Europe climate neutral by 2050 (EC 2020). The civil sector offers high potential for energy efficiency improvement and the buildings are responsible for about 40% of the EU's energy consumption, and 36% of greenhouse gas emissions (EC 2020). In Italy the civil sector (residential and tertiary together), are responsible for approximately 45% of final energy consumption and 17.5% of Italy's CO2 emissions, has a potential in reducing energy consumption of approximately 5,7 Mtoe compared to the base scenario in 2030. The core research question is: “Are national and local energy efficiency policies effective in reducing aggregate energy consumption at regional level in the civil sector?” From the policy maker’s point of view, it is important to understand the effectiveness of the policy instruments introduced to promote energy efficiency. The research framework is based on the frontier analysis and its main objective is to econometrically estimate for the period 2010 to 2017 the energy efficiency level for the civil sector in the Italy regions. The estimates confirm the effectiveness of policy instruments, represented by tax deductions and economic incentives, in creating high potential for energy savings from reduced inefficiency in the civil sector.

A sustainable syngas cryogenic separation process combined with ammonia absorption refrigeration pre-cooling cycle

With the goal of effectively utilising low-grade waste compression heat by investigating potential improvements in energy efficiency, this study proposed a novel syngas liquefaction process combined with an ammonia absorption refrigeration cycle driven by available low-grade compression heat. The systems were evaluated from thermodynamics, as well as techno-economic aspects, to reduce the energy consumption and greenhouse gas emission. This study attempted to tackle two vital issues: how to effectively convert low-grade compression heat to cooling capacity to improve energy efficiency and design refrigeration cycles (both ammonia absorption refrigeration cycle and main refrigeration cycle) tailored with Heat Integration. The process was modelled, simulated, and optimised, aiming to reduce refrigerant and energy. The case study results demonstrated that the syngas liquefaction process with ammonia absorption cycle dramatically reduced the refrigerant consumption by 15.3%, contributing to a 7 MW reduction in electricity consumption. The specific energy consumption was decreased from 3.2 to 2.36. The coefficient of performance increased from 0.11 to 0.14. As for the environmental effect, the total greenhouse gas emissions were decreased from 0.12 Mt CO2-eq to 0.09 Mt CO2-eq. The exergy analysis showed that the new process decreased the total exergy destruction by 6.7 MW, leading to a higher exergy efficiency of 54.5%. In view of the economic performance, the total capital investment and total product cost were lowered by 10.8% and 20.1%. The proposed syngas liquefaction process exhibited the significant potential to improve environmental, thermodynamic, and techno-economic performances. The sensitivity analysis showed that the product cost of the new process was less sensitive to the variation of the electricity price.

Energy‐efficient full‐duplex UAV relaying networks: Trajectory design for channel‐model‐free scenarios

In this paper, we propose an energy-efficient unmanned aerial vehicle (UAV) relaying network. In this network, the channels between UAVs and ground transceivers are model-free. A UAV acting as a flying relay explores better channels to assist in efficient data delivery between two ground nodes. The full-duplex relaying mode is applied for potential energy efficiency (EE) improvements. With the genetic algorithm, we manage to optimize the UAV trajectory for any arbitrary radio map scenario. Numerical results demonstrate that compared to other schemes (eg, fixed trajectory/speed policies), the proposed algorithm performs better in terms of EE. Additionally, the impact of self-interference on average EE is also investigated.

Evaluation of the Energy Efficiency Improvement Potential through Back-End Heat Recovery in the Kraft Recovery Boiler

Sustainability and energy efficiency have become important factors for many industrial processes, including chemical pulping. Recently complex back-end heat recovery solutions have been applied to biomass-fired boilers, lowering stack temperatures and recovering some of the latent heat of the moisture by condensation. Modern kraft recovery boiler flue gas offers still unutilized heat recovery possibilities. Scrubbers have been used, but the focus has been on gas cleaning; heat recovery implementations remain simple. The goal of this study is to evaluate the potential to increase the power generation and efficiency of chemical pulping by improved back-end heat recovery from the recovery boiler. Different configurations of heat recovery schemes and different heat sink options are considered, including heat pumps. IPSEpro simulation software is used to model the boiler and steam cycle of a modern Nordic pulp mill. When heat pumps are used to upgrade some of the recovered low-grade heat, up to +23 MW gross and +16.7 MW net power generation increase was observed when the whole pulp mill in addition to the boiler and steam cycle is considered as heat consumer. Combustion air humidification proved to yield a benefit only when assuming the largest heat sink scenario for the pulp mill.

Measuring environmental-adjusted dynamic energy efficiency of China’s transportation sector: a four-stage NDDF-DEA approach

The energy consumption and CO2 emissions of the transportation sector in China have increased greatly in recent years, accompanied by the growing regional disparities. Considering undesirable output and environmental impact factors, a four-stage DEA (data envelope analysis) combined with NDDF model (non-radical directional distance function) is adopted in this paper to calculate the energy efficiency and eliminate the environmental impacts of Chinese transportation sector. In this paper, five environmental factors are considered, including GDP per capita, consumption level, urbanization level, economic openness level, and transport infrastructure. The empirical results on the panel data for 30 provinces of China from 2005 to 2016 show that the energy efficiency of the transportation sector in China decreases from Eastern to Western region. After the adjustment of environmental factors, energy efficiency still shows a decreasing trend from Eastern to Western region, while energy efficiency increases more in Eastern region and less in Central region and Western region. The potential of energy efficiency improvement for some Central and Western provinces is relatively high. Some policy suggestions are proposed to improve the energy efficiency of Chinese transportation sector.