Definition Of Energy Efficiency Research Articles

ЗАБЕЗПЕЧЕННЯ ЕНЕРГОЕФЕКТИВНОСТІ ЕКОНОМІКИ: МОЖЛИВОСТІ ІМПЛЕМЕНТАЦІЇ ЗАРУБІЖНОГО ДОСВІДУ

The author’s definition of energy efficiency of the economy has been proposed in the article. The main indicators of energy efficiency, which determine the rating of Ukraine among other countries of the world, have been analyzed. It is emphasized that the introduction of martial law in Ukraine and the full-scale war significantly affected the energy efficiency of Ukraine’s economy due to the destruction of many energy infrastructure facilities. Attention is focused on the need to organize a systematic and standardized increase in the efficiency of the use of energy resources in domestic production systems. Based on the use of statistical information of the World Economic Forum, the indicators of energy saving efficiency of the countries of the world and their rating have been given. The foreign experience of using modern smart technologies and the main tools for ensuring energy efficiency of the economy have been studied. The authors stress that energy efficiency contributes to the reduction of energy consumption. The growing world population and rapid economic growth lead to increased energy consumption. However, many countries face challenges related to limited resources and growing energy dependence. Energy efficiency can help reduce dependence on energy imports and provide a more sustainable and efficient economy. The expediency of implementing modern technologies and tools of ensuring energy efficiency as a factor in the future revival and development of the economy of Ukraine has been proven. It has been substantiated that in modern conditions, Ukraine needs to change the policy of energy consumption and energy supply as soon as possible, maximizing the consumption of fuel and energy resources, which the country is rich in (coal, nuclear fuel, renewable sources), and accordingly reducing the consumption and import of natural gas - the most expensive and scarce resource. It is noted that in order to ensure the energy efficiency of residential construction, it is necessary to lay down energy-saving technologies and new energy-saving methods at the design stage. The introduction of martial law and full-scale war significantly affected the energy efficiency of Ukraine’s economy due to the destruction of many energy infrastructure facilities. A decrease in energy efficiency can have serious consequences for the country’s economy, in particular, an increase in the cost of energy resources, a decrease in the competitiveness of enterprises, and a threat to the stability of electricity supply to the population and industry. The destruction of energy infrastructure facilities, such as power plants, transformer substations, gas pipelines and oil pipelines, can lead to a decrease in energy production capacity and a deterioration in the quality of supply. This can cause problems with electricity supply, heating, education, maintenance of industrial enterprises and infrastructure. In connection with the explosion by the russian occupiers of the Kakhovskaya HPP, the Ministry of Energy initiates the decision to increase electricity imports from the EU to 2 GW. On the other hand, military actions on the territory of Ukraine may lead to a decrease in investments in the field of energy efficiency and the development of renewable energy sources, priority is given to military needs and the restoration of damaged infrastructure.

Numerical modelling for design of microchannel reactors: Application to hydrogen production from methanol by steam reforming

Microchannel reactors involve chemical-reaction engineering problems in their design and operation, with heat and mass transfer considerations dominating their practicability and efficiency. Study of the fundamental transport phenomena necessitates their description in sophisticated mathematical form. The present study seeks to address this particular problem by investigating the effects of various factors on the transport processes in a heterogeneously catalysed microchannel steam reforming reactor. Numerical modelling for reactor design was performed using a model that accounted for complex catalyst dynamics. Dimensionless number analyses were conducted to understand the nature of the transport processes. The reactor performance was evaluated by means of various parameters, and design recommendations were made. Different operating limit lines were mapped out, and various definitions of energy efficiency were distinguished. The results indicated that the use of microchannel technology enables the achievement of unusually favourable conversion. While mass-transfer limitations are dominant, the reaction is practically feasible at millisecond contact times. A maximum output power in excess of 70 watts per channel can be reached, and energy efficiencies up to about 70 percent are available. The operating limit line can be changed as desirable to maintain the desired product yield throughout the range of conditions. While an optimum velocity for maximum efficiency exists, the flow rate and catalyst loading must be carefully adjusted to simultaneously control the conversion and maximum power within certain needed limits.

Study on the combined use of solar and water energy in power supply systems

This article discusses the development of a system for the combined use of solar and water energy based on a systematic approach to power supply. An improved physical model has been developed based on a model for predicting the production of electricity, taking into account the power and time of solar radiation, the amount and speed of water flow. At the same time, the share of electricity in the use of solar and water energy was determined simultaneously, depending on the conditions for the uninterrupted supply of consumers with the daily necessary electricity. The assessment of indicators of the combined use of solar and water energy and the definition of energy efficiency were developed by the authors on the basis of an increase in the share of electricity obtained from renewable energy sources in the electricity supply, which is explained by the coincidence of theoretical and experimental results.

Parametric study of a regenerative heat exchanger for ventilation with a periodic change in the air flow direction

A two-dimensional mathematical model of a regenerative heat exchanger for a ventilation system with a periodic change in the air flow direction is developed. This system allows a significant economy of the thermal energy for heating buildings in winter. Such devices are quite compact, has no moving details and do not require significant electrical power for their operation, while they can provide the ventilation needs of both whole buildings and individual rooms in multi-storey buildings. The definition of energy efficiency of a regenerative heat exchanger is formulated in terms of reducing the loss of thermal energy. It is shown, that regenerative heat exchanger can really reduce thermal energy losses by ventilation more than by 90%. Parametric studies are fulfilled using the method of numerical simulation and the influence of operating and design parameters of the heat exchanger on its energy efficiency is revealed. In numerical calculations, a group of parameters that most strongly affect the energy efficiency of the ventilation system is identified, and recommendations for optimizing these parameters are given.

Сучасні підходи до оцінювання енергоефективності національної економіки

The article notes that energy efficiency cannot simply be a vague and ambiguous concept that does not have accurate assessment methods. It should have clear measurements and evaluation methods. When the question arises as to measuring or evaluating, the lack of a clear definition of energy efficiency can cause the results to differ and it will be difficult to compare them depending on the needs or objectives. So the need to develop an accurate and unified definition of energy efficiency, as well as its classification and development of measurement methods is highlighted. It is emphasized that highly developed countries of the world have significant experience in achieving a high level of energy efficiency of national economies, but they also do not currently have developed a unified system of energy efficiency indicators at the national level, methods for their assessment and analysis. The energy intensity of GDP is almost the only universal instrument by which international and regional comparisons of energy efficiency levels of national economies are possible. It is shown that in recent years in Ukraine there has been a clear tendency to reduce the energy intensity of the national economy in almost all spheres. The State Agency on Energy Efficiency and Energy Saving of Ukraine has developed tables of primary data and a methodology for calculating energy efficiency indicators of the Ukrainian economy. Primary data and calculation indicators are formed by such sectors as industry, transport, housing, agriculture, services. The article shows that recent methods for evaluating energy efficiency based on modeling the efficiency limit, namely, DEA and SFA models, have become a popular tool for evaluating energy efficiency. Despite a number of its advantages, the DEA method does not take into account statistical noise. In contrast to DEA models, SFA models use the Shepard distance function to determine the energy efficiency index and take into account statistical noise.

Energy efficiency in mechanical pulping – definitions and considerations

Abstract Production of mechanical pulps requires high specific electrical energy compared to many other attrition processes. In Scandinavia, the lowest specific refining energy for production of thermomechanical pulp is around 1800 kWh/t for newsprint quality, which is roughly 60 times higher than for crushing of stone to a similar size distribution. The high specific energy demand for refining has naturally motivated large efforts in the search for improved efficiency. It is always practical to be able to quantify improvements in efficiency for comparison of process designs and of different machine types. However, there is no commonly accepted definition of efficiency for mechanical pulping processes. In published work within mechanical pulping, energy efficiency has been presented in different ways. In this paper, we discuss definitions of energy efficiency and aspects that ought to be considered when energy efficiency is presented. Although focus of this work is on energy efficiency for refiner processes, the principles can be applied to other types of mechanical pulping processes such as stone groundwood.

Financing the (Environmental) Quality of Cities with Energy Efficiency Investments

The purpose of the paper is to study the financing models in order to drive the large amount of financial resources, already allocated for energy efficiency, to improve the quality of cities. These resources are being deployed worldwide by both public and private financial institutions. Energy efficiency is usually managed at the scale of the buildings, i.e., consumption reduction (heating, lighting, etc.). The study methodology is to review energy-efficiency finance (EEF) models, and assess them using multiple case studies. At the same time, the ownership of cities’ spaces is studied across public-private space management, as an effective methodology to bridge the gap between public and investor finance. The comparative analysis of the case studies suggests a paradigm shift in the definition of energy efficiency, not just in terms of the buildings, but instead also the local urban environment with its feedbacks on the quality of urban living. The practical implications are innovative EEF models, such as those being reviewed, which may be: (1) analytical, to assess the environment at the scale of blocks or neighbourhoods; (2) financial, to fund the specific scale; (3) relating to policy, to support and encourage. In recent years, support for urban regeneration is becoming particularly relevant, given the budget constraints of most public administrations and the conjunctural shortening of private partnerships.

A Survey on Energy-Efficient Strategies in Static Wireless Sensor Networks

A comprehensive analysis on the energy-efficient strategy in static Wireless Sensor Networks (WSNs) that are not equipped with any energy harvesting modules is conducted in this article. First, a novel generic mathematical definition of Energy Efficiency (EE) is proposed, which takes the acquisition rate of valid data, the total energy consumption, and the network lifetime of WSNs into consideration simultaneously. To the best of our knowledge, this is the first time that the EE of WSNs is mathematically defined. The energy consumption characteristics of each individual sensor node and the whole network are expounded at length. Accordingly, the concepts concerning EE, namely the Energy-Efficient Means, the Energy-Efficient Tier, and the Energy-Efficient Perspective, are proposed. Subsequently, the relevant energy-efficient strategies proposed from 2002 to 2019 are tracked and reviewed. Specifically, they respectively are classified into five categories: the Energy-Efficient Media Access Control protocol, the Mobile Node Assistance Scheme, the Energy-Efficient Clustering Scheme, the Energy-Efficient Routing Scheme, and the Compressive Sensing--based Scheme. A detailed elaboration on both of the basic principle and the evolution of them is made. Finally, further analysis on the categories is made and the related conclusion is drawn. To be specific, the interdependence among them, the relationships between each of them, and the Energy-Efficient Means, the Energy-Efficient Tier, and the Energy-Efficient Perspective are analyzed in detail. In addition, the specific applicable scenarios for each of them and the relevant statistical analysis are detailed. The proportion and the number of citations for each category are illustrated by the statistical chart. In addition, the existing opportunities and challenges facing WSNs in the context of the new computing paradigm and the feasible direction concerning EE in the future are pointed out.

Energy-Efficient Resource Allocation With Flexible Frame Structure for Hybrid eMBB and URLLC Services

The key objective of the fifth generation (5G) wireless technology is to support services with highly diverse requirements, which necessitates the specification of flexible numerology and frame structure for radio resource allocation in 5G new radio (NR). In this article, flexible 2-dimensional resource allocation is investigated to exploit the frequency and time diversities of the resource grid, and eventually maximize the overall system energy efficiency (EE) in the scenario where enhanced mobile broadband (eMBB) and ultra-reliable and low latency communication (URLLC) services coexist. A new definition of EE is proposed to capture and fulfill the heterogeneous quality-of-service (QoS) requirements of eMBB and URLLC services. By first sliding a window on the resource grid to determine the candidate resource pool, and then allocating resource blocks (RBs) therein by leveraging linear programming (LP) relaxation, we propose a sliding window (SW) based algorithm with a low complexity for the NP-hard EE optimization problem. In addition, we also analyze the achievable EE performance of the proposed algorithm to demonstrate its scalability with respect to the grid sizes and the maximum transmit power to provide an in-depth understanding. Numerical results show that the proposed algorithm can bring about as much as 16.7% power consumption reduction, and improve EE by about 29.3% compared to other baseline systems.

Energy consumption and energy intensity of the Russian GDP, taking into account the development of the transport network

The article studies energy consumption and energy intensity of gross domestic product (GDP) in the Russian Federation. Primary energy consumption and the structure of fuel and energy resources consumption in the Russian Federation during 2015-2019 were studied, the analysis of the achievement of target energy intensity of the Russian GDP was carried out, the dynamics of curtailment on demand for fuel and energy resources based on the use of technology was studied. The authors’ definition of energy efficiency, a strategy for the development of energy efficiency, an information system for the optimization and improvement of energy efficiency are presented as a scientific novelty in this paper. The authors substantiated that the informatization of the energy and production structure of an enterprise is one of the issues in the area of energy preservation and energy efficiency development.

Energy-efficient indicators of panel housing mass construction in the climatic conditions of central Russia

For the design of energy-efficient buildings, it is only necessary to ensure balanced energy consumption. The definition of energy efficiency is inextricably linked to compliance with requirements and economic costs. The concept of energy efficiency does not only apply to a new building. The new design used all the necessary elements. The use of single-layer prefabricated panels in new construction allows for external insulation taking into account the overlap of all monolithic joints. One of the potentially promising methods of thermal insulation of outdoor structures is the use of liquid-ceramic (thermal insulation) coatings. In the course of the study, it was concluded that the surface temperature of the reinforced concrete panel when using two different insulation options has similar indicators. But the difference in the values of the heat flux is 36.2%, i.e. when using liquid-ceramic insulation, the amount of heat transferred through the wall panel is more by 9.67 W / m2. Economic calculation shows that the use of liquid-ceramic insulation has a positive economic effect in comparison with the classical method of wall insulation by 19.56%.

Energy Efficiency: Indicator, Estimation, and a New Idea

Energy efficiency has long been an important issue to the global economic and political theaters; however, searching for an effective and concise measure for efficiency remains a contentious and intriguing topic. There are two obvious flaws with the commonly used metrics in existing literature. First, there is a sense of confusion and misunderstanding between the definitions of energy efficiency and efficacy. As a result, the formulae and methods for measuring efficiency are often the subject of criticism. Second, even if the definition of efficiency is clear, the method of estimation can be quite cumbersome, making it difficult to comprehend or implement. This study attempts to address these two issues. With an OECD comparative dataset, it first presents the contradiction between efficiency and efficacy, explains the loss of effectiveness with the existing measurements, and then proposes a new and easy-to-use method for gauging energy efficiency, so that the succinctness and robustness of the measurement can be re-established. The paper serves as a guide to those who are interested in the controversial issues related to measuring energy efficiency. Both practitioners and policy makers will find an easy and reliable tool from this paper for measuring energy efficiency.

An Event-based Local Action Paradigm to Improve Energy Efficiency in Queriable Wireless Sensor Actuator Networks

Wireless sensor networks (WSN) are deployed in a multitude of applications both in industrial and academic fields. In recent years, due to the emerge of Internet of Things (IoT) technologies and Vehicle2X communication scenarios, novel challenges for wireless sensor network platforms - regarding hardware and software - arose. Thus, challenges known from big data processing have reached the WSN scope and consequently approaches and methods have been devised to handle these. One such approach is queriable wireless sensor networks which enable their users the specification of sensing tasks in a declarative way without the need to re-program nodes in case the application requirements change. As many current WSN applications feature active parts with which nodes can directly influence their environment, the term wireless sensor actuator networks (WSAN) has been coined, setting such networks apart from solely passively measuring networks.In this article, we will present a short introduction to big data processing in wireless sensor networks which motivates the usage of queriable networks. We will show that in order to enable a WSAN to carry out actions energy-efficiently and in a timely manner, an event-based action model is favorable. Additionally, we will demonstrate how such an event system can be used to improve sub query performance in WSNs. We conclude with an evaluation regarding the benefit of combining this approach with wake-up receiver technologies based on a qualitative energy efficiency definition for WSN.

The ANTAREX domain specific language for high performance computing

The ANTAREX project relies on a Domain Specific Language (DSL) based on Aspect Oriented Programming (AOP) concepts to allow applications to enforce extra functional properties such as energy-efficiency and performance and to optimize Quality of Service (QoS) in an adaptive way. The DSL approach allows the definition of energy-efficiency, performance, and adaptivity strategies as well as their enforcement at runtime through application autotuning and resource and power management. In this paper, we present an overview of the key outcome of the project, the ANTAREX DSL, and some of its capabilities through a number of examples, including how the DSL is applied in the context of the project use cases.

Identify Energy Savings Opportunities from Operational “Self-Help “and “Quick Fix” Optimization Approaches

The objective of this paper is to describe the importance of formation of a pragmatic Energy Optimization Program (EOP) at the concerned oil and gas facilities. Substantial amount of energy savings can be realized by focusing on initiatives that require no investment or so called “self-help” that can easily be implemented without further a due. A “quick fix” initiative involves a nominal investment; it can also be easily executed without the need for detailed project justification. Given the increasing expectations to oil and gas organizations to maintain a competitive edge in the modern global economy have caused the instability of crude oil as the world’s major commercial energy source for the next coming years and greater commitment to reduce greenhouse gas (GHG) emission. Regardless of during high or low crude oil price, energy is certainly a critical business continuity driver for both users and producers. Having significantly greater EOP to explore energy savings opportunities require many efforts including new efficient equipment, new technology, new processes and approaches which should be given a priority. Ideally, EOP focused team shall effectively participate in early design stage of project, so that all significant energy efficiency concepts will be considered in the design. In reality, many energy efficiency efforts may be missed out as a result of loose energy efficiency definition, less competency of design engineers, hectic project schedule and/or resource constraint.

Energy Efficient Power Allocation Scheme for Downlink Distributed Antenna System in Composite Fading Channel

In this paper, the energy efficiency (EE) of downlink distributed antenna system is investigated over composite fading channel including the path loss, shadow fading and Rayleigh fading, where both the static and dynamic circuit power consumptions are considered. Under the constraint of maximum transmit power of each remote antenna, our aim is to maximize the EE which is defined as the ratio of the transmission rate to the total consumed power to obtain effective power allocation (PA). According to the definition of EE, the optimized objective function is firstly formulated, and then utilizing the properties of fractional programming theory, the non-convex optimization problem in fractional form is transformed into an equivalent convex optimization problem in subtractive form, which makes the optimized problem become easy to handle. Based on this, using the Karush–Kuhn–Tucker conditions and mathematical calculation, an optimal energy efficient PA scheme is derived. Compared to the existing optimal schemes based on exhaustive search and the iterative calculation, this scheme may provide closed-form calculation of PA coefficients, and thus the computation complexity is lower. Moreover, it can obtain the EE performance identical to the existing optimal schemes. Simulation results verify the effectiveness of the proposed scheme.

Determination of energy efficiency for water heating in eight South African hotels

This study presents a characterization framework for energy efficient hotels. It builds on existing frameworks of energy efficiency and the adopted characterization framework advances from the input-output framework. The theoretical framework was developed through an in-depth literature analysis. In contrast with other frameworks, this framework incorporates a wide range of environmental and sustainable development tools. It accounts for both financial and physical energy use and services quality parameters. Subsequently, the framework was tested in eight star-graded hotels. The results presented are based on two issues (1) the theoretical formulation of an advanced energy efficiency model and (2) the empirical testing or application of the framework among eight hotels in the Mpumalanga province, South Africa. The findings of the study confirm that energy efficiency characterization should be based on the ability of a hotel to save energy while it continues to provide output services that at least comply with minimum services standards. Furthermore, the study revealed that the input-output framework was limited to the determination of the level of efficiency, but could not determine if an activity or institution was efficient. The study shows that the adopted framework builds on the existing definition of energy efficiency and other frameworks.

Embodied Energy and Nearly Zero Energy Buildings: A Review in Residential Buildings

Towards the EPBD recast 2010/31/EU and the nearly zero energy building (nZEB), this review addresses the whole life cycle energy analysis of residential buildings. Life Cycle Energy Analysis (LCEA) of 90 case studies of residential buildings is evaluated with a specific focus on the normalization procedure that follows the principles of Product Category Rule (PCR) 2014:02 for buildings. The normalization procedure provided a minimization of the sample by considering issues of comparability, the omissions in the boundaries of the system, the LCI method and the updating on the energy efficiency definition of the building. Results indicate that the use of different LCI methods leads to an important fluctuation in the absolute values of embodied energy as the embodied energy of annZEB calculated with process analysis is lower than every case study calculated with hybrid input-output analysis without including nZEBs. The share of embodied energy in low energy buildings could reach up to 57% -or even up to 83% when renewable energy sources are used for electricity production- and in nZEBs up to 100% even though a significant reduction in the total life cycle energy is identified. The increase in embodied energy and a difference of at least 17% in the share of embodied energy between low energy and nearly zero energy buildings indicate that maybe LCEA should be considered in energy efficiency regulations along with further standardization.

Research on Energy Efficiency Status of Fans in Zhejiang Province

The fan industry has developed rapidly because of the large demand in the fields of thermal power, metallurgy and so on. There are many manufacturers in Zhejiang Province. However, energy efficiency projects are not carried out sufficiently in those factories. Compared with foreign standards on fan energy efficiency such as ANSI/AMCA 205 and ISO 12759, national standard GB 19761 still has some disparity in the scope of application, the energy efficiency classification and definition of energy efficiency. Using the experience of foreign standards and vigorously promoting the energy efficiency projects in the fan manufacturing enterprises could accelerate the development of domestic standard system on fan energy efficiency and entire fan industry.

Energy Efficiency in Wireless Networks via Fractional Programming Theory

This monograph presents a unified framework for energy efficiency maximization in wireless networks via fractional programming theory. The definition of energy efficiency is introduced, with refere...