Energy consumption model and energy efficiency evaluation for CNC continuous generating grinding machine tools

Abstract

Machine tool, which is the basis energy consumed device in manufacturing system, its energy consumption model and energy efficiency evaluation are the prerequisites for energy saving in manufacturing. Considering the multi-energy-sources features，analysed the mathematical model of a CNC continuous generating grinding machine tool from the view of energy constitute. The energy sources of a CNC continuous generating grinding machine tool are classified into gear grinding system, grinding wheel dressing system and auxiliary system. Based on the power balance equations of energy flow, the energy flow system of a CNC continuous generating grinding machine tool is established. And then the energy consumption mathematical model of a CNC continuous generating grinding machine tool is set up by combining the power balance equations with the operating features of three kinds of energy sources. The case study shows that the proposed energy consumption model can provide fundamental support for energy consumption forecasting, energy efficiency analysis and energy-saving optimisation during the machine tool operation process.     

Exergy efficiency analysis of a refurbished dwelling: a case study in Ljubljana,Slovenia

Buildings contribute almost half of the world's carbon dioxide (CO₂) emissions. Energy and water consumption are some of the largest and fastest growing pressures on the global environment. The use of energy is mainly attributed to the heating and cooling of buildings. The type of materials used in the construction of buildings plays a significant role in the life-cycle emissions of each dwelling. Changing the material use in the construction of an existing building and adding insulation could have a major impact on energy use and the environment of the building in its entire life cycle. This paper investigates the amount of exergy savings and the decrease in CO₂ emissions resulting from the refurbishing of an existing building in Ljubljana. This study results from the growing awareness that in the choice of building materials, the designer must consider not only the requirements of the owner and occupier of the building, but also the resulting energy savings, the resource base and the effects of the manufacturing and processing of building materials on the environment. The exergy efficiency of the material use is calculated and the environmental impact assessment of energy and material use is accounted for.     

Research on Indicator System of Regional Eco-efficiency: A Case Study of Chengyang District

Abstract

Eco-efficiency is a valuable tool for managing and solving issues involving resource consumption and pollution emission in current production processes. Despite the popularity of the term “eco-efficiency” in business, limited attention has been paid to measuring and reporting regional eco-efficiency for local government policy makers. Based on the concept and method of eco-efficiency, an indicator system of regional eco-efficiency is established in this study. The indicator system comprises 22 indicators, which are divided in to three categories including socio-economic development, resources consumption, environmental pressure. As a promising statistical technique, principle component analysis is used to set the weight of indicators which attempts to calculate the eco-efficiency indices of Qingdao's Chengyang District. The results show that the eco-efficiency of Chengyang District has clearly improved 35.1% with small fluctuation from 1995 to 2003. Socio-economic development index and resources consumption index also represent obvious increasing trends. The correlation coefficient between soci-economic development index and resources consumption index is 0.979, which means the social progress and economic growth of Chengyang District depend on an extravagant consumption of resources. The environmental pressure index in- creased slowly before 1997 and declined gradually after 1997, due to more attention being paid to environmental protection by local government in recent years. Chengyang District still keeps the traditional economic development mode with a high consumption and high production, so the emphases of future development should put on improving the improving the efficient use of natural resources and promoting environmental management sustainability. The results show that the indicators system of regional eco-efficiency is a promising method to quantitatively evaluate resources and environmental efficiency and provide an effective decision-making support for local governments.     

The spatial-temporal differentiation of green land use in Beijing–Tianjin–Hebei urban agglomeration

ABSTRACT

As the space carrier of the construction of ecological civilization, land’s green and efficient utilization is an important guarantee for realizing national sustainable development. Based on traditional land evaluation, this paper scientifically defines the green land use, puts land as one of the production factors, and brings energy consumption, environmental pollution, etc. into the input-output system to measure the green land utilization efficiency of the urban construction land of Beijing-Tianjin-Hebei Urban Agglomeration from 2006 to 2016. The study shows that the overall efficiency variation of the urban agglomeration is related with the land and environment policies. Efficiency of 2016 is higher than that of 2006, and energy and environment are the principal factors affecting the green land use. The efficiency of each city is positively correlated with its economic development, negatively correlated with the construction land expansion. Efficiency gaps in different cities are expanding. There is positive correlation with overall weak space between cities, and the partial spatial agglomeration phenomenon appears. Therefore, the green land use efficiency could be improved by improving land utilization efficiency, coordinating economic growth of construction land utilization with environmental protection and taking feasible ways to transregional renovation of the stock ecological land utilization, etc.     

Technological Progress,Structural Change and China’s Energy Efficiency

Abstract

China has witnessed rapid economic development since 1978, and during the time, energy production and consumption developed at a tremendous speed as well. Energy efficiency which can be measured by energy consumption per unit of GDP, however, experienced continuous decrease. Theoretically, the change of energy efficiency can be attributed to industry structural change and technological change. In order to explain the transformation of Chinese energy efficiency, we adopt logarithmic mean Divisia index techniques to decompose changes in energy intensity in the period of 1994–2005. We find that technological change is the dominant contributor in the decline of energy intensity, but the contribution has declined since 2001. The change in industry structure has decreased the energy intensity before 1998, but raised the intensity after 1998. Decomposed technological effects for all sectors indicate that technological progresses in high energy consuming industries such as raw chemical materials and chemical products, smelting and pressing of ferrous metals, manufacture of non-metallic mineral products and household contribute are the principal drivers of China’s declining energy intensity.     

Trade and the environment: An application of the WIOD database

The new WIOD database allows for improved empirical analysis on a wide range of important environmental research questions.In this paper we demonstrate the scientific power of the WIOD database and analyze very urgent policy questions on the impacts of international trade and structural change on the environment.We apply recent econometric approaches to show the impact of international trade on the environment via its different channels as for instance to increase welfare and potentially affect environmental regulation as well as countries’sector.This approach has become known as the econometric structural decomposition method.In addition to these guidelines by the literature,an econometric panel data approach is offered to shed some light on the impact of structural change and international trade on environmental pressure,where we especially address and solve several endogeneity issues that add further complexity to the analysis.     

Rebound effect and its decomposition – an analysis based on energy types in China

Rebound effect derived from energy efficiency improvement has been widely invested. However, most of studies focus on the rebound effect of the energy composite level and neither distinguish nor compare different energy types. We compare the differences in energy saving and energy rebound between primary and secondary energy sources, and further decompose the rebound effect into production rebound part and final demand component. To do so, we add a module for rebound into a comparative state China-CGE model. We design and test two simulation scenarios using the model. In Scenario 1, all production sectors’ energy efficiency of using primary energy increases by 5%. In Scenario 2, all production sectors’ energy efficiency of using secondary energy increases by 5%. The results show that Scenario 2 leads to more GDP growth and more energy saving. Our scenarios show rebound effects range between 9.6% and 27.9%, and in general are higher when energy efficiency of using primary energy sources is improved. Our decomposition analysis shows that improving energy efficiency in production sectors would stimulates energy use of final demand. Indeed, the consumption side has significant contribution to rebound in secondary energy use, especially in crude oil and gas. This study reveals that improving efficiency of using secondary energy is better than improving that of primary energy, both in terms of economic impact and energy rebound. And complementary policies that prevent energy services prices from falling too much can be adopted to reduce rebound. Controlling residential energy use could also be effective in reducing rebound, this has particular implication to economies in which residential energy consumption are far from saturation.     

Energy analysis of algae-to-biofuel production chains integrated with a combined heat and power plant

ABSTRACT

This study examines the energy and mass balances of algae cultivation and different post-processing pathways. Flue gases and excess heat from a combined heat and power (CHP) plant are used in algae cultivation, with nutrients from municipal wastewater. In the studied pathways, algae are cultivated in open ponds and photobioreactors with or without artificial lighting. Algal mass is used for methane, biodiesel or ethanol production, or it is combusted in a boiler. Results show that in most process pathways energy output exceeds the energy consumption in processing, and the energy returns are approximately twice as large as the electricity input. A large fraction of input energy is low-temperature heat, while the products have a higher value. Energy outputs from different pathways are similar, but heat and electricity consumption in processing vary significantly. Supercritical water gasification pathway is identified as a possible future option, whereas lipid extraction pathways are suggested to be the most likely candidates for industrial scale operations.     

China’s Export Expansion,Export Structure and Energy Consumption

Abstract

Since the reform and opening up, China’s export trade has maintained a rapid growth; meanwhile, China’s energy consumption has been increasing sharply. “High export and high energy consumption” has become the feature of China’s trade and economic development. In this paper, based on the input–output analysis approach, the authors have conducted an empirical study on the export trade and energy consumption of 21 trade industrial sectors. The results show that, China is a big net exporter of embodied energy. Assuming that the export growth rate of embodied energy maintains to be about 23.6%, the average annual growth rate of the past 32 years, and based on the input–output data of 2005, by 2030 China’s net export of embodied energy would be over eight times more than the aggregate energy production, which is obviously infeasible. As a country of very low per capita energy, China must change its export pattern, encourage or restrain the export of different industrial sectors according to their energy consumption intensity, and promote structural change of energy– efficient exported products, so as to achieve the sustainable development. Accordingly, the authors put forward some suggestions.     

NEWS

Abstract

Co-integration theory has been employed in this paper and Granger causes are found between urbanization rate and GDP, between capital stock and GDP. Scenario analysis of GDP is performed using the GDP model established in the paper. The energy consumptions in Germany, Japan and other developed countries are analyzed and compared with the energy consumption in China. Environmental friendly scenario of energy demand and CO₂ emissions for sustainable China has been formed based on the results of comparison. Under environmental friendly scenario, the primary energy consumption will be 4.31 billion ton coal equivalence (tce) and CO₂ emissions will be 1.854 billion t-c in 2050; energy per capital will be 3.06 tce that is 1.8 times of energy consumed in 2005 in China and 51% of consumed energy per capital in Japan in 2003. In 2050, the energy requirement of unit GDP will be 20% lower than that of Germany in 2003, but will be still 37% higher than that in Japan in 2003. It is certain that to fulfill the environmental friendly Scenario of energy demand and CO₂ emissions is a difficult task and it needs long term efforts of the whole society, not only in production sectors but also in service and household sectors.     

Industrial energy efficiency potentials: an assessment of three different robot concepts

The rise in energy consumption and the associated costs instigate financial concerns among industrial energy consumers. For industrial processes addressing heating and cooling as well as material transformation, a wide range of energy efficiency measures have been developed and successfully implemented. In contrast to that, most robot-based operations such as pick-and-place motions or assembly tasks still use inefficient standard concepts causing high-energy consumption and high-energy costs. Thanks to a rather low payload-to-weight ratio of new robot designs, such as parallel kinematic or hybrid robot manipulators, a high potential for energy savings is expected. This article identifies potentials for energy saving concerning industrial consumers by assessing three different robot concepts. Based on a literature review, two existing designs for robots – the conventional serial robot and the parallel kinematic robot are analysed and compared with respect to the energy utilised during a typical item placement task. Afterwards, the concept of PARAGRIP, a hybrid of the two presented robot designs is introduced and examined based on simulation regarding its energy consumption. The final results demonstrate significantly different energy consumptions between the robot concepts, identifying potential savings of about 40% in a selected industrial application scenario.     

Cleaner production solution selection for paper making – a case study of Latif paper products Co. Iran

Abstract

The objective of this research is to design an approach for selecting appropriate solutions to efficiently and productively reduce environmental pollution and water, energy and raw material consumption in a recycled paper manufacturing facility, the paper mill in Latif, Iran. To reach this goal, we develop a decision-making model using the Analytic Hierarchy Process (AHP). The proposed model provides a framework for cleaner production implementation specific to the paper industry. Pairwise comparisons of the results of designed questionnaires resulted in the hierarchy model being divided into five major groups: production modification; process change; preventive maintenance; renewal; and manpower resources.These five groups include 31 sub-criteria and seven alternatives. The results showed that process change yields the highest priority among the main criteria and that industrial automation and its technology level gives the highest priority among sub-criteria. Regarding the alternatives, reduction of environmental pollution is the most important solution for cleaner production in the industry. Also, product modification is the most sensitive criterion affecting the alternatives priority.     

A holistic approach to achieving energy efficiency for interoperable machining systems

In the twenty-first century, the continuous demand in energy resource has put sustainability on the agenda of many businesses. This is particularly true for the manufacturing industry, where a large amount of energy is consumed to sustain daily operations. This paper studies energy-efficient computer numerical control machining systems. To achieve overall energy efficiency in machining systems, several activities are involved as in the proposed research framework of a global energy-efficient machining system (GEMS). These activities are described as modules, i.e. energy monitoring, energy analysis and optimisation, energy-based optimal control and energy-enriched database. In a GEMS, one critical issue is data interoperability. Seamless data sharing enables collaboration for improving energy efficiency. Using the EXPRESS language, energy data models are proposed for each module in the GEMS, and integrated with the existing STEP-NC (STandard for Exchange of Produce-compliant Numerical Control) standards. Two case studies are presented to demonstrate how the proposed data models may be used. One study updates an existing production file to include general energy information for auditing or reviewing purposes; the other study maintains machine tool energy profiles in a database. Many other energy-efficient activities, e.g. online energy optimisation, can be realised with the proposed data models. The present study proved that interoperable energy information can enhance the energy-efficient performance of a machining system.     

Environmental management of pesticidal POPs in China: past, present and future

China, the largest developing country in the world, has been undergoing rapid economic growth in the past two decades. Synchronously, large quantities of persistent organic chlorinated pesticides have been used in agriculture and non-agriculture areas. Accompanying with incomplete management framework, the improper use and disposal of pesticides have caused serious pollution problems. In this study, we discussed: (1) ten persistent organochlorine pesticides in terms of historical production, consumption and number of manufacturers, import and export; (2) the current management framework of pesticidal persistent organic pollutants (POPs) with respect to legal system and government administrative system; (3) the existing problems in the management of pesticidal POPs; and proposed recommendations for countermeasures. Based on the available information, it can be concluded that records on the historical production and consumption quantities of pesticidal POPs are incomplete which makes a difficulty in the management. Although China has come a long way in developing a modern legal system, the current system is still considered weak and inefficient; and many challenges are ahead. The government administrative system has also been reformed and improved, but over-lapping jurisdictions still exist and are ineffective in managing pesticidal POPs program. To address these existing problems in pesticidal POPs management, it was suggested that more investigations should be conducted to collect information on pollution sources of pesticidal POPs, to evaluate their environmental risks, to identify new alternative chemicals and to complete management framework of pesticidal POPs in China. Furthermore, the public should be encouraged to participate in managing hazardous pesticidal POPs in China, and international cooperation and communication should be established and strengthened imperatively as well.     

Greenwashing Consumption: The Didactic Framing of ExxonMobil's Energy Solutions

Corporate advertising campaigns increasingly use environmental frames to promote their products and processes, many of which are neither sustainable nor environmentally friendly. This study examines ExxonMobil's recent efforts at green advertising, focusing specifically on their widely aired “Energy Solutions” television advertisements. We argue that ExxonMobil's use of a didactic, greenwashed frame stifles criticism and discourages examination of ideologies of consumption by exploiting the ethos of the scientist and highlighting technological solutions to problems that are deeply tied to a culture of consumerism. The definition of green energy is controlled by those with the power to generate persuasive public messages about the sources and production of energy. Counterframes, however, can be employed to turn a questioning eye upon the solutions advanced by ExxonMobil. We issue a call for green frames that help citizens and consumers critically examine the ecological integrity of all means of energy production, and that call attention to the ways in which the greenwashing of research and development initiatives can dissuade necessary action, including reduction of US energy consumption.     

Research on Energy Consumption Evaluation Combined with Endogenous Pollutants of China Based on Entropy-Topsis

Abstract

The traditional evaluation of energy consumption mostly introduces pollutants as a negative economic output into evaluating model, ignoring the configuration relationship among the energy input, pollutants as well as economic output. This paper considers the overall process of energy consumption and constructs an evaluation indication system of energy consumption level combined with endogenous pollutants based on entropytopsis method, then makes empirical research. The results show that China’s energy consumption level presents a fluctuant rise in the premise of emission. Energy consumption level depends on the relationship among energy input, pollutants and economic output. The raise of energy consumption level should not increase economic output and reduce pollutant emission at the expense of environment. Finally, the whole paper puts forward the countermeasures to improve the overall level of energy consumption.     

Energy intensity trends and scenarios for China��s industrial sectors: a regional case study

Due to its rapid industrialization and urbanization, China faces the daunting challenge of sharply growing energy and resource consumption. It is now indispensable for the nation to alter its course of development into more sustainable paths in terms of energy and resource efficiency. In this paper, we discuss the energy intensity of the industrial sectors of the Yangtze River Delta, consisting of Shanghai City and the neighboring province of Jiangsu—the fastest economically developing region of the country—and argue possible strategies for energy efficient industrial activities there. We first examine the historical trends of energy intensity associated with industrial sectors and study the factors affecting the evolution of these trends by applying decomposition analysis. We then argue that if “business as usual” (BAU) development patterns are continued, energy intensity level in both regions may surpass China’s policy targets in 2010, and GDP growth as well as energy consumption will exceed possible pathways under current policy targets by 2020. Thus, appropriate measures are urgently needed to lower energy intensity and consumption. Based upon these analyses as well as the Chinese government’s policy orientation, we propose two options as alternative scenarios for improving practices in energy-intensive industries, particularly targeting the cement and steel production sectors. These options are: (1) diffusion of highly energy efficient technologies into these industries, and (2) promotion of a circular economy and industrial symbiosis. We highlight that these options can potentially lead to energy savings and reductions in resource consumption associated with industrial activities and can serve as a regional model for more sustainable industrial activities in China.     

Energy consumption analysis of ABS plastic parts injected in a hybrid injection moulding machine

The energy analysis of injection moulding processes is influenced by complex interactions amongst the moulded part, its material, the injection machine, the process parameters and the environmental conditions. The availability of energy usage analyses that comprehend information on specific materials and machine kind is limited. This paper reports a study that estimates and analyses the power usage profile (PUP), the specific energy consumption (SEC), and the energy distribution at an operation level of two different injected parts made of acrylonitrile-butadiene-styrene and produced in a hybrid injection moulding machine. The methodology followed by the authors incorporates an experiment carried out in an industrial facility. A large sample size, and data-acquisition and data post-processing processes to obtain an accurate PUP and SEC are used. A breakdown of the energy consumed by the injection moulding process of the parts studied at an operation level using Sankey diagrams is discussed. The study results are used to identify strategies to reduce the energy consumed by the processes. The methodology employed, and the strategies reported could be used with other plastic parts regardless of the material and machine used. The results reported are new experimental data useful input for theoretical models.     

An analytical investigation on energy efficiency of high-speed dry-cutting CNC hobbing machines

Abstract

Energy efficiency analysis has been recognised as an effective measure for the energy prediction, energy assessment and energy benchmarking in the machining system. However, study on energy efficiency of CNC hobbing machines, especially high-speed, dry-cutting CNC hobbing machines (HSDC-CHM), is still scarce. The energy consumption by HSDC-CHM is generally considered larger, and energy efficiency lower, than wet-cutting CNC hobbing machines (WC-CHM). Therefore, this paper summarises the investigation of energy efficiency of HSDC-CHM and establishes energy efficiency models of CNC hobbing machines. Energy efficiency of HSDC-CHM and WC-CHM are compared and analysed based on energy efficiency models established. Through the theory analysis, results show that, in the production line, although HSDC-CHM possess larger transient energy consumption, its energy efficiency is higher than energy efficiency of WC-CHM. Moreover, it is difficult to obtain quantitative energy efficiency of two types of hobbing machines due to massive relevant hard-to-acquire parameters using energy efficiency models; for this reason, experiments are performed to compare and analyse energy efficiency of HSDC-CHM and WC-CHM. The experiments results indicate that energy efficiency of HSDC-CHM is excellent and far higher than WC-CHM. The study results have a positive significance for the development and application of HSDC-CHM.     

Income Growth,Urbanization, Changing Life Style and Energy Requirements in China

Abstract

This paper aims to estimate the effects of changing life style and consumption demands driven by income growth and urbanization on increase of energy requirements in China, and estimate the impacts of improvement in household consumption on mitigating energy requirements towards 2020, based on input-output analysis and scenarios simulation approach. The result shows that energy requirement per capita has increased by 159% for urban residents and 147% for rural residents from 1995 to 2004. Growth in household consumption driven by income growth and urbanization may induce a successive increase in energy requirements in future. Per capita energy requirements of urban residents will increase by 240% during 2002–2015 and 330% during 2002–2020. Urbanization might lead to 0.75 billion ton of increment of energy requirements in 2020. About 45%–48% of total energy requirements in China might be a consequence of residents’ life styles and the economic activities to support consumption demands in 2020. Under low-carbon life style scenario, per capita energy requirements of urban residents may decline to 97% in 2015 and 92% in 2020 in contrast with baseline scenario. That implies that China needs to pay a great attention to developing green low-carbon life style in order to realize mitigation target towards 2020.