Computational energy estimation tools for machining operations during preliminary design

The aim of this paper is to develop computational machining energy estimation tools during the early design stage of product development. In the preliminary or embodiment design, a product's shape and materials are determined. At this stage, it is crucial for a designer to be able to compare alternative designs and materials based on many different criteria, such as cost, functionality, energy, etc. Automated tools for estimating energy consumption that could later be used to integrate with CAD/CAM systems are in demand. This study presents computational tools for estimating the energy consumption of machining operations during the early design phase. The computational tools utilize a preliminary computer representation of a product (CAD model), its material and candidate machining operations to automatically analyse and estimate a range of energy consumption during machining operations. Detailed steps for computing turning and milling energy consumption are presented. Case studies of both parts and assemblies were conducted to test the validity of the tools and to evaluate the performance of the tools. Environmental impacts such as carbon weight will also be estimated. The computation tools will assist users with little knowledge about energy computations to estimate energy consumption during the design stage. Such energy estimation can be used to redesign parts and assemblies, leading to the development of products with reduced machining energy. The computation tools are part of a larger research on estimating energy consumption throughout a product's life cycle.     

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.     

An integrated approach for improving energy efficiency of manufacturing process chains

The rising energy prices and increasingly imposing regulations have drawn attention for improving the energy efficiency of manufacturing processes. Over the past decade, different approaches have been developed to target from individual unit processes to entire manufacturing systems. However, each model or approach has limitations in terms of the efficiency improvement. Thus, an integrated approach is proposed to overcome these limitations combining unit process energy consumption models with production system simulation. The outcome potentially leads to a more energy-efficient production and process planning, which considers the dynamics of individual processes as well as the entire system. Two case studies are presented to demonstrate the approach and its benefits.     

The impact of energy awareness on energy efficiency

The increasing levels of global warming, depleting sources of fossil fuels and increasing energy costs are all having a large detrimental effect on today's society. Many efforts are being made to try and increase energy efficiency all over the world. One of the major problems is unnecessary and excessive energy utilisation. This problem has been identified by Loughborough University and they are making efforts to try and reduce energy wastage. One of their strategies, used up until recently, involved increasing energy awareness within students in halls of residence by means of a reward system called the Residential Halls Energy Efficiency League (Imago Services, Loughborough Students Union, Estates Services 2006). This scheme managed to reduce energy consumption by up to 10%, saving an estimated £9000 in only 52 days. Can those results be improved by targeting students more specifically? How much energy can be saved by increasing energy awareness?     

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.     

市场分割对能源效率的影响研究

探究能源效率的影响因素并有针对性地提出对策建议是实现"十三五"节能目标的前提条件。本文利用1986—2014年的省际面板数据,基于随机前沿分析和反事实计量方法,重点考察了市场分割对能源效率的影响。结果显示:1市场分割显著地抑制了能源效率的提升;2在考虑市场分割的情形下,能源效率从1986年的0.413提升到了2014年的0.739,年均增速为2.1%,但能源效率依然有较大的改善空间,如果能够消除市场分割的不利影响,能源效率平均每年将会获得1.5%的额外提升;3在样本考察期内,由于市场分割导致的直接能源损失平均每年约为1 200万t标准煤,若考虑市场分割产生的其他间接影响及其动态效应,这一数字估计值会更高;4产权结构改革、对外开放、产业结构升级以及节能法的颁布促进了能源效率的改善,而金融发展规模、政府干预以及以煤炭为主的能源消费结构不利于能源效率的提升。以上研究结论蕴含的政策含义是:为提高能源效率,需要加强市场一体化建设,打破省际壁垒,整合国内市场。鉴于市场分割可能是一些地方政府的占优策略,因此,需要中央政府来进行推动。一方面,中央政府可以通过加强监管和查处力度直接惩罚市场分割行为,另一方面,中央政府还可以通过转移支付的方式鼓励落后地区积极主动融入国内整体市场。当然,提高能源效率,也需要诸如推进产权结构改革,提高对外开放水平,优化产业结构与能源消费结构,改善金融发展效率,减少政府干预以及完善能源政策法规等其他措施的共同跟进。     

电网发展、清洁电源接入与地区能源效率

鉴于我国已经建成全球规模最大的超高压和特高压电网,彻底弥补了电力跨区配置的电网基础设施短板,并且为清洁电源并入电网和跨区消纳提供了完善的基础设施,不仅克服我国电力负荷中心和能源基地的区域布局不协调,而且有益于缓解日益严峻的能源利用率低下和环境污染问题。本文利用1991—2012年全国29个省市面板数据实证研究了清洁电源并网对地区全要素能源效率的影响。为保证实证结果稳健性分别在线性和非线性实证框架下采用系统广义矩估计(SYS-GMM)和面板平滑转换模型(PSTR)两种方法估计了清洁电源接入高压、超高压和特高压电网的地区全要素能源效率异质性效应。实证结果显示:(1)我国电网基础设施对地区全要素能源效率具有明显的增进效应,特别是超高压电网在促进全要素能源效率提升上表现的最为突出,在特高压骨干网架尚未形成的情况下起到了支柱性作用。(2)高压、超高压、特高压与清洁电源交互项的估计系数始终位于负数区间,反映清洁电源并网的能源效率绩效并不明显,受限于并网规模和机制缺陷,还没有发挥出全要素能源效率提升作用。(3)随着人均GDP的不断提高,各等级电网对地区能源效率的益处越来越明显,并且存在着门槛效应。(4)特高压电网对地区能源效率的积极作用主要表现在东部沿海高收入省份,这些省份作为电力消费负荷中心,大规模接入清洁电源对能源效率改善裨益明显。接下来,需要根据地区的能源禀赋结构选择清洁电源的并网模式,完善的电网基础设施、合理的电源结构还需要配置以高效的清洁电源并网机制才能不断增进地区全要素能源效率。     

A strategic quantitative approach for sustainable energy production from biomass

European legislation has created a growing interest in the field of renewable energy production in several countries, including Italy. The applications of biomass and/or biofuel for energy generation have been assumed to provide a high level of sustainability due to the perception that renewable resources are inherently sustainable. Thus, renewable fuels applied to heating and/or electricity generation are potentially carbon dioxide neutral. However, before accepting this assumption, it is essential to analyse the actual level of sustainability in the whole supply chain (SC). This requirement has been clearly identified by the recently updated European Directives on renewable biofuels for transportation. However, there is little evidence that this concern has been directed at energy production from biomass. Thus, approaches derived from Green SC Management (GSCM) methods could provide an effective tool for evaluating, from a strategic perspective, the sustainability level of a specific biomass SC. This paper examines how biomass SC activities can define the overall environmental sustainability level. The approach was based on environmental indicators and the resultant output could support more effective GSCM strategies (e.g. defining logistics carriers, evaluating new biomass suppliers, etc.) for managing biomass SCs. Moreover, the approach could be applied by competent authorities for a quick evaluation of the sustainability level of biomass energy production installations. The approach has been tested in a real case study based on an installation, located in Southern Italy, which uses liquid biomass for energy production.     

Synergico: a method for systematic integration of energy efficiency into the design process of electr(on)ic equipment

This paper presents an overall design method to better consider the energy consumption of electrical and electronic equipment during the use phase. This aspect is often considered as the most important environmental aspect in active electrical and electronic equipment during its life cycle. The proposed method, called ‘Synergico’, characterises the product energy efficiency according to its modes, its functions and its sub-assemblies. It also articulates three tools: one assessment tool, one improvement tool and one environmental check tool. These tools are integrated along a typical product design process. The method therefore helps designing more energy-efficient products without compromising other performances such as ergonomics, functional performances, security, recyclability or costs. The three tools and the overall method are presented. A case study illustrates the way it works and is discussed.     

Analysis of availability and accessibility of hydrogen production: An approach to a sustainable energy system using methane hydrate resources

It is considered that use of hydrogen as an energy source may contribute to environmental improvement and provide an alternative energy system. Moreover, it is anticipated that hydrogen will be in great demand in the near future for use in such vehicles as fuel cell-based cars. Research and development of a number of advanced methods of hydrogen production (OTEC, water photolysis using a semiconductor, a municipal waste gasification—smelting system, etc.) is currently under way.A comparison of different hydrogen-rich fuels in this paper shows that methane is advantageous for hydrogen production from the viewpoint of energy efficiency as measured by thermodynamic analysis. This paper therefore proposes combining existing technology for hydrogen production with an unconventional methane source in order to facilitate the realization of a hydrogen energy system: i.e., this paper proposes combining the process of steam reforming, which is commercialized worldwide, with use of untouched natural gas hydrate (NGH) resources. Gas hydrate deposits, which are distributed worldwide, hold great amounts of methane gas and have hardly been touched. This paper presents the economic parameters of NGH development and discusses the concept of devising useful applications of NGHs, with consideration given to (1) independence from current fossil fuels; (2) energy transport using the hydrate system; (3) CO₂ sequestration — replacement of methane hydrate with CO₂ hydrate in the submarine layer and (4) improvement of current steam reforming of methane by CO₂ reuse and zeolite application. This paper thus proposes a new solution that will make a key contribution to the systematic development of a new sustainable energy structure.Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

长江中游城市群能源效率评价研究

提高能源效率、促进低碳经济转型是当前长江中游城市群区域协同发展和新型城镇化建设的重点和难点。基于共同前沿(Meta-frontier)理论,利用数据包络分析方法构建非参数前沿,并将SO2排放量这一非期望产出纳入DEA模型中,比较分析了2005—2014年长江中游城市群全要素能源效率的区域差异,采用"技术缺口比率"衡量长江中游城市群三大区域之间能源利用的技术差距,并在此基础上研究了能源非效率的分解以及对真实的能源强度和潜在的能源强度进行了相关分析。研究结果表明:1当前长江中游城市群全要素能源效率整体水平偏低,但地区差异并不显著。2三大区域之间的能源技术差距不是很大。3技术缺口和管理等因素对不同区域能源非效率的作用不同。4真实的能源强度和潜在的能源强度都具有一定下降的趋势,而且两者之间的差距逐渐缩小。最后根据分析结果得出一些结论和启示,如制定区域节能战略时坚持"求同存异"的原则,加快技术进步,积极进行能源技术创新,不断提高管理水平等。同时,政府应加大对长江中游城市群的政策倾斜力度,这样才能充分挖掘长江中游城市群的节能减排潜力,这对提升中国区域能源效率的整体水平以及促进绿色经济转型具有重大意义。     

A framework to minimise total energy consumption and total tardiness on a single machine

A great amount of energy is wasted in industry by machines that remain idle due to underutilisation. A way to avoid wasting energy and thus reducing the carbon print of an industrial plant is to consider minimisation of energy consumption objective while making scheduling decisions. To minimise energy consumption, the decision maker has to decide the timing and length of turn off/turn on operation (a setup) and also provide a sequence of jobs that minimises the scheduling objective, assuming that all jobs are not available at the same time. In this paper, a framework to solve a multiobjective optimisation problem that minimises total energy consumption and total tardiness is proposed. Since total tardiness problem with release dates is an NP‐hard problem, a new greedy randomised multiobjective adaptive search metaheuristic is utilised to obtain an approximate pareto front (i.e. an approximate set of non‐dominated solutions). Analytical Hierarchy Process is utilised to determine the ‘best’ alternative among the solutions on the pareto front. The proposed framework is illustrated in a case study. It is shown that a wide variety of dispersed solutions can be obtained via the proposed framework, and as total tardiness decreases, total energy consumption increases.     

Way for sustainable development of energy in China

The report of Chinese Communist Party's 18th National Congress clearly stated that the construction of ecological civilization needs to join hands with the overall layout of the construction of socialism with Chinese characteristics,and the greatest obstacle to achieving ecological civilization is the energy structure in China.Currently,the third industrial revolution—marked by green technology and cloud computing technology—is happening,and it will have a huge impact on future energy development.The fundamental way to solve the problem of energy resource constraints is developing the renewable energy,and the fundamental approach for renewable energy is developing distributed energy and services.The important factors to achieving China's energy production and consumption revolution are accelerating the construction of distributed energy system and overall energy structure adjustment in China.     

基于能源类型的中国反弹效应测算及其分解

能源问题是实现可持续发展的重大战略问题。能效改进所引起的能耗反弹问题已成为能源经济学领域的一个重要议题。针对已有研究基于复合能源维度探讨反弹效应的不足,本文通过构建一个引入反弹效应测算模块的中国静态CGE模型,研究不同类型能源效率改进的节能效果和反弹差异,并将其在生产侧和消费侧进行分解。在分别提高所有生产部门一次能源使用效率和二次能源使用效率两种情景下,我们发现提高二次能源使用效率对经济的促进作用更大,带来的能源节约也更多。就反弹效应而言,两种情景的反弹效应在9.6%-27.9%范围间,但提高一次能源使用效率带来的反弹效应要普遍大于提高二次能源使用效率带来的反弹。这意味着,能效改进的能源类型选择将关系到政策的实施效果。对反弹效应在生产侧和消费侧的分解则显示,生产侧的能效改进会刺激消费侧能耗增加,而且来自消费侧的能耗增加在二次能源品种的反弹效应中扮演了重要角色,尤其是成品油和燃气。综上,我们认为不论从经济表现还是反弹效应来看,提高二次能源使用效率都是比较理想的能源类型选择,这是以往研究未曾注意到的。同时,由于反弹效应的存在确实降低了能效政策的有效性,因此政府在制定能效政策时可通过对冲能效改进带来的能源服务价格下降来减缓能耗反弹。引导和规范居民的用能观念和用能行为也是减缓反弹效应的一个重要途径,这一点对能源需求远未饱和的发展中国家尤其重要。     

Pre-feasibility study of stand-alone hybrid energy systems for applications in eco-houses

In light of rising cost of fossil fuels and fears of its depletion, coupled with the increase in energy demand and the rise in pollution levels, governments worldwide have had to look at alternative energy resources. Combining renewable energy generation like solar power with superior storage and conversion technology such as hydrogen storage, fuel cells and batteries offers a potential solution for a stand-alone power system. The aim of this paper was to assess the techno-economic feasibility of using a hybrid energy system with hydrogen fuel cell for application in an eco-house that will be built in Sultan Qaboos University, Muscat, Oman. Actual load data for a typical Omani house of a similar size as the eco-house was considered as the stand-alone load with an average energy consumption of 40 kW/day and 5 kW peak power demand. The National Renewable Energy Laboratory's Hybrid Optimisation Model for Electric Renewable software was used as a sizing and optimisation tool for the system. It was found that the total annual electrical energy production is 42,255 kW and the cost of energy for this hybrid system is 0.582 $/kW. During daylight time, when the solar radiation is high, the photovoltaics (PV) panels supplied most of the load requirements. Moreover, during the evening time the fuel cell mainly serves the house with the help of the batteries. The proposed system is capable of providing the required energy to the eco-house during the whole year using only the solar irradiance as the primary source.     

An enhanced sustainable approach for design and manufacturing with an application to fuselages for mono-seat civil sailplanes

Abstract

A number of tools and software systems have been developed in order to reduce the time for the design and manufacturing of industrial products. Nowadays, virtual modelling by Computer Aided Design (CAD) systems and process simulation by the application of Finite Element Method (FEM) software is a standard routine in order to compress product design activities and to achieve the optimal solution before producing any real components. These developments provided not only a reduction in the time to market but a higher complexity of the project and an improved quality of the industrial products. With the aim to further improve the sustainability of this activity, the implementation of a tool that adds automatic operations into the design activity is demonstrated. This software can interact with any CAD and helps designers when the object dimension and shape can be affected by limits and constraints deriving from different features and targets, such as the spatial collocation of the component and the interaction with other limiting items, for examples the material and the manufacturing issues. The concept was developed into the software SFIDA (Sailplane Fuselage Integrated Design Application) that is a first attempt to automatically manage multiple relations and optimise their combination.     

A Graph Theory approach to measure the performance of sustainability enablers in a manufacturing organization

In a manufacturing organization, the term sustainability deals with the impact of production process and products on the environment and society, laying emphasis on preservation of scarce resources. In this article, the study concentrates on developing a Graph Theory model to measure the performance and inter-relationship between the sustainability enablers in an organization, thereby to quantitatively measure the extent to which ‘sustainable manufacturing’ practices are being followed in the organization. The objective of this study was to identify a set of sustainability enablers and attributes that impact a manufacturing organization. Digraphs were developed for the whole system and sub-systems depicting the inter-relationships and dependencies between various enablers and attributes to interpret the performance of the sustainability enablers in the case organization. Using the best case and worst case values, the level of sustainable manufacturing practices of the organization was found by Comprehensive Assessment Index. Based on the best case values, the relative significance of individual sustainability enablers are found and compared with worst case situations. The impacts of individual enablers on the overall sustainability level of the organization were also studied.     

Energy and temperature performance analysis of geothermal (ground source) heat pumps integrated with permeable pavement systems for urban run-off reuse

Geothermal (ground source) heat pumps (GHP) and permeable pavement systems (PPS) have demonstrated their effectiveness in both industry and academic research during recent decades. To meet the rising demand for sustainable, recyclable and energy efficient techniques, research has focused on the combination of techniques to enhance existing or develop new applications.

This paper reports on an experimental programme that combined GHP with PPS for nutrient removal and system energy balancing. Experimental data collected over a 3-year period have provided evidence of highly efficient removal rates of up to 99% for ammonia–nitrate and biochemical oxygen demand; and 96% removal rates were obtained for orthophosphate–phosphorus. This paper also contains energy efficiency ratio (EER) and coefficient of performance (COP) calculations. Cyclic heat removal and heat rejection allowed for stable temperature and pump COP and EER sustainability. The results prove that PPS systems are appropriate for GHP installation, delivering high and stable pollutant removal with EER efficiencies between 1.5 and 5.5.

The combination of GHP with PPS has the potential to provide a new sustainable and eco-friendly practice.     

A methodology for electricity monitoring and targeting (M&T) in an Irish precision engineering SME

Abstract

Energy management in small to medium enterprises (SMEs) remains undeveloped due to competing priorities and a lack of specialist knowledge. However considerable savings can be demonstrated where companies take the time to investigate their energy use. Savings of over 20% can be achieved through changes to operational and behavioural practice. Additional benefits, such as improved production tracking and improved maintenance, can been seen which add to the value in undertaking an energy monitoring and targeting (M&T) plan. The method described involves the application of a series of ‘virtuous’ cycles of engagement and energy savings that can be applied from the highest factory level right down to a specific machine. The analysis of overall energy use from utility bills and the visualisation of typical machine power profiles aid in understanding the drivers of energy consumption and in engaging management in energy efficiency. The monitoring of specific machines in production highlights the significant consumption of electricity during non-productive times. The development of energy performance indicators is described for product variations which can be useful in tendering for business and selecting optimum production pathways. The approach is illustrated with data from a case study of a precision engineering SME based in Limerick, Ireland.