Using Overall Equipment Effectiveness for Manufacturing System Design

Different metrics for measuring and analyzing the productivity of manufacturing systems have been studied for several decades. The traditional metrics for measuring productivity were throughput and utilization rate, which only measure part of the performance of manufacturing equipment. But, they were not very helpful for “identifying the problems and underlying improvements needed to increase productivity” [1]. During the last years, several societal elements have raised the interest in analyze the phenomena underlying the identification of productive performance parameters as: capacity, production throughput, utilization, saturation, availability, quality, etc. This rising interest has highlighted the need for more rigorously defined and acknowledged productivity metrics that allow to take into account a set of synthetic but important factors (availability, performance and quality) [1]. Most relevant causes identified in literature are: The growing attention devoted by the management to cost reduction approaches [2] [3]; The interest connected to successful eastern productions approaches, like Total Productive Maintenance [4], World Class Manufacturing [5] or Lean production [6]; The importance to go beyond the limits of traditional business management control system [7]; For this reasons, a variety of new performance concepts have been developed. The total productive maintenance (TPM) concept, launched by Seiichi Nakajima [4] in the 1980s, has provided probably the most acknowledged and widespread quantitative metric for the measure of the productivity of any production equipment in a factory: the Overall Equipment Effectiveness (OEE). OEE is an appropriate measure for manufacturing organizations and it has being used broadly in manufacturing industry, typically to monitor and control the performance (time losses) of an equipment/work station within a production system [8]. The OEE allows to quantify and to assign all the time losses, that affect an equipment whilst the production, to three standard categories. Being standard and widely acknowledged, OEE has constituted a powerful tool for production systems performance benchmarking and characterization, as also the starting point for several analysis techniques, continuous improvement and research [9] [10]. Despite this widespread and relevance, the use of OEE presents limitations. As a matter of fact, OEE focus is on the single equipment, yet the performance of a single equipment in a production system is generally influenced by the performance of other systems to which it is interconnected. The time losses propagation from a station to another may widely affect the performance of a single equipment. Since OEE measures the performance of the equipment within the specific system, a low value of OEE for a given equipment can depend either on little performance of the equipment itself and/or time losses propagation due to other interconnected equipments of the system. This issue has been widely investigated in literature through the introduction of a new metric: the Overall Equipment Effectiveness (OTE), that considers the whole production system as a whole. OTE embraces the performance losses of a production system both due to the equipments and their interactions. Process Designers need usually to identify the number of each equipments necessary to realize each activity of the production process, considering the interaction and consequent time losses a priori. Hence, for a proper design of the system, we believe that the OEE provides designer with better information on each equipment than OTE. In this chapter we will show how OEE can be used to carry out a correct equipments sizing and an effective production system design, taking into account both equipment time losses and their propagation throughout the whole production system. In the first paragraph we will show the approach that a process designer should face when designing a new production system starting from scratch. In the second paragraph we will investigate the typical time-losses that affect a production system, although are independent from the production system itself. In the third part we will define all the internal time losses that need to be considered when assessing the OEE, along with the description of a set of critical factors related to OEE assessment, such as buffer-sizing and choice of the plant layout. In the fourth paragraph we will show and quantify how time losses of a single equipment affects the whole system and vice-versa. Finally, we will show through the simulation some real cases in which a process design have been fully completed, considering both equipment and time losses propagation

Improving Energy Efficiency in Manufacturing Systems — Literature Review and Analysis of the Impact on the Energy Network of Consolidated Practices and Upcoming Opportunities

Global energy context has become more and more complex in the last decades: raising prices of depleting fossil fuels, together with economic crisis and new international environmental and energy policies, are forcing companies (and manufacturing industry in particular, which is responsible for 90% of industry energy consumptions, in turn making up the 51% of global energy usage, as listed on EIA, the Energy International Agency, website, last accessed on the 5th of October 2014) to cut energy wastes and inefficiencies, and to control their consumptions. Besides the existing analysis of the above mentioned regulatory and economic concerns, Energy Efficiency criticality for manufacturing systems has recently been investigated and proved also by the analysis of its connection with Productivity Efficiency [1-4], which resulted to be strong and mutual, and of the numerous non-energy benefits achieved while performing energy efficiency measures [5], such as the improvement of corporate image and the environmental impact reduction. Over most recent years, Energy Efficiency has therefore become a critical factor for industrial plants’ competitiveness, and is now definitely considered as a key driver to economic development and sustainability. But, despite it all, it is often still difficult for many companies to understand its effectiveness, in good part because of the difficulties met in focusing its technical and economic benefits, as Laitner [6] highlights: “Energy Efficiency has been an invisible resource. Unlike a new power plant or a new oil well, we do not see energy efficiency at work. (...) energy efficiency may be thought of as the cost-effective investments in the energy we do not use either to produce a certain amount of goods and services within the economy.” As a matter of fact, Energy Efficiency still represents a challenging goal for most companies. As above mentioned, numerous problems are yet to overcome in quantifying its benefits and evaluating the cost-effectiveness of related investments, and most of all the huge variety, complexity and changeability of fields, technologies and methodologies involved in its improvement in production systems are responsible for the slowing down of their resolution and of the spread of Energy Efficiency measures and culture. In fact, in order to individuate and prioritize suitable improvement interventions and Energy Efficiency opportunities, and to design and customize the Energy Management System or the Monitoring and Control System according to a particular company’s needs, a deep and complete knowledge of many different subjects and disciplines (ranging from physics and thermodynamics to economy and project management) is needed, besides a good ability and practical sensibility to direct one’s efforts in the right way. Considering that Energy Efficiency isn’t obviously the core business of manufacturing industry, such effort might sometimes be very laborious, and in recent years many companies have decided to demand Energy Management activities to specialized external companies, the so-called Energy Service Companies (ESCos). ESCos generally own the know-how required to individuate Energy Efficiency measures and are also able to fund Energy Efficiency investments (see [7] for a specific literature review); what they usually do not own is a deep understanding of the company’s dynamics, situations and needs, as well as the capability to draw a long-term development path towards the achievement of a diffused Energy Efficiency culture within the company, which shall be consistent with the company’s vision and policies and is essential in order to consolidate and continuously upgrade improvements in such sector. It is then crucial for companies to have at least a general consciousness of all intervention areas and of all possible improvements, both managerial (and/or behavioural) and technological, that could be pursued and achieved, in order to be able to lead their own way towards their sustainable development, and also to capitalize ESCOs’ assistance and services. In order to overcome part of these difficulties, and in particular to make it easier for companies to address their efforts and catch best efficiency opportunities, a logical and systemic approach is necessary: it would help not to overlook any possible area of improvement, to easily classify and understand those areas, but also to identify the most suitable and cost-effective, and eventually to prioritize them. In the light of this, some studies have already been conducted in order to find out methods and tools to assess the current level of maturity of a company in the Energy Management field [8], and to help individuating a possible development path. However, although they point out some possible development scenarios, they do not provide a complete and organic categorization of all possible areas of intervention, so as to make it easier for practitioners to address their efforts into the right way. In this chapter, a new conceptual scheme to organize and classify Energy Efficiency measures is defined, leading from the definition of Energy Cost per Product Unit and further breaking it up in order to identify and define all possible areas of intervention, providing for each of them a brief overview of possible measures and opportunities and a specific literature review. All scientific papers, books and technical papers considered for the literature review of each area (chosen on the basis of a wide literature research and on authors’ on-field experience) are recalled and systematized in Table 1, so that the reader is guided through their examination and rapidly addressed to their consultation. In addition, a qualitative evaluation of the impact of some possible Energy Efficiency measures from each area on the energy network is given, in order to give both practitioners and researchers a first input to further focus on this additional feasibility evaluation criteria for Energy Efficiency measures, which enables to evaluate them on a national or international level rather than considering the benefits or concerns belonging to a single company

A proposal for energy servicesʼ classification including a product service systems perspective

Western manufacturing companies have lately started to rethink their approach to sustainability, mainly because of three different issues arising in the international context: the economic and financial crisis that has been slowing down the international marketsʼ growth, the necessity to increase competitiveness and the growing awareness of environmental and energy problems. This process has eventually led to the spread of servitization strategies causing the transformation of several equipment/components manufacturers into service providers, as well as to the creation of the concept of Product-Service Systems (PSS). Furthermore, a more focused attention to energy efficiency has arisen, with the dual objective of both containing costs and meeting international regulations. The intersection of these two development paths is the constant increase in the supply of energy services, which can be marketed together with devices, machines or energy vectors, creating a peculiar form of PSS. In the present work, a new classification is proposed to map different types of energy services, based on existing categorizations of PSS and enriching them with new parameters which are typical of energy services literature, such as the level of risks sharing. The main objective of this work is to highlight the tight connection between the provision of energy services and the concepts of PSS and sustainability, in order to provide a new general classification for energy services, discussed separately and fragmentary so far in literature

new efficiency opportunities arising from intelligent real time control tools applications the case of compressed air systems energy efficiency in production and use

Abstract Most of the production facilities in Europe make use of compressed air to drive equipment for manufacturing and Compressed Air Systems (CAS) account for about 10% of the total electrical energy consumption of European industries. Therefore, reducing CAS energy consumption is a crucial task to meet the European goals of improving energy efficiency and reducing environmental impact of the industrial sector. This work is part of a wider research activity aimed at developing a strategy to optimize the energy use in CAS. In particular, this paper shows the importance of monitoring energy consumption and control energy use in compressed air generation, to enable energy saving practices, enhance the outcomes of energy management projects, and to guide industries in energy management. We propose a novel procedure in which measured data are compared to a baseline obtained through mathematical modelling (i.e. regression functions) to enable faults detection and energy accounting, through the use of control charts (i.e. variations' control and the Cumulative Sums). The effectiveness of the proposed methodology is demonstrated in a case study, namely the compressed air system of a pharmaceutical manufacturing plant

assessing and improving compressed air systems energy efficiency in production and use findings from an explorative study in large and energy intensive industrial firms

Compressed Air Systems (CAS) are one of the most common and energy intensive utilities in industry, representing up to 10% of the industrial energy needs. Nevertheless, benchmarks currently available are usually based on nominal data and referred to the quality of the design, while there are still no available benchmarks based on measured industrial data, taking into consideration actual operating conditions, and referred to compressed air production and, most of all, use. In accordance with the Italian transposition of the European Directive 2012/27/EU (i.e. Legislative Decree 102/2014) large and energy-intensive enterprises have been asked to perform mandatory energy audits in 2015. In this context, a data collection focused on CAS has been carried out by means of a semi-structured questionnaire in the form of a spreadsheet. First data analyses performed and relative findings are here illustrated, together with the next steps for the creation of reliable sectorial and cross-sectorial benchmarks

Regulatory Response to Self-production of Energy: A Risk for the Development of Renewable Sources and Combined Heat and Power

The high price for electrical energy increasingly leads companies to engage in self-production, so as to reduce costs, increase their own energy efficiency, and achieve market competitiveness. In general such self-production solutions have positive environmental impacts, since they involve exploitation of renewable sources and high-yield cogeneration plants, as well as avoiding inefficiencies due to network losses. However, the resulting reduction in the network exchange of electrical energy does not lead to proportional reductions in the network costs, and finding adequate coverage for these remains a necessity. Given this context, the role of the regulator becomes fundamental. The regulator must implement strategies for purposes of meeting national needs in regards to costs, but without excessively penalizing the companies and their international competitiveness, and without holding back development of environmentally favourable and sustainable solutions. The current article analyzes the possible regulatory interventions, their technical and organizational difficulties, and the impacts of these strategies in the national context. Keywords: energy self-production; renewable sources; CHP; network costs; general system fees; regulatory interventions JEL Classifications: L5, Q2, Q

Industrial Energy Management and Sustainability

Increasing the sustainability of industrial activities is a top priority for national and supranational governmental institutions [...