Energy Efficient Policies, Scheduling, and Design for Sustainable Manufacturing Systems

Climate mitigation, more stringent regulations, rising energy costs, and sustainable manufacturing are pushing researchers to focus on energy efficiency, energy flexibility, and implementation of renewable energy sources in manufacturing systems. This thesis aims to analyze the main works proposed regarding these hot topics, and to fill the gaps in the literature. First, a detailed literature review is proposed. Works regarding energy efficiency in different manufacturing levels, in the assembly line, energy saving policies, and the implementation of renewable energy sources are analyzed. Then, trying to fill the gaps in the literature, different topics are analyzed more in depth. In the single machine context, a mathematical model aiming to align the manufacturing power required to a renewable energy supply in order to obtain the maximum profit is developed. The model is applied to a single work center powered by the electric grid and by a photovoltaic system; afterwards, energy storage is also added to the power system. Analyzing the job shop context, switch off policies implementing workload approach and scheduling considering variable speed of the machines and power constraints are proposed. The direct and indirect workloads of the machines are considered to support the switch on/off decisions. A simulation model is developed to test the proposed policies compared to others presented in the literature. Regarding the job shop scheduling, a fixed and variable power constraints are considered, assuming the minimization of the makespan as the objective function. Studying the factory level, a mathematical model to design a flow line considering the possibility of using switch-off policies is developed. The design model for production lines includes a targeted imbalance among the workstations to allow for defined idle time. Finally, the main findings, results, and the future directions and challenges are presented

An energy audit of the Canmore Nordic Centre

The operation of buildings consumes a considerable amount of energy worldwide. Rising energy costs and the desire to reduce greenhouse emissions mean the desire to improve energy efficiency is becoming increasingly strong. Energy audits provide a structured method of analysing energy consumption at a facility in order to understand how energy is being consumed and thereby make intelligent decisions on how to improve energy efficiency and reduce energy consumption. This dissertation provides a review of the practical application of an energy audit to the Canmore Nordic Centre, a cross country ski training and recreation facility located in the province of Alberta, Canada. The audit process is first placed in context through a literature review of building energy trends, the relevance of energy efficiency, energy auditing methods and a number of case studies of energy efficiency measure implemented in similar facilities. A method of auditing the particular facility is developed, the results of the audit presented and the implications of the results to wider sector and other findings discussed. The energy audit identified 38 specific efficiency measures that have the potential to save 3692 GJ of energy annually, saving $31,400 in energy costs and 325 tonnes CO2e per year. The facility was found to be relatively inefficient and as such the majority of savings could be made by optimising the existing systems at low cost. Estimated capital costs were$22,600 with a simple payback period of 0.7 years. Additional recommendations include conducting a detailed audit of the compressed air system, the recommissioning of two buildings, ongoing monitoring of individual building energy consumption and updating HVAC maintenance plans

Manufacturing Energy Consumption and Assessment for Us Small and Medium Sized Manufacturers

U.S. Manufacturing sector consumes remarkable amount of energy while the energy efficiency is quite low. Energy consumption of CNC machines is significant and various empirical models have been developed to model the Specific Energy Consumption (SEC) of CNC machines. However, most of the models are developed for specific machines, hence have limited applications in manufacturing industry. In this research, a general empirical SEC model for milling machine at certain power level is developed based on actual cutting experimental data. In this model, stand-by power and spindle power are used in the SEC model for the first time. The Material Removal Rate (MRR) is used to represent cutting parameter. The proposed model is fitted by regression analysis and validated using experimental data. Results show that the proposed model can be applied on various milling machines with an average absolute residual ratio of 6%. The model is also validated through a series of cutting experiments on a machine center, with an accuracy of 91.5%, for the SEC calculation. Compressed Air Systems (CAS) are the 3rd energy source in industrial facilities and has a significant impact on the energy efficiency of manufacturing systems. This thesis provides an overview of all typical energy conservation measures (ECM) for CAS as well as all the energy savings calculations methods. To provide a simple guideline for decision maker, an economic benchmark analysis is presented for typical ECMs using the baseline conditions from Technical Reference Manuals (TRM) of multiple States in the US. Due to the ECMs correlate with each other, the comprehensive savings from multiple ECMs is not the simple summation of each individual measure. An integrated model is proposed to investigate the interrelationships of all measures and obtain combined savings. Meanwhile, the dryer’s impact to the other ECMs is included for the first time in the proposed model. CAS is a dynamic system with changing load, operations, and specifications etc. Therefore, the savings is a variable depending on system situations. The reliabilities of the ECMs are analyzed to obtain their dynamic characteristics. The optimization of the ECMs is discussed to demonstrate the interrelationships and dynamic of the savings mechanisms. While the above studies focus on the energy modeling and savings of important system of manufacturing activities, it is important to have an overall understanding of the energy efficiency and saving potentials. Energy intensity is commonly used as an indicator for the energy efficiency. Encourage the implementation of proposed ECMs is the main strategy for energy efficiency improvement programs to influence the plant’s energy intensity. Study the trends of energy intensity of SMEs and the acceptance of proposed ECMs could draw outlines of the changes of energy usage, understand the flavor of plant managers towards energy savings projects and reflect the shift of technologies in the past decades. This thesis found that the industry structure of SMEs had limited effects on the energy usage while the fluctuation of producing activities and improvement of energy efficiency were the main contributors over the past three decades. Compared with the manufacturing plants with best energy efficient practices, an average of 15.71% of electricity and 14.51% of natural gas could be saved. However, the saving potentials of each subsectors varies dramatically due to the differences of production processes and energy use strategies. This discrepancy also reflected on the implementation of ECMs. Special planning and stimulations should be developed to accommodate the unique saving demands for different industries, ECM types and regions

An Analysis of the Viability of 3D-Printed Construction as an Alternative to Conventional Construction Methods in the Expeditionary Environment

Conventional construction is believed by some to have reached its technological limit of performance, making it increasingly difficult for conventional construction methods to meet the U.S. military’s core standards of quality, cost, and timeliness in the expeditionary environment. While still in its infancy, 3D-printed construction has the potential to revolutionize the way the military performs construction in deployed environments. This research conducts a systematic review of the viability of 3D-printed construction to investigate whether or not it is now or could be a viable replacement for conventional construction methods, specifically in remote environments where conventional construction capability may be limited. This research then evaluates seven key viability factors – materials, structural design, process efficiency, logistics, labor, environmental impact, and cost – as they apply to two recent, military-run 3D-printed construction case studies, before drawing conclusions regarding the current viability of 3D-printed construction. Finally, this research suggests areas in which further research and development is needed in order to ensure the effectiveness of 3D-printed construction in the expeditionary environment

A Study of Cleaner Production and Eco-Efficiency Uptake within Western Australian Small Medium-Sized Enterprises, with a Specific Focus on Air Emissions and Related Air Quality

This thesis examined the uptake of Cleaner Production and Eco-Efficiency within Western Australian Small-Medium Industries, with a specific focus on Air Emissions. It was found that, given the lack of governmental supporting and the low value of most air emissions, the CP methodology is ineffective as a means of minimising the release of low value air emissions (or emissions generated from low value product). It was therefore concluded that a holistic approach is required

TEchMA2020: 3rd International Conference on Technologies for the Wellbeing and Sustainable Manufacturing Solutions: book of abstracts

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The sustainable materials roadmap

Over the past 150 years, our ability to produce and transform engineered materials has been responsible for our current high standards of living, especially in developed economies. However, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of the economy, energy, and climate. We are at the point where something must drastically change, and it must change now. We must create more sustainable materials alternatives using natural raw materials and inspiration from nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments (LCAs) based on reliable and relevant data to quantify sustainability. We need to seriously start thinking of where our future materials will come from and how could we track them, given that we are confronted with resource scarcity and geographical constrains. This is particularly important for the development of new and sustainable energy technologies, key to our transition to net zero. Currently 'critical materials' are central components of sustainable energy systems because they are the best performing. A few examples include the permanent magnets based on rare earth metals (Dy, Nd, Pr) used in wind turbines, Li and Co in Li-ion batteries, Pt and Ir in fuel cells and electrolysers, Si in solar cells just to mention a few. These materials are classified as 'critical' by the European Union and Department of Energy. Except in sustainable energy, materials are also key components in packaging, construction, and textile industry along with many other industrial sectors. This roadmap authored by prominent researchers working across disciplines in the very important field of sustainable materials is intended to highlight the outstanding issues that must be addressed and provide an insight into the pathways towards solving them adopted by the sustainable materials community. In compiling this roadmap, we hope to aid the development of the wider sustainable materials research community, providing a guide for academia, industry, government, and funding agencies in this critically important and rapidly developing research space which is key to future sustainability.journal articl