Manufacturing System Energy Modeling and Optimization

World energy consumption has continued increasing in recent years. As a major consumer, industrial activities uses about one third of the energy over the last few decades. In the US, automotive manufacturing plants spends millions of dollars on energy. Meanwhile, due to the high energy price and the high correlation between the energy and environment, manufacturers are facing competing pressure from profit, long term brand image, and environmental policies. Thus, it is critical to understand the energy usage and optimize the operation to achieve the best overall objective. This research will establish systematic energy models, forecast energy demands, and optimize the supply systems in manufacturing plants. A combined temporal and organizational framework for manufacturing is studied to drive energy model establishment. Guided by the framework, an automotive manufacturing plant in the post-process phase is used to implement the systematic modeling approach. By comparing with current studies, the systematic approach is shown to be advantageous in terms of amount of information included, feasibility to be applied, ability to identify the potential conservations, and accuracy. This systematic approach also identifies key influential variables for time series analysis. Comparing with traditional time series models, the models informed by manufacturing features are proved to be more accurate in forecasting and more robust to sudden changes. The 16 step-ahead forecast MSE (mean square error) is improved from 16% to 1.54%. In addition, the time series analysis also detects the increasing trend, weekly, and annual seasonality in the energy consumption. Energy demand forecasting is essential to production management and supply stability. Manufacturing plant on-site energy conversion and transmission systems can schedule the optimal strategy according the demand forecasting and optimization criteria. This research shows that the criteria of energy, monetary cost, and environmental emission are three main optimization criteria that are inconsistent in optimal operations. In the studied case, comparing to cost-oriented optimization, energy optimal operation costs 35% more to run the on-site supply system. While the monetary cost optimal operation uses 17% more energy than the energy-oriented operation. Therefore, the research shows that the optimal operation strategy does not only depends on the high/low level energy price and demand, but also relies on decision makers’ preferences. It provides not a point solution to energy use in manufacturing, but instead valuable information for decision making. This research complements the current knowledge gaps in systematic modeling of manufacturing energy use, consumption forecasting, and supply optimization. It increases the understanding of energy usage in the manufacturing system and improves the awareness of the importance of energy conservation and environmental protection

Low-grade Heat Recovery for Sustainable Automotive Manufacturing

PhD ThesisIn response to the need for UK manufacturing to decarbonise its production processes and become more sustainable, an increasing interest has been given to low-grade heat recovery technologies able to energy-efficiently control the temperature and humidity of the air supplied for product-specific applications. This study aims to investigate the novel use of liquid desiccant technology in automotive painting. The work includes a literature review on automotive manufacturing and painting to analyse processes, energy consumption, waste heat sources and the importance of temperature and humidity control, identifying how the liquid desiccant technology could match these conditions. Based on the knowledge of the main operating factors of the liquid desiccant technology, a framework for the techno-economic feasibility analysis of different heat recovery scenarios was developed. The techno economic analysis proposed new correlations for the analysis of the heat and mass transfer in the dehumidifier and regenerator of the liquid desiccant system able to predict the performance of the system under different conditions. Novel configurations for the use of liquid desiccant technology in the field of low-grade heat recovery and painting processes were designed and case studies were carried out to estimate the energy and economic performance of the designed novel configurations. Also, the performance of the technology in different outdoor air conditions, such as hot and humid climates, was estimated and compared with the UK. The case studies showed that the potential for heat recovery from transformers, compressors and thermal oxidisers and its use for air-conditioning, painting operation and air dehydration are high enough to achieve significant energy savings in terms of natural gas and electricity. Also, significant energy savings for cooling and dehumidification are achievable by employing the technology in hot and humid climates. Potential innovative solutions to increase the energy and economic performance of the liquid desiccant technology for automotive painting were also recommended. It was concluded that energy-efficient use of low-grade heat sources to drive the liquid desiccant technology could help the automotive industry to reduce its energy consumption and increase the sustainability of its production process

Best Environmental Management Practice in the Fabricated Metal Product manufacturing sector

This report encloses technical information pertinent to the development of Best Environmental Management Practices (BEMPs) for the Sectoral Reference Document on the Fabricated Metal Products manufacturing sector, to be produced by the European Commission according to Article 46 of Regulation (EC) No 1221/2009 (EMAS Regulation). The BEMPs, both of technological and management nature (identified in close cooperation with a technical working group) address all the relevant environmental aspects of the Fabricated Metal Products manufacturing facilities. The BEMPs described in this report provide guidance on the cross-cutting issues and optimisation of utilities of the manufacturing facilities. Moreover, the BEMPs cover also the most relevant manufacturing processes, looking at energy and material efficiency, protecting and enhancing biodiversity, using of renewable energy and using rationally and effectively chemicals e.g. for cooling of various machining processes. Each BEMP gives a wide range of information and outlines the achieved environmental benefits, appropriate environmental performance indicators to measure environmental performance against the proposed benchmarks of excellence, economics etc. aiming at giving inspiration and guidance to any company of the sector who wishes to improve its environmental performance.JRC.B.5-Circular Economy and Industrial Leadershi

Simulation of Energy Savings in Automotive Coatings Processes

Recently, the automakers have become more and more aware of the environmental and economic impact of their manufacturing processes. The paint shop is the largest energy user in a vehicle manufacturing plant, and one way to reduce costs and energy usage is the optimization of this area. This project aims at providing a tool to model and simulate a paint shop, in order to run and analyze some scenarios and case studies, helping to take strategic decisions. Analytical computations and real data were merged to build a tool that can be used by FCA for their Sterling Heights plant. Convection and conduction heat losses were modeled for the dip processes and the ovens. Thermal balances were used to compute the consumptions of booths, decks and ovens, while pump and fan energy consumptions were modeled for each sub-process. The user acts on a calendar, scheduling a year of production, and the model predicts the energy consumption of the paint shop. Five scenarios were run to test different conditions and the influence of scheduling on the energy consumption. Two different sets of production schedules have been evaluated, the first one fulfilling the production requirement in one shift of 10 hours, at high rate, the second one using two 7-hour-long shifts at medium production rate. It was found that the unit cost was minimized in the warmest months of spring and fall, and system shutdown was a crucial factor to reduce energy consumption. A fifth hypothetical scenario was run, with a 4 month continuous production and an 8 month total shutdown, which reduced the energy consumption to a half of the best realistic scenario. When the plant was run in a two-shifts configuration, the cost to coat a vehicle was found to be $29 with weekend shutdown, and$39 without. In the one-shift configuration, the cost was slightly higher, but the difference was less than 5%. While the fifth scenario showed a consistent reduction of the unit cost, inventory and logistic expenses deriving from the production strategy make this scenario almost impossible to realize. A sensitivity analysis was run on several parameters influencing the energy consumption of the paint shop, and the booths set point temperature was found to be the most significant factor

A techno-economic evaluation of low-grade excess heat recovery and liquid desiccant-based temperature and humidity control in automotive paint shops

The paint shop is the most energy-intensive process in an automotive manufacturing plant, with air management systems that supply air to paint booths consuming the most energy. These systems are crucial for temperature and humidity control, in which they ensure the quality of the final product by preventing paint defects and thus avoid the additional cost of reworking. This is especially true for water-based paints, in which evaporation and film formation processes are influenced by the temperature and humidity of the surrounding air. This study aims to investigate the incorporation of liquid desiccant technology into a conventional air management system for paint shops operating in different climates, which presents the novelty of the study. The technology is promising because it can regulate humidity, act as a dehumidifier or humidifier depending on the demand and stores energy in a thermo-chemical form. In addition, waste heat sources available in the paint shop can be used for the regeneration of the liquid desiccant solution. The techno-economic evaluation of this novel process indicates that the proposed system can control the temperature and humidity of the supply air within the range required for optimal painting and achieve significant energy savings in both cold and hot/humid climates, with a reduction of 44.4% and 33.6% of the energy cost compared to the conventional operation and a payback period of 6.15 and 5.74 years respectively, using calcium chloride as the desiccant solution. The sensitivity analysis investigates the effect of the energy and carbon price on the performance of the system. It is concluded that the integration of liquid desiccant technology into conventional air management systems for paint booths has a huge potential to increase the energy-efficiency of automotive painting

A Framework for Environmental and Energy Analysis of the Automobile Painting Process

AbstractThe automobile industry is experiencing many challenges that affect its sustained growth. The increasing cost of energy used at production plants is often identified as one of the main challenges. Environmental regulations also pose pressure on industry. Within the automobile manufacturing stages, the painting process is the most energy intensive. In this work, a framework for a European collaborative project is presented. The utility of the framework is briefly presented to highlight improvement opportunities to lower energy consumption and environmental impact of a plastic part paint shop

Evolution of the Automotive Body Coating Process—A Review

Automotive coatings and the processes used to coat automobile surfaces exemplify the avant-garde of technologies that are capable of producing durable surfaces, exceeding customers’ expectations of appearance, maximizing efficiency, and meeting environmental regulations. These accomplishments are rooted in 100 years of experience, trial-and-error approaches, technique and technology advancements, and theoretical assessments. Because of advancements directed at understanding the how, why, when, and where of automobile coatings, the progress in controlling droplets and their deposition attributes, and the development of new technologies and paint chemistries, a comprehensive and up-to-date review of automobile coatings and coating technologies was considered to be of value to industrial practitioners and researchers. Overall, the critical performance factors driving the development and use of advanced automotive coatings and coating technologies are (a) aesthetic characteristics; (b) corrosion protection; (c) mass production; (d) cost and environmental requirements; and (e) appearance and durability. Although the relative importance of each of these factors is debatable, the perfection of any one at the expense of another would be unacceptable. Hence, new developments in automotive coatings are described and discussed in the following review, and then related to improvements in production technologies and paints. Modern automotive coating procedures are also discussed in detail. Finally, an extrapolation into the future of automotive coating is offered with a view of the developments and technologies needed for an increasingly efficient and more sustainable coatings industry