Remanufactured products that can substitute for new products are generally claimed to save energy. These claims are made from studies that look mainly at the differences in materials production and ...manufacturing. However, when the use phase is included, the situation can change radically. In this Article, 25 case studies for eight different product categories were studied, including: (1) furniture, (2) clothing, (3) computers, (4) electric motors, (5) tires, (6) appliances, (7) engines, and (8) toner cartridges. For most of these products, the use phase energy dominates that for materials production and manufacturing combined. As a result, small changes in use phase efficiency can overwhelm the claimed savings from materials production and manufacturing. These use phase energy changes are primarily due to efficiency improvements in new products, and efficiency degradation in remanufactured products. For those products with no, or an unchanging, use phase energy requirement, remanufacturing can save energy. For the 25 cases, we found that 8 cases clearly saved energy, 6 did not, and 11 were too close to call. In some cases, we could examine how the energy savings potential of remanufacturing has changed over time. Specifically, during times of significant improvements in energy efficiency, remanufacturing would often not save energy. A general design trend seems to be to add power to a previously unpowered product, and then to improve on the energy efficiency of the product over time. These trends tend to undermine the energy savings potential of remanufacturing.
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 205-213).
The substantial ...growth in industrial production, demand for materials, and population has led to an increasing need for sustainable manufacturing processes to mitigate the negative impacts on the environment and meet the needs of future generations. One proposed direction is remanufacturing, which is a process whereby used products having reached their end-of-life, are restored back to useful service-life. Remanufacturing utilizes the energy and embedded value retained in a product upon reaching end-of-life. Remanufacturing can close the loop between disposal and supply chains, extend the service lifetime of products, conserve resources, and help mitigate environmental consequences attributed to landfilling. Moreover, by preserving the geometrical architecture of cores, remanufacturing can reduce the needs for raw material processing and many manufacturing processes, hence, saving energy. A critical issue to consider when evaluating energy savings in remanufacturing is the product use phase: how well does the remanufactured device perform in the use phase compared to a similar new product from an energy standpoint? To answer this question, we utilize Life Cycle Assessments framework. Using this methodology, we quantify cumulative energy demands of a remanufactured product during its lifecycle and compare it to an equivalent new product. We conduct an analysis of lifecycle energy savings of remanufacturing for 19 different products in 8 distinct product case studies (4 product case studies discussed in detail in this thesis).
(cont.) By performing lifecycle evaluations we conclude that remanufacturing can be a net energy-saving option for products that have energy requirements dominated by the production phase. Moreover, our energy analysis sheds light on the importance of considering use phase while evaluating the energy savings potential of remanufacturing. We conclude that from a total life cycle perspective, remanufacturing may be a net energy saving as well as a net energy expending end-of-life option. We argue that in investigating energy savings of remanufacturing as an end-of-life option, one should also evaluate large-scale critical factors in order to effectively address the systems challenges associated with remanufacturing. Our retrospective approach signifies the importance of studying critical factors such as technological improvements, policy interventions, economic incentives, and business models in order to draw inferences about energy and economic savings potential of remanufacturing. In addition, we argue that the generalized claims about remanufacturing as the ultimate end-of-life option are not only subject to dynamic global changes, but also restricted by the limitations in the lifecycle environmental methodologies. Lastly, we conclude that the evaluations for product remanufacturing and energy savings are more valuable and justified if conducted on a case-by-case basis.
by Avid Boustani.
S.M.
