Sample Dissertation On Eco Informed Material Selection For Product Design For Mechanical Engineering
Material selection is one of the most critical step in any product design. There are so many engineering materials available for manufacture of various products. However, not all materials qualifies to be used at any given product design. The product designed dictates the selection of material based on the properties of the material, availability, cost, and other attributes. Not all materials undergo the same process from extraction to processing. Even once they are processed and ready for use in manufacturing, not all engineering materials undergo the same process to produce a product. Finally, at the end of their service life, some materials can be easily recycled and used to produce the same parts again while some are impossible to recycle and hence they are just rejected and new materials are produced right from raw material extraction. Materials possess various amounts of embodied energy in them. A life cycle analysis can be used to determine materials energy consumption throughout its life cycle. LCA can be from cradle—to-gate or cradle-to-cradle. Life cycle analysis also helps in understanding carbon footprint of materials by analysis of the energy used during their life cycle. This shows that the decision to select a particular material has environmental impact. As such material selection for product design has to be done with the environmental consequences in mind. This work begins with Chapter 1. In this chapter, an introduction which highlights eco-informed selection of engineering materials for product design is briefly discussed. This is then followed by Chapter 2. It is a literature review of materials where aspects such as materials and environment, tracing the origin of materials, materials life cycle and life cycle assessment, strategy of material selection, eco-audit, and embodied energy are discussed. A methodology on how to select materials is described after literature review. The identified method for this case is CES. Chapter 3 is an elaborate analysis of the eco-audit of various candidates identified for product design. Eco-audit was used to identify eco-friendly materials suitable for product design. Chapter 4 is conclusion and recommendation. This is where important points regarding the study are summarized. Recommendations of the way forward and what can be improved in future is also given in this chapter.
Methodology for Using Life Cycle Assessment (LCA)
LCA is an important tool in material selection for product design. LCA reveal more information about the materials, processes, and products and their corresponding environmental impact. The following is a step-by-step procedure for conducting a Life Cycle Assessment for an engineering material. The LCA process that shall be adopted here involves four main steps:
Goal and scope definition,
Impact assessment, and
Goal and scope definition.
The aim of conducting LCA is to determine the level of environmental impact of various materials. The scope shall be restricted to only carbon emissions. Carbon footprint shall be the only measure of environmental impact in this case. It will not involve other impacts such as emissions of toxins, nitrogen dioxide, hydrogen sulfide, and so forth.
Life Cycle Inventory done in this case was material energy usage. This involved data collection of energy on the following aspects:
Extraction of raw materials (embodied energy)
Manufacturing processes (amount of energy consumed)
Transportation of materials (amount of energy consumed)
Material usage (amount of energy consumed)
Disposal (amount of energy consumed)
End of Life (amount of energy saved by recycling upon end of its useful life)
Life Cycle Impact Assessment.
Carbon emissions affect environment since it is one of the greenhouse gases associated with global warming and climate change. The assessment involved data collection of carbon emissions on the following aspects:
Extraction of raw materials (embodied carbon)
Manufacturing processes (quantity of carbon emissions)
Transportation of materials (quantity of carbon emissions)
Material usage (quantity of carbon emissions)
Disposal (quantity of carbon emissions)
End of Life (carbon emissions reduced by recycling material upon end of its useful life)
Data gathered was interpreted by comparing materials based on their energy and carbon emissions. Comparison of data for various materials helped in identifying the most eco-friendly and the worst eco-friendly materials.
The life of a material from extraction, manufacture/processing, transportation, and use to disposal vary from one material to another. While some require a lot of energy to extract, others just require a little amount of energy. Materials like aluminum require a lot of energy to extract while some materials like high density polyethylene just require a small fraction of energy. On the other hand, certain materials can be recycled and used again and again and in the process energy that would have been otherwise used to extract raw materials is saved. However, recycling some materials results in saving a small amount of energy. Investigations have shown that there is a direct correlation between energy consumed and carbon emitted. Besides embodied energy, there is a need to also consider end-of-life energy potential to determine how much energy is saved by recycling a particular material. In the long run, a material that is recyclable with huge savings in energy is better than a material with little embodied energy but which cannot be recycled or recycled with negligible savings in energy. A decision to choose a material with high embodied energy is a decision to choose a material with greater carbon footprint since energy generation is directly proportional to the amount of carbon emitted (Haynes, 2013). This is true for a power generation that utilize fossil fuels as a source of power. The more the power requirements, the more the fuel need and so the more the carbon emitted. Carbon emission has an impact on environment. It is one of the sources of pollution. Carbon is one of the greenhouse gases that has been blamed for global warming and climate change (Solomon et al, 2009). Materials with a lot of net energy exhibit higher levels of carbon footprint. When performance of materials is just within acceptable limits, the best idea is to choose a material with a lower carbon foot print. Even if it is inevitable to choose a material with higher carbon footprint, the next idea should be to try to lower carbon footprint during its extraction, processing, transport, use, disposal, and recycling by resorting to clean renewable energy sources (Perry, Klemes, and Bulatov, 2008) such as wind, solar, geothermal, and nuclear energy among others. Opportunities to lower carbon footprint can involve such programs like improvement of energy efficiencies (Worrel, Martin, and price, 1999) in manufacturing plants while in the case of transport, the use of vehicles consuming green fuel such as gasohol or electricity can be employed.
Haynes, R. 2013. Embodied energy calculations within life cycle analysis of residential buildings. [Online] Available at: http://www.etoolglobal.com/wp-content/uploads/2012/10/Embodied-Energy-Paper-Richard-Haynes.pdf [Accessed 23 Aril 2015]
Perry, S., Klemes, J., and Bulatov, I. 2008. Integrating waste and renewable energy to reduce the carbon footprint of locally integrated energy sectors. Energy, 33(10), pp. 1489-1497.
Solomon, S., Plattner, G. K., Knutti, R., and Friedlingstein, P. 2009. Irreversible climate change due to carbon dioxide emissions. Proceedings of the National Academy of Sciences, 106(6), pp.1704-1709.
Worrel, E., Martin, N., and Price, L. 1999. Energy Efficiency and Carbon Dioxide Reduction Opportunities in the U.S. Iron and Steel Sector. Berkeley: University of California Energy Analysis Department.