MATS6007 Week 3 Sustainable Materials in Infrastructure PDF

MATS6007 Week 3 Sustainable materials system through five material- focused transformative strategies Let’s Save Our Earth  Toward a Sustainable Materials System  Materials alone are not particularly useful. What humans desire is the services...

MATS6007 Week 3 Sustainable materials system through five material- focused transformative strategies Let’s Save Our Earth  Toward a Sustainable Materials System  Materials alone are not particularly useful. What humans desire is the services delivered by materials and products. As a society, we develop infrastructure and devices (or a physical stock of materials) to provide for human activities such as: Sustenance Shelter Communication Education Economic development and enhanced quality-of-life should be decoupled from materials consumption. Such a decoupling requires a profound transition in technology design and in how businesses create value from technology. ❖ Servicizing business models, where use of a product is sold rather than the product itself, aim to make more intensive use of existing stocks ❖ Material-focused transformative strategies The immense scale of steel and concrete production means that any desire to improve the environmental sustainability of materials must involve a shift in these industries. Polymers are not as significant by mass as metals, but nevertheless require a shift because of their large volume fraction in waste streams, continued exponential growth, and persistence in the environment. Five levers to minimise materials impact ❖ Lifetime extension Because so much of materials consumption feeds physical infrastructure, reductions in demand can be achieved through extended service lifetimes by: Improving the durability Maintenance Utilization of existing stocks. Trace contaminants or defects can lead to: Materials degradation Reducing lifetime Reducing recovery potential  Longer life products with delayed replacement In developed economies, where our demand for metal has largely stabilised, we mainly purchase metal as replacement rather than due to growth. If we replace them less often, we will reduce our demand for: New liquid metal, So reduce the environmental impacts of production. Is it more sustainable to keep goods for longer? If developments in technology, legislation or consumer preferences have led to more efficient products, we must evaluate the trade-off between increasing emissions by producing new metal for the replacement, against reducing emissions in use. Predicted product replacement intervals to minimise use and embodied energy  Why do we replace existing goods? Degraded: failure occurs when the product has deteriorated so can no longer perform its original function. Inferior: failure occurs when the original product is still functioning as designed, but a newer product is more attractive. Unstable: failure occurs when the users’ needs have changed so that the original product is no longer as valuable to the existing owner. Unwanted: failure occurs when a product still functions well, but is valued neither by its current owner, nor any other. It may occur due to changes in fashion, or due to legislation  Which specific components drive our replacement decisions? The plate rolling mill is a great example of how the onion skin model explains motivation for life extension: about half the steel in a plate mill is in its structural frame and foundations, and this is a substantial part of the cost of a mill. So rolling mill frames tend to have long life spans, while other components are repaired or upgraded on failure. Onion skin model for rolling mill.  Although a large fraction of its steel is used in the structural core, the cost of steel in an office block is relatively small. So offices, which mainly fail in the ‘unsuitable’ mode, are often replaced rather than upgraded. Onion skin model for office building. For the car, the body and drive-train account for most metal use, but this is a smaller fraction of vehicle material costs, so there is little commercial motivation for life extension. Onion skin model for car  No such inhibition is clear for the fridge where it seems that it is the cost of repair, rather than the value in the components, which motivates replacement over life extension. Onion skin model for fridge.  Of our four case studies, life extension is normal for the plate mill, and one reason for this is that the value shares in the onion skin model are more closely aligned with the metal shares. In contrast, the large fraction of metal at the core of the onion skin models of offices and cars is usually still functioning perfectly when they are discarded, but has a lower fraction of total value. Three solution strategies are relative to the original condition of the product:  Durability (incorporating maintenance and restoration) is about maintaining the original condition for longer; If components are degraded, we have three opportunities for intervention: Design changes may delay the onset of failure Restoration may be possible to return components to their original specification Condition monitoring as part of maintenance in use may allow better prediction of when component replacement or restoration is required All three of these practices are already in use, and could be applied more widely.  Upgrading (including modular and adaptable design) aims to improve on the original design to compete with recent innovations; If the inferior components are in the outer layers of the onion, but the inner layers have significant value, upgrading will be attractive. Design to facilitate future upgrade therefore depends on anticipating which components are likely to require upgrade, and ensuring that the components can be exchanged. Cascading aims to find new users for the product in its current condition which may be as good as originally designed, or partially degraded. For unwanted failures (the hardest to deal with), we may be able to cascade or upgrade, but eventually life extension may not be viable and instead we should promote designs that enable efficient reuse or recycling of the components.  ❖ Dematerialisation Dematerialization refers to the ‘absolute or relative reduction in the quantity of materials used and/or the quantity of waste generated in the production of a unit of economic output. Dematerialisation is closely linked with improving products’ efficiency and with saving, reusing or recycling materials and products It entails actions at every stage of the production and consumption chain: resource savings in material extraction, improved eco-design of products technological innovations in the production process environmentally conscious consumption patterns recycling of waste, etc. Dematerialisation strategies include: the design and manufacture of a smaller product e.g. smaller homes, miniturisation the design and manufacture of lighter products e.g. using alternative construction the replacement of material goods by non-material substitutes (for instance a letter on paper replaced by an email) the reduction in the use of material systems or of systems requiring large infrastructures (for instance using telecommunications instead of using a car to go to work)  Example: Vehicle light-weighting has been enabled by more effective part design and use of alternate materials, including high strength: Steels Aluminium Composites Leading to lower material intensity per part and fuel savings. http://multibriefs.com/briefs/exclusive/automotive_lightweighting_trend_2.html#.XZGY7FUzaUk ❖ Manufacturing efficiency Efficiency refers to the quality and effectiveness of the work being done. The definition is “the ability to do something or produce something without wasting materials, time or energy.” This means that efficiency is often expressed by a percentage, with 100% being the ideal. Industries across the globe rely on the efficiency of their manufacturing processes to create quality products that consumers can afford. The more expensive and inefficient your manufacturing process, the higher the cost of making your products. Manufacturing efficiency is the level of performance within your company, and it's something that can always be improved upon. Evaluate your production lines Identify and Identify eliminat bottlenecks waste Manufacturing efficiency Quantify Improve and training organize practices everything Five ways to improve manufacturing efficiency 1. Identify and eliminate waste One of the biggest sources is material waste in the manufacturing. Short-term: Identify material processes to catch excess material. Short-term: Identify scraps and factory returns for recycling. Long-term: Create less waste with new operational practices and equipment. While identifying where you are creating the most waste, you will find operations that in the long-term, can be improved upon. This could mean anything from adopting new equipment that requires fewer materials to designing new parts that improve yield.  2. Evaluate the production line Throughput is the most important metric to track when studying your production lines. It essentially measures the average number of units being produced over a specific period of time. This allows you to immediately identify problems in your production line when throughput is not up to par on certain machines. Additionally, you can track capacity utilization. By calculating what each factory’s total manufacturing output capacity is, at any given moment, you can see what production lines are performing at their highest possible output.  3. Identify bottlenecks While identifying any problems in your production line, you will naturally discover your largest bottlenecks in production. Bottlenecks are the breakdowns in your production line, supply chain, or any business process that in turn prevents another process from accomplishing its function. For example, in a factory, a specific machine could require maintenance, shutting down its operation for half of a day. Any process that requires that specific machine to be in operation is then stuck, unable to perform. That machine is then the bottleneck. Once you have identified your most common bottlenecks, you can work towards removing them and improving efficiency by eliminating excess downtime due to bottlenecks. 4. Improving training practices In order to empower your employees to create sustainable efficiency, they should be asking themselves these questions: “Is what I’m doing now adding value, or am I just doing it because this is the way I’m supposed to do this?” “If I were the customer, would I pay money for the activities that I am engaged in?” 5. Focus on quantifying and organizing every aspect of the work place First, you must quantify every aspect of your business. Whether you do this with a point value or dollar value, every aspect of your manufacturing process must be quantified. Immediately, this will give you insight into what works and what doesn’t. Second, everything must be organized. From the factory floor to head office, you do not want to let inefficiencies appear simply because of disorganization. Quantifying and organizing your manufacturing process may be two separate activities, but they both accomplish the same goal: long-term manufacturing efficiency.  ❖ Substitution The substitution principle in sustainability is the maxim that processes, services and products should, wherever possible, be replaced with alternatives which have a lower impact on the environment. An example of a strong, hazard-based interpretation of the principle in application to chemicals is: "that hazardous chemicals should be systematically substituted by less hazardous alternatives or preferably alternatives for which no hazards can be identified.  ❖ Recovery & Reform “We already understand the value of sourcing green energy from the sun, similarly we can source valuable green materials from our waste. ‘Mining’ our waste stockpiles makes sense for both the economy and the environment,” A tonne of mobile phones (about 6,000 handsets), for example, contains about 130kg of copper, 3.5kg of silver, 340 grams of gold and 140 grams of palladium, worth tens of thousands of dollars.  Sustainability and Sustainable Materials in Infrastructure  We use the funnel as a metaphor to help visualise the economic, social and environmental pressures on society that are growing as natural resources and ecosystem services diminish and the size of the population and its consumption grows. As our demand increases and the capacity to meet this demand declines, society moves into a narrower portion of the funnel. Opportunities for more sustainable outcomes at typical stages of infrastructure project delivery Pillars of Sustainability The five pillars framework at the early stage of a project is shown with basic levels of achievement, from reducing harm to increasing positive impact. Within each pillar, the four levels of achievement offer the design team a tool for prioritizing its decisions across all five pillars. © Sherwood Design Engineers Solar cells (solar photovoltaic power generation) N-type and P-type layers are stacked on top of each other. Light strikes the crystal induces the ”photovoltaic effect” ❑ In n-type silicon, the electrons have a negative charge ❑ In p-type silicon, the effect of a positive charge is created in the absence of an electron Sun wavelength and the harvested portion of sun energy by solar cells Illustration of the principal losses incurred by a silicon solar cell. - Photons with energies below the band-gap are transmitted straight through the device. - Around 20% of the incident energy is lost this way. The energy of photons exceeding the band-gap is converted into heat. These thermalization losses account for around 35% of the incident energy. - To achieve high efficiencies, novel concepts are needed to reduce these losses Some summarized data for different types of Si solar cells. - Over 95% of all solar cells produced worldwide are composed of Si. - The classical efficiency limit is currently estimated to be 29%. Assignment 2 In your group, each student needs to find one real world example related to one of the five material focused transformative strategies (life time extension, manufacturing efficiency, dematerialisation, and etc) which have been taught in the class. In your group discussions you need to discuss and assess how the strategy can contribute to creating a sustainable system. Based on your assessment, you will propose recommendations for improvement and draw implications for efforts to create a sustainable system more broadly. Students need to fill peer review assessment form (5%). Individual submission (10%) Group Report (5%)