sustainability: what does it mean for mechanical engineers?
TRANSCRIPT
Sustainability: What Does It Mean for Mechanical Engineers?
The Sustainability Concept
Triple Bottom Line
People: Good for SocietyFair practices for all people and does not exploit
interest of separate parties based on money, status or growth.
Planet: Good for the EnvironmentManagement of renewable and non renewable
resources while reducing waste.
Profit: Good for the EconomyFinancial benefit enjoyed by the majority of society.
Renewable/Non-renewable Renewable Resources
TimberSurface WaterSolarWind
Non-renewable Resources
Fossil FuelsCoalNatural GasPetroleum
Metal OresAluminumCopper Iron
Waste Management/Resource Conservation Hierarchy
Why is reuse
preferred above
recycling?
Why is recycling preferred
above energy
recovery?Source: www.acmplc.com/Images/hierarchy.jpg
Example: Resource Conservation
A bicycle manufacturer is considering changing from steel wheel rims to rims made from either aluminum or titanium alloy. From a resource conservation point of view, which alternative would you recommend?
Source: Davis, M. L. and Masten, S. J. (2009). Principles of Environmental Engineering and Science, 2nd edition. McGraw-Hill, Boston.
Example: Resource Conservation
Considerations (Partial Listing) Metals are non-renewable resource. Titanium alloy is created by adding other
elements to titanium to improve its properties.
Aluminum is more abundant than titanium Aluminum is more easily recycled than
titanium. Titanium is more durable than aluminum.
Questions: Should decisions be made solely based upon this resource conservation hierarchy? Why or why not?
The Product Life-Cycle
Cradle-to-grave:
Products are assessed at every aspect throughout its entire life cycle
(design to disposal)
Cradle-to-cradle:
Products are evaluated for sustainability and efficiency in
manufacturing processes, material properties, and toxicity as well as
potential to reuse materials
Life Cycle Stages
Creation“Cradle”
Use Demolition
• Design• Material Selection• Site Selection• Manufacturing
Life Cycle Stages
Use UseDemolitio
n
• Distribution• Operation• Maintenance
Life Cycle Stages
Use UseDispos
al“Grave”
• Destruction• Disposal
Example: Biodiesel forCleaner Energy
Life Cycle Stages
Stage 1: Acquire resources, specifically diesel, vegetable oil (such as from crops or waste oil), and other chemicals for processing
biodiesel.
Stage 2: Manufacture biodiesel. This includes the production of
various grades of biodiesel fuels using different processes.
Stage 3: Burn biodiesel fuel to generate power, in particular, for
vehicles.
Biodiesel forCleaner Energy
Sustainability ImpactsPeople:
Provide a more sustainable alternative fuel for existing combustion-based vehicles (stage 3).
Planet: Reuse vegetable oil waste (stage 1).
Emit less CO2 compared to other fuels (stage 3).
Chemical byproducts for other industries (stage 2).
Land usage (stage 2)
Profit: Create alternatives to typical fossil fuel resources (stage 1).
Biodiesel forCleaner Energy
What are the impacts?The performance of biodiesel vs. conventional fuels can be compared by collecting data on fuel efficiency, cost,
emissions, etc.
The properties of the biodiesel can be improved by collecting data on biodiesel manufacturing via different
processes.
Where are better decisions possible?Optimize the performance of biodiesel fuels.
Minimize the cost of the biodiesel powered vehicle.
Analysis for Sustainability Safety
Cost
Manufacturability
Sustainability Other
Material use
Energy use
Waste generation
Water use
Emissions generation
Toxic releases
Other
Sustainable Design Checklist
Example Checklist for Mechanical Design (Partial)Sustainability Metric
Yes/No Questions Alt. A Alt. B
Material Use Are the product materials recyclable or re-usable?Are materials durable ensuring a long usable life for the product? Will deposal of product produce recyclable materials or landfill waste?
Energy Use Is the manufacturing of the product energy intensive?
Waste generation
Will manufacturing or use of the product generate hazardous substances that could pollute?
Other Specify:TOTAL Points