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Design for Sustainability and The

Environment

Chapter 10

1 Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

Design for Sustainability & The

Environment

2

� The ecosystem of planet Earth is human-dominated.

� The standard of living of humans is due to their ability to develop technology to dominate the ecosystem.

� Significant is the human alteration of the planet that some scientists declare present times to represent a new geological era: the Anthropocene era:

� Known as the age of the human.

� Today’s designers and engineers are expected to move beyond design for recyclability, beyond design for the environment to design for sustainability.

Dieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

10.1 The Environmental

Movement

What are the basics of environmental movement?


Ecosystems and Balance

4

� Basic biological ecosystems maintain balance by adhering to canons developed through evolution:

� Use waste as a resource

� Diversify and cooperate to fully use the habitat

� Gather and use energy efficiently

� Optimize rather than maximize

� Use material sparingly

� Don’t foul nests

� Don’t draw down resources

� Remain in balance with the biosphere

� Run on information

� Shop locallyDieter/Schmidt, Engineering Design 5e. ©2013. The McGraw-Hill Companies

United States Environmental Movement

� Through history there have been cases of naturalists, scientists, social workers, and politicians who have publicized issues of sanitation and improper waste handling, conservation of natural resources and pollution.

� The Environmental Protection Agency was consolidated from smaller governmental units into one agency by President Richard Nixon in 1970.

� www.epa.gov


Measures of Environmental Impact

� A key concept in environmental science is the quantification of the impact of humans and technology on the environment.

� IPAT equation was developed in the 1970s to model the interaction of population with the environment:

��

= �� × �� × ��

= � × � × �

� Allenby’s interpretation of the IPAT equation:

�� =

�� × (�� !� ��

"��#) × (

�#%&��#�'#()*&'")!(

#&(�+�� !� ��)


Interaction of Energy Use with the

Environment

� Modern society has been built with a dependence on fossil fuels:

� Coal

� Oil

� Natural gas

� There are economic concerns about the stability of our energy supply (specifically oil).

� 1973 Oil crisis:

� The increase in environmental awareness in the 1970s coincided with the first serious shock to the U.S. oil supply.


Behavior Changes As a Result of the

U.S. Environmental Movement

� The environmental movement has already produced a great impact on changing attitudes and behaviors of citizens, governments, and businesses.

� Environmental science principles are now engrained in the education system and taught to children in K-12 classrooms.

� Most U.S. citizens view recycling as separating their waste into different streams as it comes out of their home and businesses.


2009 Data on Disposition of Municipal

Solid Waste (MSW)


10.2 Sustainability

What does sustainability mean?


Sustainability

� Sustainability is a term that has come into popular culture as a characteristic of national fiscal policy, personal budgetary policy, and environmental policy.

� A formal definition of sustainable development was established by a report titled “Our Common Future”:

� Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.


WCED Report on Sustainability

� Critical objectives for environment and development policies that follow from the concept of sustainable development include:

� Revive growth in an economic sense

� Change the quality of growth

� Meet essential needs for jobs, food, energy, water, and sanitation

� Ensure a sustainable level of population

� Conserve and enhance the resource base

� Reorient technology and manage risk

� Merge environment and economics in decision making


Twenty Years After the WCED Report on

Sustainability

� Changes in indicators of global sustainability are as follows:

� World population growth rate is now 1.2% rather than 1.7%

� Malnutrition has increased

� HIV/AIDS cases have increased from 10M to 40M

� CO2 atmospheric concentration has increased from 325 ppm to 285 ppm at an accelerating rate


Measures of Sustainability

� Allenby revises the former metric into a sustainability impact equation:,�-��.��

= �� ×/��

��-��

×-�-��.��0

/��

� There are two changes:

� The affluence term has been broadened from a consumption measure to a more expansive term “quality of life”.

� It emphasizes the social nature of sustainability.


10.3 Challenges of Sustainability

for Business

How do businesses respond to the sustainability movement?


Challenges of Sustainability for

Business

� Protection of the earth’s environment is high on the value scale of most citizens of the world's developed countries.

� Investment firms now offer options of stocks and mutual funds of companies that meet thresholds on corporate social responsibility (CSR).

� Most corporations realize that it is in their best interest to take a strong pro-environment approach to their business.

� Being pro-environment can have repercussions for the bottom line.


10.4 End-Of-Life Product

Transformations

How can the end-of-life product affect the environment?


Options for Transformation at Product

End of Life


Reuse

� Reuse means identifying a new end-user who sees value in the product as it exists at the time of the original user’s plan of disposal .

� Allenby calls this point in a product life cycle the “end of first life.”

� Reuse is common in the case of rebuilt automotive parts like alternators and carburetors.

� Construction materials like bricks, hardwood flooring, and wooden trim pieces can be sometimes recovered from home remodeling or demolition sites.


Remanufacturing

� Remanufacturing is the refurbishing of an existing system by restoring it to near new condition.

� This process can be limited to the cleaning and replacement of worn parts (refurbishing) or the harvesting of key subassemblies for placement into new products.

� Remanufacturing saves energy by reducing the need for the processing of raw materials into new products.

� There are drawbacks to the remanufacturing process from the producer’s point of view:

� It can cut into the new product market share

� The quality of the remanufactured product may be lower than that of the original product.


Recycling

� Recycling is the recovery from the waste stream of products or goods that can be used in the raw materials stream to make the same or similar material.

� Recycling is the end-of-life strategy that is best suited for deriving profit from the waste stream.

� The steps in recycling a material are:

� Collection and Transport

� Separation

� Identification and Sorting


Collection and Transport

� Collection for recycling is determined by the location in the material cycle where the discarded material is found

� Home scrap is residual material from primary material production

� Prompt industrial scrap or new scrap is that generated during the manufacture of products.

� Old scrap is scrap generated from a product which has completed its useful life.

� Collection methods include curbside pickup, buy-back centers, and resource recovery centers where solid waste is sorted for recyclables and the waste is burned for energy.


Separation

� Separation of economically profitable recyclable material from scrap typically follows one of two paths:

� First Path:

� Selective dismantling takes place.

� Second Path:

� The product is subjected to multiple high-energy impacts to shred it into small, irregular pieces.


Identification and Sorting

� The economic value of recycling is largely dependent on the degree to which materials can be identified and sorted into categories.

� Material that has been produced by recycling is generally called secondary material.

� The addition of secondary material to virgin material in melting or molding can degrade the properties of the resultant material if the chemical composition of the secondary material is not carefully controlled.


Energy Recovery Through Combustion

� Incineration reduces the volume of solid waste that needs to go to the landfill by burning the combustible organic material.

� The combustion converts the retained energy of the solid waste into heat, which can be used to generate steam and thus electricity.

� The volume of solid waste is reduce by 50 to 95 percent depending on the effectiveness of the sorting process.

� A modern municipal incineration plant employs considerable technology in order to perform its function without causing objectionable pollution.


Landfill

� A landfill is NOT a trash dump

� A landfill is an airtight, lined, structured containment area for a permanent underground burial site for compacted solid waste.

� Landfills literally fill in space to create more land surface.

� Two challenges to maintaining a landfill are inevitable:

� If leachate breaks through a spot in a landfill, the source of the leak must be discovered and patched.

� The trash in a landfill will decompose in an anaerobic process which creates a mixture of gasses that is composed of about 50% methane and 50% carbon dioxide. Both are potent green house gases.


10.5 Role of Material Selection in

Design for Environment

How can material selection in a design process help environment?


Material Selection Role

� Material selection has a unique role in Design for Environment tools, practices, and methods.

� Design for Environment methods are those that bring the consideration of the entire life cycle of the product into the earliest stages of the design process.

� The material of which a product is made greatly influences the impact of a product on the environment in terms of natural resource use and impact and end-of-life options.


Material Life Cycle

� The life cycle of materials begins from their initial removal out of the earth, through refining and shaping into engineering materials until they must be retired and disposed of in an environmentally safe way.

� Look at Example 10.3.


Selection of Eco-Efficient Materials

� Materials selection plays a major role in each of the phases of product life cycle:1) Material production:

� Reduce mass of material and choose material with low eco-indicators.

2) Part manufacture:

� Select a process with low energy requirement and CO2 footprint

3) Transportation:

� Low mass reduces energy consumption

4) Service in use:

� Thermal and electrical losses are often important and are material dependent.

5) Disposal:

� High recyclability is a strong benefit.30 Dieter/Schmidt, Engineering Design 5e.

©2013. The McGraw-Hill Companies

Life-Cycle Assessment (LCA)

� Life-cycle assessment proceeds in three stages:

1. Inventory analysis:

� The flows of energy and materials to and from the product during its life are determined quantitatively.

2. Impact analysis:

� All potential environmental consequences of the flows catalogued in Step 1 are considered.

3. Improvement analysis:

� Results of steps 1 and 2 are translated into specific actions that reduce the impact of the product or the process on the environment.


10.6 Tools to Aid Design for The

Environment and Sustainability

What are the tools to aid design for the environment and sustainability?


Life Cycle Design Strategies

� Minimize emissions and waste in the manufacturing process.

� Substitute recyclable materials where possible, and use design for disassembly guidelines to improve chances for recycling.

� Increase the useful life of the product, thereby prolonging the time when new material and energy resources need to be committed to a replacement of the product.


Relationship of Design for Sustainability

& Other Design for X topics


Design Guidelines Applying to

Embodiment Design

1. Design for the minimal use of materials and energy:

� Achieve minimum weight without affecting quality, performance, and cost.

� Reduce waste of all types.

2. Design for Disassembly:

� Minimize the number of adhesive and welded joints when it makes sense

� Use removable fasteners and those that are not prone to breakage

3. Design for Maintainability:

� Most products need to be opened to be maintained.


Design Guidelines Applying to End-of-

Life Transformations

� Design for Remanufacturing

� Design for Recycling

� Design for waste recovery and reuse in processing


Design for Remanufacturing

� Characteristics of products that are good candidates for remanufacturing include the following:

� Technology that will be relevant for 7 to 10 years.

� Product redesign cycle of 1 to 4 years.

� Rate of return for remanufacture at 15% or more

� 50 to 75% of parts to be remanufactured

� Modular architecture with distinct separation of materials into different modules


Design for Recycling

� There are several steps that the designer can follow to enhance the recyclability of a product:

� Make it easier to disassemble the product and thus enhance the yield of the separation step

� Minimize the number of different materials in the product to simplify the identification and sorting issue

� Choose materials that are compatible and do not require separation before recycling

� Identify the material that the part is made from right on the part.


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