Post on 25-Dec-2015
Engineering Design: Seeking Sustainable
Solutions
Objectives
By the end of this unit, students will be able to:
1.Broaden design alternatives by brainstorming sustainable alternatives.
2.Use the sustainable design tables to incorporate sustainability into alternatives analysis.
3. Incorporate sustainability into economic analysis by:
• Conducting life cycle cost analysis• Including environmental benefits in cost-benefit analysis
Engineering Design: Seeking Sustainable Solutions
• Review of sustainability and the engineering design process
• 3 strategies for more sustainable design:
1. Broaden design alternatives
2. Incorporate sustainability into alternatives analysis
3. Incorporate sustainability into economic analysis
Review of Sustainability Concepts
What is Sustainability?
• Meeting society’s present needs without compromising the ability of future generations to meet their own needs. (Brundtland Commission, 1987)
Review of Sustainability Concepts
Triple Bottom Line Solutions
• Good for the environment
• Good for economics
• Good for society
Review of Sustainability Concepts
The 3 Pillars• People
– Fair practices for all people and does not exploit interest of separate parties based on money, status or growth.
• Planet– Management of renewable and non renewable
resources while reducing waste.
• Profit– Financial benefit enjoyed by the majority of society.
Steps in the Engineering Design Process
1. Define the problem– Product or customer requirements, functions and features
2. Brainstorm alternative solutions– Products, structures, or processes
3. Prepare preliminary/conceptual design for each alternative
4. Compare alternatives– Includes establishing criteria and conducting alternatives analysis
– Includes economic analysis
Steps in the Engineering Design Process
5. Choose an alternative
6. Perform detailed design on chosen alternative
7. Build/test, modify as needed
• Real-world example
• At what steps could you consider sustainability?
Considering Sustainability in the Engineering Design Process
1. Define the problem– Product or customer requirements, functions and features
2. Brainstorm alternative solutions– Products, structures, or processes
3. Prepare preliminary/conceptual design for each alternative
Sustainability
Sustainability
Sustainability
SustainabilitySteps in bright green will be considered in this lesson.
Considering Sustainability in the Engineering Design Process
4. Compare alternatives– Includes establishing criteria and conducting alternatives
analysis
– Includes economic analysis
5. Choose an alternative
6. Perform detailed design on chosen alternative
7. Build/test, modify as needed
Sustainability
Sustainability
Sustainability
3 Strategies for More Sustainable Design
1. Broaden design alternatives
2. Incorporate sustainability into alternatives analysis
3. Incorporate sustainability into economic analysis
1. Broaden Design Alternatives
• When brainstorming, consider “out of the box” alternatives that may be more sustainable than ordinary ones.
• Sustainable options may or may not be justified in terms of capital cost or other factors.
– Consideration important– More sustainable alternative may turn out to be superior,
especially if sustainability is considered in alternatives analysis and economics analysis
1. Broaden Design Alternatives
Traditional CE Alternatives
Asphalt Road Concrete Road
1. Broaden Design Alternatives
More Sustainable CE Alternatives
Recycled Asphalt Road
Recycled Asphalt Road with a Bike
Lane
1. Broaden Design Alternatives
Traditional CE Alternatives
Concrete channel with a rectangular cross-section Concrete channel
with a trapezoidal cross-section
1. Broaden Design Alternatives
More Sustainable CE Alternative
1. Broaden Design Alternatives
Traditional CE Alternative
Customary Site Design
1. Broaden Design Alternatives
More Sustainable CE Alternative
Implements Non-Structural Runoff Control
1. Broaden Design Alternatives
Traditional CE Alternatives
1. Broaden Design Alternatives
More Sustainable CE Alternative
1. Broaden Design Alternatives
Traditional ME Alternatives
Gasoline Powered Chevy Malibu
Gasoline Powered Nissan Altima Coupe
1. Broaden Design Alternatives
More Sustainable ME Alternatives
Tesla Electric Car• 220 miles on a charge• 0 to 60 in 3.9 seconds
Smart Fortwo
• 2 passengers
• 3-cylinder engine
• 33 mpg city/41 highway
1. Broaden Design Alternatives
More Sustainable ME Alternatives
Honda FC Hydrogen Car
1. Broaden Design Alternatives
Traditional ME/EE Alternatives
Coal-fired power plant
Natural gas-fired power plant
1. Broaden Design Alternatives
More Sustainable ME/EE Alternatives
Solar power facility Wind farm
1. Broaden Design Alternatives
More Sustainable ME/EE Alternative
Coal-fired plant with carbon capture and sequestration
1. Broaden Design Alternatives
More Sustainable IE Alternative
More Sustainable IE Alternative
Practice Brainstorming Sustainable Design Alternatives
2. Incorporate Sustainability into Alternatives Analysis
Traditional Engineering Design Criteria:
• Function• Cost (capital and operating/maintenance)• Safety• Constructability• Durability• Aesthetic appeal
2. Incorporate Sustainability into Alternatives Analysis
Sustainable Engineering Design Criteria:
The previous list plus:• Impact on people (society)• Impact on the planet (environment)
2. Incorporate Sustainability into Alternatives Analysis
Sustainability Aspects to Consider in Engineering Design
Life Cycle Stage →Sustainability Aspect ↓
1. Materials Acquisition
2. Construc-
tion
3. Use 4. Demolition
a. Material use
b. Energy use
c. Water use
d. Solid waste generation
e. Emissions generation
f. Toxic releases
g. Land impact
2. Incorporate Sustainability into Alternatives Analysis
Sustainable Design Tables
• Handout
• Exercise
3. Incorporate Sustainability into Economic Analysis
Methods of Comparing Alternatives
• Present worth, annual payments, future worth analysis
• Break-even comparisons
• Rate of return (ROR), incremental rate of return (IROR) analysis
• Cost-benefit analysis
Life cycle cost analysis
Quantify environmental benefits
Use a lower discount rate
3. Incorporate Sustainability into Economic Analysis
Life Cycle Cost Analysis
• In choosing among engineering project/product alternatives, consider life cycle costs, or the total cost of ownership over the life of the project/product.
• Also called “cradle to grave" or "womb to tomb" costs.
• Useful in present worth, annual payments, future worth analysis (methods that compare costs of alternatives), and in break-even comparisons if benefits are not included
3. Incorporate Sustainability into Economic Analysis
Life Cycle Cost Analysis
• Phases of project/product life to consider:– Planning – Design – Construction/production– Operations – Maintenance, renewal/rehabilitation – Replacement or disposal
3. Incorporate Sustainability into Economic Analysis
Life Cycle Cost Analysis
• What phases of project/product life cycle are traditionally considered in alternatives analysis?
• Why might using full life cycle cost analysis benefit the environment?
3. Incorporate Sustainability into Economic Analysis
Life Cycle Cost Analysis
Example problem
3. Incorporate Sustainability into Economic Analysis
Quantify Environmental Benefits
Methods of comparing alternatives that include benefits:
• Rate of return (ROR), incremental rate of return (IROR) analysis
• Cost-benefit analysis
In evaluating benefits, be sure to quantify environmental benefits so they are not excluded.
3. Incorporate Sustainability into Economic Analysis
Quantify Environmental Benefits
• Suppose that a city is doing a cost-benefit analysis for how to use a piece of land. Two alternatives include:
1. Allowing a developer to construct a shopping mall, and
2. The “do nothing” alternative – leave the land as a forest.
• How would you quantify the costs associated with each alternative?
• How would you quantify the benefits associated with each alternative?
3. Incorporate Sustainability into Economic Analysis
Quantify Environmental Benefits
• Quantifying environmental benefits is typically difficult, so environmental benefits historically have often been left out.
Ways to quantify environmental benefits:• Surrogate markets• Surveys
– Willingness to pay to visit a park– Willingness to pay to use an HOV lane–
3. Incorporate Sustainability into Economic Analysis
Quantify Environmental Benefits
Ways to quantify environmental benefits:
• Health benefits
– Air pollution caused by an industry may cause people to miss work. A dollar value can be assigned to missed work using salaries. Installing an air pollution control device would have a quantifiable health benefit of fewer people missing work.
– Health care costs attributable to air quality
–
• Other
3. Incorporate Sustainability into Economic Analysis
Quantify Environmental Benefits
• Cost-benefit analysis: Used to choose among engineering project/product alternatives
• For each project alternative, calculate the ratio of benefits to costs, with all benefits and costs adjusted for the time value of money (typically everything is adjusted to present).
• Choose the option with the highest benefit-cost ratio or net benefit
3. Incorporate Sustainability into Economic Analysis
Quantify Environmental Benefits
• PVB (present value of benefits)
• PVC (present value of costs)
• BCR (benefit cost ratio) = PVB / PVC
• Net benefit = PVB - PVC
3. Incorporate Sustainability into Economic Analysis
Quantify Environmental Benefits
Example problem – Cost-benefit analysis
3. Incorporate Sustainability into Economic Analysis
Use a Lower Discount Rate
• Another way to consider sustainability in all types of economic analysis: use a lower discount rate
• A high discount rate implies a very low value on the welfare of future generations
Summary