Materials Selection and the Environment Flashcards
Lecture 21
what equation do we use to reduce material consumption?
what equation do we use to reduce energy consumption?
What equation do we use to reduce Carbon emissions?
What do we need to reduce?
Population (P)
Per Capita GDP
Material intensity
Energy intensity
Carbon intensity
If usage of a material increases by r% each year and the current rate of population is P then:
What happens if if r=3%?
If r = 3% more resources used in next 25 years than previous 300 years!
What is the materials lifecycle (simple view)?
When conducting a lifecycle analysis of materials what do we need to consider?
Raw materials, Energy usage, Transport, Environmentsl emissions (Soilds, Liquids and Gases)
At what stages of a materials lifecycle do we conduct an analysis?
Material production, pPopulation manufacturing, Use, end-of-life
What are the environmental impacts?
How do we apply embodied energy to material selections?
Energy used in the primary production of a material or product including transport before use -> can be expressed in energy per kg of materials or energy per unit of product
How do we apply embodied energy to material selections?
Energy used in the primary production of a material or product including transport before use -> can be expressed in energy per kg of materials or energy per unit of product
How do we apply the embodied carbon footprint?
What are the environmental impacts of acidification?
What are the environmental impacts of acidification?
what are the environmental impacts of eutrophication?
over enrichment of water in nutrients;
- phosphates, nitrates
- can result in, for example, algae blooms
- death and decay of algae leads to oxgen depletion
what are the environmental impacts of resource depletion?
Raw materials (Quantites available)
Fuels used (you can only burn fossil fuels once)
Energy in feedstocks (particularly relevant to plastics)
Water
how do you balance multiple impacts?
some approaches try to use a single eco-indicator
what are some advantages of eco-indicators?
places data on commen, normilsed scale
weight different impacts to reflect their importance
what are some disadvantages of eco-indicators?
how do you select weighting factors?
no physical significance
some argue that carbon footprint alone is easier to understand
what not capture by conventional LCA?
social impacts (social life cycle ssessment - often only applied to limited parts of the lifecycle)
unforeseen consequences (more efficient products, cost less to use, increases usage, total energy usage goes up)
What is the embodied energy vs usage energy?
