Materials- Life Cycle Analysis Flashcards
What affects the short and long terms costs of materials?
Short: market forces, political influences, rate of supply and demand.
Long term: deposits depleted, new sources found.
What are stressors?
The penalties that occur because of the way a product is made, used or disposed of that must be considered. Examples include harmful emissions, particulates, toxic waste.
What does a life-cycle analysis do?
Examines the life cycle of a product. Assesses the eco-impact created by one or more of its phases (points in life cycle). Catalogs and quantifies the stressors.
Four steps of life-cycle analysis
Goal and scope
Life cycle inventory
Life cycle impact assessment
Interpretation
Goal and scope step
Defined performance of a product in measured, practical units, to define a basis for product system analysis and to compare competing products. Clearly define inputs and outputs of a process or product.
Life cycle inventory step
Various inputs and outputs of water, energy, raw materials and releases to air, land and water are quantified for each phase of the life cycle
Life cycle impact assessment step
Environmental burdens identified in inventory stages are qualitatively or quantitatively characterised as to their effects on local and global environments. Current trend in assessment is “less is best” approach.
Less is best approach
Process and product changes are sought that reduce most (or all) wastes, emissions and consumed resources
Interpretation step
Systematic technique to identify, quantify, check and evaluate information from the results of the LC inventory and/or LC impact assessment.
Includes: identification of significant issues based on results of the LCI and LCIA phases. Evaluation of study considering completeness, sensitivity and consistency of checks. Conclusions, limitations and recommendations.
Highly subjective.
Embodied energy of a material
Hm. The energy (MJ/kg) that must be committed to create 1kg of usable material
Sources of embodied energy
Thermodynamics of processed involved in creating the material.
Transport
Production plant operation
Power plant construction
CO2 footprint
The release of CO2 in creating 1kg of usable material (kg/kg).
How does input-output analysis work to find Hm?
Monitor over a fixed period of time the total energy input to the production plant. Divide this by the quantity of usable material shipped out of the plant.
Processing energy
Hp. The energy (MJ) used to shape join and finish 1kg of the material to create a component or product
Considerations for end-of-life potential
Can the material: be recycled back into the product from which it came, be down-cycled into a lower grade application, be biodegraded into usable compost, be used to yield energy by controlled combustion, be buried as landfill without contaminating the surrounding land.
