Sustainable Design in Engineering

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Sustainable Design in Engineering

• ECE 0909.403.01 and 0909.504.02
• Lecture 7b - Performing a Life Cycle Assessment
• 7 March 2002
• Peter Mark Jansson PP PE MScEng

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Aims

• More on Life Cycle Assessment
• LCA Goal definition
• What is it really?
• LCA Scope definition
• How is it established?
• Functional Unit, Reference Product and Data
  Reference

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Definitions, again

• Product the device or process that is the
  functional unit defined for purposes of a LCA.
  The functional unit clearly defines the service
  that the product provides

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Examples of Functional Units

• From the Text see p. 22
• Tea serve as a drink container for 200 cc hot
  beverage 3x daily for one year
• Tidy Hair maintain tidy hair for one year
• Lawn Mow 100m2 of lawn for one year

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Note

• A functional unit (or product), in itself, has no
  environmental impact.
• The environmental impact of the product lies in
  its
• Past (materials extraction, manufacture, use)
• Present use
• Future (use, disposal)

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More definitions

• Product System the processes of the lifecycle
  of the product from material extraction, through
  manufacture, use and disposal (including any
  associated side streams)
• Process any one of the above
• Exchanges (with the environment) an input to
  the process, an output from the process. Or an
  internal interaction with a worker in the process

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Now.What is LCA?

• A life cycle assessment (LCA) is an environmental
  analysis of a product that includes the following
  four phases
• 1. Goal definition 2. Scope definition
• 3. Inventory 4. Impact assessment
• An LCA defines and quantifies the service
  provided by a product, quantifies the
  environmental exchanges caused by the way in
  which that service is provided, and ascribes the
  potential impacts of those exchanges to the
  service

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Goal definition queries

• What is the objective or purpose of the LCA?
• Who is the target group?
• For what will the results of the LCA be used?
• What decisions can be made on the basis of the
  LCA?
• NOTE
• Nature and extent of decisions can only be
  estimated when the LCA has commenced (and they
  may/will be revised iteratively)
• Four primary applications of LCA
• Two are focusing, two are selecting

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Goal definition (cont.)

• Focusing Applications use an LCA for
• Generating environmental information on the
  products expected life through an environmental
  assessment of references
• Identifying improvement potentials, contrasting
  different approaches or designating environmental
  focus point through an environmental diagnosis

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Goal definition (cont.)

• Selecting Applications use an LCA for
• Comparing alternative solutions at the concept
  level
• Comparing alternative solutions at the detail
  level

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Goal definition

• What is it really?
• Goal definition consists of clarifying what the
  LCA can and cannot be used for, including the
  decisions which it must support and the
  environmental consequences to which these
  decisions can lead.

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Sample Goals

• Most LCAs are undertaken to satisfy multiple
  goals (almost always at least 1 and 2)
• 1. Environmental assessment of references
  identify products most significant resource
  consumptions, env. impact potentials and impacts
  on the working environment, also identifying
  which components and which stages of product life
  have the most significant contribution to those
  impacts.
• Answers the Question Which resource consumptions
  and impact potentials are most important?

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Sample Goals (cont.)

• satisfying multiple goals
• 2. Environmental diagnosis reviews options for
  improving the product from an environmental point
  of view, assess the consequences of changes in
  the the product.
• Answers the Questions What is the problem? And
  What can be changed to solve it?

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Sample Goals (cont.)

• satisfying multiple goals
• 3. Environmental specification analyses
  customer perceptions of the product in
  environmental terms and the environmental
  priorities of competitors, creates the new
  product specification based upon the market and
  the assessment and diagnosis.
• Answers the Question What should the new product
  specification be?

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Sample Goals (cont.)

• satisfying multiple goals
• 4. Environmental design of new products
  articulates the environmental considerations that
  have been incorporated into the new product(s),
  quantifies the gains and describes the benefits
  over previous or competing alternatives.
• Answers the Question What changes have been
  introduced by the new product?

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Scope definition

• Objective of the scope definition is
• To identify and define the object of the
  assessment
• And
• To limit the overall study scope to those
  elements critical to the satisfying of the
  established goal(s)

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Scope definition

• Defining the scope means six (6) things
• 1. defining the object of the study, expressing
  it as the service it provides, and defining the
  functional unit.
• 2. selecting one or more reference products or
  reference systems to represent the studys
  object.

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Details of a Functional Unit

• Defined at start
• Qualitative a quality level must be articulated
  so that all options considered on equal footing
  (error rates, accuracy, b/w vs. color TV, etc.)
• Quantitative magnitude of the service as well as
  the duration (product lifespan)

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Value of Functional Unit

• When comparing alternatives
• The service must be experienced as comparable by
  the user for both qualitative and quantitative
  characteristics
• The duration of the service must be the same
• How would you deal with a fluorescent tube with a
  2,000 hour life and one of 20,000 hour life?

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Sample functional unit

• Functional unit
• Supply of 5 cubic meters of water per hour at an
  outlet pressure of 1.5 bar, or correspondingly
  smaller quantity of water at a higher pressure up
  to 5 bar, for 4,870 hours of operation.

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Other Functional Units

• Egg Tray
• TV
• Refrigerator
• Paint
• See text p. 45

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The Reference Product

• Majority of new products represent small changes
  or improvements to existing ones
• As high as 80-90 of environmental impacts of new
  product can be predicted from data on the
  existing product
• Therefore, one of first tasks after functional
  unit is determined is to select one or more
  existing products or technologies to represent it
• Using References are a basic principle in LCA

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The Reference Product (cont.)

• Even for entirely new products (first electric
  car) a good reference can be assembled by piecing
  together its life cycle with the aid of various
  known technologies and processes.
• A distinction between two types of references is
  important here
• Service reference (reference product)
• Data reference (data)

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More definitions

• Service reference or Reference product
• Represents the complete solution which has been
  selected as a way of providing the service of the
  functional unit
• Data reference or Data
• Represent the selected processes or parts of the
  life cycle for the reference product or for
  alternatives to it. The data references
  represent the exchanges of the reference product
  with the environment

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Sample functional unit and reference product

• Functional unit
• Supply of 5 cubic meters of water per hour at an
  outlet pressure of 1.5 bar, or correspondingly
  smaller quantity of water at a higher pressure up
  to 5 bar, for 4,870 hours of operation.
• Reference product
• Grundfos JetpaQ pump
• Data reference see p. 47 in text

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Scope definition (cont.)

• Defining the scope means six (6) things
• 3. Defining which environmental assessment
  parameters are important for the goal of the LCA
  to be satisfied.
• 4. Identifying which processes of the product
  system are the most significant and should be
  included in the LCA, and which are least
  significant and might be excluded, and setting up
  a model for the product system based upon the
  selected references. ( A Paradox)

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Environmental Assessment Parameters

• Environmental impacts
• Resource consumption
• Impact on the working environment
• Divided further into their spatial distribution
  of Global, Regional or Local (see p. 51)

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Example

• Can you think of a Goal for an LCA that would
  directly affect which of these parameters you
  might be most interested in?

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A Paradox

• The scope definition (see 4) requires assessment
  of the product system before data for the
  assessment are collected
• We do this via a rough, introductory
  environmental assessment (or screening) early in
  the projects scope defn. phase

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The Screening

• The basis The reference product parts list
• In the Scope definition phase of an LCA the
  manufacturers parts list is used as a key
  representation of the product in order to define
  its associated product system