Exercises: The lifecycle of a product

List the stages of a product lifecycle and describe each one using the example of a cotton T-shirt.

Explain what life cycle assessment (LCA) is and what questions it tries to answer about a product.

The figure shows the lifecycle of a product with one stage covered. State which stage is missing and describe what happens during it.

Put the stages of the lifecycle of a wooden pencil in order and describe in one sentence what happens in the first and last stages.

Explain with an example why 'throwing something in the bin' is not the true end of its lifecycle.

Classify these actions according to the stage of the lifecycle they act upon: (a) using reusable bags, (b) designing the product with less material, (c) sorting waste correctly, (d) repairing instead of buying new.

Explain what the carbon footprint of a product is: what it measures and in which stages of its lifecycle it is mainly generated.

Give an example of a product whose main environmental impact is in the use stage and another whose main impact is in manufacturing, and justify both choices.

Compare the lifecycle of a returnable glass bottle with that of a single-use plastic bottle: state in which stages they differ most and why.

In many electronic devices, a significant part of the environmental impact occurs before you buy them. Explain which stages of the lifecycle this statement refers to and give reasons why.

Explain the difference between a 'cradle-to-grave' and a 'cradle-to-cradle' lifecycle, and give an example of a product for each model.

Compare the lifecycle of a paper book with that of an e-reader: in which stages does each concentrate its impact and on what does it depend which option is better?

A pair of jeans requires a huge amount of water throughout its lifecycle. Identify which stages of its lifecycle involve water and propose two specific measures to reduce that consumption.

Explain what ecodesign is by looking at the entire lifecycle: name a design decision that improves each stage (materials, manufacturing, transport, use, and end of life) of a bottle.

A piece of second-hand furniture begins 'another life'. Analyse how its lifecycle changes compared to buying it new and what impacts are avoided.

Compare a reusable bottle that lasts two years with using single-use bottles over that same period (about 500 per person per year). Explain what variables determine which is the better option and in which stages of the lifecycle this comparison takes place.

A sports footwear company wants to redesign its flagship model to reduce its overall carbon footprint. They present you with two technical alternatives based on their LCA:

• Option A: Vulcanized rubber sole and stitched organic cotton upper. Low manufacturing footprint (4,5 kg CO₂-eq), but an estimated lifespan of 400 km and components that are almost impossible to separate at the end of their life.

• Option B: Manufactured entirely from a single polymer (injected mono-material TPU). Higher manufacturing footprint (7,0 kg CO₂-eq), but a lifespan of 1000 km and 100% mechanically recyclable through direct shredding.

1. a) Calculate and justify which of the two options generates a lower impact in CO₂ emissions per 1000 km of use.
2. b) Explain what reverse logistics system the company must implement to ensure that the theoretical end-of-life advantage of Option B is fulfilled in reality.

A supermarket claims: "Our new kraft paper bags are 100% eco-friendly compared to plastic ones." To verify this, they provide you with this simplified excerpt from a Life Cycle Assessment (per bag):

• Paper bag: Carbon footprint: 0,09 kg CO₂-eq; Water consumption: 3,8 L; Estimated average lifespan: 1,5 uses; End of life: 80% recycled or composted.

• Plastic bag (HDPE): Carbon footprint: 0,03 kg CO₂-eq; Water consumption: 0,2 L; Estimated average lifespan: 3 uses; End of life: 20% recycled, 80% landfill/environmental dispersion.

1. a) Refute the advertising claim by calculating the CO₂ emissions and water consumption per 100 shopping trips using both options.
2. b) Justify what environmental dilemma the choice between the two raises: in which life cycle phases is paper more harmful, and in which is plastic clearly worse?

A wireless headphone manufacturer has soldered the lithium battery directly to the motherboard and integrated firmware that locks the device after 400 charging cycles, claiming "safety reasons."

1. a) Identify the two types of obsolescence present (planned hardware and software obsolescence) and describe how they artificially alter the "use" and "end-of-life" phases in the product's life cycle.
2. b) Design three technical modifications (in mechanical joints, component accessibility, and software) so that the product can be repaired by the user and its durability tripled.

Analyze the following simplified data from the Life Cycle Assessment (LCA) of two school backpacks:

• Standard backpack (virgin polyester): Extraction and manufacturing emissions: 18 kg CO₂-eq; Transport: 3 kg CO₂-eq; End of life (landfill, inseparable materials): 1 kg CO₂-eq. Lifespan: 2 years.

• Eco-designed backpack (recycled polyester and modular zippers): Extraction and manufacturing emissions: 9 kg CO₂-eq; Transport: 3 kg CO₂-eq; End of life (mechanical recycling of separated parts): -2 kg CO₂-eq (environmental credit). Lifespan: 6 years thanks to parts replacement.

1. a) Calculate the annual carbon footprint (kg CO₂-eq/year) of each backpack and justify in which phase of the life cycle eco-design achieves the greatest net savings.
2. b) Explain why the end-of-life phase of the eco-designed backpack generates a negative impact (-2 kg CO₂-eq) and what technical design condition is essential for this to happen.

The school cafeteria is planning to replace polypropylene (reusable) cups with disposable PLA ("compostable" polylactic acid derived from corn) cups:

• Manufacturing and transporting each polypropylene cup emits 0,100 kg CO₂-eq. Each wash cycle of a reusable cup in an industrial dishwasher consumes 0,15 L of water and 0,015 kWh (0,005 kg CO₂-eq). The cup withstands 600 washes before being discarded.

• Manufacturing and transporting each PLA cup emits 0,030 kg CO₂-eq. In the municipality, there is no industrial composting facility operating above 60 °C, so organic waste ends up in a landfill.

1. a) Calculate after how many uses the reusable cup becomes more favorable in terms of CO₂ emissions than the single-use compostable cup.
2. b) Predict what will happen to the PLA cup in the landfill (anaerobic degradation) and provide a technical argument on whether the school's decision is an environmental advancement or an instance of "greenwashing".

A smartphone brand annually releases a handset with the same chassis, screen, and processor as the previous one, but altering the color palette, the geometric arrangement of the camera lenses, and introducing continuous on-screen notifications about the battery's "age" once its health drops below 90 %.

1. a) Differentiate "perceived obsolescence" from "functional/planned obsolescence" in this specific case and reason how both influence the product turnover rate and WEEE generation.
2. b) As a future design engineer, propose two technical and aesthetic design solutions (for example, modular or customizable casings) and one consumer or European regulatory measure to curb this phenomenon.

A city is debating two 2-million-euro budget options to manage its packaging waste:

• Option A: Automate the recycling plant to increase the sorting of single-use plastics.

• Option B: Implement a Deposit, Return, and Refund System (DRS) for standardized reusable glass and plastic packaging for local commerce.

1. a) Supported by the life cycle stages (raw material extraction, melting/recycling energy, and material degradation in each cycle), justify why recycling (Option A) does not avoid intensive resource consumption compared to reuse (Option B).
2. b) Identify what new logistical and hygienic stage must be incorporated into the packaging life cycle of Option B for the system to operate safely and efficiently.

You are tasked with redesigning a classroom chair (metal frame, plastic seat and backrest) applying the principles of the circular economy and end-of-life ("Cradle to Cradle").

1. a) Specify which mechanical joining solutions you must choose and which you must strictly reject (such as permanent welds in mixed areas, blind rivets, or contact adhesives) to allow disassembly to be carried out at the school itself using standard tools in under 5 minutes.
2. b) Design the reverse material flow diagram: indicate the technical path each component (steel, thermoplastic) will follow once the chair is retired (primary recycling, remanufacturing, or modular replacement) and how to ensure that no item ends up in a landfill.