Design for a Circular Economy | C2.2

The linear economy is characterised by the phrase "take, make, consume, dispose." Resources are extracted from the environment, processed into products, consumed, and then discarded (sent to landfill or incineration) at the end of their life. This model relies on non-renewable energy and generates large volumes of waste. It treats resources as unlimited and end-of-life as inevitable.

The circular economy is a closed-loop system where resources are continuously repurposed, mimicking the closed nutrient cycles of biological ecosystems. Kirchherr et al. (2017) define it as an economic system that replaces the "end-of-life" concept with reducing, reusing, recycling, and recovering materials in production, distribution, and consumption processes. It relies on renewable energy, and examples of materials in circular use include PET beverage bottles (collected, shredded, and remanufactured into new bottles or textiles) and paper and cardboard (continuously recycled into new paper products).

Key comparison:

• Linear: focuses on production efficiency, market consumption, and maximising short-term profit; generates high levels of waste and significant cumulative environmental impact; relies on non-renewable energy and virgin raw material inputs
• Circular: focuses on reuse, recycle, and recover; aims to eliminate waste at the design stage; relies on renewable energy; treats end-of-life materials as inputs for new production cycles rather than disposables

Policy context: In 2020, the European Commission adopted a Circular Economy Action Plan as part of the European Green Deal, targeting climate neutrality (net-zero greenhouse gas emissions) by 2050 and a halt to biodiversity loss by 2025. China uses five-year plan cycles to review and revise its sustainability goals and circular economy targets, embedding them into national economic planning.

线性经济以"获取、制造、消费、丢弃"为特征。资源从环境中提取，加工成产品，被消费，然后在使用寿命结束后被丢弃——送往垃圾填埋场或焚烧。这种模式依赖不可再生能源，产生大量废物，将资源视为无限的，将报废视为不可避免的。

循环经济是一个资源不断再利用的闭环系统，模仿生物生态系统的封闭营养循环。Kirchherr等（2017年）将其定义为在生产、分配和消费过程中以减少、再利用、回收和恢复材料取代"报废"概念的经济系统。它依赖可再生能源，循环使用材料的例子包括PET饮料瓶（收集、粉碎并重新制造成新瓶或纺织品）和纸张及纸板（持续回收成新纸产品）。

主要对比：

• 线性 — 专注于生产效率、市场消费和最大化短期利润；产生大量废物和显著的累积环境影响；依赖不可再生能源和原生原料
• 循环 — 专注于再利用、回收和恢复；旨在在设计阶段消除废物；依赖可再生能源；将报废材料视为新生产周期的投入而非废弃物

政策背景：2020年，欧盟委员会通过了循环经济行动计划，作为欧洲绿色新政的一部分，目标是到2050年实现气候中性（净零温室气体排放），到2025年遏制生物多样性丧失。中国使用五年计划周期审查和修订可持续发展目标和循环经济目标，将其纳入国家经济规划。

One of the most effective means of reducing waste is to address the problem at the design stage, following design-for-manufacture (DFM) guidelines. Designers use a family of "design-for" strategies to eliminate waste and pollution across the full product life cycle:

• Design for materials: select appropriate, low-impact materials; reduce toxic substances, hazardous waste, and polluting emissions; specify single-component materials for moulding (avoiding mixed-material assemblies that cannot be separated for recycling); and mark recyclable materials using resin identification codes for later identification at recycling facilities.
• Design for process: reduce energy consumption and the number of manufacturing steps; minimise production waste, emissions, and the need for secondary operations such as plating, painting, and welding, which add chemical inputs and energy.
• Design for assembly: analyse components and sub-assemblies to reduce the total part count and the variety of fasteners and tool types required; snap-fit and press-fit joints replace adhesive bonds and screws, making products easier to assemble initially and easier to disassemble for repair or recycling at end of life.
• Design for longevity: create longer-lasting products through repairability (standardised spare parts, accessible fixings), upgradability (modular components the user can replace independently), high-quality materials that do not degrade prematurely, timeless aesthetics that do not become unfashionable, and emotional connection that makes users unwilling to discard a product while it still functions. A product that lasts 10 years instead of 2 generates far less waste across its user base.

Dematerialisation is the progressive reduction in the amount of energy and/or material used to produce a product or deliver a service. Examples include email replacing fax and physical surface mail, miniaturisation of electronics, and streaming services replacing physical discs. Dematerialisation directly supports the circular economy by reducing resource inputs per unit of value delivered.

Jevons' Paradox (rebound effect): In 1865, English economist William Stanley Jevons observed that more efficient steam engines led to increased total coal consumption, not a reduction. Cheaper, more effective steam power expanded into new applications (more factories, trains, ships), so total coal use rose even though each engine used less fuel per unit of work. Designers must be aware that efficiency improvements alone cannot be assumed to reduce total resource consumption. If a more fuel-efficient car makes driving cheaper, users may drive more often or further, partially or fully offsetting the gain. Systemic responses and behavioural design (e.g., full-load prompts on appliances) are needed alongside dematerialisation.

减少废物最有效的方法之一是在设计阶段解决这个问题，遵循面向制造的设计（DFM）指南。设计师使用一系列"为...而设计"策略，在产品全生命周期内消除废物和污染：

• 为材料设计 — 选择合适的低影响材料；减少有毒物质、危险废物和污染排放；指定用于成型的单组分材料（避免无法分离回收的混合材料组件）；使用树脂识别码标记可回收材料，以便回收设施日后识别。
• 为工艺设计 — 减少能源消耗和制造步骤数量；最小化生产废物、排放以及对电镀、喷漆和焊接等二次操作的需求，这些操作会增加化学品输入和能源消耗。
• 为装配设计 — 分析组件和子组件，减少总零件数量以及所需紧固件和工具类型的种类；卡扣和压配合接头取代粘合剂和螺钉，使产品最初更易于组装，报废时更易于拆卸以进行维修或回收。
• 为长寿设计 — 通过可修复性（标准化备件、易于接触的固定件）、可升级性（用户可独立更换的模块化组件）、不会过早降解的高质量材料、不会过时的永恒美学以及让用户不愿在产品仍能正常工作时丢弃的情感连接，创造更耐用的产品。使用寿命为10年而非2年的产品，在其用户群中产生的废物要少得多。

去物质化是指逐步减少生产产品或提供服务所使用的能源和/或材料数量。例子包括电子邮件替代传真和实体邮件、电子产品小型化以及流媒体服务替代实体光盘。去物质化通过减少每单位价值所需的资源投入，直接支持循环经济。

杰文斯悖论（反弹效应）：1865年，英国经济学家威廉·斯坦利·杰文斯观察到，更高效的蒸汽机导致煤炭总消耗增加而非减少。更便宜、更有效的蒸汽动力扩展到新的应用领域（更多工厂、火车、轮船），因此尽管每台发动机每单位工作消耗的燃料更少，煤炭总用量仍然上升。设计师必须意识到，单靠效率提升不能假定会减少资源总消耗。如果更省油的汽车使驾驶成本更低，用户可能会更频繁或更远距离地驾驶，从而部分或完全抵消了效益。除去物质化之外，还需要系统性应对和行为设计（例如，家电上的满载提示）。

Biodegradable materials break down through natural biological processes (decomposed by microorganisms) into water, minerals, and organic matter. This end-of-life pathway is fundamentally different from conventional synthetic plastics, which persist in the environment for hundreds of years, fragmenting into microplastics that enter food chains and waterways.

Why biodegradable materials are preferred in a circular economy:

• Provide soil nutrients: when biodegradable products compost, they return organic matter and minerals to the soil, supporting agricultural productivity rather than depleting it
• Reduce landfill waste: biodegradable materials that complete their biological cycle do not accumulate in landfills, freeing capacity and reducing methane generation from anaerobic decomposition of buried organic material
• Lower greenhouse gas emissions: compared to incineration or landfill of persistent plastics, biodegradation (especially aerobic composting) produces lower net greenhouse gas emissions over the material's lifetime
• Regulatory compliance: many jurisdictions are introducing bans or levies on single-use plastics and non-biodegradable packaging; using biodegradable alternatives helps companies avoid fines, comply with regulations, and access markets that require it
• Closed biological cycle: in the circular economy framework, biodegradable materials participate in the biological cycle: they safely re-enter natural systems after use rather than requiring industrial recycling or persisting as pollution

Limitations: Not all biodegradable materials break down under ordinary conditions. Some require industrial composting facilities (specific temperature, humidity, and microbial conditions) that may not exist in the disposal location. Designers must specify the correct end-of-life pathway and ensure it is accessible to users: labelling alone is insufficient if the infrastructure does not exist.

可生物降解材料通过自然生物过程——被微生物分解——分解为水、矿物质和有机物。这种报废途径与传统合成塑料根本不同，后者在环境中持续存在数百年，碎裂成进入食物链和水道的微塑料。

为什么可生物降解材料在循环经济中受到青睐：

• 提供土壤养分 — 当可生物降解产品堆肥时，它们将有机物和矿物质归还土壤，支持农业生产力而不是耗尽它
• 减少垃圾填埋废物 — 完成其生物循环的可生物降解材料不会在垃圾填埋场积累，释放容量并减少填埋有机物质厌氧分解产生的甲烷
• 降低温室气体排放 — 与对持久性塑料进行焚烧或填埋相比，生物降解（尤其是好氧堆肥）在材料生命周期内产生的净温室气体排放更低
• 监管合规 — 许多司法管辖区正在对一次性塑料和不可生物降解包装引入禁令或征税；使用可生物降解替代品有助于企业避免罚款、遵守法规并进入有此要求的市场
• 封闭生物循环 — 在循环经济框架中，可生物降解材料参与生物循环：使用后安全地重新进入自然系统，而不需要工业回收或作为污染物持续存在

局限性：并非所有可生物降解材料都能在普通条件下分解。有些需要工业堆肥设施（特定温度、湿度和微生物条件），而这些设施可能在处置地点不存在。设计师必须指定正确的报废途径，并确保用户可以使用它——如果基础设施不存在，仅有标签是不够的。

Circular economy thinking requires designers to plan the entire product life cycle (including what happens to the product, its components, and its materials when the user is finished with it). Recovery and restoration form the closing loop of circular design:

• Reuse: the product is used again in its original form, by the same or a different user, without any manufacturing processing. Example: glass milk bottles collected, cleaned, and refilled. Requires standardised, durable packaging or product forms.
• Repair: individual components are replaced or fixed to return a product to working order, extending its useful life. Designers support repairability through accessible fixings, available spare parts, and standardised components. The Right to Repair movement advocates for legislation requiring manufacturers to provide spare parts and repair documentation.
• Recondition (refurbish): products are cleaned, tested, and restored to a like-new condition, often with replacement of worn components. Reconditioning typically requires more intervention than repair but less resource input than manufacturing new. Example: remanufactured printer cartridges, refurbished electronics.
• Recycling: materials are recovered and processed into raw material inputs for new production. To facilitate recycling, designers use the resin identification coding system (numbers 1–7 inside a triangle of chasing arrows): 1 PET, 2 HDPE, 3 PVC, 4 LDPE, 5 PP, 6 PS, 7 OTHER. Single-material components and clear labelling enable efficient sorting at recycling facilities, avoiding costly spectroscopic analysis. Mixing plastic types (e.g., a PET bottle with a PVC label) contaminates recycling streams.

Take-back legislation places legal responsibility on manufacturers to recover products at end of life. Examples include the EU Waste Electrical and Electronic Equipment (WEEE) Directive (requiring manufacturers to fund and organise collection and recycling of electronics) and extended producer responsibility (EPR) schemes for packaging. Take-back legislation creates an economic incentive for designers to design for disassembly and recyclability: the manufacturer pays for end-of-life handling, so reducing that cost requires designing products that are cheap to recover.

循环经济思维要求设计师规划整个产品生命周期——包括当用户不再使用产品、组件和材料时会发生什么。回收和恢复构成循环设计的封闭环路：

• 再利用 — 产品以原始形式再次使用，由相同或不同的用户使用，无需任何制造加工。例如：收集、清洗和重新装填的玻璃牛奶瓶。需要标准化、耐用的包装或产品形式。
• 修复 — 更换或修复个别组件，使产品恢复正常工作状态，延长其使用寿命。设计师通过易于接触的固定件、可获得的备件和标准化组件来支持可修复性。维修权运动倡导立法要求制造商提供备件和维修文档。
• 翻新 — 产品被清洁、测试并恢复到近乎全新的状态，通常更换磨损的组件。翻新通常比修复需要更多干预，但比生产新品需要更少的资源投入。例如：再制造墨盒、翻新电子产品。
• 回收 — 材料被回收并加工成新生产的原料。为了促进回收，设计师使用树脂识别码系统（追逐箭头三角形内的1-7数字）：1 PET、2 HDPE、3 PVC、4 LDPE、5 PP、6 PS、7 其他。单一材料组件和清晰标签使回收设施能够高效分类，避免昂贵的光谱分析。混合塑料类型（例如，带PVC标签的PET瓶）会污染回收流。

回收立法将产品报废时的回收法律责任置于制造商身上。例子包括欧盟废弃电气和电子设备（WEEE）指令（要求制造商资助和组织电子产品的收集和回收）以及包装的延伸生产者责任（EPR）计划。回收立法为设计师提供了为拆卸和可回收性设计的经济激励——制造商为报废处理付费，因此降低成本需要设计易于回收的产品。

Renewable energy sources are those that are naturally replenished on human timescales and do not deplete a finite stock:

• Solar: photovoltaic (PV) panels convert sunlight to electricity; solar thermal collectors heat water directly
• Wind: onshore and offshore wind turbines convert kinetic energy of moving air to electricity
• Hydroelectric: flowing or falling water drives turbines; includes run-of-river, dam reservoirs, and pumped-storage systems
• Geothermal: heat from the Earth's interior is used for electricity generation and direct heating
• Tidal and wave: kinetic and potential energy of ocean tides and waves; still emerging at commercial scale
• Biomass and bioenergy: organic material (wood, agricultural waste, purpose-grown energy crops) burned or converted to biogas; considered renewable only when sustainably sourced and managed

Why the circular economy depends on renewable energy: The circular economy's goal is to eliminate waste and pollution across the full system: not just the product, but the energy used to make, process, and recycle it. Fossil fuels are finite and produce greenhouse gas emissions that accumulate in the atmosphere as a form of irreversible waste. A circular economy powered by fossil fuels is not truly circular because:

• Fossil fuels are extracted and consumed: they cannot be "recovered and restored" like materials
• CO₂ emissions from combustion are a form of pollution that cannot be simply recycled back to fuel: they require massive carbon capture infrastructure to offset, which does not yet exist at scale
• Energy must flow through the system continuously; if that flow depletes finite stocks and generates persistent atmospheric pollution, the system cannot claim to be closed-loop

Renewable energy provides the continuous energy flow required by circular processes (recycling, remanufacturing, composting, take-back logistics) without depleting finite resources or generating waste that cannot be managed within the system.

可再生能源是那些在人类时间尺度上自然补充且不会消耗有限储量的能源：

• 太阳能 — 光伏（PV）板将阳光转化为电力；太阳能热收集器直接加热水
• 风能 — 陆上和海上风力涡轮机将流动空气的动能转化为电力
• 水电 — 流动或下落的水驱动涡轮机；包括径流式、水库大坝和抽水蓄能系统
• 地热 — 来自地球内部的热量用于发电和直接供热
• 潮汐和波浪 — 海洋潮汐和波浪的动能和势能；在商业规模上仍处于发展阶段
• 生物质和生物能源 — 有机材料（木材、农业废物、专门种植的能源作物）燃烧或转化为沼气；仅当可持续采购和管理时才被视为可再生

为什么循环经济依赖可再生能源：循环经济的目标是在整个系统中消除废物和污染——不仅是产品，还有用于制造、加工和回收产品的能源。化石燃料是有限的，会产生在大气中积累的温室气体排放，这是一种不可逆转的废物。以化石燃料为动力的循环经济并不是真正的循环，因为：

• 化石燃料被提取和消耗——它们不能像材料那样被"回收和恢复"
• 燃烧产生的CO₂排放是一种无法简单回收成燃料的污染——它们需要尚未大规模存在的大量碳捕获基础设施来抵消
• 能量必须持续流过系统；如果这种流动耗尽有限储量并产生无法在系统内管理的持久大气污染，则该系统无法声称是闭环的

可再生能源为循环过程（回收、再制造、堆肥、回收物流）提供所需的持续能量流，而不会消耗有限资源或产生无法在系统内管理的废物。