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At the front end of the value chain, circular design ensures that products are developed and manufactured with circularity in mind-enabling them to re-enter material loops after their use phase through reuse, refurbishment, or recycling.

The sector- or industry-specific selection of appropriate circular design principles is furthermore influenced by the fundamental motivations guiding a company’s orientation towards the circular economy. The decision to adopt or reject a particular circular design principle is therefore always case- and context-dependent, taking into account any applicable (voluntary or legally mandated) design standards. For example, if a company’s primary motive for pursuing circularity is economic efficiency and profitability, and there is no regulatory pressure, only those design principles that contribute directly to achieving financial goals will be applied. In such cases, design principles addressing additional objectives, such as environmental protection, will only be considered if they serve as means to the end of profit generation-i.e., if they ultimately lead to cost reductions, increased revenues, or enhanced brand reputation. The latter aspect becomes significant only if consumer purchasing behavior rewards it.

Resource efficiency

Resource efficiency, as a central overarching design principle of the circular economy, involves the development of products and processing methods aimed at reducing material and energy consumption throughout the entire lifecycle while maintaining or enhancing functionality and economic value (input-output optimization). Resource efficiency helps to address ecological scarcity challenges and generates economic benefits through the reduction of absolute raw material costs and increased material circularity. Resource-efficient design thus serves as a bridge between ecological and economic interests. It requires an integrative approach along the entire value chain-from raw material extraction through manufacturing, usage, and further recovery options via the creation of material loops-and calls for interdisciplinary collaboration among design, engineering, environmental, and economic sciences. With this systemic approach, which places the optimization of material use at the core of decision-making, resource-efficient design inherently encompasses all subordinate circular design principles.

Durability

Durability is a central overarching design principle of the circular economy. It aims to maximize product lifespan through design measures and the selection of appropriate raw materials. This also includes material research and innovation. As with all design principles subordinate to durability, it is essential to consider the entire circular value chain-meaning that at the outset, forward-looking concepts for material reuse and repurposing are integrated, and at the end of the product’s life, creative solutions for further utilization within the usage cycle are sought.
The consistent implementation of durable product design can be challenging within the biological cycle, especially for rapidly degradable natural materials, but this is mitigated by their regenerability (assuming favorable life cycle assessments).

Timeless aesthetics

Timeless aesthetics refers to product design that maintains its visual value and functionality over extended periods, remaining durable, relevant, and appealing regardless of current trends in materiality, texture, form, appearance, and overall attractiveness. Items regarded as “timelessly aesthetic” are often characterized by simplicity, clarity, harmony, classicism, elegance, and refined form, embodying a design quality that is perceived and appreciated as beautiful across different eras. Design classics serve as prime examples of this principle-products that consistently appear stylish and contemporary. Circular design should particularly embrace the principle of timeless aesthetics to ensure that products remain attractive to subsequent users independently of fleeting fashion trends.

Emotional attachment

Emotional attachment refers to the appreciative, identity-forming, and familiar relationship between user and product that goes beyond mere functionality. This attachment enhances the user experience and brand loyalty. It can be fostered, for example, through co-creation and participatory, iterative feedback loops, whereby user ideas and demands are incorporated into the product design. This is also relevant at the end of the value chain when it comes to upcycling solutions that consider the design and symbolism of the product, addressing user preferences and even enabling customization during manufacturing. The underlying concept is the emotional design approach, which posits that objects continue to be used beyond their conventional lifespan due to factors such as brand image, cultural value attribution, personal history, or other associated characteristics. Examples include a well-worn favorite T-shirt, a particular brand, or a cherished inherited wardrobe. For objects to which a user feels emotionally connected, openness toward additional material loops, such as restoration, tends to be significantly stronger.

Qualitative value

Qualitative value is determined by the quality of workmanship and the raw materials used. This design principle is a prerequisite for the technical durability of a product and simultaneously guarantees its perceived value. When a product is designed and manufactured to high quality standards, it typically (depending on the producer’s motivation) helps prevent planned obsolescence. At the very least, natural obsolescence is slowed down, as the product is more robust and thus more resistant to external mechanical or chemical influences. Due to its durability-resistance to wear and aging-it is also less prone to requiring repairs. The so-called “throwaway design” (e.g., fast fashion, fast furniture) is thus counteracted. Even if the user no longer needs the product, its qualitative value makes it more attractive for subsequent use, for example through looped reuse or as a material basis for upcycling variants.

Pure material

Pure material as a circular design principle refers to the use of mono-materials in product design – even when combining multiple product components. This facilitates later separation into single-type material fractions and thereby supports subsequent recovery processes within all material loops. The use of pure materials is a critical forward-thinking measure, especially in light of either non-existent or highly complex technological separation processes. It often represents a prerequisite for enabling cycling strategies in the first place and avoiding incineration after end-of-use. Beyond the circular reuse of materials, employing mono-materials in the initial production phase can already yield efficiency gains—provided that a well-considered design concept is in place which, in terms of functionality and other product characteristics, matches or even surpasses mixed-material solutions. Adopting the design principle of pure material also contributes to an overall reduction in material diversity.

Disassemblability

Disassemblability as a circular design principle emphasizes the importance of designing products for easy dismantling and material separability. When a product is constructed in a way that allows its components to be easily separated, maintenance and repair of individual parts are facilitated. This enhances the potential for refurbishment and reuse. For instance, the incorporation of a used component into a new product with the same function (remanufacturing) or a different function (repurposing) both fall under the upcycling loop. Moreover, complete disassembly of a product into its constituent materials opens up further options for reuse, either as a direct raw material source or within the downcycling loop (improved recyclability). Thus, separable materials are a crucial prerequisite for implementing circularity, as is clearly demonstrated in cases where disassemblability has not been considered as a design principle.
For example, in textile cycling, separating polyester from blends with cotton or other fibers is technically challenging and costly. Another problematic separation process involves composite materials such as plastic-coated, synthetically bonded wood fiberboards in furniture manufacturing.

Modularity

Modularity refers to the design of products as assemblable units whose components can be independently manufactured, replaced, repaired, upgraded, or reused. This principle promotes the extension of product lifespan by enabling easy repair of individual parts as well as upgrades and expansions through retrofitting and new combinations of components, potentially leading to multifunctionality. This adaptability and flexibility help prevent premature obsolescence. Furthermore, a modular product design facilitates the reuse of components in different contexts and simplifies their reintegration into technological or biological cycles.

Zero Waste

The emphasis of this meta-concept lies on the complete elimination of waste throughout the entire product lifecycle. The goal is to achieve a fully circular economy. Accordingly, products are designed so that all utilized resources are either biodegradable or fully recoverable into existing production cycles. Under this premise, the use of non-renewable raw materials is essentially excluded, permitted only if it is guaranteed in advance that no materials are lost as unused resources. This means that only product designs that ensure absolutely closed loops with one hundred percent resource retention within the system are acceptable.

Bionic

The meta-concept of biomimicry involves developing technical solutions by abstracting structures and functional principles from nature and transferring them into product design. The evolutionarily optimized strategies of biological systems, honed over millions of years, serve as models for resource- and energy-efficient, robust, and adaptable design. In the context of the circular economy, biomimicry contributes to reducing material use and energy consumption through circular process optimization. However, it is not an explicit objective of biomimetic solutions to dissolve linear production patterns into fully closed-loop systems or to achieve a reduction in material throughput in the sense of pronounced sustainability. To achieve this, biomimetic design would need to be integrated with the value parameters of all circular design principles or other meta-concepts of circular design.

Ecodesign

The meta-concept of eco-design (also referred to as ecological design or ecodesign) denotes a holistic design approach in which ecological criteria are systematically integrated into the entire product development process. The objective is to minimize the environmental impact of a product throughout its entire lifecycle-from raw material extraction through production and use to disposal or recycling. This approach incorporates all circular design principles and additionally involves further value criteria aimed explicitly at improving product life cycle assessments and thereby conserving resources. Examples include the rigorous avoidance of environmentally hazardous and health-risk materials or product finishes. Furthermore, the meta-concept of eco-design encompasses the use of local resources (local production) and the preferential use of biologically rapidly degradable raw materials.

Sustainable Design

The meta-concept of sustainable design encompasses and extends the approaches of eco-design. Depending on the degree of the underlying sustainability commitment and the associated ethical orientation, this meta-concept can extend to postulates of production and consumption reduction, reflecting a highly ambitious circular economy that emphasizes the deceleration of energy and material flows. Moreover, sustainable design incorporates the social dimension in the structuring of value chains, including approaches such as inclusive design. Accordingly, this meta-concept embraces all circular design principles and, through the integration of comprehensive value parameters, represents a design approach with the broadest spectrum of design requirements.