Towards a Circular Economy in the Built Environment: An Integral Design Framework for Circular Building Components

Abstract

The building sector consumes 40% of resources globally, produces 40% of global waste and 33% of emissions. The Circular Economy (CE) proposes an alternative to the current linear economy by decoupling economic growth from resource consumption. In a circular built environment, resource depletion and waste generation are minimised, and materials are circulated at their highest utility and value. Buildings consist of many components such as kitchens and facades which could be replaced by ‘circular components’ during maintenance and renovation, thus allowing a bottom-up implementation of the CE within the built environment. To support industry in the development of such components, an integral design framework is needed, including technical, supply chain and business specifications. Current frameworks do not suffice, as they are either fragmented (addressing only the business model or technical design) or are not developed for the building sector. In this paper, we present a framework to support industry in the integral design of circular components. The framework was developed in three stages. First, through a literature review, existing circular design frameworks were identified. Second, by combining and specifying these frameworks, the Circular Building Components Generator (CBC-Generator) was developed. Finally, the CBC-generator was tested in the development of an exemplary component: The Circular Kitchen (CIK). The CBC-Generator is a three-tiered design tool, consisting of a technical, industrial and business model generator. The generators are ‘parameter based’: consisting of a design template and option-matrix. By filling the templates through systematically ‘mixing and matching’ the options of each parameter, different variants for circular components can be formed. Employing the CBC-generator, TU Delft, AMS-institute, housing associations and industry partners developed the CIK. The CIK consists of a docking station in which kitchen modules can be plugged in and out. The modules consist of a frame to which ‘function modules’ (appliances) and ‘style packages’ (front, countertop) can be easily attached, using click-on connections. The professional side of the business model applies a purchase with take-back model including circular KPI’s and service subscriptions. A dealer offers extra kitchen modules and style packages to tenants through a variety of financial arrangements that motivate returning the product after use, including lease and sale-with-deposit options. After use, the kitchen producer and dealer ‘re-loop’ the docking station, kitchen modules, parts and materials in a ‘Return factory’ and local ‘Return streets’. The CBC-generator successfully supports the integral design of circular components: (1) it provides all the design parameters which should be considered; (2) it gives various design options per parameter; (3) the generator supports systematic synthesis of design options to a cohesive and comprehensive circular design. Further development can contribute to establishing causal links between ‘parameter-options’, and identification of ‘the most circular variant’ in terms of both environmental burden and Total Costs of Ownership/Use.