Circularity Indicator Calculation Tool, A comprehensive method and metric for measuring thecircularity of a product

Abstract

With the growing interest in circular economy within the industry there is a need for a way to measure the circularity of a product. This circularity metric needs to, for the sake of fair comparison, stay consistent over time and should therefore have a scientific base. The intended area of use of the metric described in this thesis is during the concept stage of product development to assist in making design decisions of what actions to take to make products more circular based on calculations instead of guesses. Departing from these criteria, a tool was constructed, based on a methodology suggested by Linder et. al. (2017) and modified to work with cumulative energy demand (CED) instead of monetary value. This circularity indicator is calculated as the ratio between the amount of CED saved from using recirculated materials and components and the sum of the CED of all virgin materials, components and processes and the CED saved from using recirculated materials and components of the product. In addition to the tool a dataset was constructed to supply data for a small number of commonly used materials and processes to use when product specific data for the product is unknown.The tool was validated against a number of cases for a coffee brewer from 3Temp where a circularity indicator was calculated and compared. The validation showed that making the calculations are as useful by themselves as the actual results are as it gives insight into what parts of a product accounts for the majority of the environmental impact, as well as the realization that the closer to a whole product the recirculation is made i.e. reusing the product instead of reusing components or recycling materials, the better the circularity indicator becomes.