Approximate Life Cycle Assessment via Case-Based Reasoning for Eco-Design

Abstract

"Life cycle assessment (LCA) is a fundamental tool used in eco-design. However, it can be costly and resource intensive. We take steps toward the automation of the inventory and impact analyses stages of LCA via the proposal and development of a case-based reasoning (CBR) procedure to estimate the ecological effects of a product. The case memory in CBR, which contains representations and ecological effects of known products, is organized using an extension of the function-behavior-structure (FBS) representation for products. The extension includes ecological characteristics and values. We develop similarity metrics to measure the distance between cases in the case memory and the new product. The k-medoids algorithm is used to cluster the case memory, our metrics enable cluster retrieval and case selection, and multiple linear regression analysis is employed for adaptation. Using a database of 100 fans, we test the accuracy of the proposed approach on a cross flow fan not in the database. The method gives ecological effect estimates within 3% of the true values when there are similar fans in the retrieved cluster and about 7% when the retrieved cluster does not contain similar fans.Note to Practitioners-While life cycle assessment (LCA) is an essential component of modern eco-design practices, it is cost and resource intensive. We propose and develop a case-based reasoning (CBR) procedure that allows swift and accurate estimates of the ecological effects of a new product. The estimated ecological effects are within about 5% of the true ecological values for the new product. Such accuracy is obtained by having a relatively large database of existing products with LCA data and using an intermediate level of detail when describing the products. As such, the LCA via CBR is most applicable to products which are developed as modifications of existing ones (e.g., cell phones, automobiles). It is hoped that the proposed method can be extended to allow for LCA estimates at many levels of product detail."