Date of Award

2019

Degree Type

Dissertation

Degree Name

Doctor of Philosophy in Industrial and Systems Engineering

Department

Mechanical, Industrial and Systems Engineering

First Advisor

Manbir S. Sodhi

Abstract

In this dissertation study, the concept of an energy shadow, which represents all the work done by the interacting systems back to the earth-based inputs needed to produce a product, is used as a metric to investigate the development of a real-time, geometry-based software tool to assist design engineers in evaluating the environmental impact of manufacturing. A literature review of the energy metrics of consumed energy, exergy, and emergy was conducted to evaluate which may best serve as the thermodynamic framework for representing an energy shadow. Following the comparison and evaluation of the possible metrics emergy was selected as it best covers the entire energy shadow of a product. The framework was developed for manufacturing using emergy accounting as an analog to cost. Modular emergy models were generated as analogues to the major manufacturing cost accounting areas, and the framework was applied to an example assembly using data from a design for manufacturing (DFM) cost analysis as input. This framework greatly expanded the detail and coverage of existing emergy models regarding manufacturing areas. The models in the framework were implemented as a prototype extension in a commercially available manufacturing costing software that provides cost estimates based on 3D CAD files. Sensitivity analyses of the model were conducted based on changing input values for emergy and varying the CAD geometry, which identified areas for model refinement and characterized the influence of the design parameters. The software extension was tested with a group of 19 engineering students including both graduates and undergraduates to understand if the use of emergy as a sustainability metric enabled better ranking of a set of design alternatives. It was found that performance on the ranking exercise improved in a statistically significant manner after exposure to the concept of emergy and the software extension. The participants were able to constructively provide feedback for further improvement on the best designs, despite limited exposure to the newly introduced concept of emergy.

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