9.1 Introduction and synopsis
Audits like those of Chapter 7 point the finger, directing attention to the life phase that is of most ecoconcern. If you point fingers, you invite the response: what do you propose to do about it? That means moving from auditing and assessment to selection—from the top part of the strategy of Figure 3.11 to the bottom.
Chapter 8 introduced the methods. Here we illustrate their use with case studies. The first two are simple, showing how selection methods work. Those that follow get progressively more complex, leading up to the last two, which deal with heating and cooling and with transport, two of the biggest sinks of energy and sources of emissions in industrialized society.
Super lightweight vehicles: shell ecomarathon contester, Cal Poly Supermilage team vehicle, “Microjoule" by the students of the Lycee La Joliverie, France, and “Pivo2" electric car by Nissan. All have shell bodies made from materials chosen for stiffness and strength at minimum mass.
Before starting, there’s something to bear in mind. There are no simple, single-answer solutions to environmental questions. Material substitution guided by eco-objectives is one way forward, but it is not the only one. It might sometimes be better to abandon one way of doing things (the IC engine vehicle, for example) and replacing it with another (fuel cell or electric power, perhaps). So, though change of material is one option, another is change of concept. And of course there is a third: change of lifestyle (no vehicle at all).
This book is about materials so, in Chapters 1 through 8, we stuck with them as the central theme. In this and the next two chapters we venture a little outside this envelope.