Professor Jerry Connor of the Civil Engineering Department at MIT gave a series of lectures at WIT on Design for Sustainability.
Sustainability, Jerry recalled “means that the needs of the present generation are met without comparing the ability of future generations to meet their own needs” (Brundtland Report, 1987). The concept has two important aspects, ie social, to meet human needs and ecological, to preserve the environment.
Sustainable design aims to produce objects using renewable resources and which, in operation, deplete only renewable resources.
The objectives of sustainability are:
- Eliminate contributions that increase substance concentrations from the earth’s crust.
- Reduction of material flows (increase resources productivity and produce less waste).
- Exchange products and processes.
There is no doubt, in Jerry’s opinion, that we need to eliminate our present impact on the environment and make more efficient use of natural resources and land. More caution in the modification of nature should also be exercised. The human needs in society worldwide ought to be faced, avoiding problems such as ecological pollution in developing parts of the world.
In engineering terms, engineers need to make more use of Life Cycle Assessment (LCA) to determine the effect of the products on the environment, looking at them from “cradle to grave”.
LCA also provides useful information for decision making for processes with environmental consequences. It is a quantitative tool, based on scientific data.
LCA may also involve evolution of problem shifting, such as evaluating electric cars using diesel or gas powered engines. It also should point out if the waste is shifted from region to region or from country to country. Another aspect of LCA is the possibility of recycling contaminated material into another product. Typical examples of this are rubber tyres used in motoring construction or flyash in concrete.
LCA allows the designer to produce not only Impact Assessments but also Improvement Assessment with which one can evaluate opportunities for improvement.
Jerry Connor explained how to produce a process flow matrix where the rows relate to flow of variables and the columns to the different processes involved. This matrix is usually divided into 2 parts, the first rows representing the economic effect and the others the environmental effect. The analysis usually produces a rectangular matrix which can be overdetermined (more economic flows than processes) or underdefined (more processes than economic flows).
Overdetermined systems can be solved simply using least squares but another strategy is to add more processes to be able to invert a square matrix. This addition in practice may result in a new idea such as power plant heat being used for another application instead of being dissipated, which results in more economic processes, having less harmful effect on the environment as well as making economic sense.
Impact Assessment issues are of different types and scales, ie:
- Climate change and resulting Global warming
- Acidification affecting vegetation
- Toxidity harmful to humans
- Resources depletion
The scientific challenge now is how to identify measures for the different effects in order to quantify the problems. This has given rise to considerable work on indicators, which are measures relevant to each category.
The research is now continuing and Jerry’s Research Group at MIT are now fully committed to Sustainable Design.
Wessex Institute