Abstract
Life cycle accessment (LCA) has been widely used to evaluate the environmental load associated with products, materials and services from cradle to grave. Most of the effort in LCA so far has been devoted to construct the inventory database because collecting the related data is tremendously time-consuming process. On the other hand, problems of LCA as a evaluation tool also has to be considered. Typical LCI methods, such as I/O analysis and process analysis, assume that the relationships between the input and output for each process are linear. In fact, most of the relationship between the input and output for processes do not satisfy the linearity and so the influence of the non-linearity on the result has to be investigated to evaluate more accurate environmental load. This paper formulates the nonlinear analysis in LCA to extend the normal linearity-based LCA. In the formulation, a method to express the nonlinearity in the general format is newly proposed. Next, a general system for the evaluation of environmental load is developed using this formulation. It is shown that object-oriented approach is effective for the development. Using the developed system, influence of non-linearity on environmental load and the derived problems will be investigated. Finally, an effective method to modify nonlinear data, which is supposed to become important in the future, will be proposed.
