Abstract
A matrix method has been applied to investigate environmental burdens on a complex production system with some
feedback flows. Process activities in the system should be consistently calculated by simultaneous equations of an inverse matrix. However, there are two theoretical problems to be solved for using a matrix method. Firstly, the matrix between processes and materials in a production system should be a regular matrix. Secondly, environmental burdens of a system are analyzed only for processes but not for materials by the conventional matrix method. The study aims to develop a new method which can solve the problems. We propose a new method to analyze process activities of a production system with feedback material flows. In the method the number of processes and materials in a production system is changed to construct a regular matrix. An analytical method is also developed to estimate environmental burdens of material products in the system. The two proposed methods are applied to a case study which estimates process activities and CO2 emissions. The results indicate that environmental burdens of the complex system are consistently investigated by the new method. In addition, the results of process activities are compared with the conventional method to confirm the validity of our method.
