A Survey of Physical Flow Models

Different types of models have been developed to analyse the physical flows of materials and energy. These include material flow analysis, physical input-output analysis and life-cycle assessment. This chapter presents an overview of these models with their different data needs, aggregation levels, purposes and applications. The strengths and weaknesses of the models as well as their similarities and differences are discussed. For the comparison of the different methods, their particular characteristics are examined. A typology of these characteristics precedes the description and comparison of the methods. This comparison will support the selection process of choosing appropriate methods for specific problems. Finally, the relation between physical flow models and M-P chain analysis is considered.