Simplified physical system theory model of a closed chain production system

Abstract

A more comprehensive yet simple approach to modelling and analysis of material and energy flow in production processes is proposed. The modelling approach is based on the principles and concepts of physical system theory (PST) in a simplified framework. The flow of mass and energy are considered as ‘through’ variables, whereas unit enerey costs are considered as ‘across’ variables. The ‘through’ and ‘across’ variables are governed by the laws of continuity and compatibility, respectively. An overview of the closed chain model by Hirata and Fukao (1978) is given and some observations are outlined calling for a modified framework. In the PST framework generalized models of an ideal closed chain system and a closed chain system with losses are developed. These models are illustrated by a three stage production system and the results are compared with those of Hirata and Fukao (1978).