A hierarchical framework for concurrent assessment of energy and water efficiency in manufacturing systems

Efficient energy and water use has become a matter for increasing concern to industry due to rising energy prices, decreased availability of quality water and the environmental concerns of governments and the general public. For an organisation to enhance its energy and water efficiency, it must first determine where, when and how much energy and water are needed by different pieces of equipment in its manufacturing system. This paper presents a hierarchical framework that models the energy and water consumed in a manufacturing system according to the structure of facilities. A state-based technique was used to develop a generic module for a single machine tool and customized modules for steam generation and compressed air systems. Production in a pharmaceutical company was simulated after which a simultaneous analysis of energy and water efficiency was carried out. It was shown that a reduction of 6.42% and 1.97% in the consumption of energy and total water per litre of product is achievable by selecting different production parameters. This also revealed that indirect water consumption due to raw materials and primary energy may have a significant impact on any assessment and should also be considered in conjunction with the direct water consumption. (C) 2016 Elsevier Ltd. All rights reserved.