Innovation in energy analysis: development of GALGEM - general approach to low grade energy management

Reducing industrial low-grade heat generation and waste can lead to improved energy efficiency, decreased environmental emissions, and reduced fuel costs. However, it is an area that is recognised as being underexploited. Many studies have been carried out, which have developed methodologies and techniques for the reduction and reuse of the waste heat. Techniques are typically specific to a process or industry platform. Additionally, success levels of heat recovery and reuse projects can be heavily dependent on the prior knowledge and experience of the practitioner. This thesis shows the development of a new methodology called GALGEM (General Approach to Low Grade Energy Management), which combines existing Process Integration techniques with second law of Thermodynamics, together with analysis and heuristic rules to give a general guideline for energy management. The specific focus is on low-grade waste heat. GALGEM is based on the solid foundation of existing techniques and best practice. It guides practitioners through the decision-making process in order to exclude the less effective solutions, thus reducing reliance on tacit knowledge and expertise for the predetermination of success. GALGEM is designed to be applicable across all sectors and industrial processes. The technique was applied and developed through three diverse industrial case studies: an alumina production facility; a large international semiconductor manufacturing plant; and a small food processing plant. The results of the case studies, which highlight direct, indirect and combined heat exchange opportunities for waste heat recovery, are presented. Opportunities with a 15.2% resultant fuel saving were identified in the semiconductor manufacturing plant, while opportunities with a 30% resultant fuel saving were identified in the food processing plant. The novelty of GALGEM is the simplicity and general applicability of the approach, which is achieved without losing thermodynamic integrity. The GALGEM method offers a technique that can be successfully used in its current form, and offers a platform for further work and studies.