Opportunities and strategies for multigrade waste heat utilization in various industries: A recent review

Highlights: • Starting from the energy grade, 12 typical industries are divided into three categories. • Evaluate the application potential of waste heat recovery technology in industry. • Compare the difference between advanced and traditional technology, highlight its contribution. • The future research directions with great potential are put forward. Serious energy crises and ecological pollution have had negative impacts on all countries worldwide. These challenges are largely attributed to the production and operation of industries. Nevertheless, the advent of advanced waste heat recovery approaches has given rise to unprecedented opportunities and challenges in the current grave energy and environmental situation. The recovery and utilisation of waste-heat in various industries is an effective approach to improving economic benefits, conserving energy, and reducing emissions. In this review, 12 typical industries are preliminarily classified into three categories, according to the waste-energy grade. From the perspective of typical waste-heat sources, the waste heat recovery potentials of various technologies are analysed and discussed in terms of thermal performance, economic benefits, and environmental benefits. Subsequently, the development of a waste heat recovery approach is comprehensively reviewed, and the performance and structural configuration are summarised and scientifically compared. A detailed technical report is presented on the effective responses to pollutant emissions in various industries. Finally, the limitations in the current research and potential future directions are discussed. Through a comprehensive review of the recovery and utilisation of waste-heat in complex or large industries, this study provides constructive guidelines for researchers and enterprises engaged in related fields. Concurrently, its fills knowledge gaps by providing comprehensive information and the latest research results on the recovery and utilisation of waste-heat in various industries.