State-of-the-art review of heat integrated water allocation network synthesis.

• Techniques for heat integrated water allocation network synthesis are reviewed. • Pinch analysis, mathematical programming, and hybrid approaches are compared. • The research progress is highlighted through a case study. • Significant contributions are emphasized and future directions are provided. Heat integrated water allocation networks (HIWANs) were developed to conserve energy and water in the process industry using heat exchangers, and in some cases with water regeneration units. This paper addresses the challenges in optimizing HIWANs posed by the interactions between the water, energy, regeneration units, and heat exchangers. The optimization strategies are classified based on the adopted ideologies, and the progress in each category is discussed. A case study is examined to highlight the effect of adopting various strategies on the optimal solution. It is observed that the research progresses from the conservation of resources and operating costs to the inclusion of investment costs. More recent papers include studies that capture the trade-offs between freshwater, regeneration, utilities, and heat exchangers. The analysis of publications in different conferences and peer-reviewed journals is performed. After a detailed review of the existing work, some areas of improvement and new research perspectives are identified. [ABSTRACT FROM AUTHOR]