Simultaneous water and energy conservation through graphical and mathematical programming: a case study for float glass industry

•The existing water energy network (WEN) of a float glass plant studied carefully and based on that, revised WENs developed.•These WENs based on a combination of graphical, heuristics and mathematical programming developed by different researchers.•There will be a reduction in consumption of makeup water in tune of 15–65%.•Savings in energy will be around 34–52%. There will be an overall reduction of 13–35% in terms of cost.

This paper represents a systematic approach for the synthesis of re-circulating cooling water systems consisting of a cooler network and a cooling tower network of a float glass process industry. A unique combination of graphical and mathematical programming technique of water pinch was used to revamp the existing water and energy network. Total nine different types of methods including Aspen Water used to develop nine different integrated water and energy networks with a payback period of around 8–11 months which clearly reflects that all the WENs are techno-commercially viable. There will be a reduction in consumption of makeup water in tune of 15–65% and savings in energy will be around 34–52%. There will be an overall reduction of 13–35% in terms of cost.