An Open-Source Framework for Pinch-Based Heat Exchanger Network Optimization: Application to a Dairy Processing Facility

Pinch-based process integration is a well-established approach for improving industrial energy efficiency by systematically maximising internal heat recovery and minimising external utility consumption. However, medium-scale food processing facilities remain comparatively less investigated despite their significant heat recovery potential. Food manufacturing requires many process stages, including pasteurisation, sterilisation and drying, which involve heat transfer between intermediate and/or final products and heating/cooling media. Thus, the design and optimisation of heat exchanger networks (HENs) is essential to minimise external thermal energy requirements and promote the effective reuse of waste heat. This paper proposes a structured, rule-based and open-source synthesis framework for designing or retrofitting industrial HENs based on pinch analysis. The model is applied to a real dairy manufacturing process for cream production to determine the extent of energy savings from HEN retrofitting and to assess the potential technical, economic and environmental benefits. Under maximum energy recovery conditions (ΔTmin equal to the baseline network value), the redesigned heat exchanger network reduces the demand for hot and cold utilities by 48.5% and 44.9%, respectively, compared to the baseline configuration. A preliminary techno-economic assessment indicates simple payback periods between approximately 0.5 and 2 years under base-case cost assumptions, remaining below 4 years across a broad range of energy prices, investment costs and utilization factors.