"Thermal penalty factors" accounting for site topological characteristics in pinch design of Heat Exchanger Networks

Pinch analysis allows to determine targets and solutions for minimum energy requirements in process plants, basing on innovative tools like composite curves and table problem formulation, which ultimately allow generating an optimized heat exchanger network design. On another hand, this technique does not account directly for a number of factors which could play a primary role for the practical feasibility of the network. What if, for instance, once identified an optimal lay-out, we realize that some matches are hardly feasible in practice? Could we adapt the conventional pinch approach to keep into account site topological features since the preliminary design phase? In this paper the authors attempt answering these questions by introducing “Thermal Penalty Factors”, to be calculated for any match by accounting for the capital cost needed to realize it. Appropriate expressions for these penalty factors (in kW) are firstly obtained; successively, these factors are integrated into the composite curves, so as to enable the analyst to account for them since the design phase. A simple case study is adopted to highlight the potential of thermal penalty factors in contributing to achieve more reliable targets.