The relative exergy-destroyed array: A new tool for control structure design

Due to increasing energy demands, energy crises and strict environmental regulations, the eco‐efficiency of all industrial processes and plants has become vitally important. Control loop configuration or control system structure determination is a major and vitally important activity in the complex task of process control because a poorly structured control strategy can lose much energy from the process or plant when implemented. To save this loss of energy due to a poorly structured control strategy, engineers need to find a way to integrate control loop configuration and measurements of eco‐efficiency. In this paper, we present the relative exergy‐destroyed array (REDA), a new tool to measure the relative eco‐efficiency of a process. The REDA is a means to compare the eco‐efficiency of multi‐input multi‐output processes for different combinations of control structures. Based on steady state information, it is a simple tool for comparing eco‐efficiency. The results obtained from the REDA are interpreted and explained with the help of case studies involving a whole monochlorobenzene (MCB) plant and a heat exchanger network (HEN). The REDA may help guide the process designer to quickly find a control design with low operating costs and high eco‐efficiency.