A new exergy-based model predictive control methodology for energy assessment and control

The paper proposes a new methodology based on integration of an exergy-auditing analysis with a model predictive control (MPC) scheme. The primary advantage of the methodology is that exergy analysis provides rich information to recognize processes that consume the major portion of energy. The proposed exergy-based MPC method thus is capable of incorporating the desired set-point values in conjunction with the corresponding operational constraints, being dictated by the exergy analysis, in design procedure of MPC. The proposed control scheme guides the system toward the desired set-points in a multi-input, multi-output (MIMO) configuration enhancement of the energy efficiency and prevention of loss of energy due to possible disturbances. The proposed method is comparatively implemented on an air separation unit as the benchmark case study in which a compressor – which is very common in gas industry – is identified as the main part with the major wasting energy. Variety of experiments was conducted to check the compressor under different disturbances. By 22 percent energy saving in the steady-state condition, the results clearly demonstrated superiority of the proposed methodology compared to the other energy-based MPC approaches.