A Method for Online Steady State Energy Minimization with Application to Refrigeration Systems

Energy efficiency of refrigeration systems has gradually been improved with the help of control schemes utilizing the more flexible components; the efficiency is though yet far from optimal. The flexibility initiates a higher degree of freedom in choosing the operating set points while obtaining the required cooling capacity. This paper proposes an approach which utilizes this newly gained degree of freedom to drive the system towards the energy optimal set-point while keeping up the cooling capacity. The focus of this paper is on refrigeration system however the generality of the proposed method thus applies to a broader range of process systems where the lower level set-points (in the control hierarchy) can be chosen within a degree of freedom allowing an optimization of a steady state performance index