Optimal planning of a cascade-type multistage refrigeration system for a beverage plant

An optimal planning method is presented for a cascade-type multistage refri geration system. Heat exchange areas of evaporator, condenser, and beverage cooler are determined optimally so as to minimize the annual total cost an d input energy consumption subject to constraints concerning annual equipme nt operation. This problem is considered as a multiobjective optimization o ne, and a discrete set of Pareto optimal solutions is derived numerically b y a weighting method. Through a numerical study, it is investigated how the heat exchange areas influence the long-term economics and energy conservat ion. Cascade-type multistage refrigeration systems are compared with single -stage systems.