Study on approaches of extending refrigeration capacity range of parallel power/refrigeration cogeneration Kalina cycle system

•Air conditioning refrigeration achieves by guiding refrigerant vapor to mid-absorber.•Parallel PR cogeneration KC matches heat source well in cascade boiler and generator.•Leading generator dilute solution to low-pressure absorber has better performance.•Performances are improved by optimizing solution concentrations and boiler superheat.•Refrigeration/power ratio extends to 1.192 with boiler bubble point Δt rises to 60 K. A parallel power/refrigeration cogeneration Kalina cycle (PPR-KC) system with adjustable refrigeration/power ratio that developed on the basis of the triple-pressure Kalina cycle system was analyzed. The PPR-KC system can produce refrigeration with temperature ranging in either air conditioning or ice making by switching the exhaust refrigerant vapor to the mid-pressure absorber or to the low-pressure one. The influences of the dilute solution from generator to the destination of either mid-pressure absorber (plan A) or low-pressure absorber (plan B) via recuperators on the performances of the PPR-KC system for air conditioning were investigated. The results show that the PPR-KC system matches well the heat source in cascade arranged boiler and generator thus showing excellent thermal performance by optimizing the solution concentrations, boiler superheat and other parameters. Under the given temperatures of heat source 400°C and cooling water 30°C respectively, the variation trends of the cycle parameters and performances of both plan A and plan B are presented. The power recovery efficiency of plan B is about 1.6% higher than that of plan A. When boiler bubble point temperature difference increases from 20 K to 60 K the refrigeration/power ratio of plan B climbs from 0.475 to 1.192.