Refrigerator Optimization Heat Exchanger
Improving energy efficiency and reducing the cost of the appliance simultaneously is a continuing challenge for refrigerator manufacturers. While conventional system configuration is based on a single evaporator vapor compression cycle, there are several other system configurations that can offer benefits over it. For example, a dual evaporator (one evaporator for freshfood and one for freezer) offers several benefits such as increased efficiency, isolation of odors, and higher humidity levels in the freshfood compartment. Engineers typically use extensive experimentation to optimize the system. This approach takes significant time and resources. Although optimization studies exists for a conventional single evaporator cycle, studies for dual evaporator cycle optimization are limited. Most manufacturers do not explore complex architecture due to time consuming, labor intensive and expensive development procedures. This study presents experimental results obtained from a prototype dual evaporator refrigerator. Further, this study presents a physics-based model and a multi-objective optimization methodology that demonstrates how engineers can optimize a refrigeration system by considering multiple objectives simultaneously. The study presents example optimization results for simultaneously minimizing cost and maximizing performance within a specified design space. Optimization of the novel design uses a genetic algorithm-based optimizer in conjunction with a response surface based metamodel. Using optimization techniques, we can arrive at lowest cost design relatively quickly as shown in the analysis. More work needs to be done to validate optimized solutions as well as alternate methods to improve temperature control.