Unlike older approaches, modern refrigerator designers’ major goal is to maintain a uniform temperature across all compartements. Of course, such temperature can vary within a very restricted range, as it must be appropriate for food conservation. At the same time, it is becoming more and more important to reduce energy consumption, and to conform to international standards (such as the class A parameters for electric appliances). Achieving these goals would be fairly easy if one could use very large evaporators, and thick insulation in the refrigerator walls. Unfortunately, this is not feasable, as the refrigerator would then become large, heavy, and expensive, all undesireable features for a mass-market product. The challenge then is that of finding the ideal match between insulator thickness and properties, and the size, shape and location of the evaporator, so that a good trade-off is found.
To address this problem for its new Oz refrigerator, Electrolux-Zanussi decided to turn to modeFRONTIER. The problem was parametrized by specifying the thickness of the insulator panels in different compartements, the overall properties of the insulator, and variables determining the size and position of the evaporator. The goals were the maximization of the temperature uniformity, the minimization of the heat ux through the refrigerator, and the minimization of the evaporator area. Natural convection heat transfer within and through the fridge was studied using STAR-CD, running on an SGI Origin2000. Using the MOGA algorithm, Zanussi was able to nd the Pareto design, with a set of extreme designs, and many intermediate ones. Using the decision making tool integrated in modeFRONTIER to rank-order the designs based on their preferences, they were then able to nd the design that best met their requirements.