This paper gives general information about multi-objective, axiomatic and robust design approaches and considersasolution model of nonlinear multi-objective optimization problem based on applyinganew robust design approach. Both axiomatic and robust design approaches were used complementarily inacase study with distinct multi-objectives. In this case study, the main target was achieving each objective optimum to minimize the mass and the shear stress ofaspring by integrating robustness and durability at the design stage due to trade off between objectives. This spring problem was examined using the independence axiom of the axiomatic design methodology. Also, semangularity and reangularity concepts were used and design matrices were formed to find coupled and decoupled solutions. It was observed that there were some acceptable design parameter values for which the design became decoupled. Graphical and numerical results were checked to see if they were compatible with each other. Finally, this decoupled design was given appropriate tolerances by using robust design method. This way,arobust and durable spring was designed which would satisfy the given specifications with minimum cost in the existing literature from the view point of axiomatic design approach.
Optimum design for storage type Electric Water Heaters (EWHs) was analyzed for energy conservation and maximum hot water output. Single and dual tank EWHs were compared with each other. For each comparison, data were gathered for tank volumes and power ratings ranging 100-400land 1-4 k Wrespectively. Different dual tank EWHs were designed with different control mechanisms to find which one had the optimum outcome. For these comparisons, dual tank EWHs in which the upper part of the tanks had 25%of the total volume and 75%of the total power rating were used. Afive day usage period of an EWHinatypical household was simulated on SIMULINK. To minimize this energy loss, transient analysis on FLUENTwas performed to see how long it took for the outlet water temperature. In these simulations, single and dual tank EWHs with different control mechanisms were compared with each other to find the design with minimum energy consumption and maximum hot water output. From these results the most efficient control system cost analysis was determined for minimum operating cost and minimum carbon footprint through optimized control strategies.