Optimization method for lifecycle cost in the conceptual design of products having variable energy consumption

This research focuses on quantitative analysis techniques for optimization of conceptual designs for products where life-cycle considerations are crucial. A product for which energy saving is practically mandatory, such as a major home appliance, was chosen, and the proposed procedure for minimizing the total cost through the product's lifecycle focuses especially on the use and maintenance stages. A multiobjective optimization problem is developed to minimize two evaluative characteristics, the manufacturing cost of the product (I), and the sum of the energy and maintenance costs of the product over an assumed period of time (II), treating the longevity of specified portions of the product and energy consumption rate as design variables. The optimization simulation was carried out for a numerical example based on this model, and a Pareto optimum solution for costs (I) and (II) was obtained. Using this Pareto optimum solution, we analyzed the optimum values of design variables and clarified quantitatively how the design parameters affect the optimum solution. The proposed model demonstrates potential for use in decision making during the conceptual product design stage, when determining design variable values that meet desired lifecycle cost requirements is a goal.