Abstract
Optimization for a certain building construction project is to find a solution with good balance between individual functional levels based on the design concept that meets client's needs including limited budget. However, due to complex relationship between individual design parameters, finding a balance point is a very difficult task. In this paper, an optimization technique considering the layered structure of design process is proposed to deal with such complex decision-making process in a rational way. In addition, taking indoor thermal environment in winter as an example, a demonstration of the proposed method is made. In the process of seeking for the optimum solution, the contribution ratio index is utilized to reduce calculation work of CFD analysis for estimation of air temperature distributions.