27. Sustainable Product Design and Development: TPI-Based Idea Generation Method for Eco-Business Planning and Eco-Product Development

Environmental consciousness has been growing in recent years, and product life cycle design that aims to maximize utility value while minimizing environmental load and cost should be implemented in addition to the environmentally conscious design of the product itself. In this context, many life cycle design tools have been proposed in recent years. Examples include life cycle scenario description tools, which support a designer in explicitly describing an expected life cycle scenario for a product, life cycle simulation (LCS) tools, and design guideline for product life cycle. However, it is not easy for a designer to derive a practical design solution for the product life cycle (e.g., product specifications and life cycle options for components) by using these tools. Life cycle scenario description tools alone cannot calculate the optimal values for design parameters and LCS tools, the model of which consists of a large number of interrelated parameters, and are too complex to calculate these values. In addition, developing a calculation model for a LCS tool is a time-consuming task.

To solve these problems, Total Performance Design (TPD) method has been developed, especially focusing on the balance of customer’s utility value of a product and its resulting environmental load and cost throughout the entire life cycle. In this method, Total Performance Indicator (TPI), which represents the environmental and economic performance throughout product life cycle, is used as an objective function and a design solution is derived as a set of life cycle option (e.g., reuse, recycling, upgrading, extension of physical lifetime) for each component, specification for each functional requirement, and product lifetime that maximizes TPI under given business environment.

Although this method was revealed to be useful through a case study, it was shown that the consideration of various eco-business strategies (e.g., product sales, lease and rental, and function selling) also plays an important role in improving TPI. For example, adequate control and management of operating conditions are effective for products which consume large quantities of energy and materials during their use stage. In this case, providing products with energy-saving service (e.g., ESCO business) is a promising approach. In addition to operating conditions, product lifetime and its physical wear and deterioration are also insufficiently controlled by product design alone. Therefore, the idea generation and decision-making process for eco-business strategy, as well as design of a target product itself, should be focused on.