Physical Life Design of Reusable Unit with Consideration of Time Series Behavior of Its Value and Demand

In the design phase of sustainable products involving reusable units, it is important to set an appropriate physical life span for a reusable unit from the viewpoint of decreasing the environmental load on earth. If a reusable unit has a short functional life or little demand, it having an excess physical life span will increase environmental impact. This study examines the optimal physical life span distribution of a reusable unit, which minimizes environmental impact per unit time, with consideration of the time series behavior of the value and demand of reusable units and sustainable products including reusable units. A discrete-event simulation model is developed for its purpose and statistical characteristics of the optimal physical life span distribution are derived under various environmental conditions