Abstract
The average life years of energy systems for supplying electricity, space heating and cooling, etc to buildings are estimated about 15 to 25 years. Therefore, it is necessary to renew or reconstruct these systems several times in the life of buildings of about 60 years. Moreover, the recent performance of equipment is upgrading distinctly because of the advance of technology. Therefore, proper renewal planning is becoming a very important task nowadays. In this paper, an optimal renewal planning method is proposed, by which the optimal renewal year and equipment selection can be determined to minimize the annual total cost of an energy supply system. By using this optimization method, a numerical study is conducted on the renewal planning for an office building with a total floor area of 15,000m^2. Consequently, it is clarified that the optimal renewal year can reduce the annual total cost by 8.2%.
