Minimizing Life Cycle Cost and Environment Load in Chilled Water Supply System for Clean Rooms in Semiconductor Manufacturing Plant

Abstract

Semiconductor production lines are run all the year round and the electrical load is large. Thus their airconditioning load and operating hours are on the rise. Consequently, the operational cost accounts for a significant proportion of their production cost. Facilities that feed chilled water to cleanrooms are run for many hours, with a high loading factor, such that both their energy requirements and CO₂ emissions can be cut drastically by redesigning the existing plant. This report introduces a package of energy-saving concepts that have been successfully implemented in the refrigerating plant for a cleanroom dedicated to manufacturing semiconductors to promise reduction in both the life-cycle cost (LCC) and life-cycle CO₂ (LCCO₂). We have found that new energysaving facilities and maintenance routines and frequencies could be optimized to reduce the LCC by 172 million yen and LCCO₂ emissions by 14, 050t-C0₂ over a 10-year period.