Energy-saving in Chilled-Water Supply System for Clean Room of Semiconductor Manufacturing Plant

-Variable Flow Control of Chilled-water and Addition of Drag Reduction-

Abstract

A semiconductor-manufacturing plant operates for long hours throughout the year. Clean rooms require air-conditioning year-round. To reduce the chilled water pumping power, we implemented two techniques: 1) implementing the adjustable control of water flow based on heat load, and 2) adding a surfactant. It is well known that a drag reduction effect can be obtained by adding a drag reduction additive. The air-conditioning system performance was immediately lowered after a drag-reducing additive charge in a short period. We explained the mechanism of degraded heat transfer performance , devised a countermeasure to minimize the adverse effect caused by the problem, and successfully reduced the pumping power . The annual energy-saving amount reached 2.1 x 10⁶ kWh, which is corresponding to reduction effect at 50.8% compared with the conventional system.