Application of air-side economizer to air conditioning systems

Air-side economizers are widely used in all-air or air-water air conditioning systems of large and medium buildings in US as energy-saving equipment. ANSI/ASHRAE/IESNA Standard 90.1-2007 requires that each cooling system with a fan should include either an air-side economizer or a water side economizer. Presents the components, control types and four kinds operating modes of the fresh air economizers. Points out some problems tending to occur in their operation. Indicates that owing to the climate, the atmosphere pollution situation and the types of air conditioning systems in China, the fresh air economizers are inappropriate choice in air conditioning systems of large and medium buildings in China at present.