1. Indirect cooling products can be divided into two types: mechanical ventilation indirect air cooling system and natural ventilation indirect air cooling system.
2. Indirect air cooling systems have been applied in the power industry for more than 50 years. And SPX has developed the indirect air cooling system for more than 30 years. In 1986, SPX successfully designed and supplied indirect air cooling systems to a power plant (6X690MW) in South Africa which started operation in 1992. Compared to other power plant in the world which has been put into operation, it has the largest indirect air cooling system in the world.
3. The exhaust steam of the steam turbine will be condensed by cooling water in a surface or injection type condenser. The cooling water which will be heated after heat exchange will return to the cooling triangle which surrounds the concrete tower under the action of circulating water pump. And the air flow which is formed by the natural ventilation cooling tower will travel through the cooling triangle.
4. The finned tube is also a key part of the indirect air cooling system just like the direct air cooling system. The indirect air cooling system of Shanghai Electric SPX uses 6-runner finned tubes, 4-runner finned tubes and double- runner finned tubes, which possesses excellent reliability and cooling performance.
5. SPX is the first company to design and apply two bundles of tubes which are arranged vertically （This design has been successfully tested and patented）. The technology is particularly suitable for large units and it has advantages of low the water lateral pressure and electricity consumption. In addition, it has been successfully applied to the recent indirect air cooling project of SPX.

The air-cooling technology and patents of SPX are transferred to the joint venture after the joint venture between Shanghai Electric and SPX. At the same time, Shanghai Electric SPX sets up R & D center in Shanghai. The SPX Air Cooling R&D Center in Europe is completely open to Shanghai Electric SPX. The technology will be updated from time to time, which makes the company become a leader in the industry.

Shanghai Electric SPX purchased the air-cooling departments of Germany Balcke Dürr in 2002 and bought air-cooling departments of Belgium Harmon in 2003, which is the source of air-cooling technology of SPX. After more than 100 years of research and development, our company has more than 250 world patents and becomes a leader in innovation solutions of power plant cooling system.

Air cooling products are mainly used for dry areas, which can effectively save water resources. Air cooling products of Shanghai Electric SPX are mainly used to directly or indirectly cool the exhaust steam of power station steam turbines.