Abstract: In this paper, the air conditioning system of Suzhou Du Shu Lake gymnasium was retrofited. In consideration of the characteristics of the gymnasium, a magnetic levitation centrifugal unit & a gas vacuum hot water boiler was adopted to replace the original direct-fired lithium bromide unit. In addition, the airflow organization was redesigned, original system of the audience area seat air supply, has been changed, low and high position of the stadium air have been exchanged. Thus, the air conditioning effect was improved with problems solved of unit performance attenuation and heat storage of earthwork static box. At the same time, CFD simulation was used to verify the retrofit plan, and the results proved effective. Finally, the project has been completed, tested, and has achieved good results, which provides a reference for similar gymnasium air conditioning retrofit.

Key words: energy saving retrofit, magnetic levitation air-conditioning unit, airflow, CFD simulation