The product was introduced and developed in 2002 and officially launched in both domestic and international markets in the beginning of 2004. It was specially designed for medium and high-grade urban buses. The combination of advection design, windward layout and the use of small-pipe-diameter rifled copper pipes improves the heat convection efficiency of the condenser by 25~30%. The cooling capacity, energy efficiency ratio, cooling capacity weight ratio and other technical index have reached advanced world standard and shown marked energy saving advantages. The refrigerant filling amount of the system is 30% lower than other types of bus air conditioners. The integrated structure makes the unit more impact and all facilities of the whole bus easier. The product is extensively applied to the high-grade customers of main domestic public bus markets.